Sample records for compensatory molecular evolution

  1. The nearly neutral and selection theories of molecular evolution under the fisher geometrical framework: substitution rate, population size, and complexity.

    PubMed

    Razeto-Barry, Pablo; Díaz, Javier; Vásquez, Rodrigo A

    2012-06-01

    The general theories of molecular evolution depend on relatively arbitrary assumptions about the relative distribution and rate of advantageous, deleterious, neutral, and nearly neutral mutations. The Fisher geometrical model (FGM) has been used to make distributions of mutations biologically interpretable. We explored an FGM-based molecular model to represent molecular evolutionary processes typically studied by nearly neutral and selection models, but in which distributions and relative rates of mutations with different selection coefficients are a consequence of biologically interpretable parameters, such as the average size of the phenotypic effect of mutations and the number of traits (complexity) of organisms. A variant of the FGM-based model that we called the static regime (SR) represents evolution as a nearly neutral process in which substitution rates are determined by a dynamic substitution process in which the population's phenotype remains around a suboptimum equilibrium fitness produced by a balance between slightly deleterious and slightly advantageous compensatory substitutions. As in previous nearly neutral models, the SR predicts a negative relationship between molecular evolutionary rate and population size; however, SR does not have the unrealistic properties of previous nearly neutral models such as the narrow window of selection strengths in which they work. In addition, the SR suggests that compensatory mutations cannot explain the high rate of fixations driven by positive selection currently found in DNA sequences, contrary to what has been previously suggested. We also developed a generalization of SR in which the optimum phenotype can change stochastically due to environmental or physiological shifts, which we called the variable regime (VR). VR models evolution as an interplay between adaptive processes and nearly neutral steady-state processes. When strong environmental fluctuations are incorporated, the process becomes a selection model in which evolutionary rate does not depend on population size, but is critically dependent on the complexity of organisms and mutation size. For SR as well as VR we found that key parameters of molecular evolution are linked by biological factors, and we showed that they cannot be fixed independently by arbitrary criteria, as has usually been assumed in previous molecular evolutionary models.

  2. The Nearly Neutral and Selection Theories of Molecular Evolution Under the Fisher Geometrical Framework: Substitution Rate, Population Size, and Complexity

    PubMed Central

    Razeto-Barry, Pablo; Díaz, Javier; Vásquez, Rodrigo A.

    2012-01-01

    The general theories of molecular evolution depend on relatively arbitrary assumptions about the relative distribution and rate of advantageous, deleterious, neutral, and nearly neutral mutations. The Fisher geometrical model (FGM) has been used to make distributions of mutations biologically interpretable. We explored an FGM-based molecular model to represent molecular evolutionary processes typically studied by nearly neutral and selection models, but in which distributions and relative rates of mutations with different selection coefficients are a consequence of biologically interpretable parameters, such as the average size of the phenotypic effect of mutations and the number of traits (complexity) of organisms. A variant of the FGM-based model that we called the static regime (SR) represents evolution as a nearly neutral process in which substitution rates are determined by a dynamic substitution process in which the population’s phenotype remains around a suboptimum equilibrium fitness produced by a balance between slightly deleterious and slightly advantageous compensatory substitutions. As in previous nearly neutral models, the SR predicts a negative relationship between molecular evolutionary rate and population size; however, SR does not have the unrealistic properties of previous nearly neutral models such as the narrow window of selection strengths in which they work. In addition, the SR suggests that compensatory mutations cannot explain the high rate of fixations driven by positive selection currently found in DNA sequences, contrary to what has been previously suggested. We also developed a generalization of SR in which the optimum phenotype can change stochastically due to environmental or physiological shifts, which we called the variable regime (VR). VR models evolution as an interplay between adaptive processes and nearly neutral steady-state processes. When strong environmental fluctuations are incorporated, the process becomes a selection model in which evolutionary rate does not depend on population size, but is critically dependent on the complexity of organisms and mutation size. For SR as well as VR we found that key parameters of molecular evolution are linked by biological factors, and we showed that they cannot be fixed independently by arbitrary criteria, as has usually been assumed in previous molecular evolutionary models. PMID:22426879

  3. Mitochondrial-nuclear interactions and accelerated compensatory evolution: evidence from the primate cytochrome C oxidase complex.

    PubMed

    Osada, Naoki; Akashi, Hiroshi

    2012-01-01

    Accelerated rates of mitochondrial protein evolution have been proposed to reflect Darwinian coadaptation for efficient energy production for mammalian flight and brain activity. However, several features of mammalian mtDNA (absence of recombination, small effective population size, and high mutation rate) promote genome degradation through the accumulation of weakly deleterious mutations. Here, we present evidence for "compensatory" adaptive substitutions in nuclear DNA- (nDNA) encoded mitochondrial proteins to prevent fitness decline in primate mitochondrial protein complexes. We show that high mutation rate and small effective population size, key features of primate mitochondrial genomes, can accelerate compensatory adaptive evolution in nDNA-encoded genes. We combine phylogenetic information and the 3D structure of the cytochrome c oxidase (COX) complex to test for accelerated compensatory changes among interacting sites. Physical interactions among mtDNA- and nDNA-encoded components are critical in COX evolution; amino acids in close physical proximity in the 3D structure show a strong tendency for correlated evolution among lineages. Only nuclear-encoded components of COX show evidence for positive selection and adaptive nDNA-encoded changes tend to follow mtDNA-encoded amino acid changes at nearby sites in the 3D structure. This bias in the temporal order of substitutions supports compensatory weak selection as a major factor in accelerated primate COX evolution.

  4. Plastid-Nuclear Interaction and Accelerated Coevolution in Plastid Ribosomal Genes in Geraniaceae.

    PubMed

    Weng, Mao-Lun; Ruhlman, Tracey A; Jansen, Robert K

    2016-06-27

    Plastids and mitochondria have many protein complexes that include subunits encoded by organelle and nuclear genomes. In animal cells, compensatory evolution between mitochondrial and nuclear-encoded subunits was identified and the high mitochondrial mutation rates were hypothesized to drive compensatory evolution in nuclear genomes. In plant cells, compensatory evolution between plastid and nucleus has rarely been investigated in a phylogenetic framework. To investigate plastid-nuclear coevolution, we focused on plastid ribosomal protein genes that are encoded by plastid and nuclear genomes from 27 Geraniales species. Substitution rates were compared for five sets of genes representing plastid- and nuclear-encoded ribosomal subunit proteins targeted to the cytosol or the plastid as well as nonribosomal protein controls. We found that nonsynonymous substitution rates (dN) and the ratios of nonsynonymous to synonymous substitution rates (ω) were accelerated in both plastid- (CpRP) and nuclear-encoded subunits (NuCpRP) of the plastid ribosome relative to control sequences. Our analyses revealed strong signals of cytonuclear coevolution between plastid- and nuclear-encoded subunits, in which nonsynonymous substitutions in CpRP and NuCpRP tend to occur along the same branches in the Geraniaceae phylogeny. This coevolution pattern cannot be explained by physical interaction between amino acid residues. The forces driving accelerated coevolution varied with cellular compartment of the sequence. Increased ω in CpRP was mainly due to intensified positive selection whereas increased ω in NuCpRP was caused by relaxed purifying selection. In addition, the many indels identified in plastid rRNA genes in Geraniaceae may have contributed to changes in plastid subunits. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  5. Widespread Positive Selection Drives Differentiation of Centromeric Proteins in the Drosophila melanogaster subgroup.

    PubMed

    Beck, Emily A; Llopart, Ana

    2015-11-25

    Rapid evolution of centromeric satellite repeats is thought to cause compensatory amino acid evolution in interacting centromere-associated kinetochore proteins. Cid, a protein that mediates kinetochore/centromere interactions, displays particularly high amino acid turnover. Rapid evolution of both Cid and centromeric satellite repeats led us to hypothesize that the apparent compensatory evolution may extend to interacting partners in the Condensin I complex (i.e., SMC2, SMC4, Cap-H, Cap-D2, and Cap-G) and HP1s. Missense mutations in these proteins often result in improper centromere formation and aberrant chromosome segregation, thus selection for maintained function and coevolution among proteins of the complex is likely strong. Here, we report evidence of rapid evolution and recurrent positive selection in seven centromere-associated proteins in species of the Drosophila melanogaster subgroup, and further postulate that positive selection on these proteins could be a result of centromere drive and compensatory changes, with kinetochore proteins competing for optimal spindle attachment.

  6. Multidimensional adaptive evolution of a feed-forward network and the illusion of compensation

    PubMed Central

    Bullaughey, Kevin

    2016-01-01

    When multiple substitutions affect a trait in opposing ways, they are often assumed to be compensatory, not only with respect to the trait, but also with respect to fitness. This type of compensatory evolution has been suggested to underlie the evolution of protein structures and interactions, RNA secondary structures, and gene regulatory modules and networks. The possibility for compensatory evolution results from epistasis. Yet if epistasis is widespread, then it is also possible that the opposing substitutions are individually adaptive. I term this possibility an adaptive reversal. Although possible for arbitrary phenotype-fitness mappings, it has not yet been investigated whether such epistasis is prevalent in a biologically-realistic setting. I investigate a particular regulatory circuit, the type I coherent feed-forward loop, which is ubiquitous in natural systems and is accurately described by a simple mathematical model. I show that such reversals are common during adaptive evolution, can result solely from the topology of the fitness landscape, and can occur even when adaptation follows a modest environmental change and the network was well adapted to the original environment. The possibility of adaptive reversals warrants a systems perspective when interpreting substitution patterns in gene regulatory networks. PMID:23289561

  7. The evolution of sex: A new hypothesis based on mitochondrial mutational erosion: Mitochondrial mutational erosion in ancestral eukaryotes would favor the evolution of sex, harnessing nuclear recombination to optimize compensatory nuclear coadaptation.

    PubMed

    Havird, Justin C; Hall, Matthew D; Dowling, Damian K

    2015-09-01

    The evolution of sex in eukaryotes represents a paradox, given the "twofold" fitness cost it incurs. We hypothesize that the mutational dynamics of the mitochondrial genome would have favored the evolution of sexual reproduction. Mitochondrial DNA (mtDNA) exhibits a high-mutation rate across most eukaryote taxa, and several lines of evidence suggest that this high rate is an ancestral character. This seems inexplicable given that mtDNA-encoded genes underlie the expression of life's most salient functions, including energy conversion. We propose that negative metabolic effects linked to mitochondrial mutation accumulation would have invoked selection for sexual recombination between divergent host nuclear genomes in early eukaryote lineages. This would provide a mechanism by which recombinant host genotypes could be rapidly shuffled and screened for the presence of compensatory modifiers that offset mtDNA-induced harm. Under this hypothesis, recombination provides the genetic variation necessary for compensatory nuclear coadaptation to keep pace with mitochondrial mutation accumulation. © 2015 WILEY Periodicals, Inc.

  8. Compensatory mechanisms in Parkinson's disease: Circuits adaptations and role in disease modification.

    PubMed

    Blesa, Javier; Trigo-Damas, Inés; Dileone, Michele; Del Rey, Natalia Lopez-Gonzalez; Hernandez, Ledia F; Obeso, José A

    2017-12-01

    The motor features of Parkinson's disease (PD) are well known to manifest only when striatal dopaminergic deficit reaches 60-70%. Thus, PD has a long pre-symptomatic and pre-motor evolution during which compensatory mechanisms take place to delay the clinical onset of disabling manifestations. Classic compensatory mechanisms have been attributed to changes and adjustments in the nigro-striatal system, such as increased neuronal activity in the substantia nigra pars compacta and enhanced dopamine synthesis and release in the striatum. However, it is not so clear currently that such changes occur early enough to account for the pre-symptomatic period. Other possible mechanisms relate to changes in basal ganglia and motor cortical circuits including the cerebellum. However, data from early PD patients are difficult to obtain as most studies have been carried out once the diagnosis and treatments have been established. Likewise, putative compensatory mechanisms taking place throughout disease evolution are nearly impossible to distinguish by themselves. Here, we review the evidence for the role of the best known and other possible compensatory mechanisms in PD. We also discuss the possibility that, although beneficial in practical terms, compensation could also play a deleterious role in disease progression. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Evidence for Compensatory Responses at the Molecular, Biochemical, and Tissue Level in Fathead Minnows Exposed to Steroidogenesis Inhibitors

    EPA Science Inventory

    In order to survive, organisms require a capacity to adapt to a wide variety of biotic and abiotic stressors, including chemicals of both natural and synthetic origin. Recent studies in our laboratory have provided evidence of compensatory responses to endocrine active chemicals...

  10. A molecular description of the evolution of resistance

    NASA Technical Reports Server (NTRS)

    Ordoukhanian, P.; Joyce, G. F.

    1999-01-01

    BACKGROUND: In vitro evolution has been used to obtain nucleic acid molecules with interesting functional properties. The evolution process usually is carried out in a stepwise manner, involving successive rounds of selection, amplification and mutation. Recently, a continuous in vitro evolution system was devised for RNAs that catalyze the ligation of oligonucleotide substrates, allowing the evolution of catalytic function to be studied in real time. RESULTS: Continuous in vitro evolution of an RNA ligase ribozyme was carried out in the presence of a DNA enzyme that was capable of cleaving, and thereby inactivating, the ribozyme. The DNA concentration was increased steadily over 33.5 hours of evolution, reaching a final concentration that would have been sufficient to inactivate the starting population in one second. The evolved population of ribozymes developed resistance to the DNA enzyme, reducing their vulnerability to cleavage by 2000-fold but retaining their own catalytic function. Based on sequencing and kinetic analysis of the ribozymes, two mechanisms are proposed for this resistance. One involves three nucleotide substitutions, together with two compensatory mutations, that alter the site at which the DNA enzyme binds the ribozyme. The other involves enhancement of the ribozyme's ability to bind its own substrate in a way that protects it from cleavage by the DNA enzyme. CONCLUSIONS: The ability to direct the evolution of an enzyme's biochemical properties in response to the behavior of another macromolecule provides insight into the evolution of resistance and may be useful in developing enzymes with novel or enhanced function.

  11. Conservative and compensatory evolution in oxidative phosphorylation complexes of angiosperms with highly divergent rates of mitochondrial genome evolution.

    PubMed

    Havird, Justin C; Whitehill, Nicholas S; Snow, Christopher D; Sloan, Daniel B

    2015-12-01

    Interactions between nuclear and mitochondrial gene products are critical for eukaryotic cell function. Nuclear genes encoding mitochondrial-targeted proteins (N-mt genes) experience elevated rates of evolution, which has often been interpreted as evidence of nuclear compensation in response to elevated mitochondrial mutation rates. However, N-mt genes may be under relaxed functional constraints, which could also explain observed increases in their evolutionary rate. To disentangle these hypotheses, we examined patterns of sequence and structural evolution in nuclear- and mitochondrial-encoded oxidative phosphorylation proteins from species in the angiosperm genus Silene with vastly different mitochondrial mutation rates. We found correlated increases in N-mt gene evolution in species with fast-evolving mitochondrial DNA. Structural modeling revealed an overrepresentation of N-mt substitutions at positions that directly contact mutated residues in mitochondrial-encoded proteins, despite overall patterns of conservative structural evolution. These findings support the hypothesis that selection for compensatory changes in response to mitochondrial mutations contributes to the elevated rate of evolution in N-mt genes. We discuss these results in light of theories implicating mitochondrial mutation rates and mitonuclear coevolution as drivers of speciation and suggest comparative and experimental approaches that could take advantage of heterogeneity in rates of mtDNA evolution across eukaryotes to evaluate such theories. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  12. Pathways to extinction: beyond the error threshold.

    PubMed

    Manrubia, Susanna C; Domingo, Esteban; Lázaro, Ester

    2010-06-27

    Since the introduction of the quasispecies and the error catastrophe concepts for molecular evolution by Eigen and their subsequent application to viral populations, increased mutagenesis has become a common strategy to cause the extinction of viral infectivity. Nevertheless, the high complexity of virus populations has shown that viral extinction can occur through several other pathways apart from crossing an error threshold. Increases in the mutation rate enhance the appearance of defective forms and promote the selection of mechanisms that are able to counteract the accelerated appearance of mutations. Current models of viral evolution take into account more realistic scenarios that consider compensatory and lethal mutations, a highly redundant genotype-to-phenotype map, rough fitness landscapes relating phenotype and fitness, and where phenotype is described as a set of interdependent traits. Further, viral populations cannot be understood without specifying the characteristics of the environment where they evolve and adapt. Altogether, it turns out that the pathways through which viral quasispecies go extinct are multiple and diverse.

  13. Characterizing the roles of changing population size and selection on the evolution of flux control in metabolic pathways.

    PubMed

    Orlenko, Alena; Chi, Peter B; Liberles, David A

    2017-05-25

    Understanding the genotype-phenotype map is fundamental to our understanding of genomes. Genes do not function independently, but rather as part of networks or pathways. In the case of metabolic pathways, flux through the pathway is an important next layer of biological organization up from the individual gene or protein. Flux control in metabolic pathways, reflecting the importance of mutation to individual enzyme genes, may be evolutionarily variable due to the role of mutation-selection-drift balance. The evolutionary stability of rate limiting steps and the patterns of inter-molecular co-evolution were evaluated in a simulated pathway with a system out of equilibrium due to fluctuating selection, population size, or positive directional selection, to contrast with those under stabilizing selection. Depending upon the underlying population genetic regime, fluctuating population size was found to increase the evolutionary stability of rate limiting steps in some scenarios. This result was linked to patterns of local adaptation of the population. Further, during positive directional selection, as with more complex mutational scenarios, an increase in the observation of inter-molecular co-evolution was observed. Differences in patterns of evolution when systems are in and out of equilibrium, including during positive directional selection may lead to predictable differences in observed patterns for divergent evolutionary scenarios. In particular, this result might be harnessed to detect differences between compensatory processes and directional processes at the pathway level based upon evolutionary observations in individual proteins. Detecting functional shifts in pathways reflects an important milestone in predicting when changes in genotypes result in changes in phenotypes.

  14. Twenty Months of Evolution Following Sympathectomy on Patients with Palmar Hyperhidrosis: Sympathectomy at the T3 Level is Better than at the T2 Level

    PubMed Central

    Yazbek, Guilherme; Wolosker, Nelson; Kauffman, Paulo; de Campos, José Ribas Milanez; Puech-Leão, Pedro; Jatene, Fábio Biscegli

    2009-01-01

    OBJECTIVE To compare two surgical techniques (denervation levels) for sympathectomy using video-assisted thoracoscopy to treat palmar hyperhidrosis in the long-term. METHODS From May 2003 to June 2006, 60 patients with palmar hyperhidrosis were prospectively randomized for video-assisted thoracoscopic sympathectomy at the T2 or T3 ganglion level. They were followed for a mean of 20 months and were evaluated regarding their degree of improvement of palmar hyperhidrosis, incidence and severity of compensatory hyperhidrosis and its evolution over time, and quality of life. RESULTS Fifty-nine cases presented resolution of the palmar hyperhidrosis. One case of therapeutic failure occurred in the T3 group. Most of the patients presented an improvement in palmar hyperhidrosis, without any difference between the groups. Twenty months later, all patients in both groups presented some degree of compensatory hyperhidrosis but with less severity in the T3 group (p = 0.007). Compensatory hyperhidrosis developed in most patients during the first month after the operation, with incidence and severity that remained stable over time. An improvement in quality of life was seen starting from the first postoperative evaluation but without any difference between the groups. This improvement was maintained until the end of the follow-up. CONCLUSION Both techniques were effective for treating palmar hyperhidrosis. The most frequent complication was compensatory hyperhidrosis, which presented stable incidence and severity over the study period. Sympathectomy at the T3 level presented compensatory hyperhidrosis with less severity. Nevertheless, the improvement in quality of life was similar between the groups. PMID:19690657

  15. Membrane Repair: Mechanisms and Pathophysiology

    PubMed Central

    Cooper, Sandra T.; McNeil, Paul L.

    2015-01-01

    Eukaryotic cells have been confronted throughout their evolution with potentially lethal plasma membrane injuries, including those caused by osmotic stress, by infection from bacterial toxins and parasites, and by mechanical and ischemic stress. The wounded cell can survive if a rapid repair response is mounted that restores boundary integrity. Calcium has been identified as the key trigger to activate an effective membrane repair response that utilizes exocytosis and endocytosis to repair a membrane tear, or remove a membrane pore. We here review what is known about the cellular and molecular mechanisms of membrane repair, with particular emphasis on the relevance of repair as it relates to disease pathologies. Collective evidence reveals membrane repair employs primitive yet robust molecular machinery, such as vesicle fusion and contractile rings, processes evolutionarily honed for simplicity and success. Yet to be fully understood is whether core membrane repair machinery exists in all cells, or whether evolutionary adaptation has resulted in multiple compensatory repair pathways that specialize in different tissues and cells within our body. PMID:26336031

  16. A pivot mutation impedes reverse evolution across an adaptive landscape for drug resistance in Plasmodium vivax.

    PubMed

    Ogbunugafor, C Brandon; Hartl, Daniel

    2016-01-25

    The study of reverse evolution from resistant to susceptible phenotypes can reveal constraints on biological evolution, a topic for which evolutionary theory has relatively few general principles. The public health catastrophe of antimicrobial resistance in malaria has brought these constraints on evolution into a practical realm, with one proposed solution: withdrawing anti-malarial medication use in high resistance settings, built on the assumption that reverse evolution occurs readily enough that populations of pathogens may revert to their susceptible states. While past studies have suggested limits to reverse evolution, there have been few attempts to properly dissect its mechanistic constraints. Growth rates were determined from empirical data on the growth and resistance from a set of combinatorially complete set of mutants of a resistance protein (dihydrofolate reductase) in Plasmodium vivax, to construct reverse evolution trajectories. The fitness effects of individual mutations were calculated as a function of drug environment, revealing the magnitude of epistatic interactions between mutations and genetic backgrounds. Evolution across the landscape was simulated in two settings: starting from the population fixed for the quadruple mutant, and from a polymorphic population evenly distributed between double mutants. A single mutation of large effect (S117N) serves as a pivot point for evolution to high resistance regions of the landscape. Through epistatic interactions with other mutations, this pivot creates an epistatic ratchet against reverse evolution towards the wild type ancestor, even in environments where the wild type is the most fit of all genotypes. This pivot mutation underlies the directional bias in evolution across the landscape, where evolution towards the ancestor is precluded across all examined drug concentrations from various starting points in the landscape. The presence of pivot mutations can dictate dynamics of evolution across adaptive landscape through epistatic interactions within a protein, leaving a population trapped on local fitness peaks in an adaptive landscape, unable to locate ancestral genotypes. This irreversibility suggests that the structure of an adaptive landscape for a resistance protein should be understood before considering resistance management strategies. This proposed mechanism for constraints on reverse evolution corroborates evidence from the field indicating that phenotypic reversal often occurs via compensatory mutation at sites independent of those associated with the forward evolution of resistance. Because of this, molecular methods that identify resistance patterns via single SNPs in resistance-associated markers might be missing signals for resistance and compensatory mutation throughout the genome. In these settings, whole genome sequencing efforts should be used to identify resistance patterns, and will likely reveal a more complicated genomic signature for resistance and susceptibility, especially in settings where anti-malarial medications have been used intermittently. Lastly, the findings suggest that, given their role in dictating the dynamics of evolution across the landscape, pivot mutations might serve as future targets for therapy.

  17. Global gene expression in muscle from fasted/refed trout reveals up-regulation of genes promoting myofibre hypertrophy but not myofibre production.

    PubMed

    Rescan, Pierre-Yves; Le Cam, Aurelie; Rallière, Cécile; Montfort, Jérôme

    2017-06-07

    Compensatory growth is a phase of rapid growth, greater than the growth rate of control animals, that occurs after a period of growth-stunting conditions. Fish show a capacity for compensatory growth after alleviation of dietary restriction, but the underlying cellular mechanisms are unknown. To learn more about the contribution of genes regulating hypertrophy (an increase in muscle fibre size) and hyperplasia (the generation of new muscle fibres) in the compensatory muscle growth response in fish, we used high-density microarray analysis to investigate the global gene expression in muscle of trout during a fasting-refeeding schedule and in muscle of control-fed trout displaying normal growth. The compensatory muscle growth signature, as defined by genes up-regulated in muscles of refed trout compared with control-fed trout, showed enrichment in functional categories related to protein biosynthesis and maturation, such as RNA processing, ribonucleoprotein complex biogenesis, ribosome biogenesis, translation and protein folding. This signature was also enriched in chromatin-remodelling factors of the protein arginine N-methyl transferase family. Unexpectedly, functional categories related to cell division and DNA replication were not inferred from the molecular signature of compensatory muscle growth, and this signature contained virtually none of the genes previously reported to be up-regulated in hyperplastic growth zones of the late trout embryo myotome and to potentially be involved in production of new myofibres, notably genes encoding myogenic regulatory factors, transmembrane receptors essential for myoblast fusion or myofibrillar proteins predominant in nascent myofibres. Genes promoting myofibre growth, but not myofibre formation, were up-regulated in muscles of refed trout compared with continually fed trout. This suggests that a compensatory muscle growth response, resulting from the stimulation of hypertrophy but not the stimulation of hyperplasia, occurs in trout after refeeding. The generation of a large set of genes up-regulated in muscle of refed trout may yield insights into the molecular and cellular mechanisms controlling skeletal muscle mass in teleost and serve as a useful list of potential molecular markers of muscle growth in fish.

  18. Plastid–Nuclear Interaction and Accelerated Coevolution in Plastid Ribosomal Genes in Geraniaceae

    PubMed Central

    Weng, Mao-Lun; Ruhlman, Tracey A.; Jansen, Robert K.

    2016-01-01

    Plastids and mitochondria have many protein complexes that include subunits encoded by organelle and nuclear genomes. In animal cells, compensatory evolution between mitochondrial and nuclear-encoded subunits was identified and the high mitochondrial mutation rates were hypothesized to drive compensatory evolution in nuclear genomes. In plant cells, compensatory evolution between plastid and nucleus has rarely been investigated in a phylogenetic framework. To investigate plastid–nuclear coevolution, we focused on plastid ribosomal protein genes that are encoded by plastid and nuclear genomes from 27 Geraniales species. Substitution rates were compared for five sets of genes representing plastid- and nuclear-encoded ribosomal subunit proteins targeted to the cytosol or the plastid as well as nonribosomal protein controls. We found that nonsynonymous substitution rates (dN) and the ratios of nonsynonymous to synonymous substitution rates (ω) were accelerated in both plastid- (CpRP) and nuclear-encoded subunits (NuCpRP) of the plastid ribosome relative to control sequences. Our analyses revealed strong signals of cytonuclear coevolution between plastid- and nuclear-encoded subunits, in which nonsynonymous substitutions in CpRP and NuCpRP tend to occur along the same branches in the Geraniaceae phylogeny. This coevolution pattern cannot be explained by physical interaction between amino acid residues. The forces driving accelerated coevolution varied with cellular compartment of the sequence. Increased ω in CpRP was mainly due to intensified positive selection whereas increased ω in NuCpRP was caused by relaxed purifying selection. In addition, the many indels identified in plastid rRNA genes in Geraniaceae may have contributed to changes in plastid subunits. PMID:27190001

  19. The genomic basis of adaptation to the fitness cost of rifampicin resistance in Pseudomonas aeruginosa

    PubMed Central

    Toll-Riera, Macarena; Heilbron, Karl

    2016-01-01

    Antibiotic resistance carries a fitness cost that must be overcome in order for resistance to persist over the long term. Compensatory mutations that recover the functional defects associated with resistance mutations have been argued to play a key role in overcoming the cost of resistance, but compensatory mutations are expected to be rare relative to generally beneficial mutations that increase fitness, irrespective of antibiotic resistance. Given this asymmetry, population genetics theory predicts that populations should adapt by compensatory mutations when the cost of resistance is large, whereas generally beneficial mutations should drive adaptation when the cost of resistance is small. We tested this prediction by determining the genomic mechanisms underpinning adaptation to antibiotic-free conditions in populations of the pathogenic bacterium Pseudomonas aeruginosa that carry costly antibiotic resistance mutations. Whole-genome sequencing revealed that populations founded by high-cost rifampicin-resistant mutants adapted via compensatory mutations in three genes of the RNA polymerase core enzyme, whereas populations founded by low-cost mutants adapted by generally beneficial mutations, predominantly in the quorum-sensing transcriptional regulator gene lasR. Even though the importance of compensatory evolution in maintaining resistance has been widely recognized, our study shows that the roles of general adaptation in maintaining resistance should not be underestimated and highlights the need to understand how selection at other sites in the genome influences the dynamics of resistance alleles in clinical settings. PMID:26763710

  20. Effects of ornamentation and phylogeny on the evolution of wing shape in stalk-eyed flies (Diopsidae).

    PubMed

    Husak, J F; Ribak, G; Baker, R H; Rivera, G; Wilkinson, G S; Swallow, J G

    2013-06-01

    Exaggerated male ornaments are predicted to be costly to their bearers, but these negative effects may be offset by the correlated evolution of compensatory traits. However, when locomotor systems, such as wings in flying species, evolve to decrease such costs, it remains unclear whether functional changes across related species are achieved via the same morphological route or via alternate changes that have similar function. We conducted a comparative analysis of wing shape in relation to eye-stalk elongation across 24 species of stalk-eyed flies, using geometric morphometrics to determine how species with increased eye span, a sexually selected trait, have modified wing morphology as a compensatory mechanism. Using traditional and phylogenetically informed multivariate analyses of shape in combination with phenotypic trajectory analysis, we found a strong phylogenetic signal in wing shape. However, dimorphic species possessed shifted wing veins with the result of lengthening and narrowing wings compared to monomorphic species. Dimorphic species also had changes that seem unrelated to wing size, but instead may govern wing flexion. Nevertheless, the lack of a uniform, compensatory pattern suggests that stalk-eyed flies used alternative modifications in wing structure to increase wing area and aspect ratio, thus taking divergent morphological routes to compensate for exaggerated eye stalks. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  1. Molecular evolution of the mitochondrial 12S rRNA in Ungulata (mammalia).

    PubMed

    Douzery, E; Catzeflis, F M

    1995-11-01

    The complete 12S rRNA gene has been sequenced in 4 Ungulata (hoofed eutherians) and 1 marsupial and compared to 38 available mammalian sequences in order to investigate the molecular evolution of the mitochondrial small-subunit ribosomal RNA molecule. Ungulata were represented by one artiodactyl (the collared peccary, Tayassu tajacu, suborder Suiformes), two perissodactyls (the Grevy's zebra, Equus grevyi, suborder Hippomorpha; the white rhinoceros, Ceratotherium simum, suborder Ceratomorpha), and one hyracoid (the tree hyrax, Dendrohyrax dorsalis). The fifth species was a marsupial, the eastern gray kangaroo (Macropus giganteus). Several transition/transversion biases characterized the pattern of changes between mammalian 12S rRNA molecules. A bias toward transitions was found among 12S rRNA sequences of Ungulata, illustrating the general bias exhibited by ribosomal and protein-encoding genes of the mitochondrial genome. The derivation of a mammalian 12S rRNA secondary structure model from the comparison of 43 eutherian and marsupial sequences evidenced a pronounced bias against transversions in stems. Moreover, transversional compensatory changes were rare events within double-stranded regions of the ribosomal RNA. Evolutionary characteristics of the 12S rRNA were compared with those of the nuclear 18S and 28S rRNAs. From a phylogenetic point of view, transitions, transversions and indels in stems as well as transversional and indels events in loops gave congruent results for comparisons within orders. Some compensatory changes in double-stranded regions and some indels in single-stranded regions also constituted diagnostic events. The 12S rRNA molecule confirmed the monophyly of infraorder Pecora and order Cetacea and demonstrated the monophyly of the suborder Ruminantia was not supported and the branching pattern between Cetacea and the artiodacytyl suborders Ruminantia and Suiformes was not established. The monophyly of the order Perissodactyla was evidenced, but the relationships between Artiodactyla, Cetacea, and Perissodactyla remained unresolved. Nevertheless, we found no support for a Perissodactyla + Hyracoidea clade, neither with distance approach, nor with parsimony reconstruction. The 12S rRNA was useful to solve intraordinal relationships among Ungulata, but it seemed to harbor too few informative positions to decipher the bushlike radiation of some Ungulata orders, an event which has most probably occurred in a short span of time between 55 and 70 MYA.

  2. Dissection of expression-quantitative trait locus and allele specificity using a haploid/diploid plant system - insights into compensatory evolution of transcriptional regulation within populations.

    PubMed

    Verta, Jukka-Pekka; Landry, Christian R; MacKay, John

    2016-07-01

    Regulation of gene expression plays a central role in translating genotypic variation into phenotypic variation. Dissection of the genetic basis of expression variation is key to understanding how expression regulation evolves. Such analyses remain challenging in contexts where organisms are outbreeding, highly heterozygous and long-lived such as in the case of conifer trees. We developed an RNA sequencing (RNA-seq)-based approach for both expression-quantitative trait locus (eQTL) mapping and the detection of cis-acting (allele-specific) vs trans-acting (non-allele-specific) eQTLs. This method can be potentially applied to many conifers. We used haploid and diploid meiotic seed tissues of a single self-fertilized white spruce (Picea glauca) individual to dissect eQTLs according to linkage and allele specificity. The genetic architecture of local eQTLs linked to the expressed genes was particularly complex, consisting of cis-acting, trans-acting and, surprisingly, compensatory cis-trans effects. These compensatory effects influence expression in opposite directions and are neutral when combined in homozygotes. Nearly half of local eQTLs were under compensation, indicating that close linkage between compensatory cis-trans factors is common in spruce. Compensated genes were overrepresented in developmental and cell organization functions. Our haploid-diploid eQTL analysis in spruce revealed that compensatory cis-trans eQTLs segregate within populations and evolve in close genetic linkage. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  3. Evolution of weed resistance to herbicides: What have we learned after 70 years?

    USDA-ARS?s Scientific Manuscript database

    As Darwin understood more than 150 years ago, sufficiently strong and constant selection pressure on a population of organisms over an adequate time period inevitably leads to compensatory genetic changes in that population. Synthetic pesticides have been the "perfect storm" for such a process, prov...

  4. Hsp83 loss suppresses proteasomal activity resulting in an upregulation of caspase-dependent compensatory autophagy.

    PubMed

    Choutka, Courtney; DeVorkin, Lindsay; Go, Nancy Erro; Hou, Ying-Chen Claire; Moradian, Annie; Morin, Gregg B; Gorski, Sharon M

    2017-09-02

    The 2 main degradative pathways that contribute to proteostasis are the ubiquitin-proteasome system and autophagy but how they are molecularly coordinated is not well understood. Here, we demonstrate an essential role for an effector caspase in the activation of compensatory autophagy when proteasomal activity is compromised. Functional loss of Hsp83, the Drosophila ortholog of human HSP90 (heat shock protein 90), resulted in reduced proteasomal activity and elevated levels of the effector caspase Dcp-1. Surprisingly, genetic analyses showed that the caspase was not required for cell death in this context, but instead was essential for the ensuing compensatory autophagy, female fertility, and organism viability. The zymogen pro-Dcp-1 was found to interact with Hsp83 and undergo proteasomal regulation in an Hsp83-dependent manner. Our work not only reveals unappreciated roles for Hsp83 in proteasomal activity and regulation of Dcp-1, but identifies an effector caspase as a key regulatory factor for sustaining adaptation to cell stress in vivo.

  5. Vestibular Restoration and Adaptation in Vestibular Neuritis and Ramsay Hunt Syndrome With Vertigo.

    PubMed

    Martin-Sanz, Eduardo; Rueda, Almudena; Esteban-Sanchez, Jonathan; Yanes, Joaquin; Rey-Martinez, Jorge; Sanz-Fernandez, Ricardo

    2017-08-01

    To evaluate vestibular restoration and the evolution of the compensatory saccades in acute severe inflammatory vestibular nerve paralysis, including vestibular neuritis and Ramsay Hunt syndrome with vertigo. Prospective. Tertiary referral center. Vestibular neuritis (n = 18) and Ramsay Hunt syndrome patients with vertigo (n = 13) were enrolled. After treatment with oral corticosteroids, patients were followed up for 6 months. Functional recovery of the facial nerve was scored according to the House-Brackman grading system. Caloric and video head impulse tests were performed in every patient at the time of enrolment. Subsequently, successive video head impulse test (vHIT) exploration was performed at the 1, 3, and 6-month follow-up. Eighteen patients with vestibular neuritis and 13 with Ramsay Hunt syndrome and associated vertigo were included. Vestibular function was significantly worse in patients with Ramsay Hunt syndrome than in those with vestibular neuritis. Similar compensatory saccades velocity and latency values were observed in both groups, in both the caloric and initial vHIT tests. Successive vHIT results showed a significantly higher vestibulo-ocular reflex gain recovery in vestibular neuritis patients than in Ramsay Hunt syndrome patients. A significantly faster reduction in the latency, velocity, and organization of the compensatory saccades was observed in neuritis than in Ramsay Hunt syndrome patients. In addition to the recovery of the vestibulo-ocular reflex, the reduction of latency, velocity and the organization of compensatory saccades play a role in vestibular compensation.

  6. Neuroprotection and neurorestoration as experimental therapeutics for Parkinson's disease.

    PubMed

    Francardo, Veronica; Schmitz, Yvonne; Sulzer, David; Cenci, M Angela

    2017-12-01

    Disease-modifying treatments remain an unmet medical need in Parkinson's disease (PD). Such treatments can be operationally defined as interventions that slow down the clinical evolution to advanced disease milestones. A treatment may achieve this outcome by either inhibiting primary neurodegenerative events ("neuroprotection") or boosting compensatory and regenerative mechanisms in the brain ("neurorestoration"). Here we review experimental paradigms that are currently used to assess the neuroprotective and neurorestorative potential of candidate treatments in animal models of PD. We review some key molecular mediators of neuroprotection and neurorestoration in the nigrostriatal dopamine pathway that are likely to exert beneficial effects on multiple neural systems affected in PD. We further review past and current strategies to therapeutically stimulate these mediators, and discuss the preclinical evidence that exercise training can have neuroprotective and neurorestorative effects. A future translational task will be to combine behavioral and pharmacological interventions to exploit endogenous mechanisms of neuroprotection and neurorestoration for therapeutic purposes. This type of approach is likely to provide benefit to many PD patients, despite the clinical, etiological, and genetic heterogeneity of the disease. Copyright © 2017. Published by Elsevier Inc.

  7. Paleoproterozoic snowball earth: extreme climatic and geochemical global change and its biological consequences

    NASA Technical Reports Server (NTRS)

    Kirschvink, J. L.; Gaidos, E. J.; Bertani, L. E.; Beukes, N. J.; Gutzmer, J.; Maepa, L. N.; Steinberger, R. E.

    2000-01-01

    Geological, geophysical, and geochemical data support a theory that Earth experienced several intervals of intense, global glaciation ("snowball Earth" conditions) during Precambrian time. This snowball model predicts that postglacial, greenhouse-induced warming would lead to the deposition of banded iron formations and cap carbonates. Although global glaciation would have drastically curtailed biological productivity, melting of the oceanic ice would also have induced a cyanobacterial bloom, leading to an oxygen spike in the euphotic zone and to the oxidative precipitation of iron and manganese. A Paleoproterozoic snowball Earth at 2.4 Giga-annum before present (Ga) immediately precedes the Kalahari Manganese Field in southern Africa, suggesting that this rapid and massive change in global climate was responsible for its deposition. As large quantities of O(2) are needed to precipitate this Mn, photosystem II and oxygen radical protection mechanisms must have evolved before 2.4 Ga. This geochemical event may have triggered a compensatory evolutionary branching in the Fe/Mn superoxide dismutase enzyme, providing a Paleoproterozoic calibration point for studies of molecular evolution.

  8. Cellular and molecular responses to increased skeletal muscle loading after irradiation

    NASA Technical Reports Server (NTRS)

    Adams, Gregory R.; Caiozzo, Vincent J.; Haddad, Fadia; Baldwin, Kenneth M.

    2002-01-01

    Irradiation of rat skeletal muscles before increased loading has been shown to prevent compensatory hypertrophy for periods of up to 4 wk, possibly by preventing satellite cells from proliferating and providing new myonuclei. Recent work suggested that stem cell populations exist that might allow irradiated muscles to eventually hypertrophy over time. We report that irradiation essentially prevented hypertrophy in rat muscles subjected to 3 mo of functional overload (OL-Ir). The time course and magnitude of changes in cellular and molecular markers of anabolic and myogenic responses were similar in the OL-Ir and the contralateral nonirradiated, overloaded (OL) muscles for the first 3-7 days. These markers then returned to control levels in OL-Ir muscles while remaining elevated in OL muscles. The number of myonuclei and amount of DNA were increased markedly in OL but not OL-Ir muscles. Thus it appears that stem cells were not added to the irradiated muscles in this time period. These data are consistent with the theory that the addition of new myonuclei may be required for compensatory hypertrophy in the rat.

  9. Reliving the History of Compensatory Education: Policy Choices, Bureaucracy, and the Politicized Role of Science in the Evolution of Head Start

    ERIC Educational Resources Information Center

    Beatty, Barbara; Zigler, Edward

    2012-01-01

    In this article, Edward Zigler, interviewed by Barbara Beatty, talks about a turning point in the history of Head Start that reveals how policy choices, bureaucracy, and science came together when he was told to phase out the program in 1970. New to Washington, Zigler learned that President Richard M. Nixon's domestic policy advisor Daniel Patrick…

  10. High-altitude physiology: lessons from Tibet

    NASA Astrophysics Data System (ADS)

    Wagner, Peter D.; Simonson, Tatum S.; Wei, Guan; Wagner, Harrieth; Wuren, Tanna; Yan, Ma; Qin, Ga; Ge, Rili

    2013-05-01

    Polycythemia is a universal lowlander response to altitude; healthy Andean high-altitude natives also have elevated [Hb]. While this may enhance O2 transport to tissues, studies have shown that acute isovolumic changes in [Hb] do not affect exercise capacity. Many high-altitude Tibetans have evolved sea-level values of [Hb], providing a natural opportunity to study this issue. In 21 young healthy male Tibetans with [Hb] between 15 and 23 g/dl, we measured VO2MAX and O2 transport capacity at 4200m. VO2MAX was higher when [Hb] was lower (P<0.05), enabled by both higher cardiac output and muscle O2 diffusional conductance, but neither ventilation nor the alveolar-arterial PO2 difference (AaPO2) varied with [Hb]. In contrast, Andean high altitude natives remain polycythemic with larger lungs and higher lung diffusing capacity, a smaller exercising AaPO2, and lower ventilation. The challenges now are (1) to understand the different adaptive pathways used by Andeans and Tibetans, and (2) to determine in Tibetans whether, during evolution, reduced [Hb] appeared first, causing compensatory cardiac and muscle adaptations, or if enhanced cardiac function and muscle O2 transport capacity appeared first, permitting secondary reduction in [Hb]. For (2), further research is necessary to determine the basis of enhanced cardiac function and muscle O2 transport, and identify molecular targets of evolution in heart and muscle. Putative mutations can then be timed and compared to appearance of those affecting [Hb].

  11. Evolution of specialization under non-equilibrium population dynamics.

    PubMed

    Nurmi, Tuomas; Parvinen, Kalle

    2013-03-21

    We analyze the evolution of specialization in resource utilization in a mechanistically underpinned discrete-time model using the adaptive dynamics approach. We assume two nutritionally equivalent resources that in the absence of consumers grow sigmoidally towards a resource-specific carrying capacity. The consumers use resources according to the law of mass-action with rates involving trade-off. The resulting discrete-time model for the consumer population has over-compensatory dynamics. We illuminate the way non-equilibrium population dynamics affect the evolutionary dynamics of the resource consumption rates, and show that evolution to the trimorphic coexistence of a generalist and two specialists is possible due to asynchronous non-equilibrium population dynamics of the specialists. In addition, various forms of cyclic evolutionary dynamics are possible. Furthermore, evolutionary suicide may occur even without Allee effects and demographic stochasticity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Vertical control in the Class III compensatory treatment.

    PubMed

    Sobral, Márcio Costa; Habib, Fernando A L; Nascimento, Ana Carla de Souza

    2013-01-01

    Compensatory orthodontic treatment, or simply orthodontic camouflage, consists in an important alternative to orthognathic surgery in the resolution of skeletal discrepancies in adult patients. It is important to point that, to be successfully performed, diagnosis must be detailed, to evaluate, specifically, dental and facial features, as well as the limitations imposed by the magnitude of the discrepancy. The main complaint, patient's treatment expectation, periodontal limits, facial pattern and vertical control are some of the items to be explored in the determination of the viability of a compensatory treatment. Hyperdivergent patients who present with a Class III skeletal discrepancy, associated with a vertical facial pattern, with the presence or tendency to anterior open bite, deserve special attention. In these cases, an efficient strategy of vertical control must be planned and executed. The present article aims at illustrating the evolution of efficient alternatives of vertical control in hiperdivergent patients, from the use, in the recent past, of extraoral appliances on the lower dental arch (J-hook), until nowadays, with the advent of skeletal anchorage. But for patients with a more balanced facial pattern, the conventional mechanics with Class III intermaxillary elastics, associated to an accentuated curve of Spee in the upper arch and a reverse curve of Spee in the lower arch, and vertical elastics in the anterior region, continues to be an excellent alternative, if there is extreme collaboration in using the elastics.

  13. Clinically Applicable Inhibitors Impacting Genome Stability.

    PubMed

    Prakash, Anu; Garcia-Moreno, Juan F; Brown, James A L; Bourke, Emer

    2018-05-13

    Advances in technology have facilitated the molecular profiling (genomic and transcriptomic) of tumours, and has led to improved stratification of patients and the individualisation of treatment regimes. To fully realize the potential of truly personalised treatment options, we need targeted therapies that precisely disrupt the compensatory pathways identified by profiling which allow tumours to survive or gain resistance to treatments. Here, we discuss recent advances in novel therapies that impact the genome (chromosomes and chromatin), pathways targeted and the stage of the pathways targeted. The current state of research will be discussed, with a focus on compounds that have advanced into trials (clinical and pre-clinical). We will discuss inhibitors of specific DNA damage responses and other genome stability pathways, including those in development, which are likely to synergistically combine with current therapeutic options. Tumour profiling data, combined with the knowledge of new treatments that affect the regulation of essential tumour signalling pathways, is revealing fundamental insights into cancer progression and resistance mechanisms. This is the forefront of the next evolution of advanced oncology medicine that will ultimately lead to improved survival and may, one day, result in many cancers becoming chronic conditions, rather than fatal diseases.

  14. Global Analysis of the Evolution and Mechanism of Echinocandin Resistance in Candida glabrata

    PubMed Central

    Singh-Babak, Sheena D.; Babak, Tomas; Diezmann, Stephanie; Hill, Jessica A.; Xie, Jinglin Lucy; Chen, Ying-Lien; Poutanen, Susan M.; Rennie, Robert P.; Heitman, Joseph; Cowen, Leah E.

    2012-01-01

    The evolution of drug resistance has a profound impact on human health. Candida glabrata is a leading human fungal pathogen that can rapidly evolve resistance to echinocandins, which target cell wall biosynthesis and are front-line therapeutics for Candida infections. Here, we provide the first global analysis of mutations accompanying the evolution of fungal drug resistance in a human host utilizing a series of C. glabrata isolates that evolved echinocandin resistance in a patient treated with the echinocandin caspofungin for recurring bloodstream candidemia. Whole genome sequencing identified a mutation in the drug target, FKS2, accompanying a major resistance increase, and 8 additional non-synonymous mutations. The FKS2-T1987C mutation was sufficient for echinocandin resistance, and associated with a fitness cost that was mitigated with further evolution, observed in vitro and in a murine model of systemic candidemia. A CDC6-A511G(K171E) mutation acquired before FKS2-T1987C(S663P), conferred a small resistance increase. Elevated dosage of CDC55, which acquired a C463T(P155S) mutation after FKS2-T1987C(S663P), ameliorated fitness. To discover strategies to abrogate echinocandin resistance, we focused on the molecular chaperone Hsp90 and downstream effector calcineurin. Genetic or pharmacological compromise of Hsp90 or calcineurin function reduced basal tolerance and resistance. Hsp90 and calcineurin were required for caspofungin-dependent FKS2 induction, providing a mechanism governing echinocandin resistance. A mitochondrial respiration-defective petite mutant in the series revealed that the petite phenotype does not confer echinocandin resistance, but renders strains refractory to synergy between echinocandins and Hsp90 or calcineurin inhibitors. The kidneys of mice infected with the petite mutant were sterile, while those infected with the HSP90-repressible strain had reduced fungal burden. We provide the first global view of mutations accompanying the evolution of fungal drug resistance in a human host, implicate the premier compensatory mutation mitigating the cost of echinocandin resistance, and suggest a new mechanism of echinocandin resistance with broad therapeutic potential. PMID:22615574

  15. RNA structural constraints in the evolution of the influenza A virus genome NP segment

    PubMed Central

    Gultyaev, Alexander P; Tsyganov-Bodounov, Anton; Spronken, Monique IJ; van der Kooij, Sander; Fouchier, Ron AM; Olsthoorn, René CL

    2014-01-01

    Conserved RNA secondary structures were predicted in the nucleoprotein (NP) segment of the influenza A virus genome using comparative sequence and structure analysis. A number of structural elements exhibiting nucleotide covariations were identified over the whole segment length, including protein-coding regions. Calculations of mutual information values at the paired nucleotide positions demonstrate that these structures impose considerable constraints on the virus genome evolution. Functional importance of a pseudoknot structure, predicted in the NP packaging signal region, was confirmed by plaque assays of the mutant viruses with disrupted structure and those with restored folding using compensatory substitutions. Possible functions of the conserved RNA folding patterns in the influenza A virus genome are discussed. PMID:25180940

  16. Altered cortical GABA neurotransmission in schizophrenia: insights into novel therapeutic strategies.

    PubMed

    Stan, Ana D; Lewis, David A

    2012-06-01

    Altered markers of cortical GABA neurotransmission are among the most consistently observed abnormalities in postmortem studies of schizophrenia. The altered markers are particularly evident between the chandelier class of GABA neurons and their synaptic targets, the axon initial segment (AIS) of pyramidal neurons. For example, in the dorsolateral prefrontal cortex of subjects with schizophrenia immunoreactivity for the GABA membrane transporter is decreased in presynaptic chandelier neuron axon terminals, whereas immunoreactivity for the GABAA receptor α2 subunit is increased in postsynaptic AIS. Both of these molecular changes appear to be compensatory responses to a presynaptic deficit in GABA synthesis, and thus could represent targets for novel therapeutic strategies intended to augment the brain's own compensatory mechanisms. Recent findings that GABA inputs from neocortical chandelier neurons can be powerfully excitatory provide new ideas about the role of these neurons in the pathophysiology of cortical dysfunction in schizophrenia, and consequently in the design of pharmacological interventions.

  17. The First Molecular Phylogeny of Strepsiptera (Insecta) Reveals an Early Burst of Molecular Evolution Correlated with the Transition to Endoparasitism

    PubMed Central

    McMahon, Dino P.; Hayward, Alexander; Kathirithamby, Jeyaraney

    2011-01-01

    A comprehensive model of evolution requires an understanding of the relationship between selection at the molecular and phenotypic level. We investigate this in Strepsiptera, an order of endoparasitic insects whose evolutionary biology is poorly studied. We present the first molecular phylogeny of Strepsiptera, and use this as a framework to investigate the association between parasitism and molecular evolution. We find evidence of a significant burst in the rate of molecular evolution in the early history of Strepsiptera. The evolution of morphological traits linked to parasitism is significantly correlated with the pattern in molecular rate. The correlated burst in genotypic-phenotypic evolution precedes the main phase of strepsipteran diversification, which is characterised by the return to a low and even molecular rate, and a period of relative morphological stability. These findings suggest that the transition to endoparasitism led to relaxation of selective constraint in the strepsipteran genome. Our results indicate that a parasitic lifestyle can affect the rate of molecular evolution, although other causal life-history traits correlated with parasitism may also play an important role. PMID:21738621

  18. In vivo assessment of aortic aneurysm wall integrity using elastin-specific molecular magnetic resonance imaging.

    PubMed

    Botnar, René M; Wiethoff, Andrea J; Ebersberger, Ullrich; Lacerda, Sara; Blume, Ulrike; Warley, Alice; Jansen, Christian H P; Onthank, David C; Cesati, Richard R; Razavi, Reza; Marber, Michael S; Hamm, Bernd; Schaeffter, Tobias; Robinson, Simon P; Makowski, Marcus R

    2014-07-01

    The incidence of abdominal aortic aneurysms (AAAs) has increased during the last decades. However, there is still controversy about the management of medium-sized AAAs. Therefore, novel biomarkers, besides aneurysmal diameter, are needed to assess aortic wall integrity and risk of rupture. Elastin is the key protein for maintaining aortic wall tensile strength and stability. The progressive breakdown of structural proteins, in particular, medial elastin, is responsible for the inability of the aortic wall to withstand intraluminal hemodynamic forces. Here, we evaluate the usefulness of elastin-specific molecular MRI for the in vivo characterization of AAAs. To induce AAAs, ApoE(-/-) mice were infused with angiotensin-II. An elastin-specific magnetic resonance molecular imaging agent (ESMA) was administered after 1, 2, 3, and 4 weeks of angiotensin-II infusion to assess elastin composition of the aorta (n=8 per group). The high signal provided by ESMA allowed for imaging with high spatial resolution, resulting in an accurate assessment of ruptured elastic laminae and the compensatory expression of elastic fibers. In vivo contrast-to-noise ratios and R1-relaxation rates after ESMA administration were in good agreement with ex vivo histomorphometry (Elastica van Gieson stain) and gadolinium concentrations determined by inductively coupled plasma mass spectroscopy. Electron microscopy confirmed colocalization of ESMA with elastic fibers. Changes in elastin content could be readily delineated and quantified at different stages of AAAs by elastin-specific molecular magnetic resonance imaging. ESMA-MRI offers potential for the noninvasive detection of the aortic rupture site prior to dilation of the aorta and the subsequent in vivo monitoring of compensatory repair processes during the progression of AAAs. © 2014 American Heart Association, Inc.

  19. The family structure of the Mucorales: a synoptic revision based on comprehensive multigene-genealogies.

    PubMed

    Hoffmann, K; Pawłowska, J; Walther, G; Wrzosek, M; de Hoog, G S; Benny, G L; Kirk, P M; Voigt, K

    2013-06-01

    The Mucorales (Mucoromycotina) are one of the most ancient groups of fungi comprising ubiquitous, mostly saprotrophic organisms. The first comprehensive molecular studies 11 yr ago revealed the traditional classification scheme, mainly based on morphology, as highly artificial. Since then only single clades have been investigated in detail but a robust classification of the higher levels based on DNA data has not been published yet. Therefore we provide a classification based on a phylogenetic analysis of four molecular markers including the large and the small subunit of the ribosomal DNA, the partial actin gene and the partial gene for the translation elongation factor 1-alpha. The dataset comprises 201 isolates in 103 species and represents about one half of the currently accepted species in this order. Previous family concepts are reviewed and the family structure inferred from the multilocus phylogeny is introduced and discussed. Main differences between the current classification and preceding concepts affects the existing families Lichtheimiaceae and Cunninghamellaceae, as well as the genera Backusella and Lentamyces which recently obtained the status of families along with the Rhizopodaceae comprising Rhizopus, Sporodiniella and Syzygites. Compensatory base change analyses in the Lichtheimiaceae confirmed the lower level classification of Lichtheimia and Rhizomucor while genera such as Circinella or Syncephalastrum completely lacked compensatory base changes.

  20. 5 CFR 550.1405 - Crediting compensatory time off.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1405 Crediting compensatory time off. (a) Upon a... employee is entitled to credit for compensatory time off for travel under the conditions specified in this... employee's request for credit of compensatory time off for travel may be denied if the request is not filed...

  1. 5 CFR 550.1405 - Crediting compensatory time off.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1405 Crediting compensatory time off. (a) Upon a... employee is entitled to credit for compensatory time off for travel under the conditions specified in this... employee's request for credit of compensatory time off for travel may be denied if the request is not filed...

  2. 5 CFR 550.1405 - Crediting compensatory time off.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1405 Crediting compensatory time off. (a) Upon a... employee is entitled to credit for compensatory time off for travel under the conditions specified in this... employee's request for credit of compensatory time off for travel may be denied if the request is not filed...

  3. 5 CFR 550.1405 - Crediting compensatory time off.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1405 Crediting compensatory time off. (a) Upon a... employee is entitled to credit for compensatory time off for travel under the conditions specified in this... employee's request for credit of compensatory time off for travel may be denied if the request is not filed...

  4. 5 CFR 550.1405 - Crediting compensatory time off.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1405 Crediting compensatory time off. (a) Upon a... employee is entitled to credit for compensatory time off for travel under the conditions specified in this... employee's request for credit of compensatory time off for travel may be denied if the request is not filed...

  5. Predicting the onset of inappropriate compensatory behaviors in undergraduate college women.

    PubMed

    Jones, Michelle D; Crowther, Janis H

    2013-01-01

    The present study examined various factors from the interactive and sociocultural models of bulimia nervosa as predictors of the onset of compensatory behaviors. Participants (n=237) completed a series of questionnaires assessing dietary restraint, body dissatisfaction, negative affect, binge eating, perfectionism, and self-esteem at two time points one year apart. Women who did not engage in compensatory behaviors at time one but did engage in compensatory behaviors at time two (n=21) were compared to women who engaged in compensatory behaviors at both time points (n=28) and women who did not engage in compensatory behaviors at either time point (n=188). Body dissatisfaction and perfectionism at time one significantly predicted women who began using compensatory behaviors compared to women who did not engage in compensatory behaviors at either time point. Women who experienced an onset of compensatory behaviors also reported significantly greater body dissatisfaction at time 1 than women who engaged in compensatory behaviors for the duration of the study. Implications and limitations of these findings are discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Molecular evolution and the latitudinal biodiversity gradient.

    PubMed

    Dowle, E J; Morgan-Richards, M; Trewick, S A

    2013-06-01

    Species density is higher in the tropics (low latitude) than in temperate regions (high latitude) resulting in a latitudinal biodiversity gradient (LBG). The LBG must be generated by differential rates of speciation and/or extinction and/or immigration among regions, but the role of each of these processes is still unclear. Recent studies examining differences in rates of molecular evolution have inferred a direct link between rate of molecular evolution and rate of speciation, and postulated these as important drivers of the LBG. Here we review the molecular genetic evidence and examine the factors that might be responsible for differences in rates of molecular evolution. Critical to this is the directionality of the relationship between speciation rates and rates of molecular evolution.

  7. Workshop on Molecular Evolution

    NASA Technical Reports Server (NTRS)

    Cummings, Michael P.

    2004-01-01

    Molecular evolution has become the nexus of many areas of biological research. It both brings together and enriches such areas as biochemistry, molecular biology, microbiology, population genetics, systematics, developmental biology, genomics, bioinformatics, in vitro evolution, and molecular ecology. The Workshop provides an important contribution to these fields in that it promotes interdisciplinary research and interaction, and thus provides a glue that sticks together disparate fields. Due to the wide range of fields addressed by the study of molecular evolution, it is difficult to offer a comprehensive course in a university setting. It is rare for a single institution to maintain expertise in all necessary areas. In contrast, the Workshop is uniquely able to provide necessary breadth and depth by utilizing a large number of faculty with appropriate expertise. Furthermore, the flexible nature of the Workshop allows for rapid adaptation to changes in the dynamic field of molecular evolution. For example, the 2003 Workshop included recently emergent research areas of molecular evolution of development and genomics.

  8. Molecular Evolution in Historical Perspective.

    PubMed

    Suárez-Díaz, Edna

    2016-12-01

    In the 1960s, advances in protein chemistry and molecular genetics provided new means for the study of biological evolution. Amino acid sequencing, nucleic acid hybridization, zone gel electrophoresis, and immunochemistry were some of the experimental techniques that brought about new perspectives to the study of the patterns and mechanisms of evolution. New concepts, such as the molecular evolutionary clock, and the discovery of unexpected molecular phenomena, like the presence of repetitive sequences in eukaryotic genomes, eventually led to the realization that evolution might occur at a different pace at the organismic and the molecular levels, and according to different mechanisms. These developments sparked important debates between defendants of the molecular and organismic approaches. The most vocal confrontations focused on the relation between primates and humans, and the neutral theory of molecular evolution. By the 1980s and 1990s, the construction of large protein and DNA sequences databases, and the development of computer-based statistical tools, facilitated the coming together of molecular and evolutionary biology. Although in its contemporary form the field of molecular evolution can be traced back to the last five decades, the field has deep roots in twentieth century experimental life sciences. For historians of science, the origins and consolidation of molecular evolution provide a privileged field for the study of scientific debates, the relation between technological advances and scientific knowledge, and the connection between science and broader social concerns.

  9. Instant Update: Considering the Molecular Mechanisms of Mutation & Natural Selection

    ERIC Educational Resources Information Center

    Hubler, Tina; Adams, Patti; Scammell, Jonathan

    2015-01-01

    The molecular basis of evolution is an important concept to understand but one that students and teachers often find challenging. This article provides training and guidance for teachers on how to present molecular evolution concepts so that students will associate molecular changes with the evolution of form and function in organisms. Included…

  10. Information Propagation in Developmental Enhancers

    NASA Astrophysics Data System (ADS)

    Jena, Siddhartha; Levine, Michael

    Rather than encoding information about protein sequence, certain lengths of noncoding DNA, called enhancers, interact with protein machinery such as transcription factors to precisely regulate gene expression. Enhancers have been studied extensively in the fruit fly Drosophila melanogaster, where they regulate the expression of developmental genes that establish the blueprint of the adult fly. It has been suggested that enhancer sequences possess a specific but unknown syntax with regards to the placement and strength of transcription factor binding sites. Moreover, studies in divergent fly species have shown that compensatory evolution allows for maintenance of enhancer functionality despite considerable variation in primary DNA sequence. Here, the possible role of enhancers as signal processing modules is studied as a way of explaining these two findings. We first demonstrate how this framework can be used to explain the fine-tuned spatiotemporal dynamics of gene expression. We then explore the evolutionary pressure on enhancer sequences and the resulting emergence of enhancers that are linked by compensatory mutations. This study provides a possible mechanism for the function of multiple enhancers linked to a single gene.

  11. Environmental Epigenetics and a Unified Theory of the Molecular Aspects of Evolution: A Neo-Lamarckian Concept that Facilitates Neo-Darwinian Evolution.

    PubMed

    Skinner, Michael K

    2015-04-26

    Environment has a critical role in the natural selection process for Darwinian evolution. The primary molecular component currently considered for neo-Darwinian evolution involves genetic alterations and random mutations that generate the phenotypic variation required for natural selection to act. The vast majority of environmental factors cannot directly alter DNA sequence. Epigenetic mechanisms directly regulate genetic processes and can be dramatically altered by environmental factors. Therefore, environmental epigenetics provides a molecular mechanism to directly alter phenotypic variation generationally. Lamarck proposed in 1802 the concept that environment can directly alter phenotype in a heritable manner. Environmental epigenetics and epigenetic transgenerational inheritance provide molecular mechanisms for this process. Therefore, environment can on a molecular level influence the phenotypic variation directly. The ability of environmental epigenetics to alter phenotypic and genotypic variation directly can significantly impact natural selection. Neo-Lamarckian concept can facilitate neo-Darwinian evolution. A unified theory of evolution is presented to describe the integration of environmental epigenetic and genetic aspects of evolution. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  12. 5 CFR 550.1403 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Compensatory Time Off for Travel § 550.1403 Definitions. In this subpart: Accrued compensatory time off means... pay limitations. Compensatory time off means compensatory time off for travel that is credited under... of determining whether travel time is compensable for the purpose of determining overtime pay...

  13. 5 CFR 550.1403 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) Compensatory Time Off for Travel § 550.1403 Definitions. In this subpart: Accrued compensatory time off means... pay limitations. Compensatory time off means compensatory time off for travel that is credited under... of determining whether travel time is compensable for the purpose of determining overtime pay...

  14. 5 CFR 550.1403 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) Compensatory Time Off for Travel § 550.1403 Definitions. In this subpart: Accrued compensatory time off means... pay limitations. Compensatory time off means compensatory time off for travel that is credited under... of determining whether travel time is compensable for the purpose of determining overtime pay...

  15. 5 CFR 550.1403 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) Compensatory Time Off for Travel § 550.1403 Definitions. In this subpart: Accrued compensatory time off means... pay limitations. Compensatory time off means compensatory time off for travel that is credited under... of determining whether travel time is compensable for the purpose of determining overtime pay...

  16. 5 CFR 550.1403 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) Compensatory Time Off for Travel § 550.1403 Definitions. In this subpart: Accrued compensatory time off means... pay limitations. Compensatory time off means compensatory time off for travel that is credited under... of determining whether travel time is compensable for the purpose of determining overtime pay...

  17. A Primer on the Genetics of Comorbid Eating Disorders and Substance Use Disorders.

    PubMed

    Munn-Chernoff, Melissa A; Baker, Jessica H

    2016-03-01

    Eating disorders (EDs) and substance use disorders (SUDs) frequently co-occur; however, the reasons for this are unclear. We review the current literature on genetic risk for EDs and SUDs, as well as preliminary findings exploring whether these classes of disorders have overlapping genetic risk. Overall, genetic factors contribute to individual differences in liability to multiple EDs and SUDs. Although initial family studies concluded that no shared familial (which includes genetic) risk between EDs and SUDs exists, twin studies suggest a moderate proportion of shared variance is attributable to overlapping genetic factors, particularly for those EDs characterized by binge eating and/or inappropriate compensatory behaviours. No adoption or molecular genetic studies have examined shared genetic risk between these classes of disorders. Research investigating binge eating and inappropriate compensatory behaviours using emerging statistical genetic methods, as well as examining gene-environment interplay, will provide important clues into the aetiology of comorbid EDs and SUDs. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.

  18. The Development of a Novel Measure to Assess Motives for Compensatory Eating in Response to Exercise: The CEMQ.

    PubMed

    Moshier, Samantha J; Landau, Aaron J; Hearon, Bridget A; Stein, Aliza T; Greathouse, Lee; Smits, Jasper A J; Otto, Michael W

    2016-01-01

    Compensatory eating in response to exercise may be an obstacle to achieving weight-loss and fitness goals. In this study we develop and conduct a preliminary examination of the psychometric properties of the Compensatory Eating Motives Questionnaire (CEMQ), a self-report questionnaire of motives for compensatory eating. Development and testing of the CEMQ was conducted in two student samples. Of respondents, 75% reported engaging in compensatory eating. Factor analysis yielded factors representing three domains of motives for compensatory eating: Eating for Reward, Eating for Recovery, and Eating for Relief. Internal consistency of the factors was adequate, and the factor structure was replicated. Correlations between the CEMQ subscales and trait questionnaires supported hypotheses for convergent and divergent validity. These results encourage further investigation of compensatory eating as a potential obstacle to weight loss, and support the continued assessment of the CEMQ as a tool to measure three conceptually distinct motives for compensatory eating.

  19. OnabotulinumtoxinA therapy for compensatory hyperhidrosis.

    PubMed

    Adefusika, Jessica A; Brewer, Jerry D

    2013-09-01

    Compensatory hyperhidrosis due to the treatment for focal primary hyperhidrosis can be devastating and life-altering. The purpose of this paper is to discuss use of the iodine starch test and dilute botulinum toxin to decrease compensatory hyperhidrosis over large surface areas. A large area of the trunk affected by compensatory hyperhidrosis was treated with dilute botulinum toxin therapy using a starch iodine test for localization. The patient had exceptional results with his compensatory truncal sweating returning to normal and remaining stable for multiple months. Treating compensatory hyperhidrosis of large surface areas with dilute botulinum toxin therapy is effective and safe. © 2013 Wiley Periodicals, Inc.

  20. Intergenotypic replacement of lyssavirus matrix proteins demonstrates the role of lyssavirus M proteins in intracellular virus accumulation.

    PubMed

    Finke, Stefan; Granzow, Harald; Hurst, Jose; Pollin, Reiko; Mettenleiter, Thomas C

    2010-02-01

    Lyssavirus assembly depends on the matrix protein (M). We compared lyssavirus M proteins from different genotypes for their ability to support assembly and egress of genotype 1 rabies virus (RABV). Transcomplementation of M-deficient RABV with M from European bat lyssavirus (EBLV) types 1 and 2 reduced the release of infectious virus. Stable introduction of the heterogenotypic M proteins into RABV led to chimeric viruses with reduced virus release and intracellular accumulation of virus genomes. Although the chimeras indicated genotype-specific evolution of M, rapid selection of a compensatory mutant suggested conserved mechanisms of lyssavirus assembly and the requirement for only few adaptive mutations to fit the heterogenotypic M to a RABV backbone. Whereas the compensatory mutant replicated to similar infectious titers as RABV M-expressing virus, ultrastructural analysis revealed that both nonadapted EBLV M chimeras and the compensatory mutant differed from RABV M expressing viruses in the lack of intracellular viruslike structures that are enveloped and accumulate in cisterna of the degranulated and dilated rough endoplasmic reticulum compartment. Moreover, all viruses were able to bud at the plasma membrane. Since the lack of the intracellular viruslike structures correlated with the type of M protein but not with the efficiency of virus release, we hypothesize that the M proteins of EBLV-1 and RABV differ in their target membranes for virus assembly. Although the biological function of intracellular assembly and accumulation of viruslike structures in the endoplasmic reticulum remain unclear, the observed differences could contribute to diverse host tropism or pathogenicity.

  1. 29 CFR 553.26 - Cash overtime payments.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...)-Compensatory Time and Compensatory Time Off § 553.26 Cash overtime payments. (a) Overtime compensation due under section 7 may be paid in cash at the employer's option, in lieu of providing compensatory time off... from freely substituting cash, in whole or part, for compensatory time off; and overtime payment in...

  2. 29 CFR 553.26 - Cash overtime payments.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...)-Compensatory Time and Compensatory Time Off § 553.26 Cash overtime payments. (a) Overtime compensation due under section 7 may be paid in cash at the employer's option, in lieu of providing compensatory time off... from freely substituting cash, in whole or part, for compensatory time off; and overtime payment in...

  3. Enzyme Efficiency but Not Thermostability Drives Cefotaxime Resistance Evolution in TEM-1 β-Lactamase.

    PubMed

    Knies, Jennifer L; Cai, Fei; Weinreich, Daniel M

    2017-05-01

    A leading intellectual challenge in evolutionary genetics is to identify the specific phenotypes that drive adaptation. Enzymes offer a particularly promising opportunity to pursue this question, because many enzymes' contributions to organismal fitness depend on a comparatively small number of experimentally accessible properties. Moreover, on first principles the demands of enzyme thermostability stand in opposition to the demands of catalytic activity. This observation, coupled with the fact that enzymes are only marginally thermostable, motivates the widely held hypothesis that mutations conferring functional improvement require compensatory mutations to restore thermostability. Here, we explicitly test this hypothesis for the first time, using four missense mutations in TEM-1 β-lactamase that jointly increase cefotaxime Minimum Inhibitory Concentration (MIC) ∼1500-fold. First, we report enzymatic efficiency (kcat/KM) and thermostability (Tm, and thence ΔG of folding) for all combinations of these mutations. Next, we fit a quantitative model that predicts MIC as a function of kcat/KM and ΔG. While kcat/KM explains ∼54% of the variance in cefotaxime MIC (∼92% after log transformation), ΔG does not improve explanatory power of the model. We also find that cefotaxime MIC rises more slowly in kcat/KM than predicted. Several explanations for these discrepancies are suggested. Finally, we demonstrate substantial sign epistasis in MIC and kcat/KM, and antagonistic pleiotropy between phenotypes, in spite of near numerical additivity in the system. Thus constraints on selectively accessible trajectories, as well as limitations in our ability to explain such constraints in terms of underlying mechanisms are observed in a comparatively "well-behaved" system. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  4. Mistakes and Molecular Evolution.

    ERIC Educational Resources Information Center

    Trevors, J. T.

    1998-01-01

    Examines the role mistakes play in the molecular evolution of bacteria. Discusses the interacting physical, chemical, and biological factors that cause changes in DNA and play a role in prokaryotic evolution. (DDR)

  5. 5 CFR 550.1406 - Use of accrued compensatory time off.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1406 Use of accrued compensatory time off. (a) An employee must request permission from his or her supervisor to schedule the use of his... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Use of accrued compensatory time off. 550...

  6. 5 CFR 550.1406 - Use of accrued compensatory time off.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1406 Use of accrued compensatory time off. (a) An employee must request permission from his or her supervisor to schedule the use of his... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Use of accrued compensatory time off. 550...

  7. 5 CFR 550.1406 - Use of accrued compensatory time off.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1406 Use of accrued compensatory time off. (a) An employee must request permission from his or her supervisor to schedule the use of his... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Use of accrued compensatory time off. 550...

  8. 5 CFR 550.1408 - Prohibition against payment for unused compensatory time off.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... compensatory time off. 550.1408 Section 550.1408 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1408 Prohibition against payment for unused compensatory time off. As provided by 5 U.S.C. 5550b(b), an individual may not...

  9. 5 CFR 550.1407 - Forfeiture of unused compensatory time off.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1407 Forfeiture of unused..., may extend the time limit for using such compensatory time off for travel for up to an additional 26... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Forfeiture of unused compensatory time...

  10. 5 CFR 550.1407 - Forfeiture of unused compensatory time off.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1407 Forfeiture of unused..., may extend the time limit for using such compensatory time off for travel for up to an additional 26... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Forfeiture of unused compensatory time...

  11. 5 CFR 550.1406 - Use of accrued compensatory time off.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1406 Use of accrued compensatory time off. (a) An employee must request permission from his or her supervisor to schedule the use of his... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Use of accrued compensatory time off. 550...

  12. 5 CFR 550.1408 - Prohibition against payment for unused compensatory time off.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... compensatory time off. 550.1408 Section 550.1408 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1408 Prohibition against payment for unused compensatory time off. As provided by 5 U.S.C. 5550b(b), an individual may not...

  13. 5 CFR 550.1408 - Prohibition against payment for unused compensatory time off.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... compensatory time off. 550.1408 Section 550.1408 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1408 Prohibition against payment for unused compensatory time off. As provided by 5 U.S.C. 5550b(b), an individual may not...

  14. 5 CFR 550.1407 - Forfeiture of unused compensatory time off.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1407 Forfeiture of unused..., may extend the time limit for using such compensatory time off for travel for up to an additional 26... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Forfeiture of unused compensatory time...

  15. 5 CFR 550.1408 - Prohibition against payment for unused compensatory time off.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... compensatory time off. 550.1408 Section 550.1408 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1408 Prohibition against payment for unused compensatory time off. As provided by 5 U.S.C. 5550b(b), an individual may not...

  16. 5 CFR 550.1407 - Forfeiture of unused compensatory time off.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1407 Forfeiture of unused..., may extend the time limit for using such compensatory time off for travel for up to an additional 26... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Forfeiture of unused compensatory time...

  17. 5 CFR 550.1408 - Prohibition against payment for unused compensatory time off.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... compensatory time off. 550.1408 Section 550.1408 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1408 Prohibition against payment for unused compensatory time off. As provided by 5 U.S.C. 5550b(b), an individual may not...

  18. 5 CFR 550.1407 - Forfeiture of unused compensatory time off.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1407 Forfeiture of unused..., may extend the time limit for using such compensatory time off for travel for up to an additional 26... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Forfeiture of unused compensatory time...

  19. 5 CFR 550.1406 - Use of accrued compensatory time off.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1406 Use of accrued compensatory time off. (a) An employee must request permission from his or her supervisor to schedule the use of his... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Use of accrued compensatory time off. 550...

  20. Computer-assisted kinematic evaluation of induced compensatory movements resembling lameness in horses trotting on a treadmill.

    PubMed

    Kelmer, Gal; Keegan, Kevin G; Kramer, Joanne; Wilson, David A; Pai, Frank P; Singh, Prableen

    2005-04-01

    To characterize compensatory movements of the head and pelvis that resemble lameness in horses. 17 adult horses. Kinematic evaluations were performed while horses trotted on a treadmill before and after shoe-induced lameness. Lameness was quantified and the affected limb determined by algorithms that measured asymmetry in vertical movement of the head and pelvis. Induced primary lameness and compensatory movements resembling lameness were assessed by the Friedman test. Association between induced lameness and compensatory movements was examined by regression analysis. Compensatory movements resembling lameness in the ipsilateral forelimb were seen with induced lameness of a hind limb. There was less downward and less upward head movement during and after the stance phase of the ipsilateral forelimb. Doubling the severity of lameness in the hind limb increased severity of the compensatory movements in the ipsilateral forelimb by 50%. Compensatory movements resembling lameness of the hind limb were seen after induced lameness in a forelimb. There was less upward movement of the pelvis after the stance phase of the contralateral hind limb and, to a lesser extent, less downward movement of the pelvis during the stance phase of the ipsilateral hind limb. Doubling the severity of lameness in the forelimb increased compensatory movements of the contralateral hind limb by 5%. Induced lameness in a hind limb causes prominent compensatory movements resembling lameness in the ipsilateral forelimb. Induced lameness in a forelimb causes slight compensatory movements resembling lameness in the ipsilateral and contralateral hind limbs.

  1. Mechanisms of oocyte development in European sea bass (Dicentrarchus labrax L.): investigations via application of unilateral ovariectomy.

    PubMed

    García-López, Ángel; Sánchez-Amaya, María I; Tyler, Charles R; Prat, Francisco

    2011-08-01

    Unilateral ovariectomy (ULO) was performed in European sea bass (Dicentrarchus labrax L.) during late pre-vitellogenesis/early vitellogenesis. Plasma steroid levels and the expression of a suite of potential oogenesis-relevant genes in the ovary, brain, and pituitary were evaluated with the aim of understanding their involvement in the compensatory oocyte development occurring within the remaining ovarian lobe. After 69 days of surgery the remaining ovarian lobe in ULO fish was gravimetrically equivalent to an intact-paired ovary of sham operated, control fish. This compensatory ovarian growth was based on an increased number of early perinucleolar oocytes and mid-late stage vitellogenic follicles without an apparent recruitment of primary oocytes into the secondary growth phase. Plasma steroid levels were similar in ULO and control females at all time points analyzed, suggesting an increased steroid production of the remaining ovarian lobe in hemi-castrated females. Results of the gene expression survey conducted indicate that the signaling pathways mediated by Fsh and Gnrh1 constitute the central axes orchestrating the observed ovarian compensatory growth. In addition, steroid receptors, Star protein, Igfs, and members of the transforming growth factor beta superfamily including anti-Mullerian hormone and bone morphogenetic protein 4 were identified as potentially relevant players within this process, although their specific actions and interactions remain to be established. Our results demonstrate that ULO provides an excellent in vivo model for elucidating the interconnected endocrine and molecular mechanisms controlling oocyte development in European sea bass.

  2. Molecular and Proteomic Analysis of Levofloxacin and Metronidazole Resistant Helicobacter pylori.

    PubMed

    Hanafi, Aimi; Lee, Woon Ching; Loke, Mun Fai; Teh, Xinsheng; Shaari, Ain; Dinarvand, Mojdeh; Lehours, Philippe; Mégraud, Francis; Leow, Alex Hwong Ruey; Vadivelu, Jamuna; Goh, Khean Lee

    2016-01-01

    Antibiotic resistance in bacteria incurs fitness cost, but compensatory mechanisms may ameliorate the cost and sustain the resistance even under antibiotics-free conditions. The aim of this study was to determine compensatory mechanisms of antibiotic resistance in H. pylori . Five strains of levofloxacin-sensitive H. pylori were induced in vitro to develop resistance. In addition, four pairs of metronidazole-sensitive and -resistant H. pylori strains were isolated from patients carrying dual H. pylori populations that consist of both sensitive and resistant phenotypes. Growth rate, virulence and biofilm-forming ability of the sensitive and resistant strains were compared to determine effects of compensatory response. Proteome profiles of paired sensitive and resistant strains were analyzed by liquid chromatography/mass spectrophotometry (LC/MS). Although there were no significant differences in growth rate between sensitive and resistant pairs, bacterial virulence (in terms of abilities to induce apoptosis and form biofilm) differs from pair to pair. These findings demonstrate the complex and strain-specific phenotypic changes in compensation for antibiotics resistance. Compensation for in vitro induced levofloxacin resistance involving mutations of gyrA and gyrB was functionally random. Furthermore, higher protein translation and non-functional protein degradation capabilities in naturally-occuring dual population metronidazole sensitive-resistant strains may be a possible alternative mechanism underlying resistance to metronidazole without mutations in rdxA and frxA . This may explain the lack of mutations in target genes in ~10% of metronidazole resistant strains.

  3. α-Synuclein transgenic mice reveal compensatory increases in Parkinson's disease-associated proteins DJ-1 and parkin and have enhanced α-synuclein and PINK1 levels after rotenone treatment.

    PubMed

    George, Sonia; Mok, Su San; Nurjono, Milawaty; Ayton, Scott; Finkelstein, David I; Masters, Colin L; Li, Qiao-Xin; Culvenor, Janetta G

    2010-10-01

    Parkinson's disease (PD) is a severe neurodegenerative disorder characterised by loss of dopaminergic neurons of the substantia nigra. The pathological hallmarks are cytoplasmic inclusions termed Lewy bodies consisting primarily of aggregated alpha-synuclein (alphaSN). Different lines of transgenic mice have been developed to model PD but have failed to recapitulate the hallmarks of this disease. Since treatment of rodents with the pesticide rotenone can reproduce nigrostriatal cell loss and other features of PD, we aimed to test chronic oral administration of rotenone to transgenic mice over-expressing human alphaSN with the A53T mutation. Initial assessment of this transgenic line for compensatory molecular changes indicated decreased brain beta-synuclein expression and significantly increased levels of the PD-associated oxidative stress response protein, DJ-1, and the E3 ubiquitin ligase enzyme, Parkin. Rotenone treatment of 30 mg/kg for 25 doses over a 35-day period was tolerated in the transgenic mice and resulted in decreased spontaneous locomotor movement and increased cytoplasmic alphaSN expression. The mitochondrial Parkinson's-associated PTEN-induced kinase 1 protein levels were also increased in transgenic mouse brain after rotenone treatment; there was no change in brain dopamine levels or nigrostriatal cell loss. These hA53T alphaSN transgenic mice provide a useful model for presymptomatic Parkinson's features and are valuable for study of associated compensatory changes in early Parkinson's disease stages.

  4. Molecular and Proteomic Analysis of Levofloxacin and Metronidazole Resistant Helicobacter pylori

    PubMed Central

    Hanafi, Aimi; Lee, Woon Ching; Loke, Mun Fai; Teh, Xinsheng; Shaari, Ain; Dinarvand, Mojdeh; Lehours, Philippe; Mégraud, Francis; Leow, Alex Hwong Ruey; Vadivelu, Jamuna; Goh, Khean Lee

    2016-01-01

    Antibiotic resistance in bacteria incurs fitness cost, but compensatory mechanisms may ameliorate the cost and sustain the resistance even under antibiotics-free conditions. The aim of this study was to determine compensatory mechanisms of antibiotic resistance in H. pylori. Five strains of levofloxacin-sensitive H. pylori were induced in vitro to develop resistance. In addition, four pairs of metronidazole-sensitive and -resistant H. pylori strains were isolated from patients carrying dual H. pylori populations that consist of both sensitive and resistant phenotypes. Growth rate, virulence and biofilm-forming ability of the sensitive and resistant strains were compared to determine effects of compensatory response. Proteome profiles of paired sensitive and resistant strains were analyzed by liquid chromatography/mass spectrophotometry (LC/MS). Although there were no significant differences in growth rate between sensitive and resistant pairs, bacterial virulence (in terms of abilities to induce apoptosis and form biofilm) differs from pair to pair. These findings demonstrate the complex and strain-specific phenotypic changes in compensation for antibiotics resistance. Compensation for in vitro induced levofloxacin resistance involving mutations of gyrA and gyrB was functionally random. Furthermore, higher protein translation and non-functional protein degradation capabilities in naturally-occuring dual population metronidazole sensitive-resistant strains may be a possible alternative mechanism underlying resistance to metronidazole without mutations in rdxA and frxA. This may explain the lack of mutations in target genes in ~10% of metronidazole resistant strains. PMID:28018334

  5. 5 CFR 551.531 - Compensatory time off.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... paragraph (g) of this section. (e) Compensatory time off to an employee's credit as of May 14, 2007 must be... compensation under 5 U.S.C. chapter 81. (g) The dollar value of compensatory time off when it is liquidated is... head of an agency (or designee) may grant compensatory time off from an employee's tour of duty instead...

  6. 5 CFR 551.531 - Compensatory time off.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... paragraph (g) of this section. (e) Compensatory time off to an employee's credit as of May 14, 2007 must be... compensation under 5 U.S.C. chapter 81. (g) The dollar value of compensatory time off when it is liquidated is... head of an agency (or designee) may grant compensatory time off from an employee's tour of duty instead...

  7. Increase in viability due to the accumulation of X chromosome mutations in Drosophila melanogaster males.

    PubMed

    Woodruff, Ronny C; Balinski, Michael A

    2018-05-09

    To increase our understanding of the role of new X-chromosome mutations in adaptive evolution, single-X Drosophila melanogaster males were mated with attached-X chromosome females, allowing the male X chromosome to accumulate mutations over 28 generations. Contrary to our hypothesis that male viability would decrease over time, due to the accumulation and expression of X-linked recessive deleterious mutations in hemizygous males, viability significantly increased. This increase may be attributed to germinal selection and to new X-linked beneficial or compensatory mutations, possibly supporting the faster-X hypothesis.

  8. Experiments on the role of deleterious mutations as stepping stones in adaptive evolution

    PubMed Central

    Covert, Arthur W.; Lenski, Richard E.; Wilke, Claus O.; Ofria, Charles

    2013-01-01

    Many evolutionary studies assume that deleterious mutations necessarily impede adaptive evolution. However, a later mutation that is conditionally beneficial may interact with a deleterious predecessor before it is eliminated, thereby providing access to adaptations that might otherwise be inaccessible. It is unknown whether such sign-epistatic recoveries are inconsequential events or an important factor in evolution, owing to the difficulty of monitoring the effects and fates of all mutations during experiments with biological organisms. Here, we used digital organisms to compare the extent of adaptive evolution in populations when deleterious mutations were disallowed with control populations in which such mutations were allowed. Significantly higher fitness levels were achieved over the long term in the control populations because some of the deleterious mutations served as stepping stones across otherwise impassable fitness valleys. As a consequence, initially deleterious mutations facilitated the evolution of complex, beneficial functions. We also examined the effects of disallowing neutral mutations, of varying the mutation rate, and of sexual recombination. Populations evolving without neutral mutations were able to leverage deleterious and compensatory mutation pairs to overcome, at least partially, the absence of neutral mutations. Substantially raising or lowering the mutation rate reduced or eliminated the long-term benefit of deleterious mutations, but introducing recombination did not. Our work demonstrates that deleterious mutations can play an important role in adaptive evolution under at least some conditions. PMID:23918358

  9. Experiments on the role of deleterious mutations as stepping stones in adaptive evolution.

    PubMed

    Covert, Arthur W; Lenski, Richard E; Wilke, Claus O; Ofria, Charles

    2013-08-20

    Many evolutionary studies assume that deleterious mutations necessarily impede adaptive evolution. However, a later mutation that is conditionally beneficial may interact with a deleterious predecessor before it is eliminated, thereby providing access to adaptations that might otherwise be inaccessible. It is unknown whether such sign-epistatic recoveries are inconsequential events or an important factor in evolution, owing to the difficulty of monitoring the effects and fates of all mutations during experiments with biological organisms. Here, we used digital organisms to compare the extent of adaptive evolution in populations when deleterious mutations were disallowed with control populations in which such mutations were allowed. Significantly higher fitness levels were achieved over the long term in the control populations because some of the deleterious mutations served as stepping stones across otherwise impassable fitness valleys. As a consequence, initially deleterious mutations facilitated the evolution of complex, beneficial functions. We also examined the effects of disallowing neutral mutations, of varying the mutation rate, and of sexual recombination. Populations evolving without neutral mutations were able to leverage deleterious and compensatory mutation pairs to overcome, at least partially, the absence of neutral mutations. Substantially raising or lowering the mutation rate reduced or eliminated the long-term benefit of deleterious mutations, but introducing recombination did not. Our work demonstrates that deleterious mutations can play an important role in adaptive evolution under at least some conditions.

  10. 29 CFR 553.25 - Conditions for use of compensatory time (“reasonable period”, “unduly disrupt”).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... OF STATE AND LOCAL GOVERNMENTS General Section 7(o)-Compensatory Time and Compensatory Time Off § 553... good faith expect to be able to grant within a reasonable period of his or her making a request for use of such time. (c) Reasonable period. (1) Whether a request to use compensatory time has been granted...

  11. White Book on Physical and Rehabilitation Medicine (PRM) in Europe. Chapter 6. Knowledge and skills of PRM physicians.

    PubMed

    2018-04-01

    In the context of the White Book of Physical and Rehabilitation Medicine (PRM) in Europe, this paper deals with the fundamentals of PRM from a physiological perspective, looking at the human mechanisms both physical and behavioral which are at the base of PRM physicians' work. After a discussion on the development and evolution of PRM that leads to its unique and specific approach, the mechanisms considered include: - repairing processes (and potential of recovery evaluation): repairing processes are mainly related to the quantity and natural history of diseases and impairments, while potential of recovery is also linked to the individual and environmental factors; PRM physicians work on impairments to favor healing or recovery, and propose rehabilitation if there is a potential of recovery: this is related to the prognostic role of PRM physicians; - learning processes: PRM is the specialty of teaching new physical ways and behavioral approaches to make patients participate at best through improvement of impairments and modification of activities; in this perspective, during repair and rehabilitation processes, PRM physicians and the rehabilitation team are teachers of new motor and behavioral strategies; - compensatory processes (adaptation/habilitation/rehabilitation): PRM physicians teach patients how to adapt to the new (acquired) health condition using compensatory mechanisms based on other body structures/functions, behavioral changes and/or assistive devices (or technical aids) (prosthesis and orthosis); during growth PRM physicians aim at allowing a complete (and compensatory) development of the intact function, not to be impaired by the original disease; compensatory processes are related to activities; - management skills: PRM physicians are managers of people and resources; they manage patients and their caregivers, to teach and allow them to reach the best possible participation, also focusing on maintenance; they lead the team, with the aim to make it function at best for the sake of the patient; finally, they manage resource allocation for the functioning of patients and team; - communication skills: PRM physicians need to develop very good communication skills, so to teach, inform and educate patients and their caregivers: this will allow the proper behavioural changes and also the correct physical compensations.

  12. Identifying compensatory movement patterns in the upper extremity using a wearable sensor system.

    PubMed

    Ranganathan, Rajiv; Wang, Rui; Dong, Bo; Biswas, Subir

    2017-11-30

    Movement impairments such as those due to stroke often result in the nervous system adopting atypical movements to compensate for movement deficits. Monitoring these compensatory patterns is critical for improving functional outcomes during rehabilitation. The purpose of this study was to test the feasibility and validity of a wearable sensor system for detecting compensatory trunk kinematics during activities of daily living. Participants with no history of neurological impairments performed reaching and manipulation tasks with their upper extremity, and their movements were recorded by a wearable sensor system and validated using a motion capture system. Compensatory movements of the trunk were induced using a brace that limited range of motion at the elbow. Our results showed that the elbow brace elicited compensatory movements of the trunk during reaching tasks but not manipulation tasks, and that a wearable sensor system with two sensors could reliably classify compensatory movements (~90% accuracy). These results show the potential of the wearable system to assess and monitor compensatory movements outside of a lab setting.

  13. Molecular evolution: concepts and the origin of disciplines.

    PubMed

    Suárez-Díaz, Edna

    2009-03-01

    This paper focuses on the consolidation of Molecular Evolution, a field originating in the 1960s at the interface of molecular biology, biochemistry, evolutionary biology, biophysics and studies on the origin of life and exobiology. The claim is made that Molecular Evolution became a discipline by integrating different sorts of scientific traditions: experimental, theoretical and comparative. The author critically incorporates Timothy Lenoir's treatment of disciplines (1997), as well as ideas developed by Stephen Toulmin (1962) on the same subject. On their account disciplines are spaces where the social and epistemic dimensions of science are deeply and complexly interwoven. However, a more detailed account of discipline formation and the dynamics of an emerging disciplinary field is lacking in their analysis. The present essay suggests focusing on the role of scientific concepts in the double configuration of disciplines: the social/political and the epistemic order. In the case of Molecular Evolution the concepts of molecular clock and informational molecules played a central role, both in differentiating molecular from classical evolutionists, and in promoting communication between the different sorts of traditions integrated in Molecular Evolution. The paper finishes with a reflection on the historicity of disciplines, and the historicity of our concepts of disciplines.

  14. Genetic interaction networks: better understand to better predict

    PubMed Central

    Boucher, Benjamin; Jenna, Sarah

    2013-01-01

    A genetic interaction (GI) between two genes generally indicates that the phenotype of a double mutant differs from what is expected from each individual mutant. In the last decade, genome scale studies of quantitative GIs were completed using mainly synthetic genetic array technology and RNA interference in yeast and Caenorhabditis elegans. These studies raised questions regarding the functional interpretation of GIs, the relationship of genetic and molecular interaction networks, the usefulness of GI networks to infer gene function and co-functionality, the evolutionary conservation of GI, etc. While GIs have been used for decades to dissect signaling pathways in genetic models, their functional interpretations are still not trivial. The existence of a GI between two genes does not necessarily imply that these two genes code for interacting proteins or that the two genes are even expressed in the same cell. In fact, a GI only implies that the two genes share a functional relationship. These two genes may be involved in the same biological process or pathway; or they may also be involved in compensatory pathways with unrelated apparent function. Considering the powerful opportunity to better understand gene function, genetic relationship, robustness and evolution, provided by a genome-wide mapping of GIs, several in silico approaches have been employed to predict GIs in unicellular and multicellular organisms. Most of these methods used weighted data integration. In this article, we will review the later knowledge acquired on GI networks in metazoans by looking more closely into their relationship with pathways, biological processes and molecular complexes but also into their modularity and organization. We will also review the different in silico methods developed to predict GIs and will discuss how the knowledge acquired on GI networks can be used to design predictive tools with higher performances. PMID:24381582

  15. Function of circle of Willis

    PubMed Central

    Vrselja, Zvonimir; Brkic, Hrvoje; Mrdenovic, Stefan; Radic, Radivoje; Curic, Goran

    2014-01-01

    Nearly 400 years ago, Thomas Willis described the arterial ring at the base of the brain (the circle of Willis, CW) and recognized it as a compensatory system in the case of arterial occlusion. This theory is still accepted. We present several arguments that via negativa should discard the compensatory theory. (1) Current theory is anthropocentric; it ignores other species and their analog structures. (2) Arterial pathologies are diseases of old age, appearing after gene propagation. (3) According to the current theory, evolution has foresight. (4) Its commonness among animals indicates that it is probably a convergent evolutionary structure. (5) It was observed that communicating arteries are too small for effective blood flow, and (6) missing or hypoplastic in the majority of the population. We infer that CW, under physiologic conditions, serves as a passive pressure dissipating system; without considerable blood flow, pressure is transferred from the high to low pressure end, the latter being another arterial component of CW. Pressure gradient exists because pulse wave and blood flow arrive into the skull through different cerebral arteries asynchronously, due to arterial tree asymmetry. Therefore, CW and its communicating arteries protect cerebral artery and blood–brain barrier from hemodynamic stress. PMID:24473483

  16. Camelid genomes reveal evolution and adaptation to desert environments.

    PubMed

    Wu, Huiguang; Guang, Xuanmin; Al-Fageeh, Mohamed B; Cao, Junwei; Pan, Shengkai; Zhou, Huanmin; Zhang, Li; Abutarboush, Mohammed H; Xing, Yanping; Xie, Zhiyuan; Alshanqeeti, Ali S; Zhang, Yanru; Yao, Qiulin; Al-Shomrani, Badr M; Zhang, Dong; Li, Jiang; Manee, Manee M; Yang, Zili; Yang, Linfeng; Liu, Yiyi; Zhang, Jilin; Altammami, Musaad A; Wang, Shenyuan; Yu, Lili; Zhang, Wenbin; Liu, Sanyang; Ba, La; Liu, Chunxia; Yang, Xukui; Meng, Fanhua; Wang, Shaowei; Li, Lu; Li, Erli; Li, Xueqiong; Wu, Kaifeng; Zhang, Shu; Wang, Junyi; Yin, Ye; Yang, Huanming; Al-Swailem, Abdulaziz M; Wang, Jun

    2014-10-21

    Bactrian camel (Camelus bactrianus), dromedary (Camelus dromedarius) and alpaca (Vicugna pacos) are economically important livestock. Although the Bactrian camel and dromedary are large, typically arid-desert-adapted mammals, alpacas are adapted to plateaus. Here we present high-quality genome sequences of these three species. Our analysis reveals the demographic history of these species since the Tortonian Stage of the Miocene and uncovers a striking correlation between large fluctuations in population size and geological time boundaries. Comparative genomic analysis reveals complex features related to desert adaptations, including fat and water metabolism, stress responses to heat, aridity, intense ultraviolet radiation and choking dust. Transcriptomic analysis of Bactrian camels further reveals unique osmoregulation, osmoprotection and compensatory mechanisms for water reservation underpinned by high blood glucose levels. We hypothesize that these physiological mechanisms represent kidney evolutionary adaptations to the desert environment. This study advances our understanding of camelid evolution and the adaptation of camels to arid-desert environments.

  17. Evolution of dosage compensation under sexual selection differs between X and Z chromosomes

    PubMed Central

    Mullon, Charles; Wright, Alison E.; Reuter, Max; Pomiankowski, Andrew; Mank, Judith E.

    2015-01-01

    Complete sex chromosome dosage compensation has more often been observed in XY than ZW species. In this study, using a population genetic model and the chicken transcriptome, we assess whether sexual conflict can account for this difference. Sexual conflict over expression is inevitable when mutation effects are correlated across the sexes, as compensatory mutations in the heterogametic sex lead to hyperexpression in the homogametic sex. Coupled with stronger selection and greater reproductive variance in males, this results in slower and less complete evolution of Z compared with X dosage compensation. Using expression variance as a measure of selection strength, we find that, as predicted by the model, dosage compensation in the chicken is most pronounced in genes that are under strong selection biased towards females. Our study explains the pattern of weak dosage compensation in ZW systems, and suggests that sexual selection plays a major role in shaping sex chromosome dosage compensation. PMID:26212613

  18. Compensatory Mitigation Rule Draft Environmental Assessment

    EPA Pesticide Factsheets

    Draft Compensatory Mitigation Rule intended to promote regulatory efficiency by establishing standards and criteria that would apply to compensatory mitigation required for DA permits issued under Section 404 of the Clean Water Act.

  19. VOR Gain Is Related to Compensatory Saccades in Healthy Older Adults

    PubMed Central

    Anson, Eric R.; Bigelow, Robin T.; Carey, John P.; Xue, Qian-Li; Studenski, Stephanie; Schubert, Michael C.; Agrawal, Yuri

    2016-01-01

    Objective: Vestibulo-ocular reflex (VOR) gain is well-suited for identifying rotational vestibular dysfunction, but may miss partial progressive decline in age-related vestibular function. Since compensatory saccades might provide an alternative method for identifying subtle vestibular decline, we describe the relationship between VOR gain and compensatory saccades in healthy older adults. Methods: Horizontal VOR gain was measured in 243 subjects age 60 and older from the Baltimore Longitudinal Study of Aging using video head impulse testing (HIT). Saccades in each HIT were identified as either “compensatory” or “compensatory back-up,” i.e., same or opposite direction as the VOR response respectively. Saccades were also classified as “covert” (occurring during head movement) and “overt” (occurring after head movement). The relationship between VOR gain and percentage of HITs with saccades, as well as the relationship between VOR gain and saccade latency and amplitude, were evaluated using regression analyses adjusting for age, gender, and race. Results: In adjusted analyses, the percentage of HITs with compensatory saccades increased 4.5% for every 0.1 decrease in VOR gain (p < 0.0001). Overt compensatory saccade amplitude decreased 0.6° (p < 0.005) and latency increased 90 ms (p < 0.001) for every 0.1 increase in VOR gain. Covert back-up compensatory saccade amplitude increased 0.4° for every 0.1 increase in VOR gain. Conclusion: We observed significant relationships between VOR gain and compensatory saccades in healthy older adults. Lower VOR gain was associated with larger amplitude, shorter latency compensatory saccades. Compensatory saccades reflect underlying rotational vestibular hypofunction, and may be particularly useful at identifying partial vestibular deficits as occur in aging adults. PMID:27445793

  20. MEvoLib v1.0: the first molecular evolution library for Python.

    PubMed

    Álvarez-Jarreta, Jorge; Ruiz-Pesini, Eduardo

    2016-10-28

    Molecular evolution studies involve many different hard computational problems solved, in most cases, with heuristic algorithms that provide a nearly optimal solution. Hence, diverse software tools exist for the different stages involved in a molecular evolution workflow. We present MEvoLib, the first molecular evolution library for Python, providing a framework to work with different tools and methods involved in the common tasks of molecular evolution workflows. In contrast with already existing bioinformatics libraries, MEvoLib is focused on the stages involved in molecular evolution studies, enclosing the set of tools with a common purpose in a single high-level interface with fast access to their frequent parameterizations. The gene clustering from partial or complete sequences has been improved with a new method that integrates accessible external information (e.g. GenBank's features data). Moreover, MEvoLib adjusts the fetching process from NCBI databases to optimize the download bandwidth usage. In addition, it has been implemented using parallelization techniques to cope with even large-case scenarios. MEvoLib is the first library for Python designed to facilitate molecular evolution researches both for expert and novel users. Its unique interface for each common task comprises several tools with their most used parameterizations. It has also included a method to take advantage of biological knowledge to improve the gene partition of sequence datasets. Additionally, its implementation incorporates parallelization techniques to enhance computational costs when handling very large input datasets.

  1. Rates of molecular evolution in tree ferns are associated with body size, environmental temperature, and biological productivity.

    PubMed

    Barrera-Redondo, Josué; Ramírez-Barahona, Santiago; Eguiarte, Luis E

    2018-05-01

    Variation in rates of molecular evolution (heterotachy) is a common phenomenon among plants. Although multiple theoretical models have been proposed, fundamental questions remain regarding the combined effects of ecological and morphological traits on rate heterogeneity. Here, we used tree ferns to explore the correlation between rates of molecular evolution in chloroplast DNA sequences and several morphological and environmental factors within a Bayesian framework. We revealed direct and indirect effects of body size, biological productivity, and temperature on substitution rates, where smaller tree ferns living in warmer and less productive environments tend to have faster rates of molecular evolution. In addition, we found that variation in the ratio of nonsynonymous to synonymous substitution rates (dN/dS) in the chloroplast rbcL gene was significantly correlated with ecological and morphological variables. Heterotachy in tree ferns may be influenced by effective population size associated with variation in body size and productivity. Macroevolutionary hypotheses should go beyond explaining heterotachy in terms of mutation rates and instead, should integrate population-level factors to better understand the processes affecting the tempo of evolution at the molecular level. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  2. Clinical identification of compensatory structures on projective tests: a self psychological approach.

    PubMed

    Silverstein, M L

    2001-06-01

    In this article I discuss compensatory structure, a concept from Kohut's (1971, 1977) psychology of the self that is not as familiar as Kohut's other views about the self. Compensatory structures are attempts to repair selfobject failure, usually by strengthening idealization or twinship in the face of mirroring deficits. Compensatory structures, particularly their early indications, can be detected on projective tests for identifying adaptive resources and treatment potential. The clinical identification of compensatory structures on test findings is described using Rorschach and Thematic Apperception Test (Murray, 1943) content. Particular attention is devoted to the 2-part process of demonstrating first, an injury to the self, and second, how attempts to recover from such injuries can be detected on projective tests. Clinical examples are provided, and the differentiation between compensatory structures and defenses and sublimation is discussed.

  3. Influence of gait speed on stability: recovery from anterior slips and compensatory stepping.

    PubMed

    Bhatt, T; Wening, J D; Pai, Y-C

    2005-02-01

    Falls precipitated by slipping are a major health concern, with the majority of all slip-related falls occurring during gait. Recent evidence shows that a faster and/or more anteriorly positioned center of mass (COM) is more stable against backward balance loss, and that compensatory stepping is the key to recovering stability upon balance loss. The purposes of this paper were to determine whether walking speed affected gait stability for backward balance loss at slip onset and touchdown of compensatory stepping, and whether compensatory stepping response resembled the regular gait pattern. Forty-seven young subjects were slipped unexpectedly either at a self-selected fast, natural or slow speed. Speed-related differences in stability at slip onset and touchdown of the subsequent compensatory step were analyzed using the COM position-velocity state. The results indicate that gait speed highly correlated with stability against backward balance loss at slip onset. The low COM velocity of the slow group was not sufficiently compensated for by a more anteriorly positioned COM associated with a shorter step length at slip onset. At touchdown of the compensatory step, the speed-related differences in stability diminished, due to the continued advantage of anterior COM positioning from a short compensatory step retained by the slow group, coupled with an increase in COM velocity. Compensatory step length and relative COM position altered as a function of gait speed, indicating the motor program for gait regulation may play a role in modulating the compensatory step.

  4. The role of cognitive reserve and memory self-efficacy in compensatory strategy use: A structural equation approach.

    PubMed

    Simon, Christa; Schmitter-Edgecombe, Maureen

    2016-08-01

    The use of compensatory strategies plays an important role in the ability of older adults to adapt to late-life memory changes. Even with the benefits associated with compensatory strategy use, little research has explored specific mechanisms associated with memory performance and compensatory strategies. Rather than an individual's objective memory performance directly predicting their use of compensatory strategies, it is possible that some other variables are indirectly influencing that relationship. The purpose of this study was to: (a) examine the moderating effects of cognitive reserve (CR) and (b) evaluate the potential mediating effects of memory self-efficacy on the relationship between objective memory performance and compensatory strategy use. Two structural equation models (SEM) were used to evaluate CR (latent moderator model) and memory self-efficacy (mediator model) in a sample of 155 community-dwelling older adults over the age of 55. The latent variable moderator model indicated that CR was not substantiated as a moderator variable in this sample (p = .861). However, memory self-efficacy significantly mediated the association between objective memory performance and compensatory strategy use (β = .22, 95% confidence interval, CI [.002, .437]). More specifically, better objective memory was associated with lower compensatory strategy use because of its relation to higher memory self-efficacy. These findings provide initial support for an explanatory framework of the relation between objective memory and compensatory strategy use in a healthy older adult population by identifying the importance of an individual's memory perceptions.

  5. Viral evolution in HLA-B27-restricted CTL epitopes in human immunodeficiency virus type 1-infected individuals.

    PubMed

    Setiawan, Laurentia C; Gijsbers, Esther F; van Nuenen, Adrianus C; Kootstra, Neeltje A

    2015-08-01

    The HLA-B27 allele is over-represented among human immunodeficiency virus type 1-infected long-term non-progressors. In these patients, strong CTL responses targeting HLA-B27-restricted viral epitopes have been associated with long-term asymptomatic survival. Indeed, loss of control of viraemia in HLA-B27 patients has been associated with CTL escape at position 264 in the immunodominant KK10 epitope. This CTL escape mutation in the viral Gag protein has been associated with severe viral attenuation and may require the presence of compensatory mutations before emerging. Here, we studied sequence evolution within HLA-B27-restricted CTL epitopes in the viral Gag protein during the course of infection of seven HLA-B27-positive patients. Longitudinal gag sequences obtained at different time points around the time of AIDS diagnosis were obtained and analysed for the presence of mutations in epitopes restricted by HLA-B27, and for potential compensatory mutations. Sequence variations were observed in the HLA-B27-restricted CTL epitopes IK9 and DR11, and the immunodominant KK10 epitope. However, the presence of sequence variations in the HLA-B27-restricted CTL epitopes could not be associated with an increase in viraemia in the majority of the patients studied. Furthermore, we observed low genetic diversity in the gag region of the viral variants throughout the course of infection, which is indicative of low viral replication and corresponds to the low viral load observed in the HLA-B27-positive patients. These data indicated that control of viral replication can be maintained in HLA-B27-positive patients despite the emergence of viral mutations in HLA-B27-restricted epitopes.

  6. Compensatory Mitigation Rule Q&A

    EPA Pesticide Factsheets

    What is compensatory mitigation? How is compensatory mitigation accomplished? What does this final rule do? What are the most significant changes required by this rule compared to previous mitigation practices? What are the goals of the final rule?

  7. Why Do Drivers Use Mobile Phones While Driving? The Contribution of Compensatory Beliefs.

    PubMed

    Zhou, Ronggang; Yu, Mengli; Wang, Xinyi

    2016-01-01

    The current study is the first to investigate the contribution of compensatory beliefs (i.e., the belief that the negative effects of an unsafe behavior can be "neutralized" by engaging in another safe behavior; e.g., "I can use a mobile phone now because I will slow down ") on drivers' mobile phone use while driving. The effects of drivers' personal characteristics on compensatory beliefs, mobile phone use and self-regulatory behaviors were also examined. A series of questions were administered to drivers, which included (1) personal measures, (2) scales that measured compensatory beliefs generally in substance use and with regard to driving safety, and (3) questions to measure drivers' previous primary mobile phone usage and corresponding self-regulatory actions. Overall, drivers reported a low likelihood of compensatory beliefs, prior mobile phone use, and a strong frequency of self-regulatory behaviors. Respondents who had a higher tendency toward compensatory beliefs reported more incidents or crash involvement caused by making or answering calls and sending or reading messages. The findings provide strong support for the contribution of compensatory beliefs in predicting mobile phone usage in the context of driving. Compensatory beliefs can explain 41% and 43% of the variance in the active activities of making calls and texting/sending messages compared with 18% and 31% of the variance in the passive activities of answering calls and reading messages. Among the regression models for predicting self-regulatory behaviors at the tactical or operational level, compensatory beliefs emerge as significant predictors only in predicting shorter conversations while on a call. The findings and limitations of the current study are discussed.

  8. The Role of Microbial Community Composition in Controlling Soil Respiration Responses to Temperature

    PubMed Central

    Khachane, Amit; Dungait, Jennifer A. J.; Fraser, Fiona; Hopkins, David W.; Wookey, Philip A.; Singh, Brajesh K.; Freitag, Thomas E.; Hartley, Iain P.; Prosser, James I.

    2016-01-01

    Rising global temperatures may increase the rates of soil organic matter decomposition by heterotrophic microorganisms, potentially accelerating climate change further by releasing additional carbon dioxide (CO2) to the atmosphere. However, the possibility that microbial community responses to prolonged warming may modify the temperature sensitivity of soil respiration creates large uncertainty in the strength of this positive feedback. Both compensatory responses (decreasing temperature sensitivity of soil respiration in the long-term) and enhancing responses (increasing temperature sensitivity) have been reported, but the mechanisms underlying these responses are poorly understood. In this study, microbial biomass, community structure and the activities of dehydrogenase and β-glucosidase enzymes were determined for 18 soils that had previously demonstrated either no response or varying magnitude of enhancing or compensatory responses of temperature sensitivity of heterotrophic microbial respiration to prolonged cooling. The soil cooling approach, in contrast to warming experiments, discriminates between microbial community responses and the consequences of substrate depletion, by minimising changes in substrate availability. The initial microbial community composition, determined by molecular analysis of soils showing contrasting respiration responses to cooling, provided evidence that the magnitude of enhancing responses was partly related to microbial community composition. There was also evidence that higher relative abundance of saprophytic Basidiomycota may explain the compensatory response observed in one soil, but neither microbial biomass nor enzymatic capacity were significantly affected by cooling. Our findings emphasise the key importance of soil microbial community responses for feedbacks to global change, but also highlight important areas where our understanding remains limited. PMID:27798702

  9. The Role of Microbial Community Composition in Controlling Soil Respiration Responses to Temperature.

    PubMed

    Auffret, Marc D; Karhu, Kristiina; Khachane, Amit; Dungait, Jennifer A J; Fraser, Fiona; Hopkins, David W; Wookey, Philip A; Singh, Brajesh K; Freitag, Thomas E; Hartley, Iain P; Prosser, James I

    2016-01-01

    Rising global temperatures may increase the rates of soil organic matter decomposition by heterotrophic microorganisms, potentially accelerating climate change further by releasing additional carbon dioxide (CO2) to the atmosphere. However, the possibility that microbial community responses to prolonged warming may modify the temperature sensitivity of soil respiration creates large uncertainty in the strength of this positive feedback. Both compensatory responses (decreasing temperature sensitivity of soil respiration in the long-term) and enhancing responses (increasing temperature sensitivity) have been reported, but the mechanisms underlying these responses are poorly understood. In this study, microbial biomass, community structure and the activities of dehydrogenase and β-glucosidase enzymes were determined for 18 soils that had previously demonstrated either no response or varying magnitude of enhancing or compensatory responses of temperature sensitivity of heterotrophic microbial respiration to prolonged cooling. The soil cooling approach, in contrast to warming experiments, discriminates between microbial community responses and the consequences of substrate depletion, by minimising changes in substrate availability. The initial microbial community composition, determined by molecular analysis of soils showing contrasting respiration responses to cooling, provided evidence that the magnitude of enhancing responses was partly related to microbial community composition. There was also evidence that higher relative abundance of saprophytic Basidiomycota may explain the compensatory response observed in one soil, but neither microbial biomass nor enzymatic capacity were significantly affected by cooling. Our findings emphasise the key importance of soil microbial community responses for feedbacks to global change, but also highlight important areas where our understanding remains limited.

  10. Religious belief as compensatory control.

    PubMed

    Kay, Aaron C; Gaucher, Danielle; McGregor, Ian; Nash, Kyle

    2010-02-01

    The authors review experimental evidence that religious conviction can be a defensive source of compensatory control when personal or external sources of control are low. They show evidence that (a) belief in religious deities and secular institutions can serve as external forms of control that can compensate for manipulations that lower personal control and (b) religious conviction can also serve as compensatory personal control after experimental manipulations that lower other forms of personal or external control. The authors review dispositional factors that differentially orient individuals toward external or personal varieties of compensatory control and conclude that compensatory religious conviction can be a flexible source of personal and external control for relief from the anxiety associated with random and uncertain experiences.

  11. The Influence of Tactual Seat-motion Cues on Training and Performance in a Roll-axis Compensatory Tracking Task Setting

    DTIC Science & Technology

    2008-05-01

    AFRL-RH-WP-SR-2009-0002 The Influence of Tactual Seat-motion Cues on Training and Performance in a Roll-axis Compensatory Tracking Task...and Performance in a Roll-axis Compensatory Tracking Task Setting 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62202F 6. AUTHOR(S...simulated vehicle having aircraft-like dynamics. A centrally located compensatory display, subtending about nine degrees, provided visual roll error

  12. Prospective memory rehabilitation using smartphones in patients with TBI: What do participants report?

    PubMed

    Evald, Lars

    2015-01-01

    Use of assistive devices has been shown to be beneficial as a compensatory memory strategy among brain injury survivors, but little is known about possible advantages and disadvantages of the technology. As part of an intervention study participants were interviewed about their experiences with the use of low-cost, off-the-shelf, unmodified smartphones combined with Internet calendars as a compensatory memory strategy. Thirteen community-dwelling patients with traumatic brain injury (TBI) received a 6-week group-based instruction in the systematic use of a smartphone as a memory compensatory aid followed by a brief structured open-ended interview regarding satisfaction with and advantages and disadvantages of the compensatory strategy. Ten of 13 participants continued to use a smartphone as their primary compensatory strategy. Audible and visual reminders were the most frequently mentioned advantages of the smartphone, and, second, the capability as an all-in-one memory device. In contrast, battery life was the most often mentioned disadvantage, followed by concerns about loss or failure of the device. Use of a smartphone seems to be a satisfactory compensatory memory strategy to many patients with TBI and smartphones come with features that are advantageous to other compensatory strategies. However, some benefits come hand-in-hand with drawbacks, such as the feeling of dependency. These aspects should be taken into account when choosing assistive technology as a memory compensatory strategy.

  13. Is compensatory hyperhidrosis after thoracic sympathicotomy in palmar hyperhidrosis patients related to the excitability of thoracic sympathetic ganglions?

    PubMed Central

    Chen, Jun-Peng; Peng, A-Jing; Xu, Chen-Hui; Li, Guo-Ying

    2017-01-01

    Background The mechanism of compensatory hyperhidrosis remains unclear. The aim of this study was to explore the relationship between compensatory hyperhidrosis and thoracic sympathetic ganglion excitability to assess the effectiveness of thoracoscopic T4 sympathicotomy for treating palmar hyperhidrosis. Methods Sixty-six cases of T4 sympathetic ganglions were prospectively collected from patients with palmar hyperhidrosis who underwent thoracoscopic T4 sympathicotomy from 2013 to 2016 in our department. The expression levels of choline acetyltransferase (ChAT), vasoactive intestinal peptide (VIP), and synaptophysin were detected using immunohistochemistry. Patients with palmar hyperhidrosis were followed-up for examination of postoperative sweating status. Results Thirty-eight cases (57.6%) of compensatory hyperhidrosis were identified. Mild compensatory hyperhidrosis occurred in 26 patients (39.4%), moderate in 11 (16.7%), and severe in 1 (1.5%). The rate of compensatory hyperhidrosis was higher in patients with axilla hyperhidrosis than those without (76.0% vs. 46.3%, P=0.018). However, the clinical data were similar between the compensatory hyperhidrosis group and the no compensatory hyperhidrosis group. In addition, the ChAT, VIP, and synaptophysin expression levels were not significantly different between the two groups (P values of 0.356, 0.071, and 0.141, respectively). Furthermore, the ChAT, VIP, and synaptophysin expression levels in the mild group were similar to those observed in the moderate/intense group (P values of 0.089, 0.124, and 0.149, respectively). The remission rate was 100% in palmar hyperhidrosis, 48.2% (27/56) in pedal hyperhidrosis, 56.0% (14/25) in axilla hyperhidrosis and 88.9% (16/18) in skin symptoms. No signs of chapped skin on the palms were found. Conclusions There was no significant correlation between compensatory hyperhidrosis and thoracic sympathetic ganglion excitability; however, compensatory hyperhidrosis is more likely to simultaneously occur in patients with axilla hyperhidrosis. The satisfactory efficacy of thoracoscopic T4 sympathicotomy indicates that it may an ideal technique for palmar hyperhidrosis. PMID:29221281

  14. The Compensatory ADHD Behaviors Scale (CABS): Development and Initial Validation.

    PubMed

    Castagna, Peter J; Roye, Scott; Calamia, Matthew

    2018-05-01

    Several measures are available that assess inattention, hyperactivity/impulsivity, and executive functioning deficits. Treatments for adults with attention-deficit/hyperactivity disorder (ADHD) and skill-based academic interventions focus on improving compensatory strategies to ameliorate functional impairment; however, no measure exists that examines the compensatory behaviors adults utilize to compensate for the functional deficits associated with inattention and hyperactivity/impulsivity. The current study aimed to determine the psychometric properties of the Compensatory ADHD Behaviors Scale (CABS). Five-hundred participants ( M age = 36.83, SD = 11.57) completed measures of ADHD symptomatology, executive functioning, functional impairment, mood disorder symptoms, and the CABS. Analyses revealed that scales assessing both use and effectiveness of compensatory behaviors subscales had similar factor structures, reflecting present- and future-oriented behaviors. The present-, but not future-oriented, behaviors significantly related to ADHD symptomatology, executive dysfunction, and functional impairment; effectiveness of present-oriented compensatory behaviors demonstrated incremental validity in predicting impairment. Compensatory strategies may be a useful variable to measure when examining functional impairment associated with inattention and hyperactivity/impulsivity. The current study provides preliminary evidence of the ability of CABS to validly measure various strategies associated with (clinical and subclinical) ADHD symptomatology, executive functioning, and overall impairment.

  15. Eco-compensation in China: Theory, practices and suggestions for the future.

    PubMed

    Shang, Wenxiu; Gong, Yicheng; Wang, Zhongjing; Stewardson, Michael J

    2018-03-15

    Eco-compensation is the most important form of compensatory conservation in China. However, this compensatory mechanism is criticized for vague definition and massive government participation. For better understanding of eco-compensation in China, this paper compares theories and practices of compensatory mechanisms in China and abroad. The analysis of theoretical backgrounds shows that eco-compensation in China is a combination of 'ecological compensation' and 'payments for ecosystem services'. Ten compensatory projects in China and abroad are assessed to reveal characteristics and problems of eco-compensation in China. The results show that compensatory projects in China lagged behind mature foreign compensatory projects in clarity of property rights, responsibility fulfillment, executive efficiency, effectiveness, sustainability and equality. The massive participation of the government is the major reason for the poor performance of compensatory projects in China. However, government participation is necessary at the present stage in China for the income gap and beneficiaries' low willingness to pay. For the improvement of eco-compensation in China, suggestions are given on the choice of non-market valuation methods, the creation of property rights and the establishment of market mechanisms. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Hippocampal Plasticity During the Progression of Alzheimer’s disease

    PubMed Central

    Mufson, Elliott J.; Mahady, Laura; Waters, Diana; Counts, Scott E.; Perez, Sylvia E.; DeKosky, Steven; Ginsberg, Stephen D.; Ikonomovic, Milos D.; Scheff, Stephen; Binder, Lester

    2015-01-01

    Neuroplasticity involves molecular changes in central nervous system (CNS) synaptic structure and function throughout life. The concept of neural organization allows for synaptic remodeling as a compensatory mechanism to the early pathobiology of Alzheimer’s disease (AD) in an attempt to maintain brain function and cognition during the onset of dementia. The hippocampus, a crucial component of the medial temporal lobe memory circuit, is affected early in AD and displays synaptic and intraneuronal molecular remodeling against a pathological background of extracellular amyloid-beta (Aβ) deposition and intracellular neurofibrillary tangle (NFT) formation in the early stages of AD. Here we discuss human clinical pathological findings supporting the concept that the hippocampus is capable of neural plasticity during mild cognitive impairment (MCI), a prodromal stage of AD and early stage AD. PMID:25772787

  17. Abrupt deceleration of molecular evolution linked to the origin of arborescence in ferns.

    PubMed

    Korall, Petra; Schuettpelz, Eric; Pryer, Kathleen M

    2010-09-01

    Molecular rate heterogeneity, whereby rates of molecular evolution vary among groups of organisms, is a well-documented phenomenon. Nonetheless, its causes are poorly understood. For animals, generation time is frequently cited because longer-lived species tend to have slower rates of molecular evolution than their shorter-lived counterparts. Although a similar pattern has been uncovered in flowering plants, using proxies such as growth form, the underlying process has remained elusive. Here, we find a deceleration of molecular evolutionary rate to be coupled with the origin of arborescence in ferns. Phylogenetic branch lengths within the “tree fern” clade are considerably shorter than those of closely related lineages, and our analyses demonstrate that this is due to a significant difference in molecular evolutionary rate. Reconstructions reveal that an abrupt rate deceleration coincided with the evolution of the long-lived tree-like habit at the base of the tree fern clade. This suggests that a generation time effect may well be ubiquitous across the green tree of life, and that the search for a responsible mechanism must focus on characteristics shared by all vascular plants. Discriminating among the possibilities will require contributions from various biological disciplines,but will be necessary for a full appreciation of molecular evolution.

  18. Why Do Drivers Use Mobile Phones While Driving? The Contribution of Compensatory Beliefs

    PubMed Central

    Zhou, Ronggang; Yu, Mengli; Wang, Xinyi

    2016-01-01

    The current study is the first to investigate the contribution of compensatory beliefs (i.e., the belief that the negative effects of an unsafe behavior can be "neutralized" by engaging in another safe behavior; e.g., "I can use a mobile phone now because I will slow down ") on drivers’ mobile phone use while driving. The effects of drivers’ personal characteristics on compensatory beliefs, mobile phone use and self-regulatory behaviors were also examined. A series of questions were administered to drivers, which included (1) personal measures, (2) scales that measured compensatory beliefs generally in substance use and with regard to driving safety, and (3) questions to measure drivers’ previous primary mobile phone usage and corresponding self-regulatory actions. Overall, drivers reported a low likelihood of compensatory beliefs, prior mobile phone use, and a strong frequency of self-regulatory behaviors. Respondents who had a higher tendency toward compensatory beliefs reported more incidents or crash involvement caused by making or answering calls and sending or reading messages. The findings provide strong support for the contribution of compensatory beliefs in predicting mobile phone usage in the context of driving. Compensatory beliefs can explain 41% and 43% of the variance in the active activities of making calls and texting/sending messages compared with 18% and 31% of the variance in the passive activities of answering calls and reading messages. Among the regression models for predicting self-regulatory behaviors at the tactical or operational level, compensatory beliefs emerge as significant predictors only in predicting shorter conversations while on a call. The findings and limitations of the current study are discussed. PMID:27494524

  19. Proceedings: Conference on Compensatory/Remedial Education.

    ERIC Educational Resources Information Center

    Fea, Henry R., Ed.; And Others

    This document presents the papers and discussions from the Conference on Compensatory/Remedial Education. The contents include: "Institutional Programs for the Low Achievers" by Joan G. Roloff; "Communication in Compensatory Education" by Henry R. Fea; "Seminar: Special Programs for Minorities" by Constance Acholonu; "Seminar: Special Programs for…

  20. 49 CFR 91.7 - Determination of compensatory charges.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Determination of compensatory charges. 91.7 Section 91.7 Transportation Office of the Secretary of Transportation INTERNATIONAL AIR TRANSPORTATION FAIR COMPETITIVE PRACTICES § 91.7 Determination of compensatory charges. (a) Upon indication by the...

  1. 5 CFR 551.531 - Compensatory time off.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Compensatory time off. 551.531 Section 551.531 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION UNDER THE FAIR LABOR STANDARDS ACT Overtime Pay Provisions Compensatory Time Off § 551.531...

  2. Phylogenetic estimates of diversification rate are affected by molecular rate variation.

    PubMed

    Duchêne, D A; Hua, X; Bromham, L

    2017-10-01

    Molecular phylogenies are increasingly being used to investigate the patterns and mechanisms of macroevolution. In particular, node heights in a phylogeny can be used to detect changes in rates of diversification over time. Such analyses rest on the assumption that node heights in a phylogeny represent the timing of diversification events, which in turn rests on the assumption that evolutionary time can be accurately predicted from DNA sequence divergence. But there are many influences on the rate of molecular evolution, which might also influence node heights in molecular phylogenies, and thus affect estimates of diversification rate. In particular, a growing number of studies have revealed an association between the net diversification rate estimated from phylogenies and the rate of molecular evolution. Such an association might, by influencing the relative position of node heights, systematically bias estimates of diversification time. We simulated the evolution of DNA sequences under several scenarios where rates of diversification and molecular evolution vary through time, including models where diversification and molecular evolutionary rates are linked. We show that commonly used methods, including metric-based, likelihood and Bayesian approaches, can have a low power to identify changes in diversification rate when molecular substitution rates vary. Furthermore, the association between the rates of speciation and molecular evolution rate can cause the signature of a slowdown or speedup in speciation rates to be lost or misidentified. These results suggest that the multiple sources of variation in molecular evolutionary rates need to be considered when inferring macroevolutionary processes from phylogenies. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  3. Enhanced mitochondrial complex gene function and reduced liver size may mediate improved feed efficiency of beef cattle during compensatory growth

    USDA-ARS?s Scientific Manuscript database

    Growing ruminants maintained under dietary restriction for extended periods will exhibit compensatory growth when reverted to ad libitum feeding. This period of compensatory growth is associated with increased feed efficiency, lower basal energy requirements, and changes in circulating concentration...

  4. Compensatory Education Services.

    ERIC Educational Resources Information Center

    National Inst. of Education (DHEW), Washington, DC.

    This is the first of six reports on compensatory education services. The purpose of this report is to describe the compensatory education services provided by a cross section of the 14,000 school districts that receive Elementary Secondary Education Act Title I funds. It provides a factual background for the other reports in this series. This…

  5. 78 FR 55765 - Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire Protection (CARMEN...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-11

    ... Nuclear Power Plant Fire Protection (CARMEN-FIRE) AGENCY: Nuclear Regulatory Commission. ACTION: Draft..., ``Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire Protection (CARMEN-FIRE).'' In... integral part of NRC-approved fire protection programs. However, compensatory measures are not expected to...

  6. Musical emotions: Functions, origins, evolution

    NASA Astrophysics Data System (ADS)

    Perlovsky, Leonid

    2010-03-01

    Theories of music origins and the role of musical emotions in the mind are reviewed. Most existing theories contradict each other, and cannot explain mechanisms or roles of musical emotions in workings of the mind, nor evolutionary reasons for music origins. Music seems to be an enigma. Nevertheless, a synthesis of cognitive science and mathematical models of the mind has been proposed describing a fundamental role of music in the functioning and evolution of the mind, consciousness, and cultures. The review considers ancient theories of music as well as contemporary theories advanced by leading authors in this field. It addresses one hypothesis that promises to unify the field and proposes a theory of musical origin based on a fundamental role of music in cognition and evolution of consciousness and culture. We consider a split in the vocalizations of proto-humans into two types: one less emotional and more concretely-semantic, evolving into language, and the other preserving emotional connections along with semantic ambiguity, evolving into music. The proposed hypothesis departs from other theories in considering specific mechanisms of the mind-brain, which required the evolution of music parallel with the evolution of cultures and languages. Arguments are reviewed that the evolution of language toward becoming the semantically powerful tool of today required emancipation from emotional encumbrances. The opposite, no less powerful mechanisms required a compensatory evolution of music toward more differentiated and refined emotionality. The need for refined music in the process of cultural evolution is grounded in fundamental mechanisms of the mind. This is why today's human mind and cultures cannot exist without today's music. The reviewed hypothesis gives a basis for future analysis of why different evolutionary paths of languages were paralleled by different evolutionary paths of music. Approaches toward experimental verification of this hypothesis in psychological and neuroimaging research are reviewed.

  7. Diversification and the evolution of dispersal ability in the tribe Brassiceae (Brassicaceae).

    PubMed

    Willis, C G; Hall, J C; Rubio de Casas, R; Wang, T Y; Donohue, K

    2014-12-01

    Dispersal and establishment ability can influence evolutionary processes such as geographic isolation, adaptive divergence and extinction probability. Through these population-level dynamics, dispersal ability may also influence macro-evolutionary processes such as species distributions and diversification. This study examined patterns of evolution of dispersal-related fruit traits, and how the evolution of these traits is correlated with shifts in geographic range size, habitat and diversification rates in the tribe Brassiceae (Brassicaceae). The phylogenetic analysis included 72 taxa sampled from across the Brassiceae and included both nuclear and chloroplast markers. Dispersal-related fruit characters were scored and climate information for each taxon was retrieved from a database. Correlations between fruit traits, seed characters, habitat, range and climate were determined, together with trait-dependent diversification rates. It was found that the evolution of traits associated with limited dispersal evolved only in association with compensatory traits that increase dispersal ability. The evolution of increased dispersal ability occurred in multiple ways through the correlated evolution of different combinations of fruit traits. The evolution of traits that increase dispersal ability was in turn associated with larger seed size, increased geographic range size and higher diversification rates. This study provides evidence that the evolution of increased dispersal ability and larger seed size, which may increase establishment ability, can also influence macro-evolutionary processes, possibly by increasing the propensity for long-distance dispersal. In particular, it may increase speciation and consequent diversification rates by increasing the likelihood of geographic and thereby reproductive isolation. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Molecular evolution tracks macroevolutionary transitions in Cetacea.

    PubMed

    McGowen, Michael R; Gatesy, John; Wildman, Derek E

    2014-06-01

    Cetacea (whales, dolphins, and porpoises) is a model group for investigating the molecular signature of macroevolutionary transitions. Recent research has begun to reveal the molecular underpinnings of the remarkable anatomical and behavioral transformation in this clade. This shift from terrestrial to aquatic environments is arguably the best-understood major morphological transition in vertebrate evolution. The ancestral body plan and physiology were extensively modified and, in many cases, these crucial changes are recorded in cetacean genomes. Recent studies have highlighted cetaceans as central to understanding adaptive molecular convergence and pseudogene formation. Here, we review current research in cetacean molecular evolution and the potential of Cetacea as a model for the study of other macroevolutionary transitions from a genomic perspective. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Compensatory Advantage as a Mechanism of Educational Inequality: A Regression Discontinuity Based on Month of Birth

    ERIC Educational Resources Information Center

    Bernardi, Fabrizio

    2014-01-01

    Compensatory advantage is a mechanism of social stratification that complements cumulative advantage and path dependence. In this article, I first discuss the theoretical foundations of the compensatory advantage and path dependence mechanisms and the methodological challenges that complicate identification of their effects. Next, I present a…

  10. 30 CFR 256.72 - Compensatory payments as production.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... INTERIOR OFFSHORE LEASING OF SULPHUR OR OIL AND GAS IN THE OUTER CONTINENTAL SHELF Assignments, Transfers, and Extensions § 256.72 Compensatory payments as production. If an oil and gas lessee makes compensatory payments and if the lease is not being maintained in force by other production of oil or gas in...

  11. 29 CFR 553.20 - Introduction.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... required under section 7. Compensatory time received by an employee in lieu of cash must be at the rate of not less than one and one-half hours of compensatory time for each hour of overtime work, just as the... Time and Compensatory Time Off § 553.20 Introduction. Section 7 of the FLSA requires that covered...

  12. Predictive procedure for compensatory hyperhidrosis before sympathectomy: preliminary findings.

    PubMed

    Jeong, Jin Yong; Park, Hyung Joo; Park, Jae Kil; Jo, Keon Hyeon; Wang, Young Pil; Lee, Jongho; Shin, Jae Seong

    2014-08-01

    Compensatory hyperhidrosis is one of the most common and serious adverse effects following sympathectomy. We performed a local anesthetic procedure that predicts the occurrence and severity of compensatory hyperhidrosis, and evaluated the feasibility, safety, and efficacy of the procedure. From July 2009 to July 2010, 20 patients with severe primary palmar hyperhidrosis underwent predictive procedures. A sympathetic nerve block was obtained via thoracoscopic approach under local anesthesia. The patients were evaluated for compensatory hyperhidrosis 1 week after the procedure before deciding whether to proceed with sympathectomy. Of the 20 patients, 17 patients proceeded with sympathectomy and 3 refused the final procedure. Following sympathectomy, the occurrence and severity of compensatory hyperhidrosis in the remaining 17 patients were statistically analyzed with two tailed paired t test, and there is no significant difference between the predictive and final procedures (t = 1.69, df = 16, p > 0.1). Predictive procedure using local anesthesia to detect compensatory hyperhidrosis before sympathectomy may be useful for helping patients to decide whether to undergo the operation. Georg Thieme Verlag KG Stuttgart · New York.

  13. Stem cell plasticity enables hair regeneration following Lgr5+ cell loss.

    PubMed

    Hoeck, Joerg D; Biehs, Brian; Kurtova, Antonina V; Kljavin, Noelyn M; de Sousa E Melo, Felipe; Alicke, Bruno; Koeppen, Hartmut; Modrusan, Zora; Piskol, Robert; de Sauvage, Frederic J

    2017-06-01

    Under injury conditions, dedicated stem cell populations govern tissue regeneration. However, the molecular mechanisms that induce stem cell regeneration and enable plasticity are poorly understood. Here, we investigate stem cell recovery in the context of the hair follicle to understand how two molecularly distinct stem cell populations are integrated. Utilizing diphtheria-toxin-mediated cell ablation of Lgr5 + (leucine-rich repeat-containing G-protein-coupled receptor 5) stem cells, we show that killing of Lgr5 + cells in mice abrogates hair regeneration but this is reversible. During recovery, CD34 + (CD34 antigen) stem cells activate inflammatory response programs and start dividing. Pharmacological attenuation of inflammation inhibits CD34 + cell proliferation. Subsequently, the Wnt pathway controls the recovery of Lgr5 + cells and inhibition of Wnt signalling prevents Lgr5 + cell and hair germ recovery. Thus, our study uncovers a compensatory relationship between two stem cell populations and the underlying molecular mechanisms that enable hair follicle regeneration.

  14. Toxin structures as evolutionary tools: Using conserved 3D folds to study the evolution of rapidly evolving peptides.

    PubMed

    Undheim, Eivind A B; Mobli, Mehdi; King, Glenn F

    2016-06-01

    Three-dimensional (3D) structures have been used to explore the evolution of proteins for decades, yet they have rarely been utilized to study the molecular evolution of peptides. Here, we highlight areas in which 3D structures can be particularly useful for studying the molecular evolution of peptide toxins. Although we focus our discussion on animal toxins, including one of the most widespread disulfide-rich peptide folds known, the inhibitor cystine knot, our conclusions should be widely applicable to studies of the evolution of disulfide-constrained peptides. We show that conserved 3D folds can be used to identify evolutionary links and test hypotheses regarding the evolutionary origin of peptides with extremely low sequence identity; construct accurate multiple sequence alignments; and better understand the evolutionary forces that drive the molecular evolution of peptides. Also watch the video abstract. © 2016 WILEY Periodicals, Inc.

  15. Putative Independent Evolutionary Reversals from Genotypic to Temperature-Dependent Sex Determination are Associated with Accelerated Evolution of Sex-Determining Genes in Turtles.

    PubMed

    Literman, Robert; Burrett, Alexandria; Bista, Basanta; Valenzuela, Nicole

    2018-01-01

    The evolutionary lability of sex-determining mechanisms across the tree of life is well recognized, yet the extent of molecular changes that accompany these repeated transitions remain obscure. Most turtles retain the ancestral temperature-dependent sex determination (TSD) from which multiple transitions to genotypic sex determination (GSD) occurred independently, and two contrasting hypotheses posit the existence or absence of reversals back to TSD. Here we examined the molecular evolution of the coding regions of a set of gene regulators involved in gonadal development in turtles and several other vertebrates. We found slower molecular evolution in turtles and crocodilians compared to other vertebrates, but an acceleration in Trionychia turtles and at some phylogenetic branches demarcating major taxonomic diversification events. Of all gene classes examined, hormone signaling genes, and Srd5a1 in particular, evolve faster in many lineages and especially in turtles. Our data show that sex-linked genes do not follow a ubiquitous nor uniform pattern of molecular evolution. We then evaluated turtle nucleotide and protein evolution under two evolutionary hypotheses with or without GSD-to-TSD reversals, and found that when GSD-to-TSD reversals are considered, all transitional branches irrespective of direction, exhibit accelerated molecular evolution of nucleotide sequences, while GSD-to-TSD transitional branches also show acceleration in protein evolution. Significant changes in predicted secondary structure that may affect protein function were identified in three genes that exhibited hastened evolution in turtles compared to other vertebrates or in transitional versus non-transitional branches within turtles, rendering them candidates for a key role during SDM evolution in turtles.

  16. Evolution of branched regulatory genetic pathways: directional selection on pleiotropic loci accelerates developmental system drift.

    PubMed

    Johnson, Norman A; Porter, Adam H

    2007-01-01

    Developmental systems are regulated by a web of interacting loci. One common and useful approach in studying the evolution of development is to focus on classes of interacting elements within these systems. Here, we use individual-based simulations to study the evolution of traits controlled by branched developmental pathways involving three loci, where one locus regulates two different traits. We examined the system under a variety of selective regimes. In the case where one branch was under stabilizing selection and the other under directional selection, we observed "developmental system drift": the trait under stabilizing selection showed little phenotypic change even though the loci underlying that trait showed considerable evolutionary divergence. This occurs because the pleiotropic locus responds to directional selection and compensatory mutants are then favored in the pathway under stabilizing selection. Though developmental system drift may be caused by other mechanisms, it seems likely that it is accelerated by the same underlying genetic mechanism as that producing the Dobzhansky-Muller incompatibilities that lead to speciation in both linear and branched pathways. We also discuss predictions of our model for developmental system drift and how different selective regimes affect probabilities of speciation in the branched pathway system.

  17. The Eyes Have It: A Problem-Based Learning Exercise in Molecular Evolution

    ERIC Educational Resources Information Center

    White, Harold B.

    2007-01-01

    Molecular evolution provides an interesting context in which to use problem-based learning because it integrates a variety of topics in biology, biochemistry, and molecular biology. This three-stage problem for advanced students deals with the structure, multiple functions, and properties of lactate dehydrogenase isozymes, and the related…

  18. Chemical evolution of molecular clouds

    NASA Technical Reports Server (NTRS)

    Prasad, Sheo S.; Tarafdar, Sankar P.; Villere, Karen R.; Huntress, Wesley T., Jr.

    1987-01-01

    The principles behind the coupled chemical-dynamical evolution of molecular clouds are described. Particular attention is given to current problems involving the simplest species (i.e., C. CO, O2, and H2) in quiescent clouds. The results of a comparison made between the molecular abundances in the Orion ridge and the hot core (Blake, 1986) are presented.

  19. Has snake fang evolution lost its bite? New insights from a structural mechanics viewpoint.

    PubMed

    Broeckhoven, Chris; du Plessis, Anton

    2017-08-01

    Venomous snakes-the pinnacle of snake evolution-are characterized by their possession of venom-conducting fangs ranging from grooved phenotypes characterizing multiple lineages of rear-fanged taxa to tubular phenotypes present in elapids, viperids and atractaspidines. Despite extensive research, controversy still exists on the selective pressures involved in fang phenotype diversification. Here, we test the hypothesis that larger fangs and consequently a shift to an anterior position in the maxilla evolved to compensate for the costs of structural changes, i.e. higher stress upon impact in tubular fangs compared to grooved fangs. Direct voxel-based stress simulations conducted on high-resolution µCT scans, analysed within a phylogenetic framework, showed no differences in stress distribution between the three fang phenotypes, despite differences in (relative) fang length. These findings suggest that additional compensatory mechanisms are responsible for the biomechanical optimization and that fang length might instead be related to differential striking behaviour strategies. © 2017 The Author(s).

  20. Muscle mitohormesis promotes cellular survival via serine/glycine pathway flux.

    PubMed

    Ost, Mario; Keipert, Susanne; van Schothorst, Evert M; Donner, Verena; van der Stelt, Inge; Kipp, Anna P; Petzke, Klaus-Jürgen; Jove, Mariona; Pamplona, Reinald; Portero-Otin, Manuel; Keijer, Jaap; Klaus, Susanne

    2015-04-01

    Recent studies on mouse and human skeletal muscle (SM) demonstrated the important link between mitochondrial function and the cellular metabolic adaptation. To identify key compensatory molecular mechanisms in response to chronic mitochondrial distress, we analyzed mice with ectopic SM respiratory uncoupling in uncoupling protein 1 transgenic (UCP1-TG) mice as model of muscle-specific compromised mitochondrial function. Here we describe a detailed metabolic reprogramming profile associated with mitochondrial perturbations in SM, triggering an increased protein turnover and amino acid metabolism with induced biosynthetic serine/1-carbon/glycine pathway and the longevity-promoting polyamine spermidine as well as the trans-sulfuration pathway. This is related to an induction of NADPH-generating pathways and glutathione metabolism as an adaptive mitohormetic response and defense against increased oxidative stress. Strikingly, consistent muscle retrograde signaling profiles were observed in acute stress states such as muscle cell starvation and lipid overload, muscle regeneration, and heart muscle inflammation, but not in response to exercise. We provide conclusive evidence for a key compensatory stress-signaling network that preserves cellular function, oxidative stress tolerance, and survival during conditions of increased SM mitochondrial distress, a metabolic reprogramming profile so far only demonstrated for cancer cells and heart muscle. © FASEB.

  1. [Mechanism of population density compensation in island bumblebee taxocenoses (Hymenoptera, Apidae, Bombus) and the notion of reserve compensatory species].

    PubMed

    Bolotov, I N; Kolosova, Iu S; Podbolotskaia, M V; Potapov, G S; Grishchenko, I V

    2013-01-01

    The notion of a dynamic compensatory system is discussed, characterized by the alternation of species occupying the leading position in bumblebee taxocenoses, while the total density of these pollinators in island ecosystems remains at similar levels. The functioning of the compensatory system is regulated by both abiotic factors (the weather and climate) and biotic factors (competition for trophic resources). The stability of the system is determined by the presence of reserve compensatory species capable of rapid population growth against the background of depressed abundance of other species under changing environmental conditions.

  2. The Molecular Basis of Human Brain Evolution.

    PubMed

    Enard, Wolfgang

    2016-10-24

    Humans are a remarkable species, especially because of the remarkable properties of their brain. Since the split from the chimpanzee lineage, the human brain has increased three-fold in size and has acquired abilities for vocal learning, language and intense cooperation. To better understand the molecular basis of these changes is of great biological and biomedical interest. However, all the about 16 million fixed genetic changes that occurred during human evolution are fully correlated with all molecular, cellular, anatomical and behavioral changes that occurred during this time. Hence, as humans and chimpanzees cannot be crossed or genetically manipulated, no direct evidence for linking particular genetic and molecular changes to human brain evolution can be obtained. Here, I sketch a framework how indirect evidence can be obtained and review findings related to the molecular basis of human cognition, vocal learning and brain size. In particular, I discuss how a comprehensive comparative approach, leveraging cellular systems and genomic technologies, could inform the evolution of our brain in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Study on geophone coupling and attenuating compensatory of low-depression velocity layer in desert area

    USGS Publications Warehouse

    Shi, Z.; Tian, G.; Dong, S.; Xia, J.; He, H.; ,

    2004-01-01

    In a desert area, it is difficult to couple geophones with dry sands. A low and depression velocity layer can seriously attenuate high frequency components of seismic data. Therefore, resolution and signal-to-noise (S/N) ratio of seismic data deteriorate. To enhance resolution and S/N ratio of seismic data, we designed a coupling compensatory inverse filter by using the single trace seismic data from Seismic Wave Detect System (SWDS) and common receivers on equal conditions. We designed an attenuating compensatory inverse filter by using seismic data from a microseismogram log. At last, in order to convert a shot gather from common receivers to a shot gather from SWDS, we applied the coupling compensatory inverse filter to the shot gather from common receivers. And then we applied the attenuating compensatory inverse filter to the coupling stacked seismic data to increase its resolution and S/N ratio. The results show that the resolution of seismic data from common receivers after processing by using the coupling compensatory inverse filter is nearly comparable with that of data from SWDS. It is also found that the resolution and S/N ratio have been enhanced after the use of attenuating compensatory inverse filter. From the results, we can conclude that the filters can compensate high frequencies of seismic data. Moreover, the low frequency changed nearly.

  4. State Compensatory Education in New Jersey: The Allocation Formula. Series I.

    ERIC Educational Resources Information Center

    Thomas, Earl Preston

    While it is understood that state compensatory education funds will probably do little to close the gap in public school expenditure levels between wealthy and poor New Jersey districts, it is still important that the educational consumer and the interested observer understand how the system works. Compensatory education funds are the source of…

  5. Compensatory Education Product Evaluation: Elementary and Secondary Programs 1991-1992.

    ERIC Educational Resources Information Center

    Saginaw Public Schools, MI. Dept. of Evaluation Services.

    An evaluation was done of compensatory educational programs in reading and mathematics in the Saginaw (Michigan) School District. The elementary Compensatory Education (CE) program is both a push-in format (grades 1 and 2) and a pull-out format (periodically taking students out of regular classrooms) that serves 2,045 students in grades 1 through…

  6. Impact of Compensatory Intervention in 6- to 18-Month-Old Babies at Risk of Motor Development Delays

    ERIC Educational Resources Information Center

    Müller, Alessandra Bombarda; Saccani, Raquel; Valentini, Nadia Cristina

    2017-01-01

    Purpose: Research indicates that delayed motor development observed in the first years of life can be prevented through compensatory intervention programmes that provide proper care during this critical period of child development. Method: This study analysed the impact of a 12-week compensatory motor intervention programme on 32 babies with…

  7. College Admissions and Academic Ethic: How Context-Specific Evaluation within a Science-Based Compensatory Program Benefits African American Students

    ERIC Educational Resources Information Center

    Wooten, Melissa E.

    2016-01-01

    This study investigates how the college readiness of participants in a compensatory program designed to facilitate interest in science and engineering was determined. Archival data were used to qualitatively analyze the performance reports of 205 student participants during the compensatory program's first 5 years. Findings indicate participants…

  8. Compensatory Programs in Mexico to Reduce the Educational Gap

    ERIC Educational Resources Information Center

    Canales Rodriguez, Emma Laticia; Moreno Olivos, Tiburcio

    2012-01-01

    In this paper we approach the issue of compensatory education programs to reduce the backlog in basic education. We address the population living in rural areas, because the Compensatory Programs (CPs) are aimed at them. The presentation is divided into three parts. The first section presents an approach to basic education in Mexico, the second…

  9. [Orophagyngeal Dysphagia in Older Persons - Evaluation and Therapeutic Options].

    PubMed

    Wirth, Rainer; Lueg, Gero; Dziewas, Rainer

    2018-02-01

    The prevalence of oropharyngeal dysphagia in older persons is high. Because it is frequently undetected, screening tests should be applied in risk groups. If the screening test is positive or typical risk factors are present, an instrumental assessment should be utilized. Objective diagnostic tools such as endoscopic evaluation and videofluoroscopy allow the description of the individual dysphagia pattern, which is the basis for an individualized treatment. The endoscopic evaluation of swallowing is increasingly used because it includes several advantages. Potential therapeutic strategies are multifaceted. The evidence for the effectiveness of adaptive, compensatory and rehabilitative strategies is growing, supporting the evolution of dysphagia therapy to an evidence based treatment. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Molecular evolution of the vertebrate mechanosensory cell and ear.

    PubMed

    Fritzsch, Bernd; Beisel, Kirk W; Pauley, Sarah; Soukup, Garrett

    2007-01-01

    The molecular basis of mechanosensation, mechanosensory cell development and mechanosensory organ development is reviewed with an emphasis on its evolution. In contrast to eye evolution and development, which apparently modified a genetic program through intercalation of genes between the master control genes on the top (Pax6, Eya1, Six1) of the hierarchy and the structural genes (rhodopsin) at the bottom, the as yet molecularly unknown mechanosensory channel precludes such a firm conclusion for mechanosensors. However, recent years have seen the identification of several structural genes which are involved in mechanosensory tethering and several transcription factors controlling mechanosensory cell and organ development; these warrant the interpretation of available data in very much the same fashion as for eye evolution: molecular homology combined with potential morphological parallelism. This assertion of molecular homology is strongly supported by recent findings of a highly conserved set of microRNAs that appear to be associated with mechanosensory cell development across phyla. The conservation of transcription factors and their regulators fits very well to the known or presumed mechanosensory specializations which can be mostly grouped as variations of a common cellular theme. Given the widespread distribution of the molecular ability to form mechanosensory cells, it comes as no surprise that structurally different mechanosensory organs evolved in different phyla, presenting a variation of a common theme specified by a conserved set of transcription factors in their cellular development. Within vertebrates and arthropods, some mechanosensory organs evolved into auditory organs, greatly increasing sensitivity to sound through modifications of accessory structures to direct sound to the specific sensory epithelia. However, while great attention has been paid to the evolution of these accessory structures in vertebrate fossils, comparatively less attention has been spent on the evolution of the inner ear and the central auditory system. Recent advances in our molecular understanding of ear and brain development provide novel avenues to this neglected aspect of auditory neurosensory evolution.

  11. Evolution of Cost-Free Resistance under Fluctuating Drug Selection in Pseudomonas aeruginosa

    PubMed Central

    McCloskey, Nicholas; Hinz, Aaron J.; Dettman, Jeremy; Kassen, Rees

    2017-01-01

    ABSTRACT Antibiotic resistance evolves rapidly in response to drug selection, but it can also persist at appreciable levels even after the removal of the antibiotic. This suggests that many resistant strains can both be resistant and have high fitness in the absence of antibiotics. To explore the conditions under which high-fitness, resistant strains evolve and the genetic changes responsible, we used a combination of experimental evolution and whole-genome sequencing to track the acquisition of ciprofloxacin resistance in the opportunistic pathogen Pseudomonas aeruginosa under conditions of constant and fluctuating antibiotic delivery patterns. We found that high-fitness, resistant strains evolved readily under fluctuating but not constant antibiotic conditions and that their evolution was underlain by a trade-off between resistance and fitness. Whole-genome sequencing of evolved isolates revealed that resistance was gained through mutations in known resistance genes and that second-site mutations generally compensated for costs associated with resistance in the fluctuating treatment, leading to the evolution of cost-free resistance. Our results suggest that current therapies involving intermittent administration of antibiotics are contributing to the maintenance of antibiotic resistance at high levels in clinical settings. IMPORTANCE Antibiotic resistance is a global problem that greatly impacts human health. How resistance persists, even in the absence of antibiotic treatment, is thus a public health problem of utmost importance. In this study, we explored the antibiotic treatment conditions under which cost-free resistance arises, using experimental evolution of the bacterium Pseudomonas aeruginosa and the quinolone antibiotic ciprofloxacin. We found that intermittent antibiotic treatment led to the evolution of cost-free resistance and demonstrate that compensatory evolution is the mechanism responsible for cost-free resistance. Our results suggest that discontinuous administration of antibiotic may be contributing to the high levels of antibiotic resistance currently found worldwide. PMID:28744479

  12. Hybrid incompatibility arises in a sequence-based bioenergetic model of transcription factor binding.

    PubMed

    Tulchinsky, Alexander Y; Johnson, Norman A; Watt, Ward B; Porter, Adam H

    2014-11-01

    Postzygotic isolation between incipient species results from the accumulation of incompatibilities that arise as a consequence of genetic divergence. When phenotypes are determined by regulatory interactions, hybrid incompatibility can evolve even as a consequence of parallel adaptation in parental populations because interacting genes can produce the same phenotype through incompatible allelic combinations. We explore the evolutionary conditions that promote and constrain hybrid incompatibility in regulatory networks using a bioenergetic model (combining thermodynamics and kinetics) of transcriptional regulation, considering the bioenergetic basis of molecular interactions between transcription factors (TFs) and their binding sites. The bioenergetic parameters consider the free energy of formation of the bond between the TF and its binding site and the availability of TFs in the intracellular environment. Together these determine fractional occupancy of the TF on the promoter site, the degree of subsequent gene expression and in diploids, and the degree of dominance among allelic interactions. This results in a sigmoid genotype-phenotype map and fitness landscape, with the details of the shape determining the degree of bioenergetic evolutionary constraint on hybrid incompatibility. Using individual-based simulations, we subjected two allopatric populations to parallel directional or stabilizing selection. Misregulation of hybrid gene expression occurred under either type of selection, although it evolved faster under directional selection. Under directional selection, the extent of hybrid incompatibility increased with the slope of the genotype-phenotype map near the derived parental expression level. Under stabilizing selection, hybrid incompatibility arose from compensatory mutations and was greater when the bioenergetic properties of the interaction caused the space of nearly neutral genotypes around the stable expression level to be wide. F2's showed higher hybrid incompatibility than F1's to the extent that the bioenergetic properties favored dominant regulatory interactions. The present model is a mechanistically explicit case of the Bateson-Dobzhansky-Muller model, connecting environmental selective pressure to hybrid incompatibility through the molecular mechanism of regulatory divergence. The bioenergetic parameters that determine expression represent measurable properties of transcriptional regulation, providing a predictive framework for empirical studies of how phenotypic evolution results in epistatic incompatibility at the molecular level in hybrids. Copyright © 2014 by the Genetics Society of America.

  13. Molecular microenvironments: Solvent interactions with nucleic acid bases and ions

    NASA Technical Reports Server (NTRS)

    Macelroy, R. D.; Pohorille, A.

    1986-01-01

    The possibility of reconstructing plausible sequences of events in prebiotic molecular evolution is limited by the lack of fossil remains. However, with hindsight, one goal of molecular evolution was obvious: the development of molecular systems that became constituents of living systems. By understanding the interactions among molecules that are likely to have been present in the prebiotic environment, and that could have served as components in protobiotic molecular systems, plausible evolutionary sequences can be suggested. When stable aggregations of molecules form, a net decrease in free energy is observed in the system. Such changes occur when solvent molecules interact among themselves, as well as when they interact with organic species. A significant decrease in free energy, in systems of solvent and organic molecules, is due to entropy changes in the solvent. Entropy-driven interactioins played a major role in the organization of prebiotic systems, and understanding the energetics of them is essential to understanding molecular evolution.

  14. Chemomimesis and Molecular Darwinism in Action: From Abiotic Generation of Nucleobases to Nucleosides and RNA.

    PubMed

    Saladino, Raffaele; Šponer, Judit E; Šponer, Jiří; Costanzo, Giovanna; Pino, Samanta; Di Mauro, Ernesto

    2018-06-20

    Molecular Darwinian evolution is an intrinsic property of reacting pools of molecules resulting in the adaptation of the system to changing conditions. It has no a priori aim. From the point of view of the origin of life, Darwinian selection behavior, when spontaneously emerging in the ensembles of molecules composing prebiotic pools, initiates subsequent evolution of increasingly complex and innovative chemical information. On the conservation side, it is a posteriori observed that numerous biological processes are based on prebiotically promptly made compounds, as proposed by the concept of Chemomimesis. Molecular Darwinian evolution and Chemomimesis are principles acting in balanced cooperation in the frame of Systems Chemistry. The one-pot synthesis of nucleosides in radical chemistry conditions is possibly a telling example of the operation of these principles. Other indications of similar cases of molecular evolution can be found among biogenic processes.

  15. Parasitic plants have increased rates of molecular evolution across all three genomes

    PubMed Central

    2013-01-01

    Background Theoretical models and experimental evidence suggest that rates of molecular evolution could be raised in parasitic organisms compared to non-parasitic taxa. Parasitic plants provide an ideal test for these predictions, as there are at least a dozen independent origins of the parasitic lifestyle in angiosperms. Studies of a number of parasitic plant lineages have suggested faster rates of molecular evolution, but the results of some studies have been mixed. Comparative analysis of all parasitic plant lineages, including sequences from all three genomes, is needed to examine the generality of the relationship between rates of molecular evolution and parasitism in plants. Results We analysed DNA sequence data from the mitochondrial, nuclear and chloroplast genomes for 12 independent evolutionary origins of parasitism in angiosperms. We demonstrated that parasitic lineages have a faster rate of molecular evolution than their non-parasitic relatives in sequences for all three genomes, for both synonymous and nonsynonymous substitutions. Conclusions Our results prove that raised rates of molecular evolution are a general feature of parasitic plants, not confined to a few taxa or specific genes. We discuss possible causes for this relationship, including increased positive selection associated with host-parasite arms races, relaxed selection, reduced population size or repeated bottlenecks, increased mutation rates, and indirect causal links with generation time and body size. We find no evidence that faster rates are due to smaller effective populations sizes or changes in selection pressure. Instead, our results suggest that parasitic plants have a higher mutation rate than their close non-parasitic relatives. This may be due to a direct connection, where some aspect of the parasitic lifestyle drives the evolution of raised mutation rates. Alternatively, this pattern may be driven by an indirect connection between rates and parasitism: for example, parasitic plants tend to be smaller than their non-parasitic relatives, which may result in more cell generations per year, thus a higher rate of mutations arising from DNA copy errors per unit time. Demonstration that adoption of a parasitic lifestyle influences the rate of genomic evolution is relevant to attempts to infer molecular phylogenies of parasitic plants and to estimate their evolutionary divergence times using sequence data. PMID:23782527

  16. Parasitic plants have increased rates of molecular evolution across all three genomes.

    PubMed

    Bromham, Lindell; Cowman, Peter F; Lanfear, Robert

    2013-06-19

    Theoretical models and experimental evidence suggest that rates of molecular evolution could be raised in parasitic organisms compared to non-parasitic taxa. Parasitic plants provide an ideal test for these predictions, as there are at least a dozen independent origins of the parasitic lifestyle in angiosperms. Studies of a number of parasitic plant lineages have suggested faster rates of molecular evolution, but the results of some studies have been mixed. Comparative analysis of all parasitic plant lineages, including sequences from all three genomes, is needed to examine the generality of the relationship between rates of molecular evolution and parasitism in plants. We analysed DNA sequence data from the mitochondrial, nuclear and chloroplast genomes for 12 independent evolutionary origins of parasitism in angiosperms. We demonstrated that parasitic lineages have a faster rate of molecular evolution than their non-parasitic relatives in sequences for all three genomes, for both synonymous and nonsynonymous substitutions. Our results prove that raised rates of molecular evolution are a general feature of parasitic plants, not confined to a few taxa or specific genes. We discuss possible causes for this relationship, including increased positive selection associated with host-parasite arms races, relaxed selection, reduced population size or repeated bottlenecks, increased mutation rates, and indirect causal links with generation time and body size. We find no evidence that faster rates are due to smaller effective populations sizes or changes in selection pressure. Instead, our results suggest that parasitic plants have a higher mutation rate than their close non-parasitic relatives. This may be due to a direct connection, where some aspect of the parasitic lifestyle drives the evolution of raised mutation rates. Alternatively, this pattern may be driven by an indirect connection between rates and parasitism: for example, parasitic plants tend to be smaller than their non-parasitic relatives, which may result in more cell generations per year, thus a higher rate of mutations arising from DNA copy errors per unit time. Demonstration that adoption of a parasitic lifestyle influences the rate of genomic evolution is relevant to attempts to infer molecular phylogenies of parasitic plants and to estimate their evolutionary divergence times using sequence data.

  17. From "Cultural Deprivation" to Cultural Capital: The Roots and Continued Relevance of Compensatory Education

    ERIC Educational Resources Information Center

    Spencer, John

    2012-01-01

    This article is a case study of compensatory education as it was developed and implemented by an innovative urban school principal in the early 1960s. I argue that while the compensatory education movement was often marred by pejorative-sounding language and inegalitarian ideas, especially as it was shaped and expanded by policy makers and…

  18. What Is Compensatory Pedagogy Trying to Compensate for? Compensatory Strategies and the Ethnic "Other"

    ERIC Educational Resources Information Center

    Moller, Asa

    2012-01-01

    Compensatory pedagogy is in theory a strategy used to manage social and cultural diversity (Sleeter, 2007) by providing extra resources or special treatment for so-called deprived groups. A problem with this particular kind of approach to social and cultural diversity is that it lacks critical awareness of the way social differences (i.e. race,…

  19. Compensatory dynamics stabilize aggregate community properties in response to multiple types of perturbations.

    PubMed

    Brown, Bryan L; Downing, Amy L; Leibold, Mathew A

    2016-08-01

    Compensatory dynamics are an important suite of mechanisms that can stabilize community and ecosystem attributes in systems subject to environmental fluctuations. However, few experimental investigations of compensatory dynamics have addressed these mechanisms in systems of real-world complexity, and existing evidence relies heavily on correlative analyses, retrospective examination, and experiments in simple systems. We investigated the potential for compensatory dynamics to stabilize plankton communities in plankton mesocosm systems of real-world complexity. We employed four types of perturbations including two types of nutrient pulses, shading, and acidification. To quantify how communities responded to these perturbations, we used a measure of community-wide synchrony combined with spectral analysis that allowed us to assess timescale-specific community dynamics, for example, whether dynamics were synchronous at some timescales but compensatory at others. The 150-d experiment produced 32-point time series of all zooplankton taxa in the mesocosms. We then used those time series to evaluate total zooplankton biomass as an aggregate property and to evaluate community dynamics. For three of our four perturbation types, total zooplankton biomass was significantly less variable in systems with environmental variation than in constant environments. For the same three perturbation types, community-wide synchrony was much lower in fluctuating environments than in the constant environment, particularly at longer timescales (periods ≈ 60 d). Additionally, there were strong negative correlations between population temporal variances and the level of community-wide synchrony. Taken together, these results strongly imply that compensatory interactions between species stabilized total biomass in response to perturbations. Diversity did not differ significantly across either treatments or perturbation types, thus ruling out several classes of mechanisms driven by changes in diversity. We also used several pieces of secondary evidence to evaluate the particular mechanism behind compensatory responses since a wide variety of mechanisms are hypothesized to produce compensatory dynamics. We concluded that fluctuation dependent endogenous cycles that occur as a consequence of consumer-resource interactions in competitive communities were the most likely explanation for the compensatory dynamics observed in our experiment. As with our previous work, scale-dependent dynamics were also a key to understanding compensatory dynamics in these experimental communities. © 2016 by the Ecological Society of America.

  20. Star formation in evolving molecular clouds

    NASA Astrophysics Data System (ADS)

    Völschow, M.; Banerjee, R.; Körtgen, B.

    2017-09-01

    Molecular clouds are the principle stellar nurseries of our universe; they thus remain a focus of both observational and theoretical studies. From observations, some of the key properties of molecular clouds are well known but many questions regarding their evolution and star formation activity remain open. While numerical simulations feature a large number and complexity of involved physical processes, this plethora of effects may hide the fundamentals that determine the evolution of molecular clouds and enable the formation of stars. Purely analytical models, on the other hand, tend to suffer from rough approximations or a lack of completeness, limiting their predictive power. In this paper, we present a model that incorporates central concepts of astrophysics as well as reliable results from recent simulations of molecular clouds and their evolutionary paths. Based on that, we construct a self-consistent semi-analytical framework that describes the formation, evolution, and star formation activity of molecular clouds, including a number of feedback effects to account for the complex processes inside those objects. The final equation system is solved numerically but at much lower computational expense than, for example, hydrodynamical descriptions of comparable systems. The model presented in this paper agrees well with a broad range of observational results, showing that molecular cloud evolution can be understood as an interplay between accretion, global collapse, star formation, and stellar feedback.

  1. Experimental evolution of protein–protein interaction networks

    PubMed Central

    Kaçar, Betül; Gaucher, Eric A.

    2013-01-01

    The modern synthesis of evolutionary theory and genetics has enabled us to discover underlying molecular mechanisms of organismal evolution. We know that in order to maximize an organism's fitness in a particular environment, individual interactions among components of protein and nucleic acid networks need to be optimized by natural selection, or sometimes through random processes, as the organism responds to changes and/or challenges in the environment. Despite the significant role of molecular networks in determining an organism's adaptation to its environment, we still do not know how such inter- and intra-molecular interactions within networks change over time and contribute to an organism's evolvability while maintaining overall network functions. One way to address this challenge is to identify connections between molecular networks and their host organisms, to manipulate these connections, and then attempt to understand how such perturbations influence molecular dynamics of the network and thus influence evolutionary paths and organismal fitness. In the present review, we discuss how integrating evolutionary history with experimental systems that combine tools drawn from molecular evolution, synthetic biology and biochemistry allow us to identify the underlying mechanisms of organismal evolution, particularly from the perspective of protein interaction networks. PMID:23849056

  2. Molecular Clock of Neutral Mutations in a Fitness-Increasing Evolutionary Process

    PubMed Central

    Iijima, Leo; Suzuki, Shingo; Hashimoto, Tomomi; Oyake, Ayana; Kobayashi, Hisaka; Someya, Yuki; Narisawa, Dai; Yomo, Tetsuya

    2015-01-01

    The molecular clock of neutral mutations, which represents linear mutation fixation over generations, is theoretically explained by genetic drift in fitness-steady evolution or hitchhiking in adaptive evolution. The present study is the first experimental demonstration for the molecular clock of neutral mutations in a fitness-increasing evolutionary process. The dynamics of genome mutation fixation in the thermal adaptive evolution of Escherichia coli were evaluated in a prolonged evolution experiment in duplicated lineages. The cells from the continuously fitness-increasing evolutionary process were subjected to genome sequencing and analyzed at both the population and single-colony levels. Although the dynamics of genome mutation fixation were complicated by the combination of the stochastic appearance of adaptive mutations and clonal interference, the mutation fixation in the population was simply linear over generations. Each genome in the population accumulated 1.6 synonymous and 3.1 non-synonymous neutral mutations, on average, by the spontaneous mutation accumulation rate, while only a single genome in the population occasionally acquired an adaptive mutation. The neutral mutations that preexisted on the single genome hitchhiked on the domination of the adaptive mutation. The successive fixation processes of the 128 mutations demonstrated that hitchhiking and not genetic drift were responsible for the coincidence of the spontaneous mutation accumulation rate in the genome with the fixation rate of neutral mutations in the population. The molecular clock of neutral mutations to the fitness-increasing evolution suggests that the numerous neutral mutations observed in molecular phylogenetic trees may not always have been fixed in fitness-steady evolution but in adaptive evolution. PMID:26177190

  3. Molecular Clock of Neutral Mutations in a Fitness-Increasing Evolutionary Process.

    PubMed

    Kishimoto, Toshihiko; Ying, Bei-Wen; Tsuru, Saburo; Iijima, Leo; Suzuki, Shingo; Hashimoto, Tomomi; Oyake, Ayana; Kobayashi, Hisaka; Someya, Yuki; Narisawa, Dai; Yomo, Tetsuya

    2015-07-01

    The molecular clock of neutral mutations, which represents linear mutation fixation over generations, is theoretically explained by genetic drift in fitness-steady evolution or hitchhiking in adaptive evolution. The present study is the first experimental demonstration for the molecular clock of neutral mutations in a fitness-increasing evolutionary process. The dynamics of genome mutation fixation in the thermal adaptive evolution of Escherichia coli were evaluated in a prolonged evolution experiment in duplicated lineages. The cells from the continuously fitness-increasing evolutionary process were subjected to genome sequencing and analyzed at both the population and single-colony levels. Although the dynamics of genome mutation fixation were complicated by the combination of the stochastic appearance of adaptive mutations and clonal interference, the mutation fixation in the population was simply linear over generations. Each genome in the population accumulated 1.6 synonymous and 3.1 non-synonymous neutral mutations, on average, by the spontaneous mutation accumulation rate, while only a single genome in the population occasionally acquired an adaptive mutation. The neutral mutations that preexisted on the single genome hitchhiked on the domination of the adaptive mutation. The successive fixation processes of the 128 mutations demonstrated that hitchhiking and not genetic drift were responsible for the coincidence of the spontaneous mutation accumulation rate in the genome with the fixation rate of neutral mutations in the population. The molecular clock of neutral mutations to the fitness-increasing evolution suggests that the numerous neutral mutations observed in molecular phylogenetic trees may not always have been fixed in fitness-steady evolution but in adaptive evolution.

  4. Design and analysis of an original powered foot clearance creator mechanism for walking in patients with spinal cord injury.

    PubMed

    Maleki, Maryam; Badri, Samaneh; Shayestehepour, Hamed; Arazpour, Mokhtar; Farahmand, Farzam; Mousavi, Mohamad Ebrahim; Abdolahi, Ehsan; Farkhondeh, Hasan; Head, John S; Golchin, Navid; Mardani, Mohammad Ali

    2018-03-12

    The aim of this study was to assess the performance of an original powered foot clearance creator (PFCC) mechanism worn in conjunction with an isocentric reciprocal gait orthosis (IRGO) and evaluate its effect on trunk compensatory movements and spatiotemporal parameters in nine healthy subjects. A PFCC motorized mechanism was designed that incorporated twin sole plates, the movements of which enabled increased toe to floor clearance during swing phase. A prototype was constructed in combination with an IRGO, and hence was re-named as an IRGO-PFCC orthosis. The effects of IRGO-PFCC usage on the spatiotemporal parameters and trunk compensatory movements during walking were then analyzed under two conditions, firstly with the PFCC 'active' i.e., with the motorized device functioning, and secondly inactive, where floor clearance was standard. Ambulating with IRGO-PFCC orthosis resulted in reduction in the spatiotemporal parameters of gait (speed of walking, cadence and stride length) in nine healthy subjects. Walking with IRGO-PFCC orthosis led to significant differences in lateral (p = .007) and vertical (p = .008) trunk compensatory movements. In other words, through using IRGO-PFCC orthosis, the lateral and vertical trunk compensatory movements decreased by 51.32% and 42.7%, respectively. An adapted PFCC mechanism, with a relatively small motor and power supply could effectively increase toe to floor clearance during swing phase and thereby decrease trunk compensatory motions and potentially improve energy consumption. Implications for rehabilitations •The High rejection rates of reciprocal gait orthoses are related to the increasing in energy expenditure and burden loads on the upper limb joints during walking following trunk compensatory movements.•An original powered foot clearance creator mechanism was designed and constructed to assisting floor clearance capability and reduce trunk compensatory movements in subjects with spinal cord injury during swing phase of gait.•This original powered foot clearance creator mechanism by using moveable soleplates and motorized actuation could decrease the trunk compensatory motions during the ambulation of nine healthy subjects.•More experiments are needed to investigate this mechanism on trunk compensatory movements of SCI subjects.

  5. Evolutionary landscape of the Mycobacterium tuberculosis complex from the viewpoint of PhoPR: implications for virulence regulation and application to vaccine development.

    PubMed

    Broset, Esther; Martín, Carlos; Gonzalo-Asensio, Jesús

    2015-10-20

    Different members of the Mycobacterium genus have evolved to cause tuberculosis in diverse human populations and in a variety of animal species. Our cumulative knowledge of mycobacterial genomes indicates that mutations in the PhoPR two-component virulence system were acquired not only during the natural evolution of mycobacterial species but also during in vitro subculture, which has given rise to the attenuated reference strain H37Ra or to different daughter strains of Mycobacterium bovis BCG. PhoPR is a well-known regulator of pathogenic phenotypes, including secretion of the virulence factor ESAT-6, biosynthesis of acyltrehalose-based lipids, and modulation of antigen export, in members of the Mycobacterium tuberculosis complex (MTBC). Evolutionarily conserved polymorphisms in PhoPR from Mycobacterium africanum, M. bovis, or M. tuberculosis H37Ra result in loss of functional phenotypes. Interestingly, some members of the MTBC have acquired compensatory mutations to counteract these polymorphisms and, probably, to maintain their pathogenic potential. Some of these compensatory mutations include the insertion of the IS6110 element upstream from phoPR in a particular M. bovis strain that is able to transmit between humans or polymorphisms in M. africanum and M. bovis that affect the regulatory region of the espACD operon, allowing PhoPR-independent ESAT-6 secretion. This review highlights the increasing knowledge of the significance of PhoPR in the evolution of the MTBC and its potential application in the construction of new attenuated vaccines based on phoPR inactivation. In this context, the live attenuated vaccine MTBVAC, based on a phoP fadD26 deletion mutant of M. tuberculosis, is the first vaccine of this kind to successfully enter into clinical development, representing a historic milestone in the field of human vaccinology. Copyright © 2015 Broset et al.

  6. Evolutionary Landscape of the Mycobacterium tuberculosis Complex from the Viewpoint of PhoPR: Implications for Virulence Regulation and Application to Vaccine Development

    PubMed Central

    Broset, Esther

    2015-01-01

    ABSTRACT Different members of the Mycobacterium genus have evolved to cause tuberculosis in diverse human populations and in a variety of animal species. Our cumulative knowledge of mycobacterial genomes indicates that mutations in the PhoPR two-component virulence system were acquired not only during the natural evolution of mycobacterial species but also during in vitro subculture, which has given rise to the attenuated reference strain H37Ra or to different daughter strains of Mycobacterium bovis BCG. PhoPR is a well-known regulator of pathogenic phenotypes, including secretion of the virulence factor ESAT-6, biosynthesis of acyltrehalose-based lipids, and modulation of antigen export, in members of the Mycobacterium tuberculosis complex (MTBC). Evolutionarily conserved polymorphisms in PhoPR from Mycobacterium africanum, M. bovis, or M. tuberculosis H37Ra result in loss of functional phenotypes. Interestingly, some members of the MTBC have acquired compensatory mutations to counteract these polymorphisms and, probably, to maintain their pathogenic potential. Some of these compensatory mutations include the insertion of the IS6110 element upstream from phoPR in a particular M. bovis strain that is able to transmit between humans or polymorphisms in M. africanum and M. bovis that affect the regulatory region of the espACD operon, allowing PhoPR-independent ESAT-6 secretion. This review highlights the increasing knowledge of the significance of PhoPR in the evolution of the MTBC and its potential application in the construction of new attenuated vaccines based on phoPR inactivation. In this context, the live attenuated vaccine MTBVAC, based on a phoP fadD26 deletion mutant of M. tuberculosis, is the first vaccine of this kind to successfully enter into clinical development, representing a historic milestone in the field of human vaccinology. PMID:26489860

  7. On the Overdispersed Molecular Clock

    PubMed Central

    Takahata, Naoyuki

    1987-01-01

    Rates of molecular evolution at some loci are more irregular than described by simple Poisson processes. Three situations under which molecular evolution would not follow simple Poisson processes are reevaluated from the viewpoint of the neutrality hypothesis: (i) concomitant or multiple substitutions in a gene, (ii) fluctuating substitution rates in time caused by coupled effects of deleterious mutations and bottlenecks, and (iii) changes in the degree of selective constraints against a gene (neutral space) caused by successive substitutions. The common underlying assumption that these causes are lineage nonspecific excludes the case where mutation rates themselves change systematically among lineages or taxonomic groups, and severely limits the extent of variation in the number of substitutions among lineages. Even under this stringent condition, however, the third hypothesis, the fluctuating neutral space model, can generate fairly large variation. This is described by a time-dependent renewal process, which does not exhibit any episodic nature of molecular evolution. It is argued that the observed elevated variances in the number of nucleotide or amino acid substitutions do not immediately call for positive Darwinian selection in molecular evolution. PMID:3596230

  8. Advances on molecular mechanism of the adaptive evolution of Chiroptera (bats).

    PubMed

    Yunpeng, Liang; Li, Yu

    2015-01-01

    As the second biggest animal group in mammals, Chiroptera (bats) demonstrates many unique adaptive features in terms of flight, echolocation, auditory acuity, feeding habit, hibernation and immune defense, providing an excellent system for understanding the molecular basis of how organisms adapt to the living environments encountered. In this review, we summarize the researches on the molecular mechanism of the adaptive evolution of Chiroptera, especially the recent researches at the genome levels, suggesting a far more complex evolutionary pattern and functional diversity than previously thought. In the future, along with the increasing numbers of Chiroptera species genomes available, new evolutionary patterns and functional divergence will be revealed, which can promote the further understanding of this animal group and the molecular mechanism of adaptive evolution.

  9. Insight into multidrug-resistant Beijing genotype Mycobacterium tuberculosis isolates in Myanmar.

    PubMed

    San, Lai Lai; Aye, Khin Saw; Oo, Nan Aye Thida; Shwe, Mu Mu; Fukushima, Yukari; Gordon, Stephen V; Suzuki, Yasuhiko; Nakajima, Chie

    2018-06-21

    Myanmar is a WHO high tuberculosis (TB) burden country with a high multidrug-resistant (MDR)-TB burden. Significantly a high prevalence of the Beijing genotype of Mycobacterium tuberculosis (MTB) among MDR-MTB has been reported previously. To explore whether an association exists between the prevalence of the Beijing MTB genotype and MDR-TB in Myanmar, we performed detailed genetic characterization of TB clinical isolates. A total of 265 MDR-MTB clinical isolates collected in 2010 and 2012 were subjected to spoligotyping, mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) analysis, SNP typing and drug resistance-associated gene sequencing including rpoC to detect potential compensatory evolution. Of the total MDR-MTB isolates, 79.2% (210/265) were of the Beijing genotype, the majority of which were the "modern" subtype. Beijing genotype isolates were differentiated by 15-loci MIRU-VNTR and a high clustering rate (53.0%) was observed in the modern subtype. These MIRU-VNTR patterns were similar to Beijing genotype clones spreading across Russia and Central Asia. High prevalence of katG Ser315Thr, and genetic evidence of XDR and pre-XDR and compensatory mutations in rpoC were observed among clustered isolates. MDR-MTB strains of the Beijing genotype might be spreading in Myanmar and present a major challenge to TB control in this country. Copyright © 2018. Published by Elsevier Ltd.

  10. Compensatory Hypertrophy Induced by Ventricular Cardiomyocyte Specific COX-2 Expression in Mice

    PubMed Central

    Streicher, John M.; Kamei, Kenichiro; Ishikawa, Tomo-o; Herschman, Harvey; Wang, Yibin

    2010-01-01

    Cyclooxygenase-2 (COX-2) is an important mediator of inflammation in stress and disease states. Recent attention has focused on the role of COX-2 in human heart failure and diseases, due to the finding that highly specific COX-2 inhibitors (i.e. Vioxx) increased the risk of myocardial infarction and stroke in chronic users. However, the specific impact of COX-2 expression in the intact heart remains to be determined. We report here the development of a transgenic mouse model, using a loxP-Cre approach, that displays robust COX-2 overexpression and subsequent prostaglandin synthesis specifically in ventricular myocytes. Histological, functional and molecular analyses showed that ventricular myocyte specific COX-2 overexpression led to cardiac hypertrophy and fetal gene marker activation, but with preserved cardiac function. Therefore, specific induction of COX-2 and prostaglandin in vivo is sufficient to induce compensated hypertrophy and molecular remodeling. PMID:20170663

  11. Fast and ultrafast endocytosis.

    PubMed

    Watanabe, Shigeki; Boucrot, Emmanuel

    2017-08-01

    Clathrin-mediated endocytosis (CME) is the main endocytic pathway supporting housekeeping functions in cells. However, CME may be too slow to internalize proteins from the cell surface during certain physiological processes such as reaction to stress hormones ('fight-or-flight' reaction), chemotaxis or compensatory endocytosis following exocytosis of synaptic vesicles or hormone-containing vesicles. These processes take place on a millisecond to second timescale and thus require very rapid cellular reaction to prevent overstimulation or exhaustion of the response. There are several fast endocytic processes identified so far: macropinocytosis, activity-dependent bulk endocytosis (ABDE), fast-endophilin-mediated endocytosis (FEME), kiss-and-run and ultrafast endocytosis. All are clathrin-independent and are not constitutively active but may use different molecular mechanisms to rapidly remove receptors and proteins from the cell surface. Here, we review our current understanding of fast and ultrafast endocytosis, their functions, and molecular mechanisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Advances in Flying Qualities

    DTIC Science & Technology

    1988-05-01

    compensatory operations as a dual-mods control -- a form where the control exerted is Initiated and largely accomplished by the precognitive action and then...function. Fig. 3.2 Compensatory control structure for 4-7 precognitive operation occur in a "dual- quality criteria one is referred to mode" control... precognitive action Tesil itatieet rpoas f and then completed with compensatory error- mil quent ei to eure a reduction operations (Ref. 11). certary eqe mso

  13. Expanded Level of Sympathetic Chain Removal Does Not Increase Incidence or Severity of Compensatory Hyperhidrosis Following Endoscopic Thoracic Sympathectomy

    PubMed Central

    Gunn, Tyler M.; Davis, Diane M.; Speicher, James E.; Rossi, Nicholas P.; Parekh, Kalpaj R.; Lynch, William R.; Iannettoni, Mark D.

    2015-01-01

    Objective Compensatory hyperhidrosis is a common devastating adverse effect following endoscopic thoracic sympathectomy for patients undergoing surgical treatment of primary hyperhidrosis. We sought to determine if there was a correlation in our patient population between the level and extent of sympathetic chain resection and the subsequent development of compensatory hyperhidrosis. Methods All patients undergoing endoscopic thoracic sympathectomy in the T2-3, T2-4, T2-5, or T2-6 levels for palmar or axillary hyperhidrosis at the University of Iowa Hospital and Clinics (n=97) between January 2004 and January 2013 were retrospectively reviewed. Results Differences in preoperative patient characteristics were not statistically significant between patients receiving either T2-3, T2-4, T2-5, or T2-6 level resections. Of the ninety-seven patients included in this study, twenty-eight patients (29%) experienced transient compensatory hyperhidrosis and four patients (4%) complained of severe compensatory hyperhidrosis and required further treatment. There were no operative mortalities and morbidity was similar amongst the groups. Conclusions Most patients had successful outcomes after undergoing extensive resection without change in incidence of compensatory hyperhidrosis. Therefore, we recommend performing a complete and adequate resection for relief of symptoms in patients with primary hyperhidrosis. PMID:25131173

  14. Investigation of compensatory postures with videofluoromanometry in dysphagia patients

    PubMed Central

    Solazzo, Antonio; Monaco, Luigi; Del Vecchio, Lucia; Tamburrini, Stefania; Iacobellis, Francesca; Berritto, Daniela; Pizza, Nunzia Luisa; Reginelli, Alfonso; Di Martino, Natale; Grassi, Roberto

    2012-01-01

    AIM: To investigate the effectiveness of head compensatory postures to ensure safe oropharyngeal transit. METHODS: A total of 321 dysphagia patients were enrolled and assessed with videofluoromanometry (VFM). The dysphagia patients were classified as follows: safe transit; penetration without aspiration; aspiration before, during or after swallowing; multiple aspirations and no transit. The patients with aspiration or no transit were tested with VFM to determine whether compensatory postures could correct their swallowing disorder. RESULTS: VFM revealed penetration without aspiration in 71 patients (22.1%); aspiration before swallowing in 17 patients (5.3%); aspiration during swallowing in 32 patients (10%); aspiration after swallowing in 21 patients (6.5%); multiple aspirations in six patients (1.9%); no transit in five patients (1.6%); and safe transit in 169 patients (52.6%). Compensatory postures guaranteed a safe transit in 66/75 (88%) patients with aspiration or no transit. A chin-down posture achieved a safe swallow in 42/75 (56%) patients, a head-turned posture in 19/75 (25.3%) and a hyperextended head posture in 5/75 (6.7%). The compensatory postures were not effective in 9/75 (12%) cases. CONCLUSION: VFM allows the speech-language the-rapist to choose the most effective compensatory posture without a trial-and-error process and check the effectiveness of the posture. PMID:22736921

  15. Synchronous dynamics of zooplankton competitors prevail in temperate lake ecosystems.

    PubMed

    Vasseur, David A; Fox, Jeremy W; Gonzalez, Andrew; Adrian, Rita; Beisner, Beatrix E; Helmus, Matthew R; Johnson, Catherine; Kratina, Pavel; Kremer, Colin; de Mazancourt, Claire; Miller, Elizabeth; Nelson, William A; Paterson, Michael; Rusak, James A; Shurin, Jonathan B; Steiner, Christopher F

    2014-08-07

    Although competing species are expected to exhibit compensatory dynamics (negative temporal covariation), empirical work has demonstrated that competitive communities often exhibit synchronous dynamics (positive temporal covariation). This has led to the suggestion that environmental forcing dominates species dynamics; however, synchronous and compensatory dynamics may appear at different length scales and/or at different times, making it challenging to identify their relative importance. We compiled 58 long-term datasets of zooplankton abundance in north-temperate and sub-tropical lakes and used wavelet analysis to quantify general patterns in the times and scales at which synchronous/compensatory dynamics dominated zooplankton communities in different regions and across the entire dataset. Synchronous dynamics were far more prevalent at all scales and times and were ubiquitous at the annual scale. Although we found compensatory dynamics in approximately 14% of all combinations of time period/scale/lake, there were no consistent scales or time periods during which compensatory dynamics were apparent across different regions. Our results suggest that the processes driving compensatory dynamics may be local in their extent, while those generating synchronous dynamics operate at much larger scales. This highlights an important gap in our understanding of the interaction between environmental and biotic forces that structure communities. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  16. The effect of cane use on the compensatory step following posterior perturbations.

    PubMed

    Hall, Courtney D; Jensen, Jody L

    2004-08-01

    The compensatory step is a critical component of the balance response and is impaired in older fallers. The purpose of this research was to examine whether utilization of a cane modified the compensatory step response following external posterior perturbations. Single subject withdrawal design was employed. Single subject statistical analysis--the standard deviation bandwidth-method--supplemented visual analysis of the data. Four older adults (range: 73-83 years) with balance impairment who habitually use a cane completed this study. Subjects received a series of sudden backward pulls that were large enough to elicit compensatory stepping. We examined the following variables both with and without cane use: timing of cane loading relative to step initiation and center of mass acceleration, stability margin, center of mass excursion and velocity, step length and width. No participant loaded the cane prior to initiation of the first compensatory step. There was no effect of cane use on the stability margin, nor was there an effect of cane use on center of mass excursion or velocity, or step length or width. These data suggest that cane use does not necessarily improve balance recovery following an external posterior perturbation when the individual is forced to rely on compensatory stepping. Instead these data suggest that the strongest factor in modifying step characteristics is experience with the perturbation.

  17. Differences in Biases and Compensatory Strategies Across Discipline, Rank, and Gender among University Academics

    PubMed Central

    Giorgini, Vincent; Gibson, Carter; Mecca, Jensen T.; Medeiros, Kelsey E.; Mumford, Michael D.; Connelly, Shane; Devenport, Lynn D.

    2014-01-01

    The study of ethical behavior and ethical decision making is of increasing importance in many fields, and there is a growing literature addressing the issue. However, research examining differences in ethical decision making across fields and levels of experience is limited. In the present study, biases that undermine ethical decision making and compensatory strategies that may aid ethical decision making were identified in a series of interviews with 63 faculty members across six academic fields (e.g. biological sciences, health sciences, social sciences) and three levels of rank (assistant professor, associate professor, and full professor) as well as across gender. The degree to which certain biases and compensatory strategies were used in justifications for responses to ethical situations was compared across fields, level of experience, and gender. Major differences were found across fields for several biases and compensatory strategies, including biases and compensatory strategies related to use of professional field principles and field-specific guidelines. Furthermore, full professors tend to differ greatly from assistant and associate professors on a number of constructs, and there were differences in the consistency with which biases and compensatory strategies were displayed within these various groups. Implications of these findings for ethics training and future research are discussed. PMID:25479960

  18. An exploration of the influence of thinness expectancies and eating pathology on compensatory exercise.

    PubMed

    Garner, Ashton; Davis-Becker, Kendra; Fischer, Sarah

    2014-08-01

    Compensatory exercise (exercise performed in an effort to control weight/shape or in response to caloric intake) and thinness expectancies (beliefs that thinness will improve the overall quality of life) are strongly linked to the development, maintenance, severity, and outcome of eating disorders. There is little literature, however, examining the relationship between compensatory exercise and thinness expectancies. The goal of the current study was to examine whether thinness expectancies contribute significant variance in the endorsement of excessive exercise over and above binge eating, restraint, and shape and weight concerns. A total of 677 undergraduate women (mean age=18.73) completed self-report measures of thinness expectancies and eating disorder symptoms (TREI and EDE-Q). There was a significant association between thinness expectancies and frequency of compensatory exercise behavior. Restraint and subjective binge episodes accounted for significant variance in compensatory exercise. Frequency of objective binge episodes did not, nor did endorsement of thinness expectancies. These findings suggest a potential profile of individuals engaging in compensatory exercise as individuals who actively restrict their diets, feel as if they have binged when they violate those restrictions, and feel the need to excessively exercise to compensate for the subjective binges. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. The evolution of cell types in animals: emerging principles from molecular studies.

    PubMed

    Arendt, Detlev

    2008-11-01

    Cell types are fundamental units of multicellular life but their evolution is obscure. How did the first cell types emerge and become distinct in animal evolution? What were the sets of cell types that existed at important evolutionary nodes that represent eumetazoan or bilaterian ancestors? How did these ancient cell types diversify further during the evolution of organ systems in the descending evolutionary lines? The recent advent of cell type molecular fingerprinting has yielded initial insights into the evolutionary interrelationships of cell types between remote animal phyla and has allowed us to define some first principles of cell type diversification in animal evolution.

  20. Molecular Signatures of Membrane Protein Complexes Underlying Muscular Dystrophy*

    PubMed Central

    Turk, Rolf; Hsiao, Jordy J.; Smits, Melinda M.; Ng, Brandon H.; Pospisil, Tyler C.; Jones, Kayla S.; Campbell, Kevin P.; Wright, Michael E.

    2016-01-01

    Mutations in genes encoding components of the sarcolemmal dystrophin-glycoprotein complex (DGC) are responsible for a large number of muscular dystrophies. As such, molecular dissection of the DGC is expected to both reveal pathological mechanisms, and provides a biological framework for validating new DGC components. Establishment of the molecular composition of plasma-membrane protein complexes has been hampered by a lack of suitable biochemical approaches. Here we present an analytical workflow based upon the principles of protein correlation profiling that has enabled us to model the molecular composition of the DGC in mouse skeletal muscle. We also report our analysis of protein complexes in mice harboring mutations in DGC components. Bioinformatic analyses suggested that cell-adhesion pathways were under the transcriptional control of NFκB in DGC mutant mice, which is a finding that is supported by previous studies that showed NFκB-regulated pathways underlie the pathophysiology of DGC-related muscular dystrophies. Moreover, the bioinformatic analyses suggested that inflammatory and compensatory mechanisms were activated in skeletal muscle of DGC mutant mice. Additionally, this proteomic study provides a molecular framework to refine our understanding of the DGC, identification of protein biomarkers of neuromuscular disease, and pharmacological interrogation of the DGC in adult skeletal muscle https://www.mda.org/disease/congenital-muscular-dystrophy/research. PMID:27099343

  1. The Molecular Basis of Evolution and Disease: A Cold War Alliance.

    PubMed

    Suárez-Díaz, Edna

    2017-03-28

    This paper extends previous arguments against the assumption that the study of variation at the molecular level was instigated with a view to solving an internal conflict between the balance and classical schools of population genetics. It does so by focusing on the intersection of basic research in protein chemistry and the molecular approach to disease with the enactment of global health campaigns during the Cold War period. The paper connects advances in research on protein structure and function as reflected in Christian Anfinsen's The molecular basis of evolution, with a political reading of Emilé Zuckerkandl and Linus Pauling's identification of molecular disease and evolution. Beyond atomic fallout, these advances constituted a rationale for the promotion of genetic surveys of human populations in the Third World, in connection with international health programs. Light is shed not only on the experimental roots of the molecular challenge but on the broader geopolitical context where the rising role of biomedicine and public health (particularly the malaria eradication campaigns) had an impact on evolutionary biology.

  2. Alleles versus mutations: Understanding the evolution of genetic architecture requires a molecular perspective on allelic origins.

    PubMed

    Remington, David L

    2015-12-01

    Perspectives on the role of large-effect quantitative trait loci (QTL) in the evolution of complex traits have shifted back and forth over the past few decades. Different sets of studies have produced contradictory insights on the evolution of genetic architecture. I argue that much of the confusion results from a failure to distinguish mutational and allelic effects, a limitation of using the Fisherian model of adaptive evolution as the lens through which the evolution of adaptive variation is examined. A molecular-based perspective reveals that allelic differences can involve the cumulative effects of many mutations plus intragenic recombination, a model that is supported by extensive empirical evidence. I discuss how different selection regimes could produce very different architectures of allelic effects under a molecular-based model, which may explain conflicting insights on genetic architecture from studies of variation within populations versus between divergently selected populations. I address shortcomings of genome-wide association study (GWAS) practices in light of more suitable models of allelic evolution, and suggest alternate GWAS strategies to generate more valid inferences about genetic architecture. Finally, I discuss how adopting more suitable models of allelic evolution could help redirect research on complex trait evolution toward addressing more meaningful questions in evolutionary biology. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  3. The Sample for the Sustaining Effects Study and Projections of its Characteristic to the National Population. Technical Report No. 1 from the Study of Sustaining Effects of Compensatory Education on Basic Skills.

    ERIC Educational Resources Information Center

    Hoepfner, Ralph; And Others

    Sampling techniques used in "A Study of the Sustaining Effects of Compensatory Education" are described in detail. The Sustaining Effects Study is a large, multi-faceted study of issues related to the compensatory education of elementary school students. Public elementary schools that include grades between one and six are eligible for…

  4. The double-edged sword: How evolution can make or break a live-attenuated virus vaccine

    PubMed Central

    Hanley, Kathryn A.

    2012-01-01

    Even students who reject evolution are often willing to consider cases in which evolutionary biology contributes to, or undermines, biomedical interventions. Moreover the intersection of evolutionary biology and biomedicine is fascinating in its own right. This review offers an overview of the ways in which evolution has impacted the design and deployment of live-attenuated virus vaccines, with subsections that may be useful as lecture material or as the basis for case studies in classes at a variety of levels. Live- attenuated virus vaccines have been modified in ways that restrain their replication in a host, so that infection (vaccination) produces immunity but not disease. Applied evolution, in the form of serial passage in novel host cells, is a “classical” method to generate live-attenuated viruses. However many live-attenuated vaccines exhibit reversion to virulence through back-mutation of attenuating mutations, compensatory mutations elsewhere in the genome, recombination or reassortment, or changes in quasispecies diversity. Additionally the combination of multiple live-attenuated strains may result in competition or facilitation between individual vaccine viruses, resulting in undesirable increases in virulence or decreases in immunogenicity. Genetic engineering informed by evolutionary thinking has led to a number of novel approaches to generate live-attenuated virus vaccines that contain substantial safeguards against reversion to virulence and that ameliorate interference among multiple vaccine strains. Finally, vaccines have the potential to shape the evolution of their wild type counterparts in counter-productive ways; at the extreme vaccine-driven eradication of a virus may create an empty niche that promotes the emergence of new viral pathogens. PMID:22468165

  5. Selective muscle fiber loss and molecular compensation in mitochondrial myopathy due to TK2 deficiency.

    PubMed

    Vilà, Maya R; Villarroya, Joan; García-Arumí, Elena; Castellote, Amparo; Meseguer, Anna; Hirano, Michio; Roig, Manuel

    2008-04-15

    A 12-year-old patient with mitochondrial DNA (mtDNA) depletion syndrome due to TK2 gene mutations has been evaluated serially over the last 10 years. We observed progressive muscle atrophy with selective loss of type 2 muscle fibers and, despite severe depletion of mtDNA, normal activities of respiratory chain (RC) complexes and levels of COX II mitochondrial protein in the remaining muscle fibers. These results indicate that compensatory mechanisms account for the slow progression of the disease. Identification of factors that ameliorate mtDNA depletion may reveal new therapeutic targets for these devastating disorders.

  6. First comparative study of primate morphological and molecular evolutionary rates including muscle data: implications for the tempo and mode of primate and human evolution

    PubMed Central

    Diogo, Rui; Peng, Zuogang; Wood, Bernard

    2013-01-01

    Here we provide the first report about the rates of muscle evolution derived from Bayesian and parsimony cladistic analyses of primate higher-level phylogeny, and compare these rates with published rates of molecular evolution. It is commonly accepted that there is a ‘general molecular slow-down of hominoids’, but interestingly the rates of muscle evolution in the nodes leading and within the hominoid clade are higher than those in the vast majority of other primate clades. The rate of muscle evolution at the node leading to Homo (1.77) is higher than that at the nodes leading to Pan (0.89) and particularly to Gorilla (0.28). Notably, the rates of muscle evolution at the major euarchontan and primate nodes are different, but within each major primate clade (Strepsirrhini, Platyrrhini, Cercopithecidae and Hominoidea) the rates at the various nodes, and particularly at the nodes leading to the higher groups (i.e. including more than one genera), are strikingly similar. We explore the implications of these new data for the tempo and mode of primate and human evolution. PMID:23320764

  7. Phosphoproteomic analysis reveals compensatory effects in the piriform cortex of VX nerve agent exposed rats.

    PubMed

    Nirujogi, Raja Sekhar; Wright, James D; Manda, Srikanth S; Zhong, Jun; Na, Chan Hyun; Meyerhoff, James; Benton, Bernard; Jabbour, Rabih; Willis, Kristen; Kim, Min-Sik; Pandey, Akhilesh; Sekowski, Jennifer W

    2015-01-01

    To gain insights into the toxicity induced by the nerve agent VX, an MS-based phosphoproteomic analysis was carried out on the piriform cortex region of brains from VX-treated rats. Using isobaric tag based TMT labeling followed by titanium dioxide enrichment strategy, we identified 9975 unique phosphosites derived from 3287 phosphoproteins. Temporal changes in the phosphorylation status of peptides were observed over a time period of 24 h in rats exposed to a 1× LD50, intravenous (i.v.) dose with the most notable changes occurring at the 1 h postexposure time point. Five major functional classes of proteins exhibited changes in their phosphorylation status: (i) ion channels/transporters, including ATPases, (ii) kinases/phosphatases, (iii) GTPases, (iv) structural proteins, and (v) transcriptional regulatory proteins. This study is the first quantitative phosphoproteomic analysis of VX toxicity in the brain. Understanding the toxicity and compensatory signaling mechanisms will improve the understanding of the complex toxicity of VX in the brain and aid in the elucidation of novel molecular targets that would be important for development of improved countermeasures. All MS data have been deposited in the ProteomeXchange with identifier PXD001184 (http://proteomecentral.proteomexchange.org/dataset/PXD001184). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Orthostatic intolerance: potential pathophysiology and therapy.

    PubMed

    Lu, Chih-Cherng; Tseng, Ching-Jiunn; Tang, Hung-Shang; Tung, Che-Se

    2004-09-30

    Orthostatic intolerance affects an estimated 1 in 500 persons and causes a wide range of disabilities. After essential hypertension, it is the most frequently encountered dysautonomia, accounting for the majority of patients referred to centers specializing in autonomic disorders. Patients are typically young females with symptoms such as dizziness, visual changes, head and neck discomfort, poor concentration, fatigue, palpitations, tremulousness, anxiety, and, in some cases, syncope. Syncope is the most hazardous symptom of orthostatic intolerance, presumably occurring because of impaired cerebral perfusion and in part to compensatory autonomic mechanisms. The etiology of this syndrome is still unclear but is heterogeneous. Orthostatic intolerance used to be characterized by an overall enhancement of noradrenergic tone at rest in some patients and by a patchy dysautonomia of postganglionic sympathetic fibers with a compensatory cardiac sympathetic activation in others. However, recent advances in molecular genetics are improving our understanding of orthostatic intolerance, such as several genetic diseases (such as Ehler-Danlos syndrome and norepinephrine transporter deficiency) presenting with symptoms typical of orthostatic intolerance. Future work will include investigation of genetic functional mutations underlying interindividual differences in autonomic cardiovascular control, body fluid regulation, and vascular regulation in orthostatic intolerance patients. The goal of this review article is to describe recent advances in understanding the pathophysiological mechanisms of orthostatic intolerance and their clinical significance.

  9. Cascading network failure across the Alzheimer’s disease spectrum

    PubMed Central

    Knopman, David S.; Gunter, Jeffrey L.; Graff-Radford, Jonathan; Vemuri, Prashanthi; Boeve, Bradley F.; Petersen, Ronald C.; Weiner, Michael W.; Jack, Clifford R.

    2016-01-01

    Abstract Complex biological systems are organized across various spatiotemporal scales with particular scientific disciplines dedicated to the study of each scale (e.g. genetics, molecular biology and cognitive neuroscience). When considering disease pathophysiology, one must contemplate the scale at which the disease process is being observed and how these processes impact other levels of organization. Historically Alzheimer’s disease has been viewed as a disease of abnormally aggregated proteins by pathologists and molecular biologists and a disease of clinical symptoms by neurologists and psychologists. Bridging the divide between these scales has been elusive, but the study of brain networks appears to be a pivotal inroad to accomplish this task. In this study, we were guided by an emerging systems-based conceptualization of Alzheimer’s disease and investigated changes in brain networks across the disease spectrum. The default mode network has distinct subsystems with unique functional-anatomic connectivity, cognitive associations, and responses to Alzheimer’s pathophysiology. These distinctions provide a window into the systems-level pathophysiology of Alzheimer’s disease. Using clinical phenotyping, metadata, and multimodal neuroimaging data from the Alzheimer’s Disease Neuroimaging Initiative, we characterized the pattern of default mode network subsystem connectivity changes across the entire disease spectrum (n = 128). The two main findings of this paper are (i) the posterior default mode network fails before measurable amyloid plaques and appears to initiate a connectivity cascade that continues throughout the disease spectrum; and (ii) high connectivity between the posterior default mode network and hubs of high connectivity (many located in the frontal lobe) is associated with amyloid accumulation. These findings support a system model best characterized by a cascading network failure—analogous to cascading failures seen in power grids triggered by local overloads proliferating to downstream nodes eventually leading to widespread power outages, or systems failures. The failure begins in the posterior default mode network, which then shifts processing burden to other systems containing prominent connectivity hubs. This model predicts a connectivity ‘overload’ that precedes structural and functional declines and recasts the interpretation of high connectivity from that of a positive compensatory phenomenon to that of a load-shifting process transiently serving a compensatory role. It is unknown whether this systems-level pathophysiology is the inciting event driving downstream molecular events related to synaptic activity embedded in these systems. Possible interpretations include that the molecular-level events drive the network failure, a pathological interaction between the network-level and the molecular-level, or other upstream factors are driving both. PMID:26586695

  10. Role of self-efficacy and anxiety among pre-clinically disabled older adults when using compensatory strategies to complete daily tasks

    PubMed Central

    Higgins, Torrance J.; Janelle, Christopher M.; Naugle, Kelly M.; Knaggs, Jeffrey; Hoover, Brian M.; Marsiske, Michael; Manini, Todd M.

    2012-01-01

    Classic developmental theory suggests that aging is associated with using compensatory strategies to prolong independence. While compensatory strategies are typically considered positive adaptations, they also signify an early phase in the disablement process — commonly known as pre-clinical disability. To build a better understanding of psychological constructs related to these early signs of disability, we examined the contribution of self-efficacy and state anxiety on using compensatory strategies among pre-clinically disabled older adults. Compensatory strategies were observed during performance of daily activities in 257 pre-clinically disabled older adults (67.6 ± 7.04), and self-efficacy and state anxiety were evaluated prior to performing each task. In univariate models, lower self-efficacy and higher anxiety were associated with more compensation (Spearman correlations: 0.15-0.48, p < 0.05). Multivariate logistic regression indicated that low self-efficacy [Odds Ratio (OR): 1.70; 95% Confidence Interval (CI): 1.40-2.08) and high anxiety (OR: 1.34; 95% CI: 1.10-1.63) were positively associated with using ≥ 6 compensatory strategies – a level signifying substantial compensation. When considered jointly with self-efficacy, the association with anxiety was reversed— higher anxiety demonstrated a lower likelihood of using compensation (OR: 0.70-0.73; 95% CI: 0.50-0.99). The addition of self-efficacy might remove the self-defeating cognitions characterizing anxiety allowing the remaining arousal component to appear beneficial. In conclusion, lower self-efficacy and higher anxiety are associated with using compensation to complete daily tasks among pre-clinically disabled older adults. Such psychological constructs may contribute to the use of compensatory strategies and represent future intervention targets to help reduce early signs of disability. PMID:22770713

  11. Comparative analysis of T2 selective division of rami-communicantes (ramicotomy) with T2 sympathetic clipping in the treatment of craniofacial hyperhidrosis.

    PubMed

    Kim, Do Hyung; Paik, Hyo Chae; Lee, Doo Yun

    2004-08-01

    The main cause of dissatisfaction after sympathetic trunk blocking surgery (T2 sympathectomy, sympathetic clipping) for craniofacial hyperhidrosis is compensatory sweating. Preserving sympathetic trunk may decrease the incidence of compensatory sweating, and we introduce T2 ramicotomy, which may better preserve the sympathetic nerve trunk in order to reduce compensatory sweating. From January 2000 to November 2002, video-assisted thoracoscopic (VAT) T2 sympathetic clipping and VAT ramicotomy were performed in 44 patients suffering from craniofacial hyperhidrosis. Twenty-two patients underwent T2 sympathetic clipping (group 1), and 22 underwent division of T2 rami-communicantes (group 2). We retrospectively analyzed the rate of satisfaction, dryness of face, and grade of compensatory sweating. Both groups were similar with respect to facial dryness (P = 0.099). Group 1: excessive dry 5 patients (22.7%), dry 17 patients (77.3%); group 2: excessive dry 3 patients (13.6%), dry 15 patients (68.1%), and persistent sweating 4 patients (18.3%). The rate of satisfaction was 77.3% in group 1, and 63.6% in group 2 with no significant difference (P > 0.05). The rate of compensatory sweating in group 2 (72.7%) was significantly lower than in group 1 (95.4%) (P < 0.039). The chance of embarrassing and disabling compensatory sweating was lower in group 2 than in group 1; 76.5% (embarrassing in 8 patients, disabling in 9) in group 1, and 36.4% (embarrassing in 7 patients, disabling in 1) in group 2 which was statistically significant (P < 0.006). T2 ramicotomy for craniofacial hyperhidrosis lowers the rate of compensatory sweating and excessive dryness of face compared to T2 clipping.

  12. Acute dietary nitrate supplementation enhances compensatory vasodilation during hypoxic exercise in older adults.

    PubMed

    Casey, Darren P; Treichler, David P; Ganger, Charles T; Schneider, Aaron C; Ueda, Kenichi

    2015-01-15

    We have previously demonstrated that aging reduces the compensatory vasodilator response during hypoxic exercise due to blunted nitric oxide (NO) signaling. Recent evidence suggests that NO bioavailability can be augmented by dietary nitrate through the nitrate-nitrite pathway. Thus we tested the hypothesis that acute dietary nitrate supplementation increases the compensatory vasodilator response to hypoxic exercise, particularly in older adults. Thirteen young (25 ± 1 yr) and 12 older (64 ± 2 yr) adults performed rhythmic forearm exercise at 20% of maximum voluntary contraction during normoxia and hypoxia (∼80% O2 saturation); both before (control) and 3 h after beetroot juice (BR) consumption. Forearm vascular conductance (FVC; ml·min(-1)·100 mmHg(-1)) was calculated from forearm blood flow (ml/min) and blood pressure (mmHg). Compensatory vasodilation was defined as the relative increase in FVC due to hypoxic exercise (i.e., % increase compared with respective normoxic exercise trial). Plasma nitrite was determined from venous blood samples obtained before the control trials and each of the exercise trials (normoxia and hypoxia) after BR. Consumption of BR increased plasma nitrite in both young and older adults (P < 0.001). During the control condition, the compensatory vasodilator response to hypoxic exercise was attenuated in older compared with young adults (3.8 ± 1.7% vs. 14.2 ± 1.2%, P < 0.001). Following BR consumption, compensatory vasodilation did not change in young (13.7 ± 3.3%, P = 0.81) adults but was substantially augmented in older adults (11.4 ± 2.1%, P < 0.01). Our data suggest that acute dietary nitrate supplementation increases the compensatory vasodilator response to hypoxic exercise in older but not young adults. Copyright © 2015 the American Physiological Society.

  13. Driven exercise in the absence of binge eating: Implications for purging disorder.

    PubMed

    Lydecker, Janet A; Shea, Megan; Grilo, Carlos M

    2018-02-01

    Purging disorder (PD) is characterized by recurrent purging without objectively large binge-eating episodes. PD has received relatively little attention, and questions remain about the clinical significance of "purging" by exercise that is driven or compulsive (i.e., as extreme compensatory or weight-control behavior). The little available research suggests that individuals who use exercise as a compensatory behavior might have less eating-disorder psychopathology than those who purge by vomiting or laxatives, but those studies have had smaller sample sizes, defined PD using low-frequency thresholds, and defined exercise without weight-compensatory or driven elements. Participants (N = 2,017) completed a web-based survey with established measures of eating-disorder psychopathology, depression, and physical activity. Participants were categorized (regular compensatory driven exercise, PD-E, n = 297; regular compensatory vomiting/laxatives, PD-VL, n = 59; broadly defined anorexia nervosa, AN, n = 20; and no eating-disordered behaviors, NED, n = 1,658) and compared. PD-E, PD-VL, and AN had higher eating-disorder psychopathology and physical activity than NED but did not significantly differ from each other on most domains. PD-VL and AN had higher depression than PD-E, which was higher than NED. Findings suggest that among participants with regularly compensatory behaviors without binge eating, those who use exercise alone have similar levels of associated eating-disorder psychopathology as those who use vomiting/laxatives, although they have lower depression levels and overall frequency of purging. Findings provide further support for the clinical significance of PD. Clinicians and researchers should recognize the severity of driven exercise as a compensatory behavior, and the need for further epidemiological and treatment research. © 2017 Wiley Periodicals, Inc.

  14. Evolution of complex adaptations in molecular systems

    PubMed Central

    Pál, Csaba; Papp, Balázs

    2017-01-01

    A central challenge in evolutionary biology concerns the mechanisms by which complex adaptations arise. Such adaptations depend on the fixation of multiple, highly specific mutations, where intermediate stages of evolution seemingly provide little or no benefit. It is generally assumed that the establishment of complex adaptations is very slow in nature, as evolution of such traits demands special population genetic or environmental circumstances. However, blueprints of complex adaptations in molecular systems are pervasive, indicating that they can readily evolve. We discuss the prospects and limitations of non-adaptive scenarios, which assume multiple neutral or deleterious steps in the evolution of complex adaptations. Next, we examine how complex adaptations can evolve by natural selection in changing environment. Finally, we argue that molecular ’springboards’, such as phenotypic heterogeneity and promiscuous interactions facilitate this process by providing access to new adaptive paths. PMID:28782044

  15. Resource availability and repeated defoliation mediate compensatory growth in trembling aspen (Populus tremuloides) seedlings

    PubMed Central

    Galvez, David A.; Zhang, Bin; Najar, Ahmed

    2014-01-01

    Plant ecologists have debated the mechanisms used by plants to cope with the impact of herbivore damage. While plant resistance mechanisms have received much attention, plant compensatory growth as a type of plant tolerance mechanisms has been less studied. We conducted a greenhouse experiment to evaluate compensatory growth for trembling aspen (Populus tremuloides) seedlings under varying intensities and frequencies of simulated defoliation, with or without nutrient enriched media. For the purpose of this study, changes in biomass production and non-structural carbohydrate concentrations (NSC) of roots and leaves were considered compensatory responses. All defoliated seedlings showed biomass accumulation under low defoliation intensity and frequency, regardless of resource availability; however, as defoliation intensity and frequency increased, compensatory growth of seedlings was altered depending on resource availability. Seedlings in a resource-rich environment showed complete compensation, in contrast responses ranged from undercompensation to complete compensation in a resource-limited environment. Furthermore, at the highest defoliation intensity and frequency, NSC concentrations in leaves and roots were similar between defoliated and non-defoliated seedlings in a resource-rich environment; in contrast, defoliated seedlings with limited resources sustained the most biomass loss, had lower amounts of stored NSC. Using these results, we developed a new predictive framework incorporating the interactions between frequency and intensity of defoliation and resource availability as modulators of plant compensatory responses. PMID:25083352

  16. Expanded level of sympathetic chain removal does not increase the incidence or severity of compensatory hyperhidrosis after endoscopic thoracic sympathectomy.

    PubMed

    Gunn, Tyler M; Davis, Diane M; Speicher, James E; Rossi, Nicholas P; Parekh, Kalpaj R; Lynch, William R; Iannettoni, Mark D

    2014-12-01

    Compensatory hyperhidrosis is a common devastating adverse effect after endoscopic thoracic sympathectomy for patients undergoing surgical treatment of primary hyperhidrosis. We sought to determine whether a correlation existed in our patient population between the level and extent of sympathetic chain resection and the subsequent development of compensatory hyperhidrosis. All patients undergoing endoscopic thoracic sympathectomy in the T2-T3, T2-T4, T2-T5, or T2-T6 levels for palmar or axillary hyperhidrosis at the University of Iowa Hospital and Clinics (n = 97) from January 2004 to January 2013 were retrospectively reviewed. Differences in the preoperative patient characteristics were not statistically significant among the patients receiving T2-T3, T2-T4, T2-T5, or T2-T6 level resections. Of the 97 included patients, 28 (29%) experienced transient compensatory hyperhidrosis and 4 (4%) complained of severe compensatory hyperhidrosis and required additional treatment. No operative mortalities occurred, and the morbidity was similar among the groups. Most patients had successful outcomes after undergoing extensive resection without changes in the incidence of compensatory hyperhidrosis. Therefore, we recommend performing complete and adequate resection for relief of symptoms in patients with primary hyperhidrosis. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  17. Categorization of compensatory motions in transradial myoelectric prosthesis users.

    PubMed

    Hussaini, Ali; Zinck, Arthur; Kyberd, Peter

    2017-06-01

    Prosthesis users perform various compensatory motions to accommodate for the loss of the hand and wrist as well as the reduced functionality of a prosthetic hand. Investigate different compensation strategies that are performed by prosthesis users. Comparative analysis. A total of 20 able-bodied subjects and 4 prosthesis users performed a set of bimanual activities. Movements of the trunk and head were recorded using a motion capture system and a digital video recorder. Clinical motion angles were calculated to assess the compensatory motions made by the prosthesis users. The video recording also assisted in visually identifying the compensations. Compensatory motions by the prosthesis users were evident in the tasks performed (slicing and stirring activities) as compared to the benchmark of able-bodied subjects. Compensations took the form of a measured increase in range of motion, an observed adoption of a new posture during task execution, and prepositioning of items in the workspace prior to initiating a given task. Compensatory motions were performed by prosthesis users during the selected tasks. These can be categorized into three different types of compensations. Clinical relevance Proper identification and classification of compensatory motions performed by prosthesis users into three distinct forms allows clinicians and researchers to accurately identify and quantify movement. It will assist in evaluating new prosthetic interventions by providing distinct terminology that is easily understood and can be shared between research institutions.

  18. Compensatory Saccades Are Associated With Physical Performance in Older Adults: Data From the Baltimore Longitudinal Study of Aging.

    PubMed

    Xie, Yanjun; Anson, Eric R; Simonsick, Eleanor M; Studenski, Stephanie A; Agrawal, Yuri

    2017-03-01

    To determine whether compensatory saccade metrics observed in the video head impulse test, specifically saccade amplitude and latency, predict physical performance. Cross-sectional analysis of the Baltimore Longitudinal Study of Aging, a prospective cohort study. National Institute on Aging Intramural Research Program Clinical Research Unit in Baltimore, Maryland. Community-dwelling older adults. Video head impulse testing was performed, and compensatory saccades and horizontal vestibulo-ocular reflex (VOR) gain were measured. Physical performance was assessed using the Short Physical Performance Battery (SPPB), which included the feet side-by-side, semitandem, tandem, and single-leg stance; repeated chair stands; and usual gait speed measurements. Compensatory saccade amplitude and latency, VOR gain, and SPPB performance. In 183 participants who underwent vestibular and SPPB testing (mean age 71.8 yr; 53% females), both higher mean saccade amplitude (odds ratio [OR] =1.62, p = 0.010) and shorter mean saccade latency (OR = 0.88, p = 0.004) were associated with a higher odds of failing the tandem stand task. In contrast, VOR gain was not associated with any physical performance measure. We observed in a cohort of healthy older adults that compensatory saccade amplitude and latency were associated with tandem stance performance. Compensatory saccade metrics may provide insights into capturing the impact of vestibular loss on physical function in older adults.

  19. The Jukes-Cantor Model of Molecular Evolution

    ERIC Educational Resources Information Center

    Erickson, Keith

    2010-01-01

    The material in this module introduces students to some of the mathematical tools used to examine molecular evolution. This topic is standard fare in many mathematical biology or bioinformatics classes, but could also be suitable for classes in linear algebra or probability. While coursework in matrix algebra, Markov processes, Monte Carlo…

  20. Time Evolution of the Giant Molecular Cloud Mass Functions across Galactic Disks

    NASA Astrophysics Data System (ADS)

    Kobayashi, Masato I. N.; Inutsuka, Shu-Ichiro; Kobayashi, Hiroshi; Hasegawa, Kenji

    2017-01-01

    We formulate and conduct the time-integration of time evolution equation for the giant molecular cloud mass function (GMCMF) including the cloud-cloud collision (CCC) effect. Our results show that the CCC effect is only limited in the massive-end of the GMCMF and indicate that future high resolution and sensitivity radio observations may constrain giant molecular cloud (GMC) timescales by observing the GMCMF slope in the lower mass regime.

  1. Evolutionary responses to climate change in parasitic systems.

    PubMed

    Chaianunporn, Thotsapol; Hovestadt, Thomas

    2015-08-01

    Species may respond to climate change in many ecological and evolutionary ways. In this simulation study, we focus on the concurrent evolution of three traits in response to climate change, namely dispersal probability, temperature tolerance (or niche width), and temperature preference (optimal habitat). More specifically, we consider evolutionary responses in host species involved in different types of interaction, that is parasitism or commensalism, and for low or high costs of a temperature tolerance-fertility trade-off (cost of generalization). We find that host species potentially evolve all three traits simultaneously in response to increasing temperature but that the evolutionary response interacts and may be compensatory depending on the conditions. The evolutionary adjustment of temperature preference is slower in the parasitism than in commensalism scenario. Parasitism, in turn, selects for higher temperature tolerance and increased dispersal. High costs for temperature tolerance (i.e. generalization) restrict evolution of tolerance and thus lead to a faster response in temperature preference than that observed under low costs. These results emphasize the possible role of biotic interactions and the importance of 'multidimensional' evolutionary responses to climate change. © 2015 John Wiley & Sons Ltd.

  2. Second Symposium on Chemical Evolution and the Origin of Life

    NASA Technical Reports Server (NTRS)

    Devincenzi, D. L. (Editor); model. (Editor)

    1986-01-01

    Recent findings by NASA Exobiology investigators are reported. Scientific papers are presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI).

  3. Second Symposium on Chemical Evolution and the Origin of Life

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Devincenzi, D.L.; Dufour, P.A.

    1986-05-01

    Recent findings by NASA Exobiology investigators are reported. Scientific papers are presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI).

  4. Compensatory Education? No!

    ERIC Educational Resources Information Center

    Maxwell, B. L.

    1972-01-01

    Compensatory Education at its best is merely iodine being used to cure cancer. The problems of America's social, political, and educational systems are far too mammoth to be placated by this feeble effort. (Author)

  5. Compensatory Plasticity in the Deaf Brain: Effects on Perception of Music

    PubMed Central

    Good, Arla; Reed, Maureen J.; Russo, Frank A.

    2014-01-01

    When one sense is unavailable, sensory responsibilities shift and processing of the remaining modalities becomes enhanced to compensate for missing information. This shift, referred to as compensatory plasticity, results in a unique sensory experience for individuals who are deaf, including the manner in which music is perceived. This paper evaluates the neural, behavioural and cognitive evidence for compensatory plasticity following auditory deprivation and considers how this manifests in a unique experience of music that emphasizes visual and vibrotactile modalities. PMID:25354235

  6. Compensatory Mitigation Factsheet

    EPA Pesticide Factsheets

    For unavoidable impacts to wetlands, streams and other aquatic resources from authorized discharges of dredged or fill material, compensatory mitigation is required to replace the loss of wetland and aquatic resource functions in the watershed.

  7. Compensatory Mitigation Rule Factsheet

    EPA Pesticide Factsheets

    A two page fact sheet developed by EPA for the public to reinforce the requirements under the 2008 Compensatory Mitigation Rule to adhere to the “mitigation sequence” of “avoid, minimize and compensate”.

  8. Effects of hypothermically reduced plantar skin inputs on anticipatory and compensatory balance responses.

    PubMed

    Germano, Andresa M C; Schmidt, Daniel; Milani, Thomas L

    2016-06-29

    Anticipatory and compensatory balance responses are used by the central nervous system (CNS) to preserve balance, hence they significantly contribute to the understanding of physiological mechanisms of postural control. It is well established that various sensory systems contribute to the regulation of balance. However, it is still unclear which role each individual sensory system (e.g. plantar mechanoreceptors) plays in balance regulation. This becomes also evident in various patient populations, for instance in diabetics with reduced plantar sensitivity. To investigate these sensory mechanisms, approaches like hypothermia to deliberately reduce plantar afferent input have been applied. But there are some limitations regarding hypothermic procedures in previous studies: Not only plantar aspects of the feet might be affected and maintaining the hypothermic effect during data collection. Therefore, the aim of the present study was to induce a permanent and controlled plantar hypothermia and to examine its effects on anticipatory and compensatory balance responses. We hypothesized deteriorations in anticipatory and compensatory balance responses as increased center of pressure excursions (COP) and electromyographic activity (EMG) in response to the hypothermic plantar procedure. 52 healthy and young subjects (23.6 ± 3.0 years) performed balance tests (unexpected perturbations). Subjects' foot soles were exposed to three temperatures while standing upright: 25, 12 and 0 °C. COP and EMG were analyzed during two intervals of anticipatory and one interval of compensatory balance responses (intervals 0, 1 and 2, respectively). Similar plantar temperatures confirmed the successful implementation of the thermal platform. No significant COP and EMG differences were found for the anticipatory responses (intervals 0 and 1) under the hyperthermia procedure. Parameters in interval 2 showed generally decreased values in response to cooling. No changes in anticipatory responses were found possibly due to sensory compensation processes of other intact afferents. Decreased compensatory responses may be interpreted as the additional balance threat, creating a more cautious behavior causing the CNS to generate a kind of over-compensatory behavior. Contrary to the expectations, there were different anticipatory and compensatory responses after reduced plantar inputs, thereby, revealing alterations in the organization of CNS inputs and outputs according to different task difficulties.

  9. Evolution of egg coats: linking molecular biology and ecology.

    PubMed

    Shu, Longfei; Suter, Marc J-F; Räsänen, Katja

    2015-08-01

    One central goal of evolutionary biology is to explain how biological diversity emerges and is maintained in nature. Given the complexity of the phenotype and the multifaceted nature of inheritance, modern evolutionary ecological studies rely heavily on the use of molecular tools. Here, we show how molecular tools help to gain insight into the role of egg coats (i.e. the extracellular structures surrounding eggs and embryos) in evolutionary diversification. Egg coats are maternally derived structures that have many biological functions from mediating fertilization to protecting the embryo from environmental hazards. They show great molecular, structural and functional diversity across species, but intraspecific variability and the role of ecology in egg coat evolution have largely been overlooked. Given that much of the variation that influences egg coat function is ultimately determined by their molecular phenotype, cutting-edge molecular tools (e.g. proteomics, glycomics and transcriptomics), combined with functional assays, are needed for rigorous inferences on their evolutionary ecology. Here, we identify key research areas and highlight emerging molecular techniques that can increase our understanding of the role of egg coats in the evolution of biological diversity, from adaptation to speciation. © 2015 John Wiley & Sons Ltd.

  10. Bacterial flagella and Type III secretion: case studies in the evolution of complexity.

    PubMed

    Pallen, M J; Gophna, U

    2007-01-01

    Bacterial flagella at first sight appear uniquely sophisticated in structure, so much so that they have even been considered 'irreducibly complex' by the intelligent design movement. However, a more detailed analysis reveals that these remarkable pieces of molecular machinery are the product of processes that are fully compatible with Darwinian evolution. In this chapter we present evidence for such processes, based on a review of experimental studies, molecular phylogeny and microbial genomics. Several processes have played important roles in flagellar evolution: self-assembly of simple repeating subunits, gene duplication with subsequent divergence, recruitment of elements from other systems ('molecular bricolage'), and recombination. We also discuss additional tentative new assignments of homology (FliG with MgtE, FliO with YscJ). In conclusion, rather than providing evidence of intelligent design, flagellar and non-flagellar Type III secretion systems instead provide excellent case studies in the evolution of complex systems from simpler components.

  11. Background on 2008 Compensatory Mitigation Rulemaking

    EPA Pesticide Factsheets

    In 2008 EPA and the Corps issued revised regulations governing compensatory mitigation for authorized impacts to wetlands, streams, and other waters of the U.S. under Section 404 of the Clean Water Act.

  12. 2008 Compensatory Mitigation Rule: General Requirements

    EPA Pesticide Factsheets

    Compensatory mitigation involves actions taken to offset unavoidable adverse impacts to wetlands, streams and other aquatic resources authorized by Clean Water Act section 404 permits and other Department of the Army (DA) permits

  13. DNA Re-EvolutioN: a game for learning molecular genetics and evolution.

    PubMed

    Miralles, Laura; Moran, Paloma; Dopico, Eduardo; Garcia-Vazquez, Eva

    2013-01-01

    Evolution is a main concept in biology, but not many students understand how it works. In this article we introduce the game DNA Re-EvolutioN as an active learning tool that uses genetic concepts (DNA structure, transcription and translation, mutations, natural selection, etc.) as playing rules. Students will learn about molecular evolution while playing a game that mixes up theory and entertainment. The game can be easily adapted to different educational levels. The main goal of this play is to arrive at the end of the game with the longest protein. Students play with pawns and dices, a board containing hypothetical events (mutations, selection) that happen to molecules, "Evolution cards" with indications for DNA mutations, prototypes of a DNA and a mRNA chain with colored "nucleotides" (plasticine balls), and small pieces simulating t-RNA with aminoacids that will serve to construct a "protein" based on the DNA chain. Students will understand how changes in DNA affect the final protein product and may be subjected to positive or negative selection, using a didactic tool funnier than classical theory lectures and easier than molecular laboratory experiments: a flexible and feasible game to learn and enjoy molecular evolution at no-cost. The game was tested by majors and non-majors in genetics from 13 different countries and evaluated with pre- and post-tests obtaining very positive results. © 2013 by The International Union of Biochemistry and Molecular Biology.

  14. Genes involved in convergent evolution of eusociality in bees

    PubMed Central

    Woodard, S. Hollis; Fischman, Brielle J.; Venkat, Aarti; Hudson, Matt E.; Varala, Kranthi; Cameron, Sydney A.; Clark, Andrew G.; Robinson, Gene E.

    2011-01-01

    Eusociality has arisen independently at least 11 times in insects. Despite this convergence, there are striking differences among eusocial lifestyles, ranging from species living in small colonies with overt conflict over reproduction to species in which colonies contain hundreds of thousands of highly specialized sterile workers produced by one or a few queens. Although the evolution of eusociality has been intensively studied, the genetic changes involved in the evolution of eusociality are relatively unknown. We examined patterns of molecular evolution across three independent origins of eusociality by sequencing transcriptomes of nine socially diverse bee species and combining these data with genome sequence from the honey bee Apis mellifera to generate orthologous sequence alignments for 3,647 genes. We found a shared set of 212 genes with a molecular signature of accelerated evolution across all eusocial lineages studied, as well as unique sets of 173 and 218 genes with a signature of accelerated evolution specific to either highly or primitively eusocial lineages, respectively. These results demonstrate that convergent evolution can involve a mosaic pattern of molecular changes in both shared and lineage-specific sets of genes. Genes involved in signal transduction, gland development, and carbohydrate metabolism are among the most prominent rapidly evolving genes in eusocial lineages. These findings provide a starting point for linking specific genetic changes to the evolution of eusociality. PMID:21482769

  15. 29 CFR 553.12 - Exclusion for employees of legislative branches.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) Employees of State or local legislative libraries do not come within this statutory exclusion. Also... not come within this exclusion. Section 7(o)—Compensatory Time and Compensatory Time Off ...

  16. 29 CFR 553.12 - Exclusion for employees of legislative branches.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Employees of State or local legislative libraries do not come within this statutory exclusion. Also... not come within this exclusion. Section 7(o)—Compensatory Time and Compensatory Time Off ...

  17. 29 CFR 553.12 - Exclusion for employees of legislative branches.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) Employees of State or local legislative libraries do not come within this statutory exclusion. Also... not come within this exclusion. Section 7(o)—Compensatory Time and Compensatory Time Off ...

  18. 29 CFR 553.12 - Exclusion for employees of legislative branches.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) Employees of State or local legislative libraries do not come within this statutory exclusion. Also... not come within this exclusion. Section 7(o)—Compensatory Time and Compensatory Time Off ...

  19. Handbook on Coral Reef Impacts: Avoidance, Minimization, Compensatory Mitigation, and Restoration

    EPA Pesticide Factsheets

    This Handbook provides a general summary of current avoidance, minimization, compensatory mitigation, and restoration strategies that may help address physical damage resulting from direct adverse impacts to coral reefs.

  20. Compensatory Mitigation Rule Final Environmental Assessment

    EPA Pesticide Factsheets

    EA performed to determine the costs resulting from implementation of the Compensatory Mitigation Rule and the extent to which the rule changes aggregate mitigation costs borne by permittees and Corps administrative burdens and associated costs.

  1. Compensatory Mitigation for Losses of Aquatic Resources; Final Rule

    EPA Pesticide Factsheets

    These regulations are designed to improve the effectiveness of compensatory mitigation to replace lost aquatic resource functions and area, and increase the efficiency and predictability of the mitigation project review process.

  2. Audiovisual materials are effective for enhancing the correction of articulation disorders in children with cleft palate.

    PubMed

    Pamplona, María Del Carmen; Ysunza, Pablo Antonio; Morales, Santiago

    2017-02-01

    Children with cleft palate frequently show speech disorders known as compensatory articulation. Compensatory articulation requires a prolonged period of speech intervention that should include reinforcement at home. However, frequently relatives do not know how to work with their children at home. To study whether the use of audiovisual materials especially designed for complementing speech pathology treatment in children with compensatory articulation can be effective for stimulating articulation practice at home and consequently enhancing speech normalization in children with cleft palate. Eighty-two patients with compensatory articulation were studied. Patients were randomly divided into two groups. Both groups received speech pathology treatment aimed to correct articulation placement. In addition, patients from the active group received a set of audiovisual materials to be used at home. Parents were instructed about strategies and ideas about how to use the materials with their children. Severity of compensatory articulation was compared at the onset and at the end of the speech intervention. After the speech therapy period, the group of patients using audiovisual materials at home demonstrated significantly greater improvement in articulation, as compared with the patients receiving speech pathology treatment on - site without audiovisual supporting materials. The results of this study suggest that audiovisual materials especially designed for practicing adequate articulation placement at home can be effective for reinforcing and enhancing speech pathology treatment of patients with cleft palate and compensatory articulation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Rehabilitation or compensation: time for a fresh perspective on speech and language therapy for dysphagia and Parkinson's disease?

    PubMed

    Smith, Sarah K; Roddam, Hazel; Sheldrick, Heulwen

    2012-01-01

    Dysphagia is a common symptom of Parkinson's disease and can have negative consequences for physical health and quality of life. A variety of treatment options are available to clinicians working with people who have dysphagia and Parkinson's disease. These options can be broadly categorized as being compensatory or rehabilitative in nature. To explore the evidence behind treatment options available to clinicians working with dysphagia and Parkinson's disease and to draw conclusions about whether compensatory or rehabilitative approaches are likely to provide the best outcomes for our patients. A critical literature review of compensatory and rehabilitative interventions for dysphagia in Parkinson's disease was undertaken. Relevant studies were analysed for their robustness and potential clinical applications. General conclusions were drawn based on the evidence base identified in this review. This review outlines the lack of evidence supporting both compensatory and rehabilitative methods of treating dysphagia in Parkinson's disease. It directs clinicians and researchers towards areas that require further investigation. To date, compensatory methods of treating dysphagia in Parkinson's disease have received more research attention than rehabilitative methods and yet neither approach has a strong evidence base. This review argues that rehabilitative methods could possibly have greater potential to increase swallowing safety and improve quality of life in the long-term than compensatory methods alone. However, at present there is a lack of research in this area. © 2012 Royal College of Speech and Language Therapists.

  4. Awareness tool for safe and responsible driving (OSCAR): a potential educational intervention for increasing interest, openness and knowledge about the abilities required and compensatory strategies among older drivers.

    PubMed

    Levasseur, Mélanie; Audet, Thérèse; Gélinas, Isabelle; Bédard, Michel; Langlais, Marie-Ève; Therrien, France-Hélène; Renaud, Judith; Coallier, Jean-Claude; D'Amours, Monia

    2015-01-01

    This pilot study aimed to verify the impact of the awareness tool for safe and responsible driving (OSCAR) on older adults' (1) interest, openness, and knowledge about the abilities and compensatory strategies required for safe driving; (2) awareness of changes that have occurred in their own driving abilities; and (3) actual utilization of compensatory strategies. A preexperimental design, including a pretest (T0) and posttest (T1) 8 to 10 weeks after exposure to the intervention, was used with 48 drivers aged between 67 and 84. The participants had a valid driving license and drove at least once a week. Overall, the results demonstrate that OSCAR increased interest, openness, and knowledge about the abilities and compensatory strategies of older drivers (P <.01). After exposure to OSCAR, the majority of the participants confirmed that changes had occurred in at least one of their abilities. Moreover, half of the older drivers reported having started using 6 or more compensatory strategies. In summary, in addition to increasing older adults' interest, openness, and knowledge to discussion about driving, OSCAR also improved awareness of the changes that could negatively impact safe driving and enhanced utilization of compensatory strategies. While promoting safe driving and the prevention of crashes and injuries, this intervention could ultimately help older adults maintain or increase their transportation mobility. More studies are needed to further evaluate OSCAR and identify ways to improve its effectiveness.

  5. Dietary nitrate restores compensatory vasodilation and exercise capacity in response to a compromise in oxygen delivery in the noncompensator phenotype.

    PubMed

    Bentley, Robert F; Walsh, Jeremy J; Drouin, Patrick J; Velickovic, Aleksandra; Kitner, Sarah J; Fenuta, Alyssa M; Tschakovsky, Michael E

    2017-09-01

    Recently, dietary nitrate supplementation has been shown to improve exercise capacity in healthy individuals through a potential nitrate-nitrite-nitric oxide pathway. Nitric oxide has been shown to play an important role in compensatory vasodilation during exercise under hypoperfusion. Previously, we established that certain individuals lack a vasodilation response when perfusion pressure reductions compromise exercising muscle blood flow. Whether this lack of compensatory vasodilation in healthy, young individuals can be restored with dietary nitrate supplementation is unknown. Six healthy (21 ± 2 yr), recreationally active men completed a rhythmic forearm exercise. During steady-state exercise, the exercising arm was rapidly transitioned from an uncompromised (below heart) to a compromised (above heart) position, resulting in a reduction in local pressure of -31 ± 1 mmHg. Exercise was completed following 5 days of nitrate-rich (70 ml, 0.4 g nitrate) and nitrate-depleted (70 ml, ~0 g nitrate) beetroot juice consumption. Forearm blood flow (in milliliters per minute; brachial artery Doppler and echo ultrasound), mean arterial blood pressure (in millimeters of mercury; finger photoplethysmography), exercising forearm venous effluent (ante-cubital vein catheter), and plasma nitrite concentrations (chemiluminescence) revealed two distinct vasodilatory responses: nitrate supplementation increased (plasma nitrite) compared with placebo (245 ± 60 vs. 39 ± 9 nmol/l; P < 0.001), and compensatory vasodilation was present following nitrate supplementation (568 ± 117 vs. 714 ± 139 ml ⋅ min -1 ⋅ 100 mmHg -1 ; P = 0.005) but not in placebo (687 ± 166 vs. 697 ± 171 min -1 ⋅ 100 mmHg -1 ; P = 0.42). As such, peak exercise capacity was reduced to a lesser degree (-4 ± 39 vs. -39 ± 27 N; P = 0.01). In conclusion, dietary nitrate supplementation during a perfusion pressure challenge is an effective means of restoring exercise capacity and enabling compensatory vasodilation. NEW & NOTEWORTHY Previously, we identified young, healthy persons who suffer compromised exercise tolerance when exercising muscle perfusion pressure is reduced as a result of a lack of compensatory vasodilation. The ability of nitrate supplementation to restore compensatory vasodilation in such noncompensators is unknown. We demonstrated that beetroot juice supplementation led to compensatory vasodilation and restored perfusion and exercise capacity. Elevated plasma nitrite is an effective intervention for correcting the absence of compensatory vasodilation in the noncompensator phenotype. Copyright © 2017 the American Physiological Society.

  6. Can clues from evolution unlock the molecular development of the cerebellum?

    PubMed

    Butts, Thomas; Chaplin, Natalie; Wingate, Richard J T

    2011-02-01

    The cerebellum sits at the rostral end of the vertebrate hindbrain and is responsible for sensory and motor integration. Owing to its relatively simple architecture, it is one of the most powerful model systems for studying brain evolution and development. Over the last decade, the combination of molecular fate mapping techniques in the mouse and experimental studies, both in vitro and in vivo, in mouse and chick have significantly advanced our understanding of cerebellar neurogenesis in space and time. In amniotes, the most numerous cell type in the cerebellum, and indeed the brain, is the cerebellar granule neurons, and these are born from a transient secondary proliferative zone, the external granule layer (EGL), where proliferation is driven by sonic hedgehog signalling and causes cerebellar foliation. Recent studies in zebrafish and sharks have shown that while the molecular mechanisms of neurogenesis appear conserved across vertebrates, the EGL as a site of shh-driven transit amplification is not, and is therefore implicated as a key amniote innovation that facilitated the evolution of the elaborate foliated cerebella found in birds and mammals. Ellucidating the molecular mechanisms underlying the origin of the EGL in evolution could have significant impacts on our understanding of the molecular details of cerebellar development.

  7. Generation of Synthetic Copolymer Libraries by Combinatorial Assembly on Nucleic Acid Templates.

    PubMed

    Kong, Dehui; Yeung, Wayland; Hili, Ryan

    2016-07-11

    Recent advances in nucleic acid-templated copolymerization have expanded the scope of sequence-controlled synthetic copolymers beyond the molecular architectures witnessed in nature. This has enabled the power of molecular evolution to be applied to synthetic copolymer libraries to evolve molecular function ranging from molecular recognition to catalysis. This Review seeks to summarize different approaches available to generate sequence-defined monodispersed synthetic copolymer libraries using nucleic acid-templated polymerization. Key concepts and principles governing nucleic acid-templated polymerization, as well as the fidelity of various copolymerization technologies, will be described. The Review will focus on methods that enable the combinatorial generation of copolymer libraries and their molecular evolution for desired function.

  8. Compensatory-step training of healthy, mobile people with unilateral, transfemoral or knee disarticulation amputations: A potential intervention for trip-related falls.

    PubMed

    Crenshaw, Jeremy R; Kaufman, Kenton R; Grabiner, Mark D

    2013-07-01

    The purpose of this study was to evaluate the effects of compensatory-step training of healthy, mobile, young-to-middle aged people with unilateral, transfemoral or knee disarticulation amputations. Outcomes of interest included recovery success, reliance on the prosthesis, and the kinematic variables relevant to trip recovery. Over the course of six training sessions, five subjects responded to postural disturbances that necessitated forward compensatory steps to avoid falling. Subjects improved their ability to recover from these postural disturbances without falling or hopping on the non-prosthetic limb. Subjects improved their compensatory stepping response by decreasing trunk flexion and increasing the sagittal plane distance between the body center of mass and the stepping foot. In response to more challenging disturbances, these training-related improvements were not observed for the initial step with the non-prosthetic limb. Regardless of the stepping limb, step length and the change in pelvic height were not responsive to training. This study exhibits the potential benefits of a compensatory-step training program for amputees and informs future improvements to the protocol. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Flexible compensation of uniparental care: female poison frogs take over when males disappear.

    PubMed

    Ringler, Eva; Pašukonis, Andrius; Fitch, W Tecumseh; Huber, Ludwig; Hödl, Walter; Ringler, Max

    2015-01-01

    Parental care systems are shaped by costs and benefits to each sex of investing into current versus future progeny. Flexible compensatory parental care is mainly known in biparental species, particularly where parental desertion or reduction of care by 1 parent is common. The other parent can then compensate this loss by either switching parental roles and/or by increasing its own parental effort. In uniparental species, desertion of the caregiver usually leads to total brood loss. In the poison frog, Allobates femoralis , obligatory tadpole transport (TT) is generally performed by males, whereas females abandon their clutches after oviposition. Nevertheless, in a natural population we previously observed 7.8% of TT performed by females, which we could link to the absence of the respective fathers. In the following experiment, under laboratory conditions, all tested A. femoralis females flexibly took over parental duties, but only when their mates were removed. Our findings provide clear evidence for compensatory flexibility in a species with unisexual parental care. Contrary to the view of amphibian parental care as being stereotypical and fixed, these results demonstrate behavioral flexibility as an adaptive response to environmental and social uncertainty. Behavioral flexibility might actually represent a crucial step in the evolutionary transition from uniparental to biparental care in poison frogs. We suspect that across animal species flexible parental roles are much more common than previously thought and suggest the idea of a 3-dimensional continuum regarding flexibility, parental involvement, and timing, when thinking about the evolution of parental care.

  10. 5 CFR 550.1409 - Inapplicability of premium pay and aggregate pay caps.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1409 Inapplicability of premium pay and aggregate pay caps. Accrued compensatory time off under this subpart is not...

  11. 5 CFR 550.1409 - Inapplicability of premium pay and aggregate pay caps.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1409 Inapplicability of premium pay and aggregate pay caps. Accrued compensatory time off under this subpart is not...

  12. 5 CFR 550.1409 - Inapplicability of premium pay and aggregate pay caps.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1409 Inapplicability of premium pay and aggregate pay caps. Accrued compensatory time off under this subpart is not...

  13. 5 CFR 550.1409 - Inapplicability of premium pay and aggregate pay caps.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1409 Inapplicability of premium pay and aggregate pay caps. Accrued compensatory time off under this subpart is not...

  14. 5 CFR 550.1409 - Inapplicability of premium pay and aggregate pay caps.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1409 Inapplicability of premium pay and aggregate pay caps. Accrued compensatory time off under this subpart is not...

  15. Biological intuition in alignment-free methods: response to Posada.

    PubMed

    Ragan, Mark A; Chan, Cheong Xin

    2013-08-01

    A recent editorial in Journal of Molecular Evolution highlights opportunities and challenges facing molecular evolution in the era of next-generation sequencing. Abundant sequence data should allow more-complex models to be fit at higher confidence, making phylogenetic inference more reliable and improving our understanding of evolution at the molecular level. However, concern that approaches based on multiple sequence alignment may be computationally infeasible for large datasets is driving the development of so-called alignment-free methods for sequence comparison and phylogenetic inference. The recent editorial characterized these approaches as model-free, not based on the concept of homology, and lacking in biological intuition. We argue here that alignment-free methods have not abandoned models or homology, and can be biologically intuitive.

  16. Social parasitism and the molecular basis of phenotypic evolution.

    PubMed

    Cini, Alessandro; Patalano, Solenn; Segonds-Pichon, Anne; Busby, George B J; Cervo, Rita; Sumner, Seirian

    2015-01-01

    Contrasting phenotypes arise from similar genomes through a combination of losses, gains, co-option and modifications of inherited genomic material. Understanding the molecular basis of this phenotypic diversity is a fundamental challenge in modern evolutionary biology. Comparisons of the genes and their expression patterns underlying traits in closely related species offer an unrivaled opportunity to evaluate the extent to which genomic material is reorganized to produce novel traits. Advances in molecular methods now allow us to dissect the molecular machinery underlying phenotypic diversity in almost any organism, from single-celled entities to the most complex vertebrates. Here we discuss how comparisons of social parasites and their free-living hosts may provide unique insights into the molecular basis of phenotypic evolution. Social parasites evolve from a eusocial ancestor and are specialized to exploit the socially acquired resources of their closely-related eusocial host. Molecular comparisons of such species pairs can reveal how genomic material is re-organized in the loss of ancestral traits (i.e., of free-living traits in the parasites) and the gain of new ones (i.e., specialist traits required for a parasitic lifestyle). We define hypotheses on the molecular basis of phenotypes in the evolution of social parasitism and discuss their wider application in our understanding of the molecular basis of phenotypic diversity within the theoretical framework of phenotypic plasticity and shifting reaction norms. Currently there are no data available to test these hypotheses, and so we also provide some proof of concept data using the paper wasp social parasite/host system (Polistes sulcifer-Polistes dominula). This conceptual framework and first empirical data provide a spring-board for directing future genomic analyses on exploiting social parasites as a route to understanding the evolution of phenotypic specialization.

  17. Social parasitism and the molecular basis of phenotypic evolution

    PubMed Central

    Cini, Alessandro; Patalano, Solenn; Segonds-Pichon, Anne; Busby, George B. J.; Cervo, Rita; Sumner, Seirian

    2015-01-01

    Contrasting phenotypes arise from similar genomes through a combination of losses, gains, co-option and modifications of inherited genomic material. Understanding the molecular basis of this phenotypic diversity is a fundamental challenge in modern evolutionary biology. Comparisons of the genes and their expression patterns underlying traits in closely related species offer an unrivaled opportunity to evaluate the extent to which genomic material is reorganized to produce novel traits. Advances in molecular methods now allow us to dissect the molecular machinery underlying phenotypic diversity in almost any organism, from single-celled entities to the most complex vertebrates. Here we discuss how comparisons of social parasites and their free-living hosts may provide unique insights into the molecular basis of phenotypic evolution. Social parasites evolve from a eusocial ancestor and are specialized to exploit the socially acquired resources of their closely-related eusocial host. Molecular comparisons of such species pairs can reveal how genomic material is re-organized in the loss of ancestral traits (i.e., of free-living traits in the parasites) and the gain of new ones (i.e., specialist traits required for a parasitic lifestyle). We define hypotheses on the molecular basis of phenotypes in the evolution of social parasitism and discuss their wider application in our understanding of the molecular basis of phenotypic diversity within the theoretical framework of phenotypic plasticity and shifting reaction norms. Currently there are no data available to test these hypotheses, and so we also provide some proof of concept data using the paper wasp social parasite/host system (Polistes sulcifer—Polistes dominula). This conceptual framework and first empirical data provide a spring-board for directing future genomic analyses on exploiting social parasites as a route to understanding the evolution of phenotypic specialization. PMID:25741361

  18. Curve Modulation and Apex Migration Using Shilla Growth Guidance Rods for Early-onset Scoliosis at 5-Year Follow-up.

    PubMed

    Wilkinson, John T; Songy, Chad E; Bumpass, David B; McCullough, Francis L; McCarthy, Richard E

    2017-04-03

    The Shilla procedure was designed to correct and control early-onset spinal deformity while harnessing a child's remaining spinal growth. It allows for controlled axial skeletal growth within the construct, avoiding the need for frequent surgeries to lengthen implants. We hypothesized that curve characteristics evolve over time after initial apex fusion and placement of the Shilla implants. The purpose of this study was to identify trends in curve evolution after Shilla implantation and understand how these changes influence ultimate outcome. A single-center, retrospective review of all patients with Shilla implants in place for ≥5 years yielded 21 patients. Charts and radiographs were reviewed to compare coronal curve characteristics preoperatively, postoperatively, and at last follow-up to note changes in the apex of the primary curve. Also noted were the development of adjacent compensatory curves, the overall vertical spinal growth, and the need for definitive spinal fusion once skeletal maturity was reached. Of the 21 patients, the curve apex migrated caudally in 12 patients (57%) and cephalad in 1 patient (5%), with a mean migration of 2.7 vertebral levels. Two patients (10%) developed new, significant compensatory curves (1 caudal and 1 cephalad). All patients demonstrated spinal growth in T1-S1 length following index surgery (mean, 45 mm). At skeletal maturity, 10 patients underwent definitive posterior spinal fusion and instrumentation, and 3 underwent implant removal alone. This study constitutes the longest follow-up of Shilla patients evaluating curve and implant behavior. Results of this review suggest that the apex of the fused primary curve shifts in approximately 62% of patients, with nearly all of these (92%) involving a distal migration. Compensatory curves did develop after Shilla placement as well. Overall, these findings represent adding-on distal to the apex after Shilla instrumentation rather than a crankshaft phenomenon about the apex. A better understanding of spinal growth mechanics and outcomes after Shilla placement may improve our ability to appropriately select patients and instrumentation levels. Level III.

  19. Compensatory immigration depends on adjacent population size and habitat quality but not on landscape connectivity.

    PubMed

    Turgeon, Katrine; Kramer, Donald L

    2012-11-01

    1. Populations experiencing localized mortality can recover in the short term by net movement of individuals from adjacent areas, a process called compensatory immigration or spillover. Little is known about the factors influencing the magnitude of compensatory immigration or its impact on source populations. Such information is important for understanding metapopulation dynamics, the use of protected areas for conservation, management of exploited populations and pest control. 2. Using two small, territorial damselfish species (Stegastes diencaeus and S. adustus) in their naturally fragmented habitat, we quantified compensatory immigration in response to localized mortality, assessed its impact on adjacent source populations and examined the importance of potential immigrants, habitat quality and landscape connectivity as limiting factors. On seven experimental sites, we repeatedly removed 15% of the initial population size until none remained and immigration ceased. 3. Immigrants replaced 16-72% of original residents in S. diencaeus and 0-69% in S. adustus. The proportion of the source population that immigrated into depleted areas varied from 9% to 61% in S. diencaeus and from 3% to 21% in S. adustus. In S. diencaeus, compensatory immigration was strongly affected by habitat quality, to a lesser extent by the abundance of potential immigrants and not by landscape connectivity. In S. adustus, immigration was strongly affected by the density of potential migrants and not by habitat quality and landscape connectivity. On two control sites, immigration in the absence of creation of vacancies was extremely rare. 4. Immigration occurred in response to localized mortality and was therefore compensatory. It was highly variable, sometimes producing substantial impacts on both depleted and source populations. The magnitude of compensatory immigration was influenced primarily by the availability of immigrants and by the potential improvement in territory quality that they could achieve by immigrating and not by their ability to reach the depleted area. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.

  20. Identifying compensatory driving behavior among older adults using the situational avoidance questionnaire.

    PubMed

    Davis, Jessica J; Conlon, Elizabeth G

    2017-12-01

    Driving self-regulation is considered a means through which older drivers can compensate for perceived declines in driving skill or more general feelings of discomfort on the road. One form of driving self-regulation is situational avoidance, the purposeful avoidance of situations perceived as challenging or potentially hazardous. This study aimed to validate the Situational Avoidance Questionnaire (SAQ, Davis, Conlon, Ownsworth, & Morrissey, 2016) and identify the point on the scale at which drivers practicing compensatory avoidance behavior could be distinguished from those whose driving is unrestricted, or who are avoiding situations for other, non-compensatory reasons (e.g., time or convenience). Seventy-nine Australian drivers (M age =71.48, SD=7.16, range: 55 to 86years) completed the SAQ and were classified as a compensatory-restricted or a non-restricted driver based on a semi-structured interview designed to assess the motivations underlying avoidance behavior reported on the SAQ. Using receiver-operator characteristic (ROC) analysis, the SAQ was found to have high diagnostic accuracy (sensitivity: 85%, specificity: 82%) in correctly classifying the driver groups. Group comparisons confirmed that compensatory-restricted drivers were self-regulating their driving behavior to reduce the perceived demands of the driving task. This group had, on average, slower hazard perception reaction times, and reported greater difficulty with driving, more discomfort when driving due to difficulty with hazard perception skills, and greater changes in cognition over the past five years. The SAQ is a psychometrically sound measure of situational avoidance for drivers in baby boomer and older adult generations. Use of validated measures of driving self-regulation that distinguish between compensatory and non-compensatory behavior, such as the SAQ, will advance our understanding of the driving self-regulation construct and its potential safety benefits for older road users. Copyright © 2017 National Safety Council and Elsevier Ltd. All rights reserved.

  1. Selecting decision strategies: the differential role of affect.

    PubMed

    Scheibehenne, Benjamin; von Helversen, Bettina

    2015-01-01

    Many theories on cognition assume that people adapt their decision strategies depending on the situation they face. To test if and how affect guides the selection of decision strategies, we conducted an online study (N = 166), where different mood states were induced through video clips. Results indicate that mood influenced the use of decision strategies. Negative mood, in particular anger, facilitated the use of non-compensatory strategies, whereas positive mood promoted compensatory decision rules. These results are in line with the idea that positive mood broadens the focus of attention and thus increases the use of compensatory decision strategies that take many pieces of information into account, whereas negative mood narrows the focus of attention and thus fosters non-compensatory strategies that rely on a selective use of information. The results further indicate that gaining a deeper theoretical understanding of the cognitive mechanisms that govern decision processes requires taking emotions into account.

  2. Stochastic and compensatory effects limit persistence of variation in body mass of young caribou

    USGS Publications Warehouse

    Dale, Bruce W.; Adams, Layne G.; Collins, William B.; Joly, Kyle; Valkenburg, Patrick; Tobey, Robert

    2008-01-01

    Nutritional restriction during growth can have short- and long-term effects on fitness; however, animals inhabiting uncertain environments may exhibit adaptations to cope with variation in food availability. We examined changes in body mass in free-ranging female caribou (Rangifer tarandus) by measuring mass at birth and at 4, 11, and 16 months of age to evaluate the relative importance of seasonal nutrition to growth, the persistence of cohort-specific variation in body mass through time, and compensatory growth of individuals. Relative mean body mass of cohorts did not persist through time. Compensatory growth of smaller individuals was not observed in summer; however, small calves exhibited more positive change in body mass than did large calves. Compensation occurred during periods of nutritional restriction (winter) rather than during periods of rapid growth (summer) thus differing from the conventional view of compensatory growth.

  3. Exit, voice, and disappointment: mountain decline and EU compensatory rural policy in Spain.

    PubMed

    Collantes, Fernando

    2010-01-01

    The article analyses the Spanish experience of EU compensatory rural policy in order to contribute to broader debates on the effectiveness of this kind of policy and the role of agriculture in the definition of European rural policies. In the case of Spain, compensatory allowances to mainly mountain farmers had little effect on economic trajectories or social cohesion because of the small sums involved, the exclusion of those with very small farms, and the decreasing role of agriculture in the rural economy. Other, more structural, instruments of rural policy focused on small-scale promotion of business growth but were ill-equipped to challenge some of the territorially defined items of living standard gaps. A historically grounded analysis suggests that the main changes in the social trajectory of Spain's mountain areas in the last decades have little to do with compensatory policy and are related to ordinary economic dynamics.

  4. Protective and compensatory factors mitigating the influence of deviant friends on delinquent behaviours during early adolescence.

    PubMed

    Fergusson, David M; Vitaro, Frank; Wanner, Brigitte; Brendgen, Mara

    2007-02-01

    This study examined factors that could moderate or compensate the link between exposure to deviant friends and delinquent behaviours in a sample of 265 early adolescents. The putative moderating or compensatory factors referred to the behavioural domain (i.e. novelty seeking, harm avoidance), the biological domain (i.e. physical maturation), the sociofamily domain (i.e. sociofamily adversity, parental practices), the school domain (i.e. academic performance), and the social domain (i.e. peer acceptance). A series of regression analyses showed that novelty seeking and puberty status moderated the link between friends' self-reported delinquency and participants' self-reported delinquency. In addition, all the factors except peer acceptance also had main effects that, cumulatively, reduced the association between friends' delinquency and self-rated delinquency through compensatory main effects. These results are discussed in light of the differential roles of moderating and of compensatory factors.

  5. Degeneration and domestication of a selfish gene in yeast: molecular evolution versus site-directed mutagenesis.

    PubMed

    Koufopanou, Vassiliki; Burt, Austin

    2005-07-01

    VDE is a homing endonuclease gene in yeasts with an unusual evolutionary history including horizontal transmission, degeneration, and domestication into the mating-type switching locus HO. We investigate here the effects of these features on its molecular evolution. In addition, we correlate rates of evolution with results from site-directed mutagenesis studies. Functional elements have lower rates of evolution than degenerate ones and higher conservation at functionally important sites. However, functionally important and unimportant sites are equally likely to have been involved in the evolution of new function during the domestication of VDE into HO. The domestication event also indicates that VDE has been lost in some species and that VDE has been present in yeasts for more than 50 Myr.

  6. Cognitive compensatory processes of older, clinically fit patients with hematologic malignancies undergoing chemotherapy: A longitudinal cohort study.

    PubMed

    Libert, Yves; Borghgraef, Cindy; Beguin, Yves; Delvaux, Nicole; Devos, Martine; Doyen, Chantal; Dubruille, Stéphanie; Etienne, Anne-Marie; Liénard, Aurore; Merckaert, Isabelle; Reynaert, Christine; Slachmuylder, Jean-Louis; Straetmans, Nicole; Van Den Neste, Eric; Bron, Dominique; Razavi, Darius

    2017-12-01

    Despite the well-known negative impacts of cancer and anticancer therapies on cognitive performance, little is known about the cognitive compensatory processes of older patients with cancer. This study was designed to investigate the cognitive compensatory processes of older, clinically fit patients with hematologic malignancies undergoing chemotherapy. We assessed 89 consecutive patients (age ≥ 65 y) without severe cognitive impairment and 89 age-, sex-, and education level-matched healthy controls. Cognitive compensatory processes were investigated by (1) comparing cognitive performance of patients and healthy controls in novel (first exposure to cognitive tasks) and non-novel (second exposure to the same cognitive tasks) contexts, and (2) assessing psychological factors that may facilitate or inhibit cognitive performance, such as motivation, psychological distress, and perceived cognitive performance. We assessed cognitive performance with the Trail-Making, Digit Span and FCSR-IR tests, psychological distress with the Hospital Anxiety and Depression Scale, and perceived cognitive performance with the FACT-Cog questionnaire. In novel and non-novel contexts, average cognitive performances of healthy controls were higher than those of patients and were associated with motivation. Cognitive performance of patients was not associated with investigated psychological factors in the novel context but was associated with motivation and psychological distress in the non-novel context. Older, clinically fit patients with hematologic malignancies undergoing chemotherapy demonstrated lower cognitive compensatory processes compared to healthy controls. Reducing distress and increasing motivation may improve cognitive compensatory processes of patients in non-novel contexts. Copyright © 2017 John Wiley & Sons, Ltd.

  7. Training Rapid Stepping Responses in an Individual With Stroke

    PubMed Central

    Inness, Elizabeth L.; Komar, Janice; Biasin, Louis; Brunton, Karen; Lakhani, Bimal; McIlroy, William E.

    2011-01-01

    Background and Purpose Compensatory stepping reactions are important responses to prevent a fall following a postural perturbation. People with hemiparesis following a stroke show delayed initiation and execution of stepping reactions and often are found to be unable to initiate these steps with the more-affected limb. This case report describes a targeted training program involving repeated postural perturbations to improve control of compensatory stepping in an individual with stroke. Case Description Compensatory stepping reactions of a 68-year-old man were examined 52 days after left hemorrhagic stroke. He required assistance to prevent a fall in all trials administered during his initial examination because he showed weight-bearing asymmetry (with more weight borne on the more-affected right side), was unable to initiate stepping with the right leg (despite blocking of the left leg in some trials), and demonstrated delayed response times. The patient completed 6 perturbation training sessions (30–60 minutes per session) that aimed to improve preperturbation weight-bearing symmetry, to encourage stepping with the right limb, and to reduce step initiation and completion times. Outcomes Improved efficacy of compensatory stepping reactions with training and reduced reliance on assistance to prevent falling were observed. Improvements were noted in preperturbation asymmetry and step timing. Blocking the left foot was effective in encouraging stepping with the more-affected right foot. Discussion This case report demonstrates potential short-term adaptations in compensatory stepping reactions following perturbation training in an individual with stroke. Future work should investigate the links between improved compensatory step characteristics and fall risk in this vulnerable population. PMID:21511992

  8. Anticipatory postural adjustments contribute to age-related changes in compensatory steps associated with unilateral perturbations.

    PubMed

    Hyodo, Masaki; Saito, Mayumi; Ushiba, Junichi; Tomita, Yutaka; Minami, Mihoko; Masakado, Yoshihisa

    2012-07-01

    Compensatory steps are essential for preventing falls following perturbations. This study aimed to explore age-related changes in compensatory steps to unilateral perturbations, specifically in terms of whether anticipatory postural adjustments (APAs) play a role in stabilizing lateral balance. Five young and five elderly male adults participated. The split-belt treadmill was used to provide bi- and unilateral perturbations, as forward or backward transitions, applied 10 times in random order. Backward steps evoked by unilateral forward perturbations were evaluated. We measured temporal characteristics, mediolateral (ML) center of mass (COM) motion, and ML step length of compensatory steps. Compensatory steps to unexpected perturbations showed delayed onset of foot-off (FO) and expanded lateral swing length in elderly compared to young subjects. Differences in COM motions and step width arose related to APAs. Elderly subjects showing APAs exhibited no significant differences in ML COM, ML COM velocity, or ML swing length compared to young subjects. However, elderly subjects without APAs showed significant changes toward instability in these parameters. The fact that APAs play a notable role, particularly in the elderly, in stability offers a new insight into preventing falls. However, APAs occurred in 29% of the steps of young and 35% of the steps of elderly subjects. If the occurrence of APAs in elderly people in response to compensatory steps was more frequent, fall risk would be reduced. Further studies, particularly into APA frequency, might contribute to improved intervention to prevent falls. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. EVOLUTIONARY FOUNDATIONS FOR MOLECULAR MEDICINE

    PubMed Central

    Nesse, Randolph M.; Ganten, Detlev; Gregory, T. Ryan; Omenn, Gilbert S.

    2015-01-01

    Evolution has long provided a foundation for population genetics, but many major advances in evolutionary biology from the 20th century are only now being applied in molecular medicine. They include the distinction between proximate and evolutionary explanations, kin selection, evolutionary models for cooperation, and new strategies for tracing phylogenies and identifying signals of selection. Recent advances in genomics are further transforming evolutionary biology and creating yet more opportunities for progress at the interface of evolution with genetics, medicine, and public health. This article reviews 15 evolutionary principles and their applications in molecular medicine in hopes that readers will use them and others to speed the development of evolutionary molecular medicine. PMID:22544168

  10. Compensatory Evolution of Intrinsic Transcription Terminators in Bacillus Cereus

    PubMed Central

    Safina, Ksenia R.; Mironov, Andrey A.

    2017-01-01

    Many RNA molecules possess complicated secondary structure critical to their function. Mutations in double-helical regions of RNA may disrupt Watson–Crick (WC) interactions causing structure destabilization or even complete loss of function. Such disruption can be compensated by another mutation restoring base pairing, as has been shown for mRNA, rRNA and tRNA. Here, we investigate the evolution of intrinsic transcription terminators between closely related strains of Bacillus cereus. While the terminator structure is maintained by strong natural selection, as evidenced by the low frequency of disrupting mutations, we observe multiple instances of pairs of disrupting-compensating mutations in RNA structure stems. Such two-step switches between different WC pairs occur very fast, consistent with the low fitness conferred by the intermediate non-WC variant. Still, they are not instantaneous, and probably involve transient fixation of the intermediate variant. The GU wobble pair is the most frequent intermediate, and remains fixed longer than other intermediates, consistent with its less disruptive effect on the RNA structure. Double switches involving non-GU intermediates are more frequent at the ends of RNA stems, probably because they are associated with smaller fitness loss. Together, these results show that the fitness landscape of bacterial transcription terminators is rather rugged, but that the fitness valleys associated with unpaired stem nucleotides are rather shallow, facilitating evolution. PMID:28201729

  11. Size uniformity of animal cells is actively maintained by a p38 MAPK-dependent regulation of G1-length.

    PubMed

    Liu, Shixuan; Ginzberg, Miriam Bracha; Patel, Nish; Hild, Marc; Leung, Bosco; Li, Zhengda; Chen, Yen-Chi; Chang, Nancy; Wang, Yuan; Tan, Ceryl; Diena, Shulamit; Trimble, William; Wasserman, Larry; Jenkins, Jeremy L; Kirschner, Marc W; Kafri, Ran

    2018-03-29

    Animal cells within a tissue typically display a striking regularity in their size. To date, the molecular mechanisms that control this uniformity are still unknown. We have previously shown that size uniformity in animal cells is promoted, in part, by size-dependent regulation of G1 length. To identify the molecular mechanisms underlying this process, we performed a large-scale small molecule screen and found that the p38 MAPK pathway is involved in coordinating cell size and cell cycle progression. Small cells display higher p38 activity and spend more time in G1 than larger cells. Inhibition of p38 MAPK leads to loss of the compensatory G1 length extension in small cells, resulting in faster proliferation, smaller cell size and increased size heterogeneity. We propose a model wherein the p38 pathway responds to changes in cell size and regulates G1 exit accordingly, to increase cell size uniformity. © 2017, Liu et al.

  12. Molecular changes in brain aging and Alzheimer’s disease are mirrored in experimentally silenced cortical neuron networks

    PubMed Central

    Gleichmann, Marc; Zhang, Yongqing; Wood, William H.; Becker, Kevin G.; Mughal, Mohamed R.; Pazin, Michael J.; van Praag, Henriette; Kobilo, Tali; Zonderman, Alan B.; Troncoso, Juan C.; Markesbery, William R.; Mattson, Mark P.

    2010-01-01

    Activity-dependent modulation of neuronal gene expression promotes neuronal survival and plasticity, and neuronal network activity is perturbed in aging and Alzheimer’s disease (AD). Here we show that cerebral cortical neurons respond to chronic suppression of excitability by downregulating the expression of genes and their encoded proteins involved in inhibitory transmission (GABAergic and somatostatin) and Ca2+ signaling; alterations in pathways involved in lipid metabolism and energy management are also features of silenced neuronal networks. A molecular fingerprint strikingly similar to that of diminished network activity occurs in the human brain during aging and in AD, and opposite changes occur in response to activation of N-methyl-D-aspartate (NMDA) and brain-derived neurotrophic factor (BDNF) receptors in cultured cortical neurons and in mice in response to an enriched environment or electroconvulsive shock. Our findings suggest that reduced inhibitory neurotransmission during aging and in AD may be the result of compensatory responses that, paradoxically, render the neurons vulnerable to Ca2+-mediated degeneration. PMID:20947216

  13. Compensatory Mitigation Site Protection Instrument Handbook and Fact Sheet

    EPA Pesticide Factsheets

    The site protection instrument is a written description of the legal arrangements including site ownership, management, and enforcement of any use restrictions that will be used to ensure the long-term protection of the compensatory mitigation project site

  14. COMPENSATORY CHANGES IN THE HIPPOCAMPUS FOLLOWING INTRADENTATE INFUSION OF COLCHICINE

    EPA Science Inventory

    Direct infusion of colchicine into the dentate gyrus of the hippocampus kills granule cells and elicits compensatory behavioral, neurochemical and neuroanatomical changes. olchicine-treated rats are less sensitive to the behavioral effects of cholinergic muscarinic receptor antag...

  15. Federal Register Notice Compensatory Mitigation Rule

    EPA Pesticide Factsheets

    EPA and the U.S. Army Corps of Engineers (the Corps) announced proposed revisions to regulations governing compensatory mitigation for authorized impacts to wetlands, streams, and other waters of the U.S. under Section 404 of the Clean Water Act.

  16. The efficacy of prospective memory rehabilitation plus metacognitive skills training for adults with traumatic brain injury: study protocol for a randomized controlled trial.

    PubMed

    Fleming, Jennifer; Ownsworth, Tamara; Doig, Emmah; Hutton, Lauren; Griffin, Janelle; Kendall, Melissa; Shum, David H K

    2017-01-05

    Impairment of prospective memory (PM) is common following traumatic brain injury (TBI) and negatively impacts on independent living. Compensatory approaches to PM rehabilitation have been found to minimize the impact of PM impairment in adults with TBI; however, poor self-awareness after TBI poses a major barrier to the generalization of compensatory strategies in daily life. Metacognitive skills training (MST) is a cognitive rehabilitation approach that aims to facilitate the development of self-awareness in adults with TBI. This paper describes the protocol of a study that aims to evaluate the efficacy of a MST approach to compensatory PM rehabilitation for improving everyday PM performance and psychosocial outcomes after TBI. This randomized controlled trial has three treatment groups: compensatory training plus metacognitive skills training (COMP-MST), compensatory training only (COMP), and waitlist control. Participants in the COMP-MST and COMP groups will complete a 6-week intervention consisting of six 2-h weekly training sessions. Each 1.5-h session will involve compensatory strategy training and 0.5 h will incorporate either MST (COMP-MST group) or filler activity as an active control (COMP group). Participants in the waitlist group receive care as usual for 6 weeks, followed by the COMP-MST intervention. Based on the sample size estimate, 90 participants with moderate to severe TBI will be randomized into the three groups using a stratified sampling approach. The primary outcomes include measures of PM performance in everyday life and level of psychosocial reintegration. Secondary outcomes include measures of PM function on psychometric testing, strategy use, self-awareness, and level of support needs following TBI. Blinded assessments will be conducted pre and post intervention, and at 3-month and 6-month follow-ups. This study seeks to determine the efficacy of COMP-MST for improving and maintaining everyday PM performance and level of psychosocial integration in adults with moderate to severe TBI. The findings will advance theoretical understanding of the role of self-awareness in compensatory PM rehabilitation and skills generalization. COMP-MST has the potential to reduce the cost of rehabilitation and lifestyle support following TBI because the intervention could enhance generalization success and lifelong application of PM compensatory strategies. New Zealand Clinical Trials Registry, ACTRN12615000996561 . Registered on 23 September 2015; retrospectively registered 2 months after commencement.

  17. Radiobiological modeling with MarCell software

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hasan, J.S.; Jones, T.D.

    1999-01-01

    A nonlinear system of differential equations that models the bone marrow cellular kinetics associated with radiation injury, molecular repair, and compensatory cell proliferation has been extensively documented. Recently, that model has been implemented as MarCell, a user-friendly MS-DOS computer program that allows users with little knowledge of the original model to evaluate complex radiation exposure scenarios. The software allows modeling with the following radiations: tritium beta, 100 kVp X, 250 kVp X, 22 MV X, {sup 60}Co, {sup 137}Cs, 2 MeV electrons, triga neutrons, D-T neutrons, and 3 blends of mixed-field fission radiations. The possible cell lineages are stem, stroma,more » and leukemia/lymphoma, and the available species include mouse, rat, dog, sheep, swine, burro, and man. An attractive mathematical feature is that any protracted protocol can be expressed as an equivalent prompt dose for either the source used or for a reference, such as 250 kVp X rays or {sup 60}Co. Output from MarCell includes: risk of 30-day mortality; risk of cancer and leukemia based either on cytopenia or compensatory cell proliferation; cell survival plots as a function of time or dose; and 4-week recovery kinetics following treatment. In this article, the program`s applicability and ease of use are demonstrated by evaluating a medical total body irradiation protocol and a nuclear fallout scenario.« less

  18. Compound heterozygosity for two GHR missense mutations in a patient affected by Laron Syndrome: a case report.

    PubMed

    Moia, Stefania; Tessaris, Daniele; Einaudi, Silvia; de Sanctis, Luisa; Bona, Gianni; Bellone, Simonetta; Prodam, Flavia

    2017-10-12

    Mutations localized in the Growth Hormone Receptor (GHR) gene are often associated with the pathogenesis of Laron Syndrome, an autosomal recessive hereditary disorder characterized by severe growth retardation. Biochemically, patients present normal to high circulating GH levels, in presence of very low or undetectable IGF-I levels, which do not rise after rhGH treatment. We describe the case of a 3.8 years old girl with symmetrical short stature (-3.76 SDS), low IGF-1 and IGFBP-3, in presence of normal GH levels. Parents were not relatives and there was no family history of short stature. During the second day of birth, she developed severe hypoglycaemia that required glucose infusion. She presented frontal bossing and depressed nasal bridge. IGF-1 generation test showed no response, suggesting a GH resistance evidence. In the hypothesis of Laron Syndrome, we decided to perform a molecular analysis of Growth Hormone Receptor (GHR) gene. This analysis demonstrated that the patient was compound heterozygote for two missense mutations. GHR gene mutations are a well demonstrated cause of GH insensitivity. In heterozygous patients, probably the normal stature may be achieved by a compensatory mechanism of GH secretion or signalling. On the contrary, in homozygous or compound heterozygous patients these compensatory mechanisms are inadequate, and short stature may be the consequence.

  19. Molecular evolution of cyclin proteins in animals and fungi

    PubMed Central

    2011-01-01

    Background The passage through the cell cycle is controlled by complexes of cyclins, the regulatory units, with cyclin-dependent kinases, the catalytic units. It is also known that cyclins form several families, which differ considerably in primary structure from one eukaryotic organism to another. Despite these lines of evidence, the relationship between the evolution of cyclins and their function is an open issue. Here we present the results of our study on the molecular evolution of A-, B-, D-, E-type cyclin proteins in animals and fungi. Results We constructed phylogenetic trees for these proteins, their ancestral sequences and analyzed patterns of amino acid replacements. The analysis of infrequently fixed atypical amino acid replacements in cyclins evidenced that accelerated evolution proceeded predominantly during paralog duplication or after it in animals and fungi and that it was related to aromorphic changes in animals. It was shown also that evolutionary flexibility of cyclin function may be provided by consequential reorganization of regions on protein surface remote from CDK binding sites in animal and fungal cyclins and by functional differentiation of paralogous cyclins formed in animal evolution. Conclusions The results suggested that changes in the number and/or nature of cyclin-binding proteins may underlie the evolutionary role of the alterations in the molecular structure of cyclins and their involvement in diverse molecular-genetic events. PMID:21798004

  20. Molecular Evolution of Respiratory Syncytial Virus Fusion Gene, Canada, 2006–2010

    PubMed Central

    Papenburg, Jesse; Carbonneau, Julie; Hamelin, Marie-Ève; Isabel, Sandra; Bouhy, Xavier; Ohoumanne, Najwa; Déry, Pierre; Paes, Bosco A.; Corbeil, Jacques; Bergeron, Michel G.; De Serres, Gaston

    2012-01-01

    To assess molecular evolution of the respiratory syncytial virus (RSV) fusion gene, we analyzed RSV-positive specimens from 123 children in Canada who did or did not receive RSV immunoprophylaxis (palivizumab) during 2006–2010. Resistance-conferring mutations within the palivizumab binding site occurred in 8.7% of palivizumab recipients and none of the nonrecipients. PMID:22264682

  1. Integrated Multiscale Modeling of Molecular Computing Devices. Final Report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tim Schulze

    2012-11-01

    The general theme of this research has been to expand the capabilities of a simulation technique, Kinetic Monte Carlo (KMC) and apply it to study self-assembled nano-structures on epitaxial thin films. KMC simulates thin film growth and evolution by replacing the detailed dynamics of the system's evolution, which might otherwise be studied using molecular dynamics, with an appropriate stochastic process.

  2. Changes in Diversification Patterns and Signatures of Selection during the Evolution of Murinae-Associated Hantaviruses

    PubMed Central

    Castel, Guillaume; Razzauti, Maria; Jousselin, Emmanuelle; Kergoat, Gael J.; Cosson, Jean-François

    2014-01-01

    In the last 50 years, hantaviruses have significantly affected public health worldwide, but the exact extent of the distribution of hantavirus diseases, species and lineages and the risk of their emergence into new geographic areas are still poorly known. In particular, the determinants of molecular evolution of hantaviruses circulating in different geographical areas or different host species are poorly documented. Yet, this understanding is essential for the establishment of more accurate scenarios of hantavirus emergence under different climatic and environmental constraints. In this study, we focused on Murinae-associated hantaviruses (mainly Seoul Dobrava and Hantaan virus) using sequences available in GenBank and conducted several complementary phylogenetic inferences. We sought for signatures of selection and changes in patterns and rates of diversification in order to characterize hantaviruses’ molecular evolution at different geographical scales (global and local). We then investigated whether these events were localized in particular geographic areas. Our phylogenetic analyses supported the assumption that RNA virus molecular variations were under strong evolutionary constraints and revealed changes in patterns of diversification during the evolutionary history of hantaviruses. These analyses provide new knowledge on the molecular evolution of hantaviruses at different scales of time and space. PMID:24618811

  3. Stretch or contraction induced inversion of rectification in diblock molecular junctions

    NASA Astrophysics Data System (ADS)

    Zhang, Guang-Ping; Hu, Gui-Chao; Song, Yang; Xie, Zhen; Wang, Chuan-Kui

    2013-09-01

    Based on ab initio theory and nonequilibrium Green's function method, the effect of stretch or contraction on the rectification in diblock co-oligomer molecular diodes is investigated theoretically. Interestingly, an inversion of rectifying direction induced by stretching or contracting the molecular junctions, which is closely related to the number of the pyrimidinyl-phenyl units, is proposed. The analysis of the molecular projected self-consistent Hamiltonian and the evolution of the frontier molecular orbitals as well as transmission coefficients under external biases gives an inside view of the observed results. It reveals that the asymmetric molecular level shift and asymmetric evolution of orbital wave functions under biases are competitive mechanisms for rectification. The stretching or contracting induced inversion of the rectification is due to the conversion of the dominant mechanism. This work suggests a feasible technique to manipulate the rectification performance in molecular diodes by use of the mechanically controllable method.

  4. Convergent and correlated evolution of major life-history traits in the angiosperm genus Leucadendron (Proteaceae).

    PubMed

    Tonnabel, Jeanne; Mignot, Agnès; Douzery, Emmanuel J P; Rebelo, Anthony G; Schurr, Frank M; Midgley, Jeremy; Illing, Nicola; Justy, Fabienne; Orcel, Denis; Olivieri, Isabelle

    2014-10-01

    Natural selection is expected to cause convergence of life histories among taxa as well as correlated evolution of different life-history traits. Here, we quantify the extent of convergence of five key life-history traits (adult fire survival, seed storage, degree of sexual dimorphism, pollination mode, and seed-dispersal mode) and test hypotheses about their correlated evolution in the genus Leucadendron (Proteaceae) from the fire-prone South African fynbos. We reconstructed a new molecular phylogeny of this highly diverse genus that involves more taxa and molecular markers than previously. This reconstruction identifies new clades that were not detected by previous molecular study and morphological classifications. Using this new phylogeny and robust methods that account for phylogenetic uncertainty, we show that the five life-history traits studied were labile during the evolutionary history of the genus. This diversity allowed us to tackle major questions about the correlated evolution of life-history strategies. We found that species with longer seed-dispersal distances tended to evolve lower pollen-dispersal distance, that insect-pollinated species evolved decreased sexual dimorphism, and that species with a persistent soil seed-bank evolved toward reduced fire-survival ability of adults. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  5. Molecular mechanisms of dominance evolution in Müllerian mimicry.

    PubMed

    Llaurens, V; Joron, M; Billiard, S

    2015-12-01

    Natural selection acting on dominance between adaptive alleles at polymorphic loci can be sufficiently strong for dominance to evolve. However, the molecular mechanisms underlying such evolution are generally unknown. Here, using Müllerian mimicry as a case-study for adaptive morphological variation, we present a theoretical analysis of the invasion of dominance modifiers altering gene expression through different molecular mechanisms. Toxic species involved in Müllerian mimicry exhibit warning coloration, and converge morphologically with other toxic species of the local community, due to positive frequency-dependent selection acting on these colorations. Polymorphism in warning coloration may be maintained by migration-selection balance with fine scale spatial heterogeneity. We modeled a dominance modifier locus altering the expression of the warning coloration locus, targeting one or several alleles, acting in cis or trans, and either enhancing or repressing expression. We confirmed that dominance could evolve when balanced polymorphism was maintained at the color locus. Dominance evolution could result from modifiers enhancing one allele specifically, irrespective of their linkage with the targeted locus. Nonspecific enhancers could also persist in populations, at frequencies tightly depending on their linkage with the targeted locus. Altogether, our results identify which mechanisms of expression alteration could lead to dominance evolution in polymorphic mimicry. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  6. Fourth Symposium on Chemical Evolution and the Origin and Evolution of Life

    NASA Technical Reports Server (NTRS)

    Wharton, Robert A., Jr. (Editor); Andersen, Dale T. (Editor); Bzik, Sara E. (Editor); Rummel, John D. (Editor)

    1991-01-01

    This symposium was held at the NASA Ames Research Center, Moffett Field, California, July 24-27, 1990. The NASA exobiology investigators reported their recent research findings. Scientific papers were presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI).

  7. Molecular clocks and the early evolution of metazoan nervous systems.

    PubMed

    Wray, Gregory A

    2015-12-19

    The timing of early animal evolution remains poorly resolved, yet remains critical for understanding nervous system evolution. Methods for estimating divergence times from sequence data have improved considerably, providing a more refined understanding of key divergences. The best molecular estimates point to the origin of metazoans and bilaterians tens to hundreds of millions of years earlier than their first appearances in the fossil record. Both the molecular and fossil records are compatible, however, with the possibility of tiny, unskeletonized, low energy budget animals during the Proterozoic that had planktonic, benthic, or meiofaunal lifestyles. Such animals would likely have had relatively simple nervous systems equipped primarily to detect food, avoid inhospitable environments and locate mates. The appearance of the first macropredators during the Cambrian would have changed the selective landscape dramatically, likely driving the evolution of complex sense organs, sophisticated sensory processing systems, and diverse effector systems involved in capturing prey and avoiding predation. © 2015 The Author(s).

  8. Linear motif-mediated interactions have contributed to the evolution of modularity in complex protein interaction networks.

    PubMed

    Kim, Inhae; Lee, Heetak; Han, Seong Kyu; Kim, Sanguk

    2014-10-01

    The modular architecture of protein-protein interaction (PPI) networks is evident in diverse species with a wide range of complexity. However, the molecular components that lead to the evolution of modularity in PPI networks have not been clearly identified. Here, we show that weak domain-linear motif interactions (DLIs) are more likely to connect different biological modules than strong domain-domain interactions (DDIs). This molecular division of labor is essential for the evolution of modularity in the complex PPI networks of diverse eukaryotic species. In particular, DLIs may compensate for the reduction in module boundaries that originate from increased connections between different modules in complex PPI networks. In addition, we show that the identification of biological modules can be greatly improved by including molecular characteristics of protein interactions. Our findings suggest that transient interactions have played a unique role in shaping the architecture and modularity of biological networks over the course of evolution.

  9. Epigenetics and sex-specific fitness: an experimental test using male-limited evolution in Drosophila melanogaster.

    PubMed

    Abbott, Jessica K; Innocenti, Paolo; Chippindale, Adam K; Morrow, Edward H

    2013-01-01

    When males and females have different fitness optima for the same trait but share loci, intralocus sexual conflict is likely to occur. Epigenetic mechanisms such as genomic imprinting (in which expression is altered according to parent-of-origin) and sex-specific maternal effects have been suggested as ways by which this conflict can be resolved. However these ideas have not yet been empirically tested. We designed an experimental evolution protocol in Drosophila melanogaster that enabled us to look for epigenetic effects on the X-chromosome-a hotspot for sexually antagonistic loci. We used special compound-X females to enforce father-to-son transmission of the X-chromosome for many generations, and compared fitness and gene expression levels between Control males, males with a Control X-chromosome that had undergone one generation of father-son transmission, and males with an X-chromosome that had undergone many generations of father-son transmission. Fitness differences were dramatic, with experimentally-evolved males approximately 20% greater than controls, and with males inheriting a non-evolved X from their father about 20% lower than controls. These data are consistent with both strong intralocus sexual conflict and misimprinting of the X-chromosome under paternal inheritance. However, expression differences suggested that reduced fitness under paternal X inheritance was largely due to deleterious maternal effects. Our data confirm the sexually-antagonistic nature of Drosophila's X-chromosome and suggest that the response to male-limited X-chromosome evolution entails compensatory evolution for maternal effects, and perhaps modification of other epigenetic effects via coevolution of the sex chromosomes.

  10. Molecular Epidemiology and Genomics of Group A Streptococcus

    PubMed Central

    Bessen, Debra E.; McShan, W. Michael; Nguyen, Scott V.; Shetty, Amol; Agrawal, Sonia; Tettelin, Hervé

    2014-01-01

    Streptococcus pyogenes (group A streptococcus; GAS) is a strict human pathogen with a very high prevalence worldwide. This review highlights the genetic organization of the species and the important ecological considerations that impact its evolution. Recent advances are presented on the topics of molecular epidemiology, population biology, molecular basis for genetic change, genome structure and genetic flux, phylogenomics and closely related streptococcal species, and the long- and short-term evolution of GAS. The application of whole genome sequence data to addressing key biological questions is discussed. PMID:25460818

  11. Notification: Review of Religious Compensatory Time

    EPA Pesticide Factsheets

    Project #OA-FY15-0180, August 5, 2015. The Office of Inspector General (OIG) for the U.S. Environmental Protection Agency (EPA) plans to begin field work on our audit of the EPA’s practices, policies and procedures for religious compensatory time.

  12. An Assessment Framework for Making Compensatory Mitigation Determinations in California

    EPA Science Inventory

    Efficient gathering and use of assessment information will improve the ecological effectiveness of compensatory mitigation. It also will make for more efficient regulatory decision-making. Recognizing these facts, the California Water Board worked in collaboration with the USEPA...

  13. The compensatory motion of wrist immobilization on thumb and index finger performance--kinematic analysis and clinical implications.

    PubMed

    Liu, Chien-Hsiou; Chiang, Hsin-Yu; Chen, Kun-Hung

    2015-01-01

    Based on the high prevalence of people with problems in the wrist and hand simultaneously, it is of its importance to clarify whether hand joints exert extra motion to compensate for wrist motion while immobilized. This study aimed to measure the compensatory movement of the thumb and index finger when people perform daily activities with an immobilized wrist. Thirty healthy volunteers were recruited in this study. A wrist splint, the Jebsen-Taylor Hand Function Test, and the OptoTrak Certus motion tracking system were used. Seven inter-digit mean joint angles of the index finger and thumb were calculated. Paired sample t-test was used. (1) The compensatory motions were noted in the Metacarpophalangeal and Carpometacarpal joints of the thumb, and the proximal interphalangeal joints of the index finger; (2) The manifestation of compensatory motion was related to type of activity performed except when picking up light and heavy cans. The compensatory motions appeared while the wrist was immobilized and were found to be disadvantageous to the progression of disease. In the future, studies need to be done to understand how to select products with correct ergonomic design to enable people to reap greater benefits from wearing wrist splints.

  14. [Effects of clipping on nitrogen allocation strategy and compensatory growth of Leymus chinensis under saline-alkali conditions].

    PubMed

    Zheng, Cong Cong; Wang, Yong Jing; Sun, Hao; Wang, Xin Yu; Gao, Ying Zhi

    2017-07-18

    Soil salinization and overgrazing are two main factors limiting animal husbandry in the Songnen Grassland. Leymus chinensis is a dominant rhizome grass, resistant to grazing as well as to-lerant to salt stress. Foliar labeled with 15 N-urea was used to study the nitrogen allocation strategy and compensatory growth response to clipping under saline-alkali conditions. The results showed that the total absorbed 15 N allocated to the aboveground part was more than 60%. Compared with the control treatment (no saline-alkali, no clipping), saline-alkali increased the distribution of 15 N by 5.1% in root; the 15 N distribution into aboveground in the moderate clipping and saline-alkali treatment was 11.6% higher than that of the control, exhibiting over-compensatory growth of aboveground biomass and total biomass, however, 15 N allocated to stem base was significantly increased by 9.5% under severe clipping level and saline-alkali addition, showing under-compensatory growth of shoot, root and total biomass. These results suggested that L. chinensis adapted to mode-rate clipping by over-compensatory growth under salt-alkali stress condition. However, L. chinensis would take a relatively conservative growth strategy through the enhanced N allocation to stem base for storage under severe saline-alkali and clipping conditions.

  15. Developmental Trajectories of Compensatory Exercise and Fasting Behavior across the Middle School Years

    PubMed Central

    Davis, Heather A.; Guller, Leila; Smith, Gregory T.

    2016-01-01

    Compensatory exercise and fasting behavior, in the absence of binge eating and purging, appear to be important eating disorder behaviors that are associated with dysfunction, but little is known about these behaviors in youth. We studied the trajectories of their development in non-binge eating and non-purging girls during early adolescence. Using a longitudinal design, we assessed 564 girls six times over the three years of middle school (grades 6 through 8) and developed trajectories specifying different developmental patterns in relation to the behaviors. Prior to this period, when the girls were in 5th grade (elementary school), we assessed risk factors to predict girls’ subsequent trajectory group membership. Compensatory exercise trajectory groups included a non-engagement group, a group that increased in the behavior, and a group that decreased in the behavior. There were two fasting trajectory groups, one consistently engaging in the behavior and the other consistently not. Elementary school levels of depression, eating expectancies, and thinness expectancies predicted subsequent trajectory group membership. Risk for compensatory exercise and fasting should be evaluated as early as in 5th grade. Targeted interventions should focus on girls in late elementary school or middle school, as this appears to be a critical developmental and maintenance period for compensatory exercise and fasting behavior. PMID:27544806

  16. Early compensatory sensory re-education.

    PubMed

    Daniele, Hugo R; Aguado, Leda

    2003-02-01

    After a neurorrhaphy, there will be a distal disconnection between the cortex and skin receptors, along with interruption of sensibility information. This report demonstrates the efficacy of a new sensory re-education program for achieving optimal sensation in a relatively short time. Between 1999 and 2001, in the authors' Hand Rehabilitation Department, 11 patients with previous neurorrhaphy were subjected to a program of early "compensatory sensory re-education." Lesions were caused by clean cut. There were 13 primary digital nerve procedures, 12 at the distal palmar MP level, and one at the radial dorsal branch of the index (just after emerging from the common digital nerve). The technique of compensatory sensory re-education was based on a previous, but modified, sensory re-education method. In order to evaluate the results in the compensatory sensory re-education series described, additional tests for evaluation of achieved functional sensibility were used. The authors' best results were achieved in a maximum of 8 weeks (4-8 weeks), much less time than with the original method (1-2 years). Using the British classification, it was possible to compare the achieved levels of sensibility and the time required for optimal results. The different methods of sensibility re-education may be similar, but with the authors' compensatory sensory re-education method, substantial time is saved.

  17. An Approach of Estimating Individual Growth Curves for Young Thoroughbred Horses Based on Their Birthdays

    PubMed Central

    ONODA, Tomoaki; YAMAMOTO, Ryuta; SAWAMURA, Kyohei; MURASE, Harutaka; NAMBO, Yasuo; INOUE, Yoshinobu; MATSUI, Akira; MIYAKE, Takeshi; HIRAI, Nobuhiro

    2014-01-01

    ABSTRACT We propose an approach of estimating individual growth curves based on the birthday information of Japanese Thoroughbred horses, with considerations of the seasonal compensatory growth that is a typical characteristic of seasonal breeding animals. The compensatory growth patterns appear during only the winter and spring seasons in the life of growing horses, and the meeting point between winter and spring depends on the birthday of each horse. We previously developed new growth curve equations for Japanese Thoroughbreds adjusting for compensatory growth. Based on the equations, a parameter denoting the birthday information was added for the modeling of the individual growth curves for each horse by shifting the meeting points in the compensatory growth periods. A total of 5,594 and 5,680 body weight and age measurements of Thoroughbred colts and fillies, respectively, and 3,770 withers height and age measurements of both sexes were used in the analyses. The results of predicted error difference and Akaike Information Criterion showed that the individual growth curves using birthday information better fit to the body weight and withers height data than not using them. The individual growth curve for each horse would be a useful tool for the feeding managements of young Japanese Thoroughbreds in compensatory growth periods. PMID:25013356

  18. Community Structure Analysis of Transcriptional Networks Reveals Distinct Molecular Pathways for Early- and Late-Onset Temporal Lobe Epilepsy with Childhood Febrile Seizures

    PubMed Central

    Moreira-Filho, Carlos Alberto; Bando, Silvia Yumi; Bertonha, Fernanda Bernardi; Iamashita, Priscila; Silva, Filipi Nascimento; Costa, Luciano da Fontoura; Silva, Alexandre Valotta; Castro, Luiz Henrique Martins; Wen, Hung-Tzu

    2015-01-01

    Age at epilepsy onset has a broad impact on brain plasticity and epilepsy pathomechanisms. Prolonged febrile seizures in early childhood (FS) constitute an initial precipitating insult (IPI) commonly associated with mesial temporal lobe epilepsy (MTLE). FS-MTLE patients may have early disease onset, i.e. just after the IPI, in early childhood, or late-onset, ranging from mid-adolescence to early adult life. The mechanisms governing early (E) or late (L) disease onset are largely unknown. In order to unveil the molecular pathways underlying E and L subtypes of FS-MTLE we investigated global gene expression in hippocampal CA3 explants of FS-MTLE patients submitted to hippocampectomy. Gene coexpression networks (GCNs) were obtained for the E and L patient groups. A network-based approach for GCN analysis was employed allowing: i) the visualization and analysis of differentially expressed (DE) and complete (CO) - all valid GO annotated transcripts - GCNs for the E and L groups; ii) the study of interactions between all the system’s constituents based on community detection and coarse-grained community structure methods. We found that the E-DE communities with strongest connection weights harbor highly connected genes mainly related to neural excitability and febrile seizures, whereas in L-DE communities these genes are not only involved in network excitability but also playing roles in other epilepsy-related processes. Inversely, in E-CO the strongly connected communities are related to compensatory pathways (seizure inhibition, neuronal survival and responses to stress conditions) while in L-CO these communities harbor several genes related to pro-epileptic effects, seizure-related mechanisms and vulnerability to epilepsy. These results fit the concept, based on fMRI and behavioral studies, that early onset epilepsies, although impacting more severely the hippocampus, are associated to compensatory mechanisms, while in late MTLE development the brain is less able to generate adaptive mechanisms, what has implications for epilepsy management and drug discovery. PMID:26011637

  19. Compensatory Hypertrophy of Skeletal Muscle: Contractile Characteristics

    ERIC Educational Resources Information Center

    Ianuzzo, C. D.; Chen, V.

    1977-01-01

    Describes an experiment using rats that demonstrates contractile characteristics of normal and hypertrophied muscle. Compensatory hypertrophy of the plantaris muscle is induced by surgical removal of the synergistic gastrocnemium muscle. Includes methods for determination of contractile properties of normal and hypertrophied muscle and…

  20. 42 CFR 136.320 - Preparatory scholarship grants.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... professions school. Examples of individuals eligible for such grants are the individual who: (a) Has completed high school equivalency and needs compensatory preprofessional education to enroll in a health professions school; (b) Has a baccalaureate degree and needs compensatory preprofessional education to qualify...

  1. 42 CFR 136.320 - Preparatory scholarship grants.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... professions school. Examples of individuals eligible for such grants are the individual who: (a) Has completed high school equivalency and needs compensatory preprofessional education to enroll in a health professions school; (b) Has a baccalaureate degree and needs compensatory preprofessional education to qualify...

  2. 42 CFR 136.320 - Preparatory scholarship grants.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... professions school. Examples of individuals eligible for such grants are the individual who: (a) Has completed high school equivalency and needs compensatory preprofessional education to enroll in a health professions school; (b) Has a baccalaureate degree and needs compensatory preprofessional education to qualify...

  3. 42 CFR 136.320 - Preparatory scholarship grants.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... professions school. Examples of individuals eligible for such grants are the individual who: (a) Has completed high school equivalency and needs compensatory preprofessional education to enroll in a health professions school; (b) Has a baccalaureate degree and needs compensatory preprofessional education to qualify...

  4. 42 CFR 136.320 - Preparatory scholarship grants.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... professions school. Examples of individuals eligible for such grants are the individual who: (a) Has completed high school equivalency and needs compensatory preprofessional education to enroll in a health professions school; (b) Has a baccalaureate degree and needs compensatory preprofessional education to qualify...

  5. Evolution and the Distribution of Glutaminyl and Asparaginyl Residues in Proteins

    PubMed Central

    Robinson, Arthur B.

    1974-01-01

    Recent experiments on the deamidation of glutaminyl and asparaginyl residues in peptides and proteins support the hypothesis that these residues may serve as molecular clocks that control biological processes. A hypothesis is now offered that suggests that these molecular clocks are set by rejection or accumulation of appropriate sequences of residues including a glutaminyl or asparaginyl residue during evolution. PMID:4522799

  6. Ecology has contrasting effects on genetic variation within species versus rates of molecular evolution across species in water beetles.

    PubMed

    Fujisawa, Tomochika; Vogler, Alfried P; Barraclough, Timothy G

    2015-01-22

    Comparative analysis is a potentially powerful approach to study the effects of ecological traits on genetic variation and rate of evolution across species. However, the lack of suitable datasets means that comparative studies of correlates of genetic traits across an entire clade have been rare. Here, we use a large DNA-barcode dataset (5062 sequences) of water beetles to test the effects of species ecology and geographical distribution on genetic variation within species and rates of molecular evolution across species. We investigated species traits predicted to influence their genetic characteristics, such as surrogate measures of species population size, latitudinal distribution and habitat types, taking phylogeny into account. Genetic variation of cytochrome oxidase I in water beetles was positively correlated with occupancy (numbers of sites of species presence) and negatively with latitude, whereas substitution rates across species depended mainly on habitat types, and running water specialists had the highest rate. These results are consistent with theoretical predictions from nearly-neutral theories of evolution, and suggest that the comparative analysis using large databases can give insights into correlates of genetic variation and molecular evolution.

  7. Effect of lungeing on head and pelvic movement asymmetry in horses with induced lameness.

    PubMed

    Rhodin, M; Pfau, T; Roepstorff, L; Egenvall, A

    2013-12-01

    Lungeing is an important part of lameness examinations, since the circular path enforced during lungeing is thought to accentuate low grade lameness. However, during lungeing the movement of sound horses becomes naturally asymmetric, which may mimic lameness. Also, compensatory movements in the opposite half of the body may mimic lameness. The aim of this study was to objectively study the presence of circle-dependent and compensatory movement asymmetries in horses with induced lameness. Ten horses were trotted in a straight line and lunged in both directions on a hard surface. Lameness was induced (reversible hoof pressure) in each limb, one at a time, in random order. Vertical head and pelvic movements were measured with body-mounted, uni-axial accelerometers. Differences between maximum and minimum height observed during/after left and right stance phases for the head (HDmax, HDmin) and pelvis (PDmax, PDmin) were measured. Mixed models were constructed to study the effect of lungeing direction and induction, and to quantify secondary compensatory asymmetry mechanisms in the forelimbs and hind limbs. Head and pelvic movement symmetries were affected by lungeing. Minimum pelvic height difference (PDmin) changed markedly, increasing significantly during lungeing, giving the impression of inner hind limb lameness. Primary hind limb lameness induced compensatory head movement, which mimicked an ipsilateral forelimb lameness of almost equal magnitude to the primary hind limb lameness. This could contribute to difficulty in correctly detecting hind limb lameness. Induced forelimb lameness caused both a compensatory contralateral (change in PDmax) and an ipsilateral (change in PDmin) hind limb asymmetry, potentially mimicking hind limb lameness, but of smaller magnitude. Both circle-dependent and compensatory movement mechanisms must be taken into account when evaluating lameness. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Compensatory Muscle Activation During Unstable Overhead Squat Using a Water-filled Training Tube.

    PubMed

    Glass, Stephen C; Albert, Robert W

    2018-05-01

    Glass, SC, and Albert, RW. Compensatory muscle activation during unstable overhead squat using a water-filled training tube. J Strength Cond Res 32(5): 1230-1237, 2018-The purpose of this study was to assess compensatory muscle activation of core and support muscle during an overhead squat using a water-filled training tube. Eleven experienced weightlifting (age = 20.10 ± 0.99, mass 89.17 ± 6.88 kg) men completed 3, 30-second trials of an overhead squat using an 11.4 kg tube that was partially filled with water. A central valve allowed 3 conditions of water movement: 50% open, 100% open, and a stable(S), closed valve condition. Subjects completed 8-10 repetitions within each condition. Electromyographic (EMG) electrodes were placed over the belly of the vastus lateralis, deltoid, rectus abdominus, and paraspinal muscles and recorded during concentric and eccentric (ECC) phases. Integrated EMG were computed and converted to percent maximal voluntary contraction (%MVC). Compensatory activation was assessed using the natural log of the coefficient of variation of %MVC across repetitions. A 1-way repeated-measures analysis of variance across (phase, condition) was used. Significant compensatory muscle activation was seen in the deltoid muscle during ECC (100% open = 3.60 ± 0.50 > stable LogCV = 3.06 ± 0.45). In addition, paraspinal muscle activity was also more variable during the ECC phase (50% open LogCv = 3.28 ± 0.26 > stable = 2.77 ± 0.67). We conclude that the water-filled training tube induces compensatory muscle activation in the deltoid and paraspinal muscles during the ECC phase of the overhead squat.

  9. Preexisting compensatory amino acids compromise fitness costs of a HIV-1 T cell escape mutation

    DOE PAGES

    Liu, Donglai; Zuo, Tao; Hora, Bhavna; ...

    2014-01-01

    Background: Fitness costs and slower disease progression are associated with a cytolytic T lymphocyte (CTL) escape mutation T242N in Gag in HIV-1-infected individuals carrying HLA-B*57/5801 alleles. However, the impact of different context in diverse HIV-1 strains on the fitness costs due to the T242N mutation has not been well characterized. To better understand the extent of fitness costs of the T242N mutation and the repair of fitness loss through compensatory amino acids, we investigated its fitness impact in different transmitted/founder (T/F) viruses. Results: The T242N mutation resulted in various levels of fitness loss in four different T/F viruses. However, themore » fitness costs were significantly compromised by preexisting compensatory amino acids in (Isoleucine at position 247) or outside (glutamine at position 219) the CTL epitope. Moreover, the transmitted T242N escape mutant in subject CH131 was as fit as the revertant N242T mutant and the elimination of the compensatory amino acid I247 in the T/F viral genome resulted in significant fitness cost, suggesting the fitness loss caused by the T242N mutation had been fully repaired in the donor at transmission. Analysis of the global circulating HIV-1 sequences in the Los Alamos HIV Sequence Database showed a high prevalence of compensatory amino acids for the T242N mutation and other T cell escape mutations. Conclusions: Our results show that the preexisting compensatory amino acids in the majority of circulating HIV-1 strains could significantly compromise the fitness loss due to CTL escape mutations and thus increase challenges for T cell based vaccines.« less

  10. Intraspecific priority effects modify compensatory responses to changes in hatching phenology in an amphibian.

    PubMed

    Murillo-Rincón, Andrea P; Kolter, Nora A; Laurila, Anssi; Orizaola, Germán

    2017-01-01

    In seasonal environments, modifications in the phenology of life-history events can alter the strength of time constraints experienced by organisms. Offspring can compensate for a change in timing of hatching by modifying their growth and development trajectories. However, intra- and interspecific interactions may affect these compensatory responses, in particular if differences in phenology between cohorts lead to significant priority effects (i.e. the competitive advantage that early-hatching individuals have over late-hatching ones). Here, we conducted a factorial experiment to determine whether intraspecific priority effects can alter compensatory phenotypic responses to hatching delay in a synchronic breeder by rearing moor frog (Rana arvalis) tadpoles in different combinations of phenological delay and food abundance. Tadpoles compensated for the hatching delay by speeding up their development, but only when reared in groups of individuals with identical hatching phenology. In mixed phenology groups, strong competitive effects by non-delayed tadpoles prevented the compensatory responses and delayed larvae metamorphosed later than in single phenology treatments. Non-delayed individuals gained advantage from developing with delayed larvae by increasing their developmental and growth rates as compared to single phenology groups. Food shortage prolonged larval period and reduced mass at metamorphosis in all treatments, but it did not prevent compensatory developmental responses in larvae reared in single phenology groups. This study demonstrates that strong intraspecific priority effects can constrain the compensatory growth and developmental responses to phenological change, and that priority effects can be an important factor explaining the maintenance of synchronic life histories (i.e. explosive breeding) in seasonal environments. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

  11. The evolution of dorsal-ventral patterning mechanisms in insects.

    PubMed

    Lynch, Jeremy A; Roth, Siegfried

    2011-01-15

    The gene regulatory network (GRN) underpinning dorsal-ventral (DV) patterning of the Drosophila embryo is among the most thoroughly understood GRNs, making it an ideal system for comparative studies seeking to understand the evolution of development. With the emergence of widely applicable techniques for testing gene function, species with sequenced genomes, and multiple tractable species with diverse developmental modes, a phylogenetically broad and molecularly deep understanding of the evolution of DV axis formation in insects is feasible. Here, we review recent progress made in this field, compare our emerging molecular understanding to classical embryological experiments, and suggest future directions of inquiry.

  12. Evolutionary molecular medicine.

    PubMed

    Nesse, Randolph M; Ganten, Detlev; Gregory, T Ryan; Omenn, Gilbert S

    2012-05-01

    Evolution has long provided a foundation for population genetics, but some major advances in evolutionary biology from the twentieth century that provide foundations for evolutionary medicine are only now being applied in molecular medicine. They include the need for both proximate and evolutionary explanations, kin selection, evolutionary models for cooperation, competition between alleles, co-evolution, and new strategies for tracing phylogenies and identifying signals of selection. Recent advances in genomics are transforming evolutionary biology in ways that create even more opportunities for progress at its interfaces with genetics, medicine, and public health. This article reviews 15 evolutionary principles and their applications in molecular medicine in hopes that readers will use them and related principles to speed the development of evolutionary molecular medicine.

  13. Size and habit evolution of PETN crystals - a lattice Monte Carlo study

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zepeda-Ruiz, L A; Maiti, A; Gee, R

    2006-02-28

    Starting from an accurate inter-atomic potential we develop a simple scheme of generating an ''on-lattice'' molecular potential of short range, which is then incorporated into a lattice Monte Carlo code for simulating size and shape evolution of nanocrystallites. As a specific example, we test such a procedure on the morphological evolution of a molecular crystal of interest to us, e.g., Pentaerythritol Tetranitrate, or PETN, and obtain realistic facetted structures in excellent agreement with experimental morphologies. We investigate several interesting effects including, the evolution of the initial shape of a ''seed'' to an equilibrium configuration, and the variation of growth morphologymore » as a function of the rate of particle addition relative to diffusion.« less

  14. Evolution: Understanding Life on Earth.

    ERIC Educational Resources Information Center

    Dybas, Cheryl Lyn

    2002-01-01

    Reports on presentations representing evolution at the 53rd annual meeting of the American Institute of Biological Sciences (AIBS) which was held March 22-24, 2002. Explains evolutionary patterns, phylogenetic pageantry, molecular clocks, speciation and biogeography, speciation and macroevolution, and human-induced evolution of drugs-resistant…

  15. Serial hepatic gene expression profiling in Angus steers during feed restriction and realimentation

    USDA-ARS?s Scientific Manuscript database

    Growing ruminants maintained under dietary restriction for extended periods will exhibit compensatory growth when reverted to ad libitum feeding. This period of compensatory growth is associated with increased feed efficiency, lower basal energy requirements, and changes in circulating concentration...

  16. Report: Enhanced Controls Needed to Prevent Further Abuse of Religious Compensatory Time

    EPA Pesticide Factsheets

    Report #16-P-0333, September 27, 2016. Inadequate controls for Religious Compensatory Time resulted in payouts to employees of $73,514, and may result in additional payouts of up to $81,927. For more information, please click on the link above.

  17. Compensatory growth in crossbred Aberdeen Angus and Belgian Blue steers: Effects on the colour, shear force and sensory characteristics of longissimus muscle.

    PubMed

    Keady, S M; Waters, S M; Hamill, R M; Dunne, P G; Keane, M G; Richardson, R I; Kenny, D A; Moloney, A P

    2017-03-01

    The effect of feed restriction (99days) followed by compensatory growth during a 200day re-alimentation period on the colour and sensory characteristics of meat from Aberdeen Angus×Holstein-Friesian (AN) and Belgian Blue×Holstein-Friesian (BB) steers was examined. Compensatory growth had no effect on muscle pH and temperature decline, chemical composition, drip loss, fat colour, or juiciness, but increased (P=0.009) Warner-Bratzler shear force and decreased tenderness (P=0.08) and overall liking (P=0.09). Compared to meat from BB steers, meat from AN steers had a higher intramuscular fat concentration and was rated similarly for tenderness, but higher for many of the flavour characteristics examined. While adjustment for intramuscular fat concentration removed some of these differences, genotype-specific flavour differences remained. It is concluded that genotype had greater effects on meat quality than the compensatory growth feeding regime imposed in this study. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Normalisation of brain connectivity through compensatory behaviour, despite congenital hand absence.

    PubMed

    Hahamy, Avital; Sotiropoulos, Stamatios N; Henderson Slater, David; Malach, Rafael; Johansen-Berg, Heidi; Makin, Tamar R

    2015-01-06

    Previously we showed, using task-evoked fMRI, that compensatory intact hand usage after amputation facilitates remapping of limb representations in the cortical territory of the missing hand (Makin et al., 2013a). Here we show that compensatory arm usage in individuals born without a hand (one-handers) reflects functional connectivity of spontaneous brain activity in the cortical hand region. Compared with two-handed controls, one-handers showed reduced symmetry of hand region inter-hemispheric resting-state functional connectivity and corticospinal white matter microstructure. Nevertheless, those one-handers who more frequently use their residual (handless) arm for typically bimanual daily tasks also showed more symmetrical functional connectivity of the hand region, demonstrating that adaptive behaviour drives long-range brain organisation. We therefore suggest that compensatory arm usage maintains symmetrical sensorimotor functional connectivity in one-handers. Since variability in spontaneous functional connectivity in our study reflects ecological behaviour, we propose that inter-hemispheric symmetry, typically observed in resting sensorimotor networks, depends on coordinated motor behaviour in daily life.

  19. Language Learning Variability within the Dorsal and Ventral Streams as a Cue for Compensatory Mechanisms in Aphasia Recovery

    PubMed Central

    López-Barroso, Diana; de Diego-Balaguer, Ruth

    2017-01-01

    Dorsal and ventral pathways connecting perisylvian language areas have been shown to be functionally and anatomically segregated. Whereas the dorsal pathway integrates the sensory-motor information required for verbal repetition, the ventral pathway has classically been associated with semantic processes. The great individual differences characterizing language learning through life partly correlate with brain structure and function within these dorsal and ventral language networks. Variability and plasticity within these networks also underlie inter-individual differences in the recovery of linguistic abilities in aphasia. Despite the division of labor of the dorsal and ventral streams, studies in healthy individuals have shown how the interaction of them and the redundancy in the areas they connect allow for compensatory strategies in functions that are usually segregated. In this mini-review we highlight the need to examine compensatory mechanisms between streams in healthy individuals as a helpful guide to choosing the most appropriate rehabilitation strategies, using spared functions and targeting preserved compensatory networks for brain plasticity. PMID:29021751

  20. [Orthotic management for patients with osteogenesis imperfecta].

    PubMed

    Alguacil Diego, I M; Molina Rueda, F; Gómez Conches, M

    2011-02-01

    Osteogenesis imperfecta (OI) is a disease caused by a genetic defect in the qualitative and quantitative synthesis of type I collagen. There is a wide variation in its clinical signs, characterized by bone fragility, resulting in a bone vulnerable to external and internal forces, determining the occurrence of frequent fractures with minimal or no trauma. The therapeutic objective is directed to improve the functional capacity of the child or adult concerned, adopting those compensatory strategies to optimise their independence. In this sense, the use of different orthoses and assistive technology are important for achieving these objectives. We reviewed the main contributions to this orthotic disease and the evolution of the different devices used in different databases over the last 25 years. Copyright © 2010 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  1. Applicability of the Compensatory Encoding Model in Foreign Language Reading: An Investigation with Chinese College English Language Learners

    PubMed Central

    Han, Feifei

    2017-01-01

    While some first language (L1) reading models suggest that inefficient word recognition and small working memory tend to inhibit higher-level comprehension processes; the Compensatory Encoding Model maintains that slow word recognition and small working memory do not normally hinder reading comprehension, as readers are able to operate metacognitive strategies to compensate for inefficient word recognition and working memory limitation as long as readers process a reading task without time constraint. Although empirical evidence is accumulated for support of the Compensatory Encoding Model in L1 reading, there is lack of research for testing of the Compensatory Encoding Model in foreign language (FL) reading. This research empirically tested the Compensatory Encoding Model in English reading among Chinese college English language learners (ELLs). Two studies were conducted. Study one focused on testing whether reading condition varying time affects the relationship between word recognition, working memory, and reading comprehension. Students were tested on a computerized English word recognition test, a computerized Operation Span task, and reading comprehension in time constraint and non-time constraint reading. The correlation and regression analyses showed that the strength of association was much stronger between word recognition, working memory, and reading comprehension in time constraint than that in non-time constraint reading condition. Study two examined whether FL readers were able to operate metacognitive reading strategies as a compensatory way of reading comprehension for inefficient word recognition and working memory limitation in non-time constraint reading. The participants were tested on the same computerized English word recognition test and Operation Span test. They were required to think aloud while reading and to complete the comprehension questions. The think-aloud protocols were coded for concurrent use of reading strategies, classified into language-oriented strategies, content-oriented strategies, re-reading, pausing, and meta-comment. The correlation analyses showed that while word recognition and working memory were only significantly related to frequency of language-oriented strategies, re-reading, and pausing, but not with reading comprehension. Jointly viewed, the results of the two studies, complimenting each other, supported the applicability of the Compensatory Encoding Model in FL reading with Chinese college ELLs. PMID:28522984

  2. Applicability of the Compensatory Encoding Model in Foreign Language Reading: An Investigation with Chinese College English Language Learners.

    PubMed

    Han, Feifei

    2017-01-01

    While some first language (L1) reading models suggest that inefficient word recognition and small working memory tend to inhibit higher-level comprehension processes; the Compensatory Encoding Model maintains that slow word recognition and small working memory do not normally hinder reading comprehension, as readers are able to operate metacognitive strategies to compensate for inefficient word recognition and working memory limitation as long as readers process a reading task without time constraint. Although empirical evidence is accumulated for support of the Compensatory Encoding Model in L1 reading, there is lack of research for testing of the Compensatory Encoding Model in foreign language (FL) reading. This research empirically tested the Compensatory Encoding Model in English reading among Chinese college English language learners (ELLs). Two studies were conducted. Study one focused on testing whether reading condition varying time affects the relationship between word recognition, working memory, and reading comprehension. Students were tested on a computerized English word recognition test, a computerized Operation Span task, and reading comprehension in time constraint and non-time constraint reading. The correlation and regression analyses showed that the strength of association was much stronger between word recognition, working memory, and reading comprehension in time constraint than that in non-time constraint reading condition. Study two examined whether FL readers were able to operate metacognitive reading strategies as a compensatory way of reading comprehension for inefficient word recognition and working memory limitation in non-time constraint reading. The participants were tested on the same computerized English word recognition test and Operation Span test. They were required to think aloud while reading and to complete the comprehension questions. The think-aloud protocols were coded for concurrent use of reading strategies, classified into language-oriented strategies, content-oriented strategies, re-reading, pausing, and meta-comment. The correlation analyses showed that while word recognition and working memory were only significantly related to frequency of language-oriented strategies, re-reading, and pausing, but not with reading comprehension. Jointly viewed, the results of the two studies, complimenting each other, supported the applicability of the Compensatory Encoding Model in FL reading with Chinese college ELLs.

  3. Phylogenomic Insights into Animal Evolution.

    PubMed

    Telford, Maximilian J; Budd, Graham E; Philippe, Hervé

    2015-10-05

    Animals make up only a small fraction of the eukaryotic tree of life, yet, from our vantage point as members of the animal kingdom, the evolution of the bewildering diversity of animal forms is endlessly fascinating. In the century following the publication of Darwin's Origin of Species, hypotheses regarding the evolution of the major branches of the animal kingdom - their relationships to each other and the evolution of their body plans - was based on a consideration of the morphological and developmental characteristics of the different animal groups. This morphology-based approach had many successes but important aspects of the evolutionary tree remained disputed. In the past three decades, molecular data, most obviously primary sequences of DNA and proteins, have provided an estimate of animal phylogeny largely independent of the morphological evolution we would ultimately like to understand. The molecular tree that has evolved over the past three decades has drastically altered our view of animal phylogeny and many aspects of the tree are no longer contentious. The focus of molecular studies on relationships between animal groups means, however, that the discipline has become somewhat divorced from the underlying biology and from the morphological characteristics whose evolution we aim to understand. Here, we consider what we currently know of animal phylogeny; what aspects we are still uncertain about and what our improved understanding of animal phylogeny can tell us about the evolution of the great diversity of animal life. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Recurrent Innovation at Genes Required for Telomere Integrity in Drosophila.

    PubMed

    Lee, Yuh Chwen G; Leek, Courtney; Levine, Mia T

    2017-02-01

    Telomeres are nucleoprotein complexes at the ends of linear chromosomes. These specialized structures ensure genome integrity and faithful chromosome inheritance. Recurrent addition of repetitive, telomere-specific DNA elements to chromosome ends combats end-attrition, while specialized telomere-associated proteins protect naked, double-stranded chromosome ends from promiscuous repair into end-to-end fusions. Although telomere length homeostasis and end-protection are ubiquitous across eukaryotes, there is sporadic but building evidence that the molecular machinery supporting these essential processes evolves rapidly. Nevertheless, no global analysis of the evolutionary forces that shape these fast-evolving proteins has been performed on any eukaryote. The abundant population and comparative genomic resources of Drosophila melanogaster and its close relatives offer us a unique opportunity to fill this gap. Here we leverage population genetics, molecular evolution, and phylogenomics to define the scope and evolutionary mechanisms driving fast evolution of genes required for telomere integrity. We uncover evidence of pervasive positive selection across multiple evolutionary timescales. We also document prolific expansion, turnover, and expression evolution in gene families founded by telomeric proteins. Motivated by the mutant phenotypes and molecular roles of these fast-evolving genes, we put forward four alternative, but not mutually exclusive, models of intra-genomic conflict that may play out at very termini of eukaryotic chromosomes. Our findings set the stage for investigating both the genetic causes and functional consequences of telomere protein evolution in Drosophila and beyond. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  5. State Compensatory Education Annual Report, 1982-83.

    ERIC Educational Resources Information Center

    Georgia State Dept. of Education, Atlanta. Office of Instructional Services.

    This document compiles compensatory education program data submitted to the Georgia State Department by local school systems in their 1982-83 annual reports. The first section describes state administration of grant funds (i.e., appropriations bills, procedures for allocating funds, program plans, and program monitoring). Specifically mentioned…

  6. COMPENSATORY EDUCATION PROGRAM. NEWSLETTER.

    ERIC Educational Resources Information Center

    Fresno City Unified School District, CA.

    TWO NEWSLETTERS FROM THE COMPENSATORY EDUCATION PROGRAM IN FRESNO INCLUDED PLANS FOR THE PLANNING GRANT PROGRAM, THE BASIC PROGRAM, AND THE INTENSIVE PROGRAM. THE BASIC PROGRAM SHOULD REDUCE PUPIL-TEACHER RATIO, PROVIDE PRESCHOOL PROJECTS THROUGH THE USE OF EITHER SCHOOL FACILITIES OR PRIVATE FACILITIES, PROVIDE REMEDIAL AND CORRECTIVE PROGRAMS IN…

  7. Effect of compensatory growth on Palmer amaranth response to glyphosate.

    USDA-ARS?s Scientific Manuscript database

    Incomplete weed control can occur after herbicide applications. Death of one or many shoot meristems could remove apical dominance, leading to compensatory growth from once dormant lateral buds. Palmer amaranth (PA) dieback and regrowth in response to POST herbicides has been observed. The objective...

  8. 49 CFR 91.9 - Distribution of compensatory funds.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Distribution of compensatory funds. 91.9 Section 91.9 Transportation Office of the Secretary of Transportation INTERNATIONAL AIR TRANSPORTATION FAIR... year, each U.S. flag air carrier which has been subjected to excessive or otherwise discriminatory...

  9. Comparative Analysis of Proteomes and Functionomes Provides Insights into Origins of Cellular Diversification

    PubMed Central

    Caetano-Anollés, Gustavo

    2013-01-01

    Reconstructing the evolutionary history of modern species is a difficult problem complicated by the conceptual and technical limitations of phylogenetic tree building methods. Here, we propose a comparative proteomic and functionomic inferential framework for genome evolution that allows resolving the tripartite division of cells and sketching their history. Evolutionary inferences were derived from the spread of conserved molecular features, such as molecular structures and functions, in the proteomes and functionomes of contemporary organisms. Patterns of use and reuse of these traits yielded significant insights into the origins of cellular diversification. Results uncovered an unprecedented strong evolutionary association between Bacteria and Eukarya while revealing marked evolutionary reductive tendencies in the archaeal genomic repertoires. The effects of nonvertical evolutionary processes (e.g., HGT, convergent evolution) were found to be limited while reductive evolution and molecular innovation appeared to be prevalent during the evolution of cells. Our study revealed a strong vertical trace in the history of proteins and associated molecular functions, which was reliably recovered using the comparative genomics approach. The trace supported the existence of a stem line of descent and the very early appearance of Archaea as a diversified superkingdom, but failed to uncover a hidden canonical pattern in which Bacteria was the first superkingdom to deploy superkingdom-specific structures and functions. PMID:24492748

  10. A new model for biological effects of radiation and the driven force of molecular evolution

    NASA Astrophysics Data System (ADS)

    Wada, Takahiro; Manabe, Yuichiro; Nakajima, Hiroo; Tsunoyama, Yuichi; Bando, Masako

    We proposed a new mathematical model to estimate biological effects of radiation, which we call Whack-A-Mole (WAM) model. A special feature of WAM model is that it involves the dose rate of radiation as a key ingredient. We succeeded to reproduce the experimental data of various species concerning the radiation induced mutation frequencies. From the analysis of the mega-mouse experiments, we obtained the mutation rate per base-pair per year for mice which is consistent with the so-called molecular clock in evolution genetics, 10-9 mutation/base-pair/year. Another important quantity is the equivalent dose rate for the whole spontaneous mutation, deff. The value of deff for mice is 1.1*10-3 Gy/hour which is much larger than the dose rate of natural radiation (10- (6 - 7) Gy/hour) by several orders of magnitude. We also analyzed Drosophila data and obtained essentially the same numbers. This clearly indicates that the natural radiation is not the dominant driving force of the molecular evolution, but we should look for other factors, such as miscopy of DNA in duplication process. We believe this is the first quantitative proof of the small contribution of the natural radiation in the molecular evolution.

  11. Evolution of heteromorphic sex chromosomes in the order Aulopiformes.

    PubMed

    Ota, K; Kobayashi, T; Ueno, K; Gojobori, T

    2000-12-23

    The fish order Aulopiformes contains both synchronously hermaphroditic and gonochoristic species. From the cytogenetic viewpoint, few reports show that gonochoristic Aulopiformes have heteromorphic sex chromosomes. Because fish in this order give us a unique opportunity to elucidate the evolution of sex chromosomes, it is important to examine a phylogenetic relationship in Aulopiformes by both molecular evolutionary and cytogenetic methods. Thus, we conducted molecular phylogenetic and cytogenetic studies of six Aulopiform species. Our results suggested that hermaphroditic species were evolutionarily derived from gonochoristic species. It follows that the hermaphroditic species might have lost the heteromorphic sex chromosomes during evolution. Here, we suggest a possibility that heteromorphic sex chromosomes can disappear from the genome, even if they have appeared once in evolution. Taking into account Ohno's hypothesis that heteromorphic sex chromosomes might have emerged from autosomes, we propose the hypothesis that heteromorphic sex chromosomes may have undergone repeated events of appearance and disappearance during the course of fish evolution.

  12. Precision pharmacology for Alzheimer's disease.

    PubMed

    Hampel, Harald; Vergallo, Andrea; Aguilar, Lisi Flores; Benda, Norbert; Broich, Karl; Cuello, A Claudio; Cummings, Jeffrey; Dubois, Bruno; Federoff, Howard J; Fiandaca, Massimo; Genthon, Remy; Haberkamp, Marion; Karran, Eric; Mapstone, Mark; Perry, George; Schneider, Lon S; Welikovitch, Lindsay A; Woodcock, Janet; Baldacci, Filippo; Lista, Simone

    2018-04-01

    The complex multifactorial nature of polygenic Alzheimer's disease (AD) presents significant challenges for drug development. AD pathophysiology is progressing in a non-linear dynamic fashion across multiple systems levels - from molecules to organ systems - and through adaptation, to compensation, and decompensation to systems failure. Adaptation and compensation maintain homeostasis: a dynamic equilibrium resulting from the dynamic non-linear interaction between genome, epigenome, and environment. An individual vulnerability to stressors exists on the basis of individual triggers, drivers, and thresholds accounting for the initiation and failure of adaptive and compensatory responses. Consequently, the distinct pattern of AD pathophysiology in space and time must be investigated on the basis of the individual biological makeup. This requires the implementation of systems biology and neurophysiology to facilitate Precision Medicine (PM) and Precision Pharmacology (PP). The regulation of several processes at multiple levels of complexity from gene expression to cellular cycle to tissue repair and system-wide network activation has different time delays (temporal scale) according to the affected systems (spatial scale). The initial failure might originate and occur at every level potentially affecting the whole dynamic interrelated systems within an organism. Unraveling the spatial and temporal dynamics of non-linear pathophysiological mechanisms across the continuum of hierarchical self-organized systems levels and from systems homeostasis to systems failure is key to understand AD. Measuring and, possibly, controlling space- and time-scaled adaptive and compensatory responses occurring during AD will represent a crucial step to achieve the capacity to substantially modify the disease course and progression at the best suitable timepoints, thus counteracting disrupting critical pathophysiological inputs. This approach will provide the conceptual basis for effective disease-modifying pathway-based targeted therapies. PP is based on an exploratory and integrative strategy to complex diseases such as brain proteinopathies including AD, aimed at identifying simultaneous aberrant molecular pathways and predicting their temporal impact on the systems levels. The depiction of pathway-based molecular signatures of complex diseases contributes to the accurate and mechanistic stratification of distinct subcohorts of individuals at the earliest compensatory stage when treatment intervention may reverse, stop, or delay the disease. In addition, individualized drug selection may optimize treatment safety by decreasing risk and amplitude of side effects and adverse reactions. From a methodological point of view, comprehensive "omics"-based biomarkers will guide the exploration of spatio-temporal systems-wide morpho-functional shifts along the continuum of AD pathophysiology, from adaptation to irreversible failure. The Alzheimer Precision Medicine Initiative (APMI) and the APMI cohort program (APMI-CP) have commenced to facilitate a paradigm shift towards effective drug discovery and development in AD. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Developmental trajectories of compensatory exercise and fasting behavior across the middle school years.

    PubMed

    Davis, Heather A; Guller, Leila; Smith, Gregory T

    2016-12-01

    Compensatory exercise and fasting behavior, in the absence of binge eating and purging, appear to be important eating disorder behaviors that are associated with dysfunction, but little is known about these behaviors in youth. We studied the trajectories of their development in non-binge eating and non-purging girls during early adolescence. Using a longitudinal design, we assessed 564 girls six times over the three years of middle school (grades 6 through 8) and developed trajectories specifying different developmental patterns in relation to the behaviors. Prior to this period, when the girls were in 5th grade (elementary school), we assessed risk factors to predict girls' subsequent trajectory group membership. Compensatory exercise trajectory groups included a non-engagement group, a group that increased in the behavior, and a group that decreased in the behavior. There were two fasting trajectory groups, one consistently engaging in the behavior and the other consistently not. Elementary school levels of depression, eating expectancies, and thinness expectancies predicted subsequent trajectory group membership. Risk for compensatory exercise and fasting should be evaluated as early as in 5th grade. Targeted interventions should focus on girls in late elementary school or middle school, as this appears to be a critical developmental and maintenance period for compensatory exercise and fasting behavior. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Comparative analysis of the mechanical signals in lung development and compensatory growth.

    PubMed

    Hsia, Connie C W

    2017-03-01

    This review compares the manner in which physical stress imposed on the parenchyma, vasculature and thorax and the thoraco-pulmonary interactions, drive both developmental and compensatory lung growth. Re-initiation of anatomical lung growth in the mature lung is possible when the loss of functioning lung units renders the existing physiologic-structural reserves insufficient for maintaining adequate function and physical stress on the remaining units exceeds a critical threshold. The appropriate spatial and temporal mechanical interrelationships and the availability of intra-thoracic space, are crucial to growth initiation, follow-on remodeling and physiological outcome. While the endogenous potential for compensatory lung growth is retained and may be pharmacologically augmented, supra-optimal mechanical stimulation, unbalanced structural growth, or inadequate remodeling may limit functional gain. Finding ways to optimize the signal-response relationships and resolve structure-function discrepancies are major challenges that must be overcome before the innate compensatory ability could be fully realized. Partial pneumonectomy reproducibly removes a known fraction of functioning lung units and remains the most robust model for examining the adaptive mechanisms, structure-function consequences and plasticity of the remaining functioning lung units capable of regeneration. Fundamental mechanical stimulus-response relationships established in the pneumonectomy model directly inform the exploration of effective approaches to maximize compensatory growth and function in chronic destructive lung diseases, transplantation and bioengineered lungs.

  15. Comparative Analysis of the Mechanical Signals in Lung Development and Compensatory Growth

    PubMed Central

    Hsia, Connie C.W.

    2017-01-01

    This review compares the manner in which physical stress imposed on the parenchyma, vasculature and thorax, and the thoraco-pulmonary interactions, drive both developmental and compensatory lung growth. Re-initiation of anatomical lung growth in the mature lung is possible when the loss of functioning lung units renders the existing physiologic-structural reserves insufficient for maintaining adequate function and physical stress on the remaining units exceeds a critical threshold. The appropriate spatial and temporal mechanical interrelationships, and the availability of intra-thoracic space, are crucial to growth initiation, follow-on remodeling and physiological outcome. While the endogenous potential for compensatory lung growth is retained and may be pharmacologically augmented, supra-optimal mechanical stimulation, unbalanced structural growth, or inadequate remodeling, may limit functional gain. Finding ways to optimize the signal-response relationships and resolve structure-function discrepancies are major challenges that must be overcome before the innate compensatory ability could be fully realized. Partial pneumonectomy reproducibly removes a known fraction of functioning lung units and remains the most robust model for examining the adaptive mechanisms, structure-function consequences, and plasticity of the remaining functioning lung units capable of regeneration. Fundamental mechanical stimulus-response relationships established in the pneumonectomy model directly inform the exploration of effective approaches to maximize compensatory growth and function in chronic destructive lung diseases, transplantation and bioengineered lungs. PMID:28084523

  16. Chewing and spitting out food as a compensatory behavior in patients with eating disorders.

    PubMed

    Song, Youn Joo; Lee, Jung-Hyun; Jung, Young-Chul

    2015-10-01

    Recent studies suggest that chewing and spitting out food may be associated with severe eating-related pathology. The purpose of this study was to investigate the relationship between chewing and spitting, and other symptoms of eating disorders. We hypothesized that patients who chew and spit as a compensatory behavior have more severe eating-related pathology than patients who have never engaged in chewing and spitting behavior. We divided 359 patients with eating disorders into two groups according to whether they engaged in chewing and spitting as a compensatory behavior to lose weight or not. After comparing eating-related pathology between the two groups, we examined factors associated with pathologic eating behaviors using logistic regression analysis. Among our 359 participants, 24.5% reported having engaged in chewing and spitting as a compensatory behavior. The chewing and spitting (CHSP+) group showed more severe eating disorder symptoms and suicidal behaviors. This group also had significantly higher scores on subscales that measured drive for thinness, bulimia, and impulse regulation on the EDI-2, Food Craving Questionnaire, Body Shape Questionnaire, Beck Depression Inventory, Beck Anxiety Inventory, and Maudsley Obsessive Compulsive Inventory. Chewing and spitting is a common compensatory behavior among patients with eating disorders and is associated with more-pathologic eating behaviors and higher scores on psychometric tests. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Flexible compensation of uniparental care: female poison frogs take over when males disappear

    PubMed Central

    Pašukonis, Andrius; Fitch, W. Tecumseh; Huber, Ludwig; Hödl, Walter; Ringler, Max

    2015-01-01

    Parental care systems are shaped by costs and benefits to each sex of investing into current versus future progeny. Flexible compensatory parental care is mainly known in biparental species, particularly where parental desertion or reduction of care by 1 parent is common. The other parent can then compensate this loss by either switching parental roles and/or by increasing its own parental effort. In uniparental species, desertion of the caregiver usually leads to total brood loss. In the poison frog, Allobates femoralis, obligatory tadpole transport (TT) is generally performed by males, whereas females abandon their clutches after oviposition. Nevertheless, in a natural population we previously observed 7.8% of TT performed by females, which we could link to the absence of the respective fathers. In the following experiment, under laboratory conditions, all tested A. femoralis females flexibly took over parental duties, but only when their mates were removed. Our findings provide clear evidence for compensatory flexibility in a species with unisexual parental care. Contrary to the view of amphibian parental care as being stereotypical and fixed, these results demonstrate behavioral flexibility as an adaptive response to environmental and social uncertainty. Behavioral flexibility might actually represent a crucial step in the evolutionary transition from uniparental to biparental care in poison frogs. We suspect that across animal species flexible parental roles are much more common than previously thought and suggest the idea of a 3-dimensional continuum regarding flexibility, parental involvement, and timing, when thinking about the evolution of parental care. PMID:26167099

  18. A scaling law of radial gas distribution in disk galaxies

    NASA Technical Reports Server (NTRS)

    Wang, Zhong

    1990-01-01

    Based on the idea that local conditions within a galactic disk largely determine the region's evolution time scale, researchers built a theoretical model to take into account molecular cloud and star formations in the disk evolution process. Despite some variations that may be caused by spiral arms and central bulge masses, they found that many late-type galaxies show consistency with the model in their radial atomic and molecular gas profiles. In particular, researchers propose that a scaling law be used to generalize the gas distribution characteristics. This scaling law may be useful in helping to understand the observed gas contents in many galaxies. Their model assumes an exponential mass distribution with disk radius. Most of the mass are in atomic gas state at the beginning of the evolution. Molecular clouds form through a modified Schmidt Law which takes into account gravitational instabilities in a possible three-phase structure of diffuse interstellar medium (McKee and Ostriker, 1977; Balbus and Cowie, 1985); whereas star formation proceeds presumably unaffected by the environmental conditions outside of molecular clouds (Young, 1987). In such a model both atomic and molecular gas profiles in a typical galactic disk (as a result of the evolution) can be fitted simultaneously by adjusting the efficiency constants. Galaxies of different sizes and masses, on the other hand, can be compared with the model by simply scaling their characteristic length scales and shifting their radial ranges to match the assumed disk total mass profile sigma tot(r).

  19. In Vivo-Selected Compensatory Mutations Restore the Fitness Cost of Mosaic penA Alleles That Confer Ceftriaxone Resistance in Neisseria gonorrhoeae.

    PubMed

    Vincent, Leah R; Kerr, Samuel R; Tan, Yang; Tomberg, Joshua; Raterman, Erica L; Dunning Hotopp, Julie C; Unemo, Magnus; Nicholas, Robert A; Jerse, Ann E

    2018-04-03

    Resistance to ceftriaxone in Neisseria gonorrhoeae is mainly conferred by mosaic penA alleles that encode penicillin-binding protein 2 (PBP2) variants with markedly lower rates of acylation by ceftriaxone. To assess the impact of these mosaic penA alleles on gonococcal fitness, we introduced the mosaic penA alleles from two ceftriaxone-resistant (Cro r ) clinical isolates (H041 and F89) into a Cro s strain (FA19) by allelic exchange and showed that the resultant Cro r mutants were significantly outcompeted by the Cro s parent strain in vitro and in a murine infection model. Four Cro r compensatory mutants of FA19 penA41 were isolated independently from mice that outcompeted the parent strain both in vitro and in vivo One of these compensatory mutants (LV41C) displayed a unique growth profile, with rapid log growth followed by a sharp plateau/gradual decline at stationary phase. Genome sequencing of LV41C revealed a mutation (G348D) in the acnB gene encoding the bifunctional aconitate hydratase 2/2 methylisocitrate dehydratase. Introduction of the acnB G348D allele into FA19 penA41 conferred both a growth profile that phenocopied that of LV41C and a fitness advantage, although not as strongly as that exhibited by the original compensatory mutant, suggesting the existence of additional compensatory mutations. The mutant aconitase appears to be a functional knockout with lower activity and expression than wild-type aconitase. Transcriptome sequencing (RNA-seq) analysis of FA19 penA41 acnB G348D revealed a large set of upregulated genes involved in carbon and energy metabolism. We conclude that compensatory mutations can be selected in Cro r gonococcal strains that increase metabolism to ameliorate their fitness deficit. IMPORTANCE The emergence of ceftriaxone-resistant (Cro r ) Neisseria gonorrhoeae has led to the looming threat of untreatable gonorrhea. Whether Cro resistance is likely to spread can be predicted from studies that compare the relative fitnesses of susceptible and resistant strains that differ only in the penA gene that confers Cro resistance. We showed that mosaic penA alleles found in Cro r clinical isolates are outcompeted by the Cro s parent strain in vitro and in vivo but that compensatory mutations that allow ceftriaxone resistance to be maintained by increasing bacterial fitness are selected during mouse infection. One compensatory mutant that was studied in more detail had a mutation in acnB , which encodes the aconitase that functions in the tricarboxylic acid (TCA) cycle. This study illustrates that compensatory mutations can be selected during infection, which we hypothesize may allow the spread of Cro resistance in nature. This study also provides novel insights into gonococcal metabolism and physiology.

  20. 29 CFR 553.21 - Statutory provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... such work was any other work, the employee engaged in such work may accrue not more than 240 hours of... accrued 480 or 240 hours, as the case may be, of compensatory time off shall, for additional overtime... the employee receives such payment. (4) An employee who has accrued compensatory time off authorized...

  1. Organizational Agility Model and Simulation

    DTIC Science & Technology

    2011-06-01

    and response profile. Also, compensatory, anticipatory , adaptive, and learning behaviours (methods) are employed to modify stiffness and resistance...The hypothetical profile in Figure 1b shows some complexity changes for a major sporting event or...classical motion tracking problem using compensatory, anticipatory , adaptive, and learning behaviours. These behaviours modify the size, resistance, and

  2. Compensatory Education: An Analysis of National Versus State and Local Evaluations.

    ERIC Educational Resources Information Center

    Stickney, Benjamin D.

    Discrepancies between the pessimistic national evaluations and the more encouraging state and local evaluations of compensatory education programs are explored in this paper. A conventional explanation for the discrepancies, namely, that the averaging of test scores from a large national sample "cancels out" the results of successful…

  3. Compensatory Early Childhood Education for Educationally Disadvantaged Children in Germany and Beyond

    ERIC Educational Resources Information Center

    Schmidt, T.

    2016-01-01

    The article examines the relevance of compensatory education for educationally disadvantaged children of preschool age in Germany and beyond The article is a shortened, adapted and translated version of the paper Schmidt, T., & Smidt, W. (2014). "Kompensatorische Förderung benachteiligter Kinder--Entwicklungslinien, Forschungsbefunde und…

  4. 5 CFR 550.1002 - Compensatory time off for religious observances.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Compensatory time off for religious... personal religious beliefs require the abstention from work during certain periods of time may elect to... religious observances when the employee's personal religious beliefs require that the employee abstain from...

  5. 5 CFR 550.1002 - Compensatory time off for religious observances.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Compensatory time off for religious... personal religious beliefs require the abstention from work during certain periods of time may elect to... religious observances when the employee's personal religious beliefs require that the employee abstain from...

  6. 5 CFR 550.1002 - Compensatory time off for religious observances.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Compensatory time off for religious... personal religious beliefs require the abstention from work during certain periods of time may elect to... religious observances when the employee's personal religious beliefs require that the employee abstain from...

  7. 5 CFR 550.1002 - Compensatory time off for religious observances.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Compensatory time off for religious... personal religious beliefs require the abstention from work during certain periods of time may elect to... religious observances when the employee's personal religious beliefs require that the employee abstain from...

  8. 5 CFR 550.1002 - Compensatory time off for religious observances.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Compensatory time off for religious... personal religious beliefs require the abstention from work during certain periods of time may elect to... religious observances when the employee's personal religious beliefs require that the employee abstain from...

  9. 1979 Special Report on the NIE Compensatory Education Study.

    ERIC Educational Resources Information Center

    National Advisory Council on the Education of Disadvantaged Children, Washington, DC.

    This document examines the National Institute of Education's (NIE) Final Report on its study of compensatory education. Objectives of the NIE study and strategies used by NIE to accomplish these objectives are summarized. The five main chapters of the Final Report dealing respectively with demonstration studies, teacher training, the Instructional…

  10. Curriculum in Early Childhood Education.

    ERIC Educational Resources Information Center

    Bernard Van Leer Foundation, The Hague (Netherlands).

    At a seminar on Compensatory Early Childhood Education held in Jerusalem in the fall of 1972 the idea of compensatory education and its viability in cross cultural terms was examined in conjunction with a critical review of the whole notion of social and cultural disadvantage. Twenty-two participants from international governmental organizations…

  11. 5 CFR 550.1401 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) Compensatory Time Off for Travel § 550.1401 Purpose. This subpart contains OPM regulations implementing 5 U.S.C. 5550b, which establishes a separate type of compensatory time off. Subject to the conditions specified... for time in a travel status away from the employee's official duty station when the travel time is not...

  12. 5 CFR 550.1401 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) Compensatory Time Off for Travel § 550.1401 Purpose. This subpart contains OPM regulations implementing 5 U.S.C. 5550b, which establishes a separate type of compensatory time off. Subject to the conditions specified... for time in a travel status away from the employee's official duty station when the travel time is not...

  13. 5 CFR 550.1401 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) Compensatory Time Off for Travel § 550.1401 Purpose. This subpart contains OPM regulations implementing 5 U.S.C. 5550b, which establishes a separate type of compensatory time off. Subject to the conditions specified... for time in a travel status away from the employee's official duty station when the travel time is not...

  14. 5 CFR 550.1401 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) Compensatory Time Off for Travel § 550.1401 Purpose. This subpart contains OPM regulations implementing 5 U.S.C. 5550b, which establishes a separate type of compensatory time off. Subject to the conditions specified... for time in a travel status away from the employee's official duty station when the travel time is not...

  15. 5 CFR 550.1401 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Compensatory Time Off for Travel § 550.1401 Purpose. This subpart contains OPM regulations implementing 5 U.S.C. 5550b, which establishes a separate type of compensatory time off. Subject to the conditions specified... for time in a travel status away from the employee's official duty station when the travel time is not...

  16. 29 CFR 24.110 - Decision and orders of the Administrative Review Board.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ENERGY REORGANIZATION ACT OF 1974, AS AMENDED Litigation § 24.110 Decision and orders of the... issued under the Energy Reorganization Act, other than that portion of the order awarding compensatory... employment, and compensatory damages. In cases arising under the Safe Drinking Water Act or the Toxic...

  17. 29 CFR 24.110 - Decision and orders of the Administrative Review Board.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ENERGY REORGANIZATION ACT OF 1974, AS AMENDED Litigation § 24.110 Decision and orders of the... issued under the Energy Reorganization Act, other than that portion of the order awarding compensatory... employment, and compensatory damages. In cases arising under the Safe Drinking Water Act or the Toxic...

  18. 29 CFR 24.110 - Decision and orders of the Administrative Review Board.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ENERGY REORGANIZATION ACT OF 1974, AS AMENDED Litigation § 24.110 Decision and orders of the... issued under the Energy Reorganization Act, other than that portion of the order awarding compensatory... employment, and compensatory damages. In cases arising under the Safe Drinking Water Act or the Toxic...

  19. 29 CFR 24.110 - Decision and orders of the Administrative Review Board.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ENERGY REORGANIZATION ACT OF 1974, AS AMENDED Litigation § 24.110 Decision and orders of the... issued under the Energy Reorganization Act, other than that portion of the order awarding compensatory... employment, and compensatory damages. In cases arising under the Safe Drinking Water Act or the Toxic...

  20. An evaluation of North Carolina Department of Transportation wetland mitigation sites : selected case studies, phase 2 report.

    DOT National Transportation Integrated Search

    2012-03-01

    Phase 1 of this study evaluated 50 NCDOT wetland compensatory mitigation sites and 11 reference sites in 1999. The : Phase 2 component (this report) examines five of the compensatory mitigation sites to provide a more in-depth analysis. The : objecti...

  1. The Evaluation and Selection of Adequate Causal Models: A Compensatory Education Example.

    ERIC Educational Resources Information Center

    Tanaka, Jeffrey S.

    1982-01-01

    Implications of model evaluation (using traditional chi square goodness of fit statistics, incremental fit indices for covariance structure models, and latent variable coefficients of determination) on substantive conclusions are illustrated with an example examining the effects of participation in a compensatory education program on posttreatment…

  2. Patterns of Compensatory Behaviors and Disordered Eating in College Students

    ERIC Educational Resources Information Center

    Schaumberg, Katherine; Anderson, Lisa M.; Reilly, Erin; Anderson, Drew A.

    2014-01-01

    Objective: The current study investigated rates of endorsement of eating-related compensatory behaviors within a college sample. Participants: This sample included male and female students (N = 1,158). Methods: Participants completed the Eating Disorder Examination Questionnaire (EDE-Q). The study defined 3 groups of students: those who did not…

  3. Parent Involvement in Compensatory Education.

    ERIC Educational Resources Information Center

    Gordon, Ira J.

    This monograph considers the effects of the family on the intellectual and personal development of the child, and the effects of culture upon the family's way of life, and thus, on the child. In a survey of early compensatory education projects, university based programs, and school and community programs are described. Program organizational…

  4. Affective Variables Indicating Success for Compensatory Education Projects.

    ERIC Educational Resources Information Center

    Cavin, Alonzo; And Others

    This document is a study of the importance of affective variables and the implications of these variables in student success or failure. A 28 item questionnaire was administered to 30 college students enrolled in a compensatory education program. The questionnaire assessed attitudes toward professors, administrators, peers, toward relevance of…

  5. EFFECT OF LOW LEVEL CARBON MONOXIDE ON COMPENSATORY TRACKING AND EVENT MONITORING

    EPA Science Inventory

    Experiments by Putz et al. concerning the effect of carbon monoxide (CO) exposure on compensatory tracking and monitoring in healthy young men were replicated. Task and procedural variables were reproduced as closely as practical. Subjects were exposed to either room air or 100 p...

  6. District Survey I. Policy Research Corporation Analyses. Final Report.

    ERIC Educational Resources Information Center

    Policy Research Corp., Chicago, IL.

    This study, mandated by Congress in the Education Amendments of 1974, was designed to produce estimates which describe the goals of compensatory programs, program operating characteristics, and evaluation techniques in use in compensatory programs. For the purpose of the study, the population sample was defined as all operating public school…

  7. Research Plan: Compensatory Education Study.

    ERIC Educational Resources Information Center

    National Inst. of Education (DHEW), Washington, DC.

    This research plan is a direct response to the education Amendments of 1974 which instructs the National Institute of Education to design and conduct a compensatory education study. The research design, as outlined in this report, intends to examine programs and look for identifiable factors in funding, organization, and instructional methods…

  8. Sacramento City Unified School District Chapter 1/State Compensatory Education Handbook Series.

    ERIC Educational Resources Information Center

    Sacramento City Unified School District, CA.

    Four handbooks developed by the Consolidated Programs Department of the Sacramento City Unified School District (California) provide a means by which the multitude of federal, state, and district rules and regulations pertaining to compensatory education can be understood. The "Consolidated Programs Office Management Procedures" handbook…

  9. Resistance to pyridine-based inhibitor KF116 reveals an unexpected role of integrase in HIV-1 Gag-Pol polyprotein proteolytic processing.

    PubMed

    Hoyte, Ashley C; Jamin, Augusta V; Koneru, Pratibha C; Kobe, Matthew J; Larue, Ross C; Fuchs, James R; Engelman, Alan N; Kvaratskhelia, Mamuka

    2017-12-01

    The pyridine-based multimerization selective HIV-1 integrase (IN) inhibitors (MINIs) are a distinct subclass of allosteric IN inhibitors. MINIs potently inhibit HIV-1 replication during virion maturation by inducing hyper- or aberrant IN multimerization but are largely ineffective during the early steps of viral replication. Here, we investigated the mechanism for the evolution of a triple IN substitution (T124N/V165I/T174I) that emerges in cell culture with a representative MINI, KF116. We show that HIV-1 NL4-3(IN T124N/V165I/T174I) confers marked (>2000-fold) resistance to KF116. Two IN substitutions (T124N/T174I) directly weaken inhibitor binding at the dimer interface of the catalytic core domain but at the same time markedly impair HIV-1 replication capacity. Unexpectedly, T124N/T174I IN substitutions inhibited proteolytic processing of HIV-1 polyproteins Gag and Gag-Pol, resulting in immature virions. Strikingly, the addition of the third IN substitution (V165I) restored polyprotein processing, virus particle maturation, and significant levels of replication capacity. These results reveal an unanticipated role of IN for polyprotein proteolytic processing during virion morphogenesis. The complex evolutionary pathway for the emergence of resistant viruses, which includes the need for the compensatory V165I IN substitution, highlights a relatively high genetic barrier exerted by MINI KF116. Additionally, we have solved the X-ray structure of the drug-resistant catalytic core domain protein, which provides means for rational development of second-generation MINIs. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Genome-Wide DNA Methylation Profiling Reveals Epigenetic Adaptation of Stickleback to Marine and Freshwater Conditions.

    PubMed

    Artemov, Artem V; Mugue, Nikolai S; Rastorguev, Sergey M; Zhenilo, Svetlana; Mazur, Alexander M; Tsygankova, Svetlana V; Boulygina, Eugenia S; Kaplun, Daria; Nedoluzhko, Artem V; Medvedeva, Yulia A; Prokhortchouk, Egor B

    2017-09-01

    The three-spined stickleback (Gasterosteus aculeatus) represents a convenient model to study microevolution-adaptation to a freshwater environment. Although genetic adaptations to freshwater environments are well-studied, epigenetic adaptations have attracted little attention. In this work, we investigated the role of DNA methylation in the adaptation of the marine stickleback population to freshwater conditions. DNA methylation profiling was performed in marine and freshwater populations of sticklebacks, as well as in marine sticklebacks placed into a freshwater environment and freshwater sticklebacks placed into seawater. We showed that the DNA methylation profile after placing a marine stickleback into fresh water partially converged to that of a freshwater stickleback. For six genes including ATP4A ion pump and NELL1, believed to be involved in skeletal ossification, we demonstrated similar changes in DNA methylation in both evolutionary and short-term adaptation. This suggested that an immediate epigenetic response to freshwater conditions can be maintained in freshwater population. Interestingly, we observed enhanced epigenetic plasticity in freshwater sticklebacks that may serve as a compensatory regulatory mechanism for the lack of genetic variation in the freshwater population. For the first time, we demonstrated that genes encoding ion channels KCND3, CACNA1FB, and ATP4A were differentially methylated between the marine and the freshwater populations. Other genes encoding ion channels were previously reported to be under selection in freshwater populations. Nevertheless, the genes that harbor genetic and epigenetic changes were not the same, suggesting that epigenetic adaptation is a complementary mechanism to selection of genetic variants favorable for freshwater environment. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Molecular recognition of the environment and mechanisms of the origin of species in quantum-like modeling of evolution.

    PubMed

    Melkikh, Alexey V; Khrennikov, Andrei

    2017-11-01

    A review of the mechanisms of speciation is performed. The mechanisms of the evolution of species, taking into account the feedback of the state of the environment and mechanisms of the emergence of complexity, are considered. It is shown that these mechanisms, at the molecular level, cannot work steadily in terms of classical mechanics. Quantum mechanisms of changes in the genome, based on the long-range interaction potential between biologically important molecules, are proposed as one of possible explanation. Different variants of interactions of the organism and environment based on molecular recognition and leading to new species origins are considered. Experiments to verify the model are proposed. This bio-physical study is completed by the general operational model of based on quantum information theory. The latter is applied to model of epigenetic evolution. We briefly present the basics of the quantum-like approach to modeling of bio-informational processes. This approach is illustrated by the quantum-like model of epigenetic evolution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Molecular hyperdiversity and evolution in very large populations.

    PubMed

    Cutter, Asher D; Jovelin, Richard; Dey, Alivia

    2013-04-01

    The genomic density of sequence polymorphisms critically affects the sensitivity of inferences about ongoing sequence evolution, function and demographic history. Most animal and plant genomes have relatively low densities of polymorphisms, but some species are hyperdiverse with neutral nucleotide heterozygosity exceeding 5%. Eukaryotes with extremely large populations, mimicking bacterial and viral populations, present novel opportunities for studying molecular evolution in sexually reproducing taxa with complex development. In particular, hyperdiverse species can help answer controversial questions about the evolution of genome complexity, the limits of natural selection, modes of adaptation and subtleties of the mutation process. However, such systems have some inherent complications and here we identify topics in need of theoretical developments. Close relatives of the model organisms Caenorhabditis elegans and Drosophila melanogaster provide known examples of hyperdiverse eukaryotes, encouraging functional dissection of resulting molecular evolutionary patterns. We recommend how best to exploit hyperdiverse populations for analysis, for example, in quantifying the impact of noncrossover recombination in genomes and for determining the identity and micro-evolutionary selective pressures on noncoding regulatory elements. © 2013 Blackwell Publishing Ltd.

  13. The eyes have it: A Problem-Based Learning Exercise in Molecular Evolution.

    PubMed

    White, Harold B

    2007-05-01

    Molecular evolution provides an interesting context in which to use problem-based learning because it integrates a variety of topics in biology, biochemistry, and molecular biology. This three-stage problem for advanced students deals with the structure, multiple functions, and properties of lactate dehydrogenase isozymes, and the related evolutionary trade offs of gene sharing versus gene duplication among their corresponding genes. It has directive elements that require students to find and read classic articles, review thermodynamic principles, and apply their understanding to a mythical world wherein dinosaurs continued to evolve. The science fiction writing assignment that brings closure to the problem transformed the problem with respect to student interest and engagement. Copyright © 2007 International Union of Biochemistry and Molecular Biology, Inc.

  14. A Splash to Nano-Sized Inorganic Energy-Materials by the Low-Temperature Molecular Precursor Approach.

    PubMed

    Driess, Matthias; Panda, Chakadola; Menezes, Prashanth Wilfried

    2018-05-07

    The low-temperature synthesis of inorganic materials and their interfaces at the atomic and molecular level provides numerous opportunities for the design and improvement of inorganic materials in heterogeneous catalysis for sustainable chemical energy conversion or other energy-saving areas. Using suitable molecular precursors for functional inorganic nanomaterial synthesis allows for facile control over uniform particle size distribution, stoichiometry, and leads to desired chemical and physical properties. This minireview outlines some advantages of the molecular precursor approach in light of selected recent developments of molecule-to-nanomaterials synthesis for renewable energy applications, relevant for the oxygen evolution reaction (OER), hydrogen evolution reaction (HER) and overall water-splitting. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Metabolic rate does not calibrate the molecular clock

    PubMed Central

    Lanfear, Robert; Thomas, Jessica A.; Welch, John J.; Brey, Thomas; Bromham, Lindell

    2007-01-01

    Rates of molecular evolution vary widely among lineages, but the causes of this variation remain poorly understood. It has been suggested that mass-specific metabolic rate may be one of the key factors determining the rate of molecular evolution, and that it can be used to derive “corrected” molecular clocks. However, previous studies have been hampered by a paucity of mass-specific metabolic rate data and have been largely limited to vertebrate taxa. Using mass-specific metabolic rate measurements and DNA sequence data for >300 metazoan species for 12 different genes, we find no evidence that mass-specific metabolic rate drives substitution rates. The mechanistic basis of the metabolic rate hypothesis is discussed in light of these findings. PMID:17881572

  16. Evolution of an ancient protein function involved in organized multicellularity in animals.

    PubMed

    Anderson, Douglas P; Whitney, Dustin S; Hanson-Smith, Victor; Woznica, Arielle; Campodonico-Burnett, William; Volkman, Brian F; King, Nicole; Thornton, Joseph W; Prehoda, Kenneth E

    2016-01-07

    To form and maintain organized tissues, multicellular organisms orient their mitotic spindles relative to neighboring cells. A molecular complex scaffolded by the GK protein-interaction domain (GKPID) mediates spindle orientation in diverse animal taxa by linking microtubule motor proteins to a marker protein on the cell cortex localized by external cues. Here we illuminate how this complex evolved and commandeered control of spindle orientation from a more ancient mechanism. The complex was assembled through a series of molecular exploitation events, one of which - the evolution of GKPID's capacity to bind the cortical marker protein - can be recapitulated by reintroducing a single historical substitution into the reconstructed ancestral GKPID. This change revealed and repurposed an ancient molecular surface that previously had a radically different function. We show how the physical simplicity of this binding interface enabled the evolution of a new protein function now essential to the biological complexity of many animals.

  17. The QTN program and the alleles that matter for evolution: all that's gold does not glitter.

    PubMed

    Rockman, Matthew V

    2012-01-01

    The search for the alleles that matter, the quantitative trait nucleotides (QTNs) that underlie heritable variation within populations and divergence among them, is a popular pursuit. But what is the question to which QTNs are the answer? Although their pursuit is often invoked as a means of addressing the molecular basis of phenotypic evolution or of estimating the roles of evolutionary forces, the QTNs that are accessible to experimentalists, QTNs of relatively large effect, may be uninformative about these issues if large-effect variants are unrepresentative of the alleles that matter. Although 20th century evolutionary biology generally viewed large-effect variants as atypical, the field has recently undergone a quiet realignment toward a view of readily discoverable large-effect alleles as the primary molecular substrates for evolution. I argue that neither theory nor data justify this realignment. Models and experimental findings covering broad swaths of evolutionary phenomena suggest that evolution often acts via large numbers of small-effect polygenes, individually undetectable. Moreover, these small-effect variants are different in kind, at the molecular level, from the large-effect alleles accessible to experimentalists. Although discoverable QTNs address some fundamental evolutionary questions, they are essentially misleading about many others. © 2011 The Author(s). Evolution © 2011 The Society for the Study of Evolution.

  18. Compensatory mortality in mule deer populations. Technical progress report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    White, G.C.

    1986-03-15

    The hypothesis of compensatory mortality is critical to understanding population dynamics of wildlife species. This is vital regardless of whether populations are managed for recreational hunting or habitats are altered via energy development projects. The purpose of research summarized herein is to test for compensatory mortality during winter in the juvenile (fawn) portion of a mule deer population. In the fall of 1985, sixty fawns were radio collared on both the control and treatment sites of the Little Hills study area. Thirty-three adult females also were telemetered, bringing the total instrumented population to 167 at the onset of winter. 10more » refs., 1 fig., 6 tabs.« less

  19. Negative association between parental care and sibling cooperation in earwigs: a new perspective on the early evolution of family life?

    PubMed

    Kramer, J; Thesing, J; Meunier, J

    2015-07-01

    The evolution of family life requires net fitness benefits for offspring, which are commonly assumed to mainly derive from parental care. However, an additional source of benefits for offspring is often overlooked: cooperative interactions among juvenile siblings. In this study, we examined how sibling cooperation and parental care could jointly contribute to the early evolution of family life. Specifically, we tested whether the level of food transferred among siblings (sibling cooperation) in the European earwig Forficula auricularia (1) depends on the level of maternal food provisioning (parental care) and (2) is translated into offspring survival, as well as female investment into future reproduction. We show that higher levels of sibling food transfer were associated with lower levels of maternal food provisioning, possibly reflecting a compensatory relationship between sibling cooperation and maternal care. Furthermore, the level of sibling food transfer did not influence offspring survival, but was associated with negative effects on the production of the second and terminal clutch by the tending mothers. These findings indicate that sibling cooperation could mitigate the detrimental effects on offspring survival that result from being tended by low-quality mothers. More generally, they are in line with the hypothesis that sibling cooperation is an ancestral behaviour that can be retained to compensate for insufficient levels of parental investment. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  20. A Phylogenomic Census of Molecular Functions Identifies Modern Thermophilic Archaea as the Most Ancient Form of Cellular Life

    PubMed Central

    Kim, Kyung Mo; Caetano-Anollés, Gustavo

    2014-01-01

    The origins of diversified life remain mysterious despite considerable efforts devoted to untangling the roots of the universal tree of life. Here we reconstructed phylogenies that described the evolution of molecular functions and the evolution of species directly from a genomic census of gene ontology (GO) definitions. We sampled 249 free-living genomes spanning organisms in the three superkingdoms of life, Archaea, Bacteria, and Eukarya, and used the abundance of GO terms as molecular characters to produce rooted phylogenetic trees. Results revealed an early thermophilic origin of Archaea that was followed by genome reduction events in microbial superkingdoms. Eukaryal genomes displayed extraordinary functional diversity and were enriched with hundreds of novel molecular activities not detected in the akaryotic microbial cells. Remarkably, the majority of these novel functions appeared quite late in evolution, synchronized with the diversification of the eukaryal superkingdom. The distribution of GO terms in superkingdoms confirms that Archaea appears to be the simplest and most ancient form of cellular life, while Eukarya is the most diverse and recent. PMID:25249790

  1. The Evolutionary Dynamics of the Odorant Receptor Gene Family in Corbiculate Bees.

    PubMed

    Brand, Philipp; Ramírez, Santiago R

    2017-08-01

    Insects rely on chemical information to locate food, choose mates, and detect potential predators. It has been hypothesized that adaptive changes in the olfactory system facilitated the diversification of numerous insect lineages. For instance, evolutionary changes of Odorant Receptor (OR) genes often occur in parallel with modifications in life history strategies. Corbiculate bees display a diverse array of behaviors that are controlled through olfaction, including varying degrees of social organization, and manifold associations with floral resources. Here we investigated the molecular mechanisms driving the evolution of the OR gene family in corbiculate bees in comparison to other chemosensory gene families. Our results indicate that the genomic organization of the OR gene family has remained highly conserved for ∼80 Myr, despite exhibiting major changes in repertoire size among bee lineages. Moreover, the evolution of OR genes appears to be driven mostly by lineage-specific gene duplications in few genomic regions that harbor large numbers of OR genes. A selection analysis revealed that OR genes evolve under positive selection, with the strongest signals detected in recently duplicated copies. Our results indicate that chromosomal translocations had a minimal impact on OR evolution, and instead local molecular mechanisms appear to be main drivers of OR repertoire size. Our results provide empirical support to the longstanding hypothesis that positive selection shaped the diversification of the OR gene family. Together, our results shed new light on the molecular mechanisms underlying the evolution of olfaction in insects. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  2. State Compensatory Education: Final Technical Report. Publication Number 80.72.

    ERIC Educational Resources Information Center

    Austin Independent School District, TX. Office of Research and Evaluation.

    In evaluating the Austin Independent School District's State Compensatory Education (SCE) program, the Office of Research and Evaluation looked at nine program areas. The service report examined the services teachers gave and the achievement gains made by their students. The counselor service report examined how many eligible students were served…

  3. Evaluation Report: ESEA Program of Compensatory Education (Including Abstract and Appendix).

    ERIC Educational Resources Information Center

    Badal, Alden W.

    This document is an evaluation of 1967-68 compensatory education programs in Oakland, California, funded by the Elementary and Secondary Education Act, Title I. It consists of three parts: (1) the evaluation report; (2) an appendix containing tables, questionnaire summaries, sample forms, etc.; and (3) an abstract of the total document. Reported…

  4. Fiscal Viability, Conjunctive and Compensatory Models, and Career-Ladder Decisions: An Empirical Investigation.

    ERIC Educational Resources Information Center

    Mehrens, William A.; And Others

    A study was undertaken to explore cost-effective ways of making career ladder teacher evaluation system decisions based on fewer measures, assessing the relationship of observational variables to other data and final decisions, and comparison of compensatory and conjunctive decision models. Data included multiple scores from eight data sources in…

  5. Compensatory Effects of Sibling Support in Preadolescence and Adolescence.

    ERIC Educational Resources Information Center

    Milevsky, Avidan; Levitt, Mary J.

    The current study is an examination of how support from siblings relates to academic competence in early adolescence, with a focus on the compensatory effects of sibling support. Participants were 694 African-American, European-American, and Hispanic-American students, ranging in age from 11 to 15. Participants were interviewed in school regarding…

  6. State Compensatory Education. Final Technical Report 1975-76. Appendixes.

    ERIC Educational Resources Information Center

    Austin Independent School District, TX. Office of Research and Evaluation.

    This material consists of ten appendixes to the Final Report for 1976-77 on the implementation of the Texas state-supported compensatory education program in the Austin Independent School District as evaluated by that district's Office of Research and Evaluation. The instruments used in the evaluation process are described or presented in full,…

  7. Evaluation Design: 1981-82 State Compensatory Education. Publication No. 81.20.

    ERIC Educational Resources Information Center

    Mangino, Evangelina; And Others

    The evaluation of the 1981-82 State Compensatory Education (SCE) program, as implemented in the Austin Independent School District, will involve the following major activities: production of an Evaluation Design based on input received from key SCE personnel; production of a Final Report and a Technical Report which present information and…

  8. An Investigation of the Compensatory Effectiveness of Assistive Technology on Postsecondary Students with Learning Disabilities. Final Report.

    ERIC Educational Resources Information Center

    Murphy, Harry; Higgins, Eleanor

    This final report describes the activities and accomplishments of a 3-year study on the compensatory effectiveness of three assistive technologies, optical character recognition, speech synthesis, and speech recognition, on postsecondary students (N=140) with learning disabilities. These technologies were investigated relative to: (1) immediate…

  9. Compensatory Reading among ESL Learners: A Reading Strategy Heuristic

    ERIC Educational Resources Information Center

    Ismail, Shaik Abdul Malik Mohamed; Petras, Yusof Ede; Mohamed, Abdul Rashid; Eng, Lin Siew

    2015-01-01

    This paper aims to gain an insight to the relationship of two different concepts about reading comprehension, namely, the linear model of comprehension and the interactive compensatory theory. Drawing on both the above concepts, a heuristic was constructed about three different reading strategies determined by the specific ways the literal,…

  10. GENOMIC COMPARISON OF IN VITRO AND IN VIVO EFFECTS OF ENDOCRINE DISRUPTORS ON FATHEAD MINNOW ( PIMEPHALES PROMELAS ) OVARIES REVEALS COMPENSATORY MECHANISMS

    EPA Science Inventory

    This study investigates compensatory mechanisms and feedback control within Fathead minnow (Pimephales promelas) by comparing genomic and biochemical responses of ovary tissue exposed in vitro to those of ovaries from intact fish after exposure to two model steroidogenesis...

  11. Evaluation of the Effectiveness of Compensatory Education Funded by Title I, ESEA.

    ERIC Educational Resources Information Center

    Gordon, Kenneth F.; Gordon, Barbara, J. A.

    During 1967 and 1968, TEMPO, a Research affiliate of The General Electric Company, evaluated federal assistance to local school districts to use for compensatory education authorized by 1965 Elementary Secondary Education Act Title I. The specific research questions were straight-forward: (1) Has statistically significant enhancement of pupil…

  12. Blast-induced Mild Traumatic Brain Injury

    DTIC Science & Technology

    2010-01-01

    concentration with agents such as psychostimulants, or improving compensatory strategies through cognitive- behavioral therapies. Pharmacological interventions...participate in educational activities and support groups. Some examples of general educational content include (1) compensatory strategies for impaired...or simple, ranging from electronic transmitters to trip wires, tilt switches, motion detectors, or thermal or pressure-sensitive switches. lEOs are

  13. A Dualistic Stream Classification System for Oregon: In Support of a Stream Compensatory Mitigation Framework

    EPA Science Inventory

    To meet the goals of the U.S. federal Clean Water Act (CWA) and Oregon’s Removal-Fill (R-F) Law, unavoidable impacts to jurisdictional waters, including streams and rivers, must be compensated for through compensatory mitigation under the CWA Section 404 and R-F permitting ...

  14. Controversies in the Evaluation of Compensatory Education

    ERIC Educational Resources Information Center

    McLaughlin, Donald H.; And Others

    This document answers the question, "What has been learned about evaluation methodology from the decade of compensatory education"? Ten issues dealing with the evaluation of Title I were identified within a general theoretical framework of evaluation. For each issue it was the aim of this document to do the following: 1)to clarify the…

  15. A Successful Form of Trade-Off in Compensatory Policy Classrooms

    ERIC Educational Resources Information Center

    Vors, Olivier; Gal-Petitfaux, Nathalie; Potdevin, François

    2015-01-01

    Since 2010, French middle schools with a high enrolment of difficult students have benefited from a compensatory policy called "Écoles Collèges et Lycées pour l'Ambition, l'Innovation et la Réussite" (ECLAIR) (Primary and Secondary Schools for Ambition, Innovation and Success). These difficult students frequently misbehave, disengage…

  16. A Compensatory Reading Program for the Community Junior College.

    ERIC Educational Resources Information Center

    Weiss, Lucile S.

    The purpose of this study was to determine if a compensatory reading program based on the language experience approach could raise the reading level of underachieving disadvantaged students in the community junior colleges to a level commensurate with their ability and high enough for subsequent success in college level academic courses.…

  17. Analyzing for Individual Differences in Evaluating Compensatory Education Programs. Occasional Paper No. 27.

    ERIC Educational Resources Information Center

    Krus, Patricia H.

    Trait-Treatment Interaction (TTI), a research method for observing experimental effects of treatments on subjects of different aptitudes and learning characteristics, is suggested as an effective evaluation tool to provide evaluators and educators in compensatory education programs with information about which program is best for different kinds…

  18. Bi-Factor Multidimensional Item Response Theory Modeling for Subscores Estimation, Reliability, and Classification

    ERIC Educational Resources Information Center

    Md Desa, Zairul Nor Deana

    2012-01-01

    In recent years, there has been increasing interest in estimating and improving subscore reliability. In this study, the multidimensional item response theory (MIRT) and the bi-factor model were combined to estimate subscores, to obtain subscores reliability, and subscores classification. Both the compensatory and partially compensatory MIRT…

  19. 5 CFR 532.504 - Compensatory time off.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... irregular or occasional overtime work. (b) At the request of an employee, the head of an agency may grant compensatory time off from an employee's basic work requirement under a flexible work schedule under 5 U.S.C... equal amount of overtime work, whether or not irregular or occasional in nature. (c) An agency may not...

  20. 5 CFR 550.114 - Compensatory time off.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) may grant compensatory time off from an employee's basic work requirement under a flexible work schedule under 5 U.S.C. 6122 instead of payment under § 550.113 for an equal amount of overtime work... duty instead of payment under § 550.113 for an equal amount of irregular or occasional overtime work...

  1. State Compensatory Education: 1979-80. Final Technical Report. Publication No. 79.18.

    ERIC Educational Resources Information Center

    Austin Independent School District, TX. Office of Research and Evaluation.

    A major portion of Texas' State Compensatory Education (SCE) evaluation resources for 1979-80 was devoted to activities related to the statewide assessment of fifth and ninth graders' skills in reading, mathematics, and writing (the Texas Assessment of Basic Skills Project). For purposes of this report, evaluation activity and information is…

  2. Compensatory Education in California, 1966-67. Annual Evaluation Report.

    ERIC Educational Resources Information Center

    Braund, Robert A.; And Others

    Title I of the Elementary and Secondary Education Act of 1965 is California's major source of funds for compensatory education programs designed to enhance the educational attainment of children from poverty backgrounds. The annual state evaluation report provides information on the distribution of Title I funds, the number of students served, and…

  3. Compensatory neurofuzzy model for discrete data classification in biomedical

    NASA Astrophysics Data System (ADS)

    Ceylan, Rahime

    2015-03-01

    Biomedical data is separated to two main sections: signals and discrete data. So, studies in this area are about biomedical signal classification or biomedical discrete data classification. There are artificial intelligence models which are relevant to classification of ECG, EMG or EEG signals. In same way, in literature, many models exist for classification of discrete data taken as value of samples which can be results of blood analysis or biopsy in medical process. Each algorithm could not achieve high accuracy rate on classification of signal and discrete data. In this study, compensatory neurofuzzy network model is presented for classification of discrete data in biomedical pattern recognition area. The compensatory neurofuzzy network has a hybrid and binary classifier. In this system, the parameters of fuzzy systems are updated by backpropagation algorithm. The realized classifier model is conducted to two benchmark datasets (Wisconsin Breast Cancer dataset and Pima Indian Diabetes dataset). Experimental studies show that compensatory neurofuzzy network model achieved 96.11% accuracy rate in classification of breast cancer dataset and 69.08% accuracy rate was obtained in experiments made on diabetes dataset with only 10 iterations.

  4. Effects of relational uncertainty in heightening national identification and reactive approach motivation of Japanese.

    PubMed

    Terashima, Yuto; Takai, Jiro

    2017-03-23

    This study investigated whether relational uncertainty poses uncertainty threat, which causes compensatory behaviours among Japanese. We hypothesised that Japanese, as collectivists, would perceive relational uncertainty to pose uncertainty threat. In two experiments, we manipulated relational uncertainty, and confirmed that participants exhibited compensatory reactions to reduce aversive feelings due to it. In Study 1, we conducted direct comparison between relational uncertainty, independent self-uncertainty and control conditions. The results revealed that participants who were instructed to imagine events pertaining to relational uncertainty heightened national identification as compensation than did participants in the control condition, but independent self-uncertainty did not provoke such effects. In Study 2, we again manipulated relational uncertainty; however, we also manipulated participants' individualism-collectivism cultural orientation through priming, and the analyses yielded a significant interaction effect between these variables. Relational uncertainty evoked reactive approach motivation, a cause for compensatory behaviours, among participants primed with collectivism, but not for individualism. It was concluded that the effect of uncertainty on compensatory behaviour is influenced by cultural priming, and that relational uncertainty is important to Japanese. © 2017 International Union of Psychological Science.

  5. Surgical management of anomalous head posture because of horizontal gaze palsy or acquired vertical nystagmus.

    PubMed

    Campos, E C; Schiavi, C; Bellusci, C

    2003-07-01

    To confirm the effectiveness of the Kestenbaum-Anderson principle in the surgical management of compensatory head posture because of horizontal gaze palsy and acquired vertical nystagmus. Nine patients with anomalous head posture because of horizontal gaze palsy, and four patients with acquired vertical nystagmus and oscillopsia and compensatory torticollis underwent surgery according to the Kestenbaum-Anderson principle. As in the treatment of congenital nystagmus, the eyes have to be shifted in the orbits, in the direction of anomalous head posture. Homonymously based prisms were used preoperatively to assess the potential benefit of surgery. At the time of surgery, the clinical conditions of the patients had been stable for at least 1 year. After surgery, compensatory head posture and visual performances improved in all cases and the results remained stable for at least 2 years. Contrary to what is generally believed, the ocular condition of the patients with compensatory head posture secondary to neurological causes can be often improved with surgery. The aim of surgery is obviously not to modify ocular motility, but rather to improve the head position.

  6. Compensatory growth following transient intraguild predation risk in predatory mites.

    PubMed

    Walzer, Andreas; Lepp, Natalia; Schausberger, Peter

    2015-05-01

    Compensatory or catch-up growth following growth impairment caused by transient environmental stress, due to adverse abiotic factors or food, is widespread in animals. Such growth strategies commonly balance retarded development and reduced growth. They depend on the type of stressor but are unknown for predation risk, a prime selective force shaping life history. Anti-predator behaviours by immature prey typically come at the cost of reduced growth rates with potential negative consequences on age and size at maturity. Here, we investigated the hypothesis that transient intraguild predation (IGP) risk induces compensatory or catch-up growth in the plant-inhabiting predatory mite Phytoseiulus persimilis . Immature P. persimilis were exposed in the larval stage to no, low or high IGP risk, and kept under benign conditions in the next developmental stage, the protonymph. High but not low IGP risk prolonged development of P. persimilis larvae, which was compensated in the protonymphal stage by increased foraging activity and accelerated development, resulting in optimal age and size at maturity. Our study provides the first experimental evidence that prey may balance developmental costs accruing from anti-predator behaviour by compensatory growth.

  7. Compensatory growth following transient intraguild predation risk in predatory mites

    PubMed Central

    Walzer, Andreas; Lepp, Natalia; Schausberger, Peter

    2015-01-01

    Compensatory or catch-up growth following growth impairment caused by transient environmental stress, due to adverse abiotic factors or food, is widespread in animals. Such growth strategies commonly balance retarded development and reduced growth. They depend on the type of stressor but are unknown for predation risk, a prime selective force shaping life history. Anti-predator behaviours by immature prey typically come at the cost of reduced growth rates with potential negative consequences on age and size at maturity. Here, we investigated the hypothesis that transient intraguild predation (IGP) risk induces compensatory or catch-up growth in the plant-inhabiting predatory mite Phytoseiulus persimilis. Immature P. persimilis were exposed in the larval stage to no, low or high IGP risk, and kept under benign conditions in the next developmental stage, the protonymph. High but not low IGP risk prolonged development of P. persimilis larvae, which was compensated in the protonymphal stage by increased foraging activity and accelerated development, resulting in optimal age and size at maturity. Our study provides the first experimental evidence that prey may balance developmental costs accruing from anti-predator behaviour by compensatory growth. PMID:26005221

  8. Compensatory activity in the extrastriate body area of Parkinson's disease patients.

    PubMed

    van Nuenen, Bart F L; Helmich, Rick C; Buenen, Noud; van de Warrenburg, Bart P C; Bloem, Bastiaan R; Toni, Ivan

    2012-07-11

    Compensatory mechanisms are a crucial component of the cerebral changes triggered by neurodegenerative disorders. Identifying such compensatory mechanisms requires at least two complementary approaches: localizing candidate areas using functional imaging, and showing that interference with these areas has behavioral consequences. Building on recent imaging evidence, we use this approach to test whether a visual region in the human occipito-temporal cortex-the extrastriate body area-compensates for altered dorsal premotor activity in Parkinson's disease (PD) during motor-related processes. We separately inhibited the extrastriate body area and dorsal premotor cortex in 11 PD patients and 12 healthy subjects, using continuous theta burst stimulation. Our goal was to test whether these areas are involved in motor compensatory processes. We used motor imagery to isolate a fundamental element of motor planning, namely subjects' ability to incorporate the current state of their body into a motor plan (mental hand rotation). We quantified this ability through a posture congruency effect (i.e., the improvement in subjects' performance when their current body posture is congruent to the imagined movement). Following inhibition of the right extrastriate body area, the posture congruency effect was lost in PD patients, but not in healthy subjects. In contrast, inhibition of the left dorsal premotor cortex reduced the posture congruency effect in healthy subjects, but not in PD patients. These findings suggest that the right extrastriate body area plays a compensatory role in PD by supporting a function that is no longer performed by the dorsal premotor cortex.

  9. Comparison of only T3 and T3–T4 sympathectomy for axillary hyperhidrosis regarding treatment effect and compensatory sweating

    PubMed Central

    Yuncu, Gökhan; Turk, Figen; Ozturk, Gökhan; Atinkaya, Cansel

    2013-01-01

    OBJECTIVES Patients diagnosed with axillary hyperhidrosis can face psychosocial issues that can ultimately hinder their quality of life both privately and socially. The routine treatment for axillary hyperhidrosis is T3–T4 sympathectomy, but compensatory sweating is a serious side effect that is commonly seen with this approach. This study was designed to evaluate whether a T3 sympathectomy was effective for the treatment of axillary hyperhidrosis and whether this treatment led to less compensatory sweating than T3–T4 sympathectomies among our 60-patient population. METHODS One hundred and twenty endoscopic thoracic sympathectomies were performed on 60 patients who had axillary hyperhidrosis. The sympathectomies were accomplished by means of a single-lumen endotracheal tube and a single port. The axillary hyperhidrosis patients were randomly divided into two groups with 17 patients in Group 1 undergoing T3–T4 sympathectomies and 43 in Group 2 undergoing only T3 sympathectomies. We analysed the data associated with the resolution of axillary hyperhidrosis, the degree of patient satisfaction with the surgical outcome and the quality of life in parallel with compensatory sweating after the procedure as reported by the patient and confirmed by the examiner. Moreover, the results were compared statistically. RESULTS No statistically significant difference was observed between the groups based on age (P = 0.56), gender (P = 0.81), duration of the surgery (P = 0.35) or postoperative satisfaction levels (P = 0.45). However, the incidence and degree of compensatory sweating were lower in the T3 group than the T3–T4 group at the 1-year follow-up (P = 0.008). CONCLUSIONS T3 sympathectomy was as effective as T3–T4 sympathectomy for the treatment of axillary hyperhidrosis based on the patients’ reported postoperative satisfaction, and the T3 group demonstrated lower compensatory sweating at the 1-year follow-up. PMID:23644731

  10. Preparation for Compensatory Forward Stepping in Parkinson’s Disease

    PubMed Central

    King, Laurie A.; St George, Rebecca J.; Carlson-Kuhta, Patricia; Nutt, John G.; Horak, Fay B.

    2010-01-01

    Objective To characterize preparation for compensatory stepping in people with Parkinson’s disease (PD) compared with healthy control subjects, and to determine whether levodopa medication improves preparation or the execution phases of the step. Design Observational study. Setting Outpatient neuroscience laboratory. Participants Nineteen participants with idiopathic PD tested both in the on and off levodopa states and 17 healthy subjects. Intervention Moveable platform with posterior translations of 24cm at 56cm/s. Main Outcome Measures Compensatory steps forward, in response to a backward surface translation (24cm amplitude at 56cm/s), were categorized according to the presence of an anticipatory postural adjustment (APA) before stepping: no APA, single APA, or multiple APAs. The following step parameters were calculated: step latency, step length, center of mass (CoM) average velocity, and CoM displacement at the step initiation. Results Lateral APAs were evident in 57% and 42% of trials for people with PD in the off and on medication states, respectively, compared with only 10% of trials for control subjects. Compared with subjects with PD who did not have APAs, those subjects with PD who did make an APA prior to stepping had significantly later (mean ± SEM, 356 ± 16ms vs 305 ± 8ms) and shorter (mean ± SEM, 251 ± 27mm vs 300 ± 16mm) steps, their CoM was significantly farther forward (185 ± 7mm vs 171 ± 5mm) at foot-off, and they took significantly more steps to regain equilibrium. Levodopa did not affect the preparation or execution phase of compensatory stepping. Poor axial scores and reports of freezing in the United Parkinson’s Disease Rating Scale were associated with use of 1 or more APAs before compensatory stepping. Conclusions Lateral postural preparation prior to compensatory stepping in subjects with PD was associated with inefficient balance recovery from external perturbations. PMID:20801249

  11. Does age matter? Age and rehabilitation of visual field disorders after brain injury.

    PubMed

    Schuett, Susanne; Zihl, Josef

    2013-04-01

    Homonymous visual field disorders (HVFD) are frequent and disabling consequences of acquired brain injury, particularly in older age. Their rehabilitation is therefore of great importance. Compensatory oculomotor therapy has been found to be effective in improving the associated functional impairments in reading and visual exploration. But older age is commonly considered to adversely affect practice-dependent functional plasticity and, thus, functional and rehabilitation outcome after acquired brain injury. The effect of age in the compensatory treatment of HVFD, however, has never been investigated hitherto. It remains unknown whether age determines not only patients' functional impairments but also the rehabilitation outcome and the required amount of treatment. We therefore present the first study to determine the effect of age in 38 patients with HVFD receiving compensatory oculomotor treatment for their reading and visual exploration impairments. We investigated whether older patients with HVFD (1) show more pronounced impairments and less spontaneous adaptation, (2) show lesser compensatory treatment-related improvement in reading and visual exploration, and (3) require a higher amount of treatment than younger patients. Our main finding is that older patients achieve the same treatment-induced improvements in reading and visual exploration with the same amount of treatment as younger patients; severity of functional impairment also did not differ between older and younger patients, at least in reading. Age does not seem to be a critical factor determining the functional and rehabilitation outcome in the compensatory treatment of HVFD. Older age per se is not necessarily associated with a decline in practice-dependent functional plasticity and adaptation. To the contrary, the effectiveness of compensatory treatment to reduce the functional impairments to a similar extent in younger and older patients with HVFD adds to the growing evidence for a life-long potential for adaptation to the adverse effects of brain injury. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Index of cerebrospinal compensatory reserve in hydrocephalus.

    PubMed

    Kim, Dong-Joo; Czosnyka, Zofia; Keong, Nicole; Radolovich, Danila K; Smielewski, Peter; Sutcliffe, Michael P F; Pickard, John D; Czosnyka, Marek

    2009-03-01

    An index of cerebrospinal compensatory reserve (RAP) has been introduced as a potential descriptor of neurological deterioration after head trauma. It is numerically computed as a linear correlation coefficient between the mean intracranial pressure and the pulse amplitude of the pressure waveform. We explore how RAP varies with different forms of physiological or nonphysiological intracranial volume loads in adult hydrocephalus, with and without a functioning cerebrospinal fluid (CSF) shunt. A database of intracranial pressure recordings during CSF infusion studies and overnight monitoring in hydrocephalic patients was reviewed for clinical comparison of homogeneous subgroups of patients with hypothetical differences of pressure-volume compensatory reserve. The database includes 980 patients of mixed etiology: idiopathic normal pressure hydrocephalus (NPH), 47%; postsubarachnoid hemorrhage NPH, 12%; noncommunicating hydrocephalus, 22%; others, 19%. All CSF compensatory parameters were calculated by using intracranial pressure waveforms. In NPH, RAP correlated strongly with the resistance to CSF outflow (r(s) = 0.35; P = 0.045), but weakly correlated with ventriculomegaly (r(s) = 0.13; P = 0.41). In idiopathic nonshunted NPH patients, RAP did not correlate significantly with elasticity calculated from the CSF infusion test (r(s) = 0.11; P = 0.21). During infusion studies, RAP increased in comparison to values recorded at baseline (from a median of 0.45-0.86, P = 0.14 * 10(-8)), indicating a narrowing of the volume-pressure compensatory reserve. During B-waves associated with the REM (rapid eye movement) phase of sleep, RAP increased from a median of 0.53 to 0.89; P = 1.2 * 10(-5). After shunting, RAP decreased (median before shunting, 0.59; median after shunting, 0.34; P = 0.0001). RAP also showed the ability to reflect the functional state of the shunt (patent shunt median, 0.36; blocked shunt median, 0.84; P = 0.0002). RAP appears to characterize pressure-volume compensatory reserve in patients with hydrocephalus.

  13. Photoionization-regulated star formation and the structure of molecular clouds

    NASA Technical Reports Server (NTRS)

    Mckee, Christopher F.

    1989-01-01

    A model for the rate of low-mass star formation in Galactic molecular clouds and for the influence of this star formation on the structure and evolution of the clouds is presented. The rate of energy injection by newly formed stars is estimated, and the effect of this energy injection on the size of the cloud is determined. It is shown that the observed rate of star formation appears adequate to support the observed clouds against gravitational collapse. The rate of photoionization-regulated star formation is estimated and it is shown to be in agreement with estimates of the observed rate of star formation if the observed molecular cloud parameters are used. The mean cloud extinction and the Galactic star formation rate per unit mass of molecular gas are predicted theoretically from the condition that photionization-regulated star formation be in equilibrium. A simple model for the evolution of isolated molecular clouds is developed.

  14. [A group of new experiments on molecular evolution].

    PubMed

    Zhu, Xin-Yu; Xie, Xiao-Ling; Chen, Pei-Lin

    2004-07-01

    This paper presents a group of new experiments on molecular evolution. It allows students to get acquaint with the basic process of the reconstruction of phylogenetic tree using DNA or protein sequences, and to acquire the correct viewpoint how to affect the result of reconstruction when different tree-building methods, materials and parameters were used. This group of experiments are also characteristic of the opening and exploring, which accords with the direction and demand of experimental teaching reform.

  15. Comparative Genomics Reveals Accelerated Evolution in Conserved Pathways during the Diversification of Anole Lizards.

    PubMed

    Tollis, Marc; Hutchins, Elizabeth D; Stapley, Jessica; Rupp, Shawn M; Eckalbar, Walter L; Maayan, Inbar; Lasku, Eris; Infante, Carlos R; Dennis, Stuart R; Robertson, Joel A; May, Catherine M; Crusoe, Michael R; Bermingham, Eldredge; DeNardo, Dale F; Hsieh, Shi-Tong Tonia; Kulathinal, Rob J; McMillan, William Owen; Menke, Douglas B; Pratt, Stephen C; Rawls, Jeffery Alan; Sanjur, Oris; Wilson-Rawls, Jeanne; Wilson Sayres, Melissa A; Fisher, Rebecca E; Kusumi, Kenro

    2018-02-01

    Squamates include all lizards and snakes, and display some of the most diverse and extreme morphological adaptations among vertebrates. However, compared with birds and mammals, relatively few resources exist for comparative genomic analyses of squamates, hampering efforts to understand the molecular bases of phenotypic diversification in such a speciose clade. In particular, the ∼400 species of anole lizard represent an extensive squamate radiation. Here, we sequence and assemble the draft genomes of three anole species-Anolis frenatus, Anolis auratus, and Anolis apletophallus-for comparison with the available reference genome of Anolis carolinensis. Comparative analyses reveal a rapid background rate of molecular evolution consistent with a model of punctuated equilibrium, and strong purifying selection on functional genomic elements in anoles. We find evidence for accelerated evolution in genes involved in behavior, sensory perception, and reproduction, as well as in genes regulating limb bud development and hindlimb specification. Morphometric analyses of anole fore and hindlimbs corroborated these findings. We detect signatures of positive selection across several genes related to the development and regulation of the forebrain, hormones, and the iguanian lizard dewlap, suggesting molecular changes underlying behavioral adaptations known to reinforce species boundaries were a key component in the diversification of anole lizards. © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  16. Sporadic renal angiomyolipoma in a patient with Birt-Hogg-Dubé: chaperones in pathogenesis.

    PubMed

    Sager, Rebecca A; Woodford, Mark R; Shapiro, Oleg; Mollapour, Mehdi; Bratslavsky, Gennady

    2018-04-24

    Birt-Hogg-Dubé (BHD) is an autosomal dominant genetic syndrome caused by germline mutations in the FLCN gene that predisposes patients to develop renal tumors. Renal angiomyolipoma (AML) is not a renal tumor sub-type associated with BHD. AML is, however, a common phenotypic manifestation of Tuberous Sclerosis Complex (TSC) syndrome caused by mutations in either the TSC1 or TSC2 tumor suppressor genes. Previous case reports of renal AML in patients with BHD have speculated on the molecular and clinical overlap of these two syndromes as a result of described involvement of the gene products in the mTOR pathway. Our recent work provided a new molecular link between these two syndromes by identifying FLCN and Tsc2 as clients of the molecular chaperone Hsp90. Folliculin interacting proteins FNIP1/2 and Tsc1 are important for FLCN and Tsc2 stability as new Hsp90 co-chaperones. Here we present a case of sporadic AML as a result of somatic Tsc1/2 loss in a patient with BHD. We further demonstrate that FNIP1 and Tsc1 are capable of compensating for each other in the chaperoning of mutated FLCN tumor suppressor. Our findings demonstrate interconnectivity and compensatory mechanisms between the BHD and TSC pathways.

  17. Towards a system level understanding of non-model organisms sampled from the environment: a network biology approach.

    PubMed

    Williams, Tim D; Turan, Nil; Diab, Amer M; Wu, Huifeng; Mackenzie, Carolynn; Bartie, Katie L; Hrydziuszko, Olga; Lyons, Brett P; Stentiford, Grant D; Herbert, John M; Abraham, Joseph K; Katsiadaki, Ioanna; Leaver, Michael J; Taggart, John B; George, Stephen G; Viant, Mark R; Chipman, Kevin J; Falciani, Francesco

    2011-08-01

    The acquisition and analysis of datasets including multi-level omics and physiology from non-model species, sampled from field populations, is a formidable challenge, which so far has prevented the application of systems biology approaches. If successful, these could contribute enormously to improving our understanding of how populations of living organisms adapt to environmental stressors relating to, for example, pollution and climate. Here we describe the first application of a network inference approach integrating transcriptional, metabolic and phenotypic information representative of wild populations of the European flounder fish, sampled at seven estuarine locations in northern Europe with different degrees and profiles of chemical contaminants. We identified network modules, whose activity was predictive of environmental exposure and represented a link between molecular and morphometric indices. These sub-networks represented both known and candidate novel adverse outcome pathways representative of several aspects of human liver pathophysiology such as liver hyperplasia, fibrosis, and hepatocellular carcinoma. At the molecular level these pathways were linked to TNF alpha, TGF beta, PDGF, AGT and VEGF signalling. More generally, this pioneering study has important implications as it can be applied to model molecular mechanisms of compensatory adaptation to a wide range of scenarios in wild populations.

  18. Towards a System Level Understanding of Non-Model Organisms Sampled from the Environment: A Network Biology Approach

    PubMed Central

    Williams, Tim D.; Turan, Nil; Diab, Amer M.; Wu, Huifeng; Mackenzie, Carolynn; Bartie, Katie L.; Hrydziuszko, Olga; Lyons, Brett P.; Stentiford, Grant D.; Herbert, John M.; Abraham, Joseph K.; Katsiadaki, Ioanna; Leaver, Michael J.; Taggart, John B.; George, Stephen G.; Viant, Mark R.; Chipman, Kevin J.; Falciani, Francesco

    2011-01-01

    The acquisition and analysis of datasets including multi-level omics and physiology from non-model species, sampled from field populations, is a formidable challenge, which so far has prevented the application of systems biology approaches. If successful, these could contribute enormously to improving our understanding of how populations of living organisms adapt to environmental stressors relating to, for example, pollution and climate. Here we describe the first application of a network inference approach integrating transcriptional, metabolic and phenotypic information representative of wild populations of the European flounder fish, sampled at seven estuarine locations in northern Europe with different degrees and profiles of chemical contaminants. We identified network modules, whose activity was predictive of environmental exposure and represented a link between molecular and morphometric indices. These sub-networks represented both known and candidate novel adverse outcome pathways representative of several aspects of human liver pathophysiology such as liver hyperplasia, fibrosis, and hepatocellular carcinoma. At the molecular level these pathways were linked to TNF alpha, TGF beta, PDGF, AGT and VEGF signalling. More generally, this pioneering study has important implications as it can be applied to model molecular mechanisms of compensatory adaptation to a wide range of scenarios in wild populations. PMID:21901081

  19. Diversified Structural Basis of a Conserved Molecular Mechanism for pH-Dependent Dimerization in Spider Silk N-Terminal Domains.

    PubMed

    Otikovs, Martins; Chen, Gefei; Nordling, Kerstin; Landreh, Michael; Meng, Qing; Jörnvall, Hans; Kronqvist, Nina; Rising, Anna; Johansson, Jan; Jaudzems, Kristaps

    2015-08-17

    Conversion of spider silk proteins from soluble dope to insoluble fibers involves pH-dependent dimerization of the N-terminal domain (NT). This conversion is tightly regulated to prevent premature precipitation and enable rapid silk formation at the end of the duct. Three glutamic acid residues that mediate this process in the NT from Euprosthenops australis major ampullate spidroin 1 are well conserved among spidroins. However, NTs of minor ampullate spidroins from several species, including Araneus ventricosus ((Av)MiSp NT), lack one of the glutamic acids. Here we investigate the pH-dependent structural changes of (Av)MiSp NT, revealing that it uses the same mechanism but involves a non-conserved glutamic acid residue instead. Homology modeling of the structures of other MiSp NTs suggests that these harbor different compensatory residues. This indicates that, despite sequence variations, the molecular mechanism underlying pH-dependent dimerization of NT is conserved among different silk types. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. The evolution, morphology, and development of fern leaves

    PubMed Central

    Vasco, Alejandra; Moran, Robbin C.; Ambrose, Barbara A.

    2013-01-01

    Leaves are lateral determinate structures formed in a predictable sequence (phyllotaxy) on the flanks of an indeterminate shoot apical meristem. The origin and evolution of leaves in vascular plants has been widely debated. Being the main conspicuous organ of nearly all vascular plants and often easy to recognize as such, it seems surprising that leaves have had multiple origins. For decades, morphologists, anatomists, paleobotanists, and systematists have contributed data to this debate. More recently, molecular genetic studies have provided insight into leaf evolution and development mainly within angiosperms and, to a lesser extent, lycophytes. There has been recent interest in extending leaf evolutionary developmental studies to other species and lineages, particularly in lycophytes and ferns. Therefore, a review of fern leaf morphology, evolution and development is timely. Here we discuss the theories of leaf evolution in ferns, morphology, and diversity of fern leaves, and experimental results of fern leaf development. We summarize what is known about the molecular genetics of fern leaf development and what future studies might tell us about the evolution of fern leaf development. PMID:24027574

  1. Molecular evolution of the clustered MMIC-3 multigene family of Gossypium species

    USDA-ARS?s Scientific Manuscript database

    Uniqueness, content, localization, and defense-related features of the root-knot nematode resistance-associated MIC-3 supergene cluster in the genus Gossypium are all of interest for molecular evolutionary studies of duplicate supergenes in allopolyploids. Here we report molecular evolutionary rates...

  2. Epistasis increases the rate of conditionally neutral substitution in an adapting population.

    PubMed

    Draghi, Jeremy A; Parsons, Todd L; Plotkin, Joshua B

    2011-04-01

    Kimura observed that the rate of neutral substitution should equal the neutral mutation rate. This classic result is central to our understanding of molecular evolution, and it continues to influence phylogenetics, genomics, and the interpretation of evolution experiments. By demonstrating that neutral mutations substitute at a rate independent of population size and selection at linked sites, Kimura provided an influential justification for the idea of a molecular clock and emphasized the importance of genetic drift in shaping molecular evolution. But when epistasis among sites is common, as numerous empirical studies suggest, do neutral mutations substitute according to Kimura's expectation? Here we study simulated, asexual populations of RNA molecules, and we observe that conditionally neutral mutations--i.e., mutations that do not alter the fitness of the individual in which they arise, but that may alter the fitness effects of subsequent mutations--substitute much more often than expected while a population is adapting. We quantify these effects using a simple population-genetic model that elucidates how the substitution rate at conditionally neutral sites depends on the population size, mutation rate, strength of selection, and prevalence of epistasis. We discuss the implications of these results for our understanding of the molecular clock, and for the interpretation of molecular variation in laboratory and natural populations.

  3. Epistasis Increases the Rate of Conditionally Neutral Substitution in an Adapting Population

    PubMed Central

    Draghi, Jeremy A.; Parsons, Todd L.; Plotkin, Joshua B.

    2011-01-01

    Kimura observed that the rate of neutral substitution should equal the neutral mutation rate. This classic result is central to our understanding of molecular evolution, and it continues to influence phylogenetics, genomics, and the interpretation of evolution experiments. By demonstrating that neutral mutations substitute at a rate independent of population size and selection at linked sites, Kimura provided an influential justification for the idea of a molecular clock and emphasized the importance of genetic drift in shaping molecular evolution. But when epistasis among sites is common, as numerous empirical studies suggest, do neutral mutations substitute according to Kimura's expectation? Here we study simulated, asexual populations of RNA molecules, and we observe that conditionally neutral mutations—i.e., mutations that do not alter the fitness of the individual in which they arise, but that may alter the fitness effects of subsequent mutations—substitute much more often than expected while a population is adapting. We quantify these effects using a simple population-genetic model that elucidates how the substitution rate at conditionally neutral sites depends on the population size, mutation rate, strength of selection, and prevalence of epistasis. We discuss the implications of these results for our understanding of the molecular clock, and for the interpretation of molecular variation in laboratory and natural populations. PMID:21288876

  4. Adaptive Changes in the Vestibular System of Land Snail to a 30-Day Spaceflight and Readaptation on Return to Earth.

    PubMed

    Aseyev, Nikolay; Vinarskaya, Alia Kh; Roshchin, Matvey; Korshunova, Tatiana A; Malyshev, Aleksey Yu; Zuzina, Alena B; Ierusalimsky, Victor N; Lemak, Maria S; Zakharov, Igor S; Novikov, Ivan A; Kolosov, Peter; Chesnokova, Ekaterina; Volkova, Svetlana; Kasianov, Artem; Uroshlev, Leonid; Popova, Yekaterina; Boyle, Richard D; Balaban, Pavel M

    2017-01-01

    The vestibular system receives a permanent influence from gravity and reflexively controls equilibrium. If we assume gravity has remained constant during the species' evolution, will its sensory system adapt to abrupt loss of that force? We address this question in the land snail Helix lucorum exposed to 30 days of near weightlessness aboard the Bion-M1 satellite, and studied geotactic behavior of postflight snails, differential gene expressions in statocyst transcriptome, and electrophysiological responses of mechanoreceptors to applied tilts. Each approach revealed plastic changes in the snail's vestibular system assumed in response to spaceflight. Absence of light during the mission also affected statocyst physiology, as revealed by comparison to dark-conditioned control groups. Readaptation to normal tilt responses occurred at ~20 h following return to Earth. Despite the permanence of gravity, the snail responded in a compensatory manner to its loss and readapted once gravity was restored.

  5. Avian genomics lends insights into endocrine function in birds.

    PubMed

    Mello, C V; Lovell, P V

    2018-01-15

    The genomics era has brought along the completed sequencing of a large number of bird genomes that cover a broad range of the avian phylogenetic tree (>30 orders), leading to major novel insights into avian biology and evolution. Among recent findings, the discovery that birds lack a large number of protein coding genes that are organized in highly conserved syntenic clusters in other vertebrates is very intriguing, given the physiological importance of many of these genes. A considerable number of them play prominent endocrine roles, suggesting that birds evolved compensatory genetic or physiological mechanisms that allowed them to survive and thrive in spite of these losses. While further studies are needed to establish the exact extent of avian gene losses, these findings point to birds as potentially highly relevant model organisms for exploring the genetic basis and possible therapeutic approaches for a wide range of endocrine functions and disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Clostridium difficile infection: Evolution, phylogeny and molecular epidemiology.

    PubMed

    Elliott, Briony; Androga, Grace O; Knight, Daniel R; Riley, Thomas V

    2017-04-01

    Over the recent decades, Clostridium difficile infection (CDI) has emerged as a global public health threat. Despite growing attention, C. difficile remains a poorly understood pathogen, however, the exquisite sensitivity offered by next generation sequencing (NGS) technology has enabled analysis of the genome of C. difficile, giving us access to massive genomic data on factors such as virulence, evolution, and genetic relatedness within C. difficile groups. NGS has also demonstrated excellence in investigations of outbreaks and disease transmission, in both small and large-scale applications. This review summarizes the molecular epidemiology, evolution, and phylogeny of C. difficile, one of the most important pathogens worldwide in the current antibiotic resistance era. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Proceedings: Conference on Compensatory/Remedial Education, May 16 and 17, 1974. Occasional Paper No. 23.

    ERIC Educational Resources Information Center

    Fea, Henry R., Ed.; And Others

    Two papers given at a conference on compensatory/remedial education are provided. The first paper, "How to Plan a Developmental English Program with College-Wide Cooperation" by Edith A. Freligh, discusses the hypothesis that certain kinds of personalities are attracted to certain kinds of disciplines, applying it to teachers, students, and…

  8. Evaluation of the 1987-1988 EIA Remedial and Compensatory Program.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Research.

    Evaluation of South Carolina's 1987-88 Remedial and Compensatory Program, funded by the state's Education Improvement Act of 1984 (EIA), shows that the program was successful in raising the participants' achievement. The programs include basic skills learning in reading and mathematics in all grades, and writing in grades 6-12, but not all grades…

  9. Investigating the Role of Life Status Changes and Negative Emotions in Compensatory Consumption among College Students

    ERIC Educational Resources Information Center

    Yurchisin, Jennifer; Yan, Ruoh-Nan; Watchravesringkan, Kittichai; Chen, Cuiping

    2008-01-01

    The purpose of our research is to investigate whether a relationship exists between life status changes, negative emotional state, and compensatory consumption among college students. Undergraduates from four states completed a questionnaire which assessed the degree to which they were experiencing both life status changes and negative emotional…

  10. The Compensatory Effectiveness of the Quicktionary Reading Pen II on the Reading Comprehension of Students with Learning Disabilities

    ERIC Educational Resources Information Center

    Higgins, Eleanor L.; Raskind, Marshall H.

    2005-01-01

    The study investigated the compensatory effectiveness of the Quicktionary Reading Pen II (the Reading Pen), a portable device with miniaturized optical character recognition and speech synthesis capabilities. Thirty participants with reading disabilities aged 10-18 were trained on the operation of the technology and given two weeks to practice…

  11. Modeling and Compensatory Processes Underlying Involvement in Child Care among Kibbutz-Reared Fathers

    ERIC Educational Resources Information Center

    Gaunt, Ruth; Bassi, Liat

    2012-01-01

    This study examined modeling and compensatory processes underlying the effects of an early paternal model on father involvement in child care. Drawing on social learning theory, it was hypothesized that father-son relationships would moderate the association between a father's involvement and his own father's involvement. A sample of 136 kibbutz…

  12. 43 CFR 3100.2-2 - Drilling and production or payment of compensatory royalty.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL AND GAS LEASING Onshore Oil and Gas Leasing: General § 3100.2-2 Drilling and production or payment of compensatory... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Drilling and production or payment of...

  13. 43 CFR 3100.2-2 - Drilling and production or payment of compensatory royalty.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL AND GAS LEASING Onshore Oil and Gas Leasing: General § 3100.2-2 Drilling and production or payment of compensatory... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Drilling and production or payment of...

  14. 43 CFR 3100.2-2 - Drilling and production or payment of compensatory royalty.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL AND GAS LEASING Onshore Oil and Gas Leasing: General § 3100.2-2 Drilling and production or payment of compensatory... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Drilling and production or payment of...

  15. 78 FR 59753 - Public Notice for Waiver of Aeronautical Land-Use Assurance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-27

    ... aeronautical use of the property (to become effective after the sale to the Village of Schiller Park) is to be incorporated into a joint storm water detention/compensatory storage facility. The City of Chicago (City) will reserve an easement in the property for compensatory storage of storm water. DATES: Comments must be...

  16. Practice Brief: Assessing Compensatory Strategies and Motivational Factors in High-Achieving Postsecondary Students with Attention Deficit/Hyperactivity Disorder

    ERIC Educational Resources Information Center

    Schaffer, Gary

    2013-01-01

    Research speculates that high-achieving college students with attention deficit/hyperactivity disorder (ADHD) may demonstrate a set of compensatory strategies and experience areas of difficulty and motivational factors that differ from the general ADHD populace. This Practice Brief used informal surveys with seven undergraduates with ADHD who had…

  17. 17 CFR 230.701 - Exemption for offers and sales of securities pursuant to certain compensatory benefit plans and...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... RULES AND REGULATIONS, SECURITIES ACT OF 1933 Regulation E-Exemption for Securities of Small Business... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Exemption for offers and sales of securities pursuant to certain compensatory benefit plans and contracts relating to compensation...

  18. An Ultrasonographic Investigation of Cleft-Type Compensatory Articulations of Voiceless Velar Stops

    ERIC Educational Resources Information Center

    Bressmann, Tim; Radovanovic, Bojana; Kulkarni, Gajanan V.; Klaiman, Paula; Fisher, David

    2011-01-01

    Ultrasound imaging was used to investigate the articulation of the voiceless velar stop [k] in five speakers with compensatory articulation related to cleft palate. The perceptual evaluation of the acoustic realization and the visual assessment of the tongue movement for the target sound were made by three examiners. The analysis revealed a…

  19. Compensatory Weight Control Behaviors of Women in Emerging Adulthood: Associations between Childhood Abuse Experiences and Adult Relationship Avoidance

    ERIC Educational Resources Information Center

    Bankoff, Sarah M.; Valentine, Sarah E.; Jackson, Michelle A.; Schacht, Rebecca L.; Pantalone, David W.

    2013-01-01

    Objective: To examine correlates of compensatory weight control behaviors among women in transition between adolescence and adulthood. Participants: The authors recruited a sample of undergraduate women ("N" = 759) at a large northwestern university during the 2009-2010 academic year. Methods: Logistic regression was used to assess…

  20. Effect of cognitive behavior therapy on smokers' compensatory coping skills.

    PubMed

    Thorndike, Frances P; Friedman-Wheeler, Dara G; Haaga, David A F

    2006-09-01

    Cognitive behavior therapy for depression has been adapted for use in cigarette smoking cessation groups. CBT appears to be an effective treatment, though results are mixed as to whether it is especially helpful for smokers vulnerable to depression, and little is known about what mediates its effects. Based on the hypothesis that CBT works by way of teaching compensatory skills for coping with negative thinking and emotions, this study compared CBT with a time-matched comparison condition incorporating health education and scheduled, reduced smoking. There was a nonsignificant trend favoring CBT in achieving abstinence, but CBT did not enhance smokers' compensatory coping skills. Discussion focuses on the need to examine a wide range of possible mediating variables in future research on CBT for smoking cessation.

  1. Nondegenerative Evolution in Ancient Heritable Bacterial Endosymbionts of Fungi.

    PubMed

    Mondo, Stephen J; Salvioli, Alessandra; Bonfante, Paola; Morton, Joseph B; Pawlowska, Teresa E

    2016-09-01

    Bacterial endosymbionts are critical to the existence of many eukaryotes. Among them, vertically transmitted endobacteria are uniquely typified by reduced genomes and molecular evolution rate acceleration relative to free-living taxa. These patterns are attributable to genetic drift-dominated degenerative processes associated with reproductive dependence on the host. The degenerative evolution scenario is well supported in endobacteria with strict vertical transmission, such as essential mutualists of insects. In contrast, heritable endosymbionts that are nonessential to their hosts and engage occasionally in horizontal transmission are expected to display deviations from the degenerative evolution model. To explore evolution patterns in such nonessential endobacteria, we focused on Candidatus Glomeribacter gigasporarum ancient heritable mutualists of fungi. Using a collection of genomes, we estimated in Glomeribacter mutation rate at 2.03 × 10(-9) substitutions per site per year and effective population size at 1.44 × 10(8) Both fall within the range of values observed in free-living bacteria. To assess the ability of Glomeribacter to purge slightly deleterious mutations, we examined genome-wide dN/dS values and distribution patterns. We found that these dN/dS profiles cluster Glomeribacter with free-living bacteria as well as with other nonessential endosymbionts, while distinguishing it from essential heritable mutualists of insects. Finally, our evolutionary simulations revealed that the molecular evolution rate acceleration in Glomeribacter is caused by limited recombination in a largely clonal population rather than by increased fixation of slightly deleterious mutations. Based on these patterns, we propose that genome evolution in Glomeribacter is nondegenerative and exemplifies a departure from the model of degenerative evolution in heritable endosymbionts. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. The functional basis of adaptive evolution in chemostats.

    PubMed

    Gresham, David; Hong, Jungeui

    2015-01-01

    Two of the central problems in biology are determining the molecular basis of adaptive evolution and understanding how cells regulate their growth. The chemostat is a device for culturing cells that provides great utility in tackling both of these problems: it enables precise control of the selective pressure under which organisms evolve and it facilitates experimental control of cell growth rate. The aim of this review is to synthesize results from studies of the functional basis of adaptive evolution in long-term chemostat selections using Escherichia coli and Saccharomyces cerevisiae. We describe the principle of the chemostat, provide a summary of studies of experimental evolution in chemostats, and use these studies to assess our current understanding of selection in the chemostat. Functional studies of adaptive evolution in chemostats provide a unique means of interrogating the genetic networks that control cell growth, which complements functional genomic approaches and quantitative trait loci (QTL) mapping in natural populations. An integrated approach to the study of adaptive evolution that accounts for both molecular function and evolutionary processes is critical to advancing our understanding of evolution. By renewing efforts to integrate these two research programs, experimental evolution in chemostats is ideally suited to extending the functional synthesis to the study of genetic networks. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

  3. Teaching Molecular Biology with Microcomputers.

    ERIC Educational Resources Information Center

    Reiss, Rebecca; Jameson, David

    1984-01-01

    Describes a series of computer programs that use simulation and gaming techniques to present the basic principles of the central dogma of molecular genetics, mutation, and the genetic code. A history of discoveries in molecular biology is presented and the evolution of these computer assisted instructional programs is described. (MBR)

  4. Evolution of Vision

    NASA Astrophysics Data System (ADS)

    Ostrovsky, Mikhail

    The evolution of photoreception, giving rise to eye, offers a kaleidoscopic view on selection acting at both the organ and molecular levels. The molecular level is mainly considered in the lecture. The greatest progress to date has been made in relation to the opsin visual pigments. Opsins appeared before eyes did. Two- and three-dimensional organization for rhodopsin in the rod outer segment disk membrane, as well as molecular mechanisms of visual pigments spectral tuning, photoisomerization and also opsin as a G-protein coupled receptor are considered. Molecular mechanisms of visual pigments spectral tuning, namely switching of chromophore (physiological time scale) and amino acid changes in the chromophore site of opsin (evolutionary time scale) is considered in the lecture. Photoisomerization of rhodopsin chromophore, 11-cis retinal is the only photochemical reaction in vision. The reaction is extemely fast (less that 200 fs) and high efficient (. is 0.65). The rhodopsin photolysis and kinetics of the earlier products appearance, photo- and bathorhodopsin, is considered. It is known that light is not only a carrier of information, but also a risk factor of damage to the eye. This photobiological paradox of vision is mainly due to the nature of rhodopsin chromophore. Photooxidation is the base of the paradox. All factors present in the phototrceptor cells to initiate free-radical photooxidation: photosensitizers, oxygen and substrates of oxidation: lipids and proteins (opsin). That is why photoprotective system of the eye structures appeared in the course of evolution. Three lines of protective system to prevent light damage to the retina and retina pigment epithelium is known: permanent renewal of rod and cone outer segment, powerful antioxidant system and optical media as cut-off filters where the lens is a key component. The molecular mechanisms of light damage to the eye and photoprotective system of the eye is considered in the lecture. The molecular mechanisms of phototransduction in vertebrates eye is also briefly considered in the lecture. Evolution of vision is an enormous subject for thought and investigation. In the postgenomic era evolutionary molecular physiology as a whole and evolutionary molecular physiology of vision can be considered as a key approach for understanding how genome is working.

  5. Mobile DNA and evolution in the 21st century

    PubMed Central

    2010-01-01

    Scientific history has had a profound effect on the theories of evolution. At the beginning of the 21st century, molecular cell biology has revealed a dense structure of information-processing networks that use the genome as an interactive read-write (RW) memory system rather than an organism blueprint. Genome sequencing has documented the importance of mobile DNA activities and major genome restructuring events at key junctures in evolution: exon shuffling, changes in cis-regulatory sites, horizontal transfer, cell fusions and whole genome doublings (WGDs). The natural genetic engineering functions that mediate genome restructuring are activated by multiple stimuli, in particular by events similar to those found in the DNA record: microbial infection and interspecific hybridization leading to the formation of allotetraploids. These molecular genetic discoveries, plus a consideration of how mobile DNA rearrangements increase the efficiency of generating functional genomic novelties, make it possible to formulate a 21st century view of interactive evolutionary processes. This view integrates contemporary knowledge of the molecular basis of genetic change, major genome events in evolution, and stimuli that activate DNA restructuring with classical cytogenetic understanding about the role of hybridization in species diversification. PMID:20226073

  6. Social molecular pathways and the evolution of bee societies

    PubMed Central

    Bloch, Guy; Grozinger, Christina M.

    2011-01-01

    Bees provide an excellent model with which to study the neuronal and molecular modifications associated with the evolution of sociality because relatively closely related species differ profoundly in social behaviour, from solitary to highly social. The recent development of powerful genomic tools and resources has set the stage for studying the social behaviour of bees in molecular terms. We review ‘ground plan’ and ‘genetic toolkit’ models which hypothesize that discrete pathways or sets of genes that regulate fundamental behavioural and physiological processes in solitary species have been co-opted to regulate complex social behaviours in social species. We further develop these models and propose that these conserved pathways and genes may be incorporated into ‘social pathways’, which consist of relatively independent modules involved in social signal detection, integration and processing within the nervous and endocrine systems, and subsequent behavioural outputs. Modifications within modules or in their connections result in the evolution of novel behavioural patterns. We describe how the evolution of pheromonal regulation of social pathways may lead to the expression of behaviour under new social contexts, and review plasticity in circadian rhythms as an example for a social pathway with a modular structure. PMID:21690132

  7. Contrasting Levels of Molecular Evolution on the Mouse X Chromosome

    PubMed Central

    Larson, Erica L.; Vanderpool, Dan; Keeble, Sara; Zhou, Meng; Sarver, Brice A. J.; Smith, Andrew D.; Dean, Matthew D.; Good, Jeffrey M.

    2016-01-01

    The mammalian X chromosome has unusual evolutionary dynamics compared to autosomes. Faster-X evolution of spermatogenic protein-coding genes is known to be most pronounced for genes expressed late in spermatogenesis, but it is unclear if these patterns extend to other forms of molecular divergence. We tested for faster-X evolution in mice spanning three different forms of molecular evolution—divergence in protein sequence, gene expression, and DNA methylation—across different developmental stages of spermatogenesis. We used FACS to isolate individual cell populations and then generated cell-specific transcriptome profiles across different stages of spermatogenesis in two subspecies of house mice (Mus musculus), thereby overcoming a fundamental limitation of previous studies on whole tissues. We found faster-X protein evolution at all stages of spermatogenesis and faster-late protein evolution for both X-linked and autosomal genes. In contrast, there was less expression divergence late in spermatogenesis (slower late) on the X chromosome and for autosomal genes expressed primarily in testis (testis-biased). We argue that slower-late expression divergence reflects strong regulatory constraints imposed during this critical stage of sperm development and that these constraints are particularly acute on the tightly regulated sex chromosomes. We also found slower-X DNA methylation divergence based on genome-wide bisulfite sequencing of sperm from two species of mice (M. musculus and M. spretus), although it is unclear whether slower-X DNA methylation reflects development constraints in sperm or other X-linked phenomena. Our study clarifies key differences in patterns of regulatory and protein evolution across spermatogenesis that are likely to have important consequences for mammalian sex chromosome evolution, male fertility, and speciation. PMID:27317678

  8. In the Beginning was a Mutualism - On the Origin of Translation

    NASA Astrophysics Data System (ADS)

    Vitas, Marko; Dobovišek, Andrej

    2018-04-01

    The origin of translation is critical for understanding the evolution of life, including the origins of life. The canonical genetic code is one of the most dominant aspects of life on this planet, while the origin of heredity is one of the key evolutionary transitions in living world. Why the translation apparatus evolved is one of the enduring mysteries of molecular biology. Assuming the hypothesis, that during the emergence of life evolution had to first involve autocatalytic systems which only subsequently acquired the capacity of genetic heredity, we propose and discuss possible mechanisms, basic aspects of the emergence and subsequent molecular evolution of translation and ribosomes, as well as enzymes as we know them today. It is possible, in this sense, to view the ribosome as a digital-to-analogue information converter. The proposed mechanism is based on the abilities and tendencies of short RNA and polypeptides to fold and to catalyse biochemical reactions. The proposed mechanism is in concordance with the hypothesis of a possible chemical co-evolution of RNA and proteins in the origin of the genetic code or even more generally at the early evolution of life on Earth. The possible abundance and availability of monomers at prebiotic conditions are considered in the mechanism. The hypothesis that early polypeptides were folding on the RNA scaffold is also considered and mutualism in molecular evolutionary development of RNA and peptides is favoured.

  9. Protein change in plant evolution: tracing one thread connecting molecular and phenotypic diversity

    PubMed Central

    Bartlett, Madelaine E.; Whipple, Clinton J.

    2013-01-01

    Proteins change over the course of evolutionary time. New protein-coding genes and gene families emerge and diversify, ultimately affecting an organism’s phenotype and interactions with its environment. Here we survey the range of structural protein change observed in plants and review the role these changes have had in the evolution of plant form and function. Verified examples tying evolutionary change in protein structure to phenotypic change remain scarce. We will review the existing examples, as well as draw from investigations into domestication, and quantitative trait locus (QTL) cloning studies searching for the molecular underpinnings of natural variation. The evolutionary significance of many cloned QTL has not been assessed, but all the examples identified so far have begun to reveal the extent of protein structural diversity tolerated in natural systems. This molecular (and phenotypic) diversity could come to represent part of natural selection’s source material in the adaptive evolution of novel traits. Protein structure and function can change in many distinct ways, but the changes we identified in studies of natural diversity and protein evolution were predicted to fall primarily into one of six categories: altered active and binding sites; altered protein–protein interactions; altered domain content; altered activity as an activator or repressor; altered protein stability; and hypomorphic and hypermorphic alleles. There was also variability in the evolutionary scale at which particular changes were observed. Some changes were detected at both micro- and macroevolutionary timescales, while others were observed primarily at deep or shallow phylogenetic levels. This variation might be used to determine the trajectory of future investigations in structural molecular evolution. PMID:24124420

  10. Molecular evolution of the CYP2D subfamily in primates: purifying selection on substrate recognition sites without the frequent or long-tract gene conversion.

    PubMed

    Yasukochi, Yoshiki; Satta, Yoko

    2015-03-25

    The human cytochrome P450 (CYP) 2D6 gene is a member of the CYP2D gene subfamily, along with the CYP2D7P and CYP2D8P pseudogenes. Although the CYP2D6 enzyme has been studied extensively because of its clinical importance, the evolution of the CYP2D subfamily has not yet been fully understood. Therefore, the goal of this study was to reveal the evolutionary process of the human drug metabolic system. Here, we investigate molecular evolution of the CYP2D subfamily in primates by comparing 14 CYP2D sequences from humans to New World monkey genomes. Window analysis and statistical tests revealed that entire genomic sequences of paralogous genes were extensively homogenized by gene conversion during molecular evolution of CYP2D genes in primates. A neighbor-joining tree based on genomic sequences at the nonsubstrate recognition sites showed that CYP2D6 and CYP2D8 genes were clustered together due to gene conversion. In contrast, a phylogenetic tree using amino acid sequences at substrate recognition sites did not cluster the CYP2D6 and CYP2D8 genes, suggesting that the functional constraint on substrate specificity is one of the causes for purifying selection at the substrate recognition sites. Our results suggest that the CYP2D gene subfamily in primates has evolved to maintain the regioselectivity for a substrate hydroxylation activity between individual enzymes, even though extensive gene conversion has occurred across CYP2D coding sequences. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  11. From the ultrasonic to the infrared: molecular evolution and the sensory biology of bats

    PubMed Central

    Jones, Gareth; Teeling, Emma C.; Rossiter, Stephen J.

    2013-01-01

    Great advances have been made recently in understanding the genetic basis of the sensory biology of bats. Research has focused on the molecular evolution of candidate sensory genes, genes with known functions [e.g., olfactory receptor (OR) genes] and genes identified from mutations associated with sensory deficits (e.g., blindness and deafness). For example, the FoxP2 gene, underpinning vocal behavior and sensorimotor coordination, has undergone diversification in bats, while several genes associated with audition show parallel amino acid substitutions in unrelated lineages of echolocating bats and, in some cases, in echolocating dolphins, representing a classic case of convergent molecular evolution. Vision genes encoding the photopigments rhodopsin and the long-wave sensitive opsin are functional in bats, while that encoding the short-wave sensitive opsin has lost functionality in rhinolophoid bats using high-duty cycle laryngeal echolocation, suggesting a sensory trade-off between investment in vision and echolocation. In terms of olfaction, bats appear to have a distinctive OR repertoire compared with other mammals, and a gene involved in signal transduction in the vomeronasal system has become non-functional in most bat species. Bitter taste receptors appear to have undergone a “birth-and death” evolution involving extensive gene duplication and loss, unlike genes coding for sweet and umami tastes that show conservation across most lineages but loss in vampire bats. Common vampire bats have also undergone adaptations for thermoperception, via alternative splicing resulting in the evolution of a novel heat-sensitive channel. The future for understanding the molecular basis of sensory biology is promising, with great potential for comparative genomic analyses, studies on gene regulation and expression, exploration of the role of alternative splicing in the generation of proteomic diversity, and linking genetic mechanisms to behavioral consequences. PMID:23755015

  12. Sequence space and the ongoing expansion of the protein universe.

    PubMed

    Povolotskaya, Inna S; Kondrashov, Fyodor A

    2010-06-17

    The need to maintain the structural and functional integrity of an evolving protein severely restricts the repertoire of acceptable amino-acid substitutions. However, it is not known whether these restrictions impose a global limit on how far homologous protein sequences can diverge from each other. Here we explore the limits of protein evolution using sequence divergence data. We formulate a computational approach to study the rate of divergence of distant protein sequences and measure this rate for ancient proteins, those that were present in the last universal common ancestor. We show that ancient proteins are still diverging from each other, indicating an ongoing expansion of the protein sequence universe. The slow rate of this divergence is imposed by the sparseness of functional protein sequences in sequence space and the ruggedness of the protein fitness landscape: approximately 98 per cent of sites cannot accept an amino-acid substitution at any given moment but a vast majority of all sites may eventually be permitted to evolve when other, compensatory, changes occur. Thus, approximately 3.5 x 10(9) yr has not been enough to reach the limit of divergent evolution of proteins, and for most proteins the limit of sequence similarity imposed by common function may not exceed that of random sequences.

  13. Proceedings of the Astrobiology Science Conference 2010. Evolution and Life: Surviving Catastrophes and Extremes on Earth and Beyond

    NASA Technical Reports Server (NTRS)

    2010-01-01

    The Program of the 2010 Astrobiology Science Conference: Evolution and Life: Surviving Catastrophes and Extremes on Earth and Beyond, included sessions on: 50 Years of Exobiology and Astrobiology: Greatest Hits; Extraterrestrial Molecular Evolution and Pre-Biological Chemistry: From the Interstellar Medium to the Solar System I; Human Exploration, Astronaut Health; Diversity in Astrobiology Research and Education; Titan: Past, Present, and Future; Energy Flow in Microbial Ecosystems; Extraterrestrial Molecular Evolution and Prebiological Chemistry: From the Interstellar Medium to the Solar System II; Astrobiology in Orbit; Astrobiology and Interdisciplinary Communication; Science from Rio Tinto: An Acidic Environment; Can We Rule Out Spontaneous Generation of RNA as the Key Step in the Origin of Life?; How Hellish Was the Hadean Earth?; Results from ASTEP and Other Astrobiology Field Campaigns I; Prebiotic Evolution: From Chemistry to Life I; Adaptation of Life in Hostile Space Environments; Extrasolar Terrestrial Planets I: Formation and Composition; Collaborative Tools and Technology for Astrobiology; Results from ASTEP and Other Astrobiology Field Campaigns II; Prebiotic Evolution: From Chemistry to Life II; Survival, Growth, and Evolution of Microrganisms in Model Extraterrestrial Environments; Extrasolar Terrestrial Planets II: Habitability and Life; Planetary Science Decadal Survey Update; Astrobiology Research Funding; Bioessential Elements Through Space and Time I; State of the Art in Life Detection; Terrestrial Evolution: Implications for the Past, Present, and Future of Life on Earth; Psychrophiles and Polar Environments; Life in Volcanic Environments: On Earth and Beyond; Geochronology and Astrobiology On and Off the Earth; Bioessential Elements Through Space and Time II; Origins and Evolution of Genetic Systems; Evolution of Advanced Life; Water-rich Asteroids and Moons: Composition and Astrobiological Potential; Impact Events and Evolution; A Warm, Wet Mars?; Titan Versus Europa - Potential for Astrobiology; Habitability Potential of Mars; Biosignatures: Tools and Development I; Origins of Molecular Asymmetry, Homochirality, and Life Detection; Deserts and Evaporite Basins and Associated Microbialite Systems; Ancient Life and Synthetic Biology: Crossroad of the Past and Future; Biosignatures: Tools and Development II; Free Oxygen: Proxies, Causes, and Consequences; Life in Modern Microbialite Systems - Function and Adaptation; Hydrothermal Systems and Organosynthesis Processes: Origin and Evolution of Life; Where Should We Go on Mars to Seek Signs of Life?; Search for Intelligent Life I. Innovative SETI Observing Programs and Future Directions; Integrating Astrobiology Research Across and Beyond the Community; Education in Astrobiology in K-12; Search for Intelligent Life II. Global Engagement and Interstellar Message Construction; Poster sessions included: Extraterrestrial Molecular Evolution and Pre-Biological Chemistry; Prebiotic Evolution: From Chemistry to Life; RNA World; Terrestrial Evolution: Implications for the Past, Present, and Future of Life on Earth; Hydrothermal Systems and Organosynthesis Processes: Origin and Evolution of Life; Virology and Astrobiology; Horizontal Genetic Transfer and Properties of Ancestral Organisms; Life in Volcanic Environments: On Earth and Beyond; Impact Events and Evolution; Evolution of Advanced Life; Evolution of Intelligent Life; Education in Astrobiology in K-12; Origins of Molecular Asymmetry, Homochirality, and Life Detection; Astrobiology and Interdisciplinary Communication; Diversity in Astrobiology Research and Education; Integrating Astrobiology Research Across and Beyond the Community; Policy and Societal Issues: Dealing with Potential Bumps in the Astrobiology Road Ahead; Results from ASTEP and Other Astrobiology Field Campaigns; Energy Flow in Microbial Ecosystems; Psychrophiles and Polar Environments; Deserts and Evaporite Basins and Associated Microbialite stems; Life in Modern Microbialite Systems - Function and Adaptation; Free Oxygen: Proxies, Causes, and Consequences; Bioessential Elements Through Space and Time; Water-rich Asteroids and Moons: Composition and Astrobiological Potential; Biosignatures: Tools and Developments; Robotics and Instrumentation for Astrobiology; State of the Art in Life Detection; Astrobiology in Orbit; Survival, Growth, and Evolution of Microrganisms in Model Extraterrestrial Evolution; Search for Intelligent Life; Habitability Potential of Mars; How and Where Should We Seek Signs of Life on Mars?; Titan: Past, Present, and Future; Extrasolar Terrestrial Planets: Formation, Composition, Diversity, Habitability and Life; Human Exploration, Astronaut Health; Science from Rio Tinto: An Acidic Environment and Adaptation of Life in Hostile Space Environments;

  14. Chemical Evolution of Protostellar Matter

    NASA Technical Reports Server (NTRS)

    Langer, William D.; vanDishoeck, Ewine F.; Bergin, Edwin A.; Blake, Geoffrey A.; Tielens, Alexander G. G. M.; Velusamy, Thangasamy; Whittet, Douglas C. B.

    2000-01-01

    We review the chemical processes that are important in the evolution from a molecular cloud core to a protostellar disk. These cover both gas phase and gas grain interactions. The current observational and theoretical state of this field are discussed.

  15. The clinical study of the optimalization of surgical treatment and the traditional Chinese medicine intervention on palmar hyperhidrosis.

    PubMed

    Yang, Yong; Yan, Zhikun; Fu, Xiaoqing; Dong, Liwen; Xu, Linhai; Wang, Jun; Cheng, Genmiao

    2014-11-01

    To analyze the efficacy of different surgical methods in treating palmar hyperhidrosis and the compensatory hyperhidrosis after surgery and to observe the efficacy of "Energy-boosting and Yin-nourishing anti-perspirant formula" on postsurgical hyperhidrosis patients. Two-hundred patients were randomly assigned to groups A (Chinese and Western medicine, T4 transection plus "Energy-boosting and Yin-nourishing anti-perspirant formula") and B (Western medicine, T4 transection). The surgical efficiency, recurrence rate, compensatory hyperhidrosis, and the long-term life quality were compared. Another 100 cases (group C, T2 transection) were analyzed as a control group. After surgery, the palmar hyperhidrosis and armpit sweating were relieved in all the three group patients and in 34 % of patients combined with plantar hyperhidrosis, the symptoms were relieved. Transient palmar hyperhidrosis was found in three cases at day 2 to day 5 postoperatively. One case of Horner's syndrome and one case recurrence were found in group C patients. The compensatory sweating of various degrees occurred in all the three groups. There were 25, 24, and 43 cases in groups A, B, and C, respectively. There is a significant difference between groups C, A, and B. The compensatory sweating in 13 cases of group A and four cases of group B had different degrees of improvement in the follow-up 6 months after surgery. There is a significant difference. Thoracoscopic bilateral T4 sympathetic chain and the Kuntz resection are the optimized surgical treatments for the palmar hyperhidrosis. "Energy-boosting and Yin-nourishing anti-perspirant formula" is effective in treating the postoperative compensatory sweating.

  16. Correlates of individual differences in compensatory nicotine self-administration in rats following a decrease in nicotine unit dose

    PubMed Central

    Harris, Andrew C.; Pentel, Paul R.; LeSage, Mark G.

    2013-01-01

    Rationale The ability of tobacco harm reduction strategies to produce significant reductions in toxin exposure is limited by compensatory increases in smoking behavior. Characterizing factors contributing to the marked individual variability in compensation may be useful for understanding this phenomenon and assessing the feasibility of harm reduction interventions. Objective To use an animal model of human compensatory smoking that involves a decrease in unit dose supporting nicotine self-administration (NSA) to examine potential contributors to individual differences in compensation. Methods Rats were trained for NSA during daily 23 hr sessions at a unit dose of 0.06 mg/kg/inf until responding was stable. The unit dose was then reduced to 0.03 mg/kg/inf for at least 10 sessions. Following reacquisition of NSA at the training dose and extinction, single-dose nicotine pharmacokinetic parameters were determined. Results Decreases in nicotine intake following dose reduction were proportionally less than the decrease in unit dose, indicating partial compensation. Compensatory increases in infusion rates were observed across the course of the 23 hr sessions. The magnitude of compensation differed considerably between rats. Rats exhibiting the highest baseline infusion rates exhibited the lowest levels of compensation. Nicotine pharmacokinetic parameters were not significantly correlated with compensation. Infusion rates immediately returned to pre-reduction levels when baseline conditions were restored. Conclusions These findings provide initial insights into correlates of individual differences in compensation following a reduction in nicotine unit dose. The present assay may be useful for characterizing mechanisms and potential consequences of the marked individual differences in compensatory smoking observed in humans. PMID:19475400

  17. A Prospective Cohort Study on Quality of Life after Endoscopic Thoracic Sympathectomy for Primary Hyperhidrosis.

    PubMed

    Dharmaraj, B; Kosai, N R; Gendeh, H; Ramzisham, A R; Das, S

    2016-01-01

    Hyperhidrosis is an excessive sweating disorder affecting quality of life. Endoscopic thoracic sympathectomy (ETS), introduced by Kux in 1951, is currently the gold standard surgical treatment for primary hyperhidrosis. 75% of patients with primary hyperhidrosis have seen improvement in quality of life within 30 days after surgery. Compensatory hyperhidrosis and pneumothorax (up to 75%) have been reported in patients after surgery. This study evaluates the functional status, self- esteem, compensatory hyperhidrosis and quality of life among patient with primary hyperhidrosis before and after undergoing ETS. Fifty (n=50) patients between the ages 18 to 30, with primary hyperhidrosis were recruited. Patients answered the quality of life questionnaire and Rosenberg self-esteem questionnaire prior to surgery and 30 days post surgery on follow up. Any post-operative complications were documented. Telephone interviews were held for patients who were unable to attend the clinics for follow-up. Forty six patients (92%) had symptomatic relieve within 30 days of surgery. The incidence of compensatory sweating was 78% (39 patients), with 6 patients developing severe hyperhidrosis. Two patients who did not experience symptomatic relieve, developed compensatory hyperhidrosis. Pneumothorax was documented in 8 patients (16%), with 6 patients requiring chest tubes. Significant improvement in quality of life and self-esteem was seen among patients after surgery. ETS has shown to significantly improve the quality of life and self-esteem of patients with primary hyperhidrosis within 30 days of surgery. However, the rate of compensatory hyperhidrosis still remains high (78%) which requires a long term evaluation.

  18. Molecular Evolution of Clustered MIC-3 (Meloidogyne Induced Cotton -3) Multigene Family of Gossypium Species

    USDA-ARS?s Scientific Manuscript database

    Uniqueness, content, localization, and defense-related features of the root-knot nematode resistance-associated MIC-3 multigene cluster in the genus Gossypium are all of interest for molecular evolutionary studies of duplicate genes in allopolyploids. Here we report molecular evolutionary rates of t...

  19. [Mobile genetic elements in plant sex evolution].

    PubMed

    Gerashchenkov, G A; Rozhnova, N A

    2010-11-01

    The most significant theories of the appearance and maintenance of sex are presented. However, in the overwhelming majority of existing theories, the problem of sex, which is the central problem of evolutionary biology, is considered primarily through the prism of reproductive features of living organisms, whereas the issue of molecular driving forces of sexual reproduction id restricted to the possible role of mobile genetic elements (MGEs) in the appearance of sexual reproduction. The structural and functional significance of MGEs in the genomic organization of plants is illustrated. It is shown that MGEs could act as important molecular drivers of sex evolution in plants. The involvement of MGEs in the formation of sex chromosomes and possible participation in seeds-without-sex reproduction (apomixis) is discussed. Thus, the hypothesis on the active MGE participation in sex evolution is in good agreement with the modern views on pathways and directions of sex evolution in plants.

  20. Evolutionary anthropology and genes: investigating the genetics of human evolution from excavated skeletal remains.

    PubMed

    Anastasiou, Evilena; Mitchell, Piers D

    2013-10-01

    The development of molecular tools for the extraction, analysis and interpretation of DNA from the remains of ancient organisms (paleogenetics) has revolutionised a range of disciplines as diverse as the fields of human evolution, bioarchaeology, epidemiology, microbiology, taxonomy and population genetics. The paper draws attention to some of the challenges associated with the extraction and interpretation of ancient DNA from archaeological material, and then reviews the influence of paleogenetics on the field of human evolution. It discusses the main contributions of molecular studies to reconstructing the evolutionary and phylogenetic relationships between extinct hominins (human ancestors) and anatomically modern humans. It also explores the evidence for evolutionary changes in the genetic structure of anatomically modern humans in recent millennia. This breadth of research has led to discoveries that would never have been possible using traditional approaches to human evolution. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Convergent evolution of the genomes of marine mammals

    USGS Publications Warehouse

    Foote, Andrew D.; Liu, Yue; Thomas, Gregg W.C.; Vinař, Tomáš; Alföldi, Jessica; Deng, Jixin; Dugan, Shannon; van Elk, Cornelis E.; Hunter, Margaret; Joshi, Vandita; Khan, Ziad; Kovar, Christie; Lee, Sandra L.; Lindblad-Toh, Kerstin; Mancia, Annalaura; Nielsen, Rasmus; Qin, Xiang; Qu, Jiaxin; Raney, Brian J.; Vijay, Nagarjun; Wolf, Jochen B. W.; Hahn, Matthew W.; Muzny, Donna M.; Worley, Kim C.; Gilbert, M. Thomas P.; Gibbs, Richard A.

    2015-01-01

    Marine mammals from different mammalian orders share several phenotypic traits adapted to the aquatic environment and therefore represent a classic example of convergent evolution. To investigate convergent evolution at the genomic level, we sequenced and performed de novo assembly of the genomes of three species of marine mammals (the killer whale, walrus and manatee) from three mammalian orders that share independently evolved phenotypic adaptations to a marine existence. Our comparative genomic analyses found that convergent amino acid substitutions were widespread throughout the genome and that a subset of these substitutions were in genes evolving under positive selection and putatively associated with a marine phenotype. However, we found higher levels of convergent amino acid substitutions in a control set of terrestrial sister taxa to the marine mammals. Our results suggest that, whereas convergent molecular evolution is relatively common, adaptive molecular convergence linked to phenotypic convergence is comparatively rare.

  2. Convergent evolution of the genomes of marine mammals

    PubMed Central

    Foote, Andrew D.; Liu, Yue; Thomas, Gregg W.C.; Vinař, Tomáš; Alföldi, Jessica; Deng, Jixin; Dugan, Shannon; van Elk, Cornelis E.; Hunter, Margaret E.; Joshi, Vandita; Khan, Ziad; Kovar, Christie; Lee, Sandra L.; Lindblad-Toh, Kerstin; Mancia, Annalaura; Nielsen, Rasmus; Qin, Xiang; Qu, Jiaxin; Raney, Brian J.; Vijay, Nagarjun; Wolf, Jochen B. W.; Hahn, Matthew W.; Muzny, Donna M.; Worley, Kim C.; Gilbert, M. Thomas P.; Gibbs, Richard A.

    2015-01-01

    Marine mammals from different mammalian orders share several phenotypic traits adapted to the aquatic environment and are therefore a classic example of convergent evolution. To investigate convergent evolution at the genomic level, we sequenced and de novo assembled the genomes of three species of marine mammals (the killer whale, walrus and manatee) from three mammalian orders that share independently evolved phenotypic adaptations to a marine existence. Our comparative genomic analyses found that convergent amino acid substitutions were widespread throughout the genome, and that a subset were in genes evolving under positive selection and putatively associated with a marine phenotype. However, we found higher levels of convergent amino acid substitutions in a control set of terrestrial sister taxa to the marine mammals. Our results suggest that while convergent molecular evolution is relatively common, adaptive molecular convergence linked to phenotypic convergence is comparatively rare. PMID:25621460

  3. Comparison of Mitochondrial Reactive Oxygen Species Production of Ectothermic and Endothermic Fish Muscle

    PubMed Central

    Wiens, Lilian; Banh, Sheena; Sotiri, Emianka; Jastroch, Martin; Block, Barbara A.; Brand, Martin D.; Treberg, Jason R.

    2017-01-01

    Recently we demonstrated that the capacity of isolated muscle mitochondria to produce reactive oxygen species, measured as H2O2 efflux, is temperature-sensitive in isolated muscle mitochondria of ectothermic fish and the rat, a representative endothermic mammal. However, at physiological temperatures (15° and 37°C for the fish and rat, respectively), the fraction of total mitochondrial electron flux that generated H2O2, the fractional electron leak (FEL), was far lower in the rat than in fish. Those results suggested that the elevated body temperatures associated with endothermy may lead to a compensatory decrease in mitochondrial ROS production relative to respiratory capacity. To test this hypothesis we compare slow twitch (red) muscle mitochondria from the endothermic Pacific bluefin tuna (Thunnus orientalis) with mitochondria from three ectothermic fishes [rainbow trout (Oncorhynchus mykiss), common carp (Cyprinus carpio), and the lake sturgeon (Acipenser fulvescens)] and the rat. At a common assay temperature (25°C) rates of mitochondrial respiration and H2O2 efflux were similar in tuna and the other fishes. The thermal sensitivity of fish mitochondria was similar irrespective of ectothermy or endothermy. Comparing tuna to the rat at a common temperature, respiration rates were similar, or lower depending on mitochondrial substrates. FEL was not different across fish species at a common assay temperature (25°C) but was markedly higher in fishes than in rat. Overall, endothermy and warming of Pacific Bluefin tuna red muscle may increase the potential for ROS production by muscle mitochondria but the evolution of endothermy in this species is not necessarily associated with a compensatory reduction of ROS production relative to the respiratory capacity of mitochondria. PMID:28966595

  4. Effects of different dietary conditions on the expression of trypsin- and chymotrypsin-like protease genes in the digestive system of the migratory locust, Locusta migratoria.

    PubMed

    Spit, Jornt; Zels, Sven; Dillen, Senne; Holtof, Michiel; Wynant, Niels; Vanden Broeck, Jozef

    2014-05-01

    While technological advancements have recently led to a steep increase in genomic and transcriptomic data, and large numbers of protease sequences are being discovered in diverse insect species, little information is available about the expression of digestive enzymes in Orthoptera. Here we describe the identification of Locusta migratoria serine protease transcripts (cDNAs) involved in digestion, which might serve as possible targets for pest control management. A total of 5 putative trypsin and 15 putative chymotrypsin gene sequences were characterized. Phylogenetic analysis revealed that these are distributed among 3 evolutionary conserved clusters. In addition, we have determined the relative gene expression levels of representative members in the gut under different feeding conditions. This study demonstrated that the transcript levels for all measured serine proteases were strongly reduced after starvation. On the other hand, larvae of L. migratoria displayed compensatory effects to the presence of Soybean Bowman Birk (SBBI) and Soybean Trypsin (SBTI) inhibitors in their diet by differential upregulation of multiple proteases. A rapid initial upregulation was observed for all tested serine protease transcripts, while only for members belonging to class I, the transcript levels remained elevated after prolonged exposure. In full agreement with these results, we also observed an increase in proteolytic activity in midgut secretions of locusts that were accustomed to the presence of protease inhibitors in their diet, while no change in sensitivity to these inhibitors was observed. Taken together, this paper is the first comprehensive study on dietary dependent transcript levels of proteolytic enzymes in Orthoptera. Our data suggest that compensatory response mechanisms to protease inhibitor ingestion may have appeared early in insect evolution. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Testing the molecular clock using mechanistic models of fossil preservation and molecular evolution

    PubMed Central

    2017-01-01

    Molecular sequence data provide information about relative times only, and fossil-based age constraints are the ultimate source of information about absolute times in molecular clock dating analyses. Thus, fossil calibrations are critical to molecular clock dating, but competing methods are difficult to evaluate empirically because the true evolutionary time scale is never known. Here, we combine mechanistic models of fossil preservation and sequence evolution in simulations to evaluate different approaches to constructing fossil calibrations and their impact on Bayesian molecular clock dating, and the relative impact of fossil versus molecular sampling. We show that divergence time estimation is impacted by the model of fossil preservation, sampling intensity and tree shape. The addition of sequence data may improve molecular clock estimates, but accuracy and precision is dominated by the quality of the fossil calibrations. Posterior means and medians are poor representatives of true divergence times; posterior intervals provide a much more accurate estimate of divergence times, though they may be wide and often do not have high coverage probability. Our results highlight the importance of increased fossil sampling and improved statistical approaches to generating calibrations, which should incorporate the non-uniform nature of ecological and temporal fossil species distributions. PMID:28637852

  6. Structural molecular components of septate junctions in cnidarians point to the origin of epithelial junctions in eukaryotes.

    PubMed

    Ganot, Philippe; Zoccola, Didier; Tambutté, Eric; Voolstra, Christian R; Aranda, Manuel; Allemand, Denis; Tambutté, Sylvie

    2015-01-01

    Septate junctions (SJs) insure barrier properties and control paracellular diffusion of solutes across epithelia in invertebrates. However, the origin and evolution of their molecular constituents in Metazoa have not been firmly established. Here, we investigated the genomes of early branching metazoan representatives to reconstruct the phylogeny of the molecular components of SJs. Although Claudins and SJ cytoplasmic adaptor components appeared successively throughout metazoan evolution, the structural components of SJs arose at the time of Placozoa/Cnidaria/Bilateria radiation. We also show that in the scleractinian coral Stylophora pistillata, the structural SJ component Neurexin IV colocalizes with the cortical actin network at the apical border of the cells, at the place of SJs. We propose a model for SJ components in Cnidaria. Moreover, our study reveals an unanticipated diversity of SJ structural component variants in cnidarians. This diversity correlates with gene-specific expression in calcifying and noncalcifying tissues, suggesting specific paracellular pathways across the cell layers of these diploblastic animals. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Understanding the reaction of nuclear graphite with molecular oxygen: Kinetics, transport, and structural evolution

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kane, Joshua J.; Contescu, Cristian I.; Smith, Rebecca E.

    A thorough understanding of oxidation is important when considering the health and integrity of graphite components in graphite reactors. For the next generation of graphite reactors, HTGRs specifically, an unlikely air ingress has been deemed significant enough to have made its way into the licensing applications of many international licensing bodies. While a substantial body of literature exists on nuclear graphite oxidation in the presence of molecular oxygen and significant efforts have been made to characterize oxidation kinetics of various grades, the value of existing information is somewhat limited. Often, multiple competing processes, including reaction kinetics, mass transfer, and microstructuralmore » evolution, are lumped together into a single rate expression that limits the ability to translate this information to different conditions. This article reviews the reaction of graphite with molecular oxygen in terms of the reaction kinetics, gas transport, and microstructural evolution of graphite. It also presents the foundations of a model for the graphite-molecular oxygen reaction system that is kinetically independent of graphite grade, and is capable of describing both the bulk and local oxidation rates under a wide range of conditions applicable to air-ingress.« less

  8. Understanding the reaction of nuclear graphite with molecular oxygen: Kinetics, transport, and structural evolution

    DOE PAGES

    Kane, Joshua J.; Contescu, Cristian I.; Smith, Rebecca E.; ...

    2017-06-08

    A thorough understanding of oxidation is important when considering the health and integrity of graphite components in graphite reactors. For the next generation of graphite reactors, HTGRs specifically, an unlikely air ingress has been deemed significant enough to have made its way into the licensing applications of many international licensing bodies. While a substantial body of literature exists on nuclear graphite oxidation in the presence of molecular oxygen and significant efforts have been made to characterize oxidation kinetics of various grades, the value of existing information is somewhat limited. Often, multiple competing processes, including reaction kinetics, mass transfer, and microstructuralmore » evolution, are lumped together into a single rate expression that limits the ability to translate this information to different conditions. This article reviews the reaction of graphite with molecular oxygen in terms of the reaction kinetics, gas transport, and microstructural evolution of graphite. It also presents the foundations of a model for the graphite-molecular oxygen reaction system that is kinetically independent of graphite grade, and is capable of describing both the bulk and local oxidation rates under a wide range of conditions applicable to air-ingress.« less

  9. Detection of biological threats. A challenge for directed molecular evolution.

    PubMed

    Petrenko, Valery A; Sorokulova, Iryna B

    2004-08-01

    The probe technique originated from early attempts of Anton van Leeuwenhoek to contrast microorganisms under the microscope using plant juices, successful staining of tubercle bacilli with synthetic dyes by Paul Ehrlich and discovery of a stain for differentiation of gram-positive and gram-negative bacteria by Hans Christian Gram. The technique relies on the principle that pathogens have unique structural features, which can be recognized by specifically labeled organic molecules. A hundred years of extensive screening efforts led to discovery of a limited assortment of organic probes that are used for identification and differentiation of bacteria. A new challenge--continuous monitoring of biological threats--requires long lasting molecular probes capable of tight specific binding of pathogens in unfavorable conditions. To respond to the challenge, probe technology is being revolutionized by utilizing methods of combinatorial chemistry, phage display and directed molecular evolution. This review describes how molecular evolution methods are applied for development of peptide, antibody and phage probes, and summarizes the author's own data on development of landscape phage probes against Salmonella typhimurium. The performance of the probes in detection of Salmonella is illustrated by a precipitation test, enzyme-linked immunosorbent assay (ELISA), fluorescence-activated cell sorting (FACS) and fluorescent, optical and electron microscopy.

  10. Reconciling extreme branch length differences: decoupling time and rate through the evolutionary history of filmy ferns.

    PubMed

    Schuettpelz, Eric; Pryer, Kathleen M

    2006-06-01

    The rate of molecular evolution is not constant across the Tree of Life. Characterizing rate discrepancies and evaluating the relative roles of time and rate along branches through the past are both critical to a full understanding of evolutionary history. In this study, we explore the interactions of time and rate in filmy ferns (Hymenophyllaceae), a lineage with extreme branch length differences between the two major clades. We test for the presence of significant rate discrepancies within and between these clades, and we separate time and rate across the filmy fern phylogeny to simultaneously yield an evolutionary time scale of filmy fern diversification and reconstructions of ancestral rates of molecular evolution. Our results indicate that the branch length disparity observed between the major lineages of filmy ferns is indeed due to a significant difference in molecular evolutionary rate. The estimation of divergence times reveals that the timing of crown group diversification was not concurrent for the two lineages, and the reconstruction of ancestral rates of molecular evolution points to a substantial rate deceleration in one of the clades. Further analysis suggests that this may be due to a genome-wide deceleration in the rate of nucleotide substitution.

  11. Compensatory value of an urban forest: an application of the tree-value formula

    Treesearch

    David J. Nowak

    1993-01-01

    Understanding the value of an urban forest can give decisionmakers a better foundation for urban tree management. According to the tree-valuation formula of the Council of Tree and Landscape Appraisers, the estimated compensatory value of the urban forest in Oakland, California, (21% tree cover) is $385.7 million, with residential trees accounting for 58.6% of the...

  12. Improving Public Speaking Skills in the Seventh Grade Compensatory Education Student through Enhanced Instruction and Opportunity for Practice.

    ERIC Educational Resources Information Center

    Wilson, Nan Kelly

    This practicum addressed the problem of seventh grade compensatory education students' not having adequate instruction, opportunity, or experience to prepare for success in any level of eighth grade English. Overall goals for the practicum were to give instruction in public speaking, to provide opportunities for students to engage in public…

  13. Compensatory Prekindergarteners' I.Q. Gain Correlated with Third Grade Reading Achievement.

    ERIC Educational Resources Information Center

    Archer, Philip D.; Sewall, Michael B.

    The purpose of this study was to investigate the correlation between gain on the Stanford-Binet Intelligence Test (S-B) in compensatory prekindergarten programs, and scores on the New York State Pupil Evaluation Program (PEP), Reading Section, over three years later. Four hundred and five subjects showed a correlation of 0.42 for the pre-post S-B…

  14. Social Pedagogy and Liberal Egalitarian Compensatory Programs: The Case of Head Start

    ERIC Educational Resources Information Center

    Counsell, Shelly Lynn; Boody, Robert M.

    2013-01-01

    Using Head Start as an example of a compensatory social program based on a liberal egalitarian view of justice, this paper shows how all such programs are fundamentally flawed. In spite of any good intentions, by creating a discourse of deficiency and attempting amelioration through segregation this approach contains the seeds of its own failure.…

  15. Equivalency of the DINA Model and a Constrained General Diagnostic Model. Research Report. ETS RR-11-37

    ERIC Educational Resources Information Center

    von Davier, Matthias

    2011-01-01

    This report shows that the deterministic-input noisy-AND (DINA) model is a special case of more general compensatory diagnostic models by means of a reparameterization of the skill space and the design (Q-) matrix of item by skills associations. This reparameterization produces a compensatory model that is equivalent to the (conjunctive) DINA…

  16. STEPS TOWARD COMPENSATORY EDUCATION IN THE CHICAGO PUBLIC SCHOOLS. HIGH SCHOOL DISTRICTS. REPORT OF AN EVALUATIVE STUDY.

    ERIC Educational Resources Information Center

    CITIZENS SCHOOLS COMMITTEE OF CHICAGO

    THE CITIZENS COMMITTEE OFFERS SUGGESTIONS FOR COMPENSATORY EDUCATION TO MEET THE NEEDS OF ALL CHILDREN LIVING IN AREAS OF HIGH TRANSIENCY WHO HAVE EXPERIENCED A MEAGER EDUCATIONAL BACKGROUND. THE SUGGESTIONS ARE--THAT CLASS SIZE BE LIMITED TO 25 STUDENTS. THAT THE LENGTH OF SCHOOL IN "DIFFICULT" AREAS BE LENGTHENED, AND THAT THE SALARY…

  17. Do Children Who Acquire Word Reading without Explicit Phonics Employ Compensatory Learning? Issues of Phonological Recoding, Lexical Orthography, and Fluency

    ERIC Educational Resources Information Center

    Thompson, G. Brian; McKay, Michael F.; Fletcher-Flinn, Claire M.; Connelly, Vincent; Kaa, Richard T.; Ewing, Jason

    2008-01-01

    Two studies were conducted across three countries to examine samples of beginning readers without systematic explicit phonics who had reached the same level of word reading accuracy as comparison samples with high and moderate explicit phonics. Had they employed any compensatory learning to reach that level? Four hypotheses of compensatory…

  18. On compensatory strategies and computational models: the case of pure alexia.

    PubMed

    Shallice, Tim

    2014-01-01

    The article is concerned with inferences from the behaviour of neurological patients to models of normal function. It takes the letter-by-letter reading strategy common in pure alexic patients as an example of the methodological problems involved in making such inferences that compensatory strategies produce. The evidence is discussed on the possible use of three ways the letter-by-letter reading process might operate: "reversed spelling"; the use of the phonological input buffer as a temporary holding store during word building; and the use of serial input to the visual word-form system entirely within the visual-orthographic domain such as in the model of Plaut [1999. A connectionist approach to word reading and acquired dyslexia: Extension to sequential processing. Cognitive Science, 23, 543-568]. The compensatory strategy used by, at least, one pure alexic patient does not fit with the third of these possibilities. On the more general question, it is argued that even if compensatory strategies are being used, the behaviour of neurological patients can be useful for the development and assessment of first-generation information-processing models of normal function, but they are not likely to be useful for the development and assessment of second-generation computational models.

  19. Assessing state efforts to meet baby boomers' long-term care needs: a case study in compensatory federalism.

    PubMed

    Pandey, Sanjay K

    2002-01-01

    The role of the state government and the character of federal-state relations in social policy have evolved considerably. Frank Thompson uses the phrase compensatory federalism to describe increased activity by state governments to make up for a diminished federal role. For compensatory federalism to work, it is essential for states to take leadership roles in key policy areas. Few studies examine whether states have risen to the challenge of compensatory federalism in social policy. This paper examines an emerging issue of great significance in social policy-challenges involved in meeting future long-term care needs for the baby boomer generation. The paper provides an in-depth case study of attempts by Maryland to meet the challenges of financing long-term care needs for the baby boomer generation. The detailed description of the agenda-setting and problem-structuring process in Maryland is followed by an analysis that uses three different frameworks to assess the policy development processes. These models are rooted in a bureaucratic politics perspective, an agenda-setting perspective and an interest group politics perspective. The paper concludes with a discussion of the limitations and possibilities of state leadership in the social policy sphere.

  20. Consequences of biodiversity loss diverge from expectation due to post-extinction compensatory responses

    NASA Astrophysics Data System (ADS)

    Thomsen, Matthias S.; Garcia, Clement; Bolam, Stefan G.; Parker, Ruth; Godbold, Jasmin A.; Solan, Martin

    2017-03-01

    Consensus has been reached that global biodiversity loss impairs ecosystem functioning and the sustainability of services beneficial to humanity. However, the ecosystem consequences of extinction in natural communities are moderated by compensatory species dynamics, yet these processes are rarely accounted for in impact assessments and seldom considered in conservation programmes. Here, we use marine invertebrate communities to parameterise numerical models of sediment bioturbation - a key mediator of biogeochemical cycling - to determine whether post-extinction compensatory mechanisms alter biodiversity-ecosystem function relations following non-random extinctions. We find that compensatory dynamics lead to trajectories of sediment mixing that diverge from those without compensation, and that the form, magnitude and variance of each probabilistic distribution is highly influenced by the type of compensation and the functional composition of surviving species. Our findings indicate that the generalized biodiversity-function relation curve, as derived from multiple empirical investigations of random species loss, is unlikely to yield representative predictions for ecosystem properties in natural systems because the influence of post-extinction community dynamics are under-represented. Recognition of this problem is fundamental to management and conservation efforts, and will be necessary to ensure future plans and adaptation strategies minimize the adverse impacts of the biodiversity crisis.

  1. The evolution of vertebrate Toll-like receptors

    USGS Publications Warehouse

    Roach, J.C.; Glusman, G.; Rowen, L.; Kaur, A.; Purcell, M.K.; Smith, K.D.; Hood, L.E.; Aderem, A.

    2005-01-01

    The complete sequences of Takifugu Toll-like receptor (TLR) loci and gene predictions from many draft genomes enable comprehensive molecular phylogenetic analysis. Strong selective pressure for recognition of and response to pathogen-associated molecular patterns has maintained a largely unchanging TLR recognition in all vertebrates. There are six major families of vertebrate TLRs. This repertoire is distinct from that of invertebrates. TLRs within a family recognize a general class of pathogen-associated molecular patterns. Most vertebrates have exactly one gene ortholog for each TLR family. The family including TLR1 has more species-specific adaptations than other families. A major family including TLR11 is represented in humans only by a pseudogene. Coincidental evolution plays a minor role in TLR evolution. The sequencing phase of this study produced finished genomic sequences for the 12 Takifugu rubripes TLRs. In addition, we have produced > 70 gene models, including sequences from the opossum, chicken, frog, dog, sea urchin, and sea squirt. ?? 2005 by The National Academy of Sciences of the USA.

  2. Evolution of an ancient protein function involved in organized multicellularity in animals

    PubMed Central

    Anderson, Douglas P; Whitney, Dustin S; Hanson-Smith, Victor; Woznica, Arielle; Campodonico-Burnett, William; Volkman, Brian F; King, Nicole; Thornton, Joseph W; Prehoda, Kenneth E

    2016-01-01

    To form and maintain organized tissues, multicellular organisms orient their mitotic spindles relative to neighboring cells. A molecular complex scaffolded by the GK protein-interaction domain (GKPID) mediates spindle orientation in diverse animal taxa by linking microtubule motor proteins to a marker protein on the cell cortex localized by external cues. Here we illuminate how this complex evolved and commandeered control of spindle orientation from a more ancient mechanism. The complex was assembled through a series of molecular exploitation events, one of which – the evolution of GKPID’s capacity to bind the cortical marker protein – can be recapitulated by reintroducing a single historical substitution into the reconstructed ancestral GKPID. This change revealed and repurposed an ancient molecular surface that previously had a radically different function. We show how the physical simplicity of this binding interface enabled the evolution of a new protein function now essential to the biological complexity of many animals. DOI: http://dx.doi.org/10.7554/eLife.10147.001 PMID:26740169

  3. Negative correlation between rates of molecular evolution and flowering cycles in temperate woody bamboos revealed by plastid phylogenomics.

    PubMed

    Ma, Peng-Fei; Vorontsova, Maria S; Nanjarisoa, Olinirina Prisca; Razanatsoa, Jacqueline; Guo, Zhen-Hua; Haevermans, Thomas; Li, De-Zhu

    2017-12-21

    Heterogeneous rates of molecular evolution are universal across the tree of life, posing challenges for phylogenetic inference. The temperate woody bamboos (tribe Arundinarieae, Poaceae) are noted for their extremely slow molecular evolutionary rates, supposedly caused by their mysterious monocarpic reproduction. However, the correlation between substitution rates and flowering cycles has not been formally tested. Here we present 15 newly sequenced plastid genomes of temperate woody bamboos, including the first genomes ever sequenced from Madagascar representatives. A data matrix of 46 plastid genomes representing all 12 lineages of Arundinarieae was assembled for phylogenetic and molecular evolutionary analyses. We conducted phylogenetic analyses using different sequences (e.g., coding and noncoding) combined with different data partitioning schemes, revealing conflicting relationships involving internodes among several lineages. A great difference in branch lengths were observed among the major lineages, and topological inconsistency could be attributed to long-branch attraction (LBA). Using clock model-fitting by maximum likelihood and Bayesian approaches, we furthermore demonstrated extensive rate variation among these major lineages. Rate accelerations mainly occurred for the isolated lineages with limited species diversification, totaling 11 rate shifts during the tribe's evolution. Using linear regression analysis, we found a negative correlation between rates of molecular evolution and flowering cycles for Arundinarieae, notwithstanding that the correlation maybe insignificant when taking the phylogenetic structure into account. Using the temperate woody bamboos as an example, we found further evidence that rate heterogeneity is universal in plants, suggesting that this will pose a challenge for phylogenetic reconstruction of bamboos. The bamboos with longer flowering cycles tend to evolve more slowly than those with shorter flowering cycles, in accordance with a putative generation time effect.

  4. A review of the evolution of viviparity in squamate reptiles: the past, present and future role of molecular biology and genomics.

    PubMed

    Murphy, Bridget F; Thompson, Michael B

    2011-07-01

    Squamate reptiles (lizards and snakes) offer a unique model system for testing hypotheses about the evolutionary transition from oviparity (egg-laying) to viviparity (live-bearing) in amniote vertebrates. The evolution of squamate viviparity has occurred remarkably frequently (>108 times) and has resulted in major changes in reproductive physiology. Such frequent changes in reproductive strategy pose two questions: (1) what are the molecular mechanisms responsible for the evolution of squamate viviparity? (2) Are these molecular mechanisms the same for separate origins of viviparity? Molecular approaches, such as RT-PCR, in situ hybridisation, Western blotting and immunofluorescence, have been invaluable for identifying genes and proteins that are involved in squamate placental development, materno-foetal immunotolerance, placental transport, placental angiogenesis, hormone synthesis and hormone receptor expression. However, the candidate-gene or -protein approach that has been used until now does not allow for de novo gene/protein discovery; results to date suggest that the reproductive physiologies of mammals and squamate reptiles are very similar, but this conclusion may simply be due to a limited capacity to study the subset of genes and proteins that are unique to reptiles. Progress has also been slowed by the lack of appropriate molecular and genomic resources for squamate reptiles. The advent of next-generation sequencing provides a relatively inexpensive way to conduct rapid high-throughput sequencing of genomes and transcriptomes. We discuss the potential use of next-generation sequencing technologies to analyse differences in gene expression between oviparous and viviparous squamates, provide important sequence information for reptiles, and generate testable hypotheses for the evolution of viviparity.

  5. Genomic evolution of Saccharomyces cerevisiae under Chinese rice wine fermentation.

    PubMed

    Li, Yudong; Zhang, Weiping; Zheng, Daoqiong; Zhou, Zhan; Yu, Wenwen; Zhang, Lei; Feng, Lifang; Liang, Xinle; Guan, Wenjun; Zhou, Jingwen; Chen, Jian; Lin, Zhenguo

    2014-09-10

    Rice wine fermentation represents a unique environment for the evolution of the budding yeast, Saccharomyces cerevisiae. To understand how the selection pressure shaped the yeast genome and gene regulation, we determined the genome sequence and transcriptome of a S. cerevisiae strain YHJ7 isolated from Chinese rice wine (Huangjiu), a popular traditional alcoholic beverage in China. By comparing the genome of YHJ7 to the lab strain S288c, a Japanese sake strain K7, and a Chinese industrial bioethanol strain YJSH1, we identified many genomic sequence and structural variations in YHJ7, which are mainly located in subtelomeric regions, suggesting that these regions play an important role in genomic evolution between strains. In addition, our comparative transcriptome analysis between YHJ7 and S288c revealed a set of differentially expressed genes, including those involved in glucose transport (e.g., HXT2, HXT7) and oxidoredutase activity (e.g., AAD10, ADH7). Interestingly, many of these genomic and transcriptional variations are directly or indirectly associated with the adaptation of YHJ7 strain to its specific niches. Our molecular evolution analysis suggested that Japanese sake strains (K7/UC5) were derived from Chinese rice wine strains (YHJ7) at least approximately 2,300 years ago, providing the first molecular evidence elucidating the origin of Japanese sake strains. Our results depict interesting insights regarding the evolution of yeast during rice wine fermentation, and provided a valuable resource for genetic engineering to improve industrial wine-making strains. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  6. Compensatory strategies for reducing interpersonal discrimination: the effectiveness of acknowledgments, increased positivity, and individuating information.

    PubMed

    Singletary, Sarah L; Hebl, Michelle R

    2009-05-01

    Previous research has revealed, across a number of contexts, that stigmatized individuals are the recipients of interpersonal discrimination (e.g., M. R. Hebl, J. B. Foster, L. M. Mannix, & J. F. Dovidio, 2002). Such discrimination has been linked to a number of negative outcomes in the workplace, both for stigmatized individuals and for organizations as a whole (see, e.g., E. B. King, J. L. Shapiro, M. R. Hebl, S. L. Singletary, & S. Turner, 2006; C. O. Word, M. P. Zanna, & J. Cooper, 1974). The current research examines 3 individual-level compensatory strategies aimed at reducing interpersonal discrimination. Results reveal that compensatory strategies are successful in reducing interpersonal discrimination in job application contexts and that such strategies uniquely benefit stigmatized individuals. (c) 2009 APA, all rights reserved.

  7. Differential Gene Expression During Compensatory Sprouting of Dendrites in the Auditory System of the Cricket Gryllus bimaculatus

    PubMed Central

    Horch, Hadley W.; McCarthy, Sarah S.; Johansen, Susan L.; Harris, James M.

    2013-01-01

    Neurons that lose their pre-synaptic partners due to injury usually retract or die. However, when the auditory interneurons of the cricket are denervated, dendrites respond by growing across the midline and forming novel synapses with the opposite auditory afferents. Suppression subtractive hybridization was used to detect transcriptional changes three days after denervation. This is a stage at which we demonstrate robust compensatory dendritic sprouting. While 49 unique candidates were downregulated, no sufficiently upregulated candidates were identified at this time point. Several candidates identified in this study are known to influence the translation and degradation of proteins in other systems. The potential role of these factors in the compensatory sprouting of cricket auditory interneurons in response to denervation is discussed. PMID:19453768

  8. ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: CO Luminosity Functions and the Evolution of the Cosmic Density of Molecular Gas

    NASA Astrophysics Data System (ADS)

    Decarli, Roberto; Walter, Fabian; Aravena, Manuel; Carilli, Chris; Bouwens, Rychard; da Cunha, Elisabete; Daddi, Emanuele; Ivison, R. J.; Popping, Gergö; Riechers, Dominik; Smail, Ian R.; Swinbank, Mark; Weiss, Axel; Anguita, Timo; Assef, Roberto J.; Bauer, Franz E.; Bell, Eric F.; Bertoldi, Frank; Chapman, Scott; Colina, Luis; Cortes, Paulo C.; Cox, Pierre; Dickinson, Mark; Elbaz, David; Gónzalez-López, Jorge; Ibar, Edo; Infante, Leopoldo; Hodge, Jacqueline; Karim, Alex; Le Fevre, Olivier; Magnelli, Benjamin; Neri, Roberto; Oesch, Pascal; Ota, Kazuaki; Rix, Hans-Walter; Sargent, Mark; Sheth, Kartik; van der Wel, Arjen; van der Werf, Paul; Wagg, Jeff

    2016-12-01

    In this paper we use ASPECS, the ALMA Spectroscopic Survey in the Hubble Ultra Deep Field in band 3 and band 6, to place blind constraints on the CO luminosity function and the evolution of the cosmic molecular gas density as a function of redshift up to z ˜ 4.5. This study is based on galaxies that have been selected solely through their CO emission and not through any other property. In all of the redshift bins the ASPECS measurements reach the predicted “knee” of the CO luminosity function (around 5 × 109 K km s-1 pc2). We find clear evidence of an evolution in the CO luminosity function with respect to z ˜ 0, with more CO-luminous galaxies present at z ˜ 2. The observed galaxies at z ˜ 2 also appear more gas-rich than predicted by recent semi-analytical models. The comoving cosmic molecular gas density within galaxies as a function of redshift shows a drop by a factor of 3-10 from z ˜ 2 to z ˜ 0 (with significant error bars), and possibly a decline at z > 3. This trend is similar to the observed evolution of the cosmic star formation rate density. The latter therefore appears to be at least partly driven by the increased availability of molecular gas reservoirs at the peak of cosmic star formation (z ˜ 2).

  9. Structural evolution of dilute magnetic (Sn,Mn)Se films grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Kanzyuba, Vasily; Dong, Sining; Liu, Xinyu; Li, Xiang; Rouvimov, Sergei; Okuno, Hanako; Mariette, Henri; Zhang, Xueqiang; Ptasinska, Sylwia; Tracy, Brian D.; Smith, David J.; Dobrowolska, Margaret; Furdyna, Jacek K.

    2017-02-01

    We describe the structural evolution of dilute magnetic (Sn,Mn)Se films grown by molecular beam epitaxy on GaAs (111) substrates, as revealed by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. When the Mn concentration is increased, the lattice of the ternary (Sn,Mn)Se films evolves quasi-coherently from a SnSe2 two-dimensional (2D) crystal structure into a more complex quasi-2D lattice rearrangement, ultimately transforming into the magnetically concentrated antiferromagnetic MnSe 3D rock-salt structure as Mn approaches 50 at. % of this material. These structural transformations are expected to underlie the evolution of magnetic properties of this ternary system reported earlier in the literature.

  10. PAL: an object-oriented programming library for molecular evolution and phylogenetics.

    PubMed

    Drummond, A; Strimmer, K

    2001-07-01

    Phylogenetic Analysis Library (PAL) is a collection of Java classes for use in molecular evolution and phylogenetics. PAL provides a modular environment for the rapid construction of both special-purpose and general analysis programs. PAL version 1.1 consists of 145 public classes or interfaces in 13 packages, including classes for models of character evolution, maximum-likelihood estimation, and the coalescent, with a total of more than 27000 lines of code. The PAL project is set up as a collaborative project to facilitate contributions from other researchers. AVAILIABILTY: The program is free and is available at http://www.pal-project.org. It requires Java 1.1 or later. PAL is licensed under the GNU General Public License.

  11. Trends in Karyotype Evolution in Astyanax (Teleostei, Characiformes, Characidae): Insights From Molecular Data

    PubMed Central

    Pazza, Rubens; Dergam, Jorge A.; Kavalco, Karine F.

    2018-01-01

    The study of patterns and evolutionary processes in neotropical fish is not always an easy task due the wide distribution of major fish groups in large and extensive river basins. Thus, it is not always possible to detect or correlate possible effects of chromosome rearrangements in the evolution of biodiversity. In the Astyanax genus, chromosome data obtained since the 1970s have shown evidence of cryptic species, karyotypic plasticity, supernumerary chromosomes, triploidies, and minor chromosomal rearrangements. In the present work, we map and discuss the main chromosomal events compatible with the molecular evolution of the genus Astyanax (Characiformes, Characidae) using mitochondrial DNA sequence data, in the search for major chromosome evolutionary trends within this taxon. PMID:29713335

  12. Evolution of bacterial virulence.

    PubMed

    Diard, Médéric; Hardt, Wolf-Dietrich

    2017-09-01

    Bacterial virulence is highly dynamic and context-dependent. For this reason, it is challenging to predict how molecular changes affect the growth of a pathogen in a host and its spread in host population. Two schools of thought have taken quite different directions to decipher the underlying principles of bacterial virulence. While molecular infection biology is focusing on the basic mechanisms of the pathogen-host interaction, evolution biology takes virulence as one of several parameters affecting pathogen spread in a host population. We review both approaches and discuss how they can complement each other in order to obtain a comprehensive understanding of bacterial virulence, its emergence, maintenance and evolution. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Automatic Evolution of Molecular Nanotechnology Designs

    NASA Technical Reports Server (NTRS)

    Globus, Al; Lawton, John; Wipke, Todd; Saini, Subhash (Technical Monitor)

    1998-01-01

    This paper describes strategies for automatically generating designs for analog circuits at the molecular level. Software maps out the edges and vertices of potential nanotechnology systems on graphs, then selects appropriate ones through evolutionary or genetic paradigms.

  14. Interplay between Chaperones and Protein Disorder Promotes the Evolution of Protein Networks

    PubMed Central

    Pechmann, Sebastian; Frydman, Judith

    2014-01-01

    Evolution is driven by mutations, which lead to new protein functions but come at a cost to protein stability. Non-conservative substitutions are of interest in this regard because they may most profoundly affect both function and stability. Accordingly, organisms must balance the benefit of accepting advantageous substitutions with the possible cost of deleterious effects on protein folding and stability. We here examine factors that systematically promote non-conservative mutations at the proteome level. Intrinsically disordered regions in proteins play pivotal roles in protein interactions, but many questions regarding their evolution remain unanswered. Similarly, whether and how molecular chaperones, which have been shown to buffer destabilizing mutations in individual proteins, generally provide robustness during proteome evolution remains unclear. To this end, we introduce an evolutionary parameter λ that directly estimates the rate of non-conservative substitutions. Our analysis of λ in Escherichia coli, Saccharomyces cerevisiae, and Homo sapiens sequences reveals how co- and post-translationally acting chaperones differentially promote non-conservative substitutions in their substrates, likely through buffering of their destabilizing effects. We further find that λ serves well to quantify the evolution of intrinsically disordered proteins even though the unstructured, thus generally variable regions in proteins are often flanked by very conserved sequences. Crucially, we show that both intrinsically disordered proteins and highly re-wired proteins in protein interaction networks, which have evolved new interactions and functions, exhibit a higher λ at the expense of enhanced chaperone assistance. Our findings thus highlight an intricate interplay of molecular chaperones and protein disorder in the evolvability of protein networks. Our results illuminate the role of chaperones in enabling protein evolution, and underline the importance of the cellular context and integrated approaches for understanding proteome evolution. We feel that the development of λ may be a valuable addition to the toolbox applied to understand the molecular basis of evolution. PMID:24968255

  15. Three-Fingered RAVERs: Rapid Accumulation of Variations in Exposed Residues of Snake Venom Toxins

    PubMed Central

    Sunagar, Kartik; Jackson, Timothy N. W.; Undheim, Eivind A. B.; Ali, Syed. A.; Antunes, Agostinho; Fry, Bryan G.

    2013-01-01

    Three-finger toxins (3FTx) represent one of the most abundantly secreted and potently toxic components of colubrid (Colubridae), elapid (Elapidae) and psammophid (Psammophiinae subfamily of the Lamprophidae) snake venom arsenal. Despite their conserved structural similarity, they perform a diversity of biological functions. Although they are theorised to undergo adaptive evolution, the underlying diversification mechanisms remain elusive. Here, we report the molecular evolution of different 3FTx functional forms and show that positively selected point mutations have driven the rapid evolution and diversification of 3FTx. These diversification events not only correlate with the evolution of advanced venom delivery systems (VDS) in Caenophidia, but in particular the explosive diversification of the clade subsequent to the evolution of a high pressure, hollow-fanged VDS in elapids, highlighting the significant role of these toxins in the evolution of advanced snakes. We show that Type I, II and III α-neurotoxins have evolved with extreme rapidity under the influence of positive selection. We also show that novel Oxyuranus/Pseudonaja Type II forms lacking the apotypic loop-2 stabilising cysteine doublet characteristic of Type II forms are not phylogenetically basal in relation to other Type IIs as previously thought, but are the result of secondary loss of these apotypic cysteines on at least three separate occasions. Not all 3FTxs have evolved rapidly: κ-neurotoxins, which form non-covalently associated heterodimers, have experienced a relatively weaker influence of diversifying selection; while cytotoxic 3FTx, with their functional sites, dispersed over 40% of the molecular surface, have been extremely constrained by negative selection. We show that the a previous theory of 3FTx molecular evolution (termed ASSET) is evolutionarily implausible and cannot account for the considerable variation observed in very short segments of 3FTx. Instead, we propose a theory of Rapid Accumulation of Variations in Exposed Residues (RAVER) to illustrate the significance of point mutations, guided by focal mutagenesis and positive selection in the evolution and diversification of 3FTx. PMID:24253238

  16. Driving simulation in the clinic: testing visual exploratory behavior in daily life activities in patients with visual field defects.

    PubMed

    Hamel, Johanna; Kraft, Antje; Ohl, Sven; De Beukelaer, Sophie; Audebert, Heinrich J; Brandt, Stephan A

    2012-09-18

    Patients suffering from homonymous hemianopia after infarction of the posterior cerebral artery (PCA) report different degrees of constraint in daily life, despite similar visual deficits. We assume this could be due to variable development of compensatory strategies such as altered visual scanning behavior. Scanning compensatory therapy (SCT) is studied as part of the visual training after infarction next to vision restoration therapy. SCT consists of learning to make larger eye movements into the blind field enlarging the visual field of search, which has been proven to be the most useful strategy(1), not only in natural search tasks but also in mastering daily life activities(2). Nevertheless, in clinical routine it is difficult to identify individual levels and training effects of compensatory behavior, since it requires measurement of eye movements in a head unrestrained condition. Studies demonstrated that unrestrained head movements alter the visual exploratory behavior compared to a head-restrained laboratory condition(3). Martin et al.(4) and Hayhoe et al.(5) showed that behavior demonstrated in a laboratory setting cannot be assigned easily to a natural condition. Hence, our goal was to develop a study set-up which uncovers different compensatory oculomotor strategies quickly in a realistic testing situation: Patients are tested in the clinical environment in a driving simulator. SILAB software (Wuerzburg Institute for Traffic Sciences GmbH (WIVW)) was used to program driving scenarios of varying complexity and recording the driver's performance. The software was combined with a head mounted infrared video pupil tracker, recording head- and eye-movements (EyeSeeCam, University of Munich Hospital, Clinical Neurosciences). The positioning of the patient in the driving simulator and the positioning, adjustment and calibration of the camera is demonstrated. Typical performances of a patient with and without compensatory strategy and a healthy control are illustrated in this pilot study. Different oculomotor behaviors (frequency and amplitude of eye- and head-movements) are evaluated very quickly during the drive itself by dynamic overlay pictures indicating where the subjects gaze is located on the screen, and by analyzing the data. Compensatory gaze behavior in a patient leads to a driving performance comparable to a healthy control, while the performance of a patient without compensatory behavior is significantly worse. The data of eye- and head-movement-behavior as well as driving performance are discussed with respect to different oculomotor strategies and in a broader context with respect to possible training effects throughout the testing session and implications on rehabilitation potential.

  17. Longitudinal Changes in Active Bone Marrow for Cervical Cancer Patients Treated With Concurrent Chemoradiation Therapy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Noticewala, Sonal S.; Li, Nan; Williamson, Casey W.

    Purpose: To quantify longitudinal changes in active bone marrow (ABM) distributions within unirradiated (extrapelvic) and irradiated (pelvic) bone marrow (BM) in cervical cancer patients treated with concurrent chemoradiation therapy (CRT). Methods and Materials: We sampled 39 cervical cancer patients treated with CRT, of whom 25 were treated with concurrent cisplatin (40 mg/m{sup 2}) and 14 were treated with cisplatin (40 mg/m{sup 2}) plus gemcitabine (50-125 mg/m{sup 2}) (C/G). Patients underwent {sup 18}F-fluorodeoxyglucose positron emission tomographic/computed tomographic imaging at baseline and 1.5 to 6.0 months after treatment. ABM was defined as the subvolume of bone with standardized uptake value (SUV) above the mean SUV ofmore » the total bone. The primary aim was to measure the compensatory response, defined as the change in the log of the ratio of extrapelvic versus pelvic ABM percentage from baseline to after treatment. We also quantified the change in the proportion of ABM and mean SUV in pelvic and extrapelvic BM using a 2-sided paired t test. Results: We observed a significant increase in the overall extrapelvic compensatory response after CRT (0.381; 95% confidence interval [CI]: 0.312, 0.449) and separately in patients treated with cisplatin (0.429; 95% CI: 0.340, 0.517) and C/G (0.294; 95% CI: 0.186, 0.402). We observed a trend toward higher compensatory response in patients treated with cisplatin compared with C/G (P=.057). Pelvic ABM percentage was reduced after CRT both in patients receiving cisplatin (P<.001) and in those receiving C/G (P<.001), whereas extrapelvic ABM percentage was increased in patients receiving cisplatin (P<.001) and C/G (P<.001). The mean SUV in pelvic structures was lower after CRT with both cisplatin (P<.001) and C/G (P<.001). The mean SUV appeared lower in extrapelvic structures after CRT in patients treated with C/G (P=.076) but not with cisplatin (P=.942). We also observed that older age and more intense chemotherapy regimens were correlated with a decreased compensatory response on multivariable analysis. In patients treated with C/G, mean pelvic bone marrow dose was found to be negatively correlated with the compensatory response. Conclusion: Patients have differing subacute compensatory responses after CRT, owing to variable recovery in unirradiated marrow. Intensive chemotherapy regimens appear to decrease the extrapelvic compensatory response, which may lead to increased hematologic toxicity.« less

  18. Active Cocatalysts for Photocatalytic Hydrogen Evolution Derived from Nickel or Cobalt Amine Complexes.

    PubMed

    Huang, Yi; Zhang, Bin

    2017-11-20

    A cost-effective and robust strategy for the anchoring of molecular hydrogen evolution cocatalysts onto semiconductors has recently been reported. The composite materials were highly efficient and stable towards photocatalytic H 2 evolution. This study provides guidance for the design and construction of highly active heterogeneous photocatalysts. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Genomics and Evolution in Traditional Medicinal Plants: Road to a Healthier Life

    PubMed Central

    Hao, Da-Cheng; Xiao, Pei-Gen

    2015-01-01

    Medicinal plants have long been utilized in traditional medicine and ethnomedicine worldwide. This review presents a glimpse of the current status of and future trends in medicinal plant genomics, evolution, and phylogeny. These dynamic fields are at the intersection of phytochemistry and plant biology and are concerned with the evolution mechanisms and systematics of medicinal plant genomes, origin and evolution of the plant genotype and metabolic phenotype, interaction between medicinal plant genomes and their environment, the correlation between genomic diversity and metabolite diversity, and so on. Use of the emerging high-end genomic technologies can be expanded from crop plants to traditional medicinal plants, in order to expedite medicinal plant breeding and transform them into living factories of medicinal compounds. The utility of molecular phylogeny and phylogenomics in predicting chemodiversity and bioprospecting is also highlighted within the context of natural-product-based drug discovery and development. Representative case studies of medicinal plant genome, phylogeny, and evolution are summarized to exemplify the expansion of knowledge pedigree and the paradigm shift to the omics-based approaches, which update our awareness about plant genome evolution and enable the molecular breeding of medicinal plants and the sustainable utilization of plant pharmaceutical resources. PMID:26461812

  20. Genomics and Evolution in Traditional Medicinal Plants: Road to a Healthier Life.

    PubMed

    Hao, Da-Cheng; Xiao, Pei-Gen

    2015-01-01

    Medicinal plants have long been utilized in traditional medicine and ethnomedicine worldwide. This review presents a glimpse of the current status of and future trends in medicinal plant genomics, evolution, and phylogeny. These dynamic fields are at the intersection of phytochemistry and plant biology and are concerned with the evolution mechanisms and systematics of medicinal plant genomes, origin and evolution of the plant genotype and metabolic phenotype, interaction between medicinal plant genomes and their environment, the correlation between genomic diversity and metabolite diversity, and so on. Use of the emerging high-end genomic technologies can be expanded from crop plants to traditional medicinal plants, in order to expedite medicinal plant breeding and transform them into living factories of medicinal compounds. The utility of molecular phylogeny and phylogenomics in predicting chemodiversity and bioprospecting is also highlighted within the context of natural-product-based drug discovery and development. Representative case studies of medicinal plant genome, phylogeny, and evolution are summarized to exemplify the expansion of knowledge pedigree and the paradigm shift to the omics-based approaches, which update our awareness about plant genome evolution and enable the molecular breeding of medicinal plants and the sustainable utilization of plant pharmaceutical resources.

  1. Stability-activity tradeoffs constrain the adaptive evolution of RubisCO.

    PubMed

    Studer, Romain A; Christin, Pascal-Antoine; Williams, Mark A; Orengo, Christine A

    2014-02-11

    A well-known case of evolutionary adaptation is that of ribulose-1,5-bisphosphate carboxylase (RubisCO), the enzyme responsible for fixation of CO2 during photosynthesis. Although the majority of plants use the ancestral C3 photosynthetic pathway, many flowering plants have evolved a derived pathway named C4 photosynthesis. The latter concentrates CO2, and C4 RubisCOs consequently have lower specificity for, and faster turnover of, CO2. The C4 forms result from convergent evolution in multiple clades, with substitutions at a small number of sites under positive selection. To understand the physical constraints on these evolutionary changes, we reconstructed in silico ancestral sequences and 3D structures of RubisCO from a large group of related C3 and C4 species. We were able to precisely track their past evolutionary trajectories, identify mutations on each branch of the phylogeny, and evaluate their stability effect. We show that RubisCO evolution has been constrained by stability-activity tradeoffs similar in character to those previously identified in laboratory-based experiments. The C4 properties require a subset of several ancestral destabilizing mutations, which from their location in the structure are inferred to mainly be involved in enhancing conformational flexibility of the open-closed transition in the catalytic cycle. These mutations are near, but not in, the active site or at intersubunit interfaces. The C3 to C4 transition is preceded by a sustained period in which stability of the enzyme is increased, creating the capacity to accept the functionally necessary destabilizing mutations, and is immediately followed by compensatory mutations that restore global stability.

  2. Proceedings: Conference on Compensatory/Remedial Education, April 3 and 4, 1975. Occasional Paper No. 24.

    ERIC Educational Resources Information Center

    Larson, Howard B., Ed.; Olswang, Steven G., Ed.

    The intent of this annual conference is to provide a medium of exchange for practitioners in the field, with each person acting as a resource person for the others. To provide topical focuses, two presentations were made: Dr. Joan Roloff discussed "The Place of the Learning Center in Remedial/Compensatory Education in Community Colleges," and Dr.…

  3. What We Know about Compensatory Education: A Compendium. What Does Work? What Does Not Work? What Role Does Evaluation Play?

    ERIC Educational Resources Information Center

    Austin Independent School District, TX. Office of Research and Evaluation.

    The Office of Research and Evaluation (ORE) has been evaluating compensatory education programs in the Austin Independent School District for 10 years. This volume is an attempt to pull together many of those useful, intermittently timely findings into a handy reference volume. The contributions to this volume actually span the 10-year history of…

  4. Biomechanics of compensatory mechanisms in spinal-pelvic complex

    NASA Astrophysics Data System (ADS)

    Ivanov, D. V.; Hominets, V. V.; Kirillova, I. V.; Kossovich, L. Yu; Kudyashev, A. L.; Teremshonok, A. V.

    2018-04-01

    3D geometric solid computer model of spinal-pelvic complex was constructed on the basis of computed tomography and full body X-ray in standing position data. The constructed model was used for biomechanical analysis of compensatory mechanisms arising in the spine with anteversion and retroversion of the pelvis. The results of numerical biomechanical 3D modeling are in good agreement with the clinical data.

  5. Data Analysis of the 1968-69 Survey of Compensatory Education (Title I). Final Report.

    ERIC Educational Resources Information Center

    Glass, Gene V.; And Others

    In this report, the results of analyses of data from ESEA Title I Program evaluations collected in the 1969 Survey of Compensatory Education are presented. These data analyses bear on the evaluation of the operations and impact of the programs in 9236 school districts and 3219 elementary schools, involving 215,995 teachers of 5,733,976 pupils in…

  6. An Evaluation of the Cost Effectiveness of Alternative Compensatory Reading Programs, Volume IV: Cost Analysis of Summer Programs. Final Report.

    ERIC Educational Resources Information Center

    Al-Salam, Nabeel; Flynn, Donald L.

    This report describes the results of a study of the cost and cost effectiveness of 27 summer reading programs, carried through as part of a large-scale evaluation of compensatory reading programs. Three other reports describe cost and cost-effectiveness studies of programs during the regular school year. On an instructional-hour basis, the total…

  7. Interpreting problematic behavior: systematic compensatory adaptations as emergent phenomena in autism.

    PubMed

    Damico, Jack S; Nelson, Ryan L

    2005-01-01

    Based upon an emergent account of pragmatic ability and disability, this article provides theoretical and empirical support for a conceptually deeper understanding of some systematic behaviors that have served as diagnostic indices in communicatively impaired populations. Specifically, by employing conversation analysis, several examples of problematic behaviors in autism are analysed as a specific type of compensatory adaptation. Theoretical and clinical implications are discussed.

  8. Compensatory value of urban trees in the United States

    Treesearch

    David J. Nowak; Daniel E. Crane; John F. Dwyer

    2002-01-01

    Understanding the value of an urban forest can give decision makers a better foundation for urban tree namagement. Based on tree-valuation methods of the Council of Tree and Landscape Appraisers and field data from eight cities, total compensatory value of tree populations in U.S. cities ranges from $101 million in Jersey City, New Jersey, to $6.2 billion in New York,...

  9. Compensatory changes in CYP expression in three different toxicology mouse models: CAR-null, Cyp3a-null, and Cyp2b9/10/13-null mice

    PubMed Central

    Kumar, Ramiya; Mota, Linda C.; Litoff, Elizabeth J.; Rooney, John P.; Boswell, W. Tyler; Courter, Elliott; Henderson, Charles M.; Hernandez, Juan P.; Corton, J. Christopher; Moore, David D.

    2017-01-01

    Targeted mutant models are common in mechanistic toxicology experiments investigating the absorption, metabolism, distribution, or elimination (ADME) of chemicals from individuals. Key models include those for xenosensing transcription factors and cytochrome P450s (CYP). Here we investigated changes in transcript levels, protein expression, and steroid hydroxylation of several xenobiotic detoxifying CYPs in constitutive androstane receptor (CAR)-null and two CYP-null mouse models that have subfamily members regulated by CAR; the Cyp3a-null and a newly described Cyp2b9/10/13-null mouse model. Compensatory changes in CYP expression that occur in these models may also occur in polymorphic humans, or may complicate interpretation of ADME studies performed using these models. The loss of CAR causes significant changes in several CYPs probably due to loss of CAR-mediated constitutive regulation of these CYPs. Expression and activity changes include significant repression of Cyp2a and Cyp2b members with corresponding drops in 6α- and 16β-testosterone hydroxylase activity. Further, the ratio of 6α-/15α-hydroxylase activity, a biomarker of sexual dimorphism in the liver, indicates masculinization of female CAR-null mice, suggesting a role for CAR in the regulation of sexually dimorphic liver CYP profiles. The loss of Cyp3a causes fewer changes than CAR. Nevertheless, there are compensatory changes including gender-specific increases in Cyp2a and Cyp2b. Cyp2a and Cyp2b were down-regulated in CAR-null mice, suggesting activation of CAR and potentially PXR following loss of the Cyp3a members. However, the loss of Cyp2b causes few changes in hepatic CYP transcript levels and almost no significant compensatory changes in protein expression or activity with the possible exception of 6α-hydroxylase activity. This lack of a compensatory response in the Cyp2b9/10/13-null mice is probably due to low CYP2B hepatic expression, especially in male mice. Overall, compensatory and regulatory CYP changes followed the order CAR-null > Cyp3a-null > Cyp2b-null mice. PMID:28350814

  10. Compensatory changes in CYP expression in three different toxicology mouse models: CAR-null, Cyp3a-null, and Cyp2b9/10/13-null mice.

    PubMed

    Kumar, Ramiya; Mota, Linda C; Litoff, Elizabeth J; Rooney, John P; Boswell, W Tyler; Courter, Elliott; Henderson, Charles M; Hernandez, Juan P; Corton, J Christopher; Moore, David D; Baldwin, William S

    2017-01-01

    Targeted mutant models are common in mechanistic toxicology experiments investigating the absorption, metabolism, distribution, or elimination (ADME) of chemicals from individuals. Key models include those for xenosensing transcription factors and cytochrome P450s (CYP). Here we investigated changes in transcript levels, protein expression, and steroid hydroxylation of several xenobiotic detoxifying CYPs in constitutive androstane receptor (CAR)-null and two CYP-null mouse models that have subfamily members regulated by CAR; the Cyp3a-null and a newly described Cyp2b9/10/13-null mouse model. Compensatory changes in CYP expression that occur in these models may also occur in polymorphic humans, or may complicate interpretation of ADME studies performed using these models. The loss of CAR causes significant changes in several CYPs probably due to loss of CAR-mediated constitutive regulation of these CYPs. Expression and activity changes include significant repression of Cyp2a and Cyp2b members with corresponding drops in 6α- and 16β-testosterone hydroxylase activity. Further, the ratio of 6α-/15α-hydroxylase activity, a biomarker of sexual dimorphism in the liver, indicates masculinization of female CAR-null mice, suggesting a role for CAR in the regulation of sexually dimorphic liver CYP profiles. The loss of Cyp3a causes fewer changes than CAR. Nevertheless, there are compensatory changes including gender-specific increases in Cyp2a and Cyp2b. Cyp2a and Cyp2b were down-regulated in CAR-null mice, suggesting activation of CAR and potentially PXR following loss of the Cyp3a members. However, the loss of Cyp2b causes few changes in hepatic CYP transcript levels and almost no significant compensatory changes in protein expression or activity with the possible exception of 6α-hydroxylase activity. This lack of a compensatory response in the Cyp2b9/10/13-null mice is probably due to low CYP2B hepatic expression, especially in male mice. Overall, compensatory and regulatory CYP changes followed the order CAR-null > Cyp3a-null > Cyp2b-null mice.

  11. Homochiral Evolution in Self-Assembled Chiral Polymers and Block Copolymers.

    PubMed

    Wen, Tao; Wang, Hsiao-Fang; Li, Ming-Chia; Ho, Rong-Ming

    2017-04-18

    The significance of chirality transfer is not only involved in biological systems, such as the origin of homochiral structures in life but also in man-made chemicals and materials. How the chiral bias transfers from molecular level (molecular chirality) to helical chain (conformational chirality) and then to helical superstructure or phase (hierarchical chirality) from self-assembly is vital for the chemical and biological processes in nature, such as communication, replication, and enzyme catalysis. In this Account, we summarize the methodologies for the examination of homochiral evolution at different length scales based on our recent studies with respect to the self-assembly of chiral polymers and chiral block copolymers (BCPs*). A helical (H*) phase to distinguish its P622 symmetry from that of normal hexagonally packed cylinder phase was discovered in the self-assembly of BCPs* due to the chirality effect on BCP self-assembly. Enantiomeric polylactide-containing BCPs*, polystyrene-b-poly(l-lactide) (PS-PLLA) and polystyrene-b-poly(d-lactide) (PS-PDLA), were synthesized for the examination of homochiral evolution. The optical activity (molecular chirality) of constituted chiral repeating unit in the chiral polylactide is detected by electronic circular dichroism (ECD) whereas the conformational chirality of helical polylactide chain can be explicitly determined by vibrational circular dichroism (VCD). The H* phases of the self-assembled polylactide-containing BCPs* can be directly visualized by 3D transmission electron microscopy (3D TEM) technique at which the handedness (hierarchical chirality) of the helical nanostructure is thus determined. The results from the ECD, VCD, and 3D TEM for the investigated chirality at different length scales suggest the homochiral evolution in the self-assembly of the BCPs*. For chiral polylactides, twisted lamellae in crystalline banded spherulite can be formed by dense packing scheme and effective interactions upon helical chains from self-assembly. The handedness of the twisted lamella can be determined by using rotation experiment of polarized light microscopy (PLM). Similar to the self-assembly of BCPs*, the examined results suggest the homochiral evolution in the crystallized chiral polylactides. The results presented in this Account demonstrate the notable progress in the spectral and morphological determination for the examination of molecular, conformational, and hierarchical chirality in self-assembled twisted superstructures of chiral polymers and helical phases of block copolymers and suggest the attainability of homochiral evolution in the self-assembly of chiral homopolymers and BCPs*. The suggested methodologies for the understanding of the mechanisms of the chirality transfer at different length scales provide the approaches to give Supporting Information for disclosing the mysteries of the homochiral evolution from molecular level.

  12. Cardiac Gab1 deletion leads to dilated cardiomyopathy associated with mitochondrial damage and cardiomyocyte apoptosis

    PubMed Central

    Zhao, J; Yin, M; Deng, H; Jin, F Q; Xu, S; Lu, Y; Mastrangelo, M A; Luo, H; Jin, Z G

    2016-01-01

    A vital step in the development of heart failure is the transition from compensatory cardiac hypertrophy to decompensated dilated cardiomyopathy (DCM) during cardiac remodeling under mechanical or pathological stress. However, the molecular mechanisms underlying the development of DCM and heart failure remain incompletely understood. In the present study, we investigate whether Gab1, a scaffolding adaptor protein, protects against hemodynamic stress-induced DCM and heat failure. We first observed that the protein levels of Gab1 were markedly reduced in hearts from human patients with DCM and from mice with experimental viral myocarditis in which DCM developed. Next, we generated cardiac-specific Gab1 knockout mice (Gab1-cKO) and found that Gab-cKO mice developed DCM in hemodynamic stress-dependent and age-dependent manners. Under transverse aorta constriction (TAC), Gab1-cKO mice rapidly developed decompensated DCM and heart failure, whereas Gab1 wild-type littermates exhibited adaptive left ventricular hypertrophy without changes in cardiac function. Mechanistically, we showed that Gab1-cKO mouse hearts displayed severe mitochondrial damages and increased cardiomyocyte apoptosis. Loss of cardiac Gab1 in mice impaired Gab1 downstream MAPK signaling pathways in the heart under TAC. Gene profiles further revealed that ablation of Gab1 in heart disrupts the balance of anti- and pro-apoptotic genes in cardiomyocytes. These results demonstrate that cardiomyocyte Gab1 is a critical regulator of the compensatory cardiac response to aging and hemodynamic stress. These findings may provide new mechanistic insights and potential therapeutic target for DCM and heart failure. PMID:26517531

  13. Genetic abolishment of hepatocyte proliferation activates hepatic stem cells.

    PubMed

    Endo, Yoko; Zhang, Mingjun; Yamaji, Sachie; Cang, Yong

    2012-01-01

    Quiescent hepatic stem cells (HSCs) can be activated when hepatocyte proliferation is compromised. Chemical injury rodent models have been widely used to study the localization, biomarkers, and signaling pathways in HSCs, but these models usually exhibit severe promiscuous toxicity and fail to distinguish damaged and non-damaged cells. Our goal is to establish new animal models to overcome these limitations, thereby providing new insights into HSC biology and application. We generated mutant mice with constitutive or inducible deletion of Damaged DNA Binding protein 1 (DDB1), an E3 ubiquitin ligase, in hepatocytes. We characterized the molecular mechanism underlying the compensatory activation and the properties of oval cells (OCs) by methods of mouse genetics, immuno-staining, cell transplantation and gene expression profiling. We show that deletion of DDB1 abolishes self-renewal capacity of mouse hepatocytes in vivo, leading to compensatory activation and proliferation of DDB1-expressing OCs. Partially restoring proliferation of DDB1-deficient hepatocytes by ablation of p21, a substrate of DDB1 E3 ligase, alleviates OC proliferation. Purified OCs express both hepatocyte and cholangiocyte markers, form colonies in vitro, and differentiate to hepatocytes after transplantation. Importantly, the DDB1 mutant mice exhibit very minor liver damage, compared to a chemical injury model. Microarray analysis reveals several previously unrecognized markers, including Reelin, enriched in oval cells. Here we report a genetic model in which irreversible inhibition of hepatocyte duplication results in HSC-driven liver regeneration. The DDB1 mutant mice can be broadly applied to studies of HSC differentiation, HSC niche and HSCs as origin of liver cancer.

  14. Removal of area CA3 from hippocampal slices induces postsynaptic plasticity at Schaffer collateral synapses that normalizes CA1 pyramidal cell discharge.

    PubMed

    Dumas, Theodore C; Uttaro, Michael R; Barriga, Carolina; Brinkley, Tiffany; Halavi, Maryam; Wright, Susan N; Ferrante, Michele; Evans, Rebekah C; Hawes, Sarah L; Sanders, Erin M

    2018-06-21

    Neural networks that undergo acute insults display remarkable reorganization. This injury related plasticity is thought to permit recovery of function in the face of damage that cannot be reversed. Previously, an increase in the transmission strength at Schaffer collateral to CA1 pyramidal cell synapses was observed after long-term activity reduction in organotypic hippocampal slices. Here we report that, following acute preparation of adult rat hippocampal slices and surgical removal of area CA3, input to area CA1 was reduced and Schaffer collateral synapses underwent functional strengthening. This increase in synaptic strength was limited to Schaffer collateral inputs (no alteration to temporoammonic synapses) and acted to normalize postsynaptic discharge, supporting a homeostatic or compensatory response. Short-term plasticity was not altered, but an increase in immunohistochemical labeling of GluA1 subunits was observed in the stratum radiatum (but not stratum moleculare), suggesting increased numbers of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and a postsynaptic locus of expression. Combined, these data support the idea that, in response to the reduction in presynaptic activity caused by removal of area CA3, Schaffer collateral synapses undergo a relatively rapid increase in functional efficacy likely supported by insertion of more AMPARs, which maintains postsynaptic excitability in CA1 pyramidal neurons. This novel fast compensatory plasticity exhibits properties that would allow it to maintain optimal network activity levels in the hippocampus, a brain structure lauded for its ongoing experience-dependent malleability. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. A post-transcriptional compensatory pathway in heterozygous ventricular myosin light chain 2-deficient mice results in lack of gene dosage effect during normal cardiac growth or hypertrophy.

    PubMed

    Minamisawa, S; Gu, Y; Ross, J; Chien, K R; Chen, J

    1999-04-09

    Our previous study of homozygous mutants of the ventricular specific isoform of myosin light chain 2 (mlc-2v) demonstrated that mlc-2v plays an essential role in murine heart development (Chen, J., Kubalak, S. W., Minamisawa, S., Price, R. L., Becker, K. D., Hickey, R., Ross, J., Jr., and Chien, K. R. (1998) J. Biol. Chem. 273, 1252-1256). As gene dosage of some myofibrillar proteins can affect muscle function, we have analyzed heterozygous mutants in depth. Ventricles of heterozygous mutants displayed a 50% reduction in mlc-2v mRNA, yet expressed normal levels of protein both under basal conditions and following induction of cardiac hypertrophy by aortic constriction. Heterozygous mutants exhibited cardiac function comparable to that of wild-type littermate controls both prior to and following aortic constriction. There were no significant differences in contractility and responses to calcium between wild-type and heterozygous unloaded cardiomyocytes. We conclude that heterozygous mutants show neither a molecular nor a physiological cardiac phenotype either at base line or following hypertrophic stimuli. These results suggest that post-transcriptional compensatory mechanisms play a major role in maintaining the level of MLC-2v protein in murine hearts. In addition, as our mlc-2v knockout mutants were created by a knock-in of Cre recombinase into the endogenous mlc-2v locus, this study demonstrates that heterozygous mlc-2v cre knock-in mice are appropriate for ventricular specific gene targeting.

  16. Retinal compensatory changes after light damage in albino mice

    PubMed Central

    Montalbán-Soler, Luis; Alarcón-Martínez, Luis; Jiménez-López, Manuel; Salinas-Navarro, Manuel; Galindo-Romero, Caridad; Bezerra de Sá, Fabrízio; García-Ayuso, Diego; Avilés-Trigueros, Marcelino; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta

    2012-01-01

    Purpose To investigate the anatomic and functional changes triggered by light exposure in the albino mouse retina and compare them with those observed in the albino rat. Methods BALB/c albino mice were exposed to 3,000 lx of white light during 24 h and their retinas analyzed from 1 to 180 days after light exposure (ALE). Left pupil mydriasis was induced with topical atropine. Retinal function was analyzed by electroretinographic (ERG) recording. To assess retinal degeneration, hematoxylin and eosin staining, the TdT-mediated dUTP nick-end labeling (TUNEL) technique, and quantitative immunohistofluorescence for synaptophysin and protein kinase Cα (PKCα) were used in cross sections. Intravenous injection of horseradish peroxidase and Fluoro-Gold™ tracing were used in whole-mounted retinas to study the retinal vasculature and the retinal ganglion cell (RGC) population, respectively. Results Light exposure caused apoptotic photoreceptor death in the central retina. This death was more severe in the dorsal than in the ventral retina, sparing the periphery. Neither retinal vascular leakage nor retinal ganglion cell death was observed ALE. The electroretinographic a-wave was permanently impaired, while the b-wave decreased but recovered gradually by 180 days ALE. The scotopic threshold responses, associated with the inner retinal function, diminished at first but recovered completely by 14 days ALE. This functional recovery was concomitant with the upregulation of protein kinase Cα and synaptophysin. Similar results were obtained in both eyes, irrespective of mydriasis. Conclusions In albino mice, light exposure induces substantial retinal damage, but the surviving photoreceptors, together with compensatory morphological/molecular changes, allow an important restoration of the retinal function. PMID:22509098

  17. Genetic Abolishment of Hepatocyte Proliferation Activates Hepatic Stem Cells

    PubMed Central

    Endo, Yoko; Zhang, Mingjun; Yamaji, Sachie; Cang, Yong

    2012-01-01

    Quiescent hepatic stem cells (HSCs) can be activated when hepatocyte proliferation is compromised. Chemical injury rodent models have been widely used to study the localization, biomarkers, and signaling pathways in HSCs, but these models usually exhibit severe promiscuous toxicity and fail to distinguish damaged and non-damaged cells. Our goal is to establish new animal models to overcome these limitations, thereby providing new insights into HSC biology and application. We generated mutant mice with constitutive or inducible deletion of Damaged DNA Binding protein 1 (DDB1), an E3 ubiquitin ligase, in hepatocytes. We characterized the molecular mechanism underlying the compensatory activation and the properties of oval cells (OCs) by methods of mouse genetics, immuno-staining, cell transplantation and gene expression profiling. We show that deletion of DDB1 abolishes self-renewal capacity of mouse hepatocytes in vivo, leading to compensatory activation and proliferation of DDB1-expressing OCs. Partially restoring proliferation of DDB1-deficient hepatocytes by ablation of p21, a substrate of DDB1 E3 ligase, alleviates OC proliferation. Purified OCs express both hepatocyte and cholangiocyte markers, form colonies in vitro, and differentiate to hepatocytes after transplantation. Importantly, the DDB1 mutant mice exhibit very minor liver damage, compared to a chemical injury model. Microarray analysis reveals several previously unrecognized markers, including Reelin, enriched in oval cells. Here we report a genetic model in which irreversible inhibition of hepatocyte duplication results in HSC-driven liver regeneration. The DDB1 mutant mice can be broadly applied to studies of HSC differentiation, HSC niche and HSCs as origin of liver cancer. PMID:22384083

  18. Identification of amino acid substitutions with compensational effects in the attachment protein of canine distemper virus.

    PubMed

    Sattler, Ursula; Khosravi, Mojtaba; Avila, Mislay; Pilo, Paola; Langedijk, Johannes P; Ader-Ebert, Nadine; Alves, Lisa A; Plattet, Philippe; Origgi, Francesco C

    2014-07-01

    The hemagglutinin (H) gene of canine distemper virus (CDV) encodes the receptor-binding protein. This protein, together with the fusion (F) protein, is pivotal for infectivity since it contributes to the fusion of the viral envelope with the host cell membrane. Of the two receptors currently known for CDV (nectin-4 and the signaling lymphocyte activation molecule [SLAM]), SLAM is considered the most relevant for host susceptibility. To investigate how evolution might have impacted the host-CDV interaction, we examined the functional properties of a series of missense single nucleotide polymorphisms (SNPs) naturally accumulating within the H-gene sequences during the transition between two distinct but related strains. The two strains, a wild-type strain and a consensus strain, were part of a single continental outbreak in European wildlife and occurred in distinct geographical areas 2 years apart. The deduced amino acid sequence of the two H genes differed at 5 residues. A panel of mutants carrying all the combinations of the SNPs was obtained by site-directed mutagenesis. The selected mutant, wild type, and consensus H proteins were functionally evaluated according to their surface expression, SLAM binding, fusion protein interaction, and cell fusion efficiencies. The results highlight that the most detrimental functional effects are associated with specific sets of SNPs. Strikingly, an efficient compensational system driven by additional SNPs appears to come into play, virtually neutralizing the negative functional effects. This system seems to contribute to the maintenance of the tightly regulated function of the H-gene-encoded attachment protein. Importance: To investigate how evolution might have impacted the host-canine distemper virus (CDV) interaction, we examined the functional properties of naturally occurring single nucleotide polymorphisms (SNPs) in the hemagglutinin gene of two related but distinct strains of CDV. The hemagglutinin gene encodes the attachment protein, which is pivotal for infection. Our results show that few SNPs have a relevant detrimental impact and they generally appear in specific combinations (molecular signatures). These drastic negative changes are neutralized by compensatory mutations, which contribute to maintenance of an overall constant bioactivity of the attachment protein. This compensational mechanism might reflect the reaction of the CDV machinery to the changes occurring in the virus following antigenic variations critical for virulence. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  19. First simultaneous detection of terrestrial ionospheric molecular ions in the Earth's inner magnetosphere and at the Moon

    NASA Astrophysics Data System (ADS)

    Dandouras, I.; Poppe, A. R.; Fillingim, M. O.; Kistler, L. M.; Mouikis, C. G.; Rème, H.

    2017-09-01

    First coordinated observation of escaping heavy molecular ions in the Earth's inner magnetosphere and at the Moon. Quantifying the underlying escape mechanisms is important in order to understand the long-term (billion years scale) evolution of the atmospheric composition, and in particular the evolution of the N/O ratio, which is essential for habitability. Terrestrial heavy ions, transported to the Moon, suggest also that the Earth's atmosphere of billions of years ago may be preserved on the present-day lunar regolith.

  20. Molecular evolution and diversification of snake toxin genes, revealed by analysis of intron sequences.

    PubMed

    Fujimi, T J; Nakajyo, T; Nishimura, E; Ogura, E; Tsuchiya, T; Tamiya, T

    2003-08-14

    The genes encoding erabutoxin (short chain neurotoxin) isoforms (Ea, Eb, and Ec), LsIII (long chain neurotoxin) and a novel long chain neurotoxin pseudogene were cloned from a Laticauda semifasciata genomic library. Short and long chain neurotoxin genes were also cloned from the genome of Laticauda laticaudata, a closely related species of L. semifasciata, by PCR. A putative matrix attached region (MAR) sequence was found in the intron I of the LsIII gene. Comparative analysis of 11 structurally relevant snake toxin genes (three-finger-structure toxins) revealed the molecular evolution of these toxins. Three-finger-structure toxin genes diverged from a common ancestor through two types of evolutionary pathways (long and short types), early in the course of evolution. At a later stage of evolution in each gene, the accumulation of mutations in the exons, especially exon II, by accelerated evolution may have caused the increased diversification in their functions. It was also revealed that the putative MAR sequence found in the LsIII gene was integrated into the gene after the species-level divergence.

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