An analysis of the work and tasks of the microbiology laboratory at a multidisciplinary research institute

The comparative analysis of the work of 3 groups of microbiologists at a multiple-discipline clinical research institute has permitted the development of the method for the evaluation of the work of researchers in the microbiological laboratory. The volume of investigations carried out in the laboratory, the relative significance of individual samples of clinical material, the degree of contamination of the samples under study, the level of the identification of microbes and the analysis of the data obtained in the course of investigations have been used as evaluation criteria. The method may be used for the objective quantitative evaluation of the work and the level of professional training of individual researchers, as well as for the calculation of expenditures in materials and time, necessary for performing investigations. According to the data of the analysis carried out by the authors with the use of the proposed method, the work of scientific-practical groups at the institutions of this category holds the greatest promise.     

Cell apoptosis in the culture: specific features of manifestation and influence on the effectiveness of biotechnological production

The development of large-scale biotechnological production with the use continuous cell-line cultures as producers revealed the role of apoptosis in the culture as a factor producing essential influence on the effectiveness of the process, the level of the accumulation of the target product and its quality. The limiting influence of apoptosis as the programmed death of cells in the culture was determined by a number of factors: the chemical composition, pH and chemical properties of the medium; the levels of glucose, amino-acid and vitamin depletion; the uniformity of oxygenation; temperature conditions; the mode of agitation and the intensity of hydrodynamic forces; the content of mitogenetic factors and toxins in the medium; the presence and activity of the expression of apoptosis stimulators and inhibitors. The presence of correlation between the intensity of apoptosis, cultural properties and the characteristics of the mitotic cycle of the cell line was shown. The latter made it possible to regard the biological properties of the producer culture as one of the leading factors modifying the process of the programmed death of cells.     

四膜虫S1有性生殖的电镜观察Ⅱ.接合区的形态与配子核的交换

四膜虫接合膜上的小孔是两接合体细胞质相连的通道。配子核形成后,按合膜由于增生而出现装有细胞器等的囊状折叠,并可脱离下来而落入另一细胞中,这可能是胞质交流的又一途径。配子核的交换不是从膜上原有小孔通过的,而是在溶酶体等作用下、使膜破裂,由核后方的微管推动进入对侧细胞中。 本文记述了四膜虫S1有性生殖过程中接合区的形态和配子核的交换。     

Effects of D-penicillamine on the ultrastructure of hepatocytes and state of the base substance in the liver of rats with experimental cirrhosis

The authors examined the action of D-penicillamine on the ultrastructure of hepatocytes and the condition of the base substance in the rat's liver, with experimental CCl4-cirrhosis. (D-penicillamine was given to these rats during 4 and 6 months). It was discovered that the using of D-penicillamine on the early stages of experiment (until 4 months) reduced the process of the development of the liver cirrhosis. This fact was confirmed by the reducing of the level of base substance in the liver and reducing of the quantity of collagen in the Disse space, as well as by the absence of fibres in the intercellular spaces near sinusoid. When the D-penicillamine was given longer the increasing of the beta-NAG activity with simultaneous severe reducing of the GAG and destruction of hepatocyte's organelles in the experimental rat to the 6 months of experiment were observed. The authors consider that these data are the evidence of the negative effect of the long using of D-penicillamine in the stage of decompensated cirrhosis of the liver.     

Morphologic changes in cultures of different tissues exposed to the toxins of C1. perfringens types B, C, E and F]

There were revealed morphological peculiarities of the action of C1. perfringens toxins, types B, C, D, E and F on the cultures of fibroblasts of chick embryo, amniotic cells and intestinal tissue. The toxin type B was characterized by a marked vocuolization of the cell cytoplasm; the action of the toxin of type C was expressed in the swelling of the nuclei and the lysis of the chromatine substance, the toxin of type E casued kariorhexis, and the toxin of type F--hyperchromatosis of the nuclei. All the cultures proved to be insensitive to the toxin of type D. Peculiarity of the morphological affection of the cells permitted to differentiate toxin of type B in the cultures of the fibroblasts of chick embryo, whereas the toxins of types C, E and F--in the cultures of the amniotic cells under control of the reaction of neutralization with the homologous antitoxic sera.     

Relation of intrahospital morbidity from staphylococcal infections to some properties of hospital strains]

Analysis of staphylococcus infection morbidity in a large obstetrical hospital for 5 years offered a possibility of establishing an association between the severity of the course of staphylococcus infections in patients, the bacteriophage type of the causative agent and its resistance to antibiotics. The qualitative changes in morbidity in the direction of the prevalence of minor forms and mild course ocurred in parallel with the changes of the leading bacteriophage type from the epidemic 75/77 and 80/81 to the nonepidemic bacteriophage types of the III bacteriophage group and the changes of the antibiograms of the causative agents in the direction of an increase in the number of strains sensitive to antibiotics. Since the severity of the course of staphylococcus infection characterized the pathogenicity of the strain of the causative agent a conclusion could be drawn on the association between the sign of virulence and determinants of the medicinal resistance and definite prophages in the hospital strains of staphylococcus.     

Spatial analysis of motor unit potentials of the rat medial gastrocnemius

The spatial analysis of the potentials of single motor units of the rat medial gastrocnemius muscle evoked by stimulation of the fibres of split ventral roots was carried out with a bipolar electrode moving in the direction perpendicular to the longitudinal axis of the muscle fibres. During this movement of the electrode a variability was observed in the time of the biphasic potential from its maximum to minimum, and in the peak-to-peak amplitude of these potentials. The potentials recorded outside the territory of the motor unit had a lower amplitude in relation to the potentials from the territory of the unit. This made localization of the motor unit on the cross-section of the muscle possible. Differences in the duration of the potential from maximal to minimal amplitude (maximum-minimum amplitude time--M-MAT) of each investigated motor unit from successive recording sites reflected the number of fibres contributing to the action potential and the distance of the recording surface of the electrode from the zone of the motor end-plates of this motor unit. The greatest diameter of the territory of the observed motor units reached 2.5 mm.     

Proliferation of piriform neurons in the rat cerebellar cortex in the pre- and postnatal periods of development]

The method of histoautoradiography with the use of H3-thymidine was applied to the study; there were established the periods of appearance in the cerebellar anlage of albino rats of neuroblasts differentiated into the piriform neurones of the cerebellar cortex; dynamics of the proliferative activity of these cellular elements in the course of the pre- and postnatal periods of development of the experimental animals was investigated. On the basis of the material obtained a conclusion was drawn that the last cell divisions (the result of cell differentiation were Purkinje's cells of the cerebellar cortex) stopped by the 13th--15th day of the embryonic development. No incorporation of the labeled precursor into the DNA of the nuclei of the differentiating piriform neurons occurred later.     

Simulation of the hippocampal theta rhythm

Centre of Theoretical and Computational Neuroscience, University of Plymouth, UK Basing on the hypothesis about the mechanisms of the theta rhythm generation, the article presents mathematical and computational models of theta activity in the hippocampus. The problem of the theta rhythm modeling is nontrivial because the slow theta oscillations (about 5 Hz) should be generated by a neural system composed of frequently firing neural populations. We studied a model of neural pacemakers in the septum. In this model, the pacemaker follows the frequency of the external signal if this frequency does not deviate too far from the natural frequency of the pacemaker, otherwise the pacemaker returns to the frequency of its own oscillations. These results are in agreement with the experimental records of medial septum neurons. Our model of the septal pacemaker of the theta rhythm is based on the hypothesis that the hippocampal theta appears as a result of the influence of the assemblies of neurons in the medial septum which are under control of pacemaker neurons. Though the model of the pacemaker satisfies many experimental facts, the synchronization of activity in different neural assemblies of the model is not as strong as it should be. Another model of the theta generation is based on the anatomical data about the existence of the inhibitory GABAergic loop between the medial septum and the hippocampus. This model shows stable oscillations at the frequency of the theta rhythm in a broad range of parameter values. It also provides explanation to the experimental data about the variation of the frequency and the amplitude of the theta rhythm under different external stimulations of the system. The role of the theta rhythm for information processing in the hippocampus is discussed.     

Evoked potentials in the parietal cortex in response to stimulation of the posterolateral nucleus of the thalamus in kittens of different ages

In kittens of the first month of postnatal life, studies have been made of the evoked potentials in the parietal cortex elicited by stimulation of the posterior lateral thalamic nuclei. It is suggested that within the first days of life the EPs result mainly from the electrical activity of the deep (V-VI) layers of the cortex. This suggestion is confirmed by a significant increase in the velocity of the rising phase and the decrease of the duration of the EPs in the deep layers in newborn animals, as well as partial inversion of the negative wave of the EP at the level of these layers in 1-week kittens. Total depth of the median layers in 1-week kittens is twice less than that in 1 month old ones. To the end of the 2nd week, the input of the activity of the median layers into total activity increases: the focus of partial inversion of the negative wave of the EPs is translocated upward to the border of layers II-III. In 1-month kittens, the general pattern of the EPs in the parietal cortex is the same as in adult cats.     

Study of the structural-energy aspects of complementary-addressed modifications of nucleic acid with reactive 4-]N-methyl-N-(2-chloroethyl)-amino]benzyl-3'- or 5'-phosphamide oligonucleotide derivatives by a molecular mechanics method

Calculations of probabilities of the complementary addressed modification of target NA by 3'- or 5'-reactive derivatives of oligonucleotides carrying a 4-[N-(2-chloroethyl)-N-methyl]aminobenzyl group attached to the 3'- or 5'-terminal phosphates through a phosphoroamide linkage have been made. It is shown that the structural basis of the high efficiency and positional specificity depending on the NA target base sequence is the extent of structural correspondence of the energetically optimal conformation of the active group in the complex to the mutual arrangement of the active group and nucleophilic site needed for the chemical reaction. The 3'-derivative has the highest dependence of efficiency and positional specificity of the alkylation on the target NA base sequence. The maximal positional specificity of the alkylation is found for the modification of the cytidine at the first position from the terminal complementary base pair at the 5'-end of the target NA. For the 5'-derivative, the alkylating ability was determined to depend on the insertion of additional methylene bridges into the standard phosphoroamide linker: two methylene groups provide for the maximal increase of the modification ability of the nucleophilic site of the target NA in the double-stranded part of the complex. The efficiency of alkylation of the target NA in a three component complex with oligonucleotide-effector also complementary to the target NA have been studied. It was found that formation of the three-component complex lead to an additional stabilization of the conformation needed for the reaction of the active group, in comparison with two-component complex, by means of the intercalation of the phenyl group of the reagent in the gap between the oligonucleotide derivative and the oligonucleotide effector.     

Cranial and appendicular ontogeny of Bactrosaurus johnsoni,a hadrosauroid dinosaur from the Late Cretaceous of northern China

Abstract: The juvenile anatomy of various cranial and appendicular elements of the hadrosauroid dinosaur Bactrosaurus johnsoni is described in detail. Growth changes are documented from juvenile to adult stages for each skeletal element available. In the studied skull, ontogenetic trends consist of: development of features on the ventral surface of the frontal; reduction in the slope of the posteromedial process of the premaxilla; a posterior shift of the dorsal process of the maxilla; development of concavities on the medial surface of the prefrontal; increased robustness and development of the ventral flange of the jugal; decreased curvature of the long axis of the quadrate; increased ventral deflection of the dentary; and changes in the length/width proportions and depth of the anterior surface of the predentary. In the appendicular skeleton, the majority of ontogenetic variation from juvenile to adult occurs in the limb bones, including increased robustness of the deltopectoral crest of the humerus; relative shortening of the ulna; increased development of the fourth trochanter and mediolateral widening of the distal end of the femur; increased expansion of the cnemial crest of the tibia; and the increased prominence of articular protuberances and flanges of the metatarsals. A survey of the phylogenetically informative characters present in B. johnsoni indicates that several characters concerning the frontal, maxilla, jugal, quadrate, predentary, dentary, scapula, humerus and ilium are affected by ontogeny. Nevertheless, the majority of phylogenetic characters are not ontogenetically variable, suggesting that a substantial amount of the information provided by juvenile and subadult specimens for phylogenetic inference is reliable in basal hadrosauroids.     

考洲洋饵料生物水平综合评价

在GIS(Geographical Information System)的支持下,利用等级模型对1999年2月(枯水期)和8月(丰水期)考洲洋饵料生物水平进行了综合的分析和评价。枯水期考洲洋整个水域饵料生物的分布较均匀,其密集分布区位于湾西北部、湾口和吉隆河口附近水域,达4级水平,饵料生物较为丰富。丰水期饵料生物水平的变化幅度较大,其密集分布区位于湾中部和望京洲沿岸水域,达4-5级,饵料生物最为丰富,其次为湾口,达4级水平。两个调查航次相比,丰水期的饵料生物水平高于枯水期。主要优势种的变化具有明显的季节交叉和演替现象,浮游植物和浮游动物的主要优势种在不同季节差异较大,而底栖生物的优势种组成在整个调查期间变化不大。调查期间各饵料生物的多样性指数和均匀度均呈现出较大的变化,其最大变化范围分别为0.01-4.49和0.01-0.96,表明湾内饵料生物受外界环境条件影响较大,生物群落组成结构和生物多样性水平不太稳定。调查期间整个水域的生物多样性阈值均呈现出湾西部及西北部水域较高,其余水域较低的分布特点,但不同季节其变化趋势及分布范围略有差异。枯水期多样性阈值的密集分布区出现于湾西侧的部分水域,其等级水平为3级,饵料生物多样性较好,其余水域均为2级或低于2级水平,多样性一般或较差。丰水期的分布趋势与枯水期相似,其密集区出现于湾西部和西北部的整片水域中,分布范围比枯水期大,但等级水平明显低于枯水期,为2级,多样性一般,其余大部分水域均为1级水平,多样性较差。       

Mechanism of hypothalamic influences on bile formation]

Acute experiments were conducted on male rats; it was revealed that electrical stimulation of the nuclei of the anterior hypothalamus led to reduction of choleresis and to a fall of the potassium content in the bile, increase of permeability of the connective tissue stroma of the liver and of cell membranes of hepatocytes. Stimulation of the posterior hypothalamic nuclei induced an increase in choleresis, of the concentration of potassium ions and cholates in the liver, and also of the cholinesterase activity in the serum and homogenates of the liver. Permeability of connective tissue structures of the liver and of the intercellular spaces of hepatocytes proved to fall. The influences of the hypothalamus on bile formation included a change in the functional activity of hepatocytes and of the production of a fluid fraction of the bile.     

New findings concerning the spread of natural foci of infection in the transpolar region of eastern Siberia]

New materials are presented on the presence of the foci of anthropozoonozes in the Extreme North. For the first time there was established the existence in the subarctic tundra of the Taimyr peninsula of the arbovirus foci of the tick-borne encephalitis complex. A virus of the tick-borne encephalitis complex was isolated in 1973 from the gamasida ticks Haemogamasus ambulans Thorel. and Hirstionyssus isabellinus Oudms. and the nests of the Siberian lemming Lemmus lemmus L. This pointed to the existence in the Transpolar region of the foci or arboviruses in the nest-hole biocenoses of the lemmings outside the bird colonies. Cultures of tularemia bacilli (which proved the etiology of the epizootic among the lemmings observed in 1973 and also the presence of the lemming natural foci of tularemia and their combination with the arbovirus foci) were isolated from the lemmings at the same territory. The results of serological examination of the local population and of the animals pointed to the circulation in the Transpolar region of the causative agents of leptospirosis, toxoplasmosis, Q-fever and of the Asian tick-borne rickettsiosis.     

The dynamics of intracortical interaction during thinking activities

A new method is described of the brain mapping, based on determination of the probability of appearance of isofrequency components in the EEG derivations allowing to evaluate functional interaction of the brain structures in the process of psychic activity. The process of mental construction of visual image from separate elements includes three stages. At the stage of image search the focus of activity is in the occipital cortical area; in the stage of construction it moves to the frontal cortical areas; completion of the task and verbalization of the image are accompanied by joining of the cortical connections in common system. Alongside with the main focus of activity secondary focuses in the temporal cortex are also revealed during the search of the visual image. The topography of interaction at the frequencies of alpha-range in mainly determined by the stage of image construction. In case of prevalence of the image and abstract thinking shift is marked of the activity focuses at the frequencies of theta-range respectively to the right and left hemispheres.     

Early steps of the conformational change of influenza virus hemagglutinin to a fusion active state: Stability and energetics of the hemagglutinin

A conformational change of the homotrimeric glycoprotein hemagglutinin (HA) of influenza virus mediates fusion between the viral envelope and the endosome membrane. The conformational change of the HA ectodomain is triggered by the acidic pH of the endosome lumen. An essential step of the conformational change is the formation of an extended coiled-coil motif exposing the hydrophobic fusion peptide toward the target membrane. The structures of the neutral-pH, non-fusion active conformation of the HA ectodomain and of a fragment of the ectodomain containing the coiled-coil motif are known. However, it is not known by which mechanism protonation triggers the conformational change of the stable neutral-pH conformation of the ectodomain. Here, recent studies on the stability of the HA ectodomain at neutral pH, the energetics of the conformational change toward the fusion-active state and of the unfolding of the HA ectodomain are summarised. A model for the early steps of the conformational change of the HA ectodomain is presented. The model implicates that protonation leads to a partial dissociation of the distal domains of the HA monomers that is driven by electrostatic repulsion. The opening of the ectodomain enables water to enter the ectodomain. The interaction of water with respective sequences originally shielded from contact with water drives the formation of the coiled-coil structure.     

小麦受精过程中酸性磷酸酶的超微细胞化学定位

小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ ）受精前成熟胚囊,除胚囊中央细胞的合点端细胞质中有酸性磷酸酶外,其余部位均未发现酸性磷酸酶。受精时期,以下部位存在酸性磷酸酶活性：卵细胞的细胞核内一部分染色质和细胞质中大部分线粒体;精、卵核融合时两核的核周腔内;退化助细胞合点端细胞质和一些液泡内;进入雌性细胞中的两个精核;胚囊各成员细胞的细胞壁及胚囊周围珠心细胞的细胞壁。二细胞原胚中未见有酸性磷酸酶。早期胚乳游离核染色质上有酸性磷酸酶。小麦受精过程酸性磷酸酶的分布特点可能与卵细胞生理状态的变化和细胞质中线粒体的改组、助细胞的退化、精核的生理状态以及精核与卵核的核膜融合等有关。     

A clinical and neuropsychological analysis of mental functions in 6- to 7-year-old children

The neuropsychological analysis of the state of higher mental functions (HMF) in children aged 6-7-years entering the first class of the school providing general education showed that the HMF of 52-73% of the future schoolchildren are underdeveloped with respect to their age. The underdevelopment of the emotional-volitional sphere, of the dynamic organization of object activity, audio-speech memory, sphere of images-representations, visually-image and verbally-logical forms of thinking has been revealed. The experimental data suggest the absence of the primary (structural) derangements of the studied HMF in the examined children and dependence of the extent of their formation on the extent of readiness of the voluntary organization of activity. Insufficient formation of the HMF with respect to age is manifested in the lag of the formation of the internal structure of the psychic process, i.e., the absence of interiorization of the psychic processes and formation of the internal mental act. The neuropsychological assessment of underdevelopment of the HMF in reference to age suggests an insufficient age-related maturity of subcortical structures and subcortical corticopetal pathways as well as a dysfunction of the frontal neocortex and a secondary dysfunction of the posterofrontal and TPO areas, non-auditory cortical temporal regions of the left hemisphere due to underdevelopment of connections of these areas with the frontal structures.     

Participation of the beta-adrenergic receptor in the enteroruminal reflex and enteroenteric reflex

In sheep with chronic fistulae of the small intestine and rumen the participation of the beta-adrenergic receptor was investigated in the enteroruminal reflex and enteroenteric reflex using the method of pharmacological analysis. The movements of the segments of the digestive tract with fistulae were recorded by the balloon method. A solution of hydrochloric acid administered into the ileum caused a reflex stimulation of its motor activity and inhibited the movements of the rumen. Intravenous administration of propranolol before instillation of the acid into the intestine abolished or reduced greatly the reflex inhibition of the movements of the rumen and in the small intestine it enhanced significantly the studied reflex reaction. Thus stimulation of the beta-adrenergic receptor plays an important role in the reflex stimulation of the motor activity of the rumen, and stimulation of the motor activity of the small intestine in the enteroenteric reflex is limited by the effects derived from this receptor.