Ami D et al. (2004) FEBS Lett "Fourier transform infrared microspectroscopy as a new tool for nematode studies."

Doglia SM, Ami D, Zullini A, Natalello A

[FEBS Lett, 2004]

We report the results of a microspectroscopy study on the Fourier transform infrared (FT-IR) absorption spectra of Caenorhabditis elegans, collected from the different parts of a single intact specimen - pharynx, intestine and tail regions. The principal absorption bands were assigned to the molecular species present in C. elegans, with an excellent reproducibility for the pharynx spectrum. These results enabled us to explore if FT-IR microspectroscopy could offer a new tool for nematode identification. As an example, the discrimination among four well characterised nematode taxa is reported. The FT-IR results completely match those obtained by Blaxter and colleagues through molecular biology [Nature 392 (1998) 71].

Ami D et al. (2012) Methods Mol Biol "Fourier transform infrared microspectroscopy of complex biological systems: from intact cells to whole organisms."

Doglia SM, Natalello A, Ami D

[Methods Mol Biol, 2012]

Fourier transform infrared (FTIR) microspectroscopy is a powerful tool for the study of complex biological systems. Indeed, it is employed to characterize intact cells, tissues, and whole model organisms such as nematodes, since it allows to obtain a chemical fingerprint of the sample under investigation, giving information on the molecular composition and structures. The successful application of this technique for the in situ study of biological processes requires specific sample preparations, in order to obtain reliable and reproducible results. In the present work, we illustrate the optimized procedures to prepare biological samples for IR measurements and the method to collect and analyze their FTIR spectra. In particular, we describe here the investigations on bacterial cells, intact eukaryotic cells, and whole intact nematode specimens.

Murakami, S. (2011) International Worm Meeting "Clarifying misconceptions about age-related memory impairment (AMI)."

Murakami, S.

[International Worm Meeting, 2011]

Age-related memory impairment (AMI) includes mild impairment of the ability to learn new information and to recall previously learned information. The term, age-associated cognitive impairment (AACI), is also used to describe memory impairment during aging. We define AMI (or AAMI) as memory impairment in comparison with young normal controls (young v.s. old comparison); and AACI as in comparison with age-matched normal counterparts (non-AMI v.s. AMI comparison at the same age) (1). We prefer using AMI over AAMI, since AAMI is often confused with the transition state, MCI. Here we clarify some misconceptions we encountered through scientific communication. Firstly, AMI is not a simple decrease in learning and memory. Recent studies suggest that aging causes not only declines but also increases of learning and memory. AMI is not a gradual decay but rather an aspect of age-related alterations in the nervous functions. Importantly, neural loss plays a minor role in AMI. Secondly, AMI is not a disease. AMI is a normal state prior to the disease state. What distinguishes AMI from dementia besides cognitive deficits? A few lines of evidence analysis in humans suggest that reduced metabolic activity may be a hallmark of AMI in humans. Finally, AMI cannot be independent of aging. There is an argument that aging should be separated from AMI. However, aging affects learning and memory, which results in AMI. More precisely, AMI is caused by age-related processes that affect learning and memory. The age-related processes should include age-related changes in neurons as well as elsewhere, including modifiers and pathways for learning and memory. In fact, a type of AMI can be suppressed by serotonin inhibitors, which are good examples for such modifiers. It is unlikely that aging neurons are the sole cause of AMI. Thus, focusing only on neurons would miss important aspects of the mechanisms for AMI. Although the study of aging neurons has been emphasized, it is equally essential to investigate the aging processes. More details are discussed in Ref. 1. The abstract may be presented with the other presentation. Reference: 1. Murakami, S., Cabana, K., Anderson, D. Current advances in the study of oxidative stress and age-related memory impairment in C. elegans. John Wiley & Sons, Hoboken, NJ. In Press.

Sakoguchi H et al. (2016) Biosci Biotechnol Biochem "Screening of biologically active monosaccharides: growth inhibitory effects of d-allose, d-talose, and l-idose against the nematode Caenorhabditis elegans."

Izumori K, Yoshihara A, Sakoguchi H, Sato M

[Biosci Biotechnol Biochem, 2016]

We compared the growth inhibitory effects of all aldohexose stereoisomers against the model animal Caenorhabditis elegans. Among the tested compounds, the rare sugars d-allose (d-All), d-talose (d-Tal), and l-idose (l-Ido) showed considerable growth inhibition under both monoxenic and axenic culture conditions. 6-Deoxy-d-All had no effect on growth, which suggests that C6-phosphorylation by hexokinase is essential for inhibition by d-All.

Sakoguchi H et al. (2016) Bioorg Med Chem Lett "Growth inhibitory effect of d-arabinose against the nematode Caenorhabditis elegans: Discovery of a novel bioactive monosaccharide."

Shintani T, Izumori K, Sato M, Sakoguchi H, Okuma K, Yoshihara A

[Bioorg Med Chem Lett, 2016]

Biological activities of unusual monosaccharides (rare sugars) have largely remained unstudied until recently. We compared the growth inhibitory effects of aldohexose stereoisomers against the animal model Caenorhabditis elegans cultured in monoxenic conditions with Escherichia coli as food. Among these stereoisomers, the rare sugar d-arabinose (d-Ara) showed particularly strong growth inhibition. The IC50 value for d-Ara was estimated to be 7.5mM, which surpassed that of the potent glycolytic inhibitor 2-deoxy-d-glucose (19.5mM) used as a positive control. The inhibitory effect of d-Ara was also observed in animals cultured in axenic conditions using a chemically defined medium; this excluded the possible influence of E. coli. To our knowledge, this is the first report of biological activity of d-Ara. The d-Ara-induced inhibition was recovered by adding either d-ribose or d-fructose, but not d-glucose. These findings suggest that the inhibition could be induced by multiple mechanisms, for example, disturbance of d-ribose and d-fructose metabolism.

Yoshihara A et al. (2019) Bioorg Med Chem Lett "Growth inhibition by 1-deoxy-d-allulose, a novel bioactive deoxy sugar, screened using Caenorhabditis elegans assay."

Sakoguchi H, Fleet GWJ, Izumori K, Shintani T, Sato M, Yoshihara A

[Bioorg Med Chem Lett, 2019]

The biological activities of deoxy sugars (deoxy monosaccharides) have remained largely unstudied until recently. We compared the growth inhibition by all 1-deoxyketohexoses using the animal model Caenorhabditis elegans. Among the eight stereoisomers, 1-deoxy-d-allulose (1d-d-Alu) showed particularly strong growth inhibition. The 50% inhibition of growth (GI₅₀) concentration by 1d-d-Alu was estimated to be 5.4mM, which is approximately 10 times lower than that of d-allulose (52.7mM), and even lower than that of the potent glycolytic inhibitor, 2-deoxy-d-glucose (19.5mM), implying that 1d-d-Alu has a strong growth inhibition. In contrast, 5-deoxy- and 6-deoxy-d-allulose showed no growth inhibition of C. elegans. The inhibition by 1d-d-Alu was alleviated by the addition of d-ribose or d-fructose. Our findings suggest that 1d-d-Alu-mediated growth inhibition could be induced by the imbalance in d-ribose metabolism. To our knowledge, this is the first report of biological activity of 1d-d-Alu which may be considered as an antimetabolite drug candidate.

Katane M et al. (2020) Biochim Biophys Acta Proteins Proteom "Biochemical characterization of d-aspartate oxidase from Caenorhabditis elegans: Its potential use in the determination of free D-glutamate in biological samples."

Katane M, Sekine M, Nakayama K, Homma H, Kuwabara H, Saitoh Y, Miyamoto T

[Biochim Biophys Acta Proteins Proteom, 2020]

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). Mammalian DDO, which exhibits higher activity toward d-aspartate than D-glutamate, is presumed to regulate levels of d-aspartate in the body and is not thought to degrade D-glutamate in vivo. By contrast, three DDO isoforms are present in the nematode Caenorhabditis elegans, DDO-1, DDO-2, and DDO-3, all of which exhibit substantial activity toward D-glutamate as well as d-aspartate. In this study, we optimized the Escherichia coli culture conditions for production of recombinant C. elegans DDO-1, purified the protein, and showed that it is a flavoprotein with a noncovalently but tightly attached FAD. Furthermore, C. elegans DDO-1, but not mammalian (rat) DDO, efficiently and selectively degraded D-glutamate in addition to d-aspartate, even in the presence of various other amino acids. Thus, C. elegans DDO-1 might be a useful tool for determining these acidic D-amino acids in biological samples.

Shintani T et al. (2019) J Appl Glycosci (1999) "D-Allose, a Stereoisomer of D-Glucose, Extends the Lifespan of Caenorhabditis elegans via Sirtuin and Insulin Signaling."

Izumori K, Sakoguchi H, Yoshihara A, Shintani T, Sato M

[J Appl Glycosci (1999), 2019]

D-Allose (D-All), C-3 epimer of D-glucose, is a rare sugar known to suppress reactive oxygen species generation and prevent hypertension. We previously reported that D-allulose, a structural isomer of D-All, prolongs the lifespan of the nematode Caenorhabditis elegans. Thus, D-All was predicted to affect longevity. In this study, we provide the first empirical evidence that D-All extends the lifespan of C. elegans. Lifespan assays revealed that a lifespan extension was induced by 28 mM D-All. In particular, a lifespan extension of 23.8 % was achieved (p< 0.0001). We further revealed that the effects of D-All on lifespan were dependent on the insulin gene daf-16 and the longevity gene sir-2.1, indicating a distinct mechanism from those of other hexoses, such as D-allulose, with previously reported antiaging effects.

Sato M et al. (2008) J Nat Med "Potential anthelmintic: D-psicose inhibits motility, growth and reproductive maturity of L1 larvae of Caenorhabditis elegans."

Izumori K, Yamasaki T, Kurose H, Sato M

[J Nat Med, 2008]

No anthelmintic sugars have yet been identified. Eight ketohexose stereoisomers (D- and L-forms of psicose, fructose, tagatose and sorbose), along with D-galactose and D-glucose, were examined for potency against L1 stage Caenorhabditis elegans fed Escherichia coli. Of the sugars, D-psicose specifically inhibited the motility, growth and reproductive maturity of the L1 stage. D-Psicose probably interferes with the nematode nutrition. The present results suggest that D-psicose, one of the rare sugars, is a potential anthelmintic.

Yasuaki Saitoh et al. (2010) East Asia Worm Meeting "Study on physiological functions of D-amino acid degradative enzymes in nematode Caenorhabditis elegans"

Yousuke Seida, Kazuhiro Maeda, Tomonori Kawata, Masumi Katane, Hiroyuki Kobuna, Takao Inoue, Yasuaki Saitoh, Hiroyuki Arai, Yasuhito Nakagawa, Masae Sekine, Taro Sakamoto, Hiroshi Homma, Takemitsu Furuchi

[East Asia Worm Meeting, 2010]

Among free D-amino acids existing in living organisms, D-serine (D-Ser) and D-aspartate (D-Asp) are the most actively studied. D-Ser has been proposed as a neuromodulator that regulates L-glutamate-mediated activation of the N-methyl-D-Asp (NMDA) receptor by acting as a co-agonist. On the other hand, several lines of evidence suggest that D-Asp plays important roles in regulating developmental processes, hormone secretion and steroidogenesis. D-Amino acid oxidase (DAO) and D-Asp oxidase (DDO) are known as stereospecific degradative enzymes that catalyze the oxidative deamination of D-amino acids. DAO displays broad substrate specificity and acts on several neutral and basic D-amino acids, while DDO is highly specific for acidic D-amino acids. DAO and DDO are presumed to regulate endogenous D-Ser and D-Asp levels, respectively, as well as mediate the elimination of accumulated exogenous D-amino acids in various organs. Previously, we demonstrated that nematode Caenorhabditis elegans, a multicellular model animal has at least one active DAO gene and three active DDO genes, while it had been thought that most organisms bear only one copy of each DAO and DDO gene. In addition, our previous study revealed that the spatiotemporal distributions of these enzymes in the body of C. elegans are different from one another. In this study, to elucidate the physiological roles of the C. elegans DAO and DDOs, we characterized several phenotypes of four C. elegans mutants in which each gene is partially deleted and inactivated. We also determined free D-amino acid contents in several worm samples using high-performance liquid chromatography (HPLC) techniques. We will report the phenotypes of the C. elegans mutants in comparison with those of wild-type C. elegans, as well as alterations in D-amino acid levels within the body.