RNA-Seq Reveals the Effect of Ethylene on the Volatile Organic Components (VOCs) of Cavendish Banana at Different Post-harvesting Stages

Aroma serves as one of the decisive factors influencing the value of banana commodities. Most of characteristic volatile organic components (VOCs) are formed during post-harvesting. However, the changing of VOCs of banana at different post-harvesting stages remain ambiguous. In this study, the VOCs of Cavendish banana for the four typical post-harvesting stages (green stage/half of yellow stage/yellow ripening stage/over ripening stage) are clarified using headspace solid phase micro-extraction (HS-SPME), combined with gas chromatography-mass spectrometry (GC–MS). The results inferred that the relative content of branched-chain esters such as acetate and butyrate, which form the main contributors of aroma in bananas, is higher in the T2 and T3 stages. Further, RNA-Seq technology was employed to clarify the formation mechanism of banana aroma in the post-harvesting stage. The MaTGL4 gene of the linoleic acid metabolism pathway and the MaBCAT3 and MaBCAT5 genes of the valine, leucine and isoleucine degradation pathway in banana suggest the expression is active late in the ripening stage, and the upregulated expression of these genes is analogous to the formation of aroma components such as branched-chain esters and hexenal. The above results not only provide baseline data on the differences in physical and chemical properties of VOCs in various post-harvesting stages of banana production, but also provide theoretical guidance facilitating the subsequent improvement of the commercial value of bananas through genetic improvement.

     

The implication of cigarette smoking and cessation on macrophage cholesterol efflux in coronary artery disease patients

We investigated ATP-binding cassette transporters A1/G1 expression and function in mediating cholesterol efflux by examining the macrophages of cigarette-smoking patients with coronary artery disease (CAD) before and after smoking abstinence. Peripheral blood monocyte cells were collected from nonsmokers (n = 17), non-CAD (NCAD) smokers (n = 35), and CAD smokers (n = 32) before and after 3 months of smoking cessation. We found that the ABCA1 expression level was lower in macrophages from NCAD and CAD smokers than from nonsmokers at baseline. The ABCA1 function of mediating cholesterol efflux was reduced in NCAD and CAD smokers as compared with nonsmokers. After 3 months of smoking cessation, ABCA1 expression and function were improved in CAD smokers. However, ABCG1 expression and function did not change after smoking cessation. Furthermore, ABCA1 expression was inhibited by tar in human acute monocytic leukemia cell line THP-1-derived macrophages through the inhibition of liver X receptors. Nicotine and carbon monoxide did not inhibit ABCA1 expression. Our results indicate that chronic cigarette smoking impaired ABCA1-mediated cholesterol efflux in macrophages and that tobacco abstinence reversed the function and expression of ABCA1, especially in CAD patients. It was tobacco tar, rather than nicotine or carbon monoxide, that played a major role in the tobacco-induced disturbance of cellular cholesterol homeostasis.     

Dysregulation of Claudin family genes in colorectal cancer in a Chinese population

Claudins play an important role in tumor metastasis and in invasiveness of colorectal cancer (CRC). We have evaluated the relationship between CRC and expression of the claudin genes in Chinese patients with CRC. We measured CLDN1 and CLDN7 mRNA using quantitative PCR, and protein levels with immunohistochemistry in cancer tissues and adjacent normal tissue. Cancer tissues had significantly higher levels of CLDN1, and significantly lower levels of CLDN3, CLDN4, and CLDN7 than did normal tissue. CLDN3, CLDN4, and CLDN7 expression levels were higher in CRC of the protruded type than in CRC of the infiltrative type. Expression of CLDN7 correlated with lymph node metastasis. Stage N0 cancer tissues had higher levels of CLDN7 than did stages N1 and N2, suggesting that CLDN7 expression was closely related to the extent of lymph node metastasis. CLDN1 protein was upregulated, but CLDN7 protein was downregulated in cancer tissues when compared with expression in adjacent normal tissues. In conclusion, CLDN3, CLDN4, and CLDN7 were significantly downregulated, whereas CLDN1 was significantly upregulated in CRC. The altered expression of claudin genes may play a role in the initiation and development of CRC.     

Dual function inhibitors of relevance to chronic obstructive pulmonary disease

The general strategy and rationale underlying the design of COPD therapeutics that possess protease inhibitory activity and are also capable of releasing a species that attenuates inflammation by inhibiting caspase-1, are described. The synthesis and in vitro biochemical evaluation of a dual function molecule that sequentially inhibits HNE and caspase-1 in a time-dependent manner is reported.     

应用双质粒共表达体系提高融合蛋白GGH在毕赤酵母GS115中的表达量

为实现人胰高血糖素样肽-1-人血清白蛋白融合蛋白 ((GLP-1A2G)2-HSA,简称GGH) 的规模化制备,通过pPICZαB与pPIC9K双质粒共表达体系提高融合蛋白GGH在毕赤酵母中的表达量。首先运用PCR技术扩增出融合蛋白GGH的基因片段,构建了表达质粒pPICZαB-ggh,并电转至经载体pPIC9K-ggh异位整合的GGH分泌型菌株——毕赤酵母GS115/F2;然后采用免疫学方法并结合高浓度抗生素筛选获得高产菌GS115/F3,在30 ℃,3％甲醇诱导80 h后GGH的表达量达到了491 m     

Determination of uremic solutes in biological fluids of chronic kidney disease patients by HPLC assay

During chronic kidney disease (CKD), solutes called uremic solutes, accumulate in blood and tissues of patients. We developed an HPLC method for the simultaneous determination of several uremic solutes of clinical interest in biological fluids: phenol (Pol), indole-3-acetic acid (3-IAA), p-cresol (p-C), indoxyl sulfate (3-INDS) and p-cresol sulfate (p-CS). These solutes were separated by ion-pairing HPLC using an isocratic flow and quantified with a fluorescence detection. The mean serum concentrations of 3-IAA, 3-INDS and p-CS were 2.12, 1.03 and 13.03 μM respectively in healthy subjects, 3.21, 17.45 and 73.47 μM in non hemodialyzed stage 3-5 CKD patients and 5.9, 81.04 and 120.54 μM in hemodialyzed patients (stage 5D). We found no Pol and no p-C in any population. The limits of quantification for 3-IAA, 3-INDS, and p-CS were 0.83, 0.72, and 3.2 μM respectively. The within-day CVs were between 1.23 and 3.12% for 3-IAA, 0.98 and 2% for 3-INDS, and 1.25 and 3.01% for p-CS. The between-day CVs were between 1.78 and 5.48% for 3-IAA, 1.45 and 4.54% for 3-INDS, and 1.19 and 6.36% for p-CS. This HPLC method permits the simultaneous and quick quantification of several uremic solutes for daily analysis of large numbers of samples.