Paralytic shellfish poison as an attractant for toxic snails

The attracting effect of paralytic shell poison (PSP) on eight toxic snail species (Polinices didyma, Natica lineata, N. vitellus, Zeuxis sufflatus, Niotha clathrata, Oliva miniacea, O. mustelina, O. hirasei) and two non-toxic species (Pomacea canaliculata, Satsuma bairdi) was investigated. Eight toxic species were reported to contain tetrodotoxin, and three out of these contained minor PSP. The minimum lethal dose of PSP in most toxic gastropods was estimated to be more than 150 MU PSP/20 g body weight, but in non-toxic gastropods was less than 15 MU PSP/20 g body weight. After the attracting test, all toxic gastropods showed significant positive linear relationship (Y=3.716X+0.363, r=0.8427) between comparative attracting variation and the toxicity reported. The relationship between PSP resistance ability and the toxicity also had a positive correlation (Y=0.91X+210.090, r=0.6803). However, the non-toxic species showed a negative response. This indicates that PSP is an attractant for toxic snails.     

Molecular phylogenetic relationships of puffer fish inferred from partial sequences of cytochrome b gene and restriction fragment length polymorphism analysis

Phylogenetic relationships among puffer fish were investigated by comparing cytochrome b gene sequences and restriction endonuclease assays of 16 species from Taiwan. DNA was prepared for sequencing by PCR. No variation in sequences was detected among individuals within each species. Direct estimates of mitochondrial cytochrome b gene sequence divergence among 16 puffer fish were from 3.41 to 31.78%. Different restriction patterns were found among 16 puffer fish with 10 restriction endonucleases, whereas no variation in patterns was detected among individuals within each species. The polymorphisms obtained by RFLP have provided a new set of genetic markers for the accurate identification of sibling puffer species. It is the first molecularly based study of puffer diversity and sheds light on the evolution and taxonomy of this major puffer fish family.     

Structural transformation of oyster,hard clam,and sea urchin shells after calcination and their antibacterial activity against foodborne microorganisms

Fisheries Science - The aim of this study was to evaluate the antibacterial properties of oyster, hard clam, and sea urchin shell powders as a result of calcination. After subjection to calcination...     

Seasonal variations of free amino acids and nucleotide-related compounds in the muscle of cultured Taiwanese puffer Takifugu rubripes

SUMMARY: Seasonal variation in the level of extractive nitrogenous components was investigated in the muscle of puffer Takifugu rubripes cultured in two different areas of Taiwan. There were no seasonal and regional variations in the proximate composition of the fish. Of the free amino acids (FAA) in the muscle of puffer, the predominant one was taurine, followed by glycine, lysine, and alanine. Among nucleotide-related compounds, inosine monophosphate (IMP) and guanosine monophosphate (GMP) were the most prominent compounds. The total nucleotide-related compounds in the muscle of puffer were higher in July and November than those in the other months. The level of total taste-active components including glycine, alanine, arginine, GMP, IMP, and adenosine 5'-monophosphate was much higher in the muscle of puffer collected from July to January. Therefore, the puffer is probably more palatable in these periods.     

Neurotoxin tetrodotoxin as attractant for toxic snails

ABSTRACT:   The attracting effect of a small dose of tetrodotoxin (TTX) on eight toxic snail species ( Polinices didyma, Natica lineata, Natica vitellus, Zeuxis sufflatus, Niotha clathrata, Oliva miniacea, Oliva mustelina and Oliva hirasei ) and two non-toxic species ( Pomacea canaliculata and Satsuma bairdi ) was investigated. Each toxic snail species was determined to contain TTX. The minimum lethal dose of TTX for most toxic snails was estimated to be >44.5 µg TTX/20 g body weight, but for non-toxic snails it was <3.6 µg TTX/20 g body weight. After the attracting test, it was found that for all toxic snails there was a significantly positive relationship between the comparative attracting variation and the toxicity reported, and this relationship was linear ( y  = 5.895 x  + 3.443, r  = 0.806). The relationship between TTX resistance ability and toxicity also had a positive correlation ( y  = 0.113 x  + 52.447, r  = 0.814). However, non-toxic species showed a negative response. The more toxic snails appeared to prefer TTX, indicating that TTX is an attractant for toxic snails.     

Evaluation of antioxidant properties and biofunctions of polar,nonpolar, and water-soluble fractions extracted from gonad and body wall of the sea urchin Tripneustes gratilla

This study was performed to compare the various bioactivities of water-soluble, polar, and nonpolar extracts from the edible part (gonad) and waste (body wall) of the sea urchin Tripneustes gratilla. During antioxidant activity screening, these three extracts from both gonad and body wall showed various antioxidant activities in different tests. During human skin fibroblast (CCD966SK) viability and collagen screening, only water-soluble and polar extracts from gonad and body wall were observed to promote cell viability, while the water-soluble gonad extract promoted the collagen-generating activity of CCD966SK cells. The water-soluble and polar extracts from gonad and body wall showed proliferative activity towards different cell types. In contrast, the nonpolar extracts of gonad and body wall exerted antiproliferative effects on most tumor cells. These results indicate that the bioactivities of sea urchin extracts depend on the part of the urchin that the extract was taken from as well as the extraction method used.     

Preliminary study on puffer fish proteome-species identification of puffer fish by two-dimensional electrophoresis

The aims of this work were to determine the differential characterization of the urea soluble protein components of puffer fish species and to establish a preliminary proteomic database using an immobilized pH gradient two-dimensional electrophoresis (2DE) technique. The puffer fish muscle proteins resolved into 171-260 spots in the 2DE gels, with a pI range of 3-10 and molecular mass range of 7.4-205.0 kDa, following Comassie blue staining. Puffer fish muscle proteins fell in the region with pI values of 3.5-7.0, and molecular masses of 7.4-45.0 kDa were well-resolved and were good for species comparison. The more acidic proteins of lower molecular masses showed species specific characteristics. Therefore, the species of puffer fish can be differentiated from the comparison of the characteristic 2DE protein patterns.     

Applying DNA techniques to the identification of the species of dressed toasted eel products

To differentiate the species of processed eel products, the gene identification of four fresh eel species was first established and the species of eel products collected from markets were investigated. Polymerase Chain Reaction (PCR) and sequence analysis were used to determine the genetic variation in a 362-nucleotide region of the mitochondrial cytochrome b gene in four fresh eels including Anguilla japonica, Anguilla anguilla, Anguilla rostrata, and Muraenesox cinereus. It was found that each eel species had a unique genotype, which was no different among fresh, frozen, and sterilized meats. The restriction enzyme HinfI could differentiate the species of A. japonica and A. rostrata but could not differentiate A. anguilla and M. cinereus. Another restriction enzyme, Sau96 I, was valuable in the differentiation of M. cinereus from the other three species of Anguilla. By applying PCR and restriction enzymes, the species of 12 commercial eel products were identified as A. japonica (9 samples), A. anguilla (2), and A. rostrata (1). This indicated that the sequence and restriction enzyme cutting site analyses were very usable to authenticate species of different processed eel products.