E.coli

摘要： Meat constitutes the main source of protein and occupies an important place in our diet. Indeed, the production of poultry and beef has increased. However, the hygienic quality of meat is not always guaranteed. Microorganisms such as Escherichia coli can be found in meat and can cause various infections including diarrhea, dysentery, food poisoning, gastroenteritis or typhoid fever. Thus, the present study was designed to characterize Escherichia coli (E. coli) from beef and chicken consumed in restaurants in Yaoundé Cameroon. A total of 105 meat samples (60 beef and 45 chickens) were subjected to microbial culture for E. coli isolation and further confirmed by Polymerase Chain Reaction (PCR) using primers EC-F and EC-R that are specific to E. coli 16S rRNA gene. The supplier source, storage, and transport conditions were taken into consideration during sample analysis and data processing. This study revealed that 77/105 samples (73.33%) were positive for E. coli following microbial culture and 35 (33.33%) were positive for E. coli following molecular examination. A statistically significant difference was observed when PCR and microbial culture were used to assess for E. coli in beef and a non-statistically significant difference was observed in the case of chicken meat. Also, a statistically significant difference was noticed with the different transport conditions, but this wasn’t the case with the supplier source as well as the storage conditions where a non-statistically significant difference was seen. This study revealed that PCR-based methods are fast and reliable in the identification and characterization of Escherichia coli in meats (beef and chicken) as well as in assessing the prevalence of pathogenic E. coli, in Cameroon.

摘要： The research question being studied in this paper is how do different types of bacteria as food (Pseudomonas fluorescens and Bacillus megaterium) affect the lifespan of Caenorhabditis elegans in dpy-11 mutant-type and wild-type? P. fluorescens and B. megaterium will be the two pathogens that will be tested on two different types of C. elegans: mutant-type dpy-11 and wild-type. From the analysis of primary articles studying these pathogens, it can be concluded that P. fluorescens and B. megaterium are decent contenders for allowing C. elegans to grow and possibly extend the lifespan of it. P. fluorescens will allow the lifespan of the two types of nematodes to be longer. Additionally, the mu-tant-type dpy-11 of C. elegans will have a much longer lifespan, even double, compared to that of the wild-type. The results showed P. fluorescens had a longer lifespan than B. megaterium but not as long as C. elegans’ main food source, E. coli. C. elegans mutant dpy-11 had a longer lifespan than the wild-type. Furthermore, there were no C. elegans present in the B. megaterium wild-type plates.

摘要： Onion(Allium cepa L.)is a common biennial herb,and contains allicin compounds which can kill harmful microorganism.The antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations on Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were studied.There were differences among the antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations.What was more,the antibacterial effects of raw onion juice were better than those of the mature one.The antibacterial effects of high concentration onion juice were better than those of the low one.The content of the total flavonoids in raw purple onion was higher than that in mature onion,and reached extremely significant levels in 50%,75%and 100%,respectively.Through comparison,it was found that onion juice of purple-skinned had the best suppression effects on S.aureus(gram-positive bacterium)and E.coli(gram-negative bacterium),and gram-positive bacterium had better suppression effects than gram-negative bacterium.It wound provide the basis about bioactive function and antibacterial drugs.

摘要： E.coli and Listeria monocytogenes(or L.monocytogenes)are bacteria affecting fresh produce that is harmful for health of humans and animals.If these bacteria are present in surface waterbody(e.g.,irrigation canals),they will impair irrigation water quality and threaten produce safety.This paper studied the resuspension of E.coli and Listeria from bed sediment into irrigation water through several sets of laboratory experiments in an open channel flume.We studied three types of sediments using several flow rates in different velocities and shear stress.Bacteria's concentration in water increases with the bed shear stress.Two empirical relations were derived to correlate the concentration of E.coli and L.monocytogenes with the dimensionless bed shear stress.The experimental data favorably verified the relationships for sandy loam,loamy sand,and loam.The results showed that both bacteria could entrain from sand more efficiently compared to other sediments(i.e.,sandy loam or loam).These relationships can be applied to water quality models for simulating E.coli and L.monocytogenes transport in irrigation canals for better managing irrigation water quality.

摘要： 为了探究大肠杆菌(E.coli)对藏羊子宫内膜上皮细胞(EECs)相关凋亡因子表达的影响,采用酶消化法培养EECs,用不同感染复数(MOI)进行E.coli感染试验,通过流式细胞术(Flow CytoMetry,FCM)检测EECs的凋亡率,用实时荧光定量PCR(qRT-PCR)及免疫印迹法(Western Blot)检测Caspase-3、Bcl-2和Bax等凋亡因子RNA和蛋白的表达水平.结果显示,在培养液中加入50 ng/mL表皮生长因子(EGF)能成功培养出EECs,其纯度达到98％以上;E.coli感染试验中,当MOI为1 ∶ 1时,Caspase-3和Bax在EECs的表达量与对照组相比变化不明显,而Bcl-2的表达量显著升高;当MOI为20 ∶ 1时,Bax的表达量显著升高;当MOI为50 ∶ 1时,Caspase-3的表达量显著升高,而Bcl-2的表达量与对照组相比变化不明显.结果表明,酶消化法可成功培养EECs;不同MOI的E.coli感染后,EECs中Caspase-3、Bcl-2和Bax等凋亡因子的表达量较空白组有不同程度的升高,这些凋亡因子可作为识别子宫内膜炎病理变化程度的指标.

摘要： 为了探究大肠杆菌(Escherichia coli)对藏羊子宫内膜上皮细胞(EECs)相关炎性因子表达的影响,本研究采用组织块贴壁法和酶消化法培养藏羊EECs;用不同感染复数(MOI)进行E.coli感染试验,通过实时荧光定量PCR(qRT-PCR)及酶联免疫(ELISA)技术,分析白细胞介素1β(IL-1β)、白细胞介素6(IL-6)、白细胞介素8(IL-8)和肿瘤坏死因子α(TNF-α)等炎性因子的RNA和蛋白表达水平。结果表明,培养液中加入50 ng·mL^(-1)表皮生长因子(EGF)能成功培养出藏羊EECs,纯度达到98%以上;E.coli感染试验中,当MOI为1∶1时,IL-1β、IL-6和IL-8基因和蛋白的表达量与对照组相比差异不显著,而TNF-α表达量显著升高(P0.05)。结果表明,酶消化法可成功培养藏羊EECs;不同MOI E.coli感染后,藏羊EECs中IL-1β、IL-6、IL-8和TNF-α等炎性因子的表达量较对照组均显著升高(P<0.05),它们可作为识别子宫内膜炎病理变化程度的指标。本研究结果为预防子宫内膜炎、提高藏羊的生产性能以及生态养殖提供了理论依据。

摘要： 美国FDA于2021年6月30日批准Jazz制药公司(Jazz Pharmaceuticals)的Rylaze[asparaginase erwinia chrysanthemi(recombinant)-rywn,重组菊欧氏杆菌天冬酰胺酶-rywn]作为化疗药物用于治疗成人及儿童急性淋巴细胞白血病及淋巴母细胞淋巴瘤,适用于对大肠埃希菌产天冬酰胺酶类药物(E.coli-derived asparagi‐nase,一种最常用的白血病化疗药物)过敏的患者。此前FDA曾经批准过一种同类型药物,但多年来一直处于全球紧缺状态。

摘要： Microuidic channels play a vital role in separation of analytes of interest such as bacteria and platelet cells,etc.,in various biochemical diagnosis procedures including urinary tract infections(UTI)and bloodstream infections.This paper presents the multi physics computational model specifically designed to study the effects of design parameters of a microuidics channel for the separation of Escherichia coli(E.coli)from various blood constituents including red blood cells(RBC)and platelets.A standard two inlet and a two outlet microchannel of length 805µm with a channel width of 40µm is simulated.The effect of electrode potentials and the effect of electrode placement along the channel length and also the levitation of electrodes from the channel wall are studied to optimize the selective particle separation throughput.Simulated results show the efcient separation of E-coli with a mean diameter 0.68µm is achieved at low voltages(less than 20 V)when electrodes placed near to the micro channel and also noticed that the applied electric potential is inversely proportional to the number of electrodes placed along the microuidic channel.The computer aided multi physics simulations with multiple governing parameters could be advantage in design optimization of microuidics channels and support precise bioparticle separation for better diagnosis.

摘要： Escherichia coli has become one of the most important causes of calf diarrhea.The aim of this study is to determine the patterns of antimicrobial resistance of E.coli isolates from six cattle farms and to identify prominent resistance genes and virulence genes among the strains isolated from the diarrhea of calves.Antimicrobial susceptibility tests were performed using the disk diffusion method,and PCR was used to detect resistance and virulence genes.The prevalence of multidrug resistant(MDR)E.coli was 77.8%in dairy cattle and 63.6%in beef cattle.There were high resistance rates to penicillin(100%,100%)and ampicillin(96.3%,86.4%)in E.coli from dairy cattle and beef cattle.Interestingly,resistance rate to antimicrobials and distribution of resistance genes in£coli isolated from dairy cattle were higher than those in beef cattle.Further analysis showed that the most prevalent resistance genes were blojm and oodAl in dairy cattle and beef cattle,respectively.Moreover,seven diarrheagenic virulence genes(irp2,fyuA,Stx1,eoeA,F41,K99 and STa)were present in the isolates from dairy cattle,with a prevalence ranging from 3.7%to 22.22%.Six diarrheagenic virulence genes(irp2,fyuA,Stx1,eoeA,hylA and F41)were identified in the isolates from beef cattle,with a prevalence ranging from 2.27%to 63.64%.Our results provide important evidence for better exploring their interaction mechanism.Further studies are also needed to understand the origin and transmission route of£coli in cattle to reduce its prevalence.

摘要： 本文从生物化学角度通过生理现象和代谢功能参数的变化给出某些实验依据，以生化实验结果验证水是否具有结构与功能效应，再对控制和影响水分子簇微观结构的物理化学条件进行尝试性探索。生化实验表明冰化后的水分子簇表现了良好的生物活性。经过一定条件下冰化处理过的水体具有动态的液态晶格结构，并具有结构记忆功能，而这种结构记忆功能是温度和时间的函数。

摘要： 本文从生物化学角度通过生理现象和代谢功能参数的变化给出某些实验依据，以生化实验结果验证水是否具有结构与功能效应，再对控制和影响水分子簇微观结构的物理化学条件进行尝试性探索。生化实验表明冰化后的水分子簇表现了良好的生物活性。经过一定条件下冰化处理过的水体具有动态的液态晶格结构，并具有结构记忆功能，而这种结构记忆功能是温度和时间的函数。

摘要： 本文从生物化学角度通过生理现象和代谢功能参数的变化给出某些实验依据，以生化实验结果验证水是否具有结构与功能效应，再对控制和影响水分子簇微观结构的物理化学条件进行尝试性探索。生化实验表明冰化后的水分子簇表现了良好的生物活性。经过一定条件下冰化处理过的水体具有动态的液态晶格结构，并具有结构记忆功能，而这种结构记忆功能是温度和时间的函数。

摘要： 本文从生物化学角度通过生理现象和代谢功能参数的变化给出某些实验依据，以生化实验结果验证水是否具有结构与功能效应，再对控制和影响水分子簇微观结构的物理化学条件进行尝试性探索。生化实验表明冰化后的水分子簇表现了良好的生物活性。经过一定条件下冰化处理过的水体具有动态的液态晶格结构，并具有结构记忆功能，而这种结构记忆功能是温度和时间的函数。

摘要： 本文从生物化学角度通过生理现象和代谢功能参数的变化给出某些实验依据，以生化实验结果验证水是否具有结构与功能效应，再对控制和影响水分子簇微观结构的物理化学条件进行尝试性探索。生化实验表明冰化后的水分子簇表现了良好的生物活性。经过一定条件下冰化处理过的水体具有动态的液态晶格结构，并具有结构记忆功能，而这种结构记忆功能是温度和时间的函数。

摘要： 本文从生物化学角度通过生理现象和代谢功能参数的变化给出某些实验依据，以生化实验结果验证水是否具有结构与功能效应，再对控制和影响水分子簇微观结构的物理化学条件进行尝试性探索。生化实验表明冰化后的水分子簇表现了良好的生物活性。经过一定条件下冰化处理过的水体具有动态的液态晶格结构，并具有结构记忆功能，而这种结构记忆功能是温度和时间的函数。

摘要： 本发明公开了一种嘌呤核苷磷酸化酶基因敲除的大肠杆菌Ecoli-SL26的构建方法，本方法采用Red/ET系统同源重组敲除嘌呤核苷磷酸化酶基因，在四环素（Tet）和卡那霉素（Kam）双重抗性下筛选到了嘌呤核苷磷酸化酶基因成功敲除的菌株Eocli-SL26。本发明成功沉默了肌苷水解为次黄嘌呤的途径，提高了酶催化的转化率和5`-磷酸化肌苷的纯度，降低了肌苷的损耗和生产成本，有利于后续5`-磷酸化肌苷的提取和残余肌苷的套用，该发明对酶催化肌苷5`-磷酸化的产业化进程具有重要意义。