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PubMed1997

Optimization of the solubilization and renaturation of fish growth hormone produced by Escherichia coli.

Growth hormone (GH) enhances the growth rate of aquacultured fish and shellfish, but it is difficult to extract native GH from fish pituitary glands. However, fish recombinant GH (rGH) can be efficiently synthesized by Escherichia coli cells, although it exists in denatured form in inclusion bodies (IB). We studied the solubilization of IB and the renaturation of rGH to help facilitate the production of a large amount of biologically active rGH. A 100-ml sample of rGH-producing E. coli produced 73.43 +/- 5.47 mg IB (dry weight, n = 3) after 20 h induction by 1 mM isopropyl beta-o-thiogalactopyranoside. Interestingly, if the bacteria were induced by 0.1 mM beta-lactose, 95.3 +/- 3.43 mg of IB was obtained. The optimal conditions for denaturation and renaturation of rGH were when IB were solubilized in 6 M guanidine hydrochloride and then dialysed against pH 10 dialysis buffer (50 mM ammonium bicarbonate and 2 mM EDTA) containing 100 mM L-arginine, 2 mM oxidized glutathione and 2 mM reduced glutathione for 24 h at 4 degrees C in a volume ratio of 3 to 500. At least 20% of the denaturated rGH in IB was renatured. Juvenile black sea bream injected with 0.05 microgram/g resultant rGH once every 2 weeks exhibited significant increases (P < 0.05) in weight gain (84%) relative to fish in the control group over a 16-week period. This process is an economical and effective way to obtain an active form of rGH biosynthesized by a prokaryotic system.

Animals↗

PubMed2002

Calculating resource restoration for an oil discharge in Lake Barre, Louisiana, USA.

Under the United States Oil Pollution Act of 1990, natural resource trustees are charged with assessing natural resource impacts due to an oil spill and determining the type and amount of natural resource restoration that will compensate the public for the impacts. Habitat equivalency analysis is a technique through which the impacts due to the spill and the benefits of restoration are quantified; both are quantified as habitat resources and associated ecological services. The goal of the analysis is to determine the amount of restoration such that the services lost are offset by services provided by restoration. In this paper, we first describe the habitat equivalency analysis framework. We then present an oil spill case from coastal Louisiana, USA, where the framework was applied to quantify resource impacts and determine the scale of restoration. In the Louisiana case, the trustees assessed impacts for oiled salt marsh and direct mortality to finfish, shellfish, and birds. The restoration project required planting salt-marsh vegetation in dredge material that was deposited on a barrier island. Using the habitat equivalency analysis framework, it was determined that 7.5 ha of the dredge platform should be planted as salt marsh. The planted hectares will benefit another 15.9 ha through vegetative spreading resulting in a total of 23.4 ha that will be enhanced or restored as compensation for the natural resource impacts.

Animals↗

PubMed1999

Hydrological and Oceanographic Considerations for Integrated Coastal Zone Management in Southern Belize.

/ The objectives of this study are to: (1) characterize the meteorology and hydrology of the Maya Mountain-Marine Area Transect in southern Belize, (2) employ a simple water balance model to examine the discharge rates of seven watersheds to Port Honduras, (3) test the validity of the hydrological model, (4) explore the implications of potential landscape and hydrological alterations, and (5) examine the value of protected areas. The southern coastal portion of the study area is classified as wet tropical forest and the remainder as moist tropical forest. Rainfall is 3000-4000 mm annually. Resulting annual freshwater discharge directly into Port Honduras is calculated at 2.5 x 10(9) m3, a volume equal to the basin. During the rainy season, June-September, 84% of the annual discharge occurs, which causes the bay to become brackish. Port Honduras serves as an important nursery ground for many species of commercially important fish and shellfish. The removal of forest cover in the uplands, as a result of agriculture, aquaculture, and village development, is likely to significantly accelerate erosion. Increased erosion would reduce soil fertility in the uplands and negatively affect mangrove, seagrass, and coral reef productivity in the receiving coastal embayment. Alternatively, the conservation of an existing protected areas corridor, linking the Maya Mountains to the Caribbean Sea, is likely to enhance regional sustainable economic development. This study aims to support environmental management at the scale of the "ecoscape"-a sensible ecological unit of linked watersheds and coastal and marine environments.KEY WORDS: Ecosystem management; Coastal zone management; Belize; Hydrologyhttp://link.springer-ny.com/link/service/journals/00267/bibs/24n2p229.html

Journal Article↗

PubMed2006

ATP-binding cassette, subfamily G (ABCG family).

This review summarizes the characteristics of the ATP-binding cassette, subfamily G (ABCG family), which has five members: ABCG1, ABCG2, ABCG4, ABCG5, and ABCG8. The members consist of a single ABC cassette in the amino terminal followed by six putative transmembrane domains, and to become functionally active, they form homo- or obligate heterodimers. Except for ABCG2, the members of the ABCG family play an important role in efflux transport of cholesterol. Mutations causing a loss of function of ABCG5 or ABCG8 are associated with sitosterolemia characterized by accumulation of phyto- and shellfish sterols. Unlike other members, ABCG2 is not involved in cholesterol efflux, but it exhibits broad substrate specificity to xenobiotic compounds. ABCG2 confers cancer cells resistance to anticancer drugs and plays a critical role in the pharmacokinetics of drugs in the clearance organs and tissue barriers. ABCG2 is also associated with a subpopulation phenotype of stem cells. Genetic polymorphisms of ABCG2 have been suggested to account for the interindividual differences in the pharmacokinetics of drugs.

ATP Binding Cassette Transporter, Subfamily G↗

PubMed2002

Temporal variability of Cryptosporidium in the Chesapeake Bay.

Although Cryptosporidium has been found worldwide in molluscan shellfish from waters contaminated with human and animal feces, little or no related environmental data have been obtained. In the present study, oysters ( Crassostrea virginica) were collected eight times over 3 years from seven sites in the Chesapeake Bay or its tributaries, with accompanying data on water temperature, salinity, rainfall, and streamflow. Oyster gill washings were examined by immunofluorescence microscopy for Cryptosporidium oocysts. Of 1,590 oysters collected, 19.6% had detectable oocysts. Of 53 collections, oocysts were detected 81% of the time. The time when the greatest percentage of oysters at most sites had detectable oocysts coincided with the time of greatest weekly and monthly rainfall, greatest streamflow into the Bay, and lowest water temperatures. In 28% of 53 collections, C. parvum genotypes 1 and 2 and C. baileyi were identified by PCR and gene sequencing. Oocyst infectivity was confirmed from 37.5% of 40 collections by initiating C. parvum genotype 2 infections in mice.

Animals↗

PubMed2001

Cryptosporidium parvum oocysts in zebra mussels (Dreissena polymorpha): evidence from the St Lawrence River.

Molluscan shellfish can recover and concentrate environmentally derived waterborne pathogens and can be used for the sanitary assessment of water quality. Oocysts of Cryptosporidium parvum (genotype 1) were identified in zebra mussels (Dreissena polymorpha) from the St. Lawrence River, Quebec. Approximately 67 oocysts/ml of hemolymph and 129 oocysts/g of soft tissue were recovered. The adjusted concentration of oocysts per gram of tissue was 2.2 x 10(2), and approximately 4.4 x 10(2) oocysts were recovered from a single mussel. Zebra mussels can serve as biological indicators of waterborne contamination with Cryptosporidium.

Animals↗

PubMed1999

Cryptosporidium oocysts in Bent mussels (Ischadium recurvum) in the Chesapeake Bay.

Filter-feeding molluscan shellfish can concentrate environmentally derived waterborne pathogens of humans, which can be utilized in the sanitary assessment of water quality. In the present study, oocysts of Cryptosporidium were detected in Bent mussels (Ischadium recurvum) at two Chesapeake Bay sites from which C. parvum-contaminated oysters had previously been collected. Spiking of Cryptosporidium-free blue mussel (Mytilus edulis) tissue with C. parvum oocysts showed a 51.1% recovery rate of oocysts, giving an oocyst detection limit of 19 oocysts/0.7 ml of mussel tissue homogenate. The results indicate that Bent mussels, which are common throughout the Chesapeake Bay region, may prove to be useful as biological indicators of water contamination with Cryptosporidium oocysts.

Animals↗

PubMed2003

Herman Jan Phaff: professor, mentor, friend and colleague.

Herman Jan Phaff, the father of yeast ecology, was born in the Netherlands in 1913. In his early years, he spent much time in his family's winery, which sparked his interest in microbes. Trained in the famous Delft tradition, Phaff discovered many unrecognized ecological niches of yeast, such as shellfish, rabbit stomach, frass of bark beetles, tree exudates, cactus roots, Capri figs, sewage, Drosophila flies and shrimp. He is also remembered for his pioneering work on the coevolution of yeasts, insects and plants as well as for his work on yeast beta-glucanase, which resulted in major advances in the understanding of the nature of the yeast cell wall. Phaff's legacy includes research on pectin degradation by fungal enzymes and the application of molecular approaches to yeast systematics. He discovered and described many yeasts, such as the yeast named in his honor, Phaffia rhodozyma, which led to the establishment of a very important industrial fermentation process yielding high concentrations of the pigment astaxanthin, used throughout the world to provide a natural source of this important carotenoid.

History, 20th Century↗

PubMedDate not supplied

Seafood allergy and allergens: a review.

Seafoods are composed of diverse sea organisms and humans are allergic to many of them. Tropomyosin is a major allergen in many shellfish, especially crustacea and mollusks. Interestingly, tropomyosin has also been identified as an important allergen in other invertebrates including dust mites and cockroaches, and it has been proposed by some to be an invertebrate pan allergen. Different regions of shrimp tropomyosin bind IgE; 5 major IgE-binding regions have been identified in shrimp tropomyosin containing 8 epitopes. Mutations of these shrimp allergenic epitopes can reduce seafood allergenicity; methods utilizing such mutations will provide safer vaccines for more effective treatment of seafood-allergic patients, and in the future less-allergenic seafood products for consumption.

Allergens↗

PubMed2005

Development of molecular probes for dinophysis (dinophyceae) plastid: a tool to predict blooming and explore plastid origin.

Dinophysis are species of dinoflagellates that cause diarrhetic shellfish poisoning. We have previously reported that they probably acquire plastids from cryptophytes in the environment, after which they bloom. Thus monitoring the intracellular plastid density in Dinophysis and the source cryptophytes occurring in the field should allow prediction of Dinophysis blooming. In this study the nucleotide sequences of the plastid-encoded small subunit ribosomal RNA gene and rbcL (encoding the large subunit of RuBisCO) from Dinophysis spp. were compared with those of cryptophytes, and genetic probes specific for the Dinophysis plastid were designed. Fluorescent in situ hybridization (FISH) showed that the probes bound specifically to Dinophysis plastids. Also, FISH on collected nanoplankton showed the presence of probe-hybridized eukaryotes, possibly cryptophytes with plastids identical to those of Dinophysis. These probes are useful not only as markers for plastid density and activity of Dinophysis, but also as tools for monitoring cryptophytes that may be sources of Dinophysis plastids.

Animals↗

PubMed2005

Species-specific detection and quantification of toxic marine dinoflagellates Alexandrium tamarense and A. catenella by Real-time PCR assay.

A Real-time polymerase chain reaction (PCR) assay was designed and evaluated for rapid detection and quantification of the toxic dinoflagellates Alexandrium catenella and A. tamarense, which cause paralytic shellfish poisoning. Two sets of PCR primers and fluorogenic probes targeting these two species were derived from the sequence of 28S ribosomal DNA. PCR specificity was examined in closely related Alexandrium spp. and many other microalgae. A. catenella-specific primers and probe detected the PCR amplification only from A. catenella strains, and nonspecific signals were not detected from any microalgae. Also, A. tamarense-specific primers and probe also detected the targeted species, suggesting the strict species specificity of each PCR. This assay could detect one cell of each species, showing its high sensitivity. Moreover, using the developed standard curves, A. tamarense and A. catenella could be quantified in agreement with the quantification by optical microscopy. The performance characteristics of species specificity, sensitivity, and rapidity suggest that this method is applicable to the monitoring of the toxic A. tamarense and A. catenella.

Animals↗

PubMed2000

Tropomyosin Is the Major Mollusk Allergen: Reverse Transcriptase Polymerase Chain Reaction, Expression and IgE Reactivity.

The complementary DNAs encoding tropomyosins of the abalone Haliotis diversicolor, the scallop Chlamys nobilis, and the mussel Perna viridis were amplified by reverse transcriptase polymerase chain reaction and thereafter cloned in plasmid vectors for expression. Immunoblot analysis showed that recombinant proteins of abalone, scallop, and mussel tropomyosin were reactive to serum IgE antibodies from subjects allergic to shellfish but not to nonallergic controls. Nucleotide and amino acid sequences of abalone, scallop, and mussel tropomyosins are highly similar (mostly > 55%) to those of crustacean allergens identified as tropomyosins. Absorption experiments showed that recombinant tropomyosins from the 3 mollusks were able to remove serum IgE reactivity against the 38-kDa tropomyosin of the organisms. These results demonstrate that tropomyosin is the major allergen among various common edible mollusks. Yet a comparison between the amino acid sequences of putative epitopes in crustaceans and mollusks suggests that the epitopes in the two groups may be distinct. Parsimony analysis of the nucleotide sequences of tropomyosin from different mollusks suggests that the tropomyosin gene sequence is a useful tool for phylogenetic analysis of this group of animals.

Journal Article↗

PubMed2006

Pollutant effects on Pacific oyster, Crassostrea gigas (Thunberg), hemocytes: screening of 23 molecules using flow cytometry.

The shellfish industry is an important economic activity in France, occurring mostly in estuarine zones subject to pollution due to anthropogenic activities. The harmful effects of pollutants on species inhabiting these estuarine zones are not well known. Among marine species, bivalve mollusks--particularly Pacific oyster, Crassostrea gigas--may serve a model of interest. The species is sedentary and filter-feeding, which favors bioaccumulation of pollutants in their tissues. Oysters may be suitable for studies on disturbance by pollutants of physiological activities, among which defense mechanisms are poorly documented in bivalves. In this study, effects of pollutants on hemocyte functions were monitored in Pacific oyster, C. gigas. Hemocytes were exposed in vitro to selected pollutants. The strategy for investigating the effects of pollutants on hemocyte functions is based on several biomarkers, which is more relevant than that of published papers based on single-endpoint experiments. Pollutants belonging to the most important groups of xenobiotics (PAHs, PCBs, and pesticides) were selected and their effect on hemocyte activities was analyzed using flow cytometry. Twenty-three pollutants were tested and eight of them showed significant modulation of hemocyte activities. PAHs and PCB 77 induced a decrease of hemocyte activity after an incubation periods of 4 and 24 h at 200 micro mol/L. Three pesticides (2,4D, paraoxon, and chlorothalonil) modulated hemocyte activities. A mixture of eight pesticides also decreased phagocytotic activity. This study is one of the first to investigate the effects of so many pollutants on hemocyte functions at the same time and therefore allows a real comparison of different pollutant effects.

Animals↗

PubMed2006

Radionuclide concentrations in benthic invertebrates from Amchitka and Kiska Islands in the Aleutian Chain, Alaska.

Concentrations of 13 radionuclides (137Cs, 129I, 60Co, 152Eu, 90Sr, 99Tc, 241Am, 238Pu, 239,249Pu, 234U, 235U, 236U, 238U) were examined in seven species of invertebrates from Amchitka and Kiska Islands, in the Aleutian Chain of Alaska, using gamma spectroscopy, inductively coupled plasma mass spectroscopy, and alpha spectroscopy. Amchitka Island was the site of three underground nuclear test (1965-1971), and we tested the null hypotheses that there were no differences in radionuclide concentrations between Amchitka and the reference site (Kiska) and there were no differences among species. The only radionuclides where composite samples were above the Minimum Detectable Activity (MDA) were 137Cs, 241Am, 239,249Pu, 234U, 235U, 236U, and 238U. Green sea urchin (Strongylocentrotus polyacanthus), giant chiton (Cryptochiton stelleri), plate limpets (Tectura scutum) and giant Pacific octopus (Enteroctopus dofleini) were only tested for 137Cs; octopus was the only species with detectable levels of 137Cs (0.262 +/- 0.029 Bq/kg, wet weight). Only rock jingle (Pododesmus macroschisma), blue mussel (Mytilus trossulus) and horse mussel (Modiolus modiolus) were analyzed for the actinides. There were no interspecific differences in 241Am and 239,240Pu, and almost no samples above the MDA for 238Pu and 236U. Horse mussels had significantly higher concentrations of 234U (0.844 +/- 0.804 Bq/kg) and 238U (0.730 +/- 0.646) than the other species (both isotopes are naturally occurring). There were no differences in actinide concentrations between Amchitka and Kiska. In general, radionuclides in invertebrates from Amchitka were similar to those from uncontaminated sites in the Northern Hemisphere, and below those from the contaminated Irish Sea. There is a clear research need for authors to report the concentrations of radionuclides by species, rather than simply as 'shellfish', for comparative purposes in determining geographical patterns, understanding possible effects, and for estimating risk to humans from consuming different biota.

Alaska↗

PubMed1993

Are n-3 fatty acids essential nutrients for fetal and infant development?

Recent research indicates that n-3 fatty acids (FAs) are essential nutrients in early human development. In human infants, nonhuman primates, and animal models, the n-3 FA, docosahexaenoic acid (DHA, 22:6n-3) is highly concentrated in brain and retinal tissues and accumulates during late fetal and early neonatal life. Diets deficient in n-3 FAs are associated with reduced levels of DHA in erythrocytes and brain and retinal tissues and with abnormalities in retinal function that may be irreversible. The precursor of DHA, alpha-linolenic acid (LNA, 18:3n-3), may be an inadequate substitute for DHA because LNA may not be converted to DHA in sufficient amounts to meet an infant's needs. Premature infants lose DHA from their tissues unless they are fed human milk or formula supplemented with DHA. Fish and shellfish are the main food sources of DHA. Women who consume fish have more DHA in their breast milk than do those who do not eat seafood. Infant formulas contain only LNA as a source of n-3 FAs. Pregnant and nursing women should be encouraged to consume seafood on a regular basis during pregnancy and lactation to furnish DHA for their infants.

Animals↗

PubMed1990

Determination of the presence of ceramide aminoethylphosphonate and ceramide N-methylaminoethylphosphonate in marine animals by fast atom bombardment mass spectrometry.

Phosphonosphingolipids from 15 kinds of shellfish were analyzed by fast atom bombardment mass spectrometry to determine the contents of ceramide aminoethylphosphonate (CAEPn) and ceramide N-methylaminoethylphosphonate (CMAEPn). Two pairs of ions, at m/z 126 and 140 in the positive ion mode and at m/z 124 and 138 in the negative ion mode, were used to distinguish between aminoethylphosphonic acid and N-methylaminoethylphosphonic acid in CAEPn and CMAEPn. Interestingly, mollusca in the early stage of evolution have both CAEPn and CMAEPn, while most in the middle stage have only CMAEPn and those in the highest stage have only CAEPn.

Aminoethylphosphonic Acid↗

PubMed1977

Heavy metal complexation in polluted molluscs. I. Limpets (Patella vulgata and Patella intermedia).

The accumulation of cadmium, zinc and copper by the marine gastropod molluscs Patella vulgata and Patella intermedia has been studied by gel permeation chromatography of water-soluble extracts of environmentally contaminated shellfish. A major proportion of the water-soluble cadmium and copper in these molluscs is associated with a protein of molecular weight 10 800 daltons. Evidence is presented supporting the similarity of this protein with mammalian metallothionein. This protein contained only a small proportion of the zinc found in the samples.

Amino Acids↗

PubMed1978

Heavy metal complexation in polluted molluscs. III. Periwinkles (Littorina littorea), cockles (Cardium edule) and scallops (Chlamys opercularis).

The accumulation of cadmium, zinc and copper by environmentally contaminated periwinkles, cockles and scallops has been studied by gel permeation chromatography of water-soluble extracts of the shellfish. Three distinct low mol. wt. (less than 3000) zinc complexes were separated from periwinkle extracts. Copper and cadmium were present as a single low mol. wt. species which is apparently responsible for the elevated copper levels in Littorina littorea.

Animals↗