Institutional Repository of South China Sea Institute of Oceanology, CAS
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熊本牡蛎多嵴和无嵴品系F_3生长性状的连续选择效应
No full text为进一步检测熊本牡蛎(Crassostrea sikamea)多嵴和无嵴品系F3的连续选择反应,以2个品系F2上选组为材料,开展2个品系F3混合上选研究,评估2个品系F3生长性状的选择反应、现实遗传力及遗传改进量,解析选育过程中选择效应、品系效应及二者交互作用对生产性状的影响。结果表明:多嵴品系F3生长性状具有较高的现实遗传力,表现出较好的遗传改良效果;无嵴品系F3表现出中等现实遗传力水平,但仍具有一定程度的遗传改良潜能。养成期360日龄时,多嵴品系子代壳高、鲜重的选择反应分别为0.70、0.76;现实遗传力分别为0.40、0.43;遗传改进量分别为7.02%、12.29%;无嵴品系的选择反应分别为0.36、0.33;现实遗传力分别为0.20、0.19;遗传改进量分别为3.74%、5.72%。经过双因子分析模型检测发现:品系来源是影响F3生长性状的主要因子,选择效应是次要因子,二者间不存在明显的交互作用。由此可见,随着连续选择的进行,选择反应逐渐降低,品系来源作用增强,本研究为熊本牡蛎遗传改良和新品系培育奠定了基础
长期高氨氮暴露对海水青鳉毒理效应的蛋白质组学研究
No full text氨氮是大多数硬骨鱼的氮代谢产物,但是环境中氨氮浓度过高也会对鱼类产生毒性作用。该研究结果显示,海水青鳉暴露于0.6和1.1mmol·L-1 NH4Cl 4周后的死亡率分别为21.25%和40%。这说明高浓度氨氮暴露对海水青鳉具有明显的毒性作用,而且暴露浓度越高,毒性越大。利用蛋白质组学的研究技术研究海水青鳉在长期氨氮暴露后的蛋白质响应变化,发现在0.6mmol·L-1 NH4Cl暴露条件下有16种蛋白的表达发生明显的变化,而在1.1mmol·L-1 NH4Cl暴露条件下有7种蛋白的表达发生明显的变化。这些蛋白主要参与氧化应激的产生,影响海水青鳉细胞结构组成、肌肉收缩、视觉通路、代谢调节和免疫调节,引起神经毒性。该研究利用蛋白质组学的研究方法研究了长期氨氮暴露对海水青鳉的毒理效应,为利用蛋白质组学探讨环境污染物的毒性效应提供了更深刻的认识
深海热液口Epsilon-变形菌的物种多样性与环境适应机理
No full textEpsilon-变形菌是近年来宏基因组调查发现的深海极端环境如热液喷口富集的重要微生物类群,在海洋碳、氮、氢、硫循环中发挥重要作用。目前对这个纲的研究较少,主要来自于16S rRNA的分类鉴定以及深度测序拼接的基因组序列分析。本文总结了目前对Epsilon-变形菌纲的生态分布及多样性调查研究结果,并对深海热液喷口的Epsilon-变形菌的多种能量代谢方式、强大的趋化运动系统以及与底栖生物的共生关系进行了阐述。这些结果初步揭示了Epsilon-变形菌对深海极端环境的适应机制,并推动对这个极端环境富集的细菌分支的生物学特征认知与资源利用
溶解有机物的光降解及其对浮游细菌和浮游植物的影响
No full text作为海洋中最大的动态有机碳储库,溶解有机物的光降解(主要是紫外波段)对生源要素的生物地球化学循环以及海洋生态系统的结构和功能具有重要的影响。本文探讨了影响溶解有机物光降解的环境因素、其光化学过程和产物,并重点阐述了溶解有机物的光降解对浮游细菌和浮游植物的影响。溶解有机物的来源和成分复杂,其光降解在不同海区有不同的生态效应,为了能更准确地把握其生态效应,需要更全面和深入的研究
New Furanone Derivatives and Alkaloids from the Co-Culture of Marine-Derived Fungi Aspergillus sclerotiorum and Penicillium citrinum
No full textSix new compounds including two furanone derivatives sclerotiorumins A and B (1 and 2), one novel oxadiazin derivative sclerotiorumin C (3), one pyrrole derivative 1-(4-benzyl-1H-pyrrol-3-yl)ethanone (4), and two complexes of neoaspergillic acid aluminiumneohydroxyaspergillin (5) and ferrineohydroxyaspergillin (6) were isolated from the co-culture of marine-derived fungi Aspergillus sclerotiorum and Penicillium citrinum. Compound 3 was the first natural 1,2,4-oxadiazin-6-one. Compound 5 showed significant and selective cytotoxicity against human histiocytic lymphoma U937 cell line (IC50=4.2 mu m) and strong toxicity towards brine shrimp (LC50=6.1 mu m), and oppositely increased the growth and biofilm formation of Staphylococcus aureus
Tail-Anchored Inner Membrane Protein ElaB Increases Resistance to Stress While Reducing Persistence in Escherichia coli
No full textHost-associated bacteria, such as Escherichia coli, often encounter various host-related stresses, such as nutritional deprivation, oxidative stress, and temperature shifts. There is growing interest in searching for small endogenous proteins that mediate stress responses. Here, we characterized the small C-tail-anchored inner membrane protein ElaB in E. coli. ElaB belongs to a class of tail-anchored inner membrane proteins with a C-terminal transmembrane domain but lacking an N-terminal signal sequence for membrane targeting. Proteins from this family have been shown to play vital roles, such as in membrane trafficking and apoptosis, in eukaryotes; however, their role in prokaryotes is largely unexplored. Here, we found that the transcription of elaB is induced in the stationary phase in E. coli and stationary-phase sigma factor RpoS regulates elaB transcription by binding to the promoter of elaB. Moreover, ElaB protects cells against oxidative stress and heat shock stress. However, unlike membrane peptide toxins TisB and GhoT, ElaB does not lead to cell death, and the deletion of elaB greatly increases persister cell formation. Therefore, we demonstrate that disruption of C-tail-anchored inner membrane proteins can reduce stress resistance; it can also lead to deleterious effects, such as increased persistence, in E. coli. IMPORTANCE Escherichia coli synthesizes dozens of poorly understood small membrane proteins containing a predicted transmembrane domain. In this study, we characterized the function of the C-tail-anchored inner membrane protein ElaB in E. coli. ElaB increases resistance to oxidative stress and heat stress, while inactivation of ElaB leads to high persister cell formation. We also demonstrated that the transcription of elaB is under the direct regulation of stationary-phase sigma factor RpoS. Thus, our study reveals that small inner membrane proteins may have important cellular roles during the stress response
Amino Acid Conjugated Anthraquinones from the Marine-Derived Fungus Penicillium sp SCSIO sof101
No full textEmodacidamides A H (1-8), natural products featuring anthraquinone amino acid conjugates, have been isolated from a marine-derived fungus, Penicillium sp. SCSIO sof101, together with known anthraquinones 9 and 10. The planar structures of 1-8 were elucidated using a combination of NMR spectroscopy and mass spectrometry. The absolute configurations of the amino acid residues were confirmed using Marfey's method and chiral-phase HPLC analyses. Additionally, isolates were evaluated for possible immunomodulatory and cytotoxic activities. Emodacidamides A (1), C (3), D (4), and E (5) cells with IC50 values of 4.1, 5.1, 12, and 5.4 mu M, respectively
Juvenile hormone and its receptor methoprene-tolerant promote ribosomal biogenesis and vitellogenesis in the Aedes aegypti mosquito
No full textJuvenile hormone (JH) controls many biological activities in insects, including development, metamorphosis, and reproduction. In the Aedes aegypti mosquito, a vector of dengue, yellow fever, chikungunya, and zika viruses, the metabolic tissue (the fat body, which is an analogue of the vertebrate liver) produces yolk proteins for developing oocytes. JH is important for the fat body to acquire competence for yolk protein production. However, the molecular mechanisms of how JH promotes mosquito reproduction are not completely understood. In this study we show that stimulation of the JH receptor methoprene-tolerant (Met) activates expression of genes encoding the regulator of ribosome synthesis 1 (RRS1) and six ribosomal proteins (two ribosomal large subunit proteins, two ribosomal small subunit proteins, and two mitochondrial ribosomal proteins). Moreover, RNAi-mediated depletion of RRS1 decreased biosynthesis of the ribosomal protein L32 (RpL32). Depletion of Met, RRS1, or RpL32 led to retardation of ovarian growth and reduced mosquito fecundity, which may at least in part have resulted from decreased vitellogenin protein production in the fat body. In summary, our results indicate that JH is critical for inducing the expression of ribosomal protein genes and demonstrate that RRS1 mediates the JH signal to enhance both ribosomal biogenesis and vitellogenesis
The Cyanobacteria-Dominated Sponge Dactylospongia elegans in the South China Sea: Prokaryotic Community and Metagenomic Insights
No full textThe South China Sea is a special reservoir of sponges of which prokaryotic communities are less studied. Here, a new record of the sponge Dactylospongia elegans is reported near the coast of Jinqing Island in the South China Sea, and its prokaryotic community is comprehensively investigated. Sponge specimens displayed lower microbial diversity compared with surrounding seawater. At the phylum level, prokaryotic communities were consistently dominated by Proteobacteria, followed by Cyanobacteria, Chloroflexi, Acidobacteria, Actinobacteria, Gemmatimonadetes, Thaumarchaeota, and Poribacteria. Operational taxonomic unit (OTU) analysis alternatively showed that the most abundant symbiont was the sponge-specific cyanobacterial species "Candidatus Synechococcus spongiarum," followed by OTUs belonging to the unidentified Chloroflexi and Acidobacteria. Phylogenetic tree based on 16S-23S internal transcribed spacer regions indicated that the dominated cyanobacterial OTU represented a new Glade of "Ca. Synechococcus spongiarum." More reliable metagenomic data further revealed that poribacterial symbionts were highly abundant and only secondary to the cyanobacterial symbiont. One draft genome for each of the Cyanobacteria, Chloroflexi and Acidobacteria and three poribacterial genomes were extracted from the metagenomes. Among them, genomes affiliated with the Chloroflexi and Acidobacteria were reported for the first time in sponge symbionts. Eukaryotic-like domains were found in all the binned genomes, indicating their potential symbiotic roles with the sponge host. The high quality of the six recovered genomes of sponge symbionts from the sponge D. elegans makes it possible to understand their symbiotic roles and interactions with the sponge host as well as among one another
The asymmetric distribution of phytoplankton in anticyclonic eddies in the western South China Sea
No full textAn anticyclonic eddy's periphery is characterized by large horizontal density gradients, strain and vertical velocity. In this paper we document the asymmetric distribution of phytoplankton around the periphery of anticyclonic eddies in the western South China Sea based on 432 eddies detected from satellite data. The high level of phytoplankton occurs consistently at the northwestern periphery of eddies, with a maximum positive chlorophyll anomaly greater than 0.01 mg m(-3). The asymmetric distribution of phytoplankton primarily tags the non-uniform surface velocity field varying from 0.15 m s(-1) to 0.3 m s(-1) along the eddy's periphery. The coastal boundary and off-coast jet may be the primary cause of the non-uniform flow. Associated with the non-uniform flow speed, the combined effects of the velocity convergence and steepened northwestern part of the eddies act to sharpen the density fronts and tend to result in an ageostrophic secondary circulation at the northwestern edge of the eddy. The upward component of the ageostrophic secondary circulation can enhance the nutrient flux into the euphotic layer, thereby increasing phytoplankton productivity. Anticyclonic eddy induced ageostrophic secondary circulation appears to be an important mechanism for increasing phytoplankton productivity in the oligotrophic waters of the South China Sea