Viruses have been getting a lot of publicity recently with the rise of COVID-19 and its subsequent variants. But what actually is a virus? And how do viruses differ from other forms of pathogens? Recently, the rise of flu season has led to further questions about the differences between COVID-19 and influenza and how they can overlap. The term virus is broad and dynamic, encompassing a wide variety of pathogenic microorganisms that replicate inside living cells. Pretty much every type of living organism is a victim of viral infection to some extent. And viruses have left an indelible mark on…
Comments closedCategory: Biochemistry
Over the past couple of months, the resurgence of Covid-19 cases has been disappointing, to say the least. Just as we were gaining ground in the battle against this virus, it launched a brutal counterattack—the Delta variant. Covid-19 isn’t the first virus to employ this sort of adaptable retaliation survival strategy. In fact, quick mutation and evolution is a viral mainstay—one that enabled viruses to persist and become the most prevalent “organism” on Earth. But how does something that is essentially just some DNA wrapped in a protein shell evolve and change its strategy quickly enough to throw even 21st…
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In last week’s blog post, we explained the variety of molecular mechanisms that control gene expression and make up your epigenome. There is a lot scientists still don’t know about the complex machinations of your epigenome, and there’s even more they don’t know about how those changes respond to the environment and get passed down through generations. There is mounting evidence suggesting that some epigenetic changes are inherited, providing a pathway for behaviors, environments, and traumas to be passed on through generations. But how does this inheritance take place? And what could it mean for our health and the health…
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The last couple of months, we’ve talked a lot about the biopsychosocial model and how it explains some of the more complicated expressions of the brain. But biopsychosocial influences affect much more than just our brains. In fact, in the past few decades, there has been growing evidence that factors like environment and behavior can affect our bodies on a molecular level—through epigenetic markers. The term epigenetic refers to all of the molecular markers and modifications that change the way your DNA is read and interpreted. If DNA is the blueprint of life, then epigenetic markers are the labels and…
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The last few weeks, we’ve been discussing some of the complicated history and science surrounding vaccination and immunity. The strategic and targeted defensive strategies employed by the immune system are by no means perfectly impregnable, but they represent several millennia of evolution under fire. Pathogens have always had a leg up on multicellular organisms—evolving more quickly and chaotically, unburdened by the constraints of form and function. They aren’t very sophisticated, but in terms of sheer brute force, there are already more viruses on earth than there are stars in the entire universe. We are besieged on all sides by these…
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So far, we’ve discussed the historical legacy of vaccines as man-made enhancements for our existing immune weaponry. And we’ve taken a look at some of the extensive defenses of the innate immune system that guard us day and night from the billions of natural viruses and bacteria roaming the earth. But like any fortress, there are vulnerabilities to be exploited. One way or another, pathogens can occasionally slip through and start using the body’s resources to replicate and cause major damage. In these cases, the immune system has to switch tactics from defensive to offensive. The first step is raising…
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For most of history and the long origin story of vaccines, we have known very little about the mechanics of how bodies defend against disease. The practice of variolation—purposefully exposing individuals to dried infected material to stimulate immunity—was borne out of the simple observation that people who survive sickness don’t tend to get sick again. The science of immunity didn’t really fall under much scientific scrutiny until the 19th century after Edward Jenner made his pivotal cowpox/smallpox vaccine discovery. Cowpox and smallpox were clearly different diseases with differences in severity, animal host, and mode of transmission. But, despite these differences,…
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In 2016, in a Mexican hospital, Dr. John Zhang and his team delivered a baby boy who had three genetic parents. The boy was conceived via in vitro fertilization (IVF) and a novel method called spindle nuclear transfer. Spindle nuclear transfer involves transferring the mixed DNA from the mother and father to a new donor egg from a third person. In this case, the boy’s mother had a rare neurological disorder called Leigh syndrome caused by a defect in her mitochondrial DNA (mtDNA). As I mentioned last week, mtDNA is passed directly from the mother through the mitochondria in her…
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These past few weeks, I have written about many different genetic disorders and risk factors that stem from inherited errors in the DNA or mistakes in the division of chromosomes. But this week, I want to pivot a bit to talk about disorders that originate in a special form of DNA called mitochondrial DNA (mtDNA). Most of the DNA in your cells is housed within the nucleus, a central organelle (literally “little organ”—organelles are the “organs” of your cell with their own specific function). The nucleus keeps the DNA separate from all of the enzymes and chemical reactions of the…
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Last week, I explained that most individuals have 22 pairs of autosomal chromosomes and 1 pair of sex chromosomes (for a total of 46 chromosomes all together). But a subset of people has chromosomal abnormalities in the form of an extra chromosome or a missing chromosome. Most chromosome abnormalities are fatal and result in early miscarriages, but some abnormalities are survivable. One of the most common survivable chromosome abnormalities is Down syndrome, in which there are three copies of chromosome 21 instead of two (known as a trisomy). The extra chromosome copy causes physical, mental, and developmental abnormalities. There are…
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