Aflatoxin genes and the aflatoxigenic potential of Koji moulds

Sixty-four Aspergillus isolates, 54 of which originated from food fermentations, and 18 Aspergillus reference strains were identified and screened for the presence of aflatoxin genes aflR and omt-1. Among the Koji moulds, not only A. oryzae but also A. flavus strains were found. Furthermore, 27% of A. oryzae and 93% of A. flavus strains lacked either aflR or both aflR- and omt-1. A selection of 29 strains was also checked for the presence of pksA and nor-1. This revealed large deletions in the aflatoxin gene cluster of some strains. The hybridisation patterns also suggested a polarity in the deletion events, originating in the vicinity of pksA and extending towards omt-1. Other strains exhibited BamHI restriction fragment length polymorphisms (RFLPs) for either aflR or for aflR and omt-1. All aflR and/or omt-1 deletion strains turned out to be unable to produce aflatoxin. The RFLP-carrying strains either produced only traces of aflatoxin or none at all. In 73% of the A. oryzae strains, no apparent deletions were detected with the aflR and omt-1 probes. Nevertheless, after incubation in aflatoxin-inducing media, no aflatoxin B1 production could be detected in those A. oryzae strains.     

Biogenic Iron Preserves Structures during Fossilization: A Hypothesis

It is hypothesized that iron from biological tissues, liberated during decay, may have played a role in inhibiting loss of anatomical information during fossilization of extinct organisms. Most tissues in the animal kingdom contain iron in different forms. A widely distributed iron-bearing molecule is ferritin, a globular protein that contains iron crystallites in the form of ferrihydrite minerals. Iron concentrations in ferritin are high and ferrihydrites are extremely reactive. When ancient animals are decaying on the sea floor under anoxic environmental conditions, ferrihydrites may initialize the selective replication of some tissues in pyrite FeS₂. This model explains why some labile tissues are preserved, while other more resistant structures decay and are absent in many fossils. A major implication of this hypothesis is that structures described as brains in Cambrian arthropods are not fossilization artifacts, but are instead a source of information on anatomical evolution at the dawn of complex animal life.     

The N-glycosylation defect of cwh8Delta yeast cells causes a distinct defect in sphingolipid biosynthesis

CWH8/YGR036c of Saccharomyces cerevisiae has been identifiedas a dolichylpyrophosphate (Dol-PP) phosphatase that removesa phosphate from the Dol-PP generated by the oligosaccharyltransferase(OST), while it adds N-glycans to nascent glycoproteins in theendoplasmic reticulum (ER). Lack of CWH8 was proposed to interruptthe so called dolichol (Dol) cycle by trapping Dol in the formof Dol-PP in the ER lumen. Indeed, cwh8D mutants display a severedeficiency in N-glycosylation. We find that cwh8D mutants havestrongly reduced levels of inositolphosphorylceramide (IPC),whereas its derivative, mannosyl-(inositol-P)₂-ceramide (M(IP)₂C)is not affected. Microsomes of cwh8D contain normal ceramidesynthase and IPC synthesis activities. Within a large panelof mutants affecting Dol dependent pathways such as N- or O-glycosylation,or glycosylphosphatidyl inositol (GPI)-anchoring, only the mutantshaving a deficiency of N-glycan addition show the defect inIPC biosynthesis. By mutating genes required for the additionof N-glycans or by treating cells with tunicamycin (Tm) onecan similarly reduce the steady state level of IPC and exactlyreproduce the phenotype of cwh8D cells. Some potential mechanismsby which the lack of N-glycans could lead to the sphingolipidabnormality were further explored.     

Dragon (repulsive guidance molecule b) inhibits IL-6 expression in macrophages

Despite the strong interest in the NK cell-mediated immunity toward malignant cells and viruses, there is a relative lack of data on the interplay between NK cells and filamentous fungi, especially Aspergillus fumigatus, which is the major cause of invasive aspergillosis. By studying the in vitro interaction between human NK cells and A. fumigatus, we found only germinated morphologies to be highly immunogenic, able to induce a Th1-like response, and capable of upregulating cytokines such as IFN-γ and TNF-α. Moreover, priming NK cells with human rIL-2 and stimulating NK cells by direct NK cell-pathogen contact were essential to induce damage against A. fumigatus. However, the most interesting finding was that NK cells did not mediate anti-Aspergillus cytotoxicity through degranulation of their cytotoxic proteins (perforin, granzymes, granulysine), but via an alternative mechanism involving soluble factor(s). To our knowledge, our study is the first to demonstrate that IFN-γ, released by NK cells, directly damages A. fumigatus, attributing new properties to both human NK cells and IFN-γ and suggesting them as possible therapeutic tools against IA.     

Catheter-related infections

Nosocomial infections are a leading cause of morbidity and mortality among hospitalized patients. These infections have made newspaper headlines recently in many countries, and both patients and their relatives are now perfectly aware of their existence and of the risks which are inherent to any medical activity. However, significant improvements in the knowledge of the pathophysiology and epidemiology of nosocomial infections allow us to prevent them efficiently. Accordingly, they should no longer be considered as an inevitable tribute to pay to the continuous progress of medicine, but as a real challenge in the process of improving the quality of patient care. This is particularly the case for bloodstream infections, of which at least 80% are considered to be catheter associated. This paper reviews the epidemiology and impact of infections associated with the use of intravenous catheters. Principles of therapy are reviewed, as well as major aspects of prevention.     

Efficacy of a New Educational Tool to Improve Handrubbing Technique amongst Healthcare Workers: A Controlled,Before-After Study

Introduction

Hand hygiene is a key component of infection control in healthcare. WHO recommends that healthcare workers perform six specific poses during each hand hygiene action. SureWash (Glanta Ltd, Dublin, Ireland) is a novel device that uses video-measurement technology and immediate feedback to teach this technique. We assessed the impact of self-directed SureWash use on healthcare worker hand hygiene technique and evaluated the device''s diagnostic capacity.

Methods

A controlled before-after study: subjects in Group A were exposed to the SureWash for four weeks followed by Group B for 12 weeks. Each subject''s hand hygiene technique was assessed by blinded observers at baseline (T₀) and following intervention periods (T₁ and T₂). Primary outcome was performance of a complete hand hygiene action, requiring all six poses during an action lasting ≥20 seconds. The number of poses per hand hygiene action (maximum 6) was assessed in a post-hoc analysis. SureWash''s diagnostic capacity compared to human observers was assessed using ROC curve analysis.

Results

Thirty-four and 29 healthcare workers were recruited to groups A and B, respectively. No participants performed a complete action at baseline. At T₁, one Group A participant and no Group B participants performed a complete action. At baseline, the median number of poses performed per action was 2.0 and 1.0 in Groups A and B, respectively (p = 0.12). At T₁, the number of poses per action was greater in Group A (post-intervention) than Group B (control): median 3.8 and 2.0, respectively (p<0.001). In Group A, the number of poses performed twelve weeks post-intervention (median 3.0) remained higher than baseline (p<0.001). The area under the ROC curves for the 6 poses ranged from 0.59 to 0.88.

Discussion

While no impact on complete actions was demonstrated, SureWash significantly increased the number of poses per hand hygiene action and demonstrated good diagnostic capacity.