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1.
Summary This paper deals with the ultrastructure of two types of intranuclear inclusions, nuclear bodies and membranous lamellar bodies, present in hypothalamic pericytes of intact adult rats. The nuclear bodies exhibited simple and granular forms, whereas the membranous lamellar bodies were entirely made up of myelin-like membrane whorls.The occurrence of these bodies in nuclei of pericytes has never been previously reported. The origin and functional meaning of such structures is discussed in the light of recent ultrastructural and biochemical studies on nuclear inclusions.  相似文献   

2.
Recruitment of the protein kinase C (PKC) family of isozymes is an integral component of the signaling events that direct cardiac phenotype expressed during postnatal development and in response to pathologic stimuli. Hyperglycemia is a potent activating signal for cardiac PKC isozymes and induces the apoptosis program in cardiac muscle cells. To determine whether cardiac PKC isozymes modulate transmission of the hyperglycemia apoptosis signal, we have employed isozyme-specific peptide modulators to selectively inhibit (PKC I/II, and ) or activate (PKC). PKC peptides were delivered to primary cultures of serum starved adult rat ventricular myocytes (ARVM), by conjugation to the homeodomain of drosophila antennapedia. As expected, hyperglycemia induced a 35% increase in ARVM apoptosis. Peptide inhibitors of PKC I/II and blocked transmission of the hyperglycemia apoptosis signal, whereas the isozyme specific inhibitor of PKC (V1-2) did not alter the magnitude of glucose-induced ARVM apoptosis. Alternatively, the PKC translocation activator (RACK) abolished hyperglycemia-induced apoptosis, strongly suggesting a cardioprotective role for PKC in this system. Therefore, we conclude that cardiac PKC isozymes modulate hyperglycemia-induced apoptosis and activation of cardiac PKC protects ARVM from the hyperglycemia-induced death signal. (Mol Cell Biochem 268: 169–173, 2005)  相似文献   

3.
Summary Interaction of the RecA protein with single-stranded DNA (ssDNA) was analyzed by challenge with the hydroxyl radical, which can cleave the DNA backbone. We found that RecA protein induces cleavage by the radical at a defined distance from the 5 end. The cleavage was at the 11th nucleotide in many oligodeoxynucleotides. Cleavage may be intermittent since a second cleavage was induced at the 22nd or 21st site. This specific cleavage was observed under optimal conditions for filament formation, homologous pairing and strand exchange. Specificity in cleavage was, however, decreased by replacement of ATP by adenosine 5-(-thio)triphosphate (ATPS), replacement of RecA protein by a mutant (RecAl) protein, or an increase in Mg2– concentration. We propose that RecA protein induces a special structural alteration, such as bending, perhaps sequentially, on ssDNA and that this altered site plays an important role in homologous pairing and strand exchange.Abbreviations ssDNA single-stranded DNA - dsDNA doublestranded DNA - ATPS adenosine 5-(-thio)triphosphate Deceased  相似文献   

4.
Summary -Cyclodextrin(-CD) was produced by cyclodextrin glycosyltransferase(CGTase) in aqueous two-phase system. -CD production from soluble starch was catalyzed by CGTase in dextran-rich bottom phase, and the -CD produced was transferred to PEG-rich top phase in aqueous two-phase system, composed of 7% (w/w) polyethylene glycol(Mr 20,000) and 10% (w/w) dextran(Mr 38,900). Partition coefficients of -CD and CGTase were 1.5 and 0.25, respectively. The total productivity of -CD in aqueous two-phase system was about 3 times of that in dextran phase.  相似文献   

5.
Four glycosidases were analyzed in 10 mm apical segments prepared from growing roots (15 mm) of Zea mays L. The pH optima were found to be 5.8 for -glucosidase, 4.4 for -galactosidase, 6.4 for -glucosidase and 6.0 for -galactosidase. The -glucosidase showed 4-fold higher activity than the -galactosidase. The distribution of the -glucosidase activity was signifcantly different from that of the -galactosidase, -glucosidase and -galactosidase.Abbreviations -Glu -glucosidase - -Gal -galactosidase - -Glu -glucosidase - -Gal -galactosidase  相似文献   

6.
Summary Colocalization of calcitonin gene-related peptide (CGRP) and protein kinase C -subtype (PKC-) like immunoreactivities (LI) and the subcellular localization of CGRP-LI were studied in the ventral horn of rat spinal cord. Ultrastructurally CGRP-LI was localized on the membranes of the Golgi-complexes, in multivesicular bodies and in vesicles adjacent to the Golgi-complex in motoneuron perikarya. The colocalization of PKC- and CGRP-LI was detected in most of the ventral horn motoneurons. However, few motoneurons were only PKC--immunoreactive. These results suggest that PKC- may be involved in the regulation of CGRP release from motoric axon terminals.  相似文献   

7.
Ionic relations of aeroponically-grown olive genotypes,during salt stress   总被引:1,自引:1,他引:0  
Two olive (Olea europaea L.) genotypes, Frantoio and Leccino, were exposed to increasing concentrations of NaCl (0-30-60-120 mM) in an aeroponic cultivation system for 60 days. Dry weights and sodium and potassium contents of apical and basal leaves, new and old wood, and roots were measured to determine Na uptake rate, Na translocation rate and K-Na selectivity ratio (SK,Na). Frantoio showed a higher salt resistance than Leccino. Frantoio and Leccino had a similar Na uptake rate, but largely differed for Na translocation to the shoot. Furthermore Frantoio exhibited a higher K-Na selectivity than Leccino at both whole plant level and above all at the level of shoot system. Resistance mechanism of Frantoio is probably related to Na esclusion by roots and to the ability to maintain an appropriate K/Na ratio in actively growing tissues.Research supported by National Research Council of Italy, Special project RAISA.  相似文献   

8.
The de novo induction of roots in tomatoes (Lycopersicon esculentum) Mill. cvs. Earlypak-7, Ace, Better Boy, Roma, and Parks' Whopper by fumonisin B1, a mycotoxin produced by Fusarium moniliforme J. Sheld., was studied. In graded dosages of fumonisin B1, detached stems of the cultivars Ace, Better Boy, and Roma were induced to produce calluses and roots earlier than controls. The cultivar Ace was especially responsive to this mycotoxin, and following a single application, callus initiation was observed to occur within a 24–48-h period and roots were produced as early as 72 h with 10 g/shoot or as late as 96 h with low dosages. The control plants of all cultivars were completely negative for a rooting response during this time. Some cultivars treated with fumonisin B1 showed either no response or developed signs of phytotoxicity. Those cultivars that were stimulated to produce roots did not show signs of phytotoxicity, except at dosages of 0.5 mg/plant and higher. One cultivar did not show any signs of phytotoxicity nor was it induced to root. The ability of fumonisin B1 to affect the accumulation of calcium in other systems, and its structural similarity to sphingosine suggest that the induction of adventitious roots may be a calcium-dependent process.  相似文献   

9.
    
Summary If X174-infected cells are UV irradiated about 3 min after the onset of phage development, host cell reactivation (HCR) of the intracellular phage can be demonstrated. HCR of X174 can be observed only in host bacteria able to reactivate phages T1 and . Like with these two phages, HCR in X174 can be inhibited by caffeine.Since no HCR can be observed if X174 is irradiated extracellularly or immediately after infection, it seems likely that only UV damage to the double stranded replicative form of X174 can be repaired by HCR.With 4 Figures in the Text  相似文献   

10.
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   

11.
Summary Dehydrocholic acid (3,7,12-trioxo-5-cholanic acid) (0.5% concentration) was completely and selectively reduced to 12-ketoursodeoxycholic acid (3, 7-dihydroxy-12-oxo- 5-cholanic acid) in a membrane reactor by means of 3-hydroxysteroid dehydrogenase and 7-hydroxysteroid dehydrogenase. Coenzyme regeneration was carried out with the glucose-glucose dehydrogenase system.  相似文献   

12.
Steryl glycosides are the predominant form of sterol at 88% of the total sterol in non-betalain producing calli of Beta vulgaris. The total sterol decreases and sterol form shifts from steryl glycosides to 97% free sterol upon the transition of non-betalain to betalain producing calli. A substantial decrease in stigmasterol (24--ethylcholesta-5,22E-dien-3-ol) and sitosterol (24-ethylcholest-5-en-3-ol) levels is observed during this transition, and alters the ratio of 7:5 sterols. Spinasterol (24- ethyl-5-cholesta-7,22E-dien-3-ol) is the dominant sterol at 43% and 95% of the total sterol in non-betalain producing and betalain producing calli. The level of 22-dihydrospinasterol (24-ethyl-5-cholest-7-en-3-ol) is reduced in both calli to 3% from 25% in leaves. Lanosterol (4,4,14-trimethyl-cholesta-8(9),24-dien-3-ol) and cycloartenol (9,19-cyclopropyl-4,4,14-trimethyl-cholest-24-en-3-ol) were identified in betalain and nonbetalain producing callus respectively.  相似文献   

13.
Photoaffinity labeling by 3-O-(4-benzoyl)benzoyl adenosine 5-triphosphate (BzATP) of the adenine nucleotide binding site(s) on isolated and complexed and subunits of F1-ATPase from the thermophilic bacterium PS3 (TF1) is described. BzATP binds to both isolated and subunits, to complexed subunit but not to complexed subunit. Amino acid sequence determination of radiolabeled peptides obtained by proteolytic digestion of [-32P]BzATP-labeled subunit indicates that residues on both the amino-terminal (residues A41-E67) and carboxy-terminal (residues Q422–Q476) were modified by BzATP. One of the residues in the carboxy-terminal modified by BzATP is most probably Q422. Although the binding stoichiometry of 1 mol of BzATP incorporated by either isolated or complexed subunit was maintained, the spatial conformation of the polypeptide determines which amino acid residue(s) is more accessible to the reactive radical. CNBr derived fragments G10-M64, E75-M233, and D390-M469 were labeled with the isolated subunit. With complexed subunit the label was found only in CNBr fragments: E75-M233 and G339-M389. The locations where the covalently bound BzATP was found, in the soluble and assembled subunits, indicate that different conformational states exist. In the isolated form of the and subunits the amino- and carboxy-termini can fold and reach the central domain of the polypeptide, the domain containing the adenine nucleotide binding site. When combines with to form the 33 core complex the new conformation of the subunits is such that covalent labeling by BzATP of and of the amino terminal of subunit is excluded.  相似文献   

14.
On age morphological changes of males of Chydoridae (Cladocera)   总被引:2,自引:2,他引:0  
N. N. Smirnov 《Hydrobiologia》1967,30(3-4):555-571
Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus.  相似文献   

15.
Chicken - and -lipovitellin are derived from parent vitellogenin proteins and contain four subunits (125, 80, 40, and 30 kDa) and two subunits (125 and 30 kDa), respectively. Metal analyses demonstrate both are zinc proteins containing 2.1 ± 0.2 mol of zinc/275 kDa per -lipovitellin and 1.4 ± 0.2 mol of zinc/155 kDa per -lipovitellin, respectively. The subunits of -lipovitellin, Lv 1 (MW 125 kDa) and Lv 2 (MW 30 kDa), are separated by gel exclusion chromatography in the presence of zwittergent 3–16. Zinc elutes with Lv 1, suggesting that this subunit binds zinc in the absence of Lv 2. The subunits of - and -lipovitellin were separated by SDS-PAGE, digested with trypsin, and mapped by reverse-phase HPLC. The peptide maps of the 125-kDa subunits from - and -lipovitellin are essentially identical. Similar results are obtained for the 30-kDa subunits of both lipovitellins. The sequences of five and four peptides of the 125-kDa subunit of - and -Lv, respectively, and two peptides of the 30-kDa subunit of - and -lipovitellin were determined and match those predicted from the gene for vitellogenin II, Vtg II. Comparison of the amino acid composition of the 125- and 30-kDa subunits of - and -lipovitellin support the conclusion that they originate from the same gene. The sequences of peptides from the 80- and 40-kDa subunits of -lipovitellin have not been found in the NCBI nonredundant data bank. The 27-amino acid N-terminal sequence of the 40-kDa protein is 56% similar to the last third of the Lv 1-coding region of the Vtg II gene, suggesting it may come from an analogous region of the Vtg I gene. We propose a scheme for the precursor—product relationship of Vtg I.  相似文献   

16.
Occupational exposure to beryllium (Be) and Be compounds occurs in a wide range of industrial processes. A large number of workers are potentially exposed to this metal during manufacturing and processing, so there is a concern regarding the potential carcinogenic hazard of Be. Studies were performed to determine the carcinogenic potential of beryllium sulfate (BeSO4) in cultured mammalian cells. BALB/c3T3 cells were treated with varying concentrations of BeSO4 for 72 h and the transformation frequency was determined after 4 weeks of culturing. Concentrations from 50–200 g BeSO4/ml, caused a concentrationdependent increase (9–41 fold) in transformation frequency. Nontransformed BALB/c3T3 cells and cells from transformed foci induced by BeSO4 were injected into both axillary regions of nude mice. All ten Beinduced transformed cell lines injected into nude mice produced fibrosarcomas within 50 days after cell injection. No tumors were found in nude mice receiving nontransformed BALB/c3T3 cells 90 days postinjection. Gene amplification was investigated in Kras, cmyc, cfos, cjun, csis, erbB2 and p53 using differential PCR while random amplified polymorphic DNA fingerprinting was employed to detect genomic instability. Gene amplification was found in Kras and cjun, however no change in gene expression or protein level was observed in any of the genes by Western blotting. Five of the 10 transformed cell lines showed genetic instability using different random primers. In conclusion, these results indicate that BeSO4 is capable of inducing morphological cell transformation in mammalian cells and that transformed cells induced by BeSO4 are potentially tumorigenic. Also, cell transformation induced by BeSO4 may be attributed, in part, to the gene amplification of Kras and cjun and some BeSO4induced transformed cells possess neoplastic potential resulting from genomic instability.  相似文献   

17.
The present study was undertaken to determine the effects of AT1 receptor blockade which occurred in response to losartan, on the extracellular matrix (ECM) degradation process in the Bio 14.6 (n = 12) and Bio 53.58 (n = 12) strains which are referred as models of hypertrophic and dilated cardiomyopathy, respectively. The administration of losartan (30 mg/kg/day) in hamsters from 10–20 weeks of age reduced the accumulation of the left ventricular collagen matrix in both of the Bio 14.6 and the Bio 53.58 strains. According to the RTPCR, the levels of mRNA for matrix metalloproteinase (MMP) and the tissue inhibitor of MMP (TIMP) were examined. MMP1, 2, 3, and 9 were more enhanced in both myopathic strains than in the control F1 strains. With losartan, the levels of MMP1, 2, 9, TIMP1 and 2 decreased in the both strains but those for MMP3 did not in Bio 14.6 strains. TIMP3 and 4 mRNA levels did not change in any of the experimental hamsters, whether treated or untreated with losartan. The Western blots also showed similar observations in the both strains as seen in mRNA expressions although MMP2 in the Bio 53.58 strains did not differ between treated and untreated with losartan. Although losartan has an inhibitory effect on collagen accumulation in the development of cardiomyopathy, MMPs (1, 2, 9) and TIMPs (1, 2) seem to be susceptible to responding to losartan in Bio cardiomyopathic hamsters.  相似文献   

18.
N1 (= Nijmegen 1) D. melanogaster heterozygous for sparkling poliert (4) (= pol, here) were backcrossed as single pairs. When were not selected for departure from 1/1, pol/pol +, many exceptional ratios were observed even though the net for all 67 pairs was approximately one-to-one; in the same experiment a net excess of was observed. In a second experiment were selected for departure from 1/1, pol/pol +ratios. The net pol/pol +ratios became significantly different from the 1/1 expected but the sex ratio approached normal. Lineage of the males in the second experiment were recorded and displayed as pedigrees. These together with tabulated data suggest that in some pairs, one of the four categories pol , pol , pol +, pol + may be significantly greater or less than 1/4 of the total offspring recovered.  相似文献   

19.
Intracerebroventricular (i.c.v.) choline (50–150 g) increased blood pressure and decreased heart rate in spinal cord transected, hypotensive rats. Choline administered intraperitoneally (60 mg/kg), also, increased blood pressure, but to a lesser extent. The pressor response to i.c.v. choline was associated with an increase in plasma vasopressin. Mecamylamine pretreatment (50 g; i.c.v.) blocked the pressor, bradycardic and vasopressin responses to choline (150 g). Atropine pretreatment (10 g; i.c.v.) abolished the bradycardia but failed to alter pressor and vasopressin responses. Hemicholinium-3 [HC-3 (20 g; i.c.v.)] pretreatment attenuated both bradycardia and pressor responses to choline. The vasopressin V1 receptor antagonist, (-mercapto-, -cyclopenta-methylenepropionyl1, O-Me-Tyr2, Arg8)-vasopressin (10 g/kg) administered intravenously 5 min after choline abolished the pressor response and attenuated the bradycardia-induced by choline. These data show that choline restores hypotension effectively by activating central nicotinic receptors via presynaptic mechanisms, in spinal shock. Choline-induced bradycardia is mediated by central nicotinic and muscarinic receptors. Increase in plasma vasopressin is involved in cardiovascular effects of choline.  相似文献   

20.
Summary We have studied the reactions between adenosine 5-phosphorimidazolide and 9-(2-amino-2-deoxyxylofuranosyl) adenine (I) or 3-methylamino-3-deoxyadenosine (II), both with and without a poly (U) template. We find that both amino compounds react much more rapidly than does adenosine, in the absence of a template. The rate of reaction is greatly enhanced by a poly (U) template in the case of I, but the enhancement is slight in the case of II.Abbreviations A adenosine - xylo ANH2 9-(2-amino-2-deoxy--D-xylofuranosyl) adenine - ANHMe 3-methylamino-3-deoxyadenosine - ImpA adenosine 5-phosphorimidazolide - A3 pA adenylyl-[35]-adenosine - A2 pA adenylyl-[25]-adenosine - UNPA adenylyl-[52]-2-amino-2-deoxyuridine - xylo ANPA 9-[adenylyl-(52)-2-amino-2-deoxy--D-xylofuranosyl]adenine - A(NMe)pA adenylyl-[53]-3-methylamino-3-deoxyadenosine - pA adenosine 5phosphate - AppA P1, P2-diadenosine 5pyrophosphate - (pA)n n = 2, 3 [2-5]-linked oligomers of pA - A2 pA2 pA [2-5]-linked trinucleoside diphosphate of A - poly (U) polyuridylic acid  相似文献   

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