Nomenclature and taxonomy of Croton glabellus L. (Euphorbiaceae), a widespread Caribbean species

The application of the names Croton glabellus, C. lucidus, and Phyllanthus glabellus has been confusing since the earliest publications that used them. After a thorough review of these publications and corresponding herbarium specimens, we clarify the nomenclatural confusion surrounding these names and their taxonomy. We identify a new name, Phyllanthus glabellus Fawc. & Rendle, that was inadvertently made. We make the new combination Croton glabellus subsp. polytrichus, and we designate lectotypes for Astrocasia tremula, Croton subsect. Astraeopsis, C. glandulifer, C. lucidus var. polytrichus, and C. spicatus.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146901/1/tax605029.pd

A revised infrageneric classification and molecular phylogeny of New World Croton (Euphorbiaceae)

Croton (Euphorbiaceae) is a large and diverse group of plants that is most species‐rich in the tropics. We update the infrageneric classification of the New World species of Croton with new evidence from phylogenetic analyses of DNA sequence data from all three genomes. The relationships of species that were previously placed in conflicting positions by nuclear and chloroplast data, such as C. cupreatus, C. poecilanthus, and C. setiger, are further resolved by adding the nuclear EMB2765 and mitochondrial rps3 genes to the molecular sampling. Analyses of rps3 reveal an accelerated rate of evolution within Croton subg. Geiseleria, the only one of the four subgenera that contains numerous herbaceous, annual species. We provide morphological descriptions, species lists, and a key to the 31 sections and 10 subsections recognized in the New World. New taxa that we describe include C. sects. Alabamenses, Argyranthemi, Cordiifolii, Corinthii, Cupreati, Luetzelburgiorum, Nubigeni, Olivacei, Pachypodi, Prisci, and C. subsects. Cubenses, Jamaicenses, and Sellowiorum. Additional transfers are made to the ranks of subgenus, section, and subsection. A total of 712 species of Croton are currently recognized for the New World, with 702 of them assigned here to section.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146834/1/tax603013.pd

Phylogeny and biogeography of Croton alabamensis (Euphorbiaceae), a rare shrub from Texas and Alabama, using DNA sequence and AFLP data

Croton alabamensis (Euphorbiaceae s.s. ) is a rare plant species known from several populations in Texas and Alabama that have been assigned to var. texensis and var. alabamensis , respectively. We performed maximum parsimony, maximum likelihood, and Bayesian analyses of DNA sequences from the nuclear ribosomal internal transcribed spacer (ITS) and 5.8S regions and chloroplast trn L- trn F regions from collections of the two varieties of C. alabamensis and from outgroup taxa. C. alabamensis emerges alone on a long branch that is sister to Croton section Corylocroton and the Cuban endemic genus Moacroton . Molecular clock analysis estimates the split of C. alabamensis from its closest relatives in sect. Corylocroton at 41 million years ago, whereas the split of the two varieties of C. alabamensis occurred sometime in the Quaternary. Amplified fragment length polymorphism (AFLP) analyses were performed using two selective primer pairs on a larger sampling of accessions (22 from Texas, 17 from Alabama) to further discriminate phylogenetic structure and quantify genetic diversity. Using both neighbour joining and minimum evolution, the populations from the Cahaba and Black Warrior watersheds in Alabama form two well-separated groups, and in Texas, geographically distinct populations are recovered from Fort Hood, Balcones Canyonlands, and Pace Bend Park. Most of the molecular variance is accounted for by variance within populations. Approximately equal variance is found among populations within states and between states (varieties). Genetic distance between the Texas populations is significantly less than genetic distance between the Alabama populations. Both sequence and AFLP data support the same relationships between the varieties of C. alabamensis and their outgroup, while the AFLP data provide better resolution among the different geographical regions where C. alabamensis occurs. The conservation implications of these findings are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72311/1/j.1365-294X.2006.02970.x.pd

Sectional rearrangement of arborescent clades of Croton (Euphorbiaceae) in South America: Evolution of arillate seeds and a new species, Croton domatifer

Most of the arborescent Croton species in the New World were treated by Webster as belonging either to C. sect. Cyclostigma Griseb. or C. sect. Luntia (Neck. ex Raf.) G.L. Webster. The circumscription of C. sect. Cyclostigma has been treated recently. In this paper we focus on C. sect. Luntia, which was subdivided by Webster into two subsections, C. subsect. Matourenses and subsect. Cuneati. Using chloroplast trnL‐F and nuclear ITS DNA sequence data, morphology and a broader sampling of additional Croton lineages, we found that the two subsections are not closely related and form distinct monophyletic groups. Substantial morphological differences support the molecular data. A taxonomic recircumscription of the two subsections, elevated to sectional level, is proposed. A key and taxonomic revision, with new synonyms, is provided for C. sect. Cuneati; together with the description of a new species from the coastal mountains of Venezuela, Croton domatifer. The new species is the only one in the genus known to possess leaf domatia. We infer that species in the Cuneati clade have lost the typical Croton caruncle, and some of them have evolved a different, specialized type of aril. We hypothesize that the arillate seeds are an adaptation to dispersal by fish in the Orinoco and Amazon river basins.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147226/1/tax594014.pd

Croton laceratoglandulosus (Euphorbiaceae s.s. ), a new glandular-stipulate species from Brazil and Bolivia, and its systematic position based on molecular analysis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72371/1/j.1095-8339.2008.00844.x.pd

La posición sistemática de Cubanthus y otras especies arbustivas endémicas de Euphorbia (Euphorbiaceae) en Cuba

Cubanthus (Euphorbiaceae) has traditionally been recognized as a small genus of three similar species restricted to Cuba and Hispaniola. In this study we used DNA sequence data from the nuclear ITS and chloroplast ndhF gene regions to investigate its systematic position and the position of four other shrubby Euphorbia species endemic to Cuba: E. cubensis, E. helenae, E. munizii, and E. podocarpifolia. The results demonstrate that all of these taxa belong to a well-supported Antillean clade nested within Euphorbia that also includes E. punicea and E. gymnonota. For that reason, we treat Cubanthus as a section of Euphorbia instead of a separate genus. Euphorbia sect. Adenorima is relegated to a synonym of sect. Cubanthus. New names are proposed for Cubanthus brittonii and Cubanthus linearifolius (Euphorbia millspaughii and E. scutiformis, respectively), and a new combination is made for Cubanthus umbelliformis (Euphorbia umbelliformis). Section Cubanthus belongs to clade C of Euphorbia and is part of a New World assemblage that includes members of sections Euphorbiastrum, Pteroneurae, Portulacastrum, Stachydium, and the former genus Pedilanthus. Based on both the molecular results and morphological differences, two subsections are proposed: subsect. Cubanthus and subsect. Moa. The molecular phylogeny supports the hypothesis that section Cubanthus radiated entirely within the Antilles and the nearby Bahamian archipelago.Cubanthus (Euphorbiaceae) ha sido tradicionalmente reconocido como un género de tres especies muy similares entre sí y endémicas de las islas de Cuba y La Española. En este estudio se emplearon datos de secuencias de ADN tanto nuclear (ITS) como del cloroplasto (ndhF) para investigar la posición sistemática de Cubanthus y de cuatro especies arbustivas de Euphorbia endémicas de Cuba: E. cubensis, E. helenae, E. munizii, y E. podocarpifolia. Los resultados muestran que todas las especies analizadas pertenecen a un clado Antillano anidado en Euphorbia, al cual también pertenecen E. punicea y E. gymnonota. Por tal razón, tratamos a Cubanthus como una sección de Euphorbia en lugar de un género distinto. Euphorbia sección Adenorima se relega como sinónimo de la sección Cubanthus. Se proponen nuevos nombres para Cubanthus brittonii y C. linearifolius (Euphorbia millspaughii y E. scutiformis, respectivamente) y una nueva combinación para Cubanthus umbelliformis (Euphorbia umbelliformis). La sección Cubanthus pertenece al clado C de Euphorbia y es parte de un grupo del Nuevo Mundo que incluye miembros de las secciones Euphorbiastrum, Pteroneurae, Portulacastrum, Stachydium y del anteriormente reconocido género Pedilanthus. Basado en los resultados moleculares y las diferencias morfológicas, se proponen dos subsecciones: subsección Cubanthus y subsección Moa. La filogenia molecular sustenta la hipótesis de que la sección Cubanthus surgió y se diversificó en Las Antillas y el Archipiélago de Las Bahamas

Quantum Simulation of Tunneling in Small Systems

A number of quantum algorithms have been performed on small quantum computers; these include Shor's prime factorization algorithm, error correction, Grover's search algorithm and a number of analog and digital quantum simulations. Because of the number of gates and qubits necessary, however, digital quantum particle simulations remain untested. A contributing factor to the system size required is the number of ancillary qubits needed to implement matrix exponentials of the potential operator. Here, we show that a set of tunneling problems may be investigated with no ancillary qubits and a cost of one single-qubit operator per time step for the potential evolution. We show that physically interesting simulations of tunneling using 2 qubits (i.e. on 4 lattice point grids) may be performed with 40 single and two-qubit gates. Approximately 70 to 140 gates are needed to see interesting tunneling dynamics in three-qubit (8 lattice point) simulations.Comment: 4 pages, 2 figure

Effect of mastication on lipid bioaccessibility of almonds in a randomized human study and its implications for digestion kinetics, metabolizable energy, and postprandial lipemia

Background: The particle size and structure of masticated almonds impact significantly on nutrient release (bioaccessibility) and digestion kinetics. Objectives: To quantify the effects of mastication on the bioaccessibility of intracellular lipid of almond tissue and examine microstructural characteristics of masticated almonds. Design: In a randomized, subject-blind, crossover trial, 17 healthy subjects chewed natural (NA) or roasted almonds (RA) on 4 separate mastication sessions. Particle size distributions (PSDs) of the expectorated boluses were measured using mechanical sieving and laser diffraction (primary outcome). The microstructure of masticated almonds, including the structural integrity of the cell walls (i.e. dietary fiber), was examined using microscopy. Lipid bioaccessibility was predicted using a theoretical model, based on almond particle size and cell dimensions, and then compared to empirically-derived release data. Results: Inter-subject variations (n=15, 2 subjects withdrew) in PSDs of both NA and RA samples were small (e.g. laser diffraction, CV = 12% and 9%, respectively). Significant differences in PSDs were found between these two almond forms (P 500 µm) in masticated almonds. Microstructural examination of the almonds indicated that most intracellular lipid remained undisturbed in intact cells post-mastication. No adverse events were recorded. Conclusions: Following mastication, most of the almond cells remained intact with lipid encapsulated by cell walls. Thus, most of the lipid (>88%) in masticated almonds is not immediately bioaccessible and remains unavailable for digestion and absorption. The lipid encapsulation mechanism provides a convincing explanation for why almonds have a low metabolizable energy content and an attenuated impact on postprandial lipemia. Trial registration number; ISRCTN58438021

Manipulation of starch bioaccessibility in wheat endosperm to regulate starch digestion, postprandial glycemia, insulinemia, and gut hormone responses: a randomized controlled trial in healthy ileostomy participants

Background: Cereal crops, particularly wheat, are a major dietary source of starch, and the bioaccessibility of starch has implications for postprandial glycemia. The structure and properties of plant foods have been identified as critical factors in influencing nutrient bioaccessibility; however, the physical and biochemical disassembly of cereal food during digestion has not been widely studied. Objectives: The aims of this study were to compare the effects of 2 porridge meals prepared from wheat endosperm with different degrees of starch bioaccessibility on postprandial metabolism (e.g., glycemia) and to gain insight into the structural and biochemical breakdown of the test meals during gastroileal transit. Design: A randomized crossover trial in 9 healthy ileostomy participants was designed to compare the effects of 55 g starch, provided as coarse (2-mm particles) or smooth (0.2-mm particles) wheat porridge, on postprandial changes in blood glucose, insulin, C-peptide, lipids, and gut hormones and on the resistant starch (RS) content of ileal effluent. Undigested food in the ileal output was examined microscopically to identify cell walls and encapsulated starch. Results: Blood glucose, insulin, C-peptide, and glucose-dependent insulinotropic polypeptide concentrations were significantly lower (i.e., 33%, 43%, 40%, and 50% lower 120-min incremental AUC, respectively) after consumption of the coarse porridge than after the smooth porridge (P , 0.01). In vitro, starch digestion was slower in the coarse porridge than in the smooth porridge (33% less starch digested at 90 min, P , 0.05, paired t test). In vivo, the structural integrity of coarse particles (~2 mm) of wheat endosperm was retained during gastroileal transit. Microscopic examination revealed a progressive loss of starch from the periphery toward the particle core. The structure of the test meal had no effect on the amount or pattern of RS output. Conclusion: The structural integrity of wheat endosperm is largely retained during gastroileal digestion and has a primary role in influencing the rate of starch amylolysis and, consequently, postprandial metabolism. This trial was registered at isrctn.org as ISRCTN40517475