Identifying group-specific primers for environmental Heterolobosa by high-throughput sequencing.

Diversity of Heterolobosea (Excavata) in environments is poorly understood despite their ecological occurrence and health-associated risk, partly because this group tends to be under-covered by most universal eukaryotic primers used for sequencing. To overcome the limits of the traditional morpho-taxonomy-based biomonitoring, we constructed a primer database listing existing and newly designed specific primer pairs that have been evaluated for Heterolobosea 18S rRNA sequencing. In silico taxonomy performance against the current SILVA SSU database allowed the selection of primer pairs that were next evaluated on reference culture amoebal strains. Two primer pairs were retained for monitoring the diversity of Heterolobosea in freshwater environments, using high-throughput sequencing. Results showed that one of the newly designed primer pairs allowed species-level identification of most heterolobosean sequences. Such primer pair could enable informative, cultivation-free assays for characterizing heterolobosean populations in various environments.

Isolation and Characterization of Cat Olfactory Ecto-Mesenchymal Stem Cells.

The olfactory mucosa contains olfactory ecto-mesenchymal stem cells (OE-MSCs) which show stemness features, multipotency capabilities, and have a therapeutic potential. The OE-MSCs have already been collected and isolated from various mammals. The aim of this study was to evaluate the feasibility of collecting, purifying and amplifying OE-MSCs from the cat nasal cavity. Four cats were included in the study. Biopsies of olfactory mucosa were performed on anesthetized animals. Then, the olfactory OE-MSCs were isolated, and their stemness features as well as their mesodermal differentiation capabilities were characterized. Olfactory mucosa biopsies were successfully performed in all subjects. From these biopsies, cellular populations were rapidly generated, presenting various stemness features, such as a fibroblast-like morphology, nestin and MAP2 expression, and sphere and colony formation. These cells could differentiate into neural and mesodermal lineages. This report shows for the first time that the isolation of OE-MSCs from cat olfactory mucosa is possible. These cells showed stemness features and multilineage differentiation capabilities, indicating they may be a promising tool for autologous grafts and feline regenerative medicine.

Anti-biofilm activity of a semi-synthetic molecule obtained from resveratrol against Candida albicans biofilm.

Candida albicans can form biofilm on tissues and medical devices, becoming, in that case, less susceptible to antifungal agents. Treatment of candidiasis associated with the formation of C. albicans biofilms is restricted to echinocandins and lipid forms of amphotericin B. This study investigated the activity of micafungin and resveratrol modified molecule (EB487) against C. albicans biofilms. The anti-biofilm growth (Bgrowth) and anti-preformed biofilm (Bpreformed) activities of micafungin (0 to 3.94 µM) and EB487 (0 to 20.32 mM) were comparatively studied separately and combined, using XTT, flow cytometry and cell counts approaches. Concentrations causing 50% inhibition of the studied steps (IC50) were evaluated. When tested separately, IC50 Bgrowth was obtained for 4.8 mM and 0.13 µM of EB487 and micafungin respectively, and IC50 Bpreformed for 3.6 mM and 0.06 µM of EB487 and micafungin respectively. Micafungin used alone was not able to totally eradicate fungi. Micafungin combined with EB487 displayed synergistic activity (both anti-growth- and anti-preformed biofilm-activities). Optimal combination concentrations were EB487 (≤9.12 mM -strain ATCC 28367™ or ≤8.12 mM -strain CAI4-p), micafungin (≤0.05 µM for both) and caused a total eradication of fungi. Dose reduction indexes obtained using these concentrations were at least 9 (micafungin) and 3.2 (EB487) for both anti-biofilm growth- and anti-preformed biofilm-activities. Combinations indexes were consistently below one, demonstrating a synergistic relationship between micafungin and EB487 in these conditions. This study demonstrated the strong anti-biofilm activity of EB487 and highlighted its synergistic potential when combined with micafungin. EB487 is a promising semi-synthetic molecule with prophylactic and curative interests in fighting C. albicans biofilms.

Human germinal center transcriptional programs are de-synchronized in B cell lymphoma.

Most adult B cell lymphomas originate from germinal center (GC) B cells, but it is unclear to what extent B cells in overt lymphoma retain the functional dynamics of GC B cells or are blocked at a particular stage of the GC reaction. Here we used integrative single-cell analysis of phenotype, gene expression and variable-region sequence of the immunoglobulin heavy-chain locus to track the characteristic human GC B cell program in follicular lymphoma B cells. By modeling the cyclic continuum of GC B cell transitional states, we identified characteristic patterns of synchronously expressed gene clusters. GC-specific gene-expression synchrony was lost in single lymphoma B cells. However, distinct follicular lymphoma-specific cell states co-existed within single patient biopsies. Our data show that lymphoma B cells are not blocked in a GC B cell state but might adopt new dynamic modes of functional diversity, which opens the possibility of novel definitions of lymphoma identity.

Cutibacterium acnes protects Candida albicans from the effect of micafungin in biofilms.

The aim of this study was to investigate the ability of Candida albicans and Cutibacterium acnes to grow together as a polymicrobial biofilm in vitro and to examine the influence of C. acnes on C. albicans susceptibility to micafungin. Mature 72-h-old single-species biofilms of C. albicans and polymicrobial biofilms involving both C. albicans and C. acnes were formed in brain-heart infusion and were observed by scanning electronic microscopy. Moreover, 24-h-old single-species and polymicrobial biofilms were treated for 24 h with micafungin (concentrations ranging from 0.75 mg/L to 12 mg/L) and the antibiofilm activity of micafungin was evaluated on fungal cells by flow cytometry following addition of propidium iodide. The results showed that C. albicans and C. acnes formed a polymicrobial biofilm in the tested conditions and that bacterial presence did not modify fungal viability. Micafungin induced a fungal mortality rate ranging from 70-95% in C. albicans single-species biofilms and from 35-40% in C. acnes-C. albicans polymicrobial biofilms. Mortality induced by micafungin was significantly reduced (P < 0.05 for micafungin at 6 mg/L and P < 0.001 for other micafungin concentrations) in polymicrobial conditions compared with single-species biofilms. In conclusion, this study showed that C. albicans and C. acnes are able to form polymicrobial biofilms together in a synergistic way and that this organisation increases yeast resistance to micafungin.