bluuebunny/crossref_metadata_2025 huggingface dataset:
Diminished cytokine signalling against bacterial components in mononuclear leucocytes from ulcerative colitis patients after leukocytapheresis
Authors: Mitsuyama K , Suzuki A , Matsumoto S , Tomiyasu N , Takaki K , Takedatsu H , Masuda J , Handa K , Harada K , Nishida H , Toyonaga A , Sata M
Published: June 2005

Infiltration by circulating inflammatory cells is a prominent local inflammatory feature of ulcerative colitis (UC). Several trials have suggested that leukocytapheresis by filtration can benefit patients with active UC. We investigated how this therapy might modulate the inflammatory response. Patients with active UC who were beginning repeated filtration leukocytapheresis were studied. Mononuclear cell preparations were obtained from blood before and after the first treatment, and expression of cytokine signalling components and the cell-proliferative response were analysed in vitro. Leukocytapheresis reduced lipopolysaccharide-induced production of proinflammatory cytokines (interleukin-1, -6, -8 and tumour necrosis factor-α, P < 0·05 for all) and activation of intracellular signalling components (nuclear factor-κB, mitogen-activated protein kinases, and signal transducer and activator of transcription-3), as well as surface expression of toll-like receptor-4 (P < 0·05) in mononuclear cells. The therapy also reduced the cell-proliferative response by mononuclear cells stimulated with sonicated bacterial preparations from autologous intestine (P < 0·05). These results indicate that activated mononuclear cells in the peripheral blood of patients with active UC are removed by leukocytapheresis and replaced by cells with a lower activation status. This replacement may partly explain the therapeutic benefit.
Engineering and functional evaluation of a single-chain antibody against HIV-1 external glycoprotein gp120
Authors: Wang H W , Cole D , Jiang W Z , Jin H T , Fu N , Chen Z L , Jin N Y
Published: June 2005

The HIV-1 envelope glycoprotein surface subunit gp120 is an attractive target for molecular intervention. This is because anti-HIV-1 gp120 neutralizing antibodies display the potential ability to inhibit HIV-1 infection. The present investigation describes the construction of a genetically engineered single chain antibody (scFv102) against HIV-1 gp120, its expression and functional evaluation. The parental hybridoma cell line (102) produces an immunoglobulin directed against the conserved CD4-binding region of gp120. cDNAs encoding the variable regions of the heavy (VH) and light (VL) chains were prepared by reverse transcription PCR and linked together with an oligonucleotide encoding a linker peptide (Gly4Ser)3 to produce a single chain antibody gene. The resulting DNA construct was cloned into a prokaryotic expression vector (pET28) and recombinant scFv102 was expressed in Eserichia coli as an insoluble protein. The denatured scFv102 was refolded and purified by immobilized metal ion affinity chromatography. Purified scFv102 had the same specificity as the intact IgG in immuno-blotting assays and immuno-fluorescence (IF) detection, but ELISA analyses demonstrated the affinity of scFv102 to be 5-fold lower than that of the parental monoclonal antibody. In neutralization assays, scFv102 at concentrations lower than 40 µg/ml exhibited efficient interference with viral replication and inhibition of viral infection (90%) across a range of primary isolates of subtype B HIV-1. These results suggest that the constructed anti-HIV-1 gp120 scFv102 has good biological activity and can potentially be used for in vitro diagnostic and in vivo therapeutic applications.
Expression of tumour necrosis factor receptor and Toll-like receptor 2 and 4 on peripheral blood leucocytes of human volunteers after endotoxin challenge: a comparison of flow cytometric light scatter and immunofluorescence gating
Authors: Wittebole X , Coyle S M , Kumar A , Goshima M , Lowry S F , Calvano S E
Published: June 2005

Toll-like receptors (TLRs) are involved in the recognition of bacterial products and thus participate in the induction of the inflammatory cascade. However, much less is known about the evolution of leucocyte TLR expression during human inflammatory stress. We hypothesized that a decrease in leucocyte TLRs could account for the so-called tolerance or hyporesponsiveness state to subsequent stimulation with bacteria-derived products. Because of the profound monocytopenia that ensues after in vivo lipopolysaccharide (LPS) challenge, we also compared monocyte TLR expression using two different techniques of flow cytometric gating. In a first set of experiments, 17 healthy volunteers underwent LPS challenge. Blood was drawn at different time-points and analysed by flow cytometry using light scatter gating and one-colour analysis to assess the expression of the tumour necrosis factor receptor (TNFR) and TLR2 and TLR4 on both monocytes and granulocytes. In a second set of experiments, the assessment of those receptors was made using a more specific gating method that utilized light scatter and CD14 immunofluorescence in a two-colour analysis. This was performed using whole blood drawn from five healthy volunteers and incubated ex vivo for different time periods with or without LPS and in 12 volunteers who underwent LPS challenge in vivo. The pattern of expression for monocyte TNFR was similar for both types of gating. Using only the light scatter gating, an initial drop of TLR 2 and 4 was observed on monocytes. By contrast, when using light scatter × immunofluorescence gating, an up-regulation of these two receptors following both in vivo and in vitro LPS exposure was observed. LPS up-regulates the expression of TLRs on monocytes and granulocytes. Depending upon the methodology utilized, contrasting results were obtained with respect to TLR2 and TLR4 expression. The flow cytometric gating technique used is of importance in determining cellular TLR2 and TLR4 expression, especially in blood samples exhibiting significant monocytopenia.
Immunogenicity and protective efficacy of the Mycobacterium tuberculosis fadD26 mutant
Authors: Infante E , Aguilar L D , Gicquel B , Pando R Hernandez
Published: June 2005

The Mycobacterium tuberculosis fadD26 mutant has impaired synthesis of phthiocerol dimycocerosates (DIM) and is attenuated in BALB/c mice. Survival analysis following direct intratracheal infection confirmed the attenuation: 60% survival at 4 months post-infection versus 100% mortality at 9 weeks post-infection with the wild-type strain. The fadD26 mutant induced less pneumonia and larger DTH reactions. It induced lower but progressive production of interferon (IFN)-γ, interleukin (IL)-4 and tumour necrosis factor (TNF)-α. Used as a subcutaneous vaccine 60 days before intratracheal challenge with a hypervirulent strain of M. tuberculosis (Beijing code 9501000), the mutant induced a higher level of protection than did Bacille Calmette–Guérin (BCG). Seventy per cent of the mice vaccinated with the fadD26 mutant survived at 16 weeks after challenge compared to 30% of those vaccinated with BCG. Similarly, there was less tissue damage (pneumonia) and lower colony-forming units (CFU) in the mice vaccinated with the fadD26 mutant compared to the findings in mice vaccinated with BCG. These data suggest that DIM synthesis is important for the pathogenicity of M. tuberculosis, and that inactivation of DIM synthesis can increase the immunogenicity of live vaccines, and increase their ability to protect against tuberculosis.
Adaptive radiation into ecological niches with eruptive dynamics: a comparison of tenthredinid and diprionid sawflies
Authors: PRICE PETER W. , ROININEN HEIKKI , OHGUSHI TAKAYUKI
Published: June 2005

We tested the hypothesis that the bottom‐up influence of coniferous plant resources promotes the probability of outbreak or eruptive dynamics in sawflies. The literature was examined for three geographical regions − North America north of Mexico, Europe and Japan.

In each region tenthredinid sawflies (Hymenoptera: Tenthredinidae) were significantly more likely to be eruptive on conifers than on angiosperms.

The diprionid sawflies (Hymenoptera: Diprionidae) that attack conifers exclusively showed a significantly higher probability of eruptive dynamics than the tenthredinid sawflies on angiosperms in two regions, North America and Europe, and in Japan the trend was in the same direction.

The probability of species showing eruptive dynamics on coniferous hosts was not significantly different among tenthredinids and diprionids on conifers in North America, Europe and Japan.

The weight of evidence supports the hypothesis of conifers supporting a higher percentage of eruptive species than angiosperms.

In the adaptive radiation of tenthredinid sawflies from flowering plants onto conifers, larches (Larix) appear to be particularly favourable for colonization, but pines (Pinus) have not been colonized in any region, a pattern likely to be explained by the growth characteristics of the host plants.

Among tenthredinid species in Europe, where sawfly/host relationships are best known, there is a significant trend for an increasing proportion of outbreaking species from herbs, to shrubs, to trees.

The results indicate for the first time the strong bottom‐up effects of plant resources on the population dynamics of sawflies, involving general features of host plant taxa and growth characteristics.
The lognormal distribution is not an appropriate null hypothesis for the species–abundance distribution
Authors: WILLIAMSON MARK , J. GASTON KEVIN
Published: June 2005

Of the many models for species–abundance distributions (SADs), the lognormal has been the most popular and has been put forward as an appropriate null model for testing against theoretical SADs. In this paper we explore a number of reasons why the lognormal is not an appropriate null model, or indeed an appropriate model of any sort, for a SAD.

We use three empirical examples, based on published data sets, to illustrate features of SADs in general and of the lognormal in particular: the abundance of British breeding birds, the number of trees > 1 cm diameter at breast height (d.b.h.) on a 50 ha Panamanian plot, and the abundance of certain butterflies trapped at Jatun Sacha, Ecuador. The first two are complete enumerations and show left skew under logarithmic transformation, the third is an incomplete enumeration and shows right skew.

Fitting SADs by χ2test is less efficient and less informative than fitting probability plots. The left skewness of complete enumerations seems to arise from a lack of extremely abundant species rather than from a surplus of rare ones. One consequence is that the logit‐normal, which stretches the right‐hand end of the distribution, consistently gives a slightly better fit.

The central limit theorem predicts lognormality of abundances within species but not between them, and so is not a basis for the lognormal SAD. Niche breakage and population dynamical models can predict a lognormal SAD but equally can predict many other SADs.

The lognormal sits uncomfortably between distributions with infinite variance and the log‐binomial. The latter removes the absurdity of the invisible highly abundant half of the individuals abundance curve predicted by the lognormal SAD. The veil line is a misunderstanding of the sampling properties of the SAD and fitting the Poisson lognormal is not satisfactory. A satisfactory SAD should have a thinner right‐hand tail than the lognormal, as is observed empirically.

The SAD for logarithmic abundance cannot be Gaussian.
Predatory activity and spatial pattern: the response of generalist carabids to their aphid prey
Authors: WINDER LINTON , ALEXANDER COLIN J. , HOLLAND JOHN M. , SYMONDSON WILLIAM O. C. , PERRY JOE N. , WOOLLEY CHRIS
Published: June 2005

The spatial distribution of cereal aphids infesting a field of winter wheat during the population establishment, development and decline phases were studied using a field‐scale grid of sampling locations.

The distribution of two generalist predators,Pterostichus melanariusandP. madidus, were sampled contemporaneously.

Using spatial analysis by distance indices (SADIE), spatial pattern in the aphid population, predator activity–density, predator hunger and aphid predation was detected and mapped.

We tested the hypothesis that carabids and aphids were spatially associated with one another through predation. Aphid predation by individual beetles was detected using enzyme‐linked immunosorbent assays (ELISA) and hunger was assessed by measurement of foregut weights.

Initially, there was a strong spatial dissociation between aphids andP. melanariusactivity–density. While the aphid population was increasing there was a strong spatial association between aphids and bothP. melanariusandP. madidusactivity–density. During aphid population decline there was no measurable association between aphids and predatory activity–density.

Predation of aphids was strongly locally associated with predator activity–density on all sample dates for both predator species, regardless of the association with aphid spatial pattern.

Areas within the field most isolated fromP. melanariuspredation had the highest rates of aphid population increase.

Although the proportion ofP. melanariusindividuals consuming aphids was much lower compared toP. madidus, it was concluded that it was a more effective biological control agent due to its comparative abundance.
Taxonomic diversity and biogeography of Chironomidae (Insecta: Diptera) in lakes of tropical West Africa using subfossil remains extracted from surface sediments
Authors: Eggermont Hilde , Verschuren Dirk , Dumont Henri
Published: June 2005

Aim This paper assesses whether chironomid (Insecta: Diptera) faunas of lakes in tropical West Africa and the central Sahara are biogeographically and ecologically sufficiently compatible with those of East African lakes to allow treating them as being derived from a single continent‐wide species pool, and to justify merging regional palaeoenvironmental data sets relating species distributions to abiotic environmental factors and microhabitats into a pan‐African data set.

Location Tropical West Africa (Cameroon and Gabon), central Sahara (Chad) and East Africa (Uganda, Kenya, Ethiopia).

Methods We employ three main approaches herein. First, we analyse the taxonomic diversity and distribution of larval Chironomidae in 12 regional study lakes using death assemblages of recently buried remains extracted from surface sediments. Secondly, we make taxonomic comparison with a similar analysis conducted in 73 East African lakes, and with checklists of Chironomidae species distribution in Africa. Thirdly, we present descriptions and illustrations of 21 West African morphotypes not previously encountered in surveys of East African Chironomidae based on subfossil larval remains.

Results This study involves 84 morphospecies or higher taxa, comprising 17 Tanypodinae, 14 Orthocladiinae, and 53 Chironominae (43 Chironomini; 10 Tanytarsini). As represented in our subfossil collections, the West African chironomid fauna shares at least 59 taxa (or 70.2% of faunal diversity) with the East African fauna, and a literature study also indicates that the majority of West African chironomid species are shared by the drier regions of North, East and Southern Africa. Freshwater lakes in tropical West Africa display a greater average taxon richness and diversity than freshwater lakes in East Africa, partly because Plio‐Pleistocene climate variation in West Africa was more favourable to species survival and accumulation (promoting beta‐diversity), and partly because current climatic and hydrological conditions in the region permit narrow niche differentiation and hence a more complex community structure (promoting alpha‐diversity). Freshwater lakes in East Africa, especially those located in the semi‐arid eastern Rift valleys of Kenya and Ethiopia, experience fluctuating hydrological regimes, which select for species able to tolerate a wide range of environmental conditions.

Conclusion Considerable species overlap between the larval chironomid faunas of the West and East African study lakes suggests that palaeoenvironmental calibration data sets from these two regions can be merged.
Characterization of polymer thin films by phase‐sensitive acoustic microscopy and atomic force microscopy: a comparative review
Authors: NGWA W. , LUO W. , KAMANYI A. , FOMBA K. W. , GRILL W.
Published: June 2005

The potential of phase‐sensitive acoustic microscopy (PSAM) for characterizing polymer thin films is reviewed in comparison to atomic force microscopy (AFM). This comparison is based on results from three‐dimensional vector contrast imaging and multimodal imaging using PSAM and AFM, respectively. The similarities and differences between the information that can be derived from the AFM topography and phase images, and the PSAM phase and amplitude micrographs are examined. In particular, the significance of the PSAM phase information for qualitative and quantitative characterization of the polymer films is examined for systems that generate surface waves, and those that do not. The relative merits, limitations and outlook of both techniques, individually, and as a complementary pair, are discussed.
Image analysis of X‐ray microtomograms of soft materials during convective drying: 3D measurements
Authors: LÉONARD A. , BLACHER S. , MARCHOT P. , PIRARD J.‐P. , CRINE M.
Published: June 2005

Drying dewatered sludge leads to a complex three‐dimensional porous structure. Moreover, this operation is dependent on the way the material is processed. In this study, textural changes of sludge extrudates submitted to convective drying are followed by a 3D image analysis of reconstructed X‐ray microtomograms. To achieve this goal, two different wastewater sludges collected in wastewater treatment plant after the thickening step and dewatered in the laboratory are used. It is showed that the evolution of the 3D‐crack ratio vs. the residual water content evolves following a hyperbolic law. The 3D opening crack size distribution reveals two different types of pore development, i.e. a continuous pore size evolution for one sludge and the sudden appearance of cracks for the other sludge.
A simple enzymatic method for examining calcite ossicles of Echinodermata
Authors: TIAGO C. G. , BRITES A. D. , KAWAUCHI G. Y.
Published: June 2005

The various shapes, size and fine details of ossicles are of paramount importance as systematic characters in the Echinodermata. The ossicles in this group are endodermal and a method to free them from the dermis is essential for their study. To date, a small quantity of hypochlorite solution (usually household liquid bleach) has been used to dissolve a small piece of tissue and, consequently, free these ossicles. A new method, using a proteolytic enzyme instead of hypochlorite solution to dissolve holothurian tissues, is proposed. This method was tested on fragments of body tissues from three species in three different orders of holothurians:Holothuria griseaSelenka, 1867 (Aspidochirotida),Duasmodactyla seguroensis(Deichmann, 1930) (Dendrochirotida) andSynaptula secretaAncona Lopez (1957) (Apodida). Observations of material prepared using the hypochlorite and the enzyme methods were made using scanning electron microscopy (SEM). The SEM images show the striking differences in the surface of the ossicles obtained by each method, and reveal the advantages of the enzyme method.
Archaeal transcription and its regulators
Authors: Geiduschek E. Peter , Ouhammouch Mohamed
Published: June 2005

The relatively complex archaeal RNA polymerases are constructed along eukaryotic lines, and require two initiation factors for promoter recognition and specific transcription that are homologues of the RNA polymerase II TATA‐binding protein and TFIIB. Many archaea also produce histones. In contrast, the transcriptional regulators encoded by archaeal genomes are primarily of bacterial rather than eukaryotic type. It is this combination of elements commonly regarded as separate and mutually exclusive that promises unifying insights into basic transcription mechanisms across all three domains of life.
Safe motherhood in Jamaica: from slavery to self‐determination
Authors: McCaw‐Binns Affette
Published: June 2005

The development of maternal health care in Jamaica is reviewed by examining government documents and publications to identify social and political factors associated with maternal mortality decline.

Modern maternity services began with the 1887 establishment of the Victoria Jubilee Hospital and Midwifery School. Community midwives were deployed widely by the 1930s and community antenatal care expanded in the 1950s. Social policies in the 1970s increased women's access to primary health care, education and social support; improved transportation in the 1990s facilitated hospital delivery.

Maternal mortality declined rapidly from ∼600/100 000 in the 1930s to 200/100 000 in 1960, led by a 69% decline in sepsis by 1950, and a 72% decline from all causes thereafter, settling at ∼100/100 000 in the 1980s. Skilled birth attendant deliveries moved from 39% in 1950 to 95% in 2001 and hospital births from 31% in 1960 to 91% in 2001.

Maternal mortality plateaued at 70–80% prevalence of skilled delivery care. Deployment of midwives into rural communities and social development focused on women and children were associated with the observed improvements. Further reductions will require greater attention to the quality of emergency obstetric care.
Management of late leaf spot of groundnut (Arachis hypogaea) with chlorothalonil‐tolerant isolates of Pseudomonas aeruginosa
Authors: Krishna Kishore G. , Pande S. , Podile A. R.
Published: June 2005

Fifteen groundnut‐associated bacterial isolates that inhibited by > 90% the in vitro conidial germination of Phaeoisariopsis personata, causal agent of late leaf spot disease of groundnut, were applied as a prophylactic spray (108 cfu mL−1) and tested for control of the disease in the glasshouse. Two groundnut seed‐associated bacterial isolates, GSE 18 and GSE 19, identified as Pseudomonas aeruginosa, reduced the lesion frequency (LF) by up to 70%. A 90‐day‐old peat‐based formulation of P. aeruginosa GSE 18 reduced LF measured 15 days postinoculation by up to 60%. Both P. aeruginosa GSE 18 and GSE 19 were tolerant to chlorothalonil (Kavach®) up to 2000 µg mL−1 in LB broth. In glasshouse trials, GSE 18 and GSE 19 tested in combination with reduced concentrations of chlorothalonil were highly efficient in management of the disease. The disease was completely controlled by chlorothalonil (> 250 µg mL−1), and in the presence of GSE 18 or GSE 19, 100 µg mL−1 chlorothalonil was equally effective. Application of rifamycin‐resistant mutants of GSE 18 or GSE 19 together with chlorothalonil significantly increased the survival of these isolates in the groundnut phylloplane. In the field, a combination of GSE 18 and 500 µg mL−1 chlorothalonil reduced disease severity comparable to 2000 µg mL−1 chlorothalonil alone. Use of chlorothalonil‐tolerant pseudomonads together with a quarter concentration of the recommended field dose of chlorothalonil doubled pod yield compared with the untreated unsprayed control.
Binucleate Rhizoctonia sp. AG G causing root rot in yacon (Smallanthus sonchifolius) in Brazil
Authors: Fenille R. C. , Ciampi M. B. , Souza N. L. , Nakatani A. K. , Kuramae E. E.
Published: June 2005

A new rot caused by a binucleate Rhizoctonia sp. affecting the tuberous root cortex of the domesticated yacon (Smallanthus sonchifolius) has been observed in Brazil. Isolates of a binucleate Rhizoctonia sp. were collected from roots with rot symptoms and characterized by the number of nuclei per cell, hyphal anastomosis, RAPD molecular markers, ITS‐5·8S rDNA sequence and pathogenicity tests. All isolates had a mean of 1·9–2·2 nuclei per cell and anastomosed with the binucleate Rhizoctonia sp. AG G‐tester strain. RAPD analysis was carried out between 11 isolates recovered from yacon and 11 AG (A, Ba, Bb, Bo, C, D, F, G, O, P, Q) standard testers of binucleate Rhizoctonia sp. Genetic similarities of 94·8–100% were observed among isolates of the binucleate Rhizoctonia sp. from yacon and all isolates were genetically more closely related to the AG G tester than other strains according to upgma analysis using RAPD markers. Homologies of complete ITS nucleotide sequences were 100% between binucleate isolates of Rhizoctonia sp. from yacon and the AG G tester. According to pathogenicity tests, the isolates caused typical rot symptoms of yacon tubers 90 days after inoculation
Modelling the effects of wetness duration and fruit maturity on infection of apple fruits of Cox's Orange Pippin and two clones of Gala by Venturia inaequalis
Authors: Xu X. M. , Robinson J.
Published: June 2005

The effects were investigated of fruit maturity and duration of wetness on infection of apple fruits by Venturia inaequalis, and subsequent scab development. Incubation rate (inverse of median incubation period) increased linearly with increasing temperature (5–20°C) on detached 5‐week‐old fruits of cv. Royal Gala. Fruits were highly susceptible in the early stages of development, but became increasingly resistant as they matured. Inoculation of attached 12‐week‐old and detached near‐mature fruits did not result in any lesions, while inoculation of attached 4‐, 5‐, 7‐ and 9‐week‐old fruits resulted in various levels of infection. Fruits of cv. Mondial Gala were more susceptible than those of cv. Cox's Orange Pippin. On cv. Mondial Gala, a wet period of 9 h resulted in ≈ 90% infection of 4‐week‐old fruits, but only 9% infection of 9‐week‐old fruits. Numbers of scab lesions on an apple generally followed a Neyman type A rather than a Poisson distribution, indicating a certain degree of aggregation of lesions on a fruit. A two‐parameter generalization of the Poisson model described the observed incidence–density relationship well. A longer duration of wetness was required to result in a similar level of scab infection on old fruits to that on young fruits. On cv. Mondial Gala, wet periods of 9 and 32 h were required for ≈ 90% incidence of fruit scab on 4‐ and 7‐week‐old fruits, respectively. A mathematical model was developed to relate the incidence of fruit scab to duration of wetness and fruit maturity. The potential use of these results in practical disease management is discussed.
Resistance of potato genotypes to common and netted scab‐causing species ofStreptomyces
Authors: Pasco C. , Jouan B. , Andrivon D.
Published: June 2005

Common and netted scabs are two disfiguring bacterial diseases of potato tubers, caused by various groups ofStreptomycesspecies. Common scab, caused primarily byStreptomyces scabiesandStreptomyces europaeiscabiei, is characterized by more or less deep pustules on the tuber surface, while symptoms of netted scab, caused mainly byStreptomyces reticuliscabiei, are superficial, corky alterations of the tuber periderm. Some isolates ofS. europaeiscabieiare able to induce both common and netted scab symptoms, and therefore constitute a third pathogenicity group. Like most bacterial diseases, potato scabs would be best controlled by using resistant cultivars. Repeated experiments with soil artificially infested with isolates of three species representative of the three pathogenicity groups showed the level and stability of cultivar resistance, as well as the existence of a range of aggressiveness among different isolates. The distribution of scab severity indexes recorded on a collection of 16 potato cultivars and 27 breeding clones grown in soil infested with common scab‐inducing isolates was continuous, suggesting isolate nonspecific quantitative resistance. Least susceptible cultivars were Nicola, BF15, Sirtéma, and Charlotte, while Urgenta, Désirée, Ondine and Bintje were very susceptible. The same genotypes proved either highly susceptible (e.g. cvs Bintje, Désirée or Carmine) or highly resistant (e.g. cvs Charlotte, Sirtéma, Monalisa, BF15 or Belle de Fontenay) to isolates forming netted scab symptoms, suggesting isolate‐specific qualitative resistance. The ability was confirmed of some isolates ofS. europaeiscabieito induce one or the other type of symptoms depending on cultivar and soil temperature.
The contribution of ground‐level inoculum of Fusarium culmorum to ear blight of winter wheat
Authors: Bateman G. L.
Published: June 2005

In a series of field experiments in eastern England over 5 years, severe ear blight developed only in plots of winter wheat that were inoculated by spraying with conidial suspensions of Fusarium culmorum during anthesis, and in which infection was encouraged by rainfall or mist irrigation. In the absence of artificial inoculation of the ears, F. culmorum caused less extensive ear blight, and only where soil‐surface inoculum was available after its application on infested plant material (colonized oat grains) up to 3–4 weeks before anthesis; it then developed most where significant rainfall occurred close to the time of anthesis. A warm, dry period following application of inoculum to the ground in late March contributed to increased infection of grain by F. culmorum, although ear blight was not increased. Ear infection therefore depended on adequate viable inoculum on infested plant debris within the crop, and conditions tending to favour brown foot rot development as well as, subsequently, rainfall and moist conditions during anthesis. These conditions did not occur together naturally during this period. Seedling infection by F. culmorum or Microdochium nivale made no significant contribution to ear blight. Inoculation of ears at anthesis with M. nivale or a locally obtained isolate of F. langsethiae did not produce ear blight symptoms. Possibilities for minimizing the availability of inoculum of F. culmorum and the implications for various options for ear‐blight control are discussed.
Susceptibility of invasive taxa of European blackberry to rust disease caused by the uredinial stage of Phragmidium violaceum under field conditions in Australia
Authors: Evans K. J. , Jones M. K. , Roush R. T.
Published: June 2005

European blackberry (Rubus fruticosus agg.) is an aggregate of closely related taxa, with at least 15 taxa naturalized in Australia. Biological control of this Weed of National Significance, using the nonindigenous rust fungus Phragmidium violaceum, is effective when the weather is conducive to multiple cycles of infection, but some blackberry taxa escape severe disease. Thirty‐one taxa of naturalized R. fruticosus agg. from southeastern Australia were isolated, their DNA phenotype determined and clones of each taxon inoculated with P. violaceum isolate SA1. Disease development was monitored for at least four generations of uredinia on large potted plants under field conditions. Although variation in mean disease severity appeared continuous over the range of Rubus clones tested, counts of uredinia and telia enabled identification of eight resistant taxa. Fine scale variation in susceptibility to rust disease was observed when different clones of R. leucostachys with the same DNA phenotype were found to express either resistance or susceptibility to P. violaceum (SA1). There were significant differences among 23 Rubus taxa rated as susceptible to rust disease in the mean number of leaves emerging per latent period of uredinia (LELPU). Mean LELPU appeared to account for some of the variation in two measures of mean disease severity observed among susceptible Rubus clones, although the correlation was insignificant (0·10 < P > 0·05).
Genetic characterization ofGremmeniella abietinavar.abietinaisolates from Spain
Authors: Santamaría O. , Alves‐Santos F. M. , Diez J. J.
Published: June 2005

The taxonomic placement of Spanish isolates ofGremmeniella abietinavar.abietina(Gaa) (race and biotype) was determined, for the first time, using RAPD markers and comparison of RAPD patterns for Spanish isolates and those originating from different regions of Europe and North America. Fifteen Spanish isolates of Gaa were isolated from recently dead shoots of 10Pinus halepensistrees. Additionally, 17 isolates of Gaa from Canada, Finland, Switzerland and the USA, previously characterized according to race and biotype, were used. Five primers, previously reported to yield readable, reproducible and polymorphic fragments, were used in PCR reactions. The results showed that the Spanish isolates represent the European race and not the Alpine or northern biotypes. Spanish isolates appear to be clearly separated from all other biotypes within the EU race and preliminary data suggest that Spanish isolates have low genetic variability.
Stability of resistance to Phytophthora infestans in potato: an international evaluation
Authors: Forbes G. A. , Chacón M. G. , Kirk H. G. , Huarte M. A. , Van Damme M. , Distel S. , Mackay G. R. , Stewart H. E. , Lowe R. , Duncan J. M. , Mayton H. S. , Fry W. E. , Andrivon D. , Ellissèche D. , Pellé R. , Platt H. W. , MacKenzie G. , Tarn T. R. , Colon L. T. , Budding D. J. , Lozoya‐Saldaña H. , Hernandez‐Vilchis A. , Capezio S.
Published: June 2005

Ten institutions in nine countries joined together to test the stability of resistance of 14 potato genotypes to the oomycete pathogen Phytophthora infestans in three separate trials. Seven of the genotypes were tested in one trial involving seven locations, and all 14 were tested in two subsequent trials, each involving eight locations. Stability of resistance was tested with nonparametric tests and with an additive main effects and multiplicative interaction (AMMI) model. Overall, resistance to P. infestans was robust; resistant genotypes were consistently resistant in all locations and trials. The nonparametric analysis indicated that specific genotypes were basically stable across sites for resistance. In trial 3, the Z statistic for overall stability was significant at 0·05%, indicating a significant level of interaction across the trial, but there were no significant interactions for specific genotypes in this trial. The genotype by environment (G × E) effect of the AMMI model was highly significant in both trials, but the mean square of G × E was less than 10% of the genotype effect in each trial. The first two principal components (PCA1 and PCA2) of the AMMI analyses together explained 75 and 80% of the interaction effects in trials 2 and 3, respectively. Based on both nonparametric and AMMI analyses, Ecuador and Argentina were locations of relatively high interaction effects for both trials 2 and 3, although in Ecuador this interaction was not associated with any particular potato genotype. Other locations also had high interaction effects, but these occurred in only one trial. The genotypes Chata Blanca and, to a lesser extent, Torridon were relatively unstable in trials 2 and 3, but in the case of Torridon, resistant, this did not represent a significant loss of resistance.
Effects of temperature and continuous and interrupted wetness on the infection of pear leaves by conidia of Venturia nashicola
Authors: Li B.‐H. , Xu X.‐M. , Li J.‐T. , Li B.‐D.
Published: June 2005

Experiments were conducted to determine: (i) the effects of temperature and duration of continuous wet periods on the infection of pear seedlings by conidia of Venturia nashicola, the causal agent of pear scab; and (ii) the effects of the length and temperature of dry interrupting periods on the mortality of infecting conidia. Average number of scab lesions per leaf increased with increasing duration of wetness. Logistic models adequately described the change in the average number of scab lesions per leaf at 5, 10, 15, 20 and 25°C over the wetness duration. At 30°C, only a few lesions developed. Simple polynomial models satisfactorily described the relationship of the three logistic model parameters (maximum number of lesions, rate of appearance and the time to 50% of the maximum number of lesions) with temperature. The optimum temperature for infection was found to be approximately 20°C. The relationship between mortality and the length of a dry period interrupting an infection process can be satisfactorily described by an exponential model. The rate of mortality at 10, 16 and 22°C did not differ significantly, but was significantly less than that at 28°C.
Responses to Free Lipopolysaccharide and Escherichia coli by Normal Human Intestinal Macrophages, Following their Migration out of the Lamina Propria
Authors: Austin A. S. , Judge H. M. , Robins R. A. , Cockayne A. , Mahida Y. R.
Published: June 2005

Intestinal macrophage responses to luminal bacteria and their constituents are important in mucosal inflammatory responses. We investigated the responses of intestinal macrophages to free lipopolysaccharide (LPS) and Escherichia coli. Macrophages were isolated from normal terminal ileum and colon by allowing them to migrate out of the lamina propria of mucosal samples denuded of epithelial cells. Following exposure to free LPS or fluorescein‐labelled E. coli, responsiveness was studied by intracellular expression of tumour necrosis factor‐α (TNF‐α). CD14, CD33, CD68, TLR2 and TLR4 expression was studied by fluorescence‐activated cell sorter (FACS). TLR and NOD2 expression was confirmed by reverse‐transcriptase polymerase chain reaction (RT‐PCR). CD14 was expressed by 36.5 ± 4.0% of the macrophages obtained following migration out of the lamina propria. These cells also expressed TLR2, TLR4 and NOD2. Of cells exposed to free LPS or those that had taken up E. coli, a greater proportion of CD14+ than CD14– macrophages expressed intracellular TNF‐α. Moreover, a greater proportion of macrophages (CD14+ and CD14–) demonstrated responses to E. coli than free LPS. In conclusion, a proportion of macrophages obtained following migration out of the lamina propria of normal terminal ileal and colonic mucosal samples express CD14, TLR2 and TLR4. These cells respond to free LPS and E. coli, as demonstrated by the expression of TNF‐α.
Milk‐Derived GM3 and GD3 Differentially Inhibit Dendritic Cell Maturation and Effector Functionalities
Authors: Brønnum H. , Seested T. , Hellgren L. I. , Brix S. , Frøkiær H.
Published: June 2005

Gangliosides are complex glycosphingolipids, which exert immune‐modulating effects on various cell types. Ganglioside GD3 and GM3 are the predominant gangliosides of human breast milk but during the early phase of lactation, the content of GD3 decreases while GM3 increases. The biological value of gangliosides in breast milk has yet to be elucidated but when milk is ingested, dietary gangliosides might conceptually affect immune cells, such as dendritic cells (DCs). In this study, we address the in vitro effect of GD3 and GM3 on DC effector functionalities. Treatment of bone marrow‐derived DCs with GD3 before lipopolysaccharide‐induced maturation decreased the production of interleukin‐6 (IL‐6), IL‐10, IL‐12 and tumor necrosis factor‐α as well as reduced the alloreactivity in mixed leucocyte reaction (MLR). In contrast, only IL‐10 and IL‐12 productions were significantly inhibited by GM3, and the potency of DCs to activate CD4+ cells in MLR was unaffected by GM3. However, both gangliosides suppressed expression of CD40, CD80, CD86 and major histocompatibility complex class II on DCs. Because GD3 overall inhibits DC functionalities more than GM3, the immune modulating effect of the ganglioside fraction of breast milk might be more prominent in the commencement of lactation during which the milk contains the most GD3.
A Full Flora, but not Monocolonization by Escherichia coli or Lactobacilli, Supports Tolerogenic Processing of a Fed Antigen
Authors: Rask C. , Evertsson S. , Telemo E. , Wold A. E.
Published: June 2005

Fed protein undergoes processing and coupling to major histocompatibility complex (MHC) II molecules during passage through the intestinal epithelium, generating a tolerogenic form of the antigen in serum. Transfer of this factor to naïve animals induces tolerance in the recipient. In this study, we investigate what impact colonization with Gram‐positive (Lactobacillus plantarum) or Gram‐negative (Escherichia coli) bacteria has on tolerogenic processing in the gut. Germ‐free (GF), monocolonized or conventional mice were fed ovalbumin (OVA), and their serum was collected and transferred to naïve conventional recipients that were tested for delayed‐type hypersensitivity against OVA after parenteral immunization. A transferable tolerogenic factor was produced by conventional mice, but not by mice that were germ free or monocolonized with either E. coli or L. plantarum. Conventional, but neither GF nor monocolonized mice showed upregulation of MHCII expression in the epithelium of small intestine. The results suggest that a complex intestinal microflora is needed to support oral tolerance development.
Simultaneous Expression and Detection of Multiple Retroviral Constructs in Haematopoietic Cells After Bone Marrow Transplantation
Authors: Nyakeriga A. M. , Djerbi M. , Malinowski M. M. , Grandien A.
Published: June 2005

Due to the complexity and redundancy of molecular processes governing the development and function of haematopoietic cells, experimental procedures allowing simultaneous alteration in gene expression of multiple genes in vivo are needed. Here, we describe a protocol allowing for simultaneous transduction of haematopoietic stem cells (HSC) with two different replication incompetent retroviral expression vectors followed by transplantation of lethally irradiated recipient mice. These bicistronic retroviral vectors carried genes for the enhanced green and yellow florescent proteins (EGFP and EYFP) respectively. Spleen cells from reconstituted animals were stained for common lymphocyte and myeloid markers, then analysed on a two‐laser, 488 and 635 nm, flow cytometer equipped with a 510/20‐nm bandpass filter for FL1, a 550/30‐nm bandpass filter for FL2 and a 530‐nm short‐pass dichroic mirror. It was demonstrated that cells expressing EGFP, EYFP or combinations thereof could be distinguished and analysed for staining with PerCP‐ and APC‐conjugated reagents. We found that a sizable proportion of cells (70%) from reconstituted animals expressed EGFP and/or EYFP and that expression of these genes did not affect lymphoid or myeloid development. We also demonstrated that the alternative optical configuration allowed for conventional multiparameter flow cytometric analyses.
CD45RA and RO Isoforms Have Distinct Effects on Cytokine‐ and B‐Cell‐Receptor‐Mediated Signalling in Human B cells
Authors: Mättö M. , Nuutinen U.‐M. , Ropponen A. , Myllykangas K. , Pelkonen J.
Published: June 2005

The common leucocyte antigen, CD45, is widely expressed on the surface of lymphocytes. In T and B cells, CD45 has an important role in the early events of receptor signalling. However, the role of various CD45 isoforms in B‐cell receptor (BCR)‐ and cytokine‐induced signalling and proliferation is still unclear.

In the present study, we establish two follicular lymphoma cell lines expressing either CD45RA (HF28RA) or CD45R0 (HF28R0) isoforms. It was observed that the two isoforms had distinct effects on BCR‐ or cytokine‐induced cellular proliferation. BCR stimulation significantly increased the proliferation of HF28R0 cells, in contrast to a decreased proliferation of HF28RA cells. Moreover, proliferation of HF28R0 cells significantly increased after the addition of interleukin‐2 (IL‐2), IL‐4, IL‐6, IL‐10, IL‐12, IL‐13, IL‐15, interferon‐γ and tumour necrosis factor‐α cytokines, whereas most of these cytokines significantly inhibited the proliferation of HF28RA cells. In addition, the cell lines had their individual cytokine mRNA expression profiles after BCR stimulation. We also analysed the effect of CD45 isoforms on intracellular signalling after BCR stimulation. It was found out that the kinetics of ERK1/2 MAP kinase phosphorylation was clearly faster in HF28R0 than in HF28RA cells. The phosphorylation of other analysed MAP kinases or PTKs was very similar in the cell lines.
Expression of the Virulence Factor, BfpA, by Enteropathogenic Escherichia coli is Essential for Apoptosis Signalling but not for NF‐κB Activation in Host Cells
Authors: Melo A. R. , Lasunskaia E. B. , De Almeida C. M. C. , Schriefer A. , Kipnis T. L. , Dias da Silva W.
Published: June 2005

Localized adherence (LA) of enteropathogenic Escherichia coli (EPEC) to epithelial cells results in attaching and effacing of the surface of these cells. LA depends on the gene bfpA, which codes for the BfpA protein. We found that EPEC‐E. coli adherence factor (EAF)(+), expressing BfpA, significantly reduced HeLa cell viability in comparison with EPEC‐EAF(–), as evaluated by the mitochondrial‐dependent succinate dehydrogenase conversion of 3′‐[4,5,‐dimethylthiazol‐2yl]2,5‐diphenyltetrazolium bromide (MTT) to its formazan. Apoptosis accounts for a substantial loss of the cell viability, because the cells incubated with EPEC‐EAF(+) or with cloned BfpA (data not shown), but not with EPEC‐EAF(–), were positive for annexin‐V binding, demonstrated chromatin condensation and nuclei fragmentation and exhibited a high level of caspase‐3 activity. Because the blockade of bacterial cell‐surface‐associated BfpA by anti‐BfpA immunoglobulin (Ig)Y antibody suppressed apoptotic death induced by EPEC‐EAF(+), BfpA may be the trigger for apoptosis. Both EPEC‐EAF(+) and EPEC‐EAF(–), as well as recombinant BfpA (data not shown), activated nuclear factor (NF)‐κB in a similar manner as analysed by the electrophoretic mobility shift assay (EMSA). EMSA supershift analysis demonstrated the presence of p65/RelA in a DNA‐binding complex. In contrast to DNA binding, NF‐κB‐dependent reporter gene transactivation was stimulated more strongly by EPEC B171/EAF(+), suggesting a role for this virulence factor in the regulation of transcriptional activity of NF‐κB. Because suppression of NF‐κB activation by BAY11‐7085, a NF‐κB inhibitor, neither induced apoptosis by itself nor blocked apoptosis induction by EPEC‐EAF(+), it may be suggested that apoptosis is not regulated by the NF‐κB pathway in HeLa cells.
Flow and turbulence structure across the ripple–dune transition: an experiment under mobile bed conditions
Authors: SCHINDLER ROBERT J. , ROBERT ANDRÉ
Published: June 2005

Current knowledge of flow and turbulent processes acting across the sand bed continuum is still unable to unequivocally explain the mechanism(s) by which ripples become dunes. Understanding has been improved by comparative high‐resolution studies undertaken over fixed bedforms at different stages in the continuum. However, these studies both ignore the role of mobile sediment and do not examine flow structure during the actual transition from ripples to dunes. The aims of the paper are: (i) to describe flow and turbulence characteristics acting above mobile bedforms at several stages across the transition; and (ii) to compare these data with those arising from experiments over fixed ripples and dunes. Laboratory experiments are presented that examine the turbulence structure across seven distinct stages of the transition from ripples to dunes. Single‐point acoustic Doppler velocimeter sampling at three flow heights above a developing mobile boundary was undertaken. Time‐averaged statistics and the instantaneous quadrant record reveal distinct changes in flow structure either side of the change from ripples to dunes. Initially, shear‐related, high‐frequency vortex shedding dominates turbulence production. This increases until two‐dimensional (2D) dunes have formed. Thereafter, turbulence intensities and Reynolds stress decline and three‐dimensional dunes exhibit values found over 2D ripples. This is the result of shear layer dampening which occurs when the topographically‐accelerated downstream velocity increases at a faster rate than flow depth. Activity at reattachment increases due to high velocity fluid imparting high mass and momentum transfer at the bed and/or wake flapping. Suspended sediment may also play a role in turbulence dampening and bed erosion. Ejections dominate over sweeps in terms of event frequency but not magnitude. Strong relationships between inward interactions and sweeps, and ejections and outward interactions, suggest that mass and momentum exchanges are dependent upon activity in all four quadrants. The results contradict the notion present in most physical models that larger bedforms exhibit most shear layer activity. Consequently an improved model for the ripple–dune transition is proposed.