scholarly journals Critical role of quorum sensing-dependent glutamate metabolism in homeostatic osmolality and outer membrane vesiculation in Burkholderia glumae

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Yongsung Kang ◽  
Eunhye Goo ◽  
Jinwoo Kim ◽  
Ingyu Hwang
Keyword(s):  
Quorum Sensing ◽  
Outer Membrane ◽  
Critical Role ◽  
Glutamate Metabolism ◽  
Burkholderia Glumae ◽  
Membrane Vesiculation

scholarly journals Contribution of the Periplasmic Chaperone Skp to Efficient Presentation of the Autotransporter IcsA on the Surface of Shigella flexneri

2008 ◽  
Vol 191 (3) ◽  
pp. 815-821 ◽  
Author(s):  
Jennifer K. Wagner ◽  
Jason E. Heindl ◽  
Andrew N. Gray ◽  
Sumita Jain ◽  
Marcia B. Goldberg
Keyword(s):  
Outer Membrane ◽  
Shigella Flexneri ◽  
Critical Role ◽  
Amino Terminus ◽  
Primary Role ◽  
Membrane Anchor ◽  
Bacterial Surface ◽  
Periplasmic Chaperone ◽  
Cell Spread

ABSTRACT IcsA is an outer membrane protein in the autotransporter family that is required for Shigella flexneri pathogenesis. Following its secretion through the Sec translocon, IcsA is incorporated into the outer membrane in a process that depends on YaeT, a component of an outer membrane β-barrel insertion machinery. We investigated the role of the periplasmic chaperone Skp in IcsA maturation. Skp is required for the presentation of the mature amino terminus (alpha-domain) of IcsA on the bacterial surface and contributes to cell-to-cell spread of S. flexneri in cell culture. A mutation in skp does not prevent the insertion of the β-barrel into the outer membrane, suggesting that the primary role of Skp is the folding of the IcsA alpha-domain. In addition, the requirement for skp can be partially bypassed by disrupting icsP, an ortholog of Escherichia coli ompT, which encodes the protease that processes IcsA between the mature amino terminus and the β-barrel outer membrane anchor. These findings are consistent with a model in which Skp plays a critical role in the chaperoning of the alpha-domain of IcsA during transit through the periplasm.

scholarly journals Tuning of Differential Lipid Order Between Submicrometric Domains and Surrounding Membrane Upon Erythrocyte Reshaping

2018 ◽  
Vol 48 (6) ◽  
pp. 2563-2582 ◽  
Author(s):  
Catherine Leonard ◽  
Hélène Pollet ◽  
Christiane Vermylen ◽  
Nir Gov ◽  
Donatienne Tyteca ◽  
...  
Keyword(s):  
Critical Role ◽  
Lipid Domains ◽  
Generalized Polarization ◽  
Lipid Order ◽  
Imaging Mode ◽  
Erythrocyte Deformation ◽  
Membrane Vesiculation ◽  
The Difference ◽  
Surrounding Membrane

Background/Aims: Transient nanometric cholesterol- and sphingolipid-enriched domains, called rafts, are characterized by higher lipid order as compared to surrounding lipids. Here, we asked whether the seminal concept of highly ordered rafts could be refined with the presence of lipid domains exhibiting different enrichment in cholesterol and sphingomyelin and association with erythrocyte curvature areas. We also investigated how differences in lipid order between domains and surrounding membrane (bulk) are regulated and whether changes in order differences could participate to erythrocyte deformation and vesiculation. Methods: We used the fluorescent hydration- and membrane packing-sensitive probe Laurdan to determine by imaging mode the Generalized Polarization (GP) values of lipid domains vs the surrounding membrane. Results: Laurdan revealed the majority of sphingomyelin-enriched domains associated to low erythrocyte curvature areas and part of the cholesterol-enriched domains associated with high curvature. Both lipid domains were less ordered than the surrounding lipids in erythrocytes at resting state. Upon erythrocyte deformation (elliptocytes and stimulation of calcium exchanges) or membrane vesiculation (storage at 4°C), lipid domains became more ordered than the bulk. Upon aging and in membrane fragility diseases (spherocytosis), an increase in the difference of lipid order between domains and the surrounding lipids contributed to the initiation of domain vesiculation. Conclusion: The critical role of domain-bulk differential lipid order modulation for erythrocyte reshaping is discussed in relation with the pressure exerted by the cytoskeleton on the membrane.

The role of glia in late-life depression

2012 ◽  
Vol 24 (12) ◽  
pp. 1878-1890 ◽  
Author(s):  
Matt Bennett Paradise ◽  
Sharon Linda Naismith ◽  
Louisa Margaret Norrie ◽  
Manuel Benedikt Graeber ◽  
Ian Bernard Hickie
Keyword(s):  
Microglial Activation ◽  
Gray Matter Volume ◽  
Critical Role ◽  
Late Life ◽  
Glutamate Metabolism ◽  
Late Life Depression ◽  
Subcortical Structures ◽  
Age Dependent ◽  
The Brain

ABSTRACTLate-life depression (LLD) has a complex and multifactoral etiology. There is growing interest in elucidating how glia, acting alone or as part of a glial–neuronal network, may contribute to the pathophysiology of depression. In this paper, we explore results from neuroimaging studies showing gray-matter volume loss in key frontal and subcortical structures implicated in LLD, and present the few histological studies that have examined neuronal and glial densities in these regions. Compared to results in younger people with depression, there appear to be age-dependent differences in neuronal pathology but the changes in glial pathology may be more subtle, perhaps reflecting a longer-term compensatory gliosis to earlier damage. We then consider the mechanisms by which both astrocytes and microglia may mediate and modulate neuronal dysfunction and possible degeneration in depression. These include a critical role in the response to peripheral inflammation and central microglial activation, as well as a key role in glutamate metabolism. Advances in our understanding of glia are highlighted, including the role of microglia as “electricians” of the brain and astrocytes as key communicating cells, an integral part of the tripartite synapse. Finally, implications for clinicians are discussed, including the consideration of glia as biomarkers for LLD and incorporation of glia into future therapeutic strategies.

The Role of the SLP in Autism Spectrum Disorder Screening and Assessment

2008 ◽  
Vol 15 (2) ◽  
pp. 50-59 ◽  
Author(s):  
Amy Philofsky
Keyword(s):  
Language Development ◽  
Critical Role ◽  
Children With Autism ◽  
Autism Spectrum ◽  
Children With Asd ◽  
Prevalence Estimates ◽  
Notable Increase ◽  
Screening Assessment ◽  
Critical Components

AbstractRecent prevalence estimates for autism have been alarming as a function of the notable increase. Speech-language pathologists play a critical role in screening, assessment and intervention for children with autism. This article reviews signs that may be indicative of autism at different stages of language development, and discusses the importance of several psychometric properties—sensitivity and specificity—in utilizing screening measures for children with autism. Critical components of assessment for children with autism are reviewed. This article concludes with examples of intervention targets for children with ASD at various levels of language development.

A critical role of iNOS-derived Nitric Oxide (NO) and progesterone in implantation

1998 ◽  
Vol 5 (1) ◽  
pp. 115A-115A
Author(s):  
K CHWALISZ ◽  
E WINTERHAGER ◽  
T THIENEL ◽  
R GARFIELD
Keyword(s):  
Nitric Oxide ◽  
Critical Role
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