Top PDF Evidence that adaptation in Drosophila is not limited by mutation at single sites.

Evidence that adaptation in Drosophila is not limited by mutation at single sites.

Evidence that adaptation in Drosophila is not limited by mutation at single sites.

Adaptation in eukaryotes is generally assumed to be mutation-limited because of small effective population sizes. This view is difficult to reconcile, however, with the observation that adaptation to anthropogenic changes, such as the introduction of pesticides, can occur very rapidly. Here we investigate adaptation at a key insecticide resistance locus (Ace) in Drosophila melanogaster and show that multiple simple and complex resistance alleles evolved quickly and repeatedly within individual populations. Our results imply that the current effective population size of modern D. melanogaster populations is likely to be substantially larger ($100-fold) than commonly believed. This discrepancy arises because estimates of the effective population size are generally derived from levels of standing variation and thus reveal long-term population dynamics dominated by sharp—even if infrequent—bottlenecks. The short-term effective population sizes relevant for strong adaptation, on the other hand, might be much closer to census population sizes. Adaptation in Drosophila may therefore not be limited by waiting for mutations at single sites, and complex adaptive alleles can be generated quickly without fixation of intermediate states. Adaptive events should also commonly involve the simultaneous rise in frequency of independently generated adaptive mutations. These so-called soft sweeps have very distinct effects on the linked neutral polymorphisms compared to the standard hard sweeps in mutation-limited scenarios. Methods for the mapping of adaptive mutations or association mapping of evolutionarily relevant mutations may thus need to be reconsidered.
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ESCRT-0 is not required for ectopic Notch activation and tumor suppression in Drosophila.

ESCRT-0 is not required for ectopic Notch activation and tumor suppression in Drosophila.

To test whether the Hrs D28 , Stam 2L2896 mutant chromosome devoid of the l(2)gl mutation still possessed tumor-promoting ability, we analyzed mosaic FE, mosaic eye discs, or eye discs consisting predominantly of cells mutant for the recombined allele. Interestingly, these do not display loss of tissue architecture (Fig. 1D, H, P), as is the case of single Hrs or Stam mutant alleles, suggesting that the l(2)gl lesion in the original double mutant allele was responsible for the loss of tumor suppression phenotypes. These data indicate that simultaneous loss of both ESCRT-0 components do not lead to loss of tissue architecture, a striking difference to ESCRT-I, -II, -III mutations, which are tumorigenic [11,17,18]. Consistent with this surprising difference, we found that eye discs consisting predominantly of cells mutant for Hrs, or Stam or both Hrs and Stam progress to form adult eyes. These are smaller than wild-type and have a rough appearance but contain some mutant photoreceptors (Fig. 1Q–T) The scarcity of mutant adult photoreceptors might be due to cell death, as we occasionally see apoptotic cells in clones of Hrs, or Stam or both Hrs and Stam double mutants (Fig. 1I–L). In sheer contrast to these, a number of ESCRT-I, -II, -III mutations, such as those mapping to Tsg101, vps28, Vps25, vps20, when made homozygous in eye discs, display a Mutant Eye No Eclosion (MENE) phenotype that have been associated loss of tumor suppression in Drosophila [30]. Overall, these data suggest that the activity of Hrs and Stam is not tumor suppressive in two different Drosophila epithelial tissues. negative), as revealed by an antibody against mono- and poly- ubiquitin chains (Ubi). High magnification of the boxed areas is shown in insets. (G–H) Mutant FE cells (GFP-negative) show accumulation of the Notch receptor. Notch receptor has been revealed using anti-NICD specific to the intracellular domain of Notch. Apical as well as intracellular accumulations of Notch ICD epitope is seen in Hrs and Stam FE mutant cells. High magnification of the boxed areas is shown in insets. (I–K) Co-localization with anti Notch ECD (NECD) or Notch ICD (NICD) and Avl, marking early endosomes, in mosaic eye imaginal discs. Notch ECD is mainly accumulated in early endosomes in GFP-negative mutant tissue. (L–L’) Mosaic eye imaginal discs were stained with Ubi and anti-Domeless (Dome). Hrs, Stam mutant cells (GFP-negative) accumulate ubiquitylated cargoes and moderate levels of Dome, compared to WT. (M–O) Endocytic trafficking assay with anti-Notch ECD to label Notch at the surface of living imaginal discs. In WT tissue, after labeling (0 hrs), Notch is present mostly at the apical surface of the cell. After a 5-hour chase (5 hrs) Notch is completely degraded in WT but still present in endosomes in Stam mutant discs, indicating that Notch is internalized but it is not degraded.
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Evidence that mutation is universally biased towards AT in bacteria.

Evidence that mutation is universally biased towards AT in bacteria.

If natural selection plays a strong role in determining GC content it suggests that in many bacteria there are no truly neutrally evolving sites. The nature of such selection remains obscure. Because GC content correlates strongly across coding and noncoding sites genome-wide, natural selection acting on GC content probably relates to genome-wide functions such as replication or DNA maintenance and is less likely to be related to gene expression. Previous studies attempted to associate GC content with environmental factors such as growth temperature [44,45], exposure to UV [8], oxygen requirements [46], and the ability to fix nitrogen [47]. While these studies were thought by some to be inconclusive [3,44,48–51] they provide the best current explanations for the possible involvement of selection in determining nucleotide content. However, considering that bacteria belonging to such broad clades as Actinobacteria have similar genomic nucleotide contents even though they are exposed to different environments it becomes tempting to speculate that environmental variables may not be the only underlying determinants for the natural selection acting on nucleotide content. It is possible that selection on nucleotide content is also driven by more intra-organismal factors that can affect entire clades irrespective of environment. Examples of such factors can be the ability of the replication machinery to work better on GC or AT rich sequences, DNA packaging, defense against phages or creating barriers for horizontal gene transfer. More studies need to be carried out to probe the possible involvement of selection in determining bacterial nucleotide content.
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Synchronizing chromosome segregation by flux-dependent force equalization at kinetochores

Synchronizing chromosome segregation by flux-dependent force equalization at kinetochores

ments that nevertheless satisfy the SAC. Recent works support the finding that interkinetochore tension is dispensable in satisfying the SAC (O’Connell et al., 2008; Maresca and Salmon, 2009; Uchida et al., 2009). However, tension may provide an important readout to allow the detection and correction of potential errors be- fore anaphase onset (Pinsky and Biggins, 2005). Indeed, applica- tion of tension to kinetochores is known to promote its saturation with MTs (King and Nicklas, 2000), possibly by increasing MT stability due to spatial separation of kinetochore substrates from Aurora B at centromeres (Liu et al., 2009). However, maximizing tension by firmly grabbing MTs at their kinetochore attachment sites would not only prevent the release of erroneous attachments, but also hinder kMT flux/slippage, which could lead to chromo- some segregation defects (Ganem and Compton, 2006; Bakhoum et al., 2009). Therefore, at the expense of some local loss of ten- sion, MT affinity at kinetochores must be regulated to allow MTs to slip and possibly detach. According to our MT-coupling model, the system will respond globally to equilibrate tensions, and, con- sequently, all tension-dependent processes, precluding the need for tight spatial regulation of force distribution.
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All that glitters is not gold: diversification strategies in reserve portfolio management

All that glitters is not gold: diversification strategies in reserve portfolio management

Commodities were traditionally not regarded as part of the investment universe. When considering the volatility of returns, it’s similar to equities and it can be argued that therefore it’s an equally undesirable asset for a reserve management portfolio. However, there is a very important difference to be considered. In the recent past, several crises in the financial markets emphasized the degree of correlation among stocks and bonds. Cumming, Haβ and Schweizer (2011) considered that the losses experienced in stocks and bonds during the Asian crisis in 1997, Russia crisis in 1998, “dotcom” bubble in 2000 and terrorist attack to WTC in 2001, were an important driver for the search for diversification. As the return drivers for commodities are different, added value is undeniable during volatile market phases.
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The gene transformer of anastrepha fruit flies (Diptera, tephritidae) and its evolution in insects.

The gene transformer of anastrepha fruit flies (Diptera, tephritidae) and its evolution in insects.

The Tra protein in the tephritids Ceratitis, Bactrocera and Anastrepha appears to show a dual splicing role. On one hand it behaves as a splicing activator of dsx pre-mRNA2the binding of Tra to the female-specific exon promotes the inclusion of this exon into the mature mRNA. On the other hand, Tra acts as a splicing inhibitor of its own pre-mRNA2the binding of Tra to the male-specific exons prevents the inclusion of these exons into the mature mRNA. These observations raise the question of how Tra can perform this dual function. In this respect, the results obtained by other authors [30] with respect to Drosophila Tra2 and RBP1 function are pertinent here. The Drosophila Tra2 protein shows a dual splicing role. It behaves as a splicing activator of dsx pre- mRNA in the soma of Drosophila females, but also acts as a splicing inhibitor of the M1 intron in tra-2 pre-mRNA in the germ line of Drosophila males. This inhibition is exerted through the binding of Tra2 to specific ISS sites. However, the in vitro interaction between Tra2 and its ISS targets is not sufficient to cause M1 splicing inhibition; the presence of nuclear extracts is also required, Table 3. Average number of amino acid and nucleotide differences per site among tra genes in different species, plus standard errors, calculated using the bootstrap method (1000 replicates).
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Benthic macroinvertebrates as bioindicators of water quality in Billings Reservoir fishing sites (SP, Brazil)

Benthic macroinvertebrates as bioindicators of water quality in Billings Reservoir fishing sites (SP, Brazil)

maximum depth of 19 m. This reservoir shows a history of conflict among its multiple uses in recreation, the professional activity of artisanal fishing, power generation, effluent dilution, flood control and water supply (Cardoso-Silva  et  al., 2014). Though the water is degraded, affecting the composition and quality of the fish, there are many artisanal fishermen who survive through fishing. According to Alves da Silva et al. (2009) and Castro et al. (2009), between 2005 and 2007 at Billings Reservoir, approximately 100 families lived exclusively on resources from artisanal fisheries, but this number has been decreasing in recent years, which has been attributed principally to the pollution in the reservoir. These authors showed that the most representative species were acará (42.9%) (Geophagus brasiliensis, Quoy & Gaimard, 1824), tilapia (25.2%) (especially Oreochromis niloticus, Linnaeus, 1758, but also Tilapia rendalli, Boulenger, 1897) and lambari (16.3%) (Astyanax spp., especially Astyanax eigenmanniorum, Cope, 1894 and Astyanax scabripinnis, Jenyns, 1842). Although the environment surrounding the reservoir contains areas with good environmental preservation, many regions show urban development and agriculture,
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It Is Not That Simple nor Compelling!; Comment on “Translating Evidence Into Healthcare Policy and Practice: Single Versus Multi-faceted Implementation Strategies – Is There a Simple Answer to a Complex Question?”

It Is Not That Simple nor Compelling!; Comment on “Translating Evidence Into Healthcare Policy and Practice: Single Versus Multi-faceted Implementation Strategies – Is There a Simple Answer to a Complex Question?”

an either-or distinction when considering single versus multi- faceted interventions move the field of knowledge translation forward?” We concur with them in that the distinction is too simplistic and fails to appreciate the complexity associated with changing health professionals’ behaviour. To support their proposition, Harvey and Kitson 5 discussed the Promoting

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Modulatory effects of Tabebuia impetiginosa (Lamiales, Bignoniaceae) on doxorubicin-induced somatic mutation and recombination in Drosophila melanogaster

Modulatory effects of Tabebuia impetiginosa (Lamiales, Bignoniaceae) on doxorubicin-induced somatic mutation and recombination in Drosophila melanogaster

The wing Somatic Mutation and Recombination Test (SMART) in D. melanogaster was used to study genotoxicity of the medicinal plant Tabebuia impetiginosa. Lapachol (naphthoquinone) and b-lapachone (quinone) are the two main chemical constituents of T. impetiginosa. These compounds have several biological properties. They induce apoptosis by generating oxygen-reactive species, thereby inhibiting topoisomerases (I and II) or inducing other en- zymes dependent on NAD(P)H:quinone oxidoreductase 1, thus affecting cell cycle checkpoints. The SMART was used in the standard (ST) version, which has normal levels of cytochrome P450 (CYP) enzymes, to check the direct action of this compound, and in the high bioactivation (HB) version, which has a high constitutive level of CYP en- zymes, to check for indirect action in three different T. impetiginosa concentrations (10%, 20% or 40% w/w). It was observed that T. impetiginosa alone did not modify the spontaneous frequencies of mutant spots in either cross. The negative results observed prompted us to study this phytotherapeuticum in association with the reference mutagen doxorubicin (DXR). In co-treated series, T. impetiginosa was toxic in both crosses at higher concentration, whereas in the HB cross, it induced a considerable potentiating effect (from ~24.0 to ~95.0%) on DXR genotoxity. Therefore, further research is needed to determine the possible risks associated with the exposure of living organisms to this complex mixture.
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Multilevel Techniques for the Clustering Problem

Multilevel Techniques for the Clustering Problem

Comparing the two multilevel algorithms using MC as the chosen coarsening scheme, MLVL- GA produces better quality in 3 out of 8 cases and the difference in quality ranges from 2% to 24%. For the remaining 3 cases where MLVL-K-Means does better, the improvement is only marginally better (between 0.9% and 2%). Looking at the time spent MLVL-K-Means, in all the cases requires the least amount of time (up to 99% faster).With regard to the multilevel paradigm, it is somewhat unsatisfactory that its ability to enhance the convergence behavior of the two algorithms is not conclusive. However, This does not seem to be in line with with the general success established in other combinatorial optimization problems such as the graph partitioning problem [16] and the satisfiability problem [17]. The reason behind this sort of convergence behaviour observed in the multilevel paradigm is not obvious but we can speculate. As pointed earlier, the multilevel paradigm requires that any solution in any of the coarsened problems should induce a legitimate solution on the original problem. Thus at any stage after initialisation the current solution could simply be extended through all the problem levels to achieve a solution of the original problem. This requirement is violated in our case. The attributes of each object formed during each child level are calculated by taking the average of the attributes of two different objects from the parent level. The consequence of this procedure is that the optimization is carried out on different levels each having its own space. The clustering obtained at the coarse space and the original space do not have have the same cost with respect to the objective function.
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Development of a beamline high speed atomic force microscope and tuning of a mechanical oscillator via a force feedback strategy

Development of a beamline high speed atomic force microscope and tuning of a mechanical oscillator via a force feedback strategy

Apesar do gigante impacto que os Raios-X tiveram na ciência e tecnolo- gia ao longo do último século, estas carecem ainda de um carácter de análise local que só será possível obter tornando os feixes cada vez mais pequenos. Um esforço para os reduzir tem sido levado a cabo nas últimas décadas, mas a resolução espacial de uma experiência com este tipo de radiação ainda não ultrapassa as centenas de nanómetros. Este valor não se compara à resolução recorrentemente obtida com outras técnicas baseadas nos microscópios por varrimento de sonda ou pelo microscópio electrónico de varrimento, que con- seguem obter de forma rotineira uma resolução melhor que a do nanómetro. As técnicas de Raios-X também não oferecem geralmente a capacidade de manipulação mecânica da amostra. Surge assim a necessidade de levar a cabo uma combinação com um outro instrumento capaz de obter este tipo de informação. Um instrumento perfeito para obter caracterização de super- fícies e de manipulá-las à nano escala é o AFM. Esta combinação, o X-AFM, tem sido já tentada ao longo dos últimos anos, tendo obtido resultados in- teressantes. No entanto, os X-AFMs apresentados não abordam a dinâmica das amostras em estudo, um campo aberto pela primeira vez pelo AFM de alta velocidade. Este é o único instrumento que permite inspeccionar direc- tamente à nano escala fenómenos biológicos com escalas de tempo inferiores ao segundo, de forma não-invasiva,. Torna-se portanto interessante incor- porar a tecnologia de alta velocidade no X-AFM, perfazendo assim o tema central desta tese, o High Speed X-AFM (HSX-AFM). Identificam-se três áreas-chave em que o novo instrumento poderá ser útil a curto-prazo. O es- tudo dos efeitos da radiação em amostras de matéria mole em tempo real (da ordem do segundo), o uso do novo instrumento como localizador de um feixe de Raios-X e a sua utilização para fins de nano manipulação sob iluminação deste tipo de radiação.
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Dissection of a Complex Disease Susceptibility Region Using a Bayesian Stochastic Search Approach to Fine Mapping.

Dissection of a Complex Disease Susceptibility Region Using a Bayesian Stochastic Search Approach to Fine Mapping.

Monte Carlo methods can avoid limitations on the number of causal variants by sampling the model space rather than visiting all possible models. Here we adapt a Bayesian evolutionary stochastic search algorithm, GUESS [12, 13], to the fine mapping problem. This method, and its fast computational implementation, is tailored to efficiently explore the multimodal space created by multiple SNP models. However, the very dense SNP map that is required for fine mapping leads to extreme LD, which presents two specific challenges for GUESS. The first is that SNPs in extremely tight LD can cause numerical instability in model fitting, so we use minimal tagging to explore the model space and then expand all the tag models initially select- ed by GUESS (Fig 1). Second, posterior support is diluted across SNPs in tight LD, potentially preventing direct inference on the importance of individual SNPs. We therefore use posterior model probabilities and patterns of LD to define sets of SNPs which have strong joint posterior support for the hypothesis that one member of the set is causal for the trait. These are analo- gous to the credible sets generated in the Bayesian fine mapping framework which assumes a single causal variant per region [4], but allow for multiple causal variants.
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Consumption-Wealth Ratio and Expected Stock Returns: Evidence from Panel Data on G7 Countries

Consumption-Wealth Ratio and Expected Stock Returns: Evidence from Panel Data on G7 Countries

The link between macroeconomic and financial markets has long driven a great deal of theoretical and empirical work in the macroeconometric literature. Taking the asset- pricing equation as a starting point, and using a present-value approach, one can derive several interesting implications between macroeconomic data and future returns or excess returns. The work of Campbell (1987), Campbell and Shiller (1988b, 1987), Campbell and Deaton (1989), and Campbell and Mankiw (1989a), are good early examples of the connection between macroeconomic and financial variables. Indeed, one should expect some asset-return predictability following this literature, although the evidence is weak. Compare, for example, the results in (Fama and French, 1988; Pesaran and Timmermann, 1995) with those in Campbell and Thompson (2008). Recently, Guill´en et al. (2015) examine the usefulness of imposing different layers of present-value-model restrictions in forecasting financial data – a directly related issue.
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Gla-Rich Protein Is a Novel Vitamin K-Dependent Protein Present in Serum That Accumulates at Sites of Pathological Calcifications

Gla-Rich Protein Is a Novel Vitamin K-Dependent Protein Present in Serum That Accumulates at Sites of Pathological Calcifications

Mineralization of soft tissues is an abnormal process that occurs in any body tissue and can greatly in- crease morbidity and mortality. Vitamin K-depen- dent (VKD) proteins play a crucial role in these processes; matrix Gla protein is considered one of the most relevant physiological inhibitors of soft tissue calcification know to date. Several studies have suggested that other , still unknown , VKD pro- teins might also be involved in soft tissue calcifica- tion pathologies. We have recently identified in sturgeon a new VKD protein , Gla-rich protein (GRP) , which contains the highest ratio between number of Gla residues and size of the mature pro- tein so far identified. Although mainly expressed in cartilaginous tissues of sturgeon , in rat GRP is present in both cartilage and bone. We now show that GRP is a circulating protein that is also ex- pressed and accumulated in soft tissues of rats and humans , including the skin and vascular system in which, when affected by pathological calcifica- tions , GRP accumulates at high levels at sites of mineral deposition , indicating an association with calcification processes. The high number of Gla res- idues and consequent mineral binding affinity properties strongly suggest that GRP may directly influence min- eral formation , thereby playing a role in processes in- volving connective tissue mineralization. (Am J Pathol 2009, 175:2288 –2298; DOI: 10.2353/ajpath.2009.090474)
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Wolbachia-induced cytoplasmic incompatibility is associated with decreased Hira expression in male Drosophila.

Wolbachia-induced cytoplasmic incompatibility is associated with decreased Hira expression in male Drosophila.

Previous studies both in vitro and in vivo have shown that Wolbachia infection may affect the expression of various host genes, including those associated with immunity, fertilization, and development [21–23]. For example, wMelPop strain of Wolbachia has been shown to be capable of inducing immune upregulation in Anopheles gambiae and Aedes aegypti mosquitoes [23,24]. Even in a cell line naturally infected with Wolbachia, the expression of antioxidant proteins is also upregulated [22]. However, the association of CI strength induced by Wolbachia with the gene expression level in hosts is unknown. Here, we used two lines from both D. melanogaster and D. simulans infected with different Wolbachia strains to determine if Hira gene expression is correlated with CI. Our results demonstrate that for both Dmel wMel and Dsim wRi 1- day-old males, which express strong CI, the Hira expression levels are significantly decreased compared to Wolbachia-uninfected and wAu-infected males which induce either weak or no CI. Furthermore, increasing male age was correlated with increasing hatch rates (Tables 1, 2). Correspondingly, Hira expression was significantly lower in younger males (Figures 3, 4), suggesting that down regulation of Hira expression in male Drosophila might be causally linked to the CI strength.
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In vivo evidence that TRAF4 is required for central nervous system myelin homeostasis.

In vivo evidence that TRAF4 is required for central nervous system myelin homeostasis.

Tumor Necrosis Factor Receptor-Associated Factors (TRAFs) are major signal transducers for the TNF and interleukin-1/Toll- like receptor superfamilies. However, TRAF4 does not fit the paradigm of TRAF function in immune and inflammatory responses. Its physiological and molecular functions remain poorly understood. Behavorial analyses show that TRAF4- deficient mice (TRAF4-KO) exhibit altered locomotion coordination typical of ataxia. TRAF4-KO central nervous system (CNS) ultrastructure shows strong myelin perturbation including disorganized layers and disturbances in paranode organization. TRAF4 was previously reported to be expressed by CNS neurons. Using primary cell culture, we now show that TRAF4 is also expressed by oligodendrocytes, at all stages of their differentiation. Moreover, histology and electron microscopy show degeneration of a high number of Purkinje cells in TRAF4-KO mice, that was confirmed by increased expression of the Bax pro-apoptotic marker (immunofluorescence), TUNEL analysis, and caspase-3 activation and PARP1 cleavage (western blotting). Consistent with this phenotype, MAG and NogoA, two myelin-induced neurite outgrowth inhibitors, and their neuron partners, NgR and p75NTR were overexpressed (Q-RT-PCR and western blotting). The strong increased phosphorylation of Rock2, a RhoA downstream target, indicated that the NgR/p75NTR/RhoA signaling pathway, known to induce actin cytoskeleton rearrangement that favors axon regeneration inhibition and neuron apoptosis, is activated in the absence of TRAF4 (western blotting). Altogether, these results provide conclusive evidence for the pivotal contribution of TRAF4 to myelination and to cerebellar homeostasis, and link the loss of TRAF4 function to demyelinating or neurodegenerative diseases.
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Histone H1 of Trypanosoma cruzi is concentrated in the nucleolus region and disperses upon phosphorylation during progression to mitosis

Histone H1 of Trypanosoma cruzi is concentrated in the nucleolus region and disperses upon phosphorylation during progression to mitosis

The nucleosome, the basic chromatin unit, is assembled by wrapping DNA around an octamer formed by two copies of histone H2A, H2B, H3, and H4 proteins. A fifth histone, called histone H1, packs the chromatin by contacting internucleoso- mal DNA and the nucleosome particle (50). Histone H1 is formed by a globular domain flanked by a long unstructured C-terminal portion, comprising almost half of the protein, and by a short and also nonstructured N-terminal domain. The C-terminal domain is enriched in basic amino acids that inter- act with the negative phosphodiester charges of DNA through S/TPKK motifs (26). The globular portion contacts the core histones and the nucleosomal DNA (3), favoring chromatin compaction, which prevents the access of chromatin remodel- ing factors and therefore restricts transcription and replication (10). Fluorescence recovery after photobleaching experiments have shown that the chromatin residence time of histone H1 is much shorter than that of other histones, suggesting that his- tone H1 dynamically associates with the nucleosome particles, contributing to several nuclear processes involving chromatin condensation and decondensation (10, 31, 36). However, when histone H1 is absent, chromatin decondenses (20, 47).
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The duty to take care and liability for the act of the things in comparative law

The duty to take care and liability for the act of the things in comparative law

Whereas the presumption of responsibility established by that article as to one who has under his guard an inanimate object that has caused harm to another can be rebutted only by proving a cas fortuit, a force majeure, or a cause étrangère that cannot be imputed to him; as it does not suffice to prove that he did not commit any fault or that the cause of the harmful act has not been ascertained; whereas, on April 22 1925, a truck belonging to the Compagnie Les Galeries Belfortaises knocked down and injured the minor Lise Jand’heur; as the challenged decision refused to apply the article cited above on the ground that an accident caused by an automobile in movement, under the impulsion and direction of an individual, does not, so long as it has not been shown that the accident was due to a defect in the automobile, constitute the act of an object that one has under his guard within the meaning of paragraph 1 of article 1384, and that, in consequence, the victim must, in order to obtain compensation for the injury, establish a fault imputable to the driver. But whereas the law does not distinguish, for purposes of application of the presumption that it has established, whether the object that caused the harm was or was not put in motion by man; as it is not necessary that there be a defect in the object capable of causing the damage as article 1384 attaches the responsibility to the guard of the object, not to the object itself. From which it follows that, in ruling as it did, the challenged decision reversed the legal burden of proof and violated the article of law cited above. For these reasons, quash…
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Courtship initiation is stimulated by acoustic signals in Drosophila melanogaster.

Courtship initiation is stimulated by acoustic signals in Drosophila melanogaster.

In order to examine whether males use the arista-Johnston’s organ auditory system to detect the moving-female signal, we measured courtship behavior of an auditory mutant, 5D10 [21], and found a defect in courtship initiation in the dark, with a mean latency of 5536185 sec, which was significantly lower than that of its genetic control line, 40A-G13 (control 149617 sec, P,0.005), supporting a role of the auditory system in courtship initiation. We also surgically manipulated arista function and compared courtship responses to those of intact males. Aristae of wild-type males were either fixed to the third antennal segment with a small amount of wax or partially amputated with fine scissors. The males with waxed-arista showed a significantly longer latency of courtship initiation (8296240 sec) than intact males courting intact females (4356193 sec, P,0.05). The level corresponded to that of intact males courting decapitated silent females. This was consistent with a freely moving arista being essential for the female-movement detection. However, in this manipulation, the wax also covered some surface area of the third antennal segment so that it is possible that olfactory function was also disrupted, which may cause delayed courtship initiation. Therefore, we next cut most (more than three quarters) of both aristae off with fine scissors. The males with the partial aristae (1/4 arista) showed a normal level of courtship latency compared to intact males (3316100 sec, P.0.5). This implies that the full length arista is not essential for motion-signal detection. It is not clear whether the remaining quarter of arista is sufficient for the function or arista itself is not required for this signal detection. It is also possible that Johnston’s organ receives mechanosensory signals from other bristles on the second segment and not just the arista. Since Gr68a- GAL4 is broadly expressed in mechanosensory neurons, it also remains possible that attention-getting auditory stimuli maybe sensed by cells other than those in Johnston’s organ.
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The Enigmatic Eosinophil: Investigation of the Biological Role of Eosinophils in Parasitic Helmint Infection

The Enigmatic Eosinophil: Investigation of the Biological Role of Eosinophils in Parasitic Helmint Infection

(iii) The larval cestode Mesocestoides corti - M. corti is the quintessential laboratory parasite that has routinely been used by immunologists studying IL- 5, eosinophils and other immune responses to hel- minths (e.g. Pollacco et al. 1978, Cook et al. 1988, Dent et al. 1990). Carnivores, which are the defini- tive host for M. corti, become infected by eating intermediate hosts – a wide range of vertebrates, including reptiles, birds, rats and mice – infected with larval stages known as tetrathyridia. In the car- nivore gut, the tetrathyridia develop into adult worms which reproduce both sexually and asexually and release eggs which pass out in the faeces. The next stage of the life cycle is uncertain: the eggs are thought to be ingested by soil arthropods which are later ingested by vertebrate intermediate hosts. The resulting tetrathyridia inhabit the peritoneal cavity and liver where they reproduce asexually. This para- site is particularly amenable to experimentation as it can be repeatedly passaged by simply isolating tetrathyridia from the peritoneal cavity of an infected mouse and injecting them directly into the perito- neal cavities of uninfected mice. Since this culture method bypasses several stages in the life cycle, it should be noted that laboratory strains of M. corti which have been cultured for innumerable genera- tions, without selection through the other hosts in the life cycle, may be biologically substantially dif- ferent from the parasite originally isolated in 1965 (Specht & Voge 1965).
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