Prospects for the Practical Application of Substrate-Binding Modules of Glycosyl Hydrolases

The properties of substrate-binding modules of glycosyl hydrolases have been reviewed. The variation of the properties of these modules makes them promising as components of chimeric proteins, which is a rapidly developing field of biotechnology. Examples of applying substrate-binding modules of glycosyl hydrolases to the immobilization of proteins and whole cells on polysaccharides and the purification of proteins are described. Promising methods for (1) detecting various compounds using hybrids of substrate-binding modules with antibodies and (2) locating polysaccharides in live tissues are reviewed as well.     

Prospects for practical application of substrate-binding modules of glycosyl hydrolases (A review)

The properties of substrate-binding modules of glycosyl hydrolases have been reviewed. Variation of the properties of these modules makes them promising as components of chimeric proteins, which is a rapidly developing field of biotechnology. Examples of applying substrate-binding modules of glycosyl hydrolases to immobilization of proteins and whole cells on polysaccharides and purification of proteins are described. Promising methods for (1) detecting various compounds using hybrids of substrate-binding modules with antibodies and (2) locating polysaccharides in live tissues are reviewed as well.     

Electrical properties of vertebrate oocyte membranes

The electrical properties of vertebrate oocyte and egg cell membranes are reviewed. Ion channels of these oocytes generate transcellular currents and action potentials as well as responses to neurotransmitters. Electrical properties change during meiotic maturation and fertilization. Available information about the electrical properties of sperm is also discussed.     

Receptor-enzyme interactions. Kinetic characteristics

The kinetic regularities characterizing the behaviour of enzyme-receptor systems underlying molecular mechanisms of transmission and transformation of current information at the cellular level are reviewed. The properties of receptors as molecular detectors responsible for chemical signal "recognition" are described, and the efficiency of enzyme-substrate and effector-receptor interactions is compared. The heterogeneity of receptor populations and kinetic approaches to their discrimination are considered. The principal mechanisms and problems of chemical signal amplification in coupled enzymatic reactions are discussed. The major properties of the ligand-receptor system and its relation to gene expression in receptors as well as mechanisms of cell response "quenching" are reviewed. Some kinetic regularities of desensitization of enzyme-receptor systems are discussed in terms of present-day concepts on desensitization as inactivation of enzyme-receptor systems in the reaction course.     

Phycobiliproteins of blue-green, red and cryptophytic algae]

The present-day concepts on phycobiliproteins, the protein pigments of blue-green, red and cryptophyte algae are reviewed. The functions, distribution, localization, physico-chemical, spectral and immunochemical properties of phycobiliproteins are described. The properties of the polypeptide protein subunits and the composition and chemical structure of chromophores as well as their binding to the apoprotein molecules are discussed.     

Fermentation waste--a biomodifier of concrete

The composition and properties of molasses-containing yeast fermentation waste used as a plasticizer and structural biological additive to concrete mixtures are reviewed. The basic principles of the effects of organic and inorganic components of yeast fermentation waste on the properties of the bonding system are analyzed.     

Use of yeast fermentation waste as a biomodifier of concrete (Review)

The composition and properties of molasses-containing yeast fermentation waste used as a plasticizer and structural biological additive to concrete mixtures are reviewed. The basic principles of the effects of organic and inorganic components of yeast fermentation waste on the properties of the bonding system are analyzed.     

Structure-properties relations in graphene derivatives and metamaterials obtained by atomic-scale modeling

ABSTRACT

Recent findings of atomic-scale modelling studies are reviewed on graphene derivatives and metamaterials fabricated through chemical functionalization and/or defect engineering of graphene sheets. Results of molecular-statics and molecular-dynamics simulations according to a reliable bond-order potential, as well as first-principles density functional theory calculations are reviewed that have established useful structure-properties relations in two-dimensional materials, such as graphene nanomeshes (GNMs), electron-irradiated graphene, and interlayer-bonded twisted bilayer graphene. Quantitative relationships are established for the elastic moduli, mechanical properties, and thermal conductivity of GNMs as a function of the nanomesh porosity and the mechanical response of GNMs to uniaxial tensile straining is explored over the range of nanomesh porosities. The dependence of structural, mechanical, and thermal transport properties of electron-irradiated graphene sheets on the density of irradiation-induced defects is reviewed, highlighting an amorphization transition accompanied by a brittle-to-ductile transition and a transition in thermal transport mechanism beyond a critical defect concentration. The tunability of the electronic band structure, mechanical properties, and structural response to mechanical loading of graphene-diamond nanocomposite superstructures consisting of nanodiamond superlattices in interlayer-bonded twisted bilayer graphene also is demonstrated by precise control of the density and distribution of covalent interlayer C–C bonds.     

利用转基因植物合成生物可降解材料聚羟基脂肪酸酯

聚羟基脂肪酸酯 (polyhydroxyalkanoates,PHAs)因其完全的生物可降解性、良好的物理加工特性以及生物相容性使其应用前途十分广泛。本文综述了利用转基因植物合成PHAs的研究概况和存在问题 ,进一步探讨了其解决方法。     

Tritium diagnostics in a fusion reactor

Methods for controlling tritium in a fusion reactor are reviewed. The characteristic features of the interaction of tritium with surfaces are considered, as well as its diffusive properties and its levels and saturation depths for a number of radioactive materials. New properties of boundary layers and new diffusive properties in the polycrystalline structure of metals are revealed. Unique measurements of the diffusive properties of tritium in stainless steel at room temperature are carried out. It is found that the main contribution to the diffusion process comes from the intergranular tritium flux. The capture of tritium by metals in the ITER device is calculated.     

Bi- or multifunctional opioid peptide drugs

Strategies for the design of bi- or multifunctional drugs are reviewed. A distinction is made between bifunctional drugs interacting in a monovalent fashion with two targets and ligands containing two distinct pharmacophores binding in a bivalent mode to the two binding sites in a receptor heterodimer. Arguments are presented to indicate that some of the so-called “bivalent” ligands reported in the literature are unlikely to simultaneously interact with two binding sites. Aspects related to the development of bi- or multifunctional drugs are illustrated with examples from the field of opioid analgesics. The drug-like properties of the tetrapeptide Dmt¹[DALDA] with triple action as a µ opioid agonist, norepinephrine uptake inhibitor and releaser of endogenous opioid peptides to produce potent spinal analgesia are reviewed. Rationales for the development of opioid peptides with mixed agonist/antagonist profiles as analgesics with reduced side effects are presented. Progress in the development of mixed µ opioid agonist/δ opioid antagonists with low propensity to produce tolerance and physical dependence is reviewed. Efforts to develop bifunctional peptides containing a µ opioid agonist and a cholecystokinin antagonist or an NK1 receptor antagonist as analgesics expected to produce less tolerance and dependence are also reviewed. A strategy to improve the drug-like properties of bifunctional opioid peptide analgesics is presented.     

The methods of surface EMG analysis

The use of surface emg as a tool for quantification is described. First, the specific advantages of the surface emg are discussed. Techniques for analysis of the emg signal which estimate and detect the action potentials of the individual motor units and estimate some global properties of muscle activity are reviewed. A survey of data on relations between the properties of motor unit action potential, the properties of motor unit activity and the results of signal processing are given.     

A primer on peroxiredoxin biochemistry

Peroxiredoxins were not recognized as a family of enzymes until the 1990s but are now known to be the dominant peroxidases in most organisms. Here, the history and fundamental properties of peroxiredoxins are briefly reviewed, with a special focus on describing how an exquisitely tunable balance between fully folded and locally unfolded conformations plays a large role in peroxiredoxin catalytic properties.     

Simple compounds with high pharmacologic potential: beta-carbolines. Origins, syntheses, biological properties

We reviewed the origins, the synthetic pathways and the biological properties of beta-carbolines, the condensation products of tryptophan and indole alkylamines with aldehydes. They were found in many plants, some of which have been used as hallucinogens. They also occur as minor constituents in tobacco smoke. In mammalian body, beta-carboline derivatives occur normally in plasma, platelets and urine, moreover it seems that some are formed in human body after alcohol intake. Due to interesting biological effects described in recent years (inhibition of monoamine oxidase, binding to benzodiazepine receptors, comutagenic and carcinogenic properties, 5-hydroxy tryptamine uptake inhibition), many attempts were made to prepare beta-carbolines starting from various indole derivatives. We reviewed the published methods up to 1975 and summarized the main patents related with pharmacological properties of synthetic beta-carbolines.     

Polyhydroxybutyrate: An intriguing biopolymer

The microbial polymer poly-3-hydroxybutyrate (PHB) and related poly-hydroxyalkanoates, such as poly-3-hydroxyvalerate and poly-3-hydroxyoctanoate, are unique biodegradable thermoplastics of considerable commercial importance. The structure, properties and regulation of synthesis and degradation of PHB are reviewed and the microbial production of copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate, with properties varying according to copolymer composition, is discussed.     

Prosequence-mediated disulfide coupled folding of the peptide hormones guanylin and uroguanylin

In contrast to their prohormones the mature peptide hormones guanylin and uroguanylin are not able to fold to their native disulfide connectivities upon oxidative folding. Structural properties of both peptide hormones and their precursor proteins as well as the role of their prosequences in proper disulfide coupled folding are reviewed. In addition, the structural behavior of a proguanylin mutant that closely resembles prouroguanylin has been investigated to gain further insight into structural properties of this homologous precursor protein.     

放牧对草原土壤的影响

介绍了放牧对草原土壤物理性质 (容重、渗透率 )、化学性质 (有机质、N素 )和微生物的影响。由于草原土壤系统本身的复杂性、滞后性和弹性 ,放牧对土壤性质的影响不尽相同。一般而言 ,随放牧强度的增大 ,动物践踏作用的增强 ,土壤孔隙分布的空间格局发生变化 ,土壤的总孔隙减少 ,特别是大孔隙 (>5 0μm)和较大中等孔隙 (9～ 5 0μm)减少 ,使土壤容重增加 ,土壤的渗透阻力加大 ,土壤的保水和持水能力下降。但在有机质含量很低的沙质土壤中 ,超载过牧 ,造成有机质含量降低 ,土壤的团粒结构减少 ,稳定性团聚体减少 ,土壤结构遭到破坏 ,使得土壤容重反而降低。土壤有机质和放牧之间存在复杂的相互关系 ,土壤有机质对放牧的响应受多种因素的影响 ,这些因素包括植被和土壤的初始状况 ;环境因素 ,特别是水分和温度 ;放牧历史 (强度、频率、持续时间和动物类型 )。同时 ,土壤有机质含量低的土壤比含量高的土壤更易受放牧的影响 ,而使有机质发生变化。土壤微生物量碳是最具活性的土壤碳库 ,对环境的变化敏感 ,能较早地指示生态系统功能的变化。当考虑时间尺度时 ,高强度放牧对土壤肥力有负面的影响 ,短期内 ,由于加速了养分的循环效率 ,产生有利的影响 ,但长期无管理的超载放牧必然造成系统物质 (资源 )输入和输     

Properties of enzymes that recognize modified structures in DNA

The properties of the major classes of DNA repair enzymes, such as DNA glycosylases, AP-endonucleases, incision nucleases, and alkyl transferases, are reviewed. With the exceptions of the incision nucleases, the properties of the enzymes are quite similar in prokaryotic and eukaryotic cells. The incision nucleases probably do not recognize the modified base residues as such, but rather helical distortion brought about by the modifying agents. The other classes of enzymes are more or less specific for certain modified structures.     

Structure–Function Relationships of the Vasopressin Prohormone Domains

1. In this review the structure–function relationships of the different vasopressin prohormone domains are dated and discussed, with special reference to the neurophysin and glycopeptide domains.2. The primary structures of the currently known neurophysins and glycopeptide sequences are compared and discussed.3. The hormone-binding and aggregational properties of neurophysin are reviewed and related to a possible function within the regulated secretory pathway.4. It is proposed, based on the properties reviewed here as well as our own data shown here, that the sorting of the vasopressin prohormone is initiated by hormone binding, which triggers aggregation of the prohormone into the characteristic dense cores of the regulated secretory pathway.5. This may suggest that prohormone sorting into the regulated secretory pathway is, in general, determined by noncovalent, intramolecular interactions that promote aggregation.     

Acatalasemia

Summary The abnormalities in acatalasemia at the gene level as well as properties of the residual catalase in Japanese acatalasemia are historically reviewed. The replacement of the fifth nucleic acid, guanine, in the fourth intron by adenine in the acatalasemic gene causes a splicing mutation and hence a deficiency of mRNA. The guanine-to-adenine substitution was detected in two Japanese acatalasemic cases from different families. The properties of the residual catalase are similar to those of normal catalase; the exons are identical. The properties of the residual catalase and the molecular defect in the catalase gene are compared among Japanese, Swiss, and mouse acatalasemias. The physiological role of catalase, as judged from human acatalasemic blood and acatalasemic mice, is also described.