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1.
ABSTRACT:   Parvalbumin is a sarcoplasmic Ca2+-binding protein of 12 kDa and represents the major fish allergen. Several peptide segments are identified as immunoglobulin E (IgE)-binding epitopes of cod parvalbumin. However, carp parvalbumin (Cyp c 1) shows a markedly reduced IgE-binding ability upon depletion of Ca2+, suggesting the importance of conformational epitopes associated with Ca2+-chelating. In this study, the IgE reactivity of Pacific mackerel Scomber japonicus parvalbumin (Sco j 1) was demonstrated to be markedly reduced (60–100% reduction) by Ca2+-depletion, similar to Cyp c 1. Three Sco j 1 mutants (D51A, D90A, D51/90A), with modifications in either one or both of the two Ca2+-binding sites, were then constructed by site-directed mutagenesis, followed by expression in Escherichia coli , and evaluated for their IgE reactivity. Interestingly, the double mutant (D51/90A), probably devoid of Ca2+-binding capacity, exhibited a significantly reduced IgE reactivity (equivalent to 0.0–7.5% of the IgE reactivity of natural Sco j 1). The results suggest that the IgE-binding ability of Sco j 1 largely depends on the solid conformation mediated by Ca2+-chelating, and that the hypoallergenic D51/90A will be a useful tool for the specific immunotherapy of fish allergy.  相似文献   

2.
Associations between catches and depth, temperature and salinity data obtained from the 1994–97 preseason shrimp trawl surveys in Kuwait waters were analysed using cumulative distribution functions and overlap coefficients. No single environmental factor had a controlling influence on shrimp distribution. Shrimp associations with the joint distributions of two environmental variables were stronger and more consistent over time than those with any single environmental factor. All three shrimp species examined in this study were significantly associated with the joint distributions of depth and temperature, and depth and salinity, indicating depth as the most influential factor in structuring the shrimp distributions during the surveys. Metapenaeus affinis and Parapenaeopsis stylifera were distributed at similar ranges of depth (8–15 m), temperature (26–31°C) and salinity (35–41‰), and had very high overlap coefficients. These two species can be categorized as co-occurring species in the sampled area. Penaeus semisulcatus had the widest range of the three environmental variables investigated in this study, particularly depth (8–32 m) and temperature (24–32°C).  相似文献   

3.
ABSTRACT:   To utilize fisheries waste products as food materials with functional properties, shrimp head protein hydrolysates (SHPH) from three species of shrimp, that is, Northern pink shrimp ( Pandalus eous ), Endeavour shrimp ( Metapenaeus endeavouri ) and Black tiger shrimp ( Penaeus monodon ), were produced by enzymatic hydrolysis using endopeptidase derived from Bacillus subtilis and exopeptidase derived from Aspergillus oryzae at a level of 0.1% (w/w). SHPH were rich in protein (90–91%) and amino acids (71–84%) but little fat (0.01–0.02%). The average molecular weight of SHPH was 300–1400. The effect of 5% SHPH (dry basis) addition on the state of water and denaturation of lizard fish myofibrils (Mf) during the dehydration process was evaluated by the desorption isotherm and the Ca-ATPase activity, and compared with the effect of sodium glutamate (Na-Glu). SHPH decreased the water activity and the Ca-ATPase inactivation, and increased monolayer sorbed water and multilayer sorbed water of Mf, although these effects of SHPH were smaller than those of Na-Glu. These findings suggest that the SHPH suppressed dehydration-induced denaturation of myofibrillar protein by stabilizing the hydrated water surrounding myofibrils.  相似文献   

4.
Abstract. Yellow head baculo-like virus infection and disease were demonstrated experimentally in the two main species of penaeid shrimp cultured in Hawaii and the Western hemisphere. Viral infection was induced by intramuscular inoculation of a 10% suspension of cephalothorax tissue filtrate prepared from two tiger shrimp, Penaeus monodon Fabricius, infected with yellow head disease, into sub-adult (3–10g) P. stylirostris (Stimpson) and P. vannamei (Boone). Signs of disease appeared as early as 2 days post infection (p.i.), and in most cases mortality reached 100% within 5–7 days p.i. Histopathological examination of the infected animals revealed extensive cellular necrosis in ectodermal and some mesenchymal tissues. Electron microscopical examination of thin sections of the gill and hepatopancreas from the infected shrimp revealed non-occluded rod-shaped baculo-like virus particles measuring 130–197 & 45–58 nm which were primarily localized within the cytoplasm of infected cells. The virus particles were contained within cytoplasmic vacuoles, and occurred singly or in small groups of two or more particles.  相似文献   

5.
6.
以超低温保存的感染了白斑综合征病毒(WSSV)的中国对虾制备的病毒粗提液为毒种,注射感染凡纳对虾并收集濒死虾,DNA斑点杂交检测每尾凡纳对虾WSSV感染状况。取DNA斑点杂交呈强阳性的30尾对虾,平均分为3组,病毒粗提液也平均分成3组,3组材料分别通过^60Co辐照,辐照时间分别为12、24和36h,辐照剂量为0.8KGy/h。辐照后的材料经PCR检测证实^60Co辐照不能完全破坏WSSV的DNA组成。以辐照后的感染白斑综合征病毒的对虾个体和白斑综合征病毒粗提液为感染毒种,人工感染健康凡纳对虾,验证^60Co辐照对病毒感染力的破坏作用,证实^60Co辐照可显著降低WSSV病毒粗提液的感染力,^60Co辐照可适当降低WSSV感染对虾的感染力。  相似文献   

7.
Abstract

The objective of this study was to determine the potential for transmission of aflatoxin B1 to humans through consumption of shrimp contaminated with this toxin. Pacific white shrimp (Penaeus vannamei) were fed diets dosed with three levels of afaltoxin B1 (300, 400, and 900 ppb) in an 8 week indoor aquarium feeding trial. The shrimp were analyzed for residues of the toxin in the feces, whole shrimp and tail muscle after concentrating the aflatoxin by monoclonal antibody affinity chromatography, followed by radioimmunoassay. Aflatoxin B1 was not detected in shrimp feces, whole shrimp or tail muscle within detection limits of 2 ppb. Our study suggests that the possibilities for aflatoxin B1 toxicity occurring in humans via consumption of shrimp fed on diets contaminated with this toxin are limited.  相似文献   

8.
Abstract. Infectivity experiments were undertaken by water-borne inoculation of kuruma shrimp, Penaeus japonicus Bate, larvae with BMN virus. Mysis stage larvae were inoculated with the virus by exposure for 2h in sea water containing a homogenized and filtered preparation (450nm) of naturally BMN virus-infected shrimp stored for about 7 weeks at −80°C. Inoculated shrimp stocked in rearing jars were examined to determine whether nuclear hypertrophy of the mid-gut gland epithelial cells characteristic for BMN virus infection could be observed in fresh squash preparations under dark field illumination equipped with a wet-type condenser. Four days post-inoculation at 25–30°C incubation temperature were considered to be satisfactory for the experimental trial.  相似文献   

9.
Retention efficiency and release of the nutrients in the digestive tract of larval shrimp (Penaeus japonicus) using the diets microencapsulated with gelatin and ethyl cellulose respectively were evaluated. The microencapsulated diets were produced using the fluidized bed coating process. 7.8 % gelatin and 4.2 % ethyl cellulose to the whole microencapsulated diet were respectively adopted as coating material. After immersion in 35 ‰ NaCl solution for 1 h, the nitrogen retention efficiency was significantly lower in the diet microencapsulated with gelatin compared with the diet microencapsulated with ethyl cellulose. Free amino acid retention efficiency of the diet microencapsulated with gelatin and ethyl cellulose was 12.9, 17.2 %, respectively. The mysis II larval shrimp (P. japonicus) 10 days after hatch were fed two different microencapsulated diets for 20 days and grew significantly more than the control larval shrimp fed with Artemia and shrimp flake. The nutrient components in intermediate intestine of larval shrimp were increased gradually in the order of the control (50 % shrimp flake + 50 % Artemia), Group I (50 % diet microencapsulated with gelatin + 25 % shrimp flake +25 % Artemia), Group II (100 % diet microencapsulated with gelatin), and Group III (100 % diet microencapsulated with ethyl cellulose). This study confirmed that the microencapsulated diets with slow and controlled release characteristic in the digestive tract of the larval shrimp (P. japonicus).  相似文献   

10.
A study was conducted on the stability of monoclonal antibody (MAb) in the hepatopancreas and hemolymph of Penaeus monodon and its effect on protection against white spot syndrome virus (WSSV) upon challenge. MAb C-5 raised against WSSV was purified and coated onto a commercial shrimp feed at dosages of 5, 10 and 15 mg/kg feed. The feed was fed to P. monodon and stability of the MAb in hepatopancreas and hemolymph was determined by immunodot and Western blot. Immunodot results indicated the presence of MAb for 2 h post-feeding in hepatopancreas and hemolymph which was dose-dependent. MAb was also detected in hemolymph by Western blot up to 1 h post-feeding. Shrimp fed with MAb were challenged with WSSV by oral and injection methods. In shrimp fed with 15 mg antibody/kg feed (0.45 μg MAb/g shrimp/day) WSSV infection significantly delayed both in oral and injection challenges with a survival of 65 and 70 % (p < 0.05), respectively, during 15 days post-challenge. MAb was stable in shrimp for passive immunization against WSSV and could be a potential tool for prophylaxis against the virus.  相似文献   

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