Studies on the role of ornithine cycle and purine catabolism in urea biosynthesis in the fresh-water crayfish, Orconectes rusticus

Sharma, Moti L.; Neveu, Maurice C.

doi:10.1016/0305-0491(71)90032-0

Cited by 5 publications

(1 citation statement)

References 9 publications

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“…The enzymes involved in uricolysis are uricase, allantoinase and allantoicase, which complete the breakdown of uric acid. Uricase and XDH activity has been detected in several species of aquatic crustacean including Carcinus maenas (Dykens 1991), freshwater crayfish Orconectes rusticus (Sharma & Neveu 1971), land crab Gecarcinus natalis (Linton & Greenaway 1998) and Kuruma shrimp Marsupenaeus japonicus (Cheng et al 2004), indicating that they are capable of producing uric acid and urea via the purine nucleotide and uricolytic pathways. Uricase activity was not measured during this investigation, but XDH activity was detected, and the presence of small quantities of uric acid and significantly larger concentrations of urea indicate that uricase activity is probably present in Nephrops norvegicus and raises the possibility that N. norvegicus is also capable of utilising the purine nucleotide and urciolytic pathways.…”

Section: Discussionmentioning

confidence: 99%

Purineolytic capacity response of Nephrops norvegicus to prolonged emersion: an ammonia detoxification process

Bernasconi¹,

Uglow²

2011

Aquat. Biol.

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Under prolonged (> 24 h) emersion, Norway lobster Nephrops norvegicus changed purineolytic pathways in response to increased levels of circulating ammonia. Haemolymph levels of urea and uric acid more than doubled during emersion, but xanthine oxidase was not detected, even after 72 h emersion. Xanthine dehydrogenase (XDH) was the only form of xanthine oxidoreductase detected, so the metabolic costs of producing uric acid would have been relatively small. Although ammonia, urea, uric acid and XDH all accumulated in the haemolymph during emersion, the relative proportions of ammonia and urea stayed the same at all times, which suggests the presence of enzymes from the uricolyic pathway (e.g. uricase and urease). Supranormal ammonia effluxes occurred almost immediately following re-immersion in amounts that indicate a high degree of hypoxia tolerance under emersion and that this is negatively related with the prevailing temperature. We conclude that N. norvegicus has purineolytic capacity and, under prolonged hypoxia, produces purines de novo as an ammonia-detoxification strategy that has probable survival value for a benthic burrowing species that may experience periods of severe hypoxia.

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Section: Discussionmentioning

confidence: 99%

Purineolytic capacity response of Nephrops norvegicus to prolonged emersion: an ammonia detoxification process

Bernasconi¹,

Uglow²

2011

Aquat. Biol.

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Increased Production and Excretion of Urea in the Kuruma Shrimp (Marsupenaeus japonicus) Exposed to Combined Environments of Increased Ammonia and Nitrite

Cheng

Lee

Shieh

et al. 2004

Arch Environ Contam Toxicol

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Marsupenaeus japonicus (6.37 +/- 1.29 g) individually exposed to 9 different combined solutions of ambient ammonia (C) and nitrite (C') ammonia at 0.003 [control], 0.39, and 1.49 mmol/L combined with nitrite at 0.001 [control], 0.38, and 1.49 mmol/L in 30 ppt were examined for nitrogenous excretion accumulations of ammonia, nitrite, urea, and uric acid in tissues after 48 hours. M. japonicus exposed to 0.39 mmol/L ammonia-0.38 mmol/L nitrite displayed higher levels of urea-nitrogen (UNE) and organic-N (ONE) excretion by a factor of 2.2 and 5.7, respectively, compared with shrimp exposed only to 0.39 mmol/L ammonia. Exposure to 0.39 mmol/L ammonia-0.38 mmol/L nitrite resulted in lower levels of hemolymph uric acid (HUA), gill ammonia (GAM), gill urea (GUE), gill uric acid (GUA), hepatopancreas ammonia (HPAM), hepatopancreas urea (HPUE), and hepatopancreas uric acid (APUA), respectively, compared with shrimp exposed only to 0.39 mmol/L ammonia. We concluded that M. japonicus exposed to combined environments of ammonia and nitrite display increased nitrogen metabolism and production of urea-N and other organic-N.

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Nitrogen Metabolism

Claybrook¹

1983

Internal Anatomy and Physiological Regulation

102

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Studies on the role of ornithine cycle and purine catabolism in urea biosynthesis in the fresh-water crayfish, Orconectes rusticus

Cited by 5 publications

References 9 publications

Purineolytic capacity response of Nephrops norvegicus to prolonged emersion: an ammonia detoxification process

Purineolytic capacity response of Nephrops norvegicus to prolonged emersion: an ammonia detoxification process

Increased Production and Excretion of Urea in the Kuruma Shrimp (Marsupenaeus japonicus) Exposed to Combined Environments of Increased Ammonia and Nitrite

Nitrogen Metabolism

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