Soluble expression, purification and functional identification of a disulfide-rich conotoxin derived from Conus litteratus

Conotoxins are a diverse array of small peptides mostly with multiple disulfide bridges. These peptides become an increasing significant source of neuro-pharmacological probes and drugs as a result of the high selectivity for ion channels and receptors. Usually, the analogue of natural conotoxins is produced by means of chemical synthesis. Here, we present a simple and fast strategy of producing disulfide-rich conotoxins via recombinant expression. By fused with thioredoxin and His tag, a novel O-superfamily conotoxin lt7a was successfully expressed in Escherichia coli and purified, resulting in a high yield of recombinant lt7a about 6 mg/l. The purity of target protein is up to 95% as identified by HPLC results. Whole cell patch-clamp recording revealed that the new conotoxin blocked voltage-sensitive sodium channels in rat dorsal root ganglion neurons, indicating it might be a novel microO-conotoxin.     

海南红厚壳花香气成分采集和TCT-GC-MS分析

用鲜花循环式动态顶空技术采集红厚壳鲜花的香气成分,TCT-GC-MS联用技术分析鉴定。4-羟基-2-丁酮,双烯酮,1、2-环氧-2-甲基丁烷,1、2-环氧-3-甲基丁烷,2-乙基戊烷,3-己醇,甲基环戊烷,2-丁醇等24个成分被检测出,占总离子流出峰面积的90.28%。并对结果进行了分析讨论。     

Adult Cardiac Progenitor Cell Aggregates Exhibit Survival Benefit Both In Vitro and In Vivo

Background

A major hurdle in the use of exogenous stems cells for therapeutic regeneration of injured myocardium remains the poor survival of implanted cells. To date, the delivery of stem cells into myocardium has largely focused on implantation of cell suspensions.

Methodology and Principal Findings

We hypothesize that delivering progenitor cells in an aggregate form would serve to mimic the endogenous state with proper cell-cell contact, and may aid the survival of implanted cells. Microwell methodologies allow for the culture of homogenous 3D cell aggregates, thereby allowing cell-cell contact. In this study, we find that the culture of cardiac progenitor cells in a 3D cell aggregate augments cell survival and protects against cellular toxins and stressors, including hydrogen peroxide and anoxia/reoxygenation induced cell death. Moreover, using a murine model of cardiac ischemia-reperfusion injury, we find that delivery of cardiac progenitor cells in the form of 3D aggregates improved in vivo survival of implanted cells.

Conclusion

Collectively, our data support the notion that growth in 3D cellular systems and maintenance of cell-cell contact improves exogenous cell survival following delivery into myocardium. These approaches may serve as a strategy to improve cardiovascular cell-based therapies.     

Plastid structure and carotenogenic gene expression in red- and white-fleshed loquat (Eriobotrya japonica) fruits

Loquat (Eriobotrya japonica Lindl.) can be sorted into red- and white-fleshed cultivars. The flesh of Luoyangqing (LYQ, red-fleshed) appears red-orange because of a high content of carotenoids while the flesh of Baisha (BS, white-fleshed) appears ivory white due to a lack of carotenoid accumulation. The carotenoid content in the peel and flesh of LYQ was approximately 68 μg g(-1) and 13 μg g(-1) fresh weight (FW), respectively, and for BS 19 μg g(-1) and 0.27 μg g(-1) FW. The mRNA levels of 15 carotenogenesis-related genes were analysed during fruit development and ripening. After the breaker stage (S4), the mRNA levels of phytoene synthase 1 (PSY1) and chromoplast-specific lycopene β-cyclase (CYCB) were higher in the peel, and CYCB and β-carotene hydroxylase (BCH) mRNAs were higher in the flesh of LYQ, compared with BS. Plastid morphogenesis during fruit ripening was also studied. The ultrastructure of plastids in the peel of BS changed less than in LYQ during fruit development. Two different chromoplast shapes were observed in the cells of LYQ peel and flesh at the fully ripe stage. Carotenoids were incorporated in the globules in chromoplasts of LYQ and BS peel but were in a crystalline form in the chromoplasts of LYQ flesh. However, no chromoplast structure was found in the cells of fully ripe BS fruit flesh. The mRNA level of plastid lipid-associated protein (PAP) in the peel and flesh of LYQ was over five times higher than in BS peel and flesh. In conclusion, the lower carotenoid content in BS fruit was associated with the lower mRNA levels of PSY1, CYCB, and BCH; however, the failure to develop normal chromoplasts in BS flesh is the most convincing explanation for the lack of carotenoid accumulation. The expression of PAP was well correlated with chromoplast numbers and carotenoid accumulation, suggesting its possible role in chromoplast biogenesis or interconversion of loquat fruit.     

The association between ATM IVS 22-77 T>C and cancer risk: a meta-analysis

Background and Objectives

It has become increasingly clear that ATM (ataxia-telangiectasia-mutated) safeguards genome stability, which is a cornerstone of cellular homeostasis, and ATM IVS 22-77 T>C affects the normal activity of ATM proteins. However, the association between the ATM IVS 22-77 T>C genetic variant and cancer risk is controversial. Therefore, we conducted a systematic meta-analysis to estimate the overall cancer risk associated with the polymorphism and to quantify any potential between-study heterogeneity.

Methods

A total of nine studies including 4,470 cases and 4,862 controls were analyzed for ATM IVS 22-77 T>C association with cancer risk in this meta-analysis. Heterogeneity among articles and their publication bias were also tested.

Results

Our results showed that no association reached the level of statistical significance in the overall risk. Interestingly, in the stratified analyses, we observed an inverse relationship in lung and breast cancer.

Conclusion

Further functional research on the ATM mechanism should be performed to explain the inconsistent results in different cancer types.     

Novel potassium N-[(2S,3R,4R,5R)-2,3,4,5,6-pentahydroxylhex-1-yl]-L-amino acid dichloroplatinates(II) with high anti-tumor activity and low side reaction

To discover whether novel anti-tumor platinum agents are capable of selectively accumulating in tumor tissue, three novel potassium N-[(2S,3R,4R,5R)-2,3,4,5,6-pentahydroxylhex-1-yl]-L-amino acid dichloroplatinates(II) were prepared. At a dose of 1.67 μmol kg(-1) the in vivo anti-tumor potencies of two of the compounds were higher than that of oxaliplatin. The mortality analysis indicated that these compounds resulted in a 100% survival rate, whereas oxaliplatin lead to an 80% survival rate. The organ damage examination indicated that these compounds induced less damage than oxaliplatin. The platinum accumulation in the organs, blood and bone was significantly lower than that of oxaliplatin treated mice, while the platinum accumulation in the tumor tissue was significantly higher than that of the oxaliplatin treated mice.     

N-Acetylcysteine ameliorates lipopolysaccharide-induced organ damage in conscious rats

Lipopolysaccharide is strongly associated with septic shock, leading to multiple organ failure. It can activate monocytes and macrophages to release proinflammatory mediators such as tumor necrosis factor- (TNF-), interleukin-1 (IL-1), and nitric oxide (NO). The present experiments were designed to induce endotoxin shock by an intravenous injection ofKlebsiella pneumoniae lipopolysaccharide (LPS, 10 mg/kg) in conscious rats. Arterial pressure and heart rate (HR) were continuously monitored for 48 h after LPS administration. N-Acetyl-cysteine was used to study its effects on organ damage. Biochemical substances were measured to reflect organ functions. Biochemical factors included blood urea nitrogen (BUN), creatinine (Cre), lactic dehydrogenase (LDH), creatine phosphokinase (CPK), aspartate transferase (GOT), alanine transferase (GPT), TNF-, IL-1, methyl guanidine (MG), and nitrites/nitrates. LPS caused significant increases in blood BUN, Cre, LDH, CPK, GOT, GPT, TNF-, IL-1, MG levels, and HR, as well as a decrease in mean arterial pressure and an elevation of nitrites/nitrates. N-Acetylcysteine suppressed the release of TNF-, IL-1, and MG, but enhanced NO production. These actions ameliorate LPS-induced organ damage in conscious rats. The beneficial effects may suggest a potential chemopreventive effect of this compound in sepsis prevention and treatment.     

Does Bt rice pose risks to non‐target arthropods? Results of a meta‐analysis in China

Transgenic Bt rice expressing the insecticidal proteins derived from Bacillus thuringiensis Berliner (Bt) has been developed since 1989. Their ecological risks towards non‐target organisms have been investigated; however, these studies were conducted individually, yielding uncertainty regarding potential agroecological risks associated with large‐scale deployment of Bt rice lines. Here, we developed a meta‐analysis of the existing literature to synthesize current knowledge of the impacts of Bt rice on functional arthropod guilds, including herbivores, predators, parasitoids and detritivores in laboratory and field studies. Laboratory results indicate Bt rice did not influence survival rate and developmental duration of herbivores, although exposure to Bt rice led to reduced egg laying, which correctly predicted their reduced abundance in Bt rice agroecosystems. Similarly, consuming prey exposed to Bt protein did not influence survival, development or fecundity of predators, indicating constant abundances of predators in Bt rice fields. Compared to control agroecosystems, parasitoid populations decreased slightly in Bt rice cropping systems, while detritivores increased. We draw two inferences. One, laboratory studies of Bt rice showing effects on ecological functional groups are mainly either consistent with or more conservative than results of field studies, and two, Bt rice will pose negligible risks to the non‐target functional guilds in future large‐scale Bt rice agroecosystems in China.