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At least 163 records · Page 9Linked to original sources

PubMed2006

Silencing shrimp white spot syndrome virus (WSSV) genes by siRNA.

White spot syndrome virus (WSSV) is a major shrimp pathogen causing large economic losses all over the world. So far, however, there is no efficient approach to control this virus. RNA interference (RNAi), which has been applied to silence virus genes in eukaryotic organisms. In this investigation, a specific 21bp short interfering RNA (vp28-siRNA) targeting a major envelope protein gene (vp28) of WSSV was used to induce gene silencing in vivo in Penaeus japonicus shrimp. It was found that the transcription and expression of vp28 gene were silenced by the sequence-specific vp28-siRNA. However, the RNAi effect disappeared or significantly weakened even if one-nucleotide mutation existed in the vp28-siRNA. As revealed by quantitative PCR, the vp28-siRNA caused a significant reduction in viral DNA production of WSSV-infected shrimp. When treated with the vp28-siRNA, WSSV-infected shrimp had a reduced mortality rate. After three injections of the vp28-siRNA, the virus was completely eradicated from WSSV-infected shrimp. These findings suggest that RNAi is capable of silencing sequence-specific genes of WSSV and might constitute a new therapeutic strategy for WSSV infection in shrimp.

Animals↗

PubMed2004

Distribution of mercury in adult penaeid shrimps from Altata-Ensenada del Pabellón lagoon (SE Gulf of California).

The Altata-Ensenada del Pabellon lagoon system is located in the central part of Sinaloa state, NW Mexico. The major sources of pollution are represented by the waste effluents from the intensive agriculture and the urban sewage from the cities of Culiacán (population of 750000) and Navolato (population of 50000). In this lagoon system diverse penaeid shrimps occur; the crystal shrimp Farfantepenaeus brevirostris, the brown shrimp F. californiensis, the blue shrimp Litopenaeus stylirostris, the white shrimp L. vannamei and the Pacific seabob Xiphopenaeus kroyeri. With the purpose of knowing distribution and relative concentrations of Hg in the main tissues of penaeid shrimps, levels of Hg in five species from Altata-Enesenada del Pabellón lagoon on the SE Gulf of California were determined. Analysis were carried out by reducing mercury compounds after acid digestion reduction with SnCl(2) and detection by cold vapour atomic absorption. In general, hepatopancreas was the tissue where Hg was mostly accumulated, followed by muscle and exoskeleton. The sequence of Hg concentrations in the five species studied here for every tissue was: hepatopancreas L. vannamei>F. californiensis>L. stylirostris>F. brevirostris>X. kroyeri; muscle L. stylirostris>F. brevirostris>L. vannamei>F. californiensis=X. kroyeri and exoskeleton F. brevirostris>F. californiensis>L. vannamei>L. stylirostris>X. kroyeri.

Analysis of Variance↗

PubMed2005

Cleaner shrimp use a rocking dance to advertise cleaning service to clients.

Signals transmit information to receivers about sender attributes, increase the fitness of both parties, and are selected for in cooperative interactions between species to reduce conflict [1, 2]. Marine cleaning interactions are known for stereotyped behaviors [3-6] that likely serve as signals. For example, "dancing" and "tactile dancing" in cleaner fish may serve to advertise cleaning services to client fish [7] and manipulate client behavior [8], respectively. Cleaner shrimp clean fish [9], yet are cryptic in comparison to cleaner fish. Signals, therefore, are likely essential for cleaner shrimp to attract clients. Here, we show that the yellow-beaked cleaner shrimp [10] Urocaridella sp. c [11] uses a stereotypical side-to-side movement, or "rocking dance," while approaching potential client fish in the water column. This dance was followed by a cleaning interaction with the client 100% of the time. Hungry cleaner shrimp, which are more willing to clean than satiated ones [12], spent more time rocking and in closer proximity to clients Cephalopholis cyanostigma than satiated ones, and when given a choice, clients preferred hungry, rocking shrimp. The rocking dance therefore influenced client behavior and, thus, appears to function as a signal to advertise the presence of cleaner shrimp to potential clients.

Analysis of Variance↗

PubMed2004

Evaluation of Pseudomonas sp. PM 11 and Vibrio fluvialis PM 17 on immune indices of tiger shrimp, Penaeus monodon.

Occurrence of widespread epizootics among cultured stock of shrimp has put research programmes on preventive approaches such as application of probiotics on a high priority in aquaculture. In the present study two bacteria, Pseudomonas sp. PM 11 and Vibrio fluvialis PM 17 were selected as candidate probionts from a pool of bacteria isolated from gut of farm reared sub-adult shrimp and tested for their effect on the immunity indicators of tiger shrimp. Sub-adult shrimp, weighing 14 to 22 g were treated in separate experiments with Pseudomonas sp. PM 11 and V. fluvialis PM 17 at 10(3) bacterial cells ml(-1) in the experimental shrimp culture tanks. One set of experimental animals was treated every 3 days and another set of animals every 7 days with each of the candidate probionts. Estimation of immunological indicators such as haemocyte counts, phenol oxidase and antibacterial activity showed declining trends. The haemocyte counts dropped from 31 x 10(3) to 65 x 10(3) ml(-1) on the first day to 4-16 x 10(3) ml(-1) on the 45th day. Similarly, the phenol oxidase activity declined from 12-32 units on the first day to 11-14 units on 45th day of the experiment. Antibacterial activity of haemolymph reduced to 46-67 percent on the 45th day of the experiment. The results of the study suggest that, the criteria used for the selection of putative probiotic strains in the present study, such as predominant growth on primary isolation media, ability to produce extracellular enzymes and siderophores, did not bring about the desired effect in vivo and improve the immune system in shrimp. Hence, new protocols have to be evolved for selection of microbe(s) as putative probiotics and that, detailed understanding of proven probiotics, employed presently on empirical basis may provide a clue on the selection procedure.

Animals↗

PubMed2005

Dietary administration of sodium alginate enhances the immune ability of white shrimp Litopenaeus vannamei and its resistance against Vibrio alginolyticus.

Haemocyte count, phenoloxidase activity, respiratory burst (release of superoxide anion), superoxide dismutase (SOD) activity, glutathione peroxidase (GPX) activity, phagocytic activity and clearance efficiency to the pathogen Vibrio alginolyticus were measured in white shrimp Litopenaeus vannamei juveniles (12.3 +/- 1.2 g) which had been fed diets containing sodium alginate at 0.5, 1.0, 2.0 g kg(-1) after five months. L. vannamei fed a diet containing 2.0 g kg(-1) sodium alginate had increased phenoloxidase activity, respiratory burst and SOD activity, but decreased GPX activity significantly. L. vannamei fed a diet containing 2.0 g kg(-1) sodium alginate had increased phagocytic activity and the shrimp fed a diet containing sodium alginate at 0.5, 1.0 or 2.0 g kg(-1) had increased clearance efficiency to V. alginolyticus. In another experiment, L. vannamei, which had been fed control diet, or sodium alginate-containing diets after 5 months, were challenged with V. alginolyticus at 2 x 10(6) colony-forming units (CFU) shrimp(-1) and then placed in seawater of 15 per thousand. The survival of shrimp fed a diet containing 2.0 g kg(-1) after one day, and the survival of shrimp fed diets containing sodium alginate at 0.5 and 1.0 g kg(-1) after 2-4 days increased significantly, as compared to that of shrimp fed control diet. It is therefore concluded that administration of sodium alginate in the diet at 2.0 g kg(-1) or less could enhance the immune ability of L. vannamei and increase its resistance to V. alginolyticus infection.

Alginates↗

PubMed2006

The effect of sodium alginate on the immune response of tiger shrimp via dietary administration: activity and gene transcription.

The total haemocyte count (THC), phenoloxidase (PO) activity, respiratory bursts (release of superoxide anions), and superoxide dismutase (SOD) activity, as well as expressions of beta-1,3-glucan-binding protein (betaGBP), prophenoloxidase (proPO), peroxinectin (PE), cytosolic SOD (cyt-SOD), penaeidin-5 (PA-5), and a single whey acidic protein (WAP) domain protein (SWDP) gene were determined in the tiger shrimp Penaeus monodon (15.6-19.5g) which had individually been fed diets containing sodium alginate at 0, 1.0, or 2.0gkg(-1) for 5months. Results showed that shrimp fed a diet containing 1.0 and 2.0gkg(-1) sodium alginate had significantly increased SOD activity but decreased respiratory bursts. The expressions of betaGBP, PE, cyt-SOD, PA-5, and SWDP were significantly elevated in shrimp fed the <or=2.0gkg(-1) sodium alginate-containing diet for 5months. However, no significant differences in THC, PO activity, or proPO mRNA transcription in shrimp were observed among the three treatments. It was concluded that sodium alginate can be used as an immunomodulator for shrimp through dietary administration to modify immune genes expression of shrimp.

Alginates↗

PubMed2006

Dietary transfer of fluoranthene from an estuarine oligochaete (Monopylephorus rubroniveus) to grass shrimp (Palaemonetes pugio): Influence of piperonyl butoxide.

The objective of this study was to determine the potential for dietary transfer of sediment-associated fluoranthene from tubificid oligochaetes (Monopylephorus rubroniveus) to grass shrimp (Palaemonetes pugio). Grass shrimp, either in the presence or absence of sublethal waterborne concentrations of the metabolic inhibitor, piperonyl butoxide (PBO), were fed fluoranthene-dosed oligochaetes for 5-days. All grass shrimp bioaccumulated fluoranthene; however, bioaccumulation was 3X higher in the presence of PBO. Trophic transfer coefficients (TTCs) were 0.02 and 0.01 in the presence and absence of PBO, respectively. Following the 5-day accumulation period, shrimp in both treatments were allowed to depurate for 3 days. Depuration rates were significantly higher in PBO-exposed shrimp. These results demonstrated that sediment-associated fluoranthene can be transferred through the diet from oligochaetes to grass shrimp, and the presence of PBO enhanced fluoranthene bioaccumulation. However, the comparatively low TTCs suggest that biomagnification of fluoranthene in estuarine food webs is low.

Animals↗

PubMed2004

Water and sediment quality, partial mass budget and effluent N loading in coastal brackishwater shrimp farms in Bangladesh.

The present study aimed to quantify the water and sediment quality and growth and production parameters and to establish nutrient budgets for an average of five selected semi-intensive shrimp ponds in Bangladesh over a growing cycle. Physico-chemical parameters of water and sediments were measured and analyzed by standard methods. Gross yield (kg ha-1) of shrimp was calculated from the stocking and harvesting data. Finally, a partial nutrient mass budget for N and P was calculated. Most of the parameters of water and sediments correlated significantly with each other suggesting a high degree of interactions between different parameters in the system. Significantly higher concentrations of all species of nitrogenous nutrients were recorded in the effluent waters than that entering into the ponds. Therefore, a high loading and net output of nitrogenous nutrients in effluent waters was documented. The study also indicated a net discharge of solids and minerals through effluent loading. However, significantly lower concentrations of phosphorus in the effluent water indicated a net retention and trapping of phosphatic nutrients in the environment. Total production ranged between 532.0 and 697.0 kg ha-1 cycle-1 and P. monodon production between 484.0 and 562.0 kg ha-1 cycle-1. Ponds gained nitrogen primarily from intake water (55%) and fertilizers (29%), and nitrogen was lost primarily from water exchange (78%) and harvested shrimp (12%). Phosphorus gain occurred mostly from intake water (52%) and fertilizers (25%), and phosphorus was lost primarily from water exchange (52%) and harvested shrimp (3.3%). About 10% of input nitrogen and 44% of phosphorus were not accounted for in measured losses, and presumably were fixed or metabolized in the system. On average, 78 g N was discharged to and 25 g P was removed from the surrounding water by the system for each kilogram of shrimp produced. Mean conversion of feed nitrogen and phosphorus to shrimp flesh averaged 74% and 40%, respectively. It was concluded that semi-intensive systems serve as net supplier of N to and net remover of P from the surrounding water.

Animals↗

PubMed2005

Molecular cloning and characterization of Fc-TSP from the Chinese shrimp Fennerpenaeus chinensis.

Thrombospondins (TSPs) are extracellular, multidomain, calcium-binding glycoproteins that modulate cell behavior in homeostasis and during development, wound-healing, immune response and tumor growth of adult tissues in vertebrates. In invertebrates these proteins are a major component of cortical rods in mature oocytes. A fragment of a thrombospondin-like gene was generated by screening a subtractive cDNA library constructed from the hemocytes of Chinese shrimp, Fennerpenaeus chinensis. The full length F. chinensis cDNA of thrombospondin was cloned by 3'- and 5'-rapid amplification of cDNA ends (3'- and 5'-RACE). The complete cDNA sequence, named Fc-TSP, is 2886 bp and the open reading frame of the cDNA encodes a 938-residue protein that contains three ChtBD2 domains, an EGF domain, a TSP-3 domain and a common TSP-C (CTD) domain. The protein shares a high sequence identity with the mj-TSPa (46.3%), mj-TSPb (46.9%) and mj-TSPc (51.9%) of Marsupenaeus japonicus. The expression and distribution of Fc-TSP in both challenged and unchallenged shrimps were studied by Northern blot, RT-PCR and in situ hybridization. Northern blot analysis showed that the Fc-TSP transcripts were detected in the hemocytes, heart, intestine, stomach and ovary of both challenged and unchallenged shrimps, but the signal was much stronger in the challenged tissues. A strong hybridization signal was detected only in challenged hepatopancreas, with no signal in the unchallenged tissue. The RT-PCR showed that the Fc-TSP was detected in both challenged and unchallenged tissues including the hemocytes, heart, hepatopancreas, stomach, gills, intestine, spermary and ovary. Except for the ovary and spermary, the signal of challenged tissues was relatively stronger than that of unchallenged ones, especially in hepatopancreas. These results suggest that the thrombospondin was upregulated in the hemocytes, heart, intestine and stomach of challenged shrimp, and induced in the hepatopancreas of challenged shrimps. Therefore, Fc-TSP may be involved in the defense responses of the shrimp.

Amino Acid Sequence↗

PubMed2006

Effects of coal combustion residues on survival, antioxidant potential, and genotoxicity resulting from full-lifecycle exposure of grass shrimp (Palaemonetes pugio Holthius).

Coal combustion residues (CCRs), largely derived from coal-fired electrical generation, are rich in numerous trace elements that have the potential to induce sublethal effects including oxidative stress, alterations in antioxidant status and DNA single strand breaks (SSB). CCRs are frequently discharged into natural and man-made aquatic systems. As the effects of CCRs have received relatively little attention in estuarine systems, the estuarine grass shrimp, Palaemonetes pugio, was chosen for this study. Grass shrimp were exposed in the laboratory to CCR-enriched sediments and food over a full life cycle. Survival to metamorphosis was significantly reduced in CCR-exposed larvae (17+/-4 versus 70+/-13% in the controls) but not in the juveniles or adults. The COMET assay, a general but sensitive assay for genotoxicity, was used to quantify DNA SSB in the adults. Total antioxidant potential was examined to assess the overall antioxidant scavenging capacity of CCR-exposed and non-exposed adult grass shrimp. Grass shrimp exposed to CCR significantly accumulated selenium and cadmium compared to unexposed shrimp, although an inverse relationship was seen for mercury accumulation. Chronic CCR exposure caused DNA SSB in hepatopancreas cells, as evidenced by the significantly increased percent tail DNA, tail moment, and tail length as compared to reference shrimp. However, no significant difference was observed in total antioxidant potential. Our findings suggest that genotoxicity may be an important mode of toxicity of CCR, and that DNA SSB may serve as a useful biomarker of exposure and effect of this very common, complex waste stream.

Animals↗

PubMed2005

Tissue distributions and seasonal dynamics of the hepatotoxic microcystins-LR and -RR in two freshwater shrimps, Palaemon modestus and Macrobrachium nipponensis, from a large shallow, eutrophic lake of the subtropical China.

So far no information is available on microcystin (MC) contents in shrimps, prawns or crayfish from natural freshwaters. Tissue distributions and seasonal dynamics of the hepatotoxic MC-LR and -RR in two freshwater shrimps, Palaemon modestus and Macrobrachium nipponensis were studied monthly (during June-November, 2003) in a Chinese lake containing toxic cyanobacterial blooms. The shrimps P. modestus and M. nipponensis accumulated high MCs not only in the hepatopancreas (mean 4.29 and 0.53 microg g(-1) DW, respectively) but also in the gonad (mean 1.17 and 0.48 microg g(-1) DW, respectively), and the crayfish Procambarus clarkii accumulated as much as 0.93 microg g(-1) DW in the gonad. This indicates that gonads of these invertebrates are the second important target organ of MCs. P. modestus apparently accumulated more MCs in their organs than M. nipponensis, which might be a reflection of their difference in trophic niche. Eggs of the shrimps accumulated 8.4% (M. nipponensis, 0.27 microg g(-1) DW) and 29.0% (P. modestus, 2.34 microg g(-1) DW) of total toxin burden, indicating that MCs had been transferred into offspring from their adults. Among the shrimp muscle samples analyzed, 31% were above the provisional WHO TDI level, suggesting the risk of consuming shrimps in Lake Chaohu.

Animals↗

PubMed2005

A new RNA virus found in black tiger shrimp Penaeus monodon from Thailand.

A new, apparently innocuous virus was found while investigating the cause of monodon slow growth syndrome (MSGS) in cultured black tiger shrimp (Penaeus monodon). It was identified via plasmid vector clones of E. coli containing randomly amplified cDNA fragments produced from total nucleic acid extracts of hemolymph from MSGS shrimp. Of 421 clones, 30 that failed to give positive dot blot hybridization with a digoxigenin (DIG)-labeled shrimp DNA probe were sequenced and compared to GenBank records. Of these, 22 corresponded to known shrimp DNA records. Of eight that did not, one (20A) showed significant deduced amino acid sequence similarity to RNA-dependent RNA polymerases (RdRp) of the viruses in the family Luteoviridae and alignment revealed commonly conserved amino acids including a GDD motif believed to be at the enzyme active site. However, phylogenetic analysis showed that the virus sequence did not cluster with the Luteoviridae or other known RNA virus sequences. Thus, in accordance with frequent practice, it was named according to the area where it was first collected as Laem-Singh virus (LSNV). In situ hybridization with a DIG-labeled 20A insert revealed strong cytoplasmic staining confined to the lymphoid organ (LO), the heart and hepatopancreatic connective tissue in both normal and MSGS shrimp. RT-PCR assays based on the 20A clone sequence also gave positive results with both normal and MSGS shrimp. Transmission electron microscopy (TEM) of LO tissue revealed viral-like particles of approximately 27 nm diameter (within the Luteoviridae size range) in locations that matched those of positive in situ hybridization reactions in parallel samples. Although not directly associated with MSGS in Penaeus monodon, the presence or effect of this virus with other crustacean species is presently unknown.

Amino Acid Sequence↗

PubMed2006

Comparison of the acute toxicity for gamma-cyhalothrin and lambda-cyhalothrin to zebra fish and shrimp.

Gamma-cyhalothrin 15CS (GCH) contains only the active stereoisomer of the two isomers found in lambda-cyhalothrin 25EW (LCH). GCH (0.5 x rate) provides equivalent overall insect control as LCH (1 x rate). Both formulations showed high acute toxicity to zebra fish (Brachydanio rerio H.B.) and shrimp (Macrobrachium nippoensis de Haan). The 96-h LC(50(zebra fish,GCH)) is 1.93 microg a.i/L and LC(50(zebra fish,LCH)) is 1.94 microg a.i/L. LC(50(shrimp,GCH)) is 0.28 microg a.i./L and LC(50(shrimp,LCH)) 0.04 microg a.i./L. This indicates that the toxicity to shrimp is likely stereochemistry-dependent. The fates of GCH and LCH are similar in laboratory simulated rice paddy water and their concentrations decrease rapidly, with no GCH or LCH detected after 3 or 4 days. Both are toxic to shrimp in a simulated paddy irrigation reservoir even though treated return water is diluted 5 times. No shrimp fatality is shown in the GCH-treated paddy water after a 4-day holding period, and longer than 5 days is necessary to reach a zero fatality rate for LCH. This is compatible with the 7-day water holding period considered reasonable in agricultural practice.

Animals↗

PubMed2000

The sensitivity of grass shrimp, Palaemonetes pugio, embryos to organophosphate pesticide induced acetylcholinesterase inhibition.

Grass shrimp, Palaemonetes pugio, are common inhabitants of salt marshes along the Atlantic and Gulf coasts of North America. Grass shrimp embryos are brooded externally on the abdomen of adult females for about 2 weeks prior to hatching. In South Carolina, the spring spawning period for grass shrimp coincides with the period of peak pesticide application on crops grown along the South Carolina coast. Thus, grass shrimp of all developmental stages are at risk of exposure to pesticides present in nonpoint source agricultural runoff. Organophosphate (OP) insecticides are commonly applied agricultural chemicals which produce toxicity by inhibiting the nervous system enzyme, acetylcholinesterase (AChE). The purpose of this study was to examine the development of AChE activity in grass shrimp embryos and to assess their sensitivity to OP-induced AChE inhibition. Embryos were exposed for 24 h to either chlorpyrifos or malathion. All exposure concentrations were nominal and ranged from 0 to 2.00 µg l(-1) for chlorpyrifos and from 0 to 120.00 µg l(-1) for malathion. Quantifiable levels of AChE activity first appeared at Stage V of development and increased as embryonic development progressed. AChE inhibition by the OPs was assessed in Stage VI and Stage VII embryos. Both stages of embryos were more sensitive to chlorpyrifos than malathion. The 24-h Effective Concentration (EC(50)) values for chlorpyrifos were 0.49 µg l(-1) (95% C.I.=0.33-0.77 µg l(-1)) and 0.36 µg l(-1) (95% C.I.=0.33-0.38 µg l(-1)) for Stage VI and Stage VII embryos, respectively. In comparison, malathion 24-h EC(50) values were 55.53 µg l(-1) (95% C.I.=22.08-80.73 µg l(-1)) for Stage VI embryos and 29.93 µg l(-1) (95% C.I.=25.22-44.22 µg l(-1)) for Stage VII embryos. For both OPs, there were no significant differences in the EC(50) values calculated for Stage VI and Stage VII embryos; however, AChE inhibition was significantly (P</=0.05) greater in Stage VII embryos at the two highest exposure concentrations for each insecticide. A comparison of the results of these embryo tests with those found for adult and larval toxicity tests indicated that embryos were at least as sensitive to both the OPs as larval and adult grass shrimp. Embryo bioassays provide a number of important advantages over traditional laboratory toxicity tests including reduced laboratory space requirements, large numbers of embryos from a few ovigerous females, and small volumes of waste.

Journal Article↗

PubMed1997

Purification and comparison of beta-1,3-glucan binding protein from white shrimp (Penaeus vannamei).

A beta-glucan binding protein (BGBP) was identified in both white (Penaeus vannamei) and blue shrimp (P. stylirostris) plasma. White shrimp BGBP was purified by affinity chromatography using immobilized laminarin, and its molecular and biological properties were described. White shrimp BGBP is a monomeric protein with a molecular mass of 100 kDa, similar to those described for other crustacean BGBPs. White and blue shrimp BGBPs can be detected with antisera against crayfish BGBP and brown shrimp BGBP. Both amino acid composition and N-terminal sequence are markedly similar to brown shrimp (P. californiensis) and crayfish (Pacifastacus leniusculus) BGBP, indicating that this recognition protein is present in freshwater and marine crustaceans.

Agglutinins↗

PubMed1999

Molecular cloning and characterization of a hemolymph clottable protein from tiger shrimp (Penaeus monodon).

To investigate the coagulation system in crustacean decapoda, a homodimeric glycoprotein of 380 kDa was purified from the hemolymph of tiger shrimp (Penaeus monodon) by sequential DEAE anion exchange chromatography. The purified protein was coagulated by the shrimp hemocyte transglutaminase in the presence of Ca2+. The clottable protein contains 44% alpha helices and 26% beta sheets as determined by circular dichroism spectra. Its conformation is stable in buffer of pH 4-9. To solve its primary structure, partial sequences of the purified polypeptides from cyanogen bromide cleavage and endopeptidase digestion were also determined. A shrimp cDNA expression library was constructed. By combination with antibody screening, reverse transcriptase PCR using degenerate primers from determined amino acid sequences and cDNA library screening with digoxigenin-labeled DNA probes, the entire cDNA of 6124 bp was obtained. This cDNA encodes a protein of 1670 amino acids, including a 14-amino acid signal peptide. With four potential N-glycosylation sites, the clottable protein was found to contain 3.8% high-mannose glycan; and Man8GlcNAc and Man9GlcNAc were released upon endo-beta-N-acetylglucosaminidase hydrolysis. Upon conducting a protein sequence database survey, the shrimp clottable protein shows 36% identities to the crayfish clotting protein and lower similarities to members of insect vitellogenins, apolipoprotein B and mammalian von Willebrand factor. Notably, a region rich in Gln residues, a polyGln motif and five Ser-Lys-Thr-Ser repeats are present in the shrimp protein, suggesting this protein might be a transglutaminase substrate. Northern blot analysis revealed that the clottable protein is expressed in most of the shrimp tissues but not in the mature hemocytes.

Amino Acid Sequence↗

PubMedDate not supplied

4-Hexylresorcinol as inhibitor of shrimp melanosis: efficacy and residues studies; evaluation of possible toxic effect in a human intestinal in vitro model (Caco-2); preliminary safety assessment.

Studies were performed on the efficacy, residues and in vitro enterocyte toxicity of 4-hexylresorcinol (4-HR), which could be utilized as an inhibitor of shrimp melanosis (black spot). Mediterranean sea shrimp (Parapaeneus longirostris) were treated with solutions of 4-HR in sea-water, at three different concentrations, 25, 50 or 100 mg/kg of shrimp, to test its antioxidative property. As a comparison a group of shrimp was treated with sodium metabisulphite (1 g/kg), while another group was left untreated. 4-HR showed a marked ability to inhibit or slow down melanosis (black spot) in shrimp; the most effective concentration was 100 mg/kg within an optimum period of 7 days but with effects up to the tenth day. During the first 5 days, 4-HR residues in the edible part of the shrimp showed a fast decrease in all three groups, going from initial average values of 20 mg/kg at 0 time, to 0.9 in the group treated at 25 mg/kg; from 42 to 1.8 mg/kg in the group at 50 mg/kg and from 85 to 1.9 mg/kg in the group at 100 mg/kg. In vitro studies on enterocyte-like Caco-2 cells did not indicate any cytotoxic effect up to a concentration of 50 micrograms/ml. Moreover, no inhibition of protein synthesis was observed, which lends further support to the absence of significant damage to the intestinal mucosa induced by 4-HR. The available database on 4-HR pharmacology and toxicology is inadequate to determine even a provisional ADI. There is negative evidence of carcinogenesis and no significant untoward effects were observed in humans when it was used as an anthelmintic. However, it is not possible to determine a NOEL for non-genotoxic effects. 4-HR could become an interesting alternative to the use of sulphites to prevent black spot. However, a more complete database is needed to achieve a regulatory evaluation.

Animals↗

PubMed1991

Biological control of Culex mosquitoes (Diptera: Culicidae) by the tadpole shrimp, Triops longicaudatus (Notostraca: Triopsidae).

Laboratory oviposition choice tests and behavioral observations indicated that the activity of tadpole shrimp, Triops longicaudatus (LeConte), near the water surface deterred gravid Culex quinquefasciatus Say from ovipositing. In the cities of Oasis and Riverside, Calif., tadpole shrimp significantly reduced the abundance of immature mosquitoes (Cx. tarsalis Coquillett and Cx. quinquefasciatus) probably due to lowered oviposition rates, as well as tadpole shrimp predation. Generally, mosquito oviposition rates in field ponds with tadpole shrimp were lower than that of controls, except when tadpole shrimp were very young (4 d after flooding) or when their abundance had declined late in the flooding period. When analyzed by pond, tadpole shrimp size was correlated inversely with abundance; however, differences in size or abundance did not affect their capacity to reduce mosquito populations.

Animals↗