Microarray transcriptional profiling of Arctic Mesorhizobium strain N33 at low temperature provides insights into cold adaption strategies

Background: Arctic Mesorhizobium strain N33 was isolated from nodules of the legume Oxytropis arctobia in Canada’s eastern Arctic. This symbiotic bacterium can grow at temperatures ranging from 0 to 30 °C, fix nitrogen at 10 °C, and is one of the best known cold-adapted rhizobia. Despite the economic potential of this bacterium for northern regions, the key molecular mechanisms of its cold adaptation remain poorly understood. Results: Using a microarray printed with 5760 Arctic Mesorhizobium genomic clones, we performed a partial transcriptome analysis of strain N33 grown under eight different temperature conditions, including both sustained and transient cold treatments, compared with cells grown at room temperature. Cells treated under constant (4 and 10 °C) low temperatures expressed a prominent number of induced genes distinct from cells treated to short-term cold-exposure (<60 min), but exhibited an intermediate expression profile when exposed to a prolonged cold exposure (240 min). The most prominent up-regulated genes encode proteins involved in metabolite transport, transcription regulation, protein turnover, oxidoreductase activity, cryoprotection (mannitol, polyamines), fatty acid metabolism, and membrane fluidity. The main categories of genes affected in N33 during cold treatment are sugar transport and protein translocation, lipid biosynthesis, and NADH oxidoreductase (quinone) activity. Some genes were significantly down-regulated and classified in secretion, energy production and conversion, amino acid transport, cell motility, cell envelope and outer membrane biogenesis functions. This might suggest growth cessation or reduction, which is an important strategy to adjust cellular function and save energy under cold stress conditions. Conclusion: Our analysis revealed a complex series of changes associated with cold exposure adaptation and constant growth at low temperatures. Moreover, it highlighted some of the strategies and different physiological states that Mesorhizobium strain N33 has developed to adapt to the cold environment of the Canadian high Arctic and has revealed candidate genes potentially involved in cold adaptati

Metabolomic analysis of cold acclimation of arctic mesorhizobium sp. strain N33

Arctic Mesorhizobium sp. N33 isolated from nodules of Oxytropis arctobia in Canada’s eastern Arctic has a growth temperature range from 0°C to 30°C and is a well-known cold-adapted rhizobia. The key molecular mechanisms underlying cold adaptation in Arctic rhizobia remains totally unknown. Since the concentration and contents of metabolites are closely related to stress adaptation, we applied GC-MS and NMR to identify and quantify fatty acids and water soluble compounds possibly related to low temperature acclimation in strain N33. Bacterial cells were grown at three different growing temperatures (4°C, 10°C and 21°C). Cells from 21°C were also cold-exposed to 4°C for different times (2, 4, 8, 60 and 240 minutes). We identified that poly-unsaturated linoleic acids 18∶2 (9, 12) & 18∶2 (6, 9) were more abundant in cells growing at 4 or 10°C, than in cells cultivated at 21°C. The mono-unsaturated phospho/neutral fatty acids myristoleic acid 14∶1(11) were the most significantly overexpressed (45-fold) after 1hour of exposure to 4°C. As reported in the literature, these fatty acids play important roles in cold adaptability by supplying cell membrane fluidity, and by providing energy to cells. Analysis of water-soluble compounds revealed that isobutyrate, sarcosine, threonine and valine were more accumulated during exposure to 4°C. These metabolites might play a role in conferring cold acclimation to strain N33 at 4°C, probably by acting as cryoprotectants. Isobutyrate was highly upregulated (19.4-fold) during growth at 4°C, thus suggesting that this compound is a precursor for the cold-regulated fatty acids modification to low temperature adaptation

Control of somatic embryogenesis and embryo development by AP2 transcription factors

Members of the AP2 family of transcription factors, such as BABY BOOM (BBM), play important roles in cell proliferation and embryogenesis in Arabidopsis thaliana (AtBBM) and Brassica napus (BnBBM) but how this occurs is not understood. We have isolated three AP2 genes (GmBBM1, GmAIL5, GmPLT2) from somatic embryo cultures of soybean, Glycine max (L.) Merr, and discovered GmBBM1 to be homologous to AtBBM and BnBBM. GmAIL5 and GmPLT2 were homologous to Arabidopsis AINTEGUMENTA-like5 (AIL5) and PLETHORA2 (PLT2), respectively. Constitutive expression of GmBBM1 in Arabidopsis induced somatic embryos on vegetative organs and other pleiotropic effects on post-germinative vegetative organ development. Sequence comparisons of BBM orthologues revealed the presence of ten sequence motifs outside of the AP2 DNA-binding domains. One of the motifs, bbm-1, was specific to the BBM-like genes. Deletion and domain swap analyses revealed that bbm-1 was important for somatic embryogenesis and acted cooperatively with at least one other motif, euANT2, in the regulation of somatic embryogenesis and embryo development in transgenic Arabidopsis. The results provide new insights into the mechanisms by which BBM governs embryogenesis

Getting ready for transition to adult care : tool validation and multi-informant strategy using the Transition Readiness Assessment Questionnaire in pediatrics

Background Transitioning from pediatric to adult healthcare can be challenging and lead to severe consequences if done suboptimally. The Transition Readiness Assessment Questionnaire (TRAQ) was developed to assess adolescent and young adult (AYA) patients' transition readiness. In this study, we aimed to (1) document the psychometric properties of the French-language version of the TRAQ (TRAQ-FR), (2) assess agreements and discrepancies between AYA patients' and their primary caregivers' TRAQ-FR scores, and (3) identify transition readiness contributors. Methods French-speaking AYA patients (n = 175) and primary caregivers (n = 168) were recruited from five clinics in a tertiary Canadian hospital and asked to complete the TRAQ-FR, the Pediatric Quality of Life Inventory™ 4.0 (PedsQL™ 4.0), and a sociodemographic questionnaire. The validity of the TRAQ-FR was assessed using confirmatory factor analyses (CFA). Agreements and discrepancies were evaluated using intraclass correlation coefficients and paired-sample t tests. Contributors of transition readiness were identified using regression analyses. Results The five-factor model of the TRAQ was supported, with the TRAQ-FR global scale showing good internal consistency for both AYA patients' and primary caregivers' scores (α = .85–.87). AYA patients and primary caregivers showed good absolute agreement on the TRAQ-FR global scale with AYA patients scoring higher than primary caregivers (ICC = .80; d = .25). AYA patients' age and sex were found to be contributors of transition readiness. Conclusions The TRAQ-FR was found to have good psychometric properties when completed by both AYA patients and primary caregivers. Additional research is needed to explore the predictive validity and clinical use of the TRAQ-FR

Vie quotidienne, culture télé et construction de l'identité familiale

Drawing on interviews with families in Québec on their mode of « recounting life », the authors analyse the place occupied by television in the social construction of the family identity. By the meanings they attribute to the media and to the messages which populate their domestic environment, members of the family cell become active subjects in the social construction of their daily lives. A family culture is developed through the combining of multiple instances of mediation, both internal (styles of intrafamily interaction; rituals around meals; consumption habits) and external (sociohistorical context, weight of institutions). In the context of family reception, the media appear to be situated in the gaps within this complex social dynamic : between the external and the internal, between the public and the private, between the local and the global.A partir d'entrevues obtenues sur le mode du « récit de vie » auprès de membres de familles québécoises, les auteurs analysent la place prise par les usages de la télévision dans le processus de construction sociale de l'identité familiale. Par les significations qu'ils attribuent aux médias et aux messages qui meublent leur environnement domestique, les membres de la cellule familiale deviennent des sujets actifs dans la construction sociale de leur quotidien. La culture familiale se fabrique à travers la conjugaison de multiples instances de médiation autant internes (styles d'interactions intrafamiliales; rituels autour des repas; habitudes de consommation) qu'externes (contexte sociohistorique, poids des institutions). Dans ce contexte de réception familiale, les médias apparaissent se situer dans les interstices de cette dynamique sociale complexe : entre l'externe et l'interne, entre le public et le privé, entre le local et le global.Proulx Serge, Laberge Marie-France. Vie quotidienne, culture télé et construction de l'identité familiale . In: Réseaux, volume 13, n°70, 1995. Médias, identité, culture des sentiments. pp. 121-140