Two bacterial consortia, K-3 and No. 22, capable of degrading aromatic hydrocarbons in crude petroleum at high rates were screened from crude petroleum-contaminated soil. The K-3 consortium required saturated hydrocarbons (4 g/l) fractionated from crude petroleum for the efficient degradation (20%) of aromatics (4 g/l) within seven days, whereas the No. 22 consortium degraded 66% of aromatics (4 g/l) without supplementation with saturates in fourteen days. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and a colony isolation procedure gave five and fourteen DNA bands, and six and three different shaped colonies, respectively from the K-3 and No. 22 communities. Among the strains isolated from the K-3 consortium, Pseudomonas aeruginosa was the predominant species and decomposed aromatic hydrocarbons in the presence of saturates, while among the pure cultures from the No. 22 community, Burkholderia multivorans strain Y4 and Pandoraea sp. strain Y1 degraded aromatics at high rates without saturates. However, in a mixed culture of the strains, the degradation of aromatic hydrocarbons by a consortium of three strains, Hyphomicrobium facile strain Y3, strains Y1 and Y4, was nearly as efficient as that by the No. 22 community.
A No.22 consortium was isolated from contaminated soils at oilfields by repeated transfer on a mineral salts medium with the aromatic hydrocarbon fraction from crude petroleum. The consortium was able to degrade aromatic hydrocarbons at high rates. Fourteen major DNA bands were detected in the consortium by PCR-DGGE. Three strains were capable of forming colonies on agarose plates containing mineral salts and aromatic hydrocarbons, and identified as Pandoraea sp. Y1, Hyphomicrobium facile Y3, and Burkholderia multivorans Y4 by 16S rRNA gene sequencing. The consortia of three cultures; an aromatic subculture, a saturated culture transferred from the subculture, and an aromatic obtained culture from the transferred culture, were compared using PCR-DGGE, a clone library, and quantitative real-time PCR. Burkholderia species containing strain Y4 became the dominant species in the saturated culture whereas its abundance decreased in the aromatic culture. Pandoraea sp. Y1, which was of low abundance in the saturated culture, and an unisolated bacterium, Brachymonas sp. F, in contrast, increased in the aromatic culture. The aromatic hydrocarbons were degraded by Pandoraea sp. Y1 and B. multivorans Y4, whereas the saturates were only degraded by B. multivorans Y4. The results indicate that the No.22 consortium adapts well to different carbon sources through a change in its predominant species. This study provides some basic information regarding bioremediation using the consortium.
Integrin α11 (ITGA11) is one of the collagen-binding integrin α chains; however, its biological significance remains unknown. To determine the functions of ITGA11, we performed a yeast two-hybrid screen using the cytoplasmic domain of ITGA11 as bait and transformed an EGY48 yeast strain with the baitcontaining plasmid using the plasmid from a human lung fibroblast cDNA library. This screen identified calcium-and integrin-binding protein 1 (CIB1) as prey. Recombinant ITGA11 and CIB1 were expressed in mammalian cells and used in coimmunoprecipitation experiments, which showed that full-length ITGA11 and CIB1 are also associated in vivo. Overexpression of CIB1 in the human lung myofibroblast MRC-5 cells decreased the expression of α-smooth muscle actin and fibronectin. Using a mouse model of pulmonary fibrosis (bleomycin-treatment), we detected elevated expression of CIB1 in lung tissues compared with controls. These data suggest that CIB1 may regulate pulmonary fibrosis in concert with IT-GA11.
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