New and old microbial communities colonizing a seventeenth-century wooden church.

The North of Romania is known for its wooden churches dating from the seventeenth and eighteenth centuries. Their deterioration constitutes a major problem due to their value for the cultural heritage. The microbial community from a seventeenth-century wooden church (Nicula, Romania) was investigated by characterization of uncultivated and cultivated bacteria using 16S rDNA sequence analysis. The study revealed not only the prevalence of the Bacillus thuringiensis strain IAM 12077 but also the presence of new microbial communities of Planomicrobium and Variovorax that were not previously reported in paintings or on wood. The identification of fungi showed the presence of seven common genera found on the walls and icon surfaces. Common bacteria from the human oral microbiota were not identified in the bacterial community.

In vitro evaluation of the effects of yttria-alumina-silica microspheres on human keratinocyte cells.

The behavior of yttria-alumina-silica spray-dried microspheres was investigated in vitro on a human keratinocyte cell line, first to exclude their cytotoxicity. The HaCaT cells were chosen due to their well-characterized phenotype and their phagocytic ability. Microscopic analysis and cell viability tests showed no negative effect of the microspheres on cells morphology and behavior. Scanning electron microscopy and transmission electron microscopy results evidenced the cellular internalization of the microspheres at 48 h after their incubation with cultured cells. The shape, size distribution, structure, composition, and chemical states of the elements on samples surface were analyzed by SEM, transmission electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy, because these properties could influence their internalization by cells. The yttrium distribution on the microspheres surface was indicated by fluorescence microscopy imaging. The microspheres dimension and shape inside the cells was in accordance with their dimension and shape before incubation. The microspheres seemed captured and engulfed by the cells in native form and appeared resistant to degradation over the first 48 h. Most of the analyzed cells took up more microspheres, suggesting that the microspheres were actively phagocytosed by the cells and accumulated within the cytoplasm. X-ray photoelectron spectroscopy results on Al and Si atomic environments denoted Al-O-Si crosslinks, which improve the surface protection to corrosion.

Binding of avian IgY to type VII collagen does not activate complement and leucocytes and fails to induce subepidermal blistering in mice.

BACKGROUND: Epidermolysis bullosa acquisita (EBA) is a severe autoimmune skin disease characterized by tissue-bound and circulating autoantibodies to type VII collagen, the major component of anchoring fibrils. When passively transferred into mice, rabbit IgG against type VII collagen induces Fc-dependent activation of complement, the recruitment of leucocytes into the skin, and subepidermal blistering. In addition to these inflammatory mechanisms, clinical and experimental evidence suggests that antibodies against type VII collagen might induce blisters by disrupting the ligand function of type VII collagen by an Fc-independent mechanism. OBJECTIVES: To study noninflammatory mechanisms of blister formation in experimental EBA. METHODS: We generated chicken IgY antibodies directed to recombinant type VII collagen and examined their pathogenic activity using ex vivo and animal models. RESULTS: Mice injected with these chicken IgY antibodies showed binding of the antibodies to the dermal-epidermal junction of skin sections. However, IgY antibodies did not fix complement C3 in enzyme-linked immunosorbent assay and immunofluorescence complement-binding assays. In addition, IgY antibodies did not induce dermal-epidermal separation ex vivo. Following their passive transfer into Balb/c mice, chicken IgY antibodies against type VII collagen bound at the dermal-epidermal junction, but, in contrast to rabbit IgG, did not fix complement C3, recruit granulocytes, or induce skin blisters. CONCLUSIONS: These findings demonstrate that binding of avian IgY to type VII collagen is not pathogenic in vivo and strongly suggest that in experimental EBA, antibodies to type VII collagen induce blisters not by direct disruption of the ligand function of type VII collagen, but rather by an Fc-dependent engagement of humoral and cellular inflammatory factors.

NADPH oxidase is required for neutrophil-dependent autoantibody-induced tissue damage.

The contribution of phagocyte-derived reactive oxygen species to tissue injury in autoimmune inflammatory diseases is unclear. Here we report that granulocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase crucially contributes to tissue injury in experimental models of the antibody-mediated autoimmune disease epidermolysis bullosa acquisita. Neutrophil cytosolic factor 1-deficient mice lacking functional NADPH oxidase were resistant to skin blistering by the passive transfer of antibodies against type VII collagen. Pharmacological inhibition or deficiency of human NADPH oxidase abolished dermal-epidermal separation caused by autoantibodies and granulocytes ex vivo. In addition, recruitment of granulocytes into the skin was required for tissue injury, as demonstrated by the resistance to experimental blistering of wild-type mice depleted of neutrophils and of CD18-deficient mice. Transfer of neutrophil cytosolic factor 1-sufficient granulocytes into neutrophil cytosolic factor 1-deficient mice demonstrated that granulocytes provide the NADPH oxidase required for tissue damage. Our findings identify granulocyte-derived NADPH oxidase as a key molecular effector engaged by pathogenic autoantibodies and provide relevant targets for prevention of tissue damage in granulocyte-mediated autoimmune diseases.