• Premise of the study: The filamentous chlorophyte Cladophora produces abundant nearshore populations in marine and freshwaters worldwide, often dominating periphyton communities and producing nuisance growths under eutrophic conditions. High surface area and environmental persistence foster such high functional and taxonomic diversity of epiphytic microfauna and microalgae that Cladophora has been labeled an ecological engineer. We tested the hypotheses that (1) Cladophora supports a structurally and functionally diverse epiphytic prokaryotic microbiota that influences materials cycling and (2) mutualistic host–microbe interactions occur. Because previous molecular sequencing‐based analyses of the microbiota of C. glomerata found as western Lake Michigan beach drift had identified pathogenic associates such as Escherichia coli, we also asked if actively growing lentic C. glomerata harbors known pathogens. • Methods: We used 16S rRNA gene amplicon pyrosequencing to examine the microbiota of C. glomerata of Lake Mendota, Dane, Wisconsin, United States, during the growing season of 2011, at the genus‐ or species‐level to infer functional phenotypes. We used correlative scanning electron and fluorescence microscopy to describe major prokaryotic morphotypes. • Key results: We found microscopic evidence for diverse bacterial morphotypes, and molecular evidence for ca. 100 distinct sequence types classifiable to genus at the 80% confidence level or species at the 96–97% level within nine bacterial phyla, but not E. coli or related human pathogens. • Conclusions: We inferred that bacterial epiphytes of lentic C. glomerata have diverse functions in materials cycling, with traits that indicate the occurrence of mutualistic interactions with the algal host.

Rationale We previously co-localized a quantitative trait locus (QTL) for sensitivity to the locomotor stimulant effect of methamphetamine (MA) with a QTL for expression of casein kinase 1 epsilon (Csnk1-ε) in the nucleus accumbens (NAc). Subsequently, we identified a single nucleotide polymorphism in CSNK1E (rs135745) that was associated with increased sensitivity to the subjective effects of d-amphetamine in healthy human subjects. Based on these results, we hypothesized that differential expression of Csnk1-ε causes differential sensitivity to MA-induced locomotor activity in mice. Objective In the present study, we used PF-670462 (PF), which is a selective inhibitor of Csnk1-ε, to directly evaluate the role of Csnk1-ε in the locomotor response to MA in male C57BL/6J mice. Methods We administered vehicle, PF, MA or MA+PF, either via intraperitoneal injections or bilateral intra-NAc microinjections. We also examined Darpp-32 phosphorylation in mice receiving intraperitoneal injections. Results Intraperitoneal PF (20-40 mg/kg) attenuated the locomotor response to MA (2 mg/kg) without affecting baseline activity. The high dose of PF also significantly inhibited MA-induced phosphorylation of Darpp-32, providing a potential mechanism by which Csnk1-ε contributes to MA-induced locomotor activity. Furthermore, microinjection of PF (5 μg/side) into the NAc completely blocked the locomotor response to MA (2.5 μg/side) without affecting baseline activity. Conclusions These results provide direct evidence that Csnk1-ε is crucial for the locomotor stimulant response to a moderate dose of MA and are consistent with the hypothesis that genetic polymorphisms in Csnk1-ε influence sensitivity to amphetamines in both mice and humans.

Periphyton dominated by the cellulose-rich filamentous green alga Cladophora forms conspicuous growths along rocky marine and freshwater shorelines worldwide, providing habitat for diverse epibionts. Bacterial epibionts have been inferred to display diverse functions of biogeochemical significance: N-fixation and other redox reactions, phosphorus accumulation, and organic degradation. Here, we report taxonomic diversity of eukaryotic and prokaryotic epibionts and diversity of genes associated with materials cycling in a Cladophora metagenome sampled from Lake Mendota, Dane Co., WI, USA, during the growing season of 2012. A total of 1,060 distinct 16S, 173 18S, and 351 28S rRNA operational taxonomic units, from which >220 genera or species of bacteria (~60), protists (~80), fungi (6), and microscopic metazoa (~80), were distinguished with the use of reference databases. We inferred the presence of several algal taxa generally associated with marine systems and detected Jaoa, a freshwater periphytic ulvophyte previously thought endemic to China. We identified six distinct nifH gene sequences marking nitrogen fixation, >25 bacterial and eukaryotic cellulases relevant to sedimentary C-cycling and technological applications, and genes encoding enzymes in aerobic and anaerobic pathways for vitamin B12 biosynthesis. These results emphasize the importance of Cladophora in providing habitat for microscopic metazoa, fungi, protists, and bacteria that are often inconspicuous, yet play important roles in ecosystem biogeochemistry.

In the setting of radiation-induced trauma, exposure to high levels of radiation can cause an acute radiation syndrome (ARS) causing bone marrow (BM) failure, leading to life-threatening infections, anemia, and thrombocytopenia. We have previously shown that human macrophages educated with human mesenchymal stem cells (MSCs) by coculture can significantly enhance survival of mice exposed to lethal irradiation. In this study, we investigated whether exosomes isolated from MSCs could replace direct coculture with MSCs to generate exosome educated macrophages (EEMs). Functionally unique phenotypes were observed by educating macrophages with exosomes from MSCs (EEMs) primed with bacterial lipopolysaccharide (LPS) at different concentrations (LPS-low EEMs or LPS-high EEMs). LPS-high EEMs were significantly more effective than uneducated macrophages, MSCs, EEMs, or LPS-low EEMs in extending survival after lethal ARS in vivo. Moreover, LPS-high EEMs significantly reduced clinical signs of radiation injury and restored hematopoietic tissue in the BM and spleen as determined by complete blood counts and histology. LPS-high EEMs showed significant increases in gene expression of STAT3, secretion of cytokines like IL-10 and IL-15, and production of growth factors like FLT-3L. LPS-EEMs also showed increased phagocytic activity, which may aid with tissue remodeling. LPS-high EEMs have the potential to be an effective cellular therapy for the management of ARS.

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