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Munusamy Govindarajan Soon-Wo Kwon Hang-Yeon Weon 《World journal of microbiology & biotechnology》2007,23(7):997-1006
A group of endophytic diazotrophs were isolated from surface-sterilized roots and stems of different sugarcane varieties in
the Tamilnadu region of India. From these, four isolates were selected, based on the highest acetylene reduction activity.
Gene-specific PCR amplification confirmed the presence of nif-D genes in those isolates. The 16S rRNA sequence of isolates GR4 and GR7 had a 99.5% sequence similarity to the Pseudomonas sp. pDL01 (AF125317) and 16S rDNA sequence of isolate GR3 had a 100% similarity to that of Burkholderia vietnamiensis (AY973820). The 16S rDNA sequence of isolate GR9 was 99.79% similar to that of the Klebsiella pneumoniae type strain (KPY17657). Colonization by the isolates was confirmed using micropropagated sugarcane and sterile rice seedlings.
Isolate GR9, identified as Klebsiella pneumoniae, was consistently more active in reducing acetylene as compared with the other isolates. The effects of GR9 and the sugarcane
diazotroph Gluconacetobacter diazotrophicus were compared in inoculated micropropagated sugarcane plantlets. The effects of K. pneumoniae GR9, and four other diazotrophs, G. diazotrophicus, Herbaspirillum seropedicae, Azospirillum lipoferum 4B, and Burkholderia vietnamiensis in inoculated rice seedlings were compared. GR9 alone or in combination with the other diazotrophs performed best under pot
conditions. The combined effects of nitrogen fixation and endophytic colonization of this diazotroph may be useful for the
development of bio-inoculants. 相似文献
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Pyrolysis mass spectrometry (PyMS) is a rapid, simple, high-resolution analytical method based on thermal degradation of complex
material in a vacuum, and has been widely applied to the discrimination of closely related microbial strains. Minimally prepared
samples of embryogenic and non-embryogenic calluses derived from various higher plants (sweet potato, morning glory, Korean
ginseng, Siberian ginseng, and balloon flower) were subjected to PyMS for spectral fingerprinting. A dendrogram based on the
unweighted pair group method, with arithmetic mean of pyrolysis mass spectra, divided the calluses into Siberian ginseng embryogenic
callus and the others, which were subsequently divided into embryogenic and non-embryogenic callus groups, regardless of plant
species from which the calluses were derived. In the non-embryogenic callus group, the dendrogram was in agreement with the
known taxonomy of the plants. These results indicate that PyMS analysis could be applied for discriminating plant calluses
based on embryogenic capacity and taxonomic classification. 相似文献
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Root explants excised from carnation plants maintained in vitro formed off-white, friable calluses after three weeks of culture
on Murashige and Skoog (MS) medium supplemented with 1 mg l−1 thidiazuron (TDZ) and 1 mg l−1 α-naphthalaneacetic acid (NAA). These calluses were subsequently transferred to MS basal medium where, after an additional
four weeks of culture, approximately 50% of the calluses formed somatic embryos. However, calluses formed on root explants
that had been cultured on MS medium supplemented with 2,4-dichlorophenoxyacetic acid did not produce somatic embryos upon
transfer to MS basal medium. Somatic embryos developed into plantlets and subsequently were grown to maturity. These results
indicate that root explants have a high competence for somatic embryogenesis in carnation.
J. Seo and S.W. Kim contributed equally to this work. 相似文献
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Protective effect of serotonin on 6-hydroxydopamine- and dopamine-induced oxidative damage of brain mitochondria and synaptosomes and PC12 cells 总被引:3,自引:0,他引:3
Jong Weon Park Young Chul Youn Oh Sang Kwon Yoon Young Jang Eun Sook Han Chung Soo Lee 《Neurochemistry international》2002,40(3):769-233
The present study elucidated the effects of indoleamines (serotonin, melatonin, and tryptophan) on oxidative damage of brain mitochondria and synaptosomes induced either by 6-hydroxydopamine (6-OHDA) or by iron plus ascorbate and on viability loss in dopamine-treated PC12 cells. Serotonin (1-100 microM), melatonin (100 microM), and antioxidant enzymes attenuated the effects of 6-OHDA, iron plus ascorbate, or 1-methyl-4-phenylpyridinium on mitochondrial swelling and membrane potential formation. Serotonin and melatonin decreased the attenuation of synaptosomal Ca(2+) uptake induced by either 6-OHDA alone or iron plus ascorbate. Serotonin and melatonin inhibited the production of reactive oxygen species, formation of malondialdehyde and carbonyls, and thiol oxidation in mitochondria and synaptosomes and decreased degradation of 2-deoxy-D-ribose. Unlike serotonin, melatonin did not reduce the iron plus ascorbate-induced thiol oxidation. Tryptophan decreased thiol oxidation and 2-deoxy-D-ribose degradation but did not inhibit the production of reactive oxygen species and formation of oxidation products in the brain tissues. Serotonin and melatonin attenuated the dopamine-induced viability loss, including apoptosis, in PC12 cells. The results suggest that serotonin may attenuate the oxidative damage of mitochondria and synaptosomes and the dopamine-induced viability loss in PC12 cells by a decomposing action on reactive oxygen species and inhibition of thiol oxidation and shows the effect comparable to melatonin. Serotonin may show a prominent protective effect on the iron-mediated neuronal damage. 相似文献
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Jae-Hyung Ahn Byoung-chan Kim Byung-Yong Kim Soo-Jin Kim Jaekyeong Song Soon-Wo Kwon Hang-Yeon Weon 《Journal of microbiology (Seoul, Korea)》2014,52(6):460-464
Strain CO 4–7T was isolated from greenhouse soil used for cultivation of cucumbers in Korea. The 16S rRNA gene sequence of strain CO 4–7T showed the highest sequence similarity with Paenibacillus contaminans CKOBP-6T (94.2%) among the type strains. Strain CO 4–7T was a strictly aerobic, Gram-staining-positive, endospore-forming, and motile rodshaped bacterium. Strain CO 4–7T grew at 10–45°C (optimum, 30°C), at pH 6.0–7.5 (optimum, pH 6.5) and in the presence of 0–5% NaCl (optimum, 0.5%). The DNA G+C content of strain CO 4–7T was 48.5 mol%. It contained MK-7 as the major isoprenoid quinone and anteiso-C15:0 (51.8%), C16:0 (12.7%), and iso-C16:0 (8.6%) as the major fatty acids. The cell wall contained meso-diaminopimelic acid. Based on evidence from our polyphasic taxonomic study, it was concluded that strain CO 4-7T should be classified as a novel species of the genus Paenibacillus, for which, the name Paenibacillus cucumis sp. nov. is proposed. The type strain is CO 4–7T (=KACC 17444T=JCM 19515T). 相似文献
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Doo Hyun Chung Kyeong Cheon Jung Weon Seo Park Im-Soon Lee Weon Jin Choi Chong-Jae Kim Seong Hoe Park Youngmee Bae 《Molecules and cells》2001,10(6):642-646
To induce proper immune responses, T lymphocytes require two types of stimuli, antigen-specific and costimulatory signals. Among costimulatory molecules, CD28-engagement promotes the survival and proliferation of both naive and memory T cells. In addition, it is now believed that Fas may play a role in T cell activation in the human system. It is, however, controversial whether Fas can act as a costimulatory signal in the murine system. Thus, we investigated fundamental differences in the capacity to induce proliferation of T cells between Fas and CD28 in mice. Fas-mediated T cell proliferation was observed only with a full mitogenic dose of anti-CD3 antibodies, whereas CD28 engagement was able to enhance T cell proliferation in the presence of a suboptimal level of anti-CD3 antibody. Furthermore, Fas-engaged T cells showed faster response in the upregulation of CD25 and CD69 expression than CD28-engaged ones. Here, we report that Fas might play a role in mature T cell activation in the mouse system through a different mechanism from that in CD28 costimulation. 相似文献
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Enhanced Mercury Biosorption by Bacterial Cells with Surface-Displayed MerR 总被引:5,自引:1,他引:4 下载免费PDF全文
Weon Bae Cindy H. Wu Jan Kostal Ashok Mulchandani Wilfred Chen 《Applied microbiology》2003,69(6):3176-3180
The metalloregulatory protein MerR, which exhibits high affinity and selectivity toward mercury, was exploited for the construction of microbial biosorbents specific for mercury removal. Whole-cell sorbents were constructed with MerR genetically engineered onto the surface of Escherichia coli cells by using an ice nucleation protein anchor. The presence of surface-exposed MerR on the engineered strains enabled sixfold-higher Hg2+ biosorption than that found in the wild-type JM109 cells. Hg2+ binding via MerR was very specific, with no observable decline even in the presence of 100-fold excess Cd2+ and Zn2+. The Hg2+ binding property of the whole-cell sorbents was also insensitive to different ionic strengths, pHs, and the presence of metal chelators. Since metalloregulatory proteins are currently available for a wide variety of toxic heavy metals, our results suggest that microbial biosorbents overexpressing metalloregulatory proteins may be used similarly for the cleanup of other important heavy metals. 相似文献