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B Wachter

Publications and source records attributed to B Wachter.

5 recordsLinked to original sources
PubMed1997

The anaerobic endproduct lactate has a behavioural and metabolic signalling function in the shore crab

This study presents the first evidence that, in invertebrates, the anaerobic endproduct lactate has an alarm signal function and induces metabolic and behavioural responses as in the anuran Bufo marinus. In support of this function, behavioural hypothermia was demonstrated in the shore crab Carcinus maenas. The animals moved to a cooler environment when exposed to hypoxic conditions. A decrease in preferred temperature of the same magnitude was also found when normoxic animals were injected with an iso-osmotic lactate solution resulting in a haemolymph concentration of approximately 12 mmol l-1. Under normoxic (PO2=>18 kPa) and moderately hypoxic conditions (PO2=12 kPa), injection of this lactate solution also caused a significant increase in the rate of oxygen consumption (100 and 50 % respectively). The increase in the rate of oxygen consumption was smaller and delayed, but lasted longer, under hypoxic conditions compared with normoxic conditions. Low but significant correlations between levels of lactate and levels of adrenaline, octopamine and tryptophan suggest the involvement of biogenic amines in the mediation of the signal.

Journal Article↗
PubMed1996

Haemolymph flow distribution, cardiac performance and ventilation during moderate walking activity in Cancer magister (Dana) (Decapoda, Crustacea)

Adult male Cancer magister (Dana) were equipped with pulsed-Doppler flowmeters and pressure transducers for simultaneous measurement of heart and ventilation frequencies, haemolymph flow through each of the major arterial systems and cardiac output and for calculation of stroke volume. Each variable was measured at rest and during two consecutive periods of moderate treadmill walking activity and recovery. During activity, haemolymph flow through the sternal and anterolateral arteries increased, while flow through the hepatic arterial system decreased. This resulted in a redistribution of haemolymph flow in which a proportion of cardiac output was shifted from the anterior, posterior and hepatic arterial systems to the sternal arterial system. The relative proportion of the cardiac output flowing through the anterolateral artery remained constant. This indicated that oxygen supply was shifted away from the digestive system to the muscles of the walking legs and the respiratory system. Cardiac output, heart rate and stroke volume all increased in response to activity. The increase in cardiac output is the result of a large increase in stroke volume and a small increase in heart rate. A doubling of ventilation rate also occurred during activity. Both the circulatory and ventilatory systems were restored to pre-activity values by 60 min of recovery.

Journal Article↗
PubMed1988

2H(d

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Journal Article↗
PubMed1981

Rubescenslysin and phallolysin release marker molecules from phospholipid cholesterol liposomes.

Multilamellar liposomes were prepared from phospholipid, cholesterol and dicetyl phosphate and marked with potassium chromate or with glucose. They were treated with 0.5--50 haemolytic units (HU)/ml of rubescenslysin from Amanita rubescens or of phallolysin from Amanita phalloides. Rubescenslysin caused a dose-dependent release of marker molecules from phosphatidylcholine and from sphingomyelin liposomes. A statistically significant marker leakage was caused by 0.5--1 HU/ml from liposomes prepared from sphingomyelin, phosphatidylcholine from egg yolk, and among the synthetic phosphatidylcholines from distearoyl greater than dipalmitoyl greater than dioleoyl phosphatidylcholine. With the lysin concentrations tested, at the best 50% of total markers were released from sphingomyelin liposomes and 75--95% from phosphatidylcholine liposomes. Also phallolysin released marker molecules from phosphatidylcholine liposomes; statistically significant amounts were released by 0.5 HU/ml from egg yolk phosphatidylcholine and from dipalmitoyl congruent to distearoyl greater than dioleoyl phosphatidylcholine liposomes; 60--90% of maximum release was achieved at the best. However, liposomes prepared from (bovine) sphingomyelin were resistant to phallolysin; even with 50 HU/ml no leakage of markers was observed. Heat-inactivated rubescenslysin, heat-inactivated phallolysin and human serum albumin failed to release markers. Our results lead to the conclusion that both, rubescenslysin and phallolysin, interact with membrane phospholipids, phallolysin showing a higher degree of specificity.

Amanitins↗