Search results for: sulfate reducing bacteria

Authors: Genesis Julyus T. Agcaoili, Esperanza C. Cabrera

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Thirty (30) isolates of lactic acid bacteria (LAB) from traditionally-prepared fermented products specifically fermented soy-bean paste, fermented mustard and fermented rice-fish mixture were studied for their in vitro antimicrobial and cytotoxic activities. Seventeen (17) isolates were identified as Lactobacillus plantarum, while 13 isolates were identified as Enterococcus spp using 16s rDNA sequences. Disc diffusion method was used to determine the antibacterial activity of LAB against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922), while the modified agar overlay method was used to determine the antifungal activity of LAB isolates on the yeast Candida albicans, and the dermatophytes Microsporum gypseum, Trichophyton rubrum and Epidermophyton floccosum. The filter-sterilized LAB supernatants were evaluated for their cytotoxicity to mammalian colon cancer cell lines (HT-29 and HCT116) and normal human dermal fibrolasts (HDFn) using resazurin assay (PrestoBlueTM). Colchicine was the positive control. No antimicrobial activity was observed against the bacterial test organisms and the yeast Candida albicans. On the other hand, all of the tested LAB strains were fungicidal for all the test dermatophytes. Cytotoxicity index profiles of the supernatants of the 15 randomly picked LABs and negative control (brain heart infussion broth) suggest nontoxicity to the cells when compared to colchicine, whereas all LAB supernatants were found to be cytotoxic to HT-29 and HCT116 colon cancer cell lines. Results provide strong support for the role of the lactic acid bacteria studied in antimicrobial treatment and anticancer therapy.

Keywords: antimicrobial, fermented products, fungicidal activity, lactic acid bacteria, probiotics

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Authors: M. Naimi, M. B. Khaled

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The aim of the present work was to test in vitro inhibition of food pathogens and spoilage bacteria by crude bacteriocins from autochthonous lactic acid bacteria. Thirty autochthonous lactic acid bacteria isolated previously, belonging to the genera: Lactobacillus, Carnobacterium, Lactococcus, Vagococcus, Streptococcus, and Pediococcus, have been screened by an agar spot test and a well diffusion assay against Gram-positive and Gram-negative harmful bacteria: Bacillus cereus, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 8739, Salmonella typhimurium ATCC 14028, Staphylococcus aureus ATCC 6538, and Pseudomonas aeruginosa under conditions means to reduce lactic acid and hydrogen peroxide effect to select bacteria with high bacteriocinogenic potential. Furthermore, crude bacteriocins semiquantification and heat sensitivity to different temperatures (80, 95, 110°C, and 121°C) were performed. Another exploratory test concerning the response of St. aureus ATCC 6538 to the presence of crude bacteriocins was realized. It has been observed by the agar spot test that fifteen candidates were active toward Gram-positive targets strains. The secondary screening demonstrated an antagonistic activity oriented only against St. aureus ATCC 6538, leading to the selection of five isolates: Lm14, Lm21, Lm23, Lm24, and Lm25 with a larger inhibition zone compared to the others. The ANOVA statistical analysis reveals a small variation of repeatability: Lm21: 0.56%, Lm23: 0%, Lm25: 1.67%, Lm14: 1.88%, Lm24: 2.14%. Conversely, slight variation was reported in terms of inhibition diameters: 9.58± 0.40, 9.83± 0.46, and 10.16± 0.24 8.5 ± 0.40 10 mm for, Lm21, Lm23, Lm25, Lm14and Lm24, indicating that the observed potential showed a heterogeneous distribution (BMS = 0.383, WMS = 0.117). The repeatability coefficient calculated displayed 7.35%. As for the bacteriocins semiquantification, the five samples exhibited production amounts about 4.16 for Lm21, Lm23, Lm25 and 2.08 AU/ml for Lm14, Lm24. Concerning the sensitivity the crude bacteriocins were fully insensitive to heat inactivation, until 121°C, they preserved the same inhibition diameter. As to, kinetic of growth , the µmax showed reductions in pathogens load for Lm21, Lm23, Lm25, Lm14, Lm24 of about 42.92%, 84.12%, 88.55%, 54.95%, 29.97% in the second trails. Inversely, this pathogen growth after five hours displayed differences of 79.45%, 12.64%, 11.82%, 87.88%, 85.66% in the second trails, compared to the control. This study showed potential inhibition to the growth of this food pathogen, suggesting the possibility to improve the hygienic food quality.

Keywords: exploratory test, lactic acid bacteria, crude bacteriocins, spoilage, pathogens

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Authors: Dibyakanta Seth, Hari Niwas Mishra, Sankar Chandra Deka

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Microencapsulation is an established method of protecting bacteria from the adverse conditions. An improved extrusion spraying technique was used to encapsulate mixed bacteria culture of S. thermophilus and L. bulgaricus using sodium alginate as the coating material. The effect of nozzle air pressure (200, 300, 400 and 500 kPa), sodium alginate concentration (1%, 1.5%, 2%, 2.5% and 3% w/v), different concentration of calcium chloride (0.1, 0.2, 1 M) and initial cell loads (10⁷, 10⁸, 10⁹ cfu/ml) on the viability of encapsulated bacteria were investigated. With the increase in air pressure the size of microcapsules decreased, however the effect was non-significant. There was no significant difference (p > 0.05) in the viability of encapsulated cells when the concentration of calcium chloride was increased. Increased level of sodium alginate significantly increased the survival ratio of encapsulated bacteria (P < 0.01). Encapsulation with 3% alginate was treated as optimum since a higher concentration of alginate increased the gel strength of the solution and thus was difficult to spray. Under optimal conditions 3% alginate, 10⁹ cfu/ml cell load, 20 min hardening time in 0.1 M CaCl2 and 400 kPa nozzle air pressure, the viability of bacteria cells was maximum compared to the free cells. The microcapsules made at the optimal condition when mixed with yoghurt and subjected to spray drying at 148°C, the survival ratio was 2.48×10⁻¹ for S. thermophilus and 7.26×10⁻¹ for L. bulgaricus. In contrast, the survival ratio of free cells of S. thermophilus and L. bulgaricus were 2.36×10⁻³ and 8.27×10⁻³, respectively. This study showed a decline in viable cells count of about 0.5 log over a period of 7 weeks while there was a decline of about 1 log in cultures which were incorporated as free cells in yoghurt. Microencapsulation provided better protection at higher acidity compared to free cells. This study demonstrated that microencapsulation of yoghurt culture in sodium alginate is an effective technique of protection against extreme drying conditions.

Keywords: extrusion, microencapsulation, spray drying, sweetened yoghurt

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Authors: Phillip Minnaar, Neil Jolly, Louisa Beukes, Santiago Benito-Saez

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Dovyalis caffra is a tree found on the African continent. Limited information exists on the effect of acetous fermentation on the phytochemicals of Kei-apple fruit. The phytochemical content of vinegars is derived from compounds present in the fruit the vinegar is made of. Kei-apple fruit juice was co-inoculated with Schizosaccharomyces pombe and Saccharomyces cerevisiae to induce alcoholic fermentation (AF). Acetous fermentation followed AF, using an acetic acid bacteria consortium as an inoculant. Juice had the lowest pH and highest total acidity (TA). The wine had the highest pH and vinegars lowest TA. Total soluble solids and L-malic acid decreased during AF and acetous fermentation. Volatile acidity concentration was not different among vinegars. Gallic, syringic, caffeic, p-coumaric, and chlorogenic acids increased during acetous fermentation, whereas ferulic, sinapic, and protocatechuic acids decreased. Chlorogenic acid was the most abundant phenolic acid in both wines and vinegars. It is evident from this investigation that Kei-apple vinegar is a source of plant-derived phenolics, which evolved through fermentation. However, the AAB selection showed minimal performance with respect to VA production. Acetic acid bacteria selection for acetous fermentation should be reconsidered, and the reasons for the decrease of certain phenolic acids during acetous fermentation needs to be investigated.

Keywords: acetic acid bacteria, acetous fermentation, liquid chromatography, phenolic acids

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Authors: B. Samuel Raj, Solomon R. D. Jebakumar

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Microbial fuel cells (MFCs) are an emerging and promising method for achieving sustainable energy since they can remove contaminated organic matter and simultaneously generate electricity. Our approach was driven in three different ways like Bacterial fuel cell, Soil Microbial fuel cell (Soil MFC) and Plant Microbial fuel cell (Plant MFC). Bacterial MFC: Sulphate reducing bacteria (SRB) were isolated and identified as the efficient electricigens which is able to produce ±2.5V (689mW/m2) and it has sustainable activity for 120 days. Experimental data with different MFC revealed that high electricity production harvested continuously for 90 days 1.45V (381mW/m2), 1.98V (456mW/m2) respectively. Biofilm formation was confirmed on the surface of the anode by high content screening (HCS) and scanning electron Microscopic analysis (SEM). Soil MFC: Soil MFC was constructed with low cost and standard Mudwatt soil MFC was purchased from keegotech (USA). Vermicompost soil (V1) produce high energy (± 3.5V for ± 400 days) compared to Agricultural soil (A1) (± 2V for ± 150 days). Biofilm formation was confirmed by HCS and SEM analysis. This finding provides a method for extracting energy from organic matter, but also suggests a strategy for promoting the bioremediation of organic contaminants in subsurface environments. Our Soil MFC were able to run successfully a 3.5V fan and three LED continuously for 150 days. Plant MFC: Amaranthus candatus (P1) and Triticum aestivium (P2) were used in Plant MFC to confirm the electricity production from plant associated microbes, four uniform size of Plant MFC were constructed and checked for energy production. P2 produce high energy (± 3.2V for 40 days) with harvesting interval of two times and P1 produces moderate energy without harvesting interval (±1.5V for 24 days). P2 is able run 3.5V fan continuously for 10days whereas P1 needs optimization of growth conditions to produce high energy.

Keywords: microbial fuel cell, biofilm, soil microbial fuel cell, plant microbial fuel cell

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Authors: Nesrine Lenchi, Salima Kebbouche-Gana, Laddada Belaid, Mohamed Lamine Khelfaoui, Mohamed Lamine Gana

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Saline lakes are extreme hypersaline environments that are considered five to ten times saltier than seawater (150 – 300 g L-1 salt concentration). Hypersaline regions differ from each other in terms of salt concentration, chemical composition and geographical location, which determine the nature of inhabitant microorganisms. In order to explore the diversity of moderate and extreme halophiles Bacteria in Chott Tinsilt (East of Algeria), an isolation program was performed. In the first time, water samples were collected from the saltern during pre-salt harvesting phase. Salinity, pH and temperature of the sampling site were determined in situ. Chemical analysis of water sample indicated that Na +and Cl- were the most abundant ions. Isolates were obtained by plating out the samples in complex and synthetic media. In this study, seven halophiles cultures of Bacteria were isolated. Isolates were studied for Gram’s reaction, cell morphology and pigmentation. Enzymatic assays (oxidase, catalase, nitrate reductase and urease), and optimization of growth conditions were done. The results indicated that the salinity optima varied from 50 to 250 g L-1, whereas the optimum of temperature range from 25°C to 35°C. Molecular identification of the isolates was performed by sequencing the 16S rRNA gene. The results showed that these cultured isolates included members belonging to the Halomonas, Staphylococcus, Salinivibrio, Idiomarina, Halobacillus Thalassobacillus and Planococcus genera and what may represent a new bacterial genus.

Keywords: bacteria, Chott, halophilic, 16S rRNA

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Authors: Wilailak Siripornadulsil, Siriyanapat Tasaku, Jutamas Buahorm, Surasak Siripornadulsil

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The objectives of this study were to isolate LAB from various sources, dietary supplement, Thai traditional fermented food, and freshwater fish and to characterize their potential as probiotic cultures. Out of 1,558 isolates, 730 were identified as LAB based on isolation on MRS agar supplemented with a bromocresol purple indicator and CaCO3 and gram-positive, catalase and oxidase negative characteristics. Eight isolates showed the potential probiotic properties including tolerance to acid, bile salt and heat, proteolytic, amylolytic and lipolytic activities and oxalate-degrading capability. They all showed the antimicrobial activity against some Gram-negative and Gram-positive pathogenic bacteria. Based on 16S rDNA sequence analysis, they were identified as Enterococcus faecalis BT2 and MG30, Leconostoc mesenteroides SW64 and Pediococcus pentosaceous BD33, CF32, NP6, PS34 and SW5. The health beneficial effects and food safety will be further investigated and developed as a probiotic or protective culture used in Nile tilapia belly flap meat fermentation.

Keywords: probiotic, lactic acid bacteria, pathogen, protective culture

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Authors: Zahid Rehman, TorOve Leiknes

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Quorum sensing (QS) is the process by which bacteria communicate with each other through small signaling molecules, such as N-acylhomoserine lactones (AHLs). Also, certain bacteria have the ability to degrade AHL molecules by a process referred to as quorum quenching (QQ); therefore, QQ can be used to control bacterial infections and biofilm formation. In this study, we aimed to identify new species of bacteria with QQ activities. To achieve this, sediments from Red Sea were collected either in the close vicinity of Sea grass or from area with no vegetation. From these samples, we isolated 72 bacterial strains and tested their ability to degrade/inactivate AHL molecules. Chromobacterium violaceum based bioassay was used in initial screening of isolates for QQ activity. The QQ activity of the positive isolates was further confirmed and quantified by employing liquid chromatography and mass spectrometry. These analyses showed that isolated bacterial strain could degrade AHL molecules with different acyl chain length and modifications. Sequencing of 16S-rRNA genes of positive isolates revealed that they belong to three different genera. Specifically, two isolates belong to genus Erythrobacter, four to Labrenzia and one isolate belongs to Bacterioplanes. Time course experiment showed that isolate belonging to genus Erythrobacter could degrade AHLs faster than other isolates. Furthermore, these isolates were tested for their ability to inhibit formation of biofilm and degradation of 3OXO-C12 AHLs produced by P. aeruginosa PAO1. Our results showed that isolate VG12 is better at controlling biofilm formation. This aligns with the ability of VG12 to cause at least 10-fold reduction in the amount of different AHLs tested.

Keywords: quorum sensing, biofilm, quorum quenching, anti-biofouling

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Authors: Mimeche Leila, Debabeche Mahmoud

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It is question to study and to value the possibility of settling the process of purification by plants (constructed wetland) to treat the domestic waste water of Biskra, city in a semi-arid environment with grave problems of. According to the bibliography, the process of treatment by plants is considered as more advantageous than the classic techniques. It is the use of beds with macrophytes where the purification is made by the combined action of plants and micro-organisms in a filtering bed. The micro-organisms which are aerobic bacteria and\or anaerobic have for main function to degrade the polluting materials. Plants in the macrophytes beds have for function to serve as support in the development of bacteria and to favour also their development. In this study, we present a preliminary experimental analysis of the potentialities of treatment of some macrpohytes plants, implanted in basins filled of gravel. Analyses physico chemical and bacteriological of the waste water indicate a good elimination of the polluting materials, and put in evidence the purifier power of these plants, in association with bacteria. The obtained results seem to be interesting and encourage deepening the study for other types of plants in other conditions.

Keywords: constructed wetlands, macrophytes, sewage treatment, wastewater

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Authors: Munir Ashraf, Shagufta Riaz

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Personal protective equipment (PPE) and bioactive textiles are highly important for the health care of front line hospital workers, patients, and the general population to be safe from highly infectious diseases. This was even more critical in the wake of COVID-19 outbreak. Most of the medical textiles are inactive against various viruses and bacteria, hence there is a need to wash them frequently to avoid the spread of microorganisms. According to survey conducted by the world health organization, more than 500 million people get infected from hospitals, and more than 13 million died due to these hospitals’ acquired deadly diseases. The market available PPE are though effective against the penetration of pathogens and to kill bacteria but, they are not breathable and active against different viruses. Therefore, there was a great need to develop textiles that are not only effective against bacteria, fungi, and viruses but also are comfortable to the medical personnel and patients. In the present study, waterproof breathable, and biologically active textiles were developed using antiviral and antibacterial nanomaterials. These nanomaterials like TiO₂, ZnO, Cu, and Ag were immobilized at the surface of cotton fabric by using different silane coupling agents and electroless deposition that they retained their functionality even after 30 industrial laundering cycles. Afterwards, the treated fabrics were coated with a waterproof breathable film to prevent the permeation of liquid droplets, any particle or microorganisms greater than 80 nm. The developed cotton fabric was highly active against bacteria and viruses. The good durability of nanomaterials at the cotton surface after several industrial washing cycles makes this fabric an ideal candidate for bioactive textiles used in the medical field.

Keywords: antibacterial, antiviral, cotton, durable

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Authors: G. Amariei, K. Boltes, R. Rosal, P. Leton

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Wastewater treatment plants (WWTPs) are supposed to hold an important place in the reduction of emerging contaminants, but provide an environment that has potential for the development and/or spread of adaptation, as bacteria are continuously mixed with contaminants at sub-inhibitory concentrations. Reviewing the literature, there are little data available regarding the use of adapted bacteria forming activated sludge community for toxicity assessment, and only individual validations have been performed. Therefore, the aim of this work was to study the toxicity of Triclosan (TCS) and Ibuprofen (IBU), individually and in binary combination, on adapted activated sludge (AS). For this purpose a battery of biomarkers were assessed, involving oxidative stress and cytotoxicity responses: glutation-S-transferase (GST), catalase (CAT) and viable cells with FDA. In addition, we compared the toxic effects on adapted bacteria with unadapted bacteria, from a previous research. Adapted AS comes from three continuous-flow AS laboratory systems; two systems received IBU and TCS, individually; while the other received the binary combination, for 14 days. After adaptation, each bacterial culture condition was exposure to IBU, TCS and the combination, at 12 h. The concentration of IBU and TCS ranged 0.5-4mg/L and 0.012-0.1 mg/L, respectively. Batch toxicity experiments were performed using Oxygraph system (Hansatech), for determining the activity of CAT enzyme based on the quantification of oxygen production rate. Fluorimetric technique was applied as well, using a Fluoroskan Ascent Fl (Thermo) for determining the activity of GST enzyme, using monochlorobimane-GSH as substrate, and to the estimation of viable cell of the sludge, by fluorescence staining using Fluorescein Diacetate (FDA). For IBU adapted sludge, CAT activity it was increased at low concentration of IBU, TCS and mixture. However, increasing the concentration the behavior was different: while IBU tends to stabilize the CAT activity, TCS and the mixture decreased this one. GST activity was significantly increased by TCS and mixture. For IBU, no variations it was observed. For TCS adapted sludge, no significant variations on CAT activity it was observed. GST activity it was significant decreased for all contaminants. For mixture adapted sludge the behaviour of CAT activity it was similar to IBU adapted sludge. GST activity it was decreased at all concentration of IBU. While the presence of TCS and mixture, respectively, increased the GST activity. These findings were consistent with the viability cells evaluation, which clearly showed a variation of sludge viability. Our results suggest that, compared with unadapted bacteria, the adapted bacteria conditions plays a relevant role in the toxicity behaviour towards activated sludge communities.

Keywords: adapted sludge community, mixture, PPCPs, toxicity

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Authors: Karthick Gopalan, Selvamohan Thankiah

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Biosurfactants are lipid compounds produced by microbes, which are amphipathic molecules consisting of hydrophophic and hydrophilic domains. In the present investigation, ten bacterial strains were isolated from petroleum oil contaminated sites near petrol bunk. Oil collapsing test, haemolytic activity were used as a criteria for primary isolation of biosurfactant producing bacteria. In this study, all the bacterial strains gave positive results. Among the ten strains, two were observed as good biosurfactant producers, they utilize the diesel as a sole carbon source. Optimization of biosurfactant producing bacteria isolated from petroleum oil contaminated sites was carried out using different parameters such as, temperature (20ºC, 25ºC, 30ºC, 37ºC and 45ºC), pH (5,6,7,8 & 9) and nitrogen sources (ammonium chloride, ammonium carbonate and sodium nitrate). Biosurfactants produced by bacteria were extracted, dried and quantified. As a result of optimization of parameters the suitable values for the production of more amount of biosurfactant by the isolated bacterial species was observed as 30ºC (0.543 gm/lt) in the pH 7 (0.537 gm/lt) with ammonium nitrate (0.431 gm/lt) as sole carbon source.

Keywords: isolation and identification, biosurfactant, microorganism, bioaugmentation

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Authors: R. A. Lahmer, A. P. Williams, S. Townsend, S. Baker, D. L. Jones

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Chitosan-arginine (Ch-arg) has been proposed as an anti-microbial agent to reduce the proliferation of spoilage and pathogenic bacteria within meat products destined for human consumption. In the current experiment its use as an antimicrobial packaging material was examined. Two different concentrations of chitosan-arginine (0.05 and 0.15 % w/w) were blended into a cellulose film (Ch-arg film). When placed in contact with chicken and beef juice inoculated with a lux-marked strain of E. coli O157, the film incorporating the highest Ch-arg concentration resulted in a small reduction of E. coli O157 in chicken juice; however, there was no effect of the Ch-arg film on E. coli O157 in beef juice. The lack of observed effect in the beef juice experiment we ascribe to insufficient surface-to-surface contact between the film and the bacteria in the beef juice and the greater presence of other Ch-arg reactive components in the juice (e.g. fats, blood cells). Results suggest that, in combination with other anti microbials, Ch-arg packaging may offers some potential for limiting the growth of pathogenic bacteria in foodstuffs; however, further research is needed to enhance their anti-microbial performance.

Keywords: cross-contamination, foodborne pathogen, polymer film, shelf life

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Authors: E. Soboleva, E. Sergachyova, S. G. Davydenko, T. V. Meledina

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Problem of food preservation is extremely important for mankind. Viscous damage ("illness") of bread results from development of Bacillus spp. bacteria. High temperature resistant spores of this microorganism are steady against 120°C) and remain in bread during pastries, potentially causing spoilage of the final product. Scientists are interested in further characterization of bread spoiling Bacillus spp. species. Our aim was to find weather yeast Saccharomyces cerevisiae strains that are able to produce natural antimicrobial killer factor can preserve bread illness. By diffusion method, we showed yeast antagonistic activity against spore-forming bacteria. Experimental technological parameters were the same as for bakers' yeasts production on the industrial scale. Risograph test during dough fermentation demonstrated gas production. The major finding of the study was a clear indication of the presence of killer yeast strain antagonistic activity against rope in bread causing bacteria. After demonstrating antagonistic effect of S. cerevisiae on bacteria using solid nutrient medium, we tested baked bread under provocative conditions. We also measured formation of carbon dioxide in the dough, dough-making duration and quality of the final products, when using different strains of S. cerevisiae. It is determined that the use of yeast S. cerevisiae RCAM 01730 killer strain inhibits appearance of rope in bread. Thus, natural yeast antimicrobial killer toxin, produced by some S. cerevisiae strains is an anti-rope in bread protector.

Keywords: bakers' yeasts, killer toxin, rope in bread, Saccharomyces cerevisiæ

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Authors: Yong Geun Yun, Jong Hui kim, Sang Ho Baik

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This study was carried out to develop a fermented dandelion (Tarazacum officinale) beverage using lactic acid bacteria with cinnamoyl esterase (CE) activity isolated from human feces. Lactic acid bacteria were screened based on bacterial survival ability in dandelion extract and CE activity. Dandelion extract fermented by Lactobacillus acidophilus F-46 (LA-F46) maintained approximately 105-106 log CFU/mL over an 8 days period. After fermented dandelion beverage (FDB) with LA-46 for 8 days at 37oC the pH was decreased from pH 7.0 to 3.5. Antioxidant activity by using DPPH radical scavenging activity of the prepared FDB was significantly increased compared to that of non-fermented dandelion beverage (NFDB). Moreover, CE activity was significantly enhanced during fermentation and showed the approximately 4.3 times increased concentration of caffeic acid up to 9.91 mg/100 mL after 8 days of incubation compared to NFDB. Therefore, it concluded that dandelion can be a good source for preparing a functional beverage and fermentation by LA-F46 enhanced the food functionality with enhanced caffeic acids.

Keywords: cinnamoyl esterase, dandelion, fermented beverage, lactic acid bacteria

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Authors: Priyanka Gupta, Nilanjana Bairagi, Deepti Gupta

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New pathogenic strains of microbes are continually emerging and resistance of bacteria to antibiotics is growing. Hospitals in India have a high burden of infections in their intensive care units and general wards. Rising incidence of hospital infections is a matter of great concern in India. This growth is often attributed to the absence of effective infection control strategies in healthcare facilities. Government, therefore, is looking for cost effective strategies that are effective against HAIs. One possible method is by application of an antimicrobial finish on the uniform. But there are limited studies to show the effect of antimicrobial activity of antimicrobial finish treated nurses’ uniforms in a real hospital set up. This paper proposes a prospective non-destructive sampling technique, based on the use of a detachable fabric patch, to assess the effectiveness of silver based antimicrobial agent across five wards in a tertiary care government hospital in Delhi, India. Fabrics like polyester and polyester cotton blend fabric which are more prevalent for making coats were selected for the study. Polyester and polyester cotton blend fabric was treated with silver based antimicrobial (AM) finish. At the beginning of shift, a composite patch of untreated and treated fabric respectively was stitched on the abdominal region on the left and right side of the washed white coat of participating nurse. At the end of the shift, the patch was removed and taken for bacterial sampling on Brain Heart Infusion (BHI) plates. Microbial contamination on polyester and blend fabrics after 6 hours shift was compared in Brain Heart Infusion broth (BHI). All patches treated with silver based antimicrobial agent showed decreased bacterial counts. Percent reduction in the bacterial colonies after the antimicrobial treatment in both fabrics was 81.0 %. Antimicrobial finish was equally effective in reducing microbial adhesion on both fabric types. White coats of nurses become progressively contaminated during clinical care. Type of fabric used to make the coat can affect the extent of contamination which is higher on polyester cotton blend as compared to 100% polyester. The study highlights the importance of silver based antimicrobial finish in the area of uniform hygiene. Bacterial load can be reduced by using antimicrobial finish on hospital uniforms. Hospital staff uniforms endowed with antimicrobial properties may be of great help in reducing the occurrence and spread of infections.

Keywords: antimicrobial finish, bacteria, infection control, silver, white coat

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Authors: Elizabeth G. Hereford, Geoffrey W. Gearner

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Logan’s Branch, within the Triplett Creek Watershed of Rowan County, Kentucky, is a waterway located near important agricultural and residential areas. Part of Logan’s Branch flows over an exposed black shale formation with elevated radioactivity and heavy metals. Three sites were chosen in relation to the formation and sampled five times over a thirty-day period during the recreational season. A fourth site in North Fork in Rowan County, Kentucky was also sampled periodically as it too has contact with the shale formation. These sites were then sampled monthly. All samples are analyzed for concentrations of Escherichia coli, heterotrophic bacteria, and total coliform bacteria utilizing the membrane filtration method and various culture media. Current data suggests that the radioactivity of the shale formation influences the bacteriological growth present in the waterway; however, further data will be collected and compared with that of my colleagues to confirm this trend.

Keywords: bacteriological analysis, Escherichia coli, heterotrophic bacteria, radioactive black shale formation, water quality

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Authors: Lotem Sarid, Meirav Trebicz-Geffen, Serge Ankri

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Queuosine (Q) is a naturally occurring modified nucleoside that occurs in the first position of transfer RNA anticodons such as Asp, Asn, His, and Tyr. As eukaryotes lack pathways to synthesize queuine, the nucleobase of queuosine, they must obtain it from their diet or gut microbiota. Our previous work investigated the effects of queuine on the physiology of the eukaryotic parasite Entamoeba histolytica and defined the enzyme EhTGT responsible for its incorporation into tRNA. To our best knowledge, it is unknown how E. histolytica salvages Q from gut bacteria. We used N-acryloyl-3-aminophenylboronic acid (APB) PAGE analysis to demonstrate that E. histolytica trophozoites can salvage queuine from Q or E. coli K12 but not from the modified E. coli QueC strain, which cannot produce queuine. Next, we examined the role of EhDUF2419, a protein with homology to DNA glycosylase, as a queuine salvage enzyme in E. histolytica. When EhDUF2419 expression is silenced, it inhibits Q's conversion to queuine, resulting in a decrease in Q-tRNA levels. We also observed that Q protects control trophozoites from oxidative stress (OS), but not siEhDUF2419 trophozoites. Overall, our data reveal that EhDUF2419 is central for the salvaging of queuine from bacteria and for the resistance of the parasite to OS.

Keywords: entamoeba histolytica, epitranscriptomics, gut microbiota, queuine, queuosine, response to oxidative stress, tRNA modification.

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Authors: Ayman M. Ibrahim, Jinpeng Cai, Peilun Shen, Dianwen Liu

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The difference in promoting sulfurization between different ammonium salts and its anion's effect on the sulfurization of the malachite surface was systematically studied. Therefore, this study takes malachite, a typical copper oxide mineral, as the research object, field emission scanning electron microscopy and energy-dispersive X-ray analysis (FESEM‒EDS), X-ray photoelectron spectroscopy (XPS), and other analytical and testing methods, as well as pure mineral flotation experiments, were carried out to examine the superiority of the ammonium salts as the sulfurizing reagent of malachite at the microscopic level. Additionally, the promoting effects of ammonium sulfate and ammonium phosphate on the malachite sulfurization of xanthate-flotation were compared systematically from the microstructure of sulfurized products, elemental composition, chemical state of characteristic elements, and hydrophobicity surface evolution. The FESEM and AFM results presented that after being pre-treated with ammonium salts, the adhesion of sulfurized products formed on the mineral surface was denser; thus, the flake radial dimension product was significantly greater. For malachite sulfurization flotation, the impact of ammonium phosphate in promoting sulfurization is weaker than ammonium sulfate. The reason may be that hydrolyzing phosphate consumes a substantial quantity of H+ in the solution, which hastens the formation of the copper-sulfur products, decreasing the adhesion stability of copper-sulfur species on the malachite surface.

Keywords: sulfurization flotation, adsorption characteristics, malachite, hydrophobicity

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Authors: Vojtech Stejskal, Hana Skalova, Petr Kvapil, George Hutchinson

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Algae growth has been an important issue in water management of water plants, ponds and lakes, swimming pools, aquaculture & fish farms, gardens or golf courses for last decades. There are solutions based on chemical or biological principles. Apart of these traditional principles for inhibition of algae growth and biofilm production there are also physical methods which are very competitive compared to the traditional ones. Ultrasonic technology is one of these alternatives. Ultrasonic emitter is able to eliminate the biofilm which behaves as a host and attachment point for algae and is original reason for the algae growth. The ultrasound waves prevent majority of the bacteria in planktonic form becoming strongly attached sessile bacteria that creates welcoming layer for the biofilm production. Biofilm creation is very fast – in the serene water it takes between 30 minutes to 4 hours, depending on temperature and other parameters. Ultrasound device is not killing bacteria. Ultrasound waves are passing through bacteria, which retract as if they were in very turbulent water even though the water is visually completely serene. In these conditions, bacteria does not excrete the polysaccharide glue they use to attach to the surface of the pool or pond, where ultrasonic technology is used. Ultrasonic waves decrease the production of biofilm on the surfaces in the selected area. In case there are already at the start of the application of ultrasonic technology in a pond or basin clean inner surfaces, the biofilm production is almost absolutely inhibited. This paper talks about two different pilot applications – one in Czech Republic and second in United States of America, where the used ultrasonic technology (AlgaeControl) is coming from. On both sites, there was used Mezzo Ultrasonic Algae Control System with very positive results not only on biofilm production, but also algae growth in the surrounding area. Technology has been successfully tested in two different environments. The poster describes the differences and their influence on the efficiency of ultrasonic technology application. Conclusions and lessons learned can be possibly applied also on other sites within Europe or even further.

Keywords: algae growth, biofilm production, ultrasonic solution, ultrasound

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Authors: Azita Behbahaninia

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This research has been carried out to determine the water quality and physico-chemical properties Polour River, one of the most branch of Haraz River. Polour River was studied for a period of one year Samples were taken from different stations along the main branch of River polour. In water samples determined pH, DO, SO4, Cl, PO4, NO3, EC, BOD, COD, Temprature, color and number of Caliform per liter. ArcGIS was used for the zoning of phosphate concentration in the polour River basin. The results indicated that the river is polluted in polour village station, because of discharge domestic wastewater and also river is polluted in Ziar village station, because of agricultural wastewater and water is contaminated in aquaculture station, because of fish ponds wastewater. Statistical analysis shows that between independent traits and coliform regression relationship is significant at the 1% level. Coefficient explanation index indicated independent traits control 80% coliform and 20 % is for unknown parameters. The causality analysis showed Temperature (0.6) has the most positive and direct effect on coliform and sulfate has direct and negative effect on coliform. The results of causality analysis and the results of the regression analysis are matched and other forms direct and indirect effects were negligible and ignorable. Kruskal-Wallis test showed, there is different between sampling stations and studied characters. Between stations for temperature, DO, COD, EC, sulfate and coliform is at 1 % and for phosphate 5 % level of significance.

Keywords: coliform, GIS, pollution, phosphate, river

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Authors: Aliasghar Golmohammadian, Sona Rostampour Yasouri

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One of the most important intestinal pathogenic strains is E. coli O₁₅₇:H₇. This pathogenic bacterium is transmitted to humans through water and food. E. coli O₁₅₇:H₇ is the main cause of Hemorrhagic colitis (HC), Hemolytic Uremic Syndrome (HUS), Thrombotic Thrombocytopenic Purpura (TTP) and in some cases death. Since E. coli O₁₅₇:H₇ can be transmitted through the consumption of different foods, including vegetables, agricultural products, and fresh dairy products, this study aims to identify and isolate E. coli O₁₅₇:H₇ from wastewater by PCR technique. One hundred twenty samples of water and wastewater were collected by Falcom Sterile from Shahrood and Neka cities. The samples were checked for colony formation after appropriate centrifugation and cultivation in the specific medium of Sorbitol MacConkey Agar (SMAC) and other diagnostic media of E. coli O₁₅₇:H₇. Also, the plates were observed macroscopically and microscopically. Then, the necessary phenotypic tests were performed on the colonies, and finally, after DNA extraction, the PCR technique was performed with specific primers related to rfbE and stx2 genes. The number of 5 samples (6%) out of all the samples examined were determined positive by PCR technique with observing the bands related to the mentioned genes on the agarose gel electrophoresis. PCR is a fast and accurate method to identify the bacteria E. coli O₁₅₇:H₇. Considering that E. coli bacteria is a resistant bacteria and survives in water and food for weeks and months, the PCR technique can provide the possibility of quick detection of contaminated water. Moreover, it helps people in the community control and prevent the transfer of bacteria to healthy and underground water and agricultural and even dairy products.

Keywords: E. coli O₁₅₇:H₇, PCR, water, wastewater

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Authors: Lazic Marina, Sugden Scott, Sharma Kanta Hem, Sauvageau Dominic, Stein Lisa

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Methane is a highly potent greenhouse gas mostly released through anthropogenic activities. Methane represents a low-cost and sustainable feedstock used for the biological production of value-added compounds by bacteria known as methanotrophs. In addition to methane, these organisms can utilize methanol, another cheap carbon source that is a common industrial by-product. Alphaproteobacteria methanotrophs can utilize both methane and methanol to produce the biopolymer polyhydroxybutyrate. The goal of this study was to examine the effect of methanol on polyhydroxybutyrate production in Methylocystis sp. Rockwell and to identify the optimal methane: methanol ratio that will improve PHB without reducing biomass production. Three methane: methanol ratios (4, 2.5., and 0.5) and three nitrogen source (ammonium or nitrate) concentrations (10 mM, 1 mM, and 0.1 mM) were combined to generate 18 growing conditions (9 per carbon source). The production of polyhydroxybutyrate and biomass was analyzed at the end of growth. Overall, the methane: methanol ratios that promoted polyhydroxybutyrate synthesis without reducing biomass were 4 and 2.5 and the optimal nitrogen concentration was 1 mM for both ammonium and nitrate. The physiological mechanism behind the beneficial effect of combining methane and methanol as carbon sources remain to be discovered. One possibility is that methanol has a dual role as a carbon source at lower concentrations and as a stringent response trigger at higher concentrations. Nevertheless, the beneficial effect of methanol and optimal nitrogen concentration for PHB production was confirmed, providing a basis for future physiological analysis and conditions for process scale-up.

Keywords: methane, methanol, methanotrophs, polyhydroxybutyrate, methylocystis sp. rockwell, single carbon bioconversions

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Authors: Fariha Akhter Chowdhury, Mohammad Nurul Islam, Anamika Saha, Sabrina Mahboob, Abu Syed Md. Mosaddek, Md. Omar Faruque, Most. Fahmida Begum, Rajib Bhattacharjee

Abstract:

Urinary tract infection (UTI) is one of the most common infectious diseases in Bangladesh where Escherichia coli is the prevalent organism and responsible for most of the infections. Lipopolysaccharide (LPS) is known to act as a major virulence factor of E. coli. The present study aimed to purify, extract and visualize LPS of E. coli clinical isolates from urine samples of patients with UTI. The E. coli strain was isolated from the urine samples of 10 patients with UTI and then the antibiotic sensitivity pattern of the isolates was determined. The purification of LPS was carried out using the hot aqueous-phenol method and separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, which was directly stained using the modified silver staining method and Coomassie blue. The silver-stained gel demonstrated both smooth and rough type LPS by showing trail-like band patterns with the presence and lacking O-antigen region, respectively. Coomassie blue staining showed no band assuring the absence of any contaminating protein. Our successful extraction of purified LPS from E. coli isolates of UTI patients’ urine samples can be an important step to understand the UTI disease conditions.

Keywords: Escherichia coli, electrophoresis, polyacrylamide gel, silver staining, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE)

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Authors: H. Nabahat, E. Amiri, F. AzaditalabDavoudabadi, N. Zaeri

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Tooth decay is one of the most common forms of oral and dental illness in the world, which causes huge costs of treatment, especially in high-risk groups such as people with oral dry mouth, prevention and control of it are very important. The use of traditional treatments such as extraction of drugs from medicinal plants is of paramount importance to Iran and the international community as well. The present study was conducted with the aim of investigating the antibacterial effect of the extract of Salvia officinalis and Mentha pulegium, which are the most commonly used drugs in the treatment of oral and teeth bacterial (Streptococcus mutant, Lactobacillus rhamnosis, and Actinomyces viscosis) in vitro method. In this experimental study, two herbs of Salvia and Mentha were prepared by maceration of hydroalcoholic extract, and the antibacterial effect was evaluated by broth macro dilution on streptococcal mutagen bacteria, lactobacillus rhamnosis, and viscose actinomycosis. The results were analyzed by the Whitney Mann test (P > 0.05). The results showed that the minimum inhibitory concentration (MIC) of the salmonella extract for Streptococcus mutan were 6.25 and 12.5 μg/ml, respectively, for lactobacillus of 1.56 and 3.12 μg/ml, respectively, and for actinomycosis viscose, The order of 12.5 and 100 μg/ml was obtained. As a result, broth macro dilution showed that both extracts of Salvia and Mentha had an inhibitory effect on all three species of bacteria. This effect for Salvia was significantly (P < 0.05) more than Mentha and was within the concentration range of both the extracts and had a bactericidal effect on all three bacteria.

Keywords: antibacterial effect, dental bacteria, herbal extracts , salvia officinalis, mentha pulegium

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Authors: Negar Zaheddoust, Negin Zaheddoust, Abbas Asoudeh-Fard

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Probiotic bacteria have been employed as a novel and less side-effect strategy for anticancer therapy. Since the oral cavity is a host for probiotic and pathogen bacteria to colonize, more investigation is needed to evaluate the effectiveness of this novel adjunctive treatment for oral cancer. We considered Lactobacillus plantarum as a probiotic and Streptococcus mutans as a pathogen bacterium in our study. The aim of this study is to examine the effect of Lactobacillus plantarum and Streptococcus mutans on Casp3, AKT / PTEN, and MAPK signaling pathway, which is involved in apoptosis or survival of oral cancer KB cells. On the other hand, to study the effects of these bacteria on normal cells, we used HUVEC cells. The KB and HUVEC cell lines were co-cultured with Lactobacillus plantarum and Streptococcus mutans isolated from traditional Iranian dairy and dental plaque, respectively. The growth-inhibitory effects of these two bacteria on KB and HUVEC cells were determined by (3-(4, 5-dimethylthiazolyl-2)-2,5diphenyltetrazolium bromide) MTT assay. MTT results demonstrated that the proliferation of KB cells was affected in a time, dose, and strain-dependent manner. In the following, the examination of induced apoptosis or necrosis in co-cultured KB cells with the best IC50 concentration of the Lactobacillus plantarum and Streptococcus mutans will be analyzed by FACS flow cytometry, and the changes in gene expression of Casp3, AKT / PTEN, MAPK genes will be evaluated using real-time polymerase chain reaction.

Keywords: cancer therapy, induced apoptosis, oral cancer, probiotics

Procedia PDF Downloads 223

Authors: Rashad R. Al-Hindi

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The aim of this study was to isolate and identify lactic acid bacteria and evaluate their therapeutic and food preservation importance. Ninety-three suspected lactic acid bacteria (LAB) were isolated from thirteen different raw and fermented milk of indigenous sources in the Kingdom of Saudi Arabia. The identification of forty-six selected LAB strains and genetic relatedness were performed based on 16S rDNA gene sequence comparison. The LAB counts in certain samples were higher under microaerobic than anaerobic conditions. The identified LAB belonged to genera Enterococcus (16 strains), Lactobacillus (9 strains), Weissella (10 strains), Streptococcus (8 strains) and Lactococcus (3 strains). Phylogenetic tree generated from the full-length (~1.6 kb) sequences confirmed previous findings. Utilization of shorter 16S rDNA sequences (~1.0 kb) also discriminated among strains of which V2 region was the most effective. None of the strains exhibited resistance to clinically relevant antibiotics or undesirable hemolytic activity, while they differed in other probiotic characteristics, e.g., tolerance to acidic pH, resistance to bile salt, and antibacterial activity. In conclusion, the isolates Lactobacillus casei MSJ1, Lactobacillus casei Dwan5, Lactobacillus plantarum EyLan2 and Enterococcus faecium Gail-BawZir8 are likely the best probiotic LAB and we speculate that studying the synergistic effects of bacterial combinations might result in the occurrence of more effective probiotic potential. We argue that the raw and fermented milk of animals hosted in Saudi Arabia, especially stirred yogurt (Laban) made from camel milk, are rich in LAB with promising probiotics potential.

Keywords: fermented foods, lactic acid bacteria, probiotics, Saudi Arabia

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Authors: W. Mohammed Saeed, A. J. Mcbain, S. M. Cruickshank, C. A. O’Neill

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In the gut, probiotics have been shown to protect epithelial cells from pathogenic bacteria through a number of mechanisms: 1-Increasing epithelial barrier function, 2-Modulation of the immune response especially innate immune response, 3-Inhibition of pathogen adherence and down regulation of virulence factors. Since probiotics have positive impacts on the gut, their potential effects on other body tissues, such as skin have begun to be investigated. The purpose of this project is to characterize the potential of probiotic bacteria lysate as therapeutic agent for preventing or reducing the S. aureus infection. Normal human primary keratinocytes (KCs) were exposed to S. aureus (106/ml) in the presence or absence of L. rhamnosus GG lysate (extracted from 108cfu/ml). The viability of the KCs was measured after 24 hours using a trypan blue exclusion assay. When KCs were treated with S aureus alone, only 25% of the KCs remained viable at 24 hours post infection. However, in the presence of L. rhamnosus GG lysate the viability of pathogen infected KCs increased to 58% (p=0.008, n=3). Furthermore, when KCs co-exposed, pre- exposed or post-exposed to L. rhamnosus GG lysate, the viability of the KCs increased to ≈60%, the L. rhamnosus GG lysate was afforded equal protection in different conditions. These data suggests that two possible separate mechanisms are involved in the protective effects of L. rhamnosus GG such as reducing S. aureus growth, or inhibiting of pathogenic adhesion. Interestingly, a lysate of L rhamnosus GG provided significant reduction in S. aureus growth and adhesion of S. aureus that being viable following 24 hours incubation with S aureus. Therefore, a series of Liquid Chromatography (RP-LC) methods were adopted to partially purify the lysate in combination with functional assays to elucidate in which fractions the efficacious molecules were contained. In addition, the Mass Spectrometry-based protein sequencing was used to identify putative proteins in the fractions. The data presented from purification process demonstrated that L. rhamnosus GG lysate has the potential to protect keratinocytes from the toxic effects of the skin pathogen, S. aureus. Three potential mechanisms were identified: inhibition of pathogen growth; competitive exclusion; and displacement of the pathogen from keratinocyte binding sites. In this study, ‘moonlight’ proteins were identified in the current study’s MS/MS data for L. rhamnosus GG lysate, which could elucidate the ability of lysate in the competitive exclusion and displacement of S. aureus from keratinocyte binding sites. Taken together, it can be speculated that L. rhamnosus GG lysate utilizes different mechanisms to protect keratinocytes from S. aureus toxicity. The present study indicates that the proteinaceous substances are involved in anti-adhesion activity. This is achieved by displacing the pathogen and preventing the severity of pathogen infection and the moonlight proteins might be involved in inhibiting the adhesion of pathogens.

Keywords: lysate, fractions, adhesion, L. rhamnosus GG, S. aureus toxicity

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Authors: Tsige Reda

Abstract:

Essential oil of Thymus vulgaris was extracted by means of hydro-distillation. This study was done to investigate the chemical composition, antibacterial and antioxidant activities. The chemical composition of the essential oils was determined using gas chromatography coupled to mass spectroscopy (GC-MS). Using disc diffusion assay the antibacterial activity was assessed on one Gram-positive bacteria and one Gram-negative bacteria. The percentage oil yield of the essential oil was found to be 0.97 ± 0.08% (w/w) with yellow color. The physicochemical constants of the oil were also noted. The phytochemical screening of the plant extract revealed the presence of tannins, saponins, phenol, flavonoids, terpenoids, steroids and alkaloids. A total of 18 chemical constituents were identified by Gas Chromatography-Mass Spectroscopy analysis representing 100% of the total essential oil of Thymus vulgaris, with thymol (31.977%), o-cymene (29.992%), and carvacrol (14.541%). Previous studies have revealed that the thymol, o-cymen and carvacrol components of Thymus vulgaris are responsible for their biological activities. Thymus vulgaris have been used traditionally to treat a wide variety of infections. Based on the extensive use and lack of scientific evidence, a study was embarked upon to determine its bioactivity. The essential oil of Thymus vulgaris leaves exhibited higher activity towards the Gram-positive bacteria (Staphylococcus aurous) than the Gram-negative bacteria (Escherichia coli) and also has good antioxidant activity, and can be used medicinal and therapeutic applications. This activity may be due to the high amount of thymol, o-cymen and carvacrol.

Keywords: hydro-distillation, Thymus vulgaris, essential oil composition, phytochemical screening, physicochemical constants, antioxidant activity, antibacterial activity

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Authors: M. E. Abalaka, S. Y. Daniyan, S. O. Adeyemo, D. Damisa

Abstract:

Gold nanoparticles (AuNPs) have gained increasing interest in recent times. This is greatly due to their special features, which include unusual optical and electronic properties, high stability and biological compatibility, controllable morphology and size dispersion, and easy surface functionalization. In typical synthesis, AuNPs were produced by reduction of gold salt AuCl4 in an appropriate solvent. A stabilizing agent was added to prevent the particles from aggregating. The antibacterial activity of different sizes of gold nanoparticles was investigated against Staphylococcus aureus, Salmonella typhi and Pseudomonas pneumonia using the disk diffusion method in a Müeller–Hinton Agar. The Au-NPs were effective against all bacteria tested. That the Au-NPs were successfully synthesized in suspension and were used to study the antibacterial activity of the two medicinal plants against some bacterial pathogens suggests that Au-NPs can be employed as an effective bacteria inhibitor and may be an effective tool in medical field. The study clearly showed that the Au-NPs exhibiting inhibition towards the tested pathogenic bacteria in vitro could have the same effects in vivo and thus may be useful in the medical field if well researched into.

Keywords: gold nanoparticles, Gomphrena celesioides, Prunus amygdalus, pathogens

Procedia PDF Downloads 287