Publications by authors named "Tetsuya Miyamoto"

Glucose-6-Phosphatase (G6Pase), a key enzyme in gluconeogenesis and glycogenolysis in the mammalian liver and kidney, converts glucose-6-phosphate to glucose for maintaining systemic blood glucose homeostasis during nutrient deprivation. However, its function has remained elusive in insects, which have no need for G6Pase in sugar homeostasis since they convert glucose-6-phosphate to trehalose, their main circulating sugar, via trehalose phosphate synthase (TPS1). In this study we identify an unexpected and essential requirement for G6Pase in male fertility, specifically to produce motile sperm.

View Article and Find Full Text PDF

The peptidoglycan of the hyperthermophile Thermotoga maritima contains an unusual D-lysine in addition to the typical D-alanine and D-glutamate. Previously, we identified the D-lysine and D-glutamate biosynthetic pathways of T. maritima.

View Article and Find Full Text PDF

Neuropeptides (NPs) and their cognate receptors are critical effectors of diverse physiological processes and behaviors. We recently reported of a noncanonical function of the () gene in a subset of neurosecretory cells in the central nervous system that governs systemic glucose homeostasis in food-deprived flies. Here, we show that expressing neurons define six groups of NP-secreting cells, four in the brain and two in the thoracic ganglion.

View Article and Find Full Text PDF
Article Synopsis
  • The study analyzed data from the Tokyo 2020 Games to understand why athletes were transferred to local medical facilities, focusing on 567 injuries and illnesses treated at on-site clinics.
  • During the Olympics, most athlete transfers were due to injuries (72.7%), with a small percentage requiring hospitalization for more than 7 days, while the Paralympics had a more balanced distribution with half of the cases being other illnesses.
  • This research highlights the significant volume and types of medical issues athletes faced, providing insights not previously recorded in earlier Olympic and Paralympic events.*
View Article and Find Full Text PDF

In bacteria, d-amino acids are primarily synthesized from l-amino acids by amino acid racemases, but some bacteria use d-amino acid aminotransferases to synthesize d-amino acids. d-Amino acids are peptidoglycan components in the cell wall involved in several physiological processes, such as bacterial growth, biofilm dispersal, and peptidoglycan metabolism. Therefore, their metabolism and physiological roles have attracted increasing attention.

View Article and Find Full Text PDF

Unlabelled: Neuropeptides (NPs) and their cognate receptors are critical effectors of diverse physiological processes and behaviors. We recently reported of a non-canonical function of the ( ) gene in a subset of neurosecretory cells in the CNS that governs systemic glucose homeostasis in food deprived flies. Here, we show that expressing neurons define 6 groups of neuropeptide secreting cells, 4 in the brain and 2 in the thoracic ganglion.

View Article and Find Full Text PDF

d-Serine plays vital physiological roles in the functional regulation of the mammalian brain, where it is produced from l-serine by serine racemase and degraded by d-amino acid oxidase. In the present study, we identified a new d-serine metabolizing activity of serine hydroxymethyltransferase (SHMT) in bacteria as well as mammals. SHMT is known to catalyze the conversion of l-serine and tetrahydrofolate (THF) to glycine and 5,10-methylenetetrahydrofolate, respectively.

View Article and Find Full Text PDF
Article Synopsis
  • A study analyzed injuries and illnesses among 11,420 athletes during the 2020 Tokyo Olympic Games, focusing on the period from July 21 to August 8, 2021.
  • A total of 567 athletes and 541 non-athletes were treated for a variety of injuries and illnesses, with marathons and race walking showing the highest incidence of issues.
  • The overall rates of injuries and heat-related illnesses were lower than expected, attributed to effective preparation and medical protocols at the venues, with no serious events reported.
View Article and Find Full Text PDF

Introduction: Among the 43 venues of Tokyo 2020 Olympic Games (OG) and 33 venues of Paralympic Games (PG) were held, the heat island effect was highly expected to cause heat-related illnesses in the outdoor venues with maximum temperatures exceeding 35°C. However, the actual number of heat-related illness cases during the competition was lower than that was initially expected, and it was unclear under what conditions or environment-related heat illnesses occurred among athletes.

Object: To clarify the cause and factors contributing to the occurrence of heat-related illness among athletes participating in the Tokyo 2020 Olympic and Paralympic Games.

View Article and Find Full Text PDF

While chicken eggs contain many nutrients necessary for humans and there are various cooking methods, the nutritional components are used as they are, and there are no traditional foods that utilize microorganisms. Koji-mold, containing Aspergillus oryzae, A. sojae, and A.

View Article and Find Full Text PDF

Noncanonical D-amino acids are involved in peptidoglycan and biofilm metabolism in bacteria. Previously, we identified amino acid racemases with broad substrate specificity, including YgeA from Escherichia coli, which strongly prefers homoserine as a substrate. In this study, we investigated the functions of this enzyme in vivo.

View Article and Find Full Text PDF

Various d-amino acids play important physiological roles in mammals, but the pathways of their production remain unknown except for d-serine, which is generated by serine racemase. Previously, we found that Escherichia coli cystathionine β-lyase possesses amino acid racemase activity in addition to β-lyase activity. In the present work, we evaluated the enzymatic activities of human cystathionine γ-lyase, which shares a relatively high amino acid sequence identity with cystathionine β-lyase.

View Article and Find Full Text PDF
Article Synopsis
  • Thermotoga maritima, a hyperthermophilic bacterium, has an unusual peptidoglycan structure featuring d-lysine, but lacks specific enzymes for the biosynthesis of d-alanine and d-glutamate, making their pathways unclear.
  • Researchers identified a new enzyme, TM0831, which acts as a d-amino acid aminotransferase, showing high activity for various d-amino acids and racemase activity towards some, including aspartate and glutamate.
  • The study demonstrated that engineering a mutant strain of Thermus thermophilus to include TM0831 significantly improved growth, indicating that TM0831 plays a crucial role in the production of d-glutamate in T
View Article and Find Full Text PDF

The hyperthermophilic bacterium Thermotoga maritima peptidoglycan contains unusual d-lysine alongside typical d-alanine and d-glutamate. We previously identified lysine racemase and threonine dehydratase, but knowledge of d-amino acid metabolism remains limited. Herein, we identified and characterized T.

View Article and Find Full Text PDF

Multiple d-amino acids are present in mammalian cells, and these compounds have distinctive physiological functions. Among the free d-amino acids identified in mammals, d-aspartate plays critical roles in the neuroendocrine and endocrine systems, as well as in the central nervous system. Mammalian cells have the molecular apparatus necessary to take up, degrade, synthesize, and release d-aspartate.

View Article and Find Full Text PDF

The peptidoglycan of the hyperthermophile Thermotoga maritima contains an unusual component, D-lysine (D-Lys), in addition to the typical D-alanine (D-Ala) and D-glutamate (D-Glu). In a previous study, we identified a Lys racemase that is presumably associated with D-Lys biosynthesis. However, our understanding of D-amino acid metabolism in T.

View Article and Find Full Text PDF

Bacteria produce diverse d-amino acids, which are essential components of cell wall peptidoglycan. Incorporation of these d-amino acids into peptidoglycan contributes to bacterial adaptation to environmental changes and threats. d-Amino acids have been associated with bacterial growth, biofilm formation and dispersal and regulation of peptidoglycan metabolism.

View Article and Find Full Text PDF

d-Serine (d-Ser) is a coagonist for NMDA-type glutamate receptors and is thus important for higher brain function. d-Ser is synthesized by serine racemase and degraded by d-amino acid oxidase. However, the significance of these enzymes and the relevant functions of d-amino acids remain unclear.

View Article and Find Full Text PDF

In mammals, metabolism of free d-glutamate is regulated by d-glutamate cyclase (DGLUCY), which reversibly converts d-glutamate to 5-oxo-d-proline and HO. Metabolism of these d-amino acids by DGLUCY is thought to regulate cardiac function. In this study, we established a simple, accurate, and sensitive colorimetric assay method for measuring DGLUCY activity.

View Article and Find Full Text PDF

d-Amino acids are physiologically important components of peptidoglycan in the bacterial cell wall, maintaining cell structure and aiding adaptation to environmental changes through peptidoglycan remodelling. Therefore, the biosynthesis of d-amino acids is essential for bacteria to adapt to different environmental conditions. The peptidoglycan of the extremely thermophilic bacterium Thermus thermophilus contains d-alanine (d-Ala) and d-glutamate (d-Glu), but its d-amino acid metabolism remains poorly understood.

View Article and Find Full Text PDF

d-Aspartate oxidase (DDO) is a flavin adenine dinucleotide (FAD)-containing flavoprotein that stereospecifically acts on acidic d-amino acids (i.e., free d-aspartate and d-glutamate).

View Article and Find Full Text PDF

Bacteria produce various D-amino acids, including non-canonical D-amino acids, to adapt to environmental changes and overcome a variety of threats. These D-amino acids are largely utilized as components of peptidoglycan, and they promote peptidoglycan remodeling and biofilm disassembly. The biosynthesis, maturation, and recycling of peptidoglycan are catalyzed by penicillin-binding proteins (PBPs).

View Article and Find Full Text PDF

Gluconeogenesis is a well-established metabolic process whereby glucose is generated from small carbon molecules in the liver and kidney to maintain blood glucose levels. Expression of gluconeogenic genes has been reported in other organs of mammals and insects, where their function is not yet known. In the fruit fly, one of the gluconeogenic genes, glucose-6-phosphatase (G6P) is exclusively expressed in the CNS.

View Article and Find Full Text PDF

Various d-amino acids are involved in peptidoglycan and biofilm metabolism in bacteria, suggesting that these compounds are necessary for successful adaptation to environmental changes. In addition to the conventional d-alanine (d-Ala) and d-glutamate, the peptidoglycan of the hyperthermophilic bacterium Thermotoga maritima contains both l-lysine (l-Lys) and d-Lys, but not meso-diaminopimelate (meso-Dpm). d-Lys is an uncommon component of peptidoglycan, and its biosynthetic pathway remains unclear.

View Article and Find Full Text PDF