Identifying priority protection areas of key food resources of the giant panda

Animals that live in seasonal environments adjust their reproduction cycle to optimize seasonal forage quality.Giant pandas(Ailuropoda melanoleuca)are seasonal altitudinal migrants that feed on bamboo shoots and leaves with different nutritional quality.However,the importance of bamboo shoots to giant pandas,especially small and isolated populations,is not fully appreciated.Here,we explored whether mating time of giant pandas is shaped by bamboo shoot phenology.We also assessed the intensity of ongoing bamboo shoot harvesting by local communities in 42 giant panda reserves based on questionnaire surveys.Varying intensity and protection levels of bamboo shoot harvesting were found.From these data,we developed a priority ranking scheme of protection areas for this key food resource.Our study showed that pandas time their mating behavior to coincide with bamboo shoot phenology due to the high nutritional demands associated with mating and pregnancy.We also found that bamboo shoots were not well protected in many places.Liangshan,Daxiangling,and Xiaoxiangling,containing the most isolated panda populations,were identified as the areas with the most urgent need of protection.Furthermore,equal attention should be paid to the Qiong L-B population,as this region holds considerable potential to serve as a corridor between the Minshan and Qionglai populations.To address the challenges posed by bamboo shoot harvesting,we recommend establishing more practical bamboo shoot management policies,increasing public awareness of bamboo shoot protection,and providing alternative sources of income for local communities.

Synthesis,Crystal Structure and Biological Activity of N-(2,6-Difluorobenzoyl)-N'-[5-(4-trifluoromethyl-phenyl)-1,3,4-thiadiazol-2-yl]ure

The title compound N-（2,6-difluorobenzoyl）-N＇-[5-（4-trifluoromethylphenyl）-1,3,4-thiadiazol-2-yl]urea（C17H9F5N4O2S,Mr = 428.34） has been synthesized by the reaction of 2-amino-5-（4-trifluoromethylphenyl）-1,3,4-thiadiazole with 2,6-difluorobenzoyl isocyanate,and its crystal structure was determined by single-crystal X-ray diffraction.The crystal belongs to monoclinic,space group P21/n with a = 10.7316（13）,b = 10.5617（13）,c = 16.037（2） ,β = 106.408（2）°,V = 1743.6（4） 3,Z = 4,Dc = 1.632 g/cm3,μ = 0.260 mm-1,F（000） = 864,the final R = 0.0599 and wR = 0.1420 for 3467 observed reflections with I〉 2σ（I）.The urea group,which adopts a planar configuration mediated by the intramolecular N-H...O hydrogen bond,is nearly coplanar with the thiadiazole and 4-trifluoromethylbenzene rings.The title compound was found to exhibit good fungicidal activity against Rhizoctonia solani and Botrytis cinerea.

Synthesis, Crystal Structure and Biological Properties of One Zinc(Ⅱ) Complex Based on 4-Acyl Pyrazolone Derivative

[Zn（L）（CH3OH）3]（H2L = N-（1-phenyl-3-methyl-4-propenylidene-5-pyrazolone）-salicylidene hydrazide） has been synthesized by the reaction of zinc nitrate and ligand H2 L. The complex crystallizes in orthorhombic system, space group Pbca with a = 5.888（15）, b = 14.564（14）, c = 22.20（2） , V = 5137（8） 3, Z = 8 and F（000） = 2184. The ligand serves as a negative bivalent tridentate chelating agent to coordinate with the central zinc（II） atom. DNA-binding was studied by UV-Vis spectral analysis and ethidium bromide（EB） displacement experiments. The results showed that the DNA-binding constant of the complex is 5.1×104 M–1. Antitumor activity of [Zn（L）（CH3OH）3] and the ligand have been investigated by MTT assay, which indicated that the complex has better cytotoxicity to Eca-109 and He La than free ligand.

Optimization of the Process for Preparing Bivalent Polysaccharide Conjugates to Develop Multivalent Conjugate Vaccines against Streptococcus pneumoniae or Neisseria meningitidis and Comparison with the Corresponding Licensed Vaccines in Animal Models

Objective:This study aimed to describe,optimize and evaluate a method for preparing multivalent conjugate vaccines by simultaneous conjugation of two different bacterial capsular polysaccharides(CPs)with tetanus toxoid(TT)as bivalent conjugates.Methods:Different molecular weights(MWs)of polysaccharides,activating agents and capsular polysaccharide/protein(CP/Pro)ratio that may influence conjugation and immunogenicity were investigated and optimized to prepare the bivalent conjugate bulk.Using the described method and optimized parameters,a 20-valent pneumococcal conjugate vaccine and a bivalent meningococcal vaccine were developed and their effectiveness was compared to that of corresponding licensed vaccines in rabbit or mouse models.Results:The immunogenicity test revealed that polysaccharides with lower MWs were better for Pn1-TT-Pn3 and MenA-TT-MenC,while higher MWs were superior for Pn4-TT-Pn14,Pn6A-TT-Pn6B,Pn7F-TT-Pn23F and Pn8-TT-Pn11A.For activating polysaccharides,1-cyano-4-dimethylaminopyridinium tetrafluoroborate(CDAP)was superior to cyanogen bromide(CNBr),but for Pn1,Pn3 and MenC,N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride(EDAC)was the most suitable option.For Pn6A-TT-Pn6B and Pn8-TT-Pn11A,rabbits immunized with bivalent conjugates with lower CP/Pro ratios showed significantly stronger CP-specific antibody responses,while for Pn4-TT-Pn14,higher CP/Pro ratio was better.Instead of interfering with the respective immunological activity,our bivalent conjugates usually induced higher IgG titers than their monovalent counterparts.Conclusion:The result indicated that the described conjugation technique was feasible and efficacious to prepare glycoconjugate vaccines,laying a solid foundation for developing extended-valent multivalent or combined conjugate vaccines without potentially decreased immune function.

Hepatic caecum of amphioxus and origin of vertebrate liver

Liver is characteristic of all vertebrates.As a critical hub for many physiological processes including metabolism,innate immunity,protein synthesis and detoxification,its evolutionary origin was largely underappreciated in history,and only received due attention in recent decades.It has been suggested by morphological,ultrastructural and immunohistochemical studies that the hepatic caecum of amphioxus is homologous to the liver of vertebrate species.Molecular biology studies demonstrated that amphioxus hepatic caecum expresses plenty of vertebrate liver-specific genes.Our functional studies revealed significant similarities between amphioxus hepatic caecum and vertebrate liver.We also found that the functions of hepatic caecum are subjected to the regulation of pituitary hormones just as the liver does.These provide solid evidences supporting the notion that the hepatic caecum is the homologue of liver,which may represent the first stage in chordate evolution,laying a foundation for the subsequent formation of the liver as we know it in vertebrates.Further studies on the specification and morphogenesis of hepatic caecum in amphioxus will shed more lights on the origin and evolution of vertebrate liver.

Adaptive strategy of Nitraria sibirica to transient salt,alkali and osmotic stresses via the alteration of Na+/K+fluxes around root tips

Nitraria sibirica Pall.is an important shrub with a strong salt-alkali tolerance,but the mechanism underlying this tolerance remains obscure.In this study,N.sibirica,with salt-sensitive Vigna radiata(Linn.)Wilczek as the control,was subjected to transient salt stress(100 mM NaCl),alkali stress(50 mM Na_(2)CO_(3)),and osmotic stress(175 mM mannitol).The ionic fluxes of Na^(+)and K^(+)in the root apical region were measured.Results show that,under salt and alkali stress,N.sibirica roots exhibited higher capacities to limit Na+influx and reduce K+efflux,thereby resulting in lower Na^(+)/K^(+)ratios compared with V.radiata roots.Alkali stress induced stronger Na^(+)influx and K+efflux in the root salt stress treatment;Na^(+)influx was mainly observed in the root cap,while K^(+)efflux was mainly observed in the elongation zone.While under osmotic stress,N.sibirica roots showed stronger Na+efflux and weaker K+efflux than V.radiata roots.Na+efflux was mainly observed in the root elongation zone,while K+efflux was in the root cap.These results reveal the ionic strategy of N.sibirica in response to transient salt,alkali,and osmotic stresses through the regulation of Na+/K+flux homeostasis.

Comparative genomics of widespread and narrow-range white-bellied rats in the Niviventer niviventer species complex sheds light on invasive rodent success

Widespread species that inhabit diverse environments possess large population sizes and exhibit a high capacity for environmental adaptation,thus enabling range expansion.In contrast,narrow-range species are confined to restricted geographical areas and are ecologically adapted to narrow environmental conditions,thus limiting their ability to expand into novel environments.However,the genomic mechanisms underlying the differentiation between closely related species with varying distribution ranges remain poorly understood.The Niviventer niviventer species complex(NNSC),consisting of highly abundant wild rats in Southeast Asia and China,offers an excellent opportunity to investigate these questions due to the presence of both widespread and narrow-range species that are phylogenetically closely related.In the present study,we combined ecological niche modeling with phylogenetic analysis,which suggested that sister species cannot be both widespread and dominant within the same geographical region.Moreover,by assessing heterozygosity,linkage disequilibrium decay,and Tajima's D analysis,we found that widespread species exhibited higher genetic diversity than narrow-range species.In addition,by exploring the“genomic islands of speciation”,we identified 13 genes in highly divergent regions that were shared by the two widespread species,distinguishing them from their narrow-range counterparts.Functional annotation analysis indicated that these genes are involved in nervous system development and regulation.The adaptive evolution of these genes likely played an important role in the speciation of these widespread species.

Serial Expression of the Truncated Fragments of the Nucleocapsid Protein of CCHFV and Identification of the Epitope Region

The Crimean-congo hemorrhagic fever virus(CCHFV)is a geographically widespread fatal pathogen. Identification of the epitope regions of the virus is important for the diagnosis and epidemiological studies of CCHFV infections.In this study,expression vectors carrying series truncated fragments of the NP(nucleocapsid protein)gene from the S fragment of CCHFV strain YL04057 were constructed.The recombinant proteins were expressed in E.coli and purified for detection.The antigenic of the truncated fragments of NP was detected with a polyclonal serum(rabbit)and 2 monoclonal(mAbs)(14B7 and 43E5)against CCHFV by Western-blot analyses. The results showed that the three expressed constructs,which all contained the region 235AA to 305AA could be detected by mAbs polyclonal serum.The results suggest that region 235-305 aa of NP is a highly antigenic region and is highly conserved in the NP protein.

Responses of soil inhabiting nitrogen-cycling microbial communities to wetland degradation on the Zoige Plateau,China

The wetlands on the Zoige Plateau have experienced serious degradation,with most of the original marsh being converted to marsh meadow or meadow.Based on the 3 wetland degradation stages,we determined the effects of wetland degradation on the structure and relative abundance of nitrogencycling(nitrogen-fixing,ammonia-oxidizing,and denitrifying) microbial communities in 3 soil types(intact wetland:marsh soil;early degrading wetland:marsh meadow soil;and degraded wetland:meadow soil) using 454-pyrosequencing.The structure and relative abundance of nitrogen-cycling microbial communities differed in the 3 soil types.Proteobacteria was the predominant phylum in most soil samples but the most abundant soil nitrogenfixing and denitrifying microbial bacteria differed at the class,order,family,and genus levels among the 3soil types.At the genus level,the majority of nitrogenfixing bacterium sequences related to Bradyrhizobium were from marsh and marsh meadow soils;whereas those related to Geobacter originated from meadow soil.The majority of ammonia-oxidizing bacterium sequences related to Nitrosospira were from marsh(except for the 40-60 cm layer),marsh meadow and meadow soils;whereas those related to Candidatus Solibacter originated from 40-60 cm layer of marsh soil.The majority of denitrifying bacterium sequences related to Candidatus Solibacter and Anaeromyxobacter were from marsh and meadow soils;whereas those related to Herbaspirillum originated from meadow soil.The distribution of operational taxonomic units(OTUs)and species were correlated with soil type based upon Venn and Principal Coordinates Analysis(PCoA).Changes in soil type,caused by different water regimes were the most important factors influencing compositional changes in the nitrogen-fixing,ammonia-oxidizing,and denitrifying microbial communities.

Isolation of protoplast from callus of Populus euphratica and H^+ fluxes across plasma membrane under NaCl stress

We used callus of Populus euphratica Olive to isolate protoplasts, and IT fluxes across plasma membrane were investigated. The concentration of enzymes for protoplast isolation, e.g. cellulase, pectolyase, macerozyme, hemicellulase, and sorbitol content, incubation time were systemically studied. High yield and viability of protoplast was achieved after 6-8 hours incubation of P. euphratica callus in enzyme solution containing 1.5% （w：v） cellulase R-10, 0.1% （w：v） pectolyase Y-23, 0.2% （w：v） macerozyme R-10, 0.05% （w：v） hemicellulase and 0.75M）.80 mol·L^-1 sorbitol. Non-invasively ion selective microelectrode technique was used to access proton fluxes in the absence and presence of NaCl （20 mmol.L-1）. Salt-induced transient net IT effiux was observed in the plasma membrane ofP. euphratica cells. The shift of IT flux response to NaC1 shock and the relevance to salt tolerance were discussed.

Biosorption behavior and mechanism of thorium on Bacillus sp. dwc-2 isolated from soil

To develop a microbe-based bioremediation strategy for cleaning up thorium-contaminated sites, we have investigated the biosorption behavior and mechanism of thorium on Bacillus sp. dwc-2, one of the dominant species of bacterial groups isolated from soils in Southwest China. Thorium biosorption depended on the p H of environment, and its rapid biosorption reached a maximum of up to 10.75 mg Th per gram of the bacteria(wet wt.) at pH 3.0. The biosorption agreed bettter with Langmuir isotherm model than Freundlich model, indicating that thorium biosorption was a monolayer adsorption. The thermodynamic parameters, negative change in Gibbs free energy and positive value in enthalpy and entropy, suggested that the biosorption was spontaneous,more favorable at higher temperature and endothermic process with an increase of entropy. Scanning electron microscopy(SEM) indicated that thorium initially binded with the cell surface, while transmission electron microscopy(TEM) revealed that Th deposited in the cytoplasm and served as cores for growth of element precipitation(e.g., phosphate minerals) or by self-precipitation of hydroxides, which is probably controlled by ion-exchange, as evidenced by particle induced X-ray emission(PIXE) and enhanced proton backscattering spectrometry(EPBS). Fourier Transform Infrared(FTIR) further indicated that thorium biosorption involved carboxyl and phosphate groups and protein in complexation or electrostatic interaction. Overall results indicated that a combined electrostatic interaction-complexation-ion exchange mechanism could be involved in thorium biosorption by Bacillus sp. dwc-2.

Synthesis, Crystal Structure and Antitumor Activity of N-[5-(Benzylthio)-1,3,4-thiadiazol-2-yl]-4-chlorobenzamide

The title compound N-[5-（benzylthio）-1,3,4-thiadiazol-2-yl]-4-chlorobenzamide（C（16）H（12）ClN3OS2, Mr = 361.86） was designed and synthesized as anticancer agent, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to triclinic, space group P1 with a = 5.7417（10）, b = 9.8057（17）, c = 14.330（3） A, a = 91.987（3）, b = 97.154（3）, γ = 93.402（3）°, V = 798.4（2） A3, Z = 2, Dc = 1.505 g/cm^3, μ = 0.507 mm-1） F（000） = 372, the final R = 0.0481 and wR = 0.1290 for 2064 observed reflections with I 〉 2s（I）. In the crystal packing, the molecules form stacks by a three-dimensional framework, which results from intermolecular N（1）-H（1）···N（2） and C（5）-H（5）···N（3） hydrogen bonds together with π-π stacking interactions between the thiadiazole and chlorobenzene rings. The title compound was found to exhibit more potent in vitro antitumor activities against the four tested cancer cell lines than sorafenib.

Synthesis, Crystal Structure and Bioactivities of 1-(4-Chlorophenyl)-3-[5-(pyrid-4-yl)-1,3,4-thiadiazol-2-yl]urea

The title compound 1-（4-chlorophenyl）-3-[5-（pyrid-4-yl）-1,3,4-thiadiazol-2-yl]urea （C14H10CIN5OS, Mr = 331.79） has been synthesized by the reaction of 2-amino-5-（pyrid-4-yl）- 1,3,4-thiadiazole with 4-chlorobenzoyl azide, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to triclinic system, space group PI with a = 5.8550（8）, b = 7.5668（10）, c = 16.416（2）A, α= 78.364（2）, β= 81.204（2）, γ= 84.749（2）°, V= 702.58（16）A^3, Z= 2, Dc = 1.568 g/cm^3, p = 0.429 mm ^-1, F（000） = 340, the final R = 0.0442 and wR = 0.1092 for 2001 observed reflections （1 〉 2σ（I））. X-ray diffraction analysis reveals that the title molecule is nearly planar. In the crystal structure, the molecules are linked by strong intermolecular N-H…N hydrogen bonds together with weak nonclassical intennolccular （C-H…Y, Y = N, O and CI） hydrogen bonds and stacked through π-π interactions. The preliminary bioassay shows that the title compound exhibits good fungicidal activities against Rhizoctonia solani, Botrytis cinerea and Dothiorella gregaria.

The Potassium Transporter AtKUP12 Enhances Tolerance to Salt Stress through the Maintenance of the K^(+)/Na^(+)Ratio in Arabidopsis

Potassium(K^(+))is a necessary nutrient for plant growth and crop production.The K^(+)transporter plays crucial roles in the absorption and transport of K^(+)in plants.Most K^(+)transporters in Arabidopsis have been reported,but AtKUP12,which is a member of the KT/KUP/HAK family,has not yet been the subject of relevant in-depth research.In the present study,we demonstrated that AtKUP12 plays a crucial role in K^(+)uptake in Arabidopsis under 100μM low-K^(+)and 125 mM salt stress conditions.AtKUP12 transcripts were induced by K^(+)deficiency and salt stress.We analyzed the K^(+)uptake of AtKUP12 using the K^(+)uptake-deficient yeast R5421 and Arabidopsis mutant atkup12.Transformation with AtKUP12 rescued the growth defect of mutant yeast and atkup12 mutant plants at the low-K^(+)concentration,which suggested that AtKUP12 might be involved in high-affinity K^(+)uptake in low-K^(+)environments.In comparison to the wild-type(WT)and atkup12-AtKUP12 complementation lines,atkup12 showed a dramatic reduction in potassium concentration,K^(+)/Na^(+)ratio,and root and shoot growth on 12-day-old seedlings under the salt conditions;however,there was no significant difference between the complementation and WT lines.Taken together,these results demonstrate that AtKUP12 might participate in salt tolerance in Arabidopsis through K^(+)uptake and K^(+)/Na^(+)homeostasis.

Effect of NaCl on growth and ion relations in two salt-tolerant strains of Paxillus involutus

The effect of NaCl on growth, biomass and ion relations of two salt-tolerant isolates of Paxillus involutus, MAJ and NAU were investigated. The two Paxillus strains were exposed to the following concentrations of NaCl： 0, 100, 200 and 500 mmol·L^-1. Growth of MAJ and NAU was enhanced by 100 mmol·L^-1 NaCl but severely inhibited at the concentration of 500 mmol·L^-1. NAU exhibited a greater capacity to exclude Na^＋ and Cl^- under all salinity levels, whereas the salt-includer MAJ had a higher capacity in nutrient uptake under salt stress. The ratios Na^＋/K^＋, Na^＋/Ca^2＋ and Na^＋/Mg^2＋ in NaCl-treated MAJ and NAU did not increase at levels of 100 and 200 mmol·L^-1 NaCl but markedly increased at 500 mmol·L^-1. This suggests that the two strains, especially MAJ, enhanced nutrient uptake corresponding to the increased Na^＋ influx at moderate salinity. We conclude that both MAJ and NAU are able to tolerate 500 mmol·L^-1 NaCl but there are species-specific differences in retaining ionic homeostasis in the two Paxillus strains. NAU is a salt-excluder, MAJ is a salt-includer but retains a high capacity in nutrient selectivity under saline conditions. Their definite mechanisms to enhance salt tolerance of mycorrhizal hosts need further study.

Predominating stable adsorption and direct electrochemistry of glucose oxidase on carbon nanotubes by oxygen-containing groups

Stable adsorption and direct electrochemistry of glucose oxidase （COx） occurred on nitric acid （HNO3）-treated multi-walled carbon nanotubcs （MWNTs） instead of as-received MWNTs, demonstrating the critical roles of oxygen-containing groups in stable adsorption and direct electrochemistry of GOx on carbon nanotubcs （CNTs）.

Short-term transcriptomic responses of Populus euphratica roots and leaves to drought stress

Populus euphratica Oliv.,the Euphrates poplar,is the tallest tree species in the arid desert areas of Northwest China.Investigation of its drought-resistance genes is valuable to increase understanding of drought resistance mechanisms.RNA-seq of leaves and roots under drought simulation by 25%polyethylene glycol-6000(PEG 6000)were performed at 0,4,and 12 h.Leaves and roots responded differently to drought via differentially upregulated and downregulated genes;more genes were downregulated than upregulated in both leaves and roots.Additionally,these differentially expressed genes were enriched in different GO terms and KEGG pathways.For example,GO term‘response to organic substance’and KEGG pathway‘nitrogen metabolism’were enriched for drought-stressed leaves,while GO term‘cell wall organization or biogenesis’and KEGG pathway‘zeatin biosynthesis’were enriched for drought-stressed roots.The enrichment of the GO term‘enzyme linked receptor protein signalling pathway’in both leaf and root drought responses suggests that these tissues may also have similar mechanisms.However,roots under drought stress for four hs responded by activating programed cell death.The KEGG pathway‘plant hormone signal transduction’was detected for 4-and 12-h droughtstressed leaves and 12-h drought-stressed roots,suggesting that plant hormone signal transduction plays an important role in both roots and leaves.GO enrichment of upregulated and downregulated genes for leaves and roots reflect differentially regulatory mechanisms of response to drought stress via different biological processes such as the regulation of photosynthesis and auxin signalling pathway in leaves,and the regulation of defence response and water homeostasis in roots.Fifteen candidate genes,including transcription factors,protein kinase,transporter,late embryogenesis abundant protein and mannitol dehydrogenase,were further selected to determine their response to drought using qRTPCR.The results show that the expression patterns of 13 of the 15 genes correspond to the RNA-seq results.This study provides new insights into the drought response mechanism of P.euphratica and suggests new candidate gene resources.

Pollination adaptations of group-by-group stamen movement in a meadow plant with temporal floral closure

Floral sexual organ(stamen and pistil)movements are selective adaptations that have different functions in male-female reproduction and the evolution of flowering plants.However,the significance of stamen movements in the spatialetemporal function and separation of male and female organs has not been experimentally determined in species exhibiting floral temporal closure.The current study investigated the role of slow stamen(group-by-group)movement in male-female sexual function,and the effect of stamen movement on pollen removal,male-male and male-female interference,and mating patterns of Geranium pratense,a plant with temporal floral closure.This species uses stamen group-by-group movement and therefore anther-stigma spatialetemporal separation.Spatial separation(two whorls of stamen and pistil length)was shown to be stronger than temporal separation.We found that stamen movements to the center of the flower increase pollen removal,and the most common pollinators visited more frequently and for longer durations during the male floral stage than during the female floral stage.Petal movements increased both self-pollen deposition rate and sexual interference in G.pratense.The fruit and seed set of naturally and outcrossed pollinated flowers were more prolific than those of selfpollinated flowers.Group-by-group stamen movement,dehiscence of stamens,pistil movement,and male-female spatialetemporal functional separation of G.pratense before floral temporal closure may prevent male-female and stamen-stamen interference and pollen discounting,and may increase pollen removal and cross-pollination.

Salt-induced hydrogen peroxide is involved in modulation of antioxidant enzymes in cotton

Salt severely restricts cotton(Gossypium hirsutum) growth and production.The present study was undertaken to study the effect of salt-induced hydrogen peroxide(H_2O_2) on antioxidant enzymes in cotton.Na Cl treatment or exogenous H_2O_2 was used to investigate the relationship between H_2O_2 content and levels of antioxidant enzymes including superoxide dismutase(SOD),ascorbate peroxidase(APX),peroxidase(POD),and catalase(CAT),as well as the transcriptional levels of corresponding genes.H_2O_2 content increased within 24 h following 200 mmol L^(–1)Na Cl treatment.Both Na Cl-induced and exogenous H_2O_2 increased the activity of antioxidant enzymes including APX and SOD and upregulated the transcriptional levels of Ghc APX1,Gh Fe SOD,and Ghchl CSD.These increased activities and upregulated transcriptional levels were inhibited when the salt-induced H_2O_2 was scavenged by NAC.These results indicate that salt-induced H_2O_2 as a second signaling messenger modulates APX and SOD activities by regulating the transcription levels of corresponding genes,alleviating oxidative stress,and increasing salt tolerance in cotton.

Synthesis, Crystal Structure and Flame Retardance of 2-(3-Silatranylpropylamino)-4-phenyl-5,5-dimethyl-1,3,2-dioxaphosphorinane-2-oxide

The title compound, 2-（3-silatranylpropylamino）-4-dichlorophenyl-5,5-dimethyl- 1,3,2-dioxaphosphorinane-2-oxide （2（C20H33N2O6Psi）？C2H6O？CH4O, Mr = 991.20）, has been synthe- sized by the nucleophilic substitution reaction of 2-chloro-4-phenyl-5,5-dimethyl-1,3,2-dioxa- phosphorinane-2-oxide with γ-aminopropylsilatrane, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P with a = 10.3783（15）, b = 11.2402（17）, c = 12.1675（18） ？, ？ = 70.653（4）, ？ = 82.908（4）, ？ = 85.690（4）？, V = 1328.1（3） ？3, Z = 1, Dc = 1.239 g/cm3, μ = 0.19 mm？1, F（000） = 532, the final R = 0.0640 and wR = 0.2090 for 3615 observed reflections with I 〉 2？（I）. The cyclic dioxaphosphorinane ring in the molecule adopts a thermodynamically stable cis conformation, while the silatrane fragment forms a cage-like structure in which there exists an intramolecular Si？N donor-acceptor bond. In the crystal structure, centrosymmetrically related molecules are linked by pairs of N–H？？？O hydrogen bonds into dimers, generating rings with graph-set motif R22（8）. Furthermore, a couple of O（7）–H（10）？？？O（3） hydrogen bonds were formed by O atom of P=O and H atom from hydroxyl in the solvent ethanol. Thermal property of the compound was also studied by means of thermogravimetry （TGA）. The thermal analysis and preliminary fireproofing test show that the title compound has good flame retardance.