bluuebunny/crossref_metadata_2025 huggingface dataset:
Fossil flowers and fruits of the Actinidiaceae from the Campanian (Late Cretaceous) of Georgia
Authors: Keller Jennifer A. , Herendeen Patrick S. , Crane Peter R.
Published: January 2018

A new genus and species of Actinidiaceae (Parasaurauia allonensis gen. et sp. nov.) are established for fossil flowers and fruits from the early Campanian (Late Cretaceous) Buffalo Creek Member of the Gaillard Formation in central Georgia, USA. The fossil flowers, which are exquisitely preserved as charcoal, have five imbricate, quincuncially arranged sepals and petals. The androecium consists of ten stamens with anthers that are deeply sagittate proximally. The gynoecium is tricarpellate, syncarpous, and has three free styles that emerge from an apical depression in the ovary. The fruit is trilocular and contains numerous ovules on intruded axile placentae. The structure of mature fruits is unknown. Comparisons with extant taxa clearly demonstrate that the affinities of Parasaurauia allonensis are with the Ericales, and particularly with the Actinidiaceae, which have been placed among the Ericales in recent cladistic analyses. Because Parasaurauia allonensis is not identical to any one genus of Actinidiaceae, or other member of the Ericales, phylogenetic relationships of the fossil were evaluated through a cladistic analysis using morphological and anatomical characters. Results of this analysis place Parasaurauia allonensis within the Actinidiaceae as sister to the extant genera Saurauia and Actinidia. Parasaurauia allonensis differs from extant Saurauia only in having ten rather than numerous stamens.
Consequences of the timing of seed release of Erythronium americanum (Liliaceae), a deciduous forest myrmecochore
Authors: Ruhren Scott , Dudash Michele R.
Published: January 2018

Myrmecochores are plants with seeds adapted for ant dispersal. This specialized dispersal syndrome may provide Erythronium americanum seeds with protection from predators within the eastern deciduous forests. To determine the adaptive significance of myrmecochory in E. americanum, seed removal rates and seed predation in relation to seed release date and location along the Potomac River in Langley, Virginia, were examined. The number of seeds removed from four exclosure treatments were monitored two times in 1992 and three times in 1993 within floodplain and hilltop populations of E. americanum. Overall, seed removal was greatest from control depots, and E. americanum seeds were removed at nearly the same rate from predator‐exclusion depots, indicating that removal from open depots is largely due to ant removal. Ants removed significantly more seeds than predators in the first 48 h of seed exposure and could potentially remove all E. americanum seeds before nightfall. Aphaenogaster rudis was identified as the primary disperser of E. americanum. Seeds placed in depots after the natural seed release period were discovered more quickly and removed by ants at a significantly higher rate than seeds released at the natural date. These results suggest that ant dispersal of E. americanum seeds reduces the likelihood of seed predation.
Morphological plasticity following species‐specific recognition and competition in two perennial grasses
Authors: Huber‐Sannwald Elisabeth , Pyke David A. , Caldwell Martyn M.
Published: January 2018

Morphological characteristics and biomass allocation of two perennial grasses,Pseudoroegneria spicata(Pursh) A. Löve ssp.spicata(bluebunch wheatgrass) andAgropyron desertorum(Fisch. ex Link) Schult. (crested wheatgrass), were compared under different competition and nutrient treatments. The competitive responses of two plants grown in containers under field conditions were assessed in monocultures and mixtures in two experiments using different scales of nutrient application. In the Small‐Scale Experiment, a localized fertilization was applied in the rooting zone between two plants; in the Large‐Scale Experiment the entire container was supplied with nutrients.Agropyronresponded more vigorously to fertilization than didPseudoroegneria, but based on the relative performance ofAgropyronin monoculture and mixture, it was not superior toPseudoroegneriain resource competition.Pseudoroegneriawas apparently able to recognize neighboring plants as either conspecifics or individuals of the other species. The responses included changes in shoot architecture, root morphology, and allocation between roots and shoots.Agropyrongenerally did not exhibit such morphological flexibility. In field plot plantings of 4‐yr‐old tussocks similar shoot differences were seen inPseudoroegneria.There was, however, no indication of superior resource competition forAgropyron.Thus, any early advantage ofAgropyronin vigorous growth of young plants in response to nutrients was apparently lost by the time the plants had reached this stage of development. Morphological and allocation flexibility ofPseudoroegneriamay have compensated for slower, less vigorous growth. If species‐specific recognition and morphological plasticity are common in nature, this complicates our attempts to understand mechanisms of competition.
The use of Random Amplified Polymorphic DNA (RAPD) markers for the study of taxonomical relationships among species of ASPHODELUS sect. Verinea (Asphodelaceae)
Authors: Lifante Zoila Díaz , Aguinagalde Itzi'ar
Published: January 2018

RAPD analysis was applied to the three species of Asphodelus sect. Verinea (Pomel) Boissier (Asphodelaceae): Asphodelus fistulosus L., A. ayardii Jahand. & Maire, and A. tenuifolius Cav. Fifteen populations, five per species, were used and eight primers were sampled. A total of 97 amplification products were generated, and 4–12 polymorphic products per primer were obtained. Several specific RAPD markers were detected for A. ayardii and A. tenuifolius, while only two for A. fistulosus, which shares most amplification products with the two former species. Results that reinforce the specific status of the three taxa are shown. Asphodelus tenuifolius showed the highest interpopulation variability in agreement with the high specialization of other characters in this species. In accordance with these results, an amphidiploid origin for A. fistulosus, with the participation of A. ayardii and A. tenuifolius, is suggested.
Effects of light, moisture, temperature, and litter on the regeneration of five tree species in the tropical montane wet forest of Puerto Rico
Authors: III Edwin M. Everham , Myster Randall W. , VanDeGenachte Eric
Published: January 2018

Field experiments were conducted to investigate the effects of light, moisture, temperature, and litter on the regeneration of two early‐, one mid‐, and two late‐successional tropical tree species. High light and litter seem to be universally good cues for regeneration, increasing seed/seedling survival for all species except for Cecropia (an early‐successional species) whose small seeds may not be able to penetrate the litter layer. In addition, the high temperature environment in both artificially shaded and nonshaded areas of a natural gap exhibits less seed loss, an increase in the percent and rate of germination, and an increase in seedling survival for Dacryodes (a late‐successional species), than the lower temperature environment under an intact canopy. Low soil water is also a good cue for Dacryodes germination as it is for Prestoea and Cecropia. Finally, the lower temperature environment found under the forest canopy (compared to the natural gap) leads to less seed loss and more germination for Guarea (a mid‐successional species). Our results suggest that a good patch for regeneration of many species in this forest, early‐ as well as late‐successional species, would have high light and a litter layer that moderates temperature and moisture extremes. The substantial variation in suitability among regeneration filters and species could: (1) contribute to low establishment success, i.e., most dispersed propagules do not become trees, (2) make it difficult to group species into germination strategies, and (3) make it hard to generalize about a net effect of any specific environmental variable on establishment. We suggest that tropical disturbances should be viewed in terms of their impact on a variety of environmental cues, which may signal germination and impact subsequent growth and survival.
Patterns of morphological variation, diversity, and domestication of wild and cultivated populations of agave in Yucatan, Mexico
Authors: Colunga‐GarcíaMarín Patricia , Estrada‐Loera Enrique , May‐Pat Filogonio
Published: January 2018

This work presents a statistical and numerical analysis of the patterns of morphological variation of the cultivated variants of henequén (Agave fourcroydes Lem.) presently found in the Mexican state of Yucatan and of the wild populations of A. angustifolia Haw., its putative progenitor. This is the first step in the study of the intrageneric genetic diversity and evolutionary relationships. The study indicated that: (1) There exists a significant discontinuation in morphological variation corresponding to the cultivated variants of traditionally recognized henequén: Sac Ki, Yaax Ki, and Kitam Ki, and to three possible ecotypes of A. angustifolia Haw.: Coastal Dunes, Tropical Deciduous Forest, and Tropical Subdeciduous Forest. (2) Sac Ki and Yaax Ki differ from wild populations in four syndromes of domestication: gigantism, greater fibrosity, less thorniness, and less reproductive capacity. The lower coefficient of variation of their characteristics compared with the wild populations suggests less genetic diversity. This fact, and the disappearance of four out of the seven variants existing early in this century, indicate a dramatic genetic erosion of this crop. (3) Kitam Ki is the cultivated variant more similar to wild ones. Differences with them suggest recent introduction and an artificial selection process with different direction and intensity than the other cultivated variants. (4) A tendency from more to less is observed for characteristics indicating degree of domestication: Sac Ki, Yaax Ki, and Kitam Ki. (5) The differences among the possible wild ecotypes may be associated with the soil conditions and precipitation.
The origins of the genomes of Triticum biunciale, t. ovatum, t. neglectum, t. columnare, and t. rectum (poaceae) based on variation in repeated nucleotide sequences
Authors: Resta Paolo , Zhang g‐Bing , Dubcovsky Jorge , Dvořák Jan
Published: January 2018

The origins of the genomes of allotetraploid species Triticum biunciale, T. ovatum, T. neglectum, and T. columnare, and allohexaploid T. rectum were investigated by examining the presence of specific restriction fragments of repeated nucleotide sequences in DNAs of the polyploid species. The restriction fragments were detectable either in a single diploid Triticum species (unique characters) or a group of diploid species (unique shared characters). The analysis showed that Triticum biunciale and T. ovatum are closely related. In both species, one pair of genomes is closely related to the genome of T. umbellulatum and the other is a modified genome of T. comosum. The same genome formula, UUM°M°, is proposed for T. biunciale and T. ovatum. Potential reasons for the modification of the M° genome are discussed. Triticum neglectum and T. columnare are also closely related to each other and have the same genomes. They share the U genome with T. biunciale and T. ovatum, but their second pair of genomes is unrelated to the M° genome. No relationship was found of this genome to a genome of any extant diploid species of Triticum or any phylogenetic lineage leading to the extant diploid species. This unknown genome is designated X'.∗∗∗ The proposed genome formula for T. neglectum and T. columnare is UUX'X'∗∗∗. Hexaploid T. rectum originated from hybridization of one of the tetraploid species with the formula UUX'X', likely T. neglectum, with T. uniaristatum (genome N), and its genome formula is UUX'X'NN.
Establishment growth of cabbage palm, sabal palmetto (arecaceae)
Authors: McPherson Kelly , Williams Kimberlyn
Published: January 2018

Cabbage palms (Sabal palmetto) go through an establishment phase during which the stem grows downward for a period of time before growing upward. We estimated the duration of this phase for cabbage palms growing in coastal forest in Florida using a matrix model approach. All data were collected over a 2‐yr period (1993‐1995) in coastal forest at Waccasassa∗∗∗ Bay, Florida. The minimum time projected by the model for a plant to develop an aboveground trunk was 14 yr. We estimate that the fastest growing 1, 10, and 50% of plants would develop an aboveground trunk in 33, 42, and 59 yr, respectively. The projected duration of the trunkless phase is surprisingly long but not unlike other palms with similar types of establishment growth. Our estimates are much longer than anecdotal estimates for cabbage palms grown under nursery conditions but are similar to anecdotal estimates for plants grown in field conditions. Management practices that remove cabbage palms with aboveground stems usually leave a population of palms without aboveground stems that serves as temporary reserve for relatively rapid recovery of the palm stand. This may foster the perception by many that cabbage palms are fast growing.
Genetic and maternal effects on offspring fitness inLupinus texensis(Fabaceae)
Authors: Helenurm Kaius , Schaal Barbara A.
Published: January 2018

Two experiments were designed to examine jointly the roles of maternal effect, genetic load, and other genetic variability at nuclear loci in determining offspring fitness inLupinus texensis, an outbreeding annual herb. A diallel crossing design was used to generate seeds in the greenhouse. This design directly compares maternal and paternal contribution to offspring survival, growth, and flowering, and also assesses the role of genetic load because selfs are included in the crossing design. A nested crossing design was used to generate seeds at a field site. This design addresses the contribution of parental plants to their offspring under natural conditions. Maternal effects occur throughout the life cycle, but dominate the early growth of offspring inL. texensis.Inbreeding depression also occurs throughout the life cycle, but primarily affects size and survival of offspring. Overall inbreeding depression is substantial (δ = 0.66), exceeding the twofold threshold required for maintenance of an outcrossing mating system. However, lineages vary in the stages at which inbreeding depression occurs. Moreover, extreme heterogeneity was observed among lineages, with inbreeding depression ranging from negligible (δ = 0.02) to complete (δ = 1.00). This heterogeneity could allow the invasion and maintenance of selfing genotypes in natural populations ofL. texensis.
Concordance and discordance: a tale of two hybrid zones in the pacific coast irises (Iridaceae)
Authors: Young Nelson D.
Published: January 2018

Chloroplast DNA (cpDNA) markers were developed that provided markers unique to a species or that delimited a large area within a species. These markers were then followed across two hybrid zones: Iris douglasiana/Iris∗∗∗ innominata, and Iris chrysophylla/Iris tenax. In each case the cline in haplotype frequency was compared to the cline for a morphologically based hybrid index. In all three transects across the I. douglasianall. innominata hybrid zone, the cpDNA cline was displaced 1‐2 km relative to the morphologically defined hybrid zone; the displacement was not found in the other hybrid zone. The observed displacement represents introgression of cpDNA from ∗∗∗I. douglasiana into ∗∗∗I. innominata. It may be that the I. douglasiana/I.∗∗∗ innominata hybrid zone has shifted in recent time, leaving the slowly dispersing chloroplast DNA behind. The populations known as Iris thompsonii do not form a phylogenetic species and are best viewed as products of hybridization between ∗∗∗I. douglasiana and ∗∗∗I. innominata.
Identification and localization of vegetative STORAGE PROTEINS IN LEGUME LEAVES
Authors: Klauer Stephen F. , Franceschi Vincent R. , Ku Maurice S. B. , Zhang Dianzhong
Published: January 2018

Leaves from 12 legume species representing two subtribes were examined by various techniques for the presence of vegetative storage proteins (VSPs) similar to the 27, 29, and 94 kD VSPs of soybean. Polyacrylamide gel electrophoresis (PAGE) of leaf protein followed by western immunoblotting using antibody that recognizes soybean VSP94, a lipoxygenase, demonstrated that this protein is present in six of the nine species tested. Blotting with antibody to soybean VSP27/29, which are glycoproteins, gave labelling in seven species and glycoprotein affino‐blots showed that glycosylated proteins ranging around 27 to 29 kD were present in all nine species examined. Immunocytochemical localization studies of eight species demonstrated that proteins antigenically similar to VSP94 and VSP27/29 are specifically accumulated in the vacuole of paraveinal mesophyll (PVM) cells. They were not detectable at significant levels in other mesophyll cells using this technique. Comparisons of protein compositions of isolated PVM and mesophyll protoplasts from seven species further confirmed the specialized nature of the PVM. VSP94 and proteins ranging from 25 to 35 kD molecular mass were the major proteins of PVM of all but one species while Rubisco was quite low in amount compared to mesophyll protoplasts. The results show that VSP synthesis and accumulation is a general feature of legume leaves containing a PVM layer and indicate that the PVM plays a specialized role in nitrogen metabolism and partitioning in these species.
The phylogenetic relationships of the physaloid genera (Solanaceae) based on morphological data
Authors: Axelius Barbro
Published: January 2018

A group of genera, e.g., Chamaesaracha, Leucophysalis, Physaliastrum, Margaranthus, and Withania, in the subfamily Solanoideae (Solanaceae) is centered around the genus Physalis and has been named the physaloid group. It comprises a number of small and often poorly known genera, sometimes seen as united with Physalis and/or each other. A hypothesis of the phylogenetic relationships within this group, based on parsimony analyses of morphological data, is here presented for the first time. The result is discussed in relation to prevailing generic circumsciptions and taxonomic consequences. It is also compared with hypotheses of relationships based on cpDNA data.
Sun‐shade adaptability of the red mangrove, Rhizophora mangle (Rhizophoraceae): Changes through ontogeny at several levels of biological organization
Authors: Farnsworth Elizabeth J. , Ellison Aaron M.
Published: January 2018

Rhizophora mangle L., the predominant neotropical mangrove species, occupies a gradient from low intertidal swamp margins with high insolation, to shaded sites at highest high water. Across a light gradient, R. mangle shows properties of both “light‐demanding” and “shade‐tolerant” species, and defies designation according to existing successional paradigms for rain forest trees. The mode and magnitude of its adaptability to light also change through ontogeny as it grows into the canopy. We characterized and compared phenotypic flexibility of R. mangle seedlings, saplings, and tree modules across changing light environments, from the level of leaf anatomy and photosynthesis, through stem and whole‐plant architecture. We also examined growth and mortality differences among sun and shade populations of seedlings over 3 yr. Sun and shade seedling populations diverged in terms of four of six leaf anatomy traits (relative thickness of tissue layers and stomatal density), as well as leaf size and shape, specific leaf area (SLA), leaf internode distances, disparity in blade–petiole angles, canopy spread: height ratios, standing leaf numbers, summer (July) photosynthetic light curve shapes, and growth rates. Saplings showed significant sun/shade differences in fewer characters: leaf thickness, SLA, leaf overlap, disparity in bladepetiole angles, standing leaf numbers, stem volume and branching angle (first‐order branches only), and summer photosynthesis. In trees, leaf anatomy was insensitive to light environment, but leaf length, width, and SLA, disparities in bladepetiole angles, and summer maximal photosynthetic rates varied among sun and shade leaf populations. Seedling and sapling photosynthetic rates were significantly depressed in winter (December), while photosynthetic rates in tree leaves did not differ in winter and summer. Seasonal and ontogenetic changes in response to light environment are apparent at several levels of biological organization in R. mangle, within constraints of its architectural baiiplan. Such variation has implications for models of stand carbon gain, and suggest that response flexibility may change with plant age.
Phylogeny of subfamily Epidendroideae (Orchidaceae) inferred from ndhF chloroplast gene sequences
Authors: Neyland Ray , Urbatsch Lowell E.
Published: January 2018

This project undertakes the first molecular‐based phylogenetic study of subfamily Epidendroideae (Orchidaceae). Approximately 1200 nucleotides (from the 3' half of the chloroplast gene ndhF for 34 orchid taxa and a lilioid monocot, Clivia miniata (Amaryllidaceae), were subjected to phylogenetic analysis using parsimony and maximum likelihood methods. Oryza sativa (Poaceae), a nonlilioid monocot, was designated as outgroup. Trees from both parsimony and maximum likelihood methods suggest that subfamily Epidendroideae is monophyletic, with Listera (Neottieae) as sister. Although subtribal relationships are typically well resolved and have strong branch support, intertribal relationships are generally poorly resolved. Perhaps this general lack of resolution among tribes reflects a rapid species radiation that coincided with anatomical, physiological, and anatomical adaptations that initiated large‐scale epiphytism in the ancestral Epidendroideae. Six taxa in this study exhibit deletions that are not evenly divisible by three and result in extensive sequence frameshifts. For example, one deletion is 227 bp in length and is flanked by the short direct repeat sequence; TCAATAGGAATTTCTTTT. Multiple deletions and frameshifts suggest that ndhF may be a pseudogene, in at least some orchid taxa.
Monophyly and generic relationships of polemoniaceae based on matK Sequences
Authors: Johnson Leigh A. , Schultz Joanna L. , Soltis Douglas E. , Soltis Pamela S.
Published: January 2018

Polemoniaceae are often considered a model family for studying evolutionary processes, yet a reliable phylogeny for the family is only now beginning to emerge. To test the monophyly of this family and to elucidate intergeneric relationships, we employed comparative sequencing of the chloroplast gene matK. Parsimony analysis of matK sequences representing 18 genera of Polemoniaceae and nine families from Asteridae sensu lato places Polemoniaceae apart from Solanaceae near Fouquieriaceae, Ericaceae, Sarraceniaceae, and Diapensiaceae. Both this and a subsequent analysis of 59 species of Polemoniaceae indicate that Cobaea is derived from within Polemoniaceae, rather than being the sister to Polemoniaceae as suggested by some authors. The tropical genera Bonplandia, Cantua, and Cobaea form a clade, and the remaining, primarily temperate genera, excluding Acanthogilia, form a second monophyletic group. Acanthogilia is placed ambiguously as sister to either the tropical or temperate groups depending on the location of the root for Polemoniaceae. Within the temperate lineage, Polemonium is sister to three large clades: a well‐supported clade comprising Phlox, Gymnosteris, Linanthus, Leptodactylon, and Gilia filiformis; a moderately well‐supported clade comprising Allophyllum, Collomia, Navarretia, and several species of Gilia; and a weakly supported clade comprising Eriastrum, Ipomopsis, Langloisia, Loeseliastrum, Loeselia, and several species of Gilia. In addition to revealing the extreme polyphyly of Gilia, this analysis suggests that Ipomopsis and Linanthus are also polyphyletic.
RFLP AND CYTOGENETIC EVIDENCE ON THE ORIGIN AND EVOLUTION OF ALLOTETRAPLOID DOMESTICATED peanut,Arachis hypogaea(Leguminosae)
Authors: Kochert Gary , Stalker H. Thomas , Gimenes Marcos , Galgaro Leticia , Lopes Catalina Romero , Moore Kim
Published: January 2018

Nuclear restriction fragment length polymorphism (RFLP) analysis was used to determine the wild diploidArachisspecies that hybridized to form tetraploid domesticated peanut. Results using 20 previously mapped cDNA clones strongly indicatedA. duranensisas the progenitor of the A genome of domesticated peanut andA. ipaensisas the B genome parent. A large amount of RFLP variability was found among the various accessions ofA. duranensis, and accessions most similar to the A genome of cultivated peanut were identified. Chloroplast DNA RFLP analysis determined thatA. duranensiswas the female parent of the original hybridization event. Domesticated peanut is known to have one genome with a distinctly smaller pair of chromosomes (“A”), and one genome that lacks this pair. Cytogenetic analysis demonstrated thatA. duranensishas a pair of “A” chromosomes, andA. ipaensisdoes not. The cytogenetic evidence is thus consistent with the RFLP evidence concerning the identity of the progenitors. RFLP and cytogenetic evidence indicate a single origin for domesticated peanut in Northern Argentina or Southern Bolivia, followed by diversification under the influence of cultivation.
Chemotaxonomy of the Hymenophyllaceae. II. C‐GLYCOSYLFLAVONES AND FLAVONE‐O‐GLYCOSIDES OF TRICHOMANES S.L.
Authors: Wallace James W.
Published: January 2018

An analysis of 23 species of Trichomanes s. 1. indicates that the presence of C‐glycosylflavones, especially mono‐C‐glycosylflavones, may be a basic characteristic for this genus. Except for the morphologically unique Cardiomanes reniforme, this feature appears to delimit the species of Trichomanes s. 1. from those of Hymenophyllum s. 1. Several species, primarily those classified within Didymoglossum (according to both Copeland and Morton), synthesize flavone‐O‐glycosides in addition to their C‐glycosylflavone profiles. Two species, T. birmanicum and T. radicans, appear to be unique in synthesizing the di‐C‐glycosylflavones violanthin and isoviolanthin; five species (T. collariatum, T. scandins, T. birmanicum, T. bicorne, and T. alatum) appear to synthesize di‐C‐glycosylflavones but lack mono‐C‐glycosylflavones. Based on this and other studies, it may be appropriate to consider these C‐glycosylflavone‐producing plants as representing primitive leptosporangiate stock.
Effect of oxygen availability and salinity on early life history stages of salt marsh plants. II. Early seedling development advantage of Spartina alterniflora over Phragmites australis (Poaceae)
Authors: Wijte Antonia H. B. M. , Gallagher John L.
Published: January 2018

In salt marsh soils, germination and the first phases of seedling development often occur under dark, hypoxic or anoxic, and saline conditions. Spartina alterniflora and Phragmites australis seedling development were examined under covaried oxygen and salinity concentrations in growth chamber experiments. First, the effects of oxygen and salinity on seedling development were tested in the dark, using a 5 5 factorial design. Oxygen did not affect P. australis plumule growth at oxygen concentrations from 21 down to 2.5%. Plumules were longer at ≤10 than at ≥25 g NaCl/L. Root growth was maximum in 21% oxygen, at ≤10 g NaCl/L and reduced at all salinities in oxygen concentrations ≤10%. No plumule or root growth occurred under anoxia. Salinity did not affect S. alterniflora mesocotyl emergence, which was fastest in anoxia and hypoxia. Mesocotyls did not emerge from the spikelet in 21% oxygen. In contrast, plumule growth was fastest in 21% oxygen, but was inhibited in anoxia. Under low oxygen and high salinity both plumule and root elongation were reduced. Coleoptile and mesocotyl elongation were greatest in 2.5 and 5% oxygen, and shortest in anoxia. The percentage of mesocotyls elongating was also highest in 2.5% oxygen. Rapid S. alterniflora coleoptile and mesocotyl elongation in anoxia enables its seedlings to escape the impact of the stressful environment where its seeds can germinate, but the seedlings could not survive otherwise. In separate experiments, S. alterniflora seeds were germinated and the seedlings grown in the dark for 10 d, then exposed to light for 4 d. Prior to illumination the seedlings did not develop beyond the stage of a small plumule enclosed in the coleoptile. Within 48 h of illumination in the presence of CO2, roots emerged and the plumule elongated inside the coleoptile at salinities up to 40 g NaCl/L, while the external environment remained anoxic. Without CO2, plumule growth and root development did not occur. This suggested oxygen was produced inside the coleoptile by the photosynthesizing plumule, and triggered root development. The ability of S. alterniflora seedlings to continue development under external anoxia and high salinity gives that species a competitive advantage over P. australis in high salinity and/or poorly drained marshes.
The role of stem recharge in reducing the winter desiccation of Picea engelmannii (Pinaceae) needles at alpine timberline
Authors: Sowell John B. , McNulty Seth P. , Schilling Bradley K.
Published: January 2018

The winter desiccation of needles is thought to limit tree growth and survival within alpine timberline ecotones of the southern Rocky Mountains, USA. To better understand the factors contributing to this desiccation damage, the extent to which stem water was available to needles of Picea engelmannii undergoing desiccation at timberline near Monarch Pass, Colorado, was monitored throughout the winter. Severed shoots experienced significantly greater desiccation than did intact shoots, indicating the availability of stem water to needles despite presumably frozen soil, roots, and stems. A model of water relations during winter predicted more extreme desiccation of severed shoots than observed. This suggests that one or more of the common assumptions concerning the winter water relations of timberline trees is in error. The influence of cold, dry conditions on the cuticular conductance of Picea engelmannii needles is not known and therefore not accounted for in current models of winter water relations. The assumption that cuticular conductance is not influenced by temperature or humidity is a likely source of error in such models.
Origins of the new allopolyploid species Senecio cambrensis (asteraceae) and its relationship to the canary islands endemic Senecio teneriffae
Authors: Lowe Andrew J. , Abbott Richard J.
Published: January 2018

The distribution of a 330 bp cpDNA insertion was reexamined in British material of Senecio cambrensis (2n = 6x = 60), its two putative parental taxa, S. squalidus (2n = 2x = 20) and S. vulgaris (2n = 4x = 40), and the closely related Canary Islands' endemic S. teneriffae (2n = 6x = 60). This formed part of a test of the hypothesis that the Welsh form of S. cambrensis is derived from introduced S. teneriffae rather than having originated in Wales via allopolyploidy as previously supposed. It was established that the 330 bp insertion was carried by all plants of Welsh S. cambrensis and also S. teneriffae, but was absent from the cpDNA of Edinburgh S. cambrensis and all plants of British S. squalidus and S. vulgaris var. vulgaris surveyed. However, two of 19 individuals tested of S. vulgaris var. hibernicus also possessed the cpDNA insertion, indicating that it is present in British material of S. vulgaris, although at low frequency. The close similarity between S. teneriffae and S. cambrensis, especially the Welsh form of S. cambrensis, was confirmed by the results of a restriction analysis of rDNA, and also morphometric and crossing studies. However, isozyme analysis showed that S. teneriffae is monomorphic for βEST‐3 and ACO‐1 phenotypes that are not present in Welsh and Edinburgh S. cambrensis, nor in S. squalidus and S. vulgaris material surveyed. It is concluded that S. teneriffae and S. cambrensis are two closely related allohexaploid taxa that have very similar, but different origins. It is postulated that whereas S. cambrensis (in Wales and Edinburgh) is the allohexaploid of S. vulgaris and S. squalidus, S. teneriffae is possibly the allohexaploid of S. vulgaris and S. glaucus, the latter being a diploid species closely related to S. squalidus.
Karyology and phylogeny of some Mesoamerican species of Zamia (Zamiaceae)
Authors: Caputo Paolo , Cozzolino Salvatore , Gaudio Luciano , Moretti Aldo , Stevenson Dennis W.
Published: January 2018

Chromosome numbers and karyotypes of four species of Zamia L. (Zamiaceae) are described. Plants of Z. manicata from Colombia are 2n = 18 with eight metacentric (M), four submetacentric (S), two acrocentric (A), and four telocentric (T) chromosomes. Plants of Z. ipetiensis from Panama are 2n = 23 with 3M + 4S + 2A + 14T. Plants of Z. cunaria from Panama have two different chromosome numbers, 2n = 23 with 3M + 4S + 2A + 14T and 2n = 24 with 2M + 4S + 2A + 16T. Plants of Z. acuminata from Costa Rica and Panama are 2n = 24 with 2M + 4S + 2A + 16T. On the basis of the occurrence of a one‐to‐two‐ratio in the variation of M‐ and T‐chromosome numbers in the karyotypes, centric fission or fusion are considered for their potential involvement in the chromosome variation of these plants. Data deriving from morphology and karyology, interpreted in a cladistic framework, suggest that centric fission rather than centric fusion is involved in the karyotype diversification of the four species and their closest Mesoamerican allies.
Malnutrition Identified by Academy of Nutrition and Dietetics/American Society for Parenteral and Enteral Nutrition Is Associated With More 30‐Day Readmissions, Greater Hospital Mortality, and Longer Hospital Stays: A Retrospective Analysis of Nutrition Assessment Data in a Major Medical Center
Authors: Hudson Lauren , Chittams Jesse , Griffith Cody , Compher Charlene
Published: January 2018

Background

Few studies have compared malnutrition identified by the Academy of Nutrition and Dietetics/American Society for Parenteral and Enteral Nutrition (AND/ASPEN) consensus criteria with clinical outcomes. Our goal was to compare 30‐day readmissions (primary outcome), hospital mortality, length of stay (LOS) in survivors, and time to discharge alive (TDA) in all patients assessed as malnourished or not malnourished using these criteria in fiscal year 2015. We hypothesized more frequent admissions, greater mortality, longer LOS, and less likely shorter TDA in the malnourished patients.

Methods

Demographic variables, clinical outcomes, and malnutrition diagnosis for all initial patient admissions were obtained retrospectively from the electronic medical record. Logistic regression was used to compare categorical and Cox proportional hazards for TDA in unadjusted and adjusted (age, sex, race, medical/surgical admission, Charlson Comorbidity Index) models.

Results

Of the 3907 patients referred for nutrition assessment, 66.88% met criteria for moderate or severe malnutrition. Malnourished patients were older (61 vs 58 years, P < .0001), and survivors had longer LOS (15 vs 12 days, P = .0067) and were more likely to be readmitted within 30 days (40% vs 23%, P < .0001). In adjusted models, 30‐day readmissions (odds ratio [OR] 2.13, 95% confidence interval [CI] 1.82–2.48) and hospital mortality (OR 1.47, 95% CI 1.0–1.99) were increased, and the likelihood of earlier TDA was reduced (hazard ratio [HR] 0.55, 95% CI 0.44–0.77) in those who had >2‐day stay.

Conclusion

The AND/ASPEN criteria identified malnourished patients in a high‐risk population who had more adverse clinical outcomes. Further studies are needed to determine whether optimal provision of nutrition support can improve these outcomes.
Faecalibacterium prausnitzii and a Prebiotic Protect Intestinal Health in a Mouse Model of Antibiotic and Clostridium difficile Exposure
Authors: Roychowdhury Sanjoy , Cadnum Jennifer , Glueck Bryan , Obrenovich Mark , Donskey Curtis , Cresci Gail A.M.
Published: January 2018

Background

Clostridium difficile (CD) infection (CDI) increases patient morbidity, mortality and healthcare costs. Antibiotic treatment induces gut dysbiosis and is both a major risk factor for CD colonization and treatment of CDI. Probiotics have been trialed to support commensal gut microbiota and reduce CDI. This study investigated commensal microbe Faecalibacterium prausnitzii (FP) and a prebiotic, both known to yield butyrate and be anti‐inflammatory and immunomodulatory, on CD colonization and gut integrity in mice.

Methods

Mice were randomly grouped and supplemented daily with FP, prebiotic, FP + prebiotic, FP/prebiotic supernatant, or saline throughout the entire study. Following treatment with clindamycin for 3 days, mice were exposed to CD. Feces were collected at baseline, the day after antibiotic, and 1, 3, and 5 days after CD exposure and cultured for bacterial overgrowth and CD colonization. On days 1 and 5 after CD exposure, mice were randomly euthanized, and proximal colon was dissected for histological analysis and preparation of RNA for analysis of proinflammatory and anti‐inflammatory cytokines.

Results

Although all mice exhibited bacterial overgrowth and CD colonization, bacterial burden resolved quicker in the FP + prebiotic group. This was associated with induction and resolution of innate immune responses, anion exchanger, and tight junction protein preservation in proximal colon. CD toxin virulence potential was questionable as expression of CD toxin B receptor was depleted in the FP + prebiotic group.

Conclusion

Supplementation with anti‐inflammatory butyrate‐supporting commensal bacteria and prebiotic may support innate immune responses and minimize bacterial burden and negative effects during antibiotic and CD exposure.
Evaluation of Amazon fruits: chemical and nutritional studies onBorojoa sorbilis
Authors: Rabelo Rodrigues Francimilton , de Souza Ramos Aline , Fernandes Amaral Ana Claudia , Pinto Ferreira José Luiz , da Silva Carneiro Carla , Rocha de Andrade Silva Jefferson
Published: January 2018

BACKGROUND

Borojoa sorbilis(Ducke) is an Amazonian species with edible fruits that are widely consumed by the local population, but little studied and not yet economically explored. Thus the aim of this study was to describe the chemical composition, volatile compounds, nutritional aspects and antioxidant activity of the fruit pulp and peel ofB. sorbilis.

RESULTS

Headspace solid‐phase microextraction, using polydimethylsiloxane–divinylbenzene (PDMS‐DVB) fiber, resulted in the identification of 59 substances in the pulp and peel ofB. sorbilisfruits after analysis of the chromatograms obtained by gas chromatography–mass spectrometry using polar and nonpolar columns. Esters were the most abundant. Moisture, lipids, protein, dietary fiber, ash, carbohydrate, total energy value, titratable acid, soluble solids and pH were measured. Protein amount, fat content and antioxidant activity were low in both pulp and peel. Carbohydrate content was 179.2 and 134.9 g kg−1in pulp and peel, respectively.

CONCLUSION

This is the first report on the chemical characteristics, flavor and nutritional aspects ofB. sorbilisfruit, which is essential to its economic exploitation. The high energy value associated with the carbohydrate content, plus the low fat content, contribute to a possible use ofB. sorbilisfruits as a food supplement. © 2018 Society of Chemical Industry
The physical limnology of a permanently ice‐covered and chemically stratified Antarctic lake using high resolution spatial data from an autonomous underwater vehicle
Authors: Spigel Robert H. , Priscu John C. , Obryk Maciej K. , Stone William , Doran Peter T.
Published: January 2018

We used an Environmentally Non‐Disturbing Under‐ice Robotic ANtarctic Explorer to make measurements of conductivity and temperature in Lake Bonney, a chemically stratified, permanently ice‐covered Antarctic lake that abuts Taylor Glacier, an outlet glacier from the Polar Plateau. The lake is divided into two lobes – East Lobe Bonney (ELB) and West Lobe Bonney (WLB), each with unique temperature and salinity profiles. Most of our data were collected in November 2009 from WLB to examine the influence of the Taylor Glacier on the structure of the water column. Temperatures adjacent to the glacier face between 20 m and 22 m were 3°C colder than in the rest of WLB, due to latent heat transfer associated with melting of the submerged glacier face and inflow of cold brines that originate beneath the glacier. Melting of the glacier face into the salinity gradient below the chemocline generates a series of nearly horizontal intrusions into WLB that were previously documented in profiles measured with 3 cm vertical resolution in 1990–1991. WLB and ELB are connected by a narrow channel through which water can be exchanged over a shallow sill that controls the position of the chemocline in WLB. A complex exchange flow appears to exist through the narrows, driven by horizontal density gradients and melting at the glacier face. Superimposed on the exchange is a net west‐to‐east flow generated by the higher volume of meltwater inflows to WLB. Both of these processes can be expected to be enhanced in the future as more meltwater is produced.
Avoiding timescale bias in assessments of coastal wetland vertical change
Authors: Breithaupt Joshua L. , Smoak Joseph M. , Byrne Robert H. , Waters Matthew N. , Moyer Ryan P. , Sanders Christian J.
Published: January 2018

There is concern that accelerating sea‐level rise will exceed the vertical growth capacity of coastal‐wetland substrates in many regions by the end of this century. Vertical vulnerability estimates rely on measurements of accretion and/or surface‐elevation‐change derived from soil cores and/or surface elevation tables (SETs). To date there has not been a broad examination of whether the multiple timescales represented by the processes of accretion and elevation change are equally well‐suited for quantifying the trajectories of wetland vertical change in coming decades and centuries. To examine the potential for timescale bias in assessments of vertical change, we compared rates of accretion and surface elevation change using data derived from a review of the literature. In the first approach, average rates of elevation change were compared with timescale‐averaged accretion rates from six regions around the world where sub‐decadal, decadal, centennial, and millennial timescales were represented. Second, to isolate spatial variability, temporal comparisons were made for regionally unique environmental categories within each region. Last, comparisons were made of records from sites where SET‐MH stations and radiometric measurements were co‐located in close proximity. We find that rates vary significantly as a function of measurement timescale and that the pattern and magnitude of variation between timescales are location‐specific. Failure to identify and account for temporal variability in rates will produce biased assessments of the vertical change capacity of coastal wetlands. Robust vulnerability assessments should combine accretion rates from multiple timescales with the longest available SET record to provide long‐term context for ongoing monitoring observations and projections.
Characterization and Finite Element Analysis of the Tensile Behavior of Electrospun Polymer Single Fibers
Authors: Ma Shuaijiang , Wang Shiwei , Leng Yuting , Li Qian , Hu Guo‐Hua
Published: January 2018

In this paper, polymer single fibers are prepared by electro‐spinning technology with different solvent rations, and the micromechanics properties are investigated together with the finite element analysis. It is found that the tensile stress–strain curves of single fibers can be attributed to two kinds of trends, which are independent of the solvent ratios. A possible arrangement model of polymer chains within the electrospun fibers is proposed according to the tensile stress–strain curves and the mechanics theories. The effect of polymer chains arrangement on the mechanical properties of the fibers is explored by the finite element analysis. This research shows a practical reference to predict the relationship between orientation degree of polymer chains and mechanical properties within the fibers.
Initial evaluation of Advanced Collapsed cone Engine dose calculations in water medium for I‐125 seeds and COMS eye plaques
Authors: Morrison Hali , Menon Geetha , Larocque Matthew P. , van Veelen Bob , Niatsetski Yury , Weis Ezekiel , Sloboda Ron S.
Published: January 2018

Purpose

To investigate the dose calculation accuracy in water medium of the Advanced Collapsed cone Engine (ACE) for three sizes of COMS eye plaques loaded with low‐energy I‐125 seeds.

Methods

A model of the Oncura 6711 I‐125 seed was created for use with ACE in Oncentra® Brachy (OcB) using primary‐scatter separated (PSS) point dose kernel and Task Group (TG) 43 datasets. COMS eye plaque models of diameters 12, 16, and 20 mm were introduced into the OcB applicator library based on 3D CAD drawings of the plaques and Silastic inserts. To perform TG‐186 level 1 commissioning, treatment plans were created in OcB for a single source in water and for each COMS plaque in water for two scenarios: with only one centrally loaded seed, or with all seed positions loaded. ACE dose calculations were performed in high accuracy mode with a 0.5 × 0.5 × 0.5 mm3 calculation grid. The resulting dose data were evaluated against Monte Carlo (MC) calculated doses obtained with MCNP6, using both local and global percent differences.

Results

ACE doses around the source for the single seed in water agreed with MC doses on average within < 5% inside a 6 × 6 × 6 cm3 region, and within < 1.5% inside a 2 × 2 × 2 cm3 region. The PSS data were generated at a higher resolution within 2 cm from the source, resulting in this improved agreement closer to the source due to fewer approximations in the ACE dose calculation. Average differences in both investigated plaque loading patterns in front of the plaques and on the plaque central axes were ≤ 2.5%, though larger differences (up to 12%) were found near the plaque lip.

Conclusions

Overall, good agreement was found between ACE and MC dose calculations for a single I‐125 seed and in front of the COMS plaques in water. More complex scenarios need to be investigated to determine how well ACE handles heterogeneous patient materials.
Utility of the Phenacyl Protecting Group in Traceless Protein Semisynthesis through Ligation–Desulfurization Chemistry
Authors: Matveenko Maria , Hackl Stefanie , Becker Christian F. W.
Published: January 2018

Semisynthesis of proteins via expressed protein ligation is a widely applicable method, even more so because of the possibility of ligation at non‐cysteine sites using β‐mercapto amino acids that can be converted to the corresponding native amino acids by desulfurization. A drawback of this ligation– desulfurization approach is the removal of any unprotected native cysteine residues within the ligated protein segments. Here, we show that the phenacyl (PAc) moiety can be successfully used to protect cysteines within recombinantly generated protein segments. As such, this group was selectively appended onto cysteine side chains within bacterially expressed polypeptides following intein cleavage, which reveals a rather sensitive thioester at the C‐terminus. The PAc group proved to be compatible with native chemical ligation, radical desulfurization, and reverse‐phase HPLC conditions, and was smoothly removed at the end. The utility of the PAc protecting group was then demonstrated by the ‘traceless’ semisynthesis of two proteins containing one or two native cysteines: human small heat shock protein Hsp27 and murine prion protein.