Principles of formalizing a quantitative evaluation of the genetic danger of chemical compounds for man

Specific characteristics of the mutagenic effect of chemicals, which must be taken into account in developing the test system to assess the potential genetic risk caused by chemical substances, are considered. The organizational principles of the procedures currently available for testing and ranking chemicals by their mutagenic and carcinogenic hazard to humans are discussed. The use of selective information suggested by Wiener and Shannon as an efficiency measure of testing and estimating the potential genetic hazard of chemical substances is substantiated. The feasibility of this approach was demonstrated by testing the efficiency of the battery of two short-term in vitro tests as an example. It was shown that selective information is able to serve as an integral universal criterion of the efficiency of testing, if either one test or the test battery were used.     

超级高产小麦旗叶荧光动力学研究

探明超级小麦品种的旗叶光合作用与荧光动力学特性,为超级小麦品种选育利用提供理论依据。以超级小麦临麦4号为试验材料,应用CI-301PS型便携式光合作用测定系统和FMS-2便携式荧光测定仪(英国Hansatech公司)在田间试验中测定旗叶光合作用与荧光动力学参数。结果表明,与普通高产对照品种皖麦52和烟农19相比,超级小麦临麦4号的光合作用参数光合速率、光饱和点和CO2饱和点、羧化效率高,光补偿点和CO2补偿点低;光合机构系统工作参数PSII实际的光化学效率(ΦPSII)、光化学猝灭系数(qP)、PSII反应中心的激发能捕获效率(Fv/Fm)、PSⅡ潜在活性Fv/Fo和电子传递速率(ETR)值高,非光化学猝灭系数(NPQ)值低。这表明超级小麦临麦4号的光合机构系统工作能力强和工作效率高,保证旗叶光合作用的高效运行,为子粒灌浆提供充足的能量和碳水化合物。     

Electroflotation packing of mycelial wastes

Data on testing a pilot plant for electroflotative packing of mycelial wastes are presented. Both the mycelial wastes and their mixtures were used. Concentration of dry substances raged from 3.5 to 131 g/l. The process was performed with varying flow density and consumption rate of the liquid supplied to the plant. Insoluble magnetite and ruthenium oxide anodes were used. The moister content in the packed phase was 81-97.5 per cent. The study provided specification of the process technological parameters and investigation of the flotator hydroulic characteristics.     

吸收胞外电子的电活性微生物

可吸收胞外电子的电活性微生物(Electroactive microorganisms,EAMs)可利用胞外固态载体的电子将二氧化碳或其他氧化态物质还原成胞外有机物、还原态无机物或自身生命活动所需的有机物。该类EAMs的出现拓宽了人们对微生物多样性的认识,在生物质能合成、污染物治理与化学物质检测等方面具有重要的应用价值。本文介绍了代表性的可吸收胞外电子EAMs的物质转化与电能转化率等基本特性,重点阐述该类EAMs基于膜蛋白的直接吸收电子机制,及基于电子穿梭体的间接吸收电子机制,提出了其在微生物电合成系统与微生物传感器中的应用前景,并从EAMs机理研究、生物膜微观机制及工程应用的角度展望其今后的研究方向。     

红豆草根瘤侵染细胞中液泡内含物的超微结构特征

用透射电镜研究了红豆草（Onobrychis viciifolia）根瘤侵染细胞中液泡内含物的超微结构特征。结果表明,早期发育侵染细胞的液泡中只含有少量的纤维状物质。随着细胞的发育,液泡不断变大,液泡中的纤维状物质和膜状物质越来越多。在中央液泡形成后,液泡中的纤维状物质逐渐减少,类细胞质、泡状和膜状物质明显增多,它们常由一层来自液泡膜的膜包围,其形状一般近似圆形或椭圆形。液泡内含物的大量出现可能与红豆草及其根瘤具有高度的抗旱件有关。     

The Effects of Cryoprotective Substances on the Mechanical Stability and Geometric Parameters of Human Erythrocytes

The aim of this study was to examine the effects of sucrose, dextran, polyethylene glycol, glycerol, and mannitol, which possess cryoprotective properties to various degrees, on the mechanical stability and the geometric parameters of human erythrocytes. All substances, except mannitol, contributed to a decrease in hemolysis, which was caused by the movement of small beads. Glycerol and polyethylene glycol, which provide the highest level of protection of erythrocytes during cryopreservation, also showed the maximum efficiency under mechanical stress. Changes in cell resistance may be associated with the transformation of their geometric parameters. According to the cytometry data, 5% solutions of all the substances, except mannitol, caused similar changes in the geometric parameters of the cell. The relationship between changes in the mechanical stability and the geometric parameters of erythrocytes under the influence of cryoprotective agents may be caused by the modification of the membrane?cytoskeleton protein complex, which controls the mechanoelastic properties and morphology of erythrocytes.     

Influence of Work Conditions at Polyethylene Film Producing Plants on Certain Psychophysiological Characteristics and the Health of Workers

This study presents the results of a survey of polyethylene film casting machine operators. A complex of professionally important psychophysiological characteristics was analyzed and a risk assessment for basic pathological symptoms was conducted. It was shown that the mental efficiency and health status in polyethylene casters are suppressed in comparison with control subjects having no contact with the chemical substances.     

Bacterial anaerobic respiration and electron transfer relevant to the biotransformation of pollutants

Bacterial anaerobic respiration is one of the most ancient and essential metabolism processes, possessing the characteristics of both flexibility and high diversity, and a very close relationship with the physiological function in the ecological environment. Under anaerobic conditions, bacteria and anthropogenic substances can form coupling process facilitating terminal electron transfer. Several forms of bacterial anaerobic respiration and electron transfer related to the biotransformation of pollutants, including respiration with humics, sulfonates, halogenated chemicals, azo compounds, TNTs, metallic and non-metallic elements, are reviewed in this paper. These respirations and electron transfers on diverse electron acceptors in the environment have important biotechnological implications because these biochemical reactions have their roles on the transformation/degradation of toxic substances and the cycling of organic carbon as well as many inorganic elements. Furthermore, remediation of sites contaminated with toxic pollutants based on bacterial anaerobic respirations is being recognized widely.     

Hygienic examination of the stimulating effect on the organism of a complex of natural substances

No exhaustive hygienic studies have been conducted yet of the natural substances present in the atmosphere. A complex of natural substances was shown to affect EEG parameters, subjective perception of one's health and general perception. The concentration of the vapours of a mixture of substances was kept at 0.1 mg/m3 which is characteristic of mountainous air. The inhalation of the natural substances was shown to alter the EEG indicators and subjective perception of tested subjects, suggesting a stimulatory effect on the central nervous system. The natural substances proved to stimulate the efficiency of mental and manual work, self-perception and mood. These effects can be accounted for by the positive biological influence of the mountainous atmosphere.     

Application of alkaliphilic biofilm-forming bacteria to improve compressive strength of cement-sand mortar

The application of microorganisms in the field of construction material is rapidly increasing worldwide; however, almost all studies that were investigated were bacterial sources with mineral-producing activity and not with organic substances. The difference in the efficiency of using bacteria as an organic agent is that it could improve the durability of cement material. This study aimed to assess the use of biofilm-forming microorganisms as binding agents to increase the compressive strength of cement-sand material. We isolated 13 alkaliphilic biofilmforming bacteria (ABB) from a cement tetrapod block in the West Sea, Korea. Using 16S RNA sequence analysis, the ABB were partially identified as Bacillus algicola KNUC501 and Exiguobacterium marinum KNUC513. KNUC513 was selected for further study following analysis of pH and biofilm formation. Cement-sand mortar cubes containing KNUC513 exhibited greater compressive strength than mineral-forming bacteria (Sporosarcina pasteurii and Arthrobacter crystallopoietes KNUC403). To determine the biofilm effect, Dnase I was used to suppress the biofilm formation of KNUC513. Field emission scanning electron microscopy image revealed the direct involvement of organic-inorganic substance in cement-sand mortar.     

Efficiency of the prediction of carcinogenic activities of chemical substances based on scoring somatic mutations in the soybean Glycine max (L.) Merrill

The efficiency of scoring somatic mutations in soybean (Glycine max (L.) Merrill) leaves as a test for carcinogenic activity of chemical substances in rodents has been evaluated. The efficiency of the test used alone or as part of a battery of tests has been estimated. The mutagenic activities of some chemical substances estimated using the soybean test are presented. Selective information on the carcinogenic activities of substances obtained in special carcinogenicity tests has been used as a quantitative measure of the efficiency of the tests with soybean leaves. To estimate the weight of evidence for the presence of this activity in the tested substances, a special function has been used whose values are uniquely related to the complete information, which is the sum of a priori information and the information obtained after testing. In general, the results have shown that the somatic mutation score test using soybean leaves is at least as efficient as the well-known tests that are generally used now, such as the Ames test and the chromosome aberration score test using mammalian cells in vitro. This test may be promising for the formation of efficient short-term test batteries.     

A reexamination of the chelex competitive calcium binding assay

The chelex competitive calcium binding assay has been examined as a tool for the analysis of the kinetic parameters of calcium binding substances. Scatchard analysis of calcium binding demonstrates that chelex binds calcium with apparent negative cooperativity or with more than one class of calcium binding sites, and therefore, cannot be used to provide accurate estimations of the dissociation constant or total number of binding sites on an unknown ligand. Results presented in this study indicate that the chelex assay can be effectively used for the qualitative detection of calcium binding substances in tissue extracts or biological fluids.     

Use of a Chemical Sanitizer for Cleaning Fish Boxes

A number of organic, inorganic and surfactant substances were tested for their cleaning efficiency, ability to reduce bacterial load and deodorize fish boxes. A 0.1% iodine solution had good bactericidal and deodorizing properties, whilst a number of surfactants, especially the quaternary compound Quat-LTM, had good cleaning and bactericidal properties. None of the substances used possessed all three desirable properties sought for in this study.     

Antioxidative and Prooxidative Abilities of some Biological Substances and Physiologically Active Substances on the Oxidation of Unsaturated Fatty Acids

Some biological substances and physiologically active substances such as amino acids, hormones, vitamins, medicines and the other substances were added into the linoleic acid solution; and antioxidative and prooxidative abilities of these substances, the abilities to act as electron donors or acceptors, were tested. Many substances were effective as the antioxidant and some others showed prooxidative effects. These facts suggested the possibility of the occurrence of many reactions involving the transfer of an electron among biological processes.     

Freeze-fracture autoradiography: feasibility

We have shown that the combination of freeze-fracture with electron microscope autoradiography can be developed into a technique for correlating the molecular structure of the biological membrane with its chemical and functional characteristics. Within the limits of electron microscope autoradiographic resolution, FARG has the potential to detect the relative distribution of molecules in each half of the membrane and within the plane of the membrane. The use of radioisotopic labels in combination with freezing techniques requires minimal perturbation of the system being studied and may be suitable for the examination of substances which would be extracted or would diffuse during the normal fixation and embedding procedures used in standard electron microscope autoradiography.     

生物处理策略改善麸皮酚类化合物的生物可及性*

麸皮为谷物加工副产物,麸皮酚类物质具有重要的营养特性和药理效应,但麸皮酚类物质大多以结合态形式存在,生物可及性较低,如何实现麸皮中酚类物质有效释放,提高生物利用度存在挑战。综述了麸皮酚类化合物营养特性及其存在形式,以及酶促降解法、微生物发酵法等生物处理策略在提高酚类生物可及性的研究进展;并指出,麸皮预处理技术耦合混菌发酵技术是驱动麸皮酚类物质高效释放的有效途径。探究混合菌种体系的互作关系及其作用机制,关联预处理麸皮的结构变化与降解增效之间的关系,为麸皮高附加值利用以及相关功能性食品开发提供理论依据。     

标准品制备方法对FQ-PCR定量基因表达水平的影响

实时荧光定量PCR (FQ-PCR)标准曲线法准确定量基因表达的关键在于标准品与待检样本的扩增效率是否一致. 为检测DNA标准品与样本cDNA扩增效率的一致性,探讨定量用标准品的最佳制备方法,本研究以脂肪酸结合蛋白5(Fabp5)、过氧化物酶体增殖活化受体α (Ppar-α)及β肌动蛋白（β-Actin）的3个基因为对象,分别采用质粒纯化法、PCR产物直接纯化法、PCR产物凝胶回收法制备DNA标准品,10倍梯度稀释后用FQ PCR制作标准曲线. 并以10倍梯度稀释的样本cDNA标准曲线的参数为对照,进行比较分析. 结果表明,不同方法制备的DNA标准品的扩增效率差异较大,并且与cDNA的扩增效率不一致,不能对cDNA样本进行准确定量. 另外,虽然目的基因在cDNA样本中的拷贝未知,不能对基因表达水平进行绝对定量,但因不同cDNA样本的同一基因的扩增效率一致, 可对基因的表达进行准确的相对定量.     

Biomass, Oleate, and Other Possible Substrates for Chloroethene Reductive Dehalogenation

Comparative studies were conducted with benzoate, propionate, oleate, tetrabutyl orthosilicate (TBOS), and biomass as substrates for dehalogenation of cis-1,2-dichloroethene (cDCE). All five substrates supported dehalogenation. Sufficient calcium was required to precipitate oleate and thus reduce its toxicity to the dehalogenating microorganisms. More cDCE was dehalogenated with TBOS than with benzoate, although TBOS initially had an inhibitory effect. The most efficient dehalogenation was associated with biomass, 20% of which was used for dehalogenation, even higher than the 17% obtained with propionate. The advantages and disadvantages of these organic substances for introduction into an aquifer as electron donors for in situ dehalogenation were examined in terms of efficiency of electron use for reductive dehalogenation, and method and ease of introduction into the aquifer. Benzoate and propionate are useful for recirculation systems, while TBOS, oleate, and biomass are appropriate for more passive approaches.     

Patterns in air pollution as model for the physical basis for olfactory navigation in pigeon homing

Spatial distribution and temporal variability of air pollution were used as a model to describe the stability and predictability of the distribution of airborne substances, postulated by some to be used by homing pigeons to navigate. If the man-made substances reflect the distributional characteristics of natural airborne substances, navigation based on airborne substances is unlikely to be possible.