Gastrocnemius Muscle Lipids in Relation to Diet in Two Mouse Mutants, 129Re-dy and A2G-adr, with Abnormal Muscle Function

The lipids of gastrocnemius muscle from normal and dystrophic (dy) mice of the Bar Harbor, 129Re strain were studied. Animals were fed diets containing either 3.1% or 1.1% of total calories as linoleic acid. Lipid analyses were also done on muscle from a new mouse mutant, A2G-adr, which has abnormal muscle function, characterised by an arrested development of the righting response. These animals were fed the "high" linoleic acid diet only. Total lipid, triacylglycerol, and cholesterol were elevated in the 129Re-dy irrespective of the diet, whereas A2G-adr possessed significantly higher levels of cholesterol. Total phosphorus (micrograms P/g muscle) and cholesterol/phospholipid ratios were elevated in the dy strains only. Cardiolipin was raised in the dy ("low" linoleic diet) and adr muscle, whereas phosphatidylcholine was lower in the adr strain only. Linoleic acid esterified to phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine was elevated whereas arachidonic acid in phosphatidylserine was decreased in both mutants. Docosahexanoic acid (22:6) in all three dy phospholipids was decreased, independent of dietary treatment. The adr strain possessed normal levels of this fatty acid. The results specifically point to an abnormality in long-chain polyunsaturated fatty acid metabolism in gastrocnemius muscle in the 129Re-dy mutant; in the adr mutant they could reflect an abnormal increase in the number of muscle mitochondria.     

Postnatal lung function and protein permeability after fetal or maternal corticosteroids in preterm lambs

Rebello, Celso M., Machiko Ikegami, M. Gore Ervin, Daniel H. Polk, and Alan H. Jobe. Postnatal lung function and protein permeability after fetal or maternal corticosteroids in preterm lambs.J. Appl. Physiol. 83(1): 213-218, 1997.We evaluated postnatal lung function andintravascular albumin loss to tissues of 123-days-gestation pretermsurfactant-treated and ventilated lambs 15 h after direct fetal(n = 8) or maternal(n = 9) betamethasone treatment orsaline placebo (n = 9). Thebetamethasone-treated groups had similar increases in dynamiccompliances, ventilatory efficiency indexes, and lung volumes relativeto controls (P < 0.05). The lossesof ¹²⁵I-labeled albumin fromblood, a marker of intravascular integrity, and the recoveries of¹²⁵I-albumin in muscle and brainwere similar for control and betamethasone-exposed lambs.Betamethasone-treated lambs had lower recoveries of¹²⁵I-albumin in lung tissues andin alveolar washes than did controls (P < 0.01). Although blood pressureswere higher for the treated groups (P < 0.05), all groups had similar blood volumes, cardiac outputs, andorgan blood flows. Maternal or fetal treatment with betamethasone 15 hbefore preterm delivery equivalently improved postnatal lung function,reduced albumin recoveries in lungs, and increased blood pressures.However, prenatal betamethasone had no effects on the systemicintravascular losses of albumin or did not change blood volumes.

     

Purification of interferon from mouse Ehrlich ascites tumor cells

Interferon production was induced in mouse Ehrlich ascites tumor cells by infection with Newcastle disease virus. The interferon produced was purified by precipitation with ammonium sulfate, chromatography on carboxymethyl-Sephadex, treatment with blue dextran and polyethylene glycol, gel filtration on Bio-Gel P-60 and Bio-Gel P-200, chromatography on phosphocellulose, isoelectric focusing, and chromatography on octyl-Sepharose. The specific activity of the product was 1.6 x 10(9) NIH mouse interferon reference standard units/mg of protein. Electrophoresis in polyacrylamide gels in the presence of sodium dodecyl sulfate indicated that the apparent molecular weight of the interferon-active material ranged from 25,000 to 35,000. As revealed by staining the gels with Coomassie brilliant blue, the interferon activity co-migrated with the major, broad protein band. Minor, stainable bands of proteins were free of interferon activity and their apparent molecular weight was smaller than 12,000.     

Interferon Treatment of Ehrlich Ascites Tumor Cells: Effects on Exogenous mRNA Translation and tRNA Inactivation in the Cell Extract

We reported earlier that in cell extracts that were prepared from interferon-treated Ehrlich ascites tumor cells and preincubated and passed through Sephadex G-25 (S30_INT), the translation of exogenous mRNA (viral and host) was impaired and the impairment could be overcome to a large extent by adding a crude tRNA preparation from Ehrlich ascites tumor cells but not from Escherichia coli. We find now that the rate of inactivation of some tRNA's (especially those specific for leucine, lysine, and serine) but not those of many others is faster in S30_INT than in corresponding extracts from control cells. This increased rate of tRNA inactivation may perhaps account for the need for added RNA to overcome at least partially the impairment of translation in S30_INT. The relationship of the increased rate of tRNA inactivation to the antiviral effect of interferon is unclear. So far no significant difference has been detected in the amount of tRNA needed to overcome the impairment of encephalomyocarditis virus RNA translation in S30_INT between tRNA from interferon-treated cells and tRNA from control cells. Furthermore, no difference was found in the rate of inactivation in S30_INT between leucine-specific tRNA's from interferon-treated and from control cells. tRNA's specific for leucine and lysine were not inactivated (unless very slowly) during incubation under our conditions in an extract from interferon-treated (or from control) cells unless the extract had been passed through Sephadex G-25 or dialyzed. The translation of exogenous mRNA was, however, impaired in an extract from interferon-treated cells that had not been passed through Sephadex G-25. This impairment was apparently not overcome by added tRNA.     

Characterization and expression analysis of P5CS (Δ1-pyrroline-5-carboxylate synthase) gene in two distinct populations of the Atlantic Forest native species Eugenia uniflora L.

Molecular Biology Reports - Eugenia uniflora is an Atlantic Forest native species, occurring in contrasting edaphoclimatic environments. The identification of genes involved in response to abiotic...