Reactive oxygen species and angiotensin II signaling in vascular cells: implications in cardiovascular disease

Diseases such as hypertension, atherosclerosis, hyperlipidemia, and diabetes are associated with vascular functional and structural changes including endothelial dysfunction, altered contractility and vascular remodeling. Cellular events underlying these processes involve changes in vascular smooth muscle cell (VSMC) growth, apoptosis/anoikis, cell migration, inflammation, and fibrosis. Many factors influence cellular changes, of which angiotensin II (Ang II) appears to be amongst the most important. The physiological and pathophysiological actions of Ang II are mediated primarily via the Ang II type 1 receptor. Growing evidence indicates that Ang II induces its pleiotropic vascular effects through NADPH-driven generation of reactive oxygen species (ROS). ROS function as important intracellular and intercellular second messengers to modulate many downstream signaling molecules, such as protein tyrosine phosphatases, protein tyrosine kinases, transcription factors, mitogen-activated protein kinases, and ion channels. Induction of these signaling cascades leads to VSMC growth and migration, regulation of endothelial function, expression of pro-inflammatory mediators, and modification of extracellular matrix. In addition, ROS increase intracellular free Ca2+ concentration ([Ca2+]i), a major determinant of vascular reactivity. ROS influence signaling molecules by altering the intracellular redox state and by oxidative modification of proteins. In physiological conditions, these events play an important role in maintaining vascular function and integrity. Under pathological conditions ROS contribute to vascular dysfunction and remodeling through oxidative damage. The present review focuses on the biology of ROS in Ang II signaling in vascular cells and discusses how oxidative stress contributes to vascular damage in cardiovascular disease.

Study of the physical and physicochemical characteristics of fruits of the licuri palm (Syagrus coronata (Mart.) Becc.) found in the Atlantic Forest of Minas Gerais, Brazil

AbstractThe Atlantic Forest has species of native fruits, consumed fresh and processed, which have an important contribution to food sovereignty of families that consume it. This study examined the physical and physicochemical characteristics, proximate composition, concentration of carotenoids, vitamin C, vitamin E and minerals in the pulp and kernels of fruits of licuri (Syagrus coronata (Mart.) Becc.). Titratable acidity was analyzed by volumetric neutralization, soluble solids by refractometry, proteins by the micro-Kjeldahl method, lipids by gravimetry using soxhlet, dietary fiber by non-enzymatic gravimetry, carotenoids and vitamin C by HPLC-DAD, vitamin E by HPLC-fluorescence, and minerals by ICP-AES. Pulp were a source of Zn (0.95 mg 100–1), a good source of fiber (6.15 g 100–1), excellent source of provitamin A (758.75 RAE 100–1), Cu (0.69 mg 100–1), Fe (3.81 mg 100–1), Mn (3.40 mg 100–1) and Mo (0.06 mg 100–1). The kernel were a source of Fe (3.36 mg 100–1) and excellent source of Mn (6.14 mg 100–1), Cu (0.97 mg 100–1) and Mo (0.07 mg 100–1). The nutritional value and wide availability of licuri fruit make it an important resource for reducing food insecurity and improving nutrition of the rural population and other individuals who have access to it.

Phytoplankton species diversity of 27 lakes and ponds of Costa Rica (Central America)

The literature on species diversity of phytoplankton of tropical lakes is scarce, and for the main part comes from studies of the big lakes in Africa, or deep lakes in South America, leaving a gap in the information about small shallow tropical lakes. In the present work the phytoplankton species composition and diversity of 27 shallow lakes and ponds in Costa Rica (Central America) was studied. The species composition was found to agree with other studies of tropical lakes, with a dominance of Chlorophyta, Cyanophyta, or in some cases Bacillariophyta or Euglenophyta; and a general paucity of Chrysophyta and Cryptophyta. Species richness varied considerably among the lakes, and tended to decrease with an increase in lake elevation. A low evenness in the species abundances was found, with one or more species outnumbering the rest by several orders of magnitude. Individual species abundances and species composition was found to vary with time in Rio Cuarto Lake, a meromictic lake situated in a region with low seasonal change in precipitation. In comparison with the phytoplankton of temperate lakes, the phytoplankton of the tropical lakes studied tended to have a lower evenness of species abundances, although species richness may be similar to temperate figures in some cases. Diversity indices sensitive to changes in the abundance of rare species tend to be higher in the tropical lakes studied; diversity indices sensitive to changes in the numbers of abundant species tend to be similar between the temperate and tropical lakes examined.

Bee Communities in Restored Landfill Sites of Niagara Region

This study examined the impact of habitat restoration on bee communities (Hymenoptera: Apidae) of the Niagara Region, Ontario, Canada. Bee abundance and diversity was studied in three restored landfill sites: the Glenridge Quarry Naturalization Site (GQNS) in St. Catharines, Elm Street Naturalization Site in Port Colborne, and Station Road Naturalization Site in Wainfleet during 2011 and 2012. GQNS represented older sites restored from 2001-2003. Elm and Station sites represented newly restored landfills as of 2011. These sites were compared to control sites at Brock University where bee communities are well established and again to other landfills where no stable habitat was available before restoration. The objective of this study is to investigate the impact of restoration level on bee abundance and diversity in restored landfill sites of the Niagara Region. Based on the increased disturbance hypothesis (InDH) and the intermediate disturbance hypothesis (IDH), I hypothesized that bee abundance and diversity will follow two patterns. First pattern according to InDH suggest that as the disturbance decrease the bee abundance and diversity will increased. Second pattern according to the IDH bee abundance and diversity will be the highest at the intermediate level of disturbance. A total of 7 173 bees were collected using pan traps and flower collections, from May to October 2011 and 2012. Bees were classified to five families, 21 genera and sub-genera, containing at least 78 species. In 2011 bee abundance was not significantly different among restoration levels while in 2012 bee abundance was significant difference among restoration level. According to family there were no significant difference in Halictidae and Apidae abundance among restoration level while Colletidae and Megachilidae abundance were varied among restoration levels. The bee species richness was highest in the newly restored sites followed by restored control sites, and then the control site. The current study demonstrates that habitat restoration results in rapid increases in bee abundance and diversity for newly restored sites, and, further, that it takes only 2-3 years for bee assemblages in newly restored sites to arrive at the same levels of abundance and diversity as in nearby control sites where bee communities are well established.

Dynamique de la biodiversité dans la Serra do Itajaí, Brésil : une approche bioacoustique de la conservation

Le suivi des populations animales et végétales nous a amené à constater une perte importante de la diversité biologique. Les objectifs de la Convention sur la diversité biologique à atteindre pour 2010 sous-tendent la poursuite détaillée de ce suivi à l’échelle mondiale (CBD 2000). Cependant, il est difficile d’avoir une perception d’ensemble de la biodiversité d’un territoire, car les écosystèmes sont des entités dynamiques et évolutives, dans l’espace et dans le temps. Le choix d’un indicateur relevant de l’ensemble des ces caractéristiques devient donc primordial, bien qu’il s’agisse d’une tâche laborieuse. Ce projet propose d’utiliser la bioacoustique comme indicateur environnemental pour faire le suivi des espèces animales en milieu tropical. Afin de faire un suivi à une échelle régionale de la biodiversité, et ce, dans l’un des biomes les plus menacés de la planète, soit celui de la Mata Atlântica brésilienne, ce projet de recherche a comme objectif général de démontrer qu’il est possible d’associer la biophonie (événements sonores), à des événements biologiques (la richesse spécifique animale) en quantifiant des événements sonores (à l’aide des chants produits par les oiseaux, les insectes chanteurs de même que par les anoures) et en tentant de les associer aux fluctuations de la biodiversité. En plus de répondre à cet objectif général, trois objectifs spécifiques ont été définis : 1) comparer la biophonie et l’anthropophonie de milieux soumis à différents niveaux d’anthropisation ou de conservation afin d’évaluer l’impact anthropique sur le milieu, 2) évaluer la variabilité spatiale de la biodiversité, de même que 3) sa variabilité temporelle. Les résultats ont démontré que la biophonie est représentative de la biodiversité d’un milieu, et ce, même dans des conditions de biodiversité maximale puisqu’il existe une très forte relation entre les deux variables. De plus, les résultats révèlent une différence significative dans le ratio anthropophonie/biophonie de milieux soumis à différents niveaux de protection du territoire. La différenciation d’indices de puissance relative (dB/kHz) nous indique également l’importance de la variabilité spatiale et temporelle de la biodiversité, et par conséquent, l’importance de faire le suivi des espèces dans divers milieux et à diverses périodes afin d’obtenir une vision adéquate de la biodiversité régionale.

Effects of plant diversity on bioenergy parameters in grassland biomass

Extensive grassland biomass for bioenergy production has long been subject of scientific research. The possibility of combining nature conservation goals with a profitable management while reducing competition with food production has created a strong interest in this topic. However, the botanical composition will play a key role for solid fuel quality of grassland biomass and will have effects on the combustion process by potentially causing corrosion, emission and slagging. On the other hand, botanical composition will affect anaerobic digestibility and thereby the biogas potential. In this thesis aboveground biomass from the Jena-Experiment plots was harvested in 2008 and 2009 and analysed for the most relevant chemical constituents effecting fuel quality and anaerobic digestibility. Regarding combustion, the following parameters were of main focus: higher heating value (HHV), gross energy yield (GE), ash content, ash softening temperature (AST), K, Ca, Mg, N, Cl and S content. For biogas production the following parameters were investigated: substrate specific methane yield (CH4 sub), area specific methane yield (CH4 area), crude fibre (CF), crude protein (CP), crude lipid (CL) and nitrogen-free extract (NfE). Furthermore, an improvement of the fuel quality was investigated through applying the Integrated generation of solid Fuel and Biogas from Biomass (IFBB) procedure. Through the specific setup of the Jena-Experiment it was possible to outline the changes of these parameters along two diversity gradients: (i) species richness (SR; 1 to 60 species) and (ii) functional group (grasses, legumes, small herbs and tall herbs) presence. This was a novel approach on investigating the bioenergy characteristic of extensive grassland biomass and gave detailed insight in the sward-composition¬ - bioenergy relations such as: (i) the most relevant SR effect was the increase of energy yield for both combustion (annual GE increased by 26% from SR8→16 and by 65% from SR8→60) and anaerobic digestion (annual CH4 area increased by 22% from SR8→16 and by 49% from SR8→60) through a strong interaction of SR with biomass yield; (ii) legumes play a key role for the utilization of grassland biomass for energy production as they increase the energy content of the substrate (HHV and CH4 sub) and the energy yield (GE and CH4 area); (iii) combustion is the conversion technique that will yield the highest energy output but requires an improvement of the solid fuel quality in order to reduce the risk of corrosion, emission and slagging related problems. This was achieved through applying the IFBB-procedure, with reductions in ash (by 23%), N (28%), K (85%), Cl (56%) and S (59%) and equal levels of concentrations along the SR gradient.

Efectes de la invasió de la formiga argentina, Linepithema humile (Mayr), sobre el procés de dispersió de llavors de plantes mediterrànies

La formiga invasora Linepithema humile (Mayr), també coneguda com la formiga argentina, és una espècie present a la península Ibèrica. En aquesta tesi s'ha estudiat com afecta la presència d'aquesta espècie plaga a la comunitat de formigues autòctones y al procés de dispersió de llavors de plantes mediterrànies. L'estudi es va dur a terme en una àrea de sureda i brolla d'estepes i bruc boal situada al nord-est peninsular, prop de la línia de costa mediterrània. Un dels primers y més notables efectes de la invasió a les nostres àrees d'estudi és la dramàtica alteració de la comunitat de formigues, en forma de una reducció de la riquesa específica i de la homogeneïtat d'abundàncies. A més, a les zones envaïdes no hi queda cap espècie de formiga autòctona dispersant de llavors. A causa de la gran abundància d'obreres de la formiga argentina a les zones envaïdes, i del seu elevat ritme d'activitat, aquesta espècie efectua un intens rastreig del sòl, la qual cosa li permet localitzar els recursos en un temps menor que les formigues autòctones de les zones no envaïdes. No obstant, la obertura mandibular de la comunitat de formigues esdevé molt disminuïda a les zones envaïdes a causa de la desaparició de les espècies autòctones, la majoria d'elles de mida més grossa que la formiga argentina, la qual cosa podria limitar la capacitat de manipulació de l'entorn que té la comunitat de formigues a les zones envaïdes, i podria explicar la falta de reemplaçament d'alguns dels rols que duien a terme les espècies de formigues autòctones abans de la invasió. La formiga argentina es mostra atreta per les llavors de les nou espècies vegetals estudiades (dues euforbiàcies: Euphorbia biumbellata i E. characias; dues compostes: Cirsium vulgare i Galactites tomentosa; i cinc papilionàcies: Genista linifolia, G. monspessulana, G. triflora, Sarothamnus arboreus i Ulex parviflorus), arribant a transportar i fins i tot introduir al niu algunes llavors, però amb probabilitats inferiors a les realitzades per les formigues autòctones de les zones no envaïdes. No obstant, el seu comportament davant les nou espècies de llavors és variable, de manera que sembla que el seu efecte sobre la dispersió de llavors podria ser diferent per a cada espècie vegetal. L'alteració del procés de dispersió no sembla alterar l'èxit reproductiu d'una espècie concreta, Euphorbia characias, a les zones envaïdes; ni el seu reclutament, ni la distribució espacial, ni la supervivència de les plàntules són significativament diferents a les zones envaïdes que a les no envaïdes. La desaparició de les espècies de formigues granívores de les zones envaïdes pot afectar la dinàmica de les llavors de plantes no mirmecòcores. Així, les llavors de tres papilionàcies (Calicotome spinosa, Psoralea bituminosa i Spartium junceum) resulten amb un menor nivell de transports (i probablement menor depredació) a les zones envaïdes per la formiga argentina.

Ovenbird (Seiurus aurocapilla) Territory Placement Near Seismic Lines is Influenced by Forest Regeneration and Conspecific Density

The boreal forest of western Canada is being dissected by seismic lines used for oil and gas exploration. The vast amount of edge being created is leading to concerns that core habitat will be reduced for forest interior species for extended periods of time. The Ovenbird (Seiurus aurocapilla) is a boreal songbird known to be sensitive to newly created seismic lines because it does not include newly cut lines within its territory. We examined multiple hypotheses to explain potential mechanisms causing this behavior by mapping Ovenbird territories near lines with varying states of vegetation regeneration. The best model to explain line exclusion behavior included the number of neighboring conspecifics, the amount of bare ground, leaf-litter depth, and canopy closure. Ovenbirds exclude recently cut seismic lines from their territories because of lack of protective cover (lower tree and shrub cover) and because of reduced food resources due to large areas of bare ground. Food reduction and perceived predation risk effects seem to be mitigated once leaf litter (depth and extent of cover) and woody vegetation cover are restored to forest interior levels. However, as conspecific density increases, lines are more likely to be used as landmarks to demarcate territorial boundaries, even when woody vegetation cover and leaf litter are restored. This behavior can reduce territory density near seismic lines by changing the spatial distribution of territories. Landmark effects are longer lasting than the effects from reduced food or perceived predation risk because canopy height and tree density take >40 years to recover to forest interior levels. Mitigation of seismic line impacts on Ovenbirds should focus on restoring forest cover as quickly as possible after line cutting.

National and sub-national assessments of soil organic carbon stocks and changes: The GEFSOC modelling system

Soil organic carbon (SOC) plays a vital role in ecosystem function, determining soil fertility, water holding capacity and susceptibility to land degradation. In addition, SOC is related to atmospheric CO, levels with soils having the potential for C release or sequestration, depending on land use, land management and climate. The United Nations Convention on Climate Change and its Kyoto Protocol, and other United Nations Conventions to Combat Desertification and on Biodiversity all recognize the importance of SOC and point to the need for quantification of SOC stocks and changes. An understanding of SOC stocks and changes at the national and regional scale is necessary to further our understanding of the global C cycle, to assess the responses of terrestrial ecosystems to climate change and to aid policy makers in making land use/management decisions. Several studies have considered SOC stocks at the plot scale, but these are site specific and of limited value in making inferences about larger areas. Some studies have used empirical methods to estimate SOC stocks and changes at the regional scale, but such studies are limited in their ability to project future changes, and most have been carried out using temperate data sets. The computational method outlined by the Intergovernmental Panel on Climate Change (IPCC) has been used to estimate SOC stock changes at the regional scale in several studies, including a recent study considering five contrasting eco regions. This 'one step' approach fails to account for the dynamic manner in which SOC changes are likely to occur following changes in land use and land management. A dynamic modelling approach allows estimates to be made in a manner that accounts for the underlying processes leading to SOC change. Ecosystem models, designed for site scale applications can be linked to spatial databases, giving spatially explicit results that allow geographic areas of change in SOC stocks to be identified. Some studies have used variations on this approach to estimate SOC stock changes at the sub-national and national scale for areas of the USA and Europe and at the watershed scale for areas of Mexico and Cuba. However, a need remained for a national and regional scale, spatially explicit system that is generically applicable and can be applied to as wide a range of soil types, climates and land uses as possible. The Global Environment Facility Soil Organic Carbon (GEFSOC) Modelling System was developed in response to this need. The GEFSOC system allows estimates of SOC stocks and changes to be made for diverse conditions, providing essential information for countries wishing to take part in an emerging C market, and bringing us closer to an understanding of the future role of soils in the global C cycle. (C) 2007 Elsevier B.V. All rights reserved.

Mediterranean ecosystems: problems and tools for conservation

Mediterranean ecosystems rival tropical ecosystems in terms of plant biodiversity. The Mediterranean Basin (MB) itself hosts 25 000 plant species, half of which are endemic. This rich biodiversity and the complex biogeographical and political issues make conservation a difficult task in the region. Species, habitat, ecosystem and landscape approaches have been used to identify conservation targets at various scales: ie, European, national, regional and local. Conservation decisions require adequate information at the species, community and habitat level. Nevertheless and despite recent improvements/efforts, this information is still incomplete, fragmented and varies from one country to another. This paper reviews the biogeographic data, the problems arising from current conservation efforts and methods for the conservation assessment and prioritization using GIS. GIS has an important role to play for managing spatial and attribute information on the ecosystems of the MB and to facilitate interactions with existing databases. Where limited information is available it can be used for prediction when directly or indirectly linked to externally built models. As well as being a predictive tool today GIS incorporate spatial techniques which can improve the level of information such as fuzzy logic, geostatistics, or provide insight about landscape changes such as 3D visualization. Where there are limited resources it can assist with identifying sites of conservation priority or the resolution of environmental conflicts (scenario building). Although not a panacea, GIS is an invaluable tool for improving the understanding of Mediterranean ecosystems and their dynamics and for practical management in a region that is under increasing pressure from human impact.

Dispersal capacity and diet breadth modify the response of wild bees to habitat loss

Habitat loss poses a major threat to biodiversity, and species-specific extinction risks are inextricably linked to life-history characteristics. This relationship is still poorly documented for many functionally important taxa, and at larger continental scales. With data from five replicated field studies from three countries, we examined how species richness of wild bees varies with habitat patch size. We hypothesized that the form of this relationship is affected by body size, degree of host plant specialization and sociality. Across all species, we found a positive species–area slope (z ¼ 0.19), and species traits modified this relationship. Large-bodied generalists had a lower z value than small generalists. Contrary to predictions, small specialists had similar or slightly lower z value compared with large specialists, and small generalists also tended to be more strongly affected by habitat loss as compared with small specialists. Social bees were negatively affected by habitat loss (z ¼ 0.11) irrespective of body size. We conclude that habitat loss leads to clear shifts in the species composition of wild bee communities.

Organic farming in isolated landscapes does not benefit flower-visiting insects and pollination

Organic farming has often been found to provide benefits for biodiversity, but the benefits can depend on the species considered and characteristics of the surrounding landscape. In an intensively farmed area of Northeast Italy we investigated whether isolated organic farms, in a conventionally farmed landscape, provided local benefits for insect pollinators and pollination services. We quantified the relative effects of local management (i.e. the farm system), landscape management (proportion of surrounding uncultivated land) and interactions between them. We compared six organic and six conventional vine fields. The proportion of surrounding uncultivated land was calculated for each site at radii of 200, 500, 1000 and 2000 m. The organic fields did not differ from the conventional in their floral resources or proportion of surrounding uncultivated land. Data were collected on pollinator abundance and species richness, visitation rates to, and pollination of experimental potted plants. None of these factors were significantly affected by the farming system. The abundance of visits to the potted plants in the conventional fields tended to be negatively affected by the proportion of surrounding uncultivated land. The proportion fruit set, weight of seeds per plant and seed weight in conventional and organic fields were all negatively affected by the proportion of surrounding uncultivated land. In vine fields the impact of the surrounding landscape was stronger than the local management. Enhancement of biodiversity through organic farming should not be assumed to be ubiquitous, as potential benefits may be offset by the crop type, organicmanagement practices and the specific habitat requirements in the surrounding landscape.

Hay strewing, brush harvesting of seed and soil disturbance as tools for the enhancement of botanical diversity in grasslands

Since the middle of the last century agricultural intensification within Europe has led to a drastic decline in the extent of botanically diverse grasslands. Whilst measures to enhance the diversity of agriculturally-improved grasslands are in place, success has often been limited. One of the primary factors limiting success is the paucity of sources of propagules of desirable species in the surrounding landscape. The restoration of two contrasting grassland types lowland hay meadow and chalk grassland) was examined using a replicated block experiment to assess the effectiveness of two methods of seed application (hay strewing and brush harvesting) and two methods of pre-treatment disturbance (power harrowing and turf stripping). The resulting changes in botanical composition were monitored for 4 years. Seed addition by both methods resulted in significant temporal trends in plant species composition and increases in plant species richness, which were further enhanced by disturbance. Power harrowing increased the effectiveness of the seed addition treatments at the lowland hay meadow site. At the chalk grassland site a more severe disturbance created by turf stripping was used and shown to be preferable. Whilst both hay strewing and brush harvesting increased plant species richness, hay strewing was more effective at creating a sward similar to that of the donor site. Soil disturbance and seed application rate at the recipient site and timing of the hay cut at the donor site are all factors to be considered prior to the commencement of restoration management. (c) 2006 Elsevier Ltd. All rights reserved.

Vascular plant diversity and climate change in the alpine zone of the Lefka Ori, Crete

The aim of this study is to analyse the vascular flora and the local climate along an altitudinal gradient in the Lefka Ori massif Crete and to evaluate the potential effects of climate change on the plant diversity of the sub-alpine and alpine zones. It provides a quantitative/qualitative analysis of vegetation-environment relationships for four summits along an altitude gradient on the Lefka Ori massif Crete (1664-2339 m). The GLORIA multi-summit approach was used to provide vegetation and floristic data together with temperature records for every summit. Species richness and species turnover was calculated together with floristic similarity between the summits. 70 species were recorded, 20 of which were endemic, belonging to 23 different families. Cretan endemics dominate at these high altitudes. Species richness and turnover decreased with altitude. The two highest summits showed greater floristic similarity. Only 20% of the total flora recorded reaches the highest summit while 10% is common among summits. Overall there was a 4.96 degrees C decrease in temperature along the 675 m gradient. Given a scenario of temperature increase the ecotone between the sub-alpine and alpine zone would be likely to have the greatest species turnover. Southern exposures are likely to be invaded first by thermophilous species while northern exposures are likely to be more resistant to changes. Species distribution shifts will also depend on habitat availability. Many, already threatened, local endemic species will be affected first.