益气养血保元方对小鼠血清溶菌酶及巨噬细胞活性的影响

实验结果显示:生理盐水对照组小鼠的血清溶菌酶含量(μg/ml)为5.31±0.72,益气养血保元方组为7.02±0.44(P<0.01);生理盐水对照组小鼠的MΦ吞噬率(%)及吞噬指数分别为14.58±2.01和0.1826±0.043;益气养血保元方组分别为52.48±4.12及0.7249±0.1222(P<0.01);益气养血保元方组的MΦ中ANAE及ACPasea活性比生理盐水对照组小鼠明显提高。说明益气养血保元方对小鼠血清溶菌酶活性及巨噬细胞活性有正性作用,提示益气养血保元方具有生物反应调节剂BRMs的作用。

大肠埃希菌α溶血素的研究进展

大肠埃希菌α溶血素是RTX毒素家族的典型代表,也是大肠埃希菌肠外感染的重要毒力因子之一。详细介绍了大肠埃希菌α溶血素的成熟、分泌、溶血机理及其生物学效应,这将对大肠埃希菌肠外感染的研究具有重要意义,同时对原核细胞与真核细胞之间的相互作用以及其他细菌溶血素致病机制研究有借鉴作用。

溶菌酶肠溶微球防治肉鸡大肠杆菌病效果观察

为了研究溶菌酶肠溶微球对肉鸡大肠杆菌病的防治效果,试验将240只1日龄体重接近的Ross 308肉仔鸡随机分为空白对照组、阴性对照组、溶菌酶肠溶微球低剂量组(Lem-L组)、溶菌酶肠溶微球中剂量组(Lem-M组)、溶菌酶肠溶微球高剂量组(Lem-H组),每组6个重复,每重复8只。除空白对照组外,其余4组肉鸡于14日龄胸肌接种鸡大肠杆菌;试验期间空白对照组和阴性对照组肉鸡饲喂基础日粮,Lem-L组、Lem-M组、Lem-H组肉鸡分别饲喂添加1.5 g/kg、2.0 g/kg、3.0 g/kg溶菌酶肠溶微球的基础日粮,试验时间为42 d。试验结束时测定每组肉鸡的生长性能,记录发病数、死亡数、病死数,计算发病率、病死率、死亡率、存活率;于第42日清晨无菌取盲肠内容物测定肠道菌群总数。结果表明:1~14 d、1~42 d,与空白对照组和阴性对照组相比,Lem-M组、Lem-H组试验鸡的平均日增重显著提高(P<0.05),料重比显著降低(P<0.05)。与阴性对照组相比,Lem-L组、Lem-M组、Lem-H组试验鸡的发病率、病死率、死亡率均降低,存活率升高。与阴性对照组相比,Lem-L组、Lem-M组、Lem-H组大肠杆菌总数均显著降低(P<0.05),乳酸杆菌、双歧杆菌、肠球菌、芽孢杆菌总数均显著升高(P<0.05);与空白对照组相比,Lem-H组大肠杆菌、梭菌总数显著降低(P<0.05)。说明日粮中添加溶菌酶肠溶微球可以提高被大肠杆菌感染肉鸡的生长性能,改变盲肠微生物数量,降低肉鸡病死率,且溶菌酶肠溶微球添加量为3.0g/kg时效果较好,可用溶菌酶肠溶微球防治鸡大肠杆菌病。

Identification of an Algae-lysing Bacterium of Anabaena flosaquae and Primary Research on Their Relationship

[Objective] The aim was to explore the relationship between alage-lysing bacterium and Anabaena flosaquae so as to provide reference for the control of bloom. [Method] An algae-lysing bacterium strain named S7 was isolated from eu- trophic river. The lyric efficiency and performing mode of S7 strain to Anabaena flos- aquae was studied. Influence of different environmental factors and the relationship between S7 strain and Anabaena flosaquae was also studied, and then the bacteri- um strain was physiologically identified. [Result] More than 90% of Anabaena flos- aquae had been removed by 7 d when the volume ratio of medium to algae solu- tion was 30%, the pH was 9 and the temperature was 35 ℃. These results also showed that a mutual inhibit relationship existed between S7 strain and Anabaena flos-aquae. The S7 strain killed the algae by indirectly through certain lyric agents in absence of direct contact with the target but by secreting metabolites. Moreover, these lyric agents also had the thermostability. 16SrDNA sequence analysis showed that S7 strain belonged to Chryseobacterium sp. [Conclusion] The examined Poly-p proved that S7 strain is polyphosphate accumulating bacteria （PAOs） and has better lyric efficiency.

Lytic Characteristics and Identification of Two Alga-lysing Bacterial Strains

All previously reported bacterial species which are capable of lysing harmful algae have been isolated from coastal environments in which harmful algae blooms have occurred. Due to the low concentration of alga-lysing bacteria in an algal bloom, it is difficult to isolate the alga-lysing bacteria by existing methods. In this paper, two algae-lysing bacterial strains, P01 and P03, have been isolated from a biosystem immobilized on a sponge that was highly effective in removing algae and microcystins. Their lysing modes and effects on Microcystis aeruginosa have been studied. The results show that the degradation processes of these two strains for M. aeruginosa accorded with a first-order reaction model when the chlorophylla concentration was in the range from 0 to 1000 μgL-1. The degradation rate constants were 0.1067, 0.1274 and 0.2792 for P01 and0.0683, 0.0744 and 0.028 97 for P03, when the bacterial densities were 8.6 × 105, 8.6 × 106 and 8.6 × 107cells mL-1 respectively. Moreover, the two bacterial strains had favourable lytic effects not only on M. aeruginosa , but also on Chlorella and Scene-desmus. Their lytic effect on M. aeruginosa did not require physical cell to cell contact, but proceeded by the production of an extracellular product. The bacterial strains were identified as Bacillus species by PCR amplification of the 16S rRNA gene, BLAST analysis, and comparison with sequences in the GenBank nucleotide database.

Phosphorus Solubilizing Capability,IAA Secretion and Characteristics of Phosphorus-solubilizing Bacteria in Rhizosphere of Alfalfa in Guizhou Province

[Objective] The study aimed to isolate and screen efficient phosphorus-sol- ubilizing strains from the root soil of alfalfa in Guizhou, and investigate its growth promoting mechanism. [Method] Phosphorus solubilizing bacteria were isolated from rhizosphere of alfalfa with inorganic and organic phosphorous medium and the strains with higher capacity of dissolving phosphorus were screened through dissolv- ing phosphate zone and further researched. Meanwhile the phosphorus solubilizing capability of strains cultured in liquid medium was investigated by molybdenum blue colorimetric method. [Result] The capacity of dissolving calcium phosphate of 11 se- lected strains differed significantly and tended to be volatile from 150.40 to 268.20 μg/ml; phosphate solubilization capacity, IAA secretion and the pH of culture media did not show any significant correlation; all strains could produce IAA, and the se- cretion was from 12.09 to 22.16 μg/ml; the selected strains all could produce alka- line matter, and most of colonies were pale or milky white, irregular, opaque, jagged, flat and non-pigmented; utilization of carbon sources by different strains varied signifi- cantly. [Conclusion] The study laid the foundation for relieving phosphorus in unpro- ductive land, saving phosphate resources, reducing environmental pollution and pro- viding fertilizer in alfalfa production.

Phosphate-solubilizing microbes in rhizosphere soils of 19 weeds in southeastern China

Low phosphorus (P) availability is one of the most important factors limiting plant growth in red soils across southeastern China. Many non\|symbiotic microorganisms in rhizosphere can enhance P solubility, but little is known about the magnitude of their phosphorus\|solubilizing ability (PSA) and the difference in phosphorus\|solubilizing microorganisms (PSM) among plant species. The number of phosphorus\|solubilizing microorganisms and their PSA in rhizosphere soils of 19 weed species in a citrus orchard on red soil at Changshan, Zhejiang, China, were investigated. Inorganic P (powdered phosphate rock, PR) and organic P (lecithin, OP) were respectively used as the sole P\|source to examine the PSA of isolated microbes. The PS actinomycetes community varied greatly among the different weed rhizospheres while the PS fungus community showed to be most stable to the weed rhizosphere. The highest number of PR\|PS and OP\|PS bacteria was found in rhizosphere soil of \%Mollugo pentaphyll\%, and the highest number of PR\|PS and OP\|PS actinomycetes was found in rhizosphere soil of \%Polygonum lapathifolium\%. The highest number of PR\|PS fungi was found in \%Erigeron annuus\% and \%Mollugo pentaphyll\% rhizosphere soil, and the highest number of OP\|PS fungi was found in rhizosphere soil of \%Mazus stachydifolius\%. \%Mazus stachydifolius\% showed the strongest PR\|PS ability (6340.75μg) while \%Eragrostis pilosa\% showed the strongest OP\|PS ability (1301.84μg). The PR\|PS ability and OP\|PS ability of \%Mollugo pentaphyll\% was 4432.87μg and 1122.05μg respectively. A significant correlation between the number of PR\|PSM and OP\|PSM was found. Significant correlation was only found between the PR\|PS fungi number and its PSA( r =0.75, P <0.05) and between the number of OP\|PS fungi and its PSA( r =0.87, P <0.01}). It indicated that plant species had significant influence on components of the non\|symbiotic PSM community and their activity in its rhizosphere soil. Fungi play a leading role in phosphorus solubilization in weed rhizopshere. It suggested that weed conservation could benefit soil microbe development in agroecosystems, especially in the initial stage of agroecosystem development because there is less organic carbon in bare soil. The results suggested that weed conservation could increase PSA of PSM.

Selection of Rhizosphere Phosphate-solubilizing Bacteria of Perennial Ryegrass

The research isolated phosphorus-soluble bacteria from different parts of ryegrasses and selected 7 bacteria performing better in solbilizing capacity. The test results showed that the capacity of phosphorus-solubilizing tended to be volatile in the range from 135.27 to 187.87 μg/ml and the secreting capacity of IAA was in3.47-24.27 μg/ml. It is believed that Lp59, Lp61, Lp65, Lp69, Lp70 and Lp72 are potential for further development.

Dissolution of antibiotics mycelium in ionic liquids:Performance and mechanism

Antibiotics mycelium, byproduct of pharmaceutical industry, contains high percentage of proteins, polysaccharides and lipids, while, the low solubility in traditional solvents limits its utilization. The dissolution process of penicillin mycelium was investigated using ionic liquids （ILs） as solvent. Quantitative correlation of solubility and ILs structure and dissolution mechanism were determined. About 91 45% of penicillin mycelium was dissolved in 1-butyl-3-methylimidazolium acetate （[Bmim]Ac） under the condition of 120.0℃C and [Bmim]Ac/ mycelium （m/m） ratio of 3.90：1. Synergistic effect of ILs and DMSO was confirmed with the DMSO/[Bmim]Ac （v/m） ratio in the range of 0.0-1.0. At 25.0 ℃, the dissolution of penicillin mycelium increased from 69.74% to 94.50%, with the ratio of DMSO to [Bmim]Ac （v/m） as 1：1. The room temperature dissolution of mycelium provides a novel and energy-saving process for its high-valued utilization. The NMR and FT-IR spectra showed that hydrogen bonds are the dominant driving force for the dissolution in ILs. Quantitative study on the effects of anions and cations of lLs on dissolution using Kamlet-Taft model showed that there was a linearly positive correlation between solubility of penicillin mycelium and β parameter of the ILs. The solubility of mycelium increased with increasing hydrogen bond accepting ability of anions and donating ability of cations.

Screening and Preservation of Douchi Fibrinolytic Enzyme Producing Strain

[Objective] To isolate and preserve a high-activity Douchi fibrinolytic enzyme producing strain from Douchi products. [Method] The Douchi flbrinolytic enzyme producing strain was screened on the selected medium prepared with self-made pork blood powder, the strain with the highest activity was screened out according to the size of hydrolysis cycle, and then preserved in LB medium. [ Rebait] A Douchi fibrinolytic enzyme producing strain with high thrombolytic activity was successfully screened out from the Douchi produced in Hunan, Guangdong and Jiangxi Prov- inces. [ Ceadusioe] The study lays foundation for the development of new-type thrombolytic drugs.

Tyrosinase,a new innate humoral immune parameter in large yellow croaker(Pseudosciaena crocea R)

We evaluated the immune response to infection with a pathogen in large yellow croaker(Pseudosciaena crocea Richardson).The fish were given an intraperitoneal(i.p.) injection of Vibrio parahaemolyticus or sterile sea water(control).We collected blood sera from the fish 0.17,1,2,4,8,12,or 16 d after injection(dpi).We measured tyrosinase activity and the concentrations of lysozyme,NOS,and antibodies.Serum tyrosinase activity was significantly higher at 0.17 and 4 dpi than in the control group,and peaked at 8 dpi.Lysozyme activity was significantly higher at 2 and 12 dpi than in the control group,but lower at 16 dpi.There is no statistical difference in the level of nitric oxides synthase(NOS) activity or antibodies between the control and injection groups.This is the first report of the tyrosinase activity in the serum of large yellow croaker.Our results indicate that tyrosinase plays an important role in the immediate immune defense against V.parahaemolyticus in large yellow croaker.Tyrosinase is a candidate parameter for investigation of fish innate immune defense.

MODELING THE ROLE OF DISSOLVED OXYGEN- DEPENDENT BACTERIA ON BIODEGRADATION OF ORGANIC POLLUTANTS

In this paper, a nonlinear mathematical model is proposed and analyzed to study the role of dissolved oxygen （DO）-dependent bacteria on biodegradation of one or two organic pollutant（s） in a water body. In the case of two organic pollutant（s）, it is assumed that the one is fast degrading and the other is slow degrading and both are discharged into the water body from outside with constant rates. The density of bacteria is assumed to follow logistic model and its growth increases due to biodegradation of one or two organic pollutant（s） as well as with the increase in the concentration of DO. The model is analyzed using the stability theory of differential equations and by simulation. The model analysis shows that the concentration（s） of one or both organic pollutant（s） decrease（s） as the density of bacteria increases. It is noted that for very large density of bacteria, the organic pollutant（s） may be removed ahnost completely from the water body. It is found that simulation analysis confirms the analytical results. The results obtained in this paper are in line with the experimental observations published in literature.