New data on the distribution and feeding habits of jellyfish in the Northwest Pacific

In June and July of 2012, the jellyfish catches in the northeastern portion of the surveyed Pacific waters off the Kuril Islands substantially exceeded those in the southwestern portion. This indicates that jellyfish disperse over the studied area predominantly from the southern Bering Sea and from the eastern coast of Kamchatka. Their strobilation probably takes place as well on the shelf and continental slope of eastern Kamchatka. The distribution of jellyfish with medium-sized bells does not show any geographic pattern; the aggregations that are formed are mixed regarding the original locality of individuals. Jellyfish occur within a broad range of surface water temperatures and their catches have declined significantly only in the southeast of the area of surveys near the Subarctic Front. As is seen from the data we compared, not only the abundance of jellyfish, but their feeding activity and, as a consequence, the amount of consumed food decreased by an order of magnitude during the cold season (in the spring 2011). However, irrespective of the season, the largest quantities of food were recorded in the largest and most numerous jellyfish (Phacellophora camtschatica, Chrysaora melanaster). The quantitative results of the studies on the diet of jellyfish may be somewhat underestimated, as fragile jellyfish bodies are easily damaged in trawl nets and evaluating the diet is possible only for intact individuals. Use of specialized catching gear in the future may help us to specify the feeding dynamics in jellyfish, as well they may provide an opportunity to observe their feeding behavior. At the same time, quantitative estimates of the daily-food intake in jellyfish can be obtained only by taking the rates of digestion and prey consumption found under laboratory conditions into account, with their subsequent verification in balance models.     

Position of the genera <Emphasis Type="Italic">Lycenchelys</Emphasis> Gill and <Emphasis Type="Italic">Lycodapus</Emphasis> Gilbert in the family zoarcidae (Perciformes: Zoarcoidei) inferred from molecular genetic analysis

Sequence variation of the mitochondrial COI, cytochrome b, and 16S RNA genes, as well as nuclear RNF213 gene was examined in the genera Lycenchelys and Lycodapus with the purpose of determination of their positions in the system of the family Zoarcidae. It was demonstrated that the genus Lycodapus was considerably closer to the generic group of Lycogramminae (Lycogrammoides, Bothrocara, Allolepis, Bothrocarhichthys) than the genus Lycenchelys. However, on the phylogenetic trees both of these genera were located in the clade of the subfamily Lycodinae. Genetic heterogeneity of the genus Lycenchelys, represented by two species groups differing in distribution patterns (northeastern Pacific and Antarctic) and showing more profound differences than the genera of subfamily Lycodinae, was demonstrated.     

Timeline of the evolution of eelpouts from the suborder Zoarcoidei (Perciformes) based on DNA variability

Based on the analysis of variability of mitochondrial and nuclear DNA and calibration of the molecular clock using the paleontological data, the divergence time of the eelpouts is assessed. The temporal frames of the evolution of the suborder Zoarcoidei are restricted to the Late Oligocene and the middle of the Late Miocene, within a diapason of approximately 12 Ma. The families Bathymasteridae and Cebidichthyidae were the first to separate from the common ancestor, 14.7–22.5 and 13.1–19.1 Ma, respectively. The differentiation of other families occurred between the Middle and the Late Miocene approximately 10–15 Ma. The period from the Late Miocene to the Mid-Pliocene (3.6–7.8 Ma), most likely, was the time of the appearance and distribution of the present species of the suborder. Assessment of the DNA divergence rate in the eelpouts conducted in this study is in accordance with known evolutionary scenarios and with key steps of geological development of the World Ocean.     

The final stage of division of the intermediate cell in a Sarcocystis muris muscle cyst

At least two functions of the micropore, one of the zoite's apical organelles, have been established on examining S. muris intermediate cells. The micropore is known to function primarily as an ultracytostome for taking up the food. The newly discovered function of the micropore appears to be involved in the final step of daughter cell separation in dividing intermediate cell. The micropores seem to be the sites where daughter cells find their exit from the mother cell. In addition, the pattern of the daughter cell pellicle formation was followed.     

Catecholamine-induced changes of the kinetic properties of adrenergic receptors of the myocardium

The pattern of changes in kinetic properties of beta-adrenoreceptor (Cd, c+ and c-) relative to anapriline adrenoblocker under conditions of muscle perfusion by catecholamines has been estimated on papillary cardiac muscles of the rat as based on the isometric voltage. A priority increase of the receptors' affinity to the blocker is determined, that may be a result of changes in microviscosity of the lipid sarcolemma bilayer.