EFFECT OF PYRENE ON THE PROLIFERATION AND DIFFERENTIATION OF OSTEOBLAST CELLS

芘(Py)是一种典型的多环芳烃，含有四个苯环，主要来源于有机物的不完全燃烧， 广泛存在于饮用水、食物以及空气中。尽管研究表明大多数多环芳烃有毒性和致癌性，但是有关芘的毒理学数据还很有限。本实验的目的是了解芘对MC3T3-E1细胞系的增殖和分化的影响。实验中用不同浓度的芘对MC3T3-E1细胞进行暴污培养，并根据实验需要暴污培养6或21天。细胞形态观察显示小鼠成骨细胞正常培养下在贴壁后伸展形成三角形、梭形及多边形几种主要形状，而芘的暴污没有对细胞形态造成明显变化。同时还观察检测了钙化结节的形成情况，各组间的变化无显著性差异。碱性磷酸酶的活性随着芘的浓度的增加成下降趋势，存在剂量效应。实验结果说...Pyrene is a group of halogenated aromatic hydrocarbons, synthetic chemicals which do not occur naturally in the environment. Pyrene (Py), one kind of typical PAHs consisting of four fused benzene rings, resulting in a flat aromatic system. Pure pyrene is a colorless solid but when it is recrystallized from toluene or it is impure the substance becomes pale yellow. This colorless solid is the smal...学位：理学硕士院系专业：生命科学学院生物化学与生物技术系_生物化学与分子生物学学号：2162008115375

Molecular characterization of Brucella spp. from seropositive herds of cattle farmed at the wildlife-livestock-human interface in Rwanda

DATA AVAILABILITY STATEMENT : The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author.Seroprevalence studies showed that brucellosis is prevalent in cattle in Rwanda with no recent study on the characterization of Brucella spp. Therefore, this study aimed to characterize Brucella spp. in seropositive herds of cattle farmed at the wildlife–livestock–human interface. Whole blood samples (n = 118), milk (n = 41), and vaginal swabs (n = 51) were collected from 64 seropositive herds. All samples (n = 210) were inoculated onto modified Centro de Investigacion y Tecnologia Agroalimentaria (CITA) selective medium. Cultures were analyzed to detect Brucella spp. using 16S−23S ribosomal DNA interspacer region (ITS) PCR, the Brucella cultures were speciated using AMOS and Bruce-ladder PCR assays. Brucella spp. were detected in 16.7% (35/210) of the samples established from the samples using ITS-PCR. The AMOS PCR assay identified mixed Brucella abortus and B. melitensis (n = 6), B. abortus (n = 7), and B. melitensis (n = 1) from cultures from blood samples; mixed B. abortus and B. melitensis (n = 1) and B. abortus (n = 4) from cultures from milk samples; mixed B. abortus and B. melitensis (n = 6), B. abortus (n = 8), and B. melitensis (n = 1) from cultures from vaginal swabs. Bruce-ladder PCR assay confirmed B. abortus and B. melitensis cultures. The isolation of Brucella spp. was significantly associated with districts, with the Nyagatare district having more isolates than other districts (p=0.01). This study identified single ormixed B. abortus and B. melitensis infections in cattle samples in Rwanda, which emphasizes the need to improve brucellosis control at the wildlife–livestock– human interface and raise the awareness of cattle keepers, abattoir workers, laboratory personnel, and consumers of cattle products.The Belgian Directorate- General for Development Cooperation, through its Framework Agreement with the Institute of Tropical Medicine.https://www.frontiersin.org/journals/veterinary-scienceam2023Veterinary Tropical Disease

Integration of GC-MS in identification of possible final metabolites from phytase production in Pichia Pastoris based on sorbitol induction optimization

The isolation of phytase using Pichia Pastoris under methanol/sorbitol co-feeding induction technique was investigated. The biological activity of extracellular phytase after optimization with co-substrates induction in 4 liters fermentor (NBS) increased to 13250 U/ml. This led to a 509 fold increases in comparison to the other type of phytase. This effect was studied via induction with sorbitol/methanol in fermentation by Pichia Pastoris GS115 (Mut+) at 20 °C. The interference of by products; methylal, hexamine and (S)-(+)-1,2-propanediol with release of phytase in Pichia Pastoris under methanol induction were detected and cannot be repressed by methanol induction alone. The TLC was used for glycerin analysis under methanol/sorbitol induction and the results were lesser compare to that obtained during phytase production under methanol induction alone. This work showed the higher expression of heterologous proteins and by fed batch fermentation; the expression identified an advantage of producing a significant activity of phytase. Practical applications Plant derived products including sorbitol have been used as alternative medicines for the therapeutic treatment of various diseases, food supplements and could be used in many manufacturing processes. It serves as a culture media for bacteria, and helps to distinguish the pathogenic E. coli O157:H7 from its most other strains. Cells growing on methanol require high oxygen consumption. Sorbitol was used as an alternative cheap co-feeding for the production of proteins and is a non-repressing carbon source for AOX1 promoter with no effect on the level of r-protein at its induction phase. This report describes the isolation of phytase using Pichia Pastoris under methanol/sorbitol co-feeding induction techniques, and sorbitol showed to be a promising co-substrate, as it could enhance both cell growth and targeted protein productivity. This co-feeding and fed-batch induction technique was used for recombinant phytase production in a small and large scale production and the metabolites were analyzed