Lipid composition of the epidermal gel secretion from the Arabian Gulf catfish (Arius thalassinus Ruppell)

Lipids associated with a threat induced epidermal gel secretion from the catfish, Arius thalassinus, have been analyzed. Phospholipids, neutral lipids and glycolipids are all present and each of these subclasses has been analyzed by thin layer and gas chromatography with a general similarity with membrane lipids being noted. The epidermal gel lipids differed from total liver lipids of the catfish. Fatty acid analysis showed the gel lipid to be rich in the unsaturated fatty acids: oleate (omega 7, C18:1), arachidonate (omega 6, C20:4), and docosahexaenoate (omega 3, C22:6). Some prostaglandins were quantitated in lipid extracts from the epidermal gel.     

A hemolytic protein secreted from epidermal cells of the Arabian Gulf catfish, Arius thalassinus (Ruppell)

1. A fright or shock induced toxic secretion (gel) from the epidermis of the Arabian Gulf catfish, Arius thalassinus, exhibits hemolytic activity when tested against red blood cells from many different sources. 2. An enzyme with hemolytic activity, which represents 1.1% of the total soluble gel protein fraction, has been purified to homogeneity. 3. Molecular sieve chromatography and SDS polyacrylamide gel electrophoresis of the purified protein indicate a mol. wt of 34,000. 4. One additional protein component with hemolytic activity was found in the epidermal secretion. 5. Specific activity of the catfish epidermal factor is 20.6 units/mg protein, a level somewhat lower than those of most protein hemolytic factors. 6. The catfish hemolytic factor was not ichthyotoxic when tested against small fish and did not cause lethality when administered intravenously to rabbits.     

Purification and properties of a hemagglutination factor from Arabian Gulf catfish (Arius thalassinus) epidermal secretion

A galactose specific lectin was isolated from an epidermal proteinaceous gel secretion of the Arabian Gulf catfish, Arius thalassinus, Ruppell. The lectin was extracted and purified to near homogeneity by exclusion chromatography, affinity chromatography and isoelectric focusing. The lectin appears to be active as a single polypeptide chain with a mol. wt near 200,000, which can form oligomers and heteropolymers. The lectin comprises about 2% of the total gel protein, lacks carbohydrates and contains no unusual types or amounts of amino acids. The lectin agglutinates a wide range of red blood cell types.     

Platelet activating factors (AGEPC) from epidermal secretions of the Arabian Gulf catfish, Arius bilineatus, which stimulate wound healing

High levels of platelet activating factor (PAF) activity were demonstrated by platelet aggregation and serotonin release assays to be present in fright induced epidermal secretions of the Arabian Gulf catfish, Arius bilineatus (Valenciennes, 1840). The PAF activity was purified by thin-layer chromatography. Mass spectral analysis combined with chemical and enzymatic modification of the purified PAF and inhibitor studies indicated that PAF activity was due to the presence of 1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine (AGEPC) molecules. The total AGEPC concentration in the epidermal secretions based on PAF assays was 8 x 10(8) M, well above the threshold level for platelet activation which is near 5 x 10(-11) M. Thus, stimulated epidermal secretory cells of Arius bilineatus supply platelet activating molecules at physiologically high concentrations to sites of injury.     

Comparative biochemical and pharmacological properties of epidermal secretions from Ariid catfish of the Arabian Gulf

1. Comparative biochemical and pharmacological studies on epidermal secretions from three species of Ariid catfish were carried out to determine whether they share common properties. 2. Protein compositions are generally similar, but show some differences in size and numbers of proteins. 3. Lipids also differ. However, seasonal and dietary changes in lipid compositions exceed the differences among species. 4. Enzymes in the secretions appear common to each fish species, though some differences are noted in relative activities. 5. Toxicity responses of rabbits to injections with secretions from each of the catfish species indicated that two were lethal, with similar lethal dose levels when injected intravenously. 6. Secretions from all three catfish induced changes in plasma enzyme levels indicative of heart and liver damage, and also induced changes in blood glucose and cholesterol levels.     

中国海鲇属海鲇的分类学厘定及一新记录种--双线海鲇(鲇形目:海鲇科)

长期以来,国内绝大多数有关研究者将海鲇属Arius中腭骨齿单侧3群的个体鉴定为海鲇A．thalassinus。基于中国科学院动物研究所标本馆馆藏海鲇标本的研究发现,标本中存在两种腭骨齿的分化类型;经文献查证,其中一种应为双线海鲇A．bilineatus,该种在我国尚未见有研究报道,为一新记录种。双线海鲇与海鲇外形相似,但前者吻较钝,唇薄,腭骨齿于前部相连,游离脊椎骨数目较多(46—51 vs 38—43),臀鳍鳍条数较多(15—18 vs 1316),无囟门沟,从而可与后者相区别[动物学报51(3)：423—430,2005]。     

Arius peronii: A distinct species of Fork-tailed catfish (Pisces: Ariidae)

An Indian Ocean ariid catfish Arius peronii (Valenciennes) is redescribed. It is compared with the morphologically similar Ketengus typus Bleeker.     

Distribution and morphology of the ampullary organs of the salmontail catfish,Arius graeffei

Whole body staining of Arius graeffei revealed that ampullary pores cover the body with their highest densities occurring on the head and lowest densities on the mid‐ventral surface. Each ampullary organ consists of a long canal (0.2–1.75 mm) passing perpendicular to the basement membrane, through the epidermis into underlying dermal connective tissues, curving thereafter to run roughly parallel to the epidermis. Histochemical staining techniques (Alcian blue and Lillie′s allochrome) indicate that the canals contain a neutral to acidic glycoprotein‐based mucopolysaccharide gel that varies in composition along the length of the canal. Collagen fibers, arranged in a sheath, surround a layer of squamous epithelium that lines each ampullary canal. At the proximal end of the canal, squamous cells are replaced by cuboidal epithelial cells that protrude into the lumen, thus constricting the lumen to form a small pore into the ampulla. The ampulla is lined with receptor and supportive cells. The numerous (60–120) pear‐shaped receptor cells bear microvilli on their luminal surface. Two forms of receptor cells exist in each ampullary organ: basal and equatorial receptor cells. Each receptor cell is connected to an unmyelinated nerve. Each receptor cell is surrounded by supportive cells on all but the apex. Tight junctions and underlying desmosomes occur between adjacent receptor and supportive cells. This form of ampullary organ has not previously been described for teleosts. J. Morphol. 239:97–105, 1999. © 1999 Wiley‐Liss, Inc.     

A new Neocalceostomatid (Monogenoidea) from the gills of the blackfin sea catfish, Arius jella (Siluriformes: Ariidae), in the Bay of Bengal, India

Thysanotohaptor n. gen. (Neocalceostomatidae) is proposed to accommodate Thysanotohaptor rex n. sp. collected from the gills of the blackfin sea catfish Arius jella Day (Siluriformes: Ariidae) from off the coast of Visakhapatnam, Bay of Bengal, Andhra Pradesh, India. Thysanotohaptor is differentiated from the other known neocalceostomatid genera by its species having multiple postgermarial testes (single testis in species of Neocalceostoma and Neocalceostomoides ), lacking a transverse bar associated with the ventral anchor pair (present in species of Neocalceostoma ), and possessing a disc-shaped haptor with a pleated marginal frill (frill absent in Neocalceostomoides spp.; Neocalceostoma spp. with delicate marginal membranes). The Neocalceostomatidae is considered valid within the Order Dactylogyridea based on its members having a haptor armed with 10 marginal and 4 ventral hooks and a germarium having a distal loop prior to uniting with the ootype; the family is not assigned to a suborder of Dactylogyridea because of uncertainty in part about the way in which the distribution of haptoral hooks evolved within the taxon.     

Gonapodasmius epinepheli n. sp. (Didymozoidae) from the grouper Epinephelus tauvina from the Arabian Gulf

A new species, Gonapodasmius epinepheli (Didymozoidae: Gonapodasmiinae), is described from the fish Epinephelus tauvina from the Arabian Gulf. It differs from most other members of the genus in the presence of a bulbous swelling at the distal end of the ovary, the presence of a characteristic bulge in the genital junction region, in the dense mass of glandular cells around the intestinal limbs and in the presence of an empty metraterm and vas deferens in the male and female respectively. The new species represents the first record of a didymozoid trematode from fishes in the Arabian Gulf.     

Macrozooplankton studies in Kuwait Bay (Arabian Gulf). I: Distribution and composition of the ichthyoplankton

Fifty taxa of fish larvae were identified during a 12 monthstudy in Kuwait Bay. Dominants included ‘Sparidae-type’larvae, clupeids and gobies. Peak numbers and types of larvaeoccurred during late spring/early summer with the minimum duringwinter. The bay could be divided into three subareas based uponfaunal, sedimentary and hydrographic characteristics. Low larvalconcentrations were generally found in the vicinity of the Khoral Sabiya—an area of below average salinities. Westernbay stations had either the highest mean temperatures and/orsalinities and low larval densities. During spring and summer,only goby and clupeid larvae were more abundant here than inthe outer bay. Most of the dominants, particularly gobies, Bregmacerosand pomadasyids, occurred at above average concentrations atthe northeastern and outer bay stations.     

New species of genera Tintinnopsis, Metacylis and Eutintinnus (Ciliophora, Spirotrichea, Tintinnida) from the Kuwaiti waters of the Arabian Gulf

The Kuwaiti waters occupy the northwestern part of the Arabian Gulf. These waters are shallow, well mixed, and characterized by a high level of biological productivity. Tintinnids form an important component of the microzooplankton community in Kuwaiti waters. They are particularly abundant in the northern waters of Kuwait, as well as in the waters of Kuwait Bay. However, the diversity of the tintinnid species has not been studied. Tintinnids were collected from Kuwaiti waters during a 1-year zooplankton survey, and tintinnid species were identified. In this paper four new species of tintinnids (Tintinnopsis failakkaensis, Metacylis pythos, Eutintinnus conicus, and E. contractus) are described from Kuwaiti waters. All these species occur commonly in these waters. Statistical comparative analysis is carried out on the basis of measurements taken from 400 specimens of tintinnids from Kuwaiti waters.     

Taste Responses to Binary Mixtures of Amino Acids in the sea catfish, Arius felis

In vivo electrophysiological recordings in the sea catfish,Arius felis, showed that the magnitude of the integrated facialtaste responses to binary mixtures of amino acids was predictablewith knowledge obtained from previous cross-adaptation studiesof the relative independence of the respective binding sitesof the component stimuli. Each component from which equal aliquotswere drawn to form the mixtures was adjusted in concentrationto provide for approximately equal reponse magnitudes. The magnitudeof the taste responses to binary mixtures whose component aminoacids showed minimal cross-adaptation was significantly greaterthan that to binary mixtures whose components exhibited considerablecross-reactivity. There was no evidence for mixture suppression.The relative magnitude of the taste responses in the sea catfishto stimulus mixtures is similar to that previously reportedfor olfactory receptor responses in the freshwater channel catfishand chorda tympani taste responses in the hamster. Chem. Senses21: 45–53, 1996.     

New species and records of polyehaete annelids from Kuwait, Arabian Gulf

A collection of Polychaeta made by the author during 1969 from the coast of Kuwait has been studied. Nineteen species, belonging to 17 genera and 11 families, are described. Nine species are named as new to science (two new genera) and ten species are recorded as new to the fauna of the Arabian Gulf. Also, the available information on the geographical distribution has been given for each new record.     

Morphology and tyrosine-hydroxylase immunohistochemistry of the systemic secondary vessel system of the blue catfish,Arius graeffei

Fish have a secondary vessel system which emerges from the primary vasculature via large numbers of coiled origins. The precise role of this vessel system is unknown. Vascular casting techniques and scanning electron microscopy reveal that the secondary vessels of the blue catfish, Arius graeffei, originate from dorsal, lateral, and ventral segmental primary arteries and from the caudal dorsal aorta. These vessels anastomose with each other to form larger secondary arteries which parallel the primary vessels for their entire length. Secondary vessels do not appear to form a capillary bed in the skin in A. graeffei as they do in some fish species. Coiled secondary vessel origins are abundant within the tunica media and adventitia of the primary vessels from which they emerge. The origins of the secondary vessels are surrounded by the extensive cytoplasmic processes of specialized endothelial cells. These processes extend for up to 6 μm into the lumen of the primary vessel. Ultrastructurally the coiled secondary capillaries consist of an endothelial cell tube which is surrounded by a single layer of pericytes. These endothelial cells extend large numbers of microvilli into the lumen of the coiled secondary capillary. Nerve terminals are commonly associated with the coiled secondary capillaries. Immunohistochemistry has revealed the presence of tyrosine-hydroxylase, an enzyme involved in catecholamine synthesis in nerve varicosities close to secondary vessels in A. graeffei. This vessel system could therefore be regulated by adrenergic nerves. © 1996 Wiley-Liss, Inc.