On Temporal Dynamics of Morphological Variations in the Black Sea Mussel Mytilus galloprovincialis Lam.

Temporal variations in morphological characters of the shells were studied in 12 samples of mussels M. galloprovincialis Lam. from the Black Sea commercial collectors that belong to different generations. The samples were shown to be diverse in every studied character and the degree of characters' variability in the samples was different. The morphological diversity of samples diminished with age. Different generations from the same habitat had specific features of age-related variability expressed as different rates of age-related changes and direction and degree of variability. This effect is considered as an index of the influence of ecological conditions on the shell growth and formation.     

Commensals of Mytilus galloprovincialis in the Black Sea: Urastoma cyprinae (Turbellaria) and Polydora ciliata (Polychaeta)

The intensity of infection of the mussel Mytilus galloprovincialis Lamarck in the Black Sea by the turbellarian Urastoma cyprinae (Graff), which lives on its gills, was found to be higher in larger hosts, reaching a maximum in mussels of 50–70 mm length. Greater numbers occured in mussels inhabiting a silty bottom than in cultivated mussels suspended above the bottom. Over the period 1982–1987, U. cyprinae was most numerous in winter and especially so in years that were colder. The spionid polychaete Polydora ciliata (Johnston) also infects M. galloprovincialis, burrowing into the shell. Young spionids of up to 1 mm length occured in mussels with a shell length of 35 mm. Numbers of this commensal reached a maximum in mussels of intermediate size.     

The duration of the meiosis stages in fertilized ovocytes of the mussel Mytilus galloprovincialis Lam. at different temperatures

Duration of meiosis steps in fertilized oocytes of mussel Mytilus galloprovincialis at three levels of development temperature optimum: 8.5, 12 and 17 degrees C. Absolute duration of meiosis stages increases with decreasing of water temperature. Relative duration of analogous stages doesn't depend on temperature conditions. Duration of first meiotic division determined by the time between maximal occurrences of consequent stages, at different temperatures is in two times greater than duration of second division.     

Large-Scale Spatial Dynamics of Intertidal Mussel (Mytilus edulis L.) Bed Coverage in the German and Dutch Wadden Sea

Intertidal blue mussel beds are important for the functioning and community composition of coastal ecosystems. Modeling spatial dynamics of intertidal mussel beds is complicated because suitable habitat is spatially heterogeneously distributed and recruitment and loss are hard to predict. To get insight into the main determinants of dispersion, growth and loss of intertidal mussel beds, we analyzed spatial distributions and growth patterns in the German and Dutch Wadden Sea. We considered yearly distributions of adult intertidal mussel beds from 36 connected tidal basins between 1999 and 2010 and for the period 1968–1976. We found that in both periods the highest coverage of tidal flats by mussel beds occurs in the sheltered basins in the southern Wadden Sea. We used a stochastic growth model to investigate the effects of density dependence, winter temperature and storminess on changes in mussel bed coverage between 1999 and 2010. In contrast to expectation, we found no evidence that cold winters consistently induced events of synchronous population growth, nor did we find strong evidence for increased removal of adult mussel beds after stormy winter seasons. However, we did find synchronic growth within groups of proximate tidal basins and that synchrony between distant groups is mainly low or negative. Because the boundaries between synchronic groups are located near river mouths and in areas lacking suitable mussel bed habitat, we suggest that the metapopulation is under the control of larval dispersal conditions. Our study demonstrates the importance of moving from simple habitat suitability models to models that incorporate metapopulation processes to understand spatial dynamics of mussel beds. The spatio-dynamic structure revealed in this paper will be instrumental for that purpose.     

Identification of Several Cytoplasmic HSP70 Genes from the Mediterranean Mussel (Mytilus galloprovincialis) and Their Long-Term Evolution in Mollusca and Metazoa

The HSP70 protein family consists one of the most conserved and important systems for cellular homeostasis under both stress and physiological conditions. The genes of this family are poorly studied in Mollusca, which is the second largest metazoan phylum. To study these genes in Mollusca, we have isolated and identified five HSP70 genes from Mytilus galloprovincialis (Mediterranean mussel) and investigated their short-term evolution within Mollusca and their long-term evolution within Metazoa. Both sequence and phylogenetic analyses suggested that the isolated genes belong to the cytoplasmic (CYT) group of the HSP70 genes. Two of these genes probably represent cognates, whereas the remaining probably represent heat-inducible genes. Phylogenetic analysis including several molluscan CYT HSP70s reveals that the cognate genes in two species have very similar sequences and form intraspecies phylogenetic clades, differently from most metazoan cognate genes studied thus far, implying either recent gene duplications or concerted evolution. The M. galloprovincialis heat-inducible genes show intraspecies phylogenetic clustering, which in combination with the higher amino acid than nucleotide identity suggests that both gene conversion and purifying selection should be responsible for their sequence homogenization. Phylogenetic analysis including several metazoan HSP70s suggests that at least two types of CYT genes were present in the common ancestor of vertebrates and invertebrates, the first giving birth to the heat-inducible genes of invertebrates, whereas the other to both the heat-inducible genes of vertebrates and the cognate genes of all metazoans. These analyses also suggest that inducible and cognate genes seem to undergo divergent evolution. Electronic Supplementary Material Electronic Supplementary material is available for this article at and accessible for authorised users. [Reviewing Editor: Dr. Yves Van de Peer] Elena Drosopoulou and Nikolas Nikolaidis contributed equally to the present report.     

Genetic Changeability by Loci <Emphasis Type="Italic">COI</Emphasis> mtDNA for Different Coloring of Shell Phenotypes of Black Sea Mussel <Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis> Lam. (Mollusca: Bivalvia: Mytilidae)

The variability of the nucleotide sequences of the fragment of the COI gene of the female genome was studied in four phenotypic groups of the Black Sea mollusk Mytilus galloprovincialis. It was shown that the parameters of genomic diversity (the number of haplotypes, haplotypic and nucleotide diversity, and the number of nucleotide substitutions, including pairwise ones) in mussels with dark shell color are significantly higher than in individuals with light color phenotypes. The revealed differences are related to the peculiarities of ecological preferences of mussels with dark and light shells.     

Electrophoretic investigation of systematic relationships in the marine mussels Modiolus modiolus L., Mytilus edulis L., and Mytilus galloprovincialis Lmk. (Mytilidae; Mollusca)

Genetic variation was assayed electrophoretically at 13–16 loci in Modiolus modiolus, Mytilus edulis, and Mytilus galloprovincialis. High genetic distance ( D ) values were observed between Modiolus modiolus and Mytilus edulis (1.516 ± 0.523) and between Modiolus modiolus and Mytilus galloprovincialis (1.564 ± 0.539), whereas the distance between Mytilus edulis and M. galloprovincialis (0.167 ± 0.118) was rather low. The systematic status ot Mytilus edulis and M. galloprovincialis is discussed in relation to these lindings and the genetic distance values are used to estimate divergence times which in turn are compared with paleontological estimates. The observations of high average heterozygosity in Modiolus modiolus, and high correlations of locus heterozygosity between taxa are discussed briefly.     

Two Genotypes of Pedicularis chamissonis (Scrophulariaceae) Distributed at Mt. Gassan, Japan: Additional Genetic and Morphological Studies

Pedicularis chamissonis Steven, which is broadly distributed from northern Honshu of Japan to southwest Alaska, is known to comprise a few different cpDNA haplotypes grouped into two major (“Northern” and “Southern”) clades. This paper presents on the basis of chloroplast and nuclear DNA analyses that no gene flow exists between the two clades at Mt Gassan where two haplotypes D and J of the Northern and Southern clades occur. The two haplotypes are further distinguished from each other in corolla and leaf shape and the number of flower whorls on an inflorescence axis, a fact indicating that individuals of the two clades should be treated as separate species. At Mt. Gassan and in other regions in general the haplotypes of the Southern clade currently grow at higher altitudes than those of the Northern clade. Based on the difference in habitat as well as the lack of gene flow between the two clades, evolutionary processes resulting in the current distribution of the two genotypes are also briefly discussed. Received 3 October 2000/ Accepted in revised form 4 March 2001     

Study of two species of mussels, Mytilus trossulus and Mytilus galloprovincialis (Bivalvia, Mytilidae) and their hybrids, using PCR markers, in Peter the Great Bay of the Sea of Japan]

Bivalve mollusks of the genus Mytilus (M. trossulus and M. galloprovincialis) occurring in Peter the Great Bay of the Sea of Japan were first studied in Russia. A region of nonrepetitive sequences of the gene encoding the polyphenolic adhesive protein bissus was used as a species-specific genetic marker. After amplification using specific primers, a 126-bp fragment was found to amplify in all representatives of M. galloprovincialis collected from driftwood in the gulf Posset (the southwestern part of Peter the Great Bay). M. trossulus specimens from the same region were shown to have a 168-bp fragment. In Vostok Gulf (the eastern part of Peter the Great Bay), both artificially grown mussels and those from natural habitats contained a 168-bp fragment or two fragments (126- and 168-bp) that corresponded to a hybrid form between the above species. The possibility of using this genetic marker to identify closely related Mytilus strains and their hybrids in similar habitats, near the Primorye coast in particular, was demonstrated. The presence of approximately 9% of hybrid specimens confirms that a zone of hybridization between M. trossulus and M. galloprovincialis may exist in this region.     

Physiological measurements from native and transplanted mussel (Mytilus galloprovincialis) in the canals of Venice. Survival in air and condition index

The Venice Lagoon has been the focus of many environmental studies due to its heavy contaminant load derived from a variety of sources, including industrial activity, oil tanker traffic, and waste runoff from the mainland. In recent years, there has been increasing concern about water quality in the urban areas of Venice related to the discharge of untreated sewage directly into canals, adding to the pollutant load already existing in these areas. One way of gauging the impact of these chemicals is monitoring the local fauna. In the search for good indicators of water quality in the Venice urban area, two physiological indices for mussels-survival in air and condition index-have been evaluated. In 2002, a seasonal study was undertaken; mussels (Mytilus galloprovincialis) were collected in three sites located in the canals of the city and a clean reference site. At the same time, two transplantation experiments were performed, deploying farmed mussels for 1,2, 4, and 12 weeks in the historic centre of Venice and also at a reference site. Data from survival in air test and the condition index of native and transplanted mussels are reported. The results suggest an impact of the complex mixture of pollutants on mussel health status. Both native mussels and those transplanted to the urban area showed reduced survivability in air and decreased condition index values, indicating a less healthy status in animals from the canals of the city. Data are discussed in relation to pollutant bioaccumulation.     

Seasonal Dynamics of Diel Changes in Inshore Benthopelagic Communities of the Black Sea by the Example of the Golubaya Bay (Gelendzhik Town)

Seasonal and diel changes in inshore plankton in the Golubaya Bay (near Gelendzhik Town) were studied at seven daily stations from October 1999 to September 2000. In the night-time, the plankton included both holoplanktonic and demersal species rising to the upper layers (benthopelagic plankton). The role of benthopelagic and holoplanktonic organisms in relation to the time of the day, season, and phase of the moon was determined. Benthopelagic plankton of the Golubaya Bay largely included amphipods (which were the most abundant), mysids, isopods, decapods, tanaids, cumaceans, and polychaetes.__________Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 3, 2005, pp. 349–363.Original Russian Text Copyright © 2005 by Anokhina.     

A population genetic study of the hybrid zone of Mytilus trossulus Gould, 1850 and an introduced species,M. galloprovincialis Lamarck, 1819, (Bivalvia: Mytilidae) in peter the great bay in the Sea of Japan

This paper examines the genetic variability of the Pacific mussel Mytilus trossulus and an introduced Atlantic species, M. galloprovincialis, in the northwestern Sea of Japan (Peter the Great Bay and Kievka Bay). The genotyping of individuals from eight populations was carried out using eight polymorphic enzyme loci and two nuclear DNA markers (Me-5 and ITS-1,2); the occurrence frequency of parent species and their hybrids was determined. The enzyme and nuclear markers demonstrated concordant genetic variation. The genotypes of the native species M. trossulus were predominant in the samples studied. The frequency of the introduced species M. galloprovincialis in the total material was relatively low; however, it reached 42 ± 2% in samples that were collected in Possjet Bay near the town of Zarubino in a zone of active international navigation. In this area the greatest number of hybrids was found as well. It is concluded that the invasion of M. galloprovincialis in the northwestern Sea of Japan is continuing; permanent populations of this mussel appeared in Possjet Bay that were not recorded here previously.     

Morphological and molecular characterization of Aspidisca hongkongensis spec. nov. (Ciliophora,Euplotida) from the South China Sea

The morphology and infraciliature of a new ciliate, Aspidisca hongkongensis spec. nov., a large marine form isolated from the coastal waters near Hong Kong, were investigated. It differs from the congeners by the combination of cell size (about 90×60 μm in vivo), 9–11 conspicuous dorsal ridges, one fine and seven strong frontoventral cirri, six membranelles in anterior portion of adoral zone, and 17–23 membranelles in posterior portion of adoral zone. The comparison with similar congeners clearly supports the distinction of this new species based on morphological and small subunit (SSU) rRNA gene sequence studies. The SSU rRNA gene sequence similarity within the genus is about 75.3–92.1% which indicates that this is a distinct form. Phylogenetic trees based on SSU rRNA gene information show that A. hongkongensis groups with A. leptaspis.     

Morphokaryological variability and divergence of stargazers (Uranoscopus, perciformes) from the Mediterranean Sea basin: I. Divergence and taxonomic state of the Black Sea Stargazer

Based on museum collections, the variability of morphological characters of stargazers (Uranoscopus, Uranoscopidae) from different seas of the Mediterranean Sea basin have been studied. On the basis of the obtained results and data on the karyological divergence of the previously studied populations, stargazers of the Black Sea are regarded as an independent subspecies, Uranoscopus scaber anostomus, differing from the Mediterranean Sea populations in relatively long ventral fins, whose length usually exceeds half of the head length, the presence in most individuals of not less than 12 pyloric caeca, chromosome polymorphism with 2n = 28?C32, NF = 50, and the presence in the karyotype of a pair of marker small metacentric chromosomes. Morphological characters suitable for analysis of morphological divergence of populations of the Mediterranean region have been revealed.