First record of a rare pelagic octopod,Ocythoe tuberculata (Cephalopoda: Ocythoidae), in Korea

The family Ocythoidae is found throughout the temperate and subtropical waters of the world’s ocean and contains a single species, Ocythoe tuberculata. Recently, a single female specimen of the rare pelagic species O. tuberculata was collected off Uljin in the East Sea/Sea of Japan of Korea by squid jigging for the first time. The appearance of this species could be considered as evidence of the changes in species distribution of sea surface. However, further studies are required to investigate whether this phenomenon is temporary or continuous.     

生于菊科植物上的两个链格孢新种

报道生于菊科植物上的两个链格孢新种:瘤链格孢Alternariatuberculata和莴苣链格孢Alternarialactucae。二者分生孢子隔膜均增厚,但瘤链格孢的分生孢子表面具瘤状突起,莴苣链格孢的分生孢子具长的假喙。模式标本保存在山东农业大学植物病理学标本室(HSAUP)。     

First Record of Tropical Crabs <Emphasis Type="Italic">Portunus sanguinolentus</Emphasis> (Herbst, 1783) and <Emphasis Type="Italic">Plagusia depressa tuberculata</Emphasis> Lamarck, 1818 in Peter the Great Bay,Sea of Japan

Crabs Portunus sanguinolentus (Herbst, 1783) and Plagusia depressa tuberculata Lamarck, 1818 were found in Peter the Great Bay (Sea of Japan) on a drifting buoy. The occurrence of the members of tropical fauna along the coast of Primorye was due, in all likelihood, to the enlargement of the amount of anthropogenic garbage transported with sea currents that serves as a substrate for settlement of different marine organisms.Original Russian Text Copyright © 2005 by Biologiya Morya, Kepel, Tsareva.     

Characterization and Quantification of Chitosan Extracted from Nacre of the Abalone Haliotis tuberculata and the Oyster Pinctada maxima

This study was performed to characterize and quantify chitosan by simple physicochemical methods (infrared spectroscopy and potentiometric measurements). These procedures were validated with well-characterized chitosan before being used to investigate chitosan in nacre of the abalone Haliotis tuberculata and of the giant oyster Pinctada maxima. Potentiometric study revealed a chitosan extract from the nacre of H. tuberculata with a degree of deacetylation of around 88% and an intrinsic pK of 6.5. According to infrared and potentiometric data, a low yield (η) of extraction was calculated (η= 0.064%). For experiments performed on the nacre of P. maxima, and in spite of more stringent deacetylation conditions, results suggested that a chitin-protein complex (η= 0.053%) was isolated rather than chitosan. Received February 16, 2000; accepted July 4, 2000.     

Duplication and selection on abalone sperm lysin in an allopatric population

While gene duplication is a major source of evolutionary novelty, the importance of this process in reproductive protein evolution has not been widely investigated. Here, we report the first known case of gene duplication of abalone sperm lysin in an allopatric subspecies found in the Eastern Atlantic, Haliotis tuberculata coccinea. Mass spectrometry identified both copies of the lysin protein in testis tissue, and 3-dimensional structural modeling suggests that both proteins remain functional. We also detected positive selection acting on both paralogs after duplication and found evidence of a recent selective sweep. Because H. t. coccinea occurs in geographic isolation from other abalone species, these findings suggest that the evolution of lysin is not driven to create reproductive barriers to unfit hybrid formation with an overlapping species. Instead, sexual selection or sexual conflict acting during abalone fertilization could be responsible for the recent positive selection on this protein. The presence of multiple, rapidly evolving lysin genes in H. tuberculata presents an opportunity to study the early stages of diversification of a protein whose function is well understood.     

Microsatellite and morphological analysis of population structure in the parthenogenetic freshwater snail Melanoides tuberculata: insights into the creation of clonal variability

The distribution of variability was studied at various geographical scales in the tropical freshwater snail Melanoides tuberculata, in order to analyse the role of factors shaping this distribution, including the mating system and population dynamics. This parthenogenetic polyploid species reproduces mainly asexually, with males occurring at low frequency. About 800 individuals (38 sites) were sampled from Africa and the Middle East, where the species originated, and from recently colonized habitats in South and Central America, and especially the island of Martinique. We first described variation of general aspects and ornamentation of the shells. This analysis confirms the existence of discrete morphs. Second, individuals were studied at three microsatellite loci, showing that each morph is a genetic clone with some minor variation compatible with models of microsatellite evolution. The genetic analysis also showed much more variation within than between clones. However, two populations from Africa exhibited a large amount of variability, and a mixture of sexual and asexual reproduction might explain these genetic patterns. The worldwide distribution of variability is, therefore, compatible with the African origin of the species, and the introduction of a few clones in other parts of the world. These results also suggest that the distribution of variability in Martinique is influenced by flooding events, and that two morphs from Martinique can be interpreted as hybrids between two pre-existing morphs, based on morphological, genetic and geographical arguments.     

Biosorption of Cadmium from Aqueous Solution by Shell Dust of the Fresh Water Snail Melanoides tuberculata

ABSTRACT The metal bioadsorption potential of shell dust of the freshwater snail Melanoides tuberculata (MTSD) was evaluated under laboratory conditions using cadmium as a model metal. As bioadsorbent, MTSD exhibited a biosorption capacity of 27.03 mg g^?1 at pH 6, indicating potential to remove cadmium from aqueous solution. The adsorption data fit more to the Langmuir (R² = 0.998) equation than the Freundlich (R² = 0.761) equation at equilibrium condition. The kinetics of biosorption followed the pseudo-second-order model (R² = 0.999) better than the Lagergren model (R² = 0.676), as was evident from the regression analysis. The presence of calcium ions appears to have facilitated ion exchange with cadmium along with the binding of different functional groups, as revealed through Fourier transform infrared (FT-IR) analysis. It is apparent from these observations that MTSD can act as low-cost and efficient bioadsorbent for cadmium bioremediation from aquatic habitats. Use of the shells of M. tuberculata for metal biosorption will promote the utility of a waste material of biological origin for bioremediation of heavy metals such as cadmium.     

Nebela tuberculata comb. nov. (Arcellinida), its History and Ultrastructure

SYNOPSIS. The name Nebela tuberculata comb. nov. is proposed for the testate ameba formerly known as Difflugia tuberculata (Wallich, 1864) Archer, 1867. The generic reassignment is based upon the test construction material which is shown, by electronmicrographs and X-ray diffraction, to be autogenous regular and irregular silicious rods. A brief history of the animal is recounted utilizing works of several authors who have encountered the ameba over the last century.     

Comparative host reaction to Angiostrongylus malaysiensis (Nematoda) in three species of snails

Infection with Angiostrongylus malaysiensis was studied by means of tissue squash preparations and histological sections in three species of Malaysian aquatic snails: Lymnaea rubiginosa, Physastra sumatrana, and Melanoides tuberculata. Development to the third stage occurred normally in L. rubiginosa. The biphasic tissue reaction in this snail was similar to that described in Biomphalaria glabrata infected with A. cantonensis. However, the final architecture of the granuloma differed in the two hosts with the cells in the L. rubiginosa granuloma often appearing more vacuolated and less flattened. Nematode development in P. sumatrana was abnormal, with larvae beyond the early first stage occurring in only 21% of infected snails. The highly variable cellular reactions against larvae in P. sumatrana, even within the same snail, probably reflect the differing degrees of maturation attained by individual larvae. Except in one case, no infection of M. tuberculata occurred, presumably as a result of its impenetrable epithelia.