The effects of aflatoxin B1 on protein synthesis by cucumber cotyledon discs

1970 ◽  
Vol 48 (3) ◽  
pp. 485-491 ◽  
Author(s):  
B. Truelove ◽  
D. E. Davis ◽  
Olivia C. Thompson
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Time Course ◽  
Actinomycin D ◽  
Amino Acid Uptake ◽  
Plant Tissues ◽  
Acid Uptake ◽  
Cucumber Cotyledon ◽  
Low Concentrations ◽  
Aflatoxin Concentration

The effects of aflatoxin on amino acid uptake and incorporation into protein by discs of cucumber cotyledon tissue showed that incubation for relatively short periods with low concentrations of aflatoxin reduced the amount of 14C-leucine absorbed without affecting incorporation into protein; increasing incubation time or increasing aflatoxin concentration inhibited the incorporation of absorbed leucine into protein. The effects of aflatoxin and actinomycin D on leucine absorption and incorporation were compared in a time course study.The data are discussed in relation to the possible mode of action of aflatoxin in plant tissues.

The effects of aflatoxin B1, citrinin, and ochratoxin A on amino acid uptake and incorporation by cucumber

1972 ◽  
Vol 50 (12) ◽  
pp. 2659-2664 ◽  
Author(s):  
Audrey G. White ◽  
Bryan Truelove
Keyword(s):  
Amino Acid ◽  
Ochratoxin A ◽  
Time Course ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Cucumber Cotyledon ◽  
Leucine Uptake ◽  
Pretreatment Time ◽  
Aflatoxin B ◽  
Subsequent Incorporation

Both aflatoxin B1 and citrinin, in light and darkness, inhibited leucine uptake and its incorporation into protein by cucumber cotyledon disks. Aflatoxin was more inhibitory in the light and both toxins showed increased inhibition with increasing concentration. At a concentration of 50 μg/ml, citrinin was more inhibitory to amino acid absorption than aflatoxin. Time-course studies showed that a pretreatment time of at least 2 h was necessary with aflatoxin to affect the subsequent incorporation of leucine; citrinin, on the other hand, was inhibitory when it was supplied together with the 14C-leucine. In darkness, ochratoxin A at 10, 50, and 100 μg/ml enhanced leucine uptake but did not affect its incorporation into protein.

scholarly journals Action of growth hormone in vitro on the net uptake and incorporation into protein of amino acids in muscle from intact rabbits given protein-deficient diets

1976 ◽  
Vol 35 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Turner ◽  
P. J. Reeds ◽  
K. A. Munday
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Protein Synthesis ◽  
Amino Acid ◽  
De Novo ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Amino Acid Incorporation ◽  
Acid Incorporation

1. Net amino acid uptake, and incorporation into protein have been measured in vitro in the presence and absence of porcine growth hormone (GH) in muscle from intact rabbits fed for 5 d on low-protein (LP), protein-free (PF) or control diets.2. In muscle from control and LP animals GH had no effect on the net amino acid uptake but stimulated amino acid incorporation into protein, although this response was less in LP animals than in control animals.3. In muscle from PF animals, GH stimulated both amino acid incorporation into protein and the net amino acid uptake, a type of response which also occurs in hypophysectomized animals. The magnitude of the effect of GH on the incorporation of amino acids into protein was reduced in muscle from PF animals.4. The effect of GH on the net amino acid uptake in PF animals was completely blocked by cycloheximide; the uptake effect of GH in these animals was dependent therefore on de novo protein synthesis.5. It is proposed that in the adult the role of growth hormone in protein metabolism is to sustain cellular protein synthesis when there is a decrease in the level of substrate amino acids, similar to that which occurs during a short-term fast or when the dietary protein intake is inadequate.

scholarly journals Action of insulin and growth hormone on protein synthesis in muscle from non-hypophysectomized rabbits

1971 ◽  
Vol 125 (2) ◽  
pp. 515-520 ◽  
Author(s):  
P. J. Reeds ◽  
K. A. Munday ◽  
M. R. Turner
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Incubation Medium ◽  
Amino Acid Uptake ◽  
Diaphragm Muscle ◽  
Acid Uptake

The separate effects of insulin and growth hormone on the uptake and incorporation of five amino acids into diaphragm muscle from non-hypophysectomized rabbits has been examined. Both growth hormone and insulin, when present in the medium separately, stimulated the incorporation into protein of the amino acids, leucine, arginine, valine, lysine and histidine. Insulin also stimulated amino acid uptake, but growth hormone did not. When insulin and growth hormone were present in the incubation medium together, the uptake and incorporation of valine, the only amino acid studied under these conditions, tended to be greater than the sum of the separate effects of the two hormones.

Protein and energy metabolism in the pre-implantation cattle embryo

2001 ◽  
Vol 26 (2) ◽  
pp. 443-446 ◽  
Author(s):  
D.G. Morris ◽  
P. Humpherson ◽  
H.J. Leese ◽  
J.M. Sreenan
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Energy Metabolism ◽  
Metabolic Rate ◽  
Protein Content ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Glucose Utilisation ◽  
Embryonic Loss

AbstractThere is no information on the metabolism of the cattle embryo during the period from day 8 to 16 a period of greatest embryonic loss. In this study the rate of protein synthesis and phosphorylation was measured in 13 to 15 day old cattle embryos. The rate of glucose utilisation and amino acid uptake/efflux by day 14 to 16 embryos was also measured. Protein synthesis and phosphorylation activity when expressed per unit of protein decreased with increasing embryo size and age. Similarly the rate of glucose utilisation was greatest for the earlier day 14 embryos. Embryos differed in their requirement for different amino acids. The pattern of uptake/efflux was similar to that of the earlier day 7 embryo. This study suggests that the metabolic rate of cattle embryos expressed per unit of protein content tends to decrease with increasing age and size from the initial burst of activity at day 13 around the time that expansion of the embryo begins.

Follicle-stimulating hormone administration affects amino acid metabolism in mammalian oocytes†

2019 ◽  
Vol 101 (4) ◽  
pp. 719-732 ◽  
Author(s):  
Anna Tetkova ◽  
Andrej Susor ◽  
Michal Kubelka ◽  
Lucie Nemcova ◽  
Denisa Jansova ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Follicle Stimulating Hormone ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Fsh Receptor ◽  
Cytoplasmic Maturation ◽  
Vitro Effect ◽  
Stimulating Hormone

Abstract Culture media used in assisted reproduction are commonly supplemented with gonadotropin hormones to support the nuclear and cytoplasmic maturation of in vitro matured oocytes. However, the effect of gonadotropins on protein synthesis in oocytes is yet to be fully understood. As published data have previously documented a positive in vitro effect of follicle-stimulating hormone (FSH) on cytoplasmic maturation, we exposed mouse denuded oocytes to FSH in order to evaluate the changes in global protein synthesis. We found that dose-dependent administration of FSH resulted in a decrease of methionine incorporation into de novo synthesized proteins in denuded mouse oocytes and oocytes cultured in cumulus-oocyte complexes. Similarly, FSH influenced methionine incorporation in additional mammalian species including human. Furthermore, we showed the expression of FSH-receptor protein in oocytes. We found that major translational regulators were not affected by FSH treatment; however, the amino acid uptake became impaired. We propose that the effect of FSH treatment on amino acid uptake is influenced by FSH receptor with the effect on oocyte metabolism and physiology.

Differential regulation of T-cell growth by IL-2 and IL-15

Blood ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 600-608 ◽  
Author(s):  
Georgina H. Cornish ◽  
Linda V. Sinclair ◽  
Doreen A. Cantrell
Keyword(s):  
T Cells ◽  
Protein Synthesis ◽  
Amino Acid ◽  
T Cell ◽  
Cell Growth ◽  
De Novo ◽  
Cell Mass ◽  
Interleukin 2 ◽  
Amino Acid Uptake ◽  
Acid Uptake

Although interleukin 2 (IL-2) and IL-15 signal through the common gamma chain (γc) and through IL-2 receptor β–chain (CD122) subunits, they direct distinct physiologic and immunotherapeutic responses in T cells. The present study provides some insight into why IL-2 and IL-15 differentially regulate T-cell function by revealing that these cytokines are strikingly distinct in their ability to control protein synthesis and T-cell mass. IL-2 and IL-15 are shown to be equivalent mitogens for antigen-stimulated CD8+ T cells but not for equivalent growth factors. Antigen-primed T cells cannot autonomously maintain amino acid incorporation or de novo protein synthesis without exogenous cytokine stimulation. Both IL-2 and IL-15 induce amino acid uptake and protein synthesis in antigen-activated T cells; however, the IL-2 response is strikingly more potent than the IL-15 response. The differential action of IL-2 and IL-15 on amino acid uptake and protein synthesis is explained by temporal differences in signaling induced by these 2 cytokines. Hence, the present results show that cytokines that are equivalent mitogens can have different potency in terms of regulating protein synthesis and cell growth.

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