Here is a list of our posts from the last half year − which felt significantly longer than usual, right? − briefly annotated.
Symbioses and Other Friendships
Biofilms by Insect Endosymbionts Janie is fond of biofilms (and who isn't?). She figures that bacterial endosymbionts of insects make them too (and why not?).
A Short History of Yogurt Add a dollop of honey to yogurt and, if you believe Roberto, you have the "food of the gods." And, on top of that, you witness therein a lovely symbiosis between two lactic acid bacteria, one producing amino acids needed by the other, the other providing its partner with formate and carbon dioxide. Divine indeed.
Having the bow and arrow might not be enough... Natália Drebes Dörr, Ph.D. student in the lab of Melanie Blokesch in Lausanne, Switzerland, tells us that the daily challenges in the life of microscopic organisms are not that different from those experienced by cheetahs and gazelles in the savanna.
Streptomyces spores taking a ride... Christoph tells us that nonnmotile Streptomyces spores move along by clinging to motile Bacillus subtilis. They hitch a ride by sticking to its flagella. Whoopee!
Underground Highways Roberto comes up with what sounds like the opposite story, fungi helping bacteria to travel around. They swim along the liquid film that is formed outside the hyphae. The bacteria pay a toll, supplying the fungi with needed thiamine.
Exploration, Streptomyces-style More about motility, Roberto tells the strange story of the usual immobile Streptomyces moving around an agar plate (exploratory motility) when in the presence of the equally immobile common yeast, S. cerevisiae. What gives? It seems that the yeast does this by consuming glucose, thus demanding that the Streptomyces move around in quest of food. And there is even more to it…
Let Smell Guide You Did you know that geosmin, the substance that smells like fresh soil, can be detected by humans at amazingly low concentrations? It's made by actinomycetes during sporulation and attracts springtails, besides humans. The spores attach to the insects and are thus dispersed all over the map. Roberto explains.
Pathogens and Other Lesser Friends
The Type VI Secretion System A fine review of this exciting system by Hernandes, Gallegos-Monterrosa, and Coulthurst.
A Novel Way to Kill Your Neighbor Use type VI secretion to inject an enzyme that makes ppApp and pppApp and thus deprive the recipient of its required ATP. Elio calls this murder.
The Streptococcal Wolf in Sheep's Clothing Janie describes a novel exciting story. In her words: "Group A Strep co-opts pieces of red blood cell membranes to camouflage itself from the immune system, using a particularly tricky, sticky protein." Clever, eh?
Family Feud: Commensal vs. Pathogenic Neisseria Camille Brzechffa, a recent graduate from Occidental College, tells us that a commensal neisseria, N. elongata, kills the pathogenic N. gonorrhoeae via secreted DNA. The degree of methylation is crucial.
These Bacteria are Out of This World: Human Pathogens on the International Space Station Occidental College graduate Rachel Sidebottom virtually visits the International Space Station in quest of bacterial pathogens that may lurk in its corners. She reports that mainly Gram positives make biofilms on common steel surface in the stations. And many are antibiotic resistant to boot. Pay heed, astronauts!
Spy Gadgets Janie tells us of a protein of Gram positives, FbaB, that facilitates adhesion of the bacteria to host cells via their pili. Superglue!
Protect Your Genes and Express Yourself Dps, a protein discovered in Roberto's lab at Harvard, protects DNA from damage by compacting it. In so doing, it makes it inaccessible to some other proteins. Recent work by Anne Meyer suggests that this happens because the Dps-DNA complexes are a "liquid crystal" that allows certain proteins but not others to enter it. Read on!
Getting to grips with the intangible What is the "mesh size" of a nucleoid? Xiang et al. found it out by using a fluorescent-labeled protein that self assembles into "nanocages" that freely localize throughout the cytoplasm. But, if large enough (>50 nm in diameter), they do not enter the nucleoid. Thus, the holes in the mesh of the nucleoid are about 50 nm. Christoph discusses this....
The Cake-Cutting Problem in the Archaeal World Kanika Khanna, a recent Ph.D. from UCSD, discusses how two pleomorphic Archaea place their division machinery via 'Turing patterns' (which you better look up here.)
A Change in the Plan of Construction Phyllody is when a flower is replaced by a leafy structure. It is sometimes caused by Phytoplasma, mycoplasma relatives that require an insect vector for transmission. Roberto explains the details of how this works.
Fucoidans, A Feast for Few Janie tells us about complex seaweed polysaccharides that are quite resistant to microbial degradation. But the little known Lentimonas, a member of the Verrucomicrobia, can do it, using a large array of plasmid-encoded enzymes, 284 no less. They snip off fucose, the bacterium's favorite sugar, from the ends. As Janie says, "microbes will play the cards they've been dealt."
Alcanivorax, an efficient cleaner of our oceans Joseph A. Christie-Oleza and Vinko Zadjelovic from the Universitat de les Illes Balears, Spain, share their fascination with this humble marine bacterium.
Sticking together «...wie Pech und Schwefel» Christoph introduces a "Tweetorial" by Austrian microbiologist Alexander Loy on the ubiquitous and abundant microbial nutrient, sulfoquinovose. Never heard of it? Here's your chance to learn about it.
History, Then and Now
The recent ASM President Robin Patel Speaks: "ASM Touches So Many, At So Many Levels." She tells us that her presidency "has been an amazing and fulfilling journey, and a great way to serve science and humanity."
Remembering a Remarkable Man Roberto sings the praises of Harold Ames, the first (and so far only) Black chair of the microbiology department at Harvard Medical School and beloved by all who knew him. What a special human being!
An Enlightening Evening to Remember David Westenberg of the Missouri University of Science and Technology sings the praises of the famed Microbial Diversity course at the Marine Biological Laboratory in Woods Hole, MA. His class repeated the classic Volta experiment – collecting methane gas in a vessel and igniting it. Enlightening indeed!
The Dead Sea Scrolls come under the Genomic 'Scope Elio takes delight in describing how studying the DNA of the pelts on which the scrolls were written sheds light on their origin.
Wonders Of A Pool Tuffen West’s words illustrates the pleasures of a Victorian naturalist in the field.
Putting Life on Earth in Perspective Roberto tells us about a lecture he gave in Heidelberg’s European Molecular Biology Laboratory (EMBL). Among other things, he says he told them: "Global phytoplankton has declined dramatically over the past century and the diversity of the intestinal microbiota of "westernized" humans is about half that found in previously uncontacted Amerindians. Is the situation bleak beyond repair? He says: "I don't think so, but then I consider myself an optimist."
Elio's Memoirs In 20 chapters, mostly readable, Elio describes his life in Italy, Ecuador, the United States, and Denmark.
Christoph recommends online material colelctions of use to teachers of microbiology.
Where have all the protons gone? Roberto wonders.
Long Before Fleming Yes, others found earlier that molds inhibit bacteria. Fleming made something out of it, says Roberto.
Of Terms of Biology
Trans-Translation by John McCutcheon, Janie and Christoph
Dysbiosis by Elio
RNA Thermometer by Christoph
Purifying Selection by Elio
A Whiff of Taxonomy
The Apicomplexa by Elio