Drinking rates and Na+ effluxes in response to temperature change in two species of marine flatfish: dab,Limanda limanda and plaice,Pleuronectes platessa

The relationship between fish mass and drinking rate in two species of flatfish, dab and plaice, weighing between 1 and 150 g was investigated. Both plaice and dab showed increased drinking rates with increasing fish mass, although — when calculated on a weight-specific basis — the increase was negligible. Fish were acclimated to winter and summer temperatures of 9 and 14°C, respectively. In winter both species were acutely transferred to 5, 14 and 21°C and in summer to 5, 9, 21 and 25°C. Drinking rates, Na⁺ efflux and body ion content were measured. Dab showed lower drinking rates than plaice (e.g. the weight-specific drinking rates of summer-and winter-acclimated dab were 0.12±0.01 and 0.06±0.006 ml·h^-1·100 g^-1, respectively, compared to that of plaice which were 0.25±0.02 ml·h^-1·100 g^-1 in summer and 0.17±0.02 ml·h^-1·100g^-1 in winter). Summer dab exhibited decreased weight-specific drinking rates at 5, 9 and 25°C, while winter dab increased drinking at 21°C. Winter plaice also showed increased drinking at 21°C and a decrease at 5°C, but in contrast summer plaice did not increase drinking at either 21 or 25°C but showed a decrease at 5 and 9°C. Winter dab and plaice showed similar Na⁺ efflux rates but summer dab showed higher efflux at all temperatures except 5°C. The data indicates that (a) the osmoregulatory function of plaice is much weaker than that of dab at higher temperatures (>20°C) and (b) mass has a greater effect on drinking and Na⁺ efflux rates than temperature; although when calculated on a weight-specific basis neither drinking nor efflux showed any variation with fish mass suggesting that these functions occur at similar intensities across the entire weight range.Abbreviations ANOVA analysis of variance - ⁵¹Cr-EDTA ⁵¹chromium ethylenediaminetetra-acetic acid - SW sea water     

Bericht Über die Arbeitsgruppe Für Datenver-Arbeitung der Internationalen Vereinigung Für Vegetationskunde, 1969–1970

Ohne Zusammenfassung     

Propionibacterium freudenreichii thrives in microaerobic conditions by complete oxidation of lactate to CO2

In this study we show increased biomass formation for four species of food-grade propionic acid bacteria (Acidipropionibacterium acidipropionici, Acidipropionibacterium jensenii, Acidipropionibacterium thoenii and Propionibacterium freudenreichii) when exposed to oxygen, implicating functional respiratory systems. Using an optimal microaerobic condition, P. freudenreichii DSM 20271 consumed lactate to produce propionate and acetate initially. When lactate was depleted propionate was oxidized to acetate. We propose to name the switch from propionate production to consumption in microaerobic conditions the ‘propionate switch’. When propionate was depleted the ‘acetate switch’ occurred, resulting in complete consumption of acetate. Both growth rate on lactate (0.100 versus 0.078 h⁻¹) and biomass yield (20.5 versus 8.6 g* mol⁻¹ lactate) increased compared to anaerobic conditions. Proteome analysis revealed that the abundance of proteins involved in the aerobic and anaerobic electron transport chains and major metabolic pathways did not significantly differ between anaerobic and microaerobic conditions. This implicates that P. freudenreichii is prepared for utilizing O₂ when it comes available in anaerobic conditions. The ecological niche of propionic acid bacteria can conceivably be extended to environments with oxygen gradients from oxic to anoxic, so-called microoxic environments, as found in the rumen, gut and soils, where they can thrive by utilizing low concentrations of oxygen.     

Acid-base balance in rainbow trout (Salmo gairdneri) subjected to acid stresses.

1. The respiratory properties of rainbow-trout blood were investigated in acid-stressed fish. In the first group acid was introduced into the bloodstream and in the second the carbon dioxide content of the ambient water was increased. 2. Initially the introduction of acid to the blood caused a decrease in blood pH and bicarbonate, and increases in oxygen uptake and ventilation volume. After 2-3 h these values had returned to the control levels. 3. Trout subjected to high ambient CO2 (about 10 mmHg) showed a decrease in blood pH while PCO2 and bicarbonate increased. After 8 h the trout began to show signs of compensation to the acidosis. 4. In each experiment the blood PO2 was little changed but blood O2 content was decreased and tended not to resume the control value even after several hours. 5. The results are discussed in terms of the various acid-base mechanisms thought to be available to the fish. These include branchial ion exchanges and the possible buffering roles of the extracellular and intracellular fluids.     

Some effects of adrenaline on anion transport and nitrite-induced methaemoglobin formation in the rainbow trout (Salmo gairdneri Richardson)

The effects of adrenaline on branchial anion transport and nitrite-induced methaemoglobinaemia have been investigated in rainbow trout. Nitrite uptake and efflux results suggest that adrenaline effects a net anion efflux principally by stimulation of the unidirectional branchial anion efflux. In oxygenated whole blood nitrite-induced methaemogloblin was significantly reduced in the presence of adrenaline. The physiological and environmental consequences of nitrite-induced stress are discussed.     

Three genes that encode human {beta}-galactoside {alpha}2,3-sialyltransferases. Structural analysis and chromosomal mapping studies

The synthesis of     

Decline and potential recovery of the European grey partridge (<Emphasis Type="Italic">Perdix perdix</Emphasis>) population—a review

Grey partridge populations showed drastic decreasing numbers throughout Europe. Existing knowledge of the causes of decline and the effectiveness of conservation measures was reviewed. Population studies from the UK indicated three periods: a stable population before 1950, sharply decreasing numbers in 1950–1970 and a continued decline after 1970. Other European studies fitted into this picture, with a 10-year lag in each period. The onset of population decrease corresponded with a sharp decrease in chick survival mainly caused by reduced insect availability due to pesticide use. Several factors caused the continued decreasing numbers after 1970, such as decreased hatching success and an increased role of predation. Measures to restore partridge numbers should firstly focus on the main cause of population decline, that is, improve foraging conditions to increase chick survival rate. Next to creation of special partridge habitat, conventional agriculture offers good opportunities to improve foraging conditions. Only when an integrative approach is adopted may large-scale habitat improvements be realised to restore population level to the level before 1950.