Are Podoplanin and Ezrin Involved in the Invasion Process of the Ameloblastomas?

The association between podoplanin and ezrin in the process of odontogenic tumors invasion has been suggested, but was not studied yet. Our purpose was to investigate the relationship between podoplanin and ezrin expressions in the odontogenic epithelium of ameloblastomas. Forty-seven ameloblastomas were analyzed by immunohistochemistry using anti-podoplanin and anti-ezrin antibodies. The expressions of both proteins were evaluated using a score method and the comparison and association between these proteins were verified, respectively, by Wilcoxon Signed-Rank test and by Spearman’s rank correlation coefficient, using a statistical significance level of 0.05. The majority of tumors (87.2%) exhibited strong membranous expression of podoplanin in the peripheral cells. Cytoplasmic expression of ezrin in the peripheral cells of ameloblastomas was stronger than its membranous expression. No statistically significant correlation was observed between podoplanin and ezrin. However, there was statistically significant difference between membranous podoplanin and membranous ezrin expressions, between cytoplasmic podoplanin and membranous ezrin expressions, and between cytoplasmic podoplanin and cytoplasmic ezrin expressions. There was no statistical difference between membranous podoplanin and cytoplasmic ezrin expressions. These results suggest a synergistic role of both proteins in the process of invasion of ameloblastomas.Key words: Odontogenic tumor, ameloblastoma, podoplanin, ezrin, adhesion molecule     

Are there age-related differences in the song repertoire size of Eurasian blackbirds?

Most oscine bird species possess a repertoire of different song patterns, and repertoire size is thought to signal aspects of male quality. As age is assumed to be related to male quality in terms of experience and/or viability, repertoire size may be expected to reflect male age. Here, we investigated the relationship between repertoire size and age (yearlings or older) in Eurasian blackbirds, Turdus merula, a species with a large repertoire delivered in a highly variable manner. We found that older males tended to have larger repertoires than yearlings though the two age groups overlapped considerably. Thus, compared to other species with large repertoires, age-related differences in repertoire size seem rather small in male Eurasian blackbirds. We also compared repertoires of three individuals in two successive years (as yearlings and in the year following) and found a large element turnover. Our investigation revealed that this turnover was almost complete in the quiet terminating twitter part of the song. Such turnover may allow a young bird to adjust his repertoire to his neighbours?? repertoires, which could be useful for song matching interactions.     

Are there Atlantic salmon in the River Tambre?

Genetic variability and assignment analyses demonstrate that the 60 returning adult salmon to the Tambre River in 2005 were not the product of an incipient wild population, but the result of straying from a neighbouring river.     

Are the Costs of Site Unfamiliarity Compensated With Vigilance? A Field Test in Eurasian Siskins

Determination of fitness differentials between individuals adopting different migratory and dispersal strategies is basic to understand the evolution of migration. In the Eurasian siskin Carduelis spinus, both resident and transient birds forage within the same wintering area, providing the rare opportunity to compare their foraging behaviour in the same area and habitat. The aim of this study was to test the predictions associated to the different hypothesized costs of transience by studying the vigilance and foraging behaviour of wild wintering siskins foraging at three bird tables with different predation risk and interference competition levels. Transient siskins showed longer scan durations than residents, either because of site unfamiliarity or subordination (i.e. prior‐occupancy effect). However, residents and transients did not differ in aggression rates, contrary to the dear‐enemy effect. Transient siskins did not show a higher allocation of time to vigilance, contrary to the hypothesis of compensation vigilance to reduce predation risk by dispersing animals. Moreover, transients increased pecking rate with increasing predation risk, showed lower scan rates, longer foraging bouts and, in males, presented marginally higher proportions far from cover. Altogether these results strongly support the hypothesis that transients incur a predation cost due to a less efficient vigilance and foraging system.     

Reconciling Conservation and Development: Are Landscapes the Answer?

The landscape approach is being used for initiatives that have the dual objectives of conserving biodiversity and alleviating poverty. However, working at such landscape scales greatly expands the level of ambition of conservation organizations and requires them to use skills that differ from those that they have traditionally deployed. Influencing landscape change requires major commitments for long periods of time and since there is still little evidence for the success of such approaches they should be used cautiously. Landscape programmes must be based on a comprehensive understanding of landscape dynamics and of the underlying drivers of social, economic and ecological change. Just as in any other investment in conservation it is important to set objectives in clear and measurable terms. Landscape approaches should therefore complement and not replace more conventional biodiversity conservation measures. They should be guided by scenarios agreed by concerned stakeholders, should be constructivist and in most cases their success will require major changes in the behavior of local people.     

Reinvestment – the Cause of the Yips?

The yips is a multi-etiological phenomenon consisting of involuntary movements during the execution of a skill (e.g., a golf putt). Reinvestment, the conscious control of a movement that detrimentally affects automated movements, is thought to be a potential mechanism leading to the yips. Preventing yips-affected golfers from consciously controlling their movement, therefore, should be beneficial. The aim of the study was to be the first to empirically test in a laboratory whether reinvestment causes the yips and to explore if the tendency to reinvest can explain yips behavior. Nineteen yips-affected golfers participated in a lab experiment. They putted with the dominant arm in a skill-focus and an extraneous condition, in which they had to perform different dual tasks designed either to direct their focus on their own skill or to distract them from it. The tendency to reinvest was estimated via the Movement-Specific Reinvestment Scale. Yips behavior was assessed by putting performance and movement variability. Although the dual-task performance showed that the attentional manipulation worked, the tendency to reinvest did not predict the behavior of the yips-affected golfers in either putting condition. The yips-affected golfers also showed no difference in yips behavior between the skill-focus and the extraneous condition. In other words, the attentional manipulation did not change yips behavior. The data do not support the assumption that there is a link between the yips and reinvestment, likely because of the multi-etiological nature of the yips. Other psychological or neurological mechanisms such as conditioned reactions may better explain the yips and should be investigated.     

Are High-Severity Fires Burning at Much Higher Rates Recently than Historically in Dry-Forest Landscapes of the Western USA?

Dry forests at low elevations in temperate-zone mountains are commonly hypothesized to be at risk of exceptional rates of severe fire from climatic change and land-use effects. Their setting is fire-prone, they have been altered by land-uses, and fire severity may be increasing. However, where fires were excluded, increased fire could also be hypothesized as restorative of historical fire. These competing hypotheses are not well tested, as reference data prior to widespread land-use expansion were insufficient. Moreover, fire-climate projections were lacking for these forests. Here, I used new reference data and records of high-severity fire from 1984–2012 across all dry forests (25.5 million ha) of the western USA to test these hypotheses. I also approximated projected effects of climatic change on high-severity fire in dry forests by applying existing projections. This analysis showed the rate of recent high-severity fire in dry forests is within the range of historical rates, or is too low, overall across dry forests and individually in 42 of 43 analysis regions. Significant upward trends were lacking overall from 1984–2012 for area burned and fraction burned at high severity. Upward trends in area burned at high severity were found in only 4 of 43 analysis regions. Projections for A.D. 2046–2065 showed high-severity fire would generally be still operating at, or have been restored to historical rates, although high projections suggest high-severity fire rotations that are too short could ensue in 6 of 43 regions. Programs to generally reduce fire severity in dry forests are not supported and have significant adverse ecological impacts, including reducing habitat for native species dependent on early-successional burned patches and decreasing landscape heterogeneity that confers resilience to climatic change. Some adverse ecological effects of high-severity fires are concerns. Managers and communities can improve our ability to live with high-severity fire in dry forests.     

The role of outcrops in the diversity of Patagonian vegetation: Relicts of glacial palaeofloras?

Outcrops around the world enhance biodiversity as they provide heterogeneous environments and varied habitats for species with different requirements than those living in the surroundings, and in this way they increase alpha and beta diversity. We studied the floristic composition of the vegetation of rock outcrops in northwestern Patagonia, Argentina, and compared them to the surrounding matrix of shrubland and steppe. For this we sampled 50 outcrops and 50 matrix plots close to them, identified all the species present, and analyzed their floristic composition with Detrended Correspondence Analysis (DCA). We also analyzed the floras of the north and south faces of the outcrops. The resulting ordinations were related to geographic gradients of the region. The proportions of alien to native species, different life forms, and phylogenetic groups of the outcrop floras were compared to the matrix with G-tests. Our results showed similar dominant families, life form proportions and percentage of alien species in the outcrops and the surrounding matrix. However, species composition of the outcrops was markedly different. North Patagonian outcrops present several taxa not found in the matrix, especially in their southern, less insolated walls. The previously recorded distribution of most of these exclusive species is found in colder areas further south. Thus, we hypothesize that outcrops could be acting as relicts of cold-adapted glacial paleofloras that were probably more extended during glacial times and retreated south after the last glacial maximum.     

Are Protected Areas Required to Maintain Functional Diversity in Human-Modified Landscapes?

The conversion of forest to agriculture across the world’s tropics, and the limited space for protected areas, has increased the need to identify effective conservation strategies in human-modified landscapes. Isolated trees are believed to conserve elements of ecological structure, providing micro-sites for conservation in matrix landscapes, and facilitating seed dispersal and forest restoration. Here we investigate the role of isolated Ficus trees, which are of critical importance to tropical forest ecosystems, in conserving frugivore composition and function in a human-modified landscape in Assam, India. We surveyed the frugivorous birds feeding at 122 isolated Ficus trees, 33 fruit trees, and 31 other large trees across a range of 32 km from the nearest intact forest. We found that Ficus trees attracted richer and more abundant assemblages of frugivores than the other tree categories. However, incidence function estimates revealed that forest specialist species decreased dramatically within the first kilometre of the forest edge. Despite this, species richness and functional diversity remained consistent across the human-modified landscape, as habitat generalists replaced forest-dependent frugivores, and accounted for most of the ecological function found in Ficus trees near the forest edge. We recommend that isolated Ficus trees are awarded greater conservation status, and suggest that their conservation can support ecologically functional networks of frugivorous bird communities.     

Widespread and Enzyme-independent N?-Acetylation and N?-Succinylation of Proteins in the Chemical Conditions of the Mitochondrial Matrix

Alterations in mitochondrial protein acetylation are implicated in the pathophysiology of diabetes, the metabolic syndrome, mitochondrial disorders, and cancer. However, a viable mechanism responsible for the widespread acetylation in mitochondria remains unknown. Here, we demonstrate that the physiologic pH and acyl-CoA concentrations of the mitochondrial matrix are sufficient to cause dose- and time-dependent, but enzyme-independent acetylation and succinylation of mitochondrial and nonmitochondrial proteins in vitro. These data suggest that protein acylation in mitochondria may be a chemical event facilitated by the alkaline pH and high concentrations of reactive acyl-CoAs present in the mitochondrial matrix. Although these results do not exclude the possibility of enzyme-mediated protein acylation in mitochondria, they demonstrate that such a mechanism may not be required in its unique chemical environment. These findings may have implications for the evolutionary roles that the mitochondria-localized SIRT3 deacetylase and SIRT5 desuccinylase have in the maintenance of metabolic health.     

Are we missing half of the viruses in the ocean?

Viruses are abundant in the ocean and a major driving force in plankton ecology and evolution. It has been assumed that most of the viruses in seawater contain DNA and infect bacteria, but RNA-containing viruses in the ocean, which almost exclusively infect eukaryotes, have never been quantified. We compared the total mass of RNA and DNA in the viral fraction harvested from seawater and using data on the mass of nucleic acid per RNA- or DNA-containing virion, estimated the abundances of each. Our data suggest that the abundance of RNA viruses rivaled or exceeded that of DNA viruses in samples of coastal seawater. The dominant RNA viruses in the samples were marine picorna-like viruses, which have small genomes and are at or below the detection limit of common fluorescence-based counting methods. If our results are typical, this means that counts of viruses and the rate measurements that depend on them, such as viral production, are significantly underestimated by current practices. As these RNA viruses infect eukaryotes, our data imply that protists contribute more to marine viral dynamics than one might expect based on their relatively low abundance. This conclusion is a departure from the prevailing view of viruses in the ocean, but is consistent with earlier theoretical predictions.     

What Is the Primary Cause of Individual Differences in Contrast Sensitivity?

One of the primary objectives of early visual processing is the detection of luminance variations, often termed image contrast. Normal observers can differ in this ability by at least a factor of 4, yet this variation is typically overlooked, and has never been convincingly explained. This study uses two techniques to investigate the main source of individual variations in contrast sensitivity. First, a noise masking experiment assessed whether differences were due to the observer’s internal noise, or the efficiency with which they extracted information from the stimulus. Second, contrast discrimination functions from 18 previous studies were compared (pairwise, within studies) using a computational model to determine whether differences were due to internal noise or the low level gain properties of contrast transduction. Taken together, the evidence points to differences in contrast gain as being responsible for the majority of individual variation across the normal population. This result is compared with related findings in attention and amblyopia.     

Are zebra mussels restricted by toxicant levels in the River Meuse? a review

This paper questions if chemical barriers prevent the occurrence of benthic invertebrates in the river Meuse. To this purpose an ecotoxicological analysis is presented, using published observations on the zebra musselDreissena polymorpha, a tolerant species that maintains populations in the river. Zebra mussels collected or exposed at the Belgian-Dutch border contained high levels of several groups of toxicants, and mixture toxicity is likely to occur. A recently developed bio-assay, using the filtration rate of the zebra mussel, demonstrated strong inhibitory effects of water from the river Meuse. To determine which (combination of) toxicants cause such effects, laboratory experiments with toxicant mixtures were carried out. It was demonstrated that in a mixture of five metals (Cu, Zn, Ni, Cd, Pb) the metals contributed to the toxicity of the mixture below the No Observed Effect Concentrations (NOEC) for these metals when tested individually. The average concentration of Cu, Zn and possibly Pb in Meuse water exceed the NOEC values for filtration rate. Thus, it seems likely that joint effects of different (groups of) toxicants in the river Meuse cause the overall toxicity of the water for the zebra mussel, explaining the marginal populations at the test site, while other river species are absent there. It is suggested that toxicants in the river Meuse restrict the recolonisation of the river by invertebrate species more sensitive than the zebra mussel. This will be studied using invertebrates of different sensitivities (molluscs, arthropods), enabling the assessment of toxicity at different stages of water quality improvement of the river Meuse.     

Tabula rasa in the Patagonian Channels? The phylogeography of Oreobolus obtusangulus (Cyperaceae)

The extent of the Pleistocene glaciations in the Patagonian Channel region (southwesternmost South America) and their impact on the vegetation there are largely unknown. Whether the regional flora was wiped out completely (tabula rasa) or survived in ice‐free pockets (in situ survival) is still an open question. The molecular imprint of either scenario should still be visible in extant populations. Therefore, DNA sequence data of Oreobolus obtusangulus Gaudich. (Cyperaceae) were analysed. This species is an abundant constituent of Patagonian cushion peat bogs, one of the Patagonian Channel region's major vegetation types. Three hundred and eighty‐four individuals from 48 populations were sequenced for two chloroplast (ycf3‐psaA and trnQ^UUG‐psbK intergenic spacers) and 14 nuclear loci containing simple sequence repeats (SSRs; microsatellites). Phylogenetic reconstructions and the geographic distribution of genetic diversity revealed that the species was split into three main lineages whose general distributions comprise three separate major regions, that is, south‐central Chile, Fuego‐Patagonia and the East Patagonian Andes, which probably constitute glacial refugia. Postglacial migration fronts formed a suture zone with high levels of genetic diversity in the Northwest Patagonian Andes, where remnants of a supposedly ancestral lineage were also found to be locally restricted to a single population (Huinay). The heavily glaciated Patagonian Channels were likely recolonized from the northwest, and partly from the south. Although the westernmost Patagonian Channel population (Estero Bachem) harboured private SSR alleles (singletons) and showed slightly elevated genetic diversity, it remained unclear whether this population actually survived in situ. This study helps fill a major gap in reconstructing the Pleistocene vegetation history of West and Andean Patagonia.     

Are carotenoids the blue-light photoreceptor in the photoinduction of protoperithecia in Neurospora crassa?

A triple albino mutant of Neurospora crassa with a measured content of carotenoids absorbing at 470 nm less than 0.5% of that of the wild type (calculated value less than 8·10^-4%) had the same threshold for photoinduction of protoperithecia as the wild type when illuminated with monochromatic light at 471 nm. This is strong evidence against the hypothesis that the bulk of carotenoids are the blue-light photoreceptor for this phenomenon. However, it is impossible to exclude traces of carotenoids acting as the photoreceptor at less than 3·10^-12 M in a very efficient sensory transduction chain.Abbreviations A absorbance - al albino mutant - WT wild type