scholarly journals In Vitro Efficacy of Nikkomycin Z against the Human Isolate of the Microsporidian Species Encephalitozoon hellem

2000 ◽  
Vol 44 (11) ◽  
pp. 3012-3016 ◽  
Author(s):  
Elisa Bigliardi ◽  
Anna Maria Bernuzzi ◽  
Silvia Corona ◽  
Simonetta Gatti ◽  
Massimo Scaglia ◽  
...  
Keyword(s):  
Cell Shape ◽  
Cell Damage ◽  
Competitive Inhibitor ◽  
Spore Wall ◽  
Emerging Infections ◽  
Microsporidian Species ◽  
Transmission Electron ◽  
Immunodeficiency Virus ◽  
Nikkomycin Z

ABSTRACT Since 1985 microsporidia have been recognized as a cause of emerging infections in humans, mainly in immunocompromised human immunodeficiency virus-positive subjects. As chitin is a basic component of the microsporidian infective stage, the spore, we evaluated in vitro the susceptibility of a human-derived strain ofEncephalitozoon hellem to nikkomycin Z, a peptide-nucleoside antibiotic known as a competitive inhibitor of chitin synthase enzymes. Transmission electron microscopy showed that this drug, at 25 μg/ml, reduced the number of parasitic foci by about 35% ± standard deviation after 7 days of culture (P< 0.0001) and induced cell damage of both mature and immature spores and also other sporogonic and merogonic stages. In particular, an irregular outline of the cell shape and an abnormally condensed cytoplasm in meronts and sporonts were documented. Also, the polar tubule and the polaroplast membranes appeared disarrayed in the sporoblast stage. The spore wall showed an enlarged endospore and delaminated exospore. Mature spores had a complete cytoplasmic disorganization and a swollen and delaminated cell wall. No ultrastructural cell damage was observed in uninfected control cultures treated with the drug.

scholarly journals Interaction and Assembly of Two Novel Proteins in the Spore Wall of the Microsporidian Species Nosema bombycis and Their Roles in Adherence to and Infection of Host Cells

2015 ◽  
Vol 83 (4) ◽  
pp. 1715-1731 ◽  
Author(s):  
Donglin Yang ◽  
Guoqing Pan ◽  
Xiaoqun Dang ◽  
Yawei Shi ◽  
Chunfeng Li ◽  
...  
Keyword(s):  
Host Cell ◽  
Spore Wall ◽  
Host Cells ◽  
Scaffolding Protein ◽  
Environmental Pressures ◽  
Content Type ◽  
Nosema Bombycis ◽  
Major Function ◽  
Microsporidian Species

Microsporidia are obligate intracellular parasites with rigid spore walls that protect against various environmental pressures. Despite an extensive description of the spore wall, little is known regarding the mechanism by which it is deposited or the role it plays in cell adhesion and infection. In this study, we report the identification and characterization of two novel spore wall proteins, SWP7 and SWP9, in the microsporidian speciesNosema bombycis. SWP7 and SWP9 are mainly localized to the exospore and endospore of mature spores and the cytoplasm of sporonts, respectively. In addition, a portion of SWP9 is targeted to the spore wall of sporoblasts earlier than SWP7 is. Both SWP7 and SWP9 are specifically colocalized to the spore wall in mature spores. Furthermore, immunoprecipitation, far-Western blotting, unreduced SDS-PAGE, and yeast two-hybrid data demonstrated that SWP7 interacted with SWP9. The chitin binding assay showed that, within the total spore protein, SWP9 and SWP7 can bind to the deproteinated chitin spore coats (DCSCs) ofN. bombycis. However, binding of the recombinant protein rSWP7-His to the DCSCs is dependent on the combination of rSWP9–glutathioneS-transferase (GST) with the DCSCs. Finally, rSWP9-GST, anti-SWP9, and anti-SWP7 antibodies decreased spore adhesion and infection of the host cell. In conclusion, SWP7 and SWP9 may have important structural capacities and play significant roles in modulating host cell adherence and infectionin vitro. A possible major function of SWP9 is as a scaffolding protein that supports other proteins (such as SWP7) that form the integrated spore wall ofN. bombycis.

scholarly journals EFFECT OF SOMATOTROPIN AND THYROXINE ON THE IN VITRO DEVELOPMENT OF BOVINE PREANTRAL FOLLICLES

2018 ◽  
Vol 19 (0) ◽  
Author(s):  
Talita Fernandes da Silva ◽  
Sanely Lourenço da Costa ◽  
Eduardo Paulino da Costa ◽  
José Domingos Guimarães
Keyword(s):  
Cell Damage ◽  
Oocyte Diameter ◽  
Minimum Essential Medium ◽  
Recombinant Bovine Somatotropin ◽  
Beneficial Effects ◽  
Transmission Electron ◽  
Survival And Growth ◽  
Vitro Development

Abstract The aim of the study was to evaluate the effect of recombinant bovine somatotropin (rbST) and thyroxine (T4) on survival and growth of bovine preantral ovarian follicles (PAOF) cultured in vitro. Ovarian fragments were collected in local abattoirs and immediately fixed for classical histology and transmission electron microscopy (non-cultured control). The other fragments were then cultured in situ for seven days in minimum essential medium alone (MEM+ - cultured control) or in the presence of 1,000 ng/mL rbST and 20 ng/mL T4, isolated or associated. After seven days, there was a reduction (P<0.05) in the percentage of normal follicles in MEM+ alone or with T4. In oocyte diameter, there was a reduction in MEM+ alone. There was no influence (P>0.01) of the medium used on the follicular diameter of the PAOF cultured for seven days. Ultrastructural analysis showed cell damage. In conclusion, the presence of rbST maintains the rate of morphologically normal follicles during the culture for seven days (observed by optical microscopy), but it does not exert beneficial effects on its ultrastructural integrity and oocyte and follicular growth.

scholarly journals Glycine-Amide Is an Active Metabolite of the Antiretroviral Tripeptide Glycyl-Prolyl-Glycine-Amide

2005 ◽  
Vol 49 (1) ◽  
pp. 40-44 ◽  
Author(s):  
Elin Andersson ◽  
Peter Horal ◽  
Alenka Jejcic ◽  
Stefan Höglund ◽  
Jan Balzarini ◽  
...  
Keyword(s):  
Serial Passage ◽  
Inhibitory Effect ◽  
Capsid Formation ◽  
Transmission Electron ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Simplex Virus ◽  
Hiv 1

ABSTRACT The chemically modified tripeptide glycyl-prolyl-glycine-amide (GPG-NH2) inhibits replication of human immunodeficiency virus (HIV) type 1 (HIV-1) in vitro, probably by interfering with capsid formation. The aim of the present study was to determine whether the metabolites glycyl-proline (GP-OH), glycine (G-OH), prolyl-glycine-amide (PG-NH2), proline (P-OH), and glycine-amide (G-NH2) from proteolytic cleavage may inhibit the replication of HIV-1 in vitro. PG-NH2 has previously been shown to have a modest effect on HIV-1 replication. In the present study we show that G-NH2 exhibits a pronounced inhibitory effect on HIV-1. This effect was not due to a decrease in cell proliferation or viability and could not be shown for herpes simplex virus type 1. The G-NH2 concentration that inhibited virus replication by 50% (IC50) was equimolar to that of GPG-NH2 and ranged from 3 to 41 μM. Transmission electron microscopy revealed that the effect of G-NH2 on HIV-1 morphology was equivalent to that of GPG-NH2 and showed disarranged capsid structures, indicating interference with capsid formation. Serial passage of HIV-infected cells with G-NH2 for more than 20 subcultivations did not decrease the susceptibility to the compound. The results from this study suggest that GPG-NH2 might act as a prodrug and that G-NH2 is an active antiretroviral metabolite.

Antifungal activity of nikkomycin Z against Candida auris

2021 ◽  
Author(s):  
Meghan L Bentz ◽  
Natalie Nunnally ◽  
Shawn R Lockhart ◽  
D Joseph Sexton ◽  
Elizabeth L Berkow
Keyword(s):  
Fungal Pathogen ◽  
Competitive Inhibitor ◽  
Chitin Synthase ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Candida Auris ◽  
Fungal Cell ◽  
The World ◽  
Nikkomycin Z

Abstract Background Nikkomycin Z is a competitive inhibitor of chitin synthase—an enzyme needed for synthesis of the fungal cell wall. Nikkomycin Z shows promise as a treatment for coccidioidomycoses and mixed activity has been described against other fungi and yeast. To our knowledge, it has not previously been tested against the emerging fungal pathogen Candida auris. Objectives To determine the in vitro activity of nikkomycin Z against C. auris. Methods Nikkomycin Z was tested by broth microdilution against a panel of 100 isolates of genetically diverse C. auris from around the world. Results Nikkomycin Z showed mixed activity against the tested isolates, with an MIC range of 0.125 to &gt;64 mg/L. The MIC50 and MIC90 were 2 and 32 mg/L, respectively. Conclusions These findings suggest nikkomycin Z has in vitro activity against some, but not all isolates of C. auris.

A sunscreen nanoparticles polymer based on prolonged period of protection

2021 ◽  
pp. 088391152110617
Author(s):  
Ebtesam A Mohamad ◽  
Monira M Rageh ◽  
Mirhan Mostafa Darwish
Keyword(s):  
Electron Microscopy ◽  
Cell Damage ◽  
Aloe Vera ◽  
Mouse Skin ◽  
Blocking Agent ◽  
Transmission Electron ◽  
Skin Epidermis ◽  
Uv Rays

UV rays are one of the most dangerous factors that harm the skin. There is continuous improvement in getting an effective sunscreen that protects the skin from excessive exposure to UV rays. Typically, phenylbenzimidazole-5-sulfonic acid (PBSA) is used as a sun blocking agent, but its disadvantage is that it can photodegrade and cause cell damage. In our work, PBSA was encapsulated in niosomes nanoparticles then coated with chitosan-aloe vera (CS-nio-aloe/PBSA) to form a carrier polymer with novel and potent properties. This polymer controls PBSA release and epidermal penetration. Characterization of CS-nio-aloe/PBSA polymer nanoparticles through transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS). The carrier polymer release rate was studied in vitro and epidermal permeability to coated PBSA was assessed using mouse skin. The nanoparticle polymer containing sunscreen was effectively prepared with an encapsulation efficiency of 80%. The formulation (CS-nio-aloe/PBSA) was completely deposited on the surface of the skin. This supports its use to protect the skin, and its nanostructures stimulate the release of PBSA for a longer period. Encapsulation of PBSA in CS-nio-aloe nanoparticles could allow for further cellular preservation, UV protection, control of free PBSA, and limited penetration through the mouse skin epidermis.

Multifunctional MnO2-based nanoplatform-induced ferroptosis and apoptosis for synergetic chemoradiotherapy

Nanomedicine ◽  
2021 ◽  
Author(s):  
Xi Li ◽  
Qi Wang ◽  
Sihui Yu ◽  
Minyi Zhang ◽  
Xijian Liu ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Potential Role ◽  
Cell Damage ◽  
Average Diameter ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Transmission Electron

Background: Radiosensitizers that can effectively consume glutathione provide broad prospects for enhancing the efficacy and reducing the side effects of radiotherapy. Aim: To explore the potential role of CuS@mSiO2@MnO2 nanocomposites in synergetic chemoradiotherapy. Methods: Nanocomposites were characterized by transmission electron microscopy, UV-Vis spectrometry and dynamic light scattering and were loaded with doxorubicin (DOX). The uptake and biodistribution of nanocomposites were observed by CCK8 assay, MRI and confocal laser scanning microscopy. The radiosensitization effect of nanocomposites and nanocomposites/DOX was assessed both in vitro and in vivo. Results: In vitro application of nanocomposites, with an average diameter of 30 nm and ζ-potential of 13.2 ± 0.4 mV, in combination with radiotherapy, depleted glutathione and induced ferroptosis and apoptosis. Nanocomposites/DOX exhibited tumor cell damage in vivo. Conclusion: We propose that this glutathione-depleting nanosystem could be a radiosensitizer as well as a drug transporter.

scholarly journals Human immunodeficiency virus 1 (HIV-1) envelope-dependent cell–cell fusion modulation by HIV-positive sera is related to disease progression

2005 ◽  
Vol 86 (7) ◽  
pp. 1961-1966 ◽  
Author(s):  
L. Huerta ◽  
G. Gómez-Icazbalceta ◽  
L. Soto-Ramírez ◽  
M. Viveros-Rogel ◽  
R. Rodríguez ◽  
...  
Keyword(s):  
Cell Fusion ◽  
Cell Damage ◽  
Hiv Positive ◽  
Immunodeficiency Virus ◽  
Load Removal ◽  
Dependent Cell ◽  
Hiv 1 ◽  
Cell Cell

Fusion of CD4+ cells by HIV-1 envelope proteins (Env) is a mechanism of virus spread and cell damage. Production of antibodies able to influence cell–cell fusion in vivo may affect the course of the infection. The effect of sera from 49 HIV-1-positive patients was tested on an in vitro fusion assay using Env-expressing and normal Jurkat T cells labelled with DiI and DiO dyes, and flow cytometry for quantification of cell–cell fusion. Sera varied in their activity on fusion: 69·4 % inhibited, 24·5 % had no effect and 6·1 % enhanced cell fusion. Fusion activity correlated positively with the CD4+ T-cell count and inversely with the viral load. Removal of IgG or IgM from sera reduced or eliminated inhibition and enhancing activities, respectively. Antibodies with inhibitory activity predominate in early and intermediate stages of infection, whereas loss of inhibition or enhancement of fusion correlates with progression to AIDS.

Maytansine-Induced Mitotic Arrest in Human Lymphoblasts

1977 ◽  
Vol 35 ◽  
pp. 460-461
Author(s):  
Tai-Te Chao ◽  
John Sullivan ◽  
Awtar Krishan
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Transmission Electron Microscopy ◽  
Tubulin Polymerization ◽  
Vinca Alkaloids ◽  
Antimitotic Activity ◽  
Transmission Electron ◽  
Flow Microfluorometry ◽  
Brain Tubulin

Maytansine, a novel ansa macrolide (1), has potent anti-tumor and antimitotic activity (2, 3). It blocks cell cycle traverse in mitosis with resultant accumulation of metaphase cells (4). Inhibition of brain tubulin polymerization in vitro by maytansine has also been reported (3). The C-mitotic effect of this drug is similar to that of the well known Vinca- alkaloids, vinblastine and vincristine. This study was carried out to examine the effects of maytansine on the cell cycle traverse and the fine struc- I ture of human lymphoblasts.Log-phase cultures of CCRF-CEM human lymphoblasts were exposed to maytansine concentrations from 10-6 M to 10-10 M for 18 hrs. Aliquots of cells were removed for cell cycle analysis by flow microfluorometry (FMF) (5) and also processed for transmission electron microscopy (TEM). FMF analysis of cells treated with 10-8 M maytansine showed a reduction in the number of G1 cells and a corresponding build-up of cells with G2/M DNA content.

Correlation Between Cellular Functions and Morphological Changes of Human Trophoblast in Vitro

1975 ◽  
Vol 33 ◽  
pp. 600-601
Author(s):  
John C. Garancis ◽  
Robert O. Hussa ◽  
Michael T. Story ◽  
Donald Yorde ◽  
Roland A. Pattillo
Keyword(s):  
Electron Microscopy ◽  
Cellular Proliferation ◽  
Morphological Changes ◽  
Culture Fluid ◽  
Cellular Functions ◽  
Human Trophoblast ◽  
Transmission Electron ◽  
Marked Activity ◽  
Malignant Trophoblast

Human malignant trophoblast cells in continuous culture were incubated for 3 days in medium containing 1 mM N6-O2'-dibutyryl cyclic adenosine 3':5'-monophosphate (dibutyryl cyclic AMP) and 1 mM theophylline. The culture fluid was replenished daily. Stimulated cultures secreted many times more chorionic gonadotropin and estrogens than did control cultures in the absence of increased cellular proliferation. Scanning electron microscopy revealed remarkable surface changes of stimulated cells. Control cells (not stimulated) were smooth or provided with varying numbers of microvilli (Fig. 1). The latter, usually, were short and thin. The surface features of stimulated cells were considerably different. There was marked increase of microvilli which appeared elongated and thick. Many cells were covered with confluent polypoid projections (Fig. 2). Transmission electron microscopy demonstrated marked activity of cytoplasmic organelles. Mitochondria were increased in number and size; some giant forms with numerous cristae were observed.

Hemolysis of erythrocytes by the hemolytic system from the blood-feeding stable fly, Stomoxys calcitrans

1992 ◽  
Vol 50 (1) ◽  
pp. 690-691
Author(s):  
H. J. Kirch ◽  
G. Spates ◽  
R. Droleskey ◽  
W.J. Kloft ◽  
J.R. DeLoach
Keyword(s):  
Blood Feeding ◽  
Stomoxys Calcitrans ◽  
Stable Fly ◽  
Digestive Physiology ◽  
Transmission Electron ◽  
Erythrocyte Lysis ◽  
Mammalian Blood ◽  
Bovine Erythrocytes ◽  
Potential Tool

Blood feeding insects have to rely on the protein content of mammalian blood to insure reproduction. A substantial quantity of protein is provided by hemoglobin present in erythrocytes. Access to hemoglobin is accomplished only via erythrocyte lysis. It has been shown that midgut homogenates from the blood feeding stable fly, Stomoxys calcitrans, contain free fatty acids and it was proposed that these detergent-like compounds play a major role as hemolysins in the digestive physiology of this species. More recently sphingomyelinase activity was detected in midgut preparations of this fly, which would provide a potential tool for the enzymatic cleavage of the erythrocyte's membrane sphingomyelin. The action of specific hemolytic factors should affect the erythrocyte's morphology. The shape of bovine erythrocytes undergoing in vitro hemolysis by crude midgut homogenates from the stable fly was examined by scanning and transmission electron microscopy.

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