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1.
Ecol Evol ; 14(4): e11266, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38633525

ABSTRACT

Wolves are assumed to be ungulate obligates, however, a recently described pack on Pleasant Island, Alaska USA, is persisting on sea otters and other marine resources without ungulate prey, violating this long-held assumption. We address questions about these wolves regarding their origin and fate, degree of isolation, risk of inbreeding depression, and diet specialization by individual and sex. We applied DNA metabarcoding and genotyping by amplicon sequencing using 957 scats collected from 2016 to 2022, and reduced representation sequencing of tissue samples to establish a detailed understanding of Pleasant Island wolf ecology and compare them with adjacent mainland wolves. Dietary overlap was higher among individual wolves on Pleasant Island (Pianka's index mean 0.95 ± 0.03) compared to mainland wolves (0.70 ± 0.21). The individual diets of island wolves were dominated by sea otter, ranging from 40.6% to 63.2% weighted percent of occurrence (wPOO) (mean 55.5 ± 8.7). In contrast, individual mainland wolves primarily fed on ungulates (42.2 ± 21.3) or voles during a population outbreak (31.2 ± 23.2). We traced the origin of the Pleasant Island pack to a mainland pair that colonized around 2013 and produced several litters. After this breeding pair was killed, their female offspring and an immigrant male became the new breeders in 2019. We detected 20 individuals of which 8 (40%) were trapped and killed while two died of natural causes during the 6-year study. Except for the new breeding male, the pedigree analysis and genotype results showed no additional movement to or from the island, indicating limited dispersal but no evidence of inbreeding. Our findings suggest wolves exhibit more flexible foraging behavior than previously believed, and hunting strategies can substantially differ between individuals within or between packs. Nevertheless, anthropogenic and natural mortality combined with limited connectivity to the mainland may inhibit the continued persistence of Pleasant Island wolves.

2.
Eur J Oncol Nurs ; 70: 102588, 2024 Apr 10.
Article in English | MEDLINE | ID: mdl-38669955

ABSTRACT

PURPOSE: Complementary and integrative medicine (CIM) therapies (i.e., non-conventional Western medicine interventions) may reduce side-effects associated with pediatric oncology treatment. CIM therapies may also improve caregiver psychological and physical health that is exacerbated during pediatric cancer treatment. Despite known benefits, these therapies are not widely used within pediatric oncology populations in the United States. To guide and promote CIM use among this population, the aim of this project was to qualitatively explore factors that contribute to caregivers' decision to include CIM use in their own and child's care. METHODS: Twenty caregivers of children (ages 0.5-14 years) being treated for cancer participated in this study. Each completed a demographic form and the CIM use questionnaire. Qualitative interviews followed by a card sort task were used to assess barriers and facilitators of uptake for caregivers and their child with cancer. RESULTS: A number of predisposing (e.g., child age, beliefs) and needs factors (e.g., potential to treatment-related side-effects) provide insight into caregivers' decisions to use CIM for their child. Analyses also revealed the importance of enabling factors (e.g., resources) for caregiver use. Caregivers also reported benefiting from additional information about risk/benefit analysis of these therapies, and current research for CIM use in caregivers and children being treated for cancer. CONCLUSION: Children may benefit from individually tailored complementary and integrative medicine consultations that explore patient history and specific needs factors to improve preference concordant care and uptake. Caregivers may benefit from support that improves enabling factors associated with care (e.g., improved accessibility).

3.
EJHaem ; 5(1): 11-20, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38406507

ABSTRACT

Pain is the hallmark symptom causing morbidity for people with sickle cell disease (SCD) and may present as nociceptive, neuropathic, or mixed type pain. Neuropathic pain (NP) is underrecognized and undertreated in patients with SCD and is associated with decreased patient-reported quality of life. Surveys were completed by clinicians caring for adolescents with SCD in the outpatient setting. SCD patients ages 1418 at increased risk of NP completed a patient-facing survey at a scheduled clinic visit. Ninety-four percent of responding clinicians agreed that NP significantly contributes to reported pain in SCD. Clinicians believed that NP medications are effective for reducing chronic pain (62%) and decreasing opioid utilization (44%). Clinician-identified barriers to prescribing NP medications included concerns about medication adherence (82%), lack of pediatric guidelines for NP medications (70%), and perceived patient concern about side effects (65%). More than 1/3 (35%) of clinicians reported that they were not comfortable managing NP medications. Clinician-identified barriers to referral to a pain management specialist included scheduling concerns (88%) and perceived patient/family lack of interest (77%). Most patients expressed willingness to take a medication for NP (78%), see a pain management specialist (84%), or learn more about nonpharmacologic interventions (72%), although most (51%) also reported some concerns about taking a medication for NP, citing insufficient knowledge (34%), and potential for side effects (32%). A minority of respondents (15%) worried about referral to a pain management specialist. Clinician and patient perspectives provide insights that may guide education efforts or other interventions to improve treatment of SCD-related NP.

4.
Cancer ; 129(13): 2075-2083, 2023 07 01.
Article in English | MEDLINE | ID: mdl-36943740

ABSTRACT

BACKGROUND: There is limited understanding of associations between a combination of health behaviors (physical activity, sedentary/screen-time, diet) and cardiometabolic health risk factors, physical performance, and emotional health among young (<18) childhood cancer survivors (CCS). The aims of this research were to address this gap by 1) deriving health behavior adherence profiles among CCS, and 2) examining associations among demographic, diagnosis and/or treatment exposures, cardiometabolic, physical performance, and emotional functioning with health behavior profile membership. METHODS: Participants included 397 CCS (≥5 years post-diagnosis; 10-17 years old) enrolled in the St. Jude Lifetime Cohort Study who completed physical health evaluations and questionnaires assessing health behaviors and psychological functioning. Latent profile analysis was used to derive profiles of health behavior adherence. Logistic regression and t-tests were used to examine mean-level differences and associations between profile membership with demographic, diagnosis, treatment exposures, cardiometabolic health, psychological functioning, and physical performance. RESULTS: Two profiles emerged: inactive-unhealthy-diet ("IU") and active-sedentary-unhealthy-diet ("ASU") to guidelines. More participants in IU demonstrated higher resting heart rate (mean [M], 76.54; SD = 12.00) and lower motor proficiency scores (M = 34.73; SD = 29.15) compared to ASU (resting heart rate, M = 71.95, SD = 10.74; motor proficiency, M = 50.40, SD = 31.02). CONCLUSIONS: CCS exhibited low adherence to multiple health behavior guidelines, with adherence patterns differentially associated with cardiometabolic health (i.e., resting heart rate) and physical performance. However, robust protection against all health variables was not observed. Findings suggest interventions designed to improve health outcomes should target multiple health behaviors simultaneously. PLAIN LANGUAGE SUMMARY: Pediatric cancer survivors are at-risk for detrimental health outcomes associated with cancer and treatment. Engagement in healthy lifestyle behaviors serves to reduce health vulnerabilities among adult survivors but less is known about associations with lifestyle behaviors on young survivors. This study documents patterns of lifestyle behaviors among survivors of pediatric cancer, factors that increase susceptibility to nonadherence, and associations among lifestyle behaviors and health indicators.


Subject(s)
Cancer Survivors , Cardiovascular Diseases , Neoplasms , Humans , Child , Adolescent , Cohort Studies , Neoplasms/epidemiology , Neoplasms/therapy , Neoplasms/psychology , Survivors , Health Behavior
5.
Proc Natl Acad Sci U S A ; 120(5): e2209037120, 2023 Jan 31.
Article in English | MEDLINE | ID: mdl-36689656

ABSTRACT

Sea otters (Enhydra lutris) and wolves (Canis lupus) are two apex predators with strong and cascading effects on ecosystem structure and function. After decades of recovery from near extirpation, their ranges now overlap, allowing sea otters and wolves to interact for the first time in the scientific record. We intensively studied wolves during 2015 to 2021 in an island system colonized by sea otters in the 2000s and by wolves in 2013. After wolf colonization, we quantified shifts in foraging behavior with DNA metabarcoding of 689 wolf scats and stable isotope analyses, both revealing a dietary switch from Sitka black-tailed deer (Odocoileus hemionus), the terrestrial in situ primary prey, to sea otters. Here we show an unexpected result of the reintroduction and restoration of sea otters, which became an abundant marine subsidy for wolves following population recovery. The availability of sea otters allowed wolves to persist and continue to reproduce, subsequently nearly eliminating deer. Genotypes from 390 wolf scats and telemetry data from 13 wolves confirmed island fidelity constituting one of the highest known wolf population densities and upending standardly accepted wolf density predictions based on ungulate abundance. Whereas marine subsidies in other systems are generally derived from lower trophic levels, here an apex nearshore predator became a key prey species and linked nearshore and terrestrial food webs in a recently deglaciated and rapidly changing ecosystem. These results underscore that species restoration may serve as an unanticipated nutrient pathway for recipient ecosystems even resulting in cross-boundary subsidy cascades.


Subject(s)
Deer , Otters , Wolves , Animals , Ecosystem , Predatory Behavior , Food Chain , Population Dynamics
6.
Mol Ecol Resour ; 22(3): 962-977, 2022 Apr.
Article in English | MEDLINE | ID: mdl-34601818

ABSTRACT

Metabarcoding of environmental DNA (eDNA) is now widely used to build diversity profiles from DNA that has been shed by species into the environment. There is substantial interest in the expansion of eDNA approaches for improved detection of terrestrial vertebrates using invertebrate-derived DNA (iDNA) in which hematophagous, sarcophagous, and coprophagous invertebrates sample vertebrate blood, carrion, or faeces. Here, we used metabarcoding and multiple iDNA samplers (carrion flies, sandflies, and mosquitos) collected from 39 forested sites in the southern Amazon to profile gamma and alpha diversity. Our main objectives were to (1) compare diversity found with iDNA to camera trapping, which is the conventional method of vertebrate diversity surveillance; and (2) compare each of the iDNA samplers to assess the effectiveness, efficiency, and potential biases associated with each sampler. In total, we collected and analysed 1759 carrion flies, 48,686 sandflies, and 4776 mosquitos. Carrion flies revealed the greatest total vertebrate species richness at the landscape level, despite the least amount of sampling effort and the fewest number of individuals captured for metabarcoding, followed by sandflies. Camera traps had the highest median species richness at the site-level but showed strong bias towards carnivore and ungulate species and missed much of the diversity described by iDNA methods. Mosquitos showed a strong feeding preference for humans as did sandflies for armadillos, thus presenting potential utility to further study related to host-vector interactions.


Subject(s)
DNA Barcoding, Taxonomic , Diptera , Environmental Monitoring , Vertebrates , Animals , Biodiversity , Culicidae , DNA Barcoding, Taxonomic/methods , Humans , Psychodidae/genetics , Vertebrates/genetics
7.
J Adolesc Young Adult Oncol ; 11(6): 611-616, 2022 12.
Article in English | MEDLINE | ID: mdl-34936831

ABSTRACT

Complex regional pain syndrome (CRPS) is a debilitating disorder that causes significant pain and can decrease the quality of life of affected individuals. This is the first report of CRPS in an adolescent oncology patient, whose symptoms successfully resolved with 3 weeks of intensive, multimodal, and multidisciplinary therapies. She experienced a complete return to pre-CRPS functional status within 10 weeks. The successful outcome of this case highlights the importance of early recognition of CRPS in the adolescent population and the need for a multimodal intensive treatment regimen to prevent the development of chronic pain and loss of limb function.


Subject(s)
Complex Regional Pain Syndromes , Precursor Cell Lymphoblastic Leukemia-Lymphoma , Adolescent , Humans , Quality of Life , Combined Modality Therapy , Complex Regional Pain Syndromes/therapy , Precursor Cell Lymphoblastic Leukemia-Lymphoma/complications , Precursor Cell Lymphoblastic Leukemia-Lymphoma/therapy
9.
Sci Rep ; 11(1): 763, 2021 01 12.
Article in English | MEDLINE | ID: mdl-33436940

ABSTRACT

Understanding how a pathogen can grow on different substrates and how this growth impacts its dispersal are critical to understanding the risks and control of emerging infectious diseases. Pseudogymnoascus destructans (Pd) causes white-nose syndrome (WNS) in many bat species and can persist in, and transmit from, the environment. We experimentally evaluated Pd growth on common substrates to better understand mechanisms of pathogen persistence, transmission and viability. We inoculated autoclaved guano, fresh guano, soil, and wood with live Pd fungus and evaluated (1) whether Pd grows or persists on each (2) if spores of the fungus remain viable 4 months after inoculation on each substrate, and (3) whether detection and quantitation of Pd on swabs is sensitive to the choice to two commonly used DNA extraction kits. After inoculating each substrate with 460,000 Pd spores, we collected ~ 0.20 g of guano and soil, and swabs from wood every 16 days for 64 days to quantify pathogen load through time using real-time qPCR. We detected Pd on all substrates over the course of the experiment. We observed a tenfold increase in pathogen loads on autoclaved guano and persistence but not growth in fresh guano. Pathogen loads increased marginally on wood but declined ~ 60-fold in soil. After four months, apparently viable spores were harvested from all substrates but germination did not occur from fresh guano. We additionally found that detection and quantitation of Pd from swabs of wood surfaces is sensitive to the DNA extraction method. The commonly used PrepMan Ultra Reagent protocol yielded substantially less DNA than did the QIAGEN DNeasy Blood and Tissue Kit. Notably the PrepMan Ultra Reagent failed to detect Pd in many wood swabs that were detected by QIAGEN and were subsequently found to contain substantial live conidia. Our results indicate that Pd can persist or even grow on common environmental substrates with results dependent on whether microbial competitors have been eliminated. Although we observed clear rapid declines in Pd on soil, viable spores were harvested four months after inoculation. These results suggest that environmental substrates and guano can in general serve as infectious environmental reservoirs due to long-term persistence, and even growth, of live Pd. This should inform management interventions to sanitize or modify structures to reduce transmission risk as well early detection rapid response (EDRR) planning.


Subject(s)
Ascomycota/growth & development , Chiroptera/microbiology , Wood/microbiology , Animals , Ascomycota/genetics , Hibernation , Sequence Analysis, DNA/methods , Soil Microbiology
10.
J Clin Psychol Med Settings ; 28(3): 468-476, 2021 09.
Article in English | MEDLINE | ID: mdl-33170412

ABSTRACT

This study retrospectively investigated psychological factors contributing to chronic post-surgical pain (CPSP) in pediatric patients after limb-sparing or amputation surgery for extremity osteosarcoma. Psychological factors were identified and analyzed by the Wilcoxon rank-sum and median two-sample tests. Univariate and multivariate Cox regressions were performed using gender, age, psychological factors, and psychological interventions related to CPSP duration as covariates. Duration of pain treatment was significantly longer in patients resistant to psychological interventions (p = 0.01) than those receptive to interventions. Shorter duration of pain treatment was associated with older age (p = 0.03) and receptiveness to psychological interventions (HR = 4.19, 95% CI [1.22, 14.35]). Older age and receptiveness to psychological interventions as part of pain management care are associated with needing a shorter duration of pain treatment. Our results highlight the importance of prospective investigations evaluating motivation to engage in psychotherapy and psychological interventions and identify risk factors for CPSP in pediatric oncology.


Subject(s)
Bone Neoplasms , Chronic Pain , Osteosarcoma , Aged , Bone Neoplasms/complications , Child , Chronic Pain/therapy , Humans , Osteosarcoma/complications , Osteosarcoma/surgery , Pain, Postoperative/therapy , Prospective Studies , Retrospective Studies , Risk Factors
11.
Psychol Serv ; 17(S1): 98-109, 2020.
Article in English | MEDLINE | ID: mdl-31380678

ABSTRACT

Consistent with the core underpinnings of advocacy within the field of pediatrics, the discipline of pediatric psychology places an emphasis on advocating for children through clinical and research efforts as well as through a systems approach of interdisciplinary collaboration and partnering with others. In the current article, the role of advocacy efforts for pediatric psychologists within children's hospitals are highlighted. Various forms and models of advocacy are discussed, particularly as they relate to individual and organizational advocacy within children's hospitals, as well as interdisciplinary collaboration and shared advocacy with other health care providers and leadership. Training of pediatric psychologists in advocacy is also addressed, including limitations in development and application of advocacy skills for pediatric psychologists. Examples of policy change at the hospital/institutional, state, and national levels are also provided. While pediatric psychologists are in unique positions to advocate for their patients within interdisciplinary health care settings, challenges in advocacy exist. Future directions for improving advocacy for pediatric psychologists are explored. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

12.
Mol Ecol Resour ; 20(2): 457-467, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31815343

ABSTRACT

Although environmental DNA shed from an organism is now widely used for species detection in a wide variety of contexts, mobilizing environmental DNA for management requires estimation of population size and trends in addition to assessing presence or absence. However, the efficacy of environmental-DNA-based indices of abundance for long-term population monitoring have not yet been assessed. Here we report on the relationship between six years of mark-recapture population estimates for eulachon (Thaleichthys pacificus) and "eDNA rates" which are calculated from the product of stream flow and DNA concentration. Eulachon are a culturally and biologically important anadromous fish that have significantly declined in the southern part of their range but were historically rendered into oil and traded. Both the peak eDNA rate and the area under the curve of the daily eDNA rate were highly predictive of the mark-recapture population estimate, explaining 84.96% and 92.53% of the deviance, respectively. Even in the absence of flow correction, the peak of the daily eDNA concentration explained an astonishing 89.53% while the area under the curve explained 90.74% of the deviance. These results support the use of eDNA to monitor eulachon population trends and represent a >80% cost savings over mark-recapture, which could be further increased with automated water sampling, reduced replication, and focused temporal sampling. Due to its logistical ease and affordability, eDNA sampling can facilitate monitoring a larger number of rivers and in remote locations where mark-recapture is infeasible.


Subject(s)
DNA, Environmental/genetics , Genomics/methods , Osmeriformes/genetics , Animals , Female , Genomics/economics , Male , Osmeriformes/classification , Population Density , Rivers/chemistry
13.
Mol Ecol Resour ; 19(3): 597-608, 2019 May.
Article in English | MEDLINE | ID: mdl-30592374

ABSTRACT

Pacific salmon are a keystone resource in Alaska, generating annual revenues of well over ~US$500 million/year. Due to their anadromous life history, adult spawners distribute amongst thousands of streams, posing a huge management challenge. Currently, spawners are enumerated at just a few streams because of reliance on human counters and, rarely, sonar. The ability to detect organisms by shed tissue (environmental DNA, eDNA) promises a more efficient counting method. However, although eDNA correlates generally with local fish abundances, we do not know if eDNA can accurately enumerate salmon. Here we show that daily, and near-daily, flow-corrected eDNA rate closely tracks daily numbers of returning sockeye and coho spawners and outmigrating sockeye smolts. eDNA thus promises accurate and efficient enumeration, but to deliver the most robust numbers will need higher-resolution stream-flow data, at-least-daily sampling, and a focus on species with simple life histories, since shedding rate varies amongst jacks, juveniles, and adults.


Subject(s)
DNA/genetics , DNA/isolation & purification , Genetics, Population/methods , Population Density , Salmon/growth & development , Salmon/genetics , Water/chemistry , Alaska , Animals , DNA/chemistry , Genomics/methods
14.
PLoS One ; 11(11): e0165259, 2016.
Article in English | MEDLINE | ID: mdl-27828988

ABSTRACT

Noninvasive genetic sampling is an important tool in wildlife ecology and management, typically relying on hair snaring or scat sampling techniques, but hair snaring is labor and cost intensive, and scats yield relatively low quality DNA. New approaches utilizing environmental DNA (eDNA) may provide supplementary, cost-effective tools for noninvasive genetic sampling. We tested whether eDNA from residual saliva on partially-consumed Pacific salmon (Oncorhynchus spp.) carcasses might yield suitable DNA quality for noninvasive monitoring of brown bears (Ursus arctos). We compared the efficiency of monitoring brown bear populations using both fecal DNA and salivary eDNA collected from partially-consumed salmon carcasses in Southeast Alaska. We swabbed a range of tissue types from 156 partially-consumed salmon carcasses from a midseason run of lakeshore-spawning sockeye (O. nerka) and a late season run of stream-spawning chum (O. keta) salmon in 2014. We also swabbed a total of 272 scats from the same locations. Saliva swabs collected from the braincases of salmon had the best amplification rate, followed by swabs taken from individual bite holes. Saliva collected from salmon carcasses identified unique individuals more quickly and required much less labor to locate than scat samples. Salmon carcass swabbing is a promising method to aid in efficient and affordable monitoring of bear populations, and suggests that the swabbing of food remains or consumed baits from other animals may be an additional cost-effective and valuable tool in the study of the ecology and population biology of many elusive and/or wide-ranging species.


Subject(s)
DNA/analysis , Environment , Oncorhynchus/metabolism , Predatory Behavior/physiology , Saliva/chemistry , Ursidae/physiology , Alaska , Animals , DNA/genetics , DNA/isolation & purification , Female , Genotype , Geography , Male , Oncorhynchus/classification , Polymerase Chain Reaction , Seasons , Sequence Analysis, DNA/methods , Species Specificity , Specimen Handling/economics , Specimen Handling/instrumentation , Specimen Handling/methods
15.
CNS Neurosci Ther ; 22(11): 880-893, 2016 11.
Article in English | MEDLINE | ID: mdl-27421251

ABSTRACT

BACKGROUND: Sleep disruption is a common comorbidity of pediatric pain. Consequences of pain and disrupted sleep, evidence for the pain-sleep relation, and how aspects of illness, treatment, and pharmacological pain management may contribute to or exacerbate these issues are presented. AIMS: This conceptual review explored the relation between pain and sleep in children diagnosed with chronic medical or developmental conditions. The goal of this review is to expand upon the literature by examining common themes in sleep disturbances associated with painful conditions across multiple pediatric illnesses. Populations reviewed include youth with intellectual and developmental disabilities (IDD), migraines, cystic fibrosis (CF), sickle cell disease (SCD), cancer, juvenile idiopathic arthritis (JIA), juvenile fibromyalgia (JFM), and functional gastrointestinal disorders (FGIDs). RESULTS: Consistent evidence demonstrates that children with medical or developmental conditions are more vulnerable to experiencing pain and subjective sleep complaints than healthy peers. Objective sleep concerns are common but often under-studied. Evidence of the pain-sleep relationship exists, particularly in pediatric SCD, IDD, and JIA, with a dearth of studies directly examining this relation in pediatric cancer, JFM, CF, and FGIDs. Findings suggest that assessing and treating pain and sleep disruption is important when optimizing functional outcomes. CONCLUSION: It is essential that research further examine objective sleep, elucidate the pain-sleep relationship, consider physiological and psychosocial mechanisms of this relationship, and investigate nonpharmacological interventions aimed at improving pain and sleep in vulnerable pediatric populations.


Subject(s)
Developmental Disabilities/epidemiology , Pain Management , Pain , Pediatrics , Sleep Wake Disorders/epidemiology , Comorbidity , Developmental Disabilities/complications , Humans , Pain/epidemiology , Pain/psychology , Sleep Wake Disorders/psychology , Sleep Wake Disorders/therapy
16.
PeerJ ; 3: e1157, 2015.
Article in English | MEDLINE | ID: mdl-26339539

ABSTRACT

Salmon and other anadromous fish are consumed by vertebrates with distinct life history strategies to capitalize on this ephemeral pulse of resource availability. Depending on the timing of salmon arrival, this resource may be in surplus to the needs of vertebrate consumers if, for instance, their populations are limited by food availability during other times of year. However, the life history of some consumers enables more efficient exploitation of these ephemeral resources. Bears can deposit fat and then hibernate to avoid winter food scarcity, and highly mobile consumers such as eagles, gulls, and other birds can migrate to access asynchronous pulses of salmon availability. We used camera traps on pink, chum, and sockeye salmon spawning grounds with various run times and stream morphologies, and on individual salmon carcasses, to discern potentially different use patterns among consumers. Wildlife use of salmon was highly heterogeneous. Ravens were the only avian consumer that fed heavily on pink salmon in small streams. Eagles and gulls did not feed on early pink salmon runs in streams, and only moderately at early sockeye runs, but were the dominant consumers at late chum salmon runs, particularly on expansive river flats. Brown bears used all salmon resources far more than other terrestrial vertebrates. Notably, black bears were not observed on salmon spawning grounds despite being the most frequently observed vertebrate on roads and trails. From a conservation and management perspective, all salmon species and stream morphologies are used extensively by bears, but salmon spawning late in the year are disproportionately important to eagles and other highly mobile species that are seasonally limited by winter food availability.

17.
Methods Mol Biol ; 834: 33-48, 2012.
Article in English | MEDLINE | ID: mdl-22144351

ABSTRACT

Our laboratory specializes in directed protein evolution, i.e., evolution of proteins under defined selective pressures in the laboratory. Our target genes are encoded in ColE1 plasmids to facilitate the generation of libraries in vivo. We have observed that when random mutations are not restricted to the coding sequence of the target genes, directed evolution results in a strong positive selection of plasmid origin of replication (ori) mutations. Surprisingly, this is true even during evolution of new biochemical activities, when the activity that is being selected was not originally present. The selected plasmid ori mutations are diverse and produce a range of plasmid copy numbers, suggesting a complex interplay between ori and coding mutations rather than a simple enhancement of level of expression of the target gene. Thus, plasmid dosage may contribute significantly to evolution by fine-tuning levels of activity. Here, we present examples illustrating these observations as well as our methods for efficient quantification of plasmid copy number.


Subject(s)
Directed Molecular Evolution , Gene Dosage , Plasmids/analysis , Plasmids/genetics , Proteins/genetics , Base Sequence , Escherichia coli/genetics , Escherichia coli/metabolism , Humans , Mutagenesis , Plasmids/isolation & purification , Proteins/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sequence Analysis, DNA , Transformation, Bacterial
18.
Can J Exp Psychol ; 65(3): 168-72, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21639609

ABSTRACT

Caregivers around the world sing to their infants. Infants not only prefer to listen to infant-directed singing over adult-directed singing, but infant-directed singing also serves a function, communicating affective information to preverbal infants to aid in adjusting arousal levels. Pitch variation has previously been identified as one performance feature that may help to convey the message. Earlier research has indicated that infants' pitch preferences are context dependent, suggesting that infants are tuned in to the communicative intent of infant-directed singing. However, there are several other performance-based features present in infant-directed singing that may also contribute to the affective message. The current study examined the role of context on infants' tempo preferences in sung playsongs and lullabies. Using a head-turn preference procedure, we measured 24 preverbal infants' natural preferences for foreign language playsongs and lullabies as a function of tempo. Infants showed a preference for fast over slow tempo playsongs, but no such context dependent preference was found within lullabies. Results partially support the role of tempo as a communicative feature of infant directed singing.


Subject(s)
Auditory Perception/physiology , Music/psychology , Pitch Perception/physiology , Time Perception/physiology , Canada , Child Development/physiology , Female , Humans , Infant , Language , Male , Play and Playthings
19.
Nucleic Acids Res ; 39(16): 7020-33, 2011 Sep 01.
Article in English | MEDLINE | ID: mdl-21622658

ABSTRACT

DNA polymerase I (pol I) processes RNA primers during lagging-strand synthesis and fills small gaps during DNA repair reactions. However, it is unclear how pol I and pol III work together during replication and repair or how extensive pol I processing of Okazaki fragments is in vivo. Here, we address these questions by analyzing pol I mutations generated through error-prone replication of ColE1 plasmids. The data were obtained by direct sequencing, allowing an accurate determination of the mutation spectrum and distribution. Pol I's mutational footprint suggests: (i) during leading-strand replication pol I is gradually replaced by pol III over at least 1.3 kb; (ii) pol I processing of Okazaki fragments is limited to ∼20 nt and (iii) the size of Okazaki fragments is short (∼250 nt). While based on ColE1 plasmid replication, our findings are likely relevant to other pol I replicative processes such as chromosomal replication and DNA repair, which differ from ColE1 replication mostly at the recruitment steps. This mutation footprinting approach should help establish the role of other prokaryotic or eukaryotic polymerases in vivo, and provides a tool to investigate how sequence topology, DNA damage, or interactions with protein partners may affect the function of individual DNA polymerases.


Subject(s)
DNA Polymerase I/metabolism , DNA Replication , Mutation , Plasmids/biosynthesis , Base Sequence , DNA/metabolism , DNA Footprinting , DNA Polymerase I/genetics , DNA Polymerase I/physiology , Databases, Nucleic Acid , Plasmids/chemistry
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