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PubMed2002

Usefulness of dead shrimp specimens in studying the epidemiology of white spot syndrome virus (WSSV) and chronic bacterial infection.

This paper describes the utility of dead shrimp samples in epidemiological investigations of the white spot syndrome virus (WSSV) and chronic bacterial infections. A longitudinal observational study was undertaken in shrimp farms in Kundapur, Karnataka, India, from September 1999 to April 2000 to identify risk factors associated with outbreaks of white spot disease (WSD) in cultured Penaeus monodon. As a part of the larger study, farmers were trained to collect and preserve dead and moribund shrimp (when observed) during the production cycle. At the end of the production cycle, 73 samples from 50 ponds had been collected for histopathology and 55 samples from 44 ponds for PCR. Intranuclear viral inclusion bodies diagnostic of WSSV infection were detected in dead samples from 32 ponds (64 %). Samples of dead shrimp from 18 ponds (36%) showed no histopathological evidence of WSSV infection. However, of these, samples from 13 ponds (26%) showed clear evidence of shell, oral, enteric and systemic chronic inflammatory lesions (CIL) in the form of haemocytic nodules, typical of bacterial infection. Samples from 5 ponds (10%) were negative for both WSSV and CIL. Samples from 8 ponds had dual WSSV and CIL, although both WSSV and CIL were only observed in the same shrimp from 1 pond. Useful information was obtained from these shrimp despite the presence of post-mortem changes. Samples from 19 ponds (43%) tested positive for WSSV by 1-step PCR and samples from an additional 10 ponds (22.7%) were positive by 2-step nested PCR. Samples from 15 ponds (34.1%) were negative for WSSV by 2-step nested PCR. There was moderate to substantial agreement between PCR and histopathology in the diagnosis of WSSV infection in dead shrimp. WSSV infection in dead shrimp was significantly associated with crop failures as defined by a shorter length of the production cycle (<90 d) and lower average weight at harvest (<22 g). WSSV infection was also associated with lower survival (<50%), but this was not significant. Ponds with CIL did not experience any crop failures, and the presence of CIL was significantly associated with successful crops. The study demonstrates that samples of dead shrimp can provide useful information for disease surveillance and epidemiological investigations of WSSV and chronic bacterial infections.

Animals↗

PubMed2004

Safety and protective effect of a disinfectant (STEL water) for white spot syndrome viral infection in shrimp.

The efficacy of STEL water for protection against white spot syndrome virus (WSSV) infection was evaluated using shrimp. The LC50 of residual chlorine (Cl-) in STEL water for brood-stock and 2-mo-old shrimp were 2.3 and 3.2 ppm, respectively. All 2-month-old shrimp raised in seawater containing more than 40 microl 2l(-1) of a WSSV-infected tissue homogenate died within 3 d post-exposure (dpe). Thus, a 10-fold dose of 400 microl 2 l(-1) was used in the disinfection tests. Low concentrations of STEL water effectively prevented mortality of shrimp at this challenge dose. All 2-month-old shrimp exposed to seawater with 400 microl of viral homogenate disinfected with STEL water at Cl- concentrations over 0.125 ppm for 1 and 10 min, lived until 5 dpe. With 5-mo-old shrimp, all positive control shrimps died within 3 dpe, whereas most shrimp reared in seawater disinfected with STEL water for 1 h before addition of homogenate lived until 5 dpe. Results suggested that continuous disinfection of seawater with STEL water may be effective for preventing WSSV infection in shrimp.

Animals↗

PubMed2005

Bacterial clearance rate and a new differential hemocyte staining method to assess immunostimulant activity in shrimp.

New methods were developed to assess immunostimulant efficacy in the black tiger shrimp Penaeus monodon. Test shrimp were fed with 2 or 4 % yeast extract (YE)-coated feed while controls were fed non-coated feed. After 4 wk of feeding, individual shrimp were assessed for total hemocyte counts (THC), the number of granular hemocytes (GH) and rate of bacterial clearance. For hemocyte counts, formalin-fixed hemolymph was stained with 1.2 % Rose Bengal in 50 % ethanol for 20 min at room temperature. Some of this mixture was used for THC with a hemocytometer while some was smeared on a microscope slide and left to dry before counterstaining with hematoxylin for GH counts. By this technique, high quality smears were obtained for accurate differential counts. Bacterial clearance assays were used to assess the sum effect of humoral and cellular defense mechanisms. Vibrio harveyi was injected intramuscularly at 1 x 10(8) cells per shrimp and hemolymph was collected in anticoagulant at 0, 15, 30 and 60 min post-injection for quadruplicate drop counts (20 microl) on TCBS agar. Total hemocyte counts for shrimp fed with 4 % YE were significantly higher (p < 0.05) than those for shrimp fed with non-coated feed. The percentage of granular cells and the rates of bacterial clearance for the YE-fed shrimp were higher than those for shrimp fed the control diet. These 2 methods provide a simple and rapid comparison of shrimp groups for differences in anti-bacterial defense capacity.

Analysis of Variance↗

PubMed1981

The major heat stable allergen of shrimp.

Serum from a patient who had experienced several episodes of anaphylaxis after eating shrimp was used to monitor the isolation of a major allergen from shrimp, which was then tested with sera from 10 other shrimp-reactive patients. The allergen was isolated from a fresh extract of boiled shrimp by gel filtration and from raw shrimp by gel filtration and agarose electrophoresis. The purity of the allergen was established by crossed immunoelectrophoresis against rabbit and guinea pig antisera; it gave only a single peak in each case. The native allergen was excluded on Sephadex G-200 but showed a single band at 38000d in SDS-PAGE with or without reduction. The isoelectric point was about 4.5. The allergen contained about 4% carbohydrate and only 7 Tyr and 9 Phe out of 341 amino acid residues. Using the RAST with 11 allergic sera, the allergen gave a correlation coefficient of 0.98 with whole cooked shrimp extract and of 0.66 with raw shrimp extract. The allergen was a potent inhibitor of RAST to both cooked and raw shrimp. A second, weaker allergen of 21000d chain size was isolated from raw shrimp in highly purified form.

Allergens↗

PubMed1993

Identification of tropomyosin as the major shrimp allergen and characterization of its IgE-binding epitopes.

The major heat-stable shrimp allergen (designated as Sa-II), capable of provoking IgE-mediated immediate type hypersensitivity reactions after the ingestion of cooked shrimp, has been shown to be a 34-kDa heat-stable protein containing 300 amino acid residues. Here, we report that a comparison of amino acid sequences of different peptides generated by proteolysis of Sa-II revealed an 86% homology with tropomyosin from Drosophila melanogaster, suggesting that Sa-II could be the shrimp muscle protein tropomyosin. To establish that Sa-II is indeed tropomyosin, the latter was isolated from uncooked shrimp (Penaeus indicus) and its physicochemical and immunochemical properties were compared with those of Sa-II. Both tropomyosin and Sa-II had the same molecular mass and focused in the isoelectric pH range of 4.8 to 5.4. In the presence of 6 M urea, the mobility of both Sa-II and shrimp tropomyosin shifted to give an apparent molecular mass of 50 kDa, which is a characteristic property of tropomyosins. Shrimp tropomyosin bound to specific IgE antibodies in the sera of shrimp-sensitive patients as assessed by competitive ELISA inhibition and Western blot analysis. Tryptic maps of both Sa-II and tropomyosin as obtained by reverse phase HPLC were superimposable. Dot-blot and competitive ELISA inhibition using sera of shrimp-sensitive patients revealed that antigenic as well as allergenic activities were associated with two peptide fractions. These IgE-binding tryptic peptides were purified and sequenced. Mouse anti-anti-idiotypic antibodies raised against Sa-II specific human idiotypic antibodies recognized not only tropomyosin but also the two allergenic peptides, thus suggesting that these peptides represent the major IgE binding epitopes of tropomyosin. A comparison of the amino acid sequence of shrimp tropomyosin in the region of IgE binding epitopes (residues 50-66 and 153-161) with the corresponding regions of tropomyosins from different vertebrates confirmed lack of allergenic cross-reactivity between tropomyosins from phylogenetically distinct species.

Allergens↗

PubMed1995

[Survey of disease of cultural shrimp in Taiwan].

The large number of hemocytes infiltrated several abnormal tissues of kuruma shrimp (Penaeus japonicus), including musculature, hepatopancreas, lymphoid organ, gill filament and sponge tissue. In addition, there were many denatured hemocytes existing inside acidophilic particles and forming granules. Futhermore, in hepatopancreas of kuruma shrimp, a white spot baculovirus (WSBV; 40-50 x 50-300 nm) was discovered in UH (undifferential haemocyte). The epithelium cells, which including stomach cuticle and underlying epidermis of exoskeletal cuticle, could also be infected by WSBV in another main cultural species--grass shrimp (P. monodon). During a period of high water temperature, with pond shrimp in normal condition, the CFU/ml of water bacteria rose from 10(5) to 10(7), but this number had decreased to 10(5) CFU/ml by the time moribund shrimp began to appear. Coincidentally, the total bacterial number isolated from hepatopancreas and musculature of moribound shrimp was over 10(5) (CFU/g) and 10(3)-10(5), respectively. The fauna of bacteria was taken over by the active metabolitic species which were represented by Vibrio species causing the pond shrimp to undergo either behavioral changes, such as swimming on the water surface, or histological changes, such as having whitish muscle color, hemocyte infiltration and granuloma formation etc. Pathogenetic species of Vibrio including V. parahaemolyticus, V. alginoly ticus V. anguillarum, V. fischery and V. damsela were isolated from those tissues of moribund shrimp. The main pathogens, isolated from musculature and hepatopancreas, were V. parahaemolyticus and V. alginolyticus. On the other hand there, was no bacterium could be isolated from the musculature of healthy shrimp and only a single species of Gram (+) coccus--Micrococcus--was isolated from the tissue of hepatopancreas.

Animals↗

PubMed1996

Establishment and Persistence of Baculovirus penaei Infections in Cultured Pacific White Shrimp, Penaeus vannamei

The time course for establishment of a baculovirus (BP) infection and the persistence of infections in larvae and postlarvae of the Pacific white shrimp, Penaeus vannamei was investigated. In two preliminary studies, postlarvae were inoculated with BP and the prevalence of infections was monitored over 138- and 73-day periods. Viral polyhedra characteristic of patent infections first appeared 24 hr after inoculation, were present in all shrimp examined 14-17 days postinoculation (p.i.), and then decreased in prevalence during the remainder of each study. BP infections could not be detected by in situ hybridization in shrimp collected during the final day of each study. In a third and more comprehensive study, PCR-based diagnostic procedures were used to detect BP in experimentally infected shrimp over a 120-day period. In that study, BP was first detected in viral exposed mysis stage shrimp 12 hr p.i., was present in all shrimp examined by 72 hr p.i., and decreased in prevalence during the remainder of the study. BP infections could not be detected by PCR-based diagnostics in shrimp collected on the final day of the study. Only 1 of 10 previously infected shrimp collected at 31 days p.i. and diagnosed for BP by bioassay was infected. Results of this study indicate similarities between P. vannamei and some species of insects in the time required for establishment and loss of a patent baculovirus infection.

Journal Article↗

PubMed1996

Issues, Impacts, and Implications of Shrimp Aquaculture in Thailand

Water quality impacts to and from intensive shrimp aquaculture in Thailand are substantial. Besides the surface and subsurface salinization of freshwaters, loadings of solids, oxygen-consuming organic matter, and nutrients to receiving waters are considerable when the cumulative impacts from water exchange during the growout cycle, pond drainage during harvesting, and illegal pond sediment disposal are taken into account. Although just beginning to be considered in Thailand, partial recirculating and integrated intensive farming systems are producing promising, if somewhat limited, results. By providing on-site treatment of the effluent from the shrimp growout ponds, there is less reliance on using outside water supplies, believed to be the source of the contamination.The explosion in the number of intensively operated shrimp farms has not only impacted the coastal zone of Thailand, but has also resulted in an unsustainable aquaculture industry. Abandonment of shrimp ponds due to either drastic, disease-caused collapses or more grandual, year-to-year reductions in the productivity of the pond is common. To move Thailand towards a more sustainable aquaculture industry and coastal zone environment, integrated aquaculture management is needed. Components of integrated aquaculture management are technical and institutional. The technical components involve deployment of wastewater treatment and minimal water-use systems aimed at making aquaculture operations more hydraulically closed. Before this is possible, technical and economic feasibility studies on enhanced nitrification systems and organic solids removal by oxidation between production cycles and/or the utilization of plastic pond liners need to be conducted. The integration of semi-intensive aquaculture within mangrove areas also should be investigated since mangrove losses attributable to shrimp aquaculture are estimated to be between 16 and 32 % of the total mangrove area destroyed betweeen 1979 and 1993.Government policy needs to devote as much attention to sustainability issues as it has on promoting intensive pond culture. Such a balanced policy would include training and education monitoring and enforcement, rehabilitating abandoned ponds, managing land use within the coastal zone, more community involvement, and government reorganization to eliminate overlapping jurisdictions among agencies.As integrated aquaculture management becomes more the practice than the exception, less risk of crop failure to the industry and reduced discharge loadings from intensively managed shrimp ponds to receiving waters can be expected. Projected limitations on growing and marketing shrimp in the future, such as scarcity of land and broodstock, continued disease outbreaks, negative publicity, regulatory enforcement, water treatment and solids disposal costs, and increased competition from growers in other Asian countries will also drive the government and the industry towards adopting integrated aquaculture management.KEY WORDS: Shrimp aquaculture; Thailand; Historical practices; Environmental impacts; Sustainability; Integrated management; Water treatment; Institutional aspects

Journal Article↗

PubMed2006

Effects of copper, cadmium, and zinc on the hatching success of brine shrimp (Artemia franciscana).

Previous studies indicate that the hatching success of brine shrimp (Artemia franciscana) cysts is surprisingly sensitive to ambient metal concentrations. These studies estimated median effective concentrations (EC50s) of 7, 5, and 28 microg l-1 for Cd, Cu, and Zn, suggesting that the hatching end point for A. franciscana is the most sensitive tested to date for Cd and Zn in saline environments and comparable in sensitivity with the most sensitive tested to date for Cu. Furthermore, these data suggest that brine shrimp are at significant risk from Cu and Zn in Great Salt Lake (GSL), UT, where ambient concentrations as high as 10 and 14 microg l-1, respectively, have been measured. Given that brine shrimp appear to be successfully reproducing in GSL, we hypothesized that these toxicity values were either biased low as a result of an artifact of the test method used or that site-specific water-quality conditions in the lake had decreased metal bioavailability such that brine shrimp could successfully reproduce. To test these hypotheses, we initiated a step-wise series of experiments. First we investigated the effects of pretreatment of brine shrimp cysts with antibiotics on brine shrimp sensitivity to metals because previous investigators as part of their test methods have used antibiotics. Next we considered the effect of ionic composition of the artificial test media on sensitivity. Finally, we evaluated the effects of the site-specific water quality of the GSL on metal bioavailability and toxicity. Results indicate that pretreatment of cysts with antibiotics had no effect on sensitivity. However, we were unable to repeat the previous values for Cd and Zn, obtaining EC50s of 11,859 and 289 microg l-1 for Cd and Zn, respectively. For Cu, however, we estimated an EC50 of 12 microg l-1, so we conducted further testing on the artificial media, adjusting the media composition to better reflect the Ca2+ and HCO3- concentration of normal seawater. This increased the EC50 to 28 microg l-1. Finally we evaluated the toxicity of Cu in GSL water and obtained an EC50 of 68 microg l-1, suggesting that the increased dissolved organic carbon in GSL has a significant protective effect. Overall, the results of this study suggest that brine shrimp hatching success is not particularly sensitive to Cd and Zn, but it is sensitive to Cu. However, site-specific water-quality conditions ensure that brine shrimp cyst hatching success is not significantly affected by any of these metals at the normal background concentrations that occur in GSL (<15 microg l-1).

Animals↗

PubMed1990

Shrimp hepatopancreatic deoxyribonuclease--purification and characterization as well as comparison with bovine pancreatic deoxyribonuclease.

Deoxyribonuclease (DNase), isolated from shrimp hepatopancreas by chromatography on DEAE-cellulose, Sephadex G-100, phenyl-Sepharose and hydroxyapatite, is homogeneous as shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The metal ion requirements and the pH-activity optima of shrimp DNase are very similar to those of bovine DNase. Both shrimp and bovine DNases are sensitive to iodoacetate inactivation under the same condition. The active shrimp DNase molecule is a monomer of Mr 44,000, approx. 13,000 larger than the Mr of bovine DNase. Shrimp DNase is rich in glutamic acid, glycine and half-cystine. The single polypeptide chain of shrimp DNase is highly cross-linked by 18 disulfides as compared to only two disulfides in bovine DNase. In contrast to bovine DNase, shrimp DNase is not a glycoprotein, is devoid of the activity against p-nitrophenyl phenylphosphonate (a synthetic substrate for bovine DNase), and resists to inactivation by beta-mercaptoethanol or trypsin under the Ca2(+)-free condition at pH 8. Shrimp DNase shows an isoelectric point of 4.06 on the thin-layer isoelectric focusing and rapidly loses its activity at pH below 5.

Amino Acids↗

PubMed2005

Viral resistance in shrimp that express an antisense Taura syndrome virus coat protein gene.

Taura syndrome virus (TSV) is a major cause of mortality and morbidity in shrimp, and has a profound economic impact on commercial U.S. shrimp farming. This paper describes the stable expression of an antisense Taura syndrome virus-coat protein (TSV-CP) gene construct in shrimp zygotes, via transfection using jetPEI reagent, over a period of at least 236 days. The transgenic shrimp showed no statistically significant difference from normal control shrimp in terms of weight gain or their appearance, morphology, swimming and eating activities. When challenged with live TSV, the transgenic shrimp exhibited increased resistance to the TSV infection (83% survival rate) as compared to control animals (44% survival rate). This work demonstrates that transgenic shrimp, which stably express an antisense transcript from the TSV-CP gene, are partially resistant to TSV infection. These data may have an important implication for commercial shrimp farming.

Animals↗

PubMed2005

Preliminary studies of biochemical changes (ethoxycoumarin O-deethylase activities and vitellogenin induction) in two species of shrimp (Farfantepenaeus duorarum and Litopenaeus setiferus) from the Gulf of Mexico.

Several investigations have demonstrated that the increase in chemicals in the environment may have caused effects on aquatic life and wildlife. The impact from oil production activities on the benthic community structure and shrimp (Farfantepenaeus duorarum and Litopenaeus setiferus) biochemical markers were studied in the Gulf of Mexico, which is heavily contaminated by polycyclic aromatic hydrocarbons and heavy metals. Shrimp were collected from a control area and from an area close to oil production platforms during October and November 2002. There was no spatial difference in exposure and response probably because shrimp migrate, as results did not show significant differences in cytochrome P4501A (as measured by ethoxycoumarin O-deethylase (ECOD) metabolism) between the two sites. In October, shrimp ECOD activities were higher and statistically different from those measured in the samples taken in November. As for ECOD activities, with the concentration of vitellogenin as another biomarker, there were no differences between the shrimp collected from the control area and the shrimp collected on the oil production platforms. In this case the concentrations were higher in shrimp collected in November vs. shrimp collected in October. However, there are significant correlations between contaminants and responses (biomarkers), indicating an effect of pollution. One of the most important considerations brought up by this kind of study is that, although the majority of groups studying the effects of endocrine disruption have focused almost exclusively on human health or vertebrate wildlife-related issues, it is necessary to increase research focused on understanding the function of hormones in invertebrate species exposed in the field to different kinds of pollutants.

7-Alkoxycoumarin O-Dealkylase↗

PubMed2004

Vitamin E requirements of juvenile grass shrimp, Penaeus monodon, and effects on non-specific immune responses.

A feeding trial was conducted to determine the dietary vitamin E (DL-alpha-tocopheryl acetate, dl-alpha-TOA) requirement and its effect on the non-specific immune responses of juvenile grass shrimp, Penaeus monodon. Purified diets with eight levels (0, 25, 50, 75, 100, 150, 200, 400 mg vitamin E kg diet-1) of supplemental dl-alpha-TOA were fed to P. monodon (mean initial weight 0.29 +/- 0.01 g) for eight weeks. Each diet was fed to three replicate groups of shrimp. Weight gains and total haemocyte count (THC) were higher (P < 0.05) in shrimp fed diets supplemented with 75 and 100 mg vitamin E kg diet-1 than in shrimp fed diets supplemented with </= 50 mg vitamin E kg diet-1. Superoxide dismutase (SOD) activity was higher in shrimp fed diets supplemented with 50-200 mg vitamin E kg diet-1 than in shrimp fed diets supplemented with </= 25 and 400 mg vitamin E kg diet-1. Vitamin E concentrations in the hepatopancreas and muscle of the shrimp were increased as the dietary vitamin E supplementation level was increased up to 200 mg vitamin E kg diet-1. Thiobarbituric acid (TBA) values in the hepatopancreas and muscle were generally decreased as the dietary vitamin E supplementation level increased. Analysis by polynomial regression of weight gain, THC and hepatopancreatic vitamin E concentration of the shrimp indicated that a level of 85-89 mg vitamin E kg diet-1 is required for maximal growth and non-specific immune responses of P. monodon and that 179 mg vitamin E kg diet-1 is required to maximise tissue vitamin E concentration.

Analysis of Variance↗

PubMed2005

The immune response of white shrimp Litopenaeus vannamei and its susceptibility to Vibrio alginolyticus at different salinity levels.

White shrimp Litopenaeus vannamei held in 25 per thousand seawater were injected with TSB-grown Vibrio alginolyticus (1 x 10(4) cfu shrimp(-1)), and then transferred to 5, 15, 25 (control) and 35 per thousand. Over 24-96 h, the mortality of V. alginolyticus-injected shrimp held in 5 per thousand and 15 per thousand was significantly higher than that of shrimp held in 25 per thousand and 35 per thousand, and the mortality of V. alginolyticus-injected shrimp held in 5 per thousand was the highest. Shrimp held in 25 per thousand and then transferred to 5, 15, 25 (control) and 35 per thousand were examined for THC (total haemocyte count), phenoloxidase activity, respiratory burst, superoxide dismutase (SOD) activity, phagocytic activity and clearance efficiency to V. alginolyticus after 12-72 h. The THC, phenoloxidase activity, respiratory burst, SOD activity, phagocytic activity and clearance efficiency decreased significantly for the shrimp held in 5 and 15 per thousand after 12 h. It is concluded that the shrimp transferred from 25 per thousand to low salinity levels (5 and 15 per thousand) had reduced immune ability and decreased resistance against V. alginolyticus infection.

Animals↗

PubMed2006

Profiling of differentially expressed genes in hepatopancreas of white spot syndrome virus-resistant shrimp (Litopenaeus vannamei) by suppression subtractive hybridisation.

In order to find immune-relevant factors responsible for virus resistance and response to the virus infection, the suppression subtractive hybridisation method was employed to identify differentially expressed genes and their expression profiles in the hepatopancreas of the white spot syndrome virus (WSSV) resistant and susceptible Pacific white shrimp (Litopenaeus vannamei). Two forward subtractive libraries (at 0 and 48h time point) and two reverse subtractive libraries (at 0 and 48h time point) were constructed, and more than 1200 clones were sequenced, of which 40 differentially expressed genes were identified. These genes encode proteins corresponding to a wide range of functions, including defence-related proteins, enzymes, transcription factors, apoptotic-related proteins, intracellular components potentially related to signaling cascades, metabolic proteins, and cytoskeletal protein. Five genes (laccase, carboxypeptidase B, H(+)-transporting ATP synthase, Acyl-ConA-binding protein (ACBP), and cortical granule protein with LDL-receptor) are found for the first time in shrimp and their expressions were up-regulated in the virus-resistant shrimp. Among the 40 genes, 30 showed up-regulation in the virus-resistant shrimp comparing with susceptible shrimp, while 10 genes showed down-regulation. Haemocyanin was the most abundant gene in our forward subtractive libraries. In addition, chathepsin L, ecdysteroid regulated protein, zinc proteinase, lectin, sterol carrier protein-X, lysozyme, cortical granule protein with LDL-receptor, leucine-rich repeat LGI family, fatty acid binding protein, and preamylase all showed up-regulation in the resistant shrimp. Furthermore, a number of genes encoding apoptotic-related proteins and antioxidant enzymes were expressed at a higher level in the virus-resistant shrimp. The high expression of the immune-relevant genes in response to the virus infection provides a new insight for further study in the shrimp innate immunity.

Amino Acid Sequence↗

PubMed2006

Studies on nitric oxide synthase activity in haemocytes of shrimps Fenneropenaeus chinensis and Marsupenaeus japonicus after white spot syndrome virus infection.

The nitric oxide synthase (NOS) activity in the haemocytes of shrimps Fenneropenaeus chinensis (Osbeck) and Marsupenaeus japonicus (Bate) was studied after white spot syndrome virus (WSSV) infection to determine its characteristics in response to virus infection. First, the NOS activity in haemocytes of shrimps was determined by the means of NBT reduction and changes in cell conformation. And the variations of NOS activity in shrimps after challenge with WSSV intramuscularly were evaluated through the analysis of L-citrulline and total nitrite/nitrate (both as NO derivates) concentrations. The result showed that NOS activity in the haemocytes of F. chinensis increased slightly from 0 to 12h postchallenge, indicated by the variations of l-citrulline (from 11.15+/-0.10 to 12.08+/-0.64 microM) and total nitrite/nitrate concentrations (from 10.45+/-0.65 to 12.67+/-0.52 microM). Then it decreased sharply till the end of the experiment (84 h postchallenge), the concentrations of l-citrulline and total nitrite/nitrate at 84 h were 1.58+/-0.24 and 2.69+/-0.70 microM, respectively. The LPS-stimulated NOS activity kept constant during the experiment. However, in M. japonicus, the NOS activity kept increasing during the first 72 h postchallenge, the concentrations of l-citrulline and total nitrite/nitrate increased from 7.82+/-0.77 at 0 h to 10.79+/-0.50 microM at 72 h, and from 8.98+/-0.43 at 0 h to 11.20+/-0.37 microM at 72 h, respectively. Then it decreased till the end of the experiment (216 h postchallenge), and the concentrations of l-citrulline and total nitrite/nitrate at 216 h were 5.66+/-0.27 and 4.68+/-0.16 microM, respectively. More importantly, an apparent increase of LPS-stimulated NOS activity was observed in M. japonicus at 48 h postchallenge, which was about 4 times higher than that in the control group of health shrimps. In correspondence with the difference of NOS activity between the two species of shrimps, the cumulative mortalities of the shrimps were also different. All shrimps of F. chinensis in the mortality experiment died in 66 h, much more quickly than M. japonicus, whose accumulative mortality reached 100% after 240 h. Data here reported let us hypothesize that NOS activity in the haemocytes of shrimps F. chinensis and M. japonicus responses to WSSV infection differently, and this might be one of the reasons for the different susceptibility of F. chinensis and M. japonicus to WSSV infection.

Animals↗

PubMed1998

The shrimp hyperglycemic hormone-like neuropeptide is encoded by multiple copies of genes arranged in a cluster.

The crustacean hyperglycemic hormone (CHH) plays an important role in the regulation of glucose metabolism. We have cloned and sequenced several cDNAs encoding the preproCHH-like of the shrimp, Metapenaeus ensis. The preproCHH-like peptide of the shrimp consists of a signal peptide, a CHH precursor-like peptide (CPRP) and the CHH-like peptide. Comparative analysis revealed that the signal peptide and the CPRP of the shrimp peptide are the shortest among all the CHHs reported. MeCHH-like is expressed in the eyestalk, but it is not expressed in the heart, hepatopancreas, muscle, nerve cord and pre-hatch embryo. To study the structural organization of the shrimp CHH-like gene, we have screened the genomic DNA library constructed from one shrimp. Three groups of overlapping genomic clones have been isolated. The results from both genomic Southern blot analysis and library screening indicate that the shrimp genome contains at least six copies of the CHH-like genes arranged in a cluster on the chromosome. The size of the CHH-like genes is 1.5-2.1 kb. DNA sequence determinations indicate that the CHH-like genes share 98-100% amino acid sequence identity. There are three exons and two introns in each CHH-like gene. The first intron separates the signal peptide and the second intron separates the mature peptide in the coding region. The 150-200 bp of the upstream 5' flanking region of the CHH-like genes contains promoters with characteristics similar to most eukaryotic genes. Several putative cis-acting elements are also identified in the first 400 bp 5' end upstream region. The organization of the shrimp CHH-like genes is similar to that of the molt inhibiting hormone gene of the same shrimp and the crab, Charybdis feriatus.

Amino Acid Sequence↗

PubMed2003

Characterization and function of kuruma shrimp lysozyme possessing lytic activity against Vibrio species.

Lysozyme cDNA was isolated from a kuruma shrimp, Marsupenaeus japonicus, hemocyte cDNA library. The cDNA consists of 1055 base pairs (bp) and encodes a chicken-type (c-type) lysozyme with a deduced amino acid sequence of 156 residues. The kuruma shrimp lysozyme has a high identity (79.7%) with pacific white shrimp lysozyme, and low to moderate identities (33.3-43.0%) with lysozymes of insects and vertebrates. Comparisons with other c-type lysozymes from invertebrates and vertebrates showed that the two catalytic residues (Glu58 and Asp75) and the eight cysteine residue motif were completely conserved. Two novel insertion sequences were also observed in the kuruma and pacific white shrimp lysozyme amino acid sequences. Interestingly, phylogenetic analysis revealed that the kuruma shrimp lysozyme was more closely related to vertebrate c-type lysozymes. Expression of the cDNA in insect cells, using a baculovirus expression system, yielded a recombinant lysozyme with optimum activity at pH 7.5 and 50 degrees C, as evaluated by a lysoplate assay. The kuruma shrimp lysozyme displayed lytic activities against several Vibrio species and fish pathogens, including Vibrio penaeicida (a pathogenic bacteria to the kuruma shrimp) and suggested that shrimp lysozyme affects a greater variety of pathogens.

Amino Acid Sequence↗