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61.
Hormonal control of uteroglobin secretion in rabbit uterus. Inhibition of uteroglobin synthesis and messenger ribonucleic acid accumulation by oestrogen and anti-oestrogen administration
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Helena T. Kopu Seija M. Hemminki Tuula K. Torkkeli Olli A. J?nne 《The Biochemical journal》1979,180(3):491-500
Investigations were conducted to quantify activity of uteroglobin mRNA and secretion of uteroglobin in rabbit uterus after administration of progesterone and 5alpha-dihydrotestosterone, either alone or concomitantly with oestradiol-17beta and tamoxifen, a non-steroidal anti-oestrogen. Poly(A)-containing mRNA was isolated from the uterine tissue by extraction with phenol/chloroform, precipitation with ethanol and chromatography on oligo(dT)-cellulose. Cell-free translation in vitro of the poly(A)-containing mRNA was carried out in a wheat-germ lysate, and the product isolated by specific immuno-precipitation with anti-uteroglobin antiserum purified by affinity chromatography. Radioimmunoassay was utilized to determine uteroglobin content in the uterine flushings and tissue preparations. When given for 5 days, both progesterone (1mg/kg per day) and 5alpha-dihydrotestosterone (25mg/kg per day) elicited a marked induction of uteroglobin secretion, which was accompanied with accumulation of uteroglobin mRNA in the tissue. Concomitant administration of oestradiol-17beta (50mug/kg per day) or tamoxifen (12.5mg/kg per day) significantly decreased both progesterone- and 5alpha-dihydrotestosterone-induced uteroglobin secretion, with a parallel decrease in the uteroglobin-mRNA activity. The decline in the uteroglobin content of the uterine flushes brought about by oestradiol-17beta or tamoxifen administration was not due to inhibition of secretion of this protein by the endometrial cells, since a simultaneous decrease occurred in the tissue uteroglobin content. After a 5-day pretreatment with progesterone (1mg/kg per day), administration of oestradiol-17beta (50mug/kg per day) during the ensuing 4 days greatly accelerated the decay of the uteroglobin content in the uterine fluid. 相似文献
62.
V.Ja. Brodsky T. L. Marshak V. Mareš Z. Lodin Z. Fülöp E. A. Lebedev 《Histochemistry and cell biology》1979,59(3):233-248
Summary A cytophotometric study of DNA content in Purkinje cells of the cerebellum of rats, cats, chicken and humans (Feulgen staining) revealed that in a certain number of cells the amount of DNA ranged between the diploid and tetraploid level (H2C cells). The incidence of H2C Purkinje cells varied among the species studied. In rats, which were studied most thoroughly, these cells amounted on average to 3%. In some rats, as well as in some cats and chickens H2C Purkinje cells were entirely absent. In the group of animals possesing H2C Purkinje cells, great interindividual differences were observed. In rats for instance, the incidence of these cells varied from 1 to 23 per cent. Topographic analyses carried out in rat and human cerebellum revealed that H2C Purkinje cells occurred more frequently in the hemispheres than in the vermis. No significant differences were found in the number of H2C Purkinje cells in healthy and Kilham-DNA-virus infected rats.Densitometric analysis of the distribution of nuclear chromatin showed that H2C Purkinje cells were richer in condensed chromatin, especially in the region of the nucleolus, which apparently contains the hyperploid surplus of DNA. It is proposed that the phenomenon of DNA hyperdiploidy arises as a result of either incomplete S-phase in some immature Purkinje cell precursors or the amplification of some DNA sequences particularly those localized in the nucleolar region. 相似文献
63.
Summary Intact and denervated extensor digitorum longus (EDL) muscles of 20-day-old inbred Lewis-Wistar rats were labelled with 3H-thymidine. Ninety minutes after the injection of the isotope 4.0% of the nuclei were labelled in the intact (i.e. innervated) and 9.6% in the muscles, denervated 3 days before administration of the isotope. The labelled EDL muscles were grafted into the bed of the previously removed EDL muscles of inbred animals and these isografts were studied 30 days later.In the EDL muscles, regenerated from innervated isografts only occasionally labelled endothelial cells were found whereas in the muscles regenerated from denervated isografts also parenchymal muscle nuclei were regularly labelled. The incidence of labelled nuclei in the regenerated EDL muscles was, however, about 20 times lower than in the donor EDL muscles. The present experiments provide a direct proof of utilization of donor satellite cell nuclei for regeneration in grafted muscle tissue. With respect to the low incidence of labelled nuclei in regenerated EDL muscles, other sources of cells apparently also contribute to the regeneration process. 相似文献
64.
The induction of − “petite” mutants by guanidine hydrochloride (GuHCl) is inhibited in several conditions. Anaerobiosis inhibited the induction either with or without cell multiplication. Both nalidixic acid (NA) and cycloheximide (CH) inhibited the induction of mutants. On the other hand, chloramphenicol (CAP) produced a dual effect: at low concentration it stimulated, at high concentration it inhibited, the induction. The effect of these different inhibitors on the transformation of + mother cells into − by GuHCl is discussed. 相似文献
65.
66.
Helena Santos-Rosa Gonzalo Millán-Zambrano Namshik Han Tommaso Leonardi Marie Klimontova Simona Nasiscionyte Luca Pandolfini Kostantinos Tzelepis Till Bartke Tony Kouzarides 《Molecular cell》2021,81(13):2793-2807.e8
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67.
Leonardo Mata Helena Gaspar Fátima Justino Rui Santos 《Journal of applied phycology》2011,23(5):827-832
The genus Asparagopsis is a prolific source of halogenated metabolites. Due to its commercial applications, it has been intensively cultivated in
southern Portugal. In the present study, we assess if the internal levels of the major halogenated metabolites (bromoform
and dibromoacetic acid) in Asparagopsis taxiformis can be increased with hydrogen peroxide (H2O2) addition. Previous studies with red algae showed that the production/release of bromoform can be enhanced by exogenously
supplying H2O2. However, no study has assessed if H2O2 supply enhances the content of secondary metabolites within the biomass. This detail is important as the objective of the
proposed research is to enhance the content of these valuable metabolites in the produced biomass. Both the activity of the
haloperoxidase enzyme and the metabolite content were assessed on short-term and long-term incubation periods to H2O2. To determine the susceptibility of A. taxiformis photosynthetic performance to the imposed oxidative stress, the in vivo fluorescence of photosystem II was monitored. A. taxiformis was shown to be physiologically vulnerable to H2O2, given the observed decrease of the maximum quantum yield of photosynthesis (F
v/F
m). Contrary to what was expected, the presence of H2O2 inhibited the activity of the iodoperoxidase enzyme. Nevertheless, the extracted halogenated metabolites were higher over
the first hours of exposure to H2O2, decreasing after 48 h. These results are probably related to the prosthetic group of the halogenated enzyme in A. taxiformis and the long-term oxidative stress damage of H2O2 exposure. Considering the objective of the proposed research, addition of H2O2 to the cultures, prior (3 h) to biomass harvesting, increases the metabolite content. 相似文献
68.
Beatriz Pereira Moreno Gislaine Cristiane Mantovanelli Letycia Lopes Ricardo Adriano Antnio Silva Rubem Silvrio De Oliveira Emy Luiza Ishii‐Iwamoto Maria Helena Sarragiotto Debora Cristina Baldoqui 《化学与生物多样性》2020,17(3)
Studies of the phytotoxic effects between plants can be a crucial tool in the discovery of innovative compounds with herbicide potential. In this sense, we can highlight ruzigrass (Urochloa ruziziensis), which is traditionally used in the crop rotation system in order to reduce weed emergence. The aim of this work was to characterize the secondary metabolites of ruzigrass and to evaluate its phytotoxic effects. In total, eight compounds were isolated: friedelin, oleanolic acid, α‐amyrin, 1‐dehydrodiosgenone, sitosterol and stigmasterol glycosides, tricin and p‐coumaric acid. Phytotoxic effects of the crude methanolic extract and fractions of ruzigrass were assessed using germination rate, initial seedling growth, and biomass of Bidens pilosa, Euphorbia heterophylla and Ipomoea grandifolia. Chemometric analysis discriminated the weed species into three groups, and B. pilosa was the most affected by fractions of ruzigrass. The phytotoxic activities of 1‐dehydrodiosgenone, tricin, and p‐coumaric acid are also reported, and p‐coumaric acid and 1‐dehydrodiosgenone were active against B. pilosa. 相似文献
69.
Josephine Joy Hubloher Sabine Zeidler Pedro Lamosa Helena Santos Beate Averhoff Volker Müller 《Environmental microbiology》2020,22(12):5156-5166
The stress protectant trehalose is synthesized in Acinetobacter baumannii from UPD-glucose and glucose-6-phosphase via the OtsA/OtsB pathway. Previous studies proved that deletion of otsB led to a decreased virulence, the inability to grow at 45°C and a slight reduction of growth at high salinities indicating that trehalose is the cause of these phenotypes. We have questioned this conclusion by producing ∆otsA and ∆otsBA mutants and studying their phenotypes. Only deletion of otsB, but not deletion of otsA or otsBA, led to growth impairments at high salt and high temperature. The intracellular concentrations of trehalose and trehalose-6-phosphate were measured by NMR or enzymatic assay. Interestingly, none of the mutants accumulated trehalose any more but the ∆otsB mutant with its defect in trehalose-6-phosphate phosphatase activity accumulated trehalose-6-phosphate. Moreover, expression of otsA in a ∆otsB background under conditions where trehalose synthesis is not induced led to growth inhibition and the accumulation of trehalose-6-phosphate. Our results demonstrate that trehalose-6-phosphate affects multiple physiological activities in A. baumannii ATCC 19606. 相似文献
70.
Gemma Aragonès Kalavathi Dasuri Opeoluwa Olukorede Sarah G. Francisco Carol Renneburg Caroline Kumsta Malene Hansen Shun Kageyama Masaaki Komatsu Sheldon Rowan Jonathan Volkin Michael Workman Wenxin Yang Paula Daza Diego Ruano Helena Dominguez‐Martín José Antonio Rodríguez‐Navarro Xue‐Liang Du Michael A. Brownlee Eloy Bejarano Allen Taylor 《Aging cell》2020,19(11)