Abstract:Abstract: Drug-resistance mutation of microorganisms reflects structure and function changes of the ribosome and RNA polymerase. These changes can have significant effects on secondary metabolism in the mutant strain. Thus, ribosome engineering is an effective approach to develop mutant strains that overproduce secondary metabolites (i.e. antibiotics) by screening various drug-resistance mutations. We introduced the concept and the mechanisms of the ribosome engineering. The efficacy of the strain improvement was highlighted in Streptomyces spp. by introducing combinatory drug-resistances. The applications of the method in the strain-breeding of various bacteria were also summarized.

Abstract:Abstract: Insertion sequence common region (ISCR) elements are insertion sequences that have similarities to the IS91 family in both structure and function. ISCR elements differ from the insertion sequences by that they lack terminal inverted repeats (IRs), do not generate directly repeated sequence on insertion and are thought to be transposed by a mechanism termed rolling-circle (RC) transposition. ISCR elements, as a novel gene-capturing system, can mobilize any piece of adjacent DNA sequences. This powerful gene mobilization mechanism provides antibiotic resistance genes with a highly mobile genetic vehicle to transfer between different species of bacteria. Nineteen members of the ISCR family have been discovered until now in many Gram-negative pathogens. The majority of these elements are found to be closely associated with antimicrobial resistance genes that are not necessary components of the host genome, suggesting that ISCR elements may be responsible for the rapid transmission of bacterial multi-drug resistance. This review described some important aspects of ISCR elements, including their structure characteristics, classification, mobilization mechanism, origins and evolutions.

Abstract:Abstract: [Objective] In order to study the diversity of archaea and ammonia-oxidizing archaea (AOA) of the alp prairie soil in Mila Mountain of Tibet. [Methods] Total microbial DNA was directly extracted from the alp prairie of Mila Mountain. The clone library of 16S rRNA genes and amoA genes were amplified by PCR with universal primer sets. Through 16S rRNA gene and amoA gene cloning library technology to analysis the composition of Archaea and AOA community structure in the alp prairie soil of Mila Mountain. [Results] Phylogenetic analysis revealed archaea in the soil of Mila Mountain including the Crenarchaeota (71.7%) and unclassified_Archaea (28.3%) phyla. All the Crenarchaeota belong to the Thermoprotei. Phylogenetic analysis revealed AOA in the alp prairie soil of Mila Mountain belonged to the kingdom Crenarchaeota. Through DOTUR software analysis, Archaea and AOA species composition from Mila Mountain included 64 OTUs and 75 OTUs. [Conclusion] These findings show prolific archaeal diversity in the alp prairie soil of Mila Mountain, where they may be actively involved in nitrification. In addition, there have some unclassified Archaea in the clone library, it means that they may represent some novel archaeal groups.and what? Meaningless!

Abstract:Abstract: [Objective] To identify and characterize the strain 08Hl01032 was isolated from air condition systems in the routine investigations of Legionella in Guangzhou, China, in 2008. [Methods] We adopted several phenotypic and genotypical methods, such as the growth status on various media, morphological, physical and biochemical characteristics, animal test, antibiotic susceptivities, PCR identification, sequence analysis of 16S RNA and RNA polymerase β-subunit (ropB) gene etc, to determinate the phylogenetic position and outline the basic biological characteristics. [Results] Strain 08Hl01032 was Gram-negative with polymorphic short rods or coccobacillus; with no flagella; devoid of spores; well growth on buffered charcoal yeast extraction (BCYE) agar and BCYE supplemented with glycine (3 g/L), polymyxin B sulfate (80,000 iu/L), vancomycin (1 mg/L) and cycloheximide (80 mg/L) (GVPC medium) within 2 days, but delayed growth on ordinary sheep blood agar untill 5~7 days; catalase positive; oxidase negative; no reduction of nitrate; no hydrolysis of urea; delayed fermention of glucose to produce acid; which was primarily considered as Legeionella. It was lastly identified to the genus Fransicella, characterized by a variety of biochemical and molecular phylogenetic tests, which shared the highest similarities to F. Philomiragia with 95.3 % to 16S rRNA gene of 1377 oligo nucleotides and 87.3 % to ropB gene of 367 oligo nucleotides (GenBank accession number: FJ591095, FJ939309). Growth were observed after a treatment for 10 minutes with the KCl-HCl buffer of pH 2.2, 20oC, and at 25℃, 37 oC (optimum 25~28 oC ), but not at 42 oC. The cells had capsule-like construction by transmission electron microscopy, however no virulence found to mice. [Conculsions] Strain 08Hl01032 was a potential new species of the genus Fransicella with a typical characteristic of L-cysteine growth stimulating activity, distinguishingly to Legionella with L-cysteine growth dependent activity.

Abstract:Abstract: [Objective] To investigate the reliability of single-strand conformation polymorphism (SSCP) analysis of 26S rDNA D1/D2 domain for rapid identification of clinical yeast species and to examine the distribution of the yeast species in clinical strains from Beijing. [Methods] Type and authentic strains of five common pathogenic yeast species were used as references. Approximately 260 yeast strains with diversified clinical origins were collected from four hospitals located in Beijing. The 26S rDNA D1/D2 domain of each strain was amplified by PCR and subjected to SSCP or sequence analysis. [Results] SSCP analysis showed that the Candida strains with slight sequence differences in the D1/D2 domain could be effectively detected. The common pathogenic Candida species, including C. albicans, C. parapsilosis, C. tropicalis, C. glabrata and C. krusei, were clearly distinguished from each other by their SSCP patterns of PCR amplified D1/D2 domain products. Twenty species belonging to 10 genera were identified from the approximately 260 clinical yeast strains based on SSCP pattern comparison for the common species and D1/D2 sequence analysis for the uncommon species. The dominant species and their frequencies were: C. albicans (57.7%), C. parapsilosis (10.0%), C. tropicalis (9.2%), C. glabrata (6.7%) and C. krusei (5.8%). [Conclusion] The results indicated that PCR-SSCP analysis of D1/D2 is a powerful approach for rapid species identification of clinical yeast strains. The most common clinical yeast species was C. albicans in Beijing but the increasing trend of non-albicans Candida species was observed.

Abstract:Abstract: [Objective] The hrp(hypersensitive response on nonhost plants and pathogenicity in host plants) gene cluster, which conforms Xanthomonas oryzae pv. oryzicola, the causal agent of bacterial leaf streak in rice, to the ability to elicit a hypersensitive response (HR) in nonhost tobacco and pathogenicity in host rice, is thought to be regulated by the hrpG and hrpX genes. However, it is unclear whether the hrpG and hrpX genes regulate all the hrp gene expression of the cluster coordinately or not. [Methods] We constructed a mutant with both hrpG and hrpX genes knocked out. [Results] which, as the same as the single mutant at the hrpG or hrpX gene, lost the ability to trigger HR in tobacco and pathogenicity in rice, respectively. Correspondingly, the hrpG and hrpX genes together could restore such the ability to the double mutant at the hrpG and hrpX loci. After grew in rice suspension cells, hrp-inducing medium XOM3 and nutrient-rich medium NB for 16 hours, respectively, reverse transcriptional polymerase chain reaction (RT-PCR) revealed that: the expression of hrp genes in NB medium was lower that that in rice cells and XOM3 medium; in whatever growth media, the hrcC, hrcT, hrpE and hpa3 genes expressed, while the hpa1, hpa2, hpaB, hrcJ, and hrpG genes did not in the hrpG mutant; the hpa2, hrcC, hpa3, hrpE and hrpG genes expressed, while the hpa1, hrcT, hpaB and hrcJ genes did not in the hrpX mutant; the hrcC, hrpE and hpa3 genes expressed, but the hpa1, hpa2, hpaB, hrcT, hrcJ and hrpG genes did not in the hrpG and hrpX double mutant. [Conclusion] This indicated that the expression of the hrcC, hrpE and hpa3 genes was not regulated by the hrpG and/or hrpX genes, but the expression of the hrcT gene was negatively controlled by the hrpG gene. Thus, we postulated that the expression of key type-III secretion (T3S) apparatus components was controlled by an unknown signaling pathway, which may facilitate our further understanding on the formation of the T3S machine.

Abstract:Abstract: [Objective] To construct an engineering strain of higher desulfurization activity with Vitreoscilla hemoglobin gene (vgb) for desulfurization of diesel. [Methods] We constructed the vgb expressing plasmid, pPR-Pdsz-vgb and transformed by electroporation to Pseudomonas delafieldii R-8, then obtained a genetic engineering strain R-8-2. [Results] The results of CO-difference spectrum analysis indicated that R-8-2 expressed Vitreoscilla hemoglobin (VHb) having biological activity expressed in strain R-8-2. Compared with the wild-type R-8, the density of strain R-8-2 increased by 20%, and its desulfurization activity is also higher in the lower deliquescence oxygen environment. In the end, about 69.9% of total sulfur in diesel oil was removed by strain R-8-2, whereas only 57.2% of sulfur was removed by strain R-8. [Conclusion] The activity of strain R-8-2 was enhanced and furthermore, the work is helpful for further development in biodesulfurization.

Abstract:Abstract: [Objective] We attempted to gain insights into the phenotypic and genetic characteristics of a naturally atypical Listeria monocytogenes strain S10 lacking inlAB. [Methods] The isolate S10, together with 7 L. monocytogenes strains representing different serovars, were studied by biochemical profiling, adhesion assay in HeLa cells, virulence to mice, detection of virulence-associated genes detection and genetic lineage analyses. [Results] The S10 isolate belonged to lineage I and serovar 1/2b, with carbohydrate fermentation and hemolytic characteristics typical of L. monocytogenes. However, this strain had reduced adhesion to HeLa cells and decreased pathogenicity to mice. It lacked the gene locus inlAB and their adjacent genes lmo0431, lmo0432, lmo0436 and lmo0437, but contained an almost whole set of infection-associated genes. S10 fell into the lineage I cluster and form a sister branch with 4b strain. [Conclusion] The isolate S10 represents the first report of atypical L. monocytogenes lacking inlAB. As it lacked the inlAB locus from an otherwise typical lineage I genetic background, inlAB was probably lost from the genome via independent deletion event.

Abstract:Abstract: [Objective] pSCM201 is the first unidirectional theta replication plasmid experimentally identified in the domain of archaea. For gene expression and function analysis of specific genes in model strain Haloarcula hispanica, a novel shuttle expression vector based on pSCM201 was developed. [Methods] By combining the minimal replicon of pSCM201, the pUC19 replicon of Escherichia coli, and two antibiotic genes, a new shuttle vector between haloarchaea and E. coli was established. Furthermore, the hsp5 core promoter, multiple clone sites and a C-terminal His?Tag sequence were added to construct the expression vector pSCM307. With the help of reporter gene bgaH, the replication ability and gene expression of pSCM307 were tested in H. hispanica AS2049 by PCR identification and β-galactosidase activity assay. [Results] pSCM307 could stably self-replicate in AS2049, and bgaH was successfully expressed under the control of hsp5 promoter. [Conclusions] A user-friendly expression vector was successfully constructed in haloarchaea.

Abstract:Abstract:［Objective］The reverse genetics technology is an important way to develop genetically engineered attenuated living human respiratory syncytial virus (RSV) vaccine candidates. As the pilot experiment, it is necessary to prepare RSV minireplicon and investigate its biological activity.［Methods］After the gene start and gene end (GSGE) fragment containing the sequence of leader (Le), gene start (GS), multiple cloning sites (MCS), gene end (GE) and trailer (Tr) was synthesized and positioned under the control of T7 RNA promoter, we cloned this fragment further into px8δT vector. Then, the enhanced green fluorescent protein (EGFP) was cloned into the above px8δT vector, and RSV minireplicon plasmids px8δT/GSGE1/EGFP and px8δT/GSGE2/EGFP were finally obtained. Meanwhile, two ORFs of nucleocapsid proteins of large protein (L) and transcription elongation/antitermination factor (M2-1) were cloned and constructed to produce pcDNA3.1/L and pcDNA3.1/M2-1. At the end,we co-transfected a RSV minireplicon plasmid and four nucleocapsid protein plasmids into BSR T7/5 cell lines expressing T7 RNA polymerase by lipofectamine 2000, and analyed the expression of EGFP by inverted fluorescent microscopy and fluorescence activated cell sortor (FACS), respectively.［Results］ The px8δT/GSGE1/EGFP, px8δT/GSGE2/EGFP, pcDNA3.1/L and pcDNA3.1/M2-1 were successfully constructed. After co-transfecting, EGFP can be observed in the transfected BSR T7/5 cells under fluorescent microscopy and by FACS. ［Conclusion］The constructed RSV minireplicon is able to replicate and transcript, which provides a solid foundation for further RSV vaccine study by RSV reverse genetics.

Abstract:Abstract: [Objective] The ovine rotavirus strain NT isolated from diarrhea lamb in China was considered as a promising vaccine strain. Based on the VP1 gene was one of the important structural proteins of rotavirus, we studied on the evolutional characteristics of VP1. [Methods] According to the published conservative sequences of VP1 genes, we designed a pair of specific primers for cloning and sequencing of VP1 gene. [Results] Sequencing result showed that the VP1 gene was 3,302 bp in length and the deduced protein was 1,088 aa. Comparison of amino acid sequences revealed that the ORV-NT shared 77.3% - 98.4% similarities with other group A rotaviruses. Furthermore, sequence alignment analysis manifested that amino acid variations mainly occurred in the non-functional regions of VP1 protein. Phylogenetic analysis of VP1 protein showed that the OVR-NT was grouped in the bovine rotavirus clusters, indicating a closer relationship between them. Evolutionary distance of nucleotide sequence and amino acid sequence among VP1 genes of different rotaviruses were calculated, respectively. Analysis of synonymous mutation rate and Non-synonymous mutation rate demonstrated that synonymous substitution was the major pattern of variation in the process of evolution. [Conclusion] This was the first report on sequencing and evolutionary distance analysis of VP1 gene of ORV-NT.

Abstract:Abstract: [Objective] Ergosterol is a fungal metabolite with economic importance. For ergosterol biosynthesis, to identify the bottleneck enzymes in the metabolic pathway is of crucial importance. [Methods] Sterol C-8 isomerase encoding gene ERG2 was cloned from Saccharomyces cerevisiae by PCR. To evaluate the effect of ERG2 overexpression on the sterol content in the yeast, the expression plasmid pPERG2 was constructed and transformed into S. cerevisiae strain YS58 to generate recombinant strain YS58(pPERG2). In addition, the regulation role of sterol C-24 methyltransferase, encoded by ERG6, in ergosterol biosynthesis was further verified by analysis of sterol components and levels in yeast strains overexpressing ERG6, ERG2 respectively, or overexpressing ERG6 and ERG2 simultaneously. [Results] Ergosterol content and all sterol intermediates increased largely by overexpressing ERG6 in S.cerevisiae. Although the overexpression of sterol C-8 isomerase encoded by ERG2 alone had negative effect on ergosterol biosynthesis, overexpression of ERG6 and ERG2 simultaneously led to an increased ergosterol level, which was 1.41-fold of that in empty vector strain, 1.92-fold of that in ERG2 only overexpressing strain and 1.12-fold of that in ERG6 only overexpressing strain. [Conclusion] These results demonstrated that sterol C-24 methyltransferase is an important bottleneck enzyme for ergosterol biosynthesis in S. cerevisiae.

Abstract:Abstract: Serine/threonine protein kinase YPK1, a homologue of mammalian protein kinase serum and glucocorticoid-inducible kinase (SGK), plays important physiological roles in Saccharomyces cerevisiae. It involves in cell wall maintenance, actin cytoskeleton dynamics, endocytosis, translation during nitrogen starvation and nutrient sensing. [Objective] In order to further explore the cellular function of YPK1 and the its transduction pathway. [Methods] We overexpressed YPK1 in wild type and tor1 mutant cells and monitored the cell growth responding to salt stress. [Results] We found that YPK1 overexpression resulted salt stress hypersensitivity in wild type cells and this hypersensitivity was abolished by tor1 mutant. [Conclusion] Our results indicate that YPK1 may interact with target of rapamycin (TOR1) to regulate the salt stress response.

Abstract:Abstract: [Objective] To screen and breed high lysine-producing strains by genome shuffling. [Methods] Corynebacterium pekinense 1 was used as the starting strain in this study. High lysine-producing strains were screened by genome shuffling. [Results] Five hereditarily stable strains with high lysine production were obtained by four cycles of genome shuffling. A high lysine producing strain, F4-36, was obtained, which produced 16.95 g/dL lysine, 37.1% higher than that of the starting strain. [Conclusion] Genome shuffling can be an efficient tool to screen and breed high lysine production strains.

Abstract:Abstract: [Objective] To screen cellular protein interacted with influenza A M2 protein(A/M2). [Methods] we cloned A/M2 gene fragment into pCAGGS-CFlag vector, and the resulting plasmid was transfected into human embryonic kidney (HEK) 293T cells.The recombinant Flag fusion protein,A/M2-Flag was absorbed specificly by Anti-Flag Monoclonal Antibody M2-Conjugated Agarose beads, we loaded the beads on 12% SDS-PAGE after we washed it with lysis buffer. Silver staining of the gel revealed that several proteins were co-purified with A/M2.To identify the proteins,we excised the protein bands and analysed them by mass spectroscopic sequencing. [Results] We got two kinds of proteins, ataxin 10 and eukaryotic initiation factors(eIFs). [Conclusion] Interaction between Ataxin 10 and A/M2 would explain why inflenza virus infection or influenza vaccine innoculation causes acute cerebellar ataxia. A/M2 interacting with eIFs would imply that A/M2 is involved in the regulation of influenza virus protein synthesis.

Abstract:Abstract: [Objective] We cloned, expressed and characterized a novel lipase gene lipB from Aspergillus niger F044, to facilitate the large scale production and application of that enzyme. [Method] We cloned lipB gene and the cDNA sequence by PCR and RT-PCR, and then cloned the open reading frame of lipB into pET28a vector and expressed by isopropyl β-D-1-thiogalactopyranoside (IPTG) induction. After Ni-agarose purification, the characteristics were determined and the conformation change was checked by circular dichroism methods. [Results] The novel lipase genes cDNA of lipB were cloned from Aspergillus niger F044 (GenBank: FJ536287, FJ536288) and expressed in Escherichia coli. The molecular weight of LipB was about 43 kDa. The optimal substrate of this enzyme is 4-nitrophenyl octanoate (pNPC-C8) with Km=5.98 mmol/L. The optimal temperature and pH was 50oC and pH 6.0. The enzyme was stable below 40 oC. After incubated at 60 oC for 1 h, only 18.8% activity remained. After treated by 2 mmol/L Ca2+ for 1 h, the activity improved 2.6-fold. [Conclusion] Enzymatic characteristics of LipB determined showed this enzyme might have potential in industrial applications.

Abstract:Abstract: Temperature is important factor affecting the bacterial diversity. [Objective] In order to disclose the effect of temperature on the diversity of microorganisms, [Methods] The diversity of microorganisms associated with the sponge Pachychilina sp. at 16℃ and 30℃ of the seawater in the Gulf of Zhanjiang was examined by a restriction fragment length analysis termed ARDRA (amplified rDNA restriction analysis) and 16S rRNA-encoding DNA (rDNA) sequence analysis The computer-aided clustering was performed after separate restriction analysis with enzymes HaeⅢ. [Results] By this method, 100 cloned 16S rDNA fragments were clustered into a total of 34 different groups at 16℃ and 32 different groups at 30℃. HaeⅢ ARDRA patterns showed different among eubacteria living at different temperature degree, whereas the whole communities of eubacteria were not changed distinctly. Screening 60 clones by sequence analysis suggested vast majority of eubacteria related to α, γ, δ subclasses of the class Proteobacteria, some related to sulfur bacteria, desulfobacter, and hydrocarbon utilizing bacteria, minority belonging to actinomyceten at 16℃ and 30℃. α subclass of the class Proteobacteria were the predominant bacteria at 30℃, and γ-Proteobacteria were predominant bacteria at 16℃, additionally sulfur bacteria and desulfobacter were mainly attributed to chilly-enduring bacteria. Sequence analysis of clones with an identical ARDRA pattern confirmed that members of an ARDRA group were closely related to each other.

Abstract:Abstract [Objective] To study the effects of Helicobacter pylori jhp947 gene on the pathogenesis of epithelial cells and gene express pattern by animal studies . [Methods] Twenty-seven special pathogen free (SPF) C57BL/6 mice were divided equally into 3 groups, and challenged with Helicobacter pylori J99, Helicobacter pylori△J99-947 and phosphate buffer (PBS) respectively, at a dose of 109 colony formine unit (CFU) at 0, 2, and 4 days. Mice were sacrificed 4 weeks after the last challenge, and went through rapid urease test, culture of Hp, histological examination ,immunofluorescent histochemistry and semiquantitative reverse transcription PCR (RT-PCR) of gastric mucosa. [Results] The result of rapid urease test and culture of Hp indicated that the positive rates in J99 and △J99-947 group were both 100% while 0% in PBS group. The result of histology examination indicated that garstirc mucosa is all normal in PBS group; in J99 group, 33.3% (3/9） had slightly anabrosis, 66.7% (6/9) had seriously anabrosis; in △J99-947 group, 22.2% (2/9) is normal, 77.8% (7/9) had slightly anabrosis. The degree of anabrosis seems to be more severe in J99 than in △J99-947. The result of immunofluorescent histochemistry and semiquantitative RT-PCR of gastric mucosa indicated that the expression level of ets homologous factor, N-myc downstream regulated gene 1, methylthioadenosine phosphorylase is significantly lower in J99 than in △J99-947 group (P<0.05). [Conclusion] The degree of anabrosis seems to be more severe in Hp with jhp947 gene than in Hp without jhp947 gene. In vivo, jhp947 may induce tumorigenesis by inhibiting anti-oncogenes（N-myc downstream regulated gene 1 and methylthioadenosine phosphorylase）.

Abstract:Abstract:[Objective] The study was aimed to prepare an oral vaccine by constructing recombinant Lactobacillus casei expressing alpha-toxin gene of Clostridium perfringens, for preventing poisoning by Clostridium perfringens. [Methods] The constructed cell-surface expression plasmid pPG1-ɑ/L.393 and secretion expression plasmid pPG2-ɑ/L.393, both with alpha-toxin gene, were electroporated into L.casei 393, generating recombinant bacteria pPG1-ɑ/L.casei393 and pPG2-ɑ/L.casei393. The recombinant strains were induced by 1% lactose in De Man, Rogosa and Sharp (MRS) broth, and the target protein was detected by 12% sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE), Western blot and indirect immunofluorescence assay. BALB/C mouse were used as animal model immunized with recombinant strains by intragastric administration, and the immune efficacy was analyzed. Specific anti- alpha-toxin protein sIgA was detected by indirect enzyme linked immunosorbent assay (ELISA) in the feces, vaginal lavage, eye washing of mice after intragastric administration, and Specific IgG was detected by indirect ELISA in the serum of immunized mice. The resistance of immunized mice to alpha-toxin and the neutralization ability of antibodies to alpha-toxin were also tested. [Results] Mice immunized with pPG1-ɑ/L.casei393 and pPG2-ɑ/L.casei393 could produce remarkable anti-alpha-toxin antibodies, sIgA and circulating antibody IgG had completely neutralization ability against alpha-toxin. The test of alpha-toxin challenge in mice showed that the immunized mice could resist three times’ Minimum Lethal Dose(MLD). [Conclusion] All the results indicated that mice inmmunized by the recombinant Lactobacillus casei expressing alpha-toxin gene of Clostridium perfringens could elicit regional and systematic immunity response and neutralization ability.

Abstract:Abstract: [Objective] The effects of exogenous Zn addition on cell protective enzyme activities in the fruit bodies of Lentinus giganteus were studied. [Methods] ZnSO4 was used as exogenous Zn and added into culture medium. The final Zn concentrations in culture media were 0, 10, 20, 30, 40, 50 mg/kg respectively. The activities of superoxide dismutase (SOD), peroxidase (POD), polyphenol oxidase (PPO), malondialchehyche (MDA) content and soluble protein content in the fruit bodies were analyzed by spectrophotometry; catalase (CAT) was determined by potassium permanganate titration. [Results] The content of soluble protein and SOD, POD and CAT activities in the fruit bodies of L. giganteus were significantly increased (P<0.01), but PPO activity (P<0.01) and MDA content (P<0.05) was significantly decreased in the treatment of 30 mg/kg Zn concentration. The content of soluble protein and SOD, POD and CAT activities showed a decreasing trend with the increase of Zn concentration, but MDA content was significantly increased (P<0.01 and P<0.05 ). [Conclusion] High Zn concentration caused the increase of MDA contents and the decrease of SOD, POD and CAT activities in the fruit body of L.giganteus. It will destroy the protective enzyme system, cause the accumulation of free radicals and thus intensify membrane lipid peroxidation. Appropriate Zn concentration improved the protective enzyme activities, and lightened the harm of membrane from lipid peroxidation.