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Search Results: 1 - 10 of 26254 matches for " Martin ?andera "
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Variation in Apical Hook Length Reflects the Intensity of Sperm Competition in Murine Rodents
Martinandera, Tomá? Albrecht, Pavel Stopka
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0068427
Abstract: Background Post-copulatory sexual selection has been shown to shape morphology of male gametes. Both directional and stabilizing selection on sperm phenotype have been documented in vertebrates in response to sexual promiscuity. Methodology Here we investigated the degree of variance in apical hook length and tail length in six taxa of murine rodents. Conclusions Tail sperm length and apical hook length were positively associated with relative testis mass, our proxy for levels of sperm competition, thus indicating directional post-copulatory selection on sperm phenotypes. Moreover, our study shows that increased levels of sperm competition lead to the reduction of variance in the hook length, indicating stabilizing selection. Hence, the higher risk of sperm competition affects increasing hook length together with decreasing variance in the hook length. Species-specific post-copulatory sexual selection likely optimizes sperm morphology.
Novel OBP genes similar to hamster Aphrodisin in the bank vole, Myodes glareolus
Romana Stopková, Zbyněk Zdráhal, ?těpán Ryba, Ond?ej ?edo, Martinandera, Pavel Stopka
BMC Genomics , 2010, DOI: 10.1186/1471-2164-11-45
Abstract: Here we show that Aphrodisin-like proteins exist in other species, belong to a group of Odorant Binding Proteins (Obp), and contrary to the expression of Aphrodisin only in hamster genital tract and parotid glands of females, we have detected these transcripts in both sexes of M. glareolus with the expression confirmed in various tissues including prostate, prepucial and salivary glands, liver and uterus. On the level of mRNA, we have detected three different gene variants. To assess their relevance for chemical communication we investigated the occurrence of particular proteins in saliva, urine and vaginal discharge. On the protein level we confirmed the presence of Obp2 and Obp3 in both saliva and urine. Appropriate bands in the range of 17-20 kDa from vaginal discharge were, however, beyond the MS detection limits.Our results demonstrate that three novel Obps (Obp1, Obp2, and Obp3) are predominant lipocalins in Myodes urine and saliva. On the protein level we have detected further variants and thus we assume that similarly as Major Urinary Proteins in mice, these proteins may be important in chemical communication in this Cricetid rodent.Lipocalins are known to be involved in many important biological processes, of which one of them is chemical communication. Due to a conservative tertiary structure forming typical beta barrel all lipocalins share ability to bind various ligands of different size and structure. For some of the lipocalin members there already exists evidence for causing significant behavioural effects by their specific pheromonal ligands. The main lipocalin proteins studied to date in association with chemical communication are the mouse Major Urinary Proteins (Mup) secreted predominantly in the urine and saliva and Odorant Binding Proteins (Obp) with predominant site of expression in nasal tissue.In mice, urine is an important source of chemical information, frequently investigated by conspecifics and having the ability to elicit various behaviou
The present status of Dormice in the Czech Republic
Miloš Andera
Hystrix : the Italian Journal of Mammalogy , 1995, DOI: 10.4404/hystrix-6.1-2-4025
Abstract: The present status of dormouse distribution patterns in the Czech Republic is reported. In all, four species are presently found within our territory and distribution ranges are plotted on a 10x10 km grid. M. avellanarius is the most common and wide-spread species, while M. glis exhibits considerable regional variability in its distribution pattern. D. nitedula has only a limited distribution within our country. E. quercinus is the rarest of our species, its present mosaic of distribution seems to be a relict character. Riassunto Lo stato attuale dei Mioxidi nella Repubblica Ceca - Viene riportato il presente stato dei pattern di distribuzione dei Mioxidi nella Repubblica ceca. In tutto sul nostro territorio sono presenti quattro specie, le cui distribuzioni sono riportate su reticolo cartografico UTM 10x10 km. M. avellanarius è la specie più comune e diffusa, mentre M. glis presenta una considerevole variabilità regionale nel suo pattern di distribuzione. Per quanto riguarda D. nitedula, questa specie ha una distribuzione limitata nel nostro territorio. E. quercinus è la specie più rara e la sua distribuzione attuale a mosaico ha evidentemente un carattere relitto.
A synopsis of the mammals of the Czech Republic
Jan Zima,Miloš Andera
Hystrix : the Italian Journal of Mammalogy , 1996, DOI: 10.4404/hystrix-8.1-2-4099
Abstract: There are 85 mammalian species reported recently from the territory of the Czech Republic. Ten species disappeared from the territory in various historical periods, and seven of them have been reintroduced or reappeared again. No species can be considered endemic, but populations of several species are isolated inside the region concerned. At least fourteen allochthonous species were introduced. Currently, 30 species are protected by law and considered endangered.
Selective BRAFV600E Inhibitor PLX4720, Requires TRAIL Assistance to Overcome Oncogenic PIK3CA Resistance
Eftychia Oikonomou, Michal Koc, Vladimira Sourkova, Ladislav Andera, Alexander Pintzas
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0021632
Abstract: Documented sensitivity of melanoma cells to PLX4720, a selective BRAFV600E inhibitor, is based on the presence of mutant BRAFV600E alone, while wt-BRAF or mutated KRAS result in cell proliferation. In colon cancer appearance of oncogenic alterations is complex , since BRAF, like KRAS mutations, tend to co-exist with those in PIK3CA and mutated PI3K has been shown to interfere with the successful application of MEK inhibitors. When PLX4720 was used to treat colon tumours, results were not encouraging and herein we attempt to understand the cause of this recorded resistance and discover rational therapeutic combinations to resensitize oncogene driven tumours to apoptosis. Treatment of two genetically different BRAFV600E mutant colon cancer cell lines with PLX4720 conferred complete resistance to cell death. Even though p-MAPK/ ERK kinase (MEK) suppression was achieved, TRAIL, an apoptosis inducing agent, was used synergistically in order to achieve cell death by apoptosis in RKOBRAFV600E/PIK3CAH1047 cells. In contrast, for the same level of apoptosis in HT29BRAFV600E/PIK3CAP449T cells, TRAIL was combined with 17-AAG, an Hsp90 inhibitor. For cells where PLX4720 was completely ineffective, 17-AAG was alternatively used to target mutant BRAFV600E. TRAIL dependence on the constitutive activation of BRAFV600E is emphasised through the overexpression of BRAFV600E in the permissive genetic background of colon adenocarcinoma Caco-2 cells. Pharmacological suppression of the PI3K pathway further enhances the synergistic effect between TRAIL and PLX4720 in RKO cells, indicating the presence of PIK3CAMT as the inhibitory factor. Another rational combination includes 17-AAG synergism with TRAIL in a BRAFV600E mutant dependent manner to commit cells to apoptosis, through DR5 and the amplification of the apoptotic pathway. We have successfully utilised combinations of two chemically unrelated BRAFV600E inhibitors in combination with TRAIL in a BRAFV600E mutated background and provided insight for new anti-cancer strategies where the activated PI3KCA mutation oncogene should be suppressed.
BRAF and RAS oncogenes regulate Rho GTPase pathways to mediate migration and invasion properties in human colon cancer cells: a comparative study
Eleni Makrodouli, Eftychia Oikonomou, Michal Koc, Ladislav Andera, Takehiko Sasazuki, Senji Shirasawa, Alexander Pintzas
Molecular Cancer , 2011, DOI: 10.1186/1476-4598-10-118
Abstract: Colon adenocarcinoma cells with endogenous as well as ectopically expressed or silenced oncogenic mutations of BRAFV600E, KRASG12V and HRASG12V were employed. Signalling pathways and Rho GTPases were inhibited with specific kinase inhibitors and siRNAs. Cell motility and invasion properties were correlated with cytoskeletal properties and Rho GTPase activities.Evidence presented here indicate that BRAFV600E significantly induces cell migration and invasion properties in vitro in colon cancer cells, at least in part through activation of RhoA GTPase. The relationship established between BRAFV600E and RhoA activation is mediated by the MEK-ERK pathway. In parallel, KRASG12V enhances the ability of colon adenocarcinoma cells Caco-2 to migrate and invade through filopodia formation and PI3K-dependent Cdc42 activation. Ultimately increased cell migration and invasion, mediated by Rac1, along with the mesenchymal morphology obtained through the Epithelial-Mesenchymal Transition (EMT) were the main characteristics rendered by HRASG12V in Caco-2 cells. Moreover, BRAF and KRAS oncogenes are shown to cooperate with the TGFβ-1 pathway to provide cells with additional transforming properties.This study discriminates oncogene-specific cell migration and invasion pathways mediated by Rho GTPases in colon cancer cells and reveals potential new oncogene-specific characteristics for targeted therapeutics.Colorectal cancer represents a complex disease that involves multiple steps of genetic alterations, like inactivation of tumour suppressor genes and activation of oncogenes, often associated with progression from premalignant lesion (adenoma) to invasive adenocarcinoma [1]. KRAS mutations have been found in about 35% of colon carcinomas that mainly occur at codons 12, 13 and 61, resulting in a constitutively active form of KRAS GTPase. Consequently, multiple RAS effector pathways that regulate fundamental biological processes such as proliferation, apoptosis, and cell motility, beco
A Yield Mapping Procedure Based on Robust Fitting Paraboloid Cones on Moving Elliptical Neighborhoods and the Determination of Their Size Using a Robust Variogram  [PDF]
Martin Bachmaier
Positioning (POS) , 2010, DOI: 10.4236/pos.2010.11004
Abstract: The yield map is generated by fitting the yield surface shape of yield monitor data mainly using paraboloid cones on floating neighborhoods. Each yield map value is determined by the fit of such a cone on an elliptical neighborhood that is wider across the harvest tracks than it is along them. The coefficients of regression for modeling the paraboloid cones and the scale parameter are estimated using robust weighted M-estimators where the weights decrease quadratically from 1 in the middle to zero at the border of the selected neighborhood. The robust way of estimating the model parameters supersedes a procedure for detecting outliers. For a given neighborhood shape, this yield mapping method is implemented by the Fortran program paraboloidmapping.exe, which can be downloaded from the web. The size of the selected neighborhood is considered appropriate if the variance of the yield map values equals the variance of the true yields, which is the difference between the variance of the raw yield data and the error variance of the yield monitor. It is estimated using a robust variogram on data that have not had the trend removed.
Sources of inaccuracy when estimating economically optimum N fertilizer rates  [PDF]
Martin Bachmaier
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.33037
Abstract: Nitrogen rate trials are often performed to determine the economically optimum N application rate. For this purpose, the yield is modeled as a function of the N application. The regression analysis provides an estimate of the modeled function and thus also an estimate of the economic optimum, Nopt. Obtaining the accuracy of such estimates by confidence intervals for Nopt is subject to the model assumptions. The dependence of these assumptions is a further source of inaccuracy. The Nopt estimate also strongly depends on the N level design, i.e., the area on which the model is fitted. A small area around the supposed Nopt diminishes the dependence of the model assumptions, but prolongs the confidence interval. The investigations of the impact of the mentioned sources on the inaccuracy of the Nopt estimate rely on N rate trials on the experimental field Sieblerfeld (Bavaria). The models applied are the quadratic and the linear-plus-plateau yield regression model.
Waiting for Redemption in The House of Asterion: A Stylistic Analysis  [PDF]
Martin Tilney
Open Journal of Modern Linguistics (OJML) , 2012, DOI: 10.4236/ojml.2012.22007
Abstract: The House of Asterion is a short story by Jorge Luis Borges that retells the classical myth of the Cretan Minotaur from an alternate perspective. The House of Asterion features the Minotaur, aka Asterion, who waits for “redemption” in his labyrinth. Many literary critics have suggested that the Borgesian labyrinth is a metaphor for human existence and the universe itself. Others have correctly interpreted Asterion’s ironic death at the hands of Theseus as his eagerly awaited redemption. Borges’ subversion of the reader’s expectations becomes the departure point for a systemic functional stylistic analysis of the story in one of its English translations, revealing how deeper-level meanings in the text are construed through its lexicogrammatical structure. A systemic functional stylistic reading suggests that on a higher level of reality, Asterion’s redemption is not only the freedom that death affords, but also a transformation that transcends his fictional universe. Asterion’s twofold redemption is brought about not only by the archetypal hero Theseus but also by the reader, who through the process of reading enables Asterion’s emancipation from the labyrinth.
A Macroeconomic Model of Biodiversity Protection  [PDF]
David Martin
Theoretical Economics Letters (TEL) , 2013, DOI: 10.4236/tel.2013.35A1006
Abstract:

Many biodiversity researchers have responded to the financial constraints faced by policy makers to develop models based upon the “Noah’s Ark” metaphor, implying that society can save only a limited amount of biodiversity. Unfortunately, as Herman Daly (Land Economics, 1991) pointed out, such microeconomic rules can allow an ark to sink albeit in some optimal fashion. So, I step back to look at the macroeconomic question, how big should the ark be? I start with Norgaard’s (Ecological Economics, 2010) framework, which is based upon the concept of a production possibility frontier combined with a sustainability criterion. I develop a model from that starting point by shifting to an isoquant framework while maintaining the strong sustainability criterion. I demonstrate how this model allows for identifying and addressing the key biodiversity protection policy criteria at the macroeconomic level. One key conclusion from this modeling is that Daly’s analysis remains remarkably prescient.

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