scholarly journals Anti-TMV Activities of Pantoea agglomerans Lipopolysaccharides in vitro

2021 ◽  
Vol 83 (2) ◽  
pp. 64-72
Author(s):  
T.V. Bulyhina ◽  
◽  
A.M. Kyrychenko ◽  
M.S. Kharchuk ◽  
L.D. Varbanets ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Lipid A ◽  
Datura Stramonium ◽  
Inhibitory Effect ◽  
Pantoea Agglomerans ◽  
Structural Components ◽  
Core Oligosaccharide ◽  
Electron Microscopic ◽  
Phytopathogenic Bacteria

Today there are no antiviral drugs of chemical nature that can completely cure virus-infected plants. The fact that their effect is limited to minimizing the pathogenic effect of viruses motivates many researchers to look for alternatives. In recent years it has been shown that lipopolysaccharides (LPS) of some bacteria, in particular representatives of the Pseudomonas genus were active against Tobacco mosaic virus (TMV). Therefore, we were interested in the additional study of LPS of phytopathogenic bacteria Pantoea agglomerans as a possible drug acting as antiviral agent. The aim of current study was to evaluate the antiviral activities of LPS obtained from phytopathogenic bacteria P. agglomerans against TMV in vitro. Methods. The antiviral activity of LPS preparations was investigated in vitro and assessed according to the inhibition percentage towards the number of local lesions in Datura stramonium leaves. P. agglomerans LPS was isolated from dry bacterial mass by phenol-water method. LPS mild acid degradation allowed to separate O-specific polysaccharide (OPS) and lipid A, which structures were identified by us earlier. The analysis of TMV and LPS interactions was carried out using a JEM 1400 transmission electron microscope (Jeol, Japan) at an accelerating voltage of 80 kV. Results. The most active were LPS preparations from P. agglomerans P324 and 8488. In vitro inhibitory efficacies of TMV infection by these LPS preparations was 59 and 60% respectively. LPS preparations of P. agglomerans 7969, 7604 and 9637, on the contrary, were inactive. Comparative analysis of the antiviral activity of LPS structural components of two P. agglomerans P324 and 7604 strains showed that the greatest inhibitory effect on the infectivity of TMV was exhibited by P. agglomerans P324 lipid A, the antiviral activity of which practically did not differ from the activity of the LPS molecule (it was lower by 7%). At the same time, the inhibitory effect of P. agglomerans 7604 core oligosaccharide (OG-core) against TMV was slightly higher compared to the effect of the whole LPS molecule. It can be assumed that the OG-core stimulated the defense mechanisms of plants and prevented the development of viral infection. Electron microscopic dates have shown that P. agglomerans P324 LPS at the concentration of 1 mg/ml influenced on freely located virions in the control causing “sticking” thus forming dense clusters, complexes or “bundles” of the virus. The individual structural components of P. agglomerans P324 LPS (lipid A and OG-core) did not have the same effect as a whole molecule. Conclusions. The study of the antiviral activity of LPS in the model system TMV – Datura stramonium L. plants showed that the most active were LPS preparations of only two strains of P. agglomerans (P324 and 8488) while the other seven strains were inactive. Individual structural components: lipid A from P. agglomerans P324 and OG-core from P. agglomerans 7604 decreased the infectivity of TMV by 7 and 15% higher than the initial LPS molecule. According to electron microscopy data the virions sticked together forming the dense clusters in case of the direct LPS-virus contacting in vitro whereas in the control it was observed just a single free virus particles. A more detailed study of the effect of individual structural components will help to understand the regularities of the LPS structure effect on TMV infectivity.

scholarly journals Antiviral Activity ofIsatis indigoticaExtract and Its Derived Indirubin against Japanese Encephalitis Virus

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Shu-Jen Chang ◽  
Yi-Chih Chang ◽  
Kai-Zen Lu ◽  
Yi-Yun Tsou ◽  
Cheng-Wen Lin
Keyword(s):  
Antiviral Activity ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Antiviral Effect ◽  
Inhibitory Effect ◽  
Encephalitis Virus ◽  
Simultaneous Treatment ◽  
Virus Attachment ◽  
Antiviral Activities

Isatis indigoticais widely used in Chinese Traditional Medicine for clinical treatment of virus infection, tumor, and inflammation, yet its antiviral activities remain unclear. This study probed antiviral activity ofI. indigoticaextract and its marker compounds against Japanese encephalitis virus (JEV).I. indigoticamethanol extract, indigo, and indirubin proved less cytotoxic than other components, showing inhibitory effect (concentration-dependent) on JEV replicationin vitro. Time-of-addition experiments proved the extract, indigo, and indirubin with potent antiviral effect by pretreatment (before infection) or simultaneous treatment (during infection), but not posttreatment (after entry). Antiviral action of these agents showed correlation with blocking virus attachment and exhibited potent virucidal activity. In particular, indirubin had strong protective ability in a mouse model with lethal JEV challenge. The study could yield anti-JEV agents.

scholarly journals Roles of 3-Deoxy-d-manno-2-Octulosonic Acid Transferase from Moraxella catarrhalis in Lipooligosaccharide Biosynthesis and Virulence

2005 ◽  
Vol 73 (7) ◽  
pp. 4222-4230 ◽  
Author(s):  
Daxin Peng ◽  
Biswa P. Choudhury ◽  
Ronald S. Petralia ◽  
Russell W. Carlson ◽  
Xin-Xing Gu
Keyword(s):  
Moraxella Catarrhalis ◽  
Lipid A ◽  
Therapeutic Interventions ◽  
Core Oligosaccharide ◽  
Gene Encoding ◽  
Oligosaccharide Moiety ◽  
Normal Human ◽  
Human Infections

ABSTRACT Lipooligosaccharide (LOS), a major outer membrane component of Moraxella catarrhalis, is a possible virulence factor in the pathogenesis of human infections caused by the organism. However, information about the roles of the oligosaccharide chain from LOS in bacterial infection remains limited. Here, a kdtA gene encoding 3-deoxy-d-manno-2-octulosonic acid (Kdo) transferase, which is responsible for adding Kdo residues to the lipid A portion of the LOS, was identified by transposon mutagenesis and construction of an isogenic kdtA mutant in strain O35E. The resulting O35EkdtA mutant produced only lipid A without any core oligosaccharide, and it was viable. Physicochemical and biological analysis revealed that the mutant was susceptible to hydrophobic reagents and a hydrophilic glycopeptide and was sensitive to bactericidal activity of normal human serum. Importantly, the mutant showed decreased toxicity by the Limulus amebocyte lysate assay, reduced adherence to human epithelial cells, and enhanced clearance in lungs and nasopharynx in a mouse aerosol challenge model. These data suggest that the oligosaccharide moiety of the LOS is important for the biological activity of the LOS and the virulence capability of the bacteria in vitro and in vivo. This study may bring new insights into novel vaccines or therapeutic interventions against M. catarrhalis infections.

Antiviral Activity of Some Hydroxycoumarin Derivatives

1996 ◽  
Vol 51 (7-8) ◽  
pp. 558-562 ◽  
Author(s):  
Angel S. Galabov ◽  
Tanya Iosifova ◽  
Elka Vassileva ◽  
Ivanka Kostova
Keyword(s):  
Antiviral Activity ◽  
Newcastle Disease Virus ◽  
Disease Virus ◽  
Virus Replication ◽  
Cell Cultures ◽  
Newcastle Disease ◽  
Inhibitory Effect ◽  
Marked Inhibitory Effect ◽  
Herpès Virus

Abstract Esculetin (6,7-dihydroxycoumarin) and its diacetate exhibited a marked inhibitory effect on Newcastle disease virus replication in cell cultures at concentrations of 36 jam and 62 jam, respectively. These compounds were selected from ten hydroxycoumarin derivatives through an in vitro antiviral screen involving viruses of the picorna-, orthomyxo-, paramyxo-, and herpes virus families.

scholarly journals In Vitro Antimicrobial, Antiviral and Cytotoxicity Activities of Aspergillus oryzae Isolated From El-Baida Marsh in Algeria

2020 ◽  
Vol 10 (4) ◽  
pp. 191-195
Author(s):  
Nacef Houda Sara ◽  
Belhattab Rachid ◽  
Galvez Julio ◽  
Rodriguez-Sojo María Jesus ◽  
Vezza Teresa
Keyword(s):  
Antimicrobial Activity ◽  
Antiviral Activity ◽  
Aspergillus Oryzae ◽  
Antimicrobial Property ◽  
Inhibition Zone ◽  
Inhibitory Effect ◽  
Host Cells ◽  
Minimal Inhibitory Concentrations ◽  
Cytotoxicity Activity

This work covers the study of antimicrobial and antiviral activities of the Aspergillus oryzae strain isolated from saline soil (El-Baida marsh in Algeria). The crude extract obtained with ethyl acetate displayed antimicrobial activity against Gram-positive and Gram-negative bacteria and the yeast Candida albicans with a mean of 16.69 mm of inhibition zone and a minimal inhibitory concentrations MICs between 7.28 and 21.85 μgmL-1. We also assessed the antiviral activity against Herpes simplex-2 Virus (HSV-2), in which no inhibitory effect was exhibited. In addition, cytotoxicity activity was tested in Caco-2 and RAW 264, a human epithelial and a murine macrophage cell line, respectively, revealing a no-toxic effect of the extract. The studied isolate extract possesses an antimicrobial property and its non-toxicity to the host cells becomes very important, and can be exploited for the production of new pharmacological and biotechnological agents.        Keywords: Aspergillus oryzae, antimicrobial activity, antiviral activity, cytotoxicity, fungal extraction.

scholarly journals Screening of in vitro antiviral activity of purified terpenoid extracts of selected sea weeds against chikungunya virus

2020 ◽  
pp. 320-324
Author(s):  
Sabira Siraj Sumayya ◽  
Abdulhadeef Shereefa Lubaina ◽  
Kumaraswamy Murugan
Keyword(s):  
Antiviral Activity ◽  
Chikungunya Virus ◽  
Kappaphycus Alvarezii ◽  
Inhibitory Effect ◽  
Hypnea Musciformis ◽  
High Incidence ◽  
Medicinal Properties ◽  
Inhibitory Potential ◽  
Layer Chromatography

Currently, the search of novel phytochemicals with unique biological potentialities is a pre-requisite for the designing ideal drugs for the human kind. Sea weeds are bioresources with a broad spectrum of medicinal properties with minimal side effects. Kerala, the Southern state of India reported high incidence of Chikungunya virus (CHIKV) infections in the last several tears. No specific virucidal therapy or effective vaccines are available. This emphasizes the need of searching for phytochemicals as drugs with less cost and more effective. Therefore, an attempt was made in screening purified terpenoid extracts of selected sea weeds as anti-CHIKV potential. In this study the terpenoids composition from the red algae Hypnea musciformis, Kappaphycus alvarezii and Gracillaria dura were identified and analyzed by thin layer chromatography and Gas chromatography- Mass spectrum. The methanolic extract of seaweeds was purified by column chromatography and each fraction was eluted by using petroleum ether and ethyl acetate as solvent combination. The analysis of the purified fraction of H. musciformis and K. alvarezii revealed the presence of 8 terpenoid fractions, and G. dura showed only 4 major components respectively. Vero cell lines were employed in the antiviral assays, infected to CHIKV, and treated with varied doses of purified terpenoid extracts. In the antiviral activity, terpenoid extracts of G. dura showed remarkable and promising EC50 inhibitory effect at 1.25 μg/ml. Further, the terpenoid extracts displayed efficient virucidal activity against CHIKV (inhibit around 90%) with 5 μg/ml dosage. As the last phase, terpenoid extracts added at time intervals of 0, 1, 2, 3 post-infection periods still maintained a significant inhibitory potential against CHIKV viral replication. Thus, the overall study suggests that the terpenoid extracts of G. dura may be effectively used in the prevention and treatment of CHIKV infections. Clinical studies may be warranted for designing a promising new anti-CHIKV drug.

scholarly journals Ribavirin shows antiviral activity against SARS-CoV-2 and downregulates the activity of TMPRSS2 and the expression of ACE2 in vitro

2021 ◽  
pp. 1-12 ◽  
Author(s):  
Mehmet Altay Unal ◽  
Ceylan Verda Bitirim ◽  
Gokce Yagmur Summak ◽  
Sidar Bereketoglu ◽  
Inci Cevher Zeytin ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Broad Spectrum ◽  
In Silico ◽  
Antiviral Drug ◽  
In Silico Analysis ◽  
Cell Types ◽  
Suppressive Effect ◽  
Inhibitory Effect ◽  
Molecular Techniques

Ribavirin is a guanosine analog with broad-spectrum antiviral activity against RNA viruses. Based on this, we aimed to show the anti-SARS-CoV-2 activity of this drug molecule via in vitro, in silico, and molecular techniques. Ribavirin showed antiviral activity in Vero E6 cells following SARS-CoV-2 infection, whereas the drug itself did not show any toxic effect over the concentration range tested. In silico analysis suggested that ribavirin has a broad-spectrum impact on SARS-CoV-2, acting at different viral proteins. According to the detailed molecular techniques, ribavirin was shown to decrease the expression of TMPRSS2 at both mRNA and protein levels 48 h after treatment. The suppressive effect of ribavirin in ACE2 protein expression was shown to be dependent on cell types. Finally, proteolytic activity assays showed that ribavirin also showed an inhibitory effect on the TMPRSS2 enzyme. Based on these results, we hypothesized that ribavirin may inhibit the expression of TMPRSS2 by modulating the formation of inhibitory G-quadruplex structures at the TMPRSS2 promoter. As a conclusion, ribavirin is a potential antiviral drug for the treatment against SARS-CoV-2, and it interferes with the effects of TMPRSS2 and ACE2 expression.

scholarly journals In vitro Activity of Polyhydroxycarboxylates against Herpesviruses and Hiv

2001 ◽  
Vol 12 (6) ◽  
pp. 337-345 ◽  
Author(s):  
Astrid Meerbach ◽  
Johan Neyts ◽  
Jan Balzarini ◽  
Björn Helbig ◽  
Erik De Clercq ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Sexual Transmission ◽  
Close Correlation ◽  
Inhibitory Effect ◽  
Host Cells ◽  
Virus Adsorption ◽  
Carboxylic Groups ◽  
Simplex Virus ◽  
Hsv 1

The antiviral activity of 17 polyhydroxycarboxylates derived from phenolic compounds was evaluated against herpesviruses and HIV. When present during virus adsorption several of the polymers exhibited potent activity against herpes simplex virus type 1 (HSV-1), HSV-2, thymidine kinase deficient HSV-1, human cytomegalovirus (HCMV) and HIV-1 and HIV-2 at concentrations that were not toxic to the host cells. A close correlation was found between the 50% inhibitory concentrations of the polyhydroxycarboxylates against HCMV-induced cytopathicity, their inhibitory effect on the expression of HCMV-specific immediate early antigens and their inhibitory effects on HCMV adsorption to the cells. The antiviral activity of the phenolic polymers was dependent on the presence of a sufficient number of carboxylic groups. The mechanism of antiviral action of the polyhydroxycarboxylates can thus be ascribed to inhibition of virus adsorption. This type of compound may have potential in a vaginal gel to prevent sexual transmission of HSV and HIV.

scholarly journals Multiple Roles for BordetellaLipopolysaccharide Molecules during Respiratory Tract Infection

2000 ◽  
Vol 68 (12) ◽  
pp. 6720-6728 ◽  
Author(s):  
Eric T. Harvill ◽  
Andrew Preston ◽  
Peggy A. Cotter ◽  
Andrew G. Allen ◽  
Duncan J. Maskell ◽  
...  
Keyword(s):  
Tract Infection ◽  
Respiratory Tract ◽  
Respiratory Tract Infection ◽  
Adaptive Immunity ◽  
Lipid A ◽  
Core Oligosaccharide ◽  
O Antigen ◽  
Tract Infections

ABSTRACT Bordetella pertussis, Bordetella parapertussis, and Bordetella bronchiseptica are closely related subspecies that cause respiratory tract infections in humans and other mammals and express many similar virulence factors. Their lipopolysaccharide (LPS) molecules differ, containing either a complex trisaccharide (B. pertussis), a trisaccharide plus an O-antigen-like repeat (B. bronchiseptica), or an altered trisaccharide plus an O-antigen-like repeat (B. parapertussis). Deletion of the wlb locus results in the loss of membrane-distal polysaccharide domains in the three subspecies of bordetellae, leaving LPS molecules consisting of lipid A and core oligosaccharide. We have used wlb deletion (Δwlb) mutants to investigate the roles of distal LPS structures in respiratory tract infection by bordetellae. Each mutant was defective compared to its parent strain in colonization of the respiratory tracts of BALB/c mice, but the location in the respiratory tract and the time point at which defects were observed differed significantly. Although the Δwlb mutants were much more sensitive to complement-mediated killing in vitro, they displayed similar defects in respiratory tract colonization in C5−/− mice compared with wild-type (wt) mice, indicating that increased sensitivity to complement-mediated lysis is not sufficient to explain the in vivo defects. B. pertussis andB. parapertussis Δwlb mutants were also defective compared to wt strains in colonization of SCID-beige mice, indicating that the defects were not limited to interactions with adaptive immunity. Interestingly, the B. bronchiseptica Δwlbstrain was defective, compared to the wt strain, in colonization of the respiratory tracts of BALB/c mice beginning 1 week postinoculation but did not differ from the wt strain in its ability to colonize the respiratory tracts of B-cell- and T-cell-deficient mice, suggesting that wlb-dependent LPS modifications in B. bronchiseptica modulate interactions with adaptive immunity. These data show that biosynthesis of a full-length LPS molecule by these three bordetellae is essential for the expression of full virulence for mice. In addition, the data indicate that the different distal structures modifying the LPS molecules on these three closely related subspecies serve different purposes in respiratory tract infection, highlighting the diversity of functions attributable to LPS of gram-negative bacteria.

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