鼠白细胞介素12（mIL—12）在昆虫细胞中的表达

Since human IL-12 is species-specific in its functions and elicits little biological responses from mouse lymphocytes, it is necessary to express recombinant murine IL-12 for the usage in studying the effects of this cytokine in various rodent models. Thereby, we can investigate the role of IL-12 in immune response in vivo and evaluate its potential clinical utility. Thus, we firstly constructed two expression vectors, pVL1393-mp40 and pVL1393-mp35. They were used to co-transfect the insect cells(Sf9) separately with linearized polyhedrosis virus genomic DNA. Two kinds of recombinant viruses AcNPV-mp40 and AcNPV-mp35 were visually screened out, and mp40 and mp35 were co-expressed in the insect cells co-infected by AcNPV-mp40 and AcNPV-mp35. The results of real-time Biomolecular Interaction Analysis (BIA) and Northern blot demonstrated that the recombinant mIL-12 was expressed successfully in the insect cells. The molecular weights of recombinant mp40 and mp35 were 40 KDa and 22 KDa on SDS-PAGE under reducing conditions, respectively. The apparent molecular weight of recombinant mIL-12 is 80 KDa under non-reducing conditions of Western blot. Biological activity of the recombinant product was detected in conditional medium using antibody-capture bioassay. The expression level of recombinant mIL-12 was about 10-15 micrograms/10(6) cells, as compared with the calibration curve of mIL-12.     

The Neurospora rca-1 gene complements an Aspergillus flbD sporulation mutant but has no identifiable role in Neurospora sporulation.

The Aspergillus nidulans flbD gene encodes a protein with a Myb-like DNA-binding domain that is proposed to act in concert with other developmental regulators to control initiation of conidiophore development. We have identified a Neurospora crassa gene called rca-1 (regulator of conidiation in Aspergillus) based on its sequence similarity to flbD. We found that N. crassa rca-1 can complement the conidiation defect of an A. nidulans flbD mutant and that induced expression of rca-1 caused conidiation in submerged A. nidulans cultures just as was previously observed for overexpression of flbD. Thus, the N. crassa gene appears to be a functional homologue of A. nidulans flbD and this is the first demonstration of functional complementation of an A. nidulans sporulation defect using a gene from an evolutionarily distant fungus. However, deletion of the rca-1 gene in N. crassa had no major effect on growth rate, macroconidiation, microconidiation, or ascospore formation. The only phenotype displayed by the rca-1 mutant was straight or counterclockwise hyphal growth rather than the clockwise spiral growth observed for wild type. Thus, if rca-1 is involved in N. crassa development, its role is subtle or redundant.     

Production of poly-β-hydroxybutyrate on molasses by recombinant Escherichia coli

Beet molasses successfully replaced glucose as sole carbon source to produce poly--hydroxybutyrate by a recombinant Escherichia coli strain (HMS174/pTZ18u-PHB). The fermentation with molasses was cheaper than with glucose. The final dry cell weight, PHB content and PHB productivity were 39.5 g/L, 80% (w/w) and 1 g/Lh, respectively, in a 5 L stirred tank fermenter after 31.5 h fed-batch fermentation with constant pH and dissolved O2 content. © Rapid Science Ltd. 1998     

棉铃虫对Bt生物农药早期抗性及与转Bt基因棉抗虫性的关系

用饲料感染法建立了棉铃虫Helicoverpa rmigera(Hubmer)敏感品系(SUS1)对Bt生物农药的敏感毒力基线和区分剂量,1995年测定了五省六县棉铃虫初孵幼虫对Bt生物农药的敏感性,结果表明：山东阳谷、河北邯郸、河南新乡、安徽萧县及江苏丰县棉铃虫已产生早期抗性,抗性个体百分率为5%～10%,与敏感品系相比,LC₅₀值稍有增加,但斜率b值明显变小;而江苏东台棉铃虫仍属敏感。这是国内外首次诊测到棉铃虫对Bt生物农药抗性。用棉叶喂饲法测定比较了转Bt基因棉花品系对不同种群棉铃虫的抗虫性效果,结果表明：用早期抗性的阳谷和新乡棉铃虫初孵幼虫接虫5d后平均死亡率较敏感品系下降16%～29%,说明棉铃虫对Bt农药与转Bt生物基因棉花品系间存在交互抗性。还讨论了Bt农药的抗性治理对策。     

味觉的生理学研究进展

味觉的生理学研究进展陈建国（江苏省启东肝癌研究所,启东２２６２００）沈福民（上海医科大学遗传医学研究中心,上海２０００３２）目录一、味觉的生理学基础（一）味蕾的刺激活动（二）味觉阈值分类二、尝味及味感觉机理（一）尝味试验的味扰作用（二）味感觉及舌图三...     

Fate of explosives and their metabolites in bioslurry treatment processes

Microcosm tests simulating bioslurry reactors with 40% soilcontent, containing high concentrations of TNT and/or RDX,and spiked with either [¹⁴C]-TNT or[¹⁴C]-RDX were conducted to investigate the fate ofexplosives and their metabolites in bioslurry treatment processes.RDX is recalcitrant to indigenous microorganisms in soil andactivated sludge under aerobic conditions. However, soilindigenous microorganisms alonewere able to mineralize 15% of RDX to CO₂ underanaerobic condition, and supplementation of municipal anaerobicsludge as an exogenous source of microorganismssignificantly enhanced the RDX mineralization to 60%. RDXmineralizing activity of microorganisms in soil and sludge wassignificantly inhibited by the presence of TNT. TNTmineralization was poor (< 2%) and was not markedlyimproved by the supplement ofaerobic or anaerobic sludge. Partitioning studies of[¹⁴C]-TNT in the microcosmsrevealed that the removal of TNTduring the bioslurry process was due mainly to thetransformation of TNT and irreversiblebinding of TNT metabolites onto soil matrix. In the case ofRDX under anaerobic conditions,a significant portion (35%) of original radioactivity wasalso incorporated into the biomass andbound to the soil matrix.     

Four Ubiquitously Expressed Genes,RD(D6S45)–SKI2W(SKIV2L)–DOM3Z–RP1(D6S60E), Are Present between Complement Component Genes FactorBandC4in the Class III Region of the HLA

The association of the HLA class III region with many diseases motivates the investigation of unidentified genes in the 30-kb segment between complement component genesBfandC4. RD,which codes for a putative RNA binding protein, is 205 bp downstream ofBf. SKI2W(HGMW-approved symbol SKIV2L), a DEVH-box gene probably involved in RNA turnover, is 171 bp downstream ofRD(HGMW-approved symbol D6S45).RP1(HGMW-approved symbol D6S60E) is located 611 bp upstream ofC4.The DNA sequence between humanRDandRP1was determined and the exon–intron structure ofSKI2Welucidated.SKI2Wconsists of 28 exons. The putative RNA helicase domain of Ski2w is encoded by 9 exons. Further analysis of the 2.5-kb intergenic sequence betweenSKI2WandRP1led to the discovery ofDOM3Z.The full-length cDNA sequence ofDOM3Zencodes 396 amino acids with a leucine zipper motif. Dom3z-related proteins are present in simple and complex eukaryotes. InCaenorhabditis elegans,Dom3z-related protein could be involved in the development of germ cells. HumanRD–SKI2WandDOM3Z–RP1are arranged as two head-to-head oriented gene pairs with unmethylated CpG sequences at the common 5′ regulatory region of each gene pair. The ubiquitous expression pattern suggests that these four genes are probably housekeeping genes.     

用SDS．NaClO从重组大肠杆菌中分离聚-β-羟基丁酸酯

聚β羟基丁酸酯（ＰＨＢ）是微生物合成的一种以颗粒状态存在于细胞中的高分子聚合物,由于它具有生物可降解性、生物相容性等特性,在医学上具有独特而广阔的应用前景。从微生物细胞中分离ＰＨＢ的方法有溶剂萃取法［１］、化学试剂法［２４］和酶法［５］。目前工...     

含par位点的重组质粒Psjm3的构建及其稳定性研究

利用自然质粒pSC101par位点的分离稳定性功能,构建了含par位点的质粒pSJM4和pSJM3,通过在同样宿主E.coli HB101中的稳定性比较研究表明,不含par位点的重组质粒pSJ3很不稳定,E.coli G3(pSJ3)在培养到第10代时已开始出现pSJ3的丢失,到培养至50代时则已全部丢失;而含par位点的重组质粒pSJM3则表现得十分稳定,E.coli G3-1(pSJM3)经70代培养,仍无明显的质粒丢失现象,其稳定率保持97%以上。通过对不含par和含par的非重组质粒pUC18和pSJM4的稳定性比较也获得同样的结果。通过对E.coliG3(pSJ3)和E.coli G3-1(pSJM3)的产酶活性比较研究表明,G3-1菌株明显高于G3菌株,说明我们构建的重组质粒pSJM3上的par位点功能不仅没有因外源基因的表达而受影响,而且有利于外源基因的表达。