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931.
Nuclear fractions isolated from Amanita phalloides, Amanita muscaria and Agaricus bisporus were subjected to in vitro RNA synthesis assays in the presence of various concentrations of amatoxins. The mushroom nuclei were highly insensitive to inhibition by amatoxin when compared to assays of nuclear fractions isolated from the Oömycete fungus, Achlya ambisexualis and from rabbit brain.Abbreviations DTT
dithiothreitol
- PMSF
phenylmethyl sulfonyl fluoride
- MES
2[N-morpholino] ethane sulfonic acid
Paper no. 1-78 相似文献
932.
Paul A. Friedman Edward G. Platzer 《Biochimica et Biophysica Acta (BBA)/General Subjects》1978,544(3):605-614
The binding and inhibitory properties of 11 benzimidazoles for bovine brain tubulin were investigated. The effects of the benzimidazoles on the initial rates of microtubule polymerization were determined by a turbidimetric assay. The median inhibitory concentrations (I50) for nocodazole, oxibendazole, parbendazole, mebendazole and fenbendazole ranged from 1.97 · 10−6 to 6.32 · 10−6 M. Benomyl, cambendazole and carbendazim had I50 values from 5.83 · 10−5 to 9.01 · 10−5 M. Thiabendazole had an I50 value of 5.49 · 10−4 M. Inhibitor constants (Ki) were determined by the colchicine binding assay. Oxibendazole, fenbendazole, and cambendazole had Ki values of 3.20 · 10−5, 1.73 · 10−5 and 1.10 · 10−4 M, respectively. Oxibendazole and fenbendazole were competitive inhibitors of colchicine. In contrast, cambendazole was a noncompetitive inhibitor of colchicine. The ability of these benzimidazoles to inhibit microtubule polymerization and the mode of action for the anthelmintic benzimidazoles is discussed. 相似文献
933.
Peter H. Byers Karen A. Holbrook Judith G. Hall Paul Bornstein John W. Chandler 《Human genetics》1978,40(2):157-169
Summary Several individuals from one family are described with a unique form of spondyloepiphyseal dysplasia. Characteristic features include shorttrunked short stature, punctate corneal dystrophy and marked disorganization of dermal collagen fibrils when examined by transmission electron microscopy. Inheritance is compatible with either dominance and a variable expression or X-linkage. Although the basic defect has not been determined, the tissue distribution is consistent with a defect in a non-collagenous component that affects collagen fibril formation or stability. 相似文献
934.
The fructose-1,6-P2 (FDP) phosphatase, (FDPase) and FDP aldolase fromPseudomonas putida were partially purified by a combination of (NH4)2SO4 fractionation and DEAE-Sephadex column chromatography. Michaelis-Menten kinetics were observed with, respect to FDP in both
FDPase and FDP aldolase. TheK
m
for FDP at pH 8.0 was 1.2×10−5M for FDPase and 3.0×10−5M for FDP aldolase. The specific activities of these two enzymes (assayed under optimal conditions in cell-free extracts ofP. putida grown ond-fructose), as well as their kinetic properties, are consistent with the suggestion that during growth ond-fructose most, of the FDP generated is converted to fructose-6-P (F-6-P), which is subsequently utilized via the Entner-Doudoroff
pathway (EDP). 相似文献
935.
Summary The ultrastructure of the thread-like hairs (sensilla) on the tibia of the front leg ofAcheta domesticus (Gryllidae) Saltatoria was examined by serial sectioning. The presence of a tubular body indicates that these sensilla are mechanosensitive; electrophysiological measurements also confirmed this. The opposing forces on the articulating apparatus of single hairs and the sensitivity of the single receptor cell were measured after deflection of the hair in different directions. The articulating apparatus is characterized by three cuticular elements: a joint membrane, suspension fibers, and a socket septum. These elements form the basis for a structural bilateral symmetry along whose plane of symmetry the direction line of both the minimum receptor sensitivity and the minimum opposing forces lie. The tubular body embedded in the tip of the socket septum is attached to the base of the hair shaft. The hair provides the leverage for displacing the tubular body and the socket septum limits the extent to which it may be laterally displaced.These investigations have been supported by the Deutsche Forschungsgemeinschaft 相似文献
936.
Paul N. Adler 《Development genes and evolution》1978,185(3):271-292
Summary Mutations of the bithorax complex result in segmental transformations in the thorax and abdomen ofDrosophila. The haltere discs from larvae homozygous forbx
3 orpbx are transformed so that the discs contain cells that will produce wing cuticle as well as cells that produce haltere cuticle. The pattern regulation behavior of these discs has been examined. The fate maps of the two discs were established, and then the regulative behavior of a number of fragments from both types of mutant discs was established by culturing the fragments in vivo prior to metamorphosis. The most important conclusion from this work is that the cells producing, haltere cuticle and wing cuticle within the same disc share the same positional information and that they communicate during pattern regulation. 相似文献
937.
A phytoplankton investigation was carried out in the subalpine, low-productive Norwegian lake Øvre Heimdalsvatn in 1969–70 and 1972. This paper describes the temporal and spatial distribution of the standing stock of phytoplankton, and phytoplankton primary productivity. The annual average primary productivity in 1972 was 4.0–4.9 mg C m−3 d−1 ; the annual average standing stock varied from 120 mg m−3 (freshweight) in 1969–70, to 250 mg m−3 in 1972. Phytoplankton species composition and size distribution is discussed. Throughout the year the phytoplankton is dominated by small (ultraplankton) species; μ-algae (< 5 μm) showed cell concentrations up to 15 mill. cells 1−1 . The dominating group was chrysophytes; cryptophytes, dinoflagellates or green algae were at times abundant. A phytoplankton monthly budget and a diagram showing annual average carbon flow through the standing stock of phytoplankton are presented; the phytoplankton dynamics in Øvre Heimdalsvatn is compared to that of other low-productive lakes. 相似文献
938.
Samples of drifting and periphytic microalgae were collected during 1972 from a fast-flowing, stony stream (Brurskardsbekken) in the Jotunheimen mountain area, central southern Norway. The predominant algal groups in the drift and the periphyton were diatoms and green algae, while only a few species were recorded in both communities. A considerable number of species from Chrysophyceae, Cryptophyceae and other algal classes were also recorded in the drift samples. The species composition was in good agreement with microalgal communities earlier described from mountain areas in Scandinavia, although species which probably are new to Norway, were also recorded. A quantitatively important fraction of planktonic species in the drift is interpreted as a contribution from lacustrine habitats in the watercourse. A general change in the periphyton during the summer, from green algae to diatoms, was observed, Altitudinal differences in the periphyton included a delayed green algal maximum at higher altitudes compared to lower. In the zone around the upper birch limit, a transition in species composition as one goes up stream, described in other investigations, was not observed. 相似文献
939.
J H Iser Paul N Maton Gerard M Murphy R Hermon Dowling 《BMJ (Clinical research ed.)》1978,1(6126):1509-1512
In most patients with radiolucent gall stones who were given chenodeoxycholic acid (CDCA) in doses of 13-15 mg/kg body weight/day the bile became unsaturated in cholesterol, and their gall stones dissolved. The patients whose stones did not dissolve were significantly heavier and fatter than the responders, which suggested that obese patients might be “resistant” to the effects of CDCA. To test this hypothesis, 32 consecutive patients presenting for medical treatment of gall stones had their ideal body weight (IBW) and estimated body fat mass calculated. The eight most obese and the eight least obese patients were then selected, and their fasting bile lipid responses to CDCA 13-15 mg/kg/day were measured. The very obese patients were also given larger doses, and any changes in bile lipid composition were studied in relation to subsequent gall-stone dissolution.Before treatment the obese patients had a higher mean biliary cholesterol saturation index than the non-obese patients, and this difference was maintained during treatment with the normal dose of CDCA: the bile in the obese patients remained supersaturated while that in the non-obese became unsaturated with cholesterol. When the obese patients were given larger doses of CDCA their bile ultimately became unsaturated in cholesterol. Gall stones dissolved partially or completely in five of the eight non-obese patients after 6-18 months of 13-15 mg CDCA/kg/day, but none of the obese patients showed any response after comparable periods of treatment with this standard dose. With increased doses and unsaturated bile, however, three of the obese patients showed partial gall-stone dissolution after 3-12 months'' treatment and one showed complete gall-stone dissolution after three years'' treatment.These results suggest that when giving CDCA to patients with gall stones, larger than normal doses (some 18-20 mg/kg/day) should be prescribed. Alternatively the lipid composition of the patients'' bile should be monitored by duodenal intubation and the CDCA dose increased until the bile becomes unsaturated in cholesterol. 相似文献
940.
K.C. Nicolaou W.E. Barnette R.L. Magolda Paul A. Grieco W. Owens C.-L.J. Wang J.B. Smith M. Ogletree A.M. Lefer 《Prostaglandins & other lipid mediators》1978,16(5):789-794
The synthesis of the sodium salts of enantiomerically pure 12-fluoroPGI2 (9), (±)-12-fluoroPGI2 (9), (±)-15-epi-12-fluoroPGI2 (10), (±)-12-fluoro-13,14-dihydroPGI2 (11), (±)-12-fluoro-4(E)-isoPGI2 (12), and (±)-5,6-dihydro-12-fluoroPGI2 (13) is detailed starting from the corresponding derivatives of 12-fluoroPGF2α methyl ester. Prostacyclins 9, (±)-9, (±)-10, (±)-11, (±)-12, and (±)-13 have been evaluated for their ability to inhibit human platelet aggregation and their effect on smooth muscle (isolated cat coronary artery). 相似文献