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Apical microvilli

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https://www.readbyqxmd.com/read/29109151/peropsin-modulates-transit-of-vitamin-a-from-retina-to-retinal-pigment-epithelium
#1
Jeremy D Cook, Sze Yin Ng, Marcia Lloyd, Shannon Eddington, Hui Sun, Jeremy Nathans, Dean Bok, Roxana A Radu, Gabriel H Travis
Peropsin is a nonvisual opsin in both vertebrate and invertebrate species. In mammals, peropsin is present in the apical microvilli of retinal pigment epithelial (RPE) cells. These structures interdigitate with the outer segments (OS) of rod and cone photoreceptor cells. RPE cells play critical roles in the maintenance of photoreceptors, including the recycling of visual chromophore for the opsin visual pigments. Here, we sought to identify the function of peropsin in the mouse eye. To this end, we generated mice with a null mutation in the peropsin gene (Rrh)...
November 6, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29090441/sublethal-dose-of-deltamethrin-damage-the-midgut-cells-of-the-mayfly-callibaetis-radiatus-ephemeroptera-baetidae
#2
Helen Pinto Santos, Yeisson Gutiérrez, Eugênio Eduardo Oliveira, José Eduardo Serrão
In insects, the midgut performs multiple physiologic functions (e.g., digestion and nutrients absorption) and serves as a physical/chemical barrier against pathogens and chemical stressors such as deltamethrin, a pyrethroid insecticide, commonly used in insect control that are agricultural pests and human disease vectors. Here, we described the midgut cell ultrastructure of Callibaetis radiatus nymphs, which are bioindicators of water quality and the ultrastructural alterations in midgut under sublethal exposure to deltamethrin at three different periods (1, 12, 24 h)...
October 31, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29069081/spatiotemporal-changes-in-the-distribution-of-lhfpl5-in-mice-cochlear-hair-bundles-during-development-and-in-the-absence-of-pcdh15
#3
Shanthini Mahendrasingam, Robert Fettiplace, Kumar N Alagramam, Ellen Cross, David N Furness
Mechanosensory transduction by vertebrate hair cells depends on a protein complex at the tips of shorter stereocilia associated with mechanoelectrical transduction channels activated by tip links in the hair bundle. In mammalian hair cells, this complex includes transmembrane channel-like protein subunit 1 (TMC1), lipoma HMGIC fusion partner-like 5 protein (LHFPL5) and protocadherin 15 (PCDH15), a lower-end component of the tip link. TMC1 interacts with LHFPL5 and PCDH15 but how the complex develops to maturity, and the relationships between these proteins, remains uncertain...
2017: PloS One
https://www.readbyqxmd.com/read/29044184/zebrafish-aversive-taste-co-receptor-is-expressed-in-both-chemo-and-mechanosensory-cells-and-plays-a-role-in-lateral-line-development
#4
Nazia Mojib, Jin Xu, Zinka Bartolek, Barry Imhoff, Nael A McCarty, Chong Hyun Shin, Julia Kubanek
Fishes rely on both chemical and tactile senses to orient themselves to avoid predators, and to detect and taste food. This is likely achieved by highly coordinated reception of signals by mechano- and chemosensory receptors in fish. A small co-receptor from zebrafish, receptor activity modifying protein (RAMP)-like triterpene glycoside receptor (RL-TGR), was previously found to be involved in recognition of triterpene glycosides, a family of naturally occurring compounds that act as chemical defenses in various prey species...
October 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29032203/construction-of-artificial-human-peritoneal-tissue-by-cell-accumulation-technique-and-its-application-for-visualizing-morphological-dynamics-of-cancer-peritoneal-metastasis
#5
Yoshiya Asano, Tadashi Odagiri, Hiroe Oikiri, Michiya Matsusaki, Mitsuru Akashi, Hiroshi Shimoda
Human peritoneum is composed of mesothelial monolayer and stromal tissue containing microvasculature. Dissemination and infiltration of cancer cells to the peritoneum result in cancer peritoneal metastasis which is an important prognostic factor of intraperitoneal or intrapelvic carcinoma. To elucidate an initial metastatic mechanism of cancer cells, in vitro human peritoneal models are demanded. In this study, we created a three-dimensional artificial human peritoneal tissue (AHPT) harboring the blood or lymphatic vascular network by cell-accumulation technique...
October 12, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/29021220/an-apicosome-initiates-self-organizing-morphogenesis-of-human-pluripotent-stem-cells
#6
Kenichiro Taniguchi, Yue Shao, Ryan F Townshend, Chari L Cortez, Clair E Harris, Sasha Meshinchi, Sundeep Kalantry, Jianping Fu, K Sue O'Shea, Deborah L Gumucio
Human pluripotent stem cells (hPSCs) self-organize into apicobasally polarized cysts, reminiscent of the lumenal epiblast stage, providing a model to explore key morphogenic processes in early human embryos. Here, we show that apical polarization begins on the interior of single hPSCs through the dynamic formation of a highly organized perinuclear apicosome structure. The membrane surrounding the apicosome is enriched in apical markers and displays microvilli and a primary cilium; its lumenal space is rich in Ca(2+) Time-lapse imaging of isolated hPSCs reveals that the apicosome forms de novo in interphase, retains its structure during mitosis, is asymmetrically inherited after mitosis, and relocates to the recently formed cytokinetic plane, where it establishes a fully polarized lumen...
October 11, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28962851/steroidal-pheromones-and-their-potential-target-sites-in-the-vomeronasal-organ
#7
Rodewald Andrea, Mills Daniel, M Veronika Gebhart, Gustav F Jirikowski
Steroids are important olfactory signals in most mammalian species. The vomeronasal organ has been suspected to be the primary target of pheromones. In rat vomeronasal sensory neurons express steroid binding proteins and nuclear receptors. Some binding globulins were found also in single ciliated cells of the non-sensory vomeronasal epithelium. Immunoelectron microscopy revealed VDR in olfactory microvilli and DPB in apical membrane protrusions of supporting sells within the sensory epithelium. Pilot behavioral studies with dogs showed increased sniffing duration upon exposure to low concentrations of vitamin D while higher concentrations were less effective...
September 26, 2017: Steroids
https://www.readbyqxmd.com/read/28951331/design-development-and-characterization-of-synthetic-bruch-s-membranes
#8
Denver C Surrao, Ursula Greferath, Yu-Qian Chau, Stuart J Skabo, Mario Huynh, Kinnari J Shelat, Ioannis J Limnios, Erica L Fletcher, Qin Liu
Age-related macular degeneration (AMD) is a leading cause of blindness, and dry AMD has no effective treatment. Retinal constructs comprising retinal pigment epithelium (RPE) cells supported by electrospun scaffolds have been investigated to treat dry AMD. However, electrospun scaffolds studied to-date do not mimic the structural microenvironment of human Bruch's membrane (BM), essential for native-like RPE monolayers. The aim of this study was to develop a structurally biomimetic scaffold designed to support a functional RPE monolayer, comprising porous, electrospun nanofibrous membranes (ENMs), coated with laminin, mimicking the inner collagenous layer (ICL) and basal RPE lamina respectively, the cell supporting layers of the BM...
December 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28905451/gene-edited-human-kidney-organoids-reveal-mechanisms-of-disease-in-podocyte-development
#9
Yong Kyun Kim, Ido Refaeli, Craig R Brooks, Peifeng Jing, Ramila E Gulieva, Michael R Hughes, Nelly M Cruz, Yannan Liu, Angela J Churchill, Yuliang Wang, Hongxia Fu, Jeffrey W Pippin, Lih Y Lin, Stuart J Shankland, A Wayne Vogl, Kelly M McNagny, Benjamin S Freedman
A critical event during kidney organogenesis is the differentiation of podocytes, specialized epithelial cells that filter blood plasma to form urine. Podocytes derived from human pluripotent stem cells (hPSC-podocytes) have recently been generated in nephron-like kidney organoids, but the developmental stage of these cells and their capacity to reveal disease mechanisms remains unclear. Here, we show that hPSC-podocytes phenocopy mammalian podocytes at the capillary loop stage (CLS), recapitulating key features of ultrastructure, gene expression, and mutant phenotype...
September 14, 2017: Stem Cells
https://www.readbyqxmd.com/read/28898451/comparative-ultrastructure-of-coxal-glands-in-unfed-larvae-of-leptotrombidium-orientale-schluger-1948-trombiculidae-and-hydryphantes-ruber-de-geer-1778-hydryphantidae
#10
Andrey B Shatrov
Coxal glands of unfed larvae Leptotrombidium orientale (Schluger, 1948) (Trombiculidae), a terrestrial mite parasitizing vertebrates, and Hydryphantes ruber (de Geer, 1778) (Hydryphantidae), a water mite parasitizing insects were studied using transmission electron microscopy. In both species, the coxal glands are represented by a paired tubular organ extending on the sides of the brain from the mouthparts to the frontal midgut wall and are formed of the cells arranged around the central lumen. As in other Parasitengona, the coxal glands are devoid of a proximal sacculus...
September 12, 2017: Journal of Morphology
https://www.readbyqxmd.com/read/28855375/shear-stress-induces-noncanonical-autophagy-in-intestinal-epithelial-monolayers
#11
Sun Wook Kim, Jonathan Ehrman, Mok-Ryeon Ahn, Jumpei Kondo, Andrea A Mancheno Lopez, Yun Sik Oh, Xander H Kim, Scott W Crawley, James R Goldenring, Matthew J Tyska, Erin C Rericha, Ken S Lau
Flow of fluids through the gut, such as milk from a neonatal diet, generates a shear stress on the unilaminar epithelium lining the lumen. We report that exposure to physiological levels of fluid shear stress leads to the formation of large vacuoles, containing extracellular contents within polarizing intestinal epithelial cell monolayers. These observations lead to two questions: how can cells lacking primary cilia transduce shear stress, and what molecular pathways support the formation of vacuoles that can exceed 80% of the cell volume? We find that shear forces are sensed by actin-rich microvilli that eventually generate the apical brush border, providing evidence that these structures possess mechanosensing ability...
November 1, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28846140/an-examination-of-surface-epithelium-structures-of-the-embryo-across-the-genus-poeciliopsis-poeciliidae
#12
Tami M Panhuis, Megan Fris, Laura Tuhela, Lucia Kwan
In viviparous, teleost fish, with postfertilization maternal nutrient provisioning, embryonic structures that facilitate maternal-fetal nutrient transfer are predicted to be present. For the family Poeciliidae, only a handful of morphological studies have explored these embryonic specializations. Here, we present a comparative morphological study in the viviparous poeciliid genus, Poeciliopsis. Using microscopy techniques, we examine the embryonic surface epidermis of Poeciliopsis species that vary in their level of postfertilization maternal nutrient provisioning and placentation across two phylogenetic clades and three independent evolutionary origins of placentation...
August 28, 2017: Journal of Morphology
https://www.readbyqxmd.com/read/28837408/intestinal-surfactant-permeation-enhancers-and-their-interaction-with-enterocyte-cell-membranes-in-a-mucosal-explant-system
#13
E Michael Danielsen, Gert H Hansen
Intestinal permeation enhancers (PEs) are agents aimed to improve oral delivery of therapeutic drugs with poor bioavailability. The main permeability barrier for oral delivery is the intestinal epithelium, and PEs act to increase the paracellular and/or transcellular passage of drugs. Transcellular passage can be achieved by cell membrane permeabilization and/or by endocytic uptake and subsequent transcytosis. One broad class of PEs is surfactants which act by inserting into the cell membrane, thereby perturbing its integrity, but little is known about how the dynamics of the membrane are affected...
July 3, 2017: Tissue Barriers
https://www.readbyqxmd.com/read/28830330/ultrastructural-alterations-in-thyrocytes-of-zebrafish-danio-rerio-after-exposure-to-propylthiouracil-and-perchlorate
#14
Florian Schmidt, Raoul Wolf, Lisa Baumann, Thomas Braunbeck
Histopathology is a widely used approach to evaluate effects of endocrine-active chemicals in the thyroid. However, effects at an ultrastructural level have hardly been examined in fish thyroids. In the present study, zebrafish was exposed to sublethal concentrations of propylthiouracil (PTU; 0-50 mg/L) and perchlorate (PER; 0-5,000 µg/L) for 5 weeks in a modified early life-stage test. None of the treatments caused significant mortality (no observed effect concentrations for survival ≥50 mg/L [PTU] and ≥5,000 µg/L [PER])...
July 2017: Toxicologic Pathology
https://www.readbyqxmd.com/read/28825699/an-apical-mrck-driven-morphogenetic-pathway-controls-epithelial-polarity
#15
Ceniz Zihni, Evi Vlassaks, Stephen Terry, Jeremy Carlton, Thomas King Chor Leung, Michael Olson, Franck Pichaud, Maria Susana Balda, Karl Matter
Polarized epithelia develop distinct cell surface domains, with the apical membrane acquiring characteristic morphological features such as microvilli. Cell polarization is driven by polarity determinants including the evolutionarily conserved partitioning-defective (PAR) proteins that are separated into distinct cortical domains. PAR protein segregation is thought to be a consequence of asymmetric actomyosin contractions. The mechanism of activation of apically polarized actomyosin contractility is unknown...
September 2017: Nature Cell Biology
https://www.readbyqxmd.com/read/28815590/juxtanodin-in-retinal-pigment-epithelial-cells-expression-and-biological-activities-in-regulating-cell-morphology-and-actin-cytoskeleton-organization
#16
Fengyi Liang, Ji Hyun Hwang, Nicholas Weiwei Tang, Walter Hunziker
Juxtanodin (also known as ermin) was initially identified as an actin cytoskeleton-related oligodendroglial protein in the rat central nervous system. It was subsequently also found in the rat olfactory neuroepithelium, especially at the apical junctional belt of the sustentacular cells. We further examined juxtanodin expression and functional roles in the retina using fluorescence histochemistry, confocal microscopy, immuno-electron microscopy, molecular biology and cell culture. Prominent juxtanodin expression was found in the photoreceptor-supporting retinal pigment epithelium (RPE), especially in a zone corresponding to the apices of RPE cells, at the roots of the RPE microvilli, and at the base of RPE cells next to the Bruch's membrane...
August 17, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28789587/light-on-a-sensory-interface-linking-the-cerebrospinal-fluid-to-motor-circuits-in-vertebrates
#17
Lydia Djenoune, Claire Wyart
The cerebrospinal fluid (CSF) is circulating around the entire central nervous system (CNS). The main function of the CSF has been thought to insure the global homeostasis of the CNS. Recent evidence indicates that the CSF also dynamically conveys signals modulating the development and the activity of the nervous system. The later observation implies that cues from the CSF could act on neurons in the brain and the spinal cord via bordering receptor cells. Candidate neurons to enable such modulation are the cerebrospinal fluid-contacting neurons (CSF-cNs) that are located precisely at the interface between the CSF and neuronal circuits...
September 2017: Journal of Neurogenetics
https://www.readbyqxmd.com/read/28709848/hydrogen-sulfide-alleviates-placental-injury-induced-by-maternal-cigarette-smoke-exposure-during-pregnancy-in-rats
#18
Fusheng Zhao, Fang Lei, Senfeng Zhang, Xiang Yan, Wen Wang, Yu Zheng
Maternal cigarette smoke exposure (CSE) during pregnancy is a well recognized causative factor for placental injury. Hydrogen sulfide (H2S), a gaseous signal molecule, has been shown to exert a protective effect against tissue injury in many organs. This study aimed to investigate whether H2S could alleviate CSE-induced placental injury in rats. Pregnant SD rats were randomly divided into 4 groups: NaCl, CSE, CSE + NaHS (a donor of H2S) and NaHS. On gestational day 21, placental weight was measured. Placental H2S content was assessed by methylene blue method...
July 11, 2017: Nitric Oxide: Biology and Chemistry
https://www.readbyqxmd.com/read/28691238/structure-and-ultrastructure-of-eyes-and-brains-of-thalia-democratica-thaliacea-tunicata-chordata
#19
Katrin Braun, Thomas Stach
Salps are marine planktonic chordates that possess an obligatory alternation of reproductive modes in subsequent generations. Within tunicates, salps represent a derived life cycle and are of interest in considerations of the evolutionary origin of complex anatomical structures and life history strategies. In the present study, the eyes and brains of both the sexual, aggregate blastozooid and the asexual, solitary oozooid stage of Thalia democratica (Forskål, ) were digitally reconstructed in detail based on serial sectioning for light and transmission electron microscopy...
July 10, 2017: Journal of Morphology
https://www.readbyqxmd.com/read/28668562/origin-and-characterization-of-small-membranous-vesicles-present-in-the-venom-of-crotalus-durissus-terrificus
#20
Andréia Souza-Imberg, Sylvia Mendes Carneiro, Karina Cristina Giannotti, Sávio Stefanini Sant'Anna, Norma Yamanouye
Small membranous vesicles are small closed fragments of membrane. They are released from multivesicular bodies (exosomes) or shed from the surface membrane (microvesicles). They contains various bioactive molecules and their molecular composition varies depending on their cellular origin. Small membranous vesicles have been identified in snake venoms, but the origin of these small membranous vesicles in the venom is controversial. The aim of this study was to verify the origin of the small membranous vesicles in venom of Crotalus durissus terrificus by morphological analyses using electron microscopy...
June 28, 2017: Toxicon: Official Journal of the International Society on Toxinology
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