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Sample records for pili sex

  1. Multibody simulation of adhesion pili

    CERN Document Server

    Zakrisson, Johan; Servin, Martin; Axner, Ove; Lacoursiere, Claude; Andersson, Magnus

    2014-01-01

    We present a coarse grained rigid multibody model of a subunit assembled helix-like polymer, e.g., adhesion pili expressed by bacteria, that is capable of describing the polymers force-extension response. With building blocks representing individual subunits the model appropriately describes the complex behavior of pili expressed by the gram-negative uropathogenic Escherichia coli bacteria under the action of an external force. Numerical simulations show that the dynamics of the model, which include both the effects of unwinding and rewinding, are in good quantitative agreement with the characteristic force-extension response as observed experimentally for type 1 and P pili. By tuning the model, it is also possible to reproduce the force-extension response in the presence of anti-shaft antibodies, which dramatically changes the mechanical properties. Thus, the model and the results in this work give enhanced understanding of how a pilus unwinds under action of external forces and provide new perspective of th...

  2. Damping effect of helix-like pili

    CERN Document Server

    Zakrisson, Johan; Axner, Ove; Andersson, Magnus

    2014-01-01

    Biopolymers are vital structures for many living organisms; for a variety of bacteria, adhesion polymers play a crucial role for the initiation of colonization. Some bacteria express, on their surface, attachment organelles (pili) that comprise subunits formed into stiff helix-like structures that possess unique biomechanical properties. These helix-like structures possess a high degree of flexibility that gives the biopolymers a unique extendibility. This has been considered beneficial for piliated bacteria adhering to host surfaces in the presence of a fluid flow. We show in this work that helix-like pili have the ability to act as efficient dampers of force that can, for a limited time, lower the load on the force-mediating adhesin-receptor bond on the tip of an individual pilus. The model presented is applied to bacteria adhering with a single pilus of either of the two most common types expressed by uropathogenic Escherichia coli, P or type 1 pili, subjected to realistic flows. The results indicate that ...

  3. Dynamic properties of bacterial pili measured by optical tweezers

    CERN Document Server

    Fallman, Erik; Schedin, Staffan; Jass, Jana; Uhlin, Bernt Eric; Axner, Ove

    2014-01-01

    The ability of uropathogenic Escherichia coli (UPEC) to cause urinary tract infections is dependent on their ability to colonize the uroepithelium. Infecting bacteria ascend the urethra to the bladder and then kidneys by attaching to the uroepithelial cells via the differential expression of adhesins. P pili are associated with pyelonephritis, the more severe infection of the kidneys. In order to find means to treat pyelonephritis, it is therefore of interest to investigate the properties P pili. The mechanical behavior of individual P pili of uropathogenic Escherichia coli has recently been investigated using optical tweezers. P pili, whose main part constitutes the PapA rod, composed of ~1000 PapA subunits in a helical arrangement, are distributed over the bacterial surface and mediate adhesion to host cells. We have earlier studied P pili regarding its stretching/elongation properties where we have found and characterized three different elongation regions, of which one constitute an unfolding of the quate...

  4. Intramolecular amide bonds stabilize pili on the surface of bacilli

    Energy Technology Data Exchange (ETDEWEB)

    Budzik, Jonathan M.; Poor, Catherine B.; Faull, Kym F.; Whitelegge, Julian P.; He, Chuan; Schneewind, Olaf; (UC); (UCLA-MED)

    2010-01-12

    Gram-positive bacteria elaborate pili and do so without the participation of folding chaperones or disulfide bond catalysts. Sortases, enzymes that cut pilin precursors, form covalent bonds that link pilin subunits and assemble pili on the bacterial surface. We determined the x-ray structure of BcpA, the major pilin subunit of Bacillus cereus. The BcpA precursor encompasses 2 Ig folds (CNA{sub 2} and CNA{sub 3}) and one jelly-roll domain (XNA) each of which synthesizes a single intramolecular amide bond. A fourth amide bond, derived from the Ig fold of CNA{sub 1}, is formed only after pilin subunits have been incorporated into pili. We report that the domains of pilin precursors have evolved to synthesize a discrete sequence of intramolecular amide bonds, thereby conferring structural stability and protease resistance to pili.

  5. Archaeal type IV pili and their involvement in biofilm formation.

    Science.gov (United States)

    Pohlschroder, Mechthild; Esquivel, Rianne N

    2015-01-01

    Type IV pili are ancient proteinaceous structures present on the cell surface of species in nearly all bacterial and archaeal phyla. These filaments, which are required for a diverse array of important cellular processes, are assembled employing a conserved set of core components. While type IV pilins, the structural subunits of pili, share little sequence homology, their signal peptides are structurally conserved allowing for in silico prediction. Recently, in vivo studies in model archaea representing the euryarchaeal and crenarchaeal kingdoms confirmed that several of these pilins are incorporated into type IV adhesion pili. In addition to facilitating surface adhesion, these in vivo studies also showed that several predicted pilins are required for additional functions that are critical to biofilm formation. Examples include the subunits of Sulfolobus acidocaldarius Ups pili, which are induced by exposure to UV light and promote cell aggregation and conjugation, and a subset of the Haloferax volcanii adhesion pilins, which play a critical role in microcolony formation while other pilins inhibit this process. The recent discovery of novel pilin functions such as the ability of haloarchaeal adhesion pilins to regulate swimming motility may point to novel regulatory pathways conserved across prokaryotic domains. In this review, we will discuss recent advances in our understanding of the functional roles played by archaeal type IV adhesion pili and their subunits, with particular emphasis on their involvement in biofilm formation.

  6. Molecular analysis of the UV-inducible pili operon from Sulfolobus acidocaldarius

    NARCIS (Netherlands)

    Wolferen, Marleen van; Ajon, Małgorzata; Driessen, Arnold J.M.; Albers, Sonja-Verena

    2013-01-01

    Upon ultraviolet (UV) stress, hyperthermophilic Sulfolobus species show a highly induced transcription of a gene cluster responsible for pili biogenesis: the UV-inducible pili operon (ups operon). This operon is involved in UV-induced pili assembly, cellular aggregation, and subsequent DNA exchange

  7. Expressing the Geobacter metallireducens PilA in Geobacter sulfurreducens Yields Pili with Exceptional Conductivity

    Science.gov (United States)

    Tan, Yang; Adhikari, Ramesh Y.; Malvankar, Nikhil S.; Ward, Joy E.; Woodard, Trevor L.; Nevin, Kelly P.

    2017-01-01

    ABSTRACT The electrically conductive pili (e-pili) of Geobacter sulfurreducens serve as a model for a novel strategy for long-range extracellular electron transfer. e-pili are also a new class of bioelectronic materials. However, the only other Geobacter pili previously studied, which were from G. uraniireducens, were poorly conductive. In order to obtain more information on the range of pili conductivities in Geobacter species, the pili of G. metallireducens were investigated. Heterologously expressing the PilA gene of G. metallireducens in G. sulfurreducens yielded a G. sulfurreducens strain, designated strain MP, that produced abundant pili. Strain MP exhibited phenotypes consistent with the presence of e-pili, such as high rates of Fe(III) oxide reduction and high current densities on graphite anodes. Individual pili prepared at physiologically relevant pH 7 had conductivities of 277 ± 18.9 S/cm (mean ± standard deviation), which is 5,000-fold higher than the conductivity of G. sulfurreducens pili at pH 7 and nearly 1 million-fold higher than the conductivity of G. uraniireducens pili at the same pH. A potential explanation for the higher conductivity of the G. metallireducens pili is their greater density of aromatic amino acids, which are known to be important components in electron transport along the length of the pilus. The G. metallireducens pili represent the most highly conductive pili found to date and suggest strategies for designing synthetic pili with even higher conductivities. PMID:28096491

  8. Dynamics of gonococcal type IV pili during infection.

    Science.gov (United States)

    Opitz, Dirk; Clausen, Martin; Maier, Berenike

    2009-07-13

    Type IV pili are important bacterial virulence factors that mediate attachment to mammalian host cells and elicit downstream signals. When adhered to abiotic surfaces, the human pathogen Neisseria gonorrhoeae generates force by retracting these polymeric cell appendages. We recently found that single pili generate stalling forces that exceed 100 pN, but it is unclear whether bacteria generate force once they adhere to their human host cells. Here, we report that pili retract very actively during infection of human epithelial cells. The retraction velocity is bimodal and the high velocity mode persisted at higher forces in contrast to an abiotic environment. Bacteria generate considerable force during infection, but the maximum force is reduced from 120+/-40 pN on abiotic surfaces to 70+/-20 pN on epithelial cells, most likely due to elastic effects. Velocity and maximum force of pilus retraction are largely independent of the infection period within 1 h and 24 h post-infection. Thus, the force generated by type IV pili during infection is high enough to induce cytoskeletal rearrangements in the host cell.

  9. Single-cell force spectroscopy of pili-mediated adhesion

    Science.gov (United States)

    Sullan, Ruby May A.; Beaussart, Audrey; Tripathi, Prachi; Derclaye, Sylvie; El-Kirat-Chatel, Sofiane; Li, James K.; Schneider, Yves-Jacques; Vanderleyden, Jos; Lebeer, Sarah; Dufrêne, Yves F.

    2013-12-01

    Although bacterial pili are known to mediate cell adhesion to a variety of substrates, the molecular interactions behind this process are poorly understood. We report the direct measurement of the forces guiding pili-mediated adhesion, focusing on the medically important probiotic bacterium Lactobacillus rhamnosus GG (LGG). Using non-invasive single-cell force spectroscopy (SCFS), we quantify the adhesion forces between individual bacteria and biotic (mucin, intestinal cells) or abiotic (hydrophobic monolayers) surfaces. On hydrophobic surfaces, bacterial pili strengthen adhesion through remarkable nanospring properties, which - presumably - enable the bacteria to resist high shear forces under physiological conditions. On mucin, nanosprings are more frequent and adhesion forces larger, reflecting the influence of specific pili-mucin bonds. Interestingly, these mechanical responses are no longer observed on human intestinal Caco-2 cells. Rather, force curves exhibit constant force plateaus with extended ruptures reflecting the extraction of membrane nanotethers. These single-cell analyses provide novel insights into the molecular mechanisms by which piliated bacteria colonize surfaces (nanosprings, nanotethers), and offer exciting avenues in nanomedicine for understanding and controlling the adhesion of microbial cells (probiotics, pathogens).

  10. The biomechanical properties of F1C pili

    CERN Document Server

    Castelain, Mickaël; Klinth, Jeanna; Lindberg, Stina; Andersson, Magnus; Uhlin, Bernt Eric; Axner, Ove

    2014-01-01

    Uropathogenic Escherichia coli (UPEC) express various kinds of organelles, so-called pili or fimbriae, that mediate adhesion to host tissue in the urinary tract through specific receptor-adhesin interactions. The biomechanical properties of these pili have been considered important for the ability of bacteria to withstand shear forces from rinsing urine flows. Force measuring optical tweezers have been used to characterize individual organelles of F1C type expressed by UPEC bacteria with respect to such properties. Qualitatively, the force-vs.-elongation response was found to be similar to that of other types of helix-like pili expressed by UPEC, i.e. type 1, P, and S, with force-induced elongation in three regions of which one represents the important uncoiling mechanism of the helix-like quaternary structure. Quantitatively, the steady-state uncoiling force was assessed to 26.4(1.4) pN, which is similar to those of other pili (which range from 21 pN for SI to 30 pN for type 1). The corner velocity for dynam...

  11. Pili-Induced Clustering of N. gonorrhoeae Bacteria.

    Directory of Open Access Journals (Sweden)

    Johannes Taktikos

    Full Text Available Type IV pili (Tfp are prokaryotic retractable appendages known to mediate surface attachment, motility, and subsequent clustering of cells. Tfp are the main means of motility for Neisseria gonorrhoeae, the causative agent of gonorrhea. Tfp are also involved in formation of the microcolonies, which play a crucial role in the progression of the disease. While motility of individual cells is relatively well understood, little is known about the dynamics of N. gonorrhoeae aggregation. We investigate how individual N. gonorrhoeae cells, initially uniformly dispersed on flat plastic or glass surfaces, agglomerate into spherical microcolonies within hours. We quantify the clustering process by measuring the area fraction covered by the cells, number of cell aggregates, and their average size as a function of time. We observe that the microcolonies are also able to move but their mobility rapidly vanishes as the size of the colony increases. After a certain critical size they become immobile. We propose a simple theoretical model which assumes a pili-pili interaction of cells as the main clustering mechanism. Numerical simulations of the model quantitatively reproduce the experimental data on clustering and thus suggest that the agglomeration process can be entirely explained by the Tfp-mediated interactions. In agreement with this hypothesis mutants lacking pili are not able to form colonies. Moreover, cells with deficient quorum sensing mechanism show similar aggregation as the wild-type bacteria. Therefore, our results demonstrate that pili provide an essential mechanism for colony formation, while additional chemical cues, for example quorum sensing, might be of secondary importance.

  12. Archaeal type IV pili and their involvement in biofilm formation

    Directory of Open Access Journals (Sweden)

    Rianne eEsquivel

    2015-03-01

    Full Text Available Type IV pili are ancient proteinaceous structures present on the cell surface of species in nearly all bacterial and archaeal phyla. These filaments are involved in a diverse array of critical cellular processes. While the core components of the pilus biosynthesis machinery are highly conserved, type IV pilins, the structural subunits of pili, share little sequence homology. However, the conserved structure of the signal peptides of these pilus subunits has allowed the development of prediction programs that accurately detect the processing sites recognized by bacterial and archaeal prepilin peptidases. Using these programs, the genomes of organisms from both prokaryotic domains have been shown to encode a diverse set of putative type IV pilins. Recently, in vivo studies in model archaea representing the euryarchaeal and crenarchaeal kingdoms confirmed that several of these pilins are incorporated into type IV adhesion pili. In addition to facilitating surface adhesion, these in vivo studies also showed that several predicted pilins are required for additional functions that are critical to biofilm formation. Examples include the subunits of Sulfolobus acidocaldarius Ups pili, which are induced by exposure to UV light and promote cell aggregation and conjugation, and a subset of the Haloferax volcanii adhesion pilins, which play a critical role in microcolony formation while other pilins inhibit this process. The recent discovery of novel pilin functions such as the ability of haloarchaeal adhesion pilins to regulate swimming motility rather than being unique to organisms that inhabit high salt environments may point to novel prokaryotic regulatory pathways. In this review, we will discuss recent advances in our understanding of the functional roles played by archaeal type IV adhesion pili and their subunits, with particular emphasis on their involvement in biofilm formation.

  13. Dynamic properties of bacterial pili measured by optical tweezers

    Science.gov (United States)

    Fallman, Erik G.; Andersson, Magnus J.; Schedin, Staffan S.; Jass, Jana; Uhlin, Bernt Eric; Axner, Ove

    2004-10-01

    The ability of uropathogenic Escherichia coli (UPEC) to cause urinary tract infections is dependent on their ability to colonize the uroepithelium. Infecting bacteria ascend the urethra to the bladder and then kidneys by attaching to the uroepithelial cells via the differential expression of adhesins. P pili are associated with pyelonephritis, the more severe infection of the kidneys. In order to find means to treat pyelonephritis, it is therefore of interest to investigate the properties P pili. The mechanical behavior of individual P pili of uropathogenic Escherichia coli has recently been investigated using optical tweezers. P pili, whose main part constitutes the PapA rod, composed of ~1000 PapA subunits in a helical arrangement, are distributed over the bacterial surface and mediate adhesion to host cells. We have earlier studied P pili regarding its stretching/elongation properties where we have found and characterized three different elongation regions, of which one constitute an unfolding of the quaternary (helical) structure of the PapA rod. It was shown that this unfolding takes place at an elongation independent force of 27 +/- 2 pN. We have also recently performed studies on its folding properties and shown that the unfolding/folding of the PapA rod is completely reversible. Here we present a study of the dynamical properties of the PapA rod. We show, among other things, that the unfolding force increases and that the folding force decreases with the speed of unfolding and folding respectively. Moreover, the PapA rod can be folded-unfolded a significant number of times without loosing its characteristics, a phenomenon that is believed to be important for the bacterium to keep close contact to the host tissue and consequently helps the bacterium to colonize the host tissue.

  14. Q pili enhance the attachment of Moraxella bovis to bovine corneas in vitro.

    Science.gov (United States)

    Ruehl, W W; Marrs, C; Beard, M K; Shokooki, V; Hinojoza, J R; Banks, S; Bieber, D; Mattick, J S

    1993-01-01

    Moraxella bovis, the causative agent of infectious bovine keratoconjunctivitis, exhibits several virulence factors, including pili, haemolysin, leukotoxin, and proteases. The pili are filamentous appendages which mediate bacterial adherence. Prior studies have shown that Q-piliated M. bovis Epp63 are more infectious and more pathogenic than I-piliated and non-piliated isogenic variants, suggesting that Q pili per se, or traits associated with Q-pilin expression, promote the early association of Q-piliated bacteria with bovine corneal tissue. In order to better evaluate the role of Q pili in M. bovis attachment, several M. bovis strains and a recombinant P. aeruginosa strain which elaborates M. bovis Q pili but not P. aeruginosa PAK pili, were evaluated using an in vitro corneal attachment assay. For each strain tested, piliated organisms attached better than non-piliated bacteria. M. bovis Epp63 Q-piliated bacteria adhered better than either the I-piliated or non-piliated isogenic variants. Finally, recombinant P. aeruginosa organisms elaborating M. bovis Q pili adhered better than the parent P. aeruginosa strain which did not produce M. bovis pili. These results indicate that the presence of pili, especially Q pili, enhances the attachment of bacteria to bovine cornea in vitro.

  15. A Geobacter sulfurreducens strain expressing pseudomonas aeruginosa type IV pili localizes OmcS on pili but is deficient in Fe(III) oxide reduction and current production.

    Science.gov (United States)

    Liu, Xing; Tremblay, Pier-Luc; Malvankar, Nikhil S; Nevin, Kelly P; Lovley, Derek R; Vargas, Madeline

    2014-02-01

    The conductive pili of Geobacter species play an important role in electron transfer to Fe(III) oxides, in long-range electron transport through current-producing biofilms, and in direct interspecies electron transfer. Although multiple lines of evidence have indicated that the pili of Geobacter sulfurreducens have a metal-like conductivity, independent of the presence of c-type cytochromes, this claim is still controversial. In order to further investigate this phenomenon, a strain of G. sulfurreducens, designated strain PA, was constructed in which the gene for the native PilA, the structural pilin protein, was replaced with the PilA gene of Pseudomonas aeruginosa PAO1. Strain PA expressed and properly assembled P. aeruginosa PilA subunits into pili and exhibited a profile of outer surface c-type cytochromes similar to that of a control strain expressing the G. sulfurreducens PilA. Surprisingly, the strain PA pili were decorated with the c-type cytochrome OmcS in a manner similar to the control strain. However, the strain PA pili were 14-fold less conductive than the pili of the control strain, and strain PA was severely impaired in Fe(III) oxide reduction and current production. These results demonstrate that the presence of OmcS on pili is not sufficient to confer conductivity to pili and suggest that there are unique structural features of the G. sulfurreducens PilA that are necessary for conductivity.

  16. Observation of bacterial type I pili extension and contraction under fluid flow.

    Directory of Open Access Journals (Sweden)

    Dilia E Rangel

    Full Text Available Type I pili are proteinaceous tethers that mediate bacterial adhesion of uropathogenic Escherichia coli to surfaces and are thought to help bacteria resist drag forces imparted by fluid flow via uncoiling of their quaternary structure. Uncoiling and recoiling have been observed in force spectroscopy experiments, but it is not clear if and how this process occurs under fluid flow. Here we developed an assay to study the mechanical properties of pili in a parallel plate flow chamber. We show that pili extend when attached E. coli bacteria are exposed to increasing shear stresses, that pili can help bacteria move against moderate fluid flows, and characterize two dynamic regimes of this displacement. The first regime is consistent with entropic contraction as modeled by a freely jointed chain, and the second with coiling of the quaternary structure of pili. These results confirm that coiling and uncoiling happen under flow but the observed dynamics are different from those reported previously. Using these results and those from previous studies, we review the mechanical properties of pili in the context of other elastic proteins such as the byssal threads of mussels. It has been proposed that the high extensibility of pili may help recruit more pili into tension and lower the force acting on each one by damping changes in force due to fluid flow. Our analysis of the mechanical properties suggests additional functions of pili; in particular, their extensibility may reduce tension by aligning pili with the direction of flow, and the uncoiled state of pili may complement uncoiling in regulating the force of the terminal adhesin.

  17. A structural basis for sustained bacterial adhesion: biomechanical properties of CFA/I pili.

    Science.gov (United States)

    Andersson, Magnus; Björnham, Oscar; Svantesson, Mats; Badahdah, Arwa; Uhlin, Bernt Eric; Bullitt, Esther

    2012-02-03

    Enterotoxigenic Escherichia coli (ETEC) are a major cause of diarrheal disease worldwide. Adhesion pili (or fimbriae), such as the CFA/I (colonization factor antigen I) organelles that enable ETEC to attach efficiently to the host intestinal tract epithelium, are critical virulence factors for initiation of infection. We characterized the intrinsic biomechanical properties and kinetics of individual CFA/I pili at the single-organelle level, demonstrating that weak external forces (7.5 pN) are sufficient to unwind the intact helical filament of this prototypical ETEC pilus and that it quickly regains its original structure when the force is removed. While the general relationship between exertion of force and an increase in the filament length for CFA/I pili associated with diarrheal disease is analogous to that of P pili and type 1 pili, associated with urinary tract and other infections, the biomechanical properties of these different pili differ in key quantitative details. Unique features of CFA/I pili, including the significantly lower force required for unwinding, the higher extension speed at which the pili enter a dynamic range of unwinding, and the appearance of sudden force drops during unwinding, can be attributed to morphological features of CFA/I pili including weak layer-to-layer interactions between subunits on adjacent turns of the helix and the approximately horizontal orientation of pilin subunits with respect to the filament axis. Our results indicate that ETEC CFA/I pili are flexible organelles optimized to withstand harsh motion without breaking, resulting in continued attachment to the intestinal epithelium by the pathogenic bacteria that express these pili. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. A Structural Basis for Sustained Bacterial Adhesion – Biomechanical Properties of CFA/I Pili

    Science.gov (United States)

    Andersson, Magnus; Björnham, Oscar; Svantesson, Mats; Badahdah, Arwa; Uhlin, Bernt Eric; Bullitt, Esther

    2012-01-01

    Enterotoxigenic Escherichia coli (ETEC) are a major cause of diarrheal disease worldwide. Adhesion pili (or fimbriae), such as the CFA/I (colonization factor antigen I) organelles that enable ETEC to attach efficiently to the host intestinal tract epithelium, are critical virulence factors for initiation of infection. We characterized at single organelle level the intrinsic biomechanical properties and kinetics of individual CFA/I pili, demonstrating that weak external forces (7.5 pN) are sufficient to unwind the intact helical filament of this prototypical ETEC pilus and that it quickly regains its original structure when the force is removed. While the general relationship between exertion of force and an increase in the filament length for CFA/I pili associated with diarrheal disease is analogous to that of P-pili and type 1 pili, associated with urinary tract and other infections, the biomechanical properties of these different pili differ in key quantitative details. Unique features of CFA/I pili, including the significantly lower force required for unwinding, the higher extension speed at which the pili enter a dynamic range of unwinding, and the appearance of sudden force drops during unwinding can be attributed to morphological features of CFA/I pili including weak layer-to-layer interactions between subunits on adjacent turns of the helix, and the approximately horizontal orientation of pilin subunits with respect to the filament axis. Our results indicate that ETEC CFA/I pili are flexible organelles optimized to withstand harsh motion without breaking, resulting in continued attachment to the intestinal epithelium by the pathogenic bacteria that express these pili. PMID:22178477

  19. Mitis group streptococci express variable pilus islet 2 pili.

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    Dorothea Zähner

    Full Text Available BACKGROUND: Streptococcus oralis, Streptococcus mitis, and Streptococcus sanguinis are members of the Mitis group of streptococci and agents of oral biofilm, dental plaque and infective endocarditis, disease processes that involve bacteria-bacteria and bacteria-host interactions. Their close relative, the human pathogen S. pneumoniae uses pilus-islet 2 (PI-2-encoded pili to facilitate adhesion to eukaryotic cells. METHODOLOGY/PRINCIPAL FINDINGS: PI-2 pilus-encoding genetic islets were identified in S. oralis, S. mitis, and S. sanguinis, but were absent from other isolates of these species. The PI-2 islets resembled the genetic organization of the PI-2 islet of S. pneumoniae, but differed in the genes encoding the structural pilus proteins PitA and PitB. Two and three variants of pitA (a pseudogene in S. pneumoniae and pitB, respectively, were identified that showed ≈20% difference in nucleotide as well as corresponding protein sequence. Species-independent combinations of pitA and pitB variants indicated prior intra- and interspecies horizontal gene transfer events. Polyclonal antisera developed against PitA and PitB of S. oralis type strain ATCC35037 revealed that PI-2 pili in oral streptococci were composed of PitA and PitB. Electronmicrographs showed pilus structures radiating >700 nm from the bacterial surface in the wild type strain, but not in an isogenic PI-2 deletion mutant. Anti-PitB-antiserum only reacted with pili containing the same PitB variant, whereas anti-PitA antiserum was cross-reactive with the other PitA variant. Electronic multilocus sequence analysis revealed that all PI-2-encoding oral streptococci were closely-related and cluster with non-PI-2-encoding S. oralis strains. CONCLUSIONS/SIGNIFICANCE: This is the first identification of PI-2 pili in Mitis group oral streptococci. The findings provide a striking example of intra- and interspecies horizontal gene transfer. The PI-2 pilus diversity provides a possible key to

  20. Probiotic Gut Microbiota Isolate Interacts with Dendritic Cells via Glycosylated Heterotrimeric Pili

    NARCIS (Netherlands)

    Tytgat, Hanne; Teijlingen, van N.H.; Sullan, R.M.; Douillard, F.P.; Rasinkangas, P.; Messing, M.; Reunanen, J.; Satokari, R.; Vanderleyden, J.; Dufrêne, Y.F.; Geijtenbeek, T.B.H.; Vos, de W.M.; Lebeer, S.

    2016-01-01

    Mapping of the microbial molecules underlying microbiota-host interactions is key to understand how microbiota preserve mucosal homeostasis. A pivotal family of such bacterial molecules are pili. Pili are proteinaceous cell wall appendages with a well-documented role in adhesion, whilst their role i

  1. Relevance of Aromatic Amino Acids for Electron Conduction along Geobacter Pili Protein

    Science.gov (United States)

    Adhikari, Ramesh; Malvankar, Nikhil; Tuominen, Mark; Lovley, Derek

    It has been proposed that the charge transport though Geobacter sulfurreducens pili protein occurs through the aromatic amino acids forming helical conducting chain within pili. X-ray studies of pili show that the aromatic amino acids are packed close enough (3-4 Å) for pi-stacking to occur. Conductivity of the pili network increases with lowering temperature indicating metallic-like transport mechanism. However due to the complexity of charge percolation path in 3D network, the intrinsic conductivity of an individual pili was not known. Here, we report transport measurements of individual pili of G. sulfurreducens. The conductivity, similar to that of organic polymers, shows that the pili may have implications in materials research. In addition, the conductivity value is sufficient to explain the respiration rate of the G. sulfurreducens. Further studies of pili from different natural and genetically modified species with varying amount of aromatic amino acid density demonstrate that it can play a decisive role on the magnitude of the conductivity. This research was supported by the Office of Naval Research (ONR) and National Science Foundation (NSF) Center for Hierarchical Manufacturing (CHM). Nikhil S. Malvankar holds a Career Award from the Burroughs Wellcome Fund.

  2. Molecular analysis of the UV-inducible pili operon from Sulfolobus acidocaldarius.

    Science.gov (United States)

    van Wolferen, Marleen; Ajon, Małgorzata; Driessen, Arnold J M; Albers, Sonja-Verena

    2013-12-01

    Upon ultraviolet (UV) stress, hyperthermophilic Sulfolobus species show a highly induced transcription of a gene cluster responsible for pili biogenesis: the UV-inducible pili operon (ups operon). This operon is involved in UV-induced pili assembly, cellular aggregation, and subsequent DNA exchange between cells. As the system increases the fitness of Sulfolobus cells after UV light exposure, we assume that transfer of DNA takes place in order to repair UV-induced DNA damages via homologous recombination. Here, we studied all genes present in the ups cluster via gene deletion analysis with a focus on UpsX, a protein that shows no identifiable functional domains. UspX does not seem to be structurally essential for UV-induced pili formation and cellular aggregation, but appears to be important for efficient DNA transfer. In addition, we could show that pilin subunits UpsA and UpsB probably both function as major pilin subunits in the ups pili.

  3. 78 FR 51208 - Request for Nominations for the Na Hoa Pili O Kaloko-Honokohau Advisory Commission

    Science.gov (United States)

    2013-08-20

    ... National Park Service Request for Nominations for the Na Hoa Pili O Kaloko-Honokohau Advisory Commission AGENCY: National Park Service, Interior. ACTION: Notice of Request for Nominations for the Na Hoa Pili O... Interior, proposes to appoint new members to the Na Hoa Pili O Kaloko-Honokohau (The Friends of...

  4. 76 FR 64103 - Request for Nominations for the Na Hoa Pili O Kaloko-Honokohau Advisory Commission

    Science.gov (United States)

    2011-10-17

    ... National Park Service Request for Nominations for the Na Hoa Pili O Kaloko-Honokohau Advisory Commission AGENCY: National Park Service, Interior. ACTION: Notice of request for nominations for the Na Hoa Pili O... Interior, proposes to appoint new members to the Na Hoa Pili O Kaloko-Honokohau (The Friends of...

  5. Purification, characterization, and pathogenicity of Moraxella bovis pili.

    Science.gov (United States)

    Ruehl, W W; Marrs, C F; Fernandez, R; Falkow, S; Schoolnik, G K

    1988-09-01

    Pilins composed of the alpha or beta pilins of Moraxella bovis strain Epp63 were purified, subjected to chemical or enzymatic cleavage, and the resulting fragments sequenced by automated Edman degradation. alpha Pilin was found to be a 155-amino-acid polypeptide with a single intramolecular disulfide bridge. The beta pilin amino acid sequence substantiated the previously reported structure derived from the beta pilin gene DNA sequence, and indicated that the alpha and beta pilins of this strain are approximately 70% homologous. DNA hybridization studies of genomic DNA from the alpha- and beta-piliated variants of strain Epp63 indicated that the expression of the two pilin types was governed by an oscillating mechanism of chromosomal rearrangement. The alpha and beta pili were evaluated serologically and found to exhibit approximately 50% shared antigenicity, indicating that regions of conserved and heterologous sequence specify both type-specific and crossreacting epitopes. The pathogenicity of the alpha- and beta-piliated variants was studied by ocular inoculation of calves eyes; beta-piliated organisms were significantly more infectious than alpha-piliated organisms, indicating that beta pili confer, or are associated with, a relative advantage during the first stages of ocular infection. Preliminary analysis of other M. bovis strains suggests that each strain produces two types of pilin, and that this property may be characteristic of the species.

  6. Mechanisms for Electron Transfer Through Pili to Fe(III) Oxide in Geobacter

    Energy Technology Data Exchange (ETDEWEB)

    Lovley, Derek R. [Univ. of Massachusetts, Amherst, MA (United States)

    2015-03-09

    The purpose of these studies was to aid the Department of Energy in its goal of understanding how microorganisms involved in the bioremediation of metals and radionuclides sustain their activity in the subsurface. This information is required in order to incorporate biological processes into decision making for environmental remediation and long-term stewardship of contaminated sites. The proposed research was designed to elucidate the mechanisms for electron transfer to Fe(III) oxides in Geobacter species because Geobacter species are abundant dissimilatory metal-reducing microorganisms in a diversity of sites in which uranium is undergoing natural attenuation via the reduction of soluble U(VI) to insoluble U(IV) or when this process is artificially stimulated with the addition of organic electron donors. This study investigated the novel, but highly controversial, concept that the final conduit for electron transfer to Fe(III) oxides are electrically conductive pili. The specific objectives were to: 1) further evaluate the conductivity along the pili of Geobacter sulfurreducens and related organisms; 2) determine the mechanisms for pili conductivity; and 3) investigate the role of pili in Fe(III) oxide reduction. The studies demonstrated that the pili of G. sulfurreducens are conductive along their length. Surprisingly, the pili possess a metallic-like conductivity similar to that observed in synthetic organic conducting polymers such as polyaniline. Detailed physical analysis of the pili, as well as studies in which the structure of the pili was genetically modified, demonstrated that the metallic-like conductivity of the pili could be attributed to overlapping pi-pi orbitals of aromatic amino acids. Other potential mechanisms for conductivity, such as electron hopping between cytochromes associated with the pili were definitively ruled out. Pili were also found to be essential for Fe(III) oxide reduction in G. metallireducens. Ecological studies demonstrated

  7. Uncoiling mechanism of Klebsiella pneumoniae type 3 pili measured by using optical tweezers

    Science.gov (United States)

    Chen, Feng-Jung; Chan, Chia-Han; Liu, Kuo-Liang; Huang, Ying-Jung; Peng, Hwei-Ling; Chang, Hwan-You; Yew, Tri-Rung; Hsu, Ken Y.; Hsu, Long

    2007-09-01

    Pili are bacterial appendages that play many important roles in bacterial behaviors, physiology and interaction with hosts. Via pili, bacteria are able to adhere to, migrate onto, and colonize on host cells, mechanically. Different from the most studied type 1 and P type pili, which are rigid and thick with an average of 6~7 nm in diameter, type 3 pili are relatively tiny (3-5 nm in diameter) and flexible, and their biophysical properties remains unclear. By using optical tweezers, we found that the elongation processes of type 3 pili are divided into three phases: (1) elastic elongation, (2) uncoiling elongation, and (3) intrinsic elongation, separately. Besides, the uncoiling force of the recombinant pili displayed on the surface of E. coli [pmrkABCD V1F] is measured 20 pN in average stronger than that of E. coli [pmrkABCD V1]. This suggests that pilin MrkF is involved in determining the mechanical properties of the type 3 pili.

  8. Pili canaliculi as manifestation of giant axonal neuropathy*

    Science.gov (United States)

    de Almeida Jr., Hiram Larangeira; Garcias, Gilberto; Silva, Ricardo Marques e; Batista, Stela Laner; Pasetto, Fernanda

    2016-01-01

    Giant axonal neuropathy is a rare autosomal recessive neurodegenerative disease. The condition is characterized by neurons with abnormally large axons due to intracellular filament accumulation. The swollen axons affect both the peripheral and central nervous system. A 6-year old female patient had been referred to a geneticist reporting problems with walking and hypotonia. At the age of 10, she became wheelchair dependent. Scanning electron microscopy of a curly hair classified it as pili canaliculi. GAN gene sequencing demonstrated mutation c.1456G>A (p.GLU486LYS). At the age of 12, the patient died due to respiratory complications. Dermatologists should be aware of this entity since hair changes are considered suggestive of GAN.

  9. Pili mediate specific adhesion of Streptococcus pyogenes to human tonsil and skin

    National Research Council Canada - National Science Library

    Abbot, Emily L; Smith, Wendy D; Siou, Gerard P. S; Chiriboga, Carlos; Smith, Rebecca J; Wilson, Janet A; Hirst, Barry H; Kehoe, Michael A

    2007-01-01

    ... such as Corynebacterium diphtheriae, Streptococcus agalacticae, S. pneumoniae and S. pyogenes. Using various ex vivo tissue and cellular models, here we show that pili mediate adhesion of serotype M1...

  10. Probiotic Gut Microbiota Isolate Interacts with Dendritic Cells via Glycosylated Heterotrimeric Pili.

    Directory of Open Access Journals (Sweden)

    Hanne L P Tytgat

    Full Text Available Mapping of the microbial molecules underlying microbiota-host interactions is key to understand how microbiota preserve mucosal homeostasis. A pivotal family of such bacterial molecules are pili. Pili are proteinaceous cell wall appendages with a well-documented role in adhesion, whilst their role in immune interaction with the host is less established. Gram-positive pili are often posttranslationally modified by sortase-specific cleavage reactions and the formation of intramolecular peptide bonds. Here we report glycosylation as a new level of posttranslational modification of sortase-dependent pili of a beneficial microbiota species and its role in immune modulation. We focused on the SpaCBA pili of the model probiotic and beneficial human gut microbiota isolate Lactobacillus rhamnosus GG. A unique combination of molecular techniques, nanoscale mechanical and immunological approaches led to the identification of mannose and fucose residues on the SpaCBA pili. These glycans on the pili are recognized by human dendritic cells via the C-type lectin receptor DC-SIGN, a key carbohydrate-dependent immune tailoring pattern recognition receptor. This specific lectin-sugar interaction is moreover of functional importance and modulated the cytokine response of dendritic cells. This provides insight into the direct role bacterial glycoproteins can play in the immunomodulation of the host. Modification of the complex heterotrimeric pili of a model probiotic and microbiota isolate with mannose and fucose is of importance for the functional interaction with the host immune lectin receptor DC-SIGN on human dendritic cells. Our findings shed light on the yet underappreciated role of glycoconjugates in bacteria-host interactions.

  11. A Structural Basis for Sustained Bacterial Adhesion – Biomechanical Properties of CFA/I Pili

    OpenAIRE

    Andersson, Magnus; Björnham, Oscar; Svantesson, Mats; Badahdah, Arwa; Uhlin, Bernt Eric; Bullitt, Esther

    2011-01-01

    Enterotoxigenic Escherichia coli (ETEC) are a major cause of diarrheal disease worldwide. Adhesion pili (or fimbriae), such as the CFA/I (colonization factor antigen I) organelles that enable ETEC to attach efficiently to the host intestinal tract epithelium, are critical virulence factors for initiation of infection. We characterized at single organelle level the intrinsic biomechanical properties and kinetics of individual CFA/I pili, demonstrating that weak external forces (7.5 pN) are suf...

  12. Pili mediate specific adhesion of Streptococcus pyogenes to human tonsil and skin.

    Science.gov (United States)

    Abbot, Emily L; Smith, Wendy D; Siou, Gerard P S; Chiriboga, Carlos; Smith, Rebecca J; Wilson, Janet A; Hirst, Barry H; Kehoe, Michael A

    2007-07-01

    Very little is known about the biological functions of pili that have recently been found to be expressed by important Gram-positive pathogens such as Corynebacterium diphtheriae, Streptococcus agalacticae, S. pneumoniae and S. pyogenes. Using various ex vivo tissue and cellular models, here we show that pili mediate adhesion of serotype M1 S. pyogenes strain SF370 to both human tonsil epithelium and primary human keratinocytes, which represent the two main sites of infection by this human-specific pathogen. Mutants lacking minor pilus subunits retained the ability to express cell-surface pili, but these were functionally defective. In contrast to above, pili were not required for S. pyogenes adhesion to either immortalized HEp-2 or A549 cells, highlighting an important limitation of these extensively used adhesion/invasion models. Adhering bacteria were internalized very effectively by both HEp-2 and A549 cells, but not by tonsil epithelium or primary keratinocytes. While pili acted as the primary adhesin, the surface M1 protein clearly enhanced adhesion to tonsil, but surprisingly, had the opposite effect on adhesion to keratinocytes. These studies provide clear evidence that S. pyogenes pili display an adhesive specificity for clinically relevant human tissues and are likely to play a critical role in the initial stages of infection.

  13. The Nanomechanical Properties of Lactococcus lactis Pili Are Conditioned by the Polymerized Backbone Pilin.

    Directory of Open Access Journals (Sweden)

    Mickaël Castelain

    Full Text Available Pili produced by Lactococcus lactis subsp. lactis are putative linear structures consisting of repetitive subunits of the major pilin PilB that forms the backbone, pilin PilA situated at the distal end of the pilus, and an anchoring pilin PilC that tethers the pilus to the peptidoglycan. We determined the nanomechanical properties of pili using optical-tweezers force spectroscopy. Single pili were exposed to optical forces that yielded force-versus-extension spectra fitted using the Worm-Like Chain model. Native pili subjected to a force of 0-200 pN exhibit an inextensible, but highly flexible ultrastructure, reflected by their short persistence length. We tested a panel of derived strains to understand the functional role of the different pilins. First, we found that both the major pilin PilB and sortase C organize the backbone into a full-length organelle and dictate the nanomechanical properties of the pili. Second, we found that both PilA tip pilin and PilC anchoring pilin were not essential for the nanomechanical properties of pili. However, PilC maintains the pilus on the bacterial surface and may play a crucial role in the adhesion- and biofilm-forming properties of L. lactis.

  14. Evidence for donor strand complementation in the biogenesis of Haemophilus influenzae haemagglutinating pili.

    Science.gov (United States)

    Krasan, G P; Sauer, F G; Cutter, D; Farley, M M; Gilsdorf, J R; Hultgren, S J; St Geme, J W

    2000-03-01

    Haemophilus influenzae haemagglutinating pili are surface appendages that promote attachment to host cells and facilitate respiratory tract colonization, an essential step in the pathogenesis of disease. In contrast to other well-characterized forms of pili, H. influenzae haemagglutinating pili are two-stranded helical structures. Nevertheless, haemagglutinating pili are assembled by a pathway that involves a periplasmic chaperone and an outer membrane usher, analogous to the prototype pathway involved in the biogenesis of Escherichia coli P pili. In this study, we performed site-directed mutagenesis of the H. influenzae HifB chaperone and HifA major pilus subunit at positions homologous to sites important for chaperone-subunit interactions and subunit oligomerization in P pili. Mutations at putative subunit binding pocket residues in HifB or at the penultimate tyrosine in HifA abolished formation of HifB-HifA periplasmic complexes, whereas mutations at the -14 glycine in HifA had no effect on HifB-HifA interactions but abrogated HifA oligomerization. To define further the constraints of the interaction between HifA and HifB, we examined the interchangeability of pilus gene cluster components from H. influenzae type b strain Eagan (hifA-hifEEag) and the related H. influenzae biogroup aegyptius strain F3031 (hifA-hifEF3031). Functional pili were assembled both with HifAEag and the strain F3031 gene cluster and with HifAF3031 and the strain Eagan gene cluster, underscoring the flexibility of the H. influenzae chaperone/usher pathway in incorporating HifA subunits with significant sequence diversity. To gain additional insight into the interactive surfaces of HifA and HifB, we aligned HifA sequences from 20 different strains and then modelled the HifA structure based on the recently crystallized PapD-PapK complex. Analysis of the resulting structure revealed high levels of sequence conservation in regions predicted to interact with HifB, and maximal sequence diversity

  15. Pili-driven surface motility of Myxococcus xanthus

    Science.gov (United States)

    Gibiansky, Maxsim; Hu, Wei; Zhao, Kun; Pan, Hongwei; Shi, Wenyuan; Dahmen, Karin; Wong, Gerard

    2012-02-01

    Myxococcus xanthus is a common, rod-shaped soil-dwelling bacterium with complex motility characteristics. In groups, M. xanthus bacteria can move via social ``S'' motility, in which the Type IV Pili (TFP) attach to secreted exopolysaccharides (EPS). We examine this motility mechanism using high-framerate video acquisition, taking data on individual bacteria at 400 frames per second; using particle tracking algorithms, we algorithmically reconstruct the bacterial trajectories. The motion of a single bacterium as it is pulled by its TFP through the EPS layer on the surface is not smooth, but instead displays distinct plateaus and slips, with a wide range of plateau and slip lengths. The distribution of slips exhibits power law scaling, consistent with a crackling noise model; crackling noise has previously been used to model nonbiological systems such as earthquake dynamics and Barkhausen noise. We show quantitative agreement between mean field friction models and observed bacterial dynamics. We demonstrate that the crackling noise behavior of M. xanthus is strongly dependent on the presence of EPS, but is unaffected by the chemotactic behavior of the bacterium; we also demonstrate velocity coupling between pairs of bacteria in the early stages of social motility.

  16. Extracellular reduction of uranium via Geobacter conductive pili as a protective cellular mechanism.

    Science.gov (United States)

    Cologgi, Dena L; Lampa-Pastirk, Sanela; Speers, Allison M; Kelly, Shelly D; Reguera, Gemma

    2011-09-13

    The in situ stimulation of Fe(III) oxide reduction by Geobacter bacteria leads to the concomitant precipitation of hexavalent uranium [U(VI)] from groundwater. Despite its promise for the bioremediation of uranium contaminants, the biological mechanism behind this reaction remains elusive. Because Fe(III) oxide reduction requires the expression of Geobacter's conductive pili, we evaluated their contribution to uranium reduction in Geobacter sulfurreducens grown under pili-inducing or noninducing conditions. A pilin-deficient mutant and a genetically complemented strain with reduced outer membrane c-cytochrome content were used as controls. Pili expression significantly enhanced the rate and extent of uranium immobilization per cell and prevented periplasmic mineralization. As a result, pili expression also preserved the vital respiratory activities of the cell envelope and the cell's viability. Uranium preferentially precipitated along the pili and, to a lesser extent, on outer membrane redox-active foci. In contrast, the pilus-defective strains had different degrees of periplasmic mineralization matching well with their outer membrane c-cytochrome content. X-ray absorption spectroscopy analyses demonstrated the extracellular reduction of U(VI) by the pili to mononuclear tetravalent uranium U(IV) complexed by carbon-containing ligands, consistent with a biological reduction. In contrast, the U(IV) in the pilin-deficient mutant cells also required an additional phosphorous ligand, in agreement with the predominantly periplasmic mineralization of uranium observed in this strain. These findings demonstrate a previously unrecognized role for Geobacter conductive pili in the extracellular reduction of uranium, and highlight its essential function as a catalytic and protective cellular mechanism that is of interest for the bioremediation of uranium-contaminated groundwater.

  17. Multiscale modeling of bacterial colonies: how pili mediate the dynamics of single cells and cellular aggregates

    Science.gov (United States)

    Pönisch, Wolfram; Weber, Christoph A.; Juckeland, Guido; Biais, Nicolas; Zaburdaev, Vasily

    2017-01-01

    Neisseria gonorrhoeae is the causative agent of one of the most common sexually transmitted diseases, gonorrhea. Over the past two decades there has been an alarming increase of reported gonorrhea cases where the bacteria were resistant to the most commonly used antibiotics thus prompting for alternative antimicrobial treatment strategies. The crucial step in this and many other bacterial infections is the formation of microcolonies, agglomerates consisting of up to several thousands of cells. The attachment and motility of cells on solid substrates as well as the cell-cell interactions are primarily mediated by type IV pili, long polymeric filaments protruding from the surface of cells. While the crucial role of pili in the assembly of microcolonies has been well recognized, the exact mechanisms of how they govern the formation and dynamics of microcolonies are still poorly understood. Here, we present a computational model of individual cells with explicit pili dynamics, force generation and pili-pili interactions. We employ the model to study a wide range of biological processes, such as the motility of individual cells on a surface, the heterogeneous cell motility within the large cell aggregates, and the merging dynamics and the self-assembly of microcolonies. The results of numerical simulations highlight the central role of pili generated forces in the formation of bacterial colonies and are in agreement with the available experimental observations. The model can quantify the behavior of multicellular bacterial colonies on biologically relevant temporal and spatial scales and can be easily adjusted to include the geometry and pili characteristics of various bacterial species. Ultimately, the combination of the microbiological experimental approach with the in silico model of bacterial colonies might provide new qualitative and quantitative insights on the development of bacterial infections and thus pave the way to new antimicrobial treatments.

  18. Vibrio cholerae use pili and flagella synergistically to effect motility switching and conditional surface attachment

    Science.gov (United States)

    Utada, Andrew S.; Bennett, Rachel R.; Fong, Jiunn C. N.; Gibiansky, Maxsim L.; Yildiz, Fitnat H.; Golestanian, Ramin; Wong, Gerard C. L.

    2014-09-01

    We show that Vibrio cholerae, the causative agent of cholera, use their flagella and mannose-sensitive hemagglutinin (MSHA) type IV pili synergistically to switch between two complementary motility states that together facilitate surface selection and attachment. Flagellar rotation counter-rotates the cell body, causing MSHA pili to have periodic mechanical contact with the surface for surface-skimming cells. Using tracking algorithms at 5 ms resolution we observe two motility behaviours: ‘roaming', characterized by meandering trajectories, and ‘orbiting’, characterized by repetitive high-curvature orbits. We develop a hydrodynamic model showing that these phenotypes result from a nonlinear relationship between trajectory shape and frictional forces between pili and the surface: strong pili-surface interactions generate orbiting motion, increasing the local bacterial loiter time. Time-lapse imaging reveals how only orbiting mode cells can attach irreversibly and form microcolonies. These observations suggest that MSHA pili are crucial for surface selection, irreversible attachment, and ultimately microcolony formation.

  19. Visualization of charge propagation along individual pili proteins using ambient electrostatic force microscopy

    Science.gov (United States)

    Malvankar, Nikhil S.; Yalcin, Sibel Ebru; Tuominen, Mark T.; Lovley, Derek R.

    2014-12-01

    The nanoscale imaging of charge flow in proteins is crucial to understanding several life processes, including respiration, metabolism and photosynthesis. However, existing imaging methods are only effective under non-physiological conditions or are limited to photosynthetic proteins. Here, we show that electrostatic force microscopy can be used to directly visualize charge propagation along pili of Geobacter sulfurreducens with nanometre resolution and under ambient conditions. Charges injected at a single point into individual, untreated pili, which are still attached to cells, propagated over the entire filament. The mobile charge density in the pili, as well as the temperature and pH dependence of the charge density, were similar to those of carbon nanotubes and other organic conductors. These findings, coupled with a lack of charge propagation in mutated pili that were missing key aromatic amino acids, suggest that the pili of G. sulfurreducens function as molecular wires with transport via delocalized charges, rather than the hopping mechanism that is typical of biological electron transport.

  20. Strain-specific differences in pili formation and the interaction of Corynebacterium diphtheriae with host cells

    Directory of Open Access Journals (Sweden)

    Hensel Michael

    2010-10-01

    Full Text Available Abstract Background Corynebacterium diphtheriae, the causative agent of diphtheria, is well-investigated in respect to toxin production, while little is known about C. diphtheriae factors crucial for colonization of the host. In this study, we investigated strain-specific differences in adhesion, invasion and intracellular survival and analyzed formation of pili in different isolates. Results Adhesion of different C. diphtheriae strains to epithelial cells and invasion of these cells are not strictly coupled processes. Using ultrastructure analyses by atomic force microscopy, significant differences in macromolecular surface structures were found between the investigated C. diphtheriae strains in respect to number and length of pili. Interestingly, adhesion and pili formation are not coupled processes and also no correlation between invasion and pili formation was found. Using RNA hybridization and Western blotting experiments, strain-specific pili expression patterns were observed. None of the studied C. diphtheriae strains had a dramatic detrimental effect on host cell viability as indicated by measurements of transepithelial resistance of Detroit 562 cell monolayers and fluorescence microscopy, leading to the assumption that C. diphtheriae strains might use epithelial cells as an environmental niche supplying protection against antibodies and macrophages. Conclusions The results obtained suggest that it is necessary to investigate various isolates on a molecular level to understand and to predict the colonization process of different C. diphtheriae strains.

  1. Biofilm formation by Pseudomonas aeruginosa wild type, flagella and type IV pili mutants

    DEFF Research Database (Denmark)

    Klausen, M.; Heydorn, Arne; Ragas, Paula Cornelia

    2003-01-01

    Biofilm formation by Gfp-tagged Pseudomonas aeruginosa PAO1 wild type, flagella and type IV pili mutants in flow chambers irrigated with citrate minimal medium was characterized by the use of confocal laser scanning microscopy and comstat image analysis. Flagella and type IV pili were not necessary...... for P. aeruginosa initial attachment or biofilm formation, but the cell appendages had roles in biofilm development, as wild type, flagella and type IV pili mutants formed biofilms with different structures. Dynamics and selection during biofilm formation were investigated by tagging the wild type...... and flagella/type IV mutants with Yfp and Cfp and performing time-lapse confocal laser scanning microscopy in mixed colour biofilms. The initial microcolony formation occurred by clonal growth, after which wild-type P. aeruginosa bacteria spread over the substratum by means of twitching motility. The wild...

  2. Infectious bovine keratoconjunctivitis: enhancement of Moraxella bovis pili immunogenicity with diphtheria-tetanus toxoids and pertussis vaccine.

    Science.gov (United States)

    Pugh, G W; Kopecky, K E; McDonald, T J

    1984-04-01

    A study was conducted to determine whether diphtheria-tetanus-toxoids and pertussis vaccine (DPT) would enhance the immunogenicity of homologous Moraxella bovis pili fractions. Thirty-six calves were divided into 4 groups (I, II, III, and IV) of 9 calves each. Calves in group I were not vaccinated and served as controls. Calves in group II were vaccinated with pili fractions only. Calves in group III were vaccinated with DPT only. Calves in group IV were vaccinated with DPT and pili. Vaccination consisted of 2 inoculations, 21 days apart. Fourteen days after the last vaccinal inoculation was done, the eyes of all calves were exposed to a hemolytic homologous strain of M bovis. The percentage of eyes with disease was significantly less in calves given DPT and pili (P less than 0.001) and calves given pili only (P less than 0.05) than in calves given DPT only or nonvaccinated calves. The lesions were less severe in calves vaccinated with pili only than in calves not vaccinated with pili. Serologic results also showed a positive relationship between the development of serum antibodies against pili and immunity. The results indicate that DPT enhanced the immune response and if used as an adjuvant, might be useful in the development of a vaccine against infectious bovine keratoconjunctivitis.

  3. 77 FR 66864 - Notice of November 15, 2012, Meeting for Na Hoa Pili O Kaloko-Honokohau National Historical Park...

    Science.gov (United States)

    2012-11-07

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR National Park Service Notice of November 15, 2012, Meeting for Na Hoa Pili O Kaloko- Honokohau National.... SUMMARY: This notice sets forth the date of the November 15, 2012, meeting of the Na Hoa Pili O...

  4. Impairment of the biomechanical compliance of P pili: a novel means of inhibiting uropathogenic bacterial infections?

    Science.gov (United States)

    Klinth, Jeanna E; Pinkner, Jerome S; Hultgren, Scott J; Almqvist, Fredrik; Uhlin, Bernt Eric; Axner, Ove

    2012-03-01

    Gram-negative bacteria often initiate their colonization by use of extended attachment organelles, so called pili. When exposed to force, the rod of helix-like pili has been found to be highly extendable, mainly attributed to uncoiling and recoiling of its quaternary structure. This provides the bacteria with the ability to redistribute an external force among a multitude of pili, which enables them to withstand strong rinsing flows, which, in turn, facilitates adherence and colonization processes critical to virulence. Thus, pili fibers are possible targets for novel antibacterial agents. By use of a substance that compromises compliance of the pili, the ability of bacteria to redistribute external forces can be impaired, so they will no longer be able to resist strong urine flow and thus be removed from the host. It is possible such a substance can serve as an alternative to existing antibiotics in the future or be a part of a multi-drug. In this work we investigated whether it is possible to achieve this by targeting the recoiling process. The test substance was purified PapD. The effect of PapD on the compliance of P pili was assessed at the single organelle level by use of force-measuring optical tweezers. We showed that the recoiling process, and thus the biomechanical compliance, in particular the recoiling process, can be impaired by the presence of PapD. This leads to a new concept in the search for novel drug candidates combating uropathogenic bacterial infections--"coilicides", targeting the subunits of which the pilus rod is composed.

  5. Multiple roles of Pseudomonas aeruginosa TBCF10839 PilY1 in motility, transport and infection

    DEFF Research Database (Denmark)

    Bohn, Yu-Sing Tammy; Brandes, Gudrun; Rakhimova, Elza

    2009-01-01

    Polymorphonuclear neutrophils are the most important mammalian host defence cells against infections with Pseudomonas aeruginosa. Screening of a signature tagged mutagenesis library of the non-piliated P. aeruginosa strain TBCF10839 uncovered that transposon inactivation of its pilY1 gene rendere...

  6. The Virulence Regulator Rns Activates the Expression of CS14 Pili

    Directory of Open Access Journals (Sweden)

    Maria Del Rocio Bodero

    2016-12-01

    Full Text Available Although many viral and bacterial pathogens cause diarrhea, enterotoxigenic E. coli (ETEC is one of the most frequently encountered in impoverished regions where it is estimated to kill between 300,000 and 700,000 children and infants annually. Critical ETEC virulence factors include pili which mediate the attachment of the pathogen to receptors in the intestinal lumen. In this study we show that the ETEC virulence regulator Rns positively regulates the expression of CS14 pili. Three Rns binding sites were identified upstream of the CS14 pilus promoter centered at −34.5, −80.5, and −155.5 relative to the Rns-dependent transcription start site. Mutagenesis of the promoter proximal site significantly decreased expression from the CS14 promoter. In contrast, the contribution of Rns bound at the promoter distal site was negligible and largely masked by occupancy of the promoter proximal site. Unexpectedly, Rns bound at the site centered at −80.5 had a slight but statistically significant inhibitory effect upon the pilin promoter. Nevertheless, this weak inhibitory effect was not sufficient to overcome the substantial promoter activation from Rns bound to the promoter proximal site. Thus, CS14 pili belong to a group of pili that depend upon Rns for their expression.

  7. Complete Genome Sequence of Pseudomonas aeruginosa Podophage MPK7, Which Requires Type IV Pili for Infection.

    Science.gov (United States)

    Bae, Hee-Won; Cho, You-Hee

    2013-10-10

    We report the complete genome sequence of Pseudomonas aeruginosa podophage MPK7. It displays synteny to the P. aeruginosa phages of the Phikmvlikevirus genus, which includes phiKMV and LKA1. MPK7 requires type IV pili (TFP) for infection, suggesting the role of functional TFP as the receptor for this phage genus.

  8. Force measuring optical tweezers system for long time measurements of P pili stability

    Science.gov (United States)

    Andersson, Magnus; Fällman, Erik; Uhlin, Bernt Eric; Axner, Ove

    2006-02-01

    A force-measuring optical tweezers instrumentation and long time measurements of the elongation and retraction of bacterial fimbriae from Uropathogenic E. coli (UPEC) under strain are presented. The instrumentation is presented in some detail. Special emphasis is given to measures taken to reduce the influence of noise and drifts in the system and from the surrounding, which makes long term force measurements possible. Individual P pili from UPEC bacteria were used as a biological model system for repetitive unfolding and refolding cycles of bacterial fimbriae under equilibrium conditions. P pili have evolved into a three-dimensional helix-like structure, the PapA rod, that can be successively and significantly elongated and/or unfolded when exposed to external forces. The instrumentation is used for characterization of the force-vs.-elongation response of the PapA rod of individual P pili, with emphasis on the long time stability of the forced unfolding and refolding of the helical structure of the PapA rod. The results show that the PapA rod is capable of withstanding extensive strain, leading to a complete unfolding of the helical structure, repetitive times during the life cycle of a bacterium without any noticeable alteration of the mechanical properties of the P pili. This function is believed to be importance for UPEC bacteria in vivo since it provides a close contact to a host cell (which is an initial step of invasion) despite urine cleaning attempts.

  9. UV-inducible cellular aggregation of the hyperthermophilic archaeon Sulfolobus solfataricus is mediated by pili formation

    NARCIS (Netherlands)

    Froels, Sabrina; Ajon, Malgorzata; Wagner, Michaela; Teichmann, Daniela; Zolghadr, Behnam; Folea, Mihaela; Boekema, Egbert J.; Driessen, Arnold J. M.; Schleper, Christa; Albers, Sonja-Verena

    2008-01-01

    The hyperthermophilic archaeon Sulfolobus solfataricus has been shown to exhibit a complex transcriptional response to UV irradiation involving 55 genes. Among the strongest UV-induced genes was a putative pili biogenesis operon encoding a potential secretion ATPase, two pre-pilins, a putative trans

  10. A Moraxella bovis pili vaccine produced by recombinant DNA technology for the prevention of infectious bovine keratoconjunctivitis.

    Science.gov (United States)

    Lepper, A W; Elleman, T C; Hoyne, P A; Lehrbach, P R; Atwell, J L; Schwartzkoff, C L; Egerton, J R; Tennent, J M

    1993-07-01

    Pili (fimbriae) were prepared from Moraxella bovis strain Dalton 2d (Dal2d) and from a derivative of Pseudomonas aeruginosa K/2PfS that contained a plasmid-borne Dal2d pilin gene and produced pili having serogroup-specific identity to Dal2d. Nine calves were vaccinated with two doses each of 30 micrograms authentic M. bovis Dal2d pili in oil adjuvant and 10 calves were vaccinated with a similar dose of P. aeruginosa-derived Dal2d pili in the same formulation. All 19 calves and 10 non-vaccinated controls were challenged by instillation of 1 x 10(9) virulent M. bovis Dal2d cells into both conjunctival sacs 19 days after the second vaccine dose. The serological response to vaccination and the degree of protection against experimentally induced infectious bovine keratoconjunctivitis (IBK) were assessed. None of the nine calves vaccinated with authentic M. bovis Dal2d pili developed IBK while two of those vaccinated with P. aeruginosa-derived Dal2d pili developed lesions which accounted for a mean group lesion score of 0.3. In contrast, 9 of the 10 non-vaccinated calves developed IBK lesions, the majority of which were progressive, required early treatment and accounted for a mean group lesion score of 1.5. These results demonstrate the potential of a relatively low dose of pili produced by recombinant DNA technology for development of an effective vaccine against IBK.

  11. Highly conserved type 1 pili promote enterotoxigenic E. coli pathogen-host interactions.

    Directory of Open Access Journals (Sweden)

    Alaullah Sheikh

    2017-05-01

    Full Text Available Enterotoxigenic Escherichia coli (ETEC, defined by their elaboration of heat-labile (LT and/or heat-stable (ST enterotoxins, are a common cause of diarrheal illness in developing countries. Efficient delivery of these toxins requires ETEC to engage target host enterocytes. This engagement is accomplished using a variety of pathovar-specific and conserved E. coli adhesin molecules as well as plasmid encoded colonization factors. Some of these adhesins undergo significant transcriptional modulation as ETEC encounter intestinal epithelia, perhaps suggesting that they cooperatively facilitate interaction with the host. Among genes significantly upregulated on cell contact are those encoding type 1 pili. We therefore investigated the role played by these pili in facilitating ETEC adhesion, and toxin delivery to model intestinal epithelia. We demonstrate that type 1 pili, encoded in the E. coli core genome, play an essential role in ETEC virulence, acting in concert with plasmid-encoded pathovar specific colonization factor (CF fimbriae to promote optimal bacterial adhesion to cultured intestinal epithelium (CIE and to epithelial monolayers differentiated from human small intestinal stem cells. Type 1 pili are tipped with the FimH adhesin which recognizes mannose with stereochemical specificity. Thus, enhanced production of highly mannosylated proteins on intestinal epithelia promoted FimH-mediated ETEC adhesion, while conversely, interruption of FimH lectin-epithelial interactions with soluble mannose, anti-FimH antibodies or mutagenesis of fimH effectively blocked ETEC adhesion. Moreover, fimH mutants were significantly impaired in delivery of both heat-stable and heat-labile toxins to the target epithelial cells in vitro, and these mutants were substantially less virulent in rabbit ileal loop assays, a classical model of ETEC pathogenesis. Collectively, our data suggest that these highly conserved pili play an essential role in virulence of these

  12. The three-dimensional structure of CFA/I adhesion pili: traveler's diarrhea bacteria hang on by a spring.

    Science.gov (United States)

    Mu, Xiang-Qi; Savarino, Stephen J; Bullitt, Esther

    2008-02-22

    To survive the harsh environment of a churning intestinal tract, bacteria attach to the host epithelium via thin fibers called pili (or fimbriae). Enterotoxigenic Escherichia coli bacteria expressing colonization factor antigen I (CFA/I) pili and related pili are the most common known bacterial cause of diarrheal disease, including traveler's diarrhea. CFA/I pili, assembled via the alternate chaperone pathway, are essential for binding and colonization of the small bowel by these pathogenic bacteria. Herein, we elucidate unique structural features of CFA/I pili that appear to optimize their function as bacterial tethers in the intestinal tract. Using transmission electron microscopy of negatively stained samples in combination with iterative three-dimensional helical reconstruction methods for image processing, we determined the structure of the CFA/I pilus filament. Our results indicate that strong end-to-end protein interactions and weak interactions between the coils of a sturdy spring-like helix provide the combination of strength, stability, and flexibility required to sustain bacterial adhesion and incite intestinal disease. We propose that CFA/I pili behave like a spring to maintain attachment to the gut lining during vortex mixing and downward flow of the intestinal contents, thereby persisting long enough for these bacteria to colonize the host epithelium and cause enteric disease.

  13. Low Energy Atomic Models Suggesting a Pilus Structure that could Account for Electrical Conductivity of Geobacter sulfurreducens Pili.

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    Xiao, Ke; Malvankar, Nikhil S; Shu, Chuanjun; Martz, Eric; Lovley, Derek R; Sun, Xiao

    2016-03-22

    The metallic-like electrical conductivity of Geobacter sulfurreducens pili has been documented with multiple lines of experimental evidence, but there is only a rudimentary understanding of the structural features which contribute to this novel mode of biological electron transport. In order to determine if it was feasible for the pilin monomers of G. sulfurreducens to assemble into a conductive filament, theoretical energy-minimized models of Geobacter pili were constructed with a previously described approach, in which pilin monomers are assembled using randomized structural parameters and distance constraints. The lowest energy models from a specific group of predicted structures lacked a central channel, in contrast to previously existing pili models. In half of the no-channel models the three N-terminal aromatic residues of the pilin monomer are arranged in a potentially electrically conductive geometry, sufficiently close to account for the experimentally observed metallic like conductivity of the pili that has been attributed to overlapping pi-pi orbitals of aromatic amino acids. These atomic resolution models capable of explaining the observed conductive properties of Geobacter pili are a valuable tool to guide further investigation of the metallic-like conductivity of the pili, their role in biogeochemical cycling, and applications in bioenergy and bioelectronics.

  14. Chaperone-Usher Pili Loci of Colonization Factor-Negative Human Enterotoxigenic Escherichia coli

    Science.gov (United States)

    Del Canto, Felipe; O'Ryan, Miguel; Pardo, Mirka; Torres, Alexia; Gutiérrez, Daniela; Cádiz, Leandro; Valdés, Raul; Mansilla, Aquiles; Martínez, Rodrigo; Hernández, Daniela; Caro, Benjamin; Levine, Myron M.; Rasko, David A.; Hill, Christopher M.; Pop, Mihai; Stine, O. Colin; Vidal, Roberto

    2017-01-01

    Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrhea worldwide. Among the 25 different ETEC adhesins, 22 are known as “colonization factors” (CFs), of which 17 are assembled by the chaperone-usher (CU) mechanism. Currently, there is no preventive therapy against ETEC, and CFs have been proposed as components for vaccine development. However, studies of diarrhea-causing ETEC strains worldwide indicate that between 15 and 50% of these are negative for known CFs, hindering the selection of the most widespread structures and suggesting that unknown adhesins remain to be identified. Here, we report the result of a comprehensive analysis of 35 draft genomes of ETEC strains which do not carry known adhesin genes; our goal was to find new CU pili loci. The phylogenetic profiles and serogroups of these strains were highly diverse, a majority of which produced only the heat-labile toxin. We identified 10 pili loci belonging to CU families β (1 locus), γ2 (7 loci), κ (1 locus), and π (1 locus), all of which contained the required number of open reading frames (ORFs) to encode functional structures. Three loci were variants of previously-known clusters, three had been only-partially described, and four are novel loci. Intra-loci genetic variability identified would allow the synthesis of up to 14 different structures. Clusters of putative γ2-CU pili were most common (23 strains), followed by putative β-CU pili (12 strains), which have not yet been fully characterized. Overall, our findings significantly increase the number of ETEC adhesion genes associated with human infections. PMID:28111618

  15. Structural characterization of CFA/III and Longus type IVb pili from enterotoxigenic Escherichia coli.

    Science.gov (United States)

    Kolappan, Subramaniapillai; Roos, Justin; Yuen, Alex S W; Pierce, Owen M; Craig, Lisa

    2012-05-01

    The type IV pili are helical filaments found on many Gram-negative pathogenic bacteria, with multiple diverse roles in pathogenesis, including microcolony formation, adhesion, and twitching motility. Many pathogenic enterotoxigenic Escherichia coli (ETEC) isolates express one of two type IV pili belonging to the type IVb subclass: CFA/III or Longus. Here we show a direct correlation between CFA/III expression and ETEC aggregation, suggesting that these pili, like the Vibrio cholerae toxin-coregulated pili (TCP), mediate microcolony formation. We report a 1.26-Å resolution crystal structure of CofA, the major pilin subunit from CFA/III. CofA is very similar in structure to V. cholerae TcpA but possesses a 10-amino-acid insertion that replaces part of the α2-helix with an irregular loop containing a 3(10)-helix. Homology modeling suggests a very similar structure for the Longus LngA pilin. A model for the CFA/III pilus filament was generated using the TCP electron microscopy reconstruction as a template. The unique 3(10)-helix insert fits perfectly within the gap between CofA globular domains. This insert, together with differences in surface-exposed residues, produces a filament that is smoother and more negatively charged than TCP. To explore the specificity of the type IV pilus assembly apparatus, CofA was expressed heterologously in V. cholerae by replacing the tcpA gene with that of cofA within the tcp operon. Although CofA was synthesized and processed by V. cholerae, no CFA/III filaments were detected, suggesting that the components of the type IVb pilus assembly system are highly specific to their pilin substrates.

  16. Pili-mediated Interactions between Neisseria Gonorrhoeae Bacteria are the Driving Mechanism of Microcolony Merging

    Science.gov (United States)

    Poenisch, Wolfram; Weber, Christoph; Alzurqa, Khaled; Nasrollahi, Hadi; Biais, Nicolas; Zaburdaev, Vasily; Collective Dynamics of Cells Team; Mechano-Micro-Biology Lab Team

    2015-03-01

    During the early infection with Neisseria gonorrhoeae the bacteria form microcolonies consisting of a few hundreds to a few thousands of cells. The formation of colonies is mediated by type IV pili, thin and long filaments that are also involved in the motion of single cells over a substrate. A related process causes attractive cell-cell-interactions. While the motion of single cells has been extensively studied during the past years, the physical principles driving the growth of these colonies are poorly understood. One key mechanism of colony growth is coalescence of smaller colonies. Therefore we experimentally examine the process of merging of two Neisseria gonorrhoeae colonies. We develop a theoretical microscopic model of single cells interacting solely by their pili. The experimental data and the results obtained from our model are in excellent quantitative agreement. We observe a fast initial approach of the two merging colonies within a few minutes, that is followed by a slow relaxation of the colony shape with a characteristic time of several hours. These findings suggest that pili-mediated interactions are the primary driving mechanism of the microcolony merging process.

  17. Rigid multibody simulation of a helix-like structure: the dynamics of bacterial adhesion pili.

    Science.gov (United States)

    Zakrisson, Johan; Wiklund, Krister; Servin, Martin; Axner, Ove; Lacoursière, Claude; Andersson, Magnus

    2015-07-01

    We present a coarse-grained rigid multibody model of a subunit assembled helix-like polymer, e.g., adhesion pili expressed by bacteria, that is capable of describing the polymer's force-extension response. With building blocks representing individual subunits, the model appropriately describes the complex behavior of pili expressed by the gram-negative uropathogenic Escherichia coli bacteria under the action of an external force. Numerical simulations show that the dynamics of the model, which include the effects of both unwinding and rewinding, are in good quantitative agreement with the characteristic force-extension response as observed experimentally for type 1 and P pili. By tuning the model, it is also possible to reproduce the force-extension response in the presence of anti-shaft antibodies, which dramatically changes the mechanical properties. Thus, the model and results in this work give enhanced understanding of how a pilus unwinds under the action of external forces and provide a new perspective of the complex bacterial adhesion processes.

  18. In vivo expression and variation of Escherichia coli type 1 and P pili in the urine of adults with acute urinary tract infections.

    Science.gov (United States)

    Kisielius, P. V.; Schwan, W. R.; Amundsen, S. K.; Duncan, J. L.; Schaeffer, A. J.

    1989-01-01

    In vivo expression of pili by Escherichia coli in the urine of 41 adults with lower urinary tract infections was analyzed by immunostaining with polyclonal antiserum to type 1 and P pili. Type 1 pili were detected in 31 of 41 urine specimens, while P pili were detected in 6 of 18 specimens. The piliation status of bacterial populations in urine was heterogeneous, varying from predominantly piliated to a mixture of piliated and nonpiliated cells. Bacteria frequently adhered to exfoliated uroepithelial cells and leukocytes in urine. Expression of pili in vivo did not always correlate with the hemagglutination phenotype after growth in vitro. Strains isolated from different sites in the urogenital tract of two individuals showed phenotypic variation in the state of piliation. The results demonstrate that E. coli type 1 and P pili are expressed and are subject to variation in vivo during acute urinary tract infections in adults. Images PMID:2566580

  19. Mutations in the Gene Encoding the Ancillary Pilin Subunit of the Streptococcus suis srtF Cluster Result in Pili Formed by the Major Subunit Only

    Science.gov (United States)

    Fittipaldi, Nahuel; Takamatsu, Daisuke; la Cruz Domínguez-Punaro, María de; Lecours, Marie-Pier; Montpetit, Diane; Osaki, Makoto; Sekizaki, Tsutomu; Gottschalk, Marcelo

    2010-01-01

    Pili have been shown to contribute to the virulence of different Gram-positive pathogenic species. Among other critical steps of bacterial pathogenesis, these structures participate in adherence to host cells, colonization and systemic virulence. Recently, the presence of at least four discrete gene clusters encoding putative pili has been revealed in the major swine pathogen and emerging zoonotic agent Streptococcus suis. However, pili production by this species has not yet been demonstrated. In this study, we investigated the functionality of one of these pili clusters, known as the srtF pilus cluster, by the construction of mutant strains for each of the four genes of the cluster as well as by the generation of antibodies against the putative pilin subunits. Results revealed that the S. suis serotype 2 strain P1/7, as well as several other highly virulent invasive S. suis serotype 2 isolates express pili from this cluster. However, in most cases tested, and as a result of nonsense mutations at the 5′ end of the gene encoding the minor pilin subunit (a putative adhesin), pili were formed by the major pilin subunit only. We then evaluated the role these pili play in S. suis virulence. Abolishment of the expression of srtF cluster-encoded pili did not result in impaired interactions of S. suis with porcine brain microvascular endothelial cells. Furthermore, non-piliated mutants were as virulent as the wild type strain when evaluated in a murine model of S. suis sepsis. Our results show that srtF cluster-encoded, S. suis pili are atypical compared to other Gram-positive pili. In addition, since the highly virulent strains under investigation are unlikely to produce other pili, our results suggest that pili might be dispensable for critical steps of the S. suis pathogenesis of infection. PMID:20052283

  20. Pili play an important role in enhancing the bacterial clearance from the middle ear in a mouse model of acute otitis media with Moraxella catarrhalis.

    Science.gov (United States)

    Kawano, Toshiaki; Hirano, Takashi; Kodama, Satoru; Mitsui, Marcelo Takahiro; Ahmed, Kamruddin; Nishizono, Akira; Suzuki, Masashi

    2013-03-01

    Moraxella catarrhalis is a Gram-negative aerobic diplococcus that is currently the third most frequent cause of bacterial acute otitis media (AOM) in children. In this study, we developed an experimental murine AOM model by inoculating M. catarrhalis in the middle ear bulla and studied the local response to this inoculation, and modulation of its course by the pili of M. catarrhalis. The pili-positive and pili-negative M. catarrhalis showed differences in bacterial clearance and infiltration of inflammatory cells in the middle ear. Pili-negative M. catarrhalis induced a more delayed and prolonged immune response in the middle ear than that of pili-positive M. catarrhalis. TLR2, -4, -5 and -9 mRNA expression was upregulated in neutrophils that infiltrated the middle ear cavity during AOM caused by both pili-positive and pili-negative bacteria. TLR5 mRNA expression and TLR5 protein in the neutrophils were induced more robustly by pili-positive M. catarrhalis. This immune response is likely to be related to neutrophil function such as toll-like 5-dependent phagocytosis. Our results show that mice may provide a useful AOM model for studying the role of M. catarrhalis. Furthermore, we show that pili play an important role in enhancing M. catarrhalis clearance from the middle ear that is probably mediated through neutrophil-dependent TLR5 signaling.

  1. Kingella kingae expresses type IV pili that mediate adherence to respiratory epithelial and synovial cells.

    Science.gov (United States)

    Kehl-Fie, Thomas E; Miller, Sara E; St Geme, Joseph W

    2008-11-01

    Kingella kingae is a gram-negative bacterium that colonizes the respiratory tract and is a common cause of septic arthritis and osteomyelitis. Despite the increasing frequency of K. kingae disease, little is known about the mechanism by which this organism adheres to respiratory epithelium and seeds joints and bones. Previous work showed that K. kingae expresses long surface fibers that vary in surface density. In the current study, we found that these fibers are type IV pili and are necessary for efficient adherence to respiratory epithelial and synovial cells and that the number of pili expressed by the bacterium correlates with the level of adherence to synovial cells but not with the level of adherence to respiratory cells. In addition, we established that the major pilin subunit is encoded by a pilA homolog in a conserved region of the chromosome that also contains a second pilin gene and a type IV pilus accessory gene, both of which are dispensable for pilus assembly and pilus-mediated adherence. Upon examination of the K. kingae genome, we identified two genes in physically separate locations on the chromosome that encode homologs of the Neisseria PilC proteins and that have only a low level homology to each other. Examination of mutant strains revealed that both of the K. kingae PilC homologs are essential for a wild-type level of adherence to both respiratory epithelial and synovial cells. Taken together, these results demonstrate that type IV pili and the two PilC homologs play important roles in mediating K. kingae adherence.

  2. Kingella kingae Expresses Type IV Pili That Mediate Adherence to Respiratory Epithelial and Synovial Cells▿

    Science.gov (United States)

    Kehl-Fie, Thomas E.; Miller, Sara E.; St. Geme, Joseph W.

    2008-01-01

    Kingella kingae is a gram-negative bacterium that colonizes the respiratory tract and is a common cause of septic arthritis and osteomyelitis. Despite the increasing frequency of K. kingae disease, little is known about the mechanism by which this organism adheres to respiratory epithelium and seeds joints and bones. Previous work showed that K. kingae expresses long surface fibers that vary in surface density. In the current study, we found that these fibers are type IV pili and are necessary for efficient adherence to respiratory epithelial and synovial cells and that the number of pili expressed by the bacterium correlates with the level of adherence to synovial cells but not with the level of adherence to respiratory cells. In addition, we established that the major pilin subunit is encoded by a pilA homolog in a conserved region of the chromosome that also contains a second pilin gene and a type IV pilus accessory gene, both of which are dispensable for pilus assembly and pilus-mediated adherence. Upon examination of the K. kingae genome, we identified two genes in physically separate locations on the chromosome that encode homologs of the Neisseria PilC proteins and that have only a low level homology to each other. Examination of mutant strains revealed that both of the K. kingae PilC homologs are essential for a wild-type level of adherence to both respiratory epithelial and synovial cells. Taken together, these results demonstrate that type IV pili and the two PilC homologs play important roles in mediating K. kingae adherence. PMID:18757541

  3. ExpR coordinates the expression of symbiotically important, bundle-forming Flp pili with quorum sensing in Sinorhizobium meliloti.

    Science.gov (United States)

    Zatakia, Hardik M; Nelson, Cassandra E; Syed, Umair J; Scharf, Birgit E

    2014-04-01

    Type IVb pili in enteropathogenic bacteria function as a host colonization factor by mediating tight adherence to host cells, but their role in bacterium-plant symbiosis is currently unknown. The genome of the symbiotic soil bacterium Sinorhizobium meliloti contains two clusters encoding proteins for type IVb pili of the Flp (fimbrial low-molecular-weight protein) subfamily. To establish the role of Flp pili in the symbiotic interaction of S. meliloti and its host, Medicago sativa, we deleted pilA1, which encodes the putative pilin subunit in the chromosomal flp-1 cluster and conducted competitive nodulation assays. The pilA1 deletion strain formed 27% fewer nodules than the wild type. Transmission electron microscopy revealed the presence of bundle-forming pili protruding from the polar and lateral region of S. meliloti wild-type cells. The putative pilus assembly ATPase CpaE1 fused to mCherry showed a predominantly unilateral localization. Transcriptional reporter gene assays demonstrated that expression of pilA1 peaks in early stationary phase and is repressed by the quorum-sensing regulator ExpR, which also controls production of exopolysaccharides and motility. Binding of acyl homoserine lactone-activated ExpR to the pilA1 promoter was confirmed with electrophoretic mobility shift assays. A 17-bp consensus sequence for ExpR binding was identified within the 28-bp protected region by DNase I footprinting analyses. Our results show that Flp pili are important for efficient symbiosis of S. meliloti with its plant host. The temporal inverse regulation of exopolysaccharides and pili by ExpR enables S. meliloti to achieve a coordinated expression of cellular processes during early stages of host interaction.

  4. Structural characterization of outer membrane components of the type IV pili system in pathogenic Neisseria.

    Directory of Open Access Journals (Sweden)

    Samta Jain

    Full Text Available Structures of the type IV pili secretin complexes from Neisseria gonorrhoeae and Neisseria meningitidis, embedded in outer membranes were investigated by transmission electron microscopy. Single particle averaging revealed additional domains not observed previously. Secretin complexes of N. gonorrhoeae showed a double ring structure with a 14-15-fold symmetry in the central ring, and a 14-fold symmetry of the peripheral ring with 7 spikes protruding. In secretin complexes of N. meningitidis, the spikes were absent and the peripheral ring was partly or completely lacking. When present, it had a 19-fold symmetry. The structures of the complexes in several pil mutants were determined. Structures obtained from the pilC1/C2 adhesin and the pilW minor pilin deletion strains were similar to wild-type, whereas deletion of the homologue of N. meningitidis PilW resulted in the absence of secretin structures. Remarkably, the pilE pilin subunit and pilP lipoprotein deletion mutants showed a change in the symmetry of the peripheral ring from 14 to 19 and loss of spikes. The pilF ATPase mutant also lost the spikes, but maintained 14-fold symmetry. These results show that secretin complexes contain previously unidentified large and flexible extra domains with a probable role in stabilization or assembly of type IV pili.

  5. Pili-like proteins of Akkermansia muciniphila modulate host immune responses and gut barrier function

    Science.gov (United States)

    Reunanen, Justus; Meijerink, Marjolein; Pietilä, Taija E.; Kainulainen, Veera; Klievink, Judith; Huuskonen, Laura; Aalvink, Steven; Skurnik, Mikael; Boeren, Sjef; Satokari, Reetta; Mercenier, Annick; Palva, Airi; Smidt, Hauke; de Vos, Willem M.; Belzer, Clara

    2017-01-01

    Gut barrier function is key in maintaining a balanced response between the host and its microbiome. The microbiota can modulate changes in gut barrier as well as metabolic and inflammatory responses. This highly complex system involves numerous microbiota-derived factors. The gut symbiont Akkermansia muciniphila is positively correlated with a lean phenotype, reduced body weight gain, amelioration of metabolic responses and restoration of gut barrier function by modulation of mucus layer thickness. However, the molecular mechanisms behind its metabolic and immunological regulatory properties are unexplored. Herein, we identify a highly abundant outer membrane pili-like protein of A. muciniphila MucT that is directly involved in immune regulation and enhancement of trans-epithelial resistance. The purified Amuc_1100 protein and enrichments containing all its associated proteins induced production of specific cytokines through activation of Toll-like receptor (TLR) 2 and TLR4. This mainly leads to high levels of IL-10 similar to those induced by the other beneficial immune suppressive microorganisms such as Faecalibacterium prausnitzii A2-165 and Lactobacillus plantarum WCFS1. Together these results indicate that outer membrane protein composition and particularly the newly identified highly abundant pili-like protein Amuc_1100 of A. muciniphila are involved in host immunological homeostasis at the gut mucosa, and improvement of gut barrier function. PMID:28249045

  6. A helynevek szerepe az alternatív ideologikus gondolkodásban I. A Pilis-kultusz esete [The role of place names in an alternative ideological mindset I. The case of the Pilis Cult

    Directory of Open Access Journals (Sweden)

    Imreh, Réka

    2014-12-01

    Full Text Available This paper focuses on the role of place names in defining and legitimizing the identity of a subculture through the example of a complex contemporary alternative social phenomenon known as the Pilis Cult. The Pilis Cult, which is also linked with some other alternative theories (Sumerian–Hungarian linguistic affinity, root linguistics, The Holy Crown Doctrine, claims that the Pilis Mountains as a spiritual space have a special role in Hungarian history. In the specific attitude to language and place names adopted by this subculture, one can recognize elements similar to those of ancient and medieval magical thinking. These can be observed in the interpretation of place names of the mountains, in which associations connected to the phonetic forms or the semantics of the place names may turn these toponyms into “telling names”, proving 120 Imreh Réka the antiquity and spirituality of the area. This etymological-associative narration is illustrated in the paper with the examples of the place names Pilis and Dobogó-kő. The interpretations of these names commingling with the alternative ideas connected to the denotata themselves (e.g. heart chakra theory; Proto-Buda Theories establish a unified argumentation framework. The paper argues that even a linguistically unorthodox subculture – alongside its specific ideology – may emphasize aspects of the study of place names through which our knowledge can be expanded with respect, for instance, to the functional logic behind place names.

  7. Pseudomonas aeruginosa bacteriophage PA1Ø requires type IV pili for infection and shows broad bactericidal and biofilm removal activities.

    Science.gov (United States)

    Kim, Shukho; Rahman, Marzia; Seol, Sung Yong; Yoon, Sang Sun; Kim, Jungmin

    2012-09-01

    We isolated a new lytic Pseudomonas aeruginosa phage that requires type IV pili for infection. PA1Ø has a broad bactericidal spectrum, covering Gram-positive and Gram-negative bacteria, and can eradicate biofilm cells. PA1Ø may be developed as a therapeutic agent for biofilm-related mixed infections with P. aeruginosa and Staphylococcus aureus.

  8. Functional Analysis of Lactobacillus rhamnosus GG Pili in Relation to Adhesion and Immunomodulatory Interactions with Intestinal Epithelial Cells

    NARCIS (Netherlands)

    Lebeer, S.; Claes, I.J.; Tytgat, H.L.P.; Verhoeven, T.L.A.; Marien, E.; Ossowski, von I.; Reunanen, J.; Palva, A.; Vos, de W.M.; Keersmaecker, de S.C.; Vanderleyden, J.

    2012-01-01

    Lactobacillus rhamnosus GG, a probiotic with good survival capacity in the human gut, has well-documented adhesion properties and health effects. Recently, spaCBA-encoded pili that bind to human intestinal mucus were identified on its cell surface. Here, we report on the phenotypic analysis of a

  9. Functional Analysis of Lactobacillus rhamnosus GG Pili in Relation to Adhesion and Immunomodulatory Interactions with Intestinal Epithelial Cells

    NARCIS (Netherlands)

    Lebeer, S.; Claes, I.J.; Tytgat, H.L.P.; Verhoeven, T.L.A.; Marien, E.; Ossowski, von I.; Reunanen, J.; Palva, A.; Vos, de W.M.; Keersmaecker, de S.C.; Vanderleyden, J.

    2012-01-01

    Lactobacillus rhamnosus GG, a probiotic with good survival capacity in the human gut, has well-documented adhesion properties and health effects. Recently, spaCBA-encoded pili that bind to human intestinal mucus were identified on its cell surface. Here, we report on the phenotypic analysis of a spa

  10. New type IV pili-related genes involved in early stages of Ralstonia solanacearum potato infection.

    Science.gov (United States)

    Siri, María Inés; Sanabria, Analía; Boucher, Christian; Pianzzola, María Julia

    2014-07-01

    This study provides insights into the pathogenesis of Ralstonia solanacearum, in particular with regards to strains belonging to phylotype IIB, sequevar 1 (IIB-1) and their interaction with potato, its natural host. We performed a comparative genomic analysis among IIB-1 R. solanacearum strains with different levels of virulence in order to identify candidate virulence genes. With this approach, we identified a 33.7-kb deletion in a strain showing reduced virulence on potato. This region contains a cluster of six genes putatively involved in type IV pili (Tfp) biogenesis. Functional analysis suggests that these proteins contribute to several Tfp-related functions such as twitching motility and biofilm formation. In addition, this genetic cluster was found to contribute to early bacterial wilt pathogenesis and colonization fitness of potato roots.

  11. Architects at the bacterial surface - sortases and the assembly of pili with isopeptide bonds.

    Science.gov (United States)

    Hendrickx, Antoni P A; Budzik, Jonathan M; Oh, So-Young; Schneewind, Olaf

    2011-03-01

    The cell wall envelope of Gram-positive bacteria can be thought of as a surface organelle for the assembly of macromolecular structures that enable the unique lifestyle of each microorganism. Sortases - enzymes that cleave the sorting signals of secreted proteins to form isopeptide (amide) bonds between the secreted proteins and peptidoglycan or polypeptides - function as the principal architects of the bacterial surface. Acting alone or with other sortase enzymes, sortase construction leads to the anchoring of surface proteins at specific sites in the envelope or to the assembly of pili, which are fibrous structures formed from many protein subunits. The catalysis of intermolecular isopeptide bonds between pilin subunits is intertwined with the assembly of intramolecular isopeptide bonds within pilin subunits. Together, these isopeptide bonds endow these sortase products with adhesive properties and resistance to host proteases.

  12. Going wireless: Fe(III) oxide reduction without pili by Geobacter sulfurreducens strain JS-1.

    Science.gov (United States)

    Smith, Jessica A; Tremblay, Pier-Luc; Shrestha, Pravin Malla; Snoeyenbos-West, Oona L; Franks, Ashley E; Nevin, Kelly P; Lovley, Derek R

    2014-07-01

    Previous studies have suggested that the conductive pili of Geobacter sulfurreducens are essential for extracellular electron transfer to Fe(III) oxides and for optimal long-range electron transport through current-producing biofilms. The KN400 strain of G. sulfurreducens reduces poorly crystalline Fe(III) oxide more rapidly than the more extensively studied DL-1 strain. Deletion of the gene encoding PilA, the structural pilin protein, in strain KN400 inhibited Fe(III) oxide reduction. However, low rates of Fe(III) reduction were detected after extended incubation (>30 days) in the presence of Fe(III) oxide. After seven consecutive transfers, the PilA-deficient strain adapted to reduce Fe(III) oxide as fast as the wild type. Microarray, whole-genome resequencing, proteomic, and gene deletion studies indicated that this adaptation was associated with the production of larger amounts of the c-type cytochrome PgcA, which was released into the culture medium. It is proposed that the extracellular cytochrome acts as an electron shuttle, promoting electron transfer from the outer cell surface to Fe(III) oxides. The adapted PilA-deficient strain competed well with the wild-type strain when both were grown together on Fe(III) oxide. However, when 50% of the culture medium was replaced with fresh medium every 3 days, the wild-type strain outcompeted the adapted strain. A possible explanation for this is that the necessity to produce additional PgcA, to replace the PgcA being continually removed, put the adapted strain at a competitive disadvantage, similar to the apparent selection against electron shuttle-producing Fe(III) reducers in many anaerobic soils and sediments. Despite increased extracellular cytochrome production, the adapted PilA-deficient strain produced low levels of current, consistent with the concept that long-range electron transport through G. sulfurreducens biofilms is more effective via pili.

  13. Comparative genomic analysis of Lactobacillus rhamnosus GG reveals pili containing a human- mucus binding protein.

    Science.gov (United States)

    Kankainen, Matti; Paulin, Lars; Tynkkynen, Soile; von Ossowski, Ingemar; Reunanen, Justus; Partanen, Pasi; Satokari, Reetta; Vesterlund, Satu; Hendrickx, Antoni P A; Lebeer, Sarah; De Keersmaecker, Sigrid C J; Vanderleyden, Jos; Hämäläinen, Tuula; Laukkanen, Suvi; Salovuori, Noora; Ritari, Jarmo; Alatalo, Edward; Korpela, Riitta; Mattila-Sandholm, Tiina; Lassig, Anna; Hatakka, Katja; Kinnunen, Katri T; Karjalainen, Heli; Saxelin, Maija; Laakso, Kati; Surakka, Anu; Palva, Airi; Salusjärvi, Tuomas; Auvinen, Petri; de Vos, Willem M

    2009-10-06

    To unravel the biological function of the widely used probiotic bacterium Lactobacillus rhamnosus GG, we compared its 3.0-Mbp genome sequence with the similarly sized genome of L. rhamnosus LC705, an adjunct starter culture exhibiting reduced binding to mucus. Both genomes demonstrated high sequence identity and synteny. However, for both strains, genomic islands, 5 in GG and 4 in LC705, punctuated the colinearity. A significant number of strain-specific genes were predicted in these islands (80 in GG and 72 in LC705). The GG-specific islands included genes coding for bacteriophage components, sugar metabolism and transport, and exopolysaccharide biosynthesis. One island only found in L. rhamnosus GG contained genes for 3 secreted LPXTG-like pilins (spaCBA) and a pilin-dedicated sortase. Using anti-SpaC antibodies, the physical presence of cell wall-bound pili was confirmed by immunoblotting. Immunogold electron microscopy showed that the SpaC pilin is located at the pilus tip but also sporadically throughout the structure. Moreover, the adherence of strain GG to human intestinal mucus was blocked by SpaC antiserum and abolished in a mutant carrying an inactivated spaC gene. Similarly, binding to mucus was demonstrated for the purified SpaC protein. We conclude that the presence of SpaC is essential for the mucus interaction of L. rhamnosus GG and likely explains its ability to persist in the human intestinal tract longer than LC705 during an intervention trial. The presence of mucus-binding pili on the surface of a nonpathogenic Gram-positive bacterial strain reveals a previously undescribed mechanism for the interaction of selected probiotic lactobacilli with host tissues.

  14. The protective efficacy of pili from different strains of Moraxella bovis within the same serogroup against infectious bovine keratoconjunctivitis.

    Science.gov (United States)

    Lepper, A W; Moore, L J; Atwell, J L; Tennent, J M

    1992-09-01

    Three groups of ten calves were each immunised with a total of 400 micrograms pili prepared from three separate strains of Moraxella bovis in Alhydrogel-oil adjuvant as two divided, equal doses 21 days apart. Groups 1 and 2 each received a monovalent vaccine made from strain 4L and S276R respectively, which belonged to pili serogroup A. Group 3 received vaccine made from pili of strain Maff1, belonging to serogroup F. A further group of ten calves served as non-vaccinated controls. Calves in groups 1 and 2 had developed serogroup A-specific antibody and those in group 3 developed serogroup F-specific antibody, and some evidence of cross-reacting antibody was also detected when measured by an agglutination test using formalin-killed piliated cells of serogroup A strain 4L. Although antibody titres measured against purified pili by ELISA were highest with homologous serogroup antigens, cross-reactive titres to shared epitopes of M. bovis pili were also detected by this method. Ocular challenge of the 40 calves with virulent M. bovis of serogroup A strain S276R was carried out 14 days after the second vaccine dose. All non-vaccinated calves developed infectious bovine keratoconjunctivitis (IBK). The percentage protection in groups 1 (strain 4L) and 2 (strain S276R) was 60% and 80% respectively (P less than 0.05), with mean lesion scores of 0.7 and 0.3 out of a possible 6.0. The percentage protection of calves in group 3 (strain Maff1) was only 30%, with a mean lesion score of 1.4 compared with 2.2 for non-vaccinated controls. The present findings, together with other evidence indicating that immunity to IBK is serogroup-specific, suggest that inclusion of pili from one representative strain from each of the seven Australian and British serogroups in a polyvalent, subunit vaccine should effectively protect the majority of cattle against IBK caused by most field strains of M. bovis encountered in Australia and the United Kingdom.

  15. Functional Analysis of Lactobacillus rhamnosus GG Pili in Relation to Adhesion and Immunomodulatory Interactions with Intestinal Epithelial Cells

    Science.gov (United States)

    Claes, Ingmar; Tytgat, Hanne L. P.; Verhoeven, Tine L. A.; Marien, Eyra; von Ossowski, Ingemar; Reunanen, Justus; Palva, Airi; de Vos, Willem M.; De Keersmaecker, Sigrid C. J.; Vanderleyden, Jos

    2012-01-01

    Lactobacillus rhamnosus GG, a probiotic with good survival capacity in the human gut, has well-documented adhesion properties and health effects. Recently, spaCBA-encoded pili that bind to human intestinal mucus were identified on its cell surface. Here, we report on the phenotypic analysis of a spaCBA pilus knockout mutant in comparison with the wild type and other adhesin mutants. The SpaCBA pilus of L. rhamnosus GG showed to be key for efficient adherence to the Caco-2 intestinal epithelial cell (IEC) line and biofilm formation. Moreover, the spaCBA mutant induces an elevated level of interleukin-8 (IL-8) mRNA in Caco-2 cells compared to the wild type, possibly involving an interaction of lipoteichoic acid with Toll-like receptor 2. In contrast, an L. rhamnosus GG mutant without exopolysaccharides but with an increased exposure of pili leads to the reduced expression of IL-8. Using Transwells to partition bacteria from Caco-2 cells, IL-8 induction is blocked completely regardless of whether wild-type or mutant L. rhamnosus GG cells are used. Taken together, our data suggest that L. rhamnosus GG SpaCBA pili, while promoting strong adhesive interactions with IECs, have a functional role in balancing IL-8 mRNA expression induced by surface molecules such as lipoteichoic acid. PMID:22020518

  16. Functional analysis of Lactobacillus rhamnosus GG pili in relation to adhesion and immunomodulatory interactions with intestinal epithelial cells.

    Science.gov (United States)

    Lebeer, Sarah; Claes, Ingmar; Tytgat, Hanne L P; Verhoeven, Tine L A; Marien, Eyra; von Ossowski, Ingemar; Reunanen, Justus; Palva, Airi; Vos, Willem M de; Keersmaecker, Sigrid C J De; Vanderleyden, Jos

    2012-01-01

    Lactobacillus rhamnosus GG, a probiotic with good survival capacity in the human gut, has well-documented adhesion properties and health effects. Recently, spaCBA-encoded pili that bind to human intestinal mucus were identified on its cell surface. Here, we report on the phenotypic analysis of a spaCBA pilus knockout mutant in comparison with the wild type and other adhesin mutants. The SpaCBA pilus of L. rhamnosus GG showed to be key for efficient adherence to the Caco-2 intestinal epithelial cell (IEC) line and biofilm formation. Moreover, the spaCBA mutant induces an elevated level of interleukin-8 (IL-8) mRNA in Caco-2 cells compared to the wild type, possibly involving an interaction of lipoteichoic acid with Toll-like receptor 2. In contrast, an L. rhamnosus GG mutant without exopolysaccharides but with an increased exposure of pili leads to the reduced expression of IL-8. Using Transwells to partition bacteria from Caco-2 cells, IL-8 induction is blocked completely regardless of whether wild-type or mutant L. rhamnosus GG cells are used. Taken together, our data suggest that L. rhamnosus GG SpaCBA pili, while promoting strong adhesive interactions with IECs, have a functional role in balancing IL-8 mRNA expression induced by surface molecules such as lipoteichoic acid.

  17. Diarrhea-associated biofilm formed by enteroaggregative Escherichia coli and aggregative Citrobacter freundii: a consortium mediated by putative F pili

    Directory of Open Access Journals (Sweden)

    Araújo Ana CG

    2010-02-01

    Full Text Available Abstract Background Enteroaggregative Escherichia coli (EAEC are enteropathogenic strains identified by the aggregative adhesion (AA pattern that share the capability to form biofilms. Citrobacter freundii is classically considered as an indigenous intestinal species that is sporadically associated with diarrhea. Results During an epidemiologic study focusing on infantile diarrhea, aggregative C. freundii (EACF and EAEC strains were concomitantly recovered from a severe case of mucous diarrhea. Thereby, the occurrence of synergic events involving these strains was investigated. Coinfection of HeLa cells with EACF and EAEC strains showed an 8-fold increase in the overall bacterial adhesion compared with single infections (P traA were capable of forming bacterial aggregates only in the presence of EACF. Scanning electronic microscopy analyses revealed that bacterial aggregates as well as enhanced biofilms formed by EACF and traA-positive EAEC were mediated by non-bundle forming, flexible pili. Moreover, mixed biofilms formed by EACF and traA-positive EAEC strains were significantly reduced using nonlethal concentration of zinc, a specific inhibitor of F pili. In addition, EAEC strains isolated from diarrheic children frequently produced single biofilms sensitive to zinc. Conclusions Putative F pili expressed by EAEC strains boosted mixed biofilm formation when in the presence of aggregative C. freundii.

  18. Earthworm symbiont Verminephrobacter eiseniae mediates natural transformation within the host egg capsules using type IV pili

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    SEANA Kelyn DAVIDSON

    2014-10-01

    Full Text Available The dense microbial communities commonly associated with plants and animals should offer many opportunities for horizontal gene transfer (HGT through described mechanisms of DNA exchange including natural transformation. However, studies of the significance of natural transformation have focused primarily on pathogens. The study presented here demonstrates highly efficient DNA exchange by natural transformation in a common symbiont of earthworms. The obligate bacterial symbiont Verminephrobacter eiseniae is a member of a microbial consortium of the earthworm Eisenia fetida that is transmitted into the egg capsules to colonize the embryonic worms. In the study presented here, by testing for transformants under different conditions in culture, we demonstrate that V. eiseniae can incorporate free DNA from the environment, that competency is regulated by environmental factors, and that it is sequence specific. Mutations in the type IV pili of V. eiseniae resulted in loss of DNA uptake, implicating the type IV pilus (TFP apparatus in DNA uptake. Furthermore, injection of DNA carrying antibiotic-resistance genes into egg capsules resulted in transformants within the capsule, demonstrating the relevance of DNA uptake within the earthworm system. The ability to take up species-specific DNA from the environment may explain the maintenance of the relatively large, intact genome of this long-associated obligate symbiont, and provides a mechanism for acquisition of foreign genes within the earthworm system.

  19. Type IV pili of Acidithiobacillus ferrooxidans can transfer electrons from extracellular electron donors.

    Science.gov (United States)

    Li, Yongquan; Li, Hongyu

    2014-03-01

    Studies on Acidithiobacillus ferrooxidans accepting electrons from Fe(II) have previously focused on cytochrome c. However, we have discovered that, besides cytochrome c, type IV pili (Tfp) can transfer electrons. Here, we report conduction by Tfp of A. ferrooxidans analyzed with a conducting-probe atomic force microscope (AFM). The results indicate that the Tfp of A. ferrooxidans are highly conductive. The genome sequence of A. ferrooxidans ATCC 23270 contains two genes, pilV and pilW, which code for pilin domain proteins with the conserved amino acids characteristic of Tfp. Multiple alignment analysis of the PilV and PilW (pilin) proteins indicated that pilV is the adhesin gene while pilW codes for the major protein element of Tfp. The likely function of Tfp is to complete the circuit between the cell surface and Fe(II) oxides. These results indicate that Tfp of A. ferrooxidans might serve as biological nanowires transferring electrons from the surface of Fe(II) oxides to the cell surface. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Type-IV pili spectroscopic markers: applications in the quantification of piliation levels in Moraxella bovis cells by a FT-IR ANN-based model.

    Science.gov (United States)

    Bosch, Alejandra; Prieto, Claudia; Serra, Diego Omar; Martina, Pablo; Stämmbler, Maren; Naumann, Dieter; Schmitt, Jürgen; Yantorno, Osvaldo

    2010-08-01

    Type-IV pili are cell surface organelles found in a wide variety of Gram-negative bacteria. They have traditionally been detected by electron microscopy and ELISA techniques. However, these methodologies are not appropriate for the rapid discrimination and quantification of piliated and nonpiliated cells in industrial or field conditions. Here, the analysis of FT-IR spectra of piliated, nonpiliated and sheared Moraxella bovis cells, together with purified pili suspensions spectra, allowed the identification of 3 IR regions associated to spectroscopic markers of Type-IV pili: 1750-1600, 1450-1350 and 1280-950 cm(-1). Such IR-specific markers were found for piliated cells grown in different culture systems (liquid or solid media), independently of the strain or pili serotype. They were also sensitive to pili expression levels. Therefore, on the bases of these specific spectral features, an FT-IR ANN-based model was developed to classify piliation levels in 5 distinct groups. An overall classification rate of almost 90% demonstrates the strong potential of the ANN system developed to monitor M. bovis cultures in vaccine production.

  1. Book review, Ominis e bestias in su campidanu de iossu, Marcello Furio Pili

    Directory of Open Access Journals (Sweden)

    Manuel Graziani

    2011-12-01

    Full Text Available Ciò che ci ha più incuriosito di questa pubblicazione è il sottotitolo “Il rapporto tra uomini e animali nelle attività lavorative del passato e del presente”. L’autore Marcello Furio Pili, pur riconoscendo una sorta di omologazione della società umana a seguito della rivoluzione industriale, parte dal presupposto storico dell’unicità del rapporto con gli animali che da sempre è un tratto distintivo del popolo sardo. La ricerca si concentra su cinque paesi del Basso Campidano: Nuraminis, Monastir, Ussana, San Sperate e Sestu, ognuno trattato in una veste monografica a sé stante ma con la medesima struttura editoriale e contenutistica. Cinque paesi di stampo rurale la cui economia, almeno fino ai primi decenni del ’900, “era fondata essenzialmente sull’utilizzo della terra, agricoltura e allevamento di bestiame quindi, e quasi ogni altra attività ruotava intorno alla sfera del rus, della campagna”. Grande spazio viene dedicato, infatti, agli animali (bovini, equini, caprini, suidi, canidi, felini, leporidi, roditori, uccelli, insetti, ecc. che vengono classificati secondo la tassonomia risalente al Sistema della Natura di Linneo, con ovini e caprini accorpati in un unico paragrafo seguendo la moderna classificazione che li inserisce entrambi nella sottofamiglia Caprinae.Il grande formato del libro (21 × 29 cm e la presenza di numerose foto di animali, vegetazione e, soprattutto, vecchi strumenti di lavoro, rendono ancor più interessante questa ricerca che, pur essendo sostanzialmente di carattere antropologico, culturale e linguistico, è molto centrata sul rapporto uomo-animale: “Il rapporto con gli animali, in un modo o nell’altro, era, per quasi tutti i componenti della comunità, costante, necessario, inevitabile.”.

  2. Type IV pili in Francisella – A virulence trait in an intracellular pathogen

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    Emelie eNäslund Salomonsson

    2011-02-01

    Full Text Available Francisella tularensis is a highly virulent intracellular human pathogen that is capable of rapid proliferation in the infected host. Mutants affected in intracellular survival and growth are highly attenuated which highlights the importance of the intracellular phase of the infection. Genomic analysis has revealed that Francisella encodes all genes required for expression of functional type IV pili (Tfp, and in this focused review we summarise recent findings regarding this system in the pathogenesis of tularemia. Tfp are dynamic adhesive structures that have been identified as major virulence determinants in several human pathogens, but it is not obvious what role these structures could have in an intracellular pathogen like Francisella. In the human pathogenic strains, genes required for secretion and assembly of Tfp and one pilin, PilA, have shown to be required for full virulence. Importantly, specific genetic differences have been identified between the different Francisella subspecies where in the most pathogenic type A variants all genes are intact while several Tfp genes are pseudogenes in the less pathogenic type B strains. This suggests that there has been a selection for expression of Tfp with different properties in the different subspecies. There is also a possibility that the genetic differences reflect adaption to different environmental niches of the subspecies and plays a role in transmission of tularemia. This is also in line with recent findings where Tfp pilins are found to be glycosylated which could reflect a role for Tfp in the environment to promote survival and transmission. We are still far from understanding the role of Tfp in virulence and transmission of tularemia, but with the genomic information and genetic tools available we are in a good position to address these issues in the future.

  3. Pseudomonas aeruginosa Pore-Forming Exolysin and Type IV Pili Cooperate To Induce Host Cell Lysis

    Science.gov (United States)

    Basso, Pauline; Ragno, Michel; Elsen, Sylvie; Reboud, Emeline; Golovkine, Guillaume; Bouillot, Stephanie; Huber, Philippe; Lory, Stephen; Faudry, Eric

    2017-01-01

    ABSTRACT   Clinical strains of Pseudomonas aeruginosa lacking the type III secretion system genes employ a toxin, exolysin (ExlA), for host cell membrane disruption. Here, we demonstrated that ExlA export requires a predicted outer membrane protein, ExlB, showing that ExlA and ExlB define a new active two-partner secretion (TPS) system of P. aeruginosa. In addition to the TPS signals, ExlA harbors several distinct domains, which include one hemagglutinin domain, five arginine-glycine-aspartic acid (RGD) motifs, and a C-terminal region lacking any identifiable sequence motifs. However, this C-terminal region is important for the toxic activity, since its deletion abolishes host cell lysis. Using lipid vesicles and eukaryotic cells, including red blood cells, we demonstrated that ExlA has a pore-forming activity which precedes cell membrane disruption of nucleated cells. Finally, we developed a high-throughput cell-based live-dead assay and used it to screen a transposon mutant library of an ExlA-producing P. aeruginosa clinical strain for bacterial factors required for ExlA-mediated toxicity. The screen resulted in the identification of proteins involved in the formation of type IV pili as being required for ExlA to exert its cytotoxic activity by promoting close contact between bacteria and the host cell. These findings represent the first example of cooperation between a pore-forming toxin of the TPS family and surface appendages in host cell intoxication. PMID:28119472

  4. Cooperative retraction of bundled type IV pili enables nanonewton force generation.

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    Nicolas Biais

    2008-04-01

    Full Text Available The causative agent of gonorrhea, Neisseria gonorrhoeae, bears retractable filamentous appendages called type IV pili (Tfp. Tfp are used by many pathogenic and nonpathogenic bacteria to carry out a number of vital functions, including DNA uptake, twitching motility (crawling over surfaces, and attachment to host cells. In N. gonorrhoeae, Tfp binding to epithelial cells and the mechanical forces associated with this binding stimulate signaling cascades and gene expression that enhance infection. Retraction of a single Tfp filament generates forces of 50-100 piconewtons, but nothing is known, thus far, on the retraction force ability of multiple Tfp filaments, even though each bacterium expresses multiple Tfp and multiple bacteria interact during infection. We designed a micropillar assay system to measure Tfp retraction forces. This system consists of an array of force sensors made of elastic pillars that allow quantification of retraction forces from adherent N. gonorrhoeae bacteria. Electron microscopy and fluorescence microscopy were used in combination with this novel assay to assess the structures of Tfp. We show that Tfp can form bundles, which contain up to 8-10 Tfp filaments, that act as coordinated retractable units with forces up to 10 times greater than single filament retraction forces. Furthermore, single filament retraction forces are transient, whereas bundled filaments produce retraction forces that can be sustained. Alterations of noncovalent protein-protein interactions between Tfp can inhibit both bundle formation and high-amplitude retraction forces. Retraction forces build over time through the recruitment and bundling of multiple Tfp that pull cooperatively to generate forces in the nanonewton range. We propose that Tfp retraction can be synchronized through bundling, that Tfp bundle retraction can generate forces in the nanonewton range in vivo, and that such high forces could affect infection.

  5. Novel pili-like surface structures of Halobacterium salinarum strain R1 are crucial for surface adhesion

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    Gerald eLosensky

    2015-01-01

    Full Text Available It was recently shown that haloarchaeal strains of different genera are able to adhere to surfaces and form surface-attached biofilms. However the surface structures mediating the adhesion were still unknown. We have identified a novel surface structure with Halobacterium salinarum strain R1, crucial for surface adhesion. Electron microscopic studies of surface-attached cells frequently showed pili-like surface structures of two different diameters that were irregularly distributed on the surface. The thinner filaments, 7 - 8 nm in diameter, represented a so far unobserved novel pili-like structure. Examination of the Hbt. salinarum R1 genome identified two putative gene loci (pil-1 and pil-2 encoding type IV pilus biogenesis complexes besides the archaellum encoding fla gene locus. Both pil-1 and pil-2 were expressed as transcriptional units, and the transcriptional start of pil-1 was identified. In silico analyses revealed that the pil-1 locus is present with other euryarchaeal genomes whereas the pil-2 is restricted to haloarchaea. Comparative real time qRT-PCR studies indicated that the general transcriptional activity was reduced in adherent versus planktonic cells. In contrast, the transcription of pilB1 and pilB2, encoding putative type IV pilus assembly ATPases, was induced in comparison to the archaella assembly/motor ATPase (flaI and the ferredoxin gene. Mutant strains were constructed that incurred a flaI deletion or flaI/pilB1 gene deletions. The absence of flaI caused the loss of the archaella while the additional absence of pilB1 led to loss of the novel pili-like surface structures. The ΔflaI/ΔpilB1 double mutants showed a 10-fold reduction in surface adhesion compared to the parental strain. Since surface adhesion was not reduced with the non-archaellated ΔflaI mutants, the pil-1 filaments have a distinct function in the adhesion process.

  6. XML The Ability of Cellulose Polysaccharide and Curli Pili Production in Uropathogenic Escherichia Coli and its Association with Biofilm Formation Intensity

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    Zahra Khozein (MSc

    2016-01-01

    Full Text Available Background and Objective: the Formation of urinary infection by uropathogenic E.coli needs numerous virulence factors and biofilm formation is among these factors. Bacteria that form biofilms express phenotype traits that appear according to the bacteria type. Cellulose is an important compound on the outside of E.coli causing bacterial cell-cell reactions and connection to nonliving surfaces. Curli pili cause the reaction between cell-cell and surface-cell in biofilms and lead to bacteria aggregation. Microorganisms’ ability to form biofilm on a surface depends on the surface nature and its conditions. This study aimed at determining the production ability of cellulose polysaccharide and curli pili in UPEC strains, and its correlation with formation and intensity of biofilm. Methods: In this study carried out to compare the ability of cellulose and pili curli production ability in 40 uropathogenic E.coli isolates ,by morphotype method in Congo Red medium (CR, each isolate was incubated at 37 oC, for 24 hours. After 24 hours, all colonies’ morphology characteristics were studied Results: It was shown that 67.5% of strains produced cellulose and 72.5% produced curli pili. In addition, 92.6% and 89% of isolates that produce cellulose and curli, respectively, had a moderate to strong biofilm. Moreover, it was shown that there is a significant correlation between cellulose and / or curli pili production with biofilm intensity. Conclusion: About 70% of E.coli isolates from patients' urine are able to produce cellulose or curli pili; therefore, it can be concluded that the production of these two combinations is effective in amount and intensity of biofilm formation.

  7. Vaccination against infectious bovine keratoconjunctivitis: protective efficacy and antibody response induced by pili of homologous and heterologous strains of Moraxella bovis.

    Science.gov (United States)

    Lepper, A W

    1988-10-01

    The protective effect of 2 Moraxella bovis pili vaccines against infectious bovine keratoconjunctivitis (IBK) experimentally induced by homologous or heterologous strain challenge with virulent, haemolytic M. bovis strain, Dal 2d, was measured in trials using weaned calves aged 3 to 7 months. Purified pili vaccines were prepared from haemolytic strain Dal 2d, (pilus serogroup IV), and haemolytic strain Epp 63, (pilus serogroup III). Calves were challenged by conjunctival instillation of 1 x 10(9) colony forming units of virulent M. bovis strain Dal 2d 14 days after the second of 2 subcutaneous doses of vaccine. Each consisted of 200 micrograms of pili in alum-oil adjuvant administered at an interval of 21 days. In trial 1 the level of protection against challenge with the homologous strain was 46.7% (p less than 0.01). Small, rapidly resolving lesions of IBK occurred in some vaccinates compared with a larger proportion of severe lesions that required treatment in non-vaccinated calves (p less than 0.025). In trial 2, the level of protection against IBK after exposure of vaccinates to the homologous Dal 2d strain was 72.7%, but no significant level of protection or reduction in the size and duration of lesions was apparent in similarly challenged calves vaccinated with Epp 63 pili when contrasted with susceptible, non-vaccinated controls. No marked reduction in the duration of infection with M. bovis Dal 2d following challenge resulted from vaccination with pili of either of the serogroups III or IV. Rising homologous serum IgG antibody titres to serogroups III and IV pili were recorded in response to vaccination with each antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Binding of CFA/I Pili of Enterotoxigenic Escherichia coli to Asialo-GM1 Is Mediated by the Minor Pilin CfaE.

    Science.gov (United States)

    Madhavan, T P Vipin; Riches, James D; Scanlon, Martin J; Ulett, Glen C; Sakellaris, Harry

    2016-05-01

    CFA/I pili are representatives of a large family of related pili that mediate the adherence of enterotoxigenic Escherichia coli to intestinal epithelial cells. They are assembled via the alternate chaperone-usher pathway and consist of two subunits, CfaB, which makes up the pilus shaft and a single pilus tip-associated subunit, CfaE. The current model of pilus-mediated adherence proposes that CFA/I has two distinct binding activities; the CfaE subunit is responsible for binding to receptors of unknown structure on erythrocyte and intestinal epithelial cell surfaces, while CfaB binds to various glycosphingolipids, including asialo-GM1. In this report, we present two independent lines of evidence that, contrary to the existing model, CfaB does not bind to asialo-GM1 independently of CfaE. Neither purified CfaB subunits nor CfaB assembled into pili bind to asialo-GM1. Instead, we demonstrate that binding activity toward asialo-GM1 resides in CfaE and this is essential for pilus binding to Caco-2 intestinal epithelial cells. We conclude that the binding activities of CFA/I pili for asialo-GM1, erythrocytes, and intestinal cells are inseparable, require the same amino acid residues in CfaE, and therefore depend on the same or very similar binding mechanisms. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  9. 77 FR 77091 - Notice of February 22; May 17; August 23; and November 8, 2013, Meetings for Na Hoa Pili O Kaloko...

    Science.gov (United States)

    2012-12-31

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR National Park Service Notice of February 22; May 17; August 23; and November 8, 2013, Meetings for Na Hoa...; August 23; and November 8, 2013, meetings of the Na Hoa Pili O Kaloko- Honokohau National Historical...

  10. Lactobacillus rhamnosus GG Outcompetes Enterococcus faecium via Mucus-Binding Pili: Evidence for a Novel and Heterospecific Probiotic Mechanism.

    Science.gov (United States)

    Tytgat, Hanne L P; Douillard, François P; Reunanen, Justus; Rasinkangas, Pia; Hendrickx, Antoni P A; Laine, Pia K; Paulin, Lars; Satokari, Reetta; de Vos, Willem M

    2016-10-01

    Vancomycin-resistant enterococci (VRE) have become a major nosocomial threat. Enterococcus faecium is of special concern, as it can easily acquire new antibiotic resistances and is an excellent colonizer of the human intestinal tract. Several clinical studies have explored the potential use of beneficial bacteria to weed out opportunistic pathogens. Specifically, the widely studied Lactobacillus rhamnosus strain GG has been applied successfully in the context of VRE infections. Here, we provide new insight into the molecular mechanism underlying the effects of this model probiotic on VRE decolonization. Both clinical VRE isolates and L. rhamnosus GG express pili on their cell walls, which are the key modulators of their highly efficient colonization of the intestinal mucosa. We found that one of the VRE pilus clusters shares considerable sequence similarity with the SpaCBA-SrtC1 pilus cluster of L. rhamnosus GG. Remarkable immunological and functional similarities were discovered between the mucus-binding pili of L. rhamnosus GG and those of the clinical E. faecium strain E1165, which was characterized at the genome level. Moreover, E. faecium strain E1165 bound efficiently to mucus, which may be prevented by the presence of the mucus-binding SpaC protein or antibodies against L. rhamnosus GG or SpaC. These results present experimental support for a novel probiotic mechanism, in which the mucus-binding pili of L. rhamnosus GG prevent the binding of a potential pathogen to the host. Hence, we provide a molecular basis for the further exploitation of L. rhamnosus GG and its pilins for prophylaxis and treatment of VRE infections. Concern about vancomycin-resistant Enterococcus faecium causing nosocomial infections is rising globally. The arsenal of antibiotic strategies to treat these infections is nearly exhausted, and hence, new treatment strategies are urgently needed. Here, we provide molecular evidence to underpin reports of the successful clinical application of

  11. Sex Stereotype

    Institute of Scientific and Technical Information of China (English)

    倪媛

    2014-01-01

    This paper analyzes the social phenomenon—sex stereotype.The paper illustrates the characteristics of stereotype and discusses about the factors which influence sex stereotypes and the reasons of its existence.And it also found the positive role that sex stereotype plays in the communication.

  12. Phenotypical analysis of the Lactobacillus rhamnosus GG fimbrial spaFED operon: surface expression and functional characterization of recombinant SpaFED pili in Lactococcus lactis.

    Science.gov (United States)

    Rintahaka, Johanna; Yu, Xia; Kant, Ravi; Palva, Airi; von Ossowski, Ingemar

    2014-01-01

    A noticeable genomic feature of many piliated Gram-positive bacterial species is the presence of more than one pilus-encoding operon. Paradigmatically, the gut-adapted Lactobacillus rhamnosus GG strain contains two different fimbrial operons in its genome. However, whereas one of these operons (called spaCBA) is encoding for the functionally mucus-/collagen-binding SpaCBA pilus, for the other operon (called spaFED) any native expression of the SpaFED-called pili is still the subject of some uncertainty. Irrespective of such considerations, we decided it would be of relevance or interest to decipher the gross structure of this pilus type, and as well assess its functional capabilities for cellular adhesion and immunostimulation. For this, and by following the approach we had used previously to explicate the immuno-properties of SpaCBA pili, we constructed nisin-inducible expression clones producing either wild-type or SpaF pilin-deleted surface-assembled L. rhamnosus GG SpaFED pili on Lactococcus lactis cells. Using these piliated lactococcal constructs, we found that the pilin-polymerized architecture of a recombinant-produced SpaFED pilus coincides with sequence-based functional predictions of the related pilins, and in fact is prototypical of those other sortase-dependent pilus-like structures thus far characterized for piliated Gram-positive bacteria. Moreover, we confirmed that among the different pilin subunits encompassing spaFED operon-encoded pili, the SpaF pilin is a main adhesion determinant, and when present in the assembled structure can mediate pilus binding to mucus, certain extracellular matrix proteins, and different gut epithelial cell lines. However, somewhat unexpectedly, when recombinant SpaFED pili are surface-attached, we found that they could not potentiate the existing lactococcal cell-induced immune responses so elicited from intestinal- and immune-related cells, but rather instead, they could dampen them. Accordingly, we have now provided

  13. Phenotypical analysis of the Lactobacillus rhamnosus GG fimbrial spaFED operon: surface expression and functional characterization of recombinant SpaFED pili in Lactococcus lactis.

    Directory of Open Access Journals (Sweden)

    Johanna Rintahaka

    Full Text Available A noticeable genomic feature of many piliated Gram-positive bacterial species is the presence of more than one pilus-encoding operon. Paradigmatically, the gut-adapted Lactobacillus rhamnosus GG strain contains two different fimbrial operons in its genome. However, whereas one of these operons (called spaCBA is encoding for the functionally mucus-/collagen-binding SpaCBA pilus, for the other operon (called spaFED any native expression of the SpaFED-called pili is still the subject of some uncertainty. Irrespective of such considerations, we decided it would be of relevance or interest to decipher the gross structure of this pilus type, and as well assess its functional capabilities for cellular adhesion and immunostimulation. For this, and by following the approach we had used previously to explicate the immuno-properties of SpaCBA pili, we constructed nisin-inducible expression clones producing either wild-type or SpaF pilin-deleted surface-assembled L. rhamnosus GG SpaFED pili on Lactococcus lactis cells. Using these piliated lactococcal constructs, we found that the pilin-polymerized architecture of a recombinant-produced SpaFED pilus coincides with sequence-based functional predictions of the related pilins, and in fact is prototypical of those other sortase-dependent pilus-like structures thus far characterized for piliated Gram-positive bacteria. Moreover, we confirmed that among the different pilin subunits encompassing spaFED operon-encoded pili, the SpaF pilin is a main adhesion determinant, and when present in the assembled structure can mediate pilus binding to mucus, certain extracellular matrix proteins, and different gut epithelial cell lines. However, somewhat unexpectedly, when recombinant SpaFED pili are surface-attached, we found that they could not potentiate the existing lactococcal cell-induced immune responses so elicited from intestinal- and immune-related cells, but rather instead, they could dampen them. Accordingly, we

  14. Electronic properties of conductive pili of the metal-reducing bacterium Geobacter sulfurreducens probed by scanning tunneling microscopy

    Science.gov (United States)

    Veazey, Joshua P.; Reguera, Gemma; Tessmer, Stuart H.

    2011-12-01

    The metal-reducing bacterium Geobacter sulfurreducens produces conductive protein appendages known as “pilus nanowires” to transfer electrons to metal oxides and to other cells. These processes can be harnessed for the bioremediation of toxic metals and the generation of electricity in bioelectrochemical cells. Key to these applications is a detailed understanding of how these nanostructures conduct electrons. However, to the best of our knowledge, their mechanism of electron transport is not known. We used the capability of scanning tunneling microscopy (STM) to probe conductive materials with higher spatial resolution than other scanning probe methods to gain insights into the transversal electronic behavior of native, cell-anchored pili. Despite the presence of insulating cellular components, the STM topography resolved electronic molecular substructures with periodicities similar to those reported for the pilus shaft. STM spectroscopy revealed electronic states near the Fermi level, consistent with a conducting material, but did not reveal electronic states expected for cytochromes. Furthermore, the transversal conductance was asymmetric, as previously reported for assemblies of helical peptides. Our results thus indicate that the Geobacter pilus shaft has an intrinsic electronic structure that could play a role in charge transport.

  15. Creating Sex

    DEFF Research Database (Denmark)

    Cahana, Jonathan

    2016-01-01

    Thomas Laqueur’s influential yet controversial study Making Sex has, in many ways, revolutionized our understanding of sexuality in antiquity. Yet, most of Laqueur’s critics and supporters stressed the one-sex body, while the crux of his argument is the primacy of gender. Moreover, a systematic...

  16. Sex Offenders.

    Science.gov (United States)

    Hayes, Susan

    1991-01-01

    This paper on the problem of sex offending among individuals with intellectual disabilities examines the incidence of this problem, characteristics of intellectually disabled sex offenders, determination of whether the behavior is a paraphilia or functional age-related behavior, and treatment options, with emphasis on the situation in New South…

  17. Sex determination

    OpenAIRE

    McCullagh, W. McK. H.

    2013-01-01

    How the sex of offspring is determined has puzzled philosophers and scientists for millennia. Modern science has identified both genetic and environmental factors, but the question is still not yet fully answered.

  18. Why Sex?

    DEFF Research Database (Denmark)

    Nielsen, Rasmus

    2006-01-01

    It is assumed that most organisms have sex because the resulting genetic recombination allows Darwinian selection to work better. It is now shown that in water fleas, recombination does lead to fewer deleterious mutations.......It is assumed that most organisms have sex because the resulting genetic recombination allows Darwinian selection to work better. It is now shown that in water fleas, recombination does lead to fewer deleterious mutations....

  19. Hypervariable pili and flagella genes provide suitable new targets for DNA high-resolution melt-based genotyping of dairy Geobacillus spp.

    Science.gov (United States)

    Chauhan, Kanika; Seale, R Brent; Deeth, Hilton C; Turner, Mark S

    2014-10-01

    Although nonpathogenic in nature, spores of Geobacillus are able to attach to surfaces, germinate, and form biofilms, allowing rapid multiplication and persistence within milk powder processing plants, causing final product contamination, and eventually leading to a loss of revenue in terms of downgraded product quality. As a result, Geobacillus spp. have been found to be common contaminants of milk powder worldwide. Genotyping methods can help in gaining insight into the ecology and transmission of these thermophilic bacteria within and between dairy processing plants. The objective of this study was to use the assembled draft genomes of two Geobacillus spp. to identify and test new hypervariable genotyping targets for differentiating closely related dairy Geobacillus isolates. The two Geobacillus spp. strains obtained from high spore count powders were obtained in 2010 (isolate 7E) and in 1995 (isolate 126) and were previously shown to be of same genotype based on a variable number tandem repeat genotyping method. Significant nucleotide sequence variation was found in genes encoding pili and flagella, which were further investigated as suitable loci for a new high-resolution melt analysis (HRMA)-based genotyping method. Three genes encoding pulG (containing prepilin-type N-terminal cleavage domain), pilT (pili retraction protein), and fliW (flagellar assembly protein) were selected as targets for the new pili/flagella gene (PilFla) HRMA genotyping method. The three-gene-based PilFla-HRMA genotyping method differentiated 35 milk powder Geobacillus spp. isolates into 19 different genotype groups (D = 0.93), which compared favorably to the previous method (which used four variable number tandem repeat loci) that generated 16 different genotype groups (D = 0.90). In conclusion, through comparative genomics of two closely related dairy Geobacillus strains, we have identified new hypervariable regions that prove to be useful targets for highly discriminatory genotyping.

  20. Epidermal Cells Expressing Putative Cell Markers in Nonglabrous Skin Existing in Direct Proximity with the Distal End of the Arrector Pili Muscle

    Directory of Open Access Journals (Sweden)

    N. Torkamani

    2016-01-01

    Full Text Available Inconsistent with the view that epidermal stem cells reside randomly spread along the basal layer of the epidermal rete ridges, we found that epidermal cells expressing stem cell markers in nonglabrous skin exist in direct connection with the distal end of the arrector pili muscle. The epidermal cells that express stem cell markers consist of a subpopulation of basal keratinocytes located in a niche at the lowermost portion of the rete ridges at the distal arrector pili muscle attachment site. Keratinocytes in the epidermal stem cell niche express K15, MCSP, and α6 integrin. α5 integrin marks the distal end of the APM colocalized with basal keratinocytes expressing stem cell markers located in a well-protected and nourished environment at the lowermost point of the epidermis; these cells are hypothesized to participate directly in epidermal renewal and homeostasis and also indirectly in wound healing through communication with the hair follicle bulge epithelial stem cell population through the APM. Our findings, plus a reevaluation of the literature, support the hierarchical model of interfollicular epidermal stem cell units of Fitzpatrick. This new view provides insights into epidermal control and the possible involvement of epidermal stem cells in nonmelanoma skin carcinogenesis.

  1. [Lethal sex].

    Science.gov (United States)

    Rabinerson, David; Ben-Shitrit, Gadi; Glezerman, Marek

    2011-03-01

    Asphyxiophilic sex is a form of autoerotic activity, in which the user creates mechanical means (such as hanging or bondage) in order to achieve cerebral hypoxia, which, in turn, enhances sexual, as well as orgasmic, stimulus. Failure of safety mechanisms, created by the user, may lead to instant death as a result of asphyxiation or strangulation. This kind of sexual practice is more prevalent among men than in women. In cases of death, it is difficult to relate it to the sexual practice itself. Suicide and homicide are the main differential diagnoses. Closely related derivatives of asphyxiophilic sex are anesthesiophilia (inhalation of variable volatile substances) and electrophilia (use of electric current during sexual activity)--both also intended to enhance the sexual stimulation. These forms of sexual practice are less prevalent than asphyxiophilia.

  2. Sex during Pregnancy

    Science.gov (United States)

    ... Your 1- to 2-Year-Old Sex During Pregnancy KidsHealth > For Parents > Sex During Pregnancy A A ... safe sexual relationship during pregnancy. Is Sex During Pregnancy Safe? Sex is considered safe during all stages ...

  3. When Sex Is Painful

    Science.gov (United States)

    ... AQ FREQUENTLY ASKED QUESTIONS GYNECOLOGIC PROBLEMS FAQ020 When Sex Is Painful • How common is painful sex? • What causes pain during sex? • Where is pain during sex felt? • When should ...

  4. Sex during Pregnancy

    Science.gov (United States)

    ... Habits for TV, Video Games, and the Internet Sex During Pregnancy KidsHealth > For Parents > Sex During Pregnancy ... satisfying and safe sexual relationship during pregnancy. Is Sex During Pregnancy Safe? Sex is considered safe during ...

  5. When Sex Is Painful

    Science.gov (United States)

    ... AQ FREQUENTLY ASKED QUESTIONS GYNECOLOGIC PROBLEMS FAQ020 When Sex Is Painful • How common is painful sex? • What causes pain during sex? • Where is pain during sex felt? • When should ...

  6. Spectroscopic Studies of Abiotic and Biological Nanomaterials: Silver Nanoparticles, Rhodamine 6G Adsorbed on Graphene, and c-Type Cytochromes and Type IV Pili in Geobacter sulfurreducens

    Science.gov (United States)

    Thrall, Elizabeth S.

    This thesis describes spectroscopic studies of three different systems: silver nanoparticles, the dye molecule rhodamine 6G adsorbed on graphene, and the type IV pili and c-type cytochromes produced by the dissimilatory metal-reducing bacterium Geobacter sulfurreducens. Although these systems are quite different in some ways, they can all be considered examples of nanomaterials. A nanomaterial is generally defined as having at least one dimension below 100 nm in size. Silver nanoparticles, with sub-100 nm size in all dimensions, are examples of zero-dimensional nanomaterials. Graphene, a single atomic layer of carbon atoms, is the paradigmatic two-dimensional nanomaterial. And although bacterial cells are on the order of 1 μm in size, the type IV pili and multiheme c-type cytochromes produced by G. sulfurreducens can be considered to be one- and zero-dimensional nanomaterials respectively. A further connection between these systems is their strong interaction with visible light, allowing us to study them using similar spectroscopic tools. The first chapter of this thesis describes research on the plasmon-mediated photochemistry of silver nanoparticles. Silver nanoparticles support coherent electron oscillations, known as localized surface plasmons, at resonance frequencies that depend on the particle size and shape and the local dielectric environment. Nanoparticle absorption and scattering cross-sections are maximized at surface plasmon resonance frequencies, and the electromagnetic field is amplified near the particle surface. Plasmonic effects can enhance the photochemistry of silver particles alone or in conjunction with semiconductors according to several mechanisms. We study the photooxidation of citrate by silver nanoparticles in a photoelectrochemical cell, focusing on the wavelength-dependence of the reaction rate and the role of the semiconductor substrate. We find that the citrate photooxidation rate does not track the plasmon resonance of the silver

  7. Passive immunisation of neonatal lambs against infection with enteropathogenic Escherichia coli via colostrum of ewes immunised with crude and purified K99 pili.

    Science.gov (United States)

    Altmann, K; Mukkur, T K

    1983-09-01

    Lambs sucking ewes immunised four to five weeks before parturition with crude preparations of K99 and purified K99 pili of single subunit composition were protected against challenge infection with heterologous enteropathogenic Escherichia coli strains. In contrast, the majority of lambs sucking sham-immunised ewes suffered severe diarrhoea and dehydration, followed by death in nearly half of the affected lambs. Protection was related to the presence of antibody in the colostral whey and lamb sera. K99-specific antibody activity in the colostral whey was found to be confined to IgM and IgG (IgG1 and IgG2) but not to the IgA class.

  8. Učinak četiriju ljekovitih biljaka na proizvodnju, biokemijske pokazatelje u krvi i ilealnu mikrofloru u tovnih pilića.

    OpenAIRE

    Sharifi, Seyed D.; Khorsandi, Saeedeh H.; Khadem, Ali A.; Salehi, Abdolreza; Moslehi, Hamidreza

    2013-01-01

    Istraživanje je poduzeto s ciljem da se procijene učinci dodatka u hranu četiriju biljaka od medicinskog značenja na proizvodnju, sadržaj lipida u krvi i mikrofloru u ileumu. U pokus je bilo uzeto 336 jednodnevnih tovnih pilića linije Ross, nasumce raspoređenih, od kojih je svaki prošao šest tretmana s četiri ponavljanja. Hrana je bila jednake kalorične vrijednosti i dušičnog sastava, a sadržavala je 15 g/kg suhog kumina, 3 g/kg peperminta, 2 g/kg stolisnika i 2 g/kg biljke dubačac. Dva pripr...

  9. C-di-GMP Regulates Motile to Sessile Transition by Modulating MshA Pili Biogenesis and Near-Surface Motility Behavior in Vibrio cholerae.

    Science.gov (United States)

    Jones, Christopher J; Utada, Andrew; Davis, Kimberly R; Thongsomboon, Wiriya; Zamorano Sanchez, David; Banakar, Vinita; Cegelski, Lynette; Wong, Gerard C L; Yildiz, Fitnat H

    2015-10-01

    In many bacteria, including Vibrio cholerae, cyclic dimeric guanosine monophosphate (c-di-GMP) controls the motile to biofilm life style switch. Yet, little is known about how this occurs. In this study, we report that changes in c-di-GMP concentration impact the biosynthesis of the MshA pili, resulting in altered motility and biofilm phenotypes in V. cholerae. Previously, we reported that cdgJ encodes a c-di-GMP phosphodiesterase and a ΔcdgJ mutant has reduced motility and enhanced biofilm formation. Here we show that loss of the genes required for the mannose-sensitive hemagglutinin (MshA) pilus biogenesis restores motility in the ΔcdgJ mutant. Mutations of the predicted ATPase proteins mshE or pilT, responsible for polymerizing and depolymerizing MshA pili, impair near surface motility behavior and initial surface attachment dynamics. A ΔcdgJ mutant has enhanced surface attachment, while the ΔcdgJmshA mutant phenocopies the high motility and low attachment phenotypes observed in a ΔmshA strain. Elevated concentrations of c-di-GMP enhance surface MshA pilus production. MshE, but not PilT binds c-di-GMP directly, establishing a mechanism for c-di-GMP signaling input in MshA pilus production. Collectively, our results suggest that the dynamic nature of the MshA pilus established by the assembly and disassembly of pilin subunits is essential for transition from the motile to sessile lifestyle and that c-di-GMP affects MshA pilus assembly and function through direct interactions with the MshE ATPase.

  10. The protective efficacy of cloned Moraxella bovis pili in monovalent and multivalent vaccine formulations against experimentally induced infectious bovine keratoconjunctivitis (IBK).

    Science.gov (United States)

    Lepper, A W; Atwell, J L; Lehrbach, P R; Schwartzkoff, C L; Egerton, J R; Tennent, J M

    1995-07-01

    Calves were vaccinated with cloned Moraxella bovis pili of serogroup C (experiment 1) or B (experiment 2) either as a monovalent formulation or as part of a multivalent preparation with pili of six other serogroups. Within 4 weeks of the second vaccine dose vaccinated calves and non-vaccinated controls were challenged via the ocular route with either virulent M. bovis strain Dal2d (serogroup C) or M. bovis strain 3WO7 (serogroup B) in experiments 1 and 2, respectively. Calves vaccinated with multivalent vaccines had significantly lower antibody titres than those vaccinated with monovalent preparations. Nevertheless, the levels of protection against infectious bovine keratoconjunctivitis (IBK) achieved with multivalent vaccines were 72% and 83% for the groups challenged with M. bovis strains of serogroups B and C, respectively. The serogroup C monovalent vaccine gave 100% protection against experimentally induced IBK and M. bovis isolates cultured from the eyes 6 days post-challenge were identified as belonging solely to serogroup C. Unexpectedly, only 25% protection was achieved against homologous strain challenge of calves that received the monovalent serogroup B vaccine. Furthermore, the majority of M. bovis isolates recovered from calves in this group belonged to serogroup C, as did half of those isolates cultured from the multivalent vaccinates. The remaining bacterial isolates from the latter group, together with all isolates from the non-vaccinated controls, belonged to serogroup B. Results are consistent with the hypothesis that derivatives of the serogroup B challenge inoculum had expressed serogroup C pilus antigen within 6 days of the challenge, possibly as a result of pilus gene inversion occurring in response to the presence of specific antibody in eye tissues and tears.

  11. A novel putrescine importer required for type 1 pili-driven surface motility induced by extracellular putrescine in Escherichia coli K-12.

    Science.gov (United States)

    Kurihara, Shin; Suzuki, Hideyuki; Oshida, Mayu; Benno, Yoshimi

    2011-03-25

    Recently, many studies have reported that polyamines play a role in bacterial cell-to-cell signaling processes. The present study describes a novel putrescine importer required for induction of type 1 pili-driven surface motility. The surface motility of the Escherichia coli ΔspeAB ΔspeC ΔpotABCD strain, which cannot produce putrescine and cannot import spermidine from the medium, was induced by extracellular putrescine. Introduction of the gene deletions for known polyamine importers (ΔpotE, ΔpotFGHI, and ΔpuuP) or a putative polyamine importer (ΔydcSTUV) into the ΔspeAB ΔspeC ΔpotABCD strain did not affect putrescine-induced surface motility. The deletion of yeeF, an annotated putative putrescine importer, in the ΔspeAB ΔspeC ΔpotABCD ΔydcSTUV strain abolished surface motility in putrescine-supplemented medium. Complementation of yeeF by a plasmid vector restored surface motility. The surface motility observed in the present study was abolished by the deletion of fimA, suggesting that the surface motility is type 1 pili-driven. A transport assay using the yeeF(+) or ΔyeeF strains revealed that YeeF is a novel putrescine importer. The K(m) of YeeF (155 μM) is 40 to 300 times higher than that of other importers reported previously. On the other hand, the V(max) of YeeF (9.3 nmol/min/mg) is comparable to that of PotABCD, PotFGHI, and PuuP. The low affinity of YeeF for putrescine may allow E. coli to sense the cell density depending on the concentration of extracellular putrescine.

  12. Genomics of sex determination.

    Science.gov (United States)

    Zhang, Jisen; Boualem, Adnane; Bendahmane, Abdelhafid; Ming, Ray

    2014-04-01

    Sex determination is a major switch in the evolutionary history of angiosperm, resulting 11% monoecious and dioecious species. The genomic sequences of papaya sex chromosomes unveiled the molecular basis of recombination suppression in the sex determination region, and candidate genes for sex determination. Identification and analyses of sex determination genes in cucurbits and maize demonstrated conservation of sex determination mechanism in one lineage and divergence between the two systems. Epigenetic control and hormonal influence of sex determination were elucidated in both plants and animals. Intensive investigation of potential sex determination genes in model species will improve our understanding of sex determination gene network. Such network will in turn accelerate the identification of sex determination genes in dioecious species with sex chromosomes, which are burdensome due to no recombination in sex determining regions. The sex determination genes in dioecious species are crucial for understanding the origin of dioecy and sex chromosomes, particularly in their early stage of evolution.

  13. SEX EDUCATION

    Directory of Open Access Journals (Sweden)

    R N Srivastava

    1994-06-01

    Full Text Available Sex, though not everything in life, is a profoundly important aspect of human existence. It has evolved to serve more than reproductive functions; relational and recreational functions having taken precedence over procrea­tional. Sex has come to play a much wider socio-psychological function.Human sexuality is complex and multidimensional. It is subject to influence by multitude of factors often grouped as biological (e.g. genes, hormones, psychological (e.g. fear, anxiety, mood and socio-cultural (e.g. sex roles, values- religious/moral/ethical, customs. It is the interaction and interrelationship of these factors from the time of conception, through intrauterine life, infancy, childhood and adolescence, till adulthood (even later in life that determine the sexual development expressed as sexual attitudes and behaviour of the people. Learning, both social and cognitive, plays a significantly important role in such development.Sexual dysfunctions in men and women, result from factors often categorised as physical or organic and psychological; more often a combination may be involved. Experience has shown that in majority of men and women in India having sexual problems, ignorance misconceptions and prevailing myths are invariably responsible in the causation of Ihese problems. Sexual problems in individual man (e.g. erectile failure and woman (e.g. vaginismus cause anxiety, feelings of frustration, lowered self esteem and symptoms of depression. The condition may also affect the spouse; he/she, as a reaction to the problem in the partner, may develop sexual and psychosocial problems including distressed marital relationship. This may also have influence on general couple relationship, effecting adversely the quality of family life.Modern therapeutic endevours have made it possible now to offer effective therapy to most people who seek help for their sexual problems, thus preventing the consequences on couple relationship. However, there is also

  14. Sex Bias in Children.

    Science.gov (United States)

    Zalk, Sue Rosenberg; And Others

    This study investigated children's sex biased attitudes as a function of the sex, age, and race of the child as well as a geographical-SES factor. Two attitudes were measured on a 55-item questionnaire: Sex Pride (attributing positive characteristics to a child of the same sex) and Sex Prejudice (attributing negative characteristics to a child of…

  15. Sex-linked dominant

    Science.gov (United States)

    Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... can be either an autosomal chromosome or a sex chromosome. It also depends on whether the trait ...

  16. Sex and Arthritis

    Science.gov (United States)

    ... Well with Rheumatic Disease Sex & Arthritis Sex and Arthritis Fast Facts Sex and arthritis can coexist. Open ... ability for sexual expression and enjoyment. Impact of Arthritis on Sexual Expression Aspects of arthritis which can ...

  17. A scaffold protein connects type IV pili with the Chp chemosensory system to mediate activation of virulence signaling in Pseudomonas aeruginosa.

    Science.gov (United States)

    Inclan, Yuki F; Persat, Alexandre; Greninger, Alexander; Von Dollen, John; Johnson, Jeffery; Krogan, Nevan; Gitai, Zemer; Engel, Joanne N

    2016-08-01

    Type IV pili (TFP) function as mechanosensors to trigger acute virulence programs in Pseudomonas aeruginosa. On surface contact, TFP retraction activates the Chp chemosensory system phosphorelay to upregulate 3', 5'-cyclic monophosphate (cAMP) production and transcription of virulence-associated genes. To dissect the specific interactions mediating the mechanochemical relay, we used affinity purification/mass spectrometry, directed co-immunoprecipitations in P. aeruginosa, single cell analysis of contact-dependent transcriptional reporters, subcellular localization and bacterial two hybrid assays. We demonstrate that FimL, a Chp chemosensory system accessory protein of unknown function, directly links the integral component of the TFP structural complex FimV, a peptidoglycan binding protein, with one of the Chp system output response regulators PilG. FimL and PilG colocalize at cell poles in a FimV-dependent manner. While PilG phosphorylation is required for TFP function and mechanochemical signaling, it is not required for polar localization or binding to FimL. Phylogenetic analysis reveals other bacterial species simultaneously encode TFP, the Chp system, FimL, FimV and adenylate cyclase homologs, suggesting that surface sensing may be widespread among TFP-expressing bacteria. We propose that FimL acts as a scaffold enabling spatial colocalization of TFP and Chp system components to coordinate signaling leading to cAMP-dependent upregulation of virulence genes on surface contact. © 2016 John Wiley & Sons Ltd.

  18. H-NS Nucleoid Protein Controls Virulence Features of Klebsiella pneumoniae by Regulating the Expression of Type 3 Pili and the Capsule Polysaccharide

    Science.gov (United States)

    Ares, Miguel A.; Fernández-Vázquez, José L.; Rosales-Reyes, Roberto; Jarillo-Quijada, Ma. Dolores; von Bargen, Kristine; Torres, Javier; González-y-Merchand, Jorge A.; Alcántar-Curiel, María D.; De la Cruz, Miguel A.

    2016-01-01

    Klebsiella pneumoniae is an opportunistic pathogen causing nosocomial infections. Main virulence determinants of K. pneumoniae are pili, capsular polysaccharide, lipopolysaccharide, and siderophores. The histone-like nucleoid-structuring protein (H-NS) is a pleiotropic regulator found in several gram-negative pathogens. It has functions both as an architectural component of the nucleoid and as a global regulator of gene expression. We generated a Δhns mutant and evaluated the role of the H-NS nucleoid protein on the virulence features of K. pneumoniae. A Δhns mutant down-regulated the mrkA pilin gene and biofilm formation was affected. In contrast, capsule expression was derepressed in the absence of H-NS conferring a hypermucoviscous phenotype. Moreover, H-NS deficiency affected the K. pneumoniae adherence to epithelial cells such as A549 and HeLa cells. In infection experiments using RAW264.7 and THP-1 differentiated macrophages, the Δhns mutant was less phagocytized than the wild-type strain. This phenotype was likely due to the low adherence to these phagocytic cells. Taken together, our data indicate that H-NS nucleoid protein is a crucial regulator of both T3P and CPS of K. pneumoniae. PMID:26904512

  19. Insects and sex

    OpenAIRE

    Beukeboom, Leo

    2005-01-01

    Most organisms reproduce sexually, but the evolution of sexual reproduction is not yet well understood. Sexual reproduction leads to new variation and adaptations to the environment, but sex is also costly. Some insects reproduce without sex through parthenogenesis or paedogenesis. Almost all sexual insects have two separate sexes, male and female. There are many mechanisms of sex determination. Most insects have male heterogamety (males XY, females XX). Female heterogamety and haplodiploidy ...

  20. Sex Differences in Cognition

    Science.gov (United States)

    Fairweather, Hugh

    1976-01-01

    Sex differences in cognitive skills, grouped into motor, spatial and linguistic areas, are assessed in relation to current theories of cerebral lateralization. Few convincing sex differences exist, either overall, or in interactions with functional localization. Qualifying criteria include age, birth order, culture, sex of experimenter and sex…

  1. Sexing young snowy owls

    Science.gov (United States)

    Seidensticker, M.T.; Holt, D.W.; Detienne, J.; Talbot, S.; Gray, K.

    2011-01-01

    We predicted sex of 140 Snowy Owl (Bubo scandiacus) nestlings out of 34 nests at our Barrow, Alaska, study area to develop a technique for sexing these owls in the field. We primarily sexed young, flightless owls (3844 d old) by quantifying plumage markings on the remiges and tail, predicting sex, and collecting blood samples to test our field predictions using molecular sexing techniques. We categorized and quantified three different plumage markings: two types of bars (defined as markings that touch the rachis) and spots (defined as markings that do not touch the rachis). We predicted sex in the field assuming that males had more spots than bars and females more bars than spots on the remiges and rectrices. Molecular data indicated that we correctly sexed 100% of the nestlings. We modeled the data using random forests and classification trees. Both models indicated that the number and type of markings on the secondary feathers were the most important in classifying nestling sex. The statistical models verified our initial qualitative prediction that males have more spots than bars and females more bars than spots on flight feathers P6P10 for both wings and tail feathers T1 and T2. This study provides researchers with an easily replicable and highly accurate method for sexing young Snowy Owls in the field, which should aid further studies of sex-ratios and sex-related variation in behavior and growth of this circumpolar owl species. ?? 2011 The Raptor Research Foundation, Inc.

  2. A Sex Work Research Symposium: Examining Positionality in Documenting Sex Work and Sex Workers’ Rights

    Directory of Open Access Journals (Sweden)

    Megan Lowthers

    2017-04-01

    Full Text Available Historically, academic literature on sex work has documented the changing debates, policies, and cultural discourse surrounding the sex industry, and their impact on the rights of sex workers worldwide. As sex work scholars look to the future of sex workers’ rights, however, we are also in a critical moment of self-reflection on how sex work scholarship engages with sex worker communities, produces knowledge surrounding sex work, and represents the lived experiences of sex workers’ rights, organizing, and activism. In this short Communication, proceedings from a recent sex work research symposium entitled, Sexual Economies, Politics, and Positionality in Sex Work Research are presented. Held at the Centre for Refugee Studies at York University, this symposium is a response to the need for sex work researchers, sex workers, and sex worker-led organizations to come together and critically examine the future of research on sex work and the politics of documenting sex workers’ rights.

  3. Sex determination in amphibians.

    Science.gov (United States)

    Nakamura, Masahisa

    2009-05-01

    The heterogametic sex is male in all mammals, whereas it is female in almost all birds. By contrast, there are two heterogametic types (XX/XY and ZZ/ZW) for genetic sex determination in amphibians. Though the original heterogametic sex was female in amphibians, the two heterogametic types were probably interchangeable, suggesting that sex chromosomes evolved several times in this lineage. Indeed, the frog Rana rugosa has the XX/XY and ZZ/ZW sex-determining systems within a single species, depending on the local population in Japan. The XY and ZW geographic forms with differentiated sex chromosomes probably have a common origin as undifferentiated sex chromosomes resulted from the hybridization between the primary populations of West Japan and Kanto forms. It is clear that the sex chromosomes are still undergoing evolution in this species group. Regardless of the presence of a sex-determining gene in amphibians, the gonadal sex of some species can be changed by sex steroids. Namely, sex steroids can induce the sex reversal, with estrogens inducing the male-to-female sex reversal, whereas androgens have the opposite effect. In R. rugosa, gonadal activity of CYP19 (P450 aromatase) is correlated with the feminization of gonads. Of particular interest is that high levels of CYP19 expression are observed in indifferent gonads at time before sex determination. Increases in the expression of CYP19 in female gonads and CYP17 (P450 17alpha-hydroxylase/C17-20 lyase) in male gonads suggest that the former plays an important role in phenotypic female determination, whereas the latter is needed for male determination. Thus, steroids could be the key factor for sex determination in R. rugosa. In addition to the role of sex steroids in gonadal sex determination in this species, Foxl2 and Sox3 are capable of promoting CYP19 expression. Since both the genes are autosomal, another factor up-regulating CYP19 expression must be recruited. The factor, which may be located on the X or W

  4. Sex, epilepsy, and epigenetics.

    Science.gov (United States)

    Qureshi, Irfan A; Mehler, Mark F

    2014-12-01

    Epilepsy refers to a heterogeneous group of disorders that are associated with a wide range of pathogenic mechanisms, seizure manifestations, comorbidity profiles, and therapeutic responses. These characteristics are all influenced quite significantly by sex. As with other conditions exhibiting such patterns, sex differences in epilepsy are thought to arise-at the most fundamental level-from the "organizational" and "activational" effects of sex hormones as well as from the direct actions of the sex chromosomes. However, our understanding of the specific molecular, cellular, and network level processes responsible for mediating sex differences in epilepsy remains limited. Because increasing evidence suggests that epigenetic mechanisms are involved both in epilepsy and in brain sexual dimorphism, we make the case here that analyzing epigenetic regulation will provide novel insights into the basis for sex differences in epilepsy.

  5. Sex, epilepsy, and epigenetics

    OpenAIRE

    2014-01-01

    Epilepsy refers to a heterogeneous group of disorders that are associated with a wide range of pathogenic mechanisms, seizure manifestations, comorbidity profiles, and therapeutic responses. These characteristics are all influenced quite significantly by sex. As with other conditions exhibiting such patterns, sex differences in epilepsy are thought to arise—at the most fundamental level—from the “organizational” and “activational” effects of sex hormones as well as from the direct actions of ...

  6. Effect of age and sex on fiber and follicle characteristics of an Iranian native sheep

    Directory of Open Access Journals (Sweden)

    B Mobini

    2012-06-01

    Full Text Available The mammalian hair fibers represent an interesting biological material which also is used in the textile industry. Histological structures of the fibers and follicles differ not only among different species but also among different areas and ages in an animal species. Skin samples were collected from neonatal (1-2 months, young (3-9 months, young adult (1-2 years and old adult age groups (3 years and more. In each age group, six animals (3 each sex were utilized. Immediately after slaughtering the animals, tissues were collected from eight regions namely belly, neck, leg, rump, flank, forearm, shoulder and hip and were fixed in 10 percent neutral buffered formalin. Histologic sections were stained with hematoxylin-eosin and special stains. It was found that the general histological features of all Bakhtiari sheep fibers used in this study were similar to many other breeds sited in literature, however there were also some differences. All hairs of the various skin regions had a medulla. All the hair follicles were surrounded by associated structures such as the sweat and sebaceous glands and arrector pili muscles and located only in papillary layer of the dermis. The most common number of the secondary hair follicles in compound hair follicles was 4. The histology of all fibers and follicles in various skin regions showed no significant differences by sex in all the age groups studied. By age increase, all the fibers and their follicles were larger and well organized in all different skin regions.

  7. The evolution of sex ratios and sex-determining systems

    NARCIS (Netherlands)

    Uller, Tobias; Pen, Ido; Wapstra, Erik; Beukeboom, Leo W.; Komdeur, Jan

    Sex determination is a fundamental process governed by diverse mechanisms. Sex ratio selection is commonly implicated in the evolution of sex-determining systems, although formal models are rare. Here, we argue that, although sex ratio selection can induce shifts in sex determination, genomic

  8. The evolution of sex ratios and sex-determining systems

    NARCIS (Netherlands)

    Uller, Tobias; Pen, Ido; Wapstra, Erik; Beukeboom, Leo W.; Komdeur, Jan

    2007-01-01

    Sex determination is a fundamental process governed by diverse mechanisms. Sex ratio selection is commonly implicated in the evolution of sex-determining systems, although formal models are rare. Here, we argue that, although sex ratio selection can induce shifts in sex determination, genomic confli

  9. Plant Sex Determination.

    Science.gov (United States)

    Pannell, John R

    2017-03-06

    Sex determination is as important for the fitness of plants as it is for animals, but its mechanisms appear to vary much more among plants than among animals, and the expression of gender in plants differs in important respects from that in most animals. In this Minireview, I provide an overview of the broad variety of ways in which plants determine sex. I suggest that several important peculiarities of plant sex determination can be understood by recognising that: plants show an alternation of generations between sporophytic and gametophytic phases (either of which may take control of sex determination); plants are modular in structure and lack a germ line (allowing for a quantitative expression of gender that is not common in animals); and separate sexes in plants have ultimately evolved from hermaphroditic ancestors. Most theorising about sex determination in plants has focused on dioecious species, but we have much to learn from monecious or hermaphroditic species, where sex is determined at the level of modules, tissues or cells. Because of the fundamental modularity of plant development and potentially important evolutionary links between monoecy and dioecy, it may be useful to relax the distinction often made between 'developmental sex determination' (which underpins the development of male versus female flowers in monoecious species) and 'genetic sex determination' (which underpins the separation of males and females in dioecious species, often mediated by a genetic polymorphism and sex chromosomes). I also argue for relaxing the distinction between sex determination involving a genetic polymorphism and that involving responses to environmental or hormonal cues, because non-genetic cues might easily be converted into genetic switches.

  10. Sex tourism in Thailand.

    Science.gov (United States)

    Van Kerkwijk, C

    1992-01-01

    Many foreigners visit Thailand in search of sex. While long-distance tourism was long enjoyed by members of more privileged social classes, even the lower economical classes of Japan, Malaysia, Europe, America, and Australia can now afford to travel over long distances. This relatively new breed of tourist is more likely to be of lower socioeconomic and educational status and less likely to use condoms when having sex. An estimated 30,000 sex workers are active in Bangkok, of whom 7000/10,000 are females who work specifically in the tourism sector. 1/2-1/3 of the 600 commercial sex establishments in the city are visited by foreigners. Phuket, Pattaya, Koh Samui, and Chiangmai are also well-frequented by sex tourists. Overall, a large, diverse, inexpensive, and accessible commercial sex market exists in Thailand. One may meet sex workers quasi-ubiquitously and be assured to find someone capable of meeting one's sexual needs. With these attributes, Thailand strongly attracts tourists in search of sex. A certain degree of recklessness also prevails among those on vacation. Away from the peers and social mores of their native lands, tourists may engage in sexually activities without criticism. Likewise, Thai sex workers who cater to foreigners, especially females, enjoy more freedom and control in sexual relations than their peers who work among nationals. Neither single nor married women in Thailand are allowed much sexual freedom and are traditionally expected to be obliging docile, and submissive. The greater than normal personal latitude enjoyed by both sex worker and foreigner lead to more negotiation on condom use and overall lower use. As such, Thailand's commercial sex market with foreigners' involvement therein threatens to spread HIV to many other countries throughout the world.

  11. Single-Sex Classrooms

    Science.gov (United States)

    Protheroe, Nancy

    2009-01-01

    Although single-sex education was once the norm in the U.S., the practice has largely been confined to private schools for more than a century. However, with the introduction of the final version of the U.S. Department of Education's so-called single-sex regulations in 2006, public schools were allowed greater flexibility to offer single-sex…

  12. Sex Discrimination in Coaching.

    Science.gov (United States)

    Dessem, Lawrence

    1980-01-01

    Even in situations in which the underpayment of girls' coaches is due to the sex of the students coached rather than to the sex of the coaches, the coaches and the girls coached are victims of unlawful discrimination. Available from Harvard Women's Law Journal, Harvard Law School, Cambridge, MA 02138. (Author/IRT)

  13. Sex Away from Home

    Science.gov (United States)

    Greenwald, Harold

    1971-01-01

    The reasons why people who are normally truthful to their spouses engage in sex away from home are discussed. These reasons can include loneliness, ego building or the opportunity to have homosexual relations. Sex away from home is likely to increase since the number of people traveling is increasing. (Author/CG)

  14. Insects and sex

    NARCIS (Netherlands)

    Beukeboom, Leo

    2005-01-01

    Most organisms reproduce sexually, but the evolution of sexual reproduction is not yet well understood. Sexual reproduction leads to new variation and adaptations to the environment, but sex is also costly. Some insects reproduce without sex through parthenogenesis or paedogenesis. Almost all sexual

  15. Sex Determination, Sex Ratios, and Genetic Conflict

    NARCIS (Netherlands)

    Werren, John H.; Beukeboom, Leo W.

    1998-01-01

    Genetic mechanisms of sex determination are unexpectedly diverse and change rapidly during evolution. We review the role of genetic conflict as the driving force behind this diversity and turnover. Genetic conflict occurs when different components of a genetic system are subject to selection in

  16. Sex Determination, Sex Ratios, and Genetic Conflict

    NARCIS (Netherlands)

    Werren, John H.; Beukeboom, Leo W.

    1998-01-01

    Genetic mechanisms of sex determination are unexpectedly diverse and change rapidly during evolution. We review the role of genetic conflict as the driving force behind this diversity and turnover. Genetic conflict occurs when different components of a genetic system are subject to selection in oppo

  17. Enteropathogenic Escherichia coli (EPEC) adhesion to intestinal epithelial cells: role of bundle-forming pili (BFP), EspA filaments and intimin.

    Science.gov (United States)

    Cleary, Jennifer; Lai, Li-Ching; Shaw, Robert K; Straatman-Iwanowska, Anna; Donnenberg, Michael S; Frankel, Gad; Knutton, Stuart

    2004-03-01

    Enteropathogenic Escherichia coli (EPEC), an important paediatric diarrhoeal pathogen, employs multiple adhesins to colonize the small bowel and produces characteristic 'attaching and effacing' (A/E) lesions on small intestinal enterocytes. EPEC adhesins that have been associated with A/E adhesion and intestinal colonization include bundle-forming pili (BFP), EspA filaments and intimin. BFP are involved in bacteria-bacteria interaction and microcolony formation but their role in cell adhesion remains unclear; EspA filaments are components of the EPEC type III secretion system but since they interact directly with host cells they may also function as adhesins; intimin is the well characterized intimate EPEC adhesin which binds the translocated intimin receptor, Tir. However, other uncharacterized host cell receptors have been implicated in intimin-mediated adhesion. In this study, the role of BFP, EspA filaments and intimin in EPEC adhesion to intestinal brush border cells was assessed by observing adhesion of wild-type EPEC strain E2348/69 and a set of isogenic single, double and triple mutants in bfpA, espA and eae (intimin gene) to differentiated human intestinal Caco-2 cells. E2348/69 (bfpA(+) espA(+) eae(+)) adhered rapidly (border of Caco-2 cells and subsequently produced microcolonies and typical A/E lesions. Non-intimate brush border adhesion of double mutant strain UMD880 (bfpA(+) espA(-) eae(-)) also occurred rapidly, whereas adhesion of strain UMD886 (bfpA(-) espA(+) eae(-)) occurred later in the infection (>1 h) and with much lower efficiency; confocal microscopy indicated BFP and EspA-mediated adhesion, respectively. Strain UMD883 (bfpA(-) espA(-) eae(+)), which is unable to translocate Tir, was non-adherent although this strain was able to form intimate attachment and A/E lesions when co-cultured with strain CVD206 (bfpA(+) espA(+) eae(-)) which supplied Tir to the membrane. Single mutant strains CVD206 (bfpA(+) espA(+) eae(-)) and UMD872 (bfpA(+) esp

  18. Sex and Fertility After SCI

    Science.gov (United States)

    ... About Blog Facing Disability Jeff Shannon Donate Experts \\ Sex and Fertility After Spinal Cord Injury Topics Adult ... Spasticity, Physical Therapy-Lokomat Spasticity, Physical Therapy-Lokomat Sex and Fertility After Spinal Cord Injury Sex and ...

  19. [Negotiating safer sex].

    Science.gov (United States)

    Gordon, G; Charnock, D

    1991-01-01

    Women have generally assumed responsibility for contraception since the appearance of oral contraceptives and IUDs. But AIDS prevention programs are now asking women to assume responsibility for safer sex through use of condoms, a male method. Women are being asked to carry condoms, to negotiate their use each time they have sex, and to insist if the partner resists. The problem with this strategy is that frequently it is the male partner who makes sexual decisions, and women have less negotiating power. Women are considered feminine if they assume a passive role in sexual activity. This work suggests strategies to improve the negotiating power of women. Options and problems of speaking about safer sex vary in accordance with the nature of the relationship. A woman with a new partner can try to ascertain his sexual history, but may gain no information on his probable health even if he tells her the truth. It may be easier to convince him to use a condom at least in the beginning of the romance. Women working in the sex industry often have greater trouble convincing their friends and lovers to use a condom than their clients. Some family planning workers have begun to speak of safer sex with all their clients. Role playing and workshops or discussions with small groups of women having similar problems may help women overcome their reticence about discussing sexual topics. Some general suggestions to help women negotiate safer sex include choosing an opportune moment and planning in advance what to say; daring to speak directly without beating around the bush (the partner may also be gathering courage to speak); practicing placing condoms on objects and if necessary placing one on the partner without speaking; being honest with the partner about sex, love, and fidelity; and remembering that protection from condoms is mutual given that it is not possible to know who is infected. Until now, programs to help women practice safer sex have concentrated on sex industry

  20. Sex education in Portugal.

    Science.gov (United States)

    Frade, A; Vilar, D

    1991-05-01

    The article on sex education in Portugal covers background, the educational system, the clashes of the 1960's over sex education, the Committee for the Study of Sexuality and Education (CSSE), the policies, politics and social movements during the period 1974 - 1984, the discussions in Parliament, the 1988 Reform of the Educational System, the Family Planning Association (FPA) and sex education, and the future role of the FPA. It was not until the institution of the multiparity parliamentary system in 1974 that discussing social and political changes was possible, culminating in 1984 with new legislation on abortion, family planning, and sex education. School reform came in 1987/8 with the Ministry of Education primarily responsible for curricula. The 1960's brought with it the influence of the Catholic Church. Change came in the form of progressivism among Catholics who replaced dogma with dialogue and listening. Sex education was considered as preparation for marriage, but masturbation, contraception, and prostitution were also discussed. In addition, the founder of FPA chaired the CSSE in 1971 and opened up debate on sex issues and drafted a bill to establish co-education in Portuguese schools. The revolution of 1974 brought an end to censorship and brought forth a policy of developing family planning. Changed in the Family Code gave women greater equality. UNFPA supported teacher training in non-sexist education. With human reproduction included in the natural sciences, there was still no school sex education policy and contraception was only sometimes represented in the biology curriculum. The focus of FPA was on contraception and abortion. Finally in the 1980's, the first sex education programs were developed for out-of-school youth. Even though in the 1970's there were leftists groups promoting sex education, it took leftist parliamentary power to get legislation on sex education in the schools adopted. The Ministry of Education however was pressured by the

  1. A Sex Work Research Symposium: Examining Positionality in Documenting Sex Work and Sex Workers’ Rights

    National Research Council Canada - National Science Library

    Megan Lowthers; Magdalena Sabat; Elya M Durisin; Kamala Kempadoo

    2017-01-01

    Historically, academic literature on sex work has documented the changing debates, policies, and cultural discourse surrounding the sex industry, and their impact on the rights of sex workers worldwide...

  2. Etlik Piliçlerde Altlık Üzerine Dane Buğday Serpilmesinin Performans, Karkas Özellikleri, Dışkı pH ve Viskozitesi Üzerine Etkileri

    Directory of Open Access Journals (Sweden)

    Figen Kırkpınar

    2016-07-01

    Full Text Available Bu çalışmanın amacı, altık üzerine tüm dane buğday serpilmesinin etlik piliçlerde performans ve karkas özellikleri ile dışkı pH’sı ve viskozitesi üzerine etkilerini incelemektir. Toplam 336 adet günlük erkek civciv (Ross-308 rastgele her biri 4 tekerrürden oluşan 2 gruba ayrılmıştır. Her iki grupta da, 0-21. ve 22-45. günler arasında aynı başlatma ve bitirme yemleri kullanılmıştır. Deneme süresince tüm hayvanlara yem ve su ad-libitum olarak verilmiştir. Deneme gruplarından birine 8-21. günler arasında altık üzerine günde iki kez (saat 0800 ve 1200 rastgele tüm dane buğday (10 g/piliç/gün serpilmiştir. Altık üzerine tüm dane buğday serpilmesi erkek piliçlerin canlı ağırlığını 21. günde azaltırken 45. günde artırmıştır. Yem tüketimi tüm dane buğday uygulamasından etkilenmemiştir. Yemden yararlanma altlık üzerine tüm dane buğday serpilen grupta 21-45. ve 0-45. günler arasında kontrol grubuna göre önemli düzeyde iyileşmiştir. Ölüm oranı, karkas özellikleri ve dışkı viskozitesi bakımından gruplar arasında önemli düzeyde farklılıklar oluşmamıştır. Ancak, dışkı pH değeri altlık üzerine tüm dane buğday serpilen grupta kontrol grubuna kıyasla önemli düzeyde azalma göstermiştir. Bu sonuçlara göre, erken dönemde altık üzerine tüm dane buğday serpilmesi erkek etlik piliçlerin performansını olumlu etkilemiştir.

  3. Sex, Deportation and Rescue

    DEFF Research Database (Denmark)

    Plambech, Sine

    2017-01-01

    This contribution explores the economies interlinked by the migration of Nigerian women sex workers. The literature and politics of sex work migration and human trafficking economies are commonly relegated to the realm that focuses on profits for criminal networks and pimps, in particular...... recirculating the claim that human trafficking is the “third largest” criminal economy after drugs and weapons. Based on ethnographic fieldwork among Nigerian sex worker migrants conducted in Benin City, Nigeria, in 2011 and 2012, this study brings together four otherwise isolated migration economies...... – facilitation, remittances, deportation, and rescue – and suggests that we have to examine multiple sites and relink these in order to more fully understand the complexity of sex work migration. Drawing upon literature within transnational feminist analysis, critical human trafficking studies, and migration...

  4. Juvenile Sex Offenders.

    Science.gov (United States)

    Ryan, Eileen P; Otonichar, Joseph M

    2016-07-01

    Sexual offending by juveniles accounts for a sizable percentage of sexual offenses, especially against young children. In this article, recent research on female juvenile sex offenders (JSOs), risk factors for offending in juveniles, treatment, and the ways in which these youth may differ from general delinquents will be reviewed. Most JSOs do not go on to develop paraphilic disorders or to commit sex offenses during adulthood, and as a group, they are more similar to nonsexual offending juvenile delinquents than to adult sex offenders. Recent research has elucidated some differences between youth who commit sex offenses and general delinquents in the areas of atypical sexual interests, the use of pornography, and early sexual victimization during childhood.

  5. Somatic sex determination.

    Science.gov (United States)

    Zarkower, David

    2006-02-10

    C. elegans occurs in two natural sexes, the XX hermaphrodite and the XO male, which differ extensively in anatomy, physiology, and behavior. All somatic differences between the sexes result from the differential activity of a "global" sex determination regulatory pathway. This pathway also controls X chromosome dosage compensation, which is coordinated with sex determination by the action of the three SDC proteins. The SDC proteins control somatic and germline sex by transcriptional repression of the her-1 gene. HER-1 is a secreted protein that controls a regulatory module consisting of a transmembrane receptor, TRA-2, three intracellular FEM proteins, and the zinc finger transcription factor TRA-1. The molecular workings of this regulatory module are still being elucidated. Similarity of TRA-2 to patched receptors and of TRA-1 to GLI proteins suggests that parts of the global pathway originally derived from a Hedgehog signaling pathway. TRA-1 controls all aspects of somatic sexual differentiation, presumably by regulating a variety of tissue- and cell-specific downstream targets, including the cell death regulator EGL-1 and the male sexual regulator MAB-3. Sex determination evolves rapidly, and conservation of sexual regulators between phyla has been elusive. An apparent exception involves DM domain proteins, including MAB-3, which control sexual differentiation in nematodes, arthropods, and vertebrates. Important issues needing more study include the detailed molecular mechanisms of the global pathway, the identities of additional sexual regulators acting in the global pathway and downstream of TRA-1, and the evolutionary history of the sex determination pathway. Recently developed genetic and genomic technologies and comparative studies in divergent species have begun to address these issues.

  6. AIDS and sex tourism.

    Science.gov (United States)

    Herold, E S; Van Kerkwijk, C

    1992-01-01

    Tourists traveling internationally lower their inhibitions and take greater risks than they would typically in their home cultures. Loneliness, boredom, and a sense of freedom contribute to this behavioral change. Some tourists travel internationally in search of sexual gratification. This motivation may be actively conscious or subconscious to the traveler. Billed as romantic with great natural beauty, Thailand, the Philippines, Brazil, the Dominican Republic, and Kenya are popular destinations of tourists seeking sex. The Netherlands and countries in eastern Europe are also popular. With most initial cases of HIV infection in Europe having histories of international travel, mass tourism is a major factor in the international transmission of AIDS. While abroad, tourists have sex with casual partners, sex workers, and/or other tourists. Far from all tourists, however, carry and consistently use condoms with these partners. One study found female and non white travelers to be less likely than Whites and males to carry condoms. The risk of HIV infection increases in circumstances where condoms are not readily available in the host country and/or are of poor quality. Regarding actual condom use, a study found only 34% of sex tourists from Switzerland to consistently use condoms while abroad. 28% of men in an STD clinic in Melbourne, Australia, reported consistent condom use in sexual relations while traveling in Asia; STDs were identified in 73% of men examined. The few studies of tourists suggest that a significant proportion engage in risky behavior while traveling. HIV prevalence is rapidly increasing in countries known as destinations for sex tourism. High infection rates are especially evident among teenage sex workers in Thailand. Simply documenting the prevalence of risky behavior among sex tourists will not suffice. More research is needed on travelers and AIDS with particular attention upon the motivating factors supporting persistent high-risk behavior.

  7. Sex allocation and sex determination in squamate reptiles.

    Science.gov (United States)

    Wapstra, E; Warner, D A

    2010-01-01

    Reptiles possess a wide variety of sex determining mechanisms, more so than any other vertebrate group. They offer outstanding opportunities to understand the evolutionary transitions between modes of sex determination. In this review, we argue that sex allocation theory is fundamental for understanding the selective causes of such shifts. Whether selection for biased sex allocation actually results in evolutionary shifts in sex determination depends on the overall strength, direction and consistency of selection and to what extent existing reproductive systems can establish novel links between factors causing sex-specific fitness and mechanisms of sex determination. Perhaps one of the most exciting advances in recent years has been the phylogenetically diverse range in reptile taxa that form the basis of research on the evolution of sex determination. The traditional use of long-lived oviparous species (especially turtles and crocodiles) is now expanded to include a range of short-lived taxa that exhibit both genetic sex determination and environment-/temperature-dependent sex determination (particularly agamid lizards), as well as a greater emphasis on viviparous species. If selection on differential sex allocation is a key selective pressure for the evolution of sex-determining mechanisms, these taxa will provide considerable insights into the integrated fields of sex allocation biology and sex determination. (c) 2009 S. Karger AG, Basel.

  8. Sex Hormones and Tendon

    DEFF Research Database (Denmark)

    Hansen, Mette; Kjaer, Michael

    2016-01-01

    The risk of overuse and traumatic tendon and ligament injuries differ between women and men. Part of this gender difference in injury risk is probably explained by sex hormonal differences which are specifically distinct during the sexual maturation in the teenage years and during young adulthood....... The effects of the separate sex hormones are not fully elucidated. However, in women, the presence of estrogen in contrast to very low estrogen levels may be beneficial during regular loading of the tissue or during recovering after an injury, as estrogen can enhance tendon collagen synthesis rate. Yet...... has also been linked to a reduced responsiveness to relaxin. The present chapter will focus on sex difference in tendon injury risk, tendon morphology and tendon collagen turnover, but also on the specific effects of estrogen and androgens....

  9. Corruption and sex

    Directory of Open Access Journals (Sweden)

    Milutinović-Bojanić Sanja

    2013-01-01

    Full Text Available Taking into account the difference between the ancient and modern (even postmodern understandings of corruption, I am curious to explore why the bond linking corruption and sex seems so obvious. I have no intention of investigating both phenomena in the context of any moral category. What then did Flaubert have on his mind when he wrote that Rodolphe “treated Emma quite sans façon. He made of her something supple and corrupt.” What underpins the irresistible attraction between corruption and sex? Why is it impossible to eradicate corruption and repress sex and perceive them as solely functional strategies of generation and reproduction? This short outline follows certain philosophical remarks of Luce Irigaray and her thematization of the sexual difference in the demarcation of generation and corruption.

  10. Sex Trafficking of Minors.

    Science.gov (United States)

    Moore, Jessica L; Kaplan, Dana M; Barron, Christine E

    2017-04-01

    Sex trafficking is an increasingly recognized global health crisis affecting every country and region in the world. Domestic minor sex trafficking is a subset of commercial sexual exploitation of children, defined as engagement of minors (<18 years of age) in sexual acts for items of value (eg, food, shelter, drugs, money) involving children victimized within US borders. These involved youth are at risk for serious immediate and long-term physical and mental health consequences. Continued efforts are needed to improve preventive efforts, identification, screening, appropriate interventions, and subsequent resource provision for victimized and high-risk youth.

  11. Sex and deleterious mutations.

    Science.gov (United States)

    Gordo, Isabel; Campos, Paulo R A

    2008-05-01

    The evolutionary advantage of sexual reproduction has been considered as one of the most pressing questions in evolutionary biology. While a pluralistic view of the evolution of sex and recombination has been suggested by some, here we take a simpler view and try to quantify the conditions under which sex can evolve given a set of minimal assumptions. Since real populations are finite and also subject to recurrent deleterious mutations, this minimal model should apply generally to all populations. We show that the maximum advantage of recombination occurs for an intermediate value of the deleterious effect of mutations. Furthermore we show that the conditions under which the biggest advantage of sex is achieved are those that produce the fastest fitness decline in the corresponding asexual population and are therefore the conditions for which Muller's ratchet has the strongest effect. We also show that the selective advantage of a modifier of the recombination rate depends on its strength. The quantification of the range of selective effects that favors recombination then leads us to suggest that, if in stressful environments the effect of deleterious mutations is enhanced, a connection between sex and stress could be expected, as it is found in several species.

  12. Sex Education and Ideals

    Science.gov (United States)

    de Ruyter, Doret J.; Spiecker, Ben

    2008-01-01

    This article argues that sex education should include sexual ideals. Sexual ideals are divided into sexual ideals in the strict sense and sexual ideals in the broad sense. It is argued that ideals that refer to the context that is deemed to be most ideal for the gratification of sexual ideals in the strict sense are rightfully called sexual…

  13. Sex, Courtship, and Marriage.

    Science.gov (United States)

    Seiferth, Berniece

    The author presents an historical perspective on abortion, contraception and marriage as a prelude to an examination of changing attitudes toward sex. The article deals with the negative effects attributed to the increased incidence of early dating and early marriage of teenagers in the United States. The author also assumes positions on such…

  14. Sex Therapy and Mastectomy

    Science.gov (United States)

    Witkin, Mildred Hope

    1975-01-01

    Because the emotional trauma associated with a mastectomy exceeds the physical trauma, the recovery of the woman is greatly affected by the response of her husband or lover. Sex therapy, therefore, involves the couple. The approach described is aimed at assisting the couple to confront and integrate the mastectomy experience. (Author)

  15. When Sex Meets Law

    Institute of Scientific and Technical Information of China (English)

    YIN PUMIN

    2010-01-01

    @@ Ma Yaohai,an associate professor of computer science at Nanjing University of Technology in east China's Jiangsu Province,was sentenced to three and a half years in prison on May 20 for organizing group-sex parties,renewing nationwide debate on sexual freedom in China.

  16. Sex Therapy and Mastectomy

    Science.gov (United States)

    Witkin, Mildred Hope

    1975-01-01

    Because the emotional trauma associated with a mastectomy exceeds the physical trauma, the recovery of the woman is greatly affected by the response of her husband or lover. Sex therapy, therefore, involves the couple. The approach described is aimed at assisting the couple to confront and integrate the mastectomy experience. (Author)

  17. Sex education in Cyprus.

    Science.gov (United States)

    Patsalides, N

    1991-05-01

    The objective of educating people on family planning and sexuality issues has been carried forth by the Family Planning Association of Cyprus (FPAC) since 1971. The promotion of sex education in schools has generated respect for their expertise. Sex education has reached the agenda of the General Assembly of Parliament only to be postponed due to the April 1991 end of term dismissal. A newly elected Parliament are not expected to act immediately. The Ministry of Education Committee on Health Education has been actively counseled since 1974, and most recently in their examination of the possibilities of school sex education and training of high school teachers. The Ministry of Education has authority over primary and secondary education, which is compulsory up to 3 years of secondary education. The approach of FPAC has been to work with parents first in education lectures at various well publicized locations. The agenda was to inform about FPAC, explain the purpose and meaning of sex education, and show the Merry-Go-Round educational film followed by a question and answer session. Eventually, presentations involved children with parent observation. In 1977, authorization from the Ministry of Education gave official approval to FPAC, but not on school premises. FPAC went directly to headmasters and gained support in primary schools to organize sessions on school premises, which successfully involved many primary schools even in the much needed rural areas. Home Economics and Child Care, offered in the 5th and 6th grades was the only vehicle for gaining permission to enter secondary schools. In Larnaca, secondary school headmasters at the 3rd and 6th grade levels permitted invitations which requested parental permission. Lecture topics on human reproduction, sex roles, and disease and contraception were also provided in a follow-up letter. Higher education levels were involved through youth clubs and evening lectures. In 1988, FPAC urged the Director General of the

  18. Sex and life expectancy.

    Science.gov (United States)

    Seifarth, Joshua E; McGowan, Cheri L; Milne, Kevin J

    2012-12-01

    A sexual dimorphism in human life expectancy has existed in almost every country for as long as records have been kept. Although human life expectancy has increased each year, females still live longer, on average, than males. Undoubtedly, the reasons for the sex gap in life expectancy are multifaceted, and it has been discussed from both sociological and biological perspectives. However, even if biological factors make up only a small percentage of the determinants of the sex difference in this phenomenon, parity in average life expectancy should not be anticipated. The aim of this review is to highlight biological mechanisms that may underlie the sexual dimorphism in life expectancy. Using PubMed, ISI Web of Knowledge, and Google Scholar, as well as cited and citing reference histories of articles through August 2012, English-language articles were identified, read, and synthesized into categories that could account for biological sex differences in human life expectancy. The examination of biological mechanisms accounting for the female-based advantage in human life expectancy has been an active area of inquiry; however, it is still difficult to prove the relative importance of any 1 factor. Nonetheless, biological differences between the sexes do exist and include differences in genetic and physiological factors such as progressive skewing of X chromosome inactivation, telomere attrition, mitochondrial inheritance, hormonal and cellular responses to stress, immune function, and metabolic substrate handling among others. These factors may account for at least a part of the female advantage in human life expectancy. Despite noted gaps in sex equality, higher body fat percentages and lower physical activity levels globally at all ages, a sex-based gap in life expectancy exists in nearly every country for which data exist. There are several biological mechanisms that may contribute to explaining why females live longer than men on average, but the complexity of the

  19. Sex Education: Talking to Toddlers and Preschoolers about Sex

    Science.gov (United States)

    Healthy Lifestyle Sexual health Sex education often begins with a child's curiosity about his or her body. Here's how to set the stage for sex education — and how to answer your child's questions. ...

  20. [Sex chromosomes and meiosis].

    Science.gov (United States)

    Guichaoua, M-R; Geoffroy-Siraudin, C; Tassistro, V; Ghalamoun-Slaimi, R; Perrin, J; Metzler-Guillemain, C

    2009-01-01

    Sex chromosome behaviour fundamentally differs between male and female meiosis. In oocyte, X chromosomes synapse giving a XX bivalent which is not recognizable in their morphology and behaviour from autosomal bivalents. In human male, X and Y chromosomes differ from one another in their morphology and their genetic content, leading to a limited pairing and preventing genetic recombination, excepted in homologous region PAR1. During pachytene stage of the first meiotic prophase, X and Y chromosomes undergo a progressive condensation and form a transcriptionally silenced peripheral XY body. The condensation of the XY bivalent during pachytene stage led us to describe four pachytene substages and to localize the pachytene checkpoint between substages 2 and 3. We also defined the pachytene index (PI=P1+P2/P1+P2+P3+P4) which is always less than 0.50 in normal meiosis. XY body undergoes decondensation at diplotene stage, but transcriptional inactivation of the two sex chromosomes or Meiotic Sex Chromosome Inactivation (MSCI) persists through to the end of spermatogenesis. Sex chromosome inactivation involves several proteins, some of them were now identified. Two isoforms of the HP1 protein, HP1beta and HP1gamma, are involved in the facultative heterochromatinization of the XY body, but the initiation of this process involves the phosphorylation of the protein H2AX by the kinase ATR whose recruitment depends on BRCA1. Extensive researches on the inactivation of the sex chromosomes during male meiosis will allow to a better understanding of some male infertilities.

  1. Disestablishing Sex: The Case for Released-Time Sex Education

    Science.gov (United States)

    Glanzer, Perry L.

    2011-01-01

    Allowing nonschool organizations to provide sex education in a released-time format would disestablish state-funded sex education and give families a choice in the sex education that would be provided for their children. Released-time programs, as originally conceived and currently practiced, allow students to be released for a period of time…

  2. Disestablishing Sex: The Case for Released-Time Sex Education

    Science.gov (United States)

    Glanzer, Perry L.

    2011-01-01

    Allowing nonschool organizations to provide sex education in a released-time format would disestablish state-funded sex education and give families a choice in the sex education that would be provided for their children. Released-time programs, as originally conceived and currently practiced, allow students to be released for a period of time…

  3. Hypnotic Psychotherapy with Sex Offenders

    Science.gov (United States)

    Moseley, Sullivan; Briggs, Wanda P.; Magnus, Virginia

    2005-01-01

    The authors review the literature on the prevalence of sex offenders; multiple treatment modalities; and implications of the use of hypnotic psychotherapy, coupled with cognitive behavioral treatment programs, for treating sex offenders. (Contains 2 tables.)

  4. SHBG (Sex Hormone Binding Globulin)

    Science.gov (United States)

    ... as: Testosterone-estrogen Binding Globulin; TeBG Formal name: Sex Hormone Binding Globulin Related tests: Testosterone , Free Testosterone, ... I should know? How is it used? The sex hormone binding globulin (SHBG) test may be used ...

  5. Sex and Fertility After SCI

    Medline Plus

    Full Text Available ... having sex after a spinal cord injury? Can men and women still have sex after a spinal ... spinal cord injury? How is sexual function in men affected by a spinal cord injury ? What are ...

  6. The ABCs of Sex Ed.

    Science.gov (United States)

    Sroka, Stephen R.

    2002-01-01

    Cites statistics on extent of sexually transmitted diseases and pregnancies among adolescents; describes ideological dispute over how to teach sex education; advocates teaching the ABCs of sex education: Abstinence, Be Monogamous, and Condoms. (PKP)

  7. Sex Differences and Sex Steroids in Lung Health and Disease

    Science.gov (United States)

    Townsend, Elizabeth A.; Miller, Virginia M.

    2012-01-01

    Sex differences in the biology of different organ systems and the influence of sex hormones in modulating health and disease are increasingly relevant in clinical and research areas. Although work has focused on sex differences and sex hormones in cardiovascular, musculoskeletal, and neuronal systems, there is now increasing clinical evidence for sex differences in incidence, morbidity, and mortality of lung diseases including allergic diseases (such as asthma), chronic obstructive pulmonary disease, pulmonary fibrosis, lung cancer, as well as pulmonary hypertension. Whether such differences are inherent and/or whether sex steroids play a role in modulating these differences is currently under investigation. The purpose of this review is to define sex differences in lung structure/function under normal and specific disease states, with exploration of whether and how sex hormone signaling mechanisms may explain these clinical observations. Focusing on adult age groups, the review addresses the following: 1) inherent sex differences in lung anatomy and physiology; 2) the importance of certain time points in life such as puberty, pregnancy, menopause, and aging; 3) expression and signaling of sex steroid receptors under normal vs. disease states; 4) potential interplay between different sex steroids; 5) the question of whether sex steroids are beneficial or detrimental to the lung; and 6) the potential use of sex steroid signaling as biomarkers and therapeutic avenues in lung diseases. The importance of focusing on sex differences and sex steroids in the lung lies in the increasing incidence of lung diseases in women and the need to address lung diseases across the life span. PMID:22240244

  8. YY Sex: a Polar Candidate

    Science.gov (United States)

    Gabdeev, M. M.; Shimanskiy, V. V.; Borisov, N. V.; Tazieva, Z. R.

    2017-06-01

    We present spectroscopic investigations of a cataclysmic variable star, YY Sex. There are some uncertainties in the classification of this object. We calculate Doppler maps for Hβ and HeII λ4686Å and show that there is no sign of disk accretion in YY Sex. Consequently, we conclude that YY Sex is a polar.

  9. Sex Education: Challenges and Choices

    Science.gov (United States)

    MacKenzie, Alison; Hedge, Nicki; Enslin, Penny

    2017-01-01

    Noting public concern about sexual exploitation, abuse and sexualisation, we argue that sex education in the UK needs revision. Choice is a feature of current sex education policy and, acknowledging that choice can be problematic, we defend its place in an approach to sex education premised on informed deliberation, relational autonomy, a…

  10. Single Sex Education. WEEA Digest.

    Science.gov (United States)

    Pollard, Diane S.

    Title IX of the Educational Amendments of 1972 prohibits discrimination on the basis of sex in educational institutions that receive federal financial assistance. This digest focuses on the theme of single-sex education. Articles featured in this issue include: (1) "Single-Sex Education" (Diane S. Pollard); (2) "A Legal Framework for Single-Sex…

  11. Sex Stereotyping by Tomorrow's Executives.

    Science.gov (United States)

    Kovach, Kenneth A.

    1985-01-01

    Describes a study in which 512 college seniors were surveyed to see if members of one sex would implicitly stereotype by sex to a greater degree than the other. Questions concerned job/home conflicts and selection and promotion. Results indicated that men and women are equally guilty of sex stereotyping, which works against women in the workplace.…

  12. Same-sex parenting

    OpenAIRE

    Lokar, Daša

    2012-01-01

    Homosexuality has always caused a lot of fears, doubts, prejudice and stereotypes among people. Gay men and lesbians are being prosecuted, stigmatized, discriminated and put down just because of their sexual orientation. Nowadays we hear many discussions about the modern family relationships and partnerships, among which same-sex partnerships and families are also included. Public discussions are mainly concentrated on the question whether or not homosexual couples can be fit parents. Althoug...

  13. Wolbachia and Sex

    OpenAIRE

    Aper, Ian J.; Weglarz, Katie; Dohlen, Carol Von

    2016-01-01

    Insects with complex life cycles provide an ideal system for investigating the relationship between sex-skewing bacterial symbionts and the secondary loss of sexual reproduction. This research utilized the insect family Adelgidae, a group notorious for having peculiar and complex life cycles. In this family, some species have lost their sexual generation entirely, trapping them in asexual reproduction. Additionally, these insects are known to harbor multiple symbionts, both obligate and facul...

  14. The SW Sex enigma

    CERN Document Server

    Dhillon, V S; Marsh, T R

    2012-01-01

    The SW Sex stars are a class of cataclysmic variables, originally identified because they shared a number of enigmatic properties - most notably, single-peaked emission lines instead of the double-peaked lines one would expect from their high-inclination accretion discs. We present high time-resolution spectrophotometry of the eclipsing nova-like variables SW Sex and DW UMa, two of the founding members of the SW Sex class. Both systems show single-peaked Balmer and HeII 4686A emission lines that appear to originate from a region in the disc that lies close to, but downstream of, the bright spot. The emission-line light curves are consistent with the finding from X-ray and ultraviolet observations that we predominantly see the flared disc rim and the unobscured back portion of the disc in these systems. In DW UMa, the HeII 4686A emission line originates from close to the white dwarf and exhibits flaring. Such flares have been used to argue for magnetically-channelled accretion, as in the intermediate polars, b...

  15. Sex steroids and bone.

    Science.gov (United States)

    Manolagas, S C; Kousteni, S; Jilka, R L

    2002-01-01

    The adult skeleton is periodically remodeled by temporary anatomic structures that comprise juxtaposed osteoclast and osteoblast teams and replace old bone with new. Estrogens and androgens slow the rate of bone remodeling and protect against bone loss. Conversely, loss of estrogen leads to increased rate of remodeling and tilts the balance between bone resorption and formation in favor of the former. Studies from our group during the last 10 years have elucidated that estrogens and androgens decrease the number of remodeling cycles by attenuating the birth rate of osteoclasts and osteoblasts from their respective progenitors. These effects result, in part, from the transcriptional regulation of genes responsible for osteoclastogenesis and mesenchymal cell replication and/or differentiation and are exerted through interactions of the ligand-activated receptors with other transcription factors. However, increased remodeling alone cannot explain why loss of sex steroids tilts the balance of resorption and formation in favor of the former. Estrogens and androgens also exert effects on the lifespan of mature bone cells: pro-apoptotic effects on osteoclasts but anti-apoptotic effects on osteoblasts and osteocytes. These latter effects stem from a heretofore unexpected function of the classical "nuclear" sex steroid receptors outside the nucleus and result from activation of a Src/Shc/extracellular signal-regulated kinase signal transduction pathway probably within preassembled scaffolds called caveolae. Strikingly, estrogen receptor (ER) alpha or beta or the androgen receptor can transmit anti-apoptotic signals with similar efficiency, irrespective of whether the ligand is an estrogen or an androgen. More importantly, these nongenotropic, sex-nonspecific actions are mediated by the ligand-binding domain of the receptor and can be functionally dissociated from transcriptional activity with synthetic ligands. Taken together, these lines of evidence strongly suggest that

  16. Sex differences in brain epigenetics.

    Science.gov (United States)

    Menger, Yannick; Bettscheider, Marc; Murgatroyd, Chris; Spengler, Dietmar

    2010-12-01

    Sexual differentiation of the brain takes place during a perinatal-sensitive time window as a result of gonadal hormone-induced activational and organizational effects on neuronal substrates. Increasing evidence suggests that epigenetic mechanisms can contribute to the establishment and maintenance of some aspects of these processes, and that these epigenetic mechanisms may themselves be under the control of sex hormones. Epigenetic programming of neuroendocrine and behavioral phenotypes frequently occurs sex specifically, pointing to sex differences in brain epigenetics as a possible determinant. Understanding how sex-specific epigenomes and sex-biased responses to environmental cues contribute to the development of brain diseases might provide new insights for epigenetic therapy.

  17. Attitudes about Sex Selection and Sex Preference in Iranian Couples Referred for Sex Selection Technology

    Science.gov (United States)

    Ahmadi, Seyedeh Fatemeh; Shirzad, Mahdi; Kamali, Koorosh; Ranjbar, Fahimeh; Behjati-Ardakani, Zohreh; Akhondi, Mohammad Mehdi

    2015-01-01

    Background Gender preference is prevalent in some communities and using medical techniques to choose the baby's sex may cause the gender discrimination and gender imbalance in communities. Therefore, evaluating the gender preferences and attitudes towards using sex selection technologies seems to be necessary. Methods This cross-sectional study was conducted in Avicenna Fertility Center. Participants were 100 women with one child who were referred for sex selection. Data were collected through self-developed questionnaires. The questions were designed by the researchers at the experts’ panel. To determine the validity of the questionnaire, the viewpoints of professors specialized in these issues were obtained. The statistical analysis of the data was performed using SPSS software (Version 11.5), and p < 0.05 was considered significant. Results Tendency toward the male was more than female sex (55.5% male, 15.5% female and 28.5% no tendency). Majority of participants agreed with sex selection with medical reason and sex selection in order to balance the family. Women's level of education had positive effect on agreements to fetal sex selection with medical and non-medical reasons (p < 0.001). Conclusion Although gender preferences were toward the male sex but this preference was not very strong. Most participants agreed with non-medical sex selection for balancing the sex composition of their children. It doesn't seem that non-medical sex selection for family balancing causes severe sex imbalance in Iran. PMID:25717434

  18. Antibodies against the majority subunit of type IV Pili disperse nontypeable Haemophilus influenzae biofilms in a LuxS-dependent manner and confer therapeutic resolution of experimental otitis media.

    Science.gov (United States)

    Novotny, Laura A; Jurcisek, Joseph A; Ward, Michael O; Jordan, Zachary B; Goodman, Steven D; Bakaletz, Lauren O

    2015-04-01

    Despite resulting in a similar overall outcome, unlike antibodies directed against the DNABII protein, integration host factor (IHF), which induce catastrophic structural collapse of biofilms formed by nontypeable Haemophilus influenzae (NTHI), those directed against a recombinant soluble form of PilA [the majority subunit of Type IV pili (Tfp) produced by NTHI], mediated gradual 'top-down' dispersal of NTHI from biofilms. This dispersal occurred via a mechanism that was dependent upon expression of both PilA (and by inference, Tfp) and production of AI-2 quorum signaling molecules by LuxS. The addition of rsPilA to a biofilm-targeted therapeutic vaccine formulation comprised of IHF plus the powerful adjuvant dmLT and delivered via a noninvasive transcutaneous immunization route induced an immune response that targeted two important determinants essential for biofilm formation by NTHI. This resulted in significantly earlier eradication of NTHI from both planktonic and adherent populations in the middle ear, disruption of mucosal biofilms already resident within middle ears prior to immunization and rapid resolution of signs of disease in an animal model of experimental otitis media. These data support continued development of this novel combinatorial immunization approach for resolution and/or prevention of multiple diseases of the respiratory tract caused by NTHI.

  19. Type IV(B) pili are required for invasion but not for adhesion of Salmonella enterica serovar Typhi into BHK epithelial cells in a cystic fibrosis transmembrane conductance regulator-independent manner.

    Science.gov (United States)

    Bravo, Denisse; Blondel, Carlos J; Hoare, Anilei; Leyton, Lisette; Valvano, Miguel A; Contreras, Inés

    2011-11-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) has been proposed as an epithelial cell receptor for the entry of Salmonella Typhi but not Salmonella Typhimurium. The bacterial ligand recognized by CFTR is thought to reside either in the S. Typhi lipopolysaccharide core region or in the type IV pili. Here, we assessed the ability of virulent strains of S. Typhi and S. Typhimurium to adhere to and invade BHK epithelial cells expressing either the wild-type CFTR protein or the ∆F508 CFTR mutant. Both S. Typhi and S. Typhimurium invaded the epithelial cells in a CFTR-independent fashion. Furthermore and also in a CFTR-independent manner, a S. Typhi pilS mutant adhered normally to BHK cells but displayed a 50% reduction in invasion as compared to wild-type bacteria. Immunofluorescence microscopy revealed that bacteria and CFTR do not colocalize at the epithelial cell surface. Together, our results strongly argue against the established dogma that CFTR is a receptor for entry of Salmonella to epithelial cells.

  20. Talking to Your Kids about Sex

    Science.gov (United States)

    ... editorial staff Categories: Kids and Teens, Sex and Birth Control, Sex and SexualityTags: Adolescent Kids and Teens, Sex and Birth Control, Sex and Sexuality January 2017 Copyright © American Academy ...

  1. The many costs of sex.

    Science.gov (United States)

    Lehtonen, Jussi; Jennions, Michael D; Kokko, Hanna

    2012-03-01

    Explaining the evolution of sex is challenging for biologists. A 'twofold cost' compared with asexual reproduction is often quoted. If a cost of this magnitude exists, the benefits of sex must be large for it to have evolved and be maintained. Focusing on benefits can be misleading, as this sidelines important questions about the cost of sex: what is the source of the twofold cost: males, genome dilution or both? Does the cost deviate from twofold? What other factors make sex costly? How should the costs of sex be empirically measured? The total cost of sex and how it varies in different contexts must be known to determine the benefits needed to account for the origin and maintenance of sex. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Sex Determination, Sex Chromosomes, and Karyotype Evolution in Insects.

    Science.gov (United States)

    Blackmon, Heath; Ross, Laura; Bachtrog, Doris

    2017-01-01

    Insects harbor a tremendous diversity of sex determining mechanisms both within and between groups. For example, in some orders such as Hymenoptera, all members are haplodiploid, whereas Diptera contain species with homomorphic as well as male and female heterogametic sex chromosome systems or paternal genome elimination. We have established a large database on karyotypes and sex chromosomes in insects, containing information on over 13000 species covering 29 orders of insects. This database constitutes a unique starting point to report phylogenetic patterns on the distribution of sex determination mechanisms, sex chromosomes, and karyotypes among insects and allows us to test general theories on the evolutionary dynamics of karyotypes, sex chromosomes, and sex determination systems in a comparative framework. Phylogenetic analysis reveals that male heterogamety is the ancestral mode of sex determination in insects, and transitions to female heterogamety are extremely rare. Many insect orders harbor species with complex sex chromosomes, and gains and losses of the sex-limited chromosome are frequent in some groups. Haplodiploidy originated several times within insects, and parthenogenesis is rare but evolves frequently. Providing a single source to electronically access data previously distributed among more than 500 articles and books will not only accelerate analyses of the assembled data, but also provide a unique resource to guide research on which taxa are likely to be informative to address specific questions, for example, for genome sequencing projects or large-scale comparative studies.

  3. "Sex Hormones" in Secondary School Biology Textbooks

    Science.gov (United States)

    Nehm, Ross H.; Young, Rebecca

    2008-01-01

    This study explores the extent to which the term "sex hormone" is used in science textbooks, and whether the use of the term "sex hormone" is associated with pre-empirical concepts of sex dualism, in particular the misconceptions that these so-called "sex hormones" are sex specific and restricted to sex-related physiological functioning. We found…

  4. Environmental sex reversal, Trojan sex genes, and sex ratio adjustment: conditions and population consequences.

    Science.gov (United States)

    Stelkens, Rike B; Wedekind, Claus

    2010-02-01

    The great diversity of sex determination mechanisms in animals and plants ranges from genetic sex determination (GSD, e.g. mammals, birds, and most dioecious plants) to environmental sex determination (ESD, e.g. many reptiles) and includes a mixture of both, for example when an individual's genetically determined sex is environmentally reversed during ontogeny (ESR, environmental sex reversal, e.g. many fish and amphibia). ESD and ESR can lead to widely varying and unstable population sex ratios. Populations exposed to conditions such as endocrine-active substances or temperature shifts may decline over time due to skewed sex ratios, a scenario that may become increasingly relevant with greater anthropogenic interference on watercourses. Continuous exposure of populations to factors causing ESR could lead to the extinction of genetic sex factors and may render a population dependent on the environmental factors that induce the sex change. However, ESR also presents opportunities for population management, especially if the Y or W chromosome is not, or not severely, degenerated. This seems to be the case in many amphibians and fish. Population growth or decline in such species can potentially be controlled through the introduction of so-called Trojan sex genes carriers, individuals that possess sex chromosomes or genes opposite from what their phenotype predicts. Here, we review the conditions for ESR, its prevalence in natural populations, the resulting physiological and reproductive consequences, and how these may become instrumental for population management.

  5. Random sex determination: When developmental noise tips the sex balance.

    Science.gov (United States)

    Perrin, Nicolas

    2016-12-01

    Sex-determining factors are usually assumed to be either genetic or environmental. The present paper aims at drawing attention to the potential contribution of developmental noise, an important but often-neglected component of phenotypic variance. Mutual inhibitions between male and female pathways make sex a bistable equilibrium, such that random fluctuations in the expression of genes at the top of the cascade are sufficient to drive individual development toward one or the other stable state. Evolutionary modeling shows that stochastic sex determinants should resist elimination by genetic or environmental sex determinants under ecologically meaningful settings. On the empirical side, many sex-determination systems traditionally considered as environmental or polygenic actually provide evidence for large components of stochasticity. In reviewing the field, I argue that sex-determination systems should be considered within a three-ends continuum, rather than the classical two-ends continuum.

  6. Sex Ratio Elasticity Influences the Selection of Sex Ratio Strategy

    Science.gov (United States)

    Wang, Yaqiang; Wang, Ruiwu; Li, Yaotang; (Sam) Ma, Zhanshan

    2016-01-01

    There are three sex ratio strategies (SRS) in nature—male-biased sex ratio, female-biased sex ratio and, equal sex ratio. It was R. A. Fisher who first explained why most species in nature display a sex ratio of ½. Consequent SRS theories such as Hamilton’s local mate competition (LMC) and Clark’s local resource competition (LRC) separately explained the observed deviations from the seemingly universal 1:1 ratio. However, to the best of our knowledge, there is not yet a unified theory that accounts for the mechanisms of the three SRS. Here, we introduce the price elasticity theory in economics to define sex ratio elasticity (SRE), and present an analytical model that derives three SRSs based on the following assumption: simultaneously existing competitions for both resources A and resources B influence the level of SRE in both sexes differently. Consequently, it is the difference (between two sexes) in the level of their sex ratio elasticity that leads to three different SRS. Our analytical results demonstrate that the elasticity-based model not only reveals a highly plausible mechanism that explains the evolution of SRS in nature, but also offers a novel framework for unifying two major classical theories (i.e., LMC & LRC) in the field of SRS research. PMID:28009000

  7. Sex Ratio Elasticity Influences the Selection of Sex Ratio Strategy

    Science.gov (United States)

    Wang, Yaqiang; Wang, Ruiwu; Li, Yaotang; (Sam) Ma, Zhanshan

    2016-12-01

    There are three sex ratio strategies (SRS) in nature—male-biased sex ratio, female-biased sex ratio and, equal sex ratio. It was R. A. Fisher who first explained why most species in nature display a sex ratio of ½. Consequent SRS theories such as Hamilton’s local mate competition (LMC) and Clark’s local resource competition (LRC) separately explained the observed deviations from the seemingly universal 1:1 ratio. However, to the best of our knowledge, there is not yet a unified theory that accounts for the mechanisms of the three SRS. Here, we introduce the price elasticity theory in economics to define sex ratio elasticity (SRE), and present an analytical model that derives three SRSs based on the following assumption: simultaneously existing competitions for both resources A and resources B influence the level of SRE in both sexes differently. Consequently, it is the difference (between two sexes) in the level of their sex ratio elasticity that leads to three different SRS. Our analytical results demonstrate that the elasticity-based model not only reveals a highly plausible mechanism that explains the evolution of SRS in nature, but also offers a novel framework for unifying two major classical theories (i.e., LMC & LRC) in the field of SRS research.

  8. Cheiloscopy for sex determination

    Directory of Open Access Journals (Sweden)

    Shailesh M Gondivkar

    2009-01-01

    Full Text Available Background: Identification of an individual is a pre-requisite for certification of death and for personal, social and legal reasons. The study of lip-prints (cheiloscopy was thought of as a method of identification of a person. It is safe to assume that cheiloscopy, in its present stage of development, has become a means of criminalistic identification dealing with lip-prints. Objective: The objective of the study was to check for any peculiar lip patterns in relation to the sex of the individual and determine the most common lip patterns in the Indian population. Materials and Methods: This study was conducted on 140 subjects, which included 70 males and 70 females, in the age group of 0-70 years. After applying lip stick evenly, the lip-print of each subject was obtained on a simple bond paper by researcher number 1. The lip-print was then analyzed and interpreted by researcher number 2 to determine the sex of individuals. Results: We found that 67 of the actual 70 lip-prints of females were correctly identified and 65 of the 70 males were correctly diagnosed as males. Type C (47.14% was the most commonly occurring trend in females whereas Type B (70% was the most commonly occurring trend in males. Conclusion: Along with other traditional methods, cheiloscopy can also serve as very important tool in the identification of a person based on the characteristic arrangement of lines appearing on the red part of the lips.

  9. Sex Determination Mechanisms in Fish

    Institute of Scientific and Technical Information of China (English)

    ZHANG Quanqi; SUN Xiaohua; QI Jie; WANG Zhigang; WANG Xinglian; WANG Xubo; ZHAI Teng

    2009-01-01

    In fish, sex determination (SD) system shows high variation. The SD mechanisms include environmental and genetic regulation. The research on SD system and related genes in intensively studied fish species was reviewed. Although some genes have been described as sex-related, only DMRTlbY can be considered as a master sex determination gene and none of them has been util-ized in aquaculture. The variation of fish SD system, the importance of sex-related genes in evolution research and the relations be-tween environmental factors and sex-related genes were also discussed. The fish sex determination mechanism remains largely un-known. Further research needs to be done considering the significance of fish SD studies in basic and applied aspects.

  10. Sense about Sex: Media, Sex Advice, Education and Learning

    Science.gov (United States)

    Attwood, Feona; Barker, Meg John; Boynton, Petra; Hancock, Justin

    2015-01-01

    The media are widely acknowledged as important in sex and relationship education, but they are usually associated with "bad" effects on young people in contrast to the "good" knowledge represented by more informational and educational formats. In this paper we look at sex advice giving in newspapers, magazines and television in…

  11. Sex ratio variation and sex determination in Urtica dioica

    NARCIS (Netherlands)

    Glawe, Grit Anja

    2006-01-01

    This thesis will first document on variation in progeny sex ratios among individual female plants of Urtica dioica at our field site in Meijendel (Chapter 2). Next, we show that there is also considerable sex ratio variation among male and female flowering shoots in 26 natural populations studied

  12. Sex ratio variation and sex determination in Urtica dioica

    NARCIS (Netherlands)

    Glawe, Grit Anja

    2006-01-01

    This thesis will first document on variation in progeny sex ratios among individual female plants of Urtica dioica at our field site in Meijendel (Chapter 2). Next, we show that there is also considerable sex ratio variation among male and female flowering shoots in 26 natural populations studied (C

  13. Sense about Sex: Media, Sex Advice, Education and Learning

    Science.gov (United States)

    Attwood, Feona; Barker, Meg John; Boynton, Petra; Hancock, Justin

    2015-01-01

    The media are widely acknowledged as important in sex and relationship education, but they are usually associated with "bad" effects on young people in contrast to the "good" knowledge represented by more informational and educational formats. In this paper we look at sex advice giving in newspapers, magazines and television in…

  14. Sex differences in the brain-an interplay of sex steroid hormones and sex chromosomes.

    Science.gov (United States)

    Grgurevic, Neza; Majdic, Gregor

    2016-09-01

    Although considerable progress has been made in our understanding of brain function, many questions remain unanswered. The ultimate goal of studying the brain is to understand the connection between brain structure and function and behavioural outcomes. Since sex differences in brain morphology were first observed, subsequent studies suggest different functional organization of the male and female brains in humans. Sex and gender have been identified as being a significant factor in understanding human physiology, health and disease, and the biological differences between the sexes is not limited to the gonads and secondary sexual characteristics, but also affects the structure and, more crucially, the function of the brain and other organs. Significant variability in brain structures between individuals, in addition to between the sexes, is factor that complicates the study of sex differences in the brain. In this review, we explore the current understanding of sex differences in the brain, mostly focusing on preclinical animal studies.

  15. Sex Disparities in Stroke

    DEFF Research Database (Denmark)

    Dehlendorff, Christian; Andersen, Klaus Kaae; Olsen, Tom Skyhøj

    2015-01-01

    BACKGROUND: Uncertainty remains about whether stroke affects men and women similarly. We studied differences between men and women with regard to stroke severity and survival. METHODS AND RESULTS: We used the Danish Stroke Registry, with information on all hospital admissions for stroke in Denmark...... between 2003 and 2012 (N=79 617), and the Danish Register of Causes of Death. Information was available on age, sex, marital status, stroke severity, stroke subtype, socioeconomic status, and cardiovascular risk profile. We studied only deaths due to the index stroke, with the assumption that death...... reported on death certificates as due to stroke was related to the index stroke if death occurred within the first week or month after stroke. Multivariate Cox regression analysis and multiple imputation were applied. Stroke was the cause of death for 4373 and 5512 of the 79 617 patients within 1 week (5...

  16. Hepatitis C and sex.

    Science.gov (United States)

    Page, Emma E; Nelson, Mark

    2016-04-01

    An outbreak of acute hepatitis C among HIV-positive men who have sex with men (MSM) in the last decade has been shown to be sexually transmitted. Initially recreational drug use, in particular drug injection, was not prevalent among those becoming infected with hepatitis C. However more recently chemsex (the use of drugs to enhance sexual experience) and its associated drugs, which are not uncommonly injected, have become more frequently reported among those diagnosed with hepatitis C. It is hoped that the widespread -introduction of direct-acting antivirals and upscaling of numbers treated may have a positive impact on this epidemic. However their introduction may negatively impact on the perceived risk of acquiring hepatitis C and in conjunction with the introduction of HIV transmission prevention strategies may result in increased transmissions and spread to the HIV-negative MSM population.

  17. Sex in the Workplace

    Institute of Scientific and Technical Information of China (English)

    村边

    1996-01-01

    读西方出版物上写Sex的文章,我们的心难免会“咯噔”一下。而Sex in the Workplace(工作场合的性)一文却别开生面,值得一读。近年来,工作场合的“性骚扰”(Sexual Harassment)问题的议论也时占我报刊一隅,然比较而言,Sex in the Workplace一文剖精析微、辨证全面,更具警策性。诸如,文章谈及——As a woman, you’re responsible for the signals you send. And when you wear revealing miniskirts, the message men get is ’Look at me.’女性在工作场合着超短裙被认定不宜,本文对男性提出独到的劝言——Just as men often respond intensely to what women wear, women often react strongly to what men say. 在body language(身势语)一节,文章提及女性有25种以上的姿势在男性心目中是provocative(具有挑逗性)的;本文还认为:work intimacy(工作亲密)≠sexual intimacy(性亲密);末尾,本文提出:Before you tell a risque(有伤风化的)joke, ask yourself how your mother or wife might react. If you are wondering whether you should buy an off-color(黄色下流的)card for a male colleague, think about how your father or husband might feel. 这两句议论倒让读者联想到汉语“苦口婆心”之说。 全

  18. Mixed-Sex or Single-Sex Education: How Would Young People Like Their Sex Education and Why?

    Science.gov (United States)

    Strange, Vicki; Forrest, Simon; Oakley, Ann

    2003-01-01

    Examined adolescents views about sex education, specifically their views about interaction in single- and mixed-sex groups. Surveys of English secondary school students indicated that most girls, and one-third of boys, want some or all of their sex education to be delivered in single-sex groups. Girls' experiences of sex education with boys…

  19. Low Sex Drive in Women

    Science.gov (United States)

    Diseases and Conditions Low sex drive in women By Mayo Clinic Staff A woman's sexual desire naturally fluctuates over the years. Highs and lows commonly ... and anti-seizure medications also can cause low sex drive in women. If you have a persistent ...

  20. Sex Hormones and Ischemic Stroke

    DEFF Research Database (Denmark)

    Holmegard, Haya N; Nordestgaard, Børge G; Jensen, Gorm B

    2016-01-01

    CONTEXT AND OBJECTIVE: Whether endogenous sex hormones are associated with ischemic stroke (IS) is unclear. We tested the hypothesis that extreme concentrations of endogenous sex hormones are associated with risk of IS in the general population. DESIGN, SETTING, AND PARTICIPANTS: Adult men (n...

  1. Sex steroids and lipoprotein metabolism

    NARCIS (Netherlands)

    Gevers Leuven, J.A.

    1994-01-01

    Lipoprotein metabolism is involved in atherogenesis. Female sex-hormones have substantial effects on both lipoprotein metabolism and the vessel wall. Cholesterol, one of the major lipids in lipoproteins, is both the substrate for, and the target of, the steroidal sex hormones.

  2. [Sex-linked juvenile retinoschisis].

    Science.gov (United States)

    François, P; Turut, P; Soltysik, C; Hache, J C

    1976-02-01

    About 13 observations of sexe linked juvenile retinoschisis, the authors describe the ophthalmoscopic, fluorographic and functional aspects of the disease whose caracteristics are:--its sexe linked recessive heredity; --its clinical characterestics associating: a microcystic macular degeneration, peripheral retinal lesions, vitreous body alterations, --an electroretinogram of the negative type.

  3. Sex Differences and Individual Differences

    Science.gov (United States)

    Plomin, Robert; Foch, Terryl T.

    1981-01-01

    Sex differences and their relationship to individual differences were examined for Maccoby and Jacklin's sex differences summaries, for a diverse set of measures of specific cognitive abilities (including verbal ability), and for objective personality assessments of 216 school-age children. Average differences between groups appeared to be trivial…

  4. Sex Differences in Dichotic Listening

    Science.gov (United States)

    Voyer, Daniel

    2011-01-01

    The present study quantified the magnitude of sex differences in perceptual asymmetries as measured with dichotic listening. This was achieved by means of a meta-analysis of the literature dating back from the initial use of dichotic listening as a measure of laterality. The meta-analysis included 249 effect sizes pertaining to sex differences and…

  5. Teaching Sex Education in Thailand

    Science.gov (United States)

    Kay, Noy S.; Jones, Megan R.; Jantaraweragul, Sudgasame

    2010-01-01

    The purposes of this study were to examine the current situation pertaining to the teaching of sex education and identify barriers to teaching sex education among Thai health education teachers. A survey questionnaire was administered to 193 health education teachers who participated in this study. The questionnaire was comprised of three parts:…

  6. Moral Pluralism and Sex Education

    Science.gov (United States)

    Corngold, Josh

    2013-01-01

    How should common schools in a liberal pluralist society approach sex education in the face of deep disagreement about sexual morality? Should they eschew sex education altogether? Should they narrow its focus to facts about biology, reproduction, and disease prevention? Should they, in addition to providing a broad palette of information about…

  7. Sex differences in primary hypertension

    Science.gov (United States)

    2012-01-01

    Men have higher blood pressure than women through much of life regardless of race and ethnicity. This is a robust and highly conserved sex difference that it is also observed across species including dogs, rats, mice and chickens and it is found in induced, genetic and transgenic animal models of hypertension. Not only do the differences between the ovarian and testicular hormonal milieu contribute to this sexual dimorphism in blood pressure, the sex chromosomes also play a role in and of themselves. This review primarily focuses on epidemiological studies of blood pressure in men and women and experimental models of hypertension in both sexes. Gaps in current knowledge regarding what underlie male-female differences in blood pressure control are discussed. Elucidating the mechanisms underlying sex differences in hypertension may lead to the development of anti-hypertensives tailored to one's sex and ultimately to improved therapeutic strategies for treating this disease and preventing its devastating consequences. PMID:22417477

  8. Constructions of Sex and Gender

    DEFF Research Database (Denmark)

    Schleicher, Marianne

    2011-01-01

    Responding to the ethical and performative call of Judith Butler not to propagate the sex- and gender-related violence of the imbedded discourse that we study, this article inquires into the discursive strategies of Jewish scripture by analysing how it orchestrates certain norms of sex and gender...... and make them serve the overall aim of securing cultural survival. Following this, it traces reflections on persons of ambiguous or indeterminate sex from rabbinic to modern Judaism so as to inquire into the rabbinic dependency on scripture when non-conforming individuals challenge its bipolar sex...... Jews and non-Jews are able to influence their own representations of sex and gender and thus liberate themselves from the normativity implied by scriptural discourse....

  9. Sex reassignment surgery

    Directory of Open Access Journals (Sweden)

    Bižić Marta

    2015-01-01

    Full Text Available Transsexualism, or gender incongruence, presents a state in which a person's assigned sex at birth conflicts with their psychological gender. It is classified in International Classification of Diseases as F64. Treating these persons require multidisciplinary approach, including psychiatrist, endocrinologist, gynecologist, urologist, plastic and reconstructive surgeon. Genital reconstruction is the final step in transition, and can be performed when all other conditions required by World Professional Association for Transgender Health (WPATH are accomplished. Female to male sex reassignment surgery Several surgical procedures can be done in female to male transsexuals, including mastectomy, removal of female genitalia, metoidioplasty, scrotoplasty with implantation of testicular implants, as well as total phalloplasty. The current operative technique of metoidioplasty comprise the following steps: vaginal removal, the release of the ventral chordee and clitoral ligaments, straightening and lengthening of the clitoris, urethroplasty by combining buccal mucosa graft and genital flaps and scrotoplasty with insertion of testicle prostheses. The goal is to perform all these procedures in one stage, and that makes our team famous worldwide. Metoidioplasty results in excellent cosmetic outcome with completely preserved sensitivity and sexual arousal, enables voiding while standing, but without ability to penetrate due to small size of the neophallus. Considering these advantages, including low complication rate, patients often choose this option. For those who require bigger phallus which enables implantation of penile prosthesis, several surgical techniques have been reported using either available local vascularized tissue or microvascular tissue transfer. However, none of them satisfy all the goals of modern penile construction, i.e. reproducibility, tactile and erogenous sensation, a competent neourethra with a meatus at the top of the neophallus

  10. Same sex families and children

    Directory of Open Access Journals (Sweden)

    Mršević Zorica

    2009-01-01

    Full Text Available Introduction comprises the information on two main forms of same sex families, civic partnership (same sex partnership and same sex marriage. Countries and various status modalities of legal regulations are mentioned. The main part of the text is dedicated to presentation of the findings of the most recent research on various aspects regarding children of same sex partnerships. It comprises presentations grouped in four main chapters: acceptance of same sex partnerships, acceptance of legal recognition of the same sex partnerships, family plans of homosexual teenagers, and raising children within and by the same sex partners. Also the real life cases mirroring legal changes through their life destinies are presented, such is e.g. the Irish way to legalization of the same sex partnerships. In addition, a love story of two women crowned by giving birth of their four children is mentioned. Reasons against and negative reactions the author puts under the title Homophobia. In the Concluding remarks, the author presents the most recent examples of legal changes happened in Norway, Ecuador, and in the American states of California and Connecticut. It was also stated that in European countries of low birth rate, the same sex families are inevitably identified as one of demographically valuable source of creating and raising children, which is worthy to be supported, rather than being hindered without reason and discriminated. Although different than a model of heterosexual family, same sex partnerships neither are harrowing to traditional family values, nor reflex of any kind of promiscuous, antisocial behavior, avoidance of parenthood, and negation of family. Quite opposite, these families are an outcome of endeavors of homosexuals not to be deprived of family, parenthood and all of other values of stabile, monogamous, emotional/sexual socially accepted and legally recognized and regulated conventional family. .

  11. Talk to Your Kids about Sex

    Science.gov (United States)

    ... Topic En español Talk to Your Kids about Sex Browse Sections The Basics Overview Bodies and Puberty ... healthy expectations for their relationships. Talk about opposite-sex and same-sex relationships. When you talk about ...

  12. Sex Education: Talking to Your Teen about Sex

    Science.gov (United States)

    ... contraception and safe sex. The doctor may also stress the importance of routine human papillomavirus (HPV) vaccination, for both girls and boys, to help prevent genital warts as well as cancers of the cervix, anus, ...

  13. Sex in the brain: hormones and sex differences.

    Science.gov (United States)

    Marrocco, Jordan; McEwen, Bruce S

    2016-12-01

    Contrary to popular belief, sex hormones act throughout the entire brain of both males and females via both genomic and nongenomic receptors. Many neural and behavioral functions are affected by estrogens, including mood, cognitive function, blood pressure regulation, motor coordination, pain, and opioid sensitivity. Subtle sex differences exist for many of these functions that are developmentally programmed by hormones and by not yet precisely defined genetic factors, including the mitochondrial genome. These sex differences, and responses to sex hormones in brain regions and upon functions not previously regarded as subject to such differences, indicate that we are entering a new era in our ability to understand and appreciate the diversity of gender-related behaviors and brain functions.

  14. Whose crazy investment in sex?

    Science.gov (United States)

    Mandlis, Lane R

    2011-01-01

    By probing the processes of exclusion of transsexuals from the political sphere, this article offers contributions to social and political theory through an examination of the processes of exclusion from the category "human." This article considers how the erasure of investment in their own embodied sex constructs a platform from which to blame others for sex/gender variance, as well as to justify that blaming. Bringing together Giorgio Agamben, Georges Bataille, Judith Butler, and Nikolas Rose with transphobia, medicalization in psychiatry, law, and ethopolitics, this article questions whose investment in sexed embodiment counts and why that investment might be seen as "crazy."

  15. Disentangling the benefits of sex.

    Science.gov (United States)

    Roze, Denis

    2012-01-01

    Understanding the evolutionary advantage of sexual reproduction remains one of the most fundamental questions in evolutionary biology. Most of the current hypotheses rely on the fact that sex increases genetic variation, thereby enhancing the efficiency of natural selection; an important body of theoretical work has defined the conditions under which sex can be favoured through this effect. Over the last decade, experimental evolution in model organisms has provided evidence that sex indeed allows faster rates of adaptation. A new study on facultatively sexual rotifers shows that increased rates of sex can be favoured during adaptation to new environmental conditions and explores the cause of this effect. The results provide support for the idea that the benefits of increasing genetic variation may compensate for the short-term costs of sexual reproduction.

  16. Same-Sex Partner Bereavement.

    Science.gov (United States)

    Patlamazoglou, Lefteris; Simmonds, Janette G; Snell, Tristan L

    2017-01-01

    The experience of same-sex-attracted people who have lost a partner is neglected in the existing literature on bereavement. Previous research on lesbian, gay, bisexual, transgender, intersex, queer and questioning (LGBTIQ) populations tends to focus on the loss of a partner to HIV-related causes, and there is scant research concerning non-HIV-related bereavement. The purpose of this article is to investigate the non-HIV-related bereavement experiences of same-sex partners and to address the potential complications of disenfranchised grief. Coping with the loss of a same-sex partner and the impact of bereavement on subsequent relationships are also discussed. Implications for counseling of bereaved same-sex-attracted individuals are drawn, and recommendations for future psychological research on the experience of bereavement are made.

  17. Why sex differences in schizophrenia?

    Institute of Scientific and Technical Information of China (English)

    Rena Li; Xin Ma; Gang Wang; Jian Yang; Chuanyue Wang

    2016-01-01

    Clinical observation shows that men and women are different in prevalence, symptoms, and responses to treatment of several psychiatric disorders, including schizophrenia. While the etiology of gender differences in schizophrenia is only partially understood, recent genetic studies suggest significant sex-specific pathways in the schizophrenia between men and women. More research is needed to understand the causal roles of sex differences in schizophrenia in order to ultimately develop sex-specific treatment of this seri-ous mental illness. In the present review, we will out-line the current evidence on the sex-related factors in-teraction with disease onset, symptoms and treatment of schizophrenia, and discuss the potential molecular mechanisms that may mediate their cooperative actions in schizophrenia pathogenesis.

  18. Sex and Sexuality and HIV

    Science.gov (United States)

    ... DO protect against HIV: abstinence (not having sex) male condom female condom Birth control options that DO NOT protect against HIV: oral contraceptive ("the pill") Depo-Provera (shot) emergency contraception ("morning- ...

  19. Sex Inversion Operations in China

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    IN July 1992, Dr. Xia Zhaoji, 58, and his assistants surprised the world by successfully completing the world’s first operation to partially replant human internal reproductive organs. BBC broadcast this 8-minute news story ten days later, followed by AP, Reuters and AFP, as well as some other domestic and international media. What is a sex inversion operation? Why should people change their sex? And how is it

  20. A Review of The Sex EDcyclopedia

    Science.gov (United States)

    Herman, Jeff; Andelloux, Megan

    2012-01-01

    While virtually all sex education books for teenagers focus on sexual health, Jo Langford's "The Sex EDcyclopedia" offers comprehensive and empowering information specifically for teen males about their sexuality and how it may be positively experienced. This review examines the strengths of "The Sex EDcyclopedia" as a sex education resource and…

  1. Sex trade among men: negotiating sex, bodies and identity categories

    Directory of Open Access Journals (Sweden)

    Murilo dos Santos Moscheta

    2013-01-01

    Full Text Available Commercial sex is a marginalized and highly stigmatized activity in Brazilian culture. In this article we aim at investigating the discursive strategies used by young men who trade sex in order to resist stigmatization and social exclusion. We interviewed 24 young men who trade sex in a medium sized city in Brazil. Discursive strategies used by the interviewees to avoid social stigma could be summarized as (1 a reduction of sexual activity to its commercial sense by employing a conceptualization of masculinity that focuses on moral values and disregards sexual intercourse, (2 an emphasis on the anatomic characteristics as a criterion to delimit sexual identification categories, and (3 a shifting of sexual systems from one based on sexual object choice to one based on sexual aim. The discussion highlights that the interviewees were actively negotiating with normative assumptions of sexuality and thus producing either its subversion or conservation.

  2. Sex determination using maxillary sinus

    Directory of Open Access Journals (Sweden)

    Ranjith Kumar Kanthem

    2015-01-01

    Full Text Available Background: Individual identification is a subtle concept and often one of the most important priorities in mass disasters, road accidents, air crashes, fires, and even in the investigation of criminal cases. Matching specific features detected on the cadaver with data recorded during the life of an individual is an important aspect in forensics, and can be performed by fingerprint analysis, deoxyribonucleic acid matching, anthropological methods, radiological methods and other techniques which can facilitate age and sex identification. Sinus radiography is one such method that has been used for determination of the sex of an individual. Hence, an attempt is being made to use the different dimensions of the maxillary sinus in the determination of sex using coronal and axial sections of plain computed tomography (CT scan. Materials and Methods: A total of 30 patients including 17 male and 13 female, visiting the Outpatient Department of the Mamata General Hospital were included as the study subjects. The dimensions of right and left maxillary sinuses of 30 subjects from plain CT were measured using SYNGO software and statistical analysis was done. Results: Sex determination using height, length, width, and volume of the maxillary sinus on both sides showed statistically significant results with a higher percentage of sexual dimorphism in the case of volume. Conclusion: Volume of the right maxillary sinus can be used as accurate diagnostic parameter for sex determination.

  3. A reconfiguration of the sex trade

    DEFF Research Database (Denmark)

    Elmes, Jocelyn; Skovdal, Morten; Nhongo, Kundai

    2017-01-01

    dispersed from the bars into the wider community, requiring female sex workers to employ different tactics to attract clients. Hyperinflation meant that sex workers had to accept new forms of payment, including sex-on-credit and commodities. Further impacting the demand for commercial sex work was a poverty...... and respond to the contribution of sex work to HIV transmission need to guard against unduly static definitions and consider the changing socioeconomic context and how this can cause shifts in behavior....

  4. Population consequences of environmental sex reversal.

    OpenAIRE

    Cotton, S.; Wedekind, C

    2009-01-01

    When sex determination in a species is predominantly genetic but environmentally reversible, exposure to (anthropogenic) changes in the environment can lead to shifts in a population's sex ratio. Such scenarios may be common in many fishes and amphibians, yet their ramifications remain largely unexplored. We used a simple model to study the (short-term) population consequences of environmental sex reversal (ESR). We examined the effects on sex ratios, sex chromosome frequencies, and populatio...

  5. Tackling the diversity of sex determination.

    Science.gov (United States)

    Wedekind, Claus; Stelkens, Rike B

    2010-02-23

    A workshop on 'The evolution of sex determination systems' was held at a remote place in the Swiss Alps from 17 to 20 June 2009. It brought together theoreticians and empiricists, the latter ranging from molecular geneticists to evolutionary ecologists, all trying to understand key aspects of sex determination. The topics discussed included the evolutionary origins of sex determination, the diversity of sex determination mechanisms in different taxa, and the transition from genotypic to environmental sex determination and vice versa.

  6. The Stability of Same-Sex Cohabitation, Different-Sex Cohabitation, and Marriage

    Science.gov (United States)

    Lau, Charles Q.

    2012-01-01

    This study contributes to the emerging demographic literature on same-sex couples by comparing the level and correlates of union stability among 4 types of couples: (a) male same-sex cohabitation, (b) female same-sex cohabitation, (c) different-sex cohabitation, and (d) different-sex marriage. The author analyzed data from 2 British birth cohort…

  7. [Pili annulati. A scanning electron microscopy study].

    Science.gov (United States)

    Lalević-Vasić, B; Polić, D

    1988-01-01

    A case of ringed hair studied by light and electron microscopy is reported. The patient, a 20-year old girl, had been presenting with the hair abnormality since birth. At naked eye examination the hairs were dry, 6 to 7 cm long, and they showed dull and shining areas giving the scalp hair a scintillating appearance (fig. 1). Several samples of hair were taken and examined by light microscopy under white and polarized light. Hair shafts and cryo-fractured surfaces were examined by scanning electron microscopy. RESULTS. 1. Light microscopy. Lesions were found in every hair examined. There were abnormal, opaque and fusiform areas alternating with normal areas all along the hair shaft (fig. 2). The abnormal areas resulted from intracortical air-filled cavities. Fractures similar to those of trichorrhexis nodosa were found in the opaque areas of the distal parts of the hairs. 2. Scanning electron microscopy. A. Hair shaft surface. The abnormal areas showed a longitudinal, "curtain-like" folding of the cuticular cells which had punctiform depressions on their surface and worn free edges (fig. 4, 5, 6); trichorrhexis-type fractures were seen in the distal parts of the hair shafts (fig. 7, 8). Normal areas regularly presented with longitudinal, superficial, short and non-systematized depressions (fig. 9); the cuticular cells were worn, and there were places where the denuded cortex showed dissociated cortical fibres (fig. 10).(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Sex hormone binding globulin phenotypes

    DEFF Research Database (Denmark)

    Cornelisse, M M; Bennett, Patrick; Christiansen, M

    1994-01-01

    Human sex hormone binding globulin (SHBG) is encoded by a normal and a variant allele. The resulting SHBG phenotypes (the homozygous normal SHBG, the heterozygous SHBG and the homozygous variant SHBG phenotype) can be distinguished by their electrophoretic patterns. We developed a novel detection....... This method of detection was used to determine the distribution of SHBG phenotypes in healthy controls of both sexes and in five different pathological conditions characterized by changes in the SHBG level or endocrine disturbances (malignant and benign ovarian neoplasms, hirsutism, liver cirrhosis...... on the experimental values. Differences in SHBG phenotypes do not appear to have any clinical significance and no sex difference was found in the SHBG phenotype distribution....

  9. Destabilising Sex work and Intimacy?

    DEFF Research Database (Denmark)

    Spanger, Marlene

    politikfelt prostitution. Undersøgelsen trækker på poststrukturalistisk feministisk teori og er baseret på interviews med kvindelige thailandske migranter, der sælger sex, og socialarbejdere samt deltagende observationer og diverse dokumenter. Afhandlingen falder i to dele. Den første del er rammen for de...... fire artikler, som består af en introduktion, en teoretisk ramme, metodeovervejelser og konklusion samt et overordnet forskningsspørgsmål: Hvordan destabiliserer og reproducerer kvindelige thailandske migranter, der sælger sex i Danmark, det danske prostitutionspolitikfelts kategorier ’sexarbejde’ og...

  10. SExSeg: SExtractor segmentation

    Science.gov (United States)

    Coe, Dan

    2015-08-01

    SExSeg forces SExtractor (ascl:1010.064) to run using a pre-defined segmentation map (the definition of objects and their borders). The defined segments double as isophotal apertures. SExSeg alters the detection image based on a pre-defined segmenation map while preparing your "analysis image" by subtracting the background in a separate SExtractor run (using parameters you specify). SExtractor is then run in "double-image" mode with the altered detection image and background-subtracted analysis image.

  11. Elusive Sex Acts: Pleasure and Politics in Norwegian Sex Education

    Science.gov (United States)

    Svendsen, Stine H. Bang

    2012-01-01

    While there is little political opposition towards sex education as such in Norway, recent attempts at reforming the subject reveal underlying heteronormative presumptions that seem resistant to reform. While a focus on homosexuality is included in the national curriculum at all levels of compulsory education, the sexual practices involved in…

  12. Learning about Sex: Resource Guide for Sex Educators. Revised Edition

    Science.gov (United States)

    Huberman, Barbara

    2011-01-01

    Whether you are someone new to the field of sex education, trying to start a library or resource center on adolescent sexual health, or an old pro, this guide should give you a basic orientation to what's available to support your work. These resources are important to advancing positive attitudes toward adolescent sexual health and the author…

  13. Sex Equity and Sexuality in College Level Sex Education Courses.

    Science.gov (United States)

    Myerson, Marilyn

    1987-01-01

    This article examines two relevant features in the historical development of sexology, the body of knowledge upon which sex education is based: its depoliticization of sexuality and its attempts to ground itself as scientific. Also examined are the sexual politics of sexology, via a content analysis of several college texts. (IAH)

  14. Elusive Sex Acts: Pleasure and Politics in Norwegian Sex Education

    Science.gov (United States)

    Svendsen, Stine H. Bang

    2012-01-01

    While there is little political opposition towards sex education as such in Norway, recent attempts at reforming the subject reveal underlying heteronormative presumptions that seem resistant to reform. While a focus on homosexuality is included in the national curriculum at all levels of compulsory education, the sexual practices involved in…

  15. Numerous transitions of sex chromosomes in Diptera.

    Science.gov (United States)

    Vicoso, Beatriz; Bachtrog, Doris

    2015-04-01

    Many species groups, including mammals and many insects, determine sex using heteromorphic sex chromosomes. Diptera flies, which include the model Drosophila melanogaster, generally have XY sex chromosomes and a conserved karyotype consisting of six chromosomal arms (five large rods and a small dot), but superficially similar karyotypes may conceal the true extent of sex chromosome variation. Here, we use whole-genome analysis in 37 fly species belonging to 22 different families of Diptera and uncover tremendous hidden diversity in sex chromosome karyotypes among flies. We identify over a dozen different sex chromosome configurations, and the small dot chromosome is repeatedly used as the sex chromosome, which presumably reflects the ancestral karyotype of higher Diptera. However, we identify species with undifferentiated sex chromosomes, others in which a different chromosome replaced the dot as a sex chromosome or in which up to three chromosomal elements became incorporated into the sex chromosomes, and others yet with female heterogamety (ZW sex chromosomes). Transcriptome analysis shows that dosage compensation has evolved multiple times in flies, consistently through up-regulation of the single X in males. However, X chromosomes generally show a deficiency of genes with male-biased expression, possibly reflecting sex-specific selective pressures. These species thus provide a rich resource to study sex chromosome biology in a comparative manner and show that similar selective forces have shaped the unique evolution of sex chromosomes in diverse fly taxa.

  16. Numerous transitions of sex chromosomes in Diptera.

    Directory of Open Access Journals (Sweden)

    Beatriz Vicoso

    2015-04-01

    Full Text Available Many species groups, including mammals and many insects, determine sex using heteromorphic sex chromosomes. Diptera flies, which include the model Drosophila melanogaster, generally have XY sex chromosomes and a conserved karyotype consisting of six chromosomal arms (five large rods and a small dot, but superficially similar karyotypes may conceal the true extent of sex chromosome variation. Here, we use whole-genome analysis in 37 fly species belonging to 22 different families of Diptera and uncover tremendous hidden diversity in sex chromosome karyotypes among flies. We identify over a dozen different sex chromosome configurations, and the small dot chromosome is repeatedly used as the sex chromosome, which presumably reflects the ancestral karyotype of higher Diptera. However, we identify species with undifferentiated sex chromosomes, others in which a different chromosome replaced the dot as a sex chromosome or in which up to three chromosomal elements became incorporated into the sex chromosomes, and others yet with female heterogamety (ZW sex chromosomes. Transcriptome analysis shows that dosage compensation has evolved multiple times in flies, consistently through up-regulation of the single X in males. However, X chromosomes generally show a deficiency of genes with male-biased expression, possibly reflecting sex-specific selective pressures. These species thus provide a rich resource to study sex chromosome biology in a comparative manner and show that similar selective forces have shaped the unique evolution of sex chromosomes in diverse fly taxa.

  17. Sex-biased gene expression at homomorphic sex chromosomes in emus and its implication for sex chromosome evolution.

    Science.gov (United States)

    Vicoso, Beatriz; Kaiser, Vera B; Bachtrog, Doris

    2013-04-16

    Sex chromosomes originate from autosomes. The accumulation of sexually antagonistic mutations on protosex chromosomes selects for a loss of recombination and sets in motion the evolutionary processes generating heteromorphic sex chromosomes. Recombination suppression and differentiation are generally viewed as the default path of sex chromosome evolution, and the occurrence of old, homomorphic sex chromosomes, such as those of ratite birds, has remained a mystery. Here, we analyze the genome and transcriptome of emu (Dromaius novaehollandiae) and confirm that most genes on the sex chromosome are shared between the Z and W. Surprisingly, however, levels of gene expression are generally sex-biased for all sex-linked genes relative to autosomes, including those in the pseudoautosomal region, and the male-bias increases after gonad formation. This expression bias suggests that the emu sex chromosomes have become masculinized, even in the absence of ZW differentiation. Thus, birds may have taken different evolutionary solutions to minimize the deleterious effects imposed by sexually antagonistic mutations: some lineages eliminate recombination along the protosex chromosomes to physically restrict sexually antagonistic alleles to one sex, whereas ratites evolved sex-biased expression to confine the product of a sexually antagonistic allele to the sex it benefits. This difference in conflict resolution may explain the preservation of recombining, homomorphic sex chromosomes in other lineages and illustrates the importance of sexually antagonistic mutations driving the evolution of sex chromosomes.

  18. Same Sex Marriage and the Perceived Assault on Opposite Sex Marriage

    OpenAIRE

    Alexis Dinno; Chelsea Whitney

    2013-01-01

    BACKGROUND: Marriage benefits both individuals and societies, and is a fundamental determinant of health. Until recently same sex couples have been excluded from legally recognized marriage in the United States. Recent debate around legalization of same sex marriage has highlighted for anti-same sex marriage advocates and policy makers a concern that allowing same sex couples to marry will lead to a decrease in opposite sex marriages. Our objective is to model state trends in opposite sex mar...

  19. Sex differences in glucose levels

    DEFF Research Database (Denmark)

    Faerch, K; Borch-Johnsen, Knut; Vaag, A

    2010-01-01

    We aimed to examine whether sex differences in fasting plasma glucose (FPG), 2 h post-OGTT plasma glucose (2hPG) and HbA(1c) could be explained by differences in body size and/or body composition between men and women in a general non-diabetic Danish population. Moreover, we aimed to study to what...

  20. Sex and acute stroke presentation.

    Science.gov (United States)

    Labiche, Lise A; Chan, Wenyaw; Saldin, Kamaldeen R; Morgenstern, Lewis B

    2002-11-01

    We determine whether a sex difference exists for acute stroke emergency department presentation. The TLL Temple Foundation Stroke Project is a prospective observational study of acute stroke management that identified 1,189 validated strokes in nonurban community EDs from February 1998 to March 2000. Structured interview of the patient and the person with the patient at symptom onset identified the symptom or symptoms that prompted the patient to seek medical attention. Interview data were available for 1,124 (94%) patients. A physician blinded to sex classified the reported symptoms into 14 categories. Nontraditional stroke symptoms were reported by 28% of women and 19% of men (odds ratio 1.62; 95% confidence interval 1.2 to 2.2). Nontraditional stroke symptoms, pain (men 8%, women 12%) and change in level of consciousness (men 12%, women 17%), were more often reported by women. Traditional stroke symptoms, imbalance (men 20%, women 15%) and hemiparesis (men 24%, women 19%), were reported more frequently by men. Trends were also found for women to present with nonneurologic symptoms (men 17%, women 21%) and men to present with gait abnormalities (men 11%, women 8%). There was no sex difference in the mean number of symptoms reported by an individual patient. This study suggests that a sex difference exists in reporting of acute stroke symptoms. Women with validated strokes present more frequently with nontraditional stroke symptoms than men. Recognition of this difference might yield faster evaluation and management of female patients with acute stroke eligible for acute therapies.

  1. Sex differences in heart failure

    NARCIS (Netherlands)

    Meyer, Sven

    2016-01-01

    This thesis examined differences between men and women with heart failure. First, it was shown that biological sex is a strong modulator in the clinical expression of various cardiomyopathies. In the general population it was shown that men are more likely to develop heart failure with reduced eject

  2. Sex Education in Multicultural Norway

    Science.gov (United States)

    Bartz, Tiffany

    2007-01-01

    Scandinavia has long been admired by American liberals and sex education advocates who cite comparable rates of adolescent sexuality, yet lower rates of teenage pregnancy, sexually transmitted diseases and abortion in Scandinavia. The United States has, however, two variables with which Scandinavia in general, and Norway in particular, has not…

  3. Sex Bias in Counseling Materials

    Science.gov (United States)

    Harway, Michele

    1977-01-01

    This article reviews findings of bias in counseling materials and presents results of three original studies. Indications are that textbooks used by practitioners present the sexes in stereotypical fashion, and a greater proportion of college catalog context is devoted to men than to women. (Author)

  4. Children as Sex Offenders, Why?

    Science.gov (United States)

    Deranek, Traci; Gilman, David A.

    This study investigates juvenile sex offenders and the predetermining factors that are present in their lives, prior to their first offenses. This study will give an overview of theories, children's sexual behaviors ranging from normal to disturbed, and family dynamics of juvenile offenders. The treatment files of boys and young men, currently in…

  5. Facets: Sex and Language Features.

    Science.gov (United States)

    English Journal, 1983

    1983-01-01

    Presents (1) suggestions of a sex-related frequency variation in vocabulary, pronunciation, and grammar; (2) evidence of increased sensitivity to sexist language in the manuscripts submitted to the National Council of Teachers of English; (3) a proposed substitution of "Dear Reader" for "Gentlemen" in business correspondence; and (4) a description…

  6. Sex determination in the Hymenoptera

    NARCIS (Netherlands)

    Heimpel, George E.; de Boer, Jetske G.

    2008-01-01

    The dominant and ancestral mode of sex determination in the Hymenoptera is arrhenotokous parthenogenesis, in which diploid females develop from fertilized eggs and haploid males develop from unfertilized eggs. We discuss recent progress in the understanding of the genetic and cytoplasmic mechanisms

  7. Sex, Lies and Video Games

    Science.gov (United States)

    Kearney, Paul; Pivec, Maja

    2007-01-01

    Sex and violence in video games is a social issue that confronts us all, especially as many commercial games are now being introduced for game-based learning in schools, and as such this paper polls teenage players about the rules their parents and teachers may or may not have, and surveys the gaming community, ie, game developers to parents, to…

  8. Creativity and Psychopathology: Sex Matters

    Science.gov (United States)

    Martín-Brufau, Ramón; Corbalán, Javier

    2016-01-01

    The association between creativity and psychopathology has, for decades, been a focus of heated debate fuelled by contradictory findings. Nevertheless, the findings suggest complex associations between creativity and psychopathology. Other studies have investigated the association between creativity and sex, with inconsistent results. The aim of…

  9. Sex Education in Multicultural Norway

    Science.gov (United States)

    Bartz, Tiffany

    2007-01-01

    Scandinavia has long been admired by American liberals and sex education advocates who cite comparable rates of adolescent sexuality, yet lower rates of teenage pregnancy, sexually transmitted diseases and abortion in Scandinavia. The United States has, however, two variables with which Scandinavia in general, and Norway in particular, has not…

  10. Sex determination in flowering plants.

    Science.gov (United States)

    Dellaporta, S L; Calderon-Urrea, A

    1993-10-01

    In many ways, plants offer unique systems through which to study sex determination. Because the production of unisexual flowers has evolved independently in many plant species, different and novel mechanisms may be operational. Hence, there is probably not one unifying mechanism that explains sex determination in plants. Advances in our understanding of sex determination will come from the analysis of the genetics, molecular biology, and biochemistry of genes controlling sexual determination in plants. Several excellent model systems for bisexual floral development (Arabidopsis and Antirrhinum), monoecy (maize), and dioecy (Silene, asparagus, and mercury) are available for such analyses. The important questions that remain concern the mechanism of action of sex determination genes and their interrelationship, if any, with homeotic genes that determine the sexual identity of floral organ primordia. At the physiological level, the connection between hormone signaling and sexuality is not well understood, although significant correlations have been discovered. Finally, once the genes that regulate these processes are identified, cloned, and studied, new strategies for the manipulation of sexuality in plants should be forthcoming.

  11. Creativity and Psychopathology: Sex Matters

    Science.gov (United States)

    Martín-Brufau, Ramón; Corbalán, Javier

    2016-01-01

    The association between creativity and psychopathology has, for decades, been a focus of heated debate fuelled by contradictory findings. Nevertheless, the findings suggest complex associations between creativity and psychopathology. Other studies have investigated the association between creativity and sex, with inconsistent results. The aim of…

  12. Sex, Lies and Video Games

    Science.gov (United States)

    Kearney, Paul; Pivec, Maja

    2007-01-01

    Sex and violence in video games is a social issue that confronts us all, especially as many commercial games are now being introduced for game-based learning in schools, and as such this paper polls teenage players about the rules their parents and teachers may or may not have, and surveys the gaming community, ie, game developers to parents, to…

  13. Sex, Sexuality, Sexting, and SexEd: Adolescents and the Media

    Science.gov (United States)

    Brown, Jane D.; Keller, Sarah; Stern, Susannah

    2009-01-01

    The traditional media (television, radio, movies, magazines) and new, digital media (the Internet, Social Networking Sites such as Facebook and Myspace, and cell phones) have become important sex educators for adolescents. Adolescents in the United States spend six to seven hours a day with some form of media, often using more than one kind…

  14. Sex, Sexuality, Sexting, and SexEd: Adolescents and the Media

    Science.gov (United States)

    Brown, Jane D.; Keller, Sarah; Stern, Susannah

    2009-01-01

    The traditional media (television, radio, movies, magazines) and new, digital media (the Internet, Social Networking Sites such as Facebook and Myspace, and cell phones) have become important sex educators for adolescents. Adolescents in the United States spend six to seven hours a day with some form of media, often using more than one kind…

  15. How Will Cancer Affect My Sex Life?

    Science.gov (United States)

    ... Patients and Families How will cancer affect my sex life? Sexual feelings and attitudes vary greatly among ... Others find that they have less interest in sex because of the physical and emotional demands of ...

  16. Sex and Prevention Concerns for Positive People

    Science.gov (United States)

    ... with any comments or concerns. February 17, 2011 Sex and prevention concerns for positive people Facebook Twitter ... partner, and vice versa. The reality of safer sex You put yourself at risk for infections through ...

  17. Gambling, Sex, and…Parkinson's Disease?

    Science.gov (United States)

    ... spent, browse our financial information. Learn More Gambling, Sex, and…Parkinson's Disease? By Laura Marsh, M.D. ... and, in people with Parkinson's, most typically involve sex, gambling and abuse of anti-parkinsonian medications. Pathological ...

  18. Sex and the Man With Cancer

    Science.gov (United States)

    ... and Sexual Side Effects in People with Cancer Sex and the Man With Cancer In this guide, ... you and your partner some information about cancer, sex, and sexuality. We cannot answer every question, but ...

  19. Goals for Sex Equitable Sexuality Education.

    Science.gov (United States)

    Whatley, Mariamne H.

    1987-01-01

    This article presents an overview of issues related to sex equity in sexuality education. Goals which might represent sex equitable sexuality education include eliminating double standards, and redefining sexuality education. (IAH)

  20. Sex chromosome rearrangements in Polyphaga beetles.

    Science.gov (United States)

    Dutrillaux, A M; Dutrillaux, B

    2009-01-01

    The presence of a parachute sex chromosome bivalent (Xyp) at metaphase I of male meiosis is a well-known characteristic of Coleoptera, present in almost all families of this order and assumed to represent their ancestral sex chromosome formula. Sex chromosomes appear to be manifold more frequently involved in inter-chromosomal rearrangements than the average of the nine autosomal pairs usually forming their karyotype. This leads to various formulae such as neo-sex, multiple sex and perhaps unique sex chromosomes. These rearrangements alter the intimate association between sex chromosomes and nucleolar proteins, which are usual components of the Xyp. Different situations, selected in a series of 125 mitotic and meiotic cytogenetic studies of Polyphaga beetle species, are reported and discussed, with the aim to improve our knowledge on the mechanisms of sex chromosome rearrangements, the relationships with nucleoli and the consequences on dosage compensation and chromosome segregation.

  1. Sex and Prevention Concerns for Positive People

    Science.gov (United States)

    ... with any comments or concerns. February 17, 2011 Sex and prevention concerns for positive people Facebook Twitter ... partner, and vice versa. The reality of safer sex You put yourself at risk for infections through ...

  2. Sex Ratio at Birth in China

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    The demographic structure of populations,particularly age and sex, has profound consequences for harmonious and sustainable social and economic development. Furthermore, analyzing sex ratios of populations is important in analyzing the development of the status Of women and girls.

  3. The Teacher and Sex Role Stereotyping

    Science.gov (United States)

    Juhasz, Anne McCreary

    1974-01-01

    In this article, selected research findings are presented on sex role learning, sex role stereotyping, in general and in the school setting, the effect of such stereotyping on the student, and some suggestions for the teacher. (Author/JA)

  4. Temperature-dependent sex ratio in a bird

    National Research Council Canada - National Science Library

    Ann Göth; David T Booth

    2005-01-01

    ... smaller. Megapodes possess heteromorphic sex chromosomes like other birds, which eliminates temperature-dependent sex determination, as described for reptiles, as the mechanism behind the skewed sex ratios...

  5. Adoption by same-sex couples

    National Research Council Canada - National Science Library

    Ellen, Mary; Lopata, Casey

    2007-01-01

    ... of the child to deny adoption to same-sex couples? As with opposite sex couples, the answer depends on the particular child and the particular couple involved. And studies show that children in same-sex-headed families do just as well as those in opposite-sex-headed families, and better than children who remain un-adopted. MARY ELLEN and CASEY LOPATA Rocheste...

  6. Abnormal sex chromosome constitution and longitudinal growth

    DEFF Research Database (Denmark)

    Aksglaede, Lise; Skakkebaek, Niels E; Juul, Anders

    2008-01-01

    Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles.......Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles....

  7. Decreasing Human Trafficking through Sex Work Decriminalization.

    Science.gov (United States)

    Albright, Erin; D'Adamo, Kate

    2017-01-01

    In order to decrease human trafficking, health care workers should support the full decriminalization of prostitution. Similar to trafficking in other forms of labor, preventing trafficking in the sex trade requires addressing the different forms of marginalization that create vulnerable communities. By removing punitive laws that prevent reporting of exploitation and abuse, decriminalization allows sex workers to work more safely, thereby reducing marginalization and vulnerability. Decriminalization can also help destigmatize sex work and help resist political, social, and cultural marginalization of sex workers.

  8. Sex trafficking in Nepal: context and process

    OpenAIRE

    Hennink, Monique; Simkhada, Padam

    2004-01-01

    This study has developed a conceptual framework to provide a clearer understanding of the process and context of sex trafficking from Nepal. Quantitative data were analysed from case records of 202 sex-trafficked women at rehabilitation centres in Nepal. In-depth interviews with 42 sex trafficked women, mostly residing at rehabilitation centres in Kathmandu, provide contextual information on the process and circumstances of sex trafficking. The results of this study provide a clearer understa...

  9. Tackling the diversity of sex determination.

    OpenAIRE

    Wedekind, C; Stelkens, R. B.

    2010-01-01

    A workshop on ‘The evolution of sex determination systems’ was held at a remote place in the Swiss Alps from 17 to 20 June 2009. It brought together theoreticians and empiricists, the latter ranging from molecular geneticists to evolutionary ecologists, all trying to understand key aspects of sex determination. The topics discussed included the evolutionary origins of sex determination, the diversity of sex determination mechanisms in different taxa, and the transition from genotypic to envir...

  10. Sex Education Can't Wait

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Teenagers have become sexually mature and active much earlier, leading to rising rates of premarital sex and juvenile pregnancies in China and around the world. As a lack of sex education will put young people in a position that is very vulnerable to sexually transmitted diseases, including HIV/AIDS, we must give them proper knowledge about sex and help them handle sex-related issues wisely.

  11. Climate-driven shifts in adult sex ratios via sex reversals: the type of sex determination matters.

    Science.gov (United States)

    Bókony, Veronika; Kövér, Szilvia; Nemesházi, Edina; Liker, András; Székely, Tamás

    2017-09-19

    Sex reversals whereby individuals of one genetic sex develop the phenotype of the opposite sex occur in ectothermic vertebrates with genetic sex-determination systems that are sensitive to extreme temperatures during sexual differentiation. Recent rises in global temperatures have led researchers to predict that sex reversals will become more common, resulting in the distortion of many populations' sex ratios. However, it is unclear whether susceptibility to climate-driven sex-ratio shifts depends on the type of sex determination that varies across species. First, we show here using individual-based theoretical models that XX/XY (male-heterogametic) and ZZ/ZW (female-heterogametic) sex-determination systems can respond differentially to temperature-induced sex reversals. Interestingly, the impacts of climate warming on adult sex ratio (ASR) depend on the effects of both genotypic and phenotypic sex on survival and reproduction. Second, we analyse the temporal changes of ASR in natural amphibian populations using data from the literature, and find that ASR shifted towards males in ZZ/ZW species over the past 60 years, but did not change significantly in XX/XY species. Our results highlight the fact that we need a better understanding of the interactions between genetic and environmental sex-determining mechanisms to predict the responses of ectotherms to climate change and the associated extinction risks.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'. © 2017 The Author(s).

  12. Sexing the brain: the science and pseudoscience of sex differences.

    Science.gov (United States)

    Rogers, Lesley J

    2010-06-01

    A recent upsurge in unitary biological explanations for gender differences in behavior (i.e. that they are "hard-wired" in the genetic code), put forward not only in books written for a general audience but also in scientific papers, makes it important to examine the fallacies of these ideas. Such genetic and hormonal explanations of human behavior, formulated with little consideration of the influences of experience, and often without taking experience into account at all, are part of a new wave of genetic explanations for a broad range of human behavior, as explained in the paper. These ideas are far from new; moreover, they are pseudoscientific and are used for political influence under the guise of science. They are a conservative social force that maintains social and educational inequalities between women and men. This paper explains that causal explanations of differences between the sexes are of two completely different types: unitary (genetic determinist) versus interactive explanations. The false reasoning used to support genetic determinist explanations of sex differences in behavior is discussed. To illustrate what biology really tells us about gender differentiation, the paper discusses the interactive roles of genetic, hormonal and environmental influences on the development of gender differences. These interactions are illustrated using two model biological systems (e.g. the intertwined influences of genes, sex hormones and experience on the development of sex differences in behavior in rats, and sex differences in neuronal connections in chickens). There is plenty of scientific evidence to show the complex interactive, and ever changing, influences of experience and genes that take place as an organism develops and throughout its life. Malleability of brain and behavior can be shown clearly using animal models, and the processes involved apply also to the development of brain and behavior in humans. We diminish our understanding of the functions of

  13. Sexing the Brain: The Science and Pseudoscience of Sex Differences

    Directory of Open Access Journals (Sweden)

    Lesley J. Rogers

    2010-06-01

    Full Text Available A recent upsurge in unitary biological explanations for gender differences in behavior (i.e. that they are “hard-wired” in the genetic code, put forward not only in books written for a general audience but also in scientific papers, makes it important to examine the fallacies of these ideas. Such genetic and hormonal explanations of human behavior, formulated with little consideration of the influences of experience, and often without taking experience into account at all, are part of a new wave of genetic explanations for a broad range of human behavior, as explained in the paper. These ideas are far from new; moreover, they are pseudoscientific and are used for political influence under the guise of science. They are a conservative social force that maintains social and educational inequalities between women and men. This paper explains that causal explanations of differences between the sexes are of two completely different types: unitary (genetic determinist versus interactive explanations. The false reasoning used to support genetic determinist explanations of sex differences in behavior is discussed. To illustrate what biology really tells us about gender differentiation, the paper discusses the interactive roles of genetic, hormonal and environmental influences on the development of gender differences. These interactions are illustrated using two model biological systems (e.g. the intertwined influences of genes, sex hormones and experience on the development of sex differences in behavior in rats, and sex differences in neuronal connections in chickens. There is plenty of scientific evidence to show the complex interactive, and ever changing, influences of experience and genes that take place as an organism develops and throughout its life. Malleability of brain and behavior can be shown clearly using animal models, and the processes involved apply also to the development of brain and behavior in humans. We diminish our understanding

  14. Sex Differences in Assertiveness in College Students

    Science.gov (United States)

    Stebbins, Charles; And Others

    1977-01-01

    Validates the "College Self-Expression Scale." Shows that females are significantly more assertive, and that in one of the criterion situations each sex was significantly more assertive toward members of the same sex than members of the opposite sex. (RL)

  15. 77 FR 73558 - Sex Offender Registration Amendments

    Science.gov (United States)

    2012-12-11

    ... COLUMBIA 28 CFR Part 811 RIN 3225-AA10 Sex Offender Registration Amendments AGENCY: Court Services and... verification of registration information for sex offenders. The proposed rule, if finalized, would permit CSOSA to verify addresses of sex offenders by conducting home visits on its own accord and with its...

  16. The Advantages of Single-Sex Education

    Science.gov (United States)

    Hughes, Teresa A.

    2006-01-01

    Traditionally, single-sex education has been provided in the form of private schooling. Title IX regulations have loosened as a result of the No Child Left Behind Legislation; therefore, public school districts now have the legal right to create single-sex classes or single-sex schools if they deem it to be in the best interest of their students.…

  17. Deleterious mutations and the evolution of sex

    NARCIS (Netherlands)

    Visser, de J.A.G.M.

    1996-01-01


    In spite of decades of intense debate, the evolutionary reasons for sex are still unknown. In the light of the 'two-fold cost of sex' (Maynard Smith 1971; Williams 1975), a plausible short-term advantage to sex must be found to explain its maintenance. At present, two hypotheses seem to

  18. The Promise of Single-Sex Classes

    Science.gov (United States)

    Stotsky, Sandra

    2012-01-01

    Despite the enthusiasm and the absence of definitive research on the pros and cons of single-sex classes, a 2011 article in Science, titled "The Pseudoscience of Single-Sex Schooling," by a new organization called American Council for CoEducational Schooling (ACCES) came out with the astonishing conclusion that single-sex education is…

  19. ``Sex Hormones'' in Secondary School Biology Textbooks

    Science.gov (United States)

    Nehm, Ross H.; Young, Rebecca

    2008-11-01

    This study explores the extent to which the term “sex hormone” is used in science textbooks, and whether the use of the term “sex hormone” is associated with pre-empirical concepts of sex dualism, in particular the misconceptions that these so-called “sex hormones” are sex specific and restricted to sex-related physiological functioning. We found that: (1) all the texts employed the term “sex hormone”; (2) in all texts estrogen is characterized as restricted to females and testosterone is characterized as restricted to males; and (3) in all texts testosterone and estrogen are discussed as exclusively involved in sex-related physiological roles. We conclude that (1) contemporary science textbooks preserve sex-dualistic models of steroid hormones (one sex, one “sex hormone”) that were rejected by medical science in the early 20th century and (2) use of the term “sex hormone” is associated with misconceptions regarding the presence and functions of steroid hormones in male and female bodies.

  20. Sex Stereotypes and Responses to Juvenile Delinquency.

    Science.gov (United States)

    Willemsen, Tineke M.; van Schie, Els C. M.

    1989-01-01

    Describes two studies to test the following hypotheses: (1) delinquent behavior that corresponds to sex stereotypes will be punished more severely; and (2) delinquent behavior that deviates will be evaluated more negatively. Presents model illustrating how sex stereotypes about delinquent behavior lead to sex-related differences in attribution and…

  1. Analyzing Medical Students' Definitions of Sex

    Science.gov (United States)

    Talley, Heather; Cho, Janice; Strassberg, Donald S.; Rullo, Jordan E.

    2016-01-01

    An inaccurate definition of what constitutes sex can negatively impact the sexual health and wellbeing of patients. This study aimed to determine which behaviors medical students consider to be sex. Survey questions about various sexual behaviors were administered to medical students. All participants agreed that penile-vaginal penetration is sex.…

  2. Deleterious mutations and the evolution of sex.

    NARCIS (Netherlands)

    Visser, de J.A.G.M.

    1996-01-01

    In spite of decades of intense debate, the evolutionary reasons for sex are still unknown. In the light of the 'two-fold cost of sex' (Maynard Smith 1971; Williams 1975), a plausible short-term advantage to sex must be found to explain its maintenance. At present, two hypotheses seem to predominate

  3. The Promise of Single-Sex Classes

    Science.gov (United States)

    Stotsky, Sandra

    2012-01-01

    Despite the enthusiasm and the absence of definitive research on the pros and cons of single-sex classes, a 2011 article in Science, titled "The Pseudoscience of Single-Sex Schooling," by a new organization called American Council for CoEducational Schooling (ACCES) came out with the astonishing conclusion that single-sex education is…

  4. Sex differences in intimate relationships

    CERN Document Server

    Palchykov, Vasyl; Kertész, János; Barabási, Albert-László; Dunbar, Robin I M

    2012-01-01

    Social networks have turned out to be of fundamental importance both for our understanding human sociality and for the design of digital communication technology. However, social networks are themselves based on dyadic relationships and we have little understanding of the dynamics of close relationships and how these change over time. Evolutionary theory suggests that, even in monogamous mating systems, the pattern of investment in close relationships should vary across the lifespan when post-weaning investment plays an important role in maximising fitness. Mobile phone data sets provide us with a unique window into the structure of relationships and the way these change across the lifespan. We here use data from a large national mobile phone dataset to demonstrate striking sex differences in the pattern in the gender-bias of preferred relationships that reflect the way the reproductive investment strategies of the two sexes change across the lifespan: these differences mainly reflect women's shifting pattern...

  5. Teacher training for sex education.

    Science.gov (United States)

    Flaherty, C; Smith, P B

    1981-04-01

    The Population Program at Baylor College of Medicine in Houston conducted a 3-year sex education teacher training program in cooperation with the Houston Independent School District. Existing sex education curricula and teacher training programs were reviewed during the project's last year, and working relationships with school personnel and community representatives were established. During the 2nd year contacts with school district personnel were increased. The project director trained 14 teacher trainers from the school district; 8 of the 14 trained a total of 40 teachers from a total of 10 schools. The 72-hour training program (nine 8-hour sessions, 1 day a week) for the teacher trainers was conducted from mid-January through mid-March 1980. Pre- and posttest knowledge and attitude assessments were conducted with trainers and teachers. 3rd year tasks included selecting student curricula, teaching students, evaluating the effectiveness of the teacher training based on classroom performance, and revising the training manual. Project and school personnel carefully discussed the criteria for teacher trainers and teachers. There are 4 learner-directed goals of the training project. They are for the trainees to be comfortable communicating about sexuality; understand factual information about human sexuality and social systems; recognize the influence of their sexual beliefs; values; and attitudes on their behavior; and comprehend the decision making, systems framework of the training. A 200-page training manual was developed. The training focus was to teach participants a comprehensive sex education program, to develop further their skills as trainers, and to provide information and experiences to answer questions about sex education for 8th and 10th grade students.

  6. Sex without sex chromosomes: genetic architecture of multiple loci independently segregating to determine sex ratios in the copepod Tigriopus californicus.

    Science.gov (United States)

    Alexander, H J; Richardson, J M L; Edmands, S; Anholt, B R

    2015-12-01

    Sex-determining systems are remarkably diverse and may evolve rapidly. Polygenic sex-determination systems are predicted to be transient and evolutionarily unstable, yet examples have been reported across a range of taxa. Here, we provide the first direct evidence of polygenic sex determination in Tigriopus californicus, a harpacticoid copepod with no heteromorphic sex chromosomes. Using genetically distinct inbred lines selected for male- and female-biased clutches, we generated a genetic map with 39 SNPs across 12 chromosomes. Quantitative trait locus mapping of sex ratio phenotype (the proportion of male offspring produced by an F2 female) in four F2 families revealed six independently segregating quantitative trait loci on five separate chromosomes, explaining 19% of the variation in sex ratios. The sex ratio phenotype varied among loci across chromosomes in both direction and magnitude, with the strongest phenotypic effects on chromosome 10 moderated to some degree by loci on four other chromosomes. For a given locus, sex ratio phenotype varied in magnitude for individuals derived from different dam lines. These data, together with the environmental factors known to contribute to sex determination, characterize the underlying complexity and potential lability of sex determination, and confirm the polygenic architecture of sex determination in T. californicus.

  7. Sex trafficking in South Asia.

    Science.gov (United States)

    Huda, S

    2006-09-01

    Economic and social inequalities and political conflicts have led to the movement of persons within each country and across the borders in South Asia. Globalization has encouraged free mobility of capital, technology, experts and sex tourism. Illiteracy, dependency, violence, social stigma, cultural stereotypes, gender disparity and endemic poverty, among other factors, place women and children in powerless, non-negotiable situations that have contributed to the emergence and breeding of the cavernous problem of sex trafficking in the entire region. This alarming spread of sex trafficking has fuelled the spread of HIV infection in South Asia, posing a unique and serious threat to community health, poverty alleviation and other crucial aspects of human development. Although the SAARC (South Asian Association for Regional Cooperation) Convention on Trafficking in Women and Children has been an important breakthrough, most of the countries in the region do not have anti-trafficking legislation or means to protect the victims. Countries of the region should make a concerted effort to treat trafficking victims as "victims" of human rights violations in all anti-trafficking strategies and actions.

  8. MODERN TEENAGER (HIGHLANDER AND SEX

    Directory of Open Access Journals (Sweden)

    Oksana Fedyk

    2015-04-01

    Full Text Available The age at which you can start or be sexually active - a very interesting question, which concerned not only parents, but also psychologists. Usually, you can not answer the question of when and to whom to start having sex. However, there are certain statistics that the average age of sexual debut in adolescents - is 15 years for girls and 14 for boys. Now we are talking about European society, about what is happening in Ukraine, particularly in mountainous areas. The fact that the willingness in principle to sexual intercourse is associated with physiological aspects. There is a notion in sexology - sexual constitution. There are several factors play a role, of course, one of which is constitutional, but not always, psychological maturity and sexual constitution, rather, because of the need for sexual constitution in holding intercourse can match. That is, some teens may be physiologically ready for sexual intercourse at 12-13 years, but the question arises: Are they psychologically? And probably we can not give a definite answer to this question, because curiosity taboo in society, which in the majority rejects teen sex, pushing them into early sexual relations. Nevertheless, probably still age readiness and psychological and physiological - is 18-19 years if we are talking about teen sex.

  9. Condom ads promote illicit sex.

    Science.gov (United States)

    Kippley, J F

    1994-01-01

    Written in 1987, this opinion was republished in the wake of US President Bill Clinton's AIDS prevention media campaign promoting condom use which began January 1994, targeted at young adults aged 18-25. The author staunchly opposes condom use even though he admits that people do not consider abstinence from sex to be a serious option for the prevention of HIV/STD infection. He believes that there is no moral use of sex with a condom and that condoms have always been a sign of immorality, be it prostitution, adultery, fornication, or marital contraception. Likewise, the author laments the success enjoyed by Planned Parenthood in achieving the social acceptance of marital contraception and sex outside of marriage. The complete social acceptance of homosexual activity, however, remains to be achieved. Magazines, newspapers, and television receive income in exchange for publishing or airing advertisements. Finding offensive advertisements which promote the use of condoms against HIV infection, the author recommends writing letters of complaint to the responsible media sources. If the television stations or publications in question continue to advertise condoms to the public, stop watching them or end one's subscriptions to the particular printed media. Such action taken collectively among many individuals will reduce product sales and income, and potentially sway corporate policy against condom ads.

  10. Fetal sex and preterm birth.

    Science.gov (United States)

    Challis, J; Newnham, J; Petraglia, F; Yeganegi, M; Bocking, A

    2013-02-01

    Rates of preterm birth vary between different populations and ethnic groups. Epidemiologic studies have suggested that the incidence of preterm birth is also higher in pregnancies carrying a male fetus; the male:female difference is greater in earlier preterm pregnancy. Placental or chorion trophoblast cells from pregnancies with a male fetus produced more pro-inflammatory TNFα in response to LPS stimulation and less anti-inflammatory IL-10 and granulocyte colony stimulating factor (G-CSF) than cells from pregnancies with a female fetus, more prostaglandin synthase (PTGS-2) and less prostaglandin dehydrogenase (PGDH). These results suggest that in the presence of a male fetus the trophoblast has the potential to generate a more pro-inflammatory environment. Maturation of the fetal hypothalamic-pituitary-adrenal axis and expression of placental genes, particularly 11β hydroxysteroid dehydrogenase-2 are also expressed in a sex dependent manner, consistent with the sex-biasing influences on gene networks. Sex differences in these activities may affect clinical outcomes of pre- and post-dates pregnancies and fetal/newborn wellbeing. These factors need consideration in studies of placental function and in the development of personalized strategies for the diagnosis of preterm labor and postnatal health. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Local offspring density and sex ratio affect sex allocation in the great tit

    NARCIS (Netherlands)

    Michler, Stephanie P. M.; Nicolaus, Marion; van der Velde, Marco; Radersma, Reinder; Ubels, Richard; Both, Christiaan; Komdeur, Jan; Tinbergen, Joost M.

    2013-01-01

    The expected fitness gain for offspring of a given sex may depend on local population sex ratio and density. Knowing the influence of such social factors on brood sex ratios may contribute considerably to the understanding of sex allocation in higher vertebrates. For 3 consecutive years, we

  12. The Relationship of Moral Reasoning to Sex Guilt and Sex Experience in College Couples.

    Science.gov (United States)

    Cross, Herbert; D'Augelli, Judith F.

    Seventy-six college couples were interviewed with Kohlberg's moral dilemmas interview, given the Mosher Sex Guilt scale and took a sex experience inventory. Men, women, and couples who were at the law and order stage of moral reasoning were higher on sex guilt than those at other levels of morality. Male sex experience was associated with morality…

  13. Local offspring density and sex ratio affect sex allocation in the great tit

    NARCIS (Netherlands)

    Michler, Stephanie P. M.; Nicolaus, Marion; van der Velde, Marco; Radersma, Reinder; Ubels, Richard; Both, Christiaan; Komdeur, Jan; Tinbergen, Joost M.

    2013-01-01

    The expected fitness gain for offspring of a given sex may depend on local population sex ratio and density. Knowing the influence of such social factors on brood sex ratios may contribute considerably to the understanding of sex allocation in higher vertebrates. For 3 consecutive years, we manipula

  14. Polygenic sex determination system in zebrafish.

    Directory of Open Access Journals (Sweden)

    Woei Chang Liew

    Full Text Available BACKGROUND: Despite the popularity of zebrafish as a research model, its sex determination (SD mechanism is still unknown. Most cytogenetic studies failed to find dimorphic sex chromosomes and no primary sex determining switch has been identified even though the assembly of zebrafish genome sequence is near to completion and a high resolution genetic map is available. Recent publications suggest that environmental factors within the natural range have minimal impact on sex ratios of zebrafish populations. The primary aim of this study is to find out more about how sex is determined in zebrafish. METHODOLOGY/PRINCIPAL FINDINGS: Using classical breeding experiments, we found that sex ratios across families were wide ranging (4.8% to 97.3% males. On the other hand, repeated single pair crossings produced broods of very similar sex ratios, indicating that parental genotypes have a role in the sex ratio of the offspring. Variation among family sex ratios was reduced after selection for breeding pairs with predominantly male or female offspring, another indication that zebrafish sex is regulated genetically. Further examinations by a PCR-based "blind assay" and array comparative genomic hybridization both failed to find universal sex-linked differences between the male and female genomes. Together with the ability to increase the sex bias of lines by selective breeding, these data suggest that zebrafish is unlikely to utilize a chromosomal sex determination (CSD system. CONCLUSIONS/SIGNIFICANCE: Taken together, our study suggests that zebrafish sex is genetically determined with limited, secondary influences from the environment. As we have not found any sign for CSD in the species, we propose that the zebrafish has a polygenic sex determination system.

  15. Same sex marriage and the perceived assault on opposite sex marriage.

    Directory of Open Access Journals (Sweden)

    Alexis Dinno

    Full Text Available BACKGROUND: Marriage benefits both individuals and societies, and is a fundamental determinant of health. Until recently same sex couples have been excluded from legally recognized marriage in the United States. Recent debate around legalization of same sex marriage has highlighted for anti-same sex marriage advocates and policy makers a concern that allowing same sex couples to marry will lead to a decrease in opposite sex marriages. Our objective is to model state trends in opposite sex marriage rates by implementation of same sex marriages and other same sex unions. METHODS AND FINDINGS: Marriage data were obtained for all fifty states plus the District of Columbia from 1989 through 2009. As these marriage rates are non-stationary, a generalized error correction model was used to estimate long run and short run effects of same sex marriages and strong and weak same sex unions on rates of opposite sex marriage. We found that there were no significant long-run or short run effects of same sex marriages or of strong or weak same sex unions on rates of opposite sex marriage. CONCLUSION: A deleterious effect on rates of opposite sex marriage has been argued to be a motivating factor for both the withholding and the elimination of existing rights of same sex couples to marry by policy makers-including presiding justices of current litigation over the rights of same sex couples to legally marry. Such claims do not appear credible in the face of the existing evidence, and we conclude that rates of opposite sex marriages are not affected by legalization of same sex civil unions or same sex marriages.

  16. Meiotic drive and sex determination: molecular and cytological mechanisms of sex ratio adjustment in birds

    OpenAIRE

    2007-01-01

    Differences in relative fitness of male and female offspring across ecological and social environments should favour the evolution of sex-determining mechanisms that enable adjustment of brood sex ratio to the context of breeding. Despite the expectation that genetic sex determination should not produce consistent bias in primary sex ratios, extensive and adaptive modifications of offspring sex ratio in relation to social and physiological conditions during reproduction are often documented. ...

  17. Exploring dynamics of anal sex among female sex workers in Andhra Pradesh

    OpenAIRE

    Saroj Tucker; Rama Krishna; Parimi Prabhakar; Swarup Panyam; Pankaj Anand

    2012-01-01

    Objective: The anal sex among heterosexual couples is on the rise as reported in many scientific studies. Considering that unprotected anal sex has higher risk of human immunodeficiency virus (HIV) transmission than the vaginal sex, we undertook a study to understand the anal sex practices among Female Sex Workers (FSW). Materials and Methods: The study was conducted among FSW attending 11 randomly selected sexually transmitted infection (STI) clinics in Bill and Melinda Gates supported targe...

  18. Population consequences of environmental sex reversal.

    Science.gov (United States)

    Cotton, Samuel; Wedekind, Claus

    2009-02-01

    When sex determination in a species is predominantly genetic but environmentally reversible, exposure to (anthropogenic) changes in the environment can lead to shifts in a population's sex ratio. Such scenarios may be common in many fishes and amphibians, yet their ramifications remain largely unexplored. We used a simple model to study the (short-term) population consequences of environmental sex reversal (ESR). We examined the effects on sex ratios, sex chromosome frequencies, and population growth and persistence after exposure to environmental forces with feminizing or masculinizing tendencies. When environmental feminization was strong, X chromosomes were driven to extinction. Analogously, extinction of normally male-linked genetic factors (e.g., Y chromosomes) was caused by continuous environmental masculinization. Although moderate feminization was beneficial for population growth in the absence of large viability effects, our results suggest that the consequences of ESR are generally negative in terms of population size and the persistence of sex chromosomes. Extreme sex ratios resulting from high rates of ESR also reduced effective population sizes considerably. This may limit any evolutionary response to the deleterious effects of ESR. Our findings suggest that ESR changes population growth and sex ratios in some counter-intuitive ways and can change the predominant factor in sex determination from genetic to fully environmental, often within only a few tens of generations. Populations that lose genetic sex determination may quickly go extinct if the environmental forces that cause sex reversal cease.

  19. Children's Sex and the Happiness of Parents.

    Science.gov (United States)

    Margolis, Rachel; Myrskyla, Mikko

    Demographers are interested in sex preferences for children because they can skew sex ratios and influence population-level fertility, parenting behavior, and family outcomes. Based on parity progression ratios, in most European countries, there are no sex preferences for a first child, but a strong preference for mixed-sex children. We hypothesize that mixed-sex preferences also influence parental happiness. Parents' disappointment with a second child of the same sex as the first could have negative effects for parents and children. We use longitudinal data from the German Socio-Economic Panel and the British Household Panel Study to examine parental happiness by the children's sex and analyze whether these effects differ by parent's sex, age, nativity, and educational attainment. The results are only partially consistent with predictions from parity progression ratios. As expected, parental happiness does not depend on the sex of the first child. We find weak evidence suggesting that two boys decrease happiness, but the findings are not consistent across German and British data or across subpopulations. Moreover, two girls do not reduce happiness. Although sex preferences influence fertility, they appear to have little impact on happiness, perhaps because of unobserved positive factors associated with having same-sex children.

  20. Prevalence and correlates of violence against female sex workers in ...

    African Journals Online (AJOL)

    2014-06-02

    Jun 2, 2014 ... Key words: female sex workers, violence against women, brothel based sex workers, prostitution in Africa .... is the leader of the sex workers. The chairlady serves as ...... and economic challenges that encourage sex work.

  1. Screening Sex: revelando e dissimulando o sexo Screening Sex

    Directory of Open Access Journals (Sweden)

    Linda Williams

    2012-06-01

    Full Text Available Neste texto, procura-se contar a história da exibição do sexo em filmes majoritariamente produzidos nos Estados Unidos no período de quase um século. Ao se perguntar quando, porque e como os Estados Unidos se transformaram de uma cultura que não exibia o sexo em uma que o exibe, a autora insiste no duplo significado do verbo screen (tanto como uma revelação quanto uma dissimulação. Exibir é revelar em uma tela. Mas um segundo e igualmente importante significado, como diz o dicionário é "proteger ou esconder atrás de uma tela". Os filmes tanto revelam como escondem. O artigo analisa a forma como mudanças sociais ocorridas nos Estados Unidos, como, por exemplo, a Revolução sexual dos anos 60 e novas visões a respeito da sexualidade, possibilitaram novas maneiras de representação do sexo no cinema, reorganizando a relação entre o público e o privado. O artigo se pergunta também sobre como nossos corpos e sentidos reagem ao encontro com o sexo na tela, introduzindo a ideia de "saber carnal" (carnal knowledge.In this paper, we try to tell the history of the exhibition of sex in movies mainly produced in the United States in almost a century. Asking when, why and how the United States became - from a culture that did not exhibit sex - into a culture that exhibits it, the author insists in the double sense of the verb to screen (as both a revelation and a dissimulation. To exhibit is to reveal in a screen. But another, and important, sense, as says the dictionary, is "to protect or hide behind a screen". Movies show as well as they reveal. The paper analyzes the way social change in the United States, for example the sexual revolution of the sixties and new views on sexuality allowed new ways of representing sex in the movies, creating a new relation between public and private. The paper also asks how our bodies and senses react to sex in the screen, introducing the idea of "carnal knowledge".

  2. Sex-differences in heritability of BMI

    DEFF Research Database (Denmark)

    Schousboe, K; Willemsen, G; Kyvik, Kirsten Ohm

    2003-01-01

    pairs (including opposite sex pairs) aged 20-29 and 30-39 from eight different twin registries participating in the GenomEUtwin project. Quantitative genetic analyses were conducted and sex differences were explored. Variation in BMI was greater for women than for men, and in both sexes was primarily...... explained by additive genetic variance in all countries. Sex differences in the variance components were consistently significant. Results from analyses of opposite sex pairs also showed evidence of sex-specific genetic effects suggesting there may be some differences between men and women in the genetic...... factors that influence variation in BMI. These results encourage the continued search for genes of importance to the body composition and the development of obesity. Furthermore, they suggest that strategies to identify predisposing genes may benefit from taking into account potential sex specific effects....

  3. Sex differences in the human visual system.

    Science.gov (United States)

    Vanston, John E; Strother, Lars

    2017-01-02

    This Mini-Review summarizes a wide range of sex differences in the human visual system, with a primary focus on sex differences in visual perception and its neural basis. We highlight sex differences in both basic and high-level visual processing, with evidence from behavioral, neurophysiological, and neuroimaging studies. We argue that sex differences in human visual processing, no matter how small or subtle, support the view that females and males truly see the world differently. We acknowledge some of the controversy regarding sex differences in human vision and propose that such controversy should be interpreted as a source of motivation for continued efforts to assess the validity and reliability of published sex differences and for continued research on sex differences in human vision and the nervous system in general. © 2016 Wiley Periodicals, Inc.

  4. Sex work among men who have sex with men and transgender women in Bogotá.

    Science.gov (United States)

    Bianchi, Fernanda T; Reisen, Carol A; Zea, Maria Cecilia; Vidal-Ortiz, Salvador; Gonzales, Felisa A; Betancourt, Fabián; Aguilar, Marcela; Poppen, Paul J

    2014-11-01

    This qualitative study examined sex work among internally displaced male and transgender female sex workers in Bogotá, Colombia. Internal displacement has occurred in Colombia as a result of decades of conflict among armed groups and has created large-scale migration from rural to urban areas. Informed by the polymorphous model of sex work, which posits that contextual conditions shape the experience of sex work, we examined three main research questions. The first dealt with how internal displacement was related to the initiation of sex work; the second concerned the effect of agency on sex worker satisfaction; and the third examined how sex work in this context was related to HIV and other risks. Life history interviews were conducted with 26 displaced individuals who had done sex work: 14 were men who have sex with men and 12 were transgender women (natal males). Findings revealed that many participants began doing sex work in the period immediately after displacement, because of a lack of money, housing, and social support. HIV risk was greater during this time due to limited knowledge of HIV and inexperience negotiating safer sex with clients. Other findings indicated that sex workers who exerted more control and choice in the circumstances of their work reported greater satisfaction. In addition, we found that although many sex workers insisted on condom use with clients, several noted that they would sometimes have unprotected sex for additional money. Specific characteristics affecting the experience of sex work among the transgender women were also discussed.

  5. Characterization of sex determination and sex differentiation genes in Latimeria.

    Directory of Open Access Journals (Sweden)

    Mariko Forconi

    Full Text Available Genes involved in sex determination and differentiation have been identified in mice, humans, chickens, reptiles, amphibians and teleost fishes. However, little is known of their functional conservation, and it is unclear whether there is a common set of genes shared by all vertebrates. Coelacanths, basal Sarcopterygians and unique "living fossils", could help establish an inventory of the ancestral genes involved in these important developmental processes and provide insights into their components. In this study 33 genes from the genome of Latimeria chalumnae and from the liver and testis transcriptomes of Latimeria menadoensis, implicated in sex determination and differentiation, were identified and characterized and their expression levels measured. Interesting findings were obtained for GSDF, previously identified only in teleosts and now characterized for the first time in the sarcopterygian lineage; FGF9, which is not found in teleosts; and DMRT1, whose expression in adult gonads has recently been related to maintenance of sexual identity. The gene repertoire and testis-specific gene expression documented in coelacanths demonstrate a greater similarity to modern fishes and point to unexpected changes in the gene regulatory network governing sexual development.

  6. Characterization of sex determination and sex differentiation genes in Latimeria.

    Science.gov (United States)

    Forconi, Mariko; Canapa, Adriana; Barucca, Marco; Biscotti, Maria A; Capriglione, Teresa; Buonocore, Francesco; Fausto, Anna M; Makapedua, Daisy M; Pallavicini, Alberto; Gerdol, Marco; De Moro, Gianluca; Scapigliati, Giuseppe; Olmo, Ettore; Schartl, Manfred

    2013-01-01

    Genes involved in sex determination and differentiation have been identified in mice, humans, chickens, reptiles, amphibians and teleost fishes. However, little is known of their functional conservation, and it is unclear whether there is a common set of genes shared by all vertebrates. Coelacanths, basal Sarcopterygians and unique "living fossils", could help establish an inventory of the ancestral genes involved in these important developmental processes and provide insights into their components. In this study 33 genes from the genome of Latimeria chalumnae and from the liver and testis transcriptomes of Latimeria menadoensis, implicated in sex determination and differentiation, were identified and characterized and their expression levels measured. Interesting findings were obtained for GSDF, previously identified only in teleosts and now characterized for the first time in the sarcopterygian lineage; FGF9, which is not found in teleosts; and DMRT1, whose expression in adult gonads has recently been related to maintenance of sexual identity. The gene repertoire and testis-specific gene expression documented in coelacanths demonstrate a greater similarity to modern fishes and point to unexpected changes in the gene regulatory network governing sexual development.

  7. Men who advertise for sex.

    Science.gov (United States)

    Lumby, M E

    1978-01-01

    This content analysis of 1,111 paid ads in the Advocate identifies 17 self-descriptive categories in the "Personals" (PER) and "Models, Masseurs, and Escorts" (MME) sections of the "Trader Dick" supplement. Advertisers place primary emphases on sex and masculinity. Among MME, youthfulness, handsomeness, and sexiness are important, promoting versatility in place of specificity when mentioning sexual acts. PER advertisers, however, indicate concerns about age, race, and finding lovers. They also detail specific sexual interests and reject a variety of unacceptable behaviors.

  8. Stripping, Sex, and Popular Culture

    OpenAIRE

    Roach, Catherine M.

    2007-01-01

    At the heart of Stripping, Sex, and Popular Culture lies a very personal story, of author Catherine Roach's response to the decision of her life-long best friend to become an exotic dancer. Catherine and Marie grew up together in Canada and moved to the USA to enroll in PhD programs at prestigious universities. For various reasons, Marie left her program and instead chose to work as a stripper. The author, at first troubled and yet fascinated by her friend's decision, follows Marie's journey ...

  9. A reconfiguration of the sex trade

    DEFF Research Database (Denmark)

    Elmes, Jocelyn; Skovdal, Morten; Nhongo, Kundai

    2017-01-01

    Understanding the dynamic nature of sex work is important for explaining the course of HIV epidemics. While health and development interventions targeting sex workers may alter the dynamics of the sex trade in particular localities, little has been done to explore how large-scale social and struc......Understanding the dynamic nature of sex work is important for explaining the course of HIV epidemics. While health and development interventions targeting sex workers may alter the dynamics of the sex trade in particular localities, little has been done to explore how large-scale social...... and structural changes, such as economic recessions–outside of the bounds of organizational intervention–may reconfigure social norms and attitudes with regards to sex work. Zimbabwe’s economic collapse in 2009, following a period (2000–2009) of economic decline, within a declining HIV epidemic, provides...... implications for their health and well-being. Transcripts were thematically analyzed. The analysis revealed how changing economic conditions, combined with an increased awareness and fear of HIV–changing norms and local attitudes toward sex work–had altered the demand for commercial sex. In response, sex work...

  10. Sex and the development of Alzheimer's disease.

    Science.gov (United States)

    Pike, Christian J

    2017-01-02

    Men and women exhibit differences in the development and progression of Alzheimer's disease (AD). The factors underlying the sex differences in AD are not well understood. This Review emphasizes the contributions of sex steroid hormones to the relationship between sex and AD. In women, events that decrease lifetime exposure to estrogens are generally associated with increased AD risk, whereas estrogen-based hormone therapy administered near the time of menopause may reduce AD risk. In men, estrogens do not exhibit age-related reduction and are not significantly associated with AD risk. Rather, normal age-related depletions of testosterone in plasma and brain predict enhanced vulnerability to AD. Both estrogens and androgens exert numerous protective actions in the adult brain that increase neural functioning and resilience as well as specifically attenuating multiple aspects of AD-related neuropathology. Aging diminishes the activational effects of sex hormones in sex-specific manners, which is hypothesized to contribute to the relationship between aging and AD. Sex steroid hormones may also drive sex differences in AD through their organizational effects during developmental sexual differentiation of the brain. Specifically, sex hormone actions during early development may confer inherent vulnerability of the female brain to development of AD in advanced age. The combined effects of organizational and activational effects of sex steroids yield distinct sex differences in AD pathogenesis, a significant variable that must be more rigorously considered in future research. © 2016 Wiley Periodicals, Inc.

  11. Making sense of sex tourism through the accounts of sex tourists : a Foucauldian discourse analysis of sex tourists' online communication

    OpenAIRE

    Søntvedt, Mari Sofie Grimstad

    2009-01-01

    This thesis explores the perspective of the male sex tourist by studying posts on a ‘sex travel guide’ web page. The study is placed within qualitative social psychology, and makes use of Foucauldian discourse analysis in a naturalistic setting. Thus, it is framed within social constructionist and poststructuralist epistemological frameworks. The aims of the study are to analyze the discursive resources the sex tourists draw upon in their posts, to explore how they construct the phenomenon of...

  12. Human sexuality and sex steroids.

    Science.gov (United States)

    Wróbel, Beata; Karasek, Michał

    2008-02-01

    Studies on human sexuality are considered to be extremely difficult. Moreover, their results appear often unclear and contradictory. Sexuality is perceived as the identity, feelings and behavior associated with sex. Different assumptions concerning its mechanisms are made by researchers in the field of neuroendocrinology, endocrinology and psychology, and their tests' results help to describe human sexuality. Since the second half of the 20th century efforts of describing sexuality have been made, but they are still imperfect. There are no current research methods which allow for separation of sexual functions or sex-related behavior in a human, and for their description. It should be remembered, however, that the very awareness of taking part in such examination can have meaningful impact on the tests' results. What is more, the patient's emotional state can also alter the results. In this paper, current results on sexual steroids' place in forming human sexuality and its role in an adult human being life are presented. The cognition of the complete role of testosterone, estradiol and progesterone in forming human sexuality is considered to be the challenge for researchers in the following years.

  13. Sex differences and stress across the lifespan

    Science.gov (United States)

    Bale, Tracy L; Epperson, C Neill

    2015-01-01

    Sex differences in stress responses can be found at all stages of life and are related to both the organizational and activational effects of gonadal hormones and to genes on the sex chromosomes. As stress dysregulation is the most common feature across neuropsychiatric diseases, sex differences in how these pathways develop and mature may predict sex-specific periods of vulnerability to disruption and increased disease risk or resilience across the lifespan. The aging brain is also at risk to the effects of stress, where the rapid decline of gonadal hormones in women combined with cellular aging processes promote sex biases in stress dysregulation. In this Review, we discuss potential underlying mechanisms driving sex differences in stress responses and their relevance to disease. Although stress is involved in a much broader range of diseases than neuropsychiatric ones, we highlight here this area and its examples across the lifespan. PMID:26404716

  14. PRENATAL SEX DETERMINATION: Issues and Concern

    Directory of Open Access Journals (Sweden)

    Deshpande JD

    2009-03-01

    Full Text Available A vast amount of knowledge and voluminous literature is available on sex discrimination in India over the last twenty years. Moreover, detailed statistics about sex ratio from various sources exist.Understanding the rationale behind prenatal sex determination is no doubt key to deciphering the dynamics of sex ratio in India. Present article is an attempt to review the main dimensions of the recentsex-ratio degradation in India: its origin, its mechanisms and social characteristics, its implications in the long run and its major causes. Analysis also points to the positive linkage between abnormal sex ratio and better socio-economic status and literacy. Child Sex ratio is not lowest in poor tribal districts or other backward areas, but in prosperous Western Maharashtra and other economically empowered districts. It is essential to raise awareness and seek attitudinal and behavior changes to tackle the problem.

  15. Sex-Biased Parent-Offspring Conflict

    OpenAIRE

    Redondo, T.; Gomendio, Montserrat; Medina, Rosario

    1992-01-01

    In species showing sexual dimorphism, parents may obtain different fitness returns per unit of parental expenditure from sons and daughters. Under these circumstances, parents are expected to invest extra resources in offspring of the most profitable sex. However, it is unclear whether sex-biased expenditure is the result of selection acting on parents, their offspring, or both. Current parent-offspring conflict theory is used to investigate whether sex biases in parental expenditure should b...

  16. Sex determination in forensic odontology: A review.

    Science.gov (United States)

    Ramakrishnan, K; Sharma, Subramanya; Sreeja, C; Pratima, D Bhavani; Aesha, I; Vijayabanu, B

    2015-08-01

    Forensic odontology is the application of dental principles to legal issues. Sex determination is a subdivision of forensic odontology and it is very important especially when information relating to the deceased is unavailable. Sex determination becomes the first priority in the process of identification of a person by a forensic investigator in the case of mishaps, chemical and nuclear bomb explosions, natural disasters crime investigations, and ethnic studies. This article reviews upon the various methods used in sex determination.

  17. Sex determination in forensic odontology: A review

    Science.gov (United States)

    Ramakrishnan, K.; Sharma, Subramanya; Sreeja, C.; Pratima, D. Bhavani; Aesha, I.; Vijayabanu, B.

    2015-01-01

    Forensic odontology is the application of dental principles to legal issues. Sex determination is a subdivision of forensic odontology and it is very important especially when information relating to the deceased is unavailable. Sex determination becomes the first priority in the process of identification of a person by a forensic investigator in the case of mishaps, chemical and nuclear bomb explosions, natural disasters crime investigations, and ethnic studies. This article reviews upon the various methods used in sex determination. PMID:26538886

  18. Same-Sex and Different-Sex Cohabiting Couple Relationship Stability.

    Science.gov (United States)

    Manning, Wendy D; Brown, Susan L; Stykes, J Bart

    2016-08-01

    Relationship stability is a key indicator of well-being, but most U.S.-based research has been limited to different-sex couples. The 2008 panel of the Survey of Income and Program Participation (SIPP) provides an untapped data resource to analyze relationship stability of same-sex cohabiting, different-sex cohabiting, and different-sex married couples (n = 5,701). The advantages of the SIPP data include the recent, nationally representative, and longitudinal data collection; a large sample of same-sex cohabitors; respondent and partner socioeconomic characteristics; and identification of a state-level indicator of a policy stating that marriage is between one man and one woman (i.e., DOMA). We tested competing hypotheses about the stability of same-sex versus different-sex cohabiting couples that were guided by incomplete institutionalization, minority stress, relationship investments, and couple homogamy perspectives (predicting that same-sex couples would be less stable) as well as economic resources (predicting that same-sex couples would be more stable). In fact, neither expectation was supported: results indicated that same-sex cohabiting couples typically experience levels of stability that are similar to those of different-sex cohabiting couples. We also found evidence of contextual effects: living in a state with a constitutional ban against same-sex marriage was significantly associated with higher levels of instability for same- and different-sex cohabiting couples. The level of stability in both same-sex and different-sex cohabiting couples is not on par with that of different-sex married couples. The findings contribute to a growing literature on health and well-being of same-sex couples and provide a broader understanding of family life.

  19. Same-Sex and Different-Sex Cohabiting Couple Relationship Stability

    Science.gov (United States)

    Manning, Wendy; Brown, Susan; Stykes, Bart

    2016-01-01

    Relationship stability is a key indicator of well-being, but most U.S.-based research has been limited to different-sex couples. The 2008 panel of the Survey of Income and Program Participation (SIPP) provides an untapped data resource to analyze relationship stability of same-sex cohabiting, different-sex cohabiting, and different-sex married couples (n = 5,701). The advantages of the SIPP data include the recent, nationally representative, and longitudinal data collection; a large sample of same-sex cohabitors; respondent and partner socioeconomic characteristics; and identification of a state-level indicator of a policy stating that marriage is between one man and one woman (i.e., DOMA). We tested competing hypotheses about the stability of same-sex versus different-sex cohabiting couples that were guided by incomplete institutionalization, minority stress, relationship investments, and couple homogamy perspectives (predicting that same-sex couples would be less stable) as well as economic resources (predicting that same-sex couples would be more stable). In fact, neither expectation was supported: results indicated that same-sex cohabiting couples typically experience levels of stability that are similar to those of different-sex cohabiting couples. We also found evidence of contextual effects: living in a state with a constitutional ban against same-sex marriage was significantly associated with higher levels of instability for same- and different-sex cohabiting couples. The level of stability in both same-sex and different-sex cohabiting couples is not on par with that of different-sex married couples. The findings contribute to a growing literature on health and well-being of same-sex couples and provide a broader understanding of family life. PMID:27383844

  20. Interactive Effects of Culture and Sex Hormones on Sex Role Orientation

    Directory of Open Access Journals (Sweden)

    Belinda ePletzer

    2015-07-01

    Full Text Available Sex role orientation, i.e. a person’s masculinity or femininity, influences cognitive and emotional performance, like biological sex. While it is now widely accepted that sex differences are modulated by the hormonal status of female participants (menstrual cycle, hormonal contraceptive use, the question, whether hormonal status and sex hormones also modulate participants sex role orientation has hardly been addressed previously. The present study assessed sex role orientation and hormonal status as well as sex hormone levels in three samples of participants from two different cultures (Northern American, Middle European. Menstrual cycle phase did not affect participant’s masculinity or femininity, but had a significant impact on reference group. While women in their follicular phase (low levels of female sex hormones determined their masculinity and femininity in reference to men, women in their luteal phase (high levels of female sex hormones determined their masculinity and femininity in reference to women. Hormonal contraceptive users rated themselves as significantly more feminine and less masculine than naturally cycling women. Furthermore, the impact of biological sex on the factorial structure of sex role orientation as well as the relationship of estrogen to masculinity/femininity was modulated by culture. We conclude that culture and sex hormones interactively affect sex role orientation and hormonal status of participants should be controlled for when assessing masculinity and/or femininity.

  1. Interactive effects of culture and sex hormones on the sex role self-concept.

    Science.gov (United States)

    Pletzer, Belinda; Petasis, Ourania; Ortner, Tuulia M; Cahill, Larry

    2015-01-01

    Sex role orientation, i.e., a person's masculinity or femininity, influences cognitive and emotional performance, like biological sex. While it is now widely accepted that sex differences are modulated by the hormonal status of female participants (menstrual cycle, hormonal contraceptive use), the question, whether hormonal status and sex hormones also modulate participants sex role orientation has hardly been addressed previously. The present study assessed sex role orientation and hormonal status as well as sex hormone levels in three samples of participants from two different cultures (Northern American, Middle European). Menstrual cycle phase did not affect participant's masculinity or femininity, but had a significant impact on reference group. While women in their follicular phase (low levels of female sex hormones) determined their masculinity and femininity in reference to men, women in their luteal phase (high levels of female sex hormones) determined their masculinity and femininity in reference to women. Hormonal contraceptive users rated themselves as significantly more feminine and less masculine than naturally cycling women. Furthermore, the impact of biological sex on the factorial structure of sex role orientation as well as the relationship of estrogen to masculinity/femininity was modulated by culture. We conclude that culture and sex hormones interactively affect sex role orientation and hormonal status of participants should be controlled for when assessing masculinity and/or femininity.

  2. Sex-biased eicosanoid biology: Impact for sex differences in inflammation and consequences for pharmacotherapy.

    Science.gov (United States)

    Pace, Simona; Sautebin, Lidia; Werz, Oliver

    2017-06-22

    The incidence, severity and progression of autoimmune diseases (e.g. scleroderma, multiple sclerosis, rheumatoid arthritis) and certain inflammatory diseases (e.g. asthma) are sex-biased where these pathologies dominate in women. However, other immune disorders such as sepsis, post-surgery infections and gout display higher incidence and severity in men. The molecular and cellular basis underlying this sex dimorphism remains incompletely elucidated but may provide important insights for sex-specific pharmacotherapy. Nevertheless, the sex as a variable in biochemical and preclinical research on inflammation is often neglected. Thus, respective animal studies are routinely performed with males, and experiments with isolated cells rarely report the sex of the donor. However, sex differences on the cellular level do exist, in particular related to inflammatory processes that prompt for sex-specific appreciation of inflammation research. For instance, the biosynthesis of pro-inflammatory eicosanoids is sex-biased where leukotriene (LT) formation is under control of testosterone that regulates the subcellular localization of the key enzyme 5-lipoxygenase, with possible implications for gender-tailored pharmacotherapy of LT-related disorders (i.e. asthma). Moreover, prostaglandin (PG) production is sex-biased, and sex-dependent efficacy of aspirin was evident in several clinical trials. Here, we highlight the sex bias in eicosanoid biology possibly underlying the obvious sex disparities in inflammation, stimulating scientists to take sex into account when studying the pathophysiology and pharmacotherapy of inflammatory diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Patpong, entre sexe et commerce.

    Directory of Open Access Journals (Sweden)

    Sébastien Roux

    2010-03-01

    Full Text Available Le tourisme dit « sexuel » est aujourd’hui décrié comme une forme de tourisme international immoral, un dysfonctionnement grave de la mondialisation appelant une réaction politique contre « l’exploitation sexuelle » dont seraient victimes des millions de femmes et d’enfants. Pourtant, derrière l’apparente évidence du « tourisme sexuel » comme expression de sens commun, rares sont les enquêtes qui explicitent la réalité concrète des échanges prostitutionnels. En adoptant une démarche ethnographique, l’article décrit le fonctionnement de Patpong, un quartier rouge de Bangkok dédié à une clientèle internationale. Par la description des offres disponibles, des revenus générés, des codes et des pratiques, la complexité de l’espace réapparaît. Il s’agit de donner à voir la réalité des échanges pour interroger l’articulation entre commerce et sexualité. L’analyse ethnographique du tourisme sexuel permet ainsi de souligner la diversité des pratiques et de rappeler que les formes les plus visibles — et les plus commentées — d’échanges prostitutionnels éclipsent trop souvent une pluralité d’expériences qui participe pourtant au succès de ces ruelles mondialement connues. So-called sex tourism is condemned as an immoral form of international tourism, a serious failure of globalization requiring political action against the “sexual exploitation” suffered by millions of women and children. Yet behind the common and seemingly evident understanding of “sexual tourism,” few studies have focused on the actual reality of such relations. Based on an ethnographic study, this article presents the structure of Patpong, a red-light district of Bangkok dedicated to international tourism. First, the article aims to briefly present the historical development of Patpong. This peculiar space is intrinsically linked to sex tourism, as these world-renowned streets expanded since the mid-60s to

  4. Female Sex Offenders: Public Awareness and Attributions.

    Science.gov (United States)

    Cain, Calli M; Anderson, Amy L

    2016-09-16

    Traditional gender roles, sex scripts, and the way female sex offenders are portrayed in the media may lead to misconceptions about who can commit sexual offenses. Sexual crimes by women may go unnoticed or unreported if there is a general lack of awareness that females commit these crimes. Data from the 2012 Nebraska Annual Social Indicators Survey were used to determine whether the public perceives women as capable sex offenders and the perceived causes of female sex offending. The traditional focus on male sex offenders by researchers, media, and politicians, in addition to gender stereotypes, introduces the possibility of group differences (e.g., between men and women) in perceptions of female sex offenders. Consequently, two secondary analyses were conducted that tested for group differences in both the public's perception of whether females can commit sex offenses and the explanations selected for why females sexually offend. The findings suggest that the public does perceive women as capable sex offenders, although there were group differences in the causal attributions for female sex offending.

  5. Economic analysis of same-sex marriage.

    Science.gov (United States)

    Portelli, Christopher J

    2004-01-01

    This article applies the neoclassical microeconomic analysis of marriage as developed by Nobel laureate economist Gary Becker to same-sex marriage. The objective is to demonstrate that the economic analysis of marriage supports allowing same-sex marriage, and that same-sex marriages would strengthen the incentive to marry, increase the efficiency of marriage markets, provide for more children to be raised in two-parent optimum environments, and benefit states economically overall. The article concludes with an overview of the economic impact of same-sex marriages on states based on the analysis, data and fiscal information currently available from researchers and economists in the field.

  6. Evolutionary stability of sex chromosomes in snakes

    Science.gov (United States)

    Rovatsos, Michail; Vukić, Jasna; Lymberakis, Petros; Kratochvíl, Lukáš

    2015-01-01

    Amniote vertebrates possess various mechanisms of sex determination, but their variability is not equally distributed. The large evolutionary stability of sex chromosomes in viviparous mammals and birds was believed to be connected with their endothermy. However, some ectotherm lineages seem to be comparably conserved in sex determination, but previously there was a lack of molecular evidence to confirm this. Here, we document a stability of sex chromosomes in advanced snakes based on the testing of Z-specificity of genes using quantitative PCR (qPCR) across 37 snake species (our qPCR technique is suitable for molecular sexing in potentially all advanced snakes). We discovered that at least part of sex chromosomes is homologous across all families of caenophidian snakes (Acrochordidae, Xenodermatidae, Pareatidae, Viperidae, Homalopsidae, Colubridae, Elapidae and Lamprophiidae). The emergence of differentiated sex chromosomes can be dated back to about 60 Ma and preceded the extensive diversification of advanced snakes, the group with more than 3000 species. The Z-specific genes of caenophidian snakes are (pseudo)autosomal in the members of the snake families Pythonidae, Xenopeltidae, Boidae, Erycidae and Sanziniidae, as well as in outgroups with differentiated sex chromosomes such as monitor lizards, iguanas and chameleons. Along with iguanas, advanced snakes are therefore another example of ectothermic amniotes with a long-term stability of sex chromosomes comparable with endotherms. PMID:26702042

  7. Evolutionary stability of sex chromosomes in snakes.

    Science.gov (United States)

    Rovatsos, Michail; Vukić, Jasna; Lymberakis, Petros; Kratochvíl, Lukáš

    2015-12-22

    Amniote vertebrates possess various mechanisms of sex determination, but their variability is not equally distributed. The large evolutionary stability of sex chromosomes in viviparous mammals and birds was believed to be connected with their endothermy. However, some ectotherm lineages seem to be comparably conserved in sex determination, but previously there was a lack of molecular evidence to confirm this. Here, we document a stability of sex chromosomes in advanced snakes based on the testing of Z-specificity of genes using quantitative PCR (qPCR) across 37 snake species (our qPCR technique is suitable for molecular sexing in potentially all advanced snakes). We discovered that at least part of sex chromosomes is homologous across all families of caenophidian snakes (Acrochordidae, Xenodermatidae, Pareatidae, Viperidae, Homalopsidae, Colubridae, Elapidae and Lamprophiidae). The emergence of differentiated sex chromosomes can be dated back to about 60 Ma and preceded the extensive diversification of advanced snakes, the group with more than 3000 species. The Z-specific genes of caenophidian snakes are (pseudo)autosomal in the members of the snake families Pythonidae, Xenopeltidae, Boidae, Erycidae and Sanziniidae, as well as in outgroups with differentiated sex chromosomes such as monitor lizards, iguanas and chameleons. Along with iguanas, advanced snakes are therefore another example of ectothermic amniotes with a long-term stability of sex chromosomes comparable with endotherms.

  8. Romance tourism or female sex tourism?

    Science.gov (United States)

    Bauer, Irmgard L

    2014-01-01

    Love, sex and the female traveller: romance tourism or female sex tourism? The phenomenon of women travelling in search of relationships with local men in developing countries has been studied for the last 20 years. However, it appears little known in travel medicine. Relevant literature was found through PubMed, Science Direct, ProQuest and Google Scholar. The reference lists of selected articles identified further sources. Historical records of women travellers to far-away countries abound. Then, as now, women not only searched for the erotic 'other' but made romance and sex the purpose of their trip. Today, increasing numbers of women travel to destinations in developing countries where sex with local men is the main attraction. This pastime raises concerns not only for the women themselves but for the local men involved as well as their sex partners and the local communities. Although more research is necessary, comparing the criteria that describe men travelling for sex and relationships and women travelling for sex and relationships appears to suggest that there is very little difference between the two, regardless of what the pursuit is called. Women looking for sex with local men are sex tourists, too. Recognition of this fact needs to influence the pre and post travel care of female travellers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Anal sex, vaginal sex and HIV risk among female sex workers in Papua New Guinea.

    Science.gov (United States)

    Kelly-Hanku, Angela; Rawstorne, Patrick; Kupul, Martha; Worth, Heather; Shih, Patti; Man, Wing Young Nicola

    2014-03-01

    Female sex workers (FSW) are considered one of the key affected populations in Papua New Guinea at risk of acquiring HIV. An integrated bio-behavioral survey of sex workers in Port Moresby was conducted to determine the nature and extent of this risk. About half (51.1 %) of the 411 FSW who reported having any sexual intercourse with clients had engaged in both anal and vaginal intercourse with clients in the last 6 months. In spite of having poorer HIV knowledge (OR95 % CI = 0.14-0.34), FSW who had anal intercourse with clients were significantly more likely to have used a condom at the last vaginal intercourse with a client (OR95 % CI = 1.04-2.87). Similarly, FSW who had anal intercourse with regular and casual partners were significantly more likely to have used a condom at the last vaginal intercourse. Those who engaged in both anal and vaginal intercourse with clients had similar condom use for both vaginal and anal intercourse, with the majority (78.1 %) using a condom at the last occasion for both vaginal and anal intercourse. These FSW may have different risk and protective factors that affect their use of condom during sexual intercourse. Further research is needed to investigate this difference between those who practice anal intercourse and those who do not in order to provide evidence for better programming.

  10. Vocabulary, Grammar, Sex, and Aging.

    Science.gov (United States)

    Moscoso Del Prado Martín, Fermín

    2017-05-01

    Understanding the changes in our language abilities along the lifespan is a crucial step for understanding the aging process both in normal and in abnormal circumstances. Besides controlled experimental tasks, it is equally crucial to investigate language in unconstrained conversation. I present an information-theoretical analysis of a corpus of dyadic conversations investigating how the richness of the vocabulary, the word-internal structure (inflectional morphology), and the syntax of the utterances evolves as a function of the speaker's age and sex. Although vocabulary diversity increases throughout the lifetime, grammatical diversities follow a different pattern, which also differs between women and men. Women use increasingly diverse syntactic structures at least up to their late fifties, and they do not deteriorate in terms of fluency through their lifespan. However, from age 45 onward, men exhibit a decrease in the diversity of the syntactic structures they use, coupled with an increased number of speech disfluencies. Copyright © 2016 Cognitive Science Society, Inc.

  11. Beyond the 'safe sex' propaganda.

    Science.gov (United States)

    Hadzic, Maja; Khajehei, Marjan

    2010-01-01

    In this paper, we discuss sexual relationships among teenagers, the related issues, and suggest addressing the issues through effective education programs for both teenagers and their parents. We also discuss the main issues resulting from initiation of sexual relationship during adolescence such as unwanted pregnancy, maternal mortality, abortion, sexually transmitted diseases and damaged mental health. In addition, we highlight the lack of adequate sex education in teenagers and emphasize on the negative influence of TV programs and the harmful effects of dysfunctional families. Moreover, this article proposes equipping teenagers with knowledge that will help them understand not only physical but also emotional, social, and mental dynamics of sexual relationships. We believe that this approach would intervene much earlier in their life, help teenagers make healthy decision and minimize negative consequences of their personal choices.

  12. Sex Differences in Tibiocalcaneal Kinematics

    Directory of Open Access Journals (Sweden)

    Sinclair Jonathan

    2014-08-01

    Full Text Available Purpose. Female runners typically suffer more from chronic running injuries than age-matched males, although the exact biome-chanical mechanisms behind the increased susceptibility of female runners are unknown. This study aimed to compare sex differences in tibiocalcaneal kinematics during the stance phase of running. Methods. Twenty male and twenty female participants ran at 4.0 m · s–1. Tibiocalcaneal kinematics were measured using an eight-camera motion analysis system and compared using independent samples t tests. Results. Peak eversion and tibial internal rotation angles were shown to be significantly greater in female runners. Conclusions. based on these observations, it was determined that female runners may be at increased risk from chronic injury development in relation to excessive tibiocalcaneal motions in the coronal and transverse planes.

  13. BIOLOGICAL SEX, SEX-ROLE ORIENTATION, MASCULINE SEX-ROLE STRESS, DISSIMULATION AND SELF-REPORTED FEARS

    NARCIS (Netherlands)

    ARRINDELL, WA; KOLK, AM; PICKERSGILL, MJ; HAGEMAN, WJJM

    1993-01-01

    Given meta-analytic findings showing females to be generally more fearful than males on multi-dimensional self-report measures of fear, an empirical attempt was made to examine whether this outcome could be explained by psychological factors such as sex role orientation and masculine sex role stress

  14. BIOLOGICAL SEX, SEX-ROLE ORIENTATION, MASCULINE SEX-ROLE STRESS, DISSIMULATION AND SELF-REPORTED FEARS

    NARCIS (Netherlands)

    ARRINDELL, WA; KOLK, AM; PICKERSGILL, MJ; HAGEMAN, WJJM

    1993-01-01

    Given meta-analytic findings showing females to be generally more fearful than males on multi-dimensional self-report measures of fear, an empirical attempt was made to examine whether this outcome could be explained by psychological factors such as sex role orientation and masculine sex role

  15. Television Sex Roles in the 1980s: Do Viewers' Sex and Sex Role Orientation Change the Picture?

    Science.gov (United States)

    Dambrot, Faye H.; And Others

    1988-01-01

    Investigates the viewer perceptions of female and male television characters as a result of viewer sex and sex role orientation, based on the responses of 677 young adults to the Personal Attributes Questionnaire (PAQ). Viewer gender had an impact on the rating of female characters. (FMW)

  16. Sex hormones adjust "sex-specific" reactive and diurnal cortisol profiles.

    Science.gov (United States)

    Juster, Robert-Paul; Raymond, Catherine; Desrochers, Alexandra Bisson; Bourdon, Olivier; Durand, Nadia; Wan, Nathalie; Pruessner, Jens C; Lupien, Sonia J

    2016-01-01

    Sex differences in stress hormone functions are presumed to depend on sex hormones. And yet, surprisingly few psychoneuroendocrine studies actually assess within-sex variations of testosterone, estradiol, and progesterone when investigating sex-specific activities of the hypothalamic-pituitary-adrenal axis. In this methodological study of 204 healthy adults (60 men), we assessed whether cortisol profiles would differ between the sexes when unadjusted or adjusted for basal sex hormones among both sexes. Reactive cortisol was sampled using 6 saliva samples measured every 10-min as part of the Trier Social Stress Test that generally activates cortisol among men more than women. Diurnal cortisol was sampled over two days at (1) awakening, (2) 30-min thereafter, (3) 1400 h, (4) 1600 h, and (5) bedtime. Sex hormones were collected at baseline before the psychosocial stressor and on two occasions during diurnal cortisol assessment. Repeated-measures analysis of covariance controlled for key covariates in analyses unadjusted or adjusted for sex hormones. Results revealed that men had higher reactive cortisol than women in unadjusted analysis, but this sex difference was attenuated when adjusting for sex hormones. While diurnal cortisol showed no sex differences in unadjusted models, adjusting for sex hormones revealed that women have higher morning cortisol. Correlations using area under the curve formulae revealed intriguing sex-specific associations with progesterone in men and testosterone in women that we propose have implications for social and affective neuroscience. In summary, our results reveal that adjusting for sex hormones alters "sex-specific" reactive and diurnal cortisol profiles.

  17. Molecular sex differences in human serum.

    Directory of Open Access Journals (Sweden)

    Jordan M Ramsey

    Full Text Available BACKGROUND: Sex is an important factor in the prevalence, incidence, progression, and response to treatment of many medical conditions, including autoimmune and cardiovascular diseases and psychiatric conditions. Identification of molecular differences between typical males and females can provide a valuable basis for exploring conditions differentially affected by sex. METHODOLOGY/PRINCIPAL FINDINGS: Using multiplexed immunoassays, we analyzed 174 serum molecules in 9 independent cohorts of typical individuals, comprising 196 males and 196 females. Sex differences in analyte levels were quantified using a meta-analysis approach and put into biological context using k-means to generate clusters of analytes with distinct biological functions. Natural sex differences were established in these analyte groups and these were applied to illustrate sexually dimorphic analyte expression in a cohort of 22 males and 22 females with Asperger syndrome. Reproducible sex differences were found in the levels of 77 analytes in serum of typical controls, and these comprised clusters of molecules enriched with distinct biological functions. Analytes involved in fatty acid oxidation/hormone regulation, immune cell growth and activation, and cell death were found at higher levels in females, and analytes involved in immune cell chemotaxis and other indistinct functions were higher in males. Comparison of these naturally occurring sex differences against a cohort of people with Asperger syndrome indicated that a cluster of analytes that had functions related to fatty acid oxidation/hormone regulation was associated with sex and the occurrence of this condition. CONCLUSIONS/SIGNIFICANCE: Sex-specific molecular differences were detected in serum of typical controls and these were reproducible across independent cohorts. This study extends current knowledge of sex differences in biological functions involved in metabolism and immune function. Deviations from typical

  18. Assortative mating among Dutch married and cohabiting same-sex and different-sex couples

    NARCIS (Netherlands)

    Verbakel, E.; Kalmijn, M.

    2014-01-01

    The authors compared male and female same-sex and different-sex couples in the Netherlands with respect to age and educational homogamy. Because many same-sex couples in the Netherlands are married, differences between married and cohabiting couples were analyzed for all 3 groups. Analyses of data f

  19. A demographic model for sex ratio evolution and the effects of sex-biased offspring costs

    NARCIS (Netherlands)

    Shyu, E.; Caswell, H.

    The evolution of the primary sex ratio, the proportion of male births in an individual's offspring production strategy, is a frequency-dependent process that selects against the more common sex. Because reproduction is shaped by the entire life cycle, sex ratio theory would benefit from explicitly

  20. Conflict over condition-dependent sex allocation can lead to mixed sex-determination systems

    NARCIS (Netherlands)

    Kuijper, Bram; Pen, Ido

    2014-01-01

    Theory suggests that genetic conflicts drive turnovers between sex-determining mechanisms, yet these studies only apply to cases where sex allocation is independent of environment or condition. Here, we model parent-offspring conflict in the presence of condition-dependent sex allocation, where the

  1. Sex ratio selection and multi-factorial sex determination in the housefly : A dynamic model

    NARCIS (Netherlands)

    Kozielska, M.A.; Pen, I.R.; Beukeboom, L.W.; Weissing, F.J.

    Sex determining (SD) mechanisms are highly variable between different taxonomic groups and appear to change relatively quickly during evolution. Sex ratio selection could be a dominant force causing such changes. We investigate theoretically the effect of sex ratio selection on the dynamics of a

  2. Biological Sex, Sex-Role, and Self-Actualization of College Students.

    Science.gov (United States)

    Guyot, Gary W.; Vollemaere, Erik

    Self-actualization, which involves the ultimate development of one's abilities regardless of external influences, is the basis for many personality theories. To assess the relationship between biological sex, sex role, and self-actualization, the Bem Sex Role Inventory (BSRI) and the Personal Orientation Inventory (POI) were administered to 129…

  3. Offspring sex ratio bias and sex related characteristics of eggs in chicken

    NARCIS (Netherlands)

    Aslam, M.A.

    2014-01-01

    Understanding the factors influencing sex of egg and sex ratio in laying chicken may lead to finding potential solutions for the problem of killing of day old male chicks, which is the current practice in breeding of laying hens. In studies described in this thesis, it was investigated if the sex of

  4. "Dangerous Presumptions": How Single-Sex Schooling Reifies False Notions of Sex, Gender, and Sexuality

    Science.gov (United States)

    Jackson, Janna

    2010-01-01

    Due to the recent changes in federal regulations about gender equity in education in the USA, some policy makers have resurrected single-sex public education. Because single-sex schooling ignores the complexity of sex, gender, and sexuality, it sets up a "separate but equal" system that is anything but. Discounting the ways in which gender is…

  5. Offspring sex ratio bias and sex related characteristics of eggs in chicken

    NARCIS (Netherlands)

    Aslam, M.A.

    2014-01-01

    Understanding the factors influencing sex of egg and sex ratio in laying chicken may lead to finding potential solutions for the problem of killing of day old male chicks, which is the current practice in breeding of laying hens. In studies described in this thesis, it was investigated if the sex of

  6. Conflict over condition-dependent sex allocation can lead to mixed sex-determination systems

    NARCIS (Netherlands)

    Kuijper, Bram; Pen, Ido

    2014-01-01

    Theory suggests that genetic conflicts drive turnovers between sex-determining mechanisms, yet these studies only apply to cases where sex allocation is independent of environment or condition. Here, we model parent-offspring conflict in the presence of condition-dependent sex allocation, where the

  7. Sex ratio selection and multi-factorial sex determination in the housefly : A dynamic model

    NARCIS (Netherlands)

    Kozielska, M.A.; Pen, I.R.; Beukeboom, L.W.; Weissing, F.J.

    2006-01-01

    Sex determining (SD) mechanisms are highly variable between different taxonomic groups and appear to change relatively quickly during evolution. Sex ratio selection could be a dominant force causing such changes. We investigate theoretically the effect of sex ratio selection on the dynamics of a mul

  8. "Dangerous Presumptions": How Single-Sex Schooling Reifies False Notions of Sex, Gender, and Sexuality

    Science.gov (United States)

    Jackson, Janna

    2010-01-01

    Due to the recent changes in federal regulations about gender equity in education in the USA, some policy makers have resurrected single-sex public education. Because single-sex schooling ignores the complexity of sex, gender, and sexuality, it sets up a "separate but equal" system that is anything but. Discounting the ways in which gender is…

  9. Effects of Physical Attractiveness, Sex and Sex-Role on Trait Attributions.

    Science.gov (United States)

    Major, Brenda; Deaux, Kay

    This research investigates how androgynous men and women are evaluated relative to those who are sex-typed or sex reversed, and also investigates the joint effects of attractiveness and sex-role upon such evaluation. Two studies with replicable results were conducted. In each, approximately 185 male and 185 female undergraduates were asked to rate…

  10. Sex Education: The Principle and the Principal.

    Science.gov (United States)

    Wayne, Joseph E.

    1981-01-01

    The school principal is in a propitious position to offer leadership in developing a sex education program. His position of leadership and respect can facilitate the development of a Citizens Advisory Committee which, in turn, can ensure cooperation and leadership in setting the goals for developing a sex education program. (Author/CM)

  11. Children in Same-Sex Marriages

    Science.gov (United States)

    Solodnikov, V. V.; Chkanikova, A. M.

    2009-01-01

    In Russia, sociologists do not have reliable statistical data as to the number of same-sex unions and the number of children being brought up in these families, and non-Russian studies on the topic are flawed and misleading. Russians are said to be antagonistic to the idea of children being raised in same-sex households. People are concerned over…

  12. Microbial manipulation of host sex determination

    NARCIS (Netherlands)

    Beukeboom, Leo W.

    A recent study in the lepidopteran Ostrinia scapulalis shows that endosymbionts can actively manipulate the sex determination mechanism of their host. Wolbachia bacteria alter the sex-specific splicing of the doublesex master switch gene. In ZZ males of this female heterogametic system, the female

  13. Sex reduces genetic variation: a multidisciplinary review.

    Science.gov (United States)

    Gorelick, Root; Heng, Henry H Q

    2011-04-01

    For over a century, the paradigm has been that sex invariably increases genetic variation, despite many renowned biologists asserting that sex decreases most genetic variation. Sex is usually perceived as the source of additive genetic variance that drives eukaryotic evolution vis-à-vis adaptation and Fisher's fundamental theorem. However, evidence for sex decreasing genetic variation appears in ecology, paleontology, population genetics, and cancer biology. The common thread among many of these disciplines is that sex acts like a coarse filter, weeding out major changes, such as chromosomal rearrangements (that are almost always deleterious), but letting minor variation, such as changes at the nucleotide or gene level (that are often neutral), flow through the sexual sieve. Sex acts as a constraint on genomic and epigenetic variation, thereby limiting adaptive evolution. The diverse reasons for sex reducing genetic variation (especially at the genome level) and slowing down evolution may provide a sufficient benefit to offset the famed costs of sex. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.

  14. Lickona Promotes False Claims about Sex Education.

    Science.gov (United States)

    Bennetta, William J.

    1994-01-01

    In articles on sex and character education in the November 1993 "Educational Leadership," Thomas Lickona parrots slogans and fake history and statistics contrived by the Religious Right. Lickona blames Darwin's evolution theory for variable morality and repeats fabricated success claims for Teen-Aid and Sex Respect, right-wing programs funded…

  15. Sex Differences in Cardiovascular Drug Response

    NARCIS (Netherlands)

    E.M. Rodenburg (Eline)

    2012-01-01

    textabstractIn the early sixties, a prominent professor in Clinical Pharmacology at the University College in London, D.R. Laurence, stated: “There are no clinically important sex differences in drug action, except, of course, to sex steroid hormones, but the subject is poorly documented. Women are

  16. Sex Role Ideology, Marital Status, and Happiness.

    Science.gov (United States)

    Lueptow, Lloyd B.; And Others

    1989-01-01

    Analyzed General Social Survey data to determine if women's sex role ideology may be negatively related to marital happiness and stability. Found women with nontraditional gender values less happy and more likely to be separated or divorced. Results suggest that modern sex role ideology is negatively related to marital success for women.…

  17. Sex Parties: Female Teen Sexual Experimentation

    Science.gov (United States)

    Toscano, Sharyl Eve

    2006-01-01

    Adolescent participants in a study aimed at exploring the nature and characteristics of girls' dating relationships revealed the phenomenon of sex parties. These teens defined a "sex party" as an opportunity to engage in sexual contact outside of typical dating relationships. Sexual activity could involve actual intercourse, but usually involved…

  18. Sex Stereotyping in Children's Toy Advertisements.

    Science.gov (United States)

    Schwartz, Lori A.; Markham, William T.

    1985-01-01

    Describes a survey of toy catalogs and packages, which focused on stereotypes in depictions of children playing with toys. Reports that toys that were previously rated by students as strongly or moderately sex-typed were generally shown with a child of the "appropriate" sex. (KH)

  19. Achieving Sex Equity via Vocational Education.

    Science.gov (United States)

    Goetsch, David L.; Gulledge, Earl N.

    1981-01-01

    Reviews the women's rights movement and discusses the evolution of society's attitudes toward women. Discusses the goals and methods of Okaloosa-Walton Junior College Sex Equity Plan, a vocational education program for achieving sex equity. Highlights five major components: education, student recruitment, self-paced, self-directed instruction, job…

  20. The Gestalt Experiment in Sex Therapy.

    Science.gov (United States)

    Mosher, Donald L.

    1979-01-01

    The Gestalt experiment is applicable to sex therapy. Familiarity with modes and methods of experimenting permits the therapist's creativity to emerge. Applications of sexual metaphors and sex dysfunction as a nightmare are presented, using methods drawn from Gestalt dream work. The use of Gestalt experiments are illustrated in a client-therapist…

  1. Dating Preferences in Sex Stereotypic Men.

    Science.gov (United States)

    Smith, Christine A.

    Although research suggest a general preference by men for attractive partners, attractiveness may be more important for some men than for others. This study was conducted to investigate the role of men's sex stereotypic attitudes on their dating preferences. It was hypothesized that the level of sex stereotyping would correlate with the level…

  2. A Preliminary Typology of Young Sex Offenders.

    Science.gov (United States)

    Langstrom, Niklas; Grann, Martin; Lindblad, Frank

    2000-01-01

    Uses data concerning all young sex offenders (N=56) to construct and validate an introductory young sex offender typology based solely on offense characteristics. A 5-cluster solution received optimal support from cluster analysis of 15 offense-related variables. Survival analysis revealed that the clusters differed with respect to sexual but not…

  3. Female meiotic sex chromosome inactivation in chicken

    NARCIS (Netherlands)

    S. Schoenmakers (Sam); E. Wassenaar (Evelyne); J.W. Hoogerbrugge (Jos); J.S.E. Laven (Joop); J.A. Grootegoed (Anton); W.M. Baarends (Willy)

    2009-01-01

    textabstractDuring meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI) leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (Z

  4. Sex Differences in the Adolescent Brain

    Science.gov (United States)

    Lenroot, Rhoshel K.; Giedd, Jay N.

    2010-01-01

    Adolescence is a time of increased divergence between males and females in physical characteristics, behavior, and risk for psychopathology. Here we will review data regarding sex differences in brain structure and function during this period of the lifespan. The most consistent sex difference in brain morphometry is the 9-12% larger brain size…

  5. Microbial manipulation of host sex determination

    NARCIS (Netherlands)

    Beukeboom, Leo W.

    2012-01-01

    A recent study in the lepidopteran Ostrinia scapulalis shows that endosymbionts can actively manipulate the sex determination mechanism of their host. Wolbachia bacteria alter the sex-specific splicing of the doublesex master switch gene. In ZZ males of this female heterogametic system, the female i

  6. ZWY Sex Determination in Xenopus tropicalis

    Science.gov (United States)

    Most vertebrate species with described genetic sex determination are either male (XY) or female (ZW) heterogametic. To date, studies with Xenopus species indicate that members of this genus operate under a ZW sex determination system. We used two different approaches and demonst...

  7. Sex in Relation to Second Language Learning

    Institute of Scientific and Technical Information of China (English)

    柳丽

    2012-01-01

    This paper first reviews the research on sex by linguists, then analyzes sex differences in examinations, and put forward the concept of "sexual teaching" o Teachers should use all sorts of teaching activities to achieve the purpose of improving English communication ability.

  8. Oral sex, oral health and orogenital infections

    Directory of Open Access Journals (Sweden)

    Saini Rajiv

    2010-01-01

    Full Text Available Oral sex is commonly practiced by sexually active male-female and same-gender couples of various ages, including adolescents. The various type of oral sex practices are fellatio, cunnilingus and analingus. Oral sex is infrequently examined in research on adolescents; oral sex can transmit oral, respiratory, and genital pathogens. Oral health has a direct impact on the transmission of infection; a cut in your mouth, bleeding gums, lip sores or broken skin increases chances of infection. Although oral sex is considered a low risk activity, it is important to use protection and safer sex precautions. There are various methods of preventing infection during oral sex such as physical barriers, health and medical issues, ethical issues and oral hygiene and dental issues. The lesions or unhealthy periodontal status of oral cavity accelerates the phenomenon of transmission of infections into the circulation. Thus consequences of unhealthy or painful oral cavity are significant and oral health should be given paramount importance for the practice of oral sex.

  9. Sex Fair Grading in Physical Education.

    Science.gov (United States)

    Deutsch, Helga

    1984-01-01

    Sex fair performance evaluation has been a primary concern in physical education. A discussion of physiological differences between males and females shows how problems in developing fair evaluation plans arise. Suggestions for developing a sex fair grading plan and an example program adaptable to other settings are offered. (DF)

  10. Sex hormones and skeletal muscle weakness

    DEFF Research Database (Denmark)

    Sipilä, Sarianna; Narici, Marco; Kjaer, Michael

    2013-01-01

    Human ageing is accompanied with deterioration in endocrine functions the most notable and well characterized of which being the decrease in the production of sex hormones. Current research literature suggests that low sex hormone concentration may be among the key mechanism for sarcopenia and mu...

  11. Dangerous Liaisons: Substance Abuse and Sex.

    Science.gov (United States)

    Columbia Univ., New York, NY. National Center on Addiction and Substance Abuse.

    This report takes a comprehensive look at the connections between alcohol, drug use, and sex. Two national data sets on more than 34,000 teenagers and two sets on arrested and incarcerated sex offenders were analyzed. A review of the literature, interviews with experts, and an examination of programs aimed at prevention of abuse were included in…

  12. Sex differences in the HPA axis.

    Science.gov (United States)

    Goel, Nirupa; Workman, Joanna L; Lee, Tiffany T; Innala, Leyla; Viau, Victor

    2014-07-01

    The hypothalamic-pituitary-adrenal (HPA) axis is a major component of the systems that respond to stress, by coordinating the neuroendocrine and autonomic responses. Tightly controlled regulation of HPA responses is critical for maintaining mental and physical health, as hyper- and hypo-activity have been linked to disease states. A long history of research has revealed sex differences in numerous components of the HPA stress system and its responses, which may partially form the basis for sex disparities in disease development. Despite this, many studies use male subjects exclusively, while fewer reports involve females or provide direct sex comparisons. The purpose of this article is to present sex comparisons in the functional and molecular aspects of the HPA axis, through various phases of activity, including basal, acute stress, and chronic stress conditions. The HPA axis in females initiates more rapidly and produces a greater output of stress hormones. This review focuses on the interactions between the gonadal hormone system and the HPA axis as the key mediators of these sex differences, whereby androgens increase and estrogens decrease HPA activity in adulthood. In addition to the effects of gonadal hormones on the adult response, morphological impacts of hormone exposure during development are also involved in mediating sex differences. Additional systems impinging on the HPA axis that contribute to sex differences include the monoamine neurotransmitters norepinephrine and serotonin. Diverse signals originating from the brain and periphery are integrated to determine the level of HPA axis activity, and these signals are, in many cases, sex-specific.

  13. Cardiovascular sex differences influencing microvascular exchange

    Science.gov (United States)

    Huxley, Virginia H.; Wang, Jianjie

    2010-01-01

    The vital role of the cardiovascular (CV) system is maintenance of body functions via the matching of exchange to tissue metabolic demand. Sex-specific differences in the regulatory mechanisms of CV function and the metabolic requirements of men and women, respectively, have been identified and appreciated. This review focuses on sex differences of parameters influencing exchange at the point of union between blood and tissue, the microvasculature. Microvascular architecture, blood pressure (hydrostatic and oncotic), and vascular permeability, therefore, are discussed in the specific context of sex in health and disorders. It is notable that when sex differences exist, they are generally subtle but significant. In the aggregate, though, they can give rise to profoundly different phenotypes. The postulated mechanisms responsible for sex differences are attributed to genomics, epigenetics, and sex hormones. Depending on specific circumstances, the effect of the combined factors can range from insignificant to lethal. Identifying and understanding key signalling mechanisms bridging genomics/sex hormones and microvascular exchange properties within the scope of this review holds significant promise for sex-specific prevention and treatment of vascular barrier dysfunction. PMID:20495187

  14. Can Sex Education Delay Early Sexual Debut?

    Science.gov (United States)

    Erkut, Sumru; Grossman, Jennifer M.; Frye, Alice A.; Ceder, Ineke; Charmaraman, Linda; Tracy, Allison J.

    2013-01-01

    In this study, we examine whether a nine-lesson sex education intervention, "Get Real: Comprehensive Sex Education That Works," implemented in sixth grade, can reduce the number of adolescents who might otherwise become "early starters" of sexual activity (defined as heterosexual intercourse) by seventh grade. Participants were…

  15. Quick-Fix Sex: Pseudosexuality in Adolescents.

    Science.gov (United States)

    Hajcak, Frank; Garwood, Patricia

    1988-01-01

    Offers therapists, parents, and educators a model for understanding adolescent sexuality, focusing on how nonsexual needs drive sexual behavior and produce artificially high sex drive. Proposes that overwhelming intensity of adolescent sex drive is due to factors other than libido or biological phenomena. Advocates teaching teenagers what their…

  16. Sex Role Stereotypes Are Alive and Well.

    Science.gov (United States)

    Snodgrass, Sara E.

    Two studies, in late 1988 and early 1990, examined sex-role stereotypes held by northeastern liberal arts college students (N=719) and southern state university college students (N=145). The first study used the Personal Attributes Questionnaire (PAQ) and compared ratings of men and women with the traditional sex-roles represented by the PAQ in…

  17. SEX DETERMINATION FROM FEMORAL HEAD DIAMETERS IN ...

    African Journals Online (AJOL)

    hi-tech

    2000-03-01

    Mar 1, 2000 ... The IP of Malawian males was comparable to southwestern Nigerian males. ... version 6.08 and the T-tests were employed to find differences between the sexes ..... 6. Thieme, F.P. Sex in Negro skeleton. J. Forens.Med. 1957;.

  18. Sexual maldevelopment and sex reversal, chromosomal causes.

    Science.gov (United States)

    Magenis, R Ellen

    2006-01-01

    The SRY gene on the Y chromosome is the testis determining factor (TDF). It is therefore the initial male determining factor. However, phenotypic sex determination includes a cascade of genes located on autosomes as well as sex chromosomes. Aberrations of these genes may cause sexual maldevelopment or sex reversal. Abnormalities may include single gene mutations and gene loss or gain-changes may involve only sex organs or may be part of syndromes. These changes may also arise as chromosome abnormalities involving contiguous genes. Eight cases with chromosomal abnormalities involving different causative mechanisms are described herein. The most common cause is nondisjunction, including loss or gain of sex chromosomes. Less common causes are mispairing and crossing over in meiosis, chromosome breaks with repair, nonhomologous pairing due to low copy repeats and crossing over, and translocation (familial or de novo) with segregation. Cases include: [see: text].

  19. Acting parentally: an argument against sex selection.

    Science.gov (United States)

    McDougall, R

    2005-10-01

    The Human Fertilisation and Embryology Authority's (HFEA) recent restrictive recommendations on sex selection have highlighted the need for consideration of the plausibility of ethical arguments against sex selection. In this paper, the author suggests a parental virtues approach to some questions of reproductive ethics (including sex selection) as a superior alternative to an exclusively harm focused approach such as the procreative liberty framework. The author formulates a virtue ethics argument against sex selection based on the idea that acceptance is a character trait of the good parent. It is concluded that, because the argument presented posits a wrong in the sex selecting agent's action that is not a harm, the argument could not function as a justification of the HFEA's restrictive position in light of their explicit commitment to procreative liberty; it does, however, suggest that ethical approaches focused exclusively on harm fail to capture all the relevant moral considerations and thus that we should look beyond such approaches.

  20. [Sex workers: limited access to healthcare].

    Science.gov (United States)

    Gloor, E; Meystre-Agustoni, G; Ansermet-Pagot, A; Vaucher, P; Durieux-Paillard, S; Bodenmann, P; Cavassini, M

    2011-06-29

    Sex workers constitute a heterogeneous group possessing a combination of vulnerability factors such as geographical instability, forced migration, substance addiction and lack of legal residence permit. Access to healthcare for sex workers depends on the laws governing the sex market and on migration policies in force in the host country. In this article, we review different European health strategies established for sex workers, and present preliminary results of a pilot study conducted among 50 sex workers working on the streets in Lausanne. The results are worrying: 56% have no health insurance, 96% are migrants and 66% hold no legal residence permit. These data should motivate public health departments towards improving access to healthcare for this vulnerable population.

  1. Effects of leaders' and evaluators' sex on sex-role stereotyping of charismatic leaders.

    Science.gov (United States)

    Grinnell, James P

    2002-12-01

    This study extends research on sex and leadership by examining the relation between evaluators' and leaders' sex and the sex-role stereotyping of charismatic leaders. A total of 219 students (110 men and 109 women) from a large northeastern university rated charismatic leaders depicted in vignettes using the revised Bem Sex-Role Inventory: overall, the leaders were rated higher on masculinity than femininity. Analysis by sex of evaluator and leader showed masculinity was higher in all cases except when male charismatic leaders were evaluated by women. In this case, the results support an androgynous view, i.e., high on both masculinity and femininity.

  2. Environment and sex determination in farmed fish.

    Science.gov (United States)

    Baroiller, J F; D'Cotta, H

    2001-12-01

    A plasticity of gonadal sex differentiation was reported in the 1930s following exogenous steroid treatments in fish, but demonstration that environmental factors (temperature, pH, density and social interactions) could influence the sex ratio in gonochoristic species has been relatively recent. In fish, as in reptiles and amphibians displaying environmental sex determination, the main environmental factor influencing sex seems to be temperature (TSD=Temperature Sex Determination). In most thermosensitive species (some Atherinids, Poecilids, Cichlids: tilapias, goldfish, a Siluriform, a flatfishellipsis) male to female ratio increases with temperature and/or ovarian differentiation is induced by low temperatures. Conversely, in some rare species (Dicentrarchus labrax, Ictalurus punctatus), high temperatures may produce female-biased sex ratios and/or low temperatures promote male-biased sex ratios. In the hirame Paralichthys olivaceus, both high and low temperatures induce monosex male populations while intermediate temperatures yield a 1:1 sex ratio (U-shape curve). Fish show particularities in their TSD patterns since mono-sex populations are generally not produced at extreme temperatures, suggesting the existence of strong temperature/genotype interactions. In reptiles, amphibians and fish displaying TSD, temperature treatments must be applied at a critical sensitive period, relatively similar to the hormone sensitive period. In gonochoristic fish, steroid hormones with estrogens in females and 11-oxygenated androgens in males, are probably key physiological steps in the regulation of gonadal sex differentiation. Cytochrome P450-aromatase, enzyme catalysing conversion of androgens to estrogens, seems to be a critical enzyme for ovarian differentiation. Molecular mechanisms of thermosensitivity have been addressed in two species tilapia Oreochromis niloticus and the hirame, where aromatase gene expression is down-regulated by masculinizing temperature treatments

  3. Why we should consider sex (and study sex differences) in addiction research.

    Science.gov (United States)

    Sanchis-Segura, Carla; Becker, Jill B

    2016-09-01

    Among mammals, every cell has a biological sex, and the sex of an individual pervades its body and brain. In this review, we describe the processes through which mammals become phenotypically male or female by organizational and activational influences of genes and hormones throughout development. We emphasized that the molecular and cellular changes triggered by sex chromosomes and steroid hormones may generate sex differences in overt physiological functions and behavior, but they may alternatively promote end-point convergences between males and females. Clinical and pre-clinical evidences suggest that sex and gender differences modulate drug consumption as well as of the transition towards drug-promoted pathological states such as dependence and addiction. Additionally, sex differences in drug pharmacokinetics and pharmacodynamics will also influence dependence and addiction as well as side effects of drugs. These effects will further interact with socially gendered factors to result in sex differences in the access to, engagement in and efficacy of any therapeutic attempt. Finally, we maintain that 'sex sameness' is as important as 'sex differences' when building a complete understanding of biology for both males and females and provide a framework with which to classify and guide investigation into the mechanisms mediating sex differences and sex sameness.

  4. Sex choice in plants: facultative adjustment of the sex ratio in the perennial herb Begonia gracilis.

    Science.gov (United States)

    López, S; Domínguez, C A

    2003-11-01

    Sex allocation theory predicts that reproducing individuals will increase their fitness by facultatively adjusting their relative investment towards the rarer sex in response to population shifts in operational sex ratio (OSR). The evolution of facultative manipulation of sex ratio depends on the ability of the parents to track the conditions favouring skewed sex allocation and on the mechanism controlling sex allocation. In animals, which have well-developed sensorial mechanisms, facultative adjustment of sex ratios has been demonstrated on many occasions. In this paper, we show that plants have mechanisms that allow them to evaluate the population OSR. We simulated three different conditions of population OSR by manipulating the amount of pollen received by the female flowers of a monoecious herb, and examined the effect of this treatment on the allocation to male vs. female flowers. A shortage of pollen on the stigmas resulted in a more male-skewed sex allocation, whereas plants that experienced a relatively pollen rich environment tended to produce a more female-skewed sex allocation pattern. Our results for Begonia gracilis demonstrate that the individuals of this species are able to respond to the levels of pollination intensity experienced by their female flowers and adjust their patterns of sex allocation in accordance to the expectations of sex allocation theory.

  5. Sex-Specific Selection and Sex-Biased Gene Expression in Humans and Flies.

    Science.gov (United States)

    Cheng, Changde; Kirkpatrick, Mark

    2016-09-01

    Sexual dimorphism results from sex-biased gene expression, which evolves when selection acts differently on males and females. While there is an intimate connection between sex-biased gene expression and sex-specific selection, few empirical studies have studied this relationship directly. Here we compare the two on a genome-wide scale in humans and flies. We find a distinctive "Twin Peaks" pattern in humans that relates the strength of sex-specific selection, quantified by genetic divergence between male and female adults at autosomal loci, to the degree of sex-biased expression. Genes with intermediate degrees of sex-biased expression show evidence of ongoing sex-specific selection, while genes with either little or completely sex-biased expression do not. This pattern apparently results from differential viability selection in males and females acting in the current generation. The Twin Peaks pattern is also found in Drosophila using a different measure of sex-specific selection acting on fertility. We develop a simple model that successfully recapitulates the Twin Peaks. Our results suggest that many genes with intermediate sex-biased expression experience ongoing sex-specific selection in humans and flies.

  6. Sex-Specific Selection and Sex-Biased Gene Expression in Humans and Flies.

    Directory of Open Access Journals (Sweden)

    Changde Cheng

    2016-09-01

    Full Text Available Sexual dimorphism results from sex-biased gene expression, which evolves when selection acts differently on males and females. While there is an intimate connection between sex-biased gene expression and sex-specific selection, few empirical studies have studied this relationship directly. Here we compare the two on a genome-wide scale in humans and flies. We find a distinctive "Twin Peaks" pattern in humans that relates the strength of sex-specific selection, quantified by genetic divergence between male and female adults at autosomal loci, to the degree of sex-biased expression. Genes with intermediate degrees of sex-biased expression show evidence of ongoing sex-specific selection, while genes with either little or completely sex-biased expression do not. This pattern apparently results from differential viability selection in males and females acting in the current generation. The Twin Peaks pattern is also found in Drosophila using a different measure of sex-specific selection acting on fertility. We develop a simple model that successfully recapitulates the Twin Peaks. Our results suggest that many genes with intermediate sex-biased expression experience ongoing sex-specific selection in humans and flies.

  7. How sex work becomes an option: Experiences of female sex workers in Kerman, Iran.

    Science.gov (United States)

    Karamouzian, Mohammad; Foroozanfar, Zohre; Ahmadi, Azal; Haghdoost, Ali Akbar; Vogel, Joanna; Zolala, Farzaneh

    2016-01-01

    Sex work is rarely an occupation of choice for Iranian women and is often described as a last resort. While several factors play a role in creating an environment where individuals become involved in sex work, female sex workers' experiences regarding entry into sex work in Iran are poorly understood. In this qualitative study, a convenience sample of 24 participants was recruited from a drop-in centre for vulnerable women in Kerman, Iran. Through in-depth interviews, participants were asked about their personal lived experiences of initiating sex work. Grounded theory was used to analyse findings from this research. We learned that major factors impacting on women's initiation into sex work circulated around their vulnerability and chronic poverty. Participants continued to sell sex due to their limited opportunities, drug dependence and financial needs. Improving sex workers' economic status could be a vital intervention in providing vulnerable women with options other than sex work. Female sex workers should be provided with government support and educational programmes delivered through special centres. Despite the illegal status of their work, sex workers' needs should be recognised across all aspects of policy and legislation.

  8. Criminal profiles of violent juvenile sex and violent juvenile non sex offenders: an explorative longitudinal study.

    Science.gov (United States)

    van Wijk, Anton Ph; Mali, Bas R F; Bullens, Ruud A R; Vermeiren, Robert R

    2007-10-01

    Few studies have longitudinally investigated the criminal profiles of violent juvenile sex and violent juvenile non-sex offenders. To make up for this lack, this study used police records of juveniles to determine the nature of the criminal profiles of violent sex offenders (n = 226) and violent non-sex offenders (n = 4,130). All offenders committed their first offense in 1996 and were followed for 7 years. Results showed that violent sex offenders and violent non-sex offenders cannot be considered a homogeneous group because of different background characteristics and criminal profiles. Sex and violent offenses often constitute a small part of a broader criminal pattern. Further research is necessary to reveal in more detail the developmental and criminological patterns of violent and sexual delinquency. Treatment and intervention programs may benefit from this.

  9. Too close for comfort? Registered sex offender spatial clustering and recidivistic sex crime arrest rates.

    Science.gov (United States)

    Socia, Kelly M

    2013-12-01

    This study examined whether three measures of the spatial distribution of registered sex offenders (RSOs) in September 2010 were associated with differences in county-level rates of recidivistic sex crime arrests over the following year in 52 upstate New York counties. Results indicate that RSO clustering was positively associated with modest increases of recidivistic sex crime arrest rates, but results were significant only for adult victim sex crimes and only for certain types of RSO clustering. Under no circumstances, however, was increased RSO clustering associated with decreased rates of recidivistic sex crime arrests. The results of this study, combined with the limited prior research, suggest that RSO clustering has only a limited association with recidivistic sex crime arrest rates. This implies that housing policies such as residence restrictions may be useful in mitigating risk from some types of recidivistic sex crimes only to the extent that they result in more equitable distributions of RSOs within a county.

  10. Wild sex in zebrafish: loss of the natural sex determinant in domesticated strains.

    Science.gov (United States)

    Wilson, Catherine A; High, Samantha K; McCluskey, Braedan M; Amores, Angel; Yan, Yi-lin; Titus, Tom A; Anderson, Jennifer L; Batzel, Peter; Carvan, Michael J; Schartl, Manfred; Postlethwait, John H

    2014-11-01

    Sex determination can be robustly genetic, strongly environmental, or genetic subject to environmental perturbation. The genetic basis of sex determination is unknown for zebrafish (Danio rerio), a model for development and human health. We used RAD-tag population genomics to identify sex-linked polymorphisms. After verifying this "RAD-sex" method on medaka (Oryzias latipes), we studied two domesticated zebrafish strains (AB and TU), two natural laboratory strains (WIK and EKW), and two recent isolates from nature (NA and CB). All four natural strains had a single sex-linked region at the right tip of chromosome 4, enabling sex genotyping by PCR. Genotypes for the single nucleotide polymorphism (SNP) with the strongest statistical association to sex suggested that wild zebrafish have WZ/ZZ sex chromosomes. In natural strains, "male genotypes" became males and some "female genotypes" also became males, suggesting that the environment or genetic background can cause female-to-male sex reversal. Surprisingly, TU and AB lacked detectable sex-linked loci. Phylogenomics rooted on D. nigrofasciatus verified that all strains are monophyletic. Because AB and TU branched as a monophyletic clade, we could not rule out shared loss of the wild sex locus in a common ancestor despite their independent domestication. Mitochondrial DNA sequences showed that investigated strains represent only one of the three identified zebrafish haplogroups. Results suggest that zebrafish in nature possess a WZ/ZZ sex-determination mechanism with a major determinant lying near the right telomere of chromosome 4 that was modified during domestication. Strains providing the zebrafish reference genome lack key components of the natural sex-determination system but may have evolved variant sex-determining mechanisms during two decades in laboratory culture.

  11. Exploring dynamics of anal sex among female sex workers in Andhra Pradesh

    Directory of Open Access Journals (Sweden)

    Saroj Tucker

    2012-01-01

    Full Text Available Objective: The anal sex among heterosexual couples is on the rise as reported in many scientific studies. Considering that unprotected anal sex has higher risk of human immunodeficiency virus (HIV transmission than the vaginal sex, we undertook a study to understand the anal sex practices among Female Sex Workers (FSW. Materials and Methods: The study was conducted among FSW attending 11 randomly selected sexually transmitted infection (STI clinics in Bill and Melinda Gates supported targeted interventions in Andhra Pradesh. A structured questionnaire was administered to the 555 FSW attending these clinics by project clinic counselors. Informed consent was obtained from all the study participants. Results: Engaging in anal sex was self reported by 22% of sex workers, though demand from clients was reported to be much higher (40%. The reasons for anal sex practices included more money (61%, clout/influence of the client (45%, risk of losing client (27%, and forced sex (1.2%. Factors associated with anal sex were higher number of clients, higher duration of sex work, higher income, and older age group. Associated risks perceived by FSW were bleeding and injury to anal canal (98% while only 28% associated it with higher HIV transmission risk. Reported Condom and lubricant use was about 88% and 39% respectively. Conclusion: The study shows that there is frequent anal sex, inconsistent condom and infrequent lubricant usage, economic and physical coercion, and low awareness of STI/HIV transmission risk among FSW, which have serious implications for HIV prevention programmes. There is a need to focus on anal sex education and use of lubricants along with condoms during anal sex in FSW-targeted interventions in AP.

  12. Do manatees talk during sex?

    Science.gov (United States)

    Self-Sullivan, Caryn; Gilbertson, Tamra; Evans, William E.

    2002-05-01

    On January 13, 1999, manatee vocalizations were recorded during a mating herd event in the Orange River, Florida. Although copulation could not be observed, multiple males were observed with exposed penises. During one 25 min sample (1300-1325 h), over 400 manatee signals were recorded. In March 2000, each signal was captured and digitized from the analog tape using a Marantz PMD 501, Ashly equalizer (gain=0, filter=0), MAC 8100, and Canary 1.2.1. In general, signals were 100-200 ms in length, highly harmonic (up to 8 harmonics ranging from 1 to 16 kHz), with little or no frequency modulation. Intervals between signals ranged from less than 1 s to 14 s (mean = 3 s), indicating that manatees do indeed talk (a lot) during sex. Noise from two passing boats was also recorded during the sample period. One abnormally low-frequency signal (0.4 kHz) was recorded during one boat pass. This apparent manatee vocalization could be seen and heard below the boat noise frequency band.

  13. Sex steroids and glucose metabolism

    Directory of Open Access Journals (Sweden)

    Carolyn A Allan

    2014-04-01

    Full Text Available Testosterone levels are lower in men with metabolic syndrome and type 2 diabetes mellitus (T2DM and also predict the onset of these adverse metabolic states. Body composition (body mass index, waist circumference is an important mediator of this relationship. Sex hormone binding globulin is also inversely associated with insulin resistance and T2DM but the data regarding estrogen are inconsistent. Clinical models of androgen deficiency including Klinefelter's syndrome and androgen deprivation therapy in the treatment of advanced prostate cancer confirm the association between androgens and glucose status. Experimental manipulation of the insulin/glucose milieu and suppression of endogenous testicular function suggests the relationship between androgens and insulin sensitivity is bidirectional. Androgen therapy in men without diabetes is not able to differentiate the effect on insulin resistance from that on fat mass, in particular visceral adiposity. Similarly, several small clinical studies have examined the efficacy of exogenous testosterone in men with T2DM, however, the role of androgens, independent of body composition, in modifying insulin resistance is uncertain.

  14. Novel sex cells and evidence for sex pheromones in diatoms.

    Science.gov (United States)

    Sato, Shinya; Beakes, Gordon; Idei, Masahiko; Nagumo, Tamotsu; Mann, David G

    2011-01-01

    Diatoms belong to the stramenopiles, one of the largest groups of eukaryotes, which are primarily characterized by a presence of an anterior flagellum with tubular mastigonemes and usually a second, smooth flagellum. Based on cell wall morphology, diatoms have historically been divided into centrics and pennates, of which only the former have flagella and only on the sperm. Molecular phylogenies show the pennates to have evolved from among the centrics. However, the timing of flagellum loss--whether before the evolution of the pennate lineage or after--is unknown, because sexual reproduction has been so little studied in the 'araphid' basal pennate lineages, to which Pseudostaurosira belongs. Sexual reproduction of an araphid pennate, Pseudostaurosira trainorii, was studied with light microscopy (including time lapse observations and immunofluorescence staining observed under confocal scanning laser microscopy) and SEM. We show that the species produces motile male gametes. Motility is mostly associated with the extrusion and retrieval of microtubule-based 'threads', which are structures hitherto unknown in stramenopiles, their number varying from one to three per cell. We also report experimental evidence for sex pheromones that reciprocally stimulate sexualization of compatible clones and orientate motility of the male gametes after an initial 'random walk'. The threads superficially resemble flagella, in that both are produced by male gametes and contain microtubules. However, one striking difference is that threads cannot beat or undulate and have no motility of their own, and they do not bear mastigonemes. Threads are sticky and catch and draw objects, including eggs. The motility conferred by the threads is probably crucial for sexual reproduction of P. trainorii, because this diatom is non-motile in its vegetative stage but obligately outbreeding. Our pheromone experiments are the first studies in which gametogenesis has been induced in diatoms by cell

  15. Novel sex cells and evidence for sex pheromones in diatoms.

    Directory of Open Access Journals (Sweden)

    Shinya Sato

    Full Text Available BACKGROUND: Diatoms belong to the stramenopiles, one of the largest groups of eukaryotes, which are primarily characterized by a presence of an anterior flagellum with tubular mastigonemes and usually a second, smooth flagellum. Based on cell wall morphology, diatoms have historically been divided into centrics and pennates, of which only the former have flagella and only on the sperm. Molecular phylogenies show the pennates to have evolved from among the centrics. However, the timing of flagellum loss--whether before the evolution of the pennate lineage or after--is unknown, because sexual reproduction has been so little studied in the 'araphid' basal pennate lineages, to which Pseudostaurosira belongs. METHODS/PRINCIPAL FINDING: Sexual reproduction of an araphid pennate, Pseudostaurosira trainorii, was studied with light microscopy (including time lapse observations and immunofluorescence staining observed under confocal scanning laser microscopy and SEM. We show that the species produces motile male gametes. Motility is mostly associated with the extrusion and retrieval of microtubule-based 'threads', which are structures hitherto unknown in stramenopiles, their number varying from one to three per cell. We also report experimental evidence for sex pheromones that reciprocally stimulate sexualization of compatible clones and orientate motility of the male gametes after an initial 'random walk'. CONCLUSIONS/SIGNIFICANCE: The threads superficially resemble flagella, in that both are produced by male gametes and contain microtubules. However, one striking difference is that threads cannot beat or undulate and have no motility of their own, and they do not bear mastigonemes. Threads are sticky and catch and draw objects, including eggs. The motility conferred by the threads is probably crucial for sexual reproduction of P. trainorii, because this diatom is non-motile in its vegetative stage but obligately outbreeding. Our pheromone experiments

  16. Sex Bias in Neuroscience and Biomedical Research

    Science.gov (United States)

    Beery, Annaliese K.; Zucker, Irving

    2010-01-01

    Female mammals have long been neglected in biomedical research. The NIH mandated enrollment of women in human clinical trials in 1993, but no similar initiatives exist to foster research on female animals. We reviewed sex bias in research on mammals in 10 biological fields for 2009 and their historical precedents. Male bias was evident in 8 disciplines and most prominent in neuroscience, with single-sex studies of male animals outnumbering those of females 5.5 to 1. In the past half-century, male bias in non-human studies has increased while declining in human studies. Studies of both sexes frequently fail to analyze results by sex. Underrepresentation of females in animal models of disease is also commonplace, and our understanding of female biology is compromised by these deficiencies. The majority of articles in several journals are conducted on rats and mice to the exclusion of other useful animal models. The belief that non-human female mammals are intrinsically more variable than males and too troublesome for routine inclusion in research protocols is without foundation. We recommend that when only one sex is studied, this should be indicated in article titles, and that funding agencies favor proposals that investigate both sexes and analyze data by sex. PMID:20620164

  17. Putting sex education in its place.

    Science.gov (United States)

    Cassell, C

    1981-04-01

    In order to help reduce fears and anxieties regarding the influence of sex education in a public school setting, school and community sexuality educators need to better articulate the difference between formal and structured sex education and non-formal, informal and incidental sex learning. Sex education is only 1 aspect of the sexual learning process. 2 main points have to be clarified for parents and the general public to set the stage for a new way to view the school and community involvement in the sexual learning process: the schools' sexuality education courses constitute only a small portion of the sexual learning process; and sexual learning is not an event for youth only, but a process spanning life. Sex education (the process) connotates an academic setting with a specific curricula taught by a trained instructor, but sexual learning relates to environmental, non-formal incidental learning from a multitude of sources. Studies indicate that teenagers receive about 90% of their contraceptive and sexuality informaation from peers and mass media and that these sources of information are becoming their preferred sources of sex education. What is needed is a way to address and improve the conditions of sexual learning in the community. As home is the ideal environment for primary and positive sexual learning, parents need support in their role as sex educators. Classroom sexuality education curricula in all school settings have a solid place in the process of sexual learning.

  18. The evolution of female sex pheromones

    Directory of Open Access Journals (Sweden)

    Ally R. HARARI, Hadass STEINITZ

    2013-08-01

    Full Text Available The role of female sex pheromones in natural selection, particularly as a means for species recognition to avoid the generation of hybrid offspring with low fitness, has been widely explored and is generally accepted by scholars. However, the significance of sex pheromones in shaping mate choice (sexual selection and in competition over breeding resources (social selection has been largely ignored. The effect of sexual selection on sex pheromones as a sexually dimorphic signaling trait has been discounted because the amount of pheromone released by females is typically minute, while the role of sex pheromones in competition over breeding resources (other than mates has not yet been considered. As a result of natural selection, variation in sex pheromones among females is expected to be low, and males are not expected to choose their mates among pheromone-releasing conspecific females. Sexual selection, on the other hand, should drive the increase in pheromone variance among females, and males are expected to choose females based on this variation. Moreover, social selection resulting from more general social interactions, for example competition among females for breeding sites and food, should also promote variance among female sex pheromones. Here, we review the current evidence for each of the three selection processes acting on sex pheromones of female moths as an advertising trait. We suggest that the three selection types are not mutually exclusive but rather act together to promote different fitness components in diverse ecological situations [Current Zoology 59 (4: 569–578, 2013].

  19. Sex Differences in Judgments of Social Desirability.

    Science.gov (United States)

    Paunonen, Sampo V

    2016-08-01

    This study evaluates sex differences in the perceived desirability of personality behaviors and beliefs. Men and women (N = 149, Mage  = 18.7) judged the social desirability scale values (SDSVs) of 150 personality statements as applied either to a male target or a female target. For comparison, some estimated SDSVs with no target sex specified. A separate sample of 537 respondents endorsed the 150 items via self-report. Raters showed a high consensus in their SDSV judgments within conditions (α = .86 to .90) and no sex-of-rater effects across conditions. Substantial sex-of-target effects (p desirable for one sex but not for the other. The behaviors seen as more (less) desirable when applied to men rather than to women were endorsed more (less) by men than by women in the respondent sample. Similar results were found when no target sex was specified for the SDSV ratings, presumably because judges evaluated the behaviors as applied to a target of their own sex. The present results have important implications for the measurement and reporting of SDSVs, the evaluation of substance versus style in self-reports, and the construction of desirability-reduced personality inventories. © 2015 Wiley Periodicals, Inc.

  20. Sex determination: insights from the silkworm

    Indian Academy of Sciences (India)

    Masataka G. Suzuki

    2010-09-01

    The sex-determining system differs considerably among organisms. Even among insect species, the genetic system for sex-determination is highly diversified. In Drosophila melanogaster, somatic sexual differentiation is regulated by a well characterized genetic hierarchy X : A > Sxl > tra/tra2 > dsx and fru. This cascade seems to control sex determination in all Drosophila species and is partially conserved in another dipteran species, Ceratitis capitata: Cctra/Cctra-2 > Ccdsx and Ccfru. However, in the silkworm, Bombyx mori, femaleness is determined by the presence of a dominant feminizing factor on the W chromosome. Moreover, no sex-specific regulatory Sxl homolog has been isolated from B. mori. Also, no tra homolog has yet been found in the Bombyx genome. Despite such differences, dsx homolog of B. mori (Bmdsx) is implicated in the sex determination. Bmdsx produces alternatively spliced mRNA isoforms that encode sex specific transcription factors as observed in dsx. While the female-specific splicing of dsx is activated by splicing activators, Tra and Tra2, the female splicing of Bmdsx represents the default mode. Instead, a splicing inhibitor, BmPSI is involved in the regulation of male-specific splicing of Bmdsx. Since BmPSI does not exhibit any sequence relationship to known SR proteins, such as Tra and Tra2, the regulatory mechanism of sex-specific alternative splicing of Bmdsx is distinct from that of dsx.

  1. Phenotypically flexible sex allocation in a simultaneous hermaphrodite

    NARCIS (Netherlands)

    Brauer, Verena S.; Schaerer, Lukas; Michiels, Nico K.

    2007-01-01

    Previous studies on sex allocation in simultaneous hermaphrodites have typically focused either on evolutionary or one-time, ontogenetic optimization of sex allocation, ignoring variation within an individual's lifetime. Here, we study whether hermaphrodites also possess facultative sex allocation,

  2. HIV prevention among female sex workers in Africa

    African Journals Online (AJOL)

    A. Scheibe, F. M. Drame, and K. Shannon

    2012-12-06

    Dec 6, 2012 ... UNAIDS' three pillar approach to HIV prevention and sex work we present an overview of current .... of HIV infection among sex workers compared to the general ... of sub-Saharan African countries, leaving sex workers with.

  3. Applications of sexed semen in cattle production.

    Science.gov (United States)

    Hohenboken, W D

    1999-12-01

    Sexed semen will contribute to increased profitability of dairy and beef cattle production in a variety of ways. It could be used to produce offspring of the desired sex from a particular mating to take advantage of differences in value of males and females for specific marketing purposes. Commercial dairy farmers, those who produce and market milk, could use sexed semen to produce replacement daughters from genetically superior cows and beef crossbred sons from the remainder of their cow population. To increase the rate of response to selection, seedstock dairy cattle breeders could produce bulls for progeny testing from a smaller number of elite dams by using sexed semen to ensure that all of them produced a son. Using sexed semen could then reduce the cost of progeny testing those bulls, because fewer matings would be necessary to produce any required number of daughters. Commercial beef cattle farmers, producing animals for eventual slaughter, could use sexed semen to capitalize on the higher value of male than female offspring for meat production. They could also use sexed semen to produce specialized, genetically superior replacement heifers from as small a proportion of the herd as possible. This would allow the remainder of the herd to produce male calves from bulls or breeds with superior genetic merit for growth, feed conversion efficiency, and carcass merit. Single-sex, bred-heifer systems, in which each female is sold for slaughter soon after weaning her replacement daughter, would be possible with the use of X-chromosome-sorted semen. Use of sexed semen would make terminal crossbreeding systems more efficient and sustainable in beef cattle. Fewer females would be required to produce specialized maternal crossbred daughters, and more could be devoted to producing highly efficient, terminal crossbred sons.

  4. Sex education vital for Chinese adolescents.

    Science.gov (United States)

    Zhang, Z

    1997-02-01

    This article summarizes findings from a survey conducted among adolescents in Beijing and Tianjin, China. Findings indicate that 89.3% of sex offenders were adolescents. Many high school students were engaged in premarital sexual relations, but lacked knowledge about sex and contraception. Premarital sex and sexually transmitted diseases are considered a social evil. The central government has direct jurisdiction in Tianjin and its population of 9 million. By 1989 there were 540,000, or 12% of total population, aged 12-16 years. A survey of 3231 junior middle school students aged 11-14 years revealed that 35% of girls did not know why menstruation occurred at a certain age. About 55% of boys did not know about erections. 35% considered an erect penis a part of normal physical development, but over 50% were confused. 30-50% of students who had reached menarche and sexual maturity found it difficult to find knowledgeable people. 50% received information from the mass media. 44% of girls learned from their mothers. 25% of boys and girls aged 11-12 years already had girlfriends and boyfriends. About 30% desired friends of the opposite sex and desired intimacy, love, and dependability among friends. It is argued that the backward notions of sex originated in a once feudal society that considered sex a taboo. Parents, teachers, and school authorities are resistant to introducing sex education; teachers are embarrassed by the subject matter. In Beijing about 4000 students aged 11-14 years were interviewed. These students had limited information on sex-related issues and misconceptions. Attitudes must be changed and teachers must be trained before adolescent health and sex education can be introduced into schools. The government can play a role in promoting programs for adolescents and coordinating the efforts of nongovernmental groups.

  5. One's sex, sleep, and posttraumatic stress disorder

    Directory of Open Access Journals (Sweden)

    Kobayashi Ihori

    2012-12-01

    Full Text Available Abstract Women are approximately twice as likely as men to develop posttraumatic stress disorder (PTSD after trauma exposure. Mechanisms underlying this difference are not well understood. Although sleep is recognized to have a critical role in PTSD and physical and psychological health more generally, research into the role of sleep in PTSD sex differences has been only recent. In this article, we review both animal and human studies relevant to sex differences in sleep and PTSD with an emphasis on the roles of sex hormones. Sleep impairment including insomnia, trauma-related nightmares, and rapid-eye-movement (REM sleep fragmentation has been observed in individuals with chronic and developing PTSD, suggesting that sleep impairment is a characteristic of PTSD and a risk factor for its development. Preliminary findings suggested sex specific patterns of sleep alterations in developing and established PTSD. Sleep maintenance impairment in the aftermath of trauma was observed in women who subsequently developed PTSD, and greater REM sleep fragmentation soon after trauma was associated with developing PTSD in both sexes. In chronic PTSD, reduced deep sleep has been found only in men, and impaired sleep initiation and maintenance with PTSD have been found in both sexes. A limited number of studies with small samples have shown that sex hormones and their fluctuations over the menstrual cycle influenced sleep as well as fear extinction, a process hypothesized to be critical to the pathogenesis of PTSD. To further elucidate the possible relationship between the sex specific patterns of PTSD-related sleep alterations and the sexually dimorphic risk for PTSD, future studies with larger samples should comprehensively examine effects of sex hormones and the menstrual cycle on sleep responses to trauma and the risk/resilience for PTSD utilizing various methodologies including fear conditioning and extinction paradigms and animal models.

  6. Dişhekimliği pratiğinde kullanılan mekanik aletlerin kalp pili ve takılabilir kardiyoverter/defibrilatör taşıyan hastalarda güvenilirliği

    Directory of Open Access Journals (Sweden)

    Mert Sanri

    2011-01-01

    hastaların sayısı gün geçtikçe artmaktadır. Bu hastaların çoğu aynı zamanda dental ofisleri de ziyaret eden yaşlı bireylerden oluşmaktadır. Diş hekimliği tedavilerinde kullanılmakta olan diş ve kök yüzeyi temizleme aletleri, kemik kesme amaçlı cerrahide kullanılan ultrasonik aletler, kanal boyu tespitinde kullanılan apeks bulucular, elektrikle pulpa canlılığı ölçücü cihazlar (vitalometre, pille çalışan ışın cihazları,  elektrokoterler gibi aletler, kalp pilleri ve TKD’ler ile etkileşimlere girebilecek potansiyel cihazlar olarak düşünülebilir. Bu makalede, diş hekimliği pratiğinde sıkça kullanılan bu mekanik aletlerin, kalp pili ve TKD taşıyan hastalar üzerindeki etkilerini inceleyen çalışmalar derlenmiştir.

    Anahtar Kelimeler: Kalp pili, defibrilatör,  elektromanyetik etkileşim, dental ekipman.

          ABSTRACT

          Pacemakers and implantable cardioverter-defibrillators (ICD are electronic devices that emit electrical signals. These devices are sensitive to the electronic signals around their enviroment. The number of patients carrying these devices is increasing day after day globally and in our country  Most of these patients  consist of old individuals, who also visit dental offices. Tooth and root surface cleaning devices, ultrasonic instruments used for bone cutting, apex

  7. Sex in America online: an exploration of sex, marital status, and sexual identity in internet sex seeking and its impacts.

    Science.gov (United States)

    Albright, Julie M

    2008-01-01

    This was an exploratory study of sex and relationship seeking on the Internet, based on a survey of 15,246 respondents in the United States Seventy-five percent of men and 41% of women had intentionally viewed or downloaded porn. Men and gays/lesbians were more likely to access porn or engage in other sex-seeking behaviors online compared with straights or women. A symmetrical relationship was revealed between men and women as a result of viewing pornography, with women reporting more negative consequences, including lowered body image, partner critical of their body, increased pressure to perform acts seen in pornographic films, and less actual sex, while men reported being more critical of their partners' body and less interested in actual sex. Married and divorced were more likely than singles to go online seeking a serious relationship. Only 2% of users met the threshold of compulsive use established by previous studies.

  8. Same-sex marriage and mental health.

    Science.gov (United States)

    Liangas, Georgios; Athanasou, James A

    2016-12-01

    It has been proposed that legislation for same-sex marriage has a positive mental health benefit. The purpose of this paper is to review and evaluate the empirical and conceptual links between same-sex marriage and mental health. There are substantive methodological issues in the four surveys and comparisons undertaken. Difficulties with the validity of the evidence are discussed. Conceptual difficulties in the arguments relating to victimisation as well as the psychology of marriage are highlighted. It was concluded that it is premature to make claims of causality vis-a-vis same-sex marriage legislation and mental health. © The Royal Australian and New Zealand College of Psychiatrists 2016.

  9. Sex ratios in natural populations of Drosophila pseudoobscura from Mexico

    OpenAIRE

    Salceda Victor M.; Arceo-Maldonado Carolina

    2012-01-01

    Most species show an equal proportion of individuals of both sexes. In diploid species sex ratio is determined by a genic balance between sex chromosomes. In Drosophila sex is determined by the ratio of X- chromosomes versus autosomes and in some species of the genus it is related to the presence of an inversion in the sex chromosome. The present work analyses the sex ratio in 27 natural populations of Drosophila pseudoobscura that inhabit Mexico. Female fl...

  10. Sex reversal in Betta splendens Regan with emphasis on the problem of sex determination.

    Science.gov (United States)

    Lowe, T P; Larkin, J R

    1975-01-01

    To gain insight into the sex-determining mechanism of the Siamese fighting fish, Betta splendens, sex-reversed individuals were bred and the ratios of the spawnings were examined. Sex-reversal of 245 females was undertaken by ovariectomizing them; of these, 104 became sex-reversed. Twenty-three of these latter fish were mated to normal females and eleven spawnings were raised to maturity. These spawnings resulted in all female broods or mixed broods. Were the male fish heterogametic, a view currently held by some authors, no males would be produced in these spawnings. Thus, male heterogamety was not substaintiated in this study. Contrary to other studies, the experimental sex reversal of females is not a rare event since nearly two-thirds of the fish that survived the surgery became sex-reversed. Gross dissection and histological observation of sex-reversed fish revealed a regenerated, unpaired duct which remained after the ovaries had been removed. The tissue of the regenerate was testicular and contained active spermatogenesis. Some alterative methods of sex determination which may apply to the Betta are examined. These include the possibility of two different sex-determining races, the effects of exogenous factors, and a polygenic system of sex determination.

  11. Sex Work Venue and Condom Use among Female Sex Workers in Senggigi, Indonesia

    Science.gov (United States)

    Safika, Iko; Levy, Judith A.; Johnson, Timothy P.

    2013-01-01

    This paper examines the structural influence of sex work venues on condom use among female sex workers in the Senggigi area of Lombok, Indonesia. A cross-sectional design employing ethnographic observation, structured interviews and hierarchical linear modeling was used to examine condom use among female sex workers who solicited clients at three types of sex work venues: freelance, brothels, and entertainment places (karaoke bars and massage parlours). The sample consisted of 115 women “nested” within 16 sex work venues drawn from the three venue types. Rate (39%) of condom use varied across sex work venues. Perceived management style, HIV/AIDS-related policies, and risk-reduction services differed by venue, but this variation did not explain differences in condom use. At the individual level, higher condom use was associated with female sex workers having ever been married. At the client level, condoms were more likely to be used with foreign rather than domestic/local Indonesian clients. Low rates of condom use among Indonesian female sex workers during commercial sex suggests the need for increased HIV prevention efforts that acknowledge sex worker characteristics and relationships with clients that place them at risk. Future research into the effects of social context on HIV risk should also be considered. PMID:23472595

  12. Sex-different response in growth traits to resource heterogeneity explains male-biased sex ratio

    Science.gov (United States)

    Matsushita, Michinari; Takao, Mikako; Makita, Akifumi

    2016-08-01

    In dioecious plants, differences in growth traits between sexes in a response to micro-environmental heterogeneity may affect sex ratio bias and spatial distributions. Here, we examined sex ratios, stem growth traits and spatial distribution patterns in the dioecious clonal shrub Aucuba japonica var. borealis, in stands with varying light intensities. We found that male stems were significantly more decumbent (lower height/length ratio) but female stems were upright (higher height/length ratio). Moreover, we found sex-different response in stem density (no. of stems per unit area) along a light intensity gradient; in males the stem density increased with increases in canopy openness, but not in females. The higher sensitivity of males in increasing stem density to light intensity correlated with male-biased sex ratio; fine-scale sex ratio was strongly male-biased as canopy openness increased. There were also differences between sexes in spatial distributions of stems. Spatial segregation of sexes and male patches occupying larger areas than female patches might result from vigorous growth of males under well-lit environments. In summary, females and males showed different growth responses to environmental variation, and this seemed to be one of possible causes for the sex-differential spatial distributions and locally biased sex ratios.

  13. Stable Cretaceous sex chromosomes enable molecular sexing in softshell turtles (Testudines: Trionychidae)

    Science.gov (United States)

    Rovatsos, Michail; Praschag, Peter; Fritz, Uwe; Kratochvšl, Lukáš

    2017-01-01

    Turtles demonstrate variability in sex determination ranging from environmental sex determination (ESD) to highly differentiated sex chromosomes. However, the evolutionary dynamics of sex determining systems in this group is not well known. Differentiated ZZ/ZW sex chromosomes were identified in two species of the softshell turtles (Trionychidae) from the subfamily Trionychinae and Z-specific genes were identified in a single species. We tested Z-specificity of a subset of these genes by quantitative PCR comparing copy gene numbers in male and female genomes in 10 species covering the phylogenetic diversity of trionychids. We demonstrated that differentiated ZZ/ZW sex chromosomes are conserved across the whole family and that they were already present in the common ancestor of the extant trionychids. As the sister lineage, Carettochelys insculpta, possess ESD, we can date the origin of the sex chromosomes in trionychids between 200 Mya (split of Trionychidae and Carettochelyidae) and 120 Mya (basal splitting of the recent trionychids). The results support the evolutionary stability of differentiated sex chromosomes in some lineages of ectothermic vertebrates. Moreover, our approach determining sex-linkage of protein coding genes can be used as a reliable technique of molecular sexing across trionychids useful for effective breeding strategy in conservation projects of endangered species. PMID:28186115

  14. "Bareback" pornography consumption and safe-sex intentions of men having sex with men.

    Science.gov (United States)

    Jonas, Kai J; Hawk, Skyler T; Vastenburg, Danny; de Groot, Peter

    2014-05-01

    Men having sex with men (MSM) commonly consume "bareback" pornography, which includes scenes of unprotected anal intercourse. Prior research on human imitative behavior suggests that these media might counteract efforts to promote safe-sex behaviors. To date, no studies have demonstrated a causal link between bareback pornography consumption and reduced safe-sex intentions. Study 1 utilized a correlational design conducted as an online survey. Study 2 was set in an actual MSM sex club, using a 2 × 2 mixed-factorial design to compare type of pornography (unprotected vs. protected anal intercourse) and age of actors (younger vs. older). As the main dependent variable in both studies, participants self-reported their inclinations toward unprotected versus protected intercourse, using a 100-point sliding scale (1 = unprotected, 100 = protected). In Study 1, more attention to unprotected sex acts on actual DVD film covers predicted lower safe-sex intentions, as compared to other elements of the film cover. In Study 2, safe-sex intentions after viewing unprotected-sex films were lower than after viewing protected-sex films. The results provide novel and ecologically valid evidence that "bareback" pornography consumption impacts viewer's inclinations toward sexual risk-taking by lowering their intentions to use protected sex measures. Suggestions are given as to how these findings can be utilized for purposes of intervention and prevention of STI and HIV infections.

  15. Sex work venue and condom use among female sex workers in Senggigi, Indonesia.

    Science.gov (United States)

    Safika, Iko; Levy, Judith A; Johnson, Timothy P

    2013-01-01

    This paper examines the structural influence of sex work venues on condom use among female sex workers in the Senggigi area of Lombok, Indonesia. A cross-sectional design employing ethnographic observation, structured interviews and hierarchical linear modelling was used to examine condom use among female sex workers who solicited clients at three types of sex work venues: (1) freelance locations, (2) brothels and (3) entertainment places (karaoke bars and massage parlours). The sample consisted of 115 women 'nested' within 16 sex work venues drawn from the three venue types. Rate (39%) of condom use varied across sex work venues. Perceived management style, HIV/AIDS-related policies and risk-reduction services differed by venue, but this variation did not explain differences in condom use. At the individual level, higher condom use was associated with female sex workers having ever been married. At the client level, condoms were more likely to be used with foreign rather than domestic/local Indonesian clients. Low rates of condom use among Indonesian female sex workers during commercial sex suggests the need for increased HIV-prevention efforts that acknowledge sex worker characteristics and relationships with clients that place them at risk. Future research into the effects of social context on HIV risk should also be considered.

  16. Associations between internet sex seeking and STI associated risk behaviours among men who have sex with men

    National Research Council Canada - National Science Library

    Mettey, A; Crosby, R; DiClemente, R J; Holtgrave, D R

    2003-01-01

    .... Differences in critical behaviours (unprotected anal sex and number of partners) were not found. However, compared to those not seeking sex by internet, men using the internet to meet sex partners were more likely to report fisting...

  17. Sex ratio variation in the bumblebee Bombus terrestris

    DEFF Research Database (Denmark)

    Duchateau, Marie José; Velthuis, Hayo H. W.; Boomsma, Jacobus Jan

    2004-01-01

    Bombus terrestris, bumblebees, colony development, queen control, reproductive strategies, sex allocation......Bombus terrestris, bumblebees, colony development, queen control, reproductive strategies, sex allocation...

  18. Effects of biological sex on the pathophysiology of the heart

    National Research Council Canada - National Science Library

    Fazal, Loubina; Azibani, Feriel; Vodovar, Nicolas; Cohen Solal, Alain; Delcayre, Claude; Samuel, Jane‐Lise

    2014-01-01

    .... While the effects of biological sex on cardiovascular pathophysiology have long been known, the sex-specific mechanisms mediating these processes have been further elucidated over recent years...

  19. Searching for sex-reversals to explain population demography and the evolution of sex chromosomes.

    Science.gov (United States)

    Wedekind, Claus

    2010-05-01

    Sex determination can be purely genetic (as in mammals and birds), purely environmental (as in many reptiles), or genetic but reversible by environmental factors during a sensitive period in life, as in many fish and amphibians (Wallace et al. 1999; Baroiller et al. 2009a; Stelkens & Wedekind 2010). Such environmental sex reversal (ESR) can be induced, for example, by temperature changes or by exposure to hormone-active substances. ESR has long been recognized as a means to produce more profitable single-sex cultures in fish farms (Cnaani & Levavi-Sivan 2009), but we know very little about its prevalence in the wild. Obviously, induced feminization or masculinization may immediately distort population sex ratios, and distorted sex ratios are indeed reported from some amphibian and fish populations (Olsen et al. 2006; Alho et al. 2008; Brykov et al. 2008). However, sex ratios can also be skewed by, for example, segregation distorters or sex-specific mortality. Demonstrating ESR in the wild therefore requires the identification of sex-linked genetic markers (in the absence of heteromorphic sex chromosomes) followed by comparison of genotypes and phenotypes, or experimental crosses with individuals who seem sex reversed, followed by sexing of offspring after rearing under non-ESR conditions and at low mortality. In this issue, Alho et al. (2010) investigate the role of ESR in the common frog (Rana temporaria) and a population that has a distorted adult sex ratio. They developed new sex-linked microsatellite markers and tested wild-caught male and female adults for potential mismatches between phenotype and genotype. They found a significant proportion of phenotypic males with a female genotype. This suggests environmental masculinization, here with a prevalence of 9%. The authors then tested whether XX males naturally reproduce with XX females. They collected egg clutches and found that some had indeed a primary sex ratio of 100% daughters. Other clutches seemed to

  20. Sexing code subversion, theory and representation

    CERN Document Server

    Herbst, Claudia

    2008-01-01

    Critically investigating the gender of programming in popular culture, Sexing Code proposes that the de facto representation of technical ability serves to perpetuate the age-old association of the male with intellect and reason, while identifying the fem

  1. Have sex or not? Lessons from bacteria.

    Science.gov (United States)

    Lodé, T

    2012-01-01

    Sex is one of the greatest puzzles in evolutionary biology. A true meiotic process occurs only in eukaryotes, while in bacteria, gene transcription is fragmentary, so asexual reproduction in this case really means clonal reproduction. Sex could stem from a signal that leads to increased reproductive output of all interacting individuals and could be understood as a secondary consequence of primitive metabolic reactions. Meiotic sex evolved in proto-eukaryotes to solve a problem that bacteria did not have, namely a large amount of DNA material, occurring in an archaic step of proto-cell formation and genetic exchanges. Rather than providing selective advantages through reproduction, sex could be thought of as a series of separate events which combines step-by-step some very weak benefits of recombination, meiosis, gametogenesis and syngamy. Copyright © 2012 S. Karger AG, Basel.

  2. ENUGU TO SCHOOL BASED SEX EDUCATION.

    African Journals Online (AJOL)

    Objective: To assess the knowledge and attitude to sex education among secondary school teachers in Enugu. Materials and Methods: A ... The school environment also olfers young people ..... about contraceptive practice and pregnancy.

  3. Sex trafficking of women and girls.

    Science.gov (United States)

    Deshpande, Neha A; Nour, Nawal M

    2013-01-01

    Sex trafficking involves some form of forced or coerced sexual exploitation that is not limited to prostitution, and has become a significant and growing problem in both the United States and the larger global community. The costs to society include the degradation of human and women's rights, poor public health, disrupted communities, and diminished social development. Victims of sex trafficking acquire adverse physical and psychological health conditions and social disadvantages. Thus, sex trafficking is a critical health issue with broader social implications that requires both medical and legal attention. Healthcare professionals can work to improve the screening, identification, and assistance of victims of sex trafficking in a clinical setting and help these women and girls access legal and social services.

  4. Inherent Dangers in Orogenital Sex During Pregnancy

    African Journals Online (AJOL)

    dangerous, causing even the death of the women. We carried out a search of ... KEY WORDS: Air embolism, cunnilingus, orogenital sex, pregnancy ... contained multiple case report. ... The average age of women was 20.2 years, and only one.

  5. Determining sex ratios of turtle hatchlings

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Previous status assessments of marine turtles have assumed that the natural sex ratio of a marine turtle population is 1:1 (e.g. Conant et al. 2009). However, this...

  6. Sex determination of baleen whale artefacts

    DEFF Research Database (Denmark)

    Sinding, Mikkel Holger Strander; Tervo, Outi M.; Grønnow, Bjarne

    2016-01-01

    Abstract Methods to determine the sex from tissue samples of mammals include the amplification of Y chromosome specific regions, which should only amplify from males, or amplification of homologous regions of the X and Y chromosome containing XY specific SNPs. A disadvantage of the first approach...... is that PCR failure can be misinterpreted as the identification of a female. The latter approach is proposed to identify PCR failure through non-amplification of the X homologue, which should be present in both sexes. This method is therefore potentially more suitable for molecular sexing of degraded DNA...... with a high probability of PCR failure, such as for example, ancient DNA samples. Here, we investigate the validity of this assumption regarding the use of XY homologue PCR assays for molecular sexing of ancient DNA. We tested a primer set targeting the ZFX/ZFY alleles using ancient DNA extracts from 100...

  7. Molecular Sex Differences in Human Serum

    NARCIS (Netherlands)

    J.M. Ramsey (Jordan); E. Schwarz (Emanuel); P.C. Guest (Paul); N.J.M. van Beveren (Nico); F.M. Leweke (Marcus); M. Rothermundt (Matthias); B. Bogerts (Bernhard); J. Steiner (Johann); L. Ruta (Liliana); S. Baron-Cohen (Simon); S. Bahn (Sabine)

    2012-01-01

    textabstractBackground: Sex is an important factor in the prevalence, incidence, progression, and response to treatment of many medical conditions, including autoimmune and cardiovascular diseases and psychiatric conditions. Identification of molecular differences between typical males and females c

  8. Sex i Det Nye Testamente - helst ikke!

    DEFF Research Database (Denmark)

    Hallbäck, Geert

    2013-01-01

    To holdninger til sex i Det Nye testamente: Afholdenhed og tilpasning til samfundets ægteskabsmoral, afspejler den tidlige kristendoms eskatologiske askese og den mere etablerede kristendoms tilpasning til normalsamfundet....

  9. Sex Trafficking, Law Enforcement and Perpetrator Accountability

    National Research Council Canada - National Science Library

    Holly Burkhalter

    2012-01-01

    In theory, everyone – except for criminals involved in their exploitation - agrees that children must not be in the sex industry and further, that those who prey on them must be prosecuted and punished...

  10. Sex trafficking of women and girls

    National Research Council Canada - National Science Library

    Deshpande, Neha A; Nour, Nawal M

    2013-01-01

    Sex trafficking involves some form of forced or coerced sexual exploitation that is not limited to prostitution, and has become a significant and growing problem in both the United States and the larger global community...

  11. Fast, reliable sexing of prosimian DNA

    DEFF Research Database (Denmark)

    Fredsted, Tina; Villesen, Palle

    2004-01-01

    to identify conserved regions in the amelogenin gene. Using these conserved regions, we can target species that have no sequence information. We designed a single, conserved primer pair that is useful for fast and reliable molecular sexing of prosimian primates. A single PCR yields two fragments in males......Molecular sexing of mammals is normally done by PCR amplification of Y chromosomal fragments, or coamplification of homologous fragments from both sex chromosomes. Existing primers are often unreliable for distantly related species due to mutations in primer regions. Currently...... there are no published primers for the sexing of prosimian DNA. We show that an existing method (using the zinc finger protein) based on a size difference between the X and Y homologs does not work in prosimians. Multiple alignments of distantly related mammalian species from Genbank and genome databases enabled us...

  12. Sex work on the rise. International news.

    Science.gov (United States)

    1996-01-01

    The AIDS epidemic has brought to the fore many social injustices; for instance, inappropriate laws. The groups of people most at risk of HIV/AIDS are women, young people, and sex workers. More appropriate laws are needed to protect their rights. In many instances sex workers are prosecuted for selling their services, but their clients are not prosecuted for seeking these services. Most people become sex workers so they can feed, clothe, and supply the basic needs for themselves and their families. Many sex workers are abandoned wives, mothers with no means of support, and poverty stricken people. A Health Ministry commission in Sweden proposed that prostitutes, clients, and pimps be prosecuted and be liable to imprisonment. Authorities in Scotland, where prostitution is illegal, have granted licenses to more than 20 clubs in Edinburgh in which sex is for sale. In the UK, the Royal College of Nursing called for a measure to decriminalize prostitution and to introduce licensed, regulated brothels. The legalization of sex clubs and brothels will occur soon in the Netherlands. In Poland, 30,000-50,000 youth, 33% of whom are underage, sell sex during holidays. Organizations are beginning to work only with male prostitutes in Belgium. In the countries of the former Soviet Union and China, prostitution is becoming more and more common. Some young girls in these countries practice currency prostitution. In almost all Asian countries except Thailand condom use is low; yet prostitution and sexually transmitted diseases are very common. Some people participate in the corrupt trade in women from Nepal to supply the sex market in Bombay, India. Sex tourism is still common in cities of Eastern Europe and the former USSR and in areas where tourism is increasing. There are more than 1 million prostitutes aged under 16 in eight Asian countries, with 400,000 in India. Sweden and the UK have taken steps to prosecute natives who have sex with children abroad. Philippine authorities

  13. Juvenile sex-only and sex-plus offenders: an exploratory study on criminal profiles.

    Science.gov (United States)

    van Wijk, A Ph; Mali, S R F; Bullens, R A R

    2007-08-01

    In this study, research was done on the criminal profiles of a large group of juvenile sex-only and sex-plus (sex and other offenses) delinquents (N = 4,430) in the Netherlands. Use was made of information from police records. Results show that sex-plus offenders start their careers earlier, that more of these offenders are of non-Dutch origin, that they commit more crimes, and will partly continue their criminal career after their adolescence. Juvenile sex-only offenders rarely go on committing crimes. In sex-plus offenders, sexual crimes play only a minor role in their total crime repertory. As time goes by, their criminal career will develop into the direction of property crimes. Finally, the implications and limitations of this study will be discussed.

  14. New Y chromosomes and early stages of sex chromosome differentiation: sex determination in Megaselia

    Indian Academy of Sciences (India)

    Walther Traut

    2010-09-01

    The phorid fly Megaselia scalaris is a laboratory model for the turnover and early differentiation of sex chromosomes. Isolates from the field have an XY sex-determining mechanism with chromosome pair 2 acting as X and Y chromosomes. The sex chromosomes are homomorphic but display early signs of sex chromosome differentiation: a low level of molecular differences between X and Y. The male-determining function $(M)$, maps to the distal part of the Y chromosome’s short arm. In laboratory cultures, new Y chromosomes with no signs of a molecular differentiation arise at a low rate, probably by transposition of to these chromosomes. Downstream of the primary signal, the homologue of the Drosophila doublesex (dsx) is part of the sex-determining pathway while Sex-lethal (Sxl), though structurally conserved, is not.

  15. Sex Steroids and the Dentate Gyrus

    OpenAIRE

    Hajszan, Tibor; Milner, Teresa A.; Leranth, Csaba

    2007-01-01

    In the late 1980s, the finding that the dentate gyrus contains more granule cells in the male than in the female of certain mouse strains provided the first indication that the dentate gyrus is a significant target for the effects of sex steroids during development. Gonadal hormones also play a crucial role in shaping the function and morphology of the adult brain. Besides reproduction-related processes, sex steroids participate in higher brain operations such as cognition and mood, in which ...

  16. Sex differences in intracranial arterial bifurcations

    DEFF Research Database (Denmark)

    Lindekleiv, Haakon M; Valen-Sendstad, Kristian; Morgan, Michael K;

    2010-01-01

    Subarachnoid hemorrhage (SAH) is a serious condition, occurring more frequently in females than in males. SAH is mainly caused by rupture of an intracranial aneurysm, which is formed by localized dilation of the intracranial arterial vessel wall, usually at the apex of the arterial bifurcation. T....... The female preponderance is usually explained by systemic factors (hormonal influences and intrinsic wall weakness); however, the uneven sex distribution of intracranial aneurysms suggests a possible physiologic factor-a local sex difference in the intracranial arteries....

  17. Sex trafficking and the exploitation of adolescents.

    Science.gov (United States)

    McClain, Natalie M; Garrity, Stacy E

    2011-01-01

    Human trafficking affects a surprisingly large number of adolescents around the globe. Women and girls make up the majority of sex trafficking victims. Nurses must be aware of sex trafficking as a form of sexual violence in the adolescent population. Nurses can play a role in identifying, intervening, and advocating for victims of human trafficking as they currently do for patients that are the victims of other types of violent crimes.

  18. History of commercializing sexed semen for cattle.

    Science.gov (United States)

    Garner, D L; Seidel, G E

    2008-04-15

    Although the basic principles controlling the sex of mammalian offspring have been known for a relatively long time, recent application of certain modern cellular methodologies has led to development of a flow cytometric system capable of differentiating and separating living X- and Y-chromosome-bearing sperm in amounts suitable for AI and therefore, commercialization of this sexing technology. After a very long history of unsuccessful attempts to differentiate between mammalian sperm that produce males from those that produce females, a breakthrough came in 1981 when it was demonstrated that precise DNA content could be measured. Although these initial measurements of DNA content killed the sperm in the process, they led to the ultimate development of a sperm sorting system that was capable, not only of differentiating between live X- and Y-sperm, but of sorting them into relatively pure X- and Y-sperm populations without obvious cellular damage. Initial efforts to predetermine the sex of mammalian offspring in 1989 required surgical insemination, but later enhancements provided sex-sorted sperm in quantities suitable for use with IVF. Subsequent advances in flow sorting provided minimal numbers of sperm sufficient for use in AI. It was not until the flow cytometric sorting system was improved greatly and successful cryopreservation of sex-sorted bull sperm was developed that efficacious approaches to commercialization of sexed semen could be implemented worldwide in cattle. A number of companies now offer sex-sorted bovine sperm. Innovative approaches by a diverse group of scientists along with advances in computer science, biophysics, cell biology, instrumentation, and applied reproductive physiology provided the basis for commercializing sexed semen in cattle.

  19. Sex differences in intracranial arterial bifurcations

    DEFF Research Database (Denmark)

    Lindekleiv, Haakon M; Valen-Sendstad, Kristian; Morgan, Michael K

    2010-01-01

    Subarachnoid hemorrhage (SAH) is a serious condition, occurring more frequently in females than in males. SAH is mainly caused by rupture of an intracranial aneurysm, which is formed by localized dilation of the intracranial arterial vessel wall, usually at the apex of the arterial bifurcation....... The female preponderance is usually explained by systemic factors (hormonal influences and intrinsic wall weakness); however, the uneven sex distribution of intracranial aneurysms suggests a possible physiologic factor-a local sex difference in the intracranial arteries....

  20. Sue's Oppressed Sex in Jude the Obscure

    Institute of Scientific and Technical Information of China (English)

    陈娟

    2010-01-01

    Using ecofeminist literary criticism.the paper analyzes women's unjustified and dominated sex in Jude the Obscure.Sue,as a"New Woman"in the male-dominated society,is dominated and oppressed in sex.Sue's subordinated position illustrates Hardy's sympathy for Victorian women and his opposition to the unjustified domination of women.He advocates a harmonious relationship among people in the society.

  1. [Self concept, sex and marital status].

    Science.gov (United States)

    Tamayo, A

    1986-09-01

    The purpose of this research was to study the influence of sex and marital status on the self-concept. The Factorial Selfconcept Scale was administered to a sample of 855 university students. The 2 X 2 ANOVAS revealed a significant main effect of the two independent variables on several factors of the Scale, as well as an interaction sex X marital status. Results are consistent with a coherent body of previous research.

  2. Sex, Drugs, and Cognition: Effects of Marijuana†

    OpenAIRE

    Anderson, Beth M.; Rizzo, Matthew; Block, Robert I.; Pearlson, Godfrey D.; O'Leary, Daniel S.

    2010-01-01

    Despite the knowledge that many drugs affect men and women differently, few studies exploring the effects of marijuana use on cognition have included women. Findings from both animal and human studies suggest marijuana may have more marked effects in women. This study examined sex differences in the acute effects of marijuana on cognition in 70 (n= 35 male, 35 female) occasional users of marijuana. Tasks were chosen to tap a wide variety of cognitive domains affected by sex and/or marijuana i...

  3. From Dreamed Sex to Advertised Sex: Sexual Deals in Daily Press

    OpenAIRE

    Teixeira, Filomena; Marques, Fernando M.

    2014-01-01

    Media are becoming increasingly permeable to speeches that bring into play pornographization processes of the public space. The sex ads published in the daily press represent an important example of this phenomenon. By resorting to sex trade practices as positive, relaxing and pleasurable experiences, they embody a particular way of producing identities. The present study is of qualitative nature and aims to map the enunciation modes and persuasion strategies that characterize the sex ads in ...

  4. Sex trafficking, sexual risk, sexually transmitted infection and reproductive health among female sex workers in Thailand.

    Science.gov (United States)

    Decker, Michele R; McCauley, Heather L; Phuengsamran, Dusita; Janyam, Surang; Silverman, Jay G

    2011-04-01

    The trafficking of women and girls for sexual exploitation is an internationally recognised form of gender-based violence, and is thought to confer unique sexual and reproductive health vulnerabilities. To date, little research has compared sexual risk or health outcomes among female sex workers (FSWs) on the basis of experiences of sex trafficking. To compare experiences of sexual risk and sexual and reproductive health outcomes among FSWs on the basis of experiences of trafficking as an entry mechanism to sex work. Data from a national sample of FSWs in Thailand (n=815) was used to assess (a) the prevalence of sex trafficking as an entry mechanism into sex work and (b) associations of sex trafficking with sexual risk and health outcomes. Approximately 10% of FSWs met criteria for trafficking as an entry mechanism to sex work. Compared with their non-trafficked counterparts, sex-trafficked FSWs were more likely to have experienced sexual violence at initiation to sex work (adjusted risk ratio (ARR) 2.29, 95% CI 1.11 to 4.72), recent workplace violence or mistreatment (ARR 1.38, 95% CI 1.13 to 1.67), recent condom failure (ARR 1.80, 95% CI 1.15 to 2.80), condom non-use (ARR 3.35, 95% CI 1.49 to 7.52) and abortion (ARR 2.83, 95% CI 1.48 to 5.39). Both the prevalence of sex trafficking as an entry mechanism to sex work and the threats to sexual and reproductive health observed on the basis of trafficking status show the need for comprehensive efforts to identify and support this vulnerable population. Moreover, existing STI/HIV-prevention programming may be stymied by the limited condom-use capacity and high levels of violence observed among those trafficked into sex work.

  5. The genomics of plant sex chromosomes.

    Science.gov (United States)

    Vyskot, Boris; Hobza, Roman

    2015-07-01

    Around six percent of flowering species are dioecious, with separate female and male individuals. Sex determination is mostly based on genetics, but morphologically distinct sex chromosomes have only evolved in a few species. Of these, heteromorphic sex chromosomes have been most clearly described in the two model species - Silene latifolia and Rumex acetosa. In both species, the sex chromosomes are the largest chromosomes in the genome. They are hence easily distinguished, can be physically separated and analyzed. This review discusses some recent experimental data on selected model dioecious species, with a focus on S. latifolia. Phylogenetic analyses show that dioecy in plants originated independently and repeatedly even within individual genera. A cogent question is whether there is genetic degeneration of the non-recombining part of the plant Y chromosome, as in mammals, and, if so, whether reduced levels of gene expression in the heterogametic sex are equalized by dosage compensation. Current data provide no clear conclusion. We speculate that although some transcriptome analyses indicate the first signs of degeneration, especially in S. latifolia, the evolutionary processes forming plant sex chromosomes in plants may, to some extent, differ from those in animals.

  6. Sex differences associated with intermittent swim stress.

    Science.gov (United States)

    Warner, Timothy A; Libman, Matthew K; Wooten, Katherine L; Drugan, Robert C

    2013-11-01

    Various animal models of depression have been used to seek a greater understanding of stress-related disorders. However, there is still a great need for novel research in this area, as many individuals suffering from depression are resistant to current treatment methods. Women have a higher rate of depression, highlighting the need to investigate mechanisms of sex differences. Therefore, we employed a new animal model to assess symptoms of depression, known as intermittent swim stress (ISS). In this model, the animal experiences 100 trials of cold water swim stress. ISS has already been shown to cause signs of behavioral depression in males, but has yet to be assessed in females. Following ISS exposure, we looked at sex differences in the Morris water maze and forced swim test. The results indicated a spatial learning effect only in the hidden platform task between male and female controls, and stressed and control males. A consistent spatial memory effect was only seen for males exposed to ISS. In the forced swim test, both sexes exposed to ISS exhibited greater immobility, and the same males and females also showed attenuated climbing and swimming, respectively. The sex differences could be due to different neural substrates for males and females. The goal of this study was to provide the first behavioral examination of sex differences following ISS exposure, so the stage of estrous cycle was not assessed for the females. This is a necessary future direction for subsequent experiments. The current article highlights the importance of sex differences in response to stress.

  7. Determination of sex by armbone dimensions.

    Science.gov (United States)

    Aye, Victor Omakoji

    2010-06-15

    Sex determination is a vital part of the medico-legal system but can be difficult in cases where the body is damaged. The purpose of this study was to develop a technique for sex determination from three arm-bone dimensions (wrist circumference, arm length and arm span). This knowledge can be applied in cases of mass disaster, homicide and events such as sports. Data were collected for 95 Nigerian male students and 90 Nigerian female students using physical anthropometry. Discriminant function presented the wrist dimension as the dominant contributor in this study. Combination equations for both the wrist and arm-span dimensions correctly classified sex (male/female) with an accuracy rate of 84.9%. On cross-validation, sex was also established with the same 84.9% accuracy rate. Sex determination was higher in males. Sexual dimorphism was established in this study, although the wrist circumference was more distinct than arm span; a combination of both generated sex with an accuracy prediction rate of 84.9%.

  8. Sex differences in anxiety and emotional behavior

    Science.gov (United States)

    Donner, Nina C.; Lowry, Christopher A.

    2013-01-01

    Research has elucidated causal links between stress exposure and the development of anxiety disorders, but due to the limited use of female or sex-comparative animal models, little is known about the mechanisms underlying sex differences in those disorders. This is despite an overwhelming wealth of evidence from the clinical literature that the prevalence of anxiety disorders is about twice as high in women compared to men, in addition to gender differences in severity and treatment efficacy. We here review human gender differences in generalized anxiety disorder, panic disorder, posttraumatic stress disorder and anxiety-relevant biological functions, discuss the limitations of classic conflict anxiety tests to measure naturally occurring sex differences in anxiety-like behaviors, describe sex-dependent manifestation of anxiety states after gestational, neonatal, or adolescent stressors, and present animal models of chronic anxiety states induced by acute or chronic stressors during adulthood. Potential mechanisms underlying sex differences in stress-related anxiety states include emerging evidence supporting the existence of two anatomically and functionally distinct serotonergic circuits that are related to the modulation of conflict anxiety and panic-like anxiety, respectively. We discuss how these serotonergic circuits may be controlled by reproductive steroid hormone-dependent modulation of crfr1 and crfr2 expression in the midbrain dorsal raphe nucleus and by estrous stage-dependent alterations of γ-aminobutyric acid (GABAergic) neurotransmission in the periaqueductal gray, ultimately leading to sex differences in emotional behavior. PMID:23588380

  9. The evolution of sex chromosomes in organisms with separate haploid sexes.

    Science.gov (United States)

    Immler, Simone; Otto, Sarah Perin

    2015-03-01

    The evolution of dimorphic sex chromosomes is driven largely by the evolution of reduced recombination and the subsequent accumulation of deleterious mutations. Although these processes are increasingly well understood in diploid organisms, the evolution of dimorphic sex chromosomes in haploid organisms (U/V) has been virtually unstudied theoretically. We analyze a model to investigate the evolution of linkage between fitness loci and the sex-determining region in U/V species. In a second step, we test how prone nonrecombining regions are to degeneration due to accumulation of deleterious mutations. Our modeling predicts that the decay of recombination on the sex chromosomes and the addition of strata via fusions will be just as much a part of the evolution of haploid sex chromosomes as in diploid sex chromosome systems. Reduced recombination is broadly favored, as long as there is some fitness difference between haploid males and females. The degeneration of the sex-determining region due to the accumulation of deleterious mutations is expected to be slower in haploid organisms because of the absence of masking. Nevertheless, balancing selection often drives greater differentiation between the U/V sex chromosomes than in X/Y and Z/W systems. We summarize empirical evidence for haploid sex chromosome evolution and discuss our predictions in light of these findings.

  10. Comparing Sex Buyers With Men Who Do Not Buy Sex: New Data on Prostitution and Trafficking.

    Science.gov (United States)

    Farley, Melissa; Golding, Jacqueline M; Matthews, Emily Schuckman; Malamuth, Neil M; Jarrett, Laura

    2015-08-31

    We investigated attitudes and behaviors associated with prostitution and sexual aggression among 101 men who buy sex and 101 age-, education-, and ethnicity-matched men who did not buy sex. Both groups tended to accept rape myths, be aware of harms of prostitution and trafficking, express ambivalence about the nature of prostitution, and believe that jail time and public exposure are the most effective deterrents to buying sex. Sex buyers were more likely than men who did not buy sex to report sexual aggression and likelihood to rape. Men who bought sex scored higher on measures of impersonal sex and hostile masculinity and had less empathy for prostituted women, viewing them as intrinsically different from other women. When compared with non-sex-buyers, these findings indicate that men who buy sex share certain key characteristics with men at risk of committing sexual aggression as documented by research based on the leading scientific model of the characteristics of non-criminal sexually aggressive men, the Confluence Model of sexual aggression.

  11. Analysis of the Offspring Sex Ratio of Chicken by Using Molecular Sexing

    Institute of Scientific and Technical Information of China (English)

    FENG Yan-ping; GONG Yan-zhang; Nabeel Ahmed Affara; PENG Xiu-li; YUAN Jin-feng; ZHAO Rui-xia; Mohammed Yusuf; Osman Jeffer; ZHANG Shu-jun

    2006-01-01

    The overall sex ratio of offspring (dead embryos and hatch chicks) from all the fertilized eggs of 140 hens collected for30 days was studied using duplex PCR of certain fragments of sex chromosomes. Additional 894 dead embryos over a period of 21 days of incubation were also investigated to verify the sex ratio of the dead embryos. The sex of the early dead embryos was identified using this molecular sexing technique. The sex ratio of the hatch chicks and the total offspring of the hens investigated in this experiment did not differ from the expected sex ratio (i.e., 1:1). However, the number of female dead embryos was significantly more than that of males. The data indicated that the different physiologic function of males and females contributed to female-biased mortality during incubation. It was also found by further analysis that the sex ratios of the offspring of some hens were significantly biased to female or male over the period investigated, which suggested that the sex ratio of offspring might be influenced by the maternal condition to some degrees.

  12. Neo-sex chromosomes of Ronderosia bergi: insight into the evolution of sex chromosomes in grasshoppers.

    Science.gov (United States)

    Palacios-Gimenez, O M; Marti, D A; Cabral-de-Mello, D C

    2015-09-01

    Sex chromosomes have evolved many times from morphologically identical autosome pairs, most often presenting several recombination suppression events, followed by accumulation of repetitive DNA sequences. In Orthoptera, most species have an X0♂ sex chromosome system. However, in the subfamily Melanoplinae, derived variants of neo-sex chromosomes (neo-XY♂ or neo-X1X2Y♂) emerged several times. Here, we examined the differentiation of neo-sex chromosomes in a Melanoplinae species with a neo-XY♂/XX♀ system, Ronderosia bergi, using several approaches: (i) classical cytogenetic analysis, (ii) mapping via fluorescent in situ hybridization of some selected repetitive DNA sequences and microdissected sex chromosomes, and (iii) immunolocalization of distinct histone modifications. The microdissected sex chromosomes were also used as sources for Polymerase chain reaction (PCR) amplification of RNA-coding multigene families, to study variants related to the sex chromosomes. Our data suggest that the R. bergi neo-Y has become differentiated after its formation by a Robertsonian translocation and inversions, and has accumulated repetitive DNA sequences. Interestingly, the ex autosomes incorporated into the neo-sex chromosomes retain some autosomal post-translational histone modifications, at least in metaphase I, suggesting that the establishment of functional modifications in neo-sex chromosomes is slower than their sequence differentiation.

  13. Combating human trafficking in the sex trade: can sex workers do it better?

    Science.gov (United States)

    Jana, Smarajit; Dey, Bharati; Reza-Paul, Sushena; Steen, Richard

    2014-12-01

    The dominant anti-trafficking paradigm conflates trafficking and sex work, denying evidence that most sex workers choose their profession and justifying police actions that disrupt communities, drive sex workers underground and increase vulnerability. We review an alternative response to combating human trafficking and child prostitution in the sex trade, the self-regulatory board (SRB) developed by Durbar Mahila Samanwaya Committee (DMSC, Sonagachi). DMSC-led interventions to remove minors and unwilling women from sex work account for over 80% of successful 'rescues' reported in West Bengal. From 2009 through 2011, 2195 women and girls were screened by SRBs: 170 (7.7%) minors and 45 (2.1%) unwilling adult women were assisted and followed up. The remaining 90.2% received counselling, health care and the option to join savings schemes and other community programmes designed to reduce sex worker vulnerability. Between 1992 and 2011 the proportion of minors in sex work in Sonagachi declined from 25 to 2%. With its universal surveillance of sex workers entering the profession, attention to rapid and confidential intervention and case management, and primary prevention of trafficking-including microcredit and educational programmes for children of sex workers-the SRB approach stands as a new model of success in anti-trafficking work. © The Author 2013. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Sex bias in paediatric autoimmune disease - Not just about sex hormones?

    Science.gov (United States)

    Chiaroni-Clarke, Rachel C; Munro, Jane E; Ellis, Justine A

    2016-05-01

    Autoimmune diseases affect up to 10% of the world's population, and approximately 80% of those affected are female. The majority of autoimmune diseases occur more commonly in females, although some are more frequent in males, while others show no bias by sex. The mechanisms leading to sex biased disease prevalence are not well understood. However, for adult-onset autoimmune disease, at least some of the cause is usually ascribed to sex hormones. This is because levels of sex hormones are one of the most obvious physiological differences between adult males and females, and their impact on immune system function is well recognised. While for paediatric-onset autoimmune diseases a sex bias is not as common, there are several such diseases for which one sex predominates. For example, the oligoarticular subtype of juvenile idiopathic arthritis (JIA) occurs in approximately three times more girls than boys, with a peak age of onset well before the onset of puberty, and at a time when levels of androgen and oestrogen are low and not strikingly different between the sexes. Here, we review potential explanations for autoimmune disease sex bias with a particular focus on paediatric autoimmune disease, and biological mechanisms outside of sex hormone differences.

  15. Sex hormones alter sex ratios in the Indian skipper frog, Euphlyctis cyanophlyctis: Determining sensitive stages for gonadal sex reversal.

    Science.gov (United States)

    Phuge, S K; Gramapurohit, N P

    2015-09-01

    In amphibians, although genetic factors are involved in sex determination, gonadal sex differentiation can be modified by exogenous steroid hormones suggesting a possible role of sex steroids in regulating the process. We studied the effect of testosterone propionate (TP) and estradiol-17β (E2) on gonadal differentiation and sex ratio at metamorphosis in the Indian skipper frog, Euphlyctis cyanophlyctis with undifferentiated type of gonadal differentiation. A series of experiments were carried out to determine the optimum dose and sensitive stages for gonadal sex reversal. Our results clearly indicate the importance of sex hormones in controlling gonadal differentiation of E. cyanophlyctis. Treatment of tadpoles with 10, 20, 40, and 80μg/L TP throughout larval period resulted in the development of 100% males at metamorphosis at all concentrations. Similarly, treatment of tadpoles with 40μg/L TP during ovarian and testicular differentiation resulted in the development of 90% males, 10% intersexes and 100% males respectively. Treatment of tadpoles with 10, 20, 40, and 80μg/L E2 throughout larval period likewise produced 100% females at all concentrations. Furthermore, exposure to 40μg/L E2 during ovarian and testicular differentiation produced 95% females, 5% intersexes and 91% females, 9% intersexes respectively. Both TP and E2 were also effective in advancing the stages of gonadal development. Present study shows the effectiveness of both T and E2 in inducing complete sex reversal in E. cyanophlyctis. Generally, exposure to E2 increased the larval period resulting in significantly larger females than control group while the larval period of control and TP treated groups was comparable. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Gender-stereotyping and cognitive sex differences in mixed- and same-sex groups.

    Science.gov (United States)

    Hirnstein, Marco; Coloma Andrews, Lisa; Hausmann, Markus

    2014-11-01

    Sex differences in specific cognitive abilities are well documented, but the biological, psychological, and sociocultural interactions that may underlie these differences are largely unknown. We examined within a biopsychosocial approach how gender stereotypes affect cognitive sex differences when adult participants were tested in mixed- or same-sex groups. A total of 136 participants (70 women) were allocated to either mixed- or same-sex groups and completed a battery of sex-sensitive cognitive tests (i.e., mental rotation, verbal fluency, perceptual speed) after gender stereotypes or gender-neutral stereotypes (control) were activated. To study the potential role of testosterone as a mediator for group sex composition and stereotype boost/threat effects, saliva samples were taken before the stereotype manipulation and after cognitive testing. The results showed the typical male and female advantages in mental rotation and verbal fluency, respectively. In general, men and women who were tested in mixed-sex groups and whose gender stereotypes had not been activated performed best. Moreover, a stereotype threat effect emerged in verbal fluency with reduced performance in gender stereotyped men but not women. Testosterone levels did not mediate the effects of group sex composition and stereotype threat nor did we find any relationship between testosterone and cognitive performance in men and women. Taken together, the findings suggest that an interaction of gender stereotyping and group sex composition affects the performance of men and women in sex-sensitive cognitive tasks. Mixed-sex settings can, in fact, increase cognitive performance as long as gender-stereotyping is prevented.

  17. Genetic architecture and the evolution of sex.

    Science.gov (United States)

    Lohaus, Rolf; Burch, Christina L; Azevedo, Ricardo B R

    2010-01-01

    Theoretical investigations of the advantages of sex have tended to treat the genetic architecture of organisms as static and have not considered that genetic architecture might coevolve with reproductive mode. As a result, some potential advantages of sex may have been missed. Using a gene network model, we recently showed that recombination imposes selection for robustness to mutation and that negative epistasis can evolve as a by-product of this selection. These results motivated a detailed exploration of the mutational deterministic hypothesis, a hypothesis in which the advantage of sex depends critically on epistasis. We found that sexual populations do evolve higher mean fitness and lower genetic load than asexual populations at equilibrium, and, under moderate stabilizing selection and large population size, these equilibrium sexual populations resist invasion by asexuals. However, we found no evidence that these long- and short-term advantages to sex were explained by the negative epistasis that evolved in our experiments. The long-term advantage of sex was that sexual populations evolved a lower deleterious mutation rate, but this property was not sufficient to account for the ability of sexual populations to resist invasion by asexuals. The ability to resist asexual invasion was acquired simultaneously with an increase in recombinational robustness that minimized the cost of sex. These observations provide the first direct evidence that sexual reproduction does indeed select for conditions that favor its own maintenance. Furthermore, our results highlight the importance of considering a dynamic view of the genetic architecture to understand the evolution of sex and recombination.

  18. The evolution of female sex pheromones

    Institute of Scientific and Technical Information of China (English)

    Ally R.HARARI; Hadass STEINITZ

    2013-01-01

    The role of female sex pheromones in natural selection,particularly as a means for species recognition to avoid the generation of hybrid offspring with low fitness,has been widely explored and is generally accepted by scholars.However,the significance of sex pheromones in shaping mate choice (sexual selection) and in competition over breeding resources (social selection) has been largely ignored.The effect of sexual selection on sex pheromones as a sexually dimorphic signaling trait has been discounted because the amount of pheromone released by females is typically minute,while the role of sex pheromones in competition over breeding resources (other than mates) has not yet been considered.As a result of natural selection,variation in sex pheromones among females is expected to be low,and males are not expected to choose their mates among pheromone-releasing conspecific females.Sexual selection,on the other hand,should drive the increase in pheromone variance among females,and males are expected to choose females based on this variation.Moreover,social selection resulting from more general social interactions,for example competition among females for breeding sites and food,should also promote variance among female sex pheromones.Here,we review the current evidence for each of the three selection processes acting on sex pheromones of female moths as an advertising trait.We suggest that the three selection types are not mutually exclusive but rather act together to promote different fitness components in diverse ecological situations.

  19. Mother's occupation and sex ratio at birth

    Directory of Open Access Journals (Sweden)

    Amiot Volodymyr

    2010-05-01

    Full Text Available Abstract Background Many women are working outside of the home, occupying a multitude of jobs with varying degrees of responsibilities and levels of psychological stress. We investigated whether different job types in women are associated with child sex at birth, with the hypothesis that women in job types, which are categorized as "high psychological stress" jobs, would be more likely to give birth to a daughter than a son, as females are less vulnerable to unfavourable conditions during conception, pregnancy and after parturition, and are less costly to carry to term. Methods We investigated the effects of mother's age, maternal and paternal job type (and associated psychological stress levels and paternal income on sex ratio at birth. Our analyses were based on 16,384 incidences of birth from a six-year (2000 to 2005 inclusive childbirth dataset from Addenbrooke's Hospital in Cambridge, UK. We obtained a restricted data set from Addenbrooke's hospital with: maternal age, maternal and paternal occupations, and whether or not the child was first-born. Results Women in job types that were categorized as "high stress" were more likely to give birth to daughters, whereas women in job types that were categorized as "low stress" had equal sex ratios or a slight male bias in offspring. We also investigated whether maternal age, and her partner's income could be associated with reversed offspring sex ratio. We found no association between mother's age, her partner's job stress category or partner income on child sex. However, there was an important interaction between job stress category and partner income in some of the analyses. Partner income appears to attenuate the association between maternal job stress and sex ratios at moderate-income levels, and reverse it at high-income levels. Conclusions To our knowledge this is the first report on the association between women's job type stress categories and offspring sex ratio in humans, and the

  20. Sex Role Stereotyping in Saturday Morning Cartoon Shows.

    Science.gov (United States)

    Mayes, Sandra L.; Valentine, K. B.

    1979-01-01

    Explores the role children's cartoon programs may play in forming sex role identities in children through the presentation of sex-typed personality attributes of the cartoon characters. Fourteen dependent variables of cartoon character personality were analyzed by sex of the character and sex of the viewer. (JVP)

  1. Sex Roles and Yielded/Expressed Self-Control.

    Science.gov (United States)

    Ganong, Lawrence H.; Coleman, Marilyn

    1987-01-01

    Results of a study of the impact of sex and sex role orientation on reported self-control behaviors showed that sex did not affect self-control or satisfaction with self-control, but sex role orientation did. Androgynous persons reported using more expressed self-control than others. (PS)

  2. Risky Business: The Market for Unprotected Commercial Sex.

    Science.gov (United States)

    Gertler, Paul; Shah, Manisha; Bertozzi, Stefano M.

    2005-01-01

    While condoms are an effective defense against the transmission of HIV, large numbers of sex workers are not using them. We argue that some sex workers are willing to take the risk because clients are willing to pay more to avoid using condoms. Using data from Mexico, we estimate that sex workers received a 23 percent premium for unprotected sex.…

  3. Sex differences in the human peripheral blood transcriptome

    NARCIS (Netherlands)

    Jansen, R.; Batista, S.; Brooks, A.I.; Tischfield, J.A.; Willemsen, G.; Grootheest, G. van; Hottenga, J.J.; Milaneschi, Y.; Mbarek, H.; Madar, V.; Peyrot, W.J.; Vink, J.M.; Verweij, C.L.; Geus, E.J.C. de; Smit, J.H.; Wright, F.A.; Sullivan, P.F.; Boomsma, D.I.; Penninx, B.W.J.H.

    2014-01-01

    Background: Genomes of men and women differ in only a limited number of genes located on the sex chromosomes, whereas the transcriptome is far more sex-specific. Identification of sex-biased gene expression will contribute to understanding the molecular basis of sex-differences in complex traits and

  4. Sex Roles and Yielded/Expressed Self-Control.

    Science.gov (United States)

    Ganong, Lawrence H.; Coleman, Marilyn

    1987-01-01

    Results of a study of the impact of sex and sex role orientation on reported self-control behaviors showed that sex did not affect self-control or satisfaction with self-control, but sex role orientation did. Androgynous persons reported using more expressed self-control than others. (PS)

  5. Preliminary Validation of the Sex Trafficking Attitudes Scale.

    Science.gov (United States)

    Houston-Kolnik, Jaclyn D; Todd, Nathan R; Wilson, Midge

    2016-09-01

    This study presents the Sex Trafficking Attitudes Scale (STAS), assessing cognitive, behavioral, and affective attitudes toward the sex trafficking of women and girls. Across two studies, exploratory and confirmatory factor analyses revealed and confirmed six subscales: (a) Knowledge About Sex Trafficking, (b) Awareness of Sex Trafficking, (c) Attitudes Toward Ability to Leave Sex Trafficking, (d) Attitudes Toward Helping Survivors, (e) Empathic Reactions Toward Sex Trafficking, and (f) Efficacy to Reduce Sex Trafficking. Results showed support for convergent validity as the subscales were associated with related measures. The STAS holds promise to expand research and inform efforts to support trafficking survivors.

  6. Mechanism of IL-6 expression in THP-1 cells induced by type ⅣB pili of Salmonella typhi%伤寒杆菌ⅣB型菌毛诱导THP-1细胞IL-6表达的机制探讨

    Institute of Scientific and Technical Information of China (English)

    汪付兵; 涂建成

    2013-01-01

    目的 探讨伤寒杆菌ⅣB型菌毛诱导THP-1细胞IL-6表达的机制.方法 将THP-1细胞或人外周血单个核细胞PBMC分别与有ⅣB型菌毛的A21-6菌、缺失ⅣB型菌毛的pilS菌共同孵育,ELISA法检测IL-6水平,荧光素酶报道基因分析法检测核转录因子(NF)-κB活化水平;用蛋白激酶C(PKC)活化抑制剂DECA预处THP-1细胞,然后以A21-6菌诱导,测定NF-κB活化水平和IL-6水平.结果 THP-1细胞或PBMC经有ⅣB型菌毛的A21-6菌诱导后,IL-6的产生水平以及NF-κB活化水平均显著高于相应对照组.PKC活化抑制剂DECA一定程度上能够抑制ⅣB型菌毛诱导的THP-1细胞NF-κB活化水平和IL-6水平.结论 ⅣB型菌毛作为细菌一种重要致病因素,经由PKC-NF-κB通路促进THP-1细胞的IL-6表达.%Objective To investigate the mechanism of IL-6 expression in THP-1 cells induced by type Ⅳ B pili of Salmonella typhi through activation of PKC-NF-κB pathway.Methods THP-1 cells and peripheral blood mononuclear cell (PBMC) were incubated with the Salmonella typhi strain A21-6 or Salmonella typhi strain pilS-respectively,the level of IL-6 was detected by ELISA,the activity of NF-κB was measured by luciferase reporter gene assay.THP-1 cells pretreated with PKC inhibitor DECA were induced by the Salmonella typhi strain A21-6,the level of IL-6 and the activity of NF-κB were detected as above.Results The type ⅣB piliated Salmonella typhi strain A21-6 could stimulate significantly higher expression of IL-6 and activity of NF-κB than those of typhi nonpiliated strain pilS-.The PKC inhibitor DECA reduced the expression of IL-6 and the activity of NF-κB induced by the piliated Salmonella typhi strain A21-6.Conclusion Type Ⅳ B pili as an important pathogenic bacterium,promotes the expression of IL-6 in THP-1 cells via the PKC-NF-κB pathway.

  7. Heritability of sex tendency in a harpacticoid copepod, Tigriopus californicus.

    Science.gov (United States)

    Voordouw, Maarten J; Anholt, Bradley R

    2002-09-01

    Systems with genetic variation for the primary sex ratio are important for testing sex-ratio theory and for understanding how this variation is maintained. Evidence is presented for heritable variation of the primary sex ratio in the harpacticoid copepod Tigriopus californicus. Variation in the primary sex ratio among families cannot be accounted for by Mendelian segregation of sex chromosomes. The covariance in sex phenotype between full-sibling clutches and between mothers and offspring suggests that this variation has a polygenic basis. Averaged over four replicates, the full-sibling heritability of sex tendency is 0.13 +/- 0.040; and the mother-offspring heritability of sex tendency is 0.31 +/- 0.216. Genetic correlations in the sex phenotype across two temperature treatments indicate large genotype-by-temperature interactions. Future experiments need to distinguish between zygotic, parental, or cytoplasmic mechanisms of sex determination in T. californicus.

  8. Parental provisioning in relation to offspring sex and sex ratio in the great tit (Parus major)

    NARCIS (Netherlands)

    Michler, Stephanie P. M.; Bleeker, Maarten; van der Velde, Marco; Both, Christiaan; Komdeur, Jan; Tinbergen, Joost M.

    2010-01-01

    Sex-biased parental care is expected if the offspring sexes differ in their energetic needs or if they differentially affect their parents' reproductive success after independence. Furthermore, parents should adjust provisioning rate and prey size to the needs of individual nestlings and the entire

  9. Cancer risk in opposite-sex and same-sex twins

    DEFF Research Database (Denmark)

    Juel Ahrenfeldt, Linda

    2015-01-01

    Twin pregnancies are characterized by simultaneous development of two fetuses that share the womb. An interest in opposite-sex (OS) twins, twin pairs consisting of one male and one female, comes from animal studies that showed that exposure to sex hormones is influenced by the position of the fetus...

  10. Sex Differences in the Value of Parents versus Same-Sex Peers

    Directory of Open Access Journals (Sweden)

    Joyce F. Benenson

    2008-01-01

    Full Text Available The current research examined the hypothesis that males derive greater benefits than females do from cooperation with same-sex peers versus parents. In Study 1, 194 children, early adolescents, older adolescents, and adults from Brussels, Belgium predicted whether parents or same-sex peers would provide more benefits to a typical individual of their same age and sex. Results showed that at all four age levels, compared with females, males predicted that same-sex peers would provide more benefits relative to parents. Study 2 was designed to examine which benefits same-sex peers relative to parents provide more for males than females. In Study 2, 50 young adults from Montreal, Canada were asked to report to what extent same-sex peers and parents satisfied physical needs, fulfilled socioemotional needs, and helped with acquiring societal skills over the past year. Males more than females reported that same-sex peers relative to parents satisfied socioemotional needs and helped with the acquisition of societal skills. Discussion revolves around the hypothesized differential relations of males and females to families versus same-sex peers.

  11. Sex Typing in Stories and Comprehension, Recall, and Sex Typed Beliefs in Preschool Children.

    Science.gov (United States)

    Quay, Lorene C.; And Others

    This study investigated effects of two story characteristics on preschool boys' and girls' comprehension and recall of stories and their sex-typed beliefs and attitudes. The two story characteristics were the portrayal of the main character as either a male or female and the engagement of the main character in either male or female sex-stereotyped…

  12. Talking about Sex. Growing Pains: Sex Education for Parents. A Newsletter Series. Letter V.

    Science.gov (United States)

    Polulech, Joan Burgess; Nuttall, Paul

    This document presents the fifth of five newsletters on sex education for parents. The newsletters were designed to help parents increase their ability to communicate with their adolescents about sexual issues. They explore the origins of the parents' feelings about sex; teach the importance of a healthy self-concept and how to build it in the…

  13. Sex-Role Orientation and Relationship Development in Same-Sex Dyads.

    Science.gov (United States)

    Lamke, Leanne K.; Bell, Nancy J.

    1982-01-01

    Assessed the relationship between sex-role identity, behavioral interaction, and interpersonal attraction in an initial extended encounter. Female subjects (N=82) identified as either feminine, androgynous, or undifferentiated participated in same-sex dyads. Results of the combined initial and final unstructured interactions indicated greater…

  14. Sexing a sex-role-reversed species based on plumage: potential challenges in the red phalarope

    Directory of Open Access Journals (Sweden)

    Marie-Andrée Giroux

    2016-05-01

    Full Text Available Sex-role reversal, in which males care for offspring, can occur when mate competition is stronger between females than males. Secondary sex traits and mate attracting displays in sex-role-reversed species are usually more pronounced in females than in males. The red phalarope (Phalaropus fulicarius is a textbook example of a sex-role-reversed species. It is generally agreed that males are responsible for all incubation and parental care duties, whereas females typically desert males after having completed a clutch and may pair with new males to lay additional clutches. The breeding plumage of female red phalaropes is usually more brightly colored than male plumage, a reversed sexual dichromatism usually associated with sex-role reversal. Here, we confirm with PCR-based sexing that male red phalaropes can exhibit both the red body plumage typical of a female and the incubation behavior typical of a male. Our result, combined with previous observations of brightly colored red phalaropes incubating nests at the same arctic location (Igloolik Island, Nunavut, Canada, suggests that plumage dichromatism alone may not be sufficient to distinguish males from females in this breeding population of red phalaropes. This stresses the need for more systematic genetic sexing combined with standardized description of intersexual differences in red phalarope plumages. Determining whether such female-like plumage on males is a result of phenotypic plasticity or genetic variation could contribute to further understanding sex-role reversal strategies in the short Arctic summer.

  15. Counselors' Attitudes toward Domestic Violence in Same-Sex versus Opposite-Sex Relationships

    Science.gov (United States)

    Banks, Jamye R.; Fedewa, Alicia L.

    2012-01-01

    Domestic violence is often perceived to occur only in heterosexual relationships. However, domestic violence is also prevalent in same-sex relationships. The majority of the research indicates that counselors perceive same-sex domestic violence differently than heterosexual domestic violence. This literature review synthesizes the research…

  16. "Bareback" pornography consumption and safe-sex intentions of men having sex with men

    NARCIS (Netherlands)

    Jonas, K.J.; Hawk, S.T.; Vastenburg, D.; de Groot, P.

    2014-01-01

    Men having sex with men (MSM) commonly consume "bareback" pornography, which includes scenes of unprotected anal intercourse. Prior research on human imitative behavior suggests that these media might counteract efforts to promote safe-sex behaviors. To date, no studies have demonstrated a causal li

  17. Sex Differences in the Pharmacokinetics of Antidepressants : Influence of Female Sex Hormones and Oral Contraceptives

    NARCIS (Netherlands)

    Damoiseaux, Valerie A.; Proost, Johannes H.; Jiawan, Vincent C. R.; Melgert, Barbro N.

    Women are twice as likely to develop depression as men. Moreover, the symptoms they experience also show sex differences: women tend to develop depression at an earlier age and show more severe symptoms than men. Likewise, the response to antidepressant pharmacotherapy appears to have sex

  18. Well-Being among Same-Sex-and Opposite-Sex-Attracted Youth at School

    Science.gov (United States)

    Rivers, Ian; Noret, Nathalie

    2008-01-01

    In this study, 53 students who reported being solely or primarily attracted to members of the same sex were matched with 53 peers who reported being attracted solely to members of the opposite sex on various demographic factors as well as exposure to bullying at school. Data relating to tobacco and alcohol use, drug use, health risk behaviors,…

  19. Sex Stereotyping in Math Doesn't Add Up. Project on Sex Stereotyping in Education.

    Science.gov (United States)

    Georgia State Univ., Atlanta.

    This instructional module on sex stereotyping and its effect on mathematics education is composed of four transparency masters, two handouts, and a bibliography and is designed to accompany a 25-minute tape. The four transparencies are stereotyping sample mathematics problems, sex differences in mathematical skills, and mathematics courses and job…

  20. Criminalization, legalization or decriminalization of sex work: what female sex workers say in San Francisco, USA.

    Science.gov (United States)

    Lutnick, Alexandra; Cohan, Deborah

    2009-11-01

    Sex work is a criminal offence in San Francisco, USA, and sex work advocates have so far unsuccessfully campaigned for decriminalizing it. Some groups argue that the decriminalization movement does not represent the voices of marginalized sex workers. Using qualitative and quantitative data from the Sex Worker Environmental Assessment Team Study, we investigated the perspectives and experiences of a range of female sex workers regarding the legal status of sex work and the impact of criminal law on their work experiences. Forty women were enrolled in the qualitative phase in 2004 and 247 women in the quantitative phase in 2006-07. Overall, the women in this study seemed to prefer a hybrid of legalization and decriminalization. The majority voiced a preference for removing statutes that criminalize sex work in order to facilitate a social and political environment where they had legal rights and could seek help when they were victims of violence. Advocacy groups need to explore the compromises sex workers are willing to make to ensure safe working conditions and the same legal protections afforded to other workers, and with those who are most marginalized to better understand their immediate needs and how these can be met through decriminalization.

  1. Teacher/Student Classroom Interaction in Vocational Education. A Sex Bias/Sex Stereotyping Project.

    Science.gov (United States)

    Omvig, Clayton P.

    A study examined teacher-student interaction in Kentucky's secondary and postsecondary vocational education classrooms. It investigated whether sex bias or inequities were present and what might explain such differences. A literature review focused on studies conducted at different grade levels with relation to sex bias and classroom interactions.…

  2. Sex Differences in the Pharmacokinetics of Antidepressants : Influence of Female Sex Hormones and Oral Contraceptives

    NARCIS (Netherlands)

    Damoiseaux, Valerie A.; Proost, Johannes H.; Jiawan, Vincent C. R.; Melgert, Barbro N.

    2014-01-01

    Women are twice as likely to develop depression as men. Moreover, the symptoms they experience also show sex differences: women tend to develop depression at an earlier age and show more severe symptoms than men. Likewise, the response to antidepressant pharmacotherapy appears to have sex difference

  3. Sex workers, unite! (Litigating for sex workers' freedom of association in Russia).

    Science.gov (United States)

    Arps, F S E Freddie; Golichenko, Mikhail

    2014-12-11

    The existing legal framework in Russia makes sex work and related activities punishable offenses, leaving sex workers stigmatized, vulnerable to violence, and disproportionally affected by HIV and other sexually transmitted infections. In 2013, the Ministry of Justice, supported by the courts, refused registration and official recognition to the first all-Russia association of sex workers, referring to the fact that sex work is under administrative and criminal punitive bans and therefore the right of association for sex workers is unjustified. In light of international human rights standards, in particular the jurisprudence of the European Court of Human Rights, we examine in this paper whether the overall punitive legal ban on sex work in Russia is discriminatory. The government's positive obligations concerning discrimination against sex workers whose activities are consensual and between adults, and whose working conditions leave them among society's most vulnerable, should outweigh their punitive laws and policies around sex work. The scope of legal criminalization is narrow: it should apply only in exceptional cases where it is clearly justified. Copyright © 2014 Arps and Golichenko. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.

  4. Faceless sex: glory holes and sexual assemblages.

    Science.gov (United States)

    Holmes, Dave; O'Byrne, Patrick; Murray, Stuart J

    2010-10-01

    According to our previous research, the use of glory holes in public venues such as saunas and bathhouses is very popular. The popularity of glory holes is due in part to the anonymous sex that these architectural elements allow. This post-structuralist theoretical reflection seeks to understand the specific nature of anonymous public sex among bathhouse patrons, focusing on the links between desire-architecture-place-sexual practices. Drawing on interviews with glory hole users gathered during an ethnographic research project in bathhouses, this essay goes beyond traditional public health discourse to offer an original perspective on anonymous public sex. Utilizing the philosophy of Deleuze and Guattari's concepts of assemblages and machines, we re-theorize glory hole sex--what we call 'faceless sex'--and rethink the ways that desire is imbricated with our understanding of architecture, place, and public. Finally, we reflect upon the particular ethical challenges that are posed by these particular sexual practices, and ask whether a post-structuralist ethic might be possible.

  5. Teaching safe sex practices to psychiatric patients.

    Science.gov (United States)

    Sladyk, K

    1990-03-01

    An occupational therapist presented her 45-minute program called AIDS Education and Safe Sex 5 times to female mental patients in the locked ward of Cedarcrest Regional Hospital in Newington, Connecticut, to inform them about safe-sex practices and AIDS. She first administered a pretest then spoke briefly about AIDS and safe-sex practices. The lecture emphasized various important points such as no cure for AIDS exist, casual contact (e.g., kiss on the cheek, handshake) cannot transmit HIV, and effectiveness of using latex condoms. The occupational therapist spent much of her time addressing myths about AIDS and what safe-sex practices are. The patients discussed sexual abuse and dishonest partners. She administered a posttest which was the same as the pretest. Some sessions attracted more people than did other sessions. Test scores increased for every patient and for every session. They ranged from a 5% (68-73%) increase for the 3rd session to a 24% (67-91%) increase for the last session. She was not able to determine, however, whether the increased knowledge would translate into positive behavioral changes. Patients' psychiatric symptoms may have interfered with learning resulting in less than ideal improvements in knowledge. These symptoms were hypomanic behavior, restlessness, and distractibility. Perhaps other sessions with experiential techniques (e.g., putting condoms on dummies) would increase their understanding. This program helps fill the information gap not provided by the mass media which avoid mentioning safe-sex practices.

  6. Sex and gender differences in clinical medicine.

    Science.gov (United States)

    Regitz-Zagrosek, Vera; Seeland, Ute

    2012-01-01

    Sex and gender differences in frequent diseases are more widespread than one may assume. In addition, they have significant yet frequently underestimated consequences on the daily practice of medicine, on outcomes and effects of therapies. Gender medicine is a novel medical discipline that takes into account the effects of sex and gender on the health of women and men. The major goal is to improve health and health care for both, for women as well as for men. We give in this chapter an overview on sex and gender differences in a number of clinical areas, in cardiovascular diseases, pulmonary diseases, gastroenterology and hepatology, in nephrology, autoimmune diseases, endocrinology, hematology, neurology. We discuss the preferential use of male animals in drug development, the underrepresentation of women in early and cardiovascular clinical trials, sex and gender differences in pharmacology, in pharmacokinetics and pharmacodynamics, in management and drug use. Most guidelines do not include even well-known sex and gender differences. European guidelines for the management of cardiovascular diseases in pregnancy have only recently been published. Personalized medicine cannot replace gender-based medicine. Large databases reveal that gender remains an independent risk factor after ethnicity, age, comorbidities, and scored risk factors have been taken into account. Some genetic variants carry a different risk in women and men. The sociocultural dimension of gender integrating lifestyle, environment, stress, and other variables cannot be replaced by a sum of biological parameters. Because of this prominent role of gender, clinical care algorithms must include gender-based assessment.

  7. Brain size, sex, and the aging brain.

    Science.gov (United States)

    Jäncke, Lutz; Mérillat, Susan; Liem, Franziskus; Hänggi, Jürgen

    2015-01-01

    This study was conducted to examine the statistical influence of brain size on cortical, subcortical, and cerebellar compartmental volumes. This brain size influence was especially studied to delineate interactions with Sex and Age. Here, we studied 856 healthy subjects of which 533 are classified as young and 323 as old. Using an automated segmentation procedure cortical (gray and white matter [GM and WM] including the corpus callosum), cerebellar (GM and WM), and subcortical (thalamus, putamen, pallidum, caudatus, hippocampus, amygdala, and accumbens) volumes were measured and subjected to statistical analyses. These analyses revealed that brain size and age exert substantial statistical influences on nearly all compartmental volumes. Analyzing the raw compartmental volumes replicated the frequently reported Sex differences in compartmental volumes with men showing larger volumes. However, when statistically controlling for brain size Sex differences and Sex × Age interactions practically disappear. Thus, brain size is more important than Sex in explaining interindividual differences in compartmental volumes. The influence of brain size is discussed in the context of an allometric scaling of the compartmental volumes.

  8. B chromosomes and sex in animals.

    Science.gov (United States)

    Camacho, J P M; Schmid, M; Cabrero, J

    2011-01-01

    Supernumerary (B) chromosomes are dispensable elements found in many eukaryote genomes in addition to standard (A) chromosomes. In many respects, B chromosomes resemble sex chromosomes, so that a common ancestry for them has frequently been suggested. For instance, B chromosomes in grasshoppers, and other insects, show a pycnotic cycle of condensation-decondensation during meiosis remarkably similar to that of the X chromosome. In some cases, B chromosome size is even very similar to that of the X chromosome. These resemblances have led to suggest the X as the B ancestor in many cases. In addition, sex chromosome origin from B chromosomes has also been suggested. In this article, we review the existing evidence for both evolutionary pathways, as well as sex differences for B frequency at adult and embryo progeny levels, B chromosome effects or B chromosome transmission. In addition, we review cases found in the literature showing sex-ratio distortion associated with B chromosome presence, the most extreme case being the paternal sex ratio (PSR) chromosomes in some Hymenoptera. We finally analyse the possibility of B chromosome regularisation within the host genome and, as a consequence of it, whether B chromosomes can become regular members of the host genome.

  9. Molecular mechanisms of sex determination in reptiles.

    Science.gov (United States)

    Rhen, T; Schroeder, A

    2010-01-01

    Charles Darwin first provided a lucid explanation of how gender differences evolve nearly 140 years ago. Yet, a disconnect remains between his theory of sexual selection and the mechanisms that underlie the development of males and females. In particular, comparisons between representatives of different phyla (i.e., flies and mice) reveal distinct genetic mechanisms for sexual differentiation. Such differences are hard to comprehend unless we study organisms that bridge the phylogenetic gap. Analysis of variation within monophyletic groups (i.e., amniotes) is just as important if we hope to elucidate the evolution of mechanisms underlying sexual differentiation. Here we review the molecular, cellular, morphological, and physiological changes associated with sex determination in reptiles. Most research on the molecular biology of sex determination in reptiles describes expression patterns for orthologs of mammalian sex-determining genes. Many of these genes have evolutionarily conserved expression profiles (i.e., DMRT1 and SOX9 are expressed at a higher level in developing testes vs. developing ovaries in all species), which suggests functional conservation. However, expression profiling alone does not test gene function and will not identify novel sex-determining genes or gene interactions. For that reason, we provide a prospectus on various techniques that promise to reveal new sex-determining genes and regulatory interactions among these genes. We offer specific examples of novel candidate genes and a new signaling pathway in support of these techniques.

  10. Comprehensive Care Model for Sex Trafficking Survivors.

    Science.gov (United States)

    Twigg, Naomi M

    2017-05-01

    The purpose of this study was to identify aftercare services for domestic minor of sex trafficking (DMST) survivors provided by U.S. residential treatment centers. A qualitative research study was conducted with aftercare program personnel from five U.S. residential treatment centers for DMST survivors. Interviews were conducted with staff from five different residential treatment centers providing services exclusively to domestic minor sex trafficking survivors. Participants described the range of services offered to address survivors' posttrafficking needs. Participants' responses assisted in expanding an existing care model to include education re-entry, family reunification, family reconciliation, and emergency substance use services. This study led to the refinement of an aftercare service delivery model and laid the foundation to develop best practice guidelines for providing aftercare services to DMST survivors. Sex trafficking is a global health problem affecting our youth today. Nurses have a vital role in combatting sex trafficking by raising awareness about the problem and restoring the lives of sex trafficking victims by implementing innovative care programs. © 2017 Sigma Theta Tau International.

  11. Sex determination using the Probabilistic Sex Diagnosis (DSP: Diagnose Sexuelle Probabiliste) tool in a virtual environment.

    Science.gov (United States)

    Chapman, Tara; Lefevre, Philippe; Semal, Patrick; Moiseev, Fedor; Sholukha, Victor; Louryan, Stéphane; Rooze, Marcel; Van Sint Jan, Serge

    2014-01-01

    The hip bone is one of the most reliable indicators of sex in the human body due to the fact it is the most dimorphic bone. Probabilistic Sex Diagnosis (DSP: Diagnose Sexuelle Probabiliste) developed by Murail et al., in 2005, is a sex determination method based on a worldwide hip bone metrical database. Sex is determined by comparing specific measurements taken from each specimen using sliding callipers and computing the probability of specimens being female or male. In forensic science it is sometimes not possible to sex a body due to corpse decay or injury. Skeletalization and dissection of a body is a laborious process and desecrates the body. There were two aims to this study. The first aim was to examine the accuracy of the DSP method in comparison with a current visual sexing method on sex determination. A further aim was to see if it was possible to virtually utilise the DSP method on both the hip bone and the pelvic girdle in order to utilise this method for forensic sciences. For the first part of the study, forty-nine dry hip bones of unknown sex were obtained from the Body Donation Programme of the Université Libre de Bruxelles (ULB). A comparison was made between DSP analysis and visual sexing on dry bone by two researchers. CT scans of bones were then analysed to obtain three-dimensional (3D) virtual models and the method of DSP was analysed virtually by importing the models into a customised software programme called lhpFusionBox which was developed at ULB. The software enables DSP distances to be measured via virtually-palpated bony landmarks. There was found to be 100% agreement of sex between the manual and virtual DSP method. The second part of the study aimed to further validate the method by analysing thirty-nine supplementary pelvic girdles of known sex blind. There was found to be a 100% accuracy rate further demonstrating that the virtual DSP method is robust. Statistically significant differences were found in the identification of sex

  12. Criminal Profiles of Violent Juvenile Sex and Violent Juvenile Non-Sex Offenders: An Explorative Longitudinal Study

    Science.gov (United States)

    van Wijk, Anton Ph.; Mali, Bas R. F.; Bullens, Ruud A. R.; Vermeiren, Robert R.

    2007-01-01

    Few studies have longitudinally investigated the criminal profiles of violent juvenile sex and violent juvenile non-sex offenders. To make up for this lack, this study used police records of juveniles to determine the nature of the criminal profiles of violent sex offenders (n = 226) and violent non-sex offenders (n = 4,130). All offenders…

  13. 34 CFR 403.13 - What are the personnel requirements regarding the elimination of sex discrimination and sex...

    Science.gov (United States)

    2010-07-01

    ... elimination of sex discrimination and sex stereotyping? 403.13 Section 403.13 Education Regulations of the... Planning Responsibilities? § 403.13 What are the personnel requirements regarding the elimination of sex discrimination and sex stereotyping? (a) A State that desires to participate in the State Vocational and Applied...

  14. Sexual selection and the evolution of obligatory sex.

    Science.gov (United States)

    Hadany, Lilach; Beker, Tuvik

    2007-12-20

    Among the long-standing conundrums of evolutionary theory, obligatory sex is one of the hardest. Current theory suggests multiple factors that might explain the benefits of sex when compared with complete asexuality, but no satisfactory explanation for the prevalence of obligatory sex in the face of facultative sexual reproduction. We show that when sexual selection is present obligatory sex can evolve and be maintained even against facultative sex, under common scenarios of deleterious mutations and environmental changes.

  15. Demographic and genetic consequences of disturbed sex determination.

    OpenAIRE

    Wedekind, C

    2017-01-01

    During sex determination, genetic and/or environmental factors determine the cascade of processes of gonad development. Many organisms, therefore, have a developmental window in which their sex determination can be sensitive to, for example, unusual temperatures or chemical pollutants. Disturbed environments can distort population sex ratios and may even cause sex reversal in species with genetic sex determination. The resulting genotype-phenotype mismatches can have long-lasting effects on p...

  16. CEE/CA: Report calls for decriminalization of sex work.

    Science.gov (United States)

    Betteridge, Glenn

    2006-04-01

    In December 2005, the Central and Eastern European Harm Reduction Network (CEEHRN) released a report calling for the decriminalization of sex work in the 27 countries of Central and Eastern Europe and Central Asia (CEE/CA). The report brings together a wealth of published and original information concerning sex work, laws regulating sex work, epidemiological data regarding HIV and other sexually transmitted infections (STIs), services available to sex workers, and human rights abuses faced by sex workers.

  17. The influence of same-sex marriage on the understanding of same-sex relationships.

    Science.gov (United States)

    Lannutti, Pamela J

    2007-01-01

    This study examines the ways in which legally recognized same-sex marriage affects the understanding of same-sex romantic relationships for lesbian, gay, bisexual and transgendered (LGBT) individuals. Participants (N = 288) responded to an open-ended Web-based survey asking them to describe how legally recognized same-sex marriage influenced their view of their own romantic relationship or romantic relationships in general. Results indicate that legally recognized same-sex marriage impacted participants' understanding of romantic relationships by making existing relationships seem more real and by serving as a tool through which participants realized their desires for ideal potential partner and relationship characteristics. The results suggest that legally recognized same-sex marriage is seen as both beneficial and challenging for samesex couples.

  18. Sex-related gene and sex identification of Crested Ibis Nipponia nippon (Ciconiiformes: Threskiornithidae)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Crested Ibis (Nipponia nippon) is a critical endangeredspecies of the world. At present, a reintroduction program will be conducted to save this species essentially. However, because the Crested Ibise is a sexual alike bird, it is very difficult to identify the sex from the morphological character. In order to identify the sex easily and select the right individuals for captive breeding and reintroduction, the sex related gene on W chromosome was amplified and the sex of three Crested Ibises were also identified in the present study. The 262bp fragment was also sequenced, and we found that there were 13 different nucleotide sites with 2.25 of transition/transversion based on the comparison with that of the Oriental White Stork. The sequence will also provide a theoretic base for further designing specific primer for sex related gene in the Crested Ibis.

  19. Sex bias in psychoactive drug advertisements.

    Science.gov (United States)

    King, E

    1980-05-01

    A recent concern has been the possible effect of sex-role stereotypes upon physicians' prescription patterns. In an attempt to examine the part played by drug advertisements, this paper will present a content analysis of psychoactive (mood-modifying) drug ads appearing in the American Journal of Psychiatry over a 17-year period; and a study of subjects' perceptions of the patients depicted in these drug ads across eight dimensions emerging from the content analysis. An initial perusal of psychoactive drug ads in professional medical journals suggested the existence of a sex bias: Females appeared to be presented as patients more often than males, and in a much more demeaning manner. The present analyses were done in an attempt to discover if a sex bias does exist in drug advertisements, which may influence the physician's perception of his or her patients, and subsequently, his or her prescription patterns.

  20. Sex-Related Differences in GI Disorders.

    Science.gov (United States)

    Prusator, Dawn K; Chang, Lin

    2017-02-24

    Epidemiological studies indicate sex-related differences among functional gastrointestinal disorders (FGIDs) wherein females are more likely to receive a diagnosis than their male counterparts. However, the mechanism by which females exhibit an increased vulnerability for development of these pathophysiologies remains largely unknown, and therapeutic treatments are limited. The current chapter focuses on clinical research outlining our current knowledge of factors that contribute to the female predominance among FGID patients such as the menstrual cycle and sex hormones. In addition, we will discuss progress in preclinical research, including animal models, which serve as valuable tools for the investigation of the development and long term manifestation of symptoms observed within the patient population. Although much progress has been made, additional longitudinal studies in both clinical and preclinical research are necessary to identify more specific mechanisms underlying sex-related differences in FGIDs as well as targets for improved therapeutic approaches.