Polybrominated diphenyl ethers (PBDEs) are man-made flame-retardant chemicals that are widely used to decrease the flammability of plastics, electronic appliances textiles and polyurethanes. Annually, more than 67 400 tons of PBDEs including penta-, octa-, and deca-BDE were produced. PBDEs can be incorporated into polymers without any covalent bonds to adjacent materials. Because of the widespread production and improper disposal of these polymers, PBDEs have been accumulated in the environment. The toxicity of PBDEs is variable for different congeners. Some of them show neurotoxic toxicity in mice and dioxin-like endocrine disruption. In spite of the accumulation of PBDEs in the environment, few remediation technologies have been investigated sufficiently. A few works of biological degradation of PBDEs have been done in recent years. An efficient diphenyl ether degrading bacterium strain DZ-3, which was able to utilize diphenyl ether as a sole source of carbon and energy under aerobic condition, was isolated from activated sludge of a wastewater treatment plant. The growth and degradation character of the strain were studied in order to offer some useful informations for the remediation of contamination. In addition to the diphenyl ether degrading bacterium DZ-3, the other bacterium strain CZ-3 was also isolated, which can’t degrade biphenyl ether. But the mixed cultures of the two strains could enhance the degradation of diphenyl ether compared with DZ-3 cultivation. Based on 16S rDNA gene sequencing, the strains DZ-3 and CZ-3 were identified as Sphingomonas sp. DZ-3 and Ochrobactrum sp. CZ-3. Mixture design was used to adjust the proportion of each strain and the optimal ratio of inoculation size was DZ-3∶CZ-3=2∶3 . Diphenyl ether degradation experiments using high performance liquid chromatograph (HPLC) showed that the strain DZ-3 could degrade 71% of diphenyl ether (initial concentration of 835 mg/L) within 6 days, while the mixture of DZ-3 and CZ-3 could degrade 90% within 4 days. To further investigate the degree of metal ions affecting the biodegradation of Sphingomonas sp. DZ-3, a background propagation artificial neural network (ANN) was used to conduct a sensitive analysis on the individual variables. The ANN model showed satisfactory fits for the experimental data. The results indicated that Mg2+ appeared to be the most important metal ion for the biodegradation of DZ-3 with a relative importance of 31.01% followed by Co2+ (25.45%), Ni2+(15.12%) in which Mg2+ had a positive effect on the degradation, while Co2+ and Ni2+ had negative ones. In addition, the strain DZ-3 even catabolized biphenyl and monobrominated diphenyl ether. Meanwhile, the degradation of biphenyl ether in the polluted soil added with the exterior microorganism was studied by lab simulation. In lab simulation, the degradation percentage of diphenyl ether by Ochrobactrum sp CZ-3 and Sphingomonas sp. DZ-3 was 71% within 3 days and 98% within 6 days. The degradation effect was significant indicating that the mixed culture had great potential for remediation of contaminated soil. In conclusion, the research on the characteristics of the diphenyl ether biodegradation can provide theoritical basis and experience about engineering application for bioremediation of diphenyl ether and PBDEs polluted sites.

Major royal jelly proteins (MRJPs) are the soluble proteins in royal jelly, which account for 82%90% of total royal jelly proteins. MRJPs are consisted of ten members, i.e. MRJP1-MRJP9 and MRJPψ, whose biological functions include enhancing cell proliferation, inducing differentiation, modulating immune responses, accelerating wound healing, etc. MRJP1 with 57 ku in molecular mass was found possessing proliferation-promoting activities, enhancing proliferation of primary cultured rat hepatocytes and increasing albumin production in the absence of serum. MRJPs could significantly stimulate the proliferation and growth of endothelial progenitor cells (EPC). The recombinant MRJP1 could significantly stimulate growth of Tn-5B-4 cell from Trichoplusia ni, and affect cell shape and adhesion to the substrate. Similar activities were also found in normal human neonatal skin fibroblasts NB1 RGB cell, MC3T3-E1 cell and Jurkat cell, etc. All these findings showed the potential of MRJPs in cell culture as cell growth factor. Besides, it seemed that MRJP1 could promote liver regeneration and might have a cytoprotective action on hepatocytes. Here, we used Chang’s liver cell from human as object to observe the proliferation action of MRJPs on the cell line, and to explore the potential of MRJPs substituting fetal bovine serum (FBS) as growth factor; the active mechanism of MRJPs was also investigated. MRJPs were extracted by centrifuging from fresh royal jelly.The optimum concentration was selected by MTT assaying of the proliferation rates of the cell (PRC) cultured with serum-free mediums containing 0.05, 0.1, 0.2, 0.3 and 0.5 mg/mL of MRJPs at 5th day. The possibility of MRJPs with optimum concentration (0.5 mg/mL ) to replace FBS was investigated via comparison of the effects on PRC at the 2nd day, 5th day and 8th day in both serum-free and serum-existing mediums with a positive control containing 10% FBS and a negative control containing 10% phosphate buffer solution (PBS). It was showed that MRJPs could only be used to culture the cell line when it was mixed with FBS. Then, the effects of different MRJPs/FBS (M/F) ratios (0/100, 30/70, 60/40, 90/10, 100/0) on PRC at the 2nd day, 5th day and 8th day were investigated, respectively. It was shown that the M/F ratios with 30/70 and 60/40 were better for PRC of the cell line in relative to the complete medium with 10% FBS (M/F=0/100). The cell cycle distributions of the cell line cultured with different M/F ratios (0/100, 30/70, 60/40, 100/0) were detected by flow cytometry. It was shown that the proliferation index (PI), S phase and G0/G1 phase of the cell in the medium with M/F of 60/40 at the 5th day were not significantly different from the cell in complete medium （P＞0.05）, indicating that MRJPs might promote DNA synthesizing in S phase or RNA and protein synthesizing in G0/G1 phase. In conclusion, MRJPs mixed with FBS are suggested partially to replace FBS to culture Chang’s liver cell line in practice.

Thermophilic bacterium, strain CHBT-1721 is the first thermophilic microorganism isolated from the hot spring of Bantang in Chaohu and phylogenetic analyzed preliminarily by us in this study, which provided local government with primary data and scientific basis for utilization of Bantang hot spring water and protection of biodiversity. Strain CHBT-1721 was classified based on morphological features, physiology and biochemistry determination, and sequencing of its 16S rRNA gene. The 16S rRNA gene sequences of all the thermophilic bacteria with valid published names isolated from hot springs of China (22 thermophilic bacteria) were downloaded from the GenBank. The phylogenetic diversity of strain CHBT-1721 compared with the other 22 thermophilic bacteria was studied by constructing the phylogenetic tree, aligning their 16S rRNA gene sequences and analyzing their 16S rRNA secondary structures. Strain CHBT-1721 was classified to the genus of Bacillus sp. Phylogenetic analysis showed that strain CHBT-1721 formed a cluster in the phylogenetic tree and had 94% similarity with Anoxybacillus vitaminiphilus 3nP4T in the phylogroup. A. vitaminiphilus 3nP4T, A. eryuanensis E-112T and A. tengchongensis T-11T (Anoxybacillus spp.) were also in the cluster. 16S rRNA secondary structures comparison in the same cluster also indicated that strain CHBT-1721 had a unique 16S rRNA secondary structure characteristic in helix 18. Strain CHBT-1721 and Anoxybacillus spp. had identical 16S rRNA gene sequences in helices 12 and 18, but not all of them had identical 16S rRNA secondary structures. This current study reveals the phylogenetic diversity of strain CHBT-1721 when compared with the other 22 thermophilic bacteria for the first time. We also report that the chemical and biological parameters of the hot spring water in Bantang are similar to those in Puge.

Chestnut blight, caused by Cryphonectria parasitica, is a destructive disease on chestnut trees as well as an important international disease in the world. At the end of the 19th century and the beginning of the 20th century, this pathogen dispersed rapidly and nearly killed all the American chestnut trees. Cryphonectria parasitica belongs to ascomycetes, which mainly caused considerable damage to species of genus Castanea, such as C. sativa, C. henryi, C. dentata, and so on. In recent years, the chestnut blight tends to be aggravated and has caused tremendous loss in the ecology and economy. The traditional detection methods for C. parasitica are time-consuming, tedious, laborious, low sensitivity and accuracy. However, previous studies also did not have a lot of detection reports about C. parasitica. Therefore, rapid and efficient detection of C. parasitica is essential for undertaking appropriate and timely disease management measures. In the present study, polymerase chain reaction (PCR) assay had been developed for accurate and sensitive detection of some plant pathogens, which are much faster and more specific than traditional detection methods. The objective of this study was to develop a sequence characterized amplified region (SCAR) marker and PCR detection of C. parasitica. Randomly amplified polymorphic DNA (RAPD) was used to detect DNA polymorphisms between C. parasitica and other strains, and the specific RAPD fragment of C. parasitica was purified and inserted into pMD19-T vector that was transformed into Escherichia coli and cloned and sequenced. Based on the sequence of the RAPD marker, SCAR primers and the nested-PCR primers were designed and synthesized. Then the specificity and sensitivity of primers were verified. The results showed that primer S494 generated a polymorphic pattern displaying a 1 400 bp DNA fragment (SCQ494) specific for C. parasitica, but not from any other strains tested. Based on the sequence of SCQ494, the specific SCAR primers CQ1/CQ2 and the nested-PCR primers CR1/CR2 were designed by the aid of the software Primer Premier 5.0. The regular PCR product of all strains of C. parasitica showed a unique fragment of 1 420 bp with primers CQ1/CQ2; the nested-PCR primers CR1/CR2 amplified only a unique 875 bp band from all C. parasitica and there was no amplification from other strains tested. The detection sensitivity with primer set CQ1/CQ2 was 3 pg/μL for genomic DNA of C. parasitica in 25 μL reaction solution. In contrast, nested-PCR with CQ1/CQ2 as the first round primers and CR1/CR2 as the second round primers increased sensitivity to 30 fg/μL for genomic DNA of C. parasitica. In addition, C. parasitica could be specifically detected by nested-PCR assay from diseased plant tissues collected from field and artificial inoculation branches. In conclusion, nested-PCR for detection of C. parasitica has been developed based on the use of a SCAR marker and has a great significance for the prevention and control of chestnut blight. This is the first report on generation of SCAR markers for detection of C. parasitica and the result of the study may provide an important reference for the detection of other phytopathogen.

Diaphorina citri may be the most serious pest of citrus worldwide, primarily because it is the vector of huanglongbing (HLB), one of the most destructive citrus diseases, and can damage citrus directly by feeding fresh shoots and cause citrus sooty mold disease. Currently, control of D. citri mainly depends on the chemical pesticides. However, pesticides abuse affects workers and food safety, causes the development of insecticide-resistant D. citri populations, and reduces populations of natural enemies in citrus orchards. Therefore, new approaches are needed to complement the existing management strategies against D. citri. Lecanicillium lecanii, formerly named Verticillium lecanii, is an entomopathogenic fungus with a remarkably wide host range, which can infect aphids, whiteflies, trips, plant hoppers and so on. Infection of L. lecanii against D. citri was firstly reported in 1980s. However, from then on, there is no further research such as biological characteristic and pathogenicity difference about this fungus. Therefore, in this study, genetic diversities of 19 L. lecanii strains from different hosts and geographical origins as well as their biological characteristics and pathogenicities against D. citri were determined and analyzed. This research aimed to understand the genetic diversity, pathogenicity difference and their relationships with geographical origins, host varieties and biological characteristics. Firstly, 19 L. lecanii strains from different hosts and geographical origins were characterized using randomly amplified polymorphic DNA (RAPD) analysis. Based on the RAPD results, a dendrogram was constructed using unweighted pair group method with arithmetic mean (UPGMA) by software NTSYS-pc version 2.1. Then, the ITS1-5.8S rDNA-ITS2 and β-tubulin genes of these L. lecanii strains were amplified and sequenced using primer sets ITS5/ITS4 and Bt2a/Bt2b, respectively. These sequences were aligned with software ClustalX 2.0, edited with software BioEdit 7.2.5, and finally a phylogenic tree was constructed using the neighbor-joining method by software MEGA 5.05. Besides, the biological characteristics of these strains such as mycelial growth rates, sporulation quantities, conidial germination rates and conidial sizes were also determined. Furthermore, the pathogenicities of these strains against D. citri were assayed, and the invasion process of strain ZJVL-A was observed under a dissecting microscope, a scanning electron microscope and a light microscope. The results showed that a total of 96 polymorphic bands were amplified using 7 random primers, and the size of the bands ranged from 0.23 kb. All the 19 L. lecanii strains were divided into 2 groups in the UPGMA dendrogram. Strain CGVL-11 was located alone in one group, while the other strains were clustered into another group. In the latter group, 18 strains were then divided into 2 subgroups. The ITS1-5.8S rDNA-ITS2 and β-tubulin gene sequences had been deposited in GenBank and their accession numbers were KJ598810KJ598828 and KJ598829KJ598847, respectively. The similarities of ITS1-5.8S rDNA-ITS2 and β-tubulin gene sequences were 98%100% and 96%100% with each other, and molecular variations existed within these nucleotide sequences. The phylogenetic tree based on ITS1-5.8S rDNA-ITS2 and β-tubulin sequences was consistent with the dendrogram generated through RAPD analysis. The mycelial growth rates, sporulation quantities, conidial germination rates and conidial sizes of these strains were remarkably different. The colony diameter was 4.252.85 cm after 10 d incubation, and the sporulation quantity was 0.10×1089.75×108 conidia/mL after 3 d incubation in PDB medium, and the conidial germination rate was 3.55%68.38% after 8 h incubation at 25 ℃, and the size of conidia was 4.05.0 μm in length and 1.41.7 μm in width. Conidia of L. lecanii strain ZJVL-A mainly distributed in the intersegmental fold, setal alveolus, anus, genital, and other fold or sunken regions on every tagmata. At 16 h post-inoculation, the conidia began to germinate and penetrated the cuticle of host. At 42 h post-inoculation, the hyphae invaded into haemocoel, proliferated abundantly and filled the entire haemocoel. Diaphorina citri was killed by the fungus after 54 h post-inoculation. After 60 h post-inoculation, the internal organs of host such as fat body, muscle tissue, digestive tract and ovary were invaded and progressively degraded. Finally, a large number of newly-developed conidia could be observed on the hyphae which covered the body surface of host. In conclusion, genetic diversities and pathogenicity differences exist in populations of L. lecanii. Moreover, their biological characteristics also show significant differences. However, they have no relationship with each other and with host varieties or geographical origins. The strain ZJVL-A maybe kill D. citri through secreting some toxins before the hyphae degrade the internal organs of host. This research lays a good foundation for further study on the pathogenic mechanism of L. lecanii against D. citri, and takes an important step towards developing and utilizing these entomopathogenic fungi for their potential to suppress D. citri populations.

Cytoplasmic male sterility （CMS） lines are the excellent materials for studying the cytoplasmic and nuclear cytoplasmic interaction and have important application and theoretical value for CMS research. Three-line hybrid seed production could not only reduce the trouble of manual emasculation and seed costs, but also protect the purity of hybrid seeds. Therefore, the production of hybrid seed using CMS lines has a great potential and market demand in the pepper production.With the continuous development of science and technology, proteomics has become an important tool to decipher the biological gene function and contribute to the plant breeding. Proteome analyses helped to explore the important plant genes, thus speeding up the process of plant breeding and genetics research. However, the current researchs on male sterile pepper were mostly concentrated in the physiological and biochemical indexes and the male sterile gene. The relevant report on CMS pepper protein was relatively less, and the research of sterile anther protein was even more rarely reported. Therefore, the aim of this study was to preliminarily identify the differences of cytology and proteomics involved in the peppers anther of CMS line and its maintainer line. The anthers at six different stages were used in the experiment. At first, the paraffin sections of anthers were observed and used to study the differences between CMS line and its maintainer line from the apparent characteristics, and then SDS-PAGE was used for anther protein separation and identification. Differential protein bands separated by SDS-PAGE, and the proteome profiles of the differential protein bands were further analyzed and identified by LC-MS/MS and proteomics analysis. The results showed that pollen abortion occurred after metaphase. The main reason was that the callose surrounding the tetrad didnt disintegrate normally and the tapetum cells were excessive vacuolation. One-dimensional SDS-PAGE analysis revealed that, compared with its maintainer line, there were four fewer protein bands in CMS line. A total of 64 non-redundant proteins were identified by LC-MS/MS, including 12 unique proteins from band 1, 9 unique proteins from band 2, 21 unique proteins from band 3, 18 unique proteins from band 4, and 2 proteins from both band 1 and band 3, 1 protein from both band 2 and band 3, 1 protein from both band 3 and band 4. Among them, 24 proteins were involved in catalysis according to molecular function; 20 proteins were involved in cell endometrial tissue according to cellular components; and 24 proteins were involved in the metabolic process according to biological processes. In conclusion, pepper CMS is mostly caused by pollen abortion. Pollen sterility is directly or indirectly related to abnormal tapetum and the lack of callose disintegration. After the differential proteome analysis between pepper CMS line and its maintainer line, we find that after metaphase, due to the decreased expression involving substance and energy metabolism in a part of the protein in the anther of male sterile line, the tapetum cells develop abnormally and the four separate microspores in development can not obtain matter and energy. Then pollen might be abortion. Therefore, in this study, the differential proteins identified by proteomics analysis can preliminarily explain the differences in cytology.

Rahnella aquatilis HX2, which was isolated from the vineyard soil, is a gram-negative, plant growth-promoting rhizobacteria. Previous results showed that R. aquatilis HX2 has significant antagonistic effect on certain pathogenic bacteria and fungi including Agrobacterium tumefaciens, Xanthomonas oryzae, Fusarium oxysporum, Botrytis cinerea, Altemaria solani, etc, and exhibited the potential biocontrol value against rice sheath blight and crown gall of grapevine and sunflower. The completed genomic DNA sequence of R. aquatilis HX2 has been finished. For further discovery of the regulatory systems which regulate its biocontrol and physiological traits, random mutagenesis based on mini-Tn5 transposon was used to investigate the regulatory genes. The candidated genes were focused on the regulatory function in biocontrol-related physiological traits and biocontrol effects. Consequently, a mutant TR57 which had less antagonitic effect against the plant pathogen Agrobacterium vitis K308 was obtained after the random mutagenesis based on mini-Tn5 transposon and antagonitic assay. The DNA sequence flanking the inserted mini-Tn5 transposon was verified as a BarA-liked histidine kinase gene. The putative BarA protein in R. aquatilis HX2 contains HAMP domain, HisKA domain, HATPase_C domain, REC domain and HPT domain. BarA has been reported as the sensor protein of a two-component regulatory system BarA/UvrY in many bacteria, such as Escherichia coli, Pseudomonas spp. and the BarA/UvrY was known as a global regulatory functioning in bacterial survival under the circumstance of pH value and nutrition change. For further investigation of BarA in R. aquatilis HX2, null barA mutant was constructed based on homologous recombination. A vector pSRΔbarA was constructed after inserting the flanking region of barA loci into the suicide vector pSR47S, and transformed into E. coli DH5α (λ-pir). The triparental mating strategy was used to transfer the vector pSRΔbarA into R. aquatilis HX2. After the two-step homologous recombination, the null barA mutant MR57 was obtained consequently. Meanwhile, the complemented vector pRKbarA was constructed after inserting the barA operon into the shuttle vector pRK415G, and then was transformed into MR57. The biocontrol-related physiological traits and biocontrol effect of R. aquatilis HX2 and its derivative strains were compared to valuate the barA regulation function. The experimental results indicated that the mutagenesis of barA caused higher bacterial biofilm formation ability, less swimming and swarming ability. The biocontrol efficiency of barA mutant against A. vitis K308 on grape plants decreased to 26.7%, comparing to 86.2% of the wild type strain. Moreover, the complemented strain could recover all the measured biological characters and bio-control efficiency. Therefore, it was supposed that the histidine kinase gene barA plays the key role in biocontrol function of R. aquatilis HX2. In summary, barA is firstly found as a regulation gene functioning in bacterial biocontrol effect in this study. The results also give us the indication that the modification of bacterial two-component regulation systems would be helpful to facilitate the application of biocontrol bacteria.

Exserohilum rostratum is one of the important pathogens causing banana leaf spots, which has a wide host range. The effects of carbon and nitrogen sources on colony diameters and sporulation among different isolates of E. rostratum have been analyzed using conventional variance analysis method; however, this method was impossible to differentiate the common carbon and nitrogen sources from the species and the isolate-specific ones for growth and sporulation. In-depth difference analyses of various carbon and nitrogen sources were performed to determine the nutritional characteristics of E. rostratum causing banana leaf spot disease, and to provide a basis for disease management. Three isolates (CLER09, D087 and JL05) of the pathogen were used as the experimental ones. The Czapeks medium was used as a basal medium for nutritional tests on carbon and nitrogen sources. The sucrose in the basal medium was substituted with an equal amount of each of the 20 carbon sources tested. The potassium nitrate in the basal medium was substituted with an equal amount of each of the 26 nitrogen sources tested. The basal medium lacking sucrose and that lacking potassium nitrate were used as the controls for carbon and nitrogen utilization tests, respectively. The three isolates were inoculated on the basal media containing different carbon and nitrogen sources at 28 ℃ for 4 days. The colony diameters and the numbers of conidia produced were separately investigated. The data obtained were evaluated using multiple statistical methods including cluster analysis, discriminatory analysis and comprehensive correlation analysis. The results indicated that the carbon sources had significant effect on growth and sporulation of isolates CLER09, D087 and JL05. Of the carbon sources tested, lactose was identified as the most suitable general carbon source for growth and sporulation of the three isolates. Maltose, sucrose, glucose, α-lactose, xylitol, D-mannose, D-galactose, soluble starch, xylose, L-arabinose, inositol, dextrin and glycerin were identified as the suitable carbon sources for growth and sporulation. Significant correlation was observed between the mean colony diameters and the numbers of conidia produced among the three isolates. Nitrogen sources had significant effects on the numbers of conidia produced, not on the colony diameters. L-cysteine and L-phenylalanine were the most suitable nitrogen sources for growth and sporulation of the three isolates. L-proline and potassium nitrate were identified as the suitable nitrogen sources for growth and sporulation of the three isolates. The isolate CLER09 had the following nutritional characteristics: maltose, α-lactose, D-mannose and dextrin as the carbon sources were suitable for growth and sporulation followed by L-histidine; sucrose as a carbon source was unsuitable for growth and sporulation; significantly positive correlation was observed between the colony diameters and the numbers of conidia produced with reference to the carbon sources; no significantly positive correlation was observed between the colony diameters and the numbers of conidia produced with reference to the nitrogen sources. The isolate D087 had the following nutritional characteristics: D-mannose as a carbon source was unsuitable for growth and sporulation; asparagines, thymine, glutamic acid and vitamin B1 had the secondary suitability as the carbon sources for growth and sporulation; significantly positive correlation was observed between the colony diameters and the numbers of conidia produced with reference to the carbon sources; no significantly positive correlation was observed between the colony diameters and the numbers of conidia produced with reference to the nitrogen sources. Isolate JL05 had the following nutritional characteristics: glucose and trehalose were the most suitable carbon sources for growth and sporulation followed by mannitol; no significantly positive correlation was observed between the colony diameters and the numbers of conidia produced with reference to both carbon and nitrogen sources. In conclusion, general and individual carbon and nitrogen requirements existed among isolates of E. rostratum for growth and sporulation.

Radish (Raphanus sativus), an important original Raphanus vegetable, is widely distributed in China. It exhibits high nutritional value because of rich in vitamins, phenolic compounds, and dietary fiber. Many bioactive compounds show the important biological functions, such as antioxidant and anticarcinogenic effects. Therefore, the colored vegetables, as a rich source of various bioactive compounds, have achieved more and more attentions. Radish can be divided into white radish, green radish and red radish according to skin color. Green and red radishs, which were widely grown in Sichuan Province, could be consumed not only in fresh but also as main raw materials of Sichuan pickles, and the edible parts include the petiole, root peel and root flesh. Although the nutrient qualities in root flesh of radish have been investigated, limited information is available about the bioactive compounds and antioxidant capacities among different edible parts in green radish and red radish. We aimed to investigate the variation of the contents of vitamin C, carotenoids, anthocyanins, proanthocyanidins, chlorophylls, flavonoids, and total phenolics, as well as antioxidant capacities among different edible parts in green radish and red radish. Our systematic study on radish will provide the foundation to guide human consumption. In September 2013, the seeds of green radish (cv. Lutouqing) and red radish (cv. Hongyou) were sown at Yaan City, Sichuan Province. Petioles and roots were harvested together in early morning, put on ice and transported to laboratory within 10 min. For each sampling, five plants were collected as a replicate, and four independent replicates were taken for analysis. The samples were cleaned and separated according to different edible parts, and then the contents of bioactive compounds and antioxidant capacities were determined. The correlations were analyzed by SPSS 18.0 software. The results showed that both contents of bioactive compounds and antioxidant capacities exhibited remarkable differences among different edible parts in green radish and red radish. In general, the lower contents were found in flesh. The contents of proanthocyanidins, carotenoids and chlorophylls in green radish were notably higher than those in red radish. On the contrary, the contents of vitamin C, anthocyanins and total phenolics in red radish were higher than those in green radish. Moreover, significant positive correlations were found between ferric reducing antioxidant power (FRAP) and all bioactive compounds, respectively, whereas 2,2’-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) was just significantly correlated with carotenoids and chlorophylls. The results suggested that FRAP is suitable for the analyses of antioxidant capacity in radish. In conclusion, the contents of bioactive compounds and antioxidant capacities show significant differences among edible parts and species of radish. The edible parts of green radish and red radish contain high nutritional value, and are as good candidate for human daily consumption.

Shiga toxin-producing Escherichia coli O157:H7, one of the most emergent foodborne pathogens, can cause illnesses ranging from diarrhea to hemorrhagic colitis and hemolytic-uremic syndrome. Escherichia coli O157:H7 is spread into the environment via fecal shedding or field application of farm effluent. The produce can be contaminated by E. coli O157:H7 through soil, feces, irrigation water, manure application, insects, or postharvest washing. Fresh produces, especially leafy greens that be consumed raw, are increasingly being recognized as the foremost transmitting vehicles. Many studies have shown that E. coli O157:H7 can internalize within a variety of tissue types. Although the internalized E. coli O157:H7 makes no difference to the normal growth of plants, it brings risks when people take in the unpasteurized fresh food. In this review, sources of contamination, main routes of internalization, interactions between internalized E. coli O157:H7 and the plant host as well as other microbes were stated. The internalization of E. coli O157:H7 in fresh produce has been found to be associated with many routes including stomata, lenticels, sites of root emergence and sites of biological or physical damage. Because stomata are generally found in greater densities on the underside of leaves, greater internalization of E. coli O157:H7 on leaves would be likely on the abaxial side than on the adaxial side. Root uptake of E. coli O157:H7 and subsequent internalization has also been widely reported. Damaged leaves release more nutrients onto the leaf surface, which allow E. coli O157:H7 to grow and induce more E. coli O157:H7 to get into the leaves. Various factors including growth substrate, inoculums level, and plant species and cultivar, have shown to affect the level of internalization. Although there is no obvious change on the appearance of the plant, complicated interactions between internalized E. coli O157:H7 and the plant hosts have been discovered. Plant hosts have some pattern recognition receptors (PRRs) to recognize pathogen associated molecular patterns (PAMPs), and further activate plant immune response to limit the growth and spread of the pathogen. PAMPs contain flagellin, peptidoglycan, lipopolysaccharide, and other components which derived from pathogens. Studies have showed that elimination of these PAMPs leads to better growth of E. coli O157:H7 in the plant. Furthermore, phytopathogen can grow in the plant through secreting effector proteins to disturb the recognition of PAMPs by PRRs. Whether human pathogen currently carries the effector proteins is yet to be determined. Further research is needed to explain the mechanism of E. coli O157:H7 invasion and growth in the plant hosts. In addition, interactions between E. coli O157:H7 and the epiphytic microbes would affect the internalization of E. coli O157:H7. The metabolic products of the epiphytic microbes and the competition of nutrients between E. coli O157:H7 and the epiphytic microbes could limit the growth of E. coli O157:H7. On the other hand, some epiphytic microbes could produce available carbon sources to help E. coli O157:H7 grow and get into the plant hosts. In short, better understanding of the internalization of E. coli O157:H7 in plants and risks will be helpful in reducing the pathogenic infection to human. Further researches remain to be done in revealing the molecular and genetic details of the mechanisms that are involved to control the contamination of fresh produce by human pathogenic bacteria.

Many countries such as USA, Canada, Denmark and Swiss, and their states or provinces, have carried out systematic researches on the remediation criteria of contaminated soils, and their relevant remediation standards for contaminated soils have also been enacted nationwide or statewide. Especially for USA, it has so many states that there are a series of methodologies provided for references, just as “soil cleanup levels” in Alaska, “soil remediation standards” in Arizona, “soil cleanup target levels” in Florida, “soil remediation goals” in North Carolina, and so do many other countries such as “Canada soil quality guidelines” and “Canadawide standards for petroleum hydrocarbons”, “cutoff criteria” in Denmark, “action values” in Germany, “target cleanup levels” in Italy, “soil remediation intervention values” in Netherlands, and “cleanup values” in Swiss. Generally speaking, the protection of human health is the key point in most of the remediation standards among various countries or states. Meanwhile, ecosystem safety is also included as the protected objects independently, and sometimes groundwater protection is also taken into consideration directly or indirectly. At the same time, the past, current or future land uses are often discriminated in the remediation criteria for most of the countries or states. Nevertheless, the remediation standard for contaminated soils is still a gap in China and thus it is of great urgency to carry out the systematic and comprehensive research on the remediation criteria to meet the need for contaminated soil remediation under various land uses. In general, the research about “derivation methods of remediation criteria/standards for contaminated soils under different land uses and analysis of their standard values” is of great significance and necessity. Firstly, the connotation and function of remediation criteria and standards for contaminated soils are explained in brief combined with the screening values. Noticeably, the preliminary remediation goal is that remediation standards of contaminated soils intend for the protection of human health, was firstly developed at the national level in USA, while its guidance was commonly used to derive some screening levels under the similar supposed contexts and thus the screening values were used as the remediation goals for these soils. However, in 1996, the Soil Screening Guidance (SSG) was enacted by US EPA for the derivation of screening values specially, and stated that the function of soil screening levels is to screen out a contaminated site and its potential pollutants. And in most European countries, the screening values are regarded as soilenvironmental quality standards rather than remediation standards of contaminated soils. In fact, remediation standards of contaminated soils should be the guidance for the nationwide or statewide remediation projects and the protection of plow lands. Land uses should be considered in derivation and development of remediation standards for contaminated soils, and the reference methods are suggested for the development of remediation standards for contaminated soils under various land uses. Then, it is followed by deriving and enacting methods of remediation criteria for contaminated soils under different land uses and the analysis of their standard values. We set forth the variations of the methods and the standard values under various land uses as the result of various remedial requirements and exposure scenarios from three aspects, that is, human health, ecosystem safety and groundwater protection. Generally speaking, exposure scenarios are different in various land uses, and there are some discrimination on exposure population, exposure pathways, and exposure parameters based on human health, while the differences are mainly reflected on receptors, and toxic indicators for ecobased remediation criteria. As for groundwater protection based remediation criteria, water quality standards are often used for the back calculation of soil remediation criteria by the soilwater partition equation, and they are somewhat different in terms of the function of groundwater under various land uses. Otherwise, remediation standards for Cd and benzene contaminated soils in some countries and states are compared qualitatively. In conclusion, many countries have enacted the nationwide or statewide remediation standards for contaminated soils, and are expressed by different denominations. In general, four types of land uses (agricultural, residential, commercial/industrial, groundwaterprotection land uses) are considered in development of remediation standards, and there are some discrimination on the methods and the standard values under various land uses.

Litter not only can avoid plants being suffered from splash erosion, wind erosion and other physical protection of rain, but also can accelerate the accumulation of soil moisture, nutrients, and improve soil fertility. In the last decade, The National Projects of Ecological Engineering such as Returning Cropland to Grass and Enclosure Steppe, have been performed, but effects of litter input on soil physical and chemical properties under the fenced condition in desert steppe remain poorly understood. We created field decomposition experiment and laboratory experiment based on four typical plant communities under a fenced condition, which were Agropyron crisatum community, Glycyrrhiza uralensis community, Leymus secalinus community and Artemisia desertorum community, and analyzed the basic characteristics of four typical plant communities, litter accumulation and decomposition, and soil moisture and nutrients, respectively. The results showed that the litter accumulation under the fenced condition was significantly higher than that of the no fenced condition, and the litter accumulation increased soil water holding capacity, while the litter decomposition had weak effect on soil bulk density, total porosity and water holding capacity in the short term. Although soil pH value decreased with the litter accumulation, but the variation was small. Litter input had positive effect on the soil total nitrogen in the short-term, but the effect was weak, and the soil total nitrogen and organic carbon increased with increasing litter accumulation. These results supported that the litter accumulation and decomposition in the desert steppe could effectively improve the soil water movement and spatial distribution, and transport more organic and nutrient elements into the soil, thus change the physical and chemical properties of soil. The finding suggests that litter has positive effect on vegetation and soil restoration of the desert steppe, which plays more important role in maintaining ecosystem stability in the arid sand areas.

Activated carbons (AC) are effective adsorbents for removal of a wide variety of organic pollutants in aqueous media or gaseous environments. Their high adsorption capacity largely depends on the well-developed internal pore structure, surface area and special surface reactivity. However, general AC have not selective adsorption ability, which are often required in many practical uses such as reducing certain harmful chemicals from mainstream cigarette smoke. Therefore, modification to endow AC with selective adsorptivity is important and attractive. Based on the findings of nonsolvent induced phase separation from a cellulose acetate (CA) ternary solution in a mixed solvent of acetone and water, we successfully covered a CA porous film on the surface of AC particles. Scanning electron microscopy (SEM) was used to observe the surface morphology of the CA films, and Brunner-Emmett-Teller (BET) measurement was used to characterize the surface area of the modified AC particles. The experimental results showed that the coverage rate of the porous CA film with an average pore size about 426 nm on the AC particles was over 80%, and the surface area of the modified AC particles (672 m2/g) was lower than that of the original AC (834 m2/g) used. To investigate the selective adsorption property, pyrene, cinnamonitrile, benzene, phenol, benzoic acid, thymol and vanillin, which are the typical chemicals in the mainstream cigarette smoke, were selected as the model compounds in the simulating adsorption tests. For the gas adsorption experiments, the chemicals (each 0.1 g) were dissolved in chloroform (1.5 mL). Sixty millilitres of the mixed solution was dropped to a ball of cotton fiber (0.1 g), and put in a closed container after the chloroform had been volatilized. The control sample of the original AC and the modified one (each 0.2 g) were put in the closed container with the same distance (10 cm) to the cotton ball for 24 hours. For the aerosol adsorption experiments, the chemicals (each 0.1 g) were dissolved in acetone (15 mL). One point five millilitres of the mixed solution was uniformly sprayed to the tobacco (0.55 g) taken from a cigarette product, and burned in the closed container. Similar AC adsorption tests were carried out for 12 hours. These two tests were all repeated five times and the obtained samples were put together respectively. All adsorption quantities of the AC samples were analyzed by high performance liquid chromatography (HPLC) method. The adsorption results, both in gas and aerosol conditions, indicated that the modified AC particles could absorb more harmful substances, i.e., pyrene, cinnamonitrile, phenol, but much fewer aroma components, i.e., benzoic acid, thymol, than the original AC. Contrasted with the original AC in gas adsorption test, the adsorption capacity of the modified AC increased about 17% for phenol but reduced about 60% for benzoic acid. In aerosol condition, it increased about 78% for phenol but decreased 88% for thymol. In conclusion, this study provides a novel surface modification method for AC by covering CA porous film on the surface of AC following the nonsolvent induced phase separation mechanism. It demonstrates that the modified AC have improved the selective adsorption property. One of the potential applications of the modified AC particles is the use as a cigarette filter additive to remove harmful chemicals with little loss on the flavor of the cigarette products.