Publications by authors named "Motomichi Matsuzaki"
Ubiquinone (UQ) is a lipophilic electron carrier that functions in the respiratory and photosynthetic electron transfer chains of proteobacteria and eukaryotes. Bacterial UQ biosynthesis is well studied in the gammaproteobacterium Escherichia coli, in which most bacterial UQ-biosynthetic enzymes have been identified. However, these enzymes are not always conserved among UQ-containing bacteria.
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- * The AI system was trained to analyze 12 segments of the uterovaginal area for high-grade lesions, achieving a recall rate of 62.1% and an overall correct response rate of 89.7%.
- * Results showed a significant correlation between the AI's detection rates and evaluations made by experienced gynecologic oncologists, highlighting the potential of AI as a valuable tool in the management of cervical conditions.
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- Intracellular pathogens often replicate in vacuoles to evade host defenses, and while some recruit host mitochondria, the specific recruiting molecules are mostly unknown.
- In Toxoplasma gondii, mitochondrial association factor 1b (MAF1b) is known, and this study identifies rhoptry kinase family protein 39 (ROP39) as a new factor that helps host mitochondrial recruitment.
- Observations showed an increased presence of ROP39 on host mitochondria in infected human foreskin fibroblasts, and a knockout of ROP39 led to a 10% decrease in mitochondrial association, indicating its significant role.
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- Genetic manipulation of marine protists is challenging, but Perkinsus marinus shows promise as a model organism for genetic studies.
- Researchers developed a new plasmid that utilizes a self-cleaving 2A peptide to enable different localization of two proteins from one mRNA.
- This system successfully created a stable transfectant with a fluorescent protein targeted to mitochondria, offering a powerful tool for studying organelles in P. marinus and similar species.
Sequences homologous to human herpesvirus 6 (HHV-6) are integrated within the nuclear genome of about 1% of humans, but it is not clear how this came about. It is also uncertain whether integrated HHV-6 can reactivate into an infectious virus. HHV-6 integrates into telomeres, and this has recently been associated with polymorphisms affecting MOV10L1.
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- Toxoplasma gondii is divided into 16 haplogroups globally, but the study highlighted a limited representation of Japanese isolates, prompting a more focused examination.
- Researchers analyzed the DNA sequences of 17 Japanese isolates and categorized them into four distinct groups, discovering a highly virulent strain that parallels a well-known RH strain in terms of virulence in mice.
- The study also compared specific virulence-related genes in the Japanese isolate to those of other archetypical strains, finding that variations in genes ROP5 and ROP16 contributed to its high virulence and helped enhance understanding of the parasite's biodiversity.
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- * The TgCatJpOk4 strain, isolated in Okinawa, shows high virulence in laboratory mice, similar to the highly virulent RH strain, but its effects on domestic animals were previously unknown.
- * In a study using Microminipigs, four out of five infected pigs exhibited severe symptoms, with three succumbing, revealing that the TgCatJpOk4 strain also has significant virulence in pigs, causing interstitial pneumonia and liver necrosis.
Complete biosynthetic pathways of ascofuranone and ascochlorin in .
Proc Natl Acad Sci U S A
April 2019
Ascofuranone (AF) and ascochlorin (AC) are meroterpenoids produced by various filamentous fungi, including (synonym: ), and exhibit diverse physiological activities. In particular, AF is a promising drug candidate against African trypanosomiasis and a potential anticancer lead compound. These compounds are supposedly biosynthesized through farnesylation of orsellinic acid, but the details have not been established.
View Article and Find Full Text PDFPerkinsus marinus is a marine protozoan parasite that infects natural and farmed oysters, attracting attention from researchers in both fisheries and evolutionary biology. The functions of almost all cellular components and organelles are, however, poorly understood even though a draft genome sequence of P. marinus is publicly available.
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- Paulinella micropora is a type of amoeba that has a unique organelle called a chromatophore, which evolved from cyanobacteria, setting it apart from plant and algal chloroplasts.
- This species is valuable for studying primary endosymbiosis because its acquisition of the chromatophore happened more recently compared to plants and algae.
- The study examined mRNA 5' end sequences to find that 27 genes, including those transferred from endosymbionts, had a specific sequence that’s added post-transcriptionally, highlighting the unique SL trans-splicing process in this organism.
Some organisms have retained plastids even after they have lost the ability to photosynthesize. Several studies of nonphotosynthetic plastids in apicomplexan parasites have shown that the isopentenyl pyrophosphate biosynthesis pathway in the organelle is essential for their survival. A phytohormone, abscisic acid, one of several compounds biosynthesized from isopentenyl pyrophosphate, regulates the parasite cell cycle.
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- Perkinsus species are harmful unicellular parasites that affect important shellfish like clams and oysters, impacting the aquaculture industry.
- Recent research advancements in molecular biology can help us understand these parasites better and develop infection control methods.
- The introduction of a drug selection system using bleomycin allows for better genetic manipulation of Perkinsus marinus by selectively identifying transfected cells, opening new avenues for studying this parasite.
Drug resistance compromises control of malaria. Here, we show that resistance to a commonly used antimalarial medication, atovaquone, is apparently unable to spread. Atovaquone pressure selects parasites with mutations in cytochrome b, a respiratory protein with low but essential activity in the mammalian blood phase of the parasite life cycle.
View Article and Find Full Text PDFTo investigate the evolution of centromere architecture in plant cells, it is important to identify centromere regions of primitive algae, such as Cyanidioschyzon merolae. In a previous genome project, in silico analysis predicted an AT-rich region in each chromosome as putative centromere regions. Here, we identified a centromere position in each chromosome by ChIP-on-chip analysis using an anti-CENP-A antibody.
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- Atovaquone is a drug used to combat malaria by targeting the cytochrome bc1 complex in the mitochondrial respiratory chain of the malaria parasite, Plasmodium spp.
- Mutations in the cytochrome b gene, such as Y268C and Y268N, are associated with increased resistance to atovaquone, although direct evidence linking these mutations to drug resistance has been challenging to obtain.
- Recent advancements in isolating mitochondria from Plasmodium berghei allowed researchers to test drug resistance directly, with findings indicating that resistant clones have significantly higher IC(50) values for atovaquone compared to sensitive strains, confirming the role of specific mutations in conferring resistance.
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- The chlorarachniophytes obtained their plastids through secondary endosymbiosis from an ancestral green alga, leading to expected "green" genes in their nuclear genomes.
- Recent studies, however, show unexpected "red" genes in these genomes, prompting research into their origins.
- Phylogenetic analysis revealed multiple horizontal gene transfers from red lineages to chlorarachniophytes, suggesting that these red genes likely came from photosynthetic eukaryotes, which might indicate prior endosymbiotic events or prolonged interactions with red algal species.
Perkinsus marinus (Phylum Perkinsozoa) is a protozoan parasite that has devastated natural and farmed oyster populations in the USA, significantly affecting the shellfish industry and the estuarine environment. The other two genera in the phylum, Parvilucifera and Rastrimonas, are parasites of microeukaryotes. The Perkinsozoa occupies a key position at the base of the dinoflagellate branch, close to its divergence from the Apicomplexa, a clade that includes parasitic protista, many harbouring a relic plastid.
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- Dinoflagellate mitochondrial genomes have unique and complicated genetic systems that differ from the standard nuclear systems and often use altered genetic codes.
- Researchers sequenced the full-length cytochrome c oxidase subunit 1 (cox1) mRNA from an early dinoflagellate, Perkinsus, and discovered that it requires 10 reading frame shifts to produce the corresponding COX1 protein.
- The study proposes two potential mechanisms for these frameshifts: ribosomes skipping bases of specific codons or specialized tRNAs that recognize non-traditional codons, indicating advanced translational machinery is necessary for this process.
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- The phylogenetic relationships among major photosynthetic eukaryotes, specifically Archaeplastida (green plants, red algae, glaucophytes) and the secondary photosynthetic group Haptophyta, are influenced by the data used in previous studies.
- This study analyzed the phylogeny of these groups using sequences from slowly evolving nuclear genes while minimizing gaps in the data, particularly for glaucophytes.
- The findings indicate that Haptophyta, alongside stramenopiles and Alveolata, form a monophyletic group that is closely related to green plants, with glaucophytes and red algae emerging as more primitive within this evolutionary context.
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- Eukaryotic genes with cyanobacterial origins in plastid-lacking protists are key evolutionary markers, indicating early plastid presence in eukaryotes, though their distribution and origins are not well-studied.
- A study identified 12 cyanobacterial gene families in various eukaryotic groups, mainly in bikonts, using a new phylogenetic method, while noting some exceptions in certain organisms.
- The findings suggest that these genes may have come from lateral gene transfer or ancient endosymbiosis events, displaying a unique multi-gene family structure across eukaryotes.
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- For over 140 years, scientists believed that pollen tubes in flowering plants were guided by attractants from ovules, but concrete evidence for a specific molecule was lacking.
- Recent research has identified secreted cysteine-rich polypeptides (CRPs) from synergid cells as key attractants in the final stage of pollen tube guidance.
- In experiments with the plant Torenia fournieri, two specific CRPs, named LUREs, were shown to effectively attract pollen tubes, and blocking these molecules reduced attraction, confirming their role as the signaling attractants.
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- Plastids are important in plants and algae, and nonphotosynthetic protists like malarial parasites also utilize them, suggesting hidden plastids might exist in other protists.
- This study focused on the parasite Perkinsus marinus, which is linked to plastid-bearing organisms, and analyzed its methylerythritol phosphate (MEP) pathway genes, finding that six of these genes resemble those in plastid-containing eukaryotes.
- The findings, including the discovery of potential plastid-like structures in Perkinsus marinus, support the hypothesis that this organism is a cryptic algal group, and help advance our understanding of plastid evolution among both photosynthetic and nonphotosynthetic eukaryotes.
Centromere dynamics are largely unknown in lower plants (algae). We have recently identified the centromere-specific histone H3 variant (CENH3) and clarified the dynamic centromere rearrangement at mitosis in the primitive red alga Cyanidioschyzon merolae. We also showed that the CENH3-containing nucleosomes constituted the kinetochore closely interacting with the nuclear envelope.
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- Previous nuclear genome sequences of eukaryotes were incomplete, particularly in repetitive DNA regions, making it difficult to fully understand their biology; the study of the hot-spring alga Cyanidioschyzon merolae aimed to address these gaps and provide a complete genome analysis.
- The new complete genome sequence spans over 16.5 million nucleotides and includes all 20 linear chromosomes, revealing unique features like the smallest histone-gene cluster and a distinctive telomeric repeat.
- The findings suggest that C. merolae has the simplest nuclear genome among non-symbiotic eukaryotes, which may facilitate future research on eukaryotic cell biology.