Lead in Ammunition: A Persistent Threat to Health and Conservation

Many scavenging bird populations have experienced abrupt declines across the globe, and intensive recovery activities have been necessary to sustain several species, including the critically endangered California condor (Gymnogyps californianus). Exposure to lead from lead-based ammunition is widespread in condors and lead toxicosis presents an immediate threat to condor recovery, accounting for the highest proportion of adult mortality. Lead contamination of carcasses across the landscape remains a serious threat to the health and sustainability of scavenging birds, and here we summarize recent evidence for exposure to lead-based ammunition and health implications across many species. California condors and other scavenging species are sensitive indicators of the occurrence of lead contaminated carcasses in the environment. Transdisciplinary science-based approaches have been critical to managing lead exposure in California condors and paving the way for use of non-lead ammunition in California. Similar transdisciplinary approaches are now needed to translate the science informing on this issue and establish education and outreach efforts that focus on concerns brought forth by key stakeholders.     

Temporal variability is a personalized feature of the human microbiome

Background

It is now apparent that the complex microbial communities found on and in the human body vary across individuals. What has largely been missing from previous studies is an understanding of how these communities vary over time within individuals. To the extent to which it has been considered, it is often assumed that temporal variability is negligible for healthy adults. Here we address this gap in understanding by profiling the forehead, gut (fecal), palm, and tongue microbial communities in 85 adults, weekly over 3 months.

Results

We found that skin (forehead and palm) varied most in the number of taxa present, whereas gut and tongue communities varied more in the relative abundances of taxa. Within each body habitat, there was a wide range of temporal variability across the study population, with some individuals harboring more variable communities than others. The best predictor of these differences in variability across individuals was microbial diversity; individuals with more diverse gut or tongue communities were more stable in composition than individuals with less diverse communities.

Conclusions

Longitudinal sampling of a relatively large number of individuals allowed us to observe high levels of temporal variability in both diversity and community structure in all body habitats studied. These findings suggest that temporal dynamics may need to be considered when attempting to link changes in microbiome structure to changes in health status. Furthermore, our findings show that, not only is the composition of an individual’s microbiome highly personalized, but their degree of temporal variability is also a personalized feature.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-014-0531-y) contains supplementary material, which is available to authorized users.     

Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California

Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats.     

A novel cell death pathway that is partially caspase dependent, but morphologically non-apoptotic, elicited by proteasomal inhibition of rat sympathetic neurons

Proteasomal dysfunction has been linked to neurodegeneration. Pharmacological proteasomal inhibitors may have pro-survival or pro-death effects in neuronal cells. We have previously found that application of such agents to mouse sympathetic neurons leads to activation of the intrinsic apoptotic pathway. We show here that in rat sympathetic neurons proteasomal inhibition leads to a form of death that is morphologically non-apoptotic, with features of autophagy. The intrinsic apoptotic pathway is activated in a delayed fashion compared with mouse neurons, and is in part responsible for death, as evidenced by the partial protective effects of bcl-xL and the general caspase inhibitor Boc-aspartyl-fluoromethylketone. Death is accompanied by induction of Bim and caspase activation, but caspase 3 activation is lacking; 3-methyl-adenine inhibits macroautophagy, but has a relatively small pro-survival effect. We conclude that a complex array of pro- and anti-apoptotic effects elicited by proteasomal inhibition in rat sympathetic neurons leads to partial engagement of the intrinsic apoptotic pathway and a morphologically non-apoptotic, autophagic form of death. The species difference with mouse neurons is underscored by the fact that proteasomal inhibitors are protective against apoptosis elicited by nerve growth factor deprivation in rat, but not mouse, sympathetic neurons. The type of death described herein may be relevant to neurodegenerative diseases, where morphological evidence for apoptosis has been scant.     

RAIDD aggregation facilitates apoptotic death of PC12 cells and sympathetic neurons

In human cell lines, the caspase 2 adaptor RAIDD interacts selectively with caspase 2 through its caspase recruitment domain (CARD) and leads to caspase 2-dependent death. Whether RAIDD induces such effects in neuronal cells is unknown. We have previously shown that caspase 2 is essential for apoptosis of trophic factor-deprived PC12 cells and rat sympathetic neurons. We report here that rat RAIDD, cloned from PC12 cells, interacts with rat caspase 2 CARD. RAIDD overexpression induced caspase 2 CARD- and caspase 9-dependent apoptosis of PC12 cells and sympathetic neurons. Apoptosis correlated with the formation of discrete perinuclear aggregates. Both death and aggregates required the expression of full-length RAIDD. Such aggregates may enable more effective activation of caspase 2 through close proximity. Following trophic deprivation, RAIDD overexpression increased death and aggregate formation. Therefore, RAIDD aggregation is important for its death-promoting effects and may play a role in trophic factor withdrawal-induced neuronal apoptosis.     

Lethal and sublethal effects of a neem-based insecticide on balsam fir sawfly (Hymenoptera: Diprionidae)

Lethal and sublethal effects of Neemix 4.5 EC, a commercial neem preparation, on balsam fir sawfly, Neodiprion abietis (Harris), were determined in the laboratory. Larval mortality of N. abietis increased in a concentration-dependent manner, and lethal time decreased with increasing Neemix 4.5 EC concentration. Fifty percent of the larvae died after 4.6 d at a concentration of 90 ppm azadirachtin (AZA) and 12.3 d at a concentration of 0.08 ppm. Neemix 4.5 EC showed some deterrent effects to feeding site selection on N. abietis larvae at high concentrations, but not at low concentrations. Strong reduction of food intake by N. abietis larvae after exposure to Neemix 4.5 EC was demonstrated by significant reduction of frass production. Larvae fed on Neemix 4.5 EC-treated foliage at 90 ppm AZA produced only 16% as much frass as that produced by larvae fed on control foliage (0 ppm). Neemix 4.5 EC at a concentration of 0.08 ppm AZA retarded larval and pupal development. Sublethal doses significantly reduced pupal weight and adult emergence, although the sex ratio of N. abietis adults was not affected. Results indicate that sublethal effects of Neemix 4.5 EC on N. abietis may contribute greatly to the overall field efficacy.     

Ubiquitinated inclusions and neuronal cell death

Ubiquitinated inclusions and selective neuronal cell death are considered the pathological hallmarks of Parkinson's disease and other neurodegenerative diseases. Recent genetic, pathological and biochemical evidence suggests that dysfunction of ubiquitin-dependent protein degradation by the proteasome might be a contributing, if not initiating factor in the pathogenesis of these diseases. In neuronal cell culture models inhibition of the proteasome leads to cell death and formation of fibrillar ubiquitin and alpha-synuclein-positive inclusions, thus modeling some aspects of Lewy body diseases. The processes of inclusion formation and neuronal cell death share some common mechanisms, but can also be dissociated at a certain level.