Otolith Morphology and Relationships of Several Fish Species of the Suborder Scorpaenoidei

Journal of Ichthyology - Otolith (sagitta) morphology is described in six tropical fish species belonged to different genera of the suborder Scorpaenoidei: Synanceia horrida, Inimicus sinensis,...     

Genetic diversity of charrs of the Commander Islands based on the analysis of mitochondrial DNA

Nucleotide sequences of the mitochondrial DNA cytochrome b (CytB) gene fragment and the control region (D-loop) of Dolly Varden (Salvelinus malma) from the Commander Islands and the Kol River of the Kamchatka Peninsula were examined. A high level of genetic variability of island populations comparable to that of the mainland population of western Kamchatka was demonstrated. The belonging of the Commander Islands chars to the genetic lineage of northern Dolly Varden Salvelinus malma malma was confirmed.     

Investigation of the helicon discharge plasma parameters in a hybrid RF plasma system

Results of an experimental study of the helicon discharge plasma parameters in a prototype of a hybrid RF plasma system equipped with a solenoidal antenna are described. It is shown that an increase in the external magnetic field leads to the formation of a plasma column and a shift of the maximum ion current along the discharge axis toward the bottom flange of the system. The shape of the plasma column can be controlled via varying the configuration of the magnetic field.     

Phyto- and Zooplankton of Open Overgrown Shallows of the Rybinsk Reservoir Adjacent to a Mixed Grey Heron–Great Egret (<Emphasis Type="Italic">Ardea cinerea</Emphasis> L. and <Emphasis Type="Italic">A. alba</Emphasis> L.) Colony at a High Water Level

Phyto- and zooplankton communities developing in the open overgrown shallows of the Rybinsk Reservoir under the influence of a bird colony are shown to lose specific traits of quantitative characteristics and structure fluctuation in response to the elevated water level in contrast to previous findings. Possible reasons, such as the decomposition of sunken coastal vegetation playing the main role, accompanied by the development of semiaquatic macrophytes and trophic relations between algae and invertebrates, are discussed. It is found that increased atmospheric precipitation leads to an increased abundance of Copepoda in the zooplankton. Presumably, this effect correlates with more rapid and intensive inflow of avian vitality products rich in nitrogen into the water, resulting in a change in the stoichiometric ratio of nitrogen and phosphorus in zooplankton food objects to values favorable for copepods.     

Winter Fish Distribution in the Riverbed Depression in the Urtysh River

Journal of Ichthyology - Winter fish distribution is investigated by means of computerized hydroacoustic complexes in the largest riverbed depression in the Irtysh. Fish aggregations whose...     

Specific characters of the mammoth calf (Mammuthus primigenius) from the Khroma River (Yakutia)

The exterior, skeletal morphology, and teeth of a 4- to 5-month-old woolly mammoth calf, Mammuthus primigenius Proboscidea, Elephantidae from the Khroma River (Yakutia, Russia) are described. This is the third and best preserved frozen carcass of the mammoth calves from Yakutia. The calf is male (penis available). The individual age as determined by the degree of wearing of DP2 and the beginning of wear of DP3 corresponds to the stage of transition to combined feeding (milk and vegetal forage). At the same time, formation of the cranial sutures (sutura sagittalis, fronto-temporalis, squamo-temporalis, and the suture between os occipitale superior and os occipitale inferior) testifies to an older juvenile stage. The proximal and distal epiphyses of the humerus and the distal epiphysis of the femur are represented by paired centers of ossification. A comparison of the dimensions of the head, body, and legs with the corresponding parameters of other M. primigenius calves of the same age shows the individual variability (10–15%) of these features. Although of medium size characteristic of M. primigenius calves, the described individual lacks subcutaneous fat deposits in the withers and subdermal areas of the body flanks. Death was caused by a rupture of the body and vertebral column at the level of the pectoral vertebrae 11–12. The deformation of the legs and longitudinal stretching of the soft tissues of the body caused no bone fractures (except for three ribs in the zone of the rupture). The long bones are not dislocated either in the shoulder and pelvic girdles or relative to each other. Possible causes and the timing of the death of the mammoth calves preserved in the permafrost are discussed.     

Specific fragmentation of T7 phage DNA at low-melting sites.

A method has been developed for selective fragmentation of T7 DNA at AT-rich regions. The molecules have been subjected to complete digestion with single-strand-specific SI endonuclease after fixation of DNA AT-rich regions in the denatured state by glyoxal. The treatment resulted in three fragments having molecular weights of 13.6 +/- 0.4, 8.2 +/- 0.4 and 3.5 +/- 0.16 megadaltons as determined by electron microscopy. The position of these fragments along the T7 DNA molecule has been determined by means of analysis of the intermediates during SI-cleavage.