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1.
Summary Candida pelliculosa var. acetaetherius is a strain of yeast which can utilize cellobiose as the carbon source. From a gene library prepared from this yeast, the -glucosidase gene has been cloned in a S. cerevisiae host using a chromogenic substrate, 5-bromo-4-chloro-3-indolyl--glucoside as an indicator. It was proved by Southern analysis that the DNA fragment carrying the -glucosidase gene originated from C. pelliculosa. -Glucosidase produced by S. cerevisiae transformants was secreted into the periplasmic space. In Candida, -glucosidase was not induced by cellobiose but was derepressed by lowering the concentration of glucose. The regulation of -glucosidase synthesis in S. cerevisiae carrying the cloned -glucosidase was not clear compared with that in Candida, however, the enzyme activity in low glucose medium (0.05%) was reproducibly higher than in high glucose medium (2%). We have found the sequence that controls the expression of the -glucosidase gene negatively in S. cerevisiae.  相似文献   

2.
In the present study of 9,000 individuals representative of the general population, we have considered whether the addition of common single nucleotide polymorphisms (SNPs) in the promoter region of Apolipoprotein E (APOE) improve the statistical explanation of variation in lipid traits and test the hypothesis that the estimated genotype effects are independent of factors indexed by gender and age. To address these questions, we have asked, for each gender and for each 20-year age strata (young: 20–39 years; middle-aged: 40–59 years; old: 60–79 years; very old: 80–100 years), how much trait variation is associated with the traditional 2, 3, and 4 allelic variations defined by the g.2059TC and g.2197CT SNPs in the fourth exon of the APOE gene, and how much additional trait variation is associated with genotypes defined by combining the g.2059TC and g.2197CT SNPs with one, two, or three promoter SNPs. Our study demonstrates that the pleiotropic effects of genotype variation defined by the traditional 2, 3, and 4 alleles on five plasma measures of lipid metabolism manifest differently in women and men and change significantly during the life cycle for high-density lipoprotein cholesterol in women. Multi-site genotypes defined by adding SNPs located in the 5 promoter region to the traditional g.2059TC and g.2197CT SNPs doubled the estimate of genetic variance of high-density lipoprotein and apolipoprotein Al in middle-aged females.  相似文献   

3.
Summary On the basis of the histochemical activity of succinic dehydrogenase, only two fibre-types are distinguished in pigeon pectoralis major muscle. These are narrow Red and broad White. The histochemical activity of myofibrillar ATPase was studied in these two distinct fibre-types. Both fibre-types showed high activity for the ATPase. Red fibres of pigeon pectoralis were not alkali-labile, at incubation pH 9.4, as were the Type I fibres of both avian and mammalian muscles. Again unlike Type I fibres, the Red fibres of pigeon pectoralis lacked the characteristic activation of acid-preincubated ATPase reaction. Pigeon pectoralis Red fibres are known to posses some characteristics of fast-twitch fibres (e.g. high fat, considerable phosphorylase, fibrillenstruktur myofibrillar arrangement, focal en plaque pattern of nerve endings). It is emphasized, therefore, that the pigeon pectoralis Red fibres are not equivalent to Type I or slow-twitch, muscle fibres, but they are possibly fast-twitch fatigue resistent or Type II Red muscle fibres.  相似文献   

4.
This study provides a critical historical review and analysis of the variety of human expressions which have been erroneously labeled under the grandiose category mass hysteria. It is argued that Western science reductionist approaches to the classification of mass hysteria treat it as an entity to be discovered transculturally, and in their self-fulfilling search for universals systematically exclude what does not fit within the autonomous parameters of its Western-biased culture model, exemplifying what Kleinman (1977) terms a category fallacy. As a result of objectivist methodologies, the etiology of actions labeled as mass hysteria is typically viewed as deviant, irrational or abnormal behavior resulting from a malfunctioning proper social order. However, what constitutes the correct social order is a function of a researcher's historical sociocultural and/or scientific milieu. This study reviews the problem, advocating Geertz's (1973) culturally relativistic approach to understanding various cross-cultural behavior that is sensitive to and tolerant of the unique context and milieu of participants. Mass or epidemic hysteria is viewed as an invention of Western psychiatry and should be abandoned and replaced with the term collective exaggerated emotions. Instead of attempting to discover a neatly packaged, unitary external disease entity, the focus of a meaning-oriented approach emphasizes the deciphering of foreign realities, semantic networks and symbol systems.  相似文献   

5.
Cultures of Trichodesmium from the Northern and Southern Great Barrier Reef Lagoon (GBRL) have been established in enriched seawater and artificial seawater media. Some cultures have been maintained with active growth for over 6years. Actively growing cultures in an artificial seawater medium containing organic phosphorus (glycerophosphate) as the principal source of phosphorus have also been established. Key factors that contributed to the successful establishment of cultures were firstly, the seed samples were collected from depth, secondly, samples were thoroughly washed and thirdly, incubations were conducted under relatively low light intensities (PAR 40–50molquantam–2s–1). N2 fixation rates of the cultured Trichodesmium were found to be similar to those measured in the GBRL. Specific growth rates of the cultures during the exponential growth phase in all enriched media were in the range 0.2–0.3day–1 and growth during this phase was characterised by individual trichomes (filaments) or small aggregations of two to three trichomes. Characteristic bundle formation tended to occur following the exponential growth phase, which suggests that the bundle formation was induced by a lack of a necessary nutrient e.g. Fe. Results from some exploratory studies showed that filament-dominated cultures of Trichodesmium grew over a range of relatively low irradiances (PAR 5–120molquantam–2s–1) with the maximum growth occurring at 40–50molquantam–2s–1. These results suggest that filaments of the tested strain are well adapted for growth at depth in marine waters. Other studies showed that growth yields were dependent on salinity, with maximum growth occurring between 30 and 37psu. Also the cell yields decreased by an order of magnitude with the reduction of Fe additions from 450 to 45nM. No active growth was observed with the 4.5nM Fe addition.  相似文献   

6.
Laboratory studies on predation, reproduction and development were conducted on three phytoseiid species,Typhlodromus pomi (Parrott),Phytoseius macropilis (Banks) andAmblyseius finlandicus (Oudemans). These species were dominant phytoseiid mites on the abandoned apple trees with which ecological experiments were carried out in southern Ontario, Canada. Throught the studies, a rust mite species (Diptacus gigantorhynchus sp. complex), a single consistent prey in the orchard, was used as food. Results showed that the three predators developed well with the rust mites as food, and thatA. finlandicus developed most rapidly and had the highest predation rate. However, this species showed a poor tolerance to low prey densities. These observations suggest that this species is a predacious species and the other two species were more or less general feeders. All species showed the same pre-mating behaviour (Amblyseius-Typhlodromus type), but they exhibited a variety of mating and oviposition behaviours.  相似文献   

7.
C. Lee  X. Li  E. W. Jabs  D. Court  C. C. Lin 《Chromosoma》1995,104(2):103-112
The cosmid clone, CX16-2D12, was previously localized to the centromeric region of the human X chromosome and shown to lack human X-specific satellite DNA. A 1.2 kb EcoRI fragment was subcloned from the CX16-2D12 cosmid and was named 2D12/E2. DNA sequencing revealed that this 1,205 bp fragment consisted of approximately five tandemly repeated DNA monomers of 220 bp. DNA sequence homology between the monomers of 2D12/E2 ranged from 72.8% to 78.6%. Interestingly, DNA sequence analysis of the 2D12/E2 clone displayed a change in monomer unit orientation between nucleotide positions 585–586 from a tail-to-head arrangement to a head-to-tail configuration. This may reflect the existence of at least one inversion within this repetitive DNA array in the centromeric region of the human X chromosome. The DNA consensus sequence derived from a compilation of these 220 bp monomers had approximately 62% DNA sequence similarity to the previously determined 8 satellite DNA consensus sequence. Comparison of the 2D12/E2 and 8 consensus sequences revealed a 20 bp DNA sequence that was well conserved in both DNA consensus sequences. Slot-blot analysis revealed that this repetitive DNA sequence comprises approximately 0.015% of the human genome, similar to that found with 8 satellite DNA. These observations suggest that this satellite DNA clone is derived from a subfamily of satellite DNA and is thus designated X satellite DNA. When genomic DNA from six unrelated males and two unrelated females was cut with SstI or HpaI and separated by pulsed-field gel electrophoresis, no restriction fragment length polymorphisms were observed for either X (2D12/E2) or 8 (50E4) probes. Fluorescence in situ hybridization localized the 2D12/E2 clone to the lateral sides of the primary constriction specifically on the human X chromosome.  相似文献   

8.
The most commonly quoted mechanism of the coupling between the electrochemical proton gradient and the formation of ATP from ADP and Pi assumes that all states of the F1 portion of the ATP synthase have subunits in tight, loose, and open conformations. Models based on this assumption are inconsistent with some of the available experimental evidence. A mechanism that includes an additional subunit conformation, closed, observed in the rat liver structure overcomes these difficulties.  相似文献   

9.
Different ζ globin gene deletions among Black Americans   总被引:7,自引:0,他引:7  
Summary Four types of chromosomes with a deletion between the human embryonic and globin genes were identified among 2.8% of 321 Black Americans from Georgia. Two deletions of approximately 11 kb which differed by about 300 bp occurred on chromosomes with or without a polymorphic Xba I site 5 to the globin gene [(X+) or (X-)]. The deletions are identifiable in Xba I digests of genomic DNA using an or a globin gene probe which yield fragments of 23 kb from (X+)–* chromosomes or 27 kb from (X)–* chromosomes. Digestion with other enzymes and probing with both and probes gave fragments typical of the two globin gene deletions previously identified in Polynesians. Among Black Americans, these globin gene deletions have been found in combination with globin gene deletions in trans but not in cis. Homozygotes have not been found. Hematologic data on carriers of the globin gene deletions in association with Hb AS, SS, and SC suggest that these deletions have no effect on the function of the adult globin genes.  相似文献   

10.
Summary The principal pancreatic islets of the teleost Scorpaena scropha are found ultrastructurally to contain four different kinds of parenchymal cells, viz. 1-(= D), 2-, -and agranular cells. The -cells show considerable variations in the shape of the secretory granules. A peculiar feature is that many of these granules are composed of fibrillar subunits, often in parallel arrangement. All -granules are surrounded by membranes and between the membrane and the granule core there is a moderately wide electron lucent space. The electron density of the cytoplasm in the -cells varies somewhat. The 2-cells possess typical secretory granules with an electron dense core and a closely applied membrane. The secretory granules in the 1-cells show also a closely applied membrane but a less dense core. Also in the -cells the electron opacity of the cytoplasm varies. The agranular cells are mainly characterized by low cytoplasmic electron density, narrow cisterns of endoplasmic reticulum and sometimes a laminated Golgi complex. Small immature secretory granules are occasionally seen in the cytoplasm of these cells. The significance of the fibrillar -granules remains obscure.This work was supported by grants from the Nordic Insulin Fund, the Town of Umeå, the Swedish Medical Research Council (Project No. B69-12X-718-04A), and by a postdoctoral fellowship from the United States Public Health Service.  相似文献   

11.
Of 147 microorganisms isolated from a loamy sand, 71 showed good growth with lindane (-1,2,3,4,5,6-hexachlorocyclohexane) and produced chloride in an aqueous medium. Thirteen soil microorganisms were selected to study the utilization of lindane. Lindane was metabolized by the microbes to -2,3,4,5,6-pentachloro-1-cyclohexene (-PCCH), -3,4,5,6-tetrachloro-1-cyclohexene (-TCCH), -3,4,5,6-tetrachloro-1-cyclohexene (-TCCH), -3,4,5,6-tetrachloro-1-cyclohexene (-TCCH), and pentachlorobenzene (PCB). Cells of Pseudomonas sp. No. 62 grown on lindane simultaneously adapted to -PCCH, -TCCH, -TCCH, -TCCH, PCB, 1,2,3,4-tetrachlorobenzene (1,2,3,4-TCB) and 1,2,4,5-tetrachlorobenzene (1,2,4,5-TCB). The bacteria degraded each of these chemicals at least partially as indicated by an increased rate of oxygen consumption.Abbreviations Lindane -1,2,3,4,5,6-hexachlorocyclohexane - -PCCH -2,3,4,5,6-pentachloro-1-cyclohexene - -TCCH -3,4,5,6-tetrachloro-1-cyclohexene - -TCCH -3,4,5,6-tetrachloro-1-cyclohexene - -TCCH -3,4,5,6-tetrachloro-1-cyclohexene - PCB pentachlorobenzene - 1,2,3,4-TCB 1,2,3,4-tetrachlorobenzene - 1,2,3,5-TCB 1,2,3,5-tetrachlorobenzene - 1,2,4,5-TCB 1,2,4,5-tetrachlorobenzene - 1,2,3-tCB 1,2,3-trichlorobenzene - 1,2,4-tCB 1,2,4-trichlorobenzene - 1,3,5-tCB 1,3,5-trichlorobenzene - 1,2-DCB 1,2-dichlorobenzene - 1,3-DCB 1,3-dichlorobenzene - 1,4-DCB 1,4-dichlorobenzene - MCB monochlorobenzene Contribution No. 631, Research Institute, Agriculture Canada, University Sub Post Office, London, Ontario N6A 5B7  相似文献   

12.
Our recent studies have revealed the existence of two distinct Gal: 3-O-sulfotransferases capable of acting on the C-3 position of galactose in a Core 2 branched structure, e.g., Gal14GlcNAc16(Gal13)GalNac1OBenzyl as acceptor to give 3-O-sulfoGal14GlcNAc13(Gal13)GalNAc1OB 20 and Gal14GlcNAc16(3-O-sulfoGal13)GalNAc1OB 23. We herein report the synthesis of these two compounds and also that of other modified analogs that are highly specific acceptors for the two sulfotransferases. Appropriately protected 1-thio-glycosides 7, 8, and 10 were employed as glycosyl donors for the synthesis of our target compounds.  相似文献   

13.
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   

14.
Summary In untreated adult male albino rats nuclear volume and the percentage of binucleate cells were determined in the first layer of hepatocytes adjacent to hepatic venous branches of varying diameters (<40 m, 40 m–80 m, 80 m–120m, 120 m–160 m, >160 m), and in the third and fourth layer of hepatocytes in the remainder of the perivenous parenchyma. In the first layer of hepatocytes adjacent to the vascular structures means of nuclear volume are significantly lower and percentage of binucleate cells significantly higher than in the cells of the remainder of the perivenous parenchyma. Within each area measured distribution curves of nuclear volume classes were homogeneous but showed heterogeneity in comparison with each other. The morphometric data presented in this study strongly support the opinion of the heterogeneity of liver cells in the perivenous zone, as previously postulated on the basis of histochemical investigations.Supported by the Deutsche Forschungsgemeinschaft (Hi 318/2-1)  相似文献   

15.
The stable isotope ratios of nitrogen were measured in the mysid,Neomysis intermedia, together with various biogenic materials in a eutrophic lake, Lake Kasumigaura, in Japan throughout a year of 1984/85. The mysid, particulate organic matter (POM, mostly phytoplankton), and zooplankton showed a clear seasonal change in 15N with high values in spring and fall, but the surface bottom mud did not. A year to year variation as well as seasonal change in 15N was found in the mysid. The annual averages of 15N of each material collected in 1984/85 are as follows: surface bottom mud, 6.3 (range: 5.7–6.9); POM, 7.9 (5.8–11.8); large sized mysid, 11.6 (7.7–14.3); zooplankton, 12.5 (10.0–16.4); prawn, 13.2 (9.9–15.4); goby, 15.1 (13.8–16.7). The degree of15N enrichment by the mysid was determined as 3.2 by the laboratory rearing experiments. The apparent parallel relationship between the POM and the mysid in the temporal patterns of 15N with about 3 difference suggests the POM (mostly phytoplankton) as a possible food source ofN. intermedia in this lake through the year.  相似文献   

16.
Zusammenfassung Achtzehn chemisch verschiedene synthetische Zellstreckungswuchs- und Hemmstoffe wurden an Epidermisschnitten von acht verschiedenen dicotylen und monocotylen Pflanzen hinsichtlich ihrer toxischen Wirkung auf das Plasma untersucht und die jeweils letal wirkende Konzentration bestimmt.Unter den getesteten typischen Zellstreckungswuchsstoffen konnte keine Substanz gefunden werden, die auf das Protoplasma der Testpflanzen stark toxisch wirkte. Bei den Zellstreckungshemmstoffen konnten zwei Gruppen unterschieden werden: Die eine Gruppe von Hemmstoffen war überaus stark toxisch wirksam, die andere dagegen nahezu ungiftig. Nachdem die Substanzen beider Gruppen im Zellstreckungstest aber starke Zellstreckungshemmung geben, wird angenommen, daß die ungiftigen Substanzen eine spezifische Wirkung auf das Zellstreckungssystem ausüben, während die giftigen Stoffe zumindest sekundär auf Grund einer allgemeinen Plasmaschädigung die Zellstreckung hemmen. Die getesteten Substanzen wurden ferner mit ihrer formativen Wirksamkeit auf Pflanzen verglichen und festgestellt, daß im allgemeinen nur in der Gruppe der ungiftigen Stoffe morphologisch aktive Substanzen zu finden sind.  相似文献   

17.
Summary Investigations into the relationship between sucrose hydrolysis, sorbitol formation and mineral ion concentration during bioethanol formation by Zymomonas mobilis 2716 revealed two distinct phenomena responsible for carbon flow diversion, a sucrose effect and a salt effect. Neither of the two phenomena affects sucrose hydrolysis, but they divert carbon flow of the fructose monomer leading to its own accumulation, sorbitol or oligosaccharide formation. Sucrose concentrations in excess of 15% (w/v) led to sorbitol formation, the level of which may exceed 2% (w/v) depending upon glucose accumulation during sucrose hydrolysis. Increasing mineral ion concentrations led initially to carbon losses and finally to fructose accumulation instead of sorbitol formation. This carbon loss can be corrected by the addition of invertase, which in turn leads to an increase in sorbitol, fructose and ethanol. Potassium and chloride are the dominant ions responsible for suppression of sorbitol formation and fructose uptake, encouraging oligosaccharide formation. These fructooligosaccharides must be of a type which can be converted to fructose, sorbitol and ethanol through the action of invertase. The requirement of invertase addition to prevent fructooligosaccharide formation is indirect evidence that Z. mobilis 2716 does not produce invertase.Offprint requests to: H. W. Doelle  相似文献   

18.
Part of a -amylase genomic DNA sequence from the oomycete, Achlya bisexualis was cloned by polymerase chain reaction (PCR) using degenerate oligonucleotide primers derived from the conserved regions of other known -amylase sequences. The 5- and 3-regions of the -amylase gene were amplified by genome walking method. The Ach. bisexualis -amylase gene consisted of a 1338bp open reading frame, encoding a protein of 446 amino acids with a molecular weight of 49 381Da, and was not interrupted by any intron. The deduced amino acid sequence of the -amylase gene had 67% similarity to the -amylase of Saprolegnia ferax, followed by 40% similarity to that ofArabidopsis thaliana. The -amylase gene was expressed in Saccharomyces cerevisiae placing it under the control of the alcohol dehydrogenase gene (ADC1) promoter.  相似文献   

19.
Zusammenfassung Kegel und Säulen der Schwanen-Eischale hinterlassen am Querschliff nach Entkalkung mit EDTA organisches (mucoproteides) Material als ein zusammenhängendes Gerüst, das sich mit Thionin metachromatisch färbt; ohne Demineralisierung oder wenigstens Anätzung bleibt Thionin an Schliffen und Bruchkanten der Schale wirkungslos. Das Lichtmikroskop zeigt an Schliffen nichts von dem organischen Material, es wurde während des Kristallwachstums fein zerteilt in Gitterlücken des Schalencalcits eingeschlossen. Es findet sich am stärksten angehäuft an den äueren und inneren Oberflächen der Kristall-individuen. In den Kegeln ist das Gerüst radial ausgebildet als die Loculi der Keile, und konzentrisch geschichtet, entsprechend den Lagen der Globularinklusionen, um deren jede herum Verdichtung der organischen Substanz statthat. In den inneren Säulen folgt das organische Gerüst dem Rhombenmuster; die äueren Säulen sind arm an organischer Substanz, hier verbleibt nach der Entkalkung eine dünne laterale Oberflächenschicht.
Summary The cones and columns of the swans egg shell leave behind after decalcification with EDTA an organic (mucoproteid) material in form of a continuous frame work stainable metachromatically with thionine. Without demineralisation or at least etching, thionine proves ineffectual in ground sections or breaking edges of the shell. In ground sections the light microscope demonstrates nothing of the organic material: it was inclosed during the crystal growth in submicroscopical lattice gaps of the calcite individuals. The organic material is chiefly accumulated in the outer and inner surfaces of the crystals. In the cones the organic frame work is developed radially as the loculi of the wedges and concentrically layered corresponding with the globular inclusions, concentrated in the circumference of each. In the inner columns the organic material follows to the rhomb pattern. The outer columns after decalcification only leave behind a thin lateral organic sheath.
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20.
Paddy levees form networks of narrow linear habitats and play various roles in cultural landscapes. Traditional landscapes on the west side of Lake Biwa consist of paddy field terraces and both stone and soil levees that have been maintained by paddy field management using local resources. Paddy levees in this study site are principally classified into five different types. Our study points out how differences in paddy levee structure as well as in management practices influence the plant species. Seventeen paddy levee transects were split into four habitat types based on their species components by TWINSPAN. Spatial characteristics and physical structures of paddy levees depended on natural conditions and human activities. The species–area curves of each levee type showed a clear distinction: the soil, stone and abandoned curves were steep, while the concrete and consolidated ones were gentle. The vegetation on consolidated levees was utterly different from the vegetation on traditional levee types from the aspect of species richness and species components. Soil type levees contained various woody plant species and included more diverse and indigenous plant species than abandoned type levees.  相似文献   

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