Detoxifying moniliformin in grains and water

The method to determine moniliformin content was established in our laboratory. The recovery rate is 97 7% while the moniliformin content in the sample is 8 8 mg/g. In comparison with different methods of detoxifying moniliformin in water, the best antidote is chlorinated lime. 1 5 mg active chlorine in chlorinated lime was required to detoxify 1 mg moniliformin. 5% H 2O 2 spray was the best way for detoxifying moniliformin in grains. These two methods are convenient, economic and with no secondary pollution. They can be used for preventing human and livestock from the toxicity of moniliformin.

三维重建在早期非小细胞肺癌胸腔镜下肺段切除术中的应用

目的探讨三维重建技术在早期非小细胞肺癌胸腔镜下肺段切除术中的应用价值。方法回顾性分析因肺部高危结节于2021年1—11月在郑州大学第一附属医院接受胸腔镜肺段切除术的60例患者的临床资料,其中经术前三维重建的患者30例,对照组30例。收集手术时长、术中出血量、术后引流量、引流管拔出时间、术后住院时间及围手术期并发症进行统计分析。结果两组患者的基本资料(性别、年龄、吸烟史、肺功能、肺段切除范围)差异无统计学意义(P>0.05)。三维重建组手术时长[(131.07±27.15)min]短于对照组[(152.43±35.10)min],三维重建组术中出血量[50.00(30.00,50.00)mL]少于对照组[55.00(50.00,72.50)],差异有统计学意义(P<0.05)。两组患者的术后引流量、引流管拔除时间、术后住院时间及围手术期并发症发生率,差异无统计学意义(P>0.05)。结论三维重建技术有助于缩短手术时长和减少术中出血量,可以辅助医生制定精确的个体化手术方案,降低手术难度,使手术更加安全快速地进行。

性别决定区相关高迁移率族盒蛋白4在非小细胞肺癌组织中的表达及临床意义

目的探讨性别决定区相关高迁移率族盒蛋白4(SOX4)在非小细胞肺癌(NSCLC)组织中的表达及临床意义。方法应用荧光定量聚合酶链反应和免疫组化染色测定63例NSCLC患者肿瘤组织及癌旁正常组织中SOX4 mRNA和蛋白表达情况,分析其与临床病理特征之间的关系。结果SOX4 mRNA在NSCLC肿瘤组织和癌旁正常组织中的表达水平分别为1.25±0.72和0.58±0.52,比较差异有统计学意义(t=10.419,P<0.001)。SOX4蛋白在NSCLC肿瘤组织和癌旁正常组织中的高表达率分别为60.3%(38/63)和30.2%(19/63),差异有统计学意义(χ^(2)=11.565,P<0.001)。肿瘤组织中SOX4表达与NSCLC分化程度(χ^(2)=9.839,P=0.007)、临床分期(χ^(2)=10.030,P=0.002)、淋巴结转移(χ^(2)=10.240,P<0.001)有关。结论SOX4在NSCLC肿瘤组织中的高表达,且高表达多见于病情严重患者。

The secretion of lecithinase of Pseudomonas alcaligenes S2 was via type II secretion pathway

Strain S2 is a lecithin (or phosphatidylcholine)- solubilizing bacterium, which was isolated from the rice rhizosphere in rural areas of Beijing, China. On the basis of a polyphasic study involving phenotypic tests, physiological and biochemical tests, 16S rDNA sequence analysis, G+C content determination and DNA-DNA hybridizations analy-sis, strain S2 was identified as Pseudomonas alcaligenes. P. alcaligenes S2 was mutagenized with Tn5 and four mutants showing decreased or increased solubilizing ability of lecithin were isolated based on the halo size around colonies on the solid plate supplemented with egg yolk. To characterize the genes of P. alcaligenes S2 involved in solubilization of lecithin, the EcoR I fragments of the chromosomes from the four mutant strains carrying a single transposon were cloned, and the DNA sequences flanking the Tn5 were determined. The Tn5 insertion sites in the mutants M808, M1329 and M1400, showing decreased solubilizing ability of lecithin, were found to be located in the xcpS, xcpX and xcpW , respectively, whose products XcpS, XcpX and XcpW were the components of type II secretion pathway. Complementation of xcpS, xcpX and xcpW could restore the corresponding mutants M808, M1329 and M1400 to solubilize lecithin. The data suggested that mutation in one of these xcp genes would lead to the absence of mature lecithinase secretion into the extracellular medium. The data also indicated that the secretion of leci-thin-hydrolyzing enzyme of P. alcaligenes was via type II secretion pathway. In the mutant M20 showing increasing lecithin-hydrolyzing activity, the interrupted gene showed 86% identity with chpA of Pseudomonas aeruginosa PAO1, whose product plays an important role in controlling twitch-ing motility of the bacterial cells.

Hydrogen production by draTGB hupL double mutant of Rhodospirillum rubrum under different light conditions

To increase H2 yield of Rhodospirillum rubrum in two-stage hydrogen production process, two deletion mutants were constructed. One is single mutant designated R. rubrum UR801 that deleted hupL gene encoding the large subunit of uptake hy- drogenase, and the other is a double mutant desig- nated R. rubrum UR805 lacked both draTGB encod- ing regulators for the activity of nitrogenase and hupL. Comparing H2 yields of two mutants with R. rubrum UR2 (wild type) and UR472 (ΔdraTGB) under differ- ent light conditions, the results showed that the H2 yield of R. rubrum UR801 under continuous light is the highest (5700 mL of H2 per liter culture), and it is 1.56, 2.24 and 2.32-fold that of R. rubrum UR2, UR472 and UR805, respectively. However, the total H2 yield of R. rubrum UR805 in two-stage hydrogen production process is the highest (4303 mL/L), and it is 1.35, 1.21 and 1.04-fold that of R. rubrum UR2, UR801 and UR472, respectively. Thus, R. rubrum UR805 might be a valuable strain to produce a large amount of hydrogen in two-stage hydrogen produc- tion process.

Cloning and functional analysis of the sequences flanking mini-Tn5 in the magnetosome-deleted mutant NM21 of Magnetospirillum gryphiswaldense MSR-1

A magnetosome-deleted mutant NM21 of Magnetospirillum gryphiswaldense MSR-1 was generated by mini-Tn5 lacZ2 transposon mutagenesis, and a 3073-bp fragment flanking mini-Tn5 lacZ2 in NM21 was cloned by Anchored PCR. Sequencing analysis showed that this fragment involved three putative ORFs; the mini-Tn5 lacZ2 was inserted into ORF1. Functional complementary test indicated that the 3073-bp fragment was required for biosynthesis of magnetosomes in M. gryphiswaldense MSR-1. The majority of proteins, which had homology with the protein encoded by ORF1, were the cation transporter. Transmembrane domain analysis showed that the protein encoded by ORF1 contained four trans-membrane domains. It may be a transmembrane protein. The protein encoded by ORF1 contained two putative conserved domains: COG0053 and PRK09509. The MMT1 and FieF, containing conserved do-mains COG0053 and PRK09509 too, were Fe2+ transporter (cation diffusion facilitator superfamily). It was suggested that the protein encoded by ORF1 might take part in the magnetosomes biosynthesis as Fe2+ transporter.

PAS domain of the deduced Org35 protein mediates the interaction with NifA

NifA in Azospirillum brasilense plays a key role in regulating the synthesis of nitrogenase in response to ammonia and oxygen available. Recently, our laboratory has identified four clones, whose gene prodcuts interact with NifA, from A. brasilense Sp7 genomic libraries by using the yeast two-hybrid sys- tem with NifA as bait. We are interested in clone S35, one of the four clones, because it contains a PAS-domain coding region. The entire open reading frame (ORF) for the PAS domain-containing protein was isolated and designated as org35 here. org35 gene is 2211-bp long and encodes a protein of 736 aa with a predicted molecular weight of about 78.4 kD. The predicted amino acid sequence of org35 has similarity to some two-component sensor kinase/response regulator hybrids of bacteria. Struc- tural analyses showed that Org35 comprises at least three discrete conserved domains: the N-terminal PAS, the central histidine protein kinase (HPK) and the C-terminal response regulator (RR). The PAS domain of the deduced Org35 protein was found to interact directly with NifA, but the central HPK and the C-terminal RR domains of Org35 were not. These results indicated that interaction between NifA and Org35 was mediated by PAS domain.

Functional analysis of hydrogenases and their effects on cell growth and magnetosome synthesis in Magnetospirillum gryphiswaldense

This study addressed the effect of hydrogen metabolism on cell growth and magnetosome synthesis in Magnetospirillum gryphiswaldense strain MSR-1. Two deletion mutants were generated: L206, with single deletion of the hupL gene encoding H2-uptake [NiFe] hydrogenase; and B206, with double deletion of the hyaB gene encoding H2-producing [NiFe] hydrogenase and the hupL gene. The wild-type and mutant strains were compared in terms of hydrogen uptake capability, hydrogen yield, growth rate, and iron uptake, and observed by transmission electron microscopy. Results indicate that HupSL protein is a specific H2-uptake hydrogenase while HyaAB protein is a specific H2-producing hydrogenase. In comparison to wild-type and B206, L206 released a greater quantity of H2 under conditions that induce magnetosomes synthesis, and showed higher rates of growth and iron uptake. M. gryphiswaldense appears to regulate reducing power in vivo, via H2-uptake hydrogenase and H2-producing hy- drogenase, to promote iron absorption and magnetosome synthesis.

Characterization of the flagellar biosynthesis regulatory gene flbD in Azospirillum brasilense

A flagellar gene cluster fragment includingflbD of Azospirillum brasilense was cloned and sequenced. TheflbD mutant strain was found to be nonmotile——losingboth polar and lateral flagella (Fla-Laf-). Motility and fla-gella were regained by complementation with plasmid-borne multicopy flbD, but altered with larger swarming circle and fewer lateral flagella on the semisolid plate. This result indicated that FlbD plays an important role in the regulation of both polar and lateral flagellar biosynthesis in A. brasilense.