迷迭香和甘草复配液对切片火腿李斯特菌抑制效果及品质影响的研究

利用迷迭香、甘草(1:1,v/v)复配液:对接种和不接种李斯特菌的切片火腿喷洒不同浓度的香辛料提取物复配液后,采用真空包装,分别测定其在贮存过程中微生物指标和理化指标的变化,以考察其保鲜效果.相对未经保鲜液处理的对照,喷洒不同浓度香辛料提取物复配液对切片火腿中李斯特菌和常见腐败菌都具有很强的抑制作用,且提取物复配液的抑菌效果与浓度呈正比关系.贮存28d时喷洒2.5、5.0、10.0mg/mL提取物复配液的切片火腿中李斯特菌数与对照相比分别降低了2.5、2.6和3.0个对数循环;乳酸菌菌数与对照相比分别降低了2.4、2.6和2.8个对数循环;总菌数与对照相比分别降低2.9、3.0和3.2个对数循环;均与对照组差异显著(P<0.05).对不接种李斯特菌的切片火腿(真空包装)喷洒不同浓度复配液后进行理化指标测定,结果表明,香辛料提取物对肉色无不良影响,对脂质氧化也起到了较好的抑制作用.     

浙江地区不同经济品种杨梅叶提取物的抑菌活性研究

为开发替代抗生素使用的植物源饲料添加剂,本实验对浙江地区不同经济品种的杨梅叶提取物进行了抑菌活性的研究.采用水提和醇提法对东魁、荸荠、丁岙和晚稻等九种经济品种杨梅叶进行了提取和真空浓缩.分别测定了提取物得率和抑菌效果,结果表明,九种杨梅叶提取物均具有抑菌活性,晚稻品种水提液抑菌效果显著高于其他品种,醇提液抑菌效果的水晶种、深红种差异不大,高于其他品种.     

The Role of Antimicrobial Peptides in Preterm Birth

Antimicrobial peptides (AMPs) are short cationic amphipathic peptides with a wide range of antimicrobial properties and play an important role in the maintenance of immune homeostasis by modulating immune responses in the reproductive tract. As intra-amniotic infection and microbial dysbiosis emerge as common causes of preterm births (PTBs), a better understanding of the AMPs involved in the development of PTB is essential. The altered expression of AMPs has been reported in PTB-related clinical presentations, such as preterm labor, intra-amniotic infection/inflammation, premature rupture of membranes, and cervical insufficiency. Moreover, it was previously reported that dysregulation of AMPs may affect the pregnancy prognosis. This review aims to describe the expression of AMPs associated with PTBs and to provide new perspectives on the role of AMPs in PTB.     

石榴皮多酚的微波辅助提取及提取物抗氧化与抑菌作用研究

通过单因素实验、正交实验,用微波辅助法提取石榴皮多酚类化合物,确定了石榴多酚提取的最优工艺条件:40%(体积分数)乙醇作溶剂,料液比(g∶mL)1∶35,微波功率为242 W,提取时间60 s,提取三次,以该优化条件提取时,多酚粗提物的得率26.52%.同时还研究了石榴皮提取物对羟自由清除作用和小鼠肝匀浆脂质过氧化的抑制作用,研究显示,其半抑制浓度IC50,EC50分别为0.288 mg/mL,0.0079 mg/mL.同时还通过测定抑菌圈直径和最小抑菌浓度(MIC)研究了石榴多酚的提取物对大肠杆菌和枯草杆菌的抑制作用,实验表明:石榴皮多酚类物质对大肠杆菌和枯草杆菌有较好的抑制作用,其作用在浓度为1g/L时最为显著;对应的抑菌圈直径分别为1.15 cm和1.25cm;其最小抑菌浓度分别为0.5 g/L和2 g/L.     

Towards the Native Binding Modes of Antibiotics that Target Lipid II

The alarming rise of antimicrobial resistance (AMR) imposes severe burdens on healthcare systems and the economy worldwide, urgently calling for the development of new antibiotics. Antimicrobial peptides could be ideal templates for next-generation antibiotics, due to their low propensity to cause resistance. An especially promising branch of antimicrobial peptides target lipid II, the precursor of the bacterial peptidoglycan network. To develop these peptides into clinically applicable compounds, detailed information on their pharmacologically relevant modes of action is of critical importance. Here we review the binding modes of a selection of peptides that target lipid II and highlight shortcomings in our molecular understanding that, at least partly, relate to the widespread use of artificial membrane mimics for structural studies of membrane-active antibiotics. In particular, with the example of the antimicrobial peptide nisin, we showcase how the native cellular membrane environment can be critical for understanding of the physiologically relevant binding mode.     

Antibacterial PET-Silk fabric containing Salvia officinalis extract

In this study, novel PET-Silk fabric is introduced via finishing PET fabric with silk hydrogel and Salvia officinalis extract. The silk hydrogel was prepared from waste silk; morphology and chemical structure were evaluated by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy methods. The results indicated the 3D porous network and crystalline structure of hydrogel. The polyester fabric was finished with prepared hydrogel. Contact angle and water uptake of modified fabric were assessed. S. officinalis extract was used as an antibacterial agent. Results of antibacterial tests confirmed a remarkable antibacterial effect of finished fabrics with the extract.     

Critical review of controlled release packaging to improve food safety and quality

ABSTRACT

Controlled release packaging (CRP) is an innovative technology that uses the package to release active compounds in a controlled manner to improve safety and quality for a wide range of food products during storage. This paper provides a critical review of the uniqueness, design considerations, and research gaps of CRP, with a focus on the kinetics and mechanism of active compounds releasing from the package. Literature data and practical examples are presented to illustrate how CRP controls what active compounds to release, when and how to release, how much and how fast to release, in order to improve food safety and quality.     

超声辅助水蒸气蒸馏法提取蓝桉叶中精油的工艺优化及其抑菌活性研究

目的初步探明蓝桉叶精油最佳提取工艺及不同提取工艺条件下蓝桉叶精油得率与其抗菌活性的差异性。方法以桉叶油得率为评价指标,采用超声辅助水蒸气蒸馏法,通过单因素与正交试验确定桉叶油最佳提取工艺。并检验正交试验各组合桉叶油对金黄色葡萄球菌、大肠杆菌和黑曲霉的抑菌效果。结果桉叶油的最佳提取工艺条件为料液比1:4(g/mL),超声时间25min,超声功率200W,蒸馏时间5h,桉叶油得率为1.51%。而抑菌试验结果表明,不同提取工艺所得桉叶油的抑菌活性存在差异。对金黄色葡萄球菌和大肠杆菌而言,料液比1:6(g/mL),超声时间30 min,超声功率180 W,蒸馏时间5 h时抑菌活性最强,抑菌圈直径分别为(11.92±0.20)mm(n=3)和(10.25±0.35)mm(n=3),对应的桉叶油得率为1.28%;对黑曲霉而言,料液比1:7(g/mL),超声时间30min,超声功率200W,蒸馏时间7h时抑菌活性最强,抑菌圈直径为(12.25±0.29)mm(n=3),对应的桉叶油得率为1.38%。结论精油得率与其抑菌活性无相关性,针对不同的目标微生物需要单独优化提取工艺来获得相应的微生物抑菌剂。     

LuxS/AI-2群体感应系统及其对细菌致病性和耐药性的调控

群体感应是指细菌在生长过程中产生一些低分子量的信号分子, 通过信号分子来感知种群密度变化, 从而调节相关基因表达和群体行为的过程。不同细菌利用不同类型的信号分子交流, 其中自诱导分子2(Autoinducer-2, AI-2)信号分子存在于革兰氏阳性菌和革兰氏阴性菌中, 是一种种间交流的信号分子。AI-2是一类呋喃酰硼酸二酯, 其合成依赖于S-核糖同型半胱氨酸酶(S-ribosylhomocysteinase, LuxS), 能调控细菌的多种重要生理过程, 包括毒素的分泌、生物膜的形成和耐药性等。本文综述了LuxS/AI-2群体感应系统及其对细菌致病性和耐药性的影响及调控作用, 以期为解析食源性致病菌的致病性及耐药性作用机制、研制新型抗菌药物、控制食源性致病菌的感染提供新思路。     

Novel approach for development of eco-friendly antimicrobial textile material for health care application

The use of biopolymers for the development of eco-friendly textile materials for medical and health care sector is now essential so as to minimize the infection due to harmful bacteria, especially for skin injury. The present research works are aimed at developing sustainable nano-structured textile material treated with tetrahydroxy curcumin and evaluate its application in the areas of wound management. Stable oil in water nanoemulsion of tetrahydroxy curcumin derivative was developed to improve its solubility using high-pressure homogenization technique. Textile material was impregnated with optimized nanoemulsion having particle size distribution 100–300 nm, zeta potential ?30.1–?31.1 mV and drug content 80–83.3% by exhaust method using cyclodextrin and polycarboxylic acid as a cross-linking agent. Treated sample was observed to be more effective against B. Subtilis and E.Coli when evaluated for antimicrobial activity. The results were optimized using response surface methodology. It was observed that, 0.5% nanoemulsion at 100 °C for 15-min period of time shows maximum inhibition.