Relation of Protein Synthesis to Plasma and Cell Amino Acids in Neonates

Abstract

We hypothesized that more rapidly growing preterm infants would have higher rates of protein synthesis than term infants, and that protein synthesis would be more closely related to intracellular than plasma levels of amino acids. Neutrophils, used as a cell model, were isolated from 1-3 ml blood of 63 infants 27-44 wk postconceptual age. Protein synthesis (3H-leucine incorporation, pmol/h/mg DNA), and 19 amino acids in the leukocytes (nmol/mg DNA) and plasma (nmol/ml) were quantified. Protein synthesis was related inversely to birth weight and gestational age, i.e. the smaller and more preterm the infant the higher the rate of protein synthesis. Multiple regression analysis limited to six steps indicated that some plasma amino acids (Val, Ile, Phe, Asp, Ala, Tau) accounted for a significant (p = 0.03), but relatively small, proportion, 23%, of the variance in protein synthesis. A greater proportion of the variance in protein synthesis was explained by a set of six intracellular amino acids (Leu, Met, Tyr, Gly, Ala, Tau), with R2 = 36%, p = 0.001. Further, multiple regression identified specific combinations of six plasma amino acids which best explained ("predicted") the levels of each intracellular amino acid predictor of protein synthesis (R2 = 0.4-0.5, p less than 0.001-0.0001). Activities of some rate-limiting glycolytic enzymes, pyruvate kinase and phosphofructokinase, were correlated with protein synthesis in the leukocytes (p = 0.036, and 0.002, respectively). Phosphofructokinase, the major regulating enzyme in glycolysis, also was negatively correlated with birth weight and gestational age.(ABSTRACT TRUNCATED AT 250 WORDS)

Maternal probiotics supplementation improves immune and antioxidant function in suckling piglets via modifying gut microbiota

“…Cysteine can be decarboxylated into taurine and Tau. Taurine can effectively improve lipid metabolism in animals by promoting catabolic metabolism of fat, thus reducing TG synthesis and liver fat accumulation (Johnson & Metcoff, 1986). In the present study, maternal probiotics supplementation decreased plasma Ala and Tau levels of piglets while increased Cys and 1‐Mehis levels.…”

Placental circadian lincRNAs and spontaneous preterm birth

“…sPTB has also been linked to placental oxidative stress ( Chang et al, 2013 ; Menon, 2014 ; Polettini et al, 2014 ; Perrone et al, 2016 ; Saroyo et al, 2021 ), cellular senescence ( Cha and Aronoff, 2017 ; Menon et al, 2017 ; Saroyo et al, 2021 ), apoptosis ( Tarquini et al, 2018 ; Kovács et al, 2020 ), autophagy ( Agrawal et al, 2015 ; Cao et al, 2016 ), methylation ( Tilley et al, 2018 ; Mani et al, 2019 ; Schuster et al, 2019 ; Li et al, 2020 ; Wang et al, 2022 ), and energy metabolism ( Elshenawy et al, 2020 ; Lien et al, 2020 ; Lien et al, 2021 ). In addition, there is evidence that protein synthesis is inversely related to birth weight and gestational age ( Johnson and Metcoff, 1986 ). Taken together, our results suggest that the identified five circadian lincRNAs might be involved in placental intertwined pathophysiological processes leading to sPTB.…”

Turnover of Short-Lived Proteins in Chick Leukocytes following Dietary Treatments

“…In one study [41] changes in calcium concentration in vitro increased deg radation rates by threefold. In two other stud ies [8,9], the effect of the physiological status on protein synthesis of leukocytes was shown. In a recent study, protein synthesis measured in vivo (using enriched 2H-phe and mass spec trometry) was increased by 40%, in leuko cytes, 24 h after surgery [42], This finding supports the feasibility of monitoring catabol ic states by leukocyte metabolism.…”

“…Leukocyte metabolism [6,7] as well as their total protein synthesis [8,9], as assayed in vitro, are highly affected by the donor's Here we report the effect of protein intake in young chicks on in vitro leukocyte protein synthesis and degradation and suggest a meth od for measuring the impact of nutritional treatments on the degradation of short-lived proteins in intact animals. The body weight range for group 1 was 66 -7 6 g and for group 2 69-72 g. Blood was withdrawn as described.…”