Éditeur(s) : HAL CCSD American Society for Microbiology
Résumé : International audience
This study aimed to evaluate the repeated sequence REP-529 compared to the B1 gene for the molecular diagnosis of toxoplasmosis by quantitative PCR (qPCR) in routine diagnosis.Over a ten-year period (2003-2013), all patients prospectively diagnosed with a positive REP-529 qPCR result for toxoplasmosis were included. All DNA samples (76 samples from 56 patients) were simultaneously tested using the two qPCR methods (REP-529 and B1).The mean Ct obtained with the B1 qPCR was significantly higher (+4.71 cycles) than that obtained with REP-529 qPCR (p<0.0001). Thirty-one out of 69 extracts (45.6%) positive with REP-529 qPCR were not amplified with the B1 qPCR (relative sensitivity 54.4%, compared to REP-529), yielding false negative results on 15/28 placentas, 5 cord blood, 2 amniotic fluids, 4 cerebrospinal fluids, 1 aqueous humor, 2 lymph node punctures and 1 abortion product. This defect in sensitivity would have left 20/56 patients undiagnosed, distributed as follows: 12/40 congenital toxoplasmosis, 4/5 cerebral toxoplasmosis, 2/8 patients with retinochoroiditis, and both patients with chronic lymphadenopathy. This poor performance of B1 qPCR could be related to low parasite loads, since the mean Toxoplasma quantification in extracts with B1 false negative results was 0.4 parasite/reaction.These results clearly show the superiority of the REP-529 sequence in the diagnosis of toxoplasmosis by PCR suggest that this target should be adopted as part of standardization of the PCR assay.
ISSN: 0095-1137

hal-01118293
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118293
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118293/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118293/file/A%2010-Year%20Retrospective%20Comparison%20of%20Two%20Target%20Sequences-belaz2015.pdf
PUBMEDCENTRAL : PMC4365238

Éditeur(s) : HAL CCSD
Résumé : International audience
Early antifungal therapeutic strategies are proposed during invasive fungal infection (IFI), but antifungal stewardship programs should institute a systematic reevaluation of prescriptions, particularly in the context of empirical treatment. Here, we aimed to evaluate the performances and particularly the negative predictive value (NPV) of diagnostic strategies, including a whole blood panfungal quantitative PCR assay (PF-qPCR) in a high risk population for IFI. The first step was to standardize and optimize a new PF- rtPCR targeting ITS2 region. Then, this method was evaluated in a multicenter prospective study including 313 patients with suspected IFI for whom an early antifungal treatment was prescribed. All patients enrolled at day 0 of their treatment benefited from serum Aspergillus galactomannan (GM) antigen detection twice a week, weekly PF-qPCR assay, and when indicated and feasible, CT-scan and mycological sampling. In total, 125 of 313 patients were diagnosed with IFI: 68 invasive aspergillosis (eight proven, 48 probable and 12 possible), one fusariosis, 47 candidemia, three disseminated candidiasis and six cryptococcosis. Globally, the sensitivity of the PF-qPCR assay was only 40%, but the specificity, PPV and NPV were 96%, 88% and 69%, respectively. In the population of patients at high risk for invasive aspergillosis who also benefited from Aspergillus GM detection, the sensitivity and the NPV of the combined detection reached to 78% and 84%, respectively. Even higher NPV were obtained when combining negative PF-qPCR and CT scan (95%) as well as negative GM and CT scan (93%), thus allowing to rationalize and re-evaluate the prescription of empirical treatment in such highly selected population.
The Journal of Infection

hal-01146845
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01146845
DOI : 10.1016/j.jinf.2015.04.005
PUBMED : 25896093

Éditeur(s) : HAL CCSD American Society for Microbiology
Résumé : International audience
Pneumocystis jirovecii pneumonia (PCP) is a life-threatening infection in immunocompromised patients. Quantitative real-time PCR (qPCR) is more sensitive than microscopic examination for the detection of P. jirovecii but also detects colonized patients. Hence, its positive predictive value (PPV) needs evaluation. In this 4-year prospective observational study, all immunocompromised patients with acute respiratory symptoms who were investigated for PCP were included, totaling 659 patients (814 bronchoalveolar lavage fluid samples). Patients with negative microscopy but positive qPCR were classified through medical chart review as having retained PCP, possible PCP, or colonization, and their clinical outcomes were compared to those of patients with microscopically proven PCP. Overall, 119 patients were included for analysis, of whom 35, 41, and 43 were classified as having retained PCP, possible PCP, and colonization, respectively. The 35 patients with retained PCP had clinical findings similar to those with microscopically proven PCP but lower fungal loads (P extless 0.001) and were mainly non-HIV-infected patients (P extless 0.05). Although the mean amplification threshold was higher in colonized patients, it was not possible to determine a discriminant qPCR cutoff. The PPV of qPCR in patients with negative microscopy were 29.4% and 63.8% when considering retained PCP and retained plus possible PCP, respectively. Patients with possible PCP had a higher mortality rate than patients with retained PCP or colonization (63% versus 3% and 16%, respectively); patients who died had not received co-trimoxazole. In conclusion, qPCR is a useful tool to diagnose PCP in non-HIV patients, and treatment might be better targeted through a multicomponent algorithm including both clinical/radiological parameters and qPCR results.
ISSN: 0095-1137

hal-01063906
https://hal.archives-ouvertes.fr/hal-01063906
DOI : 10.1128/JCM.01480-14
PUBMED : 25009050

Éditeur(s) : HAL CCSD
Résumé : International audience
Objective Macrophages may play a significant role in the initiating stages leading to chronic inflammation/infection in cystic fibrosis (CF), via an inability to act as a suppressor cell. In a previous study demonstrating impaired function of CF macrophage, we have shown high production of soluble CD14 (sCD14). The aim of the present work is to determine origin and function of sCD14 in blood monocyte-derived macrophages from stable adult CF patients. Methods To study origin, sCD14 is measured by ELISA in supernatant of macrophages from healthy subjects (non-CF) treated with PI-PLC or cholesterol. The involvement of sCD14 in inflammation, was investigated by analysis of NF-kB and caspase 1 pathways in non-CF macrophages treated by sCD14. Measurement of gene expression was done by qPCR and proteins were quantified by ELISA and Western blot. Results Treatment with PI-PLC increased sCD14 level in the supernatant of non-CF macrophages whereas cholesterol did not modified it. Furthermore high secretion of sCD14 from CF macrophages was decreased by an inhibitor of PI-PLC. Treatment with sCD14 increased pro-IL-1β, IL-8 and TNF-α expression resulting from NF-kB activation through IkBa phosphorylation, this effect was inhibited by NF-kB inhibitors. Also, activation of caspase 1 by cleavage of pro-caspase 1 allowed the secretion of mature IL-1β, inhibited by an inhibitor of caspase 1. However, inflammasome complex involved in caspase 1 activation remains to be determined. Conclusion This data show that origin of sCD14 is partly due to the action of lipases cutting the GPI tail that serves as a membrane anchor to CD14. Furthermore sCD14 have a role in chronic inflammation in CF
the 38th European Cystic Fibrosis Conference
Vienne, Austria

hal-01162773
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01162773
DOI : 10.1016/S1569-1993(15)30203-4

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Our goal was to determine if the US Environmental Relative Moldiness Index (ERMI) scale might have application in France. Twenty homes in Brittany, north western region of France were classified by inspection as "Moldy" or "Non-Moldy". Dust and air samples were collected (MiTest sampler or Coriolis sampler, respectively) from each home and analyzed by quantitative polymerase chain reaction (QPCR) for the 36 fungi that make-up the ERMI. Inspection and ERMI values provided a consistent assessment for 90% of the homes. Two homes originally classified as "Non-Moldy" were found to fit better into the "Moldy" category based on the QPCR analysis and the ERMI. Dust and air samples analyzed by QPCR provided similar fungal contamination assessments. In conclusion, a metric like the ERMI describes mold burdens in homes on a continuum, as opposed to the frequently used dichotomous approach (moldy vs. non-moldy). Although a larger, random national sampling of French homes is needed, these results suggest that these same 36 fungi may be useful in creating an ERMI for France.
ISSN: 1438-4639

inserm-00817898
http://www.hal.inserm.fr/inserm-00817898
http://www.hal.inserm.fr/inserm-00817898/document
http://www.hal.inserm.fr/inserm-00817898/file/Gangneux-Possible-Application-accepted.pdf
DOI : 10.1016/j.ijheh.2012.06.004

Éditeur(s) : HAL CCSD Frontiers Media
Résumé : "Candidatus Liberibacter solanacearum" (Lso) has emerged as a serious threat world-wide. Five Lso haplotypes have been identified so far. Haplotypes A and B are present in the Americas and/or New Zealand, where they are vectored to solanaceous plants by the potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae). The fastidious nature of these pathogens has hindered the study of the interactions with their eukaryotic hosts (vector and plant). To understand the strategies used by these pathogens to infect their vector, the effects of each Lso haplotype (A or B) on psyllid fitness was investigated, and genome-wide transcriptomic and RT-qPCR analyses were performed to evaluate Lso gene expression in association with its vector. Results showed that psyllids infected with haplotype B had significantly lower percentage of nymphal survival compared to psyllids infected with haplotype A. Although overall gene expression across Lso genome was similar between the two Lso haplotypes, differences in the expression of key candidate genes were found. Among the 16 putative type IV effector genes tested, four of them were differentially expressed between Lso haplotypes, while no differences in gene expression were measured by qPCR or transcriptomic analysis for the rest of the genes. This study provides new information regarding the pathogenesis of Lso haplotypes in their insect vector.
ISSN: 2235-2988

hal-01512244
https://hal.archives-ouvertes.fr/hal-01512244
https://hal.archives-ouvertes.fr/hal-01512244/document
https://hal.archives-ouvertes.fr/hal-01512244/file/Yao%202016%20Frontiers%20in%20Cellular%20and%20Infection%20Microbiology_%7BD6ACF6EB-9794-4F27-AB84-9EF4099B6D78%7D.pdf
DOI : 10.3389/fcimb.2016.00062

Éditeur(s) : HAL CCSD PeerJ
Résumé : International audience
The adaptative bleaching hypothesis (ABH) states that, depending on the symbiotic flexibility of coral hosts (i.e., the ability of corals to ''switch'' or ''shuffle'' their algal symbionts), coral bleaching can lead to a change in the composition of their associated Symbiodinium community and, thus, contribute to the coral's overall survival. In order to determine the flexibility of corals, molecular tools are required to provide accurate species delineations and to detect low levels of coral-associated Symbiodinium. Here, we used highly sensitive quantitative (real-time) PCR (qPCR) technology to analyse five common coral species from Moorea (French Polynesia), previously screened using only traditional molecular methods, to assess the presence of low-abundance (background) Symbiodinium spp. Similar to other studies, each coral species exhibited a strong specificity to a particular clade, irrespective of the environment. In addition, however, each of the five species harboured at least one additional Symbiodinium clade, among clades A–D, at background levels. Unexpectedly, and for the first time in French Polynesia, clade B was detected as a coral symbiont. These results increase the number of known coral-Symbiodinium associations from corals found in French Polynesia, and likely indicate an underestimation of the ability of the corals in this region to associate with and/or ''shuffle'' different Symbiodinium clades. Altogether our data suggest that corals from French Polynesia may favor a trade-off between optimizing symbioses with a specific Symbiodinium clade(s), maintaining associations with particular background clades that may play a role in the ability of corals to respond to environmental change. How to cite this article Rouzé et al. (2017), An updated assessment of Symbiodinium spp. that associate with common scleractinian corals from Moorea (French Polynesia) reveals high diversity among background symbionts and a novel finding of clade B.
ISSN: 2167-8359

Droits : info:eu-repo/semantics/OpenAccess
hal-01430294
https://hal-sde.archives-ouvertes.fr/hal-01430294
https://hal-sde.archives-ouvertes.fr/hal-01430294/document
https://hal-sde.archives-ouvertes.fr/hal-01430294/file/Rouze-2017-PeerJ-Updated.pdf
DOI : 10.7717/peerj.2856

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Environmental Relative Moldiness Index (ERMI) is a DNA-based metric developed to describe the fungal contamination in US dwellings. Our goal was to determine if the ERMI values in dwellings in north western France were correlated with other measures of fungal contamination. Dust and air samples were obtained from 40 dwellings and analyzed by quantitative PCR and/or by culturing. These dwellings were also inspected and the amount of visible fungal growth estimated in m(2). The ERMI values in these dwellings ranged from -2.7 to 28.8 and the fungal contamination estimates ranged from 0 to 20 m(2). The 40 dwellings were divided into those with a low (<6) or high (>8) ERMI values (n=20 in each). The average ERMI value was 15.70 for the high ERMI compared to 2.68 for the low ERMI dwellings. ERMI values were correlated (significant Kendall's tau values) with concentrations of fungi in air samples analyzed by QPCR or culturing. ERMI values were also correlated (significant Kendall's tau values) with the visible estimates of fungal contamination. Older dwellings were more likely to have higher ERMI values. These results suggest that the ERMI dust sample, which is quick and easy to collect, may be useful in making decisions about reducing fungal exposures in homes.
ISSN: 0048-9697

hal-00874733
https://hal.archives-ouvertes.fr/hal-00874733
DOI : 10.1016/j.scitotenv.2012.08.085
PUBMED : 23022719

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: Environmental factors such as pesticides can cause phenotypic changes in various organisms, including mammals. We studied the effects of the widely used herbicide atrazine (ATZ) on meiosis, a key step of gametogenesis, in male mice. METHODS: Gene expression pattern was analysed by Gene-Chip array. Genome-wide mapping of H3K4me3 marks distribution was done by ChIP-sequencing of testis tissue using Illumina technologies. RT-qPCR was used to validate differentially expressed genes or differential peaks. RESULTS: We demonstrate that exposure to ATZ reduces testosterone levels and the number of spermatozoa in the epididymis and delays meiosis. Using Gene-Chip and ChIP-Seq analysis of H3K4me3 marks, we found that a broad range of cellular functions, including GTPase activity, mitochondrial function and steroid-hormone metabolism, are affected by ATZ. Furthermore, treated mice display enriched histone H3K4me3 marks in regions of strong recombination (double-strand break sites), within very large genes and reduced marks in the pseudoautosomal region of X chromosome. CONCLUSIONS: Our data demonstrate that atrazine exposure interferes with normal meiosis, which affects spermatozoa production
ISSN: 1471-2164

hal-01225493
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01225493
DOI : 10.1186/s12864-015-2095-y
PUBMED : 26518232

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Interleukin-33 (IL-33), a cytokine belonging to the IL-1 family, is crucially involved in inflammatory pathologies including liver injury and linked to various modes of cell death. However, a link between IL-33 and necroptosis or programmed necrosis in liver pathology remains elusive. We aimed to investigate the regulation of IL-33 during necroptosis-associated liver injury. The possible regulation of IL-33 during liver injury by receptor-interacting protein kinase 1 (RIPK1) and poly(ADP-ribose) polymerase 1 (PARP-1) was investigated in mice in vivo and in hepatic stellate cells in vitro. The liver immunohistopathology, flow cytometry, serum transaminase measurement, ELISA, and qPCR-based cytokine measurement were carried out. By using a chemical approach, we showed that pretreatment of mice with Necrostatin-1 (Nec-1) (inhibitor of RIPK1) and/or PJ34 (inhibitor of PARP-1) significantly protected mice against concanavalin A (ConA) liver injury (aspartate amino-transferase (AST)/alanine amino-transferase (ALT)) associated with down-regulated hepatocyte-specific IL-33 expression. In contrast, the expression level of most systemic cytokines (except for IL-6) or activation of liver immune cells was not altered by chemical inhibitors rather an increased infiltration of neutrophils in the liver. During polyinosine-polycytidylic acid (Poly(I:C))-induced acute hepatitis, liver injury and hepatocyte-specific IL-33 expression was also inhibited by PJ34 without any protective effect of PJ34 in CCl4-induced liver injury. Moreover, PJ34 down-regulated the protein expression of IL-33 in activated hepatic stellate cells by cocktail of cytokines or staurosporine in vitro. In conclusion, we evidenced that the Nec-1/PJ34 is a potent inhibitor of liver injury and Nec-1/PJ34 down-regulated hepatocyte-specific IL-33 expression in the liver in vivo or in hepatic stellate cells in vitro, suggesting IL-33 as a possible readout of necroptosis-involved liver pathologies. Necroptosis inhibitors can protect mice against liver injury induced by ConA or Poly(I:C). IL-33 expression in liver injury in vivo is inhibited by PJ34. IL-33 expression in hepatic stellate cells in vitro is inhibited by PJ34. Hepatocyte-specific IL-33 expression is down-regulated by Nec-1/PJ34 during hepatitis. IL-33 is a new marker of necroptosis-associated liver injuries.
ISSN: 0946-2716

hal-01134319
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134319
DOI : 10.1007/s00109-015-1270-6
PUBMED : 25747661

Éditeur(s) : HAL CCSD Frontiers
Résumé : International audience
Important set of studies have demonstrated the endocrine disrupting activity of Bisphenol A (BPA). The present work aimed at defining estrogenic-like activity of several BPA structural analogs, including BPS, BPF, BPAF, and BPAP, on 4- or 7-day post-fertilization (dpf) zebrafish larva as an in vivo model. We measured the induction level of the estrogen-sensitive marker cyp19a1b gene (Aromatase B), expressed in the brain, using three different in situ/in vivo strategies: (1) Quantification of cyp19a1b transcripts using RT-qPCR in wild type 7-dpf larva brains exposed to bisphenols; (2) Detection and distribution of cyp19a1b transcripts using in situ hybridization on 7-dpf brain sections (hypothalamus); and (3) Quantification of the cyp19a1b promoter activity in live cyp19a1b-GFP transgenic zebrafish (EASZY assay) at 4-dpf larval stage. These three different experimental approaches demonstrated that BPS, BPF, or BPAF exposure, similarly to BPA, significantly activates the expression of the estrogenic marker in the brain of developing zebrafish. In vitro experiments using both reporter gene assay in a glial cell context and competitive ligand binding assays strongly suggested that up-regulation of cyp19a1b is largely mediated by the zebrafish estrogen nuclear receptor alpha (zfERα). Importantly, and in contrast to other tested bisphenol A analogs, the bisphenol AP (BPAP) did not show estrogenic activity in our model
ISSN: 1662-4548

hal-01299976
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01299976
PUBMED : 27047331
DOI : 10.3389/fnins.2016.00112
PUBMEDCENTRAL : PMC4805609

Éditeur(s) : HAL CCSD Cambridge University Press (CUP)
Résumé : International audience
Leishmania parasites can escape the immune response by invading cell types lacking leishmanicidal mechanisms. Silent persistence of Leishmania parasites in the host organism is responsible for asymptomatic carriage and relapses after cured leishmaniasis. Here, we studied the interaction between Hepatic Stellate Cells (HSC) and Leishmania. An original model of human HSC in primary culture infected with L. donovani was developed. The presence of intracellular parasites was studied and quantified using optical and confocal microscopy. HSC characteristics were studied using microscopy, methylene blue assay, long-term cultures and qPCR. We showed for the first time that human HSC are permissive to L. donovani infection, with no modification of HSC survival, growth rate and proinflammatory and fibrogenic characteristics. Intracellular parasites did not replicate but HSC had no effect on their survival. Indeed, after a 40-day culture, infected HSC cultures transferred on NNN medium yielded new promastigotes that were able to proliferate and efficiently infect new cells. HSC are permissive to L. donovani, with neither parasite killing nor apparent cell damage. Thus, HSC could act as potent sanctuary cells for Leishmania in the liver, which could partially explain parasite reactivation after an asymptomatic carriage or a cured visceral leishmaniasis.
ISSN: 0031-1820

inserm-00825803
http://www.hal.inserm.fr/inserm-00825803
DOI : 10.1017/S0031182012001965
PUBMED : 23253952

Éditeur(s) : HAL CCSD American Society for Microbiology
Résumé : International audience
UNLABELLED: During visceral leishmaniasis, the control of hepatic parasite burden is mainly due to granuloma assembly in a microenvironment consisting of both Th1 and Th2 components. Using enzyme-linked immunosorbent assay (ELISA) dosages, quantitative PCR (qPCR), immunohistochemistry, and flow cytometry, we studied the role of interleukin-33 (IL-33), a recently described cytokine signaling through the ST2 receptor, during visceral leishmaniasis. We showed that a higher level of IL-33 was detected in the serum of patients with visceral leishmaniasis than in that from healthy donors and demonstrated the presence of IL-33(+) cells in a liver biopsy specimen from a patient. Similarly, in BALB/c mice experimentally infected with L. donovani, a higher level of IL-33 was detected in the serum, as well as the presence of IL-33(+) cells and ST2(+) cells in the mouse liver. In ST2(-/-) BALB/c mice, better control of the hepatic parasite burden and reduced hepatomegaly were observed. This was associated with strong induction of Th1 cytokines (gamma interferon [IFN-γ] and IL-12) compared to the level in wild-type (WT) mice and better recruitment of myeloid cells associated with strongly induced chemokines (CCL2 and CXCL2) and receptors (CCR2 and CXCR2). Conversely, BALB/c mice treated twice weekly with recombinant IL-33 showed a dramatically reduced induction of Th1 cytokines and delayed inhibition of monocyte and neutrophil recruitment in the liver, which was associated with reduced KC/CXCL1 and CXCR2 expression. Taken together, our results suggest that IL-33 could be a new deleterious regulator of the hepatic immune response against Leishmania donovani, via the repression of the Th1 response and myeloid cell recruitment. IMPORTANCE: Visceral leishmaniasis is a life-threatening systemic disease due to the Leishmania protozoa L. infantum and L. donovani and is ranked by the World Health Organization as the second most important protozoan parasitic disease after malaria for its grave morbidity, high mortality, and global distribution. Leishmania parasites subvert the host's immune response to propagate to target organs, including the spleen, the bone marrow, and the liver. Control of hepatic parasite burdens depends on a delicate and poorly understood Th1/Th2 immune balance. To better understand this complex immune response, new cytokines are interesting targets for research studies. IL-33 is a newly described cytokine usually associated with Th2 response and involved in different diseases, including infectious diseases and hepatitis. Our results suggest that IL-33 could be a new factor of susceptibility and a potential prognostic marker during visceral leishmaniasis.
ISSN: 2150-7511

inserm-00871493
http://www.hal.inserm.fr/inserm-00871493
http://www.hal.inserm.fr/inserm-00871493/document
http://www.hal.inserm.fr/inserm-00871493/file/mBio.00383-13.pdf
DOI : 10.1128/mBio.00383-13

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
One of the most important topics that occupy public health problems is the air quality. That is the reason why mechanical ventilation and air handling units (AHU) were imposed by the different governments in the collective or individual buildings. Many buildings create an artificial climate using heating, ventilation and airconditioning (HVAC) systems. Among the existing aerosols in the indoor air, we can distinguish the bioaerosol with biological nature such as bacteria, viruses, fungi. Respiratory viral infections are a major public health issue because they are usually highly infective. We spend about 90% of our time in closed environments such as homes, workplaces or transport. Some studies have shown that AHU contribute to the spread and transport of viral particles within buildings. The aim of this work is to study the characterization of viral bioaerosols in indoor environments and to understand the fate of mengovirus eukaryote RNA virus on glass fiber filter F7 used in AHU. In this study, a setup close to reality of AHU system was used. The mengovirus aerosolized was characterized and measured with the Electrical Low Pressure Impact (ELPI) and the Scanner Mobility Particle Size (SMPS) and detected with RT-qPCR. The results about quantification and the level of infectivity of mengovirus on the filter and in the biosampler showed that mengovirus can pass through the filter and remain infectious upstream and downstream the system. Regarding the virus effectiveness on the filter under a constant air flow, and mengovirus was remained infectious during 10 hours after aerosolization.
ISSN: 1867-0334

hal-01636427
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01636427
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01636427/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01636427/file/Fate%20of%20mengovirus%20on%20fiberglass%20filter_accepted.pdf
DOI : 10.1007/s12560-017-9310-8

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
Respiratory illnesses have been linked to children's exposures to water-damaged homes. Therefore, understanding the microbiome in water-damaged homes is critical to preventing these illnesses. Few studies have quantified bacterial contamination, especially specific species, in water-damaged homes. We collected air and dust samples in twenty-one low-mold homes and twenty-one high-mold homes. The concentrations of three bacteria/genera, Stenotrophomonas maltophilia, Streptomyces sp., and Mycobacterium sp., were measured in air and dust samples using quantitative PCR (QPCR). The concentrations of the bacteria measured in the air samples were not associated with any specific home characteristic based on multiple regression models. However, higher concentrations of S. maltophilia in the dust samples were associated with water damage, that is, with higher floor surface moisture and higher concentrations of moisture-related mold species. The concentrations of Streptomyces and Mycobacterium sp. had similar patterns and may be partially determined by human and animal occupants and outdoor sources of these bacteria.
Indoor Air

hal-00877905
https://hal.archives-ouvertes.fr/hal-00877905
DOI : 10.1111/ina.12035
PUBMED : 23397905

Éditeur(s) : HAL CCSD Wiley Open Access
Résumé : International audience
Coral disease outbreaks have increased over the last three decades, but their causal agents remain mostly unclear (e.g., bacteria, viruses, fungi, protists). This study details a 14-month-long survey of coral colonies in which observations of the development of disease was observed in nearly half of the sampled colonies. A bimonthly qPCR method was used to quantitatively and qualitatively evaluate Symbiodinium assemblages of tagged colonies, and to detect the presence of Vibrio spp. Firstly, our data showed that predisposition to disease development in general, and, more specifically, infection by Vibrio spp. in Acropora cytherea depended on which clades of Symbiodinium were harbored. In both cases, harboring clade D rather than A was beneficial to the coral host. Secondly, the detection of Vibrio spp. in only colonies that developed disease strongly suggests opportunistic traits of the bacteria. Finally, even if sporadic cases of switching and probably shuffling were observed, this long-term survey does not suggest specific-clade recruitment in response to stressors. Altogether, our results demonstrate that the fitness of the coral holobiont depends on its initial consortium of Symbiodinium, which is distinct among colonies, rather than a temporary adaptation achieved through acquiring different Symbiodinium clades.
ISSN: 2045-7758

hal-01346931
https://hal-uvsq.archives-ouvertes.fr/hal-01346931
https://hal-uvsq.archives-ouvertes.fr/hal-01346931/document
https://hal-uvsq.archives-ouvertes.fr/hal-01346931/file/2016%20Rouze%20EcolEvol.pdf
DOI : 10.1002/ece3.1895

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: Color polymorphism in the nacre of pteriomorphian bivalves is of great interest for the pearl culture industry. The nacreous layer of the Polynesian black-lipped pearl oyster Pinctada margaritifera exhibits a large array of color variation among individuals including reflections of blue, green, yellow and pink in all possible gradients. Although the heritability of nacre color variation patterns has been demonstrated by experimental crossing, little isknown about the genes involved in these patterns. In this study, we identify a set of genes differentially expressed among extreme color phenotypes of P. margaritifera using a suppressive and subtractive hybridization (SSH) method comparing black phenotypes with full and half albino individuals.Results: Out of the 358 and 346 expressed sequence tags (ESTs) obtained by conducting two SSH libraries respectively, the expression patterns of 37 genes were tested with a real-time quantitative PCR (RT-qPCR) approach by pooling five individuals of each phenotype. The expression of 11 genes was subsequently estimated for each individual in order to detect inter-individual variation. Our results suggest that the color of the nacre is partiallyunder the influence of genes involved in the biomineralization of the calcitic layer. A few genes involved in the formation of the aragonite tablets of the nacre layer and in the biosynthesis chain of melanin also showed differential expression patterns. Finally, high variability in gene expression levels were observed within the black phenotypes.Conclusions: Our results revealed that three main genetic processes were involved in color polymorphisms: the biomineralization of the nacreous and calcitic layers and the synthesis of pigments such as melanin, suggesting that color polymorphism takes place at different levels in the shell structure. The high variability of gene expression found within black phenotypes suggests that the present work should serve as a basis for future studies exploringmore thoroughly the expression patterns of candidate genes within black phenotypes with different dominant iridescent colors.
ISSN: 1471-2164

hal-01260141
https://hal.archives-ouvertes.fr/hal-01260141
https://hal.archives-ouvertes.fr/hal-01260141/document
https://hal.archives-ouvertes.fr/hal-01260141/file/Lemer-2015-BMCGenom-Identification.pdf
DOI : 10.1186/s12864-015-1776-x

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Among persisting questions on bone calcification, a major one is the link between protein expression and mineral deposition. A cell culture system is here proposed opening new integrative studies on biomineralization, improving our knowledge on the role played by non-collagenous proteins in bone. This experimental in vitro model consisted in human primary osteoblasts cultured for 60 days at the surface of a 3D collagen scaffold mimicking an osteoid matrix. Various techniques were used to analyze the results at the cellular and molecular level (adhesion and viability tests, histology and electron microscopy, RT-and qPCR) and to characterize the mineral phase (histological staining, EDX, ATG, SAED and RMN). On long term cultures human bone cells seeded on the osteoid-like matrix displayed a clear osteoblast phenotype as revealed by the osteoblast-like morphology, expression of specific protein such as alkaline phosphatase and expression of eight genes classically considered as osteoblast markers, including BGLAP, COL1A1, and BMP2. Von Kossa and alizarine red allowed us to identify divalent calcium ions at the surface of the matrix, EDX revealed the correct Ca/P ratio, and SAED showed the apatite crystal diffraction pattern. In addition RMN led to the conclusion that contaminant phases were absent and that the hydration state of the mineral was similar to fresh bone. A temporal correlation was established between quantified gene expression of DMP1 and IBSP, and the presence of hydroxyapatite, confirming the contribution of these proteins to the mineralization process. In parallel a difference was observed in the expression pattern of SPP1 and BGLAP, which questioned their attributed role in the literature. The present model opens new experimental possibilities to study spatio-temporal relations between bone cells, dense collagen scaffolds, NCPs and hydroxyapatite mineral deposition. It also emphasizes the importance of high collagen density environment in bone cell physiology.
ISSN: 1932-6203

hal-01142641
http://hal.upmc.fr/hal-01142641
http://hal.upmc.fr/hal-01142641/document
http://hal.upmc.fr/hal-01142641/file/Silvent_2013_Collagen.pdf
DOI : 10.1371/journal.pone.0057344

Éditeur(s) : HAL CCSD SAGE Publications (UK and US)
Résumé : International audience
Enamel and enameloid, the highly mineralized tooth-covering tissues in living vertebrates, are different in their matrix composition. Enamel, a unique product of ameloblasts, principally contains enamel matrix proteins (EMPs), while enameloid possesses collagen fibrils and probably receives contributions from both odontoblasts and ameloblasts. Here we focused on type I collagen (COL1A1) and amelogenin (AMEL) gene expression during enameloid and enamel formation throughout ontogeny in the caudate amphibian, Pleurodeles waltl. In this model, pre-metamorphic teeth possess enameloid and enamel, while post-metamorphic teeth possess enamel only. In first-generation teeth, qPCR and in situ hybridization (ISH) on sections revealed that ameloblasts weakly expressed AMEL during late-stage enameloid formation, while expression strongly increased during enamel deposition. Using ISH, we identified COL1A1 transcripts in ameloblasts and odontoblasts during enameloid formation. COL1A1 expression in ameloblasts gradually decreased and was no longer detected after metamorphosis. The transition from enameloid-rich to enamel-rich teeth could be related to a switch in ameloblast activity from COL1A1 to AMEL synthesis. P. waltl therefore appears to be an appropriate animal model for the study of the processes involved during enameloid-to-enamel transition, especially because similar events probably occurred in various lineages during vertebrate evolution.
ISSN: 0022-0345

hal-01545475
https://hal.archives-ouvertes.fr/hal-01545475
DOI : 10.1177/0022034514526236

Éditeur(s) : HAL CCSD Wiley Open Access
Résumé : International audience
Coral disease outbreaks have increased over the last three decades, but their causal agents remain mostly unclear (e.g., bacteria, viruses, fungi, protists). This study details a 14-month-long survey of coral colonies in which observations of the development of disease was observed in nearly half of the sampled colonies. A bimonthly qPCR method was used to quantitatively and qualitatively evaluate Symbiodinium assemblages of tagged colonies, and to detect the presence of Vibrio spp. Firstly, our data showed that predisposition to disease development in general, and, more specifically, infection by Vibrio spp. in Acropora cytherea depended on which clades of Symbiodinium were harbored. In both cases, harboring clade D rather than A was beneficial to the coral host. Secondly, the detection of Vibrio spp. in only colonies that developed disease strongly suggests opportunistic traits of the bacteria. Finally, even if sporadic cases of switching and probably shuffling were observed, this long-term survey does not suggest specific-clade recruitment in response to stressors. Altogether, our results demonstrate that the fitness of the coral holobiont depends on its initial consortium of Symbiodinium, which is distinct among colonies, rather than a temporary adaptation achieved through acquiring different Symbiodinium clades.
ISSN: 2045-7758

hal-01270779
https://hal-univ-perp.archives-ouvertes.fr/hal-01270779
https://hal-univ-perp.archives-ouvertes.fr/hal-01270779/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01270779/file/41080.pdf
DOI : 10.1002/ece3.1895