Effect of Graft and Sexual Hybridization on the Nodulation of Trifolium ambiguum M.B.

Trifolium ambiguum M.B. is a potentially important clover species,but it has not been used widely as a forage legume because itnodulates sparsely or not at all and the nodules formed areusually ineffective. In some compatible grafts of T. hybridumon T. ambiguum effective nodules developed on the roots of thestock. In addition, effective nodulation was obtained on thesexual hybrid between these two species. The investigation dealswith the effectiveness of nodulation of the graft and sexualhybrids and also of the two host species when inoculated withisolates from the graft hybrid, the sexual hybrid, T. hybridum,and from effectively nodulating T. ambiguum.     

Haligena salina: a new marine pyrenomycete

EARRANT, C. A. & JONES, E. B. G., 1986. Haligena salina: a new marine pyrenomycete. Haligena salina sp. Nova (Ascomycotina, Sphaeriales, Halosphaeriaceae) collected on wood from San Juan Island, Washington State, U.S.A., and on reeds from Pisa, Italy is described. The species is compared with Haligena elaterophoraj. Kohlmeyer and species in the genus Remispora Linder.     

Selection against large size in the Sand Martin Riparia riparia during a dramatic population crash

In 1984 breeding Sand Martins declined to 27% of their 1983 numbers at a large colony in Scotland. A population crash of similar magnitude occurred over much of central Scotland and over Britain as a whole. The decline in numbers was probably attributable to severe drought conditions experienced overwinter in the Sahel zone of Africa. There was a significant reduction in the mean keel-length of Sand Martins captured at the main study colony in 1984 compared with individuals measured in both 1982 and 1983, suggesting that selection for small body-size had occurred during the period of high overwinter mortality.     

Expression of Cysteine Proteinases by Metacyclic Promastigotes of Leishmania mexicana

ABSTRACT. The expression of cysteine proteinases by metacyclic promastigotes of Leishmania mexicana was investigated using gelatin polyacrylamide gel electrophoresis. Two prominent bands were detected which distinguished metacyclics from multiplicative promastigotes, lacking detectable cysteine proteinase activity, and amastigotes, with a distinct banding pattern composed of multiple enzymes. A correlation between relative activity of the metacyclic-specific bands and the prevalence of metacyclics was found both during the growth cycle in vitro as metacyclogenesis occurred, and by comparison of stationary phase populations from consecutive subpassages in vitro. Irreversible inhibition of the metacyclic activities using N-benzyloxycarbonyl-phenylalanyl-alanyl diazomethane did not inhibit metacyclic to amastigote transformation in vitro. These activities provide a useful biochemical marker for the metacyclic promastigotes of L. mexicana .     

A Note on a Highly Sensitive Modified ELISA Technique for Rhizobium Strain Identification

A modification of the ELISA technique using a fluorescent substrate is described and comparisons are made between this highly sensitive technique and the conventional ELISA method for investigations of the Rhizobium /legume symbiosis. The technique can be used to detect Rhizobium spp. both from pure culture and from nodules on Trifolium repens , at a concentration of 10⁴ cells/ml. Tests for cross-reactivity indicated that the technique will facilitate a wide range of experiments which require the identification of Rhizobium strains.