Male reproductive health and environmental xenoestrogens

EHP is a publication of the U.S. government. Publication of EHP lies in the public domain and is therefore without copyright. Research articles from EHP may be used freely; however, articles from the News section of EHP may contain photographs or figures copyrighted by other commercial organizations and individuals that may not be used without obtaining prior approval from both the EHP editors and the holder of the copyright. Use of any materials published in EHP should be acknowledged (for example, "Reproduced with permission from Environmental Health Perspectives") and a reference provided for the article from which the material was reproduced.Male reproductive health has deteriorated in many countries during the last few decades. In the 1990s, declining semen quality has been reported from Belgium, Denmark, France, and Great Britain. The incidence of testicular cancer has increased during the same time incidences of hypospadias and cryptorchidism also appear to be increasing. Similar reproductive problems occur in many wildlife species. There are marked geographic differences in the prevalence of male reproductive disorders. While the reasons for these differences are currently unknown, both clinical and laboratory research suggest that the adverse changes may be inter-related and have a common origin in fetal life or childhood. Exposure of the male fetus to supranormal levels of estrogens, such as diethlylstilbestrol, can result in the above-mentioned reproductive defects. The growing number of reports demonstrating that common environmental contaminants and natural factors possess estrogenic activity presents the working hypothesis that the adverse trends in male reproductive health may be, at least in part, associated with exposure to estrogenic or other hormonally active (e.g., antiandrogenic) environmental chemicals during fetal and childhood development. An extensive research program is needed to understand the extent of the problem, its underlying etiology, and the development of a strategy for prevention and intervention.Supported by EU Contract BMH4-CT96-0314

Counter-Gradient Variation in Respiratory Performance of Coral Reef Fishes at Elevated Temperatures

The response of species to global warming depends on how different populations are affected by increasing temperature throughout the species' geographic range. Local adaptation to thermal gradients could cause populations in different parts of the range to respond differently. In aquatic systems, keeping pace with increased oxygen demand is the key parameter affecting species' response to higher temperatures. Therefore, respiratory performance is expected to vary between populations at different latitudes because they experience different thermal environments. We tested for geographical variation in respiratory performance of tropical marine fishes by comparing thermal effects on resting and maximum rates of oxygen uptake for six species of coral reef fish at two locations on the Great Barrier Reef (GBR), Australia. The two locations, Heron Island and Lizard Island, are separated by approximately 1200 km along a latitudinal gradient. We found strong counter-gradient variation in aerobic scope between locations in four species from two families (Pomacentridae and Apogonidae). High-latitude populations (Heron Island, southern GBR) performed significantly better than low-latitude populations (Lizard Island, northern GBR) at temperatures up to 5°C above average summer surface-water temperature. The other two species showed no difference in aerobic scope between locations. Latitudinal variation in aerobic scope was primarily driven by up to 80% higher maximum rates of oxygen uptake in the higher latitude populations. Our findings suggest that compensatory mechanisms in high-latitude populations enhance their performance at extreme temperatures, and consequently, that high-latitude populations of reef fishes will be less impacted by ocean warming than will low-latitude populations

Soil warming accelerates decomposition of fine woody debris

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Plant and Soil 356 (2012): 405-417, doi:10.1007/s11104-012-1130-x.Soil warming from global climate change could increase decomposition of fine woody debris (FWD), but debris size and quality may mitigate this effect. The goal of this study was to investigate the effect of soil warming on decomposition of fine woody debris of differing size and quality. We placed FWD of two size classes (2 × 20 cm and 4 × 40 cm) and four species (Acer saccharum, Betula lenta, Quercus rubra and Tsuga canadensis) in a soil warming and ambient area at Harvard Forest in central Massachusetts. We collected the debris from each area over two years and measured mass loss and lignin concentration. Warming increased mass loss for all species and size classes (by as much as 30%), but larger debris and debris with higher initial lignin content decomposed slower than smaller debris and debris with lower initial lignin content. Lignin degradation did not follow the same trends as mass loss. Lignin loss from the most lignin-rich species, T. canadensis, was the highest despite the fact that it lost mass the slowest. Our results suggest that soil warming will increase decomposition of FWD in temperate forests. It is imperative that future models and policy efforts account for this potential shift in the carbon storage pool

Carbogen-induced changes in rat mammary tumour oxygenation reported by near infrared spectroscopy

We have evaluated the ability of steady-state, radially-resolved, broad-band near infrared diffuse reflectance spectroscopy to measure carbogen-induced changes in haemoglobin oxygen saturation (SO2) and total haemoglobin concentration in a rat R3230 mammary adenocarcinoma model in vivo. Detectable shifts toward higher saturations were evident in all tumours (n = 16) immediately after the onset of carbogen breathing. The SO2 reached a new equilibrium within 1 min and remained approximately constant during 200–300 s of administration. The return to baseline saturation was more gradual when carbogen delivery was stopped. The degree to which carbogen increased SO2 was variable among tumours, with a tendency for tumours with lower initial SO2 to exhibit larger changes. Tumour haemoglobin concentrations at the time of peak enhancement were also variable. In the majority of cases, haemoglobin concentration decreased in response to carbogen, indicating that increased tumour blood volume was not responsible for the observed elevation in SO2. We observed no apparent relationship between the extent of the change in tumour haemoglobin concentration and the magnitude of the change in the saturation. Near infrared diffuse reflectance spectroscopy provides a rapid, non-invasive means of monitoring spatially averaged changes in tumour haemoglobin oxygen saturation induced by oxygen modifiers. © 1999 Cancer Research Campaig

Effects of enamel matrix derivative and transforming growth factor-β1 on human osteoblastic cells

<p>Abstract</p> <p>Background</p> <p>Extracellular matrix proteins are key factors that influence the regenerative capacity of tissues. The objective of the present study was to evaluate the effects of enamel matrix derivative (EMD), TGF-β1, and the combination of both factors (EMD+TGF-β1) on human osteoblastic cell cultures.</p> <p>Methods</p> <p>Cells were obtained from alveolar bone of three adult patients using enzymatic digestion. Effects of EMD, TGF-β1, or a combination of both were analyzed on cell proliferation, bone sialoprotein (BSP), osteopontin (OPN) and alkaline phosphatase (ALP) immunodetection, total protein synthesis, ALP activity and bone-like nodule formation.</p> <p>Results</p> <p>All treatments significantly increased cell proliferation compared to the control group at 24 h and 4 days. At day 7, EMD group showed higher cell proliferation compared to TGF-β1, EMD + TGF-β1 and the control group. OPN was detected in the majority of the cells for all groups, whereas fluorescence intensities for ALP labeling were greater in the control than in treated groups; BSP was not detected in all groups. All treatments decreased ALP levels at 7 and 14 days and bone-like nodule formation at 21 days compared to the control group.</p> <p>Conclusions</p> <p>The exposure of human osteoblastic cells to EMD, TGF-β1 and the combination of factors <it>in vitro </it>supports the development of a less differentiated phenotype, with enhanced proliferative activity and total cell number, and reduced ALP activity levels and matrix mineralization.</p

Carrion Availability in Space and Time

Introduction Availability of carrion to scavengers is a central issue in carrion ecology and management, and is crucial for understanding the evolution of scavenging behaviour. Compared to live animals, their carcasses are relatively unpredictable in space and time in natural conditions, with a few exceptions (see below, especially Sect. “Carrion Exchange at the Terrestrial-Aquatic Interface”). Carrion is also an ephemeral food resource due to the action of a plethora of consumers, from microorganisms to large vertebrates, as well as to desiccation (i.e., loss of water content; DeVault et al. 2003; Beasley et al. 2012; Barton et al. 2013; Moleón et al. 2014). With a focus on vertebrate carcasses, here we give an overview of (a) the causes that produce carrion, (b) the rate of carrion production, (c) the factors affecting carrion quality, and (d) the distribution of carrion in space and time, both in terrestrial and aquatic environments (including their interface). In this chapter, we will focus on naturally produced carrion, whereas non-natural causes of animal mortality are described in chapter “Human-Mediated Carrion: Effects on Ecological Processes”. However, throughout this chapter we also refer to extensive livestock carrion, because in the absence of strong restrictions such as those imposed in the European Community after the bovine spongiform encephalopathy crisis (Donázar et al. 2009; Margalida et al. 2010), the spatiotemporal availability of carrion of extensive livestock and wild ungulates is similar

Knockdown of brain-derived neurotrophic factor in specific brain sites precipitates behaviors associated with depression and reduces neurogenesis

Depression has been associated with reduced expression of brain-derived neurotrophic factor (BDNF) in the hippocampus. In addition, animal studies suggest an association between reduced hippocampal neurogenesis and depressive-like behavior. These associations were predominantly established based on responses to antidepressant drugs and alterations in BDNF levels and neurogenesis in depressive patients or animal models for depressive behavior. Nevertheless, there is no direct evidence that the actual reduction of the BDNF protein in specific brain sites can induce depressive-like behaviors or affect neurogenesis in vivo. Using BDNF knockdown by RNA interference and lentiviral vectors injected into specific subregions of the hippocampus we show that a reduction in BDNF expression in the dentate gyrus, but not the CA3, reduces neurogenesis and affects behaviors associated with depression. Moreover, we show that BDNF has a critical function in neuronal differentiation, but not proliferation in vivo. Finally, we found that a specific BDNF knockdown in the ventral subiculum induces anhedonic-like behavior. These findings provide substantial support for the neurotrophic hypothesis of depression and specify anatomical and neurochemical targets for potential antidepressant interventions. Moreover, the specific effect of BDNF reduction on neuronal differentiation has broader implications for the study of neurodevelopment and neurodegenerative diseases

Meso- and macrozooplankton communities in the Weddell Sea, Antarctica

The present paper describes composition and abundance of meso- and macrozooplankton in the epipelagic zone of the Weddell Sea and gives a systematic review of encountered species regarding results of earlier expeditions. Material was sampled from 6 February to 10 March 1983 from RV Polarstern with a RMT 1+8 m (320 and 4500 μm mesh size). In agreement with topography and water mass distribution three distinct communities were defined, clearly separated by cluster analysis: The Southern Shelf Community has lowest abundances (approx. 9000 ind./1000 m3). Euphausia crystallorophias and Metridia gerlachei are predominating. Compared with the low overall abundance the number of regularly occurring species is high (55) due to many neritic forms. Herbivores and omnivores are dominating (58% and 35%). The North-eastern Shelf Community has highest abundances (about 31 000 ind./1000 m3). It is predominated by copepodites I–III of Calanus propinquus and Calanoides acutus (61%). The faunal composition is characterized by both oceanic and neritic species (64). Fine-filter feeders are prevailing (65%). The Oceanic Community has a mean abundance of approximately 23 000 ind./1000 m3, consisting of 61 species. Dominances are not as pronounced as in the shelf communities. Apart from abundant species like Calanus propinquus, Calanoides acutus, Metridia gerlachei, Oithona spp. and Oncaea spp. many typical inhabitants of the Eastwind Drift are encountered. All feeding types have about the same importance in the Oceanic Community

Speed kills: ineffective avian escape responses to oncoming vehicles

Animal–vehicle collisions cause high levels of vertebrate mortality worldwide, and what goes wrong when animals fail to escape and ultimately collide with vehicles is notwell understood.We investigated alert and escape behaviours of captive brown-headed cowbirds (Molothrus ater) in response to virtual vehicle approaches of different sizes and at speeds ranging from 60 to 360 km h-1. Alert and flight initiation distances remained similar across vehicle speeds, and accordingly, alert and flight initiation times decreased at higher vehicle speeds. Thus, avoidance behaviours in cowbirds appeared to be based on distance rather than time available for escape, particularly at 60–150 km h-1; however, at higher speeds (more than or equal to 180 km h-1) no trend in response behaviour was discernible. As vehicle speed increased, cowbirds did not have enough time to assess the approaching vehicle, and cowbirds generally did not initiate flight with enough time to avoid collision when vehicle speed exceeded 120 km h-1. Although potentially effective for evading predators, the decision-making process used by cowbirds in our study appears maladaptive in the context of avoiding fast-moving vehicles. Our methodological approach and findings provide a framework to assess how novel management strategies could affect escape rules, and the sensory and cognitive abilities animals use to avoid vehicle collisions