Probiotic potential of Lactobacillus fermentum G-4 originating from the meconium of newborns

The present study was dedicated to determining probiotic potential of a human isolate G-4, originated from meconium. The isolate was identified using morphological, physiological and biochemical assays and molecular method based on 16S rRNA gene sequencing. In order to evaluate its probiotic properties in vitro tests were performed: the survival in simulated gastrointestinal conditions, adhesion to hexadecane, and antimicrobial activity. Safety aspects of the isolate were examined by testing toxicity, gastrointestinal tolerance and bacterial translocation in vivo, as well as hemolytic activity in vitro. The isolate G-4, identified as Lactobacillus fermentum, showed viability in artificial gastric and intestinal juice (low degree of cell viability reduction for 0.69 and 1.30 logCFU mL(-1) units, respectively), moderate adhesion to hexadecane (39 +/- 2.1 %), and antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serotype Abony and Clostridium sporogenes, due to production of lactic acid (9.80 g L-1). No signs of toxicity, bacterial translocation, hemolytic activity, were observed

Characterization of lactococci isolated from homemade kefir

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

Thermal stability and degradation of binuclear hexaaqua-bis(ethylenediamine)-(μ 2-pyromellitato)dinickel(II) tetrahydrate

Thermal degradation of ternary transition metal complex containing tetraanion of pyromellitic acid, pyr, and ethylenediamine, en, [Ni2(en)2(H2O)6(pyr)]·4H2O, 1, was investigated under non-isothermal conditions. The mechanism of thermal degradation, which occurs in three steps, was clarified by TG/DSC measurements in conjunction with FT-IR spectroscopy and XRPD analysis. The complexity of all degradation steps has been revealed using isoconversional methods. Dehydration comprises the loss of ten water molecules in a relatively narrow temperature interval, resulting in a very complicated reaction mechanism. In addition, density functional theory calculations have been applied for better understanding of dehydration. The second degradation step, related to loss of en, was separated into two single-step processes with Fraser–Suzuki function. The obtained individual steps were described by Johnson–Mehl–Avrami A2 model and Šesták–Berggren model, respectively. Validation of the proposed kinetic triplets for individual steps was performed using master plot and Pérez-Maqueda criteria. The third degradation step is related to the fragmentation of pyr ion most likely followed with the release of a number of gaseous products

POST-TRANSLATIONAL REGULATION OF THE rpoS AND psrA GENES IN Pseudomonas putida WCS358: THE ROLE OF ClpXP PROTEASE

Abstract — 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 degradеd by ClpXP in the early exponential phase of growth. The оbtained results demonstrate a role for ClpXP protease in post-translational regulation of proteins encoded by the rpoS and psrA genes in Pseudomonas spp

DOI:10.2298/ABS0701013K CHARACTERIZATION OF LACTOCOCCI ISOLATED FROM HOMEMADE KEFIR

Abstract – 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

DNA architecture and transcriptional regulation of the Escherichia coli penicillin amidase (pac) gene

The transcriptional regulation of Escherichia coli ATCC11105 penicillin amidase (pac) gene was studied by modifying DNA sequences responsible For promoter activation by cyclic AMP receptor protein (CRP). The nucleotide sequence of the 5'-flanking region of the pac gene contains putative tandem CRP binding sites positioned at -69/-70 and at -111/-112 with respect to the transcriptional start site. Our results obtained with either point mutations or insertion or deletion mutants (each of which rotated the helix structure at the CRP binding site one-half turn) showed significant decrease of penicillin amidase (PA) activity, suggesting the CRP as a major activator. In this study, the evidence fur the importance of spacing between tandem binding sites for CRP as well as for their location related to the promoter core sequence has been provided. Involvement of integration host factor (IHF) as an additional regulatory protein in the pac gene transcription regulation was also analyzed. It is shown that activation of the pac gene transcription is elevated by IHF

Lactococcus lactis and Lactobacillus salivarius differently modulate early immunological response of Wistar rats co-administered with Listeria monocytogenes

In the light of the increasing resistance of bacterial pathogens to antibiotics, one of the main global strategies in applied science is development of alternative treatments, which would be safe both for the host and from the environmental perspective. Accordingly, the aim of this study was to test whether two lactic acid bacteria (LAB) strains, Lactococcus lactis BGBU1-4 and Lactobacillus salivarius BGHO1, could be applied as safe supplements for Listeria infection. Two major research objectives were set: to compare the effects of BGBU1-4 and BGHO1 on early immune response in gut tissue of Wistar rats co-administered with Listeria monocytogenes ATCC19111 and next, to test how this applies to their usage as therapeutics in acute ATCC19111 infection. Intestinal villi (IV), Peyer's patches (PP) and mesenteric lymph nodes (MLN) were used for the analysis. The results showed that BGHO1 increased the mRNA expression of innate immune markers CD14, interleukin (IL)-1 beta and tumour necrosis factor (TNF)-alpha in PP and IV, and, in parallel, caused a decrease of listeriolysin O (LLO) mRNA expression in same tissues. In MLN of BGHO1 treated rats, LLO expression was increased, along with an increase of the expression of OX-62 mRNA and CD69, pointing to the activation of adaptive immunity. On the other hand, in BGBU1-4 treated rats, there was no reduction of LLO mRNA expression and no induction of innate immunity markers in intestinal tissue. Additionally, CD14 and IL-1 beta, as well as LLO, but not OX-62 mRNA and CD69 expression, were elevated in MLN of BGBU1-4 treated rats. However, when applied therapeutically, both, BGBU1-4 and BGHO1, lowered Listeria count in spleens of infected rats. Our results not only reveal the potential of LAB to ameliorate Listeria infections, but suggest different immunological effects of two different LAB strains, both of which could be effective in Listeria elimination

Thermally induced structural transformations of multicomponent Fe72Cu1V4Si15B8 alloy

Thermally induced structural transformations of Fe72Cu1V4Si15B8alloy were examined. Thermal analysis revealed multistep structural stabilization process starting at around 470oC, manifested by two complex exothermic DTA peaks, which were deconvoluted. Microstructure of the as-prepared and thermally treated alloy was studied using XRD. Kinetic triplets of individual steps were determined and further checked by comparing simulated and experimental DTA curves.Physical chemistry 2016 : 13th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-30 September 201

Current state and prospects of biotechnology in Central and Eastern European countries. Part II: new and preaccession EU countries(CRO, RO, B&H, SRB)

Innovation holds the potential for economic prosperity. Biotechnology (BT) has proved to be a viable vehicle for the development and utilization of technologies, which has brought not only advances to society, but also career opportunities to nation-states that have enabling conditions. In this review, we assess the current state of BT-related activities within selected new and preaccession EU countries (NPA) of CEE region namely Croatia, Romania, Bosnia and Herzegovina and Serbia, examining educational programs, research activity, enterprises, and the financing systems. The field of BT covers a broad area of activities, including medical, food and agriculture, aquaculture or marine, environmental, biofuels, bioinformatics, and many others. Under the European Commission (EC), member-states are to set their Research and Innovation Strategies for Smart Specialization (RIS3), to identify priorities or strengths in order to develop knowledge intensive economies. As the four countries highlighted in this review are in the early stages of implementing RIS3 or have not yet fully formulated, it presents an opportunity to learn from the successes and failures of those that have already received major structural funds from the EC. A critical point will be the ability of the public and private sectors' actors to align, in the implementation of RIS3 as new investment instruments emerge, and to concentrate efforts on a few select target goals, rather than distribute funding widely without respect to a long-term vision