bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of FRIGIDA and FLOWERING LOCUS C in Determining Variation in Flowering Time of Arabidopsis
Authors: Shindo Chikako , Aranzana Maria Jose , Lister Clare , Baxter Catherine , Nicholls Colin , Nordborg Magnus , Dean Caroline 
Published: May 2005

Abstract
Arabidopsis (Arabidopsis thaliana) accessions provide an excellent resource to dissect the molecular basis of adaptation. We have selected 192 Arabidopsis accessions collected to represent worldwide and local variation and analyzed two adaptively important traits, flowering time and vernalization response. There was huge variation in the flowering habit of the different accessions, with no simple relationship to latitude of collection site and considerable diversity occurring within local regions. We explored the contribution to this variation from the two genes FRIGIDA (FRI) and FLOWERING LOCUS C (FLC), previously shown to be important determinants in natural variation of flowering time. A correlation of FLC expression with flowering time and vernalization was observed, but it was not as strong as anticipated due to many late-flowering/vernalization-requiring accessions being associated with low FLC expression and early-flowering accessions with high FLC expression. Sequence analysis of FRI revealed which accessions were likely to carry functional alleles, and, from comparison of flowering time with allelic type, we estimate that approximately 70% of flowering time variation can be accounted for by allelic variation of FRI. The maintenance and propagation of 20 independent nonfunctional FRI haplotypes suggest that the loss-of-function mutations can confer a strong selective advantage. Accessions with a common FRI haplotype were, in some cases, associated with very different FLC levels and wide variation in flowering time, suggesting additional variation at FLC itself or other genes regulating FLC. These data reveal how useful these Arabidopsis accessions will be in dissecting the complex molecular variation that has led to the adaptive phenotypic variation in flowering time.
Two Homologous ATP-Binding Cassette Transporter Proteins, AtMDR1 and AtPGP1, Regulate Arabidopsis Photomorphogenesis and Root Development by Mediating Polar Auxin Transport
Authors: Lin Rongcheng , Wang Haiyang 
Published: May 2005

AbstractLight and auxin control many aspects of plant growth and development in an overlapping manner. We report here functional characterization of two closely related ABC (ATP-binding cassette) transporter genes, AtMDR1 and AtPGP1, in light and auxin responses. We showed that loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation, reduced chlorophyll and anthocyanin accumulation, and abnormal expression of several light-responsive genes, including CAB3, RBCS, CHS, and PORA, under both darkness and far-red light conditions. In addition, we showed that the atmdr1-100 and atmdr1-100/atpgp1-100 mutants are defective in multiple aspects of root development, including increased root-growth sensitivity to 1-naphthalene acetic acid (1-NAA), and decreased sensitivity to naphthylphthalamic acid (NPA)-mediated inhibition of root elongation. Consistent with the proposed role of AtMDR1 in basipetal auxin transport, we found that expression of the auxin responsive DR5::GUS reporter gene in the central elongation zone is significantly reduced in the atmdr1-100 mutant roots treated with 1-NAA at the root tips, compared to similarly treated wild-type plants. Moreover, atmdr1-100, atpgp1-100, and their double mutants produced fewer lateral roots, in the presence or absence of 1-NAA or NPA. The atmdr1-100 and atmdr1-100/atpgp1-100 mutants also displayed enhanced root gravitropism. Genetic-epistasis analysis revealed that mutations in phyA largely suppress the randomized-hypocotyl growth and the short-hypocotyl phenotype of the atmdr1-100 mutants under far-red light, suggesting that phyA acts downstream of AtMDR1. Together, our results suggest that AtMDR1 and AtPGP1 regulate Arabidopsis (Arabidopsis thaliana) photomorphogenesis and multiple aspects of root development by mediating polar auxin transport.
Light-Dark Changes in Cytosolic Nitrate Pools Depend on Nitrate Reductase Activity in Arabidopsis Leaf Cells
Authors: Cookson Sarah J. , Williams Lorraine E. , Miller Anthony J. 
Published: May 2005

Abstract
Several different cellular processes determine the size of the metabolically available nitrate pool in the cytoplasm. These processes include not only ion fluxes across the plasma membrane and tonoplast but also assimilation by the activity of nitrate reductase (NR). In roots, the maintenance of cytosolic nitrate activity during periods of nitrate starvation and resupply (M. van der Leij, S.J. Smith, A.J. Miller [1998] Planta 205: 64–72; R.-G. Zhen, H.-W. Koyro, R.A. Leigh, A.D. Tomos, A.J. Miller [1991] Planta 185: 356–361) suggests that this pool is regulated. Under nitrate-replete conditions vacuolar nitrate is a membrane-bound store that can release nitrate to the cytoplasm; after depletion of cytosolic nitrate, tonoplast transporters would serve to restore this pool. To study the role of assimilation, specifically the activity of NR in regulating the size of the cytosolic nitrate pool, we have compared wild-type and mutant plants. In leaf mesophyll cells, light-to-dark transitions increase cytosolic nitrate activity (1.5–2.8 mm), and these changes were reversed by dark-to-light transitions. Such changes were not observed in nia1nia2 NR-deficient plants indicating that this change in cytosolic nitrate activity was dependent on the presence of functional NR. Furthermore, in the dark, the steady-state cytosolic nitrate activities were not statistically different between the two types of plant, indicating that NR has little role in determining resting levels of nitrate. Epidermal cells of both wild type and NR mutants had cytosolic nitrate activities that were not significantly different from mesophyll cells in the dark and were unaltered by dark-to-light transitions. We propose that the NR-dependent changes in cytosolic nitrate provide a cellular mechanism for the diurnal changes in vacuolar nitrate storage, and the results are discussed in terms of the possible signaling role of cytosolic nitrate.
Patterns of Protein Oxidation in Arabidopsis Seeds and during Germination
Authors: Job Claudette , Rajjou Loïc , Lovigny Yoann , Belghazi Maya , Job Dominique 
Published: May 2005

Abstract
Increased cellular levels of reactive oxygen species are known to occur during seed development and germination, but the consequences in terms of protein degradation are poorly characterized. In this work, protein carbonylation, which is an irreversible oxidation process leading to a loss of function of the modified proteins, has been analyzed by a proteomic approach during the first stages of Arabidopsis (Arabidopsis thaliana) seed germination. In the dry mature seeds, the legumin-type globulins (12S cruciferins) were the major targets. However, the acidic α-cruciferin subunits were carbonylated to a much higher extent than the basic (β) ones, consistent with a model in which the β-subunits are buried within the cruciferin molecules and the α-subunits are more exposed to the outside. During imbibition, various carbonylated proteins accumulated. This oxidation damage was not evenly distributed among seed proteins and targeted specific proteins as glycolytic enzymes, mitochondrial ATP synthase, chloroplastic ribulose bisphosphate carboxylase large chain, aldose reductase, methionine synthase, translation factors, and several molecular chaperones. Although accumulation of carbonylated proteins is usually considered in the context of aging in a variety of model systems, this was clearly not the case for the Arabidopsis seeds since they germinated at a high rate and yielded vigorous plantlets. The results indicate that the observed specific changes in protein carbonylation patterns are probably required for counteracting and/or utilizing the production of reactive oxygen species caused by recovery of metabolic activity in the germinating seeds.
Plantacyanin Plays a Role in Reproduction in Arabidopsis
Authors: Dong Juan , Kim Sun Tae , Lord Elizabeth M. 
Published: May 2005

Abstract
Plantacyanins belong to the phytocyanin family of blue copper proteins. In the Arabidopsis (Arabidopsis thaliana) genome, only one gene encodes plantacyanin. The T-DNA-tagged mutant is a knockdown mutant that shows no visible phenotype. We used both promoter-β-glucuronidase transgenic plants and immunolocalization to show that Arabidopsis plantacyanin is expressed most highly in the inflorescence and, specifically, in the transmitting tract of the pistil. Protein levels show a steep gradient in expression from the stigma into the style and ovary. Overexpression plants were generated using cauliflower mosaic virus 35S, and protein levels in the pistil were examined as well as the pollination process. Seed set in these plants is highly reduced mainly due to a lack of anther dehiscence, which is caused by degeneration of the endothecium. Callose deposits occur on the pollen walls in plants that overexpress plantacyanin, and a small percentage of these pollen grains germinate in the closed anthers. When wild-type pollen was used on the overexpression stigma, seed set was still decreased compared to the control pollinations. We detected an increase in plantacyanin levels in the overexpression pistil, including the transmitting tract. Guidance of the wild-type pollen tube on the overexpression stigma is disrupted as evidenced by the growth behavior of pollen tubes after they penetrate the papillar cell. Normally, pollen tubes travel down the papilla cell and into the style. Wild-type pollen tubes on the overexpression stigma made numerous turns around the papilla cell before growing toward the style. In some rare cases, pollen tubes circled up the papilla cell away from the style and were arrested there. We propose that when plantacyanin levels in the stigma are increased, pollen tube guidance into the style is disrupted.
On understanding seasonal increases in damselfly defence and resistance against ectoparasitic mites
Authors: Robb T. , Forbes M. R. 
Published: May 2005

Abstract.  1. Defence against parasites and pathogens can be essential, yet not all hosts respond similarly to parasitic challenge. Environmental conditions are thought to explain variation in host responses to parasites.2. Lestes forcipatus damselflies emerging later in the season have shown higher resistance to the mite, Arrenurus planus, than hosts emerging earlier. This study was undertaken to determine whether variation in environmental temperatures characteristic of early vs. late emergence times, degree or costs of mite parasitism, and/or size of newly emerged adults could explain seasonal variation in defence and resistance to ectoparasitic mites.3. In this study damselflies from early vs. late emergence groups differed in size at emergence and mite intensity. In general, early hosts were larger and had more mites than later hosts. However only experimental temperatures experienced by damselflies at emergence influenced defence and resistance against mites and not host size or degree of parasitism.4. More specifically, hosts from early and late emergence groups did not differ in defence and resistance when held at the same temperatures in incubators. Housing at a high temperature, indicative of later in the season, was associated with higher defence and resistance for damselflies from both early and late emergence groups.5. These results indicate that daily temperatures in relation to emergence timing can account for seasonal increases in resistance for this temperate insect. Seasonal increases in resistance may be expected for other temperate insect–parasite associations and should have important implications for the phenology of parasites and for seasonal variation in parasite‐mediated selection.
Male field crickets that provide reproductive benefits to females incur higher costs
Authors: Wagner William E. 
Published: May 2005

Abstract.  1. Females often select mates based on signals correlated with the quality of the direct benefits that males will provide to them. A male's quality as a mate and the structure of his mating signals may covary because both traits are energetically expensive for males to produce and because both traits are affected by short‐term changes in nutritional condition.2. In the variable field cricket, Gryllus lineaticeps, previous work has shown that females receive reproductive benefits from males that produce higher chirp rates and lifespan benefits from males that produce longer chirp durations, even when they only receive the sperm and seminal fluid contained in male spermatophores. Higher chirp rates are energetically expensive for males to produce, and chirp rate is strongly affected by diet quality, whereas longer chirp durations do not appear to be expensive for males to produce, and chirp duration does not appear to be affected by male diet quality. In this study two hypotheses were tested about the energetic costs of spermatophore production: (1) that spermatophores are expensive for males to produce and (2) that males providing greater direct benefits to females incur higher costs of spermatophore production.3. Males that were provided with a lower quality diet took longer to produce a new spermatophore. This result suggests that spermatophores are costly for males to produce.4. Males that produced higher chirp rates took longer to produce a new spermatophore. This result suggests that male chirp rate and female reproductive benefits may covary because both traits are energetically expensive for males to produce and thus are affected by male nutritional condition. There was no association, however, between male chirp duration and spermatophore production time.
Mass aerial migration in the carabid beetleNotiophilus biguttatus
Authors: Chapman Jason W. , Reynolds Don R. , Smith Alan D. , Riley Joe R. , Telfer Mark G. , Woiwod Ian P. 
Published: May 2005

Abstract. 1. Catches in traps at 12 and 200 m above ground, and observations with entomological radar, were used to document the high‐altitude windborne movements of carabid beetles over agricultural land in south‐east U.K. during July 1999, 2000, 2002, and 2004.2. Notiophilus biguttatus(Fabricius) was found to be the most abundant species at altitude, with flights by reproductively immature adults resulting in millions of beetles passing through a 1 km2window during the brief migration period in July 2002.3. This result was unexpected in view of the conclusions of an earlier, classic Dutch study by den Boer and colleagues that classifiedN. biguttatusas a poorly dispersing species that tended to become isolated in remnants of natural habitat.4. Reasons for the discrepancy between the two studies are discussed. It is hypothesised that the high mobility seen in theN. biguttatuspopulations results from a recent adaptation of the beetle's migration syndrome allowing it to exploit the mosaic of temporary habitat patches making up the increasingly intensive agroecosystems of northern Europe.
Selection of large host plants for oviposition by a monophagous leaf beetle: nutritional quality or enemy‐free space?
Authors: Heisswolf Annette , Obermaier Elisabeth , Poethke Hans Joachim 
Published: May 2005

Abstract.  1. Oviposition site selection is crucial for the reproductive success of herbivorous insects. According to the preference–performance hypothesis, females should oviposit on host plants that enhance the performance of their offspring. More specifically, the plant vigour hypothesis predicts that females should prefer large and vigorously growing host plants for oviposition and that larvae should perform best on these plants.2. The present study examined whether females of the monophagous leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) prefer to oviposit on large host plant individuals of the meadow clary and whether large host plants are of higher nutritional quality than small host plants. Subsequently, it was tested whether the female preference correlates with offspring performance and survival.3. In the field, females preferred large host plant individuals for oviposition and host plant quality, i.e. leaf nitrogen content, was significantly higher in leaves of large than of small host plants.4. In the laboratory, larval development time was shorter on leaves of large host plant individuals than on small host plant individuals, but this could not be shown in the field.5. However, a predator‐exclusion experiment in the field resulted in a higher survival of larvae on large host plants than on small host plants when all predators had free access to the plants. On caged host plants there was no difference in survival of larvae between plant size categories.6. It is concluded that females of C. canaliculata select oviposition sites that enhance both performance and survival of their offspring, which meets the predictions of the plant vigour hypothesis.
Pharmaceutical promotions and conflict of interest in nurse practitioner's decision making: The undiscovered country
Authors: Crigger Nancy J. 
Published: May 2005

PurposeTo increase nurse practitioners’ (NPs) awareness of the conflict of interest that exists between the NPs’ primary goal of making the best medication choices for patients and the potentially negative impact that the pharmaceutical industry's marketing strategies have on these choices.Data sourcesSelected healthcare professional, philosophical, and bioethical literature was reviewed.ConclusionsHealthcare professionals are given gifts, dinners, and other inducements in the drug industry's effort to increase consumerism and drug sales. The current method of drug promotion increases sales but also increases healthcare expenses. Research also indicates that the pharmaceutical marketing strategies influence the judgments that NPs and other healthcare professionals make about patient care and drug prescriptions.ImplicationsGuidelines are presented that can reduce the likelihood that any conflict of interest that exists will influence NPs’ decisions about patient care.
Tandem practice model: A model for physician‐nurse practitioner collaboration in a specialty practice, neurosurgery
Authors: Herrmann Linda L. , Zabramski Joseph M. 
Published: May 2005

PurposeTo describe the benefits of a physician–nurse practitioner (NP) collaborative practice model, specifically that of a tandem practice model, using a neurosurgeon and a primary care NP in the clinic and inpatient setting.Data sourcesSelected journal articles from Medline and CINAHL, and anecdotal clinical experience.ConclusionsThis collaborative practice model, in which the physician and NP deliver patient care in tandem, is beneficial to patients and their families because they receive comprehensive care that is patient oriented and holistic. Further, the model benefits multiple disciplines across the healthcare continuum by providing efficient communication of patient needs, accessibility of the specialty team, and timely implementation of patient interventions. The collaboration of the physician specialist and primary care NP provides a holistic approach to the care of diverse and challenging patient populations.Implications for practicePatients seen in a specialty practice, particularly that of neurosurgery, often have little understanding of their problem and may be frightened or confused because of their perceptions of the unknown. Providing care to such specialized patient populations in a constantly changing healthcare environment may prove demanding to the specialist. The introduction of a primary care NP into such specialty settings offers patients, their families, consultants, and staff members an additional resource for evaluation, intervention, education, and communication, improving the continuity and comprehensiveness of care to challenging patient populations. This model is an option for physician specialists interested in augmenting their practice and provides further resources for meeting the holistic needs of selected patient populations regardless of the setting.
Relationship of abuse and pelvic inflammatory disease risk behavior in minority adolescents
Authors: Champion Jane Dimmitt , Piper Jeanna M. , Holden Alan E. C. , Shain Rochelle N. , Perdue Sondra , Korte Jeffrey E. 
Published: May 2005

PurposeLittle is known about the relationship between minority adolescent's experiences of sexual or physical abuse and the pathology of gynecological symptoms that might have an impact on the diagnosis of sexually transmitted disease (STD) or risk for pelvic inflammatory disease (PID). The objective of this study was to determine the relationship of sexual or physical abuse to the pathology of genitourinary symptoms that impact diagnoses of STD and risk for PID among Mexican American and African American adolescent women with a current STD.MethodsMexican American and African American adolescent women (n = 373) with an STD underwent a targeted physical exam and questioning regarding sexual or physical abuse, current genitourinary symptomatology, and risk behaviors known to be associated with PID to determine the relationship of sexual or physical abuse to the pathology of genitourinary symptoms that impact diagnoses of STD and risk for PID.ResultsBivariate comparisons found that abused adolescents (n = 232) reported more behaviors associated with increased risk for PID, including earlier coitus, more sex partners, higher STD recurrence, and delayed health‐seeking behavior. Multivariate comparisons found that abused adolescents were more likely to report pathologic genitourinary symptomatology than those who were not abused. Clinicians reported more abnormal physical exams but did not make any more presumptive diagnoses of PID for abused than nonabused adolescents.ConclusionsDelayed treatment for PID dramatically worsens future fertility and chronic pelvic pain. These findings demonstrate that abused adolescent women are at high risk for PID. Because of its considerable impact on risk for PID, an assessment for abuse is essential in clinical management of adolescent women with STD and diagnosis of PID.
Psychosocial predictors of smoking trajectories during middle and high school
Authors: Abroms Lorien , Simons‐Morton Bruce , Haynie Denise L. , Chen Rusan 
Published: May 2005

ABSTRACTAims  Little is known about the heterogeneity in and risk factors associated with trajectories of smoking during adolescence. This study aimed to (1) identify smoking trajectories empirically and (2) identify risk factors for trajectory group membership.Design  Latent growth mixture models were used to identify population smoking trajectories, and logistic regression was used to estimate risk factors for group membership.Setting  The participants were drawn from seven middle schools in a Maryland school district.Participants  Participants consisted of 1320 6th graders who were followed to the 9th grade.Measurements  Measurements of smoking risk factors were made in the fall of 6th grade and smoking stage was assessed on five different occasions between the fall of 6th and 9th grades.Findings  Five distinct smoking trajectories were identified. Overall, being female, having friends who smoked, deviance acceptance and outcome expectations were associated with an increased likelihood of being an intender, delayed escalator, early experimenter and early user compared to a never smoker. Additionally, comparisons with never smokers revealed unique identifiers for intenders, early experimenters and early users, but not delayed escalators.Conclusions  There is much heterogeneity in the manner in which middle‐schoolers progress from having no intention of smoking to becoming smokers. Implications for prevention programs are discussed.