scholarly journals Characterization of the Flagellar Collar Reveals Structural Plasticity Essential for Spirochete Motility

mBio ◽  
2021 ◽  
Author(s):  
Yunjie Chang ◽  
Hui Xu ◽  
Md A. Motaleb ◽  
Jun Liu
Keyword(s):  
Structural Plasticity ◽  
Human Diseases ◽  
Distinct Morphology

Many spirochetes cause serious human diseases. They are well recognized by their distinct morphology and motility.

scholarly journals Characterization of the flagellar collar reveals structural plasticity essential for spirochete motility

2021 ◽  
Author(s):  
Yunjie Chang ◽  
Hui Xu ◽  
Md A. Motaleb ◽  
Jun Liu
Keyword(s):  
Electron Tomography ◽  
Structural Plasticity ◽  
Connective Tissues ◽  
Flagellar Motors ◽  
Specific Complex ◽  
Periplasmic Flagella ◽  
Curved Membrane ◽  
Distinct Morphology

AbstractSpirochetes are a remarkable group of bacteria with distinct morphology and periplasmic flagella that enable motility in viscous environments, such as host connective tissues. The collar, a spirochete-specific complex of the periplasmic flagellum, is required for the unique spirochete motility, yet it has not been clear how the collar assembles and enables spirochetes to transit between complex host environments. Here, we characterize the collar complex in the Lyme disease spirochete Borrelia burgdorferi. We discover as well as delineate the distinct functions of two novel collar proteins, FlcB and FlcC, by combining subtractive bioinformatic, genetic, and cryo-electron tomography approaches. Our high-resolution in-situ structures reveal that the multi-protein collar has a remarkable structural plasticity essential not only for assembly of flagellar motors in the highly curved membrane of spirochetes but also for generation of the high torque necessary for spirochete motility.

A MORPHOMETRIC SYSTEM FOR DESCRIBING THE MICROMORPHOLOGY OF ORGANIC SOILS AND ORGANIC LAYERS: FURTHER QUANTITATIVE AND QUALITATIVE CHARACTERIZATION

1985 ◽  
Vol 65 (4) ◽  
pp. 695-706 ◽  
Author(s):  
C. A. FOX
Keyword(s):  
Thin Section ◽  
Quantitative Information ◽  
Level Of Detail ◽  
Organic Soils ◽  
Organic Layer ◽  
Qualitative Information ◽  
Organic Layers ◽  
Level Ii ◽  
Distinct Morphology

At the first level of detail of description of a thin section, qualitative information about the occurrence of the fabric zones (regions of distinct morphology) and their basic morphologic units (the various components) were recorded with symbols in a fabric description symbol. At a second level of detail of description, Level II, additional quantitative and qualitative micromorphological information can be included with coding into the fabric description symbol according to the following. general format:[Formula: see text]At Level II description, quantitative information on the areal proportions of the fabric zones and basic morphologic units are recorded with indices in the fabric unit; qualitative data on the kind of boundary relationships between adjacent fabric zones, and quantitative data on the areal occurrence of the fabric zones are recorded with the modifier expression; and both quantitative and qualitative information on the occurrence, morphology, and arrangement of specific features observed in the fabric zones are recorded with the fabric unit descriptor. Depending on the requirements of a study, more than one fabric unit descriptor can be written for each fabric zone that is delineated in a thin section. The procedure for writing fabric description symbols at a Level II detail of description of a thin section is presented and applied to the characterization of the micromorphology of an organic layer from a Typic Mesisol. Key words: Micromorphology, descriptive method, organic soils, characterization

scholarly journals Solution NMR characterization of chemokine CXCL8/IL-8 monomer and dimer binding to glycosaminoglycans: structural plasticity mediates differential binding interactions

2015 ◽  
Vol 472 (1) ◽  
pp. 121-133 ◽  
Author(s):  
Prem Raj B. Joseph ◽  
Philip D. Mosier ◽  
Umesh R. Desai ◽  
Krishna Rajarathnam
Keyword(s):  
Structural Plasticity ◽  
Neutrophil Function ◽  
Solution Nmr ◽  
Binding Interactions ◽  
High Affinity ◽  
Nmr Characterization ◽  
Differential Binding

Structural plasticity plays a major role in determining differential binding of CXCL8 monomer and dimer to glycosaminoglycans (GAGs) and that dimer is the high-affinity GAG ligand. We propose that these properties play important roles in orchestrating in vivo chemokine-mediated neutrophil function.

Characterization of a heat-resistant strain of Tilapia ovary cells

1989 ◽  
Vol 92 (3) ◽  
pp. 353-359
Author(s):  
H.C. Wang ◽  
J.D. Chen ◽  
G.C. Li ◽  
F.H. Yew
Keyword(s):  
Heat Treatment ◽  
Cell Cycle ◽  
Heat Shock ◽  
Resistant Strain ◽  
Normal Growth ◽  
Ovary Cells ◽  
Heat Resistant ◽  
Shock Proteins ◽  
Distinct Morphology

Tilapia ovary cells (TO-2) cease to proliferate when moved from normal growth temperature of 31 degrees C to 37 degrees C, and arrest in G1 and G2 phases of the cell cycle. The ability of the arrested cells to re-enter the cell cycle when restored to 31 degrees C decreases inversely with time spent at 37 degrees C. A heat-resistant strain, TO-37c, cloned from the surviving fraction of TO-2 after heat treatment, has been found to re-enter the cell cycle with greater facility and to have a higher rate of survival. TO-37c cells have a smaller cell volume than TO-2 and show a distinct morphology at 37 degrees C. Most of the heat-shock proteins (hsps) induced on temperature change were similar, but in TO-37c the decline in the synthesis of a 27 X 10(3) Mr hsp was faster and a 37 degrees C-specific 60 X 10(3) Mr hsp was missing. Ultraviolet (u.v.) sensitivity was slightly affected if heat treatment was given after irradiation. However, when cells were preheated and then u.v. irradiated, the u.v. sensitivity increased sharply for TO-2 cells but not for TO-37c.

scholarly journals Ropinirole and Pramipexole Promote Structural Plasticity in Human iPSC-Derived Dopaminergic Neurons via BDNF and mTOR Signaling

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Ginetta Collo ◽  
Laura Cavalleri ◽  
Federica Bono ◽  
Cristina Mora ◽  
Stefania Fedele ◽  
...  
Keyword(s):  
Kinase Inhibitors ◽  
Structural Plasticity ◽  
Pharmacological Agents ◽  
Trkb Receptors ◽  
Healthy Donors ◽  
Soma Size ◽  
Culture Effects ◽  
Kinase Phosphorylation ◽  
Human Ipsc

The antiparkinsonian ropinirole and pramipexole are D3 receptor- (D3R-) preferring dopaminergic (DA) agonists used as adjunctive therapeutics for the treatment resistant depression (TRD). While the exact antidepressant mechanism of action remains uncertain, a role for D3R in the restoration of impaired neuroplasticity occurring in TRD has been proposed. Since D3R agonists are highly expressed on DA neurons in humans, we studied the effect of ropinirole and pramipexole on structural plasticity using a translational model of human-inducible pluripotent stem cells (hiPSCs). Two hiPSC clones from healthy donors were differentiated into midbrain DA neurons. Ropinirole and pramipexole produced dose-dependent increases of dendritic arborization and soma size after 3 days of culture, effects antagonized by the selective D3R antagonists SB277011-A and S33084 and by the mTOR pathway kinase inhibitors LY294002 and rapamycin. All treatments were also effective in attenuating the D3R-dependent increase of p70S6-kinase phosphorylation. Immunoneutralisation of BDNF, inhibition of TrkB receptors, and blockade of MEK-ERK signaling likewise prevented ropinirole-induced structural plasticity, suggesting a critical interaction between BDNF and D3R signaling pathways. The highly similar profiles of data acquired with DA neurons derived from two hiPSC clones underpin their reliability for characterization of pharmacological agents acting via dopaminergic mechanisms.

Immunophenotypic Characterization of Canine Nodal T-Zone Lymphoma

2020 ◽  
pp. 030098582097407
Author(s):  
Leah Stein ◽  
Cynthia Bacmeister ◽  
Matti Kiupel
Keyword(s):  
T Cell ◽  
Cell Lymphoma ◽  
Accurate Diagnosis ◽  
Ki67 Index ◽  
Fine Needle Aspirate ◽  
Tissue Architecture ◽  
Immunohistochemical Expression ◽  
Diagnostic Criterion ◽  
Distinct Morphology

T-zone lymphoma (TZL) is an indolent nodal T-cell lymphoma most commonly observed in submandibular lymph nodes in dogs. The diagnosis is based on its distinct morphology and expression of CD3. TZL has been reported to have a low Ki67 index and to lack expression of CD45. The latter feature has been used to diagnose this type of lymphoma via fine needle aspirate and flow cytometry without confirmation of the characteristic tissue architecture. The goal of this study was to characterize the immunophenotype of canine nodal TZL in greater detail. Twenty-seven TZLs were selected based on their characteristic morphology. A tissue microarray was generated, and immunohistochemical expression of CD3, CD5, CD20, CD21, CD25, CD45, Bcl-6, and Ki67 was evaluated. Neoplastic T cells in all cases were positive for CD3, CD5, and CD25, and negative for CD20, CD21, and Bcl-6. Positive labelling for CD45 was detected in 2 of the 27 cases with the remaining 25 cases being negative. All cases had a low Ki67 index with an average index of 19.56%. For the CD45-positive TZLs, clonality of the T-cell antigen receptor gamma gene was confirmed in only one of these cases. The observed immunophenotype of canine TZL is similar to previous publications with the exception that 2 cases expressed CD45. Expression of CD45 in TZLs in this study emphasizes the importance of interpreting immunophenotypic findings in conjunction with histopathology to reach an accurate diagnosis and not to use lack of expression of a particular antigen as the sole diagnostic criterion.

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