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1.
Summary Pinealectomy of house sparrows on 3L:21D (3 h light per 24 h) resulted in a significant increase in the time between the onset of perch-hopping activity and lights on (on) as well as the time between the offset of activity and lights of (off). The daily variance in on and off was also increased following the removal of the pineal gland. On longer light cycles (i.e., 5L:19D; 7L:17D), neither on or off, nor the variance of on or off was different between sham-pinealectomized and pinealectomized sparrows. Upon returning the birds to an ultrashort light cycle, 1L:23D, off, as well as the variance in on and off were again found to be significantly larger in the pinealectomized birds when compared to sham-operated controls. These results indicate that the effects of pinealectomy on the entrained rhythm of locomotor activity are most pronounced when birds are exposed to a weak entraining agent, such as an ultrashort light: dark cycle. In view of the observation that pinealectomy can alter the phase relationship between activity onset and offset, it is suggested that the pineal gland may be involved in the coupling of the oscillators that regulate activity onset and offset.  相似文献   

2.
The specificity of perch (Perca fluviatilis) roe fucolectin was studied using the protein dot blot technique, followed by detection with colloidal gold–labeled neoglycoproteins bearing human milk oligosaccharides. The strongest binding was noted with the H type 1 pentasaccharide lacto-N-fucopentaose (Fuc1-2Gal1-3GlcNAc1-3Gal1-4Glc); the interaction with the H type 6 trisaccharide 2"-fucosyllactose (Fuc1-2Gal1-4Glc) was weaker. Binding of the perch lectin to the Lewis antigens (associated with tumors and embryonic tissues) was also studied. It was found that the lectin weakly interacted with the hexasaccharide lacto-N-difucohexaose I, Leb (Fuc1-2Gal1-3[Fuc1-4]GlcNAc1-3Gal1-4Glc), but not with Lea, Lec, or Lex antigens. Thus, the perch roe lectin exhibited pronounced differences in carbohydrate specificity from other fucolectins—a feature that may be used in structural studies and isolation of fucose-containing glycoconjugates.  相似文献   

3.
The release of glutathione from astroglial cells was investigated using astroglia-rich primary cultures prepared from the brains of newborn rats. These cells release glutathione after onset of an incubation in a glucose-containing minimal medium. The amount of extracellular glutathione increased with the time of incubation, although the accumulation slowed down gradually. An elevated rate of increase of the glutathione concentration in the incubation medium was found if the astroglial ectoenzyme -glutamyl transpeptidase was inhibited by acivicin. The activity of -glutamyl transpeptidase in astroglia-rich primary cultures, which was found to be 1.9 ± 0.3 nmol/(min × mg protein), was markedly reduced if the cells had been incubated in the presence of acivicin. After 2 h of incubation with acivicin half-maximal and maximal inhibition of -glutamyl transpeptidase activity was found at concentrations of about 5 M and 50 M, respectively. In the presence of acivicin at a concentration above 10 M the glutathione content found released from astroglial cells apparently increased almost proportional to time for up to 10 h. Under these conditions the average rate of release was 2.1 ± 0.3 nmol/(h × mg protein) yielding after a 10 h incubation an extracellular glutathione content three times that of the medium of cells incubated without inhibitor. Half-maximal and maximal effects on the level of extracellular glutathione were found at 4 M and 50 M acivicin, respectively. After a 10 h incubation with acivicin the intracellular content of glutathione was reduced to 75% of the level of untreated astroglial cultures. These results suggest that glutathione released from astroglial cells can serve as substrate for the ectoenzyme -glutamyl transpeptidase of these cells.  相似文献   

4.
Functionally active Na2+,K2+-ATPase isozymes containing three types of the catalytic subunits (1, 2, and 3) were obtained from calf brain by two methods: selective removal of contaminating proteins according to Jorgensen (1974) and selective solubilization of the enzyme with subsequent reformation of the membrane structure according to Esmann (1988). All preparations were characterized with respect to ouabain-inhibition constants. The presence of the cytoskeleton protein tubulin (3 isoform) in the high-molecular-weight complex of Na2+,K2+-ATPase 31 isozyme from brain stem axolemma and the junction between Na2+,K2+-ATPase 3 subunit and tubulin 3 subunit are shown for the first time.  相似文献   

5.
The molecular basis of HbH disease in Taiwan   总被引:1,自引:0,他引:1  
Summary We have determined the molecular characteristics of -thalassemia in 12 HbH subjects from Taiwan by restriction endonuclease mapping with -and -specific probes. We have found four types of defects in the -thalassemia-2 genetic determinant: 3.7 type I; 4.2; CS; and T. All HbH subjects carried the ——SEA genotype in the -thalassemia-1 determinant. At least two different subtypes of ——SEA genotype were observed in this study.  相似文献   

6.
H. Rehder 《Oecologia》1982,55(1):120-129
Summary The total nitrogen and nitrate turnovers of three plots of plant communities typical of cattle resting sites in the Bavarian Alps were investigated. Annual net N mineralisation of the soil and N content of the above-ground phytomass at maximum development are low in the Senecio cordatus dominated community W at 1,450 m altitude (80 and 57 kg N/ha respectively) and highest in the nearly pure Rumex alpinus stand K (1,240 m) (156 and 148 kg N/ha). The subalpine mixed Rumex alpinus community S (1,790 m) is intermediate with low mineralisation but high N content in the aboveground parts (69 and 128 kg N/ha). In general the mineralisation values are below those from other comparable plant communities. The main component of N mineralisation is nitrification in all three plots.The nitrate content in the phytomass at full development increases from 0.1 g/m2 in W to 0.3 g/m2 in S and to 1.0 g/m2 in K. With one exception (Adenostyles alliariae) no species showed a real nitrate accumulation in the leaf laminae towards the end of the growing season.  相似文献   

7.
Acute and chronic arsenic exposure results in toxicity in humans and causes many neurological and other manifestations. For the first time the present study reports that zinc decreases arsenic-induced apoptosis and also confirms a single report of apoptosis induced by arsenic in a neuronal cell line. Apoptosis measured by DEVD-caspase activity peaked between 10 M and 20 M of arsenic trioxide. Higher concentrations of arsenic up to 40 M caused increasing cell death with diminishing DEVD-caspase activity. The beneficial effect of zinc was proportional to its concentration with a significant decrease in arsenic-induced DEVD-caspase activity at 50 M and 75 M zinc (P<0.05). This finding may be of therapeutic benefit in people suffering from chronic exposure to arsenic from natural sources, a global problem especially relevant to millions of people on the Indian subcontinent.  相似文献   

8.
Summary Genetic evidence for a dimeric structure of dihydropteridine reductase in man and in the fish species Cheirodon axelrodi and Salmo irideus is presented. A single locus in man and two loci in the fishes examined encode this enzyme. Zymograms revealed two alleles for the locus in man and two alleles for each locus in the fish Cheirodon axelrodi. The liver homogenate of a patient with dihydropteridine reductase deficiency showed no detectable activity in the gel, while his parents showed the normal electrophoretic phenotype.  相似文献   

9.
Yellow pitaya (Mediocactus coccineus) seeds were sown on Murashige and Skoog (1962) mineral salt medium. After germination, epicotyls were placed on media enriched with a combination of naphthaleneacetic acid (NAA) (0.05, 0.27 or 0.54 M) and benzyladenine (BA) (2.2 or 4.4 M). The apical tip was excised from half of the shoots and the other half were kept intact. Different values for proliferation rate, shoot length and thickness were observed on each medium. The cotyledons and roots were placed on MS medium supplemented with NAA (2.7 or 5.4 M) and embryogenic calluses were formed. Somatic embryos were induced on these media and then they normally developed on a growth regulator-free medium.Abbreviations BA benzyladenine - MS Murashige and Skoog - NAA -naphthalenacetic acid  相似文献   

10.
Summary The extent of filter paper degradation by extracellular preparations fromT. reesei and its mutants with a decreasing level of -glucosidase and an increasing level of endoglucanase has been determined. The ability to degrade cellulose is restricted by the level of endoglucanase and not by -glucosidase.  相似文献   

11.
To test the hypothesis that the T-cell receptor (Tcr) gene encodes a natural killer (NK) cell receptor molecule, three human NK clones and fresh peripheral blood lymphocytes with NK activity from two patients with a CD16+ lymphocytosis were analyzed for rearrangements and expression of the human Tcr , , and genes. Two of the clones displayed distinct rearrangements of their Tcr and genes and expressed mature Tcr , , and l RNA. However, one of the clones and both patient samples displayed marked NK activity but failed to rearrange or express any of their Tcr genes. These findings demonstrate that human natural killer activity is not dependent on Tcr gene rearrangement and expression. In addition, they confirm previous findings concerning the lack of Tcr and gene expression in some natural killer cells. Thus, they suggest the existence of additional NK-specific recognition molecules.  相似文献   

12.
Residual toxicities of registered and selected experimental pesticides used on citrus against Agistemus industani Gonzalez (Acari: Stigmaeidae) were compared. Pesticides considered highly toxic to A. industani were: abamectin 0.15 EC at 731ml/ha+FC 435-66 petroleum oil at 46.8l/ha, pyridaben 75WP at 469g/ha, ethion 4EC at 7.01l/ha+FC 435-66 petroleum oil at 46.8l/ha, propargite 6.55 EC at 3.51l/ha, chlorfenapyr 2SC at 1.46l/ha applied alone or in combination with FC 435-66 petroleum oil at 46.8l/ha, sulphur 80DF at 16.81kg/ha, dicofol 4EC at 7.01l/ha, fenbutatin oxide 50WP at 2.24kg/ha, benomyl 50WP at 2.24kg/ha, benomyl 50WP at 1.68kg/ha+ferbam 76 GF at 5.60kg/ha, ferbam 76GF at 11.21kg/ha, neem oil 90EC at 46.8l/ha, and copper hydroxide DF (40% metallic copper) at 4.48kg metallic copper/ha+FC 435-66 petroleum oil at 46.8l/ha. Pesticides that were moderately to slightly toxic included: copper sulphate 98% at 4.48kg metallic copper/ha+FC 435-66 petroleum oil at 46.8l/ha, fenbuconazole 2F at 280ml/ha+FC 435-66 petroleum oil at 46.8l/ha, FC 435-66 petroleum oil applied alone at 46.8l/ha or 23.4l/ha, and diflubenzuron 25WP at 1.40kg/ha. Pesticides that were non-toxic included: fenbuconazole 2F at 585ml/ha, malathion 57EC at 5.85l/ha, FC 435-66 petroleum oil at 46.8l/ha, carbaryl 80S at 3.36kg/ha, chlorpyrifos 4EC at 4.68l/ha, and formetanate 92SP at 1.12kg/ha. Understanding the toxic effects of field weathered pesticides against key predacious mite species is important for effective IPM. The results of this study provide a comparison of direct and indirect toxic effects of various pesticides to A. industani under field conditions.  相似文献   

13.
Summary The temporal muscles of the guinea pig show a sexual differentiation reflected in their histochemical enzyme pattern. Using histochemical methods for mitochondrial (SDH, -GPDH), and glycolytic enzymes (phosphorylase, LDH) it could be shown, that in adult animals the male muscle is a white muscle with marked activity of glycolytic enzymes, the female muscle a red muscle displaying high activity of mitochondrial enzymes. This differential enzyme pattern can be converted by the application of testosterone to the female type during the postnatal development. The male sex hormone thus affects the histochemical enzyme pattern of the muscle, converting the red, female into a white, male muscle in the female guinea pig.  相似文献   

14.
The carbohydrate-binding specificity ofPseudomonas aeruginosa lectin I (PA-I) in iodinated or biotinylated form was studied. A large number of glycosphingolipids, as well as some glycoproteins and neoglycoproteins were used as ligands. Also, inhibition by free saccharides of PA-I binding to glycosphingolipids was tested. It was found that the lectin binds most strongly to terminal and nonsubstituted Gal3Gal- or Gal4Gal-structures.Abbreviations PA-I Pseudomonas aeruginosa lectin I - Cer ceramide - lactosylceramide Gal4GlcCer - iso globotriaosylcerami Gal3Gal4GlcCer - globotriaosylceramide Gal4Gal4GlcCer - globoside or globotetraosylceramide GalNAc3Gal4Gal4GlcCer - Forssman glycolipid GalNAc3GalNAc3Gal4Gal4GlcCer - P1 glycolipid Gal4Gal4GlcNAc3Gal4GlcCer - lactoneotetraosylceramide Gal4GlcNAc3Gal4GlcCer - B5 glycolipid Gal3Gal4GlcNAc3Gal4GlcCer - gangliotetraosylceramide Gal3GalNAc4Gal4GlcCer - GM1 Gal3GalNAc4(NeuAc3)Gal4GlcCer - RBC red blood cells - BSA bovine serum albumin - PBS phosphate-buffered saline - SDS sodium dodecyl sulfate - TLC thin-layer chromatography - HPLC high pressure liquid chromatography - MS mass spectrometry - FAB fast-atom bombardment - EI electron impact  相似文献   

15.
Zusammenfassung In den Muskelzellen von falschen Sehnenfäden des linken Ventrikels der Ratte kommen quergestreifte Spiralfibrillen von meist submikroskopischer Größe vor. Sie sind mit einem Ende an der seitlichen Zellmembran oder an Einstülpungen der Zellmembran befestigt. Sie verlaufen von den Anheftungsstellen aus in gegenläufigen Spiraltouren und strahlen in die zentral gelegenen Längsfibrillen ein. Ihr Filamentaufbau und ihre enge Beziehung zu den Terminalzysternen des sarkoplasmatischen Retikulums sind die gleichen wie bei den Längsfibrillen. Es wird angenommen, daß die beobachteten Spiralfibrillen Vorläufer der lichtmikroskopisch sichtbaren Ringbinden (Spiralbinden) sind, die einen funktionell notwendigen Bestandteil der Weichteilmuskulatur (=nicht Skeletstücke miteinander verbindende Muskulatur) darstellen. Spiralfibrillen und Ringbinden sind selbst nicht als pathologisch anzusehen. Beim Auftreten an atypischer Stelle können sie aber eine durch einen pathologischen Prozeß verursachte Veränderung des Muskelgefüges anzeigen.
Submicroscopic ringbinding - a functional structure of Weichteilmuskulatur
Summary Spirally arranged myofibrils are described in perfusion fixed muscle strings which run freely through the left ventricle of the rat heart. They are very small and lie mainly between the sarcolemma and longitudinally arranged myofibrils. They are attached with one end to the lateral cell border or to invaginations of the cell membrane. From the attachment sites they run spirally in opposite directions and join the longitudinal myofibrils. Their filament pattern and their relationship to terminal cysternae of the sarcoplasmic reticulum is the same as in longitudinal myofibrils. It is concluded that these spirally wound myofibrils are precursors of ringbinding and that ringbinding is of functional significance in muscles not attached on both sides to bone (Weichteilmuskulatur). Ringbinding in itself is not considered to be pathologic. However, ringbinding in an unusual place may indicate a change in muscle architecture caused by pathologic processes.


Die Untersuchung wurde mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft durchgeführt.

Herrn Prof. Dr. med. Dr. phil. A. Kiesselbach zum 60. Geburtstag gewidmet.

Weichteilmuskulatur means muscles not connecting skeletal elements.  相似文献   

16.
Incubation of synthetic Man\1-4GlcNAc-OMe, GalNAc1-4GlcNAc-OMe, Glc1-4GlcNAc-OMe, and GlcNAc1-4GlcNac-OMe with CMP-Neu5Ac and rat liver Gal1-4GlcNAc (2-6)-sialyltransferase resulted in the formation of Neu5Ac2-6Man1-4GlcNAc-OMe, Neu5Ac2-6GalNAc1-4GlcNAc-OMe, Neu5Ac2-6Glc1-4GlcNAc-OMe and Neu5Ac2-6GlcNAc1-4GlcNAc-OMe, respectively. Under conditions which led to quantitative conversion of Gal1-4GlcNAc-OEt into Neu5Ac2-6Gal1-4GlcNAc-OEt, the aforementioned products were obtained in yields of 4%, 48%, 16% and 8%, respectively. HPLC on Partisil 10 SAX was used to isolate the various sialyltrisaccharides, and identification was carried out using 1- and 2-dimensional 500-MHz1H-NMR spectroscopy.Abbreviations 2D 2-dimensional - CMP cytidine 5-monophosphate - CMP-Neu5Ac cytidine 5-monophospho--N-acetylneuraminic acid - COSY correlation spectroscopy - DQF double quantum filtered - HOHAHA homonuclear Hartmann-Hahn - MLEV composite pulse devised by M. Levitt - Neu5Ac N-acetylneuraminic acid - Neu5Ac2en 2-deoxy-2,3-didehydro-N-acetylneuraminic acid  相似文献   

17.
Basic concepts in quantitative biology of metabolism   总被引:1,自引:0,他引:1  
Summary 1. The theories of open systems, feedback, allometry and growth according toBertalanffy are reviewed with respect to their experimental applications.2. The models of both open system and feedback apply to a wide range of phenomena in physiology, and represent essential expansions of physical theory. The two conceptions should be clearly distinguished; the feedback model (homeostasis) should not be considered a cover-all for physiological regulation in general or identified with systems theory.3. The allometric equation represents the simplest possible relation between body size and metabolic processes. It is of a wide applicability and expresses the harmonization of processes in living systems. However, there is no surface- or 3/4-power law or law of progressive reduction of metabolic rates. The allometric relationship greatly varies in physiological phenomena.4. Variations of the relation between body size and metabolic rate may occur (a) in different tissues or in different species; (b) due to changes of physiological conditions; (c) due to different experimental designs. Among the conditions altering this relation are such factors as physiological activities, sex, season, previous acclimation, etc.5. The size-dependence of total metabolism in mammals is different under basal conditions, in a non-thermoneutral environment, and under conditions of muscular activity. The variations followLocker's rule, i. e., with an absolute increase of metabolic rate (expressed by the constantb of the allometric equation), regression with respect to body size (expressed by the slope of the allometric line,a) tends to decrease.6. The growth equations afterBertalanffy represent a highly simplified model which, however, covers many phenomena and regularities found in the physiology of metabolism and growth. The parameters occurring in these equations have been verified by physiological experiments in many cases.7. In view of the changes of the size-metabolism relation mentioned under (5),Bertalanffy's so-called metabolic and growth types should be considered as ideal cases realizable under certain standard conditions, rather than as invariable characteristics of the species or group of species concerned.8. Seasonal variations of metabolic rates and growth rates seem to show correspondence.9. Urgent problems for further research with respect to each of the basic models are outlined.
Grundbegriffe der quantitativen Biologie des Stoffwechsels
Kurzfassung In der quantitativen Erforschung des Stoffwechsels werden begriffliche Modelle zur Anordnung, Erklärung und Vorhersage der beobachteten Daten benötigt. Vier solcher Modelle werden besprochen, um an Hand dieser die Logik und Methodologie der quantitativen Forschung zu illustrieren. 1. Die Theorie deroffenen Systeme und desFliegleichgewichts, welche eine Erweiterung der konventionellen Kinetik und Thermodynamik erfordert. Sie behandelt die Aufrechterhaltung des Fließgleichgewichts (Umsatzgeschwindigkeiten der Komponenten auf verschiedenen Organisationsstufen) und die Prozesse, die zur Annäherung an diesen Zustand führen. 2. DasRückkopplungs-Modell, das eine weite Anwendung bei biologischen Regulationen finder, aber für dynamische Wechselwirkungen zwischen vielen Prozessen weniger geeignet ist. 3. Das Prinzip derAllometrie, welches das einfachste quantitative Modell der Harmonisierung physiologischer Prozesse darstellt. Das sogenannte Oberflächengesetz ist ein sehr spezieller Fall des Allometrie-Prinzips. Im allgemeinen ist die Allometrie-Beziehung abhängig von der Natur der betrachteten physiologischen Systeme, von physiologischen Zuständen und experimentellen Bedingungen. 4. DasWachstums-Modell nach v.Bertalanffy und Mitarbeitern, das ein einfaches hypothetisch-deduktives System von Wachstums-Gleichungen darstellt. Sein Erklärungs- und Vorhersagewert, ebenso wie seine Grenzen werden im Hinblick auf allgemeine Probleme der quantitativen Biologie diskutiert. Besonderer Nachdruck wird auf die Existenz noch ungelöster und weitere Bearbeitung erfordernder Probleme gelegt.
  相似文献   

18.
Summary This paper deals with the ultrastructure of two types of intranuclear inclusions, microfilamentous spindle-shaped and crystalloid, present in paraventricular nucleus neurons of adult normal rats. These inclusions appear occasionally in some non-secretory neurons of the parvocellular system, but have never been seen in neurosecretory cells of the magnocellular system. The microfilamentous spindle-shaped inclusions show a close spatial relationship with the granulofibrillar body and interchromatin granules.The distribution and functional significance of such structures are discussed in the light of recent ultrastructural and biochemical studies on nuclear inclusions.  相似文献   

19.
Human porphobilinogen synthase [EC.4.2.1.24] is a homo-octamer enzyme. In the active center of each subunit, four cysteines are titrated with 5,5-dithiobis(2-nitrobenzoic acid). Cys122, Cys124 and Cys132 are placed near two catalytic sites, Lys199 and Lys252, and coordinate a zinc ion, referred to as a proximal zinc ion, and Cys223 is placed at the orifice of the catalytic cavity and coordinates a zinc ion, referred to as a distal zinc ion, with His131 . When the wild-type enzymes C122A (Cys122Ala), C124A (Cys124Ala), C132A (Cys132Ala) and C223A (Cys223Ala) were oxidized by hydrogen peroxide, the levels of activity were decreased. Two cysteines were titrated with 5,5-dithiobis(2-nitrobenzoic acid) in the wild-type enzyme, while on the other hand, one cysteine was titrated in the mutant enzymes. When wild-type and mutant enzymes were reduced by 2-mercaptoethanol, the levels of activity were increased: four and three cysteines were titrated, respectively, suggesting that a disulfide bond was formed among Cys122, Cys124 and Cys132 under oxidizing conditions. We analyzed the enzyme-bound zinc ion of these enzymes using inductively coupled plasma mass spectrometry with gel-filtration chromatography. The results for C223A showed that the number of proximal zinc ions correlated to the level of enzymatic activity. Furthermore, zinc-ion-free 2-mercaptoethanol increased the activity of the wild-type enzyme without a change in the total number of zinc ions, but C223A was not activated. These findings suggest that a distal zinc ion moved to the proximal binding site when a disulfide bond among Cys122, Cys124 and Cys132 was reduced by reductants. Thus, in the catalytic functioning of the enzyme, the distal zinc ion does not directly contribute but serves rather as a reserve as the next proximal one that catalyzes the enzyme reaction. A redox change of the three cysteines in the active center accommodates the catch and release of the reserve distal zinc ion placed at the orifice of the catalytic cavity.  相似文献   

20.
A contextualizing image (CI) is a powerful central image of a dream which appears to contextualize (provide a picture-context for) the dreamer's emotion. For instance, dreamers who have experienced any serious traumatic event sometimes dream, I was overwhelmed by a tidal wave. This appears to picture their feeling of terror and/or vulnerability.A scoring system for CIs is examined here and is applied to dreams and daydreams supplied by 40 students. Two raters scoring dreams on a blind basis showed good inter-rater reliability. Recent dreams were shown to have more as well as more intense CIs than recent daydreams; likewise, dreams that stand out had more intense CIs than daydreams that stand out. Students with thin boundaries had more and more intense CIs than students with thick boundaries in their recent dreams and nightmare, but not so clearly in dreams and nightmares that stand out. The emotions judged as contextualized by the powerful images tended towards fear/terror and helplessness/vulnerability in dreams (especially in dreams that stand out) whereas emotions contextualized by images in daydreams showed a wide range with no clusters.  相似文献   

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