Displaying publications 101 - 120 of 204 in total

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  1. Fulltext Erythrocyte-binding assays reveal higher binding of Plasmodium knowlesi Duffy binding protein to human Fya+/b+ erythrocytes than to Fya+/b- erythrocytes
    Fong MY, Cheong FW, Lau YL
    Parasit Vectors, 2018 Sep 26;11(1):527.
    PMID: 30257710 DOI: 10.1186/s13071-018-3118-8
    BACKGROUND: The merozoite of the zoonotic Plasmodium knowlesi invades human erythrocytes via the binding of its Duffy binding protein (PkDBPαII) to the Duffy antigen on the eythrocytes. The Duffy antigen has two immunologically distinct forms, Fya and Fyb. In this study, the erythrocyte-binding assay was used to quantitatively determine and compare the binding level of PkDBPαII to Fya+/b+ and Fya+/b- human erythrocytes.

    RESULTS: In the erythrocyte-binding assay, binding level was determined by scoring the number of rosettes that were formed by erythrocytes surrounding transfected mammalian COS-7 cells which expressed PkDBPαII. The assay result revealed a significant difference in the binding level. The number of rosettes scored for Fya+/b+ was 1.64-fold higher than that of Fya+/b- (155.50 ± 34.32 and 94.75 ± 23.16 rosettes, respectively; t(6) = -2.935, P = 0.026).

    CONCLUSIONS: The erythrocyte-binding assay provided a simple approach to quantitatively determine the binding level of PkDBPαII to the erythrocyte Duffy antigen. Using this assay, PkDBPαII was found to display higher binding to Fya+/b+ erythrocytes than to Fya+/b- erythrocytes.

    Matched MeSH terms: Cercopithecus aethiops
  2. Fulltext Functional Genomics and Immunologic Tools: The Impact of Viral and Host Genetic Variations on the Outcome of Zika Virus Infection
    Yun SI, Song BH, Frank JC, Julander JG, Olsen AL, Polejaeva IA, et al.
    Viruses, 2018 08 11;10(8).
    PMID: 30103523 DOI: 10.3390/v10080422
    Zika virus (ZIKV) causes no-to-mild symptoms or severe neurological disorders. To investigate the importance of viral and host genetic variations in determining ZIKV infection outcomes, we created three full-length infectious cDNA clones as bacterial artificial chromosomes for each of three spatiotemporally distinct and genetically divergent ZIKVs: MR-766 (Uganda, 1947), P6-740 (Malaysia, 1966), and PRVABC-59 (Puerto Rico, 2015). Using the three molecularly cloned ZIKVs, together with 13 ZIKV region-specific polyclonal antibodies covering nearly the entire viral protein-coding region, we made three conceptual advances: (i) We created a comprehensive genome-wide portrait of ZIKV gene products and their related species, with several previously undescribed gene products identified in the case of all three molecularly cloned ZIKVs. (ii) We found that ZIKV has a broad cell tropism in vitro, being capable of establishing productive infection in 16 of 17 animal cell lines from 12 different species, although its growth kinetics varied depending on both the specific virus strain and host cell line. More importantly, we identified one ZIKV-non-susceptible bovine cell line that has a block in viral entry but fully supports the subsequent post-entry steps. (iii) We showed that in mice, the three molecularly cloned ZIKVs differ in their neuropathogenicity, depending on the particular combination of viral and host genetic backgrounds, as well as in the presence or absence of type I/II interferon signaling. Overall, our findings demonstrate the impact of viral and host genetic variations on the replication kinetics and neuropathogenicity of ZIKV and provide multiple avenues for developing and testing medical countermeasures against ZIKV.
    Matched MeSH terms: Cercopithecus aethiops
  3. Identification of strain diversity and phylogenetic analysis based on two major essential proteins of Orf viruses isolated from several clinical cases reported in Malaysia
    Bala JA, Balakrishnan KN, Jesse FFA, Abdullah AA, Noorzahari MSB, Ghazali MT, et al.
    Infect Genet Evol, 2020 01;77:104076.
    PMID: 31678648 DOI: 10.1016/j.meegid.2019.104076
    There is a little information on the characterization of Orf virus strains that are endemic in Malaysia. The relationship between the severity of disease and the molecular genetic profile of Orf virus strains has not been fully elucidated. This study documented the first confirmed report of contagious ecthyma causing by Orf virus in goats from a selected state of eastern peninsular Malaysia. The disease causes significant debilitation due to the inability of affected animals to suckle which brings a great economic loss to the farmers. A total of 504 animals were examined individually to recognize the affected animals with Orf lesion. Skin scrapping was used to collect the scab material from the infected animals. The presence of Orf virus was confirmed by combination of methods including virus isolation on vero cells, identification by Transmission Electron Microscopy (TEM) and molecular technique using PCR and Sanger sequencing. The results showed the successful isolation of four Orf virus strains with a typical cytopathic effects on the cultured vero cells line. The morphology was confirmed to be Orf virus with a distinctive ovoid and criss cross structure. The phylogenetic analysis revealed that these isolated strains were closely related to each other and to other previously isolated Malaysian orf viruses. In addition these Orf virus strains were closely related to Orf viruses from China and India. This study provides more valuable insight in terms of genotype of Orf virus circulating in Malaysia.
    Matched MeSH terms: Cercopithecus aethiops
  4. Evaluation of the in vitro antileishmanial activities of bioactive guided fractionations of two medicinal plants
    Al Nasr IS
    Trop Biomed, 2020 Mar 01;37(1):15-23.
    PMID: 33612714
    The organisms of the genus Leishmania are flagellated protozoan parasites and are the causative agents of leishmaniasis. This disease is a major health problem, especially in tropical countries. Currently, cutaneous leishmaniasis is treated by chemotherapy using pentavalent antimonials, but these drugs have serious organo-toxicity, drug resistance on several occasions, and low efficiency in controlling the infection. The present work is carried out to evaluate the in vitro antileishmanial activity of methanolic extracts and phytochemical fractions of two plants ethnobotanically used against leishmaniasis and skin infection, Calotropis procera and Rhazya stricta leaves against Leishmania major promastigote and amastigote stages and cytotoxicity against the Vero cell line. The leaves of C. procera and R. stricta were extracted with methanol and fractionated by petroleum ether, chloroform, ethyl acetate, n-butanol, and water. The methanolic extracts of the leaves of C. procera and R. stricta exhibited antileishmanial activity against L. major promastigotes with IC50 values of 66.8 and 42.4 µg mL-1, respectively. While their CC50 2.3 and 298 µg mL-1 and their SI 0.03 and 7.03 respectively. However, the fractionations of the methanolic extract of C. procera leaves revealed antiparasitic activity against both L. major promastigote and amastigote stages in vitro, which significantly increased with polarity with the exception of n-butanol. Hence the best activity was revealed by the water fraction (IC50 of 26.3 and 29.0 µg mL-1) for the two stages. In conclusion, further phytochemical investigation should be performed for the C. procera water extract in terms of antileishmanial active ingredient isolation that may enhance the possibility of avoiding toxic substances and overcome the low SI (1.1 and 1.01).
    Matched MeSH terms: Cercopithecus aethiops
  5. Fulltext Antiviral activity of silymarin and baicalein against dengue virus
    Low ZX, OuYong BM, Hassandarvish P, Poh CL, Ramanathan B
    Sci Rep, 2021 10 27;11(1):21221.
    PMID: 34707245 DOI: 10.1038/s41598-021-98949-y
    Dengue is an arthropod-borne viral disease that has become endemic and a global threat in many countries with no effective antiviral drug available currently. This study showed that flavonoids: silymarin and baicalein could inhibit the dengue virus in vitro and were well tolerated in Vero cells with a half-maximum cytotoxic concentration (CC50) of 749.70 µg/mL and 271.03 µg/mL, respectively. Silymarin and baicalein exerted virucidal effects against DENV-3, with a selective index (SI) of 10.87 and 21.34, respectively. Baicalein showed a better inhibition of intracellular DENV-3 progeny with a SI of 7.82 compared to silymarin. Baicalein effectively blocked DENV-3 attachment (95.59%) to the Vero cells, while silymarin prevented the viral entry (72.46%) into the cells, thus reducing viral infectivity. Both flavonoids showed promising antiviral activity against all four dengue serotypes. The in silico molecular docking showed that silymarin could bind to the viral envelope (E) protein with a binding affinity of - 8.5 kcal/mol and form hydrogen bonds with the amino acids GLN120, TRP229, ASN89, and THR223 of the E protein. Overall, this study showed that silymarin and baicalein exhibited potential anti-DENV activity and could serve as promising antiviral agents for further development against dengue infection.
    Matched MeSH terms: Cercopithecus aethiops
  6. Antifungal and cytotoxic activities of selected medicinal plants from Malaysia
    Chan YS, Cheah YH, Chong PZ, Khor HL, Teh WS, Khoo KS, et al.
    Pak J Pharm Sci, 2018 Jan;31(1):119-127.
    PMID: 29348093
    This study was conducted to investigate the antifungal potential and cytotoxicity of selected medicinal plants from Malaysia. The extracts from the stem of Cissus quadrangularis and the leaves of Asplenium nidus, Pereskia bleo, Persicaria odorata and Sauropus androgynus were assayed against six fungi using p-iodonitrotetrazolium-based on colorimetric broth microdilution method. All the plant extracts were found to be fungicidal against at least one type of fungus. The strongest fungicidal activity (minimum fungicidal concentration=0.16 mg/mL) were exhibited by the hexane extract of C. quadrangularis, the hexane, chloroform, ethanol and methanol extracts of P. bleo, the hexane and ethyl acetate extracts of P. odorata, and the water extract of A. nidus. In terms of cytotoxicity on the African monkey kidney epithelial (Vero) cells, the chloroform extract of P. odorata produced the lowest 50% cytotoxic concentration (100.3 ± 4.2 μ g/mL). In contrast, none of the water extracts from the studied plants caused significant toxicity on the cells. The water extract of A. nidus warrants further investigation since it showed the strongest fungicidal activity and the highest total activity (179.22 L/g) against Issatchenkia orientalis, and did not cause any toxicity to the Vero cells.
    Matched MeSH terms: Cercopithecus aethiops
  7. A previously unknown reovirus of bat origin is associated with an acute respiratory disease in humans
    Chua KB, Crameri G, Hyatt A, Yu M, Tompang MR, Rosli J, et al.
    Proc Natl Acad Sci U S A, 2007 Jul 03;104(27):11424-9.
    PMID: 17592121
    Respiratory infections constitute the most widespread human infectious disease, and a substantial proportion of them are caused by unknown etiological agents. Reoviruses (respiratory enteric orphan viruses) were first isolated from humans in the early 1950s and so named because they were not associated with any known disease. Here, we report a previously unknown reovirus (named "Melaka virus") isolated from a 39-year-old male patient in Melaka, Malaysia, who was suffering from high fever and acute respiratory disease at the time of virus isolation. Two of his family members developed similar symptoms approximately 1 week later and had serological evidence of infection with the same virus. Epidemiological tracing revealed that the family was exposed to a bat in the house approximately 1 week before the onset of the father's clinical symptoms. Genome sequence analysis indicated a close genetic relationship between Melaka virus and Pulau virus, a reovirus isolated in 1999 from fruit bats in Tioman Island, Malaysia. Screening of sera collected from human volunteers on the island revealed that 14 of 109 (13%) were positive for both Pulau and Melaka viruses. This is the first report of an orthoreovirus in association with acute human respiratory diseases. Melaka virus is serologically not related to the different types of mammalian reoviruses that were known to infect humans asymptomatically. These data indicate that bat-borne reoviruses can be transmitted to and cause clinical diseases in humans.
    Matched MeSH terms: Cercopithecus aethiops
  8. Establishment of a Nipah virus rescue system
    Yoneda M, Guillaume V, Ikeda F, Sakuma Y, Sato H, Wild TF, et al.
    Proc Natl Acad Sci U S A, 2006 Oct 31;103(44):16508-13.
    PMID: 17053073
    Nipah virus (NiV), a paramyxovirus, was first discovered in Malaysia in 1998 in an outbreak of infection in pigs and humans and incurred a high fatality rate in humans. Fruit bats, living in vast areas extending from India to the western Pacific, were identified as the natural reservoir of the virus. However, the mechanisms that resulted in severe pathogenicity in humans (up to 70% mortality) and that enabled crossing the species barrier were not known. In this study, we established a system that enabled the rescue of replicating NiVs from a cloned DNA by cotransfection of a constructed full-length cDNA clone and supporting plasmids coding virus nucleoprotein, phosphoprotein, and polymerase with the infection of the recombinant vaccinia virus, MVAGKT7, expressing T7 RNA polymerase. The rescued NiV (rNiV), by using the newly developed reverse genetics system, showed properties in vitro that were similar to the parent virus and retained the severe pathogenicity in a previously established animal model by experimental infection. A recombinant NiV was also developed, expressing enhanced green fluorescent protein (rNiV-EGFP). Using the virus, permissibility of NiV was compared with the presence of a known cellular receptor, ephrin B2, in a number of cell lines of different origins. Interestingly, two cell lines expressing ephrin B2 were not susceptible for rNiV-EGFP, indicating that additional factors are clearly required for full NiV replication. The reverse genetics for NiV will provide a powerful tool for the analysis of the molecular mechanisms of pathogenicity and cross-species infection.
    Matched MeSH terms: Cercopithecus aethiops
  9. Fulltext Virucidal activity of Garcinia parvifolia leaf extracts in animal cell culture
    Adnan A, Allaudin ZN, Hani H, Loh HS, Khoo TJ, Ting KN, et al.
    BMC Complement Altern Med, 2019 Jul 10;19(1):169.
    PMID: 31291936 DOI: 10.1186/s12906-019-2586-5
    BACKGROUND: Garcinia species contain bioactive compounds such as flavonoids, xanthones, triterpernoids, and benzophenones with antibacterial, antifungal, anti-inflammatory, and antioxidant activities. In addition, many of these compounds show interesting biological properties such as anti-human immunodeficiency virus activity. Garcinia parvifolia is used in traditional medicine. Currently, the antiviral activity of G. parvifolia is not known.

    METHODS: This study was conducted to determine the effects of ethyl acetate (45 L Ea), ethanol (45 L Et), and hexane (45 L H) leaf extracts of G. parvifolia on the infectivity of pseudorabies virus (PrV) in Vero cells. The antiviral effects of the extracts were determined by cytopathic effect (CPE), inhibition, attachment, and virucidal assays.

    RESULTS: The 50% cytotoxicity concentration (CC50) values obtained were 237.5, 555.0, and 

    Matched MeSH terms: Cercopithecus aethiops
  10. Assessment of Euphorbia retusa and Pulicaria undulata activity against Leishmania major and Toxoplasma gondii
    Khan TA, Al Nasr IS, Mujawah AH, Koko WS
    Trop Biomed, 2021 Mar 01;38(1):135-141.
    PMID: 33797536 DOI: 10.47665/tb.38.1.023
    Leishmaniasis and toxoplasmosis are parasitic protozoal diseases that pose serious health concerns, especially for immunocompromised people. Leishmania major and Toxoplasma gondii are endemic in Saudi Arabia and are particularly common in the Qassim Region. The present work was conducted to evaluate the in vitro antileishmanial and antitoxoplasmal activity of methanolic extracts and phytochemical fractions from two plants, Euphorpia retusa and Pulicaria undulata, which are ethnobotanical agents used to treat parasitic infection. Whole E. retusa and P. undulata plants were extracted with methanol and fractionated using petroleum ether, chloroform, ethyl acetate, n-butanol, and water and then were tested in vitro against L. major promastigote and the amastigote stages of T. gondii; the cytotoxicity of the extracts was tested against Vero cell line. The methanolic extracts of E. retusa and P. undulata exhibited promising antitoxoplasmal activity against T. gondii with EC50 values 5.6 and 12.7 μg mL-1, respectively. The chloroform fraction of P. undulata was the most potent, exhibiting an EC50 of 1.4 μg mL-1 and SI value of 12.1. It was also the most active fraction against both L. major promastigotes and amastigotes, exhibiting an EC50 of 3.9 and 3.8 μg mL-1 and SI values 4.4 and 4.5, respectively. The chloroform fraction from P. undulata is a very good candidate for the isolation of active antitoxoplasmal and antileishmanial ingredients; therefore, further phytochemical analysis for active compound isolation is highly recommended.
    Matched MeSH terms: Cercopithecus aethiops
  11. Fulltext Biosynthesis of zinc oxide nanoparticles by cell-biomass and supernatant of Lactobacillus plantarum TA4 and its antibacterial and biocompatibility properties
    Mohd Yusof H, Abdul Rahman N, Mohamad R, Zaidan UH, Samsudin AA
    Sci Rep, 2020 Nov 17;10(1):19996.
    PMID: 33204003 DOI: 10.1038/s41598-020-76402-w
    This study aims to utilize the cell-biomass (CB) and supernatant (CFS) of zinc-tolerant Lactobacillus plantarum TA4 as a prospective nanofactory to synthesize ZnO NPs. The surface plasmon resonance for the biosynthesized ZnO NPs-CFS and ZnO NPs-CB was 349 nm and 351 nm, respectively, thereby confirming the formation of ZnO NPs. The FTIR analysis revealed the presence of proteins, carboxyl, and hydroxyl groups on the surfaces of both the biosynthesized ZnO NPs that act as reducing and stabilizing agents. The DLS analysis revealed that the poly-dispersity indexes was less than 0.4 for both ZnO NPs. In addition, the HR-TEM micrographs of the biosynthesized ZnO NPs revealed a flower-like pattern for ZnO NPs-CFS and an irregular shape for ZnO NPs-CB with particles size of 291.1 and 191.8 nm, respectively. In this study, the biosynthesized ZnO NPs exhibited antibacterial activity against pathogenic bacteria in a concentration-dependent manner and showed biocompatibility with the Vero cell line at specific concentrations. Overall, CFS and CB of L. plantarum TA4 can potentially be used as a nanofactory for the biological synthesis of ZnO NPs.
    Matched MeSH terms: Cercopithecus aethiops
  12. Fulltext Gene transfer into the lung by nanoparticle dextran-spermine/plasmid DNA complexes
    Abdullah S, Wendy-Yeo WY, Hosseinkhani H, Hosseinkhani M, Masrawa E, Ramasamy R, et al.
    J Biomed Biotechnol, 2010;2010:284840.
    PMID: 20617146 DOI: 10.1155/2010/284840
    A novel cationic polymer, dextran-spermine (D-SPM), has been found to mediate gene expression in a wide variety of cell lines and in vivo through systemic delivery. Here, we extended the observations by determining the optimal conditions for gene expression of D-SPM/plasmid DNA (D-SPM/pDNA) in cell lines and in the lungs of BALB/c mice via instillation delivery. In vitro studies showed that D-SPM could partially protect pDNA from degradation by nuclease and exhibited optimal gene transfer efficiency at D-SPM to pDNA weight-mixing ratio of 12. In the lungs of mice, the levels of gene expression generated by D-SPM/pDNA are highly dependent on the weight-mixing ratio of D-SPM to pDNA, amount of pDNA in the complex, and the assay time postdelivery. Readministration of the complex at day 1 following the first dosing showed no significant effect on the retention and duration of gene expression. The study also showed that there was a clear trend of increasing size of the complexes as the amount of pDNA was increased, where the sizes of the D-SPM/pDNA complexes were within the nanometer range.
    Matched MeSH terms: Cercopithecus aethiops
  13. A rapid immune plaque assay for the detection of Hendra and Nipah viruses and anti-virus antibodies
    Crameri G, Wang LF, Morrissy C, White J, Eaton BT
    J Virol Methods, 2002 Jan;99(1-2):41-51.
    PMID: 11684302
    Rapid immune plaque assays have been developed to quantify biohazard level 4 agents Hendra and Nipah viruses and detect neutralising antibodies to both viruses. The methods rely on the fact that both viruses rapidly generate large syncytia in monolayers of Vero cells within 24 h and that monospecific antiserum to the Hendra virus phosphoprotein (P) detects that protein in both Hendra and Nipah virus-induced syncytia after methanol fixation of virus-infected cells. The P protein is a constituent of the ribonucleoprotein core of the viruses and a component of the viral RNA-dependent RNA polymerase and is made in significant amounts in infected cells. In the immune plaque assay, anti-P antibody is localised by an alkaline phosphatase-linked second antibody and the Western blot substrates 5-bromo-4-chloro-3-indolyl phosphate and p-nitro blue tetrazolium. A modification of the rapid immune plaque assay was also used to detect antibodies to Nipah virus in a panel of porcine field sera from Malaysia and the results showed good agreement between the immune plaque assay and a traditional serum neutralisation test. After methanol fixation, plates can be stored for up to 7 months and may be used in the immune plaque assay to complement the enzyme-linked immunosorbent assay screening of sera for antibodies to Nipah virus. At present, all enzyme-linked immunosorbent assay positive sera are subject to confirmatory serum neutralisation tests. Use of the immune plaque assay may reduce the number of sera requiring confirmatory neutralisation testing for Nipah virus antibodies under biohazard level 4 conditions by identifying those that generate false positive in the enzyme-linked immunosorbent assay.
    Matched MeSH terms: Cercopithecus aethiops
  14. Capture of cell culture-derived influenza virus by lectins: strain independent, but host cell dependent
    Opitz L, Zimmermann A, Lehmann S, Genzel Y, Lübben H, Reichl U, et al.
    J Virol Methods, 2008 Dec;154(1-2):61-8.
    PMID: 18840469 DOI: 10.1016/j.jviromet.2008.09.004
    Strategies to control influenza outbreaks are focused mainly on prophylactic vaccination. Human influenza vaccines are trivalent blends of different virus subtypes. Therefore and due to frequent antigenic drifts, strain independent manufacturing processes are required for vaccine production. This study verifies the strain independency of a capture method based on Euonymus europaeus lectin-affinity chromatography (EEL-AC) for downstream processing of influenza viruses under various culture conditions propagated in MDCK cells. A comprehensive lectin binding screening was conducted for two influenza virus types from the season 2007/2008 (A/Wisconsin/67/2005, B/Malaysia/2506/2004) including a comparison of virus-lectin interaction by surface plasmon resonance technology. EEL-AC resulted in a reproducible high product recovery rate and a high degree of contaminant removal in the case of both MDCK cell-derived influenza virus types demonstrating clearly the general applicability of EEL-AC. In addition, host cell dependency of EEL-AC was studied with two industrial relevant cell lines: Vero and MDCK cells. However, the choice of the host cell lines is known to lead to different product glycosylation profiles. Hence, altered lectin specificities have been observed between the two cell lines, requiring process adaptations between different influenza vaccine production systems.
    Matched MeSH terms: Cercopithecus aethiops
  15. Fulltext Enterovirus 71 outbreak, Brunei
    AbuBakar S, Sam IC, Yusof J, Lim MK, Misbah S, MatRahim N, et al.
    Emerg Infect Dis, 2009 Jan;15(1):79-82.
    PMID: 19116058 DOI: 10.3201/eid1501.080264
    Enterovirus 71 (EV71) outbreaks occur periodically in the Asia-Pacific region. In 2006, Brunei reported its first major outbreak of EV71 infections, associated with fatalities from neurologic complications. Isolated EV71 strains formed a distinct lineage with low diversity within subgenogroup B5, suggesting recent introduction and rapid spread within Brunei.
    Matched MeSH terms: Cercopithecus aethiops
  16. Fulltext Baicalin, a metabolite of baicalein with antiviral activity against dengue virus
    Moghaddam E, Teoh BT, Sam SS, Lani R, Hassandarvish P, Chik Z, et al.
    Sci Rep, 2014 Jun 26;4:5452.
    PMID: 24965553 DOI: 10.1038/srep05452
    Baicalin, a flavonoid derived from Scutellaria baicalensis, is the main metabolite of baicalein released following administration in different animal models and human. We previously reported the antiviral activity of baicalein against dengue virus (DENV). Here, we examined the anti-DENV properties of baicalin in vitro, and described the inhibitory potentials of baicalin at different steps of DENV-2 (NGC strain) replication. Our in vitro antiviral experiments showed that baicalin inhibited virus replication at IC50 = 13.5 ± 0.08 μg/ml with SI = 21.5 following virus internalization by Vero cells. Baicalin exhibited virucidal activity against DENV-2 extracellular particles at IC50 = 8.74 ± 0.08 μg/ml and showed anti-adsorption effect with IC50 = 18.07 ± 0.2 μg/ml. Our findings showed that baicalin as the main metabolite of baicalein exerting in vitro anti-DENV activity. Further investigations on baicalein and baicalin to deduce its antiviral therapeutic effects are warranted.
    Matched MeSH terms: Cercopithecus aethiops
  17. Fulltext The Nature of Exposure Drives Transmission of Nipah Viruses from Malaysia and Bangladesh in Ferrets
    Clayton BA, Middleton D, Arkinstall R, Frazer L, Wang LF, Marsh GA
    PLoS Negl Trop Dis, 2016 06;10(6):e0004775.
    PMID: 27341030 DOI: 10.1371/journal.pntd.0004775
    Person-to-person transmission is a key feature of human Nipah virus outbreaks in Bangladesh. In contrast, in an outbreak of Nipah virus in Malaysia, people acquired infections from pigs. It is not known whether this important epidemiological difference is driven primarily by differences between NiV Bangladesh (NiV-BD) and Malaysia (NiV-MY) at a virus level, or by environmental or host factors. In a time course study, ferrets were oronasally exposed to equivalent doses of NiV-BD or NiV-MY. More rapid onset of productive infection and higher levels of virus replication in respiratory tract tissues were seen for NiV-BD compared to NiV-MY, corroborating our previous report of increased oral shedding of NiV-BD in ferrets and suggesting a contributory mechanism for increased NiV-BD transmission between people compared to NiV-MY. However, we recognize that transmission occurs within a social and environmental framework that may have an important and differentiating role in NiV transmission rates. With this in mind, ferret-to-ferret transmission of NiV-BD and NiV-MY was assessed under differing viral exposure conditions. Transmission was not identified for either virus when naïve ferrets were cohoused with experimentally-infected animals. In contrast, all naïve ferrets developed acute infection following assisted and direct exposure to oronasal fluid from animals that were shedding either NiV-BD or NiV-MY. Our findings for ferrets indicate that, although NiV-BD may be shed at higher levels than NiV-MY, transmission risk may be equivalently low under exposure conditions provided by cohabitation alone. In contrast, active transfer of infected bodily fluids consistently results in transmission, regardless of the virus strain. These observations suggest that the risk of NiV transmission is underpinned by social and environmental factors, and will have practical implications for managing transmission risk during outbreaks of human disease.
    Matched MeSH terms: Cercopithecus aethiops
  18. Synthesis, structure, DNA/BSA interaction and in vitro cytotoxic activity of nickel(II) complexes derived from S-allyldithiocarbazate
    Nanjundan N, Selvakumar P, Narayanasamy R, Haque RA, Velmurugan K, Nandhakumar R, et al.
    J. Photochem. Photobiol. B, Biol., 2014 Dec;141:176-85.
    PMID: 25463665 DOI: 10.1016/j.jphotobiol.2014.10.009
    Two nickel(II) complexes with formula NiL1 and NiL2 (HL1 = S-allyl-4-methoxybenzylidene hydrazinecarbodithioate, HL2 = S-allyl-1-napthylidenehydrazinecarbodithioate) have been synthesized and characterized by elemental analysis, FT-IR, NMR, UV-vis spectroscopy and ESI mass spectrometry. The crystal structure of complex 1 has been determined by single crystal X-ray diffractometry. Both HL1 and HL2 ligands are coordinated to the metal in thiolate form. In complexes, squareplanar geometry of the nickel is coordinated with two bidentate ligand units acting through azomethine nitrogen and thiolato sulfur atoms. To explore the potential medicinal value of the complexes with calf thymus DNA and bovine serum albumin (BSA) were studied at normal physiological conditions using fluorescence spectral techniques. The DNA binding constant values of the complexes were found in the range from 5.02 × 10(4), 3.54 × 10(4), and the binding affinities are in the following order 1 > 2. In addition, nickel complexes 1 and 2 shows better binding propensity to the bovine serum albumin (BSA) protein, giving a Ksv value 5.8 × 10(4), 4.47 × 10(4) respectively. From the oxidative cleavage of the complexes with pBR322 DNA, it is inferred that the effects of cleavage are dose-dependent. In addition, in vitro cytotoxicity of the complexes assayed against Vero and HeLa cell lines have shown higher cytotoxic activity with the lower IC50 values indicating their efficiency in killing cancer cells even at various concentrations.
    Matched MeSH terms: Cercopithecus aethiops
  19. Fulltext Single-dose live-attenuated Nipah virus vaccines confer complete protection by eliciting antibodies directed against surface glycoproteins
    DeBuysscher BL, Scott D, Marzi A, Prescott J, Feldmann H
    Vaccine, 2014 May 07;32(22):2637-44.
    PMID: 24631094 DOI: 10.1016/j.vaccine.2014.02.087
    BACKGROUND: Nipah virus (NiV), a zoonotic pathogen causing severe respiratory illness and encephalitis in humans, emerged in Malaysia in 1998 with subsequent outbreaks on an almost annual basis since 2001 in parts of the Indian subcontinent. The high case fatality rate, human-to-human transmission, wide-ranging reservoir distribution and lack of licensed intervention options are making NiV a serious regional and potential global public health problem. The objective of this study was to develop a fast-acting, single-dose NiV vaccine that could be implemented in a ring vaccination approach during outbreaks.

    METHODS: In this study we have designed new live-attenuated vaccine vectors based on recombinant vesicular stomatitis viruses (rVSV) expressing NiV glycoproteins (G or F) or nucleoprotein (N) and evaluated their protective efficacy in Syrian hamsters, an established NiV animal disease model. We further characterized the humoral immune response to vaccination in hamsters using ELISA and neutralization assays and performed serum transfer studies.

    RESULTS: Vaccination of Syrian hamsters with a single dose of the rVSV vaccine vectors resulted in strong humoral immune responses with neutralizing activities found only in those animals vaccinated with rVSV expressing NiV G or F proteins. Vaccinated animals with neutralizing antibody responses were completely protected from lethal NiV disease, whereas animals vaccinated with rVSV expressing NiV N showed only partial protection. Protection of NiV G or F vaccinated animals was conferred by antibodies, most likely the neutralizing fraction, as demonstrated by serum transfer studies. Protection of N-vaccinated hamsters was not antibody-dependent indicating a role of adaptive cellular responses for protection.

    CONCLUSIONS: The rVSV vectors expressing Nipah virus G or F are prime candidates for new 'emergency vaccines' to be utilized for NiV outbreak management.

    Matched MeSH terms: Cercopithecus aethiops
  20. Fulltext Evaluation of antiviral activities of four local Malaysian Phyllanthus species against herpes simplex viruses and possible antiviral target
    Tan WC, Jaganath IB, Manikam R, Sekaran SD
    Int J Med Sci, 2013;10(13):1817-29.
    PMID: 24324358 DOI: 10.7150/ijms.6902
    Nucleoside analogues such as acyclovir are effective antiviral drugs against herpes simplex virus infections since its introduction. However, with the emergence of acyclovir-resistant HSV strains particularly in immunocompromised patients, there is a need to develop an alternative antiherpetic drug and plants could be the potential lead. In this study, the antiviral activity of the aqueous extract of four Phyllanthus species were evaluated against herpes simplex virus type-1 (HSV-1) and HSV-2 in Vero cells by quantitative PCR. The protein expressions of untreated and treated infected Vero cells were studied by 2D-gel electrophoresis and Western blot. This is the first study that reported the antiviral activity of P. watsonii. P. urinaria was shown to demonstrate the strongest antiviral activity against HSV-1 and HSV-2, with SI >33.6. Time-of-addition studies suggested that the extract may act against the early infection stage and the replication stage. Protein expression studies indicated that cellular proteins that are involved in maintaining cytoskeletal structure could be potential target for development of antiviral drugs. Preliminary findings indicated that P. urinaria demonstrated potent inhibitory activity against HSV. Hence, further studies such as in vivo evaluation are required for the development of effective antiherpetic drug.
    Matched MeSH terms: Cercopithecus aethiops
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