bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Hydrogen Peroxide-Producing and Hydrogen Peroxide-Consuming Peroxidases in the Leaf Apoplast of Cowpea in Manganese Tolerance
Authors: Fecht-Christoffers Marion Maria , Führs Hendrik , Braun Hans-Peter , Horst Walter Johannes
Published: February 2006

The apoplast is considered the leaf compartment decisive for manganese (Mn) toxicity and tolerance in cowpea (Vigna unguiculata). Particularly apoplastic peroxidases (PODs) were proposed to be key enzymes in Mn toxicity-induced processes. The presented work focuses on the characterization of the role of hydrogen peroxide (H2O2)-producing (NADH peroxidase) and H2O2-consuming peroxidase (guaiacol POD) in the apoplastic washing fluid (AWF) of leaves for early stages of Mn toxicity and genotypic differences in Mn tolerance of cowpea. Leaf AWF of the Mn-sensitive cultivar (cv) TVu 91 but not of the Mn-tolerant cv 1987 showed an increase of guaiacol-POD and NADH-peroxidase activities at elevated AWF Mn concentrations. two-dimensional resolutions of AWF proteins revealed that cv TVu 91 expressed more and additional proteins at high Mn treatment, whereas Mn-tolerant cv TVu 1987 remained nearly unaffected. In both cultivars, NADH-peroxidase activity and accompanied H2O2 formation rate in vitro were significantly affected by Mn2+, p-coumaric acid, and metabolites occurring in the AWF. The total phenol concentration in the AWF was indicative of advanced stages of Mn toxicity but was rather unrelated to early stages of Mn toxicity and genotypic differences in Mn tolerance. The NADH oxidation by AWF PODs was significantly delayed or enhanced in the presence of the protein-free AWF from cv TVu 1987 or cv TVu 91, respectively. High-performance liquid chromatography analysis of AWF indicates the presence of phenols in cv TVu 1987 not observed in cv TVu 91. We conclude from our studies that the H2O2-producing NADH peroxidase and its modulation by stimulating or inhibiting phenolic compounds in the leaf apoplast play a major role for Mn toxicity and Mn tolerance in cowpea.
Mutations in the NB-ARC Domain of I-2 That Impair ATP Hydrolysis Cause Autoactivation
Authors: Tameling Wladimir I.L. , Vossen Jack H. , Albrecht Mario , Lengauer Thomas , Berden Jan A. , Haring Michel A. , Cornelissen Ben J.C. , Takken Frank L.W.
Published: February 2006

Resistance (R) proteins in plants confer specificity to the innate immune system. Most R proteins have a centrally located NB-ARC (nucleotide-binding adaptor shared by APAF-1, R proteins, and CED-4) domain. For two tomato (Lycopersicon esculentum) R proteins, I-2 and Mi-1, we have previously shown that this domain acts as an ATPase module that can hydrolyze ATP in vitro. To investigate the role of nucleotide binding and hydrolysis for the function of I-2 in planta, specific mutations were introduced in conserved motifs of the NB-ARC domain. Two mutations resulted in autoactivating proteins that induce a pathogen-independent hypersensitive response upon expression in planta. These mutant forms of I-2 were found to be impaired in ATP hydrolysis, but not in ATP binding, suggesting that the ATP- rather than the ADP-bound state of I-2 is the active form that triggers defense signaling. In addition, upon ADP binding, the protein displayed an increased affinity for ADP suggestive of a change of conformation. Based on these data, we propose that the NB-ARC domain of I-2, and likely of related R proteins, functions as a molecular switch whose state (on/off) depends on the nucleotide bound (ATP/ADP).
A Reassessment of Substrate Specificity and Activation of Phytochelatin Synthases from Model Plants by Physiologically Relevant Metals
Authors: Loscos Jorge , Naya Loreto , Ramos Javier , Clemente Maria R. , Matamoros Manuel A. , Becana Manuel
Published: February 2006

Phytochelatin synthases (PCS) catalyze phytochelatin (PC) synthesis from glutathione (GSH) in the presence of certain metals. The resulting PC-metal complexes are transported into the vacuole, avoiding toxic effects on metabolism. Legumes have the unique capacity to partially or completely replace GSH by homoglutathione (hGSH) and PCs by homophytochelatins (hPCs). However, the synthesis of hPCs has received little attention. A search for PCS genes in the model legume Lotus (Lotus japonicus) resulted in the isolation of a cDNA clone encoding a protein (LjPCS1) highly homologous to a previously reported homophytochelatin synthase (hPCS) of Glycine max (GmhPCS1). Recombinant LjPCS1 and Arabidopsis (Arabidopsis thaliana) PCS1 (AtPCS1) were affinity purified and their polyhistidine-tags removed. AtPCS1 catalyzed hPC synthesis from hGSH alone at even higher rates than did LjPCS1, indicating that GmhPCS1 is not a genuine hPCS and that a low ratio of hPC to PC synthesis is an inherent feature of PCS1 enzymes. For both enzymes, hGSH is a good acceptor, but a poor donor, of γ-glutamylcysteine units. Purified AtPCS1 and LjPCS1 were activated (in decreasing order) by Cd2+, Zn2+, Cu2+, and Fe3+, but not by Co2+ or Ni2+, in the presence of 5 mm GSH and 50 μm metal ions. Activation of both enzymes by Fe3+ was proven by the complete inhibition of PC synthesis by the iron-specific chelator desferrioxamine. Plants of Arabidopsis and Lotus accumulated (h)PCs only in response to a large excess of Cu2+ and Zn2+, but to a much lower extent than did with Cd2+, indicating that (h)PC synthesis does not significantly contribute in vivo to copper, zinc, and iron detoxification.
Light-Regulated, Tissue-Specific, and Cell Differentiation-Specific Expression of the Arabidopsis Fe(III)-Chelate Reductase Gene AtFRO6
Authors: Feng Haizhong , An Fengying , Zhang Suzhi , Ji Zhendong , Ling Hong-Qing , Zuo Jianru
Published: February 2006

Iron is an essential element for almost all living organisms, actively involved in a variety of cellular activities. To acquire iron from soil, strategy I plants such as Arabidopsis (Arabidopsis thaliana) must first reduce ferric to ferrous iron by Fe(III)-chelate reductases (FROs). FRO genes display distinctive expression patterns in several plant species. However, regulation of FRO genes is not well understood. Here, we report a systematic characterization of the AtFRO6 expression during plant growth and development. AtFRO6, encoding a putative FRO, is specifically expressed in green-aerial tissues in a light-dependent manner. Analysis of mutant promoter-β-glucuronidase reporter genes in transgenic Arabidopsis plants revealed the presence of multiple light-responsive elements in the AtFRO6 promoter. These light-responsive elements may act synergistically to confer light responsiveness to the AtFRO6 promoter. Moreover, no AtFRO6 expression was detected in dedifferentiated green calli of the korrigan1-2 (kor1-2) mutant or undifferentiated calli derived from wild-type explants. Conversely, AtFRO6 is expressed in redifferentiated kor1-2 shoot-like structures and differentiating calli of wild-type explants. In addition, AtFRO7, but not AtFRO5 and AtFRO8, also shows a reduced expression level in kor1-2 green calli. These results suggest that whereas photosynthesis is necessary but not sufficient, both light and cell differentiation are necessary for AtFRO6 expression. We propose that AtFRO6 expression is light regulated in a tissue- or cell differentiation-specific manner to facilitate the acquisition of iron in response to distinctive developmental cues.
Gain-of-Function Phenotypes of Many CLAVATA3/ESR Genes, Including Four New Family Members, Correlate with Tandem Variations in the Conserved CLAVATA3/ESR Domain
Authors: Strabala Timothy J. , O'Donnell Philip J. , Smit Anne-Marie , Ampomah-Dwamena Charles , Martin E. Jane , Netzler Natalie , Nieuwenhuizen Niels J. , Quinn Brian D. , Foote Humphrey C.C. , Hudson Keith R.
Published: February 2006

Secreted peptide ligands are known to play key roles in the regulation of plant growth, development, and environmental responses. However, phenotypes for surprisingly few such genes have been identified via loss-of-function mutant screens. To begin to understand the processes regulated by the CLAVATA3 (CLV3)/ESR (CLE) ligand gene family, we took a systems approach to gene identification and gain-of-function phenotype screens in transgenic plants. We identified four new CLE family members in the Arabidopsis (Arabidopsis thaliana) genome sequence and determined their relative transcript levels in various organs. Overexpression of CLV3 and the 17 CLE genes we tested resulted in premature mortality and/or developmental timing delays in transgenic Arabidopsis plants. Overexpression of 10 CLE genes and the CLV3 positive control resulted in arrest of growth from the shoot apical meristem (SAM). Overexpression of nearly all the CLE genes and CLV3 resulted in either inhibition or stimulation of root growth. CLE4 expression reversed the SAM proliferation phenotype of a clv3 mutant to one of SAM arrest. Dwarf plants resulted from overexpression of five CLE genes. Overexpression of new family members CLE42 and CLE44 resulted in distinctive shrub-like dwarf plants lacking apical dominance. Our results indicate the capacity for functional redundancy of many of the CLE ligands. Additionally, overexpression phenotypes of various CLE family members suggest roles in organ size regulation, apical dominance, and root growth. Similarities among overexpression phenotypes of many CLE genes correlate with similarities in their CLE domain sequences, suggesting that the CLE domain is responsible for interaction with cognate receptors.
Ethylene Modulates Flavonoid Accumulation and Gravitropic Responses in Roots of Arabidopsis
Authors: Buer Charles S. , Sukumar Poornima , Muday Gloria K.
Published: February 2006

Plant organs change their growth direction in response to reorientation relative to the gravity vector. We explored the role of ethylene in Arabidopsis (Arabidopsis thaliana) root gravitropism. Treatment of wild-type Columbia seedlings with the ethylene precursor 1-aminocyclopropane carboxylic acid (ACC) reduced root elongation and gravitropic curvature. The ethylene-insensitive mutants ein2-5 and etr1-3 had wild-type root gravity responses, but lacked the growth and gravity inhibition by ACC found in the wild type. We examined the effect of ACC on tt4(2YY6) seedlings, which have a null mutation in the gene encoding chalcone synthase, the first enzyme in flavonoid synthesis. The tt4(2YY6) mutant makes no flavonoids, has elevated indole-3-acetic acid transport, and exhibits a delayed gravity response. Roots of tt4(2YY6), the backcrossed line tt4-2, and two other tt4 alleles had wild-type sensitivity to growth inhibition by ACC, whereas the root gravitropic curvature of these tt4 alleles was much less inhibited by ACC than wild-type roots, suggesting that ACC may reduce gravitropic curvature by altering flavonoid synthesis. ACC treatment induced flavonoid accumulation in root tips, as judged by a dye that becomes fluorescent upon binding flavonoids in wild type, but not in ein2-5 and etr1-3. ACC also prevented a transient peak in flavonoid synthesis in response to gravity. Together, these experiments suggest that elevated ethylene levels negatively regulate root gravitropism, using EIN2- and ETR1-dependent pathways, and that ACC inhibition of gravity response occurs through altering flavonoid synthesis.
Defective Long-Distance Auxin Transport Regulation in the Medicago truncatula super numeric nodules Mutant
Authors: van Noorden Giel E. , Ross John J. , Reid James B. , Rolfe Barry G. , Mathesius Ulrike
Published: February 2006

Long-distance auxin transport was examined in Medicago truncatula and in its supernodulating mutant sunn (super numeric nodules) to investigate the regulation of auxin transport during autoregulation of nodulation (AON). A method was developed to monitor the transport of auxin from the shoot to the root in whole seedlings. Subsequently, the transport was monitored after inoculation of roots with the nodulating symbiont Sinorhizobium meliloti. The sunn mutant showed an increased amount of auxin transported from the shoot to the root compared to the wild type. The auxin transport capacity of excised root segments was similar in wild type and sunn, suggesting that the difference in long-distance auxin transfer between them is due to loading in the shoot. After inoculation, wild-type seedlings showed decreased auxin loading from the shoot to the root; however, the sunn mutant failed to reduce the amount of auxin loaded. The time of reduced auxin loading correlated with the onset of AON. Quantification of endogenous auxin levels at the site of nodule initiation showed that sunn contained three times more auxin than wild type. Inoculation of sunn failed to reduce the level of auxin within 24 h, as was observed in the wild type. We propose a model for the role of auxin during AON of indeterminate legumes: 1) high levels of endogenous auxin are correlated with increased numbers of nodules, 2) inoculation of roots reduces auxin loading from the shoot to the root, and 3) subsequent reduction of auxin levels in the root inhibits further nodule initiation.
A Transcriptome-Based Characterization of Habituation in Plant Tissue Culture
Authors: Pischke Melissa S. , Huttlin Edward L. , Hegeman Adrian D. , Sussman Michael R.
Published: February 2006

For the last 50 years, scientists have recognized that varying ratios of the plant hormones cytokinin and auxin induce plant cells to form particular tissues: undifferentiated calli, shoot structures, root structures, or a whole plant. Proliferation of undifferentiated callus tissue, greening, and the formation of shoot structures are all cytokinin-dependent processes. Habituation refers to a naturally occurring phenomenon whereby callus cultures, upon continued passage, lose their requirement for cytokinin. Earlier studies of calli with a higher-than-normal cytokinin content indicate that overproduction of cytokinin by the culture tissues is a possible explanation for this acquired cytokinin independence. A transcriptome-based analysis of a well established habituated Arabidopsis (Arabidopsis thaliana) cell culture line was undertaken, to explore genome-wide expression changes underlying the phenomenon of habituation. Increased levels of expression of the cytokinin receptor CRE1, as well as altered levels of expression of several other genes involved in cytokinin signaling, indicated that naturally acquired deregulation of cytokinin-signaling components could play a previously unrecognized role in habituation. Up-regulation of several cytokinin oxidases, down-regulation of several known cytokinin-inducible genes, and a lack of regulation of the cytokinin synthases indicated that increases in hormone concentration may not be required for habituation. In addition, up-regulation of the homeodomain transcription factor FWA, transposon-related elements, and several DNA- and chromatin-modifying enzymes indicated that epigenetic changes contribute to the acquisition of cytokinin habituation.
Cytoplasmic Male Sterility of Rice with Boro II Cytoplasm Is Caused by a Cytotoxic Peptide and Is Restored by Two Related PPR Motif Genes via Distinct Modes of mRNA Silencing
Authors: Wang Zhonghua , Zou Yanjiao , Li Xiaoyu , Zhang Qunyu , Chen Letian , Wu Hao , Su Dihua , Chen Yuanling , Guo Jingxin , Luo Da , Long Yunming , Zhong Yang , Liu Yao-Guang
Published: February 2006

Cytoplasmic male sterility (CMS) and nucleus-controlled fertility restoration are widespread plant reproductive features that provide useful tools to exploit heterosis in crops. However, the molecular mechanism underlying this kind of cytoplasmic–nuclear interaction remains unclear. Here, we show in rice (Oryza sativa) with Boro II cytoplasm that an abnormal mitochondrial open reading frame, orf79, is cotranscribed with a duplicated atp6 (B-atp6) gene and encodes a cytotoxic peptide. Expression of orf79 in CMS lines and transgenic rice plants caused gametophytic male sterility. Immunoblot analysis showed that the ORF79 protein accumulates specifically in microspores. Two fertility restorer genes, Rf1a and Rf1b, were identified at the classical locus Rf-1 as members of a multigene cluster that encode pentatricopeptide repeat proteins. RF1A and RF1B are both targeted to mitochondria and can restore male fertility by blocking ORF79 production via endonucleolytic cleavage (RF1A) or degradation (RF1B) of dicistronic B-atp6/orf79 mRNA. In the presence of both restorers, RF1A was epistatic over RF1B in the mRNA processing. We have also shown that RF1A plays an additional role in promoting the editing of atp6 mRNAs, independent of its cleavage function.
TheArabidopsisAux/IAA Protein Family Has Diversified in Degradation and Auxin Responsiveness
Authors: Dreher Kate A. , Brown Jessica , Saw Robert E. , Callis Judy
Published: February 2006

Rapid, auxin-responsive degradation of multiple auxin/indole-3-acetic acid (Aux/IAA) proteins is essential for plant growth and development. Domain II residues were previously shown to be required for the degradation of several Arabidopsis thaliana Aux/IAA proteins. We examined the degradation of additional full-length family members and the proteolytic importance of N-terminal residues outside domain II using luciferase (LUC) fusions. Elimination of domain I did not affect degradation. However, substituting an Arg for a conserved Lys between domains I and II specifically impaired basal degradation without compromising the auxin-mediated acceleration of degradation. IAA8, IAA9, and IAA28 contain domain II and a conserved Lys, but they were degraded more slowly than previously characterized family members when expressed as LUC fusions, suggesting that sequences outside domain II influence proteolysis. We analyzed the degradation of IAA31, with a region somewhat similar to domain II but without the conserved Lys, and of IAA20, which lacks domain II and the conserved Lys. Both IAA20:LUC and epitope-tagged IAA20 were long-lived, and their longevity was not influenced by auxin. Epitope-tagged IAA31 was long-lived, like IAA20, but by contrast, it showed accelerated degradation in response to auxin. The existence of long-lived and auxin-insensitive Aux/IAA proteins suggeststhat they may play a novel role in auxin signaling.
Arabidopsis GLUTAMINE-RICH PROTEIN23Is Essential for Early Embryogenesis and Encodes a Novel Nuclear PPR Motif Protein That Interacts with RNA Polymerase II Subunit III
Authors: Ding Yong-He , Liu Nai-You , Tang Zuo-Shun , Liu Jie , Yang Wei-Cai
Published: February 2006

Precise control of gene expression is critical for embryo development in both animals and plants. We report that Arabidopsis thaliana  GLUTAMINE-RICH PROTEIN23 (GRP23) is a pentatricopeptide repeat (PPR) protein that functions as a potential regulator of gene expression during early embryogenesis in Arabidopsis. Loss-of-function mutations of GRP23 caused the arrest of early embryo development. The vast majority of the mutant embryos arrested before the 16-cell dermatogen stage, and none of the grp23 embryos reached the heart stage. In addition, 19% of the mutant embryos displayed aberrant cell division patterns. GRP23 encodes a polypeptide with a Leu zipper domain, nine PPRs at the N terminus, and a Gln-rich C-terminal domain with an unusual WQQ repeat. GRP23 is a nuclear protein that physically interacts with RNA polymerase II subunit III in both yeast and plant cells. GRP23 is expressed in developing embryos up to the heart stage, as revealed by β-glucuronidase reporter gene expression and RNA in situ hybridization. Together, our data suggest that GRP23, by interaction with RNA polymerase II, likely functions as a transcriptional regulator essential for early embryogenesis in Arabidopsis.
Ultrastructural morphology suggesting a new hypothesis for development of microsporidians seen in Loma salmonae infecting the gills of rainbow and brook trout
Authors: Lovy J. , Wright G. M. , Wadowska D. W. , Speare D. J.
Published: February 2006

In two variants of Loma salmonae that have specificity for rainbow trout Oncorhynchus mykiss(OA variant) and specificity to brook trout Salvelinus fontinalis(SV variant), the parasitophorous vacuole forms at the onset of sporogony. In the OA variant the merogonial stage is bound by a single plasma membrane in direct contact with host cytoplasm. The parasitophorous vacuole formation is initiated by the host cell surrounding the merogonial stages with endoplasmic reticulum (ER) as occurs in autophagy. Of the two host ER membranes surrounding the parasite, one remains in close association with the plasma membrane of the meront, while the other forms the limiting membrane of the vacuole. The sporogonial stage is bounded by two closely apposed membranes, giving the appearance of a thick electron dense plasmalemma. The observations from this study support the novel hypothesis that this microsporidian uses the intracellular process of autophagy to aid formation of a parasitophorous vacuole. The morphology of the SV‐variant is consistent with that of the OA‐variant suggesting that it uses the same mechanism for development.
Atlantic hagfish exploit prey captured by other taxa
Authors: Auster P. J. , Barber K.
Published: February 2006

Observations of Atlantic hagfish Myxine glutinosa exploiting prey captured, but not fully consumed, by the horse star Hippasteria phrygiana and Jonah crab Cancer borealis are described. Such interactions are defined as encounter competition. These represent the first reported observations of this type of interspecific interaction for Atlantic hagfish.
Retention of visible implant and visible implant elastomer tags in brown trout in an English chalk stream
Authors: Summers D. W. , Roberts D. E. , Giles N. , Stubbing D. N.
Published: February 2006

Retention of both rigid and new soft standard size visible implant (VI) tags in brown trout Salmo trutta after 6 months varied between 42 and 97% for different batches, with no evidence of increased retention of the new type of tag. The 6 month retention of visible implant elastomer tags (VIE) also varied but with a mean of 96%. The VIE retention gradually declined with time up to 42 months.
Early development of the chondrocranium in Salmo letnica(Karaman, 1924)(Teleostei: Salmonidae)
Authors: Ristovska M. , Karaman B. , Verraes W. , Adriaens D.
Published: February 2006

The ontogenetic development of the chondrocranium of Ohrid trout Salmo letnica was studied from hatching until 92 days post‐hatching (dph). Most of the samples were in toto trypsin cleared and stained, some specimens were used for serial histological sectioning. The serial histological sections of fish specimens at the age of 92 dph were used for a graphical reconstruction of the cartilaginous neurocranium. A chronological evaluation of the formation of the cartilaginous skull in the early development of S. letnica was performed. In order to investigate to what degree the ontogeny of the Ohrid trout is unique, the results were compared with data of the development of other salmonids, as well as some non‐salmonid teleosts. The development of the cartilaginous structures of the Ohrid trout was found to be similar to that of other salmonids. Most of the cartilage structures of the neurocranium and the viscerocranium are present at the moment of hatching of this species. A fully developed chondrocranium was observed at the age of 92 dph, when the first signs of cartilage resorption could also be observed.
Contact allergy in patients with chronic venous leg ulcers – possible role of chronic venous insufficiency
Authors: Zmudzinska Maria , Czarnecka‐Operacz Magdalena , Silny Wojciech , Kramer Lucyna
Published: February 2006

The purpose of this study was to evaluate frequency of contact allergy in patients with chronic venous leg ulcers (CVLU) and to estimate possible relationships between allergic contact reactions and characteristics of both chronic venous insufficiency (CVI) and CVLU. We performed patch tests with the European standard series, antibiotics, glucocorticosteroids and ointment vehicles in 50 patients with CVLU. Patients underwent detailed CVI diagnostics using colour flow duplex ultrasound examination, ankle brachial pressure index determination and leg ulcers area measurement. Positive patch tests results were found in 80% and polyvalent allergy in 56% of patients. Statistically significant correlations were recorded between CVI and CVLU duration, CVLU duration and CVLU area and between CVI duration and polyvalent allergy frequency. Statistically significant differences were observed between coexistence of superficial and deep system insufficiency and CVLU duration, characteristics of contact allergic reactions and CVI duration, frequency of allergic contact reaction and presence or absence of long saphenous vein insufficiency, incidences of vein thrombosis and characteristics of contact allergic reactions as well as between characteristics of contact allergic reactions and both CVLU duration and area. Complex pathophysiological processes, including inflammatory reactions, in course of CVI may influence development of allergic contact reaction in CVLU patients.
Fatty acids in serum cholesteryl esters in relation to asthma and lung function in children
Authors: Bolte G. , Kompauer I. , Fobker M. , Cullen P. , Keil U. , von Mutius E. , Weiland S. K.
Published: February 2006

Background
Dietary fatty acid intake has been proposed to contribute to asthma development with n‐6 polyunsaturated fatty acids (PUFA) having a detrimental and n‐3 PUFA a protective effect.

Objective
The aim of our analysis was to explore the relationship between fatty acid composition of serum cholesteryl esters as marker of dietary intake and prevalence of asthma, impaired lung function and bronchial hyper‐responsiveness in children.

Methods
The study population consisted of 242 girls and 284 boys aged 8–11 years, living in Munich, Germany. Data were collected by parental questionnaire, lung function measurement and skin prick test according to the International Study of Asthma and Allergies in Childhood phase II protocol. Confounder‐adjusted odds ratios (OR) with 95% confidence intervals (CI) were calculated for the association between quartiles of fatty acid concentration and health outcomes with the first quartile as reference.

Results
n‐3 PUFA: levels of eicosapentaenoic acid were not related to asthma and impaired lung function. Linolenic acid levels were positively associated with current asthma (OR for fourth quartile 3.35, 95% CI 1.29–8.66). Forced expiratory volume in 1 s (FEV1) values decreased with increasing levels of linolenic acid (p for trend=0.057). n‐6 PUFA: there was a strong positive association between arachidonic acid levels and current asthma (OR4th quartile 4.54, 1.77–11.62) and a negative association with FEV1 (P=0.036). In contrast, linoleic acid was negatively related to current asthma (OR4th quartile 0.34, 0.14–0.87) and FEV1 values increased with increasing levels of linoleic acid (P=0.022). The ratio of measured n‐6 to n‐3 PUFA as well as levels of palmitic and oleic acid were not consistently related to asthma or lung function.

Conclusion
Our data do not support the hypothesis of a protective role of n‐3 PUFA. Elevated arachidonic acid levels in children with asthma may be because of a disturbed balance in the metabolism of n‐6 PUFA or may be secondary to inflammation in these patients.
Influence of short‐term exposure to airborne Der p 1 and volatile organic compounds on skin barrier function and dermal blood flow in patients with atopic eczema and healthy individuals
Authors: Huss‐Marp J. , Eberlein‐König B. , Breuer K. , Mair S. , Ansel A. , Darsow U. , Krämer U. , Mayer E. , Ring J. , Behrendt H.
Published: February 2006

Background
Epidemiological studies indicate environmental pollutants to be involved in the increase in the prevalence of allergic diseases. In human exposure studies, volatile organic compounds (VOCs) have been shown to cause exacerbations of allergic asthma whereas, no data concerning atopic eczema (AE) are available.

Objective
We investigated the effect of airborne VOCs on the skin of patients with AE and controls in the presence or absence of house dust mite allergen, Der p 1.

Methods
In a double‐blind crossover study, 12 adults with AE and 12 matched healthy volunteers were exposed on their forearms to Der p 1 and subsequently to a mixture of 22 VOCs (M22, 5 mg/m3) in a total body exposure chamber for 4 h. Transepidermal water loss (TEWL) and skin blood flow were measured in all subjects before, during and after exposure. Additionally, an atopy patch test (APT) with Der p 1 was applied to the skin after exposure.

Results
A significant increase in transepidermal water loss was observed 48 h after exposure to VOCs as compared with exposure with filtered air in all individuals (mean difference: +34%; 95% Confidence Interval: 7–69%). Prior Der p 1 exposure resulted in a significant rise of dermal blood flow after 48 h in patients with AE but not in controls. Six out of seven patients showed enhanced atopy patch test (APT) reactions to HDM allergen after previous exposure to VOCs.

Conclusion
Our results show that exposure to VOCs – at concentrations commonly found in indoor environments – can damage the epidermal barrier and enhance the adverse effect of Der p 1 on sensitized subjects with AE. These findings may contribute to a better understanding of the mechanisms underlying the increase in prevalence and exacerbation of AE.
The effect of genotype and culture medium on somatic embryogenesis and plant regeneration from mature embryos of fourteen apomictic cultivars of buffel grass (Cenchrus ciliaris L.)
Authors: Colomba E. L. , Grunberg K. , Griffa S. , Ribotta A. , Mroginski L. , Biderbost E.
Published: February 2006

Buffel grass (Cenchrus ciliaris L.) is an important apomictic grass used as forage for ruminant livestock. Biotechnological methods provide opportunities for producing new germplasm. Mature embryos of fourteen buffel grass apomictic cultivars (2n = 4x = 36) were used to induce embryogenic callus formation using a basal medium supplemented with 3% sucrose and with the testing of five concentrations of 2,4‐dichlorophenoxyacetic acid (2,4‐D) and four concentrations of 6‐benzylaminopurine (BAP). The effects of cultivar and culture medium on callus induction and plant regeneration were evaluated. Significant differences were observed among the fourteen cultivars and the five concentrations of 2,4‐D (P < 0·01). Values for embryogenic callus production varied from 0 to 86·7. Most cultivars showed the highest level of embryogenic callus production on the medium with the concentration of 3 mg L−1 2,4‐D. The addition of different BAP concentrations in combination with 2,4‐D in the medium inhibited embryogenic callus growth and did not permit plant regeneration. The data clearly demonstrated that the genotype and concentrations of 2,4‐D had significant effects both on the frequency of embryonic callus formation from mature embryos and on the subsequent efficiency of plant regeneration of apomictic cultivars of buffel grass. Cultivars Biloela and Nunbank showed the greatest efficiency in in vitro culture response.
The infection of Festuca rubra subsp. pruinosa by Epichloë festucae
Authors: Zabalgogeazcoa I. , Romo M. , Keck E. , Vázquez de Aldana B. R. , García Ciudad A. , García Criado B.
Published: February 2006

Festuca rubra subsp. pruinosa is a grass that inhabits the sea cliffs of the Atlantic coasts of Europe. Four populations of this plant in the northern coast of Galicia, in northern Spain, were analysed for the presence of fungal endophytes. Of the plants included in the study, on average 0·69 were infected by an intercellular fungal endophyte. Using morphological and molecular characters, this endophyte was identified as Epichloë festucae, a clavicipitaceous, seed‐transmitted species. A half‐sibling line, consisting of endophyte‐free and endophyte‐infected plants, was developed and used to test whether the presence of the fungus affected the response of the plants to salinity. Dry weights of infected or uninfected plants, watered with sea‐water solutions or tap water, did not significantly differ.
Influence of human menopausal gonadotrophin treatment on testicular blood flow and on seminal plasma nitric oxide levels in infertile males1
Authors: Matteo M. , Cicinelli E. , Baldini D. , Cho Y. S. , Ignarro L. J. , Vitarelli A. , Boffoli D. , Greco P.
Published: February 2006

Gonadotrophin treatment is capable of increasing intratesticular blood flow and improving sperm fertilization potential. A nitric oxide (NO)‐mediated mechanism may play a role. This study aimed at evaluating whether the increase in intratesticular blood flow, in response to human menopausal gonadotrophin (hMG) treatment, is accompanied by an increase in seminal plasma NO levels in 20 normogonadotropic males affected by severe oligoasthenoteratozoospermia. Patients received 150 IU of hMG, three times a week for 3 months. Before starting treatment and at month 3 of therapy, levels of NO in the seminal plasma were determined, followed by ultrasound scanning of testis, Doppler evaluation of intratesticular vascular resistance, serum hormone and conventional semen evaluation. Statistical analysis was performed by using Wilcoxon test; the limit of statistical significance was p < 0.05. At the end of treatment, seminal plasma concentration of NO, conventional semen parameters and testicular volume did not increase significantly. Follicle‐stimulating hormone serum level significantly increased (p = 0.014) after treatment, whereas luteinizing hormone, testosterone and oestradiol values did not change. The resistance index of both intratesticular arteries significantly decreased (p = 0.012 and 0.005 for right and left testes respectively). The results of this study confirmed the positive effect of exogenous hMG on testicular blood flow, but failed to demonstrate any effect of hMG treatment on NO levels in the seminal plasma in infertile males.
Crystallography of dispersed liquid crystalline phases studied by cryo‐transmission electron microscopy
Authors: SAGALOWICZ L. , MICHEL M. , ADRIAN M. , FROSSARD P. , ROUVET M. , WATZKE H. J. , YAGHMUR A. , DE CAMPO L. , GLATTER O. , LESER M. E.
Published: February 2006

Low molecular weight surfactants, for example monoglycerides and phospholipids, form a multitude of self‐assembled structures, such as inverted cubic or hexagonal mesophases, if brought into contact with water/oil. These mesophases can be dispersed in water using adequate surface‐active materials such as low molecular weight surfactants or surface active polymers. In order to use such mesophase particles for incorporating drugs and aromas, it is essential to determine their internal crystallographic structure and to understand their mechanism of stabilization. Cryo‐transmission electron microscopy was used to investigate the internal structure of different dispersed particles at various temperatures and oil contents. It is shown here that cryo‐transmission electron microscopy, in combination with fast Fourier transform and tilting experiments, is effective in obtaining information on crystallographic structure, space group and morphology of particles with reversed bicontinuous cubic and hexagonal structures. In particular, using the presence or the absence of the {111} reflections and viewing the same particle under different axes of observation allows one to discriminate between the Im3m and Pn3m space groups. A major advantage of cryo‐transmission electron microscopy is the ability to analyse single particles. This allows the identification of particles present at very low concentrations and the coexistence of particles with different internal self‐assembly structures. With this technique we have obtained strong evidence for the presence of two cubic internal self‐assembly structures with different space groups within the same dispersion. In addition, we found that cryo‐transmission electron microscopy combined with tilting experiments enables the analysis of internal particle morphology, allowing the discussion of mechanisms for hexosome stabilization.
A new experimental procedure to quantify annular dark field images in scanning transmission electron microscopy
Authors: WALTHER T.
Published: February 2006

A new procedure to quantify the contrast in annular dark field images recorded without lattice resolution in a scanning transmission electron microscope is proposed. The method relies on the use of an in‐column energy filter prior to the annular dark field detector and the acquisition of a series of energy‐filtered images as a function of the inner detection angle. When the image contrast of an interface between two materials in such energy‐filtered annular dark field images is plotted vs. camera length and extrapolated to zero (i.e. infinite scattering angle), the contrast is shown to behave exactly as predicted by Rutherford's scattering formula (i.e. intensity scales ∝Z2). This can then be used to determine the local chemistry at and the effective chemical widths of interfaces or thin films without any additional spectroscopy method for calibration, provided the global chemical composition is known. As examples, the systems SiGe/Si and InGaAs/Ge are considered in detail.
Association between childhood sleep problems and perinatal factors, parental mental distress and behavioral problems
Authors: SHANG CHI‐YUNG , GAU SUSAN SHUR‐FEN , SOONG WEI‐TSUEN
Published: February 2006

The aim of this study was to examine the effect of age, gender and perinatal risk factors on the risks for sleep problems, and investigate the relation between childhood sleep problems and children's behavioral syndromes and parental mental distress in early and middle childhood. We recruited a representative sample of 1391 children, ages 4–9, from nine kindergartens and three elementary schools by using a multistage sampling method. Parents of child participants completed a questionnaire including perinatal risk factors, sleep habits and problems, the Child Behavior Checklist (CBCL) and the Chinese Health Questionnaire (CHQ). A mixed model was used for data analysis to address cluster effect from the same classes and schools. Results showed that boys suffered from more sleep problems than girls. Early insomnia, sleep terrors and enuresis decreased with ages, but sleepwalking increased with ages. Perinatal exposure to alcohol, coffee and non‐prescribed medication, vaginal bleeding, artificial delivery, first‐born order and higher parental CHQ score (≥4) were significantly associated with several childhood sleep problems. In addition, children with sleep problems had higher T‐scores of the eight behavioral syndromes derived from the CBCL. Our findings indicated that the childhood sleep problems were associated with perinatal risk factors, parental psychopathology and children's behavioral problems.
Population structure and inbreeding in a rare and declining bumblebee, Bombus muscorum (Hymenoptera: Apidae)
Authors: DARVILL B. , ELLIS J. S. , LYE G. C. , GOULSON D.
Published: February 2006

Owing to habitat loss populations of many organisms have declined and become fragmented. Vertebrate conservation strategies routinely consider genetic factors, but their importance in invertebrate populations is poorly understood. Bumblebees are important pollinators, and many species have undergone dramatic declines. As monoandrous social hymenopterans they may be particularly susceptible to inbreeding due to low effective population sizes. We study fragmented populations of a bumblebee species, on a model island system, and on mainland Great Britain where it is rare and declining. We use microsatellites to study: population genetic structuring and gene flow; the relationships between genetic diversity, population size and isolation; and frequencies of (sterile) diploid males — an indicator of inbreeding. We find significant genetic structuring (θ = 0.12) and isolation by distance. Populations > 10 km apart are all significantly differentiated, both on oceanic islands and on the mainland. Genetic diversity is reduced relative to closely related common species, and isolated populations exhibit further reductions. Of 16 populations, 10 show recent bottlenecking, and 3 show diploid male production. These results suggest that surviving populations of this rare insect suffer from inbreeding as a result of geographical isolation. Implications for the conservation of social hymenopterans are discussed.
Solvency, Capital Allocation, and Fair Rate of Return in Insurance
Authors: Sherris Michael
Published: February 2006

Abstract

In this article, we consider the links between solvency, capital allocation, and fair rate of return in insurance. A method to allocate capital in insurance to lines of business is developed based on an economic definition of solvency and the market value of the insurer balance sheet. Solvency, and its financial impact, is determined by the value of the insolvency exchange option. The allocation of capital is determined using a complete markets’ arbitrage‐free model and, as a result, has desirable properties, such as the allocated capital “adds up” and is consistent with the economic value of the balance sheet assets and liabilities. A single‐period discrete‐state model example is used to illustrate the results. The impact of adding lines of business is briefly considered.
Cutaneous manifestations of Hodgkin's disease
Authors: Rubenstein Melissa , Duvic Madeleine
Published: February 2006

Background  Cutaneous manifestations associated with Hodgkin's Disease (HD) have not been well described. Most existing studies of the cutaneous manifestations of HD are individual case reports or literature reviews. The goal of this study was to define the spectrum of cutaneous manifestations of HD, as observed by the consulting dermatologist at a cancer center.

Methods  The tumor registry database maintained by the Department of Medical Informatics and the M.D. Anderson Visits database over a 5‐year period was searched to identify patients with a diagnosis of HD and an appointment with Dermatology. The medical records were reviewed to determine frequency and presentation of cutaneous findings in HD.

Results  The search identified a total of 1049 registered patients with HD, of which 88 were seen at the Dermatology Clinic. Of these 88 patients evaluated by dermatology, 47 patients had either paraneoplastic cutaneous manifestations associated with HD (n = 45) or cutaneous HD (n = 3). The most common paraneoplastic skin manifestations were eczema (n = 18) and pruritis (n = 17), mycosis fungoides (n = 11), and erythema nodosum (n = 3). Mycosis fungoides, observed in 1% of the patients with HD at MDACC, was more than 290 times more common in patients with HD than in the general population.

Conclusion  Although pruritis is the most commonly recognized presenting symptom of Hodgkin's lymphoma, new onset of eczema should also be considered as a possible warning sign deserving further investigation. Patients with adult‐onset pruritus or eczema should be evaluated for possible HD with full lymph‐node exam, CBC with differential, and chest X‐ray. Erythema nodosum and mycosis fungoides should also be considered as cutaneous manifestations of HD.
Changing outcomes for children requiring intensive care following hematopoietic stem cell transplantation
Authors: Kache Saraswati , Weiss Irwin K. , Moore Theodore B.
Published: February 2006

Abstract: Past literature has shown that respiratory failure following hematopoietic stem cell transplant is associated with a universally poor outcome with mortality rates approaching 100%. More recent studies have suggested that patient survival is improving. We report our experience with the patients from our institution, a large children's hospital, who were admitted to the intensive care unit (ICU). Medical records of 183 patients, who received a bone marrow transplant between 1992 and early 2004, who were <20 yr of age, were retrospectively reviewed. Various factors that might influence mortality were examined. Over the course of the study, the ICU survival increased from 18% during the period 1992–1999 to 59% between 2000 and early 2004. In the latter period, 54% of the patients discharged from the ICU were alive at 100 days post‐transplant. Factors that were significant predictors of poor outcome were malignancy as the reason for transplant, dialysis during the ICU stay, or extreme respiratory failure with a ratio of arterial oxygen tension (PaO2)/inspired oxygen concentration (FiO2) <300. Analysis of patients who required a high positive end‐expiratory pressure or were ventilated with permissive hypercapnia showed that they also had a higher mortality. The impact on survival of factors such as age at time of transplant, graft‐vs.‐host disease, pneumonia, bacteremia, sepsis, post‐transplant days, Pediatric Risk of Mortality III score, engraftment status, or veno‐occlusive disease did not reach statistical significance in this cohort. Survival has improved for children who require intensive care following a bone marrow transplant, even for those who require mechanical ventilation. Patients with extreme respiratory failure and those requiring dialysis continue to have poor outcome. Because of an overall improvement in survival, children whose condition following transplant requires intensive care should be treated aggressively.
Post‐transplantation lymphoproliferative disorders localizing to the gastrointestinal tract after liver transplantation: Report of five pediatric cases
Authors: Lai Yi‐Chun , Ni Yen‐Hsuan , Jou Shiann‐Tarng , Ho Ming‐Chih , Wu Jia‐Feng , Chen Huey‐Ling , Hu Rey‐Heng , Jeng Yung‐Ming , Chang Mei‐Hwei , Lee Po‐Huang
Published: February 2006

Abstract: Post‐transplantation lymphoproliferative disorder (PTLD) is a life‐threatening complication of organ transplantation. PTLD can occur in every kind of organ transplantation. From July 1992 to July 2004, five patients were diagnosed at our transplantation center with PTLD after pediatric liver transplantation. During this period, there were 52 pediatric patients (<18 yr) receiving an orthotopic liver transplantation (OLT) at our center. All five patients had transmural gastrointestinal (GI) PTLD, which occurred mostly in the stomach and duodenum. Epstein–Barr virus (EBV) in situ was demonstrated in each case. EBV viral load was noted to be an important risk factor. Treatment included dose reduction of immunosuppressants and anti‐CD20 antibody infusion. Chemotherapy, including cyclophosphamide, doxorubicin, vincristine, and prednisolone, was given to three patients. Four patients have survived more than 10 months until now after treatment. The one who was unresponsive to chemotherapy and anti‐CD20 antibody had diffuse metastasis and died of systemic candidiasis. In our series, each PTLD involved the GI tract. The mechanism of this phenomenon is unclear, but these five cases indicate the high incidence of PTLD in pediatric solid organ transplantation.
Pediatric liver transplantation using left hepatic segments from living related donors: Surgical experience in 100 recipients at Saint‐Luc University Clinics
Authors: Darwish Ahmed A. , Bourdeaux Christophe , Kader Hesham A. , Janssen Magda , Sokal Etienne , Lerut Jan , Ciccarelli Olga , Veyckemans Francis , Otte Jean‐Bernard , Goyet Jean de Ville de , Reding Raymond
Published: February 2006

Abstract: Living‐related liver transplantation was developed in the context of deceased donor organ shortage, which is particularly acute for pediatric recipients. This retrospective study analyzes the surgical technique and complications in the first 100 pediatric liver transplantation using left segmental liver grafts from living donors, performed at Saint‐Luc University Clinics between July 1993 and April 2002. Pre‐operative evaluation in donors and recipients, analysis of the surgical technique, and postoperative complications were reviewed. After a median follow‐up period of 2526 days, no donor mortality was encountered, with a minimal morbidity and no long‐term sequelae. At one and five yr post‐transplantation, the actuarial patient survival rates were 94% and 92%, the corresponding figures being 92% and 89% for graft survival. The incidences of portal vein and hepatic artery thromboses, and of biliary complications were 14%, 1%, and 27%, respectively. Living‐related liver transplantation in children constitutes an efficient therapy for liver failure to face the increased demand for liver grafts. Donor morbidity was kept to acceptable incidence, and surgical technique in the recipient needs to be tailored to minimize postoperative complications.