Pollen morphology of the Bignoniaceae from a south Brazilian Atlantic forest

The pollen morphology of 33 species (19 genera) of Bignoniaceae native to the south Brazilian Atlantic forest was examined using light- and scanning electron microscopy. The following pollen types were established: 1. inaperturate (Adenocalymma, Clytostoma and Pithecoctenium) 2. triaperturate (A) psilate (Jacaranda) (B) microreticulate (Arrabidaea, Fridericia, Lundia, Macfadyena, Melloa, Paragonia, Schlegelia and Tynnanthus) (C) reticulate (Cybistax, Pyrostegia and Tabebuia), 3. stephanocolpate (Amphilophium, Anemopaegma and Urbanolophium), 4. perisyncolpate (Mansoa).     

Discovery of potent,selective, bioavailable phosphodiesterase 2 (PDE2) inhibitors active in an osteoarthritis pain model,Part I: Transformation of selective pyrazolodiazepinone phosphodiesterase 4 (PDE4) inhibitors into selective PDE2 inhibitors

We identified potent, selective PDE2 inhibitors by optimizing residual PDE2 activity in a series of PDE4 inhibitors, while simultaneously minimizing PDE4 activity. These newly designed PDE2 inhibitors bind to the PDE2 enzyme in a cGMP-like mode in contrast to the cAMP-like binding mode found in PDE4. Structure activity relationship studies coupled with an inhibitor bound crystal structure in the active site of the catalytic domain of PDE2 identified structural features required to minimize PDE4 inhibition while simultaneously maximizing PDE2 inhibition.     

Neck muscle vibration disrupts steering of locomotion.

Neck muscle vibration was applied to human subjects to assess the influences of neck abnormal proprioceptive input on the organization and execution of gait. Subjects walked blindfolded to a previously seen target, located straight ahead at ~4 m. Vibration was applied on the right side of the neck, both during and before walking. The variables measured were length, duration, and velocity of trajectory; relative and absolute frontal errors at target; and width of walking support base. Vibration applied during locomotion produced an undershoot of target and deviation of gait trajectory toward the side opposite to vibration. Vibration applied before locomotion produced no effect on length of trajectory but slowing of velocity and nonsystematic deviation. When vibration frequency was increased, the amplitude of the nonsystematic deviation increased. Vibration applied during or before stance trials had minor effects on body sway. Vibration before stance had no effect on the position of mean center of foot pressure, whereas vibration during stance displaced it to the side opposite to the vibrated muscle. We suggest that vibration during locomotion reduces length and velocity of trajectory because of a direct action on the locomotor centers and produces trajectory deviation related to its effect on stance. Vibration before locomotion causes a major, nonsystematic deviation from the planned trajectory, possibly connected to a disorientation of the internal references.     

Canine mastocytoma: report of 8 cases diagnosed by fine needle cytology and clinicopathologic correlations

BACKGROUND: Mast cell proliferations are commoner in dogs than in humans; mass forming lesions in the former are apt to fine needle sampling and the obtained cytopathological picture might be informing to enhance recognition of similar proliferations in humans. CASE: Clinical and cytopathologic data were collected from 8 cases of canine mastocytomas diagnosed by fine needle cytology. The cytopathologic presentation was correlated with the individual therapy performed and with the clinical stage. In all cases the cytopathological diagnosis was confirmed by histopathologic examination of the excised mass, by necropsy or by response to therapy. CONCLUSION: There are marked similarities between canine and human mastocytomas, despite possible differences in the clinical course of the disease in both species. Canine mastocytomas may hence be used as an animal model of a human disease and, as such, familiarity with their cytologic presentation may be useful for recognizing mast cell proliferations in humans.     

Inflammatory levels of nitric oxide inhibit airway epithelial cell migration by inhibition of the kinase ERK1/2 and activation of hypoxia-inducible factor-1 alpha

Increased synthesis of NO during airway inflammation, caused by induction of nitric-oxide synthase 2 in several lung cell types, may contribute to epithelial injury and permeability. To investigate the consequence of elevated NO production on epithelial function, we exposed cultured monolayers of human bronchial epithelial cells to the NO donor diethylenetriaamine NONOate. At concentrations generating high nanomolar levels of NO, representative of inflammatory conditions, diethylenetriaamine NONOate markedly reduced wound closure in an in vitro scratch injury model, primarily by inhibiting epithelial cell migration. Analysis of signaling pathways and gene expression profiles indicated a rapid induction of the mitogen-activated protein kinase phosphatase (MPK)-1 and decrease in extracellular signal-regulated kinase (ERK)1/2 activation, as well as marked stabilization of hypoxia-inducible factor (HIF)-1alpha and activation of hypoxia-responsive genes, under these conditions. Inhibition of ERK1/2 signaling using U0126 enhanced HIF-1alpha stabilization, implicating ERK1/2 dephosphorylation as a contributing mechanism in NO-mediated HIF-1alpha activation. Activation of HIF-1alpha by the hypoxia mimic cobalt chloride, or cell transfection with a degradation-resistant HIF-1alpha mutant construct inhibited epithelial wound repair, implicating HIF-1alpha in NO-mediated inhibition of cell migration. Conversely, NO-mediated inhibition of epithelial wound closure was largely prevented after small interfering RNA suppression of HIF-1alpha. Finally, NO-mediated inhibition of cell migration was associated with HIF-1alpha-dependent induction of PAI-1 and activation of p53, both negative regulators of epithelial cell migration. Collectively, our results demonstrate that inflammatory levels of NO inhibit epithelial cell migration, because of suppression of ERK1/2 signaling, and activation of HIF-1alpha and p53, with potential consequences for epithelial repair and remodeling during airway inflammation.     

Functional genomics in the study of seed germination

Several legume genes involved in establishing nitrogen fixation have been discovered using functional genomics; when mutated, the genes affect symbioses, and all encode receptor kinases. This provides long-awaited insights into a complex plant-bacterium interaction and heralds the possibility of extending the range of plants susceptible to nitrogen-fixing nodulation.     

Coupling of organotypic brain slice cultures to silicon-based arrays of electrodes.

Fetal or early postnatal brain tissue can be cultured in viable and healthy condition for several weeks with development and preservation of the basic cellular and connective organization as so-called organotypic brain slice cultures. Here we demonstrate and describe how it is possible to establish such hippocampal rat brain slice cultures on biocompatible silicon-based chips with arrays of electrodes with a histological organization comparable to that of conventional brain slice cultures grown by the roller drum technique and on semiporous membranes. Intracellular and extracellular recordings from neurons in the slice cultures show that the electroresponsive properties of the neurons and synaptic circuitry are in accordance with those described for cells in acutely prepared slices of the adult rat hippocampus. Based on the recordings and the possibilities of stimulating the cultured cells through the electrode arrays it is anticipated that the setup eventually will allow long-term studies of defined neuronal networks and provide valuable information on both normal and neurotoxicological and neuropathological conditions.     

DNA probes in detection of spiroplasmas and mycoplasma-like organisms in plants and insects

Abstract DNA probes were applied to detect spiroplasmas and uncultivable mycoplasma-like organisms (MLOs) in infected plants and insects. The probes consisted of pMC5, a plasmid carrying the RNA genes of Mycoplasma capricolum and pRA1, a plasmid recovered from Spiroplasma citri . Southern blot hybridization of pMC5 with digested DNAs of periwinkle plants infected with S. citri , or with various MLOs, yielded 2 heavy and several weaker bands. The heavy hybridization bands were shown to represent rRNA genes of the plant chloroplasts, indicating significant nucleotide sequence homology between the mycoplasmal rRNA genes and those of plant chloroplasts. Some of the weaker hybridization bands, not revealed in DNA of healthy plants, appeared to represent rRNA gene sequences of the infectious agent. Use of the spiroplasma plasmid as a probe enabled the detection of S. citri in infected plant material and in hemolymph of infected leafhoppers at a high sensitivity level.