Biology subjects

Yahata, K.

Publications and source records attributed to Yahata, K..

5 recordsLinked to original sources

bioRxiv2026

A PCR-based assay for the sensitive and accurate determination of malaria parasite species that commonly infect humans, including discrimination of Plasmodium ovalecurtisi and Plasmodium ovalewallikeri

There are six Plasmodium species that commonly infect humans including Plasmodium ovalecurtisi, and Plasmodium ovalewallikeri. To ensure successful malaria control, it is important to track their prevalence and understand their epidemiological and clinical characteristics. Current PCR-based malaria diagnostic techniques targeting the highly sensitive mitochondrial genome do not distinguish between the two Plasmodium ovale species. Here we present a PCR-based species typing method targeting the mitochondrial COXIII involving a sensitive, nested PCR with species-specific primers and a simple enzyme digestion to distinguish P. ovalecurtisi and P. ovalewallikeri. The assay is highly specific to each species and highly sensitive, detecting 0.125 and 0.25 parasites per 1 {micro}l of blood from in vitro cultured Plasmodium knowlesi and Plasmodium falciparum respectively. Furthermore, using 30 field samples, we validate its effectiveness in discriminating the two P. ovale spp., identifying 18 P. ovalecurtisi, 16 P. ovalewallikeri, 23 P. falciparum and 17 Plasmodium malariae infections. This novel assay allows the sensitive and accurate diagnosis of P. falciparum, Plasmodium vivax, P. malariae, P. knowlesi, P. ovalecurtisi, and P. ovalewallikeri and can be used to monitor human and zoonotic malaria infections for both diagnosis and epidemiological studies.

molecular biology↗

bioRxiv2025

Plasmodium falciparum diacylglycerol acyltransferase maintains phospholipid homeostasis to regulate sexual differentiation, ER stress, and cytoadhesion

Plasmodium falciparum is the causative agent of human malaria, a life-threating infectious disease that imposes a major global health burden. Lipid metabolism is indispensable for this parasites replication and survival, yet most of the molecular components and mechanisms involved remain poorly understood. In eukaryotes, lipid droplets (LDs) serve as dynamic organelles that store neutral lipids (NLs), buffer lipotoxic stress, and regulate signaling pathways, with their biogenesis controlled by diacylglycerol o-acyltransferases (DGATs). Although P. falciparum encodes a putative DGAT (PF3D7_0322300), its role in the parasite life cycle has not been elucidated. We generated conditional PfDGAT-knockout parasites to investigate the enzymes functional significance. PfDGAT deficiency led to parasite death, accompanied by reduced LD formation, elevated phospholipid levels, and induction of ER stress. Moreover, PfDGAT deletion altered protein trafficking, resulting in the decreased cytoadherence of parasite-infected erythrocytes to human brain microvascular endothelial cells, and suppressed parasite sexual differentiation. Thus, PfDGAT deletion affected multiple aspects of the parasites life cycle, highlighting its critical role in parasite survival and pathogenesis. Our findings provide new insights into parasite lipid homeostasis and highlight DGAT as a potential target of antimalarial intervention.

microbiology↗

bioRxiv2024

Soma-germ contact across the basement membrane in the ovary

Epithelial cells generally interact with other cells and environments at their apical side. At the basal surface, the basement membrane impedes such an interaction. One notable instance is communication between soma and germ cells within the ovary across numerous bilaterian taxa. This contact underlies proper oogenesis and subsequent embryogenesis through facilitating nutrient supply to gametes, exchange of molecules and ions, and participation in signal transduction for primary axis formation. Throughout layers of the history of morphology and cellular biology, there has been emphasis on this heterocellular interaction primarily occurring at the apical side of epithelial cells. Contrary to this long-standing understanding, we uncover that ovarian follicle cells in three myriapod species belonging to phylogenetically basal myriapod clades extend their cytoplasmic processes, penetrating the basement membrane to establish direct contact with oocytes. These discoveries demonstrate the ovarian soma-germ interaction transverse the basement membrane, suggesting that the basal matrix does not always a physical barrier to soma-germ communication. Furthermore, we find that the ovarian somatic cells in a myriapod directly connect with the oogonia or young oocyte before the formation of their basement membrane. This result suggests an overlooked construction manner of heterocellular communication at the basal domain of epithelial cells.

zoology↗

bioRxiv2023

The structural and functional modularity of ovarian follicle epithelium in the pill-millipede Hyleoglomeris japonica (Myriapoda: Diplopoda: Pentazonia: Glomerida) and the morphological reconsideration of somatic tissues around oocytes in Myriapoda

Ovarian somatic tissues around oocytes are essential for oogenesis in many metazoans. The functional ovarian somatic tissues sometimes have structural properties specific to their roles. In contrast, there is no evidence of such structural modularity of the follicle epithelium in Myriapoda, suggesting that myriapod ovarian soma may not participate in oogenesis. The ultrastructural nature of follicle cells also supports solitary oogenesis in most myriapods investigated. In contrast, here, we report two structurally and developmentally distinct domains of the follicle epithelium in the Japanese pill millipede, Hyleoglomeris japonica. The follicle epithelium of H. japonica has a thick cell mass on the apex of the follicle. These thick cells contain the rich rough endoplasmic reticulum, mitochondria, and Goldi bodies and possess many microvilli, indicating synthetic/secretory activities, and become thicker along with the oogenetic progress. Another region of epithelium does not exhibit these features. These results show the structural and functional modularity specific to some functions of the follicle epithelium of H. japonica. Therefore, the follicle epithelium of Myriapoda is divided into 3 types: physiologically functional uniformly, nonfunctional only, and those with both. We suggest the need to reconsider the nature and roles of ovarian somatic tissues of Myriapoda and Arthropoda.

zoology↗

bioRxiv2020

Gliding motility of Plasmodium merozoites

Plasmodium malaria parasites are obligate intracellular protozoans that use a unique form of locomotion, termed gliding motility, to move through host tissues and invade cells. The process is substrate-dependent and powered by an actomyosin motor that drives the posterior translocation of extracellular adhesins which in turn propel the parasite forward. Gliding motility is essential for tissue translocation in the sporozoite and ookinete stages; however, the short-lived erythrocyte-invading merozoite stage has never been observed to undergo gliding movement. Here we show Plasmodium merozoites possess the ability to undergo gliding motility and that this mechanism is likely an important precursor step for successful parasite invasion. We demonstrate that two human infective species, P. falciparum and P. knowlesi, have distinct merozoite motility profiles which may reflect distinct invasion strategies. Additionally, we develop and validate a higher throughput assay to evaluate the effects of genetic and pharmacological perturbations on both the molecular motor and complex signaling cascade that regulates motility in merozoites. The discovery of merozoite motility provides a new model to study the glideosome and may facilitate the pursuit of new targets for malaria treatment. Significance statementPlasmodium malaria parasites use a unique substrate-dependent locomotion termed gliding motility to translocate through tissues and invade cells. Dogma has suggested that the small labile invasive stages that invade erythrocytes, merozoites, use this motility solely to penetrate target erythrocytes. Here we reveal that merozoites use gliding motility for translocation across host cells prior to invasion. This forms an important pre-invasion step that is powered by a conserved actomyosin motor and is regulated by a complex signaling pathway. This work fundamentally changes our understanding of the role of gliding motility and invasion in the blood and will have a significant impact on our understanding of blood stage host-pathogen interactions, parasite biology, and could have implications for vaccine development.

microbiology↗