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Apical microvilli

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https://www.readbyqxmd.com/read/28636623/the-basolateral-vesicle-sorting-machinery-and-basolateral-proteins-are-recruited-to-the-site-of-enteropathogenic-e-coli-microcolony-growth-at-the-apical-membrane
#1
Gitte A Pedersen, Helene H Jensen, Anne-Sofie B Schelde, Charlotte Toft, Hans N Pedersen, Maj Ulrichsen, Frédéric H Login, Manuel R Amieva, Lene N Nejsum
Foodborne Enteropathogenic Escherichia coli (EPEC) infections of the small intestine cause diarrhea especially in children and are a major cause of childhood death in developing countries. EPEC infects the apical membrane of the epithelium of the small intestine by attaching, effacing the microvilli under the bacteria and then forming microcolonies on the cell surface. We first asked the question where on epithelial cells EPEC attaches and grows. Using models of polarized epithelial monolayers, we evaluated the sites of initial EPEC attachment to the apical membrane and found that EPEC preferentially attached over the cell-cell junctions and formed microcolonies preferentially where three cells come together at tricellular tight junctions...
2017: PloS One
https://www.readbyqxmd.com/read/28596241/disruption-of-rab8a-and-rab11a-causes-formation-of-basolateral-microvilli-in-neonatal-enteropathy
#2
Qiang Feng, Edward M Bonder, Amy C Engevik, Lanjing Zhang, Matthew J Tyska, James R Goldenring, Nan Gao
Misplaced formation of microvilli to basolateral domains and intracellular inclusions in enterocytes are pathognomonic features in congenital enteropathy associated with STX3 mutation. While the demonstrated binding of Myo5b to the Rab8a and Rab11a small GTPases in vitro implicates cytoskeleton-dependent membrane sorting, the mechanisms underlying the microvillar location defect remain unclear. By selective or combinatory disruption of Rab8a and Rab11a membrane traffic in vivo, we demonstrate that transport of distinct cargo to the apical brush-border rely on either individual or both Rab regulators, whereas certain basolateral cargos are redundantly transported by both factors...
June 8, 2017: Journal of Cell Science
https://www.readbyqxmd.com/read/28595928/histopathological-effects-of-cypermethrin-and-bacillus-thuringiensis-var-israelensis-on-midgut-of-chironomus-calligraphus-larvae-diptera-chironomidae
#3
Sabrina Lavarías, Florencia Arrighetti, Augusto Siri
Pesticides are extensively used for the control of agricultural pests and disease vectors, but they also affect non-target organisms. Cypermethrin (CYP) is a synthetic pyrethroid used worldwide. Otherwise, bioinsecticides like Bacillus thuringiensis var. israelensis (Bti) have received great attention as an environmentally benign and desirable alternative. In order to evaluate the toxicity of those pesticides, Chironomus calligraphus was selected due to its high sensitivity to some toxicants. Third and fourth instars larvae were exposed to serial dilutions of CYP and Bti to determine LC50 values...
June 2017: Pesticide Biochemistry and Physiology
https://www.readbyqxmd.com/read/28548701/microtubules-regulate-brush-border-formation
#4
Facundo M Tonucci, Anabela Ferretti, Evangelina Almada, Pamela Cribb, Rodrigo Vena, Florencia Hidalgo, Cristián Favre, Matt J Tyska, Irina Kaverina, M Cecilia Larocca
Most epithelial cells contain apical membrane structures associated to bundles of actin filaments, which constitute the brush border. Whereas microtubule participation in the maintenance of the brush border identity has been characterized, their contribution to de novo microvilli organization remained elusive. Hereby, using a cell model of individual enterocyte polarization, we found that nocodazole induced microtubule depolymerization prevented the de novo brush border formation. Microtubule participation in brush border actin organization was confirmed in polarized kidney tubule MDCK cells...
May 26, 2017: Journal of Cellular Physiology
https://www.readbyqxmd.com/read/28500222/energy-requirements-of-odor-transduction-in-the-chemosensory-cilia-of-olfactory-sensory-neurons-rely-on-oxidative-phosphorylation-and-glycolytic-processing-of-extracellular-glucose
#5
Pablo S Villar, Ricardo Delgado, Cecilia Vergara, Juan G Reyes, Juan Bacigalupo
The mechanisms that power the physiological events occuring in cilia, flagella and microvilli are of fundamental importance for the functions of these important and ubicuous organelles. The olfactory epithelium (OE) is mostly populated by ciliated olfactory sensory neurons (OSNs) and surrounding sustentacular cells (SCs) with apical microvilli. The only OSN dendrite extends to the surface forming a knob projecting several chemosensory cilia of approximately 50 x 0.2 μm, devoid of inner membranes embedded in a mucus layer...
May 12, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28467791/dry-age-related-macular-degeneration-like-pathology-in-aged-5xfad-mice-ultrastructure-and-microarray-analysis
#6
Sung Wook Park, Sora Im, Hyoung Oh Jun, Kihwang Lee, Young-Jun Park, Jin Hyoung Kim, Woo Jin Park, Young-Hoon Lee, Jeong Hun Kim
Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly. The two types of AMD are: dry and wet AMD. While laser-induced choroidal neovascularization has been used extensively in the studies of wet AMD, there is no established mouse model that fully recapitulates the cardinal features of dry AMD. A lack of appropriate mouse model for dry AMD has hampered the translational research on the pathogenesis of the disease and the development of therapeutic agents. We hypothesized that 5XFAD mice, an animal model for the study of Alzheimer's disease, can be used as a mouse model for dry AMD with regard to the amyloid beta (Aβ) related pathology...
June 20, 2017: Oncotarget
https://www.readbyqxmd.com/read/28430576/ezrin-activation-by-lok-phosphorylation-involves-a-pip2-dependent-wedge-mechanism
#7
Thaher Pelaseyed, Cécile Sauvanet, Raghuvir Viswanatha, Joshua J Filter, Michael L Goldberg, Anthony Bretscher
How cells specify morphologically distinct plasma membrane domains is poorly understood. Prior work has shown that restriction of microvilli to the apical aspect of epithelial cells requires the localized activation of the membrane-F-actin linking protein ezrin. Using an in vitro system, we now define a multi-step process whereby the kinase LOK specifically phosphorylates ezrin to activate it. Binding of PIP2 to ezrin induces a conformational change permitting the insertion of the LOK C-terminal domain to wedge apart the membrane and F-actin-binding domains of ezrin...
April 21, 2017: ELife
https://www.readbyqxmd.com/read/28407399/abnormal-rab11-rab8-vesicles-cluster-in-enterocytes-of-patients-with-microvillus-inclusion-disease
#8
Georg F Vogel, Andreas R Janecke, Iris M Krainer, Karin Gutleben, Barbara Witting, Sally G Mitton, Sahar Mansour, Antje Ballauff, Joseph T Roland, Amy C Engevik, Ernest Cutz, Thomas Müller, James R Goldenring, Lukas A Huber, Michael W Hess
Microvillus inclusion disease (MVID) is a congenital enteropathy characterized by accumulation of vesiculo-tubular endomembranes in the subapical cytoplasm of enterocytes, historically termed "secretory granules." However, neither their identity nor pathophysiological significance is well defined. Using immunoelectron microscopy and tomography, we studied biopsies from MVID patients (3× Myosin 5b mutations and 1× Syntaxin3 mutation) and compared them to controls and genome-edited CaCo2 cell models, harboring relevant mutations...
April 13, 2017: Traffic
https://www.readbyqxmd.com/read/28401359/ultrastructure-of-fat-body-cells-and-malpighian-tubule-cells-in-overwintering-scoliopteryx-libatrix-noctuoidea
#9
Saška Lipovšek, Franc Janžekovič, Tone Novak
The herald moths, Scoliopteryx libatrix, overwinter in hypogean habitats. The ultrastructure of their fat body (FB) cells and Malpighian tubule (MT) epithelial cells was studied by light microscopy and transmission electron microscopy, and essential biometric and biochemical measurements were performed. The FB was composed of adipocytes and sparse urocytes. The ultrastructure of both cells did not change considerably during this natural starvation period, except for rough endoplasmic reticulum (rER) which became more abundant in March females...
April 11, 2017: Protoplasma
https://www.readbyqxmd.com/read/28363254/pancreatic-neuroendocrine-carcinoma-with-exocrine-differentiation-in-a-young-cat
#10
Masaki Michishita, Mariko Takagi, Takuya E Kishimoto, Rei Nakahira, Takeshi Nogami, Hisashi Yoshimura, Hitoshi Hatakeyama, Daigo Azakami, Kazuhiko Ochiai, Kimimasa Takahashi
A 35-mo-old spayed female mixed-breed cat with continuous vomiting, emaciation, and abdominal distention for 2 wk was presented to a private veterinary clinic for evaluation. At 71 d after the initial visit, the cat died with anemia, jaundice, and hypoalbuminemia, and was subjected to autopsy. Grossly, numerous firm masses, 0.5-2.5 cm diameter, were randomly located in the left lobe of the pancreas. Histologic examination revealed that the pancreatic mass consisted of 2 tumor cell types: mostly small round cells with a minority of epithelial cells...
March 1, 2017: Journal of Veterinary Diagnostic Investigation
https://www.readbyqxmd.com/read/28265783/t84-monolayers-are-superior-to-caco-2-as-a-model-system-of-colonocytes
#11
Sarah Devriese, Lien Van den Bossche, Sophie Van Welden, Tom Holvoet, Iris Pinheiro, Pieter Hindryckx, Martine De Vos, Debby Laukens
Colonic adenocarcinoma-derived Caco-2 and T84 epithelial cell lines are frequently used as in vitro model systems of functional epithelial barriers. Both are utilised interchangeably despite evidence that differentiated Caco-2 cells are more reminiscent of small intestinal enterocytes than of colonocytes, whereas differentiated T84 cells are less well characterised. The aim of this study was, therefore, to further characterise and compare differentiated Caco-2 and T84 cells. The objectives were to (1) compare the brush border morphology, (2) measure the expression of enterocyte- and colonocyte-specific genes and (3) compare their response to butyrate, which is dependent on the monocarboxylate transporter 1 (MCT1), an apical protein expressed primarily in colonocytes...
March 6, 2017: Histochemistry and Cell Biology
https://www.readbyqxmd.com/read/28264821/role-of-polarity-proteins-in-the-generation-and-organization-of-apical-surface-protrusions
#12
Gerard Apodaca
Protruding from the apical surfaces of epithelial cells are specialized structures, including cilia, microplicae, microvilli, and stereocilia. These contribute to epithelial function by cushioning the apical surface, by amplifying its surface area to facilitate nutrient absorption, and by promoting sensory transduction and barrier function. Despite these important roles, and the diseases that result when their formation is perturbed, there remain significant gaps in our understanding of the biogenesis of apical protrusions, or the pathways that promote their organization and orientation once at the apical surface...
March 6, 2017: Cold Spring Harbor Perspectives in Biology
https://www.readbyqxmd.com/read/28187870/the-unique-organization-of-filamentous-actin-in-the-medullary-canal-of-the-medulla-oblongata
#13
Bai-Hong Tan, Chun-Yan Guo, Tian-Qing Xiong, Ling-Meng Chen, Yan-Chao Li
In the central canal, F-actin is predominantly localized in the apical region, forming a ring-like structure around the circumference of the lumen. However, an exception is found in the medulla oblongata, where the apical F-actin becomes interrupted in the ventral aspect of the canal. To clarify the precise localization of F-actin, the fluorescence signals for F-actin were converted to the peroxidase/DAB reaction products in this study by a phalloidin-based ultrastructural technique, which demonstrated that F-actin is located mainly in the microvilli and terminal webs in the ependymocytes...
April 2017: Tissue & Cell
https://www.readbyqxmd.com/read/28159658/the-rat-vomeronasal-organ-is-a-vitamin-d-target
#14
A Rodewald, V M Gebhart, H Oehring, G F Jirikowski
We studied the expression of vitamin D receptor and of vitamin D binding protein in the rat vomeronasal organ. With immunofluorescence, in situ hybridization and with reverse transcriptase PCR we found both proteins in sensory as well as in non-sensory cells. Sensory neurons contained immunoreactivity for vitamin D3 receptor in nuclei, in portions of the cytoplasm, and in apical dendrites and their microvilli. Vitamin D binding protein was observed in sensory neuron axons and cytoplasm, mostly confined to dendrites...
January 31, 2017: Journal of Chemical Neuroanatomy
https://www.readbyqxmd.com/read/28052271/establishment-and-characterization-of-an-sv40-large-t-antigen-transduced-porcine-colonic-epithelial-cell-line
#15
Bastian Kaiser, Martina Böttner, Thilo Wedel, Ronald M Brunner, Tom Goldammer, Szilvia Lesko, Gotthold Gäbel, Alexander Gleich, Helga Pfannkuche
Continuous cell lines have become indispensable tools that have enabled investigations into cellular mechanisms by increasing experimental reproducibility and sample availability, and decreasing the use of experimental animals. To facilitate studies of epithelial barrier function of the porcine colon, we aimed to establish an epithelial cell line with an extended replicative capacity. Cells were isolated from the proximal colon of a 3-week-old piglet and transduced using a recombinant retroviral vector construct containing the simian virus 40 large T antigen (SV40 TAg)...
2017: Cells, Tissues, Organs
https://www.readbyqxmd.com/read/27882813/dietary-zinc-modifies-diabetic-induced-renal-pathology-in-rats
#16
Wael M Elsaed, Hazem Abdelhamid Mohamed
This study was conducted to investigate how far dietary zinc (Zn) modifies the histomorphological alterations induced by diabetes in rat kidneys. The animals were divided into negative control group (10 rats). Diabetes was induced in thirty animals by streptozotocin. After confirming diabetes, the animals were divided into three groups (n = 10). Group II served as the positive control group (fed on standard diet), group III was fed on Zn deficient diet, and group IV was fed on Zn supplemented diet. Caspase-3 immune staining was used to estimate the caspase activity...
November 2017: Renal Failure
https://www.readbyqxmd.com/read/27859898/structural-and-ultrastructural-features-of-the-malpighian-tubules-of-dolycoris-baccarum-linnaeus-1758-heteroptera-pentatomidae
#17
Nurcan Özyurt, Damla Amutkan, Irmak Polat, Tenay Kocamaz, Selami Candan, Zekiye Suludere
The morphology and ultrastructure of the Malpighian tubules of Dolycoris baccarum were analyzed by scanning (SEM) and transmission (TEM) electron microscopy in order to determine their functional organization. The Malpighian tubules are compared with similar structures of other insects based on cell structure and functional organization. The Malpighian tubules of D. baccarum extend from the midgut-hindgut region of the digestive tract. The Malpighian tubules are divided into two regions: the proximal segment is short and flattened and the distal segment is long, stringy in shape and free in hemolymph...
April 2017: Microscopy Research and Technique
https://www.readbyqxmd.com/read/27856525/microvilli-morphology-can-affect-efflux-active-p-glycoprotein-in-confluent-mdckii-nki_hmdr1-and-caco-2-cell-monolayers
#18
Zhou Meng, Sylvain Le Marchand, Deep Agnani, Matt Szapacs, Harma Ellens, Joe Bentz
From fits of drug transport kinetics across confluent MDCKII-hMDR1-NKI and Caco-2 cell monolayers we estimated the levels of efflux active P-glycoprotein (P-gp) in these two cell lines (companion paper, Meng at el., 2016a). In the present work, we compared the efflux active P-gp number to the total P-gp level, using LC/MSMS, and showed that in Caco-2 cells total P-gp is about 10-fold greater than efflux active P-gp, while in MDCKII-hMDR1-NKI cells these values are within 2-fold. We further visualized the microvilli in MDCKII-hMDR1-NKI and Caco-2 cells using three-dimensional structured illumination super-resolution microscopy and found that the microvilli in Caco-2 cells are taller and more densely packed than those in MDCK-NKI-hMDR1 cells...
November 16, 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/27846033/brush-cells-the-newly-identified-gatekeepers-of-the-urinary-tract
#19
Wolfgang Kummer, Klaus Deckmann
PURPOSE OF REVIEW: A specialized epithelial cell with chemosensory properties of taste cells known from the mouth has been newly identified in the urethra and linked to pathogen recognition. We here describe its properties and its link to defence mechanisms, showing parallels to similar sentinel cells in the respiratory and gastrointestinal tract. RECENT FINDINGS: In the urethra, slender epithelial cells with apical microvilli ('brush cells') express bitter and umami taste receptors and the downstream signalling cascade known from oropharyngeal gustation, utilizing it to monitor for bacterial products and bacterial growth facilitating conditions...
March 2017: Current Opinion in Urology
https://www.readbyqxmd.com/read/27825102/microvillar-injury-in-renal-tubular-epithelial-cells-induced-by-calcium-oxalate-crystal-and-the-protective-role-of-epigallocatechin-3-gallate
#20
Kedsarin Fong-Ngern, Arada Vinaiphat, Visith Thongboonkerd
Pathogenic mechanisms of kidney stone disease remained unclear. This study investigated its initial cellular/molecular mechanisms when calcium oxalate monohydrate (COM) crystal adhered to renal tubular cells. Transmission electron microscopy revealed decreased length and density of microvilli, whereas Western blot analysis showed that whole-cell ezrin (a microvillus-stabilizing protein), not β-actin, was decreased in COM-treated cells. Immunofluorescence staining, followed by laser-scanning confocal microscopy and subcellular fractionations, revealed decreases in both ezrin and F-/β-actin at apical membrane...
January 2017: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
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