Wild soybean(Glycine soja)transcription factor GsWRKY40 plays positive roles in plant salt tolerance

Wild soybean(Glycine soja),a relative of cultivated soybean,shows high adaptability to adverse environmental conditions.We identified and characterized a wild soybean transcription factor gene,GsWRKY40,that promotes plant salt stress.GsWRKY40 was highly expressed in wild soybean roots and was up-regulated by salt treatment.GsWRKY40 was localized in nucleus and demonstrated DNA-binding activities but without transcriptional activation.Mutation and overexpression of GsWRKY40 altered salt tolerance of Arabidopsis plants.To understand the molecular mechanism of GsWRKY40 in regulating plant salt resistance,we screened a cDNA library and identified a GsWRKY40 interacting protein GsbHLH92 by using yeast two-hybrid approach.The physical interaction of GsWRKY40 and GsbHLH92 was confirmed by co-immunoprecipitation(co-IP),GST pull-down,and bimolecular fluorescence complementation(BiFC)techniques.Intriguingly,co-overexpression of GsWRKY40 and GsbHLH92 resulted in higher salt tolerance and lower ROS levels than overexpression of GsWRKY40 or GsbHLH92 in composite soybean plants,suggesting that GsWRKY40 and GsbHLH92 may synergistically regulate plant salt resistance through inhibiting ROS production.qRT-PCR data indicated that the expression level of GmSPOD1 gene encoding peroxidase was cooperatively regulated by GsWRKY40 and GsbHLH92,which was confirmed by using a dual luciferase report system and yeast one-hybrid experiment.Our study reveals a pathway that GsWRKY40 and GsbHLH92 collaboratively up-regulate plant salt resistance through impeding GmSPOD1 expression and reducing ROS levels,providing a novel perspective on the regulatory mechanisms underlying plant tolerance to abiotic stresses.

Analysis of Occurrence and Mixed Infection of Sugarcane Bacilliform Virus Disease in Hainan Sugarcane-growing Area

[Objectives]The paper was to explore the occurrence and mixed infection of sugarcane bacilliform virus disease in Hainan sugarcane-growing area.[Methods]A total of 348 sugarcane leaf samples were collected from 7 sugarcane-growing areas in Hainan Province.Molecular detection of sugarcane bacilliform virus(SCBV)was carried out by PCR using specific primers.[Results]SCBV was detected in 244 out of 348 sugarcane samples,with an average detection rate of 70.11%.The highest detection rate was 76.66%in the Danzhou sugarcane-growing area,while the lowest was 57.14%in the Baisha sugarcane-growing area.The SCBV-positive samples were subjected to testing for SCYLV,SCSMV,SrMV,and SCMV,respectively.The results indicated that 106 out of 244 positive samples exhibited a single infection with SCBV,while 138 samples exhibited mixed infections with SCBV and other sugarcane viruses.The proportion of mixed infections among the SCBV-positive samples was as high as 56.56%.Among the various types of mixed infections,two-virus and three-virus mixed infections were the most prevalent.[Conclusions]SCBV has emerged as a significant threat to the secure production of sugarcane in the Hainan sugarcane-growing region.It presents an explosive infection in the Hainan sugarcane-growing region and frequently combines with other sugarcane viruses to infect sugarcane.The findings of this study will provide a theoretical foundation for the prevention and control of sugarcane bacilliform virus disease.

Spray Effect on the Thermal Performances of a Dry Cooling Tower

Pre-cooling the inlet air of a dry cooling tower by means of a spray can improve the tower performance during periods of high temperature.To study the spray effect on the thermal performance of natural draft dry cooling towers(NDDCTs),in this study 3-D numerical simulations of such a process have been conducted using Fluent 16.2(a two-way coupled Eulerian-Lagrangian approach).The considered NDDCT is 120 m high and only half system is simulated due to its structural symmetry.Three different spray strategies have been investigated at a typical crosswind speed of 4 m/s,which is the most frequent wind speed.The results have shown that:(1)The three implemented spray strategies can improve the thermal performance of the studied NDDCT with a vary-ing degree of success.In one case,the heat rejection rate can be increased by 35.2%,and the tower outlet water temperature can be decreased by 2.1℃ when compared with the no spray case;(2)To improve the thermal per-formance of the NDDCT using a small amount of water,the design of the spray pre-cooling system must include more nozzles on the windward and fewer or even no nozzles on the leeward sides of the NDDCT.

Up-regulation of divalent metal transporter 1 in 6-hydroxydopamine intoxication is IRE/IRP dependent

Iron plays a key role in Parkinson＇s disease （PD）. Increased iron content of the substantia nigra （SN） has been found in PD patients, and divalent metal transporter 1 （DMT1） has been shown to be up-regulated in the SN of both MPTP-induced PD models and PD patients. However, the mechanisms underlying DMT1 up-regulation are largely unknown. In the present study, we observed that in the SN of 6-hydroxydopamine （6-OHDA）-induced PD rats, DMT1 with the iron responsive element （IRE, DMTI＋IRE）, but not DMT1 without IRE （DMTI-IRE）, was up- regulated, suggesting that increased DMTI＋IRE expression might account for nigral iron accumulation in PD rats. This possibility was further assessed in an in vitro study using 6-OHDA-treated and DMTl＋IRE-over-expressing MES23.5 cells. In 6-OHDA-treated MES23.5 cells, increased iron regulatory protein （IRP） 1 and IRP2 expression was observed, while silencing of IRPs dramatically diminished 6-OHDA-indueed DMTI＋IRE up-regulation. Pre- treatment with N-acetyl-L-cysteine fully suppressed IRPs up-regulation by inhibition of 6-OHDA-indueed oxidative stress. Increased DMTI＋IRE expression resulted in increased iron influx by MES23.5 cells. Our data provide direct evidence that DMTI＋IRE up-regulation can account for IRE/IRP-dependent 6-OHDA-induced iron accumulation initiated by 6-OHDA-induced intracellular oxidative stress and that increased levels of intracellular iron result in ag- gravated oxidative stress. The results of this study provide novel evidence supporting the use of anti-oxidants in the treatment of PD, with the goal of inhibiting iron accumulation by regulation of DMT1 expression.

Study on Sugarcane Smut

The pathogen and characteristics, infection cycle, occurrence regularity and damage symptoms of sugarcane smut were introduced in the paper. Moreover, the comprehensive prevention measures were proposed on the basis of planting disease-resistant species, strengthening cultivation managements to improve dis- ease-resistant ability of sugarcane, and adopting fungicide control as assistant measures. The study provided certain basis for reducing damages of sugarcane smut and imorovin yield and quality of sugarcane.

Study on Acute Toxicity of Purified Protein HAS1 Expression in KM Mice

[Objectives]The antifungal protein HAS1 newly obtained was evaluated for acute toxicity safety in KM mice according to relevant national regulations,so as to eliminate people s concerns about the safety of transgenic plants.[Methods]The acute toxicity of the purified protein HAS1 was observed by intragastric administration of mice,and the poisoning symptoms,poisoning degree,recovery and death were observed.[Results]No abnormal toxicity symptoms were observed in the test group,the vehicle control group and the blank control group.The main tissues and organs were not abnormal in gross anatomy.The average body weight of each group showed an increasing trend compared with before administration at 1,3,7,11 and 14 d after administration.It was found that after giving the purified protein HAS1 to KM mice at a cumulative dose of 64 mg/kg a day,no obvious toxicity was observed in the acute toxicity test,indicating that the test substance was non-toxic by oral administration.[Conclusions]This study provides a basis for further use of the protein and its coding genes.

Isolation,Screening and Identification of Antagonistic Actinomycetes against Ustilago scitaminea Syd

[Objectives] This study was conducted to obtain actinomycetes strains having antagonistic effect on Ustilago scitaminea Syd.[Methods] At first, actinomycetes strains were isolated from 22 soil samples in Hainan sugarcane regions. Then, antagonistic actinomycetes against U. scitaminea were screened by confrontation culture. Finally, the taxonomic status of antagonistic actinomycetes was determined using 16S rDNA.[Results] From the 22 samples, 984 actinomycetes strains were isolated. From all the isolated strains, 23 antagonistic actinomycetes strains were obtained through primary screening, and one strains with better antagonistic effect was then obtained through secondary screening, and designated FAS. 16S rDNA identification showed that strain FAS shared 99% sequence similarity with Streptomyces cealestis US24. A phylogenetic tree was built with MAGE 7.0 software, and the results showed that strain FAS had the shortest genetic distance with S. caelestis US24. Therefore, the actinomycetes FAS was determined as S. caelestis .[Conclusions] This study provides a new biocontrol method for the biological control of sugarcane smut, thereby ensuring sustainable development of sugarcane industry and sugar industry.

雷替曲塞/贝伐珠单抗联合伊立替康或奥沙利铂方案治疗晚期结直肠癌的临床研究(英文)

Objective: The aim of the study was to investigate the efficacy and safety of raltitrexed/bevacizumab in combination with irinotecan or oxaliplation for advanced colorectal cancer as the second-line and second-line above treatments. Methods: Fifteen cases of advanced colorectal cancer were enrolled to receive regimens including raltitrexed/bevacizumab combined with irinotecan or oxaliplation. Two cases were treated with raltitrexed + bavacizumab regimen, 9 cases with raltitrexed + bavacizumab + irinotecan regimen, and 4 cases with raltitrexed + bevacizumab + oxaliplation regimen. The doses of the drugs were as follows: bevacizumab 5 mg/kg ivgtt, d1; raltitrexed 2.0 mg/m2 ivgtt 15 min, d2; irinotecan 180 mg/m2 ivgtt 1 h, d2; and oxaliplatin 85 mg/m2 ivgtt 2 h, d2. Two weeks was a cycle for each regimen. Results: The efficacy of the 15 patients could be evaluated. Two cases were in PR,10 cases in SD, 3 cases in PD, the response rate was 13.3%, and the disease control rate was 80.0%. The median progress-free survival was 5.1 months(95% CI: 3.404–6.813 months), and the median overall survival was 11.5 months(95% CI: 8.985–13.930 months). The adverse effects included anorexia, nausea/vomiting, fatigue, leucopenia, thrombocytopenia, etc, and the main 3–4 grades adverse effects were anorexia, nausea/vomiting, fatigue, and thrombocytopenia. Conclusion: Raltitrexed/bevacizumab combined with irinotecan or oxaliplatin as the secondline and second-line above treatments for advanced colorectal cancer has high disease control rates, and the adverse effect is well tolerated. The combined regimen can be recommended as a phase III clinical research and second-line and secondlines above treatments for advanced colorectal cancer.

Skin Anaphylaxis Test of Purified Protein HAS1 in Cavies

The antifungal protein HAS1 is a new antifungal protein isolated from the genome of Bacillus subtilis HAS,which has a good inhibitory effect on various pathogenic fungi in sugarcane.This study aimed at evaluating the immunological transfer reaction of the test sample through repeated skin contact by observing whether the cavy skin repeatedly exposed to purified protein HAS1 suffers from allergic reaction and how strong is the allergic reaction.The results showed that the test group and the vehicle control group exhibited no allergic reaction in the skin immediately and at 24,48 and 72 h and had an mean reaction score and a sensitization rate both of 0,so the results of the naked eye observation were both nonallergenic to cavy skin;and in the positive control group,the cavies were observed to be highly sensitized immediately after removing the drug,mildly sensitized at 24 h,and not sensitized at 48 and 72 h,which meant the skin allergy was alleviated with the observation time.It is suggested that the purified protein HAS1 is negative for cavy skin anaphylaxis test (nonallergenic to cavy skin),which provides an experimental basis for further utilization of the protein and its coding gene.

Research Progresses on Sucrose Accumulation and Genetic Improvement in Sugarcane

Sugarcane is an important sugar and energy crop in tropical areas. Sucrose is the main product of photosynthesis and the end accumulation carbohydrate.The sucrose accumulation mechanism in sugarcane is typical in plants. We summarized the new progresses of molecular mechanisms on sucrose accumulation in sugarcane and the genetic improvements on sugar trait by genetic modification techniques. In addition,the developments of genetic modification techniques were also concluded.

Construction and optimization of a base editor based on the MS2 system

Background:Catalytic defect Cas9‐cytosine deaminase fusion is widely used in base editing.The Multiple copy numbers of the MS2 binding site(MBS)can recruit multiple MS2 coat proteins(MCPs),which are usually applied to amplify signals.Our study aimed to apply the MS2 signal amplification system to the base editing system in order to achieve simultaneous mutations of multiple bases at the target genome site.Methods:Multiple copy numbers of the MS2 were ligated to the 3′‐end of sgRNA,and MCP was fused to the 5′‐end of cytosine deaminases.The MS2 was recognized by MCP to recruit cytosine deaminase for base substitutions(C‐T)at the target site.Different Cas9 variants,different cytosine deaminases and different copy numbers of MS2 were tested in this system,and the different versions of base editors were compared by editing efficiency and window.Results:In this study,dCas9,nCas9(D10A)and nCas9(H840A)were used.Among these 3 Cas9 variants,dCas9 exhibited higher base mutation efficiency.Two cytosine deaminases were then applied and the efficiency of rAPOBEC1 deaminase was found to be higher than AID.We also increased the copy numbers of MS2 linked to sgRNA from 2 to 12.Disappointingly,the sgRNA‐12x MS2 did not improve the editing efficiency or increase the editing window.Conclusion:An optimal version of base editor based on the MS2 system,MS2‐BErAPOBEC1(sgRNA‐2x MS2,MCP‐rAPOBEC1 and dCas9),was obtained.This tool can simultaneously mutate multiple bases at the target site,providing a new approach for the study of genome functions.

Cloning and Analysis of TasA Gene in Bacillus subtilis HAS

In order to clarify the mechanism for the inhibitory action of the Bacillus subtilis strain HAS on Sporisorium scitamineum （ Syd. ）, which can cause sugarcane smut, the full-length TasA gene which encodes a protein with broad-spectrum antimicrobial activity, was PCR-amplified from HAS, and cloned into pMD18-T vector. Sequence analysis indicated that the full-length TasA cloned from HAS consisted of 786 nucleotides, and shared 99% homology in nucleotide sequence with the TasA gene sequence published in Genbank （AJ871386.1）. It was predicted that the molecular weight of TasA protein was about 28 kD. Base transitions or transversions ~curred at positions 104, 164, 169,250, 399,623 and 627, at the 2nd, 2nd, 3rd , 1st , 3rd, 2nd and 3rd bases of TasA codons. The mutations in the seven bases may cause the missense mutations of the polypeptide chain. Compared with the amino acid sequences of the TasA protein encoded by Bacillus aubtilis subsp, subtilis str. 168, mutations in two amino acids at positions 150 and 209 of the protein encoded by the cloned TasA gene were found, and as a result, an ala- nine was replaced with a threonine.

Expression of Invertase Genes in Virus-free Sugarcane

Virus-free sugarcane seedlings have improved biomass and sucrose content compared with ordinary seedlings, and sucrose invertases are key enzymes regulating sugarcane growth and sucrose accumulation. In this study, the differences in the expression levels of 3 invertase genes, CWI, SAI and NI, between virus- free and ordinary sugarcane seedlings were analyzed. Compared with ordinary sugarcane plants, the expression of CWI was mainly up-regulated in immature leaves and stems at elongation stage and leaves and immature internodes at maturation stage, and especially, greatly up-regulated in immature interuedes at maturation stage of virus-free plants. The expression of SAI and NI were mainly up-regnlated in leaves and immature internedes of virus-free plants at maturation stage, which might be beneficial to sugar accumulation and rapid utilization of monosaccharide in the stalks of virus-free plants. It is further indicated that virus-free treatment could significantly improve the expression of sucrose invertases at late growth period, and might facilitate the increase of plant biomass.

Polyploidization Genetic Mechanism of Sugarcane Genome

The sugarcane genome polyploidization can reduce the pressure of gene evolution selection,promote the fixation of fine traits,and increase the biomass and economic value of sugarcane.This paper mainly introduced the origin of the sugarcane genome,the chromosome composition,the research progress of polyploidization genetic mechanism,in the hope of providing theoretical reference for sugarcane polyploidization breeding.

Optimization of Streptomyces caelestis Culture Conditions and Preliminarily Determination of Its Antifungal Components

Streptomyces caelestis FAS is an actinomyces strain isolated with Ustilago scitaminea as an indicator. With GAUZE s medium as the basic medium, carbon source and nitrogen source in the medium and ventilation volume were optimized, and the antifungal substances produced by S. caelestis FAS were preliminarily determined through organic solvent extraction and ammonium sulfate precipitation. The results showed that the antifungal components produced by S. caelestis FAS were proteins, and the optimal culture conditions were using corn flour as carbon source and KNO 3 as nitrogen source and culturing in 250 ml triangular flask added with 70 ml of culture medium. The crude protein obtained under these culture conditions had the best antifungal effect with an inhibition zone diameter of 25 mm. This study will provide a scientific basis for further study on the antifungal mechanism and application of S. caelestis FAS.

Study on Wide Antifungal Property of Bacillus subtilis HAS

Bacillus subtilis HAS is a biocontrol strain with better inhibitory effect on Sporisorium scitaminea Sydow. In order to further understand its action range,with fungal pathogens in sugarcane production as targets,confrontation tests and tests of inhibitory effect of secondary metabolites on growth of pathogens were carried out. The results showed that B. subtilis HAS not only had better inhibitory effect on S. Scitaminea,but also inhibited the growth of various fungal pathogens in sugarcane production. The inhibitory effect was the best on Ceratocystis adiposum,Thielaviopsis paradoxa,Fusarium moniliforme and Colletotrichum fuleatum,which was reflected by the radius of inhibitory zone over 10 mm. The inhibitory rates of the secondary metabolites were about 70%. It indicates that B. subtilis HAS has wide antifungal property,providing reference for further application of this strain.

Aged hematopoietic stem cells entrap regulatory T cells to create a prosurvival microenvironment

Although DNA mutation drives stem cell aging,how mutation-accumulated stem cells obtain clonal advantage during aging remains poorly understood.Here,using a mouse model of irradiation-induced premature aging and middle-aged mice,we show that DNA mutation accumulation in hematopoietic stem cells(HSCs)during aging upregulates their surface expression of major histocompatibility complex class II(MHCII).MHCII upregulation increases the chance for recognition by bone marrow(BM)-resident regulatory T cells(Tregs),resulting in their clonal expansion and accumulation in the HSC niche.On the basis of the establishment of connexin 43(Cx43)-mediated gap junctions,BM Tregs transfer cyclic adenosine monophosphate(cAMP)to aged HSCs to diminish apoptotic priming and promote their survival via activation of protein kinase A(PKA)signaling.Importantly,targeting the HSC–Treg interaction or depleting Tregs effectively prevents the premature/physiological aging of HSCs.These findings show that aged HSCs use an active self-protective mechanism by entrapping local Tregs to construct a prosurvival niche and obtain a clonal advantage.

Toxic effects of chlortetracycline on maize growth,reactive oxygen species generation and the antioxidant response

The toxicity of chlortetracycline （CTC） on maize （Zea mays L.） growth and reactive oxygen species （ROS） generation was studied.The root and shoot lengths and fresh weights of maize seedlings were inhibited by CTC treatment （p 〈 0.05）.Root length was more sensitive than other parameters with the EC 10 value of 0.064 mg/L.The spin trapping technique followed by electron paramagnetic resonance （EPR） analysis was used to quantify the ROS production.The ROS generated in maize roots after exposure to CTC was identified as hydroxyl radical （·OH）.The EPR signal intensity correlated positively with the logarithm of CTC concentrations exposed （p 〈 0.05）.The dynamic changes of malondialdehyde （MDA） contents and the antioxidative enzyme activities in maize roots were also determined.As compared to the control group,CTC was found to significantly increase MDA content.Treatment of maize roots with the ·OH scavenger sodium benzoate （SB） reduced the MDA content and enhanced the antioxidative enzyme activities.The results demonstrated the harmfulness of CTC at high dose to maize in the early developmental stage,and clarified that the inducement of ·OH is one of the mechanisms of CTC toxicity.

Simultaneous determination of brominated phenols in soils

Brominated phenols （BPs）, a widely used group of emerging flame retardants, are important environmental contaminants and exhibit endocrine disrupting potential. Method for simultaneous determination of tetrabromobisphenol A （TBBPA）, tribromophenol （TBP）, dibromophenols （DBPs） and monobromophenols （MBPs） in soils using gas chromatography-mass spectrometry analysis （GC/MS） was successfully developed. Cleanup methods for soil extracts including several solid-phase extraction cartridges and different elution solvents were compared and optimized. Florisil cartridge with dichloromethane as the elution reagent was selected for sample cleanup owing to its high and reproducible recoveries of the target analytes in soils. Derivatization conditions were tested and the optimal conditions were obtained with 20 μL silylation reagent at room temperature. The chromatographic separation was optimized with different columns and DB-XLB column was selected for its excellent separation of the analytes. The limits of detection for the target compounds were from 0.04 to 0.19 ng/g. Mean recoveries of the compounds from spiked soils exceeded 84% with a good reproducibility, excepting that the recovery of 2-bromophenol was relatively poor （lower than 55%） due to its instability. The developed method was applied to the determination of the BPs in the soils collected from e-waste sites. The contents of BPs in the soils were at ng/g levels with TBBPA and TBP the most frequently detected. To our knowledge, this is the first report for the simultaneous determination of TBBPA, TBP, DBPs and MBPs in soils.

Uptake, translocation, and debromination of polybrominated diphenyl ethers in maize

Uptake, translocation and debromination of three polybrominated diphenyl ethers （PBDEs）, BDE-28, -47 and -99, in maize were studied in a hydroponic experiment. Roots took up most of the PBDEs in the culture solutions and more highly brominated PBDEs had a stronger uptake capability. PBDEs were detected in the stems and leaves of maize after exposure but rarely detected in the blank control plants. Furthermore, PBDE concentrations decreased from roots to stems and then to leaves, and a very clear decreasing gradient was found in segments upwards along the stem. These altogether provide substantiating evidence for the acropetal translocation of PBDEs in maize. More highly brominated PBDEs were translocated with more difficulty. Radial translocation of PBDEs from nodes to sheath inside maize was also observed. Both acropetal and radial translocations were enhanced at higher transpiration rates, suggesting that PBDE transport was probably driven by the transpiration stream. Debromination of PBDEs occurred in all parts of the maize, and debromination patterns of different parent PBDEs and in different parts of a plant were similar but with some differences. This study for the first time provides direct evidence for the acropetal translocation of PBDEs within plants, elucidates the process of PBDE transport and clarifies the debromination products of PBDEs in maize.