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Apical microvilli

Klaus Deckmann, Wolfgang Kummer
A peculiar cell type of the respiratory and gastrointestinal epithelia, originally termed "brush cell" or "tuft cell" by electron microscopists because of its apical tuft of microvilli, utilizes the canonical bitter taste transduction cascade known from oropharyngeal taste buds to detect potential hazardous compounds, e.g. bacterial products. Upon stimulation, this cell initiates protective reflexes and local inflammatory responses through release of acetylcholine and chemokines. Guided by the understanding of these cells as sentinels, they have been newly discovered at previously unrecognized anatomical locations, including the urethra...
September 29, 2016: Histochemistry and Cell Biology
Joni Leppänen, Olli Helminen, Heikki Huhta, Joonas H Kauppila, Ilkka Miinalainen, Veli-Pekka Ronkainen, Juha Saarnio, Petri P Lehenkari, Tuomo J Karttunen
Doublecortin-like kinase 1 (DCLK1) is a microtubule-associated kinase. In murine intestine, DCLK1 marks tuft cells with characteristic microvilli, features of neuroendocrine cells and also quiescent stem cell-like properties. The occurrence and pathological role of DCLK1-positive cells in human intestinal mucosa is unknown. We analysed DCLK1 expression in healthy duodenal, jejunal and colorectal mucosa samples (n = 35), and in duodenal specimens from patients with coeliac disease (n = 20). The samples were immunohistochemically double-stained with DCLK1, and synaptophysin, chromogranin A and Ki-67...
November 2016: APMIS: Acta Pathologica, Microbiologica, et Immunologica Scandinavica
Meredith L Weck, Scott W Crawley, Colin R Stone, Matthew J Tyska
Transporting epithelial cells interact with the luminal environment using a tightly packed array of microvilli known as the brush border. During intestinal epithelial differentiation, microvillar packing and organization are driven by cadherin-dependent adhesion complexes that localize to the distal tips of microvilli, where they drive physical interactions between neighboring protrusions. Although enrichment of the "intermicrovillar adhesion complex" (IMAC) at distal tips is required for proper function, the mechanism driving tip accumulation of these factors remains unclear...
September 15, 2016: Current Biology: CB
Basile Tarchini, Abigail L D Tadenev, Nicholas Devanney, Michel Cayouette
Sensory perception in the inner ear relies on the hair bundle, the highly polarized brush of movement detectors crowning hair cells. We previously showed that, in the mouse cochlea, the edge of the forming bundle is defined by the 'bare zone', a microvilli-free sub-region of apical membrane specified by the mInsc-LGN-Gαi protein complex. We now report that LGN and Gαi also occupy the very tip of stereocilia that directly abut the bare zone. We demonstrate that LGN and Gαi are both essential to promote the elongation and differential identity of stereocilia across rows...
September 22, 2016: Development
Robin A Felder, Pedro A Jose, Peng Xu, John J Gildea
The sodium bicarbonate cotransporter (NBCe2, aka NBC4) was originally isolated from the human testis and heart (Pushkin et al. IUBMB Life 50:13-19, 2000). Subsequently, NBCe2 was found in diverse locations where it plays a role in regulating sodium and bicarbonate transport, influencing intracellular, extracellular, interstitial, and ultimately plasma pH (Boron et al. J Exp Biol. 212:1697-1706, 2009; Parker and Boron, Physiol Rev. 93:803-959, 2013; Romero et al. Mol Asp Med. 34:159-182, 2013). NBCe2 is located in human and rodent renal-collecting duct and proximal tubule...
September 2016: Current Hypertension Reports
James T Hentig, Christine A Byrd-Jacobs
Zinc sulfate is a known olfactory toxicant, although its specific effects on the olfactory epithelium of zebrafish are unknown. Olfactory organs of adult zebrafish were exposed to zinc sulfate and, after 2, 3, 5, 7, 10 or 14 days, fish were processed for histological, immunohistochemical, ultrastructural, and behavioral analyses. Severe morphological disruption of the olfactory organ was observed two days following zinc sulfate exposure, including fusion of lamellae, epithelial inflammation, and significant loss of anti-calretinin labeling...
2016: International Journal of Molecular Sciences
Chao-Kai Kang, Chia-Shian Lin, Yao-Chung Hu, Shu-Chuan Tsai, Tsung-Han Lee
Milkfish, a species within the primitive teleost lineage Otocephala, can survive in water conditions ranging from hypo- to hyper-saline. This study explored the effects of environmental salinity on apical morphologies of ionocytes and the expression of villin homologs in the gills of milkfish acclimated to either seawater (SW) or fresh water (FW). Scanning electron microscopy revealed that the ionocytes in the gill filaments of SW and FW milkfish, respectively, cellular apical morphologies were hole-type and squint-type...
August 21, 2016: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Claudemir Kuhn Faccioli, Renata Alari Chedid, Ricardo Hideo Mori, Antônio Carlos do Amaral, Irene Bastos Franceschini-Vicentini, Carlos Alberto Vicentini
This cytochemical study investigated the acid and alkaline phosphatase of the digestive tract of Hemisorubim platyrhynchos. Acid phosphatase was detected in the lining epithelium throughout the digestive tract, whereas alkaline phosphatase was only observed in the intestine. In the esophagus, an acid phosphatase reaction occurred in the apical cytoplasm of the epithelial cells and was related to epithelial protection and freeing of superficial cells for sloughing. Similar results were also observed in epithelial cells of gastric epithelium...
August 7, 2016: Acta Histochemica
Carolyn M Ott
Tethered midbody remnants dancing across apical microvilli, encountering the centrosome, and beckoning forth a cilium-who would have guessed this is how polarized epithelial cells coordinate the end of mitosis and the beginning of ciliogenesis? New evidence from Bernabé-Rubio et al. (2016. J. Cell Biol supports this emerging model.
August 1, 2016: Journal of Cell Biology
Yichao Li, Robert N Fariss, Jennifer W Qian, Ethan D Cohen, Haohua Qian
PURPOSE: We examined if light induces changes in the retinal structure that can be observed using optical coherence tomography (OCT). METHODS: Normal C57BL/6J mice (age 3-6 months) adapted to either room light (15 minutes to ∼5 hours, 50-500 lux) or darkness (overnight) were imaged using a Bioptigen UHR-OCT system. Confocal histologic images were obtained from mice killed under light- or dark-adapted conditions. RESULTS: The OCT image of eyes adapted to room light exhibited significant increases (6...
July 1, 2016: Investigative Ophthalmology & Visual Science
Natalie Porat-Shliom, Amber J Tietgens, Christina M Van Itallie, Lynn Vitale-Cross, Michal Jarnik, Olivia J Harding, James M Anderson, J Silvio Gutkind, Roberto Weigert, Irwin M Arias
UNLABELLED: Liver kinase B1 (LKB1) and its downstream effector AMP-activated protein kinase (AMPK) play critical roles in polarity establishment by regulating membrane trafficking and energy metabolism. In collagen sandwich-cultured hepatocytes, loss of LKB1 or AMPK impaired apical ABCB11 (Bsep) trafficking and bile canalicular formation. In the present study, we used liver-specific (albumin-Cre) LKB1 knockout mice (LKB1(-/-) ) to investigate the role of LKB1 in the maintenance of functional tight junction (TJ) in vivo...
October 2016: Hepatology: Official Journal of the American Association for the Study of Liver Diseases
Verena Untiet, Lisa M Moeller, Ximena Ibarra-Soria, Gabriela Sánchez-Andrade, Miriam Stricker, Eva M Neuhaus, Darren W Logan, Thomas Gensch, Marc Spehr
In rodents, the vomeronasal system controls social and sexual behavior. However, several mechanistic aspects of sensory signaling in the vomeronasal organ remain unclear. Here, we investigate the biophysical basis of a recently proposed vomeronasal signal transduction component-a Ca(2+)-activated Cl(-) current. As the physiological role of such a current is a direct function of the Cl(-) equilibrium potential, we determined the intracellular Cl(-) concentration in dendritic knobs of vomeronasal neurons. Quantitative fluorescence lifetime imaging of a Cl(-)-sensitive dye at the apical surface of the intact vomeronasal neuroepithelium revealed increased cytosolic Cl(-) levels in dendritic knobs, a substantially lower Cl(-) concentration in vomeronasal sustentacular cells, and an apparent Cl(-) gradient in vomeronasal neurons along their dendritic apicobasal axis...
October 2016: Chemical Senses
Young K Kim, Daniel G Blackburn
In eggs of oviparous reptiles, fetal membranes maintain developing embryos through the exchange of respiratory gases and provision of water and calcium. As part of a survey of reptilian fetal membranes, we used scanning electron microscopy to study fetal membrane morphology in the oviparous Pueblan milksnake, Lampropeltis triangulum campbelli. The chorioallantois initially is an avascular structure lined by enlarged chorionic and allantoic epithelia. Upon vascularization, the chorionic epithelium becomes greatly attenuated, enhancing the potential for gas exchange; the allantoic epithelium also flattens...
July 2016: Journal of Experimental Zoology. Part B, Molecular and Developmental Evolution
R Dallai, D Mercati, Y Mashimo, R Machida, R G Beutel
The rectal pads of a species of the controversial polyneopteran order Zoraptera were examined using histological sections and TEM micrographs. Six pads are present along the thin rectal epithelium. Each pad consists of a few large principal cells surrounded by flattened junctional cells, which extend also beneath the principal cells. The cells are lined by a thin apical cuticle. No basal cells and no cavity have been observed beneath the pad. Principal cells have a regular layer of apical microvilli and are joined by intercellular septate junctions, which are interrupted by short dilatations of the intercellular space...
July 2016: Arthropod Structure & Development
Yvan Campos, Xiaohui Qiu, Elida Gomero, Randall Wakefield, Linda Horner, Wojciech Brutkowski, Young-Goo Han, David Solecki, Sharon Frase, Antonella Bongiovanni, Alessandra d'Azzo
Maintenance of epithelial cell polarity and epithelial barrier relies on the spatial organization of the actin cytoskeleton and proper positioning/assembly of intercellular junctions. However, how these processes are regulated is poorly understood. Here we reveal a key role for the multifunctional protein Alix in both processes. In a knockout mouse model of Alix, we identified overt structural changes in the epithelium of the choroid plexus and in the ependyma, such as asymmetrical cell shape and size, misplacement and abnormal beating of cilia, blebbing of the microvilli...
2016: Nature Communications
Hanen Boukedi, Sameh Sellami, Sonia Ktari, Najeh Belguith-Ben Hassan, Tahya Sellami-Boudawara, Slim Tounsi, Lobna Abdelkefi-Mesrati
Insecticides derived from Bacillus thuringiensis are gaining worldwide importance as environmentally desirable alternatives to chemicals for the control of pests in public health and agriculture. Isolation and characterization of new strains with higher and broader spectrum of activity is an ever growing field. In the present work, a novel Tunisian B. thuringiensis isolate named BLB459 was characterized and electrophoresis assay showed that among a collection of 200 B. thuringiensis strains, the plasmid profile of BLB459 was distinctive...
May 2016: Microbiological Research
Ichha Khanal, Ahmed Elbediwy, Maria Del Carmen Diaz de la Loza, Georgina C Fletcher, Barry J Thompson
In epithelial tissues, polarisation of microtubules and actin microvilli occurs along the apical-basal axis of each cell, yet how these cytoskeletal polarisation events are coordinated remains unclear. Here, we examine the hierarchy of events during cytoskeletal polarisation in Drosophila melanogaster epithelia. Core apical-basal polarity determinants polarise the spectrin cytoskeleton to recruit the microtubule-binding proteins Patronin (CAMSAP1, CAMSAP2 and CAMPSAP3 in humans) and Shortstop [Shot; MACF1 and BPAG1 (also known as DST) in humans] to the apical membrane domain...
July 1, 2016: Journal of Cell Science
Chun-hong Bai, Xin-long Ma
OBJECTIVE: To observe the ultrastructural change of the route of gut bacterial translocation in a rat with spinal cord injury (SCI). METHODS: Forty Wistar rats were divided into the following groups: control group and 3 SCI groups (10 in each group). The rats in the SCI groups were established SCI model at 24 h, 48 h, and 72 h after SCI. Small intestine mucous membrane tissue was identified and assayed by transmission electron microscope, scanning electron microscope and immunofluorescence microscopy...
November 2015: Chinese Journal of Applied Physiology
Samson N Dowland, Romanthi J Madawala, Connie E Poon, Laura A Lindsay, Christopher R Murphy
In preparation for uterine receptivity, the uterine epithelial cells (UECs) exhibit a loss of microvilli and glycocalyx and a restructuring of the actin cytoskeleton. The prominin-1 protein contains large, heavily glycosylated extracellular loops and is usually restricted to apical plasma membrane (APM) protrusions. The present study examined rat UECs during early pregnancy using immunofluorescence, western blotting and deglycosylation analyses. Ovariectomised rats were injected with oestrogen and progesterone to examine how these hormones affect prominin-1...
May 11, 2016: Reproduction, Fertility, and Development
M Y Waqas, P Yang, N Ahmed, Q Zhang, T Liu, Q Li, L Hu, C Hong, Q Chen
In poultry, the infundibulum is the place of fertilization, eggshell production, and sperm storage, while its uterovaginal junction (UVJ) is regarded as the most important site, which has abundant sperm storage tubules (SST). We examined the ultrastructure of the epithelium with relation to its unique secretory cytology in the UVJ of hens using transmission electron microscopy. The epithelium of the UVJ is lined with ciliated and secretory cells. Ciliated cells are characterized with light and dense secretory granules in supernuclear cytoplasm...
September 1, 2016: Poultry Science
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