Identification of GIT1/Cat-1 as a substrate molecule of protein tyrosine phosphatase ζ/β by the yeast substrate-trapping system

We used a genetic method, the yeast substrate-trapping system, to identify substrates for protein tyrosine phosphatases ζ (PTPζ/RPTPβ). This method is based on the yeast two-hybrid system, with two essential modifications: conditional expression of protein tyrosine kinase v-src (active src) to tyrosine-phosphorylate the prey proteins and screening by using a substrate-trap mutant of PTPζ (PTPζ-D1902A) as bait. By using this system, several substrate candidates for PTPζ were isolated. Among them, GIT1/Cat-1 (G protein-coupled receptor kinase-interactor 1/Cool-associated, tyrosine-phosphorylated 1) was examined further. GIT1/Cat-1 bound to PTPζ-D1902A dependent on the substrate tyrosine phosphorylation. Tyrosine-phosphorylated GIT1/Cat-1 was dephosphorylated by PTPζ in vitro. Immunoprecipitation experiments indicated that PTPζ-D1902A and GIT1/Cat-1 form a stable complex also in mammalian cells. Immunohistochemical analyses revealed that PTPζ and GIT1/Cat-1 were colocalized in the processes of pyramidal cells in the hippocampus and neocortex in rat brain. Subcellular colocalization was further verified in the growth cones of mossy fibers from pontine explants and in the ruffling membranes and processes of B103 neuroblastoma cells. Moreover, pleiotrophin, a ligand for PTPζ, increased tyrosine phosphorylation of GIT1/Cat-1 in B103 cells. All these results indicate that GIT1/Cat-1 is a substrate molecule of PTPζ.

Maternal effort mediates the prevalence of trypanosomes in the offspring of a passerine bird.

The relationships between parental effort, offspring growth, and offspring blood parasitemias are poorly known. We examined the effect of parental effort on offspring size and prevalence of trypanosomes in peripheral blood of nestling Pied Flycatchers Ficedula hypoleuca aged 13 days. Trypanosome infections were likely to be shared by siblings, indicating the role of a common environment and/or shared genes in the susceptibility to infection. Broods infected by trypanosomes had reduced growth, but this was due to decreased parental, especially maternal, energy expenditure in broods with nestlings infected by trypanosomes. There was no association between parental infection with trypanosomes and both their energy expenditure and the infection of their broods. Under stressful conditions caused by low maternal energy expenditure, the immune response of nestlings during growth was probably impaired, in a way analogous to the relapses of blood parasitemias with reproductive effort in breeding animals.

Conformational trapping in a membrane environment: a regulatory mechanism for protein activity?

Functional regulation of proteins is central to living organisms. Here it is shown that a nonfunctional conformational state of a polypeptide can be kinetically trapped in a lipid bilayer environment. This state is a metastable structure that is stable for weeks just above the phase transition temperature of the lipid. When the samples are incubated for several days at 68 degrees C, 50% of the trapped conformation converts to the minimum-energy functional state. This result suggests the possibility that another mechanism for functional regulation of protein activity may be available for membrane proteins: that cells may insert proteins into membranes in inactive states pending the biological demand for protein function.

Trapping of branched DNA in microfabricated structures.

We have observed electrostatic trapping of tribranched DNA molecules undergoing electrophoresis in a microfabricated pseudo-two-dimensional array of posts. Trapping occurs in a unique transport regimen in which the electrophoretic mobility is extremely sensitive to polymer topology. The arrest of branched polymers is explained by considering their center-of-mass motion; in certain conformations, owing to the constraints imposed by the obstacles a molecule cannot advance without the center of mass first moving a short distance backwards. The depth of the resulting local potential well can be much greater than the thermal energy so that escape of an immobilized molecule can be extremely slow. We summarize the expected behavior of the mobility as a function of field strength and topology and point out that the microfabricated arrays are highly suitable for detecting an extremely small number of branched molecules in a very large population of linear molecules.

The Use of the Rey 15-Item Test and Recognition Trial to Evaluate Suboptimal Effort in Neuropsychological Assessment with a Pediatric Mild TBI Sample

The utilization of symptom validity tests (SVTs) in pediatric assessment is receiving increasing empirical support. The Rey 15-Item Test (FIT) is an SVT commonly used in adult assessment, with limited research in pediatric populations. Given that FIT classification statistics across studies to date have been quite variable, Boone, Salazar, Lu, Warner-Chacon, and Razani (2002) developed a recognition trial to use with the original measure to enhance accuracy. The current study aims to assess the utility of the FIT and recognition trial in a pediatric mild traumatic brain injury (TBI) sample (N = 112; M = 14.6 years), in which a suboptimal effort base rate of 17% has been previously established (Kirkwood & Kirk, 2010). All participants were administered the FIT as part of an abbreviated neuropsychological evaluation; failure on the Medical Symptom Validity Test (MSVT) was used as the criterion for suspect effort. The traditional adult cut-off score of(99%), but poor sensitivity (6%). When the recognition trial was also utilized, a combination score of(sensitivity = 64%, specificity = 93%). Results indicate that the FIT with recognition trial may be useful in the assessment of pediatric suboptimal effort, at least among relatively high functioning children following mild TBI.

Avaliação da musculatura inspiratória e expiratória na doença pulmonar obstrutiva crônica leve e grave comparada aos indivíduos saudáveis

Introdução: A DPOC é uma doença respiratória prevenível e tratável, caracterizada por limitação persistente ao fluxo aéreo, hiperinsuflação e aprisionamento aéreo. A dispneia e a intolerância aos esforços, decorrentes destas alterações fisiopatológicas sofre influência de vários fatores. Dentre estes, o recrutamento e a sobrecarga imposta aos músculos inspiratórios e expiratórios são de fundamental importância, porém a participação destes ainda não foi completamente elucidada em diferentes gravidades da doença. Objetivos: O objetivo principal deste estudo foi avaliar a mecânica ventilatória, e o grau de recrutamento da musculatura inspiratória e expiratória na DPOC leve e grave, na condição de repouso e durante um teste máximo de exercício, comparado a um grupo de indivíduos saudáveis. Metodologia: Trata-se de um estudo transversal envolvendo 36 indivíduos, sendo 24 pacientes portadores de DPOC e 12 voluntários sadios. As avaliações foram divididas em 2 visitas. No D1, foram realizadas uma avaliação clínica, avaliação de dispneia (mMRC) e de qualidade de vida (SGRQ), além da prova de função pulmonar completa. Na 2ª visita, realizada com intervalo de 1 semana, foram avaliadas: as pressões respiratórias máximas estáticas por meio de métodos volitivos (PImax, PEmax, SNIP, Pes sniff, Pga sniff e Pdi sniff) e não volitivos (Twitch cervical bilateral e T10); avaliação da sincronia toracoabdominal por pletismografia de indutância; avaliação do recrutamento dos músculos inspiratórios e expiratórios ao repouso pela eletromiografia de superfície; e, posteriormente, um teste de exercício cardiopulmonar incremental para estudo de todas essas variáveis no esforço. Resultados: Foram avaliados 24 pacientes (12 leves e 12 graves) e 12 indivíduos saudáveis da mesma faixa etária. A maioria dos pacientes apresentava comprometimento significativo da qualidade de vida e os pacientes do grupo grave eram mais sintomáticos. A função pulmonar encontrava-se alterada na maioria dos pacientes. Destes, 79,2% apresentavam aprisionamento aéreo e 70,8% tinham redução da DLCO. Tais alterações foram semelhantes nos 2 grupos de pacientes. A força muscular estática medida por métodos volitivos e não volitivos estava reduzida nos 2 grupos e mostrou relação com o VEF1. No exercício, a dispneia foi o principal motivo para interrupção do teste em 70% dos pacientes. A HD esteve presente em 87,5% dos pacientes. O comportamento das pressões respiratórias foi significativamente diferente entre os 3 grupos. Os pacientes com DPOC apresentaram maior atividade diafragmática (Pdi) comparado aos controles e a participação da musculatura expiratória também foi maior neste grupo, principalmente nos graves. Apesar disso, os pacientes com DPOC apresentaram uma eficiência mecânica reduzida, ou seja, esse incremento da força muscular foi insuficiente para manter uma ventilação adequada para uma determinada carga. Com o aumento da demanda ventilatória, houve recrutamento precoce e progressivo dos músculos inspiratórios e expiratórios durante o exercício. O trabalho resistivo e o expiratório foram significativamente diferentes entre os controles e os pacientes com DPOC desde o início do exercício. Como consequência destas alterações, a intensidade da dispneia durante o TECP foi maior nos pacientes com DPOC (leve e grave) para a mesma carga e mesma ventilação-minuto (VE), quando comparada aos indivíduos do grupo-controle. Conclusões: O conjunto destes achados demonstra que o comprometimento dos músculos inspiratórios e expiratórios contribuiu significativamente para a dispneia e a intolerância ao exercício tanto no DPOC leve quanto no DPOC grave. E que este comprometimento pode não ser detectado com os testes máximos de força ao repouso

Utilization of ADR Concepts to Bridge the Gap Between the Extractive Industry and Environmental Interests: An Anticipatory Cooperative Effort (ACE)

The extractive industry, more than any other sector of the economy, often finds itself mired in conflicts with various environmental and community interests. As traditional legal avenues of resolution gave way to the collaborative ideas of alternative dispute resolution, the outcomes, especially the relational outcomes, were less than desirable. This capstone project proposes that an Anticipatory Cooperative Effort (ACE) can help to bridge the gap between industry and environmental interests by encouraging a pro-active and pre-emptive engagement. The point of the ACE concept is not that it defines a new set of principles so much as it repositions where established ADR principles are entertained.

Response of Catch-Per-Unit-Effort to Spatial and Environmental Factors: an Exploratory Data Analysis Using Generalized Additive Models

Understanding spatial distributions and how environmental conditions influence catch-per-unit-effort (CPUE) is important for increased fishing efficiency and sustainable fisheries management. This study investigated the relationship between CPUE, spatial factors, temperature, and depth using generalized additive models. Combinations of factors, and not one single factor, were frequently included in the best model. Parameters which best described CPUE varied by geographic region. The amount of variance, or deviance, explained by the best models ranged from a low of 29% (halibut, Charlotte region) to a high of 94% (sablefish, Charlotte region). Depth, latitude, and longitude influenced most species in several regions. On the broad geographic scale, depth was associated with CPUE for every species, except dogfish. Latitude and longitude influenced most species, except halibut (Areas 4 A/D), sablefish, and cod. Temperature was important for describing distributions of halibut in Alaska, arrowtooth flounder in British Columbia, dogfish, Alaska skate, and Aleutian skate. The species-habitat relationships revealed in this study can be used to create improved fishing and management strategies.