Two-stage Nested PCR Effectiveness for Direct Detection of Vibrio vulnificus in Natural Samples

The nested primers designed to amplify a 222-base pair portion of the hemolysin gene, vvhA, were specific for all V. vulnificus strains tested. The nested PCR amplification, coupled with direct extraction of template DNA, revealed improved sensitivity sufficient for detection of 1 to 10 CFU V. vulnificus in 1 mL of seafood homogenates, and eliminated the need for enrichment culturing. Thereby, the nested PCR method achieved a broader applicability, making it effective for extensive use in identification of the pathogen in natural samples such as raw seafoods, seawater and sediments.     

贝叶斯优化方法在需钠弧菌生产1，3-丙二醇中的应用

1，3-丙二醇是一种重要的化工原料，生物法发酵制备1，3-丙二醇具有操作简便、反应条件温和、副产物少等优点，使用需钠弧菌作为新的工业底盘细胞生产1，3-丙二醇有很好的应用前景。高产菌株的构建过程中优化基因强度组合时，具有单次实验周期长、成本高且体系复杂、非线性强的特点。为了实现对1，3-丙二醇合成途径关键基因强度组合的快速优化，使用了一种以高斯过程回归算法为代理模型，以增益期望为采集函数的贝叶斯优化方法。在每轮迭代中，高斯过程回归算法用于拟合当前数据并预测未知点的概率分布，增益期望函数将概率分布映射到解空间中，选择解空间中最大值对应的点作为下一轮的实验点，实验后进入下一轮迭代。构建高产1，3-丙二醇的需钠弧菌过程中使用贝叶斯优化方法优化关键基因强度组合，在三轮迭代后搜索到了最优的基因强度组合，1，3-丙二醇的产量达到（13.01±0.63）g/L，较第一组实验点中最高值提高了8.32%。     

Improving Detection of Vibrio vulnificus in Octopus variabilis by PCR

PCR methods can detect foodborne pathogenic bacteria with simplicity, specificity and speed. In order to improve sensitivity and speed of PCR methods for detection of Vibrio vulnificus in small octopus homogenate, several media and culture conditions were compared. Modified brain heart infusion media containing 2% NaCl and adjusted to pH 8.0 and 30°C was most effective for enrichment of the bacteria. Procedures affecting the efficiency of template DNA extraction and target DNA amplification were also optimized. By these combined efforts, a PCR procedure capable of detecting V. vulnificus as low as 10 cells/mL within 10h was developed.     

肠衣损坏原因分析

在某盐渍肠衣生产过程中更改肠衣盐和储存温度后(由低温储存变为常温储存),成品肠衣在储存过程中产生了白色硬块,在使用过程中硬块处出现破洞。采用感官检验、物理性质及化学成分分析、扫描电镜及能谱分析、副溶血性弧菌检测、菌落总数检测等方法,对盐渍肠衣的损坏原因进行了分析。结果表明:储存环境温度的升高使微生物大量繁殖,是肠衣损坏的主要原因。     

Combining basic electrolyzed water pretreatment and mild heat greatly enhanced the efficacy of acidic electrolyzed water against Vibrio parahaemolyticus on shrimp

The objective of this study was to investigate the efficacy of acidic electrolyzed water (AEW) against Vibrio parahaemolyticus on shrimp. The shrimp was initially inoculated with V. parahaemolyticus(7-8 log CFU/g), and treated with AEW (AEW1 containing 51 mg/L of chlorine or AEW2 containing 78 mg/L of chlorine) or organic acids (2% AA and 2%LA) for 1 min or 5 min under different treated conditions. The effect of AEW was better than that of organic acids, the number of survival V. parahaemolyticus cells on shrimp was reduced by 0.9 log CFU/g after treatment for 5 min with AEW without vibration, while 1.0 log CFU/g bacteria cells reduced with vibration. No significant difference (p > 0.05) was observed between AEW and organic acids in the bactericidal activity with or without vibration. The effective order of temperatures on bactericidal activities of AEW was 50 °C > 20 °C > 4 °C, and a 3.1 log CFU/g reduction of V. parahaemolyticus cells on shrimp was detected with treatment of AEW at 50 °C. Mild heat greatly enhanced efficacy of electrolyzed water against V. parahaemolyticus. Basic electrolyzed water (BEW) (50 °C) pretreatment combined with AEW (50 °C) treatment remarkably reduced bacterial cells by 5.4 log CFU/g on shrimp after treatment for 5 min. There was a significant change in physicochemical properties (pH, ORP, ACC) of AEW, after it was used to wash shrimp (P < 0.05). This study suggests that BEW (50 °C) pretreatment followed by AEW (50 °C) treatment could be a possible method to effectively control V. parahaemolyticus contamination on shrimp.     

Polysulfone‐azo composite membrane: New preparative approach,importance in bactericidal and biofilm inhibition activities

The study in particular relates to a process for modifying surface of polymeric membrane and their biocidal activities. The modification process is based on absorption of 1, 3, phenylene diamine on the asymmetric polysulfone membrane and its diazo reaction. The azo compound (Bismarck brown) is characterized by LC‐mass, uv–vis spectra. The incorporation of azo compound into polysulfone asymmetric membrane is proved by ATR‐FTIR, SEM studies. The decrease in contact angle for modified surface proves the development of hydrophilic character. The modified membrane shows higher biocidal activity (for marine bacteria Vibrio sp.) compared to the virgin polysulfone membrane. The biofilm formation is inhibited for the modified membrane compared to virgin Polysulfone membrane. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Application of the combination index (CI)-isobologram equation to study the toxicological interactions of lipid regulators in two aquatic bioluminescent organisms

Pharmaceuticals in the aquatic environment do not appear singly and usually occur as complex mixtures, whose combined effect may exhibit toxicity to the aquatic biota. We report an environmental application of the combination index (CI)-isobologram equation, a method widely used in pharmacology to study drug interactions, to determine the nature of toxicological interactions of three fibrates toward two aquatic bioluminescent organisms, Vibrio fischeri and the self-luminescent cyanobacterial recombinant strain Anabaena CPB4337. The combination index-isobologram equation method allows computerized quantitation of synergism, additive effect and antagonism. In the Vibrio test, the fibrate combinations showed antagonism at low effect levels that turned into an additive effect or synergism at higher effect levels; by contrast, in the Anabaena test, the fibrate combinations showed a strong synergism at the lowest effect levels and a very strong antagonism at high effect levels. We also evaluated the nature of the interactions of the three fibrates with a real wastewater sample in the cyanobacterial test. We propose that the combination index-isobologram equation method can serve as a useful tool in ecotoxicological assessment.     

Quorum Sensing in the Squid-Vibrio Symbiosis

Quorum sensing is an intercellular form of communication that bacteria use to coordinate group behaviors such as biofilm formation and the production of antibiotics and virulence factors. The term quorum sensing was originally coined to describe the mechanism underlying the onset of luminescence production in cultures of the marine bacterium Vibrio fischeri. Luminescence and, more generally, quorum sensing are important for V. fischeri to form a mutualistic symbiosis with the Hawaiian bobtail squid, Euprymna scolopes. The symbiosis is established when V. fischeri cells migrate via flagella-based motility from the surrounding seawater into a specialized structure injuvenile squid called the light organ. The cells grow to high cell densities within the light organ where the infection persists over the lifetime of the animal. A hallmark of a successful symbiosis is the luminescence produced by V. fischeri that camouflages the squid at night by eliminating its shadow within the water column. While the regulatory networks governing quorum sensing are critical for properly regulating V. fischeri luminescence within the squid light organ, they also regulate luminescence-independent processes during symbiosis. In this review, we discuss the quorum-sensing network of V. fischeri and highlight its impact at various stages during host colonization.     

致病性弧菌检测新技术研究进展

随着人们对水产品需求的增加及致病性弧菌引发的食源性疾病的流行，致病性弧菌对水产养殖业及人类健康造成了巨大威胁，基于此，致病性弧菌检测新技术的开发变得尤为迫切。本文介绍了包括免疫学方法、核酸检测方法、基于生物芯片的检测方法、基于核酸适配体的检测方法、基于肽质量指纹图谱技术的检测方法、基于生物传感器技术的检测方法在内的六项检测技术，分析了其优缺点及其在致病性弧菌中的应用。最后，总结了致病性弧菌检测新技术的研究现状，结合新兴技术指出未来研究方向，为致病性弧菌的快速检测提供参考。