Evolution of gene families involved in banana fruit development and ripening : W077

A reference genome sequence of banana was recently obtained from a Musa acuminata doubled-haploid accession (DH-Pahang, 523 Mb) and organized into eleven pseudomolecules. This genome opens brand new perspectives for the identification of genes underlying key physiological processes and agricultural traits in this economically important species. To identify genes involved in banana fruit development and ripening, we used a whole genome-scale approach combining phylogenomic analyses and gene expression profiling. Global analysis of gene expression in banana fruits in response to ethylenic treatment was performed using RNA-seq. In parallel, gene families involved in core ethylene biosynthesis/signaling pathways and starch/sucrose metabolism were identified in the Musa genome using comparative genomics and phylogenomic analyses with eleven plant species. Our results showed a progressive global reprogramming of banana fruits during ripening characterized by an inhibition of the downstream ethylene signaling pathway. In addition, we identified expansions of gene families encoding transcriptional regulation elements of the ethylene signaling pathway in Musa. These expansions are currently analyzed in relation to Musa whole genome duplications. Finally, the combined structural and gene expression analyses led to the identification of candidate genes and gene family members involved in banana fruit ripening. (Résumé d'auteur

Hong-Ou-Mandel interference between independent III-V on silicon waveguide integrated lasers

The versatility of silicon photonic integrated circuits has led to a widespread usage of this platform for quantum information based applications, including Quantum Key Distribution (QKD). However, the integration of simple high repetition rate photon sources is yet to be achieved. The use of weak-coherent pulses (WCPs) could represent a viable solution. For example, Measurement Device Independent QKD (MDI-QKD) envisions the use of WCPs to distill a secret key immune to detector side channel attacks at large distances. Thus, the integration of III-V lasers on silicon waveguides is an interesting prospect for quantum photonics. Here, we report the experimental observation of Hong-Ou-Mandel interference with 46\pm 2% visibility between WCPs generated by two independent III-V on silicon waveguide integrated lasers. This quantum interference effect is at the heart of many applications, including MDI-QKD. Our work represents a substantial first step towards an implementation of MDI-QKD fully integrated in silicon, and could be beneficial for other applications such as standard QKD and novel quantum communication protocols.Comment: 5 pages, 3 figure

Traditional banana diversity in Oceania: an endangered heritage

This study aims to understand the genetic diversity of traditional Oceanian starchy bananas in order to propose an efficient conservation strategy for these endangered varieties. SSR and DArT molecular markers are used to characterize a large sample of Pacific accessions, from New Guinea to Tahiti and Hawaii. All Pacific starchy bananas are shown of New Guinea origin, by interspecific hybridization between Musa acuminata (AA genome), more precisely its local subspecies M. acuminata ssp. banksii, and M. balbisiana (BB genome) generating triploid AAB Pacific starchy bananas. These AAB genotypes do not form a subgroup sensu stricto and genetic markers differentiate two subgroups across the three morphotypes usually identified: Iholena versus Popoulu and Maoli. The Popoulu/Maoli accessions, even if morphologically diverse throughout the Pacific, cluster in the same genetic subgroup. However, the subgroup is not strictly monophyletic and several close, but different genotypes are linked to the dominant genotype. One of the related genotypes is specific to New Caledonia (NC), with morphotypes close to Maoli, but with some primitive characters. It is concluded that the diffusion of Pacific starchy AAB bananas results from a series of introductions of triploids originating in New Guinea area from several sexual recombination events implying different genotypes of M. acuminata ssp. banksii. This scheme of multiple waves from the New Guinea zone is consistent with the archaeological data for peopling of the Pacific. The present geographic distribution suggests that a greater diversity must have existed in the past. Its erosion finds parallels with the erosion of cultural traditions, inexorably declining in most of the Polynesian or Melanesian Islands. Symmetrically, diversity hot spots appear linked to the local persistence of traditions: Maoli in New Caledonian Kanak traditions or Iholena in a few Polynesian islands. These results will contribute to optimizing the conservation strategy for the ex-situ Pacific Banana Collection supported collectively by the Pacific countries

A chromosome 21-specific cosmid cocktail for the detection of chromosome 21 aberrations in interphase nuclei

Fluorescent in situ hybridization (FISH) with a 21q11-specific probe (CB21c1) consisting of three non-overlapping cosmids has been applied to interphase amniocytes of pregnancies at increased risk for fetal aneuploidy (N = 78) and to interphase lymphocytes, cultured and uncultured, of patients referred for Down syndrome (N = 19 and 28, respectively). In the uncultured amniocytes, six chromosome aberrations were detected: three cases of trisomy 21, a triploidy, a de novo 46,XX,t(21q21q), and a mosaic 46,XY/47,XY,+dic(21)(q11)/48,XY,+dic(21)(q11), +del(21)(q11). In 15 cultured and 20 uncultured blood samples, FISH correctly diagnosed trisomy 21 (full or mosaic) at the interphase level, which was confirmed in all cases by subsequent karyotyping. Because of specific and strong signals in interphase nuclei, CB21c1 appears to be a useful tool for the rapid detection of chromosome 21 abnormalities

False negative NIPT results: Risk figures for chromosomes 13,18 and 21 based on chorionic villi results in 5967 cases and literature review

Non-invasive prenatal testing (NIPT) demonstrated a small chance for a false negative result. Since the "fetal" DNA in maternal blood originates from the cytotrophoblast of chorionic villi (CV), some false negative results will have a biological origin. Based on our experience with cytogenetic studies of CV, we tried to estimate this risk. 5967 CV samples of pregnancies at high risk for common aneuplodies were cytogenetically investigated in our centre between January 2000 and December 2011. All cases of fetal trisomy 13,18 and 21 were retrospectively studied for the presence of a normal karyotype or mosaicism < 30% in short-term cultured (STC-) villi. 404 cases of trisomies 13,18 and 21 were found amongst 5967 samples (6,8%). Of these 404 cases, 14 (3,7%) had a normal or low mosaic karyotype in STC-villi and therefore would potentially be missed with NIPT. It involved 2% (5/242) of all trisomy 21 cases and 7.3% (9/123) of all trisomy 18 cases. In 1:426 (14/5967) NIPT samples of patients at high risk for common aneuploidies, a trisomy 18 or 21 will potentially be missed due to the biological phenomenon of absence of the chromosome aberration in the cytotrophoblast

Evaluation of a novel transition support intervention in an adult eating disorders service: ECHOMANTRA

Admissions and re-admissions for inpatient care for anorexia nervosa have been increasing. The aim of this study was to examine whether the transition from inpatient care to the community could be facilitated by supplementing usual treatment with ECHOMANTRA (transition interventions) for both patients and carers. A case series study was employed using a mixed-methods approach to measure the feasibility and efficacy of augmenting intensive hospital treatment with ECHOMANTRA. A consecutive series of consenting patients (n = 31) and carers (n = 21) were assessed on admission, discharge, and at 3 months follow-up. These outcomes were compared with audit data (n = 152) previously collected (2007–2017). The length of stay for the ECHOMANTRA intervention group was 4.5 weeks less than the comparison group, and weight gain was 0.11 kg per week higher. Improvements in patient symptomology were sustained at follow-up. Thematic analysis of the feedback from both patients and carers suggests that the intervention is valued. Carer burden was reduced and their skills improved (both moderate size changes). In conclusion, both the acceptability and efficiency of inpatient care for anorexia nervosa may be improved by augmenting treatment to prepare for transition from inpatient care by giving support to both patients and their carers