記述言語：英語   掲載種別：研究論文（学術雑誌）  

Cryptosporidium parvum is an apicomplexan parasite that causes severe zoonotic diarrhea in humans and calves. Since there are no effective treatments or vaccines for infants or immunocompromised patients, it is important to understand the molecular mechanisms of the parasite-host interaction for novel drug discovery. Mitogen-activated protein kinase (MAP kinase) is a key host factor in interactions between host and various pathogens, including parasites. Although the function of conventional MAP kinases against parasite infection has been investigated, that of atypical MAP kinases remains largely unknown. Therefore, we focused on one of the atypical MAP kinases, MAPK4, and its effect on C. parvum infection in human intestinal cells. Here, we report that MAPK4-deficient intestinal cells showed a significant reduction in C. parvum infection. We also show that host MAPK4 has a role in host cell survival from C. parvum infection. In addition, we show that C. parvum requires host MAPK4 for its successful invasion and asexual reproduction. Taken together, our data suggest that MAPK4 is an important host factor contributing to C. parvum infection in human intestinal cells.

DOI： 10.1038/s41598-023-28269-w

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

During sexual reproduction/conjugation of the ciliate Tetrahymena thermophila, the germinal micronucleus undergoes meiosis resulting in four haploid micronuclei (hMICs). All hMICs undergo post-meiotic DNA double-strand break (PM-DSB) formation, cleaving their genome. DNA lesions are subsequently repaired in only one ‘selected’ hMIC, which eventually produces gametic pronuclei. DNA repair in the selected hMIC involves chromatin remodeling by switching from the heterochromatic to the euchromatic state of its genome. Here, we demonstrate that, among the 15 Tetrahymena Snf2 family proteins, a core of the ATP-dependent chromatin remodeling complex in Tetrahymena, the germline nucleus specific Iswi in Tetrahymena IswiGTt and Rad5Tt is crucial for the generation of gametic pronuclei. In either gene knockout, the selected hMIC which shows euchromatin markers such as lysine-acetylated histone H3 does not appear, but all hMICs in which markers for DNA lesions persist are degraded, indicating that both IswiGTt and Rad5Tt have important roles in repairing PM-DSB DNA lesions and remodeling chromatin for the euchromatic state in the selected hMIC.

DOI： 10.3390/microorganisms10122426

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Cryptosporidium spp. are gastrointestinal opportunistic protozoan parasites that infect humans, domestic animals, and wild animals all over the world. Cryptosporidiosis is the second leading infectious diarrheal disease in infants less than 5 years old. Cryptosporidiosis is a common zoonotic disease associated with diarrhea in infants and immunocompromised individuals. Consequently, cryptosporidiosis is considered a serious economic, veterinary, and medical concern. The treatment options for cryptosporidiosis are limited. To address this problem, we screened a natural product library containing 87 compounds of Traditional Chinese Medicines for anti-Cryptosporidium compounds that could serve as novel drug leads and therapeutic targets against C. parvum. To examine the anti-Cryptosporidium activity and half-maximal inhibitory doses (EC50) of these compounds, we performed in vitro assays (Cryptosporidium growth inhibition assay and host cell viability assay) and in vivo experiments in mice. In these assays, the C. parvum HNJ-1 strain was used. Four of the 87 compounds (alisol-A, alisol-B, atropine sulfate, and bufotalin) showed strong anti-Cryptosporidium activity in vitro (EC50 values = 122.9±6.7, 79.58±13.8, 253.5±30.3, and 63.43±18.7 nM, respectively), and minimum host cell cytotoxicity (cell survival > 95%). Furthermore, atropine sulfate (200 mg/kg) and bufotalin (0.1 mg/kg) also showed in vivo inhibitory effects. Our findings demonstrate that atropine sulfate and bufotalin are effective against C. parvum infection both in vitro and in vivo. These compounds may, therefore, represent promising novel anti-Cryptosporidium drug leads for future medications against cryptosporidiosis.

DOI： 10.1371/journal.pntd.0010947

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Frontiers Media SA  

<italic>Toxoplasma gondii</italic> chronically infects the brain as latent cysts containing bradyzoites and causes various effects in the host. Recently, the molecular mechanisms of cyst formation in the mouse brain have been elucidated, but those in the human brain remain largely unknown. Here, we show that abnormal glutamine metabolism caused by both interferon-γ (IFN-γ) stimulation and <italic>T. gondii</italic> infection induce cyst formation in human neuroblastoma cells regardless of the anti-<italic>T. gondii</italic> host factor nitric oxide (NO) level or Indoleamine 2,3-dioxygenase-1 (IDO1) expression. IFN-γ stimulation promoted intracellular glutamine degradation in human neuronal cells. Additionally, <italic>T. gondii</italic> infection inhibited the mRNA expression of the host glutamine transporters SLC38A1 and SLC38A2. These dual effects led to glutamine starvation and triggered <italic>T. gondii</italic> stage conversion in human neuronal cells. Furthermore, these mechanisms are conserved in human iPSC-derived glutamatergic neurons. Taken together, our data suggest that glutamine starvation in host cells is an important trigger of <italic>T. gondii</italic> stage conversion in human neurons.

DOI： 10.3389/fcimb.2021.788303

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

Sporozoites of the etiological agent of malaria, Plasmodium, form parasitophorous vacuoles (PVs) in hepatocytes. The PV membranes (PVM) are coated with a well-known host autophagy marker LC3 and parasite-derived protein called Upregulated in infective sporozoites 3 (UIS3), which has been shown to interact with LC3 and inhibit LC3-mediated autophagic disruption at the PV. Although uis3(−) sporozoites cannot proliferate in wild-type cells, they can replicate efficiently in cells defective in autophagy due to the lack of Atg proteins such as Atg3, Atg5 and Atg7, since these Atg proteins are essential for processing of LC3. However, it remains to be seen whether other Atg proteins participate in the restriction of uis3(−) parasite growth. Here we show that, despite essential roles of Atg9 and Atg14 in autophagy, both proteins are dispensable for the restriction of uis3(−) parasite growth. Moreover, we found that cells lacking LC3 proteins are also able to restrict uis3(−) parasite growth. In sharp contrast, GABARAPs, another subfamily of mammalian Atg8, participated in suppression of uis3(−) parasite growth. Taken together, contrary to a previous model in which UIS3 avoids host LC3- and autophagy-dependent parasite elimination program, our data demonstrate a role of GABARAPs for suppression of uis3(−) parasite growth in a manner independent on autophagy.

DOI： 10.1016/j.parint.2021.102335

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出版者・発行元：Cold Spring Harbor Laboratory  

<title>ABSTRACT</title><italic>Plasmodium falciparum</italic> parasites are the major cause of malaria across Africa. Due to the appearance of multi-drug resistant parasites, new antimalarial drugs are needed. The medicinal plant <italic>Phyllanthus niruri</italic> is being used to treat fever and other symptoms of malaria in Nigeria; however, little is known about its antimalarial mechanisms. Here, we show that aqueous extract of <italic>P. niruri</italic> (PE) has multiple antimalarial effects, including anti-parasitic and host immunomodulatory activity. We found that co-culture of <italic>P. falciparum</italic> with PE drastically reduced parasite number, but PE did not inhibit parasite development or rupture; rather, it blocked erythrocytes invasion. In addition, we identified Astragalin as one of the antimalarial compounds which are contained in PE. Moreover, we found that PE suppresses the inflammatory activity and apoptosis of immune cells (T cells) and astrocytes and neurons in the central nervous system (CNS). Furthermore, we confirmed that oral administration of PE to mice suppressed parasite growth, excessive inflammation, CNS dysfunction, and the development of experimental cerebral malaria in an <italic>in vivo</italic> murine malaria model. Our findings demonstrate that PE has multiple effects on malaria progression, targeting both parasite and host cells.

DOI： 10.1101/2021.07.09.451735

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

Cryptosporidium and Toxoplasma are parasites that have caused problems worldwide. Cryptosporidium causes severe watery diarrhoea and may be fatal in immunocompromised patients and in infants. Nitazoxanide is the only agent currently approved by the FDA, but its efficacy is limited. Toxoplasmosis is also a problem in the immunocompromised, as currently available treatment options have limited efficacy and patient tolerance can be poor. In the present investigation, we screened libraries of epigenetic compounds to identify those that inhibited C. parvum growth. Nullscript was identified as a compound with an inhibitory effect on C. parvum and T. gondii growth, and was less toxic to host cells. Nullscript was also able to significantly decrease oocyst excretion in C. parvum-infected SCID mice.

DOI： 10.1016/j.ijpddr.2020.10.004

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

The studies on Cryptosporidium infections of animals in Turkey mostly rely on microscopic observation. Few data are available regarding the prevalence of Cryptosporidium genotypes and subtypes infection. The aim of this study is to analyse the detection of Cryptosporidium genotypes and subtypes from young ruminants. A total of 415 diarrheic fecal specimens from young ruminants were examined for the Cryptosporidium detection by use of nested PCR of the small subunit ribosomal RNA (SSU rRNA) gene and the highly polymorphic 60 kDa glycoprotein (gp60) gene followed by sequence analyses. The results of this study revealed that 25.6% (106 of 415) of the specimens were positive for Cryptosporidium spp. infection. We identified 27.4% (91/333), 19.4% (13/67), and 13.4% (2/15) of positivity in calves, lambs and goat kids, respectively. Genotyping of the SSU rRNA indicated that almost all positive specimens were of C. parvum, except for one calf which was of C. bovis. Sequence analysis of the gp60 gene revealed the most common zoonotic subtypes (IIa and IId) of C. parvum. We detected 11 subtypes (IIaA11G2R1, IIaA11G3R1, IIaA12G3R1, IIaA13G2R1, IIaA13G4R1, IIaA14G1R1, IIaA14G3R1, IIaA15G2R1, IIdA16G1, IIdA18G1, IIdA22G1); three of them (IIaA12G3R1, IIaA11G3R1 and IIaA13G4R1) was novel subtypes found in calves and lambs. Additionally, three subtypes (IIaA11G2R1, IIaA14G3R1, and IIdA16G1) were detected in young ruminants for the first time in Turkey. These results indicate the high infection of Cryptosporidium in Turkey and propose that young ruminants are likely a major reservoir of C. parvum and a potential source of zoonotic transmission.

DOI： 10.1016/j.parint.2020.102163

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.parint.2020.102153

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Frontiers Media SA  

Sepsis is a life-threating multi-organ disease induced by host innate immunity to pathogen-derived endotoxins including lipopolysaccharide (LPS). Direct sensing of LPS by caspase-11 activates inflammasomes and causes lethal sepsis in mice. Inhibition of caspase-11 inflammasomes is important for the prevention of LPS-induced septic shock; however, whether a caspase-11 inflammasome-specific suppressive mechanism exists is unclear. Here we show that deficiency of GABARAP autophagy-related proteins results in over-activation of caspase-11 inflammasomes but not of canonical inflammasomes. Gate-16-/-Gabarap-/- macrophages exhibited elevated guanylate binding protein 2 (GBP2)-dependent caspase-11 activation and inflammatory responses. Deficiency of GABARAPs resulted in formation of GBP2-containing aggregates that promote IL-1β production. High mortality after low dose LPS challenge in Gate-16-/-Gabarap-/- mice primed with poly(I:C) or polymicrobial sepsis was ameliorated by compound GBP2 deficiency. These results reveal a critical function of Gate-16 and Gabarap to suppress GBP2-dependent caspase-11-induced inflammation and septic shock.

DOI： 10.3389/fimmu.2020.561948

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

Fisch et al. find that GBP1 targets Toxoplasma vacuolar and parasite membranes for disruption of both membranes. In contrast, appearance of cytosolic Salmonella is GBP1 independent, but caspase-4 recruitment to bacteria and activation is GBP1 dependent. In a negative feedback loop, caspase-1 cleaves GBP1 and suppresses caspase-4-driven pyroptosis during Salmonella infection.

DOI： 10.1016/j.celrep.2020.108008

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Faculty of Veterinary Medicine, Hokkaido University  

DOI： 10.14943/jjvr.68.3.159

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Most mammalian species have a vomeronasal organ that detects specific chemical substances, such as pheromones. Mucous fluid covering the vomeronasal sensory epithelium is secreted by vomeronasal glands, and the properties of these fluids have been suggested to be involved in chemical detection. Histological studies using periodic acid-Schiff (PAS) and Alcian blue pH 2.5 (AB) stains, which respectively detect natural and acidic polysaccharides, have suggested variations in the nature of the vomeronasal glands among species. Here, we investigated the responsivity of the vomeronasal glands to PAS and AB stains in eight Laurasiatheria species. All species studied herein possessed vomeronasal glands that stained positive for PAS, like other many reported species. The vomeronasal glands of dogs and minks - like rodents, were AB-negative, whereas those of cows, goats, sika deer, musk shrews and two bat species were positive. Considering the present findings and previous reports, the vomeronasal glands in most of Laurasiatheria species appear to be fundamentally abundant in acidic polysaccharides, whereas those in carnivores essentially contains neutral polysaccharides.

DOI： 10.1016/j.acthis.2020.151515

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

© 2019 Bando et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms/). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/). The liver stage of the etiological agent of malaria, Plasmodium, is obligatory for successful infection of its various mammalian hosts. Differentiation of the rod-shaped sporozoites of Plasmodium into spherical exoerythrocytic forms (EEFs) via bulbous expansion is essential for parasite development in the liver. However, little is known about the host factors regulating the morphological transformation of Plasmodium sporozoites in this organ. Here, we show that sporozoite differentiation into EEFs in the liver involves protein kinase C ζ–mediated NF-κB activation, which robustly induces the expression of C-X-C chemokine receptor type 4 (CXCR4) in hepatocytes and subsequently elevates intracellular Ca2+ levels, thereby triggering sporozoite transformation into EEFs. Blocking CXCR4 expression by genetic or pharmacological intervention profoundly inhibited the liver-stage development of the Plasmodium berghei rodent malaria parasite and the human Plasmodium falciparum parasite. Collectively, our experiments show that CXCR4 is a key host factor for Plasmodium development in the liver, and CXCR4 warrants further investigation for malaria prophylaxis.

DOI： 10.1084/jem.20182227

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The guanylate binding protein (GBP) family of interferon-inducible GTPases promotes antimicrobial immunity and cell death. During bacterial infection, multiple mouse Gbps, human GBP2, and GBP5 support the activation of caspase-1-containing inflammasome complexes or caspase-4 which trigger pyroptosis. Whether GBPs regulate other forms of cell death is not known. The apicomplexan parasite Toxoplasma gondii causes macrophage death through unidentified mechanisms. Here we report that Toxoplasma-induced death of human macrophages requires GBP1 and its ability to target Toxoplasma parasitophorous vacuoles through its GTPase activity and prenylation. Mechanistically, GBP1 promoted Toxoplasma detection by AIM2, which induced GSDMD-independent, ASC-, and caspase-8-dependent apoptosis. Identical molecular determinants targeted GBP1 to Salmonella-containing vacuoles. GBP1 facilitated caspase-4 recruitment to Salmonella leading to its enhanced activation and pyroptosis. Notably, GBP1 could be bypassed by the delivery of Toxoplasma DNA or bacterial LPS into the cytosol, pointing to its role in liberating microbial molecules. GBP1 thus acts as a gatekeeper of cell death pathways, which respond specifically to infecting microbes. Our findings expand the immune roles of human GBPs in regulating not only pyroptosis, but also apoptosis.

DOI： 10.15252/embj.2018100926

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掲載種別：研究論文（学術雑誌）  

DOI： 10.15252/embj.2018100926

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3389/fcimb.2019.00140

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1128/mBio.01738-18

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3389/fimmu.2018.02073

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：NATURE PUBLISHING GROUP  

Mammalian autophagy-related 8 (Atg8) homologs consist of LC3 proteins and GABARAPs, all of which are known to be involved in canonical autophagy. In contrast, the roles of Atg8 homologs in noncanonical autophagic processes are not fully understood. Here we show a unique role of GABARAPs, in particular gamma-aminobutyric acid (GABA)-A-receptor-associated protein-like 2 (Gabarapl2; also known as Gate-16), in interferon-gamma (IFN-gamma)-mediated antimicrobial responses. Cells that lacked GABARAPs but not LC3 proteins and mice that lacked Gate-16 alone were defective in the IFN-gamma-induced clearance of vacuolar pathogens such as Toxoplasma. Gate-16 but not LC3b specifically associated with the small GTPase ADP-ribosylation factor 1 (Arf1) to mediate uniform distribution of interferon-inducible GTPases. The lack of GABARAPs reduced Arf1 activation, which led to formation of interferon-inducible GTPase-containing aggregates and hampered recruitment of interferon-inducible GTPases to vacuolar pathogens. Thus, GABARAPs are uniquely required for antimicrobial host defense through cytosolic distribution of interferon-inducible GTPases.

DOI： 10.1038/ni.3767

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：NATURE PUBLISHING GROUP  

The malaria parasite Plasmodium berghei is one of the main rodent malaria models. A shortcoming of this model parasite is its low flexibility in genetic manipulation. As this parasite cannot be continuously propagated in cell cultures, in vivo drug selection procedures are necessary to isolate genetic mutants. Drugs harmful to rodents therefore cannot be used for drug selection, which restricts the range of genetic manipulation. In this study, we addressed this problem by establishing a novel in vitro culture drug selection method, which we used in combination with other established methods to successfully isolate genetically manipulated parasites. The target mutants were enriched to the desired level within two weeks. We show that our system can also be used for sequential genetic manipulation of parasites carrying the traditionally used selection markers, demonstrate the procedure's versatility, and show its use in isolating specific genetically manipulated parasites. This novel in vitro selection method increases the number of available selection markers, allowing more extensive genetic manipulation in malaria parasite research.

DOI： 10.1038/s41598-017-04244-0

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BIOMED CENTRAL LTD  

Background: Malaria vectors have developed resistance to the four families of insecticides available for public health purposes. For example, the kdr mutation is associated with organochlorines and pyrethroids resistance. It is of particular concern that organophosphate and carbamate resistance associated with the G119S ace-1(R) mutation has recently increased in West Africa in extent and frequency, and is now spreading through the Anopheles gambiae malaria vector population. There is an urgent need to improve resistance management using existing insecticides and new tools to quickly assess resistance level for rapid decision-making.
Methods: DNA extracted from field-collected mosquitoes was used to develop the method. Specific primers were designed manually to match the mutation region and an additional mismatched nucleotide in the penultimate position to increase specificity. Other primers used are common to both wild and mutant types. The allele specific (AS)-LAMP method was compared to the PCR restriction fragment length polymorphism (PCR-RFLP) and real-time PCR (RT-PCR) methods using the genomic DNA of 104 field-collected mosquitoes.
Results: The primers designed for LAMP were able to distinguish between the wild type (ace-1(S)) and mutated type allele (ace-1(R)). Detection time was 50 min for the wild type homozygous and 64 min for the heterozygous. No amplification of the resistant allele took place within the 75-min test period when using the wild type primers. For the ace-1(R) resistant type, detection time was 51 min for the resistant homozygous and 55 min for the heterozygous. No amplification of the wild type allele took place within the 75-min test period when using the resistant type primers. Gel electrophoresis of LAMP products confirmed that amplification was primer-DNA specific, i.e., primers could only amplify their target specific DNA. AS-LAMP, PCR-RFLP, and RT-PCR showed no significant difference in the sensitivity and specificity of their ace-1(R) detection ability.
Conclusions: The AS-LAMP method could detect the ace-1(R) mutation within 60 min, which is faster than conventional PCR-RFLP. This method may be used to quickly detect the ace-1(R) mutation for rapid decision-making, even in less well-equipped laboratories.

DOI： 10.1186/s12936-015-0968-9

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：NATL RESEARCH CENTER PROTOZOAN DISEASES  

Toxoplasma gondii is one of the most common protozoan parasites globally and requires both a definitive and an intermediate host to complete its life cycle. The population of wild sika deer (Cervus nippon yesoensis) in eastern Hokkaido, Japan, has recently increased and is considered a potential intermediate host of T gondii. In this study, the seroprevalence of T gondii infection in 201 wild sika deer from 10 geographical regions in eastern Hokkaido in 2010 and 2011 was analyzed using the latex agglutination test. Antibodies to T gondii were found in three cases (1.5% of samples), suggesting that deer have started to function as intermediate hosts. This is the first report of seropositivity against T. gondii in wild sika deer in eastern Hokkaido.

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.celrep.2015.09.005

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1073/pnas.1510031112

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ROCKEFELLER UNIV PRESS  

Toxoplasma gondii infection results in co-option and subversion of host cellular signaling pathways. This process involves discharge of T. gondii effector molecules from parasite secretory organelles such as rhoptries and dense granules. We report that the T. gondii polymorphic dense granule protein GRA6 regulates activation of the host transcription factor nuclear factor of activated T cells 4 (NFAT4). GRA6 overexpression robustly and selectively activated NFAT4 via calcium modulating ligand (CAMLG). Infection with wildtype (WT) but not GRA6-deficient parasites induced NFAT4 activation. Moreover, GRA6-deficient parasites failed to exhibit full virulence in local infection, and the treatment of WT mice with an NFAT inhibitor mitigated virulence of WT parasites. Notably, NFAT4-deficient mice displayed prolonged survival, decreased recruitment of CD11b(+) Ly6G(+) cells to the site of infection, and impaired expression of chemokines such as Cxcl2 and Ccl2. In addition, infection with type I parasites culminated in significantly higher NFAT4 activation than type II parasites due to a polymorphism in the C terminus of GRA6. Collectively, our data suggest that GRA6-dependent NFAT4 activation is required for T. gondii manipulation of host immune responses to maximize the parasite virulence in a strain-dependent manner.

DOI： 10.1084/jem.20131272

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILDLIFE DISEASE ASSOC, INC  

We analyzed blood samples of resident and migratory Japanese birds to evaluate the prevalence and genetic background of avian blood parasites in northern Japan. We used PCR targeting the mitochondrial cytochrome b gene to examine infections of Leucocytozoon, Haemoproteus, and Plasmodium parasites in blood samples from 243 birds of 14 species in three orders (Passeriformes, Columbiformes, and Anseriformes). Sequences were subjected to phylogenetic analysis. The infection rate was 21% in pigeons (Columbiformes) and 17% in Anseriformes. A high infection rate of 93.8% was found in crow species (Passeriformes). Haemoproteus and Plasmodium parasites were detected in only two species. Infected blood samples obtained from seven bird species involved two major clades of Leucocytozoon, which were divided between resident and migratory birds. The parasites, which are genetically distinct from parasites in Japanese resident birds, may have been introduced to Japan by migratory bird species.

DOI： 10.7589/2013-03-071

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記述言語：英語   出版者・発行元：MANEY PUBLISHING  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：NATURE PUBLISHING GROUP  

A critical stage in malaria transmission occurs in the Anopheles mosquito midgut, when the malaria parasite, Plasmodium, ingested with blood, first makes contact with the gut epithelial surface. To understand the response mechanisms within the midgut environment, including those influenced by resident microbiota against Plasmodium, we focus on a midgut bacteria species' intra-specific variation that confers diversity to the mosquito's competency for malaria transmission. Serratia marcescens isolated from either laboratory-reared mosquitoes or wild populations in Burkina Faso shows great phenotypic variation in its cellular and structural features. Importantly, this variation is directly correlated with its ability to inhibit Plasmodium development within the mosquito midgut. Furthermore, this anti-Plasmodium function conferred by Serratia marcescens requires increased expression of the flagellum biosynthetic pathway that is modulated by the motility master regulatory operon, flhDC. These findings point to new strategies for controlling malaria through genetic manipulation of midgut bacteria within the mosquito.

DOI： 10.1038/srep01641

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BIOMED CENTRAL LTD  

Background: Malaria control relies heavily on treated bed nets and indoor residual spraying with pyrethroid insecticides. Unfortunately, the resistance to pyrethroid insecticides, mainly due to the kdr mutation, is spreading in the main malaria vector Anopheles gambiae s.l., decreasing the insecticides' efficacy. To manage the insecticide resistance rapidly and flexibly, simple and effective tools for the early detection of resistant mosquitoes are needed. This study aimed to develop an allele-specific, loop-mediated, isothermal amplification (AS-LAMP) method to detect the West African-type kdr mutation (kdr-w; L1014F) in field-collected mosquitoes.
Methods: DNA fragments of the wild-type and the mutated kdr gene were used to select the primers and develop the method. The primers were designed with the mutation at the 5' end of the backward inner primer (BIP). The AS-LAMP method was compared to the AS-PCR method using the genomic DNA of 120 field-collected mosquitoes.
Results: The AS-LAMP method could discriminate between the wild-type homozygote, the heterozygote, and the kdr-w homozygote within 75 min. The AS-LAMP method has the advantage of being faster and at least as sensitive and specific as the AS-PCR method. Conclusions: The AS-LAMP method can be used to detect the kdr mutation for quick decision-making, even in less well-equipped laboratories.

DOI： 10.1186/1475-2875-11-227

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BIOMED CENTRAL LTD  

Background: Despite recent advances in our understanding of the basic biology behind transmission of zoonotic infectious diseases harbored by arthropod vectors these diseases remain threatening public health concerns. For effective control of vector and treatment, precise sampling indicating the prevalence of such diseases is essential. With an aim to develop a quick and simple method to survey zoonotic pathogen-transmitting vectors, LAMP (loop-mediated isothermal amplification) was applied to the detection of filarial parasites using a filarial parasite-transmitting experimental model that included one of the mosquito vectors, Aedes aegypti, and the canine heartworm, Dirofilaria immitis.
Results: LAMP reactions amplifying the cytochrome oxidase subunit I gene demonstrated high sensitivity when a single purified D. immitis microfilaria was detected. Importantly, the robustness of the LAMP reaction was revealed upon identification of an infected mosquito carrying just a single parasite, a level easily overlooked using conventional microscopic analysis. Furthermore, successful detection of D. immitis in wild-caught mosquitoes demonstrated its applicability to field surveys.
Conclusion: Due to its simplicity, sensitivity, and reliability, LAMP is suggested as an appropriate diagnostic method for routine diagnosis of mosquito vectors carrying filarial parasites. This method can be applied to the survey of not only canine filariasis but also lymphatic filariasis, another major public health problem. Therefore, this method offers great promise as a useful diagnostic method for filarial parasite detection in endemic filariasis regions.

DOI： 10.1186/1756-3305-2-15

Web of Science

PubMed

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記述言語：日本語  

J-GLOBAL

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記述言語：日本語  

J-GLOBAL

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記述言語：日本語  

CiNii Books

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その他リンク： http://search.jamas.or.jp/link/ui/2012092339

記述言語：日本語  

J-GLOBAL

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記述言語：日本語   掲載種別：記事・総説・解説・論説等（大学・研究所紀要）   出版者・発行元：東京慈恵会医科大学  

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記述言語：日本語  

J-GLOBAL

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J-GLOBAL

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記述言語：日本語  

J-GLOBAL

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記述言語：日本語  

J-GLOBAL

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記述言語：日本語  

J-GLOBAL

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開催年月日： 2023年3月

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開催年月日： 2020年11月

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開催年月日： 2020年11月

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開催年月日： 2020年9月

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開催年月日： 2019年5月

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開催年月日： 2015年5月

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種別：フェスティバル

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所属研究室主催にて開催に尽力した。

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