Microbiome structure and function in rhizosphere of Jerusalem artichoke grown in saline land.

The improvement and development of saline-alkali soils is currently a hot economic and scientific issue, and exploring the correlation between rhizosphere microorganisms of plants growing on saline-alkali soils and their salt tolerance has become the key point of related research. In our study, the community structure of microorganism and various properties of saline soils were characterized in which Jerusalem artichoke grown along a soil salinity gradient. A variety of basic soil properties were measured and the amplicon was performed as well as metagenomic sequencing on coastal saline soils using various techniques (such as RDA analysis and the assembly of genomes) to evaluate microbial functions. In addition, WGCNA (Weighted gene coexpression network analysis) method was used to identify the species related to salt stress and the sequence binning to assemble two enriched putative bacterial genomes. The research showed the cultivation of Jerusalem artichoke on saline soil changed soil physico-chemical and enzymatic properties; most of the rapidly changing as well as the long-term stable properties differed significantly between the rhizosphere and bulk soils. The amplicon and metagenomic sequencing revealed the function and structure of microorganisms varied between the rhizosphere and bulk soils, with greater microbial diversity in the rhizosphere. Catalase activity and the moisture content were the factors with the greatest impact on microorganisms. The putative genomes of two species of microorganisms (belong to Nitrospira and Gemmatimonas) were assembled, identified microbial species that were highly responsive to salt stress and that may play a key role in saline soil, stressed the important role of archaea in microbial communities in response to salt stress. The study provides a comprehensive understanding of the microbial community structure in the rhizosphere of Jerusalem artichoke to enable the improvement and economic development of saline land.

Inulin from Jerusalem artichoke tubers alleviates hyperglycaemia in high-fat-diet-induced diabetes mice through the intestinal microflora improvement.

The rate of hyperglycaemia in people around the world is increasing at an alarming rate at present, and innovative methods of alleviating hyperglycaemia are needed. The effects of Jerusalem artichoke inulin on hyperglycaemia, liver-related genes and the intestinal microbiota in mice fed a high-fat diet (HFD) and treated with streptozotocin (STZ) to induce hyperglycaemia were investigated. Inulin-treated hyperglycaemic mice had decreased average daily food consumption, body weight, average daily water consumption and relative liver weight and blood concentrations of TAG, total cholesterol, HDL-cholesterol and fasting blood glucose. Liver-related gene expressions in hyperglycaemic (HFD-fed and STZ-treated) compared with control mice showed eighty-four differentially expressed genes (forty-nine up-regulated and thirty-five down-regulated). In contrast, hyperglycaemic mice treated with inulin had twenty-two differentially expressed genes compared with control ones. Using Illumina high-throughput sequencing technology, the rarefaction and the rank abundance curves as well as the α diversity indices showed the treatment-induced differences in bacterial diversity in intestine. The linear discriminant analysis of effect size showed that the inulin treatment improved intestinal microbiota; in particular, it significantly increased the number of Bacteroides in the intestine of mice. In conclusion, inulin is potentially an effective functional food for the prevention and/or treatment of hyperglycaemia.

Evaluation of the effects of different stocking densities on growth and stress responses of juvenile hybrid grouper ♀ Epinephelus fuscoguttatus × â™‚ Epinephelus lanceolatus in recirculating aquaculture systems.

This study was aimed at evaluating the physiological and metabolic responses of juvenile hybrid grouper ♀ Epinephelus fuscoguttatus × â™‚ Epinephelus lanceolatus to stocking density. Hybrid grouper juveniles (mean ± SE = 25.43 ± 2.36 g live mass) were stocked for 22 weeks in a recirculating aquaculture system (RAS) under four different densities: low stocking density (LD; 1.03 kg m-3 ), medium stocking density (MD; 2.06 kg m-3 ), high stocking density (HD; 3.09 kg m-3 ) and extra-high stocking density (EHD; 4.11 kg m-3 ). Biometric variables were recorded and plasma, liver, intestine and stomach samples were taken for biochemical analysis at the end of the experimental period. Final stocking densities were 6.27, 16.04, 23.77 and 28.32 kg m-3 , respectively, with significant differences in growth performance. Our results showed that the best growth rates and feed utilisation occurred in the MD group. Higher plasma cortisol and glucose levels and lower triglyceride levels reflected the stress responses in the EHD group. Moreover, the activity of aspartate and alanine transaminases was elevated in the HD and EHD groups due to enhanced gluconeogenesis. The activity of the digestive enzyme pepsin significantly increased in the MD group. We found that 2.06-3.09 kg m-3 is the most suitable starting density for culturing juvenile hybrid grouper in recirculating aquaculture systems.

Vegetation succession influences soil carbon sequestration in coastal alkali-saline soils in southeast China.

The area of saline soils accounts for 8% of the earth's surface, making these soils an important terrestrial carbon sink. Soil organic carbon (SOC), microbial biomass carbon (MBC), dissolved organic carbon (DOC), soil enzyme activity, and soil bacterial abundance and biodiversity were measured in four successive coastal tidal flat ecosystems representing: bare saline soil (BS), Suaeda glauca land (SL), Imperata cylindrica grassland (IG), and Jerusalem artichoke field (JF). A decrease in soil salt content resulted in increased SOC content. With vegetation succession, MBC and DOC concentrations showed a positive trend, and activities of soil urease, catalase, invertase and alkaline phosphatase increased. A next-generation, Illumina-based sequencing approach showed that Proteobacteria, Acidobacteria, Chloroflexi, Bacteroidetes, Gemmatimonadetes, Actinobacteria, Nitrospirae and Planctomycetes were the dominant bacterial communities (a total of 597 taxa were detected, and 27 genera showed significant differences among the vegetation communities). Bacterial diversity at two soil depths was enhanced with the succession of vegetation ecosystems, with the increases in operational taxonomic units (OTUs) and the Shannon and Chao1 indices ranked in the order: JF > IG > SL > BS. The SOC and C/N were the most determinant factors influencing diversity of bacterial communities in the succession ecosystems.

Integrated transcriptome, proteome and physiology analysis of Epinephelus coioides after exposure to copper nanoparticles or copper sulfate.

Copper nanoparticles (Cu-NPs) are components in numerous commercial products, but little is known about the mechanisms of their toxicity to marine fish. Here, we investigated physiology, transcriptome and proteome in Epinephelus coioides after exposure to Cu as Cu-NPs or copper sulfate (CuSO4). Aggregation, oxidation and dissolution of Cu-NPs occurred after suspension in seawater within 24 h. Cu-NPs had similar types of the histology and hematological effects as CuSO4 on E. coioides, but toxicity of Cu-NPs seems more severe than that of CuSO4. Venn diagram analyses revealed 1428 and 2239 genes with significantly altered regulation in, respectively, CuSO4 and Cu-NPs treatments; of these, 911 genes were common to both treatments. A total of 354 and 140 proteins with significantly altered regulation were identified in, respectively, CuSO4 and Cu-NPs treatments; of these, 75 proteins were common to both treatments. A total of 11,417 transcripts and 3210 proteins were assigned to gene ontology terms, clusters of orthologous groups and Kyoto encyclopedia of genes and genomes. Correlation analysis of gene and protein expressions revealed that 21 differentially expressed proteins had their regulation changed in the same direction in both Cu-NPs and CuSO4 treatments. Those genes and proteins could be used as targets for subsequent analysis, regardless of the Cu form. Among those proteins, one of the most notable changes was in proteins related to lipid transport and metabolism. This study provides an enhanced understanding of E. coioides responses to Cu-NPs or CuSO4.

The endogenous plant hormones and ratios regulate sugar and dry matter accumulation in Jerusalem artichoke in salt-soil.

The changes in content of endogenous hormones in stolons and tubers of Jerusalem artichoke (Helianthus tuberosus L.) regulate tuber growth, but the specific knowledge about the importance of balance among the endogenous hormones is lacking. Two varieties of Jerusalem artichoke (NY-1 and QY-2) were tested for the endogenous zeatin (ZT), auxins (IAA), gibberellins (GA3) and abscisic acid (ABA) in regulating sugar and dry matter accumulation in tubers. The dry matter content and sugar accumulation in tubers were correlated positively with endogenous ZT and negatively with GA3 content and GA3/ABA and IAA/ABA content ratios. Throughout the tuber formation, ZT content was higher in NY-1 than QY-2 tubers, whereas ABA content was higher in QY-2 than NY-1 tubers. The content ratios GA3/ABA and IAA/ABA were greater in NY-1 than QY-2 before tuber initiation, but QY-2 surpassed NY-1 during the tuber growth stage. The GA3/ABA and IAA/ABA content ratios declined during tuber growth. The results suggested that a dynamic balance of endogenous hormones played an important role in tuber development.

Developing and sustainably utilize the coastal mudflat areas in China.

Coastal mudflat areas are regarded as the important reserve land resource in China. Rational exploitation and development of the mudflat areas can relieve the stress of inadequate land resources. Probing into the developing models of resource exploitation of coastal tidal mudflats is one of the important components of achieving the sustainable development in the coastal areas. Therefore, the development history of coastal mudflats after 1950s in China is briefly introduced in this paper. Then, the status in quo of the modes of development and utilization of coastal mudflat in China the paper is reviewed with a special attention payed to the agricultural use of coastal resource, especially halophytes and improved salt-tolerant varieties planting, agricultural dyke pond and coastal saline-alkali soil remediation. Based on related research frontier, sustainable developmental prospects of these coastal areas are presented as well.

Balance between salt stress and endogenous hormones influence dry matter accumulation in Jerusalem artichoke.

Salinity is one of the most serious environmental stresses limiting agricultural production. Production of Jerusalem artichoke on saline land is strategically important for using saline land resources. The interaction between plant hormones and salinity stress in governing Jerusalem artichoke (Helianthus tuberosus) growth is unclear. Jerusalem artichoke (variety Nanyu-1) was grown under variable salinity stress in the field, and a role of endogenous hormones [zeatin (ZT), auxins (IAA), gibberellins (GA3) and abscisic acid (ABA)] in regulating sugar and dry matter accumulation in tubers was characterized. Under mild salt stress (≤2.2gNaClkg(-1) soil), Nanyu-1 grew well with no significant alteration of dry matter distribution to stems and tubers. In contrast, under moderate salt stress (2.7gNaClkg(-1) soil), the distribution to stem decreased and to tubers decreased significantly. Mild salt stress induced sugar accumulation in tubers at the beginning of the tuber-expansion period, but significantly inhibited (i) transfer of non-reducing sugars to tubers, and (ii) polymerization and accumulation of fructan during the tuber-expansion stage. Under different salinity stress, before the stolon growth, the ratio of IAA/ABA in leaves increased significantly and that of GA3/ABA increased slightly; during tuber development, these ratios continued to decrease and reached the minimum late in the tuber-expansion period. While, salt stress inhibited (i) underground dry matter accumulation, (ii) tuber dry matter accumulation efficiency, (iii) transport of non-reducing sugars to tubers, and (iv) fructan accumulation efficiency during the tuber-expansion period; these effects were accompanied by significantly decreased tuber yield with an increase in salinity. With soil salinity increasing, the synthesis of IAA and GA3 was inhibited in leaves and tubers, while ABA synthesis was stimulated. In brief, tuber yield would significantly decreased with the increase of salinity.

Salinity altered root distribution and increased diversity of bacterial communities in the rhizosphere soil of Jerusalem artichoke.

The interaction between roots and bacterial communities in halophytic species is poorly understood. Here, we used Jerusalem artichoke cultivar Nanyu 1 (NY-1) to characterise root distribution patterns and determine diversity and abundance of bacteria in the rhizosphere soil under variable salinity. Root growth was not inhibited within the salinity range 1.2 to 1.9 g salt/kg, but roots were mainly confined to 0-20 cm soil layer vertically and 0-30 cm horizontally from the plant centre. Root concentrations of K(+), Na(+), Mg(2+) and particularly Ca(2+) were relatively high under salinity stress. High salinity stress decreased soil invertase and catalase activity. Using a next-generation, Illumina-based sequencing approach, we determined higher diversity of bacteria in the rhizosphere soil at high than low salinity. More than 15,500 valid reads were obtained, and Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria predominated in all samples, accounting for >80% of the reads. On a genus level, 636 genera were common to the low and high salinity treatments at 0-5 cm and 5-10 cm depth. The abundance of Steroidobacter and Sphingomonas was significantly decreased by increasing salinity. Higher Shannon and Chao 1 indices with increasing severity of salt stress indicated that high salt stress increased diversity in the bacterial communities.

Copper Nanoparticles and Copper Sulphate Induced Cytotoxicity in Hepatocyte Primary Cultures of Epinephelus coioides.

Copper nanoparticles (Cu-NPs) were widely used in various industrial and commercial applications. The aim of this study was to analyze the cytotoxicity of Cu-NPs on primary hepatocytes of E.coioides compared with copper sulphate (CuSO4). Cultured cells were exposed to 0 or 2.4 mg Cu L-1 as CuSO4or Cu-NPs for 24-h. Results showed either form of Cu caused a dramatic loss in cell viability, more so in the CuSO4 than Cu-NPs treatment. Compared to control, either CuSO4 or Cu-NPs significantly increased reactive oxygen species(ROS) and malondialdehyde(MDA) concentration in hepatocytes by overwhelming total superoxide dismutase (T-SOD) activity, catalase(CAT) activity and glutathione(GSH) concentration. In addition, the antioxidative-related genes [SOD (Cu/Zn), SOD (Mn), CAT, GPx4] were also down-regulated. The apoptosis and necrosis percentage was significantly higher after the CuSO4 or Cu-NPs treatment than the control. The apoptosis was induced by the increased cytochrome c concentration in the cytosol and elevated caspase-3, caspase-8 and caspase-9 activities. Additionally, the apoptosis-related genes (p53, p38ß and TNF-α) and protein (p53 protein) were up-regulated after the CuSO4 or Cu-NPs treatment, with CuSO4 exposure having a greater effect than Cu-NPs. In conclusion, Cu-NPs had similar types of toxic effects as CuSO4 on primary hepatocytes of E.coioides, but toxicity of CuSO4 was more severe than that of Cu-NPs.

Pepino (Solanum muricatum) planting increased diversity and abundance of bacterial communities in karst area.

Soil nutrients and microbial communities are the two key factors in revegetation of barren environments. Ecological stoichiometry plays an important role in ecosystem function and limitation, but the relationships between above- and belowground stoichiometry and the bacterial communities in a typical karst region are poorly understood. We used pepino (Solanum muricatum) to examine the stoichiometric traits between soil and foliage, and determine diversity and abundance of bacteria in the karst soil. The soil had a relatively high pH, low fertility, and coarse texture. Foliar N:P ratio and the correlations with soil nitrogen and phosphorus suggested nitrogen limitation. The planting of pepino increased soil urease activity and decreased catalase activity. Higher diversity of bacteria was determined in the pepino rhizosphere than bulk soil using a next-generation, Illumina-based sequencing approach. Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes were the dominant phyla in all samples, accounting for more than 80% of the reads. On a genus level, all 625 detected genera were found in all rhizosphere and bulk soils, and 63 genera showed significant differences among samples. Higher Shannon and Chao 1 indices in the rhizosphere than bulk soil indicated that planting of pepino increased diversity and abundance of bacterial communities in karst area.

A Comparison Effect of Copper Nanoparticles versus Copper Sulphate on Juvenile Epinephelus coioides: Growth Parameters, Digestive Enzymes, Body Composition, and Histology as Biomarkers.

Copper nanoparticles (Cu-NPs) are components in numerous commercial products, but little is known about their potential hazard in the marine environments. In this study the effects of Cu-NPs and soluble Cu on juvenile Epinephelus coioides were investigated. The fish were exposed in triplicate to control, 20 or 100 µg Cu L(-1) as either copper sulphate (CuSO4) or Cu-NPs for 25 days. The growth performance decreased with increasing CuSO4 or Cu-NPs dose, more so in the CuSO4 than Cu-NPs treatment. Both forms of Cu exposure inhibited activities of digestive enzymes (protease, amylase, and lipase) found in liver, stomach, and intestine. With an increase in CuSO4 and Cu-NPs dose, crude protein and crude lipid decreased, but ash and moisture increased, more so in the CuSO4 than Cu-NPs treatment. The Cu-NPs treatment caused pathologies in liver and gills, and the kinds of pathologies were broadly of the same type as with CuSO4. With an increase in CuSO4 or Cu-NPs dose, the total polyunsaturated fatty acids decreased, but total monounsaturated fatty acids and total saturated fatty acids increased compared to control. Overall, these data showed that Cu-NPs had a similar type of toxic effects as CuSO4, but soluble Cu was more toxic than Cu-NPs.

Effect of copper nanoparticles and copper sulphate on oxidation stress, cell apoptosis and immune responses in the intestines of juvenile Epinephelus coioides.

Copper nanoparticles (Cu-NPs) are widely used in various industrial and commercial applications, but little is known about their potential hazard in the intestines of marine teleosts. In this study we investigated the effects of Cu-NPs and soluble Cu in the intestines of juvenile Epinephelus coioides. The fish were exposed in triplicate to control, 20 or 100 µg Cu L(-1) as either copper sulphate (CuSO4) or Cu-NPs for 25 days. With an increase in Cu-NPs or CuSO4 dose, the concentration of malonaldehyde in the intestines significantly increased, whereas the activities of total superoxide dismutase and catalase as well as glutathione concentration decreased compared to the control. Statistical analysis of an apoptosis index of intestinal cells showed that general dose-dependent apoptosis was induced by Cu-NPs or CuSO4, with Cu-NPs inducing the significantly higher apoptosis index than CuSOv. Caspase-3 and caspase-9 activities were increased with an increase in Cu-NPs or CuSO4 dose, more so in the Cu-NPs than CuSO4 treatment. With an increase in Cu-NPs or CuSOv dose, succinate dehydrogenase and Na(+)-K(+)-ATPase activity and cytochrome c concentration in mitochondria decreased, accompanied by increased cytochrome c concentration in the cytosol. Concentration of heat shock proteins 70 and 90 in the intestines and expression of corresponding genes were enhanced with an increase in the Cu-NPs or CuSOv dose, but the concentrations and expressions of immunoglobulin M and lysozyme decreased (more in the Cu-NPs than CuSO4 treatment) compared to the control. Expression of interleukin-1beta and tumor necrosis factor-alpha showed a dose-dependent increase with the increased Cu-NPs or CuSO4 dose, with the highest expression found in the Cu-NPs treatment. In conclusion, Cu-NPs had similar toxic effects as CuSOv in the intestines of juvenile E. coioides, but toxicity of Cu-NPs was more severe than that of CuSO4.

Analysis of phenolic acids of Jerusalem artichoke (Helianthus tuberosus L.) responding to salt-stress by liquid chromatography/tandem mass spectrometry.

Plant phenolics can have applications in pharmaceutical and other industries. To identify and quantify the phenolic compounds in Helianthus tuberosus leaves, qualitative analysis was performed by a reversed phase high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) and quantitative analysis by HPLC. Ten chlorogenic acids (CGAs) were identified (3-o-caffeoylquinic acid, two isomers of caffeoylquinic acid, caffeic acid, p-coumaroyl-quinic acid, feruloylquinic acid, 3,4-dicaffeoyquinic acid, 3,5-dicaffeoylquinic acid, 1,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid) by comparing their retention times, UV-Vis absorption spectra, and MS/MS spectra with standards. In addition, four other phenolic compounds, including caffeoyl glucopyranose, isorhamnetin glucoside, kaempferol glucuronide, and kaempferol-3-o-glucoside, were tentatively identified in Helianthus tuberosus leaves for the first time. The 3-o-caffeoylquinic acid (7.752 mg/g DW), 4,5-dicaffeoylquinic acid (5.633 mg/g DW), and 3,5-dicaffeoylquinic acid (4.900 mg/g DW) were the major phenolic compounds in leaves of Helianthus tuberosus cultivar NanYu in maturity. The variations in phenolic concentrations and proportions in Helianthus tuberosus leaves were influenced by genotype and plant growth stage. Cultivar NanYu had the highest concentration of phenolic compounds, in particular 3-o-caffeoylquinic acid and 4,5-dicaffeoylquinic acid compared with the other genotypes (wild accession and QingYu). Considering various growth stages, the concentration of total phenolics in cultivar NanYu was higher at flowering stage (5.270 mg/g DW) than at budding and tuber swelling stages. Cultivar NanYu of Helianthus tuberosus is a potential source of natural phenolics that may play an important role in the development of pharmaceuticals.

Gene cloning, sequence analysis, and expression profiles of a novel ß-ring carotenoid hydroxylase gene from the photoheterotrophic green alga Chlorella kessleri.

In this study, a full-length complementary DNA (cDNA) sequence of ß-ring carotenoid hydroxylase (CHY), designated Ckecyp97a1, was isolated via reverse transcription-polymerase chain reaction and rapid amplification of cDNA ends (RACE) methods. The cloned Ckecyp97a1 cDNA was 2,264-bp in length, and contained an open reading frame (ORF) of 1,944-bp with 5'-terminal untranslated region (UTR) of 66-bp and 3'-terminal UTR of 254-bp and encoded a ß-ring CHY protein of 647 amino acids. The deduced protein had a calculated molecular mass of 71.43 kDa with an estimated isoelectric point (pI) of 6.72. Multiple sequence alignment and phylogenetic analysis revealed that Ckecyp97a1 was homologs to known chloroplastic cytochrome P450 (P450) CHY. The typical catalytic motifs of the P450 were highly conserved in the protein sequences of CkeCYP97A1. The Ckecyp97a1 transcriptional expression and carotenoids accumulation were observed under high light (HL) of different wavelengths (white: 390-770 nm and blue: 420-500 nm). The results revealed that Ckecyp97a1 transcript increased strongly throughout the course of the HL illumination treatment (22-70 h) under white HL treatment, while decreased during 10-58 h under blue HL treatment. The concentrations of lutein, α-carotene, and ß-carotene were relatively steady and below the control level under both treatments. The zeaxanthin concentration was higher under white HL treatment than those under control and blue HL treatments. Ckecyp97a1 gene showed different expression patterns under different light wavelengths treatments. The data obtained in this study demonstrates that CkeCYP97A1 is the enzyme responsible for carotenoid hydroxylation involved in HL acclimation for photoheterotrophic green alga Chlorella kessleri CGMCC 4917.

Colonization by endophytic Ochrobactrum anthropi†Mn1 promotes growth of Jerusalem artichoke.

The Ochrobactrum anthropi Mn1 strain, taxonomically identified using 16S ribosomal DNA sequence, was isolated from roots of Jerusalem artichoke. Its endophytic colonization was investigated microscopically using green fluorescent protein introduced by vector pHC60. The strain entered Jerusalem artichoke tissues through the root, and was localized in the roots and stems. The plant growth-promoting (PGP) effects of O. anthropi Mn1 were assessed in greenhouse as well as field trials with different nitrogen supplies. Only under moderate to ample nitrogen supply, could O. anthropi Mn1 promoted growth of host plant. The PGP effects of the strain were symbiotic nitrogen fixation, root morphological optimization and enhanced nutrient uptake. We hypothesize that the symbiotic interspecies interaction might be quorum sensing related.

Tissue fractions of cadmium in two hyperaccumulating Jerusalem artichoke genotypes.

In order to investigate the mechanisms in two Jerusalem artichoke (Helianthus tuberosus L.) genotypes that hyperaccumulate Cd, a sand-culture experiment was carried out to characterize fractionation of Cd in tissue of Cd-hyperaccumulating genotypes NY2 and NY5. The sequential extractants were: 80% v/v ethanol (FE), deionized water (FW), 1 M NaCl (FNaCl), 2% v/v acetic acid (FAcet), and 0.6 M HCl (FHCl). After 20 days of treatments, NY5 had greater plant biomass and greater Cd accumulation in tissues than NY2. In both genotypes the FNaCl fraction was the highest in roots and stems, whereas the FAcet and FHCl fractions were the highest in leaves. With an increase in Cd concentration in the culture solution, the content of every Cd fraction also increased. The FW and FNaCl ratios in roots were lower in NY5 than in NY2, while the amount of other Cd forms was higher. It implied that, in high accumulator, namely, NY5, the complex of insoluble phosphate tends to be shaped more easily which was much better for Cd accumulation. Besides, translocation from plasma to vacuole after combination with protein may be one of the main mechanisms in Cd-accumulator Jerusalem artichoke genotypes.

Functional analyses of a putative plasma membrane Na+/H+ antiporter gene isolated from salt tolerant Helianthus tuberosus.

Jerusalem artichokes (Helianthus tuberosus L.) can tolerate relatively higher salinity, drought and heat stress. In this paper, we report the cloning of a Salt Overly Sensitive 1 (SOS1) gene encoding a plasma membrane Na(+)/H(+) antiporter from a highly salt-tolerant genotype of H. tuberosus, NY1, named HtSOS1 and characterization of its function in yeast and rice. The amino acid sequence of HtSOS1 showed 83.4% identity with the previously isolated SOS1 gene from the Chrysanthemum crassum. The mRNA level in the leaves of H. tuberosus was significantly up-regulated by presence of high concentrations of NaCl. Localization analysis using rice protoplast expression showed that the protein encoded by HtSOS1 was located in the plasma membrane. HtSOS1 partially suppressed the salt sensitive phenotypes of a salt sensitive yeast strain. In comparison with wild type (Oryza sativa L., ssp. Japonica. cv. Nipponbare), the transgenic rice expressed with HtSOS1 could exclude more Na(+) and accumulate more K(+). Expression of HtSOS1 decreased Na(+) content much larger in the shoot than in the roots, resulting in more water content in the transgenic rice than WT. These data suggested that HtSOS1 may be useful in transgenic approaches to improving the salinity tolerance of glycophyte.

Cloning and expression of a cytosolic HSP90 gene in Chlorella vulgaris.

Heat shock protein 90 (HSP90), a highly conserved molecular chaperone, plays essential roles in folding, keeping structural integrity, and regulating the subset of cytosolic proteins. We cloned the cDNA of Chlorella vulgaris HSP90 (named CvHSP90) by combining homology cloning with rapid amplification of cDNA ends (RACE). Sequence analysis indicated that CvHSP90 is a cytosolic member of the HSP90 family. Quantitative RT-PCR was applied to determine the expression level of messenger RNA (mRNA) in CvHSP90 under different stress conditions. C. vulgaris was kept in different temperatures (5-45 °C) for 1 h. The mRNA expression level of CvHSP90 increased with temperature from 5 to 10 °C, went further from 35 to 40 °C, and reached the maximum at 40 °C. On the other hand, for C. vulgaris kept at 35 °C for different durations, the mRNA expression level of CvHSP90 increased gradually and reached the peak at 7 h and then declined progressively. In addition, the expression level of CvHSP90 at 40 or 45 in salinity (‰) was almost fourfold of that at 25 in salinity (‰) for 2 h. Therefore, CvHSP90 may be a potential biomarker to monitor environment changes.

The potential toxicity of copper nanoparticles and copper sulphate on juvenile Epinephelus coioides.

Copper nanoparticles (Cu-NPs) were widely used in various industrial and commercial applications. In this study the effects of Cu-NPs and soluble Cu were investigated on juvenile Epinephelus coioides. The fish were exposed in triplicate to control, 20 or 100µgCuL(-1) as either copper sulphate (CuSO4) or Cu-NPs in a semi-static aqueous culture for 25 days. The growth parameters were significantly lower at 100µgCuL(-1) as CuSO4 or Cu-NPs treatment compared to control. Time-dependent Cu accumulation in all tissues increased with increasing the Cu dose. The percentage of total Cu found in remaining tissues (head, bones, fins, etc.) decreased more in the CuSO4 than Cu-NPs treatment after 25 days, but increased in all other tissues (especially in liver). Compared with the control, either Cu-NPs or CuSO4 induced higher malonaldehyde concentration in tissues by overwhelming total superoxide dismutase activity, total glutathione concentration and Na(+)/K(+)-ATPase activity, but the opposite results were recorded for the brain. With increasing the CuSO4 or Cu-NPs dose, apoptosis was exacerbated in the liver and gills, more so by CuSO4 than Cu-NPs. Overall, these findings showed that Cu-NPs had the toxic effects similar to dissolved Cu; hence, Cu-NPs need to be included in the assessment of toxicological impacts in the aquatic environment.