The main microclimate parameters, i.e. bacterial count and airborne emission to the immediate environment, were analyzed in a dairy barn. Air temperature, relative humidity and air flow velocity were measured on an attested Testo 400 device (Testo Inc., Germany). Air samples were collected by use of a Merck MAS-100 device (Merck KgaA, Darmstadt, Germany) onto a commercially available nutrient Columbia agar (Biolife, Milan, Italy) and incubated for 24 h in an incubator at 37oC work temperature. Measurements were carried out once a week in the morning, at noon, and in the evening during October and November 2002. In the barn, measurements were performed in the animal housing area along the feedlot, and outside the barn at a distance of 5 m, 25 m and 50 m eastward and westward from the barn. The measured dairy barn temperature ranged from 11.2oC to 13.1oC, relative humidity from 71.3-78.6%, and air flow velocity from 0.09-0.11 m/s. The mean value of total bacterial count in the barn air ranged from 2.82 x 104 cfu/m3 at noon to 7.76 x 104 cfu/m3 in the evening. Bacterial count decreased at particular measuring sites outside the barn, with Wilcoxon matched pair test showing statistical significance (p<0.05) at a distance of 5 m eastward and 5 m westward of the barn.
The purpose of this study was establishing the basic energetic parameters of amoeba Acanthamoeba castellaniimitochondria respiring with malate and their response to oxidative stress caused by hydrogen peroxide in the presence of Fe2+ions. It appeared that, contrary to a previous report (Trocha LK, Stobienia O (2007) Acta Biochim Polon 54: 797), H2O2-treated mitochondria of A. Castellanii did not display any substantial impairment. No marked changes in cytochrome pathway activity were found, as in the presence of an inhibitor of alternative oxidase no effects were observed on the rates of uncoupled and phosphorylating respiration and on coupling parameters. Only in the absence of the alternative oxidase inhibitor, non-phosphorylating respiration progressively decreased with increasing concentration of H2O2, while the coupling parameters (respiratory control ratio and ADP/O ratio) slightly improved, which may indicate some inactivation of the alternative oxidase. Moreover, our results show no change in membrane potential, Ca2+uptake and accumulation ability, mitochondrial outer membrane integrity and cytochrome crelease for 0.5–25 mM H2O2-treated versuscontrol (H2O2-untreated) mitochondria. These results indicate that short (5 min) incubation of A. Castellanii mitochondria with H2O2 in the presence of Fe2+ does not damage their basic energetics.
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