Stevioside

Stevioside is a natural sweetener extracted from leaves of Stevia rebaudiana (Bertoni) Bertoni. The literature about Stevia, the occurrence of its sweeteners, their biosynthetic pathway and toxicological aspects are discussed. Injection experiments or perfusion experiments of organs are considered as not relevant for the use of Stevia or stevioside as food, and therefore these studies are not included in this review. The metabolism of stevioside is discussed in relation with the possible formation of steviol. Different mutagenicity studies as well as studies on carcinogenicity are discussed. Acute and subacute toxicity studies revealed a very low toxicity of Stevia and stevioside. Fertility and teratogenicity studies are discussed as well as the effects on the bio-availability of other nutrients in the diet. The conclusion is that Stevia and stevioside are safe when used as a sweetener. It is suited for both diabetics, and PKU patients, as well as for obese persons intending to lose weight by avoiding sugar supplements in the diet. No allergic reactions to it seem to exist.     

ADP-ribose and cADP-ribose--endogenous regulators of cellular ionic balance. Cardiotropic effects of ADP-ribose

Functions and possible mechanisms of action of adenosine diphosphate ribose (ADP-ribose) and its cyclic analogue--cycle-ADP-ribose (cADP-ribose)-- substances pretend to role of novel second messengers are reviewed. Possible mechanisms of ADP-ribose and cADP-ribose synthesis regulation and metabolism are analyzed. Prospective mechanisms of ADP-ribose and cADP-ribose transportation into the cell are described. ADP-ribose and cADP-ribose are considered as endogenous regulators of ionic balance (in particular regulators of calcium balance) in different tissues. Effects of ADP-ribose on isolated heart of frog and warm-blooded animal (rat), as well as on rat heart in vivo are discussed. The role of ionic channels and receptors, gated by ADP- and cADP-ribose in regulation of cardiomyocyte ionic balance in normal and pathological condition are analyzed. The possible role of purine receptors in ADP-ribose and cADP-ribose effects on heart are discussed.     

盐生植物种子的休眠、休眠解除及萌发的特点

本文讨论了盐生植物种子的休眠、休眠解除及萌发的特点,主要内容有：(1) 盐生植物种子的休眠类型;(2) 打破盐生植物种子休眠的必要条件;(3) 盐生种子萌发与土壤盐度的关系。并讨论了盐度抑制盐生植物种子的机理。最后,作者提出了将来研究盐生植物种子萌发需要解决的几个重点问题以及研究盐生植物种子休眠和萌发问题的意义。     

QS-type bacterial signal molecules of nonpeptide origin

This review classifies and analyzes the literature data on bacterial autoinducers (AI), the signal molecules produced and secreted by bacterial cells and responsible for intercellular communication (quorum sensing, QS). The most important families of nonpeptide AI are discussed, including N-acyl homoserine lactones, derivatives of 2-methyl-2,3,4,5-tetrahydroxy tetrahydrofuran, indole and quinoline derivatives, and adrenalinerelated compounds. The data is provided on the intracellular and membrane receptors specifically binding to AI, as well as on the effector systems that are activated by AI and mediate their regulatory effects. The possible role of some vertebrate hormones (adrenergic agonists, serotonin, etc.) as AI and their effect on bacterial activity are discussed. The data are presented suggesting a high efficiency of AI-based antibacterial preparations, which selectively disrupt the bacterial information network and thus suppress bacterial infections.     

盐生植物种子的休眠、休眠解除及萌发的特点

本文讨论了盐生植物种子的休眠、休眠解除及萌发的特点 ,主要内容有 :( 1 )盐生植物种子的休眠类型 ;( 2 )打破盐生植物种子休眠的必要条件 ;( 3)盐生种子萌发与土壤盐度的关系。并讨论了盐度抑制盐生植物种子的机理。最后 ,作者提出了将来研究盐生植物种子萌发需要解决的几个重点问题以及研究盐生植物种子休眠和萌发问题的意义     

The proteinase inhibitors of plants and micro-organisms

Recent (post-1972) advances in our knowledge of the proteinase inhibitors of plants and micro-organisms are reviewed. Details of the specificity, occurrence and distribution of these proteins are summarized, and modern methods for their isolation, purification and assay are discussed. Certain homologies revealed by comparison of the amino acid sequences of several inhibitors are noted. Details of their reactive (inhibitory) sites are tabulated and discussed in relation to the proposed mechanisms of action of these proteins. Recent experiments on the intracellular localization of the inhibitors, their physiology and possible functional roles are described. The nutritional significance, possible therapeutic use and value of the proteinase inhibitors as laboratory tools are also discussed.     

综述:羰基应激与衰老机理及阿尔茨海默病早期分子病因

本文从人体衰老过程中重要的共性生化过程——羰基应激——的角度出发,探讨老年性痴呆,主要指阿尔茨海默病(AD),发生发展的早期分子病因．首先,讨论与脂类、碳水化合物和蛋白质自由基氧化(氧应激)和非酶糖基化(糖应激)产生的羰基毒化作用相关的化学反应．接着,列举活性羰基在AD患者体内存在的证据并探究这些羰基毒素对细胞结构与功能的影响．最后,分析和归纳脑组织中针对羰基毒化的解毒机理,进而探讨寻找基于该机理防治AD以至抵御衰老、疲劳、亚健康的方法与途径．     

Davydov Soliton Dynamics in Proteins: III. Applications and Calculation of Vibrational Spectra

The mechanism for energy and signal transport in proteins as suggested by Davydov is discussed. The idea is based on a coupling of amide-I oscillators to acoustic phonons in a hydrogen bonded chain. Results as obtained with the usually used ansätze are discussed. The quality of these states for an approximate solution of the time-dependent Schrödinger equation is investigated. It is found that the semiclassical ansatz is a poor approximation, while the more sophisticated |D₁> state seems to represent the exact dynamics quite well. This was shown by extensive calculations, both analytically and numerically in the two preceding papers. Calculations at a temperature of 300K for one chain, as well as for three coupled ones (as they are present in an α-helix) are presented and discussed. From the calculations it is evident, that Davydov solitons are stable for reasonable parameter values at 300K for special initial excitations close to the terminal sites of the chain. Further vibrational spectra are presented and discussed. Our results suggest, that due to their strong dependence on the initial state, the Davydov |D₁> model system might be a (quantum) chaotic one.     

Further studies of drought resistance in woody plants

This publication is an extension of the 1956 review of drought resistance in woody plants. The more important recently used terms are listed and defined. Summaries of reports of drought effects on forest trees are presented in tabular form. Frost-drought is discussed as an important factor in the limitation of woody plants’ geographical ranges. The role that droughts play in the initiation of tree diseases is considered, especially in the light of new evidence from studies of diebacks-declines of forest trees. Interactions between soil moisture and transpiration are discussed as well as ways to control transpiration in large stands. Also considered are drought experiments with tree seedlings and symptomatology of drought injury. The means by which woody plants survive drought (excluding ephemerals) are discussed.     

Influence of amphiphilic compounds on membranes

On the basis of Gortel & Grendel (J. Exp. Med., 1925, 41, 439-494) discovery, the importance of the lipid bilayer as an integral and indispensible component of the cell membrane is discussed. In particular, attention focuses on the interaction between membranes and amphiphilic substances. The effect on membranes of quaternary ammonium salts, both in the form of pesticides and oxidants as well as organic compounds of tin and lead are discussed in greater detail.     

Cloning, restriction digestion and DNA labeling of large DNA fragments (greater than or equal to 1 kb) in the presence of remelted SeaPlaque GTG agarose gels.

Large DNA fragments (greater than or equal to 1 kb), separated in low melting temperature SeaPlaque GTG agarose gels, can be enzymatically processed directly in the presence of this agarose (in-gel). Time saving protocols are discussed for in-gel processing of large DNA fragments in the presence of remelted SeaPlaque GTG agarose, including cloning into pUC18, nick translation, random priming and restriction digestion. These in-gel molecular biology techniques are as efficient as those using DNA recovered from agarose. The effects of UV irradiation, Mg2+ concentration and agarose concentration on selected in-gel protocols are also discussed.     

Oxidized phospholipids: from molecular properties to disease

Oxidized lipids are generated from (poly)unsaturated diacyl- and alk(en)ylacyl glycerophospholipids under conditions of oxidative stress. The great variety of reaction products is defined by the degree of modification, hydrophobicity, chemical reactivity, physical properties and biological activity. The biological activities of these compounds may depend on both, the recognition of the particular molecular structures by specific receptors and on the unspecific physical and chemical effects on their target systems (membranes, proteins). In this review, we aim at highlighting the molecular features that are essential for the understanding of the biological actions of pure oxidized phospholipids. Firstly, their chemical structures are described as a basis for an understanding of their physical and (bio)chemical properties in membrane- and protein-bound form. Secondly, the biological activities of oxidized phospholipids are discussed in terms of their unspecific effects on the membrane level as well as their potential interactions with specific targets (receptors) affecting a large set of (signaling) molecules. Finally, the role of oxidized phospholipids as important mediators in pathophysiology is discussed with emphasis on atherosclerosis.     

Quantitative measures of cortical functional connectivity: A state-of-the-art brief survey

The modern concepts of quantitative measurement of the strength of functional and effective cortical connectivity in neurocognitive networks (large-scale distributed brain systems of interacting neuronal populations that are believed to underlie cognitive processing) are reviewed. The two main classes of the methods of connectivity assessment (linear and nonlinear) are discussed. In the class of linear methods, in addition to coherence routinely used to measure the strength of functional links, the vector autoregressive modeling of multichannel EEG is discussed in detail. The latter technique allows the estimation of both functional and effective connectivity, i.e., the measures such as directed transfer function (DTF) and direct partial coherence (PDC) extensively used in cognitive neuroscience. The impact of volume conduction on different estimates of connectivity is considered and the imaginary part of complex-valued coherence as a way to reduce the artificial influence of volume conduction is discussed. Independent component analysis (ICA) and transfer entropy as a method of estimating direct influence are reviewed in the class of nonlinear methods.     

On Dysosma Woodson and Sinopodophyllum Ying,gen. nov. of the Berberidaceae

1. A classification is made on seven species of the genus Dysosma, of which four are proposed as new combinations, and one as new species. 2. The pollens of six species in the genus Dysosma and two species of Podophyllum are examined. Morphologically, the Asiatic. P. emodi is radically distinct from the North American P. peltatum and can be separated from Podophyllum as an independent genus-Sinopodophyllum. 3. The trend of evolution in Dysosma (fig. 2)and its relationships with the genera Sinopodophyllum and podophyllum are discussed. 4. Based on the evidence from an analysis of the ecology and geographical distribution of the component species (fig. 3), the problem of the centre of development of the genus Dysosma has been discussed.     

Pollution biomarkers in estuarine animals: critical review and new perspectives

In this review, recent developments in monitoring toxicological responses in estuarine animals are analyzed, considering the biomarker responses to different classes of pollutants. The estuarine environment imposes stressful conditions to the organisms that inhabit it, and this situation can alter their sensitivity to many pollutants. The specificity of some biomarkers like metallothionein tissue concentration is discussed in virtue of its dependence on salinity, which is highly variable in estuaries. Examples of cholinesterase activity measurements are also provided and criteria to select sensitive enzymes to detect pesticides and toxins are discussed. Regarding non-specific biomarkers, toxic responses in terms of antioxidant defenses and/or oxidative damage are also considered in this review, focusing on invertebrate species. In addition, the presence of an antioxidant gradient along the body of the estuarine polychaete Laeonereis acuta (Nereididae) and its relationship to different strategies, which deal with the generation of oxidative stress, is reviewed. Also, unusual antioxidant defenses against environmental pro-oxidants are discussed, including the mucus secreted by L. acuta. Disruption of osmoregulation by pollutants is of paramount importance in several estuarine species. In some cases such as in the estuarine crab Chasmagnathus granulatus, there is a trade off between bioavailability of toxicants (e.g. metals) and their interaction with key enzymes such as Na(+)-K(+)-ATPase and carbonic anhydrase. Thus, the metal effect on osmoregulation is also discussed in the present review. Finally, field case studies with fish species like the croaker Micropogonias furnieri (Scianidae) are used to illustrate the application of DNA damage and immunosuppressive responses as potential biomarkers of complex mixture of pollutants.     

Further Results in Indices for Diagnostic Screening II

This article is in continuation of a previous one on properties of diagnostic indices (Bennett, 1976). Results are presented on biases in sample estimates of the sensitivity (ξ) and specificity (η) of a diagnostic test T for a disease, as well as their asymptotic variances. The problem of combining estimates of ξ, η from various clinical centres and obtaining appropriate confidence limits is also discussed. A numerical example is also given. (Tables 1a, b). The log-linear model for ξ, η is also discussed.     

Stereospecific opioid drug receptors on excitable cell membranes

In the past decade evidence has accumulated showing that there are stereospecific opioid drug receptors located on the surface membranes of neurones and skeletal muscle fibres which can block action potentials when opioid drugs are applied to the cells. The nature of this evidence and the difficulties involved in this area of investigation are discussed in detail. Two different mechanisms have been described for this depression of excitability; one, a direct blocking action on sodium channels (or the calcium channels in the case of cells with calcium action potentials) and the other, a stimulation of membrane potassium conductance which results in hyperpolarization and increased membrane conductance both of which decrease excitability. For the most part these different mechanisms seem to prevail in different cell types as will be discussed. Some other points discussed are as follows: first, in higher doses (or concentrations) opioids produce a local anestheticlike effect which cannot be antagonized by opioid antagonists; next, the opioid antagonists which are easily easily available and commonly employed change from antagonists to agonists as their concentration is increased; and finally, the evidence required for the demonstration of stereospecific opioid receptors is considered in some detail.     

Very Long-Chain Fatty Acids in Composition of Plant Membrane Lipids

Literary data on very long-chain fatty acids (VLCFAs) that are present in polar lipids of the plant cell membranes are discussed. Large amounts of VLCFA are found in polar lipids of some cellular organelles as well as in nonextractable lipids from diverse plant objects, where the influence of surface lipids on the relative content of these FAs is excluded. In some plants, the VLCFA fraction in membrane lipids increases under several kinds of stress. Amounts and diversity of VLCFAs are lower in flowering plants as compared with the representatives of more ancient taxons—gymnosperms, ferns, and marine algae. Presence of VLCFAs in the composition of annular lipids of the cell membranes is assumed. Biosynthesis of VLCFAs, enzymes involved in the process, and encoding genes are discussed.     

Specific steroid-binding glycoproteins of human blood plasma: novel data on their structure and function

In this review, the modern data on the polypeptide and carbohydrate structures of human corticosteroid-binding globulin (CBG) and sex hormone-binding globulin (SHBG) as well as on the biochemical properties and biological functions of these steroid-binding glycoproteins are discussed.