The human exosome: an autoantigenic complex of exoribonucleases in myositis and scleroderma

The anti-PM/Scl autoantibodies are known to characterize a subset of autoimmune patients with myositis, scleroderma (Scl), and the PM/Scl overlap syndrome. The major autoantigens that are recognized by anti-PM/Scl autoantibodies are designated PM/Scl-100 and PM/Scl-75. These autoantigens have been reported to associate into a large complex consisting of 11 to 16 proteins and to play a role in ribosome synthesis. Recently, it was discovered that the PM/Scl complex is the human counterpart of the yeast (Saccharomyces cerevisiae) exosome, which is an RNA-processing complex consisting of 11 3' → 5' exoribonucleases. To date, 10 human exosome components have been identified, although only some of these were studied in more detail. In this review, we discuss some recent advances in the characterization of the PM/Scl complex.     

Evidence for diet partitioning among three coexisting native freshwater fishes in South Africa's Cape Fold Ecoregion

The partitioning of limited resources commonly explains how different species can coexist within the same ecological community. In this 2010 study, the diets of three coexisting freshwater fishes (Cape galaxias Galaxias zebratus, n = 27; Cape kurper Sandelia capensis, n = 60; Breede River redfin Pseudobarbus burchelli, n = 77) were characterised and compared in three headwater streams in South Africa's Cape Fold Ecoregion using gut contents and stable isotope analyses. These data were analysed to ascertain whether the three species exploit distinct trophic niches. Both approaches provided evidence that these species occupy different trophic niches, though with some overlap. However, dietary differences among sites were not consistent and were probably influenced by site-specific factors like resource availability. Pseudobarbus burchelli had a broader niche breadth at Tierkloof Stream than the other two species, but not at Waaihoek or Tierstel Streams. Our results also suggest that P. burchelli consumed a more omnivorous diet than do the other two species, whereas S. capensis occupied a higher trophic position than the other two species and consumed vertebrates. Our findings suggest that these species occupy non-equivalent feeding niches in Cape Fold Ecoregion headwater streams, and that diet partitioning might facilitate their coexistence in these systems.     

Flux Analysis of Glucose Metabolism in Rhizopus oryzae for the Purpose of Increasing Lactate Yields

A flux analysis of glucose metabolism in the filamentous fungus Rhizopus oryzae was achieved using a specific radioactivity curve-matching program, TFLUX. Glycolytic and tricarboxylic acid cycle intermediates labeled through the addition of extracellular [U-14C]glucose were isolated and purified for specific radioactivity determinations. This information, together with pool sizes and the rates of glucose utilization and end product production, provided input for flux maps of the metabolic network under two different experimental conditions. Based upon the flux analysis of this system, a mutant of R. oryzae with higher lactate and lower ethanol yields than the parent was sought for and found.     

Increased activation of blood neutrophils after cigarette smoking in young individuals susceptible to COPD

Background

Cigarette smoking is the most important risk factor for Chronic Obstructive Pulmonary Disease (COPD). Only a subgroup of smokers develops COPD and it is unclear why these individuals are more susceptible to the detrimental effects of cigarette smoking. The risk to develop COPD is known to be higher in individuals with familial aggregation of COPD. This study aimed to investigate if acute systemic and local immune responses to cigarette smoke differentiate between individuals susceptible or non-susceptible to develop COPD, both at young (18-40 years) and old (40-75 years) age.

Methods

All participants smoked three cigarettes in one hour. Changes in inflammatory markers in peripheral blood (at 0 and 3 hours) and in bronchial biopsies (at 0 and 24 hours) were investigated. Acute effects of smoking were analyzed within and between susceptible and non-susceptible individuals, and by multiple regression analysis.

Results

Young susceptible individuals showed significantly higher increases in the expression of FcγRII (CD32) in its active forms (A17 and A27) on neutrophils after smoking (p = 0.016 and 0.028 respectively), independently of age, smoking status and expression of the respective markers at baseline. Smoking had no significant effect on mediators in blood or inflammatory cell counts in bronchial biopsies. In the old group, acute effects of smoking were comparable between healthy controls and COPD patients.

Conclusions

We show for the first time that COPD susceptibility at young age associates with an increased systemic innate immune response to cigarette smoking. This suggests a role of systemic inflammation in the early induction phase of COPD.

Trial registration

Clinicaltrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT00807469","term_id":"NCT00807469"}}NCT00807469

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0121-2) contains supplementary material, which is available to authorized users.     

Species distribution and <Emphasis Type="Italic">in vitro</Emphasis> antifungal susceptibility of oral yeast isolates from Tanzanian HIV-infected patients with primary and recurrent oropharyngeal candidiasis

Background  

In Tanzania, little is known on the species distribution and antifungal susceptibility profiles of yeast isolates from HIV-infected patients with primary and recurrent oropharyngeal candidiasis.