Bacterial porin homologues have recently been found in seawater as a dissolved organic matter. However, the bacteria of origin have not been identified. This manuscript describes the isolation of the marine bacteria having similar antigenic proteins to porin Omp35La of Vibrio anguillarum. Colony forming bacteria from seawater on Marine Broth 2216E plate were screened to determine whether they have Omp35La-like proteins by colony western blotting with anti-Omp35La antibody. Among the 37 final positive isolates, 11 isolates were classified into the Vibrio-group, whereas 26 isolates were assigned to be non-Vibrio-group based on the biochemical properties. When outer membrane protein was purified and western blotting was performed, 8 our of 11 Vibrio-group and 10 out of 26 non-Vibrio-group isolates had antibody reactive proteins. This suggests that not only Vibrio but also other class bacteria are possibly the origin of the dissolved protein. The family Vibrionaceae specific PCR worked in 7 isolates of the Vibrio-group. However, V. anguillarum itself was not identified by PCR-RFLP assay.
Ectomycorrhizal colonization and morphotype assemblage of Quercus myrsinaefolia seedlings were compared under ambient (399μl liter-1 of CO2) atmospheric, elevated air temperature (ca. +4.5°C) (ET), and elevated air temperature (ca. +4.5°C) plus elevated atmospheric CO2 (753μl liter-1) (ET-EC) conditions in Experiment 1. In Experiment 2, the ectomycorrhizal status was compared under ambient (395μl liter-1 of CO2) and elevated CO2 (488μl liter-1) (EC) conditions. The total ectomycorrhizal colonization and the dry weight of the plants significantly decreased under the ET and ET-EC conditions, indicating that the elevated temperature must be above the optimum for ectomycorrhizal colonization. Three ectomycorrhizal morphotypes, Cenococcum geophilum type, Type 12 and Type 40, showed relatively higher colonization under the ambient condition. Colonization of Type 12 significantly decreased, and that of Type 40 was completely prevented by the ET and ET-EC treatments, suggesting that colonization of these two morphotypes is sensitive to the elevated temperature. The ergosterol content in the fine roots significantly increased under the EC condition, suggesting that the ectomycorrhizal fungal mass was increased by CO2 enrichment.
The number of endophytic bacteria in the stem of sugarcane cultivars collected from different sites in the Philippines ranged from 104 to 109 cells ml-1 juice. Bacterial population was correlated with the sugar content (% Brix) of the juice and varied depending on the cultivar and sampling site. Twenty-eight isolates had a positive reaction in the acetylene reduction assay (ARA). Presumptive tests indicated that 15 isolates were putative strains of Acetobacter diazotrophicus, 5 isolates showed similar characteristics to those of Herbaspirillum seropedicae, and 8 isolates consisted of Herbaspirillum rubribalbicans-like strains. This study confirmed the existence of N2-fixing endophytic bacteria in sugarcane cultivars in the Philippines.
Twenty-three microorganisms taken from the Inland Sea in Western Japan formed colonies on plates containing 2M NaCl, of which 15 isolates showed growth rates of more than 0.5 (doublings/h) at 30°C in the presence of 2M NaCl. The isolates thus selected were classified into two groups by their growth patterns in response to NaCl concentrations added externally. Four isolates (group I) did not grow in the presence of 20mM and 3M NaCl, but they showed a peak growth of 1.67-2.14 doublings/h at 0.5M. Three isolates (group IIA) grew in the presence of 20mM (0.92-0.95 doublings/h) and 3M (0.29-0.33 doublings/h) NaCl, indicating that they are halotolerant microorganisms. Another 8 microorganisms (group IIB) also showed the halotolerant growth pattern. These findings indicate that halotolerant microorganisms are widely distributed in seawater.
The occurrence of oxytetracycline (OTC) resistance was examined among bacteria isolated from intestinal contents of yellowtail, Seriola quinqueradiata, and the seawater environment where these animals are cultured. A high prevalence of OTC resistant bacteria was observed in all samples obtained before and after administration of OTC. The Vibrio/Aeromonas group were the predominant bacteria detected in the intestine samples. However, other genera also contained OTC-resistant bacteria.