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Abstract:In order to investigate molecular diversity of bacteria community from both a normal arable soil (Nor-1) and an arsenic and sulphate polluted soil (Sul-1). Environmental total DNA was directly extracted from two soil samples. The 16S rRNA genes were amplified from the total DNA and construction a clone library. Positive clones were randomly selected from the library and identified by amplified ribosomal DNA restriction analysis (ARDRA) and sequencing, then constructed phylogenetic tree. 23 unique clone sequences from Nor-1 soil were classified into 5 bacterial phylum including Acidobacteria (12.3%, 8/65), Actinobacteria(3.1%, 2/65), Firmicutes (21.5%, 14/65), Nitrospira (3.1%, 2/65) and Proteobacteria (60%, 39/65), while 19 unique clone sequences from Sul-1 soil were classified into 2 bacterial phylum including Firmicutes (29.5%, 13/44), and Proteobacteria (70.5%, 31/44). The result suggested that the high concentration of arsenic and sulphate influenced the bacterial population of Sul-1 soil leading to construction of obviously specific bacteria community. Interestingly, a lot of Acinetobacter related sequences have been detected in Sul-1 soil bacteria community including clone Sul11/15, Sul12/7 and Sul12/11. Because Acinetobacter strains are often ubiquitous, exhibit metabolic versatility, those related strains may be good targets for exploiting novel arsenic detoxification bacteria.

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Abstract:Manganese oxides are a type of high-reactive minerals that formed from biochemical and chemical oxidations of manganese(Ⅱ), which are capable of influencing significantly the transport and fate of many major and trace elements in the biogeochemical cycles. Increasing evidence is showing that microorganisms, especially a variety of bacteria, play a dominant role in the oxidation of dissolved Mn(Ⅱ) in natural systems. In this study, a soil-borne bacterial isolate with a maximum manganese-oxidizing activity by 65 μmol/L (it was apparently higher than that of other isolates by using the standard leucoberbelin blue assay procedure), was screened from the Fe/Mn nodule-surrounding brown soil samples that taken in Queyu, Shandong Province, China, and was identified as an Escherichia coli strain (named as MB266) according to the morphological, physiological and biochemical characteristics, G+C content of its genomic DNA as well as the 16S rRNA gene sequence alignment analysis. Subsequently, the multicopper oxidase encoding gene (mco) of MB266, which was thought to involve in manganese(Ⅱ) oxidation, was cloned and characterized (GenBank accession number: JF682492). It showed that the corresponding protein, MCO, was highly similar (by 99.0%) with the previously reported E. coli-harboring type Ⅲ multicopper oxidase at their amino acid sequences, whereas the similarity of amino acid sequences was very limited (by only 19.2%) with a currently well-characterized bacterial manganese oxidase, manganese oxidase CumA of Pseudomonas putida MnB1. However, the conserved structural domain analysis using online tool CDART revealed that two conserved copper-oxidizing super family domains in both proteins, together with two conserved Cu(Ⅱ)-binding sites in each conserved domain. Additionally, it appeared that multiple b-sheets in both proteins that were able to form b-barrel domains in their predicted secondary structures. Thus, the structural intercommunity between MCO and CumA might contribute to their similar biochemical activities in manganese oxidation. The manganese-oxidizing activity of an E. coli wild-type strain is a distinctive feature that has not been reported prior to this study.

Abstract:Hoh Xil, an extremophile environment situated at the Yushu Tibetan Autonomous Region in southwest Qinghai, is one of the most primitive and well-preserved natural environment on earth. The microbial diversity in this area is poorly known till date. In this present study an attempt has been made to selectively isolate the alkalophilic microorganisms in 12 salina soil samples from Hoh Xil, by using five different medium. As a result, 5 alkaliphilic or salkaline tolerant isolates were obtained. 16S rRNA gene sequence analysis showed that 4 strains belonged to 4 different genera, such as Planomicrobium, Kocuria, Aerococcus, and Bacillus. Another strain, designated CPCC 100153 was the nearest to the genus Geomicrobium, showing the 16S rRNA gene sequence similarity level of 93.5 % to the strain Geomicrobium halophilum BH1T. Based on the phenotypic characteristics, physiological and biochemical tests, chemotaxonomic analysis and genotypic data, we found that the strain CPCC 100153T not only shared some common characteristics with the alkaliphilic or salkaline tolerant species of the related genus in the family Bacillaceae but also clearly differentiated from them. Therefore, we propose the strain CPCC 100153T represents a novel genus and species within the family Bacillaceae.

Abstract:L-lactate dehydrogenase (L-LDH) is a key enzyme which catalyzes the formation of L-lactate from pyruvate in the Lactobacillus sp.. The gene ldhL encoding L-LDH was amplified from genome DNA of Lactobacillus casei using PCR technique. The PCR product was cloned into pUcm-T vector and double digested with restriction endonucleases, and then the DNA fragment of ldhL was inserted into pET-28a(+). The recombinants expression plasmid pET-ldhL was obtained, and was transformed into E. coli BL21. After it was induced to express L-LDH with IPTG, and purified by affinity chromatography. SDS-PAGE showed that the molecular weight of specific fusion protein was 40 kD. The biochemical properties of L-LDH showed that the specific activity were up to 1 722 U/mg with optimum catalysis temperature of 40 °C?45 °C and pH of 6.6?6.8. Fructose-1,6-bisphosphate (FBP) is a positive allosteric modifier of the enzyme, the addition of Mn2+ to the assay in the presence of FBP broadens the pH profile, particularly towards neutral pH values. Mn2+, Ca2+ and Mg2+ increases the activity of L-LDH, but Zn2+ decreases its activity.

Abstract:After preliminarily isolated from soil of vegetable gardens by using blood-agar method, eight strains were further examined by oil-spreading test and inhibitory test. Primers were designed according to genes (sfp, ituD, lpa-14) related to surfactin and iturinA synthesis, and one bacterial strain XZ-173 with a broad spectrum of phytopathogens was screened out by PCR of the sfp, ituD, lpa-14 gene. Based on the physiological and biochemical properties and 16S rDNA sequence analysis, it was identified as Bacillus amyloliquefaciens. The FT-IR and HPLC results indicated that the biosurfactnat produced by strain XZ-173 was lipopeptides that contained surfactin and iturin A. The prepared crude lipopeptides reduced the surface tension of water to 26.6 mN/m with a critical micelle concentration (CMC) of 500 mg/L and showed stable emulsification capability and strong inhibition against Rhizoctonia solani and Ralstonia solanacearum. Lipopeptide-producing stain XZ-173 had potential to be used in biological control of soil-borne plant diseases.

Abstract:In this study, the major pathogens that caused soft rot disease of imported dragon fruit were studied morphologically and molecularly. Two strains of Fusarium were identified in this study, which respectively belongs to Fusarium oxysporum and Fusarium dimerum. F. oxysporum was the most important pathogen which caused postharvest rot on imported pitaya. The most optimum temperature for F. oxysporum growth and pathogenicity was 25 °C. In addition, there was a positive relationship between pathogenicity and illumination. It could neither grow nor form lesion under lower temperature (5 °C) and higher temperature (45 °C), its pathogenicity became weaker under 15 °C and 35 °C. Further analysis showed that it could also cause postharvest rot on banana, tomato and grape. Taken together, our results analysis the key pathogen caused postharvest rot on imported pitaya and provide a useful reference for making measures towards the disease.

Abstract:In this study, a pseudovirus system was constructed to investigate the anti-HIV mechanisms of five natural compounds. Three plasmids containing backbone, gag-pol of HIV-1 and VSVG were transfected to 293T cells to produce pseudotyped HIV-1 virus. Real-time PCR assay was used to explore the targets of these compounds by testing the specific viral products in the early life cycle of HIV-1. With this system, the targets of four compounds have been initially identified. LC-1 and LC-2 could block the nuclear import of HIV-1preintegration complex (PIC) into the nucleus. LC-3 could inhibit viral DNA integration to host genome. LC-4 could inhibit the activities of reverse transcriptase. Compounds LC1 and LC2 showed different action target from the existing drugs. Further study has been carried to explore the new potential action mechanism. This study showed that the pseudovirus system we constructed can be used as an assay platform to screen anti-HIV drugs.

Abstract:Mucopolysaccharide was made of uronic acid and hexosamine. Due to the unique physical and chemical properties, mucopolysaccharides have been used in various fields. After collecting and enrichment culture of active nasal mucosa scraped from newly slaughtered cattle, we got a kind of streptococcus zooepidemicus which was named BU100. With its culture it can secrete a high yield new Mucopolysaccharide A. As there were uronic acid and hexosamine in mucopolysaccharide, the methods of carbazole and Elson-Morgan were used to detect mucopolysaccharide A. In addition, the major impurity (protein) in mucopolysaccharide was detected by the method of Coomassie brilliant blue. According to these methods, it was found that the ratio of uronic acid and hexosamine in mucopolysaccharide A was nearly 1:1 which was the same as that in Hyaluronic Acid (HA), and the quantity of protein meets the standards (<0.1%) requirements. Furthermore with the IR, NMR, the functional group of mucopolysaccharide A was determined and compared to HA. It therefore indicates that most structure and functional group in mucopolysaccharide A were nearly as the same as that in HA. As there were uniqe properties in mucopolysaccharide A, a lot of properties were detected, such as moisture absorbtion, moisture retention, reducing power, clearance of hydroxyl radical, resistance of hyaluronidase. These properties of mucopolysaccharide A were also compared with that of HA. The results showed that the clearance of hydroxyl radica, moisture retention, and reducing power of mucopolysaccharide A was better than HA, but the absorbtion rate of mucopolysaccharide A was not as well as that of HA, and mucopolysaccharide A could resist to Hyaluronidase. Because the structure and functional group of mucopolysaccharide A was highly similar to HA, meanwhile some characters of mucopolysaccharide A were superior to HA, the conclusions was that mucopolysaccharide A can be more effectively applied in medical, cosmetics, etc.

Abstract:Five endophytic bacteria containing ACC-deaminase were isolated from the roots of Eucommia ulmoides Oliver based on their ability to utilize ACC as a nitrogen source, and their antibacterial activities were determined by using the agar disc diffusion test. Identification of these isolates was determined by their morphological, physiological-biochemical properties and phylogenetic analysis based on 16S rRNA gene sequences. The ACC deaminase activity assay demonstrated that the five endophytic bacterial isolates expressed the ACC deaminase activity, and four isolates of them displayed antibacterial activity against Escherichia coli CGMCC1.1103 and Bacillus subtilis CGMCC1.769, respectively. Five ACC deaminase-containing endophytic bacteria isolates named as JDM-2, JDM-8, JDM-11, JDM-14 and JDM-19 were identified as Pseudomonas koreensis, Klebsiella pneumoniae, Enterobacter ludwigii, Klebsiella variicola and Enterobacter asburiae, respectively.

Abstract:The antioxidant activities in vitro of polysaccharides from Cantharellus cibarius, Russula virescens, Tricholoma myomyces and Armillaria mellea were evaluated by testing their DPPH radical scavenging activities, hydroxyl free radical scavenging activities, ferrous ion chelating ability and reducing activity. The results showed that the crude polysaccharides from T. myomyces and A. mellea had the most potent capacity for scavenging DPPH with EC50 values reaching 1.35 g/L and 1.53 g/L, and they were superior to the other two fungi in the scavenging hydroxyl radical capacity, with EC50 values reaching 0.65 g/L and 0.78 g/L, respectively. The polysaccharide from T. myomyces showed the most potent ferrous ion chelating ability with EC50 values reaching 1.69 g/L. In respect to the potent capacity for reducing power, the polysaccharide from T. myomyces showed the most potent capacity with EC50 values reaching 1.05 g/L, followed by that of A. mellea with EC50 values reaching 1.37 g/L.

Abstract:Streptomyces xinghaiensis is a novel Streptomyces species isolated from marine sediment sample collected in Xinghai Bay, Dalian, China, and wide spectrum of antimicrobial activities of its fermentation broth has been observed. In this study, the antibacterial activities of the fermentation broth of S. xinghaiensis against drug-resistant clinical isolates were investigated, and inhibitory activities against Acinetobacter baumannii and Staphylococcus aureus (MRSA) strains were revealed. Purification of the active compound (s) against methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates was performed and the properties of the active compounds were studied. Active fractions were obtained after treatments of the broth with macroporous adsorptive resin HP-20 and Sephadex LH-20. The active components were weak alkaloid compounds with no specific UV adsorption, and ninhydrin coloration further supported the hypothesis that the active compounds likely belong to aminoglycoside antibiotics. The draft genomic sequence of S. xinghaiensis was searched and a ribostamycin-related gene cluster was identified. However, Thin Layer Chromatography (TLC) analysis indicated that the major components of the active compounds are different from ribostamycin.

Abstract:To elucidate the systemic gene expression variation and virulence gene regulation of Pseudomonas aeruginosa in hyperbaric oxyhelium exposure environment. The level of differential gene expression was analyzed by PAO1 genomic DNA chip and 5 strikingly up-regulated genes were confirmed by RT-PCR. The level of elastase was detected by spectrophoto-metric method. Microarrays analysis showed that the expression levels of 243 genes were altered after 12 hours exposure and 1 168 genes altered after 72 hours exposure under the hyperbaric oxyhelium condition. These genes are mainly related to stress-sense/response, protein folding, transcriptional regulation, pili and flagellum metabolism, virulence factors adaptation, membrane proteins or antigens metabolism. The results of RT-PCR showed the same expression trends as in the micro-array. The ability of bacterial infection also increased after 72 hours exposure. Based on the results, we concluded that the hyperbaric oxyhelium environments affected PAO1 genes expression and several virulence-related genes were up-regulated.

Abstract:NaCl stimulation affects the activity of phosphofructokinase (PFK) and survival rate of freeze-dried Lactobacillus bulgaricus. In the late logarithmic phase, adding 2% (W/V) NaCl to the growth medium markedly increased the survival rate of freeze-dried L. bulgaricus. Meanwhile, the activity of PFK in L. bulgaricus after NaCl stimulation was determined by reversed phase high performance liquid chromatography (RP-HPLC). The results showed that PFK activity was increased significantly by NaCl stimulation. In addition, a semi-quantitative RT-PCR method was applied to detect the PFK gene expression in different condition. The results indicated that the PFK gene expression was increased before freeze-drying and almost unchanged after freeze-drying. NaCl stimulation could enhance the survival rate of freeze-dried cells, and PFK might affect the survival of Lactobacillus bulgaricus.

Abstract:The outbreaks of foodborne disease caused by foodborne pathogens are happened frequently and have a hazardous impact on public health, especially the emergence of antibiotic-resistant pathogens which may cause the failure of regular antimicrobial therapy. The discovery and application of bacteriophages and their lysins opened up a new path for detection and biocontrol of foodborne pathogens. This review intends to briefly summarize the application of bacteriophages and their lysins for constructing the rapid detection methods and biocontrol of foodborne pathogens.

Abstract:In this paper, the teaching reform in the Biotechnology course presented in the Bioengineering Department of the Inner Mongolia University of Technology was discussed. In order to stimulate students’ interest in learning, train students’ abilities in studying and develop their team spirit, “Course design” and “Semi-self-help teaching model” were introduced into the Biotechnology course. In practice teaching section, “Specialty experiment” and “Comprehensive training” were employed to strengthen students’ abilities in operation and engineering practice. Through the practice of a few years, the teaching of Biotechnology has been improved constantly. The teaching reform has reached a good teaching effect.

Abstract:This paper discussed about the course system construction and the practical teaching of Microbiology. The practical teaching was strengthened by optimizing the teaching program of Microbiology, constructing the perfect practical teaching systems, and strengthening the construction of practical bases. The students’ interest in Microbiology was stimulated, and their practical skills and comprehensive abilities were also enhanced by reforming the teaching methods. The teaching effectiveness was improved too.

Abstract:This thesis presents a series of changes during the process of developing “Protein & Enzyme Engineering” into a university’s essence course, including: structural adjustment of content, combination of old and new teaching methods, innovation of examination method and practical teaching, to give students the right to choose learning content, teaching methods, examination type and its evaluation. The study tends to make the students fully developed and experiences being accumulated in teaching reform.

Abstract:Conditioned pathogen was a basic concept widely used in domestic medical microbiology textbook. However, there were obvious defects both in the establishment and application of this concept. And which might make students misunderstand and be ambiguous when learn some essential fundermental cocepts, such as symbiotic microbial community in the human body and conditioned pathogen. So here we offer some initial ideas for discussion, and hope a more faultless and suitable formulation could be made by learning from each other.

Abstract:We attempted to reform the conventional models of clinical microbiology experimental teaching, and organized students to finish experiments in hospitals or companies. In accordance with the microorganism clinical laboratory workflow, experiment teaching divided into three project, inoculation, culture and identification of bacteria. We organized students and company’s employees a thorough exchange, experienced enterprise culture atmosphere, felt humanities concern. As a result, improves the quality of experiment teaching, lets the student set up the more scientific and reasonable employment mentality.