Posts Tagged ‘bacteriology’
“We’ve co-evolved with our microbes”*…
Allergies seem more prevalent and more severe these days because they are. Theresa MacPhail explains…
… Although allergy researchers may disagree on definitions, symptoms and methodology, all agree on one thing: Allergies have grown worse over the last few decades, and the staggering numbers of allergy sufferers worldwide is likely to continue growing. An estimated 235 million people worldwide have asthma, and anywhere from 240 to 550 million people globally may suffer from food allergies. Drug allergy may affect up to 10% of the world’s population.
There’s a consensus, looking at the last century’s data, that U.S. hay fever rates increased in the mid-20th century. Data suggests that the incidence of asthma increased beginning in the 1960s, peaking sometime in the 1990s. Since then, asthma rates have remained fairly constant. Respiratory allergic diseases and atopic sensitization (or skin allergy) have likely increased over the last few decades. But the most dramatic and visible increase has been the rise in global incidence rates for food allergies, which began in earnest in the 1990s and has grown steadily ever since.
There are, unsurprisingly, multiple theories about the cause. The hygiene hypothesis is one front-runner, positing that people who are “too clean” develop allergies. Many others think it’s our diet, that changes in the way we grow and prepare food have altered our gut microbiome, fueling allergies. Still others argue that manmade chemicals and plastics we encounter daily are making our immune systems more irritable.
What everyone agrees on is that the environment’s influence on our genes, or epigenetics, has played a large role in the rise of allergies, as does the makeup of our nose, gut and skin microbiomes. In the end, it appears, we are at least partially doing this to ourselves. Modern living is likely at the root of the recent rise in allergies…
Our very old immune systems can’t keep up with modern lifestyles and diets, leading to increases in all sorts of chronic health problems like allergies and obesity: “How Modernity Made Us Allergic,” from @TheresaMacphail in @NoemaMag. Eminently worth reading in full.
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As we stifle a sneeze, we might send infectious birthday greetings to Alfred Hershey; he was born on this date in 1908. A bacteriologist and geneticist, investigate bacteriophages, or phages—viruses that infect and replicate inside bacteria. In 1952, he and Martha Chase conducted the famous Hershey–Chase, or “Waring Blender” experiment. Their work confirmed that DNA, not protein, was the genetic material of life.
Hershey’s work with bacteriophage earned him a share of the 1969 Nobel Prize in Physiology or Medicine with Max Delbrück and Salvador Luria, “for their discoveries concerning the replication mechanism and the genetic structure of viruses.”
“To be overly concerned with the original materials, which are merely sentimental souvenirs of the past, is to fail to see the living building itself”*…
The human body replaces its own cells regularly. Scientists at the Weizmann Institute of Science in Rehovot, Israel, have finally pinned down the speed and extent of this “turnover.” About a third of our body mass is fluid outside of our cells, such as plasma, plus solids, such as the calcium scaffolding of bones. The remaining two thirds is made up of roughly 30 trillion human cells. About 72 percent of those, by mass, are fat and muscle, which last an average of 12 to 50 years, respectively. But we have far more, tiny cells in our blood, which live only three to 120 days, and lining our gut, which typically live less than a week. Those two groups therefore make up the giant majority of the turnover. About 330 billion cells are replaced daily, equivalent to about 1 percent of all our cells. In 80 to 100 days, 30 trillion will have replenished—the equivalent of a new you…
Our Bodies Replace Billions of Cells Every Day: “A New You in 80 Days.”
* Douglas Adams, Last Chance to See
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As we sail on the Ship of Theseus, we might spare a thought for Hans Ernst August Buchner; he died on this date in 1902. A bacteriologist, he was a pioneer in the field of immunology, the first to discover a substance in blood, gamma globulins, natural bactericides capable of destroying bacteria. He also worked with his brother Eduard Buchner, a chemist who won the Nobel Prize in 1907 for his work on fermentation (which helped pave the way for our understanding of the work of enzymes); Ernst had died in 1902, and so did not share in the honor.
“We mostly don’t get sick. Most often, bacteria are keeping us well”*…
E. coli bacteria
Food picked up just a few seconds after being dropped is less likely to contain bacteria than if it is left for longer periods of time, according to the findings of research carried out at Aston University’s School of Life and Health Sciences.
The findings suggest there may be some scientific basis to the ‘5 second rule’ – the urban myth about it being fine to eat food that has only had contact with the floor for five seconds or less. Although people have long followed the 5 second rule, until now it was unclear whether it actually helped.
The study, undertaken by final year Biology students and led by Anthony Hilton, Professor of Microbiology at Aston University, monitored the transfer of the common bacteria Escherichia coli (E. coli) and Staphylococcus aureus from a variety of indoor floor types (carpet, laminate and tiled surfaces) to toast, pasta, biscuit and a sticky sweet when contact was made from 3 to 30 seconds…
Read the reassuring details at “Researchers prove the five second rule is real.”
The [Five Second Rule] has many variations, including The Three Second Rule, The Seven Second Rule, and the extremely handy and versatile The However Long It Takes Me to Pick Up This Food Rule.
-Neil Pasricha
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As we waste not so as to want not, we might send synthetic birthday greetings to Ananda Mohan Chakrabarty; he was born on this date in 1938. A microbiologist with specialties in directed evolution and genetic engineering, he created a new single cell life form, the Pseudomonas bacterium (now called Burkholderia cepacia) while working at G.E. The microorganism had the had the potential to clean up toxic spills, due to its ability to break down crude oil into simpler substances that could become food for aquatic life (an ability possessed by no naturally occurring bacteria).
Chakrabarty applied for a patent on his creation– the first U.S. patent for a genetically modified organism. (U.S. utility patents had been granted to living organisms before, including two pure bacterial cultures, patented by Louis Pasteur. Chakrabarty’s modified bacterium was granted a patent in the U.K. before the U.S. patent came through.) He was initially denied the patent by the Patent Office because it was thought that the patent code precluded patents on living organisms. The case was appealed to the Supreme Court, where in 1980 the Justices granted the patent (Diamond v. Chakrabarty)– a decision that paved the way for many patents on genetically modified micro-organisms and other life forms, and catapulted Chakrabarty into the international spotlight.
Her Majesty’s Rat-Catcher…
Biblical Egypt had its plague of locusts, modern New York City is terrorized by bedbugs, and Victorian London had a serious rat problem. Rats scurried around the city chewing up food, clogging up drains, passing around diseases, and frightening ladies. The task of reining in the rodents fell to village farmers (desperate to save the gnawed legs of their livestock) and rat vigilantes who killed for commission or provided rats for popular dog and rat matches.
And then there was the rat’s most notorious enemy: Jack Black, Rat-Catcher to Her Majesty The Queen…
Read the extraordinary story of this scourge of rodentkind at Lapham’s Quarterly.
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As we shriek “eek!”, we might spare a thought for Kitasato Shibasaburo; he died on this date in 1931. A physician and bacteriologist, Shibasaburo discovered (essentially simultaneously with Alexandre Yersin) the bacterium Pasteurella pestis (now called Yersinia pestis), the infectious agent of bubonic plague. Shibasaburo was also the first to grow a pure culture of the tetanus bacillus.
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