Molecular identification of filterable bacteria and archaea in the water of acidic lakes of northern Russia

Wetland ecosystems are the natural centers of freshwater formation in northern Russia lowland landscapes. The humic acidic waters formed in bogs feed the numerous lakes of the northern regions. One milliliter of the water in these lakes contains up to 10⁴ ultrasmall microbial cells that pass through “bacterial” filters with a pore size of 0.22 μm. The vast majority of these cells do not grow on nutrient media and cannot be identified by routine cultivation-based approaches. Their identification was performed by analysis of clone libraries obtained by PCR amplification of archaeal and bacterial 16S rRNA genes from the fraction of cells collected from water filtrates of acidic lakes. Most of the obtained bacterial 16S rRNA gene sequences represented the class Betaproteobacteria and exhibited the highest homology of (94–99%) with 16S rRNA genes of representatives of the genera Herbaspirillum, Herminiimonas, Curvibacter, and Burkholderia. The archaeal 16S rRNA gene clone library comprised genes of Euryarchaeota representatives. One-third of these genes exhibited 97–99% homology to the 16S rRNA genes of taxonomically described organisms of the orders Methanobacteriales and Methanosarcinales. The rest of the cloned archaeal 16S rRNA genes were only distantly related (71–74% homology) to those in all earlier characterized archaea.     

Status of the reproductive system of bony fish from the Teterev River and the Kiev Reservoir 20 years after the Chernobyl accident

The status of the reproductive system is investigated in five species of Teleostei from the Teterev River and the Kiev Reservoir (Ukraine), descendants of F₄2–F₇ generations of fish exposed to radiation from the accident at the Chernobyl nuclear power plant. Twenty years after the accident, a wide range of morphofuinctional anomalies of this system is present in fish. The most significant of them are: asymmetry and anomalous morphology of gonads, proliferation of connective tissue—sterilization, mass destruction of follicular and sex cells of various developmental stages, and hermaphroditism. Among the investigated species, disturbances of reproductive glands were preset to the highest extent in pike Esox lucius and crucian carp Carassius carassius. In the series of investigated generations the maximum frequency of occurrence of gonad anomalies was noted in F₄ and F₅, due to prolonged mutagenesis (Dubinin, 1986).     

A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Interconnection of physico-chemical characteristics of organic solvents and their denaturing ability in relation to proteins]

Reversible denaturation of several proteins (alpha-chymotrypsin, trypsin, laccase, chymotrypsinogen, cytochrome c and myoglobin) by a broad series of organic solvents of different nature was studied. The regularities of this process were analyzed, employing both experimental and literary data based on the results of kinetic and spectroscopic measurements. In all the systems under study denaturation proceeded in a threshold manner, i. e., an abrupt change in the catalytic and/or spectroscopic properties of the dissolved proteins was observed after a certain threshold concentration of the organic solvent had been reached. To account for the observed features of the denaturation process, a thermodynamic model of reversible protein denaturation by organic solvents was proposed. This model is based on the widely accepted viewpoint that the undisturbed water shell around the protein globule is necessary for maintaining the dissolved protein in the native state. Quantitative analysis of the model led to an equation establishing a relationship between the threshold concentration of an organic solvent and its physico-chemical characteristics, such as hydrophobicity, solvating ability and molecular geometry. This equation fits well in the experimental data for all the proteins tested. Based on the above thermodynamic model of protein denaturation, a novel quantitative parameter characterizing the denaturing strength of organic solvents (termed as the denaturation capacity or DC) was proposed. Different organic solvents arranged according to their DC values form the DC scale of organic solvents which permits to predict theoretically the threshold concentration of any organic solvent for a given protein.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lactate dehydrogenase isoenzyme spectrum in various areas of the reticular formation of the brain in rats: the effect of emotional stress

The changes in lactate dehydrogenase (LDG) isoenzyme content in the various brain areas were studied in intact Wistar rats and upon immobilization stress. LDG fraction levels were compared to BP changes during immobilization. The proportion of "anaerobic" LDG fractions was higher and the proportion of "aerobic" fractions lower in the dorsal area of midbrain substantia reticularis than in medulla oblongata reticular formation. The changes in LDG fraction content related to BP alterations during immobilization were observed in dorsal and ventral areas of midbrain (but not medulla oblongata) substantia reticularis. The proportion of anaerobic LDG4 fraction in the dorsal area of midbrain substantia reticularis was higher in rats with hypertensive responses, than in hypotensive animals. The changes in LDG5 fraction content were opposite. In the ventral area of midbrain reticular formation BP reduction was accompanied by a significant rise in "anaerobic" and a decrease in "aerobic" LDG fraction levels. The data obtained indicate certain differences in the intensity of aerobic and anaerobic processes of carbohydrate degeneration in various areas of substantia reticularis in control rats, as well as the correlation of changes in energy metabolism in the brain with BP alterations during emotional stress.     

Monoamine oxidase activity in rabbit brain nuclei in experimental acute emotional stress

Activity of monoamine oxidase in the neurons of catecholamine-synthesizing nuclei of hypothalamic and brainstem of rabbits with different resistance of cardiovascular functions to emotional stress was studied by the Glenner et al. method. An acute experimental emotional stress was induced by non-periodic electric stimulation of the hypothalamic ventromedial nucleus and the skin in immobilized adult chinchilla rabbits. It was found that monoamine oxidase activity in the neurons of groups A5, A6, A7 and A14 under acute experimental emotional stress increased in rabbits "resistant"to stress and remained unchanged in rabbits "predisposed" to stress. The activity of monoamine oxidase in the neurons of group A12 remained unchanged in the rabbits "resistant"to stress and decreased in the rabbit "predisposed" to stress.     

Denaturation capacity: a new quantitative criterion for selection of organic solvents as reaction media in biocatalysis.

The process of reversible denaturation of several proteins (alpha-chymotrypsin, trypsin, laccase, chymotrypsinogen, cytochrome c and myoglobin) by a broad series of organic solvents of different nature was investigated using both our own and literature data, based on the results of kinetic and spectroscopic measurements. In all systems studied, the denaturation proceeded in a threshold manner, i.e. an abrupt change in catalytic and/or spectroscopic properties of dissolved proteins was observed after a certain threshold concentration of the organic solvent had been reached. To account for the observed features of the denaturation process, a thermodynamic model of the reversible protein denaturation by organic solvents was developed, based on the widely accepted notion that an undisturbed water shell around the protein globule is a prerequisite for the retention of the native state of the protein. The quantitative treatment led to the equation relating the threshold concentration of the organic solvent with its physicochemical characteristics, such as hydrophobicity, solvating ability and molecular geometry. This equation described well the experimental data for all proteins tested. Based on the thermodynamic model of protein denaturation, a novel quantitative parameter characterizing the denaturing strength of organic solvents, called the denaturation capacity (DC), was suggested. Different organic solvents, arranged according to their DC values, form the DC scale of organic solvents which permits theoretical prediction of the threshold concentration of any organic solvent for a given protein. The validity of the DC scale for this kind of prediction was verified for all proteins tested and a large number of organic solvents. The experimental data for a few organic solvents, such as formamide and N-methylformamide, did not comply with equations describing the denaturation model. Such solvents form the group of so-called 'bad' solvents; reasons for the occurrence of 'bad' solvents are not yet clear. The DC scale was further extended to include also highly nonpolar solvents, in order to explain the well-known ability of enzymes to retain catalytic activity and stability in biphasic systems of the type water/water-immiscible organic solvent. It was quantitatively demonstrated that this ability is accounted for by the simple fact that nonpolar solvents are not sufficiently soluble in water to reach the inactivation threshold concentration.     

Stability of the cardiovascular functions of different genetic strains of rats subjected to emotional stress

The level of catecholamines was measured in various brain parts in rats of August and Wistar lines, characterized by different stability of cardio-vascular functions in emotional stress. In norm, the August line has a higher content of dopamine (DA), in the mid-brain in particular; the Wistar line has a higher content of noradrenaline (NA) in the hypothalamus. In susceptible animals, which showed different cardio-vascular disorders during 30 hours of immobilization (48% of the Wistar line and 90% of the August), and in animals resistent against emotional stress, the changes in the initial level of catecholamines were observed, both common and specific for two lines. An assumption is made that the stability of cardio-vascular functions in the emotional stress is provided for by an intensive metabolism of the NA-synthesizing neurones in the brain isthmus, and by a moderate activity of the DA-synthesizing neurones of the mid-brain; the susceptibility to cardio-vascular disorders in the emotional stress is due to increase in the activity of the DA-synthesizing mid-brain neurones, the decrease in the activity of the DA-hydroxilase and the exhaustion of NA in the hypothalamus.     

Identification and characteristics of plasmids of the strains of erythromycin-producing Streptomyces erythreus

Presence of plasmid DNA was investigated in laboratory strains 2 and 4 (NRRL 2338) of S. erythreus, as well as in strains 1 and 3 of S. erythreus subjected to improvement with respect to erythromycin production. Families of plasmids close by their molecular weights were identified in S. erythreus strains 3 and 4 (NRRL 2338). A plasmid DNA fraction of S. erythreus strain 3 was studied with electron microscopy. It enabled to identify 5 plasmids: pSE11, pSE12, pSE13, pSE14 and pSE15 with length of 5.3, 12.4, 16.3, 29.6 and 86.9 kb respectively. Using of various procedures for isolation of extrachromosomal DNA did not provide its detection in S. erythreus strains 1 and 2. At least a part of the plasmids detected in S. erythreus strains 3 and 4 (NRRL 2338) was conjugative. 32R-Labeled plasmid DNA of S. erythreus strain 3 was subjected to hydridization according to Sauthern with total DNA of the 4 strains treated with restrictases BamHI, PstI and BgIII. The studies showed that the genome of S. erythreus strain 2 was not homologous with the probe while S. erythreus strain 1 contained one of the plasmids or its part in chromosome-integrated state. In strains 3 and 4 (NRRL 2338) of S. erythreus certain plasmid DNAs were present in both autonomous and chromosome-inserted states. 32P-Labeled gene of erythromycin resistance (ermE) was subjected to hybridization according to Southern with total DNA of the 4 strains and with DNA plasmid fraction of S. erythreus strain 3. The signal was positive only in hydridization of the probe with total DNA of S. erythreus strains 1, 3, and 4 (NRRL 2338).(ABSTRACT TRUNCATED AT 250 WORDS)     

Cloning of the purA16 locus in Rec+ cells of Bacillus subtilis

A portion of purA16 chromosomal locus of Bacillus subtilis was cloned into Rec+ cells of this microorganism with pBD12 plasmid (carrying chloramphenicol and kanamycin resistance determinants) serving as a vector. The hybrid plasmids were stably maintained in cells grown on media supplemented with antibiotics and were lost from cells in the absence of drugs. The cloned fragment could incorporate into the chromosome some with a frequency of 10(-2) per cell per generation. A clone carrying the hybrid plasmid inserted into the chromosome was detected.