布拉酵母联合小剂量红霉素对功能性消化不良患儿血清胃动素及胃泌素的影响

目的研究布拉酵母联合小剂量红霉素对功能性消化不良患儿血清胃动素、胃泌素的影响。方法以某医院2017年8月—2018年10月收治的90例功能性消化不良患儿为研究对象,采用随机数字法将所有患儿分为对照组(n=45)、观察组(n=45)。对照组应用小剂量红霉素对患儿进行治疗,观察组在小剂量红霉素的基础上联合布拉酵母治疗。结果观察组恶心、呕吐、嗳气、腹胀及疼痛评分[(7.68±1.78)分、(6.42±0.92)分、(8.21±1.25)分、(8.34±1.33)分、(7.24±1.63)分]均低于对照组[(10.34±1.09)分、(9.42±1.18)分、(12.71±1.43)分、(13.70±1.36)分、(15.39±1.56)分],差异有统计学意义(P<0.05);观察组治疗后血清胃动素为(281.16±45.81)ng/L、胃泌素为(182.65±16.81)ng/L,高于对照组,总有效率(97.78%)高于对照组,差异均有统计学意义(P<0.05)。结论布拉酵母联合小剂量红霉素对功能性消化不良患儿治愈率显著,与其提高患儿胃动素、胃泌素的水平相关。     

Agilent 2100 Bioanalyzer在基因差异表达研究中的应用

目的观察Agilent 2100 Bioanalyzer 芯片分析系统(以下简称Bioanalyzer)在基因差异表达研究中的应用。方法应用限制性显示技术分别从正常和热休克处理后的酿酒酵母细胞中分离出cDNA片段,然后再用Bioanalyzer和传统的琼脂糖凝胶电泳技术对RD-PCR产物进行检测分析。结果Bioanalyzer能更快速、敏感地分离和显示差异表达的基因片段,并且通过对差异片段进行定量比较,发现了数个表达有明显差异的基因片段。结论Bioanalyzer在基因差异表达研究中具有重要的应用价值。     

Failure to detect an antimutator phenotype following disruption of the Saccharomyces cerevisiae DDR48 gene

The antimutator phenotype, reportedly conferred by disruption of the Saccharomyces cerevisiae DDR48 gene, was suggested to affect only a specific spontaneous mutational pathway. We attempted to identify the types of mutation that are DDR48-dependent by determining the specificity of the ddr48 antimutator. However, disruption of DDR48 did not decrease the rates of spontaneous forward mutation in a plasmid-borne copy of the yeast SUP4-o gene, the reversion or suppression of the lys2–1 allele, or forward mutation at the CAN1 locus. Interestingly, the latter gene had been reported previously to be subject to the antimutator effect. DNA sequence analysis of spontaneous SUP4-o mutations arising in DDR48 and ddr48 backgrounds provided no evidence for a reduction in the rates of individual mutational classes. Thus, we were unable to verify that disruption of DDR48 causes an antimutator phenotype.     

Polymeric genes MEL8, MEL9 and MEL10 — new members of α-galactosidase gene family in Saccharomyces cerevisiae

Summary We used a combination of genetic hybridization analysis and electrokaryotyping with radioactively labelled MEL1 gene probe hybridization to isolate and identify seven polymeric genes for the fermentation of melibiose in strain CBS 5378 of Saccharomyces cerevisiae (syn. norbensis). Four of the MEL genes, i.e. MEL3, MEL4, MEL6 and MEL7, were allelic to those found in S. cerevisiae strain CBS 4411 (syn. S. oleaginosus) whereas three genes, i.e. MEL8, MEL9 and MEL10 occupied new loci. Electrokaryotyping showed that all seven MEL genes in CBS 5378 were located on different chromosomes. The new MEL8, MEL9 and MEL10 genes were found on chromosomes XV, X/XIV and XII, respectively.     

啤酒酵母在工业贮存期间的变化对生物合成1，6－二磷酸果糖的影响

随着工业贮存期的延长，啤酒酵母细胞的存活率及对葡萄糖连续磷酸化的速率迅速下降，１，６－二磷酸果糖在发酵液中的浓度由贮存前的７５ｇ／Ｌ降至贮存２个星期时的３０ｇ／Ｌ。     

Self-splicing activity of the mitochondrial group-I introns from Aspergillus nidulans and related introns from other species

The mitochondrial genome of Aspergillus nidulans contains several group-I introns. Each one has been assayed for its ability to self-splice in vitro in the absence of proteins. The intron from the apocytochrome b gene is unusual among subgroup IB4 introns in being able to self-splice, unlike a similar intron from Saccharomyces cerevisiae. The first intron in the cytochrome oxidase subunit-1 gene self-splices but only correctly completes the first step of splicing; cryptic 3′ splice-sites are recognized instead and these are also used at a low frequency in vivo. The highly homologous intron from Podospora anserina completes both steps in vitro. The remaining introns do not self-splice. The correlation between subgroup category, the likely presence of specific tertiary interactions, and self-splicing activity is discussed. Received: 16 May / 25 August 1997     

A mutant allele of the SUP45 (SAL4) gene of Saccharomyces cerevisiae shows temperature-dependent allosuppressor and omnipotent suppressor phenotypes

Using a plasmid-based termination-read-through assay, the sal4-2 conditional-lethal (temperature-sensitive) allele of the SUP45 (SAL4) gene was shown to enhance the efficiency of the weak ochre suppressor tRNA SUQ5 some 10-fold at 30°C. Additionally, this allele increased the suppressor efficiency of SRM2-2, a weak tRNA^Gln ochre suppressor, indicating that the allosuppressor phenotype is not SUQ5-specific. A sup ⁺ sal4-2 strain also showed a temperature-dependent omnipotent suppressor phenotype, enhancing readthrough of all three termination codons. Combining the sal4-2 allele with an efficient tRNA nonsense suppressor (SUP4) increased the temperature-sensitivity of that strain, indicating that enhanced nonsense suppressor levels contribute to the conditional-lethality conferred by the sal4-2 allele. However, UGA suppression levels in a sup ⁺ sal4-2 strain following a shift to the non-permissive temperature reached a maximum significantly below that exhibited by a non-temperature sensitive SUP4 suppressor strain. Enhanced nonsense suppression may not therefore be the primary cause of the conditional-lethality of this allele. These data indicate a role for Sup45p in translation termination, and possibly in an additional, as yet unidentified, cellular process.     

Characterization of a novel α-amylase from Lipomyces kononenkoae and expression of its gene (LKA1) in Saccharomyces cerevisiae

A highly active -amylase (76 250 Da) secreted by the raw starch-degrading yeast Lipomyces kononenkoae strain IGC4052B was purified and characterized. Using high performance liquid chromatography (HPLC), end-product analysis indicated that the L. kononenkoae -amylase acted by endo-hydrolysis on glucose polymers containing -1,4 and -1,6 bonds, producing mainly maltose, maltotriose and maltotetraose. The following NH₂-terminal amino acids were determined for the purified enzyme: Asp-Cys-Thr-Thr-Val-Thr-Val-Leu-Ser-Ser-Pro-Glu-Ser-Val-Thr-Gly. The L. kononenkoae -amylase-encoding gene (LKA1), previously cloned as a cDNA fragment, was expressed in Saccharomyces cerevisiae under the control of the PGK1 promoter. The native signal sequence efficiently directed the secretion of the glycosylated protein in S. cerevisiae. De-glycosylation of the enzyme indicated that post-translational glycosylation is different in S. cerevisiae from that in L. kononenkoae. Zymogram analysis indicated that glycosylation of the protein in S. cerevisiae had a negative effect on enzyme activity. Southern-blot analysis revealed that there is only a single LKA1 gene present in the genome of L. kononenkoae.