Identification of factors affecting the growth and survival of the settling Japanese flounder larvae, Paralichthys olivaceus

A series of experiments were conducted to identify the factors that affected the growth and survival of the settling flounder larvae Paralichthys olivaceus. Settling larvae 24 days after hatching (DAH) were reared in 10-l experimental tanks up to 40 DAH, and two of the following factors were changed as controlled factors in each experiment: light regime (24L:0D or 12L:12D), prey density (1500, 3000, or 5000 Artemia l(-1)), shelter (sand or no sand) and stocking density (5, 10, or 15 fish l(-1)). Early settling larvae (24-35 DAH) experienced little mortality (less than 10% of the overall mortality) that was not significantly affected by above factors. In contrast, late settling larvae (36-40 DAH) suffered high cannibalistic mortality which was significantly influenced by each of the above factors. Larvae experienced significantly lower mortality at 10 fish l(-1) level than at other densities. Larvae at 15 fish l(-1) level had higher mortality than at 5 fish l(-1) when all other factors were identical. Larvae at 3000 and 5000 Artemia l(-1) treatments survived significantly better than at 1500 Artemia l(-1), but no significant differences in larval mortality were found between the two higher densities. Larvae suffered higher mortality at low prey density or at the absence of sand when they were exposed to longer photoperiod. Low stocking density significantly improved the growth of the settling larvae. The average daily instantaneous growth rate (G) at 5 and 15 fish l(-1) treatments were 0.050 and 0.034, with the coefficient of variation (CV) in final length at 16.4 and 23.5, respectively. Daily instantaneous growth rate increased significantly from 0.033 in the 1500 Artemia l(-1) to 0.041 and 0.045 in the 3000 and 5000 Artennia l(-1), respectively, but no significant difference in larval growth existed between the two higher prey densities. These findings suggested that the optimal prey density for growth and survival of the settling flounder larvae at a stocking density of 5 - 15 fish l(-1) was around 3000 Artemia l(-1) . Larvae that were exposed to 24L showed 20% increase in growth ( G = 0.046, CV = 18.7) than those exposed to 12L ( G = 0.037, CV = 20.5). Longer exposure to light significantly improved larval growth, provided sufficient food was available. Sand substrate did not show significant effects on larval growth, possibly because the larvae spent most of the time swimming or feeding in the water column during this stage. (C) 2003 Elsevier Science B.V. All rights reserved.

Toxin-screening and identification of bacteria isolated from highly toxic marine gastropod Nassarius semiplicatus

Bacteria isolated from a highly toxic sample of gastropod Nassarius semiplicatus in Lianyungang, Jiangsu Province in July 2007, were studied to probe into the relationship between bacteria and toxicity of nassariid gastropod. The toxicity of the gastropod sample was 2 x 10(2) mouse unit (MU) Per gram Of tissue (wet weight). High concentration of tetrodotoxin (TTX) and its analogues (TTXs) were found in the digestive gland and muscle of the gastropod, using high performance liquid chromatography coupled with mass chromatography (LC-MS). Bacterial strains isolated from the digestive gland were cultured and screened for TTX with a competitive ELISA method. Tetrodotoxin was detected in a proportion of bacterial strains, but the toxin content was low. Partial 16S ribosomal DNA (rDNA) of the TTX-producing strains was then sequenced and compared with those published in the GenBank to tentatively identify the toxic strains. It was found that most of the toxic strains were closely affiliated with genus Vibrio, and the others were related to genus Shewanella, Marinomonas, Tenacibaculum and Aeromonas. These findings suggest that tetrodotoxin-producing bacteria might play an important role in tetrodotoxin accumulation/production in N. semiplicatus. (C) 2008 Elsevier Ltd. All rights reserved.

Identification of a silicatein(-related) protease in the giant spicules of the deep-sea hexactinellid Monorhaphis chuni

Silicateins, members of the cathepsin L family, are enzymes that have been shown to be involved in the biosynthesis/condensation of biosilica in spicules from Demospongiae (phylum Porifera), e. g. Tethya aurantium and Suberites domuncula. The class Hexactinellida also forms spicules from this inorganic material. This class of sponges includes species that form the largest biogenic silica structures on earth. The giant basal spicules from the hexactinellids Monorhaphis chuni and Monorhaphis intermedia can reach lengths of up to 3 m and diameters of 10 mm. The giant spicules as well as the tauactines consist of a biosilica shell that surrounds the axial canal, which harbours the axial filament, in regular concentric, lamellar layers, suggesting an appositional growth of the spicules. The lamellae contain 27 kDa proteins, which undergo post-translational modification (phosphorylation), while total spicule extracts contain additional 70 kDa proteins. The 27 kDa proteins cross-reacted with anti-silicatein antibodies. The extracts of spicules from the hexactinellid Monorhaphis displayed proteolytic activity like the silicateins from the demosponge S. domuncula. Since the proteolytic activity in spicule extracts from both classes of sponge could be sensitively inhibited by E-64 (a specific cysteine proteinase inhibitor), we used a labelled E-64 sample as a probe to identify the protein that bound to this inhibitor on a blot. The experiments revealed that the labelled E-64 selectively recognized the 27 kDa protein. Our data strongly suggest that silicatein(-related) molecules are also present in Hexactinellida. These new results are considered to also be of impact for applied biotechnological studies.

Identification of quantitative trait loci for growth-related traits in the Pacific abalone Haliotis discus hannai Ino

The locations and effects of quantitative trait loci (QTL) were estimated for nine characters for growth-related traits in the Pacific abalone (Haliotis discus hannai Ino) using a randomly amplified polymorphic DNA (RAPD), amplification fragment length polymorphism (AFLP) and SSR genetic linkage map. Twenty-eight putatively significant QTLs (LOD > 2.4) were detected for nine traits (shell length, shell width, total weight, shell weight, weight of soft part, muscle weight, gonad and digestive gland weight, mantle weight and gill weight). The percentage of phenotypic variation explained by a single QTL ranged from 8.0% to 35.9%. The significant correlations (P < 0.001) were found among all the growth-related traits, and Pearson's correlation coefficients were more than 0.81. For the female map, the QTL for growth were concentrated on groups 1 and 4 linkage maps. On the male map, the QTL that influenced growth-related traits gathered on the groups 1 and 9 linkage maps. Genetic linkage map construction and QTL analysis for growth-related traits are the basis for the marker-assisted selection and will eventually improve production and quality of the Pacific abalone.

Inheritance of 15 microsatellites in the Pacific oyster Crassostrea gigas: segregation and null allele identification for linkage analysis

Microsatellites were screened in a backcross family of the Pacific oyster, Crassostrea gigas. Fifteen microsatellite loci were distinguishable and polymorphic with 6 types of allele-combinations. Null alleles were detected in 46.7% of loci, accounting for 11.7% of the total alleles. Four loci did not segregate in Mendelian Ratios. Three linkage groups were identified among 7 of the 15 segregating loci. Fluorescence-based automated capillary electrophoresis (ABI 310 Genetic Analyzer) that used to detect the microsatellite loci, has been proved a fast, precise, and reliable method in microsatellite genotyping.

Identification and mapping of amplified fragment length polymorphism markers linked to shell color in bay scallop, Argopecten irradians irradians (Lamarck, 1819)

Amplified fragment length polymorphisms (AFLP) were used to study the inheritance of shell color in Argopecten irradians. Two scallops, one with orange and the other with white shells, were used as parents to produce four F-1 families by selfing and outcrossing. Eighty-eight progeny, 37 orange and 51 white, were randomly selected from one of the families for segregation and mapping analysis with AFLP and microsatellite markers. Twenty-five AFLP primer pairs were screened, yielding 1138 fragments, among which 148 (13.0%) were polymorphic in two parents and segregated in progeny. Six AFLP markers showed significant (P < 0.05) association with shell color. All six loci were mapped to one linkage group. One of the markers, F1f335, is completely linked to the gene for orange shell, which we designated as Orange1, without any recombination in the progeny we sampled. The marker was amplified in the orange parent and all orange progeny, but absent in the white parent and all the white progeny. The close linkage between F1f335 and Orange1 was validated using bulk segregation analysis in two natural populations, and all our data indicate that F1f335 is specific for the shell color gene, Orange1. The genomic mapping of a shell color gene in bay scallop improves our understanding of shell color inheritance and may contribute to the breeding of molluscs with desired shell colors.

Identification of Crassostrea ariakensis and related oysters by multiplex species-specific PCR

Genetic markers are needed for rapid and reliable identification of oysters. In this study, we developed multiplex genus- and species-specific PCR markers for the identification of oysters from China. We used the mitochondrial cytochrome oxidase I (COI) and nuclear 28S ribosomal RNA genes for marker development. DNA sequences from different species were obtained from GenBank or by direct sequencing. Sequences were aligned, and genus- and species-specific nucleotides were identified. Primers were designed for genus/species-specific amplification to generate fragments of different sizes. A multiplex set of genus- and species-specific primers from the 28S gene was able to separate C. ariakensis and C. hongkongensis from other species and assign oysters to four genera. A set of species-specific COI primers provided positive identification of all five Crassostrea species from China, C. ariakensis, C. hongkongensis, C. angulata, C. gigas, and C. sikamea in a single PCR. The multiplex PCR assays do not require fluorescence-labeling or post-PCR enzyme digestion, providing a simple, fast and reliable method for the identification of oysters from China.

Its length polymorphism in oysters and its use in species identification

In an effort to develop genetic markers for oyster identification, we studied length polymorphism in internal transcribed spacers (ITS) between major ribosomal RNA genes in 12 common species of Ostreidae: Crassostrea virginica, C. rhizophorae, C. gigas, C. angulata, C. sikamea, C. ariakensis, C. hongkongensis, Saccostrea echinata, S. glomerata, Ostrea angasi, O. edulis, and O. conchaphila. We designed two pairs of primers and optimized PCR conditions for simultaneous amplification of ITS 1 and ITS2 in a single PCR. Amplification was successful in all 12 species, and PCR products were visualized on high-resolution agarose gels. ITS2 was longer than ITS 1 in all Crassostrea and Saccostrea species, whereas they were about the same size in the three Ostrea species. No intraspecific variation in ITS length was detected. Among species, the length of ITS I and ITS2 was polymorphic and provided unique identification of 8 species or species pairs: C. ariakensis, C. hongkongensis, C. sikamea, O. conchaphila, C. virginica/C. rhizophorae, C. gigas/C. angulata, S. echinata/S. glonzerata, and O. angasi/O. edulis. The ITS assay provides simple, rapid and effective identification of C. ariakensis and several other oyster species. Because the primer sequences are conserved, the ITS assay may be useful in the identification of other bivalve species.

Sensitisation identification of stainless steel to intergranular stress corrosion cracking by atomic force microscopy

A new technique was developed for characterisation of stainless steel to intergramilar stress corrosion cracking by atomic force microscopy. The technique proved to be effective in sensitisation identification of AISI 304 stainless steel and might be promising in sensitisation identification of other stainless steels. (c) 2007 Elsevier B.V. All rights reserved.

Cytological and Molecular Identification of Alien Chromatin in Giant Spike Wheat Germplasm

Alien chromosomes of twelve giant spike wheat germplasm lines were identified by C-banding, genomic in situ hybridization (GISH), sequence characterized amplified region (SCAR), and random amplified polymorphic DNA (RAPD). All lines showed a chromosome number of 2n = 42, five of them carried both a pair of wheat-rye (Triticum aestivum-Secale cereal) 1BL/1RS translocation chromosomes and a pair of Agropyron intermedium (Ai) chromosomes, three carried a pair of Ai chromosomes only, three others carried a pair of 1BL/1RS chromosomes only, and one carried neither 1BL/1BS nor Ai chromosome. Further identification revealed that the identical Ai chromosome in these germplasm lines substituted the chromosome 2D of common wheat (Triticum aestivum L.), designated as 2Ai. The genetic implication and further utilization of 2Ai in wheat improvement were also discussed.

Analysis of carbohydrates in a tibetan medicine using new labeling reagent, 1-(2-naphthyl)-3-methyl-5-pyrazolone, by HPLC with DAD detection and ESI-MS identification

A new labeling reagent, 1-(2-naphthyl)-3-methyl-5-pyrazolone (NMP), coupling with liquid chromatography (LC) with electrospray ionization mass spectrometry (ESI-MS) for the detection of carbohydrates from a famous Tibetan medicine is reported. Carbohydrates were derivatized to their bis-NMP-labeled derivatives. The method, in conjunction with a gradient elution, offered a baseline resolution of carbohydrate derivatives on a reversed phase Hypersil ODS-2 column. The carbohydrates such as mannose, galacturonic acid, glucuronic acid, rhamnose, glucose, galactose, xylose, arabinose, and fucose could be successfully detected by UV and ESI-MS. Derivatives showed intense protonated molecular ion at m/z [M+H]+ in positive ion mode. The mass to charge ratios of characteristic fragment ions at m/z 473.0 could be used for the accurately qualitative identification of carbohydrates; this characteristic fragment ion was from the cleavage of C2-C3 bond in the carbohydrate chain giving the specific fragment ions at m/z [MH-CmH2m+1Om-H2O](+) for pentose, hexose, and glyceraldehydes, and at m/z [MH-CmH2m-1Om+1-H2O](+) for alduronic acids, such as galacturonic acid and glucuronic acid (m=n-2, n is carbon atom number of carbohydrate). Compared with the traditional 1-phenyl-3-methyl-5-pyrazolone (PMP) reagent, currently synthesized NMP show the advantage of higher sensitivity to carbohydrate compounds with UV and ESI-MS detection.

Simultaneous determination of monoamine and amino acid neurotransmitters in rat endbrain tissues by pre-column derivatization with high-performance liquid chromatographic fluorescence detection and mass spectrometric identification

A sensitive and efficient method for simultaneous determination of glutamic acid (Glu), gamma-amino-butyric acid (GABA), dopamine (DA), 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) in rat endbrains was developed by high-performance liquid chromatography (HPLC) with fluorescence detection and on-line mass spectrometric identification following derivatization with 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC). Different parameters which influenced derivatization and separation were optimized. The complete separation of five neurotransmitter (NT) derivatives was performed on a reversed-phase Hypersil BDS-C-18 column with a gradient elution. The rapid structure identification of five neurotransmitter derivatives was carried out by on-line mass spectrometry with electrospray ionization (ESI) source in positive ion mode, and the BCEOC-labeled derivatives were characterized by easy-to-interpret mass spectra. Stability of derivatives, repeatability, precision and accuracy were evaluated and the results were excellent for efficient HPLC analysis. The quantitative linear range of five neurotransmitters were 2.441-2 x 10(4) nM, and limits of detection were in the range of 0.398-1.258 nM (S/N = 3:1). The changes of their concentrations in endbrains of three rat groups were also studied using this HPLC fluorescence detection method. The results indicated that exhausting exercise could obviously influence the concentrations of neurotransmitters in rat endbrains. The established method exhibited excellent validity, high sensitivity and convenience, and provided a new technique for simultaneous analysis of monoamine and amino acid neurotransmitters in rat brain. (C) 2008 Elsevier B.V. All rights reserved.

Analysis of primary aromatic amines using precolumn derivatization by HPLC fluorescence detection and online MS identification

2-(2-Phenyl-1H-phenanthro-[9,10-d]imidazole-1-yl)-acetic acid (PPIA) and 2-(9-acridone)-acetic acid (AAA), two novel precolumn fluorescent derivatization reagents, have been developed and compared for analysis of primary aromatic amines by high performance liquid chromatographic fluorescence detection coupled with online mass spectrometric identification. PPIA and AAA react rapidly and smoothly with the aromatic amines on the basis of a condensation reaction using 1-ethyl-3-(3dimethylaminopropyl)-carbodiimide (EDC) as dehydrating catalyst to form stable derivatives with emission wavelengths at 380 and 440 nm, respectively. Taking six primary aromatic amines (aniline, 2-methylaniline, 2-methoxyaniline, 4-methylaniline, 4-chloroaniline, and 4-bromoaniline) as testing compounds, derivatization conditions such as coupling reagent, basic catalyst, reaction temperature and time, reaction solvent, and fluorescent labeling reagent concentration have also been investigated. With the better PPIA method, chromatographic separation of derivatized aromatic amines exhibited a good baseline resolution on an RP column. At the same time, by online mass spectrometric identification with atmospheric pressure chemical ionization (APCI) source in positive ion mode, the PPIA-labeled derivatives were characterized by easy-to-interpret mass spectra due to the prominent protonated molecular ion m/z [M + H](+) and specific fragment ions (MS/MS) m/z 335 and 295. The linear range is 24.41 fmol-200.0 pmol with correlation coefficients in the range of 0.9996-0.9999, and detection limits of PPIA-labeled aromatic amines are 0.12-0.21 nmol/L (S/N = 3). Method repeatability, precision, and recovery were evaluated and the results were excellent for the efficient HPLC analysis. The most important argument, however, was the high sensitivity and ease-of-handling of the PPIA method. Preliminary experiments with wastewater samples collected from the waterspout of a paper mill and its nearby soil where pollution with aromatic amines may be expected show that the method is highly validated with little interference in the chromatogram.

Determination of free fatty acids in bryophyte plants and soil by HPLC with fluorescence detection and identification by online MS

A method for the determination of long and short chain free fatty acids (FFAs), using 1-[2-(ptoluenesulfonate)-ethyll-2-phenylimidazole-[4,5-f-9,10-phenanthrene (TSPP) as labeling reagent, has been developed. Identification of FFA derivatives was carried out by HPLC-MS with atmospheric pressure chemical ionization (APCI) in positive ion mode. Gradient elution on an Agilent Eclipse XDB-C-8 column gave good separation of the derivatives. Excellent linear responses were observed and good compositional data could be obtained from as little as 200 mg of bryophyte plants and soil samples. Facile TSPP derivatization coupled with HPLC-APCI-MS analysis allowed the development of a highly sensitive method for the quantitative analysis of trace level of FFAs from biological and natural environmental samples.