Molecule Illustrations

Wayne's Word Index Noteworthy Plants Trivia Lemnaceae Biology 101 Botany Scenic Wildflowers Trains Spiders & Insects Search

Illustrations Of Molecular Models
Simplified Explanations Of How These Molecules Function
Disclaimer: Some of these are undoubtedly oversimplified.
    COVID-19 Virus       Endemic vs. Pandemic  

W.P. Armstrong Updated 19 February 2022
  1. Lock & Key Model Of An Enzyme
  2. Model For Enzyme Block By Poison
  3. Sandwich Model Of A Cell Membrane
  4. Fluid-Mosaic Model Of Cell Membrane
  5. Type 2 (Non-Insulin Dependent) Diabetes
  6. Osmosis Through A Cell Membrane
  7. Cloverleaf Model Of A Transfer RNA
  8. The COVID-19 Pandemic Of 2000
  9. 4-Polypeptide Y-Shaped Antibody Model   
  10. Vaccines & Serums (Antiserums)   
  11. Antivenin For Bites Of Venomous Snakes   
  12. Immunotoxin: Antibody-Toxin Conjugate

1. Lock & Key Model Of Enzyme Specificity

The active site on the enzyme attaches to a substrate molecule (such as a disaccharide) forming an enzyme-substrate complex. While attached to the substrate, the enzyme causes a weakening of certain chemical bonds in the substrate molecule, resulting in a breakdown (hydrolysis) of the substrate into two smaller product molecules (such as two monosaccharides). The enzyme is unaltered during the reaction and is free to catalyze the breakdown of another substrate molecule. If the active site on the enzyme is blocked by a poison molecule, this vital hydrolysis reaction cannot occur. See the next section.

2. Active Site Of Enzyme Blocked By Poison Molecule

Dead steer in a pasture with several individuals of the toxic locoweed Astragalus oxyphysus in the foreground (white arrow). This notoriously poisonous locoweed covered many acres of nearby land (on the other side of the hill) where this unfortunate steer had been grazing. Contrary to the observations of several students, the steer in photo was NOT sleeping. I am reasonably certain that the steer consumed quantities of the locoweed. I attempted to get closer until a Kern County Sheriff stopped and asked what I was doing.

In the above illustration a poison molecule has bonded to the active site of an enzyme. Now the enzyme is unable to recognize the substrate molecule that it normally conjugates with because its active site has been blocked. In locoweed poisoning of livestock, the alkaloid swainsonine blocks a key enzyme called mannosidase. When the active site of mannosidase is blocked, it cannot catalyze the breakdown of the sugar mannose, resulting in a lethal accumulation of mannose in vacuoles of cells of the central nervous system (brain and spinal cord). The actual vacuoles are swollen organelles called lysosomes where the enzymatic breakdown process normally occurs. The afflicted animal becomes paralyzed and eventually dies. A similar scenario occurs in infants suffering from the storage disease mannosidosis. In this disease, the vital enzyme mannosidase is lacking due to a mutant recessive gene. At the present time there is no cure for this disease. It is passed on via heterozygous carriers, and shows up with a 25 percent probability when two heterozygous individuals have a child. One of the better known storage diseases is Tay Sachs Disease, in which nerve cells fill up with a lipid called ganglioside or GM2 because they lack the vital enzyme HEX A needed to break down GM2.

Competitive Inhibition

3. Sandwich Model Of A Cell Membrane

In the simplified "sandwich model" of a cell membrane, a phospholipid bilayer is sandwiched between two layers of protein. Having phospholipids (with phosphates) rather than ordinary lipids is essential because the lipid layer is permeable to polar water molecules.

4. Fluid-Mosaic Model Of Membrane Structure

A more accurate model shows large protein (glycoprotein) molecules embedded in the membrane. Some membrane proteins serve as carrier molecules in which molecules and ions (Na + and Cl -) pass through channels in the protein molecule. The movement of molecules may occur through facilitated diffusion in which carrier proteins are required (without the energy of ATP). The ions may also move against a diffusion gradient in a process known as active transport. Unlike facilitated diffusion, active transport requires ATP. Membrane proteins may also be associated with cell recognition in which patrolling T-cells and antibodies recognize the shape of membrane proteins as "self" or "foreign." These membrane proteins often contain unique carbohydrate chains (antennae) which are involved in the cell recognition process. Recognition glycoproteins may include receptor sites for some hormones and neurotransmitters and various blood antigens.

In the "fluid mosaic model" of membrane structure, the membrane is a fluid phospholipid bilayer in which protein (glycoprotein) molecules are either partially or wholly embedded. Electron micrographs of the membrane surface reveal scattered particles or minute "bumps" forming a mosaic pattern. The minute "bumps" represent large glycoproteins embedded in the membrane. The upper part of these glycoproteins projects out of the membrane surface, like the tips of icebergs emerging from the ocean surface. Like icebergs, only a small portion of the total molecule actually projects out of the membrane surface.

5. Type 2 (Non-Insulin Dependent) Diabetes

A good example of facilitated diffusion is the uptake of glucose by fat (adipose tissue) and muscle cells. This reaction is dependent on the hormone insulin. Insulin stimulates glucose uptake by fat and muscle cells by facilitated diffusion through the action of GLUT4 (Glucose Transport Protein 4). The mechanism is very complex and beyond the scope of this discussion. The process begins when insulin bonds to special insulin receptors on the plasma membrane. This results in the rapid fusion of cytoplasmic vesicles with the plasma membrane and the insertion of glucose transporters (GLUT4) into the membrane where they function as carrier proteins. Glucose molecules pass through channels in the carrier protein (see above diagram). When insulin is decreased, the GLUT4 transporters resume their inactive position within cytoplasmic vesicles away from the plasma membrane. Not all tissues utilize GLUT4 for the uptake of glucose. In fact, the brain and liver use a different transporter that is not insulin-dependent.

Dr. Richard Bowen at Colorado State University gave me permission to use his Animation For The Action Of Glut4 (Glucose Transport Protein 4); however, if your browser is not java-enabled, the animation will not be visible. Since it doesn't work properly on every browser and since many people are afraid of viruses and malware, their browsers are not java-enabled. I regrettably decided to remove this marvelous animation from my web page.

Professor Dr. Richard Bowen Home Page At CSU
  Prestigious Dr. Bowen at Colorado State University   
In type 2 (non-insulin dependent) diabetes, glucose won't pass through the plasma membrane. As of 2012, this syndrome is an epidemic in the U.S. Type 2 diabetes is also referred to as "insulin resistance." Consequently, more insulin is produced by the body and glucose increases to abnormal levels in the blood. This condition is especially common in obese people and is often related to poor diet and lack of exercise. According to ZengKui Guo (Lipids in Health and Disease 2007, 6:18), an excess of intramuscular triglyceride (fat) molecules may be a factor in muscle insulin resistance. A normal 8 hour fasting blood glucose level is typically below 100 (milligrams per deciliter). Two hours after dinner this reading may be up to 120 (or higher), depending on the amount and glycemic index of the food consumed. I have known colleages with blood glucose levels in the hundreds (200-300+)! This condition known as hyperglycemia can be life threatening. It can cause serious complications to vital organs, including neurological and cardiovascular damage, as well as damage to the kidneys and retina.

The above chart gives one a false sense of security because it does not tell the whole story. Even though AM & PM blood glucose readings are normal, a Hemoglobin A1c test of 6.3% indicates prediabetes. Diabetes is defined as "a clinical condition of elevated glucose concentration in blood." High A1c represents high glycation of hemoglobin protein, which is a substantially different biochemical abnormality compared with high blood glucose.

Diabetes was originally identified by the presence of glucose in the urine. Almost 2,500 years ago ancient healers noticed that sugar-loving ants were attracted to the urine of some individuals with a strange, debilitating illness. In the 18th and 19th centuries the sweet taste of urine was used for diagnosis before chemical methods became available to detect sugars in the urine. Tests to measure glucose in the blood were developed over 100 years ago, and hyperglycemia subsequently became the sole criterion recommended for the diagnosis of diabetes. Another modern test uses the percentage of hemoglobin in red blood cells with glucose attached (A1C test).

Honeypot ants (Myrmecocystus mimicus) attracted to sweet solution on facial tissue.

According to Dr. Chris Kresser (Chriskresser.com 1 March 2011), Hemoglobin A1c is not a reliable test to screen insulin resistance and diabetes. Red blood cells (RBCs) live an average of three months and glucose molecules form covalent bonds with amino acids in hemoglobin, a process called glycation. The number reported in the A1c test is the percentage of hemoglobin that has become glycated. For example, an A1c value of 6% means that 6% of the hemoglobin molecules in that person's millions of red blood cells have glucose attached. The main problem with this test is that there is a wide variation in how long RBCs survive in different people. According to M.A. Virtue, J.K. Furne, F.Q. Nuttall, and M.D. Levitt (American Diabetes Association, 2004), the lifetime of RBCs of diabetics may be as low as 81 days, while they may live up to 146 days in non-diabetics. If RBCs live longer, there will be more hemoglobin to accumulate glucose and hence higher A1c readings. In other words, RBCs that live longer have more time to pick up glucose molecules (more glycation). Conversely, diabetics may have falsely lower A1c levels because their RBCs have shorter life spans and didn't pick up as much glucose. However, I have also found major discrepancies in the readings on over-the-counter, finger-prick glucose meters, as much as 20 points or more.

Oversimplified diagram of the four main structural forms of protein: (1) Primary: A straight chain of amino acids; (2) Secondary: A helical coil of amino acids stabilized by hydrogen bonds; (3) Tertiary: Folding and looping of a coiled polypeptide stabilized by various types of bonds, including hydrogen bonds and disulfide bridges; and (4) Quaternary: Four tertiary proteins joined together. The various types of chemical bonds between loops and folds in the molecules are shown as short black lines.

In quaternary proteins such as hemoglobin, four tertiary proteins are joined together. A molecule of hemoglobin is composed of four polypeptides, each with 146 amino acids, a grand total of 584. Heat or weak acid solutions can destroy the hydrogen bonding causing the tertiary proteins to uncoil, a condition termed denaturation. This is why vinegar (acetic acid) can actually "cook" an egg white (albumen) without heat. Proteins in raw fish called seviche (ceviche) are denatured by citric acid when the fish are marinated in lime or lemon juice. Hemotoxic proteins at the site of a rattlesnake bite can also be denatured by an electrical discharge from a device similar to a stun gun.

Chemical Compounds In Plants & Animals (Part I)
  Chemical Compounds In Plants & Animals (Part II)  
A molecule of hemoglobin is composed of 4 amino acid chains (proteins): 2 alpha chains (red) and 2 beta chains (blue). Each chain also has an iron-containing heme group (green). Glucose will bond to certain positively charged chemical groups on the hemoglobin. HbA1c (A1c) is defined as hemoglobin with glucose bound at the beginning (N-terminal) of the beta chain. The total glycated hemoglobin will include A1c plus all the other hemoglobins that have glucose bound to lysine side chains and/or the N-terminal of the alpha chain. Generally about half of the glucose is bound to the A1c position with the other half bound at 3 or 4 other sites (lysines).

Hemoglobin image courtesy of Wikimedia Commons.
Spiking Blood Glucose Levels?

A diet consisting of numerous slices of toast covered with peanut butter and high fructose grape jelly could lead to glucose spikes and higher A1c levels over a period of months. This piece of toast was consumed by a prediabetic with an A1c value of 6.3 and normal blood glucose values (see above table). It did not spike the blood glucose level beyond normal readings. After on hour using 2 different glucose meters the readings were 99 and 101. Probably there would have been higher values after consuming 5 pieces of toast with additional grape jelly!

When I had normal blood glucose AM & PM readings but an elevated A1C, I was consuming large quantities of carbohydrates during daytime botany field trips. Perhaps these excessive grape jelly sandwiches over a 3 month period were reflected in my elevated A1C.

  1. Barnard, N.D. 2007. Dr. Neal Barnard's Program for Reversing Diabetes. Rodale Books, Inc., New York, NY 10017.

  2. Bloomgarden, Z.T. "What Is An A1c Test?" EmPower Magazine Vol.2 Issue2. Available at: http://www.empoweryourhealth.org/vol2-issue2/what-is-an-a1c-test Accessed on-line 29 May 2012.

  3. Bloomgarden, Z.T. "A1C: Recommendations, Debates, and Questions." Available at: http://care.diabetesjournals.org/content/32/12/e141.full Accessed on-line 30 May 2012.

  4. Bonora, E., and J. Tuomilehto. 2011. "The Pros and Cons of Diagnosing Diabetes With A1c." Diabetes Care 34, Supplement 2: 184-190 Available at: http://care.diabetesjournals.org/content/34/Supplement_2/S184.full.pdf+html Accessed on-line 30 May 2012.

  5. Bowen, R. 2009. Physiological Effects of Insulin. Available at: http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/pancreas/insulin_phys.html Accessed on-line 27 June 2010.

  6. Hyman, M. 2012. The Blood Sugar Solution. Little, Brown and Company, New York, NY 10017.

A Note About Starchy Foods Like Potatoes With High Glycemic Index

The glycemic index (GI) ranks carbohydrate-rich foods according to their effect on our blood glucose levels. Foods with a high glycemic index (greater than 70) release glucose molecules into the blood quickly. Foods with a low glycemic index have a value of 55 or below. If you are trying to lose weight or lower your risk of type 2 diabetes, it is wise to reduce your intake of sugar and foods with a high glycemic index. There are several glycemic index databases available on the Internet. Some of the values for popular foods are quite surprising. For example, watermelon has a high glycemic index (72) while carbohydrate-rich bananas and sweet potatoes have values of 51 and 48, respectively. Avocados are high in fat and low in starch. This does not mean that people with type 2 diabetes should avoid carbohydrates entirely, just consume them in moderation and lay off foods with a high glycemic index. Intracellular fat in muscle and fat tissue may affect insulin resistance, so reducing your intake of fat (especially saturated animal fat) is also important. Of course, getting plenty of cardiovascular exercise and maintaining a healthy body weight is also important. This is a very complicated subject and there are a lot of conflicting data and reports.

  Glycemic Index Database  

6. Diagram Of Osmosis Through A Cell Membrane

Osmosis: Movement of water molecules (blue circles) through a cell membrane (red) from a region of high concentration (inside cell) to a region of lower concentration (outside cell). Inside the cell the solution is hypotonic with a low solute (salt) concentration. Outside the membrane the solution is hypertonic with a high solute (salt ion) concentration shown by the orange circles. The membrane is not permeable to the salt ions. Since the concentration of water molecules per unit area is higher inside the cell than outside, water moves out of the cell.

The internal body fluids of a marine fish are hypotonic compared with the hypertonic sea water; therefore, water molecules diffuse out of the fish through the gill region. To cope with this steady loss of water, the marine fish has greatly reduced urine with little or no water loss, continuously drinks water, and excretes excess salt through the gills by active transport. Conversely, a freshwater fish is hypertonic compared with the water of a lake or pond; therefore, it continually absorbs water through the gill region. To cope with this steady influx of water molecules, the freshwater fish has copious urine, drinks very little water, and absorbs salts through the gills by active transport.

7. Cloverleaf Model Of Transfer RNA Molecule

Cloverleaf model of a transfer RNA molecule showing an attached amino acid at one end and an anticodon at the other end. The transfer RNA strand is composed of 80-90 bases (nucleotides) which are folded back on themselves to form three loops. At the base of each loop the base pairs are held together by hydrogen bonds (paired red dots). The terminal (lower) loop contains the anticodon AAA (base triplet in red). The specific anticodon for phenylalanine is AAA. Other amino acids have different anticodons. The corresponding base triplet on the messenger RNA strand is called a codon. The codon for phenylalanine is UUU.

An abbreviated model of transfer RNA showing the amino acid phenylalanine and the anticodon AAA.


8. SARS-CoV-2 Virus: The Cause Of COVID-19 Pandemic

Note: For several years during the covid crisis I have attempted to post interesting and accurate information about this contagious virus on Wayne's Word. With the publication of a new book by Paul A. Offit, M.D., an authority on this subject, I encourage everyone reading my page to read Dr. Offit's book: Tell Me When It's Over (2024), available on Amazon. It is a fascinating historical account of this virus, including how and where it started, details of how it affects our antibody and cell-mediated immune response, myths and misinformation about the virus and vaccinations, and much more.

Go To Latest Remarks 3: 17 July 2022
Go To Latest Remarks 2: 20 October 2021
  Explanation For Terms Endemic vs. Pandemic   
Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds, including respiratory tract infections that can range from mild to lethal. The general term "coronavirus" is derived from the Latin corona, meaning crown or halo. The name refers to the characteristic appearance of virions (the infective form of the virus outside a host cell) by electron microscopy, which have a fringe of surface projections (spikes) creating an image reminiscent of a crown or solar corona. In this illustration of a coronavirus virion, the club-shaped viral spike peplomers (glycoprotein spikes), colored red, create the look of a corona surrounding the virion, when viewed with electron microscope. For health care workers in contact with coronavirus patients, the CDC recommends a more specialized type of face mask called N95--one that is individually fitted to a person's face to create a seal and that filters out 95 percent of particles that are at least 0.3 microns in diameter. This is diameter of a coronavirus virion. [A micron (micrometer) is 1/1,000th of a millimeter or 0.001 mm]. According to World Health Organization, respiratory droplets (aerosol particles) that commonly spread COVID-19 virus are 0.5 -10 microns in diameter. Image accessed from Wikipedia 18 November 2020.

If you see the misleading statement on a popular doctor's TV program: "If light passes through you mask, throw it away," don't believe it. The above image shows translucent light passing through two popular, disposable, triple layer Costco masks. I would definitely throw away the above black cloth mask containing pores that the corona virus can easily pass through! In fact, you can easily blow out a candle wearing the above cloth mask! According to The Centers for Disease Control and Prevention (CDC), N95 respirator masks are recommended PPE supplies (personal protective equipment) for health care workers and other medical first responders. They are now available for the general public. Also be aware that there are counterfeit N95 respirator masks on the market.

In February 2021 Masks Were Required In All U.S. National Parks.
If You Can Blow Out A Candle Wearing Your Mask I Would Toss It!

Regarding N95 vs. KN95 masks, there is a lot of confusing information on the Internet. Both N95 and KN95 masks are made from multiple layers of synthetic material (typically a polypropylene polymer) and are designed to be worn over the mouth and nose. Masks made from polypropylene fibers provide both mechanical and electrostatic barriers. Straps behind your ear help to hold the mask in place. Both masks must filter out and capture 95 percent of tiny 0.3 micron particles in the air (hence the "95" in the names). The general consensus appears to be that N95 masks are the best, depending on the manufacturer; however, some references say that KN95 masks are just as good for filtering 95 percent of viral particles (virons). It is also important for the mask to make a good seal around the sides of face, while still allowing user to breath comfortably.

 Apparently N95 masks are also tested for fit. The strap positions in true N95 masks are different from KN95 masks: The upper strap goes behind head and the lower strap goes behind neck. In KN95 masks the straps just go behind ears. The best N95 and KN95 masks are only effective when worn once or twice; they are not meant to be washed and reused.

N95 masks must pass a rigorous inspection and certification process from the National Institute for Occupational Safety and Health (NIOSH), which is part of the CDC. Companies making KN95 masks, meanwhile, can seek approval from the FDA, through an emergency authorization for a foreign certification which meets the 95 percent filtration requirement. The FDA says the manufacturer of KN95 masks must also provide documentation that the masks and materials used are authentic; however, as I stated above there are many brands, some of which may be counterfeit. The following links include FDA Emergency Use Authorizations (EUAs) for personal protective equipment (PPE) and NIOSH Approved & Unapproved (Counterfeit) Masks.

  NIOSH-Approved N95 Face Masks (Facepiece Respirators):  

In January 2022 I posted a note on Facebook about how to differentiate between KN95 and N95 masks. I made up a short multiple choice quiz and added a little humor with some of the choices. I also included a couplet dichotomous key to types of face masks that I also thought was slightly humorous. This is the type of key used to identify species in Biology. From the lack of response and confusion from several friends, I guess my posting didn't go over that well. I have placed the following links to my quiz and dichotomous key if anyone is interested.

Wayne's Word Quiz On ID Of KN95 Vs. N95 Masks
  For Help On Quiz: Click On Couplet Dichotomous Key  

Coronavirus disease 2019 (COVID-19) is a contagious, respiratory and vascular disease caused by the severe, acute, respiratory syndrome coronavirus 2 (SARS-CoV-2) that is deadly for some people. According to Centers For Disease Control & Prevention (CDC), the principal mode by which people are infected with this disease is through exposure to respiratory droplets carrying infectious virus. It was first identified in December 2019 in Wuhan Province, China. Unfortunately, it was underestimated by many people, and was even played down by U.S. President Donald Trump during spring and summer 2020. This delay and failure to social distance and wear protective masks cost hundeds of thousands of Americans their lives, not to mention thousands in other countries. Unlike the U.S., Covid-19 was under control in some countries, such as South Korea (at least prior to December 2020), due to their stringent epidemic preparedness: Detection, tracing, containment & treatment.

Exponential Growth Equation & COVID-19
  COVID-19 & Ecological Importance Of Bats  

Outbreaks of emerging diseases have been linked to human destruction of nature. When tropical rainforests are cleared for grazing cattle, soybeans, oil palms, etc., or to build roads and settlements, wild animals are forced ever closer to humans and livestock, giving viruses an opportunity to escape from their original hosts.

The precise origin of the coronavirus COVID-19 (SARS-CoV-2) that has killed millions of people throughout the world has not been established as of June 2021. It is discussed in a recent article by Nicholas Wade "The Origin of COVID: Did People or Nature Open Pandora's Box at Wuhan?" in Bulletin of the Atomic Scientists (5 May 2021). Some scientists believe that it crossed into humans from an animal species; escape from a virus research lab in Wuhan, China is another hypothesis. Laboratory research has involved genetic manipulation of viruses to predict how they could infect humans. This research is called "gain of function," a term used to describe any field of medical research which alters an organism or disease in a way that increases pathogenesis, transmissibility, or host range (the types of hosts that a microorganism can infect). This research is intended to reveal targets to better predict emerging infectious diseases and to develop vaccines and therapeutics.

Furin Cleavage Site In SARS-CoV-2

Furin is a vital enzyme in humans coded by the furin gene. Some proteins are inactive when they are first synthesized. They must have sections removed in order to become active. Furin cleaves these sections and activates the proteins. Furin occurs in the spike glycoprotein of the COVID-19 virus. This is an oversimplified explanation of a very complicated molecular subject beyond the scope of Wayne's Word. The origin of SARS-CoV-2 furin cleavage site is a fascinating research topic for molecular biologists.

Since there are only 20 kinds of amino acids, there are more than enough codons to go around, allowing some amino acids to be specified by more than one codon. The amino acid arginine, for instance, can be designated by any of the six Messenger RNA codons CGU, CGC, CGA, CGG, AGA or AGG, where A, U, G and C stand for the four different RNA bases. Different organisms have different codon preferences. Human cells designate arginine with the codons CGT, CGC or CGG. According to Nicholas Wade's references, CGG is the least popular codon for arginine in coronaviruses.

  Origin of COVID: Did People or Nature Open Pandora's Box at Wuhan?  
The Wayne's Word Table of DNA Base Triplets, Codons & Anticodons

COVID-19 and mRNA Vaccines—First Large Test for a New Approach by Jennifer Abbasi
JAMA. 2020;324(12):1125-1127. doi:10.1001/jama.2020.16866 3 September 2020

Summary of vaccine mechanisms explained by University of Pennsylvania vaccinology professor Paul Offit, MD.

Current antiviral vaccine designs include 2 major categories: (1) protein based and (2) gene based. Protein-based vaccines deliver the immune system–stimulating antigen to the body. This category includes whole-inactivated (killed) vaccines, as in the polio and flu shots, and subunit vaccines and virus-like particles, like in the hepatitis B and human papillomavirus vaccines.

Gene-based vaccines use a different stategy. They carry the genetic instructions (DNA or RNA) into the host’s cells to make the antigen, which more closely mimics a natural infection. In the case of coronaviruses (an RNA virus), the antigen of interest is the surface spike protein (glycoprotein) the virus uses to bind and fuse with human cells. “You’re not giving them the protein—you’re giving them the genetic material (Messenger RNA) that instructs the cells how to make the spike protein, to which they make an antibody response that hopefully is protective." When these genetic instructions (mRNA) are injected into the upper arm, the muscle cells translate them to make the viral protein directly in the body. I.e. transfer RNA (tRNA) molecules, each with their respective amino acid line up along m-RNA strand at ribosomes in cytoplasm of cells. This is called "translation." The completed amino acid chain (polypeptide) mimics the outer spike protein of virus. Your immune system produces antibodies that recognize and attack this protein on surface of coronavirus.

  Simplified Animated Gif Of Translation  

Unlike conventional vaccines, mRNA vaccines aren’t grown in eggs or cells, a time-consuming and costly process. At their essence, these vaccines are simply chemicals catalyzed in a test tube or a tank. This makes them easier to develop quickly and—at least theoretically—at scale, although they’ve never been mass-produced before.

According to Weissman, mRNA vaccines also have an advantage over DNA vaccines. In a DNA vaccine, the genetic material must first enter the host cell’s nucleus. From there, messenger RNA is created by the process of "transcription." It travels out of the nucleus into the cytoplasm, where protein is formed from it. However, genetic information can only enter the nucleus when the cell is dividing, making the process inefficient. There are fewer steps in protein synthesis with mRNA vaccines (i.e. they don't require the transcription steps of DNA). In addition, the mRNA must be edited before it leaves the nucleus of eukaryotic cells. The initial m-RNA transcribed from the DNA (gene) is modified (shortened) before it leaves the nucleus. Sections of the m-RNA strand called introns are removed, and the remaining portions called exons, are spliced together to form a shortened (edited) strand of mature M-RNA that leaves the nucleus and travels to the ribosome for translation into protein. MRNA may also be safer than DNA vaccines because it doesn’t enter the cell’s nucleus, so the chance of its integration into human DNA is believed to be very low. In addition, the body breaks down mRNA and its lipid carrier within a matter of hours, alleviating some concerns about long-term risks.

Update 29 March 2022

A study by scientists at Lund University, Sweden showed that Pfizer COVID-19 mRNA vaccine BNT162b2 was reverse transcribed into DNA in a human liver cancer cell in vitro. The implication here by some people is that this DNA could enter the DNA of nuclei and become part of human genome; however, the article does not say that: Current Issues in Molecular Biology 2022, 44, 1115–1126. https://doi.org/10.3390/cimb44030073

"At this stage, we do not know if DNA reverse transcribed from BNT162b2 is integrated into the cell genome. Further studies are needed to demonstrate the effect of BNT162b2 on genomic integrity, including whole genome sequencing of cells exposed to BNT162b2, as well as tissues from human subjects who received BNT162b2 vaccination."

According to Health Feedback, the study was factually inaccurate. It did not show reverse-transcribed DNA entering the nucleus. It also didn’t show that the DNA was integrated into the cell’s genome: https://healthfeedback.org/claimreview/study-lund-university-didnt-show-covid-19-mrna-vaccines-change-dna-epoch-times/)

"Unsupported: The experimental system used in the Lund University study is artificial. For example, it used liver cancer cells growing in the laboratory, which aren’t representative of healthy cells or a human being, to study whether the vaccine mRNA was reverse-transcribed. The study’s results therefore cannot be extrapolated to people."

  DNA Structure & Function: See Transcription & Translation  

This rapid degradation of mRNA raises questions about the vaccines’ protective duration. Of added concern for vaccine durability, researchers in Hong Kong recently confirmed that a man with SARS-CoV-2 was later reinfected, although his second case was asymptomatic. Yang and colleagues found that antibodies rapidly wane among patients with mild COVID-19. The current candidates’ 2-dose regimens could help to overcome this, Yang noted, and their cell-mediated immunity (T-cells) should provide additional immunity.

The most important challenge for development of a mRNA vaccine remains its inherent instability, because it is more likely to break apart above freezing temperatures. The Pfizer mRNA vaccine will need to be optimally stored at minus 94 degrees Fahrenheit and will degrade in around five days at normal refrigeration temperatures of slightly above freezing. Pfizer is developing shipping containers using dry ice to address shipping constraints. In contrast, Moderna claims its vaccine can be maintained at most home or medical freezer temperatures for up to six months for shipping and longer-term storage. The Pfizer vaccine requires a 2nd shot 21 days later. Moderna claims its vaccine can remain stable at standard refrigerated conditions, of 36 to 46 degrees Fahrenheit, for up to 30 days after thawing, within the six-month shelf life. The Moderna vaccine requires a 2nd shot 28 days after 1st injection. When I received my 1st Pfizer shot it seemed like there was very little in the injection until I realized it came from a multidose vial: Up to 6 doses per vial (0.3 mL per dose).

Clinical trials of the Pfizer and Moderna vaccines found that both do a good job preventing symptomatic COVID-19 disease, including severe COVID-19. However, the trials did not measure whether a person who is vaccinated is less likely to spread the virus to someone else. It is recommended that people who have been vaccinated with active immunity continue to wear masks because they still may pick up the virus through their nostrils and mouth. Like some bats, they may be asymptomatic for COVID-19 and still spread the virus to other people and possibly animals. There are still a lot of unknowns with this pandemic.

Oxford/AstraZeneca has announced an effective vaccine containing a virus that causes the common cold in chimpanzees. It is based on a different technology than the two recent “mRNA” vaccines from Pfizer/BioNTech and Moderna, both of which performed well against Covid. [As stated above, the Pfizer-Moderna vaccines contain m-RNA in microscopic oil droplets rather than another virus.] The chimp virus in AstraZeneca vaccine is modified so it cannot multiply and cause disease in the body. It is then loaded up with the gene for the coronavirus spike protein. When the vaccine is injected, the chimp virus delivers the coronavirus gene to human cells which start to churn out the spike protein. These are detected by the immune system which produces antibodies that can attack the real coronavirus should the person become infected in the future. Oxford’s vaccine can also be stored in standard refrigerators, making distribution far easier. Johnson & Johnson also announced an adenovirus-based vaccine that revolves around the use of an inactivated common cold virus, similar to what AstraZeneca utilizes. Early trials look promising because it requires a single shot and stimulates antibodies and T-cells. Other coronavirus vaccines are under development and use the virus itself in a weakened or inactive form. This is the same approach used in highly effective vaccines for polio and measles.

Three major COVID-19 vaccines are compared in the following chart, although recent articles in Wired, The New York Times and Associated Press report misleading (questionable) trial data from the AstraZeneca vaccine. On a positive note, the AstraZeneca vaccine could be sent without refrigeration to poor countries who desperately need it. As of 8 Dec. 2020 the Pfizer + German partner BioNTech vaccine is being released in the U.S. and UK. It is reportetly 95% effective. The vaccine is designed for two doses, 21 days apart.

The Trump administration last spring made a deal for 100 million doses of the Pfizer vaccine candidate, but turned down an offer to reserve additional doses, according to Scott Gottlieb, current Pfizer board member and former FDA commissioner: “Pfizer did offer an additional allotment coming out of that plan, basically the second-quarter allotment, to the US government multiple times – and as recently as after the interim data came out and we knew this vaccine looked to be effective.” In order to maintain minus 94 degrees Fahrenheit, the Pfizer vaccine must be shipped in dry ice (solid form of carbon dioxide), a boon to the dry ice industry.

More Information About COVID-19 Vaccine
  Compare Corona Virus On Table Of Cell Sizes  

Excellent Explanation Of COVID-19 Vaccines From CDC

How COVID-19 Vaccines Work:

COVID-19 vaccines help our bodies develop immunity to the virus that causes COVID-19 without us having to get the illness. Different types of vaccines work in different ways to offer protection, but with all types of vaccines, the body is left with a supply of “memory” T-lymphocytes as well as B-lymphocytes that will remember how to fight that virus in the future.

It typically takes a few weeks for the body to produce T-lymphocytes and B-lymphocytes after vaccination. Therefore, it is possible that a person could be infected with the virus that causes COVID-19 just before or just after vaccination and then get sick because the vaccine did not have enough time to provide protection.

Sometimes after vaccination, the process of building immunity can cause symptoms, such as fever. These symptoms are normal and are a sign that the body is building immunity.

Types of Vaccines:

Currently, there are three main types of COVID-19 vaccines that are or soon will be undergoing large-scale (Phase 3) clinical trials in the United States. Below is a description of how each type of vaccine prompts our bodies to recognize and protect us from the virus that causes COVID-19. None of these vaccines can give you COVID-19.

1. mRNA Vaccines: Contain material from the virus that causes COVID-19 that gives our cells instructions for how to make a harmless protein that is unique to the virus. After our cells make copies of the protein, they destroy the genetic material from the vaccine. Our bodies recognize that the protein should not be there and build T-lymphocytes and B-lymphocytes that will remember how to fight the virus that causes COVID-19 if we are infected in the future.
Company Name: Pfizer, Moderna

2. Protein Subunit Vaccines: Include harmless pieces (proteins) of the virus that cause COVID-19 instead of the entire germ. Once vaccinated, our immune system recognizes that the proteins don’t belong in the body and begins making T-lymphocytes and antibodies. If we are ever infected in the future, memory cells will recognize and fight the virus.
Company Name: Novavax, Sanofi

3. Vector Vaccines: Contain a weakened version of a live virus—a different virus than the one that causes COVID-19—that has genetic material from the virus that causes COVID-19 inserted in it (this is called a viral vector). Once the viral vector is inside our cells, the genetic material gives cells instructions to make a protein that is unique to the virus that causes COVID-19. Using these instructions, our cells make copies of the protein. This prompts our bodies to build T-lymphocytes and B-lymphocytes that will remember how to fight that virus if we are infected in the future.
Company Name: AstraZeneca, Janssen (Johnson & Johnson), Sputnik

4. Whole Killed Vaccines: Sinovac

Testing For Presence Of COVID-19 In An Infected Person

Testing of COVID-19 is largely dependent upon reverse-transcription polymerase chain reaction (RT-PCR), based on its ability to amplify and detect presence of SARS-CoV-2 (The Actual Virus Causing COVID-19 Disease) in upper respiratory tract specimens. In addition to the gold standard RT-PCR, serological analyses (most commonly enzyme-linked immunosorbent assay- ELISA) to detect presence of anti-SARS-CoV-2 antibodies has also become a widespread diagnostic means especially useful in identifying the asymptomatic infected and/or recovered population. In the latter test, some people have tested positive after getting their double dose of M-RNA vaccines because of the presence of anti-SARS-CoV-2 antibodies. Is this because of antibodies from previous infection or from the vaccination? According to CNN Health (4 Feb 2021), the AstraZeneca vaccine appears to substantially reduce transmission to others; however, its current efficacy is 70% compared with 95% for M-RNA Pfizer and Moderna vaccines.

In addition to antibodies, researchers are also investigating cell-mediated immunity in SARS-CoV-2 infections involving cytokines and T-cells. In fact, our well developed cell-mediated and antibody-mediated immune responses can overreact to the SARS-CoV-2 virus. Severe COVID-19 cases in some people may involve a "cytokine storm" or cytokine release syndrome (CRS), a massive immune response in the lungs that can be fatal. It is like the immune system is overreacting and causing inflammation and collateral damage to lung tissue. The poison oak rash is a well-known cell-mediated immune response in which T-cells attack the poison oak allergen (urushiol) in your skin. During the attack, surrounding epidermal cells are also destroyed, thus producing an itchy rash with oozing lymphatic fluids.

Antigen home test kits detect proteins from the virus. They are not as sensitive or accurate as molecular (PCR) tests conducted in laboratories. A positive antigen test result is more reliable than a negative result. In fact, a negative result may not rule out infection. In a recent conversation with person in my local CVS Pharmacy Department, I was told that negative results with some home tests are only 50% accurate. This seems very low, like flipping a coin; however, there are other factors affecting accuracy of a home test.

  Poison Oak: More Than Just Scratching The Surface  

CNN Health published an on-line article by Brenda Goodman (6 April 2022) about how Covid-19 infections can trigger a massive cytokine storm. The mechanism is similar to the cell-mediated immune response to the allergen urushiol in poison oak. The article refers to a detailed study published in the peer-reviewed journal Nature:

Junqueira, C. et al. 2022. "FcyR-Mediated SARS-CoV-2 Infection of Monocytes Activated Inflammation." Nature https://doi.org/10.1038/s41586-022-04702-4 (2022).

Summarized from CNN article: From the early days of the pandemic, doctors noticed that in severe cases of Covid-19 most of the internal tissue damage wasn't directly caused by the virus itself. It was caused by immune reactions triggered by the body to fight the infection. Researchers knew that these so-called cytokine storms were damaging, but they didn't know why the SARS-CoV-2 virus was setting them off. A new study published in the journal Nature explains how these immune reactions happen to Covid-19 patients. The study revealed that the SARS-CoV-2 virus can trigger certain kinds of immune cells called monocytes and macrophages ("killer T-cells"). These are front-line white blood cells that circulate in the blood and tissues. Their search & destroy mission is to attack pathogens. They do this by cell-eating (phagocytosis).

Monoclonal Antibodies: The Possible Answer To COVID-19 Crisis
Summarized From American Medical Association Patient Page

Monoclonal antibodies have an advantage over other types of treatment for infection because they are created to specifically target an essential part of the infectious process. A monoclonal antibody is created by exposing a type of white blood cell (antibody-producing B-lymphocytes) to a particular viral protein, which is then cloned to mass produce antibodies to target that virus. Prior to COVID-19, monoclonal antibodies were developed to treat several viral infections, such as Ebola and rabies.

Monoclonal antibodies work by binding to their specific targets – for example viruses, bacteria or cancerous cells – and making them harmless. They bind to their specific target, without harming anything else in their way. This target is not always a "foreign intruder," like a virus. Antibodies can be designed to attach to different molecules in the body, for example, to turn down the immune response when it overreacts; this phenomenon, which also happens with some COVID-19 patients, is called a "cytokine storm." Due to their numerous applications, monoclonal antibodies have been safely and effectively used to treat a growing number of diseases, some of which were difficult to treat in the past.

Illustration from JAMA Patient Page (American Medical Association )

  Jama Patient Page  

Do COVID-19 Vaccines Contain Fetal Cells Or Tissue?

The Following Is From Infectious Disease Expert Dr. James Lawler, Nebraska Medicine

1. No, the COVID-19 vaccines do not contain any aborted fetal cells.

2. However, Pfizer and Moderna did perform confirmation tests (to ensure the vaccines work) using fetal cell lines. And Johnson & Johnson uses fetal cell lines in vaccine development, confirmation and production.

3. But it's important to have the full context: Fetal cell lines are not the same as fetal tissue.

4. Fetal cell lines are cells that grow in a laboratory. They descend from cells taken from elective abortions in the 1970s and 1980s. Those individual cells from the 1970s and 1980s have since multiplied into many new cells over the past four or five decades, creating fetal cell lines. Current fetal cell lines are thousands of generations removed from the original fetal tissue. They do not contain any tissue from a fetus.

Concluding Remarks About COVID-19 Variants

As of February 2021 countless trillions of SARS-CoV-2 virus particles are rapidly multiplying in milillions of people and infected animals throughout our planet. They are constantly evolving slightly different strains (mutants), some of which have spike glycoproteins that our vaccine-induced antibodies may not recognize. Most vaccines use a recombinant spike glycoprotein: either mRNA based (the Moderna and Pfizer–BioNTech vaccines), via an adenovirus vector (the Oxford–AstraZeneca, CanSino, and Johnson & Johnson vaccines), or via injection of the protein itself (the Novavax vaccine). Keeping up with these variants is a tremendous task that will undoubtedy require annual booster vaccines, possibly multivalent to protect against different strains from different countries. At present there are new virulent strains from the UK, Brazil, South Africa, California and India, all evolving independently of each other on distant continents. This is evolution and natural selection in action. Mutations occur when the virus reproduces. Vaccine-resistant & antibody-resistant strains may evolve by chance during this process. Unfortunately, most people do not understand viral evolution. In my opinion (as of 20 March 2021) people are getting too complacent about the proper precautions for preventing COVID-19 infections and the spread of viral variants. Vaccinated people are planning get-togethers with family and friends in the coming months. Even with outdoor social distancing you remove your masks when eating, and still go into host's house to use restrooms, etc. When the outdoor temperature is too cold or it is getting dark, people often go inside.

New Rules From CDC As Of 13 May 2021

The Centers for Disease Control and Prevention (CDC) has amended its guidelines for fully vaccinated Americans, no longer recommending masks indoors or outdoors, including in crowds, CDC Director Rochelle Walensky announced at a White House briefing Thursday.

"If you are fully vaccinated, you can start doing the things that you had stopped doing because of the pandemic," Walensky said, announcing the sweeping change. "Anyone who is fully vaccinated can participate in indoor and outdoor activities, large or small, without wearing a mask or physical distancing."

Considering the opening paragraph in this "Concluding Remarks," Wayne's Word is concerned about these new relaxed rules regarding mask-wearing and social distancing:

1. How can you be sure that other people near you have been fully vaccinated (i.e. 2 weeks following final dose)?

2. What about children who have not been vaccinated?

3. If you have an autoimmune condition or are taking medications that weaken your immune system, you may NOT be fully protected even if you are fully vaccinated.

4. Depending on type of vaccine, you can still be infected by the virus and pass it to someone else, even if you are fully vaccinated.

While the new guidance is a positive step, the vast majority of people need to be fully vaccinated before COVID-19 precautions can be lifted broadly. Until then, it is important that everyone continues to adhere to public health mitigation measures to protect the large number of people who remain unvaccinated.

CDC recommends that fully vaccinated people continue to take these COVID-19 precautions when in public, when visiting with unvaccinated people from multiple other households, and when around unvaccinated people who are at high risk of getting severely ill from COVID-19.

Please Read The Following From CNN Sat.15 May 2021:

David Holtgrave, Ph.D., is the dean of the University at Albany School of Public Health and a SUNY distinguished professor. His three-decade career in public health has included senior positions at CDC, Emory University and Johns Hopkins University, and he served on the Presidential Advisory Council on HIV/AIDS during President Obama's administration. Eli Rosenberg, Ph.D. is an associate professor of epidemiology at the University at Albany School of Public Health. His research focuses on understanding transmission, prevention, and policies related to HIV, viral hepatitis, and emerging infectious diseases, including Covid-19. The opinions expressed in this commentary are their own. View more opinion on CNN.

(CNN) If you have questions after the US Centers for Disease Control and Prevention declared on Thursday (13 May 2021) that it was safe for Covid-vaccinated persons to cast aside masks and social distancing in outdoor and indoor spaces, with a few exceptions, such as on airplanes and trains and for immunocompromised persons, then you are not alone. While we agree that the current vaccines with emergency use authorizations in the US have outstanding effectiveness and should be fully utilized, and that their use makes a great difference in the severity of Covid-19 illness, hospitalizations and deaths, the CDC should better articulate the case for this policy relative to the numerous drawbacks. Yes, it's a good idea to bribe people to get vaccinated. Unfortunately, we are still not across the finish line in the US pandemic. There is still a Covid-19 death about every 2.5 minutes in the nation, and serious racial and ethnic disparities exists (e.g., in disproportionate access to vaccination services). There are six major concerns about the decision to roll back some key safety measures when in fact we need all of the tools we have in the Covid-19 prevention toolbox for perhaps just a short time longer. Please click on following link:

  CNN Article About May 13 Relaxed CDC Guidelines  

A central mistake in public health is easing infectious disease control efforts just before crossing the finish line. Unfortunately, and we suspect inadvertently, that is what the CDC did on Thursday 13 May 2021.

Latest Remarks

COVID-19 Addendum 17 July 2021: Are People Too Complacent?

As of 17 July 2021 there are still numerous people in the United States who refuse to get their COVID-19 vaccinations that are readily available. The reasoning of many is quite illogical. Some choose not to be vaccinated for political reasons, while others think the entire pandemic is a government plot or conspiracy. Many people have been misled by erroneous social media or other misinformed people that the vaccine is not safe or may cause further health complications. COVID-19 can definitely cause long-term damage to other organs, such as scar tissue in the lungs affecting tiny air sacs (alveoli) and long-term breathing problems. Whatever their reasoning, they are in grave danger due to the Delta variant that is spreading rapidly in unvaccinated populations. This is a virulent, very contagious strain that is soaring like wildfire in other countries, such as England. Not only does it infect unvaccinated populations, it spreads rapidly and during its multiplication within host cells it can mutate into variant forms, some of which could be more resistant to present vaccines. In fact, some medical experts have recommended that people should wear masks again, particularly in unvaccinated areas of the United States and public indoor settings.

Note: Vaccinated people can be infected with the Delta variant (breakthrough infections); however, symptoms of the disease are generally minimal and not life-threatening compared with unvaccinated persons. The problem here is that the Delta virus still resides in the nasal pharynx of vaccinated people and can be transmitted to vulnerable, unvaccinated children and adults. The bottom line here is GET VACCINATED.

If you are reading this and you haven't been vaccinated, please get your free vaccine ASAP. This will hopefully prevent the spread of this terrible virus, and most importantly, save lives!

[Note: There are rare cases of a severe allergic reaction to mRNA COVID-19 vaccine known as anaphylaxis. In these rare cases the CDC recommends that 2nd shot of vaccine not be given.]

Update Regarding Not Getting Covid-19 Vaccine By Anti-Vaxxers:

Some people are advocating a natural selection viewpoint (which one news reporter incorrectly called social dawinism): Unvaccinated people infected with COVID-19 illness who develop their own antibodies and survive the infection by natural immunity will pass on their genes; weaker people who die from COVID-19 will be weeded out by natural selection. The problem here is that people who become infected are allowing the virus to spread and mutate in the population and possibly develop more resistant strains.

The following article by Emanuel Goldman in Proceedings of the National Academy of Sciences of the United States is a much more logical and scientifically accurate response to these anti-vaxxers:

"How the unvaccinated threaten the vaccinated for COVID-19: A Darwinian perspective". PNAS September 28, 2021 118 (39) e2114279118; https://doi.org/10.1073/pnas.2114279118.

SARS-CoV-2 can mutate into many variants of the original agent. An unvaccinated pool of individuals provides a reservoir for the virus to continue to grow and multiply, and therefore more opportunities for such variants to emerge. When this occurs within a background of a largely vaccinated population, natural selection will favor a variant that is resistant to the vaccine.

So far, we have been lucky that the variants that have emerged can still be somewhat controlled by current vaccines, probably because these variants evolved in mostly unvaccinated populations and were not subject to selective pressure of having to grow in vaccinated hosts. Nevertheless, the Delta variant is exhibiting increased frequency of breakthrough infections among the vaccinated.

The real danger is a future variant, which will be the legacy of those people who are not getting vaccinated providing a breeding ground for the virus to continue to generate variants. A variant could arise that is resistant to current vaccines, rendering those already vaccinated susceptible again.

Progress we have made in overcoming the pandemic will be lost. New vaccines will have to be developed. Lockdowns and masks will once again be required. Many more who are currently protected, especially among the vulnerable, will die.

Law Of Declining Virulence

There is a lot of misleading information regarding SARS virus. One of these is the "Law of Declining Virulence" proposed by bacteriologist and comparative pathologist Theobald Smith (1859-1934) in the late 19th Century. It basically states that pathogens (including viruses) evolve to become more transmissable and less lethal over time. Some people have applied this to SARS-CoV-2, presumably because the Omicron variant is less virulent; however, many references say that this claim is false (healthfeedback.org & politifact.com). The previous websites site HIV, Ebola and MERS viruses that have become more lethal over time. Regarding SARS, Smith's law does not fit the new, highly transmissable B117 variant associated with an increased risk of death.

  Will Coronavirus Evolve To Become Less Deadly?  

Conclusion:

In addition to preventing placement on a ventilator and possibly saving your life, there is another important reason for being vaccinated: To Slow the spread & mutation rate of SARS-CoV-2. An international vaccination program can help to slow length of time virus multiplies in immunized individuals with optimal antibody & T-cell immunity, even those who become reinfected. Reducing time virus can multiply in these individuals before virus is destroyed by their immune system can also reduce chance of mutations in virus. Many antivaxxers fail to mention this very important reason for mandatory vaccinations. [In the interim, it is advisable to continue wearing a face mask in public and avoid close contact with indoor crowds.]

Unless people throughout all nations of the world are vaccinated, the virus will continue to mutate and spread. Just as predicted, a new virulent strain called the Omicron Variant has been discovered in South Africa. At this time (19 December 2021), RNA vaccines including 3rd booster can protect against the Delta & Omicron variants, although mild, breakthrough infections are still possible.

    A study conducted by researchers at the University of Maryland, USA, has highlighted the importance of coronavirus disease 2019 (COVID-19) vaccination in reducing the frequency of mutations in the delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). See summary by Dr. Sanchari Sinha Dutta (13 Aug 2021): Summary

Note: As Of 19 December 2021, COVID-19 Has Killed More Than 800,000 People In U.S.

As Of February 2022, Some Politicians (e.g. California) Consider COVID-19 An Endemic Disease Rather Than A Pandemic Disease; However, This Classification Seems A Little Premature. As of 20 February 2022, COVID-19 Variants Are Still An Epidemic In Some Parts Of The World. I Am Especially Concerned About Recent Misinformation Implying That The Threat Of This Contagious Disease Is Over When It Is Classified As Endemic.

An epidemic involves the uncontrolled spread of a disease, such as COVID-19, in a given region. This is how COVID-19 started out in Wuhan, China.

A pandemic involves the uncontrolled spread of a disease, such as COVID-19, throughout the world. This is what countries across the globe have experienced during the past 18 months.

An endemic disease is one that is consistently present with an overall stable growth rate, sometimes limited to a particular region or a particular time of year. This makes the disease's spread and rates much more predictable. In other words, an endemic disease is here to stay. Malaria in tropical countries is perhaps the best-known example of an endemic disease.

The following is from professor Aris Katzourakis, epidemiologist at the University of Oxford, UK, writing in the journal Nature (24 Jan. 2022):

"To an epidemiologist, an endemic infection is one in which overall rates are static--not rising, not falling. More precisely, it means that the proportion of people who can get sick balances out the basic reproduction number of the virus, the number of individuals that an infected individual would infect, assuming a population in which everyone could get sick. Yes, common colds are endemic. So are Lassa fever, malaria and polio. So was smallpox, until vaccines stamped it out. In other words, a disease can be endemic and both widespread and deadly. Malaria killed more than 600,000 people in 2020. Ten million fell ill with tuberculosis that same year and 1.5 million died. Endemic certainly does not mean that evolution has somehow tamed a pathogen so that life simply returns to normal."

NOTE: A botanical endemic is a plant confined to a particular region, such as an island or mountain. Endemic species are often distinct due to genetic variation during long periods of geographic isolation. See following image of San Clemente Island brodiaea (Brodiaea kinkiensis) off the coast of southern California. Owned and operated by the U.S. Navy, it also includes several federally endangered plant species found no where else on our planet. I was able to visit this island courtesy of the U.S. Navy and accompanied by two former ex-military students.

Is It Still Wise To Wear Mask Indoors In Crowded Places?

As of July 2022, there are 2 new very infectious subvariants of Covid-19 with new spike proteins that may evade current vaccines and active immunity. Another Omicron offshoot named BA.5 has three key mutations in its spike protein that make it both better at infecting our cells and more adept at slipping past our immune defenses. BA.2.75 has nine changes in its spike region that distinguish it from BA.2 and about 11 changes compared with BA.5, according to Tom Peacock, a virologist at Imperial College London. Hopefully, multivalent booster vaccines will be available to protect people against these latest variants.

9. Y-Shaped Immune Antibody Model With 4 Polypeptides

I first learned about antibody structure about 30 years ago while attending a lecture on recent advances in biology at University Hospital in San Diego. Some of the latest research was presented, including monoclonal antibodies.

Immune (IgG) antibody model composed of four polypeptides: Two heavy (H) chains (longer green chains), and two light (L) chains (shorter blue chains). The two combining sites where the antibody "arms" attach to antigens are shown in red. Using this model, a separate gene for every antibody protein is not necessary. 1,000 genes could produce 1,000 different L chains and 1,000 genes could produce 1,000 different H chains. With 2,000 genes 1,0002 or 1,000,000 different antibodies could be produced, simply by using different combinations of H chains and L chains. This may explain how organisms can produce antibodies against different antigens, even synthetic antigen proteins that animals have never been exposed to. Using this model, animals would not need separate genes for every antigen that they will ever encounter, they simply manufacture millions of different possible antibodies from a given number of genes for L chains and H chains.

One of the common on-line questions I receive on Wayne's Word is: Do we have genes for every possible antibody for every disease, even pathogens that we have never been exposed to. The answer is we don't need a separate gene for every antibody. Different combinations of L & H chains plus mutations can provide us with literally billions of different immune (IgG) antibodies.

10. Vaccines & Serums

Vaccines Resulting In Active Immunity

There are two general types of immunity to disease organisms, active immunity and passive immunity. Both types of immunity involve antibodies against a specific disease organism. Active immunity involves a complicated antibody-mediated immune response against antigens of the disease microbe. Since you actively produce the antibodies, this is called active immunity. In fact, some vaccines may even cause temporary discomfort, such as mild fever and muscular pain. The antibodies go on a "search and destroy" mission throughout your circulatory system. Their target is a specific microbe, such as a bacterium or virus. When the antigen combining sites of the Y-shaped immune (IgG) antibody recognize a specific antigen on the surface of a bacterium or virus, they bind to the antigen. Through a series of reactions the disease microbes are broken down and engulfed by special white blood cells (WBCs) called phagocytes. It should be noted here that antibodies also occur in many other groups of animals, including mammals, birds, amphibians, fish and invertebrates.

When vaccinated, you typically receive an intramuscular or subcutaneous injection of a vaccine. [The Sabin polio vaccine may be taken orally.] The vaccine contains a preparation made from a specific disease organism, such as polio, smallpox, whooping cough, typhus, bubonic plague, yellow fever, swine flu, etc. There is even a vaccine for anthrax, although it is currently (2001) in short supply and not available to the general population. Some vaccines are made from a weakened or dead strain of the actual organism. Other vaccines, such as Hepatitis B, are made from the genetically-engineered outer protein coat of the virus. Smallpox vaccine is made from a related virus called the cowpox virus. The dual immunity to these diseases came from the discovery that milkmaids (dairymaids) had developed an immunity to cow pox that also made them immune to smallpox. Multivalent (polyvalent) vaccines contain antigens of more than one microbe and induce antibody production against several disease organisms.

Most vaccinations require several injections in a series in order to provide immunity. In fact, the rabies vaccination involves more than 20 intramuscular injections in the abdomen; however, a more recent vaccine requires only five injections in the arm. Some vaccines are administered in the hip region because there are fewer nerves in this area. Your immune system responds to the vaccination by producing antibodies. Special ribosome-rich WBCs called plasma cells produce the actual antibodies. Plasma cells originate from WBCs called B-lymphocytes that are produced by lymphocyte stem cells in the bone marrow. The B-lymphocytes also produce special WBCs called memory cells which remain in your system for many years. The memory cells "remember" the specific disease organism and respond rapidly to a subsequent infection of the same organism by producing more plasma cells. Because of the production of memory cells, vaccines may prevent infections for many years. Some vaccines, such as diphtheria and tetanus, are made from soluble toxins rather than the actual organism. The toxins have been chemically altered and rendered harmless, but still induce antibody production. They are called toxoids because the are made from modified toxins of the organism. Like the B-lymphocytes, T-lymphocytes (T-cells) are also produced in the bone marrow. T-cells are another body defense mechanism called the cell-mediated immune response. This complicated immune response involves helper T-cells, effector T-cells, suppressor T-cells and killer T-cells. See the following link about poison oak, a remarkable cell-mediated immune response.

Serums Resulting In Passive Immunity

Passive immunity involves the intramuscular injection of a serum or antiserum containing ready-made antibodies. The antibodies are produced by another person or animal who has been exposed to specific antigens of a disease organism or toxin. If the serum is made from a toxin (such as tetanus toxin) it is called an antitoxin. Gamma globulin is the globular protein fraction of human blood containing many different antibodies. It is sometimes given for hepatitis A, immunodeficiency diseases, and other illnesses in which the immune system has been compromised. Gamma globulin is also given to boost the immune system prior to departing for a foreign country. Special precautions must be taken when administering serums containing antibodies made from other animals, such as goats and horses. Serums of equine origin (sometimes called horse serums) may trigger severe allergic reactions in hypersensitive people. These allergic reactions can be fatal if not treated quickly.

The RhoGam® given to an Rh negative woman after giving birth to an Rh positive baby is actually a serum containing anti-Rh antibodies. The antibodies seek out and destroy any residual Rh positive RBCs from the fetus that may have entered the mother's circulatory system. If the positive RBCs are destroyed in time, the mother will not be stimulated to produce anti-Rh antibodies. This is desirable in case she has another Rh positive baby. The RhoGam® serum contains anti-Rh antibodies obtained from Rh negative men who have been exposed to the Rh antigen (Rh positive RBC) or from Rh negative woman beyond child-bearing age or who will never bear children.

11. Antivenins For Bites Of Venomous Snakes

Rattlesnake antivenin is a polyvalent serum containing antibodies against several species of pit vipers of the family Crotalidae, including rattlesnakes (Crotalus), copperheads & cottonmouth moccasins (Agkistrodon), fer-de-lance (Bothrops) and bushmaster (Lachesis). Pit vipers are readily identified by their heat sensitive loreal pit between each eye and nostril. Horses are injected with venom to stimulate antibody production. Antibodies are removed from the horse's blood by centrifugation. The antibodies bind to the protein toxins of the injected venom, resulting in the destruction of the toxin before it damages blood cells and tissues of the victim.

Hemotoxins of pit vipers, such as rattlesnakes, can cause severe damage to tissues in the vicinity of the bite, and can cause gangrene in the afflicted extremities. Baby rattlesnakes generally inject all of their available venom, while large rattlesnakes may only inflict a "dry bite" resulting in fang punctures and bacteria without venom. They apparently strike and bite in a purely defensive action. This is why young rattlesnakes are often considered more dangerous. If the large rattlesnake injects a full-venom bite, it is considerably more dangerous. One of the reasons bites of the Central and South American bushmaster and fer-de-lance are especially dangerous to people is the volume of venom injected by these large pit vipers. Gram for gram, there are snakes of the cobra family with more deadly venoms. Large New World pit vipers have very effective movable fangs in the front of their jaws that literally stab their prey with a lethal dosage of venom. Other antivenins are available for venomous snakes of the viper family (Viperidae), cobra family (Elapidae) and sea snake family (Hydrophiidae). Some of these snakes have potent neurotoxic venoms that effect the nervous system of their prey.

Antivenin kit for North and South American pit vipers (Crotalidae). The kit includes a vial of freeze-dried, crystalized antivenin (A), a test vial (B), a syringe containing sterile water (C), and a plastic needle cover that serves as a push-pull rod when screwed into the rubber plunger on the syringe. The syringe is injected into the vial of antivenin crystals. The dissolved antivenin is then withdrawn back into the syringe. A drop from the test vial is used to perform a subcutaneous test. A wheal characterized by a circular reddish swelling indicates hypersensitivity to horse serums. The test drop can also be applied to the conjunctiva of the eye. Antivenin should only be administered by medical specialists who are trained to respond to possible lethal allergic reactions.

Two venomous pit vipers in San Diego County: Left: Red diamondback rattlesnake (Crotalus ruber ssp. ruber). Right: Southern Pacific rattlesnake (Crotalus viridis ssp. helleri)

Southern Pacific rattlesnake (Crotalus viridis ssp. helleri).

A large Southern Pacific rattlesnake (Crotalus viridis ssp. helleri) on Palomar Mtn.

Students often ask what is the deadliest snake in the world? There are approximately 50,000 human deaths per year caused by the bites of venomous snakes. Of this total number, the majority of deaths occur in India and Asia, mostly from bites of the Asian cobra and Russell's viper. This high death rate is proportional to the population density of this region, and frequent encounters with these two venomous species. Based on the number of deaths, these two snakes could be considered the most dangerous species on earth to humans; however, there are snakes with more toxic venoms. Some of the deadliest snakes include the inland taipan of Australia (Oxyuranus microlepidotus), Australian brown snake (Pseudonaja textilis), Malayan krait (Bungarus candidus), Australian taipan (Oxyuranus scutellatus), Australian tiger snake (Notechis scutatus), South Asian beaked sea snake (Enhydrina schistosa), Middle East & Asian saw-scaled viper (Echis carinatus), African boomslang (Dispholidus typus) and the death adder (Acanthophis antarcticus) of Australia & New Guinea. Depending on the herpetologist, other snakes that should be included on this list are the African black momba and both species of green mombas. Snakes with lower toxicity but which are quite deadly because of the volume of venom are the gaboon viper and king cobra. North American coral snakes (Micrurus fulvius) have a fairly potent venom drop-for-drop, but they are small snakes with small venom glands compared with the previous snakes. Large tropical American pit-vipers, such as the bushmaster and fer-de-lance, also can deliver a potentially deadly injection.

12. Immunotoxin: Antibody-Toxin Conjugate

Monoclonal antibodies are produced by a laboratory animal in response to an introduced tumor antigen on the membrane surface of injected tumor cells. The antibodies made for this particular tumor are taken from the animal and joined with a protein toxin (lectin), such as ricin from the castor bean (Ricinus communis). Now the antibody-toxin conjugate (called an immunotoxin) can be injected into a patient with this particular tumor. Like armed missles, the immunotoxins carry the deadly ricin directly to the targeted tumor cells.

Immunotoxin (Y-shaped antibody with attached protein toxin) attached to the membrane surface of a tumor cell. The specific antibody has two combining sites on the end of its "arms" that recognize a particular antigen on the membrane surface of the tumor cell. Using immunotoxins in chemotherapy is theoretically advantageous because only the targeted tumor cells are killed by the toxin, not all of the other normal cells that would be vulnerable during conventional treatments.

Return To The Biology 100 Home Page
Return To WAYNE'S WORD Home Page
Return To NOTEWORTHY PLANTS Page
Go To Biology GEE WHIZ TRIVIA Page
Go To The LEMNACEAE ON-LINE Page