Euphorbia Ingens Research Articles

Pichia euphorbiae sp. nov., a new haploid heterothallic yeast species.

Representatives of an undescribed, haploid, heterothallic yeast species, Pichia euphorbiae, have been recovered from insect-infested specimens of Euphorbia ingens. The new species is considered to be another representative of the apparently related group of heterothallic species, comprising Pichia rhodanensis, Pichia wickerhamii, Pichia veronae, Pichia amylophila, Pichia mississippiensis and Pichia meyerae. While no mating response was observed in interspecific mixtures of the mating types of the new species with the mating types of the first five mentioned species, a sexual response, manifested by the formation of non-sporulating zygotes, was nevertheless detected with the mating types of P. meyerae. Prototrophic hybrids obtained by crossing auxotrophic mutants of the mating types of P. euphorbiae and P. meyerae were found to be only partial recombinants. A description of the new species is given.

Hansenula euphorbiaphila sp. nov., a new, diploid heterothallic yeast species.

Strains of an undescribed, diploid heterothallic yeast species, Hansenula euphorbiaphila, were recovered from material of a moribund, insect-infested specimen of Euphorbia ingens in the Groblersdal (Transvaal, South Africa) area. The new species shows some agreement with the conifer-associated taxa cited as Hansenula bimundalis var. bimundalis and Hansenula bimundalis var. americana. A description of the new species is given.

On the active principles of the spurge family (Euphorbiaceae). IV. Skin irritant and tumor promoting diterpene esters from Euphorbia ingens E.Mey.

The irritant and tumor-promoting principles of the latex of Euphorbia ingens E. Mey have been isolated together with several nonirritant compounds. The Euphorbia factors I1, I5, and I6 are esters of ingenane-type poly-functional diterpene alcohols. Euphorbia factor I1 is characterized as the 3-hexadecanoate of the polyfunctional parent alcohol ingenol and Euphorbia factor I6 as the 3-deca-2.4.6-trienoic acid ester of ingenol. Euphorbia factor I5 is the 16-angelate-3-deca-2.4.6-trienoate of 16-hydroxyingenol. Nonirritant diterpenes of the latex are I2, the ingenol-20-hexadecanoate - an isomer of Euphorbia factor I1 - and I4, the 3.7.12-triacetate-8-nicotinate of the macrocyclic lathyrane-type polyfunctional diterpene alcohol ingol. The diterpene alcohols ingenol and 16-hydroxyingenol are inactive as irritants and tumor promoters of mouse skin. Compared to croton oil factor A1 (TPA), the Euphorbia factor I1 exhibits about 1/10 of the irritant and tumor-promoting activity in mouse skin. I1 shows no reasonable tumorigenic activity. Compared with I1, Eupohorbia factors I5 and I6 are more potent irritants and less potent tumor promoters.

Pichia meyerae, a new, sexually agglutinating, heterothallic, diploid yeast species.

Eight diploid yeast strains, representative of an undescribed, sexually agglutinating, heterothallic Pichia species, have been recovered from insect infestations of Euphorbia ingens in South Africa. A description of the new species, Pichia meyerae, is given. Mating responses were not detected in interspecific mixtures of the mating types of Pichia meyerae and those of Pichia rhodanensis, Pichia wickerhamii, Pichia amylophila and Pichia mississippiensis.

Pichia kodamae sp. nov., a new homothallic yeast species.

Four strains, representative of an undescribed species of Pichia, have been recovered from insect infestations of Euphorbia ingens in South Africa. A description of the new species, Pichia kodamae, is given. The type strain of Pichia kodamae was found not to hybridize with strains of Pichia pini, Pichia methanolica and Pichia cellobiosa.