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Extraction, thin-layer chromatography, and gas chromatography–mass spectrometry of leaf surface waxes of Momordica charantia L. (Cucurbitaceae) revealed that 20 n-alkanes between n-C15 and n-C36, except n-C34 and n-C35, commonly occur in young, mature, and senescent stages. Hentriacontane, hentriacontane, and hexatriacontane were the predominant compounds in young, mature, and senescent leaves, respectively. The cuticular alkanes from young, mature, and senescent leaves attracted the female insect, Epilachna dodecastigma (Wied.), at 25–400, 25–400, and 100–400 μg concentrations, respectively, whereas the mixtures of synthetic alkanes mimicking cuticular alkanes of young, mature, and senescent leaves showed attraction at 100–400, 100–400, and 200–400 μg concentrations, respectively, in Y-shaped glass tube olfactometer bioassay. The difference in insect attraction is probably due to the absence of branched-chain alkanes in the synthetic mixtures. Individual synthetic heptacosane, nonacosane, and hentriacontane at 28.19–56.90, 32.04–64.08, and 60.44–120.88 μg, respectively, elicited attraction of the insect. A synthetic blend of 4.82, 4.91, 5.71, 6.74, 56.39, 7.94, 62.42, 120.88, and 36.33 μg of nonadecane, eicosane, heneicosane, pentacosane, heptacosane, octacosane, nonacosane, hentriacontane, and tritriacontane, respectively, was most attractive to the insect. 相似文献
23.
Molecular techniques play a critical role in studies of phylogeny and, thus, have been applied to understand the distribution and extent of genetic variation within and between species. In the present study, a genetic analysis was undertaken using molecular markers (9 ISSR and 13 SSR) on 60 ginger cultivars from different regions of the eastern coast of India (Odisha). The data obtained with 22 polymorphic markers revealed moderate to high diversity in the collection. Both ISSR and SSR markers were efficient in distinguishing all the 60 ginger cultivars. A total of 42 and 160 polymorphic bands were observed with ISSR and SSR markers, respectively. However, SSR markers were observed to be better at displaying average polymorphism (63.29%) than ISSR markers (55%). Analysis of molecular variance results showed that 52 and 66% of the variation occurred among different ginger populations, whereas 48 and 34% of the variation was found within populations, respectively, using ISSR and SSR markers, indicating that ginger cultivars display significant genetic diversity at the population level. Principal coordinates analysis and the dendrogram constructed out of combined data of both markers showed grouping of ginger accessions to their respective area of collection, indicating geographical closeness due to genetic similarity irrespective of the relationship that exists at the morphological level. 相似文献
24.
Many physiological characteristics of living cells are regulated by protein interaction networks. Because the total numbers of these protein species can be small, molecular noise can have significant effects on the dynamical properties of a regulatory network. Computing these stochastic effects is made difficult by the large timescale separations typical of protein interactions (e.g., complex formation may occur in fractions of a second, whereas catalytic conversions may take minutes). Exact stochastic simulation may be very inefficient under these circumstances, and methods for speeding up the simulation without sacrificing accuracy have been widely studied. We show that the “total quasi-steady-state approximation” for enzyme-catalyzed reactions provides a useful framework for efficient and accurate stochastic simulations. The method is applied to three examples: a simple enzyme-catalyzed reaction where enzyme and substrate have comparable abundances, a Goldbeter-Koshland switch, where a kinase and phosphatase regulate the phosphorylation state of a common substrate, and coupled Goldbeter-Koshland switches that exhibit bistability. Simulations based on the total quasi-steady-state approximation accurately capture the steady-state probability distributions of all components of these reaction networks. In many respects, the approximation also faithfully reproduces time-dependent aspects of the fluctuations. The method is accurate even under conditions of poor timescale separation. 相似文献
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Yadav Shweta Gupta Ekta Patel Anju Srivastava Suchi Mishra Virendra Kumar Singh Poonam C. Srivastava Pankaj Kumar Barik Saroj Kanta 《Reviews in Environmental Science and Biotechnology》2022,21(3):771-798
Reviews in Environmental Science and Bio/Technology - In the past few decades, pollution from microplastics has emerged as an important issue on a global scale. These plastic particles are mainly... 相似文献
27.
Partha Mukherjee Kamakshi Sureka Pratik Datta Tofajjen Hossain Subhasis Barik Kali P. Das Manikuntala Kundu Joyoti Basu 《Molecular microbiology》2009,73(1):103-119
Wag31 of Mycobacterium tuberculosis belongs to the DivIVA family of proteins known to regulate cell morphology in Gram-positive bacteria. Here we demonstrate an unrecognized, novel role of Wag31 in oxidatively stressed mycobacteria. We report the cleavage of penicillin-binding protein 3 (PBP3) by the intramembrane metalloprotease Rv2869c (MSMEG_2579) in oxidatively stressed cells. Amino acids 102 A and 103 A of PBP3 are required for Rv2869c-mediated cleavage. Wag31MTB , by virtue of its interaction with PBP3 through amino acid residues 46 NSD48 , protects it from oxidative stress-induced cleavage. PBP3 undergoes cleavage in Mycobacterium smegmatis (strain PM2) harbouring wag31 (Δ46 NSD48 ) instead of the wild type, with concomitant reduction in ability to withstand oxidative stress. Overexpression of Wag31(Δ46 NSD48 ) attenuates the survival of M. tuberculosis in macrophages with concomitant cleavage of PBP3, and renders the organism more susceptible towards hydrogen peroxide as well as drugs which generate reactive oxygen species, namely isoniazid and ofloxacin. We propose that targeting Wag31 could enhance the activity of mycobactericidal drugs which are known to generate reactive oxygen species. 相似文献
28.
Barik S 《Journal of biosciences》2004,29(3):261-273
The significance of the intron-exon structure of genes is a mystery. As eukaryotic proteins are made up of modular functional
domains, each exon was suspected to encode some form of module; however, the definition of a module remained vague. Comparison
of pre-mRNA splice junctions with the three-dimensional architecture of its protein product from different eukaryotes revealed
that the junctions were far less likely to occur inside the α-helices and Β-strands of proteins than within the more flexible
linker regions (‘turns’ and ‘loops’) connecting them. The splice junctions were equally distributed in the different types
of linkers and throughout the linker sequence, although a slight preference for the central region of the linker was observed.
The avoidance of the α-helix and the (Β-strand by splice junctions suggests the existence of a selection pressure against
their disruption, perhaps underscoring the investment made by nature in building these intricate secondary structures. A corollary
is that the helix and the strand are the smallest integral architectural units of a protein and represent the minimal modules
in the evolution of protein structure. These results should find use in comparative genomics, designing of cloning strategies,
and in the mutual verification of genome sequences with protein structures. 相似文献
29.
Human ribosomal protein L13a is dispensable for canonical ribosome function but indispensable for efficient rRNA methylation 下载免费PDF全文
Chaudhuri S Vyas K Kapasi P Komar AA Dinman JD Barik S Mazumder B 《RNA (New York, N.Y.)》2007,13(12):2224-2237
Previously, we demonstrated that treatment of monocytic cells with IFN-gamma causes release of ribosomal protein L13a from the 60S ribosome and subsequent translational silencing of Ceruloplasmin (Cp) mRNA. Here, evidence using cultured cells demonstrates that Cp mRNA silencing is dependent on L13a and that L13a-deficient ribosomes are competent for global translational activity. Human monocytic U937 cells were stably transfected with two different shRNA sequences for L13a and clonally selected for more than 98% abrogation of total L13a expression. Metabolic labeling of these cells showed rescue of Cp translation from the IFN-gamma mediated translational silencing activity. Depletion of L13a caused significant reduction of methylation of ribosomal RNA and of cap-independent translation mediated by Internal Ribosome Entry Site (IRES) elements derived from p27, p53, and SNAT2 mRNAs. However, no significant differences in the ribosomal RNA processing, polysome formation, global translational activity, translational fidelity, and cell proliferation were observed between L13a-deficient and wild-type control cells. These results support the notion that ribosome can serve as a depot for releasable translation-regulatory factors unrelated to its basal polypeptide synthetic function. Unlike mammalian cells, the L13a homolog in yeast is indispensable for growth. Thus, L13a may have evolved from an essential ribosomal protein in lower eukaryotes to having a role as a dispensable extra-ribosomal function in higher eukaryotes. 相似文献
30.
Syed Husne Mobarak Anamika Koner Saubhik Mitra Paroma Mitra Anandamay Barik 《Journal of Applied Entomology》2020,144(7):616-631
Green gram, Vigna radiata (L.) Wilczek, is an important pulse crop of Asia. Severe attack by the larvae of Spilosoma obliqua Walker (Lepidoptera: Arctiidae) causes defoliation of green gram and reduces seed yield. Females lay eggs on the leaf surface, and therefore, surface wax plays an important role as short-range attractant and oviposition stimulant. So, we have attempted to find out whether leaf surface wax compounds (alkanes and free fatty acids) from three green gram cultivars (PDM 54, PUSA BAISAKHI and SAMRAT) could act as short-range attractant and oviposition stimulant in females. The TLC, GC-MS and GC-FID analyses of n-hexane extracts revealed 20 n-alkanes from n-C15 to n-C36 and 13 free fatty acids from C12:0 to C21:0, whilst linoleic acid was unique in SAMRAT. Pentacosane was the predominant amongst n-alkanes in the leaf surface waxes of three cultivars. Heneicosanoic acid and palmitoleic acid were the predominant free fatty acids in the leaf surface waxes of PDM 54, and PUSA BAISAKHI and SAMRAT, respectively. Females were attracted towards one leaf equivalent surface wax of three green gram cultivars against solvent controls (n-hexane) in Y-tube olfactometer bioassays. A synthetic blend of pentacosane, heptacosane, nonacosane, hexatriacontane, palmitoleic acid, linolenic acid and stearic acid, a synthetic blend of pentacosane, hexatriacontane and stearic acid, and a synthetic blend of hexatriacontane, linolenic acid and stearic acid resembling in amounts present in one leaf equivalent surface wax of PDM 54, PUSA BAISAKHI and SAMRAT, respectively, served as short-range attractant and oviposition stimulant in females. Females showed equal preference for egg laying towards the above three synthetic blends when these blends were tested against each other, and hence, these blends could be employed in development of baited traps in pest management strategies. 相似文献