Action of dehydration on the survival, morphology and ultrastructure of the conidia of air-borne and culture collection strains of Aspergillus niger and Penicillium chrysogenum

The effect of dehydration on the morphology and fine structure of conidia was studied with the atmospheric and collection strains of Aspergillus niger and Penicillium chrysogenum. Dehydration did not cause changes in the structure of most conidia. However, destructive changes in the conidial wall and membrane were found in some conidia. The cytological changes of conidia were either reversible or irreversible, which determined their survival rate during dehydration.     

Behavior of Rats in the Open Field within the Early Period after Light-Degree Blast-Induced Neurotrauma

Neurophysiology - Blast-induced neurotrauma (BINT) is a specific type of traumatic brain injury (TBI). At present, this type of injury is rather widespread throughout the world due to its...     

Detection of <Emphasis Type="Italic">Borrelia miyamotoi</Emphasis> in <Emphasis Type="Italic">Ixodes persulcatus</Emphasis> ticks in Russia

Unfed adult ticks Ixodes persulcatus from five regions of Russia were examined by PCR method in order to analyze distribution and diversity of B. miyamotoi. B. miyamotoi DNA was found in 1.8, 2.9, 4.5, 2.3, and 2.5% of ticks from Leningrad, Sverdlovsk, Novosibirsk, and Irkutsk provinces, and from Khabarovsk Territory, respectively. Molecular typing of B. miyamotoi DNA was based on the partial sequencing of the 16S rRNA, p66, and glpQ genes. A single genetic variant of B. miyamotoi was detected in all the samples of ticks collected from five regions.     

Biochemical and photochemical degradation of the herbicide lontrel

Degradation of Lontrel by activated sludge (AS) of purification works and UV irradiation was studied. 3,6-Dichloropicolinic acid (3,6-DCPA, the main active principle of Lontrel) was not degraded by the microbial association of the AS. AS treated with nitrosourea under various conditions did not oxidize Lontrel either. Hard UV radiation degraded 3,6-DCPA within 4-24 h at constant sparging (bubbling) of air, oxygen, or ozone. The rate of oxidation with oxygen or ozone bubbling was three to four times higher than with air bubbling. It was found that the products of photochemical degradation of Lontrel were also toxic; however, they were readily degraded by AS microorganisms without additional AS treatment.     

Karyological evidence for meiosis in the three different types of life cycles existing in Agaricus bisporus

In Agaricus bisporus all cytological studies performed until now concerned the pseudohomothallic and bisporic var. bisporus. In the past 12 y two tetrasporic varieties have been described, the heterothallic var. burnettii and the homothallic var. eurotetrasporus. Our aim was to compare the behavior of the nuclei in the vegetative and reproductive cells of the three varieties with light microscopy (Feulgen and DAPI staining) and transmission electron microscopy. Most of the vegetative cells contained 3-5 nuclei in the three varieties. Nuclear migrations through the septum were detected. In the basidia relative locations of nuclei and vacuoles, meiotic spindle alignments, relative content of nuclear DNA and synaptonemal complexes were measured or observed. From the observation of numerous asynchronous second division of meiosis within basidia of var. bisporus and var. burnettii a new hypothesis emerges to explain the nonrandom distribution of the four meiotic products in the two spores of the bisporic basidia. Karyogamy and meiosis similarly occurred in the three varieties. In the case of A. bisporus var. eurotetrasporus this implies that the reproductive mode is sexual and therefore homothallic in the strict sense. The three different types of life cycles are described.     

Changes in physicochemical properties of proteins, caused by modification with alkylhydroxybenzenes

Kinetic characteristics of model enzymes and physicochemical properties of globular proteins modified by chemical analogues of low-molecular-weight microbial autoregulators (alkylhydroxybenzenes, AHBs) have been studied. C₇ and C₁₂ AHB homologues were used, differing in the length of the alkyl radical and the capacity for weak physicochemical interactions. Both homologues affected the degree of protein swelling, viscosity, and the degree of hydrophobicity. The effects depended on the structure of AHBs, their concentration, and pH of the solution, which likely reflects changes in the charge of the protein globule and its solvate cover. Variations of hydrophobicity indices of AHB-modified enzymes (trypsin and lysozyme) were coupled to changes in the catalytic activity. The values of K _M, measured for the enzymes within both AHB complexes, did not change, whereas V _max increased (in the case of C₇ complexes) or decreased (C₁₂ complexes). Possible molecular mechanisms of changes in the physicochemical and catalytic parameters of enzymatically active proteins, induced by modification with structurally distinct AHBs, are described, with emphasis on targeted regulation of functional activity.     

Results of experimental radiobiological studies made within the 10-kilometer zone of the Chernobyl AES accident]

A study was made of the effect of high radioactive contamination on the animal organism (C57BL/6 mice) and HeLa cell culture within the ten-kilometer zone of the Chernobyl A.P.S. accident. The total radiation dose, as calculated by a gamma-component, was 0.09 to 2 Gy. A long-term exposure of mice within the zone (cumulative dose of 1.8 to 2 Gy) caused a significant decrease in bone marrow stem potencies and changes in the brain vascular system; subsequent acute exposure of animals increased interferon titres in the serum to a much greater extent than a single acute exposure did. As to HeLa cells, irradiation there of with doses of 0.09 to 0.4 Gy during 15-20 postirradiation generations caused a decrease in the proliferative activity, an emergence of cells with micronuclei and of giant cells, and remote cell death.     

Analysis of EEG Structural Synchrony in Adolescents with Schizophrenic Disorders

A total of 39 healthy adolescents and 45 adolescents with schizophrenic disorders (mean age 12.3 years) were examined to study the EEG structural synchrony as reflecting temporal synchronization of the operational activity of neuronal networks. A significant decrease in the EEG structural synchrony was observed in the adolescents with schizophrenic disorders as compared to the healthy adolescents. The decrease was detected predominantly in the interhemispheric pairs of EEG derivations, as well as in the pairs related to the frontal, temporal (predominantly on the left), and right parietocentral regions. The findings provide evidence in favor of Friston’s hypothesis of disintegration of cortical electrical activity in schizophrenia and extend the hypothesis in that it is the operational synchrony of cortical activity that might suffer first in schizophrenia.__________Translated from Fiziologiya Cheloveka, Vol. 31, No. 3, 2005, pp. 16–23.Original Russian Text Copyright © 2005 by Borisov, Kaplan, Gorbachevskaya, Kozlova.