United kingdom: The Annual Report for 1988/89 of the Medical Research Council

United kingdom: The Annual Report for 1988/89 of the Medical Research Council     

A new biological activity for the neuropeptide FMRFamide: experimental evidence for a secretagogue effect on amylase secretion in the scallopPecten maximus

FMR Famide immunoreactivity in the digestive tract of the bivalve molluscPecten maximus was investigated by immunocytochemistry. Positive FMRFamide-like immunoreactivity was detected in nerve fibres in close contact with exocrine α amylase secreting cells. Physiological studies on enzymatically dissociated cells of the stomach-digestive gland complex demonstrated the involvement of FMR Famide and analogues in the control of α amylase release from the cells. The FMRF Famide-induced secretion was shown to be time- and dose-dependent. In contrast to most naturally occurring vertebrate secretagogues which are hormones, FMRFamide appears to work in our in vitro system as a paracrine factor.     

DNA,a controlling factor in the conversion of plasminogen to plasmin

Résumé Les résultats de ces études démontrent la formation de «complexes» entre l'acide désoxyribonucléique et la plasminogène. L'acide désoxyribonucléique inhibe l'action catalytique de la plasminogène humaine sur la plasmine.     

Aphanomyces root rot of cauliflower in Varanasi,a new recording for India

Zusammenfassung Eine Pilzinfektion der Blumenkohlwurzeln (Brassica oleracea var.botrytis) wird beschrieben. Als Urheber der Krankheit wird der pathogene PilzAphanomyces raphani Kendrick vermutet. Das Auftreten der Krankheit und ihres Erregers stellt fÜr Indien und eventuell auch fÜr andere asiatische Länder eine Neuentdeckung dar.     

Mode of action of a soluble restricted factor, a suppressor of the allogeneic proliferative response in man

Appearance of "suppressor cells" is induced by in vitro hyperimmunization of lymphocytes against allogeneic cells, incompatible for one HLA-DR antigen. These "suppressor cells under certain conditions, release in the culture medium, "suppressor factors" of the in vitro allogeneic proliferative response in Man. They are not immunoglobulins and act in a non specific way towards the stimulators. Only one of them is restricted to some individuals. This is shown when either responders or stimulators are incubated for different periods, with the "suppressor factors" prior to the primary mixed lymphocyte reaction (MLRI). The beneficial effect of transfusions on kidney graft survival, could be, in part, explained by a suppressor mechanism, analogous to the one described in vitro.     

Photoperiodic regulation of mating behaviour in the linden bug,Pyrrhocoris apterus,is mediated by a brain inhibitory factor

Active inhibition of mating behaviour in a male insect is reported here for the first time. InPyrrhocoris apterus L. (Heteroptera), the most important inhibitory pathway runs from the pars intercerebralis (PI) of the brain and does not pass through the corpora allata. The inhibitory activity of the PI is promoted by short day conditions and suppressed by long days. As the effect of photoperiod is delayed, transfer procedures enabled us to record daily rhythms in mating behaviour during short days. While the extirpation of the PI results in a discrete phase shift of the long day rhythm, there is a much less significant phase shift after this operation during short days. Thus the PI has been shown to mediate the effect of photoperiod on both the inhibition and the rhythm of mating behaviour.     

Endogenous synthesis of peptidoglycan in eukaryotic cells; a novel concept involving its essential role in cell division,tumor formation and the biological clock

Degradation products of peptidoglycan, the universal bacterial cell wall constituent, were previously found in animal tissues and urine. Reassessment and quantitative analysis of available data lead to an original concept, i.e. that eukaryotic cells synthesize peptidoglycan. We present a model in which this endogenously synthesized peptidoglycan is essential for the processes of eukaryotic cell division and sleep induction in animals. Genes for peptidoglycan metabolism, like those for lysine biosynthesis in plants, are probably inherited from endosymbiotic bacteria, the ancestors of mitochondria and chloroplasts. Corollaries of this concept, i.e. roles for peptidoglycan metabolism in tumor formation and in the biological clock, are supported by abundant evidence. We propose that many interactions between bacteria and eukaryotes are conditioned by their common genetic heritage.     

The Penicillium chrysogenum antifungal protein PAF, a promising tool for the development of new antifungal therapies and fungal cell biology studies

In recent years the interest in antimicrobial proteins and peptides and their mode of action has been rapidly increasing due to their potential to prevent and combat microbial infections in all areas of life. A detailed knowledge about the function of such proteins is the most important requirement to consider them for future application. Our research in recent years has been focused on the low molecular weight, cysteine-rich and cationic antifungal protein PAF from Penicillium chrysogenum, which inhibits the growth of opportunistic zoo-pathogens including Aspergillus fumigatus, numerous plant-pathogenic fungi and the model organism Aspergillus nidulans. So far, the experimental results indicate that PAF elicits hyperpolarization of the plasma membrane and the activation of ion channels, followed by an increase in reactive oxygen species in the cell and the induction of an apoptosis-like phenotype. Detailed knowledge about the molecular mechanism of action of antifungal proteins such as PAF contributes to the development of new antimicrobial strategies that are urgently needed. Received 09 August 2007; received after revision 17 September 2007; accepted 19 September 2007