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排序方式: 共有285条查询结果,搜索用时 105 毫秒
1.
Chen ZY Jing D Bath KG Ieraci A Khan T Siao CJ Herrera DG Toth M Yang C McEwen BS Hempstead BL Lee FS 《Science (New York, N.Y.)》2006,314(5796):140-143
A common single-nucleotide polymorphism in the brain-derived neurotrophic factor (BDNF) gene, a methionine (Met) substitution for valine (Val) at codon 66 (Val66Met), is associated with alterations in brain anatomy and memory, but its relevance to clinical disorders is unclear. We generated a variant BDNF mouse (BDNF(Met/Met)) that reproduces the phenotypic hallmarks in humans with the variant allele. BDNF(Met) was expressed in brain at normal levels, but its secretion from neurons was defective. When placed in stressful settings, BDNF(Met/Met) mice exhibited increased anxiety-related behaviors that were not normalized by the antidepressant, fluoxetine. A variant BDNF may thus play a key role in genetic predispositions to anxiety and depressive disorders. 相似文献
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The dynamics of dangling bond (DB) diffusion was studied after deuterium desorption from the silicon (100)-2x1 surface. At elevated temperatures, paired DB sites produced after desorption unpaired as deuterium atoms hopped from adjacent dimers. Below 620 kelvin, the unpaired configuration most commonly observed corresponded to two DBs on adjacent silicon dimers. At higher temperatures, unpaired DBs executed one-dimensional walks along the dimer rows, and recombination was observed with the same partner after walks lasting many minutes. The frequency and extent of these excursions increased with temperature. Above 660 kelvin, complete dissociation was observed and was sometimes followed by recombination by means of partner exchange. The implications for low-temperature materials growth are discussed. 相似文献
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Adolfo Isla Mnica Saldarriaga‐Crdoba Derie E. Fuentes Romina Albornoz Denise Haussmann Jorge Mancilla‐Schulz Alexis Martínez Jaime Figueroa Ruben Avendao‐Herrera Alejandro Yez 《Journal of fish diseases》2019,42(5):721-737
Piscirickettsia salmonisis the causative bacterial pathogen of piscirickettsiosis, a salmonid disease that causes notable mortalities in the worldwide aquaculture industry. Published research describes the phenotypic traits, virulence factors, pathogenicity and antibiotic‐resistance potential for various P. salmonisstrains. However, evolutionary and genetic information is scarce for P. salmonis. The present study used multilocus sequence typing (MLST) to gain insight into the population structure and evolution of P. salmonis. Forty‐two Chilean P. salmonisisolates, as well as the type strain LF‐89T, were recovered from diseased Salmo salar, Oncorhynchus kisutchand Oncorhynchus mykissfrom two Chilean Regions. MLST assessed the loci sequences of dnaK, efp, fumC, glyA, murG, rpoD and trpB. Bioinformatics analyses established the genetic diversity among P. salmonis isolates (H = 0.5810). A total of 23 sequence types (ST) were identified, 53.48% of which were represented by ST1, ST5 and ST2. Population structure analysis through polymorphism patterns showed few polymorphic sites (218 nucleotides from 4,010 bp), while dN/dS ratio analysis indicated purifying selection for dnaK, epf, fumC, murG, and rpoD but neutral selection for the trpB loci. The standardized index of association indicated strong linkage disequilibrium, suggesting clonal population structure. However, recombination events were detected in a group of seven isolates. Findings included genogroups homologous to the LF‐89T and EM‐90 strains, as well as a seven‐isolate hybrid genogroup recovered from both assessed regions (three O. mykiss and four S. salar isolates). The presented MLST scheme has comparative potential, with promising applications in studying distinct P. salmonis isolates (e.g., from different hosts, farms, geographical areas) and in understanding the epidemiology of this pathogen. 相似文献
5.
Z Sánchez MA Lammoglia MA Alarcón JJ Romero CS Galina 《Reproduction in domestic animals》2015,50(4):574-579
The present assay attempts to evaluate the feasibility of using embryo transfer in small community farmers by in vivo study and by modelling the results obtained. From the total of 59 donor cows, 62.7% responded to treatment, with a significant difference (p = 0.002) in the percentage of the response between breeds, being 90.5% (19/21) in Holstein and 47.4% (18/38) in Brahman. A total of 283 embryos were graded as transferable, while 141 as non‐transferable, without difference in the percentage of transferable embryo by breed (p = 0.18). The mean of transferable embryos graded as class I and II was not different between Holstein and Brahman (p = 0.96 and p = 0.92, respectively); besides, no differences were observed in the other grades (non‐transferable). The highest difference in costs, regardless of its quality by breed, was seen in the lower levels of probable fertility of the embryo transferred, even reaching several hundred dollars. When modelling the expected costs for embryo produced and transferred, values can reach nearly $2000.00 when the probable fertility is only 10%. However, when the probable fertility was 60%, embryo cost was close to $300.00. This technology seems to be viable on average or high‐scale systems, having a superovulatory response between 60 and 80% with 4–6 transferrable embryos. Yet, in small‐scale farming, due to the reduced number of donors and/or recipients, the costs surpass the economical feasibility of the technique. 相似文献
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AE Domínguez‐Rebolledo F Martínez‐Pastor AF Bisbal JL Ros‐Santaella O García‐Álvarez A Maroto‐Morales AJ Soler JJ Garde MR Fernández‐Santos 《Reproduction in domestic animals》2011,46(3):393-403
Oxidative stress represents a challenge during sperm manipulation. We have tested the effect of increasing hydrogen peroxide (H2O2) levels on red deer spermatozoa after cryopreservation, and the role of male‐to‐male variation in that response. In a first experiment, eight thawed samples were submitted to 0, 25, 50, 100 and 200 μm H2O2 for 2 h at 37°C. Intracellular reactive oxygen species (H2DCFDA‐CM) increased with H2O2 concentration, but we only detected a decrease in sperm function (motility by CASA and chromatin damage by sperm chromatin structure assay) with 200 μm . Lipoperoxidation assessed by the thiobarbituric acid reactive substance (TBARS) method increased slightly with 50 μm H2O2 and above. In a second experiment, samples from seven males were submitted to 0 and 200 μm H2O2 for 2 h, triplicating the experiment within each male. Males differed at thawing and regarding their response to incubation and H2O2 presence. We found that the kinematic parameters reflected male‐to‐male variability, whereas the response of the different males was similar for lipid peroxidation and viability. A multiparametric analysis showed that males grouped differently if samples were assessed after thawing, after incubation without H2O2 or after incubation with H2O2. Red deer spermatozoa are relatively resilient to H2O2 after thawing, but it seems to be a great male‐to‐male variability regarding the response to oxidative stress. The acknowledgement of this individual variability might improve the development of optimized sperm work protocols. 相似文献
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笔者在临床上曾遇到一疑似“碘酊”致牛死亡的病例,由于未曾见过碘酊致牛死亡的报道,查阅资料也终未得到答案.笔者将其整理如下,供同行探讨。 相似文献
9.
Moore DA Atwill ER Kirk JH Brahmbhatt D Herrera Alonso L Hou L Singer MD Miller TD 《Journal of the American Veterinary Medical Association》2003,223(6):839-845
OBJECTIVE: To evaluate the effect of daily oral administration of decoquinate to neonatal calves experimentally challenged with various numbers of Cryptosporidium parvum oocysts. DESIGN: Clinical trial. ANIMALS: 75 calves. PROCEDURE: Calves were purchased from a commercial dairy during a 5-week period. Calves were housed in individual hutches and fed milk replacer with or without decoquinate (2 mg/kg [0.9 mg/lb per day]). Calves were randomly assigned to treatment and 1 of 5 challenge groups (0, 50, 100, 1000, or 10,000 C. parvum oocysts in 60 mL of saline [0.9% NaCl] solution administered p.o. on the day after arrival). Calves were maintained in the study for as long as 28 days. Calves were clinically assessed for diarrhea and dehydration. Fecal samples were submitted for oocyst enumeration 3 times each week. RESULTS: Treatment did not affect number of days to first watery feces (diarrhea), number of days to first oocyst shedding, or duration of diarrhea or oocyst shedding. Duration of oocyst shedding was significantly associated with challenge dose of oocysts administered to calves and number of days to first oocyst shedding. Duration of diarrhea and number of days to first oocyst shedding were significantly associated with week of arrival and number of days to first watery diarrhea. CONCLUSIONS AND CLINICAL RELEVANCE: Daily treatment with decoquinate at the dosage used in this study did not affect oocyst shedding or clinical signs associated with cryptosporidiosis. However, there was an indication that if the number of oocysts calves received could be reduced, then the duration of oocyst shedding and, hence, environmental loading of C. parvum oocysts could be reduced. 相似文献
10.
A 3-year-old, female, black and tan Dachshund was referred with visual impairment, bilateral anterior and posterior uveitis, poliosis, and generalized dermal depigmentation. Complete blood counts and biochemical parameters, including T3 and T4 , were normal. The skin biopsy showed lichenoid dermatoses with dermal infiltration of histiocytes and lymphocytes suggesting uveodermatological syndrome. Medical treatment was initiated with oral prednisone and azathioprine, and topical prednisolone and atropine. The clinical signs improved, vision was retained, and the skin began to repigment 2 months following the initiation of therapy. 相似文献