Conservation of Glycerolated Cultures of Ochromonas danica and O. malhamensis at −10 C

SYNOPSIS. Ochromonas danica in a complex natural growth medium dies at 6–10 C in 4 days; O. malhamensis in ∼2 days. O. danica grown in the medium supplemented with 4.0% glycerol survived at −10±2 C for 35 days, and with 8% glycerol 29 days. O. malhamensis lasted only to 5 days in these media supplemented with 4% glycerol. Ethylene glycol and dimethylsulfoxide were too toxic to be effective. Difficulties in freeze-preservation of certain other phagocytic cells, notably blood granulocytes having comparatively simple flexuous outer membranes, add interest to use of O. danica and O. malhamensis as test organisms for preservation methods, especially in the convenient, inexpensive -10 to -20 C range. Biphasic media with an overlay of distilled water serve for conservation at room temperature. Problems of mutational erosion of these photosynthetic phagotrophs are discussed.     

Evidence for the Placental Transfer of <Superscript>3</Superscript>H-Acetyl-Melatonin

DEVELOPMENTAL studies on the enzymes which form melatonin, the putative pineal hormone, indicate that it probably is not formed in rats before the tenth day of life^1–3. Melatonin could nevertheless arise in animals younger than 10 days of age by transfer from the mother and we now describe how we have investigated this possibility by determining whether ³H-acetyl-melatonin injected into a pregnant rat could be detected in its foetuses.     

The articulation of cricket palps: morphology and movement patterns in behaviour

ABSTRACT. The morphology of the palp joints in Gryllus bimaculatus DeGeer is described in the context of their use in various behavioural situations. Two patterns of movements are distinguished: the goal-directed movement of each individual palp, as seen during grooming and food intake actions, and the rhythmic probing movement of the two maxillary palps together during exploratory behaviour and walking. Their details were studied by single frame analysis of video and cine records. The functional characteristics of the maxillary palps with regard to the dimensions of space within which they move in these patterns ('operational space') and the potential sensory stimuli they receive ('reception space') are compared with those of the antennae and discussed from the viewpoint of division of labour.