Search results for "Culture media"

Survival of fish-virulent strains ofPhotobacterium damselaesubsp.damselaein seawater under starvation conditions

1998

The survival of fish-virulent strains of Photobacterium damselae subsp. damselae in seawater microcosms, with and without sediment, was investigated. The strains survived as culturable bacteria at 14 and 22 degrees C for at least 1 year, and infectivity for fish was maintained. At 5 degrees C, cells lost culturability on solid media, but this was recovered when the temperature was increased to 22 degrees C. Finally, morphological changes in the bacterium (rod to coccus), and production of vesicles and extracellular material were observed during the time of starvation. The overall results suggest that seawater and sediment can act as reservoirs for these virulent strains.

Hemin-coupled iron(III)-hydroxide nanoparticles show increased uptake in Caco-2 cells

2011

Abstract Objectives The absorption of commonly used ferrous iron salts from intestinal segments at neutral to slightly alkaline pH is low, mainly because soluble ferrous iron is easily oxidized to poorly soluble ferric iron and ferrous iron but not ferric iron is carried by the divalent metal transporter DMT-1. Moreover, ferrous iron frequently causes gastrointestinal side effects. In iron(III)-hydroxide nanoparticles hundreds of ferric iron atoms are safely packed in nanoscaled cores surrounded by a solubilising carbohydrate shell, yet bioavailability from such particles is insufficient when compared with ferrous salts. To increase their intestinal uptake iron(III)-hydroxide nanoparticles …

Accumulation of Tetradifon in an Algae ( Nannochloris oculata ) and the Cladoceran, Daphnia magna

1996

Assessment of the toxicity of a pesticide with a two-generation reproduction test using Daphnia magna.

2000

Abstract Daphnia magna (F 0 generation) were exposed during 21 days to different diazinon concentrations. Offspring (animals from the first and third brood: F 1 (1st) and F 1 (3rd), respectively) were transferred to a free pesticide medium during a 21-day recovery period. The algae Nannochloris oculata (5×10 5 cells/ml) were used as food. In this recovery study, survival, growth and reproduction (mean total young per female, mean brood size, onset of reproduction and mean number broods per female) were assessed as individual parameters, and the intrinsic rate of natural increase ( r ) as population parameter for F 1 (1st and 3rd broods) daphnids. Reproduction as well as survival was still r…

Bioproduction of an extract from Penicillium funiculosum Thom with activity against Ceratitis capitata and Tetranychus urticae

1993

The bioproduction conditions of a crude extract from a strain of Penicillium funiculosum Thom, which shows activity against Ceratitis capitata and Tetranychus urticae, have been optimized. The efficacy degree was 95% (C. capitata) and 100% (T. urticae), according to Abbot. This is the first report on the pesticide activity of an extract from P. funiculosum against these species. The best yields were obtained when P. funiculosum was grown in Raulin-Thom medium at pH 6.5 with sucrose candy as the carbon source and ammonium sulphate and phosphate as the nitrogen source. Other favourable conditions were static cultures, at 28 degrees C, and in the dark.

Establishment of different T cell sublines using either interleukin 2 or interleukin 4 as growth factors

1990

Purified protein derivative reactive T cell lines were established under identical conditions with the exception that different lymphokines, namely interleukin (IL) 2 and IL 4 were employed as growth factors. IL 2 favored the development of T cell lines (LNC.2) which upon activation by concanavalin A (Con A) secreted predominantly lymphokines characteristic of TH1 cells. By contrast, T cell lines established with the aid of IL 4 as growth factor (LNC.4) produced mainly lymphokines representative of TH2 cells. Apart from their pattern of lymphokine secretion LNC.2 and LNC.4 T cells were found to differ in their proliferative response to lymphokines and Con A. LNC.2 T cells proliferated only …

A proton-translocating H+-ATPase is involved in C6 glial pH regulation.

1998

AbstractGlial cells extrude acid equivalents to maintain pHi. Although four mechanisms have been described so far, pHi-control under physiological conditions is still not sufficiently explained. We therefore investigated whether a H+-translocating ATPase is involved in glial pHi homeostasis using an established glial cell line (C6 glioma). In the absence of bicarbonate, the inhibition of H+-ATPases by NEM led to a pHi decrease. The application of a more specific inhibitor (NBD-Cl) showed that the H+-ATPase involved is of the vacuolar type. Inhibition went along with delayed cell swelling. Together with the fact that glial acidification was far more pronounced in Na+-free media, this may ser…

Different and common intracellular calcium-stores mobilized by noradrenaline and caffeine in vascular smooth muscle.

1992

Noradrenaline (NA) 1 microM and caffeine (CAF) 10 mM induce a contractile response in isolated rat aorta maintained at 37 degrees C either in the presence or absence of extracellular calcium. In Ca-free media the contractile response was reduced and contractile activity of CAF only occurred at 25 degrees C. NA induced a biphasic response in Ca-free medium, with a fast phasic contraction followed by a smaller more sustained contraction. The response induced by CAF consisted of a fast transient contraction which returned to a level below the resting tone. After washing, further addition of NA or CAF evoked no increase in smooth muscle tension. The influence of Mg-depletion in the extracellula…

Energy metabolism and intracellular pH in boar spermatozoa

2003

The effect of energy metabolism on intracellular pH was studied in boar spermatozoa using nuclear magnetic resonance (NMR) spectroscopy and confocal microscopy with the pH-sensitive dye seminaphthorhodafluor (SNARF-1). Freshly ejaculated spermatozoa had a high adenylate energy charge (AEC=0.8), which decreased to 0.6 under aerobic conditions and to 0.2 under anaerobic conditions. Correspondingly, no ATP resonances but high AMP resonance were visible in (31)P-NMR-spectra of the spermatozoa. When an artificial oxygen buffer (Fluosol) and a purpose-built air supply system were used during (31)P-NMR data acquisition, ATP resonances reappeared whereas the AMP resonance disappeared. Boar spermato…

Reduced Apo-Fumarate Nitrate Reductase Regulator (ApoFNR) as the Major Form of FNR in Aerobically Growing Escherichia coli▿

2008

ABSTRACT Under anoxic conditions, the Escherichia coli oxygen sensor FNR (fumarate nitrate reductase regulator) is in the active state and contains a [4Fe-4S] cluster. Oxygen converts [4Fe-4S]FNR to inactive [2Fe-2S]FNR. After prolonged exposure to air in vitro, apoFNR lacking a Fe-S cluster is formed. ApoFNR can be differentiated from Fe-S-containing forms by the accessibility of the five Cys thiol residues, four of which serve as ligands for the Fe-S cluster. The presence of apoFNR in aerobically and anaerobically grown E. coli was analyzed in situ using thiol reagents. In anaerobically and aerobically grown cells, the membrane-permeable monobromobimane labeled one to two and four Cys res…