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Sample records for aedes malpighian tubules

  1. Localization and role of inward rectifier K(+) channels in Malpighian tubules of the yellow fever mosquito Aedes aegypti.

    PubMed

    Piermarini, Peter M; Dunemann, Sonja M; Rouhier, Matthew F; Calkins, Travis L; Raphemot, Rene; Denton, Jerod S; Hine, Rebecca M; Beyenbach, Klaus W

    2015-12-01

    Malpighian tubules of adult female yellow fever mosquitoes Aedes aegypti express three inward rectifier K(+) (Kir) channel subunits: AeKir1, AeKir2B and AeKir3. Here we 1) elucidate the cellular and membrane localization of these three channels in the Malpighian tubules, and 2) characterize the effects of small molecule inhibitors of AeKir1 and AeKir2B channels (VU compounds) on the transepithelial secretion of fluid and electrolytes and the electrophysiology of isolated Malpighian tubules. Using subunit-specific antibodies, we found that AeKir1 and AeKir2B localize exclusively to the basolateral membranes of stellate cells and principal cells, respectively; AeKir3 localizes within intracellular compartments of both principal and stellate cells. In isolated tubules bathed in a Ringer solution containing 34 mM K(+), the peritubular application of VU590 (10 μM), a selective inhibitor of AeKir1, inhibited transepithelial fluid secretion 120 min later. The inhibition brings rates of transepithelial KCl and fluid secretion to 54% of the control without a change in transepithelial NaCl secretion. VU590 had no effect on the basolateral membrane voltage (Vbl) of principal cells, but it significantly reduced the cell input conductance (gin) to values 63% of the control within ∼90 min. In contrast, the peritubular application of VU625 (10 μM), an inhibitor of both AeKir1 and AeKir2B, started to inhibit transepithelial fluid secretion as early as 60 min later. At 120 min after treatment, VU625 was more efficacious than VU590, inhibiting transepithelial KCl and fluid secretion to ∼35% of the control without a change in transepithelial NaCl secretion. Moreover, VU625 caused the Vbl and gin of principal cells to respectively drop to values 62% and 56% of the control values within only ∼30 min. Comparing the effects of VU590 with those of VU625 allowed us to estimate that AeKir1 and AeKir2B respectively contribute to 46% and 20% of the transepithelial K

  2. Ultrastructural changes in the muscles, midgut, hemopoietic organ, imaginal discs and Malpighian tubules of the mosquito Aedes aegypti larvae infected by the fungus Coelomomyces stegomyiae.

    PubMed

    Shoulkamy, M A; Abdelzaher, H M; Shahin, A A

    2001-01-01

    Fungi belonging to the genus Coelomomyces can infect mosquito larvae and develop within the larval hemocoel. To examine fungal development, Aedes aegypti larvae infected with Coelomomyces stegomyiae Keilin were fixed, embedded and sectioned for both light and electron microscopy. While fungal hyphae of C. stegomyiae did not invade cells other than the cuticular epithelial cells, they did penetrate a number of tissues including muscles, midgut, hemopoietic organ, imaginal discs, and Malpighian tubules. PMID:11265168

  3. Transcriptomic Evidence for a Dramatic Functional Transition of the Malpighian Tubules after a Blood Meal in the Asian Tiger Mosquito Aedes albopictus

    PubMed Central

    Esquivel, Carlos J.; Cassone, Bryan J.; Piermarini, Peter M.

    2014-01-01

    Background The consumption of a vertebrate blood meal by adult female mosquitoes is necessary for their reproduction, but it also presents significant physiological challenges to mosquito osmoregulation and metabolism. The renal (Malpighian) tubules of mosquitoes play critical roles in the initial processing of the blood meal by excreting excess water and salts that are ingested. However, it is unclear how the tubules contribute to the metabolism and excretion of wastes (e.g., heme, ammonia) produced during the digestion of blood. Methodology/Principal Findings Here we used RNA-Seq to examine global changes in transcript expression in the Malpighian tubules of the highly-invasive Asian tiger mosquito Aedes albopictus during the first 24 h after consuming a blood meal. We found progressive, global changes in the transcriptome of the Malpighian tubules isolated from mosquitoes at 3 h, 12 h, and 24 h after a blood meal. Notably, a DAVID functional cluster analysis of the differentially-expressed transcripts revealed 1) a down-regulation of transcripts associated with oxidative metabolism, active transport, and mRNA translation, and 2) an up-regulation of transcripts associated with antioxidants and detoxification, proteolytic activity, amino-acid metabolism, and cytoskeletal dynamics. Conclusions/Significance The results suggest that blood feeding elicits a functional transition of the epithelium from one specializing in active transepithelial fluid secretion (e.g., diuresis) to one specializing in detoxification and metabolic waste excretion. Our findings provide the first insights into the putative roles of mosquito Malpighian tubules in the chronic processing of blood meals. PMID:24901705

  4. A de novo transcriptome of the Malpighian tubules in non-blood-fed and blood-fed Asian tiger mosquitoes Aedes albopictus: insights into diuresis, detoxification, and blood meal processing

    PubMed Central

    Esquivel, Carlos J.; Cassone, Bryan J.

    2016-01-01

    Background. In adult female mosquitoes, the renal (Malpighian) tubules play an important role in the post-prandial diuresis, which removes excess ions and water from the hemolymph of mosquitoes following a blood meal. After the post-prandial diuresis, the roles that Malpighian tubules play in the processing of blood meals are not well described. Methods. We used a combination of next-generation sequencing (paired-end RNA sequencing) and physiological/biochemical assays in adult female Asian tiger mosquitoes (Aedes albopictus) to generate molecular and functional insights into the Malpighian tubules and how they may contribute to blood meal processing (3–24 h after blood ingestion). Results/Discussion. Using RNA sequencing, we sequenced and assembled the first de novo transcriptome of Malpighian tubules from non-blood-fed (NBF) and blood-fed (BF) mosquitoes. We identified a total of 8,232 non-redundant transcripts. The Malpighian tubules of NBF mosquitoes were characterized by the expression of transcripts associated with active transepithelial fluid secretion/diuresis (e.g., ion transporters, water channels, V-type H+-ATPase subunits), xenobiotic detoxification (e.g., cytochrome P450 monoxygenases, glutathione S-transferases, ATP-binding cassette transporters), and purine metabolism (e.g., xanthine dehydrogenase). We also detected the expression of transcripts encoding sodium calcium exchangers, G protein coupled-receptors, and septate junctional proteins not previously described in mosquito Malpighian tubules. Within 24 h after a blood meal, transcripts associated with active transepithelial fluid secretion/diuresis exhibited a general downregulation, whereas those associated with xenobiotic detoxification and purine catabolism exhibited a general upregulation, suggesting a reinvestment of the Malpighian tubules’ molecular resources from diuresis to detoxification. Physiological and biochemical assays were conducted in mosquitoes and isolated Malpighian

  5. Calcium Oxalate Accumulation in Malpighian Tubules of Silkworm (Bombyx mori)

    NASA Astrophysics Data System (ADS)

    Wyman, Aaron J.; Webb, Mary Alice

    2007-04-01

    Silkworm provides an ideal model system for study of calcium oxalate crystallization in kidney-like organs, called Malpighian tubules. During their growth and development, silkworm larvae accumulate massive amounts of calcium oxalate crystals in their Malpighian tubules with no apparent harm to the organism. This manuscript reports studies of crystal structure in the tubules along with analyses identifying molecular constituents of tubule exudate.

  6. The single kinin receptor signals to separate and independent physiological pathways in Malpighian tubules of the yellow fever mosquito

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the past we have used the leucokinins, the kinins of the cockroach Leucophaea, to evaluate the mechanism of diuretic action of kinin peptides in Malpighian tubules of the yellow fever mosquito Aedes aegypti. Now using aedeskinins, the kinins of Aedes, are available, we find that in isolated Aede...

  7. Insights into the Malpighian tubule from functional genomics.

    PubMed

    Dow, Julian A T

    2009-02-01

    Classical physiological study of the Malpighian tubule has led to a detailed understanding of fluid transport and its control across several species. With the sequencing of the Drosophila genome, and the concurrent development of post-genomic technologies such as microarrays, proteomics, metabolomics and systems biology, completely unexpected roles for the insect Malpighian tubule have emerged. As the insect body plan is simpler than that of mammals, tasks analogous to those performed by multiple mammalian organ systems must be shared out among insect tissues. As well as the classical roles in osmoregulation, the Malpighian tubule is highly specialized for organic solute transport, and for metabolism and detoxification. In Drosophila, the adult Malpighian tubule is the key tissue for defence against insecticides such as DDT; and it can also detect and mount an autonomous defence against bacterial invasion. While it is vital to continue to set insights obtained in Drosophila into the context of work in other species, the combination of post-genomic technologies and physiological validation can provide insights that might not otherwise have been apparent for many years. PMID:19151219

  8. The single kinin receptor signals to separate and independent physiological pathways in Malpighian tubules of the yellow fever mosquito

    PubMed Central

    Schepel, Stephen A.; Fox, Andrew J.; Miyauchi, Jeremy T.; Sou, Tiffany; Yang, Jason D.; Lau, Kenneth; Blum, Austin W.; Nicholson, Linda K.; Tiburcy, Felix; Nachman, Ronald J.; Piermarini, Peter M.

    2010-01-01

    In the past, we have used the kinins of the cockroach Leucophaea (the leucokinins) to evaluate the mechanism of diuretic action of kinin peptides in Malpighian tubules of the yellow fever mosquito Aedes aegypti. Now using the kinins of Aedes (the aedeskinins), we have found that in isolated Aedes Malpighian tubules all three aedeskinins (1 μM) significantly 1) increased the rate of fluid secretion (V̇S), 2) hyperpolarized the basolateral membrane voltage (Vbl), and 3) decreased the input resistance (Rin) of principal cells, consistent with the known increase in the Cl− conductance of the paracellular pathway in Aedes Malpighian tubules. Aedeskinin-III, studied in further detail, significantly increased V̇S with an EC50 of 1.5 × 10−8 M. In parallel, the Na+ concentration in secreted fluid significantly decreased, and the K+ concentration significantly increased. The concentration of Cl− remained unchanged. While the three aedeskinins triggered effects on Vbl, Rin, and V̇S, synthetic kinin analogs, which contain modifications of the COOH-terminal amide pentapeptide core sequence critical for biological activity, displayed variable effects. For example, kinin analog 1578 significantly stimulated V̇S but had no effect on Vbl and Rin, whereas kinin analog 1708 had no effect on V̇S but significantly affected Vbl and Rin. These observations suggest separate signaling pathways activated by kinins. One triggers the electrophysiological response, and the other triggers fluid secretion. It remains to be determined whether the two signaling pathways emanate from a single kinin receptor via agonist-directed signaling or from a differentially glycosylated receptor. Occasionally, Malpighian tubules did not exhibit a detectable response to natural and synthetic kinins. Hypothetically, the expression of the kinin receptor may depend on developmental, nutritional, and/or reproductive signals. PMID:20538895

  9. The molecular correlates of organ loss: the case of insect Malpighian tubules

    PubMed Central

    Jing, Xiangfeng; White, Thomas A.; Yang, Xiaowei; Douglas, Angela E.

    2015-01-01

    Malpighian tubules play an essential role in excretion, osmoregulation and immunity of most insects. Exceptionally, aphids lack Malpighian tubules, providing the opportunity to investigate the fate of genes expressed in an organ that has undergone evolutionary reduction and loss. Making use of the sequenced genomes of Drosophila melanogaster and the pea aphid Acyrthosiphon pisum, we demonstrated that more than 50% of Drosophila genes expressed specifically in the Malpighian tubules had orthologues in the pea aphid genome and that most of the pea aphid orthologues with detectable expression were identified in the gut transcriptome. Relative to the whole genome, genes functioning in amino acid metabolism are significantly over-represented among the pea aphid orthologues of Malpighian tubule genes, likely reflecting the central importance of amino acid acquisition and metabolism in aphids. This study demonstrates that the evolutionary loss of a key insect organ, the Malpighian tubules, has not been associated with the coupled loss of molecular functions. PMID:25972400

  10. Voltage clamping single cells in intact malpighian tubules of mosquitoes.

    PubMed

    Masia, R; Aneshansley, D; Nagel, W; Nachman, R J; Beyenbach, K W

    2000-10-01

    Principal cells of the Malpighian tubule of the yellow fever mosquito were studied with the methods of two-electrode voltage clamp (TEVC). Intracellular voltage (V(pc)) was -86.7 mV, and input resistance (R(pc)) was 388.5 kOmega (n = 49 cells). In six cells, Ba(2+) (15 mM) had negligible effects on V(pc), but it increased R(pc) from 325.3 to 684.5 kOmega (P < 0.001). In the presence of Ba(2+), leucokinin-VIII (1 microM) increased V(pc) to -101.8 mV (P < 0.001) and reduced R(pc) to 340.2 kOmega (P < 0.002). Circuit analysis yields the following: basolateral membrane resistance, 652. 0 kOmega; apical membrane resistance, 340.2 kOmega; shunt resistance (R(sh)), 344.3 kOmega; transcellular resistance, 992.2 kOmega. The fractional resistance of the apical membrane (0.35) and the ratio of transcellular resistance and R(sh) (3.53) agree closely with values obtained by cable analysis in isolated perfused tubules and confirm the usefulness of TEVC methods in single principal cells of the intact Malpighian tubule. Dinitrophenol (0.1 mM) reversibly depolarized V(pc) from -94.3 to -10.7 mV (P < 0.001) and reversibly increased R(pc) from 412 to 2,879 kOmega (P < 0.001), effects that were duplicated by cyanide (0.3 mM). Significant effects of metabolic inhibition on voltage and resistance suggest a role of ATP in electrogenesis and the maintenance of conductive transport pathways. PMID:10997925

  11. Malpighian tubule development in the red flour beetle (Tribolium castaneum).

    PubMed

    King, Benedict; Denholm, Barry

    2014-11-01

    Malpighian tubules (MpTs) are the major organ for excretion and osmoregulation in most insects. MpT development is characterised for Drosophila melanogaster, but not other species. We therefore do not know the extent to which the MpT developmental programme is conserved across insects. To redress this we provide a comprehensive description of MpT development in the beetle Tribolium castaneum (Coleoptera), a species separated from Drosophila by >315 million years. We identify similarities with Drosophila MpT development including: 1) the onset of morphological development, beginning when tubules bud from the gut and proliferate to increase organ size. 2) the tubule is shaped by convergent-extension movements and oriented cell divisions. 3) differentiated tip cells activate EGF-signalling in distal MpT cells through the ligand Spitz. 4) MpTs contain two main cell types - principal and stellate cells, differing in morphology and gene expression. We also describe development of the beetle cryptonephridial system, an adaptation for water conservation, which represents a major modification of the MpT ground plan characterised by intimate association between MpTs and rectum. This work establishes a new model to compare MpT development across insects, and provides a framework to help understand how an evolutionary novelty - the cryptonephridial system - arose during organ evolution. PMID:25242057

  12. [Micromorphology of the malpighian tubules in the louse Pediculus humanus corporis (Anoplura)].

    PubMed

    Chaĭka, S Iu

    1985-01-01

    The ultrastructure of the Malpighian tubes in human louse Pediculus humanus corporis has been studied. The cells of the Malpighian tubules have the uniform structure: the apical surface is covered with microvilli, the basal plasmatic membrana forms relatively small invaginations. The microvilli are most developed in cells of the proximal department of the Malpighian tubules. Microvilli of the apical surface of the cells do not contain mitochondria which are localized mainly in supranuclear part of the cell. Cells are lined with a homogenous basal membrane. PMID:3986247

  13. The influence of neuropeptides on Malpighian tubule writhing and its significance for excretion.

    PubMed

    Coast, G M

    1998-01-01

    Diuretic peptides (locustakinin and Locusta-DH) increase the spontaneous contractile activity of visceral muscle fibers associated with Malpighian tubules from the migratory locust (Locusta migratoria) at concentrations that increase urine production. Muscle activity is shown to assist the flow of material in the tubule lumen, but is not essential for diuresis. Tubule writhing also serves to reduce unstirred layers (USLs) at the basolateral surface of the epithelium and thereby facilitates the excretion of solutes entering the lumen by passive diffusion. PMID:9533634

  14. Effects of Bacillus thuringiensis kurstaki on Malpighian tubule cells of Thaumetopoea pityocampa (Lepidoptera: Thaumetopoeidae) larvae.

    PubMed

    Ogutchu, Ayşe; Suludere, Zekiye; Uzunhisarcikli, Meltem; Kalender, Yusuf

    2005-01-01

    In this study effects of Bacillus thuringiensis kurstaki (Btk) on Malpighian tubule cells of Thaumetopoea pityocampa (Lepidoptera: Thaumetopoeidae) larvae was investigated by electron microscopy. 3 mg/l Btk was given with food. After Btk administration, the Malpighian tubule cells were investigated and compared with a control group. 3 and 6 hrs after Btk administration swelling in Malpighian tubule cells was observed. Swelling of mitochondria and separation of their cristae was seen after 12 hrs. After 24 hrs dissolution of the basal cytoplasm, swelling and vacuolization of all mitochondria, partial dissolution of the nucleoplasm, and swelling and separation ofmicrovilli was documented. A membrane-body in the nucleus was seen after 48 hrs. The nucleoplasm was completely dissolved after 72 hrs and after 96 hrs large vacuoles appeared in the cytoplasm and shortening of microvilli was observed. PMID:16212102

  15. Proteomic changes in response to crystal formation in Drosophila Malpighian tubules.

    PubMed

    Chung, Vera Y; Konietzny, Rebecca; Charles, Philip; Kessler, Benedikt; Fischer, Roman; Turney, Benjamin W

    2016-04-01

    Kidney stone disease is a major health burden with a complex and poorly understood pathophysiology. Drosophila Malpighian tubules have been shown to resemble human renal tubules in their physiological function. Herein, we have used Drosophila as a model to study the proteomic response to crystal formation induced by dietary manipulation in Malpighian tubules. Wild-type male flies were reared in parallel groups on standard medium supplemented with lithogenic agents: control, Sodium Oxalate (NaOx) and Ethylene Glycol (EG). Malpighian tubules were dissected after 2 weeks to visualize crystals with polarized light microscopy. The parallel group was dissected for protein extraction. A new method of Gel Assisted Sample Preparation (GASP) was used for protein extraction. Differentially abundant proteins (p<0.05) were identified by label-free quantitative proteomic analysis in flies fed with NaOx and EG diet compared with control. Their molecular functions were further screened for transmembrane ion transporter, calcium or zinc ion binder. Among these, 11 candidate proteins were shortlisted in NaOx diet and 16 proteins in EG diet. We concluded that GASP is a proteomic sample preparation method that can be applied to individual Drosophila Malpighian tubules. Our results may further increase the understanding of the pathophysiology of human kidney stone disease. PMID:27064297

  16. Multicopper oxidase-1 is required for iron homeostasis in Malpighian tubules of Helicoverpa armigera

    PubMed Central

    Liu, Xiaoming; Sun, Chengxian; Liu, Xiaoguang; Yin, Xinming; Wang, Baohai; Du, Mengfang; An, Shiheng

    2015-01-01

    Multicopper oxidases (MCOs) are enzymes that contain 10 conserved histidine residues and 1 cysteine residue. MCO1 has been extensively investigated in the midgut because this MCO is implicated in ascorbate oxidation, iron homeostasis and immune responses. However, information regarding the action of MCO1 in Malpighian tubules is limited. In this study, Helicoverpa armigera was used as a model to investigate the function of MCO1 in Malpighian tubules. Sequence analysis results revealed that HaMCO1 exhibits typical MCO characteristics, with 10 histidine and 1 cysteine residues for copper ion binding. HaMCO1 was also found to be highly abundant in Malpighian tubules. Temporal expression patterns indicated that HaMCO1 is mainly expressed during larval molting stages. Hormone treatments [the molting hormone 20-hydroxyecdysone (20E) and juvenile hormone (JH)] revealed that 20E inhibits HaMCO1 transcript expression via its heterodimer receptor, which consists of ecdysone receptor (EcR) and ultraspiracle (USP), and that JH counteracts the action of 20E to activate HaMCO1 transcript expression via its intracellular receptor methoprene-tolerant (Met). HaMCO1 knockdown caused a significant decrease in iron accumulation and also significantly reduced transferrin and ferritin transcript expression. Therefore, HaMCO1 is coordinately regulated by 20E and JH and is required for iron homeostasis in Malpighian tubules. PMID:26437857

  17. Multicopper oxidase-1 is required for iron homeostasis in Malpighian tubules of Helicoverpa armigera.

    PubMed

    Liu, Xiaoming; Sun, Chengxian; Liu, Xiaoguang; Yin, Xinming; Wang, Baohai; Du, Mengfang; An, Shiheng

    2015-01-01

    Multicopper oxidases (MCOs) are enzymes that contain 10 conserved histidine residues and 1 cysteine residue. MCO1 has been extensively investigated in the midgut because this MCO is implicated in ascorbate oxidation, iron homeostasis and immune responses. However, information regarding the action of MCO1 in Malpighian tubules is limited. In this study, Helicoverpa armigera was used as a model to investigate the function of MCO1 in Malpighian tubules. Sequence analysis results revealed that HaMCO1 exhibits typical MCO characteristics, with 10 histidine and 1 cysteine residues for copper ion binding. HaMCO1 was also found to be highly abundant in Malpighian tubules. Temporal expression patterns indicated that HaMCO1 is mainly expressed during larval molting stages. Hormone treatments [the molting hormone 20-hydroxyecdysone (20E) and juvenile hormone (JH)] revealed that 20E inhibits HaMCO1 transcript expression via its heterodimer receptor, which consists of ecdysone receptor (EcR) and ultraspiracle (USP), and that JH counteracts the action of 20E to activate HaMCO1 transcript expression via its intracellular receptor methoprene-tolerant (Met). HaMCO1 knockdown caused a significant decrease in iron accumulation and also significantly reduced transferrin and ferritin transcript expression. Therefore, HaMCO1 is coordinately regulated by 20E and JH and is required for iron homeostasis in Malpighian tubules. PMID:26437857

  18. First transcriptional survey of the Malpighian tubules of giant mealworm, Zophobas morio (Coleoptera: Tenebrionidae).

    PubMed

    Silva, J R; Prado, R A; Amaral, D T; Viviani, V R

    2015-01-01

    The Malpighian tubules play a key role in insect osmoregulation. Although a transcriptional analysis has been done for the Malpighian tubules in Drosophila melanogaster (Diptera), no functional genomics analysis has yet been carried out for any Coleoptera species. Recently, we constructed a cDNA library from Malpighian tubules of larval Zophobas morio, a close relative of Tribolium castaneum, and cloned the cDNA for an AMP/CoA-ligase with luciferase-like enzyme properties. Using this cDNA library, we randomly isolated, partially sequenced and analyzed ca. 540 clones, obtaining the first transcriptional profile of the most representative expressed genes, and associated them with their possible biological functions. A high percentage of mitochondrial genes was found, which is consistent with the high metabolic activity required by this organ during the formation of primary urine. Common transcripts included those for enzymes involved in osmoregulation, such as solute transporters and ATPases, and in detoxification and excretion, such as cytochrome P450, glutathione S-transferase, alcohol dehydrogenase. The presence of AMP/CoA-ligases, which activate exogenous carboxylic acids such as firefly D-luciferin suggests their participation in important new xenobiotic excretion/detoxification roles in Malpighian tubule physiology. PMID:25729980

  19. Effects of sublethal doses of imidacloprid in Malpighian tubules of Africanized Apis mellifera (Hymenoptera, Apidae).

    PubMed

    Rossi, Caroline de Almeida; Roat, Thaisa Cristina; Tavares, Daiana Antonia; Cintra-Socolowski, Priscila; Malaspina, Osmar

    2013-05-01

    In Brazil, imidacloprid is a widely used insecticide on agriculture and can harm bees, which are important pollinators. The active ingredient imidacloprid has action on the nervous system of the insects. However, little has been studied about the actions of the insecticide on nontarget organs of insects, such as the Malpighian tubules that make up the excretory and osmoregulatory system. Hence, in this study, we evaluated the effects of chronic exposure to sublethal doses of imidacloprid in Malpighian tubules of Africanized Apis mellifera. In the tubules of treated bees, we found an increase in the number of cells with picnotic nuclei, the lost of part of the cell into the lumen, and a homogenization of coloring cytoplasm. Furthermore, we observed the presence of cytoplasmic vacuolization. We confirmed the increased occurrence of picnotic nuclei by using the Feulgan reaction, which showed the chromatin compaction was more intense in the tubules of bees exposed to the insecticide. We observed an intensification of the staining of the nucleus with Xylidine Ponceau, further verifying the cytoplasmic negative regions that may indicate autophagic activity. Additionally, immunocytochemistry experiments showed TUNEL positive nuclei in exposed bees, implicating increased cell apoptosis after chronic imidacloprid exposure. In conclusion, our results indicate that very low concentrations of imidacloprid lead to cytotoxic activity in the Malpighian tubules of exposed bees at all tested times for exposure and imply that this insecticide can alter honey bee physiology. PMID:23483717

  20. A SLC4-like anion exchanger from renal tubules of the mosquito (Aedes aegypti): evidence for a novel role of stellate cells in diuretic fluid secretion.

    PubMed

    Piermarini, Peter M; Grogan, Laura F; Lau, Kenneth; Wang, Li; Beyenbach, Klaus W

    2010-03-01

    Transepithelial fluid secretion across the renal (Malpighian) tubule epithelium of the mosquito (Aedes aegypti) is energized by the vacuolar-type (V-type) H(+)-ATPase and not the Na(+)-K(+)-ATPase. Located at the apical membrane of principal cells, the V-type H(+)-ATPase translocates protons from the cytoplasm to the tubule lumen. Secreted protons are likely to derive from metabolic H(2)CO(3), which raises questions about the handling of HCO(3)(-) by principal cells. Accordingly, we tested the hypothesis that a Cl/HCO(3) anion exchanger (AE) related to the solute-linked carrier 4 (SLC4) superfamily mediates the extrusion of HCO(3)(-) across the basal membrane of principal cells. We began by cloning from Aedes Malpighian tubules a full-length cDNA encoding an SLC4-like AE, termed AeAE. When expressed heterologously in Xenopus oocytes, AeAE is both N- and O-glycosylated and mediates Na(+)-independent intracellular pH changes that are sensitive to extracellular Cl(-) concentration and to DIDS. In Aedes Malpighian tubules, AeAE is expressed as two distinct forms: one is O-glycosylated, and the other is N-glycosylated. Significantly, AeAE immunoreactivity localizes to the basal regions of stellate cells but not principal cells. Concentrations of DIDS that inhibit AeAE activity in Xenopus oocytes have no effects on the unstimulated rates of fluid secretion mediated by Malpighian tubules as measured by the Ramsay assay. However, in Malpighian tubules stimulated with kinin or calcitonin-like diuretic peptides, DIDS reduces the diuretic rates of fluid secretion to basal levels. In conclusion, Aedes Malpighian tubules express AeAE in the basal region of stellate cells, where this transporter may participate in producing diuretic rates of transepithelial fluid secretion. PMID:20042685

  1. Cytotoxic effects of thiamethoxam in the midgut and malpighian tubules of Africanized Apis mellifera (Hymenoptera: Apidae).

    PubMed

    Catae, Aline Fernanda; Roat, Thaisa Cristina; De Oliveira, Regiane Alves; Nocelli, Roberta Cornélio Ferreira; Malaspina, Osmar

    2014-04-01

    Due to its expansion, agriculture has become increasingly dependent on the use of pesticides. However, the indiscriminate use of insecticides has had additional effects on the environment. These products have a broad spectrum of action, and therefore the insecticide affects not only the pests but also non-target insects such as bees, which are important pollinators of agricultural crops and natural environments. Among the most used pesticides, the neonicotinoids are particularly harmful. One of the neonicotinoids of specific concern is thiamethoxam, which is used on a wide variety of crops and is toxic to bees. Thus, this study aimed to analyze the effects of this insecticide in the midgut and Malpighian tubule cells of Africanized Apis mellifera. Newly emerged workers were exposed until 8 days to a diet containing a sublethal dose of thiamethoxam equal to 1/10 of LC₅₀ (0.0428 ng a.i./l L of diet). The bees were dissected and the organs were processed for transmission electron microscopy. The results showed that thiamethoxam is cytotoxic to midgut and Malpighian tubules. In the midgut, the damage was more evident in bees exposed to the insecticide on the first day. On the eighth day, the cells were ultrastructurally intact suggesting a recovery of this organ. The Malpighian tubules showed pronounced alterations on the eighth day of exposure of bees to the insecticide. This study demonstrates that the continuous exposure to a sublethal dose of thiamethoxam can impair organs that are used during the metabolism of the insecticide. PMID:24470251

  2. A dynamic paracellular pathway serves diuresis in mosquito Malpighian (renal) tubules

    PubMed Central

    Beyenbach, Klaus W.

    2012-01-01

    Female mosquitoes gorge on vertebrate blood, a rich nutrient source for developing eggs. But gorging meals increase the risk of predation. Mosquitoes are quick to reduce the flight payload with a potent diuresis. Diuretic peptides of the insect kinin family induce a tenfold-reduction in the paracellular resistance of Malpighian tubules and increase the paracellular permeation of Cl−, the counterion of the transepithelial secretion of Na+ and K+. As a result, the transepithelial secretion of NaCl and KCl and water increases. Insect kinins signal to the opening of the paracellular pathway via G protein-coupled receptors and the elevation of intracellular [Ca2+], which leads to the reorganization of the cytoskeleton associated with the septate junction. The reorganization may affect the septate junctional proteins that control the barrier and permselectivity properties of the paracellular pathway. The proteins involved in the embryonic formation of the septate junction and in epithelial polarization are largely known for ectodermal epithelia, but the proteins that form and mediate the dynamic functions of the septate junction in Malpighian tubules remain to be determined. PMID:22731730

  3. The control of Malpighian tubule secretion in a predacious hemipteran insect, the spined soldier bug Podisus maculiventris (Heteroptera, Pentatomidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spined soldier bugs, Podisus maculiventris, are heteropteran insects that feed voraciously on other insects, particular the soft bodied larval forms of Lepidoptera and Coleoptera. The response of P. maculiventris Malpighian tubules (MT) to serotonin and known diuretic and antidiuretic peptides has b...

  4. Secretion of Na(+), K(+) and fluid by the Malpighian (renal) tubule of the larval cabbage looper Trichoplusia ni (Lepidoptera: Noctuidae).

    PubMed

    Ruiz-Sanchez, Esau; O'Donnell, Michael J; Donini, Andrew

    2015-11-01

    The Malpighian (renal) tubules play important roles in ionic and osmotic homeostasis in insects. In Lepidoptera, the Malpighian tubules are structurally regionalized and the concentration of Na(+) and K(+) in the secreted fluid varies depending on the segment of tubule analyzed. In this work, we have characterized fluid and ion (Na(+), K(+), H(+)) transport by tubules of the larval stage of the cabbage looper Trichoplusia ni; we have also evaluated the effects of fluid secretion inhibitors and stimulants on fluid and ion transport. Ramsay assays showed that fluid was secreted by the iliac plexus but not by the yellow and white regions of the tubule. K(+) and Na(+) were secreted by the distal iliac plexus (DIP) and K(+) was reabsorbed in downstream regions. The fluid secretion rate decreased>50% after 25μM bafilomycin A1, 500μM amiloride or 50μM bumetanide was added to the bath. The concentration of K(+) in the secreted fluid did not change, whereas the concentration of Na(+) in the secreted fluid decreased significantly when tubules were exposed to bafilomycin A1 or amiloride. Addition of 500μM cAMP or 1μM 5-HT to the bath stimulated fluid secretion and resulted in a decrease in K(+) concentration in the secreted fluid. An increase in Na(+) concentration in the secreted fluid was observed only in cAMP-stimulated tubules. Secreted fluid pH and the transepithelial electrical potential (TEP) did not change when tubules were stimulated. Taken together, our results show that the secretion of fluid is carried out by the upper regions (DIP) in T. ni Malpighian tubules. Upper regions of the tubules secrete K(+), whereas lower regions reabsorb it. Stimulation of fluid secretion is correlated with a decrease in the K(+)/Na(+) ratio. PMID:26432549

  5. Proteomic-Based Insight into Malpighian Tubules of Silkworm Bombyx mori

    PubMed Central

    Liu, Shi-ping; Yi, Qi-ying; Hu, Cui-mei; Wang, Chen; Xia, Qing-you; Zhao, Ping

    2013-01-01

    Malpighian tubules (MTs) are highly specific organs of arthropods (Insecta, Myriapoda and Arachnida) for excretion and osmoregulation. In order to highlight the important genes and pathways involved in multi-functions of MTs, we performed a systematic proteomic analysis of silkworm MTs in the present work. Totally, 1,367 proteins were identified by one-dimensional gel electrophoresis coupled with liquid chromatography-tandem mass spectrometry, and as well as by Trans Proteomic Pipeline (TPP) and Absolute protein expression (APEX) analyses. Forty-one proteins were further identified by two-dimensional gel electrophoresis. Some proteins were revealed to be significantly associated with various metabolic processes, organic solute transport, detoxification and innate immunity. Our results might lay a good foundation for future functional studies of MTs in silkworm and other lepidoptera. PMID:24098719

  6. Segment-specific Ca(2+) transport by isolated Malpighian tubules of Drosophila melanogaster: A comparison of larval and adult stages.

    PubMed

    Browne, Austin; O'Donnell, Michael J

    2016-04-01

    Haemolymph calcium homeostasis in insects is achieved through the regulation of calcium excretion by Malpighian tubules in two ways: (1) sequestration of calcium within biomineralized granules and (2) secretion of calcium in soluble form within the primary urine. Using the scanning ion-selective electrode technique (SIET), basolateral Ca(2+) transport was measured at the distal, transitional, main and proximal tubular segments of anterior tubules isolated from both 3rd instar larvae and adults of the fruit fly Drosophila melanogaster. Basolateral Ca(2+) transport exceeded transepithelial secretion by 800-fold and 11-fold in anterior tubules of larvae and adults, respectively. The magnitude of Ca(2+) fluxes across the distal tubule of larvae and adults were larger than fluxes across the downstream segments by 10 and 40 times, respectively, indicating a dominant role for the distal segment in whole animal Ca(2+) regulation. Basolateral Ca(2+) transport across distal tubules of Drosophila varied throughout the life cycle; Ca(2+) was released by distal tubules of larvae, taken up by distal tubules of young adults and was released once again by tubules of adults ⩾ 168 h post-eclosion. In adults and larvae, SIET measurements revealed sites of both Ca(2+) uptake and Ca(2+) release across the basolateral surface of the distal segment of the same tubule, indicating that Ca(2+) transport is bidirectional. Ca(2+) uptake across the distal segment of tubules of young adults and Ca(2+) release across the distal segment of tubules of older adults was also suggestive of reversible Ca(2+) storage. Our results suggest that the distal tubules of D. melanogaster are dynamic calcium stores which allow efficient haemolymph calcium regulation through active Ca(2+) sequestration during periods of high dietary calcium intake and passive Ca(2+) release during periods of calcium deficiency. PMID:26802560

  7. Role of an apical K,Cl cotransporter in urine formation by renal tubules of the yellow fever mosquito (Aedes aegypti).

    PubMed

    Piermarini, Peter M; Hine, Rebecca M; Schepel, Matthew; Miyauchi, Jeremy; Beyenbach, Klaus W

    2011-11-01

    The K,Cl cotransporters (KCCs) of the SLC12 superfamily play critical roles in the regulation of cell volume, concentrations of intracellular Cl(-), and epithelial transport in vertebrate tissues. To date, the role(s) of KCCs in the renal functions of mosquitoes and other insects is less clear. In the present study, we sought molecular and functional evidence for the presence of a KCC in renal (Malpighian) tubules of the mosquito Aedes aegypti. Using RT-PCR on Aedes Malpighian tubules, we identified five alternatively spliced partial cDNAs that encode putative SLC12-like KCCs. The majority transcript is AeKCC1-A(1); its full-length cDNA was cloned. After expression of the AeKCC1-A protein in Xenopus oocytes, the Cl(-)-dependent uptake of (86)Rb(+) is 1) activated by 1 mM N-ethylmaleimide and cell swelling, 2) blocked by 100 μM dihydroindenyloxyalkanoic acid (DIOA), and 3) dependent upon N-glycosylation of AeKCC1-A. In Aedes Malpighian tubules, AeKCC1 immunoreactivity localizes to the apical brush border of principal cells, which are the predominant cell type in the epithelium. In vitro physiological assays of Malpighian tubules show that peritubular DIOA (10 μM): 1) significantly reduces both the control and diuretic rates of transepithelial fluid secretion and 2) has negligible effects on the membrane voltage and input resistance of principal cells. Taken together, the above observations indicate the presence of a KCC in the apical membrane of principal cells where it participates in a major electroneutral transport pathway for the transepithelial secretion of fluid in this highly electrogenic epithelium. PMID:21813871

  8. A transcriptional and proteomic survey of Arachnocampa luminosa (Diptera: Keroplatidae) lanterns gives insights into the origin of bioluminescence from the Malpighian tubules in Diptera.

    PubMed

    Silva, J R; Amaral, D T; Hastings, J W; Wilson, T; Viviani, V R

    2015-11-01

    Fungus-gnats of the genus Arachnocampa are unique among bioluminescent insects for displaying blue-green bioluminescence, and are responsible for one of the most beautiful bioluminescence spectacles on the roofs of the Waitomo Caves. Despite morphological studies showing that Arachnocampa larval lanterns involve specialization of the Malpighian tubules, the biochemical origin of their bioluminescence remains enigmatic. Using a cDNA library previously constructed from lanterns of the New Zealand glowworm A. luminosa, we carried out the first transcriptional analysis of ~ 500 expressed sequence tags (ESTs) to identify putative candidate proteins for light production, and to better understand the molecular physiology of the lanterns and their relationship with Malpighian tubule physiology. The analysis showed an abundance of hexamerin-like proteins, as well as luciferase-like enzymes, indicating a possible critical role for these proteins in bioluminescence. These findings were corroborated by proteomic analysis of lantern extracts, which showed the presence of hexamerins and luciferase-like enzymes. Other gene products typical of Malpighian tubules, such as detoxifying enzymes, were also found. The results support the existence of an evolutionary link between Malpighian tubule detoxification and the origin of bioluminescence in these Diptera. PMID:25676901

  9. An antidiuretic peptide (Tenmo-ADFb) with kinin-like diuretic activity on Malpighian tubules of the house cricket, Acheta domesticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A. domesticus has anantidiuretic hormone that acts to reduce Malpighian tubule secretion. Identified peptides know to reduce secretion of primary urine (Tenmo-ADFa and ADFb, and Manse-CAP2b) were tested as candidates for this unidentified hormone, along with their second messenger cyclic GMP. Only...

  10. A Novel Member of the Trehalose Transporter Family Functions as an H+-Dependent Trehalose Transporter in the Reabsorption of Trehalose in Malpighian Tubules

    PubMed Central

    Kikuta, Shingo; Hagiwara-Komoda, Yuka; Noda, Hiroaki; Kikawada, Takahiro

    2012-01-01

    In insects, Malpighian tubules are functionally analogous to mammalian kidneys in that they not only are essential to excrete waste molecules into the lumen but also are responsible for the reabsorption of indispensable molecules, such as sugars, from the lumen to the principal cells. Among sugars, the disaccharide trehalose is highly important to insects because it is the main hemolymph sugar to serve as a source of energy and carbon. The trehalose transporter TRET1 participates in the transfer of newly synthesized trehalose from the fat body across the cellular membrane into the hemolymph. Although transport proteins must play a pivotal role in the reabsorption of trehalose in Malpighian tubules, the molecular context underlying this process remains obscure. Previously, we identified a Tret1 homolog (Nlst8) that is expressed principally in the Malpighian tubules of the brown planthopper (BPH). Here, we used the Xenopus oocyte expression system to show that NlST8 exerts trehalose transport activity that is elevated under low pH conditions. These functional assays indicate that Nlst8 encodes a proton-dependent trehalose transporter (H-TRET1). To examine the involvement of Nlst8 in trehalose reabsorption, we analyzed the sugar composition of honeydew by using BPH with RNAi gene silencing. Trehalose was detected in the honeydew as waste excreted from Nlst8-dsRNA-injected BPH under hyperglycemic conditions. However, trehalose was not expelled from GFP-dsRNA-injected BPH even under hyperglycemic conditions. We conclude that NlST8 could participate in trehalose reabsorption driven by a H+ gradient from the lumen to the principal cells of the Malpighian tubules. PMID:22934042

  11. The rectal complex and Malpighian tubules of the cabbage looper (Trichoplusia ni): regional variations in Na+ and K+ transport and cation reabsorption by secondary cells.

    PubMed

    O'Donnell, Michael J; Ruiz-Sanchez, Esau

    2015-10-01

    In larvae of most Lepidoptera the distal ends of the Malpighian tubules are closely applied to the rectal epithelia and are ensheathed within the perinephric membrane, thus forming the rectal complex. The cryptonephric Malpighian tubules within the rectal complex are bathed in fluid within a functional compartment, the perinephric space, which is separate from the haemolymph. In this study, the scanning ion-selective electrode technique (SIET) was used to measure transport of Na(+) and K(+) across the rectal complex and across multiple regions of the Malpighian tubules of larvae of the cabbage looper Trichoplusia ni. Measurements were made in an intact preparation in which connections of the tubules upstream to the rectal complex and downstream to the urinary bladder and gut remained intact. SIET measurements revealed reabsorption of Na(+) and K(+) across the intact rectal complex and into the bath (haemolymph), with K(+) fluxes approximately twice as large as those of Na(+). Analyses of fluxes in larvae with empty guts, found in recently moulted larvae, versus those with full guts highlighted differences in the rates of K(+) or Na(+) transport within tubule regions that appeared morphologically homogeneous, such as the rectal lead. The distal rectal lead of larvae with empty guts reabsorbed K(+), whereas the same region secreted K(+) in tubules of larvae with full guts. SIET measurements of the ileac plexus also indicated a novel role for secondary (type II) cells in cation reabsorption. Secondary cells reabsorb K(+), whereas the adjacent principal (type I) cells secrete K(+). Na(+) is reabsorbed by both principal and secondary cells, but the rate of reabsorption by the secondary cells is approximately twice the rate in the adjacent principal cells. PMID:26491192

  12. Malpighian Tubule Cells in Overwintering Cave Crickets Troglophilus cavicola (Kollar, 1833) and T. neglectus Krauss, 1879 (Rhaphidophoridae, Ensifera)

    PubMed Central

    Lipovšek, Saška; Novak, Tone; Janžekovič, Franc; Weiland, Nina

    2016-01-01

    During winter, cave cricket larvae undergo dormancy in subterranean habitats; this dormancy is termed diapause in second year Troglophilus cavicola larvae because they mature during this time, and termed quiescence in T. neglectus, because they mature after dormancy. Here we used electron microscopy to analyze ultrastructural changes in the epithelial cells in the Malpighian tubules (MTs) of T. cavicola during diapause, in order to compare them with previous findings on T. neglectus. Moreover, the autophagosomes were studied with immunofluorescence microscopy in both species. Although the basic ultrastructure of the cells was similar, specific differences appeared during overwintering. During this natural starvation period, the nucleus, rER, the Golgi apparatus and mitochondria did not show structural changes, and the spherites were exploited. The abundances of autophagic structures in both species increased during overwintering. At the beginning of overwintering, in both species and sexes, the rates of cells with autophagic structures (phagophores, autophagosomes, autolysosomes and residual bodies) were low, while their rates increased gradually towards the end of overwintering. Between sexes, in T. cavicola significant differences were found in the autophagosome abundances in the middle and at the end, and in T. neglectus at the end of overwintering. Females showed higher rates of autophagic cells than males, and these were more abundant in T. cavicola. Thus, autophagic processes in the MT epithelial cells induced by starvation are mostly parallel in diapausing T. cavicola and quiescent T. neglectus, but more intensive in diapausing females. PMID:27379687

  13. Ultrastructural investigation of the spore-forming protist Nephridiophaga blattellae in the Malpighian tubules of the German cockroach Blattella germanica.

    PubMed

    Radek, R; Herth, W

    1999-03-01

    Multinuclear plasmodia of the sporogenic protist Nephridiophaga blattellae are found intracellularly and in the lumen of the Malpighian tubules of the German cockroach Blattella germanica. Spore formation occurs only in the lumen. During sporogony, about 10-35 spores measuring 5.5x3.2 microm are endogenously formed within a plasmodium. Sporoblasts arise by the fusion of cisternae of the endoplasmic reticulum into a double membranous wall, which encloses a generative nucleus plus a portion of cytoplasm. Several somatic nuclei remain in the residual cytoplasm. Sporoblast and residual cytoplasm include mitochondria of the tubular type, endoplasmic reticulum, and many free ribosomes. During spore maturation, electron-dense wall material is deposited between the spore membranes, and the spores gain their typical oval, biconcave form. Freeze-etched spores reveal a small, central, cap-like structure, which may be the site where an infectious sporoplasm could emerge. Mature spores always have one nucleus, whereas early sporoblast stages with two small nuclei were found by transmission electron microscopy. Many nuclei of different developmental stages contain granules within the nuclear envelope. The systematic position of N. blattellae is unresolved. In certain respects it is reminiscent of Haplosporidia. However, the organisms of the two groups have different spore-forming processes and haplosporosomes are missing in the nephridiophagids. Therefore a new phylum might have to be erected for members of the family Nephridiophagidae. PMID:9951966

  14. Malpighian Tubule Cells in Overwintering Cave Crickets Troglophilus cavicola (Kollar, 1833) and T. neglectus Krauss, 1879 (Rhaphidophoridae, Ensifera).

    PubMed

    Lipovšek, Saška; Novak, Tone; Janžekovič, Franc; Weiland, Nina; Leitinger, Gerd

    2016-01-01

    During winter, cave cricket larvae undergo dormancy in subterranean habitats; this dormancy is termed diapause in second year Troglophilus cavicola larvae because they mature during this time, and termed quiescence in T. neglectus, because they mature after dormancy. Here we used electron microscopy to analyze ultrastructural changes in the epithelial cells in the Malpighian tubules (MTs) of T. cavicola during diapause, in order to compare them with previous findings on T. neglectus. Moreover, the autophagosomes were studied with immunofluorescence microscopy in both species. Although the basic ultrastructure of the cells was similar, specific differences appeared during overwintering. During this natural starvation period, the nucleus, rER, the Golgi apparatus and mitochondria did not show structural changes, and the spherites were exploited. The abundances of autophagic structures in both species increased during overwintering. At the beginning of overwintering, in both species and sexes, the rates of cells with autophagic structures (phagophores, autophagosomes, autolysosomes and residual bodies) were low, while their rates increased gradually towards the end of overwintering. Between sexes, in T. cavicola significant differences were found in the autophagosome abundances in the middle and at the end, and in T. neglectus at the end of overwintering. Females showed higher rates of autophagic cells than males, and these were more abundant in T. cavicola. Thus, autophagic processes in the MT epithelial cells induced by starvation are mostly parallel in diapausing T. cavicola and quiescent T. neglectus, but more intensive in diapausing females. PMID:27379687

  15. Tumor suppressors Sav/Scrib and oncogene Ras regulate stem cell transformation in adult Drosophila Malpighian Tubules

    PubMed Central

    Zeng, Xiankun; Singh, Shree Ram; Hou, David; Hou, Steven X.

    2012-01-01

    An increasing body of evidence suggests that tumors might originate from a few transformed cells that share many properties with normal stem cells. However, it remains unclear how normal stem cells are transformed into cancer stem cells. Here, we demonstrated that mutations causing the loss of tumor suppressor Sav or Scrib or activation of the oncogene Ras transform normal stem cells into cancer stem cells through a multistep process in the adult Drosophila Malpighian Tubules (MTs). In wild-type MTs, each stem cell generates one self-renewing and one differentiating daughter cell. However, in flies with loss-of-function sav or scrib or gain-of-function Ras mutations, both daughter cells grew and behaved like stem cells, leading to the formation of tumors in MTs. Ras functioned downstream of Sav and Scrib in regulating the stem cell transformation. The Ras-transformed stem cells exhibited many of the hallmarks of cancer, such as increased proliferation, reduced cell death, and failure to differentiate. We further demonstrated that several signal transduction pathways (including MEK/MAPK, RhoA, PKA, and TOR) mediate Rasṕ function in the stem cell transformation. Therefore, we have identified a molecular mechanism that regulates stem cell transformation, and this finding may lead to strategies for preventing tumor formation in certain organs. PMID:20432470

  16. Neurochemical fine tuning of a peripheral tissue: peptidergic and aminergic regulation of fluid secretion by Malpighian tubules in the tobacco hawkmoth M. sexta.

    PubMed

    Skaer, N J V; Nässel, D R; Maddrell, S H P; Tublitz, N J

    2002-07-01

    The actions of various peptides and other compounds on fluid secretion by Malpighian tubules in the tobacco hawkmoth Manduca sexta sexta are investigated in this study. Using a newly developed pharate adult Malpighian tubule bioassay, we show that three tachykinin-related peptides (TRPs), leucokinin I, serotonin (5-HT), octopamine, the cardioacceleratory peptides 1a, 1b and 2c, cGMP and cAMP each cause an increase in the rate of fluid secretion in pharate adult tubules. Whereas the possible hormonal sources of biogenic amines and some of the peptides are known, the distribution of TRPs has not been investigated previously in M. sexta. Thus we performed immunocytochemistry using an anti-TRP antiserum. We show the presence of TRP-like material in a small subset of cells in the M. sexta central nervous system (CNS). The larval brain contains approximately 60 TRP-immunopositive cells and there are approximately 100 such cells in the adult brain including the optic lobes. Every ganglion of the ventral nerve cord also contains TRP-like immunoreactive cells. No TRP-containing neurosecretory cells were seen in the CNS, but endocrine cells of the midgut reacted with the antiserum. We propose the hypothesis that the control in insects of physiological systems by hormones may not always involve tissue-specific hormones that force stereotypical responses in their target systems. Instead, there may exist in the extracellular fluid a continuous broadcast of information in the form of a chemical language to which some or all parts of the body continuously respond on a moment-to-moment basis, and which ensures a more effective and efficient coordination of function than could be achieved otherwise. PMID:12077163

  17. Morphological characterization of the nymphs Rhipicephalus sanguineus ticks (Latreille, 1806) (Acari: Ixodidae). Description of the testes, integument, Malpighian tubules, and midgut on the detachment day.

    PubMed

    De Oliveira, Patrícia Rosa; Calligaris, Izabela Braggião; Roma, Gislaine Cristina; Bechara, Gervásio Henrique; Mathias, Maria Izabel Camargo

    2012-06-01

    This study presents the morpho-histological and histochemical characterization of the testes, integument, Malpighian tubules, and midgut of engorged Rhipicephalus sanguineus nymphs on the detachment day, showing the morphological and physiological characteristics to this phase in the life cycle of these individuals. The testis is constituted by germinative cells (only spermatogonia) with large, round-shaped and strongly stained nuclei which are organized into cysts by a thin layer of somatic cells. The integument consists of a cuticle subdivided into epicuticle (lipoprotein) and procuticle (glycoproteic), and a layer of epithelial cells which present glycolipoprotein elements. The procuticle presents two distinct regions: the exocuticle (next to the epicuticle) and the endocuticle (next to the epithelial layer). The Malpighian tubules present a simple epithelium with small flat and/or cubic cells, which form its wall and delimitates a lumen full of lipoprotein material. The midgut consists of an epithelial wall formed by two types of digestive cells, spent cells and empty digest cells, and by generative cells supported by a basal lamina and a thin layer of muscular tissue. This study described the main organs of engorged nymphs of R. sanguineus, to generate information that can help researchers to better understand the biology of these ectoparasites; which is fundamental for the development of compounds that are less aggressive to the environment. In addition, if the immature stages of the ticks are controlled, the number of adult ticks able to cause damages to the animals--and to the man as well--is also under control. PMID:22615106

  18. An X-ray microanalytical study on the effects of ouabain and N-ethyl maleimide on the elemental concentrations in Malpighian tubule cells of Locusta.

    PubMed

    Pivovarova, N; Anstee, J H; Bowler, K

    1994-01-01

    X-ray microanalysis was used to study elemental distribution in Malpighian tubule cells of Locusta migratoria and how these are affected by the replacement of bathing medium K+ with Rb+ and by inclusion of the transport inhibitors ouabain and n-ethyl maleimide (NEM) in standard (K+-containing) and Rb+-Ringer (K+-free) solutions. Incubation of tubules in standard Ringer containing 1mM ouabain dramatically affected the intracellular levels of K and Na. The intracellular K concentration fell and Na concentration increased in all regions studied. Despite this, a gradient of increasing K concentration from basal to apical cell surface was maintained. Ouabain also reduced the intracellular levels of Rb when applied in Rb+-Ringer. Cl and P levels were unaffected by ouabain treatment. Incubation in standard and Rb+-Ringer solutions containing 1 microM NEM caused a significant increase in intracellular K levels in all regions of the cell compared with that observed in the absence of NEM. Rb levels were little affected by NEM except in the apical cytoplasm and microvillar regions where they were significantly reduced compared with Rb+-Ringer controls. NEM effected a significant increase in cellular levels of Na under Rb+-Ringer conditions. Intracellular Cl and P were not significantly affected by NEM. These results are discussed in relation to proposed mechanisms for the transport of ions and water across this secretory epithelium, with particular emphasis on the role of K+ as the 'prime mover' in this process. PMID:7638499

  19. Neurohormones implicated in the control of Malpighian tubule secretion in plant sucking heteropterans: The stink bugs Acrosternum hilare and Nezara viridula.

    PubMed

    Coast, Geoffrey M; TeBrugge, Victoria A; Nachman, Ronald J; Lopez, Juan; Aldrich, Jeffrey R; Lange, Angela; Orchard, Ian

    2010-03-01

    Plant sucking heteropteran bugs feed regularly on small amounts of K(+)-rich plant material, in contrast to their hematophagous relatives which imbibe large volumes of Na(+)-rich blood. It was anticipated that this would be reflected in the endocrine control of Malpighian tubule (MT) secretion. To explore this, neuroendocrine factors known to influence MT secretion were tested on MT of the pentatomid plant sucking stink bugs, Acrosternum hilare and Nezara viridula, and the results compared with previously published data from Rhodnius prolixus. Serotonin had no effect on N. viridula MT, although it stimulates secretion by R. prolixus MT >1000-fold, and initiates a rapid diuresis to remove excess salt and water from the blood meal. Kinins had no effect on stink bug MT, but secretion was increased by Zoone-DH, a CRF-like peptide, although the response was a modest 2-3-fold acceleration compared with 1000-fold in R. prolixus. Native CAPA peptides, which have diuretic activity in dipteran flies, had antidiuretic activity in MT of the stink bug (Acrhi/Nezvi-CAPA-1 and -2), as previously shown with Rhopr-CAPA-2 in R. prolixus. The antidiuretic activity of Rhopr-CAPA-2 has been linked with terminating the rapid diuresis, but results with stink bugs suggest it is a general feature of heteropteran MT. PMID:19772880

  20. Whole-body distribution an Malpighian tubule transport of 2',5-dichloro-4'-nitrosalicylanilide (Bayer 73) and 3-trifluoromethyl-4-nitrophenol in larvae of the aquatic midge Chironomus tentans.

    PubMed

    Hansen, C R; Gauss, J D; Kawatski, J A

    1980-04-01

    1. Residues of the lampricides 14C-Bayer 73 (2',5-dichloro-4'-nitrosalicylanilide) and 14C-TFM (3-trifluoromethyl-4-nitrophenol) were absorbed from aqueous sublethal concn. by aquatic larvae of the midge Chironomus tentans. 2. Toxicant residues were widely distributed during early hours of exposure, but later and during a 24-h post-exposure period, they became concentrated in the trunk and intestinal tract; the posterior movement of Bayer 73 was more rapid than that of TFM. 3. During 4-h tests, Malpighian tubules of the chironomid actively transported Bayer 73 and TFM in vitro, and on a per tubule basis, more TFM was transported than Bayer 73. 4. Potassium cyanide inhibited tubule transport; serotonin had no effect. PMID:7415206

  1. A leucokinin mimic elicits aversive behavior in mosquito Aedes aegypti (L.) and inhibits the sugar taste neuron

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect kinins (leucokinins) are multifunctional peptides acting as neurohormones and neurotransmitters. In females of the mosquito vector Aedes aegypti (L.), aedeskinins are known to stimulate fluid secretion from the renal organs (Malpighian tubules) and hindgut contractions by activating a G prot...

  2. Fine-scale temperature fluctuation and modulation of Dirofilaria immitis larval development in Aedes aegypti.

    PubMed

    Ledesma, Nicholas; Harrington, Laura

    2015-04-15

    We evaluated degree-day predictions of Dirofilaria immitis development (HDU) under constant and fluctuating temperature treatments of equal average daily temperature. Aedes aegypti mosquitoes were infected with D. immitis microfilariae and parasite development was recorded at set time points in dissected mosquitoes. Time to L3 development in Malpighian tubules and detection in mosquito heads was shorter for larvae experiencing a daily regime of 19±9°C than larvae at constant 19°C; larval development rate in Malpighian tubules was slower in fluctuating regimes maintained above the 14°C developmental threshold than larvae under constant temperatures. We showed that hourly temperature modeling more accurately predicted D. immitis development to infective L3 stage. Development time differed between fluctuating and constant temperature treatments spanning the 14°C development threshold, implicating a physiological basis for these discrepancies. We conclude that average daily temperature models underestimate L3 development-and consequently dog heartworm transmission risk-at colder temperatures, and spatiotemporal models of D. immitis transmission risk should use hourly temperature data when analyzing high daily temperature ranges spanning 14°C. PMID:25747489

  3. Function-informed transcriptome analysis of Drosophila renal tubule

    PubMed Central

    Wang, Jing; Kean, Laura; Yang, Jingli; Allan, Adrian K; Davies, Shireen A; Herzyk, Pawel; Dow, Julian AT

    2004-01-01

    Background Comprehensive, tissue-specific, microarray analysis is a potent tool for the identification of tightly defined expression patterns that might be missed in whole-organism scans. We applied such an analysis to Drosophila melanogaster Malpighian (renal) tubule, a defined differentiated tissue. Results The transcriptome of the D. melanogaster Malpighian tubule is highly reproducible and significantly different from that obtained from whole-organism arrays. More than 200 genes are more than 10-fold enriched and over 1,000 are significantly enriched. Of the top 200 genes, only 18 have previously been named, and only 45% have even estimates of function. In addition, 30 transcription factors, not previously implicated in tubule development, are shown to be enriched in adult tubule, and their expression patterns respect precisely the domains and cell types previously identified by enhancer trapping. Of Drosophila genes with close human disease homologs, 50 are enriched threefold or more, and eight enriched 10-fold or more, in tubule. Intriguingly, several of these diseases have human renal phenotypes, implying close conservation of renal function across 400 million years of divergent evolution. Conclusions From those genes that are identifiable, a radically new view of the function of the tubule, emphasizing solute transport rather than fluid secretion, can be obtained. The results illustrate the phenotype gap: historically, the effort expended on a model organism has tended to concentrate on a relatively small set of processes, rather than on the spread of genes in the genome. PMID:15345053

  4. Altered stress fibers and integrin expression in the Malpighian epithelium of Drosophila type IV collagen mutants

    PubMed Central

    Kiss, András A.; Popovics, Nikoletta; Szabó, Gábor; Csiszár, Katalin; Mink, Mátyás

    2016-01-01

    Basement membranes (BMs) are highly specialized extracellular matrices (ECMs) that provide support and polarization cues for epithelial cells. Proper adhesion to the BM is pivotal in epithelial cell function and survival. Type IV collagens are the predominant components of all types of BMs, that form an irregular, polygonal lattice and serve as a scaffold for numerous other BM components and BM-associated cells. Mutations in the ubiquitous human BM components COL4A1 and COL4A2 cause a multisystem disorder involving nephropathy. Affected patients develop renal dysfunction and chronic kidney failure with or without hematuria. Mouse Col4a1 and Col4a2 mutants recapitulate the human symptoms. In vertebrates, excretion is accomplished by the kidneys and by the Malpighian tubules in insects, including the fruit fly Drosophila. Our present results with dominant, temperature-sensitive mutation of the Drosophila col4a1 gene demonstrate altered integrin expression and amplified effects of mechanical stress on the Malpighian epithelial cytoskeleton. PMID:27077087

  5. Altered stress fibers and integrin expression in the Malpighian epithelium of Drosophila type IV collagen mutants.

    PubMed

    Kiss, András A; Popovics, Nikoletta; Szabó, Gábor; Csiszár, Katalin; Mink, Mátyás

    2016-06-01

    Basement membranes (BMs) are highly specialized extracellular matrices (ECMs) that provide support and polarization cues for epithelial cells. Proper adhesion to the BM is pivotal in epithelial cell function and survival. Type IV collagens are the predominant components of all types of BMs, that form an irregular, polygonal lattice and serve as a scaffold for numerous other BM components and BM-associated cells. Mutations in the ubiquitous human BM components COL4A1 and COL4A2 cause a multisystem disorder involving nephropathy. Affected patients develop renal dysfunction and chronic kidney failure with or without hematuria. Mouse Col4a1 and Col4a2 mutants recapitulate the human symptoms. In vertebrates, excretion is accomplished by the kidneys and by the Malpighian tubules in insects, including the fruit fly Drosophila. Our present results with dominant, temperature-sensitive mutation of the Drosophila col4a1 gene demonstrate altered integrin expression and amplified effects of mechanical stress on the Malpighian epithelial cytoskeleton. PMID:27077087

  6. Functional and immunohistochemical characterization of CCEae3a, a carboxylesterase associated with temephos resistance in the major arbovirus vectors Aedes aegypti and Ae. albopictus.

    PubMed

    Grigoraki, Linda; Balabanidou, Vassileia; Meristoudis, Christos; Miridakis, Antonis; Ranson, Hilary; Swevers, Luc; Vontas, John

    2016-07-01

    Temephos is a major organophosphate (OP) larvicide that has been used extensively for the control of Aedes albopictus and Aedes aegypti, the major vectors for viral diseases, such as dengue fever, zika and chikungunya. Resistance to temephos has been recently detected and associated with the upregulation of carboxylesterases (CCEs) through gene amplification, in both species. Here, we expressed the CCEae3a genes which showed the most striking up-regulation in resistant Aedes strains, using the baculovirus system. All CCEae3a variants encoded functional enzymes, with high activity and preference for p-nitrophenyl butyrate, a substrate that was shown capable to differentiate temephos resistant from susceptible Aedes larvae. Enzyme kinetic studies showed that CCEae3as from both Ae. aegypti and Ae. albopictus (CCEae3a_aeg and CCEae3a_alb, respectively) strongly interact with temephos oxon and slowly released the OP molecule, indicating a sequestration resistance mechanism. No difference was detected between resistant and susceptible CCEae3a_aeg variants (CCEae3a_aegR and CCEae3a_aegS, respectively), indicating that previously reported polymorphism is unlikely to play a role in temephos resistance. HPLC/MS showed that CCEae3as were able to metabolize temephos oxon to the temephos monoester [(4-hydroxyphenyl) sulfanyl] phenyl O,O-dimethylphosphorothioate. Western blot and immunolocalization studies, based on a specific antibody raised against the CCEae3a_alb showed that the enzyme is expressed at higher levels in resistant insects, primarily in malpighian tubules (MT) and nerve tissues. PMID:27180726

  7. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase.

    PubMed

    Mazzalupo, Stacy; Isoe, Jun; Belloni, Virginia; Scaraffia, Patricia Y

    2016-01-01

    To better understand the mechanisms responsible for the success of female mosquitoes in their disposal of excess nitrogen, we investigated the role of alanine aminotransferase (ALAT) in blood-fed Aedes aegypti. Transcript and protein levels from the 2 ALAT genes were analyzed in sucrose- and blood-fed A. aegypti tissues. ALAT1 and ALAT2 exhibit distinct expression patterns in tissues during the first gonotrophic cycle. Injection of female mosquitoes with either double-stranded RNA (dsRNA)-ALAT1 or dsRNA ALAT2 significantly decreased mRNA and protein levels of ALAT1 or ALAT2 in fat body, thorax, and Malpighian tubules compared with dsRNA firefly luciferase-injected control mosquitoes. The silencing of either A. aegypti ALAT1 or ALAT2 caused unexpected phenotypes such as a delay in blood digestion, a massive accumulation of uric acid in the midgut posterior region, and a significant decrease of nitrogen waste excretion during the first 48 h after blood feeding. Concurrently, the expression of genes encoding xanthine dehydrogenase and ammonia transporter (Rhesus 50 glycoprotein) were significantly increased in tissues of both ALAT1- and ALAT2-deficient females. Moreover, perturbation of ALAT1 and ALAT2 in the female mosquitoes delayed oviposition and reduced egg production. These novel findings underscore the efficient mechanisms that blood-fed mosquitoes use to avoid ammonia toxicity and free radical damage.-Mazzalupo, S., Isoe, J., Belloni, V., Scaraffia, P. Y. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase. PMID:26310269

  8. Some factors affecting Malpighian tubule fluid secretion and transepithelial potential in Locusta migratoria L.

    PubMed

    Anstee, J H; Bell, D M; Hyde, D

    1980-02-15

    Both fluid secretion and transepithelial potential were stimulated by cAMP. Fluid secretion was unaffected by 5-HT over the concentration range 10(-8)-10(-4) M. The presence of ouabain in the bathing medium effected a decrease in transepithelial potential. PMID:6245909

  9. Distal Convoluted Tubule

    PubMed Central

    Ellison, David H.

    2014-01-01

    The distal convoluted tubule is the nephron segment that lies immediately downstream of the macula densa. Although short in length, the distal convoluted tubule plays a critical role in sodium, potassium, and divalent cation homeostasis. Recent genetic and physiologic studies have greatly expanded our understanding of how the distal convoluted tubule regulates these processes at the molecular level. This article provides an update on the distal convoluted tubule, highlighting concepts and pathophysiology relevant to clinical practice. PMID:24855283

  10. Leucokinin mimetic elicits aversive behavior in mosquito Aedes aegypti (L.) and inhibits the sugar taste neuron.

    PubMed

    Kwon, Hyeogsun; Ali Agha, Moutaz; Smith, Ryan C; Nachman, Ronald J; Marion-Poll, Frédéric; Pietrantonio, Patricia V

    2016-06-21

    Insect kinins (leucokinins) are multifunctional peptides acting as neurohormones and neurotransmitters. In females of the mosquito vector Aedes aegypti (L.), aedeskinins are known to stimulate fluid secretion from the renal organs (Malpighian tubules) and hindgut contractions by activating a G protein-coupled kinin receptor designated "Aedae-KR." We used protease-resistant kinin analogs 1728, 1729, and 1460 to evaluate their effects on sucrose perception and feeding behavior. In no-choice feeding bioassays (capillary feeder and plate assays), the analog 1728, which contains α-amino isobutyric acid, inhibited females from feeding on sucrose. It further induced quick fly-away or walk-away behavior following contact with the tarsi and the mouthparts. Electrophysiological recordings from single long labellar sensilla of the proboscis demonstrated that mixing the analog 1728 at 1 mM with sucrose almost completely inhibited the detection of sucrose. Aedae-KR was immunolocalized in contact chemosensory neurons in prothoracic tarsi and in sensory neurons and accessory cells of long labellar sensilla in the distal labellum. Silencing Aedae-KR by RNAi significantly reduced gene expression and eliminated the feeding-aversion behavior resulting from contact with the analog 1728, thus directly implicating the Aedae-KR in the aversion response. To our knowledge, this is the first report that kinin analogs modulate sucrose perception in any insect. The aversion to feeding elicited by analog 1728 suggests that synthetic molecules targeting the mosquito Aedae-KR in the labellum and tarsi should be investigated for the potential to discover novel feeding deterrents of mosquito vectors. PMID:27274056

  11. Nanocapillarity in fullerene tubules

    NASA Astrophysics Data System (ADS)

    Pederson, Mark R.; Broughton, Jeremy Q.

    1992-11-01

    Fullerene tubules are shown to be highly polarizable ``molecular straws'' capable of ingesting dipolar molecules. Local-density-functional calculations on HF molecules within a finite-length tubule, of size 144 atoms, demonstrate this effect. The energy of incarceration is several times the thermal ambient at room temperature. These calculations, now feasible on desktop workstations, open the way to the study of nanoscale capillarity and to, perhaps, precise control over shielding of specific ``guest'' compounds from external electric and magnetic fields.

  12. Comprehensive Immunolocalization Studies of a Putative Serotonin Receptor from the Alimentary Canal of Aedes aegypti Larvae Suggest Its Diverse Roles in Digestion and Homeostasis

    PubMed Central

    Petrova, Adelina; Moffett, David Franklin

    2016-01-01

    Serotonin regulates key processes including digestion and homeostasis in insects. Serotonin effects are mediated by serotonin receptors that transduce information through initiation of second messenger signaling pathways. Lack of information on serotonin receptors associated with the alimentary canal impedes the understanding of the serotonergic role in insect physiology. To address this void, the present study has cloned and identified a putative serotonin receptor (hereafter AaSeR-1) from the alimentary canal of Aedes aegypti (yellow fever mosquito) larvae. In addition to in-silico analyses of AaSeR-1 primary sequence, immunohistochemical investigations were carried out to elucidate receptor expression patterns. Specific AaSeR-1 immunofluorescence was detected in the caeca, the mid- and hindgut, including the Malpighian tubules. These findings point out not only receptor ubiquitous nature but also its involvement in regulation of different stages of nutrient processing and homeostasis. Furthermore, AaSeR-1 may mediate an array of effects through its differential expression at various cell compartments. While AaSeR-1 specific immunofluorescence was depicted in the nucleus and nucleolus of principal cells of the anterior midgut, in the posterior, analyses suggest receptor association with the plasma membrane of both principal and regenerative cells. In addition, AaSeR-1 immunofluorescence was also found in some enteroendocrine cells and in both circular and longitudinal muscles that innervate the alimentary canal. Overall, immunohistochemical analyses of AaSeR-1 expression indicate that this receptor exercises multiple roles in digestion- and homeostasis-related mechanisms. PMID:26808995

  13. Comprehensive Immunolocalization Studies of a Putative Serotonin Receptor from the Alimentary Canal of Aedes aegypti Larvae Suggest Its Diverse Roles in Digestion and Homeostasis.

    PubMed

    Petrova, Adelina; Moffett, David Franklin

    2016-01-01

    Serotonin regulates key processes including digestion and homeostasis in insects. Serotonin effects are mediated by serotonin receptors that transduce information through initiation of second messenger signaling pathways. Lack of information on serotonin receptors associated with the alimentary canal impedes the understanding of the serotonergic role in insect physiology. To address this void, the present study has cloned and identified a putative serotonin receptor (hereafter AaSeR-1) from the alimentary canal of Aedes aegypti (yellow fever mosquito) larvae. In addition to in-silico analyses of AaSeR-1 primary sequence, immunohistochemical investigations were carried out to elucidate receptor expression patterns. Specific AaSeR-1 immunofluorescence was detected in the caeca, the mid- and hindgut, including the Malpighian tubules. These findings point out not only receptor ubiquitous nature but also its involvement in regulation of different stages of nutrient processing and homeostasis. Furthermore, AaSeR-1 may mediate an array of effects through its differential expression at various cell compartments. While AaSeR-1 specific immunofluorescence was depicted in the nucleus and nucleolus of principal cells of the anterior midgut, in the posterior, analyses suggest receptor association with the plasma membrane of both principal and regenerative cells. In addition, AaSeR-1 immunofluorescence was also found in some enteroendocrine cells and in both circular and longitudinal muscles that innervate the alimentary canal. Overall, immunohistochemical analyses of AaSeR-1 expression indicate that this receptor exercises multiple roles in digestion- and homeostasis-related mechanisms. PMID:26808995

  14. The response of claudin-like transmembrane septate junction proteins to altered environmental ion levels in the larval mosquito Aedes aegypti.

    PubMed

    Jonusaite, Sima; Kelly, Scott P; Donini, Andrew

    2016-07-01

    Septate junctions (SJs) occlude the paracellular pathway and function as paracellular diffusion barriers within invertebrate epithelia. However, integral components of SJs and their contribution to barrier properties have received considerably less attention than those of vertebrate occluding junctions. In arthropods, SJ proteins have only been identified in Drosophila and among these are three integral claudin-like proteins, Megatrachea (Mega), Sinuous (Sinu) and Kune-kune (Kune), as well as a receptor-like transmembrane SJ protein known as Neurexin IV (Nrx IV). In this study, mega, sinu, kune and nrx IV are identified and characterized in aquatic larvae of the mosquito Aedes aegypti and a role for these proteins in ionoregulatory homeostasis is considered. Transcripts encoding Mega, Sinu, Kune and Nrx IV were found in iono/osmoregulatory tissues such as the midgut, Malpighian tubules, hindgut and anal papillae, but abundance was greater in the hindgut and anal papillae. Using immunohistochemical and western blot analysis it was found that Kune localized to the regions of intercellular contact between epithelial cells of the rectum and posterior midgut and in the apical membrane domain of the syncytial epithelium of anal papillae. To investigate a potential role for integral SJ proteins in larval A. aegypti iono/osmoregulation, abundance was examined in animals reared in freshwater or brackish water (30 % seawater). In iono/osmoregulatory epithelia, larvae exhibited tissue-specific alterations in mega mRNA and Kune protein abundance, but not sinu or nrx IV mRNA. These studies provide a first look at the potential contribution of integral SJ components to iono/osmoregulatory homeostasis in an aquatic invertebrate. PMID:27004691

  15. The cell adhesion molecule Fasciclin2 regulates brush border length and organization in Drosophila renal tubules.

    PubMed

    Halberg, Kenneth A; Rainey, Stephanie M; Veland, Iben R; Neuert, Helen; Dornan, Anthony J; Klämbt, Christian; Davies, Shireen-Anne; Dow, Julian A T

    2016-01-01

    Multicellular organisms rely on cell adhesion molecules to coordinate cell-cell interactions, and to provide navigational cues during tissue formation. In Drosophila, Fasciclin 2 (Fas2) has been intensively studied due to its role in nervous system development and maintenance; yet, Fas2 is most abundantly expressed in the adult renal (Malpighian) tubule rather than in neuronal tissues. The role Fas2 serves in this epithelium is unknown. Here we show that Fas2 is essential to brush border maintenance in renal tubules of Drosophila. Fas2 is dynamically expressed during tubule morphogenesis, localizing to the brush border whenever the tissue is transport competent. Genetic manipulations of Fas2 expression levels impact on both microvilli length and organization, which in turn dramatically affect stimulated rates of fluid secretion by the tissue. Consequently, we demonstrate a radically different role for this well-known cell adhesion molecule, and propose that Fas2-mediated intermicrovillar homophilic adhesion complexes help stabilize the brush border. PMID:27072072

  16. The cell adhesion molecule Fasciclin2 regulates brush border length and organization in Drosophila renal tubules

    PubMed Central

    Halberg, Kenneth A.; Rainey, Stephanie M.; Veland, Iben R.; Neuert, Helen; Dornan, Anthony J.; Klämbt, Christian; Davies, Shireen-Anne; Dow, Julian A. T.

    2016-01-01

    Multicellular organisms rely on cell adhesion molecules to coordinate cell–cell interactions, and to provide navigational cues during tissue formation. In Drosophila, Fasciclin 2 (Fas2) has been intensively studied due to its role in nervous system development and maintenance; yet, Fas2 is most abundantly expressed in the adult renal (Malpighian) tubule rather than in neuronal tissues. The role Fas2 serves in this epithelium is unknown. Here we show that Fas2 is essential to brush border maintenance in renal tubules of Drosophila. Fas2 is dynamically expressed during tubule morphogenesis, localizing to the brush border whenever the tissue is transport competent. Genetic manipulations of Fas2 expression levels impact on both microvilli length and organization, which in turn dramatically affect stimulated rates of fluid secretion by the tissue. Consequently, we demonstrate a radically different role for this well-known cell adhesion molecule, and propose that Fas2-mediated intermicrovillar homophilic adhesion complexes help stabilize the brush border. PMID:27072072

  17. Lipid tubule growth by osmotic pressure

    PubMed Central

    Rangamani, Padmini; Zhang, Di; Oster, George; Shen, Amy Q.

    2013-01-01

    We present here a procedure for growing lipid tubules in vitro. This method allows us to grow tubules of consistent shape and structure, and thus can be a useful tool for nano-engineering applications. There are three stages during the tubule growth process: initiation, elongation and termination. Balancing the forces that act on the tubule head shows that the growth of tubules during the elongation phase depends on the balance between osmotic pressure and the viscous drag exerted on the membrane from the substrate and the external fluid. Using a combination of mathematical modelling and experiment, we identify the key forces that control tubule growth during the elongation phase. PMID:24004559

  18. Functional characterization of aquaporins and aquaglyceroporins of the yellow fever mosquito, Aedes aegypti

    PubMed Central

    Drake, Lisa L.; Rodriguez, Stacy D.; Hansen, Immo A.

    2015-01-01

    After taking vertebrate blood, female mosquitoes quickly shed excess water and ions while retaining and concentrating the mostly proteinaceous nutrients. Aquaporins (AQPs) are an evolutionary conserved family of membrane transporter proteins that regulate the flow of water and in some cases glycerol and other small molecules across cellular membranes. In a previous study, we found six putative AQP genes in the genome of the yellow fever mosquito, Ae. aegypti, and demonstrated the involvement of three of them in the blood meal-induced diuresis. Here we characterized AQP expression in different tissues before and after a blood meal, explored the substrate specificity of AQPs expressed in the Malpighian tubules and performed RNAi-mediated knockdown and tested for changes in mosquito desiccation resistance. We found that AQPs are generally down-regulated 24 hrs after a blood meal. Ae. aegypti AQP 1 strictly transports water, AQP 2 and 5 demonstrate limited solute transport, but primarily function as water transporters. AQP 4 is an aquaglyceroporin with multiple substrates. Knockdown of AQPs expressed in the MTs increased survival of Ae. aegypti under dry conditions. We conclude that Malpighian tubules of adult female yellow fever mosquitoes utilize three distinct AQPs and one aquaglyceroporin in their osmoregulatory functions. PMID:25589229

  19. Kinesin 1 Drives Autolysosome Tubulation.

    PubMed

    Du, Wanqing; Su, Qian Peter; Chen, Yang; Zhu, Yueyao; Jiang, Dong; Rong, Yueguang; Zhang, Senyan; Zhang, Yixiao; Ren, He; Zhang, Chuanmao; Wang, Xinquan; Gao, Ning; Wang, Yanfeng; Sun, Lingfei; Sun, Yujie; Yu, Li

    2016-05-23

    Autophagic lysosome reformation (ALR) plays an important role in maintaining lysosome homeostasis. During ALR, lysosomes are reformed by recycling lysosomal components from autolysosomes. The most noticeable step of ALR is autolysosome tubulation, but it is currently unknown how the process is regulated. Here, using an approach combining in vivo studies and in vitro reconstitution, we found that the kinesin motor protein KIF5B is required for autolysosome tubulation and that KIF5B drives autolysosome tubulation by pulling on the autolysosomal membrane. Furthermore, we show that KIF5B directly interacts with PtdIns(4,5)P2. Kinesin motors are recruited and clustered on autolysosomes via interaction with PtdIns(4,5)P2 in a clathrin-dependent manner. Finally, we demonstrate that clathrin promotes formation of PtdIns(4,5)P2-enriched microdomains, which are required for clustering of KIF5B. Our study reveals a mechanism by which autolysosome tubulation was generated. PMID:27219061

  20. Hypotonicity Stimulates Potassium Flux through the WNK-SPAK/OSR1 Kinase Cascade and the Ncc69 Sodium-Potassium-2-Chloride Cotransporter in the Drosophila Renal Tubule*

    PubMed Central

    Wu, Yipin; Schellinger, Jeffrey N.; Huang, Chou-Long; Rodan, Aylin R.

    2014-01-01

    The ability to osmoregulate is fundamental to life. Adult Drosophila melanogaster maintain hemolymph osmolarity within a narrow range. Osmolarity modulates transepithelial ion and water flux in the Malpighian (renal) tubules of the fly, which are in direct contact with hemolymph in vivo, but the mechanisms causing increased transepithelial flux in response to hypotonicity are unknown. Fly renal tubules secrete a KCl-rich fluid. We have previously demonstrated a requirement for Ncc69, the fly sodium-potassium-2-chloride cotransporter (NKCC), in tubule K+ secretion. Mammalian NKCCs are regulated by a kinase cascade consisting of the with-no-lysine (WNK) and Ste20-related proline/alanine-rich (SPAK)/oxidative stress response (OSR1) kinases. Here, we show that decreasing Drosophila WNK activity causes a reduction in K+ flux. Similarly, knocking down the SPAK/OSR1 homolog fray also decreases K+ flux. We demonstrate that a hierarchical WNK-Fray signaling cascade regulates K+ flux through Ncc69, because (i) a constitutively active Fray mutant rescues the wnk knockdown phenotype, (ii) Fray directly phosphorylates Ncc69 in vitro, and (iii) the effect of wnk and fray knockdown is abolished in Ncc69 mutants. The stimulatory effect of hypotonicity on K+ flux is absent in wnk, fray, or Ncc69 mutant tubules, suggesting that the Drosophila WNK-SPAK/OSR1-NKCC cascade is an essential molecular pathway for osmoregulation, through its effect on transepithelial ion flux and fluid generation by the renal tubule. PMID:25086033

  1. Renin expression in renal proximal tubule.

    PubMed Central

    Moe, O W; Ujiie, K; Star, R A; Miller, R T; Widell, J; Alpern, R J; Henrich, W L

    1993-01-01

    Angiotensinogen, angiotensin-converting enzyme, and renin constitute the components of the renin-angiotensin system. The mammalian renal proximal tubule contains angiotensinogen, angiotensin-converting enzyme, and angiotensin receptors. Previous immunohistochemical studies describing the presence of renin in the proximal tubule could not distinguish synthesized renin from renin trapped from the glomerular filtrate. In the present study, we examined the presence of renin activity and mRNA in rabbit proximal tubule cells in primary culture and renin mRNA in microdissected proximal tubules. Renin activity was present in lysates of proximal tubule cells in primary culture. Cellular renin content in cultured proximal tubule cells was increased by incubation with 10(-5) M isoproterenol and 10(-5) M forskolin by 150 and 110%, respectively. In addition, renin transcripts were detected in poly(A)+ RNA from cultured proximal tubule cells by RNA blots under high stringency conditions. In microdissected tubules from normal rats, renin mRNA was not detectable with reverse transcription and polymerase chain reaction. However, in tubules from rats administered the angiotensinogen-converting-enzyme inhibitor, enalapril, renin was easily detected in the S2 segment of the proximal tubule. We postulate the existence of a local renin-angiotensin system that enables the proximal tubule to generate angiotensin II, thereby providing an autocrine system that could locally modulate NaHCO3 and NaCl absorption. Images PMID:7680667

  2. Who regenerates the kidney tubule?

    PubMed

    Kramann, Rafael; Kusaba, Tetsuro; Humphreys, Benjamin D

    2015-06-01

    The kidney possesses profound regenerative potential and in some cases can recover completely 'restitutio at integrum' following an acute kidney injury (AKI). Emerging evidence strongly suggests that sometimes repair is incomplete, however, and, in this situation, an episode of AKI leads to future chronic kidney disease (CKD). Understanding the tubular response after AKI will shed light on the relationship between incomplete repair and future risk of CKD. The first repair phase after AKI is characterized by robust proliferation of epithelial cells in the proximal tubule. The exact source of these proliferating cells has been a source of controversy for the last decade. While nearly everyone now agrees that reparative cells arise within the proximal tubule, there is disagreement about whether all surviving cells possess an equivalent repair capacity through dedifferentiation, or alternatively whether a pre-existing intratubular stem cell population [so-called scattered tubular cells (STC)] is responsible for repair. This review will summarize the evidence on both sides of this issue and will discuss very recent genetic fate-tracing data that strongly points against the existence of intratubular stem cells but rather indicates that terminally differentiated proximal tubule epithelial cells undergo dedifferentiation upon injury to replace lost neighboring tubular epithelial cells through proliferative self-duplication. This new evidence includes data clearly indicating that STC are not committed tubular stem cells but instead represent individual dedifferentiated tubular epithelial cells that transiently express putative stem cell markers. PMID:25155054

  3. Neurohormones implicated in the control of Malpighian tubule secretion in plant sucking Heteropterans: The stink bugs Acrosternum hilare and Nezara viridula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant sucking heteropteran bugs feed regularly on small amounts of K+rich plant material, in contrast to their hematophagous relatives which imbibe large volumes of Na+-rich blood. It was anticipated that this would be reflected in the endocrine control of MT secretion. To explore this, neuroendocri...

  4. Desiccation resistance in Aedes aegypti and Aedes albopictus eggs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Causative influences that impact the separation of Aedes aegypti and Aedes albopictus populations in different geographic areas were determined. The eggs of Ae. albopictus and Ae. aegypti collected from McAllen and Brownsville, Texas, and laboratory populations of these two species were subjected t...

  5. Invasion of dentinal tubules by oral bacteria.

    PubMed

    Love, R M; Jenkinson, H F

    2002-01-01

    Bacterial invasion of dentinal tubules commonly occurs when dentin is exposed following a breach in the integrity of the overlying enamel or cementum. Bacterial products diffuse through the dentinal tubule toward the pulp and evoke inflammatory changes in the pulpo-dentin complex. These may eliminate the bacterial insult and block the route of infection. Unchecked, invasion results in pulpitis and pulp necrosis, infection of the root canal system, and periapical disease. While several hundred bacterial species are known to inhabit the oral cavity, a relatively small and select group of bacteria is involved in the invasion of dentinal tubules and subsequent infection of the root canal space. Gram-positive organisms dominate the tubule microflora in both carious and non-carious dentin. The relatively high numbers of obligate anaerobes present-such as Eubacterium spp., Propionibacterium spp., Bifidobacterium spp., Peptostreptococcus micros, and Veillonella spp.-suggest that the environment favors growth of these bacteria. Gram-negative obligate anaerobic rods, e.g., Porphyromonas spp., are less frequently recovered. Streptococci are among the most commonly identified bacteria that invade dentin. Recent evidence suggests that streptococci may recognize components present within dentinal tubules, such as collagen type I, which stimulate bacterial adhesion and intra-tubular growth. Specific interactions of other oral bacteria with invading streptococci may then facilitate the invasion of dentin by select bacterial groupings. An understanding the mechanisms involved in dentinal tubule invasion by bacteria should allow for the development of new control strategies, such as inhibitory compounds incorporated into oral health care products or dental materials, which would assist in the practice of endodontics. PMID:12097359

  6. Bioengineered kidney tubules efficiently excrete uremic toxins

    PubMed Central

    Jansen, J.; Fedecostante, M.; Wilmer, M. J.; Peters, J. G.; Kreuser, U. M.; van den Broek, P. H.; Mensink, R. A.; Boltje, T. J.; Stamatialis, D.; Wetzels, J. F.; van den Heuvel, L. P.; Hoenderop, J. G.; Masereeuw, R.

    2016-01-01

    The development of a biotechnological platform for the removal of waste products (e.g. uremic toxins), often bound to proteins in plasma, is a prerequisite to improve current treatment modalities for patients suffering from end stage renal disease (ESRD). Here, we present a newly designed bioengineered renal tubule capable of active uremic toxin secretion through the concerted action of essential renal transporters, viz. organic anion transporter-1 (OAT1), breast cancer resistance protein (BCRP) and multidrug resistance protein-4 (MRP4). Three-dimensional cell monolayer formation of human conditionally immortalized proximal tubule epithelial cells (ciPTEC) on biofunctionalized hollow fibers with maintained barrier function was demonstrated. Using a tailor made flow system, the secretory clearance of human serum albumin-bound uremic toxins, indoxyl sulfate and kynurenic acid, as well as albumin reabsorption across the renal tubule was confirmed. These functional bioengineered renal tubules are promising entities in renal replacement therapies and regenerative medicine, as well as in drug development programs. PMID:27242131

  7. High Yield Synthesis of Bucky Tubules and Bucky Onions

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoping; Wang, Youwen; Li, Wenzhu; Wenzhou, Li

    1994-04-01

    The bucky tubules and bucky onions are synthesized in macroscopic quantity with high yield by modified Kratschmer-Lamb-Fostiropoulos-Huffman method. Besides ordinary concentric bucky tubules, also are observed abnormal nonconcentric multilayer graphitic tubules with varying layer spacings. The curved graphitic tubules are observed, showing the tendency to form torus. Under appropriate helium pressure, about half of the synthesized product is the multi-shell bucky onions, polyhedral in shape in accord with the theoretical calculation.

  8. Tissue engineering of a bioartificial renal tubule.

    PubMed

    MacKay, S M; Funke, A J; Buffington, D A; Humes, H D

    1998-01-01

    Development of a bioartificial renal tubule with a confluent monolayer of renal epithelial cells supported on a permeable synthetic surface may be the first step to further optimization of renal substitution therapy currently used with hemodialysis or hemofiltration. Madin-Darby canine kidney cells, a permanent renal epithelial cell line, were seeded into the lumen of single hollow fibers. Functional confluence of the cells was demonstrated by the recovery of intraluminally perfused 14C-inulin that averaged >98.9% in the cell lined units vs <7.4% in the control noncell hollow fibers during identical pressure and flow conditions. The baseline absolute fluid transport rate averaged 1.4+/-0.4 microl/30 min. To test the dependency of fluid flux with oncotic and osmotic pressure differences across the bioartificial tubule, albumin was added to the extracapillary space, followed by the addition of ouabain, an inhibitor of Na+K+ adenosine triphosphatase, the enzyme responsible for active transport across the renal epithelium. Addition of albumin resulted in a significant increase in volume transport to 4.5+/-1.0 microl/30 min. Addition of ouabain inhibited transport back to baseline levels of 2.1+/-0.4 microl/30 min. These results are the first demonstration that renal epithelial cells have been grown successfully as a confluent monolayer along a hollow fiber, and exhibit functional transport capabilities. The next steps in constructing a bioartificial renal tubule successfully are to develop a multi-fiber bioreactor with primary renal proximal tubule cells that maintain not only transport properties but also differentiated metabolic and endocrine functions, including glucose and ammonia production, and the conversion of vitamin D3 to a more active derivative. A renal tubule device may add critical renal functional components not currently substituted for, thereby improving the treatment regimens for patients with acute and chronic renal failure. PMID:9617948

  9. Severity and Frequency of Proximal Tubule Injury Determines Renal Prognosis.

    PubMed

    Takaori, Koji; Nakamura, Jin; Yamamoto, Shinya; Nakata, Hirosuke; Sato, Yuki; Takase, Masayuki; Nameta, Masaaki; Yamamoto, Tadashi; Economides, Aris N; Kohno, Kenji; Haga, Hironori; Sharma, Kumar; Yanagita, Motoko

    2016-08-01

    AKI increases the risk of developing CKD, but the mechanisms linking AKI to CKD remain unclear. Because proximal tubule injury is the mainstay of AKI, we postulated that proximal tubule injury triggers features of CKD. We generated a novel mouse model to induce proximal tubule-specific adjustable injury by inducing the expression of diphtheria toxin (DT) receptor with variable prevalence in proximal tubules. Administration of high-dose DT in mice expressing the DT receptor consistently caused severe proximal tubule-specific injury associated with interstitial fibrosis and reduction of erythropoietin production. Mild proximal tubule injury from a single injection of low-dose DT triggered reversible fibrosis, whereas repeated mild injuries caused sustained interstitial fibrosis, inflammation, glomerulosclerosis, and atubular glomeruli. DT-induced proximal tubule-specific injury also triggered distal tubule injury. Furthermore, injured tubular cells cocultured with fibroblasts stimulated induction of extracellular matrix and inflammatory genes. These results support the existence of proximal-distal tubule crosstalk and crosstalk between tubular cells and fibroblasts. Overall, our data provide evidence that proximal tubule injury triggers several features of CKD and that the severity and frequency of proximal tubule injury determines the progression to CKD. PMID:26701981

  10. Update on nerve repair by biological tubulization

    PubMed Central

    2014-01-01

    Many surgical techniques are available for bridging peripheral nerve defects. Autologous nerve grafts are the current gold standard for most clinical conditions. In selected cases, alternative types of conduits can be used. Although most efforts are today directed towards the development of artificial synthetic nerve guides, the use of non-nervous autologous tissue-based conduits (biological tubulization) can still be considered a valuable alternative to nerve autografts. In this paper we will overview the advancements in biological tubulization of nerve defects, with either mono-component or multiple-component autotransplants, with a special focus on the use of a vein segment filled with skeletal muscle fibers, a technique that has been widely investigated in our laboratory and that has already been successfully introduced in the clinical practice. PMID:24606921

  11. Update on nerve repair by biological tubulization.

    PubMed

    Geuna, Stefano; Tos, Pierluigi; Titolo, Paolo; Ciclamini, Davide; Beningo, Teresa; Battiston, Bruno

    2014-01-01

    Many surgical techniques are available for bridging peripheral nerve defects. Autologous nerve grafts are the current gold standard for most clinical conditions. In selected cases, alternative types of conduits can be used. Although most efforts are today directed towards the development of artificial synthetic nerve guides, the use of non-nervous autologous tissue-based conduits (biological tubulization) can still be considered a valuable alternative to nerve autografts. In this paper we will overview the advancements in biological tubulization of nerve defects, with either mono-component or multiple-component autotransplants, with a special focus on the use of a vein segment filled with skeletal muscle fibers, a technique that has been widely investigated in our laboratory and that has already been successfully introduced in the clinical practice. PMID:24606921

  12. Morphological instability of whiskers, pores, and tubules

    NASA Astrophysics Data System (ADS)

    Kirill, Dimitri Jay

    1999-11-01

    A thin, stressed solid cylinder, a whisker, is subject to mass transport by curvature and elastic-stress-driven surface diffusion. The stability of the cylindrical surface is examined using linear stability theory. It is found that the applied stress leads to a greater range of unstable wavenumbers, and hence is destabilizing. The presence of elastic strains can excite non-axisymmetric modes, which, under certain conditions, are preferred and can give rise to helical surfaces. In addition, asymptotic formulas for growth rate in the limit of long and short wavelengths are found. A possible experiment is proposed which, if undertaken, should reveal the helical instability. The linear stability analysis is then extended to the case of cylindrical pore channels and hollow cylindrical tubules. In both cases, results similar to the whisker are found---increased applied stress leads to a greater range of unstable wavenumbers. For both the pore and tubule geometries, the dominant modes are axisymmetric for any value of applied stress; this contrasts with the solid whisker results. Since the tubule geometry consists of an inner and outer surface, there is a phase relationship between the two surface perturbations. The most dangerous eigenmode can exhibit either in-phase (sinuous) or 180° out-of-phase (varicose) perturbations, depending on the value of applied stress. Furthermore, there is a critical value of applied stress below which the most dangerous mode is varicose, and above which it is sinuous. Lastly, asymptotic formulas for growth rate are obtained in the limit of a thin-walled tubule. These results compare favorably to work done on stressed lamellar composites.

  13. BIN1 regulates dynamic t-tubule membrane.

    PubMed

    Fu, Ying; Hong, TingTing

    2016-07-01

    Cardiac transverse tubules (t-tubules) are specific membrane organelles critical in calcium signaling and excitation-contraction coupling required for beat-to-beat heart contraction. T-tubules are highly branched and form an interconnected network that penetrates the myocyte interior to form junctions with the sarcoplasmic reticulum. T-tubules are selectively enriched with specific ion channels and proteins crucial in calcium transient development necessary in excitation-contraction coupling, thus t-tubules are a key component of cardiac myocyte function. In this review, we focus primarily on two proteins concentrated within the t-tubular network, the L-type calcium channel (LTCC) and associated membrane anchor protein, bridging integrator 1 (BIN1). Here, we provide an overview of current knowledge in t-tubule morphology, composition, microdomains, as well as the dynamics of the t-tubule network. Secondly, we highlight multiple aspects of BIN1-dependent t-tubule function, which includes forward trafficking of LTCCs to t-tubules, LTCC clustering at t-tubule surface, microdomain organization and regulation at t-tubule membrane, and the formation of a slow diffusion barrier within t-tubules. Lastly, we describe progress in characterizing how acquired human heart failure can be attributed to abnormal BIN1 transcription and associated t-tubule remodeling. Understanding BIN1-regulated cardiac t-tubule biology in human heart failure management has the dual benefit of promoting progress in both biomarker development and therapeutic target identification. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel. PMID:26578114

  14. Detection and measurement of tubulitis in renal allograft rejection

    NASA Astrophysics Data System (ADS)

    Hiller, John B.; Chen, Qi; Jin, Jesse S.; Wang, Yung; Yong, James L. C.

    1997-04-01

    Tubulitis is one of the most reliable signs of acute renal allograft rejection. It occurs when mononuclear cells are localized between the lining tubular epithelial cells with or without disruption of the tubular basement membrane. It has been found that tubulitis takes place predominantly in the regions of the distal convoluted tubules and the cortical collecting system. The image processing tasks are to find the tubule boundaries and to find the relative location of the lymphocytes and epithelial cells and tubule boundaries. The requirement for accuracy applies to determining the relative locations of the lymphocytes and the tubule boundaries. This paper will show how the different sizes and grey values of the lymphocytes and epithelial cells simplify their identification and location. Difficulties in finding the tubule boundaries image processing will be illustrated. It will be shown how proximate location of epithelial cells and the tubule boundary leads to distortion in determination of the calculated boundary. However, in tubulitis the lymphocytes and the tubule boundaries are proximate.In these cases the tubule boundary is adequately resolved and the image processing is satisfactory to determining relativity in location. An adaptive non-linear anisotropic diffusion process is presented for image filtering and segmentation. Multi-layer analysis is used to extract lymphocytes and tubulitis from images. This paper will discuss grading of tissue using the Banff system. The ability to use computer to use computer processing will be argued as obviating problems of reproducability of values for this classification. This paper will also feature discussion of alternative approaches to image processing and provide an assessment of their capability for improving the identification of the tubule boundaries.

  15. Coupled water transport by rat proximal tubule.

    PubMed

    Green, R; Giebisch, G; Unwin, R; Weinstein, A M

    1991-12-01

    Simultaneous microperfusion of proximal tubules and peritubular capillaries in kidneys of rats anesthetized with Inactin was used to examine water reabsorption by this epithelium. Osmolality of the luminal solution was varied with changes in NaCl concentration and by the addition of raffinose. Capillary perfusates contained either low (2 g/dl) or high (16 g/dl) concentrations of albumin. We used low-bicarbonate perfusates for both lumen and capillary so that we might apply the nonequilibrium thermodynamic model of transport for a single solute (NaCl) to interpret our observations. Linear regression with the volume flux equation Jv = -Lp delta II - Lp sigma delta C + Jav (where Jv is volume flux, Lp is hydraulic conductance, delta II is oncotic force, sigma is osmotic reflection coefficient, delta C is salt concentration difference, and Jav is the component of Jv not attributed to transepithelial hydrostatic or osmotic forces) revealed a tubule water permeability (Pf = 0.11 +/- 0.01 cm/s) and a sigma (0.74 +/- 0.08) in agreement with previous determinations. These transport parameters were unaffected by changes in peritubular protein. We also found that Jav was substantial, approximately three-fourths of the rate of isotonic transport under these perfusion conditions. Further, this component of water transport nearly doubled with the transition from low- to high-protein peritubular capillary perfusion. When expressed as a capacity for water reabsorption against an osmotic gradient, the salt concentration differences required to null volume flux were 13.2 +/- 2.4 and 29.4 +/- 4.0 mosmol/kgH2O under low and high peritubular protein. Our data suggest that this protein effect is, most likely, an increase in solute transport by the tubule epithelial cells. PMID:1750518

  16. Genetic control of Aedes mosquitoes.

    PubMed

    Alphey, Luke; McKemey, Andrew; Nimmo, Derric; Neira Oviedo, Marco; Lacroix, Renaud; Matzen, Kelly; Beech, Camilla

    2013-06-01

    Aedes mosquitoes include important vector species such as Aedes aegypti, the major vector of dengue. Genetic control methods are being developed for several of these species, stimulated by an urgent need owing to the poor effectiveness of current methods combined with an increase in chemical pesticide resistance. In this review we discuss the various genetic strategies that have been proposed, their present status, and future prospects. We focus particularly on those methods that are already being tested in the field, including RIDL and Wolbachia-based approaches. PMID:23816508

  17. Genetic control of Aedes mosquitoes

    PubMed Central

    Alphey, Luke; McKemey, Andrew; Nimmo, Derric; Neira Oviedo, Marco; Lacroix, Renaud; Matzen, Kelly; Beech, Camilla

    2013-01-01

    Aedes mosquitoes include important vector species such as Aedes aegypti, the major vector of dengue. Genetic control methods are being developed for several of these species, stimulated by an urgent need owing to the poor effectiveness of current methods combined with an increase in chemical pesticide resistance. In this review we discuss the various genetic strategies that have been proposed, their present status, and future prospects. We focus particularly on those methods that are already being tested in the field, including RIDL and Wolbachia-based approaches. PMID:23816508

  18. Rheogenic transport in the renal proximal tubule

    PubMed Central

    1983-01-01

    The electrophysiology of the renal Na-K ATPase was studied in isolated perfused amphibian proximal tubules during alterations in bath (serosal) potassium. Intracellular and extracellular ionic activity measurements permitted continuous evaluation of the Nernst potentials for Na+, K+, and Cl- across the basolateral membrane. The cell membrane and transepithelial potential differences and resistances were also determined. Return of K to the basal (serosal) solution after a 20-min incubation in K-free solution hyperpolarized the basolateral membrane to an electrical potential that was more negative than the Nernst potential for either Na, Cl, or K. This constitutes strong evidence that at least under stimulated conditions the Na-K ATPase located at the basolateral membrane of the renal proximal tubule mediates a rheogenic process which directly transfers net charge across the cell membrane. Interpretation of these data in terms of an electrical equivalent circuit permitted calculation of both the rheogenic current and the Na/K coupling ratio of the basolateral pump. During the period between 1 and 3 min after pump reactivation by return of bath K, the basolateral rheogenic current was directly proportional to the intracellular Na activity, and the pump stoichiometry transiently exceeded the coupling ratio of 3Na to 2K reported in other preparations. PMID:6319539

  19. Microevolution of Aedes aegypti.

    PubMed

    Louise, Caroline; Vidal, Paloma Oliveira; Suesdek, Lincoln

    2015-01-01

    Scientific research into the epidemiology of dengue frequently focuses on the microevolution and dispersion of the mosquito Aedes aegypti. One of the world's largest urban agglomerations infested by Ae. aegypti is the Brazilian megalopolis of Sao Paulo, where >26,900 cases of dengue were reported until June 2015. Unfortunately, the dynamics of the genetic variability of Ae. aegypti in the Sao Paulo area have not been well studied. To reduce this knowledge gap, we assessed the morphogenetic variability of a population of Ae. aegypti from a densely urbanised neighbourhood of Sao Paulo. We tested if allelic patterns could vary over a short term and if wing shape could be a predictor of the genetic variation. Over a period of 14 months, we examined the variation of genetic (microsatellites loci) and morphological (wing geometry) markers in Ae. aegypti. Polymorphisms were detected, as revealed by the variability of 20 microsatellite loci (115 alleles combined; overall Fst = 0.0358) and 18 wing landmarks (quantitative estimator Qst = 0.4732). These levels of polymorphism are higher than typically expected to an exotic species. Allelic frequencies of the loci changed over time and temporal variation in the wing shape was even more pronounced, permitting high reclassification levels of chronological samples. In spite of the fact that both markers underwent temporal variation, no correlation was detected between their dynamics. We concluded that microevolution was detected despite the short observational period, but the intensities of change of the markers were discrepant. Wing shape failed from predicting allelic temporal variation. Possibly, natural selection (Qst>Fst) or variance of expressivity of wing phenotype are involved in this discrepancy. Other possibly influential factors on microevolution of Ae. aegypti are worth searching. Additionally, the implications of the rapid evolution and high polymorphism of this mosquito vector on the efficacy of control methods have

  20. Microevolution of Aedes aegypti

    PubMed Central

    Louise, Caroline; Vidal, Paloma Oliveira; Suesdek, Lincoln

    2015-01-01

    Scientific research into the epidemiology of dengue frequently focuses on the microevolution and dispersion of the mosquito Aedes aegypti. One of the world’s largest urban agglomerations infested by Ae. aegypti is the Brazilian megalopolis of Sao Paulo, where >26,900 cases of dengue were reported until June 2015. Unfortunately, the dynamics of the genetic variability of Ae. aegypti in the Sao Paulo area have not been well studied. To reduce this knowledge gap, we assessed the morphogenetic variability of a population of Ae. aegypti from a densely urbanised neighbourhood of Sao Paulo. We tested if allelic patterns could vary over a short term and if wing shape could be a predictor of the genetic variation. Over a period of 14 months, we examined the variation of genetic (microsatellites loci) and morphological (wing geometry) markers in Ae. aegypti. Polymorphisms were detected, as revealed by the variability of 20 microsatellite loci (115 alleles combined; overall Fst = 0.0358) and 18 wing landmarks (quantitative estimator Qst = 0.4732). These levels of polymorphism are higher than typically expected to an exotic species. Allelic frequencies of the loci changed over time and temporal variation in the wing shape was even more pronounced, permitting high reclassification levels of chronological samples. In spite of the fact that both markers underwent temporal variation, no correlation was detected between their dynamics. We concluded that microevolution was detected despite the short observational period, but the intensities of change of the markers were discrepant. Wing shape failed from predicting allelic temporal variation. Possibly, natural selection (Qst>Fst) or variance of expressivity of wing phenotype are involved in this discrepancy. Other possibly influential factors on microevolution of Ae. aegypti are worth searching. Additionally, the implications of the rapid evolution and high polymorphism of this mosquito vector on the efficacy of control methods

  1. Differentiated kidney epithelial cells repair injured proximal tubule.

    PubMed

    Kusaba, Tetsuro; Lalli, Matthew; Kramann, Rafael; Kobayashi, Akio; Humphreys, Benjamin D

    2014-01-28

    Whether kidney proximal tubule harbors a scattered population of epithelial stem cells is a major unsolved question. Lineage-tracing studies, histologic characterization, and ex vivo functional analysis results conflict. To address this controversy, we analyzed the lineage and clonal behavior of fully differentiated proximal tubule epithelial cells after injury. A CreER(T2) cassette was knocked into the sodium-dependent inorganic phosphate transporter SLC34a1 locus, which is expressed only in differentiated proximal tubule. Tamoxifen-dependent recombination was absolutely specific to proximal tubule. Clonal analysis after injury and repair showed that the bulk of labeled cells proliferate after injury with increased clone size after severe compared with mild injury. Injury to labeled proximal tubule epithelia induced expression of CD24, CD133, vimentin, and kidney-injury molecule-1, markers of putative epithelial stem cells in the human kidney. Similar results were observed in cultured proximal tubules, in which labeled clones proliferated and expressed dedifferentiation and injury markers. When mice with completely labeled kidneys were subject to injury and repair there was no dilution of fate marker despite substantial proliferation, indicating that unlabeled progenitors do not contribute to kidney repair. During nephrogenesis and early kidney growth, single proximal tubule clones expanded, suggesting that differentiated cells also contribute to tubule elongation. These findings provide no evidence for an intratubular stem-cell population, but rather indicate that terminally differentiated epithelia reexpress apparent stem-cell markers during injury-induced dedifferentiation and repair. PMID:24127583

  2. Shape transitions in anisotropic multicomponent lipid tubules

    NASA Astrophysics Data System (ADS)

    Atherton, Tim

    2016-05-01

    Abstract Ternary mixtures of saturated and unsaturated lipids together with cholesterol can be induced to phase separate by photo-peroxidation into lipid-ordered Lo and lipid-disordered Ld domains. Because these have different mechanical properties, the phase separation is accompanied by dramatic changes in morphology. This work considers a tubule composed of Ld phase with Lo phase inclusions that possess greater rigidity; this system has been shown experimentally by Yuan and coworkers to spontaneously adopt either banded or disc configurations following phase separation. The static behaviour of inter-domain interactions is analyzed in each of these geometries by solving the linearized shape equations. These calculations suggest a possible mechanism by which the two structures form.

  3. Golgi protein FAPP2 tubulates membranes

    PubMed Central

    Cao, Xinwang; Coskun, Ünal; Rössle, Manfred; Buschhorn, Sabine B.; Grzybek, Michal; Dafforn, Timothy R.; Lenoir, Marc; Overduin, Michael; Simons, Kai

    2009-01-01

    The Golgi-associated four-phosphate adaptor protein 2 (FAPP2) has been shown to possess transfer activity for glucosylceramide both in vitro and in cells. We have previously shown that FAPP2 is involved in apical transport from the Golgi complex in epithelial MDCK cells. In this paper we assign an unknown activity for the protein as well as providing structural insight into protein assembly and a low-resolution envelope structure. By applying analytical ultracentrifugation and small-angle x-ray scattering, we show that FAPP2 is a dimeric protein in solution, having a curved shape 30 nm in length. The purified FAPP2 protein has the capability to form tubules from membrane sheets in vitro. This activity is dependent on the phosphoinositide-binding activity of the PH domain of FAPP2. These data suggest that FAPP2 functions directly in the formation of apical carriers in the trans-Golgi network. PMID:19940249

  4. Dentinal tubules revealed with X-ray tensor tomography.

    PubMed

    Jud, Christoph; Schaff, Florian; Zanette, Irene; Wolf, Johannes; Fehringer, Andreas; Pfeiffer, Franz

    2016-09-01

    Dentin is a mineralized material making up most of the tooth bulk. A system of microtubules, so called dentinal tubules, transverses it radially from the pulp chamber to the outside. This highly oriented structure leads to anisotropic mechanical properties directly connected to the tubules orientation and density: the ultimate tensile strength as well as the fracture toughness and the shear strength are largest perpendicular to dentinal tubules. Consequently, the fatigue strength depends on the direction of dentinal tubules, too. However, none of the existing techniques used to investigate teeth provide access to orientation and density of dentinal tubules for an entire specimen in a non-destructive way. In this paper, we measure a third molar human tooth both with conventional micro-CT and X-ray tensor tomography (XTT). While the achievable resolution in micro-CT is too low to directly resolve the dentinal tubules, we provide strong evidence that the direction and density of dentinal tubules can be indirectly measured by XTT, which exploits small-angle X-ray scattering to retrieve a 3D map of scattering tensors. We show that the mean directions of scattering structures correlate to the orientation of dentinal tubules and that the mean effective scattering strength provides an estimation of the relative density of dentinal tubules. Thus, this method could be applied to investigate the connection between tubule orientation and fatigue or tensile properties of teeth for a full sample without cutting one, non-representative peace of tooth out of the full sample. PMID:27424269

  5. Flavivirus susceptibility in Aedes aegypti.

    PubMed

    Black, William C; Bennett, Kristine E; Gorrochótegui-Escalante, Norma; Barillas-Mury, Carolina V; Fernández-Salas, Ildefonso; de Lourdes Muñoz, María; Farfán-Alé, José A; Olson, Ken E; Beaty, Barry J

    2002-01-01

    Aedes aegypti is the primary vector of yellow fever (YF) and dengue fever (DF) flaviviruses worldwide. In this review we focus on past and present research on genetic components and environmental factors in Aedes aegypti that appear to control flavivirus transmission. We review genetic relationships among Ae. aegypti populations throughout the world and discuss how variation in vector competence is correlated with overall genetic differences among populations. We describe current research into how genetic and environmental factors jointly affect distribution of vector competence in natural populations. Based on this information, we propose a population genetic model for vector competence and discuss our recent progress in testing this model. We end with a discussion of approaches being taken to identify the genes that may control flavivirus susceptibility in Ae. aegypti. PMID:12234528

  6. Driving change: kidney proximal tubule CSF-1 polarizes macrophages

    PubMed Central

    Perry, Heather M.; Okusa, Mark D.

    2016-01-01

    Macrophage colony-stimulating factor (CSF-1 or M-CSF) is important for kidney repair after acute kidney injury (AKI). CSF-1 is upregulated in tubule epithelial cells in response to kidney injury stimuli and binds to its sole receptor, CSF1R, in an autocrine and paracrine manner. Wang and colleagues used a genetic approach to constitutively delete Csf1 in proximal tubules to establish that proximal tubule production of CSF-1 is important for polarizing and skewing macrophages toward an M2 phenotype, and for recovery from AKI. PMID:26649657

  7. Globally invasive, withdrawing at home: Aedes albopictus and Aedes japonicus facing the rise of Aedes flavopictus

    NASA Astrophysics Data System (ADS)

    Chaves, Luis Fernando

    2016-04-01

    It has been suggested that climate change may have facilitated the global expansion of invasive disease vectors, since several species have expanded their range as temperatures have warmed. Here, we present results from observations on two major global invasive mosquito vectors (Diptera: Culicidae), Aedes albopictus (Skuse) and Aedes japonicus (Theobald), across the altitudinal range of Mt. Konpira, Nagasaki, Japan, a location within their native range, where Aedes flavopictus Yamada, formerly a rare species, has now become dominant. Spatial abundance patterns of the three species suggest that temperature is an important factor influencing their adult distribution across the altitudinal range of Mt. Konpira. Temporal abundance patterns, by contrast, were associated with rainfall and showed signals of density-dependent regulation in the three species. The spatial and temporal analysis of abundance patterns showed that Ae. flavopictus and Ae. albopictus were negatively associated, even when accounting for differential impacts of weather and other environmental factors in their co-occurrence patterns. Our results highlight a contingency in the expansion of invasive vectors, the potential emergence of changes in their interactions with species in their native communities, and raise the question of whether these changes might be useful to predict the emergence of future invasive vectors.

  8. Heterogeneity of T-Tubules in Pig Hearts

    PubMed Central

    Gadeberg, Hanne C.; Bond, Richard C.; Kong, Cherrie H. T.; Chanoit, Guillaume P.; Ascione, Raimondo; Cannell, Mark B.; James, Andrew F.

    2016-01-01

    Background T-tubules are invaginations of the sarcolemma that play a key role in excitation-contraction coupling in mammalian cardiac myocytes. Although t-tubules were generally considered to be effectively absent in atrial myocytes, recent studies on atrial cells from larger mammals suggest that t-tubules may be more numerous than previously supposed. However, the degree of heterogeneity between cardiomyocytes in the extent of the t-tubule network remains unclear. The aim of the present study was to investigate the t-tubule network of pig atrial myocytes in comparison with ventricular tissue. Methods Cardiac tissue was obtained from young female Landrace White pigs (45–75 kg, 5–6 months old). Cardiomyocytes were isolated by arterial perfusion with a collagenase-containing solution. Ca2+ transients were examined in field-stimulated isolated cells loaded with fluo-4-AM. Membranes of isolated cells were visualized using di-8-ANEPPS. T-tubules were visualized in fixed-frozen tissue sections stained with Alexa-Fluor 488-conjugated WGA. Binary images were obtained by application of a threshold and t-tubule density (TTD) calculated. A distance mapping approach was used to calculate half-distance to nearest t-tubule (HDTT). Results & Conclusion The spatio-temporal properties of the Ca2+ transient appeared to be consistent with the absence of functional t-tubules in isolated atrial myocytes. However, t-tubules could be identified in a sub-population of atrial cells in frozen sections. While all ventricular myocytes had TTD >3% (mean TTD = 6.94±0.395%, n = 24), this was true of just 5/22 atrial cells. Mean atrial TTD (2.35±0.457%, n = 22) was lower than ventricular TTD (P<0.0001). TTD correlated with cell-width (r = 0.7756, n = 46, P<0.0001). HDTT was significantly greater in the atrial cells with TTD ≤3% (2.29±0.16 μm, n = 17) than in either ventricular cells (1.33±0.05 μm, n = 24, P<0.0001) or in atrial cells with TTD >3% (1.65±0.06 μm, n = 5, P<0.05). These

  9. Cooperation of phosphoinositides and BAR domain proteins in endosomal tubulation.

    PubMed

    Shinozaki-Narikawa, Naeko; Kodama, Tatsuhiko; Shibasaki, Yoshikazu

    2006-11-01

    Phosphorylated derivatives of phosphatidylinositol (PtdIns) regulate many intracellular events, including vesicular trafficking and actin remodeling, by recruiting proteins to their sites of function. PtdIns(4,5)-bisphosphate [PI(4,5)P2] and related phosphoinositides are mainly synthesized by type I PtdIns-4-phosphate 5-kinases (PIP5Ks). We found that PIP5K induces endosomal tubules in COS-7 cells. ADP-ribosylation factor (ARF) 6 has been shown to act upstream of PIP5K and regulate endocytic transport and tubulation. ARF GAP with coiled-coil, ankyrin repeat, and pleckstrin homology domains 1 (ACAP1) has guanosine triphosphatase-activating protein (GAP) activity for ARF6. While there were few tubules induced by the expression of ACAP1 alone, numerous endosomal tubules were induced by coexpression of PIP5K and ACAP1. ACAP1 has a pleckstrin homology (PH) domain known to bind phosphoinositide and a Bin/amphiphysin/Rvs (BAR) domain that has been reported to detect membrane curvature. Truncated and point mutations in the ACAP1 BAR and PH domains revealed that both BAR and PH domains are required for tubulation. These results suggest that two ARF6 downstream molecules, PIP5K and ACAP1, function together in endosomal tubulation and that phosphoinositide levels may regulate endosomal dynamics. PMID:17010122

  10. Immunodissection and culture of rabbit cortical collecting tubule cells

    SciTech Connect

    Spielman, W.S.; Sonnenburg, W.K.; Allen, M.L.; Arend, L.J.; Gerozissis, K.; Smith, W.L.

    1986-08-01

    A mouse monoclonal antibody designated IgG3 (rct-30) has been prepared that reacts specifically with an antigen on the surface of all cells comprising the cortical and medullary rabbit renal collecting tubule including the arcades. Plastic culture dishes coated with IgG3 (rct-30) were used to isolate collecting tubule cells from collagenase dispersions of rabbit renal cortical cells by immunoadsorption. Typically, 10W rabbit cortical collecting tubule (RCCT) cells were obtained from 5 g of renal cortex (2 kidneys). Between 20 and 30% of the RCCT cells were reactive with peanut lectin suggesting that RCCT cells are a mixture of principal and intercalated cells. Approximately 10X RCCT cells were obtained after 4 to 5 days in primary culture. Moreover, RCCT cells continued to proliferate after passaging with a doubling time of approx.32 h. RCCT cells passaged once and then cultured 4-5 days were found 1) to synthesize cAMP in response to arginine vasopressin (AVP), prostaglandin E2 (PGE2), isoproterenol, and parathyroid hormone, but not calcitonin, prostaglandin D2, or prostaglandin I, and 2) to release PGE2 in response to bradykinin but not arginine vasopressin or isoproterenol. The results indicate that cultured RCCT cells retain many of the hormonal, histochemical, and morphological properties expected for a mixture of principal and intercalated rabbit cortical collecting tubule epithelia. RCCT cells should prove useful both for studying hormonal interactions in the cortical collecting tubule and as a starting population for isolating intercalated collecting tubule epithelia.

  11. Human proximal tubule cells form functional microtissues.

    PubMed

    Prange, Jenny A; Bieri, Manuela; Segerer, Stephan; Burger, Charlotte; Kaech, Andres; Moritz, Wolfgang; Devuyst, Olivier

    2016-04-01

    The epithelial cells lining the proximal tubules of the kidney mediate complex transport processes and are particularly vulnerable to drug toxicity. Drug toxicity studies are classically based on two-dimensional cultures of immortalized proximal tubular cells. Such immortalized cells are dedifferentiated, and lose transport properties (including saturable endocytic uptake) encountered in vivo. Generating differentiated, organotypic human microtissues would potentially alleviate these limitations and facilitate drug toxicity studies. Here, we describe the generation and characterization of kidney microtissues from immortalized (HK-2) and primary (HRPTEpiC) human renal proximal tubular epithelial cells under well-defined conditions. Microtissue cultures were done in hanging drop GravityPLUS™ culture plates and were characterized for morphology, proliferation and differentiation markers, and by monitoring the endocytic uptake of albumin. Kidney microtissues were successfully obtained by co-culturing HK-2 or HRPTEpiC cells with fibroblasts. The HK-2 microtissues formed highly proliferative, but dedifferentiated microtissues within 10 days of culture, while co-culture with fibroblasts yielded spherical structures already after 2 days. Low passage HRPTEpiC microtissues (mono- and co-culture) were less proliferative and expressed tissue-specific differentiation markers. Electron microscopy evidenced epithelial differentiation markers including microvilli, tight junctions, endosomes, and lysosomes in the co-cultured HRPTEpiC microtissues. The co-cultured HRPTEpiC microtissues showed specific uptake of albumin that could be inhibited by cadmium and gentamycin. In conclusion, we established a reliable hanging drop protocol to obtain functional kidney microtissues with proximal tubular epithelial cell lines. These microtissues could be used for high-throughput drug and toxicology screenings, with endocytosis as a functional readout. PMID:26676951

  12. From single molecule to single tubules

    NASA Astrophysics Data System (ADS)

    Guo, Chin-Lin

    2012-02-01

    Biological systems often make decisions upon conformational changes and assembly of single molecules. In vivo, epithelial cells (such as the mammary gland cells) can respond to extracellular matrix (ECM) molecules, type I collagen (COL), and switch their morphology from a lobular lumen (100-200 micron) to a tubular lumen (1mm-1cm). However, how cells make such a morphogenetic decision through interactions with each other and with COL is unclear. Using a temporal control of cell-ECM interaction, we find that epithelial cells, in response to a fine-tuned percentage of type I collagen (COL) in ECM, develop various linear patterns. Remarkably, these patterns allow cells to self-assemble into a tubule of length ˜ 1cm and diameter ˜ 400 micron in the liquid phase (i.e., scaffold-free conditions). In contrast with conventional thought, the linear patterns arise through bi-directional transmission of traction force, but not through diffusible biochemical factors secreted by cells. In turn, the transmission of force evokes a long-range (˜ 600 micron) intercellular mechanical interaction. A feedback effect is encountered when the mechanical interaction modifies cell positioning and COL alignment. Micro-patterning experiments further reveal that such a feedback is a novel cell-number-dependent, rich-get-richer process, which allows cells to integrate mechanical interactions into long-range (> 1mm) linear coordination. Our results suggest a mechanism cells can use to form and coordinate long-range tubular patterns, independent of those controlled by diffusible biochemical factors, and provide a new strategy to engineer/regenerate epithelial organs using scaffold-free self-assembly methods.

  13. Luminal Na+/H+ exchange in the proximal tubule

    PubMed Central

    Bobulescu, I. Alexandru

    2010-01-01

    The proximal tubule is critical for whole-organism volume and acid–base homeostasis by reabsorbing filtered water, NaCl, bicarbonate, and citrate, as well as by excreting acid in the form of hydrogen and ammonium ions and producing new bicarbonate in the process. Filtered organic solutes such as amino acids, oligopeptides, and proteins are also retrieved by the proximal tubule. Luminal membrane Na+/H+ exchangers either directly mediate or indirectly contribute to each of these processes. Na+/H+ exchangers are a family of secondary active transporters with diverse tissue and subcellular distributions. Two isoforms, NHE3 and NHE8, are expressed at the luminal membrane of the proximal tubule. NHE3 is the prevalent isoform in adults, is the most extensively studied, and is tightly regulated by a large number of agonists and physiological conditions acting via partially defined molecular mechanisms. Comparatively little is known about NHE8, which is highly expressed at the lumen of the neonatal proximal tubule and is mostly intracellular in adults. This article discusses the physiology of proximal Na+/H+ exchange, the multiple mechanisms of NHE3 regulation, and the reciprocal relationship between NHE3 and NHE8 at the lumen of the proximal tubule. PMID:18853182

  14. Degradation and transport of AVP by proximal tubule

    SciTech Connect

    Carone, F.A.; Christensen, E.I.; Flouret, G. Univ. of Aarhus )

    1987-12-01

    High-performance liquid chromatography (HPLC) analysis revealed that (3,4,5-{sup 3}H-Phe{sup 3},Arg{sup 8})vasopressin (({sup 3}H)AVP) was not degraded by isolated renal brush-border membranes or by a cortical lysosomal fraction in vitro; however, in the presence of 1 mM reduced glutathione, ({sup 3}H)AVP was degraded by both preparations. Renal cortical homogenates in vitro and luminal peptidases of proximal tubule in vivo degraded ({sup 3}H)AVP and in both instances yielded phenylalanine, hexapeptide AVP 1-6, heptapeptide AVP 1-7, octapeptide AVP 1-8, and two uncharacterized products X and Y. These data suggest that filtered AVP is reduced in the proximal tubule by a reduced glutathione-dependent transhydrogenase and subsequently cleaved to ({sup 3}H)Phe by tubular aminopeptidases. Following microinfusion of ({sup 3}H)AVP into proximal tubules, 15.7% of the label was absorbed. Five and fifteen minutes after infusion of ({sup 3}H)AVP, sequestration of total label in proximal tubules was 4.5 and 2.1%, respectively, and quantitative electron microscope autoradiography revealed accumulation of grains over apical endocytic vacuoles and lysosomes consistent with endocytic uptake and rapid lysosomal degradation of AVP and/or a large metabolite. Thus, enzymatic cleavage of AVP by luminal and lysosomal peptidases in proximal tubules could involve disulfide bond, C-terminal, and N-terminal loci.

  15. Promising new tools to fight Aedes mosquitoes.

    PubMed

    2016-08-01

    Two new tools for suppressing Aedes aegypti mosquito populations have been recommended for pilot testing. Carefully designed trials will be needed to see whether they actually reduce disease as well. Andréia Azevedo Soares reports. PMID:27516632

  16. Aedes mosquito species in western Saudi Arabia.

    PubMed

    Alikhan, Masroor; Al Ghamdi, Khalid; Mahyoub, Jazem Abdullah

    2014-01-01

    The Aedes Meigen (Diptera: Culicidae) mosquito species populations in the western region of Saudi Arabia, especially in and around Jeddah, are increasing, therefore increasing susceptibility of humans to the dengue virus. An extensive survey was carried out for one year, and four species were identified with the help of different pictorial keys available. The identification was based on morphological characteristics of adult female Aedes mosquitoes. PMID:25373216

  17. Dispersal of Engineered Male Aedes aegypti Mosquitoes

    PubMed Central

    Capurro, Margareth L.; Alphey, Luke; Donnelly, Christl A.; McKemey, Andrew R.

    2015-01-01

    Background Aedes aegypti, the principal vector of dengue fever, have been genetically engineered for use in a sterile insect control programme. To improve our understanding of the dispersal ecology of mosquitoes and to inform appropriate release strategies of ‘genetically sterile’ male Aedes aegypti detailed knowledge of the dispersal ability of the released insects is needed. Methodology/Principal Findings The dispersal ability of released ‘genetically sterile’ male Aedes aegypti at a field site in Brazil has been estimated. Dispersal kernels embedded within a generalized linear model framework were used to analyse data collected from three large scale mark release recapture studies. The methodology has been applied to previously published dispersal data to compare the dispersal ability of ‘genetically sterile’ male Aedes aegypti in contrasting environments. We parameterised dispersal kernels and estimated the mean distance travelled for insects in Brazil: 52.8m (95% CI: 49.9m, 56.8m) and Malaysia: 58.0m (95% CI: 51.1m, 71.0m). Conclusions/Significance Our results provide specific, detailed estimates of the dispersal characteristics of released ‘genetically sterile’ male Aedes aegypti in the field. The comparative analysis indicates that despite differing environments and recapture rates, key features of the insects’ dispersal kernels are conserved across the two studies. The results can be used to inform both risk assessments and release programmes using ‘genetically sterile’ male Aedes aegypti. PMID:26554922

  18. Accelerated reabsorption in the proximal tubule produced by volume depletion

    PubMed Central

    Weiner, Michael W.; Weinman, Edward J.; Kashgarian, Michael; Hayslett, John P.

    1971-01-01

    The renal response to chronic depletion of extracellular volume was examined using the techniques of micropuncture. Depletion of salt and water was produced by administration of furosemide to rats maintained on a sodium-free diet. There was a marked fall in body weight, plasma volume, and glomerular filtration rate. The intrinsic reabsorptive capacity of the proximal tubule, measured by the split-droplet technique, was greatly enhanced. The acceleration of proximal fluid reabsorption could not be accounted for by changes in filtration rate, tubular geometry, or aldosterone secretion. The half-time of droplet reabsorption in the distal tubule was not altered by sodium depletion. An increase in the reabsorption of fluid in the proximal tubule, as demonstrated directly in the present experiments, provides an explanation for a variety of clinical phenomena associated with volume depletion. Images PMID:5090054

  19. Polyunsaturated Fatty Acids in Lipid Bilayers and Tubules

    NASA Astrophysics Data System (ADS)

    Hirst, Linda S.; Yuan, Jing; Pramudya, Yohannes; Nguyen, Lam T.

    2007-03-01

    Omega-3 polyunsaturated fatty acids (PUFAs) are found in a variety of biological membranes and have been implicated with lipid raft formation and possible function, typical molecules include DHA (Docosahexanoic Acid) and AA (Alphalinoleic Acid) which have been the focus of considerable attention in recent years. We are interested in the phase behavior of these molecules in the lipid bilayer. The addition of lipid molecules with polyunsaturated chains has a clear effect on the fluidity and curvature of the membrane and we investigate the effects the addition of polyunsaturated lipids on bilayer structure and tubule formation. Self-assembled cylindrical lipid tubules have attracted considerable attention because of their interesting structures and potential technological applications. Using x-ray diffraction techniques, Atomic Force Microscopy and confocal fluorescence imaging, both symmetric and mixed chain lipids were incorporated into model membranes and the effects on bilayer structure and tubule formation investigated.

  20. Apical potassium channels in the rat connecting tubule.

    PubMed

    Frindt, Gustavo; Palmer, Lawrence G

    2004-11-01

    Apical membrane K channels in the rat connecting tubule (CNT) were studied using the patch-clamp technique. Tubules were isolated from the cortical labyrinth of the kidney and split open to provide access to the apical membrane. Cell-attached patches were formed on presumed principal and/or connecting tubule cells. The major channel type observed had a single-channel conductance of 52 pS, high open probability and kinetics that were only weakly dependent on voltage. These correspond closely to the "SK"-type channels in the cortical collecting duct, identified with the ROMK (Kir1.1) gene product. A second channel type, which was less frequently observed, mediated larger currents and was strongly activated by depolarization of the apical membrane voltage. These were identified as BK or maxi-K channels. The density of active SK channels revealed a high degree of clustering. Although heterogeneity of tubules or of cell types within a tubule could not be excluded, the major factor underlying the distribution appeared to be the presence of channel clusters on the membrane of individual cells. The overall density of channels was higher than that previously found in the cortical collecting tubule (CCT). In contrast to results in the CCT, we did not detect an increase in the overall density of SK channels in the apical membrane after feeding the animals a high-K diet. However, the activity of amiloride-sensitive Na channels was undetectable under control conditions but was increased after both 1 day (90 +/- 24 pA/cell) or 7 days (385 +/- 82 pA/cell) of K loading. Thus one important factor leading to an increased K secretion in the CNT in response to increased dietary K is an increased apical Na conductance, leading to depolarization of the apical membrane voltage and an increased driving force for K movement out into the tubular lumen. PMID:15280155

  1. Rhamnolipids: solution against Aedes aegypti?

    PubMed Central

    Silva, Vinicius L.; Lovaglio, Roberta B.; Von Zuben, Claudio J.; Contiero, Jonas

    2015-01-01

    Aedes aegypti mosquitoes are the primary transmitters of dengue fever, urban yellow fever, and chikungunya viruses. This mosquito has developed resistance to the insecticides currently used to control their populations. These chemical insecticides are harmful to the environment and can have negative effects on human health. Rhamnolipids are environmentally compatible biological surfactants, but their insecticidal activity has not been extensively studied. The present study evaluated the potential larvicidal, insecticidal, and repellent activities of rhamnolipids against A. aegypti. At concentrations of 800, 900, and 1000 mg/L, rhamnolipids eliminated all mosquito larvae in 18 h and killed 100% of adults at 1000 mg/L. According to the results it may be conclude that rhamnolipids should be applied to control larvae and mosquitos besides present the repellency activity against A. aegypti. PMID:25762986

  2. Innervation of the renal proximal convoluted tubule of the rat

    SciTech Connect

    Barajas, L.; Powers, K. )

    1989-12-01

    Experimental data suggest the proximal tubule as a major site of neurogenic influence on tubular function. The functional and anatomical axial heterogeneity of the proximal tubule prompted this study of the distribution of innervation sites along the early, mid, and late proximal convoluted tubule (PCT) of the rat. Serial section autoradiograms, with tritiated norepinephrine serving as a marker for monoaminergic nerves, were used in this study. Freehand clay models and graphic reconstructions of proximal tubules permitted a rough estimation of the location of the innervation sites along the PCT. In the subcapsular nephrons, the early PCT (first third) was devoid of innervation sites with most of the innervation occurring in the mid (middle third) and in the late (last third) PCT. Innervation sites were found in the early PCT in nephrons located deeper in the cortex. In juxtamedullary nephrons, innervation sites could be observed on the PCT as it left the glomerulus. This gradient of PCT innervation can be explained by the different tubulovascular relationships of nephrons at different levels of the cortex. The absence of innervation sites in the early PCT of subcapsular nephrons suggests that any influence of the renal nerves on the early PCT might be due to an effect of neurotransmitter released from renal nerves reaching the early PCT via the interstitium and/or capillaries.

  3. TRANSCRIPT PROFILING IN TURKEY SPERM STORAGE TUBULES USING SAGE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sperm storage tubules (SST) are unique epithelial structures within the avian oviduct that provide for prolonged storage of fertile sperm following natural mating or artificial insemination (AI). In turkeys, spermatozoa can remain fertile after being stored in the SST for upwards of 70 days. We...

  4. Dynamic tubulation of mitochondria drives mitochondrial network formation

    PubMed Central

    Wang, Chong; Du, Wanqing; Su, Qian Peter; Zhu, Mingli; Feng, Peiyuan; Li, Ying; Zhou, Yichen; Mi, Na; Zhu, Yueyao; Jiang, Dong; Zhang, Senyan; Zhang, Zerui; Sun, Yujie; Yu, Li

    2015-01-01

    Mitochondria form networks. Formation of mitochondrial networks is important for maintaining mitochondrial DNA integrity and interchanging mitochondrial material, whereas disruption of the mitochondrial network affects mitochondrial functions. According to the current view, mitochondrial networks are formed by fusion of individual mitochondria. Here, we report a new mechanism for formation of mitochondrial networks through KIF5B-mediated dynamic tubulation of mitochondria. We found that KIF5B pulls thin, highly dynamic tubules out of mitochondria. Fusion of these dynamic tubules, which is mediated by mitofusins, gives rise to the mitochondrial network. We further demonstrated that dynamic tubulation and fusion is sufficient for mitochondrial network formation, by reconstituting mitochondrial networks in vitro using purified fusion-competent mitochondria, recombinant KIF5B, and polymerized microtubules. Interestingly, KIF5B only controls network formation in the peripheral zone of the cell, indicating that the mitochondrial network is divided into subzones, which may be constructed by different mechanisms. Our data not only uncover an essential mechanism for mitochondrial network formation, but also reveal that different parts of the mitochondrial network are formed by different mechanisms. PMID:26206315

  5. High yield synthesis and HREM study of fullerene tubules and fullerene onions

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoping; Wang, Youwen; Li, Wenzhou

    1994-01-01

    The fullerene tubules and fullerene onions are synthesized in macroscopic quantity with high yield by modified Kratschmer et. al. method. Besides ordinary concentric fullerene tubules, also are observed abnormal nonconcentric multilayer glaphitic tubules with varying layer spacings. The curved graphitic tubules are observed, showing the tendency to form torus. Under appropriate helium pressure, about half of the synthesized product is the multi-shell fullerene onions, polyhedral in shape in accord with the theoretical calculation. [11

  6. On the analysis of parasite effect for Aedes aegypti and Aedes albopictus population

    NASA Astrophysics Data System (ADS)

    Kallista, Meta; Aldila, Dipo; Nuraini, Nuning; Soewono, Edy

    2014-03-01

    It has been reported in some countries that the population of Aedes aegypti has been significantly reduced by the invasion of Aedes albopictus. There has been a hypothesis explaining this phenomenon of which investigated the influence of parasites pathogenesis to the competition between these two mosquito species in the fields. Ascogregarina taiwanensis and Ascogregarina culicis are known as parasites that infect Aedes albopictus and Aedes aegypti, respectively. Several studies have concluded that Ascogregarina taiwanensis caused high fatality for Aedes aegypti larvae, but Ascogregarina culicis was not pathogenic to Aedes albopictus larvae. Therefore, Ascogregarina taiwanensis may contribute to reduce the number of populations Aedes aegypti in the fields. Inspired by these facts, a mathematical model depicting interaction between parasites and mosquitoes is constructed in this paper. In this model are included six dynamic mosquito compartments, i.e. egg, larvae, infected larvae, adult, infected adult and one dynamic compartment for parasite. Derivation of the existence criteria and the stability analysis of parasite-free equilibrium as well as the basic offspring for the model are presented. Numerical simulations for sensitivity analysis indicating the invasive species for variation parameters are shown.

  7. Nepenthes ampullaria (Nepenthaceae) Pitchers Are Unattractive to Gravid Aedes aegypti and Aedes albopictus (Diptera: Culicidae).

    PubMed

    Chou, Lee Yiung; Dykes, Gary A; Wilson, Robyn F; Clarke, Charles M

    2016-02-01

    Nepenthes pitcher plants are colonized by a variety of specialized arthropods. As Aedes mosquitoes are container breeders, Nepenthes pitchers are a potential candidate oviposition site for vector species, such as Aedes aegypti (L.) and Aedes albopictus (Skuse). However, Aedes spp. are not commonly encountered in Nepenthes pitchers, and the environment inside the pitchers of some species is lethal to them. One exception is Nepenthes ampullaria Jack, whose pitchers are known to be colonized by Ae. albopictus on very rare occasions. Given that Ae. albopictus larvae can survive in N. ampullaria pitcher fluids, we sought to determine why pitcher colonization is rare, testing the hypothesis that gravid Aedes mosquitoes are deterred from ovipositing into container habitats that have similar characteristics to N. ampullaria pitchers. Using plastic ovitraps of different sizes, colors, and with different types of fluids (based on the characteristics of N. ampullaria pitchers), we compared oviposition rates by Aedes mosquitoes in urban and rural areas within the geographical range of N. ampullaria near Kuala Lumpur, Malaysia. Ovitraps that were black and large (>250-ml capacity) accumulated significantly more eggs than ovitraps that were smaller, or green in color. In terms of size and color, small, green ovitraps are analogous to N. ampullaria pitchers, indicating that these pitchers are not particularly attractive to gravid Ae. albopictus. Although Aedes spp. are capable of colonizing N. ampullaria pitchers, the pitchers are relatively unattractive to gravid females and do not represent a significant habitat for larvae of dengue vectors at present. PMID:26518035

  8. Rapid identification of Aedes albopictus, Aedes scutellaris, and Aedes aegypti life stages using real-time polymerase chain reaction assays.

    PubMed

    Hill, Lydia A; Davis, Joseph B; Hapgood, George; Whelan, Peter I; Smith, Greg A; Ritchie, Scott A; Cooper, R D; van den Hurk, Andrew F

    2008-12-01

    In 2005, a widespread infestation of Aedes albopictus was discovered in the Torres Strait, the region between northern Australia and New Guinea. To contain this species, an eradication program was implemented in 2006. However, the progress of this program is impeded by the difficulty of morphologically separating Ae. albopictus larvae from the endemic species Aedes scutellaris. In this study, three real-time TaqMan polymerase chain reaction assays that target the ribosomal internal transcribed spacer 1 region were developed to rapidly identify Aedes aegypti, Ae. albopictus, and Ae. scutellaris from northern Australia. Individual eggs, larvae, pupae, and adults, as well as the species composition of mixed pools were accurately identified. The assay method was validated using 703 field-collected specimens from the Torres Strait. PMID:19052295

  9. DIGESTIVE TUBULE ATROPHY IN EASTERN OYSTERS, CRASSOSTREA VIRGINICA (GMELI, 1791), EXPOSED TO SALINITY AND STARVATION STRESS

    EPA Science Inventory

    Oysters sampled in February 1992, from a low salinity site (3 ppt) in Apalachicola Bay, Florida, showed digestive tubule atrophy when salinity site (18 ppt) 16 kilometers away. xperiments designed to induce tubule atrophy in the and two salinity stress tests. o quantify tubule co...

  10. Thiosemicarbazones as Aedes aegypti larvicidal.

    PubMed

    da Silva, João Bosco P; Navarro, Daniela Maria do A F; da Silva, Aluizio G; Santos, Geanne K N; Dutra, Kamilla A; Moreira, Diogo Rodrigo; Ramos, Mozart N; Espíndola, José Wanderlan P; de Oliveira, Ana Daura T; Brondani, Dalci José; Leite, Ana Cristina L; Hernandes, Marcelo Zaldini; Pereira, Valéria R A; da Rocha, Lucas F; de Castro, Maria Carolina A B; de Oliveira, Beatriz C; Lan, Que; Merz, Kenneth M

    2015-07-15

    A set of aryl- and phenoxymethyl-(thio)semicarbazones were synthetized, characterized and biologically evaluated against the larvae of Aedes aegypti (A. aegypti), the vector responsible for diseases like Dengue and Yellow Fever. (Q)SAR studies were useful for predicting the activities of the compounds not included to create the QSAR model as well as to predict the features of a new compound with improved activity. Docking studies corroborated experimental evidence of AeSCP-2 as a potential target able to explain the larvicidal properties of its compounds. The trend observed between the in silico Docking scores and the in vitro pLC50 (equals -log LC50, at molar concentration) data indicated that the highest larvicidal compounds, or the compounds with the highest values for pLC50, are usually those with the higher docking scores (i.e., greater in silico affinity for the AeSCP-2 target). Determination of cytotoxicity for these compounds in mammal cells demonstrated that the top larvicide compounds are non-toxic. PMID:26087027

  11. Bdelloid rotifer, Philodina species in the breeding containers of Aedes aegypti and Aedes albopictus.

    PubMed

    Muniaraj, M; Arunachalam, N; Paramasivan, R; Mariappan, T; Philip Samuel, P; Rajamannar, V

    2012-12-01

    The vector mosquitoes of dengue and chikungunya fever, Aedes aegypti and Aedes albopictus have adapted to feed on humans and undergo larval and pupal development in natural and artificial freshwater collections. Although several studies reported, still, much information is required to understand the successful survival of Aedes mosquitoes in small temporary containers. In an investigation conducted in the chikungunya affected areas of Kerala state, India, the presence of Bdelloid rotifer, Philodina in 95% of breeding habitats of Ae. aegypti and Ae. albopictus was recorded. The role of Philodina in the breeding containers was investigated. It was found that while in control the number of Philodina was found increasing in the water sample during the study period of seven days, the number found decreased in the containers with larvae of Aedes. The gut content analysis also confirmed the presence of the rotating wheel, corona of Philodina in some of the specimen suggests its role as major larval food. PMID:23202612

  12. Tip cells act as dynamic cellular anchors in the morphogenesis of looped renal tubules in Drosophila.

    PubMed

    Weavers, Helen; Skaer, Helen

    2013-11-11

    Tissue morphogenesis involves both the sculpting of tissue shape and the positioning of tissues relative to one another in the body. Using the renal tubules of Drosophila, we show that a specific distal tubule cell regulates both tissue architecture and position in the body cavity. Focusing on the anterior tubules, we demonstrate that tip cells make transient contacts with alary muscles at abdominal segment boundaries, moving progressively forward as convergent extension movements lengthen the tubule. Tip cell anchorage antagonizes forward-directed, TGF-β-guided tubule elongation, thereby ensuring the looped morphology characteristic of renal tubules from worms to humans. Distinctive tip cell exploratory behavior, adhesion, and basement membrane clearing underlie target recognition and dynamic interactions. Defects in these features obliterate tip cell anchorage, producing misshapen and misplaced tubules with impaired physiological function. PMID:24229645

  13. WPH-6112A thermal expansion test of PRESS tubulation

    SciTech Connect

    Kautz, D.D.; Sites, R.L.; Cobb, W.R.

    1994-05-26

    We recently performed the WPH-6112A thermal expansion test of the lower portion of the PRESS program tubulation. The objective of the test was to determine whether the tubulation welds could withstand typical stresses from a 1200 C thermal cycle. Test components failed in two areas: (1) the friction welded Monel to Vanadium tube fitting at the dissimilar metal interface and fell against the outer vanadium tube wall causing it to fail and (2) the thin-walled, outer stainless steel tubing failed by cracking at the weld. Both failures were due to irregular occurences for this system. We feel that the strength of all weldments is adequate to withstand the normal thermal stresses from a 1200 C cycle without failing prematurely.

  14. WPH-6112A thermal expansion test of PRESS tubulation

    NASA Astrophysics Data System (ADS)

    Kautz, D. D.; Sites, R. L.; Cobb, W. R.

    1994-05-01

    We recently performed the WPH-6112A thermal expansion test of the lower portion of the PRESS program tubulation. The objective of the test was to determine whether the tubulation welds could withstand typical stresses from a 1200 C thermal cycle. Test components failed in two areas: (1) the friction welded Monel to Vanadium tube fitting at the dissimilar metal interface and fell against the outer vanadium tube wall causing it to fail, and (2) the thin-walled, outer stainless steel tubing failed by cracking at the weld. Both failures were due to irregular occurrences for this system. We feel that the strength of all weldments is adequate to withstand the normal thermal stresses from a 1200 C cycle without failing prematurely.

  15. Prevalence of Aedes aegypti Linnaeus and Aedes albopictus Skuse in Koderma, Jharkhand.

    PubMed

    Singh, R K; Dhiman, R C; Dua, V K

    2011-09-01

    Entomological survey was carried out in different localities of Koderma district of Jharkhand with a view to study the prevalence, distribution and stratification of areas for Aedes mosquito species. A total of 233 houses were covered during house to house larval and adult survey. Aedes breeding could be detected in 157 houses. In all, a total of 942 domestic water containers were searched, out of which 461 were found positive. The overall house index(HI) container index(CI) breteau index(B1) and pupal index(PI) were 67.38%, 48.94%, 197.85% and 79.4%, respectively. The survey revealed that Aedes aegypti Linnaeus and Aedes albopictus Skuse are well established in Koderma with most of the areas showing high adult and larval indices. The preventive strategy needs to be directed towards minimizing the breeding potential of Aedes and water management practice by individuals along with implementation of urban bye-laws as well as IEC activities to contain Aedes breeding in future. PMID:23781636

  16. Mesoscale Nanoparticles Selectively Target the Renal Proximal Tubule Epithelium

    PubMed Central

    Williams, Ryan M.; Shah, Janki; Ng, Brandon D.; Minton, Denise R.; Gudas, Lorraine J.; Park, Christopher Y.; Heller, Daniel A.

    2015-01-01

    We synthesized “mesoscale” nanoparticles, approximately 400 nm in diameter, which unexpectedly localized selectively in renal proximal tubules and up to 7 times more efficiently in the kidney than other organs. Although nanoparticles typically localize in the liver and spleen, modulating their size and opsonization potential allowed for stable targeting of the kidneys through a new proposed uptake mechanism. Applying this kidney targeting strategy, we anticipate use in the treatment of renal disease and the study of renal physiology. PMID:25811353

  17. Dysferlin and Myoferlin Regulate Transverse Tubule Formation and Glycerol Sensitivity

    PubMed Central

    Demonbreun, Alexis R.; Rossi, Ann E.; Alvarez, Manuel G.; Swanson, Kaitlin E.; Deveaux, H. Kieran; Earley, Judy U.; Hadhazy, Michele; Vohra, Ravneet; Walter, Glenn A.; Pytel, Peter; McNally, Elizabeth M.

    2015-01-01

    Dysferlin is a membrane-associated protein implicated in muscular dystrophy and vesicle movement and function in muscles. The precise role of dysferlin has been debated, partly because of the mild phenotype in dysferlin-null mice (Dysf). We bred Dysf mice to mice lacking myoferlin (MKO) to generate mice lacking both myoferlin and dysferlin (FER). FER animals displayed progressive muscle damage with myofiber necrosis, internalized nuclei, and, at older ages, chronic remodeling and increasing creatine kinase levels. These changes were most prominent in proximal limb and trunk muscles and were more severe than in Dysf mice. Consistently, FER animals had reduced ad libitum activity. Ultrastructural studies uncovered progressive dilation of the sarcoplasmic reticulum and ectopic and misaligned transverse tubules in FER skeletal muscle. FER muscle, and Dysf- and MKO-null muscle, exuded lipid, and serum glycerol levels were elevated in FER and Dysf mice. Glycerol injection into muscle is known to induce myopathy, and glycerol exposure promotes detachment of transverse tubules from the sarcoplasmic reticulum. Dysf, MKO, and FER muscles were highly susceptible to glycerol exposure in vitro, demonstrating a dysfunctional sarcotubule system, and in vivo glycerol exposure induced severe muscular dystrophy, especially in FER muscle. Together, these findings demonstrate the importance of dysferlin and myoferlin for transverse tubule function and in the genesis of muscular dystrophy. PMID:24177035

  18. Mechanosensory function of microvilli of the kidney proximal tubule

    PubMed Central

    Du, Zhaopeng; Duan, Yi; Yan, QingShang; Weinstein, Alan M.; Weinbaum, Sheldon; Wang, Tong

    2004-01-01

    Normal variations in glomerular filtration induce proportional changes in proximal tubule Na+ reabsorption. This “glomerulotubular balance” derives from flow dependence of Na+ uptake across luminal cell membranes; however, the underlying physical mechanism is unknown. Our hypothesis is that flow-dependent reabsorption is an autoregulatory mechanism that is independent of neural and hormonal systems. It is signaled by the hydrodynamic torque (bending moment) on epithelial microvilli. Such signals need to be transmitted to the terminal web to modulate Na+-H+-exchange activity. To investigate this hypothesis, we examined Na+ transport and tubular diameter in response to different flow rates during the microperfusion of isolated S2 proximal tubules from mouse kidneys. The data were analyzed by using a mathematical model to estimate the microvillous torque as function of flow. In this model, increases in luminal diameter have the effect of blunting the impact of flow velocity on microvillous shear stress and, thus, microvillous torque. We found that variations in microvillous torque produce nearly identical fractional changes in Na+ reabsorption. Furthermore, the flow-dependent Na+ transport is increased by increasing luminal fluid viscosity, diminished in Na+-H+ exchanger isoform 3 knockout mice, and abolished by nontoxic disruption of the actin cytoskeleton. These data support our hypothesis that the “brush-border” microvilli serve a mechanosensory function in which fluid dynamic torque is transmitted to the actin cytoskeleton and modulates Na+ absorption in kidney proximal tubules. PMID:15319475

  19. Workbook on Identification of Aedes Aegypti Larvae.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; And Others

    This self-instructional booklet is designed to enable yellow fever control workers to identify the larvae of "Aedes aegypti." The morphological features of mosquito larvae are illustrated in this partially programed text, and the distinguishing features of "A. aegypti" indicated. A glossary is included. (AL)

  20. The metabolic fate of lactate in renal cortical tubules

    PubMed Central

    Janssens, Peter; Hems, Reg; Ross, Brian

    1980-01-01

    1. Isolated kidney cortex tubules prepared from fed rats and incubated with near-physiological concentrations of [14C]lactate decrease the specific radioactivity of the added lactate. This effect may be attributable to at least two mechanisms; formation of lactate from endogenous precursors, or entry of unlabelled carbon into the lactate pool as a result of substrate cycling, via phosphoenolpyruvate, pyruvate and oxaloacetate, together with equilibration of the oxaloacetate pool with malate and fumarate. Such substrate cycling could occur within a single cell, or between two populations of different cells, one glycolytic and the other gluconeogenic. These possibilities have been investigated by using metabolic inhibitors or alternative metabolic substrates. 2. Tubules from fed rats produced a fall in specific radioactivity of 14.4% when incubated for 40min with 2mm-lactate alone. A mathematical treatment of this result is presented, which allows the rate of fall in specific radioactivity to be expressed as the addition of unlabelled lactate to the pool. This corresponds to a rate of formation of unlabelled lactate of 121±22μmol/h per g dry wt., a rate close to that of gluconeogenesis. In tubules from fasting rats, there was no reduction of the specific radioactivity of lactate, indicating that fasting for 24h suppresses production of unlabelled-lactate carbon. 3. Addition of 2mm-fumarate resulted in a significantly greater decrease in the specific radioactivity of lactate, but aspartate (2mm), malate (2mm) and glucose (5mm) were without effect. Total inhibition of gluconeogenesis with 3-mercaptopicolinate did not prevent the fall in specific radioactivity of lactate observed in tubules from fed-rat kidney, thereby excluding significant activity of the substrate cycle pyruvate→oxaloacetate→phosphoenolpyruvate→pyruvate. 4. The capacity of pyruvate kinase under the test conditions in tubules prepared from kidneys of fed or starved rats was at least ten times

  1. Distribution, abundance and bionomics of Aedes albopictus in southern Texas.

    PubMed

    Womack, M L

    1993-09-01

    A survey was conducted for Aedes albopictus in southern Texas during the summer of 1992. Thirty-five new country records were added to the distribution of this imported mosquito in Texas. Aedes albopictus was widely distributed throughout the ecological regions in the survey area, but its abundance decreased in counties adjacent to the Rio Grande River. However, these counties had high densities of Aedes aegypti. PMID:8245952

  2. Proteomic analysis of the plasma membrane-movement tubule complex of cowpea mosaic virus.

    PubMed

    den Hollander, Paulus W; de Sousa Geraldino Duarte, Priscilla; Bloksma, Hanke; Boeren, Sjef; van Lent, Jan W M

    2016-05-01

    Cowpea mosaic virus forms tubules constructed from the movement protein (MP) in plasmodesmata (PD) to achieve cell-to-cell movement of its virions. Similar tubules, delineated by the plasma membrane (PM), are formed protruding from the surface of infected protoplasts. These PM-tubule complexes were isolated from protoplasts by immunoprecipitation and analysed for their protein content by tandem mass spectrometry to identify host proteins with affinity for the movement tubule. Seven host proteins were abundantly present in the PM-tubule complex, including molecular chaperonins and an AAA protein. Members of both protein families have been implicated in establishment of systemic infection. The potential role of these proteins in tubule-guided cell-cell transport is discussed. PMID:26780773

  3. Hemocyte-Secreted Type IV Collagen Enhances BMP Signaling to Guide Renal Tubule Morphogenesis in Drosophila

    PubMed Central

    Bunt, Stephanie; Hooley, Clare; Hu, Nan; Scahill, Catherine; Weavers, Helen; Skaer, Helen

    2010-01-01

    Summary Details of the mechanisms that determine the shape and positioning of organs in the body cavity remain largely obscure. We show that stereotypic positioning of outgrowing Drosophila renal tubules depends on signaling in a subset of tubule cells and results from enhanced sensitivity to guidance signals by targeted matrix deposition. VEGF/PDGF ligands from the tubules attract hemocytes, which secrete components of the basement membrane to ensheath them. Collagen IV sensitizes tubule cells to localized BMP guidance cues. Signaling results in pathway activation in a subset of tubule cells that lead outgrowth through the body cavity. Failure of hemocyte migration, loss of collagen IV, or abrogation of BMP signaling results in tubule misrouting and defective organ shape and positioning. Such regulated interplay between cell-cell and cell-matrix interactions is likely to have wide relevance in organogenesis and congenital disease. PMID:20708591

  4. Recycling endosome tubule morphogenesis from sorting endosomes requires the kinesin motor KIF13A

    PubMed Central

    Delevoye, Cédric; Miserey-Lenkei, Stéphanie; Montagnac, Guillaume; Gilles-Marsens, Floriane; Paul-Gilloteaux, Perrine; Giordano, Francesca; Waharte, François; Marks, Michael S.; Goud, Bruno; Raposo, Graça

    2014-01-01

    Summary Early endosomes consist of vacuolar sorting and tubular recycling domains that segregate components fated for degradation in lysosomes or reuse by recycling to the plasma membrane or Golgi. The tubular transport intermediates that constitute recycling endosomes function in cell polarity, migration and cytokinesis. Endosomal tubulation and fission require both actin and intact microtubules, but while factors that stabilize recycling endosomal tubules have been identified, those required for tubule generation from vacuolar sorting endosomes remain unknown. We show that the microtubule motor KIF13A associates with recycling endosome tubules and controls their morphogenesis. Interfering with KIF13A function impairs the formation of endosomal tubules from sorting endosomes with consequent defects in endosome homeostasis and cargo recycling. Moreover, KIF13A interacts and cooperates with RAB11 to generate endosomal tubules. Our data illustrate how a microtubule motor couples early endosome morphogenesis to its motility and function. PMID:24462287

  5. MODELING PROXIMAL TUBULE CELL HOMEOSTASIS: TRACKING CHANGES IN LUMINAL FLOW

    PubMed Central

    Weinstein, Alan M.; Sontag, Eduardo D.

    2009-01-01

    During normal kidney function, there are are routinely wide swings in proximal tubule fluid flow and proportional changes in Na+ reabsorption across tubule epithelial cells. This "glomerulotubular balance" occurs in the absence of any substantial change in cell volume, and is thus a challenge to coordinate luminal membrane solute entry with peritubular membrane solute exit. In this work, linear optimal control theory is applied to generate a configuration of regulated transporters that could achieve this result. A previously developed model of rat proximal tubule epithelium is linearized about a physiologic reference condition; the approximate linear system is recast as a dynamical system; and a Riccati equation is solved to yield the optimal linear feedback that stabilizes Na+ flux, cell volume, and cell pH. The first observation is that optimal feedback control is largely consigned to three physiologic variables, cell volume, cell electrical potential, and lateral intercellular hydrostatic pressure. Parameter modulation by cell volume stabilizes cell volume; parameter modulation by electrical potential or interspace pressure act to stabilize Na+ flux and cell pH. This feedback control is utilized in a tracking problem, in which reabsorptive Na+ flux varies over a factor of two. The resulting control parameters consist of two terms, an autonomous term and a feedback term, and both terms include transporters on both luminal and peritubular cell membranes. Overall, the increase in Na+ flux is achieved with upregulation of luminal Na+/H+ exchange and Na+-glucose cotransport, with increased peritubular Na+−3HCO3− and K+ − Cl− cotransport, and with increased Na+, K+-ATPase activity. The configuration of activated transporters emerges as testable hypothesis of the molecular basis for glomerulotubular balance. It is suggested that the autonomous control component at each cell membrane could represent the cytoskeletal effects of luminal flow. PMID:19280266

  6. Triacylglycerol metabolism in isolated rat kidney cortex tubules.

    PubMed

    Wirthensohn, G; Guder, W G

    1980-01-15

    Triacylglycerol metabolism has been studied in kidney cortex tubules from starved rats, prepared by collagenase treatment. Triacylglycerol was determined by a newly developed fully enzymic method. Incubation of tubules in the absence of fatty acids led to a decrease of endogenous triacylglycerol by about 50% in 1h. Addition of albuminbound oleate or palmitate resulted in a steady increase of tissue triacylglycerol over 2h. The rate of triacylglycerol synthesis was linearly dependent on oleate concentration up to 0.8mm, reaching a saturation at higher concentrations. Triacylglycerol formation from palmitate was less than that from oleate. This difference was qualitatively the same when net synthesis was compared with incorporation of labelled fatty acids. Quantitatively, however, the difference was less with the incorporation technique. Gluconeogenic substrates, which by themselves had no effect on triacylglycerol concentrations, stimulated neutral lipid formation from fatty acids. Glucose and lysine did not have such a stimulatory effect. Inhibition of gluconeogenesis from lactate by mercaptopicolinic acid likewise inhibited triacylglycerol formation. This inhibitory effect was seen with oleate as well as with oleate plus lactate. When [2-(14)C]lactate was used the incorporation of label into triacylglycerol was found in the glycerol moiety exclusively. Addition of dl-beta-hydroxybutyrate (5mm) to the incubation medium in the presence of oleate or oleate plus lactate led to a significant increase in triacylglycerol formation. In contrast with the gluconeogenic substrates, dl-beta-hydroxybutyrate had no stimulatory effect on fatty acid uptake. The results suggest that renal triacylglycerol formation is a quantitatively important metabolic process. The finding that gluconeogenic substrates, but not glucose, increase lipid formation, indicates that the glycerol moiety is formed by glyceroneogenesis in the proximal tubules. The effect of ketone bodies seems to be

  7. Variable t-tubule organization and Ca2+ homeostasis across the atria.

    PubMed

    Frisk, Michael; Koivumäki, Jussi T; Norseng, Per A; Maleckar, Mary M; Sejersted, Ole M; Louch, William E

    2014-08-15

    Although t-tubules have traditionally been thought to be absent in atrial cardiomyocytes, recent studies have suggested that t-tubules exist in the atria of large mammals. However, it is unclear whether regional differences in t-tubule organization exist that define cardiomyocyte function across the atria. We sought to investigate regional t-tubule density in pig and rat atria and the consequences for cardiomyocyte Ca(2+) homeostasis. We observed t-tubules in approximately one-third of rat atrial cardiomyocytes, in both tissue cryosections and isolated cardiomyocytes. In a minority (≈10%) of atrial cardiomyocytes, the t-tubular network was well organized, with a transverse structure resembling that of ventricular cardiomyocytes. In both rat and pig atrial tissue, we observed higher t-tubule density in the epicardium than in the endocardium. Consistent with high variability in the distribution of t-tubules and Ca(2+) channels among cells, L-type Ca(2+) current amplitude was also highly variable and steeply dependent on capacitance and t-tubule density. Accordingly, Ca(2+) transients showed great variability in Ca(2+) release synchrony. Simultaneous imaging of the cell membrane and Ca(2+) transients confirmed t-tubule functionality. Results from mathematical modeling indicated that a transmural gradient in t-tubule organization and Ca(2+) release kinetics supports synchronization of contraction across the atrial wall and may underlie transmural differences in the refractory period. In conclusion, our results indicate that t-tubule density is highly variable across the atria. We propose that higher t-tubule density in cells localized in the epicardium may promote synchronization of contraction across the atrial wall. PMID:24951751

  8. Use of Poly (Amidoamine) Dendrimer for Dentinal Tubule Occlusion: A Preliminary Study

    PubMed Central

    Wang, Tianda; Yang, Sheng; Wang, Lei; Feng, Hailan

    2015-01-01

    The occlusion of dentinal tubules is an effective method to alleviate the symptoms caused by dentin hypersensitivity, a significant health problem in dentistry and daily life. The in situ mineralization within dentinal tubules is a promising treatment for dentin hypersensitivity as it induces the formation of mineral on the sensitive regions and occludes the dentinal tubules. This study was carried out to evaluate the in vitro effect of a whole generation poly(amidoamine) (PAMAM) dendrimer (G3.0) on dentinal tubule occlusion by inducing mineralization within dentinal tubules. Dentin discs were treated with PAMAM dendrimers using two methods, followed by the in vitro characterization using Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). These results showed that G3.0 PAMAM dendrimers coated on dentin surface and infiltrated in dentinal tubules could induce hydroxyapatite formation and resulted in effective dentinal tubule occlusion. Moreover, crosslinked PAMAM dendrimers could induce the remineralization of demineralized dentin and thus had the potential in dentinal tubule occlusion. In this in vitro study, dentinal tubules occlusion could be achieved by using PAMAM dendrimers. This could lead to the development of a new therapeutic technique for the treatment of dentin hypersensitivity. PMID:25885090

  9. Use of poly (amidoamine) dendrimer for dentinal tubule occlusion: a preliminary study.

    PubMed

    Wang, Tianda; Yang, Sheng; Wang, Lei; Feng, Hailan

    2015-01-01

    The occlusion of dentinal tubules is an effective method to alleviate the symptoms caused by dentin hypersensitivity, a significant health problem in dentistry and daily life. The in situ mineralization within dentinal tubules is a promising treatment for dentin hypersensitivity as it induces the formation of mineral on the sensitive regions and occludes the dentinal tubules. This study was carried out to evaluate the in vitro effect of a whole generation poly(amidoamine) (PAMAM) dendrimer (G3.0) on dentinal tubule occlusion by inducing mineralization within dentinal tubules. Dentin discs were treated with PAMAM dendrimers using two methods, followed by the in vitro characterization using Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). These results showed that G3.0 PAMAM dendrimers coated on dentin surface and infiltrated in dentinal tubules could induce hydroxyapatite formation and resulted in effective dentinal tubule occlusion. Moreover, crosslinked PAMAM dendrimers could induce the remineralization of demineralized dentin and thus had the potential in dentinal tubule occlusion. In this in vitro study, dentinal tubules occlusion could be achieved by using PAMAM dendrimers. This could lead to the development of a new therapeutic technique for the treatment of dentin hypersensitivity. PMID:25885090

  10. Discerning the role of mechanosensors in regulating proximal tubule function.

    PubMed

    Raghavan, Venkatesan; Weisz, Ora A

    2016-01-01

    All cells in the body experience external mechanical forces such as shear stress and stretch. These forces are sensed by specialized structures in the cell known as mechanosensors. Cells lining the proximal tubule (PT) of the kidney are continuously exposed to variations in flow rates of the glomerular ultrafiltrate, which manifest as changes in axial shear stress and radial stretch. Studies suggest that these cells respond acutely to variations in flow by modulating their ion transport and endocytic functions to maintain glomerulotubular balance. Conceptually, changes in the axial shear stress in the PT could be sensed by three known structures, namely, the microvilli, the glycocalyx, and primary cilia. The orthogonal component of the force produced by flow exhibits as radial stretch and can cause expansion of the tubule. Forces of stretch are transduced by integrins, by stretch-activated channels, and by cell-cell contacts. This review summarizes our current understanding of flow sensing in PT epithelia, discusses challenges in dissecting the role of individual flow sensors in the mechanosensitive responses, and identifies potential areas of opportunity for new study. PMID:26662200

  11. Acid-base transport by the renal proximal tubule

    PubMed Central

    Skelton, Lara A.; Boron, Walter F.; Zhou, Yuehan

    2015-01-01

    Each day, the kidneys filter 180 L of blood plasma, equating to some 4,300 mmol of the major blood buffer, bicarbonate (HCO3−). The glomerular filtrate enters the lumen of the proximal tubule (PT), and the majority of filtered HCO3− is reclaimed along the early (S1) and convoluted (S2) portions of the PT in a manner coupled to the secretion of H+ into the lumen. The PT also uses the secreted H+ to titrate non-HCO3− buffers in the lumen, in the process creating “new HCO3−” for transport into the blood. Thus, the PT – along with more distal renal segments – is largely responsible for regulating plasma [HCO3−]. In this review we first focus on the milestone discoveries over the past 50+ years that define the mechanism and regulation of acid-base transport by the proximal tubule. Further on in the review, we will summarize research still in progress from our laboratory, work that addresses the problem of how the PT is able to finely adapt to acid–base disturbances by rapidly sensing changes in basolateral levels of HCO3− and CO2 (but not pH), and thereby to exert tight control over the acid–base composition of the blood plasma. PMID:21170887

  12. Adenosine, type 1 receptors: role in proximal tubule Na+ reabsorption.

    PubMed

    Welch, W J

    2015-01-01

    Adenosine type 1 receptor (A1 -AR) antagonists induce diuresis and natriuresis in experimental animals and humans. Much of this effect is due to inhibition of A1 -ARs in the proximal tubule, which is responsible for 60-70% of the reabsorption of filtered Na(+) and fluid. Intratubular application of receptor antagonists indicates that A1 -AR mediates a portion of Na(+) uptake in PT and PT cells, via multiple transport systems, including Na(+) /H(+) exchanger-3 (NHE3), Na(+) /PO4(-) co-transporter and Na(+) -dependent glucose transporter, SGLT. Renal microperfusion and recollection studies have shown that fluid reabsorption is reduced by A1 -AR antagonists and is lower in A1 -AR KO mice, compared to WT mice. Absolute proximal reabsorption (APR) measured by free-flow micropuncture is equivocal, with studies that show either lower APR or similar APR in A1 -AR KO mice, compared to WT mice. Inhibition of A1 -ARs lowers elevated blood pressure in models of salt-sensitive hypertension, partially due to their effects in the proximal tubule. PMID:25345761

  13. Cell osmotic water permeability of isolated rabbit proximal convoluted tubules.

    PubMed

    Carpi-Medina, P; González, E; Whittembury, G

    1983-05-01

    Cell osmotic water permeability, Pcos, of the peritubular aspect of the proximal convoluted tubule (PCT) was measured from the time course of cell volume changes subsequent to the sudden imposition of an osmotic gradient, delta Cio, across the cell membrane of PCT that had been dissected and mounted in a chamber. The possibilities of artifact were minimized. The bath was vigorously stirred, the solutions could be 95% changed within 0.1 s, and small osmotic gradients (10-20 mosM) were used. Thus, the osmotically induced water flow was a linear function of delta Cio and the effect of the 70-microns-thick unstirred layers was negligible. In addition, data were extrapolated to delta Cio = 0. Pcos for PCT was 41.6 (+/- 3.5) X 10(-4) cm3 X s-1 X osM-1 per cm2 of peritubular basal area. The standing gradient osmotic theory for transcellular osmosis is incompatible with this value. Published values for Pcos of PST are 25.1 X 10(-4), and for the transepithelial permeability Peos values are 64 X 10(-4) for PCT and 94 X 10(-4) for PST, in the same units. These results indicate that there is room for paracellular water flow in both nephron segments and that the magnitude of the transcellular and paracellular water flows may vary from one segment of the proximal tubule to another. PMID:6846543

  14. Expression of Bcl-2 and Bax in Mouse Renal Tubules during Kidney Development

    PubMed Central

    Song, Xiao-Feng; Ren, Hao; Andreasen, Arne; Thomsen, Jesper Skovhus; Zhai, Xiao-Yue

    2012-01-01

    Bcl-2 and Bax play an important role in apoptosis regulation, as well as in cell adhesion and migration during kidney morphogenesis, which is structurally and functionally related to mitochondria. In order to elucidate the role of Bcl-2 and Bax during kidney development, it is essential to establish the exact location of their expression in the kidney. The present study localized their expression during kidney development. Kidneys from embryonic (E) 16-, 17-, 18-day-old mouse fetuses, and postnatal (P) 1-, 3-, 5-, 7-, 14-, 21-day-old pups were embedded in Epon. Semi-thin serial sections from two E17 kidneys underwent computer assisted 3D tubule tracing. The tracing was combined with a newly developed immunohistochemical technique, which enables immunohistochemistry on glutaraldehyde fixated plastic embedded sections. Thereby, the microstructure could be described in detail, and the immunochemistry can be performed using exactly the same sections. The study showed that Bcl-2 and Bax were strongly expressed in mature proximal convoluted tubules at all time points, less strongly expressed in proximal straight tubules, and only weakly in immature proximal tubules and distal tubules. No expression was detected in ureteric bud and other earlier developing structures, such as comma bodies, S shaped bodies, glomeruli, etc. Tubules expressing Bcl-2 only were occasionally observed. The present study showed that, during kidney development, Bcl-2 and Bax are expressed differently in the proximal and distal tubules, although these two tubule segments are almost equally equipped with mitochondria. The functional significance of the different expression of Bcl-2 and Bax in proximal and distal tubules is unknown. However, the findings of the present study suggest that the mitochondrial function differs between mature proximal tubules and in the rest of the tubules. The function of Bcl-2 and Bax during tubulogenesis still needs to be investigated. PMID:22389723

  15. Cardiac BIN1 folds T-tubule membrane, controlling ion flux and limiting arrhythmia.

    PubMed

    Hong, TingTing; Yang, Huanghe; Zhang, Shan-Shan; Cho, Hee Cheol; Kalashnikova, Mariya; Sun, Baiming; Zhang, Hao; Bhargava, Anamika; Grabe, Michael; Olgin, Jeffrey; Gorelik, Julia; Marbán, Eduardo; Jan, Lily Y; Shaw, Robin M

    2014-06-01

    Cardiomyocyte T tubules are important for regulating ion flux. Bridging integrator 1 (BIN1) is a T-tubule protein associated with calcium channel trafficking that is downregulated in failing hearts. Here we find that cardiac T tubules normally contain dense protective inner membrane folds that are formed by a cardiac isoform of BIN1. In mice with cardiac Bin1 deletion, T-tubule folding is decreased, which does not change overall cardiomyocyte morphology but leads to free diffusion of local extracellular calcium and potassium ions, prolonging action-potential duration and increasing susceptibility to ventricular arrhythmias. We also found that T-tubule inner folds are rescued by expression of the BIN1 isoform BIN1+13+17, which promotes N-WASP-dependent actin polymerization to stabilize the T-tubule membrane at cardiac Z discs. BIN1+13+17 recruits actin to fold the T-tubule membrane, creating a 'fuzzy space' that protectively restricts ion flux. When the amount of the BIN1+13+17 isoform is decreased, as occurs in acquired cardiomyopathy, T-tubule morphology is altered, and arrhythmia can result. PMID:24836577

  16. Mathematical study on robust tissue pattern formation in growing epididymal tubule.

    PubMed

    Hirashima, Tsuyoshi

    2016-10-21

    Tissue pattern formation during development is a reproducible morphogenetic process organized by a series of kinetic cellular activities, leading to the building of functional and stable organs. Recent studies focusing on mechanical aspects have revealed physical mechanisms on how the cellular activities contribute to the formation of reproducible tissue patterns; however, the understanding for what factors achieve the reproducibility of such patterning and how it occurs is far from complete. Here, I focus on a tube pattern formation during murine epididymal development, and show that two factors influencing physical design for the patterning, the proliferative zone within the tubule and the viscosity of tissues surrounding to the tubule, control the reproducibility of epididymal tubule pattern, using a mathematical model based on experimental data. Extensive numerical simulation of the simple mathematical model revealed that a spatially localized proliferative zone within the tubule, observed in experiments, results in more reproducible tubule pattern. Moreover, I found that the viscosity of tissues surrounding to the tubule imposes a trade-off regarding pattern reproducibility and spatial accuracy relating to the region where the tubule pattern is formed. This indicates an existence of optimality in material properties of tissues for the robust patterning of epididymal tubule. The results obtained by numerical analysis based on experimental observations provide a general insight on how physical design realizes robust tissue pattern formation. PMID:27396360

  17. Cardiac Spliced BIN1 Folds T-tubule Membrane, Controlling Ion Flux and Limiting Arrhythmia

    PubMed Central

    Hong, TingTing; Yang, Huanghe; Zhang, Shan-Shan; Cho, Hee Cheol; Kalashnikova, Mariya; Sun, Baiming; Zhang, Hao; Bhargava, Anamika; Grabe, Michael; Olgin, Jeffrey; Gorelik, Julia; Marbán, Eduardo; Jan, Lily Y.; Shaw, Robin M.

    2014-01-01

    Cardiomyocyte T-tubules are important for regulating ionic flux. Bridging Integrator 1 (BIN1) is a T-tubule protein associated with calcium channel trafficking that is down-regulated in failing hearts. Here we find that cardiac T-tubules normally contain dense protective inner membrane folds that are formed by a cardiac spliced isoform of BIN1. In mice with cardiac Bin1 deletion, T-tubule folding is decreased which does not change overall cardiomyocyte morphology, but frees diffusion of local extracellular calcium and potassium ions, prolonging action potential duration, and increasing susceptibility to ventricular arrhythmias. We also find that T-tubule inner folds are rescued only by the BIN1 isoform BIN1+13+17, which promotes N-WASP dependent actin polymerization to stabilize T-tubule membrane at cardiac Z-discs. In conclusion, BIN1+13+17 recruits actin to fold T-tubule membrane, creating a fuzzy space that protectively restricts ionic flux. When BIN1+13+17 is decreased, as occurs in acquired cardiomyopathy, T-tubule morphology is altered and arrhythmias can result. PMID:24836577

  18. Behavioral responses of two dengue virus vectors, Aedes aegypti and Aedes albopictus (Diptera: Culicidae), to DUET TM and its components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ultralow volume (ULV) droplets of DUET TM, prallethrin and sumithrin at a sublethal dose were applied to unfed (non bloodfed) and bloodfed female Aedes aegypti Linn. and Aedes albopictus (Skuse) in a wind tunnel. Control spray droplets only contained inactive ingredients. Individual mosquitoes wer...

  19. Laboratory evaluation of the response of Aedes aegypti and Aedes albopictus uninfected and infected with dengue virus to deet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laboratory studies were conducted to compare the response of Aedes aegypti (L.) and Aedes albopictus (Skuse) adults, uninfected and infected with four serotypes of dengue virus, to a repellent containing 5% deet. The results showed that mosquitoes infected with the four serotypes of dengue respond i...

  20. Asymmetric Mating Interference between Two Related Mosquito Species: Aedes (Stegomyia) albopictus and Aedes (Stegomyia) cretinus

    PubMed Central

    Giatropoulos, Athanassios; Papachristos, Dimitrios P.; Koliopoulos, George; Michaelakis, Antonios; Emmanouel, Nickolaos

    2015-01-01

    Aedes (Stegomyia) albopictus (Skuse) and Aedes (Stegomyia) cretinus Edwards are closely related mosquito species with common morphological features and bio-ecological similarities. Recent mosquito surveillance in Athens, Greece, showed that they are sympatric mosquito species, with Ae. Albopictus developing quite higher population densities than Ae. Cretinus. The potential of mating interference between these species was investigated by reciprocal and homologous mating experiments in cages under laboratory conditions. In non-choice interspecific crosses (groups of males and females) females of both species produced sterile eggs. Insemination rate was 58% for Ae. Cretinus females and only 1% for Ae. Albopictus females. Aedes albopictus males were sexually aggressive and inseminated Ae. Cretinus females (31%) in choice experiments, where males of one species had access to mate with females of both species. Whereas, interspecific mating of Ae. Albopictus females with Ae. Cretinus males in the co-occurrence of Ae. Cretinus females was weaker (4%). Aedes cretinus females from non-choice crossing with Ae. Albopictus or Ae. Cretinus males were paired individually with conspecific males. The percentage of fertile Ae. Cretinus females was 17.5% when had encaged before with Ae. Albopictus males, compared to 100% when Ae. Cretinus females were encaged with conspecific males only. Probable ecological consequences of asymmetric mating between these ecologically homologous species in nature are discussed. PMID:26001099

  1. A second form of infectious bursal disease virus-associated tubule contains VP4.

    PubMed Central

    Granzow, H; Birghan, C; Mettenleiter, T C; Beyer, J; Köllner, B; Mundt, E

    1997-01-01

    Preparations of density gradient-purified infectious bursal disease virus (IBDV) were found to contain full and empty icosahedral virions, type I tubules with a diameter of about 60 nm, and type II tubules 24 to 26 nm in diameter. By immunoelectron microscopy we demonstrate that virions and both types of tubular structures specifically react with anti-IBDV serum. In infected cells intracytoplasmic and intranuclear type II tubules reacted exclusively with an anti-VP4 monoclonal antibody, as did type II tubules in virion preparations. The immunofluorescence pattern with the anti-VP4 antibody correlated with electron microscopical findings. Neither purified extracellular nor intracellular virions were labeled with the anti-VP4 MAb. Our data show that the type II tubules contain VP4 and suggest that VP4 is not part of the virus particle. PMID:9343252

  2. Methods for analyzing the role of phospholipase A2 enzymes in endosome membrane tubule formation

    PubMed Central

    Kalkofen, Danielle N.; de Figueiredo, Paul; Brown, William J.

    2016-01-01

    Cargo export from mammalian endosomal compartments often involves membrane tubules, into which soluble and membrane-bound cargos are segregated for subsequent intracellular transport. These membrane tubules are highly dynamic and their formation is mediated by a variety of endosome-associated proteins. However, little is known about how these membrane tubules are temporally or spatially regulated, so other tubule-associated proteins are likely to be discovered and analyzed. Therefore, methods to examine the biogenesis and regulation of endosome membrane tubules will prove to be valuable for cell biologists. In this chapter, we describe methods for studying this process using both cell-free, in vitro reconstitution assays, and in vivo image analysis tools. PMID:26360034

  3. The structure and function of cardiac t-tubules in health and disease.

    PubMed

    Ibrahim, Michael; Gorelik, Julia; Yacoub, Magdi H; Terracciano, Cesare M

    2011-09-22

    The transverse tubules (t-tubules) are invaginations of the cell membrane rich in several ion channels and other proteins devoted to the critical task of excitation-contraction coupling in cardiac muscle cells (cardiomyocytes). They are thought to promote the synchronous activation of the whole depth of the cell despite the fact that the signal to contract is relayed across the external membrane. However, recent work has shown that t-tubule structure and function are complex and tightly regulated in healthy cardiomyocytes. In this review, we outline the rapidly accumulating knowledge of its novel roles and discuss the emerging evidence of t-tubule dysfunction in cardiac disease, especially heart failure. Controversy surrounds the t-tubules' regulatory elements, and we draw attention to work that is defining these elements from the genetic and the physiological levels. More generally, this field illustrates the challenges in the dissection of the complex relationship between cellular structure and function. PMID:21697171

  4. Fine structure of the sperm storage tubules in the box turtle oviduct.

    PubMed

    Gist, D H; Fischer, E N

    1993-03-01

    The sperm storage tubules of the box turtle (Terrapene carolina) were examined by transmission electron microscopy. Tubules containing spermatozoa were surrounded by 6-8 secretory cells, each of which contains numerous membrane-bound vesicles presumably containing precursors to egg white proteins. The apical membranes of these cells contain microvilli, and the apical lateral membranes possess prominent junctional complexes. Cells comprising the spermatozoa-containing tubules cannot be differentiated from those devoid of spermatozoa. Various quantities of spermatozoa reside free in the lumina of the secretory tubules, and are not in contact with host cells. Only the presence of ducts communicating with the oviduct lumen serve to differentiate the spermatozoa-containing tubules. PMID:8501716

  5. Do t-tubules play a role in arrhythmogenesis in cardiac ventricular myocytes?

    PubMed

    Orchard, C H; Bryant, S M; James, A F

    2013-09-01

    The transverse (t-) tubules of mammalian ventricular myocytes are invaginations of the surface membrane. The function of many of the key proteins involved in excitation-contraction coupling is located predominantly at the t-tubules, which thus form a Ca(2+)-handling micro-environment that is central to the normal rapid activation and relaxation of the ventricular myocyte. Although cellular arrhythmogenesis shares many ion flux pathways with normal excitation-contraction coupling, the role of the t-tubules in such arrhythmogenesis has not previously been considered. In this brief review we consider how the location and co-location of proteins at the t-tubules may contribute to the generation of arrhythmogenic delayed and early afterdepolarisations, and how the loss of t-tubules that occurs during heart failure may alter the generation of such arrhythmias, as well as contributing to other types of arrhythmia as a result of changes of electrical heterogeneity within the whole heart. PMID:23652596

  6. A new look at electrolyte transport in the distal tubule.

    PubMed

    Eladari, Dominique; Chambrey, Régine; Peti-Peterdi, Janos

    2012-01-01

    The distal nephron plays a critical role in the renal control of homeostasis. Until very recently most studies focused on the control of Na(+), K(+), and water balance by principal cells of the collecting duct and the regulation of solute and water by hormones from the renin-angiotensin-aldosterone system and by antidiuretic hormone. However, recent studies have revealed the unexpected importance of renal intercalated cells, a subtype of cells present in the connecting tubule and collecting ducts. Such cells were thought initially to be involved exclusively in acid-base regulation. However, it is clear now that intercalated cells absorb NaCl and K(+) and hence may participate in the regulation of blood pressure and potassium balance. The second paradigm-challenging concept we highlight is the emerging importance of local paracrine factors that play a critical role in the renal control of water and electrolyte balance. PMID:21888509

  7. A New Look at Electrolyte Transport in the Distal Tubule

    PubMed Central

    Eladari, Dominique; Chambrey, Régine; Peti-Peterdi, Janos

    2015-01-01

    The distal nephron plays a critical role in the renal control of homeostasis. Until very recently most studies focused on the control of Na+, K+, and water balance by principal cells of the collecting duct and the regulation of solute and water by hormones from the renin-angiotensin-aldosterone system and by antidiuretic hormone. However, recent studies have revealed the unexpected importance of renal intercalated cells, a subtype of cells present in the connecting tubule and collecting ducts. Such cells were thought initially to be involved exclusively in acid-base regulation. However, it is clear now that intercalated cells absorb NaCl and K+ and hence may participate in the regulation of blood pressure and potassium balance. The second paradigm-challenging concept we highlight is the emerging importance of local paracrine factors that play a critical role in the renal control of water and electrolyte balance. PMID:21888509

  8. Regional variation in root dentinal tubule infection by Streptococcus gordonii.

    PubMed

    Love, R M

    1996-06-01

    The purpose of this study was to investigate the pattern of bacterial invasion of dentinal tubules at different regions in human roots. Specimens were obtained from single-rooted teeth that had their root canals prepared in a standard manner. Roots were then sectioned longitudinally through the canals and the resulting specimens chemically treated to remove the smear layers. Specimens were immersed in a suspension of Streptococcus gordonii for 3 weeks and then prepared for histological analysis. Sections from the cervical, midroot, and apical areas were examined. The pattern of bacterial infection of the cervical and midroot areas was similar, characterized as a heavy infection with bacteria penetrating as deep as 200 microns. Invasion of the apical dentin was significantly different, with a mild infection and maximum penetration of 60 microns. PMID:8934987

  9. Cadmium transport and toxicity in isolated perfused renal proximal tubules

    SciTech Connect

    Robinson, M.E.K.

    1991-01-01

    Cadmium is a potent toxicant preferentially accumulated in the renal cortex of humans and other animals. To assess the renal toxicity of inorganic cadmium, isolated segments (S1, S2, and S3) of rabbit renal proximal tubules were perfused with various concentrations of unlabeled cadmium chloride (CdCl[sub 2]) and a vital dye (FD C green). The tubular epithelial cells were observed under the light microscope for cellular injury and necrosis. Cellular swelling, luminal membrane blebbing, and cellular vacuolization were indicators of cellular injury, and dye uptake was indicative of cellular necrosis. To determine lumen-to-bath transport rates for cadmium, the segments were perfused with a mixture of [sup 109]CdCl[sub 2] and [sup 3]H-L-glucose; unlabeled CdCl[sub 2] was added when necessary to vary the total cadmium concentration from 1.5 [mu]M to 2000 [mu]M. Immediately after perfusion the tubules were extracted with 3% trichoroacetic acid (TCA) or with a modified Ringer's buffer of reduced osmolality to determine the fate of the cadmium removed from the lumen. Based on the toxicant indicators, increased dye uptake, increased luminal membrane blebbing, and increased vacuole formation, as the cadmium concentration was increased, cadmium was found to show toxicity to renal tubular cells at concentrations greater than 500 [mu]M. In transport experiments, increasing the cadmium concentration causes an increase in the leak of L-glucose, also indicating toxicity. A clear imbalance exists between the rate of disappearance of cadmium from the lumen and the rate of appearance in the bath for all three tubular segments. Cadmium appears to bind cellular membrane proteins, but it is extractable with 3% TCA. Cadmium, like mercury, is taken up at the luminal membrane, but very little is transported through the basolateral membrane.

  10. SGLT2 Mediates Glucose Reabsorption in the Early Proximal Tubule

    PubMed Central

    Platt, Kenneth A.; Cunard, Robyn; Schroth, Jana; Whaley, Jean; Thomson, Scott C.; Koepsell, Hermann; Rieg, Timo

    2011-01-01

    Mutations in the gene encoding for the Na+-glucose co-transporter SGLT2 (SLC5A2) associate with familial renal glucosuria, but the role of SGLT2 in the kidney is incompletely understood. Here, we determined the localization of SGLT2 in the mouse kidney and generated and characterized SGLT2-deficient mice. In wild-type (WT) mice, immunohistochemistry localized SGLT2 to the brush border membrane of the early proximal tubule. Sglt2−/− mice had glucosuria, polyuria, and increased food and fluid intake without differences in plasma glucose concentrations, GFR, or urinary excretion of other proximal tubular substrates (including amino acids) compared with WT mice. SGLT2 deficiency did not associate with volume depletion, suggested by similar body weight, BP, and hematocrit; however, plasma renin concentrations were modestly higher and plasma aldosterone levels were lower in Sglt2−/− mice. Whole-kidney clearance studies showed that fractional glucose reabsorption was significantly lower in Sglt2−/− mice compared with WT mice and varied in Sglt2−/− mice between 10 and 60%, inversely with the amount of filtered glucose. Free-flow micropuncture revealed that for early proximal collections, 78 ± 6% of the filtered glucose was reabsorbed in WT mice compared with no reabsorption in Sglt2−/− mice. For late proximal collections, fractional glucose reabsorption was 93 ± 1% in WT and 21 ± 6% in Sglt2−/− mice, respectively. These results demonstrate that SGLT2 mediates glucose reabsorption in the early proximal tubule and most of the glucose reabsorption by the kidney, overall. This mouse model mimics and explains the glucosuric phenotype of individuals carrying SLC5A2 mutations. PMID:20616166

  11. Importance of adenosine triphosphate in phospholipase A2-induced rabbit renal proximal tubule cell injury.

    PubMed Central

    Nguyen, V D; Cieslinski, D A; Humes, H D

    1988-01-01

    The pathogenesis of ischemic renal tubular cell injury involves a complex interaction of different processes, including membrane phospholipid alterations and depletion of high-energy phosphate stores. To assess the role of membrane phospholipid changes due to activation of phospholipases in renal tubule cell injury, suspensions enriched in rabbit renal proximal tubule segments were incubated with exogenous phospholipase A2 (PLA2). Exogenous PLA2 did not produce any significant change in various metabolic parameters reflective of cell injury in control nonhypoxic preparations despite a significant decrease in phosphatidylethanolamine (PE) and moderate increases in lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE). In contrast, exogenous PLA2 treatment of hypoxic tubules resulted in a severe degree of cell injury, as demonstrated by marked declines in tubule K+ and ATP contents and significant decreases in tubule uncoupled respiratory rates, and was associated with significant phospholipid alterations, including marked declines in phosphatidylcholine (PC) and PE and significant rises in LPC, LPE, and free fatty acids (FFA). The injurious metabolic effects of exogenous PLA2 on hypoxic tubules were reversed by addition of ATP-MgCl2 to the tubules. The protective effect of ATP-MgCl2 was associated with increases in tubule PC and PE contents and declines in LPC, LPE, and FFA contents. These experiments thus indicate that an increase in exogenous PLA2 activity produces renal proximal tubule cell injury when cell ATP levels decline, at which point phospholipid resynthesis cannot keep pace with phospholipid degradation with resulting depletion of phospholipids and accumulation of lipid by-products. High-energy phosphate store depletion appears to be an important condition for exogenous PLA2 activity to induce renal tubule cell injury. PMID:3417866

  12. Aedes aegypti resistance to temephos in Argentina.

    PubMed

    Seccacini, Emilia; Lucia, Alejandro; Zerba, Eduardo; Licastro, Susana; Masuh, Hector

    2008-12-01

    Monitoring of resistance of Aedes aegypti to temephos was implemented in the provinces of Formosa and Misiones, Argentina, as a response to the need to improve the vigilance for the dengue vector in areas of high risk of dengue. Eggs collected in each locality were reared, and susceptibility to temephos was assayed using larval bioassays. A weak decrease in susceptibility of larvae to temephos was observed in Clorinda and Puerto Iguazú, indicating an incipient resistance with a resistance ratio of 3. No control failures have been observed yet, and this program should allow the early detection of a real problem in our country. PMID:19181076

  13. Infection persistence time of Aedes breeding habitats

    NASA Astrophysics Data System (ADS)

    Bicout, D. J.; Chalvet-Monfray, K.; Sabatier, P.

    2002-03-01

    The Aedes mosquito species are capable of maintaining the circulation of viruses only by the strategy of transovarial transmission and diapause of eggs. It is found that when the transovarial transmission is inhibited, the survival time of the presence of viruses in a given mosquito habitat is limited from above by the eggs lifetime. In contrast, when the transovarial transmission is turned on, the infection persistence time may largely exceed both the eggs lifetime and flooding period depending upon the production rate of infected eggs. We present a simple model allowing the derivation of analytical expressions of the infection persistence time.

  14. La Crosse Encephalitis Virus Infection in Field-Collected Aedes albopictus, Aedes japonicus, and Aedes triseriatus in Tennessee.

    PubMed

    Westby, Katie M; Fritzen, Charissa; Paulsen, Dave; Poindexter, Stephanie; Moncayo, Abelardo C

    2015-09-01

    La Crosse virus (LACV) is a mosquito-borne virus and a major cause of pediatric encephalitis in the USA. La Crosse virus emerged in Tennessee and other states in the Appalachian region in 1997. We investigated LACV infection rates and seasonal abundances of the native mosquito vector, Aedes triseriatus, and 2 recently introduced mosquito species, Ae. albopictus and Ae. japonicus, in an emerging disease focus in Tennessee. Mosquitoes were collected using multiple trapping methods specific for Aedes mosquitoes at recent human case sites. Mosquito pools were tested via reverse transcriptase-polymerase chain reaction (RT-PCR) of the S segment to detect multiple Bunyamwera and California serogroup viruses, including LACV, as well as real-time RT-PCR of the M segment. A total of 54 mosquito pools were positive, including wild-caught adult females and laboratory-reared adults, demonstrating transovarial transmission in all 3 species. Maximum likelihood estimates (per 1,000 mosquitoes) were 2.72 for Ae. triseriatus, 3.01 for Ae. albopictus, and 0.63 for Ae. japonicus. We conclude that Ae. triseriatus and Ae. albopictus are important LACV vectors and that Ae. japonicus also may be involved in virus maintenance and transmission. PMID:26375904

  15. First record of Aedes koreicus (Diptera: Culicidae) in Germany.

    PubMed

    Werner, Doreen; Zielke, Dorothee E; Kampen, Helge

    2016-03-01

    Within the framework of a national mosquito monitoring programme, a mosquito specimen collected in mid-2015 in southern Germany was identified as Aedes koreicus, a non-endemic species originating from East Asia. After the Asian bush mosquito Aedes japonicus, which is already established in Germany and widely distributed, and the Asian tiger mosquito Aedes albopictus, which is increasingly often introduced from southern Europe, A. koreicus is the third demonstrated invasive mosquito species in Germany supposed to have significant vector potential for disease agents. PMID:26614356

  16. A Non-sulfated Chondroitin Stabilizes Membrane Tubulation in Cnidarian Organelles*

    PubMed Central

    Adamczyk, Patrizia; Zenkert, Claudia; Balasubramanian, Prakash G.; Yamada, Shuhei; Murakoshi, Saori; Sugahara, Kazuyuki; Hwang, Jung Shan; Gojobori, Takashi; Holstein, Thomas W.; Özbek, Suat

    2010-01-01

    Membrane tubulation is generally associated with rearrangements of the cytoskeleton and other cytoplasmic factors. Little is known about the contribution of extracellular matrix components to this process. Here, we demonstrate an essential role of proteoglycans in the tubulation of the cnidarian nematocyst vesicle. The morphogenesis of this extrusive organelle takes place inside a giant post-Golgi vesicle, which topologically represents extracellular space. This process includes the formation of a complex collagenous capsule structure that elongates into a long tubule, which invaginates after its completion. We show that a non-sulfated chondroitin appears as a scaffold in early morphogenesis of all nematocyst types in Hydra and Nematostella. It accompanies the tubulation of the vesicle membrane forming a provisional tubule structure, which after invagination matures by collagen incorporation. Inhibition of chondroitin synthesis by β-xylosides arrests nematocyst morphogenesis at different stages of tubule outgrowth resulting in retention of tubule material and a depletion of mature capsules in the tentacles of hydra. Our data suggest a conserved role of proteoglycans in the stabilization of a membrane protrusion as an essential step in organelle morphogenesis. PMID:20538610

  17. Aldosterone and angiotensin II induce protein aggregation in renal proximal tubules

    PubMed Central

    Cheema, Muhammad U; Poulsen, Ebbe T; Enghild, Jan J; Hoorn, Ewout; Fenton, Robert A; Praetorius, Jeppe

    2013-01-01

    Renal tubules are highly active transporting epithelia and are at risk of protein aggregation due to high protein turnover and/or oxidative stress. We hypothesized that the risk of aggregation was increased upon hormone stimulation and assessed the state of the intracellular protein degradation systems in the kidney from control rats and rats receiving aldosterone or angiotensin II treatment for 7 days. Control rats formed both aggresomes and autophagosomes specifically in the proximal tubules, indicating a need for these structures even under baseline conditions. Fluorescence sorted aggresomes contained various rat keratins known to be expressed in renal tubules as assessed by protein mass spectrometry. Aldosterone administration increased the abundance of the proximal tubular aggresomal protein keratin 5, the ribosomal protein RPL27, ataxin-3, and the chaperone heat shock protein 70-4 with no apparent change in the aggresome–autophagosome markers. Angiotensin II induced aggregation of RPL27 specifically in proximal tubules, again without apparent change in antiaggregating proteins or the aggresome–autophagosome markers. Albumin endocytosis was unaffected by the hormone administration. Taken together, we find that the renal proximal tubules display aggresome formation and autophagy. Despite an increase in aggregation-prone protein load in these tubules during hormone treatment, renal proximal tubules seem to have sufficient capacity for removing protein aggregates from the cells. PMID:24303148

  18. In vivo model for microbial invasion of tooth root dentinal tubules

    PubMed Central

    BRITTAN, Jane L; SPRAGUE, Susan V; MACDONALD, Emma L; LOVE, Robert M; JENKINSON, Howard F; WEST, Nicola X

    2016-01-01

    ABSTRACT Objective Bacterial penetration of dentinal tubules via exposed dentine can lead to root caries and promote infections of the pulp and root canal system. The aim of this work was to develop a new experimental model for studying bacterial invasion of dentinal tubules within the human oral cavity. Material and Methods Sections of human root dentine were mounted into lower oral appliances that were worn by four human subjects for 15 d. Roots were then fixed, sectioned, stained and examined microscopically for evidence of bacterial invasion. Levels of invasion were expressed as Tubule Invasion Factor (TIF). DNA was extracted from root samples, subjected to polymerase chain reaction amplification of 16S rRNA genes, and invading bacteria were identified by comparison of sequences with GenBank database. Results All root dentine samples with patent tubules showed evidence of bacterial cell invasion (TIF value range from 5.7 to 9.0) to depths of 200 mm or more. A spectrum of Gram-positive and Gram-negative cell morphotypes were visualized, and molecular typing identified species of Granulicatella, Streptococcus, Klebsiella, Enterobacter, Acinetobacter, and Pseudomonas as dentinal tubule residents. Conclusion A novel in vivo model is described, which provides for human root dentine to be efficiently infected by oral microorganisms. A range of bacteria were able to initially invade dentinal tubules within exposed dentine. The model will be useful for testing the effectiveness of antiseptics, irrigants, and potential tubule occluding agents in preventing bacterial invasion of dentine. PMID:27119760

  19. In vivo model for microbial invasion of tooth root dentinal tubules.

    PubMed

    Brittan, Jane L; Sprague, Susan V; Macdonald, Emma L; Love, Robert M; Jenkinson, Howard F; West, Nicola X

    2016-04-01

    Objective Bacterial penetration of dentinal tubules via exposed dentine can lead to root caries and promote infections of the pulp and root canal system. The aim of this work was to develop a new experimental model for studying bacterial invasion of dentinal tubules within the human oral cavity. Material and Methods Sections of human root dentine were mounted into lower oral appliances that were worn by four human subjects for 15 d. Roots were then fixed, sectioned, stained and examined microscopically for evidence of bacterial invasion. Levels of invasion were expressed as Tubule Invasion Factor (TIF). DNA was extracted from root samples, subjected to polymerase chain reaction amplification of 16S rRNA genes, and invading bacteria were identified by comparison of sequences with GenBank database. Results All root dentine samples with patent tubules showed evidence of bacterial cell invasion (TIF value range from 5.7 to 9.0) to depths of 200 mm or more. A spectrum of Gram-positive and Gram-negative cell morphotypes were visualized, and molecular typing identified species of Granulicatella, Streptococcus, Klebsiella, Enterobacter, Acinetobacter, and Pseudomonas as dentinal tubule residents. Conclusion A novel in vivo model is described, which provides for human root dentine to be efficiently infected by oral microorganisms. A range of bacteria were able to initially invade dentinal tubules within exposed dentine. The model will be useful for testing the effectiveness of antiseptics, irrigants, and potential tubule occluding agents in preventing bacterial invasion of dentine. PMID:27119760

  20. Microorganism penetration in dentinal tubules of instrumented and retreated root canal walls. In vitro SEM study

    PubMed Central

    Al-Sulaiman, Alaa; Al-Rasheed, Fellwa; Alnajjar, Fatimah; Al-Abdulwahab, Bander; Al-Badah, Abdulhakeem

    2014-01-01

    Objectives This in vitro study aimed to investigate the ability of Candida albicans (C. albicans) and Enterococcus faecalis (E. faecalis) to penetrate dentinal tubules of instrumented and retreated root canal surface of split human teeth. Materials and Methods Sixty intact extracted human single-rooted teeth were divided into 4 groups, negative control, positive control without canal instrumentation, instrumented, and retreated. Root canals in the instrumented group were enlarged with endodontic instruments, while root canals in the retreated group were enlarged, filled, and then removed the canal filling materials. The teeth were split longitudinally after canal preparation in 3 groups except the negative control group. The teeth were inoculated with both microorganisms separately and in combination. Teeth specimens were examined by scanning electron microscopy (SEM), and the depth of penetration into the dentinal tubules was assessed using the SMILE view software (JEOL Ltd). Results Penetration of C. albicans and E. faecalis into the dentinal tubules was observed in all 3 groups, although penetration was partially restricted by dentin debris of tubules in the instrumented group and remnants of canal filling materials in the retreated group. In all 3 groups, E. faecalis penetrated deeper into the dentinal tubules by way of cell division than C. albicans which built colonies and penetrated by means of hyphae. Conclusions Microorganisms can easily penetrate dentinal tubules of root canals with different appearance based on the microorganism size and status of dentinal tubules. PMID:25383343

  1. Regulation of proximal tubule vacuolar H+-ATPase by PKA and AMP-activated protein kinase

    PubMed Central

    Al-bataineh, Mohammad M.; Gong, Fan; Marciszyn, Allison L.; Myerburg, Michael M.

    2014-01-01

    The vacuolar H+-ATPase (V-ATPase) mediates ATP-driven H+ transport across membranes. This pump is present at the apical membrane of kidney proximal tubule cells and intercalated cells. Defects in the V-ATPase and in proximal tubule function can cause renal tubular acidosis. We examined the role of protein kinase A (PKA) and AMP-activated protein kinase (AMPK) in the regulation of the V-ATPase in the proximal tubule as these two kinases coregulate the V-ATPase in the collecting duct. As the proximal tubule V-ATPases have different subunit compositions from other nephron segments, we postulated that V-ATPase regulation in the proximal tubule could differ from other kidney tubule segments. Immunofluorescence labeling of rat ex vivo kidney slices revealed that the V-ATPase was present in the proximal tubule both at the apical pole, colocalizing with the brush-border marker wheat germ agglutinin, and in the cytosol when slices were incubated in buffer alone. When slices were incubated with a cAMP analog and a phosphodiesterase inhibitor, the V-ATPase accumulated at the apical pole of S3 segment cells. These PKA activators also increased V-ATPase apical membrane expression as well as the rate of V-ATPase-dependent extracellular acidification in S3 cell monolayers relative to untreated cells. However, the AMPK activator AICAR decreased PKA-induced V-ATPase apical accumulation in proximal tubules of kidney slices and decreased V-ATPase activity in S3 cell monolayers. Our results suggest that in proximal tubule the V-ATPase subcellular localization and activity are acutely coregulated via PKA downstream of hormonal signals and via AMPK downstream of metabolic stress. PMID:24553431

  2. Male reproductive biology of Aedes mosquitoes.

    PubMed

    Oliva, Clelia F; Damiens, David; Benedict, Mark Q

    2014-04-01

    Among Aedes mosquitoes are species responsible for transmission of serious pathogens to humans. To cope with the current threats to long-term effectiveness of the traditional vector control methods, non-conventional control strategies are being developed. These include autocidal control such as the release of sterile males (sterile insect technique) and the release of Wolbachia-infected males to induce sexual sterility (incompatible insect technique) and pathogen-refractory strain replacement variations using Wolbachia. Sterile male types of techniques particularly depend on released males' ability to successfully mate with wild females. For that reason, a good understanding of male mating biology, including a thorough understanding of the reproductive system and mating capacity, increases the likelihood of success of such genetic vector control programmes. Here we review the literature concerning the reproduction of Aedes mosquitoes with an emphasis on the male biology. We consider sexual maturation, mate finding, insemination, male reproductive capacity, and the occurrence of multiple matings. We also discuss which parameters are of greatest importance for the successful implementation of autocidal control methods and propose questions for future research. PMID:24308996

  3. Release of renal dipeptidase from rabbit renal proximal tubules and its inhibition by gentamicin.

    PubMed

    Kang, B Y; We, J S; Choi, K; Lee, H B; Han, H J; Park, H S

    1999-08-01

    Effects of several drugs on rabbit renal proximal tubules were examined for the applicability of renal dipeptidase (RDPase, EC 3. 4. 13. 11) release as a model system to study nephrotoxicity. The proximal tubule prepared by the method of Taub (1990) released RDPase spontaneously in the control experiment which was confirmed by Western blotting. RDPase was also released from cisplatin, lipopolysaccharide (LPS), and indomethacin-treated tubules. Gentamicin inhibited RDPase release in a concentration-dependent manner. This RDPase release system may not be a general model to screen nephrotoxicity but could be a useful source of RDPase purification in a simple and inexpensive way. PMID:10489875

  4. Aedes aegypti and Aedes albopictus Habitat Preferences in South Texas, USA

    PubMed Central

    Champion, Samantha R; Vitek, Christopher J

    2014-01-01

    The South Texas region has a historical record of occasional dengue outbreaks. The recent introduction of chikungunya virus to the Caribbean suggests that this disease may be a concern as well. Six different cities and three field habitat types (residential, tire shops, and cemeteries) were examined for evidence of habitat and longitudinal preference of two vector species, Aedes aegypti and Aedes albopictus. A. aegypti was more prevalent in tire shop sites, while A. albopictus was more prevalent in cemetery sites. In residential sites, the relative abundance of the two species varied with longitude, with A. albopictus being more abundant near the coast, and A. aegypti being more abundant inland. There was also a temporal variation, with A. aegypti declining in frequency over time in residential sites. These results have implications for control strategies and disease risk and suggest a greater need for increased surveillance and research in the region. PMID:25520559

  5. Aedes aegypti and Aedes albopictus Habitat Preferences in South Texas, USA.

    PubMed

    Champion, Samantha R; Vitek, Christopher J

    2014-01-01

    The South Texas region has a historical record of occasional dengue outbreaks. The recent introduction of chikungunya virus to the Caribbean suggests that this disease may be a concern as well. Six different cities and three field habitat types (residential, tire shops, and cemeteries) were examined for evidence of habitat and longitudinal preference of two vector species, Aedes aegypti and Aedes albopictus. A. aegypti was more prevalent in tire shop sites, while A. albopictus was more prevalent in cemetery sites. In residential sites, the relative abundance of the two species varied with longitude, with A. albopictus being more abundant near the coast, and A. aegypti being more abundant inland. There was also a temporal variation, with A. aegypti declining in frequency over time in residential sites. These results have implications for control strategies and disease risk and suggest a greater need for increased surveillance and research in the region. PMID:25520559

  6. Ultrastructural changes in renal proximal tubules after tetraethyllead intoxication

    SciTech Connect

    Chang, L.W.; Wade, P.R.; Reuhl, K.R.; Olson, M.J.

    1980-10-01

    Tetraethyllead (TEL) has been shown to be both an occupational and an environmental hazard to human health. The present study investigates pathological changes in the kidney as a result of TEL poisoning. Rabbits were injected (ip) with 100 to 200 mg TEL, and controls were injected with an equal volume of normal saline solution. Animals were sacrificed upon onset of toxic symptoms (hyperirritation, tremor, and convulsion). Animals were perfused with 2.5% glutaraldehyde. Tissue samples from the renal cortex were obtained for electron microscopy. Pathological changes were not remarkable at the light microscopic level; however, electron microscopic examination revealed marked cytological changes in the epithelial cells of the proximal tubules (PT) of animals treated with TEL. Enlargement of apical vacuoles and accumulation of lysosomes and microbodies were prominent findings in many PT epithelial cells. Many lysosomes appeared to be atypical in nature, displaying a high degree of pleomorphism in size, shape, and density. Giant lysosomes measuring 8 to 10 ..mu..m in diameter and crystalloid bodies within lysosomes were also observed. Configurational changes (increased convolution, branching, vesiculation, and degranulation) of the rough endoplasmic reticulum leading to the formation of honeycomb-like bodies were also found in many PT epithelial cells. The formation of the honeycomb-like bodies may represent a hyperplastic, hypoactive form of the rough endoplasmic reticulum and denotes a disruption of protein synthesis in these cells by TEL.

  7. A Role for Phospholipase A2 Activity in Membrane Tubule Formation and TGN Trafficking

    PubMed Central

    Schmidt, John A.; Kalkofen, Danielle N.; Donovan, Kirk W.; Brown, William J.

    2015-01-01

    We have investigated the role of phospholipase A2 (PLA2) enzymes in generating membrane tubules at the trans-Golgi network (TGN). Constitutive TGN membrane tubules and those induced by over-expressing kinase dead protein kinase D were inhibited by the PLA2 inhibitors ONO-RS-082 (ONO) and bromoenol lactone. These antagonists also inhibited secretory delivery of both soluble and transmembrane cargoes. Finally, use of the reversible antagonist ONO and time-lapse imaging revealed for the first time that PLA2 antagonists inhibit the initiation of membrane tubule formation at the TGN. Thus, PLA2 enzymes appear to have an important role in the earliest steps of membrane tubule formation at the TGN, which are utilized for membrane trafficking. PMID:20874826

  8. The Directional Observation of Highly Dynamic Membrane Tubule Formation Induced by Engulfed Liposomes

    PubMed Central

    Zhang, Xiaoming; Dai, Luru; Wang, Anhe; Wölk, Christian; Dobner, Bodo; Brezesinski, Gerald; Tang, Yunqing; Wang, Xianyou; Li, Junbai

    2015-01-01

    Highly dynamic tubular structures in cells are responsible for exchanges between organelles. Compared with bacterial invasion, the most affordable and least toxic lipids were found in this study to be gentle and safe exogenous stimuli for the triggering of membrane tubules. A specific lipid system was internalized by NIH3T3 cells. Following cellular uptake, the constructed liposomes traveled towards the nucleus in aggregations and were gradually distributed into moving vesicles and tubules in the cytosol. The triggered tubules proceeded, retreated or fluctuated along the cytoskeleton and were highly dynamic, moving quickly (up to several microns per second), and breaking and fusing frequently. These elongated tubules could also fuse with one another, giving rise to polygonal membrane networks. These lipid systems, with the novel property of accelerating intracellular transport, provide a new paradigm for investigating cellular dynamics. PMID:26548331

  9. Length Is Associated with Pain: Jellyfish with Painful Sting Have Longer Nematocyst Tubules than Harmless Jellyfish.

    PubMed

    Kitatani, Ryuju; Yamada, Mayu; Kamio, Michiya; Nagai, Hiroshi

    2015-01-01

    A large number of humans are stung by jellyfish all over the world. The stings cause acute pain followed by persistent pain and local inflammation. Harmful jellyfish species typically cause strong pain, whereas harmless jellyfish cause subtle or no pain. Jellyfish sting humans by injecting a tubule, contained in the nematocyst, the stinging organ of jellyfish. The tubule penetrates into the skin leading to venom injection. The detailed morphology of the nematocyst tubule and molecular structure of the venom in the nematocyst has been reported; however, the mechanism responsible for the difference in pain that is caused by harmful and harmless jellyfish sting has not yet been explored or explained. Therefore, we hypothesized that differences in the length of the nematocyst tubule leads to different degrees of epithelial damage. The initial acute pain might be generated by penetration of the tubule, which stimulates pain receptor neurons, whilst persistent pain might be caused by injection of venom into the epithelium. To test this hypothesis we compared the lengths of discharged nematocyst tubules from harmful and harmless jellyfish species and evaluated their ability to penetrate human skin. The results showed that the harmful jellyfish species, Chrysaora pacifica, Carybdea brevipedalia, and Chironex yamaguchii, causing moderate to severe pain, have nematocyst tubules longer than 200 μm, compared with a jellyfish species that cause little or no pain, Aurelia aurita. The majority of the tubules of harmful jellyfishes, C. yamaguchii and C. brevipedalia, were sufficiently long to penetrate the human epidermis and physically stimulate the free nerve endings of Aδ pain receptor fibers around plexuses to cause acute pain and inject the venom into the human skin epithelium to cause persistent pain and inflammation. PMID:26309256

  10. Length Is Associated with Pain: Jellyfish with Painful Sting Have Longer Nematocyst Tubules than Harmless Jellyfish

    PubMed Central

    Kitatani, Ryuju; Yamada, Mayu; Kamio, Michiya; Nagai, Hiroshi

    2015-01-01

    A large number of humans are stung by jellyfish all over the world. The stings cause acute pain followed by persistent pain and local inflammation. Harmful jellyfish species typically cause strong pain, whereas harmless jellyfish cause subtle or no pain. Jellyfish sting humans by injecting a tubule, contained in the nematocyst, the stinging organ of jellyfish. The tubule penetrates into the skin leading to venom injection. The detailed morphology of the nematocyst tubule and molecular structure of the venom in the nematocyst has been reported; however, the mechanism responsible for the difference in pain that is caused by harmful and harmless jellyfish sting has not yet been explored or explained. Therefore, we hypothesized that differences in the length of the nematocyst tubule leads to different degrees of epithelial damage. The initial acute pain might be generated by penetration of the tubule, which stimulates pain receptor neurons, whilst persistent pain might be caused by injection of venom into the epithelium. To test this hypothesis we compared the lengths of discharged nematocyst tubules from harmful and harmless jellyfish species and evaluated their ability to penetrate human skin. The results showed that the harmful jellyfish species, Chrysaora pacifica, Carybdea brevipedalia, and Chironex yamaguchii, causing moderate to severe pain, have nematocyst tubules longer than 200 μm, compared with a jellyfish species that cause little or no pain, Aurelia aurita. The majority of the tubules of harmful jellyfishes, C. yamaguchii and C. brevipedalia, were sufficiently long to penetrate the human epidermis and physically stimulate the free nerve endings of Aδ pain receptor fibers around plexuses to cause acute pain and inject the venom into the human skin epithelium to cause persistent pain and inflammation. PMID:26309256

  11. Automatic glandular and tubule region segmentation in histological grading of breast cancer

    NASA Astrophysics Data System (ADS)

    Nguyen, Kien; Barnes, Michael; Srinivas, Chukka; Chefd'hotel, Christophe

    2015-03-01

    In the popular Nottingham histologic score system for breast cancer grading, the pathologist analyzes the H and E tissue slides and assigns a score, in the range of 1-3, for tubule formation, nuclear pleomorphism and mitotic activity in the tumor regions. The scores from these three factors are added to give a final score, ranging from 3-9 to grade the cancer. Tubule score (TS), which reflects tubular formation, is a value in 1-3 given by manually estimating the percentage of glandular regions in the tumor that form tubules. In this paper, given an H and E tissue image representing a tumor region, we propose an automated algorithm to detect glandular regions and detect the presence of tubules in these regions. The algorithm first detects all nuclei and lumen candidates in the input image, followed by identifying tumor nuclei from the detected nuclei and identifying true lumina from the lumen candidates using a random forest classifier. Finally, it forms the glandular regions by grouping the closely located tumor nuclei and lumina using a graph-cut-based method. The glandular regions containing true lumina are considered as the ones that form tubules (tubule regions). To evaluate the proposed method, we calculate the tubule percentage (TP), i.e., the ratio of the tubule area to the total glandular area for 353 H and E images of the three TSs, and plot the distribution of these TP values. This plot shows the clear separation among these three scores, suggesting that the proposed algorithm is useful in distinguishing images of these TSs.

  12. Instantaneous adhesion of Cuvierian tubules in the sea cucumber Holothuria forskali.

    PubMed

    Demeuldre, Mélanie; Chinh Ngo, Thi; Hennebert, Elise; Wattiez, Ruddy; Leclère, Philippe; Flammang, Patrick

    2014-06-01

    The peculiar Cuvierian tubules of sea cucumbers function as a defense mechanism. They thwart attacks by creating a sticky network composed of elongated tubules within which the potential predator is entangled in a matter of seconds and thus immobilized. Cuvierian tubules are typical instantaneous adhesive organs in which tissue integrity is destroyed during the release of the adhesive secretion. However, very little information is available about this adhesion process. The adhesive epithelium-the mesothelium-and the sticky material it produces were studied in the species Holothuria forskali using different microscopy techniques (light microscopy, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy). The mesothelium consists of two cell types-peritoneocytes and granular cells-organized in superimposed layers. In tubules before expulsion, peritoneocytes form an outer protective cell layer preventing adhesion when not needed. After expulsion, the elongation process removes this protective layer and allows granular cells to unfold and to become exposed at the tubule surface. At this stage, Cuvierian tubules are still not sticky. Upon contact with a surface, however, granular cells release their granule contents. Once released, this material changes in aspect, swells, and spreads readily on any type of substrate where it forms a thin homogeneous layer. After tubule peeling, this layer remains on the surface but is often contaminated with collagen fibers. Atomic force microscopy demonstrated the adhesive layer to be made up of globular nanostructures measuring about 70 nm in diameter and to be more adhesive than the collagen fibers left on it. The morphological organization of Cuvierian tubules therefore allows contact-dependent deposition of an adhesive material presenting a high affinity for various surfaces. It is certainly an adaptive advantage for a defense organ to be able to entangle different types of predators. PMID

  13. Gβ1γ2 activates phospholipase A2-dependent Golgi membrane tubule formation

    PubMed Central

    Bechler, Marie E.; Brown, William J.

    2014-01-01

    Heterotrimeric G proteins transduce the ligand binding of transmembrane G protein coupled receptors into a variety of intracellular signaling pathways. Recently, heterotrimeric Gβγ subunit signaling at the Golgi complex has been shown to regulate the formation of vesicular transport carriers that deliver cargo from the Golgi to the plasma membrane. In addition to vesicles, membrane tubules have also been shown to mediate export from the Golgi complex, which requires the activity of cytoplasmic phospholipase A2 (PLA2) enzyme activity. Through the use of an in vitro reconstitution assay with isolated Golgi complexes, we provide evidence that Gβ1γ2 signaling also stimulates Golgi membrane tubule formation. In addition, we show that an inhibitor of Gβγ activation of PLA2 enzymes inhibits in vitro Golgi membrane tubule formation. Additionally, purified Gβγ protein stimulates membrane tubules in the presence of low (sub-threshold) cytosol concentrations. Importantly, this Gβγ stimulation of Golgi membrane tubule formation was inhibited by treatment with the PLA2 antagonist ONO-RS-082. These studies indicate that Gβ1γ2 signaling activates PLA2 enzymes required for Golgi membrane tubule formation, thus establishing a new layer of regulation for this process. PMID:25019068

  14. Membrane tubule formation by banana-shaped proteins with or without transient network structure.

    PubMed

    Noguchi, Hiroshi

    2016-01-01

    In living cells, membrane morphology is regulated by various proteins. Many membrane reshaping proteins contain a Bin/Amphiphysin/Rvs (BAR) domain, which consists of a banana-shaped rod. The BAR domain bends the biomembrane along the rod axis and the features of this anisotropic bending have recently been studied. Here, we report on the role of the BAR protein rods in inducing membrane tubulation, using large-scale coarse-grained simulations. We reveal that a small spontaneous side curvature perpendicular to the rod can drastically alter the tubulation dynamics at high protein density, whereas no significant difference is obtained at low density. A percolated network is intermediately formed depending on the side curvature. This network suppresses tubule protrusion, leading to the slow formation of fewer tubules. Thus, the side curvature, which is generated by protein-protein and membrane-protein interactions, plays a significant role in tubulation dynamics. We also find that positive surface tensions and the vesicle membrane curvature can stabilize this network structure by suppressing the tubulation. PMID:26863901

  15. Membrane tubule formation by banana-shaped proteins with or without transient network structure

    NASA Astrophysics Data System (ADS)

    Noguchi, Hiroshi

    2016-02-01

    In living cells, membrane morphology is regulated by various proteins. Many membrane reshaping proteins contain a Bin/Amphiphysin/Rvs (BAR) domain, which consists of a banana-shaped rod. The BAR domain bends the biomembrane along the rod axis and the features of this anisotropic bending have recently been studied. Here, we report on the role of the BAR protein rods in inducing membrane tubulation, using large-scale coarse-grained simulations. We reveal that a small spontaneous side curvature perpendicular to the rod can drastically alter the tubulation dynamics at high protein density, whereas no significant difference is obtained at low density. A percolated network is intermediately formed depending on the side curvature. This network suppresses tubule protrusion, leading to the slow formation of fewer tubules. Thus, the side curvature, which is generated by protein-protein and membrane-protein interactions, plays a significant role in tubulation dynamics. We also find that positive surface tensions and the vesicle membrane curvature can stabilize this network structure by suppressing the tubulation.

  16. mTORC2 regulates renal tubule sodium uptake by promoting ENaC activity.

    PubMed

    Gleason, Catherine E; Frindt, Gustavo; Cheng, Chih-Jen; Ng, Michael; Kidwai, Atif; Rashmi, Priyanka; Lang, Florian; Baum, Michel; Palmer, Lawrence G; Pearce, David

    2015-01-01

    The epithelial Na+ channel (ENaC) is essential for Na+ homeostasis, and dysregulation of this channel underlies many forms of hypertension. Recent studies suggest that mTOR regulates phosphorylation and activation of serum/glucocorticoid regulated kinase 1 (SGK1), which is known to inhibit ENaC internalization and degradation; however, it is not clear whether mTOR contributes to the regulation of renal tubule ion transport. Here, we evaluated the effect of selective mTOR inhibitors on kidney tubule Na+ and K+ transport in WT and Sgk1-/- mice, as well as in isolated collecting tubules. We found that 2 structurally distinct competitive inhibitors (PP242 and AZD8055), both of which prevent all mTOR-dependent phosphorylation, including that of SGK1, caused substantial natriuresis, but not kaliuresis, in WT mice, which indicates that mTOR preferentially influences ENaC function. PP242 also substantially inhibited Na+ currents in isolated perfused cortical collecting tubules. Accordingly, patch clamp studies on cortical tubule apical membranes revealed that mTOR inhibition markedly reduces ENaC activity, but does not alter activity of K+ inwardly rectifying channels (ROMK channels). Together, these results demonstrate that mTOR regulates kidney tubule ion handling and suggest that mTOR regulates Na+ homeostasis through SGK1-dependent modulation of ENaC activity. PMID:25415435

  17. PI3Ks Maintain the Structural Integrity of T-Tubules in Cardiac Myocytes

    PubMed Central

    Wu, Chia-Yen C.; Jia, Zhiheng; Wang, Wei; Ballou, Lisa M.; Jiang, Ya-Ping; Chen, Biyi; Mathias, Richard T.; Cohen, Ira S.; Song, Long-Sheng; Entcheva, Emilia; Lin, Richard Z.

    2011-01-01

    Background Phosphoinositide 3-kinases (PI3Ks) regulate numerous physiological processes including some aspects of cardiac function. Although regulation of cardiac contraction by individual PI3K isoforms has been studied, little is known about the cardiac consequences of downregulating multiple PI3Ks concurrently. Methods and Results Genetic ablation of both p110α and p110β in cardiac myocytes throughout development or in adult mice caused heart failure and death. Ventricular myocytes from double knockout animals showed transverse tubule (T-tubule) loss and disorganization, misalignment of L-type Ca2+ channels in the T-tubules with ryanodine receptors in the sarcoplasmic reticulum, and reduced Ca2+ transients and contractility. Junctophilin-2, which is thought to tether T-tubules to the sarcoplasmic reticulum, was mislocalized in the double PI3K-null myocytes without a change in expression level. Conclusions PI3K p110α and p110β are required to maintain the organized network of T-tubules that is vital for efficient Ca2+-induced Ca2+ release and ventricular contraction. PI3Ks maintain T-tubule organization by regulating junctophilin-2 localization. These results could have important medical implications because several PI3K inhibitors that target both isoforms are being used to treat cancer patients in clinical trials. PMID:21912691

  18. Membrane tubule formation by banana-shaped proteins with or without transient network structure

    PubMed Central

    Noguchi, Hiroshi

    2016-01-01

    In living cells, membrane morphology is regulated by various proteins. Many membrane reshaping proteins contain a Bin/Amphiphysin/Rvs (BAR) domain, which consists of a banana-shaped rod. The BAR domain bends the biomembrane along the rod axis and the features of this anisotropic bending have recently been studied. Here, we report on the role of the BAR protein rods in inducing membrane tubulation, using large-scale coarse-grained simulations. We reveal that a small spontaneous side curvature perpendicular to the rod can drastically alter the tubulation dynamics at high protein density, whereas no significant difference is obtained at low density. A percolated network is intermediately formed depending on the side curvature. This network suppresses tubule protrusion, leading to the slow formation of fewer tubules. Thus, the side curvature, which is generated by protein–protein and membrane–protein interactions, plays a significant role in tubulation dynamics. We also find that positive surface tensions and the vesicle membrane curvature can stabilize this network structure by suppressing the tubulation. PMID:26863901

  19. Eps 15 Homology Domain (EHD)-1 Remodels Transverse Tubules in Skeletal Muscle

    PubMed Central

    Demonbreun, Alexis R.; Swanson, Kaitlin E.; Rossi, Ann E.; Deveaux, H. Kieran; Earley, Judy U.; Allen, Madison V.; Arya, Priyanka; Bhattacharyya, Sohinee; Band, Hamid; Pytel, Peter; McNally, Elizabeth M.

    2015-01-01

    We previously showed that Eps15 homology domain-containing 1 (EHD1) interacts with ferlin proteins to regulate endocytic recycling. Myoblasts from Ehd1-null mice were found to have defective recycling, myoblast fusion, and consequently smaller muscles. When expressed in C2C12 cells, an ATPase dead-EHD1 was found to interfere with BIN1/amphiphysin 2. We now extended those findings by examining Ehd1-heterozygous mice since these mice survive to maturity in normal Mendelian numbers and provide a ready source of mature muscle. We found that heterozygosity of EHD1 was sufficient to produce ectopic and excessive T-tubules, including large intracellular aggregates that contained BIN1. The disorganized T-tubule structures in Ehd1-heterozygous muscle were accompanied by marked elevation of the T-tubule-associated protein DHPR and reduction of the triad linker protein junctophilin 2, reflecting defective triads. Consistent with this, Ehd1-heterozygous muscle had reduced force production. Introduction of ATPase dead-EHD1 into mature muscle fibers was sufficient to induce ectopic T-tubule formation, seen as large BIN1 positive structures throughout the muscle. Ehd1-heterozygous mice were found to have strikingly elevated serum creatine kinase and smaller myofibers, but did not display findings of muscular dystrophy. These data indicate that EHD1 regulates the maintenance of T-tubules through its interaction with BIN1 and links T-tubules defects with elevated creatine kinase and myopathy. PMID:26325203

  20. Evidence for role of cytosolic free calcium in hypoxia-induced proximal tubule injury.

    PubMed Central

    Kribben, A; Wieder, E D; Wetzels, J F; Yu, L; Gengaro, P E; Burke, T J; Schrier, R W

    1994-01-01

    The role of cytosolic free Ca2+ ([Ca2+]i) in hypoxic injury was investigated in rat proximal tubules. [Ca2+]i was measured using fura-2 and cell injury was estimated with propidium iodide (PI) in individual tubules using video imaging fluorescence microscopy. [Ca2+]i increased from approximately 170 to approximately 390 nM during 5 min of hypoxia. This increase preceded detectable cell injury as assessed by PI and was reversible with reoxygenation. 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA; 100 microM) reduced [Ca2+]i under basal conditions (approximately 80 nM) and during hypoxia (approximately 120 nM) and significantly attenuated hypoxic injury. When [Ca2+]i and hypoxic cell injury were studied concurrently in the same individual tubules, the 10 min [Ca2+]i rise correlated significantly with subsequent cell damage observed at 20 min. 2 mM glycine did not block the rise in [Ca2+]i, yet protected the tubules from hypoxic injury. These results indicate that in rat proximal tubules, hypoxia induces an increase of [Ca2+]i which occurs before cell damage. The protective effect of BAPTA supports a role for [Ca2+]i in the initiation of hypoxic proximal tubule injury. The glycine results, however, implicate calcium-independent mechanisms of injury and/or blockade of calcium-mediated processes of injury such as activation of phospholipases or proteases. Images PMID:8182125

  1. FISH landmarks for Aedes aegypti chromosomes.

    PubMed

    Brown, S E; Knudson, D L

    1997-05-01

    Aedes aegypti metaphase chromosome landmarks have been developed so that each chromosome of the haploid genome can be unambiguously identified and oriented by fluorescence in situ hybridization (FISH) and digital imaging microscopy. The FISH tags were derived from three cosmids that contain repetitive Ae. aegypti sequences and their unique FISH tagging characteristics are demonstrated. The sequence of the three chromosomal tags revealed that the chromosome 1 tag is an 18S fragment from the ribosomal cistron, and the other two chromosomal tags are repeats found in Ae. aegypti with no apparent similarity to known sequences. A single plasmid that contains the three chromosomes tag sequences has been constructed to simplify future FISH physical mapping. PMID:9099584

  2. The Aedes aegypti genome: a comparative perspective.

    PubMed

    Waterhouse, R M; Wyder, S; Zdobnov, E M

    2008-02-01

    The sequencing of the second mosquito genome, Aedes aegypti, in addition to Anopheles gambiae, is a major milestone that will drive molecular-level and genome-wide high-throughput studies of not only these but also other mosquito vectors of human pathogens. Here we overview the ancestry of the mosquito genes, list the major expansions of gene families that may relate to species adaptation processes, as exemplified by CYP9 cytochrome P450 genes, and discuss the conservation of chromosomal gene arrangements among the two mosquitoes and fruit fly. Many more invertebrate genomes are expected to be sequenced in the near future, including additional vectors of human pathogens (see http://www.vectorbase.org), and further comparative analyses will become increasingly refined and informative, hopefully improving our understanding of the genetic basis of phenotypical differences among these species, their vectorial capacity, and ultimately leading to the development of novel disease control strategies. PMID:18237279

  3. History of Aedes mosquitoes in Hawaii.

    PubMed

    Winchester, Jonathan C; Kapan, Durrell D

    2013-06-01

    As a geographically isolated island chain with no native mosquitoes, Hawaii is a model for examining the mechanisms behind insect vector invasions and their subsequent interactions with each other and with human populations. The yellow fever mosquito, Aedes aegypti, and the Asian tiger mosquito, Ae. albopictus, have been responsible for epidemics of dengue in Hawaii. As one of the world's earliest locations to be invaded by both species, Hawaii's history is particularly relevant because both species are currently invading new areas worldwide and are implicated in outbreaks of emergent or reemergent pathogens such as dengue, chikungunya, and yellow fever. Here we analyze the historical records of mosquito introductions in order to understand the factors that have led to the current distribution of these 2 mosquitoes in the Hawaiian Islands. PMID:23923330

  4. Spatial Stability of Adult Aedes aegypti Populations

    PubMed Central

    Barrera, Roberto

    2011-01-01

    Vector control programs could be more efficient by identifying the location of highly productive sites of Aedes aegypti. This study explored if the number of female adults of Ae. aegypti in BG-Sentinel traps was clustered and if their spatial distribution changed in time in two neighborhoods in San Juan, Puerto Rico. Traps were uniformly distributed across each neighborhood (130 m from each other), and samples were taken every 3 weeks. Global and local spatial autocorrelations were explored. Spatial stability existed if the rank order of trap captures was kept in time. There was lack of global autocorrelation in both neighborhoods, precluding their stratification for control purposes. Hot and cold spots were identified, revealing the highly focal nature of Ae. aegypti. There was significant spatial stability throughout the study in both locations. The consistency in trap productivity in time could be used to increase the effectiveness of vector and dengue control programs. PMID:22144449

  5. Treatment of dentinal tubules by Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Chmelíčkova, Hana; Zapletalova, Zdeňka; Peřina, Jan, Jr.; Novotný, Radko; Kubínek, Roman; Stranyánek, Martin

    2005-08-01

    Symptom of cervical dentine hypersensitivity attacks from 10% to 15% of population and causes an uncomfortable pain during contact with any matter. Sealing of open dentinal tubules is one of the methods to reach insensibility. Laser as a source of coherent radiation is used to melt dentine surface layers. Melted dentine turns to hard mass with a smooth, non-porous surface. Simulation of this therapy was made in vitro by means of LASAG Nd:YAG pulsed laser system KLS 246-102. Eighty human extracted teeth were cut horizontally to obtain samples from 2 mm to 3 mm thick. First experiments were done on cross section surfaces to find an optimal range of laser parameters. A wide range of energies from 30 mJ to 210 mJ embedded in 0,3 ms long pulse was tested. Motion in X and Y axes was ensured by a CNC driven table and the pulse frequency 15 Hz was chosen to have a suitable overlap of laser spots. Some color agents were examined with the aim to improve surface absorption. Scanning Electron Microscopy was used to evaluate all samples and provided optimal values of energies around 50 J.cm-2. Next experiments were done with the beam oriented perpendicularly to a root surface, close to the real situation. Optical fibers with the diameter of 0,6 mm and 0,2 mm were used to guide a laser beam to teeth surfaces. Laser processing heads with lens F = 100 mm and F = 50 mm were used. The best samples were investigated by means of the Atomic Force Microscopy.

  6. Area-wide management of Aedes albopictus: gauging the efficacy of multiple control measures during 2010.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aedes albopictus is a major human biting pest and is considered second only to Aedes aegypti in its importance as a disease vector of dengue. Aedes albopictus is responsible for the majority of service requests from urban and suburban residents in New Jersey during recent years; however, standard a...

  7. Fluid Secretion in Isolated Proximal Straight Renal Tubules EFFECT OF HUMAN UREMIC SERUM

    PubMed Central

    Grantham, Jared J.; Irwin, Richard L.; Qualizza, Patti B.; Tucker, Donald R.; Whittier, Frederick C.

    1973-01-01

    We have examined the effect of normal and uremic human sera on the transtubular flow of fluid in isolated perfused segments of rabbit proximal convoluted and straight renal tubules. Proximal convoluted and straight tubules absorbed fluid from the lumen when the external bath was normal rabbit serum. Normal human sera in the bath depressed net fluid absorption in both tubular segments, but more importantly, uremic human serum caused proximal straight tubules to secrete fluid into the lumen. Fluid secretion was also demonstrated indirectly by observing in nonperfused proximal straight, but not proximal convoluted tubules, that the normally collapsed lumens opened widely in uremic serum. Nonperfused proximal straight tubules developed expanded lumens even after a 25-fold dilution of human uremic serum with normal rabbit serum, whereas lumen expansion occurred only in undiluted normal human serum, on the average. Serum from acutely uremic rabbits possessed secretory activity but normal rabbit serum did not. The secretory effect of uremic sera in proximal straight tubules was inhibited by cooling and ouabain and probenecid. The secretory activity of uremic sera was removed by dialysis, but not by freezing or boiling. Para-aminohippurate and benzoate caused fluid secretion in proximal straight tubules but urea, creatinine, guanidinosuccinate, and urate did not. On the basis of these results, we suggest that the secretory factor in serum may be a substance or group of substances possibly related to the hippurate class of organic molecules that are accumulated to relatively high concentrations in renal failure. The secretory material in the serum of uremic patients may significantly influence the transport of salt and water in relatively intact residual nephrons. Images PMID:4738063

  8. Near tubule and intertubular bovine detin mapped at the 250 nm level.

    SciTech Connect

    Stock, S.R.; Veis, A.; Telser, A.; Cai, Z.

    2011-11-01

    In this study, simultaneous diffraction and fluorescence mapping with a (250 nm){sup 2}, 10.1 keV synchrotron X-ray beam investigated the spatial distribution of carbonated apatite (cAp) mineral and elemental Ca (and other cations including Zn) around dentin tubules. In 1 {mu}m thick sections of near-pulp root dentin, where peritubular dentin (PTD) is newly forming, high concentrations of Zn, relative to those in intertubular dentin (ITD), were observed adjacent to and surrounding the tubule lumens. Some but not all tubules exhibited hypercalcified collars (high Ca signal relative to the surrounding ITD), and, when present, the zone of high Ca did not extend around the tubule. Diffraction rings from cAp 00.2 and 11.2 + 21.1 + 30.0 reflections were observed, and cAp was the only crystal phase detected. Profiles of Ca, Zn and cAp diffracted intensities showed the same transitions from solid to tubule lumen, indicating the same cAp content and organization in ITD far from the tubules and adjacent to them. Further, the matching Ca and diffraction profiles demonstrated that all of the Ca is in cAp or that any noncrystalline Ca was uniformly distributed throughout the dentin. Variation of 00.2 and 11.2 + 21.1 + 30.0 diffracted intensity was consistent with the expected biaxial crystallographic texture. Extension of X-ray mapping from near 1 {mu}m resolution to the 250 nm level, performed here for dentin and its tubules, will provide new understanding of other mineralized tissues.

  9. ImageJ analysis of dentin tubule distribution in human teeth.

    PubMed

    Williams, Casia; Wu, Yiching; Bowers, Doria F

    2015-08-01

    Mapping the distribution of dentin tubules is vital to understanding the structure-function relationship of dentin, an important indicator of tooth stability. This study compared the distances between and density of tubules in the external dentin located in the crown region of an adult human incisor and molar to determine if analysis could be conducted using light-level microscopy. Teeth were processed for routine histology, cut in cross-section, images captured using Advanced SPOT Program, and microstructure was analyzed using ImageJ (NIH). Intratubular (peritubular) dentin with or without odontoblast processes were observed and although incisor and molar images appeared visually similar, plot profile graphs differed. Distance-intervals between tubules in the incisor (5.45-7.67 μm) had an overall range of 2.22 μm and in the molar (7.43-8.42 μm) an overall range of 0.99 μm. While molar tubule distribution displayed a tighter overall range, there was a smaller distance between most incisor tubules. The average densities observed in incisors were 15,500 tubules/mm(2), compared with 20,100 tubules/mm(2) in molars. ImageJ analysis of prepared histology microscopic slides provides researchers with a rapid, inexpensive assessment tool when compared with advanced/ultrastructural methodologies. By combining routine histological processing and light microscopic observations followed by ImageJ analysis, tooth structure can be converted into numerical data and easily mastered by laboratory personnel. PMID:26150311

  10. Near tubule and intertubular bovine dentin mapped at the 250 nm level

    PubMed Central

    Stock, S. R.; Veis, A.; Telser, A.; Cai, Z.

    2011-01-01

    In this study, simultaneous diffraction and fluorescence mapping with a (250 nm)2, 10.1 keV synchrotron x-ray beam investigated the spatial distribution of carbonated apatite (cAp) mineral and elemental Ca (and other cations including Zn) around dentin tubules. In 1 μm thick sections of near-pulp root dentin, where peritubular dentin (PTD) is newly forming, high concentrations of Zn, relative to those in intertubular dentin (ITD), were observed adjacent to and surrounding the tubule lumens. Some but not all tubules exhibited hypercalcified collars (high Ca signal relative to the surrounding ITD), and, when present, the zone of high Ca did not extend around the tubule. Diffraction rings from cAp 00.2 and 11.2+21.1+30.0 reflections were observed, and cAp was the only crystal phase detected. Profiles of Ca, Zn and cAp diffracted intensities showed the same transitions from solid to tubule lumen, indicating the same cAp content and organization in ITD far from the tubules and adjacent to them. Further, the matching Ca and diffraction profiles demonstrated that all of the Ca is in cAp or that any noncrystalline Ca was uniformly distributed throughout the dentin. Variation of 00.2 and 11.2+21.1+30.0 diffracted intensity was consistent with the expected biaxial crystallographic texture. Extension of x-ray mapping from near 1 μm resolution to the 250 nm level, performed here for dentin and its tubules, will provide new understanding of other mineralized tissues. PMID:21821132

  11. Field evaluation of three botanical repellents against Psorophora ferox, Aedes atlanticus, and Aedes mitchellae.

    PubMed

    Qualls, Whitney A; Xue, Rui-De

    2009-09-01

    Three botanical natural repellents, Swamp Buddy Bug Chaser (AI 12% plant-based essential oils), All Sport (AI plant-based essential oils, benzophenone-3, octinoxate, and octisalate), and Geraniol (AI 25% geraniol oil and lemongrass extract) were evaluated at a field site in Elkton, Florida, to determine the protection time provided against Psorophora ferox, Aedes atlanticus, and Ae. mitchellae. These three products provided different protection times against biting mosquitoes. Geraniol provided the longest protection time from mosquito bites (4 h), followed by All Sport (1.5 h) and Swamp Buddy Bug Chaser (1 h). This study provides the first information about botanical insect repellents against these floodwater mosquito species. PMID:19852232

  12. Modelling adult Aedes aegypti and Aedes albopictus survival at different temperatures in laboratory and field settings

    PubMed Central

    2013-01-01

    Background The survival of adult female Aedes mosquitoes is a critical component of their ability to transmit pathogens such as dengue viruses. One of the principal determinants of Aedes survival is temperature, which has been associated with seasonal changes in Aedes populations and limits their geographical distribution. The effects of temperature and other sources of mortality have been studied in the field, often via mark-release-recapture experiments, and under controlled conditions in the laboratory. Survival results differ and reconciling predictions between the two settings has been hindered by variable measurements from different experimental protocols, lack of precision in measuring survival of free-ranging mosquitoes, and uncertainty about the role of age-dependent mortality in the field. Methods Here we apply generalised additive models to data from 351 published adult Ae. aegypti and Ae. albopictus survival experiments in the laboratory to create survival models for each species across their range of viable temperatures. These models are then adjusted to estimate survival at different temperatures in the field using data from 59 Ae. aegypti and Ae. albopictus field survivorship experiments. The uncertainty at each stage of the modelling process is propagated through to provide confidence intervals around our predictions. Results Our results indicate that adult Ae. albopictus has higher survival than Ae. aegypti in the laboratory and field, however, Ae. aegypti can tolerate a wider range of temperatures. A full breakdown of survival by age and temperature is given for both species. The differences between laboratory and field models also give insight into the relative contributions to mortality from temperature, other environmental factors, and senescence and over what ranges these factors can be important. Conclusions Our results support the importance of producing site-specific mosquito survival estimates. By including fluctuating temperature regimes

  13. Real-time PCR Tests in Dutch Exotic Mosquito Surveys; Implementation of Aedes aegypti and Aedes albopictus Identification Tests, and the Development of Tests for the Identification of Aedes atropalpus and Aedes japonicus japonicus (Diptera: Culicidae).

    PubMed

    van de Vossenberg, B T L H; Ibáñez-Justicia, A; Metz-Verschure, E; van Veen, E J; Bruil-Dieters, M L; Scholte, E J

    2015-05-01

    Since 2009, The Netherlands Food and Consumer Product Safety Authority carries out surveys focusing on, amongst others, the presence of invasive mosquito species (IMS). Special attention is given to exotic container-breeding Aedes species Aedes aegypti (L.), Aedes albopictus (Skuse), Aedes atropalpus (Coquillett), and Aedes japonicus japonicus (Theobald). This study describes the implementation of real-time PCR tests described by Hill et al. (2008) for the identification of Ae. aegypti and Ae. albopictus, and the development of two novel real-time PCR tests for the identification of Ae. atropalpus and Ae. j. japonicus. Initial test showed that optimization of elements of the Ae. aegypti and Ae. albopictus tests was needed. Method validation tests were performed to determine if the implemented and newly developed tests are fit for routine diagnostics. Performance criteria of analytical sensitivity, analytical specificity, selectivity, repeatability, and reproducibility were determined. In addition, experiments were performed to determine the influence of environmental conditions on the usability of DNA extracted from mosquito specimens trapped in BG-Sentinel traps. The real-time PCR tests were demonstrated to be sensitive, specific, repeatable, reproducible, and are less prone to false negative results compared to partial cytochrome c oxidase I gene sequencing owing to the DNA fragmentation caused by environmental influences. PMID:26334807

  14. Isolation and characterization of distinct domains of sarcolemma and T-tubules from rat skeletal muscle.

    PubMed Central

    Muñoz, P; Rosemblatt, M; Testar, X; Palacín, M; Zorzano, A

    1995-01-01

    1. Several cell-surface domains of sarcolemma and T-tubule from skeletal-muscle fibre were isolated and characterized. 2. A protocol of subcellular fractionation was set up that involved the sequential low- and high-speed homogenization of rat skeletal muscle followed by KCl washing, Ca2+ loading and sucrose-density-gradient centrifugation. This protocol led to the separation of cell-surface membranes from membranes enriched in sarcoplasmic reticulum and intracellular GLUT4-containing vesicles. 3. Agglutination of cell-surface membranes using wheat-germ agglutinin allowed the isolation of three distinct cell-surface membrane domains: sarcolemmal fraction 1 (SM1), sarcolemmal fraction 2 (SM2) and a T-tubule fraction enriched in protein tt28 and the alpha 2-component of dihydropyridine receptor. 4. Fractions SM1 and SM2 represented distinct sarcolemmal subcompartments based on different compositions of biochemical markers: SM2 was characterized by high levels of beta 1-integrin and dystrophin, and SM1 was enriched in beta 1-integrin but lacked dystrophin. 5. The caveolae-associated molecule caveolin was very abundant in SM1, SM2 and T-tubules, suggesting the presence of caveolae or caveolin-rich domains in these cell-surface membrane domains. In contrast, clathrin heavy chain was abundant in SM1 and T-tubules, but only trace levels were detected in SM2. 6. Immunoadsorption of T-tubule vesicles with antibodies against protein tt28 and against GLUT4 revealed the presence of GLUT4 in T-tubules under basal conditions and it also allowed the identification of two distinct pools of T-tubules showing different contents of tt28 and dihydropyridine receptors. 7. Our data on distribution of clathrin and dystrophin reveal the existence of subcompartments in sarcolemma from muscle fibre, featuring selective mutually exclusive components. T-tubules contain caveolin and clathrin suggesting that they contain caveolin- and clathrin-rich domains. Furthermore, evidence for the

  15. Identification of distinct steps during tubule formation by the movement protein of Cowpea mosaic virus.

    PubMed

    Pouwels, Jeroen; Kornet, Noortje; van Bers, Nikkie; Guighelaar, Teun; van Lent, Jan; Bisseling, Ton; Wellink, Joan

    2003-12-01

    The movement protein (MP) of Cowpea mosaic virus (CPMV) forms tubules through plasmodesmata in infected plants thus enabling virus particles to move from cell to cell. Localization studies of mutant MPs fused to GFP in protoplasts and plants identified several functional domains within the MP that are involved in distinct steps during tubule formation. Coinoculation experiments and the observation that one of the C-terminal deletion mutants accumulated uniformly in the plasma membrane suggest that dimeric or multimeric MP is first targeted to the plasma membrane. At the plasma membrane the MP quickly accumulates in peripheral punctuate spots, from which tubule formation is initiated. One of the mutant MPs formed tubules containing virus particles on protoplasts, but could not support cell-to-cell movement in plants. The observations that this mutant MP accumulated to a higher level in the cell than wt MP and did not accumulate in the cell wall opposite infected cells suggest that breakdown or disassembly of tubules in neighbouring, uninfected cells is required for cell-to-cell movement. PMID:14645930

  16. Nephrotoxicity of aminophenols: effects of 4-dimethylaminophenol on isolated rat kidney tubules.

    PubMed

    Szinicz, L; Weger, N; Schneiderhan, W; Kiese, M

    1979-04-23

    In isolated rat kidney tubules DMAP was found to inhibit the gluconeogenesis from lactate, pyruvate, or dihydroxyacetone. The ratio DMAP/protein rather than the calculated concentration of DMAP determined the strength of the effect, 20--25 nmoles DMAP/mg protein inhibiting the rate of gluconeogenesis by about 50%. The inhibition was not reversible. Phenacetin, 4-aminophenol and 4-acetamidophenol were much less effective than DMAP in inhibiting gluconeogenesis in isolated rat kidney tubules. DMAP 14C-labeled in the ring was quickly bound to proteins in kidney tubules. A portion of DMAP which did not exceed about 4 nmoles/mg protein, was bound in compounds soluble in perchloric acid. From this portion tris-GS-DMAP was isolated. DMAP diminished the glutathione content of isolated rat kidney tubules. Reduced glutathione added before DMAP prevented the inhibition of gluconeogenesis and diminished the binding of DMAP to proteins. The binding of DMAP required oxygen and was inhibited by carbon monoxide or cyanide. Several enzymes from isolated kidney tubules were found to be inhibited by DMAP doses which inhibited gluconeogenesis. Large DMAP doses also diminished the sums of ATP + ADP + AMP as well as NAD + NADH and NADP + NADPH. This effect corresponded to an increase in nucleotide degradation products and to increased activity of extracellular LDH. The results indicate that the inhibition of gluconeogenesis by DMAP is not due to a specific effect on one enzyme or on membranes but to unspecific reactions with many substances. PMID:454186

  17. Failed Tubule Recovery, AKI-CKD Transition, and Kidney Disease Progression

    PubMed Central

    Weinberg, Joel M.; Kriz, Wilhelm; Bidani, Anil K.

    2015-01-01

    The transition of AKI to CKD has major clinical significance. As reviewed here, recent studies show that a subpopulation of dedifferentiated, proliferating tubules recovering from AKI undergo pathologic growth arrest, fail to redifferentiate, and become atrophic. These abnormal tubules exhibit persistent, unregulated, and progressively increasing profibrotic signaling along multiple pathways. Paracrine products derived therefrom perturb normal interactions between peritubular capillary endothelium and pericyte-like fibroblasts, leading to myofibroblast transformation, proliferation, and fibrosis as well as capillary disintegration and rarefaction. Although signals from injured endothelium and inflammatory/immune cells also contribute, tubule injury alone is sufficient to produce the interstitial pathology required for fibrosis. Localized hypoxia produced by microvascular pathology may also prevent tubule recovery. However, fibrosis is not intrinsically progressive, and microvascular pathology develops strictly around damaged tubules; thus, additional deterioration of kidney structure after the transition of AKI to CKD requires new acute injury or other mechanisms of progression. Indeed, experiments using an acute-on-chronic injury model suggest that additional loss of parenchyma caused by failed repair of AKI in kidneys with prior renal mass reduction triggers hemodynamically mediated processes that damage glomeruli to cause progression. Continued investigation of these pathologic mechanisms should reveal options for preventing renal disease progression after AKI. PMID:25810494

  18. Quantitative mass spectrometry of diabetic kidney tubules identifies GRAP as a novel regulator of TGFβ signaling

    PubMed Central

    Cummins, Timothy D.; Barati, Michelle T.; Coventry, Susan C.; Salyer, Sarah A.; Klein, Jon B.; Powell, David W.

    2009-01-01

    The aim of this study was to define novel mediators of tubule injury in diabetic kidney disease. For this, we used state-of-the-art proteomic methods combined with a label-free quantitative strategy to define protein expression differences in kidney tubules from transgenic OVE26 type 1 diabetic and control mice. The analysis was performed with diabetic samples that displayed a pro-fibrotic phenotype. We have identified 476 differentially expressed proteins. Bioinformatic analysis indicated several clusters of regulated proteins in relevant functional groups such as TGF-β signaling, tight junction maintenance, oxidative stress, and glucose metabolism. Mass spectrometry detected expression changes of four physiologically relevant proteins were confirmed by immunoblot analysis. Of these, the Grb2-related adaptor protein (GRAP) was up-regulated in kidney tubules from diabetic mice and fibrotic kidneys from diabetic patients, and subsequently confirmed as a novel component of TGF-β signaling in cultured human renal tubule cells. Thus, indicating a potential novel role for GRAP in TGF-β-induced tubule injury in diabetic kidney disease. Although we targeted a specific disease, this approach offers a robust, high-sensitivity methodology that can be applied to the discovery of novel mediators for any experimental or disease condition. PMID:19836472

  19. Golgi Tubule Traffic and the Effects of Brefeldin A Visualized in Living Cells

    PubMed Central

    Sciaky, Noah; Presley, John; Smith, Carolyn; Zaal, Kristien J.M.; Cole, Nelson; Moreira, Jorge E.; Terasaki, Mark; Siggia, Eric; Lippincott-Schwartz, Jennifer

    1997-01-01

    The Golgi complex is a dynamic organelle engaged in both secretory and retrograde membrane traffic. Here, we use green fluorescent protein–Golgi protein chimeras to study Golgi morphology in vivo. In untreated cells, membrane tubules were a ubiquitous, prominent feature of the Golgi complex, serving both to interconnect adjacent Golgi elements and to carry membrane outward along microtubules after detaching from stable Golgi structures. Brefeldin A treatment, which reversibly disassembles the Golgi complex, accentuated tubule formation without tubule detachment. A tubule network extending throughout the cytoplasm was quickly generated and persisted for 5–10 min until rapidly emptying Golgi contents into the ER within 15–30 s. Both lipid and protein emptied from the Golgi at similar rapid rates, leaving no Golgi structure behind, indicating that Golgi membranes do not simply mix but are absorbed into the ER in BFA-treated cells. The directionality of redistribution implied Golgi membranes are at a higher free energy state than ER membranes. Analysis of its kinetics suggested a mechanism that is analogous to wetting or adsorptive phenomena in which a tension-driven membrane flow supplements diffusive transfer of Golgi membrane into the ER. Such nonselective, flow-assisted transport of Golgi membranes into ER suggests that mechanisms that regulate retrograde tubule formation and detachment from the Golgi complex are integral to the existence and maintenance of this organelle. PMID:9382862

  20. Transformation of taxol-stabilized microtubules into inverted tubulin tubules triggered by a tubulin conformation switch

    NASA Astrophysics Data System (ADS)

    Ojeda-Lopez, Miguel A.; Needleman, Daniel J.; Song, Chaeyeon; Ginsburg, Avi; Kohl, Phillip A.; Li, Youli; Miller, Herbert P.; Wilson, Leslie; Raviv, Uri; Choi, Myung Chul; Safinya, Cyrus R.

    2014-02-01

    Bundles of taxol-stabilized microtubules (MTs)—hollow tubules comprised of assembled αβ-tubulin heterodimers—spontaneously assemble above a critical concentration of tetravalent spermine and are stable over long times at room temperature. Here we report that at concentrations of spermine several-fold higher the MT bundles (BMT) quickly become unstable and undergo a shape transformation to bundles of inverted tubulin tubules (BITT), the outside surface of which corresponds to the inner surface of the BMT tubules. Using transmission electron microscopy and synchrotron small-angle X-ray scattering, we quantitatively determined both the nature of the BMT-to-BITT transformation pathway, which results from a spermine-triggered conformation switch from straight to curved in the constituent taxol-stabilized tubulin oligomers, and the structure of the BITT phase, which is formed of tubules of helical tubulin oligomers. Inverted tubulin tubules provide a platform for studies requiring exposure and availability of the inside, luminal surface of MTs to MT-targeted drugs and MT-associated proteins.

  1. Dysferlin stabilizes stress-induced Ca2+ signaling in the transverse tubule membrane

    PubMed Central

    Kerr, Jaclyn P.; Ziman, Andrew P.; Mueller, Amber L.; Muriel, Joaquin M.; Kleinhans-Welte, Emily; Gumerson, Jessica D.; Vogel, Steven S.; Ward, Christopher W.; Roche, Joseph A.; Bloch, Robert J.

    2013-01-01

    Dysferlinopathies, most commonly limb girdle muscular dystrophy 2B and Miyoshi myopathy, are degenerative myopathies caused by mutations in the DYSF gene encoding the protein dysferlin. Studies of dysferlin have focused on its role in the repair of the sarcolemma of skeletal muscle, but dysferlin’s association with calcium (Ca2+) signaling proteins in the transverse (t-) tubules suggests additional roles. Here, we reveal that dysferlin is enriched in the t-tubule membrane of mature skeletal muscle fibers. Following experimental membrane stress in vitro, dysferlin-deficient muscle fibers undergo extensive functional and structural disruption of the t-tubules that is ameliorated by reducing external [Ca2+] or blocking L-type Ca2+ channels with diltiazem. Furthermore, we demonstrate that diltiazem treatment of dysferlin-deficient mice significantly reduces eccentric contraction-induced t-tubule damage, inflammation, and necrosis, which resulted in a concomitant increase in postinjury functional recovery. Our discovery of dysferlin as a t-tubule protein that stabilizes stress-induced Ca2+ signaling offers a therapeutic avenue for limb girdle muscular dystrophy 2B and Miyoshi myopathy patients. PMID:24302765

  2. Interspecific Larval Competition Between Aedes albopictus and Aedes japonicus (Diptera: Culicidae) in Northern Virginia

    PubMed Central

    Armistead, J. S.; Arias, J. R.; Nishimura, N.; Lounibos, L. P.

    2008-01-01

    Aedes albopictus (Skuse) and Aedes japonicus (Theobald) are two of the most recent and widespread invasive mosquito species to have become established in the United States. The two species co-occur in water-filled artificial containers, where crowding and limiting resources are likely to promote inter- or intraspecific larval competition. The performance of northern Virginia populations of Ae. japonicus and Ae. albopictus competing as larvae under field conditions was evaluated. Per capita rates of population increase for each species were estimated, and the effects of species composition and larval density were determined. In water-containing cups provided with oak leaves, Ae. albopictus larvae exhibited a competitive advantage over Ae. japonicus as a consequence of higher survivorship, shorter developmental time, and a significantly higher estimated population growth rate under conditions of interspecific competition. Intraspecific competition constrained population performance of Ae. albopictus significantly more than competition with Ae. japonicus. In the context of the Lotka-Volterra model of competition, these findings suggest competitive exclusion of Ae. japonicus in those habitats where this species co-occurs with Ae. albopictus. PMID:18714861

  3. Comparative study on nocturnal behavior of Aedes aegypti and Aedes albopictus.

    PubMed

    Kawada, Hitoshi; Takemura, Shin-Ya; Arikawa, Kentaro; Takagi, Masahiro

    2005-05-01

    Nocturnal behavior of nonblood-fed females of Aedes aegypti (L.) and Aedes albopictus (Skuse) was studied using an automatic recording device equipped with a photoelectric sensor. Carbon dioxide, heating, and the contrast of the black and white colors were used as attractive cues for mosquitoes. The nocturnal host-seeking activity positively correlated with the increasing light intensity in both species. Ae. aegypti was found to be more sensitive to light than Ae. albopictus. The threshold of light intensity for the activation of the nocturnal host-seeking activity was <0.1 lx (approximately 0.01 foot candle) in Ae. aegypti and >10 lx (approximately 1 foot candle) in Ae. albopictus. Complete darkness during the daytime deactivated the host-seeking activity of both species, irrespective of their increasing flight activity controlled by their intrinsic circadian rhythms. This finding suggested that visual cues are indispensable for host-seeking behavior. The eye parameter value, the product of the ommatidial diameter, and the interommatidial angle were significantly larger in Ae. aegypti than those in Ae. albopictus, indicating that the eye of Ae. aegypti is more adapted to a darker environment. PMID:15962780

  4. Male accessory gland substances from Aedes albopictus affect the locomotor activity of Aedes aegypti females

    PubMed Central

    Lima-Camara, Tamara Nunes; Codeço, Claudia Torres; Honório, Nildimar Alves; Bruno, Rafaela Vieira; Peixoto, Alexandre Afranio; Lounibos, Leon Philip

    2013-01-01

    Dengue is one of the world’s most important mosquito-borne diseases and is usually transmitted by one of two vector species: Aedes aegypti or Aedes albopictus . These two diurnal mosquitoes are frequently found coexisting in similar habitats, enabling interactions between adults, such as cross-mating. The objective of this study was to assess cross-mating between Ae. aegypti females and Ae. albopictus males under artificial conditions and evaluate the locomotor activity of Ae. aegypti virgin females injected with male accessory gland (MAG) homogenates to infer the physiological and behavioural responses to interspecific mating. After seven days of exposure, 3.3-16% of Ae. aegypti females mated with Ae. albopictus males. Virgin Ae. aegypti females injected with conspecific and heterospecific MAGs showed a general decrease in locomotor activity compared to controls and were refractory to mating with conspecific males. The reduction in diurnal locomotor activity induced by injections of conspecific or heterospecific MAGs is consistent with regulation of female reproductive activities by male substances, which are capable of sterilising female Ae. aegypti through satyrisation by Ae. albopictus . PMID:24473799

  5. Autophagy and viral diseases transmitted by Aedes aegypti and Aedes albopictus.

    PubMed

    Carneiro, Leticia A M; Travassos, Leonardo H

    2016-03-01

    Despite a long battle that was started by Oswaldo Cruz more than a century ago, in 1903, Brazil still struggles to fight Aedes aegypti and Aedes albopictus, the mosquito vectors of dengue virus (DENV), Chikungynya virus (CHIKV) and Zika virus (ZIKV). Dengue fever has been a serious public health problem in Brazil for decades, with recurrent epidemic outbreaks occurring during summers. In 2015, until November, 1,534,932 possible cases were reported to the Ministry of Healthv. More recently, the less studied CHIKV and ZIKV have gained attention because of a dramatic increase in their incidence (around 400% for CHIKV) and the association of ZIKV infection with a 11-fold increase in the number of cases of microcephaly from 2014 to 2015 in northeast Brazil (1761 cases until December 2015). The symptoms of these three infections are very similar, which complicates the diagnosis. These include fever, headache, nausea, fatigue, and joint pain. In some cases, DENV infection develops into dengue hemorrhagic fever, a life threatening condition characterized by bleeding and decreases in platelet numbers in the blood. As for CHIKV, the most important complication is joint pain, which can last for months. PMID:26774331

  6. Comparison of the insecticide susceptibilities of laboratory strains of Aedes aegypti and Aedes albopictus.

    PubMed

    Gómez, Andrea; Seccacini, Emilia; Zerba, Eduardo; Licastro, Susana

    2011-12-01

    A susceptible strain of Aedes albopictus derived from the Gainesville strain (Florida, USA) was established in our laboratory. The larvicidal efficacies of the neurotoxic insecticides temephos, permethrin and the pure cis and trans-permethrin isomers and the microbial insecticide Bacillus thuringiensis israelensis (Bti) against Ae. albopictus were estimated and compared to a susceptible strain of Aedes aegypti. The larvicidal effect of insect growth regulator pyriproxyfen was also evaluated in both mosquito strains. The median lethal concentration/median emergency inhibition values for Ae. aegypti and Ae. albopictus, respectively, were: temephos, 3.058 and 6.632 ppb, permethrin, 3.143 and 4.933 ppb, cis-permethrin, 4.457 and 10.068 ppb, trans-permethrin, 1.510 and 3.883 ppb, Bti, 0.655 and 0.880 ppb and pyriproxyfen, 0.00774 and 0.01642 ppb. Ae. albopictus was more tolerant than Ae. aegypti to all six larvicides evaluated. The order of susceptibility for Ae. aegypti was pyriproxyfen > Bti > trans-permethrin > temephos > permethrin > cis-permethrin and for Ae. albopictus was pyriproxyfen > Bti > trans-permethrin > permethrin > temephos > cis-permethrin. Because both species can be found together in common urban, suburban and rural breeding sites, the results of this work provide baseline data on the susceptibility of Ae. albopictus to insecticides commonly used for controlling Ae. aegypti in the field. PMID:22241122

  7. Widespread evidence for interspecific mating between Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in nature.

    PubMed

    Bargielowski, I E; Lounibos, L P; Shin, D; Smartt, C T; Carrasquilla, M C; Henry, A; Navarro, J C; Paupy, C; Dennett, J A

    2015-12-01

    Aedes aegypti and Aedes albopictus, two important vectors of the dengue and chikungunya viruses to humans, often come in contact in their invasive ranges. In these circumstances, a number of factors are thought to influence their population dynamics, including resource competition among the larval stages, prevailing environmental conditions and reproductive interference in the form of satyrization. As the distribution and abundance of Ae. aegypti and Ae. albopictus have profound epidemiological implications, understanding the competitive interactions that influence these patterns in nature is important. While evidence for resource competition and environmental factors had been gathered from the field, the evidence for reproductive interference, though strongly inferred through laboratory trials, remained sparse (one small-scale field trial). In this paper we demonstrate that low rates (1.12-3.73%) of interspecific mating occur in nature among populations of these species that have co-existed sympatrically from 3 to 150yrs. Finally this report contributes a new species-specific primer set for identifying the paternity of sperm extracted from field collected specimens. PMID:26296606

  8. Differentiation of Aedes aegypti and Aedes notoscriptus (Diptera: Culicidae) eggs using scanning electron microscopy.

    PubMed

    Faull, Katherine J; Williams, Craig R

    2016-05-01

    Aedes notoscriptus and Aedes aegypti are both peri-domestic, invasive container-breeding mosquitoes. While the two potential arboviral vectors are bionomically similar, their sympatric distribution in Australia is limited. In this study, analyses of Ae. aegypti and Ae. notoscriptus eggs were enabled using scanning electron microscopy. Significant variations in egg length to width ratio and outer chorionic cell field morphology between Ae. aegypti and Ae. notoscriptus enabled distinction of the two species. Intraspecific variations in cell field morphology also enabled differentiation of the separate populations of both species, highlighting regional and global variation. Our study provides a comprehensive comparative analysis of inter- and intraspecific egg morphological and morphometric variation between two invasive container-breeding mosquitoes. The results indicate a high degree of intraspecific variation in Ae. notoscriptus egg morphology when compared to the eggs of Ae. aegypti. Comparative morphological analyses of Ae. aegypti and Ae. notoscriptus egg attributes using SEM allows differentiation of the species and may be helpful in understanding egg biology in relation to biotope of origin. PMID:26845557

  9. Mathematical model of temephos resistance in Aedes aegypti mosquito population

    NASA Astrophysics Data System (ADS)

    Aldila, D.; Nuraini, N.; Soewono, E.; Supriatna, A. K.

    2014-03-01

    Aedes aegypti is the main vector of dengue disease in many tropical and sub-tropical countries. Dengue became major public concern in these countries due to the unavailability of vaccine or drugs for dengue disease in the market. Hence, the only way to control the spread of DF and DHF is by controlling the vectors carrying the disease, for instance with fumigation, temephos or genetic manipulation. Many previous studies conclude that Aedes aegypti may develop resistance to many kind of insecticide, including temephos. Mathematical model for transmission of temephos resistance in Aedes aegypti population is discussed in this paper. Nontrivial equilibrium point of the system and the corresponding existence are shown analytically. The model analysis have shown epidemiological trends condition that permits the coexistence of nontrivial equilibrium is given analytically. Numerical results are given to show parameter sensitivity and some cases of worsening effect values for illustrating possible conditions in the field.

  10. Effect of temperature on the population dynamics of Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Yusoff, Nuraini; Tokachil, Mohd Najir

    2015-10-01

    Aedes aegypti is one of the main vectors in the transmission of dengue fever. Its abundance may cause the spread of the disease to be more intense. In the study of its biological life cycle, temperature was found to increase the development rate of each stage of this species and thus, accelerate the process of the development from egg to adult. In this paper, a Lefkovitch matrix model will be used to study the stage-structured population dynamics of Aedes aegypti. In constructing the transition matrix, temperature will be taken into account. As a case study, temperature recorded at the Subang Meteorological Station for year 2006 until 2010 will be used. Population dynamics of Aedes aegypti at maximum, average and minimum temperature for each year will be simulated and compared. It is expected that the higher the temperature, the faster the mosquito will breed. The result will be compared to the number of dengue fever incidences to see their relationship.

  11. Stage-Structured Population Dynamics of AEDES AEGYPTI

    NASA Astrophysics Data System (ADS)

    Yusoff, Nuraini; Budin, Harun; Ismail, Salemah

    Aedes aegypti is the main vector in the transmission of dengue fever, a vector-borne disease affecting world population living in tropical and sub-tropical countries. Better understanding of the dynamics of its population growth will help in the efforts of controlling the spread of this disease. In looking at the population dynamics of Aedes aegypti, this paper explored the stage-structured modeling of the population growth of the mosquito using the matrix population model. The life cycle of the mosquito was divided into five stages: eggs, larvae, pupae, adult1 and adult2. Developmental rates were obtained for the average Malaysian temperature and these were used in constructing the transition matrix for the matrix model. The model, which was based only on temperature, projected that the population of Aedes aegypti will blow up with time, which is not realistic. For further work, other factors need to be taken into account to obtain a more realistic result.

  12. Midgut bacterial dynamics in Aedes aegypti.

    PubMed

    Terenius, Olle; Lindh, Jenny M; Eriksson-Gonzales, Karolina; Bussière, Luc; Laugen, Ane T; Bergquist, Helen; Titanji, Kehmia; Faye, Ingrid

    2012-06-01

    In vector mosquitoes, the presence of midgut bacteria may affect the ability to transmit pathogens. We have used a laboratory colony of Aedes aegypti as a model for bacterial interspecies competition and show that after a blood meal, the number of species (culturable on Luria-Bertani agar) that coexist in the midgut is low and that about 40% of the females do not harbor any cultivable bacteria. We isolated species belonging to the genera Bacillus, Elizabethkingia, Enterococcus, Klebsiella, Pantoea, Serratia, and Sphingomonas, and we also determined their growth rates, antibiotic resistance, and ex vivo inhibition of each other. To investigate the possible existence of coadaptation between midgut bacteria and their host, we fed Ae. aegypti cohorts with gut bacteria from human, a frog, and two mosquito species and followed the bacterial population growth over time. The dynamics of the different species suggests coadaptation between host and bacteria, and interestingly, we found that Pantoea stewartii isolated from Ae. aegypti survive better in Ae. aegypti as compared to P. stewartii isolated from the malaria mosquito Anopheles gambiae. PMID:22283178

  13. Successful overwintering of Aedes albopictus in Germany.

    PubMed

    Pluskota, Björn; Jöst, Artur; Augsten, Xenia; Stelzner, Lilith; Ferstl, Ina; Becker, Norbert

    2016-08-01

    The Asian tiger mosquito (Aedes albopictus) is of great concern to public health authorities due to its vector competence and rapid spread across the globe. In 2015, two large local breeding populations of Ae. albopictus were discovered in southwest Germany. In spring 2016, we were able to demonstrate the first evidence of a successful overwintering in Germany of this originally tropical mosquito species in different research projects. Particularly noteworthy is the successful hatching of diapause eggs of an Italian strain (Calabria), which overwintered successfully in the field in St. Georgen im Schwarzwald (Baden-Wuerttemberg) at 820 m above sea level. Furthermore, within the scope of a larvae monitoring, the first larvae that hatched in the field were detected on the April 09, 2016 in a rain barrel within the Heidelberg population. Our first results show that self-extinction due to an unsuccessful overwintering cannot be assumed for populations of the Asian tiger mosquito which settled in Germany in previous years. The evidence of a successful overwintering of a large number of diapause eggs and the hatching of the first larvae in field conditions opens the control year against Ae. albopictus in southwest Germany. PMID:27112761

  14. Do fish repel oviposition by Aedes taeniorhynchus?

    PubMed

    Ritchie, S A; Laidlaw-Bell, C

    1994-09-01

    We tested the hypothesis that fish indirectly control mosquitoes by repelling oviposition. Aedes taeniorhynchus oviposition in mangrove forests, natural pools, and excavated pools with different concentrations of fish was compared. Oviposition in adjacent mangrove forests was concentrated in the site with the lowest fish density. In 3 mangrove forests, egg populations from pool banks were significantly (P < 0.001) lower for pools with fish than for fishless pools, with an overall mean +/- SD of 1.6 +/- 5.7 and 20.0 +/- 34.8 eggs/sample, respectively. At one pool, egg densities increased significantly (P < 0.001) from 0.36 to 5.00 eggs/sample after drying killed fish. In excavated pools, oviposition was significantly (P < 0.001) affected by fish. These data indicate that Ae. taeniorhynchus avoids ovipositing in sites with high concentrations of fish and suggest that the response is fish-mediated. This behavior may help to explain the migratory habits and population dynamics of Ae. taeniorhynchus. PMID:7807080

  15. Effect of Changes in Hydrostatic Pressure in Peritubular Capillaries on the Permeability of the Proximal Tubule

    PubMed Central

    Hayslett, John P.

    1973-01-01

    The effect of increased hydrostatic pressure in the peritubular vessels on net sodium reabsorption from the proximal tubule was examined in the Necturus. An increase in the pressure gradient of 2.0 cm H2O across the wall of the proximal tubule, produced by ligation of the postcaval vein was associated with a marked reduction in net reabsorption and an increased back flux of water and electrolytes. This change was accompanied by a slight, but significant drop in the transepithelial electrical potential but not by an alteration in the steady-state chemical gradient. These studies highlight the importance of changes in the permeability characteristics of the proximal tubule on net sodium transport. Images PMID:4703221

  16. [Effects of sex hormone on the dilatation of urinary tubule and acidophil body in NON mice].

    PubMed

    Sahata, H; Suzuki, S; Ago, A; Mifune, H; Sakamoto, H

    1994-10-01

    The influences of sex hormones on the dilatation of the urinary tubules and acidophil bodies were histologically investigated in NON (Non-Obese Non-diabetic) mice. Although the dilatation of the proximal tubules and acidophil bodies in NON mice were observed only in female but not in male, a slight dilatation and a few bodies were also observed in castrated male NON mice. Moreover, in ovariectomized female NON mice the dilatation and bodies were less compared with intact female NON mice. Estradiol administration induced prominent dilatation and numerous acidophil bodies, while the administration of testosterone showed a complete preventive effect. Therefore, it is suggested that the dilatation of the tubules and the acidophil bodies can be profoundly influenced by sex hormones. PMID:7805803

  17. T-tubule biogenesis and triad formation in skeletal muscle and implication in human diseases

    PubMed Central

    2011-01-01

    In skeletal muscle, the excitation-contraction (EC) coupling machinery mediates the translation of the action potential transmitted by the nerve into intracellular calcium release and muscle contraction. EC coupling requires a highly specialized membranous structure, the triad, composed of a central T-tubule surrounded by two terminal cisternae from the sarcoplasmic reticulum. While several proteins located on these structures have been identified, mechanisms governing T-tubule biogenesis and triad formation remain largely unknown. Here, we provide a description of triad structure and plasticity and review the role of proteins that have been linked to T-tubule biogenesis and triad formation and/or maintenance specifically in skeletal muscle: caveolin 3, amphiphysin 2, dysferlin, mitsugumins, junctophilins, myotubularin, ryanodine receptor, and dihydhropyridine Receptor. The importance of these proteins in triad biogenesis and subsequently in muscle contraction is sustained by studies on animal models and by the direct implication of most of these proteins in human myopathies. PMID:21797990

  18. Microtubule Motors Power Plasma Membrane Tubulation in Clathrin-Independent Endocytosis

    PubMed Central

    Day, Charles A; Baetz, Nicholas W; Copeland, Courtney A; Kraft, Lewis J; Han, Bing; Tiwari, Ajit; Drake, Kimberly R; De Luca, Heidi; Chinnapen, Daniel J-F; Davidson, Michael W; Holmes, Randall K; Jobling, Michael G; Schroer, Trina A; Lencer, Wayne I; Kenworthy, Anne K

    2015-01-01

    How the plasma membrane is bent to accommodate clathrin-independent endocytosis remains uncertain. Recent studies suggest Shiga and cholera toxin induce membrane curvature required for their uptake into clathrin-independent carriers by binding and cross-linking multiple copies of their glycosphingolipid receptors on the plasma membrane. But it remains unclear if toxin-induced sphingolipid crosslinking provides sufficient mechanical force for deforming the plasma membrane, or if host cell factors also contribute to this process. To test this, we imaged the uptake of cholera toxin B-subunit into surface-derived tubular invaginations. We found that cholera toxin mutants that bind to only one glycosphingolipid receptor accumulated in tubules, and that toxin binding was entirely dispensable for membrane tubulations to form. Unexpectedly, the driving force for tubule extension was supplied by the combination of microtubules, dynein and dynactin, thus defining a novel mechanism for generating membrane curvature during clathrin-independent endocytosis. PMID:25690058

  19. Cellular localization of uranium in the renal proximal tubules during acute renal uranium toxicity.

    PubMed

    Homma-Takeda, Shino; Kitahara, Keisuke; Suzuki, Kyoko; Blyth, Benjamin J; Suya, Noriyoshi; Konishi, Teruaki; Terada, Yasuko; Shimada, Yoshiya

    2015-12-01

    Renal toxicity is a hallmark of uranium exposure, with uranium accumulating specifically in the S3 segment of the proximal tubules causing tubular damage. As the distribution, concentration and dynamics of accumulated uranium at the cellular level is not well understood, here, we report on high-resolution quantitative in situ measurements by high-energy synchrotron radiation X-ray fluorescence analysis in renal sections from a rat model of uranium-induced acute renal toxicity. One day after subcutaneous administration of uranium acetate to male Wistar rats at a dose of 0.5 mg uranium kg(-1) body weight, uranium concentration in the S3 segment of the proximal tubules was 64.9 ± 18.2 µg g(-1) , sevenfold higher than the mean renal uranium concentration (9.7 ± 2.4 µg g(-1) ). Uranium distributed into the epithelium of the S3 segment of the proximal tubules and highly concentrated uranium (50-fold above mean renal concentration) in micro-regions was found near the nuclei. These uranium levels were maintained up to 8 days post-administration, despite more rapid reductions in mean renal concentration. Two weeks after uranium administration, damaged areas were filled with regenerating tubules and morphological signs of tissue recovery, but areas of high uranium concentration (100-fold above mean renal concentration) were still found in the epithelium of regenerating tubules. These data indicate that site-specific accumulation of uranium in micro-regions of the S3 segment of the proximal tubules and retention of uranium in concentrated areas during recovery are characteristics of uranium behavior in the kidney. PMID:25772475

  20. Diffusion's Study of Free Ligands Between Vesicle and Tubules Within the Endosome

    NASA Astrophysics Data System (ADS)

    Dagdug, Leonardo

    2005-04-01

    In the mid 80's, Linderman and Lauffenburger suggested that the sorting process of receptors and ligands in the endosome could be explained in terms of pure diffusion. With a reasonable choice of parameters in their model, they were led to the prediction that by the sorting time most of the receptors are in the tubule while the ligands apparently equilibrate throughout the vesicle and tubule volumes. The fraction of receptor predicted by their model is in excellent agreement with experimental observations. To calculate the mean capture time for the ligands they studied the case when the entrance of the tubule is an absorbing boundary. They solved a Poisson's equation inside a sphere with mixed boundary conditions. This neglects the ligand return probability to the vesicle from the tubules, and vice versa. Under this assumptions they predict that by the sorting time around 70-60% of the ligands remain in the vesicle. In contrast with their prediction, the experimental observation is that most of the ligand molecules remain in the vesicle by the sorting time, typically degraded and routed to the lysosome. In this work we focus in ligand's diffusion within the vesicle. We extend Linderman and Lauffenburger's model including the effect of the presence of the tubules in the system, allowing the ligands to diffuse between the vesicle and the tubules. The principal biological implication of this extension, is that by the sorting time around 91% of the ligands remain in the vesicle. It means, that they can go many times from one chamber to the other before it is removed from the system. The validity of approximations was checked by simulations that indicated excellent agreement between analytical and numerical results.

  1. A mathematical model of rat proximal tubule and loop of Henle.

    PubMed

    Weinstein, Alan M

    2015-05-15

    Proximal tubule and loop of Henle function are coupled, with proximal transport determining loop fluid composition, and loop transport modulating glomerular filtration via tubuloglomerular feedback (TGF). To examine this interaction, we begin with published models of the superficial rat proximal convoluted tubule (PCT; including flow-dependent transport in a compliant tubule), and the rat thick ascending Henle limb (AHL). Transport parameters for this PCT are scaled down to represent the proximal straight tubule (PST), which is connected to the thick AHL via a short descending limb. Transport parameters for superficial PCT and PST are scaled up for a juxtamedullary nephron, and connected to AHL via outer and inner medullary descending limbs, and inner medullary thin AHL. Medullary interstitial solute concentrations are specified. End-AHL hydrostatic pressure is determined by distal nephron flow resistance, and the TGF signal is represented as a linear function of end-AHL cytosolic Cl concentration. These two distal conditions required iterative solution of the model. Model calculations capture inner medullary countercurrent flux of urea, and also suggest the presence of an outer medullary countercurrent flux of ammonia, with reabsorption in AHL and secretion in PST. For a realistically strong TGF signal, there is the expected homeostatic impact on distal flows, and in addition, a homeostatic effect on proximal tubule pressure. The model glycosuria threshold is compatible with rat data, and predicted glucose excretion with selective 1Na(+):1glucose cotransporter (SGLT2) inhibition comports with observations in the mouse. Model calculations suggest that enhanced proximal tubule Na(+) reabsorption during hyperglycemia is sufficient to activate TGF and contribute to diabetic hyperfiltration. PMID:25694479

  2. Mutual association of Broad bean wilt virus 2 VP37-derived tubules and plasmodesmata obtained from cytological observation

    PubMed Central

    Xie, Li; Shang, Weina; Liu, Chengke; Zhang, Qinfen; Sunter, Garry; Hong, Jian; Zhou, Xueping

    2016-01-01

    The movement protein VP37 of broad bean wilt virus 2 (BBWV 2) forms tubules in the plasmodesmata (PD) for the transport of virions between cells. This paper reports a mutual association between the BBWV 2 VP37-tubule complex and PD at the cytological level as determined by transmission electron microscopy. The generation of VP37-tubules within different PD leads to a different occurrence frequency as well as different morphology lines of virus-like particles. In addition, the frequency of VP37-tubules was different between PD found at different cellular interfaces, as well as between single-lined PD and branched PD. VP37-tubule generation also induced structural alterations of PD as well as modifications to the cell wall (CW) in the vicinity of the PD. A structural comparison using three-dimensional (3D) electron tomography (ET), determined that desmotubule structures found in the center of normal PD were absent in PD containing VP37-tubules. Using gold labeling, modification of the CW by callose deposition and cellulose reduction was observable on PD containing VP37-tubule. These cytological observations provide evidence of a mutual association of MP-derived tubules and PD in a natural host, improving our fundamental understanding of interactions between viral MP and PD that result in intercellular movement of virus particles. PMID:26903400

  3. Mutual association of Broad bean wilt virus 2 VP37-derived tubules and plasmodesmata obtained from cytological observation.

    PubMed

    Xie, Li; Shang, Weina; Liu, Chengke; Zhang, Qinfen; Sunter, Garry; Hong, Jian; Zhou, Xueping

    2016-01-01

    The movement protein VP37 of broad bean wilt virus 2 (BBWV 2) forms tubules in the plasmodesmata (PD) for the transport of virions between cells. This paper reports a mutual association between the BBWV 2 VP37-tubule complex and PD at the cytological level as determined by transmission electron microscopy. The generation of VP37-tubules within different PD leads to a different occurrence frequency as well as different morphology lines of virus-like particles. In addition, the frequency of VP37-tubules was different between PD found at different cellular interfaces, as well as between single-lined PD and branched PD. VP37-tubule generation also induced structural alterations of PD as well as modifications to the cell wall (CW) in the vicinity of the PD. A structural comparison using three-dimensional (3D) electron tomography (ET), determined that desmotubule structures found in the center of normal PD were absent in PD containing VP37-tubules. Using gold labeling, modification of the CW by callose deposition and cellulose reduction was observable on PD containing VP37-tubule. These cytological observations provide evidence of a mutual association of MP-derived tubules and PD in a natural host, improving our fundamental understanding of interactions between viral MP and PD that result in intercellular movement of virus particles. PMID:26903400

  4. Molecular Mechanism of Membrane Constriction and Tubulation Mediated by the F-BAR Protein Pacsin/Syndapin

    SciTech Connect

    Wang, Q.; Navarro, M; Peng, G; Molinelli, E; Lin, G; Judson, B; Rajashankar, K; Sondermann, H

    2009-01-01

    Peripheral membrane proteins of the Bin/amphiphysin/Rvs (BAR) and Fer-CIP4 homology-BAR (F-BAR) family participate in cellular membrane trafficking and have been shown to generate membrane tubules. The degree of membrane bending appears to be encoded in the structure and immanent curvature of the particular protein domains, with BAR and F-BAR domains inducing high- and low-curvature tubules, respectively. In addition, oligomerization and the formation of ordered arrays influences tubule stabilization. Here, the F-BAR domain-containing protein Pacsin was found to possess a unique activity, creating small tubules and tubule constrictions, in addition to the wide tubules characteristic for this subfamily. Based on crystal structures of the F-BAR domain of Pacsin and mutagenesis studies, vesiculation could be linked to the presence of unique structural features distinguishing it from other F-BAR proteins. Tubulation was suppressed in the context of the full-length protein, suggesting that Pacsin is autoinhibited in solution. The regulated deformation of membranes and promotion of tubule constrictions by Pacsin suggests a more versatile function of these proteins in vesiculation and endocytosis beyond their role as scaffold proteins.

  5. The role of plasmodesma-located proteins in tubule-guided virus transport is limited to the plasmodesmata.

    PubMed

    den Hollander, P W; Kieper, S N; Borst, J W; van Lent, J W M

    2016-09-01

    Intercellular spread of plant viruses involves passage of the viral genome or virion through a plasmodesma (PD). Some viruses severely modify the PD structure, as they assemble a virion carrying tubule composed of the viral movement protein (MP) inside the PD channel. Successful modulation of the host plant to allow infection requires an intimate interaction between viral proteins and both structural and regulatory host proteins. To date, however, very few host proteins are known to promote virus spread. Plasmodesmata-located proteins (PDLPs) localised in the PD have been shown to contribute to tubule formation in cauliflower mosaic virus and grapevine fanleaf virus infections. In this study, we have investigated the role of PDLPs in intercellular transport of another tubule-forming virus, cowpea mosaic virus. The MP of this virus was found to interact with PDLPs in the PD, as was shown for other tubule-forming viruses. Expression of PDLPs and MPs in protoplasts in the absence of a PD revealed that these proteins do not co-localise at the site of tubule initiation. Furthermore, we show that tubule assembly in protoplasts does not require an interaction with PDLPs at the base of the tubule, as has been observed in planta. These results suggest that a physical interaction between MPs and PDLPs is not required for assembly of the movement tubule and that the beneficial role of PDLPs in virus movement is confined to the structural context of the PD. PMID:27339685

  6. Burchellin: study of bioactivity against Aedes aegypti

    PubMed Central

    2014-01-01

    Background The dengue mosquito Aedes aegypti Linnaeus, 1762 is a widespread insect pest of serious medical importance. Since no effective vaccine is available for treating dengue, the eradication or control of the main mosquito vector is regarded as essential. Since conventional insecticides have limited success, plants may be an alternative source of larvicidal agents, since they contain a rich source of bioactive chemicals. The aim of this study was to evaluate the larvicidal activity of the neolignan burchellin isolated from Ocotea cymbarum (Lauraceae), a plant from the Amazon region, against third instar larvae of A. aegypti. Methods Burchellin obtained from O. cymbarum was analyzed. The inhibitory activity against A. aegypti eggs and larvae and histological changes in the digestive system of treated L3 larvae were evaluated. In addition, nitric oxide synthase activity and nitric oxide levels were determined, and cytotoxicity bioassays performed. Results The data showed that burchellin interfered with the development cycle of the mosquito, where its strongest toxic effect was 100% mortality in larvae (L3) at concentrations ≥ 30 ppm. This compound did not show target cell toxicity in peritoneal macrophages from BALB/c mice, and proved to have molecular stability when dissolved in water. The L3 and L4 larvae treated with the compound showed cellular destruction and disorganization, cell spacing, and vacuolization of epithelial cells in small regions of the midgut. Conclusion The neolignan burchellin proved to be a strong candidate for a natural, safe and stable phytolarvicidal to be used in population control of A. aegypti. PMID:24713267

  7. [Various biological properties of Aedes cantans irides iridescent virus].

    PubMed

    Bachatskiĭ, L P; Sherban, S D

    1976-01-01

    The sedimentation coefficient, molecular weight and the type of nucleic acid of Aedes cantans iridescence virus were determined, and its proteins were analysed in a dissociating system by electrophoresis in polyacylamide gel. Ultrathin sections of affected larvae were examined. PMID:1007219

  8. Area-wide management of Aedes albopictus: lessons learned.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aedes albopictus, the Asian tiger mosquito, is the principal vector of chikungunya fever and a critical vector of dengue. This daytime biting pest often causes the majority of service requests from urban and suburban residents in New Jersey and many other states and nations where it has spread. Ou...

  9. First Record of Aedes albopictus in Sinaloa, Mexico.

    PubMed

    Torres-Avendaño, Jose I; Castillo-Ureta, Hipolito; Torres-Montoya, Edith H; Meza-Carrillo, Elizabeth; Lopez-Mendoza, Reyna L; Vazquez-Martinez, Maria G; Rendon-Maldonado, Jose G

    2015-06-01

    We report here the discovery of Aedes albopictus for the first time in Sinaloa state, Mexico. The mosquito larvae were collected from small water containers in the urban area of Culiacan city, Sinaloa state. Identification of the species was done primarily by morphology, followed by confirmation with polymerase-chain-reaction-based molecular method. PMID:26181692

  10. Cytochromr b expression and RNAi knockdown in Aedes aegypti.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cytochrome b, coded by mitochondrial DNA, is one of the cytochromes involved in the electron transport in the respiratory chain of mitochondria. Cytochrome b is a critical intermediate in mitoptosis, i.e. a mitochondrial death pathway. To reveal whether cytochrome b of the mosquito Aedes aegypti (Ae...

  11. A review on symmetries for certain Aedes aegypti models

    NASA Astrophysics Data System (ADS)

    Freire, Igor Leite; Torrisi, Mariano

    2015-04-01

    We summarize our results related with mathematical modeling of Aedes aegypti and its Lie symmetries. Moreover, some explicit, group-invariant solutions are also shown. Weak equivalence transformations of more general reaction diffusion systems are also considered. New classes of solutions are obtained.

  12. Reappearance of Aedes aegypti (Diptera: Culicidae) in Lima, Peru.

    PubMed

    Andrade, C S; Cáceres, A G; Vaquerizo, A; Ibañez-Bernal, S; Cachay, L S

    2001-07-01

    We report here the reappearance of Aedes aegypti in the Rimac district, and summarize the history of this mosquito species in Peru since its first detection in 1852. On March 17 2000 were found Ae. aegypti and Culex quinquefasciatus in Mariscal Castilla town, Flor de Amancaes, San Juan de Amancaes, El Altillo and Santa Rosa in the Rimac district, Lima Province. PMID:11500764

  13. Pyrethroid resistance is widespread among Florida populations of Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aedes aegypti is an efficient vector of a number of diseases that affect man and is of increasing concern because of the reemergence of dengue and recent identification of locally acquired chikungunya in Florida. Pesticide resistance in this species has been demonstrated in several neighboring coun...

  14. Functional development of the octenol response in aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Attraction of female Aedes aegypti mosquitoes to 1-octen-3-ol (octenol), CO2, lactic acid or ammonia emitted by vertebrate hosts is not only contingent on the presence of odorants in the environment, but is also influenced by the insect’s physiological state. For anautogenous mosquito species, lik...

  15. Permethrin induces overexpression of multiple genes in Aedes aegypti.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using the PCR-select subtractive cDNA hybridization technique, 18 different genes were isolated from a permethrin-treated vs acetone-treated Aedes aegypti subtractive library. QPCR results revealed that eight of the 18 gene’s transcriptional levels in permethrin-treated Ae. aegypti were at least 2- ...

  16. Invasion of cemeteries in Florida by Aedes albopictus.

    PubMed

    O'Meara, G F; Gettman, A D; Evans, L F; Scheel, F D

    1992-03-01

    Aedes albopictus has been found in 53 of the 67 Florida counties. The initial discoveries in 11 of these counties were made in cemeteries. At several locations, Ae. albopictus became well-established in cemeteries before appearing in nearby accumulations of waste tires. The recycling of plastic floral baskets may be aiding the spread of Ae. albopictus. Mosquitoes were commonly found in all types of flower-holding containers in cemeteries, except bronze vases. In the laboratory, most Aedes aegypti eggs laid in bronze vases hatched, but larvae subsequently died. The spread of Ae. albopictus in cemeteries seems to occur at the expense of Ae. aegypti populations. At one cemetery immature Ae. albopictus and Ae. aegypti were found in about 70% of the Aedes-positive containers at the start of a monitoring program. In subsequent collections from this site, Ae. albopictus was found in nearly all Aedes-positive containers, whereas there was a progressive decrease in containers with Ae. aegypti. This trend did not appear to be the result of any seasonal pattern because in a nearby cemetery where Ae. albopictus was absent, Ae. aegypti did not show a similar decline. Limiting flower-holding containers to those with drain holes or to bronze vases would greatly limit mosquito production. PMID:1583479

  17. Differential Susceptibilities of Aedes aegypti and Aedes albopictus from the Americas to Zika Virus

    PubMed Central

    Vazeille, Marie; Yebakima, André; Girod, Romain; Goindin, Daniella; Dupont-Rouzeyrol, Myrielle; Lourenço-de-Oliveira, Ricardo; Failloux, Anna-Bella

    2016-01-01

    Background Since the major outbreak in 2007 in the Yap Island, Zika virus (ZIKV) causing dengue-like syndromes has affected multiple islands of the South Pacific region. In May 2015, the virus was detected in Brazil and then spread through South and Central America. In December 2015, ZIKV was detected in French Guiana and Martinique. The aim of the study was to evaluate the vector competence of the mosquito spp. Aedes aegypti and Aedes albopictus from the Caribbean (Martinique, Guadeloupe), North America (southern United States), South America (Brazil, French Guiana) for the currently circulating Asian genotype of ZIKV isolated from a patient in April 2014 in New Caledonia. Methodology/Principal Findings Mosquitoes were orally exposed to an Asian genotype of ZIKV (NC-2014-5132). Upon exposure, engorged mosquitoes were maintained at 28°±1°C, a 16h:8h light:dark cycle and 80% humidity. 25–30 mosquitoes were processed at 4, 7 and 14 days post-infection (dpi). Mosquito bodies (thorax and abdomen), heads and saliva were analyzed to measure infection, dissemination and transmission, respectively. High infection but lower disseminated infection and transmission rates were observed for both Ae. aegypti and Ae. albopictus. Ae. aegypti populations from Guadeloupe and French Guiana exhibited a higher dissemination of ZIKV than the other Ae. aegypti populations examined. Transmission of ZIKV was observed in both mosquito species at 14 dpi but at a low level. Conclusions/Significance This study suggests that although susceptible to infection, Ae. aegypti and Ae. albopictus were unexpectedly low competent vectors for ZIKV. This may suggest that other factors such as the large naïve population for ZIKV and the high densities of human-biting mosquitoes contribute to the rapid spread of ZIKV during the current outbreak. PMID:26938868

  18. Mitochondrial and Metabolic Dysfunction in Renal Convoluted Tubules of Obese Mice: Protective Role of Melatonin

    PubMed Central

    Giugno, Lorena; Lavazza, Antonio; Reiter, Russel J.; Rodella, Luigi Fabrizio; Rezzani, Rita

    2014-01-01

    Obesity is a common and complex health problem, which impacts crucial organs; it is also considered an independent risk factor for chronic kidney disease. Few studies have analyzed the consequence of obesity in the renal proximal convoluted tubules, which are the major tubules involved in reabsorptive processes. For optimal performance of the kidney, energy is primarily provided by mitochondria. Melatonin, an indoleamine and antioxidant, has been identified in mitochondria, and there is considerable evidence regarding its essential role in the prevention of oxidative mitochondrial damage. In this study we evaluated the mechanism(s) of mitochondrial alterations in an animal model of obesity (ob/ob mice) and describe the beneficial effects of melatonin treatment on mitochondrial morphology and dynamics as influenced by mitofusin-2 and the intrinsic apoptotic cascade. Melatonin dissolved in 1% ethanol was added to the drinking water from postnatal week 5–13; the calculated dose of melatonin intake was 100 mg/kg body weight/day. Compared to control mice, obesity-related morphological alterations were apparent in the proximal tubules which contained round mitochondria with irregular, short cristae and cells with elevated apoptotic index. Melatonin supplementation in obese mice changed mitochondria shape and cristae organization of proximal tubules, enhanced mitofusin-2 expression, which in turn modulated the progression of the mitochondria-driven intrinsic apoptotic pathway. These changes possibly aid in reducing renal failure. The melatonin-mediated changes indicate its potential protective use against renal morphological damage and dysfunction associated with obesity and metabolic disease. PMID:25347680

  19. Stress initiated during isolation of rat renal proximal tubules limits in vitro survival.

    PubMed

    Green, C E; Dabbs, J E; Tyson, C A; Rauckman, E J

    1990-01-01

    The effects of oxidative damage were assessed in rat proximal tubule fragments (isolated by collagenase perfusion) by monitoring lactate dehydrogenase release (LDH-R) to measure cell viability and thiobarbituric acid (TBA) reactive material to follow oxidative damage. Increasing the oxygen content in the incubation atmosphere from 10 to 95% significantly increased LDH-R and TBA reactants. Addition of butylated hydroxytoluene or deferoxamine (DF) to the medium prevented these changes, but ascorbic acid or mannitol had no positive effect. Lima bean trypsin inhibitor also reduced LDH leakage significantly when added to the medium, but not when added to the perfusion buffers. In contrast, adding DF to the perfusate during tubule isolation produced the most pronounced benefit; net LDH-R after 4 hr was about 10% in tubules prepared this way compared to 20% when DF was omitted. Basal oxygen consumption declined to approximately the same extent as LDH-R increased. Maintenance of nystatin-stimulated respiration, ATP/ADP, GSH content and total adenine nucleotides indicated good cell function. These results suggest that oxidative damage initiated during the tubule isolation procedure limits cell survival but this effect can be counteracted substantially by the addition of DF to the perfusion buffer. PMID:1962872

  20. Grouper tshβ Promoter-Driven Transgenic Zebrafish Marks Proximal Kidney Tubule Development

    PubMed Central

    Wang, Yang; Sun, Zhi-Hui; Zhou, Li; Li, Zhi; Gui, Jian-Fang

    2014-01-01

    Kidney tubule plays a critical role in recovering or secreting solutes, but the detailed morphogenesis remains unclear. Our previous studies have found that grouper tshβ (gtshβ) is also expressed in kidney, however, the distribution significance is still unknown. To understand the gtshβ role and kidney tubule morphogenesis, here, we have generated a transgenic zebrafish line Tg(gtshβ:GFP) with green fluorescent protein driven by the gtshβ promoter. Similar to the endogenous tshβ in zebrafish or in grouper, the gtshβ promoter-driven GFP is expressed in pituitary and kidney, and the developing details of proximal kidney tubule are marked in the transgenic zebrafish line. The gfp initially transcribes at 16 hours post fertilization (hpf) above the dorsal mesentery, and partially co-localizes with pronephric tubular markers slc20a1a and cdh17. Significantly, the GFP specifically localizes in proximal pronephric segments during embryogenesis and resides at kidney duct epithelium in adult fish. To test whether the gtshβ promoter-driven GFP may serve as a readout signal of the tubular development, we have treated the embryos with retinoic acid signaing (RA) reagents, in which exogenous RA addition results in a distal extension of the proximal segments, while RA inhibition induces a weakness and shortness of the proximal segments. Therefore, this transgenic line provides a useful tool for genetic or chemical analysis of kidney tubule. PMID:24905828

  1. mTOR controls lysosome tubulation and antigen presentation in macrophages and dendritic cells

    PubMed Central

    Saric, Amra; Hipolito, Victoria E. B.; Kay, Jason G.; Canton, Johnathan; Antonescu, Costin N.; Botelho, Roberto J.

    2016-01-01

    Macrophages and dendritic cells exposed to lipopolysaccharide (LPS) convert their lysosomes from small, punctate organelles into a network of tubules. Tubular lysosomes have been implicated in phagosome maturation, retention of fluid phase, and antigen presentation. There is a growing appreciation that lysosomes act as sensors of stress and the metabolic state of the cell through the kinase mTOR. Here we show that LPS stimulates mTOR and that mTOR is required for LPS-induced lysosome tubulation and secretion of major histocompatibility complex II in macrophages and dendritic cells. Specifically, we show that the canonical phosphatidylinositol 3-kinase–Akt–mTOR signaling pathway regulates LPS-induced lysosome tubulation independently of IRAK1/4 and TBK. Of note, we find that LPS treatment augmented the levels of membrane-associated Arl8b, a lysosomal GTPase required for tubulation that promotes kinesin-dependent lysosome movement to the cell periphery, in an mTOR-dependent manner. This suggests that mTOR may interface with the Arl8b-kinesin machinery. To further support this notion, we show that mTOR antagonists can block outward movement of lysosomes in cells treated with acetate but have no effect in retrograde movement upon acetate removal. Overall our work provides tantalizing evidence that mTOR plays a role in controlling lysosome morphology and trafficking by modulating microtubule-based motor activity in leukocytes. PMID:26582390

  2. SGLT2 Inhibitors: Glucotoxicity and Tumorigenesis Downstream the Renal Proximal Tubule?

    PubMed

    Bertinat, Romina; Nualart, Francisco; Yáñez, Alejandro J

    2016-08-01

    At present, diabetes mellitus is the main cause of end-stage renal disease. Effective glycaemic management is the most powerful tool to delay the establishment of diabetic complications, such as diabetic kidney disease. Together with reducing blood glucose levels, new anti-diabetic agents are expected not only to control the progression but also to restore known defects of the diabetic kidney. Sodium-glucose co-transporter 2 (SGLT2) inhibitors are promising anti-diabetic agents that reduce hyperglycaemia by impairing glucose reabsorption in proximal tubule of the kidney and increasing glucosuria. SGLT2 inhibitors have shown to reduce glucotoxicity in isolated proximal tubule cells and also to attenuate expression of markers of overall kidney damage in experimental animal models of diabetes, but the actual renoprotective effect for downstream nephron segments is still unknown and deserves further attention. Here, we briefly discuss possible undesired effects of enhanced glucosuria and albuminuria in nephron segments beyond the proximal tubule after SGLT2 inhibitor treatment, offering new lines of research to further understand the renoprotective action of these anti-diabetic agents. Strategies blocking glucose reabsorption by renal proximal tubule epithelial cells (RPTEC) may be protective for RPTEC, but downstream nephron segments will still be exposed to high glucose and albumin levels through the luminal face. The actual effect of constant enhanced glucosuria over distal nephron segments remains to be established. J. Cell. Physiol. 231: 1635-1637, 2016. © 2015 Wiley Periodicals, Inc. PMID:26661279

  3. Revealing T-Tubules in Striated Muscle with New Optical Super-Resolution Microscopy Techniquess.

    PubMed

    Jayasinghe, Isuru D; Clowsley, Alexander H; Munro, Michelle; Hou, Yufeng; Crossman, David J; Soeller, Christian

    2015-01-01

    The t-tubular system plays a central role in the synchronisation of calcium signalling and excitation-contraction coupling in most striated muscle cells. Light microscopy has been used for imaging t-tubules for well over 100 years and together with electron microscopy (EM), has revealed the three-dimensional complexities of the t-system topology within cardiomyocytes and skeletal muscle fibres from a range of species. The emerging super-resolution single molecule localisation microscopy (SMLM) techniques are offering a near 10-fold improvement over the resolution of conventional fluorescence light microscopy methods, with the ability to spectrally resolve nanometre scale distributions of multiple molecular targets. In conjunction with the next generation of electron microscopy, SMLM has allowed the visualisation and quantification of intricate t-tubule morphologies within large areas of muscle cells at an unprecedented level of detail. In this paper, we review recent advancements in the t-tubule structural biology with the utility of various microscopy techniques. We outline the technical considerations in adapting SMLM to study t-tubules and its potential to further our understanding of the molecular processes that underlie the sub-micron scale structural alterations observed in a range of muscle pathologies. PMID:26913143

  4. mTOR controls lysosome tubulation and antigen presentation in macrophages and dendritic cells.

    PubMed

    Saric, Amra; Hipolito, Victoria E B; Kay, Jason G; Canton, Johnathan; Antonescu, Costin N; Botelho, Roberto J

    2016-01-15

    Macrophages and dendritic cells exposed to lipopolysaccharide (LPS) convert their lysosomes from small, punctate organelles into a network of tubules. Tubular lysosomes have been implicated in phagosome maturation, retention of fluid phase, and antigen presentation. There is a growing appreciation that lysosomes act as sensors of stress and the metabolic state of the cell through the kinase mTOR. Here we show that LPS stimulates mTOR and that mTOR is required for LPS-induced lysosome tubulation and secretion of major histocompatibility complex II in macrophages and dendritic cells. Specifically, we show that the canonical phosphatidylinositol 3-kinase-Akt-mTOR signaling pathway regulates LPS-induced lysosome tubulation independently of IRAK1/4 and TBK. Of note, we find that LPS treatment augmented the levels of membrane-associated Arl8b, a lysosomal GTPase required for tubulation that promotes kinesin-dependent lysosome movement to the cell periphery, in an mTOR-dependent manner. This suggests that mTOR may interface with the Arl8b-kinesin machinery. To further support this notion, we show that mTOR antagonists can block outward movement of lysosomes in cells treated with acetate but have no effect in retrograde movement upon acetate removal. Overall our work provides tantalizing evidence that mTOR plays a role in controlling lysosome morphology and trafficking by modulating microtubule-based motor activity in leukocytes. PMID:26582390

  5. Mammalian Target of Rapamycin Mediates Kidney Injury Molecule 1-Dependent Tubule Injury in a Surrogate Model.

    PubMed

    Yin, Wenqing; Naini, Said Movahedi; Chen, Guochun; Hentschel, Dirk M; Humphreys, Benjamin D; Bonventre, Joseph V

    2016-07-01

    Kidney injury molecule 1 (KIM-1), an epithelial phagocytic receptor, is markedly upregulated in the proximal tubule in various forms of acute and chronic kidney injury in humans and many other species. Whereas acute expression of KIM-1 has adaptive anti-inflammatory effects, chronic expression may be maladaptive in mice. Here, we characterized the zebrafish Kim family, consisting of Kim-1, Kim-3, and Kim-4. Kim-1 was markedly upregulated in kidney after gentamicin-induced injury and had conserved phagocytic activity in zebrafish. Both constitutive and tamoxifen-induced expression of Kim-1 in zebrafish kidney tubules resulted in loss of the tubule brush border, reduced GFR, pericardial edema, and increased mortality. Kim-1-induced kidney injury was associated with reduction of growth of adult fish. Kim-1 expression led to activation of the mammalian target of rapamycin (mTOR) pathway, and inhibition of this pathway with rapamycin increased survival. mTOR pathway inhibition in KIM-1-overexpressing transgenic mice also significantly ameliorated serum creatinine level, proteinuria, tubular injury, and kidney inflammation. In conclusion, persistent Kim-1 expression results in chronic kidney damage in zebrafish through a mechanism involving mTOR. This observation predicted the role of the mTOR pathway and the therapeutic efficacy of mTOR-targeted agents in KIM-1-mediated kidney injury and fibrosis in mice, demonstrating the utility of the Kim-1 renal tubule zebrafish models. PMID:26538632

  6. Lipid phase of transverse tubule membranes from skeletal muscle. An electron paramagnetic resonance study.

    PubMed Central

    Hidalgo, C

    1985-01-01

    The lipid phase of transverse tubule membrane was probed with a variety of fatty acid spin labels. The motion of the probe increased as the distance between the spin label and polar head group increased, in agreement with results reported in other membranes. The value of the order parameter at 37 degrees C for a fatty acid spin label containing the label attached to its fifth carbon atom was closer to values reported for bacterial membranes than to the lower values reported for other mammalian membranes. Order parameters for spin labels containing the label nearer to the center of the bilayer were closer to the values reported in other mammalian membranes than to values reported for bacterial membranes. These results indicate that the lipid segments in the vicinity of the polar head group, and less so those near the center of the bilayer, are motionally more restricted in transverse tubules than in other mammalian membranes. In particular, the lipid phase of the transverse tubule membrane is less fluid than that of the sarcoplasmic reticulum membrane. A possible role of the high cholesterol content of transverse tubules in generating the lower fluidity of its lipid phase is discussed. PMID:2990585

  7. Current understanding ofI sperm-storage tubule (SST) function

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Unlike most mammals, birds do not need to synchronize copulation with ovulation. Hens are endowed with tubular structures, the sperm-storage tubules (SST), in their oviducts which the sperm enter and survive for weeks after mating or artificial insemination. Sperm are slowly but continually releas...

  8. Effect of epsilon toxin-GFP on MDCK cells and renal tubules in vivo.

    PubMed

    Soler-Jover, Alex; Blasi, Juan; Gómez de Aranda, Inma; Navarro, Piedad; Gibert, Maryse; Popoff, Michel R; Martín-Satué, Mireia

    2004-07-01

    Epsilon toxin (epsilon-toxin), produced by Clostridium perfringens types B and D, causes fatal enterotoxemia, also known as pulpy kidney disease, in livestock. Recombinant epsilon-toxin-green fluorescence protein (epsilon-toxin-GFP) and epsilon-prototoxin-GFP were successfully expressed in Escherichia coli. MTT assays on MDCK cells confirmed that recombinant epsilon-toxin-GFP retained the cytotoxicity of the native toxin. Direct fluorescence analysis of MDCK cells revealed a homogeneous peripheral pattern that was temperature sensitive and susceptible to detergent. epsilon-Toxin-GFP and epsilon-prototoxin-GFP bound to endothelia in various organs of injected mice, especially the brain. However, fluorescence mainly accumulated in kidneys. Mice injected with epsilon-toxin-GFP showed severe kidney alterations, including hemorrhagic medullae and selective degeneration of distal tubules. Moreover, experiments on kidney cryoslices demonstrated specific binding to distal tubule cells of a range of species. We demonstrate with new recombinant fluorescence tools that epsilon-toxin binds in vivo to endothelial cells and renal tubules, where it has a strong cytotoxic effect. Our binding experiments indicate that an epsilon-toxin receptor is expressed on renal distal tubules of mammalian species, including human. PMID:15208360

  9. Identification of proteins associated with adhesive prints from Holothuria dofleinii Cuvierian tubules.

    PubMed

    Peng, Yong Y; Glattauer, Veronica; Skewes, Timothy D; McDevitt, Andrew; Elvin, Christopher M; Werkmeister, Jerome A; Graham, Lloyd D; Ramshaw, John A M

    2014-12-01

    Cuvierian tubules are expelled as a defence mechanism against predators by various species within the family Holothuridae. When the tubules are expelled, they become sticky almost immediately and ensnare the predator. The mechanism of this rapid adhesion is not clear, but proteins on the surface of the expelled tubules are widely believed to be involved. This study has examined such proteins from Holothuria dofleinii, sourced from adhesive prints left on glass after the removal of adhered tubules. Gel electrophoresis showed that seven strongly staining protein bands were consistently present in all samples, with molecular masses ranging from 89 to 17 kDa. N-terminal sequence data was obtained from two bands, while others seemed blocked. Tandem mass spectrometry-based sequencing of tryptic peptides derived from individual protein bands indicated that the proteins were unlikely to be homopolymers. PCR primers designed using the peptide sequences enabled us to amplify, clone and sequence cDNA segments relating to four gel bands; for each, the predicted translation product contained other peptide sequences observed for that band that had not been used in primer design. Database searches using the peptide and cDNA-encoded sequences suggest that two of the seven proteins are novel and one is a C-type lectin, while-surprisingly-at least three of the other four are closely related to enzymes associated with the pentose phosphate cycle and glycolysis. We discuss precedents in which lectins and metabolic enzymes are involved in attachment and adhesion phenomena. PMID:25086572

  10. Antigens of the basement membranes of the seminiferous tubules induce autoimmunity in Wistar rats.

    PubMed

    Lustig, L; Satz, M L; Sztein, M B; Denduchis, B

    1982-05-01

    A preparation enriched in basement membranes from seminiferous tubules was isolated from rat testes (STBM) and injected with complete Freund's adjuvant into Wistar rats. In 60% of animals a mild multifocal orchitis was observed. In damaged areas, perivascular and peritubular mononuclear cell infiltrates and different degrees of cell sloughing of some seminiferous tubules were observed. Electron microscopy revealed focal thickenings and delamination of the basement membrane of the seminiferous tubules as well as vacuolization of Sertoli cell cytoplasm. Using immunofluorescence discontinuous linear deposits of IgG were detected along the seminiferous tubular wall. Moreover, the same pattern of immunofluorescence was observed when the IgG eluted from the testes of the immunized rats was layered on sections of normal rat testis. Circulating antibodies to STBM were detected using passive haemagglutination in approximately 45% of the immunized rats, with titers ranging from 1:20 to 1:80. Leukocyte migration was inhibited when the spleen cells of the immunized rats were incubated with antigens from the basement membrane of seminiferous tubules, whilst a negative reaction was obtained when the soluble fraction of testis homogenate was used. PMID:7050376

  11. Mechanisms of adaptation to chronic respiratory acidosis in the rabbit proximal tubule.

    PubMed Central

    Krapf, R

    1989-01-01

    The hyperbicarbonatemia of chronic respiratory acidosis is maintained by enhanced bicarbonate reabsorption in the proximal tubule. To investigate the cellular mechanisms involved in this adaptation, cell and luminal pH were measured microfluorometrically using (2",7')-bis(carboxyethyl)-(5,6)-carboxyfluorescein in isolated, microperfused S2 proximal convoluted tubules from control and acidotic rabbits. Chronic respiratory acidosis was induced by exposure to 10% CO2 for 52-56 h. Tubules from acidotic rabbits had a significantly lower luminal pH after 1-mm perfused length (7.03 +/- 0.09 vs. 7.26 +/- 0.06 in controls, perfusion rate = 10 nl/min). Chronic respiratory acidosis increased the initial rate of cell acidification (dpHi/dt) in response to luminal sodium removal by 63% and in response to lowering luminal pH (7.4-6.8) by 69%. Chronic respiratory acidosis also increased dpHi/dt in response to peritubular sodium removal by 63% and in response to lowering peritubular pH by 73%. In conclusion, chronic respiratory acidosis induces a parallel increase in the rates of the luminal Na/H antiporter and the basolateral Na/(HCO3)3 cotransporter. Therefore, the enhanced proximal tubule reabsorption of bicarbonate in chronic respiratory acidosis may be, at least in part, mediated by a parallel adaptation of these transporters. PMID:2537851

  12. Evaluation of the Diode laser (810nm,980nm) on dentin tubule diameter following internal bleaching

    PubMed Central

    Kiomarsi, Nazanin; Salim, Soheil; Sarraf, Pegah; Javad-Kharazifard, Mohammad

    2016-01-01

    Background The aim of this study was to evaluate the effect of diode laser irradiation and bleaching materials on the dentinal tubule diameter after laser bleaching. Material and Methods The dentin discs of 40 extracted third molar were used in this experiment. Each disc surface was divided into two halves by grooving. Half of samples were laser bleached at different wavelengths with two different concentrations of hydrogen peroxide. Other half of each disc with no laser bleaching remained as a negative control. Dentin discs were assigned randomly into four groups (n=10) with following hydrogen peroxide and diode laser wavelength specifications; Group 1 (30% - 810 nm), group 2 (30% - 980 nm), group 3 (46% - 810 nm) and group 4 (46% - 980 nm). All specimens were sent for scanning electron microscopic (SEM) analysis in order to measure tubular diameter in laser treated and control halves. Data were analyzed by ANOVA and Tukey test (p<0.05). Results A significant reduction in dentin tubule diameter was observed in groups 1, 2 and 4. There was no significant difference between groups 1 and 2 and between groups 3 and 4 after bleaching. Conclusions The SEM results showed that diode laser was able to reduce dentin tubule diameter and its effect on dentin was dependent on chemical action of bleaching material. Key words:Laser, diode, dentin, tubule, diameter. PMID:27398172

  13. Number and distribution of sperm-storage tubules in four strains of broiler breeders

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Restricted to the utero-vaginal junction (UVJ) in the hen's oviduct are tubular invaginations of the surface epithelium collectively referred to as the sperm-storage tubules (SSTs). One would expect that a larger number of SSTs would be positively correlated with longer, sustained fertility. However...

  14. ADH-PGE2 interactions in cortical collecting tubule. II. inhibition of Ca and P reabsorption.

    PubMed

    Holt, W F; Lechene, C

    1981-10-01

    In the absence of ADH, microperfused cortical collecting tubules of rabbits reabsorb calcium and phosphorus. Antidiuretic hormone (ADH) (200 microunits/ml Pitressin or synthetic arginine vasopressin) inhibits the reabsorption and may promote the secretion of calcium and phosphorus. At 5 min after incubation with ADH, there was a transitory increase in the potential difference and the reabsorption of sodium. The fluxes of calcium and phosphorus, however, showed no significant change from the control values. At 30-50 min after treatment with ADH, the reabsorption of calcium and phosphorus was inhibited and in some tubules calcium and phosphorus were secreted. The removal of vasopressin from the bath or the addition of 10(-5) M meclofenamate in vitro prevented ADH from inhibiting the reabsorption of calcium and phosphorus. Treatment of tubules with 10(-5) M prostaglandin E2 (PGE2) subsequent to incubation in a medium containing ADH and meclofenamate inhibited the reabsorption or even promoted the secretin of calcium and phosphorus, as did the prolonged incubation with ADH alone. We conclude that cortical collecting tubules reabsorb calcium and phosphorus in the absence of vasopressin and that ADH inhibits calcium and phosphorus reabsorption. Endogenous synthesis of PGE2 may mediate the inhibitory action of ADH, since meclofenamate (an inhibitor of the synthesis of prostaglandins) opposes and exogenous PGE2 mimics ADH. PMID:6947697

  15. Adaptive optics imaging of the outer retinal tubules in Bietti's crystalline dystrophy.

    PubMed

    Battu, R; Akkali, M C; Bhanushali, D; Srinivasan, P; Shetty, R; Berendschot, T T J M; Schouten, J S A G; Webers, C A

    2016-05-01

    PurposeTo study the outer retinal tubules using spectral domain optical coherence tomography and adaptive optics and in patients with Bietti's crystalline dystrophy.MethodsTen eyes of five subjects from five independent families with Bietti's crystalline Dystrophy (BCD) were characterized with best-corrected visual acuity (BCVA), full-field electroretinography, and fundus autofluorescence (FAF). High-resolution images were obtained with the spectral domain optical coherence tomography (SD-OCT) and adaptive optics (AO).ResultsSD-OCT showed prominent outer retinal layer loss and outer retinal tubulations at the margin of outer retinal loss. AO images displayed prominent macrotubules and microtubules with characteristic features in eight out of the 10 eyes. Crystals were present in all ten eyes. There was a reduction in the cone count in all eyes in the area outside the outer retinal tubules (ORT).ConclusionsThis study describes the morphology of the outer retinal tubules when imaged enface on the adaptive optics in patients with BCD. These findings provide insight into the macular structure of these patients. This may have prognostic implications and refine the study on the pathogenesis of BCD. PMID:26915747

  16. Micropuncture study of hypertonic mannitol diuresis in the proximal and distal tubule of the dog kidney

    PubMed Central

    Seely, John F.; Dirks, John H.

    1969-01-01

    Fractional reabsorption of water, sodium, and potassium at proximal and distal tubular sites within the nephron was studied by recollection-micropuncture experiments on dogs undergoing hypertonic mannitol diuresis. After an initial control hydropenic phase, 16% mannitol in modified Ringer's solution was administered intravenously, resulting in marked increases in fractional excretion of water (28.7%), sodium (12.6%), and potassium (63.9%). Inulin clearance decreased significantly from 35.1 to 25.2 ml/min. Analysis of paired micropuncture data revealed a significant decrease in tubule fluid to plasma (TF:P) inulin ratios in both the proximal tubule (1.63-1.45) and distal tubule (5.38-1.94). There was also a significant decrease in proximal TF:P sodium ratios (0.99-0.93) and potassium ratios (1.05-0.98). Distal TF:P sodium ratios, in contrast, rose significantly (0.38-0.59), while TF:P potassium ratios tended towards unity whether initially greater or less than one. Fractional reabsorption of sodium and water decreased by 5% and 10% respectively in the proximal tubule, but to a lesser extent than the resulting increases in fractional urinary excretion. The nonreabsorbed fraction, however, had increased sharply at the point of distal puncture for water (32%), sodium (26%), and potassium (26%), indicating a large inhibitory effect within the loop of Henle in addition to the smaller proximal effects. PMID:5355344

  17. Altered distribution of ICa impairs Ca release at the t-tubules of ventricular myocytes from failing hearts

    PubMed Central

    Bryant, Simon M.; Kong, Cherrie H.T.; Watson, Judy; Cannell, Mark B.; James, Andrew F.; Orchard, Clive H.

    2015-01-01

    In mammalian cardiac ventricular myocytes, Ca influx and release occur predominantly at t-tubules, ensuring synchronous Ca release throughout the cell. Heart failure is associated with disrupted t-tubule structure, but its effect on t-tubule function is less clear. We therefore investigated Ca influx and release at the t-tubules of ventricular myocytes isolated from rat hearts ~ 18 weeks after coronary artery ligation (CAL) or corresponding Sham operation. L-type Ca current (ICa) was recorded using the whole-cell voltage-clamp technique in intact and detubulated myocytes; Ca release at t-tubules was monitored using confocal microscopy with voltage- and Ca-sensitive fluorophores. CAL was associated with cardiac and cellular hypertrophy, decreased ejection fraction, disruption of t-tubule structure and a smaller, slower Ca transient, but no change in ryanodine receptor distribution, L-type Ca channel expression, or ICa density. In Sham myocytes, ICa was located predominantly at the t-tubules, while in CAL myocytes, it was uniformly distributed between the t-tubule and surface membranes. Inhibition of protein kinase A with H-89 caused a greater decrease of t-tubular ICa in CAL than in Sham myocytes; in the presence of H-89, t-tubular ICa density was smaller in CAL than in Sham myocytes. The smaller t-tubular ICa in CAL myocytes was accompanied by increased latency and heterogeneity of SR Ca release at t-tubules, which could be mimicked by decreasing ICa using nifedipine. These data show that CAL decreases t-tubular ICa via a PKA-independent mechanism, thereby impairing Ca release at t-tubules and contributing to the altered excitation–contraction coupling observed in heart failure. PMID:26103619

  18. Altered distribution of ICa impairs Ca release at the t-tubules of ventricular myocytes from failing hearts.

    PubMed

    Bryant, Simon M; Kong, Cherrie H T; Watson, Judy; Cannell, Mark B; James, Andrew F; Orchard, Clive H

    2015-09-01

    In mammalian cardiac ventricular myocytes, Ca influx and release occur predominantly at t-tubules, ensuring synchronous Ca release throughout the cell. Heart failure is associated with disrupted t-tubule structure, but its effect on t-tubule function is less clear. We therefore investigated Ca influx and release at the t-tubules of ventricular myocytes isolated from rat hearts ~18weeks after coronary artery ligation (CAL) or corresponding Sham operation. L-type Ca current (ICa) was recorded using the whole-cell voltage-clamp technique in intact and detubulated myocytes; Ca release at t-tubules was monitored using confocal microscopy with voltage- and Ca-sensitive fluorophores. CAL was associated with cardiac and cellular hypertrophy, decreased ejection fraction, disruption of t-tubule structure and a smaller, slower Ca transient, but no change in ryanodine receptor distribution, L-type Ca channel expression, or ICa density. In Sham myocytes, ICa was located predominantly at the t-tubules, while in CAL myocytes, it was uniformly distributed between the t-tubule and surface membranes. Inhibition of protein kinase A with H-89 caused a greater decrease of t-tubular ICa in CAL than in Sham myocytes; in the presence of H-89, t-tubular ICa density was smaller in CAL than in Sham myocytes. The smaller t-tubular ICa in CAL myocytes was accompanied by increased latency and heterogeneity of SR Ca release at t-tubules, which could be mimicked by decreasing ICa using nifedipine. These data show that CAL decreases t-tubular ICa via a PKA-independent mechanism, thereby impairing Ca release at t-tubules and contributing to the altered excitation-contraction coupling observed in heart failure. PMID:26103619

  19. Insect-specific flaviviruses in Aedes mosquitoes in Greece.

    PubMed

    Papa, Anna; Papadopoulou, Elpida; Paliwal, Ravish; Kalaitzopoulou, Stella; Mourelatos, Spiros; Niedrig, Matthias

    2016-08-01

    Mosquitoes of the genus Aedes are known vectors of pathogenic flaviviruses, and insect-specific flaviviruses (ISFs) have been detected in members of this genus in numerous parts of the world. In order to gain insight into whether Aedes mosquitoes in Greece are infected by flaviviruses, 1173 Aedes spp. mosquitoes collected in 2010 and 2012 were grouped in 53 pools and tested by RT nested PCR using flavivirus generic primers. Eight pools (15.09 %) were found to be PCR positive: five pools (5/53, 9.4 %) contained RNA sequences related to Ochlerotatus caspius flavivirus (OCFV), an ISF previously detected in the Iberian peninsula, two pools (2/53, 3.8 %) contained sequences related to a mosquito flavivirus detected in Aedes vexans (AeveV) in Italy and the Czech Republic, and one pool contained a DNA sequence that was too short to identify accurately. The highest OCFV prevalence (12.9 %) was observed in August 2010 in the regional unit of Thessaloniki. Similar sequences were later obtained from two Culex spp. pools collected in 2013 in the same regions. A genetic difference of 0.2-1.4 % was seen among the Greek OCFV strains, which differed by 2.2-4.1 % from the Iberian strains and by 6.2-11.1 % from the Finnish Hanko virus. The genetic distances among strains varied depending on the genome region (genes for E, NS3 and NS5 proteins), with NS3 being the most variable. The present study shows no evidence of infection of Aedes mosquitoes with known pathogenic flaviviruses, but it expands the geographic distribution of OCFV in the eastern Mediterranean area. Any implication of ISFs for public health (either directly or through interactions with other flaviviruses in the mosquitoes) remains to be elucidated. PMID:27198866

  20. Truck-mounted area-wide application of pyriproxyfen targeting Aedes aegypti and Aedes albopictus in northeast Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to determine the efficacy of truck-mounted ULV applications of pyriproxyfen against Aedes aegypti larvae in artificial water containers and wild adult Ae. albopictus populations in an urban setting. The study was conducted over a 3 ½ month period (Jun – Oct 2012), during wh...

  1. Early effects of uranyl nitrate on respiration and K sup + transport in rabbit proximal tubule

    SciTech Connect

    Brady, H.R.; Kone, B.C.; Brenner, R.M.; Gullans, S.R. )

    1989-07-01

    The mechanisms by which uranyl nitrate (UN) is toxic to the proximal tubule are incompletely understood. To define these further we studied potassium (K+) transport and oxygen consumption (QO2) in rabbit proximal tubule suspensions in vitro immediately after exposure to UN using extracellular O2- and K+-sensitive electrodes. UN caused a cumulative dose-dependent inhibition of proximal tubule QO2, with a threshold concentration of 5 x 10(-5) M. Kinetic analysis suggested two patterns of cell injury: a higher affinity inhibition of QO2 with a Ki of 5 x 10(-4) M, and a lower affinity inhibition of QO2 with a Ki of 10 mM. QO2 was studied in detail in the presence of these Ki concentrations of UN to define the initial cellular events. The results indicated that different cellular processes displayed different sensitivities to UN. At submillimolar concentrations UN caused progressive selective inhibition of ouabain-insensitive QO2 (15% inhibition at 2 minutes). Ouabain-sensitive QO2 and nystatin-stimulated QO2 were not affected, suggesting that Na+,K+-ATPase activity and its coupling to mitochondrial ATP synthesis were intact. Direct measurement of proximal tubule net K+ flux confirmed that Na+,K+-ATPase activity was unchanged. Similarly, UN did not inhibit basal (state 4) or ADP-stimulated (state 3) mitochondrial QO2 in digitonin-permeabilized tubules, confirming that the mitochondria were intact. In contrast, higher concentrations of UN (greater than or equal to 1 mM) caused rapid inhibition of QO2 and net K+ efflux, due to inhibition of Na+,K+-ATPase activity and mitochondrial injury.

  2. Caveolin-1 Induces Formation of Membrane Tubules That Sense Actomyosin Tension and Are Inhibited by Polymerase I and Transcript Release Factor/Cavin-1

    PubMed Central

    Verma, Prakhar; Ostermeyer-Fay, Anne G.

    2010-01-01

    Caveolin-1 and caveolae are often lost in cancer. We found that levels of caveolin-1 and polymerase I and transcript release factor (PTRF)/cavin-1 correlated closely in a panel of cancer and normal cells. Caveolin-1 reexpression in cancer cells lacking both proteins induced formation of long membrane tubules rarely seen in normal cells. PTRF/cavin-1 inhibited tubule formation when coexpressed with caveolin-1 in these cells, whereas suppression of PTRF/cavin-1 expression in cells that normally expressed both genes stimulated tubule formation by endogenous caveolin-1. Caveolin-1 tubules shared several features with previously described Rab8 tubules. Coexpressed Rab8 and caveolin-1 labeled the same tubules (as did EHD proteins), and synergized to promote tubule formation, whereas a dominant-interfering Rab8 mutant inhibited caveolin-1 tubule formation. Both overexpression and inhibition of dynamin-2 reduced the abundance of caveolin-1 tubules. Caveolin-1 reexpression in SK-BR-3 breast cancer cells also induced formation of short membrane tubules close to cortical actin filaments, which required actin filaments but not microtubules. Actomyosin-induced tension destabilized both long and short tubules; they often snapped and resolved to small vesicles. Actin filament depolymerization or myosin II inhibition reduced tension and stabilized tubules. These data demonstrate a new function for PTRF/cavin-1, a new functional interaction between caveolin-1 and Rab8 and that actomyosin interactions can induce tension on caveolin-1-containing membranes. PMID:20427576

  3. Dentin hypersensitivity treatment by CO2 laser: the influence of the density of dentin tubules and laser-beam incidence

    NASA Astrophysics Data System (ADS)

    Colojoara, Carmen; Gabay, Shimon; van der Meulen, Freerk W.; van Gemert, Martin J. C.; Miron, Mariana I.; Mavrantoni, Androniki

    1997-12-01

    Dentin hypersensitivity is considered to be a consequence of the presence of open dentin tubules on the exposed dentin surface. Various methods and materials used in the treatment of this disease are directed to achieve a tubule's occlusion. The purpose of this study was to evaluate under scanning electron microscopy and clinical method the sealing effects of CO2 laser on dentin tubules of human teeth without any damages of the surrounding tissues. Samples of freshly extracted noncarious 3rd molars were used. The teeth were randomly divided in to two groups A and B. The samples of group A were exposed to laser beam in cervical area, directed parallel to their dentin tubules. The teeth of group B were sectioned through a hypothetical carious lesion and lased perpendicularly or obliquely of the dentin tubules. The CO2 laser, at 10.6 micrometers wavelength, was operated only in pulse mode and provided 6.25 - 350 mJ in a burst of 25 pulses each of 250 microsecond(s) time duration with a 2 ms time interval between successive pulses (repetition rate up to 500 mH). Melting of dentin surface and partial closure of exposed dentin tubules were found for all specimens at 6.25 to 31.25 mJ energy. Our results indicated that using CO2 laser in a parallel orientation of laser beam with dentin tubules, the dentin sensitivity can be reduced without any damages of pulp vitality.

  4. Sildenafil ameliorates left ventricular T-tubule remodeling in a pressure overload-induced murine heart failure model

    PubMed Central

    Huang, Chun-kai; Chen, Bi-yi; Guo, Ang; Chen, Rong; Zhu, Yan-qi; Kutschke, William; Hong, Jiang; Song, Long-sheng

    2016-01-01

    Aim: Sildenafil, a phosphodiesterase 5 (PDE5) inhibitor, has been shown to exert beneficial effects in heart failure. The purpose of this study was to test whether sildenafil suppressed transverse-tubule (T-tubule) remodeling in left ventricular (LV) failure and thereby providing the therapeutic benefits. Methods: A pressure overload-induced murine heart failure model was established in mice by thoracic aortic banding (TAB). One day after TAB, the mice received sildenafil (100 mg·kg−1·d−1, sc) or saline for 5 weeks. At the end of treatment, echocardiography was used to examine LV function. Then the intact hearts were dissected out and placed in Langendorff-perfusion chamber for in situ confocal imaging of T-tubule ultrastructure from epicardial myocytes. Results: TAB surgery resulted in heart failure accompanied by remarkable T-tubule remodeling. Sildenafil treatment significantly attenuated TAB-induced cardiac hypertrophy and congestive heart failure, improved LV contractile function, and preserved T-tubule integrity in LV cardiomyocytes. But sildenafil treatment did not significantly affect the chamber dilation. The integrity of LV T-tubule structure was correlated with cardiac hypertrophy (R2=0.74, P<0.01) and global LV function (R2=0.47, P<0.01). Conclusion: Sildenafil effectively ameliorates LV T-tubule remodeling in TAB mice, revealing a novel mechanism underlying the therapeutic benefits of sildenafil in heart failure. PMID:26972492

  5. Comparative evaluation of NovaMin desensitizer and Gluma desensitizer on dentinal tubule occlusion: a scanning electron microscopic study

    PubMed Central

    Joshi, Surabhi; Gowda, Ashwini Shivananje

    2013-01-01

    Purpose In this study, the effect of calcium sodium phosphosilicate (NovaMin) desensitizing agent, which is a powder-based system, and hydroxyethyl methacrylate and glutaraldehyde (Gluma desensitizer), which is liquid-based system, on dentinal tubule occlusion was analyzed by scanning electron microscope. The effects of the above two along with one control group were compared to determine the more effective method of sealing the dentinal tubules after initial application. Methods Twenty specimens were allocated to each of 3 groups: Control, Gluma desensitizer, and NovaMin. Two additional samples were also prepared and treated with Gluma and NovaMin; these samples were longitudinally fractured. The specimens were prepared from extracted sound human premolars and were stored in 10% formalin at room temperature. The teeth were cleaned of gross debris and then sectioned to provide one to two dentin specimens. The dentin specimens were etched with 6% citric acid for 2 minutes and rinsed in distilled water. Control discs were dried, and the test discs were treated with the desensitizing agents as per the manufacturer's instructions. The discs as well as longitudinal sections were later analyzed under the scanning electron microscope. The proportions of completely occluded, partially occluded, and open tubules within each group were calculated. The ratios of completely and partially occluded tubules to the total tubules for all the groups was determined, and the data was statistically analyzed using nonparametric tests and statistical significance was calculated. Results NovaMin showed more completely occluded tubules (0.545±0.051) while Gluma desensitizer showed more partially occluded tubules (0.532±0.075). The differences among all the groups were statistically significant (P≤ 0.05). Conclusion Both materials were effective in occluding dentinal tubules but NovaMin appeared more promising in occluding tubules completely after initial application. PMID:24455439

  6. Biogeography of the two major arbovirus mosquito vectors, Aedes aegypti and Aedes albopictus (Diptera, Culicidae), in Madagascar

    PubMed Central

    2012-01-01

    Background In the past ten years, the Indian Ocean region has been the theatre of severe epidemics of chikungunya and dengue. These outbreaks coincided with a high increase in populations of Aedes albopictus that outcompete its sister taxon Aedes aegypti in most islands sampled. The objective of this work was to update the entomological survey of the two Aedes species in the island of Madagascar which has to face these arboviroses. Methods The sampling of Aedes mosquitoes was conducted during two years, from October 2007 to October 2009, in fifteen localities from eight regions of contrasting climates. Captured adults were identified immediately whereas immature stages were bred until adult stage for determination. Phylogenetic analysis was performed using two mtDNA genes, COI and ND5 and trees were constructed by the maximum likelihood (ML) method with the gene time reversible (GTR) model. Experimental infections with the chikungunya virus strain 06.21 at a titer of 107.5 pfu/mL were performed to evaluate the vector competence of field-collected mosquitoes. Disseminated infection rates were measured fourteen days after infection by immunofluorescence assay performed on head squashes. Results The species Aedes aegypti was detected in only six sites in native forests and natural reserves. In contrast, the species Aedes albopictus was found in 13 out of the 15 sites sampled. Breeding sites were mostly found in man-made environments such as discarded containers, used tires, abandoned buckets, coconuts, and bamboo cuts. Linear regression models showed that the abundance of Ae. albopictus was significantly influenced by the sampling region (F = 62.00, p < 2.2 × 10-16) and period (F = 36.22, p = 2.548 × 10-13), that are associated with ecological and climate variations. Phylogenetic analysis of the invasive Ae. albopictus distinguished haplotypes from South Asia and South America from those of Madagascar, but the markers used were not discriminant enough to discern

  7. Identification of germline transcriptional regulatory elements in Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Akbari, Omar S.; Papathanos, Philippos A.; Sandler, Jeremy E.; Kennedy, Katie; Hay, Bruce A.

    2014-02-01

    The mosquito Aedes aegypti is the principal vector for the yellow fever and dengue viruses, and is also responsible for recent outbreaks of the alphavirus chikungunya. Vector control strategies utilizing engineered gene drive systems are being developed as a means of replacing wild, pathogen transmitting mosquitoes with individuals refractory to disease transmission, or bringing about population suppression. Several of these systems, including Medea, UDMEL, and site-specific nucleases, which can be used to drive genes into populations or bring about population suppression, utilize transcriptional regulatory elements that drive germline-specific expression. Here we report the identification of multiple regulatory elements able to drive gene expression specifically in the female germline, or in the male and female germline, in the mosquito Aedes aegypti. These elements can also be used as tools with which to probe the roles of specific genes in germline function and in the early embryo, through overexpression or RNA interference.

  8. EFFICACY OF THAI NEEM OIL AGAINST AEDES AEGYPTI (L.) LARVAE.

    PubMed

    Silapanuntakul, Suthep; Keanjoom, Romnalin; Pandii, Wongdyan; Boonchuen, Supawadee; Sombatsiri, Kwanchai

    2016-05-01

    Trees with larvicidal activity may be found in Thailand. We conducted this study to evaluate the efficacy and length of efficacy of Thai neem (Azadirachta siamensis) oil emulsion and an alginate bead of Thai neem oil formulation against early fourth stage Aedes aegypti larvae using a dipping test. The Thai neem oil emulsion had significantly greater larvicidal activity than the alginate bead formulation at 12 to 60 hours post-exposure (p < 0.01). The Thai neem oil formulation resulted in 100% mortality among the early fourth stage Aedes aegypti larvae at 48 hours, while the alginate bead formulation resulted in 98% larval mortality at 84 hours and 100% mortality at 96 hours. The mean larval mortality using the Thai neem oil emulsion dropped to < 25% by 12 days and with the alginate beads dropped to < 25% by 15 days of exposure. PMID:27405123

  9. Proteomic Identification of Dengue Virus Binding Proteins in Aedes aegypti Mosquitoes and Aedes albopictus Cells

    PubMed Central

    Muñoz, Maria de Lourdes; Limón-Camacho, Gustavo; Tovar, Rosalinda; Diaz-Badillo, Alvaro; Mendoza-Hernández, Guillermo; Black, William C.

    2013-01-01

    The main vector of dengue in America is the mosquito Aedes aegypti, which is infected by dengue virus (DENV) through receptors of midgut epithelial cells. The envelope protein (E) of dengue virus binds to receptors present on the host cells through its domain III that has been primarily recognized to bind cell receptors. In order to identify potential receptors, proteins from mosquito midgut tissue and C6/36 cells were purified by affinity using columns with the recombinant E protein domain III (rE-DIII) or DENV particles bound covalently to Sepharose 4B to compare and evaluate their performance to bind proteins including putative receptors from female mosquitoes of Ae. aegypti. To determine their identity mass spectrometric analysis of purified proteins separated by polyacrylamide gel electrophoresis was performed. Our results indicate that both viral particles and rE-DIII bound proteins with the same apparent molecular weights of 57 and 67 kDa. In addition, viral particles bound high molecular weight proteins. Purified proteins identified were enolase, beta-adrenergic receptor kinase (beta-ARK), translation elongation factor EF-1 alpha/Tu, and cadherin. PMID:24324976

  10. Immunohistochemical demonstration of exocytosis-regulating proteins within rat molar dentinal tubules.

    PubMed

    Norlin, T; Hilliges, M; Brodin, L

    1999-03-01

    No morphologically defined synaptic structures have so far been detected between nerve terminals and the dentine-producing odontoblasts. Recent studies of the molecular mechanisms in neuronal exocytosis have identified several proteins that participate in synaptic-vesicle exocytosis. By localizing these proteins with immunohistochemical methods, information about the capacity for synaptic exocytosis should be obtained. Here, antibodies directed against some of the exocytosis-related proteins were used to investigate whether they are present in nerve fibers within the dentinal tubules in rat molars. Antibodies against synaptosome-associated protein of 25 kDa, Rab 3, synaptotagmin and synapsin all produced a punctuate staining pattern, suggesting that the proteins are accumulated in bouton-like elements. The results demonstrate that a set of exocytosis-related proteins is accumulated in the dentinal tubules, most probably within the intradentinal nerves. This finding is consistent with the hypothesis that intradentinal nerves can mediate efferent signals. PMID:10217513

  11. Peutz-Jeghers syndrome with ovarian sex cord tumor with annular tubules and cervical adenoma malignum.

    PubMed

    Podczaski, E; Kaminski, P F; Pees, R C; Singapuri, K; Sorosky, J I

    1991-07-01

    A patient with Peutz-Jeghers syndrome, a sex cord tumor with annular tubules, and an initially unrecognized adenoma malignum of the cervix is described. The patient presented with a mucinous adenocarcinoma in the vaginal apex. Review of the hysterectomy slides demonstrated an adenoma malignum of the cervix. In addition to a microscopic sex cord tumor with annular tubules of the right ovary, the left ovary contained mucinous cystadenomas. Adenoma malignum remains a difficult diagnosis and is frequently made only after hysterectomy for a presumed benign indication; pathology frequently demonstrates a deeply invasive, unusually well-differentiated adenocarcinoma of the cervix. Patients with Peutz-Jeghers syndrome need careful clinical and cytologic follow-up to exclude such lesions. PMID:1916514

  12. Facilitation of Endosomal Recycling by an IRG Protein Homolog Maintains Apical Tubule Structure in Caenorhabditis elegans.

    PubMed

    Grussendorf, Kelly A; Trezza, Christopher J; Salem, Alexander T; Al-Hashimi, Hikmat; Mattingly, Brendan C; Kampmeyer, Drew E; Khan, Liakot A; Hall, David H; Göbel, Verena; Ackley, Brian D; Buechner, Matthew

    2016-08-01

    Determination of luminal diameter is critical to the function of small single-celled tubes. A series of EXC proteins, including EXC-1, prevent swelling of the tubular excretory canals in Caenorhabditis elegans In this study, cloning of exc-1 reveals it to encode a homolog of mammalian IRG proteins, which play roles in immune response and autophagy and are associated with Crohn's disease. Mutants in exc-1 accumulate early endosomes, lack recycling endosomes, and exhibit abnormal apical cytoskeletal structure in regions of enlarged tubules. EXC-1 interacts genetically with two other EXC proteins that also affect endosomal trafficking. In yeast two-hybrid assays, wild-type and putative constitutively active EXC-1 binds to the LIM-domain protein EXC-9, whose homolog, cysteine-rich intestinal protein, is enriched in mammalian intestine. These results suggest a model for IRG function in forming and maintaining apical tubule structure via regulation of endosomal recycling. PMID:27334269

  13. Tubulation by amphiphysin requires concentration-dependent switching from wedging to scaffolding

    PubMed Central

    Isas, J. Mario; Ambroso, Mark R.; Hegde, Prabhavati B.; Langen, Jennifer; Langen, Ralf

    2015-01-01

    Summary BAR proteins are involved in a variety of membrane remodeling events, but how they can mold membranes into different shapes remains poorly understood. Using EPR, we find that vesicle binding of the N-BAR protein amphiphysin is predominantly mediated by the shallow insertion of amphipathic N-terminal helices. In contrast, the interaction with tubes involves deeply inserted N-terminal helices together with the concave surface of the BAR domain, which acts as a scaffold. Combined with the observed concentration dependence of tubulation and BAR domain scaffolding, the data indicate that initial membrane deformations and vesicle binding are mediated by insertion of amphipathic helical wedges, while tubulation requires high protein densities at which oligomeric BAR domain scaffolds form. In addition, we identify a pocket of residues on the concave surface of the BAR domain that deeply insert into tube membrane. Interestingly, this pocket harbors a number of disease mutants in the homologous amphiphysin 2. PMID:25865245

  14. Membrane stress causes inhibition of water channels in brush border membrane vesicles from kidney proximal tubule.

    PubMed

    Soveral, G; Macey, R I; Moura, T F

    1997-08-01

    Brush border membrane vesicles (BBMV) from rabbit kidney proximal tubule cells, prepared with different internal solute concentrations (cellobiose buffer 13, 18 or 85 mosM) developed an hydrostatic pressure difference across the membrane of 18.7 mosM, that causes a membrane tension close to 5 x 10(-5) N cm-1. When subjected to several hypertonic osmotic shocks an initial delay of osmotic shrinkage (a lag time), corresponding to a very small change in initial volume was apparent. This initial osmotic response, which is significantly retarded, was correlated with the initial period of elevated membrane tension, suggesting that the water permeability coefficient is inhibited by membrane stress. We speculate that this inhibition may serve to regulate cell volume in the proximal tubule. PMID:9468597

  15. Field evaluation of Bacillus thuringiensis H-14 against Aedes mosquitoes.

    PubMed

    Lee, Y W; Zairi, J

    2006-06-01

    Studies were carried out on the residual efficacy of Bacillus thuringiensis H-14 (water dispersible granule, VectoBac ABG 6511) as direct application in the control of Aedes larvae in the field. Field Aedes sp populations in the earthen and glass jars were predetermined before initiation of the trial. On confirmation of the presence of Aedes species in the designated area, Sungai Nibong Kecil, Penang Island, Malaysia, Bti was introduced in the 55L earthen and 3L glass jars). Two test designs were carried out. The first design had treated water replenished daily with 6L of seasoned water and the second design is without the replenishment of water but evaporated water was replenished. Bti was effective in the field for at least 35 days with more than 80% reduction in the Aedes larvae in the treated containers. For earthen jars with daily replenishment of water, 100% reduction was recorded for the first 3 days, while more than 80% reduction was recorded up to day 40. At day 60, Bti still provided an efficacy of 54.32 +/- 4.61 (%) of reduction. Whilst for earthen jars without daily replenishment of water, 100% reduction was recorded for the first 5 days, while more than 80% of reduction was recorded up to day 40. For the glass jars studied, similar efficacy was observed. In jars with daily replenishment of water a better larval control was observed. Percentage of reduction from day 50 to 60 for replenishment of water was between 50 to 70% compared to without replenishment of water with less than 40%. PMID:17041550

  16. Intraspecific Competition and Population Dynamics of Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Paixão, C. A.; Charret, I. C.; Lima, R. R.

    2012-04-01

    We report computational simulations for the evolution of the population of the dengue vector, Aedes aegypti mosquitoes. The results suggest that controlling the mosquito population, on the basis of intraspecific competition at the larval stage, can be an efficient mechanism for controlling the spread of the epidemic. The results also show the presence of a kind of genetic evolution in vector population, which results mainly in increasing the average lifespan of individuals in adulthood.

  17. First record of Aedes (Stegomyia) albopictus in Belgium.

    PubMed

    Schaffner, Francis; Van Bortel, Wim; Coosemans, Marc

    2004-06-01

    The 1st record of Aedes albopictus in Belgium was made in a village in Oost-Vlaanderen Province. Two preimaginal stages were collected on October 31, 2000, in the used tire stock of a recycling company that imports tires from the USA and Japan. The species has reproduced on site, and local environmental conditions make its establishment possible. Anopheles plumbeus was a common companion species found in tires in high densities. PMID:15264633

  18. Similarity solutions for systems arising from an Aedes aegypti model

    NASA Astrophysics Data System (ADS)

    Freire, Igor Leite; Torrisi, Mariano

    2014-04-01

    In a recent paper a new model for the Aedes aegypti mosquito dispersal dynamics was proposed and its Lie point symmetries were investigated. According to the carried group classification, the maximal symmetry Lie algebra of the nonlinear cases is reached whenever the advection term vanishes. In this work we analyze the family of systems obtained when the wind effects on the proposed model are neglected. Wide new classes of solutions to the systems under consideration are obtained.

  19. Angiotensin II Stimulation of DPP4 Activity Regulates Megalin in the Proximal Tubules.

    PubMed

    Aroor, Annayya; Zuberek, Marcin; Duta, Cornel; Meuth, Alex; Sowers, James R; Whaley-Connell, Adam; Nistala, Ravi

    2016-01-01

    Proteinuria is a marker of incipient kidney injury in many disorders, including obesity. Previously, we demonstrated that megalin, a receptor endocytotic protein in the proximal tubule, is downregulated in obese mice, which was prevented by inhibition of dipeptidyl protease 4 (DPP4). Obesity is thought to be associated with upregulation of intra-renal angiotensin II (Ang II) signaling via the Ang II Type 1 receptor (AT₁R) and Ang II suppresses megalin expression in proximal tubule cells in vitro. Therefore, we tested the hypothesis that Ang II will suppress megalin protein via activation of DPP4. We used Ang II (200 ng/kg/min) infusion in mice and Ang II (10(-8) M) treatment of T35OK-AT₁R proximal tubule cells to test our hypothesis. Ang II-infused mouse kidneys displayed increases in DPP4 activity and decreases in megalin. In proximal tubule cells, Ang II stimulated DPP4 activity concurrent with suppression of megalin. MK0626, a DPP4 inhibitor, partially restored megalin expression similar to U0126, a mitogen activated protein kinase (MAPK)/extracellular regulated kinase (ERK) kinase kinase (MEK) 1/2 inhibitor and AG1478, an epidermal growth factor receptor (EGFR) inhibitor. Similarly, Ang II-induced ERK phosphorylation was suppressed with MK0626 and Ang II-induced DPP4 activity was suppressed by U0126. Therefore, our study reveals a cross talk between AT₁R signaling and DPP4 activation in the regulation of megalin and underscores the significance of targeting DPP4 in the prevention of obesity related kidney injury progression. PMID:27213360

  20. Changes of myoid and endothelial cells in the peritubular wall during contraction of the seminiferous tubule.

    PubMed

    Losinno, Antonella D; Sorrivas, Viviana; Ezquer, Marcelo; Ezquer, Fernando; López, Luis A; Morales, Alfonsina

    2016-08-01

    The wall of the seminiferous tubule in rodents consists of an inner layer of myoid cells covered by an outer layer of endothelial cells. Myoid cells are a type of smooth muscle cell containing α-actin filaments arranged in two independent layers that contract when stimulated by endothelin-1. The irregular surface relief of the tubular wall is often considered a hallmark of contraction induced by a variety of stimuli. We examine morphological changes of the rat seminiferous tubule wall during contraction by a combination of light, confocal, transmission and scanning electron microscopy. During ET-1-induced contraction, myoid cells changed from a flat to a conical shape, but their actin filaments remained in independent layers. As a consequence of myoid cell contraction, the basement membrane became wavy, orientation of collagen fibers in the extracellular matrix was altered and the endothelial cell layer became folded. To observe the basement of the myoid cell cone, the endothelial cell monolayer was removed by collagenase digestion prior to SEM study. In contracted tubules, it is possible to distinguish cell relief: myoid cells have large folds on the external surface oriented parallel to the tubular axis, whereas endothelial cells have numerous cytoplasmic projections facing the interstitium. The myoid cell cytoskeleton is unusual in that the actin filaments are arranged in two orthogonal layers, which adopt differing shapes during contraction with myoid cells becoming cone-shaped. This arrangement impacts on other components of the seminiferous tubule wall and affects the propulsion of the tubular contents to the rete testis. PMID:26987820

  1. Proximal tubule-targeted heme oxygenase-1 in cisplatin-induced acute kidney injury.

    PubMed

    Bolisetty, Subhashini; Traylor, Amie; Joseph, Reny; Zarjou, Abolfazl; Agarwal, Anupam

    2016-03-01

    Heme oxygenase-1 (HO-1) is a cytoprotective enzyme that catalyzes the breakdown of heme to biliverdin, carbon monoxide, and iron. The beneficial effects of HO-1 expression are not merely due to degradation of the pro-oxidant heme but are also credited to the by-products that have potent, protective effects, including antioxidant, anti-inflammatory, and prosurvival properties. This is well reflected in the preclinical animal models of injury in both renal and nonrenal settings. However, excessive accumulation of the by-products can be deleterious and lead to mitochondrial toxicity and oxidative stress. Therefore, use of the HO system in alleviating injury merits a targeted approach. Based on the higher susceptibility of the proximal tubule segment of the nephron to injury, we generated transgenic mice using cre-lox technology to enable manipulation of HO-1 (deletion or overexpression) in a cell-specific manner. We demonstrate the validity and feasibility of these mice by breeding them with proximal tubule-specific Cre transgenic mice. Similar to previous reports using chemical modulators and global transgenic mice, we demonstrate that whereas deletion of HO-1, specifically in the proximal tubules, aggravates structural and functional damage during cisplatin nephrotoxicity, selective overexpression of HO-1 in proximal tubules is protective. At the cellular level, cleaved caspase-3 expression, a marker of apoptosis, and p38 signaling were modulated by HO-1. Use of these transgenic mice will aid in the evaluation of the effects of cell-specific HO-1 expression in response to injury and assist in the generation of targeted approaches that will enhance recovery with reduced, unwarranted adverse effects. PMID:26672618

  2. Passive permeability of salicylic acid in renal proximal S2 and S3 tubules

    SciTech Connect

    Chatton, J.Y.; Roch-Ramel, F. )

    1991-03-01

    The role of nonionic diffusion in the transport of salicylic acid across rabbit proximal S2 and S3 segments was investigated using the in vitro isolated perfused tubule technique. The ({sup 14}C) salicylic acid apparent reabsorptive permeability (P'I-b, 10(-5) cm/s) was measured at 19 degrees C with luminal solutions kept at different pH and bath maintained at pH 7.4. In S2 tubules, P'I-b was 25.0 +/- 3.5 when luminal pH was 6.0; P'I-b decreased to 8.1 +/- 1.4 and to 4.4 +/- 1.2 at a luminal pH of 6.5 and 7.0, respectively. In S3 tubules, P'I-b was 17.6 +/- 2.4, 5.3 +/- 1.1 and 3.4 +/- 1.1 at a luminal pH of 6.0, 6.5 and 7.0, respectively. There was a close correlation between P'I-b and the calculated proportion of nonionized salicylic acid present at each pH, indicating that only the nonionized molecule could diffuse in our conditions. We calculated the apparent permeability of nonionic salicylic acid and found 0.248 +/- 0.032 cm/s for S2 and 0.176 +/- 0.022 cm/s for S3 tubules. These calculated permeabilities were independent of pH.

  3. Angiotensin II Stimulation of DPP4 Activity Regulates Megalin in the Proximal Tubules

    PubMed Central

    Aroor, Annayya; Zuberek, Marcin; Duta, Cornel; Meuth, Alex; Sowers, James R.; Whaley-Connell, Adam; Nistala, Ravi

    2016-01-01

    Proteinuria is a marker of incipient kidney injury in many disorders, including obesity. Previously, we demonstrated that megalin, a receptor endocytotic protein in the proximal tubule, is downregulated in obese mice, which was prevented by inhibition of dipeptidyl protease 4 (DPP4). Obesity is thought to be associated with upregulation of intra-renal angiotensin II (Ang II) signaling via the Ang II Type 1 receptor (AT1R) and Ang II suppresses megalin expression in proximal tubule cells in vitro. Therefore, we tested the hypothesis that Ang II will suppress megalin protein via activation of DPP4. We used Ang II (200 ng/kg/min) infusion in mice and Ang II (10−8 M) treatment of T35OK-AT1R proximal tubule cells to test our hypothesis. Ang II-infused mouse kidneys displayed increases in DPP4 activity and decreases in megalin. In proximal tubule cells, Ang II stimulated DPP4 activity concurrent with suppression of megalin. MK0626, a DPP4 inhibitor, partially restored megalin expression similar to U0126, a mitogen activated protein kinase (MAPK)/extracellular regulated kinase (ERK) kinase kinase (MEK) 1/2 inhibitor and AG1478, an epidermal growth factor receptor (EGFR) inhibitor. Similarly, Ang II-induced ERK phosphorylation was suppressed with MK0626 and Ang II-induced DPP4 activity was suppressed by U0126. Therefore, our study reveals a cross talk between AT1R signaling and DPP4 activation in the regulation of megalin and underscores the significance of targeting DPP4 in the prevention of obesity related kidney injury progression. PMID:27213360

  4. Recent Updates on the Proximal Tubule Renin-Angiotensin System in Angiotensin II-Dependent Hypertension.

    PubMed

    Li, Xiao C; Zhuo, Jia L

    2016-08-01

    It is well recognized that the renin-angiotensin system (RAS) exists not only as circulating, paracrine (cell to cell), but also intracrine (intracellular) system. In the kidney, however, it is difficult to dissect the respective contributions of circulating RAS versus intrarenal RAS to the physiological regulation of proximal tubular Na(+) reabsorption and hypertension. Here, we review recent studies to provide an update in this research field with a focus on the proximal tubular RAS in angiotensin II (ANG II)-induced hypertension. Careful analysis of available evidence supports the hypothesis that both local synthesis or formation and AT1 (AT1a) receptor- and/or megalin-mediated uptake of angiotensinogen (AGT), ANG I and ANG II contribute to high levels of ANG II in the proximal tubules of the kidney. Under physiological conditions, nearly all major components of the RAS including AGT, prorenin, renin, ANG I, and ANG II would be filtered by the glomerulus and taken up by the proximal tubules. In ANG II-dependent hypertension, the expression of AGT, prorenin, and (pro)renin receptors, and angiotensin-converting enzyme (ACE) is upregulated rather than downregulated in the kidney. Furthermore, hypertension damages the glomerular filtration barrier, which augments the filtration of circulating AGT, prorenin, renin, ANG I, and ANG II and their uptake in the proximal tubules. Together, increased local ANG II formation and augmented uptake of circulating ANG II in the proximal tubules, via activation of AT1 (AT1a) receptors and Na(+)/H(+) exchanger 3, may provide a powerful feedforward mechanism for promoting Na(+) retention and the development of ANG II-induced hypertension. PMID:27372447

  5. Reduced proximal tubule angiotensin II receptor expression in streptozotocin-induced diabetes mellitus.

    PubMed

    Cheng, H F; Burns, K D; Harris, R C

    1994-12-01

    Diabetes mellitus is characterized by alterations in the intrarenal renin-angiotensin system, including decreases in glomerular angiotensin II (Ang II) receptor density. Since Ang II regulates proximal tubule transport function, the present studies examined whether diabetes altered expression of proximal tubule receptors. In basolateral membranes from 14 day streptozotocin-induced diabetic rats, specific binding of 125I Ang II was decreased to 53 +/- 8% of control (3.2 +/- 0.5 vs. 1.5 +/- 0.2 fmol/mg protein; N = 7; P < 0.02). Similarly, in proximal tubule brush border membranes from diabetic animals, specific binding was decreased to 63 +/- 11% of control (1.1 +/- 0.2 vs 0.6 +/- 0.1 fmol/mg protein; N = 9; P < 0.05). Concomitant insulin treatment reversed the decrease in specific binding of 125I Ang II to basolateral membranes (109 +/- 26% of control; N = 3) and to brush border membranes (85 +/- 17% of control; N = 6). In order to determine if changes in expression of type-1 Ang II receptors (AT1R) accompanied the changes in binding, quantitative polymerase chain reaction of AT1R mRNA was performed and expressed as the ratio of the amplified AT1R to that of an Msc1/Msc1 internal deletion mutant and normalized to that of beta-actin. In total RNA from proximal tubule suspensions of diabetic animals, AT1R mRNA expression decreased by 38% (21 +/- 3 vs. 13 +/- 2 cpm AT1R/cpm deletion mutant/cpm beta actin/10(6); N = 4; P < 0.0025). Insulin treatment reverted AT1R mRNA expression to control levels (22 +/- 3 cpm AT1R/cpm deletion mutant/cpm beta actin/10(6); P < 0.001 compared to the untreated group).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7700017

  6. Proximal tubule PPARα attenuates renal fibrosis and inflammation caused by unilateral ureteral obstruction

    PubMed Central

    Li, Shenyang; Mariappan, Nithya; Megyesi, Judit; Shank, Brian; Kannan, Krishnaswamy; Theus, Sue; Price, Peter M.; Duffield, Jeremy S.

    2013-01-01

    We examined the effects of increased expression of proximal tubule peroxisome proliferator-activated receptor (PPAR)α in a mouse model of renal fibrosis. After 5 days of unilateral ureteral obstruction (UUO), PPARα expression was significantly reduced in kidney tissue of wild-type mice but this downregulation was attenuated in proximal tubules of PPARα transgenic (Tg) mice. When compared with wild-type mice subjected to UUO, PPARα Tg mice had reduced mRNA and protein expression of proximal tubule transforming growth factor (TGF)-β1, with reduced production of extracellular matrix proteins including collagen 1, fibronectin, α-smooth muscle actin, and reduced tubulointerstitial fibrosis. UUO-mediated increased expression of microRNA 21 in kidney tissue was also reduced in PPARα Tg mice. Overexpression of PPARα in cultured proximal tubular cells by adenoviral transduction reduced aristolochic acid-mediated increased production of TGF-β, demonstrating PPARα signaling reduces epithelial TGF-β production. Flow cytometry studies of dissociated whole kidneys demonstrated reduced macrophage infiltration to kidney tissue in PPARα Tg mice after UUO. Increased expression of proinflammatory cytokines including IL-1β, IL-6, and TNF-α in wild-type mice was also significantly reduced in kidney tissue of PPARα Tg mice. In contrast, the expression of anti-inflammatory cytokines IL-10 and arginase-1 was significantly increased in kidney tissue of PPARα Tg mice when compared with wild-type mice subjected to UUO. Our studies demonstrate several mechanisms by which preserved expression of proximal tubule PPARα reduces tubulointerstitial fibrosis and inflammation associated with obstructive uropathy. PMID:23804447

  7. Poly(ADP-ribose) polymerase regulates glycolytic activity in kidney proximal tubule epithelial cells

    PubMed Central

    Song, Hana; Yoon, Sang Pil

    2016-01-01

    After renal injury, selective damage occurs in the proximal tubules as a result of inhibition of glycolysis. The molecular mechanism of damage is not known. Poly(ADP-ribose) polymerase (PARP) activation plays a critical role of proximal tubular cell death in several renal disorders. Here, we studied the role of PARP on glycolytic flux in pig kidney proximal tubule epithelial LLC-PK1 cells using XFp extracellular flux analysis. Poly(ADP-ribosyl)ation by PARP activation was increased approximately 2-fold by incubation of the cells in 10 mM glucose for 30 minutes, but treatment with the PARP inhibitor 3-aminobenzamide (3-AB) does-dependently prevented the glucose-induced PARP activation (approximately 14.4% decrease in 0.1 mM 3-AB–treated group and 36.7% decrease in 1 mM 3-AB–treated group). Treatment with 1 mM 3-AB significantly enhanced the glucose-mediated increase in the extracellular acidification rate (61.1±4.3 mpH/min vs. 126.8±6.2 mpH/min or approximately 2-fold) compared with treatment with vehicle, indicating that PARP inhibition increases only glycolytic activity during glycolytic flux including basal glycolysis, glycolytic activity, and glycolytic capacity in kidney proximal tubule epithelial cells. Glucose increased the activities of glycolytic enzymes including hexokinase, phosphoglucose isomerase, phosphofructokinase-1, glyceraldehyde-3-phosphate dehydrogenase, enolase, and pyruvate kinase in LLC-PK1 cells. Furthermore, PARP inhibition selectively augmented the activities of hexokinase (approximately 1.4-fold over vehicle group), phosphofructokinase-1 (approximately 1.6-fold over vehicle group), and glyceraldehyde-3-phosphate dehydrogenase (approximately 2.2-fold over vehicle group). In conclusion, these data suggest that PARP activation may regulate glycolytic activity via poly(ADP-ribosyl)ation of hexokinase, phosphofructokinase-1, and glyceraldehyde-3-phosphate dehydrogenase in kidney proximal tubule epithelial cells. PMID:27382509

  8. Control methods against invasive Aedes mosquitoes in Europe: a review.

    PubMed

    Baldacchino, Frédéric; Caputo, Beniamino; Chandre, Fabrice; Drago, Andrea; della Torre, Alessandra; Montarsi, Fabrizio; Rizzoli, Annapaola

    2015-11-01

    Five species of invasive Aedes mosquitoes have recently become established in Europe: Ae. albopictus, Ae. aegypti, Ae. japonicus japonicus, Ae. koreicus and Ae. atropalpus. These mosquitoes are a serious nuisance for people and are also competent vectors for several exotic pathogens such as dengue and chikungunya viruses. As they are a growing public health concern, methods to control these mosquitoes need to be implemented to reduce their biting and their potential for disease transmission. There is a crucial need to evaluate methods as part of an integrated invasive mosquito species control strategy in different European countries, taking into account local Aedes infestations and European regulations. This review presents the control methods available or in development against invasive Aedes mosquitoes, with a particular focus on those that can be implemented in Europe. These control methods are divided into five categories: environmental (source reduction), mechanical (trapping), biological (e.g. copepods, Bacillus thuringiensis var. israelensis, Wolbachia), chemical (insect growth regulators, pyrethroids) and genetic (sterile insect technique and genetically modified mosquitoes). We discuss the effectiveness, ecological impact, sustainability and stage of development of each control method. PMID:26037532

  9. Optical properties of human radicular dentin: ATR-FTIR characterization and dentine tubule direction influence on radicular post adhesion

    NASA Astrophysics Data System (ADS)

    Quinto, Jose; Zamataro, Claudia B.; Benetti, Carolina; Dias, Derly A.; Blay, Alberto; Zezell, Denise Maria

    2015-06-01

    Knowledge of dental structures is essential for understanding of laser interaction and its consequences during adhesion processes. Tubule density in dentin ranges from 4.900 to 90.000 per mm2, for diameters from 1 to 3 μm. Light propagation inside the tubules is associated with tubules orientation. To the best of our knowledge, there is no previous work in literature characterizing physical-chemical alterations in dentin. The dentin samples were irradiated with a Er,Cr:YSGG Laser at wavelength 2.78 μm, with an energy density of 9.46 J/cm2 , above the ablation threshold. ATRFTIR at wavenumbers 2000 to 700 cm-1 was used to evaluate the differences among third root region and tubules orientation.

  10. Progressive sheet-to-tubule transformation is a general mechanism for endoplasmic reticulum partitioning in dividing mammalian cells

    PubMed Central

    Puhka, Maija; Joensuu, Merja; Vihinen, Helena; Belevich, Ilya; Jokitalo, Eija

    2012-01-01

    The endoplasmic reticulum (ER) is both structurally and functionally complex, consisting of a dynamic network of interconnected sheets and tubules. To achieve a more comprehensive view of ER organization in interphase and mitotic cells and to address a discrepancy in the field (i.e., whether ER sheets persist, or are transformed to tubules, during mitosis), we analyzed the ER in four different mammalian cell lines using live-cell imaging, high-resolution electron microscopy, and three dimensional electron microscopy. In interphase cells, we found great variation in network organization and sheet structures among different cell lines. In mitotic cells, we show that the ER undergoes both spatial reorganization and structural transformation of sheets toward more fenestrated and tubular forms. However, the extent of spatial reorganization and sheet-to-tubule transformation varies among cell lines. Fenestration and tubulation of the ER correlates with a reduced number of membrane-bound ribosomes. PMID:22573885

  11. Effects of glucose on water and sodium reabsorption in the proximal convoluted tubule of rat kidney.

    PubMed Central

    Bishop, J H; Green, R; Thomas, S

    1978-01-01

    1. The effects of glucose on sodium and water reabsorption by rat renal proximal tubules was investigated by in situ microperfusion of segments of proximal tubules with solutions containing glucose or no glucose, with and without phlorizin. 2. Absence of glucose did not significantly alter net water flux. Sodium flux was reduced by about 10% but this was not statistically significant. 3. In the absence of glucose in the perfusion fluid net secretion of glucose occurred. 4. Phlorizin reduced either net reabsorption or net secretion of glucose; and net water flux. 5. The data suggest that in later parts of the proximal convoluted tubule some sodium may be co-transported with glucose, but that this represents only a small fraction of the total sodium reabsorption. 6. It is suggested that the glucose carrier is reversible and in appropriate circumstances could cause glucose secretion. 7. Although phlorizin alters net water flux the underlying mechanisms are not clear. 8. The calculated osmolality of the reabsorbate was significantly greater than the perfusate osmolality and greater than plasma osmolality although this was not quite significant statistically. PMID:633143

  12. Visualizing the origins of selfish de novo mutations in individual seminiferous tubules of human testes.

    PubMed

    Maher, Geoffrey J; McGowan, Simon J; Giannoulatou, Eleni; Verrill, Clare; Goriely, Anne; Wilkie, Andrew O M

    2016-03-01

    De novo point mutations arise predominantly in the male germline and increase in frequency with age, but it has not previously been possible to locate specific, identifiable mutations directly within the seminiferous tubules of human testes. Using microdissection of tubules exhibiting altered expression of the spermatogonial markers MAGEA4, FGFR3, and phospho-AKT, whole genome amplification, and DNA sequencing, we establish an in situ strategy for discovery and analysis of pathogenic de novo mutations. In 14 testes from men aged 39-90 y, we identified 11 distinct gain-of-function mutations in five genes (fibroblast growth factor receptors FGFR2 and FGFR3, tyrosine phosphatase PTPN11, and RAS oncogene homologs HRAS and KRAS) from 16 of 22 tubules analyzed; all mutations have known associations with severe diseases, ranging from congenital or perinatal lethal disorders to somatically acquired cancers. These results support proposed selfish selection of spermatogonial mutations affecting growth factor receptor-RAS signaling, highlight its prevalence in older men, and enable direct visualization of the microscopic anatomy of elongated mutant clones. PMID:26858415

  13. 50 Years of renal physiology from one man and the perfused tubule: Maurice B. Burg.

    PubMed

    Hamilton, Kirk L; Moore, Antoni B

    2016-08-01

    Technical advancements in research techniques in science are made in slow increments. Even so, large advances from insight and hard work of an individual with a single technique can have astonishing ramifications. Here, we examine the impact of Dr. Maurice B. Burg and the isolated perfused renal tubule technique and celebrate the 50th anniversary of the publication by Dr. Burg and his colleagues of their landmark paper in the American Journal of Physiology in 1966. In this study, we have taken a scientific visualization approach to study the scientific contributions of Dr. Burg and the isolated perfused tubule preparation as determining research impact by the number of research students, postdoctoral fellows, visiting scientists, and national and international collaborators. Additionally, we have examined the research collaborations (first and second generation scientists), established the migrational visualization of the first generation scientists who worked directly with Dr. Burg, quantified the metrics indices, identified and quantified the network of coauthorship of the first generation scientists with their second generation links, and determined the citations analyses of outputs of Dr. Burg and/or his first generation collaborators as coauthors. We also review the major advances in kidney physiology that have been made with the isolated perfused tubule technique. Finally, we are all waiting for the discoveries that the isolated perfused preparation technique will bring during the next 50 years. PMID:27122544

  14. Purinergic regulation of glucose and glutamine synthesis in isolated rabbit kidney-cortex tubules.

    PubMed

    Jagielski, Adam K; Wohner, Dagmara; Lietz, Tadeusz; Jarzyna, Robert; Derlacz, Rafał A; Winiarska, Katarzyna; Bryła, Jadwiga

    2002-08-15

    The effects of extracellular purinergic agonists and their breakdown products on glucose and glutamine synthesis in rabbit kidney-cortex tubules incubated with aspartate + glycerol or alanine + glycerol + octanoate were investigated. A rapid extracellular degradation of ATP was accompanied by an accumulation of AMP, inosine, and hypoxanthine. Extracellular ATP and its breakdown products accelerated glucose synthesis in renal tubules, while ammonium released from adenine-containing compounds enhanced glutamine synthesis and diminished the degree of gluconeogenesis stimulation. In contrast to AMP and inosine, ATP evoked calcium signals, while both ATP and inosine decreased intracellular cAMP content and accelerated the flux through fructose-1,6-bisphosphatase as concluded from changes in gluconeogenic intermediates. Since (i) the activity of partially purified renal fructose-1,6-bisphosphatase was increased upon protein phosphatase-1 treatment and decreased following treatment of previously dephosphorylated enzyme with protein kinase A catalytic subunit and (ii) both 8-bromoadenosine 3',5'-cyclic monophosphate and 8-(4-chlorophenyltio)-cAMP inhibited renal glucose synthesis, it seems likely that in rabbit renal tubules ATP and inosine stimulate gluconeogenesis via cAMP decrease, which favors the appearance of a more active, dephosphorylated form of fructose-1,6-bisphosphatase, a key gluconeogenic enzyme. PMID:12147256

  15. The Lowe Syndrome Protein OCRL1 Is Required for Endocytosis in the Zebrafish Pronephric Tubule

    PubMed Central

    Oltrabella, Francesca; Pietka, Grzegorz; Ramirez, Irene Barinaga-Rementeria; Mironov, Aleksandr; Starborg, Toby; Drummond, Iain A.; Hinchliffe, Katherine A.; Lowe, Martin

    2015-01-01

    Lowe syndrome and Dent-2 disease are caused by mutation of the inositol 5-phosphatase OCRL1. Despite our increased understanding of the cellular functions of OCRL1, the underlying basis for the renal tubulopathy seen in both human disorders, of which a hallmark is low molecular weight proteinuria, is currently unknown. Here, we show that deficiency in OCRL1 causes a defect in endocytosis in the zebrafish pronephric tubule, a model for the mammalian renal tubule. This coincides with a reduction in levels of the scavenger receptor megalin and its accumulation in endocytic compartments, consistent with reduced recycling within the endocytic pathway. We also observe reduced numbers of early endocytic compartments and enlarged vacuolar endosomes in the sub-apical region of pronephric cells. Cell polarity within the pronephric tubule is unaffected in mutant embryos. The OCRL1-deficient embryos exhibit a mild ciliogenesis defect, but this cannot account for the observed impairment of endocytosis. Catalytic activity of OCRL1 is required for renal tubular endocytosis and the endocytic defect can be rescued by suppression of PIP5K. These results indicate for the first time that OCRL1 is required for endocytic trafficking in vivo, and strongly support the hypothesis that endocytic defects are responsible for the renal tubulopathy in Lowe syndrome and Dent-2 disease. Moreover, our results reveal PIP5K as a potential therapeutic target for Lowe syndrome and Dent-2 disease. PMID:25838181

  16. Piecewise-Constant-Model-Based Interior Tomography Applied to Dentin Tubules

    PubMed Central

    Wei, Biao; Wang, Steve; Stock, Stuart R.; Yu, Hengyong

    2013-01-01

    Dentin is a hierarchically structured biomineralized composite material, and dentin's tubules are difficult to study in situ. Nano-CT provides the requisite resolution, but the field of view typically contains only a few tubules. Using a plate-like specimen allows reconstruction of a volume containing specific tubules from a number of truncated projections typically collected over an angular range of about 140°, which is practically accessible. Classical computed tomography (CT) theory cannot exactly reconstruct an object only from truncated projections, needless to say a limited angular range. Recently, interior tomography was developed to reconstruct a region-of-interest (ROI) from truncated data in a theoretically exact fashion via the total variation (TV) minimization under the condition that the ROI is piecewise constant. In this paper, we employ a TV minimization interior tomography algorithm to reconstruct interior microstructures in dentin from truncated projections over a limited angular range. Compared to the filtered backprojection (FBP) reconstruction, our reconstruction method reduces noise and suppresses artifacts. Volume rendering confirms the merits of our method in terms of preserving the interior microstructure of the dentin specimen. PMID:23509603

  17. Piecewise-constant-model-based interior tomography applied to dentin tubules.

    PubMed

    He, Peng; Wei, Biao; Wang, Steve; Stock, Stuart R; Yu, Hengyong; Wang, Ge

    2013-01-01

    Dentin is a hierarchically structured biomineralized composite material, and dentin's tubules are difficult to study in situ. Nano-CT provides the requisite resolution, but the field of view typically contains only a few tubules. Using a plate-like specimen allows reconstruction of a volume containing specific tubules from a number of truncated projections typically collected over an angular range of about 140°, which is practically accessible. Classical computed tomography (CT) theory cannot exactly reconstruct an object only from truncated projections, needless to say a limited angular range. Recently, interior tomography was developed to reconstruct a region-of-interest (ROI) from truncated data in a theoretically exact fashion via the total variation (TV) minimization under the condition that the ROI is piecewise constant. In this paper, we employ a TV minimization interior tomography algorithm to reconstruct interior microstructures in dentin from truncated projections over a limited angular range. Compared to the filtered backprojection (FBP) reconstruction, our reconstruction method reduces noise and suppresses artifacts. Volume rendering confirms the merits of our method in terms of preserving the interior microstructure of the dentin specimen. PMID:23509603

  18. Modeling oxygen consumption in the proximal tubule: effects of NHE and SGLT2 inhibition.

    PubMed

    Layton, Anita T; Vallon, Volker; Edwards, Aurélie

    2015-06-15

    The objective of this study was to investigate how physiological, pharmacological, and pathological conditions that alter sodium reabsorption (TNa) in the proximal tubule affect oxygen consumption (QO2 ) and Na(+) transport efficiency (TNa/QO2 ). To do so, we expanded a mathematical model of solute transport in the proximal tubule of the rat kidney. The model represents compliant S1, S2, and S3 segments and accounts for their specific apical and basolateral transporters. Sodium is reabsorbed transcellularly, via apical Na(+)/H(+) exchangers (NHE) and Na(+)-glucose (SGLT) cotransporters, and paracellularly. Our results suggest that TNa/QO2 is 80% higher in S3 than in S1-S2 segments, due to the greater contribution of the passive paracellular pathway to TNa in the former segment. Inhibition of NHE or Na-K-ATPase reduced TNa and QO2 , as well as Na(+) transport efficiency. SGLT2 inhibition also reduced proximal tubular TNa but increased QO2 ; these effects were relatively more pronounced in the S3 vs. the S1-S2 segments. Diabetes increased TNa and QO2 and reduced TNa/QO2 , owing mostly to hyperfiltration. Since SGLT2 inhibition lowers diabetic hyperfiltration, the net effect on TNa, QO2 , and Na(+) transport efficiency in the proximal tubule will largely depend on the individual extent to which glomerular filtration rate is lowered. PMID:25855513

  19. Effects of bioactive glass with and without mesoporous structures on desensitization in dentinal tubule occlusion

    NASA Astrophysics Data System (ADS)

    Chen, Wen-Cheng; Kung, Jung-Chang; Chen, Cheng-Hwei; Hsiao, Yu-Cheng; Shih, Chi-Jen; Chien, Chi-Sheng

    2013-10-01

    Bioactive glass (BG) is a potential material for treating dentin hypersensitivity due to its high ability of dissolution. In this study, conventional BG and BG with well-ordered mesopore structures (MBG) were applied for dentinal tubule occlusion. We used X-ray diffractometer (XRD), scanning electronic microscope (SEM), and Fourier transform infrared (FTIR) to investigate the physiochemical properties and the dentinal tubule occlusion ability of BG and MBG groups. The results showed that the major crystallite phase of MBG and BG agents was monocalcium phosphate monohydrate. MBG pastes, mixed with 30 and 40 wt% phosphoric acid hardening solutions, had the ability to create a penetration depth greater than 50 μm. These results showed that BG with mesoporous structures turned the pastes mixed with suitable phosphoric acid solution into a material with great ability for occluding dentinal tubules; it has a short reaction time and good operability, and these agents have better potential for the treatment of dentin hypersensitivity than BG without mesoporous structures.

  20. Piecewise-Constant-Model-Based Interior Tomography Applied to Dentin Tubules

    DOE PAGESBeta

    He, Peng; Wei, Biao; Wang, Steve; Stock, Stuart R.; Yu, Hengyong; Wang, Ge

    2013-01-01

    Dentin is a hierarchically structured biomineralized composite material, and dentin’s tubules are difficult to study in situ. Nano-CT provides the requisite resolution, but the field of view typically contains only a few tubules. Using a plate-like specimen allows reconstruction of a volume containing specific tubules from a number of truncated projections typically collected over an angular range of about 140°, which is practically accessible. Classical computed tomography (CT) theory cannot exactly reconstruct an object only from truncated projections, needless to say a limited angular range. Recently, interior tomography was developed to reconstruct a region-of-interest (ROI) from truncated data in amore » theoretically exact fashion via the total variation (TV) minimization under the condition that the ROI is piecewise constant. In this paper, we employ a TV minimization interior tomography algorithm to reconstruct interior microstructures in dentin from truncated projections over a limited angular range. Compared to the filtered backprojection (FBP) reconstruction, our reconstruction method reduces noise and suppresses artifacts. Volume rendering confirms the merits of our method in terms of preserving the interior microstructure of the dentin specimen.« less

  1. Regulation of seminiferous tubule-associated stem Leydig cells in adult rat testes.

    PubMed

    Li, Xiaoheng; Wang, Zhao; Jiang, Zhenming; Guo, Jingjing; Zhang, Yuxi; Li, Chenhao; Chung, Jinyong; Folmer, Janet; Liu, June; Lian, Qingquan; Ge, Renshan; Zirkin, Barry R; Chen, Haolin

    2016-03-01

    Testicular Leydig cells are the primary source of testosterone in males. Adult Leydig cells have been shown to arise from stem cells present in the neonatal testis. Once established, adult Leydig cells turn over only slowly during adult life, but when these cells are eliminated experimentally from the adult testis, new Leydig cells rapidly reappear. As in the neonatal testis, stem cells in the adult testis are presumed to be the source of the new Leydig cells. As yet, the mechanisms involved in regulating the proliferation and differentiation of these stem cells remain unknown. We developed a unique in vitro system of cultured seminiferous tubules to assess the ability of factors from the seminiferous tubules to regulate the proliferation of the tubule-associated stem cells, and their subsequent entry into the Leydig cell lineage. The proliferation of the stem Leydig cells was stimulated by paracrine factors including Desert hedgehog (DHH), basic fibroblast growth factor (FGF2), platelet-derived growth factor (PDGF), and activin. Suppression of proliferation occurred with transforming growth factor β (TGF-β). The differentiation of the stem cells was regulated positively by DHH, lithium- induced signaling, and activin, and negatively by TGF-β, PDGFBB, and FGF2. DHH functioned as a commitment factor, inducing the transition of stem cells to the progenitor stage and thus into the Leydig cell lineage. Additionally, CD90 (Thy1) was found to be a unique stem cell surface marker that was used to obtain purified stem cells by flow cytometry. PMID:26929346

  2. Experimental orchitis induced in rats by passive transfer of an antiserum to seminiferous tubule basement membrane.

    PubMed

    Lustig, L; Denduchis, B; González, N N; Puig, R P

    1978-09-01

    A multifocal damage of the testis was obtained when rats were injected intravenously or under the tunica albuginea of the testis with a rabbit antiseminiferous tubule basement membrane serum. The damage was characterized by foci of perivascular and peritubular infiltrates of mononuclear round cells, infolding, thickening, and rupture of the seminiferous tubular wall and different degrees of injury of the germinal epithelium such as, cell disorganization, cell sloughing, and atrophy. Delamination and thickening of seminiferous tubule basement membrane and vacuolization of the Sertoli cell cytoplasm was often observed by electron microscopy. A linear deposit of rabbit gamma-globulin was detected by immunohistochemical techniques along the basement membranes of the seminiferous tubules and vessels. Testicular damage was not detected in rats injected with normal rabbit serum, used as control. In the kidneys of rats injected intravenously with the immune serum, a deposit of rabbit gamma-globulin was detected along glomerular basement membrane. Focal areas of mononuclear cell infiltrates, hypercellularity of glomeruli and thickening of glomerular capillary walls and Bowman's capsule were also observed. PMID:367304

  3. Visualizing the origins of selfish de novo mutations in individual seminiferous tubules of human testes

    PubMed Central

    Maher, Geoffrey J.; McGowan, Simon J.; Giannoulatou, Eleni; Verrill, Clare; Goriely, Anne; Wilkie, Andrew O. M.

    2016-01-01

    De novo point mutations arise predominantly in the male germline and increase in frequency with age, but it has not previously been possible to locate specific, identifiable mutations directly within the seminiferous tubules of human testes. Using microdissection of tubules exhibiting altered expression of the spermatogonial markers MAGEA4, FGFR3, and phospho-AKT, whole genome amplification, and DNA sequencing, we establish an in situ strategy for discovery and analysis of pathogenic de novo mutations. In 14 testes from men aged 39–90 y, we identified 11 distinct gain-of-function mutations in five genes (fibroblast growth factor receptors FGFR2 and FGFR3, tyrosine phosphatase PTPN11, and RAS oncogene homologs HRAS and KRAS) from 16 of 22 tubules analyzed; all mutations have known associations with severe diseases, ranging from congenital or perinatal lethal disorders to somatically acquired cancers. These results support proposed selfish selection of spermatogonial mutations affecting growth factor receptor-RAS signaling, highlight its prevalence in older men, and enable direct visualization of the microscopic anatomy of elongated mutant clones. PMID:26858415

  4. Element composition of tubule cells in the inner stripe of the renal outer medulla.

    PubMed

    Beck, F X; Dörge, A; Ring, T; Sauer, M

    1989-01-01

    To obtain further insight into renal medullary function, element concentrations were determined in individual tubule cells of the outer medulla in the rat kidney using electron microprobe analysis on freeze-dried cryosections. In the cells of the thick ascending limb of Henle's loop the Na, P, Cl, and K concentrations (means +/- SEM) were: 9.5 +/- 0.6, 158.4 +/- 6.2, 25.6 +/- 1.2, and 135.3 +/- 4.8 mmol/kg wet weight, respectively. While similar Na, P, and K concentrations were observed in light and dark cells of the medullary collecting duct, Cl was markedly higher--55.0 +/- 2.8 mmol/kg wet weight--in the dark cells. The electrolyte concentrations of the thick ascending limb cells seen in the present study are in good agreement with ion activities reported for the isolated perfused thick ascending limb. The low cell Na and Cl concentrations provide a favorable driving force for passive cell entry of Na, Cl, and K across the apical membrane via the Na-2Cl-K cotransporter even at low tubule fluid NaCl concentrations. Although in hydropenic rats interstitial tonicity of the inner stripe is above isotonicity, electrolyte concentrations of inner stripe cells did not differ from those obtained in cortical tubule cells. This finding suggests that, similar to papillary cells, osmoadaptation of outer medullary cells is, at least partially, accomplished by organic osmolytes. PMID:2725433

  5. Functional integrity of proximal tubule cells: effects of temperature and preservation solutions.

    PubMed

    You, Y; Hirsch, D J; Morgunov, N S

    1993-06-01

    Electrophysiologic and morphologic changes during cooling and perfusion with preservation solutions in isolated perfused proximal straight tubules from Swiss white mice were investigated. In standard Ringer-substrate solution, cooling from 37 degrees C to 22 and 4 degrees C depolarized both transepithelial potential and basolateral cell membrane potential. Basolateral k+ transference number and cell membrane conductances were also significantly reduced. An increase in intracellular Na+ activity was observed only during cooling from 37 to 4 degrees C. No cell swelling was detected when tubules were perfused with Ringer-substrate solution at all three temperatures up to 1 h. Perfusion with Euro-Collins' (EC) solution at 37 degrees C resulted in rapid cell swelling, associated with rapid deterioration of transepithelial potential. Substitution of glucose with mannitol abolished the damaging effect of EC solution at 37 degrees C. EC perfusion at 22 degrees C also led to cell swelling and deterioration of transepithelial potential, but after a 10-min delay. In comparison, perfusion with University of Wisconsin (UW) solution at 22 or 37 degrees C had no effect on cell volume. Less damage to transepithelial potential was observed after the UW perfusion. It was concluded that EC solution is more damaging than UW solution to kidney tubules at 22 and 37 degrees C. The presence of EC solution in the renal interstitium during the rewarming phase may contribute significantly to reperfusion injuries in kidney transplantation. PMID:8338922

  6. Phospholipase Cβ1 induces membrane tubulation and is involved in caveolae formation.

    PubMed

    Inaba, Takehiko; Kishimoto, Takuma; Murate, Motohide; Tajima, Takuya; Sakai, Shota; Abe, Mitsuhiro; Makino, Asami; Tomishige, Nario; Ishitsuka, Reiko; Ikeda, Yasuo; Takeoka, Shinji; Kobayashi, Toshihide

    2016-07-12

    Lipid membrane curvature plays important roles in various physiological phenomena. Curvature-regulated dynamic membrane remodeling is achieved by the interaction between lipids and proteins. So far, several membrane sensing/sculpting proteins, such as Bin/amphiphysin/Rvs (BAR) proteins, are reported, but there remains the possibility of the existence of unidentified membrane-deforming proteins that have not been uncovered by sequence homology. To identify new lipid membrane deformation proteins, we applied liposome-based microscopic screening, using unbiased-darkfield microscopy. Using this method, we identified phospholipase Cβ1 (PLCβ1) as a new candidate. PLCβ1 is well characterized as an enzyme catalyzing the hydrolysis of phosphatidylinositol-4,5-bisphosphate (PIP2). In addition to lipase activity, our results indicate that PLCβ1 possessed the ability of membrane tubulation. Lipase domains and inositol phospholipids binding the pleckstrin homology (PH) domain of PLCβ1 were not involved, but the C-terminal sequence was responsible for this tubulation activity. Computational modeling revealed that the C terminus displays the structural homology to the BAR domains, which is well known as a membrane sensing/sculpting domain. Overexpression of PLCβ1 caused plasma membrane tubulation, whereas knockdown of the protein reduced the number of caveolae and induced the evagination of caveolin-rich membrane domains. Taken together, our results suggest a new function of PLCβ1: plasma membrane remodeling, and in particular, caveolae formation. PMID:27342861

  7. Interspecific Cross-Mating Between Aedes aegypti and Aedes albopictus Laboratory Strains: Implication of Population Density on Mating Behaviors.

    PubMed

    Marcela, P; Hassan, A Abu; Hamdan, A; Dieng, H; Kumara, T K

    2015-12-01

    Mating behavior between Aedes aegypti and Ae. albopictus, established colony strains were examined under laboratory conditions (30-cm(3) screened cages) for 5 consecutive days. The effect of selected male densities (30, 20, 10) and female density (20) on the number of swarming, mating pairs, eggs produced, and inseminated females were evaluated. Male densities significantly increased swarming behavior, mating pairs, and egg production of heterospecific females, but female insemination was reduced. Aedes aegypti males mate more readily with heterospecific females than do Ae. albopictus males. The current study suggests that Ae. aegypti males were not species-specific in mating, and if released into the field as practiced in genetically modified mosquito techniques, they may mate with both Ae. aegypti and Ae. albopictus females, hence reducing populations of both species by producing infertile eggs. PMID:26675452

  8. Modelling the ecology of the coastal mosquitoes Aedes vigilax and Aedes camptorhynchus at Port Pirie, South Australia.

    PubMed

    Kokkinn, M J; Duval, D J; Williams, C R

    2009-03-01

    Two mosquito species, Aedes camptorhynchus (Thomson) and Aedes vigilax (Skuse) (Diptera: Culicidae) are responsible for significant nuisance biting and disease transmission in southern coastal Australia. Mosquito abundance, tide height, temperature and rainfall data were collected over three summer seasons (2002, 2003, 2004) at Port Pirie, South Australia and subjected to statistical analysis to develop ecological models for predicting problem mosquito outbreaks. A logistic regression model for Ae. camptorhynchus gave a predictive R(2) of 0.30 using mean air temperature, whereas, for Ae. vigilax, tide height, mean air temperature and day length yielded a regression with an R(2) of 0.68. These models identify significant environmental drivers for both species and may be useful in the prediction of future outbreaks, particularly of Ae. vigilax. PMID:19239618

  9. T-tubule disorganization and reduced synchrony of Ca2+ release in murine cardiomyocytes following myocardial infarction.

    PubMed

    Louch, William E; Mørk, Halvor K; Sexton, Joseph; Strømme, Taevje A; Laake, Petter; Sjaastad, Ivar; Sejersted, Ole M

    2006-07-15

    In cardiac myocytes, initiation of excitation-contraction coupling is highly localized near the T-tubule network. Myocytes with a dense T-tubule network exhibit rapid and homogeneous sarcoplasmic reticulum (SR) Ca(2+) release throughout the cell. We examined whether progressive changes in T-tubule organization and Ca(2+) release synchrony occur in a murine model of congestive heart failure (CHF). Myocardial infarction (MI) was induced by ligation of the left coronary artery, and CHF was diagnosed by echocardiography (left atrial diameter >2.0 mm). CHF mice were killed at 1 or 3 weeks following MI (1-week CHF, 3-week CHF) and cardiomyocytes were isolated from viable regions of the septum, excluding the MI border zone. Septal myocytes from SHAM-operated mice served as controls. T-tubules were visualized by confocal microscopy in cells stained with di-8-ANEPPS. SHAM cells exhibited a regular striated T-tubule pattern. However, 1-week CHF cells showed slightly disorganized T-tubule structure, and more profound disorganization occurred in 3-week CHF with irregular gaps between adjacent T-tubules. Line-scan images of Ca(2+) transients (fluo-4 AM, 1 Hz) showed that regions of delayed Ca(2+) release occurred at these gaps. Three-week CHF cells exhibited an increased number of delayed release regions, and increased overall dyssynchrony of Ca(2+) release. A common pattern of Ca(2+) release in 3-week CHF was maintained between consecutive transients, and was not altered by forskolin application. Thus, progressive T-tubule disorganization during CHF promotes dyssynchrony of SR Ca(2+) release which may contribute to the slowing of SR Ca(2+) release in this condition. PMID:16709642

  10. Oviposition Behavior in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in Response to the Presence of Heterospecific and Conspecific Larvae.

    PubMed

    Gonzalez, Paula V; González Audino, Paola A; Masuh, Héctor M

    2016-03-01

    In mosquitoes, location of suitable sites for oviposition requires a set of visual, tactile, and olfactory cues that influences females before laying their eggs. The ability of gravid females to distinguish among potential oviposition sites that will or will not support the growth, development, and survival of their progeny is critical. Aedes aegypti (L.) and Aedes albopictus (Skuse) share ecological niches, being highly competitive in larval stage. We studied the oviposition behavior of both species in the presence of larvae of one or the other species (heterospecific or conspecific larvae). The number of eggs laid by gravid females on oviposition sites (water with different or the same species of Aedes larvae) were compared. The presence and density of heterospecific or conspecific larvae had a positive or negative effect on the ovipositional responses, measured as an oviposition activity index. For both species, the oviposition was not affected by heterospecific larvae with densities between 10 and 100 larvae in water, but a strong attractant behavior was observed for a density of 500 larvae in water. For Ae. albopictus in the presence of larvae of the same species (conspecific oviposition), we observed an attractant effect for larvae density of 10 but not for 100 or 500 larvae in water. Instead, for Ae. aegypti, we observed attraction only for 100 larvae, not for 10 or 500 larvae. Results presented here provide an additional insight about oviposition behavior responses of gravid females in the presence of conspecific and heterospecific larvae in breeding sites. PMID:26634825

  11. Long-term surveillance data and patterns of invasion by Aedes albopictus in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used GIS and long-term mosquito surveillance data from Lake County, Pasco County, Manatee County, and Sarasota County, Florida to look at patterns of invasion by Aedes albopictus with respect to changes in populations of resident Aedes aegypti. We investigated associations of rainfall with chang...

  12. Mitochondrial markers to distinguish two species of Aedes Neomelaniconion (Diptera: Culicidae) from Kenya

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aedes mcintoshi and Ae circumluteolus are two common flood water mosquito species collected in Kenya. Both belong to the Aedes subgenus Neomelaniconion, a relatively large subgenus with representative species in the Ethiopian, Oriental, Australian and Palearctic regions. In Kenya, both have been imp...

  13. Incorporating domain knowledge for tubule detection in breast histopathology using O'Callaghan neighborhoods

    NASA Astrophysics Data System (ADS)

    Basavanhally, Ajay; Yu, Elaine; Xu, Jun; Ganesan, Shridar; Feldman, Michael; Tomaszewski, John; Madabhushi, Anant

    2011-03-01

    An important criterion for identifying complicated objects with multiple attributes is the use of domain knowledge which reflects the precise spatial linking of the constituent attributes. Hence, simply detecting the presence of the low-level attributes that constitute the object, even in cases where these attributes might be detected in spatial proximity to each other is usually not a robust strategy. The O'Callaghan neighborhood is an ideal vehicle for characterizing objects comprised of multiple attributes spatially connected to each other in a precise fashion because it allows for modeling and imposing spatial distance and directional constraints on the object attributes. In this work we apply the O'Callaghan neighborhood to the problem of tubule identification on hematoxylin and eosin (H & E) stained breast cancer (BCa) histopathology, where a tubule is characterized by a central lumen surrounded by cytoplasm and a ring of nuclei around the cytoplasm. The detection of tubules is important because tubular density is an important predictor in cancer grade determination. In the context of ER+ BCa, grade has been shown to be strongly linked to disease aggressiveness and patient outcome. The more standard pattern recognition approaches to detection of complex objects typically involve training classifiers for low-level attributes individually. For tubule detection, the spatial proximity of lumen, cytoplasm, and nuclei might suggest the presence of a tubule. However such an approach could also suffer from false positive errors due to the presence of fat, stroma, and other lumen-like areas that could be mistaken for tubules. In this work, tubules are identified by imposing spatial and distance constraints using O'Callaghan neighborhoods between the ring of nuclei around each lumen. In this work, cancer nuclei in each image are found via a color deconvolution scheme, which isolates the hematoxylin stain, thereby enabling automated detection of individual cell nuclei

  14. Specific detection of the floodwater mosquitoes Aedes sticticus and Aedes vexans DNA in predatory diving beetles.

    PubMed

    Vinnersten, Thomas Z Persson; Halvarsson, Peter; Lundström, Jan O

    2015-08-01

    Floodwater mosquitoes (Diptera: Culicidae) are associated with periodically flooded wet meadows, marshes, and swamps in floodplains of major rivers worldwide, and their larvae are abundant in the shallow parts of flooded areas. The nuisance caused by the blood-seeking adult female mosquitoes motivates mosquito control. Larviciding with Bacillus thuringiensis israelensis is considered the most environmentally safe method. However, some concern has been raised whether aquatic predatory insects could be indirectly affected by this reduction in a potential vital prey. Top predators in the temporary wetlands in the River Dalälven floodplains are diving beetles (Coleoptera: Dytiscidae), and Aedes sticticus and Ae. vexans are the target species for mosquito control. For detailed studies on this aquatic predator-prey system, we developed a polymerase chain reaction (PCR) assay for detection of mosquito DNA in the guts of medium-sized diving beetles. Primers were designed for amplifying short mitochondrial DNA fragments of the cytochrome C oxidase subunit I (COI) gene in Ae. sticticus and Ae. vexans, respectively. Primer specificity was confirmed and half-life detectability of Ae. sticticus DNA in diving beetle guts was derived from a feeding and digestion experiment. The Ae. sticticus DNA within diving beetle guts was detected up to 12 h postfeeding, and half-life detectability was estimated to 5.6 h. In addition, field caught diving beetles were screened for Ae. sticticus and Ae. vexans DNA and in 14% of the diving beetles one or both mosquito species were detected, showing that these mosquito species are utilized as food by the diving beetles. PMID:24895318

  15. Vector Competence of Aedes aegypti and Aedes polynesiensis Populations from French Polynesia for Chikungunya Virus

    PubMed Central

    Richard, Vaea; Paoaafaite, Tuterarii; Cao-Lormeau, Van-Mai

    2016-01-01

    Background From October 2014 to March 2015, French Polynesia experienced for the first time a chikungunya outbreak. Two Aedes mosquitoes may have contributed to chikungunya virus (CHIKV) transmission in French Polynesia: the worldwide distributed Ae. aegypti and the Polynesian islands-endemic Ae. polynesiensis mosquito. Methods To investigate the vector competence of French Polynesian populations of Ae. aegypti and Ae. polynesiensis for CHIKV, mosquitoes were exposed per os at viral titers of 7 logs tissue culture infectious dose 50%. At 2, 6, 9, 14 and 21 days post-infection (dpi), saliva was collected from each mosquito and inoculated onto C6/36 mosquito cells to check for the presence of CHIKV infectious particles. Legs and body (thorax and abdomen) of each mosquito were also collected at the different dpi and submitted separately to viral RNA extraction and CHIKV real-time RT-PCR. Results CHIKV infection rate, dissemination and transmission efficiencies ranged from 7–90%, 18–78% and 5–53% respectively for Ae. aegypti and from 39–41%, 3–17% and 0–14% respectively for Ae. polynesiensis, depending on the dpi. Infectious saliva was found as early as 2 dpi for Ae. aegypti and from 6 dpi for Ae. polynesiensis. Our laboratory results confirm that the French Polynesian population of Ae. aegypti is highly competent for CHIKV and they provide clear evidence for Ae. polynesiensis to act as an efficient CHIKV vector. Conclusion As supported by our findings, the presence of two CHIKV competent vectors in French Polynesia certainly contributed to enabling this virus to quickly disseminate from the urban/peri-urban areas colonized by Ae. aegypti to the most remote atolls where Ae. polynesiensis is predominating. Ae. polynesiensis was probably involved in the recent chikungunya outbreaks in Samoa and the Cook Islands. Moreover, this vector may contribute to the risk for CHIKV to emerge in other Polynesian islands like Fiji, and more particularly Wallis where there

  16. Larval mosquito habitat utilization and community dynamics of Aedes albopictus and Aedes japonicus (Diptera: Culicidae).

    PubMed

    Bartlett-Healy, Kristen; Unlu, Isik; Obenauer, Peter; Hughes, Tony; Healy, Sean; Crepeau, Taryn; Farajollahi, Ary; Kesavaraju, Banu; Fonseca, Dina; Schoeler, George; Gaugler, Randy; Strickman, Daniel

    2012-07-01

    Aedes albopictus (Skuse) and Ae. japonicus (Theobald) are important container-inhabiting mosquitoes that transmit disease agents, outcompete native species, and continue to expand their range in the United States. Both species deposit eggs in natural and artificial containers and thrive in peridomestic environments. The goal of our study was to examine the types and characteristics of containers that are most productive for these species in the northeastern United States. In total, 306 containers were sampled in urban, suburban, and rural areas of New Jersey. Multiple biotic and abiotic factors were recorded in an attempt to identify variables associated with the productivity of each species. Based on pupal abundance and density of container types, results showed that tires, trash cans, and planter dishes were the most important containers for Ae. albopictus, while planter dishes were the most important containers for Ae. japonicus. Container color (black and gray), material (rubber), and type (tires) were correlated with species presence for Ae. albopictus and Ae. japonicus. These factors may play a role in the selection of oviposition sites by female mosquitoes or in the survival of their progeny. Differences in species composition and abundance were detected between areas classified as urban, suburban, and rural. In urban and suburban areas, Ae. albopictus was more abundant in container habitats than Ae. japonicus; however, Ae. japonicus was more abundant in rural areas, and when water temperatures were below 14 degrees C. Our results suggest many variables can influence the presence of Ae. albopictus and Ae. japonicus in container habitats in northeastern United States. PMID:22897041

  17. Rapid development of vasopressin-induced hydroosmosis in kidney collecting tubules measured by a new fluorescence technique.

    PubMed Central

    Kuwahara, M.; Berry, C. A.; Verkman, A. S.

    1988-01-01

    The pre-steady-state kinetics of the vasopressin-induced increase in collecting tubule osmotic water permeability (Pf) has been measured by a new fluorescence technique. Isolated cortical collecting tubules (CCT) from rabbit kidney were perfused with physiological buffers containing the impermeant fluorophores fluorescein sulfonate (FS) and pyrenetetrasulfonic acid (PTSA). Tubules were subject to a 120 mOsm bath-to-lumen osmotic gradient in the presence and absence of 250 microU/ml vasopressin. The magnitude of transepithelial volume flow was determined from the self-quenching of FS, or from the ratio of PTSA/FS fluorescence, measured at 380 nm excitation and 420 +/- 10 nm (PTSA) and greater than 530 nm (FS) emission wavelengths. Pf was calculated from the magnitude of transepithelial volume flow, lumen and bath osmolarities, lumen perfusion rate, and tubule geometry. The instrument response time for a change in bath osmolality was less than 3 s. At 37 degrees C, CCT Pf was (in units of cm/s x 10(4] 13 +/- 2 (mean +/- SE, 16 tubules) before, and 227 +/- 10 after addition of vasopressin to the bath. CCT Pf began to increase in 23 +/- 3 s after vasopressin addition and was half-maximal after 186 +/- 20 s. At 23 degrees C, Pf was 9 +/- 1 (seven tubules) before, and 189 +/- 12 after vasopressin addition. Pf began to increase in 40 +/- 4 s and was half-maximal after 195 +/- 35 s. After vasopressin removal from the bath, Pf decreased to its baseline value with a half-time of 14 min. These results establish a direct fluorescence method to monitor instantaneous transepithelial Pf in perfused tubules and show a very fast stimulation of CCT Pf in response to vasopressin. Images FIGURE 2 PMID:3224145

  18. Proximal tubule NHE3 activity is inhibited by beta-arrestin-biased angiotensin II type 1 receptor signaling.

    PubMed

    Carneiro de Morais, Carla P; Polidoro, Juliano Z; Ralph, Donna L; Pessoa, Thaissa D; Oliveira-Souza, Maria; Barauna, Valério G; Rebouças, Nancy A; Malnic, Gerhard; McDonough, Alicia A; Girardi, Adriana C C

    2015-10-15

    Physiological concentrations of angiotensin II (ANG II) upregulate the activity of Na(+)/H(+) exchanger isoform 3 (NHE3) in the renal proximal tubule through activation of the ANG II type I (AT1) receptor/G protein-coupled signaling. This effect is key for maintenance of extracellular fluid volume homeostasis and blood pressure. Recent findings have shown that selective activation of the beta-arrestin-biased AT1 receptor signaling pathway induces diuresis and natriuresis independent of G protein-mediated signaling. This study tested the hypothesis that activation of this AT1 receptor/beta-arrestin signaling inhibits NHE3 activity in proximal tubule. To this end, we determined the effects of the compound TRV120023, which binds to the AT1R, blocks G-protein coupling, and stimulates beta-arrestin signaling on NHE3 function in vivo and in vitro. NHE3 activity was measured in both native proximal tubules, by stationary microperfusion, and in opossum proximal tubule (OKP) cells, by Na(+)-dependent intracellular pH recovery. We found that 10(-7) M TRV120023 remarkably inhibited proximal tubule NHE3 activity both in vivo and in vitro. Additionally, stimulation of NHE3 by ANG II was completely suppressed by TRV120023 both in vivo as well as in vitro. Inhibition of NHE3 activity by TRV120023 was associated with a decrease in NHE3 surface expression in OKP cells and with a redistribution from the body to the base of the microvilli in the rat proximal tubule. These findings indicate that biased signaling of the beta-arrestin pathway through the AT1 receptor inhibits NHE3 activity in the proximal tubule at least in part due to changes in NHE3 subcellular localization. PMID:26246427

  19. Osmotic diuresis in a mathematical model of the rat proximal tubule.

    PubMed

    Weinstein, A M

    1986-05-01

    Solute reabsorption in the presence of an osmotic load has been examined in a model of the rat proximal convoluted tubule. The model is a computer simulation of a 0.5-cm segment of tubule comprised of compliant cellular and paracellular compartments, which tracks the luminal profiles of Na, K, Cl, HCO3, phosphate, glucose, and urea. In one series of calculations, the peritubular and initial luminal glucose concentrations are varied from 1.0 to 50 mmol/liter. The resulting proximal reabsorption of glucose increases monotonically to 1.5 nmol X s-1 X cm-2. Sodium reabsorption increases with glucose perfusion concentrations between 1.0 and 10 mmol/liter and then declines with greater glucose loads. Above 10 mmol/liter glucose, there is progressive decline in mean luminal Na concentration so that diffusive paracellular backflux, as well as decreased convective reabsorption, are responsible for the natriuresis. Diuresis per se blunts reabsorption of species requiring the development of lumen-to-bath concentration gradients (i.e., K, Cl, and urea). Diminished bicarbonate reabsorption is also predicted with large glucose loads due to intraepithelial alkalinization. This derives both from cellular depolarization and bicarbonate trapping (interspace closure). It is also observed that when interspace closure occurs, a region of intraepithelial K depletion may be formed, promoting diffusive reabsorption of potassium across the tight junction. Thus a 'middle compartment model' for potassium may provide a means of achieving tubule fluid-to-plasma K ratios less than 1.0, in the absence of specific cellular uptake mechanisms. PMID:3706538

  20. Regulation of glomerulotubular balance. III. Implication of cytosolic calcium in flow-dependent proximal tubule transport.

    PubMed

    Du, Zhaopeng; Weinbaum, Sheldon; Weinstein, Alan M; Wang, Tong

    2015-04-15

    In the proximal tubule, axial flow (drag on brush-border microvilli) stimulates Na(+) and HCO3 (-) reabsorption by modulating both Na/H exchanger 3 (NHE3) and H-ATPase activity, a process critical to glomerulotubular balance. We have also demonstrated that blocking the angiotensin II receptor decreases baseline transport, but preserves the flow effect; dopamine leaves baseline fluxes intact, but abrogates the flow effect. In the current work, we provide evidence implicating cytosolic calcium in flow-dependent transport. Mouse proximal tubules were microperfused in vitro at perfusion rates of 5 and 20 nl/min, and reabsorption of fluid (Jv) and HCO3 (-) (JHCO3) were measured. We examined the effect of high luminal Ca(2+) (5 mM), 0 mM Ca(2+), the Ca(2+) chelator BAPTA-AM, the inositol 1,4,5-trisphosphate (IP3) receptor antagonist 2-aminoethoxydiphenyl borate (2-APB), and the Ca-ATPase inhibitor thapsigargin. In control tubules, increasing perfusion rate from 5 to 20 nl/min increased Jv by 62% and JHCO3 by 104%. With respect to Na(+) reabsorption, high luminal Ca(2+) decreased transport at low flow, but preserved the flow-induced increase; low luminal Ca(2+) had little impact; both BAPTA and 2-APB had no effect on baseline flux, but abrogated the flow effect; thapsigargin decreased baseline flow, leaving the flow effect intact. With respect to HCO3 (-) reabsorption, high luminal Ca(2+) decreased transport at low flow and mildly diminished the flow-induced increase; low luminal Ca(2+) had little impact; both BAPTA and 2-APB had no effect on baseline flux, but abrogated the flow effect. These data implicate IP3 receptor-mediated intracellular Ca(2+) signaling as a critical step in transduction of microvillous drag to modulate Na(+) and HCO3 (-) transport. PMID:25651568

  1. Bicarbonate absorption stimulates active calcium absorption in the rat proximal tubule.

    PubMed Central

    Bomsztyk, K; Calalb, M B

    1988-01-01

    To evaluate the effect of luminal bicarbonate on calcium reabsorption, rat proximal tubules were perfused in vivo. Perfusion solution contained mannitol to reduce water flux to zero. Total Ca concentration was measured by atomic absorption spectrometry, Ca ion concentration in the tubule lumen (CaL2+) and the peritubular capillary (CaP2+), and luminal pH (pHL) with ion-selective microelectrodes and transepithelial voltage (VTE) with conventional microelectrodes. When tubules were perfused with buffer-free Cl-containing solution, net Ca absorption (JCa) averaged 3.33 pmol/min. Even though VTE was 1.64 mV lumen-positive, CaL2+, 1.05 mM, did not fall below the concentration in the capillary blood, 1.07 mM. When 27 mM of Cl was replaced with HCO3, there was luminal fluid acidification. Despite a decrease in VTE and CaL2+, JCa increased to 7.13 pmol/min, indicating that the enhanced JCa could not be accounted for by the reduced electrochemical gradient, delta CCa. When acetazolamide or an analogue of amiloride was added to the HCO3 solution, JCa was not different from the buffer-free solution, suggesting that HCO3-stimulated JCa may be linked to acidification. To further test this hypothesis, we used 27 mM Hepes as the luminal buffer. With Hepes there was luminal fluid acidification and JCa was not different from the buffer-free solution but delta CCa was significantly reduced, indicating enhanced active calcium transport. We conclude from the results of the present study that HCO3 stimulates active Ca absorption, a process that may be linked to acidification-mediated HCO3 absorption. PMID:3366902

  2. Mercury induces the externalization of phosphatidyl-serine in human renal proximal tubule (HK-2) cells.

    PubMed

    Sutton, Dwayne J; Tchounwou, Paul B

    2007-06-01

    The underlying mechanism for the biological activity of inorganic mercury is believed to be the high affinity binding of divalent mercuric cations to thiols of sulfhydryl groups of proteins. A comprehensive analysis of published data indicates that inorganic mercury is one of the most environmentally abundant toxic metals, is a potent and selective nephrotoxicant that preferentially accumulates in the kidneys, and is known to produce cellular injury in the kidneys. Binding sites are present in the proximal tubules, and it is in the epithelial cells of these tubules that toxicants such as inorganic mercury are reabsorbed. This can affect the enzymatic activity and the structure of various proteins. Mercury may alter protein and membrane structure and function in the epithelial cells and this alteration may result in long term residual effects. This research was therefore designed to evaluate the dose-response relationship in human renal proximal tubule (HK-2) cells following exposure to inorganic mercury. Cytotoxicity was evaluated using the MTT assay for cell viability. The Annexin-V assay was performed by flow cytometry to determine the extent of phosphatidylserine externalization. Cells were exposed to mercury for 24 hours at doses of 0, 1, 2, 3, 4, 5, and 6 microg/mL. Cytotoxicity experiments yielded a LD50 value of 4.65 +/- 0.6 microg/mL indicating that mercury is highly toxic. The percentages of cells undergoing early apoptosis were 0.70 +/- 0.03%, 10.0 +/- 0.02%, 11.70 +/- 0.03%, 15.20 +/- 0.02%, 16.70 +/- 0.03%, 24.20 +/-0.02%, and 25.60 +/- 0.04% at treatments of 0, 1, 2, 3, 4, 5, and 6 microg/mL of mercury respectively. This indicates a dose-response relationship with regard to mercury-induced cytotoxicity and the externalization of phosphatidylserine in HK-2 cells. PMID:17617677

  3. Correlated behavior implicates stromules in increasing the interactive surface between plastids and ER tubules

    PubMed Central

    Schattat, Martin; Barton, Kiah

    2011-01-01

    Stromules are extended by plastids but the underlying basis for their extension and retraction had not been understood until recently. Our live-imaging aided observations on coincident plastid stromule branching and ER tubule dynamics open out new areas of investigation relating to these rapid subcellular interactions. This addendum provides a testable hypothesis on the formation of stromules, which argues against the need for new membrane incorporation and suggests that stromal extensions might result from a remodeling of the plastid envelope membrane in an ER aided manner. PMID:21448009

  4. Repellent effect of plant essential oils against Aedes albopictus.

    PubMed

    Yang, Pin; Ma, Yajun

    2005-12-01

    Six essential oils: asteraceae oil, rutaceae oil, mentha piperta oil, carvacryl oil, citronella oil, and eucalyptus oil were tested for evaluation of their repellent effects against Aedes albopictus mosquitoes under laboratory conditions. Only citronella oil and eucalyptus oil were tested with human beings. There was considerable protection for mice. Carvacryl oil (7%) provided 100% protection for mice after 7 h. Eucalyptus oil (15%) gave protection to humans for least 3 h; the protection time was prolonged to 5 h after adding 5% vanillin. The mixture could be developed into a practical product after the field evaluation. PMID:16599157

  5. History of domestication and spread of Aedes aegypti - A Review

    PubMed Central

    Powell, Jeffrey R; Tabachnick, Walter J

    2013-01-01

    The adaptation of insect vectors of human diseases to breed in human habitats (domestication) is one of the most important phenomena in medical entomology. Considerable data are available on the vector mosquito Aedes aegypti in this regard and here we integrate the available information including genetics, behaviour, morphology, ecology and biogeography of the mosquito, with human history. We emphasise the tremendous amount of variation possessed by Ae. aegypti for virtually all traits considered. Typological thinking needs to be abandoned to reach a realistic and comprehensive understanding of this important vector of yellow fever, dengue and Chikungunya. PMID:24473798

  6. Identification of Essential Containers for Aedes Larval Breeding to Control Dengue in Dhaka, Bangladesh

    PubMed Central

    Ferdousi, Farhana; Yoshimatsu, Shoji; Ma, Enbo; Sohel, Nazmul; Wagatsuma, Yukiko

    2015-01-01

    Dengue fever (DF), one of the most important emerging arboviral diseases, is transmitted through the bite of container breeding mosquitoes Aedes aegypti and Aedes albopictus. A household entomological survey was conducted in Dhaka from August through October 2000 to inspect water-holding containers in indoor, outdoor, and rooftop locations for Aedes larvae. The objective of this study was to determine mosquito productivity of each container type and to identify some risk factors of households infested with Aedes larvae. Of 9,222 households inspected, 1,306 (14.2%) were positive for Aedes larvae. Of 38,777 wet containers examined, 2,272 (5.8%) were infested with Aedes larvae. Containers used to hold water, such as earthen jars, tanks, and drums were the most common containers for larval breeding. Tires in outdoor and rooftop locations of the households were also important for larval breeding. Although present in abundance, buckets were of less importance. Factors such as independent household, presence of a water storage system in the house, and fully/partly shaded outdoors were found to be significantly associated with household infestation of Aedes larvae. Identification and subsequent elimination of the most productive containers in a given area may potentially reduce mosquito density to below a level at which dengue transmission may be halted. PMID:26865829

  7. Identification of Essential Containers for Aedes Larval Breeding to Control Dengue in Dhaka, Bangladesh.

    PubMed

    Ferdousi, Farhana; Yoshimatsu, Shoji; Ma, Enbo; Sohel, Nazmul; Wagatsuma, Yukiko

    2015-12-01

    Dengue fever (DF), one of the most important emerging arboviral diseases, is transmitted through the bite of container breeding mosquitoes Aedes aegypti and Aedes albopictus. A household entomological survey was conducted in Dhaka from August through October 2000 to inspect water-holding containers in indoor, outdoor, and rooftop locations for Aedes larvae. The objective of this study was to determine mosquito productivity of each container type and to identify some risk factors of households infested with Aedes larvae. Of 9,222 households inspected, 1,306 (14.2%) were positive for Aedes larvae. Of 38,777 wet containers examined, 2,272 (5.8%) were infested with Aedes larvae. Containers used to hold water, such as earthen jars, tanks, and drums were the most common containers for larval breeding. Tires in outdoor and rooftop locations of the households were also important for larval breeding. Although present in abundance, buckets were of less importance. Factors such as independent household, presence of a water storage system in the house, and fully/partly shaded outdoors were found to be significantly associated with household infestation of Aedes larvae. Identification and subsequent elimination of the most productive containers in a given area may potentially reduce mosquito density to below a level at which dengue transmission may be halted. PMID:26865829

  8. Short-term functional adaptation of aquaporin-1 surface expression in the proximal tubule, a component of glomerulotubular balance.

    PubMed

    Pohl, Marcus; Shan, Qixian; Petsch, Thomas; Styp-Rekowska, Beata; Matthey, Patricia; Bleich, Markus; Bachmann, Sebastian; Theilig, Franziska

    2015-06-01

    Transepithelial water flow across the renal proximal tubule is mediated predominantly by aquaporin-1 (AQP1). Along this nephron segment, luminal delivery and transepithelial reabsorption are directly coupled, a phenomenon called glomerulotubular balance. We hypothesized that the surface expression of AQP1 is regulated by fluid shear stress, contributing to this effect. Consistent with this finding, we found that the abundance of AQP1 in brush border apical and basolateral membranes was augmented >2-fold by increasing luminal perfusion rates in isolated, microperfused proximal tubules for 15 minutes. Mouse kidneys with diminished endocytosis caused by a conditional deletion of megalin or the chloride channel ClC-5 had constitutively enhanced AQP1 abundance in the proximal tubule brush border membrane. In AQP1-transfected, cultured proximal tubule cells, fluid shear stress or the addition of cyclic nucleotides enhanced AQP1 surface expression and concomitantly diminished its ubiquitination. These effects were also associated with an elevated osmotic water permeability. In sum, we have shown that luminal surface expression of AQP1 in the proximal tubule brush border membrane is regulated in response to flow. Cellular trafficking, endocytosis, an intact endosomal compartment, and controlled protein stability are the likely prerequisites for AQP1 activation by enhanced tubular fluid shear stress, serving to maintain glomerulotubular balance. PMID:25270072

  9. Excretion of NaCl and KCl loads in mosquitoes. 2. Effects of the small molecule Kir channel modulator VU573 and its inactive analog VU342

    PubMed Central

    Rouhier, Matthew F.; Hine, Rebecca M.; Park, Seokhwan Terry; Raphemot, Rene; Denton, Jerod; Piermarini, Peter M.

    2014-01-01

    The effect of two small molecules VU342 and VU573 on renal functions in the yellow fever mosquito Aedes aegypti was investigated in vitro and in vivo. In isolated Malpighian tubules, VU342 (10 μM) had no effect on the transepithelial secretion of Na+, K+, Cl−, and water. In contrast, 10 μM VU573 first stimulated and then inhibited the transepithelial secretion of fluid when the tubules were bathed in Na+-rich or K+-rich Ringer solution. The early stimulation was blocked by bumetanide, suggesting the transient stimulation of Na-K-2Cl cotransport, and the late inhibition of fluid secretion was consistent with the known block of AeKir1, an Aedes inward rectifier K+ channel, by VU573. VU342 and VU573 at a hemolymph concentration of about 11 μM had no effect on the diuresis triggered by hemolymph Na+ or K+ loads. VU342 at a hemolymph concentration of 420 μM had no effect on the diuresis elicited by hemolymph Na+ or K+ loads. In contrast, the same concentration of VU573 significantly diminished the Na+ diuresis by inhibiting the urinary excretion of Na+, Cl−, and water. In K+-loaded mosquitoes, 420 μM VU573 significantly diminished the K+ diuresis by inhibiting the urinary excretion of K+, Na+, Cl−, and water. We conclude that 1) the effects of VU573 observed in isolated Malpighian tubules are overwhelmed in vivo by the diuresis triggered with the coinjection of Na+ and K+ loads, and 2) at a hemolymph concentration of 420 μM VU573 affects Kir channels systemically, including those that might be involved in the release of diuretic hormones. PMID:25056106

  10. Excretion of NaCl and KCl loads in mosquitoes. 2. Effects of the small molecule Kir channel modulator VU573 and its inactive analog VU342.

    PubMed

    Rouhier, Matthew F; Hine, Rebecca M; Park, Seokhwan Terry; Raphemot, Rene; Denton, Jerod; Piermarini, Peter M; Beyenbach, Klaus W

    2014-10-01

    The effect of two small molecules VU342 and VU573 on renal functions in the yellow fever mosquito Aedes aegypti was investigated in vitro and in vivo. In isolated Malpighian tubules, VU342 (10 μM) had no effect on the transepithelial secretion of Na(+), K(+), Cl(-), and water. In contrast, 10 μM VU573 first stimulated and then inhibited the transepithelial secretion of fluid when the tubules were bathed in Na(+)-rich or K(+)-rich Ringer solution. The early stimulation was blocked by bumetanide, suggesting the transient stimulation of Na-K-2Cl cotransport, and the late inhibition of fluid secretion was consistent with the known block of AeKir1, an Aedes inward rectifier K(+) channel, by VU573. VU342 and VU573 at a hemolymph concentration of about 11 μM had no effect on the diuresis triggered by hemolymph Na(+) or K(+) loads. VU342 at a hemolymph concentration of 420 μM had no effect on the diuresis elicited by hemolymph Na(+) or K(+) loads. In contrast, the same concentration of VU573 significantly diminished the Na(+) diuresis by inhibiting the urinary excretion of Na(+), Cl(-), and water. In K(+)-loaded mosquitoes, 420 μM VU573 significantly diminished the K(+) diuresis by inhibiting the urinary excretion of K(+), Na(+), Cl(-), and water. We conclude that 1) the effects of VU573 observed in isolated Malpighian tubules are overwhelmed in vivo by the diuresis triggered with the coinjection of Na(+) and K(+) loads, and 2) at a hemolymph concentration of 420 μM VU573 affects Kir channels systemically, including those that might be involved in the release of diuretic hormones. PMID:25056106

  11. Seasonal abundance of Aedes albopictus in selected urban and suburban areas in Penang, Malaysia.

    PubMed

    Rozilawati, H; Zairi, J; Adanan, C R

    2007-06-01

    Ovitrap surveillance was conducted in a selected urban area and suburban area, ie. Taman Permai Indah(TPI) and Kampung Pasir Gebu (KPG) in Penang for 14 months. It was found that Aedes albopictus was the most abundant Aedes species in both study areas, even though a small percentage of Aedes aegypti and Culex quinquefasciatus were found to breed simultaneously in the same ovitrap. This study indicated that the main dengue vector was Ae. albopictus. A strong correlation was found between rainfall and egg population in both of the study sites (r = 0.982 and r = 0.918). PMID:17568381

  12. Primary cultures of rabbit renal proximal tubule cells: I. Growth and biochemical characteristics.

    PubMed

    Aleo, M D; Taub, M L; Nickerson, P A; Kostyniak, P J

    1989-09-01

    Before the usefulness of a new in vitro model can be ascertained, the model must be properly defined and characterized. This study presents the growth rate and biochemical characteristics of rabbit renal proximal tubule cells in primary culture over a 2-wk culture period. When grown in a hormonally defined, antibiotic-free medium these cells form confluent monolayer cultures within 7 d after plating. Multicellular dome formation, an indicator of transepithelial solute transport, was expressed after confluent cultures were formed. The activity of the cytosolic enzyme, lactate dehydrogenase, and the lysosomal enzyme, N-acetyl-glucosaminidase, increased 14- and 2-fold during the first 8 d of culture, respectively. In contrast, the activity of a brush border enzyme, alkaline phosphatase, decreased 85% within the first 8 d of culture. Release of these enzyme markers into the culture medium, which are routinely used to measure cytotoxicity, stabilized after 8 d in culture. The ratio of cellular protein to DNA changed according to the state of cellular growth. Values rose from 0.035 mg protein/micrograms DNA in preconfluent cultures to 0.059 mg protein/micrograms DNA in confluent cultures. These results document the characteristics of a primary proximal tubule cell culture system for future studies in in vitro toxicology. PMID:2793776

  13. Megalin and cubilin in proximal tubule protein reabsorption: from experimental models to human disease.

    PubMed

    Nielsen, Rikke; Christensen, Erik Ilsø; Birn, Henrik

    2016-01-01

    Proximal tubule protein uptake is mediated by 2 receptors, megalin and cubilin. These receptors rescue a variety of filtered ligands, including biomarkers, essential vitamins, and hormones. Receptor gene knockout animal models have identified important functions of the receptors and have established their essential role in modulating urinary protein excretion. Rare genetic syndromes associated with dysfunction of these receptors have been identified and characterized, providing additional information on the importance of these receptors in humans. Using various disease models in combination with receptor gene knockout, the implications of receptor dysfunction in acute and chronic kidney injury have been explored and have pointed to potential new roles of these receptors. Based on data from animal models, this paper will review current knowledge on proximal tubule endocytic receptor function and regulation, and their role in renal development, protein reabsorption, albumin uptake, and normal renal physiology. These findings have implications for the pathophysiology and diagnosis of proteinuric renal diseases. We will examine the limitations of the different models and compare the findings to phenotypic observations in inherited human disorders associated with receptor dysfunction. Furthermore, evidence from receptor knockout mouse models as well as human observations suggesting a role of protein receptors for renal disease will be discussed in light of conditions such as chronic kidney disease, diabetes, and hypertension. PMID:26759048

  14. Receptor-mediated endocytosis of lysozyme in renal proximal tubules of the frog Rana temporaria.

    PubMed

    Seliverstova, E V; Prutskova, N P

    2015-01-01

    The mechanism of protein reabsorption in the kidney of lower vertebrates remains insufficiently investigated in spite of raising interest to the amphibian and fish kidneys as a useful model for physiological and pathophysiological examinations. In the present study, we examined the renal tubular uptake and the internalization rote of lysozyme after its intravenous injection in the wintering frog Rana temporaria using immunohisto- and immunocytochemistry and specific markers for some endocytic compartments. The distinct expression of megalin and cubilin in the proximal tubule cells of lysozyme-injected frogs was revealed whereas kidney tissue of control animals showed no positive immunoreactivity. Lysozyme was detected in the apical endocytic compartment of the tubular cells and colocalized with clathrin 10 min after injection. After 20 min, lysozyme was located in the subapical compartment negative to clathrin (endosomes), and intracellular trafficking of lysozyme was coincided with the distribution of megalin and cubilin. However, internalized protein was retained in the endosomes and did not reach lysosomes within 30 min after treatment that may indicate the inhibition of intracellular trafficking in hibernating frogs. For the first time, we provided the evidence that lysozyme is filtered through the glomeruli and absorbed by receptor-mediated clathrin-dependent endocytosis in the frog proximal tubule cells. Thus, the protein uptake in the amphibian mesonephros is mediated by megalin and cubilin that confirms a critical role of endocytic receptors in the renal reabsorption of proteins in amphibians as in mammals. PMID:26150156

  15. Ability of three desensitizing agents in dentinal tubule obliteration and durability: An in vitro study

    PubMed Central

    Pathan, Azher Banu; Bolla, Nagesh; Kavuri, Sarath Raj; Sunil, Chukka Ram; Damaraju, Bhargavi; Pattan, Sadhiq Khan

    2016-01-01

    Aim: The purpose of this study was to evaluate the effectiveness of three desensitizing agents on dentinal tubule obliteration and their durability in use on the dentinal tubules. Materials and Methods: Sixty specimens were obtained from 30 extracted sound human maxillary first premolars. Each tooth was mesiodistally sectioned to obtain 30 buccal and 30 lingual surfaces, and enamel was removed in order to simulate hypersensitive dentin. Specimens were divided into four groups with 15 specimens each. Group 1 samples were immersed in artificial saliva, Group 2 samples were coated with Vivasens, Group 3 samples were coated with VOCO Admira Protect, and Group 4 samples were coated with Neo Active Apatite suspension. These specimens were examined under scanning electron microscope (SEM) to find out the occluding ability of the respective products. The specimens were brushed to find out their durability for 1 week and 1 month and were examined under SEM. Statistical Analysis: The results were statistically analyzed by analysis of variance (ANOVA) and Tukey's test. Results: Group 1 differed significantly from the Vivasens, Admira, and Neo Active Apatite groups at 5% level of significance (P < 0.05). The Vivasens group differed significantly from the Admira and Neo Active Apatite groups at 5% level of significance (P < 0.05). Conclusion: The Ormocer-based Admira Protect showed the best results. PMID:26957790

  16. Chloride secretagogues stimulate inositol phosphate formation in shark rectal gland tubules cultured in suspension

    SciTech Connect

    Ecay, T.W.; Valentich, J.D. )

    1991-03-01

    Neuroendocrine activation of transepithelial chloride secretion by shark rectal gland cells is associated with increases in cellular cAMP, cGMP, and free calcium concentrations. We report here on the effects of several chloride secretagogues on inositol phosphate formation in cultured rectal gland tubules. Vasoactive intestinal peptide (VIP), atriopeptin (AP), and ionomycin increase the total inositol phosphate levels of cultured tubules, as measured by ion exchange chromatography. Forskolin, a potent chloride secretagogue, has no effect on inositol phosphate formation. The uptake of {sup 3}H-myo-inositol into phospholipids is very slow, preventing the detection of increased levels of inositol trisphosphate. However, significant increases in inositol monophosphate (IP1) and inositol biphosphate (IP2) were measured. The time course of VIP- and AP-stimulated IP1 and IP2 formation is similar to the effects of these agents on the short-circuit current responses of rectal gland monolayer cultures. In addition, aluminum fluoride, an artificial activator of guanine nucleotide-binding proteins, stimulates IP1 and IP2 formation. We conclude that rectal gland cells contain VIP and AP receptors coupled to the activation of phospholipase C. Coupling may be mediated by G-proteins. Receptor-stimulated increases in inositol phospholipid metabolism is one mechanism leading to increased intracellular free calcium concentrations, an important regulatory event in the activation of transepithelial chloride secretion by shark rectal gland epithelial cells.

  17. Calcium-activated chloride currents in primary cultures of rabbit distal convoluted tubule.

    PubMed

    Bidet, M; Tauc, M; Rubera, I; de Renzis, G; Poujeol, C; Bohn, M T; Poujeol, P

    1996-10-01

    Chloride (Cl-) conductances were studied in primary cultures of rabbit distal convoluted tubule (very early distal "bright" convoluted tubule, DCTb) by the whole cell patch-clamp technique. We identified a Cl- current activated by 2 microM extracellular ionomycin. The kinetics of the macroscopic current were time dependent for depolarizing potentials with a slow developing component. The steady state current presented outward rectification, and the ion selectivity sequence was I- > Br- > > Cl > glutamate. The current was inhibited by 0.1 mM 5-nitro-2-(3-phenylpropyl-amino)benzoic acid, 1 mM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, and 1 mM diphenylamine-2-carboxylate. To identify the location of the Cl- conductance, 6-methoxy-N-(3-sulfopropyl)quinolinium fluorescence experiments were carried out in confluent cultures developed on collagen-coated permeable filters. Cl- removal from the apical solution induced a Cl- efflux that was stimulated by 10 microM forskolin. Forskolin had no effect on the basolateral Cl- permeability Cl- substitution in the basolateral solution induced an efflux stimulated by 2 microM ionomycin or 50 microM extracellular ATP Ionomycin had no effect on the apical Cl- fluxes. Thus cultured DCTb cells exhibit Ca(2+)-activated Cl- channels located in the basolateral membrane. This Cl- permeability was active at a resting membrane potential and could participate in the Cl- reabsorption across the DCTb in control conditions. PMID:8898026

  18. Potential role of cytoplasmic calcium ions in the regulation of sodium transport in renal tubules.

    PubMed

    Frindt, G; Lee, C O; Yang, J M; Windhager, E E

    1988-01-01

    Experimental maneuvers that increase intracellular calcium ion levels inhibit sodium transport by renal tubules. In the isolated perfused renal tubule, intracellular calcium ion activity (aiCa) changes in response to alterations in the magnitude of the electrochemical potential gradient for sodium ions across the basolateral cell membrane. However, a potassium-induced depolarization of this cell boundary does not cause a rise but rather a fall in intracellular calcium ion levels. Ionomycin raises aiCa without causing intracellular acidification. This observation does not support the view that high cytosolic calcium produces intracellular acidification. At least in the case of ionomycin, the inhibition of sodium transport appears to be due to ionophore-induced increases in aiCa. The changes in intracellular calcium ion concentration found in the different experimental conditions studied were consistent with the notion that cytosolic calcium ions may mediate a feedback mechanism that links the luminal entry to the peritubular extrusion of sodium ions. The mechanisms by which cytosolic calcium alters entry is not yet clear but recent experiments suggest an indirect effect on sodium channel activity. PMID:3279295

  19. A molecular mechanism to regulate lysosome motility for lysosome positioning and tubulation.

    PubMed

    Li, Xinran; Rydzewski, Nicholas; Hider, Ahmad; Zhang, Xiaoli; Yang, Junsheng; Wang, Wuyang; Gao, Qiong; Cheng, Xiping; Xu, Haoxing

    2016-04-01

    To mediate the degradation of biomacromolecules, lysosomes must traffic towards cargo-carrying vesicles for subsequent membrane fusion or fission. Mutations of the lysosomal Ca(2+) channel TRPML1 cause lysosomal storage disease (LSD) characterized by disordered lysosomal membrane trafficking in cells. Here we show that TRPML1 activity is required to promote Ca(2+)-dependent centripetal movement of lysosomes towards the perinuclear region (where autophagosomes accumulate) following autophagy induction. ALG-2, an EF-hand-containing protein, serves as a lysosomal Ca(2+) sensor that associates physically with the minus-end-directed dynactin-dynein motor, while PtdIns(3,5)P(2), a lysosome-localized phosphoinositide, acts upstream of TRPML1. Furthermore, the PtdIns(3,5)P(2)-TRPML1-ALG-2-dynein signalling is necessary for lysosome tubulation and reformation. In contrast, the TRPML1 pathway is not required for the perinuclear accumulation of lysosomes observed in many LSDs, which is instead likely to be caused by secondary cholesterol accumulation that constitutively activates Rab7-RILP-dependent retrograde transport. Ca(2+) release from lysosomes thus provides an on-demand mechanism regulating lysosome motility, positioning and tubulation. PMID:26950892

  20. Flagellar cells and ciliary cells in the renal tubule of elasmobranchs.

    PubMed

    Lacy, E R; Luciano, L; Reale, E

    1989-01-01

    Flagella or cilia are present on most epithelial cells in the renal tubule of elasmobranch fishes (little skate, spiny dogfish, smooth dogfish, Atlantic sharpnose, scalloped hammerhead, cow-nosed ray). Flagellar cells, those with numerous flagella ordered in one, two, or more rows on the luminal surface, are shown here for the first time in a vertebrate. The flagellar cells are intercalated among other epithelial cells, each bearing a single cilium, from Bowman's capsule to the third subdivision of the intermediate segment of the nephron. The flagella form undulated ribbons up to 55 microns long. In every ribbon the axis of the central pair of microtubules in the axoneme is oriented parallel to the long axis of the flagellar row. This suggests a beat perpendicular to these two axes. The arrangement of the flagella in ribbons most likely promotes movement of glomerular filtrate down the renal tubule. Cells bearing numerous cilia occur in the large collecting ducts of spiny dogfish but without apparent preferential orientation of the cilia. PMID:2575649

  1. A Bioartificial Renal Tubule Device Embedding Human Renal Stem/Progenitor Cells

    PubMed Central

    Sciancalepore, Anna Giovanna; Sallustio, Fabio; Girardo, Salvatore; Gioia Passione, Laura; Camposeo, Andrea; Mele, Elisa; Di Lorenzo, Mirella; Costantino, Vincenzo; Schena, Francesco Paolo; Pisignano, Dario

    2014-01-01

    We present a bio-inspired renal microdevice that resembles the in vivo structure of a kidney proximal tubule. For the first time, a population of tubular adult renal stem/progenitor cells (ARPCs) was embedded into a microsystem to create a bioengineered renal tubule. These cells have both multipotent differentiation abilities and an extraordinary capacity for injured renal cell regeneration. Therefore, ARPCs may be considered a promising tool for promoting regenerative processes in the kidney to treat acute and chronic renal injury. Here ARPCs were grown to confluence and exposed to a laminar fluid shear stress into the chip, in order to induce a functional cell polarization. Exposing ARPCs to fluid shear stress in the chip led the aquaporin-2 transporter to localize at their apical region and the Na+K+ATPase pump at their basolateral portion, in contrast to statically cultured ARPCs. A recovery of urea and creatinine of (20±5)% and (13±5)%, respectively, was obtained by the device. The microengineered biochip here-proposed might be an innovative “lab-on-a-chip” platform to investigate in vitro ARPCs behaviour or to test drugs for therapeutic and toxicological responses. PMID:24498117

  2. alpha. - and. beta. -adrenergic receptors in proximal tubules of rat kidney

    SciTech Connect

    Sundaresan, P.R.; Fortin, T.L.; Kelvie, S.L. )

    1987-11-01

    Proximal tubules were isolated from the rat kidney by collagenase digestion of the cortical tissue followed by Percoll gradient centrifugation. Microscopic and hormone-stimulated adenylate cyclase activity studies proved the purity of the preparation. ({sup 3}H)Prazosin, ({sup 3}H)rauwolscine, and ({sup 125}I)iodocyanopindolol were used to identify and quantitate respectively the {alpha}{sub 1}-, {alpha}{sub 2}- and {beta}-adrenergic receptors. Proximal tubular (F{sub 4}) particulate fraction was compared against other cortical nephron segment (F{sub 1},F{sub 2}) fractions and the total collagenase-digested cortex particulate suspension (F{sub t}). Proximal tubules were enriched in {alpha}{sub 1}- and {alpha}{sub 2}-adrenergic receptors compared with. The fractions enriched in glomeruli and distal tubular segments had relatively low concentrations of {alpha}{sub 1}- and {alpha}{sub 2}-adrenergic receptors. Isoproterenol-stimulated adenylate cyclase activities in the different fractions corroborated well with the pattern suggested by the ({sup 125}I)iodocyanopindolol binding studies. The results suggest that whole-cortex preparation radioligand binding studies may reflect proximal tubular {alpha}{sub 1}- and {alpha}{sub 2}-adrenergic receptor changes quite well. They may, however, miss or give erroneous impressions about {beta}-adrenergic receptor changes occurring in different cortical nephron segments.

  3. Receptor-Mediated Endocytosis of Lysozyme in Renal Proximal Tubules of the Frog Rana Temporaria

    PubMed Central

    Seliverstova, E.V.

    2015-01-01

    The mechanism of protein reabsorption in the kidney of lower vertebrates remains insufficiently investigated in spite of raising interest to the amphibian and fish kidneys as a useful model for physiological and pathophysiological examinations. In the present study, we examined the renal tubular uptake and the internalization rote of lysozyme after its intravenous injection in the wintering frog Rana temporaria using immunohisto- and immunocytochemistry and specific markers for some endocytic compartments. The distinct expression of megalin and cubilin in the proximal tubule cells of lysozyme-injected frogs was revealed whereas kidney tissue of control animals showed no positive immunoreactivity. Lysozyme was detected in the apical endocytic compartment of the tubular cells and colocalized with clathrin 10 min after injection. After 20 min, lysozyme was located in the subapical compartment negative to clathrin (endo-somes), and intracellular trafficking of lysozyme was coincided with the distribution of megalin and cubilin. However, internalized protein was retained in the endosomes and did not reach lysosomes within 30 min after treatment that may indicate the inhibition of intra-cellular trafficking in hibernating frogs. For the first time, we provided the evidence that lysozyme is filtered through the glomeruli and absorbed by receptor-mediated clathrin-dependent endocytosis in the frog proximal tubule cells. Thus, the protein uptake in the amphibian mesonephros is mediated by megalin and cubilin that confirms a critical role of endocytic receptors in the renal reabsorption of proteins in amphibians as in mammals. PMID:26150156

  4. Role of the paracellular pathway in isotonic fluid movement across the renal tubule.

    PubMed

    Boulpaep, E L; Sackin, H

    1977-01-01

    Evidence for a highly permeable paracellular shunt in the proximal tubule is reviewed. The paracellular pathway is described as a crucial site for the regulation of net absorption and for solute-solvent interaction. Available models for the coupling of salt and water transport are assessed with respect to the problem of isotonic water movement. Two new models are proposed taking into account that the tight junctions are permeable to salt and water and that active transport sites for sodium are distributed uniformly along the lateral cell membrane. The first model (continuous model) is a modification of Diamond and Bossert's proposal using different assumptions and boundary conditions. No appreciable standing gradients are predicted by this model. The second model (compartmental model) is an expansion of Curran's double membrane model by including additional compartments and driving forces. Both models predict a reabsorbate which is not isosmotic. For the particular case of the proximal tubule it is shown that in the presence of a leaky epithelium these deviations from isotonicity might have escaped experimental observation. PMID:331692

  5. In Vitro Ability of a Novel Nanohydroxyapatite Oral Rinse to Occlude Dentine Tubules

    PubMed Central

    Hill, Robert G.; Chen, Xiaohui; Gillam, David G.

    2015-01-01

    Objectives. The aim of the study was to investigate the ability of a novel nanohydroxyapatite (nHA) desensitizing oral rinse to occlude dentine tubules compared to selected commercially available desensitizing oral rinses. Methods. 25 caries-free extracted molars were sectioned into 1 mm thick dentine discs. The dentine discs (n = 25) were etched with 6% citric acid for 2 minutes and rinsed with distilled water, prior to a 30-second application of test and control oral rinses. Evaluation was by (1) Scanning Electron Microscopy (SEM) of the dentine surface and (2) fluid flow measurements through a dentine disc. Results. Most of the oral rinses failed to adequately cover the dentine surface apart from the nHa oral rinse. However the hydroxyapatite, 1.4% potassium oxalate, and arginine/PVM/MA copolymer oral rinses, appeared to be relatively more effective than the nHA test and negative control rinses (potassium nitrate) in relation to a reduction in fluid flow measurements. Conclusions. Although the novel nHA oral rinse demonstrated the ability to occlude the dentine tubules and reduce the fluid flow measurements, some of the other oral rinses appeared to demonstrate a statistically significant reduction in fluid flow through the dentine disc, in particular the arginine/PVM/MA copolymer oral rinse. PMID:26161093

  6. BLOC-2 targets recycling endosomal tubules to melanosomes for cargo delivery

    PubMed Central

    Dennis, Megan K.; Mantegazza, Adriana R.; Snir, Olivia L.; Tenza, Danièle; Acosta-Ruiz, Amanda; Delevoye, Cédric; Zorger, Richard; Sitaram, Anand; de Jesus-Rojas, Wilfredo; Ravichandran, Keerthana; Rux, John; Sviderskaya, Elena V.; Bennett, Dorothy C.; Raposo, Graça; Setty, Subba Rao Gangi

    2015-01-01

    Hermansky–Pudlak syndrome (HPS) is a group of disorders characterized by the malformation of lysosome-related organelles, such as pigment cell melanosomes. Three of nine characterized HPS subtypes result from mutations in subunits of BLOC-2, a protein complex with no known molecular function. In this paper, we exploit melanocytes from mouse HPS models to place BLOC-2 within a cargo transport pathway from recycling endosomal domains to maturing melanosomes. In BLOC-2–deficient melanocytes, the melanosomal protein TYRP1 was largely depleted from pigment granules and underwent accelerated recycling from endosomes to the plasma membrane and to the Golgi. By live-cell imaging, recycling endosomal tubules of wild-type melanocytes made frequent and prolonged contacts with maturing melanosomes; in contrast, tubules from BLOC-2–deficient cells were shorter in length and made fewer, more transient contacts with melanosomes. These results support a model in which BLOC-2 functions to direct recycling endosomal tubular transport intermediates to maturing melanosomes and thereby promote cargo delivery and optimal pigmentation. PMID:26008744

  7. A conserved amphipathic helix is required for membrane tubule formation by Yop1p

    PubMed Central

    Brady, Jacob P.; Claridge, Jolyon K.; Smith, Peter G.; Schnell, Jason R.

    2015-01-01

    The integral membrane proteins of the DP1 (deleted in polyposis) and reticulon families are responsible for maintaining the high membrane curvature required for both smooth endoplasmic reticulum (ER) tubules and the edges of ER sheets, and mutations in these proteins lead to motor neuron diseases, such as hereditary spastic paraplegia. Reticulon/DP1 proteins contain reticulon homology domains (RHDs) that have unusually long hydrophobic segments and are proposed to adopt intramembrane helical hairpins that stabilize membrane curvature. We have characterized the secondary structure and dynamics of the DP1 family protein produced from the YOP1 gene (Yop1p) and identified a C-terminal conserved amphipathic helix (APH) that, on its own, interacts strongly with negatively charged membranes and is necessary for membrane tubule formation. Analyses of DP1 and reticulon family members indicate that most, if not all, contain C-terminal sequences capable of forming APHs. Together, these results indicate that APHs play a previously unrecognized role in RHD membrane curvature stabilization. PMID:25646439

  8. Transport of Streptococcus pneumoniae Capsular Polysaccharide in MHC Class II Tubules

    PubMed Central

    Stephen, Tom Li; Fabri, Mario; Groneck, Laura; Röhn, Till A; Hafke, Helena; Robinson, Nirmal; Rietdorf, Jens; Schrama, David; Becker, Jürgen C; Plum, Georg; Krönke, Martin; Kropshofer, Harald; Kalka-Moll, Wiltrud M

    2007-01-01

    Bacterial capsular polysaccharides are virulence factors and are considered T cell–independent antigens. However, the capsular polysaccharide Sp1 from Streptococcus pneumoniae serotype 1 has been shown to activate CD4+ T cells in a major histocompatibility complex (MHC) class II–dependent manner. The mechanism of carbohydrate presentation to CD4+ T cells is unknown. We show in live murine dendritic cells (DCs) that Sp1 translocates from lysosomal compartments to the plasma membrane in MHCII-positive tubules. Sp1 cell surface presentation results in reduction of self-peptide presentation without alteration of the MHCII self peptide repertoire. In DM-deficient mice, retrograde transport of Sp1/MHCII complexes resulting in T cell–dependent immune responses to the polysaccharide in vitro and in vivo is significantly reduced. The results demonstrate the capacity of a bacterial capsular polysaccharide antigen to use DC tubules as a vehicle for its transport as an MHCII/saccharide complex to the cell surface for the induction of T cell activation. Furthermore, retrograde transport requires the functional role of DM in self peptide–carbohydrate exchange. These observations open new opportunities for the design of vaccines against microbial encapsulated pathogens. PMID:17367207

  9. Mechanism of increased clearance of glycated albumin by proximal tubule cells.

    PubMed

    Wagner, Mark C; Myslinski, Jered; Pratap, Shiv; Flores, Brittany; Rhodes, George; Campos-Bilderback, Silvia B; Sandoval, Ruben M; Kumar, Sudhanshu; Patel, Monika; Ashish; Molitoris, Bruce A

    2016-05-01

    Serum albumin is the most abundant plasma protein and has a long half-life due to neonatal Fc receptor (FcRn)-mediated transcytosis by many cell types, including proximal tubule cells of the kidney. Albumin also interacts with, and is modified by, many small and large molecules. Therefore, the focus of the present study was to address the impact of specific known biological albumin modifications on albumin-FcRn binding and cellular handling. Binding at pH 6.0 and 7.4 was performed since FcRn binds albumin strongly at acidic pH and releases it after transcytosis at physiological pH. Equilibrium dissociation constants were measured using microscale thermophoresis. Since studies have shown that glycated albumin is excreted in the urine at a higher rate than unmodified albumin, we studied glucose and methylgloxal modified albumins (21 days). All had reduced affinity to FcRn at pH 6.0, suggesting these albumins would not be returned to the circulation via the transcytotic pathway. To address why modified albumin has reduced affinity, we analyzed the structure of the modified albumins using small-angle X-ray scattering. This analysis showed significant structural changes occurring to albumin with glycation, particularly in the FcRn-binding region, which could explain the reduced affinity to FcRn. These results offer an explanation for enhanced proximal tubule-mediated sorting and clearance of abnormal albumins. PMID:26887834

  10. Larvicidal Activity of Citrus Limonoids against Aedes albopictus Larvae

    PubMed Central

    Bilal, Hazrat; Akram, Waseem; Ali-Hassan, Soaib

    2012-01-01

    Background: Development of insecticide resistance occurred due to the continuous and misuse of synthetic insecticides therefore, the recent study was conducted to explore eco-friendly plant extracts that have some potential to suppress mosquito larval population. Methods: WHO recommended mosquito larval bioassay method for insecticide was used while for the analysis of citrus oils for limonin and nomilin content HPLC was used. Results: Among the two citrus cultivars tested as larvicide against Aedes albopictus, valencia late (Citrus sinensis) was the best in terms of LC50 (297 ppm), % mortality (97%) and LT50 (18.49 hours) then freutrall early (Citrus reticulate) with LC50 (377.4 ppm), % mortality (88%) and LT50 (31 hours), While nomilin gave lowest LC50 (121.04 ppm) than limonin (382.22 ppm) after 72 hours of exposure. Valencia late also had more limonin and nomilin (377 μg/ml and 21.19 μg/ml) than freutrall early (5.29 μg/ml and 3.89 μg/ml) respectively. Conclusion: Valencia late showed best results in term of LC50, LT50 and percentage mortality against Aedes albopictus as it has more amount of nomilin then freutrall early, however further evaluation in the field conditions is required. PMID:23378967

  11. Molecular Analysis of the Aedes aegypti Carboxypeptidase Gene Family

    PubMed Central

    Isoe, Jun; Zamora, Jorge; Miesfeld, Roger L.

    2009-01-01

    To gain a better understanding of coordinate regulation of protease gene expression in the mosquito midgut, we undertook a comprehensive molecular study of digestive carboxypeptidases in Aedes aegypti. Through a combination of cDNA cloning using degenerate PCR primers, and database mining of the recently completed Ae. aegypti genome, we cloned and characterized 18 Ae. aegypti carboxypeptidase genes. Bioinformatic analysis revealed that 11 of these genes belong to the carboxypeptidase A family (AaCPA-I through AaCPA-XI), and seven to the carboxypeptidase B gene family (AaCPB-I through AaCPB-VII). Phylogenetic analysis of 32 mosquito carboxypeptidases from five different species indicated that most of the sequence divergence in the carboxypeptidase gene family occurred prior to the separation of Aedes and Anopheles mosquito lineages. Unlike the CPA genes that are scattered throughout the Ae. aegypti genome, six of seven CPB genes were found to be located within a single 120 kb genome contig, suggesting that they most likely arose from multiple gene duplication events. Quantitative expression analysis revealed that 11 of the Ae. aegypti carboxypeptidase genes were induced up to 40-fold in the midgut in response to blood meal feeding, with peak expression times ranging from 3-36 hours post-feeding depending on the gene. PMID:18977440

  12. Regulatory Forum Opinion Piece*: Dispelling Confusing Pathology Terminology: Recognition and Interpretation of Selected Rodent Renal Tubule Lesions.

    PubMed

    Seely, John Curtis; Frazier, Kendall S

    2015-06-01

    Renal tubule lesions often prove troublesome for toxicologic pathologists because of the diverse nature and interrelated cell types within the kidney and the presence of spontaneous lesions with overlapping morphologies similar to those induced by renal toxicants. Although there are a number of guidance documents available citing straightforward diagnostic criteria of tubule lesions for the pathologist to refer to, most are presented without further advice on the when to or to the why and the why not of diagnosing one lesion over another. Documents presenting diagnostic perspectives and recommendations derived from an author's experience are limited since guidance documents are generally based on descriptive observations. In this Regulatory Forum opinion piece, the authors attempt to dispel confusing renal tubule lesion terminology in laboratory animal species by suggesting histological advice on the recognition and interpretation of these complex entities. PMID:25869578

  13. Binding and degradation of /sup 125/I-insulin by renal glomeruli and tubules isolated from rats

    SciTech Connect

    Meezan, E.; Freychet, P.

    1982-04-01

    Isolated rat renal glomeruli and tubules were shown to exhibit specific binding of /sup 125/I-insulin and enzymatic degradation of the hormone. Binding to both renal fractions reached a plateau by 1 h at 22/sup 0/C and increased linearly with increasing protein concentrations. Binding was inhibited in both preparations by insulin and its analogues in the order of relative potency: insulin > despentapeptide insulin > proinsulin, but insulin was ten times more potent in inhibiting /sup 125/I-insulin binding to glomeruli than that to tubules, indicating a different affinity of receptors for the hormone in the two renal fractions (about 17 versus 210 ..mu..g unlabelled insulin/1 inhibiting 50% of the /sup 125/I-insulin binding to glomeruli and tubules, respectively). Bound /sup 125/I-insulin dissociated at a faster rate from tubules than from glomeruli; this release was accelerated by unlabelled insulin in both renal fractions, but to a greater extent in glomeruli than in tubules. Two-thirds of the total bound material released from glomeruli was found to be intact insulin as measured by trichloroacetic acid precipitation, whereas only one-third of the material released from tubules was intact. No direct relationship between binding and degradation of /sup 125/I-insulin in these renal fractions could be demonstrated, however, because of the release of proteolytic enzymes into the incubation medium resulting in almost all degradation being extracellular. Although differing in their affinity for /sup 125/I-insulin the high affinity glomerular insulin receptor and the lower affinity tubular insulin receptor have characteristics similar to those of insulin receptors in insulin responsive tissues.

  14. The PI 3-kinase and mTOR signaling pathways are important modulators of epithelial tubule formation.

    PubMed

    Walid, Shereaf; Eisen, Randi; Ratcliffe, Don R; Dai, Kezhi; Hussain, M Mahmood; Ojakian, George K

    2008-08-01

    Using MDCK cells as a model system, evidence is presented demonstrating that the signaling pathways mammalian target of rapamycin (mTOR) and phosphoinositide 3-kinase (PI 3-kinase) play important roles in the regulation of epithelial tubule formation. Incubation of cells with collagen gel overlays induced early (4-8 h) reorganization of cells (epithelial remodeling) into three-dimensional multicellular tubular structures over 24 h. An MDCK cell line stably expressing the PH domain of Akt, a PI 3-kinase downstream effector, coupled to green fluorescent protein (GFP-Akt-PH) was used to determine the distribution of phosphatidyl inositol-3,4,5-P(3) (PIP(3)), a product of PI 3-kinase. GFP-Akt-PH was associated with lateral membranes in control cells. After incubation with collagen gel overlays, GFP-Akt-PH redistributed into the lamellipodia of migrating cells suggesting that PIP(3) plays a role in epithelial remodeling. Using the small molecule inhibitor LY-294002 that inhibits both mTOR and PI 3-kinase, we demonstrated that kinase activity was required for epithelial remodeling, disruption of cell junctions and subsequent modulation of tubule formation. Since the mTOR signaling pathway is downstream of PI 3-kinase, the effects of rapamycin, a specific mTOR inhibitor, on tubule formation were assessed. Rapamycin did not affect epithelial remodeling or GFP-Akt-PH redistribution but inhibited elongated tubule formation that occurred later (24 h) in morphogenesis. These results were further supported by using RNA interference to down-regulate mTOR and inhibit tubule formation. Our studies demonstrate that PI 3-kinase regulates early epithelial remodeling stages while mTOR modulates latter stages of tubule development. PMID:18366086

  15. Deep-apical tubules: dynamic lipid-raft microdomains in the brush-border region of enterocytes.

    PubMed

    Hansen, Gert H; Pedersen, Jens; Niels-Christiansen, Lise-Lotte; Immerdal, Lissi; Danielsen, E Michael

    2003-07-01

    The brush border of small intestinal enterocytes is highly enriched in cholesterol- and glycosphingolipid-containing membrane microdomains, commonly termed as lipid 'rafts'. Functionally, transcytosis of IgA and exocytosis of newly made brush-border proteins in enterocytes occur through apical lipid raft-containing compartments, but little is otherwise known about these raft microdomains. We therefore studied in closer detail apical lipid-raft compartments in enterocytes by immunogold electron microscopy and biochemical analyses. Novel membrane structures, deep-apical tubules, were visualized by the non-permeable surface marker Ruthenium Red in the brush-border region of the cells. The surface-connected tubules were labelled by antibodies to caveolin-1 and the glycolipid asialo G(M1), and they were sensitive to cholesterol depletion by methyl-beta-cyclodextrin, indicating the presence of raft microdomains. Deep-apical tubules were positioned close to the actin rootlets of adjacent microvilli in the terminal web region, which had a diameter of 50-100 nm, and penetrated up to 1 microm into the cytoplasm. Markers for transcytosis, IgA and the polymeric immunoglobulin receptor, as well as the resident brush-border enzyme aminopeptidase N, were present in these deep-apical tubules. We propose that deep-apical tubules are a specialized lipid-raft microdomain in the brush-border region functioning as a hub in membrane trafficking at the brush border. In addition, the sensitivity to cholesterol depletion suggests that deep-apical tubules function as a cell-surface membrane reservoir for cholesterol and for rapid adaptive changes in the size of microvilli at the brush border. PMID:12689332

  16. Lipotoxic disruption of NHE1 interaction with PI(4,5)P2 expedites proximal tubule apoptosis

    PubMed Central

    Khan, Shenaz; Abu Jawdeh, Bassam G.; Goel, Monu; Schilling, William P.; Parker, Mark D.; Puchowicz, Michelle A.; Yadav, Satya P.; Harris, Raymond C.; El-Meanawy, Ashraf; Hoshi, Malcolm; Shinlapawittayatorn, Krekwit; Deschênes, Isabelle; Ficker, Eckhard; Schelling, Jeffrey R.

    2014-01-01

    Chronic kidney disease progression can be predicted based on the degree of tubular atrophy, which is the result of proximal tubule apoptosis. The Na+/H+ exchanger NHE1 regulates proximal tubule cell survival through interaction with phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], but pathophysiologic triggers for NHE1 inactivation are unknown. Because glomerular injury permits proximal tubule luminal exposure and reabsorption of fatty acid/albumin complexes, we hypothesized that accumulation of amphipathic, long-chain acyl-CoA (LC-CoA) metabolites stimulates lipoapoptosis by competing with the structurally similar PI(4,5)P2 for NHE1 binding. Kidneys from mouse models of progressive, albuminuric kidney disease exhibited increased fatty acids, LC-CoAs, and caspase-2–dependent proximal tubule lipoapoptosis. LC-CoAs and the cytosolic domain of NHE1 directly interacted, with an affinity comparable to that of the PI(4,5)P2-NHE1 interaction, and competing LC-CoAs disrupted binding of the NHE1 cytosolic tail to PI(4,5)P2. Inhibition of LC-CoA catabolism reduced NHE1 activity and enhanced apoptosis, whereas inhibition of proximal tubule LC-CoA generation preserved NHE1 activity and protected against apoptosis. Our data indicate that albuminuria/lipiduria enhances lipotoxin delivery to the proximal tubule and accumulation of LC-CoAs contributes to tubular atrophy by severing the NHE1-PI(4,5)P2 interaction, thereby lowering the apoptotic threshold. Furthermore, these data suggest that NHE1 functions as a metabolic sensor for lipotoxicity. PMID:24531551

  17. Microtubules Contribute to Tubule Elongation and Anchoring of Endoplasmic Reticulum, Resulting in High Network Complexity in Arabidopsis1[W][OPEN

    PubMed Central

    Hamada, Takahiro; Ueda, Haruko; Kawase, Takashi; Hara-Nishimura, Ikuko

    2014-01-01

    The endoplasmic reticulum (ER) is a network of tubules and sheet-like structures in eukaryotic cells. Some ER tubules dynamically change their morphology, and others form stable structures. In plants, it has been thought that the ER tubule extension is driven by the actin-myosin machinery. Here, we show that microtubules also contribute to the ER tubule extension with an almost 20-fold slower rate than the actin filament-based ER extension. Treatment with the actin-depolymerizing drug Latrunculin B made it possible to visualize the slow extension of the ER tubules in transgenic Arabidopsis (Arabidopsis thaliana) plants expressing ER-targeted green fluorescent protein. The ER tubules elongated along microtubules in both directions of microtubules, which have a distinct polarity. This feature is similar to the kinesin- or dynein-driven ER tubule extension in animal cells. In contrast to the animal case, ER tubules elongating with the growing microtubule ends were not observed in Arabidopsis. We also found the spots where microtubules are stably colocalized with the ER subdomains during long observations of 1,040 s, suggesting that cortical microtubules contribute to provide ER anchoring points. The anchoring points acted as the branching points of the ER tubules, resulting in the formation of multiway junctions. The density of the ER tubule junction positively correlated with the microtubule density in both elongating cells and mature cells of leaf epidermis, showing the requirement of microtubules for formation of the complex ER network. Taken together, our findings show that plants use microtubules for ER anchoring and ER tubule extension, which establish fine network structures of the ER within the cell. PMID:25367857

  18. Mosquitocidal and Oviposition Repellent Activities of the Extracts of Seaweed Bryopsis pennata on Aedes aegypti and Aedes albopictus.

    PubMed

    Yu, Ke-Xin; Wong, Ching-Lee; Ahmad, Rohani; Jantan, Ibrahim

    2015-01-01

    The ever-increasing threat from infectious diseases and the development of insecticide resistance in mosquito populations drive the global search for new natural insecticides. The aims of this study were to evaluate the mosquitocidal activity of the extracts of seaweed Bryopsis pennata against dengue vectors Aedes aegypti and Aedes albopictus, and determine the seaweed's toxic effect on brine shrimp nauplii (as a non-target organism). In addition, the chemical compositions of the active larvicidal extract and fraction were analyzed by using liquid chromatography-mass spectrometry (LC-MS). Chloroform extract exhibited strong ovicidal activity (with LC50 values of 229.3 and 250.5 µg/mL) and larvicidal activity against Ae. aegypti and Ae. albopictus. The larvicidal potential of chloroform extract was further ascertained when its A7 fraction exhibited strong toxic effect against Ae. aegypti (LC50 = 4.7 µg/mL) and Ae. albopictus (LC50 = 5.3 µg/mL). LC-MS analysis of the chloroform extract gave a tentative identification of 13 compounds; Bis-(3-oxoundecyl) tetrasulfide was identified as the major compound in A7 fraction. Methanol extract showed strong repellent effect against female oviposition, along with weak adulticidal activity against mosquito and weak toxicity against brine shrimp nauplii. The mosquitocidal results of B. pennata suggest further investigation for the development of effective insecticide. PMID:26247928

  19. Effect of housing factors on infestation by Aedes aegypti (L.) and Aedes albopictus Skuse in urban Hanoi City, Vietnam.

    PubMed

    Tsuzuki, Ataru; Sunahara, Toshihiko; Duoc, Vu Trong; Le Nguyen, Hoang; Higa, Yukiko; Phong, Tran Vu; Minakawa, Noboru

    2013-11-01

    To determine the effect of housing factors on infestation with Aedes aegypti (L.) and Aedes albopictus Skuse we conducted an entomological survey and inspection of 267 urban houses in Hanoi City, Vietnam. Two hundred ten pupae and 194 adult Ae. aegypti were collected from 19 and 88 houses, respectively. One hundred eighty-one pupae and 24 adult Ae. albopictus were collected from 21 and 14 houses, respectively. The presence of a private well was associated with increasing infestation with Ae. aegypti adults (p = 0.01) and increased the risk of Ae. aegypti and Ae. albopictus pupal presence (p = 0.04 for Ae. aegypti, p = 0.03 for Ae. albopictus). The presence of an outdoor space in the household premises was associated with a higher risk of Ae. albopictus pupal presence (p = 0.004) and a higher risk of high levels of Ae. albopictus adults (p = 0.01); however, it had no association with infestation with Ae. aegypti. The presence of an air-conditioning unit (p = 0.03) and four or more rooms in the residence (p = 0.02) were negatively and positively associated with the risk for Ae. albopictus presence, respectively. PMID:24450235

  20. The Effects of Interspecific Courtship on the Mating Success of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) Males

    PubMed Central

    Bargielowski, Irka; Blosser, Erik; Lounibos, L. P.

    2015-01-01

    Satyrization, a form of asymmetric reproductive interference, has recently been shown to play a role in competitive displacements of Aedes aegypti (L.) by Aedes albopictus (Skuse). Furthermore, female Ae. aegypti from populations in sympatry with Ae. albopictus have evolved reproductive character displacement and changes in mating behavior to reduce interspecific mating. In this article, we examine evolutionary responses of males to interspecific mating and show that satyrization has also evoked reproductive character displacement in males. We demonstrate that the presence of heterospecific females negatively influences conspecific mating success in male Ae. aegypti, most likely due to misdirected courting or mating efforts, and that males of this species from populations in sympatry with Ae. albopictus have evolved to be less influenced by the presence of heterospecific females than their allopatric counterparts. Conversely, we suggest that the presence of conspecifics may, in some circumstances, increase interspecific mating. This study demonstrates that co-occurrences of these two invasive species may lead to evolution and adaptation of reproductive behaviors to changing circumstances. Understanding the processes driving development of mate choice preferences or avoidance mechanisms may help predict future changes in the distribution and abundance of insect vectors or pests.

  1. Behavioral responses of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus against various synthetic and natural repellent compounds.

    PubMed

    Sathantriphop, Sunaiyana; White, Sabrina A; Achee, Nicole L; Sanguanpong, Unchalee; Chareonviriyaphap, Theeraphap

    2014-12-01

    The behavioral responses of colony populations of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus to four essential oils (citronella, hairy basil, catnip, and vetiver), two standard repellents (DEET and picaridin), and two synthetic pyrethroids (deltamethrin and permethrin) were conducted in the laboratory using an excito-repellency test system. Results revealed that Cx. quinquefasciatus and An. minimus exhibited much stronger behavioral responses to all test compounds (65-98% escape for contact, 21.4-94.4% escape for non-contact) compared to Ae. aegypti (3.7-72.2% escape (contact), 0-31.7% (non-contact)) and Ae. albopictus (3.5-94.4% escape (contact), 11.2-63.7% (non-contact)). In brief, essential oil from vetiver elicited the greatest irritant responses in Cx. quinquefasciatus (96.6%) and An. minimus (96.5%) compared to the other compounds tested. The synthetic pyrethroids caused a stronger contact irritant response (65-97.8% escape) than non-contact repellents (0-50.8% escape for non-contact) across all four mosquito species. Picaridin had the least effect on all mosquito species. Findings from the current study continue to support the screening of essential oils from various plant sources for protective properties against field mosquitoes. PMID:25424262

  2. Age-Stage, Two-Sex Life Table Characteristics of Aedes albopictus and Aedes Aegypti in Penang Island, Malaysia.

    PubMed

    Maimusa, Hamisu A; Ahmad, Abu Hassan; Kassim, Nur Faeza A; Rahim, Junaid

    2016-03-01

    The life table developmental attributes of laboratory colonies of wild strains of Aedes albopictus and Aedes aegypti were analyzed and compared based on the age-stage, two-sex life table. Findings inclusive in this study are: adult preoviposition periods, total preoviposition period, mean intrinsic rate of increase (r), mean finite rate of increase (λ), net reproductive rates (R0), and mean generation time (T). The total preadult development time was 9.47 days for Ae. albopictus and 8.76 days for Ae. aegypti. The life expectancy was 19.01 days for Ae. albopictus and 19.94 days for Ae. aegypti. Mortality occurred mostly during the adult stage. The mean development time for each stage insignificantly correlated with temperature for Ae. albopictus (r  =  -0.208, P > 0.05) and (r  =  -0.312, P > 0.05) for Ae. aegypti. The population parameters suggest that Ae. albopictus and Ae. aegypti populations are r-strategists characterized by a high r, a large R0, and short T. This present study provides the first report to compare the life parameters of Ae. albopictus and Ae. aegypti strains from Penang island, Malaysia. PMID:27105211

  3. Co-occurrence Patterns of the Dengue Vector Aedes aegypti and Aedes mediovitattus, a Dengue Competent Mosquito in Puerto Rico

    PubMed Central

    Little, Eliza; Barrera, Roberto; Seto, Karen C.; Diuk-Wasser, Maria

    2015-01-01

    Aedes aegypti is implicated in dengue transmission in tropical and subtropical urban areas around the world. Ae. aegypti populations are controlled through integrative vector management. However, the efficacy of vector control may be undermined by the presence of alternative, competent species. In Puerto Rico, a native mosquito, Ae. mediovittatus, is a competent dengue vector in laboratory settings and spatially overlaps with Ae. aegypti. It has been proposed that Ae. mediovittatus may act as a dengue reservoir during inter-epidemic periods, perpetuating endemic dengue transmission in rural Puerto Rico. Dengue transmission dynamics may therefore be influenced by the spatial overlap of Ae. mediovittatus, Ae. aegypti, dengue viruses, and humans. We take a landscape epidemiology approach to examine the association between landscape composition and configuration and the distribution of each of these Aedes species and their co-occurrence. We used remotely sensed imagery from a newly launched satellite to map landscape features at very high spatial resolution. We found that the distribution of Ae. aegypti is positively predicted by urban density and by the number of tree patches, Ae. mediovittatus is positively predicted by the number of tree patches, but negatively predicted by large contiguous urban areas, and both species are predicted by urban density and the number of tree patches. This analysis provides evidence that landscape composition and configuration is a surrogate for mosquito community composition, and suggests that mapping landscape structure can be used to inform vector control efforts as well as to inform urban planning. PMID:21989642

  4. Zika virus in Brazil and the danger of infestation by Aedes (Stegomyia) mosquitoes.

    PubMed

    Marcondes, Carlos Brisola; Ximenes, Maria de Fátima Freire de Melo

    2016-02-01

    Zika virus, already widely distributed in Africa and Asia, was recently reported in two Northeastern Brazilian: State of Bahia and State of Rio Grande do Norte, and one Southeastern: State of São Paulo. This finding adds a potentially noxious virus to a list of several other viruses that are widely transmitted by Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus in Brazil. The pathology and epidemiology, including the distribution and vectors associated with Zika virus, are reviewed. This review is focused on viruses transmitted by Aedes (Stegomyia) mosquitoes, including dengue, Chikungunya, Zika, Mayaro, and yellow fever virus, to emphasize the risks of occurrence for these arboviruses in Brazil and neighboring countries. Other species of Aedes (Stegomyia) are discussed, emphasizing their involvement in arbovirus transmission and the possibility of adaptation to environments modified by human activities and introduction in Brazil. PMID:26689277

  5. Geographical distribution of the Aedes Triseriatus Group (Diptera: Culicidae) in Mexico.

    PubMed

    Sánchez-Trinidad, Adelfo; Ordoñez-Sánchez, Félix; Valdes-Perezgasga, Ma Teresa; Sánchez-Ramos, Francisco J; Zavortink, Thomas J; Cortés-Guzmán, Antonio J; Ortega-Morales, Aldo I

    2014-06-01

    Aedes brelandi Zavortink is reported for the first time outside of the United States, where it has been found in northern and central parts of Mexico. Ae. triseriatus (Say) is reported in northern and central Mexico and Ae. zoosophus Dyar and Knab is recorded in southern Mexico. Collection records for these species in northern, central, and southern Mexico showing the current distribution of the Aedes Triseriatus Group are included. PMID:24820565

  6. Regulation of K transport in a mathematical model of the cortical collecting tubule.

    PubMed

    Strieter, J; Weinstein, A M; Giebisch, G; Stephenson, J L

    1992-12-01

    The effect of luminal flow rate and peritubular pH on Na and K transport is investigated in a mathematical model of the rabbit cortical collecting tubule. The model is used to simulate a 0.4-cm segment of tubule comprised of principal cell, alpha- and beta-intercalated cells, and lateral interspace. Calculations produce luminal profiles of Na, K, Cl, HCO3, and phosphate, as well as of electrical potential and pH. Parameter sets are developed that permit representation of both unstimulated and deoxycorticosterone acetate-stimulated tubules. A series of simulations is performed in which initial luminal flow rate is varied over the range of values between 0.1 and 30 nl/min. A marked flow-dependent enhancement of Na reabsorption and K secretion is seen, especially at lower flows, while Cl and HCO3 transport remain relatively constant. In experimental studies, it has been observed that metabolic alkalosis stimulates and metabolic acidosis inhibits K secretion, while leaving Na transport relatively unaffected [B. A. Stanton and G. Giebisch. Am. J. Physiol. 242 (Renal Fluid Electrolyte Physiol. 11): F544-F551, 1982; K. Tabei, S. Muto, Y. Ando, Y. Sakairi, and Y. Asano. J. Am. Soc. Nephrol. 1: 693, 1990; and K. Tabei, S. Muto, H. Furuya, and Y. Asano. J. Am. Soc. Nephrol. 2: 752, 1991]. Model calculations indicate that, when ion permeabilities are fixed and not dependent on pH, the impact of peritubular HCO3 on K secretion cannot be simulated. When junctional Cl permeability decreases with increasing interspace pH (E. M. Wright and J. M. Diamond. Biochim. Biophys. Acta 163: 57-74, 1968) in the model, there is a marked stimulation of K secretion with alkalosis and inhibition with acidosis. Furthermore, inclusion of a pH-dependent apical Na permeability [L. G. Palmer and G. Frindt. Am. J. Physiol. 253 (Renal Fluid Electrolyte Physiol. 22): F333-F339, 1987] that increases with increasing principal cell pH significantly reduces the change in Na+ reabsorption seen with the p

  7. The effect of dentine location and tubule orientation on the bond strengths between resin and dentine.

    PubMed

    Phrukkanon, S; Burrow, M F; Tyas, M J

    1999-05-01

    This study determined the influence of dentine structure on the micro-tensile bond strengths between resin and dentine of two different dentine adhesive systems (Single Bond, 3M Dental Products, St Paul, MN; MF-102 (experimental self-etching primer), GC Corporation, Tokyo, Japan). The study was separated into two main parts: bond strength measurement and investigation of the bonding interface. Twenty-two human premolars were used for the bond strength measurement. Each tooth was cut vertically, separating the tooth into mesio-distal halves. One half of the tooth was used to bond to a surface perpendicular to the dentinal tubules and other half to bond to a surface parallel to the tubules. For each half, six locations of dentine were bonded. Each material was used in accordance to the manufacturer's directions. Cylindrical hourglass-shaped specimens of 1.2 mm diameter at the bonded interface were manufactured. The bonds were stressed in tension at a crosshead speed of 1 mm/min. Mean bond strengths were compared using LSD, one-way ANOVA, and Student's t-test. The fractured surfaces were examined under a scanning electron microscope, and the frequency of fracture modes was compared using the Kruskal-Wallis and Mann-Whitney U tests. For the investigation of the bonded interface, four teeth were prepared by the same procedure used for the bond test specimens. The bonded interfaces were observed after an acid-base treatment or fracturing across the bonded interface, prior to investigation with a field-emission scanning electron microscope. For Single Bond, the bond strengths for mid-root dentine were significantly lower than for other locations (p < 0.05). For MF-102, there was no significant difference for all locations (p > 0.05). MF-102 bonded well to all locations of dentine while Single Bond showed a porous zone at the base of the hybrid layer. The bonds were not influenced by tubule orientation. The results indicate that the bond for Single Bond may be affected by

  8. The effects of simulated microgravity on the seminiferous tubules of rats

    NASA Astrophysics Data System (ADS)

    Forsman, Allan D.

    2012-02-01

    Space flight has been shown to have many adverse effects on various systems throughout the body. Because the opportunity to place research animals on board a Space Shuttle or the International Space Station is infrequent, various techniques have been designed to simulate the effects of microgravity in Earth based laboratories. A commonly used technique is known as antiorthostatic suspension, also often referred to as hind limb suspension. In this technique the hind portion of the animal is raised so that its hind limbs are non-weight bearing. This places the animal in roughly a 30° head down tilt position. This results in cephalic fluid shifts similar to those seen in actual space flight. This technique has also been shown to mimic other physiological parameters that are affected during space flight. This study examined testicular tissue from rats subjected to a 7 day antiorthostatic suspension. This tissue was acquired through a tissue sharing program and some of the experimental animals were injected with Interleukin 1 receptor antagonist (IL-1ra) which was hoped to ameliorate some of the effects of antiorthostatic suspension. The injection of IL-1ra was not expected to have any effect on testicular tissue, however this tissue was included in the morphological and statistical analysis to conduct a more complete study. All tissues were embedded in paraffin, sectioned, and stained using standard H&E staining. The tissue was then qualitatively ranked according to the "health" of the seminiferous tubules. Our findings indicate that 7 days of antiorthostatic suspension had adverse effects on the tissue that comprises the walls of the seminiferous tubules. It has long been known that antiorthostatic suspension has deleterious effects on testicular tissue, however this research indicates that these effects occur much faster than indicated by previous researchers. This is a significant finding because it indicates that meaningful earth based studies in this area can be

  9. Albumin absorption and catabolism by isolated perfused proximal convoluted tubules of the rabbit.

    PubMed Central

    Park, C H; Maack, T

    1984-01-01

    Overall characteristics and kinetics of tubular absorption of albumin (Alb) were studied in isolated perfused proximal convoluted tubules of the rabbit. The fate of absorbed Alb was determined in tubules perfused with low [Alb]. Alb was labeled with tritium by reductive methylation ( [3H3C]Alb). At [Alb] = 0.03 mg/ml, approximately 80% of the absorbed [3H3C]Alb was released to the peritubular bathing solution as catabolic products. Transcellular transport of intact [3H3C]Alb was negligible. Iodoacetate (IAA, 4 mM) inhibited albumin absorption (JAlb) by greater than 95% and fluid reabsorption (JV) by 55%. At [Alb] = 0.1 mg/ml the absorption rate of a derivatized cationic Alb (pI = 8.4) was fivefold greater (P less than 0.01) than that of anionic Alb. Higher cationic [Alb] had deleterious effects on tubular functions. Overall Alb absorption was of high capacity and low affinity (JmaxAlb = 3.7 ng/min per mm tubule length, apparent Michaelis constant (Km) = 1.2 mg/ml). A low capacity system that saturates at near physiological loads was also detected (JmaxAlb = 0.064 ng/min per mm, apparent Km = 0.031 mg/ml). High [Alb] did not alter the rate of endocytic vesicle formation as determined by the tubular uptake of [14C]inulin. Results show that Alb absorption is a saturable process that is inhibited by high IAA concentrations and is affected by the charge of the protein. Absorbed Alb is hydrolyzed by tubular cells and catabolic products are readily released to the peritubular side. The dual kinetics of Alb absorption may be due to a combination of adsorptive endocytosis (low capacity system) and fluid endocytosis of albumin aggregates (high capacity system). Results indicate that albuminuria occurs much before albumin absorption is saturated. The kinetic characteristics of the process of tubular absorption of albumin helps to explain the concomitance of albuminuria, increased renal catabolic rates of albumin, and renal cell deposition of protein absorption droplets in

  10. Risk Factors for the Presence of Aedes aegypti and Aedes albopictus in Domestic Water-Holding Containers in Areas Impacted by the Nam Theun 2 Hydroelectric Project, Laos

    PubMed Central

    Hiscox, Alexandra; Kaye, Angela; Vongphayloth, Khamsing; Banks, Ian; Piffer, Michele; Khammanithong, Phasouk; Sananikhom, Pany; Kaul, Surinder; Hill, Nigel; Lindsay, Steven W.; Brey, Paul T.

    2013-01-01

    We assessed risk factors for vectors of dengue and chikungunya viruses near a new hydroelectric project, Nam Theun 2, in Laos. Immature stages of Aedes aegypti were found only in sites within 40 km of the urban provincial capital, but Aedes albopictus was found throughout. Aedes aegypti pupae were most common in water storage jars (odds ratio [OR] = 4.72) and tires (OR = 2.99), and Ae. albopictus pupae were associated with tires in 2009 (OR = 10.87) and drums, tires, and jars in 2010 (drums OR = 3.05; tires OR = 3.45, jars OR = 6.59). Compared with water storage vessels, containers used for hygiene, cooking, and drinking were 80% less likely to harbor Ae. albopictus pupae in 2010 (OR = 0.20), and discarded waste was associated with a 3.64 increased odds of infestation. Vector control efforts should focus on source reduction of water storage containers, particularly concrete jars and tires. PMID:23458958

  11. Self-organization of engineered epithelial tubules by differential cellular motility

    SciTech Connect

    Mori, Hidetoshi; Gjorevski, Nikolce; Inman, Jamie L; Bissell, Mina J; Nelson, Celeste M

    2009-02-04

    Patterning of developing tissues arises from a number of mechanisms, including cell shape change, cell proliferation, and cell sorting from differential cohesion or tension. Here, we reveal that differences in cell motility can also lead to cell sorting within tissues. Using mosaic engineered mammary epithelial tubules, we found that cells sorted depending on their expression level of the membrane-anchored collagenase matrix metalloproteinase (MMP)-14. These rearrangements were independent of the catalytic activity of MMP14 but absolutely required the hemopexin domain. We describe a signaling cascade downstream of MMP14 through Rho kinase that allows cells to sort within the model tissues. Cell speed and persistence time were enhanced by MMP14 expression, but only the latter motility parameter was required for sorting. These results indicate that differential directional persistence can give rise to patterns within model developing tissues.

  12. Arabidopsis dynamin-related protein 1A polymers bind, but do not tubulate, liposomes

    SciTech Connect

    Backues, Steven K.; Bednarek, Sebastian Y.

    2010-03-19

    The Arabidopsis dynamin-related protein 1A (AtDRP1A) is involved in endocytosis and cell plate maturation in Arabidopsis. Unlike dynamin, AtDRP1A does not have any recognized membrane binding or protein-protein interaction domains. We report that GTPase active AtDRP1A purified from Escherichia coli as a fusion to maltose binding protein forms homopolymers visible by negative staining electron microscopy. These polymers interact with protein-free liposomes whose lipid composition mimics that of the inner leaflet of the Arabidopsis plasma membrane, suggesting that lipid-binding may play a role in AtDRP1A function. However, AtDRP1A polymers do not appear to assemble and disassemble in a dynamic fashion and do not have the ability to tubulate liposomes in vitro, suggesting that additional factors or modifications are necessary for AtDRP1A's in vivo function.

  13. Effect of nutritional substrate on sulfolipids metabolic turnover in isolated renal tubules from rat

    PubMed Central

    NAGAI, Ken-ichi; TADANO-ARITOMI, Keiko; NIIMURA, Yukio; ISHIZUKA, Ineo

    2008-01-01

    Effects of a glycolytic (glucose) and a gluconeogenic renal nutritional substrate (glutamine) on metabolic turnover of sulfolipids, determined as [35S]sulfate incorporation, were compared in renal tubules prepared from well-fed rats. The results showed that the effects of glucose and glutamine, at nearly physiological serum concentration, are quite contrary to each other. Glucose increased the turnover rates of relatively long chain ganglio-series sulfoglycolipids (Gg3Cer II3-sulfate and Gg4Cer II3,IV3-bis-sulfate) (1.7 to 2.4-fold), but not of cholesterol 3-sulfate (0.9-fold). In contrast, glutamine accelerated the turnover rates of relatively short chain sulfoglycolipids (glucosyl sulfatide, galactosyl sulfatide and lactosyl sulfatide) (1.3 to 2.7-fold), as well as cholesterol 3-sulfate (2.4-fold). The possible mechanism which causes these marked differences is also discussed. PMID:18941285

  14. An ancestral luciferase in the Malpighi tubules of a non-bioluminescent beetle!

    PubMed

    Viviani, V R; Prado, R A; Arnoldi, F C G; Abdalla, F C

    2009-01-01

    The evolutionary origin of beetle bioluminescence is enigmatic. Previously, weak luciferase activity was found in the non-bioluminescent larvae of Tenebrio molitor (Coleoptera: Tenebrionidae), but the detailed tissular origin and identity of the luciferase-like enzyme remained unknown. Using a closely related giant mealworm, Zophobas morio, here we show that the luciferase-like enzyme is located in the Malpighi tubules. cDNA cloning of this luciferase like enzyme, showed that it is a short AMP-ligase with weak luciferase activity which diverged long ago from beetle luciferases. The results indicate that the potential for bioluminescence in AMP-ligases is very ancient and provide a first reasonable protoluciferase model to investigate the origin and evolution of beetle luciferases. PMID:19247530

  15. Caulimoviridae tubule-guided transport is dictated by movement protein properties.

    PubMed

    Sánchez-Navarro, Jesús; Fajardo, Thor; Zicca, Stefania; Pallás, Vicente; Stavolone, Livia

    2010-04-01

    Plant viruses move through plasmodesmata (PD) either as nucleoprotein complexes (NPCs) or as tubule-guided encapsidated particles with the help of movement proteins (MPs). To explore how and why MPs specialize in one mechanism or the other, we tested the exchangeability of MPs encoded by DNA and RNA virus genomes by means of an engineered alfalfa mosaic virus (AMV) system. We show that Caulimoviridae (DNA genome virus) MPs are competent for RNA virus particle transport but are unable to mediate NPC movement, and we discuss this restriction in terms of the evolution of DNA virus MPs as a means of mediating DNA viral genome entry into the RNA-trafficking PD pathway. PMID:20130061

  16. Aedes aegypti (Diptera: Culicidae) in Mauritania: First Report on the Presence of the Arbovirus Mosquito Vector in Nouakchott.

    PubMed

    Mint Lekweiry, Khadijetou; Ould Ahmedou Salem, Mohamed Salem; Ould Brahim, Khyarhoum; Ould Lemrabott, Mohamed Aly; Brengues, Cécile; Faye, Ousmane; Simard, Frédéric; Ould Mohamed Salem Boukhary, Ali

    2015-07-01

    Aedes aegypti L. (Diptera: Culicidae) is a major vector of yellow fever, dengue, and chikungunya viruses throughout tropical and subtropical areas of the world. Although the southernmost part of Mauritania along the Senegal river has long been recognized at risk of yellow fever transmission, Aedes spp. mosquitoes had never been reported northwards in Mauritania. Here, we report the first observation of Aedes aegypti aegypti (L.) and Aedes (Ochlerotatus) caspius (Pallas, 1771) in the capital city, Nouakchott. We describe the development sites in which larvae of the two species were found, drawing attention to the risk for emergence of arbovirus transmission in the city. PMID:26335483

  17. A primary culture of distal convoluted tubules expressing functional thiazide-sensitive NaCl transport.

    PubMed

    Markadieu, Nicolas; San-Cristobal, Pedro; Nair, Anil V; Verkaart, Sjoerd; Lenssen, Ellen; Tudpor, Kukiat; van Zeeland, Femke; Loffing, Johannes; Bindels, René J M; Hoenderop, Joost G J

    2012-09-15

    Studying the molecular regulation of the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC) is important for understanding how the kidney contributes to blood pressure regulation. Until now, a native mammalian cell model to investigate this transporter remained unknown. Our aim here is to establish, for the first time, a primary distal convoluted tubule (DCT) cell culture exhibiting transcellular thiazide-sensitive Na(+) transport. Because parvalbumin (PV) is primarily expressed in the DCT, where it colocalizes with NCC, kidneys from mice expressing enhanced green-fluorescent protein (eGFP) under the PV gene promoter (PV-eGFP-mice) were employed. The Complex Object Parametric Analyzer and Sorter (COPAS) was used to sort fluorescent PV-positive tubules from these kidneys, which were then seeded onto permeable supports. After 6 days, DCT cell monolayers developed transepithelial resistance values of 630 ± 33 Ω·cm(2). The monolayers also established opposing transcellular concentration gradients of Na(+) and K(+). Radioactive (22)Na(+) flux experiments showed a net apical-to-basolateral thiazide-sensitive Na(+) transport across the monolayers. Both hypotonic low-chloride medium and 1 μM angiotensin II increased this (22)Na(+) transport significantly by four times, which could be totally blocked by 100 μM hydrochlorothiazide. Angiotensin II-stimulated (22)Na(+) transport was also inhibited by 1 μM losartan. Furthermore, NCC present in the DCT monolayers was detected by immunoblot and immunocytochemistry studies. In conclusion, a murine primary DCT culture was established which expresses functional thiazide-sensitive Na(+)-Cl(-) transport. PMID:22759396

  18. Localization of the calcium-regulated citrate transport process in proximal tubule cells.

    PubMed

    Hering-Smith, Kathleen S; Mao, Weibo; Schiro, Faith R; Coleman-Barnett, Joycelynn; Pajor, Ana M; Hamm, L Lee

    2014-06-01

    Urinary citrate is an important inhibitor of calcium-stone formation. Most of the citrate reabsorption in the proximal tubule is thought to occur via a dicarboxylate transporter NaDC1 located in the apical membrane. OK cells, an established opossum kidney proximal tubule cell line, transport citrate but the characteristics change with extracellular calcium such that low calcium solutions stimulate total citrate transport as well as increase the apparent affinity for transport. The present studies address several fundamental properties of this novel process: the polarity of the transport process, the location of the calcium-sensitivity and whether NaDC1 is present in OK cells. OK cells grown on permeable supports exhibited apical >basolateral citrate transport. Apical transport of both citrate and succinate was sensitive to extracellular calcium whereas basolateral transport was not. Apical calcium, rather than basolateral, was the predominant determinant of changes in transport. Also 2,3-dimethylsuccinate, previously identified as an inhibitor of basolateral dicarboxylate transport, inhibited apical citrate uptake. Although the calcium-sensitive transport process in OK cells is functionally not typical NaDC1, NaDC1 is present in OK cells by Western blot and PCR. By immunolocalization studies, NaDC1 was predominantly located in discrete apical membrane or subapical areas. However, by biotinylation, apical NaDC1 decreases in the apical membrane with lowering calcium. In sum, OK cells express a calcium-sensitive/regulated dicarboxylate process at the apical membrane which responds to variations in apical calcium. Despite the functional differences of this process compared to NaDC1, NaDC1 is present in these cells, but predominantly in subapical vesicles. PMID:24652587

  19. Akt Links Insulin Signaling to Albumin Endocytosis in Proximal Tubule Epithelial Cells

    PubMed Central

    Coffey, Sam; Costacou, Tina; Orchard, Trevor; Erkan, Elif

    2015-01-01

    Diabetes mellitus (DM) has become an epidemic, causing a significant decline in quality of life of individuals due to its multisystem involvement. Kidney is an important target organ in DM accounting for the majority of patients requiring renal replacement therapy at dialysis units. Microalbuminuria (MA) has been a valuable tool to predict end-organ damage in DM but its low sensitivity has driven research efforts to seek other alternatives. Albumin is taken up by albumin receptors, megalin and cubilin in the proximal tubule epithelial cells. We demonstrated that insulin at physiological concentrations induce albumin endocytosis through activation of protein kinase B (Akt) in proximal tubule epithelial cells. Inhibition of Akt by a phosphorylation deficient construct abrogated insulin induced albumin endocytosis suggesting a role for Akt in insulin-induced albumin endocytosis. Furthermore we demonstrated a novel interaction between Akt substrate 160kDa (AS160) and cytoplasmic tail of megalin. Mice with type 1 DM (T1D) displayed decreased Akt, megalin, cubilin and AS160 expression in their kidneys in association with urinary cubilin shedding preceding significant MA. Patients with T1D who have developed MA in the EDC (The Pittsburgh Epidemiology of Diabetes Complications) study demonstrated urinary cubilin shedding prior to development of MA. We hypothesize that perturbed insulin-Akt cascade in DM leads to alterations in trafficking of megalin and cubilin, which results in urinary cubilin shedding as a prelude to MA in early diabetic nephropathy. We propose that utilization of urinary cubilin shedding, as a urinary biomarker, will allow us to detect and intervene in diabetic nephropathy (DN) at an earlier stage. PMID:26465605

  20. Short-term nonpressor angiotensin II infusion stimulates sodium transporters in proximal tubule and distal nephron

    PubMed Central

    Nguyen, Mien T X; Han, Jiyang; Ralph, Donna L; Veiras, Luciana C; McDonough, Alicia A

    2015-01-01

    In Sprague Dawley rats, 2-week angiotensin II (AngII) infusion increases Na+ transporter abundance and activation from cortical thick ascending loop of Henle (TALH) to medullary collecting duct (CD) and raises blood pressure associated with a pressure natriuresis, accompanied by depressed Na+ transporter abundance and activation from proximal tubule (PT) through medullary TALH. This study tests the hypothesis that early during AngII infusion, before blood pressure raises, Na+ transporters’ abundance and activation increase all along the nephron. Male Sprague Dawley rats were infused via osmotic minipumps with a subpressor dose of AngII (200 ng/kg/min) or vehicle for 3 days. Overnight urine was collected in metabolic cages and sodium transporters’ abundance and phosphorylation were determined by immunoblotting homogenates of renal cortex and medulla. There were no significant differences in body weight gain, overnight urine volume, urinary Na+ and K+ excretion, or rate of excretion of a saline challenge between AngII and vehicle infused rats. The 3-day nonpressor AngII infusion significantly increased the abundance of PT Na+/H+ exchanger 3 (NHE3), cortical TALH Na-K-2Cl cotransporter 2 (NKCC2), distal convoluted tubule (DCT) Na-Cl cotransporter (NCC), and cortical CD ENaC subunits. Additionally, phosphorylation of cortical NKCC2, NCC, and STE20/SPS1-related proline–alanine-rich kinase (SPAK) were increased; medullary NKCC2 and SPAK were not altered. In conclusion, 3-day AngII infusion provokes PT NHE3 accumulation as well as NKCC2, NCC, and SPAK accumulation and activation in a prehypertensive phase before evidence for intrarenal angiotensinogen accumulation. PMID:26347505

  1. Urinary and proximal tubule acidification during reduction of renal blood flow in the rat.

    PubMed Central

    Jaramillo-Juárez, F; Aires, M M; Malnic, G

    1990-01-01

    1. The effects of reduction in renal blood flow (RBF) on urinary acidification and proximal tubule H+ ion secretion were studied after partial aortic clamping in rats. 2. Acute reduction of the renal perfusion pressure (from 109 +/- 3.88 to 77.4 +/- 1.05 mmHg) decreased both inulin and PAH (p-aminohippurate) clearances to about one-third of their control values. Absolute levels of urinary sodium excretion also decreased markedly, but fractional sodium excretion did not change significantly. 3. Urine pH and bicarbonate levels were not affected, but titratable acidity increased significantly from 0.12 +/- 0.011 to 0.25 +/- 0.042 muequiv min-1 ml-1 glomerular filtration rate (GFR). During aortic clamping, cortical PCO2 as determined by means of Severinghaus microelectrodes was reduced by a mean value of 7.0 +/- 1.5 mmHg. 4. Proximal tubule acidification kinetics were studied by stationary microperfusion techniques in which the time course of pH changes was monitored by pH microelectrodes. Steady-state pH fell from a mean control value of 6.77 +/- 0.03 to 6.65 +/- 0.02, and stationary bicarbonate concentrations from 4.70 +/- 0.27 to 2.84 +/- 0.18 mM. Acidification half-time decreased from 5.07 +/- 0.30 to 4.39 +/- 0.19 s, and net bicarbonate reabsorption increased from 1.63 +/- 0.14 to 1.99 +/- 0.12 nmol cm-2 s-1, these changes being statistically significant. 5. The experiments demonstrate that both overall acid excretion and proximal acid secretion are not compromised by a large decrease of RBF to about one-third of the control value; titratable acid excretion and proximal net bicarbonate reabsorption were even moderately increased under these conditions. PMID:2348400

  2. Akt Links Insulin Signaling to Albumin Endocytosis in Proximal Tubule Epithelial Cells.

    PubMed

    Coffey, Sam; Costacou, Tina; Orchard, Trevor; Erkan, Elif

    2015-01-01

    Diabetes mellitus (DM) has become an epidemic, causing a significant decline in quality of life of individuals due to its multisystem involvement. Kidney is an important target organ in DM accounting for the majority of patients requiring renal replacement therapy at dialysis units. Microalbuminuria (MA) has been a valuable tool to predict end-organ damage in DM but its low sensitivity has driven research efforts to seek other alternatives. Albumin is taken up by albumin receptors, megalin and cubilin in the proximal tubule epithelial cells. We demonstrated that insulin at physiological concentrations induce albumin endocytosis through activation of protein kinase B (Akt) in proximal tubule epithelial cells. Inhibition of Akt by a phosphorylation deficient construct abrogated insulin induced albumin endocytosis suggesting a role for Akt in insulin-induced albumin endocytosis. Furthermore we demonstrated a novel interaction between Akt substrate 160kDa (AS160) and cytoplasmic tail of megalin. Mice with type 1 DM (T1D) displayed decreased Akt, megalin, cubilin and AS160 expression in their kidneys in association with urinary cubilin shedding preceding significant MA. Patients with T1D who have developed MA in the EDC (The Pittsburgh Epidemiology of Diabetes Complications) study demonstrated urinary cubilin shedding prior to development of MA. We hypothesize that perturbed insulin-Akt cascade in DM leads to alterations in trafficking of megalin and cubilin, which results in urinary cubilin shedding as a prelude to MA in early diabetic nephropathy. We propose that utilization of urinary cubilin shedding, as a urinary biomarker, will allow us to detect and intervene in diabetic nephropathy (DN) at an earlier stage. PMID:26465605

  3. cAMP-binding proteins in medullary tubules from rat kidney: effect of ADH

    SciTech Connect

    Gapstur, S.M.; Homma, S.; Dousa, T.P.

    1988-08-01

    Little is known of the regulatory steps in the cellular action of vasopressin (AVP) on the renal epithelium, subsequent to the cAMP generation. We studied cAMP-binding proteins in the medullary collecting tubule (MCT) and the thick ascending limb of Henle's loop (MTAL) microdissected from the rat kidney by use of photoaffinity labeling. Microdissected tubules were homogenized and photoaffinity labeled by incubation with 1 microM 32P-labeled 8-azido-adenosine 3',5'-cyclic monophosphate (N3-8-(32P)-cAMP); the incorporated 32P was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. Both in MCT and MTAL preparations, the analyses showed incorporation of N3-8-(32P)cAMP into two bands (Mr = 49,000 and Mr = 55,000) that comigrated with standards of the cAMP-dependent protein kinase regulatory subunits RI and RII. In MCT, most of the 32P (80%) was incorporated into RI, whereas in MTAL the 32P incorporated into RI and RII was equivalent. When freshly dissected MCT segments were incubated with 10(-12)-10(-6) M AVP, the subsequent photoaffinity labeling of RI with N3-8-(32P)cAMP was markedly diminished in a dose-dependent manner compared with controls. Our results suggest that cAMP binds in MCT and MTAL to regulatory subunits RI and RII of cAMP-dependent protein kinase. However, in MCT the dominant type of cAMP-dependent protein kinase appears to be type I. The outlined procedure is suitable to indirectly measure the occupancy of RI by endogenous cAMP generated in MCT cells in response to physiological levels (10(-12) M) of AVP.

  4. The global compendium of Aedes aegypti and Ae. albopictus occurrence

    PubMed Central

    Kraemer, Moritz U. G.; Sinka, Marianne E.; Duda, Kirsten A.; Mylne, Adrian; Shearer, Freya M.; Brady, Oliver J.; Messina, Jane P.; Barker, Christopher M.; Moore, Chester G.; Carvalho, Roberta G.; Coelho, Giovanini E.; Van Bortel, Wim; Hendrickx, Guy; Schaffner, Francis; Wint, G. R. William; Elyazar, Iqbal R. F.; Teng, Hwa-Jen; Hay, Simon I.

    2015-01-01

    Aedes aegypti and Ae. albopictus are the main vectors transmitting dengue and chikungunya viruses. Despite being pathogens of global public health importance, knowledge of their vectors’ global distribution remains patchy and sparse. A global geographic database of known occurrences of Ae. aegypti and Ae. albopictus between 1960 and 2014 was compiled. Herein we present the database, which comprises occurrence data linked to point or polygon locations, derived from peer-reviewed literature and unpublished studies including national entomological surveys and expert networks. We describe all data collection processes, as well as geo-positioning methods, database management and quality-control procedures. This is the first comprehensive global database of Ae. aegypti and Ae. albopictus occurrence, consisting of 19,930 and 22,137 geo-positioned occurrence records respectively. Both datasets can be used for a variety of mapping and spatial analyses of the vectors and, by inference, the diseases they transmit. PMID:26175912

  5. Cytotoxicity of piperamides towards Aedes aegypti (Diptera: Culicidae).

    PubMed

    Maleck, Marise; Ferreira, Bruna; Mallet, Jacenir; Guimarães, Anthony; Kato, Massuo

    2014-03-01

    The effectiveness of the amides piplartine and piperlonguminine isolated from Piper species for controlling L3 and L4 of Aedes aegypti (L.) was assessed through bioassays at concentrations ranging from 1 to 300 g/l ml. Piplartine reduced the mosquito development period and caused larval mortality only at concentrations > 100 microg/ml, whereas piperlonguminine resulted in an extended period of mosquito development (10 microg/ml) and caused 100% larval mortality (30 microg/ml) within 24 h. The toxicity and cytotoxic effects of piperlonguminine on epithelial cells of the digestive system of Ae. aegypti were viewed using transmission electron microscopy, which indicated vacuolization of cytoplasm, mitochondrial swelling and leaking of nuclear material. Piperlonguminine was the more effective amide, showing toxic activity with LD50 of approximately 12 microg/ml against the larvae of Ae. aegypti. PMID:24724297

  6. Plaque Production by Arboviruses in Singh's Aedes albopictus Cells

    PubMed Central

    Yunker, C. E.; Cory, J.

    1975-01-01

    We report plaquing tests of 124 virus strains, mostly arboviruses of 21 serological groups, in Singh's line of Aedes albopictus cells. Thirty of these plaqued; all were arboviruses of six groups and were known or presumed to be mosquito borne. Failing to plaque were 86 strains of arboviruses, mostly tick borne, two strains of insect pathogens, and six animal viruses not classified as arboviruses. Among mosquito-borne agents, plaquing ability appeared related to serological classification. California group and most A-group viruses failed to plaque, but nearly all members of B and Bunyamwera groups readily plaqued. Within serological group B, 14 of 16 mosquito-borne agents plaqued, but none of 13 tick-borne or vector-unassociated viruses did so. Some implications of these results for recognition and classification of arboviruses are discussed. Images PMID:234160

  7. Larvicidal activity of Tagetes minuta (marigold) toward Aedes aegypti.

    PubMed

    Green, M M; Singer, J M; Sutherland, D J; Hibben, C R

    1991-06-01

    The steam distilled oils of 3 species of marigold, Tagetes patula, T. erecta and T. minuta, were tested for larvicidal activity toward third instar Aedes aegypti; activity at 10 ppm was demonstrated only for T. minuta. The larvicidal property of the whole oil dispersed in water persisted for at least 9 days. The terpene, ocimenone, which is a part of the whole oil, was found to be larvicidal only at a higher concentration than the whole oil and to lose its activity within 24 h after dispersal in water. These results suggest a potential utilization of oil of T. minuta or its components for the control of Ae. aegypti and other species of mosquitoes. PMID:1895085

  8. Genome sequence of Aedes aegypti, a major arbovirus vector.

    PubMed

    Nene, Vishvanath; Wortman, Jennifer R; Lawson, Daniel; Haas, Brian; Kodira, Chinnappa; Tu, Zhijian Jake; Loftus, Brendan; Xi, Zhiyong; Megy, Karyn; Grabherr, Manfred; Ren, Quinghu; Zdobnov, Evgeny M; Lobo, Neil F; Campbell, Kathryn S; Brown, Susan E; Bonaldo, Maria F; Zhu, Jingsong; Sinkins, Steven P; Hogenkamp, David G; Amedeo, Paolo; Arensburger, Peter; Atkinson, Peter W; Bidwell, Shelby; Biedler, Jim; Birney, Ewan; Bruggner, Robert V; Costas, Javier; Coy, Monique R; Crabtree, Jonathan; Crawford, Matt; Debruyn, Becky; Decaprio, David; Eiglmeier, Karin; Eisenstadt, Eric; El-Dorry, Hamza; Gelbart, William M; Gomes, Suely L; Hammond, Martin; Hannick, Linda I; Hogan, James R; Holmes, Michael H; Jaffe, David; Johnston, J Spencer; Kennedy, Ryan C; Koo, Hean; Kravitz, Saul; Kriventseva, Evgenia V; Kulp, David; Labutti, Kurt; Lee, Eduardo; Li, Song; Lovin, Diane D; Mao, Chunhong; Mauceli, Evan; Menck, Carlos F M; Miller, Jason R; Montgomery, Philip; Mori, Akio; Nascimento, Ana L; Naveira, Horacio F; Nusbaum, Chad; O'leary, Sinéad; Orvis, Joshua; Pertea, Mihaela; Quesneville, Hadi; Reidenbach, Kyanne R; Rogers, Yu-Hui; Roth, Charles W; Schneider, Jennifer R; Schatz, Michael; Shumway, Martin; Stanke, Mario; Stinson, Eric O; Tubio, Jose M C; Vanzee, Janice P; Verjovski-Almeida, Sergio; Werner, Doreen; White, Owen; Wyder, Stefan; Zeng, Qiandong; Zhao, Qi; Zhao, Yongmei; Hill, Catherine A; Raikhel, Alexander S; Soares, Marcelo B; Knudson, Dennis L; Lee, Norman H; Galagan, James; Salzberg, Steven L; Paulsen, Ian T; Dimopoulos, George; Collins, Frank H; Birren, Bruce; Fraser-Liggett, Claire M; Severson, David W

    2007-06-22

    We present a draft sequence of the genome of Aedes aegypti, the primary vector for yellow fever and dengue fever, which at approximately 1376 million base pairs is about 5 times the size of the genome of the malaria vector Anopheles gambiae. Nearly 50% of the Ae. aegypti genome consists of transposable elements. These contribute to a factor of approximately 4 to 6 increase in average gene length and in sizes of intergenic regions relative to An. gambiae and Drosophila melanogaster. Nonetheless, chromosomal synteny is generally maintained among all three insects, although conservation of orthologous gene order is higher (by a factor of approximately 2) between the mosquito species than between either of them and the fruit fly. An increase in genes encoding odorant binding, cytochrome P450, and cuticle domains relative to An. gambiae suggests that members of these protein families underpin some of the biological differences between the two mosquito species. PMID:17510324

  9. Larvicidal activity of Tagetes erecta against Aedes aegypti.

    PubMed

    Marques, Márcia M M; Morais, Selene M; Vieira, Icaro G P; Vieira, Mariano G S; Raquel, Ana; Silva, A; De Almeida, Raimundo Rafael; Guedes, Maria Izabel F

    2011-06-01

    The aim of this study was to evaluate the activity of essential oil from Tagetes erecta against 3rd instars of Aedes aegypti and to determine the amounts of larvicidal thiophenes in all plant tissues. The oil obtained by steam distillation and analyzed by gas chromatography/mass spectrometry showed 14 compounds. The main compounds were piperitone (45.72%), D-limonene (9.67%), and piperitenone (5.89%). The essential oil was active against larvae of Ae. aegypti, with LC50 of 79.78 microg/ml and LC90 of 100.84 microg/ml. The larvicidal thiophene contents were higher in the roots and flowers as demonstrated by high-performance liquid chromatography analysis. Thus, T. erecta constitutes a good source of varied compounds showing larvicidal activity against Ae. aegypti. PMID:21805850

  10. The complete mitochondrial DNA genome of Aedes vigilax (Diptera: Culicidae).

    PubMed

    Hardy, C M; Court, L N; Morgan, M J

    2016-07-01

    The complete mitochondrial genomes of two main clades of the medically significant saltmarsh mosquito Aedes vigilax Skuse (Diptera: Culicidae) were obtained using combined Illumina and Sanger sequencing. The two 15,877 bp circular genomes share 99.0% nucleotide identity and encode 37 genes with identical gene arrangement similar to previously published Culicidae species with a non-coding A + T rich region between rns and tRNA-Ile. Protein initiation codon is ATN apart from ND5 (GTG) and COX1 (TCG). Eight protein-coding genes encode full TAA stop codon, while five are completed by mRNA polyadenylation. Typical cloverleaf structures containing DHU and TΨC stem and loops can be inferred for all 22 tRNAs. PMID:26099979

  11. The invasive mosquito Aedes japonicus in Central Europe.

    PubMed

    Schaffner, F; Kaufmann, C; Hegglin, D; Mathis, A

    2009-12-01

    Complaints about a biting pest led to the recognition of invasive Aedes (Finlaya) japonicus japonicus (Theobald) (Diptera: Culicidae) in Central Europe. Larval collections from cemetery vases revealed a colonized area of approximately 1400 km(2) in northern Switzerland spreading into bordering Germany, suggesting that the mosquito has been established in this region for several years. Within this range, larvae of Ae. japonicus were recovered from more containers than the most common resident culicid species Culex pipiens. Possible introduction sites (used tyre yards and international airports) revealed few or no larvae, and the mode of introduction remains unclear. Given the vector potential of this species for arboviruses, implementation of surveillance and control measures should be considered. PMID:19941611

  12. Repellents Inhibit P450 Enzymes in Stegomyia (Aedes) aegypti

    PubMed Central

    Jaramillo Ramirez, Gloria Isabel; Logan, James G.; Loza-Reyes, Elisa; Stashenko, Elena; Moores, Graham D.

    2012-01-01

    The primary defence against mosquitoes and other disease vectors is often the application of a repellent. Despite their common use, the mechanism(s) underlying the activity of repellents is not fully understood, with even the mode of action of DEET having been reported to be via different mechanisms; e.g. interference with olfactory receptor neurones or actively detected by olfactory receptor neurones on the antennae or maxillary palps. In this study, we discuss a novel mechanism for repellence, one of P450 inhibition. Thirteen essential oil extracts from Colombian plants were assayed for potency as P450 inhibitors, using a kinetic fluorometric assay, and for repellency using a modified World Health Organisation Pesticide Evaluations Scheme (WHOPES) arm-in cage assay with Stegomyia (Aedes) aegypti mosquitoes. Bootstrap analysis on the inhibition analysis revealed a significant correlation between P450-inhibition and repellent activity of the oils. PMID:23152795

  13. Temporal genetic stability of Stegomyia aegypti (= Aedes aegypti) populations.

    PubMed

    Gloria-Soria, A; Kellner, D A; Brown, J E; Gonzalez-Acosta, C; Kamgang, B; Lutwama, J; Powell, J R

    2016-06-01

    The mosquito Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) is the primary vector of viruses that cause yellow fever, dengue and Chikungunya fever. In the absence of effective vaccines, the reduction of these diseases relies on vector control strategies. The success of these strategies is tightly linked to the population dynamics of target populations. In the present study, 14 collections from St. aegypti populations separated by periods of 1-13 years were analysed to determine their temporal genetic stability. Although temporal structure is discernible in most populations, the degree of temporal differentiation is dependent on the population and does not obscure the geographic structure of the various populations. The results suggest that performing detailed studies in the years prior to and after population reduction- or modification-based control interventions at each target field site may be useful in assessing the probability of success. PMID:26744174

  14. Toxicities of certain larvicides to resistant and susceptible Aedes aegypti

    PubMed Central

    Klassen, W.; Keppler, W. J.; Kitzmiller, J. B.

    1965-01-01

    In a study of the toxicological characteristics of dieldrin-resistant and DDT-resistant strains of Aedes aegypti, combined with an evaluation of certain larvicides, 14 cyclodienes, 13 DDT-type compounds, 18 organophosphorus compounds, several carbamates and a number of other compounds were tested against larvae of A. aegypti. Telodrin and GC-9160 proved to be toxic against a highly dieldrin-resistant strain. Against highly DDT-resistant strains the toxicity of DDT could be enhanced by piperonyl butoxide, DMC or WARF, that of deutero-DDT by DMC, and that of methoxychlor by piperonyl butoxide. Prolan and Bulan were found to be slightly less effective than deutero-DDT against highly DDT-resistant strains. Among the more recent organophosphorus compounds found to exceed fenthion in toxicity are AC-52160, Stauffer N-2404, Folithion, Bayer 52957 and SD-7438. The effectiveness of dimethrin could be enhanced with piperonyl butoxide. PMID:5294255

  15. Invasion Biology of Aedes japonicus japonicus (Diptera: Culicidae)

    PubMed Central

    Fonseca, Dina M.

    2014-01-01

    Aedes japonicus japonicus (Theobald) (Diptera: Culicidae) has recently expanded beyond its native range of Japan and Korea into large parts of North America and Central Europe. Population genetic studies begun immediately after the species was detected in North America revealed genetically distinct introductions that subsequently merged, likely contributing to the successful expansion. Interactions, particularly in the larval stage, with other known disease vectors give this invasive subspecies the potential to influence local disease dynamics. Its successful invasion likely does not involve superior direct competitive abilities, but it is associated with the use of diverse larval habitats and a cold tolerance that allows an expanded seasonal activity range in temperate climates. We predict a continued but slower expansion of Ae. j. japonicus in North America and a continued rapid expansion into other areas as this mosquito will eventually be considered a permanent resident of much of North America, Europe, Asia, and parts of Hawaii. PMID:24397520

  16. Vitrified canine testicular cells allow the formation of spermatogonial stem cells and seminiferous tubules following their xenotransplantation into nude mice

    PubMed Central

    Lee, Kyung Hoon; Lee, Won Young; Kim, Dong Hoon; Lee, Seung Hoon; Do, Jung Tae; Park, Chankyu; Kim, Jae Hwan; Choi, Young Suk; Song, Hyuk

    2016-01-01

    Belgian Malinois (BM), one of the excellent military dog breeds in South Korea, is usually castrated before sexual maturation. Therefore, the transfer of their genetic features to the next generation is difficult. To overcome this, testicular cells from 4-month-old BMs were frozen. Testicular cells were thawed after 3 months and cultured in StemPro-34 medium. Spermatogonial stem cell (SSC) characteristics were determined by the transplantation of the cultured germ cell-derived colonies (GDCs) into empty testes, containing only several endogenous SSCs and Sertoli cells, of immunodeficient mice, 4 weeks after busulfan treatment. Following the implantation, the transplanted cells localized in the basement membrane of the seminiferous tubules, and ultimately colonized the recipient testes. Xenotransplantation of GDCs together with testicular somatic cells conjugated with extracellular matrix (ECM), led to the formation of de novo seminiferous tubules. These seminiferous tubules were mostly composed of Sertoli cells. Some germ cells were localized in the basement membrane of seminiferous tubules. This study revealed that BM-derived SSCs, obtained from the castrated testes, might be a valuable tool for the transfer of BM genetic features to the next generation. PMID:26907750

  17. A histological study of the effect of exogenous melatonin on gentamicin induced structural alterations of proximal tubules in rats

    PubMed Central

    Kapić, Dina; Mornjaković, Zakira; Ćosović, Esad; Šahinović, Maida

    2014-01-01

    The aim of this research was to assess the reactive changes of rat proximal tubules caused by gentamicin and the effect of relatively low doses of melatonin. 48 adult male Wistar rats were distributed into six groups of equal size which all received one of the following daily intraperitoneal injections: vehicle (5% ethanol in Ringer solution) during 11 days (C); gentamicin (80 mg/kg) during 8 days (G), two groups which concomitantly received gentamicin (80 mg/kg) during 8 days and melatonin in two different test doses (5 or 20 mg/kg) during 11 days (GM1, GM2) and two groups treated only with melatonin in two different doses (5 or 20 mg/kg) during 11 days (M1, M2). Histological analysis included qualitative and semi-quantitative light microscopy analysis of proximal tubules. Exogenous melatonin had no significant effect on the microstructure, independently of dosis. The changes of proximal tubules microstructure induced by gentamicin were expressed in the form of granulovacuolar degeneration, necrosis and desquamation. The grade of proximal tubular changes was smaller in animals who besides gentamicin received melatonin. Melatonin has a dose dependent protective effect on the structural alterations of proximal tubules of the kidney induced by gentamicin. PMID:24579968

  18. Identification of domains of the Tomato spotted wilt virus NSm protein involved in tubule formation, movement and symptomatology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deletion and alanine-substitution mutants of the Tomato spotted wilt virus NSm protein were generated to identify domains involved in tubule formation, movement and symptomatology, using a heterologous expression system derived from Tobacco mosaic virus. Two regions of NSm were required for both tub...

  19. Protein Kinase A Activity Is Necessary for Fission and Fusion of Golgi to Endoplasmic Reticulum Retrograde Tubules

    PubMed Central

    Tenorio, María J.; Luchsinger, Charlotte; Mardones, Gonzalo A.

    2015-01-01

    It is becoming increasingly accepted that together with vesicles, tubules play a major role in the transfer of cargo between different cellular compartments. In contrast to our understanding of the molecular mechanisms of vesicular transport, little is known about tubular transport. How signal transduction molecules regulate these two modes of membrane transport processes is also poorly understood. In this study we investigated whether protein kinase A (PKA) activity regulates the retrograde, tubular transport of Golgi matrix proteins from the Golgi to the endoplasmic reticulum (ER). We found that Golgi-to-ER retrograde transport of the Golgi matrix proteins giantin, GM130, GRASP55, GRASP65, and p115 was impaired in the presence of PKA inhibitors. In addition, we unexpectedly found accumulation of tubules containing both Golgi matrix proteins and resident Golgi transmembrane proteins. These tubules were still attached to the Golgi and were highly dynamic. Our data suggest that both fission and fusion of retrograde tubules are mechanisms regulated by PKA activity. PMID:26258546

  20. Automated Tubule Nuclei Quantification and Correlation with Oncotype DX risk categories in ER+ Breast Cancer Whole Slide Images.

    PubMed

    Romo-Bucheli, David; Janowczyk, Andrew; Gilmore, Hannah; Romero, Eduardo; Madabhushi, Anant

    2016-01-01

    Early stage estrogen receptor positive (ER+) breast cancer (BCa) treatment is based on the presumed aggressiveness and likelihood of cancer recurrence. Oncotype DX (ODX) and other gene expression tests have allowed for distinguishing the more aggressive ER+ BCa requiring adjuvant chemotherapy from the less aggressive cancers benefiting from hormonal therapy alone. However these tests are expensive, tissue destructive and require specialized facilities. Interestingly BCa grade has been shown to be correlated with the ODX risk score. Unfortunately Bloom-Richardson (BR) grade determined by pathologists can be variable. A constituent category in BR grading is tubule formation. This study aims to develop a deep learning classifier to automatically identify tubule nuclei from whole slide images (WSI) of ER+ BCa, the hypothesis being that the ratio of tubule nuclei to overall number of nuclei (a tubule formation indicator - TFI) correlates with the corresponding ODX risk categories. This correlation was assessed in 7513 fields extracted from 174 WSI. The results suggests that low ODX/BR cases have a larger TFI than high ODX/BR cases (p < 0.01). The low ODX/BR cases also presented a larger TFI than that obtained for the rest of cases (p < 0.05). Finally, the high ODX/BR cases have a significantly smaller TFI than that obtained for the rest of cases (p < 0.01). PMID:27599752

  1. The proximal tubule is the primary target of injury and progression of kidney disease: role of the glomerulotubular junction.

    PubMed

    Chevalier, Robert L

    2016-07-01

    There is an alarming global increase in the incidence of end-stage kidney disease, for which early biomarkers and effective treatment options are lacking. Largely based on the histology of the end-stage kidney and on the model of unilateral ureteral obstruction, current investigation is focused on the pathogenesis of renal interstitial fibrosis as a central mechanism in the progression of chronic kidney disease (CKD). It is now recognized that cumulative episodes of acute kidney injury (AKI) can lead to CKD, and, conversely, CKD is a risk factor for AKI. Based on recent and historic studies, this review shifts attention from the glomerulus and interstitium to the proximal tubule as the primary sensor and effector in the progression of CKD as well as AKI. Packed with mitochondria and dependent on oxidative phosphorylation, the proximal tubule is particularly vulnerable to injury (obstructive, ischemic, hypoxic, oxidative, metabolic), resulting in cell death and ultimately in the formation of atubular glomeruli. Animal models of human glomerular and tubular disorders have provided evidence for a broad repertoire of morphological and functional responses of the proximal tubule, revealing processes of degeneration and repair that may lead to new therapeutic strategies. Most promising are studies that encompass the entire life cycle from fetus to senescence, recognizing epigenetic factors. The application of techniques in molecular characterization of tubule segments and the development of human kidney organoids may provide new insights into the mammalian kidney subjected to stress or injury, leading to biomarkers of early CKD and new therapies. PMID:27194714

  2. Interaction of resident sperm with sperm-storage tubule (SST) epithelial cell microvilli in the turkey hen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Unlike most mammals, birds do not need to synchronize copulation with ovulation. Hens are endowed with tubular structures, the sperm-storage tubules (SST), in their oviducts which the sperm enter and survive for weeks after mating or artificial insemination. Sperm are slowly but continually releas...

  3. Vitrified canine testicular cells allow the formation of spermatogonial stem cells and seminiferous tubules following their xenotransplantation into nude mice.

    PubMed

    Lee, Kyung Hoon; Lee, Won Young; Kim, Dong Hoon; Lee, Seung Hoon; Do, Jung Tae; Park, Chankyu; Kim, Jae Hwan; Choi, Young Suk; Song, Hyuk

    2016-01-01

    Belgian Malinois (BM), one of the excellent military dog breeds in South Korea, is usually castrated before sexual maturation. Therefore, the transfer of their genetic features to the next generation is difficult. To overcome this, testicular cells from 4-month-old BMs were frozen. Testicular cells were thawed after 3 months and cultured in StemPro-34 medium. Spermatogonial stem cell (SSC) characteristics were determined by the transplantation of the cultured germ cell-derived colonies (GDCs) into empty testes, containing only several endogenous SSCs and Sertoli cells, of immunodeficient mice, 4 weeks after busulfan treatment. Following the implantation, the transplanted cells localized in the basement membrane of the seminiferous tubules, and ultimately colonized the recipient testes. Xenotransplantation of GDCs together with testicular somatic cells conjugated with extracellular matrix (ECM), led to the formation of de novo seminiferous tubules. These seminiferous tubules were mostly composed of Sertoli cells. Some germ cells were localized in the basement membrane of seminiferous tubules. This study revealed that BM-derived SSCs, obtained from the castrated testes, might be a valuable tool for the transfer of BM genetic features to the next generation. PMID:26907750

  4. Automated Tubule Nuclei Quantification and Correlation with Oncotype DX risk categories in ER+ Breast Cancer Whole Slide Images

    PubMed Central

    Romo-Bucheli, David; Janowczyk, Andrew; Gilmore, Hannah; Romero, Eduardo; Madabhushi, Anant

    2016-01-01

    Early stage estrogen receptor positive (ER+) breast cancer (BCa) treatment is based on the presumed aggressiveness and likelihood of cancer recurrence. Oncotype DX (ODX) and other gene expression tests have allowed for distinguishing the more aggressive ER+ BCa requiring adjuvant chemotherapy from the less aggressive cancers benefiting from hormonal therapy alone. However these tests are expensive, tissue destructive and require specialized facilities. Interestingly BCa grade has been shown to be correlated with the ODX risk score. Unfortunately Bloom-Richardson (BR) grade determined by pathologists can be variable. A constituent category in BR grading is tubule formation. This study aims to develop a deep learning classifier to automatically identify tubule nuclei from whole slide images (WSI) of ER+ BCa, the hypothesis being that the ratio of tubule nuclei to overall number of nuclei (a tubule formation indicator - TFI) correlates with the corresponding ODX risk categories. This correlation was assessed in 7513 fields extracted from 174 WSI. The results suggests that low ODX/BR cases have a larger TFI than high ODX/BR cases (p < 0.01). The low ODX/BR cases also presented a larger TFI than that obtained for the rest of cases (p < 0.05). Finally, the high ODX/BR cases have a significantly smaller TFI than that obtained for the rest of cases (p < 0.01). PMID:27599752

  5. Differentiation of human umbilical cord mesenchymal stem cells into germ-like cells in mouse seminiferous tubules

    PubMed Central

    CHEN, HUI; TANG, QIU-LING; WU, XIAO-YING; XIE, LI-CHUN; LIN, LI-MIN; HO, GU-YU; MA, LIAN

    2015-01-01

    Our previous study demonstrated that human umbilical cord mesenchymal stem cells (HUMSCs) were capable of differentiation into germ cells in vitro. To assess this potential in vivo, HUMSCs were microinjected into the lumen of seminiferous tubules of immunocompetent mice, which were treated with busulfan to destroy endogenous spermatogenesis. Bromodeoxyuridine labeling studies demonstrated that HUMSCs survived in the tubule for at least 120 days, exhibited a round cell shape typical of proliferating or differentiating germ cells, migrated to the basement of the tubule, where proliferating spermatogonia reside and returned to the luminal compartment, where differentiating spermatids and spermatozoa reside. The migration pattern resembled that of germ cell development in vivo. Immunohistochemical and colocalization studies revealed that transplanted HUMSCs expressed the germ cell markers octamer-binding transcription factor 4, α6 integrin, C-kit and VASA, confirming the germ cell differentiation. In addition, it was observed that tubules transplanted with HUMSCs exhibited marked improvement in the histological features damaged by the chemotherapeutic busulfan, as judged by morphology and quantitative histology. Taken together, these data demonstrated the capacity of HUMSCs to form germ cells in the testes and to repair testicular tissue. These findings suggest a potential utility of HUMSCs to treat the infertility and testicular insufficiency caused by cancer therapeutics. PMID:25815600

  6. Interaction of resident sperm with sperm-storage tubule (SST) epithelial cell microvilli in the turkey breeder hen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interaction of resident sperm with sperm-storage tubule (SST) epithelial cell microvilli in the turkey breeder hen M.R. Bakst*1 and C. Murphy2, 1Animal Biosciences and Biotechnology Laboratory, 2Electron & Confocal Microscopy Unit, Beltsville Area, ARS, USDA, Beltsville MD Sustained fertilization o...

  7. Effect of triflumuron, a chitin synthesis inhibitor, on Aedes aegypti, Aedes albopictus and Culex quinquefasciatus under laboratory conditions

    PubMed Central

    2013-01-01

    Background Resistance to traditional insecticides represents a threat to the control of disease vectors. The insect growth regulators (IGR) are a potential alternative to control mosquitoes, including resistant populations. The chitin synthesis inhibitors (CSI) are IGRs, which interfere with the insect molting process and represent one major class of compounds against Aedes aegypti populations resistant to the larvicide organophosphate temephos. In the present study, we evaluated the efficacy of the CSI triflumuron on Culex quinquefasciatus, Aedes albopictus and against several Ae. aegypti field populations. Methods The efficacy of triflumuron, against Cx. quinquefasciatus and Ae. albopictus was evaluated with laboratory strains through dose–response assays. Additionaly, this CSI was tested against seven Ae. aegypti field populations exhibiting distinct resistance levels to both temephos and the pyrethroid deltamethrin. Aedes aegypti populations were exposed to both a dose that inhibits 99% of the adult emergence of mosquitoes from the susceptible reference strain, Rockefeller, (EI99 = 3.95 μg/L) and the diagnostic dose (DD), corresponding to twice the EI99. Results Our results indicate that triflumuron was effective in emergence inhibition (EI) of Cx. quinquefasciatus (EI50= 5.28 μg/L; EI90= 12.47 μg/L) and Ae. albopictus (EI50= 1.59 μg/L; EI90= 2.63 μg/L). Triflumuron was also effective against seven Ae. aegypti Brazilian populations resistant to both temephos and deltamethrin. Exposure of all the Ae. aegypti populations to the triflumuron EI99 of the susceptible reference strain, Rockefeller, resulted in complete inhibition of adult emergence, suggesting no cross-resistance among traditional insecticides and this CSI. However, a positive correlation between temephos resistance and tolerance to triflumuron was observed. Conclusion The results suggest that triflumuron represents a potential tool for the control of disease vectors in public

  8. Interpopulation divergence in competitive interactions of the mosquito Aedes albopictus

    PubMed Central

    Leisnham, P. T.; Lounibos, L.P.; O’Meara, G.F.; Juliano, S.A.

    2009-01-01

    Geographic variation in species interactions can have major effects on distributions. Effects of such variation can be particularly evident for invasive species, in which variation in competitive ability can influence invasive success and impacts. We tested the hypothesis that coexistence or exclusion of the resident mosquito Aedes aegypti results from variation among local populations of the invasive Aedes albopictus in competitive interactions with A. aegypti. We also examined the role of variation in fecundity-size relationship in these competitive interactions. We compared competitive abilities of nine North American populations of A. albopictus, three populations from each of three site types: extinction of A. aegypti following A. albopictus invasion, coexistence following A. albopictus invasion, and A. albopictus allopatric to A. aegypti. Competition among larvae from each A. albopictus population and a single A. aegypti population was tested in laboratory microcosms in a response-surface design. We found interpopulation differences in competitive ability of A. albopictus, but no strong patterns among site types. Extinction sites had steeper average fecundity-size relationships than coexistence sites and allopatric sites, but this did not translate into superior population performance. Certain individual A. albopictus populations had exceptionally large competitive effects on A. aegypti or poor competitive responses to competition from A. aegypti, but competitive effect and response were not correlated. These results suggest that interpopulation variation in the competitive ability of A. albopictus may only partly explain geographic pattern of coexistence with or extinction of A. aegypti. Environmental differences among regions may affect the competitive ability of A. albopictus and influence its invasion success and impact. PMID:19769119

  9. Cumulative mortality of Aedes aegypti larvae treated with compounds.

    PubMed

    Torres, Sandra Maria; Cruz, Nadine Louise Nicolau da; Rolim, Vitor Pereira de Matos; Cavalcanti, Maria Inês de Assis; Alves, Leucio Câmara; Silva Júnior, Valdemiro Amaro da

    2014-06-01

    OBJECTIVE To evaluate the larvicidal activity of Azadirachta indica, Melaleuca alternifolia, carapa guianensis essential oils and fermented extract of Carica papaya against Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae). METHODS The larvicide test was performed in triplicate with 300 larvae for each experimental group using the third larval stage, which were exposed for 24h. The groups were: positive control with industrial larvicide (BTI) in concentrations of 0.37 ppm (PC1) and 0.06 ppm (PC2); treated with compounds of essential oils and fermented extract, 50.0% concentration (G1); treated with compounds of essential oils and fermented extract, 25.0% concentration (G2); treated with compounds of essential oils and fermented extract, 12.5% concentration (G3); and negative control group using water (NC1) and using dimethyl (NC2). The larvae were monitored every 60 min using direct visualization. RESULTS No mortality occurred in experimental groups NC1 and NC2 in the 24h exposure period, whereas there was 100% mortality in the PC1 and PC2 groups compared to NC1 and NC2. Mortality rates of 65.0%, 50.0% and 78.0% were observed in the groups G1, G2 and G3 respectively, compared with NC1 and NC2. CONCLUSIONS The association between three essential oils from Azadirachta indica, Melaleuca alternifolia, Carapa guianensis and fermented extract of Carica papaya was efficient at all concentrations. Therefore, it can be used in Aedes aegypti Liverpool third larvae stage control programs. PMID:25119939

  10. Cumulative mortality of Aedes aegypti larvae treated with compounds

    PubMed Central

    Torres, Sandra Maria; da Cruz, Nadine Louise Nicolau; Rolim, Vitor Pereira de Matos; Cavalcanti, Maria Inês de Assis; Alves, Leucio Câmara; da Silva, Valdemiro Amaro

    2014-01-01

    OBJECTIVE To evaluate the larvicidal activity of Azadirachta indica, Melaleuca alternifolia, carapa guianensis essential oils and fermented extract of Carica papaya against Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae). METHODS The larvicide test was performed in triplicate with 300 larvae for each experimental group using the third larval stage, which were exposed for 24h. The groups were: positive control with industrial larvicide (BTI) in concentrations of 0.37 ppm (PC1) and 0.06 ppm (PC2); treated with compounds of essential oils and fermented extract, 50.0% concentration (G1); treated with compounds of essential oils and fermented extract, 25.0% concentration (G2); treated with compounds of essential oils and fermented extract, 12.5% concentration (G3); and negative control group using water (NC1) and using dimethyl (NC2). The larvae were monitored every 60 min using direct visualization. RESULTS No mortality occurred in experimental groups NC1 and NC2 in the 24h exposure period, whereas there was 100% mortality in the PC1 and PC2 groups compared to NC1 and NC2. Mortality rates of 65.0%, 50.0% and 78.0% were observed in the groups G1, G2 and G3 respectively, compared with NC1 and NC2. CONCLUSIONS The association between three essential oils from Azadirachta indica, Melaleuca alternifolia, Carapa guianensis and fermented extract of Carica papaya was efficient at all concentrations. Therefore, it can be used in Aedes aegypti Liverpool third larvae stage control programs. PMID:25119939

  11. Wolbachia Modulates Lipid Metabolism in Aedes albopictus Mosquito Cells

    PubMed Central

    Molloy, Jennifer C.; Sommer, Ulf; Viant, Mark R.

    2016-01-01

    ABSTRACT Certain strains of the intracellular endosymbiont Wolbachia can strongly inhibit or block the transmission of viruses such as dengue virus (DENV) by Aedes mosquitoes, and the mechanisms responsible are still not well understood. Direct infusion and liquid chromatography-Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry-based lipidomics analyses were conducted using Aedes albopictus Aa23 cells that were infected with the wMel and wMelPop strains of Wolbachia in comparison to uninfected Aa23-T cells. Substantial shifts in the cellular lipid profile were apparent in the presence of Wolbachia. Most significantly, almost all sphingolipid classes were depleted, and some reductions in diacylglycerols and phosphatidylcholines were also observed. These lipid classes have previously been shown to be selectively enriched in DENV-infected mosquito cells, suggesting that Wolbachia may produce a cellular lipid environment that is antagonistic to viral replication. The data improve our understanding of the intracellular interactions between Wolbachia and mosquitoes. IMPORTANCE Mosquitoes transmit a variety of important viruses to humans, such as dengue virus and Zika virus. Certain strains of the intracellular bacterial genus called Wolbachia found in or introduced into mosquitoes can block the transmission of viruses, including dengue virus, but the mechanisms responsible are not well understood. We found substantial shifts in the cellular lipid profiles in the presence of these bacteria. Some lipid classes previously shown to be enriched in dengue virus-infected mosquito cells were depleted in the presence of Wolbachia, suggesting that Wolbachia may produce a cellular lipid environment that inhibits mosquito-borne viruses. PMID:26994075

  12. Early enhancement of fluid transport in rabbit proximal straight tubules after loss of contralateral renal excretory function.

    PubMed Central

    Tabei, K; Levenson, D J; Brenner, B M

    1983-01-01

    To assess the renal functional adaptation to reduced excretory capacity, we studied whole kidney and single nephron function in anesthetized volume-replete rabbits after unilateral (left kidney) nephrectomy (UNX), ureteral obstruction (UO), or ureteroperitoneostomy (UP). At 24 h, despite the absence of measurable hypertrophy of the contralateral (right) kidney, these procedures significantly increased p-aminohippurate clearance (45-54%) and inulin clearance (CIN) (64-110%) compared with sham-operated control animals. In each group, whole kidney sodium reabsorption increased in proportion to the rise in CIN. To determine whether the intrinsic transport capacity of proximal tubule segments is altered by these maneuvers, we measured fluid volume reabsorption rate (Jv) in isolated superficial proximal straight tubule (PST) segments perfused in vitro, comparing each control tubule (obtained by biopsy of the left kidney immediately before an experimental maneuver) with a corresponding tubule segment obtained 24 h or 7 d later from the contralateral kidney. Control tubule Jv in sham-24 h animals averaged 0.48 +/- 0.04 nl/(min X mm). Jv did not change significantly at 24 h or 7 d after sham maneuvers but increased significantly at 24 h after UNX [delta Jv = 0.13 +/- 0.03 nl/(min X mm)], UO [delta Jv = 0.10 +/- 0.04 nl/(min X mm)], and UP [delta Jv = 0.13 +/- 0.04 nl/(min X mm)]. Jv remained increased by similar amounts at 7 d after UNX and UO. To evaluate whether an increase in glomerular filtration rate (GFR) might be the stimulus to this augmentation in Jv values, methylprednisolone (MP) (15 mg/kg per d) was administered daily to sham-operated animals, a maneuver which induced a 73% rise in CIN by day 5. This procedure also produced a significant increase in Jv in PST at 5 d [delta Jv = 0.16 +/- 0.05 nl/(min X mm)]. The increase in Jv evident in each group at 5 or 7 d was paralleled by an equivalent change in tubule cell volume and apparent tubule luminal surface area in

  13. Gluconeogenesis from glutamine and lactate in the isolated human renal proximal tubule: longitudinal heterogeneity and lack of response to adrenaline.

    PubMed Central

    Conjard, A; Martin, M; Guitton, J; Baverel, G; Ferrier, B

    2001-01-01

    Recent studies in vivo have suggested that, in humans in the postabsorptive state, the kidneys contribute a significant fraction of systemic gluconeogenesis, and that the stimulation of renal gluconeogenesis may fully explain the increase in systemic gluconeogenesis during adrenaline infusion. Given the potential importance of human renal gluconeogenesis in various physiological and pathophysiological situations, we have conducted a study in vitro to further characterize this metabolic process and its regulation. For this, successive segments (S1, S2 and S3) of human proximal tubules were dissected and incubated with physiological concentrations of glutamine or lactate, two potential gluconeogenic substrates that are taken up by the human kidney in vivo, and glucose production was measured. The effects of adrenaline, noradrenaline and cAMP, a well established stimulator of gluconeogenesis in animal kidney tubules, were also studied in suspensions of human renal proximal tubules. The results indicate that the three successive segments have about the same capacity to synthesize glucose from glutamine; by contrast, the S2 and S3 segments synthesize more glucose from lactate than the S1 segment. In the S2 and S3 segments, lactate appears to be a better gluconeogenic precursor than glutamine. The addition of cAMP, but not of adrenaline or noradrenaline, led to the stimulation of gluconeogenesis from lactate and glutamine by human proximal tubules. These results indicate that, in the human kidney in vivo, lactate might be the main gluconeogenic precursor, and that the stimulation of renal gluconeogenesis observed in vivo upon adrenaline infusion may result from an indirect action on the renal proximal tubule. PMID:11716765

  14. Tubular proteinuria in patients with HNF1α mutations: HNF1α drives endocytosis in the proximal tubule.

    PubMed

    Terryn, Sara; Tanaka, Karo; Lengelé, Jean-Philippe; Olinger, Eric; Dubois-Laforgue, Danièle; Garbay, Serge; Kozyraki, Renata; Van Der Smissen, Patrick; Christensen, Erik I; Courtoy, Pierre J; Bellanné-Chantelot, Christine; Timsit, José; Pontoglio, Marco; Devuyst, Olivier

    2016-05-01

    Hepatocyte nuclear factor 1α (HNF1α) is a transcription factor expressed in the liver, pancreas, and proximal tubule of the kidney. Mutations of HNF1α cause an autosomal dominant form of diabetes mellitus (MODY-HNF1A) and tubular dysfunction. To gain insights into the role of HNF1α in the proximal tubule, we analyzed Hnf1a-deficient mice. Compared with wild-type littermates, Hnf1a knockout mice showed low-molecular-weight proteinuria and a 70% decrease in the uptake of β2-microglobulin, indicating a major endocytic defect due to decreased expression of megalin/cubilin receptors. We identified several binding sites for HNF1α in promoters of Lrp2 and Cubn genes encoding megalin and cubilin, respectively. The functional interaction of HNF1α with these promoters was shown in C33 epithelial cells lacking endogenous HNF1α. Defective receptor-mediated endocytosis was confirmed in proximal tubule cells from these knockout mice and could be rescued by transfection of wild-type but not mutant HNF1α. Transfection of human proximal tubule HK2 cells with HNF1α was able to upregulate megalin and cubilin expression and to increase endocytosis of albumin. Low-molecular-weight proteinuria was consistently detected in individuals with HNF1A mutations compared with healthy controls and patients with non-MODY-HNF1A diabetes mellitus. Thus, HNF1α plays a key role in the constitutive expression of megalin and cubilin, hence regulating endocytosis in the proximal tubule of the kidney. These findings provide new insight into the renal phenotype of individuals with mutations of HNF1A. PMID:27083284

  15. Drosophila Nedd4-long reduces Amphiphysin levels in muscles and leads to impaired T-tubule formation

    PubMed Central

    Safi, Frozan; Shteiman-Kotler, Alina; Zhong, Yunan; Iliadi, Konstantin G.; Boulianne, Gabrielle L.; Rotin, Daniela

    2016-01-01

    Drosophila Nedd4 (dNedd4) is a HECT ubiquitin ligase with two main splice isoforms: dNedd4-short (dNedd4S) and -long (dNedd4Lo). DNedd4Lo has a unique N-terminus containing a Pro-rich region. We previously showed that whereas dNedd4S promotes neuromuscular synaptogenesis, dNedd4Lo inhibits it and impairs larval locomotion. To delineate the cause of the impaired locomotion, we searched for binding partners to the N-terminal unique region of dNedd4Lo in larval lysates using mass spectrometry and identified Amphiphysin (dAmph). dAmph is a postsynaptic protein containing SH3-BAR domains and regulates muscle transverse tubule (T-tubule) formation in flies. We validated the interaction by coimmunoprecipitation and showed direct binding between dAmph-SH3 domain and dNedd4Lo N-terminus. Accordingly, dNedd4Lo was colocalized with dAmph postsynaptically and at muscle T-tubules. Moreover, expression of dNedd4Lo in muscle during embryonic development led to disappearance of dAmph and impaired T-tubule formation, phenocopying amph-null mutants. This effect was not seen in muscles expressing dNedd4S or a catalytically-inactive dNedd4Lo(C→A). We propose that dNedd4Lo destabilizes dAmph in muscles, leading to impaired T-tubule formation and muscle function. PMID:26823013

  16. The Efficacy of Some Commercially Available Insect Repellents for Aedes aegypti (Diptera: Culicidae) and Aedes albopictus (Diptera: Culicidae).

    PubMed

    Rodriguez, Stacy D; Drake, Lisa L; Price, David P; Hammond, John I; Hansen, Immo A

    2015-01-01

    Reducing the number of host-vector interactions is an effective way to reduce the spread of vector-borne diseases. Repellents are widely used to protect humans from a variety of protozoans, viruses, and nematodes. DEET (N,N-Diethyl-meta-toluamide), a safe and effective repellent, was developed during World War II. Fear of possible side effects of DEET has created a large market for "natural" DEET-free repellents with a variety of active ingredients. We present a comparative study on the efficacy of eight commercially available products, two fragrances, and a vitamin B patch. The products were tested using a human hand as attractant in a Y-tube olfactometer setup with Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse), both major human disease vectors. We found that Ae. albopictus were generally less attracted to the test subject's hand compared with Ae, aegypti. Repellents with DEET as active ingredient had a prominent repellency effect over longer times and on both species. Repellents containing p-menthane-3,8-diol produced comparable results but for shorter time periods. Some of the DEET-free products containing citronella or geraniol did not have any significant repellency effect. Interestingly, the perfume we tested had a modest repellency effect early after application, and the vitamin B patch had no effect on either species. This study shows that the different active ingredients in commercially available mosquito repellent products are not equivalent in terms of duration and strength of repellency. Our results suggest that products containing DEET or p-menthane-3,8-diol have long-lasting repellent effects and therefore provide good protection from mosquito-borne diseases. PMID:26443777

  17. The Efficacy of Some Commercially Available Insect Repellents for Aedes aegypti (Diptera: Culicidae) and Aedes albopictus (Diptera: Culicidae)

    PubMed Central

    Rodriguez, Stacy D.; Drake, Lisa L.; Price, David P.; Hammond, John I.; Hansen, Immo A.

    2015-01-01

    Reducing the number of host-vector interactions is an effective way to reduce the spread of vector-borne diseases. Repellents are widely used to protect humans from a variety of protozoans, viruses, and nematodes. DEET (N,N-Diethyl-meta-toluamide), a safe and effective repellent, was developed during World War II. Fear of possible side effects of DEET has created a large market for “natural” DEET-free repellents with a variety of active ingredients. We present a comparative study on the efficacy of eight commercially available products, two fragrances, and a vitamin B patch. The products were tested using a human hand as attractant in a Y-tube olfactometer setup with Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse), both major human disease vectors. We found that Ae. albopictus were generally less attracted to the test subject’s hand compared with Ae, aegypti. Repellents with DEET as active ingredient had a prominent repellency effect over longer times and on both species. Repellents containing p-menthane-3,8-diol produced comparable results but for shorter time periods. Some of the DEET-free products containing citronella or geraniol did not have any significant repellency effect. Interestingly, the perfume we tested had a modest repellency effect early after application, and the vitamin B patch had no effect on either species. This study shows that the different active ingredients in commercially available mosquito repellent products are not equivalent in terms of duration and strength of repellency. Our results suggest that products containing DEET or p-menthane-3,8-diol have long-lasting repellent effects and therefore provide good protection from mosquito-borne diseases. PMID:26443777

  18. Prostaglandin E2 increases proximal tubule fluid reabsorption, and modulates cultured proximal tubule cell responses via EP1 and EP4 receptors.

    PubMed

    Nasrallah, Rania; Hassouneh, Ramzi; Zimpelmann, Joseph; Karam, Andrew J; Thibodeau, Jean-Francois; Burger, Dylan; Burns, Kevin D; Kennedy, Chris Rj; Hébert, Richard L

    2015-09-01

    Renal prostaglandin (PG) E2 regulates salt and water transport, and affects disease processes via EP1-4 receptors, but its role in the proximal tubule (PT) is unknown. Our study investigates the effects of PGE2 on mouse PT fluid reabsorption, and its role in growth, sodium transporter expression, fibrosis, and oxidative stress in a mouse PT cell line (MCT). To determine which PGE2 EP receptors are expressed in MCT, qPCR for EP1-4 was performed on cells stimulated for 24 h with PGE2 or transforming growth factor beta (TGFβ), a known mediator of PT injury in kidney disease. EP1 and EP4 were detected in MCT, but EP2 and EP3 are not expressed. EP1 was increased by PGE2 and TGFβ, but EP4 was unchanged. To confirm the involvement of EP1 and EP4, sulprostone (SLP, EP1/3 agonist), ONO8711 (EP1 antagonist), and EP1 and EP4 siRNA were used. We first show that PGE2, SLP, and TGFβ reduced H(3)-thymidine and H(3)-leucine incorporation. The effects on cell-cycle regulators were examined by western blot. PGE2 increased p27 via EP1 and EP4, but TGFβ increased p21; PGE2-induced p27 was attenuated by TGFβ. PGE2 and SLP reduced cyclinE, while TGFβ increased cyclinD1, an effect attenuated by PGE2 administration. Na-K-ATPase α1 (NaK) was increased by PGE2 via EP1 and EP4. TGFβ had no effect on NaK. Additionally, PGE2 and TGFβ increased fibronectin levels, reaching 12-fold upon co-stimulation. EP1 siRNA abrogated PGE2-fibronectin. PGE2 also increased ROS generation, and ONO-8711 blocked PGE2-ROS. Finally, PGE2 significantly increased fluid reabsorption by 31 and 46% in isolated perfused mouse PT from C57BL/6 and FVB mice, respectively, and this was attenuated in FVB-EP1 null mice. Altogether PGE2 acting on EP1 and EP4 receptors may prove to be important mediators of PT injury, and salt and water transport. PMID:26121313

  19. Vector competence of Aedes aegypti and Aedes vittatus (Diptera: Culicidae) from Senegal and Cape Verde archipelago for West African lineages of chikungunya virus.

    PubMed

    Diagne, Cheikh T; Faye, Oumar; Guerbois, Mathilde; Knight, Rachel; Diallo, Diawo; Faye, Ousmane; Ba, Yamar; Dia, Ibrahima; Faye, Ousmane; Weaver, Scott C; Sall, Amadou A; Diallo, Mawlouth

    2014-09-01

    To assess the risk of emergence of chikungunya virus (CHIKV) in West Africa, vector competence of wild-type, urban, and non-urban Aedes aegypti and Ae. vittatus from Senegal and Cape Verde for CHIKV was investigated. Mosquitoes were fed orally with CHIKV isolates from mosquitoes (ArD30237), bats (CS13-288), and humans (HD180738). After 5, 10, and 15 days of incubation following an infectious blood meal, presence of CHIKV RNA was determined in bodies, legs/wings, and saliva using real-time reverse transcription-polymerase chain reaction. Aedes vittatus showed high susceptibility (50-100%) and early dissemination and transmission of all CHIKV strains tested. Aedes aegypti exhibited infection rates ranging from 0% to 50%. Aedes aegypti from Cape Verde and Kedougou, but not those from Dakar, showed the potential to transmit CHIKV in saliva. Analysis of biology and competence showed relatively high infective survival rates for Ae. vittatus and Ae. aegypti from Cape Verde, suggesting their efficient vector capacity in West Africa. PMID:25002293

  20. The effect of Piper aduncum Linn. (Family: Piperaceae) essential oil as aerosol spray against Aedes aegypti (L.) and Aedes albopictus Skuse.

    PubMed

    Misni, Norashiqin; Othman, Hidayatulfathi; Sulaiman, Sallehudin

    2011-08-01

    The bioefficacy of Piper aduncum L. essential oil formulated in aerosol cans was evaluated against Aedes aegypti and Aedes albopictus in a simulated room. The aerosol spray test was based on the Malaysian test standard for aerosol (MS 1221:1991UDC 632.982.2 modified from WHO 2009 methodology) and examined the knockdown effect within 20 minutes of exposure. Mortality rate after 24 hour of holding period was also determined. A commercial aerosol spray (0.09% prallethrin 0.05% d-phenothrin) was also tested as a comparison. Our results showed that the knockdown effect of the commercial aerosol spray and P. aduncum essential oil spray (8% and 10% concentrations) was significantly higher in Ae. albopictus adult females, when compared with that of Ae. aegypti adult females (P<0.05). There was a significant difference in knockdown between commercial aerosol spray and essential oil spray for both Aedes spp. (P<0.05). The essential oil induced significantly higher mortality in Ae. aegypti (80%) than in Ae. albopictus (71.6%) (P<0.05). The commercial aerosol spray caused 97.7% and 86.5% mortality against Ae. aegypti and Ae. albopictus respectively (P<0.05). Based on these data, P. aduncum essential oil has the potential to be used as an aerosol spray against Aedes spp. PMID:22041743

  1. Influence of Ultrasonic Irrigation and Chloroform on Cleanliness of Dentinal Tubules During Endodontic Retreatment-An Invitro SEM Study

    PubMed Central

    Singhal, Anurag; Gurtu, Anuraag; Vinayak, Vineet

    2015-01-01

    Background Ultrasonic irrigation has been proved for its remarkable cleaning efficiency in the field of endodontics. But its role in endodontic re-treatment has been understated. There is not much data available to understand the effect of ultrasonic irrigation for the evaluation of cleanliness of dentinal tubules when it is used with or without chloroform, a gutta percha solvent during endodontic retreatment. Aim To compare the influence of ultrasonic irrigation with syringe irrigation on cleanliness of dentinal tubules after gutta perch removal for endodontic retreatment with or without the use of chloroform a gutta percha solvent using scanning electron microscope (SEM). Materials and Methods Freshly extracted 45 human mandibular premolar teeth for periodontal and orthodontic reasons were taken and were occlusally adjusted to a working length of 19 mm. The root canals of all teeth were prepared chemo mechanically to a master apical file size 40 and were divided in various groups. In Group 1 (n = 5; control group), the canals remained unfilled. In Groups 2 and 3 (n = 20 each), the canals were filled using lateral compaction with gutta-percha and AH plus sealer, removal of root fillings was undertaken after 2 weeks using Gates Glidden drills and H files without chloroform in Group 2 and with chloroform in group 3. The specimen of Group 2 and 3 were further divided into two subgroups I and II (n=10). In subgroup I, irrigation was done using side vented needles and sodium hypochlorite. In subgroup II irrigation was done using passive ultrasonic irrigation with sodium hypochlorite. Thereafter, the roots were split and the sections were observed under SEM. The number of occluded dentinal tubules /total number of dentinal tubules were calculated for the coronal, middle and apical third of each root half. Statistical analysis was performed using one-way ANOVA followed by Tukey’s test using standardized technique. Result Results indicated that the cleanest dentinal

  2. The structure of the chorion and associated surface filaments in Oryzias--evidence for the presence of extracellular tubules.

    PubMed

    Hart, N H; Pietri, R; Donovan, M

    1984-05-01

    The structure of the chorion with its associated surface filaments has been examined in Oryzias latipes using several techniques, including scanning and transmission electron microscopy, enzymatic digestion, and sodium dodecylsulfate-polyacrylamide gel electrophoresis. The chorion of the recently fertilized egg was found to be organized into three zones: an outer, fuzzy electron-lucent zone that was continuous over the surface of filaments, a middle, homogeneous electron-dense zone, and an inner zone of ten to 12 horizontal, fibrous lamellae. Two topographically distinct types of filaments were found on the chorionic surface: nonattaching and attaching. Nonattaching filaments showed a regular spatial distribution over the chorion with an interfilament distance of about 60-70 microns. Attaching filaments originated from a localized portion of the chorion and united with those of neighboring eggs to anchor the egg cluster to the gonoduct of the female. Both nonattaching and attaching filaments were morphologically regionalized into basal and distal segments. Internally, nonattaching and attaching filaments were constructed of unbranched, packed tubules with an average outside diameter of approximately 19.5 and 18.8 nm, respectively. Using the attaching filament for further study, it was determined by rotational analysis (Markham et al., '63) that the wall of each tubule was a cylinder composed of 14 globular subunits. Two structural types of attaching filaments were identified. The type I attaching filament was similar in internal organization to the nonattaching filament and consisted of only tubules. The type II attaching filament, however, showed a highly osmiophilic, electron-dense bar surrounded by packed tubules. Tubules of attaching filaments of the adult were resistant to the action of Triton X-100 and colchicine, but sensitive to a 0.1% protease solution. However, colchicine-treated ovary tissue showed an absence and pattern of disorganization of tubules at

  3. Efficacy of ovitrap colors and patterns for attracting Aedes albopictus at suburban field sites in North-Central Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We sought to visually enhance the attractiveness of a standard black ovitrap routinely used in surveillance of the Asian Tiger Mosquito, Aedes albopictus, and now being used as lethal ovitraps in Aedes aegypti dengue control programs. Black plastic drinking cups (ovitraps) were visually altered to ...

  4. Aldosterone sensitizes connecting tubule glomerular feedback via the aldosterone receptor GPR30

    PubMed Central

    Ren, YiLin; D'Ambrosio, Martin A.; Garvin, Jeffrey L.; Leung, Pablo; Kutskill, Kristopher; Wang, Hong; Peterson, Edward L.

    2014-01-01

    Increasing Na delivery to epithelial Na channels (ENaC) in the connecting tubule (CNT) dilates the afferent arteriole (Af-Art), a process we call connecting tubule glomerular feedback (CTGF). We hypothesize that aldosterone sensitizes CTGF via a nongenomic mechanism that stimulates CNT ENaC via the aldosterone receptor GPR30. Rabbit Af-Arts and their adherent CNTs were microdissected and simultaneously perfused. Two consecutive CTGF curves were elicited by increasing luminal NaCl in the CNT. During the control period, the concentration of NaCl that elicited a half-maximal response (EC50) was 37.0 ± 2.0 mmol/l; addition of aldosterone 10−8 mol/l to the CNT lumen caused a left-shift (decrease) in EC50 to 19.3 ± 1.3 mmol/l (P = 0.001 vs. control; n = 6). Neither the transcription inhibitor actinomycin D nor the translation inhibitor cycloheximide prevented the effect of aldosterone (control EC50 = 34.7 ± 1.9 mmol/l; aldosterone+actinomycin D EC50 = 22.6 ± 1.6 mmol/l; P < 0.001 and control EC50 = 32.4 ± 4.3 mmol/l; aldosterone+cycloheximide EC50 = 17.4 ± 3.3 mmol/l; P < 0.001). The aldosterone antagonist eplerenone prevented the sensitization of CTGF by aldosterone (control EC50 = 33.2 ± 1.7 mmol/l; aldosterone+eplerenone EC50 = 33.5 ± 1.3 mmol/l; n = 7). The GPR30 receptor blocker G-36 blocked the sensitization of CTGF by aldosterone (aldosterone EC50 = 16.5 ± 1.9 mmol/l; aldosterone+G-36 EC50 = 29.0 ± 2.1 mmol/l; n = 7; P < 0.001). Finally, we found that the sensitization of CTGF by aldosterone was mediated, at least in part, by the sodium/hydrogen exchanger (NHE). We conclude that aldosterone in the CNT lumen sensitizes CTGF via a nongenomic effect involving GPR30 receptors and NHE. Sensitized CTGF induced by aldosterone may contribute to renal damage by increasing Af-Art dilation and glomerular capillary pressure (glomerular barotrauma). PMID:24966088

  5. A bradykinin-potentiating peptide (BPP-10c) from Bothrops jararaca induces changes in seminiferous tubules

    PubMed Central

    2013-01-01

    Background The testis-specific isoform of angiotensin-converting enzyme (tACE) is exclusively expressed in germ cells during spermatogenesis. Although the exact role of tACE in male fertility is unknown, it clearly plays a critical function in spermatogenesis. The dipeptidase domain of tACE is identical to the C-terminal catalytic domain of somatic ACE (sACE). Bradykinin potentiating peptides (BPPs) from snake venoms are the first natural sACE inhibitors described and their structure–activity relationship studies were the basis for the development of antihypertensive drugs such as captopril. In recent years, it has been showed that a number of BPPs – including BPP-10c – are able to distinguish between the N- and C-active sites of sACE, what is not applicable to captopril. Considering the similarity between tACE and sACE (and since BPPs are able to distinguish between the two active sites of sACE), the effects of the BPP-10c and captopril on the structure and function of the seminiferous epithelium were characterized in the present study. BPP-10c and captopril were administered in male Swiss mice by intraperitoneal injection (4.7 μmol/kg for 15 days) and histological sections of testes were analyzed. Classification of seminiferous tubules and stage analysis were carried out for quantitative evaluation of germ cells of the seminiferous epithelium. The blood-testis barrier (BTB) permeability and distribution of claudin-1 in the seminiferous epithelium were analyzed by hypertonic fixative method and immunohistochemical analyses of testes, respectively. Results The morphology of seminiferous tubules from animals treated with BPP-10c showed an intense disruption of the epithelium, presence of atypical multinucleated cells in the lumen and degenerated germ cells in the adluminal compartment. BPP-10c led to an increase in the number of round spermatids and total support capacity of Sertoli cell in stages I, V, VII/VIII of the seminiferous epithelium cycle, without

  6. Osmotic gradient dependence of osmotic water permeability in rabbit proximal convoluted tubule.

    PubMed

    Berry, C A; Verkman, A S

    1988-10-01

    To assess steady-state transepithelial osmotic water permeability (Pf), rabbit proximal convoluted tubules were perfused in vitro with the impermeant salt, sodium isethionate at 26 degrees C. Osmotic gradients (delta pi) were established by varying the bath concentration of the impermeant solute, raffinose. When lumen osmolality was 300 mOsm and bath osmolality was 320, 360 and 400 mOsm, apparent Pf decreased from 0.5 to 0.10 to 0.08 cm/sec, respectively. Similar data were obtained when lumen osmolality was 400 mOsm. Five possible causes of the delta pi dependence of apparent Pf were considered experimentally and/or theoretically: (1) external unstirred layer (USL); (2) cytoplasmic USL; (3) change in surface area; (4) saturation of water transport; (5) down-regulation of Pf. Apparent Pf was inhibited 83% by p-chloromercuribenzene sulfonate (pCMBS) at 20 mOsm, but not at 60 mOsm delta pi, suggesting presence of a serial barrier resistance to water transport. Increases in perfusate or bath solution flow rate and viscosity did not alter apparent Pf, ruling out an external USL. A simple cytoplasmic USL, described by a constant USL thickness and solute diffusion coefficient, could not account for the delta pi dependence of apparent Pf according to a mathematical model. The activation energy (Ea) for apparent Pf increased from 7.0 to 12.5 kcal/mol when delta pi was increased from 20 to 60 mOsm, not consistent with a simple USL or a change in membrane surface area with transepithelial water flow. These findings are most consistent with a complex cytoplasmic USL, where the average solute diffusion coefficient and/or the area available for osmosis decrease with increasing delta pi. These results (1) indicate that true Pf (at physiologically low delta pi) is very high (greater than 0.5 cm/sec) in the rabbit proximal tubule; (2) provide an explanation for the wide variation in Pf values reported in the literature using different delta pi, and (3) suggest the presence of a

  7. Oxidative stress limits vitamin D metabolism by bovine proximal tubule cells in vitro.

    PubMed

    Crivello, J F

    1988-05-01

    When bovine proximal tubule cells are placed in primary culture, they are subject to elevated oxidative stress which acts to limit the expression of mitochondrial vitamin D3 1 alpha- and 24-hydroxylase activities. This increased oxidative stress was demonstrated by increased production of cell and mitochondrial membrane lipid hyperperoxides (LOOH). This increased production was prevented by the addition of the antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Cell and mitochondrial membrane LOOH increased from 1 to 2 pmol/mg protein on the day of plating to 70-90 pmol/mg protein after 6 days in culture. Pretreatment of cultures with BHA and BHT resulted in membrane LOOH of 15-20 pmol/mg protein after 6 days. Mitochondrial LOOH production was greater than total cell LOOH after 6 days. The increase in cellular oxidative stress was paralleled by decreases in both 1 alpha- and 24-hydroxylase activities toward 25-OH D3. Mitochondrial hydroxylase activities were inversely proportional to the increase in mitochondrial membrane LOOH production. Mitochondrial cytochrome P-450 content, determined spectrophotometrically, was decreased over time in culture. Mitochondrial cytochrome P-450 content determined by a specific polyclonal antibody in an enzyme-linked immunosorbant assay also decreased over time in culture. Specificity of polyclonal antibodies, raised against rat liver microsomal cytochrome P-450 RLM5, was demonstrated by the immunosequestration of both 1 alpha- and 24-hydroxylase activities from a partially purified preparation of renal mitochondrial cytochrome P-450. BHA showed the loss of 1 alpha- and 24-hydroxylase activities and mitochondrial P-450 content measured by all criteria. These experiments indicate that oxidative stress-mediated changes in hydroxylase activities are mediated directly by changes in hydroxylase content and not at distal sites. A partially purified preparation of bovine proximal tubule mitochondrial cytochrome

  8. Distribution of Aedes mosquitoes in the Kilimanjaro Region of northern Tanzania.

    PubMed

    Hertz, Julian T; Lyaruu, Lucille J; Ooi, Eng Eong; Mosha, Franklin W; Crump, John A

    2016-05-01

    Little is known about the presence and distribution of Aedes mosquitoes in northern Tanzania despite the occurence of viruses transmitted by these mosquitoes such as Chikungunya virus (CHIKV) and Dengue virus (DENV) in the region. Adult and larval mosquitoes were collected from rural and urban settings across a wide range of altitudes in the Kilimanjaro Region using the Mosquito Magnet CO2 Trap for collection of adults and old tires for breeding of larvae. Polymerase chain reaction assays were performed on captured adult mosquitoes to detect the presence of CHIKV and DENV. A total of 2609 Aedes aegypti adult mosquitoes were collected; no other Aedes species larvae were found. Mosquito yields were significantly higher in urban settings than rural settings (26.5 vs. 1.9 mosquitoes per day, p = 0.037). A total of 6570 Ae. aegypti larvae were collected from old tires; no other Aedes species larvae were found. Of the 2609 adult mosquitoes collected, none tested positive for CHIKV or DENV. As far as we are aware, this paper reports for the first time the presence of Ae. aegypti in the Kilimanjaro Region of northern Tanzania. Although CHIKV and DENV were not isolated from any of the collected mosquitoes in this study, the apparent absence of other Aedes species in the area suggests that Ae. aegypti is the primary local vector of these infections. PMID:27376502

  9. Aedes albopictus and Its Environmental Limits in Europe.

    PubMed

    Cunze, Sarah; Kochmann, Judith; Koch, Lisa K; Klimpel, Sven

    2016-01-01

    The Asian tiger mosquito Aedes albopictus, native to South East Asia, is listed as one of the worst invasive vector species worldwide. In Europe the species is currently restricted to Southern Europe, but due to the ongoing climate change, Ae. albopictus is expected to expand its potential range further northwards. In addition to modelling the habitat suitability for Ae. albopictus under current and future climatic conditions in Europe by means of the maximum entropy approach, we here focused on the drivers of the habitat suitability prediction. We explored the most limiting factors for Aedes albopictus in Europe under current and future climatic conditions, a method which has been neglected in species distribution modelling so far. Ae. albopictus is one of the best-studied mosquito species, which allowed us to evaluate the applied Maxent approach for most limiting factor mapping. We identified three key limiting factors for Ae. albopictus in Europe under current climatic conditions: winter temperature in Eastern Europe, summer temperature in Southern Europe. Model findings were in good accordance with commonly known establishment thresholds in Europe based on climate chamber experiments and derived from the geographical distribution of the species. Under future climatic conditions low winter temperature were modelled to remain the most limiting factor in Eastern Europe, whereas in Central Europe annual mean temperature and summer temperatures were modelled to be replaced by summer precipitation, respectively, as most limiting factors. Changes in the climatic conditions in terms of the identified key limiting factors will be of great relevance regarding the invasive potential of the Ae. albopictus. Thus, our results may help to understand the key drivers of the suggested range expansion under climate change and may help to improve monitoring programmes. The applied approach of investigating limiting factors has proven to yield valuable results and may also provide

  10. Spermatogenesis-associated proteins at different developmental stages of buffalo testicular seminiferous tubules identified by comparative proteomic analysis.

    PubMed

    Huang, Yu-Lin; Fu, Qiang; Pan, Hong; Chen, Fu-Mei; Zhao, Xiu-Ling; Wang, Huan-Jing; Zhang, Peng-Fei; Huang, Feng-Ling; Lu, Yang-Qing; Zhang, Ming

    2016-07-01

    The testicular seminiferous tubules contain Sertoli cells and different types of spermatogenic cells. They provide the microenvironment for spermatogenesis, but the precise molecular mechanism of spermatogenesis is still not well known. Here, we have employed tandem mass tag coupled to LC-MS/MS with the high-throughput quantitative proteomics technology to explore the protein expression from buffalo testicular seminiferous tubules at three different developmental stages (prepuberty, puberty, and postpuberty). The results show 304 differentially expressed proteins with a ≥2-fold change, and bioinformatics analysis indicates that 27 of these may be associated with spermatogenesis. Expression patterns of seven selected proteins were verified via Western blot and quantitative RT-PCR analysis, and further cellular localizations of these proteins by immunohistochemical or immunofluorescence analysis. Taken together, the results provide potential molecular markers of spermatogenesis and provide a rich resource for further studies on male reproduction regulation. PMID:27173832

  11. Protective Effect of Urtica dioica L. (Urticaceae) on Morphometric and Morphologic Alterations of Seminiferous Tubules in STZ Diabetic Rats

    PubMed Central

    Golalipour, Mohammad Jafar; Kabiri Balajadeh, Babak; Ghafari, Soraya; Azarhosh, Ramin; Khori, Vahid

    2011-01-01

    Objective(s) Urtica dioica L. has been known as a medicinal plant in the world. This study was conducted to determine the effects of the hydroalcoholic extract of Urtica dioica leaves on seminiferous tubules of diabetic rats. Materials and Methods Animals were allocated to control, diabetic and protective groups. Treated animals received extract of U. dioica (100 mg/ kg/ day) IP for the first 5 days and STZ injection on the 6th day. After 5 weeks, testes removed and stained with H&E technique. Results Tubular cell disintegration, sertoli and spermatogonia cell vacuolization, and decrease in sperm concentration observed in diabetic in comparison with control and protective groups. External seminiferous tubular diameter and seminiferous epithelial height significantly reduced (P< 0.05) in diabetic compared with controls, and these parameters increased (P< 0.05) in the treated compared with diabetics. Conclusion Hydroalcoholic extract of U. dioica, before induction of diabetes; has protective role on seminiferous tubules alterations. PMID:23493848

  12. A Systems Level Analysis of Vasopressin-mediated Signaling Networks in Kidney Distal Convoluted Tubule Cells

    PubMed Central

    Cheng, Lei; Wu, Qi; Kortenoeven, Marleen L. A.; Pisitkun, Trairak; Fenton, Robert A.

    2015-01-01

    The kidney distal convoluted tubule (DCT) plays an essential role in maintaining body sodium balance and blood pressure. The major sodium reabsorption pathway in the DCT is the thiazide-sensitive NaCl cotransporter (NCC), whose functions can be modulated by the hormone vasopressin (VP) acting via uncharacterized signaling cascades. Here we use a systems biology approach centered on stable isotope labeling by amino acids in cell culture (SILAC) based quantitative phosphoproteomics of cultured mouse DCT cells to map global changes in protein phosphorylation upon acute treatment with a VP type II receptor agonist 1-desamino-8-D-arginine vasopressin (dDAVP). 6330 unique proteins, containing 12333 different phosphorylation sites were identified. 185 sites were altered in abundance following dDAVP. Basophilic motifs were preferential targets for upregulated sites upon dDAVP stimulation, whereas proline-directed motifs were prominent for downregulated sites. Kinase prediction indicated that dDAVP increased AGC and CAMK kinase families’ activities and decreased activity of CDK and MAPK families. Network analysis implicated phosphatidylinositol-4,5-bisphosphate 3-kinase or CAMKK dependent pathways in VP-mediated signaling; pharmacological inhibition of which significantly reduced dDAVP induced increases in phosphorylated NCC at an activating site. In conclusion, this study identifies unique VP signaling cascades in DCT cells that may be important for regulating blood pressure. PMID:26239621

  13. Proximal tubule-specific glutamine synthetase deletion alters basal and acidosis-stimulated ammonia metabolism.

    PubMed

    Lee, Hyun-Wook; Osis, Gunars; Handlogten, Mary E; Lamers, Wouter H; Chaudhry, Farrukh A; Verlander, Jill W; Weiner, I David

    2016-06-01

    Glutamine synthetase (GS) catalyzes the recycling of NH4 (+) with glutamate to form glutamine. GS is highly expressed in the renal proximal tubule (PT), suggesting ammonia recycling via GS could decrease net ammoniagenesis and thereby limit ammonia available for net acid excretion. The purpose of the present study was to determine the role of PT GS in ammonia metabolism under basal conditions and during metabolic acidosis. We generated mice with PT-specific GS deletion (PT-GS-KO) using Cre-loxP techniques. Under basal conditions, PT-GS-KO increased urinary ammonia excretion significantly. Increased ammonia excretion occurred despite decreased expression of key proteins involved in renal ammonia generation. After the induction of metabolic acidosis, the ability to increase ammonia excretion was impaired significantly by PT-GS-KO. The blunted increase in ammonia excretion occurred despite greater expression of multiple components of ammonia generation, including SN1 (Slc38a3), phosphate-dependent glutaminase, phosphoenolpyruvate carboxykinase, and Na(+)-coupled electrogenic bicarbonate cotransporter. We conclude that 1) GS-mediated ammonia recycling in the PT contributes to both basal and acidosis-stimulated ammonia metabolism and 2) adaptive changes in other proteins involved in ammonia metabolism occur in response to PT-GS-KO and cause an underestimation of the role of PT GS expression. PMID:27009341

  14. Human proximal tubule epithelial cells cultured on hollow fibers: living membranes that actively transport organic cations.

    PubMed

    Jansen, J; De Napoli, I E; Fedecostante, M; Schophuizen, C M S; Chevtchik, N V; Wilmer, M J; van Asbeck, A H; Croes, H J; Pertijs, J C; Wetzels, J F M; Hilbrands, L B; van den Heuvel, L P; Hoenderop, J G; Stamatialis, D; Masereeuw, R

    2015-01-01

    The bioartificial kidney (BAK) aims at improving dialysis by developing 'living membranes' for cells-aided removal of uremic metabolites. Here, unique human conditionally immortalized proximal tubule epithelial cell (ciPTEC) monolayers were cultured on biofunctionalized MicroPES (polyethersulfone) hollow fiber membranes (HFM) and functionally tested using microfluidics. Tight monolayer formation was demonstrated by abundant zonula occludens-1 (ZO-1) protein expression along the tight junctions of matured ciPTEC on HFM. A clear barrier function of the monolayer was confirmed by limited diffusion of FITC-inulin. The activity of the organic cation transporter 2 (OCT2) in ciPTEC was evaluated in real-time using a perfusion system by confocal microscopy using 4-(4-(dimethylamino)styryl)-N-methylpyridinium iodide (ASP(+)) as a fluorescent substrate. Initial ASP(+) uptake was inhibited by a cationic uremic metabolites mixture and by the histamine H2-receptor antagonist, cimetidine. In conclusion, a 'living membrane' of renal epithelial cells on MicroPES HFM with demonstrated active organic cation transport was successfully established as a first step in BAK engineering. PMID:26567716

  15. A Model of Peritubular Capillary Control of Isotonic Fluid Reabsorption by the Renal Proximal Tubule

    PubMed Central

    Deen, W. M.; Robertson, C. R.; Brenner, B. M.

    1973-01-01

    A mathematical model of peritubular transcapillary fluid exchange has been developed to investigate the role of the peritubular environment in the regulation of net isotonic fluid transport across the mammalian renal proximal tubule. The model, derived from conservation of mass and the Starling transcapillary driving forces, has been used to examine the quantitative effects on proximal reabsorption of changes in efferent arteriolar protein concentration and plasma flow rate. Under normal physiological conditions, relatively small perturbations in protein concentration are predicted to influence reabsorption more than even large variations in plasma flow, a prediction in close accord with recent experimental observations in the rat and dog. Changes either in protein concentration or plasma flow have their most pronounced effects when the opposing transcapillary hydrostatic and osmotic pressure differences are closest to equilibrium. Comparison of these theoretical results with variations in reabsorption observed in micropuncture studies makes it possible to place upper and lower bounds on the difference between interstitial oncotic and hydrostatic pressures in the renal cortex of the rat. PMID:4696761

  16. Update on Mechanisms of Renal Tubule Injury Caused by Advanced Glycation End Products

    PubMed Central

    Sun, Hong; Yuan, Yang; Sun, Zilin

    2016-01-01

    Diabetic nephropathy (DN) caused by advanced glycation end products (AGEs) may be associated with lipid accumulation in the kidneys. This study was designed to investigate whether Nε-(carboxymethyl) lysine (CML, a member of the AGEs family) increases lipid accumulation in a human renal tubular epithelial cell line (HK-2) via increasing cholesterol synthesis and uptake and reducing cholesterol efflux through endoplasmic reticulum stress (ERS). Our results showed that CML disrupts cholesterol metabolism in HK-2 cells by activating sterol regulatory element-binding protein 2 (SREBP-2) and liver X receptor (LXR), followed by an increase in 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR) mediated cholesterol synthesis and low density lipoprotein receptor (LDLr) mediated cholesterol uptake and a reduction in ATP-binding cassette transporter A1 (ABCA1) mediated cholesterol efflux, ultimately causing lipid accumulation in HK-2 cells. All of these responses could be suppressed by an ERS inhibitor, which suggests that CML causes lipid accumulation in renal tubule cells through ERS and that the inhibition of ERS is a potential novel approach to treating CML-induced renal tubular foam cell formation. PMID:27034941

  17. In vitro safety assessment of food ingredients in canine renal proximal tubule cells.

    PubMed

    Koči, J; Jeffery, B; Riviere, J E; Monteiro-Riviere, N A

    2015-03-01

    In vitro models are useful tools to initially assess the toxicological safety hazards of food ingredients. Toxicities of cinnamaldehyde (CINA), cinnamon bark oil, lemongrass oil (LGO), thymol, thyme oil (TO), clove leaf oil, eugenol, ginger root extract (GRE), citric acid, guanosine monophosphate, inosine monophosphate and sorbose (SORB) were assessed in canine renal proximal tubule cells (CPTC) using viability assay and renal injury markers. At LC50, CINA was the most toxic (0.012mg/ml), while SORB the least toxic (>100mg/ml). Toxicities (LC50) of positive controls were as follows: 4-aminophenol (0.15mg/ml in CPTC and 0.083mg/ml in human PTC), neomycin (28.6mg/ml in CPTC and 27.1mg/ml in human PTC). XYL displayed lowest cytotoxic potency (LC50=82.7mg/ml in CPTC). In vivo renal injury markers in CPTC were not significantly different from controls. The LGO toxicity mechanism was analyzed using qPCR and electron microscopy. Out of 370 genes, 57 genes (15.4%) were significantly up (34, 9.1%) or down (23, 6.2%) regulated, with the most upregulated gene gsta3 (∼200-fold) and the most affected pathway being oxidative stress. LGO induced damage of mitochondria, phospholipid accumulation and lack of a brush border. Viability assays along with mechanistic studies in the CPTC model may serve as a valuable in vitro toxicity screening tool. PMID:25458622

  18. Axial heterogeneity of intracellular pH in rat proximal convoluted tubule.

    PubMed Central

    Pastoriza-Munoz, E; Harrington, R M; Graber, M L

    1987-01-01

    In the proximal convoluted tubule (PT), the HCO3- reabsorptive rate is higher in early (EPS) compared with late proximal segments (LPS). To examine the mechanism of this HCO3- reabsorption profile, intracellular pH (pHi) was measured along the superficial PT of the rat under free-flow and stationary microperfusion using the pH-sensitive fluorescence of 4-methylumbelliferone (4MU). With 4MU superfusion, pHi was found to decline along the PT. Observation with 365-nm excitation revealed that EPS were brightly fluorescent and always emerged away from their star vessel. Midproximal segments were darker and closer to the star vessel which was surrounded by the darkest LPS. Decreasing luminal HCO3- from 15 to 0 mM lowered pHi in both EPS and LPS, but pHi remained more alkaline in EPS with both perfusates. Thus the axial decline in pHi along the PT is due to both luminal factors and intrinsic differences in luminal H+ extrusion in PT cells. PMID:3036912

  19. Mechanism of cisplatin proximal tubule toxicity revealed by integrating transcriptomics, proteomics, metabolomics and biokinetics.

    PubMed

    Wilmes, Anja; Bielow, Chris; Ranninger, Christina; Bellwon, Patricia; Aschauer, Lydia; Limonciel, Alice; Chassaigne, Hubert; Kristl, Theresa; Aiche, Stephan; Huber, Christian G; Guillou, Claude; Hewitt, Philipp; Leonard, Martin O; Dekant, Wolfgang; Bois, Frederic; Jennings, Paul

    2015-12-25

    Cisplatin is one of the most widely used chemotherapeutic agents for the treatment of solid tumours. The major dose-limiting factor is nephrotoxicity, in particular in the proximal tubule. Here, we use an integrated omics approach, including transcriptomics, proteomics and metabolomics coupled to biokinetics to identify cell stress response pathways induced by cisplatin. The human renal proximal tubular cell line RPTEC/TERT1 was treated with sub-cytotoxic concentrations of cisplatin (0.5 and 2 μM) in a daily repeat dose treating regime for up to 14 days. Biokinetic analysis showed that cisplatin was taken up from the basolateral compartment, transported to the apical compartment, and accumulated in cells over time. This is in line with basolateral uptake of cisplatin via organic cation transporter 2 and bioactivation via gamma-glutamyl transpeptidase located on the apical side of proximal tubular cells. Cisplatin affected several pathways including, p53 signalling, Nrf2 mediated oxidative stress response, mitochondrial processes, mTOR and AMPK signalling. In addition, we identified novel pathways changed by cisplatin, including eIF2 signalling, actin nucleation via the ARP/WASP complex and regulation of cell polarization. In conclusion, using an integrated omic approach together with biokinetics we have identified both novel and established mechanisms of cisplatin toxicity. PMID:25450742

  20. Complexity of glutamine metabolism in kidney tubules from fed and fasted rats.

    PubMed Central

    Vercoutère, Barbara; Durozard, Daniel; Baverel, Gabriel; Martin, Guy

    2004-01-01

    Glutamine is an important renal glucose precursor and energy provider. In order to advance our understanding of the underlying metabolic processes, we studied the metabolism of variously labelled [13C]glutamine and [14C]glutamine molecules and the effects of fasting in isolated rat renal proximal tubules. Absolute fluxes through the enzymes involved, including enzymes of four different cycles operating concomitantly, were assessed by combining mainly the 13C NMR data with an appropriate model of glutamine metabolism. In both nutritional states, unidirectional glutamine removal by glutaminase was partially masked by the concomitant operation of glutamine synthetase; fasting accelerated glutamine removal by increasing flux solely through glutaminase, without changing that through glutamine synthetase. Fasting stimulated net glutamate degradation only by decreasing flux through glutamate dehydrogenase in the reductive amination direction, but surprisingly did not significantly alter complete oxidation of the glutamine carbon skeleton. Finally, gluconeogenesis from glutamine involved not only substantial recycling through the tricarboxylic acid cycle, but also an important anaplerotic flux through pyruvate carboxylase that was accelerated dramatically by fasting. Thus renal glutamine metabolism follows an unexpectedly complex route that is precisely regulated during fasting. PMID:14616091

  1. Handling of Drugs, Metabolites, and Uremic Toxins by Kidney Proximal Tubule Drug Transporters

    PubMed Central

    Wu, Wei; Bush, Kevin T.; Hoenig, Melanie P.; Blantz, Roland C.; Bhatnagar, Vibha

    2015-01-01

    The proximal tubule of the kidney plays a crucial role in the renal handling of drugs (e.g., diuretics), uremic toxins (e.g., indoxyl sulfate), environmental toxins (e.g., mercury, aristolochic acid), metabolites (e.g., uric acid), dietary compounds, and signaling molecules. This process is dependent on many multispecific transporters of the solute carrier (SLC) superfamily, including organic anion transporter (OAT) and organic cation transporter (OCT) subfamilies, and the ATP-binding cassette (ABC) superfamily. We review the basic physiology of these SLC and ABC transporters, many of which are often called drug transporters. With an emphasis on OAT1 (SLC22A6), the closely related OAT3 (SLC22A8), and OCT2 (SLC22A2), we explore the implications of recent in vitro, in vivo, and clinical data pertinent to the kidney. The analysis of murine knockouts has revealed a key role for these transporters in the renal handling not only of drugs and toxins but also of gut microbiome products, as well as liver-derived phase 1 and phase 2 metabolites, including putative uremic toxins (among other molecules of metabolic and clinical importance). Functional activity of these transporters (and polymorphisms affecting it) plays a key role in drug handling and nephrotoxicity. These transporters may also play a role in remote sensing and signaling, as part of a versatile small molecule communication network operative throughout the body in normal and diseased states, such as AKI and CKD. PMID:26490509

  2. Differentiated growth of human renal tubule cells on thin-film and nanostructured materials.

    PubMed

    Fissell, William H; Manley, Sargum; Westover, Angela; Humes, H David; Fleischman, Aaron J; Roy, Shuvo

    2006-01-01

    Over 300,000 Americans are dependent on hemodialysis as treatment for renal failure, and kidney transplantation is limited by scarcity of donor organs. This shortage has prompted research into tissue engineering of renal replacement therapy. Existing bioartificial kidneys are large and their use labor intensive, but they have shown improved survival compared to conventional therapy in preclinical studies and an US Food and Drug Administration-approved phase 2 clinical trial. This hybrid technology will require miniaturization of hemofilters, cell culture substrates, sensors, and integration of control electronics. Using the same harvesting and isolation techniques used in preparing bioartificial kidneys for clinical use, we characterized human renal tubule cell growth on a variety of silicon and related thin-film material substrates commonly used in the construction of microelectromechanical systems (MEMS), as well as novel silicon nanopore membranes (SNMs). Human cortical tubular epithelial cells (HCTC) were seeded onto samples of single-crystal silicon, polycrystalline silicon, silicon dioxide, silicon nitride, SU-8 photoresist, SNMs, and polyester tissue culture inserts, and grown to confluence. The cells formed confluent monolayers with tight junctions and central cilia. Transepithelial resistances were similar between SNMs and polyester membranes. The differentiated growth of human tubular epithelial cells on MEMS materials strongly suggests that miniaturization of the existing bioartificial kidney will be feasible, paving the way for widespread application of this novel technology. PMID:16760708

  3. The Endocytic Receptor Megalin and its Associated Proteins in Proximal Tubule Epithelial Cells

    PubMed Central

    De, Shankhajit; Kuwahara, Shoji; Saito, Akihiko

    2014-01-01

    Receptor-mediated endocytosis in renal proximal tubule epithelial cells (PTECs) is important for the reabsorption and metabolization of proteins and other substances, including carrier-bound vitamins and trace elements, in glomerular filtrates. Impairment of this endocytic process results in the loss of such substances and development of proteinuria, which is an important clinical indicator of kidney diseases and is also a risk marker for cardiovascular disease. Megalin, a member of the low-density lipoprotein receptor gene family, is a multiligand receptor expressed in the apical membrane of PTECs and plays a central role in the endocytic process. Megalin interacts with various intracellular adaptor proteins for intracellular trafficking and cooperatively functions with other membrane molecules, including the cubilin-amnionless complex. Evidence suggests that megalin and the cubilin-amnionless complex are involved in the uptake of toxic substances into PTECs, which leads to the development of kidney disease. Studies of megalin and its associated molecules will be useful for future development of novel strategies for the diagnosis and treatment of kidney diseases. PMID:25019425

  4. Stretch-activated channels in single early distal tubule cells of the frog.

    PubMed Central

    Hurst, A M; Hunter, M

    1990-01-01

    1. Single stretch-activated channels have been studied in cell-attached and excised patches from single early distal tubule (diluting segment) cells of Rana temporaria. 2. The channels can be reversibly activated, in both cell-attached and excised patches, by the application of negative pressure to the pipette causing mechanical stretching of the cell membrane. In cell-attached patches, application of 14.8 cmH2O negative pressure to the patch pipette increased reversibly the open probably from 0.11 to 0.87. 3. The channel conductance in the cell-attached configuration with standard Ringer solution in the pipette is 21.3 pS. 4. The channel is non-specific. In excised inside-out patches ion substitution experiments show that the channel does not discriminate between sodium and potassium ions, nor does it appear to select for cations over anions. 5. The channel is voltage sensitive such that depolarizing the cell opens the channel. The open probability at the resting membrane potential, 0.89, was reduced to 0.26 at a hyperpolarizing potential of 100 mV (holding pressure of -20.1 cmH2O or -206 Pa). 6. The sensitivity of the channel to mechanical stretching suggests that the channel may be involved in cell volume regulation. PMID:1707964

  5. Human proximal tubule epithelial cells cultured on hollow fibers: living membranes that actively transport organic cations

    PubMed Central

    Jansen, J.; De Napoli, I. E; Fedecostante, M.; Schophuizen, C. M. S.; Chevtchik, N. V.; Wilmer, M. J.; van Asbeck, A. H.; Croes, H. J.; Pertijs, J. C.; Wetzels, J. F. M.; Hilbrands, L. B.; van den Heuvel, L. P.; Hoenderop, J. G.; Stamatialis, D.; Masereeuw, R.

    2015-01-01

    The bioartificial kidney (BAK) aims at improving dialysis by developing ‘living membranes’ for cells-aided removal of uremic metabolites. Here, unique human conditionally immortalized proximal tubule epithelial cell (ciPTEC) monolayers were cultured on biofunctionalized MicroPES (polyethersulfone) hollow fiber membranes (HFM) and functionally tested using microfluidics. Tight monolayer formation was demonstrated by abundant zonula occludens-1 (ZO-1) protein expression along the tight junctions of matured ciPTEC on HFM. A clear barrier function of the monolayer was confirmed by limited diffusion of FITC-inulin. The activity of the organic cation transporter 2 (OCT2) in ciPTEC was evaluated in real-time using a perfusion system by confocal microscopy using 4-(4-(dimethylamino)styryl)-N-methylpyridinium iodide (ASP+) as a fluorescent substrate. Initial ASP+ uptake was inhibited by a cationic uremic metabolites mixture and by the histamine H2-receptor antagonist, cimetidine. In conclusion, a ‘living membrane’ of renal epithelial cells on MicroPES HFM with demonstrated active organic cation transport was successfully established as a first step in BAK engineering. PMID:26567716

  6. Handling of Drugs, Metabolites, and Uremic Toxins by Kidney Proximal Tubule Drug Transporters.

    PubMed

    Nigam, Sanjay K; Wu, Wei; Bush, Kevin T; Hoenig, Melanie P; Blantz, Roland C; Bhatnagar, Vibha

    2015-11-01

    The proximal tubule of the kidney plays a crucial role in the renal handling of drugs (e.g., diuretics), uremic toxins (e.g., indoxyl sulfate), environmental toxins (e.g., mercury, aristolochic acid), metabolites (e.g., uric acid), dietary compounds, and signaling molecules. This process is dependent on many multispecific transporters of the solute carrier (SLC) superfamily, including organic anion transporter (OAT) and organic cation transporter (OCT) subfamilies, and the ATP-binding cassette (ABC) superfamily. We review the basic physiology of these SLC and ABC transporters, many of which are often called drug transporters. With an emphasis on OAT1 (SLC22A6), the closely related OAT3 (SLC22A8), and OCT2 (SLC22A2), we explore the implications of recent in vitro, in vivo, and clinical data pertinent to the kidney. The analysis of murine knockouts has revealed a key role for these transporters in the renal handling not only of drugs and toxins but also of gut microbiome products, as well as liver-derived phase 1 and phase 2 metabolites, including putative uremic toxins (among other molecules of metabolic and clinical importance). Functional activity of these transporters (and polymorphisms affecting it) plays a key role in drug handling and nephrotoxicity. These transporters may also play a role in remote sensing and signaling, as part of a versatile small molecule communication network operative throughout the body in normal and diseased states, such as AKI and CKD. PMID:26490509

  7. Premeiotic germ cell defect in seminiferous tubules of Atm-null testis

    SciTech Connect

    Takubo, Keiyo . E-mail: keiyot@gmail.com; Hirao, Atsushi; Ohmura, Masako; Azuma, Masaki; Arai, Fumio; Nagamatsu, Go; Suda, Toshio . E-mail: sudato@sc.itc.keio.ac.jp

    2006-12-29

    Lifelong spermatogenesis is maintained by coordinated sequential processes including self-renewal of stem cells, proliferation of spermatogonial cells, meiotic division, and spermiogenesis. It has been shown that ataxia telangiectasia-mutated (ATM) is required for meiotic division of the seminiferous tubules. Here, we show that, in addition to its role in meiosis, ATM has a pivotal role in premeiotic germ cell maintenance. ATM is activated in premeiotic spermatogonial cells and the Atm-null testis shows progressive degeneration. In Atm-null testicular cells, differing from bone marrow cells of Atm-null mice, reactive oxygen species-mediated p16{sup Ink4a} activation does not occur in Atm-null premeiotic germ cells, which suggests the involvement of different signaling pathways from bone marrow defects. Although Atm-null bone marrow undergoes p16{sup Ink4a}-mediated cellular senescence program, Atm-null premeiotic germ cells exhibited cell cycle arrest and apoptotic elimination of premeiotic germ cells, which is different from p16{sup Ink4a}-mediated senescence.

  8. A Systems Level Analysis of Vasopressin-mediated Signaling Networks in Kidney Distal Convoluted Tubule Cells.

    PubMed

    Cheng, Lei; Wu, Qi; Kortenoeven, Marleen L A; Pisitkun, Trairak; Fenton, Robert A

    2015-01-01

    The kidney distal convoluted tubule (DCT) plays an essential role in maintaining body sodium balance and blood pressure. The major sodium reabsorption pathway in the DCT is the thiazide-sensitive NaCl cotransporter (NCC), whose functions can be modulated by the hormone vasopressin (VP) acting via uncharacterized signaling cascades. Here we use a systems biology approach centered on stable isotope labeling by amino acids in cell culture (SILAC) based quantitative phosphoproteomics of cultured mouse DCT cells to map global changes in protein phosphorylation upon acute treatment with a VP type II receptor agonist 1-desamino-8-D-arginine vasopressin (dDAVP). 6330 unique proteins, containing 12333 different phosphorylation sites were identified. 185 sites were altered in abundance following dDAVP. Basophilic motifs were preferential targets for upregulated sites upon dDAVP stimulation, whereas proline-directed motifs were prominent for downregulated sites. Kinase prediction indicated that dDAVP increased AGC and CAMK kinase families' activities and decreased activity of CDK and MAPK families. Network analysis implicated phosphatidylinositol-4,5-bisphosphate 3-kinase or CAMKK dependent pathways in VP-mediated signaling; pharmacological inhibition of which significantly reduced dDAVP induced increases in phosphorylated NCC at an activating site. In conclusion, this study identifies unique VP signaling cascades in DCT cells that may be important for regulating blood pressure. PMID:26239621

  9. Lactic acid is a sperm motility inactivation factor in the sperm storage tubules

    PubMed Central

    Matsuzaki, Mei; Mizushima, Shusei; Hiyama, Gen; Hirohashi, Noritaka; Shiba, Kogiku; Inaba, Kazuo; Suzuki, Tomohiro; Dohra, Hideo; Ohnishi, Toshiyuki; Sato, Yoshikatsu; Kohsaka, Tetsuya; Ichikawa, Yoshinobu; Atsumi, Yusuke; Yoshimura, Takashi; Sasanami, Tomohiro

    2015-01-01

    Although successful fertilization depends on timely encounters between sperm and egg, the decoupling of mating and fertilization often confers reproductive advantages to internally fertilizing animals. In several vertebrate groups, postcopulatory sperm viability is prolonged by storage in specialized organs within the female reproductive tract. In birds, ejaculated sperm can be stored in a quiescent state within oviductal sperm storage tubules (SSTs), thereby retaining fertilizability for up to 15 weeks at body temperature (41 °C); however, the mechanism by which motile sperm become quiescent within SSTs is unknown. Here, we show that low oxygen and high lactic acid concentrations are established in quail SSTs. Flagellar quiescence was induced by lactic acid in the concentration range found in SSTs through flagellar dynein ATPase inactivation following cytoplasmic acidification (

  10. Effects of D-amino acid substituents on degradation of LHRH analogues by proximal tubule

    SciTech Connect

    Flouret, G.; Majewski, T.; Peterson, D.R.; Kenny, A.J.; Carone, F.A.

    1987-03-01

    The luteinizing hormone-releasing hormone, LHRH, is degraded in renal proximal tubules (PT) in vivo (rat) and in vitro (rabbit) to < Glu-His (2), < Glu-His-Trp (3), and < Glu-His-Trp-Ser (4). LHRH may be cleaved by endopeptidases simultaneously at multiple bonds, or initially at Ser/sup 4/-Try/sup 5/ followed by carboxypeptidase hydrolysis of 4 to 3 and then 2. To distinguish between these mechanisms, (/sup 3/H)LHRH analogues were incubated with rabbit renal brush-border membranes (BBM), microinfused into PT in vivo or in vitro, and products were analyzed by HPLC. (D-Ser/sup 4/)LHRH was not cleaved at D-Ser/sup 4/-Try/sup 5/ but yielded < Glu-His-Trp-D-Ser-Tyr-Gly as the major metabolite plus 2 and 3. (D-Trp/sup 6/)LHRH was cleaved by BBM and PT to 2 and 3, but not to 4. (D-Ser/sup 4/, D-Trp/sup 6/)LHRH was not cleaved by BBM, but was degraded to 2 by PT in vivo. Thus, D-amino acid substituents altered the expected cleavage pattern of these analogues. Thus, normally LHRH may be cleaved in PT by endopeptidase-24.11 to 2 and 4, and by angiotensin I-converting enzyme to 3, its know cleavage site.

  11. Effect of ADH on rubidium transport in isolated perfused rat cortical collecting tubules

    SciTech Connect

    Schafer, J.A.; Troutman, S.L.

    1986-06-01

    Unidirectional fluxes of 86Rb+ were measured as an indicator of potassium transport in isolated rat cortical collecting tubules perfused and bathed at 38 degrees C with isotonic solutions in which Rb+ replaced K+. Under control conditions the lumen-to-bath flux (Jl----b) was significantly less than the bath-to-lumen flux (Jb----l), indicating net Rb+ secretion. Net secretion increased approximately 180% after addition of 100 microU/ml of arginine vasopressin (ADH) to the bathing solution, due to a rapid and reversible increase in Jb----l from 4.6 +/- 0.8 to 9.0 +/- 1.9 pmol X min-1 X mm-1 with no significant change in Jl----b. The ADH effect was completely inhibited by 2 mM luminal Ba2+. The average transepithelial voltage (Ve) was not significantly different from zero in the control period but became lumen negative (-5 to -10 mV) after ADH. With 10(-5) M amiloride in the lumen Ve was lumen positive (+2 to +4 mV) and was unaltered by ADH or Ba2+, yet ADH produced a significant but attentuated increase in Jb----l with no change in Jl----b. The results indicate that ADH augments net K+ secretion either by an increase in the Ba2+-sensitive conductance of the apical membrane or by an increase in the electrochemical potential driving force for net Rb+ secretion through this pathway.

  12. How much can the tubule regenerate and who does it? An open question

    PubMed Central

    Lombardi, Duccio; Becherucci, Francesca; Romagnani, Paola

    2016-01-01

    The tubular compartment of the kidney is the primary site of a wide range of insults that can result in acute kidney injury (AKI), a condition associated with high mortality and an increased risk to develop end-stage renal disease. Nevertheless, kidney function is often quickly recovered after tubular injury. How this happens has only partially been unveiled. Indeed, although it has clearly been demonstrated that regenerated epithelial cells arise from survived intratubular cells, the true entity, as well as the cellular source of this regenerative process, remains mostly unknown. Is whichever proximal tubular epithelial cell able to dedifferentiate and divide to replace neighboring lost tubular cells, thus suggesting an extreme regenerative ability of residual tubular epithelium, or is the regenerative potential of tubular epithelium limited, and mostly related to a preexisting population of intratubular scattered progenitor cells which are more resistant to death? Gaining insights on how this process takes place is essential for developing new therapeutic strategies to prevent AKI, as well as AKI-related chronic kidney disease. The aim of this review is to discuss why the answers to these questions are still open, and how further investigations are needed to understand which is the true regenerative potential of the tubule and who are the players that allow functional recovery after AKI. PMID:26175143

  13. Lactic acid is a sperm motility inactivation factor in the sperm storage tubules.

    PubMed

    Matsuzaki, Mei; Mizushima, Shusei; Hiyama, Gen; Hirohashi, Noritaka; Shiba, Kogiku; Inaba, Kazuo; Suzuki, Tomohiro; Dohra, Hideo; Ohnishi, Toshiyuki; Sato, Yoshikatsu; Kohsaka, Tetsuya; Ichikawa, Yoshinobu; Atsumi, Yusuke; Yoshimura, Takashi; Sasanami, Tomohiro

    2015-01-01

    Although successful fertilization depends on timely encounters between sperm and egg, the decoupling of mating and fertilization often confers reproductive advantages to internally fertilizing animals. In several vertebrate groups, postcopulatory sperm viability is prolonged by storage in specialized organs within the female reproductive tract. In birds, ejaculated sperm can be stored in a quiescent state within oviductal sperm storage tubules (SSTs), thereby retaining fertilizability for up to 15 weeks at body temperature (41°C); however, the mechanism by which motile sperm become quiescent within SSTs is unknown. Here, we show that low oxygen and high lactic acid concentrations are established in quail SSTs. Flagellar quiescence was induced by lactic acid in the concentration range found in SSTs through flagellar dynein ATPase inactivation following cytoplasmic acidification (

  14. Midline-derived Shh regulates mesonephric tubule formation through the paraxial mesoderm

    PubMed Central

    Murashima, Aki; Akita, Hiroki; Okazawa, Mika; Kishigami, Satoshi; Nakagata, Naomi; Nishinakamura, Ryuichi; Yamada, Gen

    2014-01-01

    During organogenesis, Sonic hedgehog (Shh) possesses dual functions: Shh emanating from midline structures regulates the positioning of bilateral structures at early stages, whereas organ-specific Shh locally regulates organ morphogenesis at later stages. The mesonephros is a transient embryonic kidney in amniote, whereas it becomes definitive adult kidney in some anamniotes. Thus, elucidating the regulation of mesonephros formation has important implications for our understanding of kidney development and evolution. In Shh knockout (KO) mutant mice, the mesonephros was displaced towards the midline and ectopic mesonephric tubules (MTs) were present in the caudal mesonephros. Mesonephros-specific ablation of Shh in Hoxb7-Cre;Shhflox/− and Sall1CreERT2/+;Shhflox/− mice embryos indicated that Shh expressed in the mesonephros was not required for either the development of the mesonephros or the differentiation of the male reproductive tract. Moreover, stage-specific ablation of Shh in ShhCreERT2/flox mice showed that notochord- and/or floor plate-derived Shh were essential for the regulation of the number and position of MTs. Lineage analysis of hedgehog (Hh)-responsive cells, and analysis of gene expression in Shh KO embryos suggested that Shh regulated nephrogenic gene expression indirectly, possibly through effects on the paraxial mesoderm. These data demonstrate the essential role of midline-derived Shh in local tissue morphogenesis and differentiation. PMID:24370450

  15. Regulation of transport in the connecting tubule and cortical collecting duct

    PubMed Central

    Staruschenko, Alexander

    2012-01-01

    The central goal of this overview article is to summarize recent findings in renal epithelial transport, focusing chiefly on the connecting tubule (CNT) and the cortical collecting duct (CCD). Mammalian CCD and CNT are involved in fine tuning of electrolyte and fluid balance through reabsorption and secretion. Specific transporters and channels mediate vectorial movements of water and solutes in these segments. Although only a small percent of the glomerular filtrate reaches the CNT and CCD, these segments are critical for water and electrolyte homeostasis since several hormones, e.g. aldosterone and arginine vasopressin, exert their main effects in these nephron sites. Importantly, hormones regulate the function of the entire nephron and kidney by affecting channels and transporters in the CNT and CCD. Knowledge about the physiological and pathophysiological regulation of transport in the CNT and CCD and particular roles of specific channels/transporters has increased tremendously over the last two decades. Recent studies shed new light on several key questions concerning the regulation of renal transport. Precise distribution patterns of transport proteins in the CCD and CNT will be reviewed, and their physiological roles and mechanisms mediating ion transport in these segments will be also covered. Special emphasis will be given to pathophysiological conditions appearing as a result of abnormalities in renal transport in the CNT and CCD. PMID:23227301

  16. Push-out bond strength and dentinal tubule penetration of different root canal sealers used with coated core materials

    PubMed Central

    Purali, Nuhan; Coşgun, Erdal; Calt, Semra

    2016-01-01

    Objectives The aim of this study was to compare the push-out bond strength and dentinal tubule penetration of root canal sealers used with coated core materials and conventional gutta-percha. Materials and Methods A total of 72 single-rooted human mandibular incisors were instrumented with NiTi rotary files with irrigation of 2.5% NaOCl. The smear layer was removed with 17% ethylenediaminetetraacetic acid (EDTA). Specimens were assigned into four groups according to the obturation system: Group 1, EndoRez (Ultradent Product Inc.); Group 2, Activ GP (Brasseler); Group 3, SmartSeal (DFRP Ltd. Villa Farm); Group 4, AH 26 (Dentsply de Trey)/gutta-percha (GP). For push-out bond strength measurement, two horizontal slices were obtained from each specimen (n = 20). To compare dentinal tubule penetration, remaining 32 roots assigned to 4 groups as above were obturated with 0.1% Rhodamine B labeled sealers. One horizontal slice was obtained from the middle third of each specimen (n = 8) and scanned under confocal laser scanning electron microscope. Tubule penetration area, depth, and percentage were measured. Kruskall-Wallis test was used for statistical analysis. Results EndoRez showed significantly lower push-out bond strength than the others (p < 0.05). No significant difference was found amongst the groups in terms of percentage of sealer penetration. SmartSeal showed the least penetration than the others (p < 0.05). Conclusions The bond strength and sealer penetration of resin-and glass ionomer-based sealers used with coated core was not superior to resin-based sealer used with conventional GP. Dentinal tubule penetration has limited effect on bond strength. The use of conventional GP with sealer seems to be sufficient in terms of push-out bond strength. PMID:27200279

  17. Fluid reabsorption in proximal convoluted tubules of mice with gene deletions of claudin-2 and/or aquaporin1

    PubMed Central

    Huang, Yuning; Mizel, Diane

    2013-01-01

    Deletions of claudin-2 (Cldn2) and aquaporin1 (AQP1) reduce proximal fluid reabsorption (PFR) by about 30% and 50%, respectively. Experiments were done to replicate these observations and to determine in AQP1/claudin-2 double knockout mice (DKO) if the effects of deletions of these established water pores are additive. PFR was determined in inactin/ketamine-anesthetized mice by free-flow micropuncture using single-nephron I125-iothalamate (io) clearance. Animal means of PFR [% of glomerular filtration rate (GFR)] derived from TF/Piothalamate ratios in 12 mice in each of four groups [wild type (WT), Cldn2−/−, AQP1−/−, and DKO) were 45.8 ± 0.85 (51 tubules), 35.4 ± 1 (54 tubules; P < 0.01 vs. WT), 36.8 ± 1 (63 tubules; P < 0.05 vs. WT), and 33.9 ± 1.4 (69 tubules; P < 0.01 vs. WT). Kidney and single-nephron GFRs (SNGFR) were significantly reduced in all mutant strains. The direct relationship between PFR and SNGFR was maintained in mutant mice, but the slope of this relationship was reduced in the absence of Cldn2 and/or AQP1. Transtubular osmotic pressure differences were not different between WT and Cldn2−/− mice, but markedly increased in DKO. In conclusion, the deletion of Cldn2, AQP1, or of both Cldn2 and AQP1 reduces PFR by 22.7%, 19.6%, and 26%, respectively. Our data are consistent with an up to 25% paracellular contribution to PFR. The reduced osmotic water permeability caused by absence of AQP1 augments luminal hypotonicity. Aided by a fall in filtered load, the capacity of non-AQP1-dependent transcellular reabsorption is sufficient to maintain PFR without AQP1 and claudin-2 at 75% of control. PMID:24049145

  18. Vimentin metaplasia in renal cortical tubules of preneoplastic, neoplastic, aging, and regenerative lesions of rats and humans.

    PubMed Central

    Ward, J. M.; Stevens, J. L.; Konishi, N.; Kurata, Y.; Uno, H.; Diwan, B. A.; Ohmori, T.

    1992-01-01

    Vimentin expression was studied immunohistochemically in renal cortical tubules of untreated male rats of various ages, rats exposed to toxins (barbital sodium, folic acid) and carcinogens (streptozotocin, N-bis(2-hydroxypropyl)nitrosamine, barbital sodium, and in humans of various ages with or without renal epithelial tumors. Fetal, neonatal, and young adult rats did not express vimentin in renal cortical tubules. Regenerative renal tubular lesions from rats with aging nephropathy and from rats with toxic nephropathy both expressed vimentin. Mitogenic lesions induced by folic acid at 24 hours, however, were not immunoreactive for vimentin. Carcinogen-induced preneoplastic renal cortical tubular lesions in rats were most often focally immunoreactive whereas strong vimentin expression was found in almost all induced renal tumors. In kidneys of three children (younger than 2 years of age), vimentin was not found in renal cortical tubular cells except in rare individual cells in one case. Vimentin was abundant in basophilic regenerative tubules in kidneys of aged individuals, however. Most (7/10) human renal carcinomas and latent preneoplastic or neoplastic renal tubular lesions found incidentally at autopsy (2/4) showed vimentin expression. The authors suggest that the switching to vimentin expression in phenotypically normal renal cortical tubular cells in rats and humans, which do not usually express the intermediate filament protein vimentin, should be considered vimentin metaplasia. Vimentin expression is dissociated from increased cell proliferation in hyperplastic and neoplastic lesions, however. Instead the degree of dedifferentiation of the tubule cells and changes in phenotype were associated with vimentin expression. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 PMID:1415487

  19. Winter Refuge for Aedes aegypti and Ae. albopictus Mosquitoes in Hanoi during Winter

    PubMed Central

    Tsunoda, Takashi; Cuong, Tran Chi; Dong, Tran Duc; Yen, Nguyen Thi; Le, Nguyen Hoang; Phong, Tran Vu; Minakawa, Noboru

    2014-01-01

    Dengue occurs throughout the year in Hanoi, Vietnam, despite winter low temperatures <10°C. During July 2010 to March 2012, we surveyed monthly for Aedes larvae and pupae in 120 houses in 8 Hanoi districts. Aedes albopictus preferred discarded containers in summer and pupal density drastically decreased in winter. Aedes aegypti preferred concrete tanks and this preference increased in winter. Even in winter, the lowest water temperature found in concrete tanks was >14°C, exceeding the developmental zero point of Ae. aegypti. Although jars, drums and concrete tanks were the dominant containers previously (1994–97) in Hanoi, currently the percentage of residences with concrete tanks was still high while jars and drums were quite low. Our study showed that concrete tanks with broken lids allowing mosquitoes access were important winter refuge for Ae. aegypti. We also indicate a concern about concrete tanks serving as foci for Ae. aegypti to expand their distribution in cooler regions. PMID:24752230

  20. Innate Cellular Immune Responses in Aedes caspius (Diptera: Culicidae) Mosquitoes.

    PubMed

    Soliman, D E; Farid, H A; Hammad, R E; Gad, A M; Bartholomay, L C

    2016-03-01

    Mosquitoes transmit a variety of pathogens that have devastating consequences for global public and veterinary health. Despite their capacity to serve as vectors, these insects have a robust capacity to respond to invading organisms with strong cellular and humoral immune responses. In Egypt, Aedes caspius (Pallas, 1771) has been suspected to act as a bridge vector of Rift Valley Fever virus between animals and humans. Microscopic analysis of Ae. caspius hemolymph revealed the presence of phagocytic cells called granulocytes. We further evaluated cellular immune responses produced by Ae. caspius as a result of exposure to a Gram-negative, and Gram-positive bacterium, and to latex beads. After challenge, a rapid and strong phagocytic response against either a natural or synthetic invader was evident. Hemocyte integrity in bacteria-inoculated mosquitoes was not morphologically affected. The number of circulating granulocytes decreased with age, reducing the overall phagocytic capacity of mosquitoes over time. The magnitude and speed of the phagocytic response suggested that granulocytes act as an important force in the battle against foreign invaders, as has been characterized in other important mosquito vector species. PMID:26792848

  1. Intriguing olfactory proteins from the yellow fever mosquito, Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Ishida, Yuko; Chen, Angela M.; Tsuruda, Jennifer M.; Cornel, Anthon J.; Debboun, Mustapha; Leal, Walter S.

    2004-09-01

    Four antennae-specific proteins (AaegOBP1, AaegOBP2, AaegOBP3, and AaegASP1) were isolated from the yellow fever mosquito, Aedes aegypti and their full-length cDNAs were cloned. RT-PCR indicated that they are expressed in female and, to a lesser extent, in male antennae, but not in control tissues (legs). AaegOBP1 and AaegOBP3 showed significant similarity to previously identified mosquito odorant-binding proteins (OBPs) in cysteine spacing pattern and sequence. Two of the isolated proteins have a total of eight cysteine residues. The similarity of the spacing pattern of the cysteine residues and amino acid sequence to those of previously identified olfactory proteins suggests that one of the cysteine-rich proteins (AaegOBP2) is an OBP. The other (AaegASP1) did not belong to any group of known OBPs. Structural analyses indicate that six of the cysteine residues in AaegOBP2 are linked in a similar pattern to the previously known cysteine pairing in OBPs, i.e., Cys-24 Cys-55, Cys-51 Cys-104, Cys-95 Cys-113. The additional disulfide bridge, Cys-38 Cys-125, knits the extended C-terminal segment of the protein to a predicted α2-helix. As indicated by circular dichroism (CD) spectra, the extra rigidity seems to prevent the predicted formation of a C-terminal α-helix at low pH.

  2. Functional Development of the Octenol Response in Aedes aegypti

    PubMed Central

    Bohbot, Jonathan D.; Durand, Nicolas F.; Vinyard, Bryan T.; Dickens, Joseph C.

    2013-01-01

    Attraction of female Aedes aegypti mosquitoes to 1-octen-3-ol (octenol), CO2, lactic acid, or ammonia emitted by vertebrate hosts is not only contingent on the presence of odorants in the environment, but is also influenced by the insect’s physiological state. For anautogenous mosquito species, like A. aegypti, newly emerged adult females neither respond to host odors nor engage in blood-feeding; the bases for these behaviors are poorly understood. Here we investigated detection of two components of an attractant blend emitted by vertebrate hosts, octenol, and CO2, by female A. aegypti mosquitoes using electrophysiological, behavioral, and molecular approaches. An increase in sensitivity of octenol olfactory receptor neurons (ORNs) was correlated with an increase in odorant receptor gene (Or) expression and octenol-mediated attractive behavior from day 1 to day 6 post-emergence. While the sensitivity of octenol ORNs was maintained through day 10, behavioral responses to octenol decreased as did the ability of females to discriminate between octenol and octenol + CO2. Our results show differing age-related roles for the peripheral receptors for octenol and higher order neural processing in the behavior of female mosquitoes. PMID:23471139

  3. Standardized Laboratory Feeding of Larval Aedes japonicus japonicus (Diptera: Culicidae)

    PubMed Central

    Bock, Friederike; Kuch, Ulrich; Pfenninger, Markus; Müller, Ruth

    2015-01-01

    The Asian bush mosquito (Aedes japonicus japonicus, Theobald 1901) is an invasive culicid species which originates in Asia but is nowadays present in northern America and Europe. It is a competent vector for several human disease pathogens. In addition to the public health threat, this invasive species may also be an ecological threat for native container-breeding mosquitoes which share a similar larval habitat. Therefore, it is of importance to gain knowledge on ecological and eco-toxicological features of the Asian bush mosquito. However, optimal laboratory feeding conditions have not yet been established. Standardized feeding methods will be needed in assessing the impact of insecticides or competitional strength of this species. To fill this gap, we performed experiments on food quality and quantity for Ae. j. japonicus larvae. We found out that the commercial fish food TetraMin (Tetra, Melle, Germany) in a dose of 10 mg per larva is the most suitable food tested. We also suggest a protocol with a feeding sequence of seven portions for all larval stages of this species. PMID:26452522

  4. Macroclimate determines the global range limit of Aedes aegypti.

    PubMed

    Capinha, César; Rocha, Jorge; Sousa, Carla A

    2014-09-01

    Aedes aegypti is the main vector of dengue and a number of other diseases worldwide. Because of the domestic nature of this mosquito, the relative importance of macroclimate in shaping its distribution has been a controversial issue. We have captured here the worldwide macroclimatic conditions occupied by A. aegypti in the last century. We assessed the ability of this information to predict the species' observed distribution using supra-continental spatially-uncorrelated data. We further projected the distribution of the colonized climates in the near future (2010-2039) under two climate-change scenarios. Our results indicate that the macroclimate is largely responsible for setting the maximum range limit of A. aegypti worldwide and that in the near future, relatively wide areas beyond this limit will receive macroclimates previously occupied by the species. By comparing our projections, with those from a previous model based strictly on species-climate relationships (i.e., excluding human influence), we also found support for the hypothesis that much of the species' range in temperate and subtropical regions is being sustained by artificial environments. Altogether, these findings suggest that, if the domestic environments commonly exploited by this species are available in the newly suitable areas, its distribution may expand considerably in the near future. PMID:24643859

  5. Oxime derivatives with larvicidal activity against Aedes aegypti L.

    PubMed

    Lima, Tamires Cardoso; Santos, Sandra Regina Lima; Uliana, Marciana P; Santos, Roseli La Corte; Brocksom, Timothy John; Cavalcanti, Sócrates Cabral de Holanda; de Sousa, Damião Pergentino

    2015-08-01

    Oximes containing secondary metabolites constitute an important group of bioactive compounds and have been described and frequently updated in the literature due to their pharmacological properties. Thus, the aim of this study was to evaluate the larvicidal activity of a series of fourteen structurally related [1,4]-Benzoquinone mono-oximes on third-instar Aedes aegypti larvae and to investigate structure-activity relationships (SAR) of these compounds. Results of larvicidal assay revealed that all oximes were found to have larvicidal activity. Compound 2,6-dimethyl-[1,4]-benzoquinone oxime tosylate (11) was the most bioactive (LC50 = 9.858 ppm), followed by 2-methyl-[1,4]-benzoquinone oxime tosylate (9) (LC50 = 14.450 ppm). [1,4]-benzoquinone oxime (1) exhibited the lowest potency, with an LC50 = 121.181 ppm. The molecular characteristics which may help to understand the assayed compounds larvicidal activity were identified. SAR indicates that the addition of alkyl groups attached to the ring, number, position in the unsaturated cyclic structure, and size of these groups influence the larvicidal activity. Moreover, the lipophilicity seems to play an important role in increasing the larvicidal effect, because, in general, tosyl-containing products were more potent than products containing free OH. PMID:25956398

  6. Origin of the Dengue Fever Mosquito, Aedes aegypti, in California

    PubMed Central

    Gloria-Soria, Andrea; Brown, Julia E.; Kramer, Vicki; Hardstone Yoshimizu, Melissa; Powell, Jeffrey R.

    2014-01-01

    Dengue fever is among the most widespread vector-borne infectious diseases. The primary vector of dengue is the Aedes aegypti mosquito. Ae. aegypti is prevalent in the tropics and sub-tropics and is closely associated with human habitats outside its native range of Africa. While long established in the southeastern United States of America where dengue is re-emerging, breeding populations have never been reported from California until the summer of 2013. Using 12 highly variable microsatellite loci and a database of reference populations, we have determined that the likely source of the California introduction is the southeastern United States, ruling out introductions from abroad, from the geographically closer Arizona or northern Mexico populations, or an accidental release from a research laboratory. The power to identify the origin of new introductions of invasive vectors of human disease relies heavily on the availability of a panel of reference populations. Our work demonstrates the importance of generating extensive reference databases of genetically fingerprinted human-disease vector populations to aid public health efforts to prevent the introduction and spread of vector-borne diseases. PMID:25077804

  7. Formulas of components of citronella oil against mosquitoes (Aedes aegypti).

    PubMed

    Hsu, Wey-Shin; Yen, Jui-Hung; Wang, Yei-Shung

    2013-01-01

    The mosquito Aedes aegypti is an epidemic vector of several diseases such as dengue fever and yellow fever. Several pesticides are used to control the mosquito population. Because of their frequent use, some mosquitoes have developed resistance. In this study, we used the Y-tube olfactometer to test essential oils of Cymbopogon species and screened specific formulas of components as repellents against Ae. aegypti. At 400 μL, the extracted oil of citronella grass (Cymbopogon nardus) and myrcene produced a low-active response by inhibiting mosquito host-seeking activity. Citronella grass, lemon grass (Cymbopogon citratus), citral and myrcene also produced a low-treatment response to repellents, for more potential to affect host-seeking behavior. Furthermore, the mixture of citral, myrcene, and citronellal oil (C:M:Ci = 6:4:1) greatly affected and inhibited host-seeking behavior (76% active response; 26% treatment response with 40 μL; 42.5%, 18% with 400 μL; and 19%, 23% with 1000 μL). As compared with the result for N,N-diethyl-3-methylbenzamide (DEET; 44%, 22% with 400 μL), adjusting the composition formulas of citronella oil had a synergistic effect, for more effective repellent against Ae. aegypti. PMID:23998314

  8. Pyrethroid resistance in Aedes aegypti larvae (Diptera: Culicidae) from Singapore.

    PubMed

    Koou, Sin-Ying; Chong, Chee-Seng; Vythilingam, Indra; Ng, Lee-Ching; Lee, Chow-Yang

    2014-01-01

    We report the first comprehensive insecticide susceptibility status ofAedes aegypti (L.) larvae from Singapore. The study indicated that Ae. aegypti is susceptible to temephos, although resistance (RR50 = 1.29-4.43-fold) couldbe developing. Of high concern is the detection of moderate to high resistance to permethrin (RR50 = 29-47-fold) and etofenprox (RR50 = 14-34-fold). Biolarvicide Bacillus thuringiensis israelensis (Bti) remains effective. The insecticide susceptibility profile of Ae. aegypti larvae was found to be homogenous among the different sites studied across the island city. The addition of synergists piperonyl butoxide, S,S,S,-tributyl phosphorotrithioate, and triphenyl phosphate generally failed to enhance the toxicity of the insecticides investigated, suggesting an insignificant role of metabolic-based resistance, and a possible involvement of target site resistance. Further biochemical investigation of specific metabolic enzyme activities suggested that detoxifying enzymes, mono-oxygenases, esterases, glutathione S-transferases, and altered acetylcholinesterases, generally did not contribute to the resistance observed. This study clearly demonstrated that pyrethroid resistance is widespread among Ae. aegypti population and lowered susceptibility to organophosphates is developing. PMID:24605467

  9. Distribution and dynamics of Wolbachia infection in Malaysian Aedes albopictus.

    PubMed

    Joanne, Sylvia; Vythilingam, Indra; Yugavathy, Nava; Leong, Cherng-Shii; Wong, Meng-Li; AbuBakar, Sazaly

    2015-08-01

    Wolbachia are maternally transmitted bacteria found in most arthropods and nematodes, but little is known about their distribution and reproductive dynamics in the Malaysian dengue vector Aedes albopictus. In this study, polymerase chain reaction (PCR) was used to determine the presence of Wolbachia from field collected Ae. albopictus from various parts of the country using wsp specific primers. Ae. albopictus had Wolbachia infection ranging from 60 to 100%. No sequence diversity of wsp gene was found within all wAlbA and wAlbB sequences. Our findings suggest that Wolbachia infection amongst the Malaysian Ae. albopictus were not homogenously distributed in all districts in Malaysia. The presence of Wolbachia in different organs of Ae. albopictus was also determined. Wolbachia were only found in the ovaries and midguts of the mosquitoes, while absent in the salivary glands. The effects of Wolbachia on Ae. albopictus fecundity, longevity and egg viability were studied using infected and uninfected colonies. The removal of Wolbachia from Ae. albopictus resulted in reduced fecundity, longevity and egg viability, thus. Wolbachia seem to play a vital role in Ae. albopictus reproductive system. PMID:25899523

  10. New Candidates for Plant-Based Repellents Against Aedes aegypti.

    PubMed

    Misni, Norashiqin; Nor, Zurainee Mohamed; Ahmad, Rohani

    2016-06-01

    Based on an ethnobotanical study on use for plant species against mosquito bites in the Kota Tinggi District, Johor State, Malaysia, 3 plants selected for study, Citrus aurantifolia (leaves), Citrus grandis (fruit peel), and Alpinia galanga (rhizome), were extracted using hydrodistillation to produce essential oils. These essential oils were then formulated as a lotion using a microencapsulation process and then tested for their repellent effect against Aedes aegypti. N,N-diethyl-m-toluamide (deet) was also prepared in the same formulation and tested for repellency as controls. Four commercial plant-based repellent (KAPS(®), MozAway(®), BioZ Natural(®), and Mosiquard(®)) also were incorporated in the bioassay for comparison purposes. Bioassays revealed that at 20% concentration all repellent formulations demonstrated complete protection for 2 h and >90% for 4 h post-application. The A. galanga-based formulation provided the greatest level of protection (98.91%), which extended for 4 h post-application and was not significantly different from deet at similar concentration. When compared with commercial plant-based repellents (KAPS(®), MozAway(®), and BioZ Natural(®)), the 3 lotion formulations showed significantly better protection against Ae. aegypti bites, providing >90% protection for 4 h. In conclusion, our 3 plant-based lotion formulations provided acceptable levels of protection against host-seeking Ae. aegypti and should be developed. PMID:27280349

  11. Repellent activity of selected essential oils against Aedes aegypti.

    PubMed

    Choochote, W; Chaithong, U; Kamsuk, K; Jitpakdi, A; Tippawangkosol, P; Tuetun, B; Champakaew, D; Pitasawat, B

    2007-07-01

    Essential oils extracted from ten plant species were screened for repellency against Aedes aegypti mosquitoes. Three oils; Zanthoxylum piperitum, Anethum graveolens and Kaempferia galanga, exerted protection against A. aegypti, with median complete-protection times of 1, 0.5 and 0.25 h, respectively. The protection times were increased significantly by incorporating 10% vanillin. The highest potential was established from Z. piperitum oil +10% vanillin (2.5 h, range=1-2.5 h). Mixtures from pairs of the effective oils possessed slight repellency that ranged from 0-0.5 h. None of the oil combinations repelled A. aegypti for longer than their constituent oil alone. With vanillin added, however, each oil mixture provided improved protection, which was approximately equal to oil on its own. GC/MS analysis revealed that the main component of Z. piperitum fruit oil was limonene (37.99%), with minor amounts of sabinene (13.30%) and beta-myrcene (7.17%). Repellent testing of stored samples of Z. piperitum fruit oil against A. aegypti demonstrated that repellent activity of those kept at -20 degrees C or 4 degrees C was present for a period of at least 3 months. Therefore, the essential oil of Z. piperitum fruit may prove useful in the development of mosquito repellents as an effective personal protection measure against mosquito bites. PMID:17512681

  12. Dengue virus-infected Aedes aegypti in the home environment.

    PubMed

    Garcia-Rejon, Julian; Loroño-Pino, Maria Alba; Farfan-Ale, Jose Arturo; Flores-Flores, Luis; Del Pilar Rosado-Paredes, Elsy; Rivero-Cardenas, Nubia; Najera-Vazquez, Rosario; Gomez-Carro, Salvador; Lira-Zumbardo, Victor; Gonzalez-Martinez, Pedro; Lozano-Fuentes, Saul; Elizondo-Quiroga, Darwin; Beaty, Barry J; Eisen, Lars

    2008-12-01

    We determined abundance of Aedes aegypti mosquitoes and presence of dengue virus (DENV) in females collected from premises of laboratory-confirmed dengue patients over a 12-month period (March 2007 to February 2008) in Merida, Mexico. Backpack aspiration from 880 premises produced 1,836 females and 1,292 males indoors (predominantly from bedrooms) and 102 females and 108 males from patios/backyards. The mean weekly indoor catch rate per home peaked at 7.8 females in late August. Outdoor abundances of larvae or pupae were not predictive of female abundance inside the home. DENV-infected Ae. aegypti females were recovered from 34 premises. Collection of DENV-infected females from homes of dengue patients up to 27 days after the onset of symptoms (median, 14 days) shows the usefulness of indoor insecticide application in homes of suspected dengue patients to prevent their homes from becoming sources for dispersal of DENV by persons visiting and being bitten by infected mosquitoes. PMID:19052309

  13. The Aedes aegypti Toll Pathway Controls Dengue Virus Infection

    PubMed Central

    Xi, Zhiyong; Ramirez, Jose L.; Dimopoulos, George

    2008-01-01

    Aedes aegypti, the mosquito vector of dengue viruses, utilizes its innate immune system to ward off a variety of pathogens, some of which can cause disease in humans. To date, the features of insects' innate immune defenses against viruses have mainly been studied in the fruit fly Drosophila melanogaster, which appears to utilize different immune pathways against different types of viruses, in addition to an RNA interference–based defense system. We have used the recently released whole-genome sequence of the Ae. aegypti mosquito, in combination with high-throughput gene expression and RNA interference (RNAi)-based reverse genetic analyses, to characterize its response to dengue virus infection in different body compartments. We have further addressed the impact of the mosquito's endogenous microbial flora on virus infection. Our findings indicate a significant role for the Toll pathway in regulating resistance to dengue virus, as indicated by an infection-responsive regulation and functional assessment of several Toll pathway–associated genes. We have also shown that the mosquito's natural microbiota play a role in modulating the dengue virus infection, possibly through basal-level stimulation of the Toll immune pathway. PMID:18604274

  14. Dietary control of late trypsin gene transcription in Aedes aegypti.

    PubMed

    Noriega, F G; Barillas-Mury, C; Wells, M A

    1994-06-01

    In Aedes aegypti the levels of midgut trypsin activity after feeding are directly proportional to the protein concentration in the meal. The mechanisms of this up-regulatory event were investigated by analyzing the expression of the late trypsin gene under different dietary conditions. Transcription of the gene was dependent on both the quality and quantity of protein in the meal. As measured by Northern blot analysis, the levels of late trypsin gene expression increased up to 100-fold 24 h after feeding on gamma-globulin, hemoglobin or albumin (100 mg/ml). In contrast, gelatin, histone, amino acids, saline or agarose were very poor inducers of transcription. The rates of late trypsin transcription induced during the first 24 h were directly proportional to the concentration of protein in the meal. These data further support the suggestion that the primary mechanism that regulates the synthesis of trypsin in the mosquito midgut is transcriptional regulation of the gene. This regulatory mechanism enables the midgut to maintain the appropriate balance between protease synthesis and the protein content of the meal. PMID:7519098

  15. Standardized Laboratory Feeding of Larval Aedes japonicus japonicus (Diptera: Culicidae).

    PubMed

    Bock, Friederike; Kuch, Ulrich; Pfenninger, Markus; Müller, Ruth

    2015-01-01

    The Asian bush mosquito (Aedes japonicus japonicus, Theobald 1901) is an invasive culicid species which originates in Asia but is nowadays present in northern America and Europe. It is a competent vector for several human disease pathogens. In addition to the public health threat, this invasive species may also be an ecological threat for native container-breeding mosquitoes which share a similar larval habitat. Therefore, it is of importance to gain knowledge on ecological and eco-toxicological features of the Asian bush mosquito. However, optimal laboratory feeding conditions have not yet been established. Standardized feeding methods will be needed in assessing the impact of insecticides or competitional strength of this species. To fill this gap, we performed experiments on food quality and quantity for Ae. j. japonicus larvae. We found out that the commercial fish food TetraMin (Tetra, Melle, Germany) in a dose of 10 mg per larva is the most suitable food tested. We also suggest a protocol with a feeding sequence of seven portions for all larval stages of this species. PMID:26452522

  16. Gene flow networks among American Aedes aegypti populations

    PubMed Central

    Gonçalves da Silva, Anders; Cunha, Ivana C L; Santos, Walter S; Luz, Sérgio L B; Ribolla, Paulo E M; Abad-Franch, Fernando

    2012-01-01

    The mosquito Aedes aegypti, the dengue virus vector, has spread throughout the tropics in historical times. While this suggests man-mediated dispersal, estimating contemporary connectivity among populations has remained elusive. Here, we use a large mtDNA dataset and a Bayesian coalescent framework to test a set of hypotheses about gene flow among American Ae. aegypti populations. We assessed gene flow patterns at the continental and subregional (Amazon basin) scales. For the Americas, our data favor a stepping-stone model in which gene flow is higher among adjacent populations but in which, at the same time, North American and southeastern Brazilian populations are directly connected, likely via sea trade. Within Amazonia, the model with highest support suggests extensive gene flow among major cities; Manaus, located at the center of the subregional transport network, emerges as a potentially important connecting hub. Our results suggest substantial connectivity across Ae. aegypti populations in the Americas. As long-distance active dispersal has not been observed in this species, our data support man-mediated dispersal as a major determinant of the genetic structure of American Ae. aegypti populations. The inferred topology of interpopulation connectivity can inform network models of Ae. aegypti and dengue spread. PMID:23144654

  17. Origin of the dengue fever mosquito, Aedes aegypti, in California.

    PubMed

    Gloria-Soria, Andrea; Brown, Julia E; Kramer, Vicki; Hardstone Yoshimizu, Melissa; Powell, Jeffrey R

    2014-01-01

    Dengue fever is among the most widespread vector-borne infectious diseases. The primary vector of dengue is the Aedes aegypti mosquito. Ae. aegypti is prevalent in the tropics and sub-tropics and is closely associated with human habitats outside its native range of Africa. While long established in the southeastern United States of America where dengue is re-emerging, breeding populations have never been reported from California until the summer of 2013. Using 12 highly variable microsatellite loci and a database of reference populations, we have determined that the likely source of the California introduction is the southeastern United States, ruling out introductions from abroad, from the geographically closer Arizona or northern Mexico populations, or an accidental release from a research laboratory. The power to identify the origin of new introductions of invasive vectors of human disease relies heavily on the availability of a panel of reference populations. Our work demonstrates the importance of generating extensive reference databases of genetically fingerprinted human-disease vector populations to aid public health efforts to prevent the introduction and spread of vector-borne diseases. PMID:25077804

  18. Population Genetic Structure of Aedes fluviatilis (Diptera: Culicidae).

    PubMed

    Multini, Laura Cristina; Wilke, André Barretto Bruno; Suesdek, Lincoln; Marrelli, Mauro Toledo

    2016-01-01

    Although Aedes fluviatilis is an anthropophilic mosquito found abundantly in urban environments, its biology, epidemiological potential and genetic characteristics are poorly understood. Climate change and urbanization processes that result in environmental modifications benefit certain anthropophilic mosquito species such as Ae. fluviatilis, greatly increasing their abundance in urban areas. To gain a better understanding of whether urbanization processes modulate the genetic structure of this species in the city of São Paulo, we used eight microsatellite loci to genetically characterize Ae. fluviatilis populations collected in nine urban parks in the city of São Paulo. Our results show that there is high gene flow among the populations of this species, heterozygosity deficiency and low genetic structure and that the species may have undergone a recent population expansion. There are two main hypotheses to explain these findings: (i) Ae. fluviatilis populations have undergone a population expansion as a result of urbanization; and (ii) as urbanization of the city of São Paulo occurred recently and was quite intense, the structuring of these populations cannot be observed yet, apart from in the populations of Ibirapuera and Piqueri parks, where the first signs of structuring have appeared. We believe that the expansion found in Ae. fluviatilis populations is probably correlated with the unplanned urbanization of the city of São Paulo, which transformed green areas into urbanized areas, as well as the increasing population density in the city. PMID:27598889

  19. Experimental Transmission of Mayaro Virus by Aedes aegypti

    PubMed Central

    Long, Kanya C.; Ziegler, Sarah A.; Thangamani, Saravanan; Hausser, Nicole L.; Kochel, Tadeusz J.; Higgs, Stephen; Tesh, Robert B.

    2011-01-01

    Outbreaks of Mayaro fever have been associated with a sylvatic cycle of Mayaro virus (MAYV) transmission in South America. To evaluate the potential for a common urban mosquito to transmit MAYV, laboratory vector competence studies were performed with Aedes aegypti from Iquitos, Peru. Oral infection in Ae. aegypti ranged from 0% (0/31) to 84% (31/37), with blood meal virus titers between 3.4 log10 and 7.3 log10 plaque-forming units (PFU)/mL. Transmission of MAYV by 70% (21/30) of infected mosquitoes was shown by saliva collection and exposure to suckling mice. Amount of viral RNA in febrile humans, determined by real-time polymerase chain reaction, ranged from 2.7 to 5.3 log10 PFU equivalents/mL. Oral susceptibility of Ae. aegypti to MAYV at titers encountered in viremic humans may limit opportunities to initiate an urban cycle; however, transmission of MAYV by Ae. aegypti shows the vector competence of this species and suggests potential for urban transmission. PMID:21976583

  20. DIBROMOACETIC ACID, A PREVALENT BY-PRODUCT OF DRINKING WATER DISINFECTION, COMPROMISES THE SYNTHESIS OF SPECIFIC SEMINFEROUS TUBULE PROTEINS FOLLOWING BOTH IN VIVO AND IN VITRO EXPOSURES

    EPA Science Inventory

    ABSTRACT
    Dibromoacetic acid(DBA) is a byproduct of drinking water disinfection that alters spermatogenesis in adult male rats. To identify a mechanism by which DBA alters spermatogenesis, seminiferous tubules representing specific groups of spermatogenic stages were expos...

  1. Poor lysosomal membrane integrity in proximal tubule cells of haptoglobin 2-2 genotype mice with diabetes mellitus

    PubMed Central

    Asleh, Rabea; Nakhoul, Farid M.; Miller-Lotan, Rachel; Awad, Hoda; Farbstein, Dan; Levy, Nina S.; Nakhoul, Nakhoul; Iancu, Theodore C.; Manov, Irena; Laue, Michael; Traber, Maret G.; Lebold, Katie M.; Levy, Andrew P.

    2013-01-01

    The haptoglobin (Hp) genotype is a major determinant of progression of nephropathy in individuals with diabetes mellitus (DM). The major function of the Hp protein is to bind and modulate the fate of extracorpuscular hemoglobin and its iron cargo. We have previously demonstrated an interaction between the Hp genotype and the DM on the accumulation of iron in renal proximal tubule cells. The primary objective of this study was to determine the intracellular localization of this iron in the proximal tubule cell and to assess its potential toxicity. Transmission electron microscopy demonstrated a marked accumulation of electron-dense deposits in the lysosomes of proximal tubules cells in Hp 2-2 DM mice. Energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy were used to perform elemental analysis of these deposits and demonstrated that these deposits were iron rich. These deposits were associated with lysosomal membrane lipid peroxidation and loss of lysosomal membrane integrity. Vitamin E administration to Hp 2-2 DM mice resulted in a significant decrease in both intralysosomal iron-induced oxidation and lysosomal destabilization. Iron-induced renal tubular injury may play a major role in the development of diabetic nephropathy and may be a target for slowing the progression of renal disease. PMID:22749805

  2. Fabrication of Collagen Gel Hollow Fibers by Covalent Cross-Linking for Construction of Bioengineering Renal Tubules.

    PubMed

    Shen, Chong; Zhang, Guoliang; Wang, Qichen; Meng, Qin

    2015-09-01

    Collagen, the most used natural biomacromolecule, has been extensively utilized to make scaffolds for cell cultures in tissue engineering, but has never been fabricated into the configuration of a hollow fiber (HF) for cell culture due to its poor mechanical properties. In this study, renal tubular cell-laden collagen hollow fiber (Col HF) was fabricated by dissolving sacrificial Ca-alginate cores from collagen shells strengthened by carbodiimide cross-linking. The inner/outer diameters of the Col HF were precisely controlled by the flow rates of core alginate/shell collagen solution in the microfluidic device. As found, the renal tubular cells self-assembled into renal tubules with diameters of 50-200 μm post to the culture in Col HF for 10 days. According to the 3D reconstructed confocal images or HE staining, the renal cells appeared as a tight tubular monolayer on the Col HF inner surface, sustaining more 3D cell morphology than the cell layer on the 2D flat collagen gel surface. Moreover, compared with the cultures in either a Transwell or polymer HF membrane, the renal tubules in Col HF exhibited at least 1-fold higher activity on brush border enzymes of alkaline phosphatase and γ-glutamyltransferase, consistent with their gene expressions. The enhancement occurred similarly on multidrug resistance protein 2 and glucose uptake. Such bioengineered renal tubules in Col HF will present great potential as alternatives to synthetic HF in both clinical use and pharmaceutical investigation. PMID:26280545

  3. Association of malachite green-positive material with heparan sulfate proteoglycan double tracks in basement membrane of mouse kidney tubules.

    PubMed

    Inoue, S

    1995-03-01

    The presence of lipids in the basement membrane of the mouse kidney tubules was examined by histochemical staining with malachite green. Pieces of mouse kidney cortex were immersed in a fixative containing 3% glutaraldehyde and 0.1% malachite green in 0.067 M sodium cacodylate buffer, pH 6.8, for 18 hr at 4 degrees C. Control tissue was fixed in the same way except that no malachite green was added to the fixative. The tissue pieces were cryoprotected, frozen in Freon 22, and subjected to freeze-substitution in dry acetone containing 1% OsO4. Thin sections of Epon-embedded specimens were observed by electron microscopy at first without uranyl-lead counterstaining. The basement membrane of mouse kidney tubules was positively stained in a pattern composed of an irregular assembly of 5-8-nm wide strands. The nature of these malachite green-positive strands was further examined by counterstaining thin sections with uranyl-lead, and they were identified as 4.5-5-nm wide ribbon-like "double tracks" previously characterized as the form taken by heparan sulfate proteoglycan in basement membranes. It is concluded that lipids are present in the basement membrane of mouse kidney tubules in association with heparan sulfate proteoglycan. PMID:7868858

  4. Identification of domains of the Tomato spotted wilt virus NSm protein involved in tubule formation, movement and symptomatology.

    PubMed

    Li, Weimin; Lewandowski, Dennis J; Hilf, Mark E; Adkins, Scott

    2009-07-20

    Deletion and alanine-substitution mutants of the Tomato spotted wilt virus NSm protein were generated to identify domains involved in tubule formation, movement and symptomatology using a heterologous Tobacco mosaic virus expression system. Two regions of NSm, G(19)-S(159) and G(209)-V(283), were required for both tubule formation in protoplasts and cell-to-cell movement in plants, indicating a correlation between these activities. Three amino acid groups, D(154), EYKK(205-208) and EEEEE(284-288) were linked with long-distance movement in Nicotiana benthamiana. EEEEE(284-288) was essential for NSm-mediated long-distance movement, whereas D(154) was essential for tubule formation and cell-to-cell movement; indicating separate genetic controls for cell-to-cell and long-distance movement. The region I(57)-N(100) was identified as the determinant of foliar necrosis in Nicotiana benthamiana, and mutagenesis of HH(93-94) greatly reduced necrosis. These findings are likely applicable to other tospovirus species, especially those within the 'New World' group as NSm sequences are highly conserved. PMID:19481775

  5. Syp1 is a conserved endocytic adaptor that contains domains involved in cargo selection and membrane tubulation

    SciTech Connect

    Reider, Amanda; Barker, Sarah L.; Mishra, Sanjay K.; Im, Young Jun; Maldonado-Báez, Lymarie; Hurley, James H.; Traub, Linton M.; Wendland, Beverly

    2010-10-28

    Internalization of diverse transmembrane cargos from the plasma membrane requires a similarly diverse array of specialized adaptors, yet only a few adaptors have been characterized. We report the identification of the muniscin family of endocytic adaptors that is conserved from yeast to human beings. Solving the structures of yeast muniscin domains confirmed the unique combination of an N-terminal domain homologous to the crescent-shaped membrane-tubulating EFC/F-BAR domains and a C-terminal domain homologous to cargo-binding {mu} homology domains ({mu}HDs). In vitro and in vivo assays confirmed membrane-tubulation activity for muniscin EFC/F-BAR domains. The {mu}HD domain has conserved interactions with the endocytic adaptor/scaffold Ede1/eps15, which influences muniscin localization. The transmembrane protein Mid2, earlier implicated in polarized Rho1 signalling, was identified as a cargo of the yeast adaptor protein. These and other data suggest a model in which the muniscins provide a combined adaptor/membrane-tubulation activity that is important for regulating endocytosis.

  6. Assessment of 24-hours Aldosterone Administration on Protein Abundances in Fluorescence-Sorted Mouse Distal Renal Tubules by Mass Spectrometry

    PubMed Central

    Jensen, Thomas B; Pisitkun, Trairak; Hoffert, Jason D; Jensen, Uffe B; Fenton, Robert A; Praetorius, Helle A; Knepper, Mark A; Praetorius, Jeppe

    2013-01-01

    Background/Aims Aldosterone exerts multiple long-term effects in the distal renal tubules. The aim of this study was to establish a method for identifying proteins in these tubules that change in abundance by only 24-hours aldosterone administration. Methods Mice endogenously expressing green fluorescent protein (eGFP) in the connecting tubule and cortical collecting ducts were treated with a subcutaneous injection of 2.0 mg/kg aldosterone or vehicle (n=5), and sacrificed 24 hours later. Suspensions of single cells were obtained enzymatically, and eGFP positive cells were isolated by fluorescence activated cell sorting (FACS). Samples of 100 μg proteins were digested with trypsin and labeled with 8-plex iTRAQ reagents and processed for liquid chromatography tandem mass spectrometry (LC-MS/MS). Results FACS yielded 1.4 million cells per mouse. The LC-MS/MS spectra were matched to peptides by the SEQUEST search algorithm, which identified 3002 peptides corresponding to 506 unique proteins of which 20 significantly changed abundance 24-hours after aldosterone injection. Conclusion We find the method suitable and useful for studying hormonal effects on protein abundance in distal tubular segments. PMID:23428628

  7. SEC-10 and RAB-10 coordinate basolateral recycling of clathrin-independent cargo through endosomal tubules in Caenorhabditis elegans

    PubMed Central

    Chen, Sanyou; Li, Lei; Li, Jiangli; Liu, Bei; Zhu, Xinyu; Zheng, Li; Zhang, Rongying; Xu, Tao

    2014-01-01

    Despite the increasing number of regulatory proteins identified in clathrin-independent endocytic (CIE) pathways, our understanding of the exact functions of these proteins and the sequential manner in which they function remains limited. In this study, using the Caenorhabditis elegans intestine as a model, we observed a unique structure of interconnected endosomal tubules, which is required for the basolateral recycling of several CIE cargoes including hTAC, GLUT1, and DAF-4. SEC-10 is a subunit of the octameric protein complex exocyst. Depleting SEC-10 and several other exocyst components disrupted the endosomal tubules into various ring-like structures. An epistasis analysis further suggested that SEC-10 operates at the intermediate step between early endosomes and recycling endosomes. The endosomal tubules were also sensitive to inactivation of the Rab GTPase RAB-10 and disruption of microtubules. Taken together, our data suggest that SEC-10 coordinates with RAB-10 and microtubules to form the endosomal tubular network for efficient recycling of particular CIE cargoes. PMID:25301900

  8. Uranyl nitrate inhibits lactate gluconeogenesis in isolated human and mouse renal proximal tubules: A {sup 13}C-NMR study

    SciTech Connect

    Renault, Sophie; Faiz, Hassan; Gadet, Rudy; Ferrier, Bernard; Martin, Guy; Baverel, Gabriel; Conjard-Duplany, Agnes

    2010-01-01

    As part of a study on uranium nephrotoxicity, we investigated the effect of uranyl nitrate in isolated human and mouse kidney cortex tubules metabolizing the physiological substrate lactate. In the millimolar range, uranyl nitrate reduced lactate removal and gluconeogenesis and the cellular ATP level in a dose-dependent fashion. After incubation in phosphate-free Krebs-Henseleit medium with 5 mM L-[1-{sup 13}C]-, or L-[2-{sup 13}C]-, or L-[3-{sup 13}C]lactate, substrate utilization and product formation were measured by enzymatic and NMR spectroscopic methods. In the presence of 3 mM uranyl nitrate, glucose production and the intracellular ATP content were significantly reduced in both human and mouse tubules. Combination of enzymatic and NMR measurements with a mathematical model of lactate metabolism revealed an inhibition of fluxes through lactate dehydrogenase and the gluconeogenic enzymes in the presence of 3 mM uranyl nitrate; in human and mouse tubules, fluxes were lowered by 20% and 14% (lactate dehydrogenase), 27% and 32% (pyruvate carboxylase), 35% and 36% (phosphoenolpyruvate carboxykinase), and 39% and 45% (glucose-6-phosphatase), respectively. These results indicate that natural uranium is an inhibitor of renal lactate gluconeogenesis in both humans and mice.

  9. SPONTANEOUS OCCURRENCE OF A DISTINCTIVE RENAL TUBULE TUMOR PHENOTYPE IN RAT CARCINOGENICITY STUDIES CONDUCTED BY THE NATIONAL TOXICOLOGY PROGRAM (NTP)

    PubMed Central

    Hard, Gordon C; Seely, John Curtis; Kissling, Grace E; Betz, Laura J

    2010-01-01

    The Toxicology Data Management System (TDMS) of the National Toxicology Program, NIEHS, NIH, was surveyed for occurrence and distribution of a distinctive renal tubule tumor type in rats. The hallmark features of this tumor included eosinophilic/amphophilic staining, large finely granular cells, and numerous vacuoles and/or minilumens. It is referred to here as the amphophilic-vacuolar (AV) variant of renal tubule tumor. Of 154 studies in which renal tubule tumors had been recorded in the standard single sections of kidney in the TDMS, there were collectively 1012 rats with renal adenomas, carcinomas or adenocarcinomas, and of these, 100 displayed the distinctive AV morphology, representing 74 studies involving mostly the F344 rat, but also the Sprague-Dawley and Wistar strains. The AV tumors (mainly adenomas but also some carcinomas) occurred usually as solitary lesions in the affected animals. However, they were multiple and bilateral in a few cases. They were equally distributed between the sexes, did not metastasize (at least to the lung), and were not associated with chronic progressive nephropathy. The distribution of this renal tumor type was random across studies and dose groups, underscoring the likelihood that it was of spontaneous origin and not chemically induced. Accordingly, it is suggested that this distinctive renal tumor phenotype be recorded as a separate category from conventional RTT when assessing the carcinogenic potential of a test compound. PMID:18441261

  10. Uric Acid Promotes Apoptosis in Human Proximal Tubule Cells by Oxidative Stress and the Activation of NADPH Oxidase NOX 4

    PubMed Central

    Verzola, Daniela; Ratto, Elena; Villaggio, Barbara; Parodi, Emanuele Luigi; Pontremoli, Roberto; Garibotto, Giacomo; Viazzi, Francesca

    2014-01-01

    Mild hyperuricemia has been linked to the development and progression of tubulointerstitial renal damage. However the mechanisms by which uric acid may cause these effects are poorly explored. We investigated the effect of uric acid on apoptosis and the underlying mechanisms in a human proximal tubule cell line (HK-2). Increased uric acid concentration decreased tubule cell viability and increased apoptotic cells in a dose dependent manner (up to a 7-fold increase, p<0.0001). Uric acid up-regulated Bax (+60% with respect to Ctrl; p<0.05) and down regulated X-linked inhibitor of apoptosis protein. Apoptosis was blunted by Caspase-9 but not Caspase-8 inhibition. Uric acid induced changes in the mitochondrial membrane, elevations in reactive oxygen species and a pronounced up-regulation of NOX 4 mRNA and protein (p<0.05). In addition, both reactive oxygen species production and apoptosis was prevented by the NADPH oxidase inhibitor DPI as well as by Nox 4 knockdown. URAT 1 transport inhibition by probenecid and losartan and its knock down by specific siRNA, blunted apoptosis, suggesting a URAT 1 dependent cell death. In summary, our data show that uric acid increases the permissiveness of proximal tubule kidney cells to apoptosis by triggering a pathway involving NADPH oxidase signalling and URAT 1 transport. These results might explain the chronic tubulointerstitial damage observed in hyperuricaemic states and suggest that uric acid transport in tubular cells is necessary for urate-induced effects. PMID:25514209

  11. Specificity of motor axon regeneration: a comparison of recovery following biodegradable conduit small gap tubulization and epineurial neurorrhaphy

    PubMed Central

    Yu, Youlai; Zhang, Peixun; Yin, Xiaofeng; Han, Na; Kou, Yuhui; Jiang, Baoguo

    2015-01-01

    Functional recovery is often unsatisfactory after lesions in the peripheral nervous system despite the strong potential for regeneration and advances in microsurgical techniques. Axonal regeneration in mixed nerve into inappropriate pathways is a major contributing factor to this failure. In this study, the rat femoral nerve model of transection and surgical repair was used to evaluate the specificity of motor axon regeneration as well as functional and morphological recovery using biodegradable conduit small gap tubulization compared to epineurial neurorrhaphy. 12 weeks after nerve repair, the specificity was assessed using the retrograde neurotracers TB and DiI to backlabel motor neurons that regenerate axons into muscle and cutaneous pathways. To evaluate the functional recovery of the quadriceps muscle, the quadriceps muscle forces were examined. The quadriceps muscle and myelinated axons were assessed using electrophysiology and histology. The results showed that the specificity of motor axon regeneration (preferential reinnervation) was significantly higher when the nerve transection was treated by biodegradable conduit small gap tubulization and there was no significant difference between the two suture methods with respect to the functional and morphological recovery. This study demonstrated that the quicker and easier biodegradable conduit small gap tubulization may get more accurate reinnervation than traditional epineurial neurorrhaphy and produced functional and morphological recovery equal to traditional epineurial neurorrhaphy. PMID:25755828

  12. Prior Hydrologic Disturbance Affects Competition between Aedes Mosquitoes via Changes in Leaf Litter

    PubMed Central

    Smith, Cassandra D.; Freed, T. Zachary; Leisnham, Paul T.

    2015-01-01

    Allochthonous leaf litter is often the main resource base for invertebrate communities in ephemeral water-filled containers, and detritus quality can be affected by hydrologic conditions. The invasive mosquito Aedes albopictus utilizes container habitats for its development where it competes as larvae for detritus and associated microorganisms with the native Aedes triseriatus. Different hydrologic conditions that containers are exposed to prior to mosquito utilization affect litter decay and associated water quality. We tested the hypothesis that larval competition between A. albopictus and A. triseriatus would be differentially affected by prior hydrologic conditions. Experimental microcosms provisioned with Quercus alba L. litter were subjected to one of three different hydrologic treatments prior to the addition of water and mosquito larvae: dry, flooded, and a wet/dry cycle. Interspecific competition between A. albopictus and A. triseriatus was mediated by hydrologic treatment, and was strongest in the dry treatment vs. the flooded or wet/dry treatments. Aedes triseriatus estimated rate of population change (λ') was lowest in the dry treatment. Aedes albopictus λ' was unaffected by hydrologic treatment, and was on average always increasing (i.e., > 1). Aedes triseriatus λ' was affected by the interaction of hydrologic treatment with interspecific competition, and was on average declining (i.e., < 1.0), at the highest interspecific densities in the dry treatment. Dry treatment litter had the slowest decay rate and leached the highest concentration of tannin-lignin, but supported more total bacteria than the other treatments. These results suggest that dry conditions negatively impact A. triseriatus population performance and may result in the competitive exclusion of A. triseriatus by A. albopictus, possibly by reducing microbial taxa that Aedes species browse. Changing rainfall patterns with climate change are likely to affect competition between A

  13. Prior Hydrologic Disturbance Affects Competition between Aedes Mosquitoes via Changes in Leaf Litter.

    PubMed

    Smith, Cassandra D; Freed, T Zachary; Leisnham, Paul T

    2015-01-01

    Allochthonous leaf litter is often the main resource base for invertebrate communities in ephemeral water-filled containers, and detritus quality can be affected by hydrologic conditions. The invasive mosquito Aedes albopictus utilizes container habitats for its development where it competes as larvae for detritus and associated microorganisms with the native Aedes triseriatus. Different hydrologic conditions that containers are exposed to prior to mosquito utilization affect litter decay and associated water quality. We tested the hypothesis that larval competition between A. albopictus and A. triseriatus would be differentially affected by prior hydrologic conditions. Experimental microcosms provisioned with Quercus alba L. litter were subjected to one of three different hydrologic treatments prior to the addition of water and mosquito larvae: dry, flooded, and a wet/dry cycle. Interspecific competition between A. albopictus and A. triseriatus was mediated by hydrologic treatment, and was strongest in the dry treatment vs. the flooded or wet/dry treatments. Aedes triseriatus estimated rate of population change (λ') was lowest in the dry treatment. Aedes albopictus λ' was unaffected by hydrologic treatment, and was on average always increasing (i.e., > 1). Aedes triseriatus λ' was affected by the interaction of hydrologic treatment with interspecific competition, and was on average declining (i.e., < 1.0), at the highest interspecific densities in the dry treatment. Dry treatment litter had the slowest decay rate and leached the highest concentration of tannin-lignin, but supported more total bacteria than the other treatments. These results suggest that dry conditions negatively impact A. triseriatus population performance and may result in the competitive exclusion of A. triseriatus by A. albopictus, possibly by reducing microbial taxa that Aedes species browse. Changing rainfall patterns with climate change are likely to affect competition between A

  14. Hazard evaluation of chemicals that cause accumulation of alpha 2u-globulin, hyaline droplet nephropathy, and tubule neoplasia in the kidneys of male rats.

    PubMed Central

    Hard, G C; Rodgers, I S; Baetcke, K P; Richards, W L; McGaughy, R E; Valcovic, L R

    1993-01-01

    This review paper examines the relationship between chemicals inducing excessive accumulation of alpha 2u-globulin (alpha 2u-g) (CIGA) in hyaline droplets in male rat kidneys and the subsequent development of nephrotoxicity and renal tubule neoplasia in the male rat. This dose-responsive hyaline droplet accumulation distinguishes CIGA carcinogens from classical renal carcinogens. CIGA carcinogens also do not appear to react with DNA and are generally negative in short-term tests for genotoxicity, CIGA or their metabolites bind specifically, but reversibly, to male rat alpha 2u-g. The resulting complex appears to be more resistant to hydrolytic degradation in the proximal tubule than native, unbound alpha 2u-g. Single cell necrosis of the tubule epithelium, with associated granular cast formation and papillary mineralization, is followed by sustained regenerative tubule cell proliferation, foci of tubule hyperplasia in the convoluted proximal tubules, and renal tubule tumors. Although structurally similar proteins have been detected in other species, including humans, renal lesions characteristic of alpha 2u-g nephropathy have not been observed. Epidemiologic investigation has not specifically examined the CIGA hypothesis for humans. Based on cancer bioassays, hormone manipulation studies, investigations in an alpha 2u-g-deficient strain of rat, and other laboratory data, an increased proliferative response caused by chemically induced cytotoxicity appears to play a role in the development of renal tubule tumors in male rats. Thus, it is reasonable to suggest that the renal effects induced in male rats by chemicals causing alpha 2u-g accumulation are unlikely to occur in humans. Images FIGURE 1. FIGURE 2. FIGURE 3. FIGURE 4. FIGURE 5. FIGURE 6. FIGURE 7. FIGURE 8. FIGURE 9. FIGURE 10. FIGURE 11. FIGURE 12. FIGURE 13. PMID:7686485

  15. Introduction and Establishment of Aedes albopictus (Diptera: Culicidae) in Managua, Nicaragua.

    PubMed

    Belli, Alejandro; Arostegui, Jorge; Garcia, Jorge; Aguilar, Carlos; Lugo, Emperatriz; Lopez, Damaris; Valle, Sonia; Lopez, Mercedes; Harris, Eva; Coloma, Josefina

    2015-07-01

    Aedes aegypti (L.) is the main vector of dengue virus and more recently chikungunya virus in Latin America. However, the Asian tiger mosquito Aedes albopictus (Skuse, 1894) is expanding its global range and increasing its role in transmission of these diseases. In this report, we suggest that Ae. albopictus was introduced to the Department of Managua, Nicaragua, in 2010 via two independent routes and demonstrate its dissemination and establishment in urban neighborhoods by 2012. The coexistence of two competent vector species could alter the epidemiology of dengue and chikungunya as well as indicate the need for new strategies aimed at vector control. PMID:26335479

  16. Introduction and Establishment of Aedes albopictus (Diptera: Culicidae) in Managua, Nicaragua

    PubMed Central

    Belli, Alejandro; Arostegui, Jorge; Garcia, Jorge; Aguilar, Carlos; Lugo, Emperatriz; Lopez, Damaris; Valle, Sonia; Lopez, Mercedes; Harris, Eva; Coloma, Josefina

    2015-01-01

    Aedes aegypti (L.) is the main vector of dengue virus and more recently chikungunya virus in Latin America. However, the Asian tiger mosquito Aedes albopictus (Skuse, 1894) is expanding its global range and increasing its role in transmission of these diseases. In this report, we suggest that Ae. albopictus was introduced to the Department of Managua, Nicaragua, in 2010 via two independent routes and demonstrate its dissemination and establishment in urban neighborhoods by 2012. The coexistence of two competent vector species could alter the epidemiology of dengue and chikungunya as well as indicate the need for new strategies aimed at vector control. PMID:26335479

  17. [Occurrence of Aedes albopictus in the state of Pará, Brazil].

    PubMed

    Segura, Maria de Nazaré de Oliveira; Monteiro, Hamilton Antonio de Oliveira; Lopes, Ernani da Silva; da Silva, Orlando Vaz; Castro, Francisco Corrêa; Vasconcelos, Pedro Fernando da Costa

    2003-06-01

    It is first reported the detection of Aedes (Stg) albopictus mosquitoes in state of Par , Brazil, in the urban area of Medicil ndia, a municipality far 90 km from Altamira, where 42 adult mosquitoes were baited using human attraction. All mosquitoes were pooled and inoculated into C6/36 and suckling mice in attempts for virus isolation. No virus was isolated. The occurrence of Aedes albopictus in urban areas of the Amazon region is of concern since dengue and yellow fever viruses are endemic in the Amazon and thus there is a potential risk for this mosquito species to become infected with both viruses. PMID:12792693

  18. RME-8 coordinates the activity of the WASH complex with the function of the retromer SNX dimer to control endosomal tubulation

    PubMed Central

    Freeman, Caroline L.; Hesketh, Geoffrey; Seaman, Matthew N. J.

    2014-01-01

    ABSTRACT Retromer is a vital element of the endosomal protein sorting machinery and comprises two subcomplexes that operate together to sort membrane proteins (cargo) and tubulate membranes. Tubules are formed by a dimer of sorting nexins, a key component of which is SNX1. Cargo selection is mediated by the VPS35–VPS29–VPS26 trimer, which additionally recruits the WASH complex through VPS35 binding to the WASH complex subunit FAM21. Loss of function of the WASH complex leads to dysregulation of endosome tubulation, although it is unclear how this occurs. Here, we show that FAM21 also binds to the SNX1-interacting DNAJ protein RME-8. Loss of RME-8 causes altered kinetics of SNX1 membrane association and a pronounced increase in highly branched endosomal tubules. Building on previous observations from other laboratories, we show that these tubules contain membrane proteins that are dependent upon WASH complex activity for their localization to the plasma membrane. Therefore, we propose that the interaction between RME-8 and the WASH complex provides a means to coordinate the activity of the WASH complex with the membrane-tubulating function of the sorting nexins at sites where retromer-mediated endosomal protein sorting occurs. PMID:24643499

  19. Comparison of Vector Competence of Aedes mediovittatus and Aedes aegypti for Dengue Virus: Implications for Dengue Control in the Caribbean

    PubMed Central

    Poole-Smith, B. Katherine; Hemme, Ryan R.; Delorey, Mark; Felix, Gilberto; Gonzalez, Andrea L.; Amador, Manuel; Hunsperger, Elizabeth A.; Barrera, Roberto

    2015-01-01

    Background Aedes mediovittatus mosquitoes are found throughout the Greater Antilles in the Caribbean and often share the same larval habitats with Ae. Aegypti, the primary vector for dengue virus (DENV). Implementation of vector control measures to control dengue that specifically target Ae. Aegypti may not control DENV transmission in Puerto Rico (PR). Even if Ae. Aegypti is eliminated or DENV refractory mosquitoes are released, DENV transmission may not cease when other competent mosquito species like Ae. Mediovittatus are present. To compare vector competence of Ae. Mediovittatus and Ae. Aegypti mosquitoes, we studied relative infection and transmission rates for all four DENV serotypes. Methods To compare the vector competence of Ae. Mediovittatus and Ae. Aegypti, mosquitoes were exposed to DENV 1–4 per os at viral titers of 5–6 logs plaque-forming unit (pfu) equivalents. At 14 days post infectious bloodmeal, viral RNA was extracted and tested by qRT-PCR to determine infection and transmission rates. Infection and transmission rates were analyzed with a generalized line