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1.
An efficient and reliable micropropagation system for Persian clover (Trifolium resupinatum L.) was developed using different explants and media. Node, hypocotyl and cotyledonary node explants were cultured on Murashige and Skoog (MS) medium supplemented with combinations of either 6-benzyladenine (BA) and indole-3-butyric acid (IBA) or BA, Kinetin (KIN) and IBA. Direct multiple shoots developed within 6weeks in all explants in most media tested. The best shoot multiplication capacity was obtained from cotyledonary node explants on MS medium containing 7.1M BA and 1M IBA or 14.1M BA and 1M IBA. Elongated shoots were rooted on either MS medium alone or combination with different concentrations of indole-3-butyric acid (IBA), indole-3-acetic acid (IAA) and -naphthaleneacetic acid (NAA). High rooting was achieved in half strength MS medium containing 8M IBA.  相似文献   

2.
Summary In cell-free extracts of E. coli merodiploids carrying F-factor with ilv-thi chromosome fragment the activity of RNA polymerase is not increased, and there is no excess of free active core-enzyme or sigma-factor. Only immunochemical analysis reveals 25% excess of RNA polymerase material in some merodiploids as compared to a haploid. However, neither the amount of + relative to total protein nor : ratio does not differ in haploid and merodiploids.  相似文献   

3.
Feulgen and silver-stained karyotypes and meiosis of two triploid viviparous onion forms (Allium cepa var.viviparum), the Croatian Ljutika and the Indian Pran, were comparatively analyzed. The results of chromosome measurements show that Ljutika and Pran are karyologically not identical, although significant similarities were found in the morphology of their chromosomes. Five geographically distant clones of Ljutika showed good agreement in the number and gross morphology of the chromosomes and in the number and position of NORs and interphase nucleoli. Heterotrivalents were predominant in meiosis of Ljutika but a relatively high frequency of higher multivalents together with univalents and bivalents were also observed. The relationship between Ljutika and Pran and their possible origin are discussed.  相似文献   

4.
A combination of molecular and in silico approaches was employed to assemble a survey of Na, K-ATPase genes contained in the ancestrally tetraploid genome of the Atlantic salmon (Salmo salar). Molecular characterization of genomic clones coding for the subunit revealed two single genes (1a and 2) and two pairs of presumably homeologous genes (1b/i-ii and 1c/i-ii). Each of the six genes showed high sequence similarity to isoforms previously isolated from rainbow trout and extensive structural differences relative to putative orthologs in the human genome. In silico analysis of expressed sequence tag (EST) collections indicated that at least five (1a, 1b, 1c, 2, and 3) and four (1a, 1b, 2, and 3b) subunit isoforms are expressed in Atlantic salmon. Meiotic linkage analysis further showed that Na, K-ATPase genes are dispersed throughout the salmon genome, with the exception of two multigene clusters on linkage groups AS-22 and AS-28. Duplicate gene copies for the isoform 1b were assigned to linkage groups with multiple homeologous anchors (AS-22 and AS-23), while 2 duplicates suggested a new homeologous affinity between AS-05 and AS-28. In addition, the comparison of linkage arrangements with rainbow trout also showed that the genomic organization of Na, K-ATPase genes is consistent with the evolutionary conservation of syntenic chromosome regions between these species.Electronic Supplementary Material Supplementary material is available for this article at .  相似文献   

5.
Summary The dorsal tegument of the mature cercaria of Notocotylus attenuatus is a syncytial, cytoplasmic layer, containing two types of secretory granule which are identifiable ultrastructurally. The type 1 secretory bodies are electron lucid, whereas most type 2 granules have a banded appearance. The ventral tegument contains granules which are secreted from the type 3 cells; the type 3 granules are membrane bound, electron dense, and consist of both an amorphous and a finely striated zone. The type 4 cells mainly contain cigar-shaped granules consisting of an amorphous core surrounded by concentric striations. The granules exhibit structural variability in shape and content. The type 4 cells undergo a cellular migration to the tegument during encystment. The structure of the posterior-lateral glands and mode of secretion of the granules are described. Possible functions of microtubules are discussed for each cell type. Details of some secretory processes involved in the formation of the hemispherical cyst wall are described. The layers of the cyst wall may be related to the granular contents of the various parenchymal cells of the cercaria. The tegument of the metacercaria originates primarily from the cytoplasm of the type 1, type 2, type 3 and type 4 cells.  相似文献   

6.
A new neoglycopeptide was synthesized and tested for its capability to bind to lactose permease of Escherichia coli and to inhibit the transport of lactose. The free 5- carboxypentyl-1-thio--D-galactopyranoside or the protected 2,3,4,6-tetra-O-acetyl-5-carboxypentyl-1-thio--D- galactopyranoside was linked to the N-terminal -amino group of the resin bound heptapeptide H-Phe-Phe-Gly-Gly-Gly-Gly-Ala-OH by different activation methods. Upon cleavage from the resin, deacetylation and purification, a neoglycopeptide which showed a significant inhibition of lactose permease was obtained.  相似文献   

7.
In this study, the in vivo effects of insulin and chronic treatment with bis(maltolato)oxovanadium (IV) (BMOV) on protein kinase B (PKB) activity were examined in the liver and skeletal muscle from two animal models of diabetes, the STZdiabetic Wistar rat and the fatty Zucker rat. Animals were treated with BMOV in the drinking water (0.75–1 mg/ml) for 3 (or 8) weeks and sacrificed with or without insulin injection. Insulin (5 U/kg, i.v.) increased PKB activity more than 10fold and PKB activity more than 3fold in both animal models. Despite the development of insulin resistance, insulininduced activation of PKB was not impaired in the STZdiabetic rats up to 9 weeks of diabetes, excluding a role for PKB in the development of insulin resistance in type 1 diabetes. Insulin-induced PKB activity was markedly reduced in the skeletal muscle of fatty Zucker rats as compared to lean littermates (fatty: 7fold vs. lean: 14fold). In contrast, a significant increase in insulinstimulated PKBa activity was observed in the liver of fatty Zucker rats (fatty: 15.7fold vs. lean: 7.6fold). Chronic treatment with BMOV normalized plasma glucose levels in STZdiabetic rats and decreased plasma insulin levels in fatty Zucker rats but did not have any effect on basal or insulininduced PKB and PKB activities. In conclusion (i) in STZdiabetic rats PKB activity was normal up to 9 weeks of diabetes; (ii) in fatty Zucker rats insulininduced activation of PKB (but not PKB) was markedly altered in both tissues; (iii) changes in PKB activity were tissue specific; (iv) the glucoregulatory effects of BMOV were independent of PKB activity.  相似文献   

8.
Summary Fundamentally, theoretically, there is only one process underlying genetic and cultural evolution: natural selection. Organism fitness-enhancement (adaptive significance) is one of its practical mechanisms; group formation and maintenance is another, often but not always through fitness-enhancement; and need-fulfillment is still another. If Durham can accept that formulation, and switch from organism-thinking to instruction-thinking (Cloak, 1975: 178), he will free himself from two handicaps: First, he can forget his worries about reductionism and determinism (1976a: 100, 101). Under this general theory of natural selection, cultural evolutionis biological evolution, continued by other (nongenetic) means. Second, he will spare himself the appearance of anthropomorphism, mentalism, and wishy-washiness attendant on his discussion of kinds of significance, other than adaptive significance, of cultural behaviors (1976a: 102–106, 115).  相似文献   

9.
The general attributes of ecosystems are examined and a naturally occurring reference ecosystem is established, comparable with the isolated system of classical thermodynamics. Such an autonomous system with a stable, periodic input of energy is shown to assume certain structural characteristics that have an identifiable thermodynamic basis. Individual species tend to assume a state of least dissipation; this is most clearly evident in the dominant species (the species with the best integration of energy acquisition and conservation). It is concluded that ecosystem structure results from the antagonistic interaction of two nearly equal forces. These forces have their origin in the Principle of Most Action (least dissipation or least entropy production) and the universal Principle of Least Action. Most action is contingent on the equipartitioning of the energy available, through uniform interaction of similar individuals. The trend to Least action is contingent on increased dissipation attained through increasing diversity and increasing complexity. These principles exhibit a basic asymmetry. Given the operation of these opposing principles over evolutionary time, it is argued that ecosystems originated in the vicinity of thermodynamic equilibrium through the resonant amplification of reversible fluctuations. On account of the basic asymmetry the system was able to evolve away from thermodynamic equilibrium provided that it remained within the vicinity of ergodynamic equilibrium (equilibrium maintained by internal work, where the opposing forces are equal and opposite).At the highest level of generalization there appear to be three principles operating: i) maximum association of free-energy and materials; ii) energy conservation (deceleration of the energy flow) through symmetric interaction and increased homogeneity; and iii) the principle of least action which induces acceleration of the energy flow through asymmetrical interaction. The opposition and asymmetry of the two forces give rise to natural selection and evolution.  相似文献   

10.
Summary The total pigment and astaxanthin content ofPhaffia rhodozyma increased with increasing concentrations -pinene up to 500 l -pinene/l. Above this concentration the total pigment and astaxanthin content as well as the biomass production decreased. The addition of 500 l -pinene/l increased the total pigment content from 1652 g/g to 2201 g/g and the astaxanthin content from 1554 g/g to 1883 g/g. A sharp decrease in maximum specific growth rate occurred above 150 l -pinene/l.  相似文献   

11.
The developmental profiles of four glycosidase enzymes (-D-glucosidase, -D-glucuronidase, -D-N-acetylglucosaminidase and -D-galactosidase) in the cochleas, cochlear nuclei and inferior colliculi of four strains of mice were investigated. The strains used were an audiogenically seizure-susceptible strain (DBA/2) and three non-susceptible strains (BALB/c, C3H/He and Swiss/A2G). The enzymic activities fell to varying degrees from 7 to 28 days of age. Two significant observations were made—-D-glucuronidase was low in the regions of the C3H/He strain, and -D-galactosidase was particularly low in the regions of the DBA/2 strain. The very low activity of -D-galactosidase in the DBA/2 mice is discussed in relation to the ganglioside patterns known to be present in these seizure-susceptible mice. Studies on the DNA contents of these auditory regions in the four strains showed no correlation with seizure sensitivity.This paper is dedicated to Dr. Derek Richter on his seventy-fifth birthday.  相似文献   

12.
Summary -Glutamylamine cyclotransferase, an enzyme found in a number of animal tissues and cells, catalyzes the conversion of -(L--glutamyl)-L-lysine to free lysine and 5-oxo-L-proline as well as the release of free amines and the formation of 5-oxo-L-proline from a variety of other L--glutamylamines. Among its substrates are both the mono- and di--glutamyl derivatives of putrescine, spermidine and spermine, and a derivative of -(L--glutamyl)-L-lysine in which both the -amino group and the carboxyl group of the lysine moiety are blocked. The enzyme does not act on most -glutamyl--amino acids, nor is it active toward the -lysyl derivatives of L-aspartic acid or D-glutamic acid. Derivatives of -(L--glutamyl)-L-lysine in which the -amino or the -carboxyl function of the glutamyl moiety is blocked also do not serve as substrates. The specificity of -glutamylamine cyclotransferase is in accordance with the proposal that it functions biologically in the latter stages of the catabolism of products of the action of transglutaminases. Some suggestions as to the manner in which -glutamylamine cyclotransferase serves this function are made based on present knowledge of protein degradation.  相似文献   

13.
The properties of the -2-l-fucosyltransferases in submaxillary gland preparations from blood group ABH secrefors and non-secretors were compared. The level of activity in the non-secretor gland homogenates amounted to about 5% only of that found in the secretor gland preparations. The enzymes from the two sources differed in solubility properties, charge and affinities for donor and acceptor substrates. The enzyme from secretor glands showed a preference for acceptors with Type 1 [d-galactosyl(1–3)-N-acetyl-d-glucosamine] structures whereas the enzyme from non-secretor glands had a preference for Type 2 [d-galactosyl(1–4)-N-acetyl-d-glucosamine] structures.These results demonstrate that expression of the secretor gene (Se) is associated with a molecular form of the -2-l-fucosyltransferase that is different from the species present in the same tissue when theSe gene is not expressed.  相似文献   

14.
D[3H]mannoheptulose was recently reported to be poorly taken up by tumoral pancreatic islet cells of the RINm5F and INS1 lines. We have now investigated the effects of Dmannoheptulose upon Dglucose metabolism in these two cell lines. Dmannoheptulose (1.0–10.0 mM) only caused a minor decrease of Dglucose metabolism in RINm5F cells, whether at low (1.1 mM) or higher (8.3 mM) Dglucose concentration. A comparable situation was found in INS1 cells examined after more than 20 passages. In both cases, however, the hexaacetate ester of Dmannoheptulose (5.0 mM) efficiently inhibited Dglucose metabolism. In the INS1 cells, the relative extent of the inhibitory action of Dmannoheptulose upon Dglucose metabolism increased from 12.4 ± 2.6 to 38.3 ± 3.8% as the number of passages was decreased from more than 20 to 13–15 passages, the latter percentage remaining lower, however, than that recorded in INS1 cells also examined after 13–15 passages but exposed to Dmannoheptulose hexaacetate (66.9 ± 2.2%). These findings when compared to our recent measurements of D[3H]mannoheptulose uptake, reinforce the view that the entry of the heptose into cells and, hence, its inhibitory action on Dglucose metabolism are dictated by expression of the GLUT2 gene.  相似文献   

15.
Zusammenfassung Es gibt Männer, die mit dem Nagelschen Anomaloskop untersucht als protanop befunden und daraufhin für rotgrünblind erklärt werden, die aber im täglichen Leben nicht nur rote Kleidungsstücke unmittelbar als rot erkennen, sondern auch Verkehrslichter ohne weiteres als rot bzw. grün wahrnehmen. Die Träger dieser bisher verkannten Varietät des Farbensinns unterscheiden sich von voll farbentüchtigen Männern durch eine wesentlich höhere Schwelle ihres Rotgrünsinns; sie ist X-gekoppelt erblich.Die Dreifarbentheorie ist unhaltbar, weil sie mit dem Vorkommen echter Rotgrünblindheit, bei der als Grundfarben nur Gelb und Blau wahrgenommen werden, unvereinbar ist. Normal Farbentüchtige sollte man daher nicht wie bisher normale Trichromate nenne; denn sie können vier Grundfarben (Rot, Gelb, Grün, Blau) wahrnehmen; sie sind also Tetrachromate. Ein solcher Terminus erübrigt sich aber. Nachdem die Dreifarbentheorie und mit ihr die Trichromaten erledigt sind, genügt die Bezeichnung normal Farbentüchtige.
Experience with a formerly mistaken variety of color vision. Theoretical and practical consequences
Summary Some men are thought to be protanopes if studied with Nagel's anomaloscope, yet they are not only able to recognise in everyday life red clothing immediately as red, but also see traffic lights as red and green, respectively. Men affected with this formerly mistaken variety of colour vision differ from those with normal colour vision by their higher threshold of red-green perception. The variety is X-linked.The three-colour theory cannot be reconciled with the existence of genuine redgreenblindness, in which the only basic colours seen are yellow and blue. Persons with normal colour vision should not be called normal trichromates, as they perceive four basic colours red, yellow, green and blue. They are tetrachromatic. This term is unnecessary, however. As the three-colour theory and the expression trichromate are obsolete, it is sufficient to refer to normal colour vision.
  相似文献   

16.
Zusammenfassung Im sessilen Bulbus olfactorius von Teleosteern werden große Nervenzell-Somata als bulbäre Riesenzellen beschrieben. Sie treten bei Arten mit einem gestielten Bulbus nicht auf. Ihre Anordnung geht parallel mit dem bulbären Verlauf des Nervus terminalis. Holmgrens Kaudale Zellgruppe bzw. das Kerngebiet des Nervus terminalis (Scharrer) ist eine häufig anzutreffende Gruppierung dieser Zellen am caudalen Bulbusende. Es wird die Möglichkeit erörtert, ob die bulbären Riesenzellen nicht den Ganglienzellen des Nervus terminalis verwandte Strukturen darstellen.
Giant cells in the olfactory bulb of teleostean fishes
Summary Large nerve cell somata are described as bulbar giant cells in the sessile olfactory bulb of teleostean fishes. They are not found in species with a stalked olfactory bulb. They are arranged along the bulbar course of the nervus terminalis. In the Kaudale Zellgruppe of Holmgren and the Kerngebiet des Nervus terminals of Scharrer a greater part of these giant cells lie at the caudal end of the bulb. It is discussed if these cells are related to the ganglion cells of the nervus terminalis.
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17.
Summary Two double heterozygous 0/0 thalassemic sibs of Mexican descent were studied. The father had a 0/0 genotype, while the mother, one sib and several maternal relatives were 0/0 heterozygotes. Parental consanguinity and an apparently low frequency of thalassemia among Mexicans suggested a possible common origin of both 0 and 0 genes. A hypothesis to explain such a possibility is proposed on the basis of a partial mispairing between 0 and genes followed by a crossing-over which would results in a 0 recombinant gene. This hypothesis could also be extended to explain the 22 gluala, 22 alaglu and 116 arghis Hb variants as recombinants from double crossing-over between and mispaired genes for which the name interstitial-Lepore is proposed.  相似文献   

18.
Annual nitrogen and phosphorus budgets for the whole North Sea taking into account the most recent data available were established. The area considered has a total surface of approximately 700,000km2 and corresponds to the definition by OSPARCOM (Oslo and Paris Commission) with the exclusion of the Skagerrak and Kattegat areas. Input and output fluxes were determined at the marine, atmospheric, sediment and continental boundaries, and riverine inputs based on river flows and nutrient concentrations at the river–estuary interface were corrected for possible estuarine retention. The results showed that the North Sea is an extremely complex system subjected to large inter-annual variability of marine water circulation and freshwater land run-off. Consequently, resulting total N (TN) and P (TP) fluxes are extremely variable from 1 year to another and this has an important influence on the budget of these elements. Total inputs to the North Sea are 8870±4860kTNyear–1 and 494±279kTPyear–1. Denitrification is responsible for the loss of 23±7% of the TN inputs while sediment burial is responsible for the retention of only of 2±2% of the TP input. For TN, due to the large variability on marine and estuarine fluxes, and to the uncertainty related to the denitrification rate, it was concluded that the North Sea could either be a source (1930kTNyear–1) or a sink (1700kTNyear–1) for the waters of the North Atlantic Ocean. For TP it was concluded that the North Sea is mostly a source (–4 to 52kTPyear–1) for the waters of the North Atlantic Ocean.  相似文献   

19.
Mild cerebral anoxic/ischemic/stress insults promote tolerance and thereby protect the brain from subsequent lethal anoxic/ischemic insults. We examined whether specific activation of PKC , , , or isoforms is associated with ischemic preconditioning (IPC) in rat brain. IPC was produced by a 2-minute global cerebral ischemia. Membrane and cytosolic fractions of the hippocampi were immunoblotted using specific antibodies for PKC, , , and . PKC showed a significant translocation to the membrane fraction from 30 min to 4 h and PKC at 4 h following IPC. In contrast, the membrane/cytosol ratio of PKC showed a tendency to decrease at 30 min and 8 h, and the membrane/cytosol ratio of PKC was significantly decreased from 30 min to 24 h following IPC. These findings indicate PKC isoform-specific membrane translocations in the hippocampus after brief global brain ischemia and suggest that activation of PKC and PKC may be associated with IPC-induced tolerance in the rat hippocampus.  相似文献   

20.
T cells in murine lupus: propagation and regulation of disease   总被引:4,自引:0,他引:4  
MRL/Mp-lpr/lpr mice develop a spontaneous lupus syndrome, including hypergammaglobulinemia, autoantibodies, glomerulonephritis, and lymphadenopathy. To investigate the role of lymphocyte subsets in the pathogenesis of disease, lupus-prone MRL mice deficient in T cells, T cells, or both were generated. Mice deficient in T cells developed a partially penetrant lupus syndrome, characterized by lymphadenopathy, elevated levels of class-switched immunoglobulins, an increased incidence of antinuclear antibodies, and immune deposits in kidneys which progressed to renal insufficiency over time. In comparison to wild type animals, T cell-deficient animals developed an accelerated and exacerbated disease phenotype, characterized by accelerated hypergammaglobulinemia and enhanced autoantibody production and mortality. Repertoire analysis of these latter animals identified polyclonal expansion (V) of CD4+B220-cells. Mice lacking both and T cells failed to generate class-switched autoantibodies and immune complex renal disease. First, these findings demonstrate that murine lupus in the setting of Fas-deficiency does not absolutely require the presence of T cells, and they also suggest that a significant basis for MRL/lpr disease, including renal disease, involves T cell-independent, T cell dependent, polyreactive B cell autoimmunity, upon which T cell-dependent mechanisms aggravate specific autoimmune responses. Second, these data indicate that T cells partake in the regulation of systemic autoimmunity, presumably via their effects on CD4+B220-T cells that provide B cell help. Finally, these results demonstrate that MRL/lpr B cells, despite their intrinsic abnormalities, cannot per se cause tissue injury without T cell help.Abbreviations snRNPs small nuclear ribonucleoprotein particles  相似文献   

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