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排序方式: 共有157条查询结果,搜索用时 15 毫秒
1.
Binding site selection analysis of protein-DNA interactions via solid phase sequencing of oligonucleotide mixtures. 总被引:3,自引:0,他引:3 下载免费PDF全文
By combining the concept of degenerate oligonucleotide mutagenesis (1,2,3,4) and the convenience of solid phase chemical DNA sequencing (5), we have developed a rapid procedure for determining the specificity of DNA-binding proteins in vitro. Starting with a degenerate oligonucleotide mixture, the technique assays for alternative nucleotides in fractions that are bound or non-bound to the protein of interest. In contrast to previous approaches using degenerate oligonucleotides, it does not involve cloning but rather employs direct sequencing of the oligonucleotide mixtures after attachment to a solid support. Solid state processing obviates the need for both DNA extractions from polyacrylamide gels and time-consuming ethanol precipitations. Because of its convenience and sensitivity, this binding site selection analysis is well suited to determining rapidly the sequence preference of DNA-binding proteins that are available in small amounts, and complements well established approaches like methylation interference or missing contact assays. The solid phase reaction protocol we propose can also improve these latter approaches. 相似文献
2.
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
3.
4.
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
5.
Rachel A. Hill Yee‐Wen Candace Wu Andrea Gogos Maarten van den Buuse 《Journal of neurochemistry》2013,126(3):389-399
Neurodevelopmental psychiatric disorders such as schizophrenia may be caused by a combination of gene × environment, gene × gene, and/or gene × sex interactions. Reduced expression of both Reelin and Brain‐Derived Neurotrophic factor (BDNF) has been associated with schizophrenia in human post‐mortem studies. However, it remains unclear how Reelin and BDNF interact (gene × gene) and whether this is sex‐specific (gene × sex). This study investigated BDNF‐TrkB signaling in the hippocampus of male and female Reelin heterozygous (Rln+/?) mice. We found significantly increased levels of BDNF in the ventral hippocampus (VHP) of female, but not male Rln+/? compared to wild‐type (WT) controls. While levels of TrkB were not significantly altered, phosphorylated TrkB (pTrkB) levels were significantly lower, again only in female Rln+/? compared to WT. This translated to downstream effects with a significant decrease in phosphorylated ERK1 (pERK1). No changes in BDNF, TrkB, pTrkB or pERK1/2 were observed in the dorsal hippocampus of Rln+/? mice. Ovariectomy (OVX) had no effect in WT controls, but caused a significant decrease in BDNF expression in the VHP of Rln+/? mice to the levels of intact WT controls. The high expression of BDNF was restored in OVX Rln+/? mice by 17β‐estradiol treatment, suggesting that Rln+/? mice respond differently to an altered estradiol state than WT controls. In addition, while OVX had no significant effect on TrkB or ERK expression/phosphorylation, OVX + estradiol treatment markedly increased TrkB and ERK1 phosphorylation in Rln+/? and, to a lesser extent in WT controls, compared to intact genotype‐matched controls. These data may provide a better understanding of the interaction of Reelin and BDNF in the hippocampus, which may be involved in schizophrenia. 相似文献
6.
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
7.
The Tau/A152T mutation,a risk factor for frontotemporal‐spectrum disorders,leads to NR2B receptor‐mediated excitotoxicity 下载免费PDF全文
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
8.
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
9.
Spontaneous neural activity is required for the establishment and maintenance of the olfactory sensory map 总被引:3,自引:0,他引:3
We have developed a genetic approach to examine the role of spontaneous activity and synaptic release in the establishment and maintenance of an olfactory sensory map. Conditional expression of tetanus toxin light chain, a molecule that inhibits synaptic release, does not perturb targeting during development, but neurons that express this molecule in a competitive environment fail to maintain appropriate synaptic connections and disappear. Overexpression of the inward rectifying potassium channel, Kir2.1, diminishes the excitability of sensory neurons and more severely disrupts the formation of an olfactory map. These studies suggest that spontaneous neural activity is required for the establishment and maintenance of the precise connectivity inherent in an olfactory sensory map. 相似文献
10.