Evidence for cutaneous dysbiosis in dystrophic epidermolysis bullosa.

BACKGROUND: The human microbiome project addresses the relationship between bacterial flora and the human host, in both healthy and diseased conditions. The skin is an ecosystem with multiple niches, each featuring unique physiological conditions and thus hosting different bacterial populations. The skin microbiome has been implicated in the pathogenesis of many dermatoses. Given the role of dysbiosis in the pathogenesis of inflammation, which is prominent in dystrophic epidermolysis bullosa (DEB), we undertook a study on the skin microbiome. AIM: To characterize the skin microbiome in a series of patients with DEB. METHODS: This was a case-control study of eight patients with DEB and nine control cases enrolled between June 2017 and November 2018. The skin of patients with DEB was sampled at three different sites: untreated wound, perilesional skin and normal-appearing (uninvolved) skin. Normal skin on the forearm was sampled from age-matched healthy controls (HCs). We used a dedicated DNA extraction protocol to isolate microbial DNA, which was then analysed using next-generation microbial 16S rRNA sequencing. Data were analysed using a series of advanced bioinformatics tools. RESULTS: The wounds, perilesional and uninvolved skin of patients with DEB demonstrated reduced bacterial diversity compared with HCs, with the flora in DEB wounds being the least diverse. We found an increased prevalence of staphylococci species in the lesional and perilesional skin of patients with DEB, compared with their uninvolved, intact skin. Similarly, the uninvolved skin of patients with DEB displayed increased staphylococcal content and significantly different microbiome diversities (other than staphylococci) compared with HC skin. CONCLUSIONS: These findings suggest the existence of a unique DEB-associated skin microbiome signature, which could be targeted by specific pathogen-directed therapies. Moreover, altering the skin microbiome with increasing colonization of bacteria associated with nonchronic wounds may potentially facilitate wound healing in patients with DEB.

A genetic map of melon highly enriched with fruit quality QTLs and EST markers, including sugar and carotenoid metabolism genes.

A genetic map of melon enriched for fruit traits was constructed, using a recombinant inbred (RI) population developed from a cross between representatives of the two subspecies of Cucumis melo L.: PI 414723 (subspecies agrestis) and 'Dulce' (subspecies melo). Phenotyping of 99 RI lines was conducted over three seasons in two locations in Israel and the US. The map includes 668 DNA markers (386 SSRs, 76 SNPs, six INDELs and 200 AFLPs), of which 160 were newly developed from fruit ESTs. These ESTs include candidate genes encoding for enzymes of sugar and carotenoid metabolic pathways that were cloned from melon cDNA or identified through mining of the International Cucurbit Genomics Initiative database (http://www.icugi.org/). The map covers 1,222 cM with an average of 2.672 cM between markers. In addition, a skeleton physical map was initiated and 29 melon BACs harboring fruit ESTs were localized to the 12 linkage groups of the map. Altogether, 44 fruit QTLs were identified: 25 confirming QTLs described using other populations and 19 newly described QTLs. The map includes QTLs for fruit sugar content, particularly sucrose, the major sugar affecting sweetness in melon fruit. Six QTLs interacting in an additive manner account for nearly all the difference in sugar content between the two genotypes. Three QTLs for fruit flesh color and carotenoid content were identified. Interestingly, no clear colocalization of QTLs for either sugar or carotenoid content was observed with over 40 genes encoding for enzymes involved in their metabolism. The RI population described here provides a useful resource for further genomics and metabolomics studies in melon, as well as useful markers for breeding for fruit quality.