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The effects of the deletion of VDAC on the physical properties and proteome of the mitochondrial outer membrane in Neurospora crassaMotnenko, Anna 21 August 2014 (has links)
Mitochondria are essential organelles in the cell. They are enveloped by a two membrane system, an inner and outer membrane. Residing in the outer membrane is the voltage-dependant anion-selective channel (VDAC) which is in very high abundance in the outer membrane. Previously, when VDAC was deleted in N. crassa the mitochondria developed unusual morphology and the fungus became temperature sensitive. This was suspected to be caused by alterations in the membrane architecture. It was found that deletion of VDAC causes a reduction in mitochondrial outer membrane fluidity leading to a fragile outer membrane. In the current study it was also found that loss of VDAC significantly impacts the mitochondrial proteome. These results taken together suggest that VDAC is not only a channel for traversing the outer membrane but appears to be important for the structural integrity of the mitochondria. / October 2014
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Regulace fyzikálních vlastností cytoplazmatické membrány u Bacillus subtilis / Cytoplasmic membrane of Bacillus subtilis Regulation of the physical parametersBeranová, Jana January 2011 (has links)
Bacillus subtilis, a model Gram-positive soil bacterium, employs two distinct mechanisms in its membrane adaptation to low temperature: 1) Long-term adaptation to suboptimal temperature is accomplished by increasing the ratio of anteiso- to iso-branched fatty acids in the membrane lipids. 2) After a sudden temperature decrease, the oxygen-dependent fatty acid desaturase (Des) is induced which desaturates fatty-acyl chains incorporated in membrane lipids. The transcription of the gene encoding desaturase, des, is activated by the decrease of the membrane order, via two- component system DesK-DesR. In this work, I studied the influence of cultivation conditions on the mechanisms of B. subtilis membrane adjustments for a low temperature employing fatty acid analysis, fluorescence spectroscopy, differential scanning calorimetry and methods of molecular biology. In the first part of this work, I examined the impact of the cultivation medium on the composition and biophysical features of the B. subtilis cytoplasmic membrane during growth under the optimal (40 řC) and suboptimal (20 řC) cultivation temperature. I compared the nutrient-rich complex medium containing glucose and the mineral medium supplemented with either glucose or glycerol. The results obtained showed the crucial importance of medium...
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„Gender fluidity“: Die Identitätskrise als Aufbrechen der Geschlechterrollen in Annemarie Schwarzenbachs 'Flucht nach oben'Bachmann, Nadine January 2009 (has links)
The Swiss author Annemarie Schwarzenbach created literary figures that resist being
classified according to a gender binary and heterosexual norm. She thereby, already in the 1930s, imagined something akin to the recent investigative work by Lisa Diamond on gender and sexual fluidity. Schwarzenbach's texts are populated by feminine men and masculine women, a genderswitching that can be interpreted as breaking apart the categories of gender and sexuality. In her
novel Flucht nach oben (1933), in which the dichotomy of male and female is proven invalid, gender role models become obsolete, leading to the protagonist's deep uncertainty about his identity. Schwarzenbach’s characters can thus be called “multi–sexual” as they meld both
genders as well as homo– and hetero–sexual orientations, thereby exceeding culturally fixed borders. The dichotomy between male and female becomes ever more instable, just as the labels hetero–, homo– and bisexual fall apart. In the end of the novel, the main protagonist forms a queer family together with other characters who do not fit into cultural gender norms.
In contrast to earlier studies which interpret Schwarzenbach's texts biographically, I seek to use Diamond’s contemporary model indebted to queer studies. I involve, moreover, theories
by Joan Rivière, René Girard, Eve Sedgwick, and Judith Butler. In addition, Flucht nach oben is read alongside Schwarzenbach's other novels – Freunde um Bernhard (1931), Lyrische Novelle (1933) and Eine Frau zu sehen (1929). These works serve as intertexts that contribute to a deeper
understanding of the recurring character types and constellations of relationships in
Schwarzenbach’s oeuvre.
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„Gender fluidity“: Die Identitätskrise als Aufbrechen der Geschlechterrollen in Annemarie Schwarzenbachs 'Flucht nach oben'Bachmann, Nadine January 2009 (has links)
The Swiss author Annemarie Schwarzenbach created literary figures that resist being
classified according to a gender binary and heterosexual norm. She thereby, already in the 1930s, imagined something akin to the recent investigative work by Lisa Diamond on gender and sexual fluidity. Schwarzenbach's texts are populated by feminine men and masculine women, a genderswitching that can be interpreted as breaking apart the categories of gender and sexuality. In her
novel Flucht nach oben (1933), in which the dichotomy of male and female is proven invalid, gender role models become obsolete, leading to the protagonist's deep uncertainty about his identity. Schwarzenbach’s characters can thus be called “multi–sexual” as they meld both
genders as well as homo– and hetero–sexual orientations, thereby exceeding culturally fixed borders. The dichotomy between male and female becomes ever more instable, just as the labels hetero–, homo– and bisexual fall apart. In the end of the novel, the main protagonist forms a queer family together with other characters who do not fit into cultural gender norms.
In contrast to earlier studies which interpret Schwarzenbach's texts biographically, I seek to use Diamond’s contemporary model indebted to queer studies. I involve, moreover, theories
by Joan Rivière, René Girard, Eve Sedgwick, and Judith Butler. In addition, Flucht nach oben is read alongside Schwarzenbach's other novels – Freunde um Bernhard (1931), Lyrische Novelle (1933) and Eine Frau zu sehen (1929). These works serve as intertexts that contribute to a deeper
understanding of the recurring character types and constellations of relationships in
Schwarzenbach’s oeuvre.
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Alkyllsophospholipid analogues as antileishmanial agentsLux, Henning January 1997 (has links)
No description available.
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Cell membrane dynamics and signal transduction in human ageingNoble, Jane Mary January 2000 (has links)
No description available.
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A mathematical model of interstitial transport and microvascular exchangeTaylor, David G. January 1990 (has links)
A generalized mathematical model is developed to describe the transport of fluid and plasma proteins or other macromolecules within the interstitium. To account for the effects of plasma protein exclusion and interstitial swelling, the interstitium is treated as a multiphase deformable porous medium. Fluid flow is assumed proportional to the gradient in fluid chemical potential and therefore depends not only on the local hydrostatic pressure but also on the local plasma protein concentrations through appropriate colloid osmotic pressure relationships. Plasma protein
transport is assumed to occur by restricted convection, molecular diffusion, and convective dispersion.
A simplified version of the model is used to investigate microvascular exchange of fluid and a single 'aggregate' plasma protein species in mesenteric tissue. The interstitium is approximated by a rigid, rectangular, porous slab displaying two fluid pathways, only one of which is available to plasma proteins.
The model is first used to explore the effects the interstitial plasma protein diffusivity, the tissue hydraulic conductivity, the restricted convection of plasma proteins, and the mesothelial transport characteristics have on the steady-state distribution and transport of plasma proteins and flow of fluid in the tissue. The simulations predict significant convective plasma protein transport and complex fluid flow patterns within the interstitium. These flow patterns can produce local regions of high fluid and plasma protein exchange along the mesothelium which might be erroneously identified as 'leaky sites'. Further, the model predicts significant interstitial osmotic gradients in some instances, suggesting that the Darcy expression invoked in a number of previous models appearing in the literature, in which fluid flow is assumed to be driven by hydrostatic pressure gradients alone, may be inadequate.
Subsequent transient simulations of hypoproteinemia within the model tissue indicate that the interstitial plasma protein content decreases following this upset. The simulations therefore support (qualitatively, at least) clinical observations of hypoproteinemia. Simulations of venous congestion, however, demonstrate that changes in the interstitial plasma protein content following this upset depends, in part, on the relative sieving properties of the filtering and draining vessels. For example, when the reflection coefficients of these two sets of boundaries are similar, the interstitial plasma protein content increases with time due to an increased plasma protein exchange rate across the filtering boundaries and sieving of interstitial plasma proteins at the draining boundaries. (This effect is supported by the clinical observation that interstitial plasma protein content in liver increases during venous congestion.) As the reflection coefficient of the draining boundaries decreases relative to that of the filtering boundaries, there is a net loss of plasma proteins from the interstitium, resulting in a decrease in the total interstitial plasma protein content over time (i.e., the familiar 'plasma protein washout'). Further, the model predicts increased fluid transfer from the interstitium to the peritoneum during venous congestion, supporting the clinical observation of ascites.
Finally, the model is used to study the effects of interstitial plasma protein convection and diffusion, plasma protein exclusion, and the capillary transport properties on the transit times of two macromolecular tracers representative of albumin and γ-globulin within a hypothetical, one-dimensional tissue. As was expected, the transit times of each of the tracers through the model tissue varied inversely with the degree of convective transport. Increasing the interstitial diffusivity of the albumin tracer also led to a moderate decrease in the transit time for that tracer. The capillary wall transport properties, meanwhile, had only a marginal effect on the transit time for the range of capillary permeabilities and reflection coefficients considered. However, these properties (and, in particular, the reflection coefficient) had a more pronounced effect on the ultimate steady-state concentration of the tracer in the outlet stream.
It was the interstitial distribution volume of a given tracer that had the greatest impact on the time required for the outlet tracer concentration to reach 50 % of its steady-state value. This was attributed to the increased filling times associated with larger interstitial distribution volumes. These findings suggest that the 'gel chromatographic effect' observed in some tissues could possibly be explained on the basis of varying distribution volumes. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate
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Intergenerational mobility in contemporary China, 1996-2006Chen, Meng January 2012 (has links)
This thesis aims at systematically investigating intergenerational class mobility in contemporary China between 1996 and 2006, a period of time that largely overlaps the third decade of the country’s reform era. The study seeks answers to the following questions: 1) to what extent Chinese are found in class positions that differ from their class origins; 2) whether the amount of intergenerational mobility increased during the decade in question; 3) whether China has become a more equal society in terms of social mobility; 4) what are the overall patterns of social fluidity in China; and, 5) how mobility outcomes are affected by work-life mobility and various demographic and socioeconomic characteristics, such as gender and the household registration (hukou) background.This research uses nationally representative survey data from three surveys – the Life Histories and Social Change Survey (1996) and the Chinese General Social Surveys (CGSS 2005 and CGSS 2006). I adopt the class structural approach and the EGP (Erikson-Goldthorpe-Protocarero) class schema. Various statistical methods are employed to explore the above issues: descriptive analysis for changes of China’s class structure, absolute rates of mobility and work-life mobility from the first job class to class of destination; log-linear and log-multiplicative analysis for trends and between-group differences in relative mobility; the Hauser-type density levels model and the core model of social fluidity for patterns of social fluidity; and the Stereotype Ordinal Regression Model for multivariate analysis of mobility outcomes. During the decade, China has become a more ‘mobile’ society in an upgraded structural context. While the relative size of the agricultural sector contracted substantially, there is a significant increase in the non-agricultural ‘room’ for occupational attainment, especially in the routine non-manual class and manual working classes. However, the analysis of relative mobility shows that the significant increase in total mobility and upward mobility has resulted mainly from structural changes. Between 1996 and 2006, the origin-destination association net of structural effects has been largely stable. Hence, the study provides little evidence in support of a more equal Chinese society. As regards gender differences, Chinese women are less socially mobile than men, and their mobility outcomes tend to be more affected than men by their social origin.In fitting the density levels model and the core model of social fluidity to the pooled data, I show that the highest likelihood of occurrence lies with the self-inheritance of peasants as well as small business owners. In contrast, mobility between the agricultural sector and non-manual classes displays the lowest likelihood of occurrence. While relative chances of mobility for both men and women are heavily affected the boundary between agricultural and non-agricultural sectors, women are further subject to the hierarchical effect that hinders long-range mobility. In the final part of the empirical analyses, I reveal the decisive role that the first job class plays in mobility processes in China. The results of the multivariate analysis also indicate that the institutional barriers imposed by the hukou system have a striking negative effect on mobility chances.
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Angiotensin II and Related Peptides Alter Liposomal Membrane FluidityBrailoiu, Eugen, Margineanu, Anca, Miyamoto, Michael D. 01 January 1998 (has links)
We investigated the effects of angiotensinogen (Ang), angiotensin I (Ang I), and angiotensin II (Ang II) on the fluidity of phosphatidylcholine vesicles. Changes in fluidity were assessed by changes in anisotopy values calculated from fluorescence polarization measurements. All three compounds produced an increase in membrane fluidity when localized inside the phosphatidylcholine vesicles. When placed outside the vesicles. Ang II increased bilayer rigidity (decreased fluidity), whereas Ang and Ang I produced no effect. These results suggest the possibility that these peptides may alter the fluidity of cell membranes by a direct action on the phospholipid bilayer, which may in turn interfere with receptor-mediated effects.
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Bud-Sex: Sexual Flexibility Among Rural White Straight Men Who Have Sex With MenSilva, Tony 11 January 2019 (has links)
I interviewed 60 rural, white, straight-identified men who have sex with men (MSM). I did so to answer three main research questions: How do rural, white, straight MSM understand their gender and sexual identity? How do their experiences with sexual flexibility relate to the ways in which they understand their gender and sexual identity? How do whiteness and rurality shape how they understand their gender and sexual identity? While participants shared a diversity of experiences, all aligned themselves with straight culture. Participants had varying levels of attractions to women and different sexual histories, but all identified as straight. Sexual identities are not simply descriptors for sexual orientation. They also indicate feelings of belonging in certain communities and cultures, and not belonging in others. My research shows that rural straight MSM are not closeted gay or bisexual men. They are straight men who occasionally enjoy sex with other men. Their narratives, I argue, highlight the difference between sexual orientation, sexual identity, and sexual culture. The ways participants had sex with other men—what I call bud-sex—both reinforced and reflected their alignment with straight culture.
Enjoyment of straight culture, I argue, is the main reason the men I interviewed in this study identified as straight. None of them considered sex with men an important aspect of their identity. “Straight” was an identity that encompassed participants’ alignment with mainstream heterosexual institutions, such as marriage, and straight communities, to which they and most people they knew belonged. Collectively, these institutions and communities comprise straight culture. Participants considered straightness an identity, a way of life, and/or a community. Having sex with men was largely irrelevant to their sexual identity and how they understood their masculinity. Talking to them highlights how straightness is cultivated in a variety of institutions and contexts, and in numerous ways. Because participants grew up in and/or lived in white-majority rural areas, the rural straight culture to which they felt connected was by definition white. Their enjoyment of straight culture—and the institutions, communities, and ways of life attached to it—was central to their identification as straight and masculine. / 2021-01-11
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