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31.
F González Echeverría P S Cuasnicú A Piazza L Pi?eiro J A Blaquier 《Journal of reproduction and fertility》1984,71(2):433-437
The fertility of spermatozoa from the different epididymal segments of hamsters was tested by in-vivo insemination. Caput and proximal corpus spermatozoa were non-fertile; spermatozoa from the distal corpus epididymidis fertilized 13% (38/290) oocytes and those from the proximal and distal cauda epididymidis 71 and 87%, respectively. When tested by in-vitro insemination, distal corpus spermatozoa penetrated 44% of oocytes while those from the distal cauda fertilized 87% of oocytes. Spermatozoa from the distal corpus recovered in Medium BMOC fertilized 13% (28/219) of oocytes in vivo, while those mixed with an epididymal protein preparation (0.8 mg protein/ml) fertilized 24% (49/204; P less than 0.01) of oocytes. When distal corpus spermatozoa were inseminated in vivo with 0.8 mg epididymal protein preparation 34% (31/90) oocytes were fertilized and only 22% (23/103; P less than 0.05) oocytes were fertilized when the proteins were obtained from epididymides of animals castrated for 30 days. When distal corpus spermatozoa were preincubated for 5 h in medium without (control) or with protein preparation (0.8 or 1.6 mg protein/ml), a significant increase in in-vitro oocyte penetration was found (25 compared with 45%; P less than 0.05) when the protein was present at 1.6 mg/ml. These results confirm and extend previous observations suggesting a role for androgen-dependent glycoproteins secreted by the epididymis in the acquisition of fertilizing ability that occurs during sperm maturation. 相似文献
32.
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34.
Júlia Cabrita 《Mycopathologia》1974,54(3):347-360
A critical survey is made of human mycoses diagnosed in European Portugal and in the Portuguese Overseas Provinces. Dermatophyte infections and pityriasis versicolor are commom in the entire territory. The more frequently isolated dermatophytes in Continental Portugal wereTrichophyton violaceum, Microsporum canis, Trichophyton tonsurans andTrichophyton schoenleinii, in the scalp andTrichophyton rubrum, Trichophyton mentagrophytes, Trichophyton megninii andEpidermophyton floccosum in the other body sites. In the Overseas Provinces the species found in white people were very much the same, whereas in negroes mainlyMicrosporum audouinii andT. violaceum in Mozambique,M. audouinii in Angola, andTrichophyton soudanense, M. audouinii andT. rubrum in Guinea were identified.In Continental Portugal cases of candidiasis, mycetoma, aspergillosis, sporotrichosis and cryptococcosis were described in patients who had never been outside Europe; and tinea nigra, African histoplasmosis and South-American blastomycosis in individuals who live or lived in India, Africa and Brazil.The first case of North-American blastomycosis was reported in Mozambique. 相似文献
35.
A Alvarez U Hidalgo M E Kawada A Munizaga A Zú?iga L Ibánez C S Koenig M J Santos 《Analytical biochemistry》1992,206(1):147-154
This paper shows the successful isolation of peroxisomes from human liver samples that were kept frozen at -70 degrees C. Purification of these peroxisomes was obtained by a combination of two subcellular fractionation techniques: differential centrifugation and isopycnic fractionation in Nycodenz density gradients. Peroxisome integrity was evaluated by latency measurements and by ultrastructural observation. The procedure described here may be useful for the isolation of other subcellular organelles from frozen human samples. 相似文献
36.
B Teutsch C Bihoreaú C Monnot K E Bernstein T J Murphy R W Alexander P Corvol E Clauser 《Biochemical and biophysical research communications》1992,187(3):1381-1388
A rat vascular AT1 receptor cDNA has been stably expressed into Chinese Hamster Ovary cells and the resulting recombinant AT1a receptor has been functionally characterized. This receptor binds 125I Sar1-angiotensin II with an affinity of 0.9 nM and the displacement of this ligand by a series of peptidic and nonpeptidic analogs is shown. Binding of angiotensin II to this receptor causes a rapid increase in inositol phosphate production, whereas this effect is not observed in nontransfected cells. Des-aspartyl1 angiotensin II and at a lesser extent angiotensin I are also able to produce an increase in inositol phosphates. More importantly, the actions of angiotensin II on cell division were clearly demonstrated in this model, since angiotensin II is able to stimulate DNA synthesis by 400% and double the cell population of the transfected cells in 36 hours in the absence of any other growth factor, whereas no effect is observed in nontransfected cells. 相似文献
37.
Francisco Guillén Angel T. Martinez Maria Jesús Martínez 《Applied microbiology and biotechnology》1990,32(4):465-469
Summary Production of extracellular hydrogen peroxide by fungal oxidases is been investigated as a requirement for lignin degradation. Aryl-alcohol oxidase activity is described in extracellular liquid and mycelium ofPleurotus eryngii and studied under non-limiting nitrogen conditions. This aryl-alcohol oxidase catalyses conversion of primary aromatic alcohols to the corresponding aldehydes and H2O2, showing no activity with aliphatic and secondary aromatic alcohols. The enzyme is stable at pH 4.0–9.0, has maximal activity at 45°–50°C and pH 6.0–6.5, is inhibited by Ag+, Pb2+ and NaN3, and has aK
m
of 1.2 mM using veratryl alcohol as substrate. A single protein band with aryl-alcohol oxidase activity was found in zymograms of extracellular and intracellular crude enzyme preparations fromP. eryngii. 相似文献
38.
Palmaria decipiens, one of the most abundant red seaweeds of the chilean Antarctic, was collected in King George Island. The hot water extract (26% yield) showed by acid hydrolysis to contain xylose, galactose and traces of glucose. Fractionation with cetrimide gave a soluble neutral xylan and an insoluble fraction. The insoluble fraction afforded an acidic polysaccharide that contained 4.8% of uronic acids, 2.8% of sulfate and 18.9% of protein. Polyacrylamide gel electrophoresis showed that it was homogeneous. The GLC and HPLC analysis of the total acidic hydrolysis products showed that the acidic polysaccharide was composed of the neutral sugars galactose and xylose in the molar ratio 8.2:1.0 and of galacturonic and glucuronic acid in the ratio 1.5:1.0. The second-derivative FT-IR spectrum showed the characteristic amide I, II and III bands of proteins. Alkaline cleavage with 0.1 M NaOH indicated the presence of a glycoprotein with O-glycosidic linkage.Results found in this work suggest that the acidic polysaccharide extracted from Palmaria decipiens is an acidic xylogalactan-protein complex. 相似文献
39.
Jesús Arellano Filiberto Vázquez Thelma Villegas Georgina Hernández 《Plant cell reports》1996,15(7):455-458
Summary The sesquiterpene quinone currently known as perezone is abundantly produced by the roots of Perezia cuernavacana. This compound is of biotechnological interest since it may be used as a pigment and has several pharmacological properties. In this work we demonstrate that perezone is also produced in transformed root cultures of P. cuernavacana. Hairy roots were induced by inoculation of internodal segments of sterile plants of P. cuernavacana with Agrobacterium rhizogenes AR12 strain. The axenic liquid MS medium cultures of the hairy roots isolated from the internodes showed active growth in the absence of growth regulators. The transformed nature of the tissue was confirmed by genomic integration (PCR and slot blot hybridization) and expression (enzyme activity) of the marker gus-gene. The production of perezone by a transformed root culture was evidenced by IR spectroscopy. Our results offer an alternative for enhanced production of perezone and represent an advantage over its extraction from natural plant populations which present problems in their agronomic culture. 相似文献
40.
Jose-Emilio Mesonero María-Carmen Rodríguez Yoldi María-Jesús Rodríguez Yoldi 《Biological trace element research》1996,51(2):149-159
The element Cd is considered to have no biological function and is highly toxic to humans and animals. Toxic effects of this
metal upon cell membrane structure and function have been shown. On the other hand, Ca is an essential element in a wide variety
of cellular activities. The present study was initiated to research whether the interaction between Ca and Cd could affect
D-galactose absorption across the rabbit jejunum in vitro. In media with Ca2+, when CdCl2 was present at 0.5 or 1 mM, Cd was found to significantly reduce the sugar absorption. In Ca2+-free media, where CaCl2, was omitted and replaced isotonically with choline chloride, the sugar transport was not modified by Cd, but when CaCl2 was replaced isotonically with MgCl2, the inhibition is observed. Verapamil at 10−6
M (blocking mainly Ca2+ transport) did not modify the inhibitory effect of cadmium on D-galactose transport. When 10−6
M of A 23187 (Ca2+ specific ionophore) was added in media with/without Ca2+; CdCl2 produced no change in D-galactose transport. These results suggest that Ca and Cd could have affinity for the same chemical
groups of enterocyte membrane, which would be related with the intestinal absorption of D-galactose. 相似文献