bluuebunny/crossref_metadata_2025 huggingface dataset:
Courtship behaviour in the sandfly Lutzomyia longipalpis, the New World vector of visceral leishmaniasis
Authors: BRAY D. P. , HAMILTON J. G. C.
Published: September 2010

Abstract Courtship behaviour in Lutzomyia longipalpis Lutz and Neiva (Diptera: Psychodidae) was examined to determine the sequence of behaviours that occur prior to copulation. Courtship consisted of a series of male and female touching and wing‐flapping behaviours, with males performing a greater variety of wing‐flapping behaviours than previously described. Occurrence of male approach‐flapping, semi‐circling and female stationary‐flapping were all predictors of eventual copulation, and may coincide with the dispersal of pheromones or the production of auditory signals important to courtship. Touching occurred in the majority of observations, with contact most often made with the tips of the legs and antennae. This behaviour, not previously described in sandflies, was initiated by males and females, and may indicate the use of contact pheromones, a form of communication previously overlooked in L. longipalpis. Future studies are required to separate the auditory and chemical signals associated with wing‐flapping, and to confirm whether L. longipalpis possesses cuticular hydrocarbons capable of inducing behavioural responses. The identification of signals that inhibit sexual behaviour during courtship may be particularly relevant to developing mating disruption techniques against L. longipalpis.
Population dynamics of pest mosquitoes and potential malaria and West Nile virus vectors in relation to climatic factors and human activities in the Camargue, France
Authors: PONÇON N. , TOTY C. , L’AMBERT G. , LE GOFF G. , BRENGUES C. , SCHAFFNER F. , FONTENILLE D.
Published: September 2010

Abstract The Camargue is an extensive wetland in the southeast of France, which is highly influenced by human activities. Large ponds, marshes and irrigated fields provide abundant potential breeding sites for mosquitoes. mosquitoes, which are important in terms of the nuisance they cause to people and animals, the limitations they impose on tourism and their potential threat to human health. Several of the mosquito species present are potential vectors of malaria and West Nile virus. Therefore, the population dynamics of these species were monitored over an entire breeding season during March–October 2005. Mosquito populations were sampled in two study areas once every 2 weeks, using CDC light traps baited with CO2. Sixteen species were collected. The majority (98.7%) of the catch were Aedes caspius (Pallas) (Diptera: Culicidae), Culex modestus (Ficalbi), Culex pipiens L. and Anopheles hyrcanus (Pallas). The population dynamics of these species varied considerably in relation to the species’ biology, climatic conditions (rainfall, temperature and season), water management, implementation of mosquito control campaigns and landscape use.
Abundance, biting behaviour and parous rate of anopheline mosquito species in relation to malaria incidence in gold‐mining areas of southern Venezuela
Authors: MORENO J. E. , RUBIO‐PALIS Y. , PÁEZ E. , PÉREZ E. , SÁNCHEZ V.
Published: September 2010

Abstract A longitudinal entomological and epidemiological study was conducted in five localities of southern Venezuela between January 1999 and April 2000 to determine the abundance, biting behaviour and parity of anopheline mosquitoes (Diptera: Culicidae) in relation to climate variables and malaria incidence. A total of 3685 female anopheline mosquitoes, representing six species, were collected. The most abundant species were Anopheles marajoara Galvão & Damasceno (60.7%) and Anopheles darlingi Root (35.1%), which together represented 95.8% of the total anophelines collected. Abundance and species distribution varied by locality. Malaria prevalence varied from 12.5 to 21.4 cases per 1000 population. Transmission occurred throughout the year; the annual parasite index (API) for the study period was 813.0 cases per 1000 population, with a range of 71.6−2492 per 1000 population, depending on locality. Plasmodium vivax (Grassi & Feletti) (Coccidia: Plasmodiidae) accounted for 78.6% of cases, Plasmodium falciparum (Welch) for 21.4% and mixed infections (Pv+Pf) for < 0.1%. Anopheles marajoara and An. darlingi were more abundant during the rainy season (April–September). There was no significant correlation (P > 0.05) between mosquito abundance and rainfall. Correlations between malaria incidence by parasite species and mosquito abundance were not significant (P > 0.05). Monthly parous rates were similar for An. marajoara and An. darlingi throughout the year, with two peaks that coincided with the dry−rainy transition period and the period of less rain. Peaks in the incidence of malaria cases were observed 1 month after major peaks in biting rates of parous anophelines. Anopheles darlingi engages in biting activity throughout the night, with two minor peaks at 23.00–00.00 hours and 03.00–04.00 hours. Anopheles marajoara has a different pattern, with a biting peak at 19.00−21.00 hours and 76.6% of biting occurring before midnight. Although both vectors bite indoors and outdoors, they showed a highly significant (P < 0.01) degree of exophagic behaviour. The present study constitutes the first effort to characterize the bionomics of anophelines in malaria endemic foci in different ecological situations in relation to malaria transmission in southern Venezuela and to provide relevant information to be considered when planning and implementing vector control programmes.
Recent volcanism and mitochondrial DNA structuring in the lizard Gallotia atlantica from the island of Lanzarote
Authors: BLOOR P. , KEMP S. J. , BROWN R. P.
Published: September 2010

The phylogeography of the lacertid lizard Gallotia atlantica from the small volcanic island of Lanzarote (Canary Islands) was analysed based on 1075 bp of mitochondrial DNA (mtDNA) sequence (partial cytochrome b and ND2) for 157 individuals from 27 sites (including three sites from neighbouring islets). Levels of sequence divergence were generally low, with the most distant haplotypes separated by only 14 mutational steps. MtDNA divergence appears to coincide with formation of the middle Pleistocene lowland that united formerly separate ancient islands to form the current island of Lanzarote, allowing rejection of a two‐island model of phylogeographical structure. There was evidence of large‐scale population expansion after island unification, consistent with the colonization of new areas. A nested clade phylogeographical analysis (NCPA) revealed significant phylogeographical structuring. Two‐step and higher‐level clades each had disjunct distributions, being found to the east and west of a common area with a north–south orientation that extends between coasts in the centre‐east of the island (El Jable). Other clades were almost entirely restricted to the El Jable region alone. Bayesian Markov chain Monte Carlo analyses were used to separate ongoing gene flow from historical associations. These supported the NCPA by indicating recent (75 000–150 000 years ago) east–west vicariance across the El Jable region. Lava flows covered El Jable and other parts of the central lowland at this time and likely led to population extinctions and temporary dispersal barriers, although present‐day evidence suggests some populations would have survived in small refugia. Expansion of the latter appears to explain the presence of a clade located between the eastern and western components of the disjunct clades. Direct relationships between mtDNA lineages and morphology were not found, although one of two morphological forms on the island has a disjunct distribution that is broadly concordant with east–west components of the phylogeographical pattern. This work demonstrates how recent volcanic activity can cause population fragmentation and thus shape genetic diversity on microgeographical scales.
Selection on domestication traits and quantitative trait loci in crop–wild sunflower hybrids
Authors: BAACK ERIC J. , SAPIR YUVAL , CHAPMAN MARK A. , BURKE JOHN M. , RIESEBERG LOREN H.
Published: September 2010

The strength and extent of gene flow from crops into wild populations depends, in part, on the fitness of the crop alleles, as well as that of alleles at linked loci. Interest in crop–wild gene flow has increased with the advent of transgenic plants, but nontransgenic crop–wild hybrids can provide case studies to understand the factors influencing introgression, provided that the genetic architecture and the fitness effects of loci are known. This study used recombinant inbred lines (RILs) generated from a cross between crop and wild sunflowers to assess selection on domestication traits and quantitative trait loci (QTL) in two contrasting environments, in Indiana and Nebraska, USA. Only a small fraction of plants (9%) produced seed in Nebraska, due to adverse weather conditions, while the majority of plants (79%) in Indiana reproduced. Phenotypic selection analysis found that a mixture of crop and wild traits were favoured in Indiana (i.e. had significant selection gradients), including larger leaves, increased floral longevity, larger disk diameter, reduced ray flower size and smaller achene (seed) mass. Selection favouring early flowering was detected in Nebraska. QTLs for fitness were found at the end of linkage groups six (LG6) and nine (LG9) in both field sites, each explaining 11–12% of the total variation. Crop alleles were favoured on LG9, but wild alleles were favoured on LG6. QTLs for numerous domestication traits overlapped with the fitness QTLs, including flowering date, achene mass, head number, and disk diameter. It remains to be seen if these QTL clusters are the product of multiple linked genes, or individual genes with pleiotropic effects. These results indicate that crop trait values and alleles may sometimes be favoured in a noncrop environment and across broad geographical regions.
Contrasting demographic history and phylogeographical patterns in two Indo‐Pacific gastropods
Authors: CRANDALL ERIC D. , FREY MELISSA A. , GROSBERG RICHARD K. , BARBER PAUL H.
Published: September 2010

Marine species with ranges that span the Indo‐Australian Archipelago (IAA) exhibit a range of phylogeographical patterns, most of which are interpreted in the context of vicariance between Indian and Pacific Ocean populations during Pliocene and Pleistocene low sea‐level stands. However, patterns often vary among ecologically similar taxa, sometimes even within genera. This study compares phylogeographical patterns in two species of highly dispersive neritid gastropod, Nerita albicilla and Nerita plicata, with nearly sympatric ranges that span the Indo‐Pacific. Mitochondrial COI sequences from > 1000 individuals from 97 sites reveal similar phylogenies in both species (two divergent clades differing by 3.2% and 2.3%, for N. albicilla and N. plicata, respectively). However, despite ecological similarity and congeneric status, the two species exhibit phylogeographical discordance. N. albicilla has maintained reciprocal monophyly of Indian and Pacific Ocean populations, while N. plicata is panmictic between oceans, but displays a genetic cline in the Central Pacific. Although this difference might be explained by qualitatively different demographic histories, parameter estimates from three coalescent models indicate that both species have high levels of gene flow between demes (2Nem > 75), and share a common history of population expansion that is likely associated with cyclical flooding of continental shelves and island lagoons following low sea‐level stands. Results indicate that ecologically similar, codistributed species may respond very differently to shared environmental processes, suggesting that relatively minor differences in traits such as pelagic larval duration or microhabitat association may profoundly impact phylogeographical structure.
Variation in symbiont distribution between closely related coral species over large depth ranges
Authors: FRADE P. R. , DE JONGH F. , VERMEULEN F. , VAN BLEIJSWIJK J. , BAK R. P. M.
Published: September 2010

Symbiotic algae in coral species distributed over a large depth range are confronted with major differences in light conditions. We studied the genetic variation of Symbiodinium in the coral genus Madracis over depth (5–40 m) and at two different colony surface positions. Using polymerase chain reaction–denaturing gradient gel electrophoresis ITS2 nuclear ribosomal DNA analyses, we consistently identified three symbiont genotypes with distributions that reveal patterns of host specificity and depth‐based zonation. ITS2 type B7 Symbiodinium is the generalist type, occurring in all zooxanthellate Madracis corals and at all depths. Type B13 is restricted to the shallow water specialist Madracis mirabilis. Type B15 is typical of deep reef environments and replaces B7 in the depth generalist Madracis pharensis. Contrasting with variation over depth, we found strong functional within‐colony uniformity in symbiont diversity. Relating symbiont distributions to measured physical factors (irradiance, light spectral distribution, temperature), suggests depth‐based ecological function and host specificity for Symbiodinium ITS2 types, even among closely related coral species.
Human antibody responses to Pfs 230, a sexual stage‐specific surface antigen of Plasmodium falciparum: non‐responsiveness is a stable phenotype but does not appear to be genetically regulated
Authors: RILEY E. M. , BENNETT S. , JEPSON A. , HASSAN‐KING M. , WHITTLE H. , OLERUP O. , CARTER R.
Published: September 2010

The 230 kD gamete surface protein of the malaria parasite Plasmodium falciparum (Pfs 230) is a target of transmission blocking antibodies. Anti‐Pfs 230 antibodies are induced following natural infection with malaria but are not found in all P. falciparum‐exposed individuals. In this study we have shown that approximately 40% of malaria‐exposed Gambians do not make antibodies to the native Pfs 230 molecule. This phenotype is remarkably stable over time and does not appear to be related to age, malaria exposure or major histocompatibility complex genotype. Comparison of antibody responses in twins indicates that the anti‐Pfs 230 response is not strictly genetically controlled, but a high degree of concordance within both dizygous and monozygous twin pairs suggests that factors associated with exposure to malaria in childhood may be important in determining the subsequent immune response.
Trypanosoma cruzi infection in mice induces a polyisotypic hypergammaglobulinaemia and parasite‐specific response involving high lgG2a concentrations and highly avid lgG1 antibodies
Authors: BOUHDIDI AYACHI EL , TRUYENS CARINE , RIVERA MARIA‐TERESA , BAZIN HERVÉ , CARLIER1 YVES
Published: September 2010

Trypanosoma cruzi infection in BALB/c mice induced a reversible polyisotypic hypergammaglobulinaemia, with particularly high levels of IgG2a, IgM and IgE. Hypergammaglobulinaemia started during the acute phase of infection and persisted during chronic disease until 11–13 weeks post‐infection (w.p.i.), when immunoglobulin levels, with the exception of IgE, returned near normal values. Parasite‐specific antibodies counted for 14 to 23% of gammaglobulinaemia, in acute and chronic infection respectively. The titres of IgM antibodies rose from two w.p.i. IgA, IgE and IgG subclass antibodies built up gradually over the time of parasite clearance (i.e., between three and six w.p.i.). All antibody isotypes, including IgM reached significant and stable titres throughout chronic infection. IgG2a, IgG1 and IgM antibodies had constantly higher titres than the other antibody isotypes. The dominance of IgG2a antibodies was due to their high plasma concentrations, around 70% of all antibodies available in the chronic infection. IgG1 had the highest functional avidity, whereas its concentration corresponded to only 10% of the whole antibody fraction. These results indicate that T. cruzi infection in mice induces a polyisotypic humoral immune response, dominated by some antibody isotypes, with major differences in concentrations and functional avidities. This could be of crucial importance in determining the outcome of infection.
Theileria annulata sporozoite surface antigen (SPAG‐1) contains neutralizing determinants in the C terminus
Authors: BOULTER NICKY , KNIGHT PAMELA A. , HUNT PHILIP D. , HENNESSEY EMMA S. , KATZER FRANK , TAIT ANDREW , WILLIAMSON SUSANNA , BROWN DUNCAN , BAYLIS HOWARD A. , HALL ROGER
Published: September 2010

SPAG‐1 is a surface antigen on Theileria annulata sporozoites that is a candidate both for inclusion in a subunit vaccine and as a ligand for host cell recognition. We have pinpointed major neutralizing epitopes to the C terminus. To facilitate this we expressed SPAG‐1 as a series of defined fragments in the pGEX system. These constructs were validated by sequencing and by their spectrum of reactivity with monoclonal antibody (MoAb) BA4. This MoAb recognizes the elastin motif VGVAPG, that is predicted to occur three times in the N terminal half of SPAG‐1. The recombinant proteins were then tested by Western blotting with a neutralizing MoAb (1A7) and two neutralizing bovine sera (10T and 34A). The results demonstrate that 1A7 and the bovine sera react with determinants unique to the C terminus. We mapped the neutralizing determinant recognized by MoAb 1A7 to a 16 residue sequence (residues 807–822) using synthetic peptides. Interestingly the bovine sera do not recognize the 1A7 epitope. The potential role of the C terminus as a ligand for host cell recognition and the implications for sub‐unit vaccine production are discussed.
Lymphocyte proliferation and cytokine production in mice infected with different geographical isolates of Trichinella spiralis
Authors: GOYAL P. K. , HEŘMÁNEK J. , WAKELIN D.
Published: September 2010

Antigen‐specific proliferative responses and cytokine production were measured in lymphocytes taken from inbred NIH mice infected with different isolates of Trichinella spiralis. Stimulation with muscle larval homogenate antigen produced high proliferative responses, cells responding more strongly to antigen from one isolate (London‐L) than to antigens of the other two isolates (Spanish‐S and Polish‐P). Antigen from the P‐isolate elicited relatively poor responses. There was considerable, although variable, cross reactivity between isolate antigens and this was reflected in proliferation to heterologous stimulation. When pulsed with the mitogen Concanavalin A (Con‐A) mesenteric lymph node cells (MLNC) produced IFN‐gamma on day four post infection but not on day eight. In contrast, production of IL‐4 and IL‐5 was greatest on day eight. Differences were seen in levels of cytokine production between cells taken from mice infected with different isolates. These data show a sequential activation of Th1 and Th2 cells during infection with T. spiralis isolates, and suggest that the level of activation of each Th subset is influenced by the antigenic characteristics of each isolate.
BCG–malaria co‐Infection has paradoxical effects on C57BL/6 and A/J mouse strains
Authors: LEISEWITZ A.L. , ROCKETT K. , KWIATKOWSKI D.
Published: September 2010

Bacillus Calmette‐Guérin (BCG) infection of the spleen is a potent modifier of splenic function. Prior to malaria infection, we infected two mouse strains of differing susceptibility to Plasmodium chabaudi AS (C57BL/6 and A/J) with this mycobacterium. We then evaluated aspects of spleen cell composition, architecture and cytokine expression, and correlated these with the outcome. BCG preinfection resulted in protection of the A/J mice but paradoxically resulted in mortality of the C57BL/6 mice. The latter developed higher parasitaemias that peaked earlier than the A/J mice rendered resistant by BCG. BCG infection induced remarkable changes to splenic histology examined by H&E staining, but there were no consistent differences between mouse strains. C57BL/6 mice had higher absolute numbers of all immune cell phenotypes than did A/J mice, and higher macrophage and dendritic cell proportions. BCG‐induced resistance in A/J mice was associated with an increased CD4+ expression of IFN‐γ whilst induced death in C57BL/6 mice was associated with excessive IFN‐γ expression. A moderate TH1 response in the A/J model may have been responsible for the improved survival, and an excessive TH1 response in the C57BL/6 model may have contributed to their death.
Identification of a 55 kDa Haemonchus contortus excretory/secretory glycoprotein as a neutrophil inhibitory factor
Authors: ANBU K. A. , JOSHI P.
Published: September 2010

Haemonchus contortus is an economically important gastric parasite infecting sheep and goats. The parasite survives the host immune attack by releasing protective molecules. In the present study, a 55 kDa secretory glycoprotein (gp55) was identified that inhibited host neutrophils as judged by reduced H2O2 production by these cells. The binding of gp55 to neutrophils was confirmed by flow cytometry. This binding was mediated by cellular CD11b/CD18 integrin. The glycoprotein gp55 also bound to goat monocytes and lymphocytes and inhibited monocyte function. Using light fluorescence microscopy, gp55 was localized at the surface of adult worms. The absence of gp55 in the infective L3 larvae and its expression in the blood‐feeding stage support a role for gp55 in the parasitic stage of the organism.
Regulation of toll‐like receptors in intestinal epithelial cells by stress and Toxoplasma gondii infection
Authors: GOPAL R. , BIRDSELL D. , MONROY F. P.
Published: September 2010

Intestinal epithelial cells (IECs) form a barrier between invading microorganisms and the underlying host tissues. IECs express toll‐like receptors (TLRs) that recognize specific molecular signatures on microbes, which activate intracellular signalling pathways leading to production of proinflammatory cytokines and chemokines. Stress hormones play an important role in modulation of proinflammatory cytokines and down‐regulation of immune responses. Here we demonstrated that expression levels of TLR‐2, TLR‐4, TLR‐9 and TLR‐11 were significantly increased in mouse IECs following infection with Toxoplasma gondii on day 8 postinfection. In contrast, expression of TLRs was significantly decreased in infected mice subjected to cold water stress (CWS + INF). Expression of TLR‐9 and TLR‐11 in the mouse MODE‐K cell line was significantly increased after infection. Expression of TLR‐9 and TLR‐11 in cells exposed to norepinephrine (NE) and parasites was significantly decreased when compared to cells exposed to parasites only. A significant increase was observed in SIGIRR, a negative regulator of TLRs in the CWS + INF group when compared to the INF group. Stress components were able to decrease expression levels of TLRs in IECs, decrease parasite load, and increase expression of a negative regulator thereby ameliorating intestinal inflammatory responses commonly observed during per oral T. gondii infection in C57BL/6 mice.
Depletion of stromal Pi induces high ‘energy‐dependent’ antenna exciton quenching (qE) by decreasing proton conductivity at CFO‐CF1 ATP synthase
Authors: TAKIZAWA KENJI , KANAZAWA ATSUKO , KRAMER DAVID M.
Published: September 2010

This work tests two models to account for the effects of depletion of stromal inorganic phosphate (Pi), which results in down‐regulation of light capture via the exciton quenching (qE) mechanism and has been proposed to act in feedback regulation of the light reactions. In both models, antenna down‐regulation is activated by acidification of the lumen, despite the fact that linear electron flow (LEF) (and associated proton flux) is decreased upon Pi depletion. In one model, an imbalance of ATP or NADPH activates cyclic electron transfer around photosystem I (CEF1), increasing proton influx to the lumen. In the second, the effective conductivity of the CFO‐CF1 ATP synthase to protons (gH+) is decreased, retarding proton efflux from the lumen. Sequestering of Pi by mannose infiltration increased sensitivities of qE and pmf to LEF. The effects were attributable to decreases in gH+, but not to CEF1 and were largely reversed by subsequent Pi feeding. Rapid recovery of gH+ in the dark suggested that dark‐labile metabolic pools are responsible for regulation of the ATP synthase. Overall, these results support models where accumulation of Benson–Calvin cycle intermediates or lowering of stromal Pi below its KMat the ATP synthase, retards proton efflux from the lumen, leading to build‐up of pmf and subsequent down‐regulation of photosynthetic light capture.
Regulation of isoprene emission in Populus trichocarpa leaves subjected to changing growth temperature
Authors: WIBERLEY AMY E. , DONOHUE AUTUMN R. , MEIER MARY E. , WESTPHAL MAIKEN M. , SHARKEY THOMAS D.
Published: September 2010

The hydrocarbon isoprene is emitted in large quantities from numerous plant species, and has a substantial impact on atmospheric chemistry. Temperature affects isoprene emission at several levels: the temperature at which emission is measured, the temperature at which leaves develop, and the temperatures to which a mature leaf is exposed in the days prior to emission measurement. The molecular regulation of the response to the last of these factors was investigated in this study. When plants were grown at 20 °C and moved from 20 to 30 °C and back, or grown at 30 °C and moved from 30 to 20 °C and back, their isoprene emission peaked within 3 h of the move and stabilized over the following 3 d. Trees that developed at 20 °C and experienced 30 °C episodes had higher isoprene emission capacities than did leaves grown exclusively at 20 °C, even 2 weeks after the last 30 °C episode. The levels and extractable activities of isoprene synthase protein, which catalyses the synthesis of isoprene, and those of dimethylallyl diphosphate (DMADP), its substrate, alone could not explain observed variations in isoprene emission. Therefore, we conclude that control of isoprene emission in mature leaves is shared between isoprene synthase protein and DMADP supply.
Exploring genetic and expression differences between physiologically extreme ecotypes: comparative genomic hybridization and gene expression studies of Kas‐1 and Tsu‐1 accessions of Arabidopsis thaliana
Authors: JUENGER THOMAS E. , SEN SAUNAK , BRAY ELIZABETH , STAHL ELI , WAYNE TIERNEY , MCKAY JOHN , RICHARDS JAMES H.
Published: September 2010

Recent studies have documented remarkable genetic variation among Arabidopsis thaliana accessions collected from diverse habitats. Of particular interest are accessions with putatively locally adapted phenotypes – that is, accessions with attributes that are likely adaptive at their sites of origin. These genotypes may provide insight into the genetic basis of adaptive evolution as well as allow the discovery of genes of ecological importance. We studied the physiology, genome content and gene expression of two physiologically extreme accessions (Tsu‐1 from Tsushima, Japan and Kas‐1 from Kashmir, India). Our study was conducted under two levels of soil moisture and accompanied by physiological measurements to characterize early responses to soil drying. Genomic hybridizations identified 42 503 single feature polymorphisms (SFP) between accessions, providing an initial screen for genetic differences. Transcript profiling identified a large number (5996) of genes exhibiting constitutive differences in expression including genes involved in many biological pathways. Mild soil drying resulted in only subtle physiological responses but resulted in gene expression changes in hundreds of transcripts, including 352 genes exhibiting differential responses between accessions. Our results highlight the value of genomic studies of natural accessions as well as identify a number of candidate genes underlying physiological differences between Tsu‐1 and Kas‐1.
Lettuce mosaic virus
Authors: DINANT S. , LOT H.
Published: September 2010

Lettuce mosaic virus (LMV) is an economically significant virus of lettuce and endive. The virus has spread world‐wide due to the exchange of seed of lettuce varieties. A very high proportion of infected plants may result from a low level of infected seed, because of very efficient transmission by a number of aphid species. The symptoms are characteristic but the diagnosis can be difficult, particularly on lettuce, because numerous viruses may coinfect this species. A very reliable and sensitive method by ELISA has been established for diagnosis and detection, which gives a good estimation ofthe contamination level in a seed batch. The use of virus‐free seed, preventive cultural practices and the use of tolerant varieties were shown to be good methods for control if rigorously applied. Up to now, strains able to overcome the genes g and mo, considered to be identical, were shown to be non‐seed‐transmissible. Studies carried out with several virulent isolates have shown that genes mo and g are different and probably allelic, and that one strain infects seed at a very high level on susceptible and tolerant genotypes. These features have necessitated the production of virus‐free seed, including systematic checks on all cultivars, and have stimulated research on new sources of resistance. Recent molecular studies have provided clones for detection and strain differentiation. Assays to introduce different LMV genes into lettuce seem promising.
The classification of isolates of Gaeumannomyces graminis from wheat, rye and oats using restriction fragment length polymorphisms in families of repeated DNA sequences
Authors: ODELL M. , FLAVELL R. B. , HOLLINS T. W.
Published: September 2010

Isolates of the take‐all fungus, Gaeumannomyces graminis var. avenae, which affects oats, wheat and other grasses, and of G.g. var. tritici, which preferentially affects wheat, rye and barley, contain a high proportion of repeated sequences. Total DNA from 57 fungal isolates collected from many locations and different cereal hosts, and scored for virulence on wheat, rye and oats, revealed many restriction fragment length polymorphisms. These RFLPs were observed either by staining the DNA directly, by hybridization to radioactively labelled total fungal DNA, or by hybridization with labelled wheat ribosomal DNA. With only a few exceptions, the isolates with the same preferred cereal hosts showed more similar patterns of restriction fragments than isolates that had different pathogenicity properties on cereal hosts, irrespective of the geographical origins of the isolates. This was even the case for R isolates of G.g. var. tritici that were virulent on wheat and rye compared with N isolates that were virulent only on wheat. Isolates were identified by hybridizing DNA from infected root samples with 32P‐labelled total fungal DNA. The restriction fragment polymorphisms involving families of repeated sequence can therefore be used as a predictive assay for host preference of an isolate, and have probably arisen by host selection of fungal lineages. The variation between isolates in different pathogenicity groups suggests that there is little gene flow between isolates that can infect different hosts, even though they can coexist in the same field.
Cyclopaldic acid, a major phytotoxic metabolite of Seiridium cupressi, the pathogen of a canker disease of cypress
Authors: GRANITI A. , SPARAPANO L. , EVIDENTE A.
Published: September 2010

A phytotoxic substance was produced in vitro in a relatively high concentration (c. 40 mg/1) by Seiridium cupressi, a fungus that causes a canker disease of cypress (Cupressus sempervirens) and other Cupressaceae in Greece and in other parts of the world. Structural investigations demonstrated that the substance was identical with cyclopaldic acid, an antibiotic known to be a metabolite of some species of Penicillium, Aspergillus and Pestalotiopsis. Absorbed by severed twigs of three species of Cupressus and by cuttings of two herbaceous non‐host plants (tomato and mung bean), cyclopaldic acid at concentrations of 10‐100 ug/ml induced leaf chlorosis and necrosis. Oat seed germination and root growth of oat seedlings were also reduced to about 50% at 75 and 100 jig/ml, respectively. The compound showed antifungal activity towards species of Botrytis. Fusarium and Geotrichum when assayed at a concentration range from 10 to 100 /ug ml. We believe this to be the first report of cyclopaldic acid as a non‐selective fungal phytotoxin. However, its possible role in the pathogenesis of the cypress canker disease has not been established.
Modelling of cyclic tidal rhythmites (Carboniferous of Indiana and Kansas, Precambrian of Utah, USA) as a basis for reconstruction of intertidal positioning and palaeotidal regimes
Authors: ARCHER ALLEN W. , JOHNSON TROY W.
Published: September 2010

Analyses are presented for a variety of ancient cyclic tidal rhythmites, which exhibit well developed neap‐spring tidal periods. Many such rhythmites were formed within the upper intertidal zone and exhibit truncated cycles that contain relatively few discrete lamina per neap‐spring cycle. In such cases it can be difficult to determine if the originated palaeotidal system was diurnal or semidiurnal.

Based on sedimentological controls observed in modern analogues, the development of cyclic tidal rhythmites can be modelled by use of predicted tidal‐height information. The modelling used a 19‐year‐long series of tidal heights, which were subsequently used to approximate tidal velocities and rhythmite sedimentation. Modelling was based on a range of diurnal to semidiurnal regimes and comparisons were performed at a number of levels within the intertidal zone. This modelling produced a long series of simulated laminae‐thickness series which could be cross‐correlated with ancient laminae‐thickness series measured directly from ancient rhythmites.

This approach involved 1.6 × 106 comparisons of each ancient rhythmite series to the series simulated from the predictive tidal‐height information. The high correlations derived for such comparisons indicate that reasonable approximations to the palaeotidal systems can be made. In some cases, it is possible to determine the diurnal or semidiurnal nature of the originating palaeotidal system.
Bed thickness characteristics of inner‐shelf storm deposits associated with a transgressive to regressive Holocene wave‐dominated shelf, Sendai coastal plain, Japan
Authors: TAMURA TORU , MASUDA FUJIO
Published: September 2010

Holocene inner‐shelf storm deposits preserved beneath the Sendai coastal plain facing the Pacific coast of north‐eastern Japan were formed during a transgressive–regressive cycle. The evolution of the Holocene wave‐dominated depositional system along the Sendai coast is reconstructed using 76 AMS (accelerator mass spectrometers) 14C ages and the origin of bed thickness variations in the inner‐shelf storm deposits is explored. The Holocene succession is <30 m thick and overlies latest Pleistocene to early Holocene non‐marine deposits above a transgressive ravinement surface. It comprises transgressive ravinement and inner‐shelf deposits, and regressive inner shelf, shoreface, and coastal plain deposits. The inner‐shelf deposits comprise alternating sand and mud layers interpreted as stacked storm beds. The average preservation interval of a single storm bed is shortest during the transgression (5·7–20·6 years), and then increases to a maximum during the early regression (83·3–250·0 years), decreasing to 7·7–31·3 years with shoreline progradation. Average accumulation rates decreased during the transgression and then increased during the regression, but the sand/mud ratio varies little, reflecting inefficient sediment segregation downdip on the inner shelf. The vertical pattern of sand‐layer thicknesses also shows no relationship to position within the cycle, although small‐scale intervals of upward thickening and thinning probably relate to lateral switching of river mouths and/or random storm processes. The average thickness of storm beds is the highest in the interval deposited during the period from maximum flooding to early regression. This is probably because of the low preservation potential of thin beds associated with frequent, low‐magnitude storms during this period of low accumulation rates and extensive reworking. This preservation bias and the nature of the Sendai inner shelf resulted in an absence of characteristic bed thickness trends in the preserved storm deposits.
Molar tooth structures of the Neoarchean Monteville Formation, Transvaal Supergroup, South Africa. II: A wave‐induced fluid flow model
Authors: BISHOP JAMES W. , SUMNER DAWN Y. , HUERTA NICOLAS J.
Published: September 2010

Sedimentological, morphological, and geochemical characteristics of molar tooth (MT) structures in the ca 2·6 Ga Monteville Formation suggest a new fluid flow model for MT formation: (i) intercalated shales and carbonate sands were deposited near to above storm wave base; (ii) sediments cracked, forming an interconnected network of MT cracks that were also open to pores in sand lenses; (iii) storm waves pumped sea water into open MT crack networks, causing rapid microcrystalline carbonate nucleation, Ostwald ripening of nuclei, and growth of granular carbonate cores; some of these cores were transported by water flowing through the cracks; (iv) unfilled MT cracks collapsed, and filled MT ribbons deformed plastically as host sediments compacted and dewatered; (v) carbonate cores were overgrown by polygonal rims; and (vi) MT structures deformed brittlely with additional compaction and produced pebbly lags if reworked. MT cracks may have formed by multiple mechanisms; however, expansion of gas from organic decay and sediment heaving due to wave loading best explain MT crack morphology and are most consistent with the fluid flow model for MT CaCO3 presented here.
Molecular phylogeny of Anthelidae and other bombycoid taxa (Lepidoptera: Bombycoidea)
Authors: ZWICK ANDREAS
Published: September 2010

Abstract Based on DNA sequences of the fusion protein carbamoylphosphate synthetase/aspartate transcarbamylase/dihydroorotase (CAD; 680 bp) and elongation factor‐1α (Ef‐1α; 1240 bp); the first molecular phylogeny of the moth family Anthelidae and its placement within the Bombycoidea sensu Brock (1971) (= bombycoid complex sensu Minet, 1994) is proposed. The results strongly support the monophyly of the family Anthelidae and its subfamilies Munychryiinae and Anthelinae, but demonstrate the vast polyphyly of its main genus Anthela Walker, 1855. The proposed phylogeny suggests that grass feeding, as apparent from some pest records, probably is an ancestral trait within the subfamily Anthelinae. Evolutionary relationships of the family Anthelidae and of most parts of the Bombycoidea remain obscure. However, the results contradict many of the widely accepted phylogenetic hypotheses within the Bombycoidea proposed by Minet (1994: Entomologica scandinavica, 25, 63–88). The Brahmaeidae are paraphyletic relative to the Lemoniidae (syn.nov.), and the current concept of Bombycidae is polyphyletic, with the bombycid subfamily Apatelodinae being part of a monophylum comprising Brahmaeidae / Lemoniidae, Eupterotidae and Apatelodidae (stat.rev.).
In vitroandin vivoevaluation of a potentiated miconazole aural solution in chronicMalasseziaotitis externa in dogs
Authors: Hensel Patrick , Austel Michaela , Wooley Richard E. , Keys Deborah , Ritchie Branson W.
Published: September 2010

This study assessed thein vitroandin vivoactivity of an ear solution containing a third‐generation chelating agent (Tricide®) as an antimicrobial potentiator for miconazole in chronicMalasseziaotitis. Thirty‐one ears from 20 dogs were enrolled in the study. Fungal culture, minimum inhibitory concentration (MIC), and minimum fungicidal concentration (MFC) testing of miconazole with and without Tricide®were performed on all ears. In a randomized, controlled, and blinded treatment trial the ears were treated either with 0.9% saline solution containing 0.01% miconazole, 0.03% dexamethasone and 540 μg/mL Tricide®or the same solution without Tricide®. Cytologic and auroscopic examinations were conducted on day 0, 14 and 28 and evaluated for number of yeast organisms, degree of erythema, hyperplasia and amount of discharge. Thein vitrodata was compared with Wilcoxon signed‐rank test. The cytologic and auroscopic scores were compared between the visits and treatment groups at day 0, 14 and 28 using a Wilcoxon–Mann–Whitney test and repeated measures analysis. MIC and MFC were significantly (P < 0.0001) reduced when miconazole was combined with the chelating agent versus miconazole alone. The cytologic scores were significantly lower on days 14 (P = 0.0156) and 28 (P = 0.0280) for the group treated with Tricide®. The auroscopic scores decreased significantly by the end of the trial compared to day 0, but the difference between the two groups was not significant. This study suggests that Tricide®enhancesin vitroactivity andin vivoefficacy againstMalasseziasp. in dogs with yeast otitis.
Differential interaction of branch‐specific inhibitors of isoprenoid biosynthesis with cell cycle progression in tobacco BY‐2 cells
Authors: Andréa Hemmerlin , Fischt Isabelle , Bach Thomas J.
Published: September 2010

3‐Hydroxy‐3‐methylglutaryl‐coenzyme A (HMG‐CoA) reductase (HMGR), which catalyzes the formation of mevalonic acid (MVA), can be specifically blocked by mevinolin. Inhibition of HMGR in vivo leads to an arrest in cell cycle progression in tobacco (Nicotiana tabacum L. Bright Yellow 2) cells. As MVA in plants is the common precursor of a myriad of isoprenoid products synthesized in the cytosol and mitochondria, it is difficult to identify among such MVA‐dependent molecules those whose lack may lead to cell cycle arrest. In an attempt to do so, branch‐specific inhibitors of the cytosolic isoprenoid pathway downstream from MVA were used to study their capacity to block cell cycle progression. The effects of squalestatin (sterol biosynthesis inhibitor), chaetomellic acid A and patulin (protein prenyltransferase (PT) inhibitors) and tunicamycin (inhibitor of dolichol‐dependent protein glycosyl transferase, thus mimicking the effect of an absence of dolichol) were compared to those induced by mevinolin. In this way, squalestatin and chaetomellic acid were identified as behaving like true cell cycle inhibitors, in that they led to a specific arrest in the cell cycle. However, they did not exactly mimic the mevinolin‐induced effects. Patulin proved to be of high general toxicity, which suggests that it may affect other reactions besides blockage of protein isoprenylation. Finally, tunicamycin efficiently blocked growth of cell suspension cultures, but did not arrest the cells in a specific phase of the cell cycle. Results are discussed in the context of a better understanding of the essential implication of isoprenoids in plant cell cycle progression.
Molecular cloning and characterization of a high DP fructan: fructan 1‐fructosyl transferase from Viguiera discolor (Asteraceae) and its heterologous expression in Pichia pastoris
Authors: Van den Ende Wim , Van Laere André , Le Roy Katrien , Vergauwen Rudy , Boogaerts David , Figueiredo‐Ribeiro Rita C. L. , Machado de Carvalho Maria Angela
Published: September 2010

Inulin‐type fructans are stored in the tuberous roots of the Brazilian cerrado plant Viguiera discolor Baker (Asteraceae). In Cynara scolymus (artichoke) and Echinops ritro (globe thistle), the fructans have a considerably higher degree of polymerization (DP) than in Cichorium intybus (chicory) and Helianthus tuberosus (Jerusalem artichoke). It was shown before that the higher DP in some species can be attributed to the properties of their fructan: fructan 1‐fructosyl transferases (1‐FFTs; EC 2.4.1.100), enzymes responsible for chain elongation. Here, we describe the cloning of a high DP (hDP) 1‐FFT cDNA from V. discolor and its heterologous expression in Pichia pastoris. Starting from 1‐kestose and Neosugar P (a mixture of oligo‐inulins from microbial origin) as substrates, the recombinant enzyme produces a typical hDP inulin profile in vitro, closely resembling the one observed in vivo. The enzyme shows no invertase activity and sucrose: sucrose 1‐fructosyl transferase (1‐SST; EC 2.4.1.99) activity in vitro. Pattern evolution during incubation suggests that inulins with DP ≥ 6 are much better substrates than sucrose or lower DP oligo‐fructans. Because hDP inulin‐type fructans show superior properties for specific food and non‐food applications, the hDP 1‐FFT gene from V. discolor has potential for the production of hDP inulin in vitro or in transgenic crops.
NaCl treatment markedly enhances H2O2‐scavenging system in leaves of halophyte Suaeda salsa
Authors: Cai‐Hong Pang , Su‐Jun Zhang , Zhi‐Zhong Gong , Bao‐Shan Wang
Published: September 2010

The C3 halophyte Suaeda salsa L. grown under the high concentration of NaCl (200 mM) was used to investigate the role of the hydrogen peroxide (H2O2)‐scavenging system [catalase, ascorbate peroxidase, glutathione reductase (GR), ascorbic acid, and glutathione (GSH)] in removal of reactive oxygen species. The activity of catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and GR (EC 1.6.4.2) increased significantly after 7 days of NaCl treatment. The isoform patterns of CAT and GR were not affected, but the staining intensities were significantly increased by NaCl treatment. Activities of both the thylakoid‐bound APX or GR and stromal APX (S‐APX) or GR in the chloroplasts were markedly enhanced under high salinity. Fifty percent of APX in the chloroplasts is thylakoid‐bound APX. S‐APX and GR activity represented about 74–78 and 64–71% of the total soluble leaf APX and GR activity, respectively. Salt treatment increased the contents of ascorbic acid and GSH. By contrast, a decreased content of H2O2 was found in the leaves of NaCl‐treated S. salsa. The level of membrane lipid peroxidation decreased slightly after NaCl treatment. The plants grew well with high rate of net photosynthesis under high salinity. These data suggest that upregulation of the H2O2‐scavenging system in plant cells, especially in the chloroplasts, is at least one component of the tolerance adaptations of halophytes to high salinity.
Cytokinin biosynthesis and perception
Authors: Hwang Ildoo , Sakakibara Hitoshi
Published: September 2010

Cytokinin has been considered to be a master regulator of plant growth and development, but only in the past several years has substantial progress been made uncovering the roles of cytokinins at various developmental stages. Recent studies on key metabolic enzymes and signaling components have contributed to understanding the basic mechanism of biosynthesis and perception of cytokinin within a whole plant body. The initial products of de novo cytokinin biosynthesis in higher plants and Agrobacterium are different, and the regulatory systems in biosynthesis and homeostasis are finely controlled and appear to be important in communicating nutrient signals to morphogenetic responses. The cytokinin receptors have largely overlapping, but still specific, functions in diverse cytokinin responses. In this review, we will specifically emphasize the biosynthesis of isoprenoid cytokinins and perception of cytokinin signals in Arabidopsis.
Metabolomics for plant stress response
Authors: Shulaev Vladimir , Cortes Diego , Miller Gad , Mittler Ron
Published: September 2010

Stress in plants could be defined as any change in growth condition(s) that disrupts metabolic homeostasis and requires an adjustment of metabolic pathways in a process that is usually referred to as acclimation. Metabolomics could contribute significantly to the study of stress biology in plants and other organisms by identifying different compounds, such as by‐products of stress metabolism, stress signal transduction molecules or molecules that are part of the acclimation response of plants. These could be further tested by direct measurements, correlated with changes in transcriptome and proteome expression and confirmed by mutant analysis. In this review, we will discuss recent application of metabolomics and system biology to the area of plant stress response. We will describe approaches such as metabolic profiling and metabolic fingerprinting as well as combination of different ‘omics’ platforms to achieve a holistic view of the plant response stress and conduct detailed pathway analysis.