Podcasts about planctomycetes

This episode: A newly discovered species of bacteria consumes other bacteria as prey by engulfing them! Download Episode (8.7 MB, 12.6 minutes) Show notes: Microbe of the episode: SARS-CoV-2! This is the coronavirus responsible for COVID-19, the current pandemic. For more up-to-date information, please refer to the American Society for Microbiology, This Week in Virology, and other reputable sources. Stay healthy! Takeaways There are bacteria living almost every different lifestyle you can think of, including predatory, preying on other bacteria. Since bacterial cells are usually quite rigid, bacterial predators usually consume others either by burrowing inside them or digesting them from outside, rather than engulfing prey like eukaryotes often do. The study here discovers a new kind of bacteria, in the group called Planctomycetes, known for having unusually flexible cells and internal compartments like eukaryotes. This new species does engulf its prey, including bacteria and even tiny algae, and digests them inside itself. It possesses multiple adaptations that suit it for this lifestyle. Journal Paper: Shiratori T, Suzuki S, Kakizawa Y, Ishida K. 2019. Phagocytosis-like cell engulfment by a planctomycete bacterium. Nat Commun 10:1–11. Other interesting stories: Engineering a common industrial yeast strain to fix carbon dioxide (paper) Lake microbes convert microplastics into essential fatty acids   Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening! Subscribe: Apple Podcasts, Google Podcasts, Android, or RSS. Support the show at Patreon, or check out the show at Twitter or Facebook.

Bacteria necessitate multiple signal transduction systems to sense the ever-changing environments and mediate the cellular response accordingly. The major bacterial signal transduction systems are one-component system (1CS), two-component system (2CS) and extracytoplasmic function (ECF) σ factor. Compared to 1CSs and 2CSs, ECF σ factors have only been identified much later and therefore the knowledge about their molecular mechanisms and physiological roles is less profound. This thesis mainly focuses on the study of ECF σ factors from the bacterial phyla, Planctomycetes and Actinobacteria.

Bacteria necessitate multiple signal transduction systems to sense the ever-changing environments and mediate the cellular response accordingly. The major bacterial signal transduction systems are one-component system (1CS), two-component system (2CS) and extracytoplasmic function (ECF) σ factor. Compared to 1CSs and 2CSs, ECF σ factors have only been identified much later and therefore the knowledge about their molecular mechanisms and physiological roles is less profound. This thesis mainly focuses on the study of ECF σ factors from the bacterial phyla, Planctomycetes and Actinobacteria.

Soils harbor highly diverse bacterial communities. It is still poorly understood whether functional redundancy or a multitude of ecological niche modify the abundance and community composition of bacteria in soil. Understanding why soil microorganisms are so diverse and which factors control their community composition is of importance because they are essential for maintaining ecosystem processes and functions. Alterations of biotic or abiotic factors as results of natural or anthropogenic disturbances are known to influence soil bacterial diversity. However, the relation of those factors on microbial diversity is not well understood. This work examined effects of several environmental factors, specifically the presence of higher plant species, water content, land use, and soil properties, on bacterial diversity by employing two different soil sources. The reproducibility of bacterial community composition in manipulated soil was analyzed by use of group-specific phylogenetic PCR-DGGE fingerprinting. Soils were taken from lysimeters that had been planted with four different types of plant communities and the water content was adjusted. The composition of Alphaproteobacteria, Betaproteobacteria, Bacteroidetes, Chloroflexi, Plancto-mycetes, and Verrucomicrobia populations were clearly different from soils without plants compared to that of populations in planted soils. In contrast, the composition of Acidobacteria, Actinobacteria, Archaea, and Firmicutes populations did not influenced by the environmental factors tested. No clear influence of plant diversity and water content could be observed. The reproducibility of bacterial composition associated with the absence or presence of plants was true, even for the low-abundance phylotypes as shown by phylotype beta10 representing up to 0.18% of all bacterial cells in planted soils compared to 0.017% in those unplanted. A high throughput cultivation approach was performed by employing the MicroDrop and the soil slurry dilution techniques. Soil-solution-equivalent medium (pH 7.0) supplemented with artificial root exudates, yeast extract, and inducers was utilized. From 217 cultures obtained, isolate byr23-80 showing the same sequence with phylotype beta10 was recovered and studied in detail as this phylotype displayed a distinct response towards the presence of higher plant species and its sequence affiliated with uncultured bacteria, so far. The strain exhibited high physiological flexibility and was capable of utilizing major constituents of root exudates. A polyphasic taxonomic analysis and DNA-DNA hybridization data supported an assignment of strain byr23-80 as a novel species to the genus Massilia within the family Oxalobacteraceae of the subphylum Betaproteobacteria, for which the name Massilia brevitalea is proposed. Effects of land use and soil properties on the bacterial diversity and activity were determined by employing natural soil from the Kavango region, Namibia. Soil properties in fact controlled the soil respiration rates rather than land use as pristine dark loam soil had remarkably higher respiration rate than pristine sand soil. Exoenzyme activities greatly varied among sites, but did not show a clear correlation to one of the two factors. The quantitative PCR identified Acidobacteria and Actinobacteria as the most abundant phyla about of 30 and 20% of all Bacteria, respectively. Alphaproteobacteria, Bacteroidetes, and Planctomycetes accounted for below 10%, whereas Betaproteobacteria, Chloroflexi, and Firmicutes represented less than 1%. Clone library of 16S rRNA genes from pristine dark loam soil revealed a high bacterial diversity with an estimated number of about 5600 phylotypes. The PCR-DGGE fingerprinting of Acidobacteria and Actinobacteria did only show minor differences in composition of the bacterial communities among sampling sites. This study suggests that the bacterial species compositions in soil are determined to a significant extent by abiotic and biotic factors, rather than by mere chance, thereby reflecting a multitude of distinct ecological niches.