Da Bom: Best of Microbiology News Summer 2021

Extremophiles & Space ‘Crobes: Cyanobacteria

Possible link between Earth’s rotation rate and oxygenation - J. M. Klatt et. al. in Nature Geoscience

• It is believed that extremophiles like cyanobacteria were responsible for converting the Earth's atmosphere to be filled with oxygen, a process that took around 2 billion years called the great oxygenation event.

• Cyanobacteria use light energy and conduct photosynthesis to create organic compounds with O2 as a by-product.

• These microbes did not do it themselves, the length of the day may have been a big factor. Earth's rotation is one full cycle every 24 hours, but it was much faster when the Earth was younger and may have been as short as 6 hours. It is thought that the slowing of the earth's rotation is due to tidal friction or the friction caused by the tug of the moon's gravity on earth.

• The Scientific team in this study looked at cyanobacteria at the bottom of the Lake Huron sinkhole where the water is low in O2 and high in sulfur, so the environment and microbes were good representations of the conditions on Earth at the time.

• The team found that day lengths affected the amount of oxygen being produced; the longer the day the more O2 produced and the reverse was true for a shorter daylength

• The cyanobacteria in the lake are also in a sort of dance with sulfur-oxidizing bacteria. In the morning and evening, the sulfur bacteria cover the cyanobacteria and prevent photosynthesis; but when the light gets too intense, the sulfur bacteria will go deeper into the sinkhole allowing the cyanobacteria to conduct photosynthesis. In shorter days, the sulfur-producing bacteria have a greater effect in limiting the cyanobacteria’s ability to photosynthesize

• The scientists were also able to model and show that day length shapes O2 release from these bacterial mats.

• So it may be that there are many factors that led to the rise of oxygen on earth.

Food & Agriculture Microbiology: Fermented Food and Bacteriophage

Fermented food fighting for us- Part I - From Microbites. This article is a little mini-review blog post that incorporates facts from 13 different articles. So if you’d like to review any of the articles you can find them on the Microbites site.

• Fermented foods are created when raw food products are introduced to a culture of microorganisms. Think yogurt, kimchi, and sauerkraut.

• Most cultures that are used for fermented foods are called Lactic acid bacteria (LAB). Many of these microbes may sound familiar to you if you’ve ever looked at the strains in your yogurt and read the label on a probiotic. These include microbes like lactobacilli, lactococci, enterococci, and streptococci.

• There might also be bad microbes mixed in here. Great attention to the sterility of the process is important as the cultures themselves may not always be safe and can be infected with bacteriophages.

• Bacteriophages are viruses that specifically infect bacteria. They can hijack the cellular machinery and energy of a bacteria cell to replicate themselves. Bacteriophages are frequent culprits of fermentation failure- leading to losses of batches.

• Not only do some bacteriophages inflict damage in the fermentation process, but others utilize LAB cultures as a trojan horses. This is important as viruses do not survive well outside of a host. Both hepatitis A and E, norovirus, and rotavirus sneakily attack via fermented foods or other fecal contaminated foods.

• Luckily in the case of COVID-19, like most respiratory viruses, the lipid bilayer of that virus was easily disrupted by the salt, low acidity, and temperature during fermentation

• Bacteriophages also have benefits. Not only do bacteriophages positively impact the culture of fermented foods themselves, but they can also influence the host’s microbiome as well. First, they might protect the host from a pathogenic microbe or infect healthy microbes and change their behavior to be beneficial.

• Many lactic acid bacteria (LAB) used in the food fermentation process are classified as probiotics. Many probiotic products exist out there, but few act as "cure-all" for any digestive discomforts and for diseases. However, incorporating probiotic-rich foods, like fermented foods, has been shown to have a beneficial effect on one’s overall health because of the bioactive compounds that they produce.

• In conclusion, not only do fermented foods add a delicious dimension to your food but their multi-faceted abilities to improve overall health should convince you to incorporate them into your diet!

Environmental & Marine Microbiology: When Did Plant Come To Land?

Discovered: Fossilized Spores Suggestive of early land Plants - Paul K. Strother and Clinton Foster

• There has been a gap in the understanding of when plants adapted to living on land and how that may have happened.

• A variety of fossilized plant spores have been found in rocks from Western Australia that date from the early Ordovician era—approximately 480 million years ago.

• The rock samples had been drilled from the Canning basin in Western Australia and prepared as slides back in 1958 as part of Australia’s search for oil

• Some of the spores may have belonged to early forms of land-dwelling algae, from which other land plants are thought to have originated.

• Macrofossils of the oldest known plants are 425 million years old and molecular clock estimates, which is partially based on genetic mutation rates, but the first land plants 505 million years ago, it is possible that we have not found fossil evidence of plants that old is their structure may have been too soft to preserve. Spores, on the other hand, have tough cell walls and are more easily able to be fossilized so they can be used as a proxy for plants

• In fact, it has long been hypothesized that spores were one of the earliest plant adaptations to life on land, says Strother. Just as the egg preceded the chicken, evolutionarily speaking, so spores preceded sporophytes, the spore-producing plant structures that can take the form of, say, fruiting bodies of moss, fronds of ferns, trees, and so on.

• The findings not only push back the fossil record of land plants another 20 million years, says paleobotanist Patricia Gensel of the University of North Carolina who was not involved in the research, they also add weight to the idea that the spore-like fossils belonged to land-based algae. “It’s supporting the idea that there were some land-dwelling algae and early [land] plants that lived together,” she says.

Pathogen Profiles & Medical Microbiology: The Dark Side Of Staphylococcus Epidermidis

A simple Switch from Friend to Foe. - From Microbites Written By Julie Starkey

• An opportunistic pathogen can switch from harmless friends to infectious foes. We want to know why using the case of Staphylococcus epidermidis.

• Staphylococcus epidermidis is a skin opportunistic bacteria that can switch and cause infectious diseases like sepsis in hospitals and resist antibiotics.

• The bacterial species has a complex sugar molecule called wall teichoic acid (WTA) that is present in the bacterial cell wall and plays a role in their shape and interaction with their host.

• Could we produce Staphylococcal vaccines that target RboP-WTA without disturbing our normal microflora?

Biotech & Microbial Products : Microbial Protein

Photovoltaic-driven microbial protein production can use land and sunlight more efficiently than conventional crops - Dorian Leger, Silvio Matassa, Elad Noor, Alon Shepon, Ron Milo, and Arren Bar-Even

• Right now about half of the arable land in the world is already devoted to agriculture and 690 million people went hungry in 2019 according to the State of Food Security and Nutrition in the World report. When you add this to the growing population, which is now expected to exceed 10 billion by 2050, we are setting ourselves up for an extreme food crisis within the next 3 decades.

• Arren Bar-Even and his team evaluated one solution called photovoltaic-driven single-cell protein which is produced by microbial biomass. They created a model that compared conventional crops systems to photovoltaic-driven Single-celled protein systems. Specifically, they analyzed photovoltaic electricity generation, direct air capture of carbon dioxide, electrosynthesis of an electron donor and/or carbon source for microbial growth (hydrogen, formate, or methanol), microbial cultivation, and the processing of biomass and proteins.

• They break it down into four steps. In step 1, solar panels are used to capture solar energy which is converted to electricity. In step two the electrical energy is converted into chemical energy (an electron donor). Step three microbes use that chemical energy to produce more biomass. Step four filter out the junk and purify the proteins.

• Their conclusions are kind of mind-blowing. Per unit of land, they found the microbial biomass method could produce 10x the amount of protein and 2x the calorie density compared to staple crops like soybean.

• Soybean can produce 1.1 tons of protein per year per hectare which authors estimated could feed 40 people on a daily protein consumption of 80g of protein

• Take that same piece of land and now optimize it for a photovoltaic-driven single-cell protein system and you can now produce 15 tons of protein using the same amount of land. Feeding 520 people! 10X more than the soybean treatment!

Those were our picks! What do you think is the greatest microbiology News for the summer? Let us know in a comment below!

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