Invasive Pulmonary Fungal Infections in Cystic Fibrosis

Invasive pulmonary mycosis is after allergic bronchopulmonary aspergillosis (ABPA) a frequent and severe complication of CF lung disease. Among CF caregivers, there is an insecurity when and how to treat infections of the lung parenchyma caused by different fungi in patients with CF. This case series provides a multicenter experience on diagnostic, manifestation, and treatment of non-ABPA cases of pulmonary. Non-ABPA cases of pulmonary mycoses in patients with CF have been collected from the CF Centers in Berlin, Essen, Worms, Frankfurt (Germany), Leeds (UK), and Barcelona (Spain). Non-ABPA was defined as total serum IgE level <500 kU/L. Scedosporium and Lomentospora species seem to be more virulent in patients with CF and have been successfully treated with triple antifungal drug regimens in several cases. Rare fungi including yeasts can have pathogenic potential in CF. In this series, antibiotic treatment failure was the main indicator for the initiation of antifungal treatment. For an early and effective treatment of pulmonary mycoses in CF, the identification of biomarkers and of risk factors beyond antibiotic treatment failure is crucial and urgently needed. Furthermore, treatment efficacy studies are necessary for the different causative agents of these infections.     

An in vitro whole plant selection system: paraquat tolerant mutants in the fern Ceratopteris

Summary A whole plant selection system using the haploid gametophyte generation of the fern Ceratopteris richardii has been developed to select for mutations that confer resistance or tolerance to various selection pressures. The expression of the mutations can be analyzed and characterized in both the haploid gametophyte and diploid sporophyte generations. Genetic analyses are facilitated by the fern's rapid life cycle and the ease of manipulating the gametophyte generation. Selection for tolerance to the herbicide paraquat has yielded two mutants which have an increased tolerance to the herbicide in both the gametophyte and sporophyte generations. Both mutants exhibit single nuclear gene inheritance patterns and appear to be closely linked or allelic.     

Structural diversity of the major surface antigen of Plasmodium falciparum merozoites.

The structures of the major merozoite surface antigen of Plasmodium falciparum and the gene encoding it were indistinguishable for the Wellcome strain and the Thai clone T9/94 but different for clones T9/96, T9/98, and T9/101. The central portion of the gene is subject to the greatest variation in structure. The protein from all five lines was found to be posttranslationally modified by covalent addition of both carbohydrate and fatty acid.     

Sequence analysis of the Clostridium stercorarium celZ gene encoding a thermoactive cellulase (Avicelase I): Identification of catalytic and cellulose-binding domains

Summary The nucleotide sequence of the celZ gene coding for a thermostable endo--1,4-glucanase (Avicelase I) of Clostridium stercorarium was determined. The structural gene consists of an open reading frame of 2958 by which encodes a preprotein of 986 amino acids with an M_r of 109000. The signal peptide cleavage site was identified by comparison with the N-terminal amino acid sequence of Avicelase I purified from C. stercorarium culture supernatants. The recombinant protein expressed in Escherichia coli is proteolytically cleaved into catalytic and cellulose-binding fragments of about 50 kDa each. Sequence comparison revealed that the N-terminal half of Avicelase I is closely related to avocado (Persea americana) cellulase. Homology is also observed with Clostridium thermocellum endoglucanase D and Pseudomonas fuorescens cellulase. The cellulose-binding region was located in the C-terminal half of Avicelase I. It consists of a reiterated domain of 88 amino acids flanked by a repeated sequence about 140 amino acids in length. The C-terminal flanking sequence is highly homologous to the non-catalytic domain of Bacillus subtilis endoglucanase and Caldocellum saccharolyticum endoglucanase B. It is proposed that the enhanced cellulolytic activity of Avicelase I is due to the presence of multiple cellulose-binding sites.     

Diminished glucocorticoid tonus in obese strain (OS) chickens with spontaneous autoimmune thyroiditis: increased plasma levels of a physicochemically unaltered corticosteroid-binding globulin but normal total corticosterone plasma concentration and normal glucocorticoid receptor contents in lymphoid tissues

Obese strain (OS) chickens afflicted with spontaneous autoimmune thyroiditis (SAT) display several signs of a general immune dysbalance, some of which may be related to altered endocrine mechanisms such as the glucocorticoid tonus. The latter is the combined result of corticosterone (CN) production, metabolism as well as excretion, and the binding of CN to corticosteroid binding globulin (CBG) and glucocorticoid receptors (GR). The present study deals with the comparative investigation of these parameters in OS and normal White Leghorn (NWL) chickens. The results obtained with radioimmunoassay for CN and radioligand saturation assays for plasma CBG as well as GR in the thymus were as follows: (1) both OS and NWL have equal total CN levels; (2) however, OS chickens exhibit elevated CBG levels, whereas the physicochemical parameters (equilibrium affinity, specificity spectrum) of CBG were equal in OS and NWL; (3) the GR capacities and affinities were equal in both OS and NWL throughout development until thymic involution. Similarly, the specificity, affinity, and sedimentation behaviour were equal in OS and NWL. (4) Furthermore, no differences were found in the response of OS and NWL splenocytes to the suppressive effect of glucocorticoids in vitro, also excluding postreceptor alterations at the cellular level in the OS. From these findings we conclude that the increased CBG levels, which are not compensated for by either increased CN plasma levels or by increased receptor capacities or affinities in lymphatic organs, represent a diminished glucocorticoid tonus in OS chickens. This may have immunoregulatory consequences which, in turn, may contribute to the development of SAT.     

The dissociation of the extracellular hemoglobin of Tubifex tubifex at extremes of pH and its reassociation upon return to neutrality

The dissociation of the extracellular hemoglobin of Tubifex tubifex at alkaline and acid pH, and its reassociation upon return to neutral pH, was investigated using gel filtration, ultracentrifugation, and polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE). Tubifex hemoglobin dissociated at pH above 8 and below 6; both dissociations appeared to be equilibrium processes. The extent of dissociation increased as the pH moved away from neutrality; although dissociation was virtually complete at pH 11, its extent at acid pH did not exceed 50–60% at pH 4. Ca(II), Mg(II), and Sr(II) cations over the range 1–100 mm decreased the extent of the dissociation only at alkaline pH. The visible absorption spectrum of the oxyhemoglobin remained unaltered in the pH range 4–9. At more extreme pH, it changed with time, altering irreversibly to that of the aquo ferri form. Gel filtration of the hemoglobin at both extremes of pH showed that it dissociated into two heme-containing fragments; one consisting of subunit 1 (M_r ~ 17,000) and the other containing subunits 2, 3, and 4 of the hemoglobin (M_r ~ 60,000). Upon return to neutral pH, the dissociated fragment reassociated to the extent of 50 to 80% to whole hemoglobin molecules. The reassociation decreased with increase in alkaline pH, and with decrease in acid pH to which the hemoglobin had been exposed; it increased in the presence of Ca(II), Sr(II), and Mg(II) only subsequent to dissociation at alkaline pH. The SDS-PAGE patterns, gel-filtration elution volumes, and α-helical contents, determined from circular dichroism at 222 nm, of the reassociated whole molecules were identical to those of the native hemoglobin.     

Variation in propensity to defend by reproductive gall morphs in two species of gall-forming thrips

Summary.Six species of Australian phleaothripine gall forming thrips on Acacia have two morphs. One morph, referred to as a soldier, has reduced antennae and wings and greatly enlarged fore femora, which are thought to be adaptations for gall defence. For most species, female soldier morphs have reduced reproductive output relative to dispersing females and these species have been regarded as eusocial. We examine defensive behaviour of soldier morphs using in situ presentation of gall invading kleptoparasites. We show that the gall-morph of Oncothrips tepperi attack kleptoparasites more often (N=87 interactions, n = 11 attacks) than does the gall-morph of Oncothrips morrisi (N = 231, n = 1). This difference in proclivity for defence is coincident with a lower reproductive output by the gall-morph in O. tepperi compared to O. morrisi. Our results also show an almost complete absence of attack behaviour by the gal l-morph of O. morrisi. Lastly, we show that there is no difference in proclivity for defence between soldier and foundress morphs of O. tepperi. These observations taken together call into question the suitability of the term 'soldier' as applied to the gall-morph of the gall-forming thrips of Australia.