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991.
992.
People dwelling in different cities of the Potohar region, Pakistan, are mostly dependent on surface water for drinking and domestic use. In an attempt to make available potable, safe water, filtration plants were constructed along with dams in the Potohar region. Water samples from these filtration plants were collected and analyzed for total and faecal coliform bacteria as well as for total viable count. Results showed that bacterial indicators of faecal contamination were numerous and significantly greater than World Health Organization recommended guidelines. Accordingly, antibacterial activity of methanolic and aqueous extracts of different parts of Solanum surrattense were assessed in vitro against waterborne pathogens. Fruits exhibited more antibacterial activities at incubation at 37°C than shoots and roots, which showed lowest Minimum Inhibitory Concentration (MIC) and zones of inhibition. These results suggest that plants offer a great potential for purification of drinking water that needs to be explored further because fruit extract of the aforementioned plant can be of practical use against waterborne pathogens. 相似文献
993.
Iceland is situated in an important subarctic transition area where complex oceanographic dynamics occur. The intertidal, subtidal, and deep-sea faunal communities of Iceland are being intensively studied, as a critical resource for continued sustainability of fisheries and the preservation of northern littoral ecosystems. However, the meiofaunal communities and the environmental factors affecting them are still relatively poorly known. The meiobenthic metazoan community was studied with core sampling in 23 sandy beaches along the intertidal zone of the Iceland coast in a campaign developed in September 2003. Small-scale variation in meiofauna composition (major taxa) was explored and related to biotic and abiotic factors at different scales, such as beach exposure, granulometry, and organic matter content. Differences in meiofaunal community structure at a low taxonomic resolution appeared among beaches located within wide biogeographical zones of hydrobiological significance (NE and SW Shelf regions) and exposure degrees. Seventeen major taxa were recorded. In contrast with more local and taxon-focused studies, oligochaetes were the dominant group all around Iceland, followed by nematodes, turbellarians, gastrotrichs, and copepods (mainly harpacticoids). Acari, ascidians, bivalves, cnidarians, collembolans, gastropods, isopods, kinorhynchs, insects, nemerteans, ostracods, and polychaetes were relatively scarce groups, together being less than 1.6% of the meiofauna. There was a large variation in meiofaunal abundance between sites. Maximum abundances (>500 ind. cm?2) were found in Sau?arkrökur, Hraunhafnartangi, and Skálaness, whereas minimum abundances (<40 ind. cm?2) were recorded in Magnavík, Jokülsárlón (glacier beach site), Vikurnúpur, Breidalsvík, and Stokknes. We did not find a clear pattern in overall meiofaunal abundance regarding the degree of exposure of beaches. Oligochaetes, nematodes, and copepods were relatively more abundant in sheltered beaches, whereas turbellarians and gastrotrichs tended to be more abundant in exposed beaches. The best correlates of meiofaunal composition and abundance within beaches were the proportion of gravels and the content of utilizable organic matter in the sediment. We should consider factors operating at wider scales (importantly beach exposure and overall situation in the complex oceanographical context of Iceland) to find a pattern in the local structure of intertidal meiofaunal assemblages. 相似文献
994.
995.
996.
Analysis of the mitochondrial DNA control region resolved two stocks of whitemouth croaker Micropogonias furnieri in Uruguayan waters, one in the Río de la Plata and the other on the Uruguayan shelf. The whitemouth croaker is the most important coastal fishery resource along the coast and has the greatest commercial importance in the Río de la Plata and its oceanic front. The number of pair-wise differences (π) and haplotype diversity ( h ) showed significant differences between the two regions. Frequencies of mtDNA haplotypes did not differ between Río de la Plata from Bahia Blanca M. furnieri . Samples from the oceanic front showed greater genetic variability and a larger effective number of females that were an order of magnitude larger than that in Río de la Plata. Mismatch distributions showed evidence of a recent population expansion in the oceanic region, beginning c. 40 000 b.p. The presence of two stocks of the M. furnieri in the study area should be considered in the management of this species' fishery. 相似文献
997.
998.
Clinton E. Leysath Arthur F. Monzingo Jennifer A. Maynard George Georgiou Brent L. Iverson Jon D. Robertus 《Journal of molecular biology》2009,387(3):680-20900
The virulence of Bacillus anthracis is critically dependent on the cytotoxic components of the anthrax toxin, lethal factor (LF) and edema factor (EF). LF and EF gain entry into host cells through interactions with the protective antigen (PA), which binds to host cellular receptors such as CMG2. Antibodies that neutralize PA have been shown to confer protection in animal models and are undergoing intense clinical development. A murine monoclonal antibody, 14B7, has been reported to interact with domain 4 of PA (PAD4) and block its binding to CMG2. More recently, the 14B7 antibody was used as the platform for the selection of very high affinity, single-chain antibodies that have tremendous potential as a combination anthrax prophylactic and treatment. Here, we report the high-resolution X-ray structures of three high-affinity, single-chain antibodies in the 14B7 family; 14B7 and two high-affinity variants 1H and M18. In addition, we present the first neutralizing antibody-PA structure, M18 in complex with PAD4 at 3.8 Å resolution. These structures provide insights into the mechanism of neutralization, and the effect of various mutations on antibody affinity, and enable a comparison between the binding of the M18 antibody and CMG2 with PAD4. 相似文献
999.
1000.
Elvira R. Eivazova Aleksey Gavrilov Iryna Pirozhkova Olga V. Iarovaia Marc Lipinski 《Journal of molecular biology》2009,386(4):929-4410
In interphase nuclei as in metaphase chromosomes, the genome is organized into topologically closed loop domains. Here, we have mapped the ends of the loop domain that contains the Ifng (interferon-γ) gene in primary and cultured murine T-lymphocytes. To determine whether the ends of the loop are located in close proximity to each other in the nuclear space, the 3C (chromosome conformation capture) technique, which detects protein-mediated DNA-DNA interactions, was utilized. A strong interaction was demonstrated between the two ends of the loop, which were close enough to become cross-linked in vivo in the presence of paraformaldehyde. Chromatin immunoprecipitation combined with the 3C technique demonstrated that topoisomerase IIα and MeCP2, but not topoisomerase IIβ, heterochromatin-associated protein HP1 or CTCF, were involved in this interaction. The present findings have important implications in terms of mechanisms of illegitimate recombination that can result in chromosomal translocations and deletions. 相似文献