Biochemical and physiological characterization of the efrotomycin fermentation

Summary An efrotomycin fermentation was characterized through physical, chemical and biochemical studies. Growth of the actinomycete,Nocardia lactamdurans occurred during the first 50 h of the fermentation cycle at the expense of glucose, protein, and triglycerides. The initiation of efrotomycin biosynthesis was observed when glucose dropped to a low concentration. Upon glucose depletion, cell growth ceased and a switch in the respiratory quotient occurred. Efrotomycin biosynthesis was supported by the utilization of soybean oil and starch. Analysis of triglyceride metabolism showed that no diglycerides or monoglycerides accumulated during the fermentation. The activity of extracellular enzymes (lipase, protease, and amylase) increase during the cell growth phase and decreased significantly after 150 h. The concentrations of DNA, tetrahydro-vitamin K₂ (a membrane component), and free amino acids in the supernatant increased dramatically late in the fermentation cycle (225 h), indicating massive cell lysis. During this same time period, a reduction in cellular respiratory activity and efrotomycin biosynthesis were observed.     

Cloning,characterization and chromosomal localization of the Sus scrofa SLC31A1 gene

Copper is an essential element necessary for normal function of numerous enzymes in all living organisms. Uptake of copper into the cell is thought to occur through the membrane protein, SLC31A1 (CTR1), which has been described in a variety of species including yeast, human and mouse. In this study, we present cloning, gene structure, chromosomal localization and expression pattern of the Sus scrofa SLC31A1 gene, which encodes a 189 amino acid protein. The (SSC) SLC31A1 gene is organized in four exons and spans an approximately 2.3 kb genomic region. We have localized the gene to chromosome 1q28-q2.13 using a somatic cell hybrid panel. This region shows conservation of synteny with human chromosome 9, where the human SLC31A1 (CTR1) gene has been localized. Expression studies suggest that SLC31A1 mRNA is transcribed in all tissues examined.     

Lipid raft redistribution and morphological cell polarization are separable processes providing a basis for hematopoietic stem and progenitor cell migration

Freshly isolated human hematopoietic stem and progenitor cells (HSPCs) are small and round cells which upon cultivation adopt a polarized morphology and redistribute certain cell surface antigens. To functionally dissect this polarization process, we addressed impacts of protein synthesis, HSPC trafficking, cytoskeleton organization or lipid raft integrity on the establishment and maintenance of the cell polarity of human HSPCs. Effects on the morphology, sub-cellular distribution of lipid raft-associated molecular polarization markers (Flotillin-1, Flotillin-2, ICAM-3) and in vitro migration capabilities of treated cells were studied. We could distinguish two levels of cellular polarization, a molecular and a morphological level. Our data suggest that protein synthesis, lipid raft integrity and enzymatic activities of PI3K and aPKC are required to organize the molecular cell polarity. The morphological cell polarization process, however, also depends on actin polymerization and rho-GTPase activities. In summary, our data qualify HSPC polarization processes as new pharmaceutical target to interfere with migratory and with homing capabilities of HSPCs.     

Exclusion of the C/D box snoRNA gene cluster HBII-52 from a major role in Prader–Willi syndrome

Prader–Willi syndrome (PWS) and Angelman syndrome (AS) are distinct neurogenetic disorders caused by the loss of function of imprinted genes in 15q11–q13. The maternally expressed UBE3A gene is affected in AS. Four protein-encoding genes (MKRN3, MAGEL2, NDN and SNURF-SNRPN) and several small nucleolar (sno) RNA genes (HBII-13, HBII-436, HBII-85, HBII-438A, HBII-438B and HBII-52) are expressed from the paternal chromosome only but their contribution to PWS is unclear. To examine the role of the HBII-52 snoRNA genes, we have reinvestigated an AS family with a submicroscopic deletion spanning UBE3A and flanking sequences. By fine mapping of the centromeric deletion breakpoint in this family, we have found that the deletion affects all of the 47 HBII-52 genes. Since the complete loss of the HBII-52 genes in family members who carry the deletion on their paternal chromosome is not associated with an obvious clinical phenotype, we conclude that HBII-52 snoRNA genes do not play a major role in PWS. However, we cannot exclude the possibility that the loss of HBII-52 has a phenotypic effect when accompanied by the loss of function of other genes in 15q11–q13.Electronic Database Information: accession numbers and URLs for data presented herein are as follows: for PAR-4 (accession number AF019617), deletion junction fragment (L15422): GenBank, ; for Angelman syndrome [MIM105830]: Online Mendelian Inheritance in Man (OMIM),     

The evaluation of mixtures of yeast and potato extracts in growth media for biomass production of lactic cultures

The effectiveness of yeast extracts (YE) and potato extracts (PE) to promote growth of seven lactic cultures was evaluated by automated spectrophotometry (AS). Two aspects of the growth curve were analysed: (1) maximum biomass obtained (using ODmax) and (2) highest specific growth rate mu(max)) Eleven lots from the same PE-manufacturing process were examined for lot-to-lot variability. The ODmax values of three of the seven strains were significantly affected by lot source, but mu(max) was not significantly affected. The growth of bacteria was systematically lower in base medium containing 100% PE than in base medium containing 100% YE for both ODmax or mu(max) data, which could be related to the lower content in nitrogen-based compounds in PE. In AS assays, highest OD values for Lactobacillus casei EQ28, Lactobacillus rhamnosus R-011, Lactobacillus plantarum EQ12, and Streptococcus thermophilus R-083 were obtained with a mixture of PE and YE. Fermentations (2 L) were also carried out to determine the accuracy of AS to predict biomass levels obtained under fermentation trials. In these fermentations, replacement of 50% YE with PE was shown to enable good growth of S. thermophilus. With L. rhamnosus R-011, a high correlation (R2 = 0.95) was found between ODmax data obtained in the AS assays and that of the 2-L bioreactor when the same growth medium was used for both series of fermentations. However, AS was not as efficient when industrial media were used for the bioreactor assays. The relationship was still good for ODmax between AS data and that of the bioreactor data with L. rhamnosus R-011 in industrial LBS medium (R2 = 0.87), but was very poor with the S. thermophilus R-083 on Rosell #43 industrial medium (R2 = 0.33). Since PE cost 40% less than YE, there are strong economic advantages in considering such a partial replacement of YE by PE.     

利用分子量阵列平台进行特定序列甲基化分析的方法探讨

目的：探讨利用分子量阵列平台进行特定序列甲基化分析的方法。方法：通过对不同扩增条件和扩增效率及不同条件处理的质谱分析比较了MassArray平台进行甲基化分析的特点。结果：本研究通过与重亚硫酸盐测序结果比较证实,MassArray分子量阵列技术平台能够反映甲基化修饰的真实水平;通过不同条件下PCR扩增效率与甲基化分析的结果,发现扩增效率是制约MassArray分子量阵列技术平台甲基化分析的关键因素,而产物的放置时间和不同的处理没有明显影响甲基化分析。结论：Mas-sArray甲基化分析平台是高效快速检测甲基化修饰的平台,在使用过程中应该根据实际的实验条件,进行合理的质控。     

红籽瓜数量性状分析软件的设计与实现

主要介绍了如何使用面向对象技术对红籽瓜数量性状分析软件的设计,阐述了软件的设计过程,代码的编写。实现了对红籽瓜数量性状的分析。