External structure of postorbital organ of certain representatives of family astronesthidae (Stomiiformes)

The external structure of postorbital organ is described in detail in seven representatives of family Astronesthidae, i.e., Borostomias elucens, B. panamensis, B. mononema, B. antarcticus, Heterophorus ophistoma, Neonesthes microcephalus, and Rhadinesthes decimus. The shape, sizes, position with respect to eye, and some other features of the structure of the postorbital organ are characteristic of the species or close species. The comparison of the structure of this organ in the above-mentioned representatives of the family Astronesthidae and earlier studied species of genus Astronesthes is given.     

Polymorphism of the myogens locus in some representatives of sturgeons (Acipenseridae)

This study investigates muscle proteins in Russian (Acipenser gueldensiaedtii Brandt), Siberian (Acipenser baerii Brandt), and Amur (Acipenser schrenckii Brandt) sturgeons using the method of polyacrylamide gel electrophoresis. A group of fractions, which is presumably the product of a polyallelic duplicated MY-1* locus, is recorded among the general pool of proteins. Data from densitometric analysis makes it possible to put forward a hypothesis about an eight-gene determination of this system of proteins. The highest heterogeneity and polymorphism was revealed in the Russian sturgeon. Analysis of the genotype distribution in samples of the studied species allowed us to make an assumption that the genetic structure of spawning sturgeon stocks is significantly metamorphosed under the influence of anthropogenic and natural factors.     

Materials for Revision of the Genus Photonectes (Melanostomiidae)

Journal of Ichthyology - Characters of external morphology of Melanostomiidae fishes of genus Photonectes are critically analyzed. The features previously used to distinguish the subgenera are...     

New Species of Eustomias from the Waters of Madagascar (Melanostomiidae)

Journal of Ichthyology - Eustomias zygolampas sp. n. is described from the western Indian Ocean; it is characterized by the specific structure of the chin barbel. The new species belongs to the...     

Isoprenoid pigments in representatives of the family Microbacteriaceae

By using fosmidomycin and mevinolin (inhibitors of the synthesis of isoprenoid pigments), spectrophotometry, and mass spectrometry, the presence of isoprenoid pigments is shown in 71 of the 78 strains under study. All of these strains belong to 11 genera of the family Microbacteriaceae. Yellow, orange, and red pigments are found to have absorption spectra typical of C40-carotenoids. Eight out of the sixteen strains of the genus Microbacterium are able to synthesize neurosporene, a precursor of lycopene and beta-carotene. The biosynthesis of carotenoids in some representatives of the genera Agromyces, Leifsonia, and Microbacterium is induced by light. Inhibition of the biosynthesis of isoprenoid pigments by fosmidomycin suggests that they are synthesized via the nonmevalonate pathway. Twelve strains are found to exhibit both the nonmevalonate and mevalonate pathways of isoprenoid synthesis. These data, together with the difference in the inhibitory concentration of fosmidomycin, can be used for differentiating various taxa within the family Microbacteriaceae.     

Fossil representatives of the family Greenideidae (Hemiptera, Aphidoidea) from the Miocene of Europe

Four new aphid species (Hemiptera, Aphidoidea, Greenideidae) are described on the basis of imprints in oil-shales from the Miocene of Europe (Rubielos de Mora, Spain; Vishnevaya Balka ?Stavropol?, Russia): Eutrichosiphum europaeum nov. sp., Greenidea hispanica nov. sp., Greenideoida (Pentatrichosiphum) turolensis nov. sp. and Mollitrichosiphum rubusensis nov. sp. All the taxa are placed within recent genera of the subfamily Greenideinae. Miocene representatives of this subfamily have been found in the south of Europe. Later changes of climatic conditions limited its geographic range to south-eastern Asia, where it is now represented by over 130 species of seven genera.     

New representatives of the family Melagathiceratidae (Ammonoidea) from the Lower Triassic of South Primorye

A new ammonoid genus, Ussurijuvenites (Melagathiceratidae), is described from the early Olenekian of South Primorye, represented by two new species (U. popovi sp. nov. and U. artyomensis sp. nov.); data on the inner shell structure of melagathiceratid ammonoids (based on U. artyomensis sp. nov.) are presented for the first time.     

Floral elaiophore structure in four representatives of the Ornithocephalus clade (Orchidaceae: Oncidiinae)

Background and Aims A significant number of species assigned to the Neotropical orchid sub-tribe Oncidiinae reward insect pollinators with oil produced in floral glands termed elaiophores. The latter may be glabrous (epithelial elaiophores) or hirsute (trichomal elaiophores). Although the detailed anatomy and ultrastructure of epithelial elaiophores have been studied for a number of genera, such as Oncidium Sw., Gomesa R. Br. and Trichocentrum Poepp. & Endl., hitherto, trichomal elaiophores have been investigated only for a single species of Oncidiinae, Ornithocephalus ciliatus Lindl. Furthermore, this is the only representative of the Ornithocephalus clade to be investigated to date. Here, an examination is made of the elaiophore anatomy and ultrastructure of a further four species currently assigned to this clade (Ornithocephalus gladiatus Hook., Phymatidium falcifolium Lindl., Zygostates grandiflora (Lindl.) Mansf. and Zygostates lunata Lindl.) and the results compared with those obtained for other Oncidiinae. Methods Elaiophore structure was examined for all species at three stages of flower development: closed bud, first day of anthesis and final stage of anthesis, using light microscopy, fluorescence microscopy, scanning electron microscopy, transmission electron microscopy and histochemistry. Key Results Elaiophores of O. gladiatus occur upon the lateral lobes of the labellum and display characters intermediate between those of typical epithelial and trichomal elaiophores, in that they are largely glabrous, consisting mainly of cuboidal epidermal cells, but bear short, unicellular hairs proximally. By contrast, the elaiophores of all the other species investigated occur on the callus and are of the trichomal type. In P. falcifolium, these unicellular hairs are capitate. In all species, oil secretion commenced at the closed floral bud stage. Ultrastructurally, the mainly trichomal elaiophores of the four representatives of the Ornithocephalus clade closely resembled the epithelial elaiophores of other Oncidiinae, in that their cells displayed an organelle complement typical of lipid-secreting cells. However, in some taxa, a number of noteworthy characters were present. For example, the elaiophore cuticle of O. gladiatus and P. falcifolium was bi-layered, the outer layer being lamellate, the inner reticulate. The cuticle of Z. grandiflora and Z. lunata was also lamellate, but here, a reticulate layer was absent. Accumulation of secreted oil resulted in the localized distension of the cuticle. Cuticular cracks and pores, however, were absent from all species. The walls of the secretory cells of Z. grandiflora were also atypical in that they had short protuberances or ingrowths, and contained cavities which are thought to be involved in the secretory process. Conclusions Of the species investigated, most displayed similar anatomical organization, their trichomal elaiophores occurring on the labellar callus. They, thus, differ from many other members of the Oncidiinae, where epithelial elaiophores are found either on the callus, or on the lateral lobes of the labellum. However, ultrastructurally, all elaiophores, whether those of representatives of the Ornithocephalus clade, or those of other oil-secreting Oncidiinae, possessed a similar complement of organelles, regardless of whether the elaiophores were trichomal or epithelial. In view of the latter, and the similar chemical composition of oils derived from all Oncidiinae investigated to date, it is probable that position and type of elaiophore, and possibly the structure of the overlying cuticle, play an important role in pollinator selection in these oil-secreting orchids.     

Peculiarities of secondary structure of serum albumin of some representatives of the animal kingdom

Methods of infrared (IR) spectroscopy and circular dichroism (CD) are suitable techniques for detection of proteins structural changes. These methods were used for determinating peculiarities of the secondary structure of serum albumins in some representatives of two classes of reptiles: Horsfield's tortoise (Testudo horsfieldi), water snake (Natrix tessellata) and grass snake (Natrix natrix) and birds: domestic goose (Anser anser), domestic chicken (Gallus domesticus), domestic duck (Anas platyrhyncha) and dove colored (Columba livia). An analysis of IR spectra and spectra obtained by the method of CD of serum albumins of both classes representatives revealed that beta-folding structure and alpha-helical sections that form the alpha-conformation play an important role in conformational structure formation of polypeptide chain and also disordered sites of molecules of these proteins. It was observed that certain redistribution depending on animals species exists, in the formation of secondary structure of serum albumins of the investigated representatives of reptiles and birds classes between the content of beta-folding structure, alpha-helical sections and disordered sites in molecules of these proteins.     

Molecular phylogenetic perspective on the evolution of the deep-sea fish genusCyclothone (Stomiiformes: Gonostomatidae)

A portion of mitochondrially encoded 12S and 16S ribosomal RNA genes were sequenced from 13 currently recognized species of the midwater deep-sea fish genusCyclothone (Stomiiformes: Gonostomatidae) and three gonostomatid outgroup taxa. Phylogenetic analyses using maximum parsimony and maximum likelihood methods were performed on unambiguously aligned, combined sequences (803 bp) of the two genes. The resultant tree topologies from the two methods were congruent, being robust and supported by various tree statistics, enabling the evolutionary history ofCyclothone to be described in detail. The molecular phylogeny demonstrated striking inconsistencies with previously proposed “natural groups”, although the latter could be confidently refuted by the molecular data. The most significant characteristic of the evolutionary history ofCyclothone was the independent acquisition of an apomorphic depth habitat from the relatively ancestral, lower mesopelagic habitat, by each of three major distinct lineages that had diverged earlier in their evolution. Moreover, such macroevolutionary habitat shifts had been necessarily accompanied by morphological and ecological novelties, presumably originating from paedomorphosis. Repeated evolution of such changes strongly suggests ontogenetic plasticity inCyclothone which could enable these fishes to acquire larval-like, simple organization of body structure. Such a body plan could help them subsist in food-poor surroundings and regulate reproductive variables that take advantage of increasing larval survival toward shallower depths. Recent speciation events, on the contrary, have produced contemporary sister species of allopatric (or microallopatric) distributions, but few morphological and ecological differences. Even if remarkable miniaturization has occurred, such as in the Mediterranean endemicC. pygmaea, it had to have been a simple truncation of ancestral species' ontogeny without attendance of any discernible paedomorphic features. On the basis of the fossil record, geological history of the Mediterranean region, and ectotherm molecular divergence rate, it was estimated thatCyclothone radiation had already started in the early-middle Miocene (17–20 million years ago).     

Discovery of Photonectes uncinatus on the Walvis Ridge (Southeast Atlantic) and Species Redescription (Melanostomiidae)

Journal of Ichthyology - The second specimen of the rare species Photonectes uncinatus, previously known only by the holotype from the Rio Grande Rise (Southwest Atlantic), was discovered in the...     

External morphology and phylogenetic significance of the dorsal/neck organ in the Conchostraca and the head pores of the cladoceran family Chydoridae (Crustacea, Branchiopoda)

On basis of a SEM study the homology between the neck/dorsal organ of the Conchostraca and the head pores of the cladoceran family Chydoridae is established. Species of Lynceus (Conchostraca) and Eurycercus (Chydorinae) show a characteristical similar arrangement of four elevated areas within a circular/oval organ. Presence of two lateral pores may be an apomorphy for the Chydoridae lost in the Chydorinae and in some other genera. Some species of the Chydoridae (Rhynchotalona falcta and Tretocephala ambigua) display what can be interpreted as intermediate stages between the circular/oval organs in Eurycerus and more aberrant neck organ structures in the remaining Chydoridae. A characteristic neck organ morphology — two widely separated median pores with two smaller pores in between and without lateral pores — is considered as a synapomopphy for the Chydorinae. In contrast, no component of the neck organ morphology could be given synapomorphic status for all the species of the Aloninae. A number of potential apomorphies, related to the neck organ, seem to place subgroups of the Aloninae closer to the Chydorinae than to the rest of the subfamily. These apomorphies include, among others, elongation of the neck organr after Eurycercus has been branched off and subdivision of the neck organ into discrete pores after Rhynchotalona and Tretocephala has been branched off. If this interpretation is correct it will leave the Aloninae paraphyletic with respect to the Chydorinae.     

Energy metabolism of some representatives of the Haemophilus group

The purpose of this investigation was to characterize the carbohydrate catabolism and the constellation of the respiratory chain components of Haemophilus influenzae RAMC 18 Bensted, H. parainfluenzae 1 Fleming, H. parainfluenzae 429 Pittman and H. aegyptius 180a Pittman. These strains represent several physiological types with respect to respiratory quinones and glucose catabolism.On addition of glucose or lactate to the complex growth medium a remarkable increase in cell mass was observed. Depending on the growth rate, carbohydrate degradation varied with the strains examined so that at the end of the exponential growth phase only small amounts of the supplements could be demonstrated.All strains were found to possess functional enzymes of Embden-Meyerhof-Parnas-, Entner-Doudoroff-pathways, hexosemonophosphate shunt, tricarboxylic acid cycle and gluconeogenesis with an extremely high activity of malate dehydrogenase.The concentration of cytochromes varied according to culture conditions. The cytochromes a₁, d, o and b+c were found to occur under aerobic conditions. In cells grown anaerobically in the presence of fumarate cytochromes a₁ and d could not be demonstrated. Under aerobic conditions preparations of H. parainfluenzae 1 Fleming exhibited an -maximum at 558 nm, whereas under anaerobic culture conditions with fumarate as terminal electron acceptor an -maximum at 552 nm occurred, suggesting different roles of b and c type cytochromes in aerobic and anaerobic electron transport to fumarate, respectively.