Remote estimation of carbon dioxide uptake by a Mediterranean forest

The estimation of the carbon balance in ecosystems, regions, and the biosphere is currently one of the main concerns in the study of the ecology of global change. Current remote sensing methodologies for estimating gross primary productivity are not satisfactory because they rely too heavily on (i) the availability of climatic data, (ii) the definition of land‐use cover, and (iii) the assumptions of the effects of these two factors on the radiation‐use efficiency of vegetation (RUE). A new methodology is urgently needed that will actually assess RUE and overcome the problems associated with the capture of fluctuations in carbon absorption in space and over time. Remote sensing techniques such as the widely used reflectance vegetation indices (e.g. NDVI, EVI) allow green plant biomass and therefore plant photosynthetic capacity to be assessed. However, there are vegetation types, such as the Mediterranean forests, with a very low seasonality of these vegetation indices and a high seasonality of carbon uptake. In these cases it is important to detect how much of this capacity is actually realized, which is a much more challenging goal. The photochemical reflectance index (PRI) derived from freely available satellite information (MODIS sensor) presented for a 5‐year analysis for a Mediterranean forest a positive relationship with the RUE. Thus, we show that it is possible to estimate RUE and GPP in real time and therefore actual carbon uptake of Mediterranean forests at ecosystem level using the PRI. This conceptual and technological advancement would avoid the need to rely on the sometimes unreliable maximum RUE.     

Fhit interaction with ferredoxin reductase triggers generation of reactive oxygen species and apoptosis of cancer cells

Fhit protein is lost in most cancers, its restoration suppresses tumorigenicity, and virus-mediated FHIT gene therapy induces apoptosis and suppresses tumors in preclinical models. We have used protein cross-linking and proteomics methods to characterize a Fhit protein complex involved in triggering Fhit-mediated apoptosis. The complex includes Hsp60 and Hsp10 that mediate Fhit stability and may affect import into mitochondria, where it interacts with ferredoxin reductase, responsible for transferring electrons from NADPH to cytochrome P450 via ferredoxin. Viral-mediated Fhit restoration increases production of intracellular reactive oxygen species, followed by increased apoptosis of lung cancer cells under oxidative stress conditions; conversely, Fhit-negative cells escape apoptosis, carrying serious oxidative DNA damage that may contribute to an increased mutation rate. Characterization of Fhit interacting proteins has identified direct effectors of the Fhit-mediated apoptotic pathway that is lost in most cancers through loss of Fhit.     

A New Cell-Selective Three-Dimensional Microincubator Based on Silicon Photonic Crystals

In this work, we show that vertical, high aspect-ratio (HAR) photonic crystals (PhCs), consisting of periodic arrays of 5 µm wide gaps with depth of 50 µm separated by 3 µm thick silicon walls, fabricated by electrochemical micromachining, can be used as three-dimensional microincubators, allowing cell lines to be selectively grown into the gaps. Silicon micromachined dice incorporating regions with different surface profiles, namely flat silicon and deeply etched PhC, were used as microincubators for culturing adherent cell lines with different morphology and adhesion properties. We extensively investigated and compared the proliferative behavior on HAR PhCs of eight human cell models, with different origins, such as the epithelial (SW613-B3; HeLa; SW480; HCT116; HT29) and the mesenchymal (MRC-5V1; CF; HT1080). We also verified the contribution of cell sedimentation into the silicon gaps. Fluorescence microscopy analysis highlights that only cell lines that exhibit, in the tested culture condition, the behavior typical of the mesenchymal phenotype are able to penetrate into the gaps of the PhC, extending their body deeply in the narrow gaps between adjacent silicon walls, and to grow adherent to the vertical surfaces of silicon. Results reported in this work, confirmed in various experiments, strongly support our statement that such three-dimensional microstructures have selection capabilities with regard to the cell lines that can actively populate the narrow gaps. Cells with a mesenchymal phenotype could be exploited in the next future as bioreceptors, in combination with HAR PhC optical transducers, e.g., for label-free optical detection of cellular activities involving changes in cell adhesion and/or morphology (e.g., apoptosis) in a three-dimensional microenvironment.     

A spectacular new species of Nepenthes L. (Nepenthaceae) pitcher plant from central Palawan,Philippines

A new species of Nepenthes L., N. attenboroughii (Nepenthaceae), from Palawan Island in the Philippines, is described and illustrated. It is restricted to rocky, ultramafic soils that comprise the summit region of Mount Victoria, Municipality of Narra, where it occurs in isolation from other members of the genus. On the basis of the morphological features, this new taxon appears to be related to both N. mira Jebb & Cheek of Palawan and N. rajah Hook.f. of Borneo. Its substantial size places it among the largest of known pitcher plants. The diagnostic morphological characters are discussed and an updated key is provided for a revised complex of Nepenthes species from the Palawan and North Borneo phytogeographical region. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 195–202.     

Spread and impact of introduced conifers in South America: Lessons from other southern hemisphere regions

The history of conifers introduced earlier elsewhere in the southern hemisphere suggests that recent invasions in Argentina, Brazil, Chile and Uruguay are likely to increase in number and size. In South Africa, New Zealand and Australia, early ornamental introductions and small forestry plantations did not lead to large‐scale invasions, while subsequent large plantations were followed with a lag of about 20–30 years by troublesome invasions. Large‐scale conifer plantation forestry in South America began about 50–80 years later than in South Africa, Australia and New Zealand, while reports of invasions in South America lagged behind those in the latter nations by a century. Impacts of invading non‐native conifers outside South America are varied and include replacement of grassland and shrubland by conifer forest, alteration of fire and hydrological regimes, modification of soil nutrients, and changes in aboveground and belowground biotic communities. Several of these effects have already been detected in various parts of South America undergoing conifer invasion. The sheer amount of area planted in conifers is already very large in Chile and growing rapidly in Argentina and Brazil. This mass of reproductive trees, in turn, produces an enormous propagule pressure that may accelerate ongoing invasions and spark new ones at an increasing rate. Regulations to control conifer invasions, including measures to mitigate spread, were belatedly implemented in New Zealand and South Africa, as well as in certain Australian states, inspired by observations on invasions in those nations. Regulations in South America are weaker and piecemeal, but the existing research base on conifer invasions elsewhere could be useful in fashioning effective regulations in South America. Pressure from foreign customers in South Africa has led most companies there to seek certification through the Forestry Stewardship Council; a similar programme operates in Australia. Such an approach may be promising in South America.     

MicroRNAs: fundamental facts and involvement in human diseases

MicroRNAs (miRNAs) are a group of small noncoding RNAs that have been identified in a variety of organisms. These small, 18-22-nucleotide (nt) RNAs are transcribed as parts of longer molecules called pri-miRNAs, which are processed in the nucleus into hairpin RNAs of 70-100 nt, called pre-miRNAs, by the double-stranded RNA (dsRNA)-specific ribonuclease Drosha. The function of most miRNAs is not known, but for a few members the participation in essential biological processes for the eukaryotic cell is proven. In this review, we summarize how miRNAs were discovered, their biological functions, and importance in animal development, highlighting their function in proliferation, apoptosis, and cell differentiation. Furthermore, we discuss the deregulation of miRNAs in human diseases and their involvement in tumorigenesis.     

Deconstructing Ixodes ricinus: a partial matrix model allowing mapping of tick development,mortality and activity rates

A stage‐structured Leslie matrix model of a partial, discrete population of Ixodes ricinus (Linnaeus) (Ixodida: Ixodidae) ticks was developed to elucidate the impact of climate trends on the distribution and phenology of this species in the western Palaearctic. The model calculates development and mortality rates for each instar and evaluates recruitment rates based on the development of the tick population. The model captures the changes in development and mortality rates, providing a coherent index of performance correlated with the tick's geographic range. Maximum development rates are recorded for latitudes south of 36 °N and are spatially correlated with sites of maximum temperature, highest saturation deficit and highest mortality. The maximum available developmental time (the total annual time during which temperature allows development) for I. ricinus in the western Palaearctic is < 45% of the total year. North of 60 °N, available developmental time decreases sharply to only 15% of the year. The latitudinal boundary at which survival rates sharply drop is 43–46 °N, clearly delimiting the classically recognized extent of the main tick populations. The pattern of activity for larval–nymphal synchrony shows a clear west–east pattern. The model demonstrates the impact of climate according to tick stage and geographic location, and provides a practical framework for testing how the tick's lifecycle is affected by climate change.