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71.
We have shown that tellurite and tellurate require the interaction with reduced glutathione (GSH) to hemolyze human erythrocytes.
The study of the nature of this interaction is the main object of this paper. The degree of hemolysis was determined by the
method of Angelone. The addition of extracellular 1 mM GSH or cysteine increased the rate of hemolysis. Concanavalin A (0.3
mg/mL) and/or 4 mg/mL adenosine did not affect the hemolysis by 0.1 mM tellurite. One tenth to 1 mM 4-acetamido-4′-isothiocyanostilbene-2,2′-disulfonate
(SITS) inhibited this hemolysis by 60–100%. Millimolar GSH released this inhibition. Incubation of 0.1 mM tellurite with 1
mM GSH for 90 min at 37°C, produced a hemolytic agent when prepared and tested under nitrogen, but one that was not active
when prepared in air. The hemolysis byp-hydroxymercuribenzoate orp-hydroxymercuriphenylsulfonate did not involve GSH. Scanning electron micrographs showed a sphero-echinocyte transformation,
in the pre-hemolytic stage, with all the agents tested. The rate of penetration of tellurite plays a role in determining the
rate of hemolysis, as shown by the effect of SITS. The release by GSH of the inhibition by SITS poses questions concerning
the site of action and cell membrane penetration of the hemolytic agent. Telluride or some intermediate in the interaction
of GSH with tellurite is the actual hemolytic agent. 相似文献
72.
Dr. Marino Bortolussi Giulia Marini Maria Luisa Reolon 《Cell and tissue research》1979,197(2):213-226
Summary Changes in the distribution of the in vitro uptake of 125I-HCG by the ovaries of adult rats were examined histochemically throughout the estrous cycle.Only in follicles wider than 500 m, occurring mainly at diestrus and proestrus, could granulosa cells bind the labelled hormone. The labelling increased with follicular size and decreased in intensity from the peripheral granulosa cells inwards. No uptake occurred in the oocytes, in the cells of the cumulus oophorus nor in the granulosa cells of the atretic follicles.The binding capacity of the newly-formed corpora lutea of estrus was less than that of preovulatory follicles. The uptake of 125I-HCG by corpora lutea during the first cycle reached its maximum at diestrus but fell sharply by proestrus. The uptake was patchy in the corpora lutea of the second cycle and not significant in the older ones.The uptake of 125I-HCG by thecae increased with follicular size and was greater in the thecae of atretic follicles than in the thecae of growing follicles of like size. There was a greater uptake in the last formed interstitial tissue than there was in older tissue.At proestrus, the uptake of 125I-HCG was unaffected by the LH surge at 18.00h but had decreased slightly at 24.00 h.The implications of these data in relation to the regulation of receptor sites, is discussed. 相似文献
73.
The manner in which centromere regions of mitotic chromosomes are distributed with respect to the age of their DNA was studied. Cells of the Indian deer, Muntiacus muntjak, were grown in the presence of bromodeoxyuridine (BrdU) for two generations and stained with the fluorescent dye Hoechst 33258. Chromatids containing granddaughter DNA appear dim when compared with those containing grandparental DNA. The frequencies of the various anaphase patterns of bright and dim centromere regions were binomially distributed, indicating random distribution of chromatids with respect to the age of their DNA templates. 相似文献
74.
Biosynthesis of saturated and unsaturated fatty acids by a T-strain mycoplasma (Ureaplasma). 总被引:4,自引:3,他引:1
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A human T mycoplasma (Ureaplasma urealyticum) incorporated radioactivity into its lipids from [1-14C]acetate in the growth medium. Methanolysis of the lipids showed the label to be confined almost entirely to the methyl esters of the fatty acids. About 80% of the label was associated with the methyl esters of the saturated fatty acids, and the rest was found in the unsaturated methyl ester fraction. Gas-liquid chromatography of the saturated methyl esters showed the label to be present in the peaks of palmitate, myristate, and stearate, whereas in the unsaturated methyl ester fraction most of the radioactivity emerged in the peak of palmitoleate. The addition of either oleic or palmitic acid to the growth medium markedly decreased the organisms' incorporation of radioactivity from acetate. It is concluded that the T mycoplasma strain is capable of de novo synthesis of both saturated and unsaturated fatty acids, in this respect differing from all of the Mycoplasma and Acholeplasma strains investigated to date. 相似文献
75.
Franco Bellesia Romano Grandi Alessandro Marchesini Ugo M. Pagnoni Roberto Trave 《Phytochemistry》1975,14(8):1737-1740
Ageratriol is biosynthesized from agerol through a diepoxide derivative. Mevalonic acid incorporation revealed that the formation of the isopropenylic double bond is not stereospecific. 相似文献
76.
77.
Anna Andreozzi Pilar Prieto Jesús Mercado-Blanco Stefano Monaco Elisa Zampieri Silvia Romano Gianpiero Valè Roberto Defez Carmen Bianco 《Environmental microbiology》2019,21(9):3489-3504
Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, 1-aminocyclopropane-1-carboxylate deaminase activity and production of siderophores and phytohormones, can be assessed as plant growth promotion traits. Our aim was to evaluate the effects of nitrogen fixing and indole-3-acetic acid (IAA) producing endophytes in two Oryza sativa cultivars (Baldo and Vialone Nano). Three bacteria, Herbaspirillum huttiense RCA24, Enterobacter asburiae RCA23 and Staphylococcus sp. 377, producing different IAA levels, were tested for their ability to enhance nifH gene expression and nitrogenase activity in Enterobacter cloacae RCA25. Results showed that H. huttiense RCA24 performed best. Improvement in nitrogen fixation and changes in physiological parameters such as chlorophyll, nitrogen content and shoot dry weight were observed for plants co-inoculated with strains RCA25 and RCA24 in a 10:1 ratio. Based on confocal laser scanning microscopy analysis, strain RCA24 was the best colonizer of the root interior and the only IAA producer located in the same root niche occupied by RCA25 cells. This work shows that the choice of a bio-inoculum having the right composition is one of the key aspects to be considered for the inoculation of a specific host plant cultivar with microbial consortia. 相似文献
78.
79.
Abstract A study was made on the changes observed in the protein, starch and soluble sugar content during development of siliquas and seeds of rapeseed grown in central Italy. Concentration of starch and soluble sugars in the seed increases to 75 per cent dry matter during the first few weeks of pod development and then drops to minimum values. The protein increases steadily until maturity, when a level of 0.85 mg per seed is reached, equivalent to 18 per cent dry matter. The protein and starch in the hull? decrease continuously during development, while in the initial stages the soluble sugars are accumulated until they account for 33 per cent dry matter, after which they decline towards maturity. 相似文献