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991.
Redrawing the map: mtDNA provides new insight into the distribution and diversity of short‐finned pilot whales in the Pacific Ocean 下载免费PDF全文
Amy M. Van Cise Phillip A. Morin Robin W. Baird Aimee R. Lang Kelly M. Robertson Susan J. Chivers Robert L. Brownell Jr. Karen K. Martien 《Marine Mammal Science》2016,32(4):1177-1199
Correlations between morphological and genetic data provide evidence to delineate species or evolutionarily significant units, which then become the units to conserve in management plans. Here, we examine the distribution and genetic differentiation of two morphotypes of short‐finned pilot whale (Globicephala macrorhynchus) in the Pacific Ocean. Mitochondrial control region sequences from 333 samples were combined with 152 previously published sequences to describe genetic variability globally and population structure in the Pacific. Although genetic variability is low, we found strong differentiation at both broad and local levels across the Pacific. Based on genetics, two types are distributed throughout the Pacific, one predominantly in the eastern Pacific and the other in the western and central Pacific. In the eastern Pacific Ocean, no correlation was found between distribution and sea surface temperature. The two types have broad latitudinal ranges, suggesting their distributions are likely driven by more complex factors, such as prey distribution, rather than sea surface temperature. 相似文献
992.
Axel Van Der Gucht Ouidad Zehou Soraya Djelbani-Ahmed Laurence Valeyrie-Allanore Nicolas Ortonne Pierre Brugières Pierre Wolkenstein Alain Luciani Alain Rahmouni Emilie Sbidian Emmanuel Itti 《PloS one》2016,11(3)
Background
To investigate the diagnostic and prognostic performances of 18F-FDG PET/CT measures of metabolic tumour burden in patients with neurofibromatosis type-1 (NF1), suspect of malignant transformation.Methods
This retrospective study included 49 patients (15–60 years old, 30 women) with a diagnosis of NF1, followed in our Reference Centre for Rare Neuromuscular Diseases, who presented clinical signs of tumour progression (pain, neurological deficit, tumour growth). Quantitative metabolic parameters were measured on 149 tumoral targets, using semi-automatic software and the best cut off values to predict transformation was assessed by Receiver Operating Characteristics (ROC) analysis. Prognostic value of PET/CT metabolic parameters was assessed by Kaplan-Meier estimates of overall survival.Results
Lesions were histologically documented in 40 patients: a sarcomatous transformation was found in 16, a dysplastic neurofibroma (NF) in 7, and a benign NF in 17; in the remaining 9 patients, a minimal follow-up of 12 mo (median 59 mo) confirmed the absence of transformation. The optimal cut off values for detection of malignant transformation were, in decreasing order of area under the ROC curves, a tumour-to-liver (T/L) ratio >2.5, SUVmax > 4.5, total lesion glycolysis (TLG) > 377, total metabolic tumour volume (TMTV) > 88 cm3, and heterogeneity index (HIsuv) > 1.69. The best prognostic marker was the TLG: the 4-y estimates of survival were 97% [95% CI, 90% - 100%] in patients with TLG ≤ 377 vs. 27% [95% CI, 5% - 49%] in patients with TLG > 377 (P < 0.0001; χ2 27.85; hazard ratio 13.27 [95% CI, 3.72–47.35]). T/L ratio, SUVmax and TMTV demonstrated slightly lower performance to predict survival, with χ2 ranging 14.41–19.12. The HIsuv index was not predictive of survival.Conclusion
Our study demonstrates that TLG and TMTV, as PET/CT measures of metabolic tumour burden, may be used clinically to identify sarcomatous transformation in patients with NF1 and predict overall survival, with a higher specificity for the TLG. Conventional measures such as the SUVmax, and T/L ratio also demonstrate high prognostic value. 相似文献993.
Marta Sebastián Alastair F Smith José M González Helen F Fredricks Benjamin Van Mooy Michal Koblí?ek Joost Brandsma Grielof Koster Mireia Mestre Behzad Mostajir Paraskevi Pitta Anthony D Postle Pablo Sánchez Josep M Gasol David J Scanlan Yin Chen 《The ISME journal》2016,10(4):968-978
Upon phosphorus (P) deficiency, marine phytoplankton reduce their requirements for P by replacing membrane phospholipids with alternative non-phosphorus lipids. It was very recently demonstrated that a SAR11 isolate also shares this capability when phosphate starved in culture. Yet, the extent to which this process occurs in other marine heterotrophic bacteria and in the natural environment is unknown. Here, we demonstrate that the substitution of membrane phospholipids for a variety of non-phosphorus lipids is a conserved response to P deficiency among phylogenetically diverse marine heterotrophic bacteria, including members of the Alphaproteobacteria and Flavobacteria. By deletion mutagenesis and complementation in the model marine bacterium Phaeobacter sp. MED193 and heterologous expression in recombinant Escherichia coli, we confirm the roles of a phospholipase C (PlcP) and a glycosyltransferase in lipid remodelling. Analyses of the Global Ocean Sampling and Tara Oceans metagenome data sets demonstrate that PlcP is particularly abundant in areas characterized by low phosphate concentrations. Furthermore, we show that lipid remodelling occurs seasonally and responds to changing nutrient conditions in natural microbial communities from the Mediterranean Sea. Together, our results point to the key role of lipid substitution as an adaptive strategy enabling heterotrophic bacteria to thrive in the vast P-depleted areas of the ocean. 相似文献
994.
995.
Roeland Van Wijk Marij Welters Jan E. M. Souren Hans Ovelgonne Fred A. C. Wiegant 《Journal of cellular physiology》1993,155(2):265-272
In this work, we demonstrate that a nonlethal dose of arsenite administered to quiescent C3H10T1/2 fibroblasts can enhance the mitogenic effect of suboptimal concentrations of serum. The mitogenic effect was dependent on the serum concentration and on the time interval between the administration of arsenite and that of serum. This suggests that mitogen sensitivity changes in time after arsenite treatment. It is shown that the concentrations of arsenite that enhance the mitogenic effect of serum also increase the mRNA levels of c-fos, HSP68, and HSP84 and induce the specific synthesis of Heat Shock Proteins (HSPs). The physiological significance of this phenomenon is most likely to counteract the long-term toxic effect of arsenite by early induction of compensation for cell loss. © 1993 Wiley-Liss, Inc. 相似文献
996.
997.
Gerlind Sulzenbacher Willy J. Peumans Els J.M. Van Damme 《Journal of molecular biology》2010,400(4):715-723
A lectin from the phytopathogenic ascomycete Sclerotinia sclerotiorum that shares only weak sequence similarity with characterized fungal lectins has recently been identified. S. sclerotiorum agglutinin (SSA) is a homodimeric protein consisting of two identical subunits of ∼ 17 kDa and displays specificity primarily towards Gal/GalNAc. Glycan array screening indicates that SSA readily interacts with Gal/GalNAc-bearing glycan chains. The crystal structures of SSA in the ligand-free form and in complex with the Gal-β1,3-GalNAc (T-antigen) disaccharide have been determined at 1.6 and 1.97 Å resolution, respectively. SSA adopts a β-trefoil domain as previously identified for other carbohydrate-binding proteins of the ricin B-like lectin superfamily and accommodates terminal non-reducing galactosyl and N-acetylgalactosaminyl glycans. Unlike other structurally related lectins, SSA contains a single carbohydrate-binding site at site α. SSA reveals a novel dimeric assembly markedly dissimilar to those described earlier for ricin-type lectins. The present structure exemplifies the adaptability of the β-trefoil domain in the evolution of fungal lectins. 相似文献
998.
999.
Hoare S Zou Y Purohit V Krishnasamy R Skorvaga M Van Houten B Geacintov NE Basu AK 《Biochemistry》2000,39(40):12252-12261
The UvrABC nuclease system from Escherichia coli removes DNA damages induced by a wide range of chemical carcinogens with variable efficiencies. The interactions with UvrABC proteins of the following three lesions site-specifically positioned in DNA, and of known conformations, were investigated: (i) adducts derived from the binding of the (-)-(7S,8R,9R,10S) enantiomer of 7,8-dihydroxy-9, 10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene [(-)-anti-BPDE] by cis-covalent addition to N(2)-2'-deoxyguanosine [(-)-cis-anti-BP-N(2)-dG], (ii) an adduct derived from the binding of the (+)-(1R,2S,3S,4R) enantiomer of 1,2-dihydroxy-3,4-epoxy-1,2,3, 4-tetrahydro-5-methylchrysene [(+)-anti-5-MeCDE] by trans addition to N(2)-2'-deoxyguanosine [(+)-trans-anti-MC-N(2)-dG], and (iii) a C8-2'-deoxyguanosine adduct (C8-AP-dG) formed by reductively activated 1-nitropyrene (1-NP). The influence of these three different adducts on UvrA binding affinities, formation of UvrB-DNA complexes by quantitative gel mobility shift analyses, and the rates of UvrABC incision were investigated. The binding affinities of UvrA varied among the three adducts. UvrA bound to the DNA adduct (+)-trans-anti-MC-N(2)-dG with the highest affinity (K(d) = 17 +/- 2 nM) and to the DNA containing C8-AP-dG with the least affinity (K(d) = 28 +/- 1 nM). The extent of complex formation with UvrB was also the lowest with the C8-AP-dG adduct. 5' Incisions occurred at the eighth phosphate from the modified guanine. The major 3' incision site corresponded to the fifth phosphodiester bond for all three adducts. However, additional 3' incisions were observed at the fourth and sixth phosphates in the case of the C8-AP-dG adduct, whereas in the case of the (-)-cis-anti-BP-N(2)-dG and (+)-trans-anti-MC-N(2)-dG lesions additional 3' cleavage occurred at the sixth and seventh phosphodiester bonds. Both the initial rate and the extent of 5' and 3' incisions revealed that C8-AP-dG was repaired less efficiently in comparison to the (-)-cis-anti-BP-N(2)-dG and (+)-trans-anti-MC-N(2)-dG containing DNA adducts. Our study showed that UvrA recognizes conformational changes induced by structurally different lesions and that in certain cases the binding affinities of UvrA and UvrB can be correlated with the incision rates. The size of the bubble formed around the damaged site with mismatched bases also appears to influence the incision rates. A particularly noteworthy finding in this study is that UvrABC repair of a substrate with no base opposite C8-AP-dG was quite inefficient as compared to the same adduct with a C opposite it. These findings are discussed in terms of the available NMR solution structures. 相似文献
1000.