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排序方式: 共有191条查询结果,搜索用时 125 毫秒
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The present experiments were performed in order to analyze whether the administration of estrogens (single injection of 500 micrograms of estradiol benzoate s.c.) to neonatal male rats might modify the weight of the ventral prostate and the epididymis as well as the metabolism of testosterone in these two organs. The metabolism of testosterone was evaluated in vitro using 14C-radiolabelled testosterone as the substrate. The metabolites dihydrotestosterone (DHT), 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-diol), 5 alpha-androstane-3 beta,17 beta-diol (3 beta-diol), androstenedione, 5 alpha-androstane-3,17-dione (5-A-dione) and 3 alpha-hydroxy-5 alpha-androstane-17-one (androsterone) were quantified. After neonatal estrogen administration animals were killed on days 22 and 90 of age. The following changes were observed: (1) the body weight, the weight of the testes and of the ventral prostate were lower than in controls on both day 22 and 90; (2) the weight of the epididymides was higher than in controls on day 22 and lower on day 90; (3) in the ventral prostate the in vitro formation of DHT was lower and that of the diols was higher than in control tissue on day 22 of age; (4) the in vitro formation of alpha-reduced metabolites of the 17-keto series (5 alpha-A-dione + androsterone) was higher in ventral prostate of treated animals than in that of controls on day 22; (5) in treated animals, no formation of DHT in the caput epididymis was observed at day 22. On the contrary, at the same age the formation of androstenedione was higher than in controls; on day 90 of age the formation of DHT, androstenedione and the 5 alpha-reduced metabolites of the 17-keto series was identical in caput epididymis of the treated animals and of the controls, while the formation of the diols was higher in the treated than in the controls. The data indicate that neonatal estrogenization may induce important changes in testosterone metabolism in the prostates and in the epididymides of the rat. 相似文献
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An Ustilago maydis ergosterol biosynthesis mutant (A14) which is partially blocked in sterol 14alpha-demethylase (P45014DM) activity is described. This mutant accumulated the abnormal 14alpha-methyl sterols, eburicol, 14alpha-methylfecosterol, and obtusifoliol, along with significant amounts of ergosterol. Although the A14 mutant grew nearly as well as the wild type, it was impaired in cell extension growth, which indicated a dysfunction in apical cell wall synthesis. The mutant was also found to be hypersensitive to the azole fungicides penconazole and tebuconazole. 相似文献
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Nicola Chiarelli Nicoletta Zoppi Marco Ritelli Marina Venturini Daniele Capitanio Cecilia Gelfi Marina Colombi 《生物化学与生物物理学报:疾病的分子基础》2021,1867(4):166051
Hypermobile Ehlers-Danlos syndrome (hEDS), mainly characterized by generalized joint hypermobility and its complications, minor skin changes, and apparently segregating with an autosomal dominant pattern, is still without a known molecular basis. Hence, its diagnosis is only clinical based on a strict set of criteria defined in the revised EDS nosology. Moreover, the hEDS phenotypic spectrum is wide-ranging and comprises multiple associated signs and symptoms shared with other heritable or acquired connective tissue disorders and chronic inflammatory diseases. In this complex scenario, we previously demonstrated that hEDS patients' skin fibroblasts show phenotypic features of myofibroblasts, widespread extracellular matrix (ECM) disarray, perturbation of ECM-cell contacts, and dysregulated expression of genes involved in connective tissue architecture and related to inflammatory and pain responses. Herein, the cellular proteome of 6 hEDS dermal myofibroblasts was compared to that of 12 control fibroblasts to deepen the knowledge on mechanisms involved in the disease pathogenesis. Qualitative and quantitative differences were assessed based on top-down and bottom-up approaches and some differentially expressed proteins were proofed by biochemical analyses. Proteomics disclosed the differential expression of proteins principally implicated in cytoskeleton organization, energy metabolism and redox balance, proteostasis, and intracellular trafficking. Our findings offer a comprehensive view of dysregulated protein networks and related pathways likely associated with the hEDS pathophysiology. The present results can be regarded as a starting point for future in-depth investigations aimed to decipher the functional impact of potential bioactive molecules for the development of targeted management and therapies. 相似文献
6.
JA Kiernan 《Biotechnic & histochemistry》2013,88(5-6):203-210
Hexazonium pararosaniline is a valuable reagent that has been used in enzyme activity histochemistry for 50 years. It is an aqueous solution containing the tris-diazonium ion derived from pararosaniline, an aminotriarylmethane dye, and it contains an excess of nitrous acid that was not consumed in the diazotization reaction. Other investigators have found that immersion for 2 min in an acidic (pH 3.5) 0.0015 M hexazonium pararosaniline solution can protect cryostat sections of unfixed animal tissues from the deleterious effects of aqueous reagents such as buffered solutions used in immunohistochemistry, while preserving specific affinities for antibodies. In the present investigation hexazonium pararosaniline protected lymphoid tissue and striated muscle against the damaging effects of water or saline. The same protection was conferred on unfixed sections treated with dilute nitrous or hydrochloric acid in concentrations similar to those in hexazonium pararosaniline solutions. Model tissues (solutions, gels or films containing gelatin and/or bovine albumin) responded predictably to well known cross-linking (formaldehyde) or coagulant (mercuric chloride) fixatives. Hexazonium pararosaniline solutions prevented the dissolution of protein gels in water only after 9 or more days of contact, during which time considerable swelling occurred. It is concluded that there is no evidence for a “fixative” action of hexazonium pararosaniline. The protective effect on frozen sections of unfixed tissue is attributable probably to the low pH of the solution. 相似文献
7.
Water hyacinth Eichhornia crassipes is considered the most damaging aquatic weed in the world. However, few studies have quantified the impact of this weed economically and ecologically, and even fewer studies have quantified the benefits of its control. This paper focuses on water loss saving as the benefit derived from biological control of this plant between 1990 and 2013 at New Year’s Dam, Alicedale, Eastern Cape, South Africa. Estimates of water loss due to evapotranspiration from water hyacinth vary significantly; therefore, the study used three different rates, high, medium and low. A conservative raw agriculture value of R 0.26 per m3 was used to calculate the benefits derived by the water saved. The present benefit and cost values were determined using 10% and 5% discount rates. The benefit/cost ratio at the low evapotranspiration rate was less than one, implying that biological control was not economically viable but, at the higher evapotranspiration rates, the return justified the costs of biological control. However, at the marginal value product of water, the inclusion of the costs of damage to infrastructure, or the adverse effects of water hyacinth on biodiversity, would justify the use of biological control, even at the low transpiration rate. 相似文献
8.
The Tau/A152T mutation,a risk factor for frontotemporal‐spectrum disorders,leads to NR2B receptor‐mediated excitotoxicity
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Astrid Sydow Frank JA Dennissen Zuzana Siskova Eckhard Mandelkow Eva‐Maria Mandelkow 《EMBO reports》2016,17(4):552-569
We report on a novel transgenic mouse model expressing human full‐length Tau with the Tau mutation A152T (hTauAT), a risk factor for FTD‐spectrum disorders including PSP and CBD. Brain neurons reveal pathological Tau conformation, hyperphosphorylation, mis‐sorting, aggregation, neuronal degeneration, and progressive loss, most prominently in area CA3 of the hippocampus. The mossy fiber pathway shows enhanced basal synaptic transmission without changes in short‐ or long‐term plasticity. In organotypic hippocampal slices, extracellular glutamate increases early above control levels, followed by a rise in neurotoxicity. These changes are normalized by inhibiting neurotransmitter release or by blocking voltage‐gated sodium channels. CA3 neurons show elevated intracellular calcium during rest and after activity induction which is sensitive to NR2B antagonizing drugs, demonstrating a pivotal role of extrasynaptic NMDA receptors. Slices show pronounced epileptiform activity and axonal sprouting of mossy fibers. Excitotoxic neuronal death is ameliorated by ceftriaxone, which stimulates astrocytic glutamate uptake via the transporter EAAT2/GLT1. In summary, hTauAT causes excitotoxicity mediated by NR2B‐containing NMDA receptors due to enhanced extracellular glutamate. 相似文献
9.
Hernandez-Trejo A B Estrada-Drouaillet JA López-Santillán C Rios-Velasco SE Varela-Fuentes R Rodríguez-Herrera E Osorio-Hernández 《Phyton》2019,88(1):47-54
The control of Spodoptera frugiperda is based
on synthetic insecticides, so some alternatives are the use of
entomopathogenic fungi (EF) and neem extract. The objective of
the study was to evaluate in vitro effectiveness of native EF and
neem extracts on S. frugiperda larvae. Six EF were identified by
DNA sequencing of ITS regions from three EF (Fusarium solani,
Metarrhizium robertsii, Nigrospora spherica and Penicillium
citrinum). They were evaluated in concentrations of 1 × 10⁸ spores/
mL. In addition, a second bioassay was carried out evaluating
only F. solani, M. robertsii and N. sphaerica and the addition
of vegetable oil. On the other hand, extraction of secondary
metabolites from neem seed (Azadirachta indica) was carried
out by performing, mass (g) and solvent volume (mL ethanol
and water) combinations, which were subjected to microwaves
and ultrasound. Subsequently, these extracts were evaluated
in concentrations of 3%, 4% and 5%. A survival analysis was
performed for each of the bioassays. With respect to the results
of the first bioassay, F. solani obtained a probability of survival of
0.476 on the seventh day, while in the second bioassay, M. robertsii
obtained 0.488 survival probability. This suggests that the expected
percentage of larvae that stay alive on the sixth day is 48.8%.
However, in the evaluation of the neem extract the combination
1:12/70% to 4% caused 84% mortality of larvae. The use of native
HE and neem extracts has potential for the control of S. frugiperda. 相似文献
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