bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinct biphasic histomorphological pattern in gastrointestinal stromal tumours (GISTs) with common primary mutations but divergent molecular cytogenetic progression
Authors: Agaimy Abbas , Haller Florian , Gunawan Bastian , Wünsch Peter H , Füzesi László
Published: February 2009

Aims:  The morphological diversity of gastrointestinal stromal tumours (GISTs) is well appreciated. The aim of this study was to shed light on the molecular pathogenesis of GISTs displaying a distinct biphasic histomorphological pattern, which is poorly understood.

Methods and results:  Six biphasic gastric GISTs (four high, one intermediate and one low risk for aggressive behaviour) were studied by histological, immunohistochemical, molecular and comparative genomic hybridization methods. The different tumour components were designated as primary and secondary compartments, based on cellularity and mitotic index. In addition, metastases from two patients were analysed separately. According to the classification of Miettinen et al., four biphasic histomorphological patterns were seen: (i) sclerosing spindle cell/dyscohesive or paraganglioma‐like epithelioid (n = 2); (ii) sarcomatous spindle cell/pleomorphic sarcomatous spindle cell (n = 1); (iii) sarcomatous spindle cell/sarcomatous epithelioid (n = 2); and (iv) sclerosing epithelioid/hypercellular epithelioid/sarcomatous epithelioid (n = 1) morphology. In each case, both tumour compartments revealed the same KIT (n = 5) or platelet‐derived growth factor receptor‐alpha (n = 1) mutation, as well as common chromosomal imbalances reflecting their common clonal origin. Additional chromosomal imbalances were detected in the secondary tumour compartments and their respective metastases.

Conclusions:  Our results indicate that the intratumoral phenotypic diversity in GIST reflects histomorphological progression, which is associated with higher chromosomal instability, irrespective of the primary mutation.
Haeme oxygenase‐1 promoter polymorphism is an independent prognostic marker of gastrointestinal stromal tumour
Authors: Vashist Yogesh K , Uzunoglu Guentac , Cataldegirmen Guelle , Kalinin Viacheslar , Schurr Paulus , Koenig Alexandra M , Thieltges Sabrina , Zehler Oliver , Schneider Claus , Izbicki Jacob R , Yekebas Emre F
Published: February 2009

Aims:  Gastrointestinal stromal tumours (GISTs) display genetic alterations on chromosome 22. GTn repeat (GTn) length polymorphism in the promoter of haeme oxygenase‐1 gene (HMOX‐1) is located on chromosome 22 and associated with malignant growth. The aim was to investigate the role of HMOX‐1 promoter polymorphism in GIST patients.

Methods and results:  Tumour and corresponding healthy tissue DNA of 44 patients who underwent surgical resection of GIST were analysed by polymerase chain reaction, capillary electrophoresis and DNA sequencing. GTn polymorphism was classified into short (S) and long (L) allele. There was no difference detected in GTn genotype between tumour and healthy tissue DNA. Short GTn allele (SGTn) was significantly associated with metastatic disease, higher tumour recurrence rates and high risk GIST (consensus criteria 2001). Furthermore, SGTn allele carriers had significantly shorter disease‐free and overall survival (log rank test, P < 0.0001). On multivariate Cox regression analysis, GTn polymorphism was identified as an independent prognostic factor for survival (P = 0.001).

Conclusions:  HMOX‐1 promoter GTn polymorphism is a potential prognostic marker and may help to allocate patients to different risk groups, customized therapy and follow‐up. Haeme oxygenase‐1 could represent an important candidate gene in the pathogenesis and growth of GIST.
Down‐regulated expression of the TSAP6 protein in liver is associated with a transition from cirrhosis to hepatocellular carcinoma
Authors: Caillot Frédérique , Daveau Romain , Daveau Maryvonne , Lubrano Jean , Saint‐Auret Gaëlle , Hiron Martine , Goria Odile , Scotte Michel , Francois Arnaud , Salier Jean‐Philippe
Published: February 2009

Aims:  Hepatocellular carcinoma (HCC) results from cirrhosis and, in Western Europe, hepatitis C virus and alcoholism are the predominant causes of this disease. We recently documented a global transcript repression in hepatocarcinoma nodules. The tumour suppressor activated pathway‐6 (TSAP6) transcript codes for a transmembrane molecule that is an inducer of a caspase‐3‐dependent apoptotic pathway. The down‐regulation of TSAP6 transcripts in HCC and perinodular cirrhosis, which contrasts with a sustained transcript level in HCC‐free cirrhosis, has suggested that this hepatic protein level may provide a prognostic marker for HCC occurrence.

Methods and results:  This protein was quantified by semiquantitative assessment of immunohistochemistry on samples from 42 cases HCC‐free cirrhosis, 49 cases cirrhosis with HCC, 43 HCC associated with healthy liver and 31 controls. TSAP6 expression was linked to the liver state, healthy or cirrhotic without or with an HCC and to tumour grade.

Conclusions:  With biopsies periodically performed for surveillance purposes, the decreased expression of TSAP6 in cirrhotic tissue could reflect a decrease in the apoptotic process and could be interpreted as a warning sign. This evaluation of the TSAP6 level in cirrhotic liver conveys predictive information for the development of HCC.
Prognostic value of PRL‐3 overexpression in early stages of colonic cancer
Authors: Xing Xiaofang , Peng Lirong , Qu Like , Ren Tingting , Dong Bin , Su Xiangqian , Shou Chengchao
Published: February 2009

Aims:  High expression of phosphatase of regenerating liver (PRL‐3) has been implicated in cancer invasion and metastasis, indicating a close link between PRL‐3 and cancer development. The aim was to investigate the significance of PRL‐3 expression in the prognosis of colonic cancer.

Methods and results:  Expression of PRL‐3 protein in tissue slides obtained from surgical resection of primary colonic cancer was measured by immunohistochemistry using a specific anti‐PRL‐3 monoclonal antibody. Archived tissue specimens from 273 colonic cancers and 236 matched specimens of adjacent normal colonic mucosa with a median follow‐up of 57 months were examined. Multivariate analysis showed that PRL‐3 was an independent prognostic marker for disease‐free survival [DFS; hazard ratio (HR) 1.538, P = 0.035]. More importantly, the expression of PRL‐3 showed significant negative correlation with DFS (P = 0.018) in patients in the early stages (stage I and II). Patients with high levels of PRL‐3 expression in the adjacent normal mucosa also had a significant worse survival rate (DFS 0.0% versus 74.4%, P = 0.001), and PRL‐3 expression remained an independent prognostic marker for DFS (HR 3.0, 95% confidence interval 1.7, 5.3, P < 0.001).

Conclusions:  PRL‐3 may predict poor survival and act as a promising biomarker for individualized therapy for patients with colonic cancer, especially for those diagnosed at an early stage.
Differentiation markers in pancreatic head adenocarcinomas: MUC1 and MUC4 expression indicates poor prognosis in pancreatobiliary differentiated tumours
Authors: Westgaard Arne , Schjølberg Aasa R , Cvancarova Milada , Eide Tor J , Clausen Ole Petter F , Gladhaug Ivar P
Published: February 2009

Aims:  To examine how accurately immunohistochemical markers discriminate between pancreatobiliary and intestinal‐type adenocarcinomas in the pancreatic head and to explore the prognostic importance of these markers among each of these histological types.

Methods and results:  Histopathological features of 114 consecutively resected adenocarcinomas of pancreatobiliary (n = 67) and intestinal (n = 47) type of differentiation were recorded according to a standardized protocol. Immunohistochemistry for cytokeratin (CK) 7, CK20, MUC1, MUC2, MUC4 and CDX2 was performed on tissue microarrays. Classification of the adenocarcinomas based on immunohistochemistry was compared with the morphological evaluation of histological type. Presence of CK7 and MUC4, and absence of CDX2, were independent predictors of pancreatobiliary versus intestinal type. Using these markers to optimize immunohistochemical classification, agreement between immunohistochemical and morphological classification was only moderate (κ = 0.53). In pancreatobiliary differentiated tumours, MUC1 and/or MUC4 expression was an independent prognostic factor (hazard ratio 2.02, 95% confidence interval 1.02, 3.98) when adjusting for nodal involvement, vessel involvement and tumour size. In intestinally differentiated tumours, none of the markers was significantly associated with prognosis.

Conclusions:  Agreement between immunohistochemical and morphological classification of pancreatic head adenocarcinomas is moderate. In pancreatobiliary adenocarcinomas, MUC1 and/or MUC4 expression indicates a particularly poor prognosis.
Patterns of seed dispersal and pollen flow inQuercus garryana(Fagaceae) following post‐glacial climatic changes
Authors: Marsico Travis D. , Hellmann Jessica J. , Romero‐Severson Jeanne
Published: February 2009

Aim We examined the genetic structure ofQuercus garryanato infer post‐glacial patterns of seed dispersal and pollen flow to test the hypotheses that (1) peripheral populations are genetically distinct from core populations and from one another; (2) genetic diversity declines towards the poleward edge of the species’ range; and (3) genetic diversity in the chloroplast genome, a direct measure of seed dispersal patterns, declines more sharply with increasing latitude than diversity in the nuclear genome. We address our findings in the context of known historical oak distribution from pollen core data derived from previously published research.

Location Oak–savanna ecosystems from southern Oregon, USA (core populations/non‐glaciated range) northward to Vancouver Island, British Columbia, Canada (peripheral populations/glaciated range).

Methods We genotyped 378 trees from 22 sites with five chloroplast and seven nuclear microsatellite loci. For both sets of markers, we estimated genetic diversity and differentiation using an analysis of molecular variance and generated Mantel correlograms to detect genetic and geographical distance correlations. For the nuclear markers, we also used a Bayesian approach to infer population substructure.

Results There was a large degree of population differentiation revealed by six chloroplast haplotypes, with little (≤ 3) or no haplotype diversity within sites. Peripheral island locations shared the same, maternally inherited chloroplast haplotype, whereas locations in mainland Washington had greater haplotype diversity. In contrast, genetic diversity of the nuclear markers was high at all locations sampled. Populations clustered into two groups and were significantly positively correlated over large spatial scales (≤ 200 km), although allele richness decreased significantly with latitude. Population substructure was observed between core and peripheral populations because rare alleles were absent in peripheral localities and common allele frequencies differed.

Main conclusions The observed pattern of chloroplast haplotype loss at the northern periphery suggests restricted seed dispersal events from mainland sites to peripheral islands. This pattern was unexpected, however, as refugial oak populations remained near the current post‐glacial range even during the Last Glacial Maximum. Using nuclear markers, we found high within‐population diversity and population differentiation only over large spatial scales, suggesting that pollen flow is relatively high among populations.
Closing the ring: historical biogeography of the salamander ring species Ensatina eschscholtzii
Authors: Kuchta Shawn R. , Parks Duncan S. , Mueller Rachel Lockridge , Wake David B.
Published: February 2009

Aim  The salamander Ensatina eschscholtzii Gray is a classic example of a ring species, or a species that has expanded around a central barrier to form a secondary contact characterized by species‐level divergence. In the original formulation of the ring species scenario, an explicit biogeographical model was proposed to account for the occurrence of intraspecific sympatry between two subspecies in southern California (the ‘southern closure’ model). Here we develop an alternative ring species model that is informed by the geomorphological development of the California Coast Ranges, and which situates the point of ring closure in the Monterey Bay region of central coastal California (the ‘Monterey closure’ model). Our study has two aims. The first is to use phylogenetic methods to evaluate the two competing biogeographical models. The second is to describe patterns of phylogeographical diversity throughout the range of the Ensatina complex, and to compare these patterns with previously published molecular systematic data.

Location  Western North America, with a focus on the state of California, USA.

Methods  We obtained mitochondrial DNA sequence data from 385 individuals from 224 populations. A phylogeny was inferred using Bayesian techniques, and the geographical distributions of haplotypes and clades were mapped. The two biogeographical ring species models were tested against our Bayesian topology, including the associated Bayesian 95% credible set of trees.

Results  High levels of phylogeographical diversity were revealed, especially in central coastal and northern California. Our Bayesian topology contradicts the Monterey closure model; however, 0.08% of the trees in our Bayesian 95% credible set are consistent with this model. In contrast, the classic ring species biogeographical model (the southern closure model) is consistent with our Bayesian topology, as were 99.92% of the trees in our 95% credible set.

Main conclusions  Our Bayesian phylogenetic analysis most strongly supports the classic ring species model, modified to accommodate an improved understanding of the complex geomorphological evolution of the California Coast Ranges. In addition, high levels of phylogeographical diversity in central and northern California were identified, which is consistent with the striking levels of allozymic differentiation reported previously from those regions.
A phylogeographical analysis across three biogeographical provinces of the south‐eastern Pacific: the case of the marine gastropod Concholepas concholepas
Authors: Cárdenas Leyla , Castilla Juan Carlos , Viard Frédérique
Published: February 2009

Aim  The present‐day population structure of a species reflects the influence of population history as well as contemporary processes. Little is known about the mechanisms that have shaped the geographical distribution of genetic diversity in marine species present on the south‐eastern Pacific (SEP) coast. Here we provide the first comprehensive phylogeographical study of a species distributed along the SEP coast by analysing the endemic and emblematic muricid gastropod Concholepas concholepas.

Location  The study localities were distributed along the SEP coast ranging from Matarani (11° S) to Puerto Eden (49° S), crossing three major biogeographical provinces: Peruvian Province, Intermediate Area and Magellanic Province.

Methods  A total of 337 specimens of C. concholepas were collected from 14 localities in the three biogeographical provinces/areas. Mitochondrial cytochrome oxidase I (COI) gene partial sequences (658 bp) were obtained and analysed using coalescence‐based methods to infer molecular diversity and phylogeographical patterns.

Results  Across the 337 individuals, we found a large diversity, with a total of 179 haplotypes at the COI gene fragment. Although a slight decrease in gene diversity was observed from north to south, an analysis of molecular variance did not reveal any significant spatial population differentiation from Peru to the tip of Chile, not even across the recognized biogeographical boundaries at 30° S and 42° S. In addition, a star‐like haplotype network suggested the past occurrence of a rapid demographic and geographical expansion over the total range examined. Calculations of the onset of this expansion suggest that it might be due to climatic conditions during the period of the marine isotope stage 11 (MIS 11, 400,000 years ago), the longer and warmer interglacial episode during the Pleistocene epoch.

Main conclusions  Our phylogeographical analyses indicate that in the recent past C. concholepas mitochondrial DNA lineages underwent a sudden population expansion event. In addition, our data do not support the hypothesis of concordance between biogeographical barriers and phylogeographical breaks along the SEP coast. These two results are in accordance with the paradigm of high larval dispersal ability in marine species with an extended pelagic larval phase.
Climate change, anthropogenic disturbance and the northward range expansion of Lactuca serriola (Asteraceae)
Authors: D’Andrea Luigi , Broennimann Olivier , Kozlowski Gregor , Guisan Antoine , Morin Xavier , Keller‐Senften Julia , Felber François
Published: February 2009

Aim  The distribution range of Lactuca serriola, a species native to the summer‐dry mediterranean climate, has expanded northwards during the last 250 years. This paper assesses the influence of climate on the range expansion of this species and highlights the importance of anthropogenic disturbance to its spread.

Location  Central and Northern Europe.

Methods  Data on the geographic distribution of L. serriola were assembled through a literature search as well as through floristic and herbarium surveys. Maps of the spread of L. serriola in Central and Northern Europe were prepared based on herbarium data. The spread was assessed more precisely in Germany, Austria and Great Britain by pooling herbarium and literature data. We modelled the bioclimatic niche of the species using occurrence and climatic data covering the last century to generate projections of suitable habitats under the climatic conditions of five time periods. We tested whether the observed distribution of L. serriola could be explained for each time period, assuming that the climatic niche of the species was conserved across time.

Results  The species has spread northwards since the beginning of the 19th century. We show that climate warming in Europe increased the number of sites suitable for the species at northern latitudes. Until the late 1970s, the distribution of the species corresponded to the climatically suitable sites available. For the last two decades, however, we could not show any significant relationship between the increase in suitable sites and the distributional range change of L. serriola. However, we highlight potential areas the species could spread to in the future (Great Britain, southern Scandinavia and the Swedish coast). It is predominantly non‐climatic influences of global change that have contributed to its rapid spread.

Main conclusions  The observation that colonizing species are not filling their climatically suitable range might imply that, potentially, other ruderal species could expand far beyond their current range. Our work highlights the importance of historical floristic and herbarium data for understanding the expansion of a species. Such historical distributional data can provide valuable information for those planning the management of contemporary environmental problems, such as species responses to environmental change.
Predicting ischaemic stroke subtype from presenting systolic blood pressure: the BASIC Project
Authors: Meurer W. J. , Sánchez B. N. , Smith M. A. , Lisabeth L. D. , Majersik J. J. , Brown D. L. , Uchino K. , Bonikowski F. P. , Mendizabal J. E. , Zahuranec D. B. , Morgenstern L. B.
Published: February 2009

Objective.  We hypothesized that low presenting systolic blood pressure (SBP) predicted cardioembolic stroke aetiology.

Design.  Active and passive surveillance were used to identify all ischaemic strokes as part of the Brain Attack Surveillance in Corpus Christi (BASIC) population‐based study. Multinomial logistic regression was used to examine the association between stroke subtype and first documented SBP in the medical record.

Setting.  Nueces County, TX, USA (313 645 residents in 2000). The community is urban with the majority of the population residing in the city of Corpus Christi. The area is served by seven adult acute care hospitals.

Patients.  Three hundred and eight cases with completed ischaemic stroke and determined subtype aetiology between January 2000 and December 2002.

Results.  Lower presenting SBP was associated with stroke subtype (P = 0.001). This association remained significant in the final model adjusted for age and history of coronary artery disease. The odds of cardioembolic versus small vessel occlusion increased by 20% (OR = 1.20, 95% CI: 1.07–1.35) for every 10 mmHg decrease in presenting SBP. Other covariates including race/ethnicity, gender, history of hypertension, and diabetes were neither significant predictors of stroke subtype, nor did they confound the association of SBP and stroke subtype. A 5 year increase in age increased the odds of cardioembolic subtype by 25% (OR = 1.25, 95% CI: 1.07–1.47).

Conclusions.  Lower initial SBP and older age at ischaemic stroke presentation were associated with cardioembolic stroke. Suspicion of cardioembolic stroke should be increased in those presenting with low SBP.
The emerging concept of functional amyloid
Authors: Maury C. P. J.
Published: February 2009

Although amyloid has usually been considered a pathological structure, growing evidence indicates that amyloid may also be a productive part of cell biology contributing to normal physiology. In fact, amyloid formation seems to be an intrinsic propensity of polypeptides in general and the amyloid β‐fold an evolutionary highly conserved structure. Functional amyloids have been found in a wide range of organisms, from bacteria to mammals, with functions as diverse as biofilm formation, development of aerial structures, scaffolding, regulation of melanin synthesis, epigenetic control of polyamines and information transfer. Obviously, organisms have evolved taking advantage of the canonical amyloid β‐sheet fold, a conformation that possesses both high resistance to proteolysis, self‐replicative properties and capability to function as a molecular memory.
Reliability and validity of the instrumental assessment of implant stability in dry human mandibles
Authors: BROUWERS J. E. I. G. , LOBBEZOO F. , VISSCHER C. M. , WISMEIJER D. , NAEIJE M.
Published: February 2009

Summary  The aim of this study was to determine the intra‐ and interobserver reliability and validity of the instrumental assessment of primary dental implant stability, using resonance frequency analysis (RFA). Sixteen tapered implants and 16 cylindrical implants were installed in eight unfixed dry human mandibles (Cawood classification IV/V). Implant stability quotients (ISQ; the outcome variable of RFA) and peak removal torque were determined. Both the intra‐observer reliability and the interobserver reliability of the RFA measurements were fair‐to‐good, while no significant correlations between the ISQ values and removal torque were found. The removal torque of the cylindrical implants was higher than that of the tapered implants. The smallest detectable difference was almost nine ISQ units. Within the limitations of the present dry cadaver study, it was concluded that (i) primary dental implant stability can be assessed reliably with RFA measurements, (ii) the concurrent validity between RFA measurements and removal torque is poor, (iii) cylindrical implants may be more stable than tapered ones and (iv) two subsequent readings of RFA measurements need to differ at least nine ISQ units before the difference between the two measurements can be considered statistically significant. More research is needed to see whether these conclusions can be extrapolated to the clinical situation, including the assessment of implants during function (secondary stability).
Genomic dissection of drought resistance in durum wheat × wild emmer wheat recombinant inbreed line population
Authors: PELEG ZVI , FAHIMA TZION , KRUGMAN TAMAR , ABBO SHAHAL , YAKIR DAN , KOROL ABRAHAM B. , SARANGA YEHOSHUA
Published: February 2009

Drought is the major factor limiting wheat productivity worldwide. The gene pool of wild emmer wheat,Triticum turgidumssp.dicoccoides, harbours a rich allelic repertoire for morpho‐physiological traits conferring drought resistance. The genetic and physiological bases of drought responses were studied here in a tetraploid wheat population of 152 recombinant inbreed lines (RILs), derived from a cross between durum wheat (cv. Langdon) and wild emmer (acc# G18‐16), under contrasting water availabilities. Wide genetic variation was found among RILs for all studied traits. A total of 110 quantitative trait loci (QTLs) were mapped for 11 traits, with LOD score range of 3.0–35.4. Several QTLs showed environmental specificity, accounting for productivity and related traits under water‐limited (20 QTLs) or well‐watered conditions (15 QTLs), and in terms of drought susceptibility index (22 QTLs). Major genomic regions controlling productivity and related traits were identified on chromosomes 2B, 4A, 5A and 7B. QTLs for productivity were associated with QTLs for drought‐adaptive traits, suggesting the involvement of several strategies in wheat adaptation to drought stress. Fifteen pairs of QTLs for the same trait were mapped to seemingly homoeologous positions, reflecting synteny between the A and B genomes. The identified QTLs may facilitate the use of wild alleles for improvement of drought resistance in elite wheat cultivars.
Illuminated behaviour: phytochrome as a key regulator of light foraging and plant anti‐herbivore defence
Authors: BALLARÉ CARLOS L.
Published: February 2009

In many ecological scenarios, the success of an individual plant is defined by the behavioural decisions that it makes when confronted with the risks of competition with other plants, and biomass losses to insect herbivores. These decisions involve expression of shade avoidance responses and induced chemical defences. Because these responses are costly, they frequently engender resource allocation dilemmas. In this review, I discuss the mechanisms that trigger adaptive responses to competitors and herbivores, highlighting the role of phytochromes as central organizers of the overall resource allocation strategy of plants. Phytochromes sense the reduction in the red to far‐red (R : FR) ratio of sunlight caused by the proximity of other plants. Shade‐intolerant plants respond to low R : FR ratios with shade avoidance behaviours and reduced investment in defence. Pfr depletion leads to increased stability of growth‐promoting phytochrome‐interacting factors (PIFs), and results in the production of auxins and gibberellins, degradation of DELLA proteins, which are repressors of PIFs, and reduced sensitivity to jasmonates. Thus, phytochrome appears to fulfil its organizational role by regulating the relative strength of the signalling circuits controlled by growth‐related and defence‐related hormones. I point out cases of signalling redundancy and discuss the significance of recent work on hormone signalling for our understanding of the mechanisms that control adaptive plant behaviour.
cpFBPaseII, a novel redox‐independent chloroplastic isoform of fructose‐1,6‐bisphosphatase
Authors: SERRATO ANTONIO JESÚS , YUBERO‐SERRANO ELENA MARÍA , SANDALIO LUISA MARÍA , MUÑOZ‐BLANCO JUAN , CHUECA ANA , CABALLERO JOSÉ LUIS , SAHRAWY MARIAM
Published: February 2009

A full‐length FBPase cDNA has been isolated from Fragaria × ananassa (strawberry) corresponding to a novel putative chloroplastic FBPase but lacking the regulatory redox domain, a characteristic of the plastidial isoenzyme (cpFBPaseI). Another outstanding feature of this novel isoform, called cpFBPaseII, is the absence of the canonical active site. Enzymatic assays with cpFBPaseII evidenced clear Mg2+‐dependent FBPase activity and a Km for fructose‐1,6‐bisphosphate (FBP) of 1.3 mm. Immunolocalization experiments and chloroplast isolation confirmed that the new isoenzyme is located in the stroma. Nevertheless, unlike cpFBPaseI, which is redox activated, cpFBPaseII did not increase its activity in the presence of either DTT or thioredoxin f (TRX f) and is resistant to H2O2 inactivation. Additionally, the novel isoform was able to complement the growth deficiency of the yeast FBP1 deletion fed with a non‐fermentable carbon source. Furthermore, orthologues are restricted to land plants, suggesting that cpFBPaseII is a novel and an intriguing chloroplastic FBPase that emerged late in the evolution of photosynthetic organisms, possibly because of a pressing need of land plants.
Depth and controls of Ca‐rhodochrosite precipitation in bioturbated sediments of the Eastern Equatorial Pacific, ODP Leg 201, Site 1226 and DSDP Leg 68, Site 503
Authors: MEISTER PATRICK , BERNASCONI STEFANO M. , AIELLO IVANO W. , VASCONCELOS CRISÓGONO , MCKENZIE JUDITH A.
Published: February 2009

The occurrence of early diagenetic Ca‐rhodochrosite [(Mn,Ca)CO3] is reported in association with ‘griotte’‐type nodular limestones from basinal settings in the geological record; however, without the comparison of analogous modern examples, the controls on precipitation remain speculative. Here the findings of four layers of primary Ca‐rich rhodochrosite recovered from a modern deep‐sea setting in the Eastern Equatorial Pacific, from bioturbated sediments 300 m below sea floor, are reported (Ocean Drilling Program, Leg 201, Site 1226). The mineralogy is similar to cements in burrows recovered during Deep Sea Drilling Project Leg 68 at Eastern Equatorial Pacific Site 503 and from Ca‐rhodochrosite laminae in sediments of the central Baltic Sea. Petrographic relationships and constant oxygen isotopic compositions in the Ca‐rhodochrosite around 5‰ at all depths indicate a shallow burial depth of formation. The onset of 1‰ heavier oxygen isotope composition of Ca‐rhodochrosite at Site 503, about 30 m below the Pliocene/Pleistocene boundary, further suggests that precipitation occurs in the range of 30 m below sea floor. The approximate depth of formation allowed an approximate empirical fractionation factor for marine Ca‐rhodochrosite to be constrained that strongly differs from previously published theoretical values. Based on the approximate precipitation depth, authigenic Ca‐rhodochrosite forms within the SO42−‐reduction zone. Moderately negative δ13C values (around −3‰) and total organic carbon lower than 2 wt% indicate a relatively low contribution of CO32− from organic C mineralization within the expanded redox zonation in the Eastern Equatorial Pacific. It is suggested that the alkalinity is increased by a rise in pH at focused sites of Mn‐reduction coupled with S2− oxidation. High concentrations of Mn‐oxide can accumulate in layers or burrows because of Mn‐cycling in suboxic sediments as suggested for the Baltic Sea Ca‐rhodochrosites. This study demonstrates how early diagenetic precipitates document biogeochemical processes from past diagenetic systems.
Apoplastic plant subtilases support arbuscular mycorrhiza development in Lotus japonicus
Authors: Takeda Naoya , Sato Shusei , Asamizu Erika , Tabata Satoshi , Parniske Martin
Published: February 2009

In the arbuscular mycorrhiza (AM) symbiosis, plant roots accommodate Glomeromycota fungi within an intracellular compartment, the arbuscule. At this symbiotic interface, fungal hyphae are surrounded by a plant membrane, which creates an apoplastic compartment, the periarbuscular space (PAS) between fungal and plant cell. Despite the importance of the PAS for symbiotic signal and metabolite exchange, only few of its components have been identified. Here we show that two apoplastic plant proteases of the subtilase family are required for AM development. SbtM1 is the founder member of a family of arbuscular mycorrhiza‐induced subtilase genes that occur in at least two clusters in the genome of the legume Lotus japonicus. A detailed expression analysis by RT‐PCR revealed that SbtM1, SbtM3, SbtM4 and the more distantly related SbtS are all rapidly induced during development of arbuscular mycorrhiza, but only SbtS and SbtM4 are also up‐regulated during root nodule symbiosis. Promoter–reporter fusions indicated specific activation in cells that are adjacent to intra‐radical fungal hyphae or in cells that harbour them. Venus fluorescent protein was observed in the apoplast and the PAS when expressed from a fusion construct with the SbtM1 signal peptide or the full‐length subtilase. Suppression of SbtM1 or SbtM3 by RNAi caused a decrease in intra‐radical hyphae and arbuscule colonization, but had no effect on nodule formation. Our data indicate a role for these subtilases during the fungal infection process in particular arbuscule development.
DWARF AND LOW‐TILLERING, a new member of the GRAS family, plays positive roles in brassinosteroid signaling in rice
Authors: Tong Hongning , Jin Yun , Liu Wenbo , Li Feng , Fang Jun , Yin Yanhai , Qian Qian , Zhu Lihuang , Chu Chengcai
Published: February 2009

Rapid progress has been made regarding the understanding of brassinosteroid (BR) signaling in Arabidopsis. However, little is known about BR signaling in monotyledons. Here, we characterized a rice dwarf and low‐tillering (dlt) mutant and cloned the corresponding gene via map‐based cloning. DLT encodes a new member of the plant‐specific GRAS family. The dwarf phenotype of dlt is similar to BR‐deficient or signaling mutants in rice. In addition, both lamina bending and coleoptile elongation assays show that dlt is insensitive or much less responsive to brassinolide (BL), the most active BR, suggesting that DLT is involved in BR signaling. Consistent with this conclusion, the accumulation of transcripts of BR biosynthesis genes in the dlt mutant indicated that DLT is involved in feedback inhibition of BR biosynthesis genes. In addition, transcription of several other BR‐regulated genes is altered in the dlt mutant. Finally, consistent with the fact that DLT is also negatively feedback‐regulated by BR treatment, a gel mobility shift assay showed that OsBZR1 can bind to the DLT promoter through the BR‐response element. Taken together, these studies have enabled us to identify a new signaling component that is involved in several specific BR responses in rice.
A microarray‐based genotyping and genetic mapping approach for highly heterozygous outcrossing species enables localization of a large fraction of the unassembled Populus trichocarpa genome sequence
Authors: Drost Derek R. , Novaes Evandro , Boaventura‐Novaes Carolina , Benedict Catherine I. , Brown Ryan S. , Yin Tongming , Tuskan Gerald A. , Kirst Matias
Published: February 2009

Microarrays have demonstrated significant power for genome‐wide analyses of gene expression, and recently have also revolutionized the genetic analysis of segregating populations by genotyping thousands of loci in a single assay. Although microarray‐based genotyping approaches have been successfully applied in yeast and several inbred plant species, their power has not been proven in an outcrossing species with extensive genetic diversity. Here we have developed methods for high‐throughput microarray‐based genotyping in such species using a pseudo‐backcross progeny of 154 individuals of Populus trichocarpa and P. deltoides analyzed with long‐oligonucleotide in situ‐synthesized microarray probes. Our analysis resulted in high‐confidence genotypes for 719 single‐feature polymorphism (SFP) and 1014 gene expression marker (GEM) candidates. Using these genotypes and an established microsatellite (SSR) framework map, we produced a high‐density genetic map comprising over 600 SFPs, GEMs and SSRs. The abundance of gene‐based markers allowed us to localize over 35 million base pairs of previously unplaced whole‐genome shotgun (WGS) scaffold sequence to putative locations in the genome of P. trichocarpa. A high proportion of sampled scaffolds could be verified for their placement with independently mapped SSRs, demonstrating the previously un‐utilized power that high‐density genotyping can provide in the context of map‐based WGS sequence reassembly. Our results provide a substantial contribution to the continued improvement of the Populus genome assembly, while demonstrating the feasibility of microarray‐based genotyping in a highly heterozygous population. The strategies presented are applicable to genetic mapping efforts in all plant species with similarly high levels of genetic diversity.
Nuclear accumulation of the ankyrin repeat protein ANK1 enhances the auxin‐mediated transcription accomplished by the bZIP transcription factors BZI‐1 and BZI‐2
Authors: Böttner Stefan , Iven Tim , Carsjens Caroline S. , Dröge‐Laser Wolfgang
Published: February 2009

The tobacco (Nicotiana tabacum) basic leucine zipper (bZIP) transcription factor BZI‐1 has been implicated in auxin‐mediated gene regulation. Yeast two‐hybrid analysis has led to the identification of two BZI‐1 protein interaction partners: the heterodimerizing bZIP factor BZI‐2 and an ankyrin repeat domain protein, ANK1. Analysis in transgenic plants confirms that low levels of functional BZI‐1, BZI‐2 and ANK1 result in reduced auxin responses. This finding indicates that the three proteins act in the same functional context. The in vivo interaction of ANK1 and BZI‐1 has been confirmed by protoplast two‐hybrid analysis, as well as by bimolecular fluorescence complementation (BiFC) studies. Whereas YFP‐BZI‐1 has been found to be localized in the nucleus, YFP‐ANK1 resides in the cytosol. Nevertheless, the inhibition of nuclear export with the inhibitor leptomycin B (LMB) and the co‐expression with BZI‐1, as well as treatment with auxin, results in the accumulation of YFP‐ANK1 in the nucleus. Whereas BZI‐1 is a weak activator, BZI‐1/BZI‐2 heterodimers efficiently support transcription. Importantly, conditions that lead to the accumulation of ANK1 in the nucleus, such as the expression of an ANK1 protein fused to a nuclear localization sequence (NLS) or auxin treatment, lead to a significant enhancement of BZI‐1/BZI‐2‐mediated transcription. We therefore propose a mechanism in which the nuclear accumulation of ANK1 enhances BZI‐1/BZI‐2‐mediated transcription in an auxin‐dependent manner, presumably facilitated by protein–protein interaction. In summary, this study defines novel components in auxin‐dependent signalling and transcriptional control.
Plant extracellular ATP signalling by plasma membrane NADPH oxidase and Ca2+channels
Authors: Demidchik Vadim , Shang Zhonglin , Shin Ryoung , Thompson Elinor , Rubio Lourdes , Laohavisit Anuphon , Mortimer Jennifer C. , Chivasa Stephen , Slabas Antoni R. , Glover Beverley J. , Schachtman Daniel P. , Shabala Sergey N. , Davies Julia M.
Published: February 2009

Extracellular ATP regulates higher plant growth and adaptation. The signalling events may be unique to higher plants, as they lack animal purinoceptor homologues. Although it is known that plant cytosolic free Ca2+can be elevated by extracellular ATP, the mechanism is unknown. Here, we have studied roots ofArabidopsis thalianato determine the events that lead to the transcriptional stress response evoked by extracellular ATP. Root cell protoplasts were used to demonstrate that signalling to elevate cytosolic free Ca2+is determined by ATP perception at the plasma membrane, and not at the cell wall. Imaging revealed that extracellular ATP causes the production of reactive oxygen species in intact roots, with the plasma membrane NADPH oxidase AtRBOHC being the major contributor. This resulted in the stimulation of plasma membrane Ca2+‐permeable channels (determined using patch‐clamp electrophysiology), which contribute to the elevation of cytosolic free Ca2+. Disruption of this pathway in theAtrbohCmutant impaired the extracellular ATP‐induced increase in reactive oxygen species (ROS), the activation of Ca2+channels, and the transcription of the MAP kinase3 gene that is known to be involved in stress responses. This study shows that higher plants, although bereft of purinoceptor homologues, could have evolved a distinct mechanism to transduce the ATP signal at the plasma membrane.
The timing of nectar secretion in staminal and staminodial glands in Lauraceae
Authors: Rohwer J. G.
Published: February 2009

The flowers of many Lauraceae have two kinds of glandular organ: paired glands at the base of the filaments of the third androecial whorl, and staminodes with a glandular head, corresponding to a fourth, sterile androecial whorl. So far, it is unknown why there are two different kinds of organ with apparently the same function. Observations now show that the staminal and the staminodial glands secrete nectar at different times in the heterodichogamous flowering cycle, and are therefore essential for the pollination of bisexual Lauraceae flowers.
Molecular Detection of Phytophthora cryptogea on Calendula officinalis and Gerbera jamesonii Artificially Inoculated with Zoospores
Authors: Li Yuan , Minerdi Daniela , Garibaldi Angelo , Gullino Maria Lodovica
Published: February 2009

In this work, a protocol for zoospores production of Phytophthora cryptogea, an economically important plant pathogen was optimized. Five different concentrations of zoospores (5 × 105, 5 × 104, 5 × 103, 5 × 102, 5 × 101 zoospores/ml) from four different isolates of P. cryptogea (Maria 1, Maria 2, S3 1‐A, Amazzone) were used as inoculum on pot marigold (Calendula officinalis) and gerbera (Gerbera jamesonii) plants. Maria 1 was the most virulent isolate both on pot marigold and gerbera plants according to disease severity. A rapid and sensitive pathogen DNA extraction protocol suitable for large quantities of plant samples was adopted. Conventional polymerase chain reaction (PCR) was able to detect the pathogen in artificially inoculated symptomless pot marigold (collected day 12) and gerbera plants (day 8) after pathogen inoculation, with the suspension of 5 × 105, 5 × 104, 5 × 103P. cryptogea zoospores/ml. Real‐time PCR showed the possibility to detect the pathogen in artificially inoculated symptomless pot marigold (collected day 8) and gerbera plants (day 4) after pathogen inoculation, with the suspension of 5 × 105, 5 × 104P. cryptogea zoospores/ml. The first symptoms appeared on pot marigold plants 14 days after pathogen inoculation and on gerbera plants 10 days after inoculation. Real‐time PCR showed the possibility to detect the pathogen 4 days before conventional PCR and 6 days before the appearance of disease symptoms both on pot marigold and gerbera plants.
The Effect of the Sequence of Infection of the Causal Agents of Sweet Potato Virus Disease on Symptom Severity and Individual Virus Titres in Sweet Potato cv. Beauregard
Authors: Mcgregor Cecilia , Miano Douglas , La Bonte Don , Hoy Mary , Clark Christopher
Published: February 2009

Sweet potato virus disease (SPVD) is caused by dual infection of plants with Sweet Potato Feathery Mottle Virus (SPFMV) and Sweet Potato Chlorotic Stunt Virus (SPCSV). Because SPFMV and SPCSV are transmitted by aphids and whiteflies, respectively, infection in nature occurs independently rather than simultaneously. To investigate the effect of consecutive infection on symptom development and individual virus titres, plants infected with a single virus were later inoculated with the second virus. Symptoms were significantly more severe in plants infected with SPCSV followed by SPFMV compared to plants infected with SPFMV followed by SPCSV. Virus titres were not significantly different for SPCSV, but SPFMV titres, in plants infected with SPCSV followed by SPFMV, were significantly higher than all other treatments. The results indicate that the sequence of infection of sweetpotato plants with the causal agents of SPVD influence the severity of symptoms and SPFMV titres in SPVD affected plants.
ENDOTHELINS AND NADPH OXIDASES IN THE CARDIOVASCULAR SYSTEM
Authors: Dammanahalli Karigowda J , Sun Zhongjie
Published: February 2009

The endothelin (ET) system and NADPH oxidase play important roles in the regulation of cardiovascular function, as well as in the pathogenesis of hypertension and other cardiovascular diseases.

Endothelins activate NADPH oxidases and thereby increase superoxide production, resulting in oxidative stress and cardiovascular dysfunction. Thus, NADPH oxidases may mediate the role of endothelins in some cardiovascular diseases. However, the role of reactive oxygen species (ROS) in mediating ET‐induced vasoconstriction and cardiovascular disease remains under debate, as evidenced by conflicting reports from different research teams. Conversely, activation of NADPH oxidase can stimulate ET secretion via ROS generation, which further enhances the cardiovascular effects of NADPH oxidase. However, little is known about how ROS activate the endothelin system. It seems that the relationship between ET‐1 and ROS may vary with cardiovascular disorders.

Endothelins activate NADPH oxidase via the ET receptor–proline‐rich tyrosine kinase‐2 (Pyk2)–Rac1 pathway. Rac1 is an important regulator of NADPH oxidase. There is ample evidence supporting direct stimulation by Rac1 of NADPH oxidase activity. In addition, Rac1‐induced cardiomyocyte hypertrophy is mediated by the generation of ROS.
δ‐OPIOID RECEPTOR STIMULATION ENHANCES THE GROWTH OF NEONATAL RAT VENTRICULAR MYOCYTES VIA THE EXTRACELLULAR SIGNAL‐REGULATED KINASE PATHWAY
Authors: Zhao Min , Wang Hong‐Xin , Yang Jing , Su Yu‐Hong , Su Rong‐Jian , Wong Tak Ming
Published: February 2009

The aims of the present study were to determine whether δ‐opioid receptor stimulation enhanced proliferation of and to investigate the role of the extracellular signal‐regulated kinase (ERK) pathway in ventricular myocytes from neonatal rats.

At concentratins ranging from 10 nmol/L to 10 µmol/L, [d‐Ala2,d‐Leu5]enkephalin (DADLE) concentration‐dependently promoted myocardial growth and DNA synthesis and altered the cytoskeleton.

At 1 µmol/L, DADLE also increased the expression and phosphorylation of ERK.

These effects of 1 µmol/L DADLE were abolished by 10 µmol/L naltrindole, a selective δ‐opioid receptor antagonist, 10 nmol/L U0126, a selective ERK antagonist, 1 µmol/L staurosporine, an inhibitor of protein kinase (PK) C, and 100 µmol/L Rp‐adenosine 3′,5′‐cyclic monophosphorothioate triethylammonium salt hydrate (Rp‐cAMPS), an inhibitor of PKA.

In conclusion, δ‐opioid receptor stimulation enhances the proliferation and development of the ventricular myocytes of neonatal rats. The ERK pathway and related signalling mechanisms, namely PKC and PKA, are involved.