bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generalist foraging of pollinators: diet expansion at high density
Authors: Fontaine Colin , Collin Carine L. , Dajoz Isabelle 
Published: June 2008

Summary

Plant–pollinator interactions are crucial for the reproduction of most angiosperms. When faced with perturbations, plant–pollinator networks might be robust mainly due to the presence of highly generalist species. Perturbations can, in turn, affect how pollinators exploit their food sources and therefore their degree of generalization.
In particular, generalization of pollinators might vary with forager density. At high densities floral resources available in plant communities would be more rapidly depleted than at low densities. According to optimal foraging theory (OFT), this decrease in resources should lead to an increase in diet breadth.
We investigated the impact of pollinator density on diet breadth of Bombus terrestris. We recorded the individual foraging behaviour of bumblebees from eight colonies. They foraged in presence of either one or several conspecifics on experimental plant communities composed of five plant species. Diet breadth was calculated as the number of plant species visited, as well as by the Levins index. We analyzed the effect of forager density on diet breadth at both the individual and the colony levels.
We found that forager density affected degree of generalization at individual and colony levels. A more competitive environment increased individual generalization, as predicted by OFT, and decreased the variability in generalization across colonies. Moreover, we found that bumblebee size was positively related to the amplitude of diet breadth change.
Synthesis. Our study sheds light on an additional level of complexity of plant–pollinator systems, showing that pollinator diet breadth is a flexible trait which results from behavioural adaptation to resource availability. More generally, changes in foraging insects’ diet via competition for resources are likely to ensue from anthropogenic ecosystem disturbance and to impact upon the functioning of plant–pollinator networks.
Thermal acclimation of photosynthesis in black spruce [Picea mariana (Mill.) B.S.P.]
Authors: WAY DANIELLE A. , SAGE ROWAN F. 
Published: June 2008

ABSTRACTWe investigated the thermal acclimation of photosynthesis and respiration in black spruce seedlings [Picea mariana (Mill.) B.S.P.] grown at 22/14 °C [low temperature (LT)] or 30/22 °C [high temperature (HT)] day/night temperatures. Net CO2 assimilation rates (Anet) were greater in LT than in HT seedlings below 30 °C, but were greater in HT seedlings above 30 °C. Dark and day respiration rates were similar between treatments at the respective growth temperatures. When respiration was factored out of the photosynthesis response to temperature, the resulting gross CO2 assimilation rates (Agross) was lower in HT than in LT seedlings below 30 °C, but was similar above 30 °C. The reduced Agross of HT seedlings was associated with lower needle nitrogen content, lower ribulose 1·5‐bisphosphate carboxylase/oxygenase (Rubisco) maximum carboxylation rates (Vcmax) and lower maximum electron transport rates (Jmax). Growth treatment did not affect Vcmax : Jmax. Modelling of the CO2 response of photosynthesis indicated that LT seedlings at 40 °C might have been limited by heat lability of Rubisco activase, but that in HT seedlings, Rubisco capacity was limiting. In sum, thermal acclimation of Anet was largely caused by reduced respiration and lower nitrogen investments in needles from HT seedlings. At 40 °C, photosynthesis in LT seedlings might be limited by Rubisco activase capacity, while in HT seedlings, acclimation removed this limitation.
MYBL2 is a new regulator of flavonoid biosynthesis in Arabidopsis thaliana
Authors: Dubos Christian , Le Gourrierec José , Baudry Antoine , Huep Gunnar , Lanet Elodie , Debeaujon Isabelle , Routaboul Jean‐Marc , Alboresi Alessandro , Weisshaar Bernd , Lepiniec Loïc 
Published: June 2008

SummaryIn Arabidopsis thaliana, several MYB and basic helix‐loop‐helix (BHLH) proteins form ternary complexes with TTG1 (WD‐Repeats) and regulate the transcription of genes involved in anthocyanin and proanthocyanidin (PA) biosynthesis. Similar MYB‐BHLH‐WDR (MBW) complexes control epidermal patterning and cell fates. A family of small MYB proteins (R3‐MYB) has been shown to play an important role in the regulation of epidermal cell fates, acting as inhibitors of the MBW complexes. However, so far none of these small MYB proteins have been demonstrated to regulate flavonoid biosynthesis. The genetic and molecular analyses presented here demonstrated that Arabidopsis MYBL2, which encodes a R3‐MYB‐related protein, is involved in the regulation of flavonoid biosynthesis. The loss of MYBL2 activity in the seedlings of two independent T‐DNA insertion mutants led to a dramatic increase in the accumulation of anthocyanin. In addition, overexpression of MYBL2 in seeds inhibited the biosynthesis of PAs. These changes in flavonoid content correlate well with the increased level of mRNA of several structural and regulatory anthocyanin biosynthesis genes. Interestingly, transient expression analyses in A. thaliana cells suggested that MYBL2 interacts with MBW complexes in planta and directly modulates the expression of flavonoid target genes. These results are fully consistent with the molecular interaction of MYBL2 with BHLH proteins observed in yeast. Finally, MYBL2 expression studies, including its inhibition by light‐induced stress, allowed us to hypothesise a physiological role for MYBL2. Taken together, these results bring new insights into the transcriptional regulation of flavonoid biosynthesis and provide new clues and tools for further investigation of its developmental and environmental regulation.
Comparison of bacterial pellets and microbial markers for the estimation of the microbial nitrogen and amino acids flows from single flow continuous culture fermenters fed diets containing two‐stage olive cake
Authors: Molina‐Alcaide E. , Moumen A. , Martín‐García I. , Carro M. D. 
Published: June 2008

SummaryThe effects of using effluent bacteria (EB) and solid‐ (SAB) and liquid‐ (LAB) associated bacteria and diaminopimelic acid (DAPA) or purine bases (PB) and partially substituting alfalfa hay (AH) by a concentrate including olive cake on the microbial N flow (MNF) and amino acids (AA) flow were investigated with continuous culture fermenters fed AH and a mixture of AH and a concentrate containing barley grains and two‐stage olive cake (2:1 ratio) without (AHCO) or with polyethylene glycol (PEG) (AHCOP). The MNF was not different among diets with SAB or LAB (p = 0.302 and 0.203, respectively) and DAPA, but differed with PB (p = 0.021 and 0.014, respectively). With EB both markers detected similar differences, AHCOP showing a higher value (p < 0.05) than AH and AHCO. The MNF was higher (p < 0.001) with PB than DAPA. Daily flow of non‐essential AA was not different (p = 0.356) among diets but essential AA flow was higher (p < 0.05) for AH and AHCOP than for AHCO. The SAB presented lower (p < 0.05) total AA than LAB and higher total AA (p < 0.05) for diet AH than AHCO. The AA profile of EB was similar to that of LAB, but alanine and leucine were higher (p < 0.05) in EB than in LAB. Microbial contribution to AA flow was 45.4%, 55.6% and 58.1% for diets AH, AHCO and AHCOP respectively. With both markers, microbial AA flow was higher (p < 0.05) for diet AHCOP compared with AH (451 and 355 mg/day, respectively), but not different (p > 0.05) for AHCOP and AHCO (389 mg/day). The results would indicate that olive cake could be used in the practical feeding of small ruminants without negatively affecting microbial AA N supply.
Carriage ofCandidaspecies in oral cavities of HIV infected patients in South India
Authors: Girish Kumar C. P. , Menon Thangam , Rajasekaran S. , Sekar B. , Prabu D. 
Published: June 2008

SummaryFifty‐four patients with human immunodeficiency virus (HIV) infection were studied to assess the load of oral carriage ofCandidaspp. The mean oralCandidacarriage density (30 305.93 ± 56 643.93 CFU ml−1) in HIV patients was significantly higher than that seen in the control population (93.48 ± 358.48 CFU ml−1;P = 0.000). The meanCandidaload in HIV patients with oral thrush (46 591.43 ± 65 002.57 CFU ml−1) was significantly higher than in the HIV subjects without oral thrush (306.32 ± 699.50 CFU ml−1;P = 0.000). Non‐C. albicans Candidaspecies (56%) were more predominant than theC. albicans(44%) isolates. 25S rDNA PCR analysis ofC. albicansrevealed preponderance of genotype A strains. Interestingly, 42.6% of rinse specimens grew multipleCandidaspecies, with the combination ofC. albicansandC. krusei(39.1%) being the most frequent.
Preoperative evaluation of hepatic functional reserve by converted ICGR15 calculated from 99mTc‐GSA scintigraphy
Authors: Kawamura Hideki , Kamiyama Toshiya , Nakagawa Takahito , Nakanishi Kazuaki , Yokoo Hideki , Tahara Munenori , Kamachi Hirofumi , Toi Hirofumi , Matsushita Michiaki , Todo Satoru 
Published: June 2008

AbstractBackground and Aim:  Conversion of data from technetium 99 m diethylenetriaminepentaacetic acid galactosyl human serum albumin (99mTc‐GSA) scintigraphy to ICGR15 (indocyanin green retention at 15 min) is an easy and convenient method for obtaining parameters to determine the appropriate and safe extent of liver resection. We investigated a conversion method which also accounts for LHL15 (receptor index: uptake ratio of the liver to the liver plus heart at 15 min) and HH15 (blood clearance index: uptake ratio of the heart at 15 min to that at 3 min) characteristics.Methods:  Cases included 282 patients undergoing hepatic resection following 99mTc‐GSA scintigraphy and an ICG tolerance test. Degree of liver dysfunction was classified as A, B, or C according to criteria of the Liver Cancer Study Group of Japan.Results:  HH15 demonstrated a larger distribution in patients with liver damage A, while LHL15 demonstrated a larger distribution in patients with liver damage B. In liver damage A, the conversion formula ICGR15 = 87.0–79.6 × LHL15 was obtained, and in liver damage B, the conversion formula ICGR15 = −23.3 + 72.4 × HH15 was obtained, and correlation with ICGR15 was higher (r = 0.61, P < 0.0001) than when the data were not segregated by liver damage severity. Furthermore, postoperative hyperbilirubinemia significantly occurred in cases where both ICGR15 and converted ICGR15 were high.Conclusions:  Conversion models based on data segregated by severity of liver damage were more closely correlated with ICGR15 than conversion models not based on segregated data. By using this converted ICGR15, preoperative estimation of hepatic functional reserve can become more reliable.
Huang‐lian‐jie‐du‐tang, a traditional Chinese medicine prescription, induces cell‐cycle arrest and apoptosis in human liver cancer cells in vitro and in vivo
Authors: Hsu Ya‐Ling , Kuo Po‐Lin , Tzeng Tz‐Fei , Sung Shu‐Chiao , Yen Ming‐Hong , Lin Liang‐Tzung , Lin Chun‐Ching 
Published: June 2008

AbstractBackground and Aim:  Huang‐lian‐jie‐du‐tang (HLJDT; Japanese name, oren‐gedoku‐to) is a traditional Chinese medicine prescription known to possess anti‐inflammatory activity. Our study reports here for the first time the anticancer effect of HLJDT in two human liver cancer cell lines, Hep G2 and PLC/PRF/5.Methods:  Inhibition of cell proliferation by HLJDT was measured by sodium 3′‐(1‐(phenylamino‐carbonyl)‐3,4‐tetrazolium)‐bis(4‐methoxy‐6‐nitro) benzene‐sulfonic acid hydrate (XTT) assay. Clonogenic assay was used to elucidate the possible differences in long‐term effects of HLJDT on human liver cancer cells. Cell cycle distribution was determined by flow cytometry. Apoptosis was detected using electrophoresis and terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate nick endlabeling (TUNEL) assay. Protein expressions were determined by immunoblot assay. The activity of nuclear factor–kappa B (NF‐κB) was determined by Trans‐AM ELISA kit. In vivo tumor activity was assessed by xenograft study.Results:  HLJDT significantly increased the expression of inactivated phospho‐Cdc2 and phospho‐Cdc25C, and decreased the levels of cyclin A, cyclin B1, Cdc2, and Cdc25C, thereby contributing to cell‐cycle arrest. HLJDT increased the expression of Bax and Bak, but decreased the level of Bcl‐2 and Bcl‐XL, and subsequently triggered the mitochondrial apoptotic pathway. In addition, HLJDT also inhibited cell‐survival signaling by enhancing the amount of IκBα in the cytoplasm, reducing the level and activity of NF‐κB in the nucleus, and subsequently attenuating the expression of Bcl‐XL in Hep G2 and PLC/PRF/5 cells. The inhibitory effect mediated by HLJDT on cell growth was also demonstrated in a nude mouse model, in which the liver cancer cells induced tumor xenograft shrank considerably following treatment with HLJDT.Conclusions:  Taken together, these results suggest a potential anticancer effect of HLJDT against human liver cancer cells.
Plant–soil feedbacks: a meta‐analytical review
Authors: Kulmatiski Andrew , Beard Karen H. , Stevens John R. , Cobbold Stephanie M. 
Published: June 2008

AbstractPlants can change soil biology, chemistry and structure in ways that alter subsequent plant growth. This process, referred to as plant–soil feedback (PSF), has been suggested to provide mechanisms for plant diversity, succession and invasion. Here we use three meta‐analytical models: a mixed model and two Bayes models, one correcting for sampling dependence and one correcting for sampling and hierarchical dependence (delta‐splitting model) to test these hypotheses. All three models showed that PSFs have medium to large negative effects on plant growth, and especially grass growth, the life form for which we had the most data. This supports the hypothesis that PSFs, through negative frequency dependence, maintain plant diversity, especially in grasslands. PSFs were also large and negative for annuals and natives, but the delta‐splitting model indicated that more studies are needed for these results to be conclusive. Our results support the hypotheses that PSFs encourage successional replacements and plant invasions. Most studies were performed using monocultures of grassland species in greenhouse conditions. Future research should examine PSFs in plant communities, non‐grassland systems and field conditions.
Host‐specificity of environmentally transmitted Mycoplasma‐like isopod symbionts
Authors: Fraune Sebastian , Zimmer Martin 
Published: June 2008

SummaryMycoplasms are known as pathogens of economic and medical interest in plants, animals and man. Here, we show a positive correlation between the presence of Mycoplasma‐like symbionts in their isopod hosts and survivorship on low‐quality food. Most isopods that survived feeding on a cellulose‐based low‐quality diet for 90 days harboured ‘Candidatus Hepatoplasma’ in their midgut glands, while those that died within 90 days mostly either harboured no or other bacterial symbionts. We detected ‘Candidatus Hepatoplasma’ in all but one of the examined species of terrestrial isopods from different habitats and locations, suggesting an evolutionarily ancient association between terrestrial isopods and their Mycoplasma‐like symbionts. Phylogenetic analyses clustered symbionts from different populations of the same isopod species together, and clearly distinguished between symbionts of different isopod species, indicating host‐specificity of ‘Candidatus Hepatoplasma’, although a previous study provided evidence for environmental symbiont transmission. Nonetheless, horizontal exchange of symbionts between species may have been possible in evolutionary earlier stages, as suggested by only limited congruency of phylogenetic trees of hosts and symbionts. Another symbiont, ‘Candidatus Hepatincola porcellionum’, was only detected in midgut glands of the most terrestrial tribe of isopods (Crinocheta), suggesting an evolutionarily younger host–symbiont association. This symbiont proved to be negatively correlated with host longevity, even on high‐quality food.
Family Relationships among Immigrants and Majority Members in the Netherlands: The Role of Acculturation
Authors: Arends‐Tóth Judit , Van de Vijver Fons J.R. 
Published: June 2008

This study examined the nature and size of differences in family relationships in five cultural groups in the Netherlands (Dutch mainstreamers, and Turkish, Moroccan, Surinamese, and Antillean immigrants). In order to get a better insight into the differences in family relationships, a distinction was made between family values and family ties. Family values refer to obligations and beliefs about family relationships whereas family ties involve more behavior‐related relational aspects. Results confirmed that the cultural differences in mean scores between immigrants and majority members were larger for family values than for family ties. Individual background variables had a much stronger association with family values than with family ties. In addition, first‐generation immigrants had more traditional family values and reported stronger family ties than did Dutch mainstreamers. Second‐generation immigrants had more traditional family values than Dutch mainstreamers but they did not report stronger family ties. In conclusion, the distinction between family values and family ties as different expressions of family relationships is highly relevant in an acculturation context, because cultural differences between the various immigrant groups and the mainstream group are not the same for values and ties, and acculturative changes are different for both.On se penche dans cette étude sur les relations familiales, leur nature et leurs différences dans cinq groupes culturels des Pays‐Bas (Hollandais de souche et immigrants turcs, marocains, surinamiens et antillais). Pour accéder à une meilleure appréhension des différences dans les relations familiales, on a opéré une distinction entre les valeurs et les liens familiaux. Les valeurs familiales font référence aux obligations et aux croyances concernant les relations familiales alors que les liens familiaux touchent des aspects relationnels plus comportementaux. Les résultats confirment que les différences culturelles (estimées au niveau des moyennes) entre les immigrants et les membres de la majorité de la population sont plus nettes pour les valeurs que pour les liens familiaux. Le fond culturel des individus est plus fortement associé aux valeurs qu’aux liens familiaux. De plus, les migrants de première génération présentent davantage de valeurs familiales traditionnelles et témoignent de liens familiaux plus forts que ceux des Hollandais de souche. Les migrants de seconde génération ont également plus de valeurs familiales traditionnelles que les Hollandais de souche, mais pas de liens familiaux plus étroits. Disons pour conclure que distinguer valeurs et liens familiaux comme étant des expressions différentes des relations en famille est tout à fait pertinent dans un contexte d’acculturation puisque les différences culturelles entre les divers groupes de migrants et les autochtones ne sont pas identiques pour les valeurs et les liens et que l’impact dûà l’acculturation n’est pas le même dans les deux cas.
Employability and Employees’ Well‐Being: Mediation by Job Insecurity1
Authors: Cuyper Nele De , Bernhard‐Oettel Claudia , Berntson Erik , Witte Hans De , Alarco Barbara 
Published: June 2008

The current study's aims are twofold: first, we investigate the relationship between employability and both work‐related (engagement) and general (life satisfaction) well‐being. Second, we study how employability may be relevant in times of high job insecurity. Specifically, we hypothesise (1) a positive relationship between employability and employees’ well‐being, (2) a negative relationship between employability and job insecurity, and (3) a negative relationship between job insecurity and employees’ well‐being, so that (4) job insecurity mediates the relationship between employability and employees’ well‐being. Results based on a sample of 559 respondents from divisions of seven Belgian organisations support our hypotheses. We conclude that employability may be a means to secure one's labour market position, rather than a means to cope with job insecurity.Les objectifs de cette étude sont doubles: nous étudions d’abord la relation entre l’employabilité et à la fois le bien‐être relatif au travail (implication) et le bien‐être global (la satisfaction provenant de l’existence). Ensuite, nous nous interrogeons sur la pertinence de l’employabilité en période de grande insécurité professionnelle. Plus précisément, nous posons les hypothèses 1) d’une relation positive entre l’employabilité et le bien‐être des employés, 2) d’une relation négative entre l’employabilité et l’insécurité professionnelle et 3) d’une relation négative entre l’insécurité professionnelle et le bien‐être des salariés, si bien que 4) l’insécurité professionnelle régule la relation entre l’employabilité et le bien‐être des salariés. Les résultats issus d’un échantillon de 559 répondants provenant de départements de sept organisations belges confortent nos hypothèses. On conclut que l’employabilité peut être une façon de sécuriser sa situation sur le marché du travail plutôt qu’un moyen pour affronter l’insécurité professionnelle.
Work Engagement in Japan: Validation of the Japanese Version of the Utrecht Work Engagement Scale
Authors: Shimazu A. , Schaufeli W.B. , Kosugi S. , Suzuki A. , Nashiwa H. , Kato A. , Sakamoto M. , Irimajiri H. , Amano S. , Hirohata K. , Goto R. , Kitaoka‐Higashiguchi K. 
Published: June 2008

The purpose of this study was to validate the Japanese version of the Utrecht Work Engagement Scale (UWES‐J). Employees from three independent samples completed the questionnaire (total N= 2,334). Confirmatory factor analyses using the multiple‐group method revealed that, instead of the original three‐factor model, a one‐factor model that assumes that all engagement items load on one single factor fitted the data. Moreover, the one‐factor structure was invariant across all three samples. Internal consistency of the scale was sufficiently high (α= .92) and the test–retest reliability with an interval of two months was .66. A series of second‐order confirmatory factor analyses to examine construct validity confirmed the hypothesised model, indicating that work engagement was positively related to job satisfaction whereas it was negatively related to strain and burnout. However, as in previous studies, professional efficacy, a component of burnout, loaded on the engagement factor. These results, in general, suggest the reliability (internal consistency and stability), factorial invariance, and construct validity of the UWES‐J in three independent samples.Cette étude avait pour objectif de valider la version japonaise de l’Echelle d’Implication au Travail d’Utrecht (UWES‐J). 2,334 salariés provenant de trois échantillons indépendants ont rempli le questionnaire. Une analyse factorielle confirmatoire faisant appel à la méthode des groupes multiples a montré que le modèle originel en trois facteurs devait laisser la place à un modèle unifactoriel puisque tous les items d’implication étaient saturés sur un unique facteur qui rendait compte à lui seul des données. En outre, la structure monofactorielle restait identique à elle‐même sur les trois échantillons. La consistance interne de l’échelle était suffisamment élevée (α= .92) et la fidélité test‐retest après une période de deux mois était de .66. Une série d’analyses factorielles confirmatoires de second ordre destinées àétudier la validité de construction ont confirmé le modèle hypothétique, indiquant que l’implication dans le travail était en corrélation positive avec la satisfaction professionnelle tandis qu’elle était en relation négative avec la tension nerveuse et le burnout. Comme dans des travaux antérieurs, l’efficacité professionnelle, une composante du burnout, était saturée dans le facteur d’implication. Ces résultats, vont dans le sens de la fidélité (consistance interne et stabilité), de la solidité factorielle et de la validité de construction de l’UWES‐J dans ces trois échantillons indépendants.