Ultrasmall-celled “
Ca.
Patescibacteria” have been estimated to account for one-quarter of the total microbial diversity on Earth, the parasitic lifestyle of which may exert a profound control on the overall microbial population size of the local ecosystems. However, their diversity and metabolic functions in marine sediments, one of the largest yet understudied ecosystems on Earth, remain virtually uncharacterized.
Chlorinated ethenes are risk drivers at many contaminated sites, and current bioremediation efforts focus on organohalide-respiring
Dehalococcoides mccartyi
strains to achieve detoxification. We isolated and characterized the first non-
Dehalococcoides
bacterium, “
Candidatus
Dehalogenimonas etheniformans” strain GP, capable of metabolic reductive dechlorination of TCE, all DCE isomers, and VC to environmentally benign ethene.
Epibiotic bacteria are known to live on and off bacterial cells. Here, we describe the ultramicrobacterial anaerobic epibiont OP3 LiM living on
Archaea
and
Bacteria
.
Among endosymbiotic bacterial lineages, few are as intensely studied as
Rickettsiales
, which include the causative agents of spotted fever, typhus, and anaplasmosis. However, an important subgroup called “
Candidatus
Midichloriaceae” receives little attention despite accounting for a third of the diversity of
Rickettsiales
and harboring a wide range of bacteria with unique features, like the ability to infect mitochondria.
Amycolatopsis coloradensis ATCC 53629 is the producer of the glycopeptide antibiotic avoparcin. While setting up the production of the avoparcin complex, in view of its use as analytical standard, we uncovered the production of a to-date not described ristosamynil-avoparcin. Ristosamynil-avoparcin is produced together with α- and β-avoparcin (overall indicated as the avoparcin complex). Selection of one high producer morphological variant within the A. coloradensis population, together with the use of a new fermentation medium, allowed to increase productivity of the avoparcin complex up to 9 g/L in flask fermentations. The selected high producer displayed a non-spore forming phenotype. All the selected phenotypes, as well as the original unselected population, displayed invariably the ability to produce a complex rich in ristosamynil-avoparcin. This suggested that the original strain deposited was not conforming to the description or that long term storage of the lyovials has selected mutants from the original population.
Biological foaming or scumming is a sludge separation problem that has become the subject of major concern for long-term stable activated sludge operation in decades. Biological foaming was considered induced by foaming bacteria.
A wide array of archaea populate Earth’s extreme environments; therefore, they may play important roles in mediating biogeochemical processes such as iron and sulfur cycling. However, our knowledge of archaeal biology and evolution is still limited considering that the majority of the archaeal diversity is uncultured.
The bilayer formed by membrane lipids serves as the containment unit for living microbial cells. In the marine environment, it has been firmly established that phytoplankton and heterotrophic bacteria can substitute phospholipids with nonphosphorus sugar-containing glycoglycerolipids in response to phosphorus limitation.
The exploration of deep marine sediments has unearthed many new lineages of microbes. The finding of this novel phylum of Asgard archaea is important, since understanding the diversity and evolution of Asgard archaea may inform also about the evolution of eukaryotic cells. The comparison of metabolic potentials of the Asgard archaea can help inform about selective pressures the lineages have faced during evolution.