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341.
Soluble nymphal antigens (HNAg) were purified by immunoaffinity chromatography using CNBr-activated Sepharose 4B coupled with immunoglobulin ligands from animals immunized with HNAg and 69–71% protected against challenge infestations, and 8% recovery of the purified protein (Aff-HNAg) was obtained. Following immunization of crossbred calves (Bos indicus×Bos taurus) with 1600 g of Aff-HNAg in three divided doses, significant rejections of larvae (p<0.001, 84.2%), nymphs (p<0.05, 61.4%) and adults (p<0.05, 58.7%) were recorded. No significant changes were recorded in the engorgement weights of the larvae and nymphs, but there was a significant (p<0.05) reduction in the weight of the engorged adults. Immunization conferred a significant decrease in the numbers of resultant nymphs (p<0.001) and adults (p<0.001) that had fed on the immunized animals. SDS-PAGE analysis identified a 39 kDa protein, previously isolated from larvae of Hyalomma anatolicum anatolicum, as the antigen responsible for the induction of resistance against all the stages of the tick.  相似文献   
342.
A study was conducted to determine the optimum dosage of the exogenous cholesterol-loaded cyclodextrins (CLC) to get maximum cryoprotection for bubaline spermatozoa. In the present study, 120 × 106 spermatozoa were incubated in 2, 3 and 4 mg of CLC as grouped as Gr II, III and IV, respectively, and sperm progressive motility, intracellular Ca2+, capacitation status by protein tyrosine phosphorylation (PTP) assay and zona binding per cent (ZBP) and cleavage rate (CR) of the cryopreserved buffalo spermatozoa by in vitro fertility assay were assessed in comparison with an untreated control group (Gr I). Results revealed that there was a significant (p < .05) linear decrease in percentage of sperm population with higher intracellular Ca2+ and percentage of sperm population with medium or high capacitated by PTP in CLC treated from 2 to 3 mg and then increased to 4 mg/120 × 106 spermatozoa whereas sperm progressive motility, percentage of sperm population with low capacitated, ZBP and CR were increased significantly (p < .05) in sperm population treated from 2 to 3 mg CLC and then decreased to 4 mg/120 × 106 spermatozoa. The study has clearly indicated that CLC at 3 mg/120 × 106 spermatozoa has maximum beneficial effects in protection of sperm progressive motility, membrane fluidity (low intracellular Ca2+); prevention of cryocapacitation (low capacitation pattern in immunolocalization) and enhancement of in vitro ZBP and CR. Post-thaw motility of the CLC-treated sperm has shown positively significant (p < .05) correlation with sperm population with low intracellular Ca2+, low capacitated sperm population, ZBP and CR, whereas it was negatively (p < .05) correlated with sperm population with high intracellular Ca2+, medium or high capacitated sperm. The present study has revealed for the first time that incubation of spermatozoa with CLC of higher dose (>3 mg/120 × 106 spermatozoa) had adverse effects on sperm cryopreservation, although incubation of sperm with 3 mg/120 million prior to processing had minimised the freezing–thawing-associated damages in bubaline species.  相似文献   
343.
A visible atmospheric optical depth of 0.9 was measured by the Spirit rover at Gusev crater and by the Opportunity rover at Meridiani Planum. Optical depth decreased by about 0.6 to 0.7% per sol through both 90-sol primary missions. The vertical distribution of atmospheric dust at Gusev crater was consistent with uniform mixing, with a measured scale height of 11.56 +/- 0.62 kilometers. The dust's cross section weighted mean radius was 1.47 +/- 0.21 micrometers (mm) at Gusev and 1.52 +/- 0.18 mm at Meridiani. Comparison of visible optical depths with 9-mm optical depths shows a visible-to-infrared optical depth ratio of 2.0 +/- 0.2 for comparison with previous monitoring of infrared optical depths.  相似文献   
344.
Ghosh S  Sood AK  Kumar N 《Science (New York, N.Y.)》2003,299(5609):1042-1044
We report that the flow of a liquid on single-walled carbon nanotube bundles induces a voltage in the sample along the direction of the flow. The voltage that was produced fit a logarithmic velocity dependence over nearly six decades of velocity. The magnitude of the voltage depended sensitively on the ionic conductivity and on the polar nature of the liquid. Our measurements suggest that the dominant mechanism responsible for this highly nonlinear response involves a direct forcing of the free charge carriers in the nanotubes by the fluctuating Coulombic field of the liquid flowing past the nanotubes. We propose an explanation based on pulsating asymmetric ratchets. Our work highlights the device potential for nanotubes as sensitive flow sensors and for energy conversion.  相似文献   
345.
In this article, an attempt has been made to explain the failure mechanism of spun yarns. The mechanism includes the aspects of generation and distribution of forces on a fibre under the tensile loading of a yarn, the free body diagram of forces, the conditions for gripping and slipping of a fibre, and the initiation, propagation, and ultimate yarn rupture in its weakest link. A simple mathematical model for the tenacity of spun yarns has been proposed. The model is based on the translation of fibre bundle tenacity into the yarn tenacity.  相似文献   
346.
ABSTRACT:   Ecological investigations were carried out on Indian marine puffers, Chelonodon patoca, Sphaeroides oblongus, Lagocephalus lunaris and Lagocephalus inermis , the four major species available in the coastal waters of the Bay of Bengal, India. The seasonal intraspecific and interspecific abundance and average daily landings were noted. The high hepatosomatic index and low lipid ratio of muscle to liver indicated accumulation of lipid in the liver. The lipid content was at its maximum during the monsoon (July–October) in all the species as was observed from the study of the seasonal variation of liver lipids. The puffers are mainly bottom feeders and the molluscs Umbonium vesterium and Donax incarnatus are the major prey group, constituting 56.0–87.5% of their food content. The liver and ovary had the maximum toxicity in monsoon during their spawning season. The liver oils so far tested from these fishes had no toxicity and the study reveals that the ecologic information will be helpful in monitoring the quality for the safe isolation of polyunsaturated fatty acid – enriched oil from these non-conventional sources.  相似文献   
347.
Enzyme producing bacterial flora isolated from fish digestive tracts   总被引:4,自引:2,他引:4  
Isolationand enumeration of aerobic bacterial flora in the gastrointestinal tract of nineculturable freshwater teleosts, namely catla, rohu, mrigal, silver carp, grasscarp, common carp, tilapia, walking catfish and murrel have been carried out.Amylolytic, cellulolytic, lipolytic and proteolytic microflora were identifiedfrom the culture plate using selective media. The isolates were qualitativelyscreened on the basis of their extracellular enzyme producing ability. Theselected strains were further quantitatively assayed for amylase, cellulase,lipase and protease activities. Protease activity was exhibited by almost allthe bacterial isolates, while strains isolated from tilapia, grass carp andcommon carp showed considerable amylolytic and cellulolytic activities. Maximumactivity of lipase was exhibited by a strain isolated from silver carp. Thestudy indicates that there is a distinct microbial source of the digestiveenzymes – amylase, cellulase, lipase and protease, apart from endogenoussources in fish gut. The information generated from the present investigationmight contribute towards better feed formulations for carp at low cost,incorporating the enzyme producing bacterial isolates as probiotics.  相似文献   
348.
The mulberry leaves have been considered as a sole food source for silkworm, Bombyx mori (L.). In present work an attempt was made to investigate the role of low molecular weight peptide(s) isolated from mulberry leaves on silkworm rearing. Also we have tried to find out the role of free-radical scavenging activities of isolated peptide(s) on silkworm growth. Larval growth rate was found effective under the influence of peptide(s). Consumption rate of larvae after peptide(s) treatment on mulberry leaves was significantly enhanced over control. High antioxidant activity was found in Low molecular weight peptide(s) which have an effect on silkworm.  相似文献   
349.
不同种植密度和施肥水平对大豆籽粒品质的影响   总被引:12,自引:0,他引:12  
本试验自2002年开始至2004年止,从种植密度和施肥水平两方面对大豆脂肪、蛋白质含量的影响进行了分析。结果表明:种植密度对大豆籽粒的脂肪、蛋白质含量具有显著的影响,相关性分析结果显示,种植密度与大豆籽粒的脂肪含量存在着负相关性,与籽粒中的蛋白质含量之间为正相关。中国品种的脂肪含量受种植密度的影响大于美国品种,而中国品种的蛋白质含量受种植密度的影响小于美国品种。蛋脂总含量受种植密度的影响较小,并且不存在品种间的差异性。磷酸二铵的施用量与大豆籽粒脂肪含量和蛋白质含量之间没有显著的相关性,但是中美品种的品质对磷酸二铵施用量的反应不同。磷酸二铵的施用量与中国品种的脂肪含量、蛋白质含量和蛋脂总含量呈正相关,而与美国品种的脂肪、蛋白质含量和蛋脂总含量呈负相关,但相关程度均不显著。  相似文献   
350.
The variation in the kidding size of Black Bengal and Sirohi breed of goats makes them an interesting genetic material to study the underlying genetic mechanism of prolificacy. Accordingly, we studied the comparative ovarian morphometry including disparity in numbers of antral follicles of different sizes between these two breeds. Further, we evaluated the differential expression of the important candidate genes (viz., BMP15, GDF9 and BMPR1B) known to influence the ovulation rates and the prolificacy. The ovaries of Black Bengal (n = 20) goat were lighter (p < 0.01) in weight and smaller (p < 0.01) in diameter than those of Sirohi (n = 19) goats but possessed more numbers (p < 0.05) of corpus luteum (CL), large and small antral follicles. Quantitative real‐time PCR (RT‐qPCR) analysis revealed differential expression of mRNAs encoding for the BMP15 and GDF9. Small antral follicles of Black Bengal goats expressed 2.78‐fold more (p < 0.05) of BMP 15 than those of Sirohi goat. Expression of BMP15 (p < 0.01) and GDF9 (p < 0.05) mRNAs was more abundant in the small than the large antral follicles of Black Bengal goat. The more numbers of antral follicles per unit of ovarian mass and differential expression of BMP15 and GDF9 may serve as an important clue for higher prolificacy.  相似文献   
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