Life Sciences

Obstructive sleep apnea, immuno-inflammation, and atherosclerosis.

C.Arnaud , J.Baguet , P.Levy , J.Pepin , M.Dematteis


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Obstructive sleep apnea is a highly prevalent sleep disorder leading to cardiovascular and metabolic complications. OSA is also a multicomponent disorder, with intermittent hypoxia as the main trigger for the associated cardiovascular and metabolic alterations. Indeed, recurrent pharyngeal collapses during sleep lead to repetitive sequences of hypoxia-reoxygenation. This IH induces several consequences such as hemodynamic, hormonometabolic, oxidative, and immuno-inflammatory alterations that may interact and aggravate each other, resulting in artery changes, from adaptive to degenerative atherosclerotic remodeling. Atherosclerosis has been found in OSA patients free of other cardiovascular risk factors and is related to the severity of nocturnal hypoxia. Early stages of artery alteration, including functional and structural changes, have been evidenced in both OSA patients and rodents experimentally exposed to IH. Impaired vasoreactivity with endothelial dysfunction and/or increased vasoconstrictive responses due to sympathetic, endothelin, and renin-angiotensin systems have been reported and also contribute to vascular remodeling and inflammation. Oxidative stress, inflammation, and vascular remodeling can be directly triggered by IH, further aggravated by the OSA-associated hormonometabolic alterations, such as insulin resistance, dyslipidemia, and adipokine imbalance. As shown in OSA patients and in the animal model, genetic susceptibility, comorbidities , and life habits may aggravate atherosclerosis development or progression. The intimate molecular mechanisms are still largely unknown, and their understanding may contribute to delineate new targets for prevention strategies and/or development of new treatment of OSA-related atherosclerosis, especially in patients at risk for cardiovascular disease.

Key attributes to the disturbance response of montane cloud forest trees: shade tolerance, dispersal mode and the capacity to form a seed bank

F.J. , M.Equihua , V.J , I.Mendez-Ramirez , C.Fragoso


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Context Understanding the biological mechanisms related to plant response to disturbance is essential for predicting the changes in the structure of plant communities resulting from disturbance. Aims The aims of this study are to identify the regeneration traits linked to the response to disturbance of tree species of a montane cloud forest in order to define regeneration types and to explore whether disturbance intensity acts to select specific regeneration types that can colonize disturbed plots. Methods A theoretical model was developed and evaluated using structural equation modeling to link two latent variables: regeneration type and vulnerability to disturbance. We studied two plots that were subjected to different intensities of distur-bance and one plot of mature forest. Results Shade tolerance, dispersal mode, and the capacity to form a seed bank were the traits that determine regeneration type. There was a trend for re-sprouting capacity to be asso-ciated with the regeneration types dominant in disturbed plots. Regeneration types were differentially distributed among the sites. Conclusion There was evidence that disturbance intensity has a filtering effect on the colonization of disturbed plots. Species vulnerability to disturbance depends on specific combinations of regeneration traits. Structural equation modeling is useful for exploring plant response to disturbance using key parameters linked to plant persistence.

Transcriptome profiling in rat inbred strains and experimental cross reveals discrepant genetic architecture of genome-wide gene expression

D.Gauguier , P.J. , G.W. , K.Argoud , S.C. , R.H. , S.P. , A.C.Y. , C.Hue , S.Calderari , M.Bihoreau , J.Cazier , R.Mott


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To test the impact of genetic heterogeneity on cis-and trans-mediated mechanisms of gene expression regulation, we profiled the transcriptome of adipose tissue in 20 inbred congenic strains derived from diabetic Goto Kakizaki rats and BrownNorway controls, which contain well-defined blocks of genetic poly-morphisms, and in 123 genetically heterogeneous rats of an F2 offspring. Within each congenic we identified 731351 differentially expressed genes , only 7. 7% of which mapped within the congenic blocks, and which may be regulated in cis. The remainder localized outside the blocks, and therefore must be regulated in trans. Most trans-regulated genes exhibited approximately twofold expression changes, consistent with monoallelic expression. Altered biological pathways were replicated between congenic strains sharing blocks of genetic polymor-phisms, but polymorphisms at different loci also had redundant effects on transcription of common distant genes and pathways. We mapped 2735 expression quantitative trait loci in the F2 cross, including 26% predominantly cis-regulated genes, which validated DEGs in congenic strains. A hotspot of. 300 eQTL in a 10 cM region of chromosome 1 was enriched in DEGs in a congenic strain. However, many DEGs among GK, BN and congenic strains did not replicate as eQTL in F2 hybrids, demonstrating distinct mechanisms of gene expression when alleles segregate in an outbred population or are fixed homozygous across the entire genome or in short genomic regions. Our analysis provides conceptual advances in our understanding of the complex architecture of genome expression and pathway regulation, and suggests a prominent impact of epistasis and monoallelic expression on gene transcription.

Is Induced Abortion a Risk Factor in Subsequent Pregnancy?

Z.Marek , F.Klaus , B.Volker , V.Manfred , H.Wolfgang , S.Sebastian


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Objective: To determine whether a history of terminations of pregnancy influences subsequent pregnancies in terms of pregnancy risks, prematurity and neonatal biometrics. Patients and methods: Based on the perinatal statistics of eight German federal states, data of 247,593 primiparous women with singleton pregnancies born between 1998 and 2000 were analyzed. The control group consisted of primiparous women without previous induced abortions. Maternal age was adjusted for. Results: There was an overall trend towards an increased rate of preterm delivery at <= 36 weeks' gestation and early preterm delivery at <= 31 weeks' gestation in women who had previous pregnancy terminations. For the cohort of 28-30 years, the observed rates of prematurity in women with one and with >= 2 previous induced abortions were 7.8% and 8.5%, respectively, compared to 6.5% in the control population (P=0.015). Preceding terminations of pregnancy did not alter the rate of small-for-gestational-age newborns. Psychosocial stress and symptoms associated with prematurity such as cervical incompetence and vaginal bleeding before and after 28 weeks of gestation occurred more frequently in women with previous induced abortion compared to the control group (P<0.0001). Conclusion: The rate of preterm births increases with the number of preceding abortions. Similarly, symptoms associated with prematurity are more common. The rate of small-for-gestational-age newborns was not affected by preceding terminations of pregnancy.

Biochar is a growth-promoting alternative to peat moss for the inoculation of corn with a pseudomonad

M.Godowska , B.Husk , T.Schwinghamer , D.Smith


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AbstractPeat moss has been a standard carrier of inoculum for experimentation and in agriculture. Peat moss is, however, a non-renewable resource. Alternatively, biochar could serve as an inoculum carrier. Here, we tested the effect of biochar-based seed coatings as a carrier for the phosphorous-solubilizing Pseudomonas libanensis inoculum, on corn growth after soluble and insoluble P addition. The survival of P. libanensis was determined based on the measure of colony-forming units from samples of four inoculated guar gum-based biochar coatings and was compared to peat. Storage experiments were performed on inoculated biochars for 22weeks at 25C and on coated corn seeds for 16weeks at 4C. Seed coatings were prepared with inoculated and uninoculated biochars , and effects of these treatments are reported on indices of seed germination after 7days. A greenhouse experiment investigated the effects of the inoculated and uninoculated biochar seed coating on corn plants. The parameters measured from the greenhouse-grown corn plants were germination, fresh weight, dry weight, height, root length, basal stem diameter, leaf area, chlorophyll content, and tissue phosphorous. Our results show that corn plants grown from seeds coated with a biochar from hardwood feedstock are 2 to 10g heavier than controls and that controls are 4 to 26% shorter than the plants grown from biochar-coated seeds, where soluble phosphorous is applied. Moreover, corn seeds that were coated with a biochar produced from softwood feedstock germinated more quickly, based on the speed of germination index. Overall, we show that a biochar-based seed coating can benefit sustainable agriculture by carrying P. libanensis and enhancing the growth of corn, but according to parametric statistical tests, it does so without increasing the phosphorous content of the plants.

Chronic Intake of a Cafeteria Diet and Subsequent Abstinence. Sex-specific Effects on Gene Expression in the Mesolimbic Reward System

L.M. , H.J. , M.B. , O.Z. , W.A.


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Studies examining the impact of chronic palatable food intake on the mesolimbic reward system have been conducted almost exclusively in males. This study aimed to determine the effects of chronic intake of a palatable cafeteria diet and subsequent abstinence on fat mass, food intake and key gene expression of the mesolimbic reward system in both males and females. Albino Wistar rats were fed for 8 weeks on standard chow (Control, n=5 males, 5 females) or cafeteria diet (CD; n=16 males, 16 females). The cafeteria diet was then removed from a subset of CD rats for 72 h (CD-Withdrawal group, CD-W). The nucleus accumbens (NAc) was isolated and mRNA expression of tyrosine hydroxylase (TH), dopamine active transporter (DAT), D1 and D2 dopamine receptors, and μ-opioid receptor determined by qRT-PCR. Chronic cafeteria diet intake increased fat mass in all CD rats but body weight and chow intake were reduced during the period of cafeteria diet abstinence. TH mRNA was reduced in male CD and CD-W rats, but increased in female CD and CD-W rats. D1 mRNA was reduced in CD and CD-W females, but increased in CD males, compared to Controls. μ-opioid receptor expression was reduced in CD and CD-W males but not females. These data highlight the importance of investigating sex differences in the neurobiological response to palatable food intake and the need for future studies in this area to include both sexes.Zhi Yi Ong, Ayumi F. Wanasuria, Mark Z.P. Lin, Jennifer Hiscock, Beverly S. Muhlhausle

Bdnf Regulates the Expression and Traffic of NMDA Receptors in Cultured Hippocampal Neurons

P.Daniela , C.Ana , D.Carlos , C.Margarida , M.Carlos , C.Ricardo


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The neurotrophin BDNF regulates the activity-dependent modifications of synaptic strength in the CNS. Physiological and biochemical evidences implicate the NMDA glutamate receptor as one of the targets for BDNF modulation. In the present study, we investigated the effect of BDNF on the expression and plasma membrane abundance of NMDA receptor subunits in cultured hippocampal neurons. Acute stimulation of hippocampal neurons with BDNF differentially upregulated the protein levels of the NR1, NR2A and NR2B NMDA receptor subunits, by a mechanism sensitive to transcription and translation inhibitors. Accordingly, BDNF also increased the mRNA levels for NR1, NR2A and NR2B subunits. The neurotrophin NT3 also upregulated the protein levels of NR2A and NR2B subunits, but was without effect on the NR1 subunit. The amount of NR1, NR2A and NR2B proteins associated with the plasma membrane of hippocampal neurons was differentially increased by BDNF stimulation for 30 min or 24 h. The rapid upregulation of plasma membrane-associated NMDA receptor subunits was correlated with an increase in NMDA receptor activity. The results indicate that BDNF increases the abundance of NMDA receptors and their delivery to the plasma membrane, thereby upregulating receptor activity in cultured hippocampal neurons.http://www.sciencedirect.com/science/article/B6WNB-4N5TN7K-5/1/0ea25e5eae5132c7c4af4b86bd88a89
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