Microbial remediation, especially the application of probiotics, has recently gained popularity in improving water quality and maintaining aquatic animal health. The efficacy and mechanism of mixed Bacillus for improvement of water quality and its effects on aquatic microbial community structure remain unknown. To elucidate these issues, we applied two groups of mixed Bacillus (Bacillus megaterium and Bacillus subtilis (A0 + BS) and Bacillus megaterium and Bacillus coagulans (A0 + BC)) to the aquaculture system of Crucian carp. Our results showed that the improvement effect of mixed Bacillus A0 + BS on water quality was better than that of A0 + BC, and the NH₄⁺-N, NO₂⁻-N, NO₃⁻-N, and total phosphorus (TP) concentrations were reduced by 46.3%, 76.3%, 35.6%, and 80.3%, respectively. In addition, both groups of mixed Bacillus increased the diversity of the bacterial community and decreased the diversity of the fungal community. Microbial community analysis showed that mixed Bacillus A0 + BS increased the relative abundance of bacteria related with nitrogen and phosphorus removal, such as Proteobacteria, Actinobacteria, Comamonas, and Stenotrophomonas, but decreased the relative abundance of pathogenic bacteria (Acinetobacter and Pseudomonas) and fungi (Epicoccum and Fusarium). Redundancy analysis showed that NH₄⁺-N, NO₂⁻-N, and TP were the primary environmental factors affecting the microbial community in aquaculture water. PICRUST analysis indicated that all functional pathways in the A0 + BS group were richer than those in other groups. These results indicated that mixed Bacillus A0 + BS addition produced good results in reducing nitrogenous and phosphorus compounds and shaped a favorable microbial community structure to further improve water quality.

Mangrove ecosystems are tropical environments that are characterized by the interaction between the land and the sea. As such, this ecosystem is vulnerable to oil spills. Here, we show a culture-independent survey of fungal communities that are found in the sediments of the following two mangroves that are located on the coast of Sao Paulo State (Brazil): (1) an oil-spill-affected mangrove and (2) a nearby unaffected mangrove. Samples were collected from each mangrove forest at three distinct locations (transect from sea to land), and the samples were analyzed by quantitative PCR and internal transcribed spacer (ITS)-based PCR-DGGE analysis. The abundance of fungi was found to be higher in the oil-affected mangrove. Visual observation and correspondence analysis (CA) of the ITS-based PCR-DGGE profiles revealed differences in the fungal communities between the sampled areas. Remarkably, the oil-spilled area was quite distinct from the unaffected sampling areas. On the basis of the ITS sequences, fungi that are associated with the Basidiomycota and Ascomycota taxa were most common and belonged primarily to the genera Epicoccum, Nigrospora, and Cladosporium. Moreover, the Nigrospora fungal species were shown to be sensitive to oil, whereas a group that was described as “uncultured Basidiomycota” was found more frequently in oil-contaminated areas. Our results showed an increase in fungal abundance in the oil-polluted mangrove regions, and these data indicated potential fungal candidates for remediation of the oil-affected mangroves.

Fungal spores are an important cause of allergic respiratory diseases worldwide. However, little is known about the intradiurnal pattern of spore concentrations of different fungal spore types in the air of the urban area. In this study, we evaluated bihourly variation in spore concentration of eight predominant fungal spore types in the atmosphere of Bratislava city (Agrocybe, Alternaria, Cladosporium, Coprinus, Exosporium, Epicoccum, Ganoderma, Leptosphaeria) with the aim to understand the relationships between the spore concentrations against associated environmental variables. Spore samples were collected using a Hirst-type volumetric aerospore trap from January to December 2016. Alternaria, Cladosporium, Epicoccum and Exosporium peaked during the daytime period between 10:00 and 16:00, while for Agrocybe, Ganoderma, Coprinus and Leptosphaeria, the nighttime peaks (20:00 and 04:00) were observed. Effect of a complex of environmental variables on bihourly concentrations of selected airborne fungal spore taxa was evaluated through multiple regression analysis. Air temperature, wind speed, sunshine duration and precipitation were positively associated with daytime spore types, while the association with nighttime spores was negative. In contrast, relative air humidity influenced negatively Exosporium daytime spore type but positively the Leptosphaeria nighttime spore type. Moreover, a circadian cycle of light and darkness was considered as an important predictor of nighttime spore levels. Among the atmospheric pollutants, PM₁₀ was positively associated with all analysed daytime spores, while except for Leptosphaeria, O₃ was negatively associated with nighttime spore types. NO₂ and PM₁₀ had mixed effects on nighttime spore levels. In general, air temperature, PM₁₀ and wind speed were environmental parameters with great influence on airborne fungal spore concentration, being present in eight, seven and four regression models, respectively. Constructed regression models which the best explained variation in fungal spore concentrations were those for Ganoderma (R² = 0.38) and Alternaria (R² = 0.31).