scholarly journals Antiviral Action of Hydromethanolic Extract of Geopropolis fromScaptotrigona posticaagainst Antiherpes Simplex Virus (HSV-1)

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Guilherme Rabelo Coelho ◽  
Ronaldo Zucatelli Mendonça ◽  
Karina de Senna Vilar ◽  
Cristina Adelaide Figueiredo ◽  
Juliana Cuoco Badari ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antiviral Activity ◽  
Viral Replication ◽  
Viral Dna ◽  
Replication Complex ◽  
Transmission Electron ◽  
Scaptotrigona Postica ◽  
Simplex Virus ◽  
First Time

The studies on chemical composition and biological activity of propolis had focused mainly on speciesApis melliferaL. (Hymenoptera: Apidae). There are few studies about the uncommon propolis collected by stingless bees of the Meliponini tribe known as geopropolis. The geopropolis fromScaptotrigona posticawas collected in the region of Barra do Corda, Maranhão state, Brazil. The chemical analysis of hydromethanolic extract of this geopropolis (HMG) was carried out through HPLC-DAD-ESI-MS/MS and the main constituents found were pyrrolizidine alkaloids and C-glycosyl flavones. The presence of alkaloids in extracts of propolis is detected for the first time in this sample. The antiviral activity of HMG was evaluated through viral DNA quantification experiments and electron microscopy experiments. Quantification of viral DNA from herpes virus showed reduction of about 98% in all conditions and concentration tested of the HMG extract. The results obtained were corroborated by transmission electron microscopy, in which the images did not show particle or viral replication complex. The antiviral activity of C-glycosyl flavones was reported for a variety of viruses, being observed at different points in the viral replication. This work is the first report about the antiviral activity of geopropolis fromScaptotrigona postica, in vitro, against antiherpes simplex virus (HSV).

scholarly journals Schwann Cell Autophagy and Necrosis as Mechanisms of Cell Death by Acanthamoeba

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 458
Author(s):  
Ismael Castelan-Ramírez ◽  
Lizbeth Salazar-Villatoro ◽  
Bibiana Chávez-Munguía ◽  
Citlaltepetl Salinas-Lara ◽  
Carlos Sánchez-Garibay ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Confocal Microscopy ◽  
Rattus Norvegicus ◽  
Multilamellar Bodies ◽  
Transmission Electron ◽  
Granulomatous Amoebic Encephalitis ◽  
Etiological Agents ◽  
First Time

Amoebae of the genus Acanthamoeba are etiological agents of granulomatous amoebic encephalitis (GAE). Recently, through an in vivo GAE model, Acanthamoeba trophozoites were immunolocalized in contact with the peripheral nervous system (PNS) cells—Schwann cells (SC). In this study, we analyzed in greater detail the in vitro early morphological events (1, 2, 3, and 4 h) during the interaction of A. culbertsoni trophozoites (ATCC 30171) with SC from Rattus norvegicus (ATCC CRL-2941). Samples were processed for scanning and transmission electron microscopy as well as confocal microscopy. After 1 h of interaction, amoebae were observed to be adhered to the SC cultures, emitting sucker-like structures associated with micro-phagocytic channels. In addition, evidence of necrosis was identified since edematous organelles as well as multivesicular and multilamellar bodies characteristics of autophagy were detected. At 2 h, trophozoites migrated beneath the SC culture in which necrosis and autophagy persisted. By 3 and 4 h, extensive lytic zones were observed. SC necrosis was confirmed by confocal microscopy. We reported for the first time the induction of autophagic and necrotic processes in PNS cells, associated in part with the contact-dependent pathogenic mechanisms of A. culbertsoni trophozoites.

Steps of nuclear pore complex disassembly and reassembly during mitosis in earlyDrosophilaembryos

2001 ◽  
Vol 114 (20) ◽  
pp. 3607-3618 ◽  
Author(s):  
Elena Kiseleva ◽  
Sandra Rutherford ◽  
Laura M. Cotter ◽  
Terence D. Allen ◽  
Martin W. Goldberg
Keyword(s):  
Electron Microscopy ◽  
Nuclear Pore Complex ◽  
Drosophila Embryo ◽  
Nuclear Pore ◽  
Polar Regions ◽  
Transmission Electron ◽  
Vitro Model ◽  
First Time

The mechanisms of nuclear pore complex (NPC) assembly and disassembly during mitosis in vivo are not well defined. To address this and to identify the steps of the NPC disassembly and assembly, we investigated Drosophila embryo nuclear structure at the syncytial stage of early development using field emission scanning electron microscopy (FESEM), a high resolution surface imaging technique, and transmission electron microscopy. Nuclear division in syncytial embryos is characterized by semi-closed mitosis, during which the nuclear membranes are ruptured only at the polar regions and are arranged into an inner double membrane surrounded by an additional ‘spindle envelope’. FESEM analysis of the steps of this process as viewed on the surface of the dividing nucleus confirm our previous in vitro model for the assembly of the NPCs via a series of structural intermediates, showing for the first time a temporal progression from one intermediate to the next. Nascent NPCs initially appear to form at the site of fusion between the mitotic nuclear envelope and the overlying spindle membrane. A model for NPC disassembly is offered that starts with the release of the central transporter and the removal of the cytoplasmic ring subunits before the star ring.

scholarly journals Novel Cationic Meso-Arylporphyrins and Their Antiviral Activity against HSV-1

2021 ◽  
Vol 14 (3) ◽  
pp. 242
Author(s):  
Kseniya A. Zhdanova ◽  
Inga O. Savelyeva ◽  
Artem V. Ezhov ◽  
Andrey P. Zhdanov ◽  
Konstantin Yu. Zhizhin ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Replication ◽  
Polymeric Micelles ◽  
Antiviral Agents ◽  
Pluronic F127 ◽  
High Concentration ◽  
Noticeable Effect ◽  
Simplex Virus ◽  
Hsv 1

This work is devoted to the search for new antiherpes simplex virus type 1 (HSV-1) drugs among synthetic tetrapyrroles and to an investigation of their antiviral properties under nonphotodynamic conditions. In this study, novel amphiphilic 5,10,15,20-tetrakis(4-(3-pyridyl-n-propanoyl)oxyphenyl)porphyrin tetrabromide (3a), 5,10,15,20-tetrakis(4-(6-pyridyl-n-hexanoyl)oxyphenyl)porphyrin tetrabromide (3b) and known 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetraiodide (TMePyP) were synthesized, and their dark antiviral activity in vitro against HSV-1 was studied. The influence of porphyrin’s nanosized delivery vehicles based on Pluronic F127 on anti-HSV-1 activity was estimated. All the received compounds 3a, 3b and TMePyP showed virucidal efficiency and had an effect on viral replication stages. The new compound 3b showed the highest antiviral activity, close to 100%, with the lowest concentration, while the maximum TMePyP activity was observed with a high concentration; porphyrin 3a was the least active. The inclusion of the synthesized compounds in Pluronic F-127 polymeric micelles had a noticeable effect on antiviral activity only at higher porphyrin concentrations. Action of the received compounds differs by influence on the early or later reproduction stages. While 3a and TMePyP acted on all stages of the viral replication cycle, porphyrin 3b inhibited viral replication during the early stages of infection. The resulting compounds are promising for the development of utilitarian antiviral agents and, possibly, medical antiviral drugs.

scholarly journals Estimation, morphometry and ultrastructure of ovarian preantral follicle population in agouti (Dasyprocta leporina)

2018 ◽  
Vol 38 (1) ◽  
pp. 175-182 ◽  
Author(s):  
Erica A.A. Santos ◽  
Gabriela L. Lima ◽  
Erica C.G. Praxedes ◽  
Andréia M. Silva ◽  
Keilla M. Maia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ultrastructural Analysis ◽  
Preantral Follicle ◽  
Transmission Electron ◽  
The Mean ◽  
First Time ◽  
Further Development

ABSTRACT: The aim of this study was to characterize the preantral ovarian follicular population in agoutis (D. leporina) by estimating the number of follicles at each developmental category, and also describe the morphometry and the specific features of the follicle and the oocyte by using light and transmission electron microscopy. The length of each ovary was measured using a caliper rule, longitudinally sectioned into two halves and both were immediately fixed to perform the estimation of follicular population and ultrastructural analysis. The mean (±S.E.M.) population of follicular per pair of ovary was estimated at 4419.8±532.26 and 5397.52±574.91 for right and left ovaries, respectively, but no differences were observed between them. The diameters for follicles, oocyte and nuclei were: 18.62±3.40μm, 12.28±2.37μm and 6.10±0.93μm for primordial, 23.75±5.70μm, 14.22±3.00μm and 6.70±1.24μm for primary and 88.55±17.61μm, 52.85±17.56μm and 22.33±17.61μm for secondary follicles, respectively. The most of the follicles found belonged to the primordial category (86.63%), followed by primary (13.01%) and secondary (0.35%) one. Additionally, polyovular follicles were observed in all the animals and they represented 7.51% of the total follicles counted. The ultrastructural analysis showed that the oocyte presented a central and regular nuclei, displaying a homogenous mass. Among the organelles, the mitochondria were the most abundant and the oocyte Golgi apparatus was rarely observed. In conclusion, this work shows for the first time the characterization of the population of preantral follicles in the ovary of Dasyprocta leporina. Those information will be useful for further development and adaptation of biotechniques such as germplasm cryopreservation and in vitro gametes manipulation.

scholarly journals A New Sterilization Strategy Using TiO2 Nanotubes for Production of Free Radicals that Eliminate Viruses and Application of a Treatment Strategy to Combat Infections Caused by Emerging SARS-CoV-2 during the COVID-19 Pandemic

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 680
Author(s):  
Reham Z. Hamza ◽  
Adil A. Gobouri ◽  
Hatim M. Al-Yasi ◽  
Tarek A. Al-Talhi ◽  
Samy M. El-Megharbel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Antiviral Activity ◽  
Inhibitory Concentration ◽  
Tio2 Nps ◽  
Transmission Electron ◽  
Low Concentrations ◽  
Ft Ir ◽  
Chemical Purity

Synthesized titanium oxide nanoparticles (TiO2-NPs) nanotubes were used for the disinfection of new emerging corona virus-19 (SARS-CoV-2) in this study. The newly synthesized TiO2-NPs (nanotubes) were characterized by chemical spectroscopic analysis Fourier-transform infrared spectroscopy and ultraviolet FT-IR and UV. The chemical purity and Zeta potential distribution of the TiO2-NPs (nanotubes) were evaluated to confirm their nano-range, and their surface morphology was determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and energy dispersive X-ray analysis (EDX). The antiviral activity of the TiO2-NPs (nanotubes) against SARS-CoV-2 was evaluated using 10% (Dimethyl sulfoxide) DMSO and dist.H2O using a cytotoxicity assay and inhibitory concentration assay (to determine the cytotoxic half concentration CC50 and half maximal inhibitory concentration IC50). The current results confirmed that TiO2-NPs exhibit strong anti-SARS-CoV-2 activity at very low cytotoxic concentrations in vitro with a non-significant selectivity index (CC50/IC50 ≤ 1). The obtained results indicate that TiO2-NPs and nanotubes have potent antiviral activity at a very low concentrations (IC50 = 568.6 ng/mL), with a weak cytotoxic effect on the cellular host (CC50 = 399.1 ng/mL). Thus, we highly recommend the use of TiO2-NPs (nanotubes) in vitro and in wall coatings as a potent disinfectant to combat SARS-CoV-2 with little irritation of the cellular hosts. Furthermore, we also recommend more and excessive prospective studies on the complexation of natural active or natural compounds with TiO2-NPs (nanotubes) to minimize their cytotoxicity, enhance their antiviral activity, and increase their inhibition of SARS-CoV-2.

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.

TAMM HORSFALL PROTEIN: THE MEN BEHIND THE EPONYM

2019 ◽  
Vol 23 (2) ◽  
pp. 117-119 ◽  
Author(s):  
D. N. Paskalev ◽  
B. T. Galunska ◽  
D. Petkova-Valkova
Keyword(s):  
Viral Replication ◽  
Research Team ◽  
Molecular Mechanisms ◽  
Thick Ascending Limb ◽  
Rockefeller Institute ◽  
The Usa ◽  
Natural Inhibitor ◽  
Simplex Virus ◽  
First Time ◽  
New Protein

Tamm–Horsfall Protein (uromodulin) is named after Igor Tamm and Franc Horsfall Jr who described it for the first time in 1952. It is a glycoprotein, secreted by the cells in the thick ascending limb of the loop of Henle. This protein will perform a number of important pathophysiological functions, including protection against uroinfections, especially caused by E. Сoli, and protection against formation of calcium concernments in the kidney. Igor Tamm (1922-1995) is an outstanding cytologist, virologist and biochemist. He is one of the pioneers in the study of viral replication. He was born in Estonia and died in the USA. In 1964 he was elected for a professorship in Rockefeller Institute for Medical Research, where has been working continuously. Since 1959, he became a head of the virology lab established by his mentor and co-author Franc Horsfall. In the course of studies on the natural inhibitor of viral replication, Tamm and Horsfall isolated and characterized biochemically a new protein named after their names. Franc Lappin Horsfall Jr (1906-1971) was a well-known clinician and virologist with remarkable achievements in internal medicine. He was born and died in the USA. He worked in the Rockefeller Hospital from 1934 to 1960, then in the Center for Cancer Research at the Sloan-Kettering Institute. Here he was a leader of a research team studying the molecular mechanisms of immunity, the effects of chemotherapy with benzimidazole compounds (together with I. Tamm), coxsackie viruses, herpes simplex virus, etc. 

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

scholarly journals In vitro biological activity of Hydroclathrus clathratus and its use as an extracellular bioreductant for silver nanoparticle formation

2020 ◽  
Vol 9 (1) ◽  
pp. 416-428 ◽  
Author(s):  
Raghad R. Alzahrani ◽  
Manal M. Alkhulaifi ◽  
Nouf M. Al-Enazi
Keyword(s):  
Biological Activity ◽  
Unsaturated Fatty Acids ◽  
Multidrug Resistant ◽  
Chemical Components ◽  
Resistant Bacteria ◽  
Transmission Electron ◽  
Hydroclathrus Clathratus ◽  
Adaptive Nature ◽  
First Time

AbstractThe adaptive nature of algae results in producing unique chemical components that are gaining attention due to their efficiency in many fields and abundance. In this study, we screened the phytochemicals from the brown alga Hydroclathrus clathratus and tested its ability to produce silver nanoparticles (AgNPs) extracellularly for the first time. Lastly, we investigated its biological activity against a variety of bacteria. The biosynthesized nanoparticles were characterized by UV-visible spectroscopy, Fourier-transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy, and energy-dispersive spectroscopy. The biological efficacy of AgNPs was tested against eighteen different bacteria, including seven multidrug-resistant bacteria. Phytochemical screening of the alga revealed the presence of saturated and unsaturated fatty acids, sugars, carboxylic acid derivatives, triterpenoids, steroids, and other components. Formed AgNPs were stable and ranged in size between 7 and 83 nm and presented a variety of shapes. Acinetobacter baumannii, Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), and MDR A. baumannii were the most affected among the bacteria. The biofilm formation and development assay presented a noteworthy activity against MRSA, with an inhibition percentage of 99%. Acknowledging the future of nano-antibiotics encourages scientists to explore and enhance their potency, notably if they were obtained using green, rapid, and efficient methods.

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