HEPES buffer in ovary-transportation medium influences developmental competence of cattle oocytes

This study was conducted to investigate the effects of ovary transportation in a semi-complex medium containing HEPES at different temperatures on the developmental competence and the quality of in vitro-produced embryos. The cattle ovaries were transported in normal saline (NS), phosphate buffer saline (PBS), K simplex optimization medium (KSOM), Chatot-Ziomek-Bavister medium (CZB) and Charles Rosenkrans medium (CR1) at various temperatures (38 ºC, 25 ºC and 4 ºC). The developmental competence of retrieved cumulus oocyte complexes (COCs) was evaluated by maturation, fertilization, morula and blastocyst formation and numbers of inner cell mass (ICM) and trophectoderm (TE) cells. The COC maturation rate was affected by medium and temperature. It was found that 4 ºC resulted in a higher maturation (81.0 ± 4.75) rate than other transportation temperatures. The CR1 (80.5 ± 6.66) and KSOM (80.2 ± 6.15) gave a better maturation rate than the others. Fertilization rate, which was evaluated by cleavage rate, was not affected by transportation temperature. However, the transporting medium had a significant effect on the fertilization rate. Moreover, CR1 (43.6 ± 4.60), KSOM (43.2 ± 4.86) and CZB (41.1 ± 4.86) media gave higher percentages of cleaved embryos. There was no significant difference in morula and blastocyst formation rate or in ICM and TE cell counts regarding transportation factors. In conclusion, the transport of ovaries in CR1 at 4 ºC is effective for maintaining early developmental competence of cattle oocytes.Keywords: Cattle embryo, in vitro embryo production, ovary transportatio

Growth kinetics of streptococcus thermophilus at subbacteriostatic penicillin G concentrations

Streptococcus thermophilus may be subjected to the effects of penicillin G in contaminated milk used for yogurt production. Sensitivity of this microorganism to penicillin G has been conventionally determined by the help of penicillin G-impregnated disks placed on solid media. It was observed that the bacteriostatic penicillin G concentration was much greater in liquid media than in solid media. The conventional disk method may not be appropriate for antibiotic sensitivity determinations if the microorganisms will be used in liquid culture. A simple mathematical model simulated the growth of S. thermophilus in liquid culture. Numerical values of this model's parameters were regarded as the measure of the antibiotic effect on the culture. In penicillin G containing fresh medium, small concentrations of antibiotic decreased the specific growth rate considerably. Increasing the antibiotic concentration caused only slight additional decline. Antibiotic shock, i.e., rapidly introducing penicillin G into an actively growing antibiotic-free culture, stopped growth of the penicillin G-resistant microorganisms, and no death was observed, but a fraction of the microorganisms were killed in the wild culture. Both the wild and the resistant cultures recovered from the shock in a few hours. Addition of penicillin G-resistant microorganisms together with the antibiotic dosage into the wild culture prevented death

An explorative study regarding the individual response to terrorism risk perception on food chain security - a social-cognitive perspective in case of Romania and Turkey

In 2002, World Health Organization published "Terrorist Threats to Food", which was intended primarily for policy-makers in national governments with responsibilities for ensuring food safety, and was designed to assist them in incorporating considerations of food terrorism into existing food safety systems. In this context, food terrorism was defined as 'an act or threat of deliberate contamination of food for human consumption with biological, chemical and physical agents or radio-nuclear (CBRNE) materials for the purpose of causing injury or death to civilian populations and/or disrupting social, economic or political stability'

Purification and characterization of a bacteriocin from an oenological strain of Leuconostoc mesenteroides

Malolactic fermentation (MLF), which improves organoleptic properties and biologic stability of some wines, may cause wine spoilage if uncontrolled. Bacteriocins were reported as efficient preservatives to control MLF through their bactericidal effect on malolactic bacteria. Leuconostoc mesenteroides subsp. cremoris W3 isolated from wine produces an inhibitory substance that is bactericidal against malolactic bacteria in model wine medium. Treatment of the culture supernatant of strain W3 with proteases eliminated the inhibitory activity, which proved that it is a true bacteriocin and we tentatively termed it mesentericin W3. The bacteriocin inhibited the growth of food-borne pathogenic bacteria such as Enterococcus faecalis, Listeria monocytogenes, and malolactic bacteria. It was active over a wide pH range and stable to organic solvents and heat. Mesentericin W3 was purified to homogeneity by a pH-mediated cell adsorption-desorption method, cation exchange, hydrophobic interaction, and reverse-phase chromatography. Matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectroscopy (MS) and partial amino acid sequence analysis revealed that mesentericin W3 was identical to mesentericin Y105