Diet Overlap and Food Habitats of Slimy Sculpin, Deepwater Sculpin, and Round Goby During Winter and Spring in Offshore Lake Michigan

Ecological stability in offshore benthic food webs of the Laurentian Great Lakes has been recently altered by non-native species such as round goby Neogobius melanostomus and quagga mussels Dreissena bugensis, as well as steep declines in biomass of Diporeia, a native amphipod. Correspondingly, population dynamics, life histories and the diet composition of native sculpins may be affected. I examined food habits of slimy sculpin Cottus cognatus, deepwater sculpin Myoxocephalus thompsonii, and round goby collected from January to May in 2009 and 2010 in Lake Michigan offshore of Frankfort (FF), MI; Muskegon (MSK), MI; Two Rivers (TR), WI; and Sturgeon Bay (STB), WI in depths of 69-128m. Important prey (by dry weight proportion and % occurrence) for slimy sculpin were Mysis (0.34, 45%), Diporeia (0.16, 34%), and Limnocalanus macrurus (0.22, 68%). Prey important to deepwater sculpin were Mysis (0.74, 92%) and Diporeia (0.16, 54%). Round goby consumed mainly bivalves (0.68, 95%) and Mysis (0.15, 37%). Diet composition for all three species did not vary across days sampled in January through April, and little variance was explained by year or depth sampled. Variance in diet composition for each benthivore species was best explained by the site from which fishes were sampled. For example, Diporeia constituted high diet proportions in sculpins offshore of TR and STB, but was absent in sculpins offshore of FF and MSK. Significant diet overlap (Schoener’s index ≥ 0.60) was identified between slimy and deepwater sculpin offshore of FF and STB but not offshore of TR. Significant diet overlap was not found between round goby and either sculpin species. Non-metric multi-dimensional scaling and cluster analyses revealed groups of fishes at each site with similar diets: 1) slimy sculpin only; 2) round goby only, and; 3) all deepwater sculpin, some slimy sculpin individuals, and very few round goby. Cluster analysis also distinguished groups for both sculpin species that reinforced the diet overlap results. Using genetic analyses on fish eggs taken from diet samples, bloater Coregonus hoyi and deepwater sculpin eggs were confirmed prey for slimy and deepwater sculpin in each month from February through May at all four sites sampled. Round goby consumed few deepwater sculpin eggs and no bloater eggs.Master of ScienceNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/88164/1/londer absolute final.pd

Trophic relationships, distribution and interactions among invasive and native Laurentian Great Lakes biota assessed using metabarcoding of stomach content DNA (scDNA) and environmental DNA (eDNA)

As aquatic invasive species (AIS) proliferate, they pose serious threats to native taxa, foodwebs and ecosystems. Massively-parallel, high-throughput, next-generation sequencing (NGS) and metabarcoding of environmental DNA (eDNA) and predator stomach content DNA (scDNA) are new approaches to detect AIS and can facilitate detailed analyses of AIS impacts. Using such technology, degraded and digested samples, and cryptic taxa can be identified with high sensitivity. The Laurentian Great Lakes (Great Lakes) are highly invaded and to determine occurrence patterns of AIS and native species inhabiting them I used a shortened portion of Cytochrome Oxidase One (CO1) and NGS metabarcoding. I developed, optimized and validated novel target-species CO1 PCR primer sets for AIS invertebrates: Bythotrephes longimanus, Cercopagis pengoi, Dreissena rostriformis bugensis, Dreissena polymorpha, and Hemimysis anomala. I tested primer set sensitivities, specificities, and multiplexing and used these with universal primer sets to analyze field-sampled scDNA and eDNA. I analyzed influences of abiotic (spatiotemporal) and biotic (predator species and size) variables in relation to prey occurrences in scDNA. The lowest AIS DNA in detected with novel primer sets in PCRs was: B. longimanus = 2.07; C. pengoi = 0.0002; D. r. bugensis = 0.0009; D. polymorpha = 0.103; and H. anomala = 0.127 (Chapter 2). Detection limits within mixes of interfering DNA (as percentage of total DNA) were: B. longimanus = 3.90 %, C. pengoi = 0.003 %, D. r. bugensis = 0.020 %, D. polymorpha = 0.170 % and H. anomala = 0.019 %. To determine invertebrate AIS roles in Lake Michigan, I metabarcoded scDNA from alewife (Alosa pseudoharengus), bloater (Coregonus hoyi), ninespine stickleback (Pungitius pungitius), rainbow smelt (Osmerus mordax) and slimy sculpin (Cottus cognatus) sampled Spring 2009 and 2010 at 73-128 m depths from three offshore sites. I detected multiple occurrences of target AIS and three native prey (Leptodiaptomus sicilis, Limnocalanus macrurus, and Mysis diluviana; Chapter 3). Driving variation in occurrences of the AIS and native taxa in scDNA was sample site, highlighting localized ecological and foodweb differences in ongoing AIS roles and impacts. Predator species effects likely reflected realized ecological feeding niches. To metabarcode scDNA from Lake Erie commercially fished predator species walleye (Sander vitreus), white bass (Morone chrysops), white perch (Morone americana) and yellow perch (Perca flavescens), I used novel AIS primer sets (Chapter Two) and a universal primer set to target fishes. Three invertebrate AIS including C. pengoi, B. longimanus, and D. r. bugensis, and AIS prey fishes gizzard shad (Dorosoma cepedianum), rainbow smelt and round goby (Neogobius melanostomus), and native prey fishes channel catfish (Ictalurus punctatus) and emerald shiner (Notropis athernoides) were detected, and all were relatively common components of scDNA. Occurrence patterns varied significantly with season, predator species, year, and predator size; however, the significances of factors also varied with prey species. Prey occurrences revealed dynamics among native and AIS prey and predators, potential competition, or prey selectivity which varied by way of these factors (Chapter 4). In 2013, 43 sites each in the Sydenham and Grand Rivers were sampled and metabarcoded for invertebrate eDNA using a universal primer set. Data revealed spatial patterns of AIS at sites within and among each river. Key AIS identified were: D. r. bugensis, Branchiura sowerbyi, Potamothrix moldaviensis, Craspedacusta sowerbyi and Skistodiaptomus pallidus. Further, I identified rare native mollusks including Quadrula quadrula and Villosa fabalis - threatened and endangered species in lower and middle reaches of the Sydenham. Novel results and information will provide important guidance to those tasked with ongoing challenges of managing, slowing spread of and eradicating AIS, and conserving native species

Evaluating the Efficacy of Video Self-Modeling Social Skills in Children With Autism Spectrum Disorder

The inability to display social reciprocity is a hallmark criterion of autism spectrum disorder (ASD). This lack of proper social skills (i.e., eye contact, cooperative play, and reciprocal interaction) indicates the importance of purposeful interaction, about which a research gap exists. The theoretical framework for this study was social learning theory, by which Bandura (1977) posited that learning occurs by observing the behavior of others. The current study involved examining the effectiveness of an intervention conducted with children who have ASD. The purpose of the intervention was to increase children’s playground social skills by having them watch themselves at play via video (i.e., video self-modeling [VSM]). Videos of three boys ages 5 to 10 years, who were nonverbal, diagnosed with ASD, and lacked social skills were observed. The number of times playground social skills (i.e., eye contact, cooperative play, and reciprocal action) were witnessed were recorded before and after the VSM intervention. Four research questions were examined to determine whether children with ASD exhibited a marked increase in playground social skills (i.e., eye contact, cooperative play, and reciprocal action) following VSM treatment. Specifically, the number of times the child interacted with another was tallied. Results revealed substantial improvement in the social skills of the children with ASD. The use of VSM in this population has implications for positive social change, as children with ASD could be better able to gain the social skills and tools necessary to interact with others. The results of this study could be used to support interventions for providers, further enhance the social skills of children with autism, and provide information to caregivers on how to best support their children and techniques they can use

Evaluating the Efficacy of Video Self-Modeling Social Skills in Children With Autism Spectrum Disorder

The inability to display social reciprocity is a hallmark criterion of autism spectrum disorder (ASD). This lack of proper social skills (i.e., eye contact, cooperative play, and reciprocal interaction) indicates the importance of purposeful interaction, about which a research gap exists. The theoretical framework for this study was social learning theory, by which Bandura (1977) posited that learning occurs by observing the behavior of others. The current study involved examining the effectiveness of an intervention conducted with children who have ASD. The purpose of the intervention was to increase children’s playground social skills by having them watch themselves at play via video (i.e., video self-modeling [VSM]). Videos of three boys ages 5 to 10 years, who were nonverbal, diagnosed with ASD, and lacked social skills were observed. The number of times playground social skills (i.e., eye contact, cooperative play, and reciprocal action) were witnessed were recorded before and after the VSM intervention. Four research questions were examined to determine whether children with ASD exhibited a marked increase in playground social skills (i.e., eye contact, cooperative play, and reciprocal action) following VSM treatment. Specifically, the number of times the child interacted with another was tallied. Results revealed substantial improvement in the social skills of the children with ASD. The use of VSM in this population has implications for positive social change, as children with ASD could be better able to gain the social skills and tools necessary to interact with others. The results of this study could be used to support interventions for providers, further enhance the social skills of children with autism, and provide information to caregivers on how to best support their children and techniques they can use

Breast cancer spatial heterogeneity in near-infrared spectra and the prediction of neoadjuvant chemotherapy response

We describe an algorithm to calculate an index that characterizes spatial differences in broadband near-infrared [(NIR), 650–1000 nm] absorption spectra of tumor-containing breast tissue. Patient-specific tumor spatial heterogeneities are visualized through a heterogeneity spectrum function (HS). HS is a biomarker that can be attributed to different molecular distributions within the tumor. To classify lesion heterogeneities, we built a heterogeneity index (HI) derived from the HS by weighing the HS in specific NIR absorption bands. It is shown that neoadjuvant chemotherapy (NAC) response is potentially related to the tumor heterogeneity. Therefore, we correlate the heterogeneity index obtained prior to treatment with the final response to NAC. From a pilot study of 15 cancer patients treated with NAC, pathological complete responders (pCR) were separated from non-pCR according to their HI (–44 ± 12 and 43 ± 17, p = 3 × 10(−8), respectively). We conclude that the HS function is a biomarker that can be used to visualize spatial heterogeneities in lesions, and the baseline HI prior to therapy correlates with chemotherapy pathological response

Using Diets to Reveal Overlap and Egg Predation among Benthivorous Fishes in Lake Michigan

Ecological stability in the Laurentian Great Lakes has been altered by nonindigenous species, such as the Round Goby Neogobius melanostomus and dreissenid mussels, and by declines in native amphipods Diporeia spp. We evaluated whether these changes could influence diet overlap between three benthivorous fishes (Slimy Sculpin Cottus cognatus, Deepwater Sculpin Myoxocephalus thompsonii, and Round Goby) and whether predation on eggs of native species was occurring. We examined diets of fish collected at depths of 69â 128 m in Lake Michigan offshore of Frankfort and Muskegon, Michigan, and Two Rivers and Sturgeon Bay, Wisconsin, during Januaryâ May 2009 and 2010. Important prey (by dry weight proportion and by percent frequency of occurrence) for Slimy Sculpin were Mysis (0.34; 45%), Diporeia (0.16; 34%), and Limnocalanus macrurus (0.22; 68%); important prey for Deepwater Sculpin were Mysis (0.74; 92%) and Diporeia (0.16; 54%). Round Goby consumed mainly bivalves (i.e., dreissenids: 0.68; 95%) and Mysis (0.15; 37%). The two sculpin species consumed the eggs of Bloaters Coregonus hoyi (Slimy Sculpin: 0.04, 11%; Deepwater Sculpin: 0.02, 7%) and the eggs of Deepwater Sculpin (Slimy Sculpin: 0.03, 13%; Deepwater Sculpin: 0.05, 16%) during Februaryâ May at all sites. Round Goby also consumed eggs of these species but at lower levels (â ¤0.01; <1%). Diet overlap was identified between sculpin species at Frankfort and Sturgeon Bay, suggesting possible interspecific competition, but their diets did not overlap at Two Rivers; diet overlap was never observed between Round Goby and either sculpin species. Given that (1) diet overlap varied by site and (2) diet proportions varied spatially more than temporally, benthivores appear to be exhibiting localized responses to recent ecological changes. Overall, these results reveal that egg predation and interspecific competition could be important interactions to consider in future examinations of the population dynamics of these species or in ecosystem models that forecast how fisheries will respond to possible perturbations or management scenarios.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141248/1/tafs0492.pd

Physiological function and catalytic versatility of bacterial multihaem cytochromescinvolved in nitrogen and sulfur cycling

Bacterial MCCs (multihaem cytochromes c) represent widespread respiratory electron-transfer proteins. In addition, some of them convert substrates such as nitrite, hydroxylamine, nitric oxide, hydrazine, sulfite, thiosulfate or hydrogen peroxide. In many cases, only a single function is assigned to a specific MCC in database entries despite the fact that an MCC may accept various substrates, thus making it a multifunctional catalyst that can play diverse physiological roles in bacterial respiration, detoxification and stress defence mechanisms. The present article briefly reviews the structure, function and biogenesis of selected MCCs that catalyse key reactions in the biogeochemical nitrogen and sulfur cycles

Population‐level effects of egg predation on a native planktivore in a large freshwater lake

Using a 37‐year recruitment time series, we uncovered a field pattern revealing a strong, inverse relationship between bloater Coregonus hoyi recruitment success and slimy sculpin Cottus cognatus biomass in Lake Michigan (United States), one of the largest freshwater lakes of the world. Given that slimy sculpins (and deepwater sculpin Myoxocephalus thompsonii ) are known egg predators that spatiotemporally overlap with incubating bloater eggs, we used recently published data on sculpin diets and daily ration to model annual bloater egg consumption by sculpins for the 1973–2010 year‐classes. Although several strong year‐classes were produced in the late 1980s when the proportion of eggs consumed by slimy sculpins was extremely low (i.e., 0.10–1.0), egg predation failed to explain why recruitment was weak for the 1995–2005 year‐classes when the proportion consumed was also low (i.e., <0.02). We concluded that egg predation by slimy and deepwater sculpins could have limited bloater recruitment in some years, but that some undetermined factor was more important in many other years. Given that slimy sculpin densities are influenced by piscivorous lake trout Salvelinus namaycush , the restoration of which in Lake Michigan has lagged behind those in lakes Superior and Huron, our study highlights the importance of an ecosystem perspective when considering population dynamics of fishes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108675/1/eff12112.pd

Cytochrome c4 is required for siderophore expression by Legionella pneumophila, whereas cytochromes c1 and c5 promote intracellular infection

A panel of cytochrome c maturation (ccm) mutants of Legionella pneumophila displayed a loss of siderophore (legiobactin) expression, as measured by both the chrome azurol S assay and a Legionella-specific bioassay. These data, coupled with the finding that ccm transcripts are expressed by wild-type bacteria grown in deferrated medium, indicate that the Ccm system promotes siderophore expression by L. pneumophila. To determine the basis of this newfound role for Ccm, we constructed and tested a set of mutants specifically lacking individual c-type cytochromes. Whereas ubiquinol-cytochrome c reductase (petC) mutants specifically lacking cytochrome c1 and cycB mutants lacking cytochrome c5 had normal siderophore expression, cyc4 mutants defective for cytochrome c4 completely lacked legiobactin. These data, along with the expression pattern of cyc4 mRNA, indicate that cytochrome c4 in particular promotes siderophore expression. In intracellular infection assays, petC mutants and cycB mutants, but not cyc4 mutants, had a reduced ability to infect both amoebae and macrophage hosts. Like ccm mutants, the cycB mutants were completely unable to grow in amoebae, highlighting a major role for cytochrome c5 in intracellular infection. To our knowledge, these data represent both the first direct documentation of the importance of a c-type cytochrome in expression of a biologically active siderophore and the first insight into the relative importance of c-type cytochromes in intracellular infection events