Dynamics of sodium dodecyl sulfate utilization andantibiotic susceptibility of strain Pseudomonas sp. ATCC19151

Poznato je da soj Pseudomonas sp. ATCC19151 poseduje gen koji kodira Potencijalnu alkilsulfatazu. U ovom radu analizirana je sposobnost rasta ovog soja u minimalnom medijum usa različitim koncentracijama natrijum dodecilsulfata (0.5, 0.75 i 1 %) kao jedinim izvorom ugljenika. Pokazano je da Pseudomonas sp. ATCC19151 ispoljava najbolji rast uminimalnom medijumusa 0.5 % natrijum dodecil sulfata, te je stoga ova koncentracija uzeta kao optimalna za testiranje dinamike korišćenja natrijum dodecil sulfata tokom različitih faza rasta. Dinamika korišćenja natrijum dodecil sulfata podudarala se sa rastom kulture. Pored toga u cilju detaljnije karakterizacije soja, analizirana je i osetljivost Pseudomonas sp. ATCC19151 na antibiotike. Pokazano je da je analizirani soj rezistentan na šest (ampicilin, tetraciklin, hloramfenikol, tobramicin, nalidiksičnukiselinui gentamicin) od devet analiziranih antibiotika.Pseudomonas sp. ATCC19151 harbors a gene encoding a putative alkylsulfatase (sdsA). Here we report a growth ability of this strain in minimal media containing 0.5, 0.75, and 1% sodium dodecyl sulfate as the sole carbon source. The most prominent growth was detected for the minimal medium with 0.5% SDS, so this concentration of SDS was used to monitor Pseudomonas sp. ATCC19151 SDS biodegradation dynamics. Bacterial growth coincided with the disappearance of SDS. Antibiotic susceptibility was tested as well. Pseudomonas sp. ATCC19151 was resistant to six out of nine tested antibiotics, including ampicillin, tetracycline, chloramphenicol, tobramycin, nalidixic acid, and gentamycin

Post-translational regulation of the RpoS and PsrA genes in pseudomonas putida WCS358: The role of ClpXP protease

RpoS i PsrA proteini su ključni transkripcioni regulatori koji se kod pseudomonada aktiviraju u odgovoru na stacionarnu fazu rasta. Cilj ove studije bio je utvrđivanje uloge ClpXP (ATP zavisna serin proteaza) u stabilnosti RpoS i PsrA proteina tokom različitih faza rasta u Pseudomonas putida WCS358. "Western blot" analiza proteinskih ekstrakata P. putida WCS358 i P. putida WCS358 clpX::Km iz rane eksponencijalne, Kasne eksponencijalne i stacionarne faze rasta, sa antitelima na RpoS i PsrA, pokazala je da ClpXP degraduje RpoS i PsrA u ranoj eksponencijalnoj fazi rasta.The RpoS and PsrA proteins are key transcriptional regulators that are activated in response to the stationary phase of growth in pseudomonads. This study was designed to establish whether ClpXP (ATP-dependent serine protease) regulates levels of RpoS and PsrA in Pseudomonas putida WCS358. Western blot analysis of P. putida WCS358 protein extracts from the early exponentianl, late exponential, and stationary phases of growth with antibodies against RpoS and PsrA revealed that these proteins are degraded by ClpXP in the early exponential phase of growth. The obtained results demonstrate a role for ClpXP protease in post-translational regulation of proteins encoded by the rpoS and psrA genes in Pseudomonas spp

Characterization of lactococci isolated from homemade kefir

Pet izolata laktokoka proizvođača bakteriocina izolovanih iz kefira pripremljenog na tradicionalan način determinisano je kao Lactococcus lactis subsp. lactis. Analizirani izolati poseduju različite plazmidne profile i među njima nije detektovana uzajamna antimikrobna aktivnost. Takođe prirodni izolat BGKF26 je rezistentan na aktivnost soja NP45, proizvođača nizina. Eksperimenti čišćenja plazmida pokazali su da se geni _a sintezu bakteriocina i proteinaza nalaze na različitim genetičkim elementima, osim kod izolata BGKF26. Sinteza analiziranih bakteriocina zavisi od koncentracije kazitona ili triptona u medijumu. Više koncentracije kazitona ili triptona indukuju bakteriocinsku aktivnost. Hibridizacioni eksperimenti su pokazali da su analizirani bakteriocini najverovatnije slični laktokokcinima.Five bacteriocin-producing lactococci isolates from traditionally prepared kefir were determined as Lactococcus lactis subsp. lactis. The analyzed isolates showed different plasmid profiles and no cross inhibition between them was detected. Moreover, natural isolate BGKF26 was resistant to the antimicrobial activity of nisin producing strain NP45. Plasmid curing experiments revealed that the genes encoding bacteriocin and proteinase production are located on separate genetic elements, except in BGKF26. Production of the tested bacteriocins depends on the concentration of casitone or triptone in the medium. Higher concentrations of casitone or triptone induce bacteriocin activity. Our DNA-DNA hybridization analyses suggest that the analyzed antimicrobial compounds probably are lactococcin-like bacteriocins

Effect of methionine and cysteine deprivation on growth of different natural isolates of Lactobacillus spp. in chemically defined media

Cilj ovog rada je bio da se utvrdi sposobnost prirodnih izolata laktobacila,izolovanih iz različitih ekoloških niša da rastu u hemijski definisanom medijumu sa ili bez prisustva aminokiselina koje sadrže sumpor, metionin i/ili cistein. Dobijeni rezultati su pokazali da je esencijalna aminokiselina za rast izolata L. paracasei subsp. paracasei BGHN14 i BGSJ2-8 cistein, dok je za izolate BGHN40, BGCG31, BGHV54T, koji pripadaju vrsti L. plantarum-metionin. Metionin je esencijalna aminokiselina za rast soja L. rhamnosus BGHV58T. Ostali analizirani sojevi,kao što su L. plantarum BGSJ3-18,BGZB19,BGHV52Ta i BGHV43T za svoj rast zahtevaju prisustvo obe aminokiseline u medijumu.The purpose of this study was to determine the ability of natural isolates of lactobacilli from different ecological niches to grow in a chemically defined medium in the presence or absence of sulphur-containing amino acids, methionine and/or cysteine. The obtained results indicate that cysteine is essential for growth of L. paracasei subsp. paracasei BGHN14 and BGSJ2-8, while methionine is essential for isolates BGHN40, BGCG31, and BGHV54T of the species L. plantarum. Methionine is also essential for growth of L. rhamnosus BGHV58T. Other analyzed strains, such as L. plantarum BGSJ3-18, BGZB19, BGHV52Ta, and BGHV43T, require the presence of both amino acids for their growth

Dominant lactic acid bacteria in artisanal Pirot cheeses of different ripening period

U ovom radu su ispitivana dva sira od svežeg kravljeg mleka različitog perioda zrenja. Sirevi su uzeti iz seoskog domaćinstva u regionu Stare Planine, a proizvedeni su bez dodatka starter kulture. Iz oba sira je izolovano ukupno 106 sojeva bakterija mlečne kiseline. Sojevi su testirani klasičnim fiziološkim i API 50 CH testovima. Takođe je ispitivana proteolitička i antimikrobna aktivnost. Identifikacija bakterija mlečne kiseline je rađena rep-PCR analizom sa (GTG)5 prajmerom. Osam vrsta bakterije mlečne kiseline je izolavano iz sira BGPT9 starog četiri dana (Lactobacillus plantarum, Lactobacillus paracasei subsp. paracasei, Lactobacillus delbrueckii, Lactobacillus brevis, Enterococcus faecium, Enterococcus faecalis, Enterococcus durans i Leuconostoc garlicum), dok su u siru BGPT10 starom osam meseci bile prisutne samo dve vrste (Lactobacillus plantarum i Enterococcus faecium). Proteolitičku aktivnost je pokazalo 30 izolata iz sira BGPT9, uglavnom enterokoke. Samo jedan izolat iz sira BGPT10 (koji je pripadao vrsti Lactobacillus plantarum) je posedovao delimičnu sposobnost da hidrolizuje β- kazein. Sedam enterokoka iz sira BGPT9 i četiri enterokoke iz sira BGPT10 je proizvodilo antimikrobne substance.In this study two raw cow's milk cheeses of a different ripening period were examined. The cheeses were taken from a country household in the region of mountain Stara Planina and manufactured without adding of starter culture. A total 106 lactic acid bacteria (LAB) strains were isolated from both cheeses. They are tested by classical physiological tests as well as by API 50 CH tests. Proteolytic and antimicrobial activities were done too. Identification of LAB isolates was done by repetitive extragenic palindromic-polimerase chain reaction (rep-PCR) with (GTG)5 primer. The LAB isolates from cheese BGPT9 (four days old) belonged to the eight species of LAB (Lactobacillus plantarum, Lactobacillus paracasei subsp. paracasei, Lactobacillus delbrueckii, Lactobacillus brevis, Enterococcus faecium, Enterococcus faecalis, Enterococcus durans and Leuconostoc garlicum), while in the BGPT10 cheese (eight months old) only two species were present (Lactobacillus plantarum and Enterococcus faecium). Proteolytic activity showed 30 LAB from BGPT9 cheese, mainly enterococci. From BGPT10 cheese only one isolate (which belonged to the Lactobacillus plantarum species) possessed partial ability to hydrolyze β-casein. Seven enterococci from BGPT9 cheese and four enterococci from BGPT10 cheese produced antimicrobial compounds

Cloning and expression of a novel lactococcal aggregation factor from Lactococcus lactis subsp. lactis BGKP1

<p>Abstract</p> <p>Background</p> <p>Aggregation may play a main role in the adhesion of bacteria to the gastrointestinal epithelium and their colonization ability, as well as in probiotic effects through co-aggregation with intestinal pathogens and their subsequent removal. The aggregation phenomenon in lactococci is directly associated with the sex factor and lactose plasmid co-integration event or duplication of the cell wall spanning (CWS) domain of PrtP proteinase.</p> <p>Results</p> <p><it>Lactococcus lactis </it>subsp. <it>lactis </it>BGKP1 was isolated from artisanal semi-hard homemade cheese and selected due to its strong auto-aggregation phenotype. Subsequently, non-aggregating derivative (Agg^-) of BGKP1, designated as BGKP1-20, was isolated, too. Comparative analysis of cell surface proteins of BGKP1 and derivative BGKP1-20 revealed a protein of approximately 200 kDa only in the parental strain BGKP1. The gene involved in aggregation (<it>aggL</it>) was mapped on plasmid pKP1 (16.2 kb), cloned and expressed in homologous and heterologous lactococci and enterococci. This novel lactococcal aggregation protein was shown to be sufficient for cell aggregation in all tested hosts. In addition to the <it>aggL </it>gene, six more ORFs involved in replication (<it>repB </it>and <it>repX</it>), restriction and modification (<it>hsdS</it>), transposition (<it>tnp</it>) and possible interaction with mucin (<it>mbpL</it>) were also located on plasmid pKP1.</p> <p>Conclusion</p> <p>AggL is a new protein belonging to the collagen-binding superfamily of proteins and is sufficient for cell aggregation in lactococci.</p

Characterisation of natural isolate Lactococcus lactis subsp. lactis BGIS29, a strain producing bacteriocin IS29 and cell wall-associated proteinase

Soj Lactococcus lactis subsp. lactis BGIS29 je prirodni izolat iz sira proizvedenog u domaćinstvu koji proizvodi bakteriocin IS29 i proteinazu PI-tipa. Rezultati dobijeni biohemijskom karakterizacijom bakteriocina IS29 sugerišu da on pripada klasi II bakteriocina. DNK-DNK hibridizacija i PFGE analiza su pokazali da su geni za proteinazu i proizvodnju bakteriocina locirani na različitim genetičkim elem- entima. Proizvodila proteinaze coja BGIS29 i bakteriocina IS29 zavise od koncentracije kazitona u medijumu za rast bakterija. Veće koncentracije kazitona imaju inhibitorni efekat na aktivnost proteinaze. Nasuprot tome, proizvodila bakteriocina IS29 je izraženija u medijumu koji sadrži veće koncentracije kazitona.Strain Lactacoccus lactis subsp. lactis BGIS29, a natural isolate from homemade cheese produces the bacteriocin IS29 and the Pi-type proteinase. The results obtained by biochemical characterization of bacteriocin IS29 suggest that it belongs to class II of bacteriocins. The DNA-DNA hybridization and PFGE analysis showed that the genes for proteinase and bacteriocin production are located on separate genetic elements. Production of the proteinase of BGIS29 and the bacteriocin IS29 depend on the concentration of casitone in medium. Higher concentrations of casitone expressed an inhibitory effect on the proteinase activity. In contrast, production of bacteriocin IS29 was more pronounced in medium containing high casitone concentrations

Technological and probiotic potential of BGRA43 a natural isolate of Lactobacillus helveticus

Lactobacillus helveticus BGRA43 is a human intestinal isolate showing antimicrobial activity, amongst others, against Yersinia enterocolitica, Shigella sonnei, Shigella flexneri, and Streptococcus pneumoniae. BGRA43 produces PrtH proteinase with proteolytic activity on both casein and beta-lactoglobulin (BLG). BGRA43 is able to reduce the allergenicity of BLG. Bioactive peptides released in BGRA43 fermented milk are potent modulators of innate immunity by modulating the production of proinflammatory cytokines IL-6 and TNF-alpha. BGRA43 is able to survive in simulated gastric and intestinal conditions. The growth of BGRA43 in milk results in a fast acidification lowering the milk pH to 4.53 generating mild, homogeneous, and viscous yogurt-like product. The strain BGRA43 grows suitably in pure cow or goat's milk as well as in milk containing inulin or nutrim even when they are used as the sole carbon source. It is suggested that strain BGRA43 could be used as a single-strain culture for the preparation of yogurt-like products from bovine or caprine milk. Overall, L. helveticus BGRA43 could be considered as a potential probiotic candidate with appropriate technological properties attractive for the dairy industry

Temperature, pH and Trimethoprim-Sulfamethoxazole Are Potent Inhibitors of Biofilm Formation by Stenotrophomonas maltophilia Clinical Isolates

Stenotrophomonas maltophilia, an opportunistic pathogen usually connected with healthcare-associated infections, is an environmental bacterium. Intrinsic resistance to multiple antibiotics, with different virulence determinants in the last decade classified this bacterium in the group of global multiple drug resistant (MDR) organism. S. maltophilia clinical isolates, were collected from tertiary care pediatric hospital in Belgrade, Serbia to investigate influence of different factors on biofilm formation, kinetics of biofilm formation for strong biofilm producers and effect of trimethoprim-sulfamethoxazole (TMP/SMX) on formed biofilm. Most of the isolates (89.8%) were able to form a biofilm. Analysis of biofilm formation in different growth conditions showed that changing of temeperature and pH had the stronggest effect on biofilm formation almost equally in group of cystic fibrosis (CF) and non-CF strains. TMP/SMX in concentration of 50 mu g/ml reduced completely 24 h old biofilms while concentration of 25 mu g/ml effects formed biofilms in a strain dependent manner. Among strains able to form strong biofilm CF isolates formed biofilm slower than non-CF isolates, while shaking conditions did not affect biofilm formation. Swimming motility was detected in both CF and non-CF isolates, however more motile strain formed stronger biofilms. This study suggests that temperature, pH and TMP/SMX had the strongest influence on biofilm formation in analyzed collection of S. maltophilia. A positive correlation between motility and strength of formed biofilm was demonstrated