[Carotenoids and fatty acids in red yeasts Sporobolomyces roseus and Rhodotorula glutinis]. / Karotinoidy i zhirnye kisloty v krasnykh drozhzhakh Sporobolomyces roseus i Rhodotorula glutinis.

Rhodotorula glutinis and Sporobolomyces roseus, grown under different aeration regimes, showed differential responses in their carotenoid content. At higher aeration, the concentration of total carotenoids increased relative to biomass and total fatty acids in R. glutinis, but the composition of carotenoids (torulene > beta-carotene > gamma-carotene > torularhodin) remained unaltered. In contrast, S. roseus responded to enhanced aeration by a shift from the predominant beta-carotene to torulene and torularhodin, indicating a biosynthetic switch at the gamma-carotene branch point of carotenoid biosynthesis. The overall levels of total carotenoids in highly aerated flasks were 0.55 mol-percent and 0.50 mol-percent relative to total fatty acids in R. glutinis and S. roseus (respectively), and 206 and 412 microg g(-1) dry weight (respectively).

The vacuole as central element of the lytic system and sink for lipid droplets in maturing appressoria of Magnaporthe grisea.

Histochemical and ultrastructural studies were carried out on a wild-type strain (Guy11) and a melanin-deficient mutant (buf1) of the rice-blast pathogen, Magnaporthe grisea (= Pyricularia oryzae), in order to investigate the destination of lipid storage reserves during appressorium development. Lipid droplets were abundant in conidia and were mobilised upon germination, accumulating in the appressorial hook which developed at the tip of each germ tube. Following the formation of a septum at the base of the nascent appressorium, one or a few closely appressed central vacuoles became established and were observed to enlarge in the course of appressorium maturation. On unyielding artificial surfaces such as glass or plastic, appressoria matured to completion within 36-48 h, by which time the enlarged vacuole filled most of the inside volume of the appressorium. Light and transmission electron microscopical observations revealed that the lipid droplets entered the vacuole by autophagocytosis and were degraded therein. Histochemical approaches confirmed the vacuole as the key lytic element in maturing appressoria. Endocytosis of a vital dye, Neutral Red, progressed via endosomes which migrated into the vacuole and lysed there, releasing their dye content into the vacuolar lumen. Furthermore, activity of the lysosomal marker enzyme, acid phosphomonoesterase, was strongly localised in the vacuole at all stages of appressorium maturation. It is therefore envisaged that vacuoles are involved in the degradation of lipid storage reserves which may act as sources of energy and/or osmotically active metabolites such as glycerol, which generate the very high turgor pressure known to be crucial for penetration of hard surfaces. On softer surfaces such as onion epidermis, appressoria of M. grisea were able to penetrate before degradation of lipid droplets had been completed.

The origin and spread of the new daisy rust in Britain.

Since 1997, wild and cultivated daisies in Britain and other European countries have been suffering from a rust fungus epidemic that menaces the future cultivation of horticultural varieties. The causal fungus was first discovered in Australia 100 years ago and may have evolved there from another rust fungus on daisies previously introduced from Europe. At present, ornamental daisies can be grown successfully only when protected by fungicide sprays.

MAP kinase and protein kinase A-dependent mobilization of triacylglycerol and glycogen during appressorium turgor generation by Magnaporthe grisea.

Magnaporthe grisea produces an infection structure called an appressorium, which is used to breach the plant cuticle by mechanical force. Appressoria generate hydrostatic turgor by accumulating molar concentrations of glycerol. To investigate the genetic control and biochemical mechanism for turgor generation, we assayed glycerol biosynthetic enzymes during appressorium development, and the movement of storage reserves was monitored in developmental mutants. Enzymatic activities for glycerol generation from carbohydrate sources were present in appressoria but did not increase during development. In contrast, triacylglycerol lipase activity increased during appressorium maturation. Rapid glycogen degradation occurred during conidial germination, followed by accumulation in incipient appressoria and dissolution before turgor generation. Lipid droplets also moved to the incipient appressorium and coalesced into a central vacuole before degrading at the onset of turgor generation. Glycogen and lipid mobilization did not occur in a Deltapmk1 mutant, which lacked the mitogen-activated protein kinase (MAPK) required for appressorium differentiation, and was retarded markedly in a DeltacpkA mutant, which lacks the catalytic subunit of cAMP-dependent protein kinase A (PKA). Glycogen and lipid degradation were very rapid in a Deltamac1 sum1-99 mutant, which carries a mutation in the regulatory subunit of PKA, occurring before appressorium morphogenesis was complete. Mass transfer of storage carbohydrate and lipid reserves to the appressorium therefore occurs under control of the PMK1 MAPK pathway. Turgor generation then proceeds by compartmentalization and rapid degradation of lipid and glycogen reserves under control of the CPKA/SUM1-encoded PKA holoenzyme.

Histochemical and ultrastructural characterization of vacuoles and spherosomes as components of the lytic system in hyphae of the fungus Botrytis cinerea.

An integrated approach to acid phosphatase (EC 3.1.3.2) histochemistry by the azo-dye and lead-capture ('Gomori') methods in phosphate-starved hyphae of the fungus Botrytis cinerea revealed strikingly different patterns of localization of activity staining. Reaction product formed with the azo-dye method was found in numerous small organelles (<0.5 microm diameter), which also accumulated the lipophilic dye Nile Red and mislocalized the formazan indicating mitochondrial succinate dehydrogenase activity. Such small organelles were stained only weakly and sporadically with the lead-capture method; instead, lead phosphate deposits were produced mainly in large vacuoles (up to 2.5 microm diam.), similar to those accumulating the vital dye Neutral Red. Additionally, acid phosphatase activity was detected in apical secretory vesicles with the lead-capture method but not with the azo-dye method. Ultrastructural studies by transmission electron microscopy confirmed the presence of large vacuoles which showed evidence of autophagic activity, and of small moderately osmiophilic organelles. The latter are considered to be spherosomes rather than lysosomes because of their weak reaction with the lead-capture method and their high lipid content. It is suggested that their apparently strong reaction with the azo-dye method is caused partly by false localization due to the lipophilic nature of the reaction product.

Pollen identification.

LEARNING OBJECTIVES: The purpose of this review is to introduce the reader to a systematic approach to categorizing pollen types. This will enable the reader to recognize pollen characteristics of the most common botanical sources and determine the relevant contributors to the local aeroallergen burden. DATA SOURCES: Allergenic plant and pollen atlases for pollen characteristics, allergy texts for procedures and overviews, and relevant reviews from the English medical literature (1985 to present). RESULTS: By applying a visual gestalt utilizing grain number, size, shape, surface structures, and internal detail, one is able to identify pollen source to the appropriate botanical taxonomic level. Identification may be possible only to the family or order, but most frequently to the genus, and occasionally to the species. CONCLUSIONS: Outdoor sampling allows the identification of aeroallergen burden in a locale. In conjunction with field work, the relevant sources can be identified as well as time of pollination. This allows the physician to correlate symptoms with exposure and relevant sensitization.

Immunotherapy with allergens.

Allergen immunotherapy has been shown to be efficacious in numerous studies for the clinical indications of allergic asthma and rhinitis, as well as hymenoptera venom hypersensitivity. How allergen immunotherapy improves clinical symptoms is still not entirely clear. Decreases in specific IgE follow a complex cascade of effects: a shifting of the cytokine milieu from T(H)2 to T(H)1 predominance, with resultant decrease in interleukin 4, decreased recruitment and activation of eosinophils, and decreased proliferation of mast cells. Allergen exposure has a lessened ability to stimulate an inflammatory cell response, with decreased target organ hyperreactivity. Since allergen immunotherapy is not without risk, the decision needs to be made whether injection therapy is safe and provides benefit not achievable by medical management. The continued clarification of optimal allergen concentrations through careful studies of standardized extracts will allow better control of adverse events by limiting unnecessarily potent mixtures.

Mugwort and sage (Artemisia) pollen cross-reactivity: ELISA inhibition and immunoblot evaluation.

BACKGROUND: Plants of the genus Artemisia are a source of fall allergic symptoms, particularly in the western United States. Studies have characterized the allergens in one of the major species (A. vulgaris) but currently there are no cross-reactivity data on the major United States species. OBJECTIVE: The purpose of this study was to investigate the in vitro cross-reactivity among nine Artemisia species: A. frigida, A. annua, A. biennis, A. filifolia, A. tridentata, A. californica, A. gnaphalodes, A. ludoviciana, and A. vulgaris. METHODS: The cross-reactivity was demonstrated with the use of enzyme-linked immunosorbent assay (ELISA) inhibitions and immunoblotting techniques utilizing a serum pool from patients allergic to Artemisia species. RESULTS: The enzyme-linked immunosorbent assay inhibitions revealed strong cross-reactivity among all nine species with A. biennis and A. tridentata being two of the strongest inhibitors. The polyacrylamide gel electrophoresis showed a great deal of similarity in the bands among the nine species. The nitrocellulose blots showed similar IgE binding patterns among the Artemisia species with strong inhibition among all nine extracts. CONCLUSIONS: These data all demonstrate very strong in vitro cross-reactivity among the nine Artemisia species studied. Such data have significant clinical relevance, suggesting that a single Artemisia species may be sufficient for allergy skin testing and formulation of immunotherapy extracts.