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1.
In the preceding paper, using ECEPP, including the effects of water, and the chain build-up procedure, we computed the low energy structures for GnRH and found that there were no distinct low energy structures or structures with high statistical weights. To attempt to deduce possible structures of GnRH that may bind to the GnRH receptor, we computed the low energy structures for GnRH peptides that have l- and d-amino acids substituting for Gly 6. The l-amino acid-substituted peptides (l-Ala and l-Val) have very low or no affinity for the receptor and on activity (release of FSH and LH) while the d-Ala-, d-Leu-, d-Trp- and d-Phe-substituted peptides have significantly higher relative affinities and activities than those for native GnRH; the d-Val-substituted peptide has about one-third of the affinity and activity as native GnRH. Unlike native GnRH, our computations suggest that both sets of peptides form well-defined structures in water: the l-amino acid-substituted peptides are predominantly α-helical while the d-amino acid-substituted peptides adopted E*A A A E D*(C*) A E C A(C*) and minor variants of these structures. By eliminating structures that lay in common to the d-Ala and l-Val peptides and further eliminating structures that differed between the d-Ala and d-Leu peptides, we reduced the number of possible distinct binding conformations to 254. Searching for structures among these 254 conformations that had relative statistical weights that paralleled their relative affinities, we found two candidate structures: D*E A A E C*A E C A and D*G A A E D*A E C G*, both of which have conformations for residues 3–9 that are similar to the computed most probable structures for the d-amino acid-substituted GnRH peptides in water.  相似文献   

2.
In contrast toSarcina maxima D-xylose is not utilized byS. ventriculi as a fermentable substrate,D-Xylose has been found to be a suitable substrate for the selective isolation ofS. maxima.  相似文献   

3.
Algae started colonizing branches of the coral Acropora aspera (Dana) killed by the sea star Acanthaster planci (Linnaeus) within less than 24 hours. Two blue-greens ((Microcoleus lyngbyaceus (Crouan) Ag. and Hormothamnion solutum B. & F.)) dominated the early community but became less abundant than a brown ((Giffordia indica (Sonder) Papenfuss & Chihara)) after 26 days.  相似文献   

4.
Ergoline alkaloids do not belong to a group of physio ogically inert secondary metabolites. Ergometrine as well as ergotamine increased the acetyl-CoA carboxylase activity and inhibited the activities of citrate synthase and isocitrate lyase. The slightly inhibitory effect of ergotamine and stimulatory effect of ergometrine on malate synthase was established. Supplied ergometrine brought about a change in the culture growth rate,i.e. inhibition (10?4 m) or stimulation (10?3 m). Addition of 10?4 m ergometrine to the culture ofClaviceps paspali MG-6 increased the total alkaloid yield by 120%. The stimulatory influence was inversely proportional to the concentration of added alkaloid. It is assumed that accumulating alkaloids suppress attainment of the yield that would be achieved by continuous control of the alkaloid level. A positive relationship is assumed between the process of alkaloid synthesis and the viability of the culture.  相似文献   

5.
Hilgendorf’s (1866) publication on the phylogenyof Planorbis multiformis from Steinheim, Swabian Mountains, is one of the most important contributions of paleontology to early Darwinism. At the same time it helped to lay the foundation for paleontological phylogenetics. Hilgendorf’s unpublished dissertation of 1863, the newly rediscovered collection to his dissertation and the document-file ofHilgendorf’s graduation from Tübingen University help to trace back the origin of Hilgendorf’s ideas.Hilgendorf’s collection contains the oldest phylogenetic tree, which is known so far.  相似文献   

6.
While the unequivocal pattern of endothelial nitric oxide synthase (eNOS) inhibition in cardiovascular control is recognized, the role of NO produced by neuronal NOS (nNOS) remains unclear. The aim of this study was to compare the effects of chronic treatment with 7-nitroindazole (7-NI, nNOS inhibitor) and NG-nitro-l-arginine methylester (l-NAME, general and predominantly eNOS inhibitor) on cardiovascular system of young normotensive rats. Wistar rats (4 weeks old) were used: controls and rats administered either 7-NI (10 mg/kg bw/day) or l-NAME (50 mg/kg bw/day) in drinking water for 6 weeks. The systolic blood pressure (sBP) was measured by plethysmographic method, and the vasoactivity of isolated arteries was recorded. 7-NI-treatment did not affect sBP; however, the sBP was increased after l-NAME-treatment. l-NAME inhibited acetylcholine-induced relaxation of thoracic aorta (TA), whereas it remained unchanged after 7-NI-treatment. The response of TA to sodium nitroprusside was increased in both experimental groups. The expression of eNOS and nNOS in TA was unchanged in both experimental groups, whereas the activity of NOS was decreased in l-NAME-treated group. Noradrenaline- and angiotensin II-induced contractions of TA were reduced in l-NAME-treated group; however, the contractions remained unchanged in 7-NI-treated group. In all groups, the endogenous angiotensin II participated in adrenergic contraction of TA; this contribution was significantly increased in l-NAME-treated group. Neurogenic contractions in mesenteric artery (MA) remained unchanged after 7-NI-treatment, but increased after l-NAME-treatment. Results show that NO deficiency induced by administration of 7-NI and l-NAME had different cardiovascular effects: eNOS and nNOS triggered distinct signaling pathways in young normotensive rats.  相似文献   

7.
Significant reductions of the average densities of 7 Diptera:Musca domestica L.,Muscina stabulans (Fallen),Fannia canicularis (L.),F. femoralis (Stein),Ophyra leucostoma (Wiedemann),Stomoxys calcitrans (L.), andPhaenicia spp. were attained over a 20-month period on poultry ranches that were under supervision in southern California by favoring the natural increase of predatory and scavenger arthropods and by periodic inoculative releases of 4 parasitic Hymenoptera. The importance of a long range management plan is emphasized. Releases of parasitic Hymenoptera during spring months had an apparent greater direct effect on fly population reduction than did similar releases in the summer. Autumn releases were not evaluated through a temporary ban on sampling breeding habitats in the wake of a Newcastle Disease outbreak. The importance of habitat stability and exotic importations of beneficial species are discussed.  相似文献   

8.
Partly purified membranes (with plasmalemma material) of Acetabularia mediterranea were studied with respect to ATPase activity in alkali- and Ca++-free media and its sensitivity to pH (5 – 9), oligomycin (200 ?g/mg protein), 100 ?M N-N′-dicyclohexylcarbodiimide (DCCD), and 50 ?M vanadate. Besides activities which may originate from mitochondrial H+ ATPase (oligomycin-sensitive, alkaline pH optimum) and tonoplast H+ ATPase (DCCD-sensitive, pH optimum 7.5), there is ATPase activity with a pH optimum around pH 6.5, sensitive to vanadate and insensitive to DCCD. These results strongly suggest that the electrogenic Cl? pump in the plasmalemma of Acetabularia is an ATPase. Effects of Mg++, Mg-ATP, ADP, GTP, UTP, CTP and HCO3 ? versus Cl? on this ATPase activity are described.  相似文献   

9.
Over-exposure to manganese (Mn) has been known to induce endoplasmic reticulum (ER) stress involving protein misfolding. The proper maturation and folding of native proteins rely on the activity of protein disulfide isomerase (PDI). However, the exact mechanism of Mn-induced alpha-synuclein oligomerization is unclear. To explore whether alpha-synuclein oligomerization was associated with S-nitrosylation of PDI, we made the rat brain slice model of manganism and pretreated slices with l-Canavanine, a selective iNOS inhibitor. After slices were treated with Mn (0, 25, 100, and 400 μM) for 24 h, there were dose-dependent increases in apoptotic percentage of cells, lactate dehydrogenase (LDH) releases, production of NO, inducible nitric oxide synthase (iNOS) activity, the mRNA and protein expressions of iNOS, and PDI. Moreover, S-nitrosylated PDI and alpha-synuclein oligomerization also increased. However, there was a significant increase in the PDI activity of 25-μM Mn-treated slices. Then, PDI activity and the affinity between PDI and alpha-synuclein decreased significantly in response to Mn (100 and 400 μM), which was associated with S-nitrosylation of PDI. The results indicated that S-nitrosylated PDI could affect its activity. We use the l-Canavanine pretreatment brain slices to inhibit S-nitrosylation of PDI. The results showed that l-Canavanine pretreatment could reduce Mn-induced nerve cell injury and alpha-synuclein oligomerization. Additionally, there was a significant recovery in PDI activity in l-Canavanine-pretreated slices. The findings revealed that Mn induced nitrosative stress via the activation of iNOS and subsequent S-nitrosylation of PDI in cultured slices. Moreover, S-nitrosylation of PDI is an important signaling event in the Mn-induced alpha-synuclein oligomerization in brain slices.  相似文献   

10.
11.
European green hydra,Chlorohydra viridissima (Pallas) were tested for adaptability and predation effectiveness in natural habitats ofAedes nigromaculis (Ludlow) andCulex tarsalis Coquillet in Kern County, California from June through December, 1973. Hydra were well adapted to all habitats except Kern River seepage where their adaptability was measured at only 55.6%.Aedes nigromaculis populations were reduced 67.2% in an irrigated pasture in July.Culex tarsalis densities were reduced 33.9% in standing Kern River seepage and 79.2% in duck club ponds from September through December, 1973. TheC. tarsalis larval density in hydra treated duck club ponds remained below an average of 0.5/dip after inoculation in September. Hydra density increased at inoculation sites and significant numbers overwintered at Riverside, California without food. The practical utilization of hydra and their attributes for mosquito control are discussed.  相似文献   

12.
To investigate the mechanism of apoptosis in myocardial cells of aging rats induced by d-galactose and to study the effect of the Polysaccharide isolated from the seeds of Cuscuta chinensis Lam (PCCL) on apoptosis of cardiomyocytes and its corresponding machinasim in aging rat model. Fifty male SD rats were randomly divided into 5 groups. Normal control group (NC). d-galactose (100 mg·kg?1d?1 for 56 day) indued aging group (MC), d-galactose plus 100 mg kg?1 d?1 PCCL group (ML), d-galactose plus 200 mg kg?1 d?1 PCCL group (MM), and d-galactose plus 400 mg kg?1 d?1 PCCL group (MH). Same volume of solution (water, or PCCL aqueous solution) was given by gavage for 56 days. Then the hearts were collected and apoptosis parameters were evaluated. Caspase-3 and Cyt c were determined by fluorescence spectrometer, the apoptosis rate was assessed by AnnexinV-FITC method by Flow-Cytometry, [Ca2+]i and [Ca2+]i overloaded by KCL were observed by laser scanning confocal microscopy (LSCM); Bcl-2 and Bax were examined by immunohistochemistry. The content of Cyt C, [Ca2+]i of cardiomyocytes, the activity of Caspase-3, Bax expression level in d-galactose induced aging group were higher than NC (p < 0.05). The ratio of Bcl-2/Bax was decreased in d-galactose induced aging group compared to NC. On the other hand, the content of Cyt C, [Ca2+]i of cardiomyocytes, the activity of Caspase-3 and apoptosis rate, as well as Bax expression level in all three PCCL groups were decreased compared to galactose induced group (p < 0.05). Bcl-2/Bax ratio was increased in all PCCL groups compared to galactose induced aging group. PCCL could decrease the apoptosis of cardiomyocytes by the mitochondria apoptosis pathway.  相似文献   

13.
Karyotypes ofTragopogon orientalis L. subsp.orientalis, T orientalis L. subsp.leiocarpos (Sauter)Trnka,T. pratensis L.,T. minor Miller,T. dubius Scop. subsp.dubius andT. dubius Scop. subsp.major (Jacq.)Vollmann were studied. The occurrence in Slovakia ofT. pratensis was karyologically proved.  相似文献   

14.
15.
O. Bakkendorf 《BioControl》1970,15(2):153-155
The autor describes a new species,Anaphes lemae, reared fromOulema (Lema) spp in France, Yugoslavia, and Poland and shows a misidentification ofPatasson valkenburgica Soyka. He points out the existence ofPatasson declinata Soyka in Poland and the Netherlands.  相似文献   

16.
Strain DCY84T, a Gram-stain positive, rod-shaped, aerobic, spore-forming bacterium, motile by means of peritrichous flagella, was isolated from humus soil from Yongin forest in Gyeonggi province, South Korea. Strain DCY84T shared the highest sequence similarity with Paenibacillus barengoltzii KACC 15270T (96.86 %), followed by Paenibacillus timonensis KACC 11491T (96.49 %) and Paenibacillus phoenicis NBRC 106274T (95.77 %). Strain DCY84T was found to able to grow best in TSA at temperature 30 °C, at pH 8 and at 0.5 % NaCl. MK-7 menaquinone was identified as the isoprenoid quinone. The major polar lipids were identified as phosphatidylethanolamine, an unidentified aminophospholipid, two unidentified aminolipids and an unidentified polar lipid. The peptidoglycan was found to contain the amino acids meso-diaminopimelic acid, alanine and d-glutamic acid. The major fatty acids of strain DCY84T were identified as branched chain anteiso-C15:0, saturated C16:0 and branched chain anteiso-C17:0. The cell wall sugars of strain DCY84T were found to comprise of ribose, galactose and xylose. The major polyamine was identified as spermidine. The DNA G+C content was determined to be 62.6 mol%. After 6 days of incubation, strain DCY84T produced 52.96 ± 1.85 and 72.83 ± 2.86 µg/ml l-indole-3-acetic acid, using media without l-tryptophan and supplemented with l-tryptophan, respectively. Strain DCY84T was also found to be able to solubilize phosphate and produce siderophores. On the basis of the phenotypic characteristics, genotypic analysis and chemotaxonomic characteristics, strain DCY84T is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus yonginensis sp. nov. is proposed. The type strain is DCY84T (=KCTC 33428T = JCM 19885T).  相似文献   

17.
Using moving boundary electrophoresis in a veronal buffer, pH 8·5, of 0·05 ionic strength and at 4·3 mA, we succeeded in separating the inhibitor, which was obtained by fractionation on a Sephadex G-50 column, into four components. The two most substantial components represent 25% and 65% respectively from the separated proteins as a whole. The heterogeneity of the inhibitor was proved by analytical ultracentrifugation, too. The ionex chromatography was applied for the quantitative separation of the inhibitor. We used ionex chromatography on DEAE Cellulose the concentration gradient being 0–1m NaCl in a 0·01m phosphate buffer, pH 7·3, and on DEAE Sephadex A-50 using the same concentration gradient in a phosphate buffer, of 0·1 ionic strength and pH 7·3. In both cases four components were obtained. The most substantial component, representing 65% of the whole analysed material, was eluted at the concentration 0·15–0·3m NaCl, and was electrophoretically homogenous and showed the most effective inhibitory ability.  相似文献   

18.
Seasonal predatory and scavenger arthropod densities were studied at interior and coastal southern California poultry ranches. Though some seasonal population clumping occurred with some species, the distribution of predators and scavengers was fairly uniform within each ranch. Correlation analyses of key predators in theHisteridae, Staphylinidae, Hydrophylidae andDermaptera with the potential hosts,Musca domestica L.,Tinea fuscipunctella Haworth, andFannia spp. suggested that predator activity was seasonally influenced. Possible periodic avoidance of a particular host's habitat was detected as significant negative correlations. The data tend to support the importance of different species of predators in different seasons and the need for natural enemy complexes rather than single species for biological control.  相似文献   

19.
The bookK. Richter, Plantae europeae, Vol. 1, 1890, is analyzed from the viewpoint of nomenclature of subspecies names. 264 subspecies names interesting from the standpoint of contemporary taxonomy and nomenclature are selected from the total number of 840 subspecies names for a commented list. Seventeen important cases are dealt with separately in greater detail. Eleven new nomenclatural combinations (two for species, nine for subspecies) are proposed in the Appendix. Types for two generic names (Acorellus Palla andJuncellus C. B. Clarke) are proposed. A new term “parabasionym” is applied for names establishing the priority of infraspecific epithets in the rank in question. The need to respect the newly accepted principle of priority of autonymic subspecies names at proposing new nomenclatural combinations is stressed. Examples ofRichter’s subspecies names having priority, subspecies names with necessary changes in their authorship and names having a possible importance as parabasionyms are enumerated in separate lists.  相似文献   

20.
Mechanisms of Na+ uptake, ammonia excretion, and their potential linkage were investigated in three characids (cardinal, hemigrammus, moenkhausia tetras), using radiotracer flux techniques to study the unidirectional influx (J in), efflux (J out), and net flux rates (J net) of Na+ and Cl?, and the net excretion rate of ammonia (J Amm). The fish were collected directly from the Rio Negro, and studied in their native “blackwater” which is acidic (pH 4.5), ion-poor (Na+, Cl? ~20 µM), and rich in dissolved organic matter (DOM 11.5 mg C l?1). J in Na , J in Cl , and J Amm were higher than in previous reports on tetras obtained from the North America aquarium trade and/or studied in low DOM water. In all three species, J in Na was unaffected by amiloride (10?4 M, NHE and Na+ channel blocker), but both J in Na and J in Cl were virtually eliminated (85–99 % blockade) by AgNO3 (10?7 M). A time course study on cardinal tetras demonstrated that J in Na blockade by AgNO3 was very rapid (<5 min), suggesting inhibition of branchial carbonic anhydrase (CA), and exposure to the CA-blocker acetazolamide (10?4 M) caused a 50 % reduction in J in Na .. Additionally, J in Na was unaffected by phenamil (10?5 M, Na+ channel blocker), bumetanide (10?4 M, NKCC blocker), hydrochlorothiazide (5 × 10?3 M, NCC blocker), and exposure to an acute 3 unit increase in water pH. None of these treatments, including partial or complete elimination of J in Na (by acetazolamide and AgNO3 respectively), had any inhibitory effect on J Amm. Therefore, Na+ uptake in Rio Negro tetras depends on an internal supply of H+ from CA, but does not fit any of the currently accepted H+-dependent models (NHE, Na+ channel/V-type H+-ATPase), or co-transport schemes (NCC, NKCC), and ammonia excretion does not fit the current “Na+/NH4 + exchange metabolon” paradigm. Na+, K+-ATPase and V-type H+-ATPase activities were present at similar levels in gill homogenates, Acute exposure to high environmental ammonia (NH4Cl, 10?3 M) significantly increased J in Na , and NH4 + was equally or more effective than K+ in activating branchial Na+,(K+) ATPase activity in vitro. We propose that ammonia excretion does not depend on Na+ uptake, but that Na+ uptake (by an as yet unknown H+-dependent apical mechanism) depends on ammonia excretion, driven by active NH4 + entry via basolateral Na+,(K+)-ATPase.  相似文献   

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