Abnormal response to calmodulin in vitro of dystrophic chicken muscle membrane calcium-ATPase activity

Biochemistry ◽  
1988 ◽  
Vol 27 (19) ◽  
pp. 7519-7524 ◽  
Author(s):  
Jose Galindo ◽  
Michael S. Hudecki ◽  
Faith B. Davis ◽  
Paul J. Davis ◽  
Harshad R. Thacore ◽  
...  
1980 ◽  
Vol 238 (5) ◽  
pp. G424-G428
Author(s):  
H. Schiffl ◽  
U. Binswanger

Calcium ATPase, an enzyme involved in intestinal calcium transport, was measured in homogenates of duodenal mucosal scrapings of normal and uremic rats. The effects of calcium deprivation and treatment with 1 alpha,25-dihydroxycholecalciferol [1,25-(OH)2D3] were investigated as well. Uremia decreased the enzyme activity and impaired the rise after calcium deprivation as observed in intact rats. The 1,25-(OH)2D3 treatment increased the enzyme activity in uremic animals and resulted in an identical response to calcium deprivation as observed in intact rats; parathyroidectomy abolished this effect. A striking correlation between everted duodenal gut sac calcium transport and calcium ATPase activity could be demonstrated for all groups of rats studied. It is concluded that the calcium ATPase activity is linked to the production of 1,25-(OH)2D3 as well as to an additional factor, probably parathyroid hormone. The close relationship between enzyme activity and in vitro calcium transport, even during constant physiological supplementation with 1,25-(OH)2D3, suggests an autonomous role of the calcium ATPase activity for mediation of calcium transport in the duodenum in addition to the well-known mechanisms related to vitamin D and its metabolites.


Blood ◽  
1985 ◽  
Vol 66 (2) ◽  
pp. 294-297 ◽  
Author(s):  
A De Flora ◽  
U Benatti ◽  
L Guida ◽  
G Forteleoni ◽  
T Meloni

Abstract The biochemical events that take place during acute hemolysis of G6PD- deficient subjects in favism are far from being elucidated. Evidence is here reported for a constantly and heavily disordered calcium homeostasis in the erythrocytes from seven favic patients. The abnormality, ie, a significantly impaired calcium ATPase activity and a parallel marked increase of intracellular calcium levels, was characteristic of the acute hemolytic crisis although unrelated to the attendant reticulocytosis. Concomitantly, a remarkable decrease of intracellular potassium was also observed. The mean +/- SD Ca2+-ATPase activity in the favic patients was 20.8 +/- 7.8 mumol Pi/g Hb/h compared with 37.2 +/- 8.5 in the matched controls represented by 12 healthy G6PD-deficient subjects (P less than .001). The mean +/- SD intraerythrocytic calcium content was 288 +/- 158 mumol/L of erythrocytes in the favic patients as compared with 22.0 +/- 8.2 in the G6PD-deficient controls (P less than .001). The intraerythrocytic potassium content was 76.6 +/- 19.3 mmol/L of erythrocytes in the favic patients and 106.6 +/- 8.2 in the G6PD-deficient controls (P less than .001). In vitro incubation of normal and G6PD-deficient erythrocytes with divicine, a pyrimidine aglycone present in fava beans and strongly implicated in the pathogenesis of favism, reproduces most of these events, including drop of calcium ATPase, increased intracellular calcium, and leakage of erythrocyte potassium.


1979 ◽  
Vol 237 (3) ◽  
pp. C131-C136 ◽  
Author(s):  
R. K. Entrikin ◽  
S. H. Bryant

We describe myotonic electromyographic activity in muscles of genetically dystrophic chickens and show that this activity is antagonized in vivo by doses of phenytoin (DPH) that improve righting ability. To test the possibility that the in vivo effects of DPH can be accounted for by a direct action on skeletal muscle we studied posterior latissimus dorsi fibers in vitro at 23 degrees C with intracellular microelectrodes. Compared to normal fibers, fibers from untreated dystrophic chicks had larger diameters, increased membrane capacitance, longer latencies at rheobase, and a greater tendency to fire repetitively in response to direct stimulation. DPH (10 or 50 micrograms/ml in the bath solution) decreased latencies at rheobase and repetitive firing in fibers from untreated chicks. In DPH-free solution fibers from dystrophic chicks treated chronically with DPH were still abnormal with respect to latencies at rheobase and ease of repetitive firing. The data support the hypothesis that abnormalities of membrane electrical properties are major features of dystrophic chicken muscles and furthermore, show that DPH suppresses, but does not abolish, these abnormalities.


In Vitro ◽  
1983 ◽  
Vol 19 (9) ◽  
pp. 723-729 ◽  
Author(s):  
D. D. Johnson ◽  
R. Wilcox ◽  
B. Wenger

Blood ◽  
1985 ◽  
Vol 66 (2) ◽  
pp. 294-297
Author(s):  
A De Flora ◽  
U Benatti ◽  
L Guida ◽  
G Forteleoni ◽  
T Meloni

The biochemical events that take place during acute hemolysis of G6PD- deficient subjects in favism are far from being elucidated. Evidence is here reported for a constantly and heavily disordered calcium homeostasis in the erythrocytes from seven favic patients. The abnormality, ie, a significantly impaired calcium ATPase activity and a parallel marked increase of intracellular calcium levels, was characteristic of the acute hemolytic crisis although unrelated to the attendant reticulocytosis. Concomitantly, a remarkable decrease of intracellular potassium was also observed. The mean +/- SD Ca2+-ATPase activity in the favic patients was 20.8 +/- 7.8 mumol Pi/g Hb/h compared with 37.2 +/- 8.5 in the matched controls represented by 12 healthy G6PD-deficient subjects (P less than .001). The mean +/- SD intraerythrocytic calcium content was 288 +/- 158 mumol/L of erythrocytes in the favic patients as compared with 22.0 +/- 8.2 in the G6PD-deficient controls (P less than .001). The intraerythrocytic potassium content was 76.6 +/- 19.3 mmol/L of erythrocytes in the favic patients and 106.6 +/- 8.2 in the G6PD-deficient controls (P less than .001). In vitro incubation of normal and G6PD-deficient erythrocytes with divicine, a pyrimidine aglycone present in fava beans and strongly implicated in the pathogenesis of favism, reproduces most of these events, including drop of calcium ATPase, increased intracellular calcium, and leakage of erythrocyte potassium.


1929 ◽  
Vol 50 (3) ◽  
pp. 315-326 ◽  
Author(s):  
F. Duran-Reynals ◽  
James B. Murphy

Ground muscle from susceptible chickens fixes in vitro in a proportion of instances the agent of the filterable Chicken Tumor I, and in a lesser degree inactivates it, whereas the muscle from resistant animals such as rabbit and pigeon, is without effect. It is shown that the power of fixation of the chicken muscle is far greater than its inactivating properties. Brain and liver from chicken, rabbit and pigeon seem devoid of any action on the agent. The desiccated chicken muscle tissue shares the properties of the fresh organ; and the process of desiccation does not release the agent from the inactive or slightly active mixture of fresh muscle and filtrate.


2006 ◽  
Vol 17 (7) ◽  
pp. 3281-3290 ◽  
Author(s):  
Jing Xiao ◽  
Leslie S. Kim ◽  
Todd R. Graham

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.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Luciane Angela Nottar Nesello ◽  
Maria Luisa Maes Lima Beleza ◽  
Marihá Mariot ◽  
Luísa Nathália Bolda Mariano ◽  
Priscila de Souza ◽  
...  

This study evaluated the gastroprotective value of the methanol extracts from fruits of Morus nigra L. (black mulberry (MEMN)) and Rubus niveus Thunb (raspberry (MERN)). The total phenolic compounds and flavonoids were measured, as well as the in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenger activity. The gastroprotective effects of the extracts against 60% ethanol/0.3 M HCl were evaluated in mice. After that, the lipid hydroperoxides and reduced glutathione levels at ulcerated tissue were determined. The effects of extracts on H+/K+-ATPase activity were also verified. The extracts exhibited high contents of polyphenols; however, MERN presented 1.5-fold higher levels. The presence of flavonoids also was confirmed. In addition, MEMN (IC50 = 13.74 μg/mL) and MERN (IC50 = 14.97 μg/mL) scavenged DPPH radical. The MEMN reduced the ulcer area only at 300 mg/kg (p.o.) by 64.06%. Interestingly, MERN decreased the ulcer area in a superior potency (ED50 = 20.88 mg/kg), reducing the ulcer area by 81.86% at 300 mg/kg, and increased the gastric mucin levels. The antioxidant effects of extracts were evidenced by reduced lipoperoxides and increased reduction of glutathione amount in the gastric mucosa. However, MEMN or MERN did not change the H+/K+-ATPase activity. These results confirm that M. nigra and R. niveus are berries with a gastroprotective value by strengthening of gastric protective factors.


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