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71.
Mahalingam R Jambunathan N Gunjan SK Faustin E Weng H Ayoubi P 《Plant, cell & environment》2006,29(7):1357-1371
We are using acute ozone as an elicitor of endogenous reactive oxygen species (ROS) to understand oxidative signalling in Arabidopsis. Temporal patterns of ROS following a 6 h exposure to 300 nL L(-1) of ozone in ozone-sensitive Wassilewskija (Ws-0) ecotype showed a biphasic ROS burst with a smaller peak at 4 h and a larger peak at 16 h. This was accompanied by a nitric oxide (NO) burst that peaked at 9 h. An analysis of antioxidant levels showed that both ascorbate (AsA) and glutathione (GSH) were at their lowest levels, when ROS levels were high in ozone-stressed plants. Whole genome expression profiling analysis at 1, 4, 8, 12 and 24 h after initiation of ozone treatment identified 371 differentially expressed genes. Early induction of proteolysis and hormone-responsive genes indicated that an oxidative cell death pathway was triggered rapidly. Down-regulation of genes involved in carbon utilization, energy pathways and signalling suggested an inefficient defense response. Comparisons with other large-scale expression profiling studies indicated some overlap between genes induced by ethylene and ozone, and a significant overlap between genes repressed by ozone and methyl jasmonate treatment. Further, analysis of cis elements in the promoters of ozone-responsive genes also supports the view that phytohormones play a significant role in ozone-induced cell death. 相似文献
72.
Monitoring of micro-organisms released deliberately into the environment is essential to assess their movement during the bio-remediation process. During the last few years, DNA-based genetic methods have emerged as the preferred method for such monitoring; however, their use is restricted in cases where organisms used for bio-remediation are not well characterized or where the public domain databases do not provide sufficient information regarding their sequence. For monitoring of such micro-organisms, alternate approaches have to be undertaken. In this study, we have specifically monitored a p-nitrophenol (PNP)-degrading organism, Arthrobacter protophormiae RKJ100, using molecular methods during PNP degradation in soil microcosm. Cells were tagged with a transposon-based foreign DNA sequence prior to their introduction into PNP-contaminated microcosms. Later, this artificially introduced DNA sequence was PCR-amplified to distinguish the bio-augmented organism from the indigenous microflora during PNP bio-remediation. 相似文献
73.
Pandey G Chauhan A Samanta SK Jain RK 《Biochemical and biophysical research communications》2002,299(3):404-409
We have earlier reported chemotaxis of a Gram-negative, motile Ralstonia sp. SJ98 towards p-nitrophenol (PNP), 4-nitrocatechol (NC), o-nitrobenzoate (ONB), p-nitrobenzoate (PNB), and 3-methyl-4-nitrophenol (MNP) that also served as sole source of carbon and energy to the strain [S.K. Samanta, B. Bhushan, A. Chauhan, R.K. Jain, Biochem. Biophy. Res. Commun. 269 (2000) 117; B. Bhushan, S.K. Samanta, A. Chauhan, A.K. Chakraborti, R.K. Jain, Biochem. Biophy. Res. Commun. 275 (2000) 129]. In this paper, we report chemotaxis of a Ralstonia sp. SJ98 toward seven different nitroaromatic compounds (NACs) by drop assay, swarm plate assay, and capillary assay. These NACs do not serve as sole carbon and energy source to strain SJ98 but are partially transformed in the presence of an alternate carbon source such as succinate. This is the first report showing chemotaxis of a bacterial strain toward co-metabolizable NACs. 相似文献
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Kinetics of urease-catalysed urea hydrolysis follows Arrhenius equation in the temperature range 10-50°C and shows an energy of activation equal to 7.14 kcal/mol. The kinetics of thermal inactivation of the enzyme is biphasic, In that half of the initial activity is destroyed more rapidly than the remaining half. The data are consistent with the rate equation: At = Afast·e-k fast -t + Aslow ·e-K slow -t where At is the residual activity at time t, Afast and Aslow, kfast and kslow are the amplitudes and the first-order rate constants of the fast and the slow phases, respectively. A similar activity decay (namely blphaslc) is also observed on storing the enzyme at +4 and ?4OC. The data suggest the existence of half-and-half distribution of sites which is a manifestation of a pre-exlstent site heterogeneity in the oligomeric protein molecule. 相似文献
76.
A Bemisia tabaci midgut protein interacts with begomoviruses and plays a role in virus transmission
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Vipin Singh Rana Sonam Popli Gunjan Kumar Saurav Harpreet Singh Raina Rahul Chaubey V. V. Ramamurthy R. Rajagopal 《Cellular microbiology》2016,18(5):663-678
Begomoviruses are a major group of plant viruses, transmitted exclusively by Bemisia tabaci (Gennadius) in a persistent circulative non‐propagative manner. The information regarding molecular and cellular basis underlying Begomovirus – whitefly interaction is very scarce. Evidences have suggested that the insect gut possesses some crucial protein receptors that allow specific entry of virus into the insect haemolymph. We have performed yeast two hybrid gut cDNA expression library screening against coat protein of Tomato leaf curl New Delhi virus (ToLCV) and Cotton leaf curl Rajasthan virus (CLCuV) as bait. Midgut protein (MGP) was the common protein found interacting with both ToLCV and CLCuV. MGP was localized in whole mount B. tabaci as well as in dissected guts through confocal microscopy. Pull down and dot blot assays confirmed in vitro interaction between ToLCV/CLCuV coat protein and MGP. Immunolocalization analysis also showed colocalization of ToLCV/CLCuV particles and MGP within insect's gut. Finally, anti‐MGP antibody fed B. tabaci, exhibited 70% reduction in ToLCV transmission, suggesting a supportive role for MGP in virus transmission. 相似文献
77.
Vikas Beniwal Rajesh Gunjan Goel Anil Kumar Vinod Chhokar 《Annals of microbiology》2013,63(2):583-590
The tannase producing strain Aspergillus heteromorphus MTCC 8818 was used in the present study for the production of tannase under solid state fermentation using Rosewood (Dalbergia sissoo) sawdust—a timber industry waste—as substrate. Various physico-chemical parameters were optimized for extracellular yield of tannase. Maximum tannase (1.84 U/g dry substrate) and gallic acid (5.4 mg/g ds) was observed at 30 °C after 96 h of incubation. Czapek dox medium was found to be the best moistening agent, with pH and relative humidity of 5.5 and 70 %, respectively. The constituents of Czapek dox medium were varied to enhance enzyme production. The optimum concentration of modified Czapek dox constituents contained 0.2 % NaNO3, 0.05 % K2HPO4 and MgSO4, 0.15 % KCl. Among the additional salts supplemented to Czapek dox medium, ZnSO4 and CuSO4 were found to have a stimulating effect, with a relative tannase activity of 116 and 111 %, respectively. Glucose as an external carbon source was found to be a repressor of enzyme production. 相似文献
78.
Yan Huang Alberto Hidalgo-Bravo Enjie Zhang Victoria E. Cotton Aaron Mendez-Bermudez Gunjan Wig Zahara Medina-Calzada Rita Neumann Alec J. Jeffreys Bruce Winney James F. Wilson Duncan A. Clark Martin J. Dyer Nicola J. Royle 《Nucleic acids research》2014,42(1):315-327
Linear chromosomes are stabilized by telomeres, but the presence of short dysfunctional telomeres triggers cellular senescence in human somatic tissues, thus contributing to ageing. Approximately 1% of the population inherits a chromosomally integrated copy of human herpesvirus 6 (CI-HHV-6), but the consequences of integration for the virus and for the telomere with the insertion are unknown. Here we show that the telomere on the distal end of the integrated virus is frequently the shortest measured in somatic cells but not the germline. The telomere carrying the CI-HHV-6 is also prone to truncations that result in the formation of a short telomere at a novel location within the viral genome. We detected extra-chromosomal circular HHV-6 molecules, some surprisingly comprising the entire viral genome with a single fully reconstituted direct repeat region (DR) with both terminal cleavage and packaging elements (PAC1 and PAC2). Truncated CI-HHV-6 and extra-chromosomal circular molecules are likely reciprocal products that arise through excision of a telomere-loop (t-loop) formed within the CI-HHV-6 genome. In summary, we show that the CI-HHV-6 genome disrupts stability of the associated telomere and this facilitates the release of viral sequences as circular molecules, some of which have the potential to become fully functioning viruses. 相似文献
79.
Vasundhera Gupta Gunjan Sharma T. N. R. Srinivas P. Anil Kumar 《Antonie van Leeuwenhoek》2014,106(6):1097-1103
A Gram-negative, rod shaped, motile, aerobic bacterium, designated as strain AK49T was isolated from a water sample from a mangrove forest in Coringa village, Andhra Pradesh, India. Strain AK49T was observed to form yellow coloured, smooth, circular, convex colonies on marine agar, with entire margins. Cells of strain AK49T are 0.5–1.0 µm wide and 1.5–3.5 µm long. Growth was observed at 25–37 °C (optimum 30 °C), 2–6 % NaCl (optimum 2 %) and pH 6–8 (optimum 7). Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain AK49T is closely related to two species recently reclassified as members of the genus Aliiglaciecola: Aliiglaciecola lipolytica JCM 15139T (sequence similarity 95.43 %) and Aliiglaciecola litoralis JCM 15896T (sequence similarity 96.91 %). The major cellular fatty acids of strain AK49T were found to include C16:0, C18:1ω7c and summed feature 3 (C16:1ω7c/C15:0 iso-2-OH). The polar lipid content of cell membrane was found to include phosphatidylethanolamine, phosphatidylglycerol, an unidentified aminolipid, an unidentified lipid and an unidentified glycolipid. The genomic DNA G+C content of strain AK49T was determined to be 41.9 mol%. Based on the taxonomic methods, including chemotaxonomic, phenotypic and phylogenetic approaches, strain AK49T is described here as a novel species belonging to the genus Aliiglaciecola, for which the name Aliiglaciecola coringensis sp. nov. is proposed. The type strain of Aliiglaciecola coringensis sp. nov. is AK49T (=MTCC 12003T = JCM19197T). 相似文献
80.
Gunjan Pandey Susan J. Dorrian Robyn J. Russell John G. Oakeshott 《Biochemical and biophysical research communications》2009,380(3):710-159
We report the isolation of a Pseudomonas sp. which is able to transform imidacloprid and thiamethoxam under microaerophilic conditions in the presence of an alternate carbon source. This bacterium, Pseudomonas sp. 1G, was isolated from soil with a history of repeated exposure to imidacloprid. Both insecticides were transformed to nitrosoguanidine (NNO), desnitro (NH), and urea (O) metabolites and a transformation pathway is proposed. This is the first conclusive report of bacterial transformation of the ‘magic nitro’ group which is responsible for the insect selectivity of neonicotinoid insecticides. 相似文献