Assembly of Immunogenic Protein Particles toward Advanced Synthetic Vaccines

Immunogenic carrier proteins such as the non-toxic diphtheria toxin variant, cross-reacting material 197 (CRM197), are widely used in subunit vaccine formulations to boost immunogenicity of chemically conjugated antigens. Conjugate vaccines are inherently expensive due to laborious manufacturing steps. Here, this work develops a particulate vaccine platform based on using engineered Escherichia coli to assemble CRM197-antigen fusion proteins into discrete submicron-sized particles. This approach enables precise loading of diverse antigens and epitopes enhancing their immunogenicity. A cost-effective, high-yield, and scalable biomanufacturing process is developed. Purified particulate CRM197-antigen vaccines are ambient-temperature stable. CRM197 particles incorporating pathogen-specific antigens or epitopes from SARS-CoV-2, Streptococcus pyogenes (group A), and Mycobacterium tuberculosis induced cell-mediated and humoral immune responses mediating protective immunity in respective animal models of infection. The CRM197 particle vaccine platform is versatile, enabling co-delivery of selected antigens/epitopes together with immunogenic CRM197 as discrete stable particles avoiding laborious manufacture of soluble CRM197 and antigen followed by chemical conjugation.     

有机氰废水的生物降解性和微生物毒性试验

在30℃条件下,采用血清瓶液体置换系统,模拟厌氧消化反应设备条件,测定了丙烯腈、腈纶生产过程废水等各种高浓度有机氰废水的厌氧生物可降解性及废水中丙烯腈、乙腈、聚合物和氰化物这些主要污染物质对产甲烷菌的毒性。结果表明,丙烯腈生产一段、二段急冷废水和腈纶生产工艺废水的厌氧生物可降解性能很差,3种废水的厌氧生物可降解性分别为36.3%、45.8%和53%,比代表一般石油化工工业废水生化性能的苯酚的厌氧生物可降解性(78%)低得多。废水中主要污染物对产甲烷活性抑制性较强,丙烯腈、乙腈、聚合物、氰化物使厌氧菌产甲烷活性降低50%的质量浓度分别为85、320、1300、4.5mg/L。其毒素类型分别为:丙烯腈在低质量浓度下为代谢毒素,厌氧菌产甲烷活性在恢复试验中得到恢复;在高质量浓度(>120mg/L)下为生理毒素,毒性引起的产甲烷活性受抑制,但在短时期内得到恢复。氰化物在低质量浓度下为生理毒素;较高质量浓度下(>25mg/L)为杀菌性毒素,厌氧菌细胞已遭受严重破坏,无法修复。乙腈和聚合物始终为代谢毒素。     

食品中的化学性危害

化学危害可能来源于天然存在的化学物质,有意加入的化学物质,无意或偶尔进入的化学物质,会影响人体健康。介绍了化学性危害（食品添加剂与辅助剂类、天然毒素类和天然过敏源物质类及其它化学污染物）的来源及危害。     

Purification of Candida guilliermondii and Pichia ohmeri killer toxin as an active agent against Penicillium expansum

An antifungal assay with cell-free culture supernatant of Pichia ohmeri 158 and Candida guilliermondii P3 was tested against Penicillium expansum strain #2 at 25°C by measuring hyphal length and percentage conidia germination. C. guilliermondii was more effective against P. expansum conidia germination (58.15% inhibition), while P. ohmeri showed higher inhibition of mycelial growth (66.17%), indicating a probable mechanism associated with killer activity. This killer toxin (molecular mass <3 kDa) was partially purified by normal phase HPLC, using TSKgel Amide-80 analytical and preparative columns. Compared with crude extract, the killer toxin eluted from the post analytical column significantly inhibited P. expansum:% inhibition rose from 42.16 to 90.93% (C. guilliermondii) and 39.32 to 91.12% (P. ohmeri) (p < 0.05). The one-step purification process was adequate in isolating killer toxin from culture supernatant and also increased anti-Penicillium activity.     

Developmental Programming and Reprogramming of Hypertension and Kidney Disease: Impact of Tryptophan Metabolism

The concept that hypertension and chronic kidney disease (CKD) originate in early life has emerged recently. During pregnancy, tryptophan is crucial for maternal protein synthesis and fetal development. On one hand, impaired tryptophan metabolic pathway in pregnancy impacts fetal programming, resulting in the developmental programming of hypertension and kidney disease in adult offspring. On the other hand, tryptophan-related interventions might serve as reprogramming strategies to prevent a disease from occurring. In the present review, we aim to summarize (1) the three major tryptophan metabolic pathways, (2) the impact of tryptophan metabolism in pregnancy, (3) the interplay occurring between tryptophan metabolites and gut microbiota on the production of uremic toxins, (4) the role of tryptophan-derived metabolites-induced hypertension and CKD of developmental origin, (5) the therapeutic options in pregnancy that could aid in reprogramming adverse effects to protect offspring against hypertension and CKD, and (6) possible mechanisms linking tryptophan metabolism to developmental programming of hypertension and kidney disease.     

Anaerobic Biochemical Treatment of Wastewater Containing Highly Concentrated Organic Cyanogen

Abstract

The first and second stage of chilled wastewater in acrylic fibersitrile process and wastewater in acrylic fibers process are biodegraded under anaerobic conditions. Toxicity of acrylonitrile, acetonitrile, polymers, and cyanide in the wastewaters to the production of methane has been studied. Results suggest that the first and second stage chilled wastewaters from acrylonitrile process and wastewater from acrylic fibers process cannot be biodegraded well. COD_BD of the first and second stage chilled wastewaters from acrylonitrile process is 36.3 and 45.8. COD_BD of the wastewater from acrylic fibers process is 53.0. Acetonitrile, acrylonitrile, polymers, and cyanide are toxic to anaerobic bacteria in the highly concentrated organic cyanogens containing wastewater, inhibiting the methane-producing activity. Half inhibition concentration (50% IC) to anaerobic methane-producing activity is 1,300, 320, 85, and 50 mg/L for polymers, acetonitrile, acrylonitrile, and cyanide, respectively. Acrylonitrile is a metabolizing and physiological toxin, acetonitrile and polymers a metabolizing toxin, and cyanide a physiological and sterilizing toxin.     

Ultrasensitive diagnosis for an anthrax-protective antigen based on a polyvalent directed peptide polymer coupled to zinc oxide nanorods

A flexible poly-D-lysine polymer conjugated with different target-binding peptides is demonstrated with an ultralow concentration detection limit compared to those of other conventional detection systems. This polyvalent directed peptide polymer (PDPP) exhibits increased binding affinity and detects anthrax protective antigen at low levels using a well-known zinc oxide nanorod detection system.     

可降解玉米赤霉烯酮的重组过氧化物酶A4-Prx的纯化与活性研究

以来源于不动杆菌Acinetobacter sp.SM04的过氧化物酶A4-Prx的毕赤酵母工程表达菌株GS115/p PIC9K-A4-Prx为研究对象,从培养液中纯化重组过氧化物酶A4-Prx,分析其ZEA降解活力,并研究过氧化物酶A4-Prx的酶学特性。本论文首先研究了蛋白的纯化方法,通过一系列分离纯化手段得到纯的过氧化物酶A4-Prx,最终纯化倍数约为12,HPLC实验结果表明纯化后的过氧化物酶A4-Prx具有ZEA降解能力,且ZEA降解率达到63%。对过氧化物酶A4-Prx进行酶学特性研究,结果表明,p H和温度均对A4-Prx的过氧化物酶酶活有显著影响,p H 9.0和反应温度60℃时酶活最高,A4-Prx的最大酶活是204.1 U,此时过氧化氢浓度为9.7 m M。A4-Prx过氧化物酶反应受EDTA的抑制作用明显。本研究为过氧化物酶的酶学研究奠定了基础,为后续的A4-Prx降解机理研究提供先决条件,推动生物降解ZEA研究的进展。     

Short communication: First detection of Panton-Valentine leukocidin–positive methicillin-resistant Staphylococcus aureus ST30 in raw milk taken from dairy cows with mastitis in South Korea

We identified 199 Staphylococcus aureus isolates from quarter milk samples of 1,289 dairy cattle between 2014 and 2018. About 66% of the isolates were resistant to at least 1 antimicrobial agent; the highest rate of resistance was to penicillin, followed by resistance to ampicillin, erythromycin, and sulfadimethoxine. We obtained 30 methicillin-resistant S. aureus (MRSA) strains from 6 farms in 3 provinces. The MRSA strains exhibited a significantly higher resistance rate to most of the tested antimicrobials than the oxacillin-susceptible strains. The MRSA strains represented 5 genotypes: ST72-t324-SCCmec IV (n = 14), ST30-t1752-SCCmec IV (n = 8), ST188-t189-SCCmec NT (n = 6), ST188-t2284-SCCmec NT (n = 1), and NT-NT-SCCmec IV (n = 1). One of the ST188 MRSA strains represented a novel staphylococcal protein A (spa) type (t2284). In addition, 7 of the 8 ST30 MRSA strains were Panton-Valentine leukocidin (PVL)–positive and carried various staphylococcal enterotoxin encoding genes. This is the first report of PVL-positive ST30 MRSA-t1752-SCCmec IV from bovine mastitis in Korea. All of ST72-t324-SCCmec IV MRSA strains carried staphylococcal enterotoxin and leukotoxin encoding genes. They were also sensitive to most of the tested non-β-lactam antimicrobials. In contrast, ST188-t189 MRSA strains were resistant to multiple antimicrobials and predominantly carried the leukotoxin encoding gene. Taken together, these findings may indicate that dairy cows could be a major source for spreading MRSA strains, and contaminated milk could be a vehicle for transmission. Suitable hygienic measures should be established in dairy farms and processing plants to limit the likelihood of introducing MRSA into the food chain.