一些小麦白粉病抗源抗性基因鉴定分析

研究鉴定了我国３７份小麦白粉病抗源的抗性基因,１９份材料不具有任何抗性基因;６份材料具有来自１ＢＬ／１ＲＳ易位系的抗性基因Ｐｍ８;５份材料具有抗性基因Ｐｍ５ａ;３份分别具有对目前欧洲所有生理小种均抗的抗性基因Ｐｍ２１、Ｐｍ１６和Ｐｍ１２;４份材料具有新的抗性基因。     

Histologic classification and differential diagnosis of mesothelioma.

Controversy surrounds the diagnosis, classification, and therefore the epidemiology of those tumors which have been designated as mesotheliomas. The group includes lesions which are as broadly different as benign fibrous lesions which some authors refer to as fibromas and anaplastic tumors which are extremely difficult to differentiate from peripheral lung cancers. The former are benign tumors which are usually readily resected and therefore cured. The latter are unresectable tumors which are invariably fatal and which may terminate with extensive metastatic disease. The reasons for including all of these lesions under the category of mesothelioma and the differential diagnosis of the various types is discussed.     

植物抗真菌病害基因工程研究进展

从表达水解酶、植物病程相关蛋白、抗真菌蛋白、病原毒性因子失活蛋白、抗病基因、植保素合成限速酶、植物细胞壁结构修饰分子、植物抗生反应调节基因等角度综述了植物抗真菌病害基因工程的策略,并就各种策略的研究进展,存在问题和发展趋势进行了探讨。     

Recent concepts in the clinical pharmacology of anithypertensive drugs

As yet, no perfect drug has been found which can reduce supine and standing blood pressure equally, alter primarily peripheral vascular resistance, increase flow to the kidneys and be free of untoward effects. The thiazides, which act directly on the vessels and alpha methyl dopa, which causes an incomplete sympathetic blockade, are the two agents which come closest to the ideal. The advances which have resulted from the discovery of the false neurotransmitters may be expected to lead to the discovery of non-toxic drugs which cause subtle changes in the nerve ending and more controlled sympathetic blockade.     

Inhibition of development in Dictyostelium discoideum by sugars.

Sugars such as glucose, maltose, and trehalose, which are metabolized by Dictyostelium discoideum and which enhance vegetative growth, inhibit the development of the slime mold at concentrations which stimulate growth maximally. They block the acquisition of aggregation competence as well as aggregation. The same sugars also inhibit the degradation of preformed glycogen ribonucleic acid, and protein, which is characteristic of development and which occurs when the amoebas are starved by incubation in dilute phosphate buffer.     

Simulated microgravity perturbs actin polymerization to promote nitric oxide-associated migration in human immortalized Eahy926 cells

Apicomplexan parasites obligatorily invade and multiply within eukaryotic cells. Phylogenetically, they are related to a group of algae which, during their evolution, have acquired a secondary endosymbiont. This organelle, which in the parasite is called the apicoplast, is highly reduced compared to the endosymbionts of algae, but still contains many plant-specific biosynthetic pathways. The malaria parasite Plasmodium falciparum infects mammalian erythrocytes which are devoid of intracellular compartments and which largely lack biosynthetic pathways. Despite the limited resources of nutrition, the parasite grows and generates up to 32 merozoites which are the infectious stages of the complex life cycle. A large part of the intra-erythrocytic development takes place in the so-called parasitophorous vacuole, a compartment which forms an interface between the parasite and the cytoplasm of the host cell. In the course of parasite growth, the host cell undergoes dramatic alterations which on one hand contribute directly to the symptoms of severe malaria and which, on the other hand, are also required for parasite survival. Some of these alterations facilitate the acquisition of nutrients from the extracellular environment which are not provided by the host cell. Here, we describe the cell biologically unique interactions between an intracellular eukaryotic pathogen and its metabolically highly reduced host cell. We further discuss current models to explain the appearance of pathogen-induced novel physiological properties in a host cell which has lost its genetic programme.     

Biopsy histopathology in herpes simplex encephalitis and in encephalitis of undefined etiology.

The histopathology of herpes simplex encephalitis (HSE) has been described principally from postmortem studies which reveal end-stage disease. Biopsy material, which selects an earlier stage in disease development, has been used principally to isolate virus, identify viral particles, and locate viral antigens. Further, little attention has been paid to the histopathology of biopsies of encephalitis of undefined etiology. In the present study, sections from biopsies which yielded virus and those which were negative for virus were evaluated in a systematic and controlled manner. Biopsies yielding virus were characterized by meningeal inflammation, perivascular infiltrates, and glial nodules. Biopsies which did not yield virus and which failed to reveal another diagnosis were characterized by nonspecific gliosis. Thus the early histiopathology of HSE is characterized by early signs of inflammation in the absence of necrosis and generally differs from biopsies in which virus is not isolated.     

Protein export in prokaryotes and eukaryotes. Theme with variations.

Protein export in prokaryotes as well as in eukaryotes can be defined as protein transport across the plasma membrane. In both types of organisms there are various apparently ATP-dependent transport mechanisms which can be distinguished from one another and which show similarities when the prokaryotic mechanism is compared with the respective eukaryotic mechanism. First, one can distinguish between transport mechanisms which involve so-called signal or leader peptides and those which do not. The latter mechanisms seem to employ ATP-dependent transport systems which belong to the family of oligopeptide permeases and multiple drug resistance proteins. Second, in signal or leader peptide-dependent transport one can distinguish between transport mechanisms which involve ribonucleoparticles and those which employ molecular chaperones. Both mechanisms appear to converge at the level of ATP-dependent translocases.     

Drug receptors on single enteric neurons

There are many substances contained within enteric nerves which excite or inhibit other nerves when these substances are applied to single neurons. The actions of these substances and of drugs which mimic these actions is to open or close membrane ion channels. The effects on membrane potential are dependent on the nature of the ions which pass through the channel and whether the channel is opened or closed. In the enteric nervous system, drugs can act at one of three broad classes of receptors: [1] those which are part of an ion channel complex and which open either cation channels or chloride channels, both of which result in membrane depolarization [2] those which open potassium channels resulting in hyperpolarization or [3] those which close potassium channels resulting in depolarization. Receptors which open potassium channels are coupled to the channel via a G-protein while receptors which close potassium channels are coupled to the channel, in some cases, via a cyclic AMP-dependent system while in other cases another second messenger system is involved.     

Simulation of biochemical systems

A computer program has been developed which solves sets of first-order non-linear differential equations which are typical of those encountered in biochemistry. The program includes its own algebraic compiler, which writes the subroutines needed by the integration routine, which is a fourth-order Runge-Kutta process incorporating variable step-length. The routine is simple to use and very fast in operation.     

Preliminary Classification of Viruses Based on Quantitative Comparisons of Viral Nucleic Acids

It is proposed that classifications used in science are of two main types; those which are designed to solve practical problems and which are based on conventions, and those which are designed to solve theoretical problems, based on theories, and in which the classes are tested by experiment. An attempt has been made to construct a preliminary classification of viruses which is of the second type. It is based on the theories of molecular biology, with the use of computer-based comparisons of the molecular weights and base ratios of viral nucleic acids to assign the viruses to clusters which show a high degree of correlation with groupings based on nucleic acid hybridization, serological cross-reactions, and phenotypic properties.     

中华绒螯蟹（Eriocheir sinensis）肌肉中粗脂肪含量与死亡,产 …

本文报道了中华螯蟹越冬时,越冬后不同性别、不同生活状况肌肉中粗脂肪含量及变化。越冬时、越冬后死亡的♂♀河蟹肌肉中粗脂肪的含量均不到８％,而同时越冬成活的♂♀蟹肌肉中粗脂肪含量均高于１０％。顺利越冬并能产卵的雌蟹肌肉中粗脂肪含量为４．９６％,顺利越冬并交配的♂性肌肉中粗脂肪含量为４．１８％。产卵并抱卵孵化的♀蟹肌肉中粗脂肪含量为５．８５％,产卵但♀蟹中途死亡的其肌肉中粗脂肪的含量为５．４７％。交配不     

Purification and Identification of the Fruiting-Inducing Substances in Coprinus macrorhizus

Substances which are effective in inducing fruiting bodies in monokaryotic mycelia of the fis(+) strain of Coprinus macrorhizus were purified and characterized. The active components of fruiting-inducing substances were identified as adenosine-3'-monophosphate, adenosine 3',5'-cyclic monophosphate (cyclic AMP), and a protein which is bound with the cyclic AMP. Cyclic AMP was synthesized from adenine within mycelia of the mutant strains which form monokaryotic fruiting bodies without the addition of fruiting-inducing substances, but not in those of the strains which do not form monokaryotic fruiting bodies. The proteins which bind with cyclic AMP were detected in crude extracts of mycelia of those strains which form monokaryotic fruiting bodies and of the dikaryon, but not in those of the strains which do not form monokaryotic fruiting bodies.     

Thymic dependence of cell-mediated immunity to avian sarcomas in chickens. Immunological characterization of a nonvirion antigen in virus-infected cells.

Chickens bearing tumors which have been induced by avian retroviruses express cellmediated immune responsiveness against antigens which are associated with these neoplasms. We have employed a peripheral lymphocyte stimulation test to characterize antigens which are found in the supernatant fluids of avian retrovirus-infected chicken embryo fibroblast (CEF) cells and in the plasma of birds which have been inoculated with avian myeloblastosis virus (AMV). The results indicated that the antigenic activity being measured was virus group specific, cell transformation independent, and nonvirion in nature. Paradoxically, expression of such antigen(s) was restricted to cells which were actively synthesizing progeny avian retrovirus particles, and was absent in mammalian nonproducer cells which had been transformed by avian sarcoma viruses. Ability to respond immunologically to such antigen(s) was present in animals which had been inoculated with either leukosis or sarcoma viruses. Thymectomy, but not bursectomy, was stimulatory to tumor growth and abolished sensitized lymphocyte immune responsiveness in this system.     

Electroenzymatic reactors with coenzyme regeneration: A theoretical approach

A comparison of the relative performance of production techniques using coenzyme or cofactor electrochemical regeneration demonstrates the superiority of those processes in which the enzymatic reaction and the regeneration are conducted in the same reactor as opposed to those in which the reaction and regeneration are separated. For the former type of reactor, a method of calculation is proposed. This method is based on the solution of equations which describe the phenomena in modules representing three areas: the surface of the electrode, a layer where occur simultaneously the transport of material and the enzymatic reaction, and the bulk of the solution. This method is suggested for three types of reactor: those in which an enzyme solution is held close to an electrode by a semipermeable membrane, those in which an enzyme-charged membrane is in contact with an electrode, and those in which the enzyme is in solution in the vessel into which the electrode is dipped.     

Effect of parity on productivity and sustainability of Lotka–Volterra food chains

Hairston, Slobodkin, and Smith conjectured that top down forces act on food chains, which opposed the previously accepted theory that bottom up forces exclusively dictate the dynamics of populations. We model food chains using the Lotka–Volterra predation model and derive sustainability constants which determine which species will persist or go extinct. Further, we show that the productivity of a sustainable food chain with even trophic levels is predator regulated, or top down, while a sustainable food chain with odd trophic levels is resource limited, which is bottom up, which is consistent with current ecological theory.     

Limitations on the use of and interpretation of data from the Aminco--Chance dual-wavelength split-beam recording spectrophotometer and related instruments.

Problems are discussed which occur during the normal usage of these dual-wavelength, split-beam instruments which can cause serious errors in the derived data and which, when recognized, can be avoided.     

Isolation and characterization of developmental variants in fruiting using a homokaryotic fruiting strain ofCoprinus cinereus

Developmental variants in fruiting ofCoprinus cinereus were induced by mutagenizing oidia of the homokaryotic fruiting strain CopD5-12 with UV light. Through screening of 2,696 isolates, 1,018 strains exhibited defects in fruiting and were classified into 8 groups: (1) knotless variants, which fail to form hyphal knots, the first visible sign of fruiting; (2) primordiumless variants, which form hyphal knots but fail to develop fruit-body primordia; (3) maturationless variants, which form fruit-body primordia but do not form mature fruit bodies; (4) elongationless variants, which form mature fruit bodies with short stipes; (5) expansionless variants, which form mature fruit bodies with unexpanded pilei; (6) sporeless variants, which fail to produce black basidiospores, resulting in fruit bodies with white pilei after maturation; (7) compound type, which includes variants exhibiting several of the phenotypes described above; (8) others, including variants that produce a “dark stipe” even under in light/dark conditions, which is formed under continuous darkness in the wild-type. Two elongationless variants were characterized histologically.     

The isolation and genetic characterization of X-linked mutations that affect pyrimidine metabolism in Drosophila melanogaster

Summary This paper focuses on the number of X-linked genes which play a role in pyrimidine metabolism. A series of mutation screens have been carried out for the following types of mutants: (a) mutants which reduce pyrimidine synthesis, (b) mutants which reduce pyrimidine catabolism, and (c) mutants which are unable to utilize dietary pyrimidines and depend upon de novo synthesis for survival. The genetic characterization of the 95 X-linked mutants obtained indicates that there are very few X-linked genes which play a direct role in pyrimidine metabolism.