bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intra‐floral resource partitioning between endemic and invasive flower visitors: consequences for pollinator effectiveness
Authors: JUNKER ROBERT R. , BLEIL RICHARD , DAEHLER CURTIS C. , BLÜTHGEN NICO 
Published: October 2010

1. Sympatric flower visitor species often partition nectar and pollen and thus affect each other's foraging pattern. Consequently, their pollination service may also be influenced by the presence of other flower visiting species. Ants are solely interested in nectar and frequent flower visitors of some plant species but usually provide no pollination service. Obligate flower visitors such as bees depend on both nectar and pollen and are often more effective pollinators.2. In Hawaii, we studied the complex interactions between flowers of the endemic tree Metrosideros polymorpha (Myrtaceae) and both, endemic and introduced flower‐visiting insects. The former main‐pollinators of M. polymorpha were birds, which, however, became rare. We evaluated the pollinator effectiveness of endemic and invasive bees and whether it is affected by the type of resource collected and the presence of ants on flowers.3. Ants were dominant nectar‐consumers that mostly depleted the nectar of visited inflorescences. Accordingly, the visitation frequency, duration, and consequently the pollinator effectiveness of nectar‐foraging honeybees (Apis mellifera) strongly decreased on ant‐visited flowers, whereas pollen‐collecting bees remained largely unaffected by ants. Overall, endemic bees (Hylaeus spp.) were ineffective pollinators.4. The average net effect of ants on pollination of M. polymorpha was neutral, corresponding to a similar fruit set of ant‐visited and ant‐free inflorescences.5. Our results suggest that invasive social hymenopterans that often have negative impacts on the Hawaiian flora and fauna may occasionally provide neutral (ants) or even beneficial net effects (honeybees), especially in the absence of native birds.
Matching thirty years of ecosystem monitoring with a high resolution microfossil record
Authors: HAUPTFLEISCH ULF , EINARSSON ÁRNI , ANDERSEN THORBJøRN J. , NEWTON ANTHONY , GARDARSSON ARNTHOR 
Published: October 2010

Summary1. Monitoring of the ecosystem of Lake Mývatn, Iceland, since 1975 has revealed extreme fluctuations in important food web components, such as chironomids and cladocerans, with amplitudes of several orders of magnitude and a period of 5–8 years. This study uses sediment cores from the lake to examine if the food web fluctuations appear in the microfossil record of the sediment.2. Dating was achieved by means of a combination of 137Cs and volcanic tephra and was fine‐tuned by wiggle‐matching of chironomid microfossil and monitoring data.3. Cladocera exuviae and chironomid egg capsules in the uppermost 34 cm of sediment were compared with the monitoring record that consisted of 30 years of window trap catches of flying chironomids and a 16‐year record of chydorid Cladocera caught in activity traps.4. The observed chironomid and cladoceran population fluctuations were reflected in the sediment record of chironomid eggs and of the exuviae of three of seven cladocerans: Alonella nana, Alona rectangula and Eurycercus lamellatus, which also had the most extreme fluctuations in the monitoring data (3–4 orders of magnitude). Chydorus sphaericus, and to some extent Alona quadrangularis and Acroperus harpae, showed regular fluctuations in the core that the monitoring did not reveal. Density of subfossil chironomid eggs correlated positively with that of larval head capsules but not with other microfossils.5. This study shows a reasonably good correspondence between the fossil records of chironomids and cladocerans on the one hand and biomonitoring data on the other. The results pave the way for an extension of the food web history to much earlier time intervals of the ecosystem, allowing the study of long‐term variation in the food web dynamics, including the impact of climatic variation and other external forcing. The results also indicate the usefulness of chironomid egg capsules in palaeolimnological studies.
The first vitellogenin receptor from a Lepidopteran insect: molecular characterization, expression patterns and RNA interference analysis
Authors: Shu Y. H. , Wang J. W. , Lu K. , Zhou J. L. , Zhou Q. , Zhang G. R. 
Published: October 2010

AbstractThe vitellogenin receptor (VgR) belongs to the low‐density lipoprotein receptor (LDLR) superfamily, and is an important carrier for the uptake of vitellogenin (Vg) into developing oocytes of all oviparous species. The first full‐length message for a VgR from a Lepidopteran insect was cloned and sequenced from the ovary of Spodoptera litura Fabricius (GenBank accession no. GU983858). The coding region consisted of 5370 bp flanked by a 49 bp 5′‐untranslated region (UTR) and a 177 bp 3′‐UTR, which encoded a 1798‐residue protein with a predicted molecular weight (MW) of 201.69 kDa. S. litura VgR (SlVgR)comprised two ligand binding sites with four LDLR class A repeats in the first domain and seven in the second domain, an epidermal growth factor‐like domain containing an LDLR class B repeat and a YWXD motif, a transmembrane domain and a cytoplasmic domain. A phylogenetic relationship placed SlVgR as a separate group from the other insects. SlVgR messenger RNA (mRNA) was specifically expressed in the ovarian tissues. The developmental expression patterns showed that VgR mRNA was first transcribed in 6th day female pupae and the maximum level of VgR mRNA appeared in 36‐h‐old adults. Immunoblot analysis detected an ovary‐specific VgR protein with a MW of ∼200 kDa, whose development profiles were consistent with VgR mRNA expression patterns. RNA inteference (RNAi) specifically disrupted the VgR gene by injection of 3 or 5 µg VgR double‐stranded RNA per insect in 4th or 6th day pupae. RNAi of SlVgR led to a phenotype characterized by high Vg accumulation in the haemolymph, low Vg deposition in the ovary and the failure of insect spawning. These results mean that VgR is critical for binding Vg and transporting it into the oocytes of the insect ovary, thus playing an important role in insect reproduction.
Antifungal mechanisms by which a novel Pseudomonas aeruginosa phenazine toxin kills Candida albicans in biofilms
Authors: Morales Diana K. , Jacobs Nicholas J. , Rajamani Sathish , Krishnamurthy Malathy , Cubillos‐Ruiz Juan R. , Hogan Deborah A. 
Published: October 2010

SummaryPseudomonas aeruginosa produces several phenazines including the recently described 5‐methyl‐phenazine‐1‐carboxylic acid (5MPCA), which exhibits a novel antibiotic activity towards pathogenic fungi such as Candida albicans. Here we characterize the unique antifungal mechanisms of 5MPCA using its analogue phenazine methosulphate (PMS). Like 5MPCA, PMS induced fungal red pigmentation and killing. Mass spectrometry analyses demonstrated that PMS can be covalently modified by amino acids, a process that yields red derivatives. Furthermore, soluble proteins from C. albicans grown with either PMS or P. aeruginosa were also red and demonstrated absorbance and fluorescence spectra similar to that of PMS covalently linked to either amino acids or proteins in vitro, suggesting that 5MPCA modification by protein amine groups occurs in vivo. The red‐pigmented C. albicans soluble proteins were reduced by NADH and spontaneously oxidized by oxygen, a reaction that likely generates reactive oxygen species (ROS). Additional evidence indicated that ROS generation precedes 5MPCA‐induced fungal death. Reducing conditions greatly enhanced PMS uptake by C. albicans and killing. Since 5MPCA was more toxic than other phenazines that are not modified, such as pyocyanin, we propose that the covalent binding of 5MPCA promotes its accumulation in target cells and contributes to its antifungal activity in mixed‐species biofilms.
The group A Streptococcus small regulatory RNA FasX enhances streptokinase activity by increasing the stability of the ska mRNA transcript
Authors: Ramirez‐Peña Esmeralda , Treviño Jeanette , Liu Zhuyun , Perez Nataly , Sumby Paul 
Published: October 2010

SummarySmall RNA molecules play key regulatory roles in many bacterial species. However, little mechanistic data exists for the action of small regulatory RNAs in the human pathogen group A Streptococcus (GAS). Here, we analysed the relationship between a putative GAS sRNA and production of the secreted virulence factor streptokinase (SKA). SKA promotes GAS dissemination by activating conversion of host plasminogen into the fibrin‐degrading protease plasmin. Homologues of the putative sRNA‐encoding gene fibronectin/fibrinogen‐binding/haemolytic‐activity/streptokinase‐regulator‐X (fasX) were identified in four different pyogenic streptococcal species. However, despite 79% fasX nucleotide identity, a fasX allele from the animal pathogen Streptococcus zooepidemicus failed to complement a GAS fasX mutant. Using a series of precisely constructed fasX alleles we discovered that FasX is a bona‐fide sRNA that post‐transcriptionally regulates SKA production in GAS. By base‐pairing to the 5′ end of ska mRNA, FasX enhances ska transcript stability, resulting in a ∼10‐fold increase in SKA activity. Our data provide new insights into the mechanisms used by small regulatory RNAs to activate target mRNAs, and enhances our understanding of the regulation of a key GAS virulence factor.
The customised growth potential: an international research tool to study the epidemiology of fetal growth
Authors: Gardosi Jason , Figueras Francesc , Clausson Britt , Francis Andre 
Published: October 2010

SummaryGardosi J, Figueras F, Clausson B, Francis A. The customised growth potential: an international research tool to study the epidemiology of fetal growth. Paediatric and Perinatal Epidemiology 2010.Customised centiles based on individual fetal growth potential enhance our ability to differentiate between physiological and pathological smallness. A series of studies in different maternity populations has found striking similarities in the way fetal growth varies with maternal and pregnancy related characteristics, and has established the clear advantages of this method over generic, population‐based birthweight or fetal weight standards. The method opens up many new avenues for the retrospective study of risk factors and fetal growth. The findings quantify the strength of association between fetal growth restriction and perinatal outcome, and therefore also highlight the clinical imperative to improve antenatal detection of the at‐risk fetus. Applied prospectively as customised charts, the concept improves the detection of fetal growth restriction and reduces the need for unnecessary investigations.
Favourable prognostic value of antibodies anti‐HSP20 in patients with cystic echinococcosis: a differential immunoproteomic approach
Authors: VACIRCA D. , PERDICCHIO M. , CAMPISI E. , DELUNARDO F. , ORTONA E. , MARGUTTI P. , TEGGI A. , GOTTSTEIN B. , SIRACUSANO A. 
Published: October 2010

SummarySeeking biomarkers reflecting disease development in cystic echinococcosis (CE), we used a proteomic approach linked to immunological characterisation for the identification of respective antigens. Two‐dimensional gel electrophoresis (2‐DE) of sheep hydatid fluid, followed by immunoblot analysis (IB) with sera from patients with distinct phases of disease, enabled us to identify by mass spectrometry heat shock protein 20 (HSP20) as a potential marker of active CE. Using IB, antibodies specific to the 34 kDa band of HSP20 were detected in sera from 61/95 (64%) patients with CE, but not in sera from healthy subjects. IB revealed anti‐HSP20 antibodies in a higher percentage of sera from patients with active disease than in sera from patients with inactive disease (81 vs. 24%; P = 10−4). These primary results were confirmed in a long‐term follow‐up study after pharmacological and surgical treatment. Herewith anti‐HSP20 antibody levels significantly decreased over the course of treatment in sera from patients with cured disease, relative to sera from patients with progressive disease (P = 0·017). Thus, during CE, a comprehensive strategy of proteomic identification combined with immunological validation represents a promising approach for the identification of biomarkers useful for the prognostic assessment of treatment of CE patients.
Comparison of seasonal variations in water‐use efficiency calculated from the carbon isotope composition of tree rings and flux data in a temperate forest
Authors: MICHELOT ALICE , EGLIN THOMAS , DUFRÊNE ERIC , LELARGE‐TROUVERIE CAROLINE , DAMESIN CLAIRE 
Published: October 2010

ABSTRACTTree‐ring δ13C is often interpreted in terms of intrinsic water‐use efficiency (WUE) using a carbon isotope discrimination model established at the leaf level. We examined whether intra‐ring δ13C could be used to assess variations in intrinsic WUE (Wg, the ratio of carbon assimilation and stomatal conductance to water) and variations in ecosystem WUE (Wt, the ratio of C assimilation and transpiration) at a seasonal scale. Intra‐ring δ13C was measured in 30‐ to 60‐µm‐thick slices in eight oak trees (Quercus petraea). Canopy Wg was simulated using a physiologically process‐based model. High between‐tree variability was observed in the seasonal variations of intra‐ring δ13C. Six trees showed significant positive correlations between Wg calculated from intra‐ring δ13C and canopy Wg averaged over several days during latewood formation. These results suggest that latewood is a seasonal recorder of Wg trends, with a temporal lag corresponding to the mixing time of sugars in the phloem. These six trees also showed significant negative correlations between photosynthetic discrimination Δ calculated from intra‐ring δ13C, and ecosystem Wt, during latewood formation. Despite the observed between‐tree variability, these results indicate that intra‐ring δ13C can be used to access seasonal variations in past Wt.
Physiological and morphological adaptations in relation to water use efficiency in Mediterranean accessions of Solanum lycopersicum
Authors: GALMÉS JERONI , CONESA MIQUEL ÀNGEL , OCHOGAVÍA JOAN MANUEL , PERDOMO JUAN ALEJANDRO , FRANCIS DAVID M. , RIBAS‐CARBÓ MIQUEL , SAVÉ ROBERT , FLEXAS JAUME , MEDRANO HIPÓLITO , CIFRE JOSEP 
Published: October 2010

ABSTRACTThe physiological traits underlying the apparent drought resistance of ‘Tomàtiga de Ramellet’ (TR) cultivars, a population of Mediterranean tomato cultivars with delayed fruit deterioration (DFD) phenotype and typically grown under non‐irrigation conditions, are evaluated. Eight different tomato accessions were selected and included six TR accessions, one Mediterranean non‐TR accession (NTRM) and a processing cultivar (NTRO). Among the TR accessions two leaf morphology types, normal divided leaves and potato‐leaf, were selected. Plants were field grown under well‐watered (WW) and water‐stressed (WS) treatments, with 30 and 10% of soil water capacity, respectively. Accessions were clustered according to the leaf type and TR phenotype under WW and WS, respectively. Correlation among parameters under the different water treatments suggested that potential improvements in the intrinsic water‐use efficiency (AN/gs) are possible without negative impacts on yield. Under WS TR accessions displayed higher AN/gs, which was not due to differences in Rubisco‐related parameters, but correlated with the ratio between the leaf mesophyll and stomatal conductances (gm/gs). The results confirm the existence of differential traits in the response to drought stress in Mediterranean accessions of tomato, and demonstrate that increases in the gm/gs ratio would allow improvements in AN/gs in horticultural crops.
The 13C/12C isotopic signal of day‐respired CO2 in variegated leaves of Pelargonium × hortorum
Authors: TCHERKEZ GUILLAUME , MAUVE CAROLINE , LAMOTHE MARLENE , LE BRAS CAMILLE , GRAPIN AGNES 
Published: October 2010

ABSTRACTIn leaves, although it is accepted that CO2 evolved by dark respiration after illumination is naturally 13C‐enriched compared to organic matter or substrate sucrose, much uncertainty remains on whether day respiration produces 13C‐depleted or 13C‐enriched CO2. Here, we applied equations described previously for mesocosm CO2 exchange to investigate the carbon isotope composition of CO2 respired by autotrophic and heterotrophic tissues of Pelargonium×hortorum leaves, taking advantage of leaf variegation. Day‐respired CO2 was slightly 13C‐depleted compared to organic matter both under 21% O2 and 2% O2. Furthermore, most, if not all CO2 molecules evolved in the light came from carbon atoms that had been fixed previously before the experiments, in both variegated and green leaves. We conclude that the usual definition of day respiratory fractionation, that assumes carbon fixed by current net photosynthesis is the respiratory substrate, is not valid in Pelargonium leaves under our conditions. In variegated leaves, total organic matter was slightly 13C‐depleted in white areas and so were most primary metabolites. This small isotopic difference between white and green areas probably came from the small contribution of photosynthetic CO2 refixation and the specific nitrogen metabolism in white leaf areas.
Auxin depletion in barley plants under high‐temperature conditions represses DNA proliferation in organelles and nuclei via transcriptional alterations
Authors: OSHINO TAKESHI , MIURA SHINYA , KIKUCHI SYUNSUKE , HAMADA KAZUKI , YANO KENTARO , WATANABE MASAO , HIGASHITANI ATSUSHI 
Published: October 2010

ABSTRACTMany plant species are susceptible to high‐temperature (HT) injury during reproductive development. We recently demonstrated that HT represses the expression of YUCCA auxin biosynthesis genes and reduces endogenous auxin in the developing anthers of barley and Arabidopsis. Here, we show that DNA proliferation in mitochondria, chloroplasts and nuclei of developing panicles is inhibited with increasing temperatures in barley. Following DNA proliferation suppression, terminal abnormalities were observed in the organelles of anther wall cells, including mitochondrial swelling and overdevelopment of chloroplasts. Comprehensive transcriptome analyses using both reproductive organs and vegetative tissues showed high and positive pairwise correlations between the expression profiles of auxin‐induced genes, DNA replication‐related genes and mitochondrial‐related genes. In contrast, the expression profiles of auxin‐repressed protein genes and photosynthesis‐/chloroplast‐related genes were negatively correlated with those of the previously mentioned genes. Under HT conditions, the former was repressed and the latter was up‐regulated in the developing panicles. Furthermore, application of exogenous auxin promoted the expression of DNA replication‐related genes under HT conditions, inducing anther cell proliferation. These suggest that compromised auxin biosynthesis/IAA level under HT condition results in nuclear and organellar DNA proliferation arrest due to co‐transcriptional alterations.
An in vitro model of pig liver xenotransplantation—pig complement is associated with reduced lysis of wild‐type and genetically modified pig cells
Authors: Hara Hidetaka , Campanile Nathalie , Tai Hao‐Chih , Long Cassandra , Ekser Burcin , Yeh Peter , Welchons Dan , Ezzelarab Mohamed , Ayares David , Cooper David K. C. 
Published: October 2010

Hara H, Campanile N, Tai H‐C, Long C, Ekser B, Yeh P, Welchons D, Ezzelarab M, Ayares D, Cooper DKC. An in vitro model of pig liver xenotransplantation—pig complement is associated with reduced lysis of wild‐type and genetically modified pig cells. Xenotransplantation 2010; 17: 370–378. © 2010 John Wiley & Sons A/S.Abstract: Background: After pig liver transplantation in humans, the graft will produce pig complement (C). We investigated in vitro the lysis of wild‐type (WT), α1,3‐galactosyltransferase gene‐knockout (GTKO), and CD46 transgenic (CD46) pig peripheral blood mononuclear cells (PBMC) caused by human anti‐pig antibodies (Abs) + pig C.Methods: Human serum IgM/IgG binding to WT and GTKO PBMC was determined by flow cytometry, and lysis of pig PBMC by a C‐dependent cytotoxicity assay using (i) human serum (human Abs + C), (ii) GTKO pig serum (anti‐Gal Abs + pig C), (iii) heat‐inactivated human serum (human Abs) + rabbit C, or (iv) human Abs + pig C (serum).Results: Binding of human IgM and IgG to GTKO PBMC was less than to WT PBMC (P < 0.05). In the presence of human Abs, lysis of WT and GTKO PBMC by rabbit C was 87 and 13%, respectively (WT vs. GTKO, P < 0.01), but was only 37 and 0.4% in the presence of pig C (WT vs. GTKO, P < 0.05). Human/rabbit C‐induced lysis was greater than pig C‐induced lysis for both WT and GTKO PBMC. CD46 pig PBMC reduced rabbit/human C‐ and pig C‐mediated lysis (P < 0.05).Conclusions: Pig livers, particularly from GTKO and CD46 pigs, are likely to have an immunologic advantage over other organs after transplantation into humans. In the absence of pig antibodies directed to human tissues, pig complement is unlikely to cause problems after liver xenotransplantation, especially if GTKO/CD46 pigs are used as the source of the livers.
Structure and dynamics of distinct fish assemblages in three reaches (upper, middle and lower) of an open tropical estuary in Brazil
Authors: Neves Leonardo M. , Teixeira Tatiana P. , Araújo Francisco G. 
Published: October 2010

AbstractWe collected fishes and environmental variables in three zones (upper, middle and lower) of a small open tropical estuary during flood tide. The aim was to test for differences in fish assemblages along a gradient from freshwater to marine waters and to detect any seasonal variation in fishes and environmental variables across these zones. A total of 111 species (18 in the upper, 50 in the middle and 66 in the lower estuary) were recorded, forming three distinct fish assemblages, with the family Eleotridae dominating in the upper, Gerreidae in the middle, and Sciaenidae in the lower estuary. Only two species (Geophagus brasiliensis in the upper and the middle zones, and Eucinostomus argenteus in the middle and the lower zones) composed more than 1% of the total number of individuals in more than a single zone. Short‐term (tidal) changes in salinity in the middle estuary were associated with different assemblages in the three estuarine zones, even in winter, when the differences in salinity are lowest between the middle and the lower zones. Seasonal variation in salinity was irrelevant, except in a protected sidewater lagoon in the middle estuary. Low salinity seasonal change may be related to the lack of seasonal variation in the structure of fish assemblages in all estuarine zones.