Apolipoprotein A-I decreases neutrophil degranulation and superoxide production.

Neutrophils participate in the acute phase response and are often associated with tissue injury in a number of inflammatory disorders. The acute phase response is accompanied by alterations in the metabolism of apolipoprotein A-I and high density lipoprotein (HDL). Structural considerations led to studies investigating the effect of purified HDL and apolipoprotein A-I on neutrophil degranulation and superoxide production. Apolipoprotein A-I but not HDL inhibited IgG-induced neutrophil activation by about 60% as measured by degranulation and superoxide production. This suggests that the lipid-associating amphipathic helical domains of apolipoprotein A-I mediate this effect. In support of this was finding inhibitory effects with two synthetic model lipid-associating amphipathic helix peptide analogs. Apolipoprotein A-I, containing tandem repeating amphipathic helical domains, was approximately ten times more effective than the two peptide analogs and inhibited neutrophil activation at well below physiologic concentrations. Competitive binding studies indicate that resting neutrophils have approximately 190,000 (Kd = 1.7 x 10(-7)) binding sites per cell for apolipoprotein A-I, consistent with a ligand-receptor interaction. These observations suggest that apolipoprotein A-I may play an important role in regulating neutrophil function during the inflammatory response.     

Tel-1 Transposon-like Elements of Tetrahymena Thermophila Are Associated with Micronuclear Genome Rearrangements

The micronuclear genome of Tetrahymena thermophila contains Tel-1 elements that structurally resemble transposons. Here we present molecular evidence that Tel-1 transposon-like elements are mobile. The arrangements of Tel-1 elements in the micronuclear genomes of several T. thermophila strains and cell lines were assayed by Southern blotting. The molecular evidence for Tel-1 transposition is most striking in strains that have undergone unusual laboratory-induced meioses. The genetic history of the strains exhibiting evidence of Tel-1 transposition is consistent with periods of genome restructuring in response to genomic ``shock' that B. McClintock has suggested could result in transposon activation.     

Morphine and Cocaine Exert Common Chronic Actions on Tyrosine Hydroxylase in Dopaminergic Brain Reward Regions

We studied levels of tyrosine hydroxylase immunoreactivity and phosphorylation state in the ventral tegmental area (VTA) and nucleus accumbens (NAc) in an effort to understand better the mechanisms by which these brain reward regions are influenced by opiates and cocaine. In the VTA, chronic, but not acute, administration of either morphine or cocaine increased levels of tyrosine hydroxylase immunoreactivity by 30-40%, with no change observed in the relative phosphorylation state of the enzyme. In the NAc, chronic, but not acute, morphine and cocaine treatments decreased the phosphorylation state of tyrosine hydroxylase, without a change in its total amount. In contrast, morphine and cocaine did not regulate tyrosine hydroxylase in the substantia nigra or caudate/putamen, brain regions generally not implicated in drug reward. Morphine and cocaine regulation of tyrosine hydroxylase could represent part of a common biochemical basis of morphine and cocaine addiction and craving.     

Arboriculture in the Mussau Islands,Bismarck Archipelago

The Mussau Islanders of the Bismarck Archipelago in northeastern Papua New Guinea cultivate 26 indigenous tree species both for food and non-food uses in tree gardens surrounding the villages. Several trees which volunteer in these arboriculture zones are also tended and encouraged. I present ethnobotanical information on methods of cultivation, how and when the trees are harvested, preparation and use. The tree crop zone has a random spatial distribution overall, but some species within the zone are aggregated spatially. This clumping is related to the restricted habitat requirements of certain species, as well as individual species ’ reproductive traits. Coconut is the most frequent species in the arboriculture zone and is randomly distributed. Vertical stratification is attributable to the presence of a distinct herb layer and a subcanopy stratum of maturePandanus spp. The stratification of some species pairs results from the deliberate planting of subcanopy trees next to canopy trees. The introduction of exotic garden species and the increasing availability of western packaged foods is changing the composition of traditional Mussau Islands tree gardens.     

Reduced susceptibility to HIV-1 infection of ethyl-methanesulfonate-treated CEM subclones correlates with a blockade in their protein kinase C signaling pathway.

We have described the isolation of chemically induced CEM subclones that express CD4 receptors and bind soluble gp120, yet show a markedly reduced susceptibility to infection with HIV-1. Two subclones were found to have an abnormal response to the protein kinase C (PKC) activator PMA. PMA treatment induced CD3 and CD25 (IL-2R) receptors on the parental line and on other ethyl-methanesulfonate-derived subclones, but not on these two mutants. Direct assays of PKC activity were conducted. Total cellular PKC enzymatic activity was found to be normal in these subclones. PMA-induced CD4 down-modulation occurred normally. In addition, activation of c-raf kinase was normal. Since HIV-1 long terminal repeat contains two functional nuclear factor kB (NF-kB) regulatory elements, we studied the ability of PMA to induce NF-kB binding activity by different assays. Chloramphenicol acetyl transferase (CAT) assays using the HIV-1 (-139)long terminal repeat-CAT construct showed no PMA induction of CAT activity in these subclones (unlike the parental line and other subclones). Okadaic acid, an inhibitor of phosphatases 1 and 2A, did not overcome the defect in these subclones. Gel retardation assays, using a 32P-probe containing the HIV-1 NF-kB probe and nuclear extracts from PMA-treated cells, showed significantly reduced induction of nuclear NF-kB binding proteins in these two subclones compared with wild type CEM and a control subclone. Deoxycholate treatment of cytoplasmic extracts from these subclones released much reduced NF-kB binding proteins from their cytoplasmic pools. Thus, reduced levels of PKC-induced nuclear NF-kB activity in two T cell subclones did not affect their normal cell growth, but correlated with a pronounced reduction in their susceptibility to HIV-1 infection.     

Artemia monica cyst production and recruitment in Mono Lake,California, USA

Annual egg production was determined for Artemia monica in Mono Lake, California, from 1983 to 1987. Annual oviparous (overwintering cyst) production was 3 and 7 million cysts m^–2 yr^–1 in 1986 and 1987, respectively, as measured by in situ sediment traps. Cyst production for the entire five year period was calculated using Artemia census data and inter-brood duration derived from mixolimnetic temperature. These estimates ranged from 2 to 5 million cysts m^–2 yr^–1. This method underestimated annual production by 30%, when compared to estimates using sediment traps. Cyst production was similar during 1983–1986 and showed a significant increase in 1987, which was due primarily to a larger reproductive population later in the year. Recruitment into the adult populations of the following spring ranged between 1.4 to 3.2%. Overall abundance of this generation reflected the patterns in annual cyst production. Compensatory effects must operate on the second generation of each year, since summer populations were similar in all years despite differences in cyst production.     

Characterization of a carbon monoxide complex of reduced dopamine beta-hydroxylase. Evidence for inequivalence of the Cu(I) centers

Ascorbate-reduced dopamine beta-hydroxylase (DBH) is inhibited by CO in a competitive manner with respect to molecular O2. Measurement of the stoichiometry of CO binding indicates 0.50 CO bound per Cu(I), which provides the first evidence that the Cu(I) centers in the reduced enzyme are structurally inequivalent. FTIR spectroscopy has been used to detect an infrared absorption band characteristic of coordinated CO, with v(CO) = 2089 cm-1. Comparison of this frequency with those of other Cu(I)-carbonyls in both inorganic and protein systems suggests a coordination site with fewer or less basic ligands than the 3-histidine site of carbon-monoxy hemocyanin.     

Structure of tendon organs in fishes of the genus Polymixia

Summary Modified branchiostegal rays 1 through 3 support the proximal end of the paired hyoid barbels in the beardfish (Beryciformes: Polymixiidae). The polymixiid barbel is unusual in that it has an unique intrinsic muscular system. Using silver impregnation and electron microscopic techniques, unencapsulated, free nerve endings were located within the tendon of the third modified branchiostegal ray. Branchiostegal rays 1 and 2 do not have any free nerve endings associated with their tendons, however. It is suggested that the free nerve endings are proprioceptors acting as stretch-sensitive mechanoreceptors, and that branchiostegal ray 3 acts as part of a sensory apparatus for monitoring the positional state of the barbel. Branchiostegal rays 1 and 2 merely provide support for the barbel.Abbreviations used in Figures BA barbel - br r 3 branchiostegal ray 3 - IM intermandibularis - IOP interoperculum - LIM interoperculomandibular ligament - MD mandible - MX maxilla - OP operculum - PM premaxilla - POP preoperculum - SOP suboperculum     

Transposition of the kanamycin-resistance transposon Tn903

Summary The insertion of the kanamycin-resistance transposon, Tn903, into the Escherichia coli chromosome was studied. Tn903 is similar in structure to the well known transposons Tn5 and Tn10 in that it has a unique central sequence flanked by inverted repeat sequences extending more than a thousand base pairs. However, the central region of Tn903 has enough single-frame coding capacity only for the drug modifying enzyme, whereas Tn5 and Tn10 carry multigenic unique sequences. In this paper we demonstrate that two different classes of insertion event occur: (1) the first class is a complex event in which all or part of the genome of the bacteriophage lambda vector is co-inserted near the purE locus on the E. coli chromosome (11.7 min); (2) the second class appears to be a simple transposition event in which the transposon alone is inserted at relatively nonspecific sites in the chromosome, as has been described for Tn5 and Tn10. Furthermore both classes show dependency on homology-requiring recombination systems. We suggest that Tn903 transposes infrequently because it must utilize a recA-controlled host function, whereas Tn5 and Tn10 are recA-independent and encode similar but more active functions on the transposon DNA.     

Lectin induction of lymphokines in cultured murine leukocytes

Antigens induce sensitized lymphocytes to undergo mitosis and to secrete soluble products, termed lymphokines, which modulate the immune response. Plant lectins are known to act as polyclonal lymphocyte mitogens and, in some cases, stimulate lymphocytes to produce lymphokines. In an effort to explore the relationship of specific cell surface glycoconjugates to the induction of mitosis and the production of lymphokine activities we have examined the ability of the mitogenic lectins, concanavalin A and Wistaria floribunda mitogen, and the nonmitogenic hemagglutinin from Wistaria floribunda seeds to stimulate the production of macrophage migration inhibition factor (MIF), macrophage chemotactic factor (CF), and lymphotoxin (LT). Concanavalin A causes lymphocytes to produce MIF and LT but no detectable CF activities. W. floribunda mitogen induces lymphocytes to produce soluble substances which exhibit all three lymphokine activities. The nonmitogenic W. floribunda agglutinin causes lymphocytes to produce MIF and CF but no observable LT activity. Within the sensitivity of the assays employed, the results indicate that mitogenesis is not a corequisite of the expression of either macrophage migration inhibition factor or lymphocyte-derived chemotactic factor but it may be associated with the induction of lymphotoxin. It is also apparent that the expression of each lymphokine activity is independent of the expression of the other lymphokines studied.