In vitro Na+, K+-ATPase (EC 3.6.1.3)-dependent respiration and protein synthesis in skeletal muscle of pigs fed at three dietary protein levels

1989 ◽  
Vol 61 (3) ◽  
pp. 453-465 ◽  
Author(s):  
O. Adeola ◽  
L. G. Young ◽  
B. W. Mcbride ◽  
R. O. Ball

1. Eighteen pigs were offered diets containing 130, 170 or 210 g protein/kg with three barrows and three gilts per diet from 20 to 60 kg live weight. Oxygen consumption, Na1, K1-ATPase (EC 3·6·1· 3)-dependent and -independent respiration and protein synthesis were measured in vitro in intercostal and sartorius muscle preparations from these pigs.2. Increasing dietary protein concentration increased (P < 0·01) daily gain and dissectible muscle in carcass.3. O2 consumption and Na+, K+-ATPase-dependent respiration of the intercostal and sartorius muscles increased linearly (P < 0·01) with increase in dietary protein concentration. The requirement for the support of the transport of Na+ and K+ across the cell membrane in these muscles, on average, accounted for 22–25% of the O2 consumption.4. Synthesis rate (mg/g per d) of protein in the sartorius muscle increased (P < 0·05) from 3·05 to 5·07 and increased (P < 0·1) from 2·57 to 4.06 in the intercostal muscle as dietary protein increased from 130 to 210 g/kg diet.5. Regression of Na+, K+-ATPase-dependent respiration against protein synthesis in each of intercostal and sartorius muscles showed a linear relation, an attestation of a close link between productive processes and auxiliary energy expenditure.

2001 ◽  
Vol 101 (6) ◽  
pp. 583-589 ◽  
Author(s):  
Giuseppe CASO ◽  
Peter J. GARLICK ◽  
Marie C. GELATO ◽  
Margaret A. MCNURLAN

HIV infection has been shown to affect lymphocyte function and to reduce lymphocyte responsiveness in vitro to mitogenic stimulation, but little is known about lymphocyte metabolism in vivo and how it is affected during the course of the disease. This study investigated the metabolic activity of lymphocytes in vivo through the progression of HIV-associated disease. Lymphocyte protein synthesis was measured with l-[2H5]phenylalanine (45mg/kg body weight) in healthy volunteers (n = 7), in patients who were HIV-positive (n = 7) but asymptomatic, and in patients with AIDS (n = 8). The rates of lymphocyte protein synthesis [expressed as a percentage of lymphocyte protein, i.e. fractional synthesis rate (FSR)] were not altered in HIV-positive patients compared with healthy controls (7.9±1.28% and 9.1±0.53%/day respectively), but were significantly elevated in AIDS patients (14.0±1.16%/day; P < 0.05). The serum concentration of the cytokine tumour necrosis factor-α (TNF-α) increased with the progression of the disease, and TNF-α levels were significantly higher in AIDS patients (6.81±0.88ng/l) than in healthy controls (3.09±0.27ng/l; P < 0.05). Lymphocyte protein FSR was positively correlated with serum TNF-α concentration (r = 0.55, P = 0.009) and negatively correlated with CD4+ lymphocyte count (r =-0.70, P = 0.004). The elevation of lymphocyte protein synthesis in AIDS patients suggests a higher rate of turnover of lymphocytes. This may be associated with a generalized activation of the immune system, which is also reflected by the elevated serum TNF-α concentration in the late stages of HIV-associated disease.


1993 ◽  
Vol 264 (2) ◽  
pp. H573-H582
Author(s):  
W. A. Clark ◽  
S. J. Rudnick ◽  
D. G. Simpson ◽  
J. J. LaPres ◽  
R. S. Decker

Previous studies have shown that the rates of protein synthesis observed in embryonic and neonatal heart cells in culture are as much as nine times greater than the rates of synthesis observed in the intact adult heart either in situ or in isolated perfusion studies. This study addressed whether adult cardiomyocytes in long-term culture maintain the protein synthetic capacity of the adult myocardium or, rather, whether the protein synthetic capacity expands or falls as adult cardiac myocytes progress in culture. Protein synthesis was evaluated in isolated adult feline cardiomyocytes maintained in serum and insulin-supplemented medium for up to 53 days in vitro. With the use of both pulse- and saturation-labeling techniques it was determined that the rate of protein synthesis in adult cardiomyocytes was maintained at a level very close to that observed in the intact heart for over 1 mo in culture. Saturation-labeling studies indicate a fractional rate of protein synthesis at 6.1%/day and an absolute synthesis rate of 1,300 nmol leucine incorporated.g protein-1.h-1. Pulse-labeling studies revealed an initial increase in protein synthesis rates during adaptation to culture and a further increase after activation of beating and cellular hypertrophy.


1985 ◽  
Vol 40 (1) ◽  
pp. 39-45 ◽  
Author(s):  
J. S. Gonzalez ◽  
J. J. Robinson ◽  
I. McHattie

ABSTRACTThirty-six individually-penned ewes (mean live weight 69 kg), each suckling two lambs, were given one of three diets containing either 128 (low), 155 (medium) or 186 (high) g crude protein (CP) per kg dry matter. All diets contained (g/kg), milled hay, 570; molasses, 95; and a barley/fish meal concentrate, 330. The three protein concentrations were achieved by adjusting the proportions of barley and fish meal in the concentrate. Each diet was given at daily metabolizable energy (ME) intakes of 19, 23 and 27 MJ. Mean daily yields of milk in weeks 3 to 8 of lactation for ewes given the diet with the low concentration of crude protein increased from 2·32 kg at 19 MJ ME to 2·53 kg at 27 MJ. Corresponding values for the medium concentration of CP were 2·49 and 2·67 kg and for the high concentration 2·52 and 3·09 kg (P < 0·05 for differences between ME intakes and differences between dietary protein concentrations). For milk composition, interactions between the concentration of dietary protein and level of ME intake were not statistically significant but the main treatment effects were significant, with the protein concentration in milk increasing from 49·6 g/kg for ewes given the low concentration of dietary protein to 54·1 g/kg for those given the high (P < 0·001). Corresponding values for protein concentration in milk for the lowest and highest energy intake were 51·2 and 53·4 g/kg (P < 0·05). Losses of tissue protein were variable but decreased from 26 g/day for ewes given the low-protein diet to 8 g/day for those given the high. In discussing the responses in milk yield to dietary protein and ME intake attention is drawn to the modifying influence of the energy contributed from body tissue.


1998 ◽  
Vol 38 (2) ◽  
pp. 188-189
Author(s):  
M. A. Arnal ◽  
M. C. Valluy ◽  
P. Capitan ◽  
G. Bayle ◽  
P. Patureau Mirand

1995 ◽  
Vol 15 (1) ◽  
pp. 15-20 ◽  
Author(s):  
M. E. Martin ◽  
A. M. Garcia ◽  
L. Blanco ◽  
E. Herrera ◽  
M. Salinas

To study the effect of diabetes on hepatic protein synthesis and polysomal aggregation in pregnant rats, female rats were treated with streptozotocin prior to conception. Some animals were mated, and studied at day 20 of pregnancy, whereas, others were studied in parallel under non pregnant conditions. The protein synthesis rate measured with an “in vitro” cell-free system was higher in pregnant than in virgin control rats. It decreased with diabetes in both groups, although values remained higher in diabetic pregnant rats than in the virgin animals. The fetuses of diabetic rats had a lower protein synthesis rate than those from controls, although they showed a higher protein synthesis rate than either their respective mothers or virgin rats. Liver RNA concentration was higher in control and diabetic, pregnant rats than in virgin rats, and the effect of diabetes decreasing this parameter was only significant for pregnant rats. Liver RNA concentration in fetuses was lower than in their mothers, and did not differ between control and diabetic animals. The decreased protein synthesis found in diabetic animals was accompanied by disaggregation of heavy polysomes into lighter species, indicating an impairment in peptide-chain initiation.


2020 ◽  
Vol 86 (10) ◽  
Author(s):  
Xuedan Wang ◽  
Glenn R. Gibson ◽  
Manuela Sailer ◽  
Stephan Theis ◽  
Robert A. Rastall

ABSTRACT Dietary protein residue can result in microbial generation of various toxic metabolites in the gut, such as ammonia. A prebiotic is “a substrate that is selectively utilised by host microorganisms conferring a health benefit” (G. R. Gibson, R. Hutkins, M. E. Sanders, S. L. Prescott, et al., Nat Rev Gastroenterol Hepatol 14:491–502, 2017, https://doi.org/10.1038/nrgastro.2017.75). Prebiotics are carbohydrates that may have the potential to reverse the harmful effects of gut bacterial protein fermentation. Three-stage continuous colonic model systems were inoculated with fecal samples from omnivore and vegetarian volunteers. Casein (equivalent to 105 g protein consumption per day) was used within the systems as a protein source. Two different doses of inulin-type fructans (Synergy1) were later added (equivalent to 10 g per day in vivo and 15 g per day) to assess whether this influenced protein fermentation. Bacteria were enumerated by fluorescence in situ hybridization with flow cytometry. Metabolites from bacterial fermentation (short-chain fatty acid [SCFA], ammonia, phenol, indole, and p-cresol) were monitored to further analyze proteolysis and the prebiotic effect. A significantly higher number of bifidobacteria was observed with the addition of inulin together with reduction of Desulfovibrio spp. Furthermore, metabolites from protein fermentation, such as branched-chain fatty acids (BCFA) and ammonia, were significantly lowered with Synergy1. Production of p-cresol varied among donors, as we recognized four high producing models and two low producing models. Prebiotic addition reduced its production only in vegetarian high p-cresol producers. IMPORTANCE Dietary protein levels are generally higher in Western populations than in the world average. We challenged three-stage continuous colonic model systems containing high protein levels and confirmed the production of potentially harmful metabolites from proteolysis, especially replicates of the transverse and distal colon. Fermentations of proteins with a prebiotic supplementation resulted in a change in the human gut microbiota and inhibited the production of some proteolytic metabolites. Moreover, we observed both bacterial and metabolic differences between fecal bacteria from omnivore donors and vegetarian donors. Proteins with prebiotic supplementation showed higher Bacteroides spp. and inhibited Clostridium cluster IX in omnivore models, while in vegetarian modes, Clostridium cluster IX was higher and Bacteroides spp. lower with high protein plus prebiotic supplementation. Synergy1 addition inhibited p-cresol production in vegetarian high p-cresol-producing models while the inhibitory effect was not seen in omnivore models.


2019 ◽  
Vol 40 (5) ◽  
pp. 1061-1076 ◽  
Author(s):  
Junchao Tong ◽  
Belinda Williams ◽  
Pablo M. Rusjan ◽  
Romina Mizrahi ◽  
Jean-Jacques Lacapère ◽  
...  

Positron emission tomography (PET) imaging of the translocator protein (TSPO) is widely used as a biomarker of microglial activation. However, TSPO protein concentration in human brain has not been optimally quantified nor has its regional distribution been compared to TSPO binding. We determined TSPO protein concentration, change with age, and regional distribution by quantitative immunoblotting in autopsied human brain. Brain TSPO protein concentration (>0.1 ng/µg protein) was higher than those reported by in vitro binding assays by at least 2 to 70 fold. TSPO protein distributed widely in both gray and white matter regions, with distribution in major gray matter areas ranked generally similar to that of PET binding in second-generation radiotracer studies. TSPO protein concentration in frontal cortex was high at birth, declined precipitously during the first three months, and increased modestly during adulthood/senescence (10%/decade; vs. 30% for comparison astrocytic marker GFAP). As expected, TSPO protein levels were significantly increased (+114%) in degenerating putamen in multiple system atrophy, providing further circumstantial support for TSPO as a gliosis marker. Overall, findings show some similarities between TSPO protein and PET binding characteristics in the human brain but also suggest that part of the TSPO protein pool might be less available for radioligand binding.


1992 ◽  
Vol 262 (6) ◽  
pp. C1471-C1477 ◽  
Author(s):  
J. A. Chromiak ◽  
H. H. Vandenburgh

Glucocorticoids induce rapid atrophy of fast skeletal myofibers in vivo, and either weight lifting or endurance exercise reduces this atrophy by unknown mechanisms. We examined the effects of the synthetic glucocorticoid dexamethasone (Dex) on protein turnover in tissue-cultured avian fast skeletal myofibers and determined whether repetitive mechanical stretch altered the myofiber response to Dex. In static cultures after 3-5 days, 10(-8) M Dex decreased total protein content 42-74%, total protein synthesis rates 38-56%, mean myofiber diameter 35%, myosin heavy chain (MHC) content 86%, MHC synthesis rate 44%, and fibronectin synthesis rate 29%. Repetitive 10% stretch-relaxations of the cultured myofibers for 60 s every 5 min for 3-4 days prevented 52% of the Dex-induced decrease in protein content, 42% of the decrease in total protein synthesis rate, 77% of the decrease in MHC content, 42% of the decrease in MHC synthesis rate, and 67% of the decrease in fibronectin synthesis rate. This in vitro model system will complement in vivo studies in understanding the mechanism by which mechanical activity and glucocorticoids interact to regulate skeletal muscle growth.


2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii51-iii51
Author(s):  
D Pandey ◽  
F Mohammad ◽  
S Weissmann ◽  
P Hallenborg ◽  
B Blagoev ◽  
...  

Abstract Glioblastoma multiforme (GBM) is one of the most aggressive types of tumors with a poor response to standard treatment and a median 5-year survival of less than 5%. Therefore, there is an urgent need for new treatments. Recently, a large number of genome-wide studies have shown that the epigenetic modifiers are frequently deregulated in cancer. Using a mouse GBM model, we performed in vitro and in vivo shRNA screens to identify epigenetic regulators required for the tumorigenic process in GBM. Among these regulators is a ribosome hydroxylase Mina53 which hydroxylates His-39 of ribosomal protein, RPL27a. We have found that the knock-down (KD) of Mina53 reduces the in vitro proliferation and colony forming ability of mouse glioma initiating cells (mGIC) and this is dependent on the catalytic activity of Mina. Knock-down of Mina resulted into a small but significant reduction in the global protein synthesis rate. A tandem affinity purification experiment to identify proteins associated with Mina revealed that it is associated mainly with ribosomal proteins, including its substrate RPL27a. Global proteomic analyses revealed that final amounts and de novo protein synthesis of many ribosomal proteins were reduced upon Mina depletion. Isolation and identification of different polysome fraction bound mRNAs using high-throughput sequencing found that mRNAs encoding many ribosomal proteins have lower number of ribosomes loaded on them in the Mina depleted samples compared to the control. Taken together, this study has found that Mina53 is required for glioblastoma and it regulates translation through regulation of ribosomal biogenesis


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