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Barthel R Piedrahita JA McMurray DN Payeur J Baca D Suárez Güemes F Perumaalla VS Ficht TA Templeton JW Adams LG 《American journal of veterinary research》2000,61(9):1140-1144
OBJECTIVE: To determine necropsy and Mycobacterium bovis culture results in cattle from herds with tuberculosis, the role of the bovine NRAMP1 gene in resistance and susceptibility to infection with M bovis, and the association between magnitude of the tuberculous lesions and various types of M bovis isolates. ANIMALS: 61 cattle from herds with tuberculosis in Texas and Mexico. PROCEDURE: 61 cattle were evaluated by necropsy; 59 had positive and 2 had negative caudal fold tuberculin intradermal test (CFT) results. Thirty-three cattle with positive CFT results were genotyped to evaluate polymorphism of the 3' untranslated region of the bovine NRAMP1 gene, using single-stranded conformational analysis, 9 were resistant to M bovis with no tuberculous lesions and negative M bovis culture results, and 24 were susceptible with tuberculous lesions and positive M bovis culture results. Isolates of M bovis were analyzed by restriction fragment length polymorphism (RFLP) on the basis of IS6110 sequences and direct-repeat fingerprinting patterns. RESULTS: 21 (35.6%; 21/59) cattle with positive CFT results had tuberculous lesions or positive culture results; in addition, 1 of 2 cattle with negative CFT results had tuberculous lesions and positive culture results. Tuberculous lesions were most common in the thorax (35/63; 55.5%) and lymphoid tissues of the head (10/63; 15.9%). Tuberculous lesions varied from 1 to 11/animal; 8 of 21 (38.1%) had solitary lesions. Associations were not found between resistance or susceptibility to infection with M bovis and polymorphism in the NRAMP1 gene or between the magnitude of the lesions and various RFLP types of M bovis isolates. CONCLUSIONS AND CLINICAL RELEVANCE: The NRAMP1 gene does not determine resistance and susceptibility to infection with M bovis in cattle. 相似文献
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Some recalcitrant organic wastes, which contain a large proportion of lignin or cellulose, are not changed much by composting, and thus the effectiveness of the compost as fertilizer is usua.lly low. In this study, incubation of unripe compost with ligno-cellulolytic microorganisms —Trichoderma viride orBacillus spp. — was investigated to increase the degree of humification of the organic matter present, and improve ils quality as a soil amendment. High-performance liquid chromatography (HPLC) analyses together with humification indices and electrofocusing patterns were used to monitor the evolution of the humic substances during the incubation process. Plant growth effects exerted by Azotobacter chroococcum on lettuce plants growing on the previously incubated compost were affected by the length of incubation and by changes in the composition of humic substances. Higher organic matter content and better humification seem to be important factors for predictingA. chroococcum hebaviour in the rhizosphere. 相似文献
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Sperm preparation through Sephadex™ filtration improves in vitro fertilization rate of buffalo oocytes 
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下载免费PDF全文 AU Husna A Azam S Qadeer MA Awan S Nasreen Q Shahzad A Fouladi‐Nashta M Khalid S Akhter 《Reproduction in domestic animals》2018,53(2):377-384
Routinely, swim‐up method is used to separate high‐quality sperm; however, long processing time and close cell‐to‐cell contact during the centrifugation step are inevitable elements of oxidative stress to sperm. The objective was to evaluate Sephadex? and glass wool filtration to separate motile, intact and viable sperm for in vitro fertilization in buffalo. The cumulus–oocyte complexes (COC s) were collected from ovaries of slaughtered buffaloes by aspiration and matured for 24 hr in CO 2 incubator at 38.5°C and 5% CO 2. Matured COC s were rinsed twice in fertilization TALP and placed in the pre‐warmed fertilization medium without sperm. Cryopreserved buffalo semen was thawed at 37°C for 30 s and processed through Sephadex?, glass wool filtration and swim‐up (control). Total and motile sperm recovery rates were assessed, resuspended in fertilization TALP and incubated for 15–20 min in CO 2 incubator. Samples prepared by each method were divided into two aliquots: one aliquot was studied for sperm quality (progressive motility, membrane integrity, viability, liveability), while the other was subjected to co‐incubation with sets of 10–15 in vitro matured oocytes. Data on sperm quality were analysed by ANOVA , while in vitro fertilizing rates were compared by chi‐squared test using SPSS ‐20. Least significant difference (LSD ) test was used to compare treatment means. Glass wool filtration yielded higher total and motile sperm recovery rate, while Sephadex? filtration improved (p < .05) sperm quality (progressive motility, membrane integrity, viability, liveability). Sperm preparation through Sephadex filtration yielded higher in vitro fertilization rate in terms of cleavage rate compared to glass wool filtration and swim‐up (control). In conclusion, cryopreserved Nili‐Ravi buffalo sperm selected through Sephadex filtration showed improved quality and yielded better fertilization rates (cleavage rate) of in vitro matured/fertilized oocytes. Sephadex filtration could be a promising technique for use in in vitro fertilization in buffalo. 相似文献
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Vural G Baca AU Gauci CG Bagci O Gicik Y Lightowlers MW 《Veterinary parasitology》2008,154(3-4):347-350
Investigations into the genetic strains of Echinococcus granulosus parasites occurring in sheep and cattle in Turkey were undertaken. A total of 112 hydatid cysts were investigated from sheep (100 isolates) derived from widely distributed sites within Turkey as well as from cattle (12 isolates) from the Turkish province of Kars. The parasite genotypes in these isolates were determined by DNA sequencing of part of the mitochondrial Cytochrome C oxidase 1 (cox1) gene. Haplotypes were identified which corresponded clearly to the previously described strain G1 in a total of 107 isolates, including 98 isolates from sheep and 9 isolates from cattle. Five isolates, including 2 sheep and 3 cattle, were determined to belong to the G3 genotype. Parasites of the G3 genotype were identified only in isolates derived from animals in the eastern regions of Turkey. While the majority of the isolates described here had haplotypes corresponding to the G1 genotype, none matched exactly the G1 sequence that was defined in previous studies. Analysis of all GenBank entries for E. granulosus cox1 sequences representing G1, G2 and G3 genotypes identified substantial microsequence variability. G1 and G3 could be distinguished as separate strains, however, the existence of G2 as a separate strain could not be supported. Rather, this can be regarded as a microsequence variation of G3. 相似文献
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简要总结了蘑菇圈的概念、形状和大小及有文献报道的蘑菇圈产生菌,分析了蘑菇圈生长特性和形成机理,论述了蘑菇圈对圈上植物和圈中土壤生态系统的影响,提出应加强蘑菇圈产生菌繁殖和进化机制及营养方式的研究。 相似文献
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丘陵红壤橘园不同地面管理措施的经济生态效益研究 总被引：2，自引：0，他引：2
A three-year experiment was conducted to investigate and compare the economic and ecological benefits of six types of vegetation management measures in citrus orchards of the hilly red soil region of the eastern part of China. Six vegetation treatments, including tillage without herbicide （clean tillage） and no tillage without herbicide （sod culture） and with herbicide paraquat （paraquat）, glyphosate （glyphosate）, glyphosate-glyphosate-paraquat （G-G-P）, and paraquatparaquat-glyphosate （P-P-G）, were applied in the citrus orchards on a clayey red soil with slopes of 8° and 13°and a sandy soil with slope of 25°. The results showed that the sod culture, paraquat, glyphosate, G-G-P, and P-P-G treatments reduced surface runoff by 38.8%, 42.5%, 18.7%, 28.7%, and 37.5%, then the soil-water losses by 55.5%, 51.7%, 39.9%, 46.8%, and 50.0%, and the N, P, and K nutrient losses by 60.3%, 50.2%, 37.0%, 41.8%, and 45.4%, respectively, as compared with the clean tillage treatment. The weed regeneration ratios with the treatments of clean tillage without herbicide, paraquat, glyphosate, G-G-P, and P-P-G were reduced by 55.1%, 67.2%, 30.3%, 36.8%, and 51.2%, respectively, as compared with the sod culture. The sod culture, paraquat, glyphosate, G-G-P, and P-P-G treatments could increase the soil fertility （annual accumulation of N, P, K, and OM） by 7.1%, 6.9%, 5.3%, 6.2%, and 6.6%, respectively, whereas the clean tillage treatment without herbicide reduced soil fertility by 4.4% after the three-year experiment. The citrus fruit yields in the treatments of paraquat, glyphosate, G-G-P, and P-P-G increased by 7%-10%; the soluble solid, total sugar, total acidity, sugar-acid ratio, and single fruit weight of citrus fruits of all treatments except sod culture significantly （P 〉 0.05） exceeded that of the clean tillage treatment. In general, the paraquat treatment showed the best economic and ecological benefits among the six treatments; therefore, it could be regarded as the best available vegetation 相似文献
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Baca HK Ashley C Carnes E Lopez D Flemming J Dunphy D Singh S Chen Z Liu N Fan H López GP Brozik SM Werner-Washburne M Brinker CJ 《Science (New York, N.Y.)》2006,313(5785):337-341
Amphiphilic phospholipids were used to direct the formation of biocompatible, uniform silica nanostructures in the presence of Saccharomyces cerevisiae and bacterial cell lines. The cell surfaces organize multilayered phospholipid vesicles that interface coherently with the silica host and help relieve drying stresses that develop with conventional templates. These host structures maintain cell accessibility, addressability, and viability in the absence of buffer or an external fluidic architecture. The cell surfaces are accessible and can be used to localize added proteins, plasmids, and nanocrystals. Prolonged cell viability combined with reporter protein expression enabled stand-alone cell-based sensing. 相似文献
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A'Hearn MF Belton MJ Delamere WA Kissel J Klaasen KP McFadden LA Meech KJ Melosh HJ Schultz PH Sunshine JM Thomas PC Veverka J Yeomans DK Baca MW Busko I Crockett CJ Collins SM Desnoyer M Eberhardy CA Ernst CM Farnham TL Feaga L Groussin O Hampton D Ipatov SI Li JY Lindler D Lisse CM Mastrodemos N Owen WM Richardson JE Wellnitz DD White RL 《Science (New York, N.Y.)》2005,310(5746):258-264
Deep Impact collided with comet Tempel 1, excavating a crater controlled by gravity. The comet's outer layer is composed of 1- to 100-micrometer fine particles with negligible strength (<65 pascals). Local gravitational field and average nucleus density (600 kilograms per cubic meter) are estimated from ejecta fallback. Initial ejecta were hot (>1000 kelvins). A large increase in organic material occurred during and after the event, with smaller changes in carbon dioxide relative to water. On approach, the spacecraft observed frequent natural outbursts, a mean radius of 3.0 +/- 0.1 kilometers, smooth and rough terrain, scarps, and impact craters. A thermal map indicates a surface in equilibrium with sunlight. 相似文献
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In vitro production of porcine zygotes using intracytoplasmic injection of vitrified sperm 下载免费PDF全文
下载免费PDF全文 CC Arraztoa C Baca Castex GM Alvarez PD Cetica DM Neild 《Reproduction in domestic animals》2017,52(5):775-780
The objectives of this study were to evaluate if vitrified porcine spermatozoa are able to maintain their capacity to produce zygotes in vitro using intracytoplasmic sperm injection (ICSI) and to evaluate the zygote development in two in vitro atmospheric conditions: 5% CO2 and tri‐gas. A group of porcine oocytes maturated in vitro were injected with vitrified‐warmed sperm (treatment group) and another group, with sperm diluted and conserved at 17°C (control group). To evidence parthenogenetic activation, some oocytes were submitted to a Sham test. The injected oocytes were cultured in G1 medium at 38°C, 100% humidity and 5% CO2 or tri‐gas. No significant differences (p > .05) were observed in embryo development between the oocytes injected with vitrified‐warmed sperm (31.8%; 36/113), and those injected with semen diluted and conserved at 17°C (35.5%; 32/90), when cultured in 5% CO2 or under tri‐gas atmosphere (42.9%; 39/91 vs. 34.2%; 26/76, respectively). No significant differences (p > .05) were observed in the percentage of pronuclei (PN) obtained between 5% CO2 and tri‐gas, within each treatment either. Of the 52 oocytes submitted to the Sham test, only two presented a female PN (activation) indicating that the PN observed in the treatment group were a product of fertilization and not parthenogenetic activation. To conclude, porcine sperm vitrified using spheres, at a concentration of 5 × 106 spermatozoa/ml in TALP medium with 1% bovine serum albumin (BSA), conserve condensed and intact chromatin capable of producing early embryo development up to the pronuclear stage. 相似文献