Diversity Of Culturable Microorganisms Research Articles

Gastrointestinal tract microbial community of Babylonia areolata and its diversity are closely correlated with the outbreak of disease

The intestinal microbiome is important for the health of aquatic animals. However, in Babylonia, the combination of gastrointestinal tract (GI) bacterial symbionts has barely been explored. In this study, from a farm with naturally occurring diseases, we collected Babylonia areolata in three different states, that is “diseased” (group D), “health” (group H) and “subhealth” (group SH) and aimed to reveal the relationship between disease occurrence and GI microbiota of B. areolata. Diversity analysis illustrated that GI microbial diversity of group D was obviously lower than that of group H on phylum level and genus level, and GI microbial diversity of group SH was between group D and H. KEGG analysis showed that the physiological activities of pathogenic microorganisms in group D increased significantly, compared with group H. Metagenomics analysis demonstrated the expressions of virulence genes in group D enhanced obviously, compared with group H. In addition, the diversity of culturable microorganisms from the GI contents of group D was dramatically lower than that of group H. A total of 22 species were obtained from the GI contents of group H. However, only four species were obtained from group D, and two important pathogens, Vibrio harveyi and Vibrio tubiashii, were dominant microbiota. These results indicate that the decline of GI microbial diversity in B. areolata is highly associated with the occurrence of disease. We speculated environmental factors led to the decline of GI microbial diversity, which could promote propagation of pathogenic microbes (such as V. harveyi and V. tubiashii). Our findings provide new insights into the disease outbreak of B. areolata and provide propose that the preservation of GI microbial diversity at the early phases can effectively prevent the occurrence of disease.

A survey of microbial contamination in aviation fuel from aircraft fuel tanks.

Microbial contamination poses a great threat to aviation system security through mechanisms such as microbiologically influenced corrosion (MIC), fuel filter clogging, and fuel deterioration. In this study, a survey of microbial contamination in aviation fuel obtained from aircraft fuel tanks was performed to test the relationship between microbial contamination and aircraft service life. The contaminating microorganisms were counted, isolated, identified, and subjected to preliminary characterization. A low risk of microbial contamination in the selected samples was confirmed, and there was no significant difference in the counts between culturable bacteria and fungi (p > 0.05). Phylogenetic analysis tree indicated that the diversity of culturable microorganisms was rather low, with 17 bacterial isolates belonging to 13 genera and 12 fungal isolates belonging to 5 genera. No yeast was isolated. The growth characteristics of these isolates indicated that the aircraft fuel tanks harbored various microorganisms that were able to utilize the aviation fuel as a source of carbon and energy. Meanwhile, some isolates caused emulsification and produced acid. The conclusions of this study were that various hazardous microorganisms can root in aircraft aviation fuel tanks. There was no relationship between microbial contamination and aircraft service life (p > 0.05), and continuous good maintenance suppressed microbial proliferation.

CULTURABLE MICROORGANISMS IN HIGH-ALTITUDE ATMOSPHERIC AEROSOL SAMPLES COLLECTED ABOVE NORTHERN SIBERIA BY AIRCRAFT SOUNDING

To contribute to the comprehensive study of atmospheric pollution in Siberia, aircraft soundingwas carried out in Northwestern Siberian along the following route: Novosibirsk - Surgut - Igarka - Novosibirsk. This work was aimed at studying the quantity and representation of culturable microorganisms and other biogenic components of the atmosphere at altitudes up to 8,000 m. The air samples were collected to impingers (flow rate 50 ± 5 L/min) where 50 ml of Hanks’ solution (ICN Biomedicals) was used as the sorbing liquid and applied on the fibrous filters. The concentration of biogenic material was recorded, and the concentration and diversity of culturable microorganisms were determined in total protein samples. It was found that the samples of atmospheric air contained 158 mesophilic and psychrophilic microorganisms represented by such genera as Micrococcus, Staphylococcus, Bacillus, Nocardia, Arthrobacter, and Rhodococcus. Also, Actinomycete, yeast and fungal cultures were also isolated. Non-sporiferous bacteria were widely presented at all altitudes. Enzymatic activity of the isolated microorganisms and a number of pathogenicity factors present were investigated. The data on quantity and representation of culturable microorganisms and other biogenic components at altitudes up to 8000 m in Northwestern Siberia were obtained for the first time. It is a significant contribution to the study of the atmosphere of this region. The patterns of the observed biodiversity of microorganisms, associated with the sampling altitude or geographic location, should be determined infurther research.

Diversity of culturable microorganisms and occurrence of Listeria monocytogenes and Salmonella spp. in Tuber aestivum and Tuber melanosporum ascocarps

The aim of this study was to investigate the total mesophilic microorganisms, Pseudomonas genus, Enterobacteriaceae family, mold and yeast counts and the presence of Listeria monocytogenes and Salmonella spp on Tuber aestivum and Tuber melanosporum ascocarps. The results confirmed that the major percentage of the microorganisms, approximately 9.0 log ufc/g, were present in the peridium, the glebas of healthy truffles being practically free of microorganisms. The predominant microbial group was the Pseudomonas averaging 8.3 and 8.4 log cfu/g on T. aestivum and T. melanosporum whole ascocarps, respectively. The Enterobacteriaceae also achieved high populations, especially in T. aestivum truffles, with 6.3 log cfu/g. Molds and yeasts never exceeded 5.0 log cfu/g. The characterization of the isolates revealed that the fluorescens pseudomonads were the most prevalent. Raoultella terrigena and Enterobacter intermedius were the dominant Enterobacteriaceae. The identification of the yeast isolates revealed five species: Debaryomyces hansenii, Issatchenkia scutulata, Rhodotorula aurantiaca, Saccharomyces dairensis and Trichosporon beigelii subspecies A and B. The mold genera detected in both species of truffles were Aspergillus, Cladosporium, Penicillium and Fusarium, Trichoderma being present only in T. aestivum. L. monocytogenes was found in 10% of the samples of T. aestivum analysed but Salmonella spp. was not detected. Knowledge of the microbial population in terms of possible food borne and pathogen microorganisms is very useful for establishing successful disinfection and storage methods to prolong the shelf-life of ascocarps of T. aestivum and T. melanosporum.