Biosurfactants (BSs) are surface-active compounds produced by diverse microorganisms, including the genus Bacillus. These bioactive compounds possess biological activities such as antiadhesive, antimicrobial and antibiofilm effects that can lead to important applications in combating many infections. Based on these findings, we decided to investigate the antibiofilm activity of BSs from the marine Bacillus amyloliquefaciens against Staphylococcus aureus CCM 4223. Expression of biofilm-related genes was also evaluated using qRT-PCR. Isolated and partially purified BSs were identified and characterized by molecular tools and by UHPLC-DAD and MALDI-TOF/MS. Bacillus amyloliquefaciens 3/22, that exhibited surfactant activity evaluated by oil spreading assay, was characterized using the 16S rRNA sequencing method. Screening by PCR detected the presence of the sfp, srfAA, fenD and ituD genes, suggesting production of the lipopeptides (LPs) surfactin, fengycin and iturin. The above findings were further supported by the results of UHPLC-DAD and MALDI-TOF/MS. As quantified by the crystal violet method, the LPs significantly (p < 0.001) reduced biofilm formation of S. aureus in a dose-dependent manner and decreased expression of biofilm-related genes fnbA, fnbB, sortaseA and icaADBC operon. Data from our investigation indicate a promising therapeutic application for LPs isolated from B. amyloliquefaciens toward prevention of S. aureus biofilm infections.
The aim of this study was to identify beneficial bacteria with probiotic potential from kefir grains. The lactobacilli isolated from kefir grains were characterised as:
In this study we isolated and identified the lipopeptides produced by Bacillus amyloliquefaciens strains 1/6k and 4/9, which were isolated from Adriatic Sea. Lipopeptides belong to the family of cyclic biosurfactants representing a group of surface active compounds produced by various microorganisms. Studied Bacillus spp. strains were able to produce cyclic lipopeptides surfactin, iturin A and fengycin. The characterisation of lipopeptides was studied by various analytical techniques (high-performance liquid chromatography – HPLC and matrix-assisted laser desorption/ionization time-of-flight analysis for molecular mass determination – MALDI-TOF/MS). These methods confirmed co-production of three lipopeptides – surfactin, iturin A and fengycin by Bacillus amyloliquefaciens.
The aim of this work was to monitor the potential antibiofilm properties of biosurfactants (BS) isolated from Bacillus amyloliquefaciens 3/22 against biofilm formation of the indicator strain Staphylococcus aureus CCM 4223. In this work, the effect of BS
Colonization of the oral cavity begins immediately after birth, however, only some microorganisms are capable of exerting their action in the oral environment. A wide range of microorganisms is found in the oral cavity, whether commensal, facultative pathogenic or obligatory pathogenic. Their mutual ratios and numbers are considerably affected by probiotic bacteria of the oral microbiota, particularly by their products, such as bacteriocins. The probiotics most frequently living in the oral cavity include Lactobacillus reuteri, Streptococcus salivarius and Bacillus coagulans. This study is focused on oral probiotics which could improve the health of the oral cavity and prevent development of dental carries. Basic techniques, which are necessary in research of oral microbiota that could be potentially beneficial in dental microbiology, are also presented. We recommended these techniques based on our experiences in this field. In this study we describe microbiological methods for obtaining of live bacterial strains in dental plaque or dental calculus, that are used for preparation of the bacterial strains´ collection and their storage possibilities for next testing. Study also describes two sensitive molecular methods usable for identification of these bacterial strains, the first with help of 16S rRNA and next blast n analysis based on consensus DNA sequences, and the second based on MALDI-TOF mass spectrometry. PCR methods for deeper characterization of selected bacterial strains e.g. pathogenic like Streptococcus mutans or potentially beneficial bacteria such as Str. salivarius and Lactobacillus spp. are also described. These methods are based on detection of genes coding production of bacteriocins or coding genes responsible for pathogenicity e.g. glucosyl or fructosyl transferaze genes. We also recommend the method for detection of hard cultivable spirochetes based on the morphological characteristics with help of VFQTOPF method and next by PCR methods used for detection of Treponema denticola in dental plaque samples.
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