高产柠檬酸突变菌株以玉米粉为原料的生物反应器扩大生产研究

研究目的：研究高产黑曲霉突变菌株以玉米粉为原料的生物反应器扩大发酵,以期获得适合于工业化生产柠檬酸的发酵工艺。 创新要点：以玉米粉为原料,系统地研究了筛选得到的高产菌株在50L生物反应器中不同糖浓度发酵生产柠檬酸的特性,最终优化出适合于工业化生产柠檬酸的发酵工艺。 研究方法：（1）利用淀粉酶对粉碎后的玉米进行液化,然后过滤,最终得上清液;（2）以50L生物反应器作为发酵设备,对筛选得到的高产柠檬酸菌株进行扩大培养;（3）通过测定不同培养时期中积累的柠檬酸含量和剩余的残总糖,最终优化出高效率生产柠檬酸的发酵工艺。 重要结论：以不同糖浓度的液化玉米粉上清液作为碳源,突变菌株H4002能积累177．7--196．0g,L的柠檬酸,效率能达到2．96～3．27g/（L·h）,尤其当糖浓度为210g／L,H4002菌株表现出最佳的柠檬酸生产水平,如柠檬酸积累187．5g/L,生产效率达3．13g／（L·h）。上述结果说明了突变菌株H4002拥有快速生产柠檬酸的能力。     

Medium optimization for enhanced production of cytosine-substituted mildiomycin analogue （MIL-C） by Streptoverticillium rimofaciens ZJU 5119

Cytosine-substituted mildiomycin analogue (MIL-C) was produced effectively by supplementing cytosine into the culture of Streptoverticillium rimofaciens. In order to improve the yield of MIL-C, statistically-based experimental designs were applied to optimize the fermentation medium for S. rimofaciens ZJU 5119. Fifteen culture conditions were examined for their significances on MIL-C production using Plackett-Burrnan design. The Plackett-Burman design and one-variable-at-a-time design indicated that glucose and rice meal as the complex carbon sources, and peanut cake meal and NH4NO3 as the complex nitrogen sources were beneficial for MIL-C production in S. rimofaciens ZJU 5119. The results of further central composition design (CCD)showed that the optimal concentration of glucose, rice meal and peanut cake meal were 18.7 g/L, 64.8 g/L and 65.1 g/L,respectively. By using this optimal fermentation medium, the MIL-C concentration was increased up to 1336.5 mg/L, an approximate 3.8-fold improvement over the previous concentration (350.0 mg/L) with un-optimized medium. This work will be very helpful to the large-scale production of MIL-C in the future.     

植物生长调节物质对玉米根尖愈伤组织培养的影响

以玉米根尖为实验材料，研究不同种类的生长素和细胞分裂素在不同浓度及不同配比下，对愈伤组织培养的影响．通过本研究得出，植物生长调节物质是影响玉米离体根尖愈伤组织培养的重要因素，不同激素种类及不同浓度配比的效果是不一样的．对玉米晴3幼根根尖愈伤组织的培养，2.4-D 2mg／L与BA 1mg／L搭配，效果最好；对玉米大黄幼根根尖愈伤组织的培养，2，4-D 2 mg／L与KT 0．5 mg／L搭配，效果最好．     

Stereoselective glucuronidation of carvedilol by Chinese liver microsomes

Objective: To study the stereoselective glucuronidation of carvedilol (CARV) by three Chinese liver microsomes. Methods: The metabolites of CARV were identified by a hydrolysis reaction with β-glucuronidase and HPLC-MS/MS. The enzyme kinetics for CARV enantiomers glucuronidation was determined by a reversed phase-high pressure liquid chromatogra-phy (RP-HPLC) assay using (S)-propafenone as internal standard after precolumn derivatization with 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosylisothiocyanate. Results: Two CARV glucuronides were found in three Chinese liver microsomes incubated with CARV. The non-linear regression analysis showed that the values of Km and Vmax for (S)-CARV and (R)-CARV enantiomers were (118±44) μmol/L, (2 500±833) pmol/(min·mg protein) and (24±7) μmol/L, (953±399) pmol/(min·mg protein), respectively. Conclusion: These results suggested that there was a significant (P<0.05) stereoselective glucuronidation of CARV enantiomers in three Chinese liver microsomes, which might partly explain the enantioselective pharmacokinetics of CARV.     

<Emphasis Type="Italic">Chryseobacterium chengduensis</Emphasis> sp. nov. isolated from the air of captive giant panda enclosures in Chengdu,China

A Gram-negative, aerobic, non-motile, rod-shaped bacterial strain, designated 25-1^T, was isolated from the air inside giant panda enclosures at the Chengdu Research Base of Giant Panda Breeding, China. Strain 25-1^T grew optimally at pH 7.0–8.0, at 28–30 °C and in the presence of NaCl concentrations from 0.0% to 0.5 %. 16S rRNA gene sequence analysis indicated that strain 25-1^T belongs to the genus Chryseobacterium within the family Flavobacteriaceae and is related most closely to C. carnis G81^T (96.4% similarity), C. lathyri RBA2-6^T (95.8% similarity), and C. zeae JM1085^T (95.8% similarity). Its genomic DNA G+C molar composition was 36.2%. The major cellular fatty acids were iso-C_15:0 (44.0%), iso-C_17:0 3OH (19.8%) and C_16:1 ω7c/_16:1 ω6c (12.7%). The only isoprenoid quinone was menaquinone 6 (MK-6). The major polar lipids were phosphatidylethanolamine, two unidentified amino lipids and two unidentified lipids. The DNA-DNA relatedness between strain 25-1^T and C. lathyri RBA2-6^T was 38%. Phenotypic, genotypic, and phylogenetic characteristics indicated that strain 25-1^T is a novel member of the genus Chryseobacterium, for which the name C. chengduensis sp. nov. is proposed. The type strain is 25-1^T (CCTCC AB2015133^T=DSM 100396^T).     

Medium Optimization for Antifungal Active Substance Production from <Emphasis Type="Italic">Streptomyces Lydicus</Emphasis> Using Response Surface Methodology

Response surface methodology was used to optimize the medium for antifungal active substance production from Streptomyces lydicus E12 in flask cultivation. Initially, the component factors, which influence antifungal substance production, were studied by varying one factor at a time. Starch, soybean cake powder, K₂HPO₄·3H₂O and MgSO₄·7H₂O were found to have a significant effect on the production of antifungal substances by the traditional design. Then, a Box–Behnken design was applied for further optimization. A quadratic model was found to fit antifungal active substance production. The analysis revealed that the optimum values of the tested variable were starch 84.96 g/L, soybean cake powder 4.13 g/L, glucose 5 g/L, MgSO₄·7H₂O 1.23 g/L, K₂HPO₄·3H₂O 2.14 g/L and NaCl 0.5 g/L. The test result of 67.44% antifungal inhibition agreed with the prediction and increased by 14.28% in comparison with the basal medium.     

不同噬菌体类型的谷氨酸高产菌株的选育

本实验采用乳糖发酵短杆菌B_(27-12)作为出发菌株进行试验,首先,通过噬菌体敏感性试验,证明B_(27-12)对天津短杆菌T_(6-13)的五种噬菌体不敏感,从而证明B_(27-12)与T_(6-13)是不同噬菌体类型的谷氨酸生产菌。然后,将B_(27-12)用诱变效率高的原生质体诱变方法进行诱变选育,得到产酸较高的突变株,再进一步通过硫酸二酯(DES)和紫外线复合诱变法进行诱变,选育得到一株产酸较高的突变株D_(16)。     

REVIEWS

Book Reviewed in this article:
W orld P opulation and R esources . P.E.P. Report.
M an on H is P ast . T he S tudy of H istorical S cholarship . By H erbert B utterfield .
D. H. L awrence —N ovelist . By F. R. L eavis .
E xploring E nglish C haracter . By G eoffrey G orer .
T he B ritish W ay of L ife . By K. B. S mellie .
G erman R omantic L iterature . By R alph T ymms .
T he S lave of L ife ; a S tudy of S hakespeare and the I dea of J ustice . By M. D. H. P arker .
N ature in S hakespearian T ragedy . By R obert S peaight .
B ritain B etween the W ars 1918–1940. By C harles L och M owat .     

饲用益生菌的筛选及发酵特性研究

以饲料为原料筛选出一株既产乳酸又产芽孢的益生菌,经过分子生物学鉴定为凝结芽孢杆菌(Bacillus coagulans),命名为T-8。从培养基碳源、氮源、有机物浸出液、培养基pH、培养温度、培养时间等方面对菌株T-8展开发酵特性研究,结果表明,最优培养基配方为:玉米粉6 g/L、豆粕粉15 g/L、小麦麸皮浸出液60%、酵母粉5 g/L、蛋白胨10 g/L、氯化钠10 g/L,pH 5.0。以5%的接种量将种子液转接至最优培养基,在47℃的摇床中以200 r/min的转速振荡培养28 h,菌株T-8的细胞密度达到4.8×10⁹ CFU/mL,芽孢率达到95.2%。本试验可为益生菌凝结芽孢杆菌应用于饲用微生物菌剂的工业化生产提供参考。     

灰树花液体培养基配方的研究

通过正交交互设计试验优化灰树花的液体培养基配方,确定玉米粉和葡萄糖有交互作用,其比例为3∶2时为最优搭配。获得灰树花液体培养的最优配方为黄豆粉2%,玉米粉3%,葡萄糖2%,磷酸二氢钾0.05%,硫酸镁0.2%,豆油0.05%。将灰树花在50L发酵罐中进行深层培养,转速140r/min和通气量为300L/min,菌丝体产量为14.69g/L。     

Adjuvant effects mediated by the carbohydrate recognition domain of <Emphasis Type="Italic">Agrocybe aegerita</Emphasis> lectin interacting with avian influenza H<Subscript>9</Subscript>N<Subscript>2</Subscript> viral surface glycosylated proteins

Objective

To evaluate the potential adjuvant effect of Agrocybe aegerita lectin (AAL), which was isolated from mushroom, against a virulent H₉N₂ strain in vivo and in vitro.

Methods

In trial 1, 50 BALB/c male mice (8 weeks old) were divided into five groups (n=10 each group) which received a subcutaneous injection of inactivated H₉N₂ (control), inactivated H₉N₂+0.2% (w/w) alum, inactivated H₉N₂+0.5 mg recombinant AAL/kg body weight (BW), inactivated H₉N₂+1.0 mg AAL/kg BW, and inactivated H₉N₂+2.5 mg AAL/kg BW, respectively, four times at 7-d intervals. In trial 2, 30 BALB/c male mice (8 weeks old) were divided into three groups (n=10 each group) which received a subcutaneous injection of inactivated H₉N₂ (control), inactivated H₉N₂+2.5 mg recombinant wild-type AAL (AAL-wt)/kg BW, and inactivated H₉N₂+2.5 mg carbohydrate recognition domain (CRD) mutant AAL (AAL-mutR63H)/kg BW, respectively, four times at 7-d intervals. Seven days after the final immunization, serum samples were collected from each group for analysis. Hemagglutination assay, immunogold electron microscope, lectin blotting, and co-immunoprecipitation were used to study the interaction between AAL and H₉N₂ in vitro.

Results

IgG, IgG1, and IgG2a antibody levels were significantly increased in the sera of mice co-immunized with inactivated H₉N₂ and AAL when compared to mice immunized with inactivated H₉N₂ alone. No significant increase of the IgG antibody level was detected in the sera of the mice co-immunized with inactivated H₉N₂ and AAL-mutR63H. Moreover, AAL-wt, but not mutant AAL-mutR63H, adhered to the surface of H₉N₂ virus. The interaction between AAL and the H₉N₂ virus was further demonstrated to be associated with the CRD of AAL binding to the surface glycosylated proteins, hemagglutinin and neuraminidase.

Conclusions

Our findings indicated that AAL could be a safe and effective adjuvant capable of boosting humoral immunity against H₉N₂ viruses in mice through its interaction with the viral surface glycosylated proteins, hemagglutinin and neuraminidase.

     

甘蔗糖蜜发酵培养富铁营养酵母菌种筛选

对3种共25株酵母菌进行了富铁能力的筛选,经过抗性筛选和摇瓶发酵培养筛选到一株生物量及细胞铁含量均较高的酵母菌株R4-5,该菌株能以甘蔗糖蜜作为唯一碳源发酵培养富铁酵母,在培养条件下,生物量为8.78 g/L发酵液,细胞铁含量为5.45 mg/g干菌体,总铁含量达47.851 mg/L发酵液。     

Chemical composition and antioxidant activity of certain <Emphasis Type="Italic">Morus</Emphasis> species

In the present work, the fruits of four Morus species, namely Morus alba (white mulberry), Morus nigra (black mulberry), Morus laevigata (large white fruit), and Morus laevigata (large black fruit), were analyzed for proximate composition, essential minerals, and antioxidant potentials. For this purpose, the ripe fruits were collected from the northern regions of Pakistan. The major nutritional components (moisture, ash, lipids, proteins, fibres, carbohydrates, and total sugar) were found to be in the suitable range along with good computed energy. Total dry weight, pH, and titratable acidity (percent citric acid) were (17.60±1.94)–(21.97±2.34) mg/100 g, (3.20±0.07)–(4.78±0.15), and (0.84±0.40)%–(2.00±0.08)%, respectively. Low riboflavin (vitamin B₂) and niacin (vitamin B₃) contents were recorded in all the fruits, while ascorbic acid (vitamin C) was in the range from (15.20±1.25) to (17.03±1.71) mg/100 g fresh weight (FW). The mulberry fruits were rich with regard to the total phenol and alkaloid contents, having values of (880±7.20)–(1650±12.25) mg/100 g FW and (390±3.22)–(660±5.25) mg/100 g FW, respectively. Sufficient quantities of essential macro-(K, Ca, Mg, and Na) and micro-(Fe, Zn, and Ni) elements were found in all the fruits. K was the predominant element with concentration ranging from (1270±9.36) to (1731±11.50) mg/100 g, while Ca, Na, and Mg contents were (440±3.21)–(576±7.37), (260±3.86)–(280±3.50), and (240±3.51)–(360±4.20) mg/100 g, respectivly. The decreasing order of micro-minerals was Fe>Zn>Ni. The radical scavenging activity of methanolic extract of fruits was concentration-dependent and showed a correlation with total phenolic constituents of the respective fruits. Based on the results obtained, mulberry fruits were found to serve as a potential source of food diet and natural antioxidants.     

Genotype-phenotype correlations in Chinese patients with TGFBI gene-linked corneal dystrophy

In this paper, we report the clinical and molecular features of the distinct TGFBI (human transforming growth factor β-induced, OMIM No. 601692) gene-linked corneal dystrophy. Altogether, five pedigrees and ten unrelated individuals diagnosed as corneal dystrophy were recruited. Peripheral venous DNA was extracted, and then amplified by polymerase chain reaction (PCR) and scanned for mutation by single-stranded conformation polymorphism (SSCP). Direct DNA sequencing was used to analyze the mutations of the TGFBI gene. In our study, thirty patients from five pedigrees and ten sporadic patients were diagnosed as four TGFBI gene-linked corneal dystrophies of granular corneal dystrophy type I (GGCD I), Avellino corneal dystrophy (ACD), lattice corneal dystrophy type I (LCD I), and lattice corneal dystrophy type IIIA (LCD IIIA), and in total, seven disease-causing mutations, namely R555W, A546D, A546T, and T538P mutations in exon 12, R124H and R124C mutations in exon 4, and P501T mutation in exon 11, were identified, while four polymorphisms of V327V, L472L, F540F, and 1665-1666insC were screened in exons 8,11, and 12. The study ascertained the tight genotype-phenotype relationship and confirmed the clinical and genetic features of four TGFBI gene-linked corneal dystrophies.     

水杨酸对铅胁迫下玉米幼苗生理特性的影响

以玉米种子为试验材料,采用砂培法研究了水杨酸(SA)对铅(Pb2+)胁迫下玉米种子的萌发、叶绿素含量、MDA含量、POD活性、等方面的影响。结果表明:低浓度的SA≤80mg/L时,能促进铅胁迫下玉米幼苗的生长,表现为玉米种子的发芽率增大,幼苗根长的增加,叶绿素含量增大,MDA的含量降低,POD活性升高,等。当SA浓度为60mg/L～80mg/L,Pb2+≤1mg/L时,SA对Pb2+的解毒效应最明显,当SA浓度为100mg/L,Pb2+为8mg/L时,SA与Pb2+协同迫害幼苗的生长。     

平面上拟线性偏微分方程组弱解的有界性

本文假定通常的椭圆条件仅在无穷远处成立,证明了平面上一类二阶拟线性偏微分方程组弱解是有界的。     

矩阵损失下期望向量的非齐次线性可容许估计

:设Y1 ,Y2 ,… ,Yn 独立同分布 ,EY1 =β ,DY1 =V ,这里 β∈Rm 与V :mxm >0均未知。取矩阵损失函数L(d ,β) =(d - β) (d - β)′ ,估计类￡ =∑ni =1LiYi+b ;Li 为m阶方阵 ,i=1,… ,n ;b∈Rm 。本文在矩阵损失下给出了非齐次线性估计在￡中是 β的可容许估计的充要条件     

化合物(NIT-1′-MeBzIm)_2·(H_3bta)的合成及晶体结构

本文合成了一个新的化合物C39H44N8O10:(NIT-1′-MeBzIm)2.(H3bta)(NIT-1′-MeBzIm=2-{2′-[(l′-甲基)苯并咪唑]}-4,4,5,5-四甲基咪唑啉-3-氧化-1-氧基自由基,H3bta=1,2,4-苯三酸),并测定了其晶体结构.该晶体属三斜晶系,P1空间群,晶胞参数:a=7.372(12),b=8.705(15),c=15.65(3),α=100.81(3)°,β=97.47(3)°,γ=101.55(2)°,V=952(3)3,Z=1,Dc=1.369 mg/m3,最终偏差因子R1=0.1047,WR2=0.2650(I>2σ(I)),F(000)=414.该化合物通过分子间氢键和π-π堆积作用形成二维网状结构.     

Optimization of conditions for supercritical fluid extraction of flavonoids from hops (Humulus lupulus L.)

INTRODUCTION The hop plant (Humulus lupulus L., Cannabi- naceae) is a dioecious twining perennial widely cul- tivated throughout the temperate zones of the world. The inflorescences (hops or hop cones) are used in breweries to give beer its characteristics such as fla- vor and aroma. In this respect, the bitter acids and essential oils have received much attention. Carbon dioxide (CO2) is currently the most accepted solvent for the manufacture of hops extracts by breweries. Its extracts…     

Antioxidant power of phytochemicals from<Emphasis Type="Italic">Psidium guajava</Emphasis> leaf

Dried ground leaves ofPsidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1∶10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to Folin-Ciocalteu's phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3±15.5 and 511.6±6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts, respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH') colorimetry with detection scheme at 515 nm. The activity was evaluated by the decrease in absorbance as the result of DPPH' color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC₅₀ and the time needed to reach the steady state to EC₅₀ concentration (T _{EC 50}) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more adequate parameter for selecting antioxidants than the widely used EC₅₀. This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants.