Igor V. Klimenkov

Specific Features of Mandible Structure and Elemental Composition in the Polyphagous Amphipod Acanthogammarus grewingkii Endemic to Lake Baikal

Background In crustaceans, several mechanisms provide for the mechanical strength of the cuticular “tools” (dactyli, claws, jaws), which serve to catch and crush food objects. Studies on the mandibles of the endemic Baikal amphipod Acanthogammarus grewingkii by means of electron microscopy and elemental analysis have revealed specific structural features of these mouthparts. Methodology The fine structure of the mandible has been studied by means of SEM, TEM, and AFM; methods used to analyze its elemental and phase composition include XEPMA, XPS, SEM-EDS analysis, and XRD. Conclusion Functional adaptations of the mandible in A. grewingkii provide for the optimum combination of mechanical hardness and fracture resistance, which is achieved due to a complex structure and composition of its cutting parts. Teeth of the mandible are covered by a thin layer of silica (10–20 µm). Their epicuticle is characterized by a high density, consists of three layers, and increases in thickness toward the tooth apex. The epicuticle is enriched with Br, while the concentrations of Ca and P reach the peak values in the softer internal tissues of the teeth. These data broaden the view of the diversity of adaptation mechanisms providing for the strengthening of cuticular “tools” in crustaceans.

Effect of selenium and arabinogalactan nanocomposite on viability of the phytopathogen Clavibacter michiganensis subsp. sepedonicus.

89 Anaerobic non sporulating bacteria of the genus Clavibacter, representing single or paired (or short chains of) non motile rods, are the most widespread and significant among phytopathogen Gram positive bacteria. Clavibacter michiganensis subsp. sepedonicus (Spieck. et Kotth.) Skapt et Burkh (C. michiganensis) causes potato ring rot; as the result of development of this disease, yield losses are as high as 10–45% [1, 2]. To date, effective prevention methods with C. michi ganensis are absent, and all the existing methods are preventive and restricted to the disinfection of con tainers, equipment, and planting material [3]. Very aggressive agents, such as formalin, hydrogen perox ide, and hydrochloric acid, are used as disinfecting substances [4].

Silver-containing nanocomposites with antioxidant activity based on humic substances of different origin

Humic substances isolated from curative mud, brown coal, and shale of the Mongolian deposits were used for the synthesis of water-soluble silver-containing nanocomposites. The humic substances from curative mud have the highest reducing and stabilizing ability among the studied objects. The compositions and structures of the obtained nanocomposites were characterized in detail by a complex of modern physicochemical methods. The humic substances and related nanocomposites were found to exhibit high antioxidant activity comparable with that of the known antioxidants.

Accumulation of petroleum hydrocarbons in intracellular lipid bodies of the freshwater diatom Synedra acus subsp. radians

The accumulation of hydrophobic compounds by phytoplankton plays a crucial role in the biogeochemical cycle of persistent organic pollutants (POPs) in aquatic environments. We studied the accumulation of polycyclic aromatic hydrocarbons (PAHs) in the freshwater diatom Synedra acus subsp. radians during its cultivation with crude oil hydrocarbons, using epifluorescent and laser confocal microscopy as well as gas chromatography–mass spectrometry (GC/MS) analysis. Our results revealed that in the presence of crude oil or an extract of a crude oil/n-hexane solution (light oil), S. acus subsp. radians accumulated PAHs in its lipid bodies. During cultivation in the presence of a crude oil/n-hexane solution, the cells selectively accumulated C12–C18 alkanes, with a preference for C15 and C16 homologues. The length of n-alkane hydrocarbon chains accumulated in cells was similar to the acyl chains of fatty acids of the diatom. We therefore suggest that the insertion of n-alkanes into the membrane lipid bilayer promotes the transmembrane transport of PAH in diatoms. Our results confirm the hypothesis that diatoms play a role in the elimination of hydrophobic hydrocarbons from aquatic systems.

Chiroplasmonic magnetic gold nanocomposites produced by one-step aqueous method using κ-carrageenan

Novel water-soluble chiroplasmonic nanobiocomposites with directly varied gold content were synthesized by a one-step redox method in water using a biocompatible polysaccharide κ-carrageenan (industrial product from algae) as both reducing and stabilizing matrix. The influence of the reactants ratio, temperature, and pH on the reaction was studied and the optimal reaction parameters were found. The structure and the properties of composite nanomaterials were examined in solid state and aqueous solutions by using complementary physical-chemical methods X-ray diffraction analysis, transmission electron microscopy, spectroscopy of electron paramagnetic resonance, atomic absorption and optical spectroscopy, polarimetry including optical rotatory dispersion with registration of interphase-crossbred Cotton effect of a chiral polysaccharide matrix on plasmonic chromophore of gold nanoparticles, dynamic and static light scattering. The new perspective multi-purpose nanocomposites demonstrate a complex of chiroplasmonic and magnetic properties, imparted by both nanoparticles and radicals enriched chiral polysaccharide matrix.

Morphofunctional peculiarities of erythrocytes in wild and farmed Coregonid fishes from Lake Baikal

Structure and cytometric indices of red blood cells (RBC) and hemoglobin content (Hb) and oxygen capacity of the blood (OCB) of omul, whitefish, and hybrids thereof captured in Lake Baikal (wild) and incubated and grown in a freshwater aquarium complex (FAC) (farmed) have been analyzed. Cytometric parameters of red blood cells of wild omul, whitefish, and hybrids thereof exceed those of the cells of fish reared in aquariums under identical conditions. The effect of aquarium rearing on the shape of red blood cells is the least pronounced in Siberian whitefish and F1 progeny of Siberian whitefish females and omul males (f Sw x m Om). The erythrocyte size in hybrids of female Lacustrine whitefish and male omul (f Lw x m Om) is determined by the size of these cells in female parents, since female Lacustrine whitefish have the largest erythrocytes. Cytometric parameters of erythrocytes of all Coregonid fishes investigated are higher in fish reared in warm aquaria than in conspecifics reared in aquaria with cold water. Erythrocyte nuclei are smaller in artificially propagated hybrids than in parent fish captured in the wild or in whitefish and omul reared in aquaria under the same conditions. A distinct pool of erythrocytes from whitefish captured in the wild have a 20–30% higher content of functionally active mitochondria than erythrocytes of whitefish reared in aquaria; a disrupted mitochondrial structure is also observed in erythrocytes from the latter population of fish. The results show that distinctive features of metabolism related to oxygen transport in the Baikal coregonid fish that were investigated are determined by adaptation to the conditions of the ecological niches occupied by the fish.

Blood cell structure in Baikal omul (Coregonus migratorius Georgi) and changes under phenol exposure

The main organ of myeloand erythropoiesis in Baikal omul (Coregonus migratorious Georgi) is the spleen and the main organ of lymphopoiesis is the kidney. Blast and maturing blood cells are also present in the tissues of the body kidney, gills, all sections of the gut, heart and liver. In this study, myelopoiesis was measured in omul after 1 h of phenol exposure (at concentrations of 3 and 6 mg L) and lymphopoiesis was measured after 1 day of phenol exposure (at concentrations of 3, 6 and 12 mg L). Myelopoiesis was inhibited at a phenol concentration of 12 mg L. Ultrastructural disorders occured in the blood cells as a result of toxicant effects and included vacuolisation of mitochondria and damage to mitochondrial cristae, destruction of endocellular structures, decrease in the number of ribosomes in the cytoplasm, fragmentation and vacuolisation of intracellular organelles, increase and swelling of the perinucleus space.

Rearrangement of Actin Microfilaments in the Development of Olfactory Receptor Cells in Fish

At present, it remains poorly understood how the olfactory neuron migrates through the thick neuroepithelium during its maturation from a stem cell and how it develops a specific sensitivity to environmental odorants after maturation. We investigated the cytochemical features associated with the development of olfactory cells before and after the incorporation of dendrites into the surface of the olfactory epithelium. Using cytochemical staining for the actin cytoskeleton and other cell components, we found that immature neurons acquire a streamlined shape that resembles a «hot-dog» during their migration: a dense layer of actin microfilaments forms beneath the surface membrane of the growing dendrite, and the bulk of the nuclear material moves inside this layer. We have found that when the cell makes contact with its environment, the dendritic terminal develops a wide actin layer, inside which a pore is formed. It is assumed that the functional receptors of odorants generate across this pore the first intracellular signal from environmental water-soluble odorants. These data illustrate the important role of the cytoskeleton in the differentiation of olfactory cells.

Synthesis of selenium and silver nanobiocomposites and their influence on phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus

Selenium and silver nanobiocomposites were synthesized based on potentially metabolizable for microbes polysaccharides arabinogalactan and starch, as well as based on humic compounds obtained from peloids (therapeutic muds) and brown coals of Mongolia. Their influence on the phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus was studied. The absence of a negative effect of nanocomposite precursors (arabinogalactan, starch, and humic compounds) on the bacterial growth was demonstrated. All the nanocomposites studied were found to reduce the bacterial growth. Vital dyes were used to reveal that after 24 h of incubation, the examined nanobiocomposites caused changes in the morphology of the cells: the bacteria grew shorter and thicker, which led to their death. The nanoselenium composite in starch and the nanosilver composite in humic substances possessed the greatest effects. The results obtained indicate the presence of bacteriostatic and bactericidal effects in a number of nanocomposites studied.

Optical Absorption Evolution of Silver Nanocomposites with Arabinogalactan-g-Oligopyrrole Copolymer Matrix

Anna V. Zhmurova∗ Irkutsk State University of Railways, Chernyshevskogo 15, Irkutsk, 664074, Russia Leo E. Zelenkov†, Boris G. Sukhov‡ A.E. Favorsky Irkutsk Institute of Chemistry SB RAS Favorsky 1, Irkutsk, 664033, Russia Anatoliy I. Illarionov§ Irkutsk National Research Technical University, Lermontova 83, Irkutsk, 664074, Russia Roman Y. Shendrik¶, Evgeniy A. Radzhabov A.P.Vinogradov Institute of Geochemistry, SB RAS, Favorsky 1a, Irkutsk, 664033, Russia Igor V. Klimenkov∥ Limnological Institute, SB RAS, Ulan-Batorskaya 3, Irkutsk, 664033, Russia Anatoliy N. Sapozhnikov, Boris A.Trofimov A.P.Vinogradov Institute of Geochemistry, SB RAS, Favorsky 1a, Irkutsk, 664033,Russia