Preliminary evidence for the hormonal control of urea concentration in the marine pulmonate,Onchidium verruculatum

Changes in blood, hepatopancreas and kidney urea concentrations in O. verruculatum have been assessed in response to endocrinological provocations. Two hr after pleurovisceral (PV) ganglion removal blood and nephridial urea levels were found to be significantly lowered and elevated respectively, whereas the hepatopancreas urea value remained unaltered, over the sham control. Unboiled and boiled macerates of PV (2 gn/animal) ganglion were effective in significantly inhibiting urea levels in blood and kidney of normal intact individuals. The possibility of a neurohormone from the PV, influencing tissue urea levels is discussed.     

Changes in the neurosecretory cells of the freshwater snail,lymnaea acuminata induced by urea administration

Data on biomass, production and metabolism of the biota, gathered during many years in the Rybinsk Reservoir, USSR, were used to calculate functional interconnections between separate components of the ecosystem, neglecting fluctuations of biomass and postulating a stationary state of the system.A matrix of interconnections was constructed and the influence of an increase or decrease of the biomass of one element upon all other elements of the ecosystem was calculated and discussed.     

Inhibition, of hormone-induced ethylene synthesis by the indole plant-growth inhibitor from Abrus precatorius seeds

The plant growth inhibitory fraction from Abrus precatoriusseeds inhibited protein and RNA synthesis and IAA- and kinetin-stimulatedethylene production by lettuce seedlings as well as IAA-stimulatedgrowth and ethylene production by wheat coleoptile sections. (Received August 28, 1974; )