The transport of ammonia by various tissues throughout the body is of fundamental importance for nitrogen excretion in invertebrates, yet sites and mechanisms of ammonia transport are not presently well understood. In this thesis a novel ammonium-selective microelectrode was developed using the crown ether ionophore TD19C6, which is approximately 3800-fold more selective for NH 4 + than Na + co...

Article history: Received on: 24/04/2015 Revised on: 14/05/2015 Accepted on: 04/06/2015 Available online: 20/06/2015 Ageing is a natural life process whose manifestations are familiar and unambiguous. Oxidative modification of cellular molecules by reactive oxygen species and impaired antioxidant mechanism play unique role in a variety of age-associated degenerations. As a defence, cells have d...

We investigated divalent cation and anaerobic end-product concentrations and the interactive effects of these substances and pH on haemocyanin oxygen-binding (Hc-O(2)) in the New Zealand abalone Haliotis iris. During 24 h of environmental hypoxia (emersion), D-lactate and tauropine accumulated in the foot and shell adductor muscles and in the haemolymph of the aorta, the pedal sinus and adducto...

Animals carefully regulate the amount of protein that they consume. The quantity of individual essential amino acids (EAAs) obtained from dietary protein depends on the protein source, but how the proportion of EAAs in the diet affects nutrient balancing has rarely been studied. Recent research using the Geometric Framework for Nutrition has revealed that forager honeybees who receive much of t...

Strong tolerance of freezing is an important strategy for insects living in extremely cold regions. They produce highly effective cryoprotectant systems consisting of ice-nucleating proteins and polyols, which enables tolerable freezing of the body fl uid. Therefore, the measurement of the concentrations of polyols and the activity of ice nucleators in the haemolymph is an essential tool for de...

It is well known that application of L-glutamic acid to insect excitatory neuromuscular synapses leads to the production of depolarizing postsynaptic potentials, and this, with other evidence, has led to the belief that L-glutamic acid may be the chemical transmitter at these synapses (Pitman, 1971). It is also known that the haemolymph that bathes insect muscles contains L-glutamate at concent...

Air-breathing Cardisoma carnifex, collected in Moorea, French Polynesia, were held in fresh water similar in chemical composition to that in their burrows. Under control conditions, which allowed branchial chamber flushing but not ventilation of the medium, crabs demonstrated net Na and Cl~ uptake, and ammonia, urea and base excretion (= acidic equivalent uptake). Throughout 192 h of water depr...

The degradation of synthetic cydiastatin 4 (ARPYSFGL-amide) and cydiastatin 4 analogues cydiastatin 4alpha (PPPPPARPYSFGL-amide) and cydiastatin 4beta (PPPPPARPYSF[Acpc]L-amide) by enzymes associated with the midgut and/or haemolymph of the tobacco hawkmoth moth, Manduca sexta was investigated using reversed-phase high performance liquid chromatography (RP-HPLC) combined with matrix assisted la...

Chill tolerance of insects is defined as the ability to tolerate low temperature under circumstances not involving freezing of intracellular or extracellular fluids. For many insects chill tolerance is crucial for their ability to persist in cold environments and mounting evidence indicates that chill tolerance is associated with the ability to maintain ion and water homeostasis, thereby ensuri...

Disseminated neoplasia (DN) has been detected in cockles from various beds in Galicia (NW Spain). A study was performed to characterise cockle neoplastic cell ultrastructure and to evaluate the effect of this disease at different severity stages on various haemolymph cell parameters. Examination of cockle neoplastic cells with transmission electron microscopy (TEM) showed round shapes and a lac...