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Simple Summary: The air microbiome is one of the most poorly characterized microbial communities of environmental objects. It has been suggested that leaves are indicators of air quality. In the present work, the taxonomic and functional diversity of bacterial and fungal communities, PAHs, and metal contents in PM100 of leaves and PM10 of air collected from two zones with different levels of anthropogenic pollution were compared. Dust particles found on the surface of leaves and air filters were also compared using scanning electron microscopy. Our data showed that air pollution had a greater effect on phylloplane bacterial communities. The effect of air pollution on bacterial communities could facilitate their use as indicators for monitoring atmospheric conditions. At the same time, bacterial organisms are performers whose role in biotechnological methods of air purification is inevitably important. Identifying the relationship between the microbiomes of urban dust particles from different biotopes is important because the state of microorganisms can be used to assess the quality of the environment. The aim of this work was to determine the distribution and interaction patterns of microorganisms of dust particles in the air and on leaf surfaces. Metabarcoding of bacterial and fungal communities, PAH, and metal content analyses and electron microscopy were used in this work. The results obtained allowed us to characterise the biological and chemical components of the dust particles. Some bacterial and fungal genera were correlated with benzanthracene, fluoranthene, and Cu, Ni, Co, Zn, and Mn contents. Bacterial communities were found to be more sensitive to all the pollutants studied. PM10 microbial communities circulated between biotopes and study areas due to air flows, as evidenced by the presence of similar ASVs in fungi and bacteria. The results could help to understand the effects of climate change and anthropogenic activities. [ABSTRACT FROM AUTHOR]

Simple Summary: Air pollution has been identified as a contributing factor to increasing antibiotic-resistant bacteria in the microbiome of dust particles. The aim of the study was to structurally and functionally characterise the microbial communities of dust particles in urban ecosystems of Moscow and to compare the prevalence of predicted resistome modules and culturable antibiotic-resistant bacteria in the microbiomes. The present study revealed a higher prevalence of antibiotic-resistant bacteria in the microbiomes of dust particles sampled in the most polluted functional zones of Moscow. Furthermore, antibiotic resistance was a more diverse functional characteristic of the microbial communities of airborne particles. Urban dust samples were collected in Moscow (Russia) in June 2021. The samples were collected in three functional zones of Moscow (traffic, residential, and recreational) and included air microparticles, leaf dust, and paved dust. Data on the taxonomic composition of bacterial communities were obtained for dust samples, and their functional characteristics were predicted using PICRUSt2 2.5.0 and FAPROTAX 1.8.0 software. The culturable part of the bacterial community was examined for the presence of antibiotic-resistant strains with respect to β-lactams, tetracyclines, amphenicols, and aminoglycosides. The presence of bacteria resistant to ceftazidime, cefepime, and tetracycline was detected in all dust samples. The presence of bacteria resistant to meropenem and amikacin was only observed in the dust collected from leaves in the residential and traffic zones. The overall abundance of cultured antibiotic-resistant bacteria from the total heterotrophs ranged from 0.03% to 1.88%, with the highest percentage observed in dust from the residential zone. Notably, strains resistant to all antibiotics tested were observed in the leaf dust bacterial community. [ABSTRACT FROM AUTHOR]

Phenol and its chlorinated derivatives are introduced into the environment with wastewater effluents from various industries, becoming toxic pollutants. Phenol-degrading bacteria are important objects of research; among them, representatives of the genus Rhodoccocus are often highlighted as promising. Strain 7Ba was isolated by enrichment culture. A new isolate was characterized using culturing, biochemistry, high-throughput sequencing, microscopy (including electron microscopy), and functional genome analysis. Rhodococcus erythropolis strain 7Ba is able to grow on phenol and chlorophenols without losing its properties during long-term storage. It was shown that strain 7Ba is able to form viable but nonculturable (VBNC) forms during long-term storage under nutrient limitation, preserving both cell viability and the ability to degrade phenols. The ultrastructural organization of the vegetative forms of cells and VBNC forms was characterized. The following distinctive features were found: modifications (thickening) of cell membranes, cell size reduction, nucleoid condensation. Functional analysis of the genome showed the presence of genes for the degradation of alkanes, and two branches of the β-ketoadipate pathway for the degradation of aromatic compounds. Also, the genome of strain 7Ba contains several copies of Rpf (resuscitation promoting factor) genes, a resuscitation factor of resting bacterial forms. The new isolate strain 7Ba is a promising biotechnological agent that can not only utilize toxic aromatic compounds but also remain viable during long-term storage. For this reason, its further application as an agent for bioremediation can be successful under changing conditions of climate and given the deficiency of nutrient compounds in nature. Minor biostimulation will allow the strain to recover its metabolic activity and effectively degrade pollution. [ABSTRACT FROM AUTHOR]