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Biomedical subjects

A R Barr

Publications and source records attributed to A R Barr.

At least 55 records · Page 3Linked to original sources
PubMed1975

Ecology of California encephalitis viruses on the Del Mar Va Peninsula. II. Demonstration of transovarial transmission.

The high rate of Keystone virus recovery from Aedes atlanticus collected in 1971 and 1972 suggested that these mosquitoes might be emerging infected. To demonstrate the suspected transovarial transmission of this virus, developmental stages of A. atlanticus were collected from the field. Larvae were identified and pooled for virus isolation in suckling mice. Pupae were allowed to emerge in the laboratory, then were segregated by sex and pooled for virus isolation. Keystone virus was recovered from larvae, reared males and reared females, demonstrating transovarial transmission of the Keystone strain of California encephalitis by A. atlanticus.

Aedes↗
PubMed1967

Occurrence and distribution of the Culex pipiens complex.

Culex pipiens is the most widely distributed species of mosquito in the world, the typical form being found in temperate regions and the subspecies, fatigans, in the tropics. Fatigans is morphologically and biologically uniform in different geographical regions, whereas C. p. pipiens is very variable. Where the two forms come into contact, hybrid swarms occur. The only clear distinction between the two forms is in the nature of the male genitalia.Molestus should not be considered to be distinct from pipiens; the only good criterion for the taxonomic recognition of molestus is that it is autogenous.The ancestral form is probably pipiens, which arose from a stem from the Ethiopian region. It probably colonized the northern temperate region fairly slowly, giving much variation between populations. Fatigans appears to have arisen from southern pipiens populations. Molestus seems to be an ecological race of pipiens which develops wherever the proper selective influence acts.

Animals↗
PubMed1965

The inheritance of yellow-larva and ruby-eye in Culex pipiens.

It has been suggested that mosquito vectors of filariasis and other diseases might be controlled by genetic methods. This is not yet possible because of the lack of genetic information concerning the vector species. The present study describes the development of a marker strain which is being used to study genetic control.Two spontaneous mutants of Culex pipiens are described, one for the first time. Ruby-eye (ru) is an autosomal recessive in linkage group 2. It is completely penetrant and completely expressed. It is evident in later instar larvae, pupae, and adults. Yellow-larva (y) is an autosomal recessive, sometimes behaving as a partial dominant, and is also in linkage group 2. It is evident in late fourth-instar larvae and pupae and is generally associated with lengthened larval development. Ruby-eye and yellow-larva are occasionally seen in collections from the field. The frequency of crossing over between ru and y differs significantly among progenies and also between the sexes, the median values being 17% in males and 24% in females.

Culex↗