bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurogenesis, Angiogenesis, and MRI Indices of Functional Recovery From Stroke
Authors: Chopp Michael , Zhang Zheng Gang , Jiang Quan
Published: February 2007

This article analyzes the mechanisms underlying the potentiation of functional recovery poststroke by cell-based and pharmacologic agents, which amplify endogenous neurogenesis in the subventricular zone and angiogenesis in the border of the ischemic lesion in the animal. Discussion of the interaction between angiogenesis and neurogenesis is provided and data are described demonstrating a role for matrix metalloproteinases expressed in periinfarct vasculature as chemotactic for neuroblasts migrating from the subventricular zone. Monitoring angiogenesis and structural changes in the ischemic brain associated with functional recovery by means of MRI is described. We demonstrate that injured brain can be stimulated to promote angiogenesis and neurogenesis, which are coupled restorative processes that contribute to functional recovery from stroke and that MRI indices of these neurorestorative events are highly correlative with neurologic function and may be used in real-time monitoring of recovery from stroke.
Preconditioning Reprograms the Response to Ischemic Injury and Primes the Emergence of Unique Endogenous Neuroprotective Phenotypes
Authors: Stenzel-Poore Mary P. , Stevens Susan L. , King Jeffrey S. , Simon Roger P.
Published: February 2007

Ischemic tolerance in the brain, in which sub-threshold insults increase resistance to subsequent injurious ischemia, is a powerful adaptive defense that involves an endogenous program of neuroprotection. Emerging evidence from genomic studies suggests diverse stimuli that trigger preconditioning achieve neuroprotection through a common process which depends on a fundamental reprogramming of the response to injury. Such reprogramming of the genomic response to injury leads to the induction of novel neuroprotective pathways not ordinarily found in the setting of ischemia. Genomic studies also indicate that the nature of the preconditioning stimulus (eg, brief ischemia or endotoxin [lipopolysaccharide]) dictates the phenotype of neuroprotection, a phenotype that parallels protective adaptations also found in certain physiological conditions where the preconditioning stimulus exists at levels that can induce injury. The idea that preconditioning leads to a fundamental reprogramming event that confers neuroprotection is a novel and important concept in the field of ischemic tolerance. Moreover, the view that distinct preconditioning stimuli confer neuroprotection via effectors that differ according to the nature of the preconditioning stimulus offers promise that multiple, nonoverlapping pathways may be discovered as novel neuroprotective therapies.
Effect of High-Dose Atorvastatin on Hospitalizations for Heart Failure
Authors: Khush Kiran K. , Waters David D. , Bittner Vera , Deedwania Prakash C. , Kastelein John J.P. , Lewis Sandra J. , Wenger Nanette K.
Published: February 2007

Background—

Statins reduce the rate of major cardiovascular events in high-risk patients, but their potential benefit as treatment for heart failure (HF) is less clear.

Methods and Results—

Patients (n=10 001) with stable coronary disease were randomized to treatment with atorvastatin 80 or 10 mg/d and followed up for a median of 4.9 years. A history of HF was present in 7.8% of patients. A known ejection fraction <30% and advanced HF were exclusion criteria for the study. A predefined secondary end point of the study was hospitalization for HF. The incidence of hospitalization for HF was 2.4% in the 80-mg arm and 3.3% in the 10-mg arm (hazard ratio, 0.74; 95% confidence interval, 0.59 to 0.94;
P
=0.0116). The treatment effect of the higher dose was more marked in patients with a history of HF: 17.3% versus 10.6% in the 10- and 80-mg arms, respectively (hazard ratio, 0.59; 95% confidence interval, 0.4 to 0.88;
P
=0.009). Among patients without a history of HF, the rates of hospitalization for HF were much lower: 1.8% in the 80-mg group and 2.0% in the 10-mg group (hazard ratio, 0.87; 95% confidence interval, 0.64 to 1.16;
P
=0.34). Only one third of patients hospitalized for HF had evidence of preceding angina or myocardial infarction during the study period. Blood pressure was almost identical during follow-up in the treatment groups.

Conclusions—

Compared with a lower dose, intensive treatment with atorvastatin in patients with stable coronary disease significantly reduces hospitalizations for HF. In a post hoc analysis, this benefit was observed only in patients with a history of HF. The mechanism accounting for this benefit is unlikely to be due primarily to a reduction in interim coronary events or differences in blood pressure.
Identity of Trechmann's ‘β-tin’ with stannous sulphide
Authors: Spencer L. J.
Published: February 2007

In 1879 the late Dr. C. O. Trechmann described in the pages of this Magazine some orthorhombic crystals from Cornish tin furnaces, which from the analyses of the late Mr. J. H. Collins were stated to be metallic tin. Shortly afterwards Baron Foullon described similar crystals from tin furnaces in Bohemia, arriving at the same results, and thus apparently confirming the observations of the previous authors. At a later date, in 1898, Dr. W. P. Headden analysed crystals of similar appearance, also from Cornish tin furnaces, which he found to be stannous sulphide (SnS), hut he stated that these crystals were monoclinic.
On the South African meteorites Mount Ayliff and Simondium, and the chemical composition of the meteorites Adare and Ensisheim (with Plate IV)
Authors: Prior G.T.
Published: February 2007

During the year 1919 specimens of some of the meteorites preserved in the Public Museum of King Willlam's Town, South Africa, were kindly placed by the Curator, the late Yr. F. A. O. Pyre, at the disposal of the writer for investigation. One of these specimens was a meteoric iron labelled Mount Ayliff, another a mass of oxidized material labelled Western Cape Province, and a third a small piece of iron labelled ‘found on Elandsburg at an altitude of 6,000 ft. in 1888’ Unfortunately Mr. Pyre was not in a position to supply very much more information about the specimens.
Tyuyamunite from the Tyuya-Muyun radium mine in Fergana
Authors: Chirvinsky Petr N. , Чирвиский П. Н.
Published: February 2007

Tyuyamunite from Tyuya-Muyun was established as a mineral species by K. A. Nenadkevich in 1912. It is closely allied to carnotite, differing from this in containing calcium in place of potassium, and also, according to W. F. Hillebrand, in the degree of hydration. On this account the mineral has been also known as calciocarnotite.
Ascorbate deficiency results in impaired neutrophil apoptosis and clearance and is associated with up-regulation of hypoxia-inducible factor 1α
Authors: Vissers Margret C M , Wilkie Rachel P
Published: February 2007

Some cells, including neutrophils, accumulate high intracellular ascorbate concentrations, which suggests that they have an important function in these cells. In this study we have used L-gulono-γ-lactone oxidase (Gulo)−/− mice, which are unable to synthesize ascorbate, to generate ascorbate-deficient neutrophils and have used these to investigate the effect of ascorbate on neutrophil function. Peritoneal neutrophils from ascorbate-deficient animals had normal morphology and respiratory burst activity but failed to undergo spontaneous apoptosis, determined by morphology and the surface expression of phosphatidylserine. Initially, there was increased cell survival, but death eventually occurred by necrosis within 48 h. Neutrophils persisted in thioglycollate-induced inflammation in Gulo−/Ȓ mice with the later appearance of necrotic cells, suggesting that apoptosis was also affected in vivo. Also, ascorbate-deficient neutrophils were not recognized by macrophages in an in vitro assay for phagocytosis, providing further evidence for defective apoptosis and clearance. Neutrophils from Gulo−/− mice had elevated levels of hypoxia-inducible factor (HIF)-1α, a transcription factor regulated by Fe2+-dependent hydroxylases which require ascorbate for optimal activity. HIF-1α has been shown previously to inhibit neutrophil apoptosis under hypoxic conditions. Our results suggest that in ascorbate deficiency, up-regulation of HIF-1α blocks neutrophil apoptosis under normoxic conditions and that this represents a novel and important function for vitamin C in inflammatory cells.
Regulatory Cytokine Gene Polymorphisms and Risk of Colorectal Carcinoma
Authors: CRIVELLO ANTONINO , GIACALONE ANTONIO , VAGLICA MARINA , SCOLA LETIZIA , FORTE GIUSI IRMA , MACALUSO MARIA CATENA , RAIMONDI CRISTINA , NOTO LAURA DI , BONGIOVANNI ALBERTO , ACCARDO ANGELA , CANDORE GIUSEPPINA , PALMERI LAURA , VERNA ROBERTO , CARUSO CALOGERO , LIO DOMENICO , PALMERI SERGIO
Published: February 2007

Abstract:  It is well established that cancer arises in chronically inflamed tissue, and this is particularly notable in the gastrointestinal tract. Classic examples include Helicobacter pylori–associated gastric cancer, hepatocellular carcinoma, and inflammatory bowel disease–associated colorectal cancer. Growing evidence suggests that these associations might be not casual findings. Focusing on individual cytokines has generated evidence that anti‐inflammatory cytokine interleukin (IL)‐10 and transforming growth factor‐beta1 (TGF‐β1) may have a complex role in gastrointestinal carcinogenesis. As an example, IL‐10‐deficient mice develop severe atrophic gastritis and a chronic enterocolitis, developing colorectal cancer similar to human inflammatory bowel disease–associated neoplasia. TGF‐β1 is a multifunctional signaling molecule with a wide array of roles. Animal experiments suggest that TGF‐β1 plays a biphasic role in carcinogenesis by protecting against the early formation of benign epithelial growths, but promoting a significant stimulation of tumor growth invasion and metastasis during tumor progression. We assessed association of functional polymorphisms (–1082G/A; –592C/A) and TGF‐β1 (–509C/T; +869C/T) influencing the IL‐10 production to colorectal cancer risk in a case–control study of 62 patients and 124 matched controls. No significant differences were observed among cancer patients and controls for IL‐10 –1082G/A; –592C/A genotype frequencies. Evaluation of odds ratios (OR) for the TGF‐β1 +869C/T genotypes showed a significant increased risk for individuals bearing +869CC genotype compared to +869CT‐ and +869TT‐positive individuals. These results suggest that the +869C allele, responsible for a Leu→Pro substitution in the signal peptide sequence of the TGF‐β1 protein, may have a predisposing role in the development of colorectal cancer.
Adjuvant Diet to Improve Hormonal and Metabolic Factors Affecting Breast Cancer Prognosis
Authors: BERRINO FRANCO , VILLARINI ANNA , DE PETRIS MICHELA , RAIMONDI MILENA , PASANISI PATRIZIA
Published: February 2007

Abstract:  Western lifestyle, characterized by reduced physical activity and a diet rich in fat, refined carbohydrates, and animal protein is associated with high prevalence of overweight, metabolic syndrome, insulin resistance, and high plasma levels of several growth factors and sex hormones. Most of these factors are associated with breast cancer risk and, in breast cancer patients, with increased risk of recurrences. Recent trials have proven that such a metabolic and endocrine imbalance can be favorably modified through comprehensive dietary modification, shifting from Western to Mediterranean and macrobiotic diet.
Estrogen Action in Neuroprotection and Brain Inflammation
Authors: POZZI SILVIA , BENEDUSI VALERIA , MAGGI ADRIANA , VEGETO ELISABETTA
Published: February 2007

Abstract:  The fertile period of women's life compared to menopause is associated with a lower incidence of degenerative inflammatory diseases. In brain, estrogens ameliorate brain performance and have positive effects on selected neural pathologies characterized by a strong inflammatory component. We thus hypothesized that the inflammatory response is a target of estrogen action; several studies including ours provided strong evidence to support this prediction. Microglia, the brain's inflammatory cells, and circulating monocytes express the estrogen receptors ER‐α and ER‐β and their responsiveness in vivo and in vitro to pro‐inflammatory agents, such as lipopolysaccharide (LPS), is controlled by 17β‐estradiol (E2). Susceptibility of central nervous system (CNS) macrophage cells to E2 is also preserved in animal models of neuroinflammatory diseases, in which ER‐α seems to be specifically involved. At the molecular level, induction of inflammatory gene expression is blocked by E2. We recently observed that, differently from conventional anti‐inflammatory drugs, E2 stimulates a nongenomic event that interferes with the LPS signal transduction from the plasma membrane to cytoskeleton and intracellular effectors, which results in the inhibition of the nuclear translocation of NF‐κB, a transcription factor of inflammatory genes. Interference with NF‐κB intracellular trafficking is selectively mediated by ER‐α. In summary, evidence from basic research strongly indicates that the use of estrogenic drugs that can mimic the anti‐inflammatory activity of E2 might trigger beneficial effects against neurodegeneration in addition to carrying out their specific therapeutic function.
Multi-Institutional Reciprocal Validation Study of Computed Tomography Predictors of Suboptimal Primary Cytoreduction in Patients With Advanced Ovarian Cancer
Authors: Axtell Allison E. , Lee Margaret H. , Bristow Robert E. , Dowdy Sean C. , Cliby William A. , Raman Steven , Weaver John P. , Gabbay Mojan , Ngo Michael , Lentz Scott , Cass Ilana , Li Andrew J. , Karlan Beth Y. , Holschneider Christine H.
Published: February 2007

Purpose

Identify features on preoperative computed tomography (CT) scans to predict suboptimal primary cytoreduction in patients treated for advanced ovarian cancer in institution A. Reciprocally cross validate the predictors identified with those from two previously published cohorts from institutions B and C.

Patients and Methods

Preoperative CT scans from patients with stage III/IV epithelial ovarian cancer who underwent primary cytoreduction in institution A between 1999 and 2005 were retrospectively reviewed by radiologists blinded to surgical outcome. Fourteen criteria were assessed. Crossvalidation was performed by applying predictive model A to the patients from cohorts B and C, and reciprocally applying predictive models B and C to cohort A.

Results

Sixty-five patients from institution A were included. The rate of optimal cytoreduction (≤ 1 cm residual disease) was 78%. Diaphragm disease and large bowel mesentery implants were the only CT predictors of suboptimal cytoreduction on univariate (P < .02) and multivariate analysis (P < .02). In combination (model A), these predictors had a sensitivity of 79%, a specificity of 75%, and an accuracy of 77% for suboptimal cytoreduction. When model A was applied to cohorts B and C, accuracy rates dropped to 34% and 64%, respectively. Reciprocally, models B and C had accuracy rates of 93% and 79% in their original cohorts, which fell to 74% and 48% in cohort A.

Conclusion

The high accuracy rates of CT predictors of suboptimal cytoreduction in the original cohorts could not be confirmed in the cross validation. Preoperative CT predictors should be used with caution when deciding between surgical cytoreduction and neoadjuvant chemotherapy.
Mean-Variance-Skewness Portfolio Performance Gauging: A General Shortage Function and Dual Approach
Authors: Briec Walter , Kerstens Kristiaan , Jokung Octave
Published: February 2007

This paper proposes a nonparametric efficiency measurement approach for the static portfolio selection problem in mean-variance-skewness space. A shortage function is defined that looks for possible increases in return and skewness and decreases in variance. Global optimality is guaranteed for the resulting optimal portfolios. We also establish a link to a proper indirect mean-variance-skewness utility function. For computational reasons, the optimal portfolios resulting from this dual approach are only locally optimal. This framework permits to differentiate between portfolio efficiency and allocative efficiency, and a convexity efficiency component related to the difference between the primal, nonconvex approach and the dual, convex approach. Furthermore, in principle, information can be retrieved about the revealed risk aversion and prudence of investors. An empirical section on a small sample of assets serves as an illustration.
Effect of pitting corrosion on capacity of prestressing wires
Authors: Darmawan M. S. , Stewart M. G.
Published: February 2007

The present paper describes accelerated corrosion test results and the development of a probabilistic model to predict the depth and variability of pitting for pretensioned prestressing wires and strands subject to pitting corrosion. From the accelerated corrosion tests in a chloride-concrete environment the mode of wire failure is studied, and the spatial distribution of maximum pit depth along wires for various lengths is obtained. The analysis shows that the maximum pit-depth distribution of prestressing wires can be represented by the Gumbel extreme value distribution. This model can be extended to predict the distribution of maximum pit depth for any length of wire, corrosion rate and time of exposure in real concrete structures. This information can be used to predict minimum cross-sectional area of a corroded wire, wire capacity and the effect of pitting corrosion on the safety of pretensioned prestressed concrete structures.
Pixel‐isolated liquid‐crystal mode by using a patterned anisotropic phase separation for flexible LCDs
Authors: Jang Se‐Jin , Jung Jong‐Wook , Kim Hak‐Rin , Jin Min Young , Lee You‐Jin , Kim Jae‐Hoon
Published: February 2007

Abstract— A pixel‐isolated liquid‐crystal (PILC) mode for enhancing the mechanical stability of flexible‐display applications is proposed. Because liquid‐crystal (LC) molecules in this mode are isolated in each pixel by patterned or phase‐separated microstructures, and the two substrates are tightly attached to each other by a solidified polymer layer, the LC alignment is stable against external pressure, and the cell gap of our structure is uniformly preserved against bending deformation of the plastic substrates. The mechanical stability of the PILC structure having plastic substrates was tested for its electro‐optic properties.
Floral development in Aphandra (Arecaceae)
Authors: Barfod Anders S. , Uhl Natalie W.
Published: February 2007

The organogenesis of staminate flower clusters and flowers and some observations on the corresponding pistillate structures of Aphandra natalia are described and compared with those of the other two genera in the Phytelephantoideae (Arecaceae). In Aphandra, staminate flowers are borne in monopodial clusters of mostly four (1–6) flowers. Each flower is surrounded by two pairs of subopposite bracteoles and has two rather indistinctly four‐parted whorls of perianth parts. Stamen primordia arise on a shallow apical dome and then centrifugally down the sides of a long, angled, and laterally flattened receptacle. Immediately before the staminate bud opens, the floral receptacle below the androecium rapidly elongates, becoming funnel‐shaped, with the bracteoles and a perianth sheath adnate to it forming a pseudopedicel. Epidermal and subepidermal layers of these pseudopedicels split at anthesis and release a great number of raphide idioblasts that resemble the pollen grains in shape and size. It is hypothesized that the idioblasts deter pollen feeding or ovidepositing insects. The phylogenetic implications of these findings are important within the Phytelephantoideae and among palms in general.
Structural homology and developmental transformations associated with ovary diversification in Lithophragma (Saxifragaceae)
Authors: Kuzoff Robert K. , Hufford Larry , Soltis Douglas E.
Published: February 2007

Lithophragma, comprising only ten species, encompasses a remarkable diversity of ovary positions, reported to range from inferior to superior. The structural homology of the gynoecium and developmental transformations associated with ovary diversification are investigated for Lithophragma. Scanning electron and light microscopy indicate that all species of Lithophragma have epigynous flowers. Lithophragma campanulatum, L. glabrum, and L. heterophyllum have ovaries that externally appear nearly superior, but are actually shallowly inferior or “pseudosuperior.” The inferior ovaries of Lithophragma species can be conceptually divided into superior and inferior regions that meet at the point of perianth and androecial insertion. Static and ontogenetic allometry reveal that across the species of Lithophragma the lengths of these two ovary regions are coordinated. Ovary regions in mature flowers display an approximately linear relationship that can be expressed through the allometric equation SL = −0.5314 IL + 2.0348 (where SL and IL are the lengths of the superior and inferior regions of the ovary, respectively; r2 = 0.7683, df = 35, P = 2.45 × 10−12). Mapping ontogenetic allometries onto a recent phylogeny for Lithophragma shows that ovary position evolution is bidirectional and has shifted toward greater superiority in some species and greater inferiority in others.
Seasonal conductivity and embolism in the roots and stems of two clonal ring‐porous trees,Sassafras albidum(Lauraceae) andRhus typhina(Anacardiaceae)
Authors: Jaquish Laura L. , Ewers Frank W.
Published: February 2007

Seasonal xylem (wood) conductivity and embolism (air blockage) patterns were monitored in roots vs. stems of two clonal ring‐porous tree species,Sassafras albidumandRhus typhina, throughout 1996 and 1997. Stems of both species were 100% embolized in the early spring and became conductive by late June following leaf expansion and maturation of new earlywood vessels. Dyes indicated the stem conduction was restricted almost exclusively to the current year's growth ring. Stems became totally embolized again by early October, before the first freezing temperatures. In contrast, woody roots of both species maintained low embolism values, many conductive growth rings, and high conductivity values regardless of the season. No positive root pressures were detected in either species. The mean frost depth (204 ± 11 mm) was deeper than all sampled roots ofRhusand 47% of sampled roots ofSassafras. The roots that had been in frozen soil either avoided embolism altogether or they were able to reverse embolism by a mechanism other than positive root pressures.
An expanded role for the TWN1 gene in embryogenesis: defects in cotyledon pattern and morphology in the  twn1 mutant of Arabidopsis (Brassicaceae)
Authors: Vernon Daniel M. , Hannon Michael J. , Le MyPhuong , Forsthoefel Nancy R.
Published: February 2007

The suspensor is a specialized basal structure that differentiates early in plant embryogenesis to support development of the embryo proper. Suspensor differentiation in Arabidopsis is maintained in part by the TWIN1 (TWN1) gene, which suppresses embryogenic development in suspensor cells: twn1 mutants produce supernumerary embryos via suspensor transformation. To better understand mechanisms of suspensor development and further investigate the function of TWN1, we have characterized late‐embryo and post‐embryonic development in the twn1 mutant, using seedling culture, microscopy, and genetics. We report here that the twn1 mutation disrupts cotyledon number, arrangement, and morphology and occasionally causes partial conversion of cotyledons into leaves. These defects are not a consequence of suspensor transformation. Thus, in addition to its basal role in suspensor differentiation, TWN1 influences apical pattern and morphology in the embryo proper. To determine whether other genes can similarly affect both suspensor and cotyledon development, we looked for twinning in Arabidopsis mutants previously identified by their abnormal cotyledon phenotypes. One such mutant, amp1, produced a low frequency of twin embryos by suspensor transformation. Our results suggest that mechanisms that maintain suspensor identity also function later in development to influence organ formation at the embryonic shoot apex. We propose that TWN1 functions in cell communication pathways that convey local positional information in both the apical and basal regions of the Arabidopsis embryo.
Comparative evaluation of vessel elements in S alix spp. (Salicaceae) endemic to the Athabasca sand dunes of northern Saskatchewan, Canada
Authors: Cooper Ranessa L. , Cass David D.
Published: February 2007

Vessel element (VE) characters, including density, lumen diameter, length, and clustering, were evaluated using light and scanning electron microscopy in four endemic Salix taxa from the Lake Athabasca sand dunes in northern Saskatchewan, Canada. These data were compared with the widespread putative sister species for each endemic. Endemic taxa exhibited similar VE densities as compared to their associated sister species. Salix brachycarpa var. brachycarpa and its derived endemic, var. psammophila, had the highest VE density values of all endemic–progenitor pairs in this study. Values for VE lumen diameter and VE length were significantly different in some of the species pairs. Lumen diameter of the endemic S. planifolia ssp. tyrrelli was significantly less than that of its widespread sister species, ssp. planifolia. Salix turnorii had significantly greater values for both VE lumen diameter and length than its progenitor, S. lutea. Vessel element clustering did not differ significantly between endemic and progenitor taxa with the exception of S. silicicola and its arctic progenitor, S. alaxensis. Structural differences for these endemic willows appear related to their open sand habitat, and taxonomic implications for endemic–progenitor pairs are discussed.
A genetic analysis of hydrologically dispersed seeds of Hibiscus moscheutos (Malvaceae)
Authors: Kudoh Hiroshi , Whigham Dennis F.
Published: February 2007

The dispersal of floating seeds in wetland habitats should influence the genetic characteristics of plant metapopulations. We examined gene flow of a hydrochorous wetland macrophyte, Hibiscus moscheutos L. (Malvaceae), by analyzing allozyme variation in current‐year floating‐seed populations. The genetic composition of floating seeds was compared to the genetic composition of established populations of H. moscheutos that had been previously analyzed in the same areas. The F statistics demonstrated that genetic structuring among floating‐seed populations was weak or absent, indicating that seeds from source populations were thoroughly mixed. Floating‐seed populations had an excess of homozygotes, a different situation than had previously been found in established populations. The exchange of seeds was greatest among H. moscheutos populations that were adjacent to a tidal stream. We conclude that populations adjacent to the tidal streams are part of a metapopulation that serves as a reserve of genetic variation in the system. Although established populations of H. moscheutos that are not close to the tidal stream are relatively isolated genetically, we found evidence that they also contribute to the floating‐seed populations within the estuary.
Genetic relationships and population structure of the endangered Steamboat buckwheat,Eriogonum ovalifoliumvar.williamsiae(Polygonaceae)
Authors: Archibald Jenny K. , Wolf Paul G. , Tepedino V. J. , Bair Janet
Published: February 2007

Eriogonum ovalifoliumvar.williamsiae(Steamboat buckwheat) is a narrow endemic subshrub, known from a single locality in Washoe County, Nevada. We examined genetic structure of the only known population by analyzing patterns of allozyme variation. Our results suggest that Steamboat buckwheat has high genetic variability, with levels of variation similar to that typical of a widespread species rather than a narrow endemic. Genotype frequencies suggest that mating is random. We detected no genetic subdivision of the population. Several clones spanning up to 67 cm were found, but we do not know if such clones are common. We used allozyme data to assess the genetic similarity of var.williamsiaeto five other varieties ofE. ovalifolium.All six varieties are very similar allozymically with var.williamsiaebeing the most similar to the widespread var.ovalifolium.Although var.williamsiaeand var.ovalifoliumare morphologically distinct, their genetic similarity warrants further study to determine whether or not they should be treated as separate taxa. Evidence of male sterility in var.williamsiaeplus other data leads us to hypothesize that this taxon might be either a hybrid or undergoing cytoplasmic introgression. Information gathered from this study, in concert with ongoing work on the breeding system of Steamboat buckwheat, should be helpful in forming management strategies for this plant.
Molecular phylogenetics of Acacia (Fabaceae: Mimosoideae) based on the chloroplast MATK coding sequence and flanking TRNK intron spacer regions
Authors: Miller Joseph T. , Bayer Randall J.
Published: February 2007

The tribe Acacieae (Fabaceae: Mimosoideae) contains two genera, the monotypic African Faidherbia and the pantropical Acacia, which comprise about 1200 species with over 950 confined to Australia. As currently recognized, the genus Acacia is subdivided into three subgenera: subg. Acacia, subg. Aculeiferum, and the predominantly Australian subg. Phyllodineae. Morphological studies have suggested the tribe Acacieae and genus Acacia are artificial and have a close affinity to the tribe Ingeae. Based on available data there is no consensus on whether Acacia should be subdivided. Sequence analysis of the chloroplast trnK intron, including the matK coding region and flanking noncoding regions, indicate that neither the tribe Acacieae nor the genus Acacia are monophyletic. Two subgenera are monophyletic; section Filicinae of subgenus Aculeiferum does not group with taxa of the subgenus. Section Filicinae, eight Ingeae genera, and Faidherbia form a weakly supported paraphyletic grade with respect to subg. Phyllodineae. Acacia subg. Aculeiferum (s. s.) is sister to the grade. These data suggest that characters currently used to differentiate taxa at the tribal, generic, and subgeneric levels are polymorphic and homoplasious in cladistic analyses.
Selective seed abortion increases offspring survival in Cynoglossum officinale (Boraginaceae)
Authors: Melser Chantal , Klinkhamer Peter G. L.
Published: February 2007

Selective embryo abortion is one of the evolutionary explanations for the surplus of ovules found in many plant species. To manipulate the level of embryo abortion, we removed ovules and applied nutrients to plants of Cynoglossum officinale (Boraginaceae) after they started to flower. From these two treatments and a control series, seeds were collected, germinated, and transplanted in the field to assess the quality of the resulting offspring. Nutrient addition did not increase the number of seeds per flower significantly. Fewer embryos were aborted in the ovule removal treatment. The seeds produced in the ovule removal treatment had a significantly greater mass and significantly lower survival than the offspring from the control group. This difference in survival indicates that offspring of lower quality are selectively aborted in the control group. Offspring from the nutrient addition treatment survived longer. The offspring of the treatments did not differ significantly from the control group in growth. Simple mathematical calculations, based on the differences in offspring quality that we found, indicate that the selective abortion hypothesis can be an important factor explaining the advantage of the “surplus production” of ovules.
Molecular phylogenetics of Melastomataceae and Memecylaceae: implications for character evolution
Authors: Clausing G. , Renner S. S.
Published: February 2007

Melastomataceae are among the most abundant and diversified groups of plants throughout the tropics, but their intrafamily relationships and morphological evolution are poorly understood. Here we report the results of parsimony and maximum likelihood (ML) analyses of cpDNA sequences from therbcLandndhFgenes and therpl16intron, generated for eight outgroups (Crypteroniaceae, Alzateaceae, Rhynchocalycaceae, Oliniaceae, Penaeaceae, Myrtaceae, and Onagraceae) and 54 species of melastomes. The sample represents 42 of the family's currently recognized ∼150 genera, the 13 traditional tribes, and the three subfamilies, Astronioideae, Melastomatoideae, and Memecyloideae (= Memecylaceae DC.). Parsimony and ML yield congruent topologies that place Memecylaceae as sister to Melastomataceae.Pternandra, a Southeast Asian genus of 15 species of which five were sampled, is the first‐ branching Melastomataceae. This placement has low bootstrap support (72%), but agrees with morphological treatments that placedPternandrain Melastomatacaeae because of its acrodromal leaf venation, usually ranked as a tribe or subfamily. The interxylary phloem islands found in Memecylaceae andPternandra, but not most other Melastomataceae, likely evolved in parallel becausePternandraresembles Melastomataceae in its other wood characters. A newly discovered plesiomorphic character inPternandra, also present in Memecylaceae, is a fibrous anther endothecium. Higher Melastomataceae lack an endothecium as do the closest relatives of Melastomataceae and Memecylaceae. The next deepest split is between Astronieae, with anthers opening by slits, and all remaining Melastomataceae, which have anthers opening by pores. Within the latter, several generic groups, corresponding to traditional tribes, receive solid statistical support, but relationships among them, with one exception, are different from anything predicted on the basis of morphological data. Thus, Miconieae and Merianieae are sister groups, and both are sister to a trichotomy of Bertolonieae, Microlicieae + Melastomeae, and Dissochaeteae + Blakeeae. Sonerileae/Oxysporeae are nested within Dissochaeteae, Rhexieae within Melastomeae, and African and Asian Melastomeae within neotropical Melastomeae. These findings have profound implications for our understanding of melastome morphological evolution (and biogeography), implying, for example, that berries evolved from capsules minimally four times, stamen connectives went from dorsally enlarged to basal/ventrally enlarged, and loss of an endothecium preceded poricidal dehiscence.
Molecular systematics of the Brassicaceae: evidence from coding plastidic matK and nuclear Chs sequences
Authors: Koch Marcus , Haubold Bernhard , Mitchell‐Olds Thomas
Published: February 2007

Phylogenetic relationships were inferred using nucleotide sequence variation of the nuclear‐encoded chalcone synthase gene (Chs) and the chloroplast gene matK for members of five tribes from the family Brassicaceae to analyze tribal and subtribal structures. Phylogenetic trees from individual data sets are mostly in congruence with the results from a combined matK‐Chs analysis with a total of 2721 base pairs, but with greater resolution and higher statistical support for deeper branching patterns. The analysis indicates that tribes Lepidieae, Arabideae, and Sisymbrieae are not monophyletic. Among taxa under study four different lineages each were detected in tribes Arabideae and Lepidieae, interspersed with taxa from tribes Sisymbrieae, Hesperideae, and Brassiceae. It is concluded that tribe Brassiceae might be the only monophyletic group of the traditional tribes. From our data we estimated several divergence times for different lineages among cruciferous plants: 5.8 mya (million years ago) for the Arabidopsis–Cardaminopsis split, 20 mya for the Brassica–Arabidopsis split, and ∼40 mya for the age of the deepest split between the most basal crucifer Aethionema and remaining cruciferous taxa.
Trans‐Atlantic dispersal and phylogeography of Cerastium arcticum (Caryophyllaceae) inferred from RAPD and SCAR markers
Authors: Hagen Aslaug R. , Giese Henriette , Brochmann Christian
Published: February 2007

Cerastium arcticum is an autogamous pioneer species with a distribution limited to the North Atlantic region. It has been suggested that such species must have survived in ice‐free refugia on both sides of the Atlantic throughout the last, or even several, of the Pleistocene glaciations, because they lack special adaptations for long‐distance dispersal. To address the possibility for recent trans‐Atlantic dispersal of C. arcticum, we analyzed random amplified polymorphic DNA (RAPD) and sequence characterized amplified region (SCAR) differentiation among 26 populations of this high‐polyploid species. Three SCAR markers were obtained that verified the main patterns identified in the RAPD analysis. Eighty‐four multilocus RAPD phenotypes were observed in the 126 plants analyzed, based on 35 polymorphic markers. Multivariate analyses and analyses of molecular variance (AMOVAs) identified two highly divergent groups of populations: one arctic group (western and eastern Greenland, and the archipelagos of Svalbard and Franz Josef Land) and one nonarctic group (southern and northern Norway, and Iceland), indicating that C. arcticum is composed of two lineages with different evolutionary histories. However, there was little geographic structuring within each lineage, in spite of the fact that both lineages are disjunctly distributed across the Atlantic. Occurrence of very similar, in some cases even identical RAPD multilocus phenotypes on both sides of the Atlantic in this autogamous allopolyploid is most probably caused by postglacial dispersal. The present geographic distribution of C. arcticum may thus have been established after trans‐Atlantic expansion from two Weichselian refugia, one for each evolutionary lineage. Unexpectedly, the level of intrapopulational variation increased towards the north. This may reflect that interpopulational migration is most extensive in the treeless arctic environment, where the species has a more continuous distribution than in the more southerly areas.
Floral development in Schotia and Cynometra (Leguminosae: Caesalpinioideae: Detarieae)
Authors: Tucker Shirley C.
Published: February 2007

Floral development was compared among several relatively unspecialized taxa in caesalpinioid tribe Detarieae: Cynometra webberi, an undescribed species of Cynometra, and three species of Schotia. These share a relatively unspecialized caesalpinioid flower type with no loss of organs, but some organ suppression. They also share the following characters: relatively small bracteoles in early stages, a circular floral apex, helical sepal initiation, and a nonmedian abaxial position of the first sepal initiated. Floral symmetry is radial. Order of initiation is helical among sepals in all. Order of petal initiation varies: helical in Schotia afra, unidirectional in Schotia brachypetala and S. latifolia, and simultaneous in Cynometra. Stamens are initiated unidirectionally in all except in the outer stamen whorl of Schotia afra, which is helical. Overlap of time of initiation between whorls occurs in S. brachypetala, S. latifolia, and Cynometra. The carpel initiates concurrently with the petals or directly thereafter in all. A tetramerous calyx results from fusion of the two upper (adaxial) sepal primordia. The carpel initiates ovules before marginal closure in both genera. Organ suppression includes one or two petals in Schotia and sometimes one in Cynometra.
Molecular phylogeny of Coelogyne (Epidendroideae; Orchidaceae) based on plastid RFLPS, matK, and nuclear ribosomal ITS sequences: evidence for polyphyly
Authors: Gravendeel Barbara , Chase Mark W. , de Vogel Ed F. , Roos Marco C. , Mes Ted H. M. , Bachmann Konrad
Published: February 2007

To evaluate the monophyly of Coelogyne (Epidendroideae; Orchidaceae) and reveal sectional relationships and relations to allied genera in subtribe Coelogyninae, we collected PCR (polymerase chain reaction) amplified restriction fragment length polymorphisms (RFLPs) from 11 plastid regions for 42 taxa (28 Coelogyne species and 14 representatives of other genera) and three outgroups from Bletiinae and Thuniinae. We also sequenced a large portion of the plastid trnK intron (mostly matK) and the nuclear ribosomal DNA internal transcribed spacers ITS1 and ITS2 (including the 5.8S gene). Separate phylogenetic analyses on each data set using maximum parsimony produced mainly congruent (except for the position of Panisea) but weakly supported clades. Parsimony analysis of the combined data clearly identified three main clades in Coelogyninae. Whereas Coelogyninae are monophyletic, Coelogyne is polyphyletic, with species falling into at least two well‐supported clades. The utility of morphological characters used in previous classifications was explored by reconstructing character state evolution on one of the four molecular trees. Lip base and petal shape were homoplasious, whereas ovary indumentum and flower number were congruent with well‐supported groups. The implications of our results for the classification of Coelogyne are discussed, and a reorganization of the genus by including Neogyna and Pholidota and removing several species is proposed.
Functional analysis of synchronous dichogamy in flowering rush, Butomus umbellatus (Butomaceae)
Authors: Bhardwaj Michael , Eckert Christopher G.
Published: February 2007

Dichogamy is one of the most widespread floral mechanisms in flowering plants and is thought to have evolved to reduce interference between pollen import and export within flowers, especially self‐pollination. Self‐pollination between flowers may also be reduced if dichogamy is synchronous among flowers on an inflorescence. The analysis of dichogamy at both levels requires that the sexual phases of individual flowers be defined functionally in terms of pollen deposition and removal. We conducted morphological and functional analyses to investigate the degree of dichogamy within flowers and the synchronicity of dichogamy between flowers within inflorescences in an emergent, aquatic monocot, flowering rush (Butomus umbellatus). Based on daily observations of the development of marked flowers, data on the schedule of anther dehiscence within flowers, and repeat surveys of floral sex ratios in three populations, individual flowers appear to be strictly protandrous. On average, each flower spends ∼1 d in each of male and female phases with an intervening 1‐d neuter phase during which there is no available pollen in anthers and stigmas are not yet exposed to receive pollen. Morphological criteria used to delimit the beginning and end of each of these three sex phases were validated by quantifying the temporal schedule of pollen removal from anthers and pollen deposition on stigmas. Experimental pollinations showed that the morphological changes marking the end of female phase are hastened by pollen deposition. At the umbel level, synchronous development within sequential cohorts of flowers reduced overlap of male and female sexual phases between flowers. On average (±1 SE), 72 ± 3% of flowers completed their female phase while no other flowers on the same umbel were in male phase. Computer simulations of umbel development showed that this value is significantly higher than expected if the timing of flower development within umbels was random (30 ± 1%). Surveys of floral sex ratios in three populations revealed that 87% of umbels were either unisexual male or female at any given time. Pollinators usually visited more than one flower in sequence when foraging on umbels, suggesting that synchronous dichogamy may be an adaptation to avoid geitonogamy. The adaptiveness of both flower‐ and umbel‐level dichogamy is also suggested because both traits are expressed to a lesser extent in obligately clonal, triploid populations, where flowers do not make seeds and hence floral adaptations are not maintained by natural selection.
Adaptation of Senecio vulgaris (Asteraceae) to ruderal and agricultural habitats
Authors: Leiss Kirsten A. , Müller‐Schärer Heinz
Published: February 2007

Adaptation of the annual plant Senecio vulgaris to ruderal and agricultural habitats was investigated. We expected S. vulgaris to be adapted to the agricultural habitat through nutrient‐specific differentiation of relatively few genotypes responding to the generally high homogenous nutrient levels at the agricultural habitat caused by constant fertilization. To assess adaptation of S. vulgaris, vegetative and reproductive responses of seed families from various populations of agricultural and ruderal habitats, grown in the greenhouse at high and low nutrient levels, were compared. Data were analyzed with a three‐level nested ANOVA based on the levels habitat, population, and family. A significant habitat effect indicated that S. vulgaris from ruderal and agricultural habitats were genetically different with plants from the agricultural habitat having larger leaves and a higher reproduction. A significant habitat by nutrient effect showed a stronger response of reproduction to nutrients at the agricultural habitat, suggesting that genetic differentiation among habitats is nutrient‐specific. Contrary to expectations, only the agricultural habitat showed genetic diversity of S. vulgaris. Results suggest that nutrient levels at the agricultural habitat are more heterogeneous as generally proposed leading to a relatively high genetic variation.
Age and biogeography of major clades in Liliales
Authors: Vinnersten Annika , Bremer Kåre
Published: February 2007

A robust phylogeny of 40 genera and all seven families of the Liliales based onrbcLsequences was dated by the mean branch‐length method of Bremer and Gustafsson and by Sanderson's nonparametric rate smoothing. The basal node was set to 82 million years (my) from the results of a previous more extensive dating involving all monocots. Confidence intervals for the age estimates were generated by bootstrap analysis. The results indicate that four well‐supported clades of Liliales date back to the Cretaceous ∼65 million years ago (mya), Campynemataceae, Melanthiaceae, Smilacaceae + Liliaceae, and Alstroemeriaceae + Luzuriagaceae + Colchicaceae. Aspects of historical biogeography were investigated by dispersal–vicariance analysis. Several dispersal and vicariance events were found to coincide with Late Cretaceous–Early Tertiary changes in continental interconnections. The study contains the first published sequence ofCampynemanthe, supporting the Campynemataceae as a monophyletic group.
Bt corn has a higher lignin content than non‐Bt corn
Authors: Saxena Deepak , Stotzky G.
Published: February 2007

Bt corn has been genetically modified to express the Cry1Ab protein of Bacillus thuringiensis to kill lepidopteran pests. Fluorescence microscopy and staining with toluidine blue indicated a higher content of lignin in the vascular bundle sheaths and in the sclerenchyma cells surrounding the vascular bundle in all ten Bt corn hybrids, representing three different transformation events, studied than of their respective non‐Bt isolines. Chemical analysis confirmed that the lignin content of all hybrids of Bt corn, whether grown in a plant growth room or in the field, was significantly higher (33–97% higher) than that of their respective non‐Bt isolines. As lignin is a major structural component of plant cells, modifications in lignin content may have ecological implications.