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  • Differential Vulnerability of Outer and Inner Hair Cells during and after Oxygen-Glucose Deprivation in Organotypic Cultures of Newborn Rats
    Differential Vulnerability of Outer and Inner Hair Cells during and after Oxygen-Glucose Deprivation in Organotypic Cultures of Newborn Rats

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    Document Overview:
    Ischemia can contribute to the inner ear pathology and hearing loss. To determine the susceptibility of inner and outer hair cells (IHCs/OHCs) to ischemic and post-ischemic period, we used organotypic cultures of the organ of Corti isolated from P3 rats as an in vitro model of inner ear ischemia (oxygen-glucose deprivation, OGD). We identified the hair cells (HCs) by phalloidin staining. The cells with damaged cellular membrane integrity were identified by propidium iodide (PI)-exclusion assay. The cells with fragmented chromosomal DNA were detected by TUNEL assay. Organotypic cultures were subjected to a mild (3 h duration) or severe (4 h duration) OGD, followed by a recovery period of 21 h and 20 h, respectively. Mild OGD induced a loss of 10-20 % HCs, whereas severe OGD induced loss of 35 % HCs. We confirmed that OHCs are less vulnerable to OGD than IHCs. Of all missing OHCs, 80-90 % was lost during the OGD period and 10-20 % during the recovery period. In contrast, the loss of IHCs was equal during both experimental periods. The OGD period was mainly associated with PI-positive nuclei. TUNEL-positive nuclei were a minor fraction during the OGD period and increased during the recovery period, indicating the progression of DNA fragmentation. Our results implicate a differential susceptibility of IHCs and OHCs during and after ischemia-like insult, which may be of therapeutic consequence. [PUBLICATION ABSTRACT]
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  • Effect of Chronic Nifedipine Treatment on Blood Pressure and Adrenergic Responses of Isolated Mesenteric Artery in Young Rats with Developing Spontaneous Hypertension
    Effect of Chronic Nifedipine Treatment on Blood Pressure and Adrenergic Responses of Isolated Mesenteric Artery in Young Rats with Developing Spontaneous Hypertension

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    It is documented that in chronic hypertensive state there is an increased vasodepressor response to calcium channel antagonists such as the dihydropyridine derivate nifedipine. This effect is generally proportional to initial blood pressure as was demonstrated in several models of experimental hypertension. In the present study we investigated the effect of chronic nifedipine treatment on the development of cardiovascular system in young spontaneously hypertensive rats (SHR) in order to evaluate whether it could prevent the abnormalities leading to hypertensive state. Four- and eight-week-old rats were treated with nifedipine (50 mg/kg/day) for 4 weeks. Blood pressure of nifedipine-treated SHR remained at the initial level in contrast to their untreated controls where it continued to increase. In both age groups, chronic nifedipine administration reduced neurogenic contractions of isolated superior mesenteric artery, but did not significantly affect the dose-response curve to exogenous noradrenaline in 8-week-old rats. In contrast, maximum response to noradrenaline was significantly attenuated in mesenteric artery of 12-week-old nifedipine-treated SHR. We can presume that the antihypertensive effect of nifedipine is similar in both stages of spontaneous hypertension development, but the mechanisms involved might be different. It seems that chronic reduction of calcium influx during the rapid phase of pathological blood pressure increase in SHR may eliminate the effect of enhanced sympathetic tone, which may have unfavorable consequences on cardiovascular structure and function. [PUBLICATION ABSTRACT]
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  • Snf1p Regulates Gcn5p Transcriptional Activity by Antagonizing Spt3p
    Snf1p Regulates Gcn5p Transcriptional Activity by Antagonizing Spt3p

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    The budding yeast Gcn5p is a prototypic histone acetyltransferase controlling transcription of diverse genes. Here we show that Gcn5p is itself regulated by Snf1p and Spt3p. Snf1p likely controls Gcn5p via direct interaction. Mutating four residues in the Gcn5p catalytic domain, T203, S204, T211, and Y212 (TSTY), phenocopies snf1 null cells, including Gcn5p hypophosphorylation, hypoacetylation at the HIS3 promoter, and transcriptional defects of the HIS3 gene. However, overexpressing Snf1p suppresses the above phenotypes associated with the phosphodeficient TSTY mutant, suggesting that it is the interaction with Snf1p important for Gcn5p to activate HIS3. A likely mechanism by which Snf1p potentiates Gcn5p function is to antagonize Spt3p, because the HIS3 expression defects caused by snf1 knockout, or by the TSTY gcn5 mutations, can be suppressed by deleting SPT3. In vitro, Spt3p binds Gcn5p, but the interaction is drastically enhanced by the TSTY mutations, indicating that a stabilized Spt3p-Gcn5p interaction may be an underlying cause for the aforementioned HIS3 transcriptional defects. These results suggest that Gcn5p is a target regulated by the competing actions of Snf1p and Spt3p. [PUBLICATION ABSTRACT]
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  • The Impact of Whole Genome Sequencing on Model System Genetics: Get Ready for the Ride
    The Impact of Whole Genome Sequencing on Model System Genetics: Get Ready for the Ride

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    Much of our understanding of how organisms develop and function is derived from the extraordinarily powerful, classic approach of screening for mutant organisms in which a specific biological process is disrupted. Reaping the fruits of such forward genetic screens in metazoan model systems like Drosophila, Caenorhabditis elegans, or zebrafish traditionally involves time-consuming positional cloning strategies that result in the identification of the mutant locus. Whole genome sequencing (WGS) has begun to provide an effective alternative to this approach through direct pinpointing of the molecular lesion in a mutated strain isolated from a genetic screen. Apart from significantly altering the pace and costs of genetic analysis, WGS also provides new perspectives on solving genetic problems that are difficult to tackle with conventional approaches, such as identifying the molecular basis of multigenic and complex traits. [PUBLICATION ABSTRACT]
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  • Histone H3K4 and K36 Methylation, Chd1 and Rpd3S Oppose the Functions of Saccharomyces cerevisiae Spt4-Spt5 in Transcription
    Histone H3K4 and K36 Methylation, Chd1 and Rpd3S Oppose the Functions of Saccharomyces cerevisiae Spt4-Spt5 in Transcription

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    Spt4-Spt5, a general transcription elongation factor for RNA polymerase II, also has roles in chromatin regulation. However, the relationships between these functions are not clear. Previously, we isolated suppressors of a Saccharomyces cerevisiae spt5 mutation in genes encoding members of the Paf1 complex, which regulates several cotranscriptional histone modifications, and Chd1, a chromatin remodeling enzyme. Here, we show that this suppression of spt5 can result from loss of histone H3 lysines 4 or 36 methylation, or reduced recruitment of Chd1 or the Rpd3S complex. These spt5 suppressors also rescue the synthetic growth defects observed in spt5 mutants that also lack elongation factor TFIIS. Using a FLO8 reporter gene, we found that a chd1 mutation caused cryptic initiation of transcription. We further observed enhancement of cryptic initiation in chd1 isw1 mutants and increased histone acetylation in a chd1 mutant. We suggest that, as previously proposed for H3 lysine 36 methylation and the Rpd3S complex, H3 lysine 4 methylation and Chd1 function to maintain normal chromatin structures over transcribed genes, and that one function of Spt4-Spt5 is to help RNA polymerase II overcome the repressive effects of these histone modifications and chromatin regulators on transcription. [PUBLICATION ABSTRACT]
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  • BRIDGING THE GAP BETWEEN FOOD AND HEALTH
    BRIDGING THE GAP BETWEEN FOOD AND HEALTH

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    Many an executive has strutted around the boardroom stating that the "next big thing in the food industry is health." So, as a result, more and more products proffering and claiming health benefits have been launched into the market and now grace our supermarket shelves. "Functional" has become a food sector buzzword and a Holy Grail for the major players in the F&B industry. Yet, there's a problem.
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  • WEIGHING UP WEIGHT MANAGEMENT
    WEIGHING UP WEIGHT MANAGEMENT

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    Weight management continues to be an ongoing major consumer issue, whether the focus is on dieting to lose weight or managing weight and muscle mass during an intensive exercise regime. Our motives also vary; it's sometimes about appearance, fitness levels and/or managing or even preventing serious health Issues. But the eternal questions remain the same: why Is some weight loss healthy and some less so?
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  • The Rim101p/PacC Pathway and Alkaline pH Regulate Pattern Formation in Yeast Colonies
    The Rim101p/PacC Pathway and Alkaline pH Regulate Pattern Formation in Yeast Colonies

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    Multicellular organisms utilize cell-to-cell signals to build patterns of cell types within embryos, but the ability of fungi to form organized communities has been largely unexplored. Here we report that colonies of the yeast Saccharomyces cerevisiae formed sharply divided layers of sporulating and nonsporulating cells. Sporulation initiated in the colony's interior, and this region expanded upward as the colony matured. Two key activators of sporulation, IME1 and IME2, were initially transcribed in overlapping regions of the colony, and this overlap corresponded to the initial sporulation region. The development of colony sporulation patterns depended on cell-to-cell signals, as demonstrated by chimeric colonies, which contain a mixture of two strains. One such signal is alkaline pH, mediated through the Rim101p/PacC pathway. Meiotic-arrest mutants that increased alkali production stimulated expression of an early meiotic gene in neighboring cells, whereas a mutant that decreased alkali production (cit1Δ) decreased this expression. Addition of alkali to colonies accelerated the expansion of the interior region of sporulation, whereas inactivation of the Rim101p pathway inhibited this expansion. Thus, the Rim101 pathway mediates colony patterning by responding to cell-to-cell pH signals. Cell-to-cell signals coupled with nutrient gradients may allow efficient spore formation and spore dispersal in natural environments. [PUBLICATION ABSTRACT]
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  • Late Effect of Early Hypoxic Disturbance in the Rat Heart: Gender Differences
    Late Effect of Early Hypoxic Disturbance in the Rat Heart: Gender Differences

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    Perinatal hypoxemia may have serious long-term effects on the adult cardiovascular system and may lead to sex-dependent changes in cardiac tolerance to acute ischemia in adult life. The aim of the study was to answer the question whether gonadectomy of the male and female rats in the early phase of ontogenetic development affects the late effect of perinatal hypoxia. Pregnant Wistar rats were placed into a normobaric hypoxic chamber (12 % O2) 7 days before the expected date of delivery. Newborn pups were kept in the chamber with their mothers for another 5 days after birth. After hypoxic exposure all animals were kept for 3 months in room air. Some of the pups were gonadectomized right after removal from the hypoxic chamber. Ventricular arrhythmias were assessed on isolated perfused hearts. Castration did not influence arrhythmogenesis in the adult normoxic or perinatally hypoxic female hearts. Nevertheless, the number of arrhythmias was decreased in perinatally hypoxic gonadectomized males. In conclusion, we have shown that perinatal normobaric hypoxia increased cardiac tolerance to acute ischemia in adult male rats; however, it had no late effect in females. Gonadectomy did not affect arrhythmogenesis in both normoxic and hypoxic female hearts, whereas in males significantly decreased the number of arrhythmias. [PUBLICATION ABSTRACT]
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  • Adenosine A^sub 1^, A^sub 2a^, A^sub 2b^, and A^sub 3^ Receptors in Hematopoiesis. 1. Expression of Receptor mRNA in Four Mouse Hematopoietic Precursor Cells
    Adenosine A^sub 1^, A^sub 2a^, A^sub 2b^, and A^sub 3^ Receptors in Hematopoiesis. 1. Expression of Receptor mRNA in Four Mouse Hematopoietic Precursor Cells

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    Four mouse bone marrow or thymus cell populations, namely granulopoietic/monocytopoietic, erythropoietic, B-lymphopoietic, and T-lymphopoietic precursor cells have been assayed by RTPCR technique for the presence and relative amounts of adenosine A^sub 1^, A^sub 2a^, A^sub 2b^, and A^sub 3^ receptor mRNA. It has been found that (i) all four populations studied express all four adenosine receptor subtypes, (ii) the A^sub 1^ receptor is the least expressed in all populations studied, (iii) the A^sub 3^ receptor is markedly expressed in the populations of granulopoietic/monocytopoietic and erythropoietic cells, (iv) the A^sub 2a^ receptor is markedly expressed in the populations of B-lymphopoietic and T-lymphopoietic cells, and v) the A^sub 2b^ receptor does not predominate in any of the precursor cells studied. Our data offer a new possibility for the assessment of the readiness of these cells to respond, by receptor-mediated mechanisms, to adenosine or its analogs present in the tissues as a result of endogenous processes and/or following their administration. [PUBLICATION ABSTRACT]
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  • Adenosine A^sub 1^, A^sub 2a^, A^sub 2b^, and A^sub 3^ Receptors in Hematopoiesis. 2. Expression of Receptor mRNA in Resting and Lipopolysaccharide-Activated Mouse RAW 264.7 Macrophages
    Adenosine A^sub 1^, A^sub 2a^, A^sub 2b^, and A^sub 3^ Receptors in Hematopoiesis. 2. Expression of Receptor mRNA in Resting and Lipopolysaccharide-Activated Mouse RAW 264.7 Macrophages

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    Expression of mRNA for adenosine receptor subtypes A^sub 1^, A^sub 2a^, A^sub 2b^, and A^sub 3^ in normal and lipopolysaccharide (LPS)-activated murine RAW 264.7 macrophages has been investigated using the method of quantitative real-time polymerase chain reaction. The results have shown a very low, unquantifiable expression of adenosine A^sub 1^ receptor mRNA in both normal and LPS-activated macrophages. The other three adenosine receptor mRNAs have been found to be expressed at various but always quantifiable levels. Activation of the macrophages by LPS induced upregulation of the expression of adenosine receptor A^sub 2a^ and A^sub 2b^ mRNA, whereas the expression of adenosine receptor A^sub 3^ mRNA was downregulated. Unstimulated macrophages exhibited a high expression of the A^sub 2b^ adenosine receptor mRNA. The findings are discussed from the point of view of the antiinflammatory and hematopoiesis-stimulating roles of the adenosine receptor signaling. [PUBLICATION ABSTRACT]
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  • Constraints on clade ages from fossil outgroups
    Constraints on clade ages from fossil outgroups

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    This paper presents a method for constraining the age of a clade with the ages of the earliest fossil specimens in that clade's outgroups. Given a sufficiently deep, robust, well-resolved, and stratigraphically consistent cladogram, this method can yield useful age constraints even in the absence of specific information about the fossil preservation and recovery rates of individual taxa. The algorithm is applied to simulated data sets to demonstrate that this method can yield robust constraints of clade ages if there are sufficient fossil outgroups available and if there is a finite chance that additional outgroups may be discovered in the future. Finally, the technique is applied to actual fossil data to explore the origin of modern placental mammals. Using data from recently published cladograms, this method indicates that if all Mesozoic eutherians are regarded as outgroups of Placentalia, then the last common ancestor of modern placental mammals and their Cenozoic allies lived between 65 and 88-98 million years ago, depending on the assumed cladogram and the number of outgroups included in the analysis. [PUBLICATION ABSTRACT]
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  • Ethical BioTrade Awards for Biodiversity
    Ethical BioTrade Awards for Biodiversity

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    To celebrate the United Nations 2010 International Year of Biodiversity, the Union for Ethical BioTrade and Food ingrethents Europe Is proud to announce the first Ethical BioTrade Awards for Biodiversity. The awards were announced In Frankfurt, during FiE, and will be presented next year in Madrid at Fi Europe's sister show, Health Ingrethents Europe 201 0.
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  • On the Classification of Epistatic Interactions
    On the Classification of Epistatic Interactions

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    Modern genomewide association studies are characterized by the problem of "missing heritability." Epistasis, or genetic interaction, has been suggested as a possible explanation for the relatively small contribution of single significant associations to the fraction of variance explained. Of particular concern to investigators of genetic interactions is how to best represent and define epistasis. Previous studies have found that the use of different quantitative definitions for genetic interaction can lead to different conclusions when constructing genetic interaction networks and when addressing evolutionary questions. We suggest that instead, multiple representations of epistasis, or epistatic "subtypes," may be valid within a given system. Selecting among these epistatic subtypes may provide additional insight into the biological and functional relationships among pairs of genes. In this study, we propose maximum-likelihood and model selection methods in a hypothesis-testing framework to choose epistatic subtypes that best represent functional relationships for pairs of genes on the basis of fitness data from both single and double mutants in haploid systems. We gauge the performance of our method with extensive simulations under various interaction scenarios. Our approach performs reasonably well in detecting the most likely epistatic subtype for pairs of genes, as well as in reducing bias when estimating the epistatic parameter (ε). We apply our approach to two available data sets from yeast (Saccharomyces cerevisiae) and demonstrate through overlap of our identified epistatic pairs with experimentally verified interactions and functional links that our results are likely of biological significance in understanding interaction mechanisms. We anticipate that our method will improve detection of epistatic interactions and will help to unravel the mysteries of complex biological systems. [PUBLICATION ABSTRACT]
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  • Health and Wellness at HiE
    Health and Wellness at HiE

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    Solgen, Solbar's natural soy isoflavone extracts will focus on "inside out beauty" and new clinical developments for reducing the symptoms of type 2 diabetes.
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