bluuebunny/crossref_metadata_2025 huggingface dataset:
Proteomic Analysis of Different Mutant Genotypes of Arabidopsis Led to the Identification of 11 Proteins Correlating with Adventitious Root Development
Authors: Sorin Céline , Negroni Luc , Balliau Thierry , Corti Hélène , Jacquemot Marie-Pierre , Davanture Marlène , Sandberg Göran , Zivy Michel , Bellini Catherine
Published: December 2005

A lack of competence to form adventitious roots by cuttings or explants in vitro occurs routinely and is an obstacle for the clonal propagation and rapid fixation of elite genotypes. Adventitious rooting is known to be a quantitative genetic trait. We performed a proteomic analysis of Arabidopsis (Arabidopsis thaliana) mutants affected in their ability to develop adventitious roots in order to identify associated molecular markers that could be used to select genotypes for their rooting ability and/or to get further insight into the molecular mechanisms controlling adventitious rooting. Comparison of two-dimensional gel electrophoresis protein profiles resulted in the identification of 11 proteins whose abundance could be either positively or negatively correlated with endogenous auxin content, the number of adventitious root primordia, and/or the number of mature adventitious roots. One protein was negatively correlated only to the number of root primordia and two were negatively correlated to the number of mature adventitious roots. Two putative chaperone proteins were positively correlated only to the number of primordia, and, interestingly, three auxin-inducible GH3-like proteins were positively correlated with the number of mature adventitious roots. The others were correlated with more than one parameter. The 11 proteins are predicted to be involved in different biological processes, including the regulation of auxin homeostasis and light-associated metabolic pathways. The results identify regulatory pathways associated with adventitious root formation and represent valuable markers that might be used for the future identification of genotypes with better rooting abilities.
Analysis of Freeze-Thaw Embolism in Conifers. The Interaction between Cavitation Pressure and Tracheid Size
Authors: Pittermann Jarmila , Sperry John S.
Published: December 2005

Ice formation in the xylem sap produces air bubbles that under negative xylem pressures may expand and cause embolism in the xylem conduits. We used the centrifuge method to evaluate the relationship between freeze-thaw embolism and conduit diameter across a range of xylem pressures (P  x) in the conifers Pinus contorta and Juniperus scopulorum. Vulnerability curves showing loss of conductivity (embolism) with P  x down to −8 MPa were generated with versus without superimposing a freeze-thaw treatment. In both species, the freeze-thaw plus water-stress treatment caused more embolism than water stress alone. We estimated the critical conduit diameter (D  f) above which a tracheid will embolize due to freezing and thawing and found that it decreased from 35 μm at a P  x of −0.5 MPa to 6 μm at −8 MPa. Further analysis showed that the proportionality between diameter of the air bubble nucleating the cavitation and the diameter of the conduit (kL) declined with increasingly negative P  x. This suggests that the bubbles causing cavitation are smaller in proportion to tracheid diameter in narrow tracheids than in wider ones. A possible reason for this is that the rate of dissolving increases with bubble pressure, which is inversely proportional to bubble diameter (La Place's law). Hence, smaller bubbles shrink faster than bigger ones. Last, we used the empirical relationship between P  x and D  f to model the freeze-thaw response in conifer species.
Phloem Loading in Two Scrophulariaceae Species. What Can Drive Symplastic Flow via Plasmodesmata?
Authors: Voitsekhovskaja Olga V. , Koroleva Olga A. , Batashev Denis R. , Knop Christian , Tomos A. Deri , Gamalei Yuri V. , Heldt Hans-Walter , Lohaus Gertrud
Published: December 2005

To determine the driving forces for symplastic sugar flux between mesophyll and phloem, gradients of sugar concentrations and osmotic pressure were studied in leaf tissues of two Scrophulariaceae species, Alonsoa meridionalis and Asarina barclaiana. A. meridionalis has a typical symplastic configuration of minor-vein phloem, i.e. intermediary companion cells with highly developed plasmodesmal connections to bundle-sheath cells. In A. barclaiana, two types of companion cells, modified intermediary cells and transfer cells, were found in minor-vein phloem, giving this species the potential to have a complex phloem-loading mode. We identified all phloem-transported carbohydrates in both species and analyzed the levels of carbohydrates in chloroplasts, vacuoles, and cytoplasm of mesophyll cells by nonaqueous fractionation. Osmotic pressure was measured in single epidermal and mesophyll cells and in whole leaves and compared with calculated values for phloem sap. In A. meridionalis, a 2-fold concentration gradient for sucrose between mesophyll and phloem was found. In A. barclaiana, the major transported carbohydrates, sucrose and antirrhinoside, were present in the phloem in 22- and 6-fold higher concentrations, respectively, than in the cytoplasm of mesophyll cells. The data show that diffusion of sugars along their concentration gradients is unlikely to be the major mechanism for symplastic phloem loading if this were to occur in these species. We conclude that in both A. meridionalis and A. barclaiana, apoplastic phloem loading is an indispensable mechanism and that symplastic entrance of solutes into the phloem may occur by mass flow. The conditions favoring symplastic mass flow into the phloem are discussed.
The DMI1 and DMI2 Early Symbiotic Genes of Medicago truncatula Are Required for a High-Affinity Nodulation Factor-Binding Site Associated to a Particulate Fraction of Roots
Authors: Hogg Bridget V. , Cullimore Julie V. , Ranjeva Raoul , Bono Jean-Jacques
Published: December 2005

The establishment of the legume-rhizobia symbiosis between Medicago spp. and Sinorhizobium meliloti is dependent on the production of sulfated lipo-chitooligosaccharidic nodulation (Nod) factors by the bacterial partner. In this article, using a biochemical approach to characterize putative Nod factor receptors in the plant host, we describe a high-affinity binding site (K  d = 0.45 nm) for the major Nod factor produced by S. meliloti. This site is termed Nod factor-binding site 3 (NFBS3). NFBS3 is associated to a high-density fraction prepared from roots of Medicago truncatula and shows binding specificity for lipo-chitooligosaccharidic structures. As for the previously characterized binding sites (NFBS1 and NFBS2), NFBS3 does not recognize the sulfate group on the S. meliloti Nod factor. Studies of Nod factor binding in root extracts of early symbiotic mutants of M. truncatula reveals that the new site is present in Nod factor perception and does not make infections 3 (dmi3) mutants but is absent in dmi1 and dmi2 mutants. Roots and cell cultures of all these mutants still contain sites similar to NFBS1 and NFBS2, respectively. These results suggest that NFBS3 is different from NFBS2 and NFBS1 and is dependent on the common symbiotic genes DMI1 and DMI2 required for establishment of symbioses with both rhizobia and arbuscular mycorrhizal fungi. The potential role of this site in the establishment of root endosymbioses is discussed.
A coumaroyl-ester-3-hydroxylase Insertion Mutant Reveals the Existence of Nonredundant meta-Hydroxylation Pathways and Essential Roles for Phenolic Precursors in Cell Expansion and Plant Growth
Authors: Abdulrazzak Nawroz , Pollet Brigitte , Ehlting Jürgen , Larsen Kim , Asnaghi Carole , Ronseau Sebastien , Proux Caroline , Erhardt Mathieu , Seltzer Virginie , Renou Jean-Pierre , Ullmann Pascaline , Pauly Markus , Lapierre Catherine , Werck-Reichhart Danièle
Published: December 2005

Cytochromes P450 monooxygenases from the CYP98 family catalyze the meta-hydroxylation step in the phenylpropanoid biosynthetic pathway. The ref8 Arabidopsis (Arabidopsis thaliana) mutant, with a point mutation in the CYP98A3 gene, was previously described to show developmental defects, changes in lignin composition, and lack of soluble sinapoyl esters. We isolated a T-DNA insertion mutant in CYP98A3 and show that this mutation leads to a more drastic inhibition of plant development and inhibition of cell growth. Similar to the ref8 mutant, the insertion mutant has reduced lignin content, with stem lignin essentially made of p-hydroxyphenyl units and trace amounts of guaiacyl and syringyl units. However, its roots display an ectopic lignification and a substantial proportion of guaiacyl and syringyl units, suggesting the occurrence of an alternative CYP98A3-independent meta-hydroxylation mechanism active mainly in the roots. Relative to the control, mutant plantlets produce very low amounts of sinapoyl esters, but accumulate flavonol glycosides. Reduced cell growth seems correlated with alterations in the abundance of cell wall polysaccharides, in particular decrease in crystalline cellulose, and profound modifications in gene expression and homeostasis reminiscent of a stress response. CYP98A3 thus constitutes a critical bottleneck in the phenylpropanoid pathway and in the synthesis of compounds controlling plant development. CYP98A3 cosuppressed lines show a gradation of developmental defects and changes in lignin content (40% reduction) and structure (prominent frequency of p-hydroxyphenyl units), but content in foliar sinapoyl esters is similar to the control. The purple coloration of their leaves is correlated to the accumulation of sinapoylated anthocyanins.
MICROTUBULE ORGANIZATION 1 Regulates Structure and Function of Microtubule Arrays during Mitosis and Cytokinesis in the Arabidopsis Root
Authors: Kawamura Eiko , Himmelspach Regina , Rashbrooke Madeleine C. , Whittington Angela T. , Gale Kevin R. , Collings David A. , Wasteneys Geoffrey O.
Published: December 2005

MICROTUBULE ORGANIZATION 1 (MOR1) is a plant member of the highly conserved MAP215/Dis1 family of microtubule-associated proteins. Prior studies with the temperature-sensitive mor1 mutants of Arabidopsis (Arabidopsis thaliana), which harbor single amino acid substitutions in an N-terminal HEAT repeat, proved that MOR1 regulates cortical microtubule organization and function. Here we demonstrate by use of live cell imaging and immunolabeling that the mor1-1 mutation generates specific defects in the microtubule arrays of dividing vegetative cells. Unlike the universal cortical microtubule disorganization in elongating mor1-1 cells, disruption of mitotic and cytokinetic microtubule arrays was not detected in all dividing cells. Nevertheless, quantitative analysis identified distinct defects in preprophase bands (PPBs), spindles, and phragmoplasts. In nearly one-half of dividing cells at the restrictive temperature of 30°C, PPBs were not detected prior to spindle formation, and those that did form were often disrupted. mor1-1 spindles and phragmoplasts were short and abnormally organized and persisted for longer times than in wild-type cells. The reduced length of these arrays predicts that the component microtubule lengths are also reduced, suggesting that microtubule length is a critical determinant of spindle and phragmoplast structure, orientation, and function. Microtubule organizational defects led to aberrant chromosomal arrangements, misaligned or incomplete cell plates, and multinucleate cells. Antiserum raised against an N-terminal MOR1 sequence labeled the full length of microtubules in interphase arrays, PPBs, spindles, and phragmoplasts. Continued immunolabeling of the disorganized and short microtubules of mor1-1 at the restrictive temperature demonstrated that the mutant mor1-1L174F protein loses function without dissociating from microtubules, providing important insight into the mechanism by which MOR1 may regulate microtubule length.
Cell Wall Proteome in the Maize Primary Root Elongation Zone. I. Extraction and Identification of Water-Soluble and Lightly Ionically Bound Proteins
Authors: Zhu Jinming , Chen Sixue , Alvarez Sophie , Asirvatham Victor S. , Schachtman Daniel P. , Wu Yajun , Sharp Robert E.
Published: December 2005

Cell wall proteins (CWPs) play important roles in various processes, including cell elongation. However, relatively little is known about the composition of CWPs in growing regions. We are using a proteomics approach to gain a comprehensive understanding of the identity of CWPs in the maize (Zea mays) primary root elongation zone. As the first step, we examined the effectiveness of a vacuum infiltration-centrifugation technique for extracting water-soluble and loosely ionically bound (fraction 1) CWPs from the root elongation zone. The purity of the CWP extract was evaluated by comparing with total soluble proteins extracted from homogenized tissue. Several lines of evidence indicated that the vacuum infiltration-centrifugation technique effectively enriched for CWPs. Protein identification revealed that 84% of the CWPs were different from the total soluble proteins. About 40% of the fraction 1 CWPs had traditional signal peptides and 33% were predicted to be nonclassical secretory proteins, whereas only 3% and 11%, respectively, of the total soluble proteins were in these categories. Many of the CWPs have previously been shown to be involved in cell wall metabolism and cell elongation. In addition, maize has type II cell walls, and several of the CWPs identified in this study have not been identified in previous cell wall proteomics studies that have focused only on type I walls. These proteins include endo-1,3;1,4-β-d-glucanase and α-l-arabinofuranosidase, which act on the major polysaccharides only or mainly present in type II cell walls.
Transcript Analysis of Early Nodulation Events in Medicago truncatula
Authors: Lohar Dasharath Prasad , Sharopova Natalya , Endre Gabriella , Peñuela Silvia , Samac Deborah , Town Christopher , Silverstein Kevin A.T. , VandenBosch Kathryn A.
Published: December 2005

Within the first 72 h of the interaction between rhizobia and their host plants, nodule primordium induction and infection occur. We predicted that transcription profiling of early stages of the symbiosis between Medicago truncatula roots and Sinorhizobium meliloti would identify regulated plant genes that likely condition key events in nodule initiation. Therefore, using a microarray with about 6,000 cDNAs, we compared transcripts from inoculated and uninoculated roots corresponding to defined stages between 1 and 72 h post inoculation (hpi). Hundreds of genes of both known and unknown function were significantly regulated at these time points. Four stages of the interaction were recognized based on gene expression profiles, and potential marker genes for these stages were identified. Some genes that were regulated differentially during stages I (1 hpi) and II (6–12 hpi) of the interaction belong to families encoding proteins involved in calcium transport and binding, reactive oxygen metabolism, and cytoskeleton and cell wall functions. Genes involved in cell proliferation were found to be up-regulated during stages III (24–48 hpi) and IV (72 hpi). Many genes that are homologs of defense response genes were up-regulated during stage I but down-regulated later, likely facilitating infection thread progression into the root cortex. Additionally, genes putatively involved in signal transduction and transcriptional regulation were found to be differentially regulated in the inoculated roots at each time point. The findings shed light on the complexity of coordinated gene regulation and will be useful for continued dissection of the early steps in symbiosis.
The Outcomes of Concentration-Specific Interactions between Salicylate and Jasmonate Signaling Include Synergy, Antagonism, and Oxidative Stress Leading to Cell Death
Authors: Mur Luis A.J. , Kenton Paul , Atzorn Rainer , Miersch Otto , Wasternack Claus
Published: December 2005

Salicylic acid (SA) has been proposed to antagonize jasmonic acid (JA) biosynthesis and signaling. We report, however, that in salicylate hydroxylase-expressing tobacco (Nicotiana tabacum) plants, where SA levels were reduced, JA levels were not elevated during a hypersensitive response elicited by Pseudomonas syringae pv phaseolicola. The effects of cotreatment with various concentrations of SA and JA were assessed in tobacco and Arabidopsis (Arabidopsis thaliana). These suggested that there was a transient synergistic enhancement in the expression of genes associated with either JA (PDF1.2 [defensin] and Thi1.2 [thionin]) or SA (PR1 [PR1a-β-glucuronidase in tobacco]) signaling when both signals were applied at low (typically 10–100 μ  m) concentrations. Antagonism was observed at more prolonged treatment times or at higher concentrations. Similar results were also observed when adding the JA precursor, α-linolenic acid with SA. Synergic effects on gene expression and plant stress were NPR1- and COI1-dependent, SA- and JA-signaling components, respectively. Electrolyte leakage and Evans blue staining indicated that application of higher concentrations of SA + JA induced plant stress or death and elicited the generation of apoplastic reactive oxygen species. This was indicated by enhancement of hydrogen peroxide-responsive AoPR10-β-glucuronidase expression, suppression of plant stress/death using catalase, and direct hydrogen peroxide measurements. Our data suggests that the outcomes of JA-SA interactions could be tailored to pathogen/pest attack by the relative concentration of each hormone.
ARABINAN DEFICIENT 1 Is a Putative Arabinosyltransferase Involved in Biosynthesis of Pectic Arabinan in Arabidopsis
Authors: Harholt Jesper , Jensen Jacob Krüger , Sørensen Susanne Oxenbøll , Orfila Caroline , Pauly Markus , Scheller Henrik Vibe
Published: December 2005

The function of a putative glycosyltransferase (At2g35100) was investigated in Arabidopsis (Arabidopsis thaliana). The protein is predicted to be a type 2 membrane protein with a signal anchor. Two independent mutant lines with T-DNA insertion in the ARABINAN DEFICIENT 1 (ARAD1) gene were analyzed. The gene was shown to be expressed in all tissues but particularly in vascular tissues of leaves and stems. Analysis of cell wall polysaccharides isolated from leaves and stems showed that arabinose content was reduced to about 75% and 46%, respectively, of wild-type levels. Immunohistochemical analysis indicated a specific decrease in arabinan with no change in other pectic domains or in glycoproteins. The cellular structure of the stem was also not altered. Isolated rhamnogalacturonan I from mutant tissues contained only about 30% of the wild-type amount of arabinose, confirming the specific deficiency in arabinan. Linkage analysis showed that the small amount of arabinan present in mutant tissue was structurally similar to that of the wild type. Transformation of mutant plants with the ARAD1 gene driven by the 35S promoter led to full complementation of the phenotype, but none of the transformants had more arabinan than the wild-type level. The data suggest that ARAD1 is an arabinan α-1,5-arabinosyltransferase. To our knowledge, the identification of other l-arabinosyltransferases has not been published.
Pea Seed Mitochondria Are Endowed with a Remarkable Tolerance to Extreme Physiological Temperatures
Authors: Stupnikova Irina , Benamar Abdelilah , Tolleter Dimitri , Grelet Johann , Borovskii Genadii , Dorne Albert-Jean , Macherel David
Published: December 2005

Most seeds are anhydrobiotes, relying on an array of protective and repair mechanisms, and seed mitochondria have previously been shown to harbor stress proteins probably involved in desiccation tolerance. Since temperature stress is a major issue for germinating seeds, the temperature response of pea (Pisum sativum) seed mitochondria was examined in comparison with that of mitochondria from etiolated epicotyl, a desiccation-sensitive tissue. The functional analysis illustrated the remarkable temperature tolerance of seed mitochondria in response to both cold and heat stress. The mitochondria maintained a well-coupled respiration between −3.5°C and 40°C, while epicotyl mitochondria were not efficient below 0°C and collapsed above 30°C. Both mitochondria exhibited a similar Arrhenius break temperature at 7°C, although they differed in phospholipid composition. Seed mitochondria had a lower phosphatidylethanolamine-to-phosphatidylcholine ratio, fewer unsaturated fatty acids, and appeared less susceptible to lipid peroxidation. They also accumulated large amounts of heat shock protein HSP22 and late-embryogenesis abundant protein PsLEAm. The combination of membrane composition and stress protein accumulation required for desiccation tolerance is expected to lead to an unusually wide temperature tolerance, contributing to the fitness of germinating seeds in adverse conditions. The unique oxidation of external NADH at low temperatures found with several types of mitochondria may play a central role in maintaining energy homeostasis during cold shock, a situation often encountered by sessile and ectothermic higher plants.
Identification of the Flavonoid Hydroxylases from Grapevine and Their Regulation during Fruit Development
Authors: Bogs Jochen , Ebadi Ali , McDavid Debra , Robinson Simon P.
Published: December 2005

Flavonoids are important secondary metabolites in many fruits, and their hydroxylation pattern determines their color, stability, and antioxidant capacity. Hydroxylation of the B-ring of flavonoids is catalyzed by flavonoid 3′-hydroxylase (F3′H) and flavonoid 3′,5′-hydroxylase (F3′5′H), and may also require cytochrome b5. We report the identification of genes encoding F3′H, F3′5′H, and a putative cytochrome b5 from grapevine (Vitis vinifera L. cv Shiraz) and their transcriptional regulation in fruit. Functionality of the genes VvF3′H and VvF3′5′H1 was demonstrated by ectopic expression in petunia (Petunia hybrida), which altered flower color and flavonoid composition as expected. VvF3′H was expressed in grapes before flowering, when 3′-hydroxylated flavonols are made, and all three genes were expressed after flowering, when proanthocyanidins (PAs) are synthesized. In berry skin, expression of all three genes was low at the onset of ripening (véraison) but increased after véraison concomitant with the accumulation of 3′- and 3′,5′-hydroxylated anthocyanins. VvF3′H and VvCytoB5 were expressed in seeds but not VvF3′5′H1, consistent with the accumulation of 3′-hydroxylated PAs in this tissue. VvCytoB5 expression was correlated with expression of both VvF3′H and VvF3′5′H1 in the different grape tissues. In contrast to red grapes, where VvF3′H, VvF3′5′H1, and VvCytoB5 were highly expressed during ripening, the expression of VvF3′5′H1 and VvCytoB5 in white grapes during ripening was extremely low, suggesting a difference in transcriptional regulation. Our results show that temporal and tissue-specific expression of VvF3′H, VvF3′5′H1, and VvCytoB5 in grapes is coordinated with the accumulation of the respective hydroxylated flavonols and PAs, as well as anthocyanins. Understanding the regulation of flavonoid hydroxylases could be used to modify flavonoid composition of fruits.
The Onset of Gravisensitivity in the Embryonic Root of Flax
Authors: Ma Zhong , Hasenstein Karl H.
Published: December 2005

Vertical orientation of emerging roots typically is the first response of plants to gravity. Although root gravitropism has been studied extensively, no conclusive data on the onset of gravisensing exist. We determined the inception of gravisensitivity in flax (Linum usitatissimum) roots by clinorotating germinating seeds after various periods of static orientation (gravistimulation) of imbibed seeds. Gravitropic competency was established about 8 h after imbibition, 11 h prior to germination. The time was determined based on 50% of the newly emerged roots curving in the direction of the gravity vector during static imbibition, despite subsequent clinorotation. The threshold value was affected by the orientation of the seeds. Upward orientation of the micropyle/radicle reduced the number of graviresponding roots to about one-half. Prolonged clinorotation weakened the graviresponse. Gravisensing was accompanied by the development of amyloplasts, but the actin cytoskeleton was not involved because imbibition in Latrunculin B did not affect the onset of gravisensitivity or germination, and the development of F-actin in untreated controls was observed only after the onset of gravisensitivity.
The Arabidopsis Receptor Kinase FLS2 Binds flg22 and Determines the Specificity of Flagellin Perception
Authors: Chinchilla Delphine , Bauer Zsuzsa , Regenass Martin , Boller Thomas , Felix Georg
Published: December 2005

Flagellin, the main building block of the bacterial flagellum, acts as a pathogen-associated molecular pattern triggering the innate immune response in animals and plants. In Arabidopsis thaliana, the Leu-rich repeat transmembrane receptor kinase FLAGELLIN SENSITIVE2 (FLS2) is essential for flagellin perception. Here, we demonstrate the specific interaction of the elicitor-active epitope flg22 with the FLS2 protein by chemical cross-linking and immunoprecipitation. The functionality of this receptor was further tested by heterologous expression of the Arabidopsis FLS2 gene in tomato (Lycopersicon esculentum) cells. The perception of flg22 in tomato differs characteristically from that in Arabidopsis. Expression of Arabidopsis FLS2 conferred an additional flg22-perception system on the cells of tomato, which showed all of the properties characteristic of the perception of this elicitor in Arabidopsis. In summary, these results show that FLS2 constitutes the pattern-recognition receptor that determines the specificity of flagellin perception.
A Rice Glutamate Receptor–Like Gene Is Critical for the Division and Survival of Individual Cells in the Root Apical Meristem
Authors: Li Jing , Zhu Shihua , Song Xinwei , Shen Yi , Chen Hanming , Yu Jie , Yi Keke , Liu Yanfen , Karplus Valerie J. , Wu Ping , Deng Xing Wang
Published: December 2005

Glu receptors are known to function as Glu-activated ion channels that mediate mostly excitatory neurotransmission in animals. Glu receptor–like genes have also been reported in higher plants, although their function is largely unknown. We have identified a rice (Oryza sativa) Glu receptor–like gene, designated GLR3.1, in which mutation by T-DNA insertion caused a short-root mutant phenotype. Histology and DNA synthesis analyses revealed that the mutant root meristematic activity is distorted and is accompanied by enhanced programmed cell death. Our results supply genetic evidence that a plant Glu receptor–like gene, rice GLR3.1, is essential for the maintenance of cell division and individual cell survival in the root apical meristem at the early seedling stage.
Increased Expression of MAP KINASE KINASE7 Causes Deficiency in Polar Auxin Transport and Leads to Plant Architectural Abnormality inArabidopsis
Authors: Dai Ya , Wang Huanzhong , Li Baohua , Huang Juan , Liu Xinfang , Zhou Yihua , Mou Zhonglin , Li Jiayang
Published: December 2005

Polar auxin transport (PAT) plays a crucial role in the regulation of many aspects of plant growth and development. We report the characterization of a semidominant Arabidopsis thaliana bushy and dwarf1 (bud1) mutant. Molecular genetic analysis indicated that the bud1 phenotype is a result of increased expression of Arabidopsis MAP KINASE KINASE7 (MKK7), a member of plant mitogen-activated protein kinase kinase group D. We showed that BUD1/MKK7 is a functional kinase and that the kinase activity is essential for its biological functions. Compared with the wild type, the bud1 plants develop significantly fewer lateral roots, simpler venation patterns, and a quicker and greater curvature in the gravitropism assay. In addition, the bud1 plants have shorter hypocotyls at high temperature (29°C) under light, which is a characteristic feature of defective auxin action. Determination of tritium-labeled indole-3-acetic acid transport showed that the increased expression of MKK7 in bud1 or the repressed expression in MKK7 antisense transgenic plants causes deficiency or enhancement in auxin transport, indicating that MKK7 negatively regulates PAT. This conclusion was further substantiated by genetic and phenotypic analyses of double mutants generated from crosses between bud1 and the auxin-related mutants axr3-3, tir1-1, doc1-1, and atmdr1-1.
Cyclosporine‐responsive thrombocytopenia in a patient with chloramphenicol‐associated myelodysplastic syndrome
Authors: Arber Caroline , Buser Andreas , Heim Dominik , Gratwohl Alois , Tichelli André , Passweg Jakob R.
Published: January 2006

Abstract:  A 64‐yr‐old patient with myelodysplastic syndrome (MDS), with refractory cytopenia with multilineage dysplasia subtype following chloramphenicol exposure received immunosuppressive treatment with antithymocyte globulin and cyclosporine (CsA). Complete remission was achieved and CsA was tapered after 2.5 yr. Shortly after CsA withdrawal, the patient relapsed with thrombocytopenia but responded to restoration of CsA. This case illustrates that immune‐mediated mechanisms of cytopenia in MDS may be dependent on continued immunosuppressive treatment similar to aplastic anemia.
Coupling long‐term studies with meta‐analysis to investigate impacts of non‐native crayfish on zoobenthic communities
Authors: MCCARTHY JULIA M. , HEIN CATHERINE L. , OLDEN JULIAN D. , JAKE VANDER ZANDEN M.
Published: January 2006

1. Biological invasions are widely recognised as a significant component of human‐caused environmental change and a primary threat to native biodiversity. The negative impacts of species invasions are particularly evident for freshwater crayfish faunas.

2. This study provides novel insight into the ecological effects of native and non‐native crayfish on zoobenthic communities (with emphasis on the non‐native rusty crayfish,Orconectes rusticus) across broad scales by combining a meta‐analysis of small‐scale experimental studies with a long‐term observational study conducted over a 24 year period in Sparkling Lake, Wisconsin, U.S.A. (46°00′N, 89°42′W).

3. The meta‐analysis summarised quantitatively the results of cage experiments for seven species of crayfish spanning four continents. We found that total zoobenthos densities (primarily Gastropoda and Diptera) were significantly lower in treatments containing crayfish relative to controls; a result that was significant for non‐native crayfish but not for crayfish in their native range, perhaps owing to a small sample size. In contrast to other species, rusty crayfish were also negatively associated with Ephemeroptera.

4. Results from the time series analysis comparing temporal trends in rusty crayfish and invertebrate abundances from Sparkling Lake were consistent with the findings from the meta‐analysis. Rusty crayfish were negatively correlated with the abundance of total zoobenthos, Diptera, Ephemeroptera and Odonata, as well as families of Trichoptera.

5. By coupling the results from short and long‐term research, our study offers greater insight into the nature of crayfish‐invertebrate interactions in aquatic systems, revealing consistent effects of invasive crayfish on native fauna. The control and management of invasive species is facilitated by the knowledge that well executed small‐scale studies may be extrapolated to understand larger‐scale ecological interactions.
Influences of logging history and riparian forest characteristics on macroinvertebrates and brook trout (Salvelinus fontinalis) in headwater streams (New Hampshire, U.S.A.)
Authors: NISLOW KEITH H. , LOWE WINSOR H.
Published: January 2006

1. Logging can strongly affect stream macroinvertebrate communities, but the direction and magnitude of these effects and their implications for trout abundance are frequently region‐specific and difficult to predict.

2. In first‐order streams in northern New England (U.S.A.) representing a chronosequence of logging history (<2 to >80 years since logging), we measured riparian forest conditions, stream macroinvertebrate community characteristics and brook trout (Salvelinus fontinalis) abundance. Principal component analysis was used to collapse forest data into two independent variables representing variation in logging history, riparian forest structure and canopy cover. We used these data to test whether logging history and associated forest conditions were significant predictors of macroinvertebrate abundance and functional feeding group composition, and whether brook trout abundance was related to logging‐associated variation in invertebrate communities.

3. Catchments with high PC1 scores (recently logged, high‐density stands with low mean tree diameter) and low PC2 scores (low canopy cover) had significantly higher total macroinvertebrate abundance, particularly with respect to chironomid larvae (low PC2 scores) and invertebrates in the grazer functional feeding group (high PC1 scores). In contrast, proportional representation of macroinvertebrates in the shredder functional feeding group increased with time since logging and canopy cover (high PC2 scores). Brook trout density and biomass was significantly greater in young, recently logged stands (high PC1 scores) and was positively related to overall macroinvertebrate abundance. In addition, three variables – trout density, invertebrate abundance and shredder abundance – successfully discriminated between streams that were less‐impacted versus more‐impacted by forestry.

4. These results indicate that timber harvest in northern New England headwater streams may shift shredder‐dominated macroinvertebrate communities supporting low trout abundance to a grazer/chironomid‐dominated macroinvertebrate community supporting higher trout abundance. However, while local effects on brook trout abundance may be positive, these benefits may be outweighed by negative effects of brook trout on co‐occurring species, as well as impairment of habitat quality downstream. Research testing the generality of these patterns will improve understanding of how aquatic ecosystems respond to anthropogenic and natural trajectories of forest change.
Long‐term prophylaxis with intermediate‐purity factor VIII concentrate (Haemate P) in a patient with type 3 von Willebrand disease and recurrent gastrointestinal bleeding
Authors: COPPOLA A. , CIMINO E. , CONCA P. , De Simone C. , TUFANO A. , TARANTINO G. , CERBONE A. M. , DI MINNO G.
Published: January 2006

Summary.  Prophylaxis with von Willebrand factor (VWF)‐containing concentrates is considered to be a potential approach for patients with von Willebrand disease (VWD) and severe bleeding tendency. We report the case of a 57‐year‐old man with type 3 VWD and a history of recurrent melaena. Bleeding frequency and severity had progressively increased and the patient showed chronic anaemia and persistent haemoglobin in the stools. Endoscopic examinations revealed multiple vascular mucosal abnormalities (MVA) of the stomach and large bowel. Photocoagulation of some actively bleeding lesions and octreotide did not significantly affect his clinical conditions: six red cell transfusions and >400 000 IU of intermediate‐purity factor VIII (FVIII) concentrate (Haemate P) on‐demand were needed during 2002. Prophylaxis with Haemate P 40 IU kg−1 (102 IU kg−1 VWF:RCo) thrice weekly was associated with improvement of his mean haemoglobin levels, cessation of clear‐cut melaena and red cell transfusions and reduction of total Haemate P requirements (−20% over 2003–04). Prophylaxis with Haemate P is still ongoing without any adverse event over a 30‐month period. Clinical course and pharmacokinetic evaluations led to administer Haemate P each 72–96 h. Possible vascular complications were excluded by a careful clinical follow up, as the patient suffered from arterial hypertension and diabetes mellitus; thrombophilic abnormalities were previously excluded and no signs of abnormal coagulation activation or FVIII:C levels >150% were detected thereafter. Long‐term prophylaxis with Haemate P has been shown to be safe, effective (also in terms of quality of life) and cost saving in this patient with severe gastrointestinal bleeding due to MVA and VWD.
Short communication: Strengthening sub‐national communicable disease surveillance in a remote Pacific Island country by adapting a successful African outbreak surveillance model
Authors: Nelesone Tekaai , Durrheim David N. , Speare Richard , Kiedrzynski Tom , Melrose Wayne D.
Published: January 2006

Successful communicable disease surveillance depends on effective bidirectional information flow between clinicians at the periphery and communicable disease control units at regional, national and global levels. Resource‐poor countries often struggle to establish and maintain the crucial link with the periphery. A simple syndrome‐based outbreak surveillance system initially developed and evaluated in Mpumalanga Province, South Africa was adapted for the Pacific island nation of Tuvalu. Eight syndromes were identified for surveillance: acute flaccid paralysis (poliomyelitis), profuse watery diarrhoea (cholera), diarrhoea outbreak, dysentery outbreak, febrile disease with abdominal symptoms and headache (typhoid), febrile disease with generalized non‐blistering rash (measles), febrile disease with intense headache and/or neck stiffness with or without haemorrhagic rash (meningococcal meningitis), and outbreaks of other febrile diseases of unknown origin. A user‐oriented manual, the Tuvalu Outbreak Manual (http://www.wepi.org/books/tom/), was developed to support introduction of the surveillance system. Nurses working in seven outer island clinics and the hospital outpatient department on the main island rapidly report suspected outbreaks and submit weekly zero‐reports to the central communicable disease control unit. An evaluation of the system after 12 months indicated that the Outbreak Manual was regarded as very useful by clinic nurses, and there was early evidence of improved surveillance and response to the disease syndromes under surveillance.
Modèle pronostique simplifié d’évaluation de la mortalité intrahospitalière globale des enfants en Afrique centrale
Authors: Bitwe Richard , Dramaix Michèle , Hennart Et Philippe
Published: January 2006

Objectifs  Cette étude a pour objectif la recherche d'un modèle simplifié de prédiction de la mortalité globale des enfants hospitalisés à Goma en Afrique centrale.

Méthodes  Les données d'une cohorte prospective de 414 enfants hospitalisés à l'hôpital provincial de Goma (HPG) du 1er Avril 2003 au 31 mars 2004 ont été analysées tant en analyse univariée qu'en analyse de régression logistique. Les OR ajustés (IC 95%) ont été calculés. Un score pronostique a été construit à partir des coefficients de régression logistique. Les performances du modèle logistique et du score ont étéétudiées par le calcul des aires sous les courbes ROC respectives.

Résultats  La mortalité globale était de 15,9%. Les indicateurs suivants: l’âge, le z‐score poids pour âge (Z‐PPA), le périmètre brachial, l’état de conscience, la raideur de la nuque, le tirage intercostal et le diagnostic infectieux, pris isolément, étaient associés au statut à la sortie. Le modèle de régression logistique ‘modèle de Goma 1’ confirme le risque de décès plus élevé pour les enfants jeunes (âge<12 mois) (OR ajusté (ic 95%): 3,5 (1,4–8,8)), en retard de croissance pondérale (−3 < z‐ppa ≤ −2 et z‐ppa ≤ −3) (OR ajustés: 3,2 (1,4–7,6) et 4,4 (1,7–11,2)) ou avec périmètre brachial bas (≥115 mm) (OR ajusté: 3,4 (1,5–7,3)), inconscients (OR ajusté 9,6 (3,1–29,9)) et présentant une septicémie (OR ajusté: 6,6 (2,1–21,1)). L'aire sous la courbe ROC du modèle pronostique simplifié est de 0,83 (0,78–0,88) et celle du score est de 0,80 (0,75–0,86).

Conclusion  Cette étude offre un modèle simplifié de prédiction de la mortalité intrahospitalière des enfants et un score pronostique basés sur les indicateurs suivants: l’âge, le Z‐PPA ou le périmètre brachial, l’état de conscience et le type d‘infection.

Ce modèle et le score pourront être utilisés pour l’évaluation du pronostic et des programmes mis en place pour réduire la mortalité intrahospitalière dans cette région.
Ciclopirox 1% shampoo for the treatment of seborrheic dermatitis
Authors: Gupta Aditya K. , Nicol Karyn A.
Published: January 2006

Seborrheic dermatitis is a chronic superficial fungal infection of the skin, particularly affecting sites rich in sebaceous glands. Although the precise etiology of seborrheic dermatitis is uncertain, yeasts of the genus Malassezia are known to play a causative role. Ciclopirox is a broad‐spectrum, hydroxypyridone‐derived, synthetic antifungal agent, which also has anti‐inflammatory properties. Ciclopirox is effective both in vitro and in vivo against Malassezia yeasts, making it a valuable option for the treatment of seborrheic dermatitis. Varying frequencies and concentrations of ciclopirox shampoo have been shown to be effective and safe in the treatment of seborrheic dermatitis of the scalp.
Dermoscopic examination of the nail bed and matrix
Authors: Hirata S. H. , Yamada S. , Almeida F. A. , Enokihara M. Y. , Rosa I. P. , Enokihara M. M. S. , Michalany N. S
Published: January 2006

Background  Dermoscopy has furthered advances in the differential diagnosis of longitudinal melanonychia; however, fewer details observed in the nail, as compared to skin lesions, make interpretation difficult.

Methods  Ten cases of longitudinal melancholia, from several etiologies, were submitted to direct dermoscopic examination of the nail bed and matrix.

Results  We observed the presence of globules, streaks, and pigment network in the nail bed and matrix, which are dermoscopic features not seen in the nail plate.

Conclusions  This procedure enables visualization of dermascopic features not seen in the nail plate, making the diagnosis of melanocytic lesions easier.
Nephrogenic fibrosing dermopathy in a patient with acute renal failure never requiring dialysis
Authors: Cassis Tamella B. , Jackson James Mark , Sonnier George B. , Callen Jeffrey P.
Published: January 2006

Nephrogenic fibrosing dermopathy (NFD) is a newly recognized cutaneous fibrosing disorder. To date the etiology, pathogenesis, and clinical course remains unknown. The majority of cases have been in renal dialysis or renal transplant patients. Only four cases have been reported in which patients had acute renal failure and never required dialysis. Currently, there is no effective treatment.

A 65‐year‐old man was hospitalized for pneumonia. During hospitalization he developed acute renal failure secondary to acute tubular necrosis. The patient had woody indurated plaques on his upper extremities and trunk, and brown indurated plaques on his trunk. Histopathological examination revealed a spindle cell proliferation infiltrating through the dermis and subcutis with mild mucin deposition.

Nephrogenic fibrosing dermopathy is a novel fibrosing disorder diagnosed clinically and histopatholigically. Currently no risk factors other than renal failure have been identified. Our patient is a unique example of NFD observed in acute renal failure secondary to acute tubular necrosis, never requiring dialysis. We also review the four other cases of acute NFD never requiring dialysis that have been reported in the literature.
Skin prick testing to food allergens in breast‐fed young infants with moderate to severe atopic dermatitis
Authors: Rennick Gordon J , Moore Elizabeth , Orchard David C
Published: January 2006

The role of food allergy in atopic dermatitis is controversial. This study presents results of skin prick tests to 31 different food allergens in a selected population of predominantly breast‐fed young infants who had moderate to severe generalized atopic dermatitis. Of the 59 infants (22 female, mean age 26.5 weeks) tested, 54 infants (91.5%) had positive responses to one or more foods, 53 infants (90%) were positive to one or more of the five common food allergens (egg white, cow's milk, peanuts, wheat or soy) and 80% were positive to egg white, which was by far the most common positive test. A total of 37 infants had strongly positive responses to one or more foods, with 33 of these 37 having strongly positive responses to egg white. The significance of these responses is discussed. It is concluded that positive skin prick tests to foods, particularly to egg white, are very common in this selected population of breast‐fed infants with moderate to severe atopic dermatitis.
Squamous cell carcinoma of the hand masquerading as a cutaneous infection
Authors: Fisher Jemima , Masson James , Rosen Robert
Published: January 2006

A 33‐year‐old male concreter presented with a small abscess on his right index finger following an injury at work. Histological examination of the lesion was consistent with chronic inflammation and Staphylococcus aureus, Streptococcus anginosus and Escherichia coli were isolated on cultures. The lesion was treated as a chronic fungal infection with bacterial superinfection. Seventeen months later, a bone scan showed periarticular involvement, and a diagnostic biopsy identified a well‐differentiated squamous cell carcinoma. He underwent amputation of his index and middle fingers. After 4 years of follow up, there has been no evidence of recurrence at the primary site, but he has since developed two further primary squamous cell carcinomas. This case emphasizes the importance of considering malignancy when dealing with chronic infections of the hand.
Epiluminescence dermatoscopy enhanced patient compliance and achieved treatment success in pseudofolliculitis barbae
Authors: Chuh Antonio , Zawar Vijay
Published: January 2006

A patient presented with recalcitrant pseudofolliculitis barbae and hypertrophic scarring. The use of epiluminescence dermatoscopy rendered clear visualization of U‐shaped ingrowing hairs corresponding to the sites of individual papules. Such real‐time demonstration led to an attitude change and good compliance with medical advice against overshaving, resulting in a successful treatment outcome.
Alopecia areata masquerading as frontal fibrosing alopecia
Authors: Kwong Rhonda A , Kossard Steven
Published: January 2006

Postmenopausal women with frontal recession may represent a diagnostic challenge, as frontal fibrosing alopecia and alopecia areata may be clinically difficult to distinguish. A 53‐year‐old postmenopausal woman presented with a progressive fronto‐temporal marginal alopecia with sparing of her eyebrows. Scalp biopsy of the affected frontal hairline revealed peribulbar lymphocytic inflammation, but no evidence of lichenoid inflammation, perifollicular fibrosis or scarring. Whereas the pathology strongly favoured alopecia areata, the clinical features overlapped with frontal fibrosing alopecia, a variant of lichen planopilaris targeting the frontal scalp. This paper presents an atypical clinical presentation of alopecia areata, which may be mistaken for frontal fibrosing alopecia.
Allergic contact dermatitis to thiourea in a neoprene knee brace
Authors: Sakata Shinichiro , Cahill Jennifer , Nixon Rosemary
Published: January 2006

An elderly woman developed an itchy, weeping, erythematous, papular eruption, confined to the skin under her neoprene knee brace. Allergic contact dermatitis to diethylthiourea and to her neoprene knee brace were diagnosed by positive patch test reactions. Allergic contact dermatitis from thioureas may be underdiagnosed, as they are not tested as part of the standard patch test series. Clinicians are encouraged to consider this diagnosis in patients with reactions to synthetic rubber, especially neoprene.