The Influence of NCTC 109, Serum, and Swine Kidney Cell Cultures on the Morphogenesis of Stephanurus dentatus to Fourth Stage, In vitro

Publisher Website
Google Scholar
Abstract
Stephanurus dentatus was grown to advanced parasitic stages in a new static in vitro system, free of bacteria and fungi. Criteria for evaluation were based on anatomical characters of the head, stoma, excretory system, and intestine. Descriptions of these characters and observations on morphogenesis not previously reported from in vivo specimens are given in detail. Development to late fourth stage was obtained in cultures consisting of primary monolayers of swine kidney cells overlaid with the following medium (KW-1S) yeast extract (BBL), 112.5 mg; Bacto-peptone (Difco), 140.65 mg; dextrose (BBL), 140.65 mg; swine serum, 50 ml; NCTC 109, 50 ml; and antibiotics to give a final concentration of 1,000 units penicillin G potassium, 1 mg dihydro-streptomycin, and 10 [mu]g Amphotericin B per ml of medium. When bovine serum was substituted (KW-1) development halted at mid fourth stage. In addition, with both fluid media, the following were observed: only larvae in fourth stage fed on the kidney cell cultures; a definite feeding pattern occurred; larvae fed on rolled cell layers (presumably dead) as well as living cells; digestion and egestion took place, and there was a correlation between feeding behavior and anatomical development of the stoma, excretory system, and intestine. In either medium, without the cell culture, only early fourth stage was attained and yields of this phase of development were reduced to one-fortieth. Media KW-1 and KW-1S evolved from attempts to culture S. dentatus in modifications of Pitts'' and Ball''s (1953) medium, or in NCTC 109 (McQuilkin et al., 1957) used alone or supplemented with calf serum. The prototype cell-free media, one of which was also supplemented with nonliving tissue, had the following effects on development: (1) the most advanced stage attained was early fourth stage; (2) larvae advanced to late parasitic third stage in media supplemented with either NCTC 109 or serum; (3) development proceeded to early fourth stage when both NCTC 109 and serum were present; (4) a more rapid rate of development to third molt and early fourth stage ensued when NCTC 109 and serum were present at concentrations of 50%, each; and (5) although fourth-stage larvae ingested nonliving tissues when available, development was not enhanced.