Spatial avoidance of patches of polluted chernozem soils by soil invertebrates

Soil invertebrates and heavy metal concentrations are heterogeneously distributed in the soil of steppe plots surrounding an iron mining enterprise in southern Russia. This study assesses whether patches of high soil invertebrate abundance coincide with patches of low concentrations of pollutants. For this aim, spatial analysis by distance indices (SADIE) was applied. Three valleys in Belogorye Nature Reserve were chosen. One valley faced the tailing pond to the north and the other two faced south-east or south-west. Two sampling plots were chosen in each valley, 60 m apart from each other. On every plot 16 soil cores were collected from a grid of 4 × 4 units with a 5-m distance between each sample unit. Each soil core had an area of 76 cm² and was 12–15 cm deep. All macroinvertebrates were hand-sorted and identified to family. Abundance of soil invertebrates was not controlled by patches of metal concentration in the soil. Epigaeic groups, like insects and other invertebrates inhabiting the litter layer, were not directly associated with local parameters of the soil. On the contrary, belowground invertebrate abundance (elaterid larvae and earthworms) showed significant dissociation with some heavy metal (Fe, Pb, Zn) concentrations in the soil. The patchiness of soil pollution may act as a leading factor of belowground soil invertebrate distribution. The spatial structure of animal populations in industrially transformed soils needs further research.     

Rubrofugal influences on unit activity in the medial reticulospinal tract

Neurophysiology - The influence of the red nucleus on activity in various groups of fibers of the medial reticulospinal tract was investigated in cats anesthetized with chloralose and...     

Sorption immobilization of NAD-dependent enzyme systems. I. Influence of electrostatic interactions on the orientation of alcohol dehydrogenase on the sorbent surface

The model calculation of interactions between the horse liver alcoholdehydrogenase-globule and the charged surface of sorbents and electrodes was performed. It has been shown that due to the discrete distribution of charges the enzyme globula can sorb on the surfaces having the same sign of charge as the total globule charge. In case of alcoholdehydrogenase the anion sorption can occur at pH greater than pI. Also, the orientation and therefore the catalytic activity of the immobilized system can be optimal.     

Ion channnels and transporters in cancer. 5. Ion channels in control of cancer and cell apoptosis

Ion channels contribute to virtually all basic cellular processes, including such crucial ones for maintaining tissue homeostasis as proliferation, differentiation, and apoptosis. The involvement of ion channels in regulation of programmed cell death, or apoptosis, has been known for at least three decades based on observation that classical blockers of ion channels can influence cell death rates, prolonging or shortening cell survival. Identification of the central role of these channels in regulation of cell cycle and apoptosis as well as the recent discovery that the expression of ion channels is not limited solely to the plasma membrane, but may also include membranes of internal compartments, has led researchers to appreciate the pivotal role of ion channels plays in development of cancer. This review focuses on the aspects of programmed cell death influenced by various ion channels and how dysfunctions and misregulations of these channels may affect the development and progression of different cancers.     

A smoothed backbone-dependent rotamer library for proteins derived from adaptive kernel density estimates and regressions

Rotamer libraries are used in protein structure determination, prediction, and design. The backbone-dependent rotamer library consists of rotamer frequencies, mean dihedral angles, and variances as?a function of the backbone dihedral angles. Structure prediction and design methods that employ backbone flexibility would strongly benefit from smoothly varying probabilities and angles. A new version of the?backbone-dependent rotamer library has been developed using adaptive kernel density estimates for the rotamer frequencies and adaptive kernel regression for the mean dihedral angles and variances. This formulation allows for evaluation of the rotamer probabilities, mean angles, and variances as?a smooth and continuous function of phi and psi. Continuous probability density estimates for the nonrotameric degrees of freedom of amides, carboxylates, and aromatic side chains have been modeled as a function of the backbone dihedrals and rotamers of the remaining degrees of freedom. New backbone-dependent rotamer libraries at varying levels of smoothing are available from http://dunbrack.fccc.edu.     

<Emphasis Type="Italic">Aconitum</Emphasis> biotechnology: recent trends and emerging perspectives

The genus Aconitum (consists more than 250 species) is one of the most important clades of highly valued medicinal plants. Aconitum species are very essential in the traditional device of medication and feature excessive business demand in the herbal marketplace. Some of biologically energetic compounds, e.g., aconitine, indaconitine, pseudoacontine, and so on, had been recognized, and new formulations primarily based on those compounds are being produced as rapid rate. This has led to extensive and rather unregulated exploitation of the species in the wild making the genus a threatened group. Conventional breeding and propagation methods have contributed significantly, but these could not meet up with the ever increasing demands of herbal drug industry globally. Biotechnological interventions, therefore, emerge as an alternative approach in terms of higher production and conservation as well. In recent years, several reports have been published on in vitro propagation of various important Aconitum species. However, advanced biotechnological approaches, such as synthetic seed production and hairy root cultures, are still lacking with only a few reports available. The current review presents an updated overview and critical assessment of secondary data concerning the past and recent biotechnological approaches and interventions in genus Aconitum. This review also attempts to provide a detailed account of work explored so far in micropropagation and emphasizes over the areas not attempted yet, which will act as a baseline data as well as valuable information for different stakeholders and researchers working on various aspects of Aconitum biotechnology.     

Synaptic interaction between single motoneurons in the isolated frog spinal cord

The nature of synaptic interaction between two neighboring motoneurons in the isolated frog spinal cord was studied by parallel insertion of two separate micro-electrodes into the cells. In 82 of 89 motoneurons tested transmission through synapses between the motoneurons was electrical in nature, as shown by the absence or short duration of the latent period of elementary intermotoneuronal EPSPs, stability of their amplitude, and preservation of responses in Ca⁺⁺-free solution containing 2 mM Mn⁺⁺. Direct electrotonic interaction was demonstrated in both directions: artificial de- and hyperpolarization of one motoneuron led to corresponding shifts of membrane potential in the neighboring motoneuron. The time constant of rise and decay of this potential was appreciably greater than the time constant of the membrane of the two interconnected motoneurons. Blockade of the SD-component of the action potential in the "triggering" motoneuron led to a decrease in the elementary EPSP in the neighboring motoneuron. These facts suggest that electrotonic interaction takes place through dendro-dendritic junctions. Absence of rectification was demonstrated in electrical synapses between motoneurons. In four cases elementary EPSPs were chemical in nature, for they appeared 1.3–3.3 msec after the beginning of the action potential in the "triggering" motoneuron, and were blocked in Ca⁺⁺-free solution containing Mn⁺⁺; fluctuations of their amplitude approximated closely to a Poisson or binomial distribution. Such responses are evidently generated by synapses formed by recurrent axon collaterals of one motoneuron on the neighboring motoneurons. In three cases elementary intermotoneuronal EPSPs consisted of two components, the first electrical and the second chemical in nature. Morphological structures which may be responsible for generation of 2-component EPSPs are examined.Deceased.I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 16, No. 5, pp. 619–630, September–October, 1984.     

Sterol composition of nystatin-resistantCandida maltosa mutants

Composition of sterol fractions of nystatin-resistantCandida maltosa strains was determined. Using UV-spectrometry, TLC and GLC-MS it was demonstrated that resistance to nystatin is connected with the composition alterations of yeast cell sterols. Block of different stages of ergosterol biosynthesis was revealed in some mutants,viz. C-24-transmethylation, Δ⁸→Δ⁷, 14α-demethylation, C-5(6)-dehydrogenation, reduction of C-14(15) and C-24(28) double bonds.     

Evolution of neuronal systems of suprasegmental motor control

The study of supraspinal systems of motor control in a series of vertebrates by electroanatomical methods shows that certain key features of reticulo-motoneuronal projection persist throughout the scale of evolution from Cyclostomata to primates. There is a particularly marked similarity between the monosynaptic reticulo-motoneuronal EPSPs in primitive animals and in the advanced quadrupeds: amphibians, reptiles, and mammals. Certain general principles governing the maturation of derivatives of the reticulo-spinal system, namely the vestibulo-spinal and rubro-spinal projections, can be discussed. The most marked changes occurred in the development of the mammalian cortico-spinal system. The properties of the conducting system and synaptic connections with the spinal motoneurons differ considerably in the series rodents—carnivores—primates. In this survey the similarities and differences between the pyramidal and nonpyramidal monosynaptic projections to motoneurons in primates and the role of brain-stem structures in the mechanism of cortico-extrapyramidal control are discussed.I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Leningrad. Translated from Neirofiziologiya, Vol. 4, No. 5, pp. 453–470, September–October, 1972.