Small Things Considered

The COVID-19 Virus by the Numbers

by Elio — The trio of Yinon Bar-On, Rob Phillips, and Ron Milo, here augmented by Avi Flamholz, have done it again. In the past, they presented us the astounding numbers for the distribution of biomass on this planet, no less. We highlighted this seminal contribution to our understanding of the living world... Read more →

Virus. ...simply a piece of bad news wrapped up in protein, really ?

by Christoph — In my prior post, I answered the question "are viruses alive?" with a firm: no. That was the short answer, but there is also a long answer... and it's long because it's complicated. Read more →

Virus? ...simply a piece of bad news wrapped up in protein.

by Christoph — In the middle of the first major pandemic of my lifetime I feel the need, as a microbiologist, to make occasional contributions that may help individuals and society approach the pandemic in a reasonably informed way. Today, I'd like to contribute with a small dose of 'microbial literacy,' as called for by Ken Timmis and colleagues... Read more →

Little things matter, in both virology and your PhD

by Shuxuan Zheng — Blaise Pascal said that "Little things console us because little things afflict us." In the time of CO­VID-19, Pascal's words have never been more prescient. Viruses – those little things behind the global microbiological threat – demand not only our fear but also our respect. Read more →

Three to Tango

by Elio — How many symbioses that involve three partners can you think of? Surely, not many. But here is one, involving a pathogenic fungus, a bacterium, and a fungal virus. Read more →

Of Terms in Biology: Contagion

by Elio — A much used term nowadays, "con­ta­gi­on" or in ad­jec­tive form, "con­ta­gi­ous," is de­rived from La­tin 'con­tā­giō' (touch­ing, con­tact, con­ta­gi­on) re­la­ted to 'con­tin­gō' (touch clo­se­ly). In its ori­gi­nal mean­ing, the term re­fer­red so­le­ly to a dis­ease trans­mis­sible by di­rect phy­si­cal con­tact. Now­adays, its mean­ing has been broad­ened to in­clude all com­mu­ni­cable or in­fect­ious dis­ea­ses. As the Wi­ki­pe­dia says: "Of­ten the word... Read more →

Where Do Phages of Atypical Bacteria Come From? A Snippet.

by Elio — Some time ago, a piece in this blog dealt with the com­ple­xi­ties of the Gram stain. In brief, it said: "In a simp­ler world, all bac­te­ria with a single mem­brane, the mono­derms, would be Gram-po­si­tive, all those with two (the di­derms), Gram-ne­ga­tive..." Hah! Were it that simple! Each of these groups... Read more →

Flagella By the Tail

by Elio — We now know that the site of delivery of the phage DNA is not the flagellar filament but rather a region near its base. When the phage reaches it, it can deliver its DNA into the host, as demonstrated by the presence of empty (DNA-less) phage heads at the base of the flagellum. The whole thing takes less than 5 minutes. Read more →

Will the real phage lambda please stand up?

by Nicholas Redmond — Phage infection of a bacterial cell typically begins when the phage’s tail fibers bind a receptor on the host cell, allowing for the ejection of genetic material. At this point, either the lytic or lysogenic cycle begins. Read more →

Secondary Metabolites

by Andy Bodnar, Michelle Prieto, and Carleen Villarreal — The war between bacteria and phages has been waging for eons longer than humans have existed. Consequently, many bacteria have developed novel and unique ways for defending themselves against these foreign invaders. Some change their surface proteins to prevent detection, like changing a lock on a door. Others give their own lives, initiating... Read more →