The silkworm Bombyx mori contains high concentrations of free D-serine, an optical isomer of L-serine. To elucidate its function, we first investigated the localization of D-serine in various organs of silkworm larvae, pupae, and adult moths. Using immunohistochemical analysis with an anti-D-serine antibody, we found D-serine in the microvilli of midgut goblet and cylindrical cells and in peripheral matrix components of testicular and ovarian cells. By spectrophotometric analysis, D-serine was also found in the hemolymph and fat body. D-Alanine was not detected in the various organs by immunohistochemistry. Serine racemase, which catalyzes the inter-conversion of L- and D-serine, was found to co-localize with D-serine, and D-serine production from L-serine by intrinsic serine racemase was suggested. O-Phospho-L-serine is an inhibitor of serine racemase, and it was administered to the larvae to reduce the D-serine level. This reagent decreased the midgut caspase-3 level and caused a delay in spermatogenesis and oogenesis. The reagent also decreased mature sperm and egg numbers, suggesting D-serine participation in these processes. D-Serine administration induced an increase in pyruvate levels in testis, midgut, and fat body, indicating conversion of D-serine to pyruvate. On the basis of these results, together with our previous investigation of ATP biosynthesis in testis, we consider the possible involvement of D-serine in ATP synthesis for metamorphosis and reproduction.
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http://dx.doi.org/10.1016/j.jinsphys.2016.01.006 | DOI Listing |
Nat Commun
January 2025
National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China.
Uropathogenic Escherichia coli (UPEC) is a major cause of urinary tract infections (UTIs). Invasion into bladder epithelial cells (BECs) on the bladder luminal surface via type 1 fimbria is the first critical step in UPEC infection. Although type 1 fimbria expression increases during UPEC invasion of BECs, the underlying regulatory mechanisms remain poorly understood.
View Article and Find Full Text PDFBiomedicines
December 2024
Department of Neurology, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Child Neurodevelopment and Cognitive Disorders, Chongqing 400014, China.
: To establish a mouse model of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis and assess the potential therapeutic benefits of D-serine supplementation in mitigating synaptic plasticity impairments induced by anti-NMDAR antibodies. : Anti-NMDAR antibodies were purified from cerebrospinal fluid (CSF) samples of patients diagnosed with anti-NMDAR encephalitis and verified using a cell-based assay. CSF from patients with non-inflammatory neurological diseases served as the control.
View Article and Find Full Text PDFInt J Neuropsychopharmacol
December 2024
Neurocrine Biosciences, Inc., San Diego, CA, United States.
Hypofunction of the N-methyl-D-aspartate receptor (NMDAR) has been proposed to underlie the pathophysiology of schizophrenia, suggesting that promoting NMDAR activity may alleviate the negative or cognitive symptoms associated with schizophrenia. To circumvent excitotoxicity that may accompany direct agonism of the glutamate binding site on the NMDAR, therapeutic trials have focused on targeting the glycine binding site on the NMDAR. Direct administration of either glycine or D-serine, both of which are endogenous coagonists at the NMDAR glycine site, has yielded mixed outcomes across an array of clinical trials investigating different doses or patient populations.
View Article and Find Full Text PDFSchizophrenia (Heidelb)
December 2024
CEINGE Biotecnologie Avanzate Franco Salvatore, Naples, Italy.
Schizophrenia (SCZ) is a severe psychotic disorder characterized by a disruption in glutamatergic NMDA receptor (NMDAR)-mediated neurotransmission. Compelling evidence has revealed that NMDAR activation is not limited to L-glutamate, L-aspartate, and glycine since other free amino acids (AAs) in the atypical D-configuration, such as D-aspartate and D-serine, also modulate this class of glutamatergic receptors. Although dysregulation of AAs modulating NMDARs has been previously reported in SCZ, it remains unclear whether distinct variations of these biomolecules occur during illness progression from at-risk premorbid to clinically manifest stage.
View Article and Find Full Text PDFYakugaku Zasshi
December 2024
Department of Pharmacology, Faculty of Pharmaceutical Science, Health Sciences University of Hokkaido.
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