Most downloaded articles

1 Microbial diversity of a community for ensiling rice straw at low temperature and fermentation dynamics

Hongyan Yang , Xufeng Yuan , Xiaoping Liu , Xiaofen Wang , Zongjun Cui

2011, 51(9):1248-1255.

[Abstract](1299) [HTML](0) [PDF 932.00 K](22698)

Abstract:
Abstract: [Objective] To accelerate the conversion of rice straw into feeds in the low-temperature region，a microbial community was constructed by continuous enrichment cultivation． Microbial diversity and dynamics during the fermentation at 10℃ was analyzed．［Methods］The community was selected at 5℃ under static condition．To analyze the inoculating effects，the community and commercial inoculant (CI:composed of Lactobacillus plantarum，Enterococcus faecium，L.salivarilus，Pediococcus acidilactici) were respectively inoculated into the rice straw for 30 d fermentation at 10℃．Fermented products were detected by gas chromatography–mass spectrometry (GC-MS)．Composition microorganisms of the community were analyzed using cloning library．Microbial dynamics during the fermentation was detected by denatured gradient gel eletrophoresis (DGGE)．Quantitative PCR was used for tracking the composition microorganisms of the community during the fermentation．［Results］The results from 16S rDNA cloning library showed that the community was mainly composed of Lactobacillus spp. and Leuconostoc spp．At 6d fermentation，the pH and the lactic acid bacterial colony forming units (LAB CFUs) in the fermented rice straw with the community amounted to 4.3 and 2.9×109 CFU/g fresh matter (FM)，respectively．The pH and LAB CFUs with the CI were respectively 5.3 and 2.9×109 CFU/g FM．At 30 d fermentation，the lactic acid concentrations with the community and the CI were respectively 8. 1g / kg FM and 2.0g/kg FM． From DGGE patterns， both L． sakei and Leuconostoc inhae of the community were detected at 6d fermentation and existed during the fermentation． For the treatment with the CI，the uncultured bacterium was detected at 6d fermentation besides the composition microorganisms of the CI． At 16d and 30d fermentation，only L． plantarum and E． faecium were detected． Quantitative PCR showed DNA mass of L． sakei amounted to 41. 0% at 6d fermentation in the treatment with the community． At 16d，DNA mass of L． sakei was 65% ． The highest value (5.5% ) of DNA mass of Le inhae appeared at 6d of fermentation ［Conclusion］ The community could effectively colonize into the rice straw fermentation system and accelerate the fermentation process at low temperature． The dominating microorganism of the community was L． sakei at 10℃ ．

2 Isolation and characterization of a new ε-poly-L-lysine-producing strain TUST-2

Shiru Jia , Chunying Xu , Zhilei Tan , Weifeng Cao , Hongyu Ou , Xinyi He , Zixin Deng

2010, 50(2):191-196.

[Abstract](1698) [HTML](0) [PDF 1.18 M](22411)

Abstract:
Abstract: [Objective] ε-Poly-L-Lysine (ε-PL) is a natural amino acid homopolymer. The study aimed at isolating new ε-PL-producing strains. [Methods] ε-PL-producing strains were screened from the soil by using a new isolation approach which had three steps, (1) enrichment culturing ε-PL toleranting strains; (2) screening by improved Nishikawa’s method; (3) selection of strains with higher ε-PL tolerant ability. [Results]A new ε-PL-producing strain TUST-2 was isolated from the soil collected from Hainan province, China. Chemotaxonomic and morphological characteristics of the isolate were typical of strain of the genus Streptomyces. The strain TUST-2 was found to belong to Streptomyces diastatochromogenes by comparative 16S rRNA gene sequence analysis. The purified fermentation product of the strain TUST-2 was confirmed as ε-PL by characteristic analysis, hydrolysate analysis, infrared spectrum, 1H NMR Spectrum, 13C NMR Spectrum, and MALDI-TOF-MS. [Conclusion] On the basis of 16S rRNA gene sequence analysis and its morphological and physiological characteristics, ε-PL-producing strain TUST-2 is a new isolate of Streptomyces diastatochromogenes, named as Streptomyces diastatochromogenes TUST-2.

3 Identification and antagonistic activities of an endophytic bacterium MGP3 isolated from papaya fruit

Jingying Shi , Aiyuan Liu , Xueping Li , Weixin Chen

2011, 51(9):1240-1247.

[Abstract](1407) [HTML](0) [PDF 938.61 K](17937)

Abstract:
Abstract: ［Objective］Postharvest decay resulted from anthracnose caused by pathogens Colletotrichum gloeosporioides and blight diseases caused by Phytophthora nicotianae leads to significant loss of papaya fruits． In order to reduce such loss，we isolated endophytic bacteria that may possess powerful antagonistic activities toward these pathogens for effective biological control of anthracnose and blight diseases． Methods］The methods of dilution and inhibition circle were used for isolating and screening endophytic bacteria from papaya fruit． Based on morphological，physiological and biochemical characteristics，and homology analysis of the partial sequence of 16S rDNA，an endophytic bacterium was identified．The colonization of the antagonistic endophyte in papaya was detected by inoculating suspension of strains in caudices of papaya plant after Rifampicin-resistant mutants (rifr) induction．The effects on diseases caused by Colletotrichum gloeosporioides and Phytophthora nicotianae were tested by preharvest and postharvest experiments．[Results] One of the endophytic bacteria named MGP3 was selected from the papaya pericarp and identified as Pseudomonas aeruginosa ( Accession No．JF708186)．This bacterium was able to colonize in the laminae，leafstalk or pericarp of papaya，and strongly inhibit 10 phytopathogens． In the postharvest experiment，MGP3 inhibited 50% anthracnose and 71% blight of harvested papaya fruits．The application of MGP3 at five preharvest stages of papaya significantly reduced latent infection rate of Colletotrichum gloeosporioides and disease index of anthracnose．［Conclusion］Antagonistic endophytic bacterium MGP3 isolated from papaya fruit had potential application value as a biological control agent．

4 Characterization of oxysterol binding protein homolog MgORP1 in therice blast fungus Magnaporthe grisea

Chunhua Lin , Fucong Zheng

2008, 48(9):1160-1167.

[Abstract](1487) [HTML](0) [PDF 721.45 K](13857)

Abstract:
[Objective] To study the component of ORPs (Oxysterol-binding proteins-related proteins) family in the rice fungus (Magnaporthe grisea), and the functions of MgORP1 gene with growing development of M. grisea, we constructed two MgORP1 deletion mutants and a complementation mutant. [Methods] All proteins of ORPs have a conserved OSBP-related ligand-binding domain (ORD), which was compared by BLASTP with the sequences of M. grisea genomic DNA published in M.grisea database. One of ORP gene, designated as MgORP1, was deleted by gene replacement and then the phenotypes of △MgORP1 were characterized. [Results] Six putative ORP family proteins have been found in M. grisea, and the growth rate of hyphal colony in complete medium and conidiation of △MgORP1 were lower, whereas the ability of conidia germination, appressoria formation and pathogenicity were normal. [Conclusion] MgORP1 gene of M.grisea was probably involved in colony growth and conidiation.

5 Compound probiotics alleviate cuprizone-induced demyelination in mice

YANG Hao , LI Lin , LIU Qingqing , KANG Xing , YANG Xiaodan , LIU Haixia , FAN Weiping

2022, 62(3):774-784. DOI: 10.13343/j.cnki.wsxb.20210457

[Abstract](453) [HTML](1568) [PDF 15.89 M](13361)

Abstract:
[Objective] To explore the effects of compound probiotics on demyelination of the mice induced by bis-cyclohexanone-oxalyldihydrazone (cuprizone, CPZ).[Methods] Twenty-seven mice were randomly assigned into normal (NC) group, model (CPZ) group, and probiotics group. The mice in the NC group were fed with normal diet, and those in the CPZ group and probiotics group with the diet containing 0.2% CPZ. The mice in the CPZ group and probiotics group were fed with 0.2 mL normal saline and 0.2 mL compound probiotics (7.5 billion colony-forming units) per day, respectively. All the mice were sacrificed after 6 weeks. Luxol fast blue (LFB) staining was employed to observe myelin sheath in the cerebrum. The histopathological change and the expression of mucin and tight junction proteins (ZO-1 and occludin) in ileum and colon were detected by hematoxylin-eosin (HE) staining, Alcian blue staining, and immunofluorescence staining, respectively. The content of lipopolysaccharide (LPS) in brain homogenate was detected by ELISA. The expression of proteins involved in the Toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) signaling pathway was detected by Western blotting.[Results] Compared with the CPZ group, compound probiotics significantly alleviated the demyelination in corpus callosum. In addition, the mice in the probiotics group showed neat and dense ileum villi, increased colon glands, decreased infiltration of inflammatory cells, and up-regulated expression of mucin and tight junction proteins, declined LPS level, and down-regulated expression of TLR4, NF-κB, and P-IκB/IκB in the brain.[Conclusion] Compound probiotics may alleviate CPZ-induced demyelination in mice by reducing intestinal wall permeability.

6 Antiviral mechanisms of interferon-stimulated genes

Siyu Bai , Qian Yang , Huaji Qiu

2018, 58(3):361-371. DOI: 10.13343/j.cnki.wsxb.20170189

[Abstract](1900) [HTML](1723) [PDF 620.95 K](10842)

Abstract:
Interferons (IFNs) can induce the expression of a series of interferon-stimulated genes (ISGs). As direct-acting antiviral factors, ISGs play important roles in host antiviral defense. More and more studies reveal that ISGs directly or indirectly target multiple steps of the virus life cycle. Since diverse ISGs have different structures and locations in the cell, they exert various antiviral actions through different pathways. This review aimed to give a brief introduction to ISGs expression induced by IFNs through the JAK-STAT pathway, and provide an overview of typical antiviral mechanisms of representative ISGs.

7 Research progress in structure, function and inhibition mechanism of NDM-1

Can Cui , Haitao Yang , Zefang Wang

2021, 61(1):41-57. DOI: 10.13343/j.cnki.wsxb.20200133

[Abstract](533) [HTML](2941) [PDF 8.15 M](10540)

Abstract:
In the past decade, metallo-β-lactamases, represented by New Delhi metallo-β-lactamases (NDM-1), have been widely spread around the world, threatening public health and safety. Especially in recent years, the emergence of mutants of these enzymes has caused more complex and difficult challenges to human health. At present, there is still a lack of effective treatment drugs and means. The key to solve this problem is to develop effective broad-spectrum inhibitors of the enzyme. Therefore, we review the three-dimensional structure analysis of NDM-1 and its related inhibitor complexes, to give some inspiration and to help relevant researchers from the perspective of biological mechanism research.

8 Avermectin, from winning the Nobel Prize to “innovation in China”

Jinsong Chen , Mei Liu , Lixin Zhang

2016, 56(3):543-558. DOI: 10.13343/j.cnki.wsxb.20150619

[Abstract](1486) [HTML](674) [PDF 10.77 M](10193)

Abstract:
The uprise of the superpower nations is always accompanied by the breakthrough and advances of technologies and innovations in the history. Natural products play very important role in human health, such as anticancer molecular taxol, anti-infection drug artemisinin that save a lot of lives, metabolic disease treatment, nutrition and health care. However, more has never been explored. With the 2015 Nobel Prize in Physiology or Medicine awarded to William C. Campbell, Satoshi Ōmura, and Youyou Tu for the discovery of avermectins and artemisinin respectively, the second “Golden age” in the development of natural product is dawning. China is a “world factory” and natural drugs-rich country, but how to upgrade and advance the industry and realize the China dream? Avermectins, produced by Streptomyces avermitilis, are pesticide with high efficiency and low levels of side effects. However, the low producer and expensive development pattern of high consumption, high contamination is not sustainable. Solving the problem, increasing the production and utilization of raw material, reducing the energy consumption and cost of production, decreasing environmental pollution are key to transform China into a power house. In this paper, we case-study avermectins to review the industry development driven by fundamental research. Institute of Microbiology, Chinese Academy of Sciences increased the production of avermectin 1000 folds to 9 g/L, which out licensed to new Veyong biochemical Ltd and avermectin Coalitions. As a result, Merck Sharp and Dohme ceased the manufacture of avermectins. The success also shed lights on the improvement of other natural product drugs in China.

9 Identification and biocontrol evaluation of Streptomyces sp.strain ZH-356 antagonistic to plant pathogenic fungi

ZHANG Heng , CHENG Juanli , ZHU Xufei , ZHANG Songlin , YAN Liangwen , LIN Jinshui

2022, 62(9):3421-3436. DOI: 10.13343/j.cnki.wsxb.20220015

[Abstract](236) [HTML](677) [PDF 25.18 M](9877)

Abstract:
[Objective] To identify the laboratory-isolated strain ZH-356 and evaluate its biocontrol effect on plant pathogenic fungi,so as to provide theoretical guidance for the development of biocontrol agents against plant fungal diseases.[Methods] The antimicrobial spectrum of strain ZH-356 and its species were determined by the plate confrontation assay and 16S rRNA gene sequence analysis,respectively.The biocontrol effect of strain ZH-356 was evaluated by the infection prevention test of Valsa malion isolated apple tree branches and the control test of apple valsa canker.[Results]Strain ZH-356 was identified as Streptomyces and had the highest similarity with Streptomyces rectiviolaceus at 99.71%.The antimicrobial spectrum test showed that strain ZH-356 exerted strong inhibitory effect on a variety of plant pathogenic fungi,such as V.mali,Fusarium graminearum,Bipolaris sorokinianumand Alternaria solani,which could lead to the thickening,cross-twisting,infrequent branching and easy fracture of the mycelia of V.mali.In addition,the antimicrobial active substance produced by strain ZH-356 was highly stable to temperature and pH,which only existed in its cells and was secreted in the presence of plant pathogenic fungi to inhibit their growth.In the prevention test of apple valsa canker,strain ZH-356 controlled more than 94% of V.mali infection,and in the control test of apple valsa canker,ZH-356 agents had 100% control of apple valsa canker.[Conclusion] Strain ZH-356 has a wide antimicrobial spectrum and good antagonistic activity against plant pathogenic fungi.It can be used as a biocontrol strain against plant fungal diseases,laying a foundation for the development of ZH-356-based biocontrol agents and the control of plant fungal diseases such as apple valsa canker.

10 Optimization of labeling and localizing bacterial membrane and nucleus with FM4-64 and Hoechst dyes

Jing Wang , Yanping Han , Ruifu Yang , Xingxu Zhao

2015, 55(8):1068-1073. DOI: 10.13343/j.cnki.wsxb.20140603

[Abstract](1397) [HTML](635) [PDF 1.52 M](9229)

Abstract:
Abstract:［Objective］To observe cell membrane and nucleus in bacteria for subcellular localization.［Methods］FM4-64 and Hoechst were dyed that can label cell membrane and nucleus，respectively． Both dyes were used to co-stain the membranes and nucleus of eight bacterial strains ( Escherichia coli，Staphylococcus aureus，Pseudomonas aeruginosa，Klebsiella pneumoniae，Yersinia pestis，Legionella pneumonia，Vibrio cholerae and Bacillus anthracis)． E.coli was dyed with different dye concentrations and times and then observed by confocal fluorescence microscopic imaging.［Results］Fluorescence intensity of cell membrane and nucleus is affected by dye concentrations and times． The optimal conditions were determined as follows: staining cell membrane with 20 μg/mL FM4-64 for 1 min and cell nucleus with 20 μg/mL Hoechst for 20 min．Gram-negative bacteria were dyed better than gram-positive bacteria with FM4-64dye．［Conclusion］FM4-64 and Hoechst can be used to stain membrane and nucleus in different types of bacteria．Co-staining bacterial membrane and nucleus provides the reference to observe cell structure in prokaryotes for studying subcellular localization．

11 16S rRNA gene in community structure analysis and the optimized amplification?A review

Lin Zhou , Jie Zhang?

2010, 50(1):7-14.

[Abstract](1662) [HTML](0) [PDF 1.02 M](8485)

Abstract:
Abstract: The purpose of this review was to offer reference for the study of community analysis in which 16S rRNA was taken as target molecule. We summarized the information of 16S rRNA including its function in cells, transcription organization, the position of variable regions and conserved regions, copies numbers of 16S rRNA gene, secondary structure, some artifacts generated during PCR amplification and the solution to avoid the artifacts.

12 Recent advances in lanthipeptide biosynthesis-A review

Tianlu Mo , Lingui Xue , Qi Zhang

2016, 56(3):373-382. DOI: 10.13343/j.cnki.wsxb.20150427

[Abstract](2173) [HTML](814) [PDF 11.85 M](8347)

Abstract:
Lanthipeptides are a growing class of ribosomally synthesized and posttranslationally modified peptide (RiPP) natural products. These compounds are widely distributed among taxonomically distant species, and their structures and biological activities are diverse, providing an important source for drug research and developement. In this review, we summarized the recent advances in the understanding of structure, classification, evolution and substrate-controlled biosynthetic mechanism of lanthipeptide, attempting to highlight the intriguing chemistry and enzymology in the biosynthesis of this growing family of natural products.

13 Model systems for bacterial biofilm research

LI Jing-bao , HAN Feng , YU Wen-gong

2007, 47(3):558-561.

[Abstract](1585) [HTML](0) [PDF 0.00 Byte](8326)

Abstract:
Contrast to planktonic cells, biofilms are complex communities of microorganisms that develop on biotic or abiotic surfaces. Most of bacteria can form biofilms under proper conditions. Once biofilm form, the inner bacteria cells often exhibit reduced antibiotic susceptibility than their free-floating counterparts, so conventional methods of killing bacteria, such as antibiotics and disinfections are often ineffective with them. Biofilms may cause huge economic loss in equipment damage, product contamination, energy losses and medical infections. Therefore, bacterial biofilm is evolving as a focal problem and an active area of research. As a relatively new area, the progress of biofilm science depends on the development of a satisfactory set of methods. But the classic methods to study planktonic bacteria cannot fulfill the biofilm research, one for which there are few widely accepted methodological standards. Even though biofilms are complicated physical-chemical-biological systems, experience demonstrates that accessible research methods are feasible. In this paper, the theories, principles, merits and limitations of some methods currently used in bacterial biofilm researches, involving artificial biofilm forming and biofilm measurement, were discussed.

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