The sequence of the 5.8 S ribosomal RNA of the crustacean Artemia salina. With a proposal for a general secondary structure model for 5.8 S ribosomal RNA.

We report the primary structure of 5.8 S rRNA from the crustacean Artemia salina. The preparation shows length heterogeneity at the 5'-terminus, but consists of uninterrupted RNA chains, in contrast to some insect 5.8 S rRNAs, which consist of two chains of unequal length separated in the gene by a short spacer. The sequence was aligned with those of 11 other 5.8 S rRNAs and a general secondary structure model derived. It has four helical regions in common with the model of Nazar et al. (J. Biol. Chem. 250, 8591-8597 (1975)), but for a fifth helix a different base pairing scheme was found preferable, and the terminal sequences are presumed to bind to 28 S rRNA instead of binding to each other. In the case of yeast, where both the 5.8 S and 26 S rRNA sequences are known, the existence of five helices in 5.8 S rRNA is shown to be compatible with a 5.8 S - 26 S rRNA interaction model.     

Independent control of sexual and scent marking behaviors of male gerbils by cells in or near the medial preoptic area

This research studied the role of the medial preoptic area and adjacent cell populations in androgen control of scent marking and sexual behavior in male gerbils (Meriones unguiculatus). Experiment 1 replicated previous research showing that implants of testosterone propionate in or near the medial preoptic area reinstate marking behavior in castrates. Implant sites near the diagonal band of Broca or in the posterior part of the medial preoptic area, near the anterior hypothalamus, are more effective than other sites. Experiment 2 showed that medial preoptic area lesions permanently impair sexual behavior despite testosterone stimulation. Experiments 2–4 showed that lesions in or near the medial preoptic area can also disrupt scent marking; however, this behavior gradually recovered in many lesioned males, especially if they received testosterone. The data suggest that both scent marking and sexual behavior are controlled by androgens acting on cells in or near the medial preoptic area, but the cell populations involved in these two behaviors are probably not the same.     

Amino acid sequence determination of the ADP,ATP carrier from beef heart mitochondria. The sequence of the C-terminal acidolytic fragment

The primary structure of the C-terminal region (94 residues) of the ADP,ATP carrier of beef heart mitochondria is described. CNBr cleavage results in a large peptide (CB1) with Mr 22 000 and several small peptides (CB2 to CB8). Peptide separation was achieved by gel chromatography with 80% formic acid or with an ethanol/formic acid mixture. The amino acid sequence of the small CNBr peptides was determined by solid-phase techniques. Hydrolysis in formic acid cleaves the carrier protein into an Mr 23 000 fragment (A1) with the blocked N-terminus and an Mr 10 000 fragment (A2) starting with proline. The alignment of two CNBr fragments was possible by degradation of A2 by solid-phase methods for 34 steps. The remaining CNBr fragments were arranged by sequencing the tryptic peptides of citraconylated A2.     

Amino acid sequence of the N-terminal non-collagenous segment of dermatosparactic sheep procollagen type I.

The non-collagenous N-terminal segment of type I procollagen from dermatosparactic sheep skin was isolated in the form of the peptide Col 1 from a collagenase digest of the protein. The peptide has a blocked N-terminus, which was identified as pyrrolid-2-one-5-carboxylic acid. Appropriate overlapping fragments were prepared from reduced and alkylated peptide Col 1 by cleavage with trypsin at lysine, arginine and S-aminoethyl-cysteine residues and by cleavage with staphylococcal proteinase at glutamate residues. Amino acid sequence analysis of these fragments by Edman degradation and mass spectrometry established the whole sequence of peptide Col 1 except for a peptide junction (7--8) and a single Asx residue (44), and demonstrated that peptide Col 1 consists of 98 amino acid residues. The N-terminal portion of peptide Col 1 (86 residues) shows an irregular distribution of glycine, whereas the C-terminal portion (12 residues) possesses the triplet structure Gly-Xy and is apparently derived from the precursor-specific collagenous domain of procollagen. The central region of the peptide contains ten cysteine residues located between positions 18 and 73 and shows alternating polar and hydrophobic sequence elements. The regions adjacent to the cysteine-rich portion have a hydrophilic nature and are abundant in glutamic acid. The data are consistent with previous physicochemical and immunological evidence that distinct regions at the N- and C-termini of the non-collagenous domain possess a less rigid conformation than does the central portion of the molecule.     

Cellular aging studied by the reconstruction of replicating cells from nuclei and cytoplasms isolated from normal human diploid cells

Cytochalasin B (CB) was used to enucleate cells (cytoplasts) and to obtain karyoplasts (nuclei) from the human diploid fetal lung fibroblast strain WI-38. Fusion of cytoplasts and nuclei from young and old cells was accomplished with the aid of inactivated Sendai virus. Viable nuclei may be obtained from the karyoplast pellet after passage through a layer of bovine albumin which retains any contamination cytoplasts. The majority of successful fusions forming “whole cells” occurred when cytoplast from “old” cultures (PDL 40–51) and karyoplasts from “young” cultures were used (PDL 12–22), but almost always resulted in limited division of the viable reconstructed cells. When successful fusion occurred between “young” cytoplasts and “young” karyoplasts the number of cell divisions obtained was comparable to control cells kept under similar conditions.     

The morphology of the Limulus visual system

An ocellus of the horseshoe crab, Limulus polyphemus, has been serially sectioned for light and electron microscopy, its sensory cells have been indexed, and the interconnections of a third of these traced. The ocellus contains 155 retinula cells and 26 arhabdomeric cells, which are secondary sensory neurons. Of these, 55 retinula cells constitute 7 quasi-ommatidial assemblages, each innervated by at least one and a total of 9 arhabdomeric cells. When known electrotonic coupling patterns are compared with gap-junctional connections, retinula cells sensitive to visible or ultraviolet light can be tentatively identified. Retinula cell axons contribute collaterals to a synaptic plexus, in which the arhabdomeric cells apparently do not participate.     

Lumi-mestranol and epi-lumi-mestranol.

Treatment of lumi-estrone 3-methyl ether (I) with acetylene gave the C-17-epimeric compounds lumi-mestranol (3-methoxy-17 alpha-ethynyl-13 alpha-estra-1,3,5(10)-trien-17 beta-ol, III ) and epi-lumi-mestranol (3-methoxy-17 beta-ethynyl-13 alpha-estra-1,3,5(10)-trien-17 alpha-ol, IV). The structures of the two isomers were assigned on the basis of their molecular rotations and shift-reagent experiments in the NMR. The irradiation of estrone 3-methyl ether (II) to provide compound I was investigated in two solvent systems. Minor products of these reactions were the seco-steroids VII, VIII and X.     

A comparison of the nitrogen metabolic networks of Kluyveromyces marxianus and Saccharomyces cerevisiae

In grape must, nitrogen is available as a complex mixture of various compounds (ammonium and amino acids). Wine yeasts assimilate these multiple sources in order to suitably fulfil their anabolic requirements during alcoholic fermentation. Nevertheless, the order of uptake and the intracellular fate of these sources are likely to differ between strains and species. Using a two-pronged strategy of isotopic filiation and RNA sequencing, the metabolic network of nitrogen utilization and its regulation in Kluyveromyces marxianus were described, in comparison with those of Saccharomyces cerevisiae. The data highlighted differences in the assimilation of ammonium and arginine between the two species. The data also revealed that the metabolic fate of certain nitrogen sources differed, thereby resulting in the production of various amounts of key wine aroma compounds. These observations were corroborated by the gene expression analysis.     

Luminometric measurement of population activity of genetically modified Pseudomonas fluorescens in the soil

Genetically modified cells of Pseudomonas fluorescens, chromosomally marked with genes for bioluminescence, were inoculated into sterile soil microcosms. During incubation for 90 days, viable cell concentration did not change significantly but light output, measured by luminometry, decreased, indicating reduced metabolic activity due to lack of substrates. Amendment with nutrients resulted in parallel increases in both luminescence and dehydrogenase activity. Luminometry therefore enables rapid monitoring of the activity of populations of luminescence-marked microbial inocula in the soil, with greater sensitivity and selectivity than traditional techniques.