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831.
Dillin A Hsu AL Arantes-Oliveira N Lehrer-Graiwer J Hsin H Fraser AG Kamath RS Ahringer J Kenyon C 《Science (New York, N.Y.)》2002,298(5602):2398-2401
To explore the role of mitochondrial activity in the aging process, we have lowered the activity of the electron transport chain and adenosine 5'-triphosphate (ATP) synthase with RNA interference (RNAi) in Caenorhabditis elegans. These perturbations reduced body size and behavioral rates and extended adult life-span. Restoring messenger RNA to near-normal levels during adulthood did not elevate ATP levels and did not correct any of these phenotypes. Conversely, inhibiting respiratory-chain components during adulthood only did not reset behavioral rates and did not affect life-span. Thus, the developing animal appears to contain a regulatory system that monitors mitochondrial activity early in life and, in response, establishes rates of respiration, behavior, and aging that persist during adulthood. 相似文献
832.
Rivera MN Kim WJ Wells J Driscoll DR Brannigan BW Han M Kim JC Feinberg AP Gerald WL Vargas SO Chin L Iafrate AJ Bell DW Haber DA 《Science (New York, N.Y.)》2007,315(5812):642-645
Wilms tumor is a pediatric kidney cancer associated with inactivation of the WT1 tumor-suppressor gene in 5 to 10% of cases. Using a high-resolution screen for DNA copy-number alterations in Wilms tumor, we identified somatic deletions targeting a previously uncharacterized gene on the X chromosome. This gene, which we call WTX, is inactivated in approximately one-third of Wilms tumors (15 of 51 tumors). Tumors with mutations in WTX lack WT1 mutations, and both genes share a restricted temporal and spatial expression pattern in normal renal precursors. In contrast to biallelic inactivation of autosomal tumor-suppressor genes, WTX is inactivated by a monoallelic "single-hit" event targeting the single X chromosome in tumors from males and the active X chromosome in tumors from females. 相似文献
833.
Matthew?Rocco?Price Julie?Anita Marie?Kruse M?Eric?Galvez Annaka?M?Lorincz Mauricio?Avigdor Paul?D?HeidemanEmail author 《Journal of circadian rhythms》2005,3(1):12
Background
Responsiveness to changing photoperiods from summer to winter seasons is an important but variable physiological trait in most temperate-zone mammals. Variation may be due to disorders of melatonin secretion or excretion, or to differences in physiological responses to similar patterns of melatonin secretion and excretion. One potential cause of nonphotoresponsiveness is a failure to secrete or metabolize melatonin in a pattern that reflects photoperiod length. 相似文献834.
Debra Baer Emily Mitzel Julie Pasche Neil C. Gudmestad 《American Journal of Potato Research》2001,78(4):269-277
The speed and sensitivity of PCR-based assays allow shorter turnaround times for the detection of pathogens for which culture and serological methods are difficult or unavailable. PCR was performed with primer sets Cms50 and Cms72, designed previously by Millset al. (1997) through subtractive hybridization to detectClavibacter michiganensis subspeciessepedonicus (Cms). In bacterial suspensions, fewer than three cells/10 ul reaction were detected after PCR amplicons were hybridized with specific DIG-labeled DNA probes in an enzyme-linked oligonucleosorbent assay (ELOSA). In naturally infected tuber samples representing three cultivars of potato, the diagnostic sensitivity of PCR/ ELOSA was 96%, while the specificity exceeded 99%. PCR/ELOSA detectedCms in infected tuber samples with equal sensitivity regardless of colony morphology, potato cultivar, or primer sets. 相似文献
835.
Julie A. Flood John P. Hoover 《The Canadian veterinary journal. La revue veterinaire canadienne》2009,50(8):828-834
An 8-year-old, male, Alaskan malamute was evaluated for a 2-week history of lethargy, inappetence, and distended abdomen. The dog was diagnosed with severe hypothyroidism, exhibited facial myxedema and had myocardial dysfunction with ascites and pleural effusion. Myocardial function improved and facial myxedema and effusions resolved with levothyroxine supplementation. 相似文献
836.
The effects of sediment redox potential and stocking density on Pacific white shrimp Litopenaeus vannamei production performance and white spot syndrome virus resistance 下载免费PDF全文
Wiyoto Wiyoto Sukenda Sukenda Enang Harris Kukuh Nirmala Daniel Djokosetiyanto Julie Ekasari 《Aquaculture Research》2017,48(6):2741-2751
Redox potential represents the intensity of anaerobic condition in the pond sediment, which may affect the dominant microbial transformations of substances, the toxins production, mineral solubility, as well as the water quality in the sediment–water interface inhabited by the shrimp. This study evaluates the effect of sediment redox potential in conjunction with stocking density on shrimp production performance, immune response and resistance against white spot syndrome virus (WSSV) infection. A completely randomized two factors experimental design was applied with three different sediment redox potential, i.e. ?65, ?108 and ?06 mV, and two shrimp densities, i.e. low (60 shrimp m?2) and high (120 shrimp m?2). Shrimp juveniles with an initial mean body weight of 5.32 ± 0.22 g were maintained in semi‐outdoor fibre tanks (270 L in capacity) for 35 days of experimental periods. At the bottom of each tank, 5‐cm deep soil substrate with different redox potential was added according to the treatments. The survival and biomass production were significantly reduced at ?206 mV sediment redox potential, regardless of stocking density. Highly negative sediment redox potential (?206 mV) and higher stocking density significantly reduced total haemocyte counts and phenoloxydase activity, and shrimp resistance to WSSV infection. We recommend to maintain the redox potential of pond sediment at a level of more than ?206 mV. 相似文献
837.
838.
Johnson JM Rajic A McMullen LM 《The Canadian veterinary journal. La revue veterinaire canadienne》2005,46(2):141-146
Salmonella isolates (n = 209) obtained from food animals and foods in Alberta during 1996 through 1999 were tested for sensitivity to 17 antimicrobials. Of the 3553 antimicrobial susceptibility tests on Salmonella isolates, 11.8% were positive for resistance. These isolates were commonly resistant to tetracycline (35.4%), streptomycin (32.5%), sulfamethoxazole (28.7%), ticarcillin (27.3%), and ampicillin (26.8%). Resistance to at least 1 antimicrobial was observed in 112 isolates (53.6%). Salmonella Typhimurium, S. Typhimurium var. Copenhagen, and S. Heidelberg were the most common serovars among isolates resistant to individual antimicrobials and multiple antimicrobials. The most common profile of multiple-antimicrobial resistance was that which included resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline, and ticarcillin. The proportions of isolates that were resistant to antimicrobials were greater among bovine isolates of Salmonella than among poultry isolates, and this difference was greater among isolates from veterinary diagnostic sources than among those from monitoring sources. 相似文献
839.
E Kange'the B McDermott D Grace C Mbae E Mulinge J Monda C Nyongesa J Ambia A Njehu 《Tropical animal health and production》2012,44(Z1):11-16
This paper reports a study estimating the prevalence of cryptosporidiosis, an emerging zoonosis, in people and cattle in Dagoretti, Nairobi. A repeated cross-sectional survey was carried out among randomly selected cattle keepers in Dagoretti, their dairy cattle and their non-cattle-keeping neighbours in the dry and wet seasons of 2006. A survey was also carried out among a group of people living with human immunodeficiency virus (HIV). Faecal samples were examined for Cryptosporidium oocysts using the modified Ziehl-Neelsen method; 16?% of the samples were also examined using immunofluorescence antibody (IFA) technique. Quality control consisted of blind reviews of slides, examining split samples and confirming slide results with IFA. We found that members of dairy households had a dry season cryptosporidiosis prevalence of 4?% and wet season prevalence of 0.3?%, and non-dairy households, a prevalence of 5 and 0?%, respectively. The cattle dry season prevalence was 15?%, and the wet season prevalence, 11?%. The prevalence in people living with HIV was 5?%. The laboratory quality control system showed some inconsistency within and between different tests, indicating challenges in obtaining consistent results under difficult field and working conditions. In conclusion, this is the first reported study to simultaneously survey livestock, livestock keepers and their neighbours for cryptosporidiosis. We failed to find evidence that zoonotic cryptosporidiosis is important overall in this community. This study also draws attention to the importance of quality control and its reporting in surveys in developing countries. 相似文献
840.
The effects of cross‐linking waxy maize starch with phosphorous oxychloride (POCl3), sodium trimetaphosphate (STMP), or epichlorohydrin (EPI) on degree of swell and pasting properties were studied. As expected, increased concentration of cross‐linking agent resulted in decreased granule swelling potential, Q (mL/g). The slower acting reagents, STMP (4‐hr reaction time) and EPI (17‐hr reaction time), showed a similar relation between Q value and molar concentration of agent, which was different from the faster‐acting POCl3 (30‐min reaction time). Brabender viscoamylograph results show decreased peak viscosity with increasing amounts of cross‐link agent due to increased inhibition to swelling. Brabender viscosities (BU) continued to increase after the time interval in which an uncross‐linked sample would dissolve, which may be a sign of flocculation. The magnitude of BU for all of the treatments after 41 min, plotted versus calculated molar concentration of cross‐linking agent, showed a similar trend for all three reagents, indicating that type of reagent plays little effect on the overall pasting behavior of cross‐linked waxy maize. However, when BU was plotted versus Q, starches treated with POCl3 again separated themselves with much higher viscosities than the collectively grouped EPI‐ and STMP‐treated starches. The combination of the reduced swell and higher viscosity indicates that POCl3‐treated granules have a more rigid external surface area, with hard crust formed on the outer layers of the granule. This information shows that the mechanism of action of the individual reagents plays a major role in the physicochemical behavior of the starches. 相似文献