Pseudomonas oryzae sp. nov. isolated from a paddy soil in South China

A Gram-staining-negative, rod-shaped and motile with several polar flagellums bacterium, designated WM-3^T, was isolated from a rice paddy soil in South China. Growth occurred with 0–3.0 % (w/v) NaCl (optimum 2.0 %), at pH 5.5–9.0 (optimum pH 7.0) and at 25–42 °C (optimum 30–37 °C) in liquid Reasoner’s 2A medium. Analysis of the 16S rRNA gene and gyrB gene sequences revealed that strain WM-3^T was most closely related to the type strains of the species Pseudomonas linyingensis and Pseudomonas sagittaria. Its sequence similarities with P. linyingensis CGMCC 1.10701^T and P. sagittaria JCM 18195^T were 97.4 and 97.3 %, respectively, for 16S rRNA gene, and were 94.1 and 94.2 %, respectively, for gyrB gene. DNA–DNA hybridization between strain WM-3^T and these two type strains showed relatedness of 35.6 and 30.9 %, respectively. G+C content of genomic DNA was 69.4 mol%. The whole-cell fatty acids mainly consisted of C_16:0 (30.0 %), C_16:1 ω6c and/or C_16:1 ω7c (19.3 %) and C_18:1 ω6c and/or C_18:1 ω7c (16.3 %). The results of phenotypic, chemotaxonomic and genotypic analyses clearly indicated that strain WM-3^T belongs to genus Pseudomonas but represents a novel species, for which the name Pseudomonas oryzae sp. nov. is proposed. The type strain is WM-3^T (=KCTC 32247^T =CGMCC 1.12417^T).     

Role of the sonchus yellow net virus N protein in formation of nuclear viroplasms

Sonchus yellow net virus is a plant nucleorhabdovirus whose nucleocapsid (N), phosphoprotein (P), and polymerase (L) proteins form large viroplasms in the nuclei of infected plants (C. R. F. Martins, J. A. Johnson, D. M. Lawrence, T. J. Choi, A. Pisi, S. L. Tobin, D. Lapidus, J. D. O. Wagner, S. Ruzin, K. McDonald, and A. O. Jackson, J. Virol. 72:5669-5679, 1998). When expressed alone, the N protein localizes to the nuclei of plant and yeast (Saccharomyces cerevisiae) cells and the P protein is distributed throughout the cells, but coexpression of N and P results in formation of subnuclear viroplasm-like foci (M. M. Goodin, J. Austin, R. Tobias, M. Fujita, C. Morales, and A. O. Jackson, J. Virol. 75:9393-9406, 2001; M. M. Goodin, R. G. Dietzgen, D. Schichnes, S. Ruzin, and A. O. Jackson, Plant J. 31:375-383, 2002). We now show that the N protein and various fluorescent derivatives form similar subnuclear foci in plant cells and that homologous interactions mediated by a helix-loop-helix region near the amino terminus are required for formation of the foci. Mutations within the helix-loop-helix region also interfere with N- and P-protein interactions that are required for N and P colocalization in the subnuclear foci. Affinity purification of N proteins harboring single mutations within the motif revealed that Tyr40 is critical for N-N and N-P interactions. Additional in vitro binding assays also indicated that the N protein binds to yeast and plant importin alpha homologues, whereas mutations in the carboxy-terminal nuclear localization signal abrogate importin alpha binding. The P protein did not bind to the importin alpha homologues, suggesting that the N and P proteins use different pathways for nuclear entry. Our results in toto support a model suggesting that during infection, the N and P proteins enter the nucleus independently, that viroplasm formation requires homologous N-protein interactions, and that P protein targeting to the viroplasm requires N-P protein interactions that occur after N and P protein import into the nucleus.     

水生昆虫对汞的吸收、富集和水-陆转移

汞是一种人体非必需且有毒的重金属元素,全球性的汞污染因对人类健康具有损害而备受社会关注。自然界中的汞绝大部分会通过江河径流和雨雪尘土的沉降而进入水生生态系统,每年进入水生生态系统的汞至少有10 000吨。水生昆虫作为重要的消费者生物存在于水生生态食物网中,是其重要的组成部分,在水生生态系统的物质循环中扮演着重要角色。本文介绍了近年来水生昆虫与汞之间的相关研究,重点总结了水生昆虫对汞的吸收和富集程度,分析了水生昆虫在汞的水-陆转移中的作用。研究数据表明,水生昆虫对汞的吸收程度与环境因素有关,并通过不同的途径转移到陆地生态系统中,对陆地生态系统上层食物链的生物存在一定的威胁,同时也需注意在对水生昆虫进行开发利用的同时,考虑汞是否超标的因素。     

热带－亚热带森林中猕猴的食性

采用跟踪观察法对热带－亚热带森林中的猕猴种群的食性及其与植被类型的关系进行了调查,结果表明,猕猴主要选择季雨林或次生季雨林为其觅食场所,栖息地植物的地理分布和种类直接影响其食性,猕猴对植物各部位的采食频度随植物生长期而变化．     

喀斯特地区坡耕地与退耕地土壤有机碳空间异质性及其影响因素

利用网格采样(10 m×10 m),对比分析了典型喀斯特坡耕地(长期耕作)和退耕地(自然恢复)表层(0—15 cm)土壤有机碳(SOC)的空间变异特征,以期探究退耕恢复20a后SOC的空间异质性及其主要影响因素的变化。结果表明退耕地SOC含量(75.5 g/kg)显著高于坡耕地(15.1 g/kg),为坡耕地的5.0倍,说明自然恢复能显著提高SOC累积量;半变异函数分析结果表明退耕地基台值(521.7)为坡耕地(25.7)的14.9倍,说明退耕地SOC空间异质性远大于坡耕地。坡耕地和退耕地SOC的主要影响因子存在较大差异,土地覆盖类型、坡位、岩石出露率以及三者的交互作用显著控制着坡耕地SOC的空间格局,其贡献率分别为9.1%、6.3%、4.6%以及17.0%;土壤水分、坡度、岩石出露率以及三者的交互作用显著控制退耕地SOC的空间格局,其贡献率分别为26.0%、10.7%、7.2%以及3.6%;尽管岩石出露率对坡耕地和退耕地SOC的空间格局均有显著影响,但坡耕地SOC的主要控制因子为土地覆盖类型以及各因子的交互作用,而退耕地的主要控制因子为土壤水分。以上研究表明随着植被恢复和物种多样性增加,喀斯特坡地SOC的累积量和空间异质性增强,自然因素对SOC空间格局影响凸显,而岩石出露率始终控制SOC空间格局。     

Tsp2 Facilitates Tumor-associated Fibroblasts Formation and Promotes Tumor Progression in Retroperitoneal Liposarcoma

Retroperitoneal liposarcoma (RLPS) is the most common subtype of retroperitoneal soft tissue sarcoma, characterized by a high recurrence rate and insensitivity to radiotherapy and chemotherapy. The function of tumor microenvironmental components, especially tumor-associated fibroblasts (TAFs), remains unclear in RLPS. The crosstalk between tumor cells and stromal cells should be clarified for therapy target discovery in RLPS. In this study, we demonstrated that TAFs from dedifferentiated liposarcoma (DDLPS) could attract LPS cells and promote their proliferation and migration. However, although α-SMA is positively expressed in RLPS, its expression does not indicate prognosis. By screening differentially expressed genes, performing Oncomine visualization, TCGA gene expression correlation analysis and qPCR verification, we determined that thrombospondin-2 (THBS2) gene expression was related to TAFs. The expression of Tsp2 protein, which was encoded by THBS2, was correlated with α-SMA expression, and it was an independent predictive factor for disease-free survival and recurrence-free survival in patients with RLPS. In vitro, Tsp2 facilitated the transformation of bone marrow-derived fibroblasts (BMFs) to TAFs and promoted the malignant biological behaviors of LPS cells by activating the MAPK/MEK/ERK pathway. Therefore, suppression of Tsp2 is expected to be a promising treatment method for RLPS patients.     

Phylogenetic relationships of Cyrtandromoea and Wightia revisited: A new tribe in Phrymaceae and a new family in Lamiales

The familial placements of Cyrtandromoea Zoll. and Wightia Wall., two small and enigmatic South‐East Asian genera, have long been controversial in Lamiales. Here we adopt a two‐step approach to resolve their phylogenetic relationships. We initially reconstructed a large‐scale phylogeny of Lamiales using six chloroplast markers (atpB, matK, ndhF, psbBTNH, rbcL, and rps4). The results showed that both Cyrtandromoea and Wightia emerged in the LMPO clade, including Lamiaceae, Mazaceae, Phrymaceae, Paulowniaceae, and Orobanchaceae. Based on the second set of six chloroplast markers (atpB, matK, ndhF, rbcL, rps16, and trnL‐F) and two nuclear ribosomal regions (external transcribed spacer and internal transcribed spacer) for the analyses focusing on the LMPO clade, our results revealed that Cyrtandromoea was consistently nested within Phrymaceae, whereas Wightia was supported as sister to Phrymaceae by the chloroplast DNA dataset or sister to Paulowniaceae by the nuclear ribosomal DNA dataset. Morphological and anatomical evidence fully supports the inclusion of Cyrtandromoea in Phrymaceae, and an updated tribal classification is done for Phrymaceae with five tribes, that is, Cyrtandromoeeae Bo Li, Bing Liu, Su Liu & Y. H. Tan, trib. nov., Diplaceae Bo Li, Bing Liu, Su Liu & Y. H. Tan, trib. nov., Leucocarpeae, Mimuleae, and Phrymeae. The conflicting phylogenetic position of Wightia indicated by different genome markers results in difficulty placing the genus in either Phrymaceae or Paulowniaceae. Considering the distinct morphological differences between Wightia and other families in the LMPO clade, we here propose a new family, Wightiaceae Bo Li, Bing Liu, Su Liu & Y. H. Tan, fam. nov., to accommodate it, which is the 26th family recognized in Lamiales.     

PSII-efficiency,polysaccharide production,and phenotypic plasticity of Scenedesmus obliquus in response to changes in metabolic carbon flux

To investigate the response of Scenedesmus obliquus to changes in metabolic carbon flux, S. obliquus was cultured in medium with different concentrations of glyoxylate over 9 days. Results showed that growth rates were not affected in the lower concentration glyoxylate (0.25 and 0.5 mM). However, growth rate of S. obliquus was inhibited in the higher concentration glyoxylate (0.85 and 1.25 mM) during the early phase before recovering at higher densities. Changes in growth rates in different glyoxylate concentrations were in line with changes in F_v/F_m and Φ_PSII. Colony formation was observed in S. obliquus in the four glyoxylate treatments. As a consequence, the mean number of cells per particle of S. obliquus in the glyoxylate treatments were significantly higher than those in the control. The total polysaccharide content of S. obliquus cells increased with increased glyoxylate concentrations. The increased glyoxylate-stimulated polysaccharide levels were directly correlated with colony size of S. obliquus.