Carotenoid Pigments of Mycobacterium kansasii

Partitioned between aqueous methanol and petroleum ether, the unsaponifiable pigments of Mycobacterium kansasii were all epiphasic. Thin-layer chromatography of these carotenoids showed that M. kansasii formed at least nine pigments. These pigments were identified by their chromatographic properties and spectral characteristics as phytoene, zeta-carotene, neurosporene, lycopene, leprotene, gamma-carotene, delta-carotene, alpha-carotene, and beta-carotene. Three additional pigmented spots on thin-layer chromatography found in trace amounts were possibly degradation products of the major carotenoids.     

Nature and Distribution of Carotenoid Pigments in Astasia ocellata

SYNOPSIS. The pigments synthesized by Astasia ocellata include α- and ε-carotene, 4-keto-β-carotene (echinenone), and 4,4'-diketo-β-carotene (canthaxanthin); 4-keto-α-carotene, accounting for about half the pigment in the cells, was tentatively identified; a strongly adsorbed keto-carotenoid, accounting for 25% of the pigments and bearing some similarities to astacin, polytomaxanthin and phoenicoxanthin, was also found.     

Division spindle and centrosomal plaques during mitosis and meiosis in some Ascomycetes

The behaviour of the division spindle and centrosomal plaques is described in four species of Ascomycetes (Ascobolus immersus, Ascobolus stercorarius, Podospora anserina and Podospora setosa) studied by light and electron microscopy. Two unique features of the kinetical apparatus were observed: presence of centrosomal plaques and intranuclear location of the spindle. In all types of mitoses (mycelium, crosier and postmeiotical mitosis) the apparatus is structurally identical to that found in meiosis. The centrosomal plaques, present in all divisions, are always contiguous with the nuclear envelope and never show centrioles similar to those commonly found in Metazoa and Protozoa. During metaphase and anaphase the plaque is constituted of two zones situated on each side of the nuclear envelope: an electron opaque outer zone and inner one less opaque in which most of the microtubules end. In Podospora the outer zone appears in sections as consisting of two dark layers separated by a clear one. Two dispositions of plaques are possible: either they are entirely contiguous with the nuclear envelope (Ascobolus) or only partially so, the remainder being perpendicular to the nuclear envelope (Podospora). — The localisation of the plaques in the ascus was determined by light and electron microscopy. The nuclear envelope was shown to remain intact during division. It was possible to observe that the sporal wall of each spore originated from the same unique double membrane formed in the ascus during the meiotic second division and postmeiotical mitosis. This fact is of genetical interest for the study of morphological and physiological characters of the spores.     

Dependence of Pepper Fruit Colour on Basic Pigments Ratio and Expression Pattern of Carotenoid and Anthocyanin Biosynthesis Genes

Russian Journal of Plant Physiology - Fruit biochemical analysis of four pepper (Capsicum annuum L.) cultivars, contrasting in immature and ripe fruit colour, was performed, and chlorophylls,...     

Ascomycetes from Northern Thailand

12 pyrenomycetes and 22 discomycetes are recorded from the Chiang Mai Province of Northern Thailand. 25 species are new to Thailand. Pulvinula anthracobia Schum. is described as new, and Xylaria scopiformis (Mont, ex Joly) Schum. comb. nov. is proposed.     

Pteridophytic features in some Lower Carboniferous seed megaspores

Some Lower Carboniferous seed megaspores have triradiate sutures–unequivocal evidence of their being arranged in a tetrahedral configuration. This type of tetrad arrangement is unknown in the ovules of modern gymnospermS. Some of the fossil tetrads consist of one large functional megaspore and three smaller abortive spores attached at the apex of the large one. All four spores have an exinous covering.
Spores arranged in tetrahedral tetrads, and hence with triradiate sutures, are characteristic of many modern and fossil free-sporing pteridophyteS. In possessing this feature the fossil seed megaspores are more similar to the spores of these pteridophytes than to the megaspores of modern gymnosperms.     

Ascomycetes on Myrica gale in Sweden

The Ascomycete flora on Myrica gale has been investigated, mainly on the basis of Swedish material. It is found to be largely host specific. Four Discomycetes and nine Pyrenomycetes s. lat. are recorded as true, ± exclusive Myrica fungi; ten plurivorous Pyrenomycetes have occasionally been met with. The mycoflora on Myrica gale seems to be of a rather recent origin, composed of fairly modern species. Six new names are published: Gibbera gemmarum sp. nov., G. minutissima sp. nov., Melanomma myricae sp. nov., Semisphaeria sigmundii gen. nov. et sp. nov., Stomiopeltis myricae sp. nov., and Trichopezizella myricae comb. nov.     

Molecular Genetics of Heterokaryon Incompatibility in Filamentous Ascomycetes

Filamentous fungi spontaneously undergo vegetative cell fusion events within but also between individuals. These cell fusions (anastomoses) lead to cytoplasmic mixing and to the formation of vegetative heterokaryons (i.e., cells containing different nuclear types). The viability of these heterokaryons is genetically controlled by specific loci termed het loci (for heterokaryon incompatibility). Heterokaryotic cells formed between individuals of unlike het genotypes undergo a characteristic cell death reaction or else are severely inhibited in their growth. The biological significance of this phenomenon remains a puzzle. Heterokaryon incompatibility genes have been proposed to represent a vegetative self/nonself recognition system preventing heterokaryon formation between unlike individuals to limit horizontal transfer of cytoplasmic infectious elements. Molecular characterization of het genes and of genes participating in the incompatibility reaction has been achieved for two ascomycetes, Neurospora crassa and Podospora anserina. These analyses have shown that het genes are diverse in sequence and do not belong to a gene family and that at least some of them perform cellular functions in addition to their role in incompatibility. Divergence between the different allelic forms of a het gene is generally extensive, but single-amino-acid differences can be sufficient to trigger incompatibility. In some instances het gene evolution appears to be driven by positive selection, which suggests that the het genes indeed represent recognition systems. However, work on nonallelic incompatibility systems in P. anserina suggests that incompatibility might represent an accidental activation of a cellular system controlling adaptation to starvation.