CONTROL OF SYNTHESIS OF RNA AND PROTEIN IN DIAPAUSING AND INJURED CECROPIA PUPAE

The functional organization of motor neurons in an insect ganglion

The distribution of motor nerve cell bodies in the metathoracic ganglion of the cockroachPeriplaneta americanawas mapped and displayed in three dimensions. A dense ring of ribonucleic acid (RNA) appears in the perinuclear cytoplasm of a nerve cell body whose axon has been cut in a peripheral nerve trunk. Using thisRNAring as the primary marker, 5 cell maps of ganglia from different animals were constructed to indicate which motor nerve cell body sends its axon out a particular peripheral nerve trunk. We count about 3000 neurons in the ganglion, and of these about 230 are above 20 /an in diameter. About 100 of these larger cells are generally arranged in bilaterally symmetrical pairs. These cell pairs have been assigned numbers and can be identified from one animal to another. Nerve cell bodies associated with nerves 3 through 6 send their axons out the ipsilateral nerve trunks. Cells associated with nerve 2 send their axons out the contralateral nerve trunk. This study may provide a basis for understanding the structural and metabolic organization responsible for the particular behavioural capacities of certain populations of neurons.

Biological effects of a 765-kV, 60-Hz transmission line on honey bees (Apis mellifera L.): hemolymph as a possible stress indicator

Number of circulating hemocytes and hemolymph protein patterns of adult worker honey bees were analyzed as possible indicators of stress resulting from colony placement under a 765-kV transmission line. Although exposure to 55, 80, and 95 microA total induced hive current (THC) produced colony behavioral disturbance, there were no consistent effects on mean hemocyte counts at 55- or 95-microA THC. Age-dependent declines in circulating hemocyte number were similar in all exposure groups. There were no consistent differences in tube-gel electropherograms. No consistent differences were found in two-density slab-gel electropherograms based on ultrasensitive silver stain. The 67 positively charged and four negatively charged protein fractions from overwintering bees are two- to threefold more than currently reported in the literature.

Morphological and physiological studies of the silkmoth ovary I. The general histology and some histochemical properties of the ovary of Samia Cynthia (Drury)

Ovaries of the giant silkmoth Samia cynthia Drury have been studied histologically and histochemically during diapause, adult development, and after injury to the diapause animal. In addition to cellular changes involved in follicular growth and vitellogenesis, changes in the intermediate layer cells are very striking, showing a distinct pattern during ovarian development and after injury. Two types of granules, one periodic acid-Schiff (PAS) positive, the other paraldehyde-fuchsin (PF) positive, change in their number and distribution in the intermediate cells during development and after injury. The PAS-positive granules appear during the first one-third of development, increase in number and size until the tenth day, then gradually dwindle in number and size, and disappear in the adult cells. The PF-positive granules, present in moderate numbers in the diapause animal, decrease in number until the tenth day of adult development, then reappear, and are present again in adult intermediate cells. After injury to a diapause pupa, intermediate cells show a greatly increased number of PF-positive granules, but none that are PAS-positive. The PAS-positive granules are a neutral or mildly acidic mucosubstance, and may correspond to lysosomal activity, while the PF-positive granules may be a neurosecretory-like substance or the product of hormone-dependent protein synthesis, since the patterns of granule distribution in the intermediate cells seem to reflect both general metabolic and hormone-related events.

Further experiments on the effect of actinomycin D on phytochrome-mediated anthocyanin synthesis

Phytochrome-mediated anthocyanin synthesis of the mustard seedling can be blocked by moderate concentrations of Actinomycin D (10 μg/ml in the solution around the seedling) if the substance is applied before the onset of far-red light (Fig. 1). If, however, the seedlings are irradiated with far-red for 6 hours, transferred to the dark for one hour, incubated with Act. D for 3 hours (in the dark) and then re-irradiated with continuous far-red, anthocyanin synthesis can only partially be inhibited (Fig. 2). - There are good arguments that the physiological action of the small stationary concentration of P730 which is left in the plant after we turn off the far-red light will virtually stop at the moment when the light is turned off (WAGNER and MOHR, 1966a). Furthermore the P730-dependent mRNAs which are involved in anthocyanin synthesis seem to be shortlived (LANGE and MOHR, 1965; MOHR and SENF, 1966; DURST and MOHR, 1966). Considering these arguments and the results of the present paper we cannot but conclude that genes which have once been activated by P730 will not return to the original state-at least with respect to Act. D sensitivity-even when the activating (or de-repressing) agent (P730 in our case) has disappeared.

Effects of actinomycin D on nucleic acid metabolism and protein biosynthesis during metamorphosis of Tenebrio molitor L

1. Injection of 0.16mug. of actinomycin D into pupae of the beetle Tenebrio molitor L. results in the development of modified adults in which the head and thorax are essentially adult while the abdomen and wings remain pupal-like. It is suggested that the messenger RNA for the development of head and thorax is present in the animal from the first day of pupation. 2. Injection of 0.16mug. of actinomycin D brings about 51-67% inhibition of labelled uridine incorporation into RNA. 3. When thymus DNA is mixed with actinomycin D before injection into pupae the latter develop into normal adults. This protection does not occur when DNA and actinomycin D are injected separately. 4. The inhibition of incorporation of labelled uridine into RNA by actinomycin is diminished to some extent when DNA and actinomycin D are injected separately and abolished if they are injected together. 5. Inhibition of RNA synthesis by actinomycin D in vitro is fully reversible. DNA or deoxyguanosine can reverse the effect of actinomycin D. 6. Incorporation of labelled glycine into protein is not affected by actinomycin D injection during the first 6 days of pupation. On the seventh day it becomes diminished in control pupae but this effect is prevented by actinomycin D. It is suggested that the template for protein synthesis is stable during the first 6 days of metamorphosis and that on the seventh day there is a qualitative change in the protein synthesized on the template.