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The In vitro Cultivation of Nippostrongylus brasiliensis from the Late Fourth Stage

1967; American Society of Parasitologists; Volume: 53; Issue: 1 Linguagem: Inglês

10.2307/3276634

1937-2345

R. I. Sommerville, Paul P. Weinstein,

Parasites and Host Interactions

A quantitative evaluation has been made of some of the soluble components previously incorporated into media used for the cultivation of Nippostrongylus brasiliensis, with regard to their increasing survival and development of the organisms. A relatively rapid screening procedure was used based on a culture inoculum of small numbers of worms in the late fourth or early fifth stage, derived from the intestine of the rat. In a balanced salt solution containing glucose, juveniles molted to the fifth stage and survived longer than in salt solutions alone. Addition of casein further enhanced survival and worms commenced to develop. Still better results were obtained by addition of a yeast extract to a balanced salt solution containing glucose and casein. Some male worms produced sperm and some females produced oocytes and occasionally eggs. Activity of yeast extract was associated with a dialyzable component. The activity of dialyzed yeast extract could be partially restored by addition of a mixture of amino acids. When infective juveniles of Nippostrongylus brasiliensis (syn. N. muris) are inoculated into media which contain such components as chick embryo extract, serum, and a mixture of vitamins, they develop and many attain the adult stage (Weinstein and Jones, 1956, 1959). Although these adults may be smaller than those in the rat, the usual host of N. brasiliensis, they appear to be otherwise normal. But development in these media is slow, and many juveniles fail to grow beyond stages which are equivalent to those found in the lung of the host. Furthermore, there is a fairly consistent loss of worms during recurrent transfers to fresh media. These considerations made it desirable to use alternative methods whereby the fate of each worm could be determined, and at the same time a more rapid assessment of the value of the components of different media could be made. A modification, described below, of the procedure of Weinstein and Jones (1959) was used, wherein juveniles, primarily in the late fourth stage, were isolated from the intestine of the host and their further growth followed in culture. It had been demonstrated previously that sodium caseinate and yeast extract in a balanced salt solution containing glucose were important nutrients in media used for the cultivation of N. brasiliensis from the first to the fifth stage (Weinstein and Jones, 1956, Received for publication 10 October 1966. * Guest Worker. Present address: Department of Zoology, University of Adelaide, Adelaide, South Australia. 1957). The present study presents a quantitative evaluation of these substances, and some information on the nutritional components which they supply. MATERIALS AND METHODS