Metabolic importance of Na+/K+-ATPase activity during sea urchin development.

1997 ◽  
Vol 200 (22) ◽  
pp. 2881-2892 ◽  
Author(s):  
P Leong ◽  
D Manahan
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Sea Urchin ◽  
Sodium Pump ◽  
Sea Water ◽  
Strongylocentrotus Purpuratus ◽  
Lytechinus Pictus ◽  
Stimulation Of

Early stages of animal development have high mass-specific rates of metabolism. The biochemical processes that establish metabolic rate and how these processes change during development are not understood. In this study, changes in Na+/K+-ATPase activity (the sodium pump) and rate of oxygen consumption were measured during embryonic and early larval development for two species of sea urchin, Strongylocentrotus purpuratus and Lytechinus pictus. Total (in vitro) Na+/K+-ATPase activity increased during development and could potentially account for up to 77 % of larval oxygen consumption in Strongylocentrotus purpuratus (pluteus stage) and 80 % in Lytechinus pictus (prism stage). The critical issue was addressed of what percentage of total enzyme activity is physiologically active in living embryos and larvae and thus what percentage of metabolism is established by the activity of the sodium pump during development. Early developmental stages of sea urchins are ideal for understanding the in vivo metabolic importance of Na+/K+-ATPase because of their small size and high permeability to radioactive tracers (86Rb+) added to sea water. A comparison of total and in vivo Na+/K+-ATPase activities revealed that approximately half of the total activity was utilized in vivo. The remainder represented a functionally active reserve that was subject to regulation, as verified by stimulation of in vivo Na+/K+-ATPase activity in the presence of the ionophore monensin. In the presence of monensin, in vivo Na+/K+-ATPase activities in embryos of S. purpuratus increased to 94 % of the maximum enzyme activity measured in vitro. Stimulation of in vivo Na+/K+-ATPase activity was also observed in the presence of dissolved alanine, presumably due to the requirement to remove the additional intracellular Na+ that was cotransported with alanine from sea water. The metabolic cost of maintaining the ionic balance was found to be high, with this process alone accounting for 40 % of the metabolic rate of sea urchin larvae (based on the measured fraction of total Na+/K+-ATPase that is physiologically active in larvae of S. purpuratus). Ontogenetic changes in pump activity and environmentally induced regulation of reserve Na+/K+-ATPase activity are important factors that determine a major proportion of the metabolic costs of sea urchin development.

The relationship between Mg2+-stimulated ATPase activity and glycogen content in rat liver

1969 ◽  
Vol 47 (3) ◽  
pp. 339-345 ◽  
Author(s):  
B. Rubenstein ◽  
P. G. Scholefield
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Rat Liver ◽  
Glycogen Content ◽  
Phosphorylase Activity ◽  
Tumor Bearing ◽  
Physical Association ◽  
The Relationship

During starvation there is an increase in the ATPase activity of a postmitochondrial fraction of rat liver. The increase is relatively specific for ATP and there is no change in the Na+,K+-stimulated ATPase activity. A corresponding increase in ATPase activity is found on pretreatment of the rat with glucagon and in tumor-bearing animals. The increase has been correlated with increase in phosphorylase activity and decrease in glycogen content under in vivo and in vitro conditions. Treatment of fasted animals with glucose or sucrose restores the glycogen content and diminishes the ATPase activity to normal levels, but puromycin is without effect. It is proposed that a physical association of glycogen with Mg2+-stimulated ATPase activity prevents the enzyme activity from being expressed.

scholarly journals Na+/K+-ATPase activity during early development and growth of an Antarctic sea urchin

1999 ◽  
Vol 202 (15) ◽  
pp. 2051-2058 ◽  
Author(s):  
P.K. Leong ◽  
D.T. Manahan
Keyword(s):  
Atpase Activity ◽  
Sea Urchin ◽  
Developmental Stages ◽  
Lytechinus Pictus ◽  
Cold Environments ◽  
Total Potential ◽  
Rate Of Increase ◽  
Development Accounting ◽  
Limited Food

In Antarctic environments, the physiological bases for long larval life spans under natural conditions of limited food availability are not understood. The Na+ pump is likely to be involved with hypometabolic regulation in such cold environments. Changes in the activity and metabolic importance of Na+/K+-ATPase were measured in embryos of the Antarctic sea urchin Sterechinus neumayeri and in larvae reared under different feeding conditions. The rate of increase of total Na+/K+-ATPase activity was 3.9 times faster in fed than in unfed larvae. During development and growth, there was an increase in the percentage of total, potential Na+/K+-ATPase activity that was physiologically utilized. In early (10-day-old) gastrulae, 17 % was utilized in vivo, increasing to 77 % in six-arm pluteus (48-day-old) larvae. The metabolic importance of in vivo Na+/K+-ATPase activity also increased during development, accounting for 12 % of metabolic rate at day 10 and 84 % at day 48. When compared at the same enzyme assay temperature (15 degrees C), the protein-specific total Na+/K+-ATPase activities for late embryonic (prism) and early larval (pluteus) stages of S. neumayeri were 2.6 times lower than those for comparable developmental stages of two temperate sea urchin species (Strongylocentrotus purpuratus and Lytechinus pictus).

In vitro stimulation of Na-K-ATPase in rat thick ascending limb by dexamethasone

1986 ◽  
Vol 251 (5) ◽  
pp. F851-F857 ◽  
Author(s):  
A. Doucet ◽  
A. Hus-Citharel ◽  
F. Morel
Keyword(s):  
Atpase Activity ◽  
Sodium Reabsorption ◽  
Thick Ascending Limb ◽  
Dependent Manner ◽  
Short Term ◽  
Medullary Thick Ascending Limb ◽  
Dose Dependent ◽  
Stimulation Of

Dexamethasone has been reported to stimulate Na-K-ATPase activity in the medullary thick ascending limb of adrenalectomized animals within a few hours. The present study was aimed at characterizing the mechanism of this action by investigating the stimulatory effect of the hormone in vitro. Dexamethasone (10(-8) M) added in vitro to segments of the medullary thick ascending limb of Henle's loop, which were microdissected from adrenalectomized rats, restored in a dose-dependent manner the depressed Na-K-ATPase activity within one h of incubation. This stimulation of Na-K-ATPase was inhibited by cycloheximide and actinomycin D. Dexamethasone also stimulated the component of oxidative metabolism coupled to sodium transport. These results, which confirm previous in vivo observations, demonstrate that dexamethasone-induced stimulation of Na-K-ATPase is a direct tubular action of the hormone mediated by protein synthesis. They suggest that this short-term effect of dexamethasone corresponds to the stimulation of sodium reabsorption by the dilution segment.

scholarly journals The Effectiveness of Candidate Probiotic Bacteria to Control Vibriosis Disease

2017 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Mulyati Mulyati ◽  
Suryati Suryati ◽  
Irfani Baga
Keyword(s):  
Survival Rate ◽  
Sea Water ◽  
Challenge Test ◽  
Probiotic Bacteria ◽  
Pathogenicity Test ◽  
Inhibitory Ability ◽  
Significant Difference ◽  
Portunid Crab

The study aims to isolate, characterize, and examine probiotic bacteria's inhibitory ability against Vibrio harveyi bacteria, both in-vitro and in vivo. Methods used in the study consist of 1) An Isolation of Candidate Probiotic Bacteria, 2) An Antagonistic Test of Candidate Probiotic Bacteria in vitro, 3) An Identification of Bacteria, 4) A Pathogenicity Test of Candidate Probiotic Bacteria, 5) An Antagonistic Test of Candidate Probiotic Bacteria against V. harveyi in vivo. According to the isolation of candidate probiotic bacteria, there are 18 isolated candidate probiotic. After being tested for its inhibitory ability in vitro, there are 8 isolates with zone of inhibition as follows: isolate MM 7 from intestine (22 mm), isolate MM 6 from intestine (12 mm), isolate MM 10 from sea water (10 mm), isolate MM 5 from intestine (9 mm), isolate MM 4 from intestine (8 mm), isolate MM 3 from intestine (7 mm), isolate MM 2.2 from intestine (7 mm), isolate MM 2.1 from intestine (7 mm). Eight genera of the candidate probiotic bacteria is derived from Portunid crab, they are Staphylococcus, Streptococcus, bacillus, vibrio, Alcaligenes, Lactobacillus, micrococcus. Before proceeding the V. harveyi bacterial challenge test in vivo, three potential isolates consisting of MM6, MM7 and MM10 as the probiotic bacteria are pathogenicity-tested against V. harveyi. The survival rate of Portunid crab on pathogenicity test using MM6, MM7 and MM10 generates 91.11-100%, while the control generates 100% survival rate. Variance analysis result through post-hoc Tukey's Honest Significant Difference (HSD) test at 95% confidence interval indicates that isolate MM7 and MM10 are significantly able to increase hatchling Portunid crab's survival rate.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

scholarly journals Contamination of erythropoietin by endotoxin: in vivo and in vitro effects on murine erythropoiesis

Blood ◽  
1979 ◽  
Vol 54 (1) ◽  
pp. 146-158 ◽  
Author(s):  
KS Zuckerman ◽  
PJ Quesenberry ◽  
J Levin ◽  
R Sullivan
Keyword(s):  
Significant Inhibition ◽  
Erythropoietic Activity ◽  
Limulus Amebocyte Lysate ◽  
Endogenous Erythropoietin ◽  
Significant Change ◽  
In Vitro Effects ◽  
Stimulation Of

Abstract Endotoxin was detected in all erythropoietin preparations tested and was removed from four lots, without loss of erythropoietic activity, by adsorption with limulus amebocyte lysate. Comparison of adsorbed (endotoxin-depleted) and nonadsorbed (endotoxin-containing) erythropoietin preparations demonstrated significant inhibition of CFU- e and BFU-e in vitro by nonadsorbed erythropoietin at concentrations higher than 0.25 U/ml and 2.0 U/ml, respectively. CFU-e and BFU-e were inhibited significantly by readdition in vitro of 10(-5)-10(-3) mug of endotoxin per unit of limulus-adsorbed erythropoietin. Administration of saline or 6 U of nonadsorbed or adsorbed erythropoietin twice a day for 4 days of CF1 mice resulted in reticulocyte counts of 2.1%, 9.9%, and 15.9%, respectively. Nonadsorbed erythropoietin resulted in a 29% decrease in erythropoiesis, a 42% decrease in CFU-e, and a 16% increase in granulopoiesis in the marrow, whereas adsorbed erythropoietin caused a 28% increase in erythropoiesis, no significant change in CFU-e and a 19% decrease in granulopoiesis in the marrow. Both preparations resulted in marked increases in splenic erythropoiesis and granulopoiesis. The effects of adsorbed erythropoietin are similar to those produced following stimulation of hematopoiesis by endogenous erythropoietin. Hemopoietic changes induced by nonadsorbed erythropoietin in vivo and in vitro are affected substantially by contamination of the erythropoietin preparations with endotoxin.

scholarly journals Dissection of Swa2p/Auxilin Domain Requirements for Cochaperoning Hsp70 Clathrin-uncoating Activity In Vivo

2006 ◽  
Vol 17 (7) ◽  
pp. 3281-3290 ◽  
Author(s):  
Jing Xiao ◽  
Leslie S. Kim ◽  
Todd R. Graham
Keyword(s):  
Atpase Activity ◽  
Point Mutation ◽  
Mutational Analysis ◽  
Weak Interactions ◽  
Tetratricopeptide Repeat ◽  
Uba Domain ◽  
J Domain ◽  
Tpr Domain

The auxilin family of J-domain proteins load Hsp70 onto clathrin-coated vesicles (CCVs) to drive uncoating. In vitro, auxilin function requires its ability to bind clathrin and stimulate Hsp70 ATPase activity via its J-domain. To test these requirements in vivo, we performed a mutational analysis of Swa2p, the yeast auxilin ortholog. Swa2p is a modular protein with three N-terminal clathrin-binding (CB) motifs, a ubiquitin association (UBA) domain, a tetratricopeptide repeat (TPR) domain, and a C-terminal J-domain. In vitro, clathrin binding is mediated by multiple weak interactions, but a Swa2p truncation lacking two CB motifs and the UBA domain retains nearly full function in vivo. Deletion of all CB motifs strongly abrogates clathrin disassembly but does not eliminate Swa2p function in vivo. Surprisingly, mutation of the invariant HPD motif within the J-domain to AAA only partially affects Swa2p function. Similarly, a TPR point mutation (G388R) causes a modest phenotype. However, Swa2p function is abolished when these TPR and J mutations are combined. The TPR and J-domains are not functionally redundant because deletion of either domain renders Swa2p nonfunctional. These data suggest that the TPR and J-domains collaborate in a bipartite interaction with Hsp70 to regulate its activity in clathrin disassembly.

Cytasters induced within unfertilized sea-urchin eggs

1983 ◽  
Vol 61 (1) ◽  
pp. 175-189
Author(s):  
R. Kuriyama ◽  
G.G. Borisy
Keyword(s):  
Electron Microscopy ◽  
Sea Urchin ◽  
Sea Water ◽  
Light And Electron Microscopy ◽  
Sea Urchin Eggs ◽  
Microtubule Organizing Centres ◽  
Treatment Step

Conditions that induce the formation of asters in unfertilized sea-urchin eggs have been investigated. Monasters were formed by treatment of eggs with acidic or basic sea-water, or procaine- or thymol-containing sea-water. A second treatment step, incubation with D2O-containing, ethanol-containing or hypertonic sea-water induced multiple cytasters. The number and size of cytasters varied according to the concentration of agents and duration of the first and second treatments, and also upon the species of eggs and the season in which the eggs were obtained. Generally, a longer second treatment or a higher concentration of the second medium resulted in a higher number of cytasters per egg. Asters were isolated and then examined by light and electron microscopy. Isolated monasters apparently lacked centrioles, whereas cytasters obtained from eggs undergoing the two-step treatment contained one or more centrioles. Up to eight centrioles were seen in a single aster; the centrioles appeared to have been produced during the second incubation. Centrospheres prepared from isolated asters retained the capacity to nucleate the formation of microtubules in vitro as assayed by light and electron microscopy. Many microtubules radiated from the centre of isolated asters, whether they contained centrioles or not. This observation is consistent with many other reports that microtubule-organizing centres need not contain centrioles.

Autonomous and non-autonomous differentiation of ectoderm in different sea urchin species

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1497-1505 ◽  
Author(s):  
A.H. Wikramanayake ◽  
B.P. Brandhorst ◽  
W.H. Klein
Keyword(s):  
Sea Urchin ◽  
Strongylocentrotus Purpuratus ◽  
Protein A ◽  
Cellular Interactions ◽  
V Protein ◽  
Lytechinus Pictus ◽  
Sea Urchin Embryo ◽  
Oral Ectoderm ◽  
Temporal And Spatial

During early embryogenesis, the highly regulative sea urchin embryo relies extensively on cell-cell interactions for cellular specification. Here, the role of cellular interactions in the temporal and spatial expression of markers for oral and aboral ectoderm in Strongylocentrotus purpuratus and Lytechinus pictus was investigated. When pairs of mesomeres or animal caps, which are fated to give rise to ectoderm, were isolated and cultured they developed into ciliated embryoids that were morphologically polarized. In animal explants from S. purpuratus, the aboral ectoderm-specific Spec1 gene was activated at the same time as in control embryos and at relatively high levels. The Spec1 protein was restricted to the squamous epithelial cells in the embryoids suggesting that an oral-aboral axis formed and aboral ectoderm differentiation occurred correctly. However, the Ecto V protein, a marker for oral ectoderm differentiation, was detected throughout the embryoid and no stomodeum or ciliary band formed. These results indicated that animal explants from S. purpuratus were autonomous in their ability to form an oral-aboral axis and to differentiate aboral ectoderm, but other aspects of ectoderm differentiation require interaction with vegetal blastomeres. In contrast to S. purpuratus, aboral ectoderm-specific genes were not expressed in animal explants from L. pictus even though the resulting embryoids were morphologically very similar to those of S. purpuratus. Recombination of the explants with vegetal blastomeres or exposure to the vegetalizing agent LiCl restored activity of aboral ectoderm-specific genes, suggesting the requirement of a vegetal induction for differentiation of aboral ectoderm cells.(ABSTRACT TRUNCATED AT 250 WORDS)

UHF-1, a factor required for maximal transcription of early and late sea urchin histone H4 genes: analysis of promoter-binding sites

1991 ◽  
Vol 11 (2) ◽  
pp. 1048-1061
Author(s):  
I J Lee ◽  
L Tung ◽  
D A Bumcrot ◽  
E S Weinberg
Keyword(s):  
Binding Site ◽  
Sea Urchin ◽  
Transcriptional Start Site ◽  
Sodium Dodecyl ◽  
Nuclear Extract ◽  
Dnase I ◽  
Histone H4 ◽  
Band Shift

A protein, denoted UHF-1, was found to bind upstream of the transcriptional start site of both the early and late H4 (EH4 and LH4) histone genes of the sea urchin Strongylocentrotus purpuratus. A nuclear extract from hatching blastulae contained proteins that bind to EH4 and LH4 promoter fragments in a band shift assay and produced sharp DNase I footprints upstream of the EH4 gene (from -133 to -106) and the LH4 gene (from -94 to -66). DNase I footprinting performed in the presence of EH4 and LH4 promoter competitor DNAs indicated that UHF-1 binds more strongly to the EH4 site. A sequence match of 11 of 13 nucleotides was found within the two footprinted regions: [sequence: see text]. Methylation interference and footprinting experiments showed that UHF-1 bound to the two sites somewhat differently. DNA-protein UV cross-linking studies indicated that UHF-1 has an electrophoretic mobility on sodium dodecyl sulfate-acrylamide gels of approximately 85 kDa and suggested that additional proteins, specific to each promoter, bind to each site. In vitro and in vivo assays were used to demonstrate that the UHF-1-binding site is essential for maximal transcription of the H4 genes. Deletion of the EH4 footprinted region resulted in a 3-fold decrease in transcription in a nuclear extract and a 2.6-fold decrease in expression in morulae from templates that had been injected into eggs. In the latter case, deletion of the binding site did not grossly disrupt the temporal program of expression from the injected EH4 genes. LH4 templates containing a 10-bp deletion in the consensus region or base substitutions in the footprinted region were transcribed at 14 to 58% of the level of the wild-type LH4 template. UHF-1 is therefore essential for maximal expression of the early and late H4 genes.

Sign in / Sign up

Export Citation Format

Share Document