bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antimyeloma effects of arsenic trioxide are enhanced by melphalan, bortezomib and ascorbic acid
Authors: Campbell Richard A. , Sanchez Eric , Steinberg Jeffrey A. , Baritaki Stavroula , Gordon Melinda , Wang Cathy , Shalitin Dror , Chen Haiming , Pang Shen , Bonavida Benjamin , Said Jonathan , Berenson James R. 
Published: June 2007

SummaryArsenic trioxide (ATO) induces apoptosis of malignant plasma cells through multiple mechanisms, including inhibition of DNA binding by nuclear factor kappa‐B, a key player in the development of chemoresistance in multiple myeloma (MM). This activity suggests that ATO may be synergistic when combined with other active antimyeloma drugs. To evaluate this, we examined the antimyeloma effects of ATO alone and in combination with bortezomib, melphalan and ascorbic acid (AA) both in vitro and in vivo using a severe combined immunodeficient (SCID)‐hu murine myeloma model. Marked synergistic antimyeloma effects were demonstrated when human MM Los Angeles xenograft IgG lambda light chain (LAGλ‐1) cells were treated in vitro with ATO and any one of these agents. SCID mice bearing human MM LAGλ‐1 tumours were treated with single‐agent ATO, bortezomib, melphalan, or AA, or combinations of ATO with either bortezomib or melphalan and AA. Animals treated with any of these drugs alone showed tumour growth and increases in paraprotein levels similar to control mice, whereas animals treated with ATO‐containing combinations showed markedly suppressed tumour growth and significantly reduced serum paraprotein levels. These in vitro and in vivo results suggest that addition of ATO to other antimyeloma agents may result in improved outcomes for patients with relapsed or refractory MM.
The effect of dispersal ability in winter and summer stoneflies on their genetic differentiation
Authors: YASICK ALISON L. , KREBS ROBERT A. , WOLIN JULIE A. 
Published: June 2007

Abstract 1. Plecopteran species disperse less than most other aquatic insects. Within stoneflies, members of different families vary in the degree of wing morphology and season of adult emergence.2. Dispersal limitations were tested to determine if there were increased differences among the nearby, Chagrin and Grand River populations in north‐eastern Ohio, by comparing genetic variation within the 16s rRNA region of mitochondrial DNA in two stoneflies. Allocapnia recta emerges in winter and often has rudimentary wings, and Leuctra tenuis emerges in summer with fully developed wings.3. There was significant genetic variability between the samples of A. recta from two adjacent rivers (FST = 0.20), but not between samples of L. tenuis (FST = 0.07).4. Distinct clades in A. recta were found to occur within the minimum spanning tree specific to the Chagrin River, which contributed to a significant difference in gene diversity between the two rivers. Haplotypes in L. tenuis appeared randomly distributed between the two rivers; however, nucleotide diversity was significantly less in samples from the Grand River.5. Shared haplotypes of both species illustrate the inter‐connectedness of the Chagrin and Grand River populations, and the lower genetic variability of L. tenuis between the two rivers is indicative of its greater dispersal capability.
Predation risk perception and food scarcity induce alterations of life‐cycle traits of the mosquito Culex pipiens
Authors: BEKETOV MIKHAIL A. , LIESS MATTHIAS 
Published: June 2007

Abstract 1. Predators may affect prey populations by direct consumption, and by inducing defensive reactions of prey to the predation risk. Food scarcity frequently has effects on the inducible defences of prey, but no consistent pattern of food–predation risk interaction is known.2. In this study the combined effect of food shortage and predation‐risk perception in larvae of the mosquito Culex pipiens was investigated. Water exposed to the aquatic predator bug Notonecta glauca was used as a source of predation intimidation. Mosquito larvae were reared in three different media containing either no predator cues or the cues of N. glauca that had been fed on either C. pipiens larvae or on Daphnia magna. Food was provided in favourable or limited amount for these set‐ups.3. The results showed that chemical cues from the predators fed with prey’s conspecifics caused a decreased survival, delayed pre‐imaginal development, and reduction in body size of emerged mosquitoes, whereas chemical cues from predators fed with D. magna caused only delayed development. Food scarcity significantly exacerbates the negative effect of the predator cues on pre‐imaginal development of C. pipiens. Effects of the cues on larval development and body size of imagoes are significantly stronger for females than for males.4. The present study suggests that when food is limited, predators can affect population dynamics of prey not only by direct predation, but also by inducing lethal and sublethal effects due to perception of risk imposed by chemical cues. To understand the effects of predators on mosquito population dynamics, environmental parameters such as food deficiency should be considered.
Increasing tolerance to Cry1Ac cotton from cotton bollworm, Helicoverpa armigera, was confirmed in Bt cotton farming area of China
Authors: LI GUO‐PING , WU KONG‐MING , GOULD FRED , WANG JIAN‐KANG , MIAO JIN , GAO XI‐WU , GUO YU‐YUAN 
Published: June 2007

Abstract 1. Changes in the frequency of Cry1Ac resistance genes and shifts in tolerance of cotton bollworm, Helicoverpa armigera, to the Cry1Ac toxin were assessed using bioassays of F1 and F2 offspring of isofemale lines from Anci County of Hebei Province (a multiple‐crop system including corn, soybean, peanut, and Bt cotton) and Xiajin County of Shandong Province (an intensive Bt cotton planting area) in Northern China during 2002–2005.2. A conservative analysis of the overall results indicated that there was a small increase in the frequency of major, non‐recessive resistance genes over time.3. The relative average development ratings [RADR – growth rate of a line on a Bt diet in proportion to the growth rate on a non‐Bt (NBT) diet] of the bollworm larvae in F1 tests increased significantly from year to year, indicating a gradual trend towards higher tolerance to Cry1Ac in the field populations.4. There were also significant positive correlations between RADR of the lines in the F1 generation and the RADR of their F2 offspring, indicating that the tolerance was genetically based.5. Quantitative genetic simulation analysis showed that resistance of H. armigera to Bt cotton in Xiajin could evolve to a high level in 11–15 years if no effective resistance management measures are carried out.
Factors influencing nitrogen and phosphorus excretion rates of fish in a shallow lake
Authors: VERANT MICHELLE L. , KONSTI MELISSA L. , ZIMMER KYLE D. , DEANS CARRIE A. 
Published: June 2007

Summary 1. Fish excretion can be an important source of nutrients in aquatic ecosystems. Nitrogen (N) and phosphorus (P) excretion rates are influenced by many factors, including fish diet, fish growth rate and fish size. However, the relative influence of these and other factors on community‐level excretion rates of fish is unknown.2. We used bioenergetics modeling to estimate excretion rates of eight fish species in a shallow, Minnesota (U.S.A.) lake over four months in both 2004 and 2005. Excretion rates of each species were summed for community‐level N and P excretion rates, as well as the N : P ratio of excretion. We then used a model‐selection approach to assess ability of independent variables to predict excretion rates, and to identify the most parsimonious model for predicting N : P excretion ratios and P and N excretion rates at the community scale. Predictive models were comprised of the independent variables water temperature and average fish density, fish size, fish growth rate, nutrient content of fish and nutrient content of fish diets at the community scale.3. Fish density and nutrient content of fish diets (either N or P) were the most parsimonious models for predicting both N and P excretion rates, and explained 96% and 92% of the variance in N and P excretion, respectively. Moreover, fish density and nutrient models had 1400‐fold more support for predicting N and 21‐fold more support for predicting P excretion relative to models based on fish density only. Water temperature, fish size, fish growth rates and nutrient content of fish showed little influence on excretion rates, and none of our independent variables showed a strong relationship with N : P ratios of excretion.4. Past work has focused on the importance of fish density as a driver of fish excretion rates on a volumetric basis. However, our results indicate that volumetric excretion rates at the community scale will also change substantially in response to changes in relative abundance of fish prey or shifts in relative dominance of planktivores, benthivores, or piscivores. Changes in community‐scale excretion rates will have subsequent influences on algal abundance, water clarity, and other ecosystem characteristics.
The effect of supplementary winter seed food on breeding populations of farmland birds: evidence from two large‐scale experiments
Authors: SIRIWARDENA GAVIN M. , STEVENS DANAË K. , ANDERSON GUY Q. A. , VICKERY JULIET A. , CALBRADE NEIL A. , DODD STEPHEN 
Published: June 2007

Summary

Low winter food availability is probably critical in the declines of many farmland bird species in Europe, leading to the implementation of ameliorative agri‐environment scheme options. To date, however, there has been no experimental test of the effectiveness of such options.
We report the results of two large‐scale, 3‐year, controlled experiments investigating the effects of supplementary winter seed provision on breeding farmland bird abundance. In each experiment, the use of winter feeding sites by birds was monitored and the availability of alternative, seed‐rich habitat in the surrounding area was measured. The Winter Food for Birds (WFFB) project also included variable levels of food provision. Breeding bird abundance was then monitored in experimental and control areas. The Bird Aid project targeted yellowhammer Emberiza citrinella L., corn bunting Emberiza calandra L. and tree sparrow Passer montanus L., while WFFB considered 11 species that used supplementary winter food.
Comparisons of trends in breeding abundance between experimental and control areas revealed little evidence for positive effects of feeding, but there was great variation in the use of feeding sites by each species, and therefore in the seed quantity birds received.
Declines for yellowhammer, robin and dunnock were less steep where more food was provided in WFFB areas (a fourfold difference in seed provision across 1·5 times the land area).
Analysing trends with respect to weight‐of‐use of winter food revealed significant, positive relationships for yellowhammer (both projects) and up to five other species, depending on the control terms applied. Thus, positive effects of feeding on population change depend on the effective supply of seed to the species of interest. The hypothesis that winter food is currently limiting the populations concerned is also supported.
Synthesis and applications. Effective winter food provision to farmland bird populations has the potential to halt, and perhaps to reverse, declines in abundance. In practice, this means that agri‐environment measures supplying significant quantities of winter food, such as stubbles preceded by low‐input cereals, should succeed in changing population trends if they provide resources at the times of greatest need and if there is sufficient uptake.
Co(i)‐ordinating defenses: NaCOI1 mediates herbivore‐ induced resistance in Nicotiana attenuata and reveals the role of herbivore movement in avoiding defenses
Authors: Paschold Anja , Halitschke Rayko , Baldwin Ian T. 
Published: June 2007

SummaryArabidopsis and tomato plants mutated in the F‐box protein COI1 mediating jasmonate (JA) responses are more susceptible to herbivores in laboratory trials, but the exact mechanisms of COI1‐mediated resistance are not known. We silenced COI1 by transformation with an inverted repeat construct (ir‐coi1) in Nicotiana attenuata, a plant the direct and indirect defenses of which against various herbivores have been well studied. ir‐coi1 plants are male sterile and impaired in JA‐elicited direct [nicotine, caffeoylputrescine and trypsin proteinase inhibitor (TPI) activity] and indirect (cis‐α‐bergamotene emission) defense responses; responses not elicited by JA treatment (ethylene production and flower TPI activity) were unaffected. Larvae of Manduca sexta, a common herbivore of N. attenuata, gained three times more mass feeding on ir‐coi1 than on wild‐type (WT) plants in glasshouse experiments. By regularly moving caterpillars to unattacked leaves of the same plant, we demonstrate that larvae on WT plants can grow and consume leaves as fast as those on ir‐coi1 plants, a result that underscores the role of COI1 in mediating locally induced resistance in attacked leaves, and the importance of herbivore movement in avoiding the induced defenses of a plant. When transplanted into native habitats in the Great Basin Desert, ir‐coi1 plants suffer greatly from damage by the local herbivore community, which includes herbivores not commonly found on N. attenuata WT plants. Choice assays with field‐grown plants confirmed the increased attractiveness of ir‐coi1 plants for both common and unusual herbivores. We conclude that NaCOI1 is essential for induced resistance in N. attenuata, and that ir‐coi1 plants highlight the benefits of herbivore movement for avoiding induced defenses.
RING‐H2 type ubiquitin ligase EL5 is involved in root development through the maintenance of cell viability in rice
Authors: Koiwai Hanae , Tagiri Akemi , Katoh Shizue , Katoh Etsuko , Ichikawa Hiroaki , Minami Eiichi , Nishizawa Yoko 
Published: June 2007

SummaryRice EL5 is an ATL family gene characterized by a transmembrane domain at the N‐terminal and a RING‐H2 finger domain (RFD), which exhibits ubiquitin ligase (E3) activity. To elucidate the physiological roles of EL5, we analyzed transgenic rice plants overexpressing mutant EL5 proteins that are impaired in E3 activity to various degrees. Plants expressing EL5C153A and EL5W165A, which encode an inactive E3, showed a rootless phenotype accompanied by cell death in root primordia, and those expressing EL5V162A, with moderately impaired E3 activity, formed short crown roots with necrotic lateral roots. The dominant‐negative phenotype was specifically observed in root meristems where EL5 is expressed, and not recovered by exogenous auxin. When wild‐type EL5 was transcriptionally overexpressed, the EL5 protein was barely detected by Western blotting. Neither treatment with a proteasome inhibitor nor mutation of the sole lysine residue, a potential target of ubiquitination, resulted in increased EL5 accumulation, whereas mutations in the RFD led to increased EL5 accumulation. The stabilized EL5 without the RFD was localized in the plasma membrane. Deletion of the transmembrane domain prevented the EL5 from localizing in the membrane and from exerting an inhibitory effect on root formation. Deletion of the C‐terminal region also neutralized the negative effect. We concluded that EL5 plays a major role as a membrane‐anchored E3 for the maintenance of cell viability after the initiation of root primordial formation. In addition, we propose that EL5 is an unstable protein, of which degradation is regulated by the RFD in a proteasome‐independent manner.
Identification and characterization of pin and thrum alleles of two genes that co‐segregate with the Primula S locus
Authors: Li Jinhong , Webster Margaret , Furuya Masaki , Gilmartin Philip M. 
Published: June 2007

SummaryThe study of heteromorphy in Primula over the past 140 years has established the reproductive significance of this breeding system. Plants produce either thrum or pin flowers that demonstrate reciprocal herkogamy. Thrums have short styles and produce large pollen from anthers at the mouth of the flower; pins have long styles and produce small pollen from anthers located within the corolla tube. The control of heteromorphy is orchestrated by the S locus with dominant (S) and recessive (s) alleles that comprise a co‐adapted linkage group of genes. Thrum plants are heterozygous (Ss) and pin plants are homozygous (ss). Reciprocal crosses between the two forms are required for fertilization; within‐morph crosses are impeded by a sporophytic self‐incompatibility system. Rare recombination events within the S locus produce self‐fertile homostyles. As a first step towards identifying genes located at the S locus, we used fluorescent differential display to screen for differential gene expression in pin and thrum flowers. Rather than only detecting differentially regulated genes, we identified two S locus linked genes by virtue of allelic variation between pin and thrum transcripts. Analysis of pin and thrum plants together with homostyle recombinant reveals that one gene flanks the locus, whereas the other shows complete linkage. One gene is related to Arabidopsis flower‐timing genes Col9 and Col10; the other encodes a small predicted membrane protein of unknown function. Notwithstanding the diallelic behaviour of the Primula S locus, analysis of pin and thrum plants reveal three alleles for each gene: two pin and one thrum.
A Pseudomonas syringae pv. tomato DC3000 mutant lacking the type III effector HopQ1‐1 is able to cause disease in the model plant Nicotiana benthamiana
Authors: Wei Chia‐Fong , Kvitko Brian H. , Shimizu Rena , Crabill Emerson , Alfano James R. , Lin Nai‐Chun , Martin Gregory B. , Huang Hsiou‐Chen , Collmer Alan 
Published: June 2007

SummaryThe model pathogen Pseudomonas syringae pv. tomato DC3000 causes bacterial speck in tomato and Arabidopsis, but Nicotiana benthamiana, an important model plant, is considered to be a non‐host. Strain DC3000 injects approximately 28 effector proteins into plant cells via the type III secretion system (T3SS). These proteins were individually delivered into N. benthamiana leaf cells via T3SS‐proficient Pseudomonas fluorescens, and eight, including HopQ1‐1, showed some capacity to cause cell death in this test. Four gene clusters encoding 13 effectors were deleted from DC3000: cluster II (hopH1, hopC1), IV (hopD1, hopQ1‐1, hopR1), IX (hopAA1‐2, hopV1, hopAO1, hopG1), and native plasmid pDC3000A (hopAM1‐2, hopX1, hopO1‐1, hopT1‐1). DC3000 mutants deleted for cluster IV or just hopQ1‐1 acquired the ability to grow to high levels and produce bacterial speck lesions in N. benthamiana. HopQ1‐1 showed other hallmarks of an avirulence determinant in N. benthamiana: expression in the tobacco wildfire pathogen P. syringae pv. tabaci 11528 rendered this strain avirulent in N. benthamiana, and elicitation of the hypersensitive response in N. benthamiana by HopQ1‐1 was dependent on SGT1. DC3000 polymutants involving other effector gene clusters in a hopQ1‐1‐deficient background revealed that clusters II and IX contributed to the severity of lesion symptoms in N. benthamiana, as well as in Arabidopsis and tomato. The results support the hypothesis that the host ranges of P. syringae pathovars are limited by the complex interactions of effector repertoires with plant anti‐effector surveillance systems, and they demonstrate that N. benthamiana can be a useful model host for DC3000.
Nicotinamidase activity is important for germination
Authors: Hunt Lee , Holdsworth Michael J. , Gray Julie E. 
Published: June 2007

SummaryIt has been suggested that nicotinamide must be degraded during germination; however, the enzyme responsible and its physiological role have not been previously studied. We have identified an Arabidopsis gene, NIC2, that is expressed at relatively high levels in mature seed, and encodes a nicotinamidase enzyme with homology to yeast and bacterial nicotinamidases. Seed of a knockout mutant, nic2‐1, had reduced nicotinamidase activity, retarded germination and impaired germination potential. nic2‐1 germination was restored by after‐ripening or moist chilling, but remained hypersensitive to application of nicotinamide or ABA. Nicotinamide is a known inhibitor of NAD‐degrading poly(ADP‐ribose) polymerases (PARP enzymes) that are implicated in DNA repair. We found reduced poly(ADP)ribosylation levels in nic2‐1 seed, which were restored by moist chilling. Furthermore, nic2‐1 seed had elevated levels of NAD, and germination was hypersensitive to methyl methanesulphonate (MMS), suggesting that PARP activity and DNA repair responses were impaired. We suggest that nicotinamide is normally metabolized by NIC2 during moist chilling or after‐ripening, which relieves inhibition of PARP activity and allows DNA repair to occur prior to germination.
The cell cycle‐associated protein kinase WEE1 regulates cell size in relation to endoreduplication in developing tomato fruit
Authors: Gonzalez Nathalie , Gévaudant Frédéric , Hernould Michel , Chevalier Christian , Mouras Armand 
Published: June 2007

SummaryTomato fruit size results from the combination of cell number and cell size which are respectively determined by cell division and cell expansion processes. As fruit growth is mainly sustained by cell expansion, the development of pericarp and locular tissues is characterized by the concomitant arrest of mitotic activity, inhibition of cyclin‐dependent kinase (CDK) activity, and numerous rounds of endoreduplication inducing a spectacular increase in DNA ploidy and mean cell size. To decipher the molecular basis of the endoreduplication‐associated cell growth in fruit, we investigated the putative involvement of the WEE1 kinase (Solly;WEE1). We here report a functional analysis of Solly;WEE1 in tomato. Impairing the expression of Solly;WEE1 in transgenic tomato plants resulted in a reduction of plant size and fruit size. In the most altered phenotypes, fruits displayed a reduced number of seeds without embryo development. The reduction of plant‐, fruit‐ and seed size originated from a reduction in cell size which could be correlated with a decrease of the DNA ploidy levels. At the molecular level downregulating Solly;WEE1 in planta resulted in the increase of CDKA activity levels originating from a decrease of the amount of Y15‐phosphorylated CDKA, thus indicating a release of the negative regulation on CDK activity exerted by WEE1. Our data indicated that Solly;WEE1 participates in the control of cell size and/or the onset of the endoreduplication process putatively driving cell expansion.