Morris Rockstein’s research while affiliated with University of Miami and other places

The enzyme alpha-glycerophosphate dehydrogenase was examined for homogeneity by gel electrophoresis in the extramitochondrial fraction of the thorax of the adult male housefly, Musca domestica. The absence of isozyme forms of this enzyme at any one age, and for each of three different post-emergence age levels (1 day, 5 days, and 12 days of adult life) was confirmed by the identical absolute mobilities obtained for the respective enzyme proteins extracted, thereby indicating a single homogenous enzyme regardless of age, for this species. Moreover, the absolute mobility of this enzyme was found to be identical with that for a purified, commercial preparation of rabbit muscle alpha-glycerophosphate dehydrogenase.

The neurosecretory material (NS) secreted by the medial neurosecretory cells (MNC) of the brain of the house fly, increases rapidly from a minimum to a peak level, from emergence to approximately 48 hours of adult age. This peak level persists through advanced old age. Ingestion of milk by the female releases the NS into the axons, which hormone release occurs just prior to the initiation of vitellogenesis. The availability of oviposition sites stimulates the female to lay eggs up to 45 days of age; in contrast to the male house fly, this is accompanied in the female by the persistence of NS in the axons of the MNC at that late date as well. This and other evidence indicates that the NS is either directly or indirectly involved (probably via the corpus allatum) with the regulation of protein and carbohydrate metabolism and, concomitantly, with the rate of aging of female house flies, in relation to their oviposition capacity and life span.

Reared on a diet of powdered whole milk, sugar, and water, male house flies show a marked increase in thiamine phosphate levels from the time of emergence to a maximum of 13 μg/g. by the fourth day. This is followed by a more gradual, but progressive, decline to a minimal level of 3 μg/g on the 22nd day of adult life. Thiamine phosphate levels of adult female thoraces likewise increase following emergence but do not reach their peak level (about 12·5 μg/g) until the 7th to 8th day, following which there is a much slower decrease to a level of 9·3 μg/g on the 25th day of female adult life. The possible relationship between carbohydrate metabolism in thoracic flight muscle and thiamine phosphate levels in relation to age is discussed.

The male housefly, Musca domestica, utilizes trehalose during flight. However, the rate of utilization of treahlose is most rapid during the first few minutes of continuous flight (i.e. during the first 5 min of flight, the rate of utilization of trehalose is 187 μg/thorax per hr; this results in a thoracic trehalose level of one-third of that of the unflown fly, after 5 min of flight). However, as the period of flight is extended, the apparent rate decreases very rapidly, so that the thoracic trehalose level actually continues to rise with increasing duration of flight period. It is concluded that, following initial rapid utilization of trehalose, a secondary metabolic pool becomes implicated, so as to restore (and maintain) the thoracic trehalose levels at as high as 50 per cent of that of unflown flies, for thoraces of flies which have been permitted to fly for as long as 4·5 hr. Flight-exhausted flies, when fed on a solution of glucose, fructose, maltose, sucrose, and trehalose, resumed flight, without external stimulation, but feeding galactose, mannose, and cellobiose failed to do so. However, injection of solutions of glucose, fructose, sucrose, and trehalose did not initiate flight in such flight-exhausted flies. These data indicate that a complex, metabolic route is normally involved in the energizing of flight.

Zusammenfassung Trehalose der Flügelmuskeln männlicher Hausfliegen,Musca domestica (1 h bis 16 Tage alt), wurde mit Filtrierpapierchromatographie getrennt und quantitativ kolorimetrisch bestimmt. Die Konzentration der Trehalose in den Flügelmuskeln erreicht ihr Maximum (26,50 µg/Thorax) 4 h nach dem Schlüpfen der Imago. Nach 24 h (Imago) auf ⅓ des Maximums (8,59 µg/Thorax) vermindert, stabilisiert sich der Trehalosegehalt bis zum Lebensende.

Exposure of 36- to 48-hour-old pupae of the common house fly, Musca domestica, L., to single doses of x rays ranging from 2000 to 8000 rads had no appreciable effect on the percentage of emergence or on the normal appearance of the adult flies. All levels of radiation produced only a slight but significant decline in female life span. Such low levels of x-irradiation produced only a slight effect on male life span, with a decrease for 2000 rads, no effect at 4000 rads, and a slight increase at 6000 and 8000 rads. However, the effect of such x-irradiation on the otherwise normally high degree of wing loss in male house flies was much more striking, the number of male house flies retaining their wings at the time of death being trebled for all four dose levels studied. In the females, there was a smaller but nevertheless significant increase in such wing retention.

In a long-range study of aging in the house fly, Rockstein and his co-workers (Rockstein, 1956, 1957 ; Rockstein alId Brandt, 1963 ; Rockstein and Gutfreund, 1961 ) have previously noted that abrading and ultimate loss of wings, especially in the niale house fly, is preceded and then acconipanied l)V tile failure or decline of specific intracehiuhar biocheniical coniponeiits (enzynies, coenzymes, etc. ) of the. thoracic flight muscle, whichl are directly or indirectly concerned with the energizing of the contraction of flight muscle. Corresponding niicroanatoniical chianges were siniilarhy reported by Rockstein and Bhatnagar (1965) in describing tue age-related distribution of number and size of giant mitochiondria of maturing and senescent male and female house flies. The study on iviiicii this report is h)ased was undertaken in order to estabiisll niore precisely the age-related, quantitative changes in flight ability, i.e. , the wing i)eat frequency and duration of flight, for male and female house flies from emer gence to senility. MATERIALS AND METHODS A iong-mbred (NAIDM) strain of IlIusca domestica L., niaiiltained in our laboratory at 80° F. and 45% R.H., was used in this study. Tue experimental population was ol)tamed by allowing 4- to 5-day-old females to hay' eggs on a standardized artificial medium described earlier (Rockstein, 1957). From the time of emergence and during tue course of the entire experiment, all flies were allowed to feed ad ithitum OD sucrose, twice daily, for a period of one hour each feeding; such flies were considered to be fulhy satiated as far as their carbohydrate require ments were concerned. A continuous supply of water was provided throughout the period of study. For tile study of wing beat frequency (WBF), flies of known age, immediately after having beeii previously fed Oil sucrose for au hour, were aiiesthietized wider carbon dioxide, sexed, and mounted (attached individually in the dorsal midthioracic region with Duco®cemeiit) onto thin, inverted “¿�J”-shaped copper wire supports, which have been set in fine holes drilled in a wooden block 6”x 1.5”. Removal of tarsi or of any substratuni, essential for the initiation and sustenance of flight in the case of Phorinia. (Friedman, 1959; Ciegg and Evans, 1961) or of Drosophila (Williams et a!., 1943), was fouiid to be quite unnecessary for initiating or niain taming flight in the house fly, which normally flies spontaneously when so sup 1 Supported in part by funds froni the United States Public Health Service, Research Graiit No. HD 00571 from the National Institute of Child Health and Human Development.

Pupae of the house fly, Musca domestica L., when exposed to single doses of X-rays, varying between 10,000 to 30,000 rad, show a correlation between dosage and emergence. At 10,000 and 15,000 rad 90.1 % to 73.9% of the flies, respectively, emerge. This figure declines to 42.5% at 20,000 and 19.5% at 30,000 rad. The number of flies dying in the pupal stage correspondingly increases with an increase in radiation dose. The implications of these results are discussed.