Natto-like fermented soybean products are manufactured and consumed in many Asian countries. In this study, we isolated thirty-four Bacillus strains capable of producing γ-polyglutamic acid (PGA) from natto in mountainous areas of South Asia and Southeast Asia and from soils in Japan. To elucidate the phylogeny of these PGA-producing strains, phylogenetic trees based on sequences of 16S rDNA, housekeeping genes of rpoB (RNA polymerase β-subunit) and fus (elongation factor G) were constructed. A phylogenetic tree based on 16S rDNA sequences showed that twenty-one isolates were clustered in the same group of B. subtilis. The other thirteen isolates were located in the cluster of B. amyloliquefaciens. Phylogenetic trees based on the partial sequences of rpoB and fus genes were similar to the phylogeny based on 16S rDNA sequences. The results of the present study indicate that PGA-producing strains isolated from local natto in Asian countries and soil in Japan can be divided into two species, B. subtilis and B. amyloliquefaciens.
The composition and the number of fecal or intestinal lactobacilli were determined in weaned piglets before (pre-administration and day 0) and during (days 4, 7, and 14) the administration of Lactobacillus plantarum strain Lq80 (daily dose=1010 cells). Fecal or intestinal lactobacilli were isolated, and the isolates were grouped by RAPD-PCR and further identified by 16S rDNA partial sequences. During administration, the number of lactobacilli in feces and intestinal contents (log cfu/g) increased from day 0 to day 4 (7.96 vs. 10.07, p<0.05), to day 7 (7.96 vs. 10.18, p<0.05), and to day 14 (7.96 vs. 9.02, p=0.07) in the administered group, although L. plantarum was isolated from the feces of piglets in the administered group at 5.0×106 cfu/g. The level of culturable lactobacilli was significantly higher on day 7 in the administered group than in the control group (8.93 vs. 10.18, p=0.0002). Furthermore, the minor species in the lactobacillal population under the control condition become detectable with the administration of strain Lq80. The oral administration of L. plantarum strain Lq80 was effective to stimulate the development of the lactobacillal population in the intestine of post-weaning piglets.
New and better drugs are needed for tuberculosis (TB), particularly for the multi-drug resistant (MDR) disease. However, the highly infectious nature of MDR Mycobacterium tuberculosis restricts its use for large scale screening of probable drug candidates. We have evaluated the potential of a screen based on a ‘fast grower’ mycobacterium to shortlist compounds which could be active against MDR M. tuberculosis. Sensitivity profiles of M. smegmatis, M. phlei and M. fortuitum as well as MDR clinical isolates of M. tuberculosis were determined against anti-TB drugs isoniazid and rifampicin. Among the three fast growers, M. smegmatis was found to display a profile similar to MDR M. tuberculosis. Subsequently we evaluated the performance of M. smegmatis as a ‘surrogate’ screen for 120 compounds which were synthesized for anti-TB activity. Fifty of these molecules were active against M. tuberculosis H37Rv at a minimum inhibitory concentration (MIC) cutoff of ≤12.50 μg/ml. The M. smegmatis based screen showed 100% specificity and 78% sensitivity vis-à-vis MDR M. tuberculosis. These results highlight the utility of M. smegmatis as a primary screen to shortlist compounds for advanced screening against MDR M. tuberculosis.
Citrobacter sp. strain KCTC 18061P was found to be able to decolorize textile plant effluent containing different types of reactive dyes. Effects of physico-chemical parameters, such as aeration, nitrogen source, glucose and effluent concentrations on the color removal of real dye effluent by this strain were investigated. The observed changes in the visible spectra indicated color removal by the absorption of dye to cells during incubation with the strain. This strain showed higher decolorization ability under aerobic than static culture conditions. With 1% glucose, this strain removed 70% of effluent color within 5 days. Decolorization was not significantly dependent on the nitrogen sources tested. Chemical oxygen demand (COD) and biological oxygen demand (BOD) were decreased in proportion to incubation times, and their removal rates were about 35% and 50%, respectively, at 7 days of culture.
Two yeast strains (ST-235 and ST-237) isolated from insect frass collected in northeastern Thailand, were identified as Pichia acaciae and a hitherto undescribed species based on the sequence analysis of the D1/D2 domain of 26S rDNA, ITS regions, and DNA-DNA reassociation experiments. The latter strain, ST-237 (=BCC 11769=NBRC 103638=JCM 12576), was described as Pichia koratensis sp. nov. Pichia koratensis is closely related to Pichia acaciae in the D1/D2 domain sequence of 26S rDNA and phenotypical characteristics but differs by 5 nucleotides (0.9%) from the type strain of P. acaciae and is clearly distinguished by the assimilation and fermentation of sucrose.