GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Surveillance on the Vivax Malaria in Endemic Areas in the Republic of Korea Based on Molecular and Serological Analyses
    Korean Society for Parasitology ; 2020
    In:  The Korean Journal of Parasitology Vol. 58, No. 6 ( 2020-12-29), p. 609-617
    Details
    In: The Korean Journal of Parasitology, Korean Society for Parasitology, Vol. 58, No. 6 ( 2020-12-29), p. 609-617
    Abstract: 〈 i 〉 Plasmodium vivax 〈 /i 〉 reemerged in 1993. It has been sustained for more than 25 years and become one of the important indigenous parasitic diseases in northern and western parts of the Republic of Korea near the demilitarized zone. In particular, relapse is a significant concern for the control of malaria, as short- and long-term incubation periods vary among those infected in Korea. In this study, the prevalence of asymptomatic carriers was examined among residents of high endemic areas of vivax malaria during nonseasonal transmission of mosquitoes. Blood samples from 3 endemic regions in northwestern Korea were evaluated by microscopic examination, rapid diagnostic testing, and nested PCR to identify asymptomatic patients carrying malaria parasites in the community. However, no positive malaria case among residents of endemic areas was detected. Additionally, serological analysis was carried out to measure antibodies against 3 antigenic recombinant proteins of 〈 i 〉 P. vivax 〈 /i 〉 , merozoite surface protein 1-19, circumsporozoite surface protein-VK210, and liver-stage antigen (PvLSA-N), by the protein array method. Interestingly, seropositivity of sera between previous exposure and samples without exposure to malaria was significantly higher using the PvLSA-N antigen than the other antigens, suggesting that PvLSA-N can be used as a serological marker to analyze the degree of exposure for malaria transmission in endemic areas. This indicates a very low asymptomatic carrier prevalence during the nonmalaria season in the endemic areas of Korea.
    Type of Medium: Online Resource
    ISSN: 0023-4001 , 1738-0006
    URL: Article
    DOI: 10.3347/kjp.2020.58.6.609
    Language: English
    Publisher: Korean Society for Parasitology
    Publication Date: 2020
    detail.hit.zdb_id: 2163174-8
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Identification of Reticulocyte Binding Domain of Plasmodium ovale curtisi Duffy Binding Protein (PocDBP) Involved in Reticulocyte Invasion
    Frontiers Media SA ; 2021
    In:  Frontiers in Cellular and Infection Microbiology Vol. 11 ( 2021-12-10)
    Details
    In: Frontiers in Cellular and Infection Microbiology, Frontiers Media SA, Vol. 11 ( 2021-12-10)
    Abstract: The Plasmodium ovale curtisi (Poc) prevalence has increased substantially in sub-Saharan African countries as well as regions of Southeast Asia. Poc parasite biology has not been explored much to date; in particular, the invasion mechanism of this malaria parasite remains unclear. In this study, the binding domain of the Duffy binding protein of P. ovale curtisi (PocDBP) was characterized as an important ligand for reticulocyte invasion. The homologous region of the P. vivax Duffy binding protein in PocDBP, named PocDBP-RII herein, was selected, and the recombinant PocDBP-RII protein was expressed in an Escherichia coli system. This was used to analyze reticulocyte binding activity using fluorescence-activated cell sorting and immune serum production in rabbits. The binding specificity was proven by treating reticulocytes with trypsin, chymotrypsin and neuraminidase. The amino acid sequence homology in the N-terminal Cys-rich region was found to be ~ 44% between PvDBP and PocDBP. The reticulocyte binding activity of PocDBP-RII was significantly higher than the erythrocyte binding activity and was concentration dependent. Erythrocyte binding was reduced significantly by chymotrypsin treatment and inhibited by an anti-PocDBP-RII antibody. This finding suggests that PocDBP may be an important ligand in the reticulocyte invasion process of P. ovale curtisi.
    Type of Medium: Online Resource
    ISSN: 2235-2988
    URL: Article
    DOI: 10.3389/fcimb.2021.764293
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2619676-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Prevalence of pvmrp1 Polymorphisms and Its Contribution to Antimalarial Response
    MDPI AG ; 2022
    In:  Microorganisms Vol. 10, No. 8 ( 2022-07-22), p. 1482-
    Details
    In: Microorganisms, MDPI AG, Vol. 10, No. 8 ( 2022-07-22), p. 1482-
    Abstract: As more sporadic cases of chloroquine resistance occur (CQR) in Plasmodium vivax (P. vivax) malaria, molecular markers have become an important tool to monitor the introduction and spread of drug resistance. P. vivax multidrug resistance-associated protein 1 (PvMRP1), as one of the members of the ATP-binding cassette (ABC) transporters, may modulate this phenotype. In this study, we investigated the gene mutations and copy number variations (CNVs) in the pvmrp1 in 102 P. vivax isolates from China, the Republic of Korea (ROK), Myanmar, Papua New Guinea (PNG), Pakistan, the Democratic People’s Republic of Korea (PRK), and Cambodia. And we also obtained 72 available global pvmrp1 sequences deposited in the PlasmoDB database to investigate the genetic diversity, haplotype diversity, natural selection, and population structure of pvmrp1. In total, 29 single nucleotide polymorphisms reflected in 23 non-synonymous, five synonymous mutations and one gene deletion were identified, and CNVs were found in 2.9% of the isolates. Combined with the antimalarial drug susceptibility observed in the previous in vitro assays, except the prevalence of S354N between the two CQ sensitivity categories revealed a significant difference, no genetic mutations or CNVs associated with drug sensitivity were found. The genetic polymorphism analysis of 166 isolates worldwide found that the overall nucleotide diversity (π) of pvmrp1 was 0.0011, with 46 haplotypes identified (Hd = 0.9290). The ratio of non-synonymous to synonymous mutations (dn/ds = 0.5536) and the neutrality tests statistic Fu and Li’s D* test (Fu and Li’s D* = −3.9871, p 〈 0.02) suggests that pvmrp1 had evolved under a purifying selection. Due to geographical differences, genetic differentiation levels of pvmrp1 in different regions were different to some extent. Overall, this study provides a new idea for finding CQR molecular monitoring of P. vivax and provides more sequences of pvmrp1 in Asia for subsequent research. However, further validation is still needed through laboratory and epidemiological field studies of P. vivax samples from more regions.
    Type of Medium: Online Resource
    ISSN: 2076-2607
    URL: Article
    DOI: 10.3390/microorganisms10081482
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2720891-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Immunogenicity and antigenicity of a conserved fragment of the rhoptry-associated membrane antigen of Plasmodium vivax
    Springer Science and Business Media LLC ; 2022
    In:  Parasites & Vectors Vol. 15, No. 1 ( 2022-11-15)
    Details
    In: Parasites & Vectors, Springer Science and Business Media LLC, Vol. 15, No. 1 ( 2022-11-15)
    Abstract: Plasmodium vivax rhoptry-associated membrane antigen (RAMA) is a glycophosphatidylinositol-anchored membrane protein currently under consideration as a malaria vaccine candidate. Immunoglobulin G (IgG) antibodies induced by P. vivax RAMA (PvRAMA) have been proved to persist over 12 months in the sera of people infected with P. vivax. It has also been shown that through stimulation of peripheral blood mononuclear cells with PvRAMA in vitro, the antigen can induce CD4 + T cells to produce interleukin-10. However, the genetic diversity of the RAMA gene in isolates of P. vivax ( pvrama ) and the immunogenicity of PvRAMA in animals remain unclear. Methods Genomic DNA was extracted from blood samples ( n  = 25) of patients in Jiangsu Province, China with imported infections of P. vivax from endemic countries in South and Southeast Asia. The extract genomic DNA was used as templates to amplify the P. vivax rama gene ( pvrama ) by PCR, and the PCR products were then sequenced and analyzed by the DnaSP, MEGA, and GeneDoc software packages. Recombinant PvRAMA (rPvRAMA) protein was expressed and purified, and then used to immunize mice. Levels of total IgG and different IgG subclasses of rPvRAMA-immunized mice were evaluated by enzyme-linked immunosorbent assay. Also, spleen cells of rPvRAMA-immunized mice were stimulated with rPvRAMA in vitro and levels of T cells were measured by flow cytometry. Results The average pairwise nucleotide diversity ( π ) of the pvrama gene was 0.00190, and the haplotype diversity ( Hd ) was 0.982. The C-terminal of PvRAMA showed lower haplotype diversity compared to the N-terminal and was completely conserved at amino acid sites related to erythrocyte binding. To further characterize immunogenicity of the C-terminal of PvRAMA, mice were immunized with rPvRAMA antigen. The rPvRAMA protein induced antibody responses, with the end-point titer ranging from 1:10,000 to 1:5,120,000. IgG1 was the predominant IgG subclass in rPvRAMA-immunized mice, followed by IgG2b. In addition, levels of CD4 + and CD8 + T cells in the rPvRAMA-stimulated group were significantly higher than those in the phosphate-buffered saline-stimulated group (normal control group). Conclusions The high conservation at specific amino acid sites and the high immunogenicity of the C-terminal of PvRAMA indicate the presence of conserved epitopes able to generate broadly reactive humoral and cellular immune responses. These findings support the potential of PvRAMA to serve as a vaccine candidate against P. vivax infection. Graphical Abstract
    Type of Medium: Online Resource
    ISSN: 1756-3305
    URL: Article
    DOI: 10.1186/s13071-022-05561-8
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2409480-8
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Elicitation of T-cell-derived IFN-γ-dependent immunity by highly conserved Plasmodium ovale curtisi Duffy binding protein domain region II (PocDBP-RII)
    Springer Science and Business Media LLC ; 2023
    In:  Parasites & Vectors Vol. 16, No. 1 ( 2023-08-08)
    Details
    In: Parasites & Vectors, Springer Science and Business Media LLC, Vol. 16, No. 1 ( 2023-08-08)
    Abstract: Infections with Plasmodium ovale are widely distributed but rarely investigated, and the resulting burden of disease has been underestimated. Plasmodium ovale curtisi Duffy binding protein domain region II ( PocDBP-RII ) is an essential ligand for reticulocyte recognition and host cell invasion by P. ovale curtisi . However, the genomic variation, antigenicity and immunogenicity of PocDBP-RII remain major knowledge gaps. Methods A total of 93 P. ovale curtisi samples were collected from migrant workers who returned to China from 17 countries in Africa between 2012 and 2016. The genetic polymorphism, natural selection and copy number variation (CNV) were investigated by sequencing and real-time PCR. The antigenicity and immunogenicity of the recombinant PocDBP-RII (rPocDBP-RII) protein were further examined, and the humoral and cellular responses of immunized mice were assessed using protein microarrays and flow cytometry. Results Efficiently expressed and purified rPocDBP-RII (39 kDa) was successfully used as an antigen for immunization in mice. The haplotype diversity (Hd) of PocDBP-RII gene was 0.105, and the nucleotide diversity index (π) was 0.00011. No increased copy number was found among the collected isolates of P. ovale curtisi . Furthermore, rPocDBP-RII induced persistent antigen-specific antibody production with a serum IgG antibody titer of 1: 16,000. IFN-γ-producing T cells, rather than IL-10-producing cells, were activated in response to the stimulation of rPocDBP-RII. Compared to PBS-immunized mice (negative control), there was a higher percentage of CD4 + CD44 high CD62L − T cells (effector memory T cells) and CD8 + CD44 high CD62L + T cells (central memory T cells) in rPocDBP-RII‑immunized mice. Conclusions PocDBP-RII sequences were highly conserved in clinical isolates of P. ovale curtisi . rPocDBP-RII protein could mediate protective blood-stage immunity through IFN-γ-producing CD4 + and CD8 + T cells and memory T cells, in addition to inducing specific antibodies. Our results suggested that rPocDBP-RII protein has potential as a vaccine candidate to provide assessment and guidance for malaria control and elimination activities. Graphical Abstract
    Type of Medium: Online Resource
    ISSN: 1756-3305
    URL: Article
    DOI: 10.1186/s13071-023-05897-9
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2409480-8
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    Image_2.TIF
    Frontiers Media SA ; 2022
    In:  Frontiers in Microbiology Vol. 13 ( 2022-11-24)
    Details
    In: Frontiers in Microbiology, Frontiers Media SA, Vol. 13 ( 2022-11-24)
    Abstract: Merozoite invasion of the erythrocytes in humans is a key step in the pathogenesis of malaria. The proteins involved in the merozoite invasion could be potential targets for the development of malaria vaccines. Novel viral-vector-based malaria vaccine regimens developed are currently under clinical trials. Vesicular stomatitis virus (VSV) is a single-stranded negative-strand RNA virus widely used as a vector for virus or cancer vaccines. Whether the VSV-based malarial vaccine is more effective than conventional vaccines based on proteins involved in parasitic invasion is still unclear. In this study, we have used the reverse genetics system to construct recombinant VSVs (rVSVs) expressing apical membrane protein 1 (AMA1), rhoptry neck protein 2 (RON2), and reticulocyte-binding protein homolog 5 (RH5), which are required for Plasmodium falciparum invasion. Our results showed that VSV-based viral vaccines significantly increased Plasmodium -specific IgG levels and lymphocyte proliferation. Also, VSV-PyAMA1 and VSV-PyRON2sp prime-boost regimens could significantly increase the levels of IL-2 and IFN-γ-producing by CD4 + and CD8 + T cells and suppress invasion in vitro . The rVSV prime-protein boost regimen significantly increase Plasmodium antigen-specific IgG levels in the serum of mice compared to the homologous rVSV prime-boost. Furthermore, the protective efficacy of rVSV prime protein boost immunization in the mice challenged with P. yoelii 17XL was better compared to traditional antigen immunization. Together, our results show that VSV vector is a novel strategy for malarial vaccine development and preventing the parasitic diseases.
    Type of Medium: Online Resource
    ISSN: 1664-302X
    URL: Article
    URL: Article
    URL: Article
    DOI: 10.3389/fmicb.2022.1042414
    DOI: 10.3389/fmicb.2022.1042414.s001
    DOI: 10.3389/fmicb.2022.1042414.s002
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2587354-4
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...