The effect of various treatments in vitro and in vivo on the binding of 125I-labeled anti-rat serum albumin Fab'' to rat tissue polyribosomes

With 125I-labeled Fab' specific for rat liver serine dehydratase it has been possible to localize polyribosomes synthesizing the enzyme under several different environmental conditions. Evidence is presented to show that, following the administration of amino acids in vivo, the relative synthetic capabilities of free and membrane-bound polyribosomes synthesizing serine dehydratase vary with time. Early during the period of induction of the enzyme by administration of amino acids or by feeding a high protein diet the majority of the newly synthesized enzyme is derived from membrane-bound polyribosomes. Later in the induction process an increasing proportion of the enzyme is synthesized by the free polyribosomes. Subcellular localization studies clearly show that serine dehydratase is synthesized by both subclasses of hepatic membrane-bound polyribosomes, the loose and tight membrane-bound polyribosomes, as well as by the free polyribosomes. It was found that the membrane-bound polyribosomes are the preferential sites of synthesis of the majority of serine dehydratase molecules in the Morris hepatomas 5123C and 7800. It is concluded that the synthesis of the enzyme, serine dehydratase, in rat liver is not discretely compartmentalized in either class of free or membrane-bound polyribosomes. Rather, the relative proportions of the serine dehydratase synthesizing polyribosomes within these two classes of polyribosomes can vary depending on the metabolic and physiologic state of the liver cell.     

Racial difference in incidence of ABO hemolytic disease

In this review of 7,464 consecutive infants born at North Carolina Memorial Hospital, hemolytic disease from ABO incompatibility was found to be two to three times as common in black infants as in white infants. The statistical significance of the difference remained high as more restrictive criteria for ABO hemolytic disease were applied. ABO disease, serious enough to cause an indirect serum bilirubin of 15 mg/100ml or higher, had an incidence in black newborns as great as the incidence of Rh hemolytic disease in whites. In contrast, the general prevalence and severity of hyperbilirubinemia was not found to be higher in black newborns than in white infants. The difference cannot be attributed to differences in the prevalence of ABO blood groups between the two races. Policies of early discharge of newborns could be affected by the finding that ABO erythroblastosis is two to three times as common in black infants as in white infants.     

A deoxyribonucleic acid-replication intermediate in the growing mosquito

The arrangement of 18-S rRNA and 28-S rRNA within their 40-S common precursor molecule (pre-rRNA) of Xenopus laevis was investigated by electron microscopic analysis of secondary structure of nascent pre-rRNA chains of oocytes, and by 5'-end analysis of 18-S rRNA and 28-S rRNA hybridized to the EcoRI fragment of rDNA cloned as plasmid pCD42. Secondary structure mapping of phenol-extracted RNA from nucleolar cores revealed complete pre-rRNA chains or molecules at various stages of processing and pre-rRNA molecules apparently lacking one end. In this latter group, which was regarded as representing nascent chains, more than 90% of the molecules had no 28-S rRNA REGION. This shows that the 28-S rRNA sequence is transcribed after the 18-S rRNA region and hence must be located nearer to the 3' end of the pre-rRNA molecule. For 5' end-group determination [3H]uridine-labelled 18-S rRNA and 28-S rRNA were hybridized, as fragments of about 200 nucleotides, to the plasmid pCD42 containing coding sequences for four-fifths of the 18-S rRNA sequence, the external transcribed spacer, the non-transcribed spacer and a tenth of the 28-S rRNA sequence. The RNA was recovered from the hybrids and analyzed for uridine 3',5'-bisphosphate (pUp) after alkaline hydrolysis. The pUp content of the hybridized 18-S rRNA fragments was 20-fold higher than in those of 28-S rRNA, THUS DEMONSTRATING THAT THE 5' END OF THE 18-S rRNA is located next to the external spacer region. From these results it is concluded that the 18-S rRNA is located close to the 5' end of the 40-S pre-rRNA molecule.     

Effects of dietary molybdenum on the metabolism of copper and molybdenum in young cattle

On separate occasions young cattle were injected intrarumenally with 99Mo or 64Cu or intravenously with 64Cu. The metabolism of the isotopes were compared to evaluate metabolic changes associated with molybdenum-induced copper deficiency. Molybdenum-99 metabolism was the same in both controls and experimental subjects. Marked differences in plasma kinetics were observed following intrarumenal 64Cu injection, with experimental animals displaying earlier plasma appearance and maintaining higher plasma levels than did controls. Similarly, higher plasma levels, more rapid plasma reappearance and greater fecal excretion were observed following intravenous injection of 64Cu in the experimental animals than in controls. A mechanism involving abnormal ceruloplasmin synthesis associated with the molybdenum-copper interaction is proposed.     

Anatomical distribution of heavy metals in the scallop Pecten maximus

This paper studied the anatomical distribution of mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni), arsenic (As), silver (Ag), copper (Cu) and zinc (Zn) in the scallop Pecten maximus and the possible implications in terms of shellfish management. Six organs were analysed: mantle, gills, foot, digestive gland, kidney and gonad. On the basis of their anatomical distribution, two groups of metals were able to be distinguished: the first included Pb, Hg, Ni, Zn and Ag; and the second comprised the four other metals studied. The metals in the first group preferentially accumulated in the kidney (except for Pb), with generally much lower concentrations in the other organs. The metals in the second group accumulated mainly in the digestive gland. As and Cu were included in the second group, but they also had particular inter-organ distribution characteristics. Among the edible organs of the scallop only the adductor muscle contained important proportions of one metal, As (which is very likely accumulated as a non-toxic derivative). A selective evisceration of the metal rich non-edible organs may therefore be considered a reliable measure to be taken with a view to reduce the metal content of scallops used for human consumption. This could be especially relevant for Cd, which is accumulated in high concentrations in the digestive gland.     

The effect of sowing date and growth stage on the essential oil composition of three types of parsley (Petroselinum crispum)

Essential oils obtained by simultaneous distillation–extraction (SDE) from leaves, petioles and roots of three types of parsley (turnip‐rooted, plain leaf and curly leaf type), sown on three different dates, were analysed by GC‐MS (gas chromatography–mass spectrometry) analysis. Parsley plants were found to produce mainly β‐phellandrene, 1,3,8‐p‐menthatriene, α‐,p‐dimethylstyrene, myristicin, β‐myrcene and apiole. In some cases α‐ and β‐pinene were also found, whereas β‐elemene was detected, especially in the curly leaf type. The growth stage, plant tissue and date of sowing, as well as the climate conditions, all had a significant effect on the essential oil composition by altering the ratio of the above substances. Copyright © 2004 Society of Chemical Industry     

Chemometric Analysis for the Detection of Biogenic Amines in Chilean Cabernet Sauvignon Wines: A Comparative Study between Organic and Nonorganic Production

In this work, the presence of biogenic amines (BAs) was correlated with the type of wine grape culture (traditional or organic) and their concentration in the different stages of winemaking (must, alcoholic fermentation [AF] and malolactic fermentation [MLF]). The formation of BA occurred mainly during MLF in which the percentages for putrescine, cadaverine, phenylethylamine, histamine, and tyramine were 100%, 70%, 13%, 61%, and 44% for the wines produced with traditional grapes and 100%, 94%, 25%, 88%, and 13% for the wines produced with organic grapes, respectively. In general, these latter wines exhibited a lower concentration of total amines. The principal component analysis and partial least-square discriminate analysis indicated that the generation of BA has a certain behavioral pattern in the wines analyzed, which is associated with the different stages of wine production and with the type of culture (traditional or organic) used in the wine grapes. Practical Application: Chemometrics tools can be useful as a method of characterization and classification in a global overview of the process variables involved in the development of toxic chemicals in foods, such as the production of BA in wine.