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21.
Plant growth promotion and suppression of charcoal‐rot fungus (Macrophomina phaseolina) in velvet bean (Mucuna pruriens L.) by root nodule bacteria 下载免费PDF全文
Abhinav Aeron Dinesh Kumar Maheshwari Shrivardhan Dheeman Mohit Agarwal Ramesh Chand Dubey Vivek K. Bajpai 《Journal of Phytopathology》2017,165(7-8):463-478
Root‐nodulating bacteria are intimate associates of legumes. From a pool of rhizobia isolated from root nodules of Mucuna pruriens (Velvet bean/Kaunch), RMP66 and BMP17 were found to be capable of promoting siderophore and IAA production and phosphate solubilization (insoluble tri‐calcium). Both symbionts were studied further to determine their abilities to promote plant growth and to control root‐rot in Mucuna pruriens caused by the pathogenic plant fungus Macrophomina phaseolina. RMP66 and BMP17 were selected based on their excellent inhibitory activities against M. phaseolina (by 78% and 71%, respectively) in dual culture and in agar‐well assays using cell‐free culture filtrate (CFCF) (by 76% and 62%, respectively). Both strains inhibited fungal growth to a greater extent in iron‐deficient medium (51% and 69%) than in iron‐supplemented medium (37% and 0%), respectively. CFCFs of RMP66 and BMP17 obtained from Pikovskaya's broth and tryptophan‐amended YEM broth inhibited fungal growth by 80%‐55% and 70%‐43%, respectively, and were identified as Sinorhizobium meliloti RMP66 and Bradyrhizobium diazoefficiens BMP17 by 16S rDNA sequencing. Centrifuged and pelleted cells harvested from exponentially grown cultures of S. meliloti RMP66 and B. diazoefficiens BMP17 were used to bacterize seeds of M. pruriens, which then showed enhanced seed germination (by up to 17% and 12%, respectively), and subsequent increases in other plant growth parameters in field trials. Considerable increases in seedling vigour indices (62%: 53% and 110%: 130%) and biomass (8%: 13% and 25%: 28%) were also observed for bacterial treatments. Tn5‐mediated antibiotic‐resistant marker strains showed enhanced nodule occupancy by up to 72% and 68%, respectively. This study describes a multifunctional legume nodule rhizobia that could be utilized in multicropping systems under different agroclimatic conditions as a bioinoculant and alternative to fertilizers. 相似文献
22.
Neutrophil specific chemokines are potent chemoattractants for neutrophils. IL-8/CXCL8 is the most extensively studied member of this group, and its concentrations increase during inflammatory conditions of the newborn infant including sepsis and chronic lung disease. A significant amount of information exists on the effects of IL-8/CXCL8 on neutrophil chemotaxis of neonates, but little is known about the other neutrophil specific chemokines. The aim of this study was to determine the relative potency of the neutrophil specific chemokines on chemotaxis of neonatal neutrophils and to compare this effect with the effect on adult neutrophils. Neutrophils were isolated from cord blood or healthy adult donors and incubated in a Neuroprobe chemotaxis chamber. Chemokine concentrations ranging from 1-1000 ng/mL were used. Differences in chemotactic potency existed among the seven neutrophil specific chemokines. Specifically, at 100 ng/mL, the order was IL-8/CXCL8>GRO-alpha/CXCL1>GCP-2/CXCL6>NAP-2/CXCL7>ENA-78/CXCL5>GRO-gamma/CXCL2>GRO-beta/CXCL3. This pattern was observed for adult and neonatal neutrophils. We conclude that (1) neutrophils from cord blood exhibit the same pattern of potency for each ELR chemokine as neutrophils from adults, and (2) migration of neonatal neutrophils is significantly less than that of adults at every concentration examined except the lowest (1 ng/mL). 相似文献
23.
Vijay K. Sharma Pradeep K. Jain Satish C. Maheshwari Jitendra P. Khurana 《Journal of plant biochemistry and biotechnology.》1999,8(2):87-92
The polypeptides of etioplast and chloroplast fractions, purified on Percoll discontinuous gradient, were phosphorylated in vitro using (γ-32P)ATP, resolved by SDS-PAGE and autoradiographed. In general, about 15-18 phosphopolypeptides in the range of 14-150 kD were distinctly visible in autoradiograms of both organelle fractions with varying degree of radiolabel incorporation. Although short-term irradiation with red or far-red light did not have any significant effect on phosphorylation status of etioplast polypeptides, in vivo irradiation with 1 h white light, followed by in vitro phosphorylation, decreased phosphorylation of a 116 kD polypeptide and increased the phosphorylation of polypeptides of 38 kD and a doublet around 20 kD. Strikingly, the phosphorylation status of 116 kD etioplast polypeptide was adversely affected by Ca2+ as well, and this phosphopolypeptlde was not distinctly visible in the autoradiogram of the chloroplast fraction proteins. However, in vitro phosphorylation of 98, 57 and 50 kD polypeptides of both etioplast and chloroplast fractions was found to be Ca2+ dependent. Unlike Ca2+, 3′,5′-cyclic AMP down-regulated the phosphorylation of several polypeptides of both etioplasts and chloroplasts, including 98 and 50 kD, and up-regulated the phosphorylation of 32 and 57 kD polypeptides. The significance of these observations on changes in phosphoprotein profile of etioplasts and chloroplasts, as influenced by light, Ca2+ and cyclic nucleotides, has been discussed. 相似文献
24.
Naseer Mohammad Ankur Dahayat Manorama Yadav Fatima Shirin S. A. Ansari 《Physiology and Molecular Biology of Plants》2018,24(4):655-663
Litsea glutinosa (Lour.), one of the most dwindling forest species in central India, is represented by highly fragmented populations that have been drastically reduced for the last 40 years, promulgating government ban on its extraction. For the first time with the help of ISSR markers, we investigated genetic variation and population structure of L. glutinosa in central Indian states. A total of 84 genotypes from 10 populations covering the entire potential pockets of the species in central India were collected. The percentage of polymorphic loci ranged from 44.79% (Rewa) to 94.79% (Marvahi) with a mean value of 70.10%. The sampled populations harbored high level of genetic diversity (mean h?=?0.294 and I?=?0.424) that was partitioned more within populations (73%) than between populations (27%). Bayesian structure analysis revealed the existence of four admixed genetic pools in L. glutinosa. The unsustainable extraction rather than genetic factor seems to be responsible for population fragmentation and dwindling status of this species. The dioecious nature of the species advocates an in-situ conservation to be the most suited approach for which Chhindwara, Jagdalpur, Balaghat and Jabalpur populations are appropriate. 相似文献
25.
Solar‐induced chlorophyll fluorescence is strongly correlated with terrestrial photosynthesis for a wide variety of biomes: First global analysis based on OCO‐2 and flux tower observations 下载免费PDF全文
Xing Li Jingfeng Xiao Binbin He M. Altaf Arain Jason Beringer Ankur R. Desai Carmen Emmel David Y. Hollinger Alisa Krasnova Ivan Mammarella Steffen M. Noe Penélope Serrano Ortiz A. Camilo Rey‐Sanchez Adrian V. Rocha Andrej Varlagin 《Global Change Biology》2018,24(9):3990-4008
Solar‐induced chlorophyll fluorescence (SIF) has been increasingly used as a proxy for terrestrial gross primary productivity (GPP). Previous work mainly evaluated the relationship between satellite‐observed SIF and gridded GPP products both based on coarse spatial resolutions. Finer resolution SIF (1.3 km × 2.25 km) measured from the Orbiting Carbon Observatory‐2 (OCO‐2) provides the first opportunity to examine the SIF–GPP relationship at the ecosystem scale using flux tower GPP data. However, it remains unclear how strong the relationship is for each biome and whether a robust, universal relationship exists across a variety of biomes. Here we conducted the first global analysis of the relationship between OCO‐2 SIF and tower GPP for a total of 64 flux sites across the globe encompassing eight major biomes. OCO‐2 SIF showed strong correlations with tower GPP at both midday and daily timescales, with the strongest relationship observed for daily SIF at the 757 nm (R2 = 0.72, p < 0.0001). Strong linear relationships between SIF and GPP were consistently found for all biomes (R2 = 0.57–0.79, p < 0.0001) except evergreen broadleaf forests (R2 = 0.16, p < 0.05) at the daily timescale. A higher slope was found for C4 grasslands and croplands than for C3 ecosystems. The generally consistent slope of the relationship among biomes suggests a nearly universal rather than biome‐specific SIF–GPP relationship, and this finding is an important distinction and simplification compared to previous results. SIF was mainly driven by absorbed photosynthetically active radiation and was also influenced by environmental stresses (temperature and water stresses) that determine photosynthetic light use efficiency. OCO‐2 SIF generally had a better performance for predicting GPP than satellite‐derived vegetation indices and a light use efficiency model. The universal SIF–GPP relationship can potentially lead to more accurate GPP estimates regionally or globally. Our findings revealed the remarkable ability of finer resolution SIF observations from OCO‐2 and other new or future missions (e.g., TROPOMI, FLEX) for estimating terrestrial photosynthesis across a wide variety of biomes and identified their potential and limitations for ecosystem functioning and carbon cycle studies. 相似文献
26.
Control of circadian rhythm in nitrate reductase activity in Wolffia microscopica Griff 总被引:1,自引:0,他引:1
Bakshi Inderjeet Singh; Farooqi A. H. Abad; Maheshwari S. C. 《Plant & cell physiology》1979,20(5):957-963
In Wolffia microscopica, the activity of nitrate reductase showedstrong diurnal rhythmicity with a peak in the forenoon. Therhythmicity persists under extended dark conditions as wellas under continuous light. The phase of the rhythm shifts underinverted light-dark cycles. Studies with various inhibitorsof macromolecular synthesis suggest that the increase in enzymeactivity depends on the new synthesis of both RNA and protein. (Received February 14, 1979; ) 相似文献
27.
Background
Although antiretroviral therapy (ART) is known to be associated with time-dependent reductions in tuberculosis (TB) incidence, the long-term impact of ART on incidence remains imprecisely defined due to limited duration of follow-up and incomplete CD4 cell count recovery in existing studies. We determined TB incidence in a South African ART cohort with up to 8 years of follow-up and stratified rates according to CD4 cell count recovery. We compared these rates with those of HIV-uninfected individuals living in the same community.Methodology/Principal Findings
Prospectively collected clinical data on patients receiving ART in a community-based cohort in Cape Town were analysed. 1544 patients with a median follow-up of 5.0 years (IQR 2.4–5.8) were included in the analysis. 484 episodes of incident TB (73.6% culture-confirmed) were diagnosed in 424 patients during 6506 person-years (PYs) of follow-up. The TB incidence rate during the first year of ART was 12.4 (95% CI 10.8–14.4) cases/100PYs and decreased to 4.92 (95% CI 3.64–8.62) cases/100PYs between 5 and 8 years of ART. During person-time accrued within CD4 cell strata 0–100, 101–200, 201–300, 301–400, 401–500, 501–700 and ≥700 cells/µL, TB incidence rates (95% CI) were 25.5 (21.6–30.3), 11.2 (9.4–13.5), 7.9 (6.4–9.7), 5.0 (3.9–6.6), 5.1 (3.8–6.8), 4.1 (3.1–5.4) and 2.7 (1.7–4.5) cases/100PYs, respectively. Overall, 75% (95% CI 70.9–78.8) of TB episodes were recurrent cases. Updated CD4 cell count and viral load measurements were independently associated with long-term TB risk. TB rates during person-time accrued in the highest CD4 cell count stratum (>700 cells/µL) were 4.4-fold higher that the rate in HIV uninfected individuals living in the same community (2.7 versus 0.62 cases/100PYs; 95%CI 0.58–0.65).Conclusions/Significance
TB rates during long-term ART remained substantially greater than rates in the local HIV uninfected populations regardless of duration of ART or attainment of CD4 cell counts exceeding 700 cells/µL. 相似文献28.
Green tea constituent epigallocatechin-3-gallate inhibits angiogenic differentiation of human endothelial cells 总被引:3,自引:0,他引:3
Singh AK Seth P Anthony P Husain MM Madhavan S Mukhtar H Maheshwari RK 《Archives of biochemistry and biophysics》2002,401(1):29-37
Several independent research studies have shown that consumption of green tea reduces the development of cancer in many animal models. Epidemiological observations, though inconclusive, are suggesting that green tea consumption may also reduce the risk of some cancers in humans. These anti-carcinogenic effects of green tea have been attributed to its constituent polyphenols. Angiogenesis is a crucial step in the growth and metastasis of cancers. We have investigated the effect of the major polyphenolic constituent of green tea, epigallocatechin-3-gallate (EGCG), on the tube formation of human umbilical vein endothelial cells (HUVEC) on matrigel. Tube formation was inhibited by treatment both prior to plating and after plating endothelial cells on matrigel. EGCG treatment also was found to reduce the migration of endothelial cells in matrigel plug model. The role of matrix metalloproteinases (MMP) has been shown to play an important role during angiogenesis. Zymography was performed to determine if EGCG had any effect on MMPs. Zymographs of EGCG-treated culture supernatants modulated the gelatinolytic activities of secreted proteinases indicating that EGCG may be exerting its inhibitory effect by regulating proteinases. These findings suggest that EGCG acts as an angiogenesis inhibitor by modulating protease activity during endothelial morphogenesis. 相似文献
29.
In Neurospora crassa, multinucleate macroconidia are used for genetic transformation. The barrier for such a transformation can be either at the
cell membrane level or at the nuclear membrane level. For assessment of these possibilities, a forced heterokaryon (containing
two genetically marked nuclei and auxotrophic for histidine) of Neurospora crassa was transformed with a plasmid containing his-3
+ gene. The transformants, which could grow without histidine supplementation, were then resolved into component homokaryons
to determine into which nucleus or nuclei the plasmid had entered. Our results suggest that the barrier for transformation
in Neurospora crassa is at the nuclear level, not at the cell membrane level. In a heterokaryon containing two genetically distinct nuclei, plasmid
DNA integrated into only one of the nuclear types at any instance, but never into both nuclear types. Thus, in Neurospora crassa, the competent nucleus is essential for the transformation event to take place, and at a given time only one type of nucleus
is competent to take up the exogenous DNA. Genomic Southern analysis showed that the transformants harbor both ectopic and
homologous integrations of the plasmid DNA. The type and number of integrations were reflected at the post-translational level,
since the specific activity of histidinol dehydrogenase (the translation product of his-3
+ gene) was variable among several transformants and always less than the level of the wild type.
Received: 24 July 2001 / Accepted: 15 August 2001 相似文献
30.
Amelt solidification technique has been developed to obtain sustained-release waxy beads of flurbiprofen. Low glass transition
temperature (t
g) and shear-induced crystallization of flurbiprofen made it a suitable candidate for melt solidification technique. The process
involved emulsification and solidification of flurbiprofen-cetyl alcohol melt at significantly low temperature (5°C). The
effect of variables, namely, the amount of cetyl alcohol and the speed of agitation, was studied using 32 factorial design. The technique and the beads were evaluated on the basis of process and desired yield, surface topography,
Fourier-transform infrared (FT-IR), differential scanning calorimetry (DSC), particle size distribution, crushing strength,
and drug release. Average values for process and desired yields were 97% wt/wt and 26% wt/wt, respectively. No interaction
was observed between drug and excipient. Multiple regression analysis was carried out, and response surfaces were obtained.
A curvilinear relationship was observed between percentage of desired yield and the amount of cetyl alcohol. Linear decrease
in crushing strength was observed with increase in the amount of cetyl alcohol. Drug released from the beads followed zero
order kinetics. Burst release was shown to a greater extent in beads containing a lower amount of cetyl alcohol. Response
surfaces of time required for certain percentage of drug (t
D%) showed that after critical concentration of about 20% of cetyl alcohol (400 mg/batch), no significant release retardant
effect was observed. 相似文献