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1.
Glycerol, injected into a site between the femoral vessels of the rat, induced neovascularization, both from the preexisting microcirculation and from the side of the femoral vein facing the artery-vein interstitium where the glycerol was administered. The use of glycerol together with a known angiogenic substance (PGE2) did not modify the neocapillary density (NCD) obtained with glycerol alone. In contrast, the lower level of NCD achieved with an acylglycerol (triacetylglycerol) was increased when the latter was associated with PGE2. Values reached were similar to, but never higher than, those for glycerol alone, or combined with PGE2. The results suggest that glycerol and some substances containing glycerol, amongst which 1-butyrylglycerol has been previously considered1, may stimulate angiogenesis by a direct or indirect mechanism of action.  相似文献   

2.
Glycerol production byDunaliella   总被引:1,自引:0,他引:1  
Summary Species of the unicellular algaDunaliella possess outstanding tolerance of a wide range of salinities. They can adapt to grow in salt media which range from less than 0.5 M to saturated salt solutions and withstand enormous osmotic shocks through a unique osmotic adaptation. The osmoregulating mechanism depends on photosynthetic production of glycerol, whose intracellular concentration varies in direct proportion to the extracellular salt concentration and reaches values in excess of 50% of the total dry weight of the cells.Dunaliella, and another halotolerant glycerol producing alga,Asteromonas gracilis, osmoregulate biochemically by controlling glycerol biosynthesis and degradation. 3 new enzymes, NADPH-dihydroxyacetone-reductase, dihydroxyacetone kinase and glycerol-1-phosphatase seem to be involved in the osmoregulatory response via glycerol inDunaliella andAsteromonas. A hypothetical scheme of glycerol metabolism in these algae utilizing these enzymes is presented. Growth studies ofDunaliella indoors and outdoors showed that salt concentrations favoring maximal glycerol productivity are not identical with those required for maximal algal productivity. Maximal yield of glycerol occurred around 2 M NaCl while maximal algal productivity occurred below 0.5 M NaCl. Observed yields of glycerol inDunaliella culture outdoors are compared with theoretically calculated maximal yield.  相似文献   

3.
Cephalopods typically have high metabolic rates. They have blood in which the oxygen carrier is haemocyanin, a pigment that is found only in solution and which never seems to be present in concentrations that will transport more than 4–5 vols % of oxygen. Their hearts must in consequence have very high cardiac outputs. In this account the performance of the heart ofNautilus, the only surviving ectocochleate, is contrasted with the performance of the hearts of coleoids,Octopus which has a relatively low metabolic rate (for a coleoid) and squids which have very high oxygen uptakes by any standards. In all these animals, heartbeat frequency is temperature-dependent and the additional oxygen demand in exercise is met very largely by a 2–3-fold increase in stroke volume. With the exception ofNautilus, cephalopods tend to utilise nearly all of the oxygen transported in the blood even at rest; they show very limited factorial scopes. Specific power output has, however, increased dramatically from 2.7 mWg–1 in an activeNautilus to 5.5 mWg–1 inOctopus and up to 20 or 30 mWg–1 in species ofLoligo. The increase is almost entirely due to a 10-fold increase in heartbeat frequency. It is argued that frequency cannot be used as a means of responding to extra demand in an animal that must also carry automatic compensation for changes in metabolic rate dependent upon the ambient temperature, and that the use of frequency in some squid may be associated with a reduced temperature tolerance. Cephalopod systemic hearts do not scale directly with body mass, like the hearts of fish and the higher vertebrates. Smaller cephalopods have relatively larger hearts (as Mass0.9). A typical 100-g coleoid would have a heart mass of 0.15 g. Oegopsid squids appear to be exceptional with hearts twice as large.  相似文献   

4.
Summary The hitherto unknown compounds 5-(2-pyridyl)thiazole, 2-(2-thienyl)pyridine and methyl--picolyl sulphide have been synthesized. The structure of all three substances allows the formation of a chelate ring with N and S as ligand atoms. 5-(2-Pyridyl)thiazole yields with Fe2+ at a pH of 2.5 a significant change in absorption, which is attributed to chelate formation.  相似文献   

5.
Summary Mature chloroplasts ofClivia miniata etBilbergia sp. show the intensive incorporation of thymidine3H into DNA and uridine3H into RNA. On the contrary, phenylalanine3H is mostly incorporated in the proplastids.  相似文献   

6.
Summary (1 R) [1-3H,2H1] 3-Phenylpropanol, the key intermediate in the synthesis of (4 R) [4-3H,2H1] D, L-homoserine and of the (4 S)-isomer, is obtained from (1 S) [1-2H1] 3-phenylpropanol and (1 RS) [1-3H] ethanol upon incubation with yeast alcohol dehydrogenase and NAD+; under similar conditions 2-phenylethanol undergoes very small exchange with [1-2H2] ethanol.  相似文献   

7.
Incubation of molting glands from the crayfishProcambarus clarkii (Y-organ) and the silkwormBombyx mori (prothoracic gland) with 23,24-[2H4]-2-deoxyecdysone resulted in the production of deutero-ecdysone; this biotransformation was inhibited in the presence of xanthurenic acid. When the experiments were performed under an18O2 atmosphere, the18O atom was introduced into ecdysone, as confirmed by mass spectrometry. We therefore suggest that xanthurenic acid inhibits P-450-dependent hydroxylation of 2-deoxyecdysone. However, deutero-2-deoxyecdysone was not converted to 3-dehydroecdysone when using Y-organs in vitro, although it is a major product. We therefore conclude that the biosynthetic pathway of ecdysteroids inP. clarkii branches at an early step.  相似文献   

8.
Summary [7,7-3H2]Clionasterol was synthesized and fed, together with [4-14C]sitosterol, toTenebrio molitor larvae; fucosterol and isofucosterol, recovered from the sterol fraction were found to be doubly labeled, indicating that clionasterol is converted into both the ethylidenic compounds.  相似文献   

9.
Summary Smooth muscle, treated with 50% glycerol solution at 27°C for 20 min, contracted on the application of Ca2+ or Mg2+. The briefly glycerinated smooth muscle can be used as a model system of smooth muscle contraction.  相似文献   

10.
Summary Non-ionic surfactants showed minor effects on the uptake of H3-palmitic acid into the lipids of rat pancreasin vitro. In the presence of the cationic and anionic surfactants tested, the fraction of free H3-palmitic acid bound by the tissue increased. Only the anionic laurylsulfate, however, stimulated the uptake of H3-palmitic acid into neutral lipids without stimulating its uptake into phospholipids.   相似文献   

11.
Summary After administration of various C2-compounds as well as leucine-2-14C toCatharanthus roseus shoots and glycine-2-14C toStrychnos nux vomica plants no specific incorporation into the non-tryptophan C9–10 moiety of indole alkaloids was observed. The results indicate that glycine-2-14C is transformed into serine and is incorporated via tryptophan into strychnine.  相似文献   

12.
Summary The incorporation of leucice-14C into protein in bovine mesenteric arteries was augmented by cyclic GMP (10–3 M) and decreased by cyclic AMP (10–3 M). There was no effect of 5 AMP (10–3 M). The phosphodiesterase inhibiting drugs theophylline (10–3 M) and papaverine (5×10–5 g/ml) both decreased the leucine-14C incorporation.We are indebted to Mrs.Lena Burlin for hear assistance. Finacial support has been provided by the Swedish State Medical Research Council (No. 04X-101X-4498).  相似文献   

13.
(6R*)-{(2S*)-2-hydroxyheneicos-12-enyl}-5,6-dihydro-2H-pyran-2-one (1)o is the major constituent of the secretion of freshly dissected Dufour's gland of the urticating antTetramorium aculeatum. In solution, compound 1 is slowly transformed into (1S*, 5R*, 7S*)-7-(nonadec-10-enyl)-2,6-dioxabicyclo[3.3.1]nonan-3-one (2)o on standing. The structures of compounds 1 and 2 have been established on the basis of their spectral and chemical properties. Compound 1 could be responsible for the urticating properties of the ant.o IUPAC numbering.  相似文献   

14.
Summary The Noetherian surfaceF 4 (3) , which is represented on a plane by a linear 3 system ofC 9(A 1 3 A 2 3 A 3 3 A 4 3 A 5 3 A 6 3 A 7 3 A 8 3 A 9 2 A 10), possesses generally only one linear pencil of elliptic cubics. IfA i (i=1, 2, , 9) are the basis points of aHalphen pencil ofC 9,A 10 is infinitely near toA 9, and in this caseF 4 (3) is a not trivial example of such a surface with two pencils of elliptic cubics.  相似文献   

15.
Summary DCP increases IAA destruction by bothLens andPhaseolus root breis. H2O2 inhibits catabolism byLens extracts but activates it whenPhaseolus is used, mainly when roots are cultivated in the dark and contain inhibitors of IAA destruction. DCP 1·10–3 M and H2O2 1·10–4 or 1·10–3 volume forLens and DCP 1·10–4 M and H2O2 1·10–3 volume forPhaseolus nullify auxin catabolism.  相似文献   

16.
Allometry of mammalian cellular oxygen consumption   总被引:3,自引:0,他引:3  
In the 1930s, Max Kleiber and Samuel Brody established that the interspecies correlation between mammalian body mass and metabolic rate (αM0.75) cannot be explained (solely) by whole body surface area (αM0.66) to volume ratios. Metabolic considerations must also be taken into account. Decreases in the proportion of visceral organ mass to whole body mass can account for some of the whole body metabolic differences. However, superimposed upon these anatomical differences, the metabolism of tissues and cells has been demonstrated to decrease with increasing body mass. These decreases in oxygen consumption rates (with increasing body mass) in cells and tissues can be explained by a decrease in ATP turnover and mitochondrial density and an increase in mitochondrial functional efficiency (decrease in proton leak). The majority of the proton leak differences reflect differences in mitochondrial inner membrane surface area. Indeed, liver metabolism correlates directly with liver mitochondrial inner membrane surface area. Apart from being a significant contributor (~25 %) to basal metabolism, mitochondrial proton leak is a major factor determining the differences in basal metabolism between mammals of different body mass. Received 31 May 2000; received after revision 2 October 2000; accepted 14 November 2000  相似文献   

17.
Summary Five hybridomas secreting monoclonal antibody toE. coli L-asparaginase were isolated. These monoclonal antibodies were classified into 3 different subclasses; Ig G1 (1 clone), Ig G2 (2 clones) and Ig G3 (2 clones). One of them possessed anti-L-asparaginase neutralizing activity. Four antibodies examined demonstrated a linear Langmuir binding plot and binding affinities, with equilibrium dissociation constant (Kd) ranging between 2.5×10–9M and 6.3×10–10 M. The monoclonal antibodies should be useful probes for investigation of the enzyme activity.  相似文献   

18.
Summary The absorption of3H-digitoxin from perfused rat small intestine was inhibited by probenecid (1.0×10–2 M), ethacrynic acid (0.5×10–3 M), and mersalyl (8.0×10–3 M) indicating that digitoxin absorption is at least partly an active process.  相似文献   

19.
Summary In brain1, heart2 and kidney3, cell work in the absence of oxygen has been thought to precipitate anoxic damage by increasing the rate of depletion of cellular energy stores. In the medullary thick ascending limb of isolated perfused rat kidneys, however, reduction of ATP synthesis by a variety of mitochondrial or metabolic inhibitors caused ATP depletion comparable to that produced by oxygen deprivation but did not reproduce the lesions of anoxia. In these cells, unrestrained mitochondrial activity may be an important source of anoxic injury.  相似文献   

20.
To understand the role of calcium ions in thigmotaxis inParamecium caudatum, the effects of caffeine, ruthenium red and lanthanum (LaCl3) on thigmotaxis were examined. Thigmotaxis in the CNR mutant, which lacks voltage-dependent Ca2+-channels in the ciliary membrane, was also examined. Ruthenium red and LaCl3 suppressed thigmotaxis inP. caudatum, while caffeine enhanced it. The CNR mutant showed hardly any thigmotaxis. It can be thought that an increase in Ca2+ influx and the intraciliary concentration of Ca2+ ions induces thigmotaxis inParamecium.  相似文献   

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