Seasonal variation in glucose and neutral amino acid uptake in the estuarine crab Neohelice granulata

Valle, Sandra Costa; Eichler, Paula; Maciel, Jose Eduardo Salazar; Machado, Gabriel Santana; Kucharski, Luiz Carlos; Silva, Roselis Silveira Martins da

doi:10.1016/j.cbpa.2009.02.033

Cited by 9 publications

(6 citation statements)

References 35 publications

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“…In vitro experiments carried out with N. granulata from other geographical areas show the de novo synthesis of glycogen in posterior gills via uptake of glucose from the incubation medium (Kucharski et al, 2002) and suggest that adjustments in the uptake of glucose by posterior gills could be a strategy to support the varying environmental conditions in its natural habitat (Valle et al, 2009). The fact that maltase activity was similar in the hepatopancreas of crabs acclimated to 35 and 10 psu (contrary to our prediction) could indicate that the level of this activity is high enough to support a complete hydrolysis of starch.…”

Section: Discussionmentioning

confidence: 99%

Amylase, maltase and sucrase activities in hepatopancreas of the euryhaline crab <i>Neohelice granulata</i> (Decapoda: Brachyura: Varunidae): partial characterization and response to low environmental salinity

Asaro¹,

Valle²,

Mañanes³

2011

Sci. Mar.

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Studies on digestive adjustments at the biochemical level in relation to salinity in euryhaline crabs are lacking. Moreover, knowledge of biochemical digestive characteristics of euryhaline crabs (i.e. occurrence and characteristics of key digestive enzyme activities) is still scarce and fragmentary. We studied the occurrence, characteristics and response to low salinity of amylase, maltase and sucrase activities in the hepatopancreas of the euryhaline crab Neohelice (Chasmagnathus) granulata. Maximal amylase and maltase activities were found at pH 5.2. Sucrase activity was maximal within the pH range 3.6-5.2. Amylase, maltase and sucrase activities showed a Michaelis-Menten kinetics (km = 0.41±0.10 mg ml-1 ; 1.37±1.03 mM and 0.55±0.45 mM, respectively). In crabs acclimated to low salinity (10 psu; hyperregulating conditions), amylase activity (7263±980 µg maltose min-1 mg prot-1) was higher than in 35 psu (osmoconforming conditions) (3605±340 µg maltose min-1 mg prot-1). Maltase and sucrase activities (497±98 and 64±16 µg glucose min-1 mg prot-1 , respectively) were similar in both salinities. The response of amylase activity to low salinity suggests a role in digestive adjustments upon hyperregulation. This study contributes to a better understanding of the complexity of the biochemical adaptations to low salinity in euryhaline crabs.

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Section: Discussionmentioning

confidence: 99%

Amylase, maltase and sucrase activities in hepatopancreas of the euryhaline crab <i>Neohelice granulata</i> (Decapoda: Brachyura: Varunidae): partial characterization and response to low environmental salinity

Asaro¹,

Valle²,

Mañanes³

2011

Sci. Mar.

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“…The additional amylase form in the hepatopancreas of N. granulata at low salinity could be associated with a differential digestive capacity for glycogenic substrates, which would lead to modifications in glucose availability. In vitro experiments with N. granulata from other geographical areas showed the de novo synthesis of glycogen in posterior gills via uptake of glucose and suggested that adjustments in this uptake could be a strategy to support varying environmental conditions (Kucharski et al, 2002;Valle et al, 2009). Hyper-and hypoosmoregulation in crabs appear to require different mechanisms (McNamara and Faria, 2012;Romano and Zeng, 2012).…”

Section: Discussionmentioning

confidence: 99%

Amylase in the hepatopancreas of a euryhaline burrowingcrab: characteristics and modulation

Asaro¹,

Paggi²,

Castro³

et al. 2017

Turk J Zool

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In spite of its inherent physiological importance, studies on the occurrence, characteristics, and modulation of amylase in euryhaline crabs are lacking. We investigated the occurrence of amylase forms and the effect of acclimation to different salinities on their number and made a partial purification and characterization of the major form present in the hepatopancreas of Neohelice granulata. Zymogram analysis revealed 5 amylase forms in crabs acclimated to 35 psu (seawater) and 37 psu, and an additional band at 10 psu, but with a major form (29 kDa) in all cases, which was partially purified and characterized. Amylolytic activity was maximal between 30 and 40 °C; maintained at high NaCl concentrations (up to 4 M); increased by 5 mM K + , Li + , Co 2+ , and Mg 2+ (36%-45%); inhibited by Cu 2+ , Zn 2+ , Cd 2+ , Fe 2+ , and Mn 2+ (92.4% and 23.7%); not affected by Ni 2+ or Ba 2+ ; and enhanced almost 100% by Ca 2+ . Amylase exhibited Michaelis-Menten kinetics (starch: K m = 1.24 mg mL -1 ; glycogen: K m = 16.19 mg mL -1 ). The potential physiological significance and relationship to habitat conditions of the extra form in low salinity and the biochemical characteristics of the partially purified amylolytic activity (halotolerant, differential sensitivity to ions, capability to hydrolyze starch and glycogen) are discussed.

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“…However, the relatively conserved mechanisms of uptake between invertebrate systems studied to date and mammalian amino acid transport [6,20,21] suggests that the transport specificities of mammalian amino acid transport systems could be used to identify the putative L-leucine transporters in C. maenas. In mammals, L-leucine is transported via one of four solute carrier systems [15]. System y þ L is a Na þ -dependent antiporter, and in addition to L-leucine, also transports L-lysine.…”

Section: (B) Delineating the Amino Acid Transportermentioning

confidence: 99%

“…tissue accumulation was measured. However, due to limitations in the methodological approach used, it was unable to be determined if transport was occurring or if the accumulation was non-specific and resulted from isotope trapped in the tissue after being bathed in isotope solution [15]. Therefore, the hypothesis that the gills of crabs transport amino acids has not been adequately tested.…”

Section: Introductionmentioning

confidence: 99%

A novel pathway of nutrient absorption in crustaceans: branchial amino acid uptake in the green shore crab ( Carcinus maenas )

Blewett

Goss

2017

Proc. R. Soc. B.

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Estuaries are environments enriched with dissolved nutrients such as amino acids. To date, marine arthropods are the only invertebrate group that have not been demonstrated to access this potentially important nutrient resource. Using gill perfusion techniques, we sought to investigate the ability of the green shore crab () to take up the amino acid l-leucine directly from the water. Investigation of the concentration-dependent transport kinetics of radiolabelled l-leucine showed that there are two specific transport pathways across gills, one with high affinity and low capacity, and the other with high capacity and low affinity. Using putative competitive substrates and reduced sodium preparations, we were able to identify the putative amino acid transport system associated with high-affinity uptake. This is the first study to demonstrate the absorption of dissolved organic nutrients across the gill epithelium of a marine arthropod.

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Seasonal variation in glucose and neutral amino acid uptake in the estuarine crab Neohelice granulata

Cited by 9 publications

References 35 publications

Amylase, maltase and sucrase activities in hepatopancreas of the euryhaline crab <i>Neohelice granulata</i> (Decapoda: Brachyura: Varunidae): partial characterization and response to low environmental salinity

Amylase, maltase and sucrase activities in hepatopancreas of the euryhaline crab <i>Neohelice granulata</i> (Decapoda: Brachyura: Varunidae): partial characterization and response to low environmental salinity

Amylase in the hepatopancreas of a euryhaline burrowingcrab: characteristics and modulation

A novel pathway of nutrient absorption in crustaceans: branchial amino acid uptake in the green shore crab ( Carcinus maenas )

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