Reddy AB et al. (1984) J Helminthol "Microfilarial periodicity in Mastomys natalensis."

Rao UR, Subrahmanyam D, Reddy AB, Chandrashekar R

[J Helminthol, 1984]

The microfilarial level in the peripheral blood of Mastomys natalensis infected with the filarial parasites, Litomosoides carinii, Brugia pahangi, B. malayi and Dipetalonema viteae was monitored at two-hour intervals for 24 hours. The microfilariae of B. pahangi and B. malayi exhibited nocturnal and diurnal subperiodicity, respectively; no such periodicity was seen in L. carinii and D. viteae infections. The level of B. pahangi and D. viteae microfilariae in peripheral blood was significantly increased when the host was anaesthetized with diethylether or pentothal sodium. Ether-induced anaesthesia had no effect on the level of B. malayi microfilariae but pentothal was most effective. The peripheral blood count of L. carinii microfilariae tended to decrease in the anaesthetized animals but the reduction was not statistically significant.

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."

Sato M, Sakoguchi H, Yoshihara A, Izumori K

[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, Yoshihara A, Sato M, Izumori K, Okuma K, Sakoguchi H

[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.

Chandrashekar R et al. (1990) Int J Parasitol "Antibody-mediated cytotoxic effects in vitro and in vivo of rat cells on infective larvae of Brugia malayi."

Chandrashekar R, Rao UR, Subrahmanyam D

[Int J Parasitol, 1990]

Albino rat macrophages and neutrophils in the presence of immune serum adhered to and promoted killing of Brugia malayi infective larvae in vitro. At a similar cell-target ratio, macrophages were more potent than neutrophils in inducing cytotoxic response to the larvae. Eosinophils were also effective in killing but only at a high cell-target ratio. The activity in the immune serum could be absorbed to and eluted from a Protein A-Sepharose column suggesting involvement of IgG antibody in the reaction. An indirect fluorescent antibody test confirmed the presence of IgG on the surface of larvae incubated in immune serum. Infective larvae were attacked by host cells within micropore chambers 16-24 h after implantation into immunized rats. Further, a strong cytotoxic response to the larvae was seen when they were introduced intraperitoneally into immune rats indicating the role of antibody and cells in vivo. We suggest that antibody-dependent cellular cytotoxicity may represent an important mechanism of parasite killing in an immune host.

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."

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

[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.

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."

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

[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.

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

[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."

Kurose H, Izumori K, Yamasaki T, 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.

Chandrashekar R et al. (1986) Exp Parasitol "Brugia malayi: rat cell interactions with infective larvae mediated by complement."

Parab PB, Rao UR, Chandrashekar R, Subrahmanyam D

[Exp Parasitol, 1986]

Albino rat macrophages and neutrophils, in the presence of fresh normal rat serum as a source of complement, adhered to and promoted killing of Brugia malayi infective larvae in vitro. Eosinophils, by themselves, were marginally cytotoxic at a high cell-target ratio but promoted cytotoxicity when mixed with macrophages. Eosinophil culture supernatants enhanced the macrophage mediated killing of infective larvae. The complement of fresh normal rat serum was found to act by the alternate pathway. Fresh normal rat serum depleted of alternate pathway complement activity by treatment with zymosan A, or of Factor B by heating at 50 C for 20 min, or of Factor D by passing through Sephadex G75 column, failed to promote cell adherence to the parasite. C3 molecules were detected on the surface of infective larvae by immunofluorescence. There was a significant consumption of complement when Brugia malayi infective larvae were incubated in fresh normal rat serum. Albino rat cells were more potent in inducing cytotoxicity to infective larvae in vitro than those from jird or Mastomys natalensis, which may reflect the greater resistance offered by the rat to B. malayi infection. There was much less cellular infiltration on introduction of Brugia malayi infective larvae into the peritoneal cavity of jirds compared to rats and Mastomys natalensis indicating the greater susceptibility of jirds to intraperitoneally induced infections.

Saitoh, Yasuaki et al. (2013) International Worm Meeting "D-Aspartate oxidase is involved in the caloric restriction-induced lifespan extension in C. elegans."

Arai, Hiroyuki, Furuchi, Takemitsu, Okutsu, Mari, Homma, Hiroshi, Saitoh, Yasuaki, Katane, Masumi, Inoue, Takao, Sekine, Masae, Sakamoto, Taro

[International Worm Meeting, 2013]

Among free D-amino acids existing in living organisms, D-serine (D-Ser) and D-aspartate (D-Asp) are the most intensively studied. In mammals, D-Ser has been proposed as a neuromodulator that regulates L-glutamate (L-Glu)-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 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. Mammalian DAO and DDO are presumed to regulate endogenous D-Ser and D-Asp levels, respectively. Previously, we demonstrated that D-Ser, D-Asp, D-Glu and D-alanine (D-Ala) are present in nematode Caenorhabditis elegans, a multicellular model animal. We also found that C. elegans has at least one active DAO gene and three active DDO genes (DDO-1, DDO-2 and DDO-3), and that the spatiotemporal distributions of these enzymes in the body of C. elegans differ from one another. Furthermore, our previous study showed that alterations of brood size and hatching rate are observed in four C. elegans mutants lacking each gene for the DAO and DDOs. Interestingly, lifespan extension was observed in the DDO-3 mutant. To characterize the mechanism of lifespan extension in the DDO-3 mutant, we performed genetic epistasis experiments to test interactions between the DDO-3 gene and other known longevity pathways. The results suggest that DDO-3 is involved in caloric restriction-induced lifespan extension but not in insulin/IGF signaling pathway, NAD/sir2 pathway nor mitochondrial electron transport system. We also found that D-Glu and L-tryptophan (L-Trp) accumulate throughout life in the DDO-3 mutant. Now we are investigating the relationship between aging and the accumulations of D-Glu and L-Trp.