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71.
Kensuke Furukawa Kenzo Tonomura Akira Kamibayashi 《Bioscience, biotechnology, and biochemistry》2013,77(7):1577-1583
Metabolism of 2,4,4′-trichlorobiphenyl by Acinetobacter sp. strain P6 has been studied. When the incubation was carried out without shaking at 15°C, two isomeric monohydroxy compounds, a dihydrodiol compound, a dihydroxy compound, a meta-cleaved yellow compound and a dichlorobenzoic acid were detected by combined gas liquid chromatograph-mass spectrometry. As an additional metabolite, dichlorodihydroxy biphenyl, a dechlorinationhydroxylation product, was also detected. When the incubation mixture was shaken at 30°C, a meta-cleaved yellow compound was readily produced and predominantly accumulated in the reaction mixture upon further incubation. The major pathway of 2,4,4′-trichlorobiphenyl by Acinetobacter sp. P6 was considered to proceed oxidatively via 2.′3′-dihydro-2′,3′-diol compound, concomitant dehydrogenated 2′,3′-dihydroxy compound and then the 1′,2′-meta-cleaved yellow compound, i.e., 3-chloro-2-hydroxy-6-oxo-6(2,4-dichlorophenyl)hexa-2,4-dienoic acid. 相似文献
72.
Konosuke Sano Kenzo Yokozeki Koji Mitsugi 《Bioscience, biotechnology, and biochemistry》2013,77(12):2463-2464
Rice has evolved metabolic and morphological adaptations to low-oxygen stress to grow in submerged paddy fields. To characterize the molecular components that mediate the response to hypoxia in rice, we identified low-oxygen stress early response genes by microarray analysis. Among the highly responsive genes, five genes, OsHREF1 to OsHREF5, shared strong homology. They encoded small proteins harboring two EF-hands, typical Ca2+-binding motifs. Homologous genes were found in many land plants, including SlHREF in tomato, which is also strongly induced by hypoxia. SlHREF induction was detected in both roots and shoots of tomato plants under hypoxia. With the exception of OsHREF5, OsHREF expression was unaffected by drought, salinity, cold, or osmotic stress. Fluorescent signals of green fluorescent protein-fused OsHREFs were detected in the cytosol and nucleus. Ruthenium red, an inhibitor of intracellular Ca2+ release, repressed induction of OsHREF1-4 under hypoxia. The HREFs may be related to the Ca2+ response to hypoxia. 相似文献
73.
Hideoki Tanaka Hidekatsu Maeda Hideo Suzuki Akira Kamibayashi Kenzo Tonomura 《Bioscience, biotechnology, and biochemistry》2013,77(6):1429-1438
A photosynthetic bacterium, which can grow photosynthetically on benzoate, was isolated from sewage mud. Various kinds of aromatic compounds including heterocyclic aromatic compounds were photometabolized by the washed cells grown photosynthetically on benzoate with no lag period. Among these, thiophene-2-carboxylate was metabolized most rapidly to its (+)-tetrahydro derivative. The same strain could also grow on succinate under photosynthetic conditions. However, thiophene-2-carboxylate was only photometabolized after a long lag period by the washed cells grown photosynthetically on succinate, and the metabolite was not its (+)-tetrahydro derivative but (+)-3-hydroxytetrahydrothiophene-2-carboxylate. In the presence of chloramphenicol, an inhibitor of protein synthesis, the photometabolism of thiophene-2-carboxylate by the washed cells grown photosynthetically on benzoate was not affected at all, but the photometabolism of the same substrate by the washed cells grown photosynthetically on succinate was completely inhibited. These results indicate that a reduction system of broad substrate specificity for aromatic rings is already present in the benzoate-grown cells but absent in the succinate-grown cells. It seems that such a reduction system for aromatic rings is induced by an aromatic substrate. 相似文献
74.
Pei-Ling Wang Sang Kyun Koh Kun-Sub Chung Takeshi Uozumi Teruhiko Beppu 《Bioscience, biotechnology, and biochemistry》2013,77(5):1469-1477
We cloned in E. coli the whole 17 nif genes (nifQ-J) of Klebsiella oxytoca NG13 using pBR322 as a vector, and constructed a recombinant plasmid, pNOW25 (nif+, Apr, 42.6 kb). A non nif DNA fragment was deleted from the plasmid with XhoI, and a smaller plasmid, pNOK31 (nif+, Apr, 31.1 kb), was reconstructed.We constructed the restriction map of the cloned nif genes. The map was the same as that of the K. pneumoniae M5a1 nif genes as to the EcoRI, HindIII, BamHI and XhoI sites, but differed considerably in the PstI, SalI and BglII sites.E. coli KO60 containing pNOW25 or pNOK31 can grow on a N-free medium. The acetylene reduction activities of KO60 (pNOW25) and KO60 (pNOK31) were 280 nmol and 390 nmol/48 hr per 7 ml of N-free liquid medium, whereas the activity of K. oxytoca NG13 was 3800 nmol. Thus, the expressed activity of the nif system of K. oxytoca is rather low in E. coli even if the nif genes are cloned on a multicopy plasmid. 相似文献
75.
Takashi Matsumoto Keiko Okunishi Koh Nishida Masao Noguchi 《Bioscience, biotechnology, and biochemistry》2013,77(2):485-490
In order to obtain a basic information of plant cell suspension culture as a step toward the development of large scale culture, culture conditions of crown gall cells (auxin non-requiring cells) were investigated. Addition of yeast extract to culture medium was significantly effective for the growth and cell dispersion.In experiments on the ability of the cultured cells to utilize sugars as the carbon source, it was observed that galactose, added to the culture medium, markedly inhibited the cell growth.Pasteurization of the medium containing fructose as carbon source made it brownish by Maillard reaction and the medium apparently restrained the cell growth. However, the fructose medium sterilized by filtration was excellent for the cell growth as well as sucrose or glucose medium. In a jar fermentor, even the glucose medium became brownish by heat sterilization and the brown colored medium restrained the cell growth. Under optimum conditions, the doubling time was 1.1 day in exponential phase and 2.0 g of cell (dry weight) per 100 ml culture was obtained as the maximum yield. 相似文献
76.
77.
Chihiro Handa Tadahiro Okubo Aogu Yoneyama Masashi Nakamura Mari Sakaguchi Narumi Takahashi Mayumi Okamoto Ayumi Tanaka-Oda Tanaka Kenzo Tomoaki Ichie Takao Itioka 《Journal of plant research》2013,126(1):73-79
Macaranga myrmecophytes (ant-plants) provide their partner symbiotic ants (plant-ants) with food bodies as their main food, and they are protected by the plant-ants from herbivores. The amount of resource allocated to food bodies determines the plant-ant colony size and consequently determines the intensity of ant defense (anti-herbivore defense by plant-ants). As constraints in resource allocation change as plants grow, the plant-ant colony size is hypothesized to change with the ontogenesis of Macaranga myrmecophyte. To determine the ontogenetic change in the relative size of the plant-ant colony, we measured the dry weights of the whole plant-ant colony and all of the aboveground parts of trees at various ontogenetic stages for a myrmecophytic species (Macaranga beccariana) in a Bornean lowland tropical rain forest. Ant biomass increased as plant biomass increased. However, the rate of increase gradually declined, and the ant biomass appeared to reach a ceiling once trees began to branch. The ant/plant biomass ratio consistently decreased as plant biomass increased, with the rate of decrease gradually accelerating. We infer that the ontogenetic reduction in ant/plant biomass ratio is caused by an ontogenetic change in resource allocation to food rewards for ants related to the physiological changes accompanying the beginning of branching. 相似文献
78.
Bharat Thyagarajan Renwei Wang Heather Nelson Helene Barcelo Woon-Puay Koh Jian-Min Yuan 《PloS one》2013,8(6)
Mitochondrial DNA (mtDNA) copy number in peripheral blood is associated with increased risk of several cancers. However, data from prospective studies on mtDNA copy number and breast cancer risk are lacking. We evaluated the association between mtDNA copy number in peripheral blood and breast cancer risk in a nested case-control study of 183 breast cancer cases with pre-diagnostic blood samples and 529 individually matched controls among participants of the Singapore Chinese Health Study. The mtDNA copy number was measured using real time PCR. Conditional logistic regression analyses showed that there was an overall positive association between mtDNA copy number and breast cancer risk (Ptrend = 0.01). The elevated risk for higher mtDNA copy numbers was primarily seen for women with <3 years between blood draw and cancer diagnosis; ORs (95% CIs) for 2nd, 3rd, 4th, and 5th quintile of mtDNA copy number were 1.52 (0.61, 3.82), 2.52 (1.03, 6.12), 3.12 (1.31, 7.43), and 3.06 (1.25, 7.47), respectively, compared with the 1st quintile (Ptrend = 0.004). There was no association between mtDNA copy number and breast cancer risk among women who donated a blood sample ≥3 years before breast cancer diagnosis (Ptrend = 0.41). This study supports a prospective association between increased mtDNA copy number and breast cancer risk that is dependent on the time interval between blood collection and breast cancer diagnosis. Future studies are warranted to confirm these findings and to elucidate the biological role of mtDNA copy number in breast cancer risk. 相似文献
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