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.     

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     

AIDS-associated renal tuberculosis

In order to study the prevalence and the clinical features of renal tuberculosis associated with AIDS, we studied the renal tissue of the necropsies made in 46 AIDS patients under light microscopy. We found renal tuberculous granuloma in 11 (23%) patients (in 3 without previous diagnosis of renal or extrarenal tuberculosis) and only 4 of them presented moderate hematuria or pyuria sterile. As subclinical renal tuberculosis was frequent in this group of AIDS patients, the urine culture for Mycobacterium tuberculosis may be useful for diagnosing tuberculosis in AIDS patients.