Isolation and characterization of a heparin with high anticoagulant activity from Anomalocardia brasiliana

The isolation, some structural features, physicochemical properties and pharmacological activities of a heparin from Anomalocardia brasiliana are reported. It is shown that the mollusc heparin is very similar to those present in mammalian tissues with regard to chemical composition, physicochemical properties, pharmacological activities and susceptibility to heparinase and heparitinase II from Flavobacterium heparinum, as well as to the types of products formed by the action of these enzymes. Three significant quantitative differences were observed for the mollusc heparin when compared with the ones from mammalian origin, namely, a higher degree of binding with antithrombin III (45%), higher molecular weight (27-43 kDa) and higher anticoagulant activity (320 I.U./mg). The possible biological role of heparin is discussed in view of the present findings.     

Lung volumes, chest wall configuration, and pattern of breathing in microgravity

We studied the changes in functional residual capacity (FRC), thoracoabdominal volume (Vw), and chest wall configuration in five normal subjects seated in an aircraft flying parabolic trajectories resulting in 20-s periods of microgravity. We measured vital capacity (VC), inspiratory capacity, and tidal volume by integrating airflow at the mouth and changes in rib cage and abdominal volume (delta Vrc and delta Vab, respectively, where delta Vrc + delta Vab = delta Vw) using induction plethysmography. During microgravity (0 Gz) FRC decreased by 413 +/- 70 (SE) ml and VC by 0.37 liter. The decrease in Vw did not differ from that in FRC and was entirely the result of reduction of Vab, the Vrc showing no significant change. During tidal breathing the abdominal contribution (delta Vab/delta Vw) increased from 0.39 +/- 0.08 at 1 Gz to 0.57 +/- 0.08 at 0 Gz. During brief periods of hypergravity (approximately 1.8 Gz) all changes were opposite in sign and relatively smaller. Limited data during "roller coaster" flight patterns suggested that, in contrast to configurational changes, the temporal pattern of breathing was uninfluenced by changes in Gz. We conclude that at the onset of weightlessness there are substantial changes in lung volume and thoracoabdominal configuration. Abdominal contribution to tidal excursions increases but the temporal pattern of breathing is unchanged.     

Plenty of rooftops with few neighbours occupied by young breeding Yellow-legged Gulls (Larus michahellis): Does this occur at the expense of their health condition?

Gulls, as largely flexible opportunistic individuals, have been increasingly breeding in many cities around the world, but it is still unclear whether urban habitats are of equal or higher quality than traditional natural habitats or represent an ecological trap with immediate reproductive benefits but longer-term detrimental consequences to health. Here we present a study of breeding parameters (nest density, egg dimensions, clutch size, hatching success and adult body condition) and physiological parameters (erythrocyte sedimentation rate, heterophil/lymphocyte ratio, haemoglobin concentration and measurements of oxidative stress) as indicators of the general health condition of Yellow-legged Gull Larus michahellis adults and chicks from natural and urban colonies. Yellow-legged Gulls in the largest urban area (Porto) laid smaller eggs and clutches, showed a significantly lower occurrence of inflammatory processes in chicks, and showed a slower early chick growth than in the natural colony of Deserta. This suggests that urban gulls might be facing important trade-offs between the advantages of breeding in lower density urban colonies, with fewer intraspecific interactions and a lower disease transmission probability, and the disadvantages of having an anthropogenic diet usually lower in nutritional value.     

Bioreactors for surface-immobilized cells

Surface immobilization of plant cells avoids the problem of hydrodynamic or shear stress, which tends to be characteristic of suspended cells cultured in typical, mechanically agitated bioreactor systems. Surface immobilization also promotes the natural tendency for plant cells to aggregate, which may improve the synthesis and accumulation of secondary metabolites. In addition, exchange of medium is made simple in surface-immobilized systems, and extracellular secondary products are easily recovered on a continuous basis. However, problems related to regulation of the thickness of the immobilized cell layer, maintenance of the biomass in a productive condition, and vacuolar retention of secondary products have yet to be resolved satisfactorily. This review focusses on two surface-immobilization technologies, differing primarily in the nature and the configuration of the inert support. Prototypes of these designs have been applied to a variety of plant cell systems at bioreactor volumes up to 20 litres. Results obtained with several alternative technologies are also summarized.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - SIPCB surface-immobilized plant cell bioreactor National Research Council of Canada publication no. 38460     

Ventilation distribution during histamine provocation

Verbanck, S., D. Schuermans, A. Van Muylem, M. Paiva, M. Noppen, and W. Vincken. Ventilation distribution during histamine provocation. J. Appl. Physiol. 83(6):1907-1916, 1997.We investigated ventilation inhomogeneity duringprovocation with inhaled histamine in 20 asymptomatic nonsmokingsubjects. We used N₂multiple-breath washout (MBW) to deriveparameters S_condand S_acin as ameasurement of ventilation inhomogeneity in conductive and acinar zonesof the lungs, respectively. A 20% decrease of forced expiratory volume in 1 s (FEV₁) was used todistinguish responders from nonresponders. In the responder group,average FEV₁ decreased by 26%,whereas S_condincreased by 390% with no significant change inS_acin. In thenonresponder group, FEV₁ decreasedby 11%, whereasS_cond increased by 198% with no significantS_acin change.Despite the absence of change inS_acin duringprovocation, baselineS_acin wassignificantly larger in the responder vs. the nonresponder group. Themain findings of our study are that during provocation largeventilation inhomogeneities occur, that the small airways affected bythe provocation process are situated proximal to the acinar zone wherethe diffusion front stands, and that, in addition to overall decreasein airway caliber, there is inhomogeneous narrowing of parallelairways.

     

Spatial and temporal gene expression patterns occur during corm development.

We investigated gene expression patterns that occur during taro corm development. Two-dimensional gel electrophoresis identified several different prevalent proteins that accumulate during corm development. Microsequencing studies indicated that some of these proteins are related to taste-modifying proteins, such as curculin and miraculin, and proteins found in other storage organs, such as sporamin and the Kunitz trypsin inhibitor. A curculin-encoding cDNA clone, designated as TC1, was identified that corresponds to a highly prevalent 1-kb corm mRNA. The TC1 mRNA accumulates during corm development, is more prevalent in corm apical than basal regions, and is either absent, or present at low concentrations, in other vegetative organs such as the leaf and root. In situ hybridization experiments showed that the TC1 mRNA is highly concentrated in corm storage parenchyma cells and is absent, or present in reduced concentrations, in other corm cells and tissues. Our results show that corm development is associated with the differentiation of specialized cells and tissues, and that these differentiation events are coupled with the temporal and spatial expression of corm-specific genes.     

Characterization of F-pilin as an inner membrane component of Escherichia coli K12.

Antipeptide antibodies were used to detect, purify, and characterize nonfilament F-pilin in the cell envelope of an F'tra+ strain of Escherichia coli. Affinity-purified goat antibodies raised against a peptide corresponding to the amino-terminal 14 amino acids of F-pilin detected F-pilin in immuno-overlay ("Western") blots of electrophoretically separated inner and outer membrane proteins. As expected, the molecule was absent from inner membrane preparations of F- or F'traA[Am] strains. Immunoreactive material was purified from inner membrane fractions and shown to be F-pilin by amino acid analysis. The anti-peptide antibodies also detected membrane forms of F-pilin produced by cells containing plasmid pTG801 (Grossman, T. & Silverman, P. (1989) J. Bacteriol. 171, 650-656). Most cell envelope pilin was in the inner membrane fraction, but a significant quantity fractionated with the outer membrane as well. The hydropathy profile of F-pilin suggested that the molecule is an integral membrane protein with two membrane-spanning domains. In confirmation, F-pilin and pTG801 pilins in inner membrane preparations were solubilized by a single extraction with the nonionic detergents Nonidet P-40 (2%) or Triton X-100 (2%), but not by 2 M KCl or 0.1 M NaOH. Moreover, analysis of traA'-'phoA constructs indicated that both the amino and carboxyl termini of F-pilin face the periplasm. The periplasmic location of the amino terminus was confirmed by immunoelectron microscopy of spheroplasts from F' and pTG801 strains, using a monoclonal antibody that recognizes an amino-terminal epitope. These data suggest a specific structure for membrane F-pilin. We discuss that structure in relation to the probable structure of filament F-pilin.     

Mechanical implications of in vivo human diaphragm shape.

Using magnetic resonance imaging, we measured the three-dimensional form of the diaphragm in vivo in four supine relaxed subjects at functional residual capacity and calculated its total surface area, the right and left surface areas in the zone of apposition, and the principal radii of curvature as a function of height. The area of apposition comprised 45 +/- 1.5% (SE) of the total surface area of the diaphragm. Available data on the area of the central tendon indicate that a considerable part of the muscular part of the diaphragm is lung apposed. The curvature was linearly related to height over 7 cm of the posterior half of each hemidiaphragm. From the linear portion of this graph and assuming a vertical gradient of transdiaphragmatic pressure of 0.75 cmH2O/cm, we applied the Laplace law and calculated tensions of 54 and 32 g/cm for right and left sides, respectively. We conclude that the shape of at least part of the posterior half of the relaxed human diaphragm in the supine position at functional residual capacity can be explained by the Laplace law, suggesting that both the lung and abdominal contents behave sufficiently as fluids so that they do not impose their shape on the diaphragm. Because diaphragm muscle is partly lung apposed, it is unlikely that the diaphragm functions simply as a piston.