scholarly journals Comparison of in vitro replication features of H7N3 influenza viruses from wild ducks and turkeys: potential implications for interspecies transmission

2006 ◽  
Vol 87 (1) ◽  
pp. 171-175 ◽  
Author(s):  
Simone Giannecchini ◽  
Laura Campitelli ◽  
Laura Calzoletti ◽  
Maria Alessandra De Marco ◽  
Alberta Azzi ◽  
...  

In previous work, it was shown that turkey H7N3 influenza viruses, presumably derived ‘in toto’ from interspecies transmission of duck viruses in Northern Italy, had only 2 aa differences in haemagglutinin and a few amino acid differences as well as a 23 aa deletion in neuraminidase compared with duck viruses. Here, the replication of these duck and turkey viruses in Madin–Darby canine kidney cells was investigated with respect to virus–cell fusion and viral elution from red blood cells. Duck viruses showed similar receptor-binding properties to turkey viruses but possessed a higher pH of fusion activation than the turkey viruses. Conversely, turkey viruses were not able to elute from red blood cells. These data confirm that neuraminidase-stalk deletion impairs the release of virions from cells and also confirm existence of naturally occurring viruses with different pH fusion activities, raising the possibility that these features may play a role in the evolution of influenza viruses in different hosts.

2012 ◽  
Vol 93 (8) ◽  
pp. 1645-1648 ◽  
Author(s):  
R. Bodewes ◽  
N. J. Nieuwkoop ◽  
R. J. Verburgh ◽  
R. A. M. Fouchier ◽  
A. D. M. E. Osterhaus ◽  
...  

Exchange of gene segments between mammalian and avian influenza A viruses may lead to the emergence of potential pandemic influenza viruses. Since co-infection of single cells with two viruses is a prerequisite for reassortment to take place, we assessed frequencies of double-infection in vitro using influenza A/H5N1 and A/H1N1 viruses expressing the reporter genes eGFP or mCherry. Double-infected A549 and Madin–Darby canine kidney cells were detected by confocal microscopy and flow cytometry.


2019 ◽  
Vol 317 (1) ◽  
pp. F30-F42
Author(s):  
Te-Jung Lu ◽  
Wei-Chih Kan ◽  
Sung-Sen Yang ◽  
Si-Tse Jiang ◽  
Sheng-Nan Wu ◽  
...  

Liddle syndrome is an inherited form of human hypertension caused by increasing epithelial Na+ channel (ENaC) expression. Increased Na+ retention through ENaC with subsequent volume expansion causes hypertension. In addition to ENaC, the Na+-K+-Cl− cotransporter (NKCC) and Na+-Cl− symporter (NCC) are responsible for Na+ reabsorption in the kidneys. Several Na+ transporters are evolutionarily regulated by the Ste20 kinase family. Ste20-related proline/alanine-rich kinase and oxidative stress-responsive kinase-1 phosphorylate downstream NKCC2 and NCC to maintain Na+ and blood pressure (BP) homeostasis. Mammalian Ste20 kinase 3 (MST3) is another member of the Ste20 family. We previously reported that reduced MST3 levels were found in the kidneys in spontaneously hypertensive rats and that MST3 was involved in Na+ regulation. To determine whether MST3 is involved in BP stability through Na+ regulation, we generated a MST3 hypomorphic mutation and designated MST3+/− and MST3−/− mice to examine BP and serum Na+ and K+ concentrations. MST3−/− mice exhibited hypernatremia, hypokalemia, and hypertension. The increased ENaC in the kidney played roles in hypernatremia. The reabsorption of more Na+ promoted more K+ secretion in the kidney and caused hypokalemia. The hypernatremia and hypokalemia in MST3−/− mice were significantly reversed by the ENaC inhibitor amiloride, indicating that MST3−/− mice reabsorbed more Na+ through ENaC. Furthermore, Madin-Darby canine kidney cells stably expressing kinase-dead MST3 displayed elevated ENaC currents. Both the in vivo and in vitro results indicated that MST3 maintained Na+ homeostasis through ENaC regulation. We are the first to report that MST3 maintains BP stability through ENaC regulation.


1987 ◽  
Vol 7 (4) ◽  
pp. 1326-1337
Author(s):  
S L Warren ◽  
W J Nelson

Madin-Darby canine kidney (MDCK) cells form polarized, multicellular epithelial structures in vitro. Low-level expression of pp60v-src in MDCK cells elicits plasticity in these multicellular structures. Plasticity was revealed by the displacement of cells from mechanically stressed regions of the epithelial monolayers; however, the two-dimensional relationship between the cells in the remainder of the monolayer was maintained. Electron microscopy of multicellular structures revealed abnormal separation of the lateral membranes of adjacent cells and selective uncoupling of the junctional complex; the zonula adherens was disrupted, but the zonula occludens and desmosomes were retained. Significantly, this result was not accompanied by transformation of the cells, as judged by the absence of anchorage-independent growth potential. These results demonstrate a nonmitogenic biological activity of pp60v-src which is experimentally dissociable from transformation. This morphoregulatory action on higher-order epithelial structures may reflect a function of related cellular tyrosine kinases.


2020 ◽  
Vol 14 (5) ◽  
pp. 616-623
Author(s):  
Yun-Feng Liu ◽  
Yong-Mei Guan ◽  
Shi-Yu Huang ◽  
Lu Wu ◽  
Wei-Feng Zhu ◽  
...  

This research sought to study the influence and potentialmechanism of paeoniflorin and albiflorin on strychnine and brucine transport in MDCK-MDR1 cells regulated by P-gp. Cytotoxicity of drugs was tested by MTT assay, and the transport studies were performed in both directions in MDCK-MDR1 cells. The influence of drugs on P-gp ATPase, and the efflux function of P-gp, the expression levels of P-gp and MDR1 mRNA were also estimated. Strychnine and brucine showed well absorption, and the main transport mechanism might be passive diffusion. Verapamil could significantly decrease the efflux rate (ER) of strychnine and brucine, while the ER of strychnine and brucine was increased significantly when co-administrated with paeoniflorin or albiflorin, indicating that paeoniflorin and albiflorin could promote the efflux of these two alkaloids. Strychnine and brucine could activate the activity of P-gp ATPase, suppress the efflux function of P-gp, but have no significant effect on the expression of P-gp. In addition, strychnine could upregulate the expression of MDR1 mRNA. Paeoniflorin and albiflorin could increase the transmembrane transport of strychnine and brucine mediated by P-gp when co-administrated with strychnine or brucine via stimulating the activity of P-gp ATPase, enhancing the efflux function of P-g, increasing the expression levels of MDR1 mRNA and P-gp.


2002 ◽  
Vol 30 (2_suppl) ◽  
pp. 53-59 ◽  
Author(s):  
Tracey Duff ◽  
Simon Carter ◽  
Gemma Feldman ◽  
Gordon McEwan ◽  
Walter Pfaller ◽  
...  

Transepithelial electrical resistance (RT) and the flux of fluorescein isothiocyanate (FITC) across Madin Darby canine kidney (MDCK) strain 1 cells and porcine epithelial kidney (LLC-PK1) monolayers were compared between three laboratories for a range of nephrotoxins. The precision of the REMS AutoSampler was similar to that of the Ussing chamber and the ENDOHM® technique, but superior to using chopstick electrodes, for measurements of resistance. The nephrotoxins used were selective for the proximal tubule, and in all cases, LLC-PK1 cells were more sensitive than MDCK cells. In most cases, change in RT was a more sensitive indicator of damage than alterations in FITC flux. The REMS system provides high intra-plate precision for RT measurements and is a higher throughput system, which is applicable to screening for nephrotoxicity in vitro.


1987 ◽  
Vol 7 (4) ◽  
pp. 1326-1337 ◽  
Author(s):  
S L Warren ◽  
W J Nelson

Madin-Darby canine kidney (MDCK) cells form polarized, multicellular epithelial structures in vitro. Low-level expression of pp60v-src in MDCK cells elicits plasticity in these multicellular structures. Plasticity was revealed by the displacement of cells from mechanically stressed regions of the epithelial monolayers; however, the two-dimensional relationship between the cells in the remainder of the monolayer was maintained. Electron microscopy of multicellular structures revealed abnormal separation of the lateral membranes of adjacent cells and selective uncoupling of the junctional complex; the zonula adherens was disrupted, but the zonula occludens and desmosomes were retained. Significantly, this result was not accompanied by transformation of the cells, as judged by the absence of anchorage-independent growth potential. These results demonstrate a nonmitogenic biological activity of pp60v-src which is experimentally dissociable from transformation. This morphoregulatory action on higher-order epithelial structures may reflect a function of related cellular tyrosine kinases.


2015 ◽  
Vol 89 (11) ◽  
pp. 5935-5948 ◽  
Author(s):  
Mark Zanin ◽  
Bindumadhav Marathe ◽  
Sook-San Wong ◽  
Sun-Woo Yoon ◽  
Emily Collin ◽  
...  

ABSTRACTA balance between the functions of the influenza virus surface proteins hemagglutinin (HA) and neuraminidase (NA) is thought to be important for the transmission of viruses between humans. Here we describe two pandemic H1N1 viruses, A/swine/Virginia/1814-1/2012 and A/swine/Virginia/1814-2/2012 (pH1N1low-1 and -2, respectively), that were isolated from swine symptomatic for influenza. The enzymatic activity of the NA of these viruses was almost undetectable, while the HA binding affinity for α2,6 sialic acids was greater than that of the highly homologous pH1N1 viruses A/swine/Pennsylvania/2436/2012 and A/swine/Minnesota/2499/2012 (pH1N1-1 and -2), which exhibited better-balanced HA and NA activities. Thein vitrogrowth kinetics of pH1N1lowand pH1N1 viruses were similar, but aerosol transmission of pH1N1low-1 was abrogated and transmission via direct contact in ferrets was significantly impaired compared to pH1N1-1, which transmitted by direct and aerosol contact. In normal human bronchial epithelial cells, pH1N1low-1 was significantly inhibited by mucus but pH1N1-1 was not. In Madin-Darby canine kidney cell cultures overlaid with human or swine mucus, human mucus inhibited pH1N1low-1 but swine mucus did not. These data show that the interaction between viruses and mucus may be an important factor in viral transmissibility and could be a barrier for interspecies transmission between humans and swine for influenza viruses.IMPORTANCEA balance between the functions of the influenza virus surface proteins hemagglutinin (HA) and neuraminidase (NA) is thought to be important for transmission of viruses from swine to humans. Here we show that a swine virus with extremely functionally mismatched HA and NAs (pH1N1low-1) cannot transmit via aerosol in ferrets, while another highly homologous virus with HA and NAs that are better matched functionally (pH1N1-1) can transmit via aerosol. These viruses show similar growth kinetics in Madin-Darby canine kidney (MDCK) cells, but pH1N1low-1 is significantly inhibited by mucus in normal human bronchial epithelial cells whereas pH1N1-1 is not. Further, human mucus could inhibit these viruses, but swine mucus could not. These data show that the interaction between viruses and mucus may be an important factor in viral transmissibility and could be a species barrier between humans and swine for influenza viruses.


2010 ◽  
Vol 21 (22) ◽  
pp. 3926-3933 ◽  
Author(s):  
Minji Kim ◽  
Lucy Erin O'Brien ◽  
Sang-Ho Kwon ◽  
Keith E. Mostov

Tubule formation in vitro using Madin-Darby canine kidney (MDCK) epithelial cells consists mainly of two processes. First, the cells undergo a partial epithelial–mesenchymal transition (pEMT), losing polarity and migrating. Second, the cells redifferentiate, forming cords and then tubules with continuous lumens. We have shown previously that extracellular signal-regulated kinase activation is required for pEMT. However, the mechanism of how the pEMT phase is turned off and the redifferentiation phase is initiated is largely unknown. To address the central question of the sequential control of these two phases, we used MDCK cells grown as cysts and treated with hepatocyte growth factor to model tubulogenesis. We show that signal transducer and activator of transcription (STAT)1 controls the sequential progression from the pEMT phase to the redifferentiation phase. Loss of STAT1 prevents redifferentiation. Constitutively active STAT1 allows redifferentiation to occur even when cells are otherwise prevented from progressing beyond the pEMT phase by exogenous activation of Raf. Moreover, tyrosine phosphorylation defective STAT1 partially restored cord formation in such cells, suggesting that STAT1 functions in part as nonnuclear protein mediating signal transduction in this process. Constitutively active or inactive forms of STAT1 did not promote lumen maturation, suggesting this requires a distinct signal.


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