Changing Patterns of Microhabitat Utilization by the Threespot Damselfish, Stegastes planifrons, on Caribbean Reefs

Background: The threespot damselfish, Stegastes planifrons (Cuvier), is important in mediating interactions among corals, algae, and herbivores on Caribbean coral reefs. The preferred microhabitat of S. planifrons is thickets of the branching staghorn coral Acropora cervicornis. Within the past few decades, mass mortality of A. cervicornis from white-band disease and other factors has rendered this coral a minor ecological component throughout most of its range. Methodology/Principal Findings: Survey data from Jamaica (heavily fished), Florida and the Bahamas (moderately fished), the Cayman Islands (lightly to moderately fished), and Belize (lightly fished) indicate that distributional patterns of S. planifrons are positively correlated with live coral cover and topographic complexity. Our results suggest that speciesspecific microhabitat preferences and the availability of topographically complex microhabitats are more important than the abundance of predatory fish as proximal controls on S. planifrons distribution and abundance. Conclusions/Significance: The loss of the primary microhabitat of S. planifrons—A. cervicornis—has forced a shift in the distribution and recruitment of these damselfish onto remaining high-structured corals, especially the Montastraea annulari

Altered glycogen metabolism in cultured astrocytes from mice with chronic glutathione deficit; relevance for neuroenergetics in schizophrenia.

Neurodegenerative and psychiatric disorders including Alzheimer's, Parkinson's or Huntington's diseases and schizophrenia have been associated with a deficit in glutathione (GSH). In particular, a polymorphism in the gene of glutamate cysteine ligase modulatory subunit (GCLM) is associated with schizophrenia. GSH is the most important intracellular antioxidant and is necessary for the removal of reactive by-products generated by the utilization of glucose for energy supply. Furthermore, glucose metabolism through the pentose phosphate pathway is a major source of NADPH, the cofactor necessary for the regeneration of reduced glutathione. This study aims at investigating glucose metabolism in cultured astrocytes from GCLM knockout mice, which show decreased GSH levels. No difference in the basal metabolism of glucose was observed between wild-type and knockout cells. In contrast, glycogen levels were lower and its turnover was higher in knockout astrocytes. These changes were accompanied by a decrease in the expression of the genes involved in its synthesis and degradation, including the protein targeting to glycogen. During an oxidative challenge induced by tert-Butylhydroperoxide, wild-type cells increased their glycogen mobilization and glucose uptake. However, knockout astrocytes were unable to mobilize glycogen following the same stress and they could increase their glucose utilization only following a major oxidative insult. Altogether, these results show that glucose metabolism and glycogen utilization are dysregulated in astrocytes showing a chronic deficit in GSH, suggesting that alterations of a fundamental aspect of brain energy metabolism is caused by GSH deficit and may therefore be relevant to metabolic dysfunctions observed in schizophrenia

Seroprevalence of Ehrlichia canis, Ehrlichia chaffeensis and Ehrlichia ewingii in dogs in North America

Background: This study evaluated the exposure of dogs to three different Ehrlichia spp. in the south and central regions of the United States where vector-borne disease prevalence has been previously difficult to ascertain, particularly beyond the metropolitan areas. Methods: Dog blood samples (n = 8,662) were submitted from 14 veterinary colleges, 6 private veterinary practices and 4 diagnostic laboratories across this region. Samples were tested for E. canis, E. chaffeensis and E. ewingii specific antibodies using peptide microtiter ELISAs. Results: Overall, E. canis, E. chaffeensis and E. ewingii seroprevalence was 0.8%, 2.8%, and 5.1%, respectively. The highest E. canis seroprevalence (2.3%) was found in a region encompassing Arkansas, Louisiana, Oklahoma, Tennessee and Texas. E. chaffeensis seroreactivity was 6.6% in the central region (Arkansas, Kansas, Missouri, and Oklahoma) and 4.6% in the southeast region (Georgia, Maryland, North Carolina, South Carolina, Tennessee and Virginia). Seroreactivity to E. ewingii was also highest in the central region (14.6%) followed by the southeast region (5.9%). The geospatial pattern derived from E. chaffeensis and E. ewingii seropositive samples was similar to previous reports based on E. chaffeensis seroreactivity in white-tailed deer and the distribution of human monocytic ehrlichiosis (HME) cases reported by the CDC. Conclusions: The results of this study provide the first large scale regional documentation of exposure to E. canis, E. chaffeensis and E. ewingii in pet dogs, highlighting regional differences in seroprevalence and providing the basis for heightened awareness of these emerging vector-borne pathogens by veterinarians and public health agencies

Analyzing antimicrobial resistance as a series of collective action problems

Publication status: PublishedAbstractAntimicrobial resistance (AMR) causes over 1.27 million deaths annually, making it one of today's most urgent health threats. Given its urgency, there are often calls for large‐scale global initiatives to address AMR. However, theories of collective action have yet to be applied to the problem in a systematic and holistic manner. Fuller engagement with collective action theory is necessary to avoid three risks, namely: mischaracterizing the kinds of challenges that AMR presents; over‐simplifying the problem by reducing it to a single type of collective action problem while ignoring others; and overstating the ability of collective action theory to formulate effective solutions. This article relies on the work of Elinor Ostrom to develop an analytical framework for collective action problems around public and common goods. When analyzed through this framework, we find that AMR poses at least nine distinct collective action problems. This more granular framing of AMR provides, in our view, a better basis to develop policy solutions to address this multifaceted challenge. We conclude with proposals for future research.</jats:p

Analyzing Antimicrobial Resistance as a Series of Collective Action Problems

Antimicrobial resistance (AMR) causes over 1.27 million deaths annually, making it one of today’s most urgent health threats. Given its urgency, there are often calls for large-scale global initiatives to address AMR. However, collective action theory has yet to be applied to the problem in a systematic and holistic manner. Fuller engagement with collective action theory is necessary to avoid three risks, namely: mischaracterizing the kinds of challenges that AMR presents; over-simplifying the problem by reducing it to a single type of collective action problem; and overstating the ability of collective action theory to formulate effective solutions. This article relies on the work of Elinor Ostrom to develop an analytical framework for collective action problems concerning public goods (non-excludable and non-rivalrous) and common goods (non-excludable and rivalrous). When analyzed through this framework, we find that AMR poses nine distinct collective action problems. This more granular framing of AMR provides, in our view, a better basis to develop policy solutions to address the multifaceted challenge of AMR. We conclude with proposals for future research