土壤微生物生物地理学：国内进展与国际前沿

土壤微生物生物地理学是研究土壤中微生物空间分布格局及其随时间变化的一门科学,是土壤微生物学和微生物生态学等领域的研究前沿。近年来,尽管土壤微生物生物地理学研究取得了巨大进展,目前仍面临诸多难题与挑战。本文简要回顾了土壤微生物生物地理学的发展历程,重点介绍近年来我国在森林、草地和农田生态系统中土壤微生物生物地理学研究的主要进展。同时进一步阐述了目前土壤微生物生物地理学研究的国际前沿方向,包括微生物群落空间分布及其驱动机制、群落构建过程与共存网络、微生物地理分布与生态系统功能的关联以及预测微生物群落对全球变化的响应。最后,对土壤微生物生物地理学未来的研究方向进行了展望,强调了清晰的微生物物种定义、微生物群落的时间动态、多组学与合成生物学技术以及高精度的预测模型在土壤微生物生物地理学研究中的重要性。     

Effect of pidotimod on renal function and inflammatory response in rat IgA nephropathy model

AIM:To explore the effect of pidotimod on the renal function in IgA nephropathy (IgAN) rat model, and to further study whether this effect is related to the inhibition of inflammatory response. METHODS:The SD rats (n=36) were randomly divided into control group, IgAN model group, IgAN with prednisone treatment group and IgAN with pidotimod treatment group, with 9 rats in each group. The IgAN model was induced by consecutive oral administration of bovine gamma globulin (BGG) for 8 weeks followed by injection of BGG through tail vein for 3 d. After the IgAN model was established, the drug was continuously used for 4 weeks. At the end of the treatment, the urine protein, serum creatinine and blood urea nitrogen were examined by an automated analyzer. IgA deposition in the renal tissues was observed by immunofluorescence staining. The mRNA expression levels of renal fibrosis markers transforming growth factor-β1 (TGF-β1) and fibronectin 1 in the renal tissues were detected by RT-qPCR. The mRNA and protein levels of pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-6 in the renal tissues were determined by RT-qPCR and Western blot, respectively. RESULTS:No significant difference of the body weight was observed in different groups. Compared with control group, the content of urine protein, serum creatinine and blood urea nitrogen were significantly increased (P<0.01), whereas those were reversed by pidotimod treatment. The results of immunofluorescence staining showed that pidotimod inhibited IgA deposition in the IgAN rats. Pitomod treatment inhibited the mRNA expression levels of renal fibrosis markers TGF-β1 and fibronectin 1, and the mRNA and protein levels of pro-inflammatory cytokines IL-1β and IL-6 in the renal tissues of IgAN rats. CONCLUSION:Pidotimod alleviates IgAN progression in rats by inhibition of inflammatory response.     

Regulatory effect of astragaloside IV on SDF-1α/CXCR4 in EPCs

AIM: To investigate the effects of astragaloside IV (AS-IV) on chemokine receptor 4 (CXCR4) and stromal cell-derived factor 1α (SDF-1α) in endothelial progenitor cells (EPCs) and its mechanism. METHODS: Rat bone marrow-derived EPCs were cultured in vitro. The proliferation, adhesion, migration, apoptosis and tube formation capacity of EPCs treated with AS-IV and AMD3100, a specific blocker of CXCR4, were observed. The effects of AS-IV on the expression of SDF-1α/CXCR4 at mRNA and protein levels and the protein level of p-CXCR4 in the EPCs were determined. RESULTS: AS-IV significantly enhanced the proliferation, adhesion, migration and tube formation abilities of EPCs, reduced the apoptosis of EPCs, and up-regulated the mRNA and protein expression of SDF-1α and CXCR4 and the p-CXCR4 protein level in the EPCs. On the other hand, AMD3100 blocked the up-regulating effect of AS-IV on the mRNA and protein expression of CXCR4 and the p-CXCR4 protein level in the EPCs, but did not affect the effect of AS-IV on the expression of SDF-1α. CONCLUSION: AS-IV might enhance the biological function of EPCs by regulating the expression of SDF-1α/CXCR in EPCs.     

Development of colchicine‐induced tetraploid St. Augustinegrass (Stenotaphrum secundatum) lines

St. Augustinegrass is well suited for lawns and commercial landscapes. While many genotypes are cross‐fertile, all cultivars are propagated vegetatively in sod production. To ensure varietal purity, development of sterile triploid hybrids by crossing tetraploid and diploid genotypes has been successfully used in other warm‐season turfgrasses. Applying this model in St. Augustinegrass would be beneficial to sod producers and turf managers who require purity for certification and uniformity for performance, respectively. This study was conducted to develop colchicine‐induced tetraploid lines of St. Augustinegrass. Seeds of cultivar ‘Raleigh’ were treated with four colchicine concentrations at four exposure times. A non‐treated control was included among the treatments. Seedlings that germinated were screened for genome size changes using flow cytometry. Line DSA 13005 and two progeny lines derived through selfing, DSA 16001 and DSA 16016, were corroborated as tetraploids (2n = 4x = 36) through chromosome counts. These lines will be used in future breeding efforts to attempt development of sterile triploid cultivars of St. Augustinegrass.     

寄主植物中抑制十字花科黑腐病菌Ⅲ型分泌系统小分子化合物的鉴定

 寻找抑制植物病原菌III型分泌系统的植物源活性小分子化合物,是研发生物安全农药的重要途径之一。本研究采用水煮提取法从十字花科黑腐病菌寄主植物满身红萝卜中提取分离活性小分子化合物,利用高效液相-质谱联用解析出活性物质的单体结构。然后用荧光素酶基因luxAB构建融合报告系统以及定量PCR检测活性物质对十字花科黑腐病菌III型分泌系统的抑制效果,最后采用剪叶接种和压渗接种的方法研究活性小分子物质对十字花科黑腐病菌的生防作用。研究表明,植物鞘氨醇和二氢鞘氨醇对十字花科黑腐病菌III型分泌系统基因的转录表达有一定程度的抑制作用,但是对I、II、IV型分泌系统基因的表达没有明显的抑制作用。植物鞘氨醇在XCM1上影响菌的生长,而二氢鞘氨醇不影响菌的生长。同时,还发现这两种物质能显著降低Xcc在寄主植株满身红萝卜上的病害症状以及能够使Xcc在非寄主植物辣椒上引起过敏反应的能力丧失。该研究结果为深入研究小分子化合物对十字花科黑腐病菌III型分泌系统的作用机制及后续开发植物源抑制剂提供了一定的理论依据。     

混合盐胁迫对马蔺幼苗根系构型及生长量的影响

为探讨不同种类盐胁迫对马蔺幼苗生长状况的影响,采用室内培养的方法,研究总质量浓度为0.3%的NaCl、NaHCO₃单盐溶液及其不同配比的混合盐溶液胁迫对马蔺(Iris lactea var. chinensis)幼苗生长量、地上部干鲜重比值、地下部干鲜重比值以及根系构型的影响。结果表明,随着胁迫时间的延长,0.3%NaCl溶液对叶数和株高增长量的影响最小,其次为3种混合盐溶液,各处理在第14天时株高增幅达到最大。经0.3%NaHCO₃处理后的幼苗地上部干鲜重的比值为空白对照的2.17倍,地下部干鲜重则为空白对照的56.61%,随着混合溶液中NaHCO₃浓度的上升,地上部干鲜重比值表现出上升的趋势,地下部干鲜重比值则表现出下降的趋势。经35天处理后,0.3%NaHCO₃胁迫的马蔺幼苗根系总长、根系表面积较对照均显著下降,降幅分别为39.73%、26.08%,而各处理间的根系体积却无显著差异。研究结果显示,0.3%NaHCO₃溶液对马蔺幼苗的胁迫作用最强,2种单盐对根系的胁迫作用强于混合盐胁迫,而0.3%NaCl溶液对生长量的胁迫作用最弱。     

Effect of DNA methylation of miR-30a-5p promoter region on hepatic injury induced by homocysteine

AIM: To explore the role of DNA methylation of microRNA-30a-5p(miR-30a-5p) promoter region in hepatic injury. METHODS: Four-week-old normal mice and cystathionine β-synthase (CBS) single gene knockout mice were used and divided into normal (CBS^+/+, n=12) group and single gene knockout (CBS^+/-, n=12) group, and the mice were fed with high methionine diet for 8 weeks. HL-7702 hepatic cells were routinely cultured in vitro and divided into control group, homocysteine (Hcy) group and Hcy+5-azacytidne (AZC) group. Serum Hcy, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured by automatic biochemical analyzer. The levels of ALT and AST in the cells culture medium were determined by the microplate method. Hepatic injury in the mice were observed with HE staining. Cell viability staining was used to measure the viability of hepatocytes. RT-qPCR was used to detect the expression of miR-30a-5p in the liver tissues and hepatocytes. The correlation between the expression of miR-30a-5p and serum ALT and AST levels was analyzed by Pearson correlation analysis. DNA methylation level of miR-30a-5p promoter region in the liver tissues and hepatocytes was detected by nested landing methylation-specific PCR (nMS-PCR). RESULTS: Compared with the CBS^+/+ mice, the serum levels of Hcy, ALT and AST in the CBS^+/- mice were significantly increased (P < 0.05). HE staining showed the hepatocyte swelling and nuclear fragmentation and dissolution. The expression level of miR-30a-5p in the liver tissues was decreased (P < 0.01). Besides, the expression level of miR-30a-5p in the mice was negatively correlated with serum ALT and AST levels (r²=0.4557, P=0.0003, r²=0.4626, P=0.0003), and the DNA methylation of miR-30a-5p promoter region was increased (P < 0.01). In the HL-7702 cells, compared with control group,the ALT and AST levels were increased in Hcy group (P < 0.05, P < 0.01), and the cell viability was remarkablely decreased. DNA methylation of miR-30a-5p promoter region was increased (P < 0.01), which decreased after treated the cells with AZC (P < 0.05), while the expression level of miR-30a-5p in the cells was increased (P < 0.05). CONCLUSION: Hypermethylation of miR-30a-5p promoter region may play an important role in hepatic injury.     

栅藻B38营养成分分析及蛋白质营养价值评价

对栅藻B38的营养成分进行了全面分析,结果表明,栅藻藻粉中油脂含量14%,总糖含量13.86%,粗纤维3.52%,灰分4.28%,蛋白质49.0%,为高蛋白质类微藻。栅藻B38中含有23种脂肪酸。栅藻B38中氨基酸总量为852.58 mg/g,必需氨基酸占总氨基酸的47.45%,必需氨基酸指数为85.42%。两种模式的氨基酸比值系数分较接近,均在65以上;待评价物质的氨基酸品质与模式蛋白的贴近度接近1(0.93和0.88)。栅藻B38中共检测出23种矿物质元素,其中钠、钾、钙、镁、铁、铝含量较为丰富。重金属的含量均低于国家食品卫生标准。栅藻B38中维生素B3(106.02 mg/100 g)和维生素E(540.77 mg/100 g)的量较高。综上,栅藻B38的营养较丰富,可以进一步开发利用。     

羊角椒新品种寿研梦扬的选育

寿研梦扬是由母本CSVHPM1407001和父本CSVHPF1407002配制而成的羊角椒一代杂种。植株长势旺盛,连续坐果能力强;果实长羊角形,果长25～30 cm,果肩宽3～4 cm;青熟果黄绿色,老熟果红色;外表光亮,商品性好,耐贮运;单果质量100 g左右,辣味浓,宜鲜食;田间对病毒病、炭疽病和疫病的抗性强于对照喜洋洋。保护地栽培鲜椒产量可达12 840 kg·(667 m~2)~(-1)左右。适宜山东、河北等地区早春、秋延保护地种植。     

黑甜糯玉米新品种黑甜糯639的选育

黑甜糯639是以糯玉米自交系HNF为母本,以甜玉米自交系D91为父本配制而成的黑甜糯玉米一代杂种。生育期为91 d(天),株高263 cm,穗位151 cm,雄穗主轴与分枝角度中等,一级分枝18～23个,果穗筒型,籽粒黑紫色,甜糯籽粒比例为1∶3,籽粒可溶性糖含量为12.5%,支链淀粉占总淀粉含量的98.1%,口感佳。高抗丝黑穗病、茎腐病、大斑病,抗穗腐病和矮花叶病,平均每667 m~2鲜穗产量900 kg左右。适宜在山西省鲜食糯玉米主产区种植。