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PRIMARY EVENTS OCCURRING IN PHOTOINHIBITION IN SYNECHOCYSTIS-6714 WILD-TYPE AND AN ATRAZINE-RESISTANT MUTANT

BIOCHIMICA ET BIOPHYSICA ACTA 1990年第1期1020卷 87-93页

作者： KIRILOVSKY, D DUCRUET, JM ETIENNE, AL INRA CEA DEPT BIOL SERV BIOPHYS GIF SUR YVETTE FRANCE

Exposure of photosynthetic organisms to a light intensity higher than that needed to saturate photosynthesis causes the inhibition of Photosystem II activity (photoinhibition). We induced photoinhibition in cells of Synechocystis 6714 strains by exposure to light intensities between 1000 and 4000 .mu.E.m.-2.s-1. fluorescence, thermoluminescence and oxygen measurements were used to follow the inhibition of electron transfer in Photosystem II centers. We demonstrated that, in oxygen evolving Photosystem II centers, the electron transfer from QA to QB was not slowed down. Photoinhibited samples presented a normal oscillation pattern of oxygen yield. The rate of deactivation of S2 state was similar in control and photoinhibited cells. This indicates that the QA/QB equilibrium is not modified in the centers which evolve oxygen. By studying the kinetics of the decrease of the amplitudes of the thermoluminescence Q and B bands in Synechocystis 6714 we confirmed our previous conclusions drawn from electron transfer measurements: the inhibition of electron transfer to QB is faster than the inhibition of electron transfer to QA. We conclude that a succession of two different states of Photosystem II centers is produced during the process of photoinhibition: (1) A state in which the electron transfer is inhibited between QA and QB. (2) an inactivated low fluorescent state where QA- formation is also inhibited. Restoration of the photoactive fluorescent Photosystem II requires de novo synthesis of D1. Our main conclusion is that the first damage during photoinhibition in cyanobacteria cells is at the level of the QA to QB electron transfer step.

关键词： Photoinhibition Cyanobacterium Photosystem II D 1 protein ( Synechocystis 6714) Chl chlorophyll D 1 and D 2 polypeptides of the RCII DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea f 0 , f v initial variable fluorescence f max maximum fluorescence P680 the chlorophyll molecule which acts as the primary electron donor in the RCII PS II Photosystem II Q A primary quinone electron acceptors Q B secondary quinone electron acceptors RCII reaction center II

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EXCITATORY AMINO-ACID NEUROTOXICITY AND NEURODEGENERATIVE DISEASE

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TRENDS IN PHARMACOLOGICAL SCIENCES 1990年第9期11卷 379-387页

作者： MELDRUM, B GARTHWAITE, J UNIV LIVERPOOL DEPT PHYSIOL LIVERPOOL L69 3BX ENGLAND

The progress over the last 30 years in defining the role of excitatory amino acids in normal physiological function and in the abnormal neuronal activity of epilepsy has been reviewed in earlier articles in this series. In the last five years it has become clear that excitatory amino acids also play a role in a wide range of neurodegenerative processes. The evidence is clearest where the degenerative process is acute, but is more controversial for slow degenerative processes. In this article Brian Meldrum and John Garthwaite review in vivo and in vitro studies of the cytotoxicity of amino acids and summarize the contribution of such toxicity to acute and chronic neurodegenerative disorders.

关键词： AP5 2-amino-5-phosphonopentanoate AP7 2-amino-5-phosphonoheptanoate CNQX 6-cyano-7-nitroquinoxaline-2,3-dione CPP 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid CPPene 3-(2-carboxypiperazin-4-yl)-1-propenyl-1-phosphonic acid DNQX 6,7-dinitroquinoxaline-2,3-dione HA966 1-hydroxy-3-amino-pyrrolidin-2-one NBQX 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo[ f ]quinoxaline PCP phencyclidine TCP 1-1-(2-thienyl)cyclohexyl piperidine SL820715 (±)-α-(4-chlorophenyl)-4-[(4-fluorophenyl)methyl]-1-piperidine ethanol

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IS CYTOCHROME P-450SCC A TRANSMEMBRANE PROTEIN

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fEBS LETTERS 1990年第1-2期275卷 33-35页

作者： USANOV, SA CHERNOGOLOV, AA CHASHCHIN, VL Protein Chemistry Laboratory Institute of Bioorganic Chemistry BSSR Academy of Sciences Minsk USSR

The topology of cytochrome P-450 scc in the inner mitochondrial membrane of adrenal cortex has been investigated using monospecific antibodies to cytochrome P-450 scc and its fragments f 1 (Ile 1 -Arg 250 ), f 2 (Asn 257 -Ala 481 ) and f 3 (Asn 257 -Arg 399 ). Antibodies to f 1 and f 2 were shown to effectively bind to the matrix and cytosolic sides of the inner membrane. Antibodies to f 3 specifically interacted only with the matrix side of the membrane. These data are consistent with a model of molecular organization which shows that cytochrome P-450 scc is a transmembrane protein, both N- and C-terminal sequences of the cytochrome being able to span the membrane.

关键词： Cytochrome P-450 scc fragment Monospecific antibody Membrane topology Bovine adrenal cortex P-450 scc and P-450 11β bovine adrenocortical cytochromes P-450 scc and P-450 11b f 1 , f 2 and f 3 fragments of P-450 scc polypeptide chain PB sodium phosphate buffer

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NA+-COUPLED ATP SYNTHESIS IN PROPIONIGENIUM-MODESTUM - IS IT A UNIQUE SYSTEM

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BIOCHIMICA ET BIOPHYSICA ACTA 1990年第2-3期1018卷 206-210页

作者： HOffMANN, A LAUBINGER, W DIMROTH, P TECH UNIV MUNICH INST PHYSIOL CHEMW-8000 MUNICH 2GERMANY

The ATPase of Propionigenium modestum is an enzyme of the f1f0 type, which uses Na+ (or H+ at low Na+ concentrations) as the coupling ion. A hybrid ATPase constructed from f1 of Escherichia coli and f0 of P. modestum had the same cation-coupling specificity as the homologous P. modestum ATPase. The ATPase of Bacillus alcalophilus is an f10-Type ATPase that pumps protons specifically and is unable to catalyze Na+ translocation.

关键词： ATPase, f 1 f 0 - Proton translocation Sodium ion translocation ( B. alcalophilus ) ( P. modestum ) ACMA 9-amino-6-chloro-2-methoxyacridine CCCP carbonyl cyanide m -chlorophenylhydrazone

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A STUDY ON XINGKAI LAKE PINE GALL RUST

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Journal of Northeast forestry University 1990年第1期1卷 65-71页

作者： Shao Liping (1) Xuc Yu (1) Wang Zhcnhua (2) 1. Northeast Forestry University 150040 Harbin China 2. Mishan Forest Bureau Mishan County Heilong jiang

The xingkai Lake pine(Pinus lakahasii Nakai) gall rust caused by Cronartiumquereuum(Berk.)Miyabe:Shirai is a serious stem rust in the northeast region of *** alternatehost is oak (Quercus mongolica fisch).Germination of both acciospores and urediospores wasoptimal at 12℃ and occurred over a range of temperatures,from 4℃ to 32℃.Teliosperes germinatedoptimally at 16--18℃ and over a range of 8--28℃.All spores germinated best under natural light anddark *** light inhibited germination eren when followed by *** incubauonperiods of urediospores and teliospores in inoculation experiments were 6--16 days and 3--33daysrespectively. Anatomical studies of Cribartium quercuum galls showed that rust hyphae freely ramify throughthe intereellular spaces within parenchymatous lissues of the cortex,phloem,cambium,and xylemHyphac are perennial;largc haustoria are cylindrical with rounded or blunt ends. Among the 12 fungieides tested for control the rust,pine-tar,pine-tar;diesel oil(1:1。

关键词： Xingkal Lake pinc Gall rust. Disease f ungicide Cronartium quercuum

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UNISITE ATP SYNTHESIS IN THYLAKOIDS

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fEBS LETTERS 1990年第1-2期271卷 116-118页

作者： LABAHN, A fROMME, P GRABER, P UNIV STUTTGART INST BIOLW-7000 STUTTGART 80GERMANY

Uni-site ATP synthesis was measured with thylakoids. The membrane-bound ATP-synthase, Cf 0 f 1 was brought into the active, reduced state by illumination in the presence of thioredoxin, dithiothreitol and phosphate. This enzyme contains two tightly bound ATP per Cf o f 1 . ATP was released from the enzyme when ADP was added in substoichiometric amounts during illumination. Experiments with [ 14 C]ADP indicated that after binding the same nucleotide was phosphorylated and released as [ 14 C]ATP, i.e. only one site is involved in ATP-synthesis (uni-site ATP-synthesis'). The two tightly bound ATP are not involved in the catalytic turnover. The rate constant for ADP binding was (4 ± 2) × 10 6 M −1 s −1 . Compared to deenergized conditions the rate constant for ADP binding and that for ATP-release were drastically increased, i.e. membrane energization increased the rate constants for the ATP-synthesis direction.

关键词： Chloroplast ATPase H + Cf 0 f 1 Uni-site catalysis ATP synthesis Cf 0 f 1 H + -translocating ATPase (‘ATP-synthase’) from chloroplasts

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Prime contract competition regimes and subcontracting among military aircraft manufacturers

Prime contract competition regimes and subcontracting among ...

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作者： Alexander, Barbara J. Harvard University

学位级别：Ph.D.

This dissertation explores the ability of prime defense contractors to sustain bidding cartels under two different Pentagon competition regimes. The existence of information flows from the Pentagon to contractors regarding bids of competing firms suggests that collusion may be easier to sustain in "paper" competitions than in "prototype" competitions. The difficulty of revising "bids" which consist largely of physical prototypes makes maintenance of collusive agreements much more difficult in prototype competitions. Moreover, a positive profit, non-collusive equilibrium is more likely to exist in prototype competitions, due to technological uncertainty regarding the returns to expenditure on prototypes. A correlation is found between rivalry in paper competitions and the number of subcontracting links between pairs of aircraft manufacturers, suggesting that subcontracts may be used as vehicles for side-payments associated with collusive bidding. An alternative "technical efficiency" hypothesis of subcontracting awards is explored, using patent data and annual report data to evaluate production cost determinants of aircraft subcontractors. A history of "paper" prime contract bidding relationships is found to be a primary determinant of subcontract awards to other aircraft manufacturers. The number of employees per patent shows a moderate (although statistically insignificant) negative correlation with subcontract awards to radar manufacturers, but a much weaker correlation with awards to other aircraft manufacturers. It is concluded that subcontract awards are likely to be driven at least to some extent by inter-firm side-payments, but that the role of technical efficiency considerations is yet to be determined.

关键词： S o c i a l s c i e n c e s , c o n t r a c t o r s , a i r c r a f t m a n u f a c t u r i n g

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The "classical" monetary theories of Marshall,Wicksell,and Keynes and the General Theory's critique: Equilibrium,price trends,and cycles

The "classical" monetary theories of Marshall,Wicksell,and K...

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作者： Gaynor,William Beryl,Jr McGill University

学位级别：Doctor

We first demonstrate the importance of the doctrines of the quantity theory and the long-period stationary state in the formulation of Marshall's,Wicksell's,and Keynes' pre-General Theory monetary theories. We analyze the anomalous events characterized by these writers as short-period phenomena. from the perspective built up around the quantity equation and its long-period context,business cycles represent economic convolutions in which the behavioral mechanisms of the long-period break down. We demonstrate the theoretical breakdown;importantly,it is not reflected in the work of these writers that they understood that their explanations of short-period events undermined the long-period theorizing they carefully built. Second,it is argued that Keynes saw the General Theory as a theory of the short-period in contrast to the long-period monetary frameworks. We use the General Theory's criticisms of classical monetary theory to establish this point.

关键词： S o c i a l s c i e n c e s , M a r s h a l l , A l f r e d , W i c k s e l l , K n u t , K e y n

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In-class microcomputer health and safety assessment among Tennessee third, fourth and fifth-grade students

In-class microcomputer health and safety assessment among Te...

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作者： Obersaat, Ruth C. The University of Tennessee

学位级别：Ed.D.

The purpose of the study was to design and develop an inclass microcomputer program to identify health and safety risk factors of children attending selected Tennessee public schools as third, fourth or fifth graders during the school year 1989-90, and to provide baseline data to address whether significant differences exist among grade-, gender-, race-, and geographic-specific populations. The data were collected using the inclass computer program entitled: The Tennessee School Health and Safety Profile. The sample consisted of 986 third, fourth and fifth grade students from 16 selected Tennessee public schools. Descriptive statistics were used to obtain frequencies and percentages of the sample according to grade, gender, race, and geographical area. The major findings of the study included: (1) The majority (39.3%) of Tennessee third, fourth and fifth grade students were categorized into the fair health and safety risk category; (2) The results of cross tabulations of grade, gender, and geographic area with the health and safety risk categories were significant but were not significant for race; (3) Significant differences were found in the practice of risky health and safety behaviors according to grade, gender, and geographical area; however no significant difference was determined between nonwhite and white students; (4) The major health and safety risk factors among Tennessee school-age children were inability to swim, feeling life was not worth living, lack of supervision at home, poor dental hygiene habits, fear of the AIDS virus, lack of proper home fire safety, poor nutrition habits, watching television six or more hours a day, carrying a knife, lack of adequate exercise, and lack of seatbelt use. The following conclusions were drawn: (1) The overall health and safety of Tennessee's school-age children is fair; (2) As students progress in grade, their practice of risky health and safety behavior increases; (3) The race of the students seems not to be a fa

关键词： S o c i a l s c i e n c e s , E d u c a t i o n , t h i r d - g r a d e , f o u r t h - g r a d e

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Role of environmental, organizational and technological factors in information technology implementation in advanced manufacturing: An innovation adoption-diffusion perspective

Role of environmental, organizational and technological fact...

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作者： Ramamurthy, Keshavamurthy University of Pittsburgh

学位级别：Ph.D.

The "factory of the future," with computer-based information-intensive advanced manufacturing technologies (AMT) has been increasingly prescribed as a potential solution to prevent the decline of the U.S. as a world leader in manufacturing. A number of factors--environmental, structural, technological, individual, and task-related--in a firm's operating environment can facilitate or inhibit the adoption, implementation and successful management of these manufacturing innovations. Synthesizing the research in three major domains--Information Systems implementation, Organizational Innovation, and Strategic Adaptation--this dissertation (1) proposes a four stage innovation adoption-diffusion model; and (2) empirically validates a major portion of the model by examining the influences of the organization's external environment, internal environment and technological factors on the initiation and adoption of these technological innovations. Building on past research, this study identifies twelve factors--the perceived dynamism, complexity and hostility of the external environment, centralization, formalization, organizational complexity, organizational past attitude and organizational slack, compatibility, complexity, costs and the relative advantage of the AMT as important determinants of the organizational innovative process and examined their effects. It uses in "approximately longitudinal" (retrospective collection of time series type data) research design consisting of field survey for data gathering from firms in a number of industries using a structured, mailed questionnaire. Through bivariate correlational and multivariate regression analyses, the results demonstrated that while all the external and internal environmental and technological factors exerted significant influences, only environmental complexity and hostility, the organizations' surplus resources and the relative advantage possessed by the AMT innovations emerged as significant predictors of the moti

关键词： S o c i a l s c i e n c e s , O r g a n i z a t i o n a l f a c t o r s , E n v i r o n m e n t

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