Quantification and characterisation of IgG binding to mould spores by flow cytometry and scanning electron microscopy

Characterization and pro-inflammatory potential of indoor mold particles

A number of epidemiological studies find an association between indoor air dampness and respiratory health effects. This is often suggested to be linked to enhanced mold growth. However, the role of mold is obviously difficult to disentangle from other dampness-related exposure including microbes as well as non-biological particles and chemical pollutants. The association may partly be due to visible mycelial growth and a characteristic musty smell of mold. Thus, the potential role of mold exposure should be further explored by evaluating information from experimental studies elucidating possible mechanistic links. Such studies show that exposure to spores and hyphal fragments may act as allergens and pro-inflammatory mediators and that they may damage airways by the production of toxins, enzymes, and volatile organic compounds. In the present review, we hypothesize that continuous exposure to mold particles may result in chronic low-grade pro-inflammatory responses contributing to respiratory diseases. We summarize some of the main methods for detection and characterization of fungal aerosols and highlight in vitro research elucidating how molds may induce toxicity and pro-inflammatory reactions in human cell models relevant for airway exposure. Data suggest that the fraction of fungal hyphal fragments in indoor air is much higher than that of airborne spores, and the hyphal fragments often have a higher pro-inflammatory potential. Thus, hyphal fragments of prevalent mold species with strong pro-inflammatory potential may be particularly relevant candidates for respiratory diseases associated with damp/mold-contaminated indoor air. Future studies linking of indoor air dampness with health effects should assess the toxicity and pro-inflammatory potential of indoor air particulate matter and combined this information with a better characterization of biological components including hyphal fragments from both pathogenic and non-pathogenic mold species. Such studies may increase our understanding of the potential role of mold exposure.

GlnR positive transcriptional regulation of the phosphate-specific transport system pstSCAB in Amycolatopsis mediterranei U32

Amycolatopsis mediterranei U32 is an important industrial strain for the production of rifamycin SV. Rifampicin, a derivative of rifamycin SV, is commonly used to treat mycobacterial infections. Although phosphate has long been known to affect rifamycin biosynthesis, phosphate transport, metabolism, and regulation are poorly understood in A. mediterranei. In this study, the functional phosphate transport system pstSCAB was isolated by RNA sequencing and inactivated by insertion mutation in A. mediterranei U32. The mycelium morphology changed from a filamentous shape in the wild-type and pstS1+ strains to irregular swollen shape at the end of filamentous in the ΔpstS1 strain. RT-PCR assay revealed that pstSCAB genes are co-transcribed as a polycistronic messenger. The pstSCAB transcription was significantly activated by nitrate supplementation and positively regulated by GlnR which is a global regulator of nitrogen metabolism in actinomycetes. At the same time, the yield of rifamycin SV decreased after mutation (ΔpstS1) compared with wild-type U32, which indicated a strong connection among phosphate metabolism, nitrogen metabolism, and rifamycin production in actinomycetes.

Blood or spores? A cautionary note on interpreting cellular debris on human skeletal remains

The identification of red blood cells on both skeletal human remains and decomposed corpses is of remarkable importance in forensic sciences, irrespective of its diagnostic value; their presence is often perplexing and difficult to interpret especially when in the context of decomposition and taphonomical variables. Some clinical research has focused on the morphological changes of red blood cells over time by scanning electron microscopy (SEM), but no research has investigated whether botanical structures can be confused for red blood cells. Since some literature has recently presumed the detection of erythrocyte-like cells on skeletal remains (even ancient) as surely erythrocytes, and most have never taken into consideration the chance of an origin different from blood, such as botanical, the present study aims at verifying the possibility of confusion between erythrocytes and botanical cells by applying SEM analysis and at highlighting the pitfalls in this particular issue through a test submitted to pathologists and natural scientists asked to discriminate between red blood cells and different vegetal structures (60 images obtained by SEM analysis). The results showed that although there are diagnostic features useful in identifying red blood cells from botanical structures, some spores resulted very similar to decaying red blood cells, which calls for attention and great caution when studying decomposed human remains.

Comparison of dry- and wet-based fine bead homogenizations to extract DNA from fungal spores

The present study explored DNA extraction kinetics from fungal spores, i.e., Aspergillus niger, Penicillium chrysogenum and Cladosporium sphaerospermum, by fine bead mill homogenization. In particular, the study aimed to investigate basic differences between the dry- and wet-based methods. The results showed higher initial rates of the DNA extractions by the dry-based method than by the wet-based method, due to higher collision efficiency among fine beads and fungal spores. Based on the experimental results, we constructed kinetic models. While the results by the wet-based method were fitted well with an existing first-order release-degradation model, the results by the dry-based method were not fitted well. Meanwhile, a newly constructed first-order release-degradation model, assuming a proportion of the DNA remained inside the disrupted spore cells and protected from further sheer stress, showed good correlations. The real-time PCR assays showed the PCR efficiencies of the DNA obtained by the dry-based method were higher than those by the wet-based method likely due to increased moderate fragmentation of the DNA by the dry-based method. Thus, although wet-based methods have been commonly used, dry-based methods might also be applicable to achieve efficient extraction and PCR amplification of fungal DNA.

Mould-specific immunoglobulin antibodies quantified by flow cytometry reflect mould exposure in Norwegian children

BACKGROUND

Studies from many countries have shown an association between dampness in buildings and airway symptoms. Little is known about the role of mould-specific IgG antibodies in this context. Objective To examine the IgG antibody response to mould applying a new flow cytometric assay, compare the results with the standardized ImmunoCap method, and evaluate the association of IgG to IgE antibodies, dampness in buildings, and airway symptoms like wheeze and asthma.

METHODS

A population of 3713 children 9-11 years of age living in Northern Norway was investigated for airway symptoms and dampness at homes by a parental questionnaire, using protocols of the International study of Asthma and Allergy in Childhood (ISAAC). Among these, a case-control study of 100 wheezers and 100 non-wheezers was established that included home inspection, a parental structured interview, and serum samples analysed for mould-specific IgG and IgE antibodies, total IgE, and specific IgE to an allergen panel (Phadiatop).

RESULTS

Self-reported visible signs of mould or moisture at home during the child's first year of life were a significant risk factor for both wheeze and asthma. The levels of mould-specific IgG antibodies were associated with mould and moisture findings, but only when IgG antibodies were measured by flow cytometry.

CONCLUSIONS

The results support that dampness at home can increase the risk of airway symptoms. IgG antibodies determined by flow cytometry reflect mould exposure better than antibodies measured by the conventional method. IgG antibodies measured by flow cytometry may be used as an indicator of mould exposure.