Search results for "Fluorescence"
showing 10 items of 2463 documents
Flow cytometric analysis of chronic and acute toxicity of copper(II) on the marine dinoflagellateAmphidinium carterae
2001
Background Copper(II) is a heavy metal whose levels have increased in some marine ecosystems to polluting levels. Dinoflagellates, an important phytoplankton group, are at the base of aquatic food chains and bioaccumulation of copper by these microorganisms can result in complex ecosystem alterations, so we investigated how copper disturbs those cells. Methods Cytotoxic effects of sublethal and lethal copper concentrations ranging from 4.2 nM (control condition) to 3.13 μM estimated labile copper were studied in batch cultures of Amphidinium carterae. Cell morphology, motility, autofluorescence, and fluorescein diacetate (FDA)–dependent fluorescence generation were evaluated by flow cytomet…
Biotehnoloģisko metožu izmantošana vietējās selekcijas apšu hibrīdu pavairošanā audu kultūrā
2015
Pavairojot apšu hibrīdus audu kultūrā, nākas saskarties ar tādām problēmām kā kultivēšanas dārdzība, infekcijas un kultūras ilgtermiņa uzturēšanas izmaksas. Darba mērķis bija izstrādāt zinātnisko pamatu vietējās selekcijas apšu hibrīdu pavairošanas un uzglabāšanas efektivitātes paaugstināšanai. Darbā pārbaudīta HgCl2 virsmas sterilizācijas tehnika un tās ietekme uz mikrospraudeņu vitalitāti, kā reprezentatīvo rādītāju izmantojot hlorofila a fluorescences parametru vērtības; ex vitro pavairošanas pieeja; mikrospraudeņu uzglabāšanas iespējas +50C temperatūrā. Iegūtie rezultāti liecina, ka HgCl2 virsmas sterilizācija ir izmantojama mikrospraudeņu dezinfekcijai un augu vitalitāti būtiski neiete…
Conformational Dynamics of the Dengue Virus Protease Revealed by Fluorescence Correlation and Single-Molecule FRET Studies.
2021
The dengue virus protease (DENV-PR) represents an attractive target for counteracting DENV infections. It is generally assumed that DENV-PR can exist in an open and a closed conformation and that active site directed ligands stabilize the closed state. While crystal structures of both the open and the closed conformation were successfully resolved, information about the prevalence of these conformations in solution remains elusive. Herein, we address the question of whether there is an equilibrium between different conformations in solution which can be influenced by addition of a competitive inhibitor. To this end, DENV-PR was statistically labeled by two dye molecules constituting a FRET …
Human Papillomavirus Types 16, 18, and 31 Share Similar Endocytic Requirements for Entry
2013
ABSTRACT Human papillomavirus type 18 (HPV18), one of the HPVs with malignant potential, enters cells by an unknown endocytic mechanism. The key cellular requirements for HPV18 endocytosis were tested in comparison to those for HPV16 and -31 endocytoses. HPV18 (like HPV16 and -31) entry was independent of clathrin, caveolin, dynamin, and lipid rafts but required actin polymerization and tetraspanin CD151, and the viruses were routed to the same LAMP-1-positive compartment. Hence, the viruses shared similar cellular requirements for endocytic entry.
Baculovirus-mediated immediate-early gene expression and nuclear reorganization in human cells
2007
Baculovirus, Autographa californica multiple nucleopolyhedrovirus (AcMNPV), has the ability to transduce mammalian cell lines without replication. The general objective of this study was to detect the transcription and expression of viral immediate-early genes in human cells and to examine the interactions between viral components and subnuclear structures. Viral capsids were seen in large, discrete foci in nuclei of both dividing and non-dividing human cells. Concurrently, the transcription of viral immediate-early transregulator genes (ie-1, ie-2) and translation of IE-2 protein were detected. Quantitative microscopy imaging and analysis showed that virus transduction altered the size of …
Rapid and sensitive detection of metapneumovirus in clinical specimens by indirect fluorescence assay using a monoclonal antibody.
2008
Human metapneumovirus, with two known genotypes named A and B, is associated with mild respiratory symptoms to severe LRTI in children, high-risk adults and the elderly. Rapid and reliable methods of hMPV detection in clinical samples are essential to implement appropriate care, to better understand the pathology of hMPV and to determine its epidemiology. Respiratory samples from 1,386 patients collected during 2 consecutive years were screened for hMPV using indirect immunofluorescence (IFA) assay with a monoclonal antibody. Forty-three patients tested positive for hMPV by the IFA method. In parallel, the samples were examined with RT-PCR on the F gene. Of these, 41 specimens were RT-PCR p…
PTC124-mediated translational readthrough of a nonsense mutation causing Usher syndrome type 1C.
2011
We investigated the therapeutic potential of the premature termination codon (PTC) readthrough-inducing drug PTC124 in treating the retinal phenotype of Usher syndrome, caused by a nonsense mutation in the USH1C gene. Applications in cell culture, organotypic retina cultures, and mice in vivo revealed significant readthrough and the recovery of protein function. In comparison with other readthrough drugs, namely the clinically approved readthrough-inducing aminoglycoside gentamicin, PTC124 exhibits significant better retinal biocompatibility. Its high readthrough efficiency in combination with excellent biocompatibility makes PTC124 a promising therapeutic agent for PTCs in USH1C, as well a…
Quantitative microscopy reveals stepwise alteration of chromatin structure during herpesvirus infection
2019
During lytic herpes simplex virus 1 (HSV-1) infection, the expansion of the viral replication compartments leads to an enrichment of the host chromatin in the peripheral nucleoplasm. We have shown previously that HSV-1 infection induces the formation of channels through the compacted peripheral chromatin. Here, we used three-dimensional confocal and expansion microscopy, soft X-ray tomography, electron microscopy, and random walk simulations to analyze the kinetics of host chromatin redistribution and capsid localization relative to their egress site at the nuclear envelope. Our data demonstrated a gradual increase in chromatin marginalization, and the kinetics of chromatin smoothening arou…
Hipofīzes adenomu šūnu raksturojums
2018
Hipofīzes adenoma ir populācijā bieži sastopams labdabīgs smadzeņu audzējs. Šobrīd trūkst informācijas par iespējamiem audzēja veidošanās mehānismiem un tā attīstību veicinošām mutācijām. Šajā pētījumā ir apkopoti 10 hipofīzes adenomu pacientu dati, kas iegūti ar molekulārām un šūnu bioloģijas metodēm. No hipofīzes adenomu operāciju materiāla tika iegūtas heterogēnas šūnu kultūras, kas tika raksturotas pēc audzēja un cilmes šūnu marķieriem, ka arī mutāciju spektra, izmantojot imūnfluorescentās krāsošanas, plūsmas citometrijas, vienas šūnas pilna genoma amplifikācijas un eksonu sekvenēšanas metodes. Rezultāti liecina, ka no hipofīzes adenomas paraugiem ir iespējams iegūt dzīvotspējīgas sfēra…
Mechanisms of irreversible aquaporin-10 inhibition by organogold compounds studied by combined biophysical methods and atomistic simulations
2021
Abstract The inhibition of glycerol permeation via human aquaporin-10 (hAQP10) by organometallic gold complexes has been studied by stopped-flow fluorescence spectroscopy, and its mechanism has been described using molecular modelling and atomistic simulations. The most effective hAQP10 inhibitors are cyclometalated Au(III) C^N compounds known to efficiently react with cysteine residues leading to the formation of irreversible C–S bonds. Functional assays also demonstrate the irreversibility of the binding to hAQP10 by the organometallic complexes. The obtained computational results by metadynamics show that the local arylation of Cys209 in hAQP10 by one of the gold inhibitors is mapped int…