Generation and analysis of expressed sequence tags from the salt-tolerant eelgrass species, Zostera marina

Zostera marina, a monocotyledonous angiosperm, is one of the most important seagrass species. To inves- tigate the salt-tolerance mechanism and discover salt-tolerant genes in Z. marina, a cDNA library was con- structed. Single-pass sequencing of the 5＇ ends of 4 081 clones yielded 4 002 high quality expressed sequence tags （ESTs）, which were assembled into 241 contigs and 1 673 singletons, representing 1 914 unigenes. The average length of the ESTs was 582 bp, with sizes ranging from 100-1 500 bp. Basic Local Alignment Search Tool （BLASTX） analysis revealed that 1 664 unigenes had significant homology to known genes in the Na- tional Center for Biotechnology Information （NCBI） non-redundant （nr） database （E-value≤5-10）. Among them, the two most abundant genes encoded metallothionein （157 ESTs） and chlorophyll a/b-binding pro- tein （38 ESTs）, accounting for 7.1% and 1.7% of the total ESTs, respectively. Using Kyoto Encyclopedia of Genes and Genomes （KEGG）, 1 462 unigenes were assigned to 1 161 pathways （E-value≤5-10）. A total of 938 unigenes were assigned Gene Ontology （GO） terms based on the GO hierarchy analysis, and InterProScan searches recognized 1 003 InterPro families. Three genes for metallothionein in Z. marina that belonged to Class II was identified. Results of this study will improve understanding of the molecular mechanisms of saline tolerance in Z. marina.

Decolorization of azo dyes with high salt concentration by salt-tolerant mixed cultures under anaerobic conditions

Because the lack of detailed study of biological decolorization in high salt dye wastewater, it is still difficult to evaluate the biological treatment on high-salinity dye wastewater. The experiments were carried out to study the salt-tolerant bacteria, which is useful in the treatment of high-salinity colored wastewater. Simulated wastewater containing 5-150 g/L salt （NaCI） and 50-2000 mg/L Reactive Brilliant Red K-2BP was treated with three salt-tolerant mixed cultures （CAS, TAS, DSAS）, which were under a gradually acclimated procedure. With the increase of concentrations of salt and dye, the decolorization became low. The abilities of decolorization of dyes wastewater by three mixed cultures （CAS, TAS, DSAS） were studied, CAS and DSAS mixed cultures showed more active for the treatment of high-salinity colored wastewater than TAS mixed cultures. The results suggested that there might be a simple process for the high salt wastewater treatment, which could be incorporated into conventional activated sludge plants.

Rheological properties of salt-tolerant HPAM solutions with ultrahigh molecular weight

The rheological properties of salt-tolerant partially hydrolyzed polyacrylamide(HPAM)solutions with molecular of 2.5×107 g/mol at different concentrations were measured in steady-state shear flow mode by Haake Rheostress 150 rheometer.Three constitutive equations(Oldroyd four constant model,Guesekus model and FENE-P model) were used for describing the apparent viscosity and first normal stress difference.The apparent viscosity of salt-tolerant HPAM solutions appears a first Newtonian zone when the shear rate is approximately lower than 0.2 s-1.At high shear rate,the HPAM solutions show shear-thinning and elasticity.The results show that the FENE-P model has the best agreement between theoretical and experimental data within the available shear rate range.The material parameters are useful for numerical analysis of polymer solution flow fields.

Response of Salt-Tolerant Rice Varieties to Biocompost Application in Sodic Soil of Eastern Uttar Pradesh

Sodic soils have immense productivity potential, if managed through proper technology interventions. Biocompost is prepared by composting pressmud (a sugar industry byproduct) received from cane juice filtration and spent wash received from distilleries through microbial aerobic decomposition and can be used to reclaim sodic soils. Field experiments were conducted during the wet season of 2011 and 2012 to study the effect of incorporation of biocompost in sodic soil with four treatments: T1—Control, T2—Biocompost at 2 t ha-1, T3—Biocompost at 4 t ha-1 and T4—Biocompost at 6 t ha-1. The two promising salt tolerant rice varieties preferred by farmers, Narendra usar 3 and NDR 359 were used as test crops, which can produce yields ranging between 2-4 t ha-1 in soil having a pH range of 9.2 to 10.5. Among the different doses of biocompost tested, application of biocompost at 6 t ha-1 registered highest yields, enabled by a higher biomass, ear bearing tiller (EBT), and grain fertility in both varieties. Narendra usar 3 was more responsive to treatments even at lower doses of biocompost than NDR 359, but NDR 359 yielded slightly higher than Narendra usar 3 in all treatments. Soil health was also improved evidently on better fertility and low soil pH and EC at harvest. Thus, biocompost can be considered as a commercially viable, environmentally acceptable and practically enforceable option for improving the crop productivity and soil fertility status.

Chemical Composition and Ruminal Digestibility of Ceratoides, a Salt-tolerant Perennial Plant,at Different Years

It has been proposed that salt-tolerant plant could be used as a feed resource for ruminants whereby salt would be removed from salinized land (Asian -Aust. J. Anim. Sci. (2002) 15:998 -1001). Ceratoides arborescens (Losinsk.) Tsien et C. G. Ma is known as a drought-and salt-tolerant plant,a kind of shrubs, growing in semi-arid land of Inner Mongolia. Because the covering effect of the perennial plant as a mulch over the soil might be expected, the optimum covering effect would be obtained after the growth period.The perennial plant produces seeds around summer and end its growth thereafter. Nutrient value of the perennial salt-tolerant plant, however,had not been reported in flowering period at different year. It is necessary to know the ruminal degradability of the plants of each growing year in order to determine the regimen to diet for ruminants. The present experiment,therefore,was undertaken to analyze the digestibility and chemical composition of Ceratoides arborescens as feed for ruminants.

Salt-tolerant mechanism of marine Aspergillus niger cellulase cocktail and improvement of its activity

The cellulase cocktail produced by marine Aspergillus niger exhibits a property of salt-tolerance,which is of great potential in cellulose degradation in high salt environment.In order to explain the mechanism on the salttolerance of the cellulase cocktail produced by marine A.niger,six cellulase components(AnCel6,AnCel7A,AnCel7B,AnEGL,AnBGL1 and AnBGL2)were obtained by directed expression.Studies on their enzymatic properties revealed that oneβ-glucosidase(AnBGL2)and one endoglucanase(AnEGL)exhibited an outstanding salttolerant property,and one cellobiohydrolase(AnCel7B)exhibited a certain salt-tolerant property.Subsequent study revealed that the salt-tolerant An EGL and AnCel7B endowed the cellulase cocktail with stronger salttolerant property,while the salt-tolerant An BGL2 had no positive effect.Moreover,after overexpression of AnCel6,AnCel7A,AnCel7B and AnEGL,the activity of cellulase cocktail increased by 80%,70%,63%and 68%,respectively.However,the activity of cellulase cocktail was not improved after overexpression of AnBGL1 and AnBGL2.After mixed-strain fermentation with cellobiohydrolase recombinants(cel6 a,cel7a and cel7b recombinants)and endoglucanase recombinant(egl recombinant),the the activity of cellulase cocktail increased by 114%,102%and91%,respectively.

Differential gene expression in salt-tolerant rice mutant and its parental variety

The differential expressions of three genes rbcL, salT and rab!6 in response to ABA, NaCl, PEG and heat shock were investigated in seedlings of a salt-tolerant rice mutant 20 (mutant 20) and its parental variety Oryza sativa var. japonica 77-170(170). By Northern blot analysis it was found that ABA induced the expression of all three genes of rbcL, salT and rab16 in shoots and roots of both 170 and mutant 20 with the exceptions of rab16 in shoots of mutant 20 and rbcL in roots of 170. Lower concentrations of NaCl induced rbcL expression in shoots of mutant 20 but not 170. Higher concentrations of NaCl decreased rbcL expression but induced expressions of salT and rab16 in shoots of both 170 and mutant 20. PEG(15%) and 37℃ heat shock showed almost no effects on the expression of the three genes in mutant 20. However, they caused a decrease in rbcL expression and slight induction of the rab16 gene in 170, with salT expression unaffected. These results indicated that mutant 20 was relatively less

Analysis of genes specifically expressed under salt stress in salt-tolerant mutant of rice by using DDRT-PCR technique

Differential display reverse transcription-PCR (DDRT-PCR) technique was used to identify those genes that are expressed differentially between wild type rice variety 77-170 (Oryza Sativa vas Japonica) and its salt-tolerant mutant (M-20) under salt stress. Totally 13 salt-inducible cDNA fragments of 200-600 bp were identified and doned, and were designated as SIGR1 - SIGR13 (salt-induced gene in rice). Northern blot analysis showed that expression of SIGR6 and SIGR8 was salt-inducible in both wild type and mutant, and expression of SIGR12 in M-20 was much higher than that in 77-170 under salt stress. It was also shown that expression of SIGR3, SIGR4, SIGR7, SIGRIO and SIGR13 was salt-inducible, and the genes were highly homologous with Rab1d which was an ABA-inducible gene of rice. The great potential application of DDRT-PCR technique in plant molecular biology research may promote the investigation of expression of salt-induced protein in rice.

Enhanced H^+ transport activity of tonoplast vesicles isolated from roots of salt-tolerant mutant of wheat under NaCl stress

Both enhanced were H^+ transport activities of tonoplast vesicles isolated from roots of the salt-tolerant mutant and wild type of wheat with treatment of NaCI, but the activity of the mutant was significantly higher than that of wild type. H^+ transport activity was indicated as the stable value of fluorescence quenching per mg membrane proteins. The H^+ transport activities dependent on ATP of the mutant and wild type were 1099 and 558 respectively and their activities dependent on PPi were 358 and 228 separately.

Reduced Na^+ and K^+ permeability of K^+ channel in plasma membrane isolated from roots of salt-tolerant mutant of wheat

The Na^+ and K^+ permeability of K^+ channel in plasma membrane, isolated from roots of the salt-tolerant mutant of ,wheat, was lower than that of wild type in 100 mmol/L KCI and NaCI solution. The opening frequency of K^+ channel of the mutant reduced more significantly than that of wild type in two kinds of solution mentioned above. It is assumed that the reduction of opening frequency mainly contributes to the Na^+ and K^+ permeability of K^+ channel of the mutant. The electric conductance of single-channel of the mutant was similar to that of wild type and the main difference between them was exhibited as the opening frequency. Their K^+/Ka^+ selectivity of K^+ channel had no significant difference. The K^+/Na^+ selectivity of the mutant and wild type was 3.35 and 3. 18 respectively.

Putrescine Plays a Positive Role in Salt-Tolerance Mechanisms by Reducing Oxidative Damage in Roots of Vegetable Soybean

Polyamines play important roles in plant tolerance to environmental stress. With the aim of investigating the possible involvement of putrescine （Put） in salt-tolerance mechanisms in vegetable soybean roots, exogenous Put （10 mmol L＂） and its biosynthetic inhibitor D-arginine （D-Arg） （0.5 mmol L-1） were added to nutrient solution when vegetable soybean （Glycine max L. cv. Huning 95-1） seedlings were exposed to 100 mmol L^-11 sodium chloride （NaCl）. The results showed that Put ameliorated but D-Arg aggravated the detrimental effects of NaCl on plant growth and biomass production. Under NaCl stress, levels of free, soluble conjugated and insoluble bound types of Put in roots of vegetable soybean were reduced, whereas those of free, soluble conjugated, and insoluble bound types of spermidine （Spd） and spermine （Spm） were increased. Exogenous Put eliminated the decrease in Put but promoted the increase of Spd and Spm. However, these changes could be reversed by D-Arg. Under NaCl stress, activities of arginine decarboxylase （ADC）, S-adenosylmethionine decarboxylase （SAMDC）, diamine oxidase （DAO）, and polyamine oxidase （PAO） were induced, with exogenous Put promoting and D-Arg reversing these changes. Furthermore, NaCl stress decreased activities of antioxidant enzymes. Exogenous Put alleviated but D-Arg exaggerated these effects of NaCl stress, resulting in the same changes in membrane damage and reactive oxygen species （ROS） production. These results indicated that Put plays a positive role in vegetable soybean roots by activating antioxidant enzymes and thereby attenuating oxidative damage.

Rheological Properties of Hydrophobically Associating Polyacrylamide Solution

A temperature-resistant, salt-tolerant polyacrylamide, hydrophobically associating polymer （HAP）, was synthesized in the State Key Laboratory of Heavy Oil Processing. The rheological behavior of HAP solution was investigated by means of flow experiments in porous media and by using a HAAKE RS600 rheometer. The results of Nuclepore membrane filtration showed that filtration time increased sharply when the critical association concentration was reached. Shear rate had a greater impact on viscosity and shear stress with increasing HAP concentration. The HAP solution with a concentration of 100 mg/L （salinity 32,868 mg/L） exhibited negative thixotropy. However, at the same salinity the HAP solution showed thixotropy and its viscosity became greater when the polymer concentration increased to 1,500 mg/L. The flow experiments in cemented core samples indicated that the resistance factor and residual resistance factor of the HAP solution were 31.8 and 12 when polymer concentration and salinity were 1,500 mg/L, 32,868 mg/L at 85℃ respectively, which is favorable for flooding application. Such factors of partially hydrolyzed polyaerylamide 3530S were merely 3.14 and 1.71, so it could not be applied to polymer flooding in the oilfield with high temperature and high salinity.

耐温抗盐驱油共聚物的合成

用胶束聚合方法,将丙烯酰胺(AM)与疏水单体N-正辛基丙烯酰胺(C_8AM)、极性阴离子单体2-丙烯酰胺基-2-甲基丙磺酸(AMPS)进行共聚,合成了AM-C_8AM-AMPS疏水性缔合三元共聚物作为驱油剂,命名为KYP。研究了十二烷基硫酸钠的质量分数、引发温度、单体的摩尔分数、尿素的浓度对聚合物溶液(ρ=1 mg/L)在总矿化度为6.5 g/L的模拟盐水中表观粘度的影响。结果表明:C_8AM和AMPS的摩尔分数分别为0.7％和20％、引发温度为11℃、尿素的浓度为0.2 mmol/L时,合成的KYP具有很好的增粘效果。

Potential of Novel Halotolerant and Psychrotrophic Strain of Planococcus sp. for Water Treatment

To screen multifunctional bacteria for water treatment,a chemical oxygen demand( COD)degradation and flocculation strain S2 A15 was obtained from the offshore sewage outfall at Weihai International Beach. Based on the phylogenetic characteristics,a novel strain was identified as a Planococcus species. Strain S2 A15 was determined to have the ability of flocculation and COD degradation. A series of experiments showed that the strain S2 A15 could be used for the treatment of four types of wastewater,including domestic wastewater( 400 mg/L and 800 mg/L) and high salt domestic wastewater( 400 mg/L and 800 mg/L). Among them,the best effect was exerted by the strain that reduced by 76.9% in domestic wastewater with 400 mg/L COD. The flocculation ratio reached 60.19%. The optimal treatment conditions are also discussed. We confirmed that the strain S2 A15 had salt tolerance and low temperature resistance. The best growth of S2 A15 at salt concentration of 6% and further confirmed that the strain could degrade COD at a low temperature.

QTL mapping by whole genome re-sequencing and analysis of candidate genes for salt tolerance in linseed(Linum usitatissmum L.)

Soil salinization is detrimental to the growth and development of flax and ultimately leads to a decrease in yield.However,the molecular mechanism of linseed response to salt stress is still unclear.In this study,a salt-tolerant(ST)linseed variety STS and a salt-sensitive(SS)variety DYM were selected as experiment materials.Bulk segregation analysis and whole-genome resequencing technologies were performed to map salt tolerance quantitative trait loci(QTL).A total of 38,625 QTL loci were identified.Fifteen genes(which were not annotated in the reference genome)were identified within a 2.597 Mb region in chromosome 1.Two salt tolerance candidate genes Lus.o.m.scaffold91.141 and Lus.o.m.Scaffold1.14 encoding WD40 and cytochrome P450 were identified by predicting protein functions.Previous studies showed that WD40 and cytochrome P450 could significantly improve plant salt stress tolerance.In this paper,results showed that Lus.o.m.scaffold91.141 and Lus.o.m.Scaffold1.14 might be involved in response to salt stress in lineseed.The fine mapping and functional analysis of these genes provide a molecular breeding basis for the genetic improvement of high salt-tolerant linseed varieties.

Preliminary Characterization of a Cellulase Producing Bacterial Strain Isolated from a Romanian Hypersaline Lake

Cellulases are a group of enzymes that are used in many biotechnological processes. Since most of the enzymes synthesised by mesophilic microorganisms are unstable in industrial environments, it is necessary to direct research towards extremophile cellulolytic microorganisms because the enzymes synthesised by them are stable and active even in harsh physicochemical conditions. In the present investigation, our aim was to isolate and identify some microbial cellulolytic strains from a hypersaline lake located in Romania and to determine their optimal growth conditions. Of a total of 25 microbial strains isolated, only one extreme halotolerant bacterial strain was able to produce an endoglucanase. Based on molecular identification, we identified this cellulolytic strain as a species of Bacillus genus, most closely related to Bacillus zhangzhouensis. Optimal growth conditions were found to be at 15°C, pH 7.5 and 2 M NaCl. Endoglucanase activity of this bacterial strain is influenced by both salinity and temperature. The most significant endoglucanase activity was detected in the presence of 3 M NaCl, after 72 h of incubation at 15°C. In this situation, the amount of glucose released from a volume of 0.5 mL of 2% (w/v) carboxymethyl cellulose substrate is equivalent to 2.05 mg. In conclusion, this study represents the first preliminary characterization of a B. zhangzhouensis strain that has the ability to degrade cellulose and that demonstrates tolerance to high salt concentrations.

Synthesis of temperature-resistant and salttolerant surfactant SDB-7 and its performance evaluation for Tahe Oilfield flooding (China)

In order to improve the enhanced oil recovery of high-temperature and high-salt oilfields, a novel temperature-resistant and salt-tolerant surfactant （denoted as SDB-7） was synthesized and evaluated for the Tahe Oilfield （Xinjiang, China）, which is representative of high-temperature and high-salt oilfields. It has a central reservoir temperature of 140 ℃ and salinity of 22.6× 10^4 mg/L. The temperature-resistant and salt-tolerant performance, interfacial activity, oil displacement efficiency, aging properties, and adsorption properties of the synthesized surfactant were evaluated for Tahe Oilfield flooding. The results showed that the SDB-7 was temperature-resistant and salt-tolerant capacity of 140 ℃ and 22.6×10^4 rag/ L, respectively, oil displacement efficiency under static condition of 84%, and adsorption loss of 0.4 mg/ g （less than 1 mg/g-oil sand）. In the heat aging experiment （under the temperature of 140 ℃ for 60 days）, the oil-water interracial tension and oil displacement efficiency of SDB-7 were almost unchanged. The oil displacement experiments showed that, under the temperature of 140 ℃ and the salinity of 22.6× 10^4 mg/L, the surfactant SDB-7 can enhance oil recovery by 14.5% after water flooding,suggesting that SDB-7 has a promising application in high temperature and high salinity （HT/HS） reservoir.

CLONING,SEQUENCING AND DETERMINATION OF THE GENE FRAGMENT OF α-CHAIN OF ATP SYNTHASE IN DUNALIELLA BARDAWIL

Halophilic alga Dunaliella bardawil (Chlorophyceae) was cultivated in artificialseawater (containing 3 .0, 1. 5 or 0. 5 mol/L of NaCl respectively) for at least two weeks; total RNAswere then extracted and 8 stable differential bands were harvested after DDRT-PCR and electrophoresis.The retrieved bands were amplified, subjected to electrophoresis again, and cloned into plasmid pUCm-Trespectively. After exelusion of false positive bands, We obtained a recombinant plasmid pTE containing afragment of cDNA, which was only specilically expressed under high salinity condition. Sequencing of

Gene Response to Salt Stress in Populus euphratica

Through construction of a subtracted cDNA library and library screening, a number of salt-induced cDNA fragments have been cloned from Populus euphratica. Based on the results of DNA sequencing and Northern analysis, the gene response of Populus euphratica to salt stress is discussed. It is indicated that in response to salt treatment the transcription level for some genes of Populus euphratica increases by about 1.5 times and significant difference between the responses to osmotic stress and to ion stress has been observed in gene activity.