bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chloroplasts as a Nitric Oxide Cellular Source. Effect of Reactive Nitrogen Species on Chloroplastic Lipids and Proteins
Authors: Jasid Sebastián , Simontacchi Marcela , Bartoli Carlos G. , Puntarulo Susana 
Published: September 2006

Abstract
Nitric oxide (NO) generation by soybean (Glycine max var. ADM 4800) chloroplasts was studied as an endogenous product assessed by the electron paramagnetic resonance spin-trapping technique. Nitrite and l-arginine (Arg) are substrates for enzymatic activities considered to be the possible sources of NO in plants. Soybean chloroplasts showed a NO production of 3.2 ± 0.2 nmol min−1 mg−1 protein in the presence of 1 mm NaNO2. Inhibition of photosynthetic electron flow by 3-(3,4-dichlorophenyl)-1,1-dimethyl urea resulted in a lower rate (1.21 ± 0.04 nmol min−1 mg−1 protein) of NO generation. Chloroplasts incubated with 1 mm Arg showed NO production of 0.76 ± 0.04 nmol min−1 mg−1 protein that was not affected either by omission of Ca2+ or by supplementation with Ca2+ and calmodulin to the incubation medium. This production was inhibited when chloroplasts were incubated in the presence of NO synthase inhibitors N ω-nitro-l-Arg methyl ester hydrochloride and N ω-nitro-l-Arg. In vitro exposure of chloroplasts to an NO donor (250 μ m S-nitrosoglutathione) decreased lipid radical content in membranes by 29%; however, incubation in the presence of 25 μ m peroxynitrite (ONOO−) led to an increase in lipid-derived radicals (34%). The effect of ONOO− on protein oxidation was determined by western blotting, showing an increase in carbonyl content either in stroma or thylakoid proteins as compared to controls. Moreover, ONOO− treatment significantly affected both O2 evolution and chlorophyll fluorescence in thylakoids. Data reported here suggest that NO is an endogenous metabolite in soybean chloroplasts and that reactive nitrogen species could exert either antioxidant or prooxidant effects on chloroplast macromolecules.
Carotenoid Cleavage Dioxygenase (CmCCD4a) Contributes to White Color Formation in Chrysanthemum Petals
Authors: Ohmiya Akemi , Kishimoto Sanae , Aida Ryutaro , Yoshioka Satoshi , Sumitomo Katsuhiko 
Published: September 2006

AbstractThe white petals of chrysanthemum (Chrysanthemum morifolium Ramat.) are believed to contain a factor that inhibits the accumulation of carotenoids. To find this factor, we performed polymerase chain reaction-Select subtraction screening and obtained a clone expressed differentially in white and yellow petals. The deduced amino acid sequence of the protein (designated CmCCD4a) encoded by the clone was highly homologous to the sequence of carotenoid cleavage dioxygenase. All the white-flowered chrysanthemum cultivars tested showed high levels of CmCCD4a transcript in their petals, whereas most of the yellow-flowered cultivars showed extremely low levels. Expression of CmCCD4a was strictly limited to flower petals and was not detected in other organs, such as the root, stem, or leaf. White petals turned yellow after the RNAi construct of CmCCD4a was introduced. These results indicate that in white petals of chrysanthemums, carotenoids are synthesized but are subsequently degraded into colorless compounds, which results in the white color.
Branching Genes Are Conserved across Species. Genes Controlling a Novel Signal in Pea Are Coregulated by Other Long-Distance Signals
Authors: Johnson Xenie , Brcich Tanya , Dun Elizabeth A. , Goussot Magali , Haurogné Karine , Beveridge Christine A. , Rameau Catherine 
Published: September 2006

Abstract
Physiological and genetic studies with the ramosus (rms) mutants in garden pea (Pisum sativum) and more axillary shoots (max) mutants in Arabidopsis (Arabidopsis thaliana) have shown that shoot branching is regulated by a network of long-distance signals. Orthologous genes RMS1 and MAX4 control the synthesis of a novel graft-transmissible branching signal that may be a carotenoid derivative and acts as a branching inhibitor. In this study, we demonstrate further conservation of the branching control system by showing that MAX2 and MAX3 are orthologous to RMS4 and RMS5, respectively. This is consistent with the long-standing hypothesis that branching in pea is regulated by a novel long-distance signal produced by RMS1 and RMS5 and that RMS4 is implicated in the response to this signal. We examine RMS5 expression and show that it is more highly expressed relative to RMS1, but under similar transcriptional regulation as RMS1. Further expression studies support the hypothesis that RMS4 functions in shoot and rootstock and participates in the feedback regulation of RMS1 and RMS5 expression. This feedback involves a second novel long-distance signal that is lacking in rms2 mutants. RMS1 and RMS5 are also independently regulated by indole-3-acetic acid. RMS1, rather than RMS5, appears to be a key regulator of the branching inhibitor. This study presents new interactions between RMS genes and provides further evidence toward the ongoing elucidation of a model of axillary bud outgrowth in pea.
Green Light Adjusts the Plastid Transcriptome during Early Photomorphogenic Development
Authors: Dhingra Amit , Bies Dawn H. , Lehner Kevin R. , Folta Kevin M. 
Published: September 2006

Abstract
During the transition from darkness to light, a suite of light sensors guides gene expression, biochemistry, and morphology to optimize acclimation to the new environment. Ultraviolet, blue, red, and far-red light all have demonstrated roles in modulating light responses, such as changes in gene expression and suppression of stem growth rate. However, green wavebands induce stem growth elongation, a response not likely mediated by known photosensors. In this study, etiolated Arabidopsis (Arabidopsis thaliana) seedlings were treated with a short, dim, single pulse of green light comparable in fluence and duration to that previously shown to excite robust stem elongation. Genome microarrays were then used to monitor coincident changes in gene expression. As anticipated, phytochrome A-regulated, nuclear-encoded transcripts were induced, confirming proper function of the sensitive phytochrome system. In addition, a suite of plastid-encoded transcripts decreased in abundance, including several typically up-regulated after phytochrome and/or cryptochrome activation. Further analyses using RNA gel-blot experiments demonstrated that the response is specific to green light, fluence dependent, and detectable within 30 min. The response obeys reciprocity and persists in the absence of known photosensors. Plastid transcript down-regulation was also observed in tobacco (Nicotiana tabacum) with similar temporal and fluence-response kinetics. Together, the down-regulation of plastid transcripts and increase in stem growth rate represent a mechanism that tempers progression of early commitment to the light environment, helping tailor seedling development during the critical process of establishment.
Rapid Transcriptome Changes Induced by Cytosolic Ca2+ Transients Reveal ABRE-Related Sequences as Ca2+-ResponsivecisElements inArabidopsis
Authors: Kaplan Boaz , Davydov Olga , Knight Heather , Galon Yael , Knight Marc R. , Fluhr Robert , Fromm Hillel 
Published: September 2006

AbstractThe regulation of gene expression by cellular calcium is crucial for plant defense against biotic and abiotic stresses. However, the number of genes known to respond to specific transient calcium signals is limited, and as yet there is no definition of a calcium-responsive cis element in plants. Here, we generated specific cytosolic calcium transients in intact Arabidopsis thaliana seedlings and linked them to early transcriptome changes, followed by bioinformatic analysis of the responsive genes. A cytosolic calcium transient induced by calmodulin antagonists and blocked by lanthanides was characterized using aequorin-based luminometry and photon imaging. Analysis of transcriptome changes revealed 230 calcium-responsive genes, of which 162 were upregulated and 68 were downregulated. These include known early stress-responsive genes as well as genes of unknown function. Analysis of their upstream regions revealed, exclusively in the upregulated genes, a highly significant occurrence of a consensus sequence (P &lt; 10−13) comprising two abscisic acid–specific cis elements: the abscisic acid–responsive element (ABRE; CACGTG[T/C/G]) and its coupling element ([C/A]ACGCG[T/C/A]). Finally, we show that a tetramer of the ABRE cis element is sufficient to confer transcriptional activation in response to cytosolic Ca2+ transients. Thus, at least for some specific Ca2+ transients and motif combinations, ABREs function as Ca2+-responsive cis elements.
Review article: alcoholic liver disease – pathophysiological aspects and risk factors
Authors: GRAMENZI A. , CAPUTO F. , BISELLI M. , KURIA F. , LOGGI E. , ANDREONE P. , BERNARDI M. 
Published: September 2006

SummaryBackgroundAlcoholic liver disease has a known aetiology but a complex and incompletely known pathogenesis. It is an extremely common disease with significant morbidity and mortality, but the reason why only a relatively small proportion of heavy drinkers progress to advanced disease remains elusive.AimTo recognize the factors responsible for the development and progression of alcoholic liver disease, in the light of current knowledge on this matter.MethodsWe performed a structured literature review identifying studies focusing on the complex pathogenetic pathway and risk factors of alcoholic liver disease.ResultsIn addition to the cumulative amount of alcohol intake and alcohol consumption patterns, factors such as gender and ethnicity, genetic background, nutritional factors, energy metabolism abnormalities, oxidative stress, immunological mechanisms and hepatic co‐morbid conditions play a key role in the genesis and progression of alcoholic liver injury.ConclusionsUnderstanding the pathogenesis and risk factors of alcoholic liver disease should provide insight into the development of therapeutic strategies.
Drug‐induced liver injury in a Swedish University hospital out‐patient hepatology clinic
Authors: DE VALLE M. B. , AV KLINTEBERG V. , ALEM N. , OLSSON R. , BJÖRNSSON E. 
Published: September 2006

SummaryBackgroundLimited data exist on the proportion of drug‐induced liver injury among out‐patients seen in a hepatology clinic.AimTo determine the proportion of drug‐induced liver injury cases, and identify the most important agents and the nature of the liver injury.MethodsA computerized diagnoses database in an out‐patient hepatology clinic in a Swedish University hospital was analysed during the period 1995–2005. All suspected drug‐induced liver injury cases were causality assessed with the International Consensus Criteria.ResultsA total of 1164 cases were seen for the first time during this period. Drug‐induced liver injury with at least a possible causal relationship was found in 77 cases (6.6%), 38 (3.3%) of whom were referred for evaluation to the out‐patient clinic whereas 3% had a follow‐up after hospitalization of drug‐induced liver injury. The median age was 58 years, 43 (56%) were females, a hepatocellular pattern was observed in 37 cases (48%), cholestatic in 31 (40%) and mixed in 12%. Antibiotics were the most common agents causing drug‐induced liver injury followed by non‐steroidal anti‐inflammatory drugs, with diclofenac most often responsible for the drug‐induced liver injury.ConclusionsDrug‐induced liver injury cases constituted 6% of all out‐patients and 3% of referrals and occurred more often in women. Antibiotics and diclofenac were the most common causes of drug‐induced liver injury among out‐patients.
A high‐resolution comparative radiation hybrid map of equine chromosome 4q12–q22
Authors: Dierks C. , Mömke S. , Drögemüller C. , Leeb T. , Chowdhary B. P. , Distl O. 
Published: September 2006

SummaryIn this study, we present a comprehensive 5000‐rad radiation hybrid map of a 40‐cM region on equine chromosome 4 (ECA4) that contains quantitative trait loci for equine osteochondrosis. We mapped 29 gene‐associated sequence tagged site markers using primers designed from equine expressed sequence tags or BAC clones in the ECA4q12–q22 region. Three blocks of conserved synteny, showing two chromosomal breakpoints, were identified in the segment of ECA4q12–q22. Markers from other segments of HSA7q mapped to ECA13p and ECA4p, and a region of HSA7p was homologous to ECA13p. Therefore, we have improved the resolution of the human–equine comparative map, which allows the identification of candidate genes underlying traits of interest.
Functional effects of genetic variants in the 11β‐hydroxylase (CYP11B1) gene
Authors: Barr Marianne , MacKenzie Scott M. , Wilkinson Donna M. , Holloway Christine D. , Friel Elaine C. , Miller Stephen , MacDonald Tom , Fraser Robert , Connell John M. C. , Davies Eleanor 
Published: September 2006

SummaryObjective  We previously described an association between the −344C/T 5′‐untranslated region (UTR) polymorphism in the CYP11B2 (aldosterone synthase) gene and hypertension with a raised aldosterone to renin ratio (ARR); the same genetic variant is also associated with impaired adrenal 11β‐hydroxylase efficiency. The −344 polymorphism does not seem to be functional, so is likely to be in linkage with variants in CYP11B1 that determine the associated variation in 11β‐hydroxylase efficiency. We therefore aimed to determine whether there is an association between CYP11B1 variants and hypertension and/or an altered ARR.Design and measurements  We screened 160 subjects divided into four groups, normotensive controls, unselected hypertensive subjects, and hypertensive subjects with either a high (≥ 750) or low ARR (≤ 200), for variants in the coding region of CYP11B1 by single‐stranded conformation polymorphism (SSCP) and direct sequencing. The effects of these variants on enzyme function were assessed by conversion of 11‐deoxycortisol to cortisol and 11‐deoxycorticosterone (DOC) to corticosterone.Results  Eight novel missense mutations were identified in the CYP11B1 gene that alter the encoded amino acids: R43Q, L83S, H125R, P135S, F139L, L158P, L186V and T196A. In each case they were heterozygous changes. However, no mutations were identified that could account for hypertension and/or a raised ARR. The variants L158P and L83S severely impaired enzyme function while R43Q, F139L, P135S and T196A enzymes resulted in product levels that were approximately 30–50% that of wild‐type levels. The variant enzymes H125R and L186V resulted in substrate‐specific alterations in enzyme function. H125R decreased conversion of 11‐deoxycortisol to cortisol and L186V increased 11‐deoxycortisol conversion. Neither had an effect on the conversion of DOC to corticosterone.Conclusion  No variants were identified in the coding region of CYP11B1 that could account for hypertension and/or a raised ARR. However, this in vitro study identifies the importance of these affected residues to enzyme function and will inform subsequent studies of structure–function relationships.
Differing activation status and immune effector molecule expression profiles of neonatal and maternal lymphocytes in an African population
Authors: Engelmann Ilka , Moeller Ulrike , Santamaria Andrea , Kremsner Peter G. , Luty Adrian J.F. 
Published: September 2006

SummaryHigher susceptibility of newborns to infections has been attributed to the hypo‐responsiveness of their cellular immune system. Here we compared the activation status and expression of cytokines and cytotoxic molecules of cord versus maternal peripheral blood mononuclear cells in an African population. Human leucocyte antigen‐DR was expressed on a lower percentage of cord compared to maternal γδ and CD3+ T cells. Similarly, a lower proportion of cord versus maternal γδ and CD3+ T cells displayed perforin, granzyme B and cytokine activity either ex vivo or following non‐specific stimulation in vitro. In contrast, comparable proportions of cord and maternal CD94+ CD3– natural killer (NK) cells showed perforin and granzyme B expression ex vivo. We conclude that cord blood γδ and CD3+ T cells are functionally hypo‐responsive as reflected by reduced numbers of such cells expressing either an activation marker, T helper 1 (Th1) and Th2 cytokines or cytotoxic effector molecules. The similarity in numbers of cord and maternal CD94+ CD3– cells expressing cytotoxic effector molecules suggests that neonatal Africans' NK cells may be functionally mature.
ORIGINAL ARTICLE: Fish species richness decreases with salinity in tropical coastal lagoons
Authors: Sosa‐López Atahualpa , Mouillot David , Ramos‐Miranda Julia , Flores‐Hernandez Domingo , Chi Thang Do 
Published: September 2006

AbstractAim  To analyse the relationship between fish species richness and salinity, and to provide a simple linear model for fish diversity trends across salinity gradients in a tropical coastal lagoon that can be compared with other similar ecosystems and other communities. To reinforce our conclusions, the salinity–fish richness relationship was investigated at different spatial scales (sampling station, set of stations and whole lagoon) and for two different periods, separated by 18 years.Location  The Terminos coastal lagoon, a shallow tropical lagoon (mean maximum depths ranging between 3.5 and 4.5 m), is located in the southern Gulf of Mexico (18.5–18.8° N, 91.3–91.9° W). The lagoon is 70 km long and 30 km wide, with a surface area of 1700 km2.Methods  Fish sampling, individual identification to the species level, and environmental variable measurements were carried out monthly at 17 sampling points. Multiple regression analysis with a backward selection procedure was used to relate fish species richness to environmental variables. Other statistical techniques, including cluster analysis and ancova, were applied to experimental data surveys.Results  Among the different environmental variables, salinity was significantly and consistently related to fish species richness, whatever the period and the scale of observation. We found mainly significant negative correlations (P < 0.05) between fish species richness and salinity when sampling stations were analysed individually, and particularly for the river runoff zones with high variation in salinity throughout the year. For the entire lagoon, robust negative linear models were observed when fish species richness was organized into salinity ranges, with salinity explaining c. 8% of the variation in mean fish species richness (in a multiple regression analysis; 63–93% when considered in isolation).Main conclusions  In the Terminos lagoon the relationship between fish species richness and salinity is mainly negative on any spatial scale. This result may be due partially to the penetration of freshwater fishes into estuarine areas following freshwater discharges, and partially to the dominance of estuarine taxa more able to tolerate low than high salinity values. Finally, we suggest that the ‘realized’ ecotone, where species from different origins really mix, is situated between 5 and 10‰, corresponding to the highest fish richness.
Role of an opportunistic pathogen in the decline of stressed oak trees
Authors: MARÇAIS B. , BRÉDA N. 
Published: September 2006

Summary

The importance of opportunistic pathogens, in particular Armillaria species, in forest decline has often been open to debate.
In order to assess the role of Armillaria gallica in the decline of oak trees, 60 Quercus robur trees with high (HIP trees) or low (LIP trees) levels of A. gallica inoculum, as measured by the density of epiphytic rhizomorphs on the root collar, were artificially defoliated for 2 years. Half of the HIP trees were treated when first defoliated with boric acid to reduce the A. gallica inoculum potential (BHIP trees). The ability of in situ rhizomorphs to colonize plant material was similar for LIP and BHIP, but was lower than in HIP trees, indicating that the boric acid treatment reduced the level of A. gallica inoculum.
Tree growth was similar between treatments as determined by dendrochronological comparisons. Although defoliation greatly reduced both tree growth and sapwood starch reserves at the beginning of autumn, growth response to defoliation and sapwood starch concentration at the beginning of autumn were similar for LIP, BHIP and HIP trees.
HIP trees suffered considerably greater crown deterioration and mortality following defoliation than either BHIP or LIP trees (62%, 32% and 5% mortality rates, respectively). The trees that died had very low sapwood starch concentrations. In addition, at similar levels of sapwood starch, HIP trees were much more likely to die than LIP or BHIP trees.
Two other factors influenced tree mortality. Past stress that reduced the tree growth a few years prior to the start of the experiment was shown to alter the tree's ability to cope with defoliation. Oak mildew selectively infected the defoliated trees and increased the severity of the defoliation stress.
Thus, trees subjected to high level of A. gallica inoculum had a lower ability to overcome the defoliation stress. These findings support the forest decline models developed by Manion in 1991 and show that it is important to take into account the role of opportunistic pathogens in tree mortality processes.
Genetic structure at range edge: low diversity and high inbreeding in Southeast Asian mangrove (Avicennia marina) populations
Authors: ARNAUD‐HAOND S. , TEIXEIRA S. , MASSA S. I. , BILLOT C. , SAENGER P. , COUPLAND G. , DUARTE C. M. , SERRÃO E. A. 
Published: September 2006

AbstractUnderstanding the genetic composition and mating systems of edge populations provides important insights into the environmental and demographic factors shaping species’ distribution ranges. We analysed samples of the mangrove Avicennia marina from Vietnam, northern Philippines and Australia, with microsatellite markers. We compared genetic diversity and structure in edge (Southeast Asia, and Southern Australia) and core (North and Eastern Australia) populations, and also compared our results with previously published data from core and southern edge populations. Comparisons highlighted significantly reduced gene diversity and higher genetic structure in both margins compared to core populations, which can be attributed to very low effective population size, pollinator scarcity and high environmental pressure at distribution margins. The estimated level of inbreeding was significantly higher in northeastern populations compared to core and southern populations. This suggests that despite the high genetic load usually associated with inbreeding, inbreeding or even selfing may be advantageous in margin habitats due to the possible advantages of reproductive assurance, or local adaptation. The very high level of genetic structure and inbreeding show that populations of A. marina are functioning as independent evolutionary units more than as components of a metapopulation system connected by gene flow. The combinations of those characteristics make these peripheral populations likely to develop local adaptations and therefore to be of particular interest for conservation strategies as well as for adaptation to possible future environmental changes.