bluuebunny/crossref_metadata_2025 huggingface dataset:
Lymphocytes are detrimental during the early innate immune response against Listeria monocytogenes
Authors: Carrero Javier A. , Calderon Boris , Unanue Emil R.
Published: March 2006

Mice deficient in lymphocytes are more resistant than normal mice to Listeria monocytogenes infection during the early innate immune response. This paradox remains unresolved: lymphocytes are required for sterilizing immunity, but their presence during the early stage of the infection is not an asset and may even be detrimental. We found that lymphocyte-deficient mice, which showed limited apoptosis in infected organs, were resistant during the first four days of infection but became susceptible when engrafted with lymphocytes. Engraftment with lymphocytes from type I interferon receptor–deficient (IFN-αβR−/−) mice, which had reduced apoptosis, did not confer increased susceptibility to infection, even when the phagocytes were IFN-αβR+/+. The attenuation of innate immunity was due, in part, to the production of the antiinflammatory cytokine interleukin 10 by phagocytic cells after the apoptotic phase of the infection. Thus, immunodeficient mice were more resistant relative to normal mice because the latter went through a stage of lymphocyte apoptosis that was detrimental to the innate immune response. This is an example of a bacterial pathogen creating a cascade of events that leads to a permissive infective niche early during infection.
Targeting protein–protein interactions by rational design: mimicry of protein surfaces
Authors: Fletcher Steven , Hamilton Andrew D
Published: March 2006

Protein–protein interactions play key roles in a range of biological processes, and are therefore important targets for the design of novel therapeutics. Unlike in the design of enzyme active site inhibitors, the disruption of protein–protein interactions is far more challenging, due to such factors as the large interfacial areas involved and the relatively flat and featureless topologies of these surfaces. Nevertheless, in spite of such challenges, there has been considerable progress in recent years. In this review, we discuss this progress in the context of mimicry of protein surfaces: targeting protein–protein interactions by rational design.
The snail's love-dart delivers mucus to increase paternity
Authors: Chase Ronald , Blanchard Katrina C
Published: March 2006

Many of the seemingly bizarre animal behaviours can be understood only by acknowledging the power of sex to shape evolution. A case in point is the so-called love-dart that some terrestrial molluscs shoot at their prospective sexual partners. Given that the likelihood of copulation is not different after solid hits than after complete misses, why do these suitors act so violently towards their chosen mates? Previously, it was shown that successful dart shooting enhances paternity. We conducted an experiment to determine whether the dart achieves its effect by a purely mechanical action or by transferring a bioactive substance. We found that injections of mucus from a gland associated with the dart more than doubled paternity relative to injections of saline. These results support the hypothesis that the dart transfers a substance capable of reconfiguring the spermatophore-receiving organs. While dart shooting probably evolved as the result of sperm competition, a role for cryptic female choice cannot be excluded. Our results imply that if cryptic female choice is operating in this system, it is likely to be based on the properties of the mucus and not on properties of the dart itself. Since we also found evidence of early-male sperm precedence, we conclude that snails can optimize their reproductive success by mating with virgins and shooting their darts accurately.
Origins and evolution of the Europeans' genome: evidence from multiple microsatellite loci
Authors: Belle Elise M.S , Landry Pierre-Alexandre , Barbujani Guido
Published: March 2006

There is general agreement that the current European gene pool is mainly derived from Palaeolithic hunting–gathering and Neolithic farming ancestors, but different studies disagree on the relative weight of these contributions. We estimated admixture rates in European populations from data on 377 autosomal microsatellite loci in 235 individuals, using five different numerical methods. On average, the Near Eastern (and presumably Neolithic) contribution was between 46 and 66%, and admixture estimates showed, with all methods, a strong and significant negative correlation with distance from the Near East. If the assumptions of the model are approximately correct, i.e. if the Basques' and Near Easterners' genomes represent a good approximation to the Palaeolithic and Neolithic settlers of Europe, respectively, these results imply that half or more of the Europeans' genes are descended from Near Eastern ancestors who immigrated in Europe 10 000 years ago. If these assumptions are incorrect, our results show anyway that clinal variation is the rule in the Europeans' genomes and that lower estimates of Near Eastern admixture obtained from the analysis of single markers do not reflect the patterns observed at the genomic level.
Developing detailed records of relative sea-level change using a foraminiferal transfer function: an example from North Norfolk, UK
Authors: Edwards Robin J , Horton B.P
Published: March 2006

This paper provides a brief overview of the transfer function approach to sea-level reconstruction. Using the example of two overlapping sediment cores from the North Norfolk coast, UK, the advantages and limitations of the transfer function methodology are examined. While the selected cores are taken from different sites, and display contrasting patterns of sedimentation, the foraminiferal transfer function distils comparable records of relative sea-level change from both sequences. These reconstructions are consistent with existing sea-level index points from the region but produce a more detailed record of relative sea-level change. Transfer functions can extract sea-level information from a wider range of sedimentary sub-environments. This increases the amount of data that can be collected from coastal deposits and improves record resolution. The replicability of the transfer function methodology, coupled with the sequential nature of the data it produces, assists in the compilation and analysis of sea-level records from different sites. This technique has the potential to bridge the gap between short-term (instrumental) and long-term (geological or geophysical) records of sea-level change.
Sea-level, topographical and sediment supply controls on Holocene sediment composition in the Humber Estuary, UK
Authors: Rees John G
Published: March 2006

To increase our understanding of the relative control of antecedent topography, sediment supply and sea-level change on grain size and organic content in the Humber Estuary, the composition of its Holocene fill over space and time has been evaluated. A model based-upon bed-by-bed description of over 3500 boreholes was sub-horizontally ‘sliced’ to analyse the composition of sediments in different parts of the estuary across the entire fill, as well as solely within estuary marginal sequences. Results demonstrate that different physiographic parts of the estuary are characterized by distinctive vertical sediment profiles that reflect the relative control of antecedent topography as well as sea-level upon them. The results raise questions about the processes controlling sand and gravel abundance in marginal sequences, where the estuary is physiographically most constrained. This semi-quantitative evaluation, the first of its kind on an estuarine fill, provides a technique for interpreting the relative importance of controls on an estuarine system, but highlights the need for improved modelling of estuarine channel form and dynamics over centurial to millennial time-scales.
Comparative genomics and genome evolution in yeasts
Authors: Wolfe Kenneth H
Published: March 2006

Yeasts provide a powerful model system for comparative genomics research. The availability of multiple complete genome sequences from different fungal groups—currently 18 hemiascomycetes, 8 euascomycetes and 4 basidiomycetes—enables us to gain a broad perspective on genome evolution. The sequenced genomes span a continuum of divergence levels ranging from multiple individuals within a species to species pairs with low levels of protein sequence identity and no conservation of gene order. One of the most interesting emerging areas is the growing number of events such as gene losses, gene displacements and gene relocations that can be attributed to the action of natural selection.
Comparative analysis of environmental sequences: potential and challenges
Authors: Foerstner Konrad U , Mering Christian von , Bork Peer
Published: March 2006

Environmental sequencing, also dubbed metagenomics, is increasingly being used to obtain insights into organismal communities in diverse habitats, and has a variety of potential applications foreseeable in biotechnology and medicine. The first public large-scale data provide already a wealth of information hidden in vast amounts of fragmented pieces of DNA from unknown species residing in these environments. Comparative sequence analysis is essential for the interpretation of such data. However, different layers of complexity that are intrinsic to each sample require the establishment of some baselines for comparison: how to normalize for the differences in phylogenetic and functional diversity, how to avoid biases from incomplete data, and how to deal with differences in species dominance or genome sizes? Here we discuss a few of these items and delineate some simple discriminative sequence properties for four distinct habitats.
Telomeric heterochromatin boundaries require NuA4-dependent acetylation of histone variant H2A.Z in Saccharomycescerevisiae
Authors: Babiarz Joshua E. , Halley Jeffrey E. , Rine Jasper
Published: March 2006

SWR1-Com, which is responsible for depositing H2A.Z into chromatin, shares four subunits with the NuA4 histone acetyltransferase complex. This overlap in composition led us to test whether H2A.Z was a substrate of NuA4 in vitro and in vivo. The N-terminal tail of H2A.Z was acetylated in vivo at multiple sites by a combination of NuA4 and SAGA. H2A.Z acetylation was also dependent on SWR1-Com, causing H2A.Z to be efficiently acetylated only when incorporated in chromatin. Unacetylatable H2A.Z mutants were, like wild-type H2A.Z, enriched at heterochromatin boundaries, but were unable to block spreading of heterochromatin. A mutant version of H2A.Z that could not be acetylated, in combination with a mutation in a nonessential gene in the NuA4 complex, caused a pronounced decrease in growth rate. This H2A.Z mutation was lethal in combination with a mutant version of histone H4 that could not be acetylated by NuA4. Taken together, these results show a role for H2A.Z acetylation in restricting silent chromatin, and reveal that acetylation of H2A.Z and H4 can contribute to a common function essential to life.
Dynamic homology and the likelihood criterion
Authors: Wheeler Ward C.
Published: March 2006

The use of likelihood as an optimality criterion is explored in the context of dynamic homology. Simple models and procedures are described to allow the analysis of large variable length sequence data sets, alone and in combination with qualitative information (such as morphology). Several approaches are discussed that have different likelihood interpretations in terms of maximum parsimony likelihood and maximum average likelihood. Implementation is discussed and an example in arthropod systematics presented. Topological congruence comparisons with parsimony are made.

© The Willi Hennig Society 2006.
Patterns of macroinvertebrate traits along three glacial stream continuums
Authors: ILG CHRISTIANE , CASTELLA EMMANUEL
Published: March 2006

1. Glacier‐fed streams are characterised by low spatial but high temporal heterogeneity, manifested in seasonal and diurnal discharge and suspended sediment peaks induced by glacial runoff. These streams shelter macroinvertebrate communities adapted to such harsh environmental conditions. Studies relating macroinvertebrate traits to environmental conditions in glacial streams could provide important insights into the structure and function of glacial stream communities.

2. From data collected in three glacial streams from the central Swiss and southern French Alps, we analysed the relationships among six biological traits to define five groups of macroinvertebrate taxa with similar suites of traits.

3. The longitudinal distribution of the five groups and of individual traits was analysed, as well as their variation according to a glaciality index combining water temperature, conductivity, suspended solids and substrate stability.

4. The trait diversity along the three streams showed a strong upstream‐downstream gradient. The upper reaches were dominated by a single group of taxa characterised by small, crawling, deposit feeders. The other trait‐based groups appeared progressively downstream.

5. Changes in the relative frequency of trait‐based groups along the glaciality gradient highlighted the dominance of all‐rounder resistant/resilient traits in the three streams and confirmed that environmental conditions in the glacial streams are too harsh or uniform to allow macroinvertebrate communities to develop alternative suites of traits. The findings are discussed in relation to the question of trait coding in the available literature.
Size‐ and temperature‐independence of minimum life‐supporting metabolic rates
Authors: MAKARIEVA A. M. , GORSHKOV V. G. , LI B.‐L. , CHOWN S. L.
Published: March 2006

Mass‐specific metabolic rates of 173 animal species under various conditions of prolonged food deprivation (aestivation, hibernation, sit‐and‐wait existence) and/or living at temperatures near the freezing point of water were analysed.

These minimum life‐supporting metabolic rates are independent of body mass over a nearly 80‐million‐fold body mass range and independent of temperature over a range of −1·7 to 30 °C, with a mean value of 0·1 W kg−1 and 95% CI from 0·02 to 0·67 W kg−1.

Additionally, 66 measurements of anoxic metabolic rates in 32 species capable of surviving at least 1 h of anoxia were analysed. While similarly mass‐independent, anoxic metabolic rates are significantly more widely scattered (1200‐fold 95% CI); they are on average one order of magnitude lower than during normoxia and depend on temperature with Q10 = 2·8.

Energy losses at the time of 50% mortality during anoxia are 30–300 times smaller than the energy losses tolerated by normoxic organisms in the various energy‐saving regimes studied.

These principal differences form the basis for proposing two alternative strategies by which organisms survive environmental stress: the regime of abandoned metabolic control (‘slow death’), when, as in anoxic obligate aerobes, measured rates of energy dissipation can predominantly reflect chaotic processes of tissue degradation rather than meaningful biochemical reactions; and the regime of minimum metabolic control, when biochemical order is sustained at the expense of ordered metabolic reactions. Death or survival in the regime of abandoned metabolic control is dictated by the amount of accumulated biochemical damage and not by the available energy resources, as it is in the regime of minimum metabolic control.
Extrafloral nectar from cotton (Gossypium hirsutum) as a food source for parasitic wasps
Authors: RÖSE U. S. R. , LEWIS J. , TUMLINSON J. H.
Published: March 2006

For many adult nectar‐feeding parasitoids food and moisture are essential for survival in the field. Early in the season, when floral nectar is not yet available in cotton, extrafloral nectar (EFN) is already present on young cotton plants.

The parasitoidMicroplitis croceipes(Cresson) can use EFN cotton plants as an only food source. The longevity and reproduction of EFN‐fed female wasps was comparable to wasps fed with honey and water provided on nectariless (NL) cotton plants, and was significantly higher compared with wasps kept on NL plants with no additional food source.

Wasps that were given preflight experiences on EFN cotton plants choose EFN cotton over NL cotton plants in two choice experiments in the flight tunnel. The parasitoids are more willing to search on an EFN plant at their second and third encounter with a plant previously visited, compared with an NL cotton plant.

Wasps can locate EFN from short distances by its odour alone, and find it almost as fast as honey, but much faster than odourless sucrose, which is only found randomly. Experience with EFN increased the retention ability of parasitoids on a flower model.
Scaling of mass and morphology in plants with minimal branching: an extension of the WBE model
Authors: PRICE C. A. , ENQUIST B. J.
Published: March 2006

Understanding the general principles governing the impressive diversity of plant morphology has long been a goal of botanists. However, the broad variability of plant growth forms has challenged the development of general models of plant growth.

A recent theoretical model, the fractal branching model of West, Brown and Enquist (WBE), purports to explain the scaling of plant form in a variety of taxa; however, its applicability to clades that do not meet its underlying assumptions, particularly plants that lack volume‐filling branching, has been unclear.

Here we show how an extension of the WBE model, the minimal branching model, can quantitatively predict the scaling of form in plants lacking volume‐filling branching. We then test the model's predictions with data from a biometric database on Sonoran Desert plants.

As predicted, empirical data support the ubiquity of the 3/4‐power scaling of photosynthetic surface area in plants, but nevertheless show that the morphological dimensions (height, spread) in plants with minimal branching scale with exponents differently from those in plants with fractal‐like external branching.

We then compare expectations under the minimal branching model with those of geometric similitude and fractal branching models, which make predictions that are close to those of the minimal model. Confidence intervals for empirical data sometimes include all three models. However, unanimous agreement in interspecific cases, and greater support in intraspecific cases, appear to favour the minimal model.

It is generally thought that succulents, particularly cacti, exhibit morphological adaptations that limit water loss via surface areas while increasing the capacity for water storage. Our model and supporting empirical data strongly suggest that the succulent morphology has evolved from selection to minimize external branching but not necessarily the scaling of external surface areas.

Our work demonstrates that a common body of allometric theory, based on the scaling of resource‐exchange networks, provides a theoretical baseline that can account for much diversity in land plant form and architecture.
Vulnerability of African mammals to anthropogenic climate change under conservative land transformation assumptions
Authors: THUILLER WILFRIED , BROENNIMANN OLIVIER , HUGHES GREG , ALKEMADE J. ROBERT M. , MIDGLEY GUY. F. , CORSI FABIO
Published: March 2006

Recent observations show that human‐induced climate change (CC) and land transformation (LT) are threatening wildlife globally. Thus, there is a need to assess the sensitivity of wildlife on large spatial scales and evaluate whether national parks (NPs), a key conservation tools used to protect species, will meet their mandate under future CC and LT conditions. Here, we assess the sensitivity of 277 mammals at African scale to CC at 10′ resolution, using static LT assumptions in a ‘first‐cut’ estimate, in the absence of credible future LT trends. We examine the relationship between species' current distribution and macroclimatic variables using generalized additive models, and include LT indirectly as a filter. Future projections are derived using two CC scenarios (for 2050 and 2080) to estimate the spatial patterns of loss and gain in species richness that might ultimately result. We then apply the IUCN Red List criteria A3(c) of potential range loss to evaluate species sensitivity. We finally estimate the sensitivity of 141 NPs in terms of both species richness and turnover. Assuming no spread of species, 10–15% of the species are projected to fall within the critically endangered or extinct categories by 2050 and between 25% and 40% by 2080. Assuming unlimited species spread, less extreme results show proportions dropping to approximately 10–20% by 2080. Spatial patterns of richness loss and gain show contrasting latitudinal patterns with a westward range shift of species around the species‐rich equatorial zone in central Africa, and an eastward shift in southern Africa, mainly because of latitudinal aridity gradients across these ecological transition zones. Xeric shrubland NPs may face significant richness losses not compensated by species influxes. Other NPs might expect substantial losses and influxes of species. On balance, the NPs might ultimately realize a substantial shift in the mammalian species composition of a magnitude unprecedented in recent geological time. To conclude, the effects of global CC and LT on wildlife communities may be most noticeable not as a loss of species from their current ranges, but instead as a fundamental change in community composition.
Measurement and restoration of the point spread function of fluorescence confocal microscopy
Authors: YOO H. , SONG I. , GWEON D.‐G.
Published: March 2006

The point spread function of an objective lens of a fluorescence confocal microscope was directly measured by imaging fluorescent beads. We analysed how the measurement of the point spread function was influenced by the diameter of the fluorescent beads and how the restoration technique with a deconvolution algorithm improved the measuring performance. Numerical and experimental results are presented for a typical point spread function and a zero‐centred point spread function.
Cognitive behaviour therapy and people with learning disabilities: implications for developing nursing practice
Authors: BROWN M. , MARSHALL K.
Published: March 2006

People with learning disabilities are an ageing and increasing population and have been the subject of policy initiatives by the four countries of the UK, detailing the range of supports that need to be in place for this group. The evidence base of their mental health needs is growing and with it the need to ensure the full range of psychotherapies available to the general population are made available to people with learning disabilities. Cognitive Behaviour Therapy (CBT) is now a widely accepted and effective form of psychotherapy for many mental health problems and the evidence base is growing on the effectiveness with the learning disability population; however, the model needs to be applied differently for this group to take account of their cognitive impairment and support needs. Registered Nurses in Learning Disabilities are well placed to apply this approach within their clinical practice; however, there is an absence of leadership and direction in the development of CBT for this group of clinicians. There is a need to support education and practice development to contribute to addressing the emotional needs of people with learning disabilities. Action is required to support education to prepare Registered Nurses in Learning Disabilities to practice CBT and to contribute to the ongoing development of research in this area of clinical practice.
Molecular variation, systematics and distribution of the Anopheles fluviatilis complex in southern Asia
Authors: Chen B. , Butlin R. K. , Pedro P. M. , Wang X. Z. , Harbach R. E.
Published: March 2006

Abstract.  Species of the Anopheles fluviatilis James and Anopheles minimus complexes (Diptera: Culicidae) are difficult to distinguish morphologically. Members of the two complexes have been confused and, consequently, their distributions and roles in malaria transmission are uncertain. We identified numerous mosquitoes from China, Thailand, Vietnam, India, Nepal, Pakistan and Iran by single‐strand conformation polymorphism (SSCP) and/or sequencing, and analysed the variation in the 28S D3 region of ribosomal DNA for members of the Minimus Subgroup and also the internal transcribed spacer region 2 (ITS2) for members of the An. fluviatilis complex. The D3 region is highly conserved between taxa and therefore could serve as a standard for molecular diagnosis of the subgroup members. D3 sequence, bionomics and malaria transmission data provide further evidence that An. fluviatilis S in India is conspecific with An. minimus C in South‐east Asia. An. fluviatilis T has three ITS2 haplotypes (designated T1, T2 and Y) and its distribution in India, Nepal, Pakistan and Iran is confirmed. An. fluviatilis U is well defined on cytogenetic grounds in Uttar Pradesh, India, but is very close to An. fluviatilis T and the two species may hybridize in some regions. Variant ITS2 sequences suggest the possible existence of two additional taxa within the An. fluviatilis complex, one in Iran and another in India, provisionally designated An. fluviatilis forms V and X, respectively. The distributions of members of the An. fluviatilis and An. minimus complexes in south‐central Asia are summarized.
Guide to blackflies of the Simulium damnosum complex in eastern and southern Africa
Authors: Krueger A.
Published: March 2006

Abstract.  At least 26 members of the Simulium damnosum Theobald complex (Diptera: Simuliidae) are known from eastern Africa, most of which are assumed to be non‐anthropophilic and some are restricted to small areas of endemicity. Their discovery was based on polytene chromosome inversion polymorphisms and since then they have been cited as cytological entities, but, in many cases, with inadequate descriptions (e.g. without illustrations of the chromosomes). The present distribution, taxonomy and vector identity have been re‐evaluated during the last decade in conjunction with ongoing onchocerciasis control programmes. Here, a summary of the relevant data is presented, integrating results of cytotaxonomic, morphotaxonomic and molecular investigations into a guide that provides a comprehensive system of identification for the cytoforms ‘Kagera’, ‘Kasyabone’, ‘Kibwezi’, ‘Kisiwani’, ‘Kisiwani E’, ‘Kulfo’, ‘Linthipe’, ‘Mombo’, ‘Mutonga’, ‘Njombe’, ‘Nkusi’, ‘Nkusi SA’, ‘Nkusi SW’, ‘Nyika’, ‘Pienaars’, ‘Sanje’, ‘Sebwe’, ‘Turiani’, Simulium damnosum sensu stricto, Simulium kaffaense Hadis et al., Simulium kilibanum Gouteux, Simulium kipengere Krueger, Simulium latipollex (Enderlein), Simulium pandanophilum Krüger, Nurmi & Garms, Simulium plumbeum Krueger, Simulium thyolense Vajime et al. and for five newly recognized molecular forms of ‘Nkusi’ and S. kilibanum. All taxa except S. pandanophilum are assigned to one of five subcomplexes (damnosum, Ketaketa, Kibwezi, Sanje, squamosum) within the S. damnosum complex. The guide encompasses anthropophilic and non‐anthropophilic segregates for the whole of eastern and southern Africa, and is not restricted to larval chromosome criteria; in many cases it also allows the typing of adult flies.
Behavioural responses of dairy cattle to the stable fly, Stomoxys calcitrans, in an open field environment
Authors: Mullens B. A. , Lii K.‐S. , Mao Y. , Meyer J. A. , Peterson N. G. , Szijj C. E.
Published: March 2006

Abstract.  Individual cows (25 in each of four herds) were monitored 8–10 times weekly for 12 weeks (stable fly season) on a southern California dairy, with 100 observations per cow. The numbers of biting stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae) on the front legs and the frequencies of four fly‐repelling behaviours per 2‐min observation period [head throws, front leg stamps, skin twitches (panniculus reflex) and tail flicks] were recorded. Fly numbers varied, peaking at 3.0–3.5 flies per leg in week 9 (late May). Weekly herd mean frequencies of fly‐repelling behaviours were highly dependent on fly numbers, with a linear regression r2 > 0.8. Head throws and stamps were less frequent than skin twitches and tail flicks. Individual cows differed in numbers of stable flies and behaviours. Behaviours were correlated with flies for individual cows, but at a lower level than were herd means (r = 0.3–0.7). Cows that stamped more within a herd tended to have lower fly counts; other fly‐repelling behaviours were less effective. Cows maintained ranks within a herd with regard to fly numbers (r = 0.47), head throws (0.48), leg stamps (0.64), skin twitches (0.69) and tail flicks (0.64). Older cows tended to harbour higher fly numbers and to stamp less relative to younger adult cows. Ratios of leg stamps and head throws to fly numbers dropped significantly through time, suggesting habituation to pain associated with fly biting. Tail flicks were not effective for repelling Stomoxys, but were easiest to quantify and may help in monitoring pest intensity. At this low–moderate fly pressure, no consistent impacts on milk yield were detected, but methods incorporating cow behaviour are recommended for future studies of economic impact.
Co‐occurrence of East and West African kdr mutations suggests high levels of resistance to pyrethroid insecticides in Anopheles gambiae from Libreville, Gabon
Authors: Pinto J. , Lynd A. , Elissa N. , Donnelly M. J. , Costa C. , Gentile G. , Caccone A. , Rosário V. E. DO
Published: March 2006

Abstract.  Point mutations in the voltage‐gated sodium channel gene involved in knockdown resistance to DDT and pyrethroid insecticides have been described in several insect species. In the malaria vector Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) two mutations have been identified. The first, consisting of a leucine–phenylalanine substitution at amino acid position 1014, is widespread in West Africa. The second, a leucine–serine substitution at the same position, has to date only been detected in western Kenya. Analysis of the kdr polymorphism in a sample of 106 An. gambiae s.s. of the rDNA S‐form/Type I collected in Libreville (Gabon) surprisingly revealed the presence of both East and West African kdr mutations with frequencies of 63% and 37%, respectively. No wild‐type alleles were detected and there was an excess of heterozygous genotypes (P = 0.04). In addition, an inconsistency was found during the kdr genotyping procedures by polymerase chain reaction, which could have lead to an underestimation of resistance alleles. The implications of these findings are discussed.
Comparison of plume structures of carbon dioxide emitted from different mosquito traps
Authors: Cooperband Miriam F. , Cardé Ring T.
Published: March 2006

Abstract. A large field wind tunnel was used to compare four types of CO2‐baited mosquito traps. This study compared the plume structure and concentration of CO2emitted by each trap, flow of suction into the trapping systems, flow of CO2being released, trap shape and configuration, differences in visual appearance, and differences in temperature and humidity of emissions at the source of CO2compared to ambient air. The structure of the CO2plumes emitted by each trap differed considerably. All four plumes were turbulent, causing the concentration of CO2within several metres of the source to attenuate to between 375 and 875 p.p.m. The Encephalitis Virus Surveillance (EVS) trap emitted concentrations of CO2exceeding 20 000 p.p.m., the detection limits of our equipment, whereas the Mosquito Magnet®Freedom (MMF), Mosquito Magnet®Liberty (MML) and Mosquito Magnet®X (MMX) traps released CO2at peaks of about 3500, 7200 and 8700 p.p.m., respectively. The MMX trap produced the greatest air velocity at both the suction inlet and CO2outlet, followed by the MMF, MML and the EVS traps, respectively.
Thrust front segmentation induced by differential slab retreat in the Apennines (Italy)
Authors: Scrocca Davide
Published: March 2006

New seismic reflection data reveal that the south‐eastward prolongation of the Apennine thrust front in the central Adriatic Sea is most likely located in a more external position with respect to the traditional interpretation. In this new interpretation, the Apennine thrust front shows a segmented geometry in correspondence to the Tremiti lithospheric transfer zone. The available data suggest that the north‐eastward flexural retreat of the subducting Adriatic lithosphere and the related frontal accretion of the Apennine accretionary prism have acted during the last 5 Ma and may be considered still lively in both the Po plain and in the Central Adriatic domain, north of the Tremiti lineament. By analysing the tectonic evolution of the Apulo‐Adriatic areas, it may be argued that the differential slab retreat between the central and southern sectors of the subducting Adriatic plate has been able to induce the segmentation of the Apennine thrust front.
Biolistic delivery of Ca2+ dyes into plant and algal cells
Authors: Bothwell John H.F. , Brownlee Colin , Hetherington Alistair M. , Ng Carl K.‐Y. , Wheeler Glen L. , McAinsh Martin R.
Published: March 2006

In eukaryotes, changes in cytosolic Ca2+ concentrations ([Ca2+]cyt) are associated with a number of environmental and developmental stimuli. However, measuring [Ca2+]cyt changes in single plant or algal cells is often problematic. Although a wide range of Ca2+‐sensitive fluorescent dyes is available, they are often difficult to introduce into plant cells. Micro‐injection is the most robust method for dye loading, but is time‐consuming, technically demanding, and unsuitable in many cell types. To overcome these problems, we have adapted biolistic techniques to load Ca2+‐sensitive dyes into guard cells of the flowering plant, Commelina communis, cells of the green alga Chlamydomonas reinhardtii, and zygotes of the brown alga, Fucus serratus. Using this approach, we have been able to monitor [Ca2+]cyt changes in response to various stimuli, including a novel [Ca2+]cyt response in C. reinhardtii. The method allows the use of free acid and dextran‐conjugated dyes. Biolistic loading of differentiated plant cells is easier, quicker, and more widely applicable than micro‐injection, and should broaden the study of plant signal transduction.
An Arabidopsis cell wall‐associated kinase required for invertase activity and cell growth
Authors: Kohorn Bruce D. , Kobayashi Masaru , Johansen Sue , Riese Jeff , Huang Li‐Fen , Koch Karen , Fu Sarita , Dotson Anjali , Byers Nicole
Published: March 2006

The wall‐associated kinases (WAK), a family of five proteins that contain extracellular domains that can be linked to pectin molecules of the cell wall, span the plasma membrane and have a cytoplasmic serine/threonine kinase domain. Previous work has shown that a reduction in WAK protein levels leads to a loss of cell expansion, indicating that these receptor‐like proteins have a role in cell shape formation. Here it is shown that a single wak2 mutation exhibits a dependence on sugars and salts for seedling growth. This mutation also reduces the expression and activity of vacuolar invertase, often a key factor in turgor and expansion. WAKs may thus provide a molecular mechanism linking cell wall sensing (via pectin attachment) to regulation of solute metabolism, which in turn is known to be involved in turgor maintenance in growing cells.
Use of the glucosyltransferase UGT71B6 to disturb abscisic acid homeostasis in Arabidopsis thaliana
Authors: Priest David M. , Ambrose Stephen J. , Vaistij Fabián E. , Elias Luisa , Higgins Gillian S. , Ross Andrew R. S. , Abrams Suzanne R. , Bowles Dianna J.
Published: March 2006

A glucosyltransferase (GT) of Arabidopsis, UGT71B6, recognizing the naturally occurring enantiomer of abscisic acid (ABA) in vitro, has been used to disturb ABA homeostasis in planta. Transgenic plants constitutively overexpressing UGT71B6 (71B6‐OE) have been analysed for changes in ABA and the related ABA metabolites abscisic acid glucose ester (ABA‐GE), phaseic acid (PA), dihydrophaseic acid (DPA), 7′‐hydroxyABA and neo‐phaseic acid. Overexpression of the GT led to massive accumulation of ABA‐GE and reduced levels of the oxidative metabolites PA and DPA, but had marginal effect on levels of free ABA. The control of ABA homeostasis, as reflected in levels of the different metabolites, differed in the 71B6‐OEs whether the plants were grown under standard conditions or subjected to wilt stress. The impact of increased glucosylation of ABA on ABA‐related phenotypes has also been assessed. Increased glucosylation of ABA led to phenotypic changes in post‐germinative growth. The use of two structural analogues of ABA, known to have biological activity but to differ in their capacity to act as substrates for 71B6 in vitro, confirmed that the phenotypic changes arose specifically from the increased glucosylation caused by overexpression of 71B6. The phenotype and profile of ABA and related metabolites in a knockout line of 71B6, relative to wild type, has been assessed during Arabidopsis development and following stress treatments. The lack of major changes in these parameters is discussed in the context of functional redundancy of the multigene family of GTs in Arabidopsis.
Beta diversity of tropical marine benthic assemblages in the Spermonde Archipelago, Indonesia
Authors: Becking Leontine E. , Cleary Daniel F. R. , de Voogd Nicole J. , Renema Willem , de Beer Manon , van Soest Rob W. M. , Hoeksema Bert W.
Published: March 2006

In order to preserve diversity it is essential to understand how assemblages change across space. Despite this fact, we still know very little about how marine diversity is spatially distributed, especially among lesser‐studied invertebrate taxa. In the present study beta‐diversity patterns of sea urchins, sponges, mushroom corals and larger foraminifera were assessed in the Spermonde Archipelago (Indonesia). Using ordinations we showed that the inshore zone (<5 km offshore), midshore zone (5 < x < 30 km offshore) and distance offshore zone (>30 km offshore) all contained distinct assemblages of sponges and corals, while only foraminifera assemblages from the inshore (<5 km offshore) zone were distinct. There was a significant spatial pattern of community similarity for all taxa surveyed, but this pattern proved to be wholly related to environmental variables for sponges and foraminifera, and primarily for mushroom corals and sea urchins. The lack of a pure spatial component suggests that these taxa may not be dispersal limited within the spatial scales of this study (c. 1600 km2). The analyses of the corals and foraminifera were additionally tested at two spatial scales of sampling. Both taxa were primarily associated with local‐scale environmental variables at the local scale and larger‐scale variables at the larger scale. Mean inter‐plot similarity was also higher and variation lower at the larger scale. The results suggest that substantial variation in similarity can be predicted using simple locally assessed environmental variables combined with remotely sensed parameters.
Sharksucker–shark interaction in two carcharhinid species
Authors: Brunnschweiler Juerg M.
Published: March 2006

It is not known whether sharksuckers have positive or negative effects on their hosts, partly because this association is difficult to study in free‐ranging fish. I observed the behaviour of sharks with and without sharksuckers, to determine whether the hosts actively avoid sharksuckers. Wild blacktip sharks, Carcharhinus limbatus, took evasive actions when sharksuckers, Echeneis naucrates, attached to them, presumably to escape from skin irritation or hydrodynamical drag caused by the sharksuckers. Sharksuckers were most often attached to the belly or back of the shark, and sharks reacted most strongly to sharksuckers on their heads, sides, and dorsal fins. Observations of two captive bull sharks, Carcharhinus leucas, indicated that swimming speed increased when sharksuckers were attached. This paper supports the hypothesis that sharksucker attachment irritates sharks, and that the relationship between the two is best viewed as a subtle host–parasite interaction.
ENSO as a natural experiment to understand environmental control of meiofaunal community structure
Authors: Sellanes Javier , Neira Carlos
Published: March 2006

The sediments of the Bay of Concepción and the adjacent shelf underlie one of the most productive upwelling areas in the SE Pacific margin. Reports on factors controlling meiofaunal community structure in these kinds of organic‐rich and oxygen‐deficient habitats are scarce in the literature. In this study, five sites along a transect from the mid‐Bay of Concepción (27 m) to the outer shelf (120 m) were studied on fives dates (May, August, November 1997, and March and May 1998) in order to assess the dynamic relationships between sedimentary organic matter and metazoan meiofauna. The sampling period coincided with the 1997–1998 El Niño event. Sediment parameters investigated were the redox potential discontinuity depth, photosynthetic pigment concentrations (chlorophyll a and phaeopigments), organic carbon, nitrogen, total lipids, carbohydrates, and proteins. In general, lowest values of meiofauna abundance and biomass were found within the naturally eutrophic Bay of Concepción and towards the shelf break, while maximum values occurred at intermediate depths. During the whole period, the meiofaunal abundance was negatively correlated with the concentration of most of the biochemical components of organic matter, as well as with the sediment phaeopigment content. However, positive correlations were found with chlorophyll a derived indices and with bottom‐water oxygen content. Most of the sediment parameters displayed a seasonal cycle, but towards the beginning of 1998, an effect of the 1997–1998 El Niño was evident. Typical austral‐summer (i.e. oxygen‐deficient) conditions did not develop, and sedimentary parameters reflected a decreased input of phytodetritus. Along the transect, the magnitude of this effect on meiofauna varied among sites. An overall positive response, in terms of meiofaunal abundance was observed, probably due to the amelioration of low oxygen conditions in the sediment.
Distribution of macrobenthic assemblages along a marine gradient in Mediterranean eutrophic coastal lagoons
Authors: Rossi Francesco , Castelli Alberto , Lardicci Claudio
Published: March 2006

Coastal lagoons can be characterised by strong environmental changes along the outer marine‐inner brackish gradient, which are reflected in the patterns of distribution of organisms and composition of assemblages. Close to the sea the assemblages are dominated by marine animals, while in the innermost confined areas, there would be estuarine taxa and organisms typical of organically‐enriched areas. During the last decades, human impact has been severe in these habitats and has often profoundly altered the distribution of animals and plants along the gradient. In this study we have analysed the distribution of macrofauna along the outer marine‐inner brackish gradient in five Italian lagoons, affected by severe human disturbance on the Adriatic, Tyrrhenian and Sardinian coasts. We aimed to measure changes in the composition of assemblages according to the distance from the sea, consistent among lagoons and time, after the occurrence of eutrophication, repeated distrophic crisis and other human interventions. We considered existing data from campaigns done during 1994, 1995 and 1999. We arranged different datasets according to the available data, in order to measure the spatial distribution of macrofauna genera with distance from the sea and through time. Analyses showed differences among assemblages related to the gradient. Nevertheless, the species characterizing the assemblages were all typical of organically‐enriched areas, which testified to an impoverishment of diversity and functioning of all these systems.
Regional patterns of microsatellite diversity in Ethiopian tetraploid wheat accessions
Authors: Yifru T. , Hammer K. , Huang X. Q. , Röder M. S.
Published: March 2006

This study was conducted to assess regional patterns of diversity of Ethiopian tetraploid wheat accessions and to identify areas of diversity that can be used as source of new germplasm for developing high yielding and stable varieties. A collection of 133 Ethiopian tetraploid wheat accessions and eight introduced cultivars was analysed using 29 wheat microsatellite markers. A total of 383 alleles were detected with an average value of 13.14 alleles per locus. Relatively more alleles were observed in the B genome than in the A genome. Gene diversity indices ranged from 0.08 to 0.95, with a mean value of 0.72. Accessions collected from the same region were pooled and the number of alleles and gene diversity were calculated over the 29 simple sequence repeats for each region. Higher numbers of alleles were detected in the Shewa region (8.72), followed by Tigray (5.86) and Hararghe (5.76). The highest average gene diversity value was found in Shewa (0.65), followed by Gondar (0.64). No significant correlation was observed between geographic distance and genetic distance. Out of 383 different alleles detected, 93 (24.4%) were observed to be region‐specific. Region‐specific alleles were found across all chromosomes except for Xgwm752, Xgwm155 and Xgwm148. Genetic similarity coefficients were estimated for all the possible 55 pairs of regional comparisons and they ranged from 0.16 to 0.52, with a mean value of 0.50. All provinces were differentiated in the UPGMA cluster diagram.
Approaches for field assessment of resistance to leaf pathogens in spring barley varieties
Authors: Pinnschmidt H. O. , Hovmøller M. S. , ØStergård H.
Published: March 2006

The resistance of spring barley varieties to powdery mildew, leaf rust, leaf scald and net blotch was characterized by using results from inoculated small‐plot nurseries and larger survey plots subject to natural infection. The experiments were conducted in different environments. Both trial types often yielded complementary results with respect to the ranking of varieties suggesting that a recommended variety characterization should include both naturally infected survey‐type trials and nursery trials in which the most relevant pathogen isolates and/or isolate mixtures or populations are used for inoculation. Average and median values of the diseased leaf area of a variety were highly correlated with each other and with the ‘genotype main effect’ determined by joint regression analysis, whereas maximum diseased leaf area was poorly correlated with them. Statistics based on absolute disease severity values were highly correlated with the corresponding statistics derived from relative values. It is suggested that one should use at least two parameters to characterize the disease resistance of a variety, a parameter indicating the overall resistance level and a parameter indicating the potential susceptibility and/or resistance instability of a variety. For practical purposes, the genotype median and maximum, respectively, may represent these, although statistically more appropriate parameters do exist.
Identification of wheat–Thinopyrum intermedium 2Ai‐2 ditelosomic addition and substitution lines with resistance to barley yellow dwarf virus
Authors: Lin Z. S. , Huang D. H. , Du L. P. , Ye X. G. , Xin Z. Y.
Published: March 2006

Among the regenerated plants derived from immature hybrid embryos of wheat–Thinopyrum intermedium disomic addition line Z6 × common wheat variety ‘Zhong8601’, a plant with a telocentric chromosome and barley yellow dwarf virus (BYDV) resistance was obtained. The telocentric chromosome paired with an entire Thinopyrum chromosome to form a heteromorphic bivalent at meiotic metaphase I. Genomic in situ hybridization showed that the telosome originated from Th. intermedium. Two ditelosomic additions and one disomic substitution were identified among the offspring of the plant. Two random amplified polymorphic DNA molecular markers were identified among 150 random primers used to detect the different arms of the alien chromosome. These might be useful for developing translocation lines with BYDV resistance.