1,721,006 research outputs found
Practical importance of tetracycline resistance in Lactobacillus plantarum used as silage inoculant
No full textA strain of Lactobacillus plantarum was selected for its peculiar tetracycline resistance as inoculants for maize silage. This character was linked to a 5.8 Mdal plasmid as demonstrated by curing method. Tetracycline resistance resulted in an efficient marker to demonstrated the colonization ability of L. plantarum introduced in a laboratory model maize silage
Partial characterization and plasmid linkage of a non-proteinaceus antimicrobial compound in a Lactobacillus casei of vegetable origin
No full textLactobacillus casei IMPC LC34 of vegetable origin produces a non- proteinaceous inhibitory compound with a broad spectrum of activity towards Gram-positive and Gram-negative bacteria, including pathogens. The active substance, mainly produced in the stationary phase of growth, is insensitive to proteolytic enzymes, lipase and catalase, and is stable at 121 °C for 30 min. The inhibitory activity was detected either at 8 °C or at 37 °C. The active compound does not contain glucidic groups, is inactivated by Na- metaperiodate, and its molecular mass is between 2000 and 5000 Da. Plasmid curing experiments showed that both antimicrobial compound immunity and production determinants were encoded by an 8.8 kbp plasmid. The effectiveness of the active agent was verified on ready-to-use vegetables, using either the Lact. casei strain or its culture supernatant fluid as inoculant, compared with cured clone. The application potential of the Lact. casei strain or its culture supernatant fluid for assuring the microbiological safety of ready- to-use vegetables is discussed
Potential of Lactobacillus casei, culture permeate and lactic acid to control microorganisms in ready-to-use-vegetables
No full textThe effects of various treatments (i.e., the addition of a strain of Lactobacillus that produces antimicrobial agents, Lactobacillus casei IMPC LC34, its sterile permeate, and 0.5 or 1% lactic acid) on the growth of microorganisms associated with ready-to-use mixed salad vegetables were compared during refrigerated (8°C) storage. The addition of 3% culture permeate to mixed salads reduced the total mesophilic bacteria counts from 6 to 1 log CFU/g, and suppressed coliforms, enterococci, and Aeromonas hydrophila after 6 days of storage at 8°C. A similar effect was shown when the L. casei culture was inoculated in the vegetables. One percent lactic acid had a bacteriostatic effect on the bacterial groups examined, except for total and fecal coliforms, which were reduced by about 2 and 1 log unit, respectively, while 0.5% lactic acid did not affect the indigenous microflora of the vegetables. The potential of these new hurdles to prevent the growth of spoilage and pathogenic bacteria in ready-to-use salad vegetables is suggested
Tracing Pediococcus acidilactici in ensiled maize by plasmid-encoded erythromycin resistance
No full textCuring experiments undertaken on Pediococcus acidilactici strain S364, isolated from maize silage, revealed a linkage between a resident 40 MD plasmid and resistance to erythromycin, oleandomycin and tylosin. The possibility of using erythromycin resistance to monitor the fate of this strain in a model ensiling system was also demonstrated
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Inhibitory effect of selected lactic acid bacteria on microflora associated with ready-to-use vegetables
No full textThe addition of selected lactic acid bacteria strains had a remarkable inhibitory effect on the growth dynamics of microflora associated with ready-to-use vegetables, during refrigerated storage. In particular, coliforms and enterococci were strongly reduced or eliminated from the products from the third day of storage. Lactobacillus casei strains proved more effective than pediococci. The use of lactic cultures able to produce bacteriocins and to grow at low temperatures could be a useful tool to preserve fresh vegetables and to ensure their microbiological safety
Application of antimicrobial-producing lactic acid bacteria to control pathogens in ready-to-use vegetables
No full textFive psychrotrophic strains of lactic acid bacteria (Lactobacillus casei, Lact. plantarum and Pediococcus spp.) were isolated from 22 samples of commercial salads. These strains were shown to inhibit Aeromonas hydrophila, Listeria monocytogenes, Salmonella typhimurium and Staphylococcus aureus on MRS agar, in salads and in juice prepared from vegetable salads. Lactobacillus casei IMPCLC34 was most effective in reducing total mesophilic bacteria and the coliform group; Aer. hydrophila, Salm. typhimurium and Staph. aureus disappeared after 6 d of storage, while the counts for L. monocytogenes remained constant. The potential application of antimicrobial- producing lactic acid bacteria as biopreservatives of ready-to-use vegetables is suggested
Lactic acid bacteria in ensiled high-moisture corn grain: Physiological and genetic characterization
No full textOf 335 lactic acid bacteria, isolated from high-moisture corn grain, 212 were checked for their physiological characteristics and 59 representative strains were chosen for DNA-DNA hybridization. All the homofermentative lactobacilli tested were highly related to the type strain of Lactobacillus plantarum. The pediococci isolated were allotted to Pediococcus pentosaceus. Of the heterofermentative lactic acid bacteria the cocci were classified as Leuconostoc paramesenteroides, the lactobacilli as Lactobacillus brevis. The presence of plasmids was demonstrated in all the species studied
- …
