by Christoph — Based on their knowledge of the morphology of P. syntrophicum MK-D1 from electron microscopy and their knowledge of its physiology from growth assays and genome analysis, Imachi, Nobu et al. (2020) propose a hypothetical model, the E3 model, of how the first evolutionary steps towards eukaryogenesis might have occurred in an ancestral archaeon living ~2 billion years ago. Read more →
Cultivating the Ancestors… (1|4)
by Christoph — ...is a metaphysical affair across all human cultures. For experimental biologists, it is the more prosaic, physical task of cultivating extant prokaryotic relatives of the ancestors of the eukaryotes in the lab. Or the 'most likely' ancestors of the eukaryotes, to be cautious when leaping back ~2 billion years in time. Now, meet the archaeon Promethearchaeum syntrophicum MK-D1, and its syntrophic companions. Read more →
Ancient Peptides to Combat Pathogens
Noteworthy — While many of our interactions with microbes are essential for our health, microbes are also well-known causes of diseases, such as the bubonic plague, that have decimated populations. We are, therefore, fortunate to count on antimicrobial drugs to eliminate harmful pathogens. Read more →
Bdellovibrio–Prey Interactions
Noteworthy — The environmental bacterium Bdellovibrio bacteriovorus is unique in its capacity to prey and feed on other bacteria. This predatory behavior involves attaching and entering prey cells to consume and grow on cytoplasmic macromolecules, eventually lysing the host. But how do these bacterial predators recognize and invade their prey? Read more →
Defining Life with Aristotle
by Chelsi Cassilly and Eric Bodlak — What is life? Initially, it seems like a simple question. The immediate response is often to compare and contrast the many things we encounter daily that are animate and inanimate. Yet this question becomes harder the longer you sit with it. Because life on this planet – that is, life as we know it – includes microbial life... Read more →
Did organs precede organisms in the dawn of life?
by Fernando Baquero — We are commemorating the centennial of the first significant scientific hypothesis aimed at understanding the origin of life, published in 1924 by Alexander Ivánovich Oparin (1894-1980). The implicit message in this wonderful-to-read publication, but not expressed as such in the text, is that life arises in a kind of primordial soup of organic and inorganic molecules dissolved in hot water. Read more →
Pseudouridine, antibiotics, and blue
by Janie — Pseudouridine, an isomer of uridine, is perhaps now most widely known for its critical role in the success of the COVID-19 mRNA vaccines. Three years ago on STC, Roberto wrote an appreciative note about this key feature of the vaccines, the N1-methylpseudouridine that acts a bit like an invisibility cloak... Read more →
E. coli Proto-Genes
by Roberto — How do bacteria come up with new genes? I intentionally did not use the phrase "acquire new genes" because, as most STC readers might know, horizontal gene transfer is likely the most frequent way new genes end up in a bacterium's genome. What I ask now is different. After more than four billion years of evolution, are bacteria still giving birth to new genes 'de novo' ? Read more →
A lesson from the comb jelly, deep-sea bacteria, and some obliging E. coli on how to thrive under pressure
by Janie — I sometimes google "Small Things Considered + a biological term of choice" looking for older articles, to see if any paradigms have changed in the span of a decade or so. In doing so, I came across this post from 2010 on plasmalogens, membrane lipids with an ether bond linking the glycerol... Read more →
Thoughts on O-Antigen Variation
by Roberto — The O-side chains of lipopolysaccharides (LPS), the outer most feature of most Gram-negative's outer membrane, are highly variable in terms of their chain length and chemical composition. In my last post, I described how the O-side chain of some bacterial strains serve as a settlement and metamorphosis cue for a marine invertebrate. My thoughts immediately took me to this question: What was the early evolutionary history of O-side chain variability? Read more →