Warmer temperature increases metabolic processes and cell division but lowers protein synthesis in soil microbes
Responses of soil microbes to global warming are important to conclude future soil-climate feedback; however, it is not well understood.
Researchers investigated microbial physiological responses to medium-term and long-term subarctic grassland soil warming of +6°C.
Medium-term is 8 years and long-term is more than 50 years.
Researchers observed indications for a community-wide increase in central metabolic pathways and cellular replication.
Additionally, researchers observed a reduction of bacterial protein biosynthesis machinery in the elevated temperature soils which occur at the same time with lower microbial biomass, RNA, and substrate content.
Researchers concluded that the increased reaction rates at higher temperatures and the reduction of substrates triggered ribosome reduction.
The ribosome is a macromolecular complex that carries protein synthesis.
Another study involving short-term warming experiment of +6°C at 6 weeks further supported the conclusion.
The reduction of protein biosynthesis machinery frees up energy and matter which allows soil microbes to continue a high metabolic process and cellular division even after years of increasing temperature.
 De Vos, Lobke; Van de Voorde, Babs; Van Daele, Lenny; Dubruel, Peter; Van Vlierberghe, Sandra (December 2021). “Poly(alkylene terephthalate)s: From current developments in synthetic strategies towards applications”. European Polymer Journal. 161: 110840. https://doi.org/10.1016/j.eurpolymj.2021.110840
Bacteria “vaccinate” themselves to protect from viral infection
Prokaryotes have developed various defense mechanisms against viruses.
CRISPR is one of the processes that protect prokaryotic organisms from viruses.
CRISPR allows bacteria to remember DNA from invading viruses and chop off viral DNA to stop the infection.
Researchers studied the relationship between two of the popular prokaryotic immune systems namely CRISPR and restriction-modification.
Both mechanisms utilize enzymes that cut a specific DNA sequence of the invading virus; however, CRISPR nucleases are programmed with phage-derived spacer sequences which are integrated into the CRISPR genetic position upon infection.
Researchers found restriction enzymes help in providing short-term defense which can be quickly overcome through methylation of the viral genome.
Methylation is a process by which a methyl group is added to DNA and inhibits gene expression.
Restriction enzymes can cut short DNA sequences so bacteria can utilize these DNA sequences soon after viral infection starts.
However, few other cells acquired spacer sequences from the cleavage site which moderate a strong type II-A CRISPR-Cas immune mechanism against the methylated virus.
This mechanism reminds us of the eukaryotic immune response in which the innate immunity provides a first short-term line of defense and also activates a second but stronger adaptive immune response.
Maguin, P., Varble, A., Modell, J. W., & Marraffini, L. A. (2022). Cleavage of viral DNA by restriction endonucleases stimulates the type II CRISPR-Cas immune response. Molecular cell, 82(5), 907–919.e7. https://doi.org/10.1016/j.molcel.2022.01.012
Microbes work together to form drug-tolerant communities
Microbial communities comprise cells with different metabolic capacities and may include auxotrophs.
Auxotroph is an organism, usually a mutant bacteria, that cannot synthesize substances needed for its growth and metabolism.
Researchers analyzed amino acid biosynthesis pathways in auxotroph from microbiome data of more than 12,000 natural microbial communities.
Researchers also examined the auxotrophic-prototrophic interactions in yeast communities.
Researchers discovered a mechanism that links auxotrophs to an increase in metabolic interactions and anti-microbial drug tolerance.
The auxotrophs have been observed to obtain altered metabolic flux distribution, export more metabolites, and as a result, enrich the community in metabolites.
Metabolites are intermediate or end-product substances produced by metabolism.
These capabilities observed from auxotrophs may be the consequence of the metabolic adaptations required to use specific metabolites.
Additionally, researchers observed that the increased metabolite exportation was correlated with the decrease in intracellular drug concentrations.
The reduction of intracellular drug concentration allows microbes to grow even at drug levels above minimal inhibitory concentrations.
Minimal inhibitory concentration is the lowest concentration of drugs that can inhibit the growth of bacteria.
Researchers demonstrated that an antifungal compound called azoles did not significantly eliminate yeast cells that use metabolites from a metabolically-enriched environment.
The results describe a mechanism that enhances our understanding of why cells are more tolerant to drug exposure when they metabolically interact.
Yu, J.S.L., Correia-Melo, C., Zorrilla, F. et al. Microbial communities form rich extracellular metabolomes that foster metabolic interactions and promote drug tolerance. Nat Microbiol (2022). https://doi.org/10.1038/s41564-022-01072-5
Blind cavefishes have larger red blood cells to survive in a low-oxygen habitat
Animals that thrive in extreme environments can be used to study adaptive evolution in response to different pressures.
One example of these pressures is reduced oxygen levels.
Environments with low oxygen are commonly found in subterranean and high-altitude regions.
Animals living in caves must also deal with starvation and the dark environment, both of which have been thoroughly studied as an important factor driving the evolution of traits related to caves.
Hypoxia, the state in which oxygen is lacking at the tissue level, does not receive much attention as an environmental pressure.
Researchers examined adaptive characteristics evolving in Mexican tetra, also known as the blind cavefish.
Mexican tetra is notable for having no eyes or pigment.
Mexican tetra has two forms, surface-dwelling, and cave-dwelling.
Additionally, researchers also identified other responses to hypoxia with the help of many natural and independently-colonized cave populations together with closely-related surface animals of the same species.
Researchers focused on a very important oxygen-carrier molecule called hemoglobin.
Researchers discovered that numerous cave populations had higher hemoglobin concentration which was proportional to the increase in red blood cell size of the cave-dwelling form compared to the surface-dwelling fish.
Interestingly, both cave and surface-dwelling fishes had similar concentrations of red blood cells which suggest that higher hemoglobin levels were not due to the rise of red blood cell count.
Researchers speculated that the larger-sized red blood cells in cavefish contain more hemoglobin.
The study reinforces the idea that cavefish have adapted to low oxygen environments through changes in both red blood cell size and hemoglobin production.
Boggs, T.E., Friedman, J.S. & Gross, J.B. Alterations to cavefish red blood cells provide evidence of adaptation to reduced subterranean oxygen. Sci Rep 12, 3735 (2022). https://doi.org/10.1038/s41598-022-07619-0
 Keene, A.; Yoshizawa, M.; McGaugh, S. (2016). Biology and Evolution of the Mexican Cavefish. pp. 68–69, 77–87. ISBN978-0-12-802148-4
New species of cephalopod with ten arms discovered in Montana
Vampyropods are soft-bodied cephalopods that have eight arms and an internalized chitinous shell.
Researchers discovered an exceptionally well-preserved vampyropod from the Carboniferous Bear Gulch Lagerstätte of Montana in the United States.
The newly discovered vampyropod was named Syllipsimopodi bideni gen. et sp. nov.
The specimen has an internalized shell and ten arms with suckers arranged in two rows.
It is the only known vampyropod to retain the ten arms from its ancestor.
Syllipsimopodi is the oldest conclusive vampyropod and crown coleoid which pushes back this animal group’s fossil record by about 82 million years.
Researchers showed that Syllipsimopodi is the earliest-diverging known vampyropod.
This idea disputes the common hypothesis that vampyropods descended from Phragmoteuthid belemnoid of the Triassic period.
As early as the Mississippian, vampyropods were characterized by the loss of the chambered phragmocone and primordial rostrum.
Phragmocone is the chambered portion of the cephalopod’s shell.
Evidence suggests that the specimen may have elongated arms which when combined with certain structures such as the terminal fins, shows that the earliest vampyropods appeared to be similar to extant squids.
Whalen, C.D., Landman, N.H. Fossil coleoid cephalopod from the Mississippian Bear Gulch Lagerstätte sheds light on early vampyropod evolution. Nat Commun 13, 1107 (2022). https://doi.org/10.1038/s41467-022-28333-5
 American Museum of Natural History. (2022, March 8). New species of extinct vampire-squid-like cephalopod is the first of its kind with 10 functional arms: Description of exceptionally preserved fossil pushes back age of Vampyropoda by nearly 82 million years. ScienceDaily. Retrieved March 8, 2022 from www.sciencedaily.com/releases/2022/03/220308115650.htm