I. P. Vladychenskaya

In vitro and in silico analysis of the predicted human MOB gene encoding a phylogenetically conserved transmembrane protein.

A novel evolutionary conserved human MOB gene of seven exons is predicted on the chromosome 10. MOB is supposed to express predominately in brain. At least three types of MOB transcripts are proposed. A protein encoded by MOB is five-pass transmembrane molecule.

Adaptive strategy of the Porcellanasterid sea stars

Morphological–functional analysis suggests that the adaptations of sea stars of the family Porcellanasteridae to burrowing and deposit feeding are related to morphological simplification. This simplification led to reduction of the morphological structures responsible for respiration (papulae and paxillae), decrease in the number of cribriform organs, reduction of body size, and retention of juvenile characters by adults. The forced-circulation water system inside the burrow also changes. The water generated by the cribriform organs becomes upwardly directed. The adaptive strategy in the family is characterized by intensification of nonselective deposit feeding by means of active moving within the muddy sediment and removal of fecal materials from the burrow.

Molecular genetic markers of intra- and interspecific divergence within starfish and sea urchins (Echinodermata)

A fragment of the mitochondrial COI gene from isolates of several echinoderm species was sequenced. The isolates were from three species of starfish from the Asteriidae family (Asterias amurensis and Aphelasterias japonica collected in the Sea of Japan and Asterias rubens collected in the White Sea) and from the sea urchin Echinocardium cordatum (family Loveniidae) collected in the Sea of Japan. Additionally, regions including internal transcribed spacers and 5.8S rRNA (ITS1–5.8S rDNA–ITS2) were sequenced for the three studied starfish species. Phylogenetic analysis of the obtained COI sequences together with earlier determined homologous COI sequences from Ast. forbesii, Ast. rubens, and Echinocardium laevigaster from the North Atlantic and E. cordatum from the Yellow and North Seas (GenBank) placed them into strictly conspecific clusters with high bootstrap support (99% in all cases). Only two exceptions–Ast. rubens DQ077915 sequence placed with the Ast. forbesii cluster and Aph. japonica DQ992560 sequence placed with the Ast. amurensis cluster–were likely results of species misidentification. The intraspecific polymorphism for the COI gene within the Asteriidae family varied within a range of 0.2-0.9% as estimated from the genetic distances. The corresponding intrageneric and intergeneric values were 10.4-12.1 and 21.8-29.8%, respectively. The interspecific divergence for the COI gene in the sea urchin of Echinocardium genus (family Loveniidae) was significantly higher (17.1-17.7%) than in the starfish, while intergeneric divergence (14.6-25.7%) was similar to that in asteroids. The interspecific genetic distances for the nuclear transcribed sequences (ITS1–5.8S rDNA–ITS2) within the Asteriidae family were lower (3.1-4.5%), and the intergeneric distances were significantly higher (32.8-35.0%), compared to the corresponding distances for the COI gene. These results suggest that the investigated molecular-genetic markers could be used for segregation and identification of echinoderm species.

Taxonomic position of the family Porcellanasteridae within the class Asteroidea

The phylogenetic relationships and taxonomic position of sea stars of the family Porcellanasteridae have been a subject of debate for over a hundred years. In this paper, the methods of molecular phylogenetic analysis were used to solve these issues. The nucleotide sequences of fragments of the mitochondrial gene of subunit 1 of cytochrome oxidase (COI) and those of the 16S rRNA gene were obtained for 9 and 6 species of porcellanasterids for the first time, respectively. The phylogenetic trees including these sequences indicate the nearest relationships of the family Porcellanasteridae with the families Ctenodiscidae and Goniopectinidae, thereby supporting the validity of the allocation of these three families in the suborder Cribellina.

Sea urchins of the genus Gracilechinus Fell & Pawson, 1966 from the Pacific Ocean: Morphology and evolutionary history

Abstract Gracilechinus is a widely distributed genus of regular echinoids with a centre of species diversity in the North Atlantic (five of 10 species). Only three species of this genus are known from the Pacific Ocean: Gracilechinus multidentatus, G. euryporus and G. lucidus. The first two species were previously assigned to the genus Echinus, which differs from Gracilechinus in ambulacral tuberculation. According to our data, all three Pacific species possess ambulacral tuberculation characteristic of the genus Gracilechinus and differ from each other in the structure of the valves of tridentate pedicellariae and primary spines. Assignment of these three species to the genus Gracilechinus is also confirmed by phylogenetic analysis of the 657 bp fragment of the COI gene. The COI tree provides evidence for the validity of the genera Gracilechinus and Echinus and agrees in general with morphological data. Among species of Gracilechinus, two lineages are distinguished on the COI tree, differing in the shape of the tridentate pedicellariae valves. One lineage comprises only the North Atlantic species Gracilechinus alexandri, the other one includes the North Atlantic, South Atlantic and Pacific species. The genus Gracilechinus apparently originated in the North Atlantic and only representatives of the second lineage have penetrated the South Atlantic and the Pacific.