摘要：
The safety, efficacy and stability of natural antioxidants have been the focus of research in the food industry, with the aim of rapidly analyzing and controlling the quality of rosemary and its extracts, a novel analytical method involving high-performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD) was developed for the simultaneous determination of rosmarinic acid, carnosol, carnosic acid, oleanolic acid and ursolic acid in rosemary. Chromatographic separation was conducted with gradient elution mode by using a Zorbax SB-C18 column (4.6 mm x 250 mm, 5 mum) with mobile phases of methanol and 0.6% acetic acid. The drift tube temperature of ELSD was 70 degrees C, and the pressure of nebulizer nitrogen gas was 40 Psi. The method developed has high sensitivity (with limits of detection from 1.3 to 8.6 mug/mL), acceptable linearity over the tested concentrations (with correlation coefficients from 0.991 to 0.999), good repeatability (with intra- and inter-day CV less than 3.1% for all analytes) and satisfactory accuracy (with recovery between 95.5% and 100.8%). The method has been demonstrated as a powerful tool for the functional ingredients analysis and quality control of rosemary and its extracts in a cost- and time-effective manner.
期刊：
Ecotoxicology and Environmental Safety,2019年172:19-25 ISSN：0147-6513
通讯作者：
Wang, Zhi
作者机构：
[Wang, Zhi; Wang, Juan] Hunan Normal Univ, Coll Life Sci, Changsha 410081, Hunan, Peoples R China.;[Yang, Huilin; Chen, Zhaoyang; Lei, Ziyan; Lv, Bo; Wang, Juan] Hunan Agr Univ, Coll Biosci & Biotechnol, Changsha 410128, Hunan, Peoples R China.;[Lv, Zhiyue] Sun Yat Sen Univ, Zhongshan Sch Med, Dept Parasitol, Guangzhou 510080, Guangdong, Peoples R China.;[Song, Qisheng] Univ Missouri, Div Plant Sci, Columbia, MO 65211 USA.
通讯机构：
[Wang, Zhi] H;Hunan Normal Univ, Coll Life Sci, Changsha 410081, Hunan, Peoples R China.
关键词：
Cd transporters;Cuticle;Cytochrome P450 enzymes;Ecdysteroids;Molting
摘要：
Cytochrome P450 enzymes (CYPs), encoded by Halloween genes, mediate the biosynthesis of molting hormone, ecdysteroids, in arthropods. In this report, the effect of heavy metal cadmium (Cd) stress on the expression of cytochrome P450 genes in the wolf spider Pardosa pseudoannulata was analyzed. The results showed the expression levels of genes encoding for Cd transporters including ABC transporters, zinc transporters, calcium channel proteins and calcium binding proteins were inhibited or induced by Cd stress. In addition, the increase in metallothionein (MT) content and glutathione peroxidase (GPX) activity and decrease in total acetylcholine esterase (AChE) activity were also detected. Apparently, these detoxification methods did not completely protect the spider from the cytotoxicity of Cd stress. Increased mortality of P. pseudoannulata was observed when they were under Cd tress. In total 569 CYP genes belonging to 62 CYP subfamilies were obtained from P. pseudoannulata RNA-seq databases. BlaxtX analysis showed that 150, 161, 11, and 40 CYP genes were similar to the genes dib, phm, sad and shd, respectively, which are thought to catalyze the biosynthesis of ecdysteroids. Gene expression analysis suggested that 25 dib encoding genes, 27 phm encoding genes, 2 sad encoding genes, and 6 shd encoding genes were differentially expressed in TS2 vs. S2 comparison (Cd-treated 2nd instar spider vs. 2nd instar spider), respectively. There were 70 dib, 70 phm and 19 shd encoding genes either upregulated or downregulated, while 3 sad encoding genes were upregulated in TS5 vs. S5 (Cd-treated 5nd instar spider vs. 5nd instar spider). Genes related to heme binding and essential for activating the CYPs were also differentially expressed. Expression levels of cuticle related genes were significant differentially expressed, implying the changes in activities of chitin synthases and chitinase. Therefore we assume that unsuccessful molting process may occur on P. pseudoannulata due to influenced ecdysteroids levels, thus increasing mortality of spider.
摘要：
A Gram-stain-positive, motile, rod-shaped bacterial strain, YN-1(T), was isolated from a rice field in the town of Jietou, Yunnan Province, PR China. Colonies were circular, 1-2 mm in diameter, creamy white, with slightly irregular margins. The isolate grew optimally at 37 degrees C, pH 7.0 and with 1.0 % (w/v) NaCl. On the basis of the results of 16S rRNA gene sequence similarity comparisons, YN-1(T) clustered together with other species of the genus Bacillus and showed highest similarities with Bacillus onubensis 0911MAR22V3(T) (98.0 %), Bacillus humi LMG22167(T) (97.5 %), 'Bacillus timonensis' 10403023 (97.4 %) and 'Bacillussinesaloumensis' P3516 (97.1 %). However, the DNA-DNA hybridization values between YN-1(T) and closely related strains of species of the genus Bacillus were well below 47 %, indicating that they represent different taxa. The average nucleotide identity and the Genome-to-Genome Distance Calculator also revealed low relatedness (below 95 and 70 %, respectively) between YN-1(T) and type strains of closely related species of the genus Bacillus. The DNA G+C content of the strain was 40 mol%. The major cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0, and C16 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids, three unidentified aminophospholipids and two other unidentified lipids. Physiological and biochemical test results were also different from those of the most closely related species. On the basis of the phenotypic, genetic and chemotaxonomic data, strain YN-1(T) is considered to represent a novel species of the genus Bacillus, for which the name Bacillusaciditolerans sp. nov. is proposed, with strain YN-1(T) (=CCTCC AB 2017280(T)=JCM 32973(T)) as the type strain.
摘要：
In this work, a label-free fluorescence biosensor for simple detection of the HIV-1 gene was proposed by using toehold-mediated strand displacement reactions (TMSDRs) combined with a non-enzymatic target recycling amplification strategy. In this system, two TMSDRs were used. In the presence of the HIV-1 gene, an autocatalytic DNA machine can be activated. This leads to the generation of numerous free G-rich sequences, which can associate with a fluorescent dye N-methylmesoporphyrin IX (NMM) to yield an amplified fluorescence signal for the target detection. This sensing platform showed a high sensitivity towards the HIV-1 gene with a detection limit as low as 1.9 pM without any labelling, immobilization, or washing steps. The designed sensing system also exhibits an excellent selectivity for the HIV-1 gene compared with other interference DNA sequences. Furthermore, the presented biosensor is robust and has been successfully applied for the detection of the HIV-1 gene in a real biological sample with satisfactory results, suggesting that this method is promising for simple and early clinical diagnosis of HIV infection. Thanks to its simplicity, cost-effectiveness and ultrasensitivity, our proposed sensing strategy provides a universal platform for the detection of other genes by substituting the target-recognition element.
摘要：
Beta diversity describes the variation in species composition between sites and is often influenced by both local and regional processes. Partitioning beta diversity into turnover (species replacement between sites) and nestedness (richness difference between sites) components may enhance our understanding of the mechanisms behind the local and regional drivers determining species composition across spatial scales. We sampled macrophyte communities in 24 lakes in two regions (Yangtze River basin and Yunnan-Guizhou plateau) of China covering broad climate and nutrient gradients. Based on both species and functional approaches, we calculated multiple-site beta diversity using the Sorensen dissimilarity index and partitioned it into turnover and nestedness coefficients crossed with two nested spatial scales: among depths within transects (transect scale) and among transects within lakes (lake scale). The overall species beta diversity and functional beta diversity (i.e. Sorensen coefficient) were significantly lower and thus more homogeneous at lake scale. Across spatial scales, species beta diversity was mainly explained by turnover patterns (56-61%) and functional beta diversity primarily by nestedness patterns (58-65%). Both local and regional drivers contributed to structuring species and functional beta diversity patterns, largely through changes in species turnover and functional nestedness, respectively. Overall, we observed a significant increase in species beta diversity and its turnover component while a decreasing trend in functional beta diversity and its nestedness component at high altitude. Our results further emphasized that the species beta diversity and its turnover component decreased at high total phosphorus concentration (TP) across the two spatial scales, while the functional beta diversity and its nestedness component decreased at high TP at the transect scale. We conclude that understanding of the relative role of local and regional drivers in determining macrophyte diversity patterns may help managers to select the most appropriate conservation strategies for preservation of biodiversity varying with the scale in focus.
摘要：
Fumarylacetoacetate hydrolase participates in positive regulation of salt stress in Arabidopsis. Fumarylacetoacetate hydrolase (FAH) catalyzes the hydrolysis of fumarylacetoacetate into fumarate and acetoacetate, the final step in the Tyr degradation pathway that is essential to animals. However, the Tyr degradation pathway is not well understood in plants. Previously, we found that mutation of the SHORT-DAY SENSITIVE CELL DEATH 1 (SSCD1) gene encoding FAH in Arabidopsis causes spontaneous cell death under short day, which first indicated that the Tyr degradation pathway also plays an important role in plants. In this study, we found that the SSCD1 gene was up-regulated by salt stress, and the sscd1 mutant was hypersensitive to salt stress. However, the double mutant of SSCD1 and HOMOGENTISATE DIOXYGENASE, in which intermediates of the Tyr degradation pathway could not be produced, displayed a normal response to salt stress. Furthermore, the sscd1 mutant showed more accumulation of reactive oxygen species (ROS) and less up-regulation of some ROS-scavenging genes such as ASCORBATE PEROXIDASE 2 and COPPER/ZINC SUPEROXIDE DISMUTASE 1 compared with wild type under salt stress. In addition, SSCD1 expression was also up-regulated by H2O2, and the sscd1 mutant exhibited hypersensitivity to oxidative stress compared with wild type. Taken together, we concluded that loss of FAH in sscd1 leads to the accumulation of Tyr degradation intermediates, which impairs the up-regulation of some ROS-scavenging genes under salt stress, causing more accumulation of ROS, resulting in the hypersensitivity of sscd1 to salt stress.
摘要：
A novel feather-degrading bacterium named CA-1 was isolated from the gut of the spider Chilobrachys guangxiensis, which degrades native whole chicken feathers within 20 h. The CA-1 was confirmed to belong to Stenotrophomonas maltophilia based on morphologic and molecular analysis. Maximum feather degradation activity of the bacterium was observed at 37 A degrees C in basal feather medium (NaCl 0.5 g/L, KH2PO4 0.3 g/L, K2HPO4 0.4 g/L, feather powder 10.0 g/L, pH 8.0), which was inhibited when glucose and ammonium nitrate were added in the medium. Furthermore, the purified enzymes under the optimal and suppressive conditions were analyzed respectively by SDS-PAGE and LC-MS/MS. Three enzymes, namely alkaline serine protease (29.1 kDa), ABC transporter permease (27.5 kDa), and alkaline phosphatase (40.8 kDa), were isolated and identified from the supernatant of the optimal culture and were considered to play principal roles. On the other hand, the potential synergic effects of the three proteins in S. maltophilia CA-1 feather degradation system were analyzed theoretically. CA-1 may product outer-membrane vesicles comprised of membranes and periplasmic proteins in the feather medium. The newly identified CA-1 and its synergic enzymes provide a new insight into further understanding the molecular mechanism of feather degradation by microbes. They also have potential application in cost-effectively degrading feathers into feeds and fertilizers through careful optimization and engineering of the three newly identified enzymes.
作者机构：
[Yun Tian] College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China;[Michael X.Zhu] Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA. Michael.X.Zhu@uth.tmc.edu
通讯机构：
[Michael X. Zhu] D;Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
关键词：
CYTOKINES;TGF-Β;A novel TRPC6-dependent;mechanism of TGF NCX Ca HCC induced migration and invasion of human;hepatocellular carcinoma cells
摘要：
Mechanisms on cancer cell migration and invasion have been major topics of cancer research and anti-cancer therapy development. Among the multiple cell signaling pathways involved in cell migration, those elicited by transforming growth factor β(TGF-β) have attracted tremendous attention. The TGF-β polypeptide cytokines include four isoforms: TGF-β1, TGF-β2, TGF-β3, and TGF-β4, which are secreted mainly from cells of white blood cell lineage, such as macrophages, T cells and platelets. However, TGF-β can also be synthesized and released from fibroblasts and cancer cells(Shi and Chen, 2017). TGF-β binds to its cell surface receptors, heterotetramers formed by the type I and type II TGF-β receptors, to evoke downstream signal transduction and thereby modulation of cell function. Much is known about the signaling pathways activated by TGF-β and its pathophysiological roles, especially the effects of TGF-β signaling on tumor growth and metastasis. Because of the complexity and diverse functional consequences of TGF-β evoked signaling pathways, the actions of TGF-β at the different developmental stages and to different cancer types are also quite different. On one hand, TGF-β can suppress cancer cell growth by inducing cell demise and/or causing cell cycle arrest. On the other hand, TGF-β may promote tumorigenesis and/or cancer metastasis through induction of migration and invasion, angiogenesis, disruption of cell adhesion,and etc.(Heldin et al., 2012). Therefore, for different cancers and a particular cancer at different stages, it would be necessary to carefully investigate the specific and unique functions of TGF-β. It is also important to pay particular attentions to signaling pathways elicited by TGF-β. Not only because these pathways include canonical and noncanonical ones, but also because they crosstalk with other signaling pathways to generate new functional outcomes, which can lead to highly variable biological effects.
