bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deciphering regulatory mechanisms for secondary metabolite production in the myxobacterium Sorangium cellulosum So ce56
Authors: Rachid Shwan , Gerth Klaus , Kochems Irene , Müller Rolf 
Published: March 2007

Summary Sorangium cellulosum strains produce approximately 50% of the biologically active secondary metabolites known from myxobacteria. These metabolites include several compounds of biotechnological importance such as the epothilones and chivosazols, which, respectively, stabilize the tubulin and actin skeletons of eukaryotic cells. S. cellulosum is characterized by its slow growth rate, and natural products are typically produced in low yield. In this study, biomagnetic bead separation of promoter‐binding proteins and subsequent inactivation experiments were employed to identify the chivosazol regulator, ChiR, as a positive regulator of chivosazol biosynthesis in the genome‐sequenced strain So ce56. Overexpression of chiR under the control of T7A1 promoter in a merodiploid mutant resulted in fivefold overproduction of chivosazol in a kinetic shake flask experiment, and 2.5‐fold overproduction by fermentation. Using quantitative reverse transcription PCR and gel shift experiments employing heterologously expressed ChiR, we have shown that transcription of the chivosazol biosynthetic genes (chiA–chiF) is directly controlled by this protein. In addition, we have demonstrated that ChiR serves as a pleiotropic regulator in S. cellulosum, because mutant strains lack the ability to develop into regular fruiting bodies.
A tale of two dead ends: origin of a potential new gene and a potential new transposable element
Authors: Clutterbuck A. John 
Published: March 2007

SummaryAn article in this issue of Molecular Microbiology by Cultrone et al. describes how a non‐autonomous helitron element could arise from its autonomous parent transposon by deletion followed by readthrough into an adjacent gene and its promoter, thus providing a mechanism for distribution of a specifically regulated promoter sequence around the genome, where it would have the potential to evolve new functions.
Genetic structure and spatial distribution of the mycoparasite Sphaerellopsis filum on Melampsora larici‐epitea in a short‐rotation coppice willow planting
Authors: Bayon C. , Pei M. H. , Ruiz C. , Hunter T. 
Published: March 2007

AFLP analysis was used to examine the genetic structure of the mycoparasite Sphaerellopsis filum on willow rust Melampsora larici‐epitea using two sets of samples of a willow clone in a short‐rotation coppice planting. The first set was collected from a plot (short strip) in 1998, 1999 and 2000 and the second from another plot (long strip) in 2000. In all, 228 S. filum isolates were typed, 139 AFLP loci scored and 54 AFLP genotypes identified. In the short strip, genotypes sampled in 1998 were no longer detected in subsequent years and genotype diversity fluctuated (0·25–0·68) over the years, indicating that migration had a major impact on the genotype structure. Two distinct groups (average Nei and Li's similarity coefficient between the groups = 0·047) were identified. The group B genotypes were sampled only in 2000. Within the groups, the average similarities were > 0·96. Both the index of association test and the parsimony tree length permutation test suggest that there was a significant clonality in group A while recombination cannot be ruled out in group B. Localized clusters of AFLP genotypes were detected using the software SaTScan that is based on the spatial scan statistic. Possible mechanisms involved in the spread of S. filum in willow coppice plantations are discussed.
Potential physical and chemical barriers to infection by the burrowing nematode Radopholus similis in roots of susceptible and resistant banana (Musa spp.)
Authors: Wuyts N. , Lognay G. , Verscheure M. , Marlier M. , De Waele D. , Swennen R. 
Published: March 2007

Resistance in banana roots against the burrowing nematode Radopholus similis has been correlated in the past with the phenylpropanoid pathway of secondary metabolism, but quantitative chemical analyses to support histological data are lacking. Therefore, healthy and infected roots of two susceptible (Grande naine and Obino l’ewai) and three resistant cultivars (Yangambi km5, Pisang jari buaya and Calcutta 4) were extracted and chemically analysed for their lignin content and phenylpropanoid profile using a quantitative lignin assay, high performance liquid chromatography and liquid chromatography/mass spectrometry. Through histochemical staining phenylpropanoids were localized in root tissue. Compared to the susceptible cultivars, the resistant cultivars had constitutively significantly higher levels of lignin in the vascular bundle and cell‐wall bound ferulic acid esters in the cortex. Infection‐induced lignification was observed in the vascular bundles of all cultivars. The catecholamine dopamine was identified as a major metabolite in banana roots. Levels varied from 2·8 to 8·4 mg per g root fresh weight and were significantly higher in the resistant cultivars. Other compounds, tentatively identified as anthocyanidin‐related, were present in high quantities and may, besides dopamine, make up the substrates for polyphenol oxidation products in necrotic tissue.
Do cuckoos choose nests of great reed warblers on the basis of host egg appearance?
Authors: CHERRY M. I. , BENNETT A. T. D. , MOSKÁT C. 
Published: March 2007

AbstractPrevailing theory assumes cuckoos lay at random among host nests within a population, although it has been suggested that cuckoos could choose large nests and relatively active pairs within host populations. We tested the hypothesis that egg matching could be improved by cuckoos choosing nests in which host eggs more closely match their own, by assessing matching and monitoring nest fate in great reed warblers naturally or experimentally parasitized by eggs of European cuckoos. A positive correlation between cuckoo and host egg visual features suggests that cuckoos do not lay at random within a population, but choose nests and this improves egg matching: naturally parasitized cuckoo eggs were more similar to host eggs as perceived by humans and as measured by spectrophotometry. Our results suggest a hitherto overlooked step in cuckoo–host evolutionary arms races, and have nontrivial implications for the common experimental practice of artificially parasitizing clutches.
The genetic architecture of a niche: variation and covariation in host use traits in the Colorado potato beetle
Authors: FORISTER M. L. , EHMER A. G. , FUTUYMA D. J. 
Published: March 2007

AbstractThe genetic basis of host plant use by phytophagous insects can provide insight into the evolution of ecological niches, especially phenomena such as specialization and phylogenetic conservatism. We carried out a quantitative genetic analysis of multiple host use traits, estimated on five species of host plants, in the Colorado potato beetle,Leptinotarsa decemlineata(Coleoptera: Chrysomelidae). Mean values of all characters varied among host plants, providing evidence that adaptation to plants may require evolution of both behavioral (preference) and post‐ingestive physiological (performance) characteristics. Significant additive genetic variation was detected for several characters on several hosts, but not in the capacity to use the two major hosts, a pattern that might be caused by directional selection. No negative genetic correlations across hosts were detected for any ‘performance’ traits, i.e. we found no evidence of trade‐offs in fitness on different plants. Larval consumption was positively genetically correlated across host plants, suggesting that diet generalization might evolve as a distinct trait, rather than by independent evolution of feeding responses to each plant species, but several other traits did not show this pattern. We explored genetic correlations among traits expressed on a given plant species, in a first effort to shed light on the number of independent traits that may evolve in response to selection for host–plant utilization. Most traits were not correlated with each other, implying that adaptation to a novel potential host could be a complex, multidimensional ‘character’ that might constrain adaptation and contribute to the pronounced ecological specialization and the phylogenetic niche conservatism that characterize many clades of phytophagous insects.
Food availability affects the maternal transfer of androgens and antibodies into eggs of a colonial seabird
Authors: GASPARINI J. , BOULINIER T. , GILL V. A. , GIL D. , HATCH S. A. , ROULIN A. 
Published: March 2007

AbstractMothers can improve the quality of their offspring by increasing the level of certain components in their eggs. To examine whether or not mothers increase deposition of such components in eggs as a function of food availability, we food‐supplemented black‐legged kittiwake females (Rissa tridactyla) before and during egg laying and compared deposition of androgens and antibodies into eggs of first and experimentally induced replacement clutches. Food‐supplemented females transferred lower amounts of androgens and antibodies into eggs of induced replacement clutches than did non‐food‐supplemented mothers, whereas first clutches presented no differences between treatments. Our results suggest that when females are in lower condition, they transfer more androgens and antibodies into eggs to facilitate chick development despite potential long‐term costs for juveniles. Females in prime condition may avoid these potential long‐term costs because they can provide their chicks with more and higher quality resources.
Condition‐dependent expression of red colour differs between stickleback species
Authors: BOUGHMAN J. W. 
Published: March 2007

AbstractSexual isolation may arise when male mating traits and female preferences differ between species. Such divergence in mating traits is likely to occur when the strength or targets of sexual selection differ. Therefore, by comparing the traits under sexual selection in closely related species and the nature of preference for those traits, we can gain insight into when sexual selection contributes to sexual isolation and how it does so. Collecting these data is no easy undertaking. To simplify this comparison, I use the presence and extent of condition dependence in traits to determine whether directional sexual selection is acting on them. Condition dependence thus serves as a signature of sexual selection. I investigate differences in sexual selection on red nuptial colour in limnetic–benthic species pairs of three‐spined sticklebacks. I evaluate condition dependence by comparing the strength of the relationship between colour and condition, and the magnitude of variance in red nuptial colour to other colour traits and to nonsexual traits. I find that limnetic males have strong condition‐dependent expression of red nuptial colour whereas benthic males have at most weak condition‐dependent expression. Ancestral anadromous males show no condition dependence. This suggests that colour is under strong directional sexual selection only in limnetics and that this is the derived state. Moreover, I find that the strength of female preference for red is related to the extent of condition dependence. The extent of condition dependence is also associated with the importance of colour differences to mate recognition. These results show that differences between these species in the action of sexual selection underlie their sexual isolation.
Inbreeding depression along a life‐history continuum in the great tit
Authors: SZULKIN M. , GARANT D. , MCCLEERY R. H. , SHELDON B. C. 
Published: March 2007

AbstractInbreeding resulting from the mating of two related individuals can reduce the fitness of their progeny. However, quantifying inbreeding depression in wild populations is challenging, requiring large sample sizes, detailed knowledge of life histories and study over many generations. Here we report analyses of the effects of close inbreeding, based on observations of mating between relatives, in a large, free‐living noninsular great tit (Parus major) population monitored over 41 years. Although mating between close relatives (f ≥ 0.125) was rare (1.0–2.6% of matings, depending on data set restrictiveness), we found pronounced inbreeding depression, which translated into reduced hatching success, fledging success, recruitment to the breeding population and production of grand offspring. An inbred mating at f = 0.25 had a 39% reduction in fitness relative to that of an outbred nest, when calculated in terms of recruitment success, and a 55% reduction in the number of fledged grand offspring. Our data show that inbreeding depression acts independently at each life‐history stage in this population, and hence suggest that estimates of the fitness costs of inbreeding must focus on the entire life cycle.
Groundnut ringspot virus: an Emerging Tospovirus Inducing Disease in Peanut Crops
Authors: De Breuil S. , Abad J. A. , Nome C. F. , Giolitti F. J. , Lambertini P. L. , Lenardon S. 
Published: March 2007

AbstractPeanut (Arachis hypogaea L.) plants showing Tospovirus‐like symptoms were observed in Córdoba province (central Argentina). Peanut plants were collected and tested to identify the causal agent. Tospovirus‐like particles were observed by electron microscopy and Groundnut ringspot virus (GRSV) was identified by double antibody sandwich‐enzyme‐linked immunosorbent assay (DAS‐ELISA) and reverse transcription‐polymerase chain reaction (RT‐PCR). Partial nucleotide and deduced amino acid sequences of the nucleocapsid (N) gene indicated a high degree of identity with other GRSV sequences. This is the first report of the GRSV occurrence on peanuts in Argentina.
First Report of Tomato Yellow Leaf Curl Virus‐Israel Species Infecting Tomato, Pepper and Bean in Tunisia
Authors: Gharsallah Chouchane S. , Gorsane F. , Nakhla M. K. , Maxwell D. P. , Marrakchi M. , Fakhfakh H. 
Published: March 2007

AbstractTomato yellow leaf curl virus disease (TYLCVD) has been observed in Tunisia for more than 20 years. Until year 2004, only the Tomato yellow leaf curl Sardinia virus‐Sicily (TYLCSV‐[Sic]) was detected in tomato, pepper and bean crops. In the Sahel region, some tomato samples showing severe TYLCVD symptoms were collected from greenhouses in 2004 and 2005. Typing of these isolates revealed for the first time the presence of the TYLCV Israel in Tunisia. This result was confirmed by using several sets of specific primers and by sequencing. This species has also been detected on pepper and bean collected from fields in the same region. The sequencing of a tomato and a bean isolate showed that they both share more than 97% of sequence identity with the TYLCV from Dominican Republic (AF024715). The TYLCV has been found in single and mixed infection with the TYLCSV‐[Sic].
Working in a training garden: Experiences of patients with neurological damage
Authors: Jonasson Inger , Marklund Bertil , Hildingh Cathrine 
Published: March 2007

Aim:  The aim of this study was to describe patients’ experiences of working in a training garden after neurological damage. Methods:  The study employs a qualitative method with a phenomenographic approach. Interviews with 14 patients attending outpatient rehabilitation were conducted. The interview consisted of open‐ended questions based on an interview guide covering: the activity, the training, its value and the environment. Results:  The study revealed that activities in a training garden were experienced as beneficial, productive, voluntary and complicated. Certain conditions are necessary for performance and for drawing benefit from the activities. Conclusions:  The results of this study may be of benefit in clinical work and may also apply to other groups of patients. Further research is needed on training gardens to enhance knowledge of suitable activities for different groups of patients to be used in the design of intervention programs.
Use of a geographic information system to explore spatial variation in pathogen virulence and the implications for biological control of locusts and grasshoppers
Authors: Klass Justine I. , Blanford Simon , Thomas Matthew B. 
Published: March 2007

Abstract1 In a previous study, we developed a model to predict the effects of temperature on performance of a fungus‐based biopesticide for controlling locusts and grasshoppers. Currently, the model is limited to predicting rate of mortality after a spray application at site‐specific locations. The aim of the present study is to enhance the utility of this model by linking it with meteorological station data in a geographic information system (GIS) framework to investigate the spatial variation in the performance of the biopesticide.2 The model provides maps that define spatial variation in pathogen virulence (measured as LT90 for a treated population) across different regions. The model was used to explore the variation in biopesticide performance against four economically important pest species: Moroccan locust Dociostaurus maroccanus in Spain; brown locust Locustana pardalina in South Africa; red locust Nomadacris septemfasciata in Zambia and; Senegalese grasshopper Oedaleus senegalensis in Niger.3 Model outputs for the different species were partially validated against data from field trials. The models provided good estimates of time to 90% mortality for five out of six independent comparisons. There was also good agreement between the spatial model and equivalent output from the site‐specific model.4 Simulations of virulence against N. septemfasciata in Zambia indicated very uniform, rapid mortality with LT90 throughout the country generally less than 11 days. Pathogen‐induced mortality of O. senegalensis in Niger was predicted to be slightly slower and more variable with mortality fastest in the southern regions (< 15 days) and slowing to the north of the country (16–20 days). For both L. pardalina in South Africa and D. maroccanus in Spain, the model revealed highly variable patterns of mortality with LT90 ranging from < 15 days in some areas to > 30 days in others.5 The implications of these different patterns of variability for the development of optimum use strategies for the various species and the basic understanding of the ecology and evolution of insect–pathogen interactions are discussed.
Metagenomic approach to the study of halophages: the environmental halophage 1
Authors: Santos Fernando , Meyerdierks Anke , Peña Arantxa , Rosselló‐Mora Ramon , Amann Rudolf , Antón Josefa 
Published: March 2007

SummaryHypersaline environments, such as crystallizer ponds of solar salterns, show one of the highest concentration of viruses reported for aquatic systems. All the halophages characterized so far are isolates obtained by cultivation from described haloarchaeal species that have only low abundance in the environment. We employed a culture‐independent metagenomic approach to analyse for the first time complete genomes in the halophage community and explored the in situ diversity by transmission electron microscopy and pulsed‐field gel electrophoresis. We report the genomic sequence of a not yet isolated halophage (named as environmental halophage 1 ‘EHP‐1′) whose DNA was obtained from crystallizer samples with a salinity of 31%. The sequenced genome has a size of 35 kb and a G + C content around 51%. The G + C content is lower than that of previously characterized halophages. However, G + C content and codon usage in EHP‐1 are similar to the recently cultivated and sequenced Haloquadratum walsbyi, the major prokaryotic component in solar salterns around the world. Forty open reading frames have been predicted, including genes that putatively code for proteins involved in DNA replication (ribonucleotide reductases, thymidylate kinase) normally found in lytic viruses.
Distribution, genetic richness and phage sensitivity of Vibrio spp. from coastal British Columbia
Authors: Comeau André M. , Suttle Curtis A. 
Published: March 2007

SummaryThis study examined the distribution, susceptibility to viral infection and genetic diversity of Vibrio spp. in the coastal waters and sediments of British Columbia during summer (July and August). Abundances of presumptive Vibrio spp. ranged from 1.5 to 346 ml−1 within the water column (1–291 m); whereas, abundances at the water–sediment interface were much higher (up to ∼3 × 104Vibrio spp. cc−1), and decreased with sediment depth (down to 30 cm). The genetic diversity of Vibrio spp. isolates was not tied to the location from which they originated and was only influenced in a minor way by the type of environment. However, the environment had a greater effect on phage‐typing patterns. Vibrio parahaemolyticus isolates from environments with high abundances of cells (sediments and oysters) were generally more susceptible to viral infection than those from the water column which were highly resistant. Therefore, although Vibrio spp. were widespread in the areas investigated, the results show that there is segregation of bacterial host strains in different environments, under differing selection pressures, which ultimately will affect in situ phage production.
Effects of insulin vs. glibenclamide in recently diagnosed patients with type 2 diabetes: a 4‐year follow‐up
Authors: Alvarsson M. , Sundkvist G. , Lager I. , Berntorp K. , Fernqvist‐Forbes E. , Steen L. , Örn T. , Holberg M. A. , Kirksæther N. , Grill V. 
Published: March 2007

Aim:  To compare effects of early insulin vs. glibenclamide treatment on beta‐cell function, metabolic control and quality of life (QL) in recently diagnosed patients with type 2 diabetes.Methods:  Forty‐nine patients with type 2 diabetes diagnosed 0–2 years before inclusion were randomized to two daily injections of premixed 30% soluble and 70% NPH insulin or glibenclamide at six diabetic clinics in Sweden. C‐peptide–glucagon tests were performed yearly after 3 days of withdrawal of treatment.Results:  Thirty‐four patients completed 4 years of study. Daily dose of insulin was increased from 20.4 ± 1.8 U at year 1 to 26.1 ± 2.9 U at year 4 (p = 0.005). Glibenclamide dosage increased from 2.7 ± 0.4 mg at year 1 to 4.5 ± 0.8 mg at year 4 (p = 0.02). Weight increased more in insulin than in glibenclamide treated (+4.4 ± 0.8 vs. +0.3 ± 1.0 kg, p < 0.005). Following short‐term withdrawal of treatment, the C‐peptide responses to glucagon were significantly higher in the insulin vs. glibenclamide group at years 1 (p < 0.01) and 2 (p < 0.02). HbA1c improved identical during the first year but thereafter deteriorated in the glibenclamide group (p < 0.005 for difference at year 4). Ratios of proinsulin to insulin were higher during treatment in glibenclamide‐ vs. insulin‐treated patients after year 2. QL after 4 years as measured by the MOS 36‐item Short‐Form Health Survey (SF‐36) form was not significantly altered.Conclusions:  In a 4‐year perspective, beta‐cell function deteriorated in both groups. However, deterioration occurred faster in the glibenclamide group, indicating that alleviating demands on secretion by insulin treatment is beneficial.