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The Greater Everglades Ecosystem is a globally important ecoregion, home to 68 threatened or endangered species and the largest designated wilderness area in the Eastern United States. Anthropogenic manipulations of the natural hydrology have led to widespread degradation of this ecosystem and monitored population declines across multiple taxa. Simultaneous introductions of hundreds of non-native species into South Florida and their subsequent invasion into the Everglades has further impacted native Everglades communities. Predictions for future climate change suggest that the Everglades is headed towards a drier future, making it crucial to understand how changes in hydrological regimes will impact both native and non-native fauna. Our study combines the results of a landscape-scale experimental manipulation conducted to assess the impact of differing hydrological regimes at the Loxahatchee Impoundment Landscape Assessment between 2018 and 2020 with a community composition analysis of data collected across multiple habitat types throughout Everglades National Park between 2000 and 2002. Both datasets used a variety of survey methods to extensively characterize the amphibian and reptile amphibian assemblage across habitat types and hydrological regimes. An NMDS analysis indicated that variation in hydrology is the primary axis structuring reptile and amphibian habitat usage across the Everglades, with non-native species more likely to be indicators of drier habitat types. This result concurred with those from the landscape-scale manipulation, in which non-native species were significantly favored by drier hydrological conditions. Taken together, these results suggest that a drier future within the Greater Everglades Ecosystem may facilitate further spread of South Florida’s diverse non-native amphibian and reptile assemblage.

Predicting ecological effects of contaminants remains challenging because of the sheer number of chemicals and their ambiguous role in biodiversity-ecosystem function relationships. We evaluate responses of experimental pond ecosystems to standardized concentrations of 12 pesticides, nested in four pesticide classes and two pesticide types. We show consistent effects of herbicides and insecticides on ecosystem function, and slightly less consistent effects on community composition. Effects of pesticides on ecosystem function are mediated by alterations in the abundance and community composition of functional groups. Through bottom-up effects, herbicides reduce respiration and primary productivity by decreasing the abundance of phytoplankton. The effects of insecticides on respiration and primary productivity of phytoplankton are driven by top-down effects on zooplankton composition and abundance, but not richness. By demonstrating consistent effects of pesticides on communities and ecosystem functions and linking pesticide-induced changes in functional groups of organisms to ecosystem functions, the study suggests that ecological risk assessment of registered chemicals could be simplified to synthetic chemical classes or types and groups of organisms with similar functions and chemical toxicities., The effects of pesticides on individual species could propagate into additional community-wide and ecosystem-level effects. Here the authors use a mesocosm experiment to test how a diverse array of herbicides and insecticides disrupt aquatic community structure and ecosystem function.

The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 disease, has killed over five million people worldwide as of December 2021 with infections rising again due to the emergence of highly transmissible variants. Animal models that faithfully recapitulate human disease are critical for assessing SARS-CoV-2 viral and immune dynamics, for understanding mechanisms of disease, and for testing vaccines and therapeutics. Pigtail macaques (PTM, Macaca nemestrina) demonstrate a rapid and severe disease course when infected with simian immunodeficiency virus (SIV), including the development of severe cardiovascular symptoms that are pertinent to COVID-19 manifestations in humans. We thus proposed this species may likewise exhibit severe COVID-19 disease upon infection with SARS-CoV-2. Here, we extensively studied a cohort of SARS-CoV-2-infected PTM euthanized either 6- or 21-days after respiratory viral challenge. We show that PTM demonstrate largely mild-to-moderate COVID-19 disease. Pulmonary infiltrates were dominated by T cells, including CD4+ T cells that upregulate CD8 and express cytotoxic molecules, as well as virus-targeting T cells that were predominantly CD4+. We also noted increases in inflammatory and coagulation markers in blood, pulmonary pathologic lesions, and the development of neutralizing antibodies. Together, our data demonstrate that SARS-CoV-2 infection of PTM recapitulates important features of COVID-19 and reveals new immune and viral dynamics and thus may serve as a useful animal model for studying pathogenesis and testing vaccines and therapeutics., Author summary The COVID-19 pandemic has claimed the lives of millions in a span of less than two years. Despite the development of several highly effective vaccines, many millions remain unvaccinated, and several highly transmissible variants have emerged, clearly suggesting the need for new approaches to treat those that become severely ill. The development of new drugs will rely on having animal models that reproduce the most severe disease seen in humans. To date, nonhuman primate models have not exhibited this severe disease. In this study we tested whether pigtail macaques (PTM) might exhibit such severe disease, based on previous work showing this species is prone to more rapid and severe disease when infected with other viruses.

Mitochondrial function is critical in eukaryotes. To maintain an adequate supply of energy, precise interactions must be maintained between nuclear- and mitochondrial-encoded gene products. Such interactions are paramount in chimeric enzymes such as the oxidative phosphorylation (OXPHOS) complexes. Mutualistic coevolution between the two genomes has therefore been suggested to be a critical, ubiquitous feature of eukaryotes that acts to maintain cellular function. However, mitochondrial genomes can also act selfishly and increase their own transmission at the expense of organismal function. For example, male-harming mutations are predisposed to accumulate in mitochondrial genomes due to their maternal inheritance (“mother’s curse”). Here, we investigate sexually antagonistic mitonuclear coevolution in nuclear-encoded OXPHOS paralogs from mammals and Drosophila. These duplicate genes are highly divergent but must interact with the same set of mitochondrial-encoded genes. Many such paralogs show testis-specific expression, prompting previous hypotheses suggesting they may have evolved under selection to counteract male-harming mitochondrial mutations. We found increased rates of evolution in OXPHOS paralogs with testis-specific expression in mammals and Drosophila, supporting this hypothesis. However, further analyses suggested such patterns may be due to relaxed, not positive selection, especially in Drosophila. Structural data also suggest that mitonuclear interactions do not play a major role in the evolution of many OXPHOS paralogs in a consistent way. In conclusion, no single OXPHOS paralog met all our criteria for being under selection to counteract male-harming mitochondrial mutations. We discuss alternative explanations for the drastic patterns of evolution in these genes, including mutualistic mitonuclear coevolution, adaptive subfunctionalization after gene duplication, and relaxed selection on OXPHOS in male tissues.

Mitonuclear coevolution is an important prerequisite for efficient energy production in eukaryotes. However, many bivalve taxa experience doubly uniparental inheritance (DUI) and have sex-specific mitochondrial (mt) genomes, providing a challenge for mitonuclear coevolution. We examined possible mechanisms to reconcile mitonuclear coevolution with DUI. No nuclear-encoded, sex-specific OXPHOS paralogs were found in the DUI clam Ruditapes philippinarum, refuting OXPHOS paralogy as a solution in this species. It is also unlikely that mt changes causing disruption of nuclear interactions are strongly selected against because sex-specific mt-residues or those under positive selection in M mt genes were not depleted for contacting nuclear-encoded residues. However, M genomes showed consistently higher d(N)/d(S) ratios compared to putatively ancestral F genomes in all mt OXPHOS genes and across all DUI species. Further analyses indicated that this was consistently due to relaxed, not positive selection on M vs. F mt OXPHOS genes. Similarly, selection was relaxed on the F genome of DUI species compared to species with strict maternal inheritance. Coupled with recent physiological and molecular evolution studies, we suggest that relaxed selection on M mt function limits the need to maintain mitonuclear interactions in M genomes compared to F genomes. We discuss our findings with regard to OXPHOS function and the origin of DUI.

Among its many impacts, climate warming is leading to increasing winter air temperatures, decreasing ice cover extent, and changing winter precipitation patterns over the Laurentian Great Lakes and their watershed. Understanding and predicting the consequences of these changes is impeded by a shortage of winter-period studies on most aspects of Great Lake limnology. In this review, we summarize what is known about the Great Lakes during their 3–6 months of winter and identify key open questions about the physics, chemistry, and biology of the Laurentian Great Lakes and other large, seasonally frozen lakes. Existing studies show that winter conditions have important effects on physical, biogeochemical, and biological processes, not only during winter but in subsequent seasons as well. Ice cover, the extent of which fluctuates dramatically among years and the five lakes, emerges as a key variable that controls many aspects of the functioning of the Great Lakes ecosystem. Studies on the properties and formation of Great Lakes ice, its effect on vertical and horizontal mixing, light conditions, and biota, along with winter measurements of fundamental state and rate parameters in the lakes and their watersheds are needed to close the winter knowledge gap. Overcoming the formidable logistical challenges of winter research on these large and dynamic ecosystems may require investment in new, specialized research infrastructure. Perhaps more importantly, it will demand broader recognition of the value of such work and collaboration between physicists, geochemists, and biologists working on the world's seasonally freezing lakes and seas.

Understanding which fungi exhibit certain ecological traits, such as habitat, host, or substrate associations, and knowing how these traits change across space and time can provide invaluable insight into the roles fungi play in their respective ecosystems. Archived sporocarp data, such as the collection and observation records accessible through the Mycology Collections Portal (MyCoPortal), are well suited for trait investigations, since these records circumvent the need for field work, are geographically and temporally diverse, and often have detailed and trait-relevant environmental metadata. However, there are inefficiencies and inadequacies in the MyCoPortal online interface that affect data set generation and trait searching, and many of the available records have outdated or misspelled taxon names as well as misspelled location names. Thus, we created the r package fungarium, which enables the efficient download of complete MyCoPortal data sets from within the R environment, enhances the identification of trait-relevant records, confirms or updates taxon names while also accounting for spelling errors, and fixes misspelled location names. Utilizing this package and MyCoPortal data, we demonstrated methods for analyzing taxonomic, geographic, and temporal patterns in ecological traits, using fire association as an example. We found that fire association, which was quantified via fire-associated enrichment factors (fire-associated records/total records), differed substantially between taxa, and these differences were qualitatively supported by existing literature, as hypothesized. Sampling bias within the MyCoPortal data and limitations of the burned acreage data set used (i.e., Monitoring Trends in Burn Severity) were identified as confounding factors in our geographic and temporal analyses, as evidenced by the unexpected lack of correlation between fire association and burned acreage on county and year bases. However, both confounding factors likely depend on the trait analyzed and external data set used. Overall, the fungarium package and associated methods presented here effectively enable the use of archived sporocarp data for future ecological trait studies.

Summary Pericytes play a critical role in promoting, regulating, and maintaining numerous vascular functions. Their dysfunction is a major contributor to the progression of vascular and neurodegenerative diseases, making them an ideal candidate for large-scale production for disease modeling and regenerative cell therapy. This protocol describes the rapid and robust differentiation of pericytes from human induced pluripotent stem cells (hiPSCs) while simultaneously generating a population of hiPSC-derived endothelial progenitor cells. For complete details on the use and execution of this protocol, please refer to Zhang et al. (2017)., Graphical abstract, Highlights • Generate pericytes from hiPSCs using magnetic cell sorting • Simultaneously generate a population of hiPSC-derived endothelial progenitor cells • Characterize pericytes via flow cytometry, immunofluorescence, and functional assays, Pericytes play a critical role in promoting, regulating, and maintaining numerous vascular functions. Their dysfunction is a major contributor to the progression of vascular and neurodegenerative diseases, making them an ideal candidate for large-scale production for disease modeling and regenerative cell therapy. This protocol describes the rapid and robust differentiation of pericytes from human induced pluripotent stem cells (hiPSCs) while simultaneously generating a population of hiPSC-derived endothelial progenitor cells.

BACKGROUND: The cholesteryl ester transfer protein inhibitor evacetrapib substantially raises the high-density lipoprotein (HDL) cholesterol level, reduces the low-density lipoprotein (LDL) cholesterol level, and enhances cellular cholesterol efflux capacity. We sought to determine the effect of evacetrapib on major adverse cardiovascular outcomes in patients with high-risk vascular disease. METHODS: In a multicenter, randomized, double-blind, placebo-controlled phase 3 trial, we enrolled 12,092 patients who had at least one of the following conditions: an acute coronary syndrome within the previous 30 to 365 days, cerebrovascular atherosclerotic disease, peripheral vascular arterial disease, or diabetes mellitus with coronary artery disease. Patients were randomly assigned to receive either evacetrapib at a dose of 130 mg or matching placebo, administered daily, in addition to standard medical therapy. The primary efficacy end point was the first occurrence of any component of the composite of death from cardiovascular causes, myocardial infarction, stroke, coronary revascularization, or hospitalization for unstable angina. RESULTS: At 3 months, a 31.1% decrease in the mean LDL cholesterol level was observed with evacetrapib versus a 6.0% increase with placebo, and a 133.2% increase in the mean HDL cholesterol level was seen with evacetrapib versus a 1.6% increase with placebo. After 1363 of the planned 1670 primary end-point events had occurred, the data and safety monitoring board recommended that the trial be terminated early because of a lack of efficacy. After a median of 26 months of evacetrapib or placebo, a primary end-point event occurred in 12.9% of the patients in the evacetrapib group and in 12.8% of those in the placebo group (hazard ratio, 1.01; 95% confidence interval, 0.91 to 1.11; P=0.91). CONCLUSIONS: Although the cholesteryl ester transfer protein inhibitor evacetrapib had favorable effects on established lipid biomarkers, treatment with evacetrapib did not result in a lower rate of cardiovascular events than placebo among patients with high-risk vascular disease. (Funded by Eli Lilly; ACCELERATE ClinicalTrials.gov number, NCT01687998 .).

Streptococcus pyogenes or group A Streptococcus (GAS) is a leading cause of bacterial pharyngitis, skin and soft tissue infections, life-threatening invasive infections, and the post-infectious autoimmune syndromes of acute rheumatic fever and post-streptococcal glomerulonephritis. Genetic manipulation of this important pathogen is complicated by resistance of the organism to genetic transformation. Very low transformation efficiency is attributed to recognition and degradation of introduced foreign DNA by a type I restriction-modification system encoded by the hsdRSM locus. DNA sequence analysis of this locus in ten GAS strains that had been previously transformed with an unrelated plasmid revealed that six of the ten harbored a spontaneous mutation in hsdR, S, or M. The mutations were all different, and at least five of the six were predicted to result in loss of function of the respective hsd gene product. The unexpected occurrence of such mutations in previously transformed isolates suggested that the process of transformation selects for spontaneous inactivating mutations in the Hsd system. We investigated the possibility of exploiting the increased transformability of hsd mutants by constructing a deletion mutation in hsdM in GAS strain 854, a clinical isolate representative of the globally dominant M1T1 clonal group. Mutant strain 854ΔhsdM exhibited a 5-fold increase in electrotransformation efficiency compared to the wild type parent strain and no obvious change in growth or off-target gene expression. We conclude that genetic transformation of GAS selects for spontaneous mutants in the hsdRSM restriction modification system. We propose that use of a defined hsdM mutant as a parent strain for genetic manipulation of GAS will enhance transformation efficiency and reduce the likelihood of selecting spontaneous hsd mutants with uncharacterized genotypes.

Current predictions of the effects of synthetic chemicals on freshwater ecosystems are hampered by the sheer number of chemical contaminants entering aquatic systems, the diversity of organisms inhabiting these systems, and uncertainties about how contaminants alter ecosystem metabolism. We conducted a mesocosm experiment that elucidated the responses of ponds composed of phytoplankton and zooplankton to standardized concentrations of 12 pesticides, nested within four pesticide classes and two pesticide types. We show that the effects of the pesticides on algae were consistent within herbicides and insecticides and responses of over 70 phytoplankton species and genera were consistent within broad taxonomic groups. Insecticides generated top-down effects on phytoplankton community composition and abundance, which were associated with persistent increases in ecosystem respiration. Herbicides reduced phytoplankton abundance, which was associated with decreases in primary productivity and ecosystem respiration. These results suggest that widespread pesticide use could have underexplored implications for the global carbon cycle. While these effects on ecosystem respiration were mediated through complex effects on communities, taxonomic groups of organisms responded similarly to pesticide types, suggesting opportunities to simplify ecological risk assessment.

Adenovirus (Ad) infections are usually mild and self-limited, with minimal inflammatory responses. During worldwide outbreaks, Ad14p1, an emerging Ad14 variant, has caused severe pulmonary disease, including acute respiratory distress syndrome (ARDS). This increased pathogenicity of Ad14p1 is not completely understood. In initial studies, we observed that infection of Syrian hamsters with Ad14p1 can cause a patchy bronchopneumonia, with an increased intensity of inflammation, compared to wild type Ad14 infection. The current study compared the dynamics of the immunopathogenesis of Ad14 and Ad14p1 infection of hamster lungs through the first two weeks after infection. Little difference was seen in infection-induced inflammation at day 1. Beginning at day 3, Ad14p1-infected hamsters showed marked inflammation that continued through to day 7. The inflammation began to resolve by day 10 but was still detectable at day 14. In contrast, Ad14-infected hamsters showed little inflammation during the 14-day period of observation. Inflammatory cell type analysis revealed that, at day 1, hamsters infected with either virus had predominantly neutrophil infiltration that began to resolve by day 3. However, at day 5, Ad14p1-infected hamsters had a second wave of neutrophil infiltration that was accompanied by edema which persisted to a variable extent through to day 10. These differences were not explained by an increased Ad14p1 replication rate, compared with Ad14 in vitro, but there was prolonged persistence of Ad14p1 in hamster lungs. There were differences in lung tissue cytokine and chemokine responses to Ad14p1 vs. Ad14 infection that might account for the increased leukocyte infiltrates in Ad14p1-infected hamsters. This animal model characterization provides the basis for future translational studies of the viral genetic mechanisms that control the increased immunopathogenesis of the emergent, Ad14p1 strain.

The use of plastral scute rings to age turtles is a widely practiced technique, but a lack of rigorous field testing of this method has led to critiques of its usefulness and accuracy. We tested the method's effectiveness for aging spotted turtles (Clemmys guttata) by calculating an Age-Increase Ratio and by recording changes in the number of scutes within a year. We found no correlation between the change in the number of scute rings and the number of years between captures, which likely stems from the observer error associated with the difficulty of accurately counting scutes on older turtles; however, we did record a significant correlation between the number of scute rings and body size.

Background Increased peak external knee adduction moments exist for individuals with knee osteoarthritis and varus knee alignments, compared to healthy and neutrally aligned counterparts. Walking with increased toe-in or increased step width have been individually utilized to successfully reduce 1st and 2nd peak knee adduction moments, respectfully, but have not previously been combined or tested among all alignment groups. The purpose of this study was to compare toe-in only and toe-in with wider step width gait modifications in individuals with neutral, valgus, and varus alignments. Methods Thirty-eight healthy participants with confirmed varus, neutral, or valgus frontal-plane knee alignment through anteroposterior radiographs, performed level walking in normal, toe-in, and toe-in with wider step width gaits. A 3 × 3 (group × intervention) mixed model repeated measures ANOVA compared alignment groups and gait interventions (p Results The 1st peak knee adduction moment was reduced in both toe-in and toe-in with wider step width compared to normal gait. The 2nd peak adduction moment was increased in toe-in compared to normal and toe-in with wider step width. The adduction impulse was also reduced in toe-in and toe-in with wider step width compared to normal gait. Peak knee flexion and external rotation moments were increased in toe-in and toe-in with wider step width compared to normal gait. Conclusion Although the toe-in with wider step width gait seems to be a viable option to reduce peak adduction moments for varus alignments, sagittal, and transverse knee loadings should be monitored when implementing this gait modification strategy.

In clinical practice, delays in obtaining culture results impact patient care and the ability to tailor antibiotic therapy. Despite the advancement of rapid molecular diagnostics, the use of plate cultures inoculated from swab samples continues to be the standard practice in clinical care. Because the inoculation culture process can take between 24 and 48h before a positive identification test can be run, there is an unmet need to develop rapid throughput methods for bacterial identification. Previous work has shown that pyocyanin can be used as a rapid, redox-active biomarker for identifying Pseudomonas aeruginosa in clinical infections. However, further validation is needed to confirm pyocyanin production occurs in all clinical strains of P. aeruginosa. Here, we validate this electrochemical detection strategy using clinical isolates obtained from patients with hospital-acquired infections or with cystic fibrosis. Square-wave voltammetric scans of 94 different clinical P. aeruginosa isolates were taken to measure the concentration of pyocyanin. The results showed that all isolates produced measureable concentrations of pyocyanin with production rates correlated with patient symptoms and comorbidity. Further bioinformatics analysis confirmed that 1649 genetically sequenced strains (99.9%) of P. aeruginosa possess the two genes (PhzM and PhzS) necessary to produce pyocyanin, supporting the specificity of this biomarker. Confirming the production of pyocyanin by all clinically-relevant strains of P. aeruginosa is a significant step towards validating this strategy for rapid, point-of-care diagnostics.

P availability often limits primary production in freshwater ecosystems and excessive P inputs promote accelerated eutrophication. Microbial mechanisms may control O2-dependent uptake/release of P in stream sediments and biofilms, but specific organisms responsible for these cycles have not been identified. Polyphosphate accumulating organisms (PAOs) are purposely enriched in treatment plants to remove P from wastewater. PAOs release P under anaerobic conditions and take it up under aerobic conditions. We hypothesized that alternating aerobic/anaerobic conditions promote patterns of P uptake/release similar to those attributed to PAOs in wastewater treatment. We collected intact, native stream biofilms and subjected them to laboratory treatments to impose conditions similar to what may occur because of diel oxygenic and respiratory cycles: 1) continuous sparging with air and 2) alternate sparging with air or anaerobic gas (20∶80% by volume CO2∶N2). We monitored PO43−, Ca, Mg, total Mn, K, Fe2+, an...

A gap in our understanding of phytoplankton seasonality in temperate lakes exists mainly due to the lack of information collected during the winter months. We summarized seasonal changes of phytoplankton biomass and taxonomic composition relative to water-column biogeochemical conditions in 6 lakes located on Beaver Island and 1 site in Lake Michigan in close geographic proximity to each other (

Re-eutrophication and harmful algal blooms in Lake Erie have resulted in a renewed call for remedial measures such as reductions of phosphorus loads to the lake's western basin. The action of further nutrient reductions may also reduce the intensity of seasonal central basin hypolimnetic anoxia by reducing algal biomass. However, winter–spring blooms of diatoms have not been fully recognized as a source of algal biomass that might contribute significantly to summer hypoxia. We compared spring and summer phytoplankton abundance in central and western Lake Erie based on monitoring data to show that spring phytoplankton biovolume was 1.5- to 6-fold greater than summer biovolume and that most spring biovolume was composed of filamentous diatoms, primarily Aulacoseira islandica , that is likely supported by an increasing silica load from Lake Huron. The rise of silica export was attributed to the dreissenid mussel invasion and establishment that reduced diatom abundance in Lake Huron and thereby increased silica availability in the receiving water body of Lake Erie. The relationship between phosphorus and winter–spring diatom blooms was unclear, but diatoms probably contributed the majority of the algal biomass that accumulated annually in the hypolimnion of the central basin of Lake Erie. Remedial measures aimed at reducing hypoxia must consider the winter–spring phytoplankton bloom in Lake Erie as an important and reoccurring feature of the lake that delivers a considerable quantity of algal biomass to the profundal zone of the lake.

In clinical practice, point-of-care diagnostic testing has progressed rapidly in the last decade. For the field of wound care, there is a compelling need to develop rapid alternatives for bacterial identification in the clinical setting, where it generally takes over 24 hours to receive a positive identification. Even new molecular and biochemical identification methods require an initial incubation period of several hours to obtain a sufficient number of cells prior to performing the analysis. Here we report the use of an inexpensive, disposable electrochemical sensor to detect pyocyanin, a unique, redox-active quorum sensing molecule released by Pseudomonas aeruginosa, in wound fluid from patients with chronic wounds enrolled in the WE-HEAL Study. By measuring the metabolite excreted by the cells, this electrochemical detection strategy eliminates sample preparation, takes less than a minute to complete, and requires only 7.5 μL of sample to complete the analysis. The electrochemical results were compared against 16S rRNA profiling using 454 pyrosequencing. Blind identification yielded 9 correct matches, 2 false negatives, and 3 false positives giving a sensitivity of 71% and specificity of 57% for detection of Pseudomonas. Ongoing enhancement and development of this approach with a view to develop a rapid point-of-care diagnostic tool is planned.

The use of ecological niche models to predict how future climate change may impact habitat suitability is a critical component of imperiled species management. These models allow for the identification of areas with high future suitability that will support the persistence of the species. We developed an ecological niche model and performed protected areas analysis to assess the current and future distribution of suitable habitat for the globally endangered wood turtle (Glyptemys insculpta) across the northeastern U.S. portion of its range. Our model predicts that by 2070 the suitable habitat for this species will decrease by 29–52%, and the total area of optimal habitat will decrease by 62–86%, depending on emissions scenario. Furthermore, currently only 5% of suitable habitat and 8% of optimal habitat is protected, with the total area of protected suitable and optimal habitat expected to decrease by 16–28% and 31–64%, respectively, by 2070. Our results suggest that long-term wood turtle conservation efforts should be directed towards protecting habitat in higher latitudes of their range, mainly in the states of Maine, Vermont, New Hampshire, and New York where the majority of climate refugia exist. Additionally, management action will be required to facilitate the northward transition of southern populations that are threatened with extinction due to rising temperatures. Along with having important conservation implications for the imperiled wood turtle, our study also serves as an example of how climate change assessments should be used to direct long-term conservation efforts of other imperiled species across the globe.

Pesticide pollution can alter parasite transmission, but scientists are unaware if effects of pesticides on parasite exposure and host susceptibility (i.e. infection risk given exposure) can be generalised within a community context. Using replicated temperate pond communities, we evaluate effects of 12 pesticides, nested in four pesticide classes (chloroacetanilides, triazines, carbamates organophosphates) and two pesticide types (herbicides, insecticides) applied at standardised environmental concentrations on larval amphibian exposure and susceptibility to trematode parasites. Most of the variation in exposure and susceptibility occurred at the level of pesticide class and type, not individual compounds. The organophosphate class of insecticides increased snail abundance (first intermediate host) and thus trematode exposure by increasing mortality of snail predators (top-down mechanism). While a similar pattern in snail abundance and trematode exposure was observed with triazine herbicides, this effect was driven by increases in snail resources (periphytic algae, bottom-up mechanism). Additionally, herbicides indirectly increased host susceptibility and trematode infections by (1) increasing time spent in susceptible early developmental stages and (2) suppressing tadpole immunity. Understanding generalisable effects associated with contaminant class and type on transmission is critical in reducing complexities in predicting disease dynamics in at-risk host populations.

α-Synuclein (α-syn) is an abundant presynaptic protein that is the primary constituent of inclusions that define Lewy body diseases (LBDs). In these inclusions, α-syn is phosphorylated at the serine-129 residue. Antibodies directed to this phosphorylation site are used to measure inclusion abundance and stage disease progression in pre-clinical models as well as in post-mortem tissues in LBDs. While it is critical to reliably identify inclusions, phospho-specific antibodies often cross-react with non-specific antigens. Four commercially available monoclonal antibodies, two from rabbits (clones EP1536Y and MJF-R13) and two from mice (81a and pSyn#64), have been the most widely used in detecting pS129-α-syn inclusions. Here, we systematically evaluated these antibodies in brain sections and protein lysates from rats and mice. All antibodies detected pS129-α-syn inclusions in the brain that were induced by preformed α-syn fibrils in wild-type rats and mice. Antibody titrations revealed that clones EP1536Y and 81a comparably labeled inclusions in both the perikarya and neuronal processes in contrast to clones MJF-R13 and pSyn#64 that incompletely labeled inclusions at various antibody concentrations. Except for EP1536Y, the clones produced non-specific diffuse neuropil labeling in α-syn knockout mice as well as mice and rats injected with monomeric α-syn, with some non-specific staining titrating with pS129-α-syn inclusions. By immunoblot, all the clones cross-reacted with proteins other than α-syn, warranting caution in interpretations of specificity. Clone EP1536Y uniquely and robustly detected endogenous pS129-α-syn in highly soluble protein fractions from the mouse brain. In summary, EP1536Y had the highest sensitivity and specificity for detecting pS129-α-syn.

Microbiological, genomic and transcriptomic analyses were used to examine three species from the bacterial genus Caldicellulosiruptor with respect to their capacity to convert the carbohydrate content of lignocellulosic biomass at 70°C to simple sugars, acetate, lactate, CO 2 , and H 2 . Caldicellulosiruptor bescii , C. kronotskyensis , and C. saccharolyticus solubilized 38%, 36%, and 29% (by weight) of unpretreated switchgrass ( Panicum virgatum ) (5 g/liter), respectively, which was about half of the amount of crystalline cellulose (Avicel; 5 g/liter) that was solubilized under the same conditions. The lower yields with C. saccharolyticus , not appreciably greater than the thermal control for switchgrass, were unexpected, given that its genome encodes the same glycoside hydrolase 9 (GH9)-GH48 multidomain cellulase (CelA) found in the other two species. However, the genome of C. saccharolyticus lacks two other cellulases with GH48 domains, which could be responsible for its lower levels of solubilization. Transcriptomes for growth of each species comparing cellulose to switchgrass showed that many carbohydrate ABC transporters and multidomain extracellular glycoside hydrolases were differentially regulated, reflecting the heterogeneity of lignocellulose. However, significant differences in transcription levels for conserved genes among the three species were noted, indicating unexpectedly diverse regulatory strategies for deconstruction for these closely related bacteria. Genes encoding the Che-type chemotaxis system and flagellum biosynthesis were upregulated in C. kronotskyensis and C. bescii during growth on cellulose, implicating motility in substrate utilization. The results here show that capacity for plant biomass deconstruction varies across Caldicellulosiruptor species and depends in a complex way on GH genome inventory, substrate composition, and gene regulation.

The Lake Michigan ecosystem has undergone numerous, systemic changes (reduced nutrient, changing climate, invasive mussels) that have altered portions of the food web and thus, appear to have changed the lake's trophic state. That said, little is known about the components of the microbial food web (MFW, heterotrophic and phototrophic pico, nano, and micro-plankton), which we hypothesized have compensated as a food source for crustacean zooplankton given the recent declines in the biomass of large phytoplankton (mainly diatoms). Therefore, we measured the abundance of the entire MFW using complementary microscopic techniques, flow cytometry, and size fractionated chlorophyll concentrations at sites in northern and southern Lake Michigan, and one site in Lake Superior; the latter site served as a benchmark for oligotrophic conditions. In addition, a historic comparison was made between 1987 and 2013 for the southern Lake Michigan site. Ppico numbers (i.e., picocyanobacteria) in 2013 were lower compared with those in the 1980s; however, the percent contribution of the 50% of total chlorophyll). The abundance of small, pigmented chrysomonads and cryptomonads (Pnano size category) was not significantly different between 1987 and 2013 at the same time Pmicro did decline; this shift towards Ppico and Pnano dominance may be related to the recent oligotrophication of Lake Michigan. The abundance of ciliated protists (Hmicro size class) was 3-fold lower in 2013 compared with levels in 1987, while the abundance of both Hpico (eubacteria, range 0.24–1.36 × 10 6 cells mL − 1 ) and Hnano (mainly colorless chrysomonads; range 0.11–6.4 × 10 3 cells mL − 1 ) remained stable and reflected the resilience of bacteria–flagellate trophic linkage.

Picoplankton often regulate the trophic dynamics and key biogeochemical cycles in pelagic environments That said comparatively little I known about their seasonal contribution to carbon cycling in Lake Superior one of the largest lakes world wide where attempts to reconcile the carbon and N budgets have not been straightforward Here we presented some of few seasonal estimates for both heterotrophic Hpico and phototrophic Ppico picoplankton abundance biomass and morphological diversity in Lake Superior n Seasonal samples were collected at two offshore stations in the central basin of Lake Superior on six cruises conducted at monthly intervals May October Fractionated chlorophyll analysis revealed that algae in the micro m size category nanoplankton constituted gt of the assemblage while the Ppico size fraction constituted total chlorophyll lt micro g bull L The Hpico assemblage was dominated by simply cocci forms i e eubacteria Hpico abundance ranged from to x nbsp cells bull mL and on average supported fold greater numbers compared with the abundance of Ppico to x nbsp cells bull mL Ppico was dominated by phycoerythrin rich single celled taxa whose abundance was relatively constant from May September The concentration of chlorophyll Hpico bacteria and pico eukaryotes increased with mixing depth however chlorophyll and Ppico numbers exhibited a fold increase in October when bacterial numbers were at their lowest level Despite these differences in seasonal dynamics overall carbon estimates for both Hpico and Ppico were comparable and collectively constituted a substantial faction of plankton carbon in the lake mean and micro gC bull L respectively indicating their importance in reconciling the carbon budget for LakeSuperior

Static frontal plane tibiofemoral alignment is an important factor in dynamic knee alignment and knee adduction moments. However, little is known about the relationship between alignment and compartment contact forces or muscle control strategies. The purpose of this study was to estimate medial (MCF) and lateral (LCF) compartment knee joint contact forces and muscle forces during stair ascent using a musculoskeletal model implementing subject specific knee alignments. Kinematic and kinetic data from 20 healthy individuals with radiographically confirmed varus or valgus knee alignments were simulated using alignment specific models to predict MCFs and LCFs. Muscle forces were determined using static optimization. Independent samples t-tests compared contact and knee and frontal plane hip muscle forces between groups during weight acceptance and during pushoff. The varus group exhibited increased weight acceptance peak MCFs, while the valgus group exhibited increased pushoff peak LCFs. The varus group utilized increased vasti muscle forces during weight acceptance and hip adductor forces during pushoff. The valgus group utilized increased hip abductor forces during pushoff. The alignment dependent contact forces provide evidence of the significance of frontal plane knee alignment in healthy individuals, which may be important in considering future knee joint health. The differing muscle control strategies between alignments detail specific neuromuscular responses to control frontal plane knee loads.

BACKGROUND Autosomal dominant polycystic kidney disease is the most common monogenetic kidney disorder and is linked to mutations in PKD1 and PKD2. PKD2, a Ca2+ -conducting TRP channel enriched in ciliated cells and gated by extracellular signals, is necessary to activate the multifunctional Ca2+/ calmodulin-dependent protein kinase type 2 (CaMK-II), enabling kidney morphogenesis and cilia stability. RESULTS In this study, antisense morpholino oligonucleotides and pharmacological compounds were employed to investigate the roles of class II HDAC family members (HDAC 4, 5, and 6) in Zebrafish kidney development. While all three class II HDAC genes were expressed throughout the embryo during early development, HDAC5-morphant embryos exhibited anterior cysts and destabilized cloacal cilia, similar to PKD2 and CaMK-II morphants. In contrast, HDAC4-morphant embryos exhibited elongated cloacal cilia and lacked anterior kidney defects. Suppression of HDAC4 partially reversed the cilia shortening and anterior convolution defects caused by CaMK-II deficiency, whereas HDAC5 loss exacerbated these defects. EGFP-HDAC4, but not EGFP-HDAC5, translocated into the nucleus upon CaMK-II suppression in pronephric kidney cells. CONCLUSIONS These results support a model by which activated CaMK-II sequesters HDAC4 in the cytosol to enable primary cilia formation and kidney morphogenesis. Developmental Dynamics 247:807-817, 2018. © 2018 Wiley Periodicals, Inc.

Freshwater bacteria play fundamental roles in global elemental cycling and are an intrinsic part of local food webs. Human activities are altering freshwater environments, and much has been learned regarding the sensitivity of bacterial assemblages to a variety of these disturbances. Yet, relatively few studies have focused on how species invasion, which is one of the most important aspects of anthropogenic global change, affects freshwater bacterial assemblages. This study focuses on the impact of invasive dreissenid mussels (IDMs), a globally distributed group of invasive species with large impacts on freshwater phyto- and zooplankton assemblages. We show that IDMs have direct effects on lake bacterioplankton abundance, taxonomic composition, and inferred bacterial functional group representation., One approach to improve forecasts of how global change will affect ecosystem processes is to better understand how anthropogenic disturbances alter bacterial assemblages that drive biogeochemical cycles. Species invasions are important contributors to global change, but their impacts on bacterial community ecology are rarely investigated. Here, we studied direct impacts of invasive dreissenid mussels (IDMs), one of many invasive filter feeders, on freshwater lake bacterioplankton. We demonstrated that direct effects of IDMs reduced bacterial abundance and altered assemblage composition by preferentially removing larger and particle-associated bacteria. While this increased the relative abundances of many free-living bacterial taxa, some were susceptible to filter feeding, in line with efficient removal of phytoplankton cells of

Cyanobacterial harmful algal blooms (CyanoHABs), mainly composed of the genus Microcystis, occur frequently throughout the Laurentian Great Lakes. We used artificial neural networks (ANNs) involving 31 hydrological and meteorological predictors to model total phytoplankton (as chlorophyll a) and Microcystis biomass from 2009 to 2011 in western Lake Erie. Continuous ANNs provided modeled-measured correspondences (and modeling efficiencies) ranging from 0.87 to 0.97 (0.75 to 0.94) and 0.71 to 0.90 (0.45 to 0.88) for training–cross-validation and test data subsets of chlorophyll a concentrations and Microcystis biovolumes, respectively. Classification ANNs correctly assigned up to 94% of instances for Microcystis presence–absence. The influences of select predictors on phytoplankton and CyanoHAB niches were visualized using biplots and three-dimensional response surfaces. These then were used to generate mathematical expressions for the relationships between modeled CyanoHAB outcomes and the direct and interactive influences of environmental factors. Based on identified conditions (∼40 to 50 μg total phosphorus (TP)·L−1, 22 to 26 °C, and prolonged wind speeds less than ∼19 km·h−1) underlying the likelihood of occurrence and accumulation of phytoplankton and Microcystis, a “target” concentration of 30 μg TP·L−1 appears appropriate for alleviating blooms. ANNs generated robust ecological niche models for Microcystis, providing a predictive framework for quantitative visualization of nonlinear CyanoHAB–environmental interactions.

Magnetic resonance and ultrasound imaging have shown hamstring strain injuries occur most often in the biceps femoris long head (BFLH), and particularly in the proximal vs. distal region of this muscle. Animal research and musculoskeletal modeling (MSK) have detected heterogeneous fascicle behavior within muscle regions, and within fascicles. Understanding architectural behavior differences during muscle contractions may help to discern possible mechanisms behind proximal BFLH injuries. The purpose of our study was to assess the magnitude of shortening of the proximal and distal fascicles of the BFLH under a range of muscle activation levels under isometric conditions using ultrasound imaging (US). Thirteen healthy adults performed targeted sustained isometric contractions while US were taken of the entire BFLH. Measurements of fascicle lengths in both muscle regions were compared at 20%, 30%, 50%, and 67% MVIC. The results showed that while both regions shortened significantly with activation, the proximal fascicles were significantly longer, regardless of activation level (~38%), and shortened significantly more than the distal fascicles overall (~40%), and cumulatively at higher activation levels (30% and above). No significant strain differences were found between the two regions. These data suggest heterogeneous fascicle behavior exists in an absolute sense; however, differences in behavior are eliminated when normalized (strain). Coupled with MSK literature, the absence of regional fascicle strain differences in this study may indicate strain heterogeneity is not detectable at the whole fascicle level. Further knowledge of this commonly strained muscle's regional behavior during dynamic movements could provide evidence of proximal hamstring strain predisposition.

The ontogeny of antisocial behavior (ASB) is rooted in complex gene-environment (G×E) interactions. The best-characterized of these interplays occurs between: a) low-activity alleles of the gene encoding monoamine oxidase A (MAOA), the main serotonin-degrading enzyme; and b) child maltreatment. The purpose of this study was to develop the first animal model of this G×E interaction, to help understand the neurobiological mechanisms of ASB and identify novel targets for its therapy. Maoa hypomorphic transgenic mice were exposed to an early-life stress regimen consisting of maternal separation and daily intraperitoneal saline injections and were then compared with their wild-type and non-stressed controls for ASB-related neurobehavioral phenotypes. Maoa hypomorphic mice subjected to stress from postnatal day (PND) 1 through 7 – but not during the second postnatal week - developed overt aggression, social deficits and abnormal stress responses from the fourth week onwards. On PND 8, these mice exhibited low resting heart rate - a well-established premorbid sign of ASB – and a significant and selective up-regulation of serotonin 5-HT2A receptors in the prefrontal cortex. Notably, both aggression and neonatal bradycardia were rescued by the 5-HT2 receptor antagonist ketanserin (1–3 mg kg−1, IP), as well as the selective 5-HT2A receptor blocker MDL-100,907 (volinanserin, 0.1–0.3 mg kg−1, IP) throughout the first postnatal week. These findings provide the first evidence of a molecular basis of G×E interactions in ASB and point to early-life 5-HT2A receptor activation as a key mechanism for the ontogeny of this condition. This article is part of the Special Issue entitled ‘The neuropharmacology of social behavior: from bench to bedside’.

Experimental studies evaluating the simultaneous effects of consumers, nutrients, and other biotic/abiotic factors on intact, natural food webs are rare, particularly among ecosystems of varying trophic conditions. We conducted a series of in situ studies that used nutrient-diffusing substrata with nitrogen (N) and phosphorus (P) concentrations in a full factorial design in three temperate, limestone streams in Pennsylvania across a trophic gradient (mesotrophic, eutrophic, and hypereutrophic streams). We assessed differences in algal and macroinvertebrate biomass, taxonomic composition, and functional groups relative to amended nutrients across the trophic gradient; as such, these results facilitated predictions about regulators of food web structure. All factors varied significantly among the streams (e.g., algal biomass P = 0.005, macroinvertebrate biomass P

Microbial biofilm nutrient uptake kinetics can provide insight into assimilative mechanisms that regulate stream primary productivity. While kinetic experiments are often performed, little work has estimated uptake in connection with disturbance (removal) or detailed the effects that common scour events may have on benthic microbes; therefore, the goal of this study was to evaluate physical disturbances on benthic stream biofilms to determine effects on phosphorus (P) uptake rate, physiological capability, and abiotic sorption. Artificial substrata were collected from 2 reaches along a temperate stream; resident biofilms were either removed via abrasion (disturbed) or left intact. A series of short-term radiotracer (H 3 33 PO 4 ) experiments were then conducted to measure P uptake. In vivo autofluorescence was measured as a proxy of algal physiological condition. The experiments showed no difference in P-uptake rates (μgP/μgChl/d) between disturbed (x = 0.77 ± 0.11 [SE] μgP/μgChl/d) and intact (x = 0.91 ± 0.17 μgP/μgChl/d) biofilms (t = 0.69, p = 0.492, df = 33). Further, microbial physiology was not depressed by physical disturbance. While killed samples yielded significantly lower uptake compared to live biota (F = 17.51, p = 0.001), abiotic sorption still accounted for a moderate fraction (range = 0.021–0.038 μgP/μgChl/d) of total uptake and thus warrants estimation in metabolic studies. Overall, these findings lend credence to numerous experiments that investigate benthic microbial physiologic responses post-disturbance and highlight the importance of uptake following common physical disturbances that occur in turbulent environments. In addition, our work measured several kinetic constants across both disturbance and temporal gradients, and we discuss their significance within a physiological framework.

Purpose: Toe-in (TI) and toe-in with wider step width (TIW) gait modifications have successfully reduced the internal peak knee adduction moment (KAM) during level walking and stair ascent tasks, respectively, for healthy and knee osteoarthritis populations. However, the concurrent effects of these modifications have not previously been combined to reduce both the first and the second peak KAM during stair ascent or tested among the different knee alignment groups. Therefore, the purpose of this study was to examine effects of TI and TIW gait modifications on knee biomechanics during stair ascent in individuals with varus, neutral, and valgus knee alignments. Methods: Thirty-eight healthy individuals (age 18–30 yr) with varus, neutral, and valgus knee alignments confirmed using radiographs, performed stair ascent in normal, TI, and TIW gait conditions. A 3 × 3 (group × condition) mixed model repeated-measures ANOVA compared alignment groups across the stair ascent gait conditions (P < 0.05). Results: The TI and the TIW reduced the first peak KAM and KAM impulses compared with normal stair ascent. The TIW also reduced the second peak KAM compared with normal gait and reduced KAM impulses compared with TI. The varus group had increased first peak KAM compared with neutral and valgus groups. The TI and the TIW also reduced peak knee flexion moments compared with normal gait. The TIW also reduced peak external rotation moments compared with normal gait. Conclusions: The TIW gait modification seems to be successful in reducing knee joint loading in all three planes during stair ascent, regardless of knee alignment. The success of TIW in varus knee alignments may have important implications for people with medial knee osteoarthritis, or those susceptible to knee osteoarthritis.

The limnology of offshore Lake Erie during periods of extensive (> 70%) ice cover was examined from ship borne sampling efforts in 2007 to 2010, inclusive. Dense and discrete accumulations of the centric filamentous diatom Aulacoseria islandica (> 10 μg Chl- a /L) were located in the isothermal (

Despite the fact that microbial uptake represents an important transformation of nutrients in aquatic ecosystems, few comprehensive studies have identified key parameters and evaluated their relative importance in explaining variation in uptake rates. Therefore, we per- formed an assessment of peer-reviewed literature that reported aquatic microbial phosphorus (P) uptake rates. The search yielded 36 different papers which presented results of 102 uptake esti- mates. We then constructed a meta-analysis to examine the effects of key parameters on uptake. Microbial group (benthic, planktonic), source (culture, wild), and sample time (long, short) were significant parameters in explaining observed variation in published P uptake rates. Planktonic microbes had higher P uptake rates (65 µg P µg chl a -1 d �1 ), compared with benthic (9 µg P µg chl a -1 d �1 ). Lower affinity for P by benthic microbes could be attributed to adnate growth forms, which can create boundary layers separating cells from ambient P and promoting internal P cycling. Cultured microbes exhibited higher P uptake rates compared with wild samples, although this trend was not significant (F = 2.63, p = 0.108), suggesting that cultured microbes in these studies represented reasonable analogues. Shorter sampling times yielded over 3-fold higher P uptake rates (58 µg P µg chl a -1 d �1 ) and appear to represent more accurate estimates of gross uptake. Microbes subject to longer time regimes may be physiologically altered by experi- mental conditions; estimates might therefore not reflect instantaneous uptake. Our results high- light the influence of ecological variation on P assimilation and provide criteria for developing a general model to predict observed variation in microbial P uptake rates.

Roads impact wildlife in a variety of direct and indirect ways. Roads may act as barriers to dispersal, lead to decreasing population size and genetic diversity, change animal behavior, result in direct mortality, and increase habitat disturbance. Road mortality is especially detrimental to long-lived species, such as freshwater turtles, whose population persistence relies on high adult and subadult survivorship to counter high egg and hatchling mortality. The Spotted Turtle (Clemmys guttata) is a small-bodied, freshwater turtle species that is listed as endangered in Canada and proposed for federal listing in the United States. We used a population viability analysis to attempt to quantify the impact that road mortality has on two distinct populations of Spotted Turtles. The baseline model for the North Wetland Complex (NWC) population predicted a probability of quasi-extinction within 150 yr of 20%. The baseline model for the South Wetland Complex (SWC) predicted a probability of quasi-extinction within 150 yr of 24%. Including an estimate of road mortality (modeled as a reduction in adult survival through annual catastrophic events) into the models, the probability of quasiextinction within 150 yr changed to 93% for the NWC and 94% for the SWC. Our results highlight the critical importance that anthropogenic additive adult mortality has on small populations of turtles and the necessity of detailed demographic studies to detect potential declines in populations of long-lived species.

Rapid sedimentation of phytoplankton cells following seasonal blooms is common in lakes and coastal zones throughout the world, yet the fate of these cells is uncertain. Ascertaining the fate of seasonal blooms may be particularly important in ecosystems that experience hypoxia. Benthic stations were sampled seasonally inside and outside of the hypoxic area in Lake Erie to test for differences in chlorophyll a concentrations, algal physiological condition (cell viability) and diatom rejuvenation rates (from enclosure experiments). Hypoxic areas did sustain higher chlorophyll a concentrations compared with oxic sites; however, diatom growth and physiological capability did not differ significantly. Hypoxic areas exhibited exponential growth rates as high as 0.56 day 21 (compared with the oxic station at 0.53 day 21 , P ¼ 0.000) and chlorophyll rejuvenation rates as high as 0.30 day 21 (compared with the oxic station at 0.36 day 21 , P ¼ 0.964). Therefore, sedimentation of phytoplankton cells may not only contribute to the seasonal hypoxia observed in Lake Erie, but those diatoms able to withstand low oxygen concentrations during the summer, once reintroduced into the water column, may also seed subsequent diatom blooms. Initial estimates indicate that the algal pigment present on the bottom of the central basin, likely sedimented from the overlying water, contributed significantly to hypolimnetic oxygen depletion (11‐33%).

article i nfo Lake Michigan has a long history of non-indigenous introductions that have caused significant ecological change. Here we present a summary of eight papers that document recent changes and the current state of the lower food web of southern Lake Michigan after the establishment of large dreissenid populations. Results are based on long-term data sets collected by federal and academic research and monitoring programs that place recent changes into a historic context. Dramatic and significant changes in the lower food web, such as the loss of the spring diatom bloom, large declines in phytoplankton productivity, and a decline of Mysis populations, were directly or indirectly attributed to the expansion of Dreissena rostriformis bugensis. Total phosphorus concentrations and loadings also have decreased in the last 20 years. Changes in the Lake Michigan ecosystem induced by D. r. bugensis have produced conditions in the offshore pelagic region that are similar to oligotrophic Lake Superior. The future state of the lower food web in southern Lake Michigan is difficult to predict, mainly because population trends of D.r. bugensis in cold, offshore regions are unknown. Hence, monitoring programs designed to collect long-term, consistent data on the lower food web of Lake Michigan are essential. Published by Elsevier B.V.

Benthic algal assemblages were surveyed in five Pennsylvania streams in order to examine trends in biomass and taxonomic groups along an acidification gradient. Acidification severity of each stream was estimated from total dissolved aluminum (AlTD), and discharge regression equations were established for each stream using historic data from the EPA Episodic Response Program. Benthic algae were sampled once after an acidic episode in April and again during August base flows. Chlorophyll decreased with increasing episodic severity in April, thus acid episode severity and associated aluminum toxicity may have influenced algal biomass. Cyanophyta biovolume decreased with increasing severity, while Bacillariophyta, Chlorophyta, and Rhodophyta showed no distinct patterns. A diatom, Eunotia exigua, exhibited a parabolic response in April over the AlTD gradient. Episodic acidification severity may influence algal biomass and composition in streams.

Central glutamatergic synapses and the molecular pathways that control them are emerging as common substrates in the pathogenesis of mental disorders. Genetic variation in the contactin associated protein-like 2 (CNTNAP2) gene, including copy number variations, exon deletions, truncations, single nucleotide variants, and polymorphisms have been associated with intellectual disability, epilepsy, schizophrenia, language disorders, and autism. CNTNAP2, encoded by Cntnap2, is required for dendritic spine development and its absence causes disease-related phenotypes in mice. However, the mechanisms whereby CNTNAP2 regulates glutamatergic synapses are not known, and cellular phenotypes have not been investigated in Cntnap2 knockout neurons. Here we show that CNTNAP2 is present in dendritic spines, as well as axons and soma. Structured illumination superresolution microscopy reveals closer proximity to excitatory, rather than inhibitory synaptic markers. CNTNAP2 does not promote the formation of synapses and cultured neurons from Cntnap2 knockout mice do not show early defects in axon and dendrite outgrowth, suggesting that CNTNAP2 is not required at this stage. However, mature neurons from knockout mice show reduced spine density and levels of GluA1 subunits of AMPA receptors in spines. Unexpectedly, knockout neurons show large cytoplasmic aggregates of GluA1. Here we characterize, for the first time to our knowledge, synaptic phenotypes in Cntnap2 knockout neurons and reveal a novel role for CNTNAP2 in GluA1 trafficking. Taken together, our findings provide insight into the biological roles of CNTNAP2 and into the pathogenesis of CNTNAP2-associated neuropsychiatric disorders.

Phytoplankton abundance, as chl a, in Saginaw Bay, Lake Huron was modeled using artificial neural networks. Suites of abiotic variables served as predictors for the trends/patterns in chl a concentrations. Spatial and temporal gradients of sampling stations throughout the bay were evident, with physical/chemical differences arising from hydrological/meteorological forcing and zebra mussel recruitment. Chlorophyll a concentrations displayed corresponding disparities; concentrations differed between the inner and outer bays and varied intra- and inter-annually. Trained networks reproduced the intrinsic variance and magnitude of chl a dynamics. Modeled-measured concentrations best approximated a 1:1 relationship in a hybrid network incorporating both supervised and unsupervised training whereas concentrations greater than 15 μg/L were underestimated in networks utilizing only supervised training, likely because of inadequate training data. Variables indicative of phytoplankton nutrition, acting as proxy measurements of algal biomass, and/or corresponding to descriptors of hydrological and meteorological forcing had the greatest influence upon modeled concentrations. A conjunctive decision tree and a novel sensitivity analysis provided rule-based information and comprehensible interpretation of relationships among multiple predictor variables. From this, the "knowledge" embedded in trained networks proved extractable and usable for ecological theory generation and/or decision making within water-quality problem solving. Forecasting initiatives within the developing Great Lakes Observing System may be best served by embedding neural networks in mechanistic models to quantitatively initialize variables, qualitatively delineate conditions for projecting ecological structure, and/or estimate deviations from predictability within mechanistic simulations.

To evaluate levels of primary production and community metabolism in Lake Erie, we conducted incubations with 18 O-labelled water and determined the ratio of respiration to primary production (R:P) during the summer and early fall of 2002. The epilimnion of Lake Erie was characterized by δ 18 O values less than 0.7‰ at all times that reflects a strong contribution of O 2 from primary production. High δ 18 O values (maximum of 6.6‰) were common in the O 2 depleted waters of the hypolimnion as a consequence of isotope fractionation during respiration. Hypoxic conditions were evident in the central basin in August when the fractional abundance of O 2 reached a minimum value of 0.04. Rates of primary production varied from 0.23 to 1.76 mmol-O 2 .m –3 .h –1 , decreased from west to east in August, and were at a minimum in the central basin in September. Ratios of respiration to photosynthesis (R:P) (determined from the abundance and isotopic composition of dissolved O 2 ) in the epilimnion as low as 0.45 in July were strong evidence of net autotrophy and preceded the development of hypoxia in August. Net heterotrophy prevailed in August and September. The absolute values of R:P ratios were not indicative of trophic state, however, the wide range of R:P ratios (0.45 to 20.40), fraction of O 2 saturation (0.04 to 1.36), and δ 18 O-O 2 (−6.0 to 7.5‰) values were all indicative of a eutrophic system. An average isotope fractionation factor for respiration of 7.9‰ was determined from samples in the hypolimnion in July and August. Based on unique fractionation factors for respiration in the water column (23.5‰) and in sediments (3‰) we calculate that 61% of hypolimnion O 2 respiration occurs within sediments and 39% occurs within the water column.

Depleted oxygen levels in Lake Erie once resulted in massive fish die-offs and changes in the lake's gross chemistry and biology. Given the reductions in phosphorus loads to the lake and recent invasion by Dreissenid mussels, it is likely that the sources of primary production within the lake will shift (surface, subsurface, or benthic), and that these changes may influence the lake's oxygen balance. From 1997–98, the biomass and taxonomic composition of major algal assemblages was measured (surface, subsurface, and benthic) at 16 sites throughout the entire lake (n = 100). Following thermal stratification, a subsurface phytoplankton assemblage developed in the deep waters (15–40 m depth) of all three basins in Lake Erie, and its biomass was significantly greater than surface phytoplankton (2.70 versus 1.91 mg chl/m 3 ). In the eastern basin, all samples collected from lake sediments contained considerable concentrations of phaeopigments, while only 32% of the samples contained chlorophyll (8 of 25 samples). Microscopic analysis confirmed that viable benthic algae were present in all samples analyzed (range from 6.8 to 35.2 mg C/m 2 ); however because most were pelagic diatom species, it is likely they settled out the water column. Dissolved oxygen concentrations varied 10-fold among the 57 samples taken in Lake Erie from July-October (range 1.35 to 13.26 mg/L). Most of this variation was related to changes in concentration with water column depth, with the lower values being measured in bottom waters. In the eastern basin, hypolimnetic depletion rates were similar to those measured during the 1970–80s (1.6 to 2.2 mg O 2 /L/month). Therefore, despite the occurrence of both subsurface phytoplankton and benthic algal assemblages, the rate of hypolimnetic oxygen depletion in the eastern basin of Lake Erie has not changed, suggesting that physical factors play a major role in mediating this process.

The influence of episodic, sediment resuspension on phytoplankton abundance/volume and composition, the photosynthetic maximum rate P B and efficiency B , and chlorophyll-specific growth Chl was evaluated during the spring isothermal period in southern Lake Michigan Laurentian Great Lakes, USA. Resuspension altered the nutrient and light climate of nearshore waters; light attenuation Kd and phosphorus concentrations corresponded p 0.0001 and p 0.001, respectively with concentrations of suspended particulate matter SPM. Phytoplankton cell volume and diatom cell abundance and volume were not associated with SPM concentrations p 0.05. Diatom composition displayed spatial dissimilarities corresponding with resuspension p 0.001; small centric diatoms exhibiting meroplanktonic life histories and pennate diatoms considered benthic in origin were most abundant within SPM-impacted, nearshore waters whereas taxa typically comprising assemblages in optically-clear, offshore waters and the basin-wide, spring bloom were not. Values of P B and B corresponded p 0.0001 with both Kd coefficients and SPM concentrations, potentially reflecting increased light harvesting/utilization within impacted assemblages. However, integral production was inversely associated with Kd coefficients and SPM concentrations p 0.0001 and photosynthesis was light-limited or nearly so for most assemblages. Although Chl values corresponded with Kd coefficients p 0.05, values were quite low x S.E., 0.10 0.004 d ‐1 throughout the study. Most likely, distinct rate processes between SPM- and nonimpacted assemblages reflected short-term compositional and corresponding physiological variations due to infusion of meroplankton and/or tributary-derived phytoplankton. Overall, resuspension appears to have little, if any, long-term impact upon the structure and function of the lake’s phytoplankton.