bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complementarity effects drive positive diversity effects on biomass production in experimental benthic diatom biofilms
Authors: Vanelslander Bart , De Wever Aaike , Van Oostende Nicolas , Kaewnuratchadasorn Pattaratjit , Vanormelingen Pieter , Hendrickx Frederik , Sabbe Koen , Vyverman Wim 
Published: July 2009

Summary1. Positive effects of species diversity on ecosystem functioning have often been demonstrated in ‘macrobial’ communities. This relation and the responsible mechanisms are far less clear for microbial communities. Most experimental studies on microorganisms have used randomly assembled communities that do not resemble natural communities. It is therefore difficult to predict the consequences of realistic, non‐random diversity loss.2. In this study, we used naturally co‐occurring diatom species from intertidal mudflats to assemble communities with realistically decreasing diversity and analysed the effect of non‐random species loss on biomass production.3. Our results demonstrate a highly positive biodiversity effect on production, with mixtures outperforming the most productive component species in more than half of the combinations. These strong positive diversity effects could largely be attributed to positive complementarity effects (including both niche complementarity and facilitation), despite the occurrence of negative selection effects which partly counteracted the positive complementarity effects at higher diversities.4. Facilitative interactions were, at least in part, responsible for the higher biomass production. For one of the species,Cylindrotheca closterium, we show its ability to significantly increase its biomass production in response to substances leaked into the culture medium by other diatom species. In these conditions, the species drastically reduced its pigment concentration, which is typical for mixotrophic growth.5. Synthesis. We show that both species richness and identity have strong effects on the biomass production of benthic diatom biofilms and that transgressive overyielding is common in these communities. In addition, we show mechanistic evidence for facilitation which is partly responsible for enhanced production. Understanding the mechanisms by which diversity enhances the performance of ecosystems is crucial for predicting the consequences of species loss for ecosystem functioning.
Onset of algal endosymbiont specificity varies among closely related species of Acropora corals during early ontogeny
Authors: ABREGO DAVID , VAN OPPEN MADELEINE J. H. , WILLIS BETTE L. 
Published: July 2009

AbstractJuveniles of a number of corals with horizontal transmission of dinoflagellate endosymbionts naturally acquire and maintain Symbiodinium types that differ from those found in adult populations. However, the duration of this early period of symbiont flexibility and successional changes leading to dominance by the characteristic adult (homologous) type are unknown. To document natural succession of Symbiodinium types within juvenile corals, we monitored Symbiodinium communities in juveniles of Acropora tenuis and Acropora millepora for 3.5 years. Juveniles originating from one of three reef populations, characterized by differing adult coral‐Symbiodinium associations, were raised in a common environment. In four out of five cases, juveniles became dominated initially by a nonhomologous adult type. Changes in Symbiodinium communities associated with A. tenuis juveniles led to the establishment of the adult homologous association at ∼3.5 years of age. These changes were not linked to the onset of reproductive maturity, but may be linked to micro‐environmental changes associated with vertical growth of juvenile corals. We hypothesize that fine‐tuning of specificity mechanisms takes place during ontogeny in A. tenuis, leading to the eventual establishment of the adult homologous association. However, Symbiodinium communities in A. millepora juveniles did not change significantly over the 3.5 years, potentially reflecting (i) lack of specificity, (ii) more than a 3.5‐year delay in the onset of specificity, or (iii) lack of availability of the adult Symbiodinium type. This study demonstrates that juvenile corals may survive for extended periods of time with nonhomologous Symbiodinium types and that closely related species of Acropora differ in the timing of the onset of specificity for algal symbionts.
Reverse sex‐biased philopatry in a cooperative bird: genetic consequences and a social cause
Authors: BERG E. C. , EADIE J. M. , LANGEN T. A. , RUSSELL A. F. 
Published: July 2009

AbstractThe genetic structure of a group or population of organisms can profoundly influence the potential for inbreeding and, through this, can affect both dispersal strategies and mating systems. We used estimates of genetic relatedness as well as likelihood‐based methods to reconstruct social group composition and examine sex biases in dispersal in a Costa Rican population of white‐throated magpie‐jays (Calocitta formosa, Swainson 1827), one of the few birds suggested to have female‐biased natal philopatry. We found that females within groups were more closely related than males, which is consistent with observational data indicating that males disperse upon maturity, whereas females tend to remain in their natal territories and act as helpers. In addition, males were generally unrelated to one another within groups, suggesting that males do not disperse with or towards relatives. Finally, within social groups, female helpers were less related to male than female breeders, suggesting greater male turnover within groups. This last result indicates that within the natal group, female offspring have more opportunities than males to mate with nonrelatives, which might help to explain the unusual pattern of female‐biased philopatry and male‐biased dispersal in this system. We suggest that the novel approach adopted here is likely to be particularly useful for short‐term studies or those conducted on rare or difficult‐to‐observe species, as it allows one to establish general patterns of philopatry and genetic structure without the need for long‐term monitoring of identifiable individuals.
Z‐scores and the birthweight paradox
Authors: Schisterman Enrique F. , Whitcomb Brian W. , Mumford Sunni L. , Platt Robert W. 
Published: July 2009

SummaryInvestigators have long puzzled over the observation that low‐birthweight babies of smokers tend to fare better than low‐birthweight babies of non‐smokers. Similar observations have been made with regard to factors other than smoking status, including socio‐economic status, race and parity. Use of standardised birthweights, or birthweight z‐scores, has been proposed as an approach to resolve the crossing of the curves that is the hallmark of the so‐called birthweight paradox. In this paper, we utilise directed acyclic graphs, analytical proofs and an extensive simulation study to consider the use of z‐scores of birthweight and their effect on statistical analysis. We illustrate the causal questions implied by inclusion of birthweight in statistical models, and illustrate the utility of models that include birthweight or z‐scores to address those questions.Both analytically and through a simulation study we show that neither birthweight nor z‐score adjustment may be used for effect decomposition. The z‐score approach yields an unbiased estimate of the total effect, even when collider‐stratification would adversely impact estimates from birthweight‐adjusted models; however, the total effect could have been estimated more directly with an unadjusted model. The use of z‐scores does not add additional information beyond the use of unadjusted models. Thus, the ability of z‐scores to successfully resolve the paradoxical crossing of mortality curves is due to an alteration in the causal parameter being estimated (total effect), rather than adjustment for confounding or effect decomposition or other factors.
Association of the toll‐like receptor 2 A‐16934T promoter polymorphism with severe atopic dermatitis
Authors: Oh D.‐Y. , Schumann R. R. , Hamann L. , Neumann K. , Worm M. , Heine G. 
Published: July 2009

Background:  Atopic dermatitis (AD) is a chronic inflammatory skin disease with a multifactorial pathogenesis and increasing incidence in the Western world. A genetically determined defective function of pattern recognition receptors such as toll‐like receptors (TLRs) has been proposed as a candidate mechanism in the pathogenesis of AD.Aim:  To study the impact of genetic predisposition of five genes encoding for pattern recognition‐related molecules for the phenotype of AD.Methods:  We examined nine different single‐nucleotide polymorphism (SNP) frequencies in the genes encoding TLR1, ‐2, ‐4, ‐9 and the adapter molecule TIRAP by PCR with subsequent melting curve analysis in a case/control cohort of 136 adult AD patients and 129 age and gender matched non‐atopic, healthy individuals. TLR2‐expression and ‐function in cells from genotyped individuals were analysed.Results:  For the SNPs examined, similar genotype frequencies were found in both groups. In a subgroup of patients suffering from severe AD (SCORAD >50), a significantly increased representation of the A‐allele in position –16934 of the tlr2 gene was present (P = 0.004). Constitutive tlr2 mRNA expression in peripheral monocytes was independent of this tlr2 promoter SNP. Stimulation assays indicated that IL‐6, but not TNF‐α secretion following TLR2 stimulation is reduced in homozygous tlr2‐16934‐A allele carriers.Conclusion:  These data indicate that TLR2 is relevant for the phenotype of severe AD in adults.
Effect of natural seasonal pollen exposure and repeated nasal allergen provocations on elevation of exhaled nitric oxide
Authors: Bergmann‐Hug K. , Wirth R. , Henseler M. , Helbling A. , Pichler W. J. , Schnyder B. 
Published: July 2009

Background:  Exhaled nitric oxide (FENO) is a marker for allergic airway inflammation. We wondered whether in patients with intermittent allergic rhinitis only (i) natural pollen exposure and (ii) artificial pollen exposure by repeated nasal allergen provocations may lead to an elevation of FENO.Methods:  In two prospective studies, we compared the FENO of nonatopic controls with the FENO of nonasthmatic individuals with mild intermittent rhinitis to tree and/or grass pollen. Study I: 13 atopic individuals and seven controls had measurements of FENO, blood eosinophils and eosinophilic cationic protein (ECP) before, during and after pollen season. Study II: 16 atopic individuals and 12 controls had nasal allergen provocations on four following days out of pollen season, with daily measurements of FENO before, 2 and 6 h after provocation, and determination of blood eosinophils, ECP and FEV1 at baseline, on days 5 and 10–12.Results:  Natural pollen exposure (study I) caused a significant elevation of FENO in allergic individuals. Nasal allergen provocations (study II) did not elicit a statistically significant rise neither of FENO nor of blood eosinophils between baseline and day 5. However, a subgroup of four individuals with a rise of blood eosinophils during nasal allergen provocations showed also a rise of FENO.Conclusions:  We suppose that in allergic rhinitis a concomitant reaction of the bronchial system is dependent on a strong local inflammation leading to a generalized immune stimulation.
How much specific is the association between hymenoptera venom allergy and mastocytosis?
Authors: Bonadonna P. , Zanotti R. , Pagani M. , Caruso B. , Perbellini O. , Colarossi S. , Olivieri E. , Dama A. , Schiappoli M. , Senna G. , Antico A. , Passalacqua G. 
Published: July 2009

Background: The preferential association of mastocytosis with hymenoptera sting reactions is well known, but there is no data on the prevalence of clonal mast cell disorders in subjects with severe systemic reactions due to foods or drugs.Methods: Patients with food‐ or drug‐induced severe systemic reactions, including anaphylaxis, and increased serum tryptase were studied for the presence of mastocytosis, and compared with a population of patients with hymenoptera allergy. The aetiological role of foods or drugs was assessed according to current recommendations. Systemic reactions were graded in severity according to the procedure described by Mueller. Serum tryptase was considered increased if the level was >11.4 ng/ml. Subjects with increased tryptase had dermatological evaluation and Bone marrow(BM) aspirate‐biopsy, which included histology/cytology, flow cytometry and detection ofKITmutations.Results: A total of 137 subjects (57 male, mean age 42 years) were studied. Of them, 86 proved positive for drugs and 51 for foods. Overall, out of 137 patients, only nine (6.6%) had a basal tryptase >11.4 ng/ml, and only two (1.5%) were diagnosed with mastocytosis. This was clearly different from patients with hymenoptera allergy, where 13.9% had elevated tryptase and 11.1% had a clonal mast cell disorder.Conclusion: The association of clonal mast cell disorders with hymenoptera allergy seems to be more specific than that with food‐ or drug‐induced systemic reactions.
No effects of a synonymous variant within the CD59 gene on its protein product in duodenal biopsies of coeliac individuals
Authors: Scerri C. A. , Xuereb‐Anastasi A. , Vidal C. 
Published: July 2009

AbstractA novel rare variant within the CD59 gene was linked with coeliac disease in a family with high incidence of disease. Functional analyses of this variant were performed using complementary DNA analysis and protein analysis in paraffin‐embedded duodenal biopsies from affected individuals and controls. No effects on pre‐mRNA or size of linear protein were observed, although these results do not exclude the possible effects of this variant on co‐translational protein folding.
Characterization of a novel HLA‐A*11 allele in a cord blood unit by sequence‐based typing: HLA‐A*1141
Authors: Manfroi Silvia , Buffi Ornella , Amadei Michela , Bontadini Andrea , Nesci Sonia 
Published: July 2009

AbstractThe new allele HLA‐A*1141 differs from HLA‐A*110101 at the codon 120 by a substitution at the first nucleotide (GGC to CGC).
Influence of heritable social status on daily gain and feeding pattern in pigs
Authors: Chen C.Y. , Misztal I. , Tsuruta S. , Herring W.O. , Holl J. , Culbertson M. 
Published: July 2009

SummarySocial genetic relationships among average daily gain (ADG, g) and feeding pattern as daily feed intake (DFI, g), daily feeder occupation time (DOT, min), and daily feeding rate (DFR, g/min) were examined using records of 547 Duroc boars. Single‐trait animal models were fitted differently for traits, including or excluding social genetic effects, random or fixed pen effects, with covariates of pen sizes and initial age or weight. Genetic parameters for feeding pattern were estimated by restricted maximum likelihood. Six sets of parameters for ADG based on literature estimates were used due to difficulty in untangling confounded effects. Positive and negative signs of direct‐social genetic covariances were interpreted as heritable cooperation and competition, respectively. Dominant and subordinate pigs were classified as pigs with higher direct and social genetic values, respectively. Correlations of estimated breeding values between ADG and DFI, DOT, and DFR were 0.46, 0.04 and 0.29 for dominant pigs. Given heritable cooperation, subordinate pigs tended to increase feed intake (r = 0.36) and eating rate (r = 0.25). Given heritable competition, subordinate pigs fail to compensate for the competition with decreased feed intake (r = −0.53). The slow eating rate (r = −0.31) was considered as a consequence of eating during less busy hour of feeding.
Selection of locations of knots for linear splines in random regression test‐day models
Authors: Jamrozik J. , Bohmanova J. , Schaeffer L.R. 
Published: July 2009

SummaryUsing spline functions (segmented polynomials) in regression models requires the knowledge of the location of the knots. Knots are the points at which independent linear segments are connected. Optimal positions of knots for linear splines of different orders were determined in this study for different scenarios, using existing estimates of covariance functions and an optimization algorithm. The traits considered were test‐day milk, fat and protein yields, and somatic cell score (SCS) in the first three lactations of Canadian Holsteins. Two ranges of days in milk (from 5 to 305 and from 5 to 365) were taken into account. In addition, four different populations of Holstein cows, from Australia, Canada, Italy and New Zealand, were examined with respect to first lactation (305 days) milk only. The estimates of genetic and permanent environmental covariance functions were based on single‐ and multiple‐trait test‐day models, with Legendre polynomials of order 4 as random regressions. A differential evolution algorithm was applied to find the best location of knots for splines of orders 4 to 7 and the criterion for optimization was the goodness‐of‐fit of the spline covariance function. Results indicated that the optimal position of knots for linear splines differed between genetic and permanent environmental effects, as well as between traits and lactations. Different populations also exhibited different patterns of optimal knot locations. With linear splines, different positions of knots should therefore be used for different effects and traits in random regression test‐day models when analysing milk production traits.
Identification of a Cucumber mosaic virus Isolate from Passiflora edulis in Southern Italy and Validation of Subgroup Identification by In Silico Restriction Fragment Length Polymorphism
Authors: Parrella Giuseppe , Sorrentino Daniela 
Published: July 2009

AbstractReverse transcription‐polymerase chain reaction (RT‐PCR), comparison of nucleotide sequences and in silico restriction enzyme analysis were used to identify for the first time in Italy an isolate of Cucumber mosaic virus (CMV), belonging to subgroup II, from a disease‐affected passion fruit (Passiflora edulis) plant. We showed also that CMV sequences obtained by RT‐PCR with primers designed to a conserved region of the 3′ end of the CMV coat protein gene, combined with computer‐based restriction analysis of sequences stored in databases, can be a very powerful method for identification or validation for CMV subgroups. An accurate disease diagnosis requires reliability, high reproducibility and high throughput of the chosen method. With the proposed in silico approach, we managed to identify and validate with safety the identification of the three CMV subgroups (IA, IB and II). Isolates of CMV can be reliably identified by this method and thus it should be considered as a powerful tool for both epidemiological and management aspects of the CMV–plant interactions. The potentialities of this diagnostic method are discussed and compared with those of conventional methods.
A 10‐kDa acyl‐CoA‐binding protein (ACBP) from Brassica napus enhances acyl exchange between acyl‐CoA and phosphatidylcholine
Authors: Yurchenko Olga P. , Nykiforuk Cory L. , Moloney Maurice M. , Ståhl Ulf , Banaś Antoni , Stymne Sten , Weselake Randall J. 
Published: July 2009

SummaryThe gene encoding a 10‐kDa acyl‐CoA‐binding protein (ACBP) from Brassica napus was over‐expressed in developing seeds of Arabidopsis thaliana. Biochemical analysis of T2 and T3 A. thaliana seeds revealed a significant increase in polyunsaturated fatty acids (FAs) (18:2cisΔ9,12 and 18:3cisΔ9,12,15) at the expense of very long monounsaturated FA (20:1cisΔ11) and saturated FAs. In vitro assays demonstrated that recombinant B. napus ACBP (rBnACBP) strongly increases the formation of phosphatidylcholine (PC) in the absence of added lysophosphatidylcholine in microsomes from ΔYOR175c yeast expressing A. thaliana lysophosphatidylcholine acyltransferase (AthLPCAT) cDNA or in microsomes from microspore‐derived cell suspension cultures of B. napus L. cv. Jet Neuf. rBnACBP or bovine serum albumin (BSA) were also shown to be crucial for AthLPCAT to catalyse the transfer of acyl group from PC into acyl‐CoA in vitro. These data suggest that the cytosolic 10‐kDa ACBP has an effect on the equilibrium between metabolically active acyl pools (acyl‐CoA and phospholipid pools) involved in FA modifications and triacylglycerol bioassembly in plants. Over‐expression of ACBP during seed development may represent a useful biotechnological approach for altering the FA composition of seed oil.
Vagus nerve stimulation induces changes in respiratory sinus arrhythmia of epileptic children during sleep
Authors: Zaaimi Boubker , Grebe Reinhard , Berquin Patrick , Wallois Fabrice 
Published: July 2009

SummaryPurpose:  This study analyzed the direct short‐term effect of vagus nerve stimulation (VNS) on respiratory sinus arrhythmia (RSA) in children with pharmacoresistant epilepsy.Methods:  RSA magnitude is calculated as the ratio between maximum and minimum heart rate for each respiratory cycle—before, during, and after the actual VNS period. In 10 children, changes in RSA magnitude were evaluated on polysomnographic recordings, including electrocardiography (ECG), electroencephalography (EEG), thoracoabdominal distension, nasal airflow, and VNS artifacts. Measurements during stimulation were compared with those at baseline, immediately preceding the VNS periods and individually for each patient.Result:  During VNS, respiratory frequency increased and respiratory amplitude decreased with a variable effect on cardiac activity. The coupling between heart rate and respiratory rate was disturbed and RSA magnitude decreased significantly in 6 of 10 children during VNS. These changes in RSA magnitude varied from one child to another. The observed changes for respiratory and cardiac activity were concomitant with changes in RSA but were not correlated.Conclusion:  Together with disorders of respiration, cardiac activity, and oxygen saturation (SaO2) described previously. VNS also modifies synchronization between cardiac and respiratory activity, resulting in poor optimization of oxygen delivery to tissues that can be regarded as an additive side effect, which should be considered in patients with already altered brain function. This interaction between the effects of VNS and potential autonomic nervous system (ANS) dysfunction already reported in epileptic patients should be considered to be potentially life‐threatening. In addition, evaluation of changes in respiratory parameters can also provide reliable markers for further evaluation of the effectiveness of VNS.