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An island in the stream: Australia's place in the cosmopolitan world of Indo-West Pacific freshwater shrimp (Decapoda: Atyidae: Caridina).

Mitochondrial DNA sequences were used to investigate phylogenetic and biogeographic relationships among Australian freshwater shrimp from the genus Caridina H. Milne Edwards, 1837 (Atyidae) and congeners from potential source populations throughout the Indo-West Pacific region. Numerous Australian taxa have close evolutionary relationships with non-Australian taxa from locations throughout the region, indicating a diverse origin of the Australian freshwater fauna. This implies many colonisations to or from Australia over a long period, and thus highlights the surprising adeptness of freshwater shrimp in dispersal across ocean barriers and the unity of much of the region's freshwater biota. Interestingly, a study on Australia's other main genus of atyid shrimp, Paratya Miers, 1882, inferred only a single colonisation. A number of potential species radiations within Australia were also identified. This agrees with patterns detected for a large number of Australian freshwater taxa, and so implies a vicariant explanation due to the development of colder, dryer climates during the late Miocene/early Pliocene.

Animals↗

Epibenthic amphipod abundance and predation efficiency of the pink shrimp Farfantepenaeus duorarum (Burkenroad, 1939) in habitats with different physical complexity in a tropical estuarine system.

Amphipod abundance and biomass were determined in soft-bottom substrates (SBS), monospecific Thalassia testudinum patches and T. testudinum with attached macroalgae (SAV) from Términos Lagoon. Amphipods were absent in SBS, and their density and biomass were higher in SAV (3351 individualsm(-2), 1718 mg AFDWm(-2)) than in T. testudinum (1220 indm(-2), 625 mg AFDWm(-2)). Although macroalgae and seagrasses are recognised as an alternative refuge against predation for amphipods, the high abundance of amphipods in SAV suggests that macroalgae represent a habitat that provides greater food availability. Pink shrimp Farfantepenaeus duorarum (Burkenroad, 1939) consumption rate (Mo) of epibenthic amphipods was experimentally evaluated. Mo intensifies as prey density increases and varied from 0.39 to 2.39 mg AFDWh(-1). Predation efficiency of F. duorarum on epibenthic amphipods was also evaluated in four artificial habitats with different physical complexity: soft-bottom substrates (SBS), small woody debris (SWD), seagrasses with densities of 300 and 1200 shootsm(-2) (S300 and S1200, respectively), macroalgae (MA), and at two prey densities (962 and 2406 indm(-2)). Amphipod consumption rate by F. duorarum varied from 1.20 to 2.07 indh(-1) in S1200 and MA, respectively. Habitat complexity had a significant effect on consumption rate, but prey density did not. Habitat physical complexity and predation efficiency maintained an inverse and a non-linear relationship. Presumably, the decrease in predation efficiency in association with the habitat complexity is due to the differential refuge value of these habitats. However, predation efficiency may also be influenced by either the microhabitat use by amphipods, the shrimp's dependence on seagrasses, or by differences in habitat value caused by the diel behavioural distribution pattern of amphipods and shrimp. Both field and experimental results highlight the importance of evaluating the relative value of tropical estuarine habitats through the study of the relationship between habitat physical complexity and predator-prey interactions. They also emphasise that inherent biological and ethological factors of the predator and prey involved, coupled to spatial and temporal variations in the habitat, should also be considered.

Journal Article↗

A synthesis of dominant ecological processes in intensive shrimp ponds and adjacent coastal environments in NE Australia.

One of the key environmental concerns about shrimp farming is the discharge of waters with high levels of nutrients and suspended solids into adjacent waterways. In this paper we synthesize the results of our multidisciplinary research linking ecological processes in intensive shrimp ponds with their downstream impacts in tidal, mangrove-lined creeks. The incorporation of process measurements and bioindicators, in addition to water quality measurements, improved our understanding of the effect of shrimp farm discharges on the ecological health of the receiving water bodies. Changes in water quality parameters were an oversimplification of the ecological effects of water discharges, and use of key measures including primary production rates, phytoplankton responses to nutrients, community shifts in zooplankton and delta15N ratios in marine plants have the potential to provide more integrated and robust measures. Ultimately, reduction in nutrient discharges is most likely to ensure the future sustainability of the industry.

Animals↗

Protease produced by Pseudomonas aeruginosa K-187 and its application in the deproteinization of shrimp and crab shell wastes.

In addition to chitinase/lysozyme, Pseudomonas aeruginosa K-187 also produced a protease useful for the deproteinization of shrimp and crab shell wastes. The optimal culture conditions for P. aeruginosa K-187 to attain the highest protease activity were investigated and discussed. The highest protease activity was as high as 21.2 U/ml, 10-fold that (2.2 U/ml) obtained prior to optimization. The protease of P. aeruginosa K-187, produced under the optimal culture conditions, was tested for crustacean waste deproteinization. The percent of protein removal for shrimp and crab shell powder (SCSP) after 7-day incubation was 72%, while that of natural shrimp shell (NSS) and acid-treated SCSP was 78% and 45%, respectively. In contrast, with the protease produced under pre-optimization conditions, the percent of protein removal for SCSP, NSS, and acid-treated SCSP was 48%, 55%, and 40%, respectively. For comparison, three other protease-producing microbes were tested for crustacean waste deproteinization. However, they were shown to be less efficient in deproteinization than P. aeruginosa K-187. The crude protease produced by P. aeruginosa K-187 can be covalently immobilized on a reversibly soluble polymeric support (hydroxypropyl methycellulose acetate succinate). The immobilized enzyme was soluble above pH 5.5 but insoluble below pH 4.5. Immobilization efficiency was 82%. The immobilized enzyme was stable between pH 6 and 9 and at temperatures below 60 degrees C. The optimum pH and temperature for the immobilized enzyme was pH 8 and 50 degrees C. The half-life of the immobilized enzyme was 12 days, longer than that of free protease (8 days). The utilization of the immobilized enzyme for the deproteinization of SCSP has resulted in a 67% protein removal. By contrast, SCSP protein removal by using free enzymes was 72%. The protease was further purified and characterized. The purification steps included ammonium sulfate precipitation, DEAE-Sepharose CL-6B ion-exchange chromatography, and Sephacryl S-200 gel-permeation chromatography. The enzyme had a molecular weight estimated to be 58.8 kDa by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme was active from pH 7 to 9 and its optimal pH was 8.

Journal Article↗

Concentrations of Cd, Zn and Cu in sediments and brown shrimp (Crangon crangon L.) from the Severn Estuary and Bristol Channel, UK.

Cd, Zn and Cu levels were determined in sediments and Crangon crangon from 9 sites in the Severn Estuary/Bristol Channel during winter 1999. Metal levels in both shrimp and sediments varied significantly between sites and were related to proximity of input and/or sediment type. In the upper Estuary, Cd levels in shrimp were 100x higher than other reported values whereas sediment Cd contamination was comparable. It is suggested that high Cd levels in shrimp are due to the high inputs and enhanced bioavailability of metal during winter.

Animals↗

Bacterial formyl peptide mediated chemotaxis and extracellular acidification in shrimp haemocytes.

The bacterial formyl peptide N-formylmethionine-leucine-phenylalanine (fMLP) is a potent chemoattractant for mammalian neutrophils. In this study, we demonstrated the binding of fluorescent dye-conjugated-fMLP to haemocytes of the penaeid shrimp Penaeus penicillatus (Alcock), through the use of flow cytometry. Fluorescence microscopy with rhodamine-fMLP suggested that fMLP receptors are present only in sub-populations of the haemocytes: granulocytes and the semi-granular cells. In addition, fMLP dose-dependently mediated chemotaxis in sub-populations of haemocytes. Microphysiometry experiments demonstrated rapid extracellular acidification upon addition of fMLP, which is in agreement with the observation in neutrophils. t-BOC, the specific fMLP receptor antagonist, was able to block the binding, chemotaxis and extracellular acidification induced by the peptide. The ability of shrimp haemocytes to migrate toward fMLP in vitro suggests that this mechanism may be important for the accumulation of these cells in infected tissues of the shrimps.

Animals↗

Expression of penaeidin antimicrobial peptides in early larval stages of the shrimp Penaeus vannamei.

Penaeidins are a family of antimicrobial peptides constitutively produced and stored in the hemocytes of penaeid shrimps. We have determined the expression and the localization of penaeidins in the first early larval stages (Nauplius V, Zoea I, II, III and Mysis II) and in post-larvae (1 and 8) of the shrimp Penaeus vannamei. Using in situ hybridization and immunohistochemical analyses, we localized penaeidin transcripts and peptides in a few hemocytes of larvae from Mysis II stage. However, RT-PCR analyses showed that penaeidin mRNAs are already present in the early stage of Nauplius V. In addition, penaeidin expression could not be detected in other cells than hemocytes. Our observations highlight the potential involvement of penaeidins during larval development and the ontogeny of immune system through hemocytes during this period of life, where shrimps are particularly susceptible to infectious diseases.

Animals↗

Development of an in vitro quantal assay in primary cell cultures for a non-occluded baculo-like virus of penaeid shrimp.

An in vitro quantal assay (TCID50) for a non-occluded baculo-like virus isolate from naturally infected Penaeus japonicus obtained from China and experimentally infected P. stylirostris was developed using primary shrimp lymphoid cell cultures in Primaria 24-well tissue culture plates. The virus caused cytopathogenic effect (CPE) in the cell cultures as early as 2 day post-infection (p.i.). Initially, the cells rounded up and finally detached from the culture vessel as the infection progressed. At the present time, there is no established quantitative in vitro cell culture protocol for the assay of this baculo-like virus which has been reported by our laboratory to be highly pathogenic for P. stylirostris and P. vannamei, the two species of penaeid shrimp commercially cultured in Hawaii and the Western hemisphere. This quantal assay thus provides a simple and convenient method for the detection and assay of infectious virus in cultured penaeid shrimp.

Animals↗

Enumeration of coliforms and Escherichia coli in frozen black tiger shrimp Penaeus monodon by conventional and rapid methods.

Conventional (most probable number, MPN) and rapid methods-including Chromocult coliform agar (CCA), Fluorocult(R) LMX broth (LMX), and Petrifilm Escherichia coli count plates (PEC) for enumeration of coliforms and E. coli in frozen black tiger shrimp from Thailand were compared in order to assess the possibility of using one of the rapid methods for routine analysis. Enumeration of coliforms and E. coli from 18 samples of regular frozen black tiger shrimp and 156 samples of frozen black tiger shrimp experimentally contaminated with coliforms or E. coli at concentrations of approximately 10, approximately 10(2), and approximately 10(3) CFU g(-1) revealed that at the level of approximately 10 CFU g(-1), coliform numbers ranked as LMX>CCA>MPN=PEC and E. coli as MPN=LMX=PEC=CCA. At the level of approximately 10(2) CFU g(-1), coliform numbers ranked as LMX>MPN=PEC=CCA and E. coli as MPN=LMX>PEC=CCA. At the level of 10(3) CFU g(-1), coliforms ranked as LMX>MPN=CCA>PEC and E. coli as MPN>LMX>CCA>PEC. Agreements with the conventional MPN method for coliforms were LMX 108%, PEC 87.2%, and CCA 91.2% and agreements for E. coli were LMX 101%, PEC 95.7%, and CCA 96.3%. Sensitivities (%) ranked LMX>MPN>CCA=PEC for coliforms and E. coli, whereas equal specificities (100%) of all methods for coliforms and E. coli were demonstrated. Rankings for the other parameters compared were: convenience, PEC>CCA=LMX>MPN; time to detection, MPN>LMX=PEC=CCA; expense, MPN=PEC>CCA>LMX; labor, MPN>LMX=CCA>PEC; accuracy for coliforms, PEC>CCA>MPN>LMX; and accuracy for E. coli, PEC=CCA>LMX>MPN.

Agar↗

Comparison of penaeid shrimp and insect parvoviruses suggests that viral transfers may occur between two distantly related arthropod groups.

The DNA and putative amino acid sequences of representative insect and shrimp parvoviruses (subfamily Densovirinae) were analyzed using computer programs. Shrimp viruses included hepatopancreatic parvovirus (HPV) of Penaeus monodon (HPVmon) and P. chinensis (HPVchin), spawner-isolated mortality virus from P. monodon (SMVmon) and infectious hypodermal and hematopoietic necrosis virus (IHHNV) from P. vannamei. Insect viruses included Aedes aegypti densovirus (AaeDNV), Aedes albopictus densovirus (AalDNV), Junonia coenia densovirus (JcDNV), Galleria mellonella densovirus (GmDNV), Bombyx mori densovirus 5 (BmDNV), Diatraea saccharalis densovirus (DsDNV) and Periplaneta fuliginosa densovirus (PfDNV). Virion size for all these viruses ranged between 18 and 30 nm diameter and ssDNA genome length was between 4 and 6 kb. Using BLAST or Clustal W with the sequence fragments available, no significant DNA homology was found except for 77% DNA identity between HPVmon and HPVchin. However, phylogenetic trees constructed by comparing DNA genome sequences for putative viral polypeptides, capsid proteins and nonstructural proteins placed the parvoviruses into two Clades: Clade 1 with SMVmon, PfDNV, DsDNV, GmDNV, JcDNV, and BmDNV; and Clade 2 with HPVmon, HPVchin, IHHNV, AalDNV and AaeDNV. The four shrimp parvoviruses fell into two different clades that grouped with different insect parvoviruses.

Aedes↗

A hyperglycemic peptide hormone from the Caribbean shrimp Penaeus (litopenaeus) schmitti.

From a crude extract of the sinus glands of the shrimp Penaeus (litopenaeus) schmitti a peptide with hyperglycemic activity in a homologous bioassay was isolated and characterized by a combination of automatic Edman degradation, enzymatic digestions, TLC of dansyl-amino acids, and mass spectrometry. Its M(r) is 8359.4 Da by MS, which coincides with the deduced sequence. Its N-terminus is free and its C-terminus is amidated. It has 6 Cys residues in conserved positions compared with other known CHHs. This is the first sinus gland hormone from an Atlantic Ocean shrimp characterized to date. It has a remarkable 90% sequence similarity to the Indo-Pacific shrimp P. (marsupenaeus) japonicus Pej-VII hyperglycemic hormone.

Amino Acid Sequence↗

Toxicity assessment of fumonisins using the brine shrimp (Artemia salina) bioassay.

The Fusarium mycotoxins fumonisin B(1) (FB(1)) (1) and B(2) (FB(2)) (2), their hydrolysed analogues HFB(1) (3) and HFB(2) (4) and the recently discovered fumonisin derivatives N-palmitoyl-HFB(1) (5) and N-carboxymethyl-FB(1) (6) were compared for their toxicity in a short term bioassay using brine shrimp (Artemia salina). The brine shrimp were hatched in artificial sea water and exposed to the fumonisins in microwell plates with a mortality endpoint after 48 hours. LC(50) values were calculated after Probit transformation of the resulting data. Of the substances tested, fumonisin B(1) emerged to be the most toxic whereas its N-carboxymethyl analogue was 100-fold less effective. The hydrolysed fumonisins showed a four- to sixfold reduced toxicity compared to FB(1). N-Palmitoyl-HFB(1) had a higher LC(50) value than its precursor HFB(1). The brine shrimp assay proved to be a convenient and rapid system for toxicity assessment of this group of mycotoxins.

Animals↗

Environmental regulation through trade: the case of shrimp.

The implications of a potential ban on shrimp imports by the US from countries that do not utilize the Turtle Excluder Device on commercial shrimp nets is explored in this paper. A Linear Expenditure System (LES) was used to determine the own-price elasticities of demand for shrimp imports. The system of estimated equations was then solved for quantity levels under assumptions made about the trade restrictions, resulting in a set of prices for those import levels. These estimated prices were then used to estimate the compensating variation impact of the trade restrictions. Findings suggest that the environmental regulation would have a negative impact on US consumers, but the magnitude of that effect depends on assumptions made regarding the distribution of US imports after the trade restriction is imposed.

Animals↗

Structural features and anticoagulant activities of a novel natural low molecular weight heparin from the shrimp Penaeus brasiliensis.

A natural low molecular weight heparin (8.5 kDa), with an anticoagulant activity of 95 IU/mg by the USP assay, was isolated from the shrimp Penaeus brasiliensis. The crustacean heparin was susceptible to both heparinase and heparitinase II from Flavobacterium heparinum forming tri- and di-sulfated disaccharides as the mammalian heparins. (13)C and (1)H NMR spectroscopy revealed that the shrimp heparin was enriched in both glucuronic and non-sulfated iduronic acid residues. The in vitro anticlotting activities in different steps of the coagulation cascade have shown that its anticoagulant action is mainly exerted through the inhibition of factor Xa and heparin cofactor II-mediated inhibition of thrombin. The shrimp heparin has also a potent in vivo antithrombotic activity comparable to the mammalian low molecular weight heparins.

Animals↗

The hemolymph clottable proteins of tiger shrimp, Penaeus monodon, and related species.

A clottable protein was purified from the hemolymph of tiger shrimp (Penaeus monodon) by sequential DEAE anion-exchange chromatography. The protein formed stable clots in the presence of Ca2+ and the transglutaminase in hemocyte lysate. It is thermostable at temperatures up to 66 degrees C. The molecular mass of the clottable protein was determined to be 380 kDa by SDS-PAGE and MALDI-TOF mass spectrometry, and the protein exists as disulfide-linked homodimers and oligomers. The size and amino acid composition of the clottable protein are similar to those of several other shrimps, prawns, lobster and crayfish, and their N-terminal amino acid sequences are 60-80% identical. Monosaccharide analysis of the clottable protein revealed the presence of mannose, glucosamine or N-acetylglucosamine and possibly glucose in this glycoprotein of about 5% sugar content. Lipid in the protein upon electrophoresis was hardly detectable with the Oil Red O staining method. In immunodiffusion and immunoblotting analyses, the anti-clottable protein antibodies reacted with the clottable proteins from the penaeid shrimps but not with those from other crustaceans.

Amino Acid Sequence↗

Differential expression of ras in organs and embryos of shrimp Penaeus monodon (Crustacea: Decapoda).

Total RNA from shrimp hepatopancreas of Penaeus monodon showed three prominent bands that react with the shrimp ras probe, a 239-bp product, of approximately 4.8 kb (R1), 3.1 kb (R2) and 1.3 kb (R3) on the northern blot. The R1 is the least abundant. Analyses of total RNA from gill and heart were similar to each other. The highest expression of Ras was observed in the gill, while a negligible signal was detected with the Ras probe in muscle. Ras expression is developmentally regulated in embryonic stages of shrimp. Messenger RNA levels of ras were increased from a minimum in the nauplius stage to a maximum in the post-larvae stage for R1 and R2. R3 showed a maximum at the protozoea stage. On the other hand, the activity of protein geranylgeranyltransferase I was increased significantly in the early nauplius stage. No correlative increase of prenylation activity by protein geranylgeranyltransferase I was observed with the transcription activity of ras.

Amino Acid Sequence↗

The shrimp FAMeT cDNA is encoded for a putative enzyme involved in the methylfarnesoate (MF) biosynthetic pathway and is temporally expressed in the eyestalk of different sexes.

Methylfarnesoate (MF), an analogue of the insect juvenile hormone III, has been implicated to play a vital role in the regulation of the growth and reproductive development in crustaceans. Farnesoic acid O-methyltransferase (FAMeT) is the key enzyme involved in catalyzing the final step in the MF biosynthetic pathway. In this study, we report the cloning and characterization of the cDNA encoding the putative FAMeT of the shrimp Metapenaeus ensis. FAMeT comprises 280 amino acid residues with a predicted molecular weight of 32kDa. The predicted putative FAMeT protein reveals a high degree of structural conservation of FAMeT with the lobsters. It shares 79 and 70% sequence identities with the putative FAMeTs of Homarus americanus and Panulirus interruptus, respectively. As revealed by the Southern blot analysis and genomic PCR, only one gene exists in the shrimp genome and the gene is uninterrupted in the coding region. The shrimp FAMeT mRNA is widely distributed in many tissues with the highest expression level observed in the central nervous system. A constant level of FAMeT expression is recorded in the ventral nerve cord of the juveniles and the mature females during the reproductive cycle. Unlike the ventral nerve cord, the eyestalk of the juvenile male, but not the female, expresses FAMeT. Further study shows that the eyestalk of the mature female expresses FAMeT during all stages of ovarian maturation. We speculate that FAMeT may be important for the regulation of eyestalk neuropeptides. This is the first extensive study on the molecular characterization, structural analysis and expression of the crustacean FAMeT.

Amino Acid Sequence↗

cDNA cloning of the lysozyme of the white shrimp Penaeus vannamei.

Lysozyme, an antibacterial protein, has been implicated in innate immunity in invertebrates, but its activity in shrimp remained to be determined. We cloned the white shrimp lysozyme cDNA using a PCR strategy and detected its activity in haemocytes using a lytic-zone assay against Micrococcus luteus. The cloning was based on a reported EST (dbEST BE18831). The deduced amino acid sequence resulted in 150 amino with 46% identity to hen egg white lysozyme. RT-PCR was used to detect lysozyme mRNA in haemocytes. Analysis of the amino acid sequence of the shrimp lysozyme showed that it belongs to the C-type family of lysozymes. Furthermore, the lysozyme amino acid sequence contained extra residues at its C-terminus, which are characteristic of marine invertebrates. This information will be useful in future studies on the molecular mechanisms of immunity in marine invertebrates.

Amino Acid Sequence↗