METHYLMERCURY EXTRACTION FROM ARTIFICIAL SEDIMENTS BY THE GUT JUICE OF THE SIPUNCULAN, SIPUNCULUS NUDUS

2008 ◽  
Vol 27 (1) ◽  
pp. 138 ◽  
Author(s):  
Huan Zhong ◽  
Wen-Xiong Wang
Keyword(s):  
Sipunculus Nudus ◽  
Artificial Sediments

Microscopic and ultrastructural observations of embryonic and larval development in Sipunculus nudus

2018 ◽  
Vol 25 (5) ◽  
pp. 976 ◽  
Author(s):  
Jiawei ZHANG ◽  
Ruijuan HAO ◽  
Qingheng WANG ◽  
Chuangye YANG ◽  
Xiaodong DU ◽  
...  
Keyword(s):  
Larval Development ◽  
Sipunculus Nudus ◽  
Embryonic And Larval Development

scholarly journals Proton-Equivalent Ion Transfer in Sipunculus Nudus as a Function of Ambient Oxygen Tension: Relationships with Energy Metabolism

1991 ◽  
Vol 156 (1) ◽  
pp. 21-39 ◽  
Author(s):  
H. O. PÖRTNER ◽  
N. A. ANDERSEN ◽  
N. HEISLER
Keyword(s):  
Recovery Period ◽  
Environmental Water ◽  
Body Fluids ◽  
The Body ◽  
Ion Transfer ◽  
Available Energy ◽  
Base Parameters ◽  
Sipunculus Nudus ◽  
Ambient Oxygen ◽  
Translocation Mechanism

Proton-equivalent ion transfer processes between animals and ambient water were determined under normoxic control conditions during anaerobiosis and the subsequent recovery period in the marine worm Sipunculus nudus L. During anaerobiosis and recovery, transepithelial H+-equivalent ion transfer was generally correlated with changes in extracellular pH, with some disparities in ‘spring’ animals. The typical initial alkalosis induced by phosphagen cleavage during early anaerobiosis was reflected by a loss of basic equivalents. The acidosis, which developed later, reflecting production of acidic metabolic intermediates, resulted in a relatively small net extrusion of protons into the water. The coelomic acidosis during recovery was greatly exaggerated by the release of protons during phosphagen repletion and by the considerable elevation of Pco2 after normoxia had been reattained. The acidosis stimulated the net release of H+ to the water at a rate several times higher than that during anaerobiosis. The efficient transfer of protons from the body fluids to the environmental water during recovery facilitated normalization of coelomic pH, long before protons dissociated from the large amounts of organic acids produced as anaerobic intermediates could be removed from the body fluids by metabolism. Although the transfer of net H+ equivalents to the water coincided with coelomic acidosis, the rates of transfer during different periods of the experiment were primarily correlated with overall metabolic rate. Low net proton transfer rates associated with anaerobiosis were not sufficient to maintain acid-base parameters typical for normoxia, whereas re-establishment of aerobic conditions facilitated a greatly increased transepithelial H+ transfer rate. These data suggest that the transfer capacity of the energy-consuming translocation mechanism may primarily be determined by the rate of metabolic turnover and, accordingly, by theamount of available energy.

scholarly journals Modulation of the cost of pHi regulation during metabolic depression: a (31)P-NMR study in invertebrate (Sipunculus nudus) isolated muscle

2000 ◽  
Vol 203 (16) ◽  
pp. 2417-2428 ◽  
Author(s):  
H.O. Portner ◽  
C. Bock ◽  
A. Reipschlager
Keyword(s):  
Steady State ◽  
Marine Invertebrate ◽  
Metabolic Depression ◽  
Acid Base ◽  
Extracellular Acidosis ◽  
Nmr Study ◽  
Sipunculus Nudus ◽  
Delayed Recovery ◽  
Dimethyl Amiloride

Extracellular acidosis has been demonstrated to play a key role in the process of metabolic depression under long-term environmental stress, exemplified in the marine invertebrate Sipunculus nudus. These findings led to the hypothesis that acid-base regulation is associated with a visible cost depending on the rate and mode of H(+)-equivalent ion exchange. To test this hypothesis, the effects of different ion-transport inhibitors on the rate of pH recovery during hypercapnia, on energy turnover and on steady-state acid-base variables were studied in isolated body wall musculature of the marine worm Sipunculus nudus under control conditions (pHe 7.90) and during steady-state extracellular acidosis (pHe 7.50 or 7.20) by in vivo (31)P-NMR and oxygen consumption analyses. During acute hypercapnia (2 % CO(2)), recovery of pHi was delayed at pHe 7.5 compared with pHe 7.9. Inhibition of the Na(+)/H(+)-exchanger by 5-(N,N-dimethyl)-amiloride (DMA) at pHe 7.5 delayed recovery even further. This effect was much smaller at pHe 7.9. Inhibition of anion exchange by the addition of the transport inhibitor 4, 4′-diisothiocyanatostilbene-2,2′-disulphonic acid (DIDS) prevented pH recovery at pHe 7.5 and delayed recovery at pHe 7.9, in accordance with an effect on Na(+)-dependent Cl(−)/HCO(3)(−) exchange. The effects of ouabain, DIDS and DMA on metabolic rate were reduced at low pHe, thereby supporting the conclusion that acidosis caused the ATP demand of Na(+)/K(+)-ATPase to fall. This reduction occurred via an inhibiting effect on both Na(+)/H(+)- and Na(+)-dependent Cl(−)/HCO(3)(−) (i.e. Na(+)/H(+)/Cl(−)/HCO(3)(−)) exchange in accordance with a reduction in the ATP demand for acid-base regulation during metabolic depression. Considering the ATP stoichiometries of the two exchangers, metabolic depression may be supported by the predominant use of Na(+)/H(+)/Cl(−)/HCO(3)(−) exchange under conditions of extracellular acidosis.

scholarly journals A role for adenosine in metabolic depression in the marine invertebrate Sipunculus nudus

1997 ◽  
Vol 272 (1) ◽  
pp. R350-R356 ◽  
Author(s):  
A. Reipschlager ◽  
G. E. Nilsson ◽  
H. O. Portner
Keyword(s):  
Body Wall ◽  
Marine Invertebrate ◽  
Coelomic Fluid ◽  
Metabolic Depression ◽  
O2 Consumption ◽  
Experimental Conditions ◽  
Indwelling Catheter ◽  
Sipunculus Nudus ◽  
Body Wall Musculature ◽  
Concentration Changes

Involvement of neurotransmitters in metabolic depression under hypoxia and hypercapnia was examined in Sipunculus nudus. Concentration changes of several putative neurotransmitters in nervous tissue during anoxic or hypercapnic exposure or during combined anoxia and hypercapnia were determined. Among amino acids (gamma-aminobutyric acid, glutamate, glycine, taurine, serine, and aspartate) and monoamines (serotonin, dopamine, and norepinephrine), some changes were significant, but none were consistent with metabolic depression under all experimental conditions applied. Only the neuromodulator adenosine displayed concentration changes in accordance with metabolic depression under all experimental conditions. Levels increased during anoxia, during hypercapnia, and to an even greater extent during anoxic hypercapnia. Adenosine infusions into coelomic fluid via an indwelling catheter induced a significant depression of the normocapnic rate of O2 consumption from 0.36 +/- 0.04 to a minimum of 0.24 +/- 0.02 (SE) mumol.g-1.h-1 after 90 min (n = 6). Application of the adenosine antagonist theophylline caused a transient rise in O2 consumption 30 min after infusion during hypercapnia but not during normocapnia. Effects of adenosine and theophylline were observed in intact individuals but not in isolated body wall musculature. The results provide evidence for a role of adenosine in inducing metabolic depression in S. nudus, probably through the established effects of decreasing neuronal excitability and neurotransmitter release. In consideration of our previous finding that metabolic depression in isolated body wall musculature was elicited by extracellular acidosis, it is concluded that central and cellular mechanisms combine to contribute to the overall reduction in metabolic rate in S. nudus.

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