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991.
A laboratory study was undertaken to ascertain the impact and the extent of feeding by different pests on biochemical constituents
and various enzyme levels in rice plants. The difference in these parameters due to the pest damage by three different modes
of feeding was also studied and compared. The borer pest—yellow stem borer (YSB), Scirpophaga incertulas (W); surface feeder—-leaf roller (LR), Cnaphalocrosis medinalis (G) and a sucking pest—brown plant hopper (BPH), Nilaparvata lugens (S) fed rice plants were analyzed for the quantitative and qualitative changes in biochemical profile and enzymatic changes
that occur as plant’s defensive responses were analyzed spectrophotometrically. The phenolic acids were analyzed using HPLC
and quantitated with the standard samples. The quantity of biochemicals such as proteins, phenols and carbohydrates has been
enhanced along with the enzyme activities of peroxidase (POD), catalase (CAT), chitinase (CHI). A decrease in superoxide dismutase
(SOD), phenyl alanine ammonia lyase (PAL), β-1, 3-glucanase (GLU) enzyme activities were evident in pest infested plants.
Phenolic acids like vanillic acid, syringic acid, cinnamic acid, and p-coumaric acids were mostly found in the infested plants. We demonstrate that the elevated levels of biochemicals, phenolic
acids, and enzymes may play a major role in plant defense. 相似文献
992.
G. Sangeetha R. Thangavelu S. Usha Rani A. Muthukumar R. Udayakumar 《Acta Physiologiae Plantarum》2010,32(6):1177-1187
Among nine native bacterial strains isolated from banana fruit surface and rhizosphere and six bacterial strains introduced
from the culture collection, three native strains viz., non-fluorescent Pseudomonas (NFP6), Pseudomonas fluorescens (Pf3a), and Bacillus subtilis (BS1); and two bacterial strains from culture collection viz., Azospirillum (AS1) and Azotobacter (AZ1) have recorded maximum inhibition of mycelial growth of crown rot pathogens (Lasiodiplodia theobromae and Colletotrichum musae) under in vitro condition. When these effective bacterial strains were treated on banana fruits under in vivo, significant
reduction of crown rot disease and increased shelf life of banana was observed. However, bacterial strains applied as three
way combinations (NFP6 + Pf3a + BS1) had greater effect compared with individual and two way combination of bacterial antagonist treatments. The effect of crown
rot disease reduction was also comparable to that of fungicide Benomyl (0.1%) both under cold and room temperature storage
conditions. Besides, the induction of defense-related enzymes such as phenylalanine ammonia-lyase (PAL), peroxidase (PO),
polyphenoloxidase (PPO), and the accumulation of phenolics in banana fruit due to the application of bacterial antagonists
were also studied at five different time intervals viz. 0th, 1st, 3rd, 5th and 7th days after treatment. When banana fruits
treated with bacterial antagonists (individually and also in different combinations) and challenge-inoculated with crown rot
pathogens, up to fourfold increase in defense-related enzymes and 3.6 fold increase in phenolic content was observed compared
with control. The activity of these defense-related enzymes and phenolic content had gradually increased from 1st day after
treatment to 3rd after treatment and reached their peak on 5th day after treatment. Among the bacterial antagonists which
have been applied individually and in different combinations, the banana fruits treated with three-way antagonist mixture,
i.e., NFP6 + Pf3a + BS1 recorded maximum induction of defense-related enzymes and accumulation of phenolics compared with individual and two-way
combination of antagonist mixtures. This study suggest that the increased induction of defense-related enzymes and phenolic
content due to the treatment of banana fruits with bacterial antagonists might have involved in the reduction of crown rot
severity and in turn increased the shelf life of banana fruits. 相似文献
993.
Apoplasmic assimilates and grain growth of contrasting rice cultivars differing in grain dry mass and size 总被引:1,自引:0,他引:1
Sandhya Rani Kuanar Rashmi Panigrahi Ekamber Kariali Pravat Kumar Mohapatra 《Plant Growth Regulation》2010,61(2):135-151
Apical dominance in assimilate filling impacts grain growth in basal spikelets of rice panicle. In this study, organic materials
of the pericarp, apoplasmic space and endosperm of the apical and basal caryopses, and photosynthesis of the flag leaf were
measured during early part of grain development in three types of rice cultivars with similar phenology, but difference in
grain weight and size in the dry and wet seasons of 2006 and 2007, respectively. Photosynthetic activity of the flag leaf
was consistently low in small-seeded cultivars. Rates of grain filling and cell division of endosperm and concentration of
assimilates, starch, proteins and chlorophylls of the caryopsis were lower, but spikelet ethylene production and peroxidase
activity were higher in a small-seeded cultivar compared to a big-seeded cultivar. Similar disparities in grain filling and
other attributes were noticed for the inferior basal spikelets of the panicle compared to the superior apical spikelets, except
the assimilate concentration of the pericarp and endosperm. Temporal fluctuation in assimilate concentration of the organs
were similar between the cultivars. Concentration of apoplasmic assimilates mostly exhibited negative correlation with that
of pericarp and endosperm. Compared to the apical spikelets, correlation was more negative for the basal spikelets. Conversely,
correlation was positive between the concentration of apoplasmic assimilates and endosperm cell number and grain weight of
the cultivars. Ethylene released from the spikelets at anthesis affected growth and cell division rates of endosperm and enhanced
protein and chlorophyll degradation and peroxidase activity of the caryopsis. It was concluded that variation in spikelet
ethylene production may be responsible for differences in size or weight of grains among rice cultivars and spikelets at different
locations of the panicle. The concentration of apoplasmic assimilates could be an indicator for grain filling capacity, and
ethylene regulated the concentration by affecting pericarp activity for assimilate unloading. 相似文献
994.
The early expression of Epap-1 (early pregnancy associated protein), a 90 kDa anti-HIV-1 active glycoprotein, in the first trimester placental tissue suggests that it is one of the innate immune factors/proteins protecting the fetus from HIV infections. In the present investigation, we have cloned and expressed Epap-1 in bacterial and baculovirus expression systems. The recombinant Epap-1 as well as native Epap-1 shows a conserved molecular mode of action. These proteins exhibit significant antiviral activity and inhibit the cell fusion reaction between gp120 expressing HeLa (HL2/3) cells and T cell line (SupT1). Further, the rhodamine labeled Epap-1 specifically bound to gp120 expressed on the surface of HL2/3 cells during fusion reaction thereby inhibiting viral entry. Analysis of the interacting gp120 epitopes revealed that Epap-1 binds specifically to epitopes of gp120, recognizing constant-5 (C5) region and the variable-3 (V3) epitope of gp120 expressed on HL2/3 cells; It exhibits specific interaction with C5 region of cell-free virus in four HIV-1 isolates suggesting that the molecular interaction of Epap-1 is specific and is highly conserved in binding to gp120 leading to inhibition of viral entry. Epap-1 can thus be a very efficient natural protection mechanism against cell-free and cell-associated viral infections during early pregnancy. 相似文献
995.
Roumenina LT Ruseva MM Zlatarova A Ghai R Kolev M Olova N Gadjeva M Agrawal A Bottazzi B Mantovani A Reid KB Kishore U Kojouharova MS 《Biochemistry》2006,45(13):4093-4104
C1q is the first subcomponent of the classical complement pathway that can interact with a range of biochemically and structurally diverse self and nonself ligands. The globular domain of C1q (gC1q), which is the ligand-recognition domain, is a heterotrimeric structure composed of the C-terminal regions of A (ghA), B (ghB), and C (ghC) chains. The expression and functional characterization of ghA, ghB, and ghC modules have revealed that each chain has specific and differential binding properties toward C1q ligands. It is largely considered that C1q-ligand interactions are ionic in nature; however, the complementary ligand-binding sites on C1q and the mechanisms of interactions are still unclear. To identify the residues on the gC1q domain that are likely to be involved in ligand recognition, we have generated a number of substitution mutants of ghA, ghB, and ghC modules and examined their interactions with three selected ligands: IgG1, C-reactive protein (CRP), and pentraxin 3 (PTX3). Our results suggest that charged residues belonging to the apex of the gC1q heterotrimer (with participation of all three chains) as well as the side of the ghB are crucial for C1q binding to these ligands, and their contribution to each interaction is different. It is likely that a set of charged residues from the gC1q surface participate via different ionic and hydrogen bonds with corresponding residues from the ligand, instead of forming separate binding sites. Thus, a recently proposed model suggesting the rotation of the gC1q domain upon ligand recognition may be extended to C1q interaction with CRP and PTX3 in addition to IgG1. 相似文献
996.
Dichek HL Agrawal N El Andaloussi N Qian K 《American journal of physiology. Endocrinology and metabolism》2006,290(5):E908-E915
Hepatic lipase (HL), a liver-expressed lipolytic enzyme, hydrolyzes triglycerides and phospholipids in lipoproteins and promotes cholesterol delivery through receptor-mediated whole particle and selective cholesterol uptake. HL activity also occurs in the adrenal glands, which utilize lipoprotein cholesterol to synthesize glucocorticoids in response to pituitary ACTH. It is likely that the role of adrenal HL is to facilitate delivery of exogenous cholesterol for glucocorticoid synthesis. On this basis, we hypothesized that HL deficiency would blunt the glucocorticoid response to ACTH. Furthermore, because exogenous cholesterol also is derived from the LDL receptor (LDLR) pathway, we hypothesized that LDLR deficiency would blunt the response to ACTH. To test these hypotheses, we compared the corticosterone response to eight daily ACTH injections in HL-deficient (hl-/-), LDLR-deficient (Ldlr-/-), and HL- and LDLR-doubly deficient (Ldlr-/- hl-/-) mice with that in wild-type (WT) mice. Plasma corticosterone levels were measured on days 2, 5, and 8. Differences in plasma corticosterone levels between genotypes were analyzed by Kruskal-Wallis one-way ANOVA on ranks and pairwise multiple comparisons by Dunn's test. Our results demonstrate a trend toward reductions in plasma corticosterone levels on day 2 and significant reductions on day 5 and day 8 in the knockout models. Thus, on day 5, plasma corticosterone levels were reduced by 57, 70, and 73% (all P < 0.05) and on day 8 by 76, 59, and 63% (all P < 0.05) in hl-/-, Ldlr-/-, and Ldlr-/- hl-/- mice, respectively. These results demonstrate that HL deficiency, like LDLR deficiency, blunts the adrenal response to chronic ACTH stimulation and suggest a novel role for HL in adrenal physiology. 相似文献
997.
The complete primary structure of the hyn-region in the genome of Desulfovibrio vulgaris Miyazaki F (DvMF), encoding the [NiFe]-hydrogenase and two maturation proteins has been identified. Besides the formerly reported genes for the large and small subunits, this region comprises genes encoding an endopeptidase (HynC) and a putative chaperone (HynD). The complete genomic region covers 4086 nucleotides including the previously published upstream located promoter region and the sequences of the structural genes. A phylogenetic tree for both maturation proteins shows strongest sequential relationship to the orthologous proteins of Desulfovibrio vulgaris Hildenborough (DvH). Secondary structure prediction for HynC (168 aa, corresponding to a molecular weight of 17.9 kDa) revealed a practically identical arrangement of α-helical and β-strand elements between the orthologous protein HybD from E. coli and allowed a three-dimensional modelling of HynC on the basis of the formerly published structure of HybD. The putative chaperone HynD consists of 83 aa (molecular weight of 9 kDa) and shows 76% homology to DvH HynD. Preliminary experiments demonstrate that the operon is expressed under the control of its own promoter in Escherichia coli, although no further processing could be observed, providing evidence that additional proteins have to be involved in the maturation process. Accession numbers: DQ072852, HynC protein ID AAY90127, HynD protein ID AAY90128. 相似文献
998.
Plant phosphoproteomics: a long road ahead 总被引:3,自引:0,他引:3
Phosphoproteomics can be defined as the comprehensive study of protein phosphorylation by identification of the phosphoproteins, exact mapping of the phosphorylation sites, quantification of phosphorylation, and eventually, revealing their biological function. Its place in today's research is vitally important to address the most fundamental question - how the phosphorylation events control most, if not all, of the cellular processes in a given organism? Despite the immense importance of phosphorylation, the analysis of phosphoproteins on a proteome-wide scale remains a formidable challenge. Nevertheless, several technologies have been developed, mostly in yeast and mammals, to conduct a large-scale phosphoproteomic study. Some of these technologies have been successfully applied to plants with a few modifications, resulting in documentation of phosphoproteins, phosphorylation site mapping, identification of protein kinase substrates, etc. at the global level. In this review, we summarize in vitro and in vivo approaches for detection and analysis of phosphoproteins including protein kinases and we discuss the importance of phosphoproteomics in understanding plant biology. These approaches along with bioinformatics will help plant researchers to design and apply suitable phosphoproteomic strategies in helping to find answers to their biological questions. 相似文献
999.
Fat and Wingless signaling oppositely regulate epithelial cell-cell adhesion and distal wing development in Drosophila 总被引:1,自引:0,他引:1
Development of organ-specific size and shape demands tight coordination between tissue growth and cell-cell adhesion. Dynamic regulation of cell adhesion proteins thus plays an important role during organogenesis. In Drosophila, the homophilic cell adhesion protein DE-Cadherin (DE-Cad) regulates epithelial cell-cell adhesion at adherens junctions (AJs). Here, we show that along the proximodistal (PD) axis of the developing wing epithelium, apical cell shapes and expression of DE-Cad are graded in response to Wingless (Wg), a morphogen secreted from the dorsoventral (DV) organizer in distal wing, suggesting a PD gradient of cell-cell adhesion. The Fat (Ft) tumor suppressor, by contrast, represses DE-Cad expression. In genetic tests, ft behaves as a suppressor of Wg signaling. Cytoplasmic pool of beta-catenin/Arm, the intracellular transducer of Wg signaling, is negatively correlated with the activity of Ft. Moreover, unlike that of Wg, signaling by Ft negatively regulates the expression of Distalless (Dll) and Vestigial (Vg). Finally, we show that Ft intersects Wnt/Wg signaling, downstream of the Wg ligand. Fat and Wg signaling thus exert opposing regulation to coordinate cell-cell adhesion and patterning along the PD axis of Drosophila wing. 相似文献
1000.
A new series of 8-(1-aryl-vinyl)-6,7,10-trioxaspiro [4.5] decanes 7a-e and 3-(1-aryl-vinyl)-l,2,5-trioxaspiro [5.5] undecanes 8a-e have been prepared and screened against multi-drug resistant Plasmodium yoelii in mice. 8-(1-Naphthalen-2-yl-vinyl)-6,7,10-trioxaspiro [4.5] decane 7b, the most active trioxane of the series, has also shown promising activity against Plasmodium cynomolgi in rhesus monkeys. 相似文献