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Biomedical subjects

B Sutherland

Publications and source records attributed to B Sutherland.

At least 55 records · Page 3Linked to original sources
PubMed1987

The colonization and life-cycles of Musca lusoria, Musca xanthomelas and Musca nevilli, vectors of Parafilaria bovicola in South Africa.

Thriving, permanent colonies of Musca xanthomelas and later of Musca nevilli were successfully established. However, because of the low reproduction potential of Musca lusoria a small colony only was kept for a limited period until life-cycle studies were completed. Larvae were reared on fresh dung from cattle fed lucerne, while in general adults were fed 0.3% citrated ox-blood, whole milk powder, sugar crystals, fresh dung and water. M. nevilli could be colonized only when ox-liver was substituted for ox-blood. A comparison of the life-cycles of M. lusoria and M. xanthomelas under laboratory conditions at a constant temperature of approximately 27 degrees C, 60% R.H. and 24 h illumination revealed major differences between these 2 vector species. M. lusoria deposits single larvae at intervals of approximately 2 days and a female can produce up to 27 in her life-time. An M. xanthomelas female can lay up to 4 batches of eggs, with as many as 33 eggs per batch, at intervals of approximately 5 days. A single female can produce a maximum of 94 eggs. M. lusoria, however, showed survival advantages over M. xanthomelas in that its larvae reached the pupal stage at least a day sooner and its adults survived more than twice as long. The life-cycles of M. xanthomelas and M. nevilli were similar in the laboratory, except for adult dietary requirements. The mean number of mature oocytes in the ovaries of M. nevilli, however, was only 15.7 compared with 26.1 in M. xanthomelas.

Animals↗
PubMed1981

Selenium balance in young men during selenium depletion and repletion.

Selenium balance was determined in six young men fed for 45 days a formula depletion diet (33 to 36 micrograms Se/day) then fed for 25 days a repletion of diet (depletion diet plus 200 micrograms Se/day as high-Se wheat or wheat plus tuna fish). After 12 days of adaptation, Se balance during depletion was rather constant at -21 micrograms/day and Se losses in urine and feces were 54 micrograms/day. During repletion, Se balance was +64 micrograms/day for the first 12 days and +25 micrograms/day thereafter and the subjects regained all the Se lost during depletion. If the gastrointestinal absorption of the food Se in North Americans and New Zealanders is similar (80%), young North American men need a dietary Se intake of about 70 micrograms/day to replace losses and maintain body stores.

Adult↗
PubMed1981

Attempts to transmit Anaplasma marginale with Hippobosca rufipes and Stomoxys calcitrans.

Three attempts to transmit anaplasmosis with field collections of Hippobosca rufipes were unsuccessful, despite the fact that the flies had been fed initially on splenectomized cattle acutely infected with Anaplasma marginale. However, 1 out of the 3 attempts, made concurrently with the others, to transmit this organism with Stomoxys calcitrans was successful. The prepatent period was 27 days.

Anaplasmosis↗
PubMed1980

Physiological age determination in female Stomoxys calcitrans Linnaeus (Diptera: Muscidae).

The primary sex organs of female Stomoxys calcitrans consist of a single pair of ovaries, each containing 80-100 polytrophic ovarioles. A natural population of these females can be grouped according to age into different reproductive categories. The technique described below defines these categories and enables one to distinguish between newly-emerged, nulliparous and uniparous females and females that have reproduced twice (biparous) or more (pauciparous).

Animals↗
PubMed1980

The temperature preferences of the motile stages of Stomoxys calcitrans Linnaeus (Diptera: Muscidae).

When adult Stomoxys calcitrans were exposed to a temperature gradient, 66% of them selected temperatures between 20, 1 and 32, 5 degrees C. The larval stages preferred temperatures between 19, 5 and 33, 2 degrees C. Although the differences in the temperature preferences of the different larval stages were not significant, the fully-fed larvae appear to prefer slightly cooler conditions than the feeding stages. The temperature preferences of both the adults and the larvae are not influenced by the temperatures to which the developmental stages of the experimental flies or their previous generations were exposed.

Age Factors↗
PubMed1979

The effect of temperature on the frons width in males of Stomoxys calcitrans Linnaeus (Diptera: Muscidae).

Laboratory experiments established that males of Stomoxys calcitrans, raised at a high temperature (30 degrees C), had frons widths that were very significantly smaller (P=0,01) than those of males raised at a lower temperature (20 degrees C). Thus, although the frons width is apparently controlled genetically, it can also be influenced by temperature. It was also established that temperature acted on the fully-fed 3rd instar larva to affect the adult male frons width.

Animals↗
PubMed1979

Some effects of temperature on the adults, eggs and pupae of Stomoxys calcitrans Linnaeus (Diptera: Muscidae).

Adults could only live and reproduce to their full capacity at temperatures between 20 degrees C and 30 degrees C. At 15 degrees C the females laid no eggs, the adult life span was relatively short and the reproductive capacity of females kept at 35 degrees C was low. The thermal histories of the flies had no apparent effect on their later reactions to temperature in any of the parameters tested. The viability rates of S. calcitrans eggs exposed to temperatures between 10 degrees C and 40 degrees C exceeded 84%, but 45 degrees C was lethal. The optimum temperatures for incubation of the eggs was 30 degrees C. Pupae of S. calcitrans seemed to tolerate temperatures between 20 degrees C and 30 degrees C, but their mortalities increased markedly outside this temperature range. Tests showed that pupal mortalities increased linearly with increasing periods of exposure to a temperature of 15 degrees C.

Animals↗