SC-karyotyping on electronic microscopy (EM) analysis of synaptonemal complexes (SC) spermocytes of silver fox (Vulpes fulvus)

We present an electronic microscopy (EM) analysis of synaptonemal complexes (SC) spermatocytes of male silver fox Vulpes fulvus at the pachytene stage. The SC-karyotypes of pachetene cells were made and described. Knowledge of normal SC-karyotype is necessary to reveal synaptic abnormalities of autosome and sex bivalents during the pachytene. It was indicated that EM analysis of SC-spermatocytes—the study of synaptonemal complexes in agricultural animals—is a very good instrument for comparative analysis of normal SC-karyotype of foxes that carry chromosomal abnormalities and in fur-bearing animals as well.     

Characteristics of the first meiotic division in hamster hybrids obtained by backcrossing Phodopus sungorus and Phodopus campbelli]

Spermatocytes of fertile, subfertile, and sterile hamster hybrids obtained by backcrossing Phodopus sungorus and Ph. campbelli were analyzed under light and electron microscopes. Light microscopy showed that early meiosis was blocked in pachitene in the spermatocytes of sterile hybrids. The X and Y chromosomes were dissociated in metaphase I in several fertile and subfertile animals. Electron microscopic analysis of the synaptonemal complex (SC) revealed a disturbed synapsis of sex chromosomes and autosomes in all hybrids. Dissociation of the sex chromosomes, terminal and interstitial asynapsis, and interlocking of autosomes were observed. Disturbed synapsis in hybrids was assumed to result from the difference between Ph. sungorus and Ph. campbelli in not only their chromosomes, but their genes as well.     

Priming effect of calcium ionophores on phorbol ester-induced respiratory burst in mouse peritoneal neutrophils.

The abilities of three calcium ionophores (A23187, 4-bromo-A23187, and ionomycin) to modulate the respiratory burst of neutrophils induced by phorbol ester and to increase the concentration of free intracellular Ca2+ ([Ca2+]i) were compared. The production of reactive oxygen species (ROS) was determined by luminol-dependent chemiluminescence and [Ca2+]i was determined with the Fura-2 fluorescent probe. A23187 (0.05-2 microM) and ionomycin (0.001-0.5 microM) but not 4-bromo-A23187 amplified 3-4-fold the respiratory burst induced by phorbol ester. The integral response (total production of ROS over 6 min) had a bell-shaped dependence on the concentration of ionomycin and A23187 with increase and decrease at low and high concentrations of the ionophores, respectively. The maximal effect was found at 0.5 microM ionomycin and 2 microM A23187, these concentrations resulting in transient increases in [Ca2+]i to 1776 +/- 197 and 955 +/- 27 nM, respectively. The ionophores had no effect in calcium-free media, though they increased [Ca2+]i to approximately 400 nM through the mobilization of intracellular Ca2+. In cells with exhausted stores of Ca2+, the addition of 1.5 mM Ca2+ combined with phorbol ester amplified twofold the production of ROS. The inhibition of phospholipase A2 with 4-bromophenacyl bromide significantly decreased the production of ROS. Thus, the entrance of Ca2+ and generation of arachidonic acid under the influence of phospholipase A2 are necessary for the ionophore-induced priming of production of ROS during cell activation with phorbol esters.     

Action of a nonhydrolyzable guanosine triphosphate analog on modulation of calcium current by dopamine in Lymnaea stagnalis neuron

Dependence of the blocking effect of dopamine on the calcium current on guanosine triphosphate (GTP) was investigated on dialyzed neurons ofLymnaea stagnalis. Against the background of the effect of the nonhydrolyzable GTP analog guanosine-5-0-3-thiotriphosphate (GTPS) (10^–4 M) marked residual blocking of the calcium current was observed during rinsing out of dopamine, and this was potentiated in the case of repeated application of the hormone. It is suggested that the receptor-mediated effect of GTPS on the calcium current is effected through activation of phospholipase C.Institute of Biophysics, Academy of Sciences of the USSR, Pushchino, Moscow. Translated from Neirofiziologiya, Vol. 23, No. 1, pp. 43–48, January–February, 1991.     

Interactions between plants and associated bacteria in soils contaminated with heavy metals

Interactions were studied between oat (Avena sativa) and two bacterial species, Bacillus subtilis and Pantoea agglomerans, in soils contaminated with heavy metals (HM), cadmium (50 mg/kg), and lead (200 mg/kg). Exposure to HM resulted in decreased (by 30–50%) length, mass, and ratio of shoot to root dimensions. Inoculation with bacteria lead to restoration and further enhancement of plant productivity, raising it above the level achieved via inoculation of oat in uncontaminated soils. It also reduced HM accumulation by plants. Pure cultures of P. agglomerans accumulate HM more intensively than those of B. subtilis (adsorbing activity was studied for both cells and extracellular metabolites). After the introduction of bacteria, lead, and cadmium content in soil decreased four- to fivefold and two- to threefold, respectively. Protection from HM is attributable to reorganizations in the populations of root-associated bacteria: cell number increases in the rhizoplane while decreasing in the rhizosphere.     

Embryonal effects of <Emphasis Type="Italic">t</Emphasis>-haplotypes in mice

The effects of t-haplotypes on embryonic morphology in house mouse Mus musculus were described. Lethal mutations, t-haplotypes, in homozygotes induce abnormal embryogenesis and zygotic death at different developmental stages, which depends on the time of their action in ontogeny. Death commonly occurs in the first semester of pregnancy from the morula to the mature embryo stage (day 9–10), and the embryogenetic abnormalities and their timing were Specific for each t-haplotype. Such mutations were analyzed to identify the gene products (proteins) affecting the nervous system development. The t-complex proved to contain tandem repeats coding for regulatory factors modulating the expression of specific structural genes in mouse neurons.     

Effect of detonation nanodiamonds on phagocyte activity

Detonation ND (nanodiamond) holds much promise for biological studies and medical applications. Properties like size of particles, inclination for modification of their surface and unambiguous biocompatibility are crucial. Of prime importance is interaction between ND and immune cells, which supervise foreign intrusion into an organism and eliminate it. Neutrophils are more reactive in inflammatory response implementing cytotoxical arsenal including ROS (reactive oxygen species). The aim of the work was to estimate the ability of two ND samples (produced by Diamond Center and PlasmaChem) to keep the vitality of neutrophils from the inflammatory site. The ability of cells to generate ROS in the presence of ND particles is considered as indicating their biocompatibility. IR spectra and size of particles in the samples were characterized. Acid modification of ND was carried out to get the luminescent form. In the biological aspect, ND demonstrated up or down action, depending on the concentration, time and conditions of activation of cells. Weak action of ND in whole blood was obtained possibly owing to the ND adsorbed plasma proteins, which mask active functional groups to interact with the cell membrane. ND did not influence the viability of isolated inflammatory neutrophils in low and moderate concentrations and suppressed it in high concentrations (≥1 g/l). Addition of ND to the cell suspension initiated concentration-dependent reaction to produce ROS similar to respiratory burst. ND up-regulated response to bacterial formylpeptide, but up- and down-modified (low or high concentrations, accordingly) response to such bacterial agents as OZ (opsonized zymosan), which neutrophils swallow up by oxygen-dependent phagocytosis. Localization of the particles on the cell surface as into the cells was identified by monitoring the intrinsic fluorescence of oxidized ND. The various mechanisms that could account for penetration of ND particles into the cell are discussed. Common conclusion concerns compatibility of ND with living neutrophils from inflammatory site and their normal functioning for infection safeguard.     

Relationships between pasture legumes, rhizobacteria and nodule bacteria in heavy metal polluted mine waste of SW Sardinia

Local populations of the pasture legumes Astragalus hamosus, Lotus edulis, Lotus ornithopodioides, Medicago ciliaris and Scorpiurus muricatus from heavy metal polluted and unpolluted sites in Sardinia were compared for tolerance to Zn, Cd and Pb in hydroponics. Tolerance of plants to heavy metals varied significantly depending on the species, origin of the population and metal. The species L. edulis, L. ornithopodioides and M. ciliaris possessed higher metal tolerance and were used in a pot experiment with Zn, Cd and Pb polluted mine waste. Seeds were inoculated with the metal tolerant plant growth-promoting rhizobacterium Variovorax paradoxus 5C-2 or/and with the corresponding symbiotic nodule bacteria containing the enzyme 1-aminocyclopropane-1-carboxylate deaminase. Co-inoculation with the bacteria had synergistic and additive effects on nodule number, root growth and uptake of elements (N, P, Ca, Mg, Na, Mn, Zn and Pb) in shoots of L. edulis and L. ornithopodioides. Shoot biomass and uptake of K, Fe and Cd was increased by a combined inoculation of L. edulis. The ratio between shoot and root contents of Pb in L. ornithopodioides was above 1, suggesting a characteristic trait of hyperaccumulating species. The results suggest that the development of metal tolerant and efficient plant-bacteria systems might be useful for phytostabilization and revegetation of mine wastes.     

Genetic characterization of wild leguminous nodular bacteria living in the South Urals

Genetic diversity and phylogeny of rhizobia that nodulate 18 species of wild-growing bean plants of South Urals from 8 genera belonging to 4 tribes (Loteae, Genisteae, Galegeaev and Hedysareae) was studied. It was demonstrated that for the wild-growing plants of Galegeae and Hedysareae tribes symbiotic interaction with various strains of nodule bacteria that closely related to bacteria of Mesorhizobium sp. was typical of the plants of Genisteae tribe--to bacteria of Bradyrhizobium sp. In the nodules of Lortus ucrainicus from Loteae tribe we have found a rhizobium that is closely related to the bacteria of Mesorhizobium sp., and at Coronilla varia rhizobia strains obtained by us were close by sequence of a 16S pRNA gene to Rhizobium sp. In the nodules of some kinds of the investigated plants we found also minor species of a rhizobia, which structure is under the great influence of conditions of the host plant growth.