Griffithsin (GRFT) is a broad-spectrum antiviral protein that is effective against several glycosylated viruses. Here, we have evaluated the
in vitro
and
in vivo
antiviral activities of GRFT against ...Japanese encephalitis virus (JEV) infection.
In vitro
experiments showed that treatment of JEV with GRFT before inoculation of BHK-21 cells inhibited infection in a dose-dependent manner, with 99 % inhibition at 100 μg/ml and a 50 % inhibitory concentration
(
IC
50
) of 265 ng/ml (20 nM). Binding assays suggested that binding of GRFT to JEV virions inhibited JEV infection.
In vivo
experiment showed that GRFT (5 mg/kg) administered intraperitoneally before virus infection could completely prevent mortality in mice challenged intraperitoneally with a lethal dose of JEV. Our study also suggested that GRFT prevents JEV infection at the entry phase by targeting the virus. Collectively, our data demonstrate that GRFT is an antiviral agent with potential application in the development of therapeutics against JEV or other flavivirus infections.
•GRFT binds to the enveloped (E) and premature (prM) JEV glycoproteins.•Binding of GRFT to the JEV, competitively inhibited by mannose.•Pretreatment of GRFT with mannose, abolished its anti-JEV ...activity
Griffithsin (GRFT) is a broad-spectrum antiviral protein against several glycosylated viruses. In our previous publication, we have shown that GRFT exerted antiviral activity against Japanese encephalitis virus (JEV) infection. Herein, we further elucidated the mechanism by which GRFT inhibits JEV infection in BHK-21 cells. In vitro experiments using Pull-down assay and Co-immunoprecipitation (CO-IP) assay showed that GRFT binds to the JEV glycosylated viral proteins, specifically the enveloped (E) and premature (prM) glycoproteins. The binding of GRFT to the JEV was competitively inhibited by increasing concentrations of mannose; in turns abolished anti-JEV activity of GRFT. We suggested that, the binding of GRFT to the glycosylated viral proteins may contribute to its anti-JEV activity. Collectively, our data indicated a possible mechanism by which GRFT exerted its anti-JEV activity. This observation suggests GRFT's potentials in the development of therapeutics against JEV or other flavivirus infection.
Crimean-Congo haemorrhagic fever virus (CCHFV) is a tick-borne virus causing Crimean-Congo haemorrhagic fever (CCHF), a disease reported to have a high fatality rate in numerous countries. The virus ...is geographically widespread due to its vector, and numerous wild and domestic animals can develop asymptomatic infection. Serological and limited molecular evidence of CCHFV has previously been reported in
(the dromedary, or one-humped camel) in the United Arab Emirates (UAE). In this study, 238 camel samples were screened for CCHFV RNA where 16 camel samples were positive for CCHFV by RT-PCR. Analysis of full-length CCHFV genome sequences revealed a novel lineage in camels from the UAE, and potential reassortment of the M segment of the genome.
► Pokeweed antiviral protein (PAP) was expressed and purified from E. coli system. ► PAP suppressed JEV infection in vitro. ► The 50% inhibitory concentration (IC50) was 300ng/ml (23.1nM). ► PAP can ...decrease mortality in mice challenged with a lethal dose of JEV.
Pokeweed antiviral protein (PAP) is a plant-derived N-glycosidase ribosomal-inactivating protein isolated from Phytolacca americana. The antiviral activity of PAP has been described in several viruses. This study was to investigate the antiviral activity of PAP against Japanese encephalitis virus (JEV) infection in vitro and in vivo. Antiviral activity of PAP against JEV infection was evaluated in vitro using plaque forming assay, qRT-PCR and Western blot analysis. In vitro results showed that PAP inhibited replication of JEV in a dose-dependent manner with 50% inhibitory concentration (IC50) of 300ng/ml (23.1nM). Depurination assay suggested that the antiviral activity of PAP against JEV infection might be partially due to depurination of JEV genomic RNA. In vivo studies showed that PAP (1.0mg/kg) administered intraperitoneally decreased infection in mice challenged with a lethal dose of JEV, presenting a survival of 87.5% or 85.7% when administered pre-infection or post-infection. Collectively, our studies demonstrated that PAP possesses antiviral activity against JEV infection in vitro and in vivo, providing evidences for further development of PAP as an antiviral agent against JEV infection.
Mycoplasma hyorhinis is an opportunistic pathogen of pigs. Recently, it has been shown to transform cell cultures, increasing the attention of the researchers. Studies on the pathogenesis require ...specific genetic tool that is not yet available for the pathogen. To address this limitation, we constructed two suicide plasmids pGEMT-tetM/LR and pGEMT-recA-tetM/LR having a tetracycline resistance marker flanked by two hemolysin gene arms. The latter plasmid encodes an E. coli recA, a gene involved in DNA recombination, repair and maintenance of DNA. Using inactivation of the hemolysin gene, which results in a detectable and measurable phenotype, we found that each plasmid can disrupt the hemolysin gene of M. hyorhinis through a double cross-over homologous recombination. However, inclusion of the E. coli recA gene in the construct resulted in 9-fold increase in the frequency of hemolysin gene mutants among the screened tetracycline resistance colonies. The resultant hemolysin mutant strain lacks the ability to lyse mouse bed blood cells (RBC) when tested in vitro (p<0.001). The host-plasmid system described in this study, has applications for the genetic manipulation of this pathogen and potentially other mycoplasmas.
•The pGEMT-tetM/LR and pGEMT-recA-tetM/LR suicide vectors have been constructed.•These vectors were used to disrupt Hemolysin gene by inserting the tetM gene at the hemolysin site.•Inclusion of recA gene in the constructs improved the gene targeting efficiency.•Hemolysin mutants have diminished ability to lyse mouse erythrocytes.
Mycoplasma hyorhinis (M. hyorhinis) is an opportunistic pig pathogen, belonging to the class Mollicutes. It causes polyserositis, arthritis and cancers in vitro, increasing attention of the ...researchers. Currently, there is no available genetic tool to manipulate its genome. This study describes a development of oriC-plasmids harboring either large (pGEMT-LoriC) or minimum (pGEMT-MoriC) origin of replication (oriC) of M. hyorhinis along with tetracycline resistance marker.These plasmids were successfully transformed into M. hyorhinis with average transformation frequency of 1.5 × 10
and 2.0 × 10
transformants/CFU for pGEMT-LoriC and pGEMT-MoriC respectively, and were integrated at the chromosomal oriC as well as remained freely replicating. We also constructed a Mini-oriC-HT1 targeting plasmid by inclusion of hlyC arms and was used to inactivate hlyC at average frequency of 50%. The efficiency of hlyC inactivation was further improved (by 90%) when Mini-oriC-HT2 that contains E. coli recA was used. In both cases, hemolysin mutant bacteria diminished the ability to lyse mouse RBCs compared to wild-type (P < 0.001). OriC-plasmids described in this study may, therefore open the way for functional genomics in M. hyorhinis. Furthermore, this is a first study demonstrated the gene associated with a hemolytic phenotype in mycoplasmas.
Mycoplasma hyorhinis
(
M. hyorhinis
) is an opportunistic pathogen of pigs and has been shown to transform cell cultures, which has increased the interest of researchers. The green florescence ...proteins (
GFP
) gene of
Aquorea victoria
, proved to be a vital marker to identify transformed cells in mixed populations. Use of
GFP
to observe gene transfer and expression in
M. hyorhinis
(strain HUB-1) has not been described. We have constructed a pMD18-O/MHRgfp plasmid containing the
p97
gene promoter, origin of replication, tetracycline resistance marker and
GFP
gene controlled by the
p97
gene promoter. The plasmid transformed into
M. hyorhinis
with a frequency of ~4 × 10
−3
cfu/µg plasmid DNA and could be detected by PCR amplification of the
GFP
gene from the total DNA of the transformant mycoplasmas. Analysis of a single clone grown on KM2-Agar containing tetracycline, showed a green fluorescence color. Conclusively, this report suggests the usefulness of
GFP
to monitor transient gene transfer and expression in
M. hyorhinis,
eventually minimizing screening procedures for gene transfer and expression.
Mycoplasma hyopneumoniae (M. hyopneumoniae) infection affects the swine industry. Lithium chloride (LiCl), is a drug used to treat bipolar disorder and has also shown activity against bacterial and ...viral infections. Herein, we evaluated the antibacterial activity of LiCl on PK-15 cells infected with M. hyopneumoniae. Incubation of LiCl (40mM) with cells for 24h, did not significantly affect the cell viability. The qRT–PCR showed ~80% reduction in M. hyopneumoniae genome when LiCl added post-infection. A direct effect of LiCl on bacteria was also observed. However, treatment of cells with LiCl prior infection, does not protect against the infection. Anti-bacterial activity of LiCl was further confirmed by IFA, which demonstrated a reduction in the bacterial protein. With 40mM LiCI, the apoptotic cell death, production of nitric oxide and superoxide anion induced by M. hyopneumoniae, were prevented by ~80%, 60% and 58% respectively. Moreover, caspase-3 activity was also reduced (82%) in cells treated with 40mM LiCl. LiCl showed activity against various strains of M. hyopneumoniae examined in our study. Collectively, our data showed that LiCl inhibited the infection of M. hyopneumoniae through anti-apoptotic mechanism.
•LiCl inhibits Mycoplasma hyopneumoniae infection in PK-15 cells dose-dependent manner.•LiCl inhibits 80% of apoptosis induced M. hyopneumoniae infection in PK-15 cells.•LiCl protects against the infection of various strains of M. hyopneumoniae infected PK-15 cells.
The objective of this study was to develop a TaqMan probe-based, sensitive, specific duplex real-time PCR assay for simultaneous detection of Mycoplasma hyopneumoniae and Mycoplasma hyorhinis. The ...specific primers and probes, labeled with FAM and Texas Red, respectively, were designed to amplify the p97 gene of M. hyopneumoniae and p37gene of M. hyorhinis. The duplex real-time PCR reaction mixtures were established and optimized and the sensitivity, specificity and reproducibility of the assay were assessed. The sensitivity of the duplex real-time PCR was found to be 10 copies/μL for both M. hyopneumoniae and M. hyorhinis, respectively. There was no cross reaction with other common viral and bacterial pathogens. The concentration of standard coefficient of variation of Ct values was less than 5%, indicating a good reproducibility. Clinical samples (n = 937) were tested by the duplex real-time PCR assay, including broncho-alveolar lavage fluids, nasal swabs, tissues and cell culture supernatant. Duplex real-time PCR for simultaneous detection of M. hyopneumoniae and M. hyorhinis was highly sensitive and can be utilized for diagnosing clinical samples. It is timeefficient and economic, thereby providing a new approach to control both M. hyopneumoniae and M. hyorhinis.
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