Publications by authors named "Byron Adams"

62 Publications

Occurrence and molecular characterization of on rice in Central Punjab, Pakistan.

J Nematol 2020 16;52. Epub 2021 Jan 16.

Department of Plant Pathology, University of Agriculture Faisalabad, P.O. Box 38040, Pakistan.

threatens global rice production, yet is understudied for many areas where it is cultivated. To better understand the prevalence and incidence of in central Punjab, Pakistan, we carried out field surveys of rice fields in the districts of Faisalabad and Chiniot. isolates were recovered from soil and root samples and identified on the basis of perineal patterns and rDNA ITS-based sequencing. The severity of nematode attack on rice roots and infested fields at various locations was based on galling index, root-knot nematode juveniles per root system, juveniles per 100 ml of soil, and prevalence of stylet-bearing nematodes and non-stylet-bearing nematodes. Maximum prevalence (22.5 and 27.5%) and minimum prevalence (17.5 and 20%) of was observed in Chiniot and Faisalabad, respectively. Eleven alternate host-plant species were examined in this study revealing varying degrees of infestation. ITS sequencing and phylogenetic analysis indicated that isolates from this study form a well-resolved clade with others from Asia, while another isolate falls outside of this clade in an unresolved polytomy with those from Europe and South America. Though monophyletic with the other , the isolates from Pakistan are distinguished by their high genetic variability and long branch lengths relative to the other isolates of , suggesting Pakistan as a possible ancestral area. Our results indicate that rice is severely attacked by a genetically diverse and aggressive , necessitating the development of appropriate control measures for its management in rice and other graminaceous crops.
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http://dx.doi.org/10.21307/jofnem-2020-123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8015280PMC
January 2021

Antarctic Water Tracks: Microbial Community Responses to Variation in Soil Moisture, pH, and Salinity.

Front Microbiol 2021 27;12:616730. Epub 2021 Jan 27.

Department of Biology, Brigham Young University, Provo, UT, United States.

Ice-free soils in the McMurdo Dry Valleys select for taxa able to cope with challenging environmental conditions, including extreme chemical water activity gradients, freeze-thaw cycling, desiccation, and solar radiation regimes. The low biotic complexity of Dry Valley soils makes them well suited to investigate environmental and spatial influences on bacterial community structure. Water tracks are annually wetted habitats in the cold-arid soils of Antarctica that form briefly each summer with moisture sourced from snow melt, ground ice thaw, and atmospheric deposition via deliquescence and vapor flow into brines. Compared to neighboring arid soils, water tracks are highly saline and relatively moist habitats. They represent a considerable area (∼5-10 km) of the Dry Valley terrestrial ecosystem, an area that is expected to increase with ongoing climate change. The goal of this study was to determine how variation in the environmental conditions of water tracks influences the composition and diversity of microbial communities. We found significant differences in microbial community composition between on- and off-water track samples, and across two distinct locations. Of the tested environmental variables, soil salinity was the best predictor of community composition, with members of the phylum being relatively more abundant at higher salinities and the phylum showing the opposite pattern. There was also a significant, inverse relationship between salinity and bacterial diversity. Our results suggest water track formation significantly alters dry soil microbial communities, likely influencing subsequent ecosystem functioning. We highlight how Dry Valley water tracks could be a useful model system for understanding the potential habitability of transiently wetted environments found on the surface of Mars.
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http://dx.doi.org/10.3389/fmicb.2021.616730DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7873294PMC
January 2021

Genome analysis of Plectus murrayi, a nematode from continental Antarctica.

G3 (Bethesda) 2021 Jan;11(1)

Department of Biology, Evolutionary Ecology Laboratories, and Monte L. Bean Museum, Brigham Young University, Provo, UT, USA.

Plectus murrayi is one of the most common and locally abundant invertebrates of continental Antarctic ecosystems. Because it is readily cultured on artificial medium in the laboratory and highly tolerant to an extremely harsh environment, P. murrayi is emerging as a model organism for understanding the evolutionary origin and maintenance of adaptive responses to multiple environmental stressors, including freezing and desiccation. The de novo assembled genome of P. murrayi contains 225.741 million base pairs and a total of 14,689 predicted genes. Compared to Caenorhabditis elegans, the architectural components of P. murrayi are characterized by a lower number of protein-coding genes, fewer transposable elements, but more exons, than closely related taxa from less harsh environments. We compared the transcriptomes of lab-reared P. murrayi with wild-caught P. murrayi and found genes involved in growth and cellular processing were up-regulated in lab-cultured P. murrayi, while a few genes associated with cellular metabolism and freeze tolerance were expressed at relatively lower levels. Preliminary comparative genomic and transcriptomic analyses suggest that the observed constraints on P. murrayi genome architecture and functional gene expression, including genome decay and intron retention, may be an adaptive response to persisting in a biotically simplified, yet consistently physically harsh environment.
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http://dx.doi.org/10.1093/g3journal/jkaa045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8022722PMC
January 2021

Antarctic ecosystems in transition - life between stresses and opportunities.

Biol Rev Camb Philos Soc 2020 Dec 22. Epub 2020 Dec 22.

Department of Biology and School of Global Environmental Sustainability, Colorado State University, Fort Collins, CO, U.S.A.

Important findings from the second decade of the 21st century on the impact of environmental change on biological processes in the Antarctic were synthesised by 26 international experts. Ten key messages emerged that have stakeholder-relevance and/or a high impact for the scientific community. They address (i) altered biogeochemical cycles, (ii) ocean acidification, (iii) climate change hotspots, (iv) unexpected dynamism in seabed-dwelling populations, (v) spatial range shifts, (vi) adaptation and thermal resilience, (vii) sea ice related biological fluctuations, (viii) pollution, (ix) endangered terrestrial endemism and (x) the discovery of unknown habitats. Most Antarctic biotas are exposed to multiple stresses and considered vulnerable to environmental change due to narrow tolerance ranges, rapid change, projected circumpolar impacts, low potential for timely genetic adaptation, and migration barriers. Important ecosystem functions, such as primary production and energy transfer between trophic levels, have already changed, and biodiversity patterns have shifted. A confidence assessment of the degree of 'scientific understanding' revealed an intermediate level for most of the more detailed sub-messages, indicating that process-oriented research has been successful in the past decade. Additional efforts are necessary, however, to achieve the level of robustness in scientific knowledge that is required to inform protection measures of the unique Antarctic terrestrial and marine ecosystems, and their contributions to global biodiversity and ecosystem services.
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http://dx.doi.org/10.1111/brv.12679DOI Listing
December 2020

Three new species of Longior Travassos Kloss, 1958 (Nematoda: Thelastomatoidea: Hystrignathidae) parasites of passalid beetles (Coleoptera: Passalidae) from Dominican Republic, Mexico and Colombia.

Zootaxa 2020 Nov 9;4877(1):zootaxa.4877.1.5. Epub 2020 Nov 9.

Instituto de Ecología y Sistemática, Carretera Varona 11835 e/ Oriente y Lindero, La Habana 19, CP 11900, Calabazar, Boyeros, La Habana, Cuba Department of Environmental Biology, College of Bioscience  Biotechnology, Chubu University, 1200 Matsumoto, Kasugai, Aichi 487-8501, Japan.

Three new species of the genus Longior Travassos Kloss, 1958 are described and illustrated, namely L. surieli n. sp. in Antillanax dominicanus (Doesburg, 1953) from the Dominican Republic, L. lamothei n. sp. in Passalus punctiger Le Peletier Serville, 1825 from Mexico and Colombia and L. zumpimito n. sp. in P. punctatostriatus Percheron, 1835 from Mexico. These constitute the first records of the genus Longior for the aforementioned countries, rising to nine species in the genus. The new species can be differentiated mainly by the length of their body, oesophagus and tail in both sexes, the extension of the lateral alae in the females and the morphology of the cephalic and posterior end in the males. The molecular phylogeny of the new taxa is inferred by the 28S and 18S rDNA and they form a monophyletic clade with other Longior species. The phylogeny of Longior and that of their passalid hosts reveal coevolutionary relationships. These patterns suggest that the phylogeny of Longior species is probably strongly influenced by the evolutionary trajectories of their passalid hosts.
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http://dx.doi.org/10.11646/zootaxa.4877.1.5DOI Listing
November 2020

The Association Between Threat and Politics Depends on the Type of Threat, the Political Domain, and the Country.

Pers Soc Psychol Bull 2021 Feb 26;47(2):324-343. Epub 2020 Aug 26.

Tilburg University, The Netherlands.

Theories link threat with right-wing political beliefs. We use the World Values Survey (60,378 participants) to explore how six types of threat (e.g., economic, violence, and surveillance) are associated with multiple political beliefs (e.g., cultural, economic, and ideological identification) in 56 countries/territories. Multilevel models with individuals nested in countries revealed that the threat-political belief association depends on the type of threat, the type of political belief, and the country. Economic-related threats tended to be associated with more left-wing economic political beliefs and violence-related threats tended to be associated with more cultural right-wing beliefs, but there were exceptions to this pattern. Additional analyses revealed that the associations between threat and political beliefs were different across countries. However, our analyses identified few country characteristics that could account for these cross-country differences. Our findings revealed that political beliefs and perceptions of threat are linked, but that the relationship is not simple.
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http://dx.doi.org/10.1177/0146167220946187DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7859575PMC
February 2021

Genetic diversity of soil invertebrates corroborates timing estimates for past collapses of the West Antarctic Ice Sheet.

Proc Natl Acad Sci U S A 2020 09 24;117(36):22293-22302. Epub 2020 Aug 24.

School of Science, University of Waikato, Hamilton 3240, New Zealand.

During austral summer field seasons between 1999 and 2018, we sampled at 91 locations throughout southern Victoria Land and along the Transantarctic Mountains for six species of endemic microarthropods (Collembola), covering a latitudinal range from 76.0°S to 87.3°S. We assembled individual mitochondrial cytochrome oxidase subunit 1 (COI) sequences ( = 866) and found high levels of sequence divergence at both small (<10 km) and large (>600 km) spatial scales for four of the six Collembola species. We applied molecular clock estimates and assessed genetic divergences relative to the timing of past glacial cycles, including collapses of the West Antarctic Ice Sheet (WAIS). We found that genetically distinct lineages within three species have likely been isolated for at least 5.54 My to 3.52 My, while the other three species diverged more recently (<2 My). We suggest that Collembola had greater dispersal opportunities under past warmer climates, via flotation along coastal margins. Similarly increased opportunities for dispersal may occur under contemporary climate warming scenarios, which could influence the genetic structure of extant populations. As Collembola are a living record of past landscape evolution within Antarctica, these findings provide biological evidence to support geological and glaciological estimates of historical WAIS dynamics over the last 5 My.
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http://dx.doi.org/10.1073/pnas.2007925117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7486705PMC
September 2020

Shotgun metagenomics reveal a diverse assemblage of protists in a model Antarctic soil ecosystem.

Environ Microbiol 2020 11 15;22(11):4620-4632. Epub 2020 Sep 15.

Department of Biology, Brigham Young University, Provo, UT, USA.

The soils of the McMurdo Dry Valleys (MDV) of Antarctica are established models for understanding fundamental processes in soil ecosystem functioning (e.g. ecological tipping points, community structuring and nutrient cycling) because the extreme physical environment drastically reduces biodiversity and ecological complexity. Understanding the functioning of MDV soils requires in-depth knowledge of the diversity of MDV soil species. Protists, which contribute significantly to soil ecosystem functioning worldwide, remain poorly characterized in the MDV. To better assess the diversity of MDV protists, we performed shotgun metagenomics on 18 sites representing a variety of landscape features and edaphic variables. Our results show MDV soil protists are diverse at both the genus (155 of 281 eukaryote genera) and family (120) levels, but comprise only 6% of eukaryotic reads. Protists are structured by moisture, total N and distance from the local coast and possess limited richness in arid (< 5% moisture) and at high elevation sites, known drivers of communities in the MDV. High relative diversity and broad distribution of protists in our study promotes these organisms as key members of MDV soil microbiomes and the MDV as a useful system for understanding the contribution of soil protists to the structure of soil microbiomes.
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http://dx.doi.org/10.1111/1462-2920.15198DOI Listing
November 2020

First record of native entomopathogenic nematodes from Montana agroecosystems.

J Nematol 2020 ;52:1-11

Department of Research Centers, Western Triangle Agricultural Research Center, Montana State University , 9546 Old Shelby Rd., P.O. Box 656, Conrad, MT 59425 ; USDA-ARS, Southern Insect Management Research Unit, 141 Experiment Station Road, P.O. Box 346, Stoneville, MS 38776.

A total of 30 different agricultural fields in the Golden Triangle Region of Montana, USA were surveyed, and 150 soil samples were evaluated for the presence of entomopathogenic nematodes (EPNs). The authors isolated EPNs from 10% of the collected samples. The recovered isolates were identified as and by using morphological and molecular analysis. was found from two fields, Kalispell ( 1) and Choteau ( 2). (1 and 2) differed significantly from each other in terms of morphological characters for infective juveniles (distance from anterior end to excretory pore and nerve ring) and 1st generation males (body length, spicule length, gubernaculum length, oesophagus, tail, and anal body diameter). 2 and were recovered from the same field in Choteau. All these species were recovered from wheat fields with sandy clay loam and loam soils with 3.3 to 3.4% organic matter content and pH 8.

A total of 30 different agricultural fields in the Golden Triangle Region of Montana, USA were surveyed, and 150 soil samples were evaluated for the presence of entomopathogenic nematodes (EPNs). The authors isolated EPNs from 10% of the collected samples. The recovered isolates were identified as and by using morphological and molecular analysis. was found from two fields, Kalispell ( 1) and Choteau ( 2). (1 and 2) differed significantly from each other in terms of morphological characters for infective juveniles (distance from anterior end to excretory pore and nerve ring) and 1st generation males (body length, spicule length, gubernaculum length, oesophagus, tail, and anal body diameter). 2 and were recovered from the same field in Choteau. All these species were recovered from wheat fields with sandy clay loam and loam soils with 3.3 to 3.4% organic matter content and pH 8.
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http://dx.doi.org/10.21307/jofnem-2020-060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7366840PMC
January 2020

Country-level correlates of the Dark Triad traits in 49 countries.

J Pers 2020 12 1;88(6):1252-1267. Epub 2020 Jul 1.

Taras Shevchenko National University of Kyiv, Kyiv, Ukraine.

Objectives: The Dark Triad traits (i.e., narcissism, psychopathy, Machiavellianism) capture individual differences in aversive personality to complement work on other taxonomies, such as the Big Five traits. However, the literature on the Dark Triad traits relies mostly on samples from English-speaking (i.e., Westernized) countries. We broadened the scope of this literature by sampling from a wider array of countries.

Method: We drew on data from 49 countries (N = 11,723; 65.8% female; Age  = 21.53) to examine how an extensive net of country-level variables in economic status (e.g., Human Development Index), social relations (e.g., gender equality), political orientations (e.g., democracy), and cultural values (e.g., embeddedness) relate to country-level rates of the Dark Triad traits, as well as variance in the magnitude of sex differences in them.

Results: Narcissism was especially sensitive to country-level variables. Countries with more embedded and hierarchical cultural systems were more narcissistic. Also, sex differences in narcissism were larger in more developed societies: Women were less likely to be narcissistic in developed (vs. less developed) countries.

Conclusions: We discuss the results based on evolutionary and social role models of personality and sex differences. That higher country-level narcissism was more common in less developed countries, whereas sex differences in narcissism were larger in more developed countries, is more consistent with evolutionary than social role models.
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http://dx.doi.org/10.1111/jopy.12569DOI Listing
December 2020

Structure of Dark Triad Dirty Dozen Across Eight World Regions.

Assessment 2020 Jun 2:1073191120922611. Epub 2020 Jun 2.

Universidad Catolica del Norte, Antofagasta, Chile.

The Dark Triad (i.e., narcissism, psychopathy, Machiavellianism) has garnered intense attention over the past 15 years. We examined the structure of these traits' measure-the Dark Triad Dirty Dozen (DTDD)-in a sample of 11,488 participants from three W.E.I.R.D. (i.e., North America, Oceania, Western Europe) and five non-W.E.I.R.D. (i.e., Asia, Middle East, non-Western Europe, South America, sub-Saharan Africa) world regions. The results confirmed the measurement invariance of the DTDD across participants' sex in all world regions, with men scoring higher than women on all traits (except for psychopathy in Asia, where the difference was not significant). We found evidence for metric (and partial scalar) measurement invariance within and between W.E.I.R.D. and non-W.E.I.R.D. world regions. The results generally support the structure of the DTDD.
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http://dx.doi.org/10.1177/1073191120922611DOI Listing
June 2020

A global database of soil nematode abundance and functional group composition.

Sci Data 2020 03 26;7(1):103. Epub 2020 Mar 26.

Department of Environmental Systems Science, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland.

As the most abundant animals on earth, nematodes are a dominant component of the soil community. They play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns.
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http://dx.doi.org/10.1038/s41597-020-0437-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7099023PMC
March 2020

Development of an Evolutionary Tree Concept Inventory.

J Microbiol Biol Educ 2019 30;20(2). Epub 2019 Aug 30.

Department of Biology, Brigham Young University, Provo, UT 84602.

Despite the importance of tree-thinking and evolutionary trees to biology, no appropriately developed concept inventory exists to measure student understanding of these important concepts. To address this need, we developed a multiple-choice concept inventory consisting of 24 pairs of items, and we provide evidence to support its use among undergraduate students. A set of learning outcomes was developed to guide the creation of the concept inventory. The learning outcomes, student interviews, and student responses were used to develop and revise inventory items. Supporting evidence was gathered from traditional item analysis, exploratory factor analysis, confirmatory factor analysis, traditional reliability analyses, and comparisons to alternative assessments. Appropriate implementation and utility of the concept inventory are discussed.
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http://dx.doi.org/10.1128/jmbe.v20i2.1700DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6713480PMC
August 2019

Soil nematode abundance and functional group composition at a global scale.

Nature 2019 08 24;572(7768):194-198. Epub 2019 Jul 24.

Department of Environmental Systems Science, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland.

Soil organisms are a crucial part of the terrestrial biosphere. Despite their importance for ecosystem functioning, few quantitative, spatially explicit models of the active belowground community currently exist. In particular, nematodes are the most abundant animals on Earth, filling all trophic levels in the soil food web. Here we use 6,759 georeferenced samples to generate a mechanistic understanding of the patterns of the global abundance of nematodes in the soil and the composition of their functional groups. The resulting maps show that 4.4 ± 0.64 × 10 nematodes (with a total biomass of approximately 0.3 gigatonnes) inhabit surface soils across the world, with higher abundances in sub-Arctic regions (38% of total) than in temperate (24%) or tropical (21%) regions. Regional variations in these global trends also provide insights into local patterns of soil fertility and functioning. These high-resolution models provide the first steps towards representing soil ecological processes in global biogeochemical models and will enable the prediction of elemental cycling under current and future climate scenarios.
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http://dx.doi.org/10.1038/s41586-019-1418-6DOI Listing
August 2019

Corrigendum: Stoichiometric Shifts in Soil C:N:P Promote Bacterial Taxa Dominance, Maintain Biodiversity, and Deconstruct Community Assemblages.

Front Microbiol 2019 12;10:391. Epub 2019 Mar 12.

Evolutionary Ecology Laboratories, and Monte L. Bean Museum, Department of Biology, Brigham Young University, Provo, UT, United States.

[This corrects the article DOI: 10.3389/fmicb.2018.01401.].
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http://dx.doi.org/10.3389/fmicb.2019.00391DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423447PMC
March 2019

Nematodes in a polar desert reveal the relative role of biotic interactions in the coexistence of soil animals.

Commun Biol 2019 15;2:63. Epub 2019 Feb 15.

Department of Biology, Evolutionary Ecology Laboratories, and the Monte L. Bean Museum, Brigham Young University, Provo, UT, 84602, USA.

Abiotic factors are major determinants of soil animal distributions and their dominant role is pronounced in extreme ecosystems, with biotic interactions seemingly playing a minor role. We modelled co-occurrence and distribution of the three nematode species that dominate the soil food web of the McMurdo Dry Valleys (Antarctica). Abiotic factors, other biotic groups, and autocorrelation all contributed to structuring nematode species distributions. However, after removing their effects, we found that the presence of the most abundant nematode species greatly, and negatively, affected the probability of detecting one of the other two species. We observed similar patterns in relative abundances for two out of three pairs of species. Harsh abiotic conditions alone are insufficient to explain contemporary nematode distributions whereas the role of negative biotic interactions has been largely underestimated in soil. The future challenge is to understand how the effects of global change on biotic interactions will alter species coexistence.
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http://dx.doi.org/10.1038/s42003-018-0260-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6377602PMC
April 2020

Biotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem.

Commun Biol 2019 15;2:62. Epub 2019 Feb 15.

School of Science, University of Waikato, Hamilton, 3240, New Zealand.

Abiotic and biotic factors control ecosystem biodiversity, but their relative contributions remain unclear. The ultraoligotrophic ecosystem of the Antarctic Dry Valleys, a simple yet highly heterogeneous ecosystem, is a natural laboratory well-suited for resolving the abiotic and biotic controls of community structure. We undertook a multidisciplinary investigation to capture ecologically relevant biotic and abiotic attributes of more than 500 sites in the Dry Valleys, encompassing observed landscape heterogeneities across more than 200 km. Using richness of autotrophic and heterotrophic taxa as a proxy for functional complexity, we linked measured variables in a parsimonious yet comprehensive structural equation model that explained significant variations in biological complexity and identified landscape-scale and fine-scale abiotic factors as the primary drivers of diversity. However, the inclusion of linkages among functional groups was essential for constructing the best-fitting model. Our findings support the notion that biotic interactions make crucial contributions even in an extremely simple ecosystem.
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http://dx.doi.org/10.1038/s42003-018-0274-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6377621PMC
April 2020

Concentrations of pharmaceuticals and other micropollutants in groundwater downgradient from large on-site wastewater discharges.

PLoS One 2018 7;13(11):e0206004. Epub 2018 Nov 7.

Minnesota Pollution Control Agency, St. Paul, Minnesota, United States of America.

Large subsurface treatment systems (LSTS) and rapid infiltration basins (RIB) are preferred onsite wastewater treatments compared to direct discharge of treated wastewater to streams and adjacent facilities. Discharge of these wastewater treatments may result in contaminant loading to aquifers that also serve as drinking water sources downgradient from the discharge site. Until recently, few studies have characterized the contribution of micropollutants (e.g. pharmaceuticals, fragrances, flame retardants, etc.) to receiving aquifers. We conducted a pilot project to characterize the occurrence of micropollutants in groundwater downgradient from 7 on-site treatment systems in Minnesota, USA: 5 community LSTS and 2 municipal RIB. One downgradient monitoring well was sampled three times at each facility over one year. Of 223 micropollutants analyzed, 35 were detected. Total sample concentrations ranged from 90 to 4,039 ng/L. Sulfamethoxazole (antibiotic) was detected in all samples at concentrations from 7 to 965 ng/L. Other pharmaceuticals (0.12-1,000 ng/L), organophosphorus flame retardants (10-500 ng/L), and other anthropogenic chemicals (4-775 ng/L) were also detected. The numbers and concentrations of micropollutants detected were inversely related to dissolved oxygen and depth to water. Ratios of pharmaceutical concentrations to human-health screening values were <0.10 for most samples. However, concentrations of carbamazepine and sulfamethoxazole exceeded screening values at two sites. Study results illustrate that large on-site wastewater systems designed to discharge to permeable soil or shallow groundwater effectively deliver pharmaceuticals and other micropollutants to groundwater aquifers and could contribute micropollutants to drinking water via water supply wells.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0206004PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221291PMC
April 2019

Morphological and molecular characterization of Coynema poeyi (Coy, García Álvarez, 1993) (Oxyuridomorpha: Hystrignathidae) from Antillanax pertyi (Kaup, 1869) (Coleoptera: Passalidae) from Cuba and new locality records for the species.

Zootaxa 2018 Oct 8;4497(1):29-40. Epub 2018 Oct 8.

Instituto de Ecología y Sistemática, Carretera Varona 11835 e/ Oriente y Lindero, La Habana 19, CP 11900, Calabazar, Boyeros, La Habana, Cuba.

Coynema poeyi (Coy, García Álvarez, 1993) (Oxyuridomorpha: Hystrignathidae) is redescribed and illustrated with the aid of SEM. New features of the cephalic end of both sexes and copulatory papillae pattern of the males were observed and the generic diagnosis is emended in order to include such features. New locality records are given. The phylogenetic position of the species is inferred on the basis of the D2-D3 segment of the LSU rDNA. C. poeyi is located basal in a monophyletic clade formed by other hystrignathids: two species of Longior Travassos Kloss, 1958 and Hystrignathus sp.
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http://dx.doi.org/10.11646/zootaxa.4497.1.2DOI Listing
October 2018

Stoichiometric Shifts in Soil C:N:P Promote Bacterial Taxa Dominance, Maintain Biodiversity, and Deconstruct Community Assemblages.

Front Microbiol 2018 3;9:1401. Epub 2018 Jul 3.

Evolutionary Ecology Laboratories, and Monte L. Bean Museum, Department of Biology, Brigham Young University, Provo, UT, United States.

Imbalances in C:N:P supply ratios may cause bacterial resource limitations and constrain biogeochemical processes, but the importance of shifts in soil stoichiometry are complicated by the nearly limitless interactions between an immensely rich species pool and a multiple chemical resource forms. To more clearly identify the impact of soil C:N:P on bacteria, we evaluated the cumulative effects of single and coupled long-term nutrient additions (i.e., C as mannitol, N as equal concentrations NH and NO, and P as NaPO) and water on communities in an Antarctic polar desert, Taylor Valley. Untreated soils possessed relatively low bacterial diversity, simplified organic C sources due to the absence of plants, limited inorganic N, and excess soil P potentially attenuating links between C:N:P. After 6 years of adding resources, an alleviation of C and N colimitation allowed one rare Micrococcaceae, an species, to dominate, comprising 47% of the total community abundance and elevating soil respiration by 136% relative to untreated soils. The addition of N alone reduced C:N ratios, elevated bacterial richness and diversity, and allowed rare taxa relying on ammonium and nitrite for metabolism to become more abundant [e.g., nitrite oxidizing species (Nitrosomonadaceae), denitrifiers utilizing nitrite (Gemmatimonadaceae) and members of Rhodobacteraceae with a high affinity for ammonium]. Based on community co-occurrence networks, lower C:P ratios in soils following P and CP additions created more diffuse and less connected communities by disrupting 73% of species interactions and selecting for taxa potentially exploiting abundant P. Unlike amended nutrients, water additions alone elicited no lasting impact on communities. Our results suggest that as soils become nutrient rich a wide array of outcomes are possible from species dominance and the deconstruction of species interconnectedness to the maintenance of biodiversity.
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http://dx.doi.org/10.3389/fmicb.2018.01401DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6037766PMC
July 2018

Morphological examination and phylogenetic analysis clarify the taxonomic status of Cuban Longior Travassos Kloss, 1958 (Nematoda: Thelastomatoidea: Hystrignathidae).

Zootaxa 2018 Mar 22;4399(4):521-542. Epub 2018 Mar 22.

Instituto de Ecología y Sistemática, Carretera Varona 11835 e/ Oriente y Lindero, La Habana 19, CP 11900, Calabazar, Boyeros, La Habana, Cuba.

The status of Longior alius García Coy, 1994 (Nematoda: Thelastomatoidea: Hystrignathidae) is discussed on the basis of new material obtained from its type host Antillanax pertyi (Kaup, 1869) (Coleoptera: Passalidae) from Limonar, Guantánamo province, Cuba, near the type locality. Based on morphological and molecular studies L. alius is considered synonymous with L. longior Morffe García, 2011. L. longior and L. similis Morffe, García Ventosa, 2009 are redescribed and illustrated with the aid of SEM. New locality records for both species are given. The conspecificity of females and males of both species is supported by comparison of the D2-D3 segment of the 28S LSU rDNA. The inter-specific differences and phylogenetic position of L. longior and L. similis are discussed.
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http://dx.doi.org/10.11646/zootaxa.4399.4.3DOI Listing
March 2018

When There Are Only Minorities: Identity and In-Group / Out-Group Orientations of Emerging Adults in Four South African Ethnocultural Groups.

Emerg Adulthood 2018 Feb 22;6(1):7-16. Epub 2018 Jan 22.

University of the Free State, Bloemfontein, South Africa.

Intergroup relation perspectives stem from research in Western contexts with clear distinctions between the dominant and nondominant groups. In South Africa, with at least 13 different cultural groups and 11 official languages, no group is dominant in all life spheres. We examine the relationship between identity and in-/out-group orientation across Black-Zulu, Coloured (mixed racial ancestry), Indian, and White-Afrikaans emerging adults ( = 390; 75% females, = 19.97 years, = 2.44). Results indicate that personal identity for all groups and ethnic identity for Black-Zulu, Indian, and White-Afrikaans emerging adults were important for intergroup relations. Black-Zulu, Coloured, and Indian emerging adults distinguish themselves less from others, whereas White-Afrikaans emerging adults are less open to others. Ultimately, the complexity of intergroup relations in South Africa has implications for the effective transformation interventions needed to counter experiences of threat and make group boundaries more flexible for emerging adults.
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http://dx.doi.org/10.1177/2167696817752755DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5836528PMC
February 2018

The mental health continuum-short form: The structure and application for cross-cultural studies-A 38 nation study.

J Clin Psychol 2018 06 30;74(6):1034-1052. Epub 2018 Jan 30.

University of Leicester, United Kingdom.

Objective: The Mental Health Continuum-Short Form (MHC-SF) is a brief scale measuring positive human functioning. The study aimed to examine the factor structure and to explore the cross-cultural utility of the MHC-SF using bifactor models and exploratory structural equation modelling.

Method: Using multigroup confirmatory analysis (MGCFA) we examined the measurement invariance of the MHC-SF in 38 countries (university students, N = 8,066; 61.73% women, mean age 21.55 years).

Results: MGCFA supported the cross-cultural replicability of a bifactor structure and a metric level of invariance between student samples. The average proportion of variance explained by the general factor was high (ECV = .66), suggesting that the three aspects of mental health (emotional, social, and psychological well-being) can be treated as a single dimension of well-being.

Conclusion: The metric level of invariance offers the possibility of comparing correlates and predictors of positive mental functioning across countries; however, the comparison of the levels of mental health across countries is not possible due to lack of scalar invariance. Our study has preliminary character and could serve as an initial assessment of the structure of the MHC-SF across different cultural settings. Further studies on general populations are required for extending our findings.
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http://dx.doi.org/10.1002/jclp.22570DOI Listing
June 2018

Detecting sulfamethoxazole and carbamazepine in groundwater: Is ELISA a reliable screening tool?

Environ Pollut 2018 Mar 1;234:420-428. Epub 2017 Dec 1.

Minnesota Pollution Control Agency, 520 Lafayette Road North, St. Paul, MN 55155, USA.

In recent years, numerous studies have reported the prevalence of organic micropollutants in natural waters. There is an increasing interest in assessing the occurrence and transport of these contaminants in groundwater because a large number of people in the United States rely on groundwater for their drinking water. However, commonly used mass-spectrometry-based analytical methods are expensive and time-consuming. The enzyme-linked immunosorbent assay (ELISA) method offers an inexpensive analytical alternative that provides semi-quantitative results in a relatively quick timeframe. We investigated the use of ELISA for two commonly detected micropollutants, sulfamethoxazole (SMX) and carbamazepine (CBZ), in groundwater collected as part of two different studies, one in Minnesota and the other in Iowa. The ELISA results were compared with two mass-spectrometry-based methods: (1) direct aqueous injection-high performance liquid chromatography/tandem mass spectrometry (HPLC) and (2) online solid-phase extraction with liquid chromatography/electrospray ionization-mass spectrometry (SPE LC). Differences in SMX and CBZ observations between ELISA and both HPLC and SPE LC were analyzed using the Paired Prentice-Wilcoxon test. Estimates of bias and limits of agreement between paired observations also were calculated. The SMX determinations by ELISA yielded results that were 30 and 14% greater than HPLC and SPE LC, respectively. The CBZ determinations by ELISA yielded results that were 25 and 9% greater than HPLC and SPE LC, respectively. The ELISA determinations were in presence-absence agreement with HPLC for 83% of samples for SMX and CBZ; and with SPE LC for 76 and 80% of samples for SMX and CBZ, respectively. Results indicate that ELISA for SMX and CBZ is a reliable and cost effective screening-tool alternative to more commonly used mass spectrometry-based analytical methods.
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http://dx.doi.org/10.1016/j.envpol.2017.11.065DOI Listing
March 2018

An Integrated Approach to Bias in a Longitudinal Survey in the United Kingdom: Assessing Construct, Method, and Item Bias in the General Health Questionnaire (GHQ-12).

Assessment 2019 10 9;26(7):1194-1206. Epub 2017 Nov 9.

Tilburg University, Tilburg, The Netherlands.

Construct, method, and item bias are three levels of measurement bias (i.e., internal bias) essential for valid group comparisons. While many studies often focus on only one level of bias, an integrated perspective on bias is still missing, especially in longitudinal designs. The aim of this study is to address bias in an integrated manner, using four waves of data in the U.K. Longitudinal Household Panel Survey. Responses to the General Health Questionnaire (GHQ-12) from natives and two generations of immigrants were used to analyze the three levels of bias. While the basic structure of the GHQ-12 was stable across groups and time, item and method bias decreased with repeated administrations. Results were confirmed with a sensitivity test. The integrated results allowed for a distinction between temporal sources of bias that became smaller over time and sources affecting valid comparisons persistently. We discuss the implications for mental health assessment.
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http://dx.doi.org/10.1177/1073191117739979DOI Listing
October 2019

Decadal ecosystem response to an anomalous melt season in a polar desert in Antarctica.

Nat Ecol Evol 2017 Sep 7;1(9):1334-1338. Epub 2017 Aug 7.

Department of Biology and School of Global Environmental Sustainability, Colorado State University, Fort Collins, CO, 80523, USA.

Amplified climate change in polar regions is significantly altering regional ecosystems, yet there are few long-term records documenting these responses. The McMurdo Dry Valleys (MDV) cold desert ecosystem is the largest ice-free area of Antarctica, comprising soils, glaciers, meltwater streams and permanently ice-covered lakes. Multi-decadal records indicate that the MDV exhibited a distinct ecosystem response to an uncharacteristic austral summer and ensuing climatic shift. A decadal summer cooling phase ended in 2002 with intense glacial melt ('flood year')-a step-change in water availability triggering distinct changes in the ecosystem. Before 2002, the ecosystem exhibited synchronous behaviour: declining stream flow, decreasing lake levels, thickening lake ice cover, decreasing primary production in lakes and streams, and diminishing soil secondary production. Since 2002, summer air temperatures and solar flux have been relatively consistent, leading to lake level rise, lake ice thinning and elevated stream flow. Biological responses varied; one stream cyanobacterial mat type immediately increased production, but another stream mat type, soil invertebrates and lake primary productivity responded asynchronously a few years after 2002. This ecosystem response to a climatic anomaly demonstrates differential biological community responses to substantial perturbations, and the mediation of biological responses to climate change by changes in physical ecosystem properties.
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http://dx.doi.org/10.1038/s41559-017-0253-0DOI Listing
September 2017

Decoupled responses of soil bacteria and their invertebrate consumer to warming, but not freeze-thaw cycles, in the Antarctic Dry Valleys.

Ecol Lett 2017 10 10;20(10):1242-1249. Epub 2017 Aug 10.

Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA.

Altered temperature profiles resulting in increased warming and freeze-thaw cycle (FTC) frequency pose great ecological challenges to organisms in alpine and polar ecosystems. We performed a laboratory microcosm experiment to investigate how temperature variability affects soil bacterial cell numbers, and abundance and traits of soil microfauna (the microbivorous nematode Scottnema lindsayae) from McMurdo Dry Valleys, Antarctica. FTCs and constant freezing shifted nematode body size distribution towards large individuals, driven by higher mortality among smaller individuals. FTCs reduced both bacterial and nematode abundance, but bacterial cell numbers also declined under warming, demonstrating decoupled consumer-prey responses. We predict that higher occurrence of FTCs in cold ecosystems will select for large body size within soil microinvertebrates and overall reduce their abundance. In contrast, warm temperatures without FTCs could lead to divergent responses in soil bacteria and their microinvertebrate consumers, potentially affecting energy and nutrient transfer rates in soil food webs of cold ecosystems.
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http://dx.doi.org/10.1111/ele.12819DOI Listing
October 2017

Promoting the Multidimensional Character of Scientific Reasoning.

J Microbiol Biol Educ 2017 Apr 21;18(1). Epub 2017 Apr 21.

Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602.

This study reports part of a long-term program to help students improve scientific reasoning using higher-order cognitive tasks set in the discipline of cell biology. This skill was assessed using problems requiring the construction of valid conclusions drawn from authentic research data. We report here efforts to confirm the hypothesis that data interpretation is a complex, multifaceted exercise. Confirmation was obtained using a statistical treatment showing that various such problems rank students differently-each contains a unique set of cognitive challenges. Additional analyses of performance results have allowed us to demonstrate that individuals differ in their capacity to navigate five independent generic elements that constitute successful data interpretation: biological context, connection to course concepts, experimental protocols, data inference, and integration of isolated experimental observations into a coherent model. We offer these aspects of scientific thinking as a "data analysis skills inventory," along with usable sample problems that illustrate each element. Additionally, we show that this kind of reasoning is rigorous in that it is difficult for most novice students, who are unable to intuitively implement strategies for improving these skills. Instructors armed with knowledge of the specific challenges presented by different types of problems can provide specific helpful feedback during formative practice. The use of this instructional model is most likely to require changes in traditional classroom instruction.
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http://dx.doi.org/10.1128/jmbe.v18i1.1272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5410765PMC
April 2017

Genetic diversity among populations of Antarctic springtails (Collembola) within the Mackay Glacier ecotone.

Genome 2016 Sep 4;59(9):762-70. Epub 2016 May 4.

d Evolutionary Ecology Laboratories, Department of Biology, Brigham Young University, Provo, UT 84602, USA.

Climate changes are likely to have major influences on the distribution and abundance of Antarctic terrestrial biota. To assess arthropod distribution and diversity within the Ross Sea region, we examined mitochondrial DNA (COI) sequences for three currently recognized species of springtail (Collembola) collected from sites in the vicinity, and to the north of, the Mackay Glacier (77°S). This area acts as a transition between two biogeographic regions (northern and southern Victoria Land). We found populations of highly divergent individuals (5%-11.3% intraspecific sequence divergence) for each of the three putative springtail species, suggesting the possibility of cryptic diversity. Based on molecular clock estimates, these divergent lineages are likely to have been isolated for 3-5 million years. It was during this time that the Western Antarctic Ice Sheet (WAIS) was likely to have completely collapsed, potentially facilitating springtail dispersal via rafting on running waters and open seaways. The reformation of the WAIS would have isolated newly established populations, with subsequent dispersal restricted by glaciers and ice-covered areas. Given the currently limited distributions for these genetically divergent populations, any future changes in species' distributions can be easily tracked through the DNA barcoding of springtails from within the Mackay Glacier ecotone.
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http://dx.doi.org/10.1139/gen-2015-0194DOI Listing
September 2016

Natural Selection in Virulence Genes of Francisella tularensis.

J Mol Evol 2016 06 13;82(6):264-78. Epub 2016 May 13.

Department of Biology, Brigham Young University, Provo, UT, 84602, USA.

A fundamental tenet of evolution is that alleles that are under negative selection are often deleterious and confer no evolutionary advantage. Negatively selected alleles are removed from the gene pool and are eventually extinguished from the population. Conversely, alleles under positive selection do confer an evolutionary advantage and lead to an increase in the overall fitness of the organism. These alleles increase in frequency until they eventually become fixed in the population. Francisella tularensis is a zoonotic pathogen and a potential biothreat agent. The most virulent type of F. tularensis, Type A, is distributed across North America with Type A.I occurring mainly in the east and Type A.II appearing mainly in the west. F. tularensis is thought to be a genome in decay (losing genes) because of the relatively large number of pseudogenes present in its genome. We hypothesized that the observed frequency of gene loss/pseudogenes may be an artifact of evolution in response to a changing environment, and that genes involved in virulence should be under strong positive selection. To test this hypothesis, we sequenced and compared whole genomes of Type A.I and A.II isolates. We analyzed a subset of virulence and housekeeping genes from several F. tularensis subspecies genomes to ascertain the presence and extent of positive selection. Eleven previously identified virulence genes were screened for positive selection along with 10 housekeeping genes. Analyses of selection yielded one housekeeping gene and 7 virulence genes which showed significant evidence of positive selection at loci implicated in cell surface structures and membrane proteins, metabolism and biosynthesis, transcription, translation and cell separation, and substrate binding and transport. Our results suggest that while the loss of functional genes through disuse could be accelerated by negative selection, the genome decay in Francisella could also be the byproduct of adaptive evolution driven by complex interactions between host, pathogen, and thier environment, as evidenced by several of its virulence genes which are undergoing strong, positive selection.
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http://dx.doi.org/10.1007/s00239-016-9743-yDOI Listing
June 2016