Hodgkin JA (1989) Genetics "Early worms."

Hodgkin JA

[Genetics, 1989]

Just over 21 years ago, in October of 1967, Sydney Brenner soaked a culture of hermaphroditic nematodes of the species Caenorhabditis elegans in a solution of ethyl methane sulfonate. A week later, examining their F2 descendants, he noticed a short, "dumpy" animal among the long, thin wild-type worms. The dumpy animal was picked to a separate culture plate and allowed to produce self-progeny, which were also dumpy: it was a true-breeding mutant. The new strain was given the name E1. Crosses with the parental wild-type strain showed that the mutant phenotype was due to a single autosomal recessive mutation - in modern nomenclature, allele e1 of the gene dpy-1.

Schweinfurth U (1983) Ecol Dis "Filarial diseases in Ceylon: a geographic and historical analysis."

Schweinfurth U

[Ecol Dis, 1983]

Medical records concerning filarial diseases in Ceylon date from the account of Davy[1], though there are hints as to the more obvious manifestations in the old chronicles of the country, too. A first survey was conducted in 1912/1913 concentrating on urban areas, followed by a second survey in the 1930s with emphasis on the rural parts. The results displayed a remarkable distribution pattern: Wuchereria bancrofti, the so-called "urban type", concentrated in Galle and Matara towns, whereas Brugia malayi, the "rural type", widespread along the southwest coast from Matara to Negombo, plus isolated pockets in the northwest, central north, east and south. The survey of the 1930s lead to the supposition that the occurrence of B. malayi must have something to do with the distribution of certain water plants, a suspicion later on confirmed in that Pistia stratiotes in particular--but other water plants as well--are essential for the survival of the vector (Taeniorhynchus (Mansonia) uniformis) during its early (submersed) stages of development. A determined effort to remove the water plants from tanks etc. reduced the rural type with encouraging results. At the same time, a combination of factors, in particular the war-time sojourn of masses of troops from Africa, already infected by filarial diseases, in the southwestern coastal areas triggered off an unexpected spread of the urban type out of its early "bridge-heads" in Galle and Matara towns to invade the southwest coastal areas, and, later on, supported by increased population mobility, to advance further inland too. At present, there is no remedy within sight to give some hope to come to grips with this problem as the vector, Culex pipiens fatigans, is ubiquitous and finds suitable breeding grounds practically everywhere. Research into the history of filarial diseases in Ceylon points as far as B. malayi is concerned, to an invasion by a Malayan army under the Kalinga kings during the days of close relations between Ceylon and southeast Asia, i.e. during the 12th and 13th centuries, and as far as W. bancrofti is concerned, a Chinese army, invading the southern coast in the early 15th century, is made responsible. Filarial diseases in Ceylon present a particular interesting case of geomedical research; but inspite of encouraging results in fighting the rural type, i.e. B. malayi, the urban type, W. bancrofti, seems to remain a problem of public health in the island for the forseeable future.