摘要:

SUMMARYHansenula holstiiis judged to be the most primitive, or ancient, heterothallic species of the genus because it is so nearly exclusively haploid in the vegetative state that the diploid form has never been isolated from nature. This species ferments one sugar, rarely two, and the fermentation is slow. Even thin pellicles are seldom produced, and esters are not synthesized.H. holstiihas the maximum requirement of the genus for vitamins. Its colonies are generally mucoid, and the cells are small. All of these characteristics of haploids contrast with the corresponding characteristics of those more recently evolved diploid yeasts which live independently of trees.H. holstiiandH. capsulata, the latter being the most primitive homothallic species of the genus, live mainly in association with coniferous trees and bark beetles. From the taxonomic area in which these two species occur, a heterothallic and a homothallic line of species evolved into associations with deciduous trees and finally into free living forms. The physiological powers of these two lines increased with succeeding species. Two other lines, starting at the phylogenetic level ofH. holstiiandH. capsulata, developed into complete dependence upon coniferous trees, with concurrent gradual loss of the ability to cause gaseous fermentation. In all four lines the primary evolutionary characteristic was increase in the ratio of diploid to haploid vegetative cells. The proportion of diploid cells increased rapidly in the lines developing toward the free living state, but slowly in the lines developing toward dependence upon conifers. It is thus apparent thatH. holstiiandH. capsulataoccupy important positions in the evolution of the genus.Generally, the more primitive a heterothallic species of yeast is, the more difficult it is to find sexually reactive forms in nature, andH. holstiiis no exception to this rule. However, by mating ascosporic isolates back to their parents through two successive experiments, inbred mating types were obtained which mated abundantly among themselves but not with natural isolates. Although diploid cells are formed in such infinitesimally small numbers by primitive haploid species that diploid colonies are never isolated from nature, they may be produced in the laboratory, and pure ascosporogenous diploid cultures have been produced for the two primitive heterothallic species ofHansenuladiscovered to date.Hansenula holstiiproduces in good yield an extracellular phosphomannan that has interesting and potentially useful properties.

ISSN:0027-5514    

DOI:10.1080/00275514.1960.12024891

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

SUMMARYHansenula angustais a species of yeast associated with deciduous trees and disseminated by bark beetles and fruit flies. It exists in nature predominantly in the haploid form but a small percentage of diploid cells are generally present. Ascospores impart a red color to the colonies when they are 4 to 8 days old, the diploid colonies having a denser color than the haploid colonies because diploid cells of homothallic yeasts generally sporulate sooner and more abundantly than the haploid cells. This species is recommended for classroom demonstration of the following general characteristics of homothallic yeasts which exist in both the haploid and diploid forms: Haploid cells are smaller than diploid. Haploid cells produce conjugation tubes whereas diploids do not, and the asci formed from haploids are smaller and are conjugated, while those produced by diploids are larger and are unconjugated. The haploid cells diploidize at a slow rate while growing vegetatively, but the diploids evidently must sporulate in order to return to the haploid state. Either form may be derived and maintained in practically pure state by selection and lyophilization.

ISSN:0027-5514    

DOI:10.1080/00275514.1960.12024892

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

SUMMARYA new species of smut found infecting soybeans is described asMelanopsichium missouriense.The soybean pod is consumed, and a gall of hard, charcoal-like consistency is formed. Chlamydospores, resembling as to spore form, echinulations, etc., those formed in the galls, develop readily in culture. Chlamydospores germinate forming promycelia bearing sporidia both laterally and terminally.

ISSN:0027-5514    

DOI:10.1080/00275514.1960.12024893

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

SUMMARYLeptodiscus terrestrisrequires light for the formation of both fruiting structures and conidia. The fruiting structure is meristogenous in origin. Branches are produced from an initial, multinucleate, hourglass-shaped cell. Sporogenous cells develop at the apex of each branch, and these in turn produce more sporogenous cells, eventually forming a thin, saucer-shaped fruiting structure.The spores first appear as small protuberances on the inner edge of the sporogenous cells. These protuberances enlarge and elongate and as they develop, they appear to be attached to the sporogenous cells by a very short stalk. This stalk disappears when the spores mature. When the spores reach their mature size, the setae are formed. The seta on the upper end of the spore develops at the point of greatest curvature toward the concave side, and the seta on the lower end develops at the edge of the slightly flattened surface near the concav side of the spore. One crop of spores is produced by the sporogenous cells each day. Spores are held together in a head by a mucilagenous substance.When the spores are in the head, the setae are folded back against the spore wall on the concave side. When the mucus is dissolved, the setae unfold and expell the spores outward with considerable force. The same mechanism of spore dispersal also appears to occur inMenispora tortuosa, a fungus with setulate conidia similar to those ofL. terrestris.

ISSN:0027-5514    

DOI:10.1080/00275514.1960.12024894

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

SUMMARYNine species ofMorchella, and a number of strains of several of these species, have been grown in submerged culture.Morchellain submerged culture is quite omnivorous so far as its carbohydrate and nitrogen requirements are concerned.The mycelium develops the piquant flavor of the sporocarp.In submerged culture, using a standard nutrient formula, the following species and strain differences are distinguishable: rate of growth, habit of growth, development of discrete mycelial spheres, color of spheres, flavor of mycelium, intensity of flavor, color of the supernatant liquor, and odor of the effluent air.The mycelium will grow at temperatures as low as 36°F, but growth is much slower than at 55 to 70°F, a range which appears to be optimum.A production of 10–25 g (dry wt.), of mycelium per liter of nutrient medium may be expected.The mycelium may be utilized fresh, fresh-frozen, dry, powdered, or as a flavor concentrate.At least one strain has been shown to be adaptable to commercial production.

ISSN:0027-5514    

DOI:10.1080/00275514.1960.12024895

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1960.12024896

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

SUMMARYGrowth ofPoria ambiguaBres. was improved by the addition of yeast extract and other natural materials to a basal medium of mineral salts, dextrose, casein hydrolysate, purine and pyrimidine bases, and B vitamins. Light reduced growth but was required for formation of basidiospores. The addition of natural materials largely eliminated the inhibitory action of light on growth, and with the addition of sufficient natural material growth in the light exceeded growth in the dark. On rich media, spore production was reduced or eliminated. Local inhibition of growth on rich media permitted spore production to occur.P. ambiguais very sensitive to light. Exposure of inoculum to light for a period of minutes affected growth and spore production. The light stimulus was transmitted into mycelium formed later in the dark. Some isolates prepared from single basidiospores formed spores on nutritionally poor media. Isolates grown from single hyphal tips varied in ability to form basidiospores; one equalled in potency the stock culture used in this investigation.To explain the results, three growth substances are assumed as follows: (x) formed in the light required for reproduction but involved in vegetative growth also; (y) formation interfered with by light, required for vegetative growth; (z) formation favored by light, limiting for growth in the dark in the presence of luxus amounts of (y).

ISSN:0027-5514    

DOI:10.1080/00275514.1960.12024897

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

SUMMARYA new fungus,Enterobryus oxidi, in the hindgut of the millipedOxidus gracilis(Koch), is described and illustrated. Distinctly wider and narrower hyphae are formed, and four types of spores were observed. This species appears to be quite different fromEnterobryus flavusMaessen, described from the same host in Europe.

ISSN:0027-5514    

DOI:10.1080/00275514.1960.12024898

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1960.12024899

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

SUMMARYThe well known decay of bald cypress is now known to be caused by the newly describedStereum taxodiiLentz&McKay. It is similar toS. sulcatumBurt, common on spruce and fir in the Rocky Mountain forests and on eastern hemlock in Pennsylvania, New York, and other areas.There are distinct differences between these twoStereumspecies in host relationships, in structure of basidiocarp, in type of decay, and in cultural characteristics.S. taxodiiis a top rot fungus, apparently gaining entrance through branch stubs or broken tops, whereasS. sulcatumis a butt rot organism. The former causes a distinctive type of rot, which in typical stages consists of rather large pockets of advanced decay scattered through the heartwood in a uniform and characteristic fashion. The latter typically causes a white stringy rot, which in some stages resembles a rather irregular white pocket rot.Growth and temperature relationships are quite different in the two species; andS. sulcatumhas a conidial stage and no chlamydospores, whereasS. taxodiihas no conidial stage but numerous chlamydospores.S. sulcatumgives a strong oxidase reaction, whereasS. taxodiihas a very weak oxidase reaction. Detailed descriptions are given for both the species.

ISSN:0027-5514    

DOI:10.1080/00275514.1960.12024900

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor