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1.
Between 1984 and 1996, public health authorities in Israel maintained a secret policy of discarding blood donations made by Ethiopian-Israeli citizens and immigrants. Officials later attempted to justify this policy on the grounds that immigrants from Ethiopia were subject to high rates of infectious disease (especially HIV). In 1996, this led to an explosive and violent confrontation between Ethiopian-Israeli protestors and agents of the state, including police and public health authorities. This essay explores the cultural and political context of that confrontation, including the discourse of political violence which it occasioned. The conflict between Ethiopian-Israelis and the state was located within a wider set of political contexts, including the Israeli-Palestinian conflict, which was linked to it through a shared trope of spilled blood common to both. Cultural analyses which ignore this dynamic political context are in danger of seriously misrepresenting the meaning of the Blood Affair to its participants. At the same time, this essay also engages a critical analysis of the public health policies which led to the crisis. Public health and nationalist discourse reinforced one another at the expense of Ethiopian immigrants in general, and so-called Feres Mura Ethiopians in particular.  相似文献   

2.
E. Schnepf 《Protoplasma》1984,120(1-2):100-112
Summary The microtubules (MTs) of developingSphagnum leaflets rearrange from the interphase array into the preprophase band without obvious participation of definite initiation sites. At late prophase, additional MTs appear along the nuclear envelope, with the same orientation as in the peripherally situated preprophase band. Spindle formation begins along the nuclear envelope; spindle MTs run perpendicular to preprophase band MTs and converge in several focus points with indistinct polar bodies. After cytokinesis, most spindle and phragmoplast MTs disappear. Interphase MTs reappear at first along the central part of the new cell wall, in a region which was occupied before by the initial phragmoplast; their orientation is perpendicular to the phragmoplast MTs. Also here, distinct MT organizing centers could not be observed. Then the MT spread out over the cell periphery. The observations suggest that diffuse MT organizing zones rather than definite MT organizing centers play a role in the rearrangement of the different MT arrays during the cell cycle.  相似文献   

3.
The psychological side effects of self-regulatory treatment (a combination of relaxation, thermal biofeedback, and cognitive therapy) for irritable bowel syndrome (IBS) were compared among 20 successfully treated patients, 12 unsuccessfully treated patients, and 9 patients who merely monitored symptoms for 12 weeks. Pretreatment and posttreatment scores on the Beck Depression Inventory, State-Trait Anxiety Inventory, and Psychosomatic Symptom Checklist were examined. Successfully treated patients had significant (p<.01) reductions on all measures and significantly greater reductions on depression and state anxiety than the symptom monitoring group. Interestingly, the failures also showed a significant (p=.027) reduction in trait anxiety and no significant increases on other measures.  相似文献   

4.
Neurosteroids are endogenous Central Nervous System (CNS) compounds which act mainly by allosteric modulation of the GABAA receptor complex. The presence of a 3-hydroxyl group and a 5-hydrogen atom have been found to be essential structural requirements for biological activity in mammals. In the present work we report the enhancing activity on [3H]GABA binding to its receptor sites in chick optic lobe produced by progesterone metabolites 3-hydroxy,5-pregnan-20-one (3,5-P) and 3-hydroxy,5-pregnan-20-one (3,5-P). Both steroids were found able to enhance [3H]GABA binding along ontogeny, displaying a similar profile at early developmental stages, while in adulthood 3,5-P had greater potency (EC50 0.22 M) and enhancing effect (Emax: 122%). In adult synaptic membranes, the two compounds displayed a complex interaction with the GABAA receptor, disclosed by a Schild plot with slope below one and an incomplete displacement of 3,5-P by its 3,5 isomer. Such complexity could be related to the steroidogenic profile in avian CNS, with 5-reduced progesterone metabolites present since early development, while 3,5-P is found only in adulthood. Bearing in mind differences between avian and mammalian steroidogenic profiles and the relevance of 5-steroids in early avian development, we propose that 3,5-P, instead of the classical potent 3,5-steroids, may be the endogenous modulator of GABAergic activity in developing avian brain.  相似文献   

5.
In southern and south-western Ethiopia, Ensete ventricosum is grown as an important starchy, staple food crop, supporting the diet of a quarter of the Ethiopian population. Due to difficulty in germinating seeds and the long vegetative period, breeding enset is extremely difficult. Adventitious buds and somatic embryos have been induced from callus derived from corm tissues and cultured on Murashige and Skoog's (MS) basal medium supplemented with benzylaminopurine (BAP) or 6 --dimethylallylamino purine 2iP. Elongation of somatic embryos was achieved on the same medium and rooting was induced on half-strength MS basal medium supplemented with IBA. No phenotypic variation was observed among more than 200 potted regenerants. The possible implications for mutation breeding in this crop are discussed.Abbreviations IAA Indole-acetic acid - IBA Indole-butyric acid - BAP Benzylaminopurine - 2iP 6 --dimethylallylamino purine  相似文献   

6.
Contrary to other reports, we have found that the A type G6PD found in two permanent cell lines—HeLa (Gey), with its single cell clonal derivative HeLa S3, and Detroit 98, with its four clonal derivative lines—is not a single variant but rather at least three different isozymes. One is heat stable with normal specific activity and normal A type electrophoretic migration, another is heat labile with normal specific activity and normal A type electrophoretic migration, and the third is heat labile with reduced specific activity and slightly slow A type electrophoretic migration. We also found that in a mosaic cell population with respect to G6PD phenotype, the predominant G6PD phenotype varied randomly over a 5-month period, that the G6PD phenotype might be mutable in permanent cell lines, and that spontaneous human cell lines might not be HeLa cell contaminants as has been suggested.Aided by the National Institutes of Health General Research Support Grant # 5 S01 FR05507.  相似文献   

7.
The main contribution of this paper is to propose a new cluster maintenance algorithm and a companion cluster initialization algorithm based on a number of interesting and novel properties of diameter-2 graphs. The initialization algorithm naturally blends into cluster maintenance, showing the unity between these two operations. We refer to our algorithms as tree-based since they depend on a spanning tree maintained at various nodes. Unlike the vast majority of published clustering algorithms, our algorithms are cluster-centric, as opposed to node-centric, and work in the presence of node mobility. Extensive simulation results have shown the effectiveness of our algorithms when compared to other clustering schemes proposed in the literature.Lan Wang received his B.S. and M.S. degrees in computer science from Harbin Engineering University, China in 1992 and 1995, respectively. From 1995 to 1999, he worked as a software engineer at the System Engineering Research Institute of CSSC, Beijing, China. He is currently a PhD student at the Computer Science Department of Old Dominion University.Stephan Olariu received the M.Sc. and Ph.D. degrees in computer science from McGill University, Montreal, Canada in 1983 and 1986, respectively. In 1986 he joined the Computer Science Department at Old Dominion University where he is now a full professor. He has published extensively in various journals, book chapters, and conference proceedings. His research interests include wireless networks and mobile computing, parallel and distributed systems, performance evaluation, and medical image processing. Prof. Olariu serves on the editorial board of several archival journals including IEEE Transactions on Parallel and Distributed Systems, Journal of Parallel and Distributed Computing, International Journal of Foundations of Computer Science, Journal of Supercomputing, International Journal of Computer Mathematics, VLSI Design, and Parallel Algorithms and Applications.  相似文献   

8.
Zusammenfassung Die beschriebenen experimentellen Befunde zeigen, daß die höhere Pflanze grundsätzlich in der Lage ist, organische Verbindungen aus dem Wurzelraum (Rhizosphäre) aufzunehmen, diese als Zwischenprodukte nutzt und in ihr biochemisches Zellgeschehen einschleust. Die organische Substanz (Humus) in natürlichen Standorten bietet somit unter Umständen vielfältige Möglichkeiten des direkten Einflusses organischer Verbindungen auf das Stoffwechselgeschehen der höhere Pflanze. Hier bieten sich eventuell auch Möglichkeiten, die Ausbildung von Ökotypen auf dieser Basis zu deuten.Mixotrophie der höheren Pflanze bedeutet also eine noch stärkere Verflechtung des Bio-Geo-Systems Pflanze-Boden und stellt den klassischen Begriff des Nährhumus unter einen neuen organodynamischen Gesichtspunkt.
Summary The experimental results described above show, that the higher plant can take up organic compounds from the rhizosphere and utilize them in cell metabolism.Thus another type of chemical interaction between plant and the organic matter of soil is existing, by which the close integration of the bio-geosystem plant and soil can be demonstrated and a modern view of the classical concept of the nutritional functions of humus can be given.
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9.
MHC class I molecules are heterotrimeric complexes composed of heavy chain, 2-microglobulin (2m) and short peptide. This trimeric complex is generated in the endoplasmic reticulum (ER), where a peptide loading complex (PLC) facilitates transport from the cytosol and binding of the peptide to the preassembled ER resident heavy chain/2m dimers. Association of mouse MHC class I heavy chain with 2m is characterized by allelic differences in the number and/or positions of amino acid interactions. It is unclear, however, whether all alleles follow common binding patterns with minimal contributions by allele-specific contacts, or whether essential contacts with 2m are different for each allele. While searching for the PLC binding site in the 3 domain of the mouse MHC class I molecule H-2Db, we unexpectedly discovered a site critical for binding mouse, but not human, 2m. Interestingly, amino acids in the corresponding region of another MHC class I heavy chain allele do not make contacts with the mouse 2m. Thus, there are allelic differences in the modes of binding of 2m to the heavy chain of MHC class I.  相似文献   

10.
The conformational properties of the oligosaccharide chain of GM1 ganglioside containingN-glycolyl-neuraminic acid, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer, were studied through NMR nuclear Overhauser effect investigations on the monomeric ganglioside in dimethylsulfoxide, and on mixed micelles of ganglioside and dodecylphosphocholine in water. Several interresidual contacts for the trisaccharide core--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-were found to fix the relative orientitation of the three saccharides, while the glycosidic linkage of the terminal -Gal-was found to be quite mobile as the -Gal-(1-3)--GalNAc-disaccharide exists in different conformations. These results are similar to those found for two GM1 gangliosides containingN-acetyl-neuraminic acid and neuraminic acid [1].Abbreviations Ganglioside nomenclature is in accordance with Svennerholm [23] and the IUPAC-IUB Recommendations [24] GM3(Neu5Ac) II3Neu5AcLacCer, -Neu5Ac-(2-3)--Gal-(1-4)--Glc-(1-1)-Cer - GM3(Neu5Gc) II3Neu5GcLacCer, -Neu5Gc-(2-3)--Gal-(1-4)--Glc-(1-1)-Cer - GM1(Neu5Ac) II3Neu5AcGgOse4Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer - GM1(Neu5Gc) II3Neu5GcGgOse4Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer - GM1(Neu) II3NeuGgOse4Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu-(2-3)]--Glc-(1-1)-Cer - GD1a IV3Neu5AcII3Neu5AcGgOse4Cer, -Neu5Ac-(2-3)--Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer - GalNAc-GD1a IV4GalNAcIV3Neu5AcII3Neu5AcGgOse4Cer, -GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer - Neu neuraminic acid - Neu5Ac N-acetyl-neuraminic acid - Neu5Gc N-glycolyl-neuraminic acid - Cer ceramide  相似文献   

11.
Concentrations of Al, Fe, Mn, Cd, Cu, Pb, and Zn were measured in thereference and treatment basins of Little Rock Lake (Vilas County, Wisconsin), alow-alkalinity, seepage system (pH 6.1, alkalinity25eq/L) during six years of a whole-basinacidificationand the first four years of the lake's recovery. The treatment basin wasacidified with H2SO4 in three two-year steps to pH5.6, 5.1, and 4.7. By the end of year 4 of recovery, treatmentbasin pH increased to 5.3 as a result of internal alkalinity generation.During acidification, dissolved Mn and Fe (0.4mpore-size filters) increased at pH 5.6; dissolved Al, Cd, and Zn becameelevated at pH 5.1; and dissolved Pb at pH 4.7. Dissolved Cu remainedsimilar in both basins to pH 4.7. Al, Fe and Mn levels declinedsignificantly during the recovery period, approaching values at pH 5.3intermediate between the concentrations at pH 5.6 and 5.1 during acidification.Dissolved Al and Fe in the reference basin were near the equilibrium levels forsolubility of gibbsite (Al(OH)3) and amorphousFe(OH)3(s).The acidified basin was undersaturated relative to gibbsite, and dissolved Alwas limited by pH disequilibrium between the water column and sediments andpossibly by Al-DOC precipitation. Dissolved Fe apparently was controlled bysolubility of amorphous Fe(OH)3(s) and Fe-DOC precipitation.Dissolved Mn levels in both basins were consistent with manganite[-MnOOH(s)] solubility. Elevated levels of Cd, Pb, and Zn in thetreatment basin during acidification probably resulted from less efficientscavenging of atmospherically-deposited Cd, Pb, and Zn by settling particles.  相似文献   

12.
A levansucrase (SacB) of Zymomonas mobilis was purified to electrophoretic homogeneity from a recombinant Escherichia coli. The 55 kDa enzyme hydrolysed -fructosides but not -glucosides and catalysed levan formation from sucrose as well as raffinose. The optimum temperature for polymerase activity (30°C ) was lower than that for hydrolase activity (50°C ). In contrast to other levansucrases, polymerase activity of levansucrase was inhibited by para- chloromercuribenzoate (1 mM) but with little or no effect on hydrolase activity. Selective modulation of polymerase activity by this inhibitor will be useful in revealing the mechanism of levansucrase catalysis.  相似文献   

13.
Summary We have studied 105 individuals in the village of Jasser El Zarka in the Northern Coast of Israel of whom 59% had at least one abnormal hemoglobin. Of the individuals studied 41% were AA, 13.3% AS, 28.6% AOArab, 10.5% SOArab, 0.9% SS, 38% Arab-+ Thal, and 1.9% Thal trait. The SOArab double heterozygotes were characterized by a normal mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC), and an increase of Hb F (11.7±4.3%) and 2,3-diphosphoglycerate levels (27.8 m/g Hb). The increase of Hb F is higher than the one seen among OArabs of other ethnic backgrounds. Their clinical course was moderately severe and osteoporosis was quite frequent. The interactions of Hb OArab and Hb S were studied in vitro and it was confirmed the Hb OArab lowers the minimal gelling concentration of mixtures with Hb S (as compared to mixtures of Hb S and Hb A), but that this effect is ionic-strength dependent. Our data are in conflict with previous claims that Hb OArab mixtures with Hb S polymerized almost as much as pure S. Oxygen association curves show a significant displacement of the p50 to the right, but the effect of oxygen dissociation is less apparent. The displacement was not nearly as significant as with SS cells, confirming our gelation data. Blood group determinations establish that these Arab populations had black African admixture.The Hb OArab/+ Thal double heterozygotes exhibit moderate anemia (10.3g% of Hb) and the percentage of Hb A was 17.2±1.8%. The fetal Hb was 5.4±2.1% and the 2,3-diphosphoglycerate level in two cases was 17.4 mol/g Hb. The only case of a homozygote SS had moderate anemia (10.3 g Hb%), 25.7% of Hb F, and a very benign course.  相似文献   

14.
Flax anther culture: effect of genotype,cold treatment and media   总被引:2,自引:0,他引:2  
We report on screening of wide range of flax cultivars for androgenic response and on testing of induction conditions for flax (Linum usitatissimum L.) anther culture and plant regeneration. Anthers were cultured on four different media: Mo, N6, MS and N&N supplemented with various combinations of growth regulators. The induction of callus formation from cultured anthers was the highest on N6 (with cultivar PR FGL 77 – 12 %) and N&N media (with cultivar Carolin – 2.8 %), preferentially after cold pretreatment (7days at 8 °C). Shoots were formed on calli derived from the microspores inside the cultured anthers on media N&N and N6 supplemented with 1mgl–1 zeatin or 1mgl–1BAP + 1mgl–1NAA, respectively and elongated on MS medium supplemented with 2mgl–1 zeatin. The highest number of shoots (120) was observed with cultivar Red Wing. Shoots were rooted on MS medium supplemented with 2mgl–1IAA. Our experiments resulted in total in 62 % anther response and 155 plants regenerated and transferred into soil.  相似文献   

15.
Summary The histochemical activities of succinic dehydrogenase (SDH), myofibrillar Adenosine triphosphatase (ATPase) and alpha glycerophosphate dehydrogenase were studied in serial sections of rat vastus lateralis (red) (RVL), gastrocnemius and diaphragm muscles. Three main fibre-types were distinguished. The Type I fibres of RVL and gastrocnemius muscles fell into two distinct groups: one category-Type IA showed very low ATPase activity. The second category of Type IB fibres displayed moderate ATPase reaction. The Type IA fibres were divisible into two sub-groups when tested for SDH reaction. Type IA1 fibres possessed a homogenous distribution of diformazan·granules throughout the fibre: Type IA2 fibres displayed characteristic moth-eaten pattern of diformazan localization. The diaphragm muscle did not show either Type IB or Type IA2 varieties. The great majority of Type I fibres were sub-type IA1 in the three fast muscles studied. It is also demonstrated here that an inherent heterogeneity exists between Type I fibres of diaphragm and leg muscles in regard to -GPD localization. This histochemical data emphasizes the fact that subdivision of Type I striated muscle fibres of mammalian animals into two sub-types is only approximate and that a further subcategorization is possible.  相似文献   

16.
This study reports a novel splice variant form of the voltage-dependent calcium channel 2 subunit (2g). This variant is composed of the conserved amino-terminal sequences of the 2a subunit, but lacks the -subunit interaction domain (BID), which is thought essential for interactions with the 1 subunit. Gene structure analysis revealed that this gene was composed of 13 translated exons spread over 107 kb of the genome. The gene structure of the 2 subunit was similar in exon-intron organization to the murine 3 and human 4 subunits. Electrophysiological evaluation revealed that 2a and 2g affected channel properties in different ways. The 2a subunit increased the peak amplitude, but failed to increase channel inactivation, while 2g had no significant effects on either the peak current amplitude or channel inactivation. Other subunits, such as 3 and 4, significantly increased the peak current and accelerated current inactivation.  相似文献   

17.
Microdissected Deiters' neuron plasma membranes have been used for studying the passage of GABA through the membrane both in the inward and outward direction. Working with 0.2 mM GABA in the compartment simulating the outside of the neurone and with 2.0 mM GABA in the one simulating the inside we found a net transport of GABA towards the inside. This mechanism does not require a Na+ ion gradient across the membrane. The nature of the transport process involved was studied by determining the rate of [3H]-GABA inward passage as a function of GABA concentration (1 nM–800 M) on the outward side of the membrane. The results have shown that until 50 M a diffusion process (v=D1×C, where D1=3.1×10–11 1/m2×sec) is the sole mechanism involved. Above 50 M a second diffusion process is activated v=D2×(C–50×10–6), where D2=2.8×10–11 1/m2×sec. Taking in account both inward and outward directed diffusion, one can calculate 16 M as the equilibrium concentration of GABA on the outward side of the membrane. From a kinetic point of view, these diffusion processes are able to reduce GABA concentration in a synaptic cleft from 3 mM to 20 M within 3 sec. These diffusion systems are discussed as extremely efficient in removing the excess of released GABA in the synaptic cleft.  相似文献   

18.
Zusammenfassung In zunehmendem Maße werden anisoploideBeta-Rübensorten angebaut, deren zytologische Kontrolle zwecks Feststellung der Genomstufenprozentanteile recht arbeitszeitaufwendig ist. Übereinstimmend mit polnischen Autoren wurde festgestellt, daß die Hypokotylfarbe ein geeigneter Markierungsfaktor für die einzelnen Genomstufen darstellt. Kreuzt man tetraploide Pflanzen, die ein grünes Hypokotyl besitzen, mit diploiden Pflanzen, die ein rosa Hypokotyl aufweisen, so erhält man von dem tetraploiden Partner tetraploide grüne und triploide hellbraune, von dem diploiden Partner diploide rosa und triploide hellbraune Nachkommenschaften. Die in bezug auf die Hypokotylfarbe heterozygoten Pflanzen kann man demnach von den homozygot grünen und homozygot rosa Individuen unterscheiden. Die Kreuzung diploid grünxtetraploid rosa ist für diese Zwecke nicht brauchbar, da sich die triploiden Heterozygoten mit einem grünen und zwei rosa Allelen in der Hypokotylfarbe nicht deutlich von den homozygoten rosa Pflanzen abheben. Auf die Bedeutung dieser Markierungsmöglichkeit für bestimmte Forschungsprobleme, die Züchtung und die Saatgutkontrolle wird hingewiesen.  相似文献   

19.
Résumé G. mellonella infestée au dernier stade larvaire avec 1, 2, 3 ou 5 planidia/hôte (ph/H) produit 1 à 5 pupes/hôte (pu/H). La mortalité des chenilles augmente avec le nombre de pl/H. Le poids des pupes et décroît avec un nombre croissant de pu/H (18,2 à 12,9 mg pour les et 12,5 à 9,7 mg pour les ). Le développement larvaire dure 8,7 j. chez les et 8,3 chez les ; il est peu affecté par le superparasitisme. Avec 1, 2, 3 et 5 pl/H nous obtenons 0,84–1,61–2,17 et 3,43 pu/H et 0,81–1,48–2,10 et 3,11 imagos/H. L'optimum est de 3 pl/H ou 1 à 2=pl/H pour obtenir des parasitoïdes plus lourds.
Summary The influence of superparasitism on larval and pupal development is investigated. Last-larval instar G. mellonella (200±5 mg) were infected with 1, 2, 3 or 5 planidia/host (pl/H) producing 1 to 5 pupae per host (pu/H). Host mortality (8.6–8.3–14.3 and 22.2%) increased with the number of planidia. The planidia may transmit a bacteriosis. Pupal weight ( and ) decreased as number of pu/H increased. pupae were heavier than ones: 12.9 to 18.2 mg for against 9.7 to 12.5 mg for . Larval development lasted slightly longer for (8.7 d.) than for (8.3 d.), and its duration was little affected by superparasitism. 1, 2, 3 or 5 pl/H yielded 0.84–1.61–2.17 and 3.43 pu/H and 0.81–1.48–2.10 and 3.11 adults/H. An optimum was obtained with 3 planidia of L. diatraeae on G. mellonella or 1 to 2 to obtain heavier parasitoids.
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20.
Suspension cultures of isolated rat hepatocytes were used to investigate whether 7-ketocholesterol and cholestane-3,5,6-triol exert oxidative stress in cells as manifested by increased lipid peroxidation and the induction of the antioxidant enzymes catalase, glutathione peroxidase and superoxide dismutase. The oxysterols were found to increase the levels of both superoxide dismutase and catalase and to have variable effects on glutathione peroxidase activity. Increased lipid peroxidation was not observed, indicating that the endogenous antioxidant defense system was capable of protecting against any oxidative stress that might otherwise by exerted by 7-ketocholesterol or cholestane-3,5,6-triol. Covi-ox, a natural tocopherol blend reduced the effects of both oxysterols on the antioxidant enzymes. A concurrent reduction in the production of thiobarbituric acid-reactive substances in Covi-ox-treated cells is indirect evidence that reactive oxygen species were produced by oxysterols in hepatocyte suspension cultures.  相似文献   

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