Endogenous glutathione levels modulate the frequency of both spontaneous and long wavelength ultraviolet induced mutations in human cells

Spontaneous and induced mutations at the hypoxanthine guanine phosphoribosyt transferase locus have been measured in cultured human lymphoblastoid (TK6) cell populations under conditions in which cellular glutathione has been severely depleted by overnight treatment with buthionine-S,R-sulfoximine. At maximum levels of glutathione depletion, the increase in spontaneous frequency is at least 5-fold, a finding consistent with the possibility that cellular redox state can modulate the levels of pre-mutagenic damage arising as a result of normal metabolism in cultured human cells. Glutathione depletion does not lead to a significant enhancement in the frequency of mutants that arise as a result of irradiation at 313 run but does lead to a 3-fold increase in mutations resulting from irradiation at 365 nm. These results indicate that glutathione may quench reactive intermediates that would otherwise lead to spontaneous mutations as well as a fraction of UVA radiation-induced premutagenic damag

Endogenous glutathione levels modulate the frequency of both spontaneous and long wavelength ultraviolet induced mutations in human cells

Spontaneous and induced mutations at the hypoxanthine guanine phosphoribosyl transferase locus have been measured in cultured human lymphoblastoid (TK6) cell populations under conditions in which cellular glutathione has been severely depleted by overnight treatment with buthionine-S,R-sulfoximine. At maximum levels of glutathione depletion, the increase in spontaneous frequency is at least 5-fold, a finding consistent with the possibility that cellular redox state can modulate the levels of pre-mutagenic damage arising as a result of normal metabolism in cultured human cells. Glutathione depletion does not lead to a significant enhancement in the frequency of mutants that arise as a result of irradiation at 313 nm but does lead to a 3-fold increase in mutations resulting from irradiation at 365 nm. These results indicate that glutathione may quench reactive intermediates that would otherwise lead to spontaneous mutations as well as a fraction of UVA radiation-induced premutagenic damag

lpxC and yafS are the Most Suitable Internal Controls to Normalize Real Time RT-qPCR Expression in the Phytopathogenic Bacteria Dickeya dadantii

Background: Quantitative RT-PCR is the method of choice for studying, with both sensitivity and accuracy, the expression of genes. A reliable normalization of the data, using several reference genes, is critical for an accurate quantification of gene expression. Here, we propose a set of reference genes, of the phytopathogenic bacteria Dickeya dadantii and Pectobacterium atrosepticum, which are stable in a wide range of growth conditions. [br/] Results: We extracted, from a D. dadantii micro-array transcript profile dataset comprising thirty-two different growth conditions, an initial set of 49 expressed genes with very low variation in gene expression. Out of these, we retained 10 genes representing different functional categories, different levels of expression (low, medium, and high) and with no systematic variation in expression correlating with growth conditions. We measured the expression of these reference gene candidates using quantitative RT-PCR in 50 different experimental conditions, mimicking the environment encountered by the bacteria in their host and directly during the infection process in planta. The two most stable genes (ABF-0017965 (lpxC) and ABF-0020529 (yafS) were successfully used for normalization of RT-qPCR data. Finally, we demonstrated that the ortholog of lpxC and yafS in Pectobacterium atrosepticum also showed stable expression in diverse growth conditions. [br/] Conclusions: We have identified at least two genes, lpxC (ABF-0017965) and yafS (ABF-0020509), whose expressions are stable in a wide range of growth conditions and during infection. Thus, these genes are considered suitable for use as reference genes for the normalization of real-time RT-qPCR data of the two main pectinolytic phytopathogenic bacteria D. dadantii and P. atrosepticum and, probably, of other Enterobacteriaceae. Moreover, we defined general criteria to select good reference genes in bacteria

Transiting exoplanets from the CoRoT space mission VIII. CoRoT-7b: the first Super-Earth with measured radius

We report the discovery of very shallow (DF/F = 3.4 10-4), periodic dips in the light curve of an active V = 11.7 G9V star observed by the CoRoT satellite, which we interpret as due to the presence of a transiting companion. We describe the 3-colour CoRoT data and complementary ground-based observations that support the planetary nature of the companion. Methods. We use CoRoT color information, good angular resolution ground-based photometric observations in- and out- of transit, adaptive optics imaging, near-infrared spectroscopy and preliminary results from Radial Velocity measurements, to test the diluted eclipsing binary scenarios. The parameters of the host star are derived from optical spectra, which were then combined with the CoRoT light curve to derive parameters of the companion. We examine carefully all conceivable cases of false positives, and all tests performed support the planetary hypothesis. Blends with separation larger than 0.40 arcsec or triple systems are almost excluded with a 8 10-4 risk left. We conclude that, as far as we have been exhaustive, we have discovered a planetary companion, named CoRoT-7b, for which we derive a period of 0.853 59 +/- 3 10-5 day and a radius of Rp = 1.68 +/- 0.09 REarth. Analysis of preliminary radial velocity data yields an upper limit of 21 MEarth for the companion mass, supporting the finding. CoRoT-7b is very likely the first Super-Earth with a measured radius.Comment: Accepted in Astronomy and Astrophysics; typos and language corrections; version sent to the printer w few upgrade

Dermatofibrosarcoma protuberans treated by micrographic surgery

Dermatofibrosarcoma protuberans is an uncommon cutaneous tumour which rarely metastasises. However, local recurrence following apparently adequate surgical excision is well recognised, presumably as a result of sub-clinical contiguous growth, for which micrographically controlled excision would be a logical treatment. A retrospective study of all patients treated by micrographic surgery, from April 1995–March 2000, at a tertiary skin oncology centre. Twenty-one patients (11 males), age 14 to 71 years with dermatofibrosarcoma protuberans on the trunk (10 patients), groin (four), head and neck (four), and limbs (three) were treated. In 15 patients one micrographic layer cleared the tumour, and four were cleared with two layers. For one patient the second stage was completed by conventional excision guided by positive margins. Another patient with a multiply recurrent perineal dermatofibrosarcoma protuberans, not cleared in one area after two layers, died from a pulmonary embolus before total clearance could be achieved. There was no correlation between tumour size and lateral excision margin. No recurrence was observed during the follow-up, from 21 to 80 months, median 47 months. The study provides further support for micrographic surgery as the treatment of choice for dermatofibrosarcoma protuberans

The xylan utilization system of the plant pathogen Xanthomonas campestris pv campestris controls epiphytic life and reveals common features with oligotrophic bacteria and animal gut symbionts

Xylan is a major structural component of plant cell wall and the second most abundant plant polysaccharide in nature.Here, by combining genomic and functional analyses, we provide a comprehensive picture of xylan utilization by Xanthomonas campestris pv campestris (Xcc) and highlight its role in the adaptation of this epiphytic phytopathogen to the phyllosphere. The xylanolytic activity of Xcc depends on xylan-deconstruction enzymes but also on transporters, including two TonB-dependent outer membrane transporters (TBDTs) which belong to operons necessary for efficient growth in the presence of xylo-oligosaccharides and for optimal survival on plant leaves. Genes of this xylan utilization system are specifically induced by xylo-oligosaccharides and repressed by a LacI-family regulator named XylR. Part of the xylanolytic machinery of Xcc, including TBDT genes, displays a high degree of conservation with the xylose-regulon of the oligotrophic aquatic bacterium Caulobacter crescentus. Moreover, it shares common features, including the presence of TBDTs, with the xylan utilization systems of Bacteroides ovatus and Prevotella bryantii, two gut symbionts. These similarities and our results support an important role for TBDTs and xylan utilization systems for bacterial adaptation in the phyllosphere, oligotrophic environments and animal guts

Exchange rate volatility and capital inflows: role of financial development

There is vast literature examining the impact of exchange rate volatility on various macroeconomic aggregates such as economic growth, trade flows, domestic investment, and more recently capital flows. However, these studies have ignored the role of financial development while examining the impact of exchange rate volatility on capital flows. This study aims to analyze the impact of exchange rate volatility on capital inflows towards developing countries by incorporating the role of financial development over the time period 1980–2013. In this regard, the behavior of two types of capital flows is examined: physical capital inflows measured as foreign direct investment, and financial inflows quantified through remittance inflows. The empirical investigation comprises the direct as well as indirect effect of exchange rate volatility on capital inflows. The study employs dynamic system GMM estimation technique to empirically estimate the effect of exchange rate volatility on capital inflows. The empirical results of the study identify that exchange rate volatility dampens both physical and financial inflows towards developing countries. The indirect impact of exchange rate volatility through financial development, however, turns out positive and statistically significant. This finding reflects that financial development helps in reduc- ing the harmful impact of exchange rate volatility on capital inflows. Hence, the study concludes that a developed financial system is an important channel through which developing countries may improve capital inflows in the long run.info:eu-repo/semantics/publishedVersio