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1.
Invest Ophthalmol Vis Sci ; 64(13): 37, 2023 10 03.
Article in English | MEDLINE | ID: mdl-37870847

ABSTRACT

Purpose: The lens epithelium maintains the overall health of the organ. We used single-cell RNA sequencing (scRNA-seq) technology to assess transcriptional heterogeneity between cells in the postnatal day 2 (P2) epithelium and identify distinct epithelial cell subtypes. Analysis of these data was used to better understand lens growth, differentiation, and homeostasis on P2. Methods: scRNA-seq on P2 mouse lenses was performed using the 10x Genomics Chromium Single Cell 3' Kit (v3.1) and short-read Illumina sequencing. Sequence alignment and preprocessing of data were conducted using 10x Genomics Cell Ranger software. Seurat was employed for preprocessing, quality control, dimensionality reduction, and cell clustering, and Monocle was utilized for trajectory analysis to understand the developmental progression of the lens cells. CellChat and GO analyses were used to explore cell-cell communication networks and signaling interactions. Results: Lens epithelial cells (LECs) were divided into seven subclusters, classified by specific gene markers. The expression of crystallin, cell-cycle, and metabolic genes was not uniform, indicating distinct functional roles of LECs. Trajectory analysis predicted a bifurcation of differentiating and cycling cells from an Igfbp5+ progenitor pool. We also identified heterogeneity in signaling molecules and pathways, suggesting that cycling and progenitor subclusters have prominent roles in coordinating crosstalk. Conclusions: scRNA-seq corroborated many known markers of epithelial differentiation and proliferation while providing further insight into the pathways and genes directing these processes. Interestingly, we demonstrated that the developing epithelium can be divided into distinct subpopulations. These clusters reflect the transcriptionally diverse roles of the epithelium in proliferation, signaling, and maintenance.


Subject(s)
Lens, Crystalline , Animals , Mice , Lens, Crystalline/metabolism , Epithelium , Epithelial Cells/metabolism , Cell Differentiation , Sequence Analysis, RNA
2.
Contemp Clin Trials Commun ; 19: 100580, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32548333

ABSTRACT

INTRODUCTION: Rice bran arabinoxylan compound (RBAC) is a nutraceutical for enhancing a depleted immune system during and after cancer treatment. This pilot feasibility trial aims to evaluate the effects of RBAC on cancer patients' quality of life during active treatment, compared to placebo, using a validated questionnaire. Other outcome measures include changes in inflammatory and nutritional status, cytokine profile, and gut microbiota. METHODS/DESIGN: The study will recruit 50 participants from a regional cancer center in Australia. Patients aged 18-70, diagnosed with solid organ cancers stage II and above, and currently undergoing active systemic therapies, are eligible. Random allocation of participants into two groups is stratified based on metastatic status and treatment type. The dosage is either 3 g/day of RBAC or placebo in identical packaging. The participants, study coordinator, and treating oncologists are blinded to the interventions. Data collections are at baseline and at four follow-up sessions, which are six weeks apart (24 weeks). Statistical analysis will involve a protected p-value with multiple dependent values and analyzed by ANOVA with repeated measures on the occasion of testing and with both a full Bonferroni or Sidak corrections applied to protect against Type I errors. Any observed significance warrants further analysis with pairwise comparisons. Analysis of covariance will also be performed to assess any influence of the demographic data, cancer diagnosis, as well as changes in physical activity, dietary habits, and complementary medicine usage. Comparisons of gut microbiota will be based on the analysis of the fecal microbiome using 16S ribosomal ribonucleic acid amplicon sequencing. The proposed research timeline is from October 2018 to May 2022. TRIAL REGISTRATION: ANZCTR. Reg No: ACTRN12619000562178p.

3.
Proc Natl Acad Sci U S A ; 117(7): 3858-3866, 2020 02 18.
Article in English | MEDLINE | ID: mdl-32015129

ABSTRACT

The accepted role of the protein Kv2.1 in arterial smooth muscle cells is to form K+ channels in the sarcolemma. Opening of Kv2.1 channels causes membrane hyperpolarization, which decreases the activity of L-type CaV1.2 channels, lowering intracellular Ca2+ ([Ca2+]i) and causing smooth muscle relaxation. A limitation of this model is that it is based exclusively on data from male arterial myocytes. Here, we used a combination of electrophysiology as well as imaging approaches to investigate the role of Kv2.1 channels in male and female arterial myocytes. We confirmed that Kv2.1 plays a canonical conductive role but found it also has a structural role in arterial myocytes to enhance clustering of CaV1.2 channels. Less than 1% of Kv2.1 channels are conductive and induce membrane hyperpolarization. Paradoxically, by enhancing the structural clustering and probability of CaV1.2-CaV1.2 interactions within these clusters, Kv2.1 increases Ca2+ influx. These functional impacts of Kv2.1 depend on its level of expression, which varies with sex. In female myocytes, where expression of Kv2.1 protein is higher than in male myocytes, Kv2.1 has conductive and structural roles. Female myocytes have larger CaV1.2 clusters, larger [Ca2+]i, and larger myogenic tone than male myocytes. In contrast, in male myocytes, Kv2.1 channels regulate membrane potential but not CaV1.2 channel clustering. We propose a model in which Kv2.1 function varies with sex: in males, Kv2.1 channels control membrane potential but, in female myocytes, Kv2.1 plays dual electrical and CaV1.2 clustering roles. This contributes to sex-specific regulation of excitability, [Ca2+]i, and myogenic tone in arterial myocytes.


Subject(s)
Arteries/metabolism , Calcium Channels, L-Type/metabolism , Muscle, Smooth, Vascular/metabolism , Myocytes, Smooth Muscle/metabolism , Shab Potassium Channels/metabolism , Animals , Calcium/metabolism , Calcium Channels, L-Type/genetics , Cells, Cultured , Female , Male , Membrane Potentials , Mice, Inbred C57BL , Mice, Knockout , Shab Potassium Channels/genetics
4.
Transl Psychiatry ; 8(1): 165, 2018 08 23.
Article in English | MEDLINE | ID: mdl-30139969

ABSTRACT

The effect of six different traumatic stress protocols on the transcriptome of the rat adrenal gland was examined using RNA sequencing. These protocols included chronic variable stress, chronic shock, social defeat and social isolation. The response of the transcriptome to stress suggested that there are genes that respond in a universal or stress modality-independent manner, as well as genes that respond in a stress modality-specific manner. Using a small number of the genes selected from the modality-independent set of stress-sensitive genes, a sensitive and robust measure of chronic stress exposure was developed. This stress-sensitive gene expression (SSGE) index could detect chronic traumatic stress exposure in a wide range of different stress models in a manner that was relatively independent of the modality of stress exposure and that paralleled the intensity of stress exposure in a dose-dependent manner. This measure could reliably distinguish control and stressed individuals in the case of animals exposed to the most intense stress protocols. The response of a subset of the modality-specific genes could also distinguish some types of stress exposure, based solely on changes in the pattern of gene expression. The results suggest that it is possible to develop diagnostic measures of traumatic stress exposure based solely on changes in the level of expression of a relatively small number of genes.


Subject(s)
Stress, Psychological/genetics , Stress, Psychological/psychology , Transcriptome , Animals , Behavior Rating Scale , Behavior, Animal , Disease Models, Animal , Male , Rats , Rats, Sprague-Dawley , Sequence Analysis, RNA
5.
Waste Manag ; 76: 180-189, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29599024

ABSTRACT

There is low utilisation of plastic waste in the Nordic region and only a fraction of plastic materials go back into production processes through reuse and recycling practices. This paper aims to increase knowledge concerning factors that inhibit demand for recycled plastics, and to identify critical barriers for plastic recycling across the regional plastics value chain. A literature review and targeted interviews with key actors across the plastics value chain enabled the mapping of interactions between the major actors and identified hotspots that act as barriers to the flow of plastic materials. Barriers identified include the lack of both supply and demand of recycled plastic and are mainly attributed to the fragmented market of secondary materials. The main hotspots identified are the low demand due to price considerations, insufficient traceability and transparency in value chain transactions, and general design deficiencies in the recyclability of products. Value chain coordination is considered as the most important intervention by the interviewees, followed by the need for increased investment in innovation and technology development. Complementary measures that could counteract the identified barriers include public procurement for resource efficiency, ban on the incineration of recyclable materials, and specifications on the design of plastic products for reducing the number of different polymers, and the number and usage of additives.


Subject(s)
Plastics , Recycling , Incineration , Polymers , Scandinavian and Nordic Countries
6.
Prog Biophys Mol Biol ; 122(3): 165-186, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27702655

ABSTRACT

Evolution has acted to shape the action potential in different regions of the heart in order to produce a maximally stable and efficient pump. This has been achieved by creating regional differences in ion channel expression levels within the heart as well as differences between equivalent cardiac tissues in different species. These region- and species-dependent differences in channel expression are established by regulatory evolution, evolution of the regulatory mechanisms that control channel expression levels. Ion channel auxiliary subunits are obvious targets for regulatory evolution, in order to change channel expression levels and/or modify channel function. This review focuses on the transmural gradients of ion channel expression in the heart and the role that regulation of auxiliary subunit expression plays in generating and shaping these gradients.


Subject(s)
Gene Expression Regulation , Ion Channels/genetics , Ion Channels/metabolism , Protein Subunits/genetics , Animals , Electrophysiological Phenomena , Humans , Potassium/metabolism
7.
Waste Manag Res ; 34(9): 947-56, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27357560

ABSTRACT

The Waste Framework Directive obliged European Union Member States to set up separate collection systems to promote high quality recycling for at least paper, metal, plastic and glass by 2015. As implementation of the requirement varies across European Union Member States, the European Commission contracted BiPRO GmbH/Copenhagen Resource Institute to assess the separate collection schemes in the 28 European Union Member States, focusing on capital cities and on metal, plastic, glass (with packaging as the main source), paper/cardboard and bio-waste. The study includes an assessment of the legal framework for, and the practical implementation of, collection systems in the European Union-28 Member States and an in depth-analysis of systems applied in all capital cities. It covers collection systems that collect one or more of the five waste streams separately from residual waste/mixed municipal waste at source (including strict separation, co-mingled systems, door-to-door, bring-point collection and civic amenity sites). A scoreboard including 13 indicators is elaborated in order to measure the performance of the systems with the capture rates as key indicators to identify best performers. Best performance are by the cities of Ljubljana, Helsinki and Tallinn, leading to the key conclusion that door-to-door collection, at least for paper and bio-waste, and the implementation of pay-as-you-throw schemes results in high capture and thus high recycling rates of packaging and other municipal waste.


Subject(s)
European Union , Product Packaging , Recycling/methods , Solid Waste/analysis , Waste Management/methods , Recycling/legislation & jurisprudence , Refuse Disposal/legislation & jurisprudence , Waste Management/legislation & jurisprudence
8.
Am Ann Deaf ; 160(1): 24-35, 2015.
Article in English | MEDLINE | ID: mdl-26004973

ABSTRACT

Children who are d/Deaf and hard of hearing (DHH) grow up in environments influenced by their parents' attitudes, which may facilitate or impede these children's development and participation (World Health Organization, 2007). The attitudes of 152 Australian parents of DHH children ages 3 years 7 months to 9 years 5 months (M = 6 years 5 months) were investigated with the Opinions About Deaf People Scale (Berkay, Gardner, & Smith, 1995a). The parents' responses showed very positive attitudes toward the capabilities of DHH adults, particularly on items describing their intellectual and vocational capabilities. Parents' responses to most of the items on the scale were positively skewed, raising questions about its validity as a research tool when used with parents of DHH children. The study findings suggest that for these children, parents' attitudes may facilitate rather than present an environmental barrier to their development.


Subject(s)
Attitude , Deafness/psychology , Parents/psychology , Persons With Hearing Impairments/psychology , Adult , Australia , Child, Preschool , Environment , Female , Humans , Intelligence , Male , Middle Aged , Occupations , Reproducibility of Results , Surveys and Questionnaires , Young Adult
9.
PLoS One ; 10(4): e0120785, 2015.
Article in English | MEDLINE | ID: mdl-25875483

ABSTRACT

It has been suggested that optimization of either axonal conduction velocity or the energy efficiency of action potential conduction predominates in the selection of voltage-gated sodium conductance levels in the squid axon. A population genetics model of channel gene regulatory function was used to examine the role of these and other evolutionary forces on the selection of both sodium and potassium channel expression levels. In this model, the accumulating effects of mutations result in degradation of gene regulatory function, causing channel gene expression to fall to near-zero in the absence of positive selection. In the presence of positive selection, channel expression levels fall to the lowest values consistent with the selection criteria, thereby establishing a selection-mutation balance. Within the parameter space of sodium and potassium conductance values, the physiological performance of the squid axon model showed marked discontinuities associated with conduction failure and excitability. These discontinuities in physiological function may produce fitness cliffs. A fitness cliff associated with conduction failure, combined with the effects of phenotypic noise, can account for the selection of sodium conductance levels, without considering either conduction velocity or metabolic cost. A fitness cliff associated with a transition in axonal excitability, combined with phenotypic noise, can explain the selection of potassium channel expression levels. The results suggest that voltage-gated ion channel expression will fall to low levels, consistent with key functional constraints, even in the absence of positive selection for energy efficiency. Channel expression levels and individual variation in channel expression within the population can be explained by regulatory evolution in combination with genetic variation in regulatory function and phenotypic noise, without resorting to more complex mechanisms, such as activity-dependent homeostasis. Only a relatively small region of the large, nominally isofunctional parameter space for channel expression will normally be occupied, because of the effects of mutation.


Subject(s)
Axons/physiology , Biological Evolution , Decapodiformes/physiology , Potassium Channels/genetics , Sodium Channels/genetics , Action Potentials , Animals , Decapodiformes/genetics , Evolution, Molecular , Gene Regulatory Networks , Models, Genetic , Mutation , Neural Conduction , Potassium Channels/metabolism , Sodium Channels/metabolism
10.
Front Pharmacol ; 6: 9, 2015.
Article in English | MEDLINE | ID: mdl-25691868

ABSTRACT

4-phenylbutyrate (4-PB) has been shown to increase the protein content in a number of cells types. One such protein is Connexin43 (Cx43). We show here that 4-phenylbutyrate exposure results in significantly elevated cell to cell coupling, as determined by dual whole cell patch clamp. Incubation with 5 mM 4PB for 24 h or more nearly doubles junctional conductance. Interestingly, mRNA levels for Cx43 declined with exposure to 4-PB while western blot analysis revealed not significant change in protein levels. These data are most consistent with stabilization of the existing Cx43 pool or alterations in the number of functional channels within an existing pool of active and silent channels. These data represent a baseline for testing the efficacy of increased connexin mediated coupling in a variety of multicellular functions including erectile function.

11.
Lang Speech Hear Serv Sch ; 45(3): 234-47, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24686735

ABSTRACT

PURPOSE: The authors sought to investigate the influence of a comprehensive range of factors on the decision making of caregivers of children with hearing loss regarding the use of speech, the use of sign, spoken language multilingualism, and spoken language choice. This is a companion article to the qualitative investigation described in Crowe, Fordham, McLeod, and Ching (2014). METHOD: Through a questionnaire, 177 caregivers of 157 Australian children with hearing loss (ages 3;5 to 9;4 [years;months], Mage = 6;6) rated the importance of a range of potential influences on their decision making regarding their children's communication. The majority of children were reported to use speech (96.6%) as part or all of their communication system, with fewer children reported to use sign (20.9%). Few children used more than one spoken language (8.3%). RESULTS: Proportional analyses and exploratory factor analyses were conducted. Overall, caregivers' decisions were influenced by their children's audiological and intervention characteristics, communication with those around them, community participation, access to intervention and education services in English, and concerns about their children's future lives. The advice of speech-language pathologists, audiologists, and specialist teachers was more important to caregivers than advice from medical practitioners and nonprofessionals. CONCLUSION: Caregivers' decision making regarding communication mode and language use is influenced by factors that are not equally weighted and that relate to child, family, community, and advice from others. Knowledge of these factors can assist professionals in supporting caregivers making choices regarding communication.


Subject(s)
Caregivers/psychology , Decision Making , Hearing Loss/rehabilitation , Multilingualism , Sign Language , Speech , Australia , Child , Child, Preschool , Female , Humans , Language , Male , Speech-Language Pathology , Surveys and Questionnaires
12.
Child Lang Teach Ther ; 29(1): 111-129, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23519446

ABSTRACT

Understanding the relationship between children's cultural and linguistic diversity and child, caregiver, and environmental characteristics is important to ensure appropriate educational expectations and provisions. As part of the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study, children's caregivers and educators completed questionnaires on demographic characteristics, including the communication mode (oral, manual, or mixed) and languages used in home and early educational environments. This article reports an exploratory analysis to examine factors associated with language use and communication mode of children at 3 years of age. A Chi Square Automatic Interaction Detector (CHAID) analysis was performed on data from 406 children to examine factors influencing communication mode and oral language use. The factor that most influenced children's communication mode at home was the communication mode used by their female caregiver. Children's communication mode in their early education environment was most related to the communication mode they used at home, and then related to the presence of additional needs in the children, female caregivers' level of education and the male caregivers' use of languages other than English (LOTEs). A second exploratory CHAID analysis of data for children from multilingual families (n = 106) indicated that female caregivers' use of English at home significantly influenced whether children used a LOTE at home. Finally, the use of a LOTE at home was associated with the use of a LOTE in the early education environment. These findings serve as an initial description of the factors that were associated with the communication mode and language use of children with hearing loss.

13.
Proc Natl Acad Sci U S A ; 109(5): 1601-6, 2012 Jan 31.
Article in English | MEDLINE | ID: mdl-22307618

ABSTRACT

Scaling of cardiac electrophysiology with body mass requires large changes in the ventricular action potential duration and heart rate in mammals. These changes in cellular electrophysiological function are produced by systematic and coordinated changes in the expression of multiple ion channel and transporter genes. Expression of one important potassium current, the transient outward current (I(to)), changes significantly during mammalian evolution. Changes in I(to) expression are determined, in part, by variation in the expression of an obligatory auxiliary subunit encoded by the KChIP2 gene. The KChIP2 gene is expressed in both cardiac myocytes and neurons and transcription in both cell types is initiated from the same CpG island promoter. Species-dependent variation of KChIP2 expression in heart is mediated by the evolution of the cis-regulatory function of this gene. Surprisingly, the major locus of evolutionary change for KChIP2 gene expression in heart lies within the CpG island core promoter. The results demonstrate that CpG island promoters are not simply permissive for gene expression but can also contribute to tissue-selective expression and, as such, can function as an important locus for the evolution of cis-regulatory function. More generally, evolution of the cis-regulatory function of voltage-gated ion channel genes appears to be an effective and efficient way to modify channel expression levels to optimize electrophysiological function.


Subject(s)
CpG Islands , Kv Channel-Interacting Proteins/genetics , Myocardium/metabolism , Promoter Regions, Genetic , Amino Acid Sequence , Animals , Base Sequence , DNA Probes , Gene Expression Regulation , Guinea Pigs , Kv Channel-Interacting Proteins/chemistry , Mice , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction , RNA, Messenger/genetics , Rats , Sequence Homology, Amino Acid , Transcription, Genetic
14.
J Physiol ; 589(Pt 13): 3275-88, 2011 Jul 01.
Article in English | MEDLINE | ID: mdl-21521762

ABSTRACT

Mechanisms that contribute to maintaining expression of functional ion channels at relatively constant levels following perturbations of channel biosynthesis are likely to contribute significantly to the stability of electrophysiological systems in some pathological conditions. In order to examine the robustness of L-type calcium current expression, the response to changes in Ca²âº channel Cav1.2 gene dosage was studied in adult mice. Using a cardiac-specific inducible Cre recombinase system, Cav1.2 mRNA was reduced to 11 ± 1% of control values in homozygous floxed mice and the mice died rapidly (11.9 ± 3 days) after induction of gene deletion. In these homozygous knockout mice, echocardiographic analysis showed that myocardial contractility was reduced to 14 ± 1% of control values shortly before death. For these mice, no effective compensatory changes in ion channel gene expression were triggered following deletion of both Cav1.2 alleles, despite the dramatic decay in cardiac function. In contrast to the homozygote knockout mice, following knockout of only one Cav1.2 allele, cardiac function remained unchanged, as did survival.Cav1.2mRNAexpression in the left ventricle of heterozygous knockout mice was reduced to 58 ± 3% of control values and there was a 21 ± 2% reduction in Cav1.2 protein expression. There was no significant reduction in L-type Ca²âº current density in these mice. The results are consistent with a model of L-type calcium channel biosynthesis in which there are one or more saturated steps, which act to buffer changes in both total Cav1.2 protein and L-type current expression.


Subject(s)
Calcium Channels, L-Type/deficiency , Gene Expression Regulation/genetics , Genetic Carrier Screening , Myocytes, Cardiac/physiology , Age Factors , Alleles , Animals , Calcium Channels, L-Type/biosynthesis , Calcium Channels, L-Type/genetics , Female , Gene Dosage/genetics , Genetic Carrier Screening/methods , Humans , Male , Mice , Mice, Knockout , Mice, Transgenic , Mutation/genetics
15.
FASEB J ; 25(3): 851-62, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21084696

ABSTRACT

In vitro models of cardiac hypertrophy focus exclusively on applying "external" dynamic signals (electrical, mechanical, and chemical) to achieve a hypertrophic state. In contrast, here we set out to demonstrate the role of "self-organized" cellular architecture and activity in reprogramming cardiac cell/tissue function toward a hypertrophic phenotype. We report that in neonatal rat cardiomyocyte culture, subtle out-of-plane microtopographic cues alter cell attachment, increase biomechanical stresses, and induce not only structural remodeling, but also yield essential molecular and electrophysiological signatures of hypertrophy. Increased cell size and cell binucleation, molecular up-regulation of released atrial natriuretic peptide, altered expression of classic hypertrophy markers, ion channel remodeling, and corresponding changes in electrophysiological function indicate a state of hypertrophy on par with other in vitro and in vivo models. Clinically used antihypertrophic pharmacological treatments partially reversed hypertrophic behavior in this in vitro model. Partial least-squares regression analysis, combining gene expression and functional data, yielded clear separation of phenotypes (control: cells grown on flat surfaces; hypertrophic: cells grown on quasi-3-dimensional surfaces and treated). In summary, structural surface features can guide cardiac cell attachment, and the subsequent syncytial behavior can facilitate trophic signals, unexpectedly on par with externally applied mechanical, electrical, and chemical stimulation.


Subject(s)
Cardiomegaly , Myocardial Contraction/physiology , Myocytes, Cardiac/cytology , Myocytes, Cardiac/physiology , Signal Transduction/physiology , Animals , Animals, Newborn , Atrial Natriuretic Factor/genetics , Atrial Natriuretic Factor/metabolism , Cardiomegaly/metabolism , Cardiomegaly/pathology , Cardiomegaly/physiopathology , Cell Adhesion/physiology , Cell Shape/physiology , Cells, Cultured , Electric Stimulation , Genetic Markers , Mechanotransduction, Cellular/physiology , Myocytes, Cardiac/drug effects , Natriuretic Peptide, Brain/pharmacology , Phenotype , Physical Stimulation , Rats , Stimulation, Chemical , Tissue Scaffolds
16.
Biochem Cell Biol ; 87(6): 963-74, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19935882

ABSTRACT

Many mitochondrial and chloroplast proteins are encoded in the nucleus and subsequently imported into the organelles via active protein transport systems. While usually highly specific, some proteins are dual-targeted to both organelles. In tobacco (Nicotiana tabacum L.), the cDNA encoding the mitochondrial isoform of NADP+-dependent isocitrate dehydrogenase (NADP+-ICDH) contains two translational ATG start sites, suggesting the possibility of tandem targeting signals. In this work, the putative mitochondrial and chloroplastic targeting signals from NADP+-ICDH were fused to a yellow fluorescent protein (YFP) reporter to generate a series of constructs and introduced into tobacco leaves by Agrobacterium-mediated transient transformation. The subsequent sub-cellular locations of the ICDH:YFP fusion proteins were then examined using confocal microscopy. Constructs predicted to be targeted to the chloroplast all localized to the chloroplast. However, this was not the case for all of the constructs that were predicted to be mitochondrial targeted. Although some constructs localized to mitochondria as expected, others appeared to be chloroplast localized. This was attributed to an additional 50 amino acid residues of the mature NADP+-ICDH protein that were present in those constructs, generated from either 'Xanthi' or 'Petit Havana' cultivars of tobacco. The results of this study raise interesting questions regarding the targeting and processing of organellar isoforms of NADP+-ICDH.


Subject(s)
Chloroplasts/enzymology , Isocitrate Dehydrogenase , Isoenzymes , Mitochondria/enzymology , Nicotiana , Plant Proteins , Protein Sorting Signals , Amino Acid Sequence , Isocitrate Dehydrogenase/genetics , Isocitrate Dehydrogenase/metabolism , Isoenzymes/genetics , Isoenzymes/metabolism , Molecular Sequence Data , Plant Proteins/genetics , Plant Proteins/metabolism , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Sequence Alignment , Nicotiana/cytology , Nicotiana/enzymology
17.
Evol Dev ; 11(5): 610-8, 2009.
Article in English | MEDLINE | ID: mdl-19754717

ABSTRACT

Cellular electrophysiological systems, like developmental systems, appear to evolve primarily by means of regulatory evolution. It is suggested that electrophysiological systems share two key features with developmental systems that account for this dependence on regulatory evolution. For both systems, structural evolution has the potential to create significant problems of pleiotropy and both systems are predominantly computational in nature. It is concluded that the relative balance of physical and computational tasks that a biological system has to perform, combined with the probability that these tasks may have to change significantly during the course of evolution, will be major factors in determining the relative mix of regulatory and structural evolution that is observed for a given system. Physiological systems that directly interface with the environment will almost always perform some low-level physical task. In the majority of cases this will require evolution of protein function in order for the tasks themselves to evolve. For complex physiological systems a large fraction of their function will be devoted to high-level control functions that are predominantly computational in nature. In most cases regulatory evolution will be sufficient in order for these computational tasks to evolve.


Subject(s)
Cell Physiological Phenomena , Evolution, Molecular , Gene Expression Regulation , Animals , Electrophysiology , Humans
18.
Physiol Genomics ; 35(3): 262-72, 2008 Nov 12.
Article in English | MEDLINE | ID: mdl-18765860

ABSTRACT

The relative importance of regulatory versus structural evolution for the evolution of different biological systems is a subject of controversy. The primacy of regulatory evolution in the diversification of morphological traits has been promoted by many evolutionary developmental biologists. For physiological traits, however, the role of regulatory evolution has received less attention or has been considered to be relatively unimportant. To address this issue for electrophysiological systems, we examined the importance of regulatory and structural evolution in the evolution of the electrophysiological function of cardiac myocytes in mammals. In particular, two related phenomena were studied: the change in action potential morphology in small mammals and the scaling of action potential duration across mammalian phylogeny. In general, the functional properties of the ion channels involved in ventricular action potential repolarization were found to be relatively invariant. In contrast, there were large changes in the expression levels of multiple ion channel and transporter genes. For the Kv2.1 and Kv4.2 potassium channel genes, which are primary determinants of the action potential morphology in small mammals, the functional properties of the proximal promoter regions were found to vary in concordance with species-dependent differences in mRNA expression, suggesting that evolution of cis-regulatory elements is the primary determinant of this trait. Scaling of action potential duration was found to be a complex phenomenon, involving changes in the expression of a large number of channels and transporters. In this case, it is concluded that regulatory evolution is the predominant mechanism by which the scaling is achieved.


Subject(s)
Biological Evolution , Electrophysiology/methods , Muscle Cells/physiology , Potassium Channels, Voltage-Gated/physiology , Action Potentials/physiology , Animals , Body Weight , Cattle , Ferrets , Guinea Pigs , Heart Rate , Humans , Mice , Muscle Cells/cytology , Myocardium/cytology , Rabbits , Rats , Species Specificity
19.
Clin Linguist Phon ; 22(4-5): 335-44, 2008.
Article in English | MEDLINE | ID: mdl-18415733

ABSTRACT

A survey of 277 speech language pathologists (SLPs) investigated beliefs and practice regarding parents' involvement in service planning and delivery for children with speech impairment. Although the SLPs frequently involved parents in service delivery for speech intervention, parental involvement in service planning was less frequent. SLPs working in educational settings involved parents to a lesser extent than SLPs working in health settings and private practice. More experienced SLPs involved parents less in decision-making. A gap between the SLPs' beliefs and practice was found, with stated beliefs not always reflecting practice. 40% of respondents were unhappy with the level of parental involvement and perceived workplace, personal and parental barriers to working effectively with parents. Although the SLPs indicated that they believed in and used family-centered practices, beliefs and practice regarding parent decision-making were therapist- rather than family-centered.


Subject(s)
Parents , Professional-Family Relations , Speech Disorders/therapy , Speech Therapy/methods , Articulation Disorders/diagnosis , Articulation Disorders/therapy , Australia , Child , Cooperative Behavior , Culture , Decision Making , Education, Special , Female , Humans , Male , Patient Care Planning , Phonetics , Private Practice , Speech Disorders/diagnosis , Surveys and Questionnaires
20.
Int J Lang Commun Disord ; 42 Suppl 1: 37-59, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17454236

ABSTRACT

BACKGROUND: Prevalence data are of interest to health professionals and educators to assist in the planning of service delivery, allow for the calculation of the level of impact of intervention, and allow for the consideration of the boundaries between typical development and impairment. AIMS: To determine the prevalence of children with communication disorders and other learning needs as identified by their teachers within all primary and secondary schools in an Australian school district over a 3-year period. METHODS & PROCEDURES: Children with learning needs were identified from 14,514 students in the first year (wave 1) and the 14,533 students 2 years later (wave 2). Children were identified via a four-phased data-collection process designed to reduce selection and misclassification bias. Identification included teacher training, teacher referral, confirmation by documentation from relevant professionals including speech and language therapists, audiologists, psychologists and doctors, and verification by the school district learning needs advisors. OUTCOMES & RESULTS: Overall 5309 students were identified as having some area of learning need in the first year and 4845 students were identified 2 years later. In order of prevalence, the areas of learning need were: specific learning difficulty (17.93% in wave 1; 19.10% in wave 2), communication disorder (13.04%; 12.40%), English as a second or other language (9.16%; 5.80%), behavioural/emotional difficulty (8.16%; 6.10%), early achiever/advanced learner (7.30%; 5.50%), physical/medical disability (1.52%; 1.40%), intellectual disability (1.38%; 1.20%), hearing impairment (0.96%; 0.80%), and visual impairment (0.16%; 0.30%). The male:female ratio for all children was 1.57:1 (wave 1) and 1.66:1 (wave 2) and was the highest for the categories of behavioural/emotional difficulty, communication disorders. There were significant differences between learning need and socio-economic status quantile for all areas except early achievers/advanced learners and physical/medical disability. There was a higher prevalence of behavioural/emotional difficulty, and intellectual disability, in the lower socio-economic status quantiles and a higher prevalence of communication disorders in the mid-to-high socio-economic status quantiles. More children were identified as having an additional learning need in grades 1-3 (5-9 years of age). The children who were perceived as requiring the highest level of teacher support were those with an intellectual disability. CONCLUSIONS: This study provides comparative prevalence data for children with additional learning needs. There was a high prevalence of children typically seen in the caseloads of speech and language therapists, and teachers identified that many of these children required high levels of support within the classroom.


Subject(s)
Communication Disorders/epidemiology , Developmental Disabilities/epidemiology , Learning Disabilities/epidemiology , Adolescent , Age Distribution , Attitude of Health Personnel , Child , Child, Preschool , Communication Disorders/complications , Developmental Disabilities/complications , Education, Special , Female , Humans , Learning Disabilities/complications , Male , New South Wales/epidemiology , Prevalence , Referral and Consultation , Sex Distribution , Socioeconomic Factors , Speech Therapy
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