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本文拟研究肉桂醛在非抑菌浓度条件下对荧光假单胞菌(Pseudomonas fluorescens)FML05-2生物膜形成的抑制作用。首先测定了肉桂醛对模式细菌紫色杆菌(Chromobacterium violaceum)CVO26紫色素产生的影响;再对荧光假单胞菌FML05-2形成的生物膜以及与生物膜形成有关的重要因素胞外多糖进行了测定。结果表明:在非抑菌浓度40、20μg/m L条件下,肉桂醛对紫色杆菌CVO26紫色素的产生具有抑制作用,抑制率分别为31.53%、17.90%;对荧光假单胞菌FML05-2生物膜形成的抑制率分别为44.22%、21.77%;对荧光假单胞菌FML05-2胞外多糖产生的抑制率分别为15.72%、5.34%。因此,肉桂醛在非抑菌浓度条件下对荧光假单胞菌FML05-2生物膜的形成具有抑制作用。 相似文献
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Lee KH Kim BS Keum KS Yu HH Kim YH Chang BS Ra JY Moon HD Seo BR Choi NY You YO 《Journal of food science》2011,76(9):H226-H230
Curcuma longa (C. longa) has been used as a spice in foods and as an antimicrobial in Oriental medicine. In this study, we evaluated the inhibitory effects of an essential oil isolated from C. longa on the cariogenic properties of Streptococcus mutans (S. mutans), which is an important bacterium in dental plaque and dental caries formation. First, the inhibitory effects of C. longa essential oil on the growth and acid production of S. mutans were tested. Next, the effect of C. longa essential oil on adhesion to saliva-coated hydroxyapatite beads (S-HAs) was investigated. C. longa essential oil inhibited the growth and acid production of S. mutans at concentrations from 0.5 to 4 mg/mL. The essential oil also exhibited significant inhibition of S. mutans adherence to S-HAs at concentrations higher than 0.5 mg/mL. S. mutans biofilm formation was determined by scanning electron microscopy (SEM) and safranin staining. The essential oil of C. longa inhibited the formation of S. mutans biofilms at concentrations higher than 0.5 mg/mL. The components of C. longa essential oil were then analyzed by GC and GC-MS, and the major components were α-turmerone (35.59%), germacrone (19.02%), α-zingiberene (8.74%), αr-turmerone (6.31%), trans-β-elemenone (5.65%), curlone (5.45%), and β-sesquiphellandrene (4.73%). These results suggest that C. longa may inhibit the cariogenic properties of S. mutans. 相似文献
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对大蒜、肉桂等6种天然的香辛料分别采用水和80%乙醇进行提取并筛选出对副溶血弧菌抑菌能力较强的提取物,探究这些香辛料提取物对副溶血弧菌生物膜的抑制作用。研究结果表明大蒜、肉桂、丁香具有较强的抗菌作用,而花椒、小茴香、迷迭香则相对较弱。肉桂和大蒜的乙醇提取物对副溶血弧菌的最低抑菌浓度(Minimum inhibitory concentration,MIC)皆为6.25 mg/m L。亚抑菌浓度的提取物除了能够抑制副溶血弧菌生物膜的形成,还能抑制生物膜内细菌的代谢活性,减少细菌胞外多糖的分泌。激光共聚焦扫描显微镜(Confocal Laser Scanning Microscope,CLSM)观察发现,处理后死细胞的数量明显增多,且生物膜内多糖的含量明显变少。 相似文献
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P. Rungsri N. Akkarachaneeyakorn M. Wongsuwanlert S. Piwat P. Nantarakchaikul R. Teanpaisan 《Journal of dairy science》2017,100(10):7780-7787
The aims of this study were to evaluate whether short-term consumption of fermented milk containing Lactobacillus rhamnosus SD11 affected levels of oral microbiota in vivo and whether L. rhamnosus SD11 could colonize in the human mouth. We also monitored for potential side effects of the probiotic. The applicability of using L. rhamnosus SD11 compared with Lactobacillus bulgaricus as a starter culture for fermented milk was evaluated. After informed consent, 43 healthy young adults were recruited and randomly assigned to either the probiotic or control group and received fermented milk containing L. rhamnosus SD11 or L. bulgaricus, respectively, once daily for 4 wk. The numbers of mutans streptococci, lactobacilli, and total bacteria in saliva were counted at baseline and then after 4 and 8 wk. An oral examination was performed at baseline and after 8 wk. The persistence of L. rhamnosus SD11 was investigated by DNA fingerprinting using arbitrary primer-PCR. Results demonstrated that statistically significant reductions in mutans streptococci and total bacteria were observed in the probiotic group compared with the control group, and the number of lactobacilli was significantly increased in both groups after receiving fermented milks. Lactobacillus rhamnosus SD11 could be detected (in >80% of subjects) up to 4 wk following cessation of dosing among subjects in the probiotic group. No side effects were reported. Thus, L. rhamnosus SD11 could be used as a starter culture for fermented milk. Daily consumption of L. rhamnosus SD11-containing fermented milk for 4 wk may have beneficial effects on oral health by reducing salivary levels of mutans streptococci. The probiotic was apparently able to colonize the oral cavity for a longer time than previously reported. However, the potential benefits of probiotic L. rhamnosus SD11 on oral health require further evaluation with a larger group of volunteers in a longer-term study. 相似文献
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Assessing biofilm formation by Listeria monocytogenes strains 总被引:2,自引:0,他引:2
When a microtitre plate assay was used to quantify biofilm production by Listeria monocytogenes strains following growth in Tryptone Soy Broth (TSB) for 48 h at 20 degrees C, 127 of 138 strains (92.0%) were classified as weak, 9 of 138 strains (6.5%) as moderate and only 2 of 138 strains (1.5%) as strong biofilm formers. The strains included environmental, animal, food (persistent and sporadic strains) and clinical isolates previously typed using esterase electrophoresis (ESE) and multi-locus enzyme electrophoresis (MEE). Strains from different sources produced similar quantities of biofilm, whereas biofilm production by ESE type II strains, irrespective of source, was greater than that observed for other ESE types. No correlation between MEE type and biofilm production was observed. A Petri dish assay which allowed parallel quantification and microscopic examination of biofilms was used to examine biofilm formation by selected L. monocytogenes strains during growth in TSB for 14 days at 20 degrees C. Results from these assays showed that following prolonged incubation, some L. monocytogenes strains categorized as weak biofilm formers by the 48 h microtitre assay, were able to form biofilms similar in terms of quantity and structure to those produced by strains classified as strong or medium biofilm formers. Results from 14-day Petri dish assays confirmed 48 h microtitre assays regarding greater biofilm production by ESE type II strains compared to other ESE types of L. monocytogenes. Biofilm production was similar for ESE type II persistent and sporadic food isolates but reduced for ESE type II clinical strains. 相似文献
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目的优化超声辅助提取黑果腺肋花楸中花色苷工艺的方法。方法在单因素的基础上,研究提取温度、液料比和提取时间对花色苷提取率的影响,并利用响应面法对花色苷的提取条件进行优化。结果黑果腺肋花楸中花色苷提取的最佳工艺条件为:乙醇溶液(含0.5%的乙酸)浓度为40%,提取温度为43℃,超声时间为23 min,料液比为89:1(V:m),此条件下,黑果腺肋花楸中花色苷提取得率为(0.79±0.010)g/100g。结论本方法可以快速有效地提取黑果腺肋花楸中的花色苷。 相似文献
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This study was designed to evaluate the effect of NaCl on the biofilm formation of Listeria monocytogenes, Staphylococcus aureus, Shigella boydii, and Salmonella Typhimurium. The biofilm cells were cultured in media containing different NaCl concentrations (0% to 10%) for 10 d of incubation at 37 °C using a 24-well polystyrene microtiter plate, collected by swabbing methods, and enumerated using plate count method. The attachment and detachment kinetic patterns were estimated according to the modified Gompertz model. The cell surface hydrophobicity and auto-aggregation were observed at different NaCl concentrations. Most strains showed 2 distinctive phases at lower than 6% NaCl, while the numbers of adhered cells gradually increased throughout the incubation period at 4% to 10% NaCl. At 0% NaCl, the numbers of adhered L. monocytogenes, S. aureus, S. boydii, and S. Typhimurium cells rapidly increased up to 7.04, 6.47, 6.39, and 7.27 log CFU/cm(2), respectively, within 4 d of incubation. The maximum growth rate (k(A)) and specific growth rate (μ(A)) of adherent pathogenic cells were decreased with increasing NaCl concentration. Noticeable decline in the numbers of adherent cells was observed at low concentration levels of NaCl (<2%). The adherence abilities of foodborne pathogens were influenced by the physicochemical surface properties. The hydrophobicity and auto-aggregation enhanced the biofilm formation during the incubation periods. Therefore, this study could provide useful information to better understand the adhesion and detachment capability of foodborne pathogens on food contact surfaces. 相似文献
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Nowadays, food industry is facing challenges connected with the preservation of the highest possible quality of fruit products obtained after processing. Attention has been drawn to Aronia fruits due to numerous health promoting properties of their products. However, processing of Aronia, like other berries, leads to difficulties that stem from the preparation process, as well as changes in the composition of bioactive compounds. Consequently, in this study, Aronia commercial juice was subjected to different drying techniques: spray drying, freeze drying and vacuum drying with the temperature range of 40–80 °C. All powders obtained had a high content of total polyphenols. Powders gained by spray drying had the highest values which corresponded to a high content of total flavonoids, total monomeric anthocyanins, cyaniding-3-glucoside and total proanthocyanidins. Analysis of the results exhibited a correlation between selected bioactive compounds and their antioxidant capacity. In conclusion, drying techniques have an impact on selected quality parameters, and different drying techniques cause changes in the content of bioactives analysed. Spray drying can be recommended for preservation of bioactives in Aronia products. Powder quality depends mainly on the process applied and parameters chosen. Therefore, Aronia powders production should be adapted to the requirements and design of the final product. 相似文献
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The exosome is an evolutionarily conserved 10-mer complex involved in RNA metabolism, located in both the nucleus and the cytoplasm. The cytoplasmic exosome plays an important role in mRNA turnover through its 3'→5' exonucleolytic activity. The superkiller (SKI) phenotype of yeast was originally identified as an increase of killer toxin production due to elevated levels of the L-A double-stranded RNA (dsRNA) Totivirus and its satellite toxin-encoding M dsRNA. Most SKI genes were later shown to be either components of the exosome or modulators of its activity. Variations in the amount of Totivirus are, thus, good indicators of yeast exosome activity, and can be used to analyse its components. Furthermore, if exosome proteins of higher eukaryotes were functional in S. cerevisiae, these viruses would provide a simple tool to analyse their function. In this work, we have found that hCSL4, the human orthologue of SKI4 in the yeast exosome, rescues the null phenotype of the deletion mutant. hCsl4p shares with Ski4p conserved S1 RNA-binding domains, but lacks the N-terminal third of Ski4p. Nevertheless, it interacts with the Dis3p exonuclease of yeast exosome, and partially complements the superkiller phenotype of ski4-1 mutation. The elimination of the N-terminal third of Ski4p does not affect its activity, indicating that it is dispensable for RNA degradation. We have also identified the point mutation G152E in hCSL4, equivalent to the ski4-1 mutation G253E, which impairs the activity of the protein, thus validating our approach of using yeast RNA virus to analyse the exosome of higher eukaryotes. 相似文献
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目的研究阪崎克罗诺肠杆菌生物膜的形成特性。方法采用结晶紫染色法检测生物膜形成量,考察培养时间、培养温度以及初始pH值3个环境因子对阪崎克罗诺肠杆菌生物膜形成的影响。结果结果表明培养时间、培养温度以及初始pH值对生物膜形成影响较大,且各阪崎克罗诺肠杆菌的最佳成膜条件分别为:阪崎克罗诺肠杆菌CICC21550最适温度为30℃,最适PH为7,最佳培养时间为36h;阪崎克罗诺肠杆菌CICC 21562最适温度为30℃,最适pH为5,最佳培养时间为48 h;阪崎克罗诺肠杆菌CICC 21544最适温度为42℃,最适pH为7,最佳培养时间为24 h;阪崎克罗诺肠杆菌CICC 21563最适温度为30℃,最适pH为7,最佳培养时间为36 h。结论 4株阪崎克罗诺肠杆菌的生物被膜成膜能力由强及弱依次为阪崎克罗诺肠杆菌CICC 21550、21544、21563、21562。本研究为阪崎克罗诺肠杆菌生物膜相关研究提供理论参考。 相似文献
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Inhibition of Gallic Acid on the Growth and Biofilm Formation of Escherichia coli and Streptococcus mutans
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Dongyan Shao Jing Li Ji Li Ruihua Tang Liu Liu Junling Shi Qingsheng Huang Hui Yang 《Journal of food science》2015,80(6):M1299-M1305
New strategies for biofilm inhibition are becoming highly necessary because of the concerns to synthetic additives. As gallic acid (GA) is a hydrolysated natural product of tannin in Chinese gall, this research studied the effects of GA on the growth and biofilm formation of bacteria (Escherichia coli [Gram‐negative] and Streptococcus mutans [Gram‐positive]) under different conditions, such as nutrient levels, temperatures (25 and 37 °C) and incubation times (24 and 48 h). The minimum antimicrobial concentration of GA against the two pathogenic organisms was determined as 8 mg/mL. GA significantly affected the growth curves of both test strains at 25 and 37 °C. The nutrient level, temperature, and treatment time influenced the inhibition activity of GA on both growth and biofim formation of tested pathogens. The inhibition effect of GA on biofilm could be due to other factors in addition to the antibacterial effect. Overall, GA was most effective against cultures incubated at 37 °C for 24 h and at 25 °C for 48 h in various concentrations of nutrients and in vegetable wash waters, which indicated the potential of GA as emergent sources of biofilm control products. 相似文献
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《Journal of dairy science》2021,104(9):9521-9531
Bile salts is one of essential components of bile secreted into the intestine to confer antibacterial protection. Cronobacter species are associated with necrotizing enterocolitis in newborns and show a strong tolerance to bile salts. However, little attempt has been made to focus on the molecular basis of the tolerance to bile salts. In this study, we investigated the roles of tolC on growth, cell morphology, motility, and biofilm formation ability in Cronobacter malonaticus under bile salt stress. The results indicated that the absence of tolC significantly affected the colony morphology and outer membrane structure in a normal situation, compared with those of the wild type strain. The deletion of tolC caused the decline in resistance to bile salt stress, inhibition of growth, and observable reduction in relative growth rate and motility. Moreover, the bacterial stress response promoted the biofilm formation ability of the mutant strain. The expression of the AcrAB-TolC system (acrA, acrB, and tolC) was effectively upregulated compared with the control sample when exposed to different bile salt concentrations. The findings provide valuable information for deeply understanding molecular mechanisms about the roles of tolC under bile salt stress and the prevention and control of C. malonaticus. 相似文献
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Yingwang Ye Maofeng Zhang Rui Jiao Na Ling Xiyan Zhang Liaowang Tong Haiyang Zeng Jumei Zhang Qingping Wu 《Journal of dairy science》2018,101(1):66-74
Presence of Cronobacter malonaticus in powdered infant formula (PIF) poses a high risk to infant and public health. Cronobacter malonaticus has been widely distributed in food and food processing environments, and the true origin of C. malonaticus in PIF is poorly understood. Control and prevention of C. malonaticus is necessary for achieving microbial safety of PIF. However, little information about decontamination of C. malonaticus is available. In this study, effects of hydrogen peroxide on inactivation and morphological changes of C. malonaticus cells were determined. Furthermore, inhibitory effects of H2O2 on biofilm formation in C. malonaticus were also performed. Results indicated that H2O2 could completely inactivate C. malonaticus in sterile water with 0.06% H2O2 for 25 min, 0.08% H2O2 for 15 min, and 0.10% for 10 min, respectively, whereas the survival rates of C. malonaticus in tryptic soy broth medium significantly increased with the same treatment time and concentration of H2O2. In addition, morphological changes of C. malonaticus cells, including cell shrinkage, disruption of cells, cell intercession, and leakage of intercellular material in sterile water after H2O2 treatment, were more predominant than those in tryptic soy broth. Finally, significant reduction in biofilm formation by H2O2 was found using crystal violet staining, scanning electron microscopy, and confocal laser scanning microscopy detection compared with control samples. This is the first report to determine the effects of H2O2 on C. malonaticus cells and biofilm formation. The findings provided valuable information for practical application of H2O2 for decontamination of C. malonaticus in dairy processing. 相似文献
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Coralie Goetz Yannick D.N. Tremblay Daphnée Lamarche Andréanne Blondeau Annie M. Gaudreau Josée Labrie François Malouin Mario Jacques 《Journal of dairy science》2017,100(8):6454-6464
Coagulase-negative staphylococci (CNS) are considered to be commensal bacteria in humans and animals, but are now also recognized as etiological agents in several infections, including bovine mastitis. Biofilm formation appears to be an important factor in CNS pathogenicity. Furthermore, some researchers have proposed that CNS colonization of the intramammary environment has a protective effect against other pathogens. The mechanisms behind the protective effect of CNS have yet to be characterized. The aim of this study was to evaluate the effect of CNS isolates with a weak-biofilm phenotype on the biofilm formation of other staphylococcal isolates. We selected 10 CNS with a weak-biofilm phenotype and 30 staphylococcal isolates with a strong-biofilm phenotype for this study. We measured biofilm production by individual isolates using a standard polystyrene microtiter plate assay and compared the findings with biofilm produced in mixed cultures. We confirmed the results using confocal microscopy and a microfluidic system with low shear force. Four of the CNS isolates with a weak-biofilm phenotype (Staphylococcus chromogenes C and E and Staphylococcus simulans F and H) significantly reduced biofilm formation in approximately 80% of the staphylococcal species tested, including coagulase-positive Staphylococcus aureus. The 4 Staph. chromogenes and Staph. simulans isolates were also able to disperse pre-established biofilms, but to a lesser extent. We also performed a deferred antagonism assay and recorded the number of colony-forming units in the mixed-biofilm assays on differential or selective agar plates. Overall, CNS with a weak-biofilm phenotype did not inhibit the growth of isolates with a strong-biofilm phenotype. These results suggest that some CNS isolates can negatively affect the ability of other staphylococcal isolates and species to form biofilms via a mechanism that does not involve growth inhibition. 相似文献
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单增李斯特菌是一种重要的食源性致病菌,极易在食品接触表面形成难以清除的生物膜,导致食品持续性的污染。细菌生物膜在形成量、活细菌数量、微观结构等方面受到环境因素及菌株自身特性的影响。在单增李斯特菌的生物膜形成过程中,多种调控机制发挥着重要的作用。该文介绍了细菌生物膜的形成过程及影响单增李斯特菌生物膜形成的重要因素,简述了与单增李斯特菌生物膜相关的基因调控、胞外聚合物质分泌与群体感应系统调节的研究进展,有助于更好地理解其生物膜形成的复杂生理过程,为单增李斯特菌生物膜的污染及防控提供一定参考。 相似文献