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Pylaiella littoralis is a brown alga with a cosmopolitan distribution. A free-living form of the alga fouls the beaches of Nahant, Massachusetts (USA). The amphipod Gammarus tigrinus is found within the floating drifts of algae. Gut contents confirmed that G. tigrinus consumed P. littoralis. Significantly, culture studies revealed that ingested P. littoralis survives and grows from fecal pellets produced by G. tigrinus. Also, inefficient grazing produced vegetative fragments that grew and survived. δ13C values for the amphipods and P. littoralis averaged −17.4 ‰ and −17.7 ‰, respectively, suggesting that G. tigrinus acquires most of its carbon from P. littoralis. [ABSTRACT FROM AUTHOR]

The first species of Rhizopogon subgenus Amylopogon identified from eastern North America is described here as Rhizopogon kretzerae Grubisha, Dowie, & Mill. sp. nov. In nature, R. kretzerae has been identified only from DNA sequences of the nuclear ribosomal internal transcribed spacer region (ITS) from mycorrhizal roots of Pinus strobus L. and Pterospora andromedea Nutt. Phylogenetic analyses and nucleotide divergence estimates of Rhizopogon ITS sequences from Pterospora roots from Quebec, Michigan, New York, and New Hampshire combined with ITS sequences of Rhizopogon subgenus Amylopogon species type collections suggest R. kretzerae is a sister-group to Rhizopogon salebrosus A.H. Sm. An absence of shared mutations, two informative sequence gaps, and 12 fixed nucleotide differences differentiate R. kretzerae and R. salebrosus. Furthermore, ITS sequences of 40 Pterospora root samples from five populations in the province of Quebec provided the first record of the distribution of R. kretzerae, a potentially rare to endangered species, in eastern Canada. Key words: Rhizopogon kretzerae, mycoheterotrophy, Pterospora andromedea, endangered species, rare fungi. La premiere espece de Rhizopogon sous-genre Amylopogon identifiee dans l'est de l'Amerique du Nord est decrite ici comme Rhizopogon kretzerae Grubisha, Dowie, & Mill. sp. nov. Dans la nature, R. kretzerae n'a ete identifie que par les sequences d'ADN de la region de l'espaceur interne transcrit (ITS) nucleaire ribosomal des racines mycorhiziennes de Pinus strobus L. et Pterospora andromedea Nutt. Les analyses phylogenetiques et l'estimation des divergences nucleotidiques des sequences de l'ITS des racines de Pterospora du Quebec, du Michigan, de l'etat de New-York et du New-Hampshire, combinees aux sequences de l'ITS de collections types de l'espece Rhizopogon sous-genre Amylopogon suggerent que R. kretzerae est un groupe-sreur de Rhizopogon salebrosus A.H. Sm. En absence de mutations partagees, deux lacunes en sequences informatives et 12 differences nucleotidiques fixes differencient R. kretzerae et R. salebrosus. De plus, les sequences des ITS de 40 echantillons de racines de Pterospora de cinq populations de la province de Quebec fournissent la premiere compilation de la distribution de R. kretzerae, une espece rare potentiellement menacee, dans l'est du Canada. [Traduit par la Redaction] Mots-cles: Rhizopogon kretzerae, mycoheterotrophie, Pterospora andromedea, especes menacees, champignons rares., Introduction Mycoheterotrophic plants rely on carbon transferred through a mycorrhizal fungus from a photosynthetic host plant. Pterospora (Monotropoideae, Ericaceae) is a monotypic mycoheterotrophic genus composed of a single species, Pterospora [...]

Examines research literature and schematic models associated with the expert-novice model in cognitive psychology. Describes a model for rendering expertise in problem solving within economics. Reports that a preliminary study indicates that this model effectively rendered both expert and novice problem solving in economics. (CFR)

Asserts that the world has become more economically interdependent but that economics instruction does not adequately provide students with this knowledge or its significance. Provides a rationale for global economic education and a set of economic concepts and generalizations that would enhance understanding of global issues. (CFR)

Premise: Mycoheterotrophic plants rely on fungi to obtain their carbon requirements. Recent experiments demonstrated the presence of endophytic bacteria associated with mycoheterotrophs. Although mycoheterotrophs show high specificity for their fungal partners, it is not known whether they also show high specificity for associated bacteria or whether the bacteria have a definite function in the symbiosis. Methods: Two 16S rRNA sequencing experiments were designed to explore endophytic microbial community composition and function in root ball fractions of the mycoheterotroph Pterospora andromedea (Ericaceae), and rhizosphere soil and control soil 5 m away from each plant. One experiment compared microbial assemblages in fractions of six plants to those in rhizosphere and control soil samples. Another experiment documented bacterial endophyte diversity in root balls of 97 plants from across North America. Results: Soil samples were similar in bacterial community structure but were significantly more diverse and less consistently structured than were bacterial communities within root balls. The proportion of endophytic bacterial species varied slightly but not their community composition despite differences in P. andromedea lineage, geography, conifer species, and fungi. Predictive metagenomic profiling of the endophytes in P. andromedea‐only root ball fractions showed many of the bacterial endophytes likely function in N‐metabolism and N‐fixation. Conclusions: Our results document a consistent and largely invariant community of endophytic bacteria in P. andromedea across biotic and abiotic environmental conditions at a continental scale. It is unknown what role these bacteria may play in the quad‐partite symbiotic network centered on P. andromedea; however, the predictive metagenomic profiling suggests a possible function in N‐metabolism or N‐fixation. Discovery of a ubiquitous community of endophytic bacteria with a putative function centered on N‐metabolism or N‐fixation could have a previously unrecognized impact on understanding of mycoheterotroph ecophysiology. [ABSTRACT FROM AUTHOR]

Significant population declines in Acropora cervicornis and A. palmata began in the 1970s and now exceed over 90%. The losses were caused by a combination of coral disease and bleaching, with possible contributions from other stressors, including pollution and predation. Reproduction in the wild by fragment regeneration and sexual recruitment is inadequate to offset population declines. Starting in 2007, the Coral Restoration Foundation™ evaluated the feasibility of outplanting A. cervicornis colonies to reefs in the Florida Keys to restore populations at sites where the species was previously abundant. Reported here are the results of 20 coral outplanting projects with each project defined as a cohort of colonies outplanted at the same time and location. Photogrammetric analysis and in situ monitoring (2007 to 2015) measured survivorship, growth, and condition of 2419 colonies. Survivorship was initially high but generally decreased after two years. Survivorship among projects based on colony counts ranged from 4% to 89% for seven cohorts monitored at least five years. Weibull survival models were used to estimate survivorship beyond the duration of the projects and ranged from approximately 0% to over 35% after five years and 0% to 10% after seven years. Growth rate averaged 10 cm/year during the first two years then plateaued in subsequent years. After four years, approximately one-third of surviving colonies were ≥ 50 cm in maximum diameter. Projects used three to sixteen different genotypes and significant differences did not occur in survivorship, condition, or growth. Restoration times for three reefs were calculated based on NOAA Recovery Plan (NRP) metrics (colony abundance and size) and the findings from projects reported here. Results support NRP conclusions that reducing stressors is required before significant population growth and recovery will occur. Until then, outplanting protects against local extinction and helps to maintain genetic diversity in the wild. [ABSTRACT FROM AUTHOR]

The 16 US history textbooks reviewed failed to incorporate economists' research on the causes of the Great Depression and consistently presented information that the economics profession has rejected. Strategies that social studies educators might adopt to improve the quality of economic analysis in textbooks is suggested. (Author/RM)