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《Bioscience, biotechnology, and biochemistry》2013,77(12):2650-2656
An acidophilic volvocine flagellate, Chlamydomonas acidophila (Volvocales) that was isolated from an acid lake, Katanuma, in Miyagi prefecture, Japan was studied for growth, ultrastructural characterization, and metal tolerance.Chlamydomonas acidophila is obligately photoautotrophic, and did not grow in the cultures containing acetate or citrate even in the light. The optimum pH for growth was 3.5-4.5. To characterize metal tolerance, the toxic effects of Cd, Co, Cu, and Zn on this alga were also studied. Effective metal concentrations, which limited the growth by 50%, EC50 were measured, after 72h of static exposure. EC50s were 14.4 μM Cd2+, 81.3 μM Co2+, 141μM Cu2+, and 1.16 mM Zn2+ for 72 h of exposure. Thus, this alga had stronger tolerance to these metals than other species in the genus Chlamydomonas. 相似文献
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《Bioscience, biotechnology, and biochemistry》2013,77(6):1230-1237
Penicillum sp. 40, which can grow in an extremely acidic medium at pH 2.0 was screened from an acidic soil. This fungus produces xylanases when grown in a medium containing xylan as a sole carbon source. A major xylanase was purified from the culture supernatant of Penicillium sp. 40 and designated XynA. The molecular mass of XynA was estimated to be 25,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. XynA has an optimum pH at 2.0 and is stable in pH 2.0-5.0. Western blot analysis using anit-XynA antibody showed that XynA was induced by xylan and repressed by glucose. Also, its production was increased by an acidic medium. The gene encoding XynA (xynA) was isolated from the genomic library of Penicillium sp. 40. The structural part of xynA was found to be 721 bp. The nucleotide sequence of cDNA amplified by RT-PCR showed that the open reading frame of xynA was interrupted by a single intron which was 58 bp in size and encoded 221 amino acids. Direct N-terminal amino acid sequencing showed that the precursor of XynA had a signal peptide composed of 31 amino acids. The molecular mass caliculated from the deduced amino acid sequence of XynA is 20,713. This is lower than that estimated by gel electrophoresis, suggesting that XynA is a glycoprotein. The predicted amino acid sequence of XynA has strong similarity to other family11 xylanases from fungi. 相似文献
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Shijin Tang Yinping Pan Deshuai Lou Shunlin Ji Liancai Zhu Jun Tan Na Qi Qiong Yang Zhi Zhang Biling Yang Wenyan Zhao Bochu Wang 《Protein science : a publication of the Protein Society》2019,28(5):910-919
7α‐Hydroxysteroid dehydrogenase (7α‐HSDH) is an NAD(P)H‐dependent oxidoreductase belonging to the short‐chain dehydrogenases/reductases. In vitro, 7α‐HSDH is involved in the efficient biotransformation of taurochenodeoxycholic acid (TCDCA) to tauroursodeoxycholic acid (TUDCA). In this study, a gene encoding novel 7α‐HSDH (named as St‐2‐1) from fecal samples of black bear was cloned and heterologously expressed in Escherichia coli. The protein has subunits of 28.3 kDa and a native size of 56.6 kDa, which suggested a homodimer. We studied the relevant properties of the enzyme, including the optimum pH, optimum temperature, thermal stability, activators, and inhibitors. Interestingly, the data showed that St‐2‐1 differs from the 7α‐HSDHs reported in the literature, as it functions under acidic conditions. The enzyme displayed its optimal activity at pH 5.5 (TCDCA). The acidophilic nature of 7α‐HSDH expands its application environment and the natural enzyme bank of HSDHs, providing a promising candidate enzyme for the biosynthesis of TUDCA or other related chemical entities. 相似文献
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Acidophilic microbial communities associated with a natural, biodegraded hydrocarbon seepage 总被引:1,自引:0,他引:1
Characterization of microbial communities present in a surface petroleum seep in which hydrocarbons have been biodegraded for thousands of years in order to improve the understanding on natural petroleum biodegradation. DNA was extracted from a natural, surface petroleum seep and subjected to culture independent analysis (rRNA gene-based denaturing gradient gel electrophoresis and phylogenetic analysis of clone libraries). Molecular analysis suggested dominance by acidophilic bacteria, especially Alphaproteobacteria (mainly bacteria related to Acidiphilium and Acidocella). Archaea were not detected, but fungi were present. pH of the samples was around 3.5. Acidophilic microbial communities are associated with an acidic petroleum seep. Microbial community structure analysis gives information on the environmental conditions under which petroleum biodegradation occurs. This knowledge could be applied to define conditions for specific cultivation or activity measurements. The activity of acidophilic micro-organisms deserves more attention with respect to their involvement in natural petroleum degradation. This knowledge will contribute to the design of oil bioremediation strategies for polluted acidic settings. 相似文献
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McFrederick QS Wcislo WT Taylor DR Ishak HD Dowd SE Mueller UG 《Molecular ecology》2012,21(7):1754-1768
As honey bee populations decline, interest in pathogenic and mutualistic relationships between bees and microorganisms has increased. Honey bees and bumble bees appear to have a simple intestinal bacterial fauna that includes acidophilic bacteria. Here, we explore the hypothesis that sweat bees can acquire acidophilic bacteria from the environment. To quantify bacterial communities associated with two species of North American and one species of Neotropical sweat bees, we conducted 16S rDNA amplicon 454 pyrosequencing of bacteria associated with the bees, their brood cells and their nests. Lactobacillus spp. were the most abundant bacteria in many, but not all, of the samples. To determine whether bee-associated lactobacilli can also be found in the environment, we reconstructed the phylogenetic relationships of the genus Lactobacillus. Previously described groups that associate with Bombus and Apis appeared relatively specific to these genera. Close relatives of several bacteria that have been isolated from flowers, however, were isolated from bees. Additionally, all three sweat bee species associated with lactobacilli related to flower-associated lactobacilli. These data suggest that there may be at least two different means by which bees acquire putative probiotics. Some lactobacilli appear specific to corbiculate apids, possibly because they are largely maternally inherited (vertically transmitted). Other lactobacilli, however, may be regularly acquired from environmental sources such as flowers. Sweat bee-associated lactobacilli were found to be abundant in the pollen and frass inside the nests of halictids, suggesting that they could play a role in suppressing the growth of moulds and other spoilage organisms. 相似文献
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Tadayoshi Kanao Moe Onishi Yasuyuki Kajitani Yuki Hashimoto Tatsuya Toge Hiroshi Kikukawa 《Bioscience, biotechnology, and biochemistry》2018,82(1):152-160
Tetrathionate hydrolase (4THase), a key enzyme of the S4-intermediate (S4I) pathway, was partially purified from marine acidophilic bacterium, Acidithiobacillus thiooxidans strain SH, and the gene encoding this enzyme (SH-tth) was identified. SH-Tth is a homodimer with a molecular mass of 97 ± 3 kDa, and contains a subunit 52 kDa in size. Enzyme activity was stimulated in the presence of 1 M NaCl, and showed the maximum at pH 3.0. Although 4THases from A. thiooxidans and the closely related Acidithiobacillus caldus strain have been reported to be periplasmic enzymes, SH-Tth seems to be localized on the outer membrane of the cell, and acts as a peripheral protein. Furthermore, both 4THase activity and SH-Tth proteins were detected in sulfur-grown cells of strain SH. These results suggested that SH-Tth is involved in elemental sulfur-oxidation, which is distinct from sulfur-oxidation in other sulfur-oxidizing strains such as A. thiooxidans and A. caldus. 相似文献
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Four axenic strains of snow algae were examined for optimum pH under laboratory conditions using M-1 growth medium. Growth was measured using cell counts, cell measurements and absorbance readings at 440 nm. Strains C204 and C479A of Chloromonas sp. from the Adirondack Mountains, New York, grew optimally at pH 4.0 to 5.0. Strains C381F and C381G, Chloromonas polyptera (Fritsch) Hoh., Mull. & Roem. from the White Mountains, Arizona, grew optimally at pH 4.5 to 5.0. Growth was significantly higher at pH 4.0 in the northeastern species (Chloromonas sp.), but no significant difference was observed in final growth at pH 4.5, 5.0 and 5.5 between species. It is postulated that the more acidic precipitation in the northeastern United States may be selecting for strains of snow algae with greater tolerance to acidity than in strains from the southwestern United States or that the different pH optima reported are simply species differences. New York strain C204 was also grown in heavily buffered AM medium where it had an optimum pH of 5.0, but cells became irregularly shaped and tended to clump at pH 6.0 to 7.0. Growth of C204 in AM medium was significantly lower than in M-1 medium for snow algae. These findings justify the use of M-1 medium for this type of experimentation. 相似文献
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Mavromatis K Sikorski J Pabst E Teshima H Lapidus A Lucas S Nolan M Glavina Del Rio T Cheng JF Bruce D Goodwin L Pitluck S Liolios K Ivanova N Mikhailova N Pati A Chen A Palaniappan K Land M Hauser L Chang YJ Jeffries CD Rohde M Spring S Göker M Wirth R Woyke T Bristow J Eisen JA Markowitz V Hugenholtz P Klenk HP Kyrpides NC 《Standards in genomic sciences》2010,3(2):117-125
Vulcanisaeta distributa Itoh et al. 2002 belongs to the family Thermoproteaceae in the phylum Crenarchaeota. The genus Vulcanisaeta is characterized by a global distribution in hot and acidic springs. This is the first genome sequence from a member of the genus Vulcanisaeta and seventh genome sequence in the family Thermoproteaceae. The 2,374,137 bp long genome with its 2,544 protein-coding and 49 RNA genes is a part of the Genomic Encyclopedia of Bacteriaand Archaea project. 相似文献