Peroxidase levels in the cotyledons of hazel seed (Corylus avellana)

Peroxidase activity was demonstrated in extracts from hazel cotyledons and the cytoplasmic enzyme was partially characterized. Levels of cytoplasmic and org@tnellar peroxidase were monitored in seeds stratified at 5” and incubated under moist conditions at 20°. Specific activities of the enzymes in both subcellular localizations remain constant throughout nine weeks stratification but show a steady rise in activity from seeds maintained at 20°.     

Glucose-6-phosphate dehydrogenase and 6-phosphogluconic acid dehydrogenase of wild oat seeds

The presence of the initial enzymes of the pentose phosphate pathway, namely glucose-6-phosphate dehydrogenase and 6-phosphogluconic acid dehydrogenase, has been demonstrated in dormant seed of wild oat. Before a partial characterization of these enzymes was made, an inherent NADP-reducing activity and an enzyme deactivating component, both present in the crude extract, were removed by ammonium sulphate precipitation and subsequent desalting. Both enzymes were then shown to be NADP-specific. Typical Michaelis-Menten kinetics were shown by each enzyme towards NADP and their respective substrates. Soluble cytoplasmic dehydrogenase enzymes were present in both embryo and endosperm extracts.     

Shear stress-induced shedding of soluble intercellular adhesion molecule-1 from saphenous vein endothelium

Within 6 h, shear stress upregulated intercellular adhesion molecule-1 (ICAM-1) (two- to four-fold, P<0.001) and induced matrix metalloproteinase-2 (MMP-2) in cultured human saphenous vein endothelial cells. By 8 h endothelial ICAM-1 levels returned to baseline, with concomitant increase in soluble ICAM-1 (sICAM-1) (P<0.001) and MMP-9 had been induced. Inclusion of a hydroxamate metalloproteinase inhibitor partially reversed the effects on ICAM-1 and sICAM-1 at 8 h, whereas TIMP-1, -2 or -3 had no effect. MMP-9, but not MMP-2, co-immunoprecipitated with ICAM-1. sICAM-1 was processed distal to Arg441, indicating that MMP-9, docking to ICAM-1, contributes to sICAM-1 shedding and attenuation of the shear stress-induced upregulation of ICAM-1.     

Flow-dependent increase of ICAM-1 on saphenous vein endothelium is sensitive to apamin

The potassium channel blocker tetraethylammonium blocks the flow-induced increase in endothelial ICAM-1. We have investigated the subtype of potassium channel that modulates flow-induced increased expression of ICAM-1 on saphenous vein endothelium. Cultured human saphenous vein endothelial cells (HSVECs) or intact saphenous veins were perfused at fixed low and high flows in a laminar shear chamber or flow rig, respectively, in the presence or absence of potassium channel blockers. Expression of K(+) channels and endothelial ICAM-1 was measured by real-time polymerase chain reaction and/or immunoassays. In HSVECs, the application of 0.8 N/m(2) (8 dyn/cm(2)) shear stress resulted in a two- to fourfold increase in cellular ICAM-1 within 6 h (P < 0.001). In intact vein a similar shear stress, with pulsatile arterial pressure, resulted in a twofold increase in endothelial ICAM-1/CD31 staining area within 1.5 h (P < 0.001). Both increases in ICAM-1 were blocked by inclusion of 100 nM apamin in the vein perfusate, whereas other K(+) channel blockers were less effective. Two subtypes of small conductance Ca(2+)-activated K(+) channel (selectively blocked by apamin) were expressed in HSVECs and vein endothelium (SK3>SK2). Apamin blocked the upregulation of ICAM-1 on saphenous vein endothelium in response to increased flow to implicate small conductance Ca(2+)-activated K(+) channels in shear stress/flow-mediated signaling pathways.     

Enhanced pulmonary allergic responses to Aspergillus in CCR2-/- mice

Allergic responses to Aspergillus species exacerbate asthma and cystic fibrosis. The natural defense against live Aspergillus fumigatus spores or conidia depends on the recruitment and activation of mononuclear and polymorphonuclear leukocytes, events that are dependent on chemotactic cytokines. In this study, we explored the relative contribution of the monocyte chemoattractant protein-1 receptor, CCR2, in the pulmonary response to A. fumigatus conidia. Following sensitization to soluble A. fumigatus Ags, mice lacking CCR2 due to targeted deletion were markedly more susceptible to the injurious effects of an intrapulmonary challenge with live conidia compared with mice that expressed CCR2 or CCR2+/+. CCR2-/- mice exhibited a major defect in the recruitment of polymorphonuclear cells, but these mice also had significantly more eosinophils and lymphocytes in bronchoalveolar lavage samples. CCR2-/- mice also had significant increases in serum levels of total IgE and whole lung levels of IL-5, IL-13, eotaxin, and RANTES compared with CCR2+/+ mice. Airway inflammation, hyper-responsiveness to spasmogens, and subepithelial fibrosis were significantly enhanced in CCR2-/- mice compared with CCR2+/+ mice after the conidia challenge. Thus, these findings demonstrate that CCR2 plays an important role in the immune response against A. fumigatus, thereby limiting the allergic airway inflammatory and remodeling responses to this fungus.     

A 7000‐year history of changing plant trait composition in an Amazonian landscape; the role of humans and climate

Tropical forests are shifting in species and trait composition, but the main underlying causes remain unclear because of the short temporal scales of most studies. Here, we develop a novel approach by linking functional trait data with 7000 years of forest dynamics from a fossil pollen record of Lake Sauce in the Peruvian Amazon. We evaluate how climate and human disturbances affect community trait composition. We found weak relationships between environmental conditions and traits at the taxon level, but strong effects for community‐mean traits. Overall, community‐mean traits were more responsive to human disturbances than to climate change; human‐induced erosion increased the dominance of dense‐wooded, non‐zoochorous species with compound leaves, and human‐induced fire increased the dominance of tall, zoochorous taxa with large seeds and simple leaves. This information can help to enhance our understanding of forest responses to past environmental changes, and improve predictions of future changes in tropical forest composition.     

The duration of lactation in feral coypus (Myocastor coypus)

The frequency of consecutive reproductive stages in a post mortem sample of 423 lactating coypus was used to estimate the mean post partum interval (D_pp) and the mean duration of lactation ( D ₁). The estimates required a number of assumptions but the most important involved the validity of making time specific inferences from an "age" series. Variation statistics could not be calculated using conventional techniques and the jacknife method of estimation was used to obtain variances of the means and 95 % confidence intervals. D_pp was estimated as 21 ± 0–8 weeks. Some observations of retrapped wild animals showed that some animals conceived at an oestrus which occurred within a day or two of parturition. D _l was estimated in four different ways, three of which were quite closely related: these averaged 8–4 ± 10 weeks. But the fourth estimate, which is equally valid, was 70 weeks. A weighted average of the four estimates was 7–7 weeks with 95 % confidence limits of c . ± 10. The average suckling period of five captive females was 10–9 weeks. The most likely interpretation of the 42 % difference between this value and the estimate for wild females is attenuation as a result of a reduced nutrient intake in the feral population. D _L is substantially longer than predicted from an expression relating maternal weight to D _L in other mammals. This may be part of a maternal care strategy that centres on protection of space, and possibly of a food supply for milk production, rather than on defence of the young.     

The SSC: a decade of climate–health research and future directions

This year marks the tenth anniversary of the development of the revised Spatial Synoptic Classification, the “SSC”, by Scott Sheridan. This daily weather-type classification scheme has become one of the key analytical tools implemented in a diverse range of climatological investigations, including analysis of air quality variability, human health, vegetation growth, precipitation and snowfall trends, and broader analyses of historical and future climatic variability and trends. The continued and expanding use of the SSC motivates a review and comparison of the system’s research and geographic foci to date, with the goal of identifying promising areas for future efforts, particularly within the context of human health and climate change. This review also assesses how the SSC has complemented and compares with other current environmental epidemiological studies in weather and health.