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The reticulated flatwoods salamander (Ambystoma bishopi), an endangered species endemic to the longleaf-pine savanna ecosystem of the southeastern U.S., persists in a small number of remnant habitat patches. Breeding ponds and associated populations are threatened by habitat loss, degradation, and fragmentation stemming from fire suppression and land conversion. Understanding influences on population dynamics and genetic diversity will help inform recovery efforts for this and other pond-breeding amphibians. We used 9 microsatellite loci to characterize population structure, migration, and genetic diversity of juvenile (larvae and metamorphs) A. bishopi (n = 607) sampled from thirteen breeding ponds across two breeding seasons. Temporal genetic variation between annual cohorts was minimal compared to spatial variation among locations. The primary genetic subdivision was between two regional groups of breeding ponds (i.e. metapopulations), which were located more than 10 km from each other. Yet even within metapopulations, genetic isolation-by-distance was pronounced, and estimated migration rates among ponds separated by > 400 m were very low. Genetic diversity was positively correlated with the area of suitable breeding habitat in a pond and negatively correlated with distance to other occupied ponds. The effective number of breeders typically was

Reticulated flatwoods salamander (Ambystoma bishopi) populations began decreasing dramatically in the 1900s. Contemporary populations are small, isolated, and may be susceptible to inbreeding and reduced adaptive potential because of low genetic variation. Genetic variation at immune genes is especially important as it influences disease susceptibility and adaptation to emerging infectious pathogens, a central conservation concern for declining amphibians. We collected samples from across the extant range of this salamander to examine genetic variation at major histocompatibility complex (MHC) class Iα and IIβ exons as well as the mitochondrial control region. We screened tail or toe tissue for ranavirus, a pathogen associated with amphibian declines worldwide. Overall, we found low MHC variation when compared to other amphibian species and did not detect ranavirus at any site. MHC class Iα sequencing revealed only three alleles with a nucleotide diversity of 0.001, while MHC class IIβ had five alleles with a with nucleotide diversity of 0.004. However, unique variation still exists across this species' range with private alleles at three sites. Unlike MHC diversity, mitochondrial variation was comparable to levels estimated for other amphibians with nine haplotypes observed, including one haplotype shared across all sites. We hypothesize that a combination of a historic disease outbreak and a population bottleneck may have contributed to low MHC diversity while maintaining higher levels of mitochondrial DNA variation. Ultimately, MHC data indicated that the reticulated flatwoods salamander may be at an elevated risk from infectious diseases due to low levels of immunogenetic variation necessary to combat novel pathogens.

In the new 2017 WHO classification, a reduction of the high number of entities of salivary carcinomas was implemented. There is only one new carcinoma entity: secretory carcinoma. There is a slight increase of reactive and benign entities by the inclusion of rare and well-established, but so far not included, lesions. Furthermore, there are some conceptual changes and pure changes in terminology. The impact of molecular findings is increasing and is so far restricted to diagnostic aspects.

Ephemeral wetlands provide breeding habitat for many amphibian species, and wetland hydrology plays a crucial role in determining amphibian breeding success. We discuss the potential influence of recession rates (i.e., rate of water level decline) and empirically evaluate them in wetlands inhabited by the endangered reticulated flatwoods salamander (Ambystoma bishopi). Rapid water level declines are potentially problematic for reticulated flatwoods salamanders because this species has a long development period, with metamorphosis generally occurring from March to May when groundwater losses are combined with high evapotranspiration rates. To evaluate magnitude, variability, and drivers of recession rates, we monitored water levels in 33 wetlands in the Florida panhandle and examined recession rates during the flatwoods salamander reproductive period. After controlling for the effects of specific yield, standardized recession rates were, on average, 3.9 times daily potential evapotranspiration rates, suggesting that groundwater fluxes are an important driver of water level declines in these wetlands. Standardized recession rates were variable across the landscape and increased with decreasing wetland size, indicating that larger wetlands are often hydrologically more suitable for flatwoods salamanders. This work points to these and other controls on wetland recession rates and their role in regulating amphibian reproductive success.

Changing climate will impact species' ranges only when environmental variability directly impacts the demography of local populations. However, measurement of demographic responses to climate change has largely been limited to single species and locations. Here we show that amphibian communities are responsive to climatic variability, using >500,000 time-series observations for 81 species across 86 North American study areas. The effect of climate on local colonization and persistence probabilities varies among eco-regions and depends on local climate, species life-histories, and taxonomic classification. We found that local species richness is most sensitive to changes in water availability during breeding and changes in winter conditions. Based on the relationships we measure, recent changes in climate cannot explain why local species richness of North American amphibians has rapidly declined. However, changing climate does explain why some populations are declining faster than others. Our results provide important insights into how amphibians respond to climate and a general framework for measuring climate impacts on species richness. John Wesley Powell Center for Analysis and Synthesis - US Geological Survey U.S. Geological Survey-Amphibian Research and Monitoring Initiative (ARMI) U.S. Fish and Wildlife Service National Park Service U.S. Forest Service National Science Foundation [DEB-0841758, DEB-1149308] National Institutes of Health [R01GM109499] National Geographic Society Morris Animal Foundation David and Lucille Packard Foundation This work was conducted as part of the Amphibian Decline Working Group supported by the John Wesley Powell Center for Analysis and Synthesis, funded by the US Geological Survey. Funding and logistical support for field data collection came from a range of sources including the U.S. Geological Survey-Amphibian Research and Monitoring Initiative (ARMI), U.S. Fish and Wildlife Service, National Park Service, U.S. Forest Service, National Science Foundation (DEB-0841758, DEB-1149308), National Institutes of Health (R01GM109499), National Geographic Society, Morris Animal Foundation, and David and Lucille Packard Foundation. Data are deposited at the U.S. Geological Survey's John Wesley Powell Center for Analysis and Synthesis. This manuscript is contribution 654 of USGS ARMI. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Natural disturbances play a critical role in structuring many ecosystems. In the southeastern United States, fire suppression and exclusion have removed the natural disturbance regime from many ecosystems, including ephemeral wetlands embedded within longleaf pine forests. We sampled aquatic invertebrate and amphibian communities in 21 pine flatwoods wetlands in northwest Florida from 2012 to 2014. Our objectives were to quantify amphibian and invertebrate community structure, identify differences in amphibian communities across an environmental gradient, and identify how invertebrate communities responded to wetland habitat characteristics. Amphibian communities were more diverse in wetlands with longer hydroperiods but were similar across wetlands with different vegetation structures. To examine the effects of wetland characteristics on aquatic invertebrate communities, we created a set of a priori models relating the abundance of isopods, chironomids, and damselflies to wetland characteristics. The best-approximating models indicated that isopods and damselflies were more abundant in wetlands that were not fire-suppressed. Similarly, total invertebrate abundance was higher in sections of wetlands with low canopy cover when compared to sections of the same wetlands with high canopy cover. Restoration of vegetation structure in wetlands that have experienced long-term fire suppression and wetlands that support longer hydroperiods should be a management priority.

The flatwoods salamander (Ambystoma cingulatum) was listed as federally threatened in 1999. Alteration of habitat was considered the main threat to the species, especially the loss of habitat for larval flatwoods salamanders that develop in isolated, seasonally flooded wetlands. Our objectives were to evaluate a suite of within-pool factors (i.e., vegetation structure, water level, and an index to presence of fish) that could influence occupancy of breeding wetlands by larval flatwoods salamanders on Eglin Air Force Base in Florida, USA. We dip-netted for larval salamanders from January through March 2003–2006 and we measured a suite of vegetation characteristics in 2006–2007. Further, in 2006 we measured the level of water and relative presence of fish over the salamander breeding season. Site occupancy over the four year period was best described by a model that incorporated high herbaceous vegetation cover and open canopy cover. Detection probability was assessed, but it varied among years and was not included in the model. Our study suggests that managing the breeding habitat of flatwoods salamander for open canopies and dense herbaceous vegetation may contribute to this species’ recovery.

Gene therapy in the central nervous system (CNS) is hindered by the presence of the blood-brain barrier, which restricts access of serum constituents and peripheral cells to the brain parenchyma. Expression of exogenously administered genes in the CNS has been achieved in vivo using highly invasive routes, or ex vivo relying on the direct implantation of genetically modified cells into the brain. Here we provide evidence for a novel, noninvasive approach for targeting potential therapeutic factors to the CNS. Genetically-modified hematopoietic cells enter the CNS and differentiate into microglia after bone-marrow transplantation. Up to a quarter of the regional microglial population is donor-derived by four months after transplantation. Microglial engraftment is enhanced by neuropathology, and gene-modified myeloid cells are specifically attracted to the sites of neuronal damage. Thus, microglia may serve as vehicles for gene delivery to the nervous system.

CASK is a multi-domain scaffolding protein that interacts with the transcription factor TBR1 and regulates expression of genes involved in cortical development such as RELN. Here we describe a previously unreported X-linked brain malformation syndrome caused by mutations of CASK. All five affected individuals with CASK mutations had congenital or postnatal microcephaly, disproportionate brainstem and cerebellar hypoplasia, and severe mental retardation.

Nat. Genet. 40, 1065–1067 (2008); published online 10 August 2008; corrected after print 29 October 2008 In the version of this article initially published, there was an error in the text on page 1066. The protein interacting with CASK is the CASK interacting nucleosome assembly protein (CINAP/TSPYL2) and not the TATA-binding protein associated factor TAF9.