Secretory products from epicardial adipose tissue induce adverse myocardial remodeling after myocardial infarction by promoting reactive oxygen species accumulation

Adverse myocardial remodeling, manifesting pathologically as myocardial hypertrophy and fibrosis, often follows myocardial infarction (MI) and results in cardiac dysfunction. In this study, an obvious epicardial adipose tissue (EAT) was observed in the rat model of MI and the EAT weights were positively correlated with cardiomyocyte size and myocardial fibrosis areas in the MI 2- and 4-week groups. Then, rat cardiomyocyte cell line H9C2 and primary rat cardiac fibroblasts were cultured in conditioned media generated from EAT of rats in the MI 4-week group (EAT-CM). Functionally, EAT-CM enlarged the cell surface area of H9C2 cells and reinforced cardiac fibroblast activation into myofibroblasts by elevating intracellular reactive oxygen species (ROS) levels. Mechanistically, miR-134-5p was upregulated by EAT-CM in both H9C2 cells and primary rat cardiac fibroblasts. miR-134-5p knockdown promoted histone H3K14 acetylation of manganese superoxide dismutase and catalase by upregulating lysine acetyltransferase 7 expression, thereby decreasing ROS level. An in vivo study showed that miR-134-5p knockdown limited adverse myocardial remodeling in the rat model of MI, manifesting as alleviation of cardiomyocyte hypertrophy and fibrosis. In general, our study clarified a new pathological mechanism involving an EAT/miRNA axis that explains the adverse myocardial remodeling occurring after MI.Subject terms: Cell biology, Molecular biology     

Antioxidants and unsaturated fatty acids are involved in salt tolerance in peanut

To explore the possible physiological mechanism of salt tolerance in peanut, we investigated the effect of salinity on antioxidant enzyme activity, fatty acid composition, and chlorophyll fluorescence parameters. Seedlings at the initial growth stage had been treated with 0, 100, 150, 200, 250, and 300 mM NaCl for 7 days. Results showed that fresh mass and dry mass decreased with the rise of the NaCl concentration. They decreased significantly when the NaCl concentration was more than 200 mM. The PSII’s highest photochemical efficiency (F _v/F _m) was not affected before treating 250 mM NaCl. However, the PSII (ΦPSII)’s actual photochemical efficiency of decreased after treating 200 mM NaCl. Both the initial fluorescence (F _o) and non-photochemical quenching (NPQ) increased after 200 mM NaCl treatment. PSI oxidoreductive activity (ΔI/I _o) was not affected before 200 mM NaCl. The malondialdehyde (MDA) content increased with the rise of the NaCl concentration. The activities of ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities increased first and then decreased, while the content of H₂O₂ and O ₂ ^?· decreased first and then increased. Treated with 150 mM NaCl, the linolenic acid (18:3) and linoleic acid (18:2) of monogalactosyldiacylglycerols (MGDG), digalactosyldiacylglycerols (DGDG), sulphoquinovosyldiacylglycerols (SQDG) as well as phosphatidylglycerols (PG), the ratio of DGDG/MGDG increased, and the opposite results were obtained with 300 mM NaCl. The double bond index (DBI) of MGDG, DGDG, SQDG, and PG also increased after treating 150 mM NaCl. These conclusions verified that increased unsaturated fatty acid content in membrane lipid of peanut leaves could improve salt tolerance by alleviating photoinhibition of PSII and PSI.     

利用离体诱变培育花生新品种宇花4号

为了丰富花生遗传资源,开拓新的育种方法,本研究对离体诱变创造花生新种质、培育花生新品种进行了研究。利用花生品种花育20号胚小叶作为外植体,平阳霉素(PYM)作为诱变剂进行离体诱变培养,然后在含有羟脯氨酸(HYP)的培养基上进行定向筛选,最终获得了15个再生小苗。再生小苗经嫁接移栽田间,从后代中获得了23个高油株系,3个产量显著提高的品系,其中一个高产高油品系2015年通过了安徽省新品种登记鉴定,定名为宇花4号,在参试的品种中名列第一,比对照白沙1016增产16.63%。宇花4号为早熟、小粒、高油花生品种,经农业部油料及制品质量监督检验测试中心(武汉)化验,籽仁含油率达56.10%,达到高油标准,比诱变亲本花育20号(含油率49.50%)高6.6个百分点,荚果产量比花育20号增产15%以上。本研究结果表明,离体诱变结合离体定向筛选是创造花生新种质、培育新品种的有效途径。     

Influence of spatial arrangement in maize-soybean intercropping on root growth and water use efficiency

Background and aims

The relationship between transpiration and root distribution under different spatial arrangements of intercropping is poorly understood. The effects of three spatial arrangements in the maize (Zea mays L.) - soybean (Glycine max L.) intercropping on root distribution, transpiration, water use efficiency (WUE) and grain yield were examined.

Methods

Two-year field experiments were conducted using three spatial arrangements of 2 rows maize × 4 rows soybean (M2S4), 2 rows maize × 2 rows soybean (M2S2) and 4 rows maize × 2 rows soybean (M4S2), with their respective sole crops (monocrop) for comparison.

Results

The grain yield of maize in intercrops was higher than its monocrop and that of soybean in intercrops was lower than its monocrop. Except for M2S2 in 2014, there were yield advantages in intercropping due to improvement in the land use efficiency. Transpiration in maize was higher than in soybean regardless of the spatial arrangements. Transpiration of both maize and soybean was influenced by the spatial arrangements of the intercropping with M4S2 or M2S4 tending to have higher daily transpiration than monocrops and other spatial arrangements. Intercropping enhanced root length density (RLD) in both maize and soybean compared to the corresponding monocrop. RLD was higher and land equivalent ratio (LER) was lower under M2S2 than under other spatial arrangements of intercropping, WUE was higher in M4S2 than in other spatial arrangements.

Conclusions

Intercropping was more efficient in using the environmental resources than monocropping. The M4S2 spatial arrangement in the maize-soybean intercropping could be selected because of its sustainability and greater land and water use efficiency.

     

Establishment of immortalized mouse intestinal epithelial cells line and study of effects of Arg-Arg on inflammatory response

Primary mouse intestinal epithelial cells (MIEs) are not ideal models for long-term culture in vitro and a limited amount of approximate three generations. In addition, the mechanism that arginine-arginine dipeptide (Arg-Arg) regulates mouse intestinal inflammatory response remains unknown. Therefore, the aim of this study was to establish immortal MIEs and study the effects of Arg-Arg on inflammatory response after challenging the MIEs with lipopolysaccharide (LPS) or staphylococcal enterotoxin C (rSEC). Our data showed that immortalized MIEs could be cultured over 100 generations. The immortalized MIEs showed positive reaction against cytokeratine 18 antigen, E-cadherin, and peptide transporters (Pept1) using indirect immunofluorescence. Cytokeratine 18 and Pept1 can be expressed in immortalized MIEs by immunoblotting. Fatty acid-binding proteins (FABPs) and villin known as intestinal epithelial cell functional protein were constitutively expressed in immortalized MIEs. For inflammatory response, these results showed that Arg-Arg can decrease the LPS-induced expression of IL-1β and the rSEC-induced expression of TNF-α; however, it can upregulate the LPS-induced expression of IL-6 and TNF-α and the rSEC-induced expression level of IL-1β. In addition, in the MAPK signaling pathway, pSAPK/JNK and p-Erk1/2 in LPS with Arg-Arg treatment were upregulated than that in LPS treatment. p-p38 in LPS with Arg-Arg treatment was attenuated than that in LPS treatment. pSAPK/JNK and p-p38 in rSEC with Arg-Arg treatment were enhanced than that in rSEC treatment. Conversely, p-Erk1/2 in rSEC with Arg-Arg treatment was attenuated than that in rSEC treatment. These novel findings suggest that Arg-Arg dipeptide plays an important role for regulation of the immunologic balance in mouse intestinal inflammatory response.     

Accurate analysis of fusion expression of <Emphasis Type="Italic">Pichia pastoris</Emphasis> glycosylphosphatidylinositol-modified cell wall proteins

Glycosylphosphatidylinositol (GPI)-anchored glycoproteins have diverse intrinsic functions in yeasts, and they also have different uses in vitro. The GPI-modified cell wall proteins GCW21, GCW51, and GCW61 of Pichia pastoris were chosen as anchoring proteins to construct co-expression strains in P. pastoris GS115. The hydrolytic activity and the amount of Candida antarctica lipase B (CALB) displayed on cell surface increased significantly following optimization of the fusion gene dosage and combination of the homogeneous or heterogeneous cell wall proteins. Maximum CALB hydrolytic activity was achieved at 4920 U/g dry cell weight in strain GS115/CALB-GCW (51 + 51 + 61 + 61) after 120 h of methanol induction. Changes in structural morphology and the properties of the cell surfaces caused by co-expression of fusion proteins were observed by transmission electron microscopy (TEM) and on plates containing cell-wall-destabilizing reagent. Our results suggested that both the outer and inner cell layers were significantly altered by overexpression of GPI-modified cell wall proteins. Interestingly, quantitative analysis of the inner layer components showed an increase in β-1,3-glucan, but no obvious changes in chitin in the strains overexpressing GPI-modified cell wall proteins.     

Effects of exogenous abscisic acid (ABA) on cucumber seedling leaf carbohydrate metabolism under low temperature

Seedlings with four true leaves of cucumbers (Cucumis sativus L.), Guonong No.25 (a cold-tolerant cultivar) and Guonong No.41 (a cold sensitive cultivar), were grown under normal or low temperature conditions: 25°C/18°C or 15°C/8°C (day/night). The seedlings of Guonong No.25 under low temperature were also treated with or without exogenous ABA. The purpose of our study was to find out the effects of low temperature and exogenous ABA application on the carbohydrate metabolism in the cucumber plants. Time course changes of carbohydrate contents and activities of stachyose synthase and alkaline α-galactosidase in the seedling leaves were investigated after the treatment. Our results show that compared to the seedlings under temperatures of 25°C/18°C, the seedlings of the both tested genotypes under 15°C/8°C (day/night) have significantly higher contents of all measured soluble carbohydrates. Significant difference in stachyose synthase activity is observed between the two genotypes under normal temperature or low temperature. Under normal temperature, leaf stachyose synthase activity in Guonong No.41 is higher than that in Guonong No.25. The stachyose synthase activity of Guonong No.41 decreases sharply under low temperature, but that of Guonong No.25 increases 3 days after treatment and then decreases to the original level. In contrast, there is no significant genotypic difference in alkaline α-galactosidase activity. Additionally, compared to the control seedlings treated with 0 μM ABA, the seedlings treated with 50 and 150 μM ABA accumulate substantial amounts of all tested soluble carbohydrates except galactose whereas 250 μM ABA treated seedlings show decreased levels of all these soluble carbohydrates. Stachyose synthase activity increases significantly upon 50 and 150 μM ABA treatments. Fan-zhen Menga, Li-ping Hu, and Shao-hui Wang contributed equally to the paper.     

千年桐SAD基因克隆与分析及其丝状真菌表达载体构建

以发育中的千年桐种子总RNA为模板,通过RT-PCR方法扩增得到硬脂酰脱饱和酶基因SAD的cDNA序列。该序列长度为1 191 bp,编码396个氨基酸。推测的分子量为45 541.01 u,等电点pI为6.05。BLAST分析表明,该cDNA序列与其它已登录的SAD基因cDNA序列一致性最高可达93.1%;编码的氨基酸蛋白序列性一致最高为89%。同时,构建了由构巢曲霉3-磷酸甘油醛脱氢酶基因的gpdA启动子驱动的丝状真菌表达载体,通过冻融法转入农杆菌中,PCR鉴定表明,pBAR-SAD已转入农杆菌EHA105中,成功构建了农杆菌工程菌株。