Abstract
Actinomycetes were isolated by plating of serially diluted samples onto humic acid-vitamin agar prepared with or without NaCl and characterized by physiological and phylogenetical studies. A total of 16 strains were isolated from hypersaline soil in Mongolia. All strains showed alkaliphilic characteristics and were able to abundantly grow in media with pH 9.0. Six strains were halotolerant actinomycetes (0 to 12.0% NaCl) and 10 strains were moderately halophiles (3.0 to 12.0% NaCl). Most strains required moderately high salt (5.0 to 10.0%) for optimal growth but were able to grow at lower NaCl concentrations. Among the 16 strains, 5 were able to grow at 45°C. Among the group of moderate halophilic actinomycetes, 9 strains were phylogenetically detected under the genus Nocardiopsis in the family Nocardiopsaceae. Results of scanning electron microscopic study demonstrated that most of the moderately halophilic strains under the genusNocardiopsis, produce synnemata structure. Overall phylogenetic analysis based on 16S rRNA gene sequences analysis revealed that all the 16 strains fell into 4 different genera:Nocardiopsis (9 strains), Isoptericola, (2 strains), Nesterenkonia (2 strains),Streptomyces (3 strains). This preliminary study demonstrated that the genusNocardiopsis is abundant and a recoverable actinomycetes group in Mongolian saline soil. Based on the position in phylogenetic tree of 16 isolates, there were new clusters which supposed to be novel species under the genera Nocardiopsis (possible new species 1) and Isoptericola (possible new species 1) in the family Nocardiopsaceae andPromicromonosporaceae, respectively. Key words: Classification, moderate halophilic and halotolerant actinomycetes, hypersaline soil, phylogenetic analysis, scanning electron microscope
Highlights
The aerobic halophilic bacteria have been scarcely studied as compared to the extensive literature on the physiology, biochemistry and ecology of the aerobic red halophilic archaea
Colony forming units of actinomycetes isolated from Mongolian saline soils collected from three different places of Uvs and Dornod province are shown in Figure 3 and Table 1
This study demonstrated that strains under the genus Nocardiopsis are abundant in Mongolian hypersaline soil and recoverable (Table 3)
Summary
The aerobic halophilic bacteria have been scarcely studied as compared to the extensive literature on the physiology, biochemistry and ecology of the aerobic red halophilic archaea (family Halobacteriaceae). Many halophiles and halotolerant microorganisms can grow over a wide range of salt requirement or salt tolerance at times depending on environmental and nutritional factors These extremophiles have been found in a variety of microenvironments including salt lakes and brines, saline soils, cold saline environments, alkaline saline habitats, and salted fish, meat and other foods (Ventosa et al, 1998 a, b). Identification and classification of halophilic microorganisms is generally achieved through comparison of the 16S rDNA sequence (Anton et al, 2000) or based on chemotaxonomic criteria (Kamekura, 1998)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
