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排序方式: 共有171条查询结果,搜索用时 39 毫秒
91.
Sreekumar C Hill DE Miska KB Rosenthal BM Vianna MC Venturini L Basso W Gennari SM Lindsay DS Dubey JP 《Experimental parasitology》2004,107(1-2):65-71
Canine isolates of Hammondia heydorni from Argentina, Brazil, and the United States were analysed for genetic diversity. A total of 14 isolates were tested for their ability to produce amplification using three PCR assays, one targeting the common toxoplasmatiid ITS-1 region and 2 amplifying novel, H. heydorni-specific loci, HhAP7 and HhAP10. While the ITS-1 fragments could be amplified from all isolates, only six isolates were capable of amplifying the fragments from the novel loci. The PCR products were further investigated for genetic diversity using restriction fragment length polymorphism (RFLP) and single strand conformation polymorphism (SSCP) techniques. Polymorphism in the digestion pattern was evident only at the HhAP10 locus, differentiating two of the Argentinean isolates from the remainder. Mobility shifts on SSCP gels revealed that the two Argentinean isolates were not only different from the other four isolates, but also differed from each other, both at the HhAP7 and HhAP10 loci. The ITS-1 fragments of all isolates were identical by RFLP. However, two distinct mobility patterns resulted when the products were electrophoresed on SSCP gels. Based on the sequence data from the ITS-1 and the two random loci, the isolates could be broadly classified into two distinct groups, within which minor polymorphisms were evident. In contrast, very little heterogeneity occurred in the sequences of corresponding ITS-1 regions of Neospora caninum and Toxoplasma gondii isolates. Thus, it is concluded that there is a considerable degree of microheterogeneity among isolates of H. heydorni. This diversity should be taken into consideration while attempting to elucidate the systematics, diagnostics, and biology of H. heydorni in relation to N. caninum. 相似文献
92.
Nair KS Jaleel A Asmann YW Short KR Raghavakaimal S 《American journal of physiology. Endocrinology and metabolism》2004,286(6):E863-E874
Proteomics is the comprehensive and systematic study of proteins, which are functional molecules. Although proteins are products of gene expression, there are more proteins than genes due to the posttranslational modifications of proteins, making the study of proteins difficult. Protein expression is tissue specific, and its function is modulated by variety of factors, including other proteins, phosphates, sulfates, carbohydrates, and lipids, as well as other metabolites. Because of the dynamic nature of protein expression and posttranslational modifications, identification and quantification of proteins alone are not sufficient to understand functional changes. Emerging technologies will allow investigators to perform a combination of metabolic labeling and identification as well as quantification and measurement of the synthesis rates of a large number of proteins in a tissue. This offers the opportunity to better understand the regulation of tissue functions. Rapid advances in mass spectrometry, protein purification techniques, isotope labeling of proteins, and bioinformatics are likely to improve our understanding of physiological states and altered functions in diseased states. Such mechanistic information will improve the ability to perform early diagnosis of tumors and other diseases and develop prognostic indexes and novel therapies. 相似文献
93.
Purification of the simian virus 40 (SV40) T antigen DNA-binding domain and characterization of its interactions with the SV40 origin. 总被引:3,自引:1,他引:2 下载免费PDF全文
W S Joo X Luo D Denis H Y Kim G J Rainey C Jones K R Sreekumar P A Bullock 《Journal of virology》1997,71(5):3972-3985
To better define protein-DNA interactions at a eukaryotic origin, the domain of simian virus 40 (SV40) large T antigen that specifically interacts with the SV40 origin has been purified and its binding to DNA has been characterized. Evidence is presented that the affinity of the purified T antigen DNA-binding domain for the SV40 origin is comparable to that of the full-length T antigen. Furthermore, stable binding of the T antigen DNA-binding domain to the SV40 origin requires pairs of pentanucleotide recognition sites separated by approximately one turn of a DNA double helix and positioned in a head-to-head orientation. Although two pairs of pentanucleotides are present in the SV40 origin, footprinting and band shift experiments indicate that binding is limited to dimer formation on a single pair of pentanucleotides. Finally, it is demonstrated that the T antigen DNA-binding domain interacts poorly with single-stranded DNA. 相似文献
94.
Phytophthora palmivora causes bud rot, fruit and immature nut fall in India, and causes significant coconut yield losses. Genetic variability was estimated in 70 isolates representing seven populations from the Kerala and Karnataka regions using random amplified polymorphic DNA (RAPD) markers. RAPDs generated a total of 163 markers with 15 decamer primers, of which 92% were found to be polymorphic. The number of polymorphic loci within a single population varied from 45 to 92 with estimated hetrozygosities ranging from 0.08 to 0.23. The majority of the genetic diversity was distributed within populations (68.25%) and only 31.75% were among populations. Genetic relationships estimated by the unweighted pair‐group method with arithmatic averaging (UPGMA) revealed clear separation of Kerala and Karnataka populations. 相似文献
95.
Cultures of 12 South African isolates of an undescribedFusarium species resembling but distinct fromF camptoceras were analysed for the presence of diacetoxyscirpenol (DAS), neosolaniol monoacetate (NMA), and T-2 toxin, by capillary gas chromatography utilizing electron capture detection. No DAS or T-2 toxin could be detected in any of the cultures of the isolates. NMA was, however, detected in 10 of the 12 isolates at levels ranging from 310 to 2060 ng/g. The method used, was primarily developed for the determination of DAS and T-2 toxin in fungal cultures and grain samples but was found to be suitable for the coextraction of NMA at an average recovery of 80.8%, with a detection limit in the order of 100 ng/g. Supportive evidence for the presence of the NMA was obtained by capillary gas chromatography / mass spectrometry. Regarded as a relatively rare trichothecene, NMA has never been reported to occur naturally and has previously been shown to be produced by only a fewFusarium strains. 相似文献
96.
Despite their remoteness from sources of atmospheric pollutant emissions, the Afromontane tarns in the Maloti-Drakensberg region are perfect candidates to study the negative effects of acidifying atmospheric pollution, because mountain lakes are widely recognised as sentinel ecosystems, unimpacted by direct human disturbance within their catchments. Thirty-four tarns were sampled in the Maloti-Drakensberg region and most were found to be extremely sensitive to acidic deposition, as indicated by their low acid neutralising capacity. There are very few studies of freshwater critical loads for any region within South Africa. The steady-state water chemistry model (SSWC) was adapted and used to determine critical loads, whereas exceedance was estimated relative to modelled regional deposition data, in order to understand the risk of harmful effects to aquatic ecosystems. Seventy-six percent of sampled sites across the Maloti-Drakensberg would exceed critical loads even at the lowest modelled deposition levels, but there are no current measured deposition data for the region. The sensitivity of the Maloti-Drakensberg tarns needs to be considered in future policy formulation regarding acceptable levels of acidifying atmospheric pollution from South Africa’s energy sector and indicates the need for assessing aquatic ecosystem impacts in other regions of South Africa. 相似文献
97.
98.
Seema Dharni Sanchita SreeKuttan M. Unni Sreekumar Kurungot Abdul Samad Ashok Sharma 《Journal of biomolecular structure & dynamics》2016,34(1):152-162
We have investigated in vitro antifungal efficiency of nitrogen-doped carbon nanohorn (NCNH) against Rhizoctonia solani (R. solani) plant pathogenic fungi. NCNH with size of 50–60 nm and concentrations of 10, 50, 100, and 150 μg mL?1 were used. The results showed that growth of fungi in the presence of NCNH was significantly (p > .05) inhibited at 150 μg mL?1 (85.13 ± .97) after 72 h. The results were validated through computational approaches. Molecular docking analysis of NCNH with endochitinase protein of R. solani was performed to validate the potential of antifungal activity of NCNH. Docking results showed different conformations of interaction of NCNH with endochitinase enzyme. The conformation with least binding energy ?13.54 kcal/mol was considered further. It is likely that NCNH interacts with the pathogens by mechanically wrapping, which may be one of the major toxicity actions of NCNH against R. solani. The analysis showed that NCNH might interwinds to endochitinase of R. solani leading to the deactivation of the enzyme. To best of our knowledge, this is the first report of antifungal efficacy of NCNH against R. solani and provides useful information about the application of NCNH in resisting crop disease. 相似文献
99.
100.
Adaikkalam Vellaichamy Zoltán Dezs? Lellean JeBailey Arul M. Chinnaiyan Arun Sreekumar Alexey I. Nesvizhskii Gilbert S. Omenn Andrej Bugrim 《PloS one》2010,5(6)