A novel transmembrane MSP-containing protein that plays a role in right ventricle development

We have identified and characterized a gene, Mospd3 on mouse chromosome 5 using gene trapping in ES cells. MOSPD3 is part of a family of proteins, including MOSPD1, which is defined by the presence of a major sperm protein (MSP) domain and two transmembrane domains. Interestingly Mospd3 is mammalian specific and highly conserved between mouse and man. Insertion of the gene trap vector at the Mospd3 locus is mutagenic and breeding to homozygosity results in a characteristic right ventricle defect and neonatal lethality in 50% of mice. The phenotypic defect is dependent on the genetic background, indicating the presence of genetic modifier loci. We speculate that the further characterization of Mospd3 will shed light on the complex genetic interactions involved in cardiac development and disease.     

The effects of 884 MHz GSM wireless communication signals on headache and other symptoms: an experimental provocation study

Findings from prior studies of possible health and physiological effects from mobile phone use have been inconsistent. Exposure periods in provocation studies have been rather short and personal characteristics of the participants poorly defined. We studied the effect of radiofrequency field (RF) on self-reported symptoms and detection of fields after a prolonged exposure time and with a well defined study group including subjects reporting symptoms attributed to mobile phone use. The design was a double blind, cross-over provocation study testing a 3-h long GSM handset exposure versus sham. The study group was 71 subjects age 18-45, including 38 subjects reporting headache or vertigo in relation to mobile phone use (symptom group) and 33 non-symptomatic subjects. Symptoms were scored on a 7-point Likert scale before, after 1(1/2) and 2(3/4) h of exposure. Subjects reported their belief of actual exposure status. The results showed that headache was more commonly reported after RF exposure than sham, mainly due to an increase in the non-symptom group. Neither group could detect RF exposure better than by chance. A belief that the RF exposure had been active was associated with skin symptoms. The higher prevalence of headache in the non-symptom group towards the end of RF exposure justifies further investigation of possible physiological correlates. The current study indicates a need to better characterize study participants in mobile phone exposure studies and differences between symptom and non-symptom groups.     

ORIGIN AND DIVERSIFICATION OF THE CALIFORNIA FLORA: RE‐EXAMINING CLASSIC HYPOTHESES WITH MOLECULAR PHYLOGENIES

The California Floristic Province exhibits one of the richest floras on the planet, with more than 5500 native plant species, approximately 40% of which are endemic. Despite its impressive diversity and the attention it has garnered from ecologists and evolutionary biologists, historical causes of species richness and endemism in California remain poorly understood. Using a phylogenetic analysis of 16 angiosperm clades, each containing California natives in addition to species found only outside California, we show that CA's current biodiversity primarily results from low extinction rates, as opposed to elevated speciation or immigration rates. Speciation rates in California were lowest among Arcto‐Tertiary lineages (i.e., those colonizing California from the north, during the Tertiary), but extinction rates were universally low across California native plants of all historical, geographic origins. In contrast to long‐accepted ideas, we find that California diversification rates were generally unaffected by the onset of the Mediterranean climate. However, the Mediterranean climate coincided with immigration of many desert species, validating one previous hypothesis regarding origins of CA's plant diversity. This study implicates topographic complexity and climatic buffering as key, long‐standing features of CA's landscape favoring plant species persistence and diversification, and highlights California as an important refuge under changing climates.     

Species loss and gain in communities under future climate change: consequences for functional diversity

It is anticipated that anthropogenic climate change will lead to substantial reassembly within communities in coming decades as individual species shift their ranges to track optimal conditions for growth and survival. As species are lost and gained in communities, what are the consequences for functional trait diversity? Functional traits are the characteristics of species that affect individual performance and provide the vital link between biodiversity at the species level and ecosystem function. We investigated how projected changes in species richness in plant communities under climate change scenarios for the decade 2050 will affect the distribution and diversity of five functional traits. We aggregated range change projections made in Maxent for the decade 2050 across all species in the regional pool of littoral rainforest vines in eastern Australia (n = 163 species). The effect of richness changes on trait diversity was assessed in nine rainforest reserves along the east coast of Australia. Although richness was predicted to significantly decline across all communities, functional diversity remained stable, indicating a decoupling in response to climate change at these two different levels of biological organization. A high degree of redundancy in trait composition in communities may buffer against the loss of function in these plant communities. Scaling‐up our understanding of the impact of climate change from the species level to communities is a critical step towards developing conservation strategies aimed at preserving ecosystem function.     

Polyamines in Human Brain: Regional Distribution and Influence of Aging

Abstract: Depolarization of adult rat forebrain slices with veratrine induced the release of excitatory amino acids (glutamate and aspartate), the synthesis of nitric oxide (NO), and increases in cyclic GMP (cGMP). The NO synthase inhibitors N ^ω-monomethyl- l -arginine and N ^ω-nitro- l -arginine methyl ester decreased the release of NO and the levels of cGMP without affecting the release of excitatory amino acids. In contrast, the antiepileptic drug lamotrigine inhibited the release of excitatory amino acids and of NO, and decreased the levels of cGMP without causing a significant direct inhibition of the NO synthase. Furthermore, the synthesis of NO and the increases in cGMP induced by veratrine were partially blocked by the N -methyl- d -aspartate (NMDA) receptor antagonist MK-801 but not by 6-nitro-7-sulphamobenzo( f )quinoxaline-2,3-dione, a non-NMDA receptor antagonist. Neither of these compounds inhibited directly the NO synthase or the release of excitatory amino acids. Thus, these three types of compound act as an inhibitor of voltage-sensitive sodium channels (lamotrigine), as a receptor antagonist (MK-801), or as direct inhibitors of the NO synthase, to block the pathway leading to increased cGMP after veratrine depolarization. It is likely that some of the pharmacological and therapeutic actions shared by these three types of compound are, at least in part, a consequence of inhibition of the synthesis of NO.     

Morphology,biomass and nutrient status of fine roots of Scots pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis>) as influenced by seasonal fluctuations in soil moisture and soil solution chemistry

A field monitoring study was carried out to follow the changes of fine root morphology, biomass and nutrient status in relation to seasonal changes in soil solution chemistry and moisture regime in a mature Scots pine stand on acid soil. Seasonal and yearly fluctuations in soil moisture and soil solution chemistry have been observed. Changes in soil moisture accounted for some of the changes in the soil solution chemistry. The results showed that when natural acidification in the soil occurs with low pH (3.5–4.2) and high aluminium concentration in the soil solution (>3–10 mg l^–1), fine root longevity and distribution could be affected. However, fine root growth of Scots pine may not be negatively influenced by adverse soil chemical conditions if soil moisture is not a limiting factor for root growth. In contrast, dry soil conditions increase Scots pine susceptibility to soil acidification and this could significantly reduce fine root growth and increase root mortality. It is therefore important to study seasonal fluctuations of the environmental variables when investigating and modelling cause-effect relationships.     

Spatial and temporal variations in species occurrence rate affect the accuracy of occurrence models

Aim Predictive models of species occurrence have potential for prioritizing areas for competing land uses. Before widespread application, however, it is necessary to evaluate performance using independent data and effective accuracy measures. The objectives of this study were to (1) compare the effects of species occurrence rate on model accuracy, (2) assess the effects of spatial and temporal variation in occurrence rate on model accuracy, and (3) determine if the number of predictor variables affected model accuracy. Location We predicted the distributions of breeding birds in three adjacent mountain ranges in the Great Basin (Nevada, USA). Methods For each of 18 species, we developed separate models using five different data sets — one set for each of 2 years (to address the effects of temporal variation), and one set for each of three possible pairs of mountain ranges (to address the effects of spatial variation). We evaluated each model with an independent data set using four accuracy measures: discrimination ability [area under a receiver operating characteristic curve (AUC)], correct classification rate (CCR), proportion of presences correctly classified (sensitivity), and proportion of absences correctly classified (specificity). Results Discrimination ability was not affected by occurrence rate, whereas the other three accuracy measures were significantly affected. CCR, sensitivity and specificity were affected by species occurrence rate in the evaluation data sets to a greater extent than in the model‐building data sets. Discrimination ability was the only accuracy measure affected by the number of variables in a model. Main conclusions Temporal variation in species occurrence appeared to have a greater impact than did spatial variation. When temporal variation in species distributions is great, the relative costs of omission and commission errors should be assessed and long‐term census data should be examined before using predictive models of occurrence in a management setting.     

Renewal ecology: conservation for the Anthropocene

The global scale and rapidity of environmental change is challenging ecologists to reimagine their theoretical principles and management practices. Increasingly, historical ecological conditions are inadequate targets for restoration ecology, geographically circumscribed nature reserves are incapable of protecting all biodiversity, and the precautionary principle applied to management interventions no longer ensures avoidance of ecological harm. In addition, human responses to global environmental changes, such as migration, building of protective infrastructures, and land use change, are having their own negative environmental impacts. We use examples from wildlands, urban, and degraded environments, as well as marine and freshwater ecosystems, to show that human adaptation responses to rapid ecological change can be explicitly designed to benefit biodiversity. This approach, which we call “renewal ecology,” is based on acceptance that environmental change will have transformative effects on coupled human and natural systems and recognizes the need to harmonize biodiversity with human infrastructure, for the benefit of both.