The physicochemistry, metabolic properties, and microbial community structure of a tropical estuary persistently inundated with anthropogenic pollutants were elucidated using diverse analytical tools and a shotgun metagenomics approach. The physicochemistry of the Awoye estuary surface water (AEW) and sediment (AES) revealed higher values in the sediment for most of the parameters analyzed, while aside from copper and zinc, the concentrations of the detected heavy metals (Cd, Cr, Pb, Fe, As, Ni, Hg, Mn, Se) in the water and sediment were higher than the acceptable thresholds. Hydrocarbon content analysis revealed increasingly high concentrations of high molecular weight polycyclic aromatic hydrocarbons (HMW PAHs) in the sediment. Structurally, the predominant taxa in the AEW metagenome are Proteobacteria (50.35%), Alphaproteobacteria (43.31%), Brevundimonas (49.96%), and Leptolyngbya boryana (14.93%), while in the sediment (AES) metagenome, Proteobacteria (53.03%), Gammaproteobacteria (28.66%), Azospirillum (6.51%), and Acidihalobacter prosperus (7.56%) were preponderant. Statistical analysis of the two microbiomes (AEW, AES) revealed significant statistical differences (P < 0.05) at all the hierarchical levels. Functional characterization of the two metagenomes revealed extensive adaptations of the sediment microbiome to various environmental stressors as evident in the high numbers of putative genes involved in the degradation of diverse classes of aromatic hydrocarbons, efflux, detoxification, and transport of heavy metals, and metabolism of organic/inorganic nutrients. Findings from this study revealed that the estuary sediment is the sink for most of the anthropogenic pollutants and harbors the more adapted microbiome that could serve as a potential bioresource for the bioremediation of the perturbed estuary.

• Klíčová slova
• Anthropogenic pollutants, Heavy metals, Hydrocarbons, Shotgun metagenomics, Tropical estuary,
• Publikační typ
• časopisecké články MeSH

There is an increasing demand for bioinoculants based on plant growth-promoting rhizobacteria (PGPR) for use in agricultural ecosystems. However, there are still concerns and limited data on their reproducibility in different soil types and their effects on endemic rhizosphere communities. Therefore, this study explored the effects of inoculating the PGPR, Pseudomonas fluorescens strain UM270, on maize growth (Zea mays L.) and its associated rhizosphere bacteriome by sequencing the 16S ribosomal genes under greenhouse conditions. The results showed that inoculation with PGPR P. fluorescens UM270 improved shoot and root dry weights, chlorophyll concentration, and total biomass in the three soil types evaluated (clay, sandy-loam, and loam) compared to those of the controls. Bacterial community analysis of the three soil types revealed that maize plants inoculated with the UM270 strain showed a significant increase in Proteobacteria and Acidobacteria populations, whereas Actinobacteria and Bacteroidetes decreased. Shannon, Pielou, and Faith alpha-biodiversity indices did not reveal significant differences between treatments. Beta diversity revealed a bacterial community differential structure in each soil type, with some variation among treatments. Finally, some bacterial groups were found to co-occur and co-exclude with respect to UM270 inoculation. Considered together, these results show that PGPR P. fluorescens UM270 increases maize plant growth and has an important effect on the resident rhizobacterial communities of each soil type, making it a potential agricultural biofertilizer.

• Klíčová slova
• Bioinoculant, Maize, Plant growth-promoting Rhizobacteria, Plant rhizobiome,
• MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   růst a vývoj   MeSH
• biodiverzita MeSH
• biomasa MeSH
• fylogeneze MeSH
• kořeny rostlin * mikrobiologie   růst a vývoj   MeSH
• kukuřice setá * mikrobiologie   růst a vývoj   MeSH
• Pseudomonas fluorescens * genetika   růst a vývoj   fyziologie   MeSH
• půda * chemie   MeSH
• půdní mikrobiologie * MeSH
• rhizosféra * MeSH
• RNA ribozomální 16S genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• půda * MeSH
• RNA ribozomální 16S MeSH

Deforestation has a large impact on soil fertility, especially on steep slopes, but by applying sustainable management practices, local communities in Oaxaca (Mexico) have tried to avoid the most negative effects on the forest ecosystems they manage. In this study, the characteristics and bacterial community structure were investigated from soil sampled in triplicate (n = 3) with different land use, i.e., arable, natural forest, sustainable managed, and reforested soil. The pH was significantly higher in the arable (6.2) than in the forest soils (≤ 5.3), while the organic matter was > 2 times higher in the natural forest (80.4 g/kg) and sustainable managed soil (86.3 g/kg) than in the arable (36.8 g/kg) and cleared and reforested soil (39.3 g/kg). The higher organic matter content in the first two soils was due to leaf litter, absent in the other soils. The species richness (q = 0), the typical (q = 1) and dominant bacteria (q = 2) were not affected significantly by land use. The beta diversity, however, showed a significant effect of land use on species richness (p = 0.0029). Proteobacteria (40.135%) and Actinobacteria (20.15%) were the dominant bacterial phyla, and Halomonas (14.50%) and the Verrucomicrobia DA101 (3.39%) were the dominant genera. The bacterial communities were highly significantly different in soil with different land use considering the taxonomic level of genus and OTUs (p ≤ 0.003). It was found that the sustainable managed forest provided the local community with sellable wood while maintaining the soil organic matter content, i.e., sequestered C and without altering the bacterial community structure.

• Klíčová slova
• Arable soil, Cleared and reforested soil, Natural and sustainable managed forest soil, Soil characteristics,
• MeSH
• Actinobacteria * genetika   MeSH
• Bacteria genetika   MeSH
• ekosystém * MeSH
• lesy MeSH
• půda chemie   MeSH
• půdní mikrobiologie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• půda MeSH

Streptomycetes, typical soil dwellers, can be detected as common colonizers of human bodies, especially the skin, the respiratory tract, the guts and the genital tract using molecular techniques. However, their clinical manifestations and isolations are rare. Recently they were discussed as possible "coaches" of the human immune system in connection with certain immune disorders and cancer. This work aimed for the characterization and evaluation of genetic adaptations of a human-associated strain Streptomyces sp. TR1341. The strain was isolated from sputum of a senior male patient with a history of lung and kidney TB, recurrent respiratory infections and COPD. It manifested remarkably broad biological activities (antibacterial, antifungal, beta-hemolytic, etc.). We found that, by producing specific secondary metabolites, it is able to modulate host immune responses and the niche itself, which increase its chances for long-term survival in the human tissue. The work shows possible adaptations or predispositions of formerly soil microorganism to survive in human tissue successfully. The strain produces two structural groups of cytotoxic compounds: 28-carbon cytolytic polyenes of the filipin type and actinomycin X2. Additionally, we summarize and present data about streptomycete-related human infections known so far.

• Klíčová slova
• Streptomyces, actinomycin, cytolytic polyenes, hemolysis, human pneumonia, pathogenicity, secondary metabolites,
• Publikační typ
• časopisecké články MeSH

Streptomyces coelicolor genome carries two apparently paralogous genes, SCO4164 and SCO5854, that encode putative thiosulfate sulfurtransferases (rhodaneses). These genes (and their presumed translation products) are highly conserved and widely distributed across actinobacterial genomes. The SCO4164 knockout strain was unable to grow on minimal media with either sulfate or sulfite as the sole sulfur source. The SCO5854 mutant had no growth defects in the presence of various sulfur sources; however, it produced significantly less amounts of actinorhodin. Furthermore, we discuss possible links between basic interconversions of inorganic sulfur species and secondary metabolism in S. coelicolor.

• MeSH
• anthrachinony metabolismus   MeSH
• antibakteriální látky metabolismus   MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• kultivační média metabolismus   MeSH
• sekundární metabolismus MeSH
• sírany metabolismus   MeSH
• Streptomyces coelicolor enzymologie   genetika   růst a vývoj   metabolismus   MeSH
• thiosulfátsulfurtransferasa genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• actinorhodin MeSH Prohlížeč
• anthrachinony MeSH
• antibakteriální látky MeSH
• bakteriální proteiny MeSH
• kultivační média MeSH
• sírany MeSH
• thiosulfátsulfurtransferasa MeSH