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101.
Rev-erb beta is an orphan receptor that binds as a homodimer or as a monomer to DNA. The solution structure of the non-palindromic 15 bp DNA duplex d(TAGAATGTAGGTCAG), the response element of Rev-erb beta for monomeric binding, was determined by 1H and 31P NMR, energy minimization with NMR-derived restraints for distances and NOE back-calculation methods. The refined final structures have the typical overall features of B-type DNA. However, titration of this 15 bp duplex with ReDBD, the DNA binding domain of Rev-erb beta, showed large shifts of imino protons and 31P signals, suggesting major conformational changes. 相似文献
102.
In vivo control of gluconeogenesis in wild-type Neurospora crassa and in the adenylate cyclase-deficient cr-1 (crisp) mutant. 下载免费PDF全文
The rate of cycloheximide-resistant incorporation of carbon from [14C]alanine and [14C]acetate into polysaccharidic material was used to study gluconeogenic activity in wild-type Neurospora crassa and in the adenylate cyclase-deficient cr-1 (crisp-1) mutant. The wild-type efficiently utilized alanine and acetate as gluconeogenic substrates, whereas the mutant used acetate efficiently but was unable to use alanine. Cycloheximide-resistant 14C-incorporating activity was sensitive to carbon catabolite effects (repression and inactivation) in the two strains, which suggested that cyclic AMP metabolism was not involved in these regulatory responses. In the wild type, gluconeogenesis was induced by incubation of the cells in the absence of a carbon source. In contrast, cr-1 required supplementation with acetate. This finding suggested that induction of gluconeogenesis in N. crassa could be mediated by metabolites formed in carbon-starved cells. The cr-1 mutant seemed to be deficient in this process and to depend on an exogenous effector to induce gluconeogenesis. Incubation of cr-1 with cyclic AMP partially overcame the acetate requirement for induction of gluconeogenesis. 相似文献
103.
Worldwide patterns of mitochondrial DNA differentiation in the harbor seal (Phoca vitulina) 总被引:3,自引:0,他引:3
Stanley HF; Casey S; Carnahan JM; Goodman S; Harwood J; Wayne RK 《Molecular biology and evolution》1996,13(2):368-382
The harbor seal (Phoca vitulina) has one of the broadest geographic
distributions of any pinniped, stretching from the east Baltic, west across
the Atlantic and Pacific Oceans to southern Japan. Although individuals may
travel several hundred kilometers on annual feeding migrations, harbor
seals are generally believed to be philopatric, returning to the same areas
each year to breed. Consequently, seals from different areas are likely to
be genetically differentiated, with levels of genetic divergence increasing
with distance. Differentiation may also be caused by long-standing
topographic barriers such as the polar sea ice. We analyzed samples of 227
harbor seals from 24 localities and defined 34 genotypes based on 435 bp of
control region sequence. Phylogenetic analysis and analysis of molecular
variance showed that populations in the Atlantic and Pacific Oceans and
east and west coast populations of these oceans are significantly
differentiated. Within these four regions, populations that are
geographically farthest apart generally are the most differentiated and
often do not share genotypes or differ in genotype frequency. The average
corrected sequence divergence between populations in the Atlantic and
Pacific Oceans is 3.28% +/- 0.38% and those among populations within each
of these oceans are 0.75% +/- 0.69% and 1.19% +/- 0.65%, respectively. Our
results suggest that harbor seals are regionally philopatric, on the scale
of several hundred kilometers. However, genetic discontinuities may exist,
even between neighboring populations such as those on the Scottish and east
English coasts or the east and west Baltic. The mitochondrial data are
consistent with an ancient isolation of populations in both oceans, due to
the development of polar sea ice. In the Atlantic and Pacific, populations
appear to have been colonized from west to east with the European
populations showing the most recent common ancestry. We suggest the recent
ancestry of European seal populations may reflect recolonization from Ice
Age refugia after the last glaciation.
相似文献
104.
Larissa Sens Ana Caroline Arruda de Souza Lucas Antonio Pacheco Angela Camila Orbem Menegatti Mattia Mori Alessandra Mascarello Ricardo José Nunes Hernán Terenzi 《Bioorganic & medicinal chemistry》2018,26(21):5742-5750
Mycobacterium tuberculosis secretes two protein tyrosine phosphatases as virulence factors, PtpA and PtpB. Inhibition studies of these enzymes have shown significant attenuation of the M. tuberculosis growth in vivo. As PtpA mediates many effects on the regulation of host signaling ensuring the intracellular survival of the bacterium we report, for the first time, thiosemicarbazones as potential novel class of PtpA inhibitors. Several compounds were synthesized and biologically evaluated, revealing interesting results. Enzyme kinetic assays showed that compounds 5, 9 and 18 are non-competitive inhibitors of PtpA, with Ki values ranging from 1.2 to 5.6?µM. Modeling studies clarified the structure-activity relationships observed in vitro and indicated a possible allosteric binding site in PtpA structure. To the best of our knowledge, this is the first disclosure of potent non-competitive inhibitors of PtpA with great potential for future studies and development of analogues. 相似文献
105.
It is known that Neurospora crassa mycelia cultured in standard concentrations (76 to 190 µg/ml) of sulfate accumulate a low molecular weight inhibitor of tyrosinase (monophenol, dihydroxyphenylalanine: oxygen oxidorenductase; EC 1.14.1.18.1.). This is not observed in cultures grown under sulfate-limiting conditions. The chemical nature of tyrosinase inhibition was investigated. It was shown to be due to the low molecular weight sulfhydryl fraction of the extracts, in which glutathione is predominant. The concentration of low molecular weight sulfhydryl compounds decreased sharply in mycelia submitted to various treatments which also derepressed tyrosinase, such as (i) starvation in phosphate buffer, (ii) treatment with cycloheximide, and (iii) mating. These results suggest that the concentration of sulfhydryl compounds may be of physiological significance in the control of tyrosinase activity in N. crassa. 相似文献
106.
Otero L Smircich P Vieites M Ciganda M Severino PC Terenzi H Cerecetto H Gambino D Garat B 《Journal of inorganic biochemistry》2007,101(1):74-79
Metal complexes that establish interactions with DNA are being studied not only because of their potential use as therapeutic agents but also as tools for biochemistry and molecular biology. Searching for drugs with anti-trypanosome activity, we previously synthesized a series of ruthenium mixed ligand dimethyl sulfoxide complexes of the type [Ru(II)Cl(2)(DMSO)(2)L], where L is 5-nitrofurylsemicarbazone derivatives and DMSO is dimethyl sulfoxide. Though they present the ability to bind DNA, no activity against parasites in cell culture was observed. Considering their potential application as molecular tools we further analyzed the interactions with DNA through an electrophoretic approach. Non covalent withdrawal of superhelicity and a rapid nicking activity upon covalent interaction was observed. Inhibition of both effects was observed in the presence of distamycin suggesting the involvement of the DNA minor groove in the interaction with the nitrofurylsemicarbazone ruthenium complexes. In addition cleavage inhibition by dimethyl sulfoxide suggests an oxidative mechanism of action. 相似文献
107.
Neutral trehalases catalyse intracellular trehalose breakdown in the filamentous fungi Aspergillus nidulans and Neurospora crassa 总被引:1,自引:0,他引:1
108.
Background
The ABCC5 gene encodes an organic anion pump of the ATP-binding cassette (ABC) transporter family, subclass C. The exact physiological function of ABCC5 however is not known. Here, we have isolated three novel ABCC5 splice variants and characterized their role in the regulation of ABCC5 gene expression. 相似文献109.
110.
Craig R. Ely Jeffrey S. Hall Joel A. Schmutz John M. Pearce John Terenzi James S. Sedinger Hon S. Ip 《PloS one》2013,8(3)
We report on life history characteristics, temporal, and age-related effects influencing the frequency of occurrence of avian influenza (AI) viruses in four species of migratory geese breeding on the Yukon-Kuskokwim Delta, Alaska. Emperor geese (Chen canagica), cackling geese (Branta hutchinsii), greater white-fronted geese (Anser albifrons), and black brant (Branta bernicla), were all tested for active infection of AI viruses upon arrival in early May, during nesting in June, and while molting in July and August, 2006–2010 (n = 14,323). Additionally, prior exposure to AI viruses was assessed via prevalence of antibodies from sera samples collected during late summer in 2009 and 2010. Results suggest that geese are uncommonly infected by low pathogenic AI viruses while in Alaska. The percent of birds actively shedding AI viruses varied annually, and was highest in 2006 and 2010 (1–3%) and lowest in 2007, 2008, and 2009 (<0.70%). Contrary to findings in ducks, the highest incidence of infected birds was in late spring when birds first arrived from staging and wintering areas. Despite low prevalence, most geese were previously exposed to AI viruses, as indicated by high levels of seroprevalence during late summer (47%–96% across species; n = 541). Seroprevalence was >95% for emperor geese, a species that spends part of its life cycle in Asia and is endemic to Alaska and the Bering Sea region, compared to 40–60% for the other three species, whose entire life cycles are within the western hemisphere. Birds <45 days of age showed little past exposure to AI viruses, although antibodies were detected in samples from 5-week old birds in 2009. Seroprevalence of known age black brant revealed that no birds <4 years old had seroconverted, compared to 49% of birds ≥4 years of age. 相似文献