Efficient repair of bulky anti-BPDE DNA adducts from non-transcribed DNA strand requires functional p53 but not p21(waf1/cip1) and pRb

Wild-type p53 protein is known to regulate the global genomic repair (GGR), removing bulky chemical DNA adducts as well as cyclobutane pyrimidine dimers from the genome overall and from non-transcribed strands (NTS) in DNA. To investigate the role of cellular factor(s) relevant to p53 regulated DNA repair processes, we examined the repair kinetics of chemical carcinogen, anti-benzo[a]pyrene-diol epoxide (anti-BPDE), induced bulky DNA adducts in normal human mammary epithelial cells (HMECs) and HMEC transformed by human papillomavirus (HPV)-16E6 or -16E7 oncoproteins, which, respectively targets p53 or pRb proteins for degradation. The results show that the removal of anti-BPDE DNA adducts from the genome overall and NTS by GGR was significantly reduced in HPV-16E6 protein expressing cells as compared to that in normal and HPV-16E7 protein expressing cells, indicating the role of p53 and not pRb in nucleotide excision repair (NER). We further determined the potential effects of the p53-regulated p21(waf1/cip1) gene product in NER in human colon carcinoma, HCT116 cells expressing wild-type p53 but different p21(waf1/cip1) genotypes (p21+/+, p21+/-, p21-/-). The results donot show a discernible difference in the removal of anti-BPDE DNA adducts from the genome overall and the transcribed strand (TS) and NTS irrespective of the presence or absence of p21(waf1/cip1) expression. Based on these results, we suggest that: (i) the wild-type p53 function but not p21(waf1/cip1) expression is necessary for GGR of chemical induced bulky DNA adducts; (ii) the Rb gene product does not play a significant role in NER; and (iii) the modulation of NER by p53 may be independent of its function in the regulation of cell cycle arrest upon chemically induced DNA damage.     

一株海草沉积物菲降解菌的筛选、鉴定和降解特性

【背景】多环芳烃(Polycyclic Aromatic Hydrocarbons,PAHs)是一类高毒性的有机污染物,在海洋环境尤其是沿海环境中广泛分布。海草床生态系统作为沿海环境的重要组成部分,深受环境污染等人类活动的影响而处于严重衰退的状态。微生物修复是修复环境中多环芳烃污染的重要途径,具有经济简便、环境友好和无二次污染等特点。【目的】从深圳市大亚湾的海草床沉积物中筛选获得高效多环芳烃降解菌,并分析其降解特性,从而探究海草床生态系统中多环芳烃污染物的微生物修复可行性。【方法】以多环芳烃菲为唯一碳源从海草床沉积物样品中筛选菌株,再通过形态学观察、生理生化实验和16SrRNA基因序列对筛选的菌株进行鉴定,并利用特定引物扩增多环芳烃降解的功能基因——双加氧酶(nidA)基因,最后通过培养实验分析该菌株对菲的降解特性。【结果】筛选出一株高效降解菲的菌株SCSIO 43702,经鉴定为玫瑰杆菌属(Roseovarius)的潜在新菌,并成功扩增得到双加氧酶相似(nidA like)基因;培养实验结果表明,玫瑰杆菌SCSIO 43702在10 d内对100 mg/L菲的降解率最高可达96%,而且其对菲的最适降解条件为:温度30°C、pH值7.5和8.0、盐度3%。【结论】玫瑰杆菌SCSIO 43702凭借其良好的菲降解能力和较强的环境适应性,具有进一步被开发为微生物菌剂以用于多环芳烃污染修复的巨大潜力,为海草床生态系统中多环芳烃污染的微生物修复研究提供了理论依据和可利用的微生物资源。     

Effect of sodium nitroprusside on H+-ATPase activity and ATP concentration in Candida albicans

ATP hydrolysis by plasma membrane H+-ATPase from Candida albicans has been investigated in presence of nitric oxide and various nutrients (sugars and amino acids). Sodium nitroprusside (SNP) was used as nitric oxide donor. It was found that ATP concentration decreased in SNP treated cells which was more in presence of sugars like glucose, xylose and 2-deoxy-D-glucose and amino acids as compared to their respective controls. The activity of H+-ATPase from plasma membrane decreased by 70 % in SNP treated cells. Both in vivo and in vitro treatments of SNP showed almost similar effects of decrease in ATPase activity. Effect of SNP was more pronounced in presence of nutrients. Interestingly, it was observed that vanadate did not show any independent effect in presence of nitric oxide. Several workers have reported similar type of results with other P-type ATPases. For the first time, it was observed in the present study that in presence of nitric oxide, H+-ATPase activity decreased like other P-type ATPases. Our study indicated that NO had a significant effect on ATP synthesis and activity of H+- ATPase. In the presence of NO, the ATP concentration was decreased indicating it affected mitochondrial electron transport chain. It may be concluded that NO, not only affects (inhibit) mitochondrial electron transport chain but also interferes with H+- ATPase of plasma membrane by changing its conformation resulting in decreased activity.     

Offspring resulting from transfer of cryopreserved embryos in camel (Camelus dromedarius)

The dromedary embryos, collected at hatched blastocyst stage, survived freezing and thawing in the presence of a high concentration of ethylene glycol (7.0 mol/L) with sucrose (0.5 mol/L) and direct plunging in liquid nitrogen. The rate of survival, as judged by the morphological appearance of the embryos after thawing, was high (92%). The transfer of frozen-thawed embryos into the recipients during the breeding (n=20) and non-breeding season (n=25) resulted in two and one pregnancy, respectively. One of the two pregnant recipients, with embryos transferred during the breeding season, delivered a normal healthy male calf at term. To our knowledge, this offspring is the first camelid produced following transfer of a frozen-thawed embryo.     

Effect of nitric oxide on H+ -efflux in presence of various nutrients in Candida albicans

In the present study tentative link has been established between H+ -efflux and effect of NO in presence of various nutrients (glucose, 2-deoxy-D-glucose, xylose, proline, glutamic acid and lysine) in C. albicans using sodium nitroprusside (SNP) as a potent source of NO. It was observed that there was a decreasing trend in pH with time, in control, while SNP treated cells showed an initial decline in pH for 10-15 min, followed by an increase in pH up to 30 min. In presence of glucose there was an enhancement in H+ -efflux by 9-fold whereas proline, glutamic acid and lysine showed enhancement by 3, 6 and 1.5-fold respectively. Similar trends in increase in pH after 15 min in SNP treated cells of Candida was observed in presence of all nutrients used. It was demonstrated for the first time that H+ -ATPase of C. albicans was affected by NO.     

Retrospective review of 65 atrioesophageal fistulas post atrial fibrillation ablation

Background

Although a rare complication of catheter based ablation for atrial fibrillation (AF), atrioesophageal fistula (AEF) is a serious and fatal event [[1], [2], [3], [4], [5]]. Most reports of AEF are single cases or small case series.

Application of NIR Spectroscopy Coupled with PLS Regression for Quantification of Total Polyphenol Contents from the Fruit and Aerial Parts of Citrullus colocynthis

Introduction

Citrullus colocynthis (L.) Schrad is extensively used to treat diabetes, obesity, fever, cancer, amenorrhea, jaundice, leukemia, rheumatism, and respiratory diseases. Chemical studies have indicated the presence of several cucurbitacins, flavones, and other polyphenols in this plant. These phytochemical constituents are responsible for the interesting antioxidant and other biological activities of C. colocynthis.

Objective

In the present study, for the first time, near infrared (NIR) spectroscopy coupled with partial least square (PLS) regression analysis was used to quantify the polyphenolic phytochemicals of C. colocynthis.

Methodology

The fruit and aerial parts of the C. colocynthis were extracted individually in methanol followed by fractionation in n‐hexane, chloroform, ethyl acetate, n‐butanol, and water. Near infrared (NIR) spectra were obtained in absorption mode in the wavelength range 700–2500 nm. The PLS regression model was then built from the obtained spectral data to quantify the total polyphenol contents in the selected plant samples.

Results

The PLS regression model obtained had a R² value of 99% with a 0.98 correlationship value and a good prediction with a root mean square error of prediction (RMSEP) value of 1.89% and correlation of 0.98. These results were further confirmed through UV–vis spectroscopy and it is found that the ethyl acetate fraction has the maximum value for polyphenol contents (101.7 mg/100 g; NIR, 100.4 mg/100 g; UV–vis).

Conclusions

The polyphenolic phytochemicals of the fruit and aerial parts of C. colocynthis have been quantified successfully by using multivariate analysis in a non‐destructive, economical, precise, and highly sensitive method, which uses very simple sample preparation. Copyright © 2017 John Wiley & Sons, Ltd.     

Exploitation of synthetic-derived wheats through osmotic stress responses for drought tolerance improvement

The development of drought tolerant wheat cultivars has been slow due to lack of understanding the diagnostic physiological parameters associated with improved productivity under water stress. We evaluated responses to PEG induced osmotic stress under hydroponics in D-genome synthetic derived and bread wheat germplasm with the main aim to unravel and identify some promising attributes having role in stress tolerances. Genotypes used in this study differed in their morpho-physiological and biochemical attributes. Tolerant genotypes exhibited the ability to ameliorate harmful effects of PEG induced osmotic stress through better osmotic adjustment achieved through substantial relative water content (RWC), lowered osmotic potential, relatively stable root length having maximum water extraction capacity, significant increase in osmoprotectant concentration and relatively enhanced antioxidant activities. The results clearly revealed the importance of synthetic derivatives over check cultivars and conventional wheats in terms of osmotic stress responses. Interestingly, synthetic-derived advanced lines with Aegilops tauschii in its parentage including AWL-02, AWL-04 and AWL-07 proved superior over the best rainfed check cultivar (Wa-01). It was concluded that synthetic-derived wheats has great potential to improve a range of stress adaptive traits. It could, therefore, be recommended to be a useful strategy for allowing modern bread wheat to become adapted to a wider range of environments in future climate change scenarios.     

Studies of plant colonisation by closely related Bacillus amyloliquefaciens biocontrol agents using strain specific quantitative PCR assays

Certain strains of Bacillus amyloliquefaciens can colonize plants and improve growth and stress management. In order to study these effects, bacterial growth dynamics on plants and in the rhizosphere are of interest calling for specific analytical tools. For that purpose, quantitative real-time PCR (qPCR) assays were developed in order to differentiate among three closely related B. amyloliquefaciens subsp. plantarum strains (UCMB5033, UCMB5036, UCMB5113) and to determine their levels with high accuracy. Oligonucleotide primers were designed for strain unique gene sequences and used for SYBR green based qPCR analysis. Standard curves covered a wide linear range (10⁶) of DNA amounts with the lowest detection level at 50 fg. Post-reaction melting curve analysis showed only a single product. Accurate threshold cycles were obtained, even in the presence of high excess of related Bacillus strains and total bacterial DNA from soil. Analysis of Bacillus colonisation after seed treatment of two oilseed rape cultivars (Oase and Ritz) grown on agar support showed a time dependent effect but that the bacteria mostly were found on root tissues and little on green tissues. The colonisation on plants grown in soil varied among the Bacillus strains where Oase seemed to house more bacteria than Ritz. Applied as a mixture, all three Bacillus strains co-existed on the roots of plants grown in soil. The qPCR assay in combination with other techniques will be a powerful tool to study plant interactions of these B. amyloliquefaciens biocontrol agents to further understand the requirements for successful interactions and improvement of plant properties.     

Assessment of Urinary Iodine Excretion Among Normal Kuwaiti Adults

This study was performed to investigate the status of iodine intake among the Kuwaiti population and its effect on thyroid function. The study group was comprised of 139 females and 86 males with a mean age of 33 and 35 years, respectively. Urinary iodine excretion (UIE) and serum free T4 (FT4), thyrotropin hormone (TSH), antiperoxidase antibodies (anti-TPOAb), and antithyroglobulin antibodies (anti-TGAb) were determined. Median UIE was 148 µg/L (within the recommended level by the World Health Organization [WHO]). However, UIE levels of <100 and <50 µg/L were detected in both male and female groups, respectively. Serum levels of TSH and FT4 were normal for all except one of the participants who suffered from hyperthyroidism, possibly as a result of elevated iodine intake, which was reflected in an increased UIE of 590 µg/L. Elevated anti-TPOAb >75 IU/mL and anti-TGAb >150 IU/mL were detected in 15% and 34% of subjects; only 10% of them had elevated levels of both anti-TPOAb and anti-TGAb. Thus, based on the WHO recommendations, the iodine intake for the Kuwaiti population is adequate. However, it is recommended that a national study be conducted by the appropriate authority in order to eliminate any artifacts which may have appeared in this study.