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Dheeraj Verma Shuangxia Jin Anderson Kanagaraj Nameirakpam D. Singh Jaiyanth Daniel Pappachan E. Kolattukudy Michael Miller Henry Daniell 《PloS one》2013,8(2)
In order to produce low-cost biomass hydrolyzing enzymes, transplastomic lines were generated that expressed cutinase or swollenin within chloroplasts. While swollenin expressing plants were homoplasmic, cutinase transplastomic lines remained heteroplasmic. Both transplastomic lines showed interesting modifications in their phenotype, chloroplast structure, and functions. Ultrastructural analysis of chloroplasts from cutinase- and swollenin-expressing plants did not show typical lens shape and granal stacks. But, their thylakoid membranes showed unique scroll like structures and chloroplast envelope displayed protrusions, stretching into the cytoplasm. Unusual honeycomb structures typically observed in etioplasts were observed in mature chloroplasts expressing swollenin. Treatment of cotton fiber with chloroplast-derived swollenin showed enlarged segments and the intertwined inner fibers were irreversibly unwound and fully opened up due to expansin activity of swollenin, causing disruption of hydrogen bonds in cellulose fibers. Cutinase transplastomic plants showed esterase and lipase activity, while swollenin transplastomic lines lacked such enzyme activities. Higher plants contain two major galactolipids, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), in their chloroplast thylakoid membranes that play distinct roles in their structural organization. Surprisingly, purified cutinase effectively hydrolyzed DGDG to MGDG, showing alpha galactosidase activity. Such hydrolysis resulted in unstacking of granal thylakoids in chloroplasts and other structural changes. These results demonstrate DGDG as novel substrate and function for cutinase. Both MGDG and DGDG were reduced up to 47.7% and 39.7% in cutinase and 68.5% and 67.5% in swollenin expressing plants. Novel properties and functions of both enzymes reported here for the first time should lead to better understanding and enhanced biomass hydrolysis. 相似文献
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Sasikumar Arunachalam Palaniyandi Seung Hwan Yang Lixin Zhang Joo-Won Suh 《Applied microbiology and biotechnology》2013,97(22):9621-9636
Biological control and plant growth promotion by plant beneficial microbes has been viewed as an alternative to the use of chemical pesticides and fertilizers. Bacteria and fungi that are naturally associated with plants and have a beneficial effect on plant growth by the alleviation of biotic and abiotic stresses were isolated and developed into biocontrol (BCA) and plant growth-promoting agents (PGPA). Actinobacteria are a group of important plant-associated spore-forming bacteria, which have been studied for their biocontrol, plant growth promotion, and interaction with plants. This review summarizes the effects of actinobacteria as BCA, PGPA, and its beneficial associations with plants. 相似文献
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Promoter-trapping in Saccharomyces cerevisiae by radiation-assisted fragment insertion 总被引:1,自引:0,他引:1
Kiechle M Manivasakam P Eckardt-Schupp F Schiestl RH Friedl AA 《Nucleic acids research》2002,30(24):e136
Non-homologous insertion (NHI) of DNA fragments into genomic DNA is a method widely used in insertional mutagenesis screens. In the yeast Saccharomyces cerevisiae, the efficiency of NHI is very low. Here we report that its efficiency can be increased by γ-irradiation of recipient cells at the time of transformation. Radiation-assisted NHI depends on YKU70, but its efficiency is not improved by inactivation of RAD5 or RAD52. In a pilot study, we generated 102 transformant clones expressing a lacZ reporter gene under standard conditions (30°C, rich medium). The site of insertion was determined in a subset of eight clones in which lacZ expression was altered by UV-irradiation. A comparison with published data revealed that three of the eight genes identified in our screen have not been targeted by large-scale transposon-based insertion screens. This suggests that radiation-assisted NHI offers a more homogeneous coverage of the genome than methods relying on transposons or retroviral elements. 相似文献
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Fine Mapping QTL for Drought Resistance Traits in Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) Using Bulk Segregant Analysis 总被引:1,自引:0,他引:1
Salunkhe AS Poornima R Prince KS Kanagaraj P Sheeba JA Amudha K Suji KK Senthil A Babu RC 《Molecular biotechnology》2011,49(1):90-95
Drought stress is a major limitation to rice (Oryza sativa L.) yields and its stability, especially in rainfed conditions. Developing rice cultivars with inherent capacity to withstand
drought stress would improve rainfed rice production. Mapping quantitative trait loci (QTLs) linked to drought resistance
traits will help to develop rice cultivars suitable for water-limited environments through molecular marker-assisted selection
(MAS) strategy. However, QTL mapping is usually carried out by genotyping large number of progenies, which is labour-intensive,
time-consuming and cost-ineffective. Bulk segregant analysis (BSA) serves as an affordable strategy for mapping large effect
QTLs by genotyping only the extreme phenotypes instead of the entire mapping population. We have previously mapped a QTL linked
to leaf rolling and leaf drying in recombinant inbred (RI) lines derived from two locally adapted indica rice ecotypes viz., IR20/Nootripathu using BSA. Fine mapping the QTL will facilitate its application in MAS. BSA was done
by bulking DNA of 10 drought-resistant and 12 drought-sensitive RI lines. Out of 343 rice microsatellites markers genotyped,
RM8085 co-segregated among the RI lines constituting the respective bulks. RM8085 was mapped in the middle of the QTL region
on chromosome 1 previously identified in these RI lines thus reducing the QTL interval from 7.9 to 3.8 cM. Further, the study
showed that the region, RM212–RM302–RM8085–RM3825 on chromosome 1, harbours large effect QTLs for drought-resistance traits
across several genetic backgrounds in rice. Thus, the QTL may be useful for drought resistance improvement in rice through
MAS and map-based cloning. 相似文献
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Kanagaraj Palaniyandi Qing Zhao Xiu-Bao Chang 《International Journal of Biochemistry and Molecular Biology》2011,2(2):155-167
Incubation of the drug-sensitive H69, a small cell lung cancer cell line, with increased concentrations of adriamycin yielded multidrug resistant (MDR) H69AR cells that over-express multidrug resistance-associated protein (MRP1). MRP1 co-transports its substrate with glutathione (GSH), leading to lower intracellular GSH. In this report we tested whether depleting intracellular GSH in MRP1-expressing cells could hyper-sensitize them to anticancer drugs or not. We have found that the GSH contents in MRP1-expressing cells are significantly lower than their corresponding control cells. The treatment with MRP1 substrate verapamil or the GSH synthetase inhibitor buthionine sulfoxi-mine significantly reduced the intracellular GSH contents in MRP1-expressing cells. Interestingly, depleting intracellular GSH contents can hyper-sensitize the MRP1-cDNA transfected BHK cells to daunomycin, but not the adriamycin-selected H69AR cells. Further analyses indicated that anti-apoptotic factor Bcl2 might be a factor responsible for the fact that depleting intracellular GSH could not hyper-sensitize H69AR cells to daunomycin. We hypothesized that knocking down the expression of Bcl2 could hyper-sensitize H69AR cells to daunomycin. Interestingly, infection of H69AR cells with retroviral particles harboring Bcl2 interfering RNAi not only reduced the expression of Bcl2, but also many factors that contribute to MDR, such as Bcl-xl, MRP1 and ABCC3, etc., leading to the MDR H69AR cells more sensitive to daunomycin than the parental H69 cell. Thus, although the mechanisms of the down-regulation of the genes contributing to MDR remain to be elucidated, retroviral particles harboring Bcl2 interfering RNAi could be used as an alternative way to sensitize the MDR cancer cells to anticancer drugs. 相似文献
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Jayavel Sridhar Radhakrishnan Sabarinathan Shanmugam Siva Balan Ziauddin Ahamed Rafi Paramasamy Gunasekaran Kanagaraj Sekar 《基因组蛋白质组与生物信息学报(英文版)》2011,(Z2)
In the past few decades, scientists from all over the world have taken a keen interest in novel functional units such as small regulatory RNAs, small open reading frames, pseudogenes, transposons, integrase binding attB/attP sites, repeat elements within the bacterial intergenic regions (IGRs) and in the analysis of those junk regions for ge- nomic complexity. Here we have developed a web server, named Junker, to facilitate the in-depth analysis of IGRs for examining their length distribution, four-quadrant... 相似文献
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Senthilkumar R Sabarinathan R Hameed BS Banerjee N Chidambarathanu N Karthik R Sekar K 《Bioinformation》2010,4(7):271-275
An Internet computing server has been developed to identify all the occurrences of the internal sequence repeats in a protein and DNA sequences. Further, an option is provided for the users to check the occurrence(s) of the resultant sequence repeats in the other sequence and structure (Protein Data Bank) databases. The databases deployed in the proposed computing engine are up-to-date and thus the users will get the latest information available in the respective databases. The server is freely accessible over the World Wide Web (WWW). AVAILABILITY: http://bioserver1.physics.iisc.ernet.in/fair/ 相似文献