Publications by authors named "Shigeharu Sato"

Background: The increasing incidence of Plasmodium knowlesi malaria poses a significant challenge to efforts to eliminate malaria from Malaysia. Macaque reservoirs, outdoors-biting mosquitoes, human activities, and agricultural work are key factors associated with the transmission of this zoonotic pathogen. However, gaps in knowledge regarding reasons that drive malaria persistence in rural Kudat, Sabah, Northern Borneo remain.

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Background: The control of Plasmodium knowlesi malaria remains challenging due to the presence of macaque monkeys and predominantly outdoor-biting Anopheles mosquitoes around human settlements. This study aims to explore the barriers and facilitators related to prevention of mosquito bites among rural communities living in Sabah, Malaysia using the participatory visual method, photovoice.

Methods: From January through June 2022, 26 participants were recruited from four villages in Kudat, Sabah, using purposive sampling.

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Article Synopsis
  • - The malaria parasite has a unique organelle called the apicoplast, which has its own genome and is essential for its life cycle, but how its genes are regulated is not well understood.
  • - Researchers discovered a specific RNA polymerase σ subunit that helps control the accumulation of apicoplast transcripts, and this process may relate to the parasite’s biological clock.
  • - The study found that the hormone melatonin, related to circadian rhythms, boosts the expression of apicoplast genes, suggesting a link between the host’s biological clock and the parasite's gene regulation, which could be targeted for malaria treatments.
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Background: Many rural communities in Malaysian Borneo and Southeast Asia are at risk of Plasmodium knowlesi malaria. Multiple factors contribute to infection, however, a deep understanding of illness causation and prevention practices among at-risk communities remains limited. This study aims to document local knowledge on malaria causation and preventive practices of rural communities in Sabah, Malaysia, using photovoice-a participatory research method.

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Malaria is one of the most devastating infectious diseases of humans. It is problematic clinically and economically as it prevails in poorer countries and regions, strongly hindering socioeconomic development. The causative agents of malaria are unicellular protozoan parasites belonging to the genus Plasmodium.

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(Pk) is a malaria parasite that naturally infects macaque monkeys in Southeast Asia. Pk malaria, the zoonosis transmitted from the infected monkeys to the humans by mosquito vectors, is now a serious health problem in Malaysian Borneo. To create a strategic plan to control Pk malaria, it is important to estimate the occurrence of the disease correctly.

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Mosquito surveillance is a fundamental component of planning and evaluating vector control programmes. However, logistical and cost barriers can hinder the implementation of surveillance, particularly in vector-borne disease-endemic areas and in outbreak scenarios in remote areas where the need is often most urgent. The increasing availability and reduced cost of 3D printing technology offers an innovative approach to overcoming these challenges.

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The growth and the survival of the human malaria parasite Plasmodium falciparum are critically dependent on the functions of the two organelles - the mitochondrion and the apicoplast. However, these two organelles have been known to be difficult to separate from each other when they are released from Plasmodium cell. We have been searching for the conditions with which separation of the mitochondrion and the apicoplast is achieved.

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Leucocytozoon caulleryi, a haemosporidian parasite of the chicken (Gallus gallus domesticus), can be highly pathogenic and often fatal. Although this parasite is extremely relevant to veterinary science, knowledge of its genomic features is limited. To gain information applicable to developing novel control methods for the parasite, we analyzed the apicoplast genome of L.

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Haem biosynthesis appeared to be a target of malaria therapy because 5-aminolevulinic acid (ALA), a haem biosynthesis starting material, with light exposure or a high amount of ALA alone reduced Plasmodium falciparum growth to undetectable level. However, the administration of a high dose of ALA is unrealistic for clinical therapy. We found that Fe(2+) enhanced P.

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The apicoplast, a non-photosynthetic plastid of apicomplexan species, has an extremely reduced but highly conserved genome. Here, the apicoplast genome of the rodent malaria parasite Plasmodium chabaudi chabaudi (Pcc) isolate CB was characterized. Although the set of genes in the genome is identical, the copy number of some tRNA genes differs between Pcc and other Plasmodium species because the Pcc DNA has only one rRNA/tRNA gene cluster, which is normally duplicated in other species.

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Autophagy is a membrane-mediated degradation process, which is governed by sequential functions of Atg proteins. Although Atg proteins are highly conserved in eukaryotes, protozoa possess only a partial set of Atg proteins. Nonetheless, almost all protozoa have the complete factors belonging to the Atg8 conjugation system, namely, Atg3, Atg4, Atg7, and Atg8.

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Protistan species belonging to the phylum Apicomplexa have a non-photosynthetic secondary plastid-the apicoplast. Although its tiny genome and even the entire nuclear genome has been sequenced for several organisms bearing the organelle, the reason for its existence remains largely obscure. Some of the functions of the apicoplast, including housekeeping ones, are significantly different from those of other plastids, possibly due to the organelle's unique symbiotic origin.

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The nuclear genome of the human malaria parasite Plasmodium falciparum encodes a homolog of the bacterial HU protein (PfHU). In this study, we characterised PfHU's physiological function. PfHU, which is targeted exclusively to the parasite's plastid, bound its natural target--the plastid DNA--sequence-independently and complemented lack of HU in Escherichia coli.

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The mitochondrion and the apicoplast of the malaria parasite, Plasmodium spp. is microscopically observed in a close proximity to each other. In this study, we tested the suitability of two different separation techniques--Percoll density gradient centrifugation and fluorescence-activated organelle sorting--for improving the purity of mitochondria isolated from the crude organelle preparation of Plasmodium falciparum.

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We report the genome sequence of Theileria parva, an apicomplexan pathogen causing economic losses to smallholder farmers in Africa. The parasite chromosomes exhibit limited conservation of gene synteny with Plasmodium falciparum, and its plastid-like genome represents the first example where all apicoplast genes are encoded on one DNA strand. We tentatively identify proteins that facilitate parasite segregation during host cell cytokinesis and contribute to persistent infection of transformed host cells.

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The replication and repair of organellar genomes in the malaria parasite Plasmodium falciparum is poorly understood. We have assessed the properties of an open reading frame Pfprex (formerly known as pom1) and confirm that it specifies a multi-domain polypeptide with DNA primase, DNA helicase, DNA polymerase and 3'-5' exonuclease activities. The sequence of the primase/helicase domain is phylogenetically related to the T7-bacteriophage gene 4 product and mammalian mitochondrial helicase, Twinkle.

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Protein maturation in eukaryotic organelles requires the type I chaperonin system; this comprises chaperonin 60 (Cpn60) and its cochaperonin. We have re-examined and revised the sequence of the nuclear genes specifying organellar cochaperonins in Plasmodium falciparum (Pf). One gene encodes a typical cochaperonin (PfCpn10) whereas the other (encoding PfCpn20) specifies two Cpn10 domains arranged in tandem as in plant chloroplasts.

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All eight enzymes required for de novo heme biosynthesis have been predicted from the nuclear genome of the human malaria parasite Plasmodium falciparum. We have studied the subcellular localization of three of these using a GFP reporter in live transfected parasites. The first enzyme in the pathway delta-aminolevulinic acid synthase (ALAS) is targeted to the mitochondrion, but the next two enzymes porphobilinogen synthase (PBGS) and hydroxymethylbilane synthase (HMBS) are targeted to the plastid.

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A gene encoding the heme biosynthetic enzyme ferrochelatase (FC) was found in the genomic DNA databases of Plasmodium spp. The predicted amino acid sequence of malarial FC is highly conserved and fairly well conserved by comparison with other orthologues. The FC genes of P.

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The enzyme delta-aminolevulinic acid dehydratase (ALAD) catalyses the second reaction in the heme biosynthetic pathway. It has been suggested previously that the malaria parasite Plasmodium falciparum imports this enzyme from the host cell for de novo heme biosynthesis. However, the parasite's genome encodes an orthologue for ALAD.

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