Combined Elevation of Temperature and CO2 Impacts the Production and Sugar Composition of Aphid Honeydew.

Honeydew is the keystone of many interactions between aphids and their predators, parasitoids, and mutualistic partners. Despite the crucial importance of honeydew in aphid-ant mutualism, very few studies have investigated the potential impacts of climate change on its production and composition. Here, we quantified changes in sugar compounds and the amount of honeydew droplets released by Aphis fabae reared on Vicia faba plants under elevated temperature and/or CO2 conditions. Following the combined elevation of these two abiotic factors, we found a significant increase in the fructose content of A. fabae honeydew, accompanied by nonsignificant trends of increase in total honeydew production and melezitose content. The environmental conditions tested in this study did not significantly impact the other honeydew sugar contents. The observed changes may be related to changes in phloem composition under elevated CO2 conditions as well as to increases in aphid metabolism and sap ingestion under elevated temperatures. Although limited, such changes in aphid honeydew may concurrently reinforce ant attendance and mutualism under elevated temperature and CO2 conditions. Finally, we discuss the enhancing and counteracting effects of climate change on other biological agents (gut microorganisms, predators, and parasitoids) that interact with aphids in a complex multitrophic system.

A novel nonsense variant in REEP6 is involved in a sporadic rod-cone dystrophy case.

Rod-cone dystrophy (RCD), also called retinitis pigmentosa, is the most common form of progressive inherited retinal disorders secondary to photoreceptor degeneration. It is a genetically heterogeneous disease characterized by night blindness, followed by visual field constriction and, in most severe cases, total blindness. The aim of our study was to identify the underlying gene defect leading to severe RCD in a 60-year-old woman. The patient's DNA was investigated by targeted next generation sequencing followed by whole exome sequencing. A novel nonsense variant, c.267G>A p.(Trp89*), was identified at a homozygous state in the proband in REEP6 gene, recently reported mutated in 7 unrelated families with RCD. Further functional studies will help to understand the physiopathology associated with REEP6 mutations that may be linked to a protein trafficking defect.

ARL2BP mutations account for 0.1% of autosomal recessive rod-cone dystrophies with the report of a novel splice variant.

We report a novel ARL2BP splice site mutation after whole-exome sequencing (WES) applied to a Moroccan family including two sisters affected with autosomal recessive rod-cone dystrophy (arRCD). Subsequent analysis of 844 index cases did not reveal further pathogenic chances in ARL2BP indicating that mutations in ARL2B are a rare cause of arRCD (about 0.1%) in a large cohort of French patients.

Novel bioactive tetracycline-containing electrospun polymer fibers as a potential antibacterial dental implant coating.

The purpose of this investigation was to determine the ability of tetracycline-containing fibers to inhibit biofilm formation of peri-implantitis-associated pathogens [i.e., Porphyromonas gingivalis (Pg), Fusobacterium nucleatum (Fn), Prevotella intermedia (Pi), and Aggregatibacter actinomycetemcomitans (Aa)]. Tetracycline hydrochloride (TCH) was added to a poly(DL-lactide) [PLA], poly(ε-caprolactone) [PCL], and gelatin [GEL] polymer blend solution at distinct concentrations to obtain the following fibers: PLA:PCL/GEL (TCH-free, control), PLA:PCL/GEL + 5 % TCH, PLA:PCL/GEL + 10 % TCH, and PLA:PCL/GEL + 25 % TCH. The inhibitory effect of TCH-containing fibers on biofilm formation was assessed by colony-forming units (CFU/mL). Qualitative analysis of biofilm inhibition was done via scanning electron microscopy (SEM). Statistical significance was reported at p < 0.05. Complete inhibition of biofilm formation on the fibers was observed in groups containing TCH at 10 and 25 wt%. Fibers containing TCH at 5 wt% demonstrated complete inhibition of Aa biofilm. Even though a marked reduction in CFU/mL was observed with an increase in TCH concentration, Pi proved to be the most resilient microorganism. SEM images revealed the absence of or a notable decrease in bacterial biofilm on the TCH-containing nanofibers. Collectively, our data suggest that tetracycline-containing fibers hold great potential as an antibacterial dental implant coating.

Structure of the X-linked Kallmann syndrome gene and its homologous pseudogene on the Y chromosome.

The gene for the X-linked Kallmann syndrome (KAL), a developmental disorder characterized by hypogonadotropic hypogonadism and anosmia, maps to Xp22.3 and has a homologous locus, KALP, on Yq11. We show here that KAL consists of 14 exons spanning 120-200 kilobases that correlate with the distribution of domains in the predicted protein including four fibronectin type III repeats. The KALP locus reveals several large deletions and a number of small insertions, deletions and base substitutions which indicate it is a non-processed pseudogene. The sequence divergence between KAL and KALP in humans, and the chromosomal location of KAL homologous sequences in other primates, suggest that KALP and the steroid sulphatase pseudogene on Yq11 were involved in the same rearrangement event on the Y chromosome during primate evolution.

A non-syndrome form of neurosensory, recessive deafness maps to the pericentromeric region of chromosome 13q.

Non-syndromic, recessively inherited deafness is the most predominant form of severe inherited childhood deafness. Until now, no gene responsible for this type of deafness has been localized, due to extreme genetic heterogeneity and limited clinical differentiation. Linkage analyses using highly polymorphic microsatellite markers were performed on two consanguineous families from Tunisia affected by this form of deafness. The deafness was profound, fully penetrant and prelingual. A maximum two-point lod score of 9.88 (theta = 0.001) was found with a marker detecting a 13q locus (D13S175). Linkage was also observed to the pericentromeric 13q12 loci D13S115 and D13S143. These data map this neurosensory deafness gene to the same region of chromosome 13q as the gene for severe, childhood autosomal recessive muscular dystrophy.

The autosomal recessive isolated deafness, DFNB2, and the Usher 1B syndrome are allelic defects of the myosin-VIIA gene.

Hereditary non-syndromic profound deafness affects about 1 in 2000 children prior to language acquisition. In 80% of the cases, the mode of transmission is autosomal recessive. The number of genes involved in these recessive forms of isolated deafness (DFNB genes) has been estimated to between 30 and 100. So far, ten DFNB genes have been mapped to human chromosomes, one of which has been isolated. By linkage analysis of a single family whose members were affected with profound deafness, some of them presenting with vestibular dysfunction, DFNB2 has been mapped to chromosome 11q13 (ref. 3). The gene responsible for a form of Usher syndrome type I, USH1B, has been assigned to the same chromosomal region. Usher syndrome associates profound congenital deafness and vestibular dysfunction with retinitis pigmentosa. In the homologous murine region are located the shaker-1 mutations responsible for deafness and vestibular dysfunction. It has been demonstrated that the murine shaker-1 and human USH1B phenotypes result from mutations in the gene encoding myosin-VIIA. Based on mapping data as well as on the similarities between the phenotypes of DFNB2-affected patients and shaker-1 mouse mutants, we have proposed that a defective myosin-VIIA may also be responsible for DFNB2 (ref. 1). Sequence analysis of each of the coding exons of the myosin-VIIA gene (MYO7A) was thus undertaken in the DFNB2-affected family. In the last nucleotide of exon 15, a G to A transition was detected, a type of mutation that is known to decrease the efficiency of splicing. Accordingly, this result shows that different mutations in MYO7A result in either an isolated or a syndromic form of deafness.

A defect in harmonin, a PDZ domain-containing protein expressed in the inner ear sensory hair cells, underlies Usher syndrome type 1C.

Usher syndrome type 1 (USH1) is an autosomal recessive sensory defect involving congenital profound sensorineural deafness, vestibular dysfunction and blindness (due to progressive retinitis pigmentosa)1. Six different USH1 loci have been reported. So far, only MYO7A (USH1B), encoding myosin VIIA, has been identified as a gene whose mutation causes the disease. Here, we report a gene underlying USH1C (MIM 276904), a USH1 subtype described in a population of Acadian descendants from Louisiana and in a Lebanese family. We identified this gene (USH1C), encoding a PDZ-domain-containing protein, harmonin, in a subtracted mouse cDNA library derived from inner ear sensory areas. In patients we found a splice-site mutation, a frameshift mutation and the expansion of an intronic variable number of tandem repeat (VNTR). We showed that, in the mouse inner ear, only the sensory hair cells express harmonin. The inner ear Ush1c transcripts predicted several harmonin isoforms, some containing an additional coiled-coil domain and a proline- and serine-rich region. As several of these transcripts were absent from the eye, we propose that USH1C also underlies the DFNB18 form of isolated deafness.

Mutations in a new gene encoding a protein of the hair bundle cause non-syndromic deafness at the DFNB16 locus.

Hearing impairment affects about 1 in 1,000 children at birth. Approximately 70 loci implicated in non-syndromic forms of deafness have been reported in humans and 24 causative genes have been identified (see also http://www.uia.ac.be/dnalab/hhh). We report a mouse transcript, isolated by a candidate deafness gene approach, that is expressed almost exclusively in the inner ear. Genomic analysis shows that the human ortholog STRC (so called owing to the name we have given its protein-stereocilin), which is located on chromosome 15q15, contains 29 exons encompassing approximately 19 kb. STRC is tandemly duplicated, with the coding sequence of the second copy interrupted by a stop codon in exon 20. We have identified two frameshift mutations and a large deletion in the copy containing 29 coding exons in two families affected by autosomal recessive non-syndromal sensorineural deafness linked to the DFNB16 locus. Stereocilin is made up of 1,809 amino acids, and contains a putative signal petide and several hydrophobic segments. Using immunohistolabeling, we demonstrate that, in the mouse inner ear, stereocilin is expressed only in the sensory hair cells and is associated with the stereocilia, the stiff microvilli forming the structure for mechanoreception of sound stimulation.

Astrocytic protection of spinal motor neurons but not cortical neurons against loss of Als2/alsin function.

Three neurodegenerative diseases affecting upper and/or lower motor neurons have been associated with loss of ALS2/Alsin function: juvenile amyotrophic lateral sclerosis, primary lateral sclerosis and infantile-onset ascending hereditary spastic paralysis. The distinct neuronal vulnerability and the role of glia in these diseases remains, however, unclear. We here demonstrate that alsin-depleted spinal motor neurons can be rescued from defective survival and axon growth by co-cultured astrocytes. The astrocytic rescue is mediated by a soluble protective factor rather than by cellular contact. Cortical neurons are intrinsically as vulnerable to alsin depletion as spinal motor neurons but cannot be rescued by co-cultured astrocytes. To our knowledge, these data provide the first example of non-cell-autonomous glial effects in a recessive form of motor neuron disease and a potential rationale for the higher vulnerability of upper versus lower motor neurons in ALS2/Alsin-linked disorders.

Impact of Social Frailty on Relocation of Older Adults.

BACKGROUND: The relationship between frailty and variables such as housing are the least included in models of frailty and research on frailty or social frailty and relocation is negligible. The decision to relocate is complex and demanding for older adults with a loss of independence but little is known about what makes older adults relocate to congregated housing designated for older adults, let alone in combination with social frailty, and how they navigate this transition. OBJECTIVES: This mixed method descriptive study aims to understand the influence of social frailty for a population of French-speaking semi-independent older adults relocating to a housing continuum community. DESIGN: Semi-structured individual interviews including sociodemographic data and the PRISMA-7 Frailty Scale were conducted with recently relocated older adults. SETTING: A newly opened French-speaking housing continuum community in Eastern Canada that offers luxury apartments for independent older adults, two assisted living facilities for semi-independent older adults along with a long-term care facility. PARTICIPANTS: Twenty-nine older adults with a mean age of 85 years, mostly female, married or widowed and highly educated. MEASUREMENTS: Content analysis of the transcribed recorded interviews and descriptive statistical analyses to examine relationships between the frailty PRISMA-7 scale, answers to additional questions and the sociodemographic data. RESULTS: There was not a significant difference in the scores for socialization before and after relocation nor between prior help and current help; however, there was a significant negative correlation between help and socialization before and after relocation. Three main themes included: imposed influences, push and pull factors and post relocation. CONCLUSIONS: The results indicate that several social factors contributed to relocation and that participants were experiencing social frailty. Participants were at the crossover point of being vulnerable to experiencing additional deficits which would potentially have led to higher frailty had they not relocated.

Phorbol ester receptors and protein kinase C in primary neuronal cultures: development and stimulation of endogenous phosphorylation.

Embryonic rat neurons cultured in defined medium, essentially in the absence of glia, were highly enriched in phorbol ester receptors. The neurons displayed a single class of phorbol 12,13-dibutyrate binding sites with a maximum binding capacity, after 10 d in culture, of 18.6 pmol/mg protein and an apparent dissociation constant of 7.1 nM. Phorbol ester binding sites were associated with protein kinase C, which represented a major protein kinase activity in primary neuronal cultures. Ca2+-phosphatidylserine-sensitive phosphorylation of endogenous substrates was more marked than that observed in the presence of cyclic AMP or Ca2+ and calmodulin. Phorbol ester receptors and protein kinase C levels were critically dependent on the culture age. Thus, about a 20-fold increase in binding sites occurred during the first week in culture and was accompanied by a corresponding increase in Ca2+-phosphatidylserine-sensitive protein phosphorylation in soluble neuronal extracts. These changes largely paralleled a similar rise in phorbol ester binding during fetal development in vivo. The apparent induction of phorbol ester receptors was specific relative to other cellular proteins and could be inhibited by cycloheximide or Actinomycin D. Phosphorylation of endogenous substrates in intact cultured neurons paralleled the age-dependent increase in protein kinase C. Furthermore, 32P incorporation into several major phosphoproteins was markedly augmented by treating the neuronal cultures with phorbol esters. Such phosphorylation events may provide a clue to the significance of protein kinase C in developing neurons.

Solution structure of a bovine immunodeficiency virus Tat-TAR peptide-RNA complex.

The Tat protein of bovine immunodeficiency virus (BIV) binds to its target RNA, TAR, and activates transcription. A 14-amino acid arginine-rich peptide corresponding to the RNA-binding domain of BIV Tat binds specifically to BIV TAR, and biochemical and in vivo experiments have identified the amino acids and nucleotides required for binding. The solution structure of the RNA-peptide complex has now been determined by nuclear magnetic resonance spectroscopy. TAR forms a virtually continuous A-form helix with two unstacked bulged nucleotides. The peptide adopts a beta-turn conformation and sits in the major groove of the RNA. Specific contacts are apparent between critical amino acids in the peptide and bases and phosphates in the RNA. The structure is consistent with all biochemical data and demonstrates ways in which proteins can recognize the major groove of RNA.

Structure of the A site of Escherichia coli 16S ribosomal RNA complexed with an aminoglycoside antibiotic.

Aminoglycoside antibiotics that bind to 30S ribosomal A-site RNA cause misreading of the genetic code and inhibit translocation. The aminoglycoside antibiotic paromomycin binds specifically to an RNA oligonucleotide that contains the 30S subunit A site, and the solution structure of the RNA-paromomycin complex was determined by nuclear magnetic resonance spectroscopy. The antibiotic binds in the major groove of the model A-site RNA within a pocket created by an A-A base pair and a single bulged adenine. Specific interactions occur between aminoglycoside chemical groups important for antibiotic activity and conserved nucleotides in the RNA. The structure explains binding of diverse aminoglycosides to the ribosome, their specific activity against prokaryotic organisms, and various resistance mechanisms, and provides insight into ribosome function.

Bile acids: natural ligands for an orphan nuclear receptor.

Bile acids regulate the transcription of genes that control cholesterol homeostasis through molecular mechanisms that are poorly understood. Physiological concentrations of free and conjugated chenodeoxycholic acid, lithocholic acid, and deoxycholic acid activated the farnesoid X receptor (FXR; NR1H4), an orphan nuclear receptor. As ligands, these bile acids and their conjugates modulated interaction of FXR with a peptide derived from steroid receptor coactivator 1. These results provide evidence for a nuclear bile acid signaling pathway that may regulate cholesterol homeostasis.

Social and societal implications of frailty, including impact on Canadian healthcare systems.

Frailty has many social and societal implications. Social circumstances are key both as contributors to frail older adults' health outcomes and as practical facilitators or barriers to intervention and supports. Frailty also has important societal implications for health systems and social care policy. In this discussion paper, we use a social ecology framework to consider the social and societal implications and impact of frailty at each level, from the individual, through relationships with family and friend caregivers, institutions, health systems, neighborhoods and communities, to society at large. We conclude by arguing that attention to these issues at a policy level is critical. We identify three target actions: 1) Social dimensions of frailty should be systematically considered when frailty is assessed. 2) Action is needed at the level of policies and programs to improve support for caregivers. 3) Policy review across all portfolios will benefit from a social frailty lens.

Frozen storage stability of antioxidant-treated raw restructured beef steaks made from mature cows.

Previous research has shown that beef quality decreased with the age of cattle. In this study, beef trimmings from nine mature cows (n=9), equally representing three animal age groups (2-4, 6-8, and 10-12yr), were restructured into steaks formulated with propyl gallate, alone or in combination with a beefy flavoring agent, to enhance palatability and stability during 6months of frozen storage at -29°C. Lipid oxidation, rancidity, and loss of beefy flavor in restructured steaks during extended storage were reduced by propyl gallate. The beefy flavoring agent inclusion masked mature, forage-fed beef off-flavors, intensified beefy flavor, and improved steak tenderness, juiciness and cooking yield. Thus, the combination of propyl gallate and beefy flavoring offers an effective means to enhance the palatability and storage stability of restructured beef prepared from mature cows.

Clusterin facilitates apoptotic cell clearance and prevents apoptotic cell-induced autoimmune responses.

Clusterin (Clu), an extracellular chaperone, exhibits characteristics of soluble innate immunity receptors, as assessed by its ability to bind some bacteria strains. In this study, we report that Clu also binds specifically to late apoptotic cells but not to live, early apoptotic, or necrotic cells. Histones, which accumulate on blebs during the apoptotic process, represent privileged Clu-binding motifs at the surface of late apoptotic cells. As a consequence, Clu potentiates, both in vitro and in vivo, the phagocytosis of late apoptotic cells by macrophages. Moreover, the increased phagocytosis of late apoptotic cells induced by Clu favors the presentation and cross-presentation of apoptotic cell-associated antigens. Finally, we observed that, in a model of apoptotic cell-induced autoimmunity, and relative to control mice, Clu(-/-) mice develop symptoms of autoimmunity, including the generation of anti-dsDNA antibodies, deposition of immunoglobulins and complement components within kidneys, and splenomegaly. These results identify Clu as a new molecule partner involved in apoptotic cell efferocytosis and suggest a protective role for Clu in inflammation and autoimmune diseases.

A novel N-aryl tyrosine activator of peroxisome proliferator-activated receptor-gamma reverses the diabetic phenotype of the Zucker diabetic fatty rat.

The discovery that peroxisome proliferator-activated receptor (PPAR)-gamma was the molecular target of the thiazolidinedione class of antidiabetic agents suggested a key role for PPAR-gamma in the regulation of carbohydrate and lipid metabolism. Through the use of high-throughput biochemical assays, GW1929, a novel N-aryl tyrosine activator of human PPAR-gamma, was identified. Chronic oral administration of GW1929 or troglitazone to Zucker diabetic fatty (ZDF) rats resulted in dose-dependent decreases in daily glucose, free fatty acid, and triglyceride exposure compared with pretreatment values, as well as significant decreases in glycosylated hemoglobin. Whole body insulin sensitivity, as determined by the euglycemic-hyperinsulinemic clamp technique, was significantly increased in treated animals. Comparison of the magnitude of glucose lowering as a function of serum drug concentrations showed that GW1929 was 2 orders of magnitude more potent than troglitazone in vivo. These data were consistent with the relative in vitro potencies of GW1929 and troglitazone. Isolated perfused pancreas studies performed at the end of the study confirmed that pancreata from vehicle-treated rats showed no increase in insulin secretion in response to a step change in glucose from 3 to 10 mmol/l. In contrast, pancreata from animals treated with GW1929 showed a first- and second-phase insulin secretion pattern. Consistent with the functional data from the perfusion experiments, animals treated with the PPAR-gamma agonist had more normal islet architecture with preserved insulin staining compared with vehicle-treated ZDF rats. This is the first demonstration of in vivo efficacy of a novel nonthiazolidinedione identified as a high-affinity ligand for human PPAR-gamma. The increased potency of GW1929 compared with troglitazone both in vitro and in vivo may translate into improved clinical efficacy when used as monotherapy in type 2 diabetic patients. In addition, the significant improvement in daily meal tolerance may impact cardiovascular risk factor management in these patients.