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51.
O. V. Nakonechnaya A. B. Kholina O. G. Koren V. Janeček A. Kohutka R. Gebauer Y. N. Zhuravlev 《Russian Journal of Genetics》2010,46(12):1417-1425
Genetic variation of Siberian dwarf pine Pinus pumila (Pall.) Regel was characterized in three marginal populations in southwestern, southern and eastern parts of the natural
species range (Baikal Area, Primorye, Kamchatka) using isozyme analysis. Analysis involving 16 isozyme loci encoding ten enzyme
systems was conducted. Our results confirm that P. pumila is one of the most polymorphic species in the genus Pinus. Three marginal populations exhibited high genetic variation (P
95 = 68.8%, H
o = 0.247, H
e = 0.291). Populations heterogeneity and significantly high level of divergence in coniferous (F
ST = 0.050, D
N = 0.044) reflect their genetic originality. In summary, it was shown that the level of genetic variation characteristic for
P. pumila in other parts of the not only is reproduced in the populations examined but even is close to maximum there. 相似文献
52.
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54.
Alcides AP Brazier JS Pinto LJ Balassiano IT Boente RF de Paula GR Ferreira EO Avelar KE Miranda KR Ferreira MC Domingues RM 《Antonie van Leeuwenhoek》2007,92(1):53-59
A total of 35 Brazilian isolates of Clostridium difficile from faecal stools and four isolates from hospital environments were analyzed by PCR ribotyping. A whole cell protein profile
(as an alternative for serogrouping), in vitro toxin production and susceptibility to vancomycin, metronidazole and clindamycin
were also investigated. All strains were typeable by both phenotypic and genotypic methods, and a total of 13 different PCR
ribotypes were identified, of which seven (132, 133, 134, 135, 136, 142 and 143) were considered new types and accounted for
78.5% of all samples evaluated (including hospital environments). A non-toxigenic C. difficile PCR ribotype 133 was detected in all children groups examined (inpatients, outpatients and healthy children), whilst toxigenic
PCR ribotypes 015, 131, 134 and 135 were associated mostly with symptomatic children. Serogroups G and D were disseminated
both in patients from the community and from the pediatric hospital, with group G prevalent among outpatient children. All
strains were susceptible to vancomycin and metronidazole but high levels of resistance to clindamycin were found, especially
among serogroups G and D. Co-existence of different ribotypes and serogroups in the same individual was observed. The new
seven ribotypes found in this investigation may represent strains characteristic of this region of Brazil. 相似文献
55.
Structural basis for the recruitment of ERCC1-XPF to nucleotide excision repair complexes by XPA
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Tsodikov OV Ivanov D Orelli B Staresincic L Shoshani I Oberman R Schärer OD Wagner G Ellenberger T 《The EMBO journal》2007,26(22):4768-4776
The nucleotide excision repair (NER) pathway corrects DNA damage caused by sunlight, environmental mutagens and certain antitumor agents. This multistep DNA repair reaction operates by the sequential assembly of protein factors at sites of DNA damage. The efficient recognition of DNA damage and its repair are orchestrated by specific protein-protein and protein-DNA interactions within NER complexes. We have investigated an essential protein-protein interaction of the NER pathway, the binding of the XPA protein to the ERCC1 subunit of the repair endonuclease ERCC1-XPF. The structure of ERCC1 in complex with an XPA peptide shows that only a small region of XPA interacts with ERCC1 to form a stable complex exhibiting submicromolar binding affinity. However, this XPA peptide is a potent inhibitor of NER activity in a cell-free assay, blocking the excision of a cisplatin adduct from DNA. The structure of the peptide inhibitor bound to its target site reveals a binding interface that is amenable to the development of small molecule peptidomimetics that could be used to modulate NER repair activities in vivo. 相似文献
56.
We investigated the long-term effects of divorce and early separation from one parent on HPA axis reactivity, in young adults without psychopathology. Participants were 44 young subjects, 22 whose parents divorced before they reached age 10, and 22 controls. Psychiatric symptomatology was measured with the Brief Symptom Inventory (BSI), family perceived stress by the Dyadic Adjustment Scale (DAS), and bonding by the Parental Bonding Instrument (PBI). Assessment of HPA axis function included baseline morning cortisol and ACTH and cortisol response to a CRH stimulation test. No baseline or stimulated group differences were observed for ACTH. Cortisol levels were consistently but insignificantly lower in the divorce group throughout the CRH stimulation reaching statistical significance only at 5 min (p<0.03). Group by time effect reached a trend level (p<0.06). A correlation was found between psychiatric symptomatology and PBI scores; however, both parameters did not correlate with HPA axis activity. A significant correlation was found between DAS scores and ACTH. A regression model revealed a contributing effect for both family stress and child-parent bonding to stimulated ACTH levels. These preliminary findings suggest that even in the absence of adult psychopathology, a history of childhood separation from one parent due to divorce may lead to detectable, albeit mild, long-term alterations in HPA axis activity. Furthermore, they suggest that level of stress at home and parental bonding are important determinants of this effect. It is likely that divorce has significant and sustained effects on children's HPA axis only in the context of a traumatic separation. 相似文献
57.
Tamagnan GD Brenner E Alagille D Staley JK Haile C Koren A Early M Baldwin RM Tarazi FI Baldessarini RJ Jarkas N Goodman MM Seibyl JP 《Bioorganic & medicinal chemistry letters》2007,17(2):533-537
A series of reboxetine analogs was synthesized and evaluated for in vitro binding as racemic mixtures. The best candidate (INER) was synthesized as the optically pure (S,S) enantiomer, labeled with iodine-123 and its in vivo binding determined by SPECT imaging in baboons. The in vivo specificity, selectivity, and kinetics of [123I]INER make it a promising agent for imaging NET in vivo by noninvasive SPECT imaging. 相似文献
58.
Allozyme variation of a rare relict plant, birthwort Aristolochia manshuriensis Kom., was examined. The main parameters of genetic variation in natural populations of A. manshuriensis from the Anan’evka, Nezhinka, and Malaya Borisovka river basins (Primorskii Krai) were inferred from analysis of nine enzyme systems, presumably encoded by 18 loci. At 99% polymorphism criterion, 24.4% of A. manshuriensis loci were shown to be polymorphic. The mean number of alleles per locus was 1.24; the mean observed and expected heterozygosities, 0.12 and 0.10, respectively. 相似文献
59.
Synchronization of cell death in a dinoflagellate population is mediated by an excreted thiol protease 总被引:3,自引:0,他引:3
Vardi A Eisenstadt D Murik O Berman-Frank I Zohary T Levine A Kaplan A 《Environmental microbiology》2007,9(2):360-369
Regulated programmed cell death (PCD) processes have been documented in several phytoplankton species and are hypothesized to play a role in population dynamics. However, the mechanisms leading to the coordinated collapse of phytoplankton blooms are poorly understood. We showed that the collapse of the annual bloom of Peridinium gatunense, an abundant dinoflagellate in Lake Kinneret, Israel, is initiated by CO2 limitation followed by oxidative stress that triggers a PCD-like cascade. We provide evidences that a protease excreted by senescing P. gatunense cells sensitizes younger cells to oxidative stress and may consequently trigger synchronized cell death of the population. Ageing of the P. gatunense cultures was characterized by a remarkable rise in DNA fragmentation and enhanced sensitivity to H2O2. Exposure of logarithmic phase (young) cultures to conditioning media from stationary phase (old) cells sensitized them to H2O2 and led to premature massive cell death. We detected the induction of specific extracellular protease activity, leupeptin-sensitive, in ageing cultures and in lake waters during the succession of the P. gatunense bloom. Partial purification of the conditioned media revealed that this protease activity is responsible for the higher susceptibility of young cells to oxidative stress. Inhibition of the protease activity lowered the sensitivity to oxidative stress, whereas application of papain to logarithmic phase P. gatunense cultures mimicked the effect of the spent media and enhanced cell death. We propose a novel mechanistic framework by which a population of unicellular phytoplankton orchestrates a coordinated response to stress, thereby determine the fate of its individuals. 相似文献
60.
Man-Aharonovich D Kress N Zeev EB Berman-Frank I Béjà O 《Environmental microbiology》2007,9(9):2354-2363
The eastern Mediterranean Sea is one of the most extreme oligotrophic oceanic regions on earth in terms of nutrient concentrations and primary productivity. Nitrogen fixation has been suggested to contribute to the high N : P molar ratios of approximately 28:1 found in this region. Surprisingly, no molecular biological work has been performed in situ to assess whether N(2) fixation genes actually occur in the eastern Mediterranean Sea, or to determine which organisms are responsible for this process. In this study, we examined the presence and expression of nitrogenase genes (nifH) in the upper water layer of the eastern Mediterranean. Clone libraries constructed from both DNA and reverse-transcribed PCR-amplified mRNA were examined and compared. We observed different nifH genes from diverse microbial groups, such as Cyanobacteria, Proteobacteria and methanogenic Archaea. Interestingly, numerous phylotypes were observed in coastal stations at the DNA level but none were active. However, in far offshore stations, the phylotypes observed at the DNA level were the ones that were actually active. Our preliminary study revealed diverse diazotrophs that possess and express nifH genes, which may support N(2) fixation in the eastern Mediterranean Sea. 相似文献