bluuebunny/crossref_metadata_2025 huggingface dataset:
Two Microtubule-Associated Proteins of the Arabidopsis MAP65 Family Function Differently on Microtubules
Authors: Mao Tonglin , Jin Lifeng , Li Hua , Liu Bo , Yuan Ming
Published: May 2005

The organization and dynamics of microtubules are regulated by microtubule-associated proteins, or MAPs. In Arabidopsis (Arabidopsis thaliana), nine genes encode proteins of the evolutionarily conserved MAP65 family. We proposed that different MAP65s might have distinct roles in the interaction with microtubules. In this study, two AtMAP65 proteins, AtMAP65-1 and AtMAP65-6, were chosen to test this hypothesis in vitro. Although both fusion proteins were able to cosediment with microtubules in vitro, different properties on tubulin polymerization and microtubule bundling were observed. AtMAP65-1 was able to promote tubulin polymerization, enhance microtubule nucleation, and decrease the critical concentration for tubulin polymerization. It also induced the formation of large microtubule bundles by forming cross-bridges between microtubules evenly along the whole length of microtubules. In the presence of AtMAP65-1, microtubule bundles were more resistant to cold and dilution treatments. AtMAP65-6, however, demonstrated no activity in promoting tubulin polymerization and stabilizing preformed microtubules. AtMAP65-6 induced microtubules to form a mesh-like network with individual microtubules. Cross-bridge-like interactions were only found at regional sites between microtubules. The microtubule network induced by AtMAP65-6 was more resistant to high concentration of NaCl than the bundles induced by AtMAP65-1. Purified monospecific anti-AtMAP65-6 antibodies revealed that AtMAP65-6 was associated with mitochondria in Arabidopsis cells. It was concluded that these two MAP65 proteins were targeted to distinct sites, thus performing distinct functions in Arabidopsis cells.
Tripeptidyl Peptidase II. An Oligomeric Protease Complex from Arabidopsis
Authors: Book Adam J. , Yang Peizhen , Scalf Mark , Smith Lloyd M. , Vierstra Richard D.
Published: May 2005

The breakdown of most nuclear and cytoplasmic proteins involves their partial cleavage by the 26S proteasome followed by further disassembly to free amino acids by the combined action of endo- and exopeptidases. In animals, one important intermediate exopeptidase is tripeptidyl peptidase (TPP)II, which digests peptide products of the 26S proteasome and other endopeptidases into tripeptides. Here, we describe the purification and characterization of TPPII from Arabidopsis (Arabidopsis thaliana). Like its animal counterparts, Arabidopsis TPPII exists as a soluble, approximately 5- to 9-MD complex. Two related species of 153 and 142 kD are present in the purified preparations that are derived from a single TPP2 gene. Sequencing by Edman degradation of the intact polypeptides and mass spectrometry of proteolytic fragments demonstrated that the 142-kD form mainly differs from the 153-kD form by a truncation at the C-terminal end. This serine protease is a member of the subtilisin superfamily and is sensitive to the inhibitors alanine-alanine-phenylalanine-chloromethylketone and butabindide, which are diagnostic for the TPPII subfamily. The Arabidopsis TPP2 gene is widely expressed in many tissue types with related genes evident in other plant genomes. Whereas the 26S proteasome is essential, TPPII appears not as important for plant physiology. An Arabidopsis T-DNA mutant defective in TPP2 expression displays no phenotypic abnormalities and is not hypersensitive to either amino acid analogs or the 26S proteasome inhibitor MG132. As a consequence, plants likely contain other intermediate exopeptidases that assist in amino acid recycling.
Gene Family Analysis of the Arabidopsis Pollen Transcriptome Reveals Biological Implications for Cell Growth, Division Control, and Gene Expression Regulation
Authors: Pina Cristina , Pinto Francisco , Feijó José A. , Becker Jörg D.
Published: May 2005

Upon germination, pollen forms a tube that elongates dramatically through female tissues to reach and fertilize ovules. While essential for the life cycle of higher plants, the genetic basis underlying most of the process is not well understood. We previously used a combination of flow cytometry sorting of viable hydrated pollen grains and GeneChip array analysis of one-third of the Arabidopsis (Arabidopsis thaliana) genome to define a first overview of the pollen transcriptome. We now extend that study to approximately 80% of the genome of Arabidopsis by using Affymetrix Arabidopsis ATH1 arrays and perform comparative analysis of gene family and gene ontology representation in the transcriptome of pollen and vegetative tissues. Pollen grains have a smaller and overall unique transcriptome (6,587 genes expressed) with greater proportions of selectively expressed (11%) and enriched (26%) genes than any vegetative tissue. Relative gene ontology category representations in pollen and vegetative tissues reveal a functional skew of the pollen transcriptome toward signaling, vesicle transport, and the cytoskeleton, suggestive of a commitment to germination and tube growth. Cell cycle analysis reveals an accumulation of G2/M-associated factors that may play a role in the first mitotic division of the zygote. Despite the relative underrepresentation of transcription-associated transcripts, nonclassical MADS box genes emerge as a class with putative unique roles in pollen. The singularity of gene expression control in mature pollen grains is further highlighted by the apparent absence of small RNA pathway components.
An Expression and Bioinformatics Analysis of the Arabidopsis Serine Carboxypeptidase-Like Gene Family
Authors: Fraser Christopher M. , Rider Lance W. , Chapple Clint
Published: May 2005

The Arabidopsis (Arabidopsis thaliana) genome encodes a family of 51 proteins that are homologous to known serine carboxypeptidases. Based on their sequences, these serine carboxypeptidase-like (SCPL) proteins can be divided into several major clades. The first group consists of 21 proteins which, despite the function implied by their annotation, includes two that have been shown to function as acyltransferases in plant secondary metabolism: sinapoylglucose:malate sinapoyltransferase and sinapoylglucose:choline sinapoyltransferase. A second group comprises 25 SCPL proteins whose biochemical functions have not been clearly defined. Genes encoding representatives from both of these clades can be found in many plants, but have not yet been identified in other phyla. In contrast, the remaining SCPL proteins include five members that are similar to serine carboxypeptidases from a variety of organisms, including fungi and animals. Reverse transcription PCR results suggest that some SCPL genes are expressed in a highly tissue-specific fashion, whereas others are transcribed in a wide range of tissue types. Taken together, these data suggest that the Arabidopsis SCPL gene family encodes a diverse group of enzymes whose functions are likely to extend beyond protein degradation and processing to include activities such as the production of secondary metabolites.
Identification of cis-Elements That Regulate Gene Expression during Initiation of Axillary Bud Outgrowth in Arabidopsis
Authors: Tatematsu Kiyoshi , Ward Sally , Leyser Ottoline , Kamiya Yuji , Nambara Eiji
Published: May 2005

Growth regulation associated with dormancy is an essential element in plant life cycles. To reveal regulatory mechanisms of bud outgrowth, we analyzed transcriptomes of axillary shoots before and after main stem decapitation in Arabidopsis (Arabidopsis thaliana). We searched for any enriched motifs among the upstream regions of up-regulated and down-regulated genes after decapitation. The promoters of down-regulated genes were enriched for TTATCC motifs that resemble the sugar-repressive element, whereas the promoters of up-regulated genes were enriched for GGCCCAWW and AAACCCTA, designated Up1 and Up2, respectively. Transgenic plants harboring a reporter gene driven by a tandem repeat of the elements were produced to analyze their function in vivo. Sugar-repressive element-mediated gene expression was down-regulated by the application of sugars but was unaffected after decapitation. In contrast, expression driven by the repeat containing both Up1 and Up2 was up-regulated after decapitation, although the Up1 or Up2 repeat alone failed to induce reporter gene expression in axillary shoots. In addition, disruption of both Up1 and Up2 elements in a ribosomal protein gene abolished the decapitation-induced expression. Ontological analysis demonstrated that up-regulated genes with Up elements were disproportionately predicted to function in protein synthesis and cell cycle. Up1 is similar to an element known to be a potential target for TCP (TEOSINTE BRANCHED1, CYCLOIDEA, PCFs family) transcription factor(s), which regulate expression of cell cycle-related and ribosomal protein genes. Our data indicate that Up1-mediated transcription of protein synthesis and cell cycle genes is an important regulatory step during the initiation of axillary shoot outgrowth induced by decapitation.
Brassinosteroid Homeostasis in Arabidopsis Is Ensured by Feedback Expressions of Multiple Genes Involved in Its Metabolism
Authors: Tanaka Kiwamu , Asami Tadao , Yoshida Shigeo , Nakamura Yasushi , Matsuo Tomoaki , Okamoto Shigehisa
Published: May 2005

Homeostasis of brassinosteroids (BRs) is essential for normal growth and development in higher plants. We examined responsiveness of 11 BR metabolic gene expressions to the decrease or increase of endogenous BR contents in Arabidopsis (Arabidopsis thaliana) to expand our knowledge of molecular mechanisms underlying BR homeostasis. Five BR-specific biosynthesis genes (DET2, DWF4, CPD, BR6ox1, and ROT3) and two sterol biosynthesis genes (FK and DWF5) were up-regulated in BR-depleted wild-type plants grown under brassinazole, a BR biosynthesis inhibitor. On the other hand, in BR-excessive wild-type plants that were fed with brassinolide, four BR-specific synthesis genes (DWF4, CPD, BR6ox1, and ROT3) and a sterol synthesis gene (DWF7) were down-regulated and a BR inactivation gene (BAS1) was up-regulated. However, their response to fluctuation of BR levels was highly reduced (DWF4) or nullified (the other eight genes) in a bri1 mutant. Taken together, our results imply that BR homeostasis is maintained through feedback expressions of multiple genes, each of which is involved not only in BR-specific biosynthesis and inactivation, but also in sterol biosynthesis. Our results also indicate that their feedback expressions are under the control of a BRI1-mediated signaling pathway. Moreover, a weak response in the mutant suggests that DWF4 alone is likely to be regulated in other way(s) in addition to BRI1 mediation.
New Arabidopsis Recombinant Inbred Lines (Landsberg erecta × Nossen) Reveal Natural Variation in Phytochrome-Mediated Responses
Authors: Magliano Teresa M. Alconada , Botto Javier F. , Godoy A. Veronica , Symonds V. Vaughan , Lloyd Alan M. , Casal Jorge J.
Published: May 2005

We used 52 Arabidopsis (Arabidopsis thaliana) accessions and developed a new set of 137 recombinant inbred lines between Landsberg erecta (Ler) and Nossen (No-0) to explore the genetic basis of phytochrome-mediated responses during deetiolation. Unexpectedly, most accessions showed weak or moderate hypocotyl growth and cotyledon unfolding responses to pulses of far-red light (FR). Crosses between Columbia and No-0, two accessions with poor response, segregated seedlings with unfolded cotyledons under pulsed FR, suggesting the occurrence of accession-specific loci in the repression of morphological responses to weak light signals. Confirming the latter expectation, mapping of responses to pulsed FR in the Ler × No-0 lines identified novel loci. Despite its weak response to pulsed FR, No-0 showed a response to continuous FR stronger than that observed in Ler. By mapping the differential effect of pulsed versus continuous FR, we identified two high-irradiance response loci that account for the steeper response to continuous FR in No-0. This underscores the potential of the methodology to identify loci involved in the regulation of the shape of signal input-output relationships. Loci specific for a given phytochrome-mediated response were more frequent than pleiotropic loci. Segregation of these specific loci is predicted to yield different combinations of seedling responsivity to light. Such flexibility in combination of responses is observed among accessions and could aid in the adjustment to different microenvironments.
Roles of Arabidopsis AtREV1 and AtREV7 in Translesion Synthesis
Authors: Takahashi Shinya , Sakamoto Ayako , Sato Shusei , Kato Tomohiko , Tabata Satoshi , Tanaka Atsushi
Published: May 2005

Plants have mechanisms for repairing and tolerating detrimental effects by various DNA damaging agents. A tolerance pathway that has been predicted to be present in higher plants is translesion synthesis (TLS), which is catalyzed by polymerases. In Arabidopsis (Arabidopsis thaliana), however, the only gene known to be involved in TLS is the Arabidopsis homolog of REV3, AtREV3, which is a putative catalytic subunit of Arabidopsis DNA polymerase ζ. A disrupted mutant of AtREV3, rev3, was previously found to be highly sensitive to ultraviolet-B (UV-B) and various DNA damaging agents. REV1 and REV7 are thought to be components of translesion synthesis in plants. In this study, we identified the Arabidopsis homologs of REV1 and REV7 (AtREV1 and AtREV7). Several mutants carrying disrupted AtREV1 and AtREV7 genes were isolated from Arabidopsis T-DNA-inserted lines. An AtREV1-disrupted mutant, rev1, was found to be moderately sensitive to UV-B and DNA cross-linkers. A rev1rev3 double mutant, like rev3, showed high sensitivity to UV-B, γ-rays, and DNA cross-linkers. An AtREV7-disrupted mutant, rev7, was possibly sensitive to cis-diamminedichloroplatinum(II), a kind of DNA cross-linker, but it was not sensitive to acute UV-B and γ-ray irradiation. On the other hand, the aerial growth of rev7, like the aerial growth of rev1 and rev3, was inhibited by long-term UV-B. These results suggest that a TLS mechanism exists in a higher plant and show that AtREV1 and AtREV7 have important roles in tolerating exposure to DNA-damaging agents.
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

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

Light 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

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

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

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

Purpose

To 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 sources

Selected healthcare professional, philosophical, and bioethical literature was reviewed.

Conclusions

Healthcare 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.

Implications

Guidelines 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

Purpose

To 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 sources

Selected journal articles from Medline and CINAHL, and anecdotal clinical experience.

Conclusions

This 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 practice

Patients 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

Purpose

Little 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.

Methods

Mexican 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.

Results

Bivariate 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.

Conclusions

Delayed 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

Aims  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.
A better widget? Three lessons for improving addiction treatment from a meta‐analytical study
Authors: Berglund Mats
Published: May 2005

Objective  To discuss how to develop more effective treatment programmes than those currently available for addictive disorders.

Data sources  The Swedish SBU report, published in English in 2003, was used as a database. It includes 641 randomized controlled trials and seven longitudinal prospective studies.

Methods  Meta‐analytical calculations were performed in several areas using standardized mean differences (d) effect‐size estimate and homogeneity testing. Three critical issues have been the focus of the present analysis: the early intervention phase, treatment procedures and their additive properties and the transitional period between early and late effects of treatment.

Results  The main findings while integrating the results in a new way were that intervention studies with one single session showed a small but robust homogeneous effect size, whereas studies of interventions with several sessions were heterogeneous with large and small effect sizes among the included studies. Similar effect sizes were found in alcohol, opioid and cocaine treatment studies. Agonist treatment yielded the highest effect sizes. Some evidence was found for a possible additive effect for cognitive behaviour therapy and naltrexone as well as for aversive treatment (disulfiram) and psychosocial treatment in alcohol dependence. So far studies on the transition period between short‐ and long‐term outcome are few and inconclusive.

Conclusions  There is a prospect of improving addiction treatment, and the following areas are suggested by meta‐analysis for future research: (a) to examine in more detail the process between the first and second session of intervention; (b) to randomize simultaneously for independent categories of psychosocial and psychopharmacological treatment; and (c) to intensify studies on the transitional period between short‐ and long‐term outcome.
Cyanobacterial soil crusts and woody shrub canopies in Kalahari rangelands
Authors: Berkeley A. , Thomas A. D. , Dougill A. J.
Published: May 2005

Intensive grazing of Kalahari rangelands has led to woody plant encroachment, notably of Acacia mellifera and Grewia flava. The mechanisms causing this process, and the ecological stability of woody plant encroached ecosystems, remain uncertain. Past studies suggest that canopy–soil relations may enhance woody plant competitive dominance. This study aims to investigate one element of this ecological change by examining the spatial distribution of cyanobacterial soil crusts in two vegetation sub‐habitats at sites of different disturbance. Crust burial by litter was also assessed to analyse the dynamics of canopy–crust relations. Our results show there is enhanced cyanobacterial crust cover under A. mellifera canopies and that unlike G. flava canopies, the crust cover remains under A. mellifera even at highly disturbed sites. This canopy–crust association suggests A. mellifera encroachment exhibits intrinsic resilience because of the crusts ability to stabilize the soil surface and increase nutrient retention. Crust burial by litter that accumulates under larger woody plants restricts crust development under canopies. Disturbance restricts crust development in plant interspaces and under G. flava. These two mechanisms combine to restrict crust development to an observed 40% threshold, with nonlinear models required to explain spatial patterns of crust dynamics.
First laboratory confirmation of Xylophilus ampelinus in Slovenia*
Authors: Dreo T. , Seljak G. , Janse J. D. , Van Der Beld I. , Tjou‐Tam‐Sin L. , Gorkink‐Smits P. , Ravnikar M.
Published: May 2005

Bacterial blight of grapevine is caused by a slow‐growing bacterium Xylophilus ampelinus. It has been suspected to occur in Slovenia on the basis of visual observation of characteristic symptoms in the 1960s. In the present study, symptoms were recorded in an infected vineyard during three consecutive years (2002/2004). Samples from this vineyard were tested by nested‐PCR and isolation of bacteria on media was attempted. In the first year, angular lesions on leaves were highly expressed and an isolate morphologically similar to X. ampelinus was obtained from one sample. It was purified and identified as X. ampelinus using biochemical and nutritional tests, fatty acid analysis, immuno‐fluorescence, nested PCR and partial sequencing of the 16S rRNA gene. The 16S rDNA sequence showed 99–100% homology to known sequences of X. ampelinus strains, including the type strain. Pathogenicity of the isolate was confirmed in tissue‐cultured and potted grapevine plants. In the following two years, symptoms of bacterial blight were only faintly expressed. Using isolation on media and nested‐PCR, 23 and 17 extracts prepared from 10 and 8 grapevines, respectively, were analysed. In 2003, no positive sample was found, but X. ampelinus was again isolated and identified by colony morphology and nested‐PCR in 2004.
Reliability of nucleic acid amplification techniques: modified target RNA as exogenous internal standard for a real‐time RT‐PCR for Potato spindle tuber pospiviroid*
Authors: Kox L. F. F. , Boxman I. L. A. , Jansen C. C. C. , Roenhorst J. W.
Published: May 2005

Techniques based on nucleic acid amplification techniques, like PCR, are quick, sensitive and specific, and therefore very suitable for the development of diagnostic tests. These techniques enable the detection of very small amounts of target organisms by specific amplification of part of its genome. This exquisite sensitivity puts a high demand on measures to prevent false‐positive reactions due to contamination of the laboratory with nucleic acid, hence the need for inclusion of negative controls. In addition, to exclude false negatives, the performance of the reactions must be measured by the inclusion of several positive controls, e.g. cytochrome oxidase (COX) primers (and probes) to monitor efficiency of the nucleic acid extraction and an internal control to monitor inhibition of the target PCR. For the RT‐PCR assay for Potato spindle tuber pospiviroid (PSTVd) recently described by Boonham and coworkers, we have developed an exogenous internal standard, i.e. in vitro RNA transcribed from a plasmid containing a modified PSTVd sequence (a 17‐bp sequence of cloned PSTVd (isolate Howell) was substituted for a 118‐bp sequence of Escherichia coli). To this exogenous sequence, a specific probe was designed with a fluorescent label different from that of the PSTVd‐specific probe. By making use of the same primers as the target organism PSTVd, this internal standard provides a tool to measure the performance of the specific reaction. Moreover, by using another fluorescent probe, this standard can easily be discriminated from the target organism. The approach used for the construction of the internal control for PSTVd offers a tool for the construction of internal standards for other pathogens.
Official diagnosis of pests in Germany: recent activities to secure the quality of diagnostic work*
Authors: Pfeilstetter E.
Published: May 2005

Within the federal organization of Germany, the practical implementation of phytosanitary legislation including diagnosis of pests is the task of the Plant Protection Services of the 16 Federal Länder. The Federal Biological Research Centre (BBA) gives support by developing diagnostic methods, advising and in some instances reference testing. Due to budgetary constraints during the past decade, there has been a considerable decrease in diagnostic and taxonomic capacities. An analysis of the status quo of the diagnostic abilities in relation to regulated pests, and new pests not yet present in Germany, was carried out by means of a questionnaire sent to the Plant Protection Services of the Länder and to the various institutes of the BBA. The data gathered by the questionnaire supports the need for maintaining and improving diagnostic capacities in Germany, in order to fulfil legal obligations and to cope with evolving challenges, e.g. in the field of quality assurance. In this respect, a future scenario could be the establishment of a diagnostic network within Germany. Some key elements of such a network are already implemented in the potato sector.
Dipteran leafminers in the vicinity of glasshouses and plant markets in Lithuania*
Authors: Ostrauskas H. , Pakalniškis S. , Taluntytė L.
Published: May 2005

Areas surrounding the glasshouses of 60 growers, and 16 plant markets, were surveyed in 2001/2003 to determine the distribution of dipterous leafminers in Lithuania, including regulated species. In total, 152 species belonging to 7 families were discovered, and the infested host plants represented 46 families. The relative frequency of Liriomyza bryoniae was 32% in the vicinity of glasshouses and 19% in market places. This species attacked plant genera such as: Amaranthus, Beta, Bryonia, Chenopodium, Cucumis, Datura, Gypsophila, Lycopersicon, Nicandra, Nicotiana, Physalis, Petunia, Sisymbrium, Solanum, Spinacia and Viola. The same plant genera also potentially provide sites for the survival of economically important species, Liriomyza huidobrensis and Liriomyza trifolii, in Lithuania.
Molecular characterization of a morphologically unusual potato cyst nematode*
Authors: Reid A. , Pickup J.
Published: May 2005

During routine screening of soil samples for potato cyst nematodes, a morphologically variant cyst was detected. The internal transcribed spacer regions of the ribosomal DNA repeat unit from individual juveniles hatched from the cyst were amplified by PCR. The resulting products were digested with a range of restriction enzymes and their RFLP profiles compared with standard samples of Globodera rostochiensis and Globodera pallida. Most of the RFLP profiles yielded patterns similar to those of G. pallida although some restriction enzymes gave hybrid patterns showing elements of both G. rostochiensis and G. pallida. Clones of individual ITS regions from a single nematode from the variant cyst displayed either a G. pallida or G. rostochiensis pattern.