BACTERIOCIN-LIKE ACTIVITY FROM WEISSELLA CONFUSA AND PEDIOCOCCUS ACIDILACTICI ISOLATED FROM TRADITIONAL THAI FERMENTED SAUSAGES

Bacteriocin-like activity (BLA) was screened in 133 strains of lactic acid bacteria (LAB) isolated from traditional Thai fermented sausages. The inhibition assay against the test organisms showed that eight out of 133 isolates (CP1-15, CP2-11, CP3-1, CP7-3, CP10-3, CP11-6, CP14-1 and CP14-4) suppressed the growth of Bacillus cereus and four (CP1-15, CP7-3, CP14-2 and CP14-3) suppressed the growth of Staphylococcus aureus but none could suppress the growth of Escherichia coli and Salmonella sp. The isolates with the highest activity against the two Gram positive test strains (CP3-1 for B. cereus and CP7-3 for S. aureus) were further investigated for the effect of heat treatment at different pH values and for combined effects of dual mixtures. The increase in heating temperature (between 65 and 100 \ub0C) and time (between 5 and 60 min) significantly decreased BLA, while the changes in pH (between 4 and 6) had little effect. When the filtrates of the two isolates were mixed, BLA seemed to be synergistic against each test strain. Regression equations were obtained by fitting the experimental percent inhibition data with second-order polynomial equations. The simulated data agreed well with the experimental data within 10 % when the filtrates were incubated at 65 \ub0C for 5, 15, 30 and 60 min and at 80 \ub0C for 5, 15 and 30 min. The isolates CP3-1 and CP7-3, which had an antagonistic effect against the two strains of Gram positive foodborne bacteria, were formerly identified as Weissella confusa and Pediococcus acidilactici, respectively. It is the researcher\u92s belief that this is the first report on BLA from W. confusa against B. cereus

The Use of Flagella and Motility for Plant Colonization and Fitness by Different Strains of the Foodborne Pathogen Listeria monocytogenes

The role of flagella and motility in the attachment of the foodborne pathogen Listeria monocytogenes to various surfaces is mixed with some systems requiring flagella for an interaction and others needing only motility for cells to get to the surface. In nature this bacterium is a saprophyte and contaminated produce is an avenue for infection. Previous studies have documented the ability of this organism to attach to and colonize plant tissue. Motility mutants were generated in three wild type strains of L. monocytogenes by deleting either flaA, the gene encoding flagellin, or motAB, genes encoding part of the flagellar motor, and tested for both the ability to colonize sprouts and for the fitness of that colonization. The motAB mutants were not affected in the colonization of alfalfa, radish, and broccoli sprouts; however, some of the flaA mutants showed reduced colonization ability. The best colonizing wild type strain was reduced in colonization on all three sprout types as a result of a flaA deletion. A mutant in another background was only affected on alfalfa. The third, a poor alfalfa colonizer was not affected in colonization ability by any of the deletions. Fitness of colonization was measured in experiments of competition between mixtures of mutant and parent strains on sprouts. Here the flaA and motAB mutants of the three strain backgrounds were impaired in fitness of colonization of alfalfa and radish sprouts, and one strain background showed reduced fitness of both mutant types on broccoli sprouts. Together these data indicate a role for flagella for some strains to physically colonize some plants, while the fitness of that colonization is positively affected by motility in almost all cases

MouR controls the expression of the Listeria monocytogenes Agr system and mediates virulence

The foodborne pathogen Listeria monocytogenes (Lm) causes invasive infection in susceptible ani- mals and humans. To survive and proliferate within hosts, this facultative intracellular pathogen tightly coordinates the expression of a complex regulatory network that controls the expression of virulence fac- tors. Here, we identified and characterized MouR, a novel virulence regulator of Lm. Through RNA-seq transcriptomic analysis, we determined the MouR regulon and demonstrated how MouR positively con- trols the expression of the Agr quorum sensing sys- tem (agrBDCA) of Lm. The MouR three-dimensional structure revealed a dimeric DNA-binding transcrip- tion factor belonging to the VanR class of the GntR superfamily of regulatory proteins. We also showed that by directly binding to the agr promoter region, MouR ultimately modulates chitinase activity and biofilm formation. Importantly, we demonstrated by in vitro cell invasion assays and in vivo mice infec- tions the role of MouR in Lm virulence.Peer reviewe

Formation of biofilms on stainless steel by Pseudomonas fluorescens and Listeria monocytogenes

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN032686 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Bacteriocin-like activity from weissella confusa and pediococcus acidilactici isolated from tradtional Thai fermented sausages

Bacteriocin-like activity (BLA) was screened in 133 strains of lactic acid bacteria (LAB) isolated from traditional Thai fermented sausages. The inhibition assay against the test organisms showed that eight out of 133 isolates (CP1-15, CP2-11, CP3-1, CP7-3, CP10-3, CP11-6, CP14-1 and CP14-4) suppressed the growth of Bacillus cereus and four (CP1-15, CP7-3, CP14-2 and CP14-3) suppressed the growth of Staphylococcus aureus but none could suppress the growth of Escherichia coli and Salmonella sp. The isolates with the highest activity against the two Gram positive test strains (CP3-1 for B. cereus and CP7-3 for S. aureus) were further investigated for the effect of heat treatment at different pH values and for combined effects of dual mixtures. The increase in heating temperature (between 65 and 100 °C) and time (between 5 and 60 min) significantly decreased BLA, while the changes in pH (between 4 and 6) had little effect. When the filtrates of the two isolates were mixed, BLA seemed to be synergistic against each test strain. Regression equations were obtained by fitting the experimental percent inhibition data with second-order polynomial equations. The simulated data agreed well with the experimental data within 10 % when the filtrates were incubated at 65 °C for 5, 15, 30 and 60 min and at 80 °C for 5, 15 and 30 min. The isolates CP3-1 and CP7-3, which had an antagonistic effect against the two strains of Gram positive foodborne bacteria, were formerly identified as Weissella confusa and Pediococcus acidilactici, respectively. It is the researcher s belief that this is the first report on BLA from W. confusa against B. cereus

การพัฒนาน้ำหมักมะขามป้อมพร้อมดื่มDevelopment of Vinegar Drink from Fermented Indian Gooseberry

งานวิจัยนี้ได้ศึกษากระบวนการหมักน้ำส้มสายชูจากมะขามป้อม เริ่มด้วยการใช้ยีสต์ Saccharomyces cerevisiae TISTR 5019 นาน 2 วัน และหมักต่อด้วยเชื้อแบคทีเรีย Acetobacter pasteurianus TISTR 102 นาน 4 สัปดาห์ เพื่อให้ได้เป็นน้ำส้มสายชูหมักจากมะขามป้อม โดยหาอัตราส่วนที่เหมาะสมระหว่างเนื้อมะขามป้อมต่อน้ำ 3 ระดับ คือ 1 : 1, 1 : 3 และ 2 : 1 ปริมาตรทั้งหมดเป็น 3,000 มิลลิลิตร พบว่าที่อัตราส่วน 1 : 1 ได้ปริมาณกรดทั้งหมดและปริมาณเอทานอลสูงที่สุด เท่ากับร้อยละ 2.97 และ 1.35 กรัมต่อลิตร (0.135%) ตามลำดับ จากนั้นนำไปพัฒนาเป็นน้ำหมักมะขามป้อมพร้อมดื่มโดยนำน้ำหมักที่ได้จากแต่ละอัตราส่วนมาผสมกับน้ำผึ้ง น้ำและกรดซิติก นำมาทดสอบทางประสาทสัมผัสพบว่า อัตราส่วน 1 : 1 ได้รับคะแนนความชอบสูงสุด จึงใช้เป็นสูตรมาตรฐานในการปรับเปลี่ยนสารให้ความหวาน (น้ำผึ้ง น้ำตาลฟรักโทส และน้ำหวานดอกมะพร้าว) ร้อยละ 10, 13 และ 16 และปริมาณของกรดซิตริก (ร้อยละ 0.03, 0.06 และ 0.09) เพื่อหาปริมาณที่เหมาะสม โดยสูตรที่ได้คะแนนการยอมรับจากผู้ทดสอบสูงสุด ประกอบด้วย น้ำหมักมะขามป้อม 8% น้ำผึ้ง 13% กรดซิตริก 0.06% และน้ำ 78% มีค่าความเป็นกรด-เบส เท่ากับ 3.25 ปริมาณของแข็งที่ละลายน้ำได้ทั้งหมด เท่ากับ 12.43 ปริมาณกรดในรูปของกรดอะซิติก เท่ากับ 0.55% ปริมาณเอทานอลเหลืออยู่ เท่ากับ 0.08 กรัมต่อลิตร (หรือ 0.008%) ค่าสี a*, b* และ L* เท่ากับ 1.54±0.05, –0.03±0.05 และ 23.72±0.13 ตามลำดับ มีปริมาณวิตามินซีค่อนข้างสูงคือ 68.19 มิลลิกรัมต่อ 100 กรัมของตัวอย่าง ความสามารถในการยับยั้งอนุมูลอิสระลงครึ่งหนึ่ง (IC 50) เท่ากับ 0.11 ปริมาณสารประกอบฟีนอลิก เท่ากับ 1.69 มิลลิกรัม กรดกาลิค/มิลลิลิตร ส่วนข้อมูลทางโภชนาการ 1 หน่วยบริโภค (200 มิลลิลิตร) ให้พลังงาน 100 กิโลแคลอรี่ และเหล็ก 4% ของปริมาณที่แนะนำต่อวันสำหรับคนไทย มีต้นทุน 19.28 บาท ต่อ 1 หน่วยบริโภค นอกจากนี้ไม่พบการเจริญของแบคทีเรียทั้งหมด ยีสต์และรา ในน้ำหมักมะขามป้อมพร้อมดื่มที่เก็บรักษานาน 4 สัปดาห์ ที่อุณหภูมิ 4 องศาเซลเซียสThis research studied the fermentation of Indian gooseberry by Saccharomyces cerevisiae TISTR 5019 for 2 days, followed by Acetobacter pasteurianus TISTR 102 for 4 weeks in order to obtain Indian gooseberry vinegar. Three ratios of Indian gooseberry fruit and water (1 : 1, 1 : 3 and 2 : 1) in the total volume of 3000 mL were investigated. The results showed that the ratio of fruit to water at 1 : 1 had the highest ethanol and total acidity equal to 1.35 g/l (0.135%) and 2.97%, respectively. The Indian gooseberry cider beverage was further developed from the fermented vinegar by mixing with citric acid, honey and water. Sensory evauation showed that the beverage using fermented juice at the ratio of 1 : 1 obtained the most acceptability from the panelists. The further development was carried out by varying the percentage of different sweeteners (honey, sugar, fructose and coconut syrup) 10, 13 and 16%, as well as three levels of citric acid (0.03, 0.06 and 0.09%). The organoleptic tests revealed that the formula contained 8% Indian gooseberry vinegar, 13% honey, 0.06% citric acid and 78% water received the highest scores of overall acceptance and taste. The drink had pH 3.25 and 12.43% of total soluble solids. The total acidity (acetic acid equivalent) was 0.55%, and 0.08 g/l (0.008%) ethanol left. The colour values of a*, b* and L* were 1.54±0.05, –0.03±0.05 and 23.72±0.13, respectively. Vitamin C content was 68.19 mg/100 g. The antioxidant ability measured in terms of IC50 was 0.11. The phenolic compounds were 1.69 mg GAE/mL. Nutritional value of 200 mL (per 1 serving) was 100 Kcal and contained 4% iron according to recommended Thai daily intake (RDI). The cost per serving was 19.28 Baht. Growth of bacteria, yeast and mold were not found throughout the storage duration of 4 weeks at 4oC

Acute oral toxicity of zein nanoparticles with encapsulated gamma oryzanol in Sprague Dawley rats

Gamma oryzanol (GO) is well known for its antioxidant activity and health-promoting benefits. The gamma oryzanol-loaded zein nanoparticles (GOZNs) were successfully prepared in our previous study. In the present work, the acute oral toxicity of GOZNs was evaluated based on OECD guideline 420. GOZNs were fabricated by the liquid-liquid dispersion and lyophilized. The samples displayed a mean diameter of 311.20±3.01 nm and high loading capacity of 311.22±7.97 to 322.69±5.67 mg-GO/g-powder after 42-day storage at -18oC. Healthy female Sprague Dawley rats (8 weeks of age) were used for the experiments. Five female rats were administered a single dose of 2,000 mg GO/kg body weight via the oral route. Observations of toxicity signs were recorded for the first 24 hours, and the changes in the general physical conditions were monitored for 14 days before the gross necropsy on day 15. The results show that Sprague Dawley rats exhibited normal growth, and neither mortality nor acute toxicity signs were observed throughout the study period. The findings revealed that GOZNs did not have acute toxicity and were safe when administered orally in Sprague Dawley rats for short periods with LD50 > 2,000 mg/kg