Some interface phenomena in parasitic protozoa and platyhelminths

1973 ◽  
Vol 51 (3) ◽  
pp. 367-377 ◽  
Author(s):  
J. D. Smyth
Keyword(s):  
Molecular Mimicry ◽  
Intimate Contact ◽  
Interface Phenomena ◽  
Contact Digestion ◽  
Membrane Contact ◽  
Membrane Type ◽  
Host Parasite ◽  
Type 3

The host–parasite interface is defined broadly as a region of intimate contact between host and parasite surfaces. The limitations of this definition are considered. The difficulties of studying the morphology, ultrastructure, and physiology of this region are discussed. Possible host–parasite interfaces appear to fall (theoretically) into one of the following categories: type 1: membrane-to-membrane; type 2A: cytoplasm-to-membrane; type 2B: membrane-to-cytoplasm; type 3: cytoplasm-to-cytoplasm. Phenomena associated with the interface region are various forms of membrane transport, pinocytosis, excretion, secretion, and membrane (= contact) digestion. The apparent role of the interface in differentiation in the protozoan Gregarina polymorpha and the cestode Echinococcus granulosus are discussed. The immunological significance of intimate contact between host and parasite and the various hypotheses to account for the (apparent) 'molecular mimicry' by the parasite, of host surface antigens, are briefly summarized.

scholarly journals Piezo1 mediates angiogenesis through activation of MT1-MMP signaling

2019 ◽  
Vol 316 (1) ◽  
pp. C92-C103 ◽  
Author(s):  
Hojin Kang ◽  
Zhigang Hong ◽  
Ming Zhong ◽  
Jennifer Klomp ◽  
Kayla J. Bayless ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Matrix Metalloproteinase ◽  
Matrix Metalloproteinase 2 ◽  
Sprouting Angiogenesis ◽  
Sphingosine 1 Phosphate ◽  
Wall Shear ◽  
Membrane Type

Angiogenesis is initiated in response to a variety of external cues, including mechanical and biochemical stimuli; however, the underlying signaling mechanisms remain unclear. Here, we investigated the proangiogenic role of the endothelial mechanosensor Piezo1. Genetic deletion and pharmacological inhibition of Piezo1 reduced endothelial sprouting and lumen formation induced by wall shear stress and proangiogenic mediator sphingosine 1-phosphate, whereas Piezo1 activation by selective Piezo1 activator Yoda1 enhanced sprouting angiogenesis. Similarly to wall shear stress, sphingosine 1-phosphate functioned by activating the Ca2+ gating function of Piezo1, which in turn signaled the activation of the matrix metalloproteinase-2 and membrane type 1 matrix metalloproteinase during sprouting angiogenesis. Studies in mice in which Piezo1 was conditionally deleted in endothelial cells demonstrated the requisite role of sphingosine 1-phosphate-dependent activation of Piezo1 in mediating angiogenesis in vivo. These results taken together suggest that both mechanical and biochemical stimuli trigger Piezo1-mediated Ca2+ influx and thereby activate matrix metalloproteinase-2 and membrane type 1 matrix metalloproteinase and synergistically facilitate sprouting angiogenesis.

Host-parasite relationship between congenitalToxoplasmainfection and mouse brain: role of small vessels

Parasitology ◽  
1995 ◽  
Vol 110 (2) ◽  
pp. 123-127 ◽  
Author(s):  
T. A. Sims ◽  
J. Hay
Keyword(s):  
Mouse Brain ◽  
Inflammatory Cell ◽  
Tissue Cyst ◽  
Intimate Contact ◽  
Small Vessels ◽  
Host Parasite Relationship ◽  
Parasite Relationship ◽  
Perivascular Area ◽  
Host Parasite

SUMMARYSmall vessels showing inflammatory cell infiltrates were invariably observed in the vicinity of intactToxoplasmatissue cysts within the brains of mice congenitally infected with the protozoan. Lymphocytes were observed in intimate contact with the luminal aspect of the endothelium, penetrating into the thickened basal lamina and in the perivascular area, which also contained macrophages and neutrophilic granulocytes. Rarely, lymphocytes were observed attached to the outer membrane of the host neurone which contained aToxoplasmatissue cyst and within the inflammatory infiltrate associated with a disintegrating cyst. An hypothesis is presented which combines these morphological observations to explain the events associated with tissue cyst associated recrudescence of latentToxoplasmainfection in mouse brain.

scholarly journals Evidence for a cooperative role of gelatinase A and membrane type-1 matrix metalloproteinase during Xenopus laevis development

2007 ◽  
Vol 124 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Takashi Hasebe ◽  
Rebecca Hartman ◽  
Liezhen Fu ◽  
Tosikazu Amano ◽  
Yun-Bo Shi
Keyword(s):  
Xenopus Laevis ◽  
Matrix Metalloproteinase ◽  
Gelatinase A ◽  
Membrane Type

scholarly journals Genome Delivery and Ion Channel Properties Are Altered in VP4 Mutants of Poliovirus

2003 ◽  
Vol 77 (9) ◽  
pp. 5266-5274 ◽  
Author(s):  
Pranav Danthi ◽  
Magdalena Tosteson ◽  
Qi-han Li ◽  
Marie Chow
Keyword(s):  
Ion Channels ◽  
Lipid Bilayers ◽  
Conformational Transition ◽  
Channel Structure ◽  
Host Cells ◽  
Lethal Mutant ◽  
Ion Channel Properties ◽  
Type 3

ABSTRACT During entry into host cells, poliovirus undergoes a receptor-mediated conformational transition to form 135S particles with irreversible exposure of VP4 capsid sequences and VP1 N termini. To understand the role of VP4 during virus entry, the fate of VP4 during infection by site-specific mutants at threonine-28 of VP4 (4028T) was compared with that of the parental Mahoney type 1 virus. Three virus mutants were studied: the entry-defective, nonviable mutant 4028T.G and the viable mutants 4028T.S and 4028T.V, in which residue threonine-28 was changed to glycine, serine, and valine, respectively. We show that mutant and wild-type (WT) VP4 proteins are localized to cellular membranes after the 135S conformational transition. Both WT and viable 4028T mutant particles interact with lipid bilayers to form ion channels, whereas the entry-defective 4028T.G particles do not. In addition, the electrical properties of the channels induced by the mutant viruses are different from each other and from those of WT Mahoney and Sabin type 3 viruses. Finally, uncoating and/or cytoplasmic delivery of the viral genome is altered in the 4028T mutants: the 4028T.G lethal mutant does not release its genome into the cytoplasm, and genome delivery is slower during infection by mutant 4028T.V 135S particles than by mutant 4028T.S or WT 135S particles. The distinctive electrical characteristics of the different 4028T mutant channels indicate that VP4 sequences might form part of the channel structure. The different entry phenotypes of these VP4 mutants suggest that the ion channels may be related to VP4's role during genome uncoating and/or delivery.

scholarly journals Role of type 1 and type 3 fimbriae in Klebsiella pneumoniae biofilm formation

2010 ◽  
Vol 10 (1) ◽  
pp. 179 ◽  
Author(s):  
Casper Schroll ◽  
Kim B Barken ◽  
Karen A Krogfelt ◽  
Carsten Struve
Keyword(s):  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Type 3

scholarly journals Conversion of Stationary to Invasive Tumor Initiating Cells (TICs): Role of Hypoxia in Membrane Type 1-Matrix Metalloproteinase (MT1-MMP) Trafficking

PLoS ONE ◽  
2012 ◽  
Vol 7 (6) ◽  
pp. e38403 ◽  
Author(s):  
Jian Li ◽  
Stanley Zucker ◽  
Ashleigh Pulkoski-Gross ◽  
Cem Kuscu ◽  
Mihriban Karaayvaz ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Tumor Initiating Cells ◽  
Invasive Tumor ◽  
Membrane Type

scholarly journals Selective function-blocking monoclonal human antibody highlights the important role of membrane type-1 matrix metalloproteinase (MT1-MMP) in metastasis

Oncotarget ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 2781-2799 ◽  
Author(s):  
Albert G. Remacle ◽  
Piotr Cieplak ◽  
Dong Hyun Nam ◽  
Sergey A. Shiryaev ◽  
Xin Ge ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Human Antibody ◽  
Membrane Type

scholarly journals The Expanding Role of MT1-MMP in Cancer Progression

2019 ◽  
Vol 12 (2) ◽  
pp. 77 ◽  
Author(s):  
Anna M. Knapinska ◽  
Gregg B. Fields
Keyword(s):  
Transcription Factor ◽  
Immune Responses ◽  
Cancer Progression ◽  
Negative Regulator ◽  
Fibrillar Collagen ◽  
Biological Functions ◽  
Complete Mapping ◽  
Membrane Type

For over 20 years, membrane type 1 matrix metalloproteinase (MT1-MMP) has been recognized as a key component in cancer progression. Initially, the primary roles assigned to MT1-MMP were the activation of proMMP-2 and degradation of fibrillar collagen. Proteomics has revealed a great array of MT1-MMP substrates, and MT1-MMP selective inhibitors have allowed for a more complete mapping of MT1-MMP biological functions. MT1-MMP has extensive sheddase activities, is both a positive and negative regulator of angiogenesis, can act intracellularly and as a transcription factor, and modulates immune responses. We presently examine the multi-faceted role of MT1-MMP in cancer, with a consideration of how the diversity of MT1-MMP behaviors impacts the application of MT1-MMP inhibitors.

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