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151.
S?awomir Kumala Yasmina Hadj-Sahraoui Joanna Rzeszowska-Wolny Ronald Hancock 《Nucleic acids research》2012,40(19):9417-9428
The accessibility of DNA in chromatin is an essential factor in regulating its activities. We studied the accessibility of the DNA in a ∼170 kb circular minichromosome to DNA-cleaving reagents using pulsed-field gel electrophoresis and fibre-fluorescence in situ hybridization on combed DNA molecules. Only one of several potential sites in the minichromosome DNA was accessible to restriction enzymes in permeabilized cells, and in growing cells only a single site at an essentially random position was cut by poisoned topoisomerase II, neocarzinostatin and γ-radiation, which have multiple potential cleavage sites; further sites were then inaccessible in the linearized minichromosomes. Sequential exposure to combinations of these reagents also resulted in cleavage at only a single site. Minichromosome DNA containing single-strand breaks created by a nicking endonuclease to relax any unconstrained superhelicity was also cut at only a single position by a restriction enzyme. Further sites became accessible after ≥95% of histones H2A, H2B and H1, and most non-histone proteins were extracted. These observations suggest that a global rearrangement of the three-dimensional packing and interactions of nucleosomes occurs when a circular minichromosome is linearized and results in its DNA becoming inaccessible to probes. 相似文献
152.
Influence of Morphological Variability and Habitat on the Chemical Composition of Essential Oils of an Algerian Endemic Origanum Species (Origanum floribundum Munby) 下载免费PDF全文
The genus Origanum L. (Lamiaceae) enjoys a socioeconomic interest and constitutes one of the most popular spices. In the literature, the study of this taxon is limited mainly to the chemical composition, antimicrobial, antifungal, and antioxidant activities of the essential oils. In Algeria, few works have been done in this area, including the endemic and rare species: Origanum floribundum Munby . In this study, our contribution highlights the influence of the ecological parameters and of the variation of morphological traits on the chemical composition and the antioxidant activity of the essential oils of six populations. The major oils constituents are carvacrol, γ‐terpinene, and p‐cymene with carvacrol predominance (31.8 – 60.8%) in over five populations (MS1 – MS4 and MS6). However, the population of Ain Terraeur (MS5) of which individuals present a foliar polymorphism, distinguishes itself by p‐cymene predominance (42.6%). This would denote a new chemotype and/or variety which seem well differentiated on the dendrogram of the Ascending Hierarchical Classification (A.H.C) and its foliar morphology. The antioxidant activity of the six samples evaluated by the scavenging activity of free radicals DPPH? and ABTS?+ showed a potent efficiency for the sample with foliar polymorphism population (IC50 = 51.6 ± 0.31 and 12.71 ± 0.37 μg/ml, respectively). 相似文献
153.
Jill M. Shephard Peter Galbusera Bart Hellemans Arnela Jusic Yasmina Akhandaf 《Conservation Genetics》2009,10(5):1525-1528
The White Stork (Ciconia ciconia) has an extensive European breeding distribution. There have been significant demographic changes since the 1930s, with country-specific
extinctions throughout the western distribution since the mid-1940s. Following various reintroduction programs significant
concerns have been raised about the geographic origins of introduced storks, and the effect this may have on individual biology,
particularly breeding success. Here we report on seven new microsatellite markers developed for C. ciconia that have been successfully combined in a series of multiplex PCR’s with six markers previously described for the Wood Stork. 相似文献
154.
S. Aouichat Bouguerra M. C. Bourdillon Y. Dahmani F. Bekkhoucha 《Experimental diabetes research》2001,2(1):37-46
In this report, we have shown that the standard
laboratory diet administered to Psammomys obesus
(sand rat) from Beni Abbes in Algeria, induced a
non-insulin dependant diabetes, characterised by
increase of body weight (p<0.001) as well as
hyperinsulinemia, hyperglycemia and hypercholesterolemia.
In cultured aortic smooth muscle
cells (SMC) of sand rats, type I and type III collagen
biosynthesis and insulin effects, at low dose, on
these parameters were investigated. In all
experimental conditions of cultured SMC study, The
α chains of type I collagen were analysed by
immunoblotting in media and cells.Metabolic radiolabelling and Immunochemical
procedures revealed that, in diabetic state, synthetic
SMC (SMCs) actively produce type I and III
collagen which are synthesised in the cells and
secreted in the medium; type I collagen was
predominant as compared with type III collagen.
Diabetes enhanced the collagen synthesis. Low dose
of Insulin added to the medium, during 48h of
incubation, induced a marked reduction in the
synthesis of collagen types, especially type I
collagen. 相似文献
155.