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Apical microvilli

Dhivya Kumar, Rebecca T Thomason, Maya Yankova, Jonathan D Gitlin, Richard E Mains, Betty A Eipper, Stephen M King
The assembly of membranous extensions such as microvilli and cilia in polarized cells is a tightly regulated, yet poorly understood, process. Peptidylglycine α-amidating monooxygenase (PAM), a membrane enzyme essential for the synthesis of amidated bioactive peptides, was recently identified in motile and non-motile (primary) cilia and has an essential role in ciliogenesis in Chlamydomonas, Schmidtea and mouse. In mammalian cells, changes in PAM levels alter secretion and organization of the actin cytoskeleton...
March 14, 2018: Scientific Reports
Muhammad Fiaz, Luis Carlos Martínez, Marilza da Silva Costa, Jamile Fernanda Silva Cossolin, Angelica Plata-Rueda, Wagner Gonzaga Gonçalves, Antônio Euzébio Goulart Sant'Ana, José Cola Zanuncio, José Eduardo Serrão
Annonaceous acetogenins (Annona squamosa Linnaeus) comprises of a series of natural products which are extracted from Annonaceae species, squamocin proved to be highly efficient among those agents. Squamocin is mostly referred as a lethal agent for midgut cells of different insects, with toxic effects when tested against larva of some insects. In present study, LC50 and LC90 of squamocin for A. gemmatalis Hübner (Lepidoptera: Noctuidae) were calculated using probit analysis. Morphological changes in midgut cells were analyzed under light, fluorescence and transmission electron microscopes when larvae were treated with LC50 and LC90 of squamocin for 24, 48 and 72 h...
March 7, 2018: Ecotoxicology and Environmental Safety
Maria Merkulova, Teodor G Păunescu, Anil V Nair, Chia-Yu Wang, Diane E Capen, Peter L Oliver, Sylvie Breton, Dennis Brown
We recently reported that nuclear receptor coactivator 7 (Ncoa7) is a vacuolar proton pumping ATPase (V-ATPase) interacting protein whose function has not been defined. Ncoa7 is highly expressed in the kidney and partially co-localizes with the V-ATPase in collecting duct intercalated cells (ICs). Here, we hypothesized that targeted deletion of the Ncoa7 gene could affect V-ATPase activity in ICs in vivo. We tested this by analyzing the acid-base status, major electrolytes, and kidney morphology of Ncoa7 knockout (KO) mice...
January 31, 2018: American Journal of Physiology. Renal Physiology
Tomasz Walski, Kristof De Schutter, Kaat Cappelle, Els J M Van Damme, Guy Smagghe
Glycans are involved in many biological phenomena, including signal transduction, cell adhesion, immune response or differentiation. Although a few papers have reported on the role of glycans in the development and proper functioning of the insect midgut, no data are available regarding the localization of the glycan structures on the surface of the cells in the gut of insects. In this paper, we analyzed the spatial distribution of glycans present on the surface of the midgut cells in larvae of the cotton leafworm Spodoptera littoralis, an important agricultural pest insect worldwide...
2017: Frontiers in Physiology
Yoshio Yamamoto, Yuko Ozawa, Takuya Yokoyama, Nobuaki Nakamuta
The immunohistochemical characteristics of brush cells in the laryngeal mucosa were examined using immunohistochemistry for various immunohistochemical cell markers including villin at the light and electron microscopic levels. Cells that were immunoreactive to villin were barrel-shaped with thick cytoplasmic processes extending toward the lumen of the laryngeal cavity. Immunoelectron microscopic observations revealed thick and short microvilli with long rootlets of microfilaments. Numerous small clear vesicles and small finger-like cytoplasmic processes were observed in the apical process and lateral membrane, respectively...
February 2018: Journal of Molecular Histology
Jeremy D Cook, Sze Yin Ng, Marcia Lloyd, Shannan Eddington, Hui Sun, Jeremy Nathans, Dean Bok, Roxana A Radu, Gabriel H Travis
Peropsin is a non-visual 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 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)...
December 29, 2017: Journal of Biological Chemistry
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
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
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
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...
December 9, 2017: Biochemical and Biophysical Research Communications
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 Ca2+ 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...
December 4, 2017: Journal of Cell Biology
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
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
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...
December 2017: Stem Cells
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
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
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
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
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
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
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