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91.
Sumanta Dey Mithu Guha Athar Alam Manish Goyal Samik Bindu Chinmay Pal Pallab Maity Kalyan Mitra Uday Bandyopadhyay 《Free radical biology & medicine》2009,46(2):271-281
Activation of the mitochondrial apoptosis pathway by oxidative stress has been implicated in hepatocyte apoptosis during malaria. Because mitochondria are the source and target of reactive oxygen species (ROS), we have investigated whether hepatocyte apoptosis is linked to mitochondrial pathology and mitochondrial ROS generation during malaria. Malarial infection induces mitochondrial pathology by inhibiting mitochondrial respiration, dehydrogenases, and transmembrane potential and damaging the ultrastructure as evident from transmission electron microscopic studies. Mitochondrial GSH depletion and formation of protein carbonyl indicate that mitochondrial pathology is associated with mitochondrial oxidative stress. Fluorescence imaging of hepatocytes documents intramitochondrial superoxide anion (O2?) generation during malaria. O2? inactivates mitochondrial aconitase to release iron from iron–sulfur clusters, which forms the hydroxyl radical (OH) interacting with H2O2 produced concurrently. Malarial infection inactivates mitochondrial aconitase, and carbonylation of aconitase is evident from Western immunoblotting. The release of iron has been documented by fluorescence imaging of hepatocytes using Phen Green SK, and mitochondrial OH generation has been confirmed. During malaria, the depletion of cardiolipin and formation of the mitochondrial permeability transition pore favor cytochrome c release to activate caspase-9. Interestingly, mitochondrial OH generation correlates with the activation of both caspase-9 and caspase-3 with the progress of malarial infection, indicating the critical role of OH. 相似文献
92.
A solid‐state fermentation (SSF) system for production of an industrially important enzyme laccase by Pleurotus ostreatus was developed by using potato dextrose yeast extract medium and polyurethane foam as a supporting material. The maximum laccase production in the SSF system was as high as 3×105 U/L. Addition of inducers, such as copper and ferulic acid, further enhanced the laccase production in SSF. Moreover, the time required for the maximum laccase production was reduced to 6 days compared to 10 days reported earlier. The improvement achieved by the SSF system was investigated by comparing it to a submerged fermentation system (SmF), both experimentally and by using a standard theoretical model along with a parameter sensitivity analysis. Laccase production in SSF was found to be twice of that in SmF. One of the main reasons for higher laccase production in SSF compared to SmF was possibly due to the presence of higher proteolytic activity in SmF. Strong proteolytic activity in SmF presumably caused subsequent laccase degradation, which lowered the ultimate laccase production in SmF compared to SSF. 相似文献
93.
Fourteen polymorphic microsatellite loci were developed for the raccoon tick (Ixodes texanus). Three multiplexed panels comprising the loci were developed and 50 ticks collected from two infected raccoons (Procyon lotor) were genotyped. The number of alleles per locus ranged from five to 22, and single locus heterozygosities ranged from 0.46 to 0.94. Future research will further our understanding of I. texanus biology and help in elucidating the effects of life-history variation on parasite population genetic structure, using I. texanus as a model organism. 相似文献
94.
Yasuharu Kushida Masak Takaine Kentaro Nakano Toshiro Sugai Krishna Kumar Vasudevan Mayukh Guha Yu‐Yang Jiang Jacek Gaertig Osamu Numata 《The Journal of eukaryotic microbiology》2017,64(3):293-307
Ciliates such as Tetrahymena thermophila have two distinct nuclei within one cell: the micronucleus that undergoes mitosis and meiosis and the macronucleus that undergoes amitosis, a type of nuclear division that does not involve a bipolar spindle, but still relies on intranuclear microtubules. Ciliates provide an opportunity for the discovery of factors that specifically contribute to chromosome segregation based on a bipolar spindle, by identification of factors that affect the micronuclear but not the macronuclear division. Kinesin‐14 is a conserved minus‐end directed microtubule motor that cross‐links microtubules and contributes to the bipolar spindle sizing and organization. Here, we use homologous DNA recombination to knock out genes that encode kinesin‐14 orthologues (KIN141, KIN142) in Tetrahymena. A loss of KIN141 led to severe defects in the chromosome segregation during both mitosis and meiosis but did not affect amitosis. A loss of KIN141 altered the shape of the meiotic spindle in a way consistent with the KIN141's contribution to the organization of the spindle poles. EGFP‐tagged KIN141 preferentially accumulated at the spindle poles during the meiotic prophase and metaphase I. Thus, in ciliates, kinesin‐14 is important for nuclear divisions that involve a bipolar spindle. 相似文献
95.
The photosynthetic response of trees to rising CO2 concentrations largely depends on source-sink relations, in addition to differences in responsiveness by species, genotype, and functional group. Previous studies on elevated CO2 responses in trees have either doubled the gas concentration (>700 μmol mol−1) or used single large addition of CO2 (500-600 μmol mol−1). In this study, Gmelina arborea, a fast growing tropical deciduous tree species, was selected to determine the photosynthetic efficiency, growth response and overall source-sink relations under near elevated atmospheric CO2 concentration (460 μmol mol−1). Net photosynthetic rate of Gmelina was ∼30% higher in plants grown in elevated CO2 compared with ambient CO2-grown plants. The elevated CO2 concentration also had significant effect on photochemical and biochemical capacities evidenced by changes in FV/FM, ABS/CSm, ET0/CSm and RuBPcase activity. The study also revealed that elevated CO2 conditions significantly increased absolute growth rate, above ground biomass and carbon sequestration potential in Gmelina which sequestered ∼2100 g tree−1 carbon after 120 days of treatment when compared to ambient CO2-grown plants. Our data indicate that young Gmelina could accumulate significant biomass and escape acclimatory down-regulation of photosynthesis due to high source-sink capacity even with an increase of 100 μmol mol−1 CO2. 相似文献
96.
97.
Sharma P Dube D Sinha M Mishra B Dey S Mal G Pathak KM Kaur P Sharma S Singh TP 《The Journal of biological chemistry》2011,286(36):31723-31730
The peptidoglycan recognition protein PGRP-S is an innate immunity molecule that specifically interacts with microbial peptidoglycans and other pathogen-associated molecular patterns. We report here two structures of the unique tetrameric camel PGRP-S (CPGRP-S) complexed with (i) muramyl dipeptide (MDP) at 2.5 Å resolution and (ii) GlcNAc and β-maltose at 1.7Å resolution. The binding studies carried out using surface plasmon resonance indicated that CPGRP-S binds to MDP with a dissociation constant of 10−7 m, whereas the binding affinities for GlcNAc and β-maltose separately are in the range of 10−4 m to 10−5 m, whereas the dissociation constant for the mixture of GlcNAc and maltose was estimated to be 10−6 m. The data from bacterial suspension culture experiments showed a significant inhibition of the growth of Staphylococcus aureus cells when CPGRP-S was added to culture medium. The ELISA experiment showed that the amount of MDP-induced production of TNF-α and IL-6 decreased considerably after the introduction of CPGRP-S. The crystal structure determinations of (i) a binary complex with MDP and (ii) a ternary complex with GlcNAc and β-maltose revealed that MDP, GlcNAc, and β-maltose bound to CPGRP-S in the ligand binding cleft, which is situated at the interface of molecules C and D of the homotetramer formed by four protein molecules A, B, C, and D. In the binary complex, the muramyl moiety of MDP is observed at the C-D interface, whereas the peptide chain protrudes into the center of tetramer. In the ternary complex, GlcNAc and β-maltose occupy distinct non-overlapping positions belonging to different subsites. 相似文献
98.
Sharmistha Choudhuri Chandresh Sharma Ayan Banerjee Sunesh Kumar Lalit Kumar Neeta Singh 《Molecular and cellular biochemistry》2014,386(1-2):259-269
In epithelial ovarian cancer (EOC), the cancer antigen 125 (CA-125) has been conventionally used to help in diagnosis and assessment of response to treatment. Currently, YKL-40 (Tyrosine–Lysine–Leucine-40) and circulating cell-free DNA are being evaluated for possession of similar ability. In this study, we aimed to assess the ability of a repertoire of potential biomarkers in detecting and assessing therapeutic response, in advanced EOC. Blood levels of CA-125, YKL-40, total cell-free DNA (CFDNA), cell-free nuclear DNA (CFnDNA), and cell-free mitochondrial DNA (CFmDNA) levels were measured in 100 untreated patients of advanced EOC from November 2009 to June 2011, and again on treatment completion from the 20 patients who appeared for follow-up analysis. Significantly, higher proportion of untreated patients had serum CA-125 >3 times upper limit of normal (ULN) (90.0 %; P < 0.0001) and plasma YKL-40 >ULN (77.0 %; P < 0.0001), both of which significantly decreased, Posttherapy. posttherapy, CFDNA (P < 0.0001), and CFnDNA (P < 0.0001) levels significantly decreased as compared to pretreatment levels. Positive and significant correlations existed between pretherapy CFDNA and CFnDNA [Spearman rho (ρ) = 1.000; P < 0.0001], and also with CFmDNA (ρ = 0.301; P = 0.002), separately between CFnDNA and CFmDNA (ρ = 0.303; P = 0.002), as well as between plasma YKL-40 and patient age (ρ = 0.353; (P < 0.0001). On treatment completion, CFDNA and CFnDNA levels showed positive and significant correlation (ρ = 1.000; P < 0.0001). Therefore serum CA-125 and plasma YKL-40 aid detection and assessment of therapeutic response, in advanced EOC. CFDNA and CFnDNA help in estimating extent of therapeutic response in advanced EOC. 相似文献
99.
The present study was undertaken to characterize leaf gas exchange physiology and photoacclimation characteristics in drought-stressed mulberry cultivar V1 (Morus indica L.) grown under the hot semi-arid steppe agroclimate of Southern India. The experiment was conducted in year 2009 during peak summer months (April–June). Mulberry plants, grown in short rotation coppice system, were subjected to two irrigation regimes: the control plot received a regulated full-rate irrigation (weekly 2–3 times) and the drought-stressed plot received a regulated deficit irrigation (irrigated only once in a fortnight). Net photosynthesis, transpiration, stomatal conductance, leaf water potential (ΨL) and photosytem-II (PS II) efficiency were examined. In spite of significant down-regulation in leaf gas exchange, the drought-stressed stands still exhibited a considerable rate of photosynthesis along with significant concomitant decrease in ΨL, more conspicuously during midday (12.00–13.00 h) depicting rather low stomatal control on ΨL, a behavior characterized as ‘anisohydric’. The PS II structural and functional integrity was well-maintained, even in the drought-stressed plants. However, apparent photoacclimatory changes were recorded in drought-exposed stands including decrease in electron transport and enhanced thermal dissipation from PS II. Overall, our data demonstrate some of the important driving leaf-level mechanisms adopted by mulberry cultivar V1 to tolerate drought stress and sustain photosynthesis. 相似文献
100.
Elisa Mountain Sharmistha Mishra Peter Vickerman Michael Pickles Charles Gilks Marie-Claude Boily 《PloS one》2014,9(9)