Olives and olive oil in cancer prevention

Epidemiologic studies conducted in the latter part of the twentieth century demonstrate fairly conclusively that the people of the Mediterranean basin enjoy a healthy lifestyle with decreased incidence of degenerative diseases. The data show that populations within Europe that consume the so-called 'Mediterranean diet' have lower incidences of major illnesses such as cancer and cardiovascular disease. Studies have suggested that the health-conferring benefits of the Mediterranean diet are due mainly to a high consumption of fibre, fish, fruits and vegetables. More recent research has focused on other important factors such as olives and olive oil. Obviously fibre (especially wholegrain-derived products), fruits and vegetables supply an important source of dietary antioxidants. What is the contribution from olives and olive oil? Apparently the potential is extremely high but epidemiologic studies rarely investigate consumption of these very important products in-depth, perhaps due to a lack of exact information on the types and amounts of antioxidants present. Recent studies have shown that olives and olive oil contain antioxidants in abundance. Olives (especially those that have not been subjected to the Spanish brining process) contain up to 16 g/kg typified by acteosides, hydroxytyrosol, tyrosol and phenyl propionic acids. Olive oil, especially extra virgin, contains smaller amounts of hydroxytyrosol and tyrosol, but also contains secoiridoids and lignans in abundance. Both olives and olive oil contain substantial amounts of other compounds deemed to be anticancer agents (e.g. squalene and terpenoids) as well as the peroxidation-resistant lipid oleic acid. It seems probable that olive and olive oil consumption in southern Europe represents an important contribution to the beneficial effects on health of the Mediterranean diet.

Noninvasive, optical detection of diabetes: model studies with porcine skin

An in vitro study was performed to evaluate noninvasive spectroscopic measurement of advanced glycation endproducts (AGEs) in skin collagen. A porcine dermis preparation was incubated in solutions simulating normal and hyperglycemic conditions. The AGEs kinetics of increase were determined by HPLC and GC/MS assays, and compared to near-infrared (NIR) and ultraviolet/visible fluorescence skin spectra. Multivariate analysis indicated that, although NIR did not discriminate between collagen samples exposed to different glucose concentrations, fluorescence changes were readily detected and correlated strongly with skin concentration of AGEs. These results suggest that measurement of skin AGEs by fluorescence spectroscopy may be useful for detection and diagnosis of type II diabetes.

Moving cemeteries: a framework for facilitating curriculum revision

The process of revising a nursing curriculum can be accompanied by self-oriented faculty behaviors such as inflexibility, indifference, and territoriality. The authors, who served as members of a curriculum revision task force, suggest the need for planned, intentional, and goal-directed approaches when revising an academic program. Lancaster's six components of research by committee are used as a framework to offer insights for enhancing.

The Plasmodium falciparum-CD36 interaction is modified by a single amino acid substitution in CD36

CD36 is an 88-kD glycoprotein involved in the cytoadherence of Plasmodium falciparum-parasitized erythrocytes (PE) to endothelial cells. The molecular mechanisms involved in CD36-dependent cytoadherence were examined by expressing three CD36 homologues (human, murine, and rat) in COS-7 cells and observing their PE-binding characteristics over a pH range of 6.0 to 7.4 and following iodination of these receptors. PE binding to human CD36 was pH dependent, with peak binding at pH 6.8 to 7.0, and binding was unaffected by iodination. In contrast, PE adherence to murine and rat CD36 was insensitive to changes in pH, and iodination significantly reduced binding. We further show that the differences observed in the binding phenotype of human and rodent CD36 can be attributed to a single residue. Site-directed mutagenesis of the histidine at position 242 of human CD36 to tyrosine (found in rodent CD36) conferred the binding phenotype of rodent CD36 onto human CD36. Furthermore, substitution of the tyrosine at position 242 of rat CD36 for histidine conferred the binding phenotype of human CD36 onto rat CD36. These findings suggest that residue 242 is part of, or important to the conformation of, the PE-binding domain of CD36.

Sequence, exon-intron organization, transcription and mutational analysis of prnA, the gene encoding the transcriptional activator of the prn gene cluster in Aspergillus nidulans

The prnA gene codes for a transcriptional activator that mediates proline induction of four other genes involved in proline utilization as a nitrogen and/or carbon source in Aspergillus nidulans. In this paper, we present the genomic and cDNA sequence and the transcript map of prnA. The PrnA protein belongs to the Zn binuclear cluster family of transcriptional activators. The gene shows a striking intron-exon organization, with the putative nuclear localization sequence and the Zn cluster domain in discrete exons. Although the protein sequence presents some interesting similarities with the isofunctional protein of Saccharomyces cerevisiae Put3p, a higher degree of similarity is found with a functionally unrelated protein Thi1 of Schizosaccharomyces pombe. A number of mutations mapping in the prnA gene were sequenced. This comprises a deletion that results in an almost complete loss of the prnA-specific mRNA, a mutation in the putative nuclear localization signal, a proline to leucine mutation in the second loop of the zinc cluster and a cold-sensitive mutation in the so-called 'central region'. Other complete or partial loss of function mutations map in regions of unknown function. We establish that the transcription of the gene is neither self-regulated nor significantly affected by carbon and/or nitrogen metabolite repression.

Correlation of the conformation of a modified ribonuclease octapeptide, homologous to peptide T, with its ability to induce CD4-dependent monocyte chemotaxis

Peptide T, from the human immunodeficiency virus (HIV), whose sequence is Ala-Ser-Thr-Thr-Thr-Asn-Tyr-Thr, has been shown to inhibit attachment of this virus to T cells and neural cells bearing the CD4 receptor. This peptide shares extensive homology with the 19-26 segment of ribonuclease A (RNase A), whose sequence is Ala-Ala-Ser-Ser-Ser-Asn-Tyr-Cys. Based on comparison of the structures of peptides occurring in proteins of known structure that are homologous to peptide T, viz, RNase A and endothiapepsin and on conformational energy calculations, we predicted that peptide T adopts a structure much like that for residues 19-26 in RNase A. A critical feature is a bend involving residues Thr 4-Asn 7 in peptide T corresponding to Ser 22-Tyr 25 in the RNase A peptide. Our proposed structure for peptide T has recently been confirmed by Cotelle et al. (Biochem. Biophys. Res. Commun. 171, 596-602). We now show directly that the RNase A peptide, with Met replacing Cys 26 to prevent disulfide exchange reactions, strongly induces monocyte-chemotaxis that is blocked by anti-CD4 monoclonal antibody. Both peptide T and RNase A fail to induce chemotaxis, however, in neutrophils which do not express surface CD4 receptors. These results suggest that both peptides interact with the CD4 receptor in inducing monocyte chemotaxis. We have also prepared cyclo-RNase A peptide with Met 26. Using molecular dynamics and conformational energy calculations, we find that the cyclic peptide cannot form a bend structure involving Ser 22-Tyr 25 that is superimposable on the RNase A bend.(ABSTRACT TRUNCATED AT 250 WORDS)

Male rat copulation following 6-OHDA lesions of the medial preoptic area: resistance to repeated administration and rapid behavioral recovery

Dopamine (DA) in the medial preoptic area (MPOA) has been shown to facilitate male rat sexual behavior. However, injections of the catecholamine (CA) neurotoxin 6-OHDA into the MPOA did not impair copulation in tests 3 days after injection. In the present study, three weekly (serial) injections produced no copulatory deficits compared to animals that received a single injection or to preinjection copulatory behavior scores. However, blocking CA synthesis, which did not impair control rats, produced deficits in both single and serial lesion animals, with significantly fewer serial than single lesion animals initiating copulation. Biochemical analysis of tissue punches showed no difference in MPOA concentrations of dopamine, norepinephrine, epinephrine, or the dopamine metabolite DOPAC between the two groups. Additional animals were tested at earlier intervals after 6-OHDA injections into the MPOA. Tests conducted 30 min after an MPOA injection of 6-OHDA revealed that all measures of copulation were impaired, relative to scores 24 h later. However, these scores were not significantly different from animals tested 30 min after a vehicle injection. A final group, tested 4 h after injection, showed impairment of all measures of copulation compared to vehicle injections and to tests 24 h later. Furthermore, in the tests 24 h later, 6-OHDA animals were not different from vehicle animals. Results from all experiments show that 6-OHDA injections into the MPOA impair copulation for at least 4 h, but that behavioral recovery is complete 24 h later. However, deficits can be reinstated by inhibiting DA synthesis, suggesting that increased synthesis in undamaged terminals contributed to behavioral recovery.

Molecular cloning and characterization of the mouse UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I gene

The biosynthesis of protein-bound complex N-glycans in mammals requires a series of covalent modifications governed by a large number of specific glycosyltransferases and glycosidases. The addition of oligosaccharide to an asparagine residue on a nascent polypeptide chain begins in the endoplasmic reticulum. Oligosaccharide processing continues in the Golgi apparatus to produce a diversity of glycan structures. UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (EC 2.4.1.101; GlcNAc-TI) is a key enzyme in the process because it is essential for the conversion of high-mannose N-glycans to complex and hybrid N-glycans. We have isolated the mouse gene encoding GlcNAc-TI (Mgat-1) from a genomic DNA library. The mouse sequence is highly conserved with respect to the human and rabbit homologs and exists as a single protein-encoding exon. Mgat-1 was mapped to mouse Chromosome 11, closely linked to the gene encoding interleukin-3 by the analysis of multilocus interspecies backcrosses. RNA analyses of Mgat-1 expression levels revealed significant variation among normal tissues and cells.

Organization and localization to chromosome 5 of the human UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I gene

UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (GlcNAc-T I; EC 2.4.1.101) is a medial-Golgi enzyme essential for the synthesis of hybrid and complex N-glycans. We have isolated two overlapping genomic DNA clones which span 18 kilobases (kb) containing a single 2.5 kb exon for GlcNAc-T I. The exon includes most of the 5'-untranslated region, the complete coding sequence (1335 bases) for GlcNAc-T I (445 amino acids) and the complete 3'-untranslated region. The remaining exon (or exons) is at least 2.0 kb upstream of the intron-exon junction. Transient transfection of either clone into Lec 1 Chinese hamster ovary cell mutants (which lack GlcNAc-T I) indicates the presence of a promoter responsible for expression of a truncated transcript. Southern blot analysis indicates that the gene exists in single copy in the human genome and is located on chromosome 5. The human and rabbit enzymes are 85% similar at the nucleotide sequence level and 92% similar at the amino acid sequence level.

Molecular cloning and expression of cDNA encoding the enzyme that controls conversion of high-mannose to hybrid and complex N-glycans: UDP-N-acetylglucosamine: alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I

UDP-GlcNAc:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (GnT I; EC 2.4.1.101) catalyzes an essential first step in the conversion of high-mannose N-glycans to hybrid and complex N-glycans. Cloning of the gene encoding this enzyme was carried out by mixed oligonucleotide-primed polymerase chain reaction amplification of rabbit liver single-stranded cDNA using sense and antisense 20- to 24-base-pair (bp) primers. A rabbit liver library in phage lambda gt10 yielded a 2.5-kilobase (kb) cDNA with a 447-amino acid coding sequence. None of the nine asparagine residues were in an Asn-Xaa-(Ser or Thr) sequence, indicating that the protein is not N-glycosylated. There is no sequence homology to other previously cloned glycosyltransferases, but GnT I appears to have a domain structure typical of these enzymes--i.e., a short amino-terminal domain, a transmembrane domain, a "neck" region, and a large carboxyl-terminal catalytic domain. RNA was transcribed off the 2.5-kb cDNA, and in vitro translation with rabbit reticulocyte lysate yielded a 52-kDa protein with GnT I activity.

Control of glycoprotein synthesis. Detection and characterization of a novel branching enzyme from hen oviduct, UDP-N-acetylglucosamine:GlcNAc beta 1-6 (GlcNAc beta 1-2)Man alpha-R (GlcNAc to Man) beta-4-N-acetylglucosaminyltransferase VI

Hen oviduct membranes were shown to contain high activity of a novel enzyme, UDP-GlcNac:GlcNAc beta 1-6(GlcNAc beta 1-2) Man alpha-R (GlcNAc to Man) beta 4-GlcNAc-transferase VI. The enzyme was shown to transfer GlcNAc in beta 1-4 linkage to the D-mannose residue of GlcNAc beta 1-6 (GlcNAc beta 1-2) Man alpha-R where R is either 1-6Man beta-(CH2)8COOCH3 or methyl. Radioactive enzyme products were purified by several chromatographic steps, including high performance liquid chromatography, and structures were determined by proton nmr, fast atom bombardment-mass spectrometry, and methylation analysis to be GlcNAc beta 1-6 ([14C]GlcNAc beta 1-4) (GlcNAc beta 1-2) Man alpha-R. The enzyme is stimulated by Triton X-100 and has optimum activity at a relatively high MnCl2 concentration of about 100 mM; Co2+, Mg2+, and Ca2+ could partially substitute for Mn2+. A tissue survey demonstrated high GlcNAc-transferase VI activity in hen oviduct and lower activity in chicken liver and colon, duck colon, and turkey intestine. No activity was found in mammalian tissues. Hen oviduct membranes cannot act on GlcNAc beta 1-6Man alpha-R but have a beta 4-GlcNAc-transferase activity that converts GlcNAc beta 1-2Man alpha-R to GlcNAc beta 1-4(GlcNAc beta 1-2) Man alpha-R where R is either 1-6Man beta-(CH2)8COOCH3 or 1-6Man beta methyl. The latter activity is probably due to GlcNAc-transferase IV which preferentially adds GlcNAc in beta 1-4 linkage to the Man alpha 1-3 arm of the GlcNAc beta 1-2Man alpha 1-6(GlcNAc beta 1-2Man alpha 1-3)Man beta 1-4GlcNAc beta 1-4GlcNAc-Asn core structure of asparagine-linked glycans. The minimum structural requirement for a substrate of beta 4-GlcNAc-transferase VI is therefore the trisaccharide GlcNAc beta 1-6(GlcNAc beta 1-2) Man alpha-; this trisaccharide is found on the Man alpha 6 arm of many branched complex asparagine-linked oligosaccharides. The data suggest that GlcNAc-transferase VI acts after the synthesis of the GlcNAc beta 1-2Man alpha 1-3-, GlcNAc beta 1-2Man alpha 1-6-, and GlcNAc beta 1-6 Man alpha 1-6-branches by GlcNAc-transferases I, II, and V, respectively, and is responsible for the synthesis of branched oligosaccharides containing the GlcNAc beta 1-6(GlcNAc beta 1-4)(GlcNAc beta 1-2)Man alpha 1-6Man beta moiety.

Adult responsiveness to ultrasonic signals from gerbils of varying ages: parity, gender, and housing effects

Groups of adult gerbils differing by gender, parity, and presence or absence of young in the nest were exposed to taped ultrasonic distress calls of male and female pups on postnatal Days 3, 8, and 13. Frequency and time spent performing several behavioral items as well as frequency and time spent in the compartment housing the recorded tapes were assessed in the adult groups. Adult groups differed in rates and durations of certain behavioral items only during playback, with females with young in the home nest exhibiting the highest frequency of nest building in the test apparatus. However, all groups spent more time in the arm from which calls of Day-8 pups were played. Calls of Day-3 and Day-13 pups did not produce significant differences in adult responsiveness. These results reveal significant characteristics of the ultrasounds for each group which parallel certain morphological and behavioral changes.