Institute of Hydrobiology, Chinese Academy Of Sciences
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长江干流宜昌-监利段洲滩湿生植物群落特征及其驱动因子分析
No full text为了解长江干流洲滩湿地植物的群落结构特征及其驱动因子,于2018年3 ~ 5月对干流宜昌-监利5个江段洲滩的湿生植物开展了调查。共采集湿生植物88种,隶属于26科73属,其中菊科( Compositae) 、禾本科( Gramineae) 、蓼科( Polygonaceae)占优势,狗牙根、薹草、牛鞭草、虉草为主要优势种。采集样方平均种类数为6种,平均密度为88.9 ind /m~2,平均生物量(地上部分干重)为55.8 g /m~2。采集洲滩湿生植物群落结构时空差异较大。枝城江段洲滩样方物种数、密度和生物量均为最大,荆州洲滩均最小。样方密度在3 ~ 5月间呈下降趋势,生物量则呈上升趋势。划分了薹草、狗牙根、牛鞭草-紫菀等10个稳定群落。典范对应分析表明湿生植物群落组成主要受到黏粒比例、相对水面高程、土壤含水率以及土壤总有机质含量的影响,其中影响最大的是黏粒比例。样方总生物量沿相对水面高程、总有机质、土壤含水率的变化趋势一致,即先增大后减小;而与黏粒含量的关系不明显。分析认为洲滩湿生植物分布格局是在水文过程影响下,由底质、水分及营养共同作用的结果
Structural and Functional Insights into a Lysine Deacylase in the Cyanobacterium Synechococcus sp. PCC 7002
No full textLys deacylases are essential regulators of cell biology in many contexts. Here, we have identified CddA (cyanobacterial deacetylase/depropionylase), a Lys deacylase enzyme expressed in the cyanobacterium Synechococcus sp. PCC 7002 that has both deacetylase and depropionylase activity. Loss of the gene cddA led to slower growth and impaired linear and cyclic photosynthetic electron transfer. We determined the crystal structure of this depropionylase/deacetylase at 2.1 angstrom resolution and established that it has a unique and characteristically folded alpha/beta structure. We detected an acyl binding site within CddA via site-directed mutagenesis and demonstrated that this site is essential for the deproprionylase activity of this enzyme. Through a proteomic approach, we identified a total of 598 Lys residues across 382 proteins that were capable of undergoing propionylation. These propionylated proteins were highly enriched for photosynthetic and metabolic functionality. We additionally demonstrated that CddA was capable of catalyzing in vivo and in vitro Lys depropionylation and deacetylation of Fru-1,6-bisphosphatase, thereby regulating its enzymatic activity. Our identification of a Lys deacylase provides insight into the mechanisms globally regulating photosynthesis and carbon metabolism in cyanobacteria and potentially in other photosynthetic organisms as well
Investigation of an Antioxidative System for Salinity Tolerance in Oenanthe javanica
No full textAbiotic stress, such as drought and salinity, severely affect the growth and yield of many plants. Oenanthe javanica (commonly known as water dropwort) is an important vegetable that is grown in the saline-alkali soils of East Asia, where salinity is the limiting environmental factor. To study the defense mechanism of salt stress responses in water dropwort, we studied two water dropwort cultivars, V11E0022 and V11E0135, based on phenotypic and physiological indexes. We found that V11E0022 were tolerant to salt stress, as a result of good antioxidant defense system in the form of osmolyte (proline), antioxidants (polyphenols and flavonoids), and antioxidant enzymes (APX and CAT), which provided novel insights for salt-tolerant mechanisms. Then, a comparative transcriptomic analysis was conducted, and Gene Ontology (GO) analysis revealed that differentially expressed genes (DEGs) involved in the carbohydrate metabolic process could reduce oxidative stress and enhance energy production that can help in adaptation against salt stress. Similarly, lipid metabolic processes can also enhance tolerance against salt stress by reducing the transpiration rate, H2O2, and oxidative stress. Furthermore, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that DEGs involved in hormone signals transduction pathway promoted the activities of antioxidant enzymes and reduced oxidative stress; likewise, arginine and proline metabolism, and flavonoid pathways also stimulated the biosynthesis of proline and flavonoids, respectively, in response to salt stress. Moreover, transcription factors (TFs) were also identified, which play an important role in salt stress tolerance of water dropwort. The finding of this study will be helpful for crop improvement under salt stress
Coupling between Benthic Nutrient Cycling and Pelagic Phytoplankton Community in Taiwan Strait in Spring 2018
No full textAlthough the nutrient as a driving force for the red tide was intensively studied, the spatial patterns of the phytoplankton community and its response to benthic nutrient cycling remain unclear. We determined the pelagic phytoplankton community and its extracellular alkaline phosphatase qualitatively using enzyme-labeled fluorescence (ELF) technique, concomitantly with the concentrations of phosphorus (P) and nitrogen (N) in the water and sediments in the Taiwan Strait in spring 2018. A total of 30 phytoplankton genera were identified with a higher abundance of the abundance of Prorocentrum and Trichodesmium being observed at the north coast and the center of the southern strait, respectively. Both phytoplankton abundances and Trichodesmium were negatively correlated with the ratios of dissolved inorganic N and ammonium to soluble reactive P (DIN/SRP, NH4+/SRP) in the bottom. Furthermore, the ELF-labeling percentage in Trichodesmium was negatively correlated with total P and SRP but positively correlated with TN/TP, DIN/SRP, and NH4+/SRP in the bottom. In contrast to high DIN/SRP of the surface, lower DIN/SRP in the bottom was owing to a high P release potential and weak sequestration of P as evidenced by the distribution of P solubilizing bacteria and P content. Our findings indicated that the benthic nutrient regime might shape the structure of the pelagic phytoplankton community
Comparative transcriptome analysis of scaled and scaleless skins in Gymnocypris eckloni provides insights into the molecular mechanism of scale degeneration
No full textAbstractBackgroundThe scale degeneration is thought to be related to the adaptation to the extreme environment with cold climate and high-altitude in schizothoracine fishes. Gymnocypris eckloni, a schizothoracine fish living in plateau waters with the elevation above 2500?m, is nearly esquamate and only covered with shoulder scales and anal scales, making it a good model species to study the molecular mechanism of scale degeneration.ResultsThe transcriptomes of shoulder scaled skins (SSS), anal scaled skins (ASS) and scaleless skins (NSS) were sequenced and analyzed in G. eckloni at the age of 1 year. Histological examination showed that shoulder scale had completed its differentiation and anal scale just initiated the differentiation. A total of 578,046 unigenes were obtained from the transcriptomes, with 407,799 unigenes annotated in public databases. A total of 428 and 142 differentially expressed unigenes (DEUs) were identified between SSS and NSS, and between ASS and NSS, respectively, with 45 DEUs that were overlapped. Annotation analysis indicated that these DEUs were mainly enriched in Gene Ontology (GO) terms and KEGG pathways associated with bone and muscle formation, such as myofibril, contractile fiber, cytoskeletal protein binding, muscle structure development, cardiac muscle contraction, hypertrophic cardiomyopathy (HCM) and calcium signaling pathway.ConclusionsOur results would provide insights into the molecular mechanisms of scale degeneration in G. eckloni and other congeneric fishes. In addition, the transcriptome data provides candidate genes and markers for future studies
Effects of a Type I RM System on Gene Expression and Glycogen Catabolism inSynechocystissp. PCC 6803
No full textIncreasing evidence has shown that DNA methylation is involved in gene regulation in prokaryotes. However, there have been very limited reports about the role of DNA methylation in regulation of gene expression and physiological functions in cyanobacteria. InSynechocystissp. PCC 6803, four genes on the plasmid pSYSX are predicted to encode the type I restriction-methylation system,slr6095andslr6096for the M subunit,slr6097for the S subunit andslr6102for theRsubunit. Compared to the wild type,slr6095,slr6096, andslr6097mutants lacked the GG(m6)AN(7)TTGG/CCA(m6)AN(7)TCC methylation in genomic DNA. Transcriptomic analysis indicated that 171 genes were reproducibly up- or down-regulated in all three mutants relative to the wild type. The changed expression of some genes, includingsll1356for glycogen phosphorylase (GlgP), was associated with the loss of GG(m6)AN(7)TTGG/CCA(m6)AN(7)TCC methylation in the coding regions or the upstream non-coding sequences. Inactivation ofslr6095,slr6096, orslr6097increased the expression ofsll1356and the GlgP activity but lowered the glycogen content. These results indicated that the DNA methylation by a type I RM system could alter the expression of certain genes and physiological functions inSynechocystissp. PCC 6803
ADNP promotes neural differentiation by modulating Wnt/beta-catenin signaling
No full textADNP (Activity Dependent Neuroprotective Protein) is a neuroprotective protein whose aberrant expression has been frequently linked to neural developmental disorders, including the Helsmoortel-Van der Aa syndrome (also called the ADNP syndrome). However, its role in neural development and pathology remains unclear. Here, we show that ADNP is required for neural induction and differentiation by enhancing Wnt signaling. Mechanistically, ADNP functions to stabilize beta -Catenin through binding to its armadillo domain which prevents its association with key components of the degradation complex: Axin and APC. Loss of ADNP promotes the formation of the degradation complex and beta -Catenin degradation via ubiquitin-proteasome pathway, resulting in down-regulation of key neuroectoderm developmental genes. In addition, adnp gene disruption in zebrafish leads to defective neurogenesis and reduced Wnt signaling. Our work provides important insights into the role of ADNP in neural development and the pathology of the Helsmoortel-Van der Aa syndrome caused by ADNP gene mutation. ADNP has been connected to neural developmental disorders. Here, the authors uncover a role for ADNP in neural induction and differentiation via beta -Catenin stabilization, with ADNP disruption in zebrafish leading to defective neurogenesis and decreased Wnt signaling
Natural adsorption of methylene blue by waste fallen leaves of Magnoliaceae and its repeated thermal regeneration for reuse
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