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91.
Bulusu Jagannadh Kondalu R. Dharshna Priya Laveti Chandini Devi Gopiparthi Kranthi Sri 《Journal of molecular modeling》2010,16(2):285-290
The result of an exhaustive search of low-energy conformers of 1,4,7,10,13-Pentaoxacyclopentadecane is presented. The search
method combines the generation of large number of trial conformers using local nonstochastic deformations known as the Conflex
method, which is coupled to AMBER force field as the minimizer. The extent of the conformational space sampled was evaluated
from the view point of the number of duplicates of each conformer, generation of inclusion type structures without considering
the substrate and the spread of the allowed torsion angles visited during the search. It is shown that the conformational
search is exhaustive and efficient as conformers, which the metal coordinated crown ether complexes adopt, were generated.
Free energies using the AMBER structures were calculated using the model of Cramer and Truhlar. The study suggests that 1,4,7,10,13-Pentaoxacyclopentadecane
exists as a mixture of conformers in solution. The results show the efficiency of the method and could be the method of choice
in the design of synthetic macrocyclic receptors. 相似文献
92.
Anjana Jajoo Sonal Mathur Pooja Mehta Miho Yoshoika Suleyman I. Allakhverdiev Yasusi Yamamoto 《Journal of bioenergetics and biomembranes》2010,42(1):47-53
Chloride is an indispensable factor for the functioning of oxygen evolving complex (OEC) and has protective and activating
effects on photosystem II. In this study we have investigated mainly by EPR, the properties of chloride-sufficient, chloride-deficient
and chloride-depleted thylakoid membranes and photosystem II enriched membranes from spinach. The results on the effects of
different chloride depletion methods on the structural and functional aspects of photosystem II showed that chloride-depletion
by treating PS II membranes with high pH is a relatively harsh way causing a significant and irreparable damage to the PS
II donor side. Damage to the acceptor side of PS II was recovered almost fully in chloride-deficient as well as chloride-depleted
PS II membranes. 相似文献
93.
Manoj K. Mishra Santosini Devi Alex McCormac Nigel Scott DongFang Chen Malcolm Elliott Adrian Slater 《Biologia》2010,65(4):639-646
The green fluorescent protein (GFP) was used as a visual selectable marker to produce transgenic coffee (Coffea canephora) plants following Agrobacterium-mediated transformation. The binary vector pBECKS 2000.7 containing synthetic gene for GFP (sgfp) S65T and the hygromycin phosphotransferase gene hph both controlled by 35S cauliflower mosaic virus CaMV35S promoters was used for transformation. Embryogenic cultures were initiated from hypocotyls and cotyledon leaves of in vitro grown seedlings and used as target material. Selection of transformed tissue was carried out using GFP visual selection as
the sole screen or in combination with a low level of antibiotics (hygromycin 10 mg/L), and the efficiency was compared with
antibiotics selection alone (hygromycin 30 mg/L). GFP selection reduced the time for transformed somatic embryos formation
from 18 weeks on a hygromycin (30 mg/L) antibiotics containing medium to 8 weeks. Moreover, visual selection of GFP combined
with low level of antibiotics selection improved the transformation efficiency and increased the number of transformed coffee
plants compared to selection in the presence of antibiotics. Molecular analysis confirmed the presence of the sgfp-S65T coding region in the regenerated plants. Visual screening of transformed cells using GFP by Agrobacterium-mediated transformation techniques was found to be efficient and therefore has the potential for development of selectable
marker-free transgenic coffee plants. 相似文献
94.
Jim M Dunwell Mike J Wilkinson Stephen Nelson Sri Wening Andrew C Sitorus Devi Mienanti Yuzer Alfiko Adam E Croxford Caroline S Ford Brian P Forster Peter DS Caligari 《BMC plant biology》2010,10(1):1-25
Background
Studies on host-pathogen interactions in a range of pathosystems have revealed an array of mechanisms by which plants reduce the efficiency of pathogenesis. While R-gene mediated resistance confers highly effective defense responses against pathogen invasion, quantitative resistance is associated with intermediate levels of resistance that reduces disease progress. To test the hypothesis that specific loci affect distinct stages of fungal pathogenesis, a set of maize introgression lines was used for mapping and characterization of quantitative trait loci (QTL) conditioning resistance to Setosphaeria turcica, the causal agent of northern leaf blight (NLB). To better understand the nature of quantitative resistance, the identified QTL were further tested for three secondary hypotheses: (1) that disease QTL differ by host developmental stage; (2) that their performance changes across environments; and (3) that they condition broad-spectrum resistance.Results
Among a set of 82 introgression lines, seven lines were confirmed as more resistant or susceptible than B73. Two NLB QTL were validated in BC4F2 segregating populations and advanced introgression lines. These loci, designated qNLB1.02 and qNLB1.06, were investigated in detail by comparing the introgression lines with B73 for a series of macroscopic and microscopic disease components targeting different stages of NLB development. Repeated greenhouse and field trials revealed that qNLB1.06 Tx303 (the Tx303 allele at bin 1.06) reduces the efficiency of fungal penetration, while qNLB1.02 B73 (the B73 allele at bin 1.02) enhances the accumulation of callose and phenolics surrounding infection sites, reduces hyphal growth into the vascular bundle and impairs the subsequent necrotrophic colonization in the leaves. The QTL were equally effective in both juvenile and adult plants; qNLB1.06 Tx303 showed greater effectiveness in the field than in the greenhouse. In addition to NLB resistance, qNLB1.02 B73 was associated with resistance to Stewart's wilt and common rust, while qNLB1.06 Tx303 conferred resistance to Stewart's wilt. The non-specific resistance may be attributed to pleiotropy or linkage.Conclusions
Our research has led to successful identification of two reliably-expressed QTL that can potentially be utilized to protect maize from S. turcica in different environments. This approach to identifying and dissecting quantitative resistance in plants will facilitate the application of quantitative resistance in crop protection. 相似文献95.
Anjana Sharma Sachin Kumar Chandraker Manisha Bharti 《Indian journal of microbiology》2007,47(3):233-240
Sixteen isolates of Nontubercular Mycobacteria species were isolated from drinking water supply of some educational institutes
in Jabalpur during July 2006 and were identified by biochemical test, thin layer chromatography (TLC) and high performance
liquid chromatography (HPLC) analysis and PRA ( PCR restriction enzyme analysis) of rpoB gene. Out of 21 water samples total
16 isolates of nontuberculous mycobacteria were identified, as M. terrae (6), M. szulgai (4), M. gordonae (3), and one each as M. malmoense, M. kansasii, and M. gastri. 相似文献
96.
97.
98.
In spite of the rapid advances in the development of the new proteomic technologies, there are, to date, relatively fewer studies aiming to explore the neuronal proteome. One of the reasons is the complexity of the brain, which presents high cellular heterogeneity and a unique subcellular compartmentalization. Therefore, tissue fractionation of the brain to enrich proteins of interest will reduce the complexity of the proteomics approach leading to the production of manageable and meaningful results. In this review, general considerations and strategies of proteomics, the advantages and challenges to exploring the neuronal proteome are described and summarized. In addition, this article presents an overview of recent advances of proteomic technologies and shows that proteomics can serve as a valuable tool to globally explore the changes in brain proteome during various disease states. Understanding the molecular basis of brain function will be extremely useful in identifying novel targets for the treatment of brain diseases. 相似文献
99.
Cajanus cajan rhizobial isolates were found to be unable to utilize iron bound to ferrichrome, desferrioxamine B or rhodotorulic acid,
all being hydroxamate type siderophores. A broad host range expression vector containing the Escherichia
coli
fhuA gene, encoding the outer membrane receptor for Fe-ferrichrome, was constructed. The plasmid construct (pGR1), designed to
express fhuA under the lac promoter of E. coli, complemented E. coli MB97 ΔfhuA mutant for ferri-ferrichrome utilization and also allowed Rhizobium spp. ST1 and Rhizobium spp. IC3123 to grow using iron bound to ferrichrome. Sensitivity to the antibiotic albomycin, transported via the FhuA receptor,
was found in case of MB97 as well as rhizobial transformants harboring pGR1. The rhizobial transformants expressing fhuA showed growth stimulation when co-inoculated with Ustilago maydis, a fungal species known to produce ferrichrome under iron starved conditions. Growth stimulation was also observed in the
presence of externally supplied ferrichrome. The significance of these findings in terms of the potential for improving the
survivability of rhizobial bioinoculant strains in natural soils is discussed. 相似文献
100.
Nucleic acid double helices are stabilized by hydrogen bonding and stacking forces (a combination of hydrophobic, dispersive and electrostatic forces) of the base pairs in the helix. One would predict the hydrogen bonding contributions to increase and the stacking contributions to decrease as the water activity in the medium decreases. Study of nucleobase paired duplexes in the absence of water and ultimately in pure aprotic, non-polar organic solvents is not possible with natural phosphodiester nucleic acids due to the ionic phosphate groups and the associated cations, but could be possible with non-ionic nucleic acid analogues or mimics such as peptide nucleic acids. We now report that peptide nucleic acid (PNA) (in contrast to DNA) duplexes show almost unaffected stability in up to 70% dimethylformamide (DMF) or dioxane, and extrapolation of the data to conditions of 100% organic solvents indicates only minor (or no) destabilization of the PNA duplexes. Our data indicate that stacking forces contribute little if at all to the duplex stability under these conditions. The differences in behaviour between the PNA and the DNA duplexes are attributed to the differences in hydration and counter ion release rather than to the differences in nucleobase interaction. These results support the possibility of having stable nucleobase paired double helices in organic solvents. 相似文献