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121.
Sedigheh Zakeri Mandana Afsharpad Faezeh Ghasemi Ahmad Raeisi Qutbuddin Kakar Hoda Atta Navid Dinparast Djadid 《Experimental parasitology》2011,(1):167-172
The main aim of the present study was to investigate the frequency of SNPs-haplotypes of dhfr and dhps genes associated to sulfadoxine–pyrimethamine (SP) resistance in Plasmodium vivax clinical isolates circulating in a malaria endemic area, Pakistan. All 164 collected isolates were analyzed for SNPs-haplotypes at positions 13, 33, 57, 58, 61, 117 and 173 of pvdhfr and 383 and 553 of pvdhps genes using PCR–RFLP methods. All examined isolates were found to carry wild-type amino acids at positions 13, 33, 57, 61 and 173, while 58R and 117N mutations were detected among 15.2% and 53.6% of isolates, respectively. Based on the size polymorphism of pvdhfr genes at repeat region, type B (79.3%) was the most prevalent variant. The combination of pvdhfr and pvdhps haplotypes demonstrated nine distinct haplotypes. The three most prevalent haplotypes were I13P33F57S58T61S117I173/A383A553 (43.9%), I13P33F57S58T61N117I173/A383A553 (33.6%) and I13P33F57R58T61N117I173/A383A553 (12.2%). The presence of mutant haplotypes is worrying and indicates the emergence of drug tolerant/resistant P. vivax isolates in Pakistan in near future. 相似文献
122.
Ilkhani H Ganjali MR Arvand M Hejazi MS Azimi F Norouzi P 《International journal of biological macromolecules》2011,49(5):1117-1123
Metal ion-DNA interactions are important in nature, often changing the genetic material's structure and function. A new Yb complex of YbCl3 (tris(8-hydroxyquinoline-5-sulfonic acid) ytterbium) was synthesized and utilized as an electrochemical indicator for the detection of DNA oligonucleotide based on its interaction with Yb(QS)3. Cyclic voltammetry (CV) and fluorescence spectroscopy were used to investigate the interaction of Yb(QS)3 with ds-DNA. It was revealed that Yb(QS)3 presented an excellent electrochemical activity on glassy carbon electrode (GCE) and could intercalate into the double helix of double-stranded DNA (ds-DNA). The binding mechanism of interaction was elucidated on glassy carbon electrode dipped in DNA solution and DNA modified carbon paste electrode by using differential pulse voltammetry and cyclic voltammetry. The binding ratio between this complex and ds-DNA was calculated to be 1:1. The extent of hybridization was evaluated on the basis of the difference between signals of Yb(QS)3 with probe DNA before and after hybridization with complementary DNA. With this approach, this DNA could be quantified over the range from 1 × 10−8 to 1.1 × 10−7 M. The interaction mode between Yb(QS)3 and DNA was found to be mainly intercalative interaction. These results were confirmed with fluorescence experiments. 相似文献
123.
124.
The reconstruction of reticulate evolutionary histories in plants is still a major methodological challenge. Sequences of the ITS nrDNA are a popular marker to analyze hybrid relationships, but variation of this multicopy spacer region is affected by concerted evolution, high intraindividual polymorphism, and shifts in mode of reproduction. The relevance of changes in secondary structure is still under dispute. We aim to shed light on the extent of polymorphism within and between sexual species and their putative natural as well as synthetic hybrid derivatives in the Ranunculus auricomus complex to test morphology-based hypotheses of hybrid origin and parentage of taxa. We employed direct sequencing of ITS nrDNA from 68 individuals representing three sexuals, their synthetic hybrids and one sympatric natural apomict, as well as cloning of ITS copies in four representative individuals, RNA secondary structure analysis, and landmark geometric morphometric analysis on leaves. Phylogenetic network analyses indicate additivity of parental ITS variants in both synthetic and natural hybrids. The triploid synthetic hybrids are genetically much closer to their maternal progenitors, probably due to ploidy dosage effects, although exhibiting a paternal-like leaf morphology. The natural hybrids are genetically and morphologically closer to the putative paternal progenitor species. Secondary structures of ITS1-5.8S-ITS2 were rather conserved in all taxa. The observed similarities in ITS polymorphisms suggest that the natural apomict R. variabilis is an ancient hybrid of the diploid sexual species R. notabilis and the sexual species R. cassubicifolius. The additivity pattern shared by R. variabilis and the synthetic hybrids supports an evolutionary and biogeographical scenario that R. variabilis originated from ancient hybridization. Concerted evolution of ITS copies in R. variabilis is incomplete, probably due to a shift to asexual reproduction. Under the condition of comprehensive inter- and intraspecific sampling, ITS polymorphisms are powerful for elucidating reticulate evolutionary histories. 相似文献
125.
Objectives: We investigated how often journal articles reporting on human HIV research in four developing world countries mention any institutional review boards (IRBs) or research ethics committees (RECs), and what factors are involved. Methods: We examined all such articles published in 2007 from India, Nigeria, Thailand and Uganda, and coded these for several ethical and other characteristics. Results: Of 221 articles meeting inclusion criteria, 32.1% did not mention IRB approval. Mention of IRB approval was associated with: biomedical (versus psychosocial) research (P = 0.001), more sponsor‐country authors (P = 0.003), sponsor‐country corresponding author (P = 0.047), mention of funding (P < 0.001), particular host‐country involved (P = 0.002), journals having sponsor‐country editors (P < 0.001), and journal stated compliance with International Committee of Medical Journal Editors (ICMJE) guidelines (P = 0.003). Logistic regression identified 3 significant factors: mention of funding, journal having sponsor‐country editors and research being biomedical. Conclusions: One‐third of articles still do not mention IRB approval. Mention varied by country, and was associated with biomedical research, and more sponsor country involvement. Recently, some journals have required mention of IRB approval, but allow authors to do so in cover letters to editors, not in the article itself. Instead, these data suggest, journals should require that articles document adherence to ethical standards. 相似文献
126.
127.
A new species of parasitic copepod of the family Lernanthropidae is described from an immigrant population of the blotchfin
dragonet Callionymus filamentosus Valenciennes (family Callionymidae) in the Eastern Mediterranean. Both sexes are described on the basis of material caught
in Egyptian waters off the Alexandria coast at Abuqir. The new species shares with Lernanthropus breviculus Kabata, 1979 the possession of a small dorsal plate on the trunk that is so narrow at its origin that it does not overlap
the bases of the fourth legs, which are therefore visible in dorsal view. These species differ in the shape of the cephalothorax
and in the extent of the dorsal plate, which is shorter in the new species, revealing the caudal rami in dorsal view. Previous
records of parasitic copepods utilising callionymids as hosts are reviewed: most belong to the families Pennellidae and Chondracanthidae. 相似文献
128.
Ahmad S Khan MB Hoda MN Bhatia K Haque R Fazili IS Jamal A Khan JS Katare DP 《Neurochemical research》2012,37(3):516-526
Natural antioxidants have shown a remarkable reduction in oxidative stress due to excess formation of reactive oxygen species
by enhancing antioxidant mechanism in the neurodegenerative disorders. Sesame seed oil (SO) is one of the most important edible
oil in India as well as in Asian countries and has potent antioxidant properties thus the present study evaluated the neuroprotective
effect of SO by using 6-Hydroxydopamine (6-OHDA)-induced Parkinson’s disease model in mice. The mice were fed an SO mix diet
for 15 days and then 6-OHDA was injected into the right striatum of mice brain. Three weeks after 6-OHDA infusion, mice were
sacrificed and the striatum was removed. The neuroprotective role of SO on the activities of antioxidant and non-antioxidant
enzymes such as glutathione reductase (GR), glutathione-S-transferase (GST), glutathione peroxidase (GPx), catalase (CAT)
and content of glutathione (GSH) and thiobarbituric acid reactive substance (TBARS) were studied in the striatum. The activities
of all the above-mentioned enzymes decreased significantly in 6-OHDA group (Lesioned) when compared with Sham. The pretreatment
of SO on antioxidant mechanism and dopamine level in the brain had shown some significant improvement in Lesion+SO (L+SO)
group when compared with Lesioned group. However, NADPH oxidase subunit, Nox2 and inflammatory stimulator Cox2 expression
was increased as well as antioxidant MnSOD level was decreased in Lesioned group while SO showed the inhibitory effect on
the activation of Nox2 and Cox2 and restored MnSOD expression in L+SO group. Increased tyrosine hydroxylase (TH) expression
in substantia nigra as well as dopamine and its metabolite DOPAC level in L+SO group also support our findings that SO may
inhibit activation of NADPH oxidase dependent inflammatory mechanism due to 6-OHDA induced neurotoxicity in mice. 相似文献
129.
MP Dore G Fanciulli PA Tomasi G Realdi G Delitala DY Graham HM Malaty 《Helicobacter》2012,17(5):369-373
Background: Helicobacter pylori infection is typically acquired in childhood, and following the acute event, it is thought that most infections remain asymptomatic. H. pylori has been suggested to protect against diarrhea in childhood. Aim: To examine the role of H. pylori in gastrointestinal symptoms in children. Materials and Methods: A cross‐sectional sero‐epidemiologic study was conducted in Porto Torres, Sardinia, Italy. Demographic information, socioeconomic factors, and the frequency of upper gastrointestinal symptoms during the previous 3 months (e.g., abdominal pain, diarrhea, nausea, heartburn, halitosis, slow digestion, belching, and weight loss) were evaluated by a questionnaire. H. pylori status was determined by ELISA. Results: Approximately 95% (N = 1741) of school children between the age of 6 and 15 years from Porto Torres participated. The sero‐prevalence of H. pylori infection was 13.3% (229/1727) and similar in boys (13%) and girls (14%) (p = .57). Nausea/vomiting (odds ratio (OR) = 2.2 (95% CI = 1.2–5.1)) and diarrhea (OR = 2.1 (95% CI = 1.3–2.8)) were each significantly associated with H. pylori infection, and these associations remained significant after controlling for other study variables. There was no significant association between H. pylori and abdominal pain or heartburn (p > .25). Conclusions: The study does not support either a role of H. pylori infection in abdominal pain in children or a protective role against diarrheal illnesses or nausea/vomiting. 相似文献
130.