bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathogenicity of Botryosphaeriaceae Species Isolated from Grapevine Cankers in California
Authors: Úrbez-Torres J. R. , Gubler W. D.
Published: May 2009

Fungal species in the family Botryosphaeriaceae have been recently recognized as the most common fungi isolated from grapevine (Vitis vinifera) cankers in California. However, the role of these fungi in causing grapevine dieback as well as their status as canker-causing agents was unknown. Therefore, pathogenicity studies were conducted to determine their importance as grapevine pathogens in California. A total of 72 isolates representing all nine Botryosphaeriaceae species isolated from grapevine cankers from California were used in five different pathogenicity studies. Overall, experiments showed all nine Botryosphaeriaceae species able to infect both young and mature tissues as well as green shoots of the new vegetative growth causing cankers, vascular discoloration, and/or otherwise dark streaking of the wood. However, virulence varied among species. Lasiodiplodia theobromae was the most virulent species followed by Neofusicoccum luteum, N. parvum, and N. australe, all categorized as highly virulent. Botryosphaeria dothidea was considered intermediately virulent and Diplodia mutila, D. seriata, Dothiorella iberica, and D. viticola were shown to be weakly virulent. This study shows species of Botryosphaeriaceae to be much more important pathogens on grapevines than originally thought, and some of them, in view of their virulence, should be considered high risk for causing severe and rapid canker and dieback diseases in the grapevine industry in California.
Genetic Diversity of Prunus necrotic ringspot virus Isolates Within a Cherry Orchard in New York
Authors: Oliver J. E. , Freer J. , Andersen R. L. , Cox K. D. , Robinson T. L. , Fuchs M.
Published: May 2009

A survey for Prunus necrotic ringspot virus (PNRSV) in an orchard of Prunus cerasus cv. Montmorency and Prunus avium cv. Hedelfingen in New York by enzyme-linked immunosorbent assay indicated an eightfold higher infection rate in sour cherry (33%, 32 of 96) than in sweet cherry (4%, 6 of 136) trees. The presence of PNRSV was confirmed by reverse transcription-polymerase chain reaction and amplification of the coat protein (CP) gene in total RNA from infected leaf tissue. Latent infection was prevalent in the majority of trees infected (87%, 33 of 38), while a few of them exhibited shock symptoms or had severely reduced growth (13%, 5 of 38). Asymptomatic PNRSV-infected trees clustered in spatial proximity to symptomatic trees. Sequence analysis of the CP gene (675 bp) indicated a population structure consisting of one predominant molecular variant for 10 isolates and six minor molecular variants for seven isolates. A high sequence identity was found between the CP gene of PNRSV isolates from cherry trees and other isolates from diverse hosts and various geographic origins at the nucleotide and amino acid levels (88 to 100%). Phylogenetic analyses showed a clustering of PNRSV isolates from cherry trees in New York in the predominant group PV-96.
Bacterial Brown Leaf Spot of Citrus, a New Disease Caused by Burkholderia andropogonis
Authors: Duan Y. P. , Sun X. , Zhou L. J. , Gabriel D. W. , Benyon L. S. , Gottwald Tim
Published: May 2009

A new bacterial disease of citrus was recently identified in Florida and is here named bacterial brown leaf spot (BBLS) of citrus. BBLS-infected citrus leaves from the field displayed circular, brownish, flat lesions with slightly raised and water-soaked margins surrounded by a chlorotic halo. Based on Biolog carbon source metabolic “fingerprinting”, fatty acid analysis, and sequence analysis of partial 16S rDNA, gyrB, and rpoD genes, the causal agent of the disease was identified as Burkholderia andropogonis. Pathogenicity of these B. andropogonis isolates taken from multiple citrus leaves with BBLS was tested by various inoculation methods on three species of citrus as well as on carnation, corn, and sorghum. All isolates infected carnation, corn, and sorghum with varying degrees of pathogenicity. Variation among citrus isolates in pathogenicity was also observed in high titer (108 CFU/ml) inoculations of citrus leaves, ranging from a hypersensitive-like response to canker-like lesions. When the inoculum concentration was low (106 CFU/ml), only necrotic spots or small lesions slowly developed with all strains. Growth of B. andropogonis in citrus was relatively slow, tissue wounding appeared necessary for symptom appearance with many isolates, and field samples were recovered only after severe storms, indicating that this wide-host-range bacterium is a weak, opportunistic pathogen of citrus.
Diversity and Aggressiveness ofRhizoctonia solaniandRhizoctonia-like Fungi on Vegetables in New York
Authors: Ohkura Mana , Abawi George S. , Smart Christine D. , Hodge Kathie T.
Published: May 2009

Vegetable growers in New York, especially those growing table beets, have recently observed that the corn rotation is no longer effective in suppressing diseases caused by Rhizoctonia solani and Rhizoctonia-like fungi. To investigate this problem, 68 isolates of Rhizoctonia solani and Rhizoctonia-like fungi infecting vegetables in New York were isolated, characterized, and their pathogenicity on corn determined. Sequence analysis of the rDNA internal transcribed spacer region inferred 26 isolates to belong to R. solani anastomosis group (AG) 2-2 and 19 isolates to belong to AG 4. Remaining isolates belonged to AG 1, AG 2-1, AG 5, AG 11, Ceratobasidium AG (CAG) 2, CAG 6, and Waitea circinata var. zeae. This is a first report of AG 11 and W. circinata var. zeae recovered from naturally infected vegetables in New York. Pathogenicity tests on corn showed that the majority of isolates are pathogenic on corn, and isolates belonging to AG 2-2, AG 5, and AG 11 exhibited high aggressiveness. These results suggest that certain strains of R. solani and Rhizoctonia-like fungi infecting vegetables in New York have acquired the ability to infect corn. In addition, snap bean was inoculated with seven isolates exhibiting low to high aggressiveness on corn, and a correlation between aggressiveness on corn and snap bean was observed.
Effect of Production System and Pruning on Temporal Development of Cercospora depazeoides and on Berry Yield in Black Elderberry Orchards
Authors: Holb I. J. , Gáll J. M. , Fodor B.
Published: May 2009

In a 2-year study, the temporal development of Cercospora leaf spot (Cercospora depazeoides) and berry yield were evaluated in two production systems (integrated and organic) and in two winter pruning treatments (trees pruned to four and eight scaffolds) in two black elderberry (Sambucus nigra) orchards in Hungary. Under organic production, leaf spot onset occurred 2 to 4 weeks earlier (mid- and late July) in both years and both orchards compared with the integrated program. Disease then continuously progressed until the final assessment date (late September) in both years, reaching a maximum final disease incidence of 15.9% in the integrated system and of 38.2% in the organic system. In general, disease progress after late August was greater on trees pruned to eight scaffolds than on trees pruned to four scaffolds in both production systems. Both final disease incidence and area under the disease progress curves (AUDPC) were significantly lower (P < 0.001) in the integrated treatments compared with organic ones. Across all treatments, both disease measures were significantly (P < 0.05) lower on trees pruned to four scaffolds compared with trees pruned to eight scaffolds. However, when the effect of pruning on final disease incidence and AUDPC was analyzed separately for integrated and organic systems, pruning caused uniformly significant differences in disease development only for the organic system. Berry yield was significantly higher (P < 0.05) in the integrated system compared with the organic system, but pruning showed no significant effect on yield. Overall, pruning to four scaffolds resulted in consistently lower disease development in organic production compared to integrated. Thus, winter pruning may be useful as a Cercospora leaf spot management practice in organic elderberry orchards.
Quantitative Resistance to Bean dwarf mosaic virus in Common Bean Is Associated with the Bct Gene for Resistance to Beet curly top virus
Authors: Miklas P. N. , Seo Y.-S. , Gilbertson R. L.
Published: May 2009

The dominant resistance gene, Bct, in common bean (Phaseolus vulgaris) confers qualitative resistance to Beet curly top virus, a leafhopper-transmitted geminivirus in the genus Curtovirus. To determine whether this gene confers resistance to other geminiviruses, bean plants of a recombinant inbred population were sap-inoculated with Bean dwarf mosaic virus (BDMV), a whitefly-transmitted bipartite begomovirus in the genus Begomovirus. Results indicated that Bct (or tightly linked gene) is associated with quantitative resistance to BDMV; thus, the Bct locus is associated with resistance to a bean-infecting begomovirus and curtovirus. The difference in the nature of the resistance to these geminiviruses may indicate a role for minor genes in begomovirus resistance or differences in the virus–host interaction. The Bct locus, whether it acts alone or represents a cluster of tightly linked genes, will be useful in breeding for broad-spectrum begomovirus resistance in common bean.
Brown Blotch Caused by Pseudomonas tolaasii on Cultivated Pleurotus eryngii in Spain
Authors: González A. J. , González-Varela G. , Gea F. J.
Published: May 2009

In 2006, symptoms of brown blotch were observed on cultivated Pleurotus eryngii (king oyster mushroom) in Castilla-La Mancha (Spain). Subsequently, between January and May of 2008, brown blotch affected 39.75% of the blocks of substrate cultivated, resulting in a considerable loss of production. Symptoms observed were principally characterized by a yellowish brown-to-orangish color, first of the cap and then of the stalk. Some samples also showed a slightly concave cap. From samples collected from four different king oyster mushroom farms, a fluorescent gram-negative bacterium was recovered on King's B medium and identified as Pseudomonas tolaasii by the LOPAT scheme and other tests (2). The bacterium isolated had the following characteristics: oxidative, positive for oxidase and arginine dihydrolase, negative for levan production, pectinolitic activity on potato slices, and tobacco hypersensitivity. Results from other tests were as follows: negative for esculin hydrolysis and positive for gelatine, casein, and Tween 80 hydrolysis; mannitol, erythritol, sorbitol, m-inositol, and adonitol were used as a sole carbon source, but not sucrose, d-tartrate, or trigonelline. The white line test was performed (4) using P. reactans LPPA 540 and the presumptive isolates of P. tolaasii were positive. The gene encoding the 16S rRNA from two isolates (LPPA532 and LPPA533) was sequenced after PCR amplification (2) and their nucleotide sequences (1,400 bp; EMBL Accession No. FM864215 for LPPA 532) proved to be identical. The amplified sequences were compared with DNA sequences available in databases (GenBank, EMBL, DDBJ, and PDB) by using BLAST. An identity of 99% was obtained with 16S rDNA of three P. tolaasii strains (GenBank Accession Nos. AF320990, AF094750, and AF255336). Four isolates were selected for pathogenicity tests. Bacterial suspensions were grown for 16 h in yeast peptone glucose broth (approximately 108 CFU/ml) and were inoculated by puncture into 10 mushroom caps using sterilized wooden toothpicks (4). Sterilized distilled water was used as a control. These were then incubated at room temperature in glass dishes. Assays were conducted twice and the results were recorded after 10 days. The symptoms that developed after infection were similar to those observed in the crop, while the control mushrooms remained symptomless. Bacteria sharing the characteristics of the inoculated isolates were recovered from symptomatic caps. P. tolaasii has been described as causing brown blotch on Pleurotus eryngii (1,3), but to our knowledge, this is the first report of P. tolaasii causing brown blotch on Pleurotus eryngii in Spain.

References: (1) J. F. Bradbury. No. 891 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1987. (2) A. J. González et al. Appl. Environ. Microbiol. 69:2936, 2003. (3) A. Russo et al. Microbiol. Res. 158:265, 2003. (4) J. M. Wells et al. Phytopathology 86:1098, 1996.
Spinach (Spinacia oleracea) is a New Natural Host of Impatiens necrotic spot virus in California
Authors: Liu H.-Y. , Sears J. L. , Mou B.
Published: May 2009

Spinach (Spinacia oleracea) plants exhibiting severe stunting and leaves that showed interveinal yellowing, thickening, and deformation were found in an experimental trial adjacent to an artichoke field in Monterey County, CA in October of 2008. Percent incidence of symptomatic plants ranged from 20 to 39% in cvs. Bordeaux, Lazio, and Tigercat. Symptomatic plants were positive for Impatiens necrotic spot virus (INSV; family Bunyaviridae, genus Tospovirus) and were negative for Tomato spotted wilt virus, Cucumber mosaic virus, and Tobacco mosaic virus when tested with immunostrips (Agdia Inc., Elkhart, IN). The INSV-positive spinach was used for mechanical transmission to Nicotiana benthamiana, Chenopodium quinoa, and spinach. All inoculated plants were positive for INSV with immunostrips. To further confirm the presence of INSV, reverse transcription (RT)-PCR was conducted. Total RNA was extracted from the symptomatic spinach plants using a RNeasy Plant Kit (Qiagen Inc., Valencia, CA) and used as a template in RT-PCR using forward (5′-GGATGTAAGCCCTTCTTTGTAGTGG-3′) and reverse (5′-CCTTCCAAGTCACCCTCTGATTG-3′) primers specific to the INSV nucleoprotein (N) gene (GenBank Accession No. DQ425096). Amplicons of the expected size (approximately 364 bp) were obtained from both field-infected and mechanically inoculated spinach plants. Four amplicons were sequenced and compared with INSV N gene sequence in GenBank to confirm the identity of the products. Sequences obtained had 99% nucleotide identity with INSV sequences available under the GenBank Accession Nos. L20885, DQ523597, DQ523598, X66872, L20886, D00914, AB109100, and DQ425096. INSV can be one of the most serious viral pathogens of ornamental plants in North America and Europe. The host range of INSV is expanding and recent reports of INSV infection of vegetables include lettuce, peppers, peanut, and potato (1–4). To our knowledge, this is the first report of natural occurrence of INSV in spinach in California. Since INSV is vectored by thrips, its expanding natural host could make it an economically important problem in California and the United States.

References: (1) S. T. Koike et al. Plant Dis. 92:1248, 2008. (2) R. A. Naidu et al. Online publication. doi:10.1094/PHP-2005-0727-01-HN, Plant Health Progress, 2005. (3) S. S Pappu et al. Plant Dis. 83:966, 1999. (4) K. L. Perry et al. Plant Dis. 89:340, 2005.
The cellular geometry of growth drives the amino acid economy ofCaenorhabditis elegans
Authors: Swire Jonathan , Fuchs Silke , Bundy Jacob G. , Leroi Armand M.
Published: May 2009

The nematodeCaenorhabditis elegansgrows largely by increases in cell size. As a consequence of this, the surface: volume ratio of its cells must decline in the course of postembryonic growth. Here we use transcriptomic and metabolomic data to show that this change in geometry can explain a variety of phenomena during growth, including: (i) changes in the relative expression levels of cytoplasmic and membrane proteins; (ii) changes in the relative usage of the twenty amino acids in expressed proteins, as estimated by changes in the transcriptome; and (iii) changes in metabolite pools of free amino acids. We expect these relations to be universal in single cells and in whole multicellular organisms that grow largely by increases in cell size, but not those that grow by cell proliferation.
Old fossils–young species: evolutionary history of an endemic gastropod assemblage in Lake Malawi
Authors: Schultheiß Roland , Van Bocxlaer Bert , Wilke Thomas , Albrecht Christian
Published: May 2009

Studies on environmental changes provide important insights into modes of speciation, into the (adaptive) reoccupation of ecological niches and into species turnover. Against this background, we here examine the history of the gastropod genusLanistesin the African Rift Lake Malawi, guided by four general evolutionary scenarios, and compare it with patterns reported from other endemic Malawian rift taxa. Based on an integrated approach using a mitochondrial DNA phylogeny and a trait-specific molecular clock in combination with insights from the fossil record and palaeoenvironmental data, we demonstrate that the accumulation of extant molecular diversity in the endemic group did not start before approximately 600 000 years ago from a single lineage. Fossils of the genus from the Malawi Rift, however, are over one million years older. We argue that severe drops in the lake level of Lake Malawi in the Pleistocene offer a potential explanation for this pattern. Our results also challenge previously established phylogenetic relationships within the genus by revealing parallel evolution and providing evidence that the endemicLanistesspecies are not restricted to the lake proper but are present throughout the Malawi Rift.
A chemical signal of offspring quality affects maternal care in a social insect
Authors: Mas Flore , Haynes Kenneth F. , Kölliker Mathias
Published: May 2009

Begging signals of offspring are condition-dependent cues that are usually predicted to display information about the short-term need (i.e. hunger) to which parents respond by allocating more food. However, recent models and experiments have revealed that parents, depending on the species and context, may respond to signals of quality (i.e. offspring reproductive value) rather than need. Despite the critical importance of this distinction for life history and conflict resolution theory, there is still limited knowledge of alternative functions of offspring signals. In this study, we investigated the communication between offspring and caring females of the common earwig,
Forficula auricularia
, hypothesizing that offspring chemical cues display information about nutritional condition to which females respond in terms of maternal food provisioning. Consistent with the prediction for a signal of quality we found that mothers exposed to chemical cues from well-fed nymphs foraged significantly more and allocated food to more nymphs compared with females exposed to solvent (control) or chemical cues from poorly fed nymphs. Chemical analysis revealed significant differences in the relative quantities of specific cuticular hydrocarbon compounds between treatments. To our knowledge, this study demonstrates for the first time that an offspring chemical signal reflects nutritional quality and influences maternal care.
Are rates of species diversification correlated with rates of morphological evolution?
Authors: Adams Dean C. , Berns Chelsea M. , Kozak Kenneth H. , Wiens John J.
Published: May 2009

Some major evolutionary theories predict a relationship between rates of proliferation of new species (species diversification) and rates of morphological divergence between them. However, this relationship has not been rigorously tested using phylogeny-based approaches. Here, we test this relationship with morphological and phylogenetic data from 190 species of plethodontid salamanders. Surprisingly, we find that rates of species diversification and morphological evolution are not significantly correlated, such that rapid diversification can occur with little morphological change, andvice versa. We also find that most clades have undergone remarkably similar patterns of morphological evolution (despite extensive sympatry) and that those relatively novel phenotypes are not associated with rapid diversification. Finally, we find a strong relationship between rates of size and shape evolution, which has not been previously tested.
Epibionts on the lingulate brachiopod
Diandongia
from the Early Cambrian Chengjiang Lagerstätte, South China
Authors: Zhang Zhifei , Han Jian , Wang Yang , Emig Christian C. , Shu Degan
Published: May 2009

The classic Chengjiang Lagerstätte (Lower Cambrian, Atdabanian stage: Yu'anshan Formation) Yunnan, southwestern China, has yielded, besides the exceptional and often controversial soft-bodied fossils, a fauna of primitive/early lingulid brachiopods.
Diandongia pista
(Rong 1974) is one of the commonest and most strongly mineralized of the phosphatic brachiopods from the Lagerstätte. The shells of this species have been found to commonly serve as a basibiont host. Epibionts comprise the coeval brachiopod
Longtancunella chengjiangensis
and the cone-shaped cnidarian-related
Archotuba conoidalis
, as well as rounded smaller-sized epizoans (lesser than 2 mm). A principle morphological analysis demonstrates that the ovoid and rounded organisms that often occur along the commissure of
D. pista
resemble small juvenile or immature brachiopods. Epibiont-bearing shells of
D. pista
with soft-tissue preservation demonstrate that the host brachiopods were overgrown while alive, and provide an argument for
D. pista
having a semi-infaunal life style with only the slim pedicle embedded in sediment. The epibiotic association sheds direct light on the ecology of Cambrian brachiopods in soft-substrate marine environments. The Chengjiang fossils demonstrate that the Early Cambrian brachiopods, as compared with recent lingulids, occupied different and a wider spectrum of ecological niches and tiers of space.
The earliest history of the deuterostomes: the importance of the Chengjiang Fossil-Lagerstätte
Authors: Shu D.-G. , Conway Morris S. , Zhang Z.-F. , Han J.
Published: May 2009

While the broad framework of deuterostome evolution is now clear, the remarkable diversity of extant forms within this group has rendered the nature of the ancestral types problematic: what, for example, does the common ancestor of a sea urchin and lamprey actually look like? The answer to such questions can be addressed on the basis of remarkably well-preserved fossils from Cambrian Lagerstätten, not least the celebrated Chengjiang Lagerstätte (Yunnan, China). This deposit is particularly important because of its rich diversity of deuterostomes. These include some of the earliest known representatives, among which are the first vertebrates, as well as more enigmatic groups, notably the vetulicolians and yunnanozoans. The latter groups, in particular, have been the subject of some radical divergences in opinion as to their exact phylogenetic placements. Here, we both review the known diversity of Chengjiang deuterostomes and in particular argue that the vetulicolians and yunnanozoans represent very primitive deuterostomes. Moreover, in the latter case we present new data to indicate that the yunnanozoans are unlikely to be any sort of chordate.
Does the human X contain a third evolutionary block? Origin of genes on human Xp11 and Xq28
Authors: Delbridge Margaret L. , Patel Hardip R. , Waters Paul D. , McMillan Daniel A. , Marshall Graves Jennifer A.
Published: May 2009

Comparative gene mapping of human X-borne genes in marsupials defined an ancient conserved region and a recently added region of the eutherian X, and the separate evolutionary origins of these regions was confirmed by their locations on chicken chromosomes 4p and 1q, respectively. However, two groups of genes, from the pericentric region of the short arm of the human X (at Xp11) and a large group of genes from human Xq28, were thought to be part of a third evolutionary block, being located in a single region in fish, but mapping to chicken chromosomes other than 4p and 1q. We tested this hypothesis by comparative mapping of genes in these regions. Our gene mapping results show that human Xp11 genes are located on the marsupial X chromosome and platypus chromosome 6, indicating that the Xp11 region was part of original therian X chromosome. We investigated the evolutionary origin of genes from human Xp11 and Xq28, finding that chicken paralogs of human Xp11 and Xq28 genes had been misidentified as orthologs, and their true orthologs are represented in the chicken EST database, but not in the current chicken genome assembly. This completely undermines the evidence supporting a separate evolutionary origin for this region of the human X chromosome, and we conclude, instead, that it was part of the ancient autosome, which became the conserved region of the therian X chromosome 166 million years ago.
Efficient frequency-based de novo short-read clustering for error trimming in next-generation sequencing
Authors: Qu Wei , Hashimoto Shin-ichi , Morishita Shinichi
Published: May 2009

Novel massively parallel sequencing technologies provide highly detailed structures of transcriptomes and genomes by yielding deep coverage of short reads, but their utility is limited by inadequate sequencing quality and short-read lengths. Sequencing-error trimming in short reads is therefore a vital process that could improve the rate of successful reference mapping and polymorphism detection. Toward this aim, we herein report a frequency-based, de novo short-read clustering method that organizes erroneous short sequences originating in a single abundant sequence into a tree structure; in this structure, each “child” sequence is considered to be stochastically derived from its more abundant “parent” sequence with one mutation through sequencing errors. The root node is the most frequently observed sequence that represents all erroneous reads in the entire tree, allowing the alignment of the reliable representative read to the genome without the risk of mapping erroneous reads to false-positive positions. This method complements base calling and the error correction of making direct alignments with the reference genome, and is able to improve the overall accuracy of short-read alignment by consulting the inherent relationships among the entire set of reads. The algorithm runs efficiently with a linear time complexity. In addition, an error rate evaluation model can be derived from bacterial artificial chromosome sequencing data obtained in the same run as a control. In two clustering experiments using small RNA and 5′-end mRNA reads data sets, we confirmed a remarkable increase (∼5%) in the percentage of short reads aligned to the reference sequence.
Functional Characterization of the Arabidopsisβ-Ketoacyl-Coenzyme A Reductase Candidates of the Fatty Acid Elongase
Authors: Beaudoin Frédéric , Wu Xianzhong , Li Fengling , Haslam Richard P. , Markham Jennifer E. , Zheng Huanquan , Napier Johnathan A. , Kunst Ljerka
Published: May 2009

In plants, very-long-chain fatty acids (VLCFAs; >18 carbon) are precursors of sphingolipids, triacylglycerols, cuticular waxes, and suberin. VLCFAs are synthesized by a multiprotein membrane-bound fatty acid elongation system that catalyzes four successive enzymatic reactions: condensation, reduction, dehydration, and a second reduction. A bioinformatics survey of the Arabidopsis (Arabidopsis thaliana) genome has revealed two sequences homologous to YBR159w encoding a Saccharomyces cerevisiae β-ketoacyl reductase (KCR), which catalyzes the first reduction during VLCFA elongation. Expression analyses showed that both AtKCR1 and AtKCR2 genes were transcribed in siliques, flowers, inflorescence stems, leaves, as well as developing embryos, but only AtKCR1 transcript was detected in roots. Fluorescent protein-tagged AtKCR1 and AtKCR2 were localized to the endoplasmic reticulum, the site of fatty acid elongation. Complementation of the yeast ybr159Δ mutant demonstrated that the two KCR proteins are divergent and that only AtKCR1 can restore heterologous elongase activity similar to the native yeast KCR gene. Analyses of insertional mutants in AtKCR1 and AtKCR2 revealed that loss of AtKCR1 function results in embryo lethality, which cannot be rescued by AtKCR2 expression using the AtKCR1 promoter. In contrast, a disruption of the AtKCR2 gene had no obvious phenotypic effect. Taken together, these results indicate that only AtKCR1 is a functional KCR isoform involved in microsomal fatty acid elongation. To investigate the roles of AtKCR1 in postembryonic development, transgenic lines expressing RNA interference and overexpression constructs targeted against AtKCR1 were generated. Morphological and biochemical characterization of these lines confirmed that suppressed KCR activity results in a reduction of cuticular wax load and affects VLCFA composition of sphingolipids, seed triacylglycerols, and root glycerolipids, demonstrating in planta that KCR is involved in elongation reactions supplying VLCFA for all these diverse classes of lipids.
Senescence-Induced Serotonin Biosynthesis and Its Role in Delaying Senescence in Rice Leaves
Authors: Kang Kiyoon , Kim Young-Soon , Park Sangkyu , Back Kyoungwhan
Published: May 2009

Serotonin, which is well known as a pineal hormone in mammals, plays a key role in conditions such as mood, eating disorders, and alcoholism. In plants, although serotonin has been suggested to be involved in several physiological roles, including flowering, morphogenesis, and adaptation to environmental changes, its regulation and functional roles are as yet not characterized at the molecular level. In this study, we found that serotonin is greatly accumulated in rice (Oryza sativa) leaves undergoing senescence induced by either nutrient deprivation or detachment, and its synthesis is closely coupled with transcriptional and enzymatic induction of the tryptophan biosynthetic genes as well as tryptophan decarboxylase (TDC). Transgenic rice plants that overexpressed TDC accumulated higher levels of serotonin than the wild type and showed delayed senescence of rice leaves. However, transgenic rice plants, in which expression of TDC was suppressed through an RNA interference (RNAi) system, produced less serotonin and senesced faster than the wild type, suggesting that serotonin is involved in attenuating leaf senescence. The senescence-retarding activity of serotonin is associated with its high antioxidant activity compared to either tryptophan or chlorogenic acid. Results of TDC overexpression and TDC RNAi plants suggest that TDC plays a rate-limiting role for serotonin accumulation, but the synthesis of serotonin depends on an absolute amount of tryptophan accumulation by the coordinate induction of the tryptophan biosynthetic genes. In addition, immunolocalization analysis revealed that serotonin was abundant in the vascular parenchyma cells, including companion cells and xylem-parenchyma cells, suggestive of its involvement in maintaining the cellular integrity of these cells for facilitating efficient nutrient recycling from senescing leaves to sink tissues during senescence.
Acyl‐CoA synthetase as a cancer survival factor: its inhibition enhances the efficacy of etoposide
Authors: Mashima Tetsuo , Sato Shigeo , Okabe Sachiko , Miyata Satoshi , Matsuura Masaaki , Sugimoto Yoshikazu , Tsuruo Takashi , Seimiya Hiroyuki
Published: May 2009

Lipid metabolism is often elevated in cancer cells and plays an important role in their growth and malignancy. Acyl‐CoA synthetase (ACS), which converts long‐chain fatty acids to acyl‐CoA, is overexpressed in various types of cancer. However, the role of ACS in cancer remains unknown. Here, we found that ACS enzyme activity is required for cancer cell survival. Namely, the ACS inhibitor Triacsin c induced massive apoptosis in glioma cells while this cell death was completely suppressed by overexpression of ACSL5, the Triacsin c–resistant ACS isozyme, but not by overexpression of a catalytically inactive ACSL5 mutant. ACS inhibition by Triacsin c markedly potentiated the Bax‐induced intrinsic apoptotic pathway by promoting cytochrome c release and subsequent caspase activation. These effects were abrogated by ACSL5 overexpression. Correspondingly, ACS inhibition synergistically potentiated the glioma cell death induced by etoposide, a well‐known activator of apoptosis. Furthermore, in a nude mouse xenograft model, Triacsin c at a non‐toxic dose enhanced the antitumor efficacy of a low‐dose chemotherapy with etoposide. These results indicate that ACS is an apoptosis suppressor and that ACS inhibition could be a rational strategy to amplify the antitumor effect of etoposide. (Cancer Sci 2009)
Characterizing soil surface roughness using a combined structural and spectral approach
Authors: Croft H. , Anderson K. , Kuhn N. J.
Published: May 2009

The ability to quantitatively and spatially assess soil surface roughness is important in geomorphology and land degradation studies. This paper describes the results of an experiment designed to investigate whether hyperspectral directional reflectance factors can describe fine‐scale variations in soil surface roughness. A Canadian silt loam soil was sieved to an aggregate size range of 1–4.75 mm and exposed to five different artificial rainfall durations to produce soils displaying progressively decreasing levels of surface roughness. Each soil state was measured using a point laser profiling instrument at 2 mm spatial resolution, in order to provide information on the structure and spatial arrangement of soil particles. Hyperspectral directional reflectance factors were measured using an Analytical Spectral Devices FieldSpec Pro Spectroradiometer (range 350–2500 nm), at a range of measurement angles (θr=−60° to +60°) and illumination angle conditions (θi= 28°–74°). Directional reflectance factors varied with illumination and view angles, and with soil structure. Geostatistically‐derived indicators of soil surface roughness (sill variance) were regressed with directional reflectance factors. The results showed a strong relationship between directional reflectance and surface roughness (R2= 0.94 where θr=−60°, θi= 67°–74°). This fine‐scale quasi‐natural experiment allowed the control of slope, initial aggregate size and rainfall exposure, permitting an investigation into factors affecting a soil’s bidirectional reflectance response. This has highlighted the relationship between fine‐scale variations in surface roughness, illumination angle and reflectance response. The results show how the technique could provide a quantitative measure of surface roughness at fine spatial scales.
SEM image analysis in the study of a soil chronosequence on fluvial terraces of the middle Guadalquivir (southern Spain)
Authors: Calero J. , Delgado R. , Delgado G. , Martín‐García J. M.
Published: May 2009

A Quaternary fluvial chronosequence (Guadalquivir River, southern Spain), consisting of five soil profiles with estimated ages of 300 years (Haplic Fluvisol), 7000 years (Haplic Calcisol), 70 000 years (Cutanic Luvisol), 300 000 years (Lixic Calcisol) and 600 000 years (Cutanic Luvisol), was studied. Increasing soil age was associated with increases in: reddening, development of structure, clay content, dithionite‐extractable iron (Fed) and aluminium (Ald) and strengthening of X‐ray diffraction (XRD) peaks for phyllosilicates and iron oxides; there were also decreases in pH and percentage of carbonates in the fine earth and lower XRD peaks for calcite and dolomite. These changes indicate that the principal pedogenic processes were weathering, clay illuviation, rubefaction and the weathering and leaching of carbonates. We have further characterized the pedogenetic chronosequence by quantification of ultramicrofabrics of ped interiors using image analysis (IA) techniques on images obtained with scanning electron microscopy (SEM). We have estimated morphometric ultramicrofabric parameters for particle clusters, skeleton grains and pore space. These are closely related to analytical, mineralogical and macromorphological properties. In the principal component analysis, the first two principal components of the combined morphological, analytical and mineralogical data accounted for 78% of the total variance. The first component (48%) is loaded by variables associated with clay illuviation, relative accumulation of iron and aluminium sesquioxides and the weathering and leaching of carbonates. The components are related to ultramicrofabric development trends. We tested several chronofunctions derived from analytical and morphometric attributes. The logarithmic model fitted best, and we interpret this as indicating pedogenetic processes that are converging towards a steady state.
Effect of redox conditions on phosphate exchangeability and iron forms in a soil amended with ferrous iron
Authors: Schärer M. , De Grave E. , Semalulu O. , Sinaj S. , Vandenberghe R. E. , Frossard E.
Published: May 2009

Application of iron (Fe) ‐rich amendments to soils has been proposed as a means of decreasing phosphorus (P) losses from soils. However, anoxic conditions following soil saturation are known to increase Fe and P solubility in soils, thus cancelling out the potential benefits. Our aim was to evaluate the effects of continuous oxic, continuous anoxic and alternating anoxic/oxic conditions on P exchangeability and Fe forms in soil amended with Ca(OH)2 and FeSO4. We incubated amended and unamended soils under these conditions for 8 weeks and measured Fe forms and P exchangeability. Under oxic conditions, addition of Ca(OH)2 and FeSO4 resulted in a strong decrease in P exchangeability and an increase in oxalate‐extractable Fe. Mössbauer analyses suggested that an unidentified Fe oxide (D1oxide) with a strong sorbing capacity for P was precipitated. Under continuously anoxic conditions, P exchangeability and oxalate‐extractable Fe increased with or without the amendments. Mössbauer analyses suggested that there was a partial dissolution of the D1oxide phase, precipitation of another unidentified Fe oxide (S3) and a reduction of structural Fe3+ in phyllosilicate, thereby increasing soil negative charge. These transformations resulted in a strong increase in rapidly exchangeable P. Alternating anoxic and oxic periods induced the dissolution and precipitation of iron oxides and the increase and decrease in P exchangeability. Implications of the results for limiting P losses from grassland soils are discussed.
British Society of Paediatric Dentistry: a policy document on dental neglect in children
Authors: Harris Jenny C. , Balmer Richard C. , Sidebotham Peter D.
Published: May 2009

This policy document was prepared by J.C. Harris, R.C. Balmer, and P.D. Sidebotham on behalf of the British Society of Paediatric Dentistry (BSPD). Policy documents produced by the BSPD represent a majority view, based on consideration of currently available evidence. They are produced to provide guidance with the clear intention that the policy be regularly reviewed and updated to take account of changing views and developments.
Reflection paper on the use of third and fourth generation cephalosporins in food producing animals in the European Union: development of resistance and impact on human and animal health
Authors: Scientific Advisory Group on Antimicrobials of the Committee
Published: May 2009

Resistance to third and fourth generation cephalosporins is rapidly increasing in bacteria infecting humans. Although many of these problems are linked to human to human transmission and to use of antimicrobials in human medicine, the potential role of community reservoirs such as food producing animals needs to be scrutinized. Resistance to third and fourth generation cephalosporins is emerging in enteric bacteria of food producing animals and also in food of animal origin. The genes encoding resistance to these cephalosporins are transferrable and often linked to other resistance genes. Systemic use of third and fourth cephalosporins selects for resistance, but co‐selection by other antimicrobials is also likely to influence prevalence of resistance. Although there are many uncertainties, the potential consequences of a further increase of resistance to this critically important class of antimicrobials in bacteria colonising animals are serious. Measures to counter a further increase and spread of resistance among animals should therefore be considered.
Investigating socio‐economic disparities in preterm birth: evidence for selective study participation and selection bias
Authors: Kramer Michael S. , Wilkins Russell , Goulet Lise , Séguin Louise , Lydon John , Kahn Susan R. , McNamara Helen , Dassa Clément , Dahhou Mourad , Masse André , Miner Louise , Asselin Guylaine , Gauthier Henriette , Ghanem Antoinette , Benjamin Alice , Platt Robert W. ,   Montreal Prematurity Study Group
Published: May 2009

Selective study participation can theoretically lead to selection bias. We explored this issue in the context of a multicentre cohort study of socio‐economic disparities in preterm birth. Women with singleton pregnancies were recruited from four large Montreal maternity hospitals and invited to return for an interview, vaginal examination and venepuncture at 24–26 weeks of gestation. We compared the observed preterm birth rate (ultrasound confirmed) among the 5146 cohort women to that expected based on all 108 724 Montreal Census Metropolitan Area (CMA) singleton births for 1998–2000.

The observed preterm birth rate in the study cohort was 5.1%, compared with 6.3% in the CMA (P < 0.001) (unadjusted morbidity ratio [95% CI] = 0.80 [0.71, 0.90]). Within each stratum of maternal education and neighbourhood income (the latter based on postal code matched links to the 2001 Canadian census), cohort women had substantially lower rates of preterm birth than women from the CMA. No significant association between socio‐economic status (SES) and preterm birth was observed in the study cohort, except among ‘indicated’ (non‐spontaneous) cases. The association between neighbourhood income and preterm birth was biased to the null in the study cohort, with adjusted odds ratios in the poorest vs. richest quintiles of 1.01 [0.63, 1.64] in the cohort vs. 1.28 [1.18, 1.39] in the CMA, although no such bias was observed for the association with maternal education assessed at the individual level. We speculate that the lower‐than‐expected preterm birth rate and attenuated association between neighbourhood income and preterm birth may be related to selective participation by women more psychologically invested in their pregnancies. Investigators should consider the potential for biased associations in pregnancy/birth cohort studies, especially associations based on SES or race/ethnicity, and carry out sensitivity analyses to gauge their effects.
Do differences in maternal age, parity and multiple births explain variations in fetal and neonatal mortality rates in Europe? – Results from the EURO‐PERISTAT project
Authors: Anthony Sabine , Jacobusse Gert W. , Van Der Pal‐de Bruin Karin M. , Buitendijk Simone , Zeitlin Jennifer ,   EURO‐PERISTAT Working Group on Risk Factors
Published: May 2009

Perinatal mortality rates differ markedly between countries in Europe. If population characteristics, such as maternal age, parity or multiple births, contribute to these differences, standardised rates may be useful for international comparisons of health status and especially quality of care. This analysis used aggregated population‐based data on fetal and neonatal mortality stratified by maternal age, parity and multiple birth from 12 countries participating in the EURO‐PERISTAT project to explore this question. Adjusted odds ratios were computed for fetal and neonatal mortality and tested for inter‐country heterogeneity; standardised mortality rates were calculated using a direct standardisation method.

There were wide variations in fetal and neonatal mortality rates, from 3.3 to 7.1 and 2.0 to 6.0 per 1000 total and livebirths, respectively, and in the prevalence of mothers over 35 (7–22%), primiparae (41–50%) and multiple births (2–4%). These population characteristics had a significant association with mortality, although results were less consistent for primiparity. Odds ratios for older mothers and primiparae showed significant inter‐country heterogeneity. The association between maternal age and fetal mortality declined as the prevalence of older mothers in the population increased. Standardised rates did not substantially change inter‐country rankings and demographic characteristics did not explain the higher mortality observed in some countries. Our results do not support the use of mortality rates standardised for age, parity and multiple births for international comparisons of quality of care. Further research should explore why the negative effects of older maternal age decrease as delayed childbearing becomes more common and, in particular, whether this is due to changes in the social characteristics of older mothers or in health care provision.
Maternal residential proximity to waste sites and industrial facilities and conotruncal heart defects in offspring
Authors: Langlois Peter H. , Brender Jean D. , Suarez Lucina , Zhan F. Benjamin , Mistry Jatin H. , Scheuerle Angela , Moody Karen
Published: May 2009

Most studies of the relationship between maternal residential proximity to sources of environmental pollution and congenital cardiovascular malformations have combined heart defects into one group or broad subgroups. The current case–control study examined whether risk of conotruncal heart defects, including subsets of specific defects, was associated with maternal residential proximity to hazardous waste sites and industrial facilities with recorded air emissions. Texas Birth Defects Registry cases were linked to their birth or fetal death certificate. Controls without birth defects were randomly selected from birth certificates. Distances from maternal addresses at delivery to National Priority List (NPL) waste sites, state superfund waste sites, and Toxic Release Inventory (TRI) facilities were determined for 1244 cases (89.5% of those eligible) and 4368 controls (88.0%).

Living within 1 mile of a hazardous waste site was not associated with risk of conotruncal heart defects [adjusted odds ratio (aOR) = 0.83, 95% confidence interval (CI) = 0.54, 1.27]. This was true whether looking at most types of defects or waste sites. Only truncus arteriosus showed statistically elevated ORs with any waste site (crude OR: 2.80, 95% CI 1.19, 6.54) and with NPL sites (crude OR: 4.63, 95% CI 1.18, 13.15; aOR 4.99, 95% CI 1.26, 14.51), but the latter was based on only four exposed cases. There was minimal association between conotruncal heart defects and proximity to TRI facilities (aOR = 1.10, 95% CI = 0.91, 1.33). Stratification by maternal age or race/ethnic group made little difference in effect estimates for waste sites or industrial facilities. In this study population, maternal residential proximity to waste sites or industries with reported air emissions was not associated with conotruncal heart defects or its subtypes in offspring, with the exception of truncus arteriosus.