We examined the seasonal variation in total non-structural carbohydrate (TNC) concentrations in branch, trunk, and root tissues of Anacardium excelsum, Luehea seemannii, Cecropia longipes, and Urera caracasana growing in a seasonally dry forest in Panama. Our main goals were: (1) to determine the main sites of carbohydrate storage, and (2) to determine if seasonal patterns of carbohydrate storage are related to seasonal asynchronies in carbon supply and demand. We expected asynchronies to be related to seasonal variation in water and light availability and to foliar and reproductive phenology. Cecropia and Urera are fully drought-deciduous and so we expected them to exhibit the most dramatic seasonal variation in TNC concentrations. We predicted that maximum carbon supply would occur when canopies were at their fullest and that maximum carbon demand would occur when leaves, flowers, and fruits were produced. The concentration of total non-structural carbohydrates was assessed monthly in wood tissue of roots and in wood and bark tissue of terminal branches. Trunk tissue was sampled bimonthly. All tissues sampled served as storage sites for carbohydrates. As predicted, TNC concentrations varied most dramatically in branches of Cecropia and Urera: a 4-fold difference was observed between dry season maxima and wet season minima in branch wood tissue. Peak concentrations exceeded 25% in Urera and 30% in Cecropia. Less dramatic but significant seasonal variation was observed in Anacardium and Luehea. In all species, minimum branch TNC concentrations were measured during canopy rebuilding. In Anacardium, maximum branch TNC concentrations occurred when canopies were at their fullest. In Cecro-pia, Urera, and Luehea, TNC concentrations continued to increase even as canopies thinned in the early dry season. The greater photosynthetic capacity of leaves produced at the beginning of the dry season and the potential for the export of carbohydrates from senescing leaves may explain this pattern. In all species, the phenology of carbon gain was more important than the phenology of reproduction in influencing seasonal carbohydrate patterns. The combination of high TNC concentrations and the large biomass of branches, trunks, and roots indicates these species are storing and moving large quantities of carbohydrates.

SUMMARY The P7C3 class of neuroprotective aminopropyl carbazoles has been shown to block neuronal cell death in models of neurodegeneration. We now show that P7C3 molecules additionally preserve axonal integrity after injury, before neuronal cell death occurs, in a rodent model of blast-mediated traumatic brain injury (TBI). This protective quality may be linked to the ability of P7C3 molecules to activate nicotinamide phosphoribosyltransferase, the rate-limiting enzyme in nicotinamide adenine dinucleotide salvage. Initiation of daily treatment with our recently reported lead agent, P7C3-S243, one day after blast-mediated TBI blocks axonal degeneration and preserves normal synaptic activity, learning and memory, and motor coordination in mice. We additionally report persistent neurologic deficits and acquisition of an anxiety-like phenotype in untreated animals eight months after blast exposure. Optimized variants of P7C3 thus offer hope for identifying neuroprotective agents for conditions involving axonal damage, neuronal cell death, or both, such as occurs in TBI.

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The magnitude of bacterial diarrhea in developing countries is largely unknown since affordable detection methods are not available. We have developed a PCR-based assay for use in areas with limited resources to screen for diarrheagenic strains from clinical isolates. To simplify the assay and minimize reagents, our method implemented the use of plasmids rather than bacteria as template controls, and the use of bacterial suspensions or crude DNA preparations rather than purified genomic DNA as template DNA. The assay consisted of 3 PCR reactions using 3 groups of 5–6 primer pairs to identify the 11 most common bacterial diarrheogenic pathogens. The three-reaction multiplex PCR amplifies DNA targets specific for each one of the six E. coli diarrheogenic strains and the five non-E. coli diarrheogenic strains, including Salmonella spp, Shigella spp, Campylobacter spp., Yersinia enterocolitica, and Vibrio cholerae. The assay may provide an important epidemiological tool to investigate the role of diarrheagenic bacterial pathogens in areas of the world with limited resources.

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Summary 1.Piper arieianum, an evergreen, understorey shrub of lowland moist forests of Central and South America, exhibits marked seasonal variation in reproductive activity even though climatic variation is low at the study site. Despite a lack of climatic seasonality, previous experimental leaf removal suggested that carbohydrate accumulation is seasonal, occurring prior to flowering. 2. We first tested the hypothesis that carbohydrates necessary for reproduction are accumulated prior to flowering, rather than during or after. By measuring nonstructural carbohydrate production in the form of glucose and starch we found that the concentration of these reserves is greatest 1-3 months before flowering, decreasing by 50% during peak fruit maturation. 3. The hypothesis that reproduction was the cause of this decrease in carbohydrate reserves was then tested by comparing reserves in plants that were prevented from flowering with those that flowered and produced fruit naturally. As predicted, reserves declined more in flowering than in non-flowering plants. A smaller decline in reserves of non-flowering plants was accompanied by greater stem and leaf production, suggesting that stored carbohydrates are also required for growth. 4. Because concentrations of non-structural carbohydrates were similar in roots, stems and leaves, and because the greatest amount of plant biomass is in stems for plants of a range of sizes, stems appear to be the main storage site of carbohydrate reserves in this plant species. 5. These results, together with previous studies, demonstrate that the impact of leaf herbivory on seed production in P. arieianum depends on the timing of that herbivory relative to the accumulation and use of non-structural carbohydrates.

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Background Traumatic brain injury (TBI) is a leading cause of death and disability that lacks neuroprotective therapies. Following a TBI, secondary injury response pathways are activated and contribute to ongoing neurodegeneration. Microglia and astrocytes are critical neuroimmune modulators with early and persistent reactivity following a TBI. Although histologic glial reactivity is well established, a precise understanding of microglia and astrocyte function following trauma remains unknown. Methods Adult male C57BL/6J mice underwent either fluid percussion or sham injury. RNA sequencing of concurrently isolated microglia and astrocytes was conducted 7 days post-injury to evaluate cell-type-specific transcriptional responses to TBI. Dual in situ hybridization and immunofluorescence were used to validate the TBI-induced gene expression changes in microglia and astrocytes and to identify spatial orientation of cells expressing these genes. Comparative analysis was performed between our glial transcriptomes and those from prior reports in mild TBI and other neurologic diseases to determine if severe TBI induces unique states of microglial and astrocyte activation. Results Our findings revealed sustained, lineage-specific transcriptional changes in both microglia and astrocytes, with microglia showing a greater transcriptional response than astrocytes at this subacute time point. Microglia and astrocytes showed overlapping enrichment for genes related to type I interferon signaling and MHC class I antigen presentation. The microglia and astrocyte transcriptional response to severe TBI was distinct from prior reports in mild TBI and other neurodegenerative and neuroinflammatory diseases. Conclusion Concurrent lineage-specific analysis revealed novel TBI-specific transcriptional changes; these findings highlight the importance of cell-type-specific analysis of glial reactivity following TBI and may assist with the identification of novel, targeted therapies.