bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE GENESIS OF SIZE HIERARCHIES IN SEEDLING POPULATIONS OF IMPATIENS CAPENSIS MEERB.
Authors: WALLRE D. M. 
Published: May 2006

SummaryIn 1978 and 1980 I planted 660 and 900 seeds of Impatiens capensis Meerb. at four densities in the greenhouse to examine how variation in plant performance is generated. I noted seed weight, seed type (cleistogamous or chasmogamous), maternal parent, and population of origin, and monitored emergence date, cotyledon area, the biomass of competitors within the same flat, and the final size reached by the seedlings after 63 to 80 d of growth. Larger seeds tended to germinate sooner, as did seeds derived from chasmogamous flowers. Seeds from northern populations took longer to germinate. Seeds from different maternal parents also germinated at different rates. Cotyledon area strongly depended on seed weight, and, to a lesser extent, germination date. Maternal parent and seed type significantly affected cotyledon area in 1980.Plant density and cotyledon area influenced final size the most, but almost every factor proved to be statistically significant. As expected, earlier emerging seedlings with larger cotyledons growing at the lowest density grew into the largest plants. I applied path analysis to summarize the interactions among the continuous variables and to disentangle direct from indirect causal effects. This technique revealed that seed weight enhanced performance primarily through its effects on emergence date and cotyledon area. Chasmogamous seedlings outperformed cleistogamous seedlings, and their advantage was expressed during most phases of growth. Together, the predictor variables accounted for over four‐fifths of the total variation in final size.The inequality of plant sizes, as measured by the Gini coefficient, increased appreciably during the course of the experiment. There was no simple relation to density, however, suggesting that both intrinsic differences in growth rate, and competitive dominance and supression fuel the establishment of size hierarchies.
ON THE OCCURRENCE OF BRANCHED AND SWOLLEN RHIZOIDS IN BRITISH HEPATICS: THEIR RELATIONSHIPS WITH THE SUBSTRATUM AND ASSOCIATIONS WITH FUNGI
Authors: POCOCK K. , DUCKETT J. G. 
Published: May 2006

SummaryThe occurrence of branched and swollen rhizoids was investigated in 72–5 % of British hepatics (206 of the 284 species). Branched rhizoids are widespread in the Jungermanniales (100 of the 169 species) but are restricted to the Metzgeriineae in the Metzgeriales. They were not detected in the Marchantiidae. Terminal swellings, particularly well developed in the Lepidoziineae and Cephaloziineae, were found in 33 species in the Jungermanniales.Rhizoid branching is associated with contact with a range of substrata whereas swollen rhizoids, exclusive to species growing on peat and rotten wood, are always associated with fungal hyphae. In some species, the hyphae probably derive from the fungal zone in the stem of the hepatic but, in others, they more likely come from repeated external invasions. The function of branched rhizoids is almost certainly anchorage whereas the swollen tips may well be absorbtive, probably involving the fungus as an intermediary.Branched and swollen rhizoids are particularly prominent on flagellar shoots but are most developed on leafless underground stems. These hitherto undescribed subterranean axes which extend to depths of up to 20 cm in several members of the Lepidoziaceae and Cephaloziaceae may be important organs of perennation enabling plants to survive drought and fire.
THE ELM DECLINE AT PAWLAW MIRE: AN ANTHROPOGENIC INTERPRETATION
Authors: STURLUDOTTIR SIGRUN A. , TURNER JUDITH 
Published: May 2006

SummaryA fine‐resolution pollen diagram has been prepared from across the elm decline at Pawpaw Mire, 462 m OD, in the northern Pennies of England. It covers 25 cm with 01 cm thick samples at intervals varying from 08 to 01 cm in different parts of the diagram. It is estimated that each sample contains the pollen produced during an average of one to two seasons. There is evidence that the woodland vegetation was being managed by the local mesolithic population throughout the four centuries or so represented and although other factors may have contributed, the elm decline at this site can be explained satisfactorily in terms of the cumulative effect of this mesolithic activity on the soils of the area.
LEAF DIFFUSIVE RESISTANCE AND WATER ECONOMY IN CARBON DIOXIDE‐ENRICHED RICE PLANTS
Authors: KHAN M. A. H. , MADSEN A. 
Published: May 2006

SUMMARYThe leaf diffusive resistance to the transfer of water vapour and CO2 exchange in rice plants (Oryza sativa L., ev. IR‐20) measured from the late vegetative stage to maturity, varied in response to differing CO2 enrichments. The leaf diffusive resistance of plants treated with 900 μ11−l CO2 ranged from one‐half to twice that of the control plants (330μl l−1 CO2).This difference was more pronounced during the heading and ripening stages. In plants treated with 600 μ1 −1 CO2, the diffusive resistances appeared to be smaller than in the control plants for most of the day. In the diurnal cycles, resistances were highest during the early morning and before sunset, the maximum again occurring in the plants treated with 900μ11 −1 CO2.The rate of transpiration was inversely related to the diffusive resistance, and was 20 to 100% lower in the plants treated with 900 μ1 1−1 CO2 than in the controls, both in the seasonal and diurnal cycles. In plants treated with 600 μ1 1−1 CO2, the rate of transpiration was lower than in the controls in the morning but distinctly higher during the afternoon. However, the integrated total daily transpiration in 600 μ1 1−1 CO2 did not exceed that of the controls. In all cases, CO2‐treated plants, through their increased biomass production and economic yield, appeared to have a higher water use efficiency than the control plants.
DEPRESSION OF GROWTH AND YIELD IN WINTER BARLEY EXPOSED TO SULPHUR DIOXIDE IN THE FIELD
Authors: BAKER C. K. , COLLS J. J. , FULLWOOD A. E. , SEATON G. G. R. 
Published: May 2006

SUMMARYA field exposure system designed for the controlled release of sulphur dioxide (SO2) was used in two contrasting seasons to expose commercial crops of winter bailey (Hordeum vulgare L.) to SO2 concentrations ranging from 40 to 200 ppb [parts per billion (109) by volume] above ambient. During winter and early spring, growth of the plants was depressed at high SO2 concentrations but later recovered; in spring and summer, low concentrations stimulated growth above that of controls, but there was no corresponding increase in grain yield. Yield depression is discussed in relation to SO2 concentration and dose.
STRUCTURAL ASPECTS OF THE PRIMARY TISSUES OF THE CUCURBITA PEPO L. ROOT WITH SPECIAL REFERENCE TO THE PHLOEM
Authors: WARMBRODT ROBERT D. 
Published: May 2006

SummaryThe primary phloem and associated tissues in the root of Cucurbita pepo L. were examined by light and transmission electron microscopy to provide information on the feasibility of symplastic transport from the sieve‐tube members to the cortex in this organ. The structure, distribution and frequency of cytoplasmic connections between the various cell types of the root are reported as well as the cytological characteristics of the various cells. The protoplasts of contiguous cells of the root are joined by various numbers of cytoplasmic connections: plasmodesmata (simple and branched) between parenchymatous elements; pore‐plasmodesmata between sieve‐tube members and parenchymatous elements (companion, phloem parenchyma or pericycle cells in the Cucurbita root); and sieve‐area pores between contiguous sieve elements. The plasmodesmata associated with secondary‐ and tertiary‐state endodermal cells are not constricted by the suberin lamellae. Differences in the frequency of cytoplasmic connections between the various cell types of the primary phloem, pericycle and ground tissue do occur with the highest frequency between sieve‐tube members and companion cells. The results indicate that the structure of the C. pepo root may be compatible with a symplastic pathway of phloem unloading and transport to the cells of the ground tissue.
POPULATION COMPOSITION, GENDER SPECIALIZATION, AND THE ADAPTIVE SIGNIFICANCE OF DISTYLY IN LINUM PERENNE (LINACEAE)
Authors: NICHOLLS MARC S. 
Published: May 2006

SummarySpatial distribution, pollen‐flow and the factors affecting seed‐set were studied for a population of the distylous perennial Linum perenne L. during a single season. The morphs were spatially segregated at the site. Stigmatic pollen loads on long‐style plants comprised 27 to 51 % legitimate pollen and on short‐style plants 0 to 46% legitimate pollen. Most flowers received more legitimate pollen grains than the number theoretically required to fertilize the corresponding number of ovules. Intraflower pollinations accounted for a large proportion of individual stigma loads. There was a weak negative correlation between the distance of the nearest legitimate neighbour and the number of legitimate pollen grains recorded on the stigma. No relationship was established between either the proximity or proportion of legitimate neighbours and seed‐set. Long‐style plants produced less pollen and matured more seeds than short‐style plants. It is suggested that, in the population studied, paternal (pollen) and maternal (seed) investment are unequally divided between the morphs. This may be a common theme associated with heterostyly in plants.
THLASPI CAERULESCENS J. & C. PRESL. (T. ALPESTRE L.) IN BRITAIN
Authors: INGROUILLE M. J. , SMIRNOFF N. 
Published: May 2006

Summary Thlaspi caerulescens J. & C. Presl. (T. alpestre L.) has a restricted and disjunct distribution in Britain. Both on natural and mine sites it is confined to soils contaminated by lead and zinc. Morphological variation occurs both regionally and locally but there is no support from a taxometric cluster analysis for the taxonomic recognition of variants. In experiment the index of zinc tolerance of plants raised from seed was positively correlated with the concentration of zinc in the soils from which the seed parents originated. The distribution of T. caerulescens is discussed in relation to morphological and physiological variation between populations.
PHOTOSYNTHESIS IN VIVO CAN BE LIMITED BY PHOSPHATE SUPPLY
Authors: SIVAK MIRTA N. , WALKER DAVID A. 
Published: May 2006

SummaryMeasurements of photosynthetic CO2 and O2 exchange, and associated chlorophyll fluorescence were made on leaves (from plants grown in complete nutrient medium) while the internal inorganic phosphate concentration was increased or decreased by feeding solutions through the vascular tissue. The data indicate that orthophosphate supply to the chloroplast can, in some circumstances, become the process that limits photosynthesis in vivo.
INDUCTION AND LOSS OF CADMIUM TOLERANCE IN HOLCUS LANATUS L. AND OTHER GRASSES
Authors: BAKER A. J. M. , GRANT C. J. , MARTIN M. H. , SHAW S. C. , WHITEBROOK J. 
Published: May 2006

SummaryThis paper reports the results of an experimental study of Cd tolerance in the grass Holcus lanatus L. The responses of plants from a site aerially contaminated with Cd have been compared with those of plants from metalliferous mine sites and uncontaminated sites, using a range of soil treatments and pretreatments to assess the extent to which Cd tolerance can be affected. Responses in H. lanatus have been compared with those for three other grasses, Agrostis capillaris L., Deschampsia cespitosa (L.) Beauv. and Festuca rubra L., collected from the same sites and propagated as clones on their original soil and uncontaminated soil for three years prior to tolerance testing. Overall, a 13% drop in mean tolerance index was observed; even non‐tolerant clones showed a loss of tolerance when grown in John Innes Potting Compost. These results suggest that H. lanatus is capable of greater phenotypic adjustment than A. capillaris, D. cespitosa and F. rubra and that Cd tolerance in this species can also be partially induced de novo in clones from uncontaminated sites. In H. lanatus there is also an indication that the clones from mines are more stable in their Cd tolerance than that from the aerially polluted site. The possible evolutionary significance of these observations is discussed.
Psychosocial Outcomes and Drug Attributes Affecting Treatment Choice in Men Receiving Sildenafil Citrate and Tadalafil for the Treatment of Erectile Dysfunction: Results of a Multicenter, Randomized, Open-Label, Crossover Study
Authors: Dean John , Hackett Geoffrey I. , Gentile Vincezo , Pirozzi-Farina Furio , Rosen Raymond C. , Zhao Yanli , Warner Margaret R. , Beardsworth Anthony 
Published: May 2006

ABSTRACT

Introduction
Although sildenafil citrate (sildenafil) and tadalafil are efficacious and well-tolerated treatments for erectile dysfunction (ED), preference studies have shown that patients may favor one medication over the other.

Aim
To determine whether psychosocial outcomes differed when men with ED received tadalafil compared with sildenafil.

Main Outcome Measures
Measures included a treatment preference question, Psychological and Interpersonal Relationship Scales (PAIRS), and Drug Attribute Questionnaire.

Methods
Randomized, open-label, crossover study. After a 4-week baseline, men with ED (N = 367; mean age = 54 years; naïve to type 5 phosphodiesterase inhibitor therapy) were randomized: tadalafil for 12 weeks then sildenafil for 12 weeks or vice versa (8-week dose optimization/4-week assessment phases). During dose optimization, patients started with 10 mg tadalafil, or 25 or 50 mg sildenafil and could titrate to their optimal dose (10 or 20 mg tadalafil; 25, 50, or 100 mg sildenafil). Medications were taken as needed. Patients completing both 12-week periods chose which medication to continue during an 8-week extension.

Results
Of 291 men completing both treatment periods, 71% (N = 206) chose tadalafil and 29% (N = 85) chose sildenafil (P &lt; 0.001) for the 8-week extension. When taking tadalafil compared with sildenafil men had higher mean endpoint scores on PAIRS Sexual Self-Confidence (tadalafil = 2.91 vs. sildenafil = 2.75; P &lt; 0.001) and Spontaneity (tadalafil = 3.32 vs. sildenafil = 3.17; P &lt; 0.001) Domains and a lower mean endpoint score on Time Concerns Domain (tadalafil = 2.2 vs. sildenafil = 2.59; P &lt; 0.001). The two most frequently chosen drug attributes to explain treatment preference were ability to get an erection long after taking the medication and firmness of erections. Tadalafil and sildenafil were well tolerated with 12 (3.3%) patients discontinuing for an adverse event.

Conclusions
As measured with PAIRS, men with ED had higher sexual self-confidence and spontaneity and less time concerns related to sexual encounters when treated with tadalafil compared with sildenafil. These psychosocial outcomes may help explain why more men (71%) preferred tadalafil for the treatment of ED in this clinical trial.
Helium pre-enrichment in the first stars
Authors: Chuzhoy Leonid 
Published: May 2006

Abstract
We show that element diffusion can produce large fluctuations in the initial helium abundance of stars. Diffusion time-scale, which in stellar cores is much larger than the Hubble time, can fall below 108 yr in the neutral gas clouds of stellar mass, dominated by collisionless dark matter or with dynamically important radiation or magnetic pressure. Helium diffusion may therefore explain the recent observations of globular clusters, which are inconsistent with initially homogeneous helium distribution.
Common complaints, difficult diagnosis: Multiple myeloma
Authors: Dvorak Colleen 
Published: May 2006

AbstractPurpose: To review the presenting signs and symptoms of multiple myeloma, its pathophysiology, diagnostic evaluation, and treatment options.Data sources: A literature review of research articles and publications by oncology experts who specialize in multiple myeloma, supplemented by a case study.Conclusions: Multiple myeloma is a cancer of the geriatric population, with the average age at diagnosis between 65 and 68 years. As the population of those over age 65 is predicted to double by the year 2050, the incidence of myeloma is expected to increase. Nurse practitioners (NPs) must become familiar with the signs, symptoms, and complications of myeloma for patients to be diagnosed and referred to specialists in a timely manner.Implications for practice: Patients with multiple myeloma often present with vague, common symptoms such as back pain, bony pain, fatigue, and anemia. These symptoms may be treated as separate medical conditions if NPs fail to include multiple myeloma in their differential diagnosis. If NPs are educated on this malignancy, they will have the expertise to look for other signs of the disease such as hypercalcemia, pathological fractures, osteopenia, or renal failure. Without early recognition of multiple myeloma and referrals to oncology specialists, patients are left with a delayed diagnosis and poor symptom control.
Direct Visualization of Red Fluorescent Lipoproteins Indicates Conservation of the Membrane Sorting Rules in the FamilyEnterobacteriaceae
Authors: Lewenza Shawn , Vidal-Ingigliardi Dominique , Pugsley Anthony P. 
Published: May 2006

ABSTRACTChimeras created by fusing the monomeric red fluorescent protein (RFP) to a bacterial lipoprotein signal peptide (lipoRFPs) were visualized in the cell envelope by epifluorescence microscopy. Plasmolysis of the bacteria separated the inner and outer membranes, allowing the specific subcellular localization of lipoRFPs to be determined in situ. When equipped with the canonical inner membrane lipoprotein retention signal CDSR, lipoRFP was located in the inner membrane inEscherichia coli, whereas the outer membrane sorting signal CSSR caused lipoRFP to localize to the outer membrane. CFSR-RFP was also routed to the outer membrane, but CFNSR-RFP was located in the inner membrane, consistent with previous data showing that this sequence functions as an inner membrane retention signal. These four lipoproteins exhibited identical localization patterns in a panel of members of the familyEnterobacteriaceae, showing that the lipoprotein sorting rules are conserved in these bacteria and validating the use ofE. colias a model system. Although most predicted inner membrane lipoproteins in these bacteria have an aspartate residue after the fatty acylated N-terminal cysteine residue, alternative signals such as CFN can and probably do function in parallel, as indicated by the existence of putative inner membrane lipoproteins with this sequence at their N termini.
Characterization of theYersinia enterocoliticaType III Secretion ATPase YscN and Its Regulator, YscL
Authors: Blaylock Bill , Riordan Kelly E. , Missiakas Dominique M. , Schneewind Olaf 
Published: May 2006

ABSTRACTType III secretion is a mechanism used by a broad range of gram-negative bacteria to neutralize eukaryotic defenses by enabling translocation of bacterial proteins directly into the cytoplasm of host cells. The bacterial energy source for secretion is ATP, which is consumed by an ATPase that couples ATP hydrolysis to the unfolding of secreted proteins and the dissociation of their chaperones just prior to secretion. By studying the biochemical properties of YscN and YscL ofYersinia enterocolitica, we have characterized them as the ATPase and ATPase regulator, respectively, of the type III secretion system of this organism. In vivo, YscL and YscN interact with each other, and the overexpression of glutathioneS-transferase-YscL abolishes secretion and down-regulates the expression of secretion apparatus components.
Identification of a Mutation in the
Bacillus subtilis S
-Adenosylmethionine Synthetase Gene That Results in Derepression of S-Box Gene Expression
Authors: McDaniel Brooke A. , Grundy Frank J. , Kurlekar Vineeta P. , Tomsic Jerneja , Henkin Tina M. 
Published: May 2006

ABSTRACT

Genes in the S-box family are regulated by binding of
S
-adenosylmethionine (SAM) to the 5′ region of the mRNA of the regulated gene. SAM binding was previously shown to promote a rearrangement of the RNA structure that results in premature termination of transcription in vitro and repression of expression of the downstream coding sequence. The S-box RNA element therefore acts as a SAM-binding riboswitch in vitro. In an effort to identify factors other than SAM that could be involved in the S-box regulatory mechanism in vivo, we searched for
trans
-acting mutations in
Bacillus subtilis
that act to disrupt repression of S-box gene expression during growth under conditions where SAM pools are elevated. We identified a single mutant that proved to have one nucleotide substitution in the
metK
gene, encoding SAM synthetase. This mutation, designated
metK10
, resulted in a 15-fold decrease in SAM synthetase activity and a 4-fold decrease in SAM concentration in vivo. The
metK10
mutation specifically affected S-box gene expression, and the increase in expression under repressing conditions was dependent on the presence of a functional transcriptional antiterminator element. The observation that the mutation identified in this search affects SAM production supports the model that the S-box RNAs directly monitor SAM in vivo, without a requirement for additional factors.
d
-Alanyl Ester Depletion of Teichoic Acids in
Lactobacillus plantarum
Results in a Major Modification of Lipoteichoic Acid Composition and Cell Wall Perforations at the Septum Mediated by the Acm2 Autolysin
Authors: Palumbo Emmanuelle , Deghorain Marie , Cocconcelli Pier Sandro , Kleerebezem Michiel , Geyer Armin , Hartung Thomas , Morath Siegfried , Hols Pascal 
Published: May 2006

ABSTRACT

The insertional inactivation of the
dlt
operon from
Lactobacillus plantarum
NCIMB8826 had a strong impact on lipoteichoic acid (LTA) composition, resulting in a major reduction in
d
-alanyl ester content. Unexpectedly, mutant LTA showed high levels of glucosylation and were threefold longer than wild-type LTA. The
dlt
mutation resulted in a reduced growth rate and increased cell lysis during the exponential and stationary growth phases. Microscopy analysis revealed increased cell length, damaged dividing cells, and perforations of the envelope in the septal region. The observed defects in the separation process, cell envelope perforation, and autolysis of the
dlt
mutant could be partially attributed to the
L. plantarum
Acm2 peptidoglycan hydrolase.
Variable Expression Patterns of
Mycobacterium tuberculosis
PE_PGRS Genes: Evidence that PE_PGRS16 and PE_PGRS26 Are Inversely Regulated In Vivo
Authors: Dheenadhayalan Veerabadran , Delogu Giovanni , Sanguinetti Maurizio , Fadda Giovanni , Brennan Michael J. 
Published: May 2006

ABSTRACT

Evaluation of expression of 16 PE_PGRS genes present in
Mycobacterium tuberculosis
under various growth conditions demonstrated constitutive expression of 7 genes, variable expression of 7 genes, and no expression of 2 genes. An inverse expression profile for genes PE_PGRS16 and PE_PGRS26 was observed to occur in macrophages and in mice infected with
M. tuberculosis
. Variable expression of PE_PGRS proteins could have implications for their role in the immunopathogenesis of tuberculosis.
Oxygen exchange between chromium(VI) oxyanions and water
Authors: Holyer R. H. , Baldwin H. W. 
Published: May 2006

The rate of oxygen exchange between O18 enriched CrO42− HCrO4−, Cr2O72− and solvent water has been measured as a function of pH and total chromium(VI) concentration. The exchange can be explained in terms of the dimerization equilibria [Formula: see text] and [Formula: see text] except at high pH, where slow pH-independent exchange is observed. Rate constants for the reactions of the dimerization equilibria have been evaluated from the exchange results, and are in agreement with values obtained by a variety of other methods.