lincRNAs act in the circuitry controlling pluripotency and differentiation

Although thousands of large intergenic non-coding RNAs (lincRNAs) have been identified in mammals, few have been functionally characterized, leading to debate about their biological role. To address this, we performed loss-of-function studies on most lincRNAs expressed in mouse embryonic stem (ES) cells and characterized the effects on gene expression. Here we show that knockdown of lincRNAs has major consequences on gene expression patterns, comparable to knockdown of well-known ES cell regulators. Notably, lincRNAs primarily affect gene expression in trans. Knockdown of dozens of lincRNAs causes either exit from the pluripotent state or upregulation of lineage commitment programs. We integrate lincRNAs into the molecular circuitry of ES cells and show that lincRNA genes are regulated by key transcription factors and that lincRNA transcripts bind to multiple chromatin regulatory proteins to affect shared gene expression programs. Together, the results demonstrate that lincRNAs have key roles in the circuitry controlling ES cell state.Broad InstituteHarvard UniversityNational Human Genome Research Institute (U.S.)Merkin Family Foundation for Stem Cell Researc

Aspects of astrocyte energy metabolism, amino acid neurotransmitter homoeostasis and metabolic compartmentation

Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy-generating pathways and amino acid homoeostasis. A discussion of the impact that uptake of neurotransmitter glutamate may have on these pathways is included along with a section on metabolic compartmentation

Experimental Ehrlichia canis infection changes acute-phase proteins

Early diagnosis of canine ehrlichiosis favors prompt institution of treatment and improves the prognosis for the animal, since this disease causes mortality among dogs. Studies have shown that determining the concentration of acute-phase proteins (APPs) may contribute towards early detection of disease and aid in predicting the prognosis. This study aimed to evaluate the APP profile in dogs experimentally infected with Ehrlichia canis, at the start of the infection and after treatment. It also investigated whether any correlation between APP levels and the clinical and laboratory alterations over the course of the disease would be possible. The results obtained showed abnormal levels of all the APPs on the third day after infection (D3), with the highest levels being reached on D18, with the exception of ceruloplasmin and acid glycoprotein, which presented their peaks on D6 and D12 respectively. We concluded that assessment of APP levels could contribute towards establishing an early diagnosis of canine ehrlichiosis, particularly regarding acid glycoprotein and ceruloplasmin, since these proteins were detected at increased levels even before the onset of clinical and laboratory findings of the disease.O diagnóstico precoce da erliquiose canina favorece a pronta instituição do tratamento e melhora o prognóstico do animal, pois se trata de uma doença de alta mortalidade em cães. Estudos têm apontado que a determinação da concentração de proteínas de fase aguda (PFA) pode contribuir para detecção precoce de doenças e auxiliar na predição do prognóstico. O presente estudo objetivou avaliar o perfil de proteínas de fase aguda (PFA) em cães experimentalmente infectados com Ehrlichia canis, no início da infecção e após o tratamento. Além disso, se seria possível associá-las com as alterações clínico-laboratoriais durante o curso da doença. Os resultados obtidos evidenciaram que todas as PFA estudadas alteraram suas concentrações em D3 (dia 3), comparadas ao D0, atingindo concentrações máximas em D18, com exceção da ceruloplasmina e da glicoproteína ácida, cujos picos foram observados em D6 e D12, respectivamente. Concluímos que a avaliação das concentrações de PFA poderiam contribuir para o diagnóstico precoce da erliquiose canina, principalmente com relação à ceruloplasmina e glicoproteína ácida, pois seus aumentos foram anteriores ao aparecimento dos sinais clínicos e das alterações laboratoriais da doença

Identification of Host Genes Involved in Geminivirus Infection Using a Reverse Genetics Approach

Geminiviruses, like all viruses, rely on the host cell machinery to establish a successful infection, but the identity and function of these required host proteins remain largely unknown. Tomato yellow leaf curl Sardinia virus (TYLCSV), a monopartite geminivirus, is one of the causal agents of the devastating Tomato yellow leaf curl disease (TYLCD). The transgenic 2IRGFP N. benthamiana plants, used in combination with Virus Induced Gene Silencing (VIGS), entail an important potential as a tool in reverse genetics studies to identify host factors involved in TYLCSV infection. Using these transgenic plants, we have made an accurate description of the evolution of TYLCSV replication in the host in both space and time. Moreover, we have determined that TYLCSV and Tobacco rattle virus (TRV) do not dramatically influence each other when co-infected in N. benthamiana, what makes the use of TRV-induced gene silencing in combination with TYLCSV for reverse genetic studies feasible. Finally, we have tested the effect of silencing candidate host genes on TYLCSV infection, identifying eighteen genes potentially involved in this process, fifteen of which had never been implicated in geminiviral infections before. Seven of the analyzed genes have a potential anti-viral effect, whereas the expression of the other eleven is required for a full infection. Interestingly, almost half of the genes altering TYLCSV infection play a role in postranslational modifications. Therefore, our results provide new insights into the molecular mechanisms underlying geminivirus infections, and at the same time reveal the 2IRGFP/VIGS system as a powerful tool for functional reverse genetics studies

Molecular and serological detection of tick-borne pathogens in dogs from an area endemic for Leishmania infantumin Mato Grosso do Sul, Brazil

Patógenos transmitidos por carrapatos atingem uma variedade de hospedeiros vertebrados. Para identificar os agentes patogênicos transmitidos por carrapatos entre cães soropositivos para Leishmania infantum no município Campo Grande-MS, foi realizado um estudo sorológico e molecular para a detecção de Ehrlichia canis, Anaplasma platys e Babesia vogeli em 60 amostras de soro e baço, respectivamente. Adicionalmente, foi realizado o diagnóstico confirmatório de L. infantum por meio de técnicas sorológicas e moleculares. Também foi realizado o alinhamento e análise filogenética das sequências para indicar a identidade das espécies de parasitas que infectam esses animais. Anticorpos IgG anti-Ehrlichia spp., anti-B. vogeli e anti-L. infantum foram detectados em 39 (65%), 49 (81,6%) e 60 (100%) dos cães amostrados, respectivamente. Vinte e sete (45%), cinquenta e quatro (90%), cinquenta e três (88,3%), dois (3,3%) e um (1,6%) cães mostraram-se positivos na PCR para E. canis, Leishmania spp., Leishmania donovani complex, Babesia sp. e Anaplasma sp., respectivamente. Após o seqüenciamento, os amplicons mostraram 99% de similaridade com isolados de E. canis, B. vogeli e A. platys e Leishmania chagasi. Os resultados deste estudo indicaram que os cães soropositivos para L. infantum de Campo Grande, MS, são expostos a vários agentes transmitidos por carrapatos, e, portanto, devem ser incluídos no diagnóstico diferencial em cães com suspeita clínica de leishmaniose.Tick-borne pathogens affect a wide range of vertebrate hosts. To identify tick-borne pathogens among dogs from Campo Grande, MS, Brazil testing seropositive for Leishmania infantum (syn. L. chagasi), a serological and molecular study was conducted to detect Ehrlichia canis, Anaplasma platys and Babesia vogeli in 60 serum and spleen samples. A confirmatory diagnosis of L. infantum based on serological and molecular assays was also performed, as was sequence alignment and phylogenetic analysis to assess the identity of the parasite species infecting these animals. IgG antibodies to Ehrlichia spp., B. vogeli and L. infantum were found, respectively, in 39 (65%), 49 (81.6%) and 60 (100%) of the sampled dogs. Twenty-seven (45%), fifty-four (90%), fifty-three (88.3%), two (3.3%) and one (1.6%) dog were positive, respectively, for E. canis, Leishmania spp., Leishmania donovani complex, Babesia sp. and Anaplasma sp. in PCR assays. After sequencing, the amplicons showed 99% of identity with E. canis, B. vogeli, A. platys and Leishmania chagasi isolates. The findings of this study indicate that L. infantum-seropositive dogs from Campo Grande are exposed to multiple tick-borne pathogens, which should therefore be included in the differential diagnosis of dogs with clinical suspicion of leishmaniasis.Universidade Estadual Paulista - Unesp Faculdade de Ciencias Agrarias e Veterinarias - FCAVCampo GrandeUniversidade Estadual Paulista - Unesp Faculdade de Ciencias Agrarias e Veterinarias - FCA

Dynamical structure of center-of-pressure trajectories in patients recovering from stroke

Contains fulltext : 50308.pdf (publisher's version ) (Closed access)In a recent study, De Haart et al. (Arch Phys Med Rehabil 85:886-895, 2004) investigated the recovery of balance in stroke patients using traditional analyses of center-of-pressure (COP) trajectories to assess the effects of health status, rehabilitation, and task conditions like standing with eyes open or closed and standing while performing a cognitive dual task. To unravel the underlying control processes, we reanalyzed these data in terms of stochastic dynamics using more advanced analyses. Dimensionality, local stability, regularity, and scaling behavior of COP trajectories were determined and compared with shuffled and phase-randomized surrogate data. The presence of long-range correlations discarded the possibility that the COP trajectories were purely random. Compared to the healthy controls, the COP trajectories of the stroke patients were characterized by increased dimensionality and instability, but greater regularity in the frontal plane. These findings were taken to imply that the stroke patients actively (i.e., cognitively) coped with the stroke-induced impairment of posture, as reflected in the increased regularity and decreased local stability, by recruiting additional control processes (i.e., more degrees of freedom) and/or by tightening the present control structure while releasing non-essential degrees of freedom from postural control. In the course of rehabilitation, dimensionality stayed fairly constant, whereas local stability increased and regularity decreased. The progressively less regular COP trajectories were interpreted to indicate a reduction of cognitive involvement in postural control as recovery from stroke progressed. Consistent with this interpretation, the dual task condition resulted in less regular COP trajectories of greater dimensionality, reflecting a task-related decrease of active, cognitive contributions to postural control. In comparison with conventional posturography, our results show a clear surplus value of dynamical measures in studying postural control