Incidence and duration of romantic attraction in students progressing from secondary to tertiary education

There is increasing interest in the nature and biological significance of romantic love but few quantitative data are available for testing specific hypotheses. This paper describes the use of a survey instrument to assess incidence and duration of romantic attractions over a 2-year period amongst students (121 male; 162 female) progressing from school to university education. The results for males and females were similar and schooling single-sex or co-educational--had little effect. Students averaged 1.45 romantic episodes per year and 93% of students reported at least one episode over the survey period. Duration of attraction was around 9 weeks if never reciprocated and around 12 weeks if reciprocated. There was seasonal variation of onset of episodes with peak incidence over the summer or early autumn seasons. Collectively the results accord with the view that frequent, short-duration romantic episodes could have a role in selection of appropriate long-term reproductive partnerships.     

2,4-dichlorophenoxyacetate/alpha-ketoglutarate dioxygenases from Burkholderia cepacia 2a and Ralstonia eutropha JMP134

2,4-Dichlorophenoxyacetate (2,4-D)/alpha-ketoglutarate (alpha-KG) dioxygenase has been purified to apparent homogeneity from Burkholderia cepacia strain 2a, which utilizes 2,4-D as sole carbon source. The enzyme required ferrous ions, and was a homodimer composed of subunits having an Mr of approximately 32,000. The reaction catalysed consumed one mol each of 2,4-D, alpha-KG and dioxygen, with the production of one mol each of succinate, 2,4-dichlorophenol and glyoxylate. Maximum activity was exhibited at pH 7.8 and 25 degrees C, and reactivity was enhanced by the presence of ascorbate and cysteine. Mn2+, Zn2+, Cu2+, Fe3+ and Co2+ were inhibitory, and chemical modification of the dioxygenase revealed that thiol groups were essential for activity. The enzyme was active towards other substituted phenoxyacetates, but reacted most rapidly with 2,4-D. The apparent Michaelis constants for 2,4-D and alpha-KG were 109 and 8.9 microM, respectively. The properties of this enzyme are compared with those of the 2,4-D/alpha-KG dioxygenase from Ralstonia eutropha JMP134, which exhibits a differing N-terminal amino-acid sequence, and a different temperature 'optimum', pH optimum, substrate specificity and sensitivity to thiol-binding reagents.     

Concentration and Mindfulness Meditations: Unique Forms of Consciousness?

Electroencephalographic (EEG) recordings from 19 scalp recording sites were used to differentiate among two posited unique forms of mediation, concentration and mindfulness, and a normal relaxation control condition. Analyzes of all traditional frequency bandwidth data (i.e., delta 1–3 Hz; theta, 4–7 Hz; alpha, 8–12 Hz; beta 1, 13–25 Hz; beta 2, 26–32 Hz) showed strong mean amplitude frequency differences between the two meditation conditions and relaxation over numerous cortical sites. Furthermore, significant differences were obtained between concentration and mindfulness states at all bandwidths. Taken together, our results suggest that concentration and mindfulness meditations may be unique forms of consciousness and are not merely degrees of a state of relaxation.     

alpha-Synuclein A53T substitution associated with Parkinson disease also marks the divergence of Old World and New World primates

The alpha-synuclein mutation Ala53Thr is associated with increased oligomerization, toxicity, and early onset Parkinson disease in humans, but 53Thr is the normal residue in other species. Comparative sequencing of SNCA genes shows that 53Ala marks the divergence of Old World and New World primates, in an otherwise constrained protein region. These results have implications for interpreting Parkinson disease models and suggest that other long-lived mammals have different mechanisms to forestall alpha-synucleinopathy.     

Doublecortin microtubule affinity is regulated by a balance of kinase and phosphatase activity at the leading edge of migrating neurons

Doublecortin (Dcx) is a microtubule-associated protein that is mutated in X-linked lissencephaly (X-LIS), a neuronal migration disorder associated with epilepsy and mental retardation. Although Dcx can bind ubiquitously to microtubules in nonneuronal cells, Dcx is highly enriched in the leading processes of migrating neurons and the growth cone region of differentiating neurons. We present evidence that Dcx/microtubule interactions are negatively controlled by Protein Kinase A (PKA) and the MARK/PAR-1 family of protein kinases. In addition to a consensus MARK site, we identified a serine within a novel sequence that is crucial for the PKA- and MARK-dependent regulation of Dcx's microtubule binding activity in vitro. This serine is mutated in two families affected by X-LIS. Immunostaining neurons with an antibody that recognizes phosphorylated substrates of MARK supports the conclusion that Dcx localization and function are regulated at the leading edge of migrating cells by a balance of kinase and phosphatase activity.     

Cortical development deNUDEd

The development of the cerebral cortex is a highly orchestrated process of cell division and migration. In this issue of Neuron, Feng and Walsh and Shu et al. examine the roles of two related proteins, Nde1 (mNudE) and Ndel1 (NUDEL), in cortical development. These proteins play a crucial role in centrosome positioning, with Nde1 functioning mainly during progenitor cell divisions and Ndel1 functioning in neuronal migration.     

Functional effects of enhancing or silencing adenosine A2b receptors in cardiac fibroblasts

Cardiac fibroblasts (CF) express adenosine (ADO) receptors, and pharmacological evidence suggests the possible involvement of the A2 (A2a and A2b) receptor (A2aR and A2bR) subtypes in inhibiting cell functions involved in fibrosis. The main objective of this study was to define the contributions of A2a and/or A2b receptors in modulating ADO-induced decreases in CF functions. For this purpose, CF were either treated pharmacologically or had the A2aR or A2bR levels modified through the use of recombinant adenovirus or siRNA. The assessment of mRNA expression in adult rat CF yielded evidence for A1R, A2bR, A2a), and A3R. Endogenously or exogenously enhanced ADO significantly inhibits CF proliferation, collagen, and protein synthesis. A2R and A2aR agonists, although capable of inhibiting CF protein and collagen synthesis, were unable to define the contributions derived from A2aR or A2bR. Overexpression of A2bR in CF yielded significant decreases in basal levels of collagen and protein synthesis and correlated with increases in cAMP levels. However, at higher doses of ADO receptor agonists, significant increases in protein and collagen synthesis were observed. CF with underexpression of A2bR yielded increases in protein and collagen synthesis. In contrast, A2aR underexpression did not modify ADO-induced decreases in CF protein or collagen synthesis. In conclusion, results derived from the molecular manipulation of receptor levels indicate that A2bR are critically involved in ADO-mediated inhibition of CF functions.     

5-lipoxygenase and cyclooxygenase regulate wound closure in NIH/3T3 fibroblast monolayers

Wound healing involves multiple cell signaling pathways, including those regulating cell-extracellular matrix adhesion. Previous work demonstrated that arachidonate oxidation to leukotriene B₄ (LTB₄) by 5-lipoxygenase (5-LOX) signals fibroblast spreading on fibronectin, whereas cyclooxygenase-2 (COX-2)-catalyzed prostaglandin E₂ (PGE₂) formation facilitates subsequent cell migration. We investigated arachidonate metabolite signaling in wound closure of perturbed NIH/3T3 fibroblast monolayers. We found that during initial stages of wound closure (0–120 min), all wound margin cells spread into the wound gap perpendicularly to the wound long axis. At regular intervals, between 120 and 300 min, some cells elongated to project across the wound and meet cells from the opposite margin, forming distinct cell bridges spanning the wound that act as foci for later wound-directed cell migration and resulting closure. 5-LOX inhibition by AA861 demonstrated a required LTB₄ signal for initial marginal cell spreading and bridge formation, both of which must precede wound-directed cell migration. 5-LOX inhibition effects were reversible by exogenous LTB₄. Conversely, COX inhibition by indomethacin reduced directed migration into the wound but enhanced early cell spreading and bridge formation. Exogenous PGE₂ reversed this effect and increased cell migration into the wound. The differential effects of arachidonic acid metabolites produced by LOX and COX were further confirmed with NIH/3T3 fibroblast cell lines constitutively over- and underexpressing the 5-LOX and COX-2 enzymes. These data suggest that two competing oxidative enzymes in arachidonate metabolism, LOX and COX, differentially regulate sequential aspects of fibroblast wound closure in vitro. leukotriene B₄; prostaglandin E₂; spreading; migration; bridges