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Bacterial metabarcoding analysis by 16S rDNA of five occurrences of mineral waters in Serbia (Torda, Slankamen Banja, Lomnički Kiseljak, Velika Vrbnica and Obrenovačka Banja) indicated the presence of a high percentage of the Proteobacteria phylum, followed by the Bacteroidetes phylum. The families Rhodobacteraceae, Burkholderiaceae, Pseudomonadaceae, Methylophilaceae and Moraxellaceae were the most dominant in the bacterial flora of the selected occurrences, whereas the most represented genera were Acinetobacter, Pseudorhodobacter, Pseudomonas, Limnohabitans, Massilia, Limnobacter and Methylotenera. The presence of coliform bacteria was not detected. Alpha diversity analysis revealed that Slankamen Banja and Lomnički Kiseljak were the richest of the selected occurrences, while the mineral waters of Torda, Velika Vrbnica and Obrenovačka Banja were characterized by similar diversity of bacterial communities determined by beta diversity analysis. Physical-chemical analysis revealed the value of total dissolved solids above 1 g/L, as well as elevated concentrations of some metals and non-metals. The research concluded that specific bacteria contribute to the development of biocorrosion and biofouling processes of water intake facilities. In addition, some of these bacteria might be potential indicators of the organic sources of pollution and/or biotechnological natural remediators in the treatment of contaminated waters. [ABSTRACT FROM AUTHOR]

European plum (Prunus domestica L.) is a significant commercial crop in Serbia in terms of total fruit production, and is traditionally processed into slivovitz brandy. The brown rot disease caused by Monilinia laxa drastically reduces plum yield almost every year. Fungal communities associated with leaves and fruits of four local Serbian plum cultivars (Požegača, Ranka, Čačanska Lepotica and Čačanska Rodna) were investigated in two phenological stages during early (May) and late (July) fruit maturation. Alpha diversity indices showed that fungal communities were heterogeneous and Beta diversity indicated that autochthonous fungal communities depended upon seasonal changes and the cultivars themselves. The phylum Ascomycota was the most abundant in all samples, with relative abundance (RA) between 46% in the Požegača cultivar (May) and 89% in the Lepotica cultivar (July). The most abundant genus for all plum cultivars in May was Aureobasidium , with RA from 19.27 to 33.69%, followed by Cryptococcus , with 4.8 to 48.80%. In July, besides Cryptococcus , different genera (Metschnikowia , Fusarium , and Hanseniaspora) were dominant on particular cultivars. Among all cultivable fungi, molecular identification of eleven M. laxa isolates from four plum cultivars was performed simultaneously. Bacterial isolates from the plum phyllosphere were tested for their potential antifungal activity against indigenous M. laxa isolates. The most potent antagonist P4/16_1, which significantly reduced mycelial growth of M. laxa , was identified as Pseudomonas synxantha. Further characterization of P4/16_1 revealed the production of volatile organic compounds and phenazine-1-carboxylic acid (PCA). Crude benzene extract of PCA exhibited 57–63% mycelial growth inhibition of M. laxa. LC/MS analysis of the crude extract confirmed the presence of phenazine derivatives amongst other compounds. Scanning electron microscopy revealed morpho-physiological changes in the hyphae of M. laxa isolates caused by the cell culture and the P. synxantha P4/16_1 crude benzene extract. This is the first report of antagonistic activity of P. synxantha against M. laxa induced by diffusible and volatile antifungal compounds, and it appears to be a promising candidate for further investigation for potential use as a biocontrol agent against brown rot-causing fungi. [ABSTRACT FROM AUTHOR]

Extensive employment of plant resins and propolis, as an antiseptic agents dating from ancient times in numerous cultures indicating that it may have antimicrobial and other biological properties. Resins from deciduous trees from the Populus and Salix genera, several fruit trees from the genus Prunus and a few other species were analyzed for their phenolic composition and antibacterial activity. Phenolic profiling of the plant resins was performed by high-performance thin-layer chromatography (HPTLC) and ultra-high-performance liquid chromatography (UHPLC) coupled with hybrid mass spectrometry. Antimicrobial activity against seven bacterial species was determined by minimum inhibitory concentration (MIC) assays and bioautography. The synergism, additivism, and antagonism of phenolic compounds were used to define the nature and type of interactions. Populus spp. showed higher amounts of p -hydroxybenzoic acid, p -coumaric acid, caffeic acid, chrysin, apigenin, quercetin, pinocembrin, pinobanksin and galangin, which confirmed the botanical origin of the orange and blue types of propolis. In addition, Gram-positive bacteria exhibited high susceptibility to poplar samples while being resistant to samples from other origins. Cherry bud samples had high amounts of naringenin and showed strong activity against Bacillus subtilis and Listeria monocytogenes . The combinations of tested phenolics showed mainly additive or indifferent effects. [ABSTRACT FROM AUTHOR]