C. Gatschet - BIOL 520

I am currently taking BIOL 676, Genetics of Microorganisms with Dr. Revathi Govind. During this class, we've gotten to learn a little bit about her research on Clostridium difficile. Commonly referred to as C. diff , this bacteria is gram-negative, anaerobic, spore-forming, and identified as one of the most prevalent causes of nosocomial antibiotic-associated diarrhea and colitis (Govind, et al. 2020). These spores reside within the large intestine as part of the microbiome, but are inactive in the presence of a normal gut microbiome. However, oftentimes in hospital settings, when patients are prescribed broad-spectrum antibiotics the normal gut microbes are killed off allowing the C. diff spores to germinate into vegetative C. difficile cells and begin wreaking their havoc. When the spores become viable cells, they begin to release toxins into their environment known simply as toxin A and toxin B, which target the epithelial cells of the inner intestinal wall, causing damage, and ...

With the recent and ongoing revolution of DNA sequencing technology, more and more species are able to be identified down to the genetic level. However, cryptic species have begun to reveal themselves through this readily available genetic information. Researchers, Pfenninger and Schwenk from Germany discovered that cryptic species are found in equal proportions across all major branches of the animal kingdom. This leads to the conclusion that there could be a multitude more species than we previously thought. Just last year, for example, an article was published by researchers in India studying the genus Ahaetulla, a type of peninsular Indian vine snake. Yes, this is the judgemental shoelace snake. (Do not boop, or you will get the hurt juice). When the first species of kind of vine snake, described by Linnaeus, was discovered, all the vine snakes in that region were thought to be part of a single species. However, as time drew on, the discovery of three additional species were added ...

Pipefish, along with seahorses, are both species in which the female deposits her eggs into the male, who carries and incubates them during gestation. In this case, the males must invest much more time and energy into their task of carrying the eggs than the female does. In a system such as this, with the "normal" sex roles reversed, sexual selection is also reversed. Therefore, we still see sexual dimorphism between the male and female, but it is the female who displays more of the related secondary sex traits, is visually more flamboyant, and participates in the courting of the male.  However, despite the divergence from what we normally observe, this mating system still proves the sexual selection hypothesis. The sex of the species who invests the most in the offspring is usually the one who chooses their mate, while the sex of the species who invests least in the offspring is the one who normally does the courting. https://onlinelibrary.wiley.com/doi/10.1002/ece3.4459  ht...