Search results for "Agar plate"
showing 10 items of 30 documents
Serotyping and genotyping of encapsulated Escherichia coli K1 sepsis isolates with a monoclonal IgG anti K1 antibody and K1 gene probes
1987
Among infectious diseases caused by E. coli the capsular type K1 plays a predominant role. E. coli K1 isolates account for 80% of cases of E. coli neonatal meningitis and 30% of E. coli sepsis strains. Serotyping of K1 strains has conventionally relied upon the use of K1-specific bacteriophages or serum agar methods with polyvalent anti K1 serum. In the study present here, 187 E. coli sepsis isolates have been analysed for production of the K1 antigen using K1 phages, K1 serum agar plates and Latex agglutination and ELISA using an IgG2a anti K1 monoclonal antibody. In total, 33 sepsis isolates (about 18%) were identified as K1 positive, with three of these strains proving negative in all te…
Presence and characterisation of verotoxin producing E. coli in fresh Italian pork sausages, and preparation and use of an antibiotic-resistant strai…
2005
One hundred and twenty six samples of fresh pork sausages were analysed-for the presence of verocytotoxigenic Escherichia coli (VTEC). Selective enrichment followed by DNA extraction and PCR amplification of the stx1 and stx2 genes highlighted the occurrence of the above mentioned genes in 20 out of 126 samples screened. From the stx positive enriched cultures, isolation was performed on CT-SMAC agar plates after immuno-magnetic separation of E. coli O157. Fifty three non-sorbitol fermenting isolates were obtained and further characterised, along with the reference strain E. coli ATCC 35150(T). All the isolates were characterised by PCR assays, assessing the presence of stx1, stx2, rfbE(O15…
Modeling the effect of ethanol vapor on the germination time of Penicillium chrysogenum.
2005
The influence of ethanol vapor on germination of Penicillium chrysogenum was determined on yeast nitrogen base plus glucose agar medium at 25 degrees C. Ethanol vapors were generated by 0 to 6% (wt/wt) ethanol solutions at the bottom of hermetically closed petri dishes. The logistic equation was used to describe the data as the percentage of germination versus time and to estimate the germination time. The effect of ethanol concentration on germination time was described by a new reparameterized equation, resulting in an estimated limiting ethanol concentration of 4.3%. Up to 3% ethanol, all spores germinated, and the germination time increased with increasing ethanol concentration. At 3.5 …
PVC silver zeolite composites with antimicrobial properties
2011
Poly(vinyl chloride) (PVC) composites containing increasing amounts (2-20%, w/w) of silver zeolite (SZ) were prepared by melt mixing and characterized by thermal, mechanical and rheological analyses. The addition of large amount of SZ did not influence the processability and the formability of the composites, if compared to neat plasticized PVC. The antibacterial activity of PVC SZ composites was tested on Escherichia coli and Staphylococcus epidermidis and resulted promising both in culture broth and on agar plate and also in sterile urine seeded with these strains, for simulation purposes. In sterile urine, composites induced a significant reduction (4-6 log units) of viability of both st…
Bacteria of the Genus Roseobacter Associated with the Toxic Dinoflagellate Prorocentrum lima
1998
The dinoflagellate Prorocentrum lima is known to produce diarrhetic shellfish poisons. However, it is yet unclear if the dinoflagellates themselves or the bacteria associated with them produce the toxins. Here we analyze the toxicity as well as the spectrum of bacteria in two cultures of P. lima, namely P. lima-SY and P. lima-ST, which initially derived from the same P. lima strain PL2V. Toxicity tests, applying the Artemia bioassay revealed in both cultures high levels of toxins. The bacteria, associated with the two cultures, were identified by PCR/nucleotide sequence analysis of the 16S rRNA gene. From cultures of P. lima-SY the dominant sequence was found to share a 93.7% similarity wit…
Micropropagation of Metrosideros excelsa
2008
Multiple shoots were induced on stem segments of a 8-year-old plant of Metrosideros excelsa Sol ex Gaertn. ‘Parnel’. Axillary shoots produced on uncontaminated explants were excised, segmented and recultured in the same medium to increase the stock of shoot cultures. The Murashige and Skoog (MS) medium, augmented with different concentrations of 2- isopenthenyladenine (2iP) and indole-3-acetic acid (IAA), either singly or in combinations, as potential medium for shoot multiplication by nodal segments was tested. In the following experiment equal molar concentrations of four cytokinins [2iP, kinetin, zeatin and N6-benzyladenine (BA)] in combination with equal molar concentrations of three au…
Micromanipulation Techniques for the Isolation of Single Microorganisms
2005
A prerequisite for the biochemical and physiological investigation of microorganisms is the isolation and management of pure cultures. The only absolute criterion of purity for a bacterial culture is that it has been derived from the progeny of a single cell. Failure to apply this criterion may lead to much effort in proving the purity of a culture. All strains upon which research is to be based should therefore be rigorously purified before starting to investigate the properties of individual organisms (Johnstone 1969). Ecologically oriented microbiologists are faced especially with the problem of how to obtain a pure culture of certain microbial strains from their densely populated natura…
Wall mannoproteins in cells from colonial phenotypic variants of Candida albicans.
1990
Candida albicans ATCC 26555 switched at high frequency (10(-1) to 10(-3)) between several phenotypes identified by colony morphology on a defined mineral amino-acid-containing agar medium supplemented with arginine and zinc (LAZ medium). When cells taken from colonies exhibiting distinct morphologies were plated directly onto LAZ agar, spontaneous conversion to all the variant phenotypes occurred at combined frequencies of 2.1 x 10(-1) to 9.5 x 10(-3). However, when cells taken from the different colonial phenotypes were plated directly onto an undefined medium (yeast extract/peptone/dextrose; YPD medium), or first incubated in liquid YPD medium and then cloned on YPD agar, all colonies obs…
Is the re-use of sterilized implant abutments safe enough? (Implant abutment safety)
2019
Background: The reuse of implant healing abutments is common in dental practice. Effective elimination of bacteria and viruses is accomplished by conventional sterilization. The aim of this work was to explore the eventual survival of microorganisms on sterilized healing abutments and to rule out the presence of transmissible organic material after standard procedures. Material and Methods: A total of 55 healing abutments previously used in patients will be washed and sterilized in a steam autoclave at 121oC for 15 min. Each healing abutment will be cultured in Brain Heart Infusion broth (BHI) under strict aseptic conditions. Besides, two control groups will be included: one of 3 unused hea…
Antibacterial Activity of Positively and Negatively Charged Hematite (α-Fe2O3) Nanoparticles to Escherichia coli, Staphylococcus aureus and Vibrio fi…
2021
This research and work has been supported by the European Regional Development Fund within the Activity 1.1.1.2 “Post-doctoral Research Aid” of the Specific Aid Objective 1.1.1 (i.e., “to increase the research and innovative capacity of scientific institutions of Latvia and the ability to attract external financing, investing in human resources and infrastructure”) of the Operational Programme “Growth and Employment” (No. 1.1.1.2/VIAA/2/18/331).