bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of daily increment formation in otoliths of juvenile and adult European anchovy
Authors: Cermeño P. , Uriarte A. , De Murguía A. M. , Morales‐Nin B.
Published: December 2003

The otoliths of juveniles and adults of European anchovy Engraulis encrasicolus held in aquaria were marked by immersion in oxytetracycline hydrochloride (OTC) at concentrations between 350 and 410 mg l−1 for 12 h. Counts of microincrements between fluorescent bands validated the daily otolith increment formation. The otolith increments were easily readable at ×400 with average increment widths of c. 1·1 µm. Validation was successfully demonstrated in juveniles and adults maintained for short periods in the aquaria in the summer. For European anchovy captured as juvenile and reared to adults, however, increment formation appeared less than daily. The daily periodicity of the otoliths in juvenile European anchovy implies that counting of microincrements can be used to study their birth dates. The application of this technique to adults, however, may lead to the underestimation of actual age and further research needs to be done to clarify the reasons for the apparent loss of the daily rhythm over long periods.
Scaling of rectal gland mass in the European lesser‐spotted dogfish
Authors: Anderson W. G. , Good J. P. , Franklin C. E. , Hazon N.
Published: December 2003

In the European lesser‐spotted dogfish Scyliorhinus canicula, rectal gland mass in mg (MRg) followed the allometric relationship: MRg = 1·15M0·68, where M is body mass (g). The concept of allometric scaling is an important consideration in studies investigating the function of osmoregulatory organs.
Predation by brown trout: a major mortality factor for sexually mature European minnows
Authors: Museth J. , BorgstrØm R. , Hame T. , Holen L. Å.
Published: December 2003

Brown trout Salmo trutta in the subalpine lake, Øvre Heimdalsvatn, showed large temporal variation in the rate of predation on the introduced minnow Phoxinus phoxinus population. Minnows were found in the stomachs of brown trout between 16 and 38 cm LT. Significantly greater predation was recorded shortly after ice break at the end of June 1999, with frequencies of 9 and 20% within the LT classes 16–29·9 cm and  ≥30 cm, respectively. Predation on minnows was only occasionally detected during July, August and September. The high level of predation coincided with minnow spawning, and lengths of consumed minnows were equal to those of sexually mature individuals. Accepting a causal link between minnow spawning, which lasted c. 3 weeks, and the contemporary high rate of predation, the estimated annual consumption of minnows by the brown trout population would be 138 kg wet mass. Although most of the annual consumption of minnows by brown trout (90%) occurred within a very short period (3 weeks), it accounted for a significant proportion (60%) of the annual loss in biomass of the sexually mature part of the population.
Variability in condition and growth of Atlantic cod larvae and juveniles reared in mesocosms: environmental and maternal effects
Authors: Clemmesen C. , Bühler V. , Carvalho G. , Case R. , Evans G. , Hauser L. , Hutchinson W. F. , Kjesbu O. S. , Mempel H. , Moksness E. , Otteraa H. , Paulsen H. , Thorsen A. , Svaasand T.
Published: December 2003

Standard length, dry mass and RNA : DNA ratio measurements of 3876 Atlantic cod Gadus morhua larvae and juveniles from 26 families of recruit (fish during their first year of spawning) and repeat spawners (fish which were in their subsequent spawning season) reared in two mesocosms (2500 and 4400 m3) under semi‐natural conditions were analysed over a period of 10 weeks using microsatellites. Larvae from recruit spawners were significantly longer and heavier at hatch and throughout the 10 weeks. RNA : DNA ratios from recruit spawner offspring were only significantly higher at week 1. The smaller (2500 m3) mesocosm was characterized by low plankton density during the transition from endogenous to exogenous feeding followed by a higher density during the metamorphosis period (weeks 4 and 5), with the reverse pattern evident in the 4400 m3 mesocosm. Patterns of larval growth followed patterns of zooplankton density. Significant differences in RNA : DNA ratios between the mesocosms at all comparable sampling dates were found and within each mesocosm individual fish exhibited a wide range of growth and condition responses under the same environmental conditions. RNA : DNA ratios as a function of size differed in the amount of variability between mesocosms, indicating that the higher food density led to a higher proportion of well‐conditioned larvae in the first 3 weeks. Food availability probably has a major role in determining offspring growth and condition, with limited effects due to maternal effects in cases where the broodstock females are approximately of similar size and condition.
A morphometric method for estimation of total lipid level in live Arctic charr: a case study of its application on wild fish
Authors: Rikardsen A. H. , Johansen M.
Published: December 2003

Linear body measurements were made on wild Arctic charr Salvelinus alpinus parr (100–200 mm LF) from two populations in northern Norway during spring (May), summer (June and July) and autumn (October). To reduce handling stress, a method was developed were dorsal and ventral body measurements could subsequently be taken easily from a single picture of the anaesthetized fish. Multiple regression analyses investigated the possible correlation between the body measurements and both total and percentage lipid content of the fish. For both populations and during all seasons, the regression equations gave better estimates for total lipid than for percentage lipid. The regression equations for total lipid accounted for between 67·7 and 89·5% of the variance in lipid content for the different seasons within the lakes. The pooled data within each lake accounted for 62·9 and 81·0% of the variance in total lipid, while the pooled data for both lakes accounted for 67·7% of the variance. In general, the condition factor alone did not give a satisfactory estimate of lipid content of the Arctic charr (r2 = 0·003–0·521). Shrinkage on validation values was high (0·20–0·52). Employing a ridge regression method resulted in models with lower r2 values and lower shrinkage values (indicating more stable models). Published equations used for hatchery‐reared Arctic charr could not be used on wild fish from the same population. The close correlations between actual and predicted lipid levels found in this study show that morphometric measurements can predict total lipid levels in wild Arctic charr with reasonable accuracy. The most accurate results were obtained when equations were derived from each data set. Therefore, the method has the potential within a single study to estimate lipid levels in live fish as long as some fish can be sacrificed to develop a unique regression equation for each population or experiment.
Paternal postpartum depression, its relationship to maternal postpartum depression, and implications for family health
Authors: Goodman Janice H.
Published: December 2003

Background. Much attention has been paid to the problem of postpartum depression in women. However, there is some indication that men also experience depression after the birth of a child, and that paternal depression is linked to maternal depression.

Aims. The purpose of this integrative review was to examine current knowledge about postpartum depression in fathers. Specific aims were (1) to examine the incidence of paternal depression in the first year after the birth of a child, (2) to identify the characteristics and predictors of paternal postpartum depression, (3) to describe the relationship between maternal and paternal postpartum depression, and (4) to discuss the influence of paternal depression on the family and infant.

Methods. A literature search from 1980 to 2002 was carried out using the CINAHL, PsychInfo, and Medline electronic databases. Twenty research studies were identified that included incidence rates of paternal depression during the first year postpartum. These were further examined and synthesized regarding onset, severity, duration, and predictors of paternal depressive symptoms, and for information about the relationship between maternal and paternal depression.

Findings. During the first postpartum year, the incidence of paternal depression ranged from 1·2% to 25·5% in community samples, and from 24% to 50% among men whose partners were experiencing postpartum depression. Maternal depression was identified as the strongest predictor of paternal depression during the postpartum period. The implications of parental depression for family health were discussed.

Conclusions. Postpartum depression in men is a significant problem. The strong correlation of paternal postpartum depression with maternal postpartum depression has important implications for family health and well‐being. Consideration of postpartum depression in fathers as well as mothers, and consideration of co‐occurrence of depression in couples, is an important next step in research and practice involving childbearing families.
Technology‐dependent children and their families: a review
Authors: Wang Kai‐Wei Katherine , Barnard Alan
Published: December 2003

Background.  Advances in medical technology and nursing care have enabled children who rely on long‐term medical and technical support to reunite with their families and community. The impact of discharging these children into the community involves a number of unprecedented social implications that warrant policy consideration. To begin with, an effort must be made to understand the phenomenon of caring for technology‐dependent children living at home.

Aim.  The aim of this paper is to provide a comprehensive literature review on caring for technology‐dependent children living at home.

Methods.  The review was conducted via keyword searches using various electronic databases. These included CINAHL, MEDLINE, Social Science Index, Sociological Abstracts, Australian Family and Society Abstracts, and the Australian Bureau of Statistics. The articles and books found were examined for commonality and difference, significant themes were extracted, and the strength of the research methods and subsequent evidence were critiqued.

Findings.  In this paper, themes relating to home care for technology‐dependent children and their families are elucidated and summarized. These are: chronic illness and children; the impact of paediatric home care on children; the uniqueness of technology‐dependent children and their families; and parents’ experience of paediatric home care.

Discussion.  Contentious issues, relevant to the social life of these children and their families, are raised and are discussed with the intention of extending awareness and provoking further debate among key stakeholders. These issues include: the changed meaning of home; family dynamics; social isolation; saving costs for whom?; shifts in responsibility; and parent–professional relationships.

Conclusion.  More research is needed in the arena of paediatric home care, to facilitate relevant policy formation and implementation.
Decision‐making in clinical nursing: investigating contributing factors
Authors: Hoffman Kerry , Donoghue Judith , Duffield Christine
Published: December 2003

Background.  This article describes the results of a study which investigated the contextual factors influencing clinical decision‐making. Education and experience have been suggested by some as having a positive effect on clinical decision‐making, and have been listed as being of high importance. Values, knowledge, clinical setting and stress have also been identified as being important to decision‐making, with various rankings given by different researchers.

Aim.  The study was undertaken to determine relationships between occupational orientation (value to role), educational level, experience, area of practice, level of appointment, age and clinical decision‐making in Australian nurses. The predictive ability of each factor on clinical decision‐making was determined.

Method.  This correlational study examined Australian nurses’ decision‐making about some common nursing interventions and ‘occupational orientation’, educational level, experience, level of appointment, area of clinical speciality and age. A model was constructed using stepwise selection regression to predict the ‘weight’ of each variable in clinical decision‐making.

Results.  Education and experience were not significantly related to decision‐making. The factor that accounted for the greatest variability to clinical decision‐making was holding a professional occupational orientation, followed by level of appointment, area of clinical speciality, and age in that order.

Conclusion.  In contrast to other studies, experience and educational level were not found to influence decision‐making strongly, the value of role was the most significant predictor. The model developed, however, only accounted for a low amount of variability in decision‐making. The findings indicate that there are other factors affecting clinical decision‐making that still require identification.
Quality of life of clients with schizophrenia
Authors: Chan Sally , Yu Iu Wai
Published: December 2003

Background.  Because of the deinstitutionalization of mental health care in Hong Kong that has taken place since the 1980s, many people with mental health problems are being cared for in the community. The majority of clients have a diagnosis of schizophrenia, and many have a long duration of illness and multiple readmissions. There is concern about their quality of life.

Aim.  To investigate quality of life and related factors in clients with a diagnosis of schizophrenia in Hong Kong.

Design.  A convenience sample was recruited from a psychiatric outpatient department. Structured face‐to‐face interviews were conducted using the Brief Psychiatric Rating Scale and the Hong Kong Chinese World Health Organization Quality of Life Scale‐Brief Version.

Results.  A total of 172 people participated in the study. Most of them were single and unemployed. They were least satisfied with their psychological health, financial situation, life enjoyment and sexual activity. Women (n = 91) reported less satisfaction with quality of life than men (n = 86). Unemployed people (n = 100) were less satisfied with their quality of life than the employed (n = 76). Higher levels of mental health problems and higher numbers of previous hospitalizations were associated with negative perceptions of quality of life.

Discussion.  People with mental health problems had significantly less satisfaction with their quality of life than a sample from the general population in Hong Kong surveyed in a previous study. As well as experiencing distressing mental symptoms, they had many difficulties, such as financial problems, unemployment and lack of opportunities to participate in social activities, that resulted from stigma and discrimination. These had a great impact on their quality of life.

Study limitations.  Because of the small sample size and its convenience nature, the findings may not be generalizable to all clients in Hong Kong. A generic instrument was used to measure quality of life, and this may not have been sensitive to certain aspects of mental health clients’ lives.

Conclusion.  The findings suggest that there is a need to strengthen social and vocational rehabilitation for people with mental health problems in Hong Kong. A more holistic and intensive model of care is required to meet their complex needs. A larger and more diverse sample should be used in future research, and a quality of life measure specifically designed for people with mental health problems should be used.
Revising the Critical Care Family Needs Inventory for the Emergency Department
Authors: Redley Bernice , Beanland Christine
Published: December 2003

Background.  The Critical Care Family Needs Inventory (CCFNI) has been used widely over the last two decades for analysing the needs of family members in the intensive care unit. However, it has significant limitations as a needs assessment tool for use with families in the Emergency Department (ED). This paper discusses the methodological challenges encountered during the process of reviewing and adapting this tool for use in the ED.

Aims.  The purpose of this study was to revise and adapt the CCFNI for use with a population of family members of critically ill patients in an Australian Emergency Department.

Instrument.  The process of tool revision, adaptation and reconstruction included: critique of the CCFNI; concept definition; item review; content and structure revision; scale revision; and testing with a sample of the target population.

Methods.  Data collection methods were aimed at accessing a vulnerable population, while enhancing response rate and data quality. A sample of 84 relatives of critically ill patients from one Melbourne Metropolitan Emergency Department was used, 73% of whom returned questionnaires.

Results.  Pilot data were examined with the specific purpose of identifying elements of the tool that required refinement or modification. Methods used for establishing reliability and validity of the revised tool provided satisfactory results.

Limitations.  Limitations of this study include inadequate sample size for exploratory factor analysis, and an incomplete response set for some items, which influenced item analysis.

Conclusion.  The process used for addressing the identified methodological issues in reviewing and adapting the CCFNI for use in the ED provides a framework for adapting an established tool for a specific purpose.
Potato virus Y NIa protease activity is not sufficient for elicitation of Ry‐mediated disease resistance in potato
Authors: Mestre Pere , Brigneti Gianinna , Durrant Marcus C. , Baulcombe David C.
Published: December 2003

Ry confers extreme resistance (ER) to all strains of potato virus Y (PVY). In previous work, we have shown that the protease domain of the nuclear inclusion a protease (NIaPro) from PVY is the elicitor of the Ry‐mediated resistance and that integrity of the protease active site is required for the elicitation of the resistance response. Two possibilities arise from these results: first, the structure of the active protease has elicitor activity; second, NIa‐mediated proteolysis is required to elicit the resistance response. To resolve these possibilities, the NIaPro from PVY was randomly mutagenised and the clones obtained were screened for elicitation of cell death as an indicator of resistance and proteolytic activity. We did not find any mutants that had retained the ability to elicit cell death but had lost protease activity, as measured by processing of the NIa cleavage site in the viral genome. This was consistent with the idea that protease activity is necessary for elicitor activity. However, protease activity was not sufficient because we found three elicitor‐defective mutants in which there was a high level of protease activity in this assay.
Anionic lipids are required for chloroplast structure and function in Arabidopsis
Authors: Yu Bin , Benning Christoph
Published: December 2003

Photosynthetic membranes of plants primarily contain non‐phosphorous glycolipids. The exception is phosphatidylglycerol (PG), which is an acidic/anionic phospholipid. A second major anionic lipid in chloroplasts is the sulfolipid sulfoquinovosyldiacylglycerol (SQDG). It is hypothesized that under severe phosphate limitation, SQDG substitutes for PG, ensuring a constant proportion of anionic lipids even under adverse conditions. A newly constructed SQDG and PG‐deficient double mutant supports this hypothesis. This mutant, sqd2 pgp1‐1, carries a T‐DNA insertion in the structural gene for SQDG synthase (SQD2) and a point mutation in the structural gene for phosphatidylglycerolphosphate synthase (PGP1). In the sqd2 pgp1‐1 double mutant, the fraction of total anionic lipids is reduced by approximately one‐third, resulting in pale yellow cotyledons and leaves with reduced chlorophyll content. Photoautotrophic growth of the double mutant is severely compromised, and its photosynthetic capacity is impaired. In particular, photosynthetic electron transfer at the level of photosystem II (PSII) is affected. Besides these physiological changes, the mutant shows altered leaf structure, a reduced number of mesophyll cells, and ultrastructural changes of the chloroplasts. All observations on the sqd2 pgp1‐1 mutant lead to the conclusion that the total content of anionic thylakoid lipids is limiting for chloroplast structure and function, and is critical for overall photoautotrophic growth and plant development.
Synthesis of ketocarotenoids in the seed of Arabidopsis thaliana
Authors: Stålberg Kjell , Lindgren Ove , Ek Bo , Höglund Anna‐Stina
Published: December 2003

A cDNA coding for a gene necessary for synthesis of ketocarotenoids was cloned from the alga Haematococcus pluvialis and expressed in the seed of Arabidopsis thaliana. The expression of the algal β‐carotene‐oxygenase gene was directed to the seed by use of the 2S, seed storage protein promoter napA. Extracts from seeds of the transgenic plants were clearly red because of accumulation of ketocarotenoids, and free and esterified forms of ketocarotenoids were found in addition to the normal carotenoid composition in the seed. The major ketocarotenoids in the transgenic plants were: 4‐keto‐lutein (3,3′‐dihydroxy‐β‐,ε‐carotene‐4‐one), adonirubin (3‐hydroxy‐β‐,β′‐carotene‐4,4′‐dione) and canthaxanthin (β‐,β′‐carotene‐4,4′‐dione). 4‐Keto‐lutein differs from the more common adonixanthin only in the position of one double bond. To increase the substrate availability for the β‐carotene‐oxygenase, these transformants were crossed with transgenic plants overexpressing a construct of an endogenous phytoene synthase gene, also under the control of the napA promoter. The resulting crossings gave rise to seeds with a 4.6‐fold relative increase of the total pigment, and the three major ketocarotenoids were increased 13‐fold compared to seeds of transgenic plants carrying only the β‐carotene‐oxygenase construct.
Antisense LOX expression increases herbivore performance by decreasing defense responses and inhibiting growth‐related transcriptional reorganization in Nicotiana attenuata
Authors: Halitschke Rayko , Baldwin Ian T.
Published: December 2003

Inhibition of jasmonic acid (JA) signaling has been shown to decrease herbivore resistance, but the responsible mechanisms are largely unknown because insect resistance is poorly understood in most model plant systems. We characterize three members of the lipoxygenase (LOX) gene family in the native tobacco plant Nicotiana attenuata and manipulate, by antisense expression, a specific, wound‐ and herbivory‐induced isoform (LOX3) involved in JA biosynthesis. In three independent lines, antisense expression reduced wound‐induced JA accumulation but not the release of green leaf volatiles (GLVs). The impaired JA signaling reduced two herbivore‐induced direct defenses, nicotine and trypsin protease inhibitors (TPI), as well as the potent indirect defense, the release of volatile terpenes that attract generalist predators to feeding herbivores. All these defenses could be fully restored by methyl‐JA (MeJA) treatment, with the exception of the increase in TPI activity, which was partially restored, suggesting the involvement of additional signals. The impaired ability to produce chemical defenses resulted in lower resistance to Manduca sexta attack, which could also be restored by MeJA treatment. Expression analysis using a cDNA microarray, specifically designed to analyze M. sexta‐induced gene expression in N. attenuata, revealed a pivotal role for LOX3‐produced oxylipins in upregulating defense genes (protease inhibitor, PI; xyloglucan endotransglucosylase/hydrolase, XTH; threonine deaminase, TD; hydroperoxide lyase, HPL), suppressing both downregulated growth genes (RUBISCO and photosystem II, PSII) and upregulated oxylipin genes (α‐dioxygenase, α‐DOX). By genetically manipulating signaling in a plant with a well‐characterized ecology, we demonstrate that the complex phenotypic changes that mediate herbivore resistance are controlled by a specific part of the oxylipin cascade.
The ethanol switch: a tool for tissue‐specific gene induction during plant development
Authors: Deveaux Yves , Peaucelle Alexis , Roberts Gethin R. , Coen Enrico , Simon Rudiger , Mizukami Yukiko , Traas Jan , Murray James A. H. , Doonan John H. , Laufs Patrick
Published: December 2003

Controlled gene expression in time and space is a powerful tool for the analysis of gene function during plant development. Here, we report ethanol inducible gene expression in defined sub‐domains of the shoot apical and floral meristems. For this, expression of an ethanol‐regulated transcription factor, ALCR, is restricted to precise domains using specific promoters. Gene expression activation is followed using reporters under the control of the alcA promoter, which responds to ALCR only in the presence of the ethanol. We demonstrate that precise control of spatially limited gene expression can be achieved. The kinetics of reporter gene activation and inactivation following a pulse of ethanol induction shows that the system is dynamic and suitable for precise temporal control of expression. The system is both flexible and robust, permitting simultaneous expression of two genes in a given domain or, conversely, the expression of a gene in two separate domains. We also show that this strategy can be applied to mis‐express genes with developmental roles, by manipulating expression of the SHOOT MERISTEMLESS (STM) and CYCLIN D3;1 (CYCD3;1) genes during plant development.
The NOMEGA gene required for female gametophyte development encodes the putative APC6/CDC16 component of the Anaphase Promoting Complex in Arabidopsis
Authors: Kwee Hong‐Sien , Sundaresan Venkatesan
Published: December 2003

Development of the female gametophyte involves several rounds of nuclear divisions during which nuclei are rearranged and finally cellularized to form a mature seven‐celled embryo sac. During these nuclear divisions, key proteins involved in the cell cycle need to be degraded quickly in order to facilitate both the metaphase–anaphase transition stage and late anaphase. Here, we report the characterization of an Arabidopsis mutant nomega, which results in arrest of the embryo sac development at the two‐nucleate stage. The NOMEGA gene product shows high homology to the APC6/cell division cycle (CDC)16 subunit of the Anaphase Promoting Complex/Cyclosome (APC/C). The phenotype of the nomega mutant is quite different from that of the hobbit mutant, which had suggested a role for the plant APC/C in auxin signalling. We show that nomega mutant embryo sacs are unable to degrade Cyclin B, an important APC/C substrate, providing further evidence of a role for the NOMEGA gene product and the plant APC/C in cell cycle progression during gametophyte development.
(R,S)‐Reticuline 7‐O‐methyltransferase and (R,S)‐norcoclaurine 6‐O‐methyltransferase of Papaver somniferum – cDNA cloning and characterization of methyl transfer enzymes of alkaloid biosynthesis in opium poppy
Authors: Ounaroon Anan , Decker Gabriele , Schmidt Jürgen , Lottspeich Friedrich , Kutchan Toni M.
Published: December 2003

S‐Adenosyl‐l‐methionine:(R,S)‐reticuline 7‐O‐methyltransferase converts reticuline to laudanine in tetrahydrobenzylisoquinoline biosynthesis in the opium poppy Papaver somniferum. This enzyme activity has not yet been detected in plants. A proteomic analysis of P. somniferum latex identified a gel spot that contained a protein(s) whose partial amino acid sequences were homologous to those of plant O‐methyltransferases. cDNA was amplified from P. somniferum RNA by reverse transcription PCR using primers based on these internal amino acid sequences. Recombinant protein was then expressed in Spodoptera frugiperda Sf9 cells in a baculovirus expression vector. Steady‐state kinetic measurements with one heterologously expressed enzyme and mass spectrometric analysis of the enzymatic products suggested that this unusual enzyme is capable of carrying through sequential O‐methylations on the isoquinoline and on the benzyl moiety of several substrates. The tetrahydrobenzylisoquinolines (R)‐reticuline (4.2 sec−1 mm−1), (S)‐reticuline (4.5 sec−1 mm−1), (R)‐protosinomenine (1.7 sec−1 mm−1), and (R,S)‐isoorientaline (1.4 sec−1 mm−1) as well as guaiacol (5.9 sec−1 mm−1) and isovanillic acid (1.2 sec−1 mm−1) are O‐methylated by the enzyme with the ratio kcat/K m shown in parentheses. A P. somniferum cDNA encoding (R,S)‐norcoclaurine 6‐O‐methyltransferase was similarly isolated and characterized. This enzyme was less permissive, methylating only (R,S)‐norcoclaurine (7.4 sec−1 mm−1), (R)‐norprotosinomenine (4.1 sec−1 mm−1), (S)‐norprotosinomenine (4.0 sec−1 mm−1) and (R,S)‐isoorientaline (1.0 sec−1 mm−1). A phylogenetic comparison of the amino acid sequences of these O‐methyltransferases to those from 28 other plant species suggests that these enzymes group more closely to isoquinoline biosynthetic O‐methyltransferases from Coptis japonica than to those from Thalictrum tuberosum that can O‐methylate both alkaloid and phenylpropanoid substrates.
Enhancement of stress tolerance in transgenic tobacco plants overexpressing Chlamydomonas glutathione peroxidase in chloroplasts or cytosol
Authors: Yoshimura Kazuya , Miyao Kazuhiro , Gaber Ahmed , Takeda Toru , Kanaboshi Haruo , Miyasaka Hitoshi , Shigeoka Shigeru
Published: December 2003

To evaluate the physiological potential of the defense system against hydroperoxidation of membrane‐lipid components caused by environmental stresses in higher plants, we generated transgenic tobacco plants expressing a glutathione peroxidase (GPX)‐like protein in the cytosol (TcGPX) or chloroplasts (TpGPX). The activities toward α‐linolenic acid hydroperoxide in TcGPX and TpGPX plants were 47.5–75.3 and 32.7–42.1 nmol min−1 mg−1 protein, respectively, while no activity was detected in wild‐type plants. The transgenic plants showed increased tolerance to oxidative stress caused by application of methylviologen (MV: 50 µm) under moderate light intensity (200 µE m−2 sec−1), chilling stress under high light intensity (4°C, 1000 µE m−2 sec−1), or salt stress (250 mm NaCl). Under these stresses, the lipid hydroperoxidation (the production of malondialdehyde (MDA)) of the leaves of TcGPX and TpGPX plants was clearly suppressed compared with that of wild‐type plants. Furthermore, the capacity of the photosynthetic and antioxidative systems in the transgenic plants remained higher than those of wild‐type plants under chilling or salt stress. These results clearly indicate that a high level of GPX‐like protein in tobacco plants functions to remove unsaturated fatty acid hydroperoxides generated in cellular membranes under stress conditions, leading to the maintenance of membrane integrity and increased tolerance to oxidative stress caused by various stress conditions.
The tomato resistance protein Bs4 is a predicted non‐nuclear TIR‐NB‐LRR protein that mediates defense responses to severely truncated derivatives of AvrBs4 and overexpressed AvrBs3
Authors: Schornack Sebastian , Ballvora Agim , Gürlebeck Doreen , Peart Jack , Ganal Martin , Baker Barbara , Bonas Ulla , Lahaye Thomas
Published: December 2003

The Lycopersicon esculentum Bs4 resistance (R) gene specifies recognition of Xanthomonas campestris pv. vesicatoria (Xcv) strains that express the cognate AvrBs4 avirulence protein. Bs4 was isolated by positional cloning and is predicted to encode a nucleotide‐binding leucine‐rich repeat (NB‐LRR) protein that is homologous to tobacco N and potato Y‐1 resistance proteins. Xcv infection tests demonstrate that Bs4 confers perception of AvrBs4 but not the 97% identical AvrBs3 protein. However, when delivered via Agrobacterium T‐DNA transfer, both, avrBs4 and avrBs3 trigger a Bs4‐dependent hypersensitive response, indicating that naturally occurring AvrBs3‐homologues provide a unique experimental platform for molecular dissection of recognition specificity. Transcript studies revealed intron retention in Bs4 transcripts. Yet, an intron‐deprived Bs4 derivative still mediates AvrBs4 detection, suggesting that the identified splice variants are not crucial to resistance. The L. pennellii bs4 allele, which is >98% identical to L. esculentum Bs4, has a Bs4‐like exon‐intron structure with exception of a splice polymorphism in intron 2 that causes truncation of the predicted bs4 protein. To test if the receptor‐ligand model is a valid molecular description of Bs4‐mediated AvrBs4 perception, we conducted yeast two‐hybrid studies. However, a direct interaction was not observed. Defense signaling of the Bs4‐governed reaction was studied in Nicotiana benthamiana by virus‐induced gene silencing and showed that Bs4‐mediated resistance is EDS1‐ and SGT1‐dependent.
The FUS3 transcription factor functions through the epidermal regulator TTG1 during embryogenesis in Arabidopsis
Authors: Tsuchiya Yuichiro , Nambara Eiji , Naito Satoshi , McCourt Peter
Published: December 2003

Loss‐of‐function mutations in the FUSCA3 (FUS3) gene of Arabidopsis result in alterations in cotyledon identity, inability to complete late seed maturation processes, and the premature activation of apical and root embryonic meristems, which indicates that this transcription factor is an essential regulator of embryogenesis. Although FUS3 shows a complex pattern of expression in the embryo, this gene is only required in the protoderm to carry out its functions. Moreover, the epidermal morphogenesis regulator TRANSPARENT TESTA GLABRA1 (TTG1) is negatively regulated by FUS3 in the embryo. When a loss‐of‐function ttg1 mutation is introduced into a fus3 mutant, a number of fus3‐related phenotypes are rescued, indicating a functional TTG1 gene is required to manifest the fus3 mutant phenotype. It therefore appears that one of the functions of FUS3 is to restrict the domain of expression of TTG1 during embryogenesis. The FUS3–TTG1 interaction is both maternal and zygotic, suggesting a complex relationship is required between these gene products to allow correct seed development.
TRANSPARENT TESTA 19 is involved in the accumulation of both anthocyanins and proanthocyanidins in Arabidopsis
Authors: Kitamura Satoshi , Shikazono Naoya , Tanaka Atsushi
Published: December 2003

Flavonoid compounds such as anthocyanins and proanthocyanidins (PAs; so‐called condensed tannins) have a multitude of functions in plants. They must be transported from the site of synthesis in the cytosol to their final destination, the vacuoles. Three models have been proposed for sequestering anthocyanins in vacuoles, but the transport machinery for PAs is poorly understood. Novel Arabidopsis mutants, transparent testa 19 (tt19), which were induced by ion beam irradiation, showed a great reduction of anthocyanin pigments in the vegetative parts as well as brown pigments in the seed coat. The TT19 gene was isolated by chromosome walking and a candidate gene approach, and was shown to be a member of the Arabidopsis glutathione S‐transferase (GST) gene family. Heterologous expression of a putative ortholog, petunia anthocyanin 9 (AN9), in tt19 complemented the anthocyanin accumulation but not the brown pigmentation in the seed coat. This suggests that the TT19 gene is required for vacuolar uptake of anthocyanins into vacuoles, but that it has also a function different from that of AN9. The depositional pattern of PA precursors in the mutant was different from that in the wild type. These results indicate that TT19 participates in the PA pathway as well as the anthocyanin pathway of Arabidopsis. As involvement of GST in the PA pathway was previously considered unlikely, the function of TT19 in the PA pathway is also discussed in the context of the putative transporter for PA precursors.
Two MAPK cascades, NPR1, and TGA transcription factors play a role in Pto‐mediated disease resistance in tomato
Authors: Ekengren Sophia K. , Liu Yule , Schiff Michael , Dinesh‐Kumar S. P. , Martin Gregory B.
Published: December 2003

The tomato Pto kinase confers resistance to the causative agent of bacterial speck disease, Pseudomonas syringae pv. tomato, by recognizing the pathogen effector proteins AvrPto or AvrPtoB. Pto‐mediated resistance requires multiple signal transduction pathways and has been shown to activate many defense responses including an oxidative burst, rapid changes in the expression of over 400 genes, and localized cell death. We have tested the role in Pto‐mediated resistance in tomato of a set of 21 genes from other species known to be involved in defense‐related signaling. Expression of each gene was suppressed by virus‐induced gene silencing (VIGS) and the effect on disease symptoms and bacterial growth during the tomato–Pseudomonas incompatible interaction was determined. We found that Pto‐mediated resistance was compromised by silencing of genes encoding two mitogen‐activated protein (MAP) kinase kinases, MEK1 and MEK2, two MAP kinases, NTF6 and wound‐induced protein kinase (WIPK), a key regulator of systemic acquired resistance (SAR), NPR1, and two transcription factors, TGA1a and TGA2.2. A lesser impact on Pto‐mediated resistance was observed in plants silenced for RAR1 and COI1. The identification of nine genes that play a role in resistance to bacterial speck disease both advances our knowledge of Pto signal transduction and demonstrates the conservation of many defense signaling components among diverse plant species.
A new method for rapid visualization of defects in leaf cuticle reveals five intrinsic patterns of surface defects in Arabidopsis
Authors: Tanaka Toshihiro , Tanaka Hirokazu , Machida Chiyoko , Watanabe Masaru , Machida Yasunori
Published: December 2003

The epidermis of higher plants generates the cuticle layer that covers the outer surface of each plant. The cuticle plays a crucial role in plant development, and some mutants with defective cuticle exhibit morphological abnormalities, such as the fusion of organs. The way in which the cuticle forms and its contribution to morphogenesis are poorly understood. Conventional detection of the cuticle by transmission electron microscopy (TEM) requires laborious procedures, which include fixation, staining with osmium, and preparation of ultra‐thin sections. It is also difficult to survey entire surfaces of expanded leaves because of the limited size of specimens that can be examined. Thus, TEM is unsuitable for large‐scale screening for mutants with defective cuticle. We describe here a rapid and inexpensive method, designated the toluidine‐blue (TB) test, for detection of cuticular defects in whole leaves. We demonstrated the validity of the TB test using mutants of Arabidopsis thaliana, including abnormal leaf shape1 (ale1), fiddlehead (fdh), and five eceriferum (cer) mutants, in which the structure and/or function of the cuticle is abnormal. Genetic screening for mutants using the TB test allowed us to identify seven loci. The cuticle‐defective regions of leaves of the mutants revealed five intrinsic patterns of surface defects (classes I through V), suggesting that formation of functional cuticle on leaves involves various spatially regulated factors.
BNS-Anfälle nach Hirnblutung - Arnica und Phosphorus
Authors: Hadulla Michael , Richter Olaf
Published: December 2003

Bericht über ein Kleinkind mit cerebralem Anfallsleiden (BNS und Grand mal) nach massiver postnataler Hirnblutung. Die kleine Patientin kommt wegen manifester Verhaltensauffälligkeiten (Hyperaktivität, Irritabilität, Schlafstörungen) unter antiepileptischer Therapie mit Luminal® (= Phenobarbital) und Vigabatrin (= Sabril). Da bekannt ist, dass Phenobarbital u.a. oben genannte psychische Störungen verursacht, erfolgt der homöopathische Therapieversuch. Die Antiepileptika wurden vorsichtig abgesetzt und gleichzeitig mit Homöopathica - Arnica und Phosphorus - therapiert. Das Verhalten der kleinen Patientin normalisierte sich ebenso wie das vorher hochpathologische EEG, und es traten keine neuen Anfälle auf.
The role of boundary conditions in a simple model of incipient vortex breakdown
Authors: Gallaire F. , Chomaz J.-M.
Published: December 2003

We consider incipient vortex breakdown and describe how infinitesimal perturbations may destabilize a columnar swirling jet. The framework is axisymmetric and inviscid following Wang and Rusak’s [J. Fluid Mech. 340, 177 (1997)] analysis. The goal of the present study is to relate the local properties of swirling flows in infinite pipes to their global stability properties in pipes of finite length. A spatial linear stability analysis is pursued which gives a complementary point of view to the subcritical/supercritical concept introduced by Benjamin [J. Fluid Mech. 14, 593 (1962)]. In contrast to supercritical flows which exhibit two neutral spatial branches traveling downstream and two counterpropagating evanescent spatial branches, subcritical flows exhibit a frequency range where all spatial branches are neutral, three of which travel downstream and one upstream. By using global energy budget arguments and monitoring how the upstream wave is reflected into the downstream waves and conversely, the inlet and outlet conditions are shown to drive the instability in the limit of long but finite pipes. Various inlet and outlet conditions are proposed that stabilize or destabilize the flow, depending on their ability to supply energy. The analysis demonstrates therefore that the global instability accounting for incipient vortex breakdown in Wang and Rusak’s model may arise from the combination of a locally neutral flow and suitable inlet and outlet conditions.
Nonequilibrium molecular-dynamics simulation of net evaporation and net condensation, and evaluation of the gas-kinetic boundary condition at the interphase
Authors: Meland Roar , Frezzotti Aldo , Ytrehus Tor , Hafskjold Bjørn
Published: December 2003

Algorithms for simulating steady net evaporation and net condensation with molecular dynamics are presented. The evaporation and condensation coefficients are calculated, showing that they are not equal outside equilibrium. The distribution function at the interphase boundary is evaluated. There is a drift away from the interphase in the distribution function for the evaporated molecules and a drift velocity towards the interphase for the reflected molecules, both for net evaporation and for net condensation.
Luminescence and visible upconversion in nanocrystalline ZrO2:Er3+
Authors: De la Rosa-Cruz E. , Dı́az-Torres L. A. , Rodrı́guez-Rojas R. A. , Meneses-Nava M. A. , Barbosa-Garcı́a O. , Salas P.
Published: December 2003

The structural and luminescence properties of erbium doped zirconium oxide prepared by the sol-gel processes were analyzed. The annealed powders presented a concentration dependent crystallite sizes and crystalline phase, ranging from 28 to 46 nm and from 40 to 96% for the monoclinic phase, respectively. Green (545 nm) and red (680 nm) emissions bands were observed with 489 and 962 nm excitation. Experimental results showed that the emission bands can be tuned by controlling the Er3+ concentration and that the red band is almost quenched with 489 nm whereas it is enhanced with 962 nm excitation. The nature of this behavior is discussed taking into account the nonradiative energy transfer and cross-relaxation process.
Island chain formation during liquid phase epitaxy of SiGe on silicon
Authors: Hanke M. , Raidt H. , Köhler R. , Wawra H.
Published: December 2003

We report on the evolution of lateral ordering of SiGe nanoscale islands on Si(001), which have been grown by means of liquid phase epitaxy in the Stranski-Krastanow mode. Applying post-growth atomic force microscopy on different sample areas covered by different island densities, we could trace ex-situ the development of extended island chains along the 〈100〉-directions. The linear alignment happens by further nucleation of islands at the end of an already existing formation. Those direct observations will be discussed in terms of finite element strain energy calculations around various island configurations.
Characterization of tris (8-hydroxyquinoline) aluminum (Alq3) by energy-filtering transmission electron microscopy
Authors: Yamanaka M. , Kudo J.
Published: December 2003

Electronic structure of tris (8-hydroxyquinoline) aluminum (Alq3) was characterized by energy-filtering transmission electron microscopy (EFTEM). Three energy loss peaks were observed with reasonable energy resolution of 0.5–0.7 eV. These peaks were ascribed to the ionization (6.4 eV), La1 transition (3.3 eV) and Bb1 transition (4.7 eV) processes in this material, respectively. The present result indicates that EFTEM provides an effective means to characterize the electronic structure of organic materials with nanometer resolution.
Concentration efficiency of doping in phosphors: Investigation of the copper- and aluminum-doped zinc sulfide
Authors: Qi Lai , Lee Burtrand I. , Gu Xuejun , Grujicic Mica , Samuels William D. , Exarhos Gregory J.
Published: December 2003

We studied the effect of dopant concentration in ZnS:Cu, Al phosphor. Photoluminescent (PL) intensity of the chemically etched phosphor particles increased up to 140%, which proved the existence of a dopant concentration gradient. Calculation revealed the quantitative relationship between the dopant concentration and the luminescent intensity by relating the concentration gradient to the PL intensity. The result showed that the most efficient concentration is 100 ppm copper and the concentration quenching starts at 152 ppm.
Internal quantum efficiency of highly-efficient InxGa1−xN-based near-ultraviolet light-emitting diodes
Authors: Watanabe Satoshi , Yamada Norihide , Nagashima Masakazu , Ueki Yusuke , Sasaki Chiharu , Yamada Yoichi , Taguchi Tsunemasa , Tadatomo Kazuyuki , Okagawa Hiroaki , Kudo Hiromitsu
Published: December 2003

The internal quantum efficiency (IQE) of highly-efficient near-UV light-emitting diodes, which shows an external quantum efficiency of 43% at 406 nm, has been measured by excitation power and temperature-dependent photoluminescence (PL). Assuming peak PL quantum efficiency at 8 K is 100%, peak IQE at 300 K was measured to be as high as 63%. At the injected carrier density, which corresponds to 20 mA current injection, IQE and light extraction efficiency were estimated to be about 54% and 80%, respectively.
Hydrostatic pressure dependence of the fundamental bandgap of InN and In-rich group III nitride alloys
Authors: Li S. X. , Wu J. , Haller E. E. , Walukiewicz W. , Shan W. , Lu Hai , Schaff William J.
Published: December 2003

We report studies of the hydrostatic pressure dependence of the fundamental bandgap of InN, In-rich In1−xGaxN (0<x<0.5) and In1−xAlxN (x=0.25) alloys. The bandgap shift with pressure was measured by optical absorption experiments with samples mounted in diamond anvil cells. The pressure coefficient is found to be 3.0±0.1 meV/kbar for InN. A comparison between our results and previously reported theoretical calculations is presented and discussed. Together with previous experimental results, our data suggest that the pressure coefficients of group III nitride alloys have only a weak dependence on the alloy composition. The photoluminescence signals appear to yield significantly smaller pressure coefficients than the bandgap from absorption measurements. This is due to emission associated with highly localized states. Based on these results, the absolute deformation potentials of the conduction and valence band edges are estimated.
Charge injection versus space-charge-limited current in organic light-emitting diodes
Authors: Arkhipov V. I. , von Seggern H. , Emelianova E. V.
Published: December 2003

A unified model of hopping carrier injection and space-charge-limited current (SCLC) in disordered organic materials is formulated. It is shown that, contrary to what one would intuitively expect, a metal contact with the injection barrier as high as 1 eV can be still an Ohmic contact at low temperatures providing conditions for the hopping SCLC.