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Abstract:Using glyphosate as the sole selective pressure, a yeast strain ZM-1 was isolated by enrichment-domestication culture technique from cultivated soils in the suburb around Fuzhou, PR China. The strain was identified as Rhodotorula mucilaginosa based on its physiological, biochemical and 26S rDNA D1/D2 domain sequences analysis. Strain ZM-1 grew with glyphosate as sole carbon and nitrogen source. The maximum glyphosate tolerant concentration for ZM-1 was 50 g/L. Strain ZM-1 was cultivated for 7 d under the conditions that glyphosate concentration 1 g/L, temperature 30°C, and rotation speed 150 r/min with 85.38% glyphosate-degraded rate. With the basal salts medium, the optimal conditions for growth and glyphosate-degraded rate for the strain were as follow: initial glyphosate concentration 1 g/L, inoculating dose 4% (V/V), temperature 30°C, pH value 5.5-6.0 and medium contents 50 mL/250 mL, respectively. Strain ZM-1 could play an important role in bioremediation of glyphosate-contaminated environment, and may be a potential resource in the study of glyphosate-resistant GMO plant.

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Abstract:Methanotrophs are a kind of bacteria which can use methane as the sole carbon source and energy for their anabolism and catabolism. A strain methanotroph was isolated from different samples of the Zoige Plateau, named XN1, and was studied. It was identified a strain of Methylomonas through 16S rRNA sequencing and comparison. The investigation result showed that the optimal conditions for the strain were methane gas together with methanol as carbon source and the coexistence of NH4Cl and KNO3 as nitrogen source, the cultivation temperature of 25°C and medium initial pH of 6.5, and the optional concentrition of CuSO4·5H2O of 0.03 mg/L and FeSO4·7H2O 0.4 mg/L.

Abstract:Soil samples were from the surface of delves 13 and 15 of the Yangling Mausoleum. After cultured in mineral salt media with only sulfur source, five bacterial strains were isolated and assigned as TD1, TD2, TD3, TD15 and PL13. According to their physiobiochemical characteristics and 16S rDNA sequences, TD1, TD3 were identified as Alcaligenes and Bacillus respectively. The ability of metabolizing sulfide was also studied. TD2, TD15 and PL13 can produce a little sulfide. The speed of producing sulfide by TD3 is 1.4 times to that by TD1. These strains feed on sulfide, such as S, S2O32-, S2-, and can oxidize sulfide to sulfate. The conclusion provides a microbiological evidence for the formation of sulfate on the surface of Yangling Mausoleum.

Abstract:Baffled Biological Aerated filter (BBAF) is an innovative biofilter for wastewater treatment. The arm of this work is to investigate the variation of pollutants concentration and microorganism population along the depth of media. Removal efficiency of organic pollutants and ammonia along the media depth of baffled biological aerobic filter were measured. Quantity of heterotrophic bacteria and nitrobacteria in representative depth of media was examined with MPN test, and microorganism population of each filter was studied by means of microscopic observation. The characteristics of microorganism population distribution in BBAF was studied by means of microscopic observation. The results show that COD concentration decreases gradually with the increase depth of media layer. The front four filters have good performance on organic pollutants removal, but performance on ammonia removal is weak, indicating that heterotrophic bacteria is dominating microorganism in these filters. In conditions of lower organic loads bring about a higher growth of nitrobacteria increases the nitrification efficiency in filter five to filter seven. Because the existence of concentration gradient in different filters of BBAF, dominant microorganism population might be formed along the depth of filter media layer and favored the improving treatment efficiency of BBAF.

Abstract:Strain DA09202 with nematicidal activity was isolated from soil sample collected from Hainan Tropical Botanical Garden. Based on the mycelium morphology, physiological property, biochemical property and 16S rDNA phylogenetic tree, strain DA09202 was identified as streptomyces aureus. The results indicated that the strain DA09202 has nematicidal activity, the active compounds A23-1 and A46-2 were purified from its fermentation broth by means of solvent extraction, column chromatography, Sephadex LH-20 and preparation TLC, and the structure of the A23-1 was elucidated as 4￠,7-Dihydroxyisoflavone by spectrum analysis, and the structure of A46-2 is been elucidating.

Abstract:A bacilli-shaped isolate with a unique dual manganese (II)-resistant and manganese (II)-oxidizing activities was screened from the yellow brown soil samples that collected in Queyu, Shandong Province, China. It exhibited a maximum manganese-resistant activity by 130 mmol/L of Mn (II), and a maximum manganese-oxidizing activity by 3.3 μmol/(L·d). This isolated was identified as a Bacillus megaterium strain (named as MB283) according to the morphological, physiological and biochemical characteristics, G + C content as well as the 16S rDNA sequence alignment analyses. Interestingly, the cell growth of MB283 was favored by the low concentration Mn (II) (10 mmol/L). A plasmid-cured mutant strain named as MB287 was obtained by perseveringly incubation of the strain at 43°C and supplementing additionally with 0.01% SDS. It was found that this mutant strain exhibited the proximate Mn (II)-resistant and Mn (II)-oxidizing activities compared to its wild-type strain. Thus, the results indicated that the corresponding genes of manganese resistance/oxidation in MB283 could locate in its chromosomal DNA.

Abstract:A complex microbial system (CMS) RSS-4 with high ability of rice straw degradation was screened and constructed from the soils sampled from fields cultivated with straw-returning techniques for a long term in Sichuan Province by using the restricted cultivation and gradient-temperature induction methods. When RSS-4-induced rice straws degrading experiment was performed at 22°C, the pH value of the system increased at the initial stage and then slightly decreased until to 7.20. The CMC activity and xylan activity also showed an increase at the beginning and followed by an obvious decrease, with the peak values being 0.91 U and 3.40 U, respectively. At the end of fermentation (16 d), the weight of rice straws and the component cellulose and hemicellulose reduced to 45.0%, 55.5% and 44.0%, respectively, while no obvious change happened in the lignin content. It was also found that the RSS-4 by the unsterilized method has better degradation effect than that of the RSS-4￠ by the sterilized method.

Abstract:A total of 40 yeast strains were isolated from 28 traditional fermented congee samples in Inner Mongolia of China. The isolates were identified by analysis of the large 26 subunit (26S) rDNA gene D1/D2 domain sequences. The dominant species was Issatchenkia orientalis (75%, Frequency percentage), followed by Saccharomyces cerevisiae, Geotrichum sp., Candida pararugosa, Candida parapsilosis, Trichosporon asahii, Trichosporon coremiiforme, Candida tropicalis and Clavispora lusitaniae.

Abstract:In this study, α-rhamnosidase activity and naringinase activity were adopted to evaluate effects of conditions on naringinase production by Aspergillus niger DB056. The results showed that fermentation temperature, mycelia morphology, initial pH, inoculation amount and medium volume had important impacts on naringinase production. Optimum conditions, including initial pH 8.0, adding 5 class beads, 45 mL medium in 250 mL flask, inoculation amount 7%, culture temperature 34°C and rotatory speed 190 r/min, were proved superior to get high α-rhamnosidase and naringinase yield. Under these conditions, the enzyme activity detected by high performance liquid chromatography method were 1076.32 U/mL for α-rhamnosidase and 420.68 U/mL for naringinase, which increased by 72.35% and 78.03% comparing with the initial condition. Furthermore, the results also showed Aspergillus niger DB056 could synthesize naringinase not only rapidly in the logarithm grown phase, but also continuously in the stationary and death phase. The present study elucidated effects of fermentation conditions on naringinase production by Aspergillus niger DB056 and provided a preliminarily optimized conditions for naringinase fermentation. It set a basic foundation for further study to enhance the productivity of naringinase by Aspergillus niger DB056.

Abstract:To investigate the differences between the genomes of foot and mouth viruses isolated from cattle and porcine origin, the complete genomes of two strains of Foot-and-mouth disease virus (FMDV), isolated from clinical tissue samples of pig and cattle, were amplified, sequenced and analyzed. The results showed that the genome sizes of the two viruses were 8236 nt in length, including 38-A poly (A) tail. The complete genomic nucleotide and amino acid identity between the two viruses were above 98.0%-99.4%. The phylogenetic tree based on the amino acid sequences of the entire ORF revealed that the Chinese isolates clustered together with the isolates from GroupⅤ. Our results revealed that the complete genome between the viruses from pig and cattle origin had higher homology and some differences that RGD sequence of the 1D-encoding region of isolates from cattle change into RDD, and the amino acid S change into N or D at +9 site in the isolates from pig. The 3A gene had the genetic characteristics from pig. The results lay a foundation for further study of role of the mutated genes in the molecular basis of fitness variations and changes in host cell tropism.

Abstract:Calf pneumonia apostematosa has increased in recent years and major pathogen was Arcanobacterium pyogenes by detecting. The purpose of this study is to develop a PCR method for Arcanobacterium pyogenes diagnosis. A pair of specific primer was designed and synthesized according to 16S rRNA of Arcanobacterium pyogenes. After PCR method was optimized, the specificity and sensitivity was assayed. The specific DNA fragment (927 bp) was successfully amplified with the following condition: 0.2 μmol/L optimal concentration of primer, 58°C anneal temperature and 1.5 mmol/L Mg2+ concentration. The specific test results showed that Arcanobacterium pyogenes could be amplified to obtain 927 bp, however the amplified results of Escherichia coli, Staphylococcus aureus, Bacillus pyocyaneus, Streptococcus pyogenes, Bacillus cereus, Salmonella, Klebsiella pneumoniae and Bacillus proteus were negative. The results of sensitivity test indicated that the minimum detection limits of PCR were 42 Arcanobacterium pyogenes. The PCR diagnosis method of bovine Arcanobacterium pyo-genes was successfully established and this method has high specificity and sensitivity. This research provides new means for the rapid diagnosis of the bovine purulent pneumonia and epidemiological in-vestigations.

Abstract:In order to investigate the potential of pathogens for drug discovery, the secondary metabolites of Edwardsiella tarda were studied. As a result, five indole alkaloids were isolated by column chromatography over silica gel, Sephadex LH-20, and HPLC preparation. By spectroscopic analysis, their structures were identified as bis(1H-indol-3-yl)phenylmethane (1), 1,1-bis(1H-indol- 3-yl)-2-phenylethane (2), (2S)-3,3-bis(1H-indol-3-yl)propane-1,2-diol (3), 1H,1￠H,1￠￠H-3,2￠:3￠,3￠￠- terindole (4), and (3,2￠:2￠,3￠￠-terindolin)-3￠-one (5), respectively. To the best our knowledge, compounds 1, 2 and 4 were isolated as the natural products for the first time. Both compounds 1 and 3 showed weak anti-bacterial activity against Clostridium perfringens with MIC values of 0.125 g/L.

Abstract:To elucidate the relationship among mineral elements, the yield of fruit-body and growth rate of mycelia, effects of mineral elements on the fruit-body yield and growth rate of mycelia of different colony types of Cordyceps militaris in subculturing were investigated. L20, a good strain, was subcultured on different mineral elements media for twelve times with orthogonal experimental method. The results showed that there were seven colony types of L20 after subcultured, among which type Ⅰ, Ⅱ, Ⅲ and Ⅴ had ability to form fruit-body; however, type Ⅳ, Ⅵ and Ⅶ could not. TypeⅠ performed the highest yield of fruit-body, typeⅡ the lowest, and type Ⅲ in mid-level; while all the fruit-body produced by typeⅤ were deformity. The growth rate of mycelia of different colony types were as follow: typeⅤ > typeⅣ > typeⅦ > typeⅥ > typeⅢ > typeⅡ > typeⅠ. The high-production colonies had slower growth rate of mycelia, while the low- production types had over growth of hyphae, indicating there was a negative correlation between the growth of mycelia and fruit-body yield. The formulation of mineral elements, which kept typeⅠhigh yield and maintained more generations was K3Mg2Ca4Mn3Zn2, of which Mn, and K were able to produce high yield of fruit-body; K, Mg and Ca could maintain more generations to produce high yield. The best formulation which suppressed excessive growth rate of mycelia of type Ⅰwas K3Mg2Ca2Mn3Zn2, and Mn had the most significant effect.

Abstract:Two species of Chinese medicinal plants, Salvia miltiorrhiza Bge. and Polygonatum sibiricum Red., were collected from Suining region of Sichuan province. The plants were disinfected with 0.87% hypoclorite under different time and treated with the methods of organic law and homogenate law, respectively. Then endophytes were isolated in the media HV, G2, S amended with which use different concentrations of potassium dichromate plus malidixic acid as inhibitors. The method of isolating endophytic actinomycetes from the medicinal plants was optimized. Fifty-two endophytic actinomycetes with different colony size, shape and color were isolated and purified. Twelve representative strains were chosen for genetic diversity study by 16S rRNA PCR-PFLP. Five clusters were abtained based the 16S rRNA PCR-RFLP pattens which indicated the high genetic diversity of the endophytic actinomycetes in medicinal plants.

Abstract:A mutant of neomycin-producer Streptomyces fradiae was obtained from cultures mutagenized with neutron radiation. Utilizing the mutational strain which can not produce neomycin in normal culture, the biotransformation of neomycin was studied at different conversion conditions. The analysis results of fermentation broth by high performance liquid chromatography showed that the culture conditions such as the concentration of substrate, adding time of substrate, adding method of substrate, inoculation amount, the volume of medium, transformation time, carbon sources, nitrogen sources, pH of media and temperature had different influence on neomycin transformation. The transformation products of neomycin were isolated from a large scale fermentation broth by ion exchange chromatography and identified by thin layer chromatography. The antibacterial activity of four purified samples against Staphylococcus aureus, Erwinia carotovora and Pseudomonas solanacarum were tested by bioautographic analysis. All four samples showed obvious inhibitory activity against Staphylococcus aureus and Pseudomonas solanacarum, but only one sample had inhibitory effect against Erwinia carotovora.

Abstract:To date, the glucose-tolerant β-glucosidase has not been found in prokaryocyte. In the present study, the β-glucosidase gene bg1 from the Agrobacterium tumefaciens str. LBA4404 was cloned into the expression vector pET-28b and transformed into Escherichia coli RP (DE3). Bacteria containing positive clone were routinely grown and IPTG was added to induce the expression of recombinant protein. The β-glucosidase activity of crude extracts was found up to 36.7 μmol/(min·mg). Enzymatic study was performed on the recombinant β-glucosidase purified with Ni column and found that this Bg1 bore high substrate affinity and low substrate specificity, which belonged to the carbohydrate hydrolase superfamily 1. This β-glucosidase displayed quite high activity at pH 5-8 and 40°C, and was able to be stored quite stablely at pH 5-10 and under 40°C. Using pNP-β-Glc as the substrate, the optimum pH and temperature of the hydrolysis reaction were revealed to be 6.4 and 60°C, and the Km of Bg1 was 0.09 mmol/L at pH 6.4 and 37°C. It was inhibited by the competitive inhibitor glucono-δ-lactone (Ki 0.03 mmol/L) and resistant to the inhibition of glucose (Ki 75 mmol/L). We also found that Ag+ and Zn2+ strongly inhibited the activity of Bg1. Its Km for pNP-β-Gal and pNP-α-Glc were respectively 3.61 mmol/L and 14.31 mmol/L.

Abstract:The research of natural yellow pigments from microorganism has been reviewed in this paper, such as the safety and the metabolic mechanism of Monascus yellow pigments, the process controlling for Monascus yellow pigments production and so on. The application prospects and research emphases of Monascus yellow pigment have been discussed; the question in researching of Monascus yellow pigments also has been analyzed.

Abstract:DasR and adjacent DasABC transporter play an important role in both metabolism and morphological differentiation of Streptomyces. In this article we review current understanding of DasRABC in Streptomyces as the followings: structure, regulatory sequence features of DasR and its relationship with DasABC; Function of DasRABC in development and the secondary metabolites of Streptomyces; DasRABC for the uptake of nutrient in Streptomyces.

Abstract:Recently, phytoremediation is considered to be a promising alternative for extraction of heavy metals from polluted soils. Many plant species are useful resources but not tolerant to heavy metals, making it difficult in practical application. Plant growth-promote bacteria are environmental friendly and highly diversity, which will probably facilitate the practical realization of phytoremediation. With the development in technology and resources, bio-regulation will make phytoremediation more viable and more valuable. This paper reviews the emerging bio-regulation technology in recent years, mainly in screening, identification and application of plant growth-promote bacteria.

Abstract:Hundreds of proteins are secreted extracellularly in Ralstonia solanacearum through several specialized protein secretion systems. Key factors to pathogenicity are the type Ⅱ and type Ⅲ secretion systems, both of which are able to export large repertoires of pathogenicity effectors with distinct mechanism. The type Ⅲ secretion system play an important role in host plant recognition as well as in bacteria proliferation, the whole process depend on host microbe interaction and recognition, however, it is Sec signal transduction pathway independent. To date, two groups of type Ⅲ secretion system effectors with host plant targets, named Pop2 and Gala family proteins, have been identified in R. solanacearum strain GMI1000. This review mainly focus on the secretion systems of R. solanacearum and the interaction between host plant target and the type Ⅲ effectors proteins such as Pop2 and Gala family proteins.

Abstract:The General Plant Pathology was one of basic specialty subjects. It was very important to combine theory with practice. In order to culture students ability in innovation, practice and integrative quality we probe into teaching material, classroom teaching, experiment teaching, exercitation teaching, assessment methods and teachers quality. A variety of teaching methods combined with experiment teaching and exercitation teaching lay solid foundation for students to the grass-roots work.

Abstract:Microbiology of Water Treatment is one of the specialized courses of Water Supply and Drainage Engineering. The major objective is to learn and master the basic knowledge and experimental skill of Microbiology and applications of microbes in water treatment field; to arouse the students’ interests in study; to cultivate students’ ability of thinking and solving problems independently; to develop their creative thinking and engineering practice ability. Educational reform of content of courses, teaching methods, and practical teaching on Microbiology of Water Treatment were carried out in the present study, combining with the characteristics of Water Supply and Drainage Engineering and specialized demands for Microbiology of Water Treatment.

Abstract:In this study high temperature (60°C) treatment was used to construct endophyte-free populations of Achnatherum sibiricum (L.) Keng. The results indicated that high temperature treatment was effective in killing the endophyte in the seeds. After 30 days’ treatment, seedlings were all uninfected. At the same time, high temperature treatment had no adverse effect on germination rate, germinating potential and germination index of treated seeds. On the contrary, high temperature improved initial root growth of the treated seedlings. Compared to other methods, high temperature treatment had some advantages such as cost low, procedure simple and environment friendly. Therefore, this method was an effective way to construct endophyte-free populations of Achnatherum sibiricum.