bluuebunny/crossref_metadata_2025 huggingface dataset:
Seismic expression of shallow structures in active tectonic settings in New Zealand
Authors: Cape C.D. , O'Connor R.M. , Ravens J.M. , Woodward D.J.
Published: November 2007

Late Cenozoic deformation along the Australian/Pacific plate boundary is seen in onshore New Zealand as zones characterised by extension- or transcurrent- or contraction-related structures. High-resolution multichannel seismic reflection data were acquired in several of these tectonic zones and successfully reveal the shallow structures within them. Thirty kilometres of dynamite reflection data in the Rangitaiki Plains, eastern Bay of Plenty, define a series of NE-trending normal faults within this extensional back-arc volcanic region. The data cross surface ruptures activated during the 1987 Edgecumbe earthquake. In the southern North Island, a 20 km Mini-Sosie? seismic profile details the Quaternary sedimentation history and reveals the structure of the active strike-slip and thrust fault systems that form the western and eastern edges of the Wairarapa basin, respectively. This basin is considered to sit astride the boundary between a zone of distributed strike-slip faults and an active accretionary prism. In the Nelson area, northwestern South Island, previously unrecognised low-angle thrust faults of Neogene or Quaternary age are seen from Mini-Sosie data to occur at very shallow depths. Crustal shortening here was previously thought to arise from movement on high-angle reverse faults, and the identification of these low-angle faults has prompted a reassessment of that model. A grid of 18 km of Mini-Sosie seismic data from the central eastern South Island delineates Neogene or Quaternary thrust faults in Cenozoic sediments. The thrusts are interpreted as reactivated Early Eocene normal faults, and the thrust fault geometry is dominated by these older structures.
Offset VSP's ? examples of their application to exploration in the Timor Sea
Authors: King G.M. , Endersby S.
Published: November 2007

BHP Petroleum has acquired seven Offset Vertical Seismic Profiles (OVSP's) since commencing exploration in the Timor Sea and all were acquired with the aim of defining more accurately the position of a bounding fault close to the well. OVSP's were acquired at Montara-1 and Bilyara-1 to assist in planning proposed sidetracks. In both of these cases there were significant differences between the fault location determined from the OVSP and the fault position interpreted on the seismic data. The discrepancies were in excess of 100 m in both cases and show that migrated 2D data do not have the accuracy that we sometimes assume. A comparison of two OVSP images using different receiver spacings (10 m and 20 m) showed that there was a significant improvement in resolution and clarity of the image when using the 10 m spacing. The OVSP's acquired at Montara-1 and Bilyara-1 provided a more accurate image of the subsurface close to the well bore and therefore were useful in planning options such as sidetracking the wells.
A regional seismic synthesis of the offshore Gippsland Basin
Authors: Maung T.U.
Published: November 2007

Structure contour maps compiled and synthesised from interpretive company data for top of Strzelecki Group/Basement, intra-Latrobe Group, and top of Latrobe Group seismic horizons give an indication of the formation and evolution of the Gippsland Basin during Early Cretaceous, and Late Cretaceous to Tertiary tectonic events. Comparison of the intra- and top of Latrobe Group mapping illustrates a change from a largely extensional to a compressive tectonic regime during the Eocene.
The application of a joint MT CSAMT survey to oil exploration
Authors: Hastie L.M. , Cevallos C. , Chant I.J.
Published: November 2007

A survey was carried out over the Tallyabra anticline in the Eromanga Basin Queensland, using both controlled source and passive magnetotelluric techniques to investigate the structure in the top 2 km. The results from the controlled source system were very encouraging and, using the resistivity log from the well Kenmore 7 as a control, the top of the oil bearing Hutton Sandstone was resolved at a depth of about 1400 m. The magnetotelluric results were consistent with those from the controlled source, but the data accuracy was so much lower that in these circumstances they added little information.
Factors affecting the management of cattle grazing distribution in northern Australia: preliminary observations on the effect of paddock size and water points
Authors: Hunt L. P. , Petty S. , Cowley R. , Fisher A. , Ash A. J. , MacDonald N.
Published: November 2007

Achieving more uniform grazing at landscape and paddock scales is seen as an important management objective by pastoralists in northern Australia, but it is difficult to attain in practice. This paper presents a brief review of some key factors to be considered in attempts to modify grazing distribution in extensive rangelands by drawing on the preliminary results of a project that is investigating several options for achieving more uniform grazing. Subdividing the landscape into smaller paddocks and, to a lesser extent, installing additional water points in large paddocks are effective in distributing grazing more widely across the landscape. However, these approaches are less effective in achieving uniform grazing within paddocks, and areas of concentrated use still occur even in small paddocks. To achieve spatial grazing objectives, it is necessary to use management tools that operate at the appropriate scale. Attaining more even use within paddocks should therefore be viewed as a separate management objective, requiring different techniques, to obtaining more effective use of the landscape as a whole. Integrating the use of several spatial management tools that act at different scales is likely to be most effective in improving grazing distribution. Our findings also highlight the importance of understanding paddocks in terms of the spatial arrangement of forage resources and their acceptability and quality in relation to water points and other landscape features. Differences between individual cattle in the way they use the landscape are important in producing more uniform use in larger paddocks and may also offer other opportunities for improving the use of landscape resources overall. Finally, the implications of more uniform use for livestock production and other land use values should be considered, with the protection of biodiversity values potentially requiring special management arrangements where more even use is achieved.
Does Geijera parviflora Lindl. (Rutaceae) facilitate understorey species in semi-arid Australia?
Authors: Warnock A. D. , Westbrooke M. E. , Florentine S. K. , Hurst C. P.
Published: November 2007

Species composition under tree canopies often differs from that of surrounding micro-environments. In arid and semi-arid zones, trees can be beneficial to understorey vegetation. This study examined zones of vegetation composition and soil physiochemical parameters associated with Geijera parviflora Lindl. The importance of shade, rainfall redistribution, seed bank and soil moisture were examined. Species abundance, soil moisture, seed bank composition, rainfall redistribution and soil nutrient concentration were measured under five randomly selected mature G. parviflora trees in south-western New South Wales, Australia. To complement the findings from this study, artificial shade plots were constructed in a canopy-free area and species abundance measured seven months after shade construction. The study demonstrated that G. parviflora was associated with zonation of understorey vegetation. Two zones of understorey vegetation were found in relation to G. parviflora: (i) under the tree canopy with high species diversity, and (ii) beyond the canopy, this community being dominated by Dissocarpus paradoxus throughout the year with Crassula colorata appearing after rainfall. The zone beyond the canopy also had lower soil nutrient concentrations. Soil moisture, nutrient concentration and the seed bank density were significantly higher under the canopy. However, the canopy reduced precipitation reaching the soil surface. The effects of the canopy on understorey species composition and soil moisture were enhanced after winter rainfall. Artificial shade increased species abundance and richness under a 90%-shading treatment. The results indicated that G. parviflora generated spatial heterogeneity over the broader plant community increasing species richness, abundance and diversity under the canopy. This emphasises the importance of arid zone trees in conserving understorey plant diversity. Shading, soil nutrient concentration and increased seed bank density and soil moisture appeared to be key influences on the plant communities under the canopy.
Sleep transforms the cerebral trace of declarative memories
Authors: Gais Steffen , Albouy Geneviève , Boly Mélanie , Dang-Vu Thien Thanh , Darsaud Annabelle , Desseilles Martin , Rauchs Géraldine , Schabus Manuel , Sterpenich Virginie , Vandewalle Gilles , Maquet Pierre , Peigneux Philippe
Published: November 2007

After encoding, memory traces are initially fragile and have to be reinforced to become permanent. The initial steps of this process occur at a cellular level within minutes or hours. Besides this rapid synaptic consolidation, systems consolidation occurs within a time frame of days to years. For declarative memory, the latter is presumed to rely on an interaction between different brain regions, in particular the hippocampus and the medial prefrontal cortex (mPFC). Specifically, sleep has been proposed to provide a setting that supports such systems consolidation processes, leading to a transfer and perhaps transformation of memories. Using functional MRI, we show that postlearning sleep enhances hippocampal responses during recall of word pairs 48 h after learning, indicating intrahippocampal memory processing during sleep. At the same time, sleep induces a memory-related functional connectivity between the hippocampus and the mPFC. Six months after learning, memories activated the mPFC more strongly when they were encoded before sleep, showing that sleep leads to long-lasting changes in the representation of memories on a systems level.
Two closely related RecQ helicases have antagonistic roles in homologous recombination and DNA repair in
Arabidopsis thaliana
Authors: Hartung Frank , Suer Stefanie , Puchta Holger
Published: November 2007

RecQ helicases are involved in the processing of DNA structures arising during replication, recombination, and repair throughout all kingdoms of life. Mutations of different RecQ homologues are responsible for severe human diseases, such as Blooms (BLM) or Werner (WRN) syndrome. The loss of RecQ function is often accompanied by hyperrecombination caused by a lack of crossover suppression. In the Arabidopsis genome seven different RecQ genes are present. Two of them (At
RECQ4A
and
4B
) arose because of a recent duplication and are still nearly 70% identical on a protein level. Knockout of these genes leads to antagonistic phenotypes: the
RECQ4A
mutant shows sensitivity to DNA-damaging agents, enhanced homologous recombination (HR) and lethality in a
mus81
background. Moreover, mutation of
RECQ4A
partially suppresses the lethal phenotype of an At
TOP3
α mutant, a phenomenon that had previously been demonstrated for RecQ homologues of unicellular eukaryotes only. Together, these facts strongly suggest that in plants RECQ4A is functionally equivalent to SGS1 of
Saccharomyces cerevisiae
and the mammalian BLM protein. In stark contrast, mutants of the closely related
RECQ4B
are not mutagen-sensitive, not viable in a
mus81
background, and unable to suppress the induced lethality caused by loss of
TOP3
α. Moreover, they are strongly impaired in HR. Thus, AtRECQ4B is specifically required to promote but not to suppress crossovers, a role in which it differs from all eukaryotic RecQ homologues known.
Mental Health Care for our Ageing Australian Population
Authors: Hassett Anne , Fortune Tracy , Smith Brad
Published: November 2007

Objective: In the context of the National Strategy for an Ageing Australia, the aim of this paper was to highlight some of the challenges for aged mental health services as our population ages.

Conclusions: The demand for greater consumer participation in treatment planning and provision, and the increasing complexity of managing medical and psychiatric comorbidity in our ‘old-old’ population will be major drivers for improving our models of clinical practice and forging stronger partnerships between the public and private sectors.
Qualified therapists’ experience of personal therapy
Authors: Daw Becky , Joseph Stephen
Published: November 2007

Recent work shows that the majority of therapists strongly value personal therapy for what it can bring to their professional practice, and for personal development. The aim of this study was to explore qualified therapists’ experiences of personal therapy. Of the 220 qualified therapists who were contacted via post and asked to take part in a questionnaire study, 48 returned the completed questionnaire, which consisted of a series of closed and open questions. Two‐thirds of respondents had engaged in personal therapy. The two most frequently cited reasons for engaging in personal therapy were personal growth and personal distress. Interpretative phenomenological analysis (IPA) identified two broad domains: impact on the person and impact on the professional. Results show that those surveyed recognised the value of personal therapy to themselves as a form of self‐care and personal development. Personal therapy was valued in professional practice as a form of experiential learning from being in the client role. The limitations of this research included a relatively low response rate, raising the question of whether those most likely to have had positive experiences of personal therapy were more likely to participate. Future research might deliberately seek to understand negative experiences of personal therapy. Other avenues for future research include the need to understand how experiences of therapy relate to gender, profession, and therapeutic orientation.
Introducing humanistic group counselling for somatisation in a primary care practice: Preliminary findings
Authors: Graham J. , Manor O. , Wiseman S.
Published: November 2007

Can group counselling help patients who present with symptoms that cannot be explained medically? Preliminary results of working with one such group are reported. Six patients in a primary care practice were offered weekly sessions for half a year. The findings suggest that the patients attended all group sessions. The patients reported experiences known to be related to group counselling, and when the group ended, patient reports show that the severity of their problems was reduced significantly (p<.001). Furthermore, during the six months after the group ended patients significantly (p<.025) reduced their visits to their general practitioners. These results seem to call for wider use of humanistic group counselling with somatising patients and further research into the impact of such form of counselling.
Single session and walk‐in psychotherapy: A descriptive account of the literature
Authors: Cameron Christopher L.
Published: November 2007

Over the last several decades single session psychotherapy has become a mainstream psychotherapeutic approach. A steadily increasing demand for psychotherapeutic services and a continuous reduction in mental health care resources worldwide are both largely responsible for this development. This paper describes single session psychotherapy and provides a brief review of the relevant literature. Single session psychotherapy delivered in walk‐in settings is also discussed. Therapists who are unfamiliar with single session psychotherapy will find that this paper provides a concise introduction to the essential processes and outcomes of this psychotherapeutic approach.
Assessment of measurement uncertainty via observation equations
Authors: Possolo Antonio , Toman Blaza
Published: November 2007

According to theGuide to the Expression of Uncertainty in Measurement(GUM) (1995, Geneva, Switzerland: International Organization for Standardization (ISO)), the uncertainty in an estimate of the value of a measurand is assessed by propagating the uncertainty in estimates of values of input quantities, based on ameasurement equationthat expresses the former value as a known function of the latter values. However, in measurement situations where some of the input quantities in turn depend on the measurand, this approach is circuitous and ultimately impracticable.

An alternative approach starts from theobservation equation, which relates the experimental data to the measurand: this allows a uniform treatment of the most diverse metrological problems, and, once it is used in the context of Bayesian inference, also facilitates the exploitation of any information that may pre-exist about the measurand, alongside the information that fresh experimental data provide about it.

The widest applicability of the observation equation approach is illustrated with detailed examples concerning the lifetime of mechanical parts, the measurement of mass, the calibration of a non-linear model in biochemistry and the estimation of a consensus value for arsenic concentration in a sample measured by multiple laboratories.
Topography and Crop Management Are Key Factors for the Development of American Leaf Spot Epidemics on Coffee in Costa Rica
Authors: Avelino Jacques , Cabut Sandrine , Barboza Bernardo , Barquero Miguel , Alfaro Ronny , Esquivel César , Durand Jean-François , Cilas Christian
Published: November 2007

We monitored the development of American leaf spot of coffee, a disease caused by the gemmiferous fungus Mycena citricolor, in 57 plots in Costa Rica for 1 or 2 years in order to gain a clearer understanding of conditions conducive to the disease and improve its control. During the investigation, characteristics of the coffee trees, crop management, and the environment were recorded. For the analyses, we used partial least-squares regression via the spline functions (PLSS), which is a nonlinear extension to partial least-squares regression (PLS). The fungus developed well in areas located between ≈1,100 and 1,550 m above sea level. Slopes were conducive to its development, but eastern-facing slopes were less affected than the others, probably because they were more exposed to sunlight, especially in the rainy season. The distance between planting rows, the shade percentage, coffee tree height, the type of shade, and the pruning system explained disease intensity due to their effects on coffee tree shading and, possibly, on the humidity conditions in the plot. Forest trees and fruit trees intercropped with coffee provided particularly propitious conditions. Apparently, fertilization was unfavorable for the disease, probably due to dilution phenomena associated with faster coffee tree growth. Finally, series of wet spells interspersed with dry spells, which were frequent in the middle of the rainy season, were critical for the disease, probably because they affected the production and release of gemmae and their viability. These results could be used to draw up a map of epidemic risks taking topographical factors into account. To reduce those risks and improve chemical control, our results suggested that farmers should space planting rows further apart, maintain light shading in the plantation, and prune their coffee trees.
Evaluation of the Genetic Diversity ofXylella fastidiosaStrains from Citrus and Coffee Hosts by Single-Nucleotide Polymorphism Markers
Authors: Wickert Ester , Machado Marcos Antonio , Lemos Eliana G. M.
Published: November 2007

The aim of this study was to obtain information about genetic diversity and make some inferences about the relationship of 27 strains of Xylella fastidiosa from different hosts and distinct geographical areas. Single-nucleotide polymorphism (SNP) molecular markers were identified in DNA sequences from 16 distinct regions of the genome of 24 strains of X. fastidiosa from coffee and citrus plants. Among the Brazilian strains, coffee-dependent strains have a greater number of SNPs (10 to 24 SNPs) than the citrus-based strains (2 to 12 SNPs); all the strains were compared with the sequenced strain 9a5c. The identified SNP markers were able to distinguish, for the first time, strains from citrus plants and coffee and showed that strains from coffee present higher genetic diversity than the others. These markers also have proven to be efficient for discriminating strains from the same host obtained from different geographic regions. X. fastidiosa, the causal agent of citrus variegated chlorosis, possesses genetic diversity, and the SNP markers were highly efficient for discriminating genetically close organisms.
Black Pod: Diverse Pathogens with a Global Impact on Cocoa Yield
Authors: Guest David
Published: November 2007

Pathogens of the Straminipile genus Phytophthora cause significant disease losses to global cocoa production. P. megakarya causes significant pod rot and losses due to canker in West Africa, whereas P. capsici and P. citrophthora cause pod rots in Central and South America. The global and highly damaging P. palmivora attacks all parts of the cocoa tree at all stages of the growing cycle. This pathogen causes 20 to 30% pod losses through black pod rot, and kills up to 10% of trees annually through stem cankers. P. palmivora has a complex disease cycle involving several sources of primary inoculum and several modes of dissemination of secondary inoculum. This results in explosive epidemics during favorable environmental conditions. The spread of regional pathogens must be prevented by effective quarantine barriers. Resistance to all these Phytophthora species is typically low in commercial cocoa genotypes. Disease losses can be reduced through integrated management practices that include pruning and shade management, leaf mulching, regular and complete harvesting, sanitation and pod case disposal, appropriate fertilizer application and targeted fungicide use. Packaging these options to improve uptake by smallholders presents a major challenge for the industry.
Development of a Marker Assisted Selection Program for Cacao
Authors: Schnell R. J. , Kuhn D. N. , Brown J. S. , Olano C. T. , Phillips-Mora W. , Amores F. M. , Motamayor J. C.
Published: November 2007

Production of cacao in tropical America has been severely affected by fungal pathogens causing diseases known as witches' broom (WB, caused by Moniliophthora perniciosa), frosty pod (FP, caused by M. roreri) and black pod (BP, caused by Phytophthora spp.). BP is pan-tropical and causes losses in all producing areas. WB is found in South America and parts of the Caribbean, while FP is found in Central America and parts of South America. Together, these diseases were responsible for over 700 million US dollars in losses in 2001 (4). Commercial cacao production in West Africa and South Asia are not yet affected by WB and FP, but cacao grown in these regions is susceptible to both. With the goal of providing new disease resistant cultivars the USDA-ARS and Mars, Inc. have developed a marker assisted selection (MAS) program. Quantitative trait loci have been identified for resistance to WB, FP, and BP. The potential usefulness of these markers in identifying resistant individuals has been confirmed in an experimental F1 family in Ecuador.
Coloration using higher order optical interference in the wing pattern of the Madagascan sunset moth
Authors: Yoshioka S , Nakano T , Nozue Y , Kinoshita S
Published: November 2007

Colour patterns of animals' bodies are usually produced by the spatial distribution of pigments with different colours. However, some animals use the spatial variation of colour-producing microstructures. We have studied one distinctive example of such structurally produced colour patterns, the wing of the Madagascan sunset moth, to clarify the physical rules that underlie the colour variation. It is known that the iridescent wing scale of the sunset moth has the alternate air–cuticle multilayer structure that causes optical interference. The microscopic and optical investigations of various parts of the wing have confirmed that the thickness of the cuticle layers within the scale largely varies to produce the colour pattern. However, it varies in very different ways between the dorsal and ventral sides of the hind wing; the thickness gradually varies on the dorsal side from scale to scale, while the abrupt changes are found on the ventral side to form distinctive borders between differently coloured areas. It is also revealed that an unusual coloration mechanism is involved in the green part of the ventral hind wing: the colour is caused by higher order optical interference of the highly non-ideal multilayer structure. The physical mechanism of the colour pattern formation is briefly discussed with the several mathematical models proposed so far.
The completeness of taxonomic inventories for describing the global diversity and distribution of marine fishes
Authors: Mora Camilo , Tittensor Derek P , Myers Ransom A
Published: November 2007

Taxonomic inventories (or species censuses) are the most elementary data in biogeography, macroecology and conservation biology. They play fundamental roles in the construction of species richness patterns, delineation of species ranges, quantification of extinction risk and prioritization of conservation efforts in hot spot areas. Given their importance, any issue related to the completeness of taxonomic inventories can have far-reaching consequences. Here, we used the largest publicly available database of georeferenced marine fish records to determine its usefulness in depicting the diversity and distribution of this taxonomic group. All records were grouped at multiple spatial resolutions to generate accumulation curves, from which the expected number of species were extrapolated using a variety of nonlinear models. Comparison of the inventoried number of species with that expected from the models was used to calculate the completeness of the taxonomic inventory at each resolution. In terms of the global number of fish species, we found that approximately 21% of the species remain to be described. In terms of spatial distribution, we found that the completeness of taxonomic data was highly scale dependent, with completeness being lower at finer spatial resolutions. At a 3° (approx. 350 km
2
) spatial resolution, less than 1.8% of the world's oceans have above 80% of their fish fauna currently described. Censuses of species were particularly incomplete in tropical areas and across the entire range of countries' gross domestic product (GDP), although the few censuses nearing completion were all along the coasts of a few developed countries or territories. Our findings highlight that failure to quantify the completeness of taxonomic inventories can introduce substantial flaws in the description of diversity patterns, and raise concerns over the effectiveness of conservation strategies based upon data that remain largely precarious.
A Bifunctional Locus (BIO3-BIO1) Required for Biotin Biosynthesis in Arabidopsis
Authors: Muralla Rosanna , Chen Elve , Sweeney Colleen , Gray Jennifer A. , Dickerman Allan , Nikolau Basil J. , Meinke David
Published: November 2007

We identify here the Arabidopsis (Arabidopsis thaliana) gene encoding the third enzyme in the biotin biosynthetic pathway, dethiobiotin synthetase (BIO3; At5g57600). This gene is positioned immediately upstream of BIO1, which is known to be associated with the second reaction in the pathway. Reverse genetic analysis demonstrates that bio3 insertion mutants have a similar phenotype to the bio1 and bio2 auxotrophs identified using forward genetic screens for arrested embryos rescued on enriched nutrient medium. Unexpectedly, bio3 and bio1 mutants define a single genetic complementation group. Reverse transcription-polymerase chain reaction analysis demonstrates that separate BIO3 and BIO1 transcripts and two different types of chimeric BIO3-BIO1 transcripts are produced. Consistent with genetic data, one of the fused transcripts is monocistronic and encodes a bifunctional fusion protein. A splice variant is bicistronic, with distinct but overlapping reading frames. The dual functionality of the monocistronic transcript was confirmed by complementing the orthologous auxotrophs of Escherichia coli (bioD and bioA). BIO3-BIO1 transcripts from other plants provide further evidence for differential splicing, existence of a fusion protein, and localization of both enzymatic reactions to mitochondria. In contrast to most biosynthetic enzymes in eukaryotes, which are encoded by genes dispersed throughout the genome, biotin biosynthesis in Arabidopsis provides an intriguing example of a bifunctional locus that catalyzes two sequential reactions in the same metabolic pathway. This complex locus exhibits several unusual features that distinguish it from biotin operons in bacteria and from other genes known to encode bifunctional enzymes in plants.
Diarch Symmetry of the Vascular Bundle in Arabidopsis Root Encompasses the Pericycle and Is Reflected in Distich Lateral Root Initiation
Authors: Parizot Boris , Laplaze Laurent , Ricaud Lilian , Boucheron-Dubuisson Elodie , Bayle Vincent , Bonke Martin , De Smet Ive , Poethig Scott R. , Helariutta Yka , Haseloff Jim , Chriqui Dominique , Beeckman Tom , Nussaume Laurent
Published: November 2007

The outer tissues of dicotyledonous plant roots (i.e. epidermis, cortex, and endodermis) are clearly organized in distinct concentric layers in contrast to the diarch to polyarch vascular tissues of the central stele. Up to now, the outermost layer of the stele, the pericycle, has always been regarded, in accordance with the outer tissue layers, as one uniform concentric layer. However, considering its lateral root-forming competence, the pericycle is composed of two different cell types, with one subset of cells being associated with the xylem, showing strong competence to initiate cell division, whereas another group of cells, associated with the phloem, appears to remain quiescent. Here, we established, using detailed microscopy and specific Arabidopsis thaliana reporter lines, the existence of two distinct pericycle cell types. Analysis of two enhancer trap reporter lines further suggests that the specification between these two subsets takes place early during development, in relation with the determination of the vascular tissues. A genetic screen resulted in the isolation of mutants perturbed in pericycle differentiation. Detailed phenotypical analyses of two of these mutants, combined with observations made in known vascular mutants, revealed an intimate correlation between vascular organization, pericycle fate, and lateral root initiation potency, and illustrated the independence of pericycle differentiation and lateral root initiation from protoxylem differentiation. Taken together, our data show that the pericycle is a heterogeneous cell layer with two groups of cells set up in the root meristem by the same genetic pathway controlling the diarch organization of the vasculature.
Involvement of Polyamine Oxidase in Wound Healing
Authors: Angelini Riccardo , Tisi Alessandra , Rea Giuseppina , Chen Martha M. , Botta Maurizio , Federico Rodolfo , Cona Alessandra
Published: November 2007

Hydrogen peroxide (H2O2) is involved in plant defense responses that follow mechanical damage, such as those that occur during herbivore or insect attacks, as well as pathogen attack. H2O2 accumulation is induced during wound healing processes as well as by treatment with the wound signal jasmonic acid. Plant polyamine oxidases (PAOs) are H2O2 producing enzymes supposedly involved in cell wall differentiation processes and defense responses. Maize (Zea mays) PAO (ZmPAO) is a developmentally regulated flavoprotein abundant in primary and secondary cell walls of several tissues. In this study, we investigated the effect of wounding on ZmPAO gene expression in the outer tissues of the maize mesocotyl and provide evidence that ZmPAO enzyme activity, protein, and mRNA levels increased in response to wounding as well as jasmonic acid treatment. Histochemically detected ZmPAO activity especially intensified in the epidermis and in the wound periderm, suggesting a tissue-specific involvement of ZmPAO in wound healing. The role played by ZmPAO-derived H2O2 production in peroxidase-mediated wall stiffening events was further investigated by exploiting the in vivo use of N-prenylagmatine (G3), a selective and powerful ZmPAO inhibitor, representing a reliable diagnostic tool in discriminating ZmPAO-mediated H2O2 production from that generated by peroxidase, oxalate oxidase, or by NADPH oxidase activity. Here, we demonstrate that G3 inhibits wound-induced H2O2 production and strongly reduces lignin and suberin polyphenolic domain deposition along the wound, while it is ineffective in inhibiting the deposition of suberin aliphatic domain. Moreover, ZmPAO ectopic expression in the cell wall of transgenic tobacco (Nicotiana tabacum) plants strongly enhanced lignosuberization along the wound periderm, providing evidence for a causal relationship between PAO and peroxidase-mediated events during wound healing.
The Catalytic Properties of Hybrid Rubisco Comprising Tobacco Small and Sunflower Large Subunits Mirror the Kinetically Equivalent Source Rubiscos and Can Support Tobacco Growth
Authors: Sharwood Robert Edward , von Caemmerer Susanne , Maliga Pal , Whitney Spencer Michael
Published: November 2007

Plastomic replacement of the tobacco (Nicotiana tabacum) Rubisco large subunit gene (rbcL) with that from sunflower (Helianthus annuus; rbcLS) produced tobaccoRst transformants that produced a hybrid Rubisco consisting of sunflower large and tobacco small subunits (LsSt). The tobaccoRst plants required CO2 (0.5% v/v) supplementation to grow autotrophically from seed despite the substrate saturated carboxylation rate, K  m, for CO2 and CO2/O2 selectivity of the LsSt enzyme mirroring the kinetically equivalent tobacco and sunflower Rubiscos. Consequently, at the onset of exponential growth when the source strength and leaf LsSt content were sufficient, tobaccoRst plants grew to maturity without CO2 supplementation. When grown under a high pCO2, the tobaccoRst seedlings grew slower than tobacco and exhibited unique growth phenotypes: Juvenile plants formed clusters of 10 to 20 structurally simple oblanceolate leaves, developed multiple apical meristems, and the mature leaves displayed marginal curling and dimpling. Depending on developmental stage, the LsSt content in tobaccoRst leaves was 4- to 7-fold less than tobacco, and gas exchange coupled with chlorophyll fluorescence showed that at 2 mbar pCO2 and growth illumination CO2 assimilation in mature tobaccoRst leaves remained limited by Rubisco activity and its rate (approximately 11 μmol m−2 s−1) was half that of tobacco controls. 35S-methionine labeling showed the stability of assembled LsSt was similar to tobacco Rubisco and measurements of light transient CO2 assimilation rates showed LsSt was adequately regulated by tobacco Rubisco activase. We conclude limitations to tobaccoRst growth primarily stem from reduced rbcLS mRNA levels and the translation and/or assembly of sunflower large with the tobacco small subunits that restricted LsSt synthesis.
A Genomic and Expression Compendium of the ExpandedPEBPGene Family from Maize
Authors: Danilevskaya Olga N. , Meng Xin , Hou Zhenglin , Ananiev Evgueni V. , Simmons Carl R.
Published: November 2007

The phosphatidylethanolamine-binding proteins (PEBPs) represent an ancient protein family found across the biosphere. In animals they are known to act as kinase and serine protease inhibitors controlling cell growth and differentiation. In plants the most extensively studied PEBP genes, the Arabidopsis (Arabidopsis thaliana) FLOWERING LOCUS T (FT) and TERMINAL FLOWER1 (TFL1) genes, function, respectively, as a promoter and a repressor of the floral transition. Twenty-five maize (Zea mays) genes that encode PEBP-like proteins, likely the entire gene family, were identified and named Zea mays CENTRORADIALIS (ZCN), after the first described plant PEBP gene from Antirrhinum. The maize family is expanded relative to eudicots (typically six to eight genes) and rice (Oryza sativa; 19 genes). Genomic structures, map locations, and syntenous relationships with rice were determined for 24 of the maize ZCN genes. Phylogenetic analysis assigned the maize ZCN proteins to three major subfamilies: TFL1-like (six members), MOTHER OF FT AND TFL1-like (three), and FT-like (15). Expression analysis demonstrated transcription for at least 21 ZCN genes, many with developmentally specific patterns and some having alternatively spliced transcripts. Expression patterns and protein structural analysis identified maize candidates likely having conserved gene function of TFL1. Expression patterns and interaction of the ZCN8 protein with the floral activator DLF1 in the yeast (Saccharomyces cerevisiae) two-hybrid assay strongly supports that ZCN8 plays an orthologous FT function in maize. The expression of other ZCN genes in roots, kernels, and flowers implies their involvement in diverse developmental processes.
Compound Leaf Development and Evolution in the Legumes
Authors: Champagne Connie E.M. , Goliber Thomas E. , Wojciechowski Martin F. , Mei Raymond W. , Townsley Brad T. , Wang Kan , Paz Margie M. , Geeta R. , Sinha Neelima R.
Published: November 2007

Across vascular plants, Class 1 KNOTTED1-like (KNOX1) genes appear to play a critical role in the development of compound leaves. An exception to this trend is found in the Fabaceae, where pea (Pisum sativum) uses UNIFOLIATA, an ortholog of the floral regulators FLORICAULA (FLO) and LEAFY (LFY), in place of KNOX1 genes to regulate compound leaf development. To assess the phylogenetic distribution of KNOX1-independent compound leaf development, a survey of KNOX1 protein expression across the Fabaceae was undertaken. The majority of compound-leafed Fabaceae have expression of KNOX1 proteins associated with developing compound leaves. However, in a large subclade of the Fabaceae, the inverted repeat–lacking clade (IRLC), of which pea is a member, KNOX1 expression is not associated with compound leaves. These data suggest that the FLO/LFY gene may function in place of KNOX1 genes in generating compound leaves throughout the IRLC. The contribution of FLO/LFY to leaf complexity in a member of the Fabaceae outside of the IRLC was examined by reducing expression of FLO/LFY orthologs in transgenic soybean (Glycine max). Transgenic plants with reduced FLO/LFY expression showed only slight reductions in leaflet number. Overexpression of a KNOX1 gene in alfalfa (Medicago sativa), a member of the IRLC, resulted in an increase in leaflet number. This implies that KNOX1 targets, which promote compound leaf development, are present in alfalfa and are still sensitive to KNOX1 regulation. These data suggest that KNOX1 genes and the FLO/LFY gene may have played partially overlapping roles in compound leaf development in ancestral Fabaceae but that the FLO/LFY gene took over this role in the IRLC.
Riboswitch Control of Gene Expression in Plants by Splicing and Alternative 3′ End Processing of mRNAs
Authors: Wachter Andreas , Tunc-Ozdemir Meral , Grove Beth C. , Green Pamela J. , Shintani David K. , Breaker Ronald R.
Published: November 2007

The most widespread riboswitch class, found in organisms from all three domains of life, is responsive to the vitamin B1 derivative thiamin pyrophosphate (TPP). We have established that a TPP-sensing riboswitch is present in the 3′ untranslated region (UTR) of the thiamin biosynthetic gene THIC of all plant species examined. The THIC TPP riboswitch controls the formation of transcripts with alternative 3′ UTR lengths, which affect mRNA accumulation and protein production. We demonstrate that riboswitch-mediated regulation of alternative 3′ end processing is critical for TPP-dependent feedback control of THIC expression. Our data reveal a mechanism whereby metabolite-dependent alteration of RNA folding controls splicing and alternative 3′ end processing of mRNAs. These findings highlight the importance of metabolite sensing by riboswitches in plants and further reveal the significance of alternative 3′ end processing as a mechanism of gene control in eukaryotes.
Saturated Very-Long-Chain Fatty Acids Promote Cotton Fiber and Arabidopsis Cell Elongation by Activating Ethylene Biosynthesis
Authors: Qin Yong-Mei , Hu Chun-Yang , Pang Yu , Kastaniotis Alexander J. , Hiltunen J. Kalervo , Zhu Yu-Xian
Published: November 2007

Fatty acids are essential for membrane biosynthesis in all organisms and serve as signaling molecules in many animals. Here, we found that saturated very-long-chain fatty acids (VLCFAs; C20:0 to C30:0) exogenously applied in ovule culture medium significantly promoted cotton (Gossypium hirsutum) fiber cell elongation, whereas acetochlor (2-chloro-N-[ethoxymethyl]-N-[2-ethyl-6-methyl-phenyl]-acetamide; ACE), which inhibits VLCFA biosynthesis, abolished fiber growth. This inhibition was overcome by lignoceric acid (C24:0). Elongating fibers contained significantly higher amounts of VLCFAs than those of wild-type or fuzzless-lintless mutant ovules. Ethylene nullified inhibition by ACE, whereas C24:0 was inactive in the presence of the ethylene biosynthesis inhibitor (l-[2-aminoethoxyvinyl]-glycine), indicating that VLCFAs may act upstream of ethylene. C24:0 induced a rapid and significant increase in ACO (for 1-aminocyclopropane-1-carboxylic acid oxidase) transcript levels that resulted in substantial ethylene production. C24:0 also promoted Ser palmitoyltransferase expression at a later stage, resulting in increased sphingolipid biosynthesis. Application of C24:0 not only stimulated Arabidopsis thaliana root cell growth but also complemented the cut1 phenotype. Transgenic expression of Gh KCS13/CER6, encoding the cotton 3-ketoacyl-CoA synthase, in the cut1 background produced similar results. Promotion of Arabidopsis stem elongation was accompanied by increased ACO transcript levels. Thus, VLCFAs may be involved in maximizing the extensibility of cotton fibers and multiple Arabidopsis cell types, possibly by activating ethylene biosynthesis.
ARGONAUTE4 Is Required for Resistance toPseudomonas syringaeinArabidopsis
Authors: Agorio Astrid , Vera Pablo
Published: November 2007

Here, we report the characterization of the Arabidopsis thaliana ocp11 (for overexpressor of cationic peroxidase11) mutant, in which a β-glucuronidase reporter gene under the control of the H2O2-responsive Ep5C promoter is constitutively expressed. ocp11 plants show enhanced disease susceptibility to the virulent bacterium Pseudomonas syringae pv tomato DC3000 (P.s.t. DC3000) and also to the avirulent P.s.t. DC3000 carrying the effector avrRpm1 gene. In addition, ocp11 plants are also compromised in resistance to the nonhost pathogen P. syringae pv tabaci. Genetic and molecular analyses reveal that ocp11 plants are not affected in salicylic acid perception. We cloned OCP11 and show that it encodes ARGONAUTE4 (AGO4), a component of the pathway that mediates the transcriptional gene silencing associated with small interfering RNAs that direct DNA methylation at specific loci, a phenomenon known as RNA-directed DNA methylation (RdDM). Thus, we renamed our ocp11 mutant ago4-2, as it represents a different allele to the previously characterized recessive ago4-1. Both mutants decrease the extent of DNA cytosine methylation at CpNpG and CpHpH (asymmetric) positions present at different DNA loci and show commonalities in all of the molecular and phenotypic aspects that we have considered. Interestingly, we show that AGO4 works independently of other components of the RdDM pathway in mediating resistance to P.s.t. DC3000, and loss of function in other components of the pathway operating upstream of AGO4, such as RDR2 and DCL3, or operating downstream, such as DRD1, CMT3, DRM1, and DRM2, does not compromise resistance to this pathogen.
Arabidopsis FIERY1, XRN2, and XRN3 Are Endogenous RNA Silencing Suppressors
Authors: Gy Isabelle , Gasciolli Virginie , Lauressergues Dominique , Morel Jean-Benoit , Gombert Julie , Proux Florence , Proux Caroline , Vaucheret Hervé , Mallory Allison C.
Published: November 2007

The eukaryotic defense response posttranscriptional gene silencing (PTGS) is directed by short-interfering RNAs and thwarts invading nucleic acids via the RNA slicing activity of conserved ARGONAUTE (AGO) proteins. PTGS can be counteracted by exogenous or endogenous suppressors, including the cytoplasmic exoribonuclease XRN4, which also degrades microRNA (miRNA)-guided mRNA cleavage products but does not play an obvious role in development. Here, we show that the nuclear exoribonucleases XRN2 and XRN3 are endogenous PTGS suppressors. We also identify excised MIRNA loops as templates for XRN2 and XRN3 and show that XRN3 is critical for proper development. Independently, we identified the nucleotidase/phosphatase FIERY1 (FRY1) as an endogenous PTGS suppressor through a suppressor screen in a hypomorphic ago1 genetic background. FRY1 is one of six Arabidopsis thaliana orthologs of yeast Hal2. Yeast hal2 mutants overaccumulate 3′-phosphoadenosine 5′-phosphate, which suppresses the 5′→3′ exoribonucleases Xrn1 and Rat1. fry1 mutant plants recapitulate developmental and molecular characteristics of xrn mutants and likely restore PTGS in ago1 hypomorphic mutants by corepressing XRN2, XRN3, and XRN4, thus increasing RNA silencing triggers. We anticipate that screens incorporating partially compromised silencing components will uncover additional PTGS suppressors that may not be revealed using robust silencing systems.
Measuring the effectiveness of managerial action in SMEs
Authors: Metts Glenn A.
Published: November 2007

Purpose

The paper's purpose is to investigate the direct and indirect effects of industry competitive forces on strategy‐making and performance in small‐to‐medium‐sized manufacturing companies.

Design/methodology/approach

The paper's approach is a survey design with structural equation modeling used for hypotheses testing.

Findings

The findings provide strong support for the mitigating role of managerial action through the strategy‐making process and indications that this is true regardless of small‐to‐medium‐sized enterprise (SME) size. Also, automotive‐manufacturing SMEs seem to exhibit higher levels of competitive factors compared with non‐automotive manufacturing SMEs.

Research limitations/implications

The major limitation of this research is that the survey was taken in the Mid‐western USA and involved only SME manufacturing organizations. The research should be extended to other geographic regions, industry types, and larger organizations.

Practical implications

Many small company managers feel that they have little impact on industry‐wide macro‐economic and industry‐specific forces. This research indicates that managers in SMEs can mitigate some of the negative effects of industry competitive factors through strategy‐making activities.

Originality/value

This research is unique in several ways. It is the only research that has clearly identified and successfully measured the impact of managerial action in SMEs. It demonstrates that managerial action can be measured by comparing the direct and indirect effects of industry competitive forces on performance. It further identifies the need for a self‐assessment tool to measure the effectiveness of managerial action of top managers in SMEs.