bluuebunny/crossref_metadata_2025 huggingface dataset:
Interference of chlorate and chlorite with nitrate reduction in resting cells of Paracoccus denitrificans
Authors: Kučera Igor
Published: December 2006

When grown anaerobically on a succinate+nitrate (SN) medium,Paracoccus denitrificansforms the membrane-bound, cytoplasmically oriented, chlorate-reducing nitrate reductase Nar, while the periplasmic enzyme Nap is expressed during aerobic growth on butyrate+oxygen (BO) medium. Preincubation of SN cells with chlorate produced a concentration-dependent decrease in nitrate utilization, which could be ascribed to Nar inactivation. Toluenization rendered Nar less sensitive to chlorate, but more sensitive to chlorite, suggesting that the latter compound may be the true inactivator. The Nap enzyme of BO cells was inactivated by both chlorate and chlorite at concentrations that were at least two orders of magnitude lower than those shown to affect Nar. Partial purification of Nap resulted in insensitivity to chlorate and diminished sensitivity to chlorite. Azide was specific for SN cells in protecting nitrate reductase against chlorate attack, the protective effect of nitrate being more pronounced in BO cells. The results are discussed in terms of different metabolic activation of chlorine oxoanions in both types of cells, and limited permeation of chlorite across the cell membrane.
Identification of promoter elements responsible for the regulation of MDR1 from Candida albicans, a major facilitator transporter involved in azole resistance
Authors: Rognon Bénédicte , Kozovska Zuzana , Coste Alix T. , Pardini Giacomo , Sanglard Dominique
Published: December 2006

Upregulation of theMDR1(multidrugresistance 1) gene is involved in the development of resistance to antifungal agents in clinical isolates of the pathogenCandida albicans. To better understand the molecular mechanisms underlying the phenomenon, thecis-acting regulatory elements present in theMDR1promoter were characterized using aβ-galactosidase reporter system. In an azole-susceptible strain, transcription of this reporter is transiently upregulated in response to either benomyl or H2O2, whereas its expression is constitutively high in an azole-resistant strain (FR2). Twocis-acting regulatory elements within theMDR1promoter were identified that are necessary and sufficient to confer the same transcriptional responses on a heterologous promoter (CDR2). One, abenomylresponseelement (BRE), is situated at position −296 to −260 with respect to the ATG start codon. It is required for benomyl-dependentMDR1upregulation and is also necessary for constitutive high expression ofMDR1. A second element, termedH2O2responseelement (HRE), is situated at position −561 to −520. The HRE is required for H2O2-dependentMDR1upregulation, but dispensable for constitutive high expression. Two potential binding sites (TTAG/CTAA) for the bZip transcription factor Cap1p (CandidaAP-1 protein) lie within the HRE. Moreover, inactivation ofCAP1abolished the transient response to H2O2. Cap1p, which has been previously implicated in cellular responses to oxidative stress, may thus play atrans-acting and positive regulatory role in the H2O2-dependent transcription ofMDR1. A minimal BRE (−290 to −273) that is sufficient to detectin vitrosequence-specific binding of protein complexes in crude extracts prepared fromC. albicanswas also defined. Interestingly, the sequence includes a perfect match to the consensus binding sequence of Mcm1p, raising the possibility thatMDR1may be a direct target of this MADS box transcriptional activator. In conclusion, while the identity of thetrans-acting factors that bind to the BRE and HRE remains to be confirmed, the tools developed during this characterization of thecis-acting elements of theMDR1promoter should now serve to elucidate the nature of the components that modulate its activity.
Analysis of theDECREASED APICAL DOMINANCEGenes of Petunia in the Control of Axillary Branching
Authors: Simons Joanne L. , Napoli Carolyn A. , Janssen Bart J. , Plummer Kim M. , Snowden Kimberley C.
Published: December 2006

Control of branch development is a major determinant of architecture in plants. Branching in petunia (Petunia hybrida) is controlled by the DECREASED APICAL DOMINANCE (DAD) genes. Gene functions were investigated by plant grafting, morphology studies, double-mutant characterization, and gene expression analysis. Both dad1-1 and dad3 increased branching mutants can be reverted to a near-wild-type phenotype by grafting to a wild-type or a dad2 mutant root stock, indicating that both genes affect the production of a graft-transmissible substance that controls branching. Expression of the DAD1 gene in the stems of grafted plants, detected by quantitative reverse transcription-polymerase chain reaction correlates with the branching phenotype of the plants. The dad2-1 mutant cannot be reverted by grafting, indicating that this gene acts predominantly in the shoot of the plant. Double-mutant analysis indicates that the DAD2 gene acts in the same pathway as the DAD1 and DAD3 genes because the dad1-1dad2-1 and dad2-1dad3 double mutants are indistinguishable from the dad2-1 mutant. However, the dad1-1dad3 double mutant has an additive phenotype, with decreased height of the plants, delayed flowering, and reduced germination rates compared to the single mutants. This result, together with the observation that the dad1-1 and dad3 mutants cannot be reverted by grafting to each other, suggests that the DAD1 and DAD3 genes act in the same pathway, but not in a simple stepwise fashion.
Gradual Soil Water Depletion Results in Reversible Changes of Gene Expression, Protein Profiles, Ecophysiology, and Growth Performance in Populus euphratica, a Poplar Growing in Arid Regions
Authors: Bogeat-Triboulot Marie-Béatrice , Brosché Mikael , Renaut Jenny , Jouve Laurent , Le Thiec Didier , Fayyaz Payam , Vinocur Basia , Witters Erwin , Laukens Kris , Teichmann Thomas , Altman Arie , Hausman Jean-François , Polle Andrea , Kangasjärvi Jaakko , Dreyer Erwin
Published: December 2006

The responses of Populus euphratica Oliv. plants to soil water deficit were assessed by analyzing gene expression, protein profiles, and several plant performance criteria to understand the acclimation of plants to soil water deficit. Young, vegetatively propagated plants originating from an arid, saline field site were submitted to a gradually increasing water deficit for 4 weeks in a greenhouse and were allowed to recover for 10 d after full reirrigation. Time-dependent changes and intensity of the perturbations induced in shoot and root growth, xylem anatomy, gas exchange, and water status were recorded. The expression profiles of approximately 6,340 genes and of proteins and metabolites (pigments, soluble carbohydrates, and oxidative compounds) were also recorded in mature leaves and in roots (gene expression only) at four stress levels and after recovery. Drought successively induced shoot growth cessation, stomatal closure, moderate increases in oxidative stress-related compounds, loss of CO2 assimilation, and root growth reduction. These effects were almost fully reversible, indicating that acclimation was dominant over injury. The physiological responses were paralleled by fully reversible transcriptional changes, including only 1.5% of the genes on the array. Protein profiles displayed greater changes than transcript levels. Among the identified proteins for which expressed sequence tags were present on the array, no correlation was found between transcript and protein abundance. Acclimation to water deficit involves the regulation of different networks of genes in roots and shoots. Such diverse requirements for protecting and maintaining the function of different plant organs may render plant engineering or breeding toward improved drought tolerance more complex than previously anticipated.
Spatial Variation of Deuterium Enrichment in Bulk Water of Snowgum Leaves
Authors: Šantrůček Jiří , Květoň Jiří , Šetlík Jiří , Bulíčková Lenka
Published: December 2006

Deuterium enrichment of bulk water was measured and modeled in snowgum (Eucalyptus pauciflora Sieber ex Sprengel) leaves grown under contrasting air and soil humidity in arid and wet conditions in a glasshouse. A map of the enrichment was constructed with a resolution of 4 mm by using a newly designed cryodistillation method. There was progressively increasing enrichment in both longitudinal (along the leaf midrib) and transversal (perpendicular to the midrib) directions, most pronounced in the arid-grown leaf. The whole-leaf average of the enrichment was well below the value estimated by the Craig-Gordon model. The discrepancy between model and measurements persisted when the estimates were carried out separately for the leaf base and tip, which differed in temperature and stomatal conductance. The discrepancy was proportional to the transpiration rate, indicating the significance of diffusion-advection interplay (Péclet effect) of deuterium-containing water molecules in small veins close to the evaporating sites in the leaf. Combined Craig-Gordon and desert-river models, with or without the Péclet number, P, were used for predicting the leaf longitudinal enrichment. The predictions without P overestimated the measured values of δdeuterium. Fixed P value partially improved the coincidence. We suggest that P should vary along the leaf length l to reconcile the modeled data with observations of longitudinal enrichment. Local values of P, P(l), integrating the upstream fraction of water used or the leaf area, substantially improved the model predictions.
Localization of Mechanisms Involved in Hydropassive and Hydroactive Stomatal Responses of Sambucus nigra to Dry Air
Authors: Kaiser Hartmut , Legner Nicole
Published: December 2006

The response of stomata to a reduction of air humidity is composed of a hydropassive opening followed by active closure. Whereas the mechanisms behind the hydropassive opening are largely understood, the location and physiological basis of the sensing mechanisms leading to active closure are not yet known. This study attempts to evaluate the importance of a single pore's transpiration on its own response and that of adjacent pores. Selected stomata on attached intact leaves of Sambucus nigra were sealed with mineral oil and the response to a reduction of humidity was continuously observed in situ. Blocking a pore's transpiration had no appreciable effect on hydropassive opening and subsequent stomatal closure. If the adjacent stomata were additionally sealed, the closing response was reduced, but not the hydropassive opening. On the other hand, sealing the entire leaf surface, except a small area including the observed stomata, also reduced stomatal closure. These results indicate that strictly local processes triggered by a pore's own transpiration are not required to induce stomatal closure. To describe the effect of one pore's transpiration on the hydropassive and hydroactive responses of neighboring stomata, a simple spatial model was constructed. It suggests that 90% of the closing effect covers an area of approximately 0.5 mm2, whereas the effect on hydropassive opening affects an area of approximately 1 mm2. This divergence may suggest mechanisms other than or in addition to those involving changes of local leaf water potential.
Recessiveness and Dominance in Barley Mutants Deficient in Mg-Chelatase Subunit D, an AAA Protein Involved in Chlorophyll Biosynthesis
Authors: Axelsson Eva , Lundqvist Joakim , Sawicki Artur , Nilsson Sara , Schröder Ingrid , Al-Karadaghi Salam , Willows Robert D. , Hansson Mats
Published: December 2006

Mg-chelatase catalyzes the insertion of Mg2+ into protoporphyrin IX at the first committed step of the chlorophyll biosynthetic pathway. It consists of three subunits: I, D, and H. The I subunit belongs to the AAA protein superfamily (ATPases associated with various cellular activities) that is known to form hexameric ring structures in an ATP-dependant fashion. Dominant mutations in the I subunit revealed that it functions in a cooperative manner. We demonstrated that the D subunit forms ATP-independent oligomeric structures and should also be classified as an AAA protein. Furthermore, we addressed the question of cooperativity of the D subunit with barley (Hordeum vulgare) mutant analyses. The recessive behavior in vivo was explained by the absence of mutant proteins in the barley cell. Analogous mutations in Rhodobacter capsulatus and the resulting D proteins were studied in vitro. Mixtures of wild-type and mutant R. capsulatus D subunits showed a lower activity compared with wild-type subunits alone. Thus, the mutant D subunits displayed dominant behavior in vitro, revealing cooperativity between the D subunits in the oligomeric state. We propose a model where the D oligomer forms a platform for the stepwise assembly of the I subunits. The cooperative behavior suggests that the D oligomer takes an active part in the conformational dynamics between the subunits of the enzyme.
Molecular Identification and Physiological Characterization of a Novel Monosaccharide Transporter from Arabidopsis Involved in Vacuolar Sugar Transport
Authors: Wormit Alexandra , Trentmann Oliver , Feifer Ingmar , Lohr Christian , Tjaden Joachim , Meyer Stefan , Schmidt Ulrike , Martinoia Enrico , Neuhaus H. Ekkehard
Published: December 2006

The tonoplast monosaccharide transporter (TMT) family comprises three isoforms in Arabidopsis thaliana, and TMT–green fluorescent protein fusion proteins are targeted to the vacuolar membrane. TMT promoter–β-glucuronidase plants revealed that the TONOPLAST MONOSACCHARIDE TRANSPORTER1 (TMT1) and TMT2 genes exhibit a tissue- and cell type–specific expression pattern, whereas TMT3 is only weakly expressed. TMT1 and TMT2 expression is induced by drought, salt, and cold treatments and by sugar. During cold adaptation, tmt knockout lines accumulated less glucose and fructose compared with wild-type plants, whereas no differences were observed for sucrose. Cold adaptation of wild-type plants substantially promoted glucose uptake into isolated leaf mesophyll vacuoles. Glucose uptake into isolated vacuoles was inhibited by NH4  +, fructose, and phlorizin, indicating that transport is energy-dependent and that both glucose and fructose were taken up by the same carrier. Glucose import into vacuoles from two cold-induced tmt1 knockout lines or from triple knockout plants was substantially lower than into corresponding wild-type vacuoles. Monosaccharide feeding into leaf discs revealed the strongest response to sugar in tmt1 knockout lines compared with wild-type plants, suggesting that TMT1 is required for cytosolic glucose homeostasis. Our results indicate that TMT1 is involved in vacuolar monosaccharide transport and plays a major role during stress responses.
ArabidopsisDCP2, DCP1, and VARICOSE Form a Decapping Complex Required for Postembryonic Development
Authors: Xu Jun , Yang Jun-Yi , Niu Qi-Wen , Chua Nam-Hai
Published: December 2006

mRNA turnover in eukaryotes involves the removal of m7GDP from the 5′ end. This decapping reaction is mediated by a protein complex well characterized in yeast and human but not in plants. The function of the decapping complex in the development of multicellular organisms is also poorly understood. Here, we show that Arabidopsis thaliana DCP2 can generate from capped mRNAs, m7GDP, and 5′-phosphorylated mRNAs in vitro and that this decapping activity requires an active Nudix domain. DCP2 interacts in vitro and in vivo with DCP1 and VARICOSE (VCS), an Arabidopsis homolog of human Hedls/Ge-1. Moreover, the interacting proteins stimulate DCP2 activity, suggesting that the three proteins operate as a decapping complex. Consistent with their role in mRNA decay, DCP1, DCP2, and VCS colocalize in cytoplasmic foci, which are putative Arabidopsis processing bodies. Compared with the wild type, null mutants of DCP1, DCP2, and VCS accumulate capped mRNAs with a reduced degradation rate. These mutants also share a similar lethal phenotype at the seedling cotyledon stage, with disorganized veins, swollen root hairs, and altered epidermal cell morphology. We conclude that mRNA turnover mediated by the decapping complex is required for postembryonic development in Arabidopsis.
Isolation and characterization of the mating type locus of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana
Authors: CONDE‐FERRÁEZ LAURA , WAALWIJK CEES , CANTO‐CANCHÉ BLONDY B. , KEMA GERT H. J. , CROUS PEDRO W. , JAMES ANDREW C. , ABELN EDWIN C. A.
Published: December 2006

Idiomorphs mat1‐1 and mat1‐2 from Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana, were isolated. Degenerate oligos were used to amplify the HMG box of the mat1‐2 idiomorph from M. fijiensis, showing homology with the HMG box of Mycosphaerella graminicola. Using a DNA walking strategy, anchored on the DNA lyase gene towards the HMG box, a 9‐kb‐long region of mat1‐2 was obtained. A 5‐kb fragment from the mat1‐1 region was obtained by long‐range PCR using primers on the flanking regions, which have close to 100% identity between both idiomorphs. High‐identity (77–89%), inverted regions within both idiomorphs were found, which suggest unique inversion events, which have not been found before, and that could have been significant in the evolution of this species. The predicted genes showed the conserved introns in both idiomorphs as well as an additional intron within the alpha box. The implications for the evolution of species in the Mycosphaerella complex on banana are discussed.
Inaccuracy of high‐performance liquid chromatography estimation of haemoglobin F in the presence of increased haemoglobin A1c
Authors: GREY V. , WILKINSON M. , PHELAN L. , HUGHES C. , BAIN B. J.
Published: December 2006

Increasingly high‐performance liquid chromatography is being used for identification and quantification of normal and variant haemoglobins. In many laboratories, the Beta Thal Short programme of the Bio‐Rad Variant II instrument is used for this purpose. We noted that a factitious elevation of haemoglobin F was sometimes observed in diabetic patients and therefore carried out a systematic study of this phenomenon. We found discrepant results in 41% of samples from diabetic patients but in no normal volunteers. This factitious elevation could be predicted from a retention time for haemoglobin F of more than 1.15 min, the normal retention time being 1.08–1.15 min. Haemoglobinopathy laboratories need to be alert to the possibility of this erroneous result.
Methicillin‐resistant Staphylococcus aureus hepatic abscess in a patient with sickle‐cell disease
Authors: MANCAO M. , ESTRADA B. , WILSON F. , FIGAROLA M. , WESENBERG R.
Published: December 2006

We report a case of a 16‐year‐old female patient with sickle‐cell disease with a liver abscess secondary to methicillin‐resistant Staphylococcus aureus (MRSA). She had initially presented with jaundice and abdominal pain and subsequently underwent endoscopic retrograde cholangio‐pancreaticography followed by laparoscopic cholecystectomy for removal of gallstones. However, post‐cholecystectomy she presented with generalized abdominal pain and computed tomography scan of the abdomen revealed a liver abscess. A pigtail catheter was inserted into the abscess and culture of the aspirate yielded MRSA (susceptibility pattern of the organism was compatible with community‐acquired MRSA). She was treated with intravenous clindamycin for 6 weeks with complete resolution of the abscess.
Immunoflow cytometry compared with PCR for the identification of clonality in FNAs of T‐cell‐rich B‐cell lymphomas
Authors: Mayall F. , Johnson S.
Published: December 2006

Objective:  The study aimed to compare the utility of immunoflow cytometry (IFC) with two IgH polymerase chain reaction (PCR) methods for the identification of clonality in fine needle aspirations (FNAs) from T‐cell‐rich B‐cell lymphomas (TCRBCLs).

Methods:  Ten cases of TCRBCLs were identified in which IFC had been performed according to our previously described method. Seven of these were cases in which the original diagnosis had been made by FNA cytology with IFC and cell block immunohistochemistry (IHC). The remaining three cases only had biopsies with histology, IFC and IHC. Formalin‐fixed paraffin‐embedded FNA cell block or histology tissue from these specimens had also been submitted for IgH PCR clonality studies using primers FR2a/VLJH and primers FR3a/VLJH. The results were reviewed and compared.

Results:  All 10 case demonstrated B‐cell clonality for at least one of the primer sets on PCR, but none showed light chain restriction on IFC. All TCRBCLs were positive for CD20 and CD79a but negative for CD10 and BCl‐2. They were also consistently negative for CD22, CD23, CD5, CD43, ALK‐1, cyclin D1 and CD30.

Conclusions:  If IgH PCR clonality assays had a turnaround time of 1 or 2 days, there might be a strong case for these studies supporting or even replacing IFC, in the FNA diagnosis of lymphoid lesions.
Maternal attendance and the maintenance of family groups in common earwigs (Forficula auricularia): a field experiment
Authors: KÖLLIKER MATHIAS , VANCASSEL MICHEL
Published: December 2006

Abstract 1. Understanding the evolution of subsocial behaviour and parental care requires experimental tests of the functional significance of such behaviours and the role of tending parents in the maintenance of family groups. Studies in subsocial insects addressing these issues experimentally and in the field are still relatively rare.

2. In such a field experiment, it is demonstrated here that the presence of tending females enhances the maintenance of family groups in common earwigs, Forficula auricularia (Dermaptera; Forficulidae). Experimental removal of tending mothers resulted in substantially decreased recovery of occupied nest burrows and larvae. This effect may have been because of decreased survival among experimental larvae, although a possible role for enhanced larval dispersal could not be fully ruled out.

3. Experimental (motherless) larvae were partly observed in family groups with a tending female, in both experimental and control nest burrows, suggesting that these larvae had been adopted by family groups moving to new nest burrows, and/or that experimental larvae may have actively joined other family groups.

4. This study demonstrates under field conditions the functional importance of maternal attendance for the maintenance of family groups in common earwigs, and suggests that adoption and clutch‐joining are factors affecting the social structure of this species.
Effect of Novaluron (Rimon® 10 EC) on the mosquitoes Anopheles albimanus, Anopheles pseudopunctipennis, Aedes aegypti, Aedes albopictus and Culex quinquefasciatus from Chiapas, Mexico
Authors: ARREDONDO‐JIMÉNEZ J. I. , VALDEZ‐DELGADO K. M.
Published: December 2006

Abstract Dengue fever is a serious problem in Mexico and vector control has not been effective enough at preventing outbreaks. Malaria is largely under control, but it is important that new control measures continue to be developed. Novaluron, a novel host‐specific insect growth regulator and chitin synthesis inhibitor, has proved to be effective against agricultural pests, but its efficacy against larval mosquito vectors under field conditions remains unknown. In accordance with the World Health Organization Pesticide Evaluation Scheme, phase I, II and III studies were conducted to evaluate the efficacy and residual effect of Novaluron (Rimon® 10 EC, Makhteshim, Beer‐Sheva, Israel) on the malaria vectors Anopheles albimanus Wiedemann (Diptera: Culicidae) and Anopheles pseudopunctipennis Theobald, the dengue vectors Aedes aegypti (L) and Aedes albopictus Skuse and the nuisance mosquito Culex quinquefasciatus Say. Laboratory susceptibility tests yielded diagnostic concentrations for all five target species. Field trials to identify the optimum field dosage of Novaluron against Anopheles mosquitoes were carried out under semi‐natural conditions in artificial plots and in vessels with wild mosquitoes. Efficacy was measured by monitoring mortality of larvae and pupae and the percentage of inhibition of emergence from floating cages. Dosages of Novaluron for field tests were based on pupal LC99 (lethal concentration 99%) of An. pseudopunctipennis (0.166 mg/L) in plots and average pupal LC99 of Ae. aegypti and Ae. albopictus (0.55 mg/L). At all dosages tested, Novaluron significantly reduced larval populations of An. albimanus, Culex coronator Dyar & Knab, Ae. albopictus and Cx. quinquefasciatus by ∼ 90%, inhibited adult emergence of An. albimanus and An. pseudopunctipennis by ∼ 97% for almost 4 months in experimental plots, and inhibited adult emergence of Ae. aegypti and Ae. albopictus by ∼ 97% for up to 14 weeks. Recommended dosages of Novaluron for non‐container breeding and container breeding mosquitoes are 0.166 mg/L and 0.55 mg/L, respectively. Overall, the residual effect was more sustained than that of temephos. The lowest dosage of Novaluron had less of an impact on non‐target organisms than did temephos. Small‐scale field trials in natural breeding sites treated with Novaluron at 0.6 L/ha eliminated adult emergence of An. albimanus and Cx. coronator for 8 weeks. For phase III studies, Novaluron was tested at the local and village levels, applying the optimum field rate to all natural breeding habitats within 1 km of a pair of neighbouring villages. Village‐scale trials of Novaluron at 0.6 L/ha reduced An. albimanus larval populations for at least 8 weeks and, more importantly, sharply reduced the densities of adult host‐seeking mosquitoes approaching houses. We conclude that Novaluron is effective and environmentally safer than temephos.
Blood‐feeding behaviour of the malarial mosquitoAnopheles arabiensis: implications for vector control
Authors: TIRADOS I. , COSTANTINI C. , GIBSON G. , TORR S. J.
Published: December 2006

AbstractFeeding behaviour of the malaria vectorAnopheles arabiensisPatton (Diptera: Culicidae) was monitored for 12 months (March 2003−February 2004) in the Konso District of southern Ethiopia (5°15′N, 37°28′E). More than 45 000An. arabiensisfemales were collected by host‐baited sampling methods (light‐traps, human landing catches, cattle‐baited traps) and from resting sites (huts and pit shelters). In the village of Fuchucha, where the ratio of cattle : humans was 0.6 : 1, 51% of outdoor‐resting mosquitoes and 66% of those collected indoors had fed on humans, human baits outdoors caught > 2.5 times more mosquitoes than those indoors and the mean catch of mosquitoes from pit shelters was about five times that from huts. Overall, the vast majority of feeding and resting occurred outdoors. In the cattle camps of Konso, where humans slept outdoors close to their cattle, ∼ 46% of resting mosquitoes collected outdoors had fed on humans despite the high cattle : human ratio (17 : 1). In both places, relatively high proportions of bloodmeals were mixed cow + human: 22–25% at Fuchucha and 37% in the cattle camps. Anthropophily was also gauged experimentally by comparing the numbers of mosquitoes caught in odour‐baited entry traps baited with either human or cattle odour. The human‐baited trap caught about five times as many mosquitoes as the cattle‐baited one. Notwithstanding the potential pitfalls of using standard sampling devices to analyse mosquito behaviour, the results suggest that theAn. arabiensispopulation is inherently anthropophagic, but this is counterbalanced by exophagic and postprandial exophilic tendencies. Consequently, the population feeds sufficiently on humans to transmit malaria (sporozoite rates: 0.3% forPlasmodium falciparumand 0.5% forP. vivax, by detection of circumsporozoite antigen) but also takes a high proportion of meals from non‐human hosts, with 59–91% of resting mosquitoes containing blood from cattle. Hence, classical zooprophylaxis is unlikely to have a significant impact on the malaria vectorial capacity ofAn. arabiensisin Konso, whereas treating cattle with insecticide might do.
Global patterns of diversity and community structure in marine bacterioplankton
Authors: POMMIER T. , CANBÄCK B. , RIEMANN L. , BOSTRÖM K. H. , SIMU K. , LUNDBERG P. , TUNLID A. , HAGSTRÖM Å.
Published: December 2006

Because of their small size, great abundance and easy dispersal, it is often assumed that marine planktonic microorganisms have a ubiquitous distribution that prevents any structured assembly into local communities. To challenge this view, marine bacterioplankton communities from coastal waters at nine locations distributed world‐wide were examined through the use of comprehensive clone libraries of 16S ribosomal RNA genes, used as operational taxonomic units (OTU). Our survey and analyses show that there were marked differences in the composition and richness of OTUs between locations. Remarkably, the global marine bacterioplankton community showed a high degree of endemism, and conversely included few cosmopolitan OTUs. Our data were consistent with a latitudinal gradient of OTU richness. We observed a positive relationship between the relative OTU abundances and their range of occupation, i.e. cosmopolitans had the largest population sizes. Although OTU richness differed among locations, the distributions of the major taxonomic groups represented in the communities were analogous, and all local communities were similarly structured and dominated by a few OTUs showing variable taxonomic affiliations. The observed patterns of OTU richness indicate that similar evolutionary and ecological processes structured the communities. We conclude that marine bacterioplankton share many of the biogeographical and macroecological features of macroscopic organisms. The general processes behind those patterns are likely to be comparable across taxa and major global biomes.
Extensive spatial genetic structure revealed by AFLP but not SSR molecular markers in the wind‐pollinated tree, Fagus sylvatica
Authors: JUMP ALISTAIR S. , PEÑUELAS JOSEP
Published: December 2006

Studies of fine‐scale spatial genetic structure (SGS) in wind‐pollinated trees have shown that SGS is generally weak and extends over relatively short distances (less than 30–40 m) from individual trees. However, recent simulations have shown that detection of SGS is heavily dependent on both the choice of molecular markers and the strategy used to sample the studied population. Published studies may not always have used sufficient markers and/or individuals for the accurate estimation of SGS. To assess the extent of SGS within a population of the wind‐pollinated tree Fagus sylvatica, we genotyped 200 trees at six microsatellite or simple sequence repeat (SSR) loci and 250 amplified fragment length polymorphisms (AFLP) and conducted spatial analyses of pairwise kinship coefficients. We re‐sampled our data set over individuals and over loci to determine the effect of reducing the sample size and number of loci used for SGS estimation. We found that SGS estimated from AFLP markers extended nearly four times further than has been estimated before using other molecular markers in this species, indicating a persistent effect of restricted gene flow at small spatial scales. However, our SSR‐based estimate was in agreement with other published studies. Spatial genetic structure in F. sylvatica and similar wind‐pollinated trees may therefore be substantially larger than has been estimated previously. Although 100–150 AFLP loci and 150–200 individuals appear sufficient for adequately estimating SGS in our analysis, 150–200 individuals and six SSR loci may still be too few to provide a good estimation of SGS in this species.
Interplay between ecological, behavioural and historical factors in shaping the genetic structure of sympatric walleye populations (Sander vitreus)
Authors: DUPONT PIERRE‐PHILIPPE , BOURRET VINCENT , BERNATCHEZ LOUIS
Published: December 2006

Disentangling ecological, behavioural and evolutionary factors responsible for the presence of stable population structure within wild populations has long been challenging to population geneticists. This study primarily aimed at decoding population structure of wild walleye (Sander vitreus) populations of Mistassini Lake (Québec, Canada) in order to define source populations to be used for the study of spatial partitioning using individual‐based multilocus assignment methods, and decipher the dynamics of individual dispersal and resulting patterns of spatial resource partitioning and connectivity among populations. A second objective was to elucidate the relationships between biological characteristics (sex, size, age and population of origin) and an individual's probability to migrate and/or disperse. To do so, a total of 780 spawning individuals caught on five distinct spawning sites, and 1165 postspawning individuals, captured over two sampling seasons (2002–2003) were analysed by means of eight microsatellite loci. Four temporally stable walleye populations associated with distinct reproductive grounds were detected. These populations were differentially distributed among lake sectors during their feeding migration and their spatial distribution was stable over the two sampling seasons. Dispersing individuals were identified (n = 61); these revealed asymmetrical patterns of dispersal between populations, which was also confirmed by divergent admixture proportions. Regression models underlined population of origin as the only factor explaining differential dispersal of individuals among populations. An analysis of covariance (ancova) indicated that larger individuals tended to migrate from their river of origin further away in the lake relative to smaller fish. In summary, this study underlined the relevance of using individual‐based assignment methods for deciphering dynamics of connectivity among wild populations, especially regarding behavioural mechanisms such as differential spatial partitioning and dispersal responsible for the maintenance of genetic population structure.
Effect of peripheral obestatin on gastric emptying and intestinal contractility in rodents
Authors: De Smet B. , Thijs T. , Peeters T. L. , Depoortere I.
Published: December 2006

Abstract  Obestatin has recently been discovered in the rat stomach. It is encoded by the ghrelin gene and has been claimed to be a functional opponent of ghrelin and to be the natural ligand of the GPR39 receptor. The latter could not be confirmed by Holst et al. (Endocrinology, 2006). Yet, in GPR39 knockout mice, gastric emptying is accelerated. We verified the effects of obestatin on gastric emptying and intestinal contractility in rodents. Gastric emptying was measured with the 14C octanoic breath test in mice. In vitro, the effect of obestatin was studied on electrically stimulated and non‐stimulated strips from the fundus and small intestine of mice and rats. Obestatin (60, 125, 250 nmol kg−1) did not affect gastric emptying parameters (Thalf and Tlag) and did not inhibit the prokinetic effects of ghrelin. Mouse and rat intestinal and fundic smooth muscle strips did not respond to obestatin either in the absence or in the presence of electrical field stimulation. Obestatin (125 nmol kg−1) did not inhibit fasting‐induced hyperphagia. Our results suggest that peripheral obestatin is not a satiety signal that plays a role in the regulation of gastric emptying and do not support the concept that obestatin is a physiological opponent of ghrelin.
Glauberite–halite association of the Zaragoza Gypsum Formation (Lower Miocene, Ebro Basin, NE Spain)
Authors: SALVANY JOSEP M. , GARCÍA‐VEIGAS JAVIER , ORTÍ FEDERICO
Published: December 2006

Glauberite is the most common mineral in the ancient sodium sulphate deposits in the Mediterranean region, although its origin, primary or diagenetic, continues to be a matter of debate. A number of glauberite deposits of Oligocene–Miocene age in Spain display facies characteristics of sedimentologic significance, in particular those in which a glauberite–halite association is predominant. In this context, a log study of four boreholes in the Zaragoza Gypsum Formation (Lower Miocene, Ebro Basin, NE Spain) was carried out. Two glauberite–halite lithofacies associations, A and B, are distinguished: association (A) is composed of bedded cloudy halite and minor amounts of massive and clastic glauberite; association (B) is made up of laminated to thin‐bedded, clear macrocrystalline, massive, clastic and contorted lithofacies of glauberite, and small amounts of bedded cloudy halite. Transparent glauberite cemented by clear halite as well as normal‐graded and reverse‐graded glauberite textures are common. This type of transparent glauberite is interpreted as a primary, subaqueous precipitate. Gypsum, thenardite or mirabilite are absent in the two associations. The depositional environment is interpreted as a shallow perennial saline lake system, in which chloride brines (association A) and sulphate–(chloride) brines (association B) are developed. The geochemical study of halite crystals (bromine contents and fluid inclusion compositions) demonstrates that conditions for co‐precipitation of halite and glauberite, or for precipitation of Na‐sulphates (mirabilite, thenardite) were never fulfilled in the saline lake system.
The relationship between channel avulsion, flow occupancy and aggradation in braided rivers: insights from an experimental model
Authors: ASHWORTH PHILIP J. , BEST JAMES L. , JONES MERREN A.
Published: December 2006

Experimental modelling of an aggrading braided river has allowed investigation of the relationship between the frequency of channel avulsion (Af), the duration of time that the braidplain is occupied by flow, the spatial pattern of braidplain sedimentation and how these respond to a change in sediment supply (Ss). Model results demonstrate a strong, positive relationship between Ss and Af and that there is no downstream change in Af over the short braidplain distances (ca 100 m) modelled herein. Although Af is strongly dependent on Ss, the degree of channel switching does not influence the rate, or spatial pattern, of braidplain sedimentation. All experiments used a single, central input for water and sediment, and the channels occupied the centre of the alluvial basin for a longer period of time than the margins for all sediment supply rates and distances downstream. Despite this spatio‐temporal pattern in flow occupancy, braidplain sedimentation rates were nearly uniform both downstream and across the basin, and increased at approximately the same rate as increases in Ss. As a consequence, less frequent, and possibly short‐lived, flows at the margins of the braidplain deposited and preserved more sediment per unit time in comparison with the centre of the basin where flow occupancy was higher. An approximate order of magnitude change in sediment supply resulted in only a factor of two change in bed slope, probably due to both an increase in channelization and adjustment of the channel form that maintained sediment transport through the basin. This result suggests that linear diffusion models are unlikely to be applicable in landscape evolution models that possess aggrading multi‐thread rivers, which are capable of self‐adjustment in channel number and form.
Provenance of Jurassic accretionary complex: Mino terrane, inner zone of south‐west Japan – implications for palaeogeography of eastern Asia
Authors: JOO YOUNG JI , LEE YONG IL , HISADA KEN‐ICHIRO
Published: December 2006

Provenance and tectonic history of the Jurassic accretionary complex, Mino terrane, located in the Inner Zone of south‐west Japan, were studied using sandstone framework composition and mudrock geochemistry. Modal analysis of sandstones shows that the tectonic setting of the source area for the studied Mino terrane clastic rocks was uplifted basement, largely dominated by high‐grade metamorphic terrain composed of quartz and feldspar, especially plagioclase. The textural and mineralogical immaturity, extent of alkali and alkaline earth element leaching, low chemical index of alteration values and depleted rare earth element (REE) contents suggest rapid uplift and erosion within the source terrain and a relatively weak weathering intensity. Factor analysis revealed that grain‐size effects governed compositional heterogeneity in the studied sediments. Provenance of the sediments is interpreted as being plagioclase‐enriched felsic basement rock, such as granodiorite, within a continental margin and evolved arc tectonic setting rather than active volcanic arc. Lack of a contribution from active volcanic arcs may have resulted from the cessation of volcanism during the reorganization of the subducting plate system and/or erosion of arc volcanics and exposure of basement. Considering the previous studies on palaeogeography and palaeocurrent reconstruction, the north‐eastern part of the Yeongnam massif in the Korean Peninsula is interpreted as the most probable source area for the studied turbidites. The results of mixing calculation for Mino terrane sediments suggest that Precambrian leucocratic granite and the basement rock of the Cretaceous Gyeongsang Basin shed large amounts of sediments to the Mino trench, whilst Precambrian granitic gneiss and the Triassic pluton supplied lesser amounts. The results of this study reveal that, although active subduction–accretion processes were occurring, the Mino trench was bordered by continental basement rocks. This knowledge contributes to enhanced understanding of the Jurassic palaeogeography of the east Asia continental margin.
Life cycle abbreviation in the trematodeCoitocaecum parvum: can parasites adjust to variable conditions?
Authors: LAGRUE C. , POULIN R.
Published: December 2006

The complex life cycles of parasites are thought to have evolved from simple one‐host cycles by incorporating new hosts. Nevertheless, complex developmental routes present parasites with a sequence of highly unlikely transmission events in order to complete their life cycles. Some trematodes likeCoitocaecum parvumuse facultative life cycle abbreviation to counter the odds of trophic transmission to the definitive host. Parasites adopting life cycle truncation possess the ability to reproduce within their intermediate host, using progenesis, without the need to reach the definitive host. Usually, both abbreviated and normal life cycles are observed in the same population of parasites. Here, we demonstrate experimentally thatC. parvumcan modulate its development in its amphipod intermediate host and adopt either the abbreviated or the normal life cycle depending on current transmission opportunities or the degree of intra‐host competition among individual parasites. In the presence of cues from its predatory definitive host, the parasite is significantly less likely to adopt progenesis than in the absence of such cues. An intermediate response is obtained when the parasites are exposed to cues from non‐host predators. The adoption of progenesis is less likely, however, when two parasites share the resource‐limited intermediate host. These results show that parasites with complex developmental routes have transmission strategies and perception abilities that are more sophisticated than previously thought.
Washing of stored red blood cells by an autotransfusion device before transfusion
Authors: De Vroege R. , Wildevuur W. R. , Muradin J. A. G. , Graves D. , Van Oeveren W.
Published: December 2006

Background and Objectives  The use of an autotransfusion device to wash blood of the incision site is increasing. After washing, this blood is retransfused without side effects caused by activated plasma factors and cell release products. This procedure could be extended to washing of donor blood, which may be particularly useful for red blood cells (RBCs) stored for more than 4 weeks that contain high concentrations of free haemoglobin, potassium, lactate and other metabolites. It is not known whether stored RBCs can withstand the cell washing procedure with the use of an autotransfusion device, while keeping their primary functions intact. The objective of this study was to determine the quality of RBCs, after cell washing in comparison to untreated RBCs.

Materials and Methods  RBCs were studied in terms of integrity (free haemoglobin), stored energy (2,3‐diphosphoglycerate, adenosine triphosphate), metabolites (lactate, potassium) and physical characteristics (osmotic resistance, aggregability, deformability).

Results  After washing, free lactate and potassium were significantly reduced as compared to the levels before washing. The osmotic resistance of RBCs slightly improved, whereas aggregation capacity reduced after washing. Fifteen per cent of haemoglobin was lost during washing. The deformability and free haemoglobin levels remained unchanged.

Conclusion  Washing stored blood before transfusion may be of benefit, because the waste products are effectively removed from the stored RBC.
FY*X real‐time polymerase chain reaction with melting curve analysis associated with a complete one‐step real‐time FY genotyping
Authors: Ansart‐Pirenne H. , Martin‐Blanc S. , Le Pennec P.‐Y. , Rouger P. , Cartron J.‐P. , Tournamille C.
Published: December 2006

Background and Objectives  The Duffy (FY) blood group system is controlled by four major alleles: FY*A and FY*B, the Caucasian common alleles, encoding Fya and Fyb antigens; FY*X allele responsible for a poorly expressed Fyb antigen, and FY*Fy a silent predominant allele among Black population. Despite the recent development of a real‐time fluorescent polymerase chain reaction (PCR) method for FY genotyping FY*X genotyping has not been described by this method. This study focused on the real‐time FY*X genotyping development associated with a complete, one‐step real‐time FY genotyping, based on fluorescence resonance energy transfer (FRET) technology.

Materials and Methods  Seventy‐two blood samples from Fy(a+b–) Caucasian blood donors were studied by real‐time PCR only. Forty‐seven Caucasian and Black individual blood samples, referred to our laboratory, were studied by PCR‐RFLP and real‐time PCR. For each individual, the result of the genotype was compared to the known phenotype.

Results  The FY*X allele frequency calculated in an Fy(a+b–) Caucasian blood donors population was 0·014. With the Caucasian and Black patient samples we found a complete correlation between PCR‐RFLP and the real‐time PCR method whatever the alleles combination tested. When the known phenotype was not correlated to FY*X genotype, the presence of the Fyb antigen was always confirmed by adsorption–elution.

Conclusion  The real‐time technology method is rapid and accurate for FY genotyping. From now, we are able to detect the FY*X allele in all the alleles combinations studied. Regarding its significant frequency, the detection of the FY*X allele is useful for the correct typing of blood donors and recipients considering the therapeutic use of blood units and the preparation of test red blood cells for antibody screening.
Longitudinal magnetic resonance imaging study of rhesus monkey brain development
Authors: Malkova L. , Heuer E. , Saunders R. C.
Published: December 2006

To examine early brain development, T1‐weighted structural MRI scans of seven rhesus monkeys (Macaca mulatta) were obtained longitudinally between the ages of 1 week and 4 years at 12 age points. Total brain volume, calculated at each age point, increased significantly, by 56%, between 1 week and 4 years. The greatest increase of 22% occurred between 1 week and 1 month, followed by further significant increases between 1 and 2 months, and 3 and 4 months. Gradually smaller increases continued up to 3 years with no further significant changes thereafter. A robust maturation of white matter occurred between 1 week, at which the only easily identifiable fibre tracts were internal capsule and optic radiations, and 3 months, at which most large fibre tracts were visible; only at this age reproducible measurements were possible for all cases. White matter volume increased by 126% between 3 months and 4 years, with the biggest increase between 3 and 4 months (32%) followed by smaller but significant increases up to 4 years. The macaque brain development parallels that of humans by reaching the maximum in total brain volume around the age of sexual maturity (in macaques 3–4 years) and by the increases in white matter continuing beyond this age. The most rapid growth in both total brain volume and white matter from birth to approximately 4 months is consistent with the emergence of various cognitive abilities in macaques at that age.