Variety of Culturable Microorganisms in Atmospheric Aerosol of Southwestern Siberia
Tech Area / Field
- ENV-APC/Air Pollution and Control/Environment
- BIO-CGM/Cytology, Genetics and Molecular Biology/Biotechnology
- ENV-EHS/Environmental Health and Safety/Environment
8 Project completed
Senior Project Manager
Melnikov V G
State Research Center of Virology and Biotechnology VECTOR, Russia, Novosibirsk reg., Koltsovo
- Universität Mainz / Institut fur Physik der Atmosphare, Germany, Mainz
Project summaryLiterature data and our own studies show that a large number of culturable microorganisms are found in the atmosphere at the altitudes starting from the ground surface to several kilometers. Numerical estimates show that microorganisms forming part of aerosol particles may be in the atmosphere for a long time (about a month). In the process of wandering, these microorganisms are subjected to the effect of different unfavorable factors, which may either cause their loss or change their characteristics. Long-term being in atmospheric aerosol might be one of the reasons of variability of microorganisms and the emergence of new strains including ones that are pathogenic for man. However, these questions remained uninvestigated until recently, first of all, because of the absence of detailed information on long-term variations in the number and representation of culturable microorganisms in the atmosphere.
The specialists of FSUE SRC VB “Vector” have been conducting the monitoring of the number and representation of culturable microorganisms in atmospheric aerosol at the altitudes up to 7000 m for more than 5 years. More than 500 samples were sampled and analyzed with traditional cultural methods during this period. Morphological peculiarities of the detected microorganisms were studied visually and by light microscopy using the phase contrast method. Taxonomic groups the detected microorganisms referred to were determined to the genus.
Microorganisms of widespread genera of different kingdoms were detected in tested samples. Microorganisms isolated from air aerosols included a large number of strains, which corresponded to the description of none of the known taxons by their phenotypical characteristics. In some cases, the potential pathogenicity of detected microorganism was determined. More than 40% of coccoid microorganisms and 32% of actinomyces manifest plasmocoagulation activity in vitro. 88% of the studied actinomyces have the ability to hemolysis. This result indicates high potential pathogenicity of microorganisms in the atmosphere and their possible effect on the morbidity of the region’s population.
Carrying out profound two-year-long monitoring of the microbiological composition of the atmosphere will allow creating a bank of microorganisms. The addition and more detailed characterization of new microorganisms will probably enable us to reveal the relationship between the variety of culturable microorganisms and the altitude of sampling, the season and meteorological characteristics. The study of the obtained collection of “atypical” microorganisms, will probably allow us to extend our knowledge of the taxomonic composition of atmospheric microflora, to evaluate the variability of microorganisms under the influence of environmental factors and, possibly, to trace the emergence of new strains. Detailed characterization of samples will be the basis of the attempt to interrelate the observed variety of culturable microorganisms in samples and their possible sources and to evaluate the changes occurring in microorganisms during their emergence in the atmosphere.
Main goal of the project: the analysis of microorganism samples collected from atmospheric air of Southwestern Siberia at different altitudes in different seasons.
Anticipated results of the project:
- experimental data for two years of observations on the distribution of microorganism concentrations and species by altitudes and seasons will be obtained;
- the taxonomic groups the detected bacteria and fungi refer to as well as the strains that morphologically do not differ from typical representatives of known taxons will be determined, their occurrence in atmospheric air samples will be determined;
- the characteristics of fat-acidic compositions of the walls of “typical” bacteria will be studied, and it will be compared with that of typical representatives of known microorganism taxons;
- in addition, some kinds of enzymatic activity, pathogenicity of bacteria in vitro and phytopathogenicity of fungi, some characteristics of toxin-formation and adaptability of isolated fungi to extreme environmental factors will be evaluated;
- the regularities of distribution of microorganism concentrations and species by the altitudes and seasons will be evaluated, and the obtained data will be summarized in a form of simple empirical dependences.
New experimental results have great fundamental value for understanding:
- the composition and variability of the “microbiological background” of the atmosphere of Southwestern Siberian region;
- the degrees of the effects of environmental factors on pheno- and genotypical characteristics of microorganisms;
- their conventional pathogenicity for man;
- the participation of different sources in the formation of the “microbiological background” of the atmosphere of Southwestern Siberia.
As atmospheric microorganisms can be transferred over large distances (including other continents), these data are interesting for the whole world community.
The above results may find practical application in the following areas: microbiology – the detection of new microorganism strains as well as their phenotypically differing variants; ecology – data on the “microbiological background” of the atmospheric air of the region and its potential danger for the population; meteorology – the determination of possible microbiological markers allowing us to record long-term transfers of air masses from different regions of the Earth to Southwestern Siberia as well as the contribution of remote aerosol sources of these regions to the formation of aerosol pollutants of atmosphere of Southwestern Siberia.
Methodology of research. Atmospheric air sampling for the detection of culturable microorganisms in it will be performed using impingers with the volume rate of 50 l/min, in which solution for maintaining the microorganisms viability is poured at the volume of 50 ml. Samples will be collected 1 time during the last 10 days of each month at the altitudes of 7000 – 500 m during aircraft probing of atmosphere; 8 on-ground samples will be collected 1 time in the middle of each month during a day to determine the daily dependence of the number and representation of microorganisms at the site of FSUE SRC VB “Vector”, and 1 on-ground sample will be collected daily for a week 1 time during a season (quarter) to reveal these dynamics for a longer period. It should be noted that no money is requested to pay for the rent of an airplane, as now the payment is made from other sources. However, as one can’t guarantee that financing of the rent of the airplane will continue for the whole period of the project fulfillment. If it is not possible to carry out aircraft probing, the same number of on-ground samples will be additionally collected instead of altitude samples.
The methodology of microorganism identification will be based on standard methods; it will be performed by cultural, optical and physico-chemical methods according to the classifiers of bacteria and fungi. The main attention will be paid to revealing possible differences of the detected microorganisms from typical representatives of known taxons. Pure microorganism lines will be isolated for revealing these differences; they will be studied with additional tests.
- The list of nutrient media used for the analysis of fungi will be extended (in particular, wort-agar, peptone-corn agar, potato-dextrose agar and other liquid and agarized media will be added).
- Screening of the isolated strains for antibiotic activity will be performed on test organisms at the cultivation on solid and liquid media using agar blocks and paper disks.
- Toxin formation by isolated fungi will be investigated on some sensitive microorganisms and protozoa.
- After 7-10 days of growth, culture fluid of the studied fungi will be tested for phytotoxicity with respect to seeds (wheat, peas) and sprouts of plants (corn).
- The reaction of the isolated fungal strains to ultraviolet rays will be studied with the method of irradiating fugal spores by a UV source and revealing the survival criteria by the number of microcolonies grown from irradiated spores as compared to non-irradiated ones.
- The methods of analyzing thermosensitivity of microorganisms – cultivation at high and low temperatures – will be used.
- The methods of evaluation of enzymatic activity of bacteria (determination of caseinolytic activity, gelatin proteolysis, lecitinase and lipase activities, etc.) will be used.
- In some cases, for indirect evaluation of pathogenicity of the detected microorganism cultures in experiments in vitro, the determination of their plasmocoagulation, hemolytic and fibrinolytic activities will be performed.
- Fat acid composition of the cell walls of “atypical” bacteria will be determined with the methods of liquid chromatography.
- In some cases, methods of genomic analysis including the determination of nucleotide composition of chromosome DNA of the strains and the method of genomic fingerprinting will be used.
Role of Foreign Collaborators.
The participation of Foreign Collaborators is proposed in: discussions of obtained results, information exchange, making of commentaries for technical reports (quarter, annual, final, etc.), conducting of joint symposiums and working seminars.