Volume 52, Issue 3
September 1960, pages 73-109
pp 73-90 September 1960
pp 91-102 September 1960
1. The early development ofStomopneustes variolaris Agassiz has been traced from artificially fertilized eggs up to the end of the fourth day.
2. The details of segmentation and gastrulation are given. The blastocœl is traceable even from the four-celled stage.
3. The larval skeleton resembles the Echinometrid type, forming a compound basket structure.
4. Affinities of the form based on larval structure are discussed. The form shows close resemblance to Echinometridæ, which are presently grouped under a different suborder.
pp 103-109 September 1960
Highly active protopectinase and polygalacturonase (PG) enzymes were secreted byPenicillium expansum Link. on 2·5% decoction of lucerne, pectin asparagin and modified Czapek’s media. Ammonium nitrate was found to be a better nitrogen source for the secretion of pectic enzymes than asparagin or sodium nitrate. Best secretion of protopectinase was in cultures after 4 days incubation at 20° C.
Pectin-esterase, when tested at 6·2 pH, was found to be of negligible activity in 4 days old cultures of the fungus.
Protopectinase and polygalacturonase (PG) were found to be adaptive enzymes which were not produced in absence of pectic substances.