Proteomics integrated with Escherichia coli vector-based vaccines and antigen microarrays reveals the immunogenicity of a surface sialidase-like protein of Propionibacterium acnes

Proteomics is a powerful tool for the identification of proteins, which provides a basis for rational vaccine design. However, it is still a highly technical and time‐consuming task to examine a protein's immunogenicity utilizing traditional approaches. Here, we present a platform for effectively evaluating protein immunogenicity and antibody detection. A tetanus toxin C fragment (Tet‐c) was used as a representative antigen to establish this platform. A cell wall‐anchoring sialidase‐like protein (SLP) of Propionibacterium acnes was utilized to assess the efficacy of this platform. We constructed an Escherichia coli vector‐based vaccine by overexpressing Tet‐c or SLP in E. coli and utilized an intact particle of E. coli itself as a vaccine (E. coli Tet‐c or SLP vector). After ultraviolet (UV) irradiation, the E. coli vector‐based vaccines were administered intranasally into imprinting control region mice without adding exogenous adjuvants. For antibody detection, we fabricated antigen microarrays by printing with purified recombinant proteins including Tet‐c and SLP. Our results demonstrated that detectable antibodies were elicited in mice 6 weeks after intranasal administration of UV‐irradiated E. coli vector‐based vaccines. The antibody production of Tet‐c and SLP was significantly elevated after boosting. Notably, the platform with main benefits of using E. coli itself as a vaccine carrier provides a critical template for applied proteomics aimed at screening novel vaccine targets. In addition, the novel immunogenic SLP potentially serves as an antigen candidate for the development of vaccines targeting P. acnes‐associated diseases.     

Effect of Yeast Extracts Containing Propionic Acid on Bread Dough Fermentation and Bread Properties

ABSTRACT: Three commercial yeast extracts (Oxoid, Champlain, Lallemand) fermented with immobilized cells of Propionibacterium freudenreichii were added in broths and bread formulations, and their effect on growth and gas production by bakers yeast was determined. Appearance and preservation of the breads were examined. There was significantly more gas produced by the yeast when fermented yeast extracts were added to the dough. In broths, the initial growth rate was slower with media containing fermented yeast extract when compared to their unfermented equivalents. Loaves formulated with propionic acid of the fermented yeast extract contained less ethanol. Paired t-tests showed that breads formulated with fermented yeast extract were protected for a longer period against mold than those that contained non-fermented yeast extract.     

产共轭亚油酸丙酸菌的筛选及转化条件初探

通过富集培养、梯度密度稀释和液体培养发酵,采用紫外分光光度法测定共轭亚油酸(CLA),从市售奶酪中筛选获得1株转化生成CLA能力相对较高的菌株P9:考察了菌体接种量、亚油酸(LA)的添加量、反应温度、反应体系pH值以及乳化剂种类等因素对菌株P9 CLA生成量的影响.通过对菌株P9的菌落和形态特征、产丙酸特性及生理生化特性分析,初步鉴定该菌株为费氏丙酸杆菌(Propionibacterium frudenreichii).研究结果显示,菌株P9在菌体接种量10%(v/v),LA添加量0.75mg/mL,pH值为6.8,反应温度30℃,Tween-80作为乳化剂的条件下,CLA生成量为63.371μg/mL,亚油酸转化率为8.45%,表现出较好的产共轭亚油酸能力.     

In vitro antimicrobial and anti-inflammatory effects of herbs against Propionibacterium acnes

Propionibacterium acnes play an important role in the pathogenesis of acne by inducing certain inflammatory mediators and comedogenesis. The objective of this study was to evaluate the antimicrobial and anti-inflammatory effects of herbal extracts against P. acnes. Among the ten tested herbs, methanolic extracts of rose (Rosa damascene), duzhong (Eucommia ulmoides Oliv.), and yerba mate (Ilex paraguariensis) were found to inhibit the growth of P. acnes with respective minimum inhibitory concentrations of 2, 0.5, and 1 mg/ml. In addition, duzhong and yerba mate extracts reduced the secretion of pro-inflammatory cytokines such as tumour necrosis factor-α, interleukin (IL)-8, and IL-1β by human monocytic THP-1 cells pretreated with heat-killed P. acnes at a concentration of 0.1 mg/ml. Our results suggested that duzhong and yerba mate extracts possess both antimicrobial and anti-inflammatory effects against P. acnes and can possibly be used as therapeutic agents for acne.     

Direct Extraction of Propionic Acid from Propionibacterium acidipropionici Broths with Tri‐n‐octylamine

The direct reactive extraction of propionic acid from Propionibacterium acidipropionici broths with solutions of tri‐n‐octylamine in dichloromethane, n‐butyl acetate or n‐heptane underlined the strong negative influence of the cells, due to the blockage of the interface by their adsorption. The magnitude of this effect <#>depends on the affinity of the cells for the organic phase, which is more important for n‐heptane, but only at biomass concentrations below 18 g L^–1 d.w. (dry weight). Moreover, the interfacial mass transfer of the acid is also controlled by the solvent polarity, and is accelerated from n‐heptane to dichloromethane and by the addition to the organic phase of 1‐octanol as a phase modifier. The influences of the biomass concentration, the rotation speed and the solvent dielectric constant were included in a mathematical model describing the solute mass flow from the aqueous to the organic phase.     

Importance of Kupffer Cells in the Development of Acute Liver Injuries in Mice

Kupffer cells reside within the liver sinusoid and serve as gatekeepers. They produce pro- and anti-inflammatory cytokines and other biologically important molecules upon the engagement of pattern recognition receptors such as Toll-like receptors. Kupffer cell-ablated mice established by in vivo treatment with clodronate liposomes have revealed many important features of Kupffer cells. In this paper, we review the importance of Kupffer cells in murine acute liver injuries and focus on the following two models: lipopolysaccharide (LPS)-induced liver injury, which is induced by priming with Propionibacterium acnes and subsequent challenge with LPS, and hypercoagulability-mediated acute liver failure such as that in concanavalin A (Con A)-induced hepatitis. Kupffer cells are required for LPS sensitization induced by P. acnes and are a major cellular source of interleukin-18, which induces acute liver injury following LPS challenge. Kupffer cells contribute to Con A-induced acute liver failure by initiating pathogenic, intrasinusoidal thrombosis in collaboration with sinusoidal endothelial cells. The mechanisms underlying these models may shed light on human liver injuries induced by various etiologies such as viral infection and/or abnormal metabolism.     

Production of 5-aminolevulinic acid by Propionibacterium acidipropionici TISTR442

Propionibacterium acidipropionici TISTR442 produced the highest amount of 5-aminolevulinic acid (ALA) when cultivated in medium supplemented with glycine at 18g/l. ALA production correlated with ALA synthase activity, whereas ALA dehydratase activity was maintained at a low level. ALA yield reached 405mg/l after prolonged cultivation for 1 month.     

响应面法优化产酸丙酸杆菌丙酸发酵条件的研究

采用Box-Behnken设计和响应面分析法(Response surface methodology,RSM),以产酸丙酸杆菌发酵甘油产丙酸的3个关键因素(培养温度、pH和接种量)为自变量,以丙酸产量为响应值,对上述因素的最佳水平范围进行了探讨与优化。实验结果表明,培养温度和pH对丙酸产量有显著性影响,并据此建立了相关的数学模型。得到的工艺参数的优选结果是:培养温度为29.75℃、pH为6.61、接种量为6.15%(v/v),丙酸产量最大预测值为17.96g/L。经过优化,丙酸产量提高了27.9%,实验值与预测值基本相符。     

丙酸杆菌代谢物与山梨酸钾抑菌作用比较研究

以一株费氏丙酸杆菌突变株为出发菌株,通过改变发酵培养基、接种量和初始培养pH值3方面,研究其代谢产物对大肠杆菌和沙门氏菌的抑菌作用,并与山梨酸钾的抑菌作用进行对比。结果表明:3种发酵培养基均对大肠杆菌和沙门氏菌均存在一定的抑制作用,其中以乳酸钠(sodium lactate broth,SLB)培养基发酵时,该菌株代谢产物的抑菌活性分别为25.3 AU/mL和18.3 AU/mL,结果要优于0.1%的山梨酸钾的抑菌活性(21.1 AU/mL和14.1 AU/mL);对于接种量而言,对大肠杆菌和沙门氏菌的抑菌活性最佳的接种量分别为6%和5%,其抑菌活性分别为28.1 AU/mL和18.0 AU/mL,抑菌效果均优于0.1%的山梨酸钾;对于不同培养pH值而言,对大肠杆菌和沙门氏菌的抑菌活性最适初始pH值分别为6.5和6,抑菌活性分别为27.6 AU/mL和14.5 AU/mL,其抑菌效果也优于0.1%的山梨酸钾。所以,选择在适宜条件下发酵所得的丙酸杆菌代谢物,对大肠杆菌和沙门氏菌的抑制效果要优于山梨酸钾。对丙酸杆菌代谢物抑菌作用的研究将为新型天然防腐剂的开发提供依据与试验数据支撑。     

影响丙酸菌生长和产酸因素的初步研究

研究了培养方式和各种培养条件对丙酸杆菌的生长、丙酸生物量及环境酸度变化的影响,初步确定丙酸杆菌发酵的初步优化培养方式、培养基的始初pH及不同浓度的营养成分对丙酸杆菌的生长和产酸量的影响,初步优化的培养基成分为葡萄糖3.0%,酵母膏2.0%,蛋白胨0.3%,氯化钴6ppm;培养方式静置有氧培养好;灭菌前pH7.0~7.5。