Peter Voyvodic 🧬🍄
1.4K posts
@PVoyvodic
Synthetic mycologist and cell-free synthetic biologist, adventurous home cook, lover of bad puns
In the latest issue! Neuropeptides specify and reprogram division of labor in the leafcutter ant Atta cephalotes dlvr.it/TM8GVY
The only rule in biology is that there are exceptions to every rule. This is what makes biology infinitely exciting; even when you think you’ve got the complete view, the floor can drop out from underneath you at any given moment. Case-in-point: The nucleus is the thing that makes eukaryotes...well, eukaryotes. It's the part of the cell that stores the genome, separating DNA from the cytoplasm and other organelles. (Bacteria do not have nuclei.) For decades, scientists thought that each nucleus contains one or more haploid sets of chromosomes. But there are exceptions. Red blood cells, for example, don’t have nuclei at all. (They expel their nuclei during maturation to maximize hemoglobin concentrations.) Cells in the eye lens, too, lose their nuclei and organelles during differentiation, thus becoming transparent. And so on. But now there is yet ANOTHER exception to this rule, and it’s one I hadn’t seen before. For a study in Science, researchers discovered that two types of pathogenic fungi that infect plants, called Sclerotinia sclerotiorum and Botrytis cinerea, have two different nuclei. And instead of storing a full set of chromosomes in each nuclei, they instead “distribute their chromosomes such that each of their nuclei contains only a subset of the haploid chromosomes.” The authors confirmed this by throwing a kitchen sink of methods at these cells; chromosome counting, DNA measurements using flow cytometry, single-nucleus PCR, and more. Nobody knows why the fungi do this, but the scientists claim (in their discussion) that it could enable them "to respond and adapt more effectively to local environmental stresses within their extensive mycelial networks. Nuclear shuffling may facilitate the rapid generation of new genotypes, enhancing adaptability to changing environments.” There is also evidence that the chromosomes within each nucleus may briefly collide during cell division, before going back into their separate nuclei. This is a great paper. It is simple, to the point, and challenges the status quo. It has serious potential to become a “classic” of the genre. Link: science.org/doi/10.1126/sc…
RFK JR: And these are kids who will never pay taxes, they'll never hold a job, they'll never play baseball, they'll never write a poem. They'll never go out on a date. Many of them will never use a toilet unassisted
The Dangers of Mirrored Life 🦠 In a Science article published today, 30+ scientists call on the broader community to confront the serious risks of creating "mirrored" lifeforms. They lay out their case in a compelling, 300-page technical report. Check out our Special Report🔻
Chinese Hamster Ovary, or CHO cells, make roughly 70 percent of all F.D.A. approved biologics sold on the market. This includes bestsellers like Humira®, used to treat Crohn’s and rheumatoid arthritis, and Keytruda®, a cancer therapy. Despite their ubiquity in the pharmaceutical industry, though, the origins of CHO cells are extremely peculiar — it involves the Chinese Civil War and a smuggler. The story goes like this. In autumn 1948, as China's civil war entered its climax, a truck navigated the perilous roads from Peking to Nanking. Inside, a nondescript crate held twenty Chinese hamsters — ten males and ten females — each nestled in its own wood-shaving-lined compartment. The hamsters were a gift from Dr. H.C. Hu, of the Peking Union Medical College, to Dr. Robert Briggs Watson, an American physician working for the Rockefeller Foundation's International Health Division. Watson was retrieving the hamsters for his friend Victor Schwentker, a renowned rodent breeder in upstate New York. Chinese scientists had been studying these hamsters, native to northern China and Mongolia, since at least the 1910s. The hamsters have short gestation periods and natural resistance to human viruses — traits that made them ideal for scientific research. Schwentker wanted to get his hands on some. But with Mao Tse-Tung's communist forces advancing, he knew that acquiring these animals would soon become impossible. On December 6, the hamsters arrived at Watson's doorstep in Nanking, a city on the verge of evacuation. The Yangtze River was all that separated the capital from Mao's forces. Despite suffering from dysentery, Watson was preparing to flee. Against the counsel of both his Chinese colleagues and the American Embassy, he loaded the hamsters and his laboratory equipment into a station wagon on December 10 and drove eleven hours east, through the mud and rain, to Shanghai. The hamsters left China in December 1948, aboard one of the last Pan-Am flights out of that city. Watson was later accused of "war crimes" by Mao’s Chinese Germ Warfare Commission and tried in absentia for allegedly conspiring with Chinese nationalists to carry out a biological attack. Dr. Hu faced similar charges and was sent to a detention camp for six months. Upon arrival in San Francisco, the hamsters were shipped to Schwentker's farm in New York. After months of effort, Schwentker was able to domesticate and breed the hamsters, establishing the first colony outside of China by 1950. He then began selling and distributing the hamsters to American researchers. In 1957, a geneticist at the University of Colorado School of Medicine named Theodore Puck began seeking robust mammalian cell lines for genetic research. He obtained a single adult female Chinese hamster, extracted an ovary cell, and cultivated it in vitro, thus creating the first CHO cell line. Puck’s cells were both resilient and easy to work with. They grew quickly and could be maintained indefinitely, which was a big improvement for researchers struggling with short-lived mammalian cell cultures. Puck shared his CHO cells freely with the scientific community. This is an abbreviated version, basically, of how CHO cells became such a dominant cell line for the pharmaceutical industry. We learned about this tale via an excellent 2015 article in LSF Magazine, called “A Brief History of CHO Cells.” Highly recommended. biomanufacturing.org/uploads/files/…
