bluuebunny/crossref_metadata_2025 huggingface dataset:
Dispersal of black sea bass (Centropristis striata) larvae on the southeast U.S. continental shelf: results of a coupled vertical larval behavior – 3D circulation model
Authors: EDWARDS K. P. , HARE J. A. , WERNER F. E.
Published: July 2008

In the marine environment, pelagic dispersal is important for determining the distribution and abundance of populations, as well as providing connections among populations. Estimates of larval dispersal from spawning grounds are important to determining temporal and spatial patterns in recruitment that may have significant influences on the dynamics of the population. We present a case study of the dispersal of Centropristis striata (black sea bass) larvae on the southeast U.S. continental shelf. We use a coupled larval behavior – 3D circulation model to compare the effects of the timing and location of spawning against that of larval vertical migration on larval dispersal. Using the results of field data on larval vertical distributions, we compare the dispersal of virtual ‘larvae’ which have ontogenetic changes in vertical behavior with that of particles fixed near the surface and near the bottom. Larvae were released at potential spawning sites four times throughout the spawning season (February through May) for 3 yr (2002–04) and tracked for the assumed larval duration (from 27 to 37 days including the egg stage). Results indicate that adult behavior, in the form of spawning time and location, may be more important than larval vertical behavior in determining larval dispersal on the inner‐ and mid‐ continental shelves of this region.
Tuning in to multiple predators: conflicting demands for shell morphology in a freshwater snail
Authors: LAKOWITZ THOMAS , BRÖNMARK CHRISTER , NYSTRÖM PER
Published: July 2008

1. We examined the response to chemical cues from fish and crayfish, two predators with contrasting feeding modes, and their single and combined effect on shell morphology in the freshwater snail Radix balthica.

2. Snails were subjected to four treatments: tench (Tinca tinca), signal crayfish (Pacifastacus leniusculus), a combination of tench and signal crayfish and no predators (control). Shell shape, crushing resistance and shell thickness were quantified. We also analysed whether shape or shell thickness contributes most to crushing resistance.

3. Chemical cues from the fish induced a rounder shell shape in R. balthica, a thicker shell and a higher crushing resistance, whereas crayfish chemical cues had no effect on shell morphology, shell thickness or crushing resistance. Shell shape contributed more to crushing resistance than shell thickness.

4. The combined predator treatment showed an intermediate response between the fish and crayfish treatments. Shell roundness was reduced compared with the fish treatment, but the reduced crushing resistance that comes with a less rounded shell was compensated by an increased investment in extra shell material, exceeding that of the fish treatment.

5. Our study extends previous studies of multipredator effects on phenotypically plastic freshwater snails by showing that the snails are able to fine‐tune different elements of morphology to counter predator‐specific foraging modes.
Testing Gassmann fluid substitution: sonic logs versus ultrasonic core measurements
Authors: Grochau Marcos , Gurevich Boris
Published: July 2008

Although Gassmann fluid substitution is standard practice for time‐lapse studies, its validity in the field environment rests upon a number of underlying assumptions. The impact of violation on the predictions of Gassmann equations can only ultimately be validated by in situ testing in real geological environments. In this paper we show a workflow that we developed to test Gassmann fluid substitution by comparing saturated P‐wave moduli computed from dry core measurements against those obtained from sonic and density logs. The workflow has been tested on 43 samples taken from a 45 m turbidite reservoir from the Campos Basin, offshore Brazil. The results show good statistical agreement between the P‐wave elastic moduli computed from cores using the Gassmann equation with the corresponding moduli computed from log data. This confirms that all the assumptions of the Gassmann are adequate within the measurement error and natural variability of elastic properties. These results provide further justification for using the Gassmann theory to interpret time‐lapse effects in this sandstone reservoir and in similar geological formations.
Dry matter production, nutritive value and efficiency of nutrient utilization of a complementary forage rotation compared to a grass pasture system
Authors: Garcia S. C. , Fulkerson W. J. , Brookes S. U.
Published: July 2008

In pasture‐based dairy farming, new sustainable systems that involve the annual dry matter (DM) production of grazed and conserved forage beyond the potential of grazed pasture alone are being sought. The objective of this experiment conducted in Australia was to compare a complementary forage rotation (CFR) for conservation and grazing, comprising an annual sequence of three crops, namely maize (Zea mays L), forage rape (Brassica napus L) and a legume (Persian clover, Trifolium repesinatum L or maple pea, Pisum sativum L), with a pasture [kikuyu grass (Pennisetum clandestinum) over‐sown with short‐rotation ryegrass (Lolium multiflorum L)] as a pasture control treatment. The experiment was a complete randomized block design with four replicates (∼0·7 ha each). Annual dry‐matter (DM) yield over the 3 years averaged >42 t ha−1 year−1 for the CFR treatment and >17 t ha−1 year−1 for the pasture treatment. The high DM yield of the CFR treatment resulted from >27 t ha−1 year−1 from maize harvested for silage and >15 t DM ha−1 year−1 utilized by grazing the forage rape and legumes. Total input of nitrogen (N) and water were similar for both treatments, resulting in higher N‐ and water‐use efficiency for the CFR treatment, which was more than twice that for the pasture treatment. Overall, the nutritive value of the pasture treatment was slightly higher than the mean for that of the CFR treatment. The implications of these results are that a highly productive system based on the CFR treatment in conjunction with the use of pasture is achievable. Such a dairy production system in Australia could increase the total supply of feed resources grown on‐farm and the efficiency of use of key resources such as N and water.
Endophyte infection, nutrient status of the soil and duration of snow cover influence the performance of meadow fescue in sub‐artic conditions
Authors: Wäli P. R. , Helander M. , Nissinen O. , Lehtonen P. , Saikkonen K.
Published: July 2008

Neotyphodium endophytic fungi are beneficial for certain cultivated grass species by increasing the stress tolerance and herbivore resistance of their host plants. These grass endophytes have been widely studied in temperate regions. Endophyte‐infected grasses are also cultivated in sub‐artic conditions, but studies on the effects of endophyte infection on grasses under conditions of prolonged snow cover are scarce. A 2‐year field experiment was conducted with two originally endophyte‐infected meadow fescue (Schedonorus pratensis) cultivars. The growth and reproduction of endophyte‐infected (E+) and endophyte‐free (E−) plants of two cultivars at two sites, differing in nutrient status and duration of snow cover, were compared at the latitude of the Arctic Circle in Finland. Endophyte infection enhanced plant performance most at the site with the higher nutrient status and the shorter duration of snow cover. The difference in growth between E+ and E− grasses increased during the second growing season and was most pronounced in the reproductive investment of grasses, but the benefits of endophyte infection for reproductive mass were cultivar‐dependent. At the site with the lower nutrient status, costs of endophyte infection on the vegetative growth of grasses were found. The results suggest that Neotyphodium infection may benefit meadow fescue in sub‐arctic conditions but the extent of the effects is dependent on the cultivar and the environment.
How does protein supplementation affect the selectivity and performance of Charolais cows on extensively grazed pastures in late autumn?
Authors: Farruggia A. , Dumont B. , D’hour P. , Egal D.
Published: July 2008

Management of beef cows grazing extensively grazed semi‐natural pastures in temperate regions in late autumn can require supplements to be offered. The effects of supplementation with soya bean meal on the diet selected by Charolais cows and on their subsequent performance were examined for an 8‐week period in late autumn in 2 years. Three groups of eight cows were compared: non‐supplemented dry cows (D), non‐supplemented (L) and supplemented (LS) lactating cows. The amount of soya bean meal supplement offered per cow was 250 g d−1 in year 1 and 800 g d−1 in year 2. Dietary choices were measured by direct observations and herbage intake was estimated in year 2. Supplementation affected neither diet selection (L: 0·42 vs. LS: 0·43 for the proportion of bites on green patches in year 1; 0·24 vs. 0·22 in year 2) nor daily organic matter intake of herbage (L: 15·6 vs. LS: 15·9 kg d−1), which may have resulted from an adequate crude protein concentration of herbage. The higher total dry matter intake by cows offered the supplement reduced losses in live weight (L: −1212 vs. LS: −828 g d−1; P < 0·01) rather than increased milk production (L: 5·1 vs. LS: 5·0 kg d−1). This may be linked to the low milk yield potential of the Charolais cows. The use of lactating cows rather than dry cows for pasture management in late autumn would increase the utilization of herbage but a reduction in liveweight losses of cows by supplementation is unlikely to be economic.
Identification of mutations in the F9 gene including exon deletion by multiplex ligation‐dependent probe amplification in 33 unrelated Korean patients with haemophilia B
Authors: KWON M.‐J. , YOO K.‐Y. , KIM H.‐J. , KIM S.‐H.
Published: July 2008

Summary.  Haemophilia B (HB) is a rare X‐linked recessive bleeding disorder caused by a mutation in the F9 gene. The aims of this study were to characterize the mutation spectrum of F9 in Korean patients with HB to establish the optimal molecular diagnostic strategy and to find genotype–phenotype correlations. Study subjects consisted of 33 unrelated Korean patients with HB. We performed polymerase chain reaction (PCR) amplification and direct sequencing of all exons and flanking sequences of F9. When large deletion was suspected from PCR failure, exon dosage test using multiplex ligation‐dependent probe amplification (MLPA) was performed. We identified disease‐causing mutations in 32 out of 33 patients by direct sequencing analyses (mutation detection rate, 97%). A total of 28 unique mutations were detected, including 7 novel ones. Six mutations were recurrent but observed in no more than two patients. In the remaining one patient, exon 1 was not amplified, and MLPA analysis confirmed a large deletion involving exon 1. The genotype–phenotype correlations between the type of mutation and the severity of factor deficiency were not consistent, as has been previously reported. One patient developed inhibitor, and he was the patient with exon 1 deletion. Based on our results from 33 Korean patients with HB, which showed no hotspot for mutations, direct sequencing of all exons with flanking sequences is needed as the first‐line test. MLPA can be a feasible platform at clinical laboratories to detect large deletion mutations in suspected cases.
The mannose receptor binds Trichuris muris excretory/secretory proteins but is not essential for protective immunity
Authors: DeSchoolmeester Matthew L. , Martinez‐Pomares Luisa , Gordon Siamon , Else Kathryn J.
Published: July 2008

Trichuris muris is a natural mouse model of the human gastrointestinal nematode parasite Trichuris trichiura and it is well established that a T helper type 2‐dominated immune response is required for worm expulsion. Macrophages accumulate in the large intestine of mice during infection and these cells are known to express the mannose receptor (MR), which may act as a pattern recognition receptor. The data presented here show for the first time that T. muris excretory/secretory products (E/S) induce bone‐marrow‐derived macrophages (BMDM) to produce several cytokines and have MR‐binding activity. Using alternatively activated BMDM from MR knockout mice it is shown that the production of interleukin‐6 partially depends on the MR. Infection of MR knockout mice with T. muris reveals that this receptor is not necessary for the expulsion of the parasite because MR knockout mice expel parasites with the same kinetics as wild‐type animals and have similar cytokine responses in the mesenteric lymph nodes. Furthermore, despite acting to reduce serum levels of proinflammatory mediators, absence of the MR does not lead to increased gut inflammation after T. muris infection when assessed by macrophage influx, goblet cell hyperplasia and crypt depth. This work suggests that, despite binding components of T. muris E/S, the MR is not critically involved in the generation of the immune response to this parasite.
Hepatitis B virus surface antigen impairs myeloid dendritic cell function: a possible immune escape mechanism of hepatitis B virus
Authors: Op den Brouw Marjoleine L. , Binda Rekha S. , Van Roosmalen Mark H. , Protzer Ulrike , Janssen Harry L. A. , Van Der Molen Renate G. , Woltman Andrea M.
Published: July 2008

Chronic hepatitis B virus (HBV) infection is the result of an inadequate immune response towards the virus. Myeloid dendritic cells (mDC) of patients with chronic HBV are impaired in their maturation and function, resulting in more tolerogenic rather than immunogenic responses, which may contribute to viral persistence. The mechanism responsible for altered mDC function remains unclear. The HBV‐infected patients display large amounts of HBV particles and viral proteins in their circulation, especially the surface antigen HBsAg, which allows multiple interactions between the virus, its viral proteins and DC. To assess whether HBV directly influences mDC function, the effects of HBV and HBsAg on human mDC maturation and function were investigated in vitro. As already described for internalization of HBV by DC, the present study shows that peripheral blood‐derived mDC of healthy controls also actively take up HBsAg in a time‐dependent manner. Cytokine‐induced maturation in the presence of HBV or HBsAg resulted in a significantly more tolerogenic mDC phenotype as demonstrated by a diminished up‐regulation of costimulatory molecules and a decreased T‐cell stimulatory capacity, as assessed by T‐cell proliferation and interferon‐γ production. In addition, the presence of HBV significantly reduced interleukin‐12 production by mDC. These results show that both HBV particles and purified HBsAg have an immune modulatory capacity and may directly contribute to the dysfunction of mDC in patients with chronic HBV. The direct immune regulatory effect of HBV and circulating HBsAg particles on the function of DC can be considered as part of the mechanism by which HBV escapes immunity.
Serratia entomophila inoculation causes a defect in exocytosis in Costelytra zealandica larvae
Authors: Gatehouse H. S. , Marshall S. D. G. , Simpson R. M. , Gatehouse L. N. , Jackson T. A. , Christeller J. T.
Published: July 2008

Rapid elimination of midgut luminal proteinase activity and gut clearance are the two major symptoms of amber disease in Costelytra zealandica larvae because of the three‐subunit protein toxin complex produced in Serratia entomophila and Serratia proteamaculans. Quantitative PCR analysis of mRNA from the major serine proteinase gene families showed that loss of proteinase activity did not result from transcriptional downregulation. Unexpectedly, protein levels and rates of protein synthesis increased, rather than decreased, in the midgut of diseased insects. Proteomic analysis of midgut tissues showed marked differences between healthy and diseased midguts. Large increases in soluble forms of both actin and tubulin were identified from 2D‐gels, together with concurrent decreases in the levels of polymeric actin‐associated proteins: actin depolymerizing factor and cyclophilin. These results suggest that the Serratia toxin acts to cause degradation of the cytoskeletal network and prevent secretion of midgut gut digestive proteinases as both the actin cytoskeleton and microtubules are involved in exocytosis. Proteinases synthesized in the diseased midgut must be rapidly degraded because they do not accumulate in an inactive form.
Identification of candidate genes for fenvalerate resistance in Helicoverpa armigera using cDNA‐AFLP
Authors: Wee C. W. , Lee S. F. , Robin C. , Heckel D. G.
Published: July 2008

A cDNA‐amplified fragment length polymorphisms approach was undertaken to screen for candidate genes associated with fenvalerate resistance in the AN02 strain of Helicoverpa armigera. Larvae and adults of this strain manifest ~50‐fold resistance, which is suppressible by piperonyl butoxide and controlled by the semidominant gene RFen1 previously mapped to AFLP Linkage Group 13. Two cytochrome P450s (CYP337B1 and CYP4S1), one carboxylesterase‐like protein and one glutathione transferase were found to be constitutively upregulated in resistant insects. Mapping of these potential detoxification genes showed that one of them, the novel P450 CYP337B1, was tightly linked to the resistance locus. This suggests that the RFen1R allele has a cis‐acting effect on CYP337B1 expression, and possible trans‐acting effects on expression of other genes.
Differential potency of drosomycin to Neurospora crassa and its mutant: implications for evolutionary relationship between defensins from insects and plants
Authors: Gao B. , Zhu S.‐Y.
Published: July 2008

Drosomycin, the first inducible antifungal peptide isolated from Drosophila, belongs to the superfamily of CSαβ‐type defensins. In the present study we report a modified approach for high‐level expression of drosomycin, which allows us to evaluate its differential potency on the filamentous fungus Neurospora crassa WT (wild type) and N. crassa MUT16, a specific resistance mutant strain to plant defensins, by using different approaches. The results presented here show for the first time that N. crassa MUT16 is resistant to our recombinant drosomycin. Differential survival rates of Drosophila larvae infected by N. crassa WT and MUT16 further confirm the key antifungal role of drosomycin in vivo. The absence of activity against MUT16 suggests a mechanical commonality between drosomycin and plant defensins, which provides additional evidence in favor of their homologous relationship. Furthermore, the existence of drosomycin‐like molecules in fungi suggests that all these peptides could originate from a common ancestry rather than horizontal gene transfer between plants and insects, which is further strengthened by the monophyletic origin of these peptides from plants, fungi and insects.
Identification and expression of theachaete‐scutecomplex in the silkworm,Bombyx mori
Authors: Tong X.‐L. , Dai F.‐Y. , Su M.‐K. , Ma Y. , Tan D. , Zhang Z. , He N.‐J. , Xia Q.‐Y. , Lu C. , Xiang Z.‐H.
Published: July 2008

Recently, the study ofachaete‐scute(AS‐C) homologues has contributed enormously to understanding of gene duplication and function evolution, particularly in Diptera. We identified fourAS‐Chomologue genes in the silkworm,Bombyx mori, referred to asBmASH,BmASH2,BmASH3, andBmase. The complex displayed tandem array structure in the genome. Analysis of spatial expression profiles showed that they all were expressed in obviously higher levels in wing disc than in other tissues, suggesting that they might play important roles in the development of the wing. Furthermore, we found that their expression profiles in the wing discs were mostly correlated with the development of the scales, especially theBmASHgene. RNA interference results further indicated thatBmASHwas necessary for scale formation in silkworm wing.
Cloning and characterisation of a prenyltransferase from the aphid Myzus persicae with potential involvement in alarm pheromone biosynthesis
Authors: Lewis M. J. , Prosser I. M. , Mohib A. , Field L. M.
Published: July 2008

The majority of aphid species release an alarm pheromone with the most common component being the sesquiterpene (E)‐β‐farnesene, sometimes accompanied by other sesquiterpenes or monoterpenes. The genes/enzymes involved in the production of these compounds have not been identified in aphids although some components of isoprenoid biosynthesis have been identified in other insect species. Here we report the cloning, expression and characterisation of a prenyltransferase from the aphid Myzus persicae which can act as a farnesyl pyrophosphate synthase or a geranyl pyrophosphate synthase to produce both sesquiterpenes and monoterpenes and hence could be responsible for the biosynthesis of the observed components of the alarm pheromones. In addition, the enzyme can utilise geranyl pyrophosphate to produce farnesyl pyrophosphate showing that the synthesis of the latter involves the sequential condensation of isoprenyl pyrophosphate units.
In silico prediction and characterization of microRNAs from red flour beetle (Tribolium castaneum)
Authors: Singh J. , Nagaraju J.
Published: July 2008

MicroRNAs (miRNAs), are endogenous, ~22‐nucleotide‐long RNA molecules. They bind to the complementary sites on target mRNAs and regulate protein production of the target transcript by unknown mechanisms. Since the discovery of first miRNA in Caenorhabditis elegans, different approaches have been pursued for the prediction of miRNAs and their target(s). Because of many difficulties and limitations involved in the experimental identification of spatially and temporally expressed miRNAs, many computational approaches have been successfully employed for prediction of miRNAs and their target(s). In the present study, we demonstrate a genome‐wide computational approach to predict miRNAs and their target(s) in the red flour beetle, Tribolium castaneum. We have predicted and characterized 45 miRNAs by genome‐wide homology search against all the reported miRNAs. These miRNAs were further validated by statistical and phylogenetic analyses. In addition, we have also attempted to predict the putative targets of these miRNAs, by making use of 3′ untranslated regions of mRNAs from T. castaneum. These miRNAs and their targets in T. castaneum will serve as useful resources for initiating studies on their experimental validation and functional analyses of miRNA‐regulated phenotypes in T. castaneum through gene knockdown and transgenesis.
Dispersal limitation and geographical distributions of mammal species
Authors: Munguía Mariana , Townsend Peterson Andrew , Sánchez‐Cordero Víctor
Published: July 2008

Aim  To relate the dispersal limitation of endemic terrestrial mammals in Mexico to species life‐history traits and latitude.

Location  Mexico.

Methods  We modelled species ecological niches projected as potential distributions (P) using point occurrence data and 19 environmental variables for 89 endemic mammal species, and compared the areas covered by these ecological niche models with maps of species actual distributions (R) based on minimum convex polygons connecting marginal records based on museum specimens. We correlated body mass, food habits (herbivore, omnivore, insectivore, frugivore/granivore), volant and non‐volant (fossorial, arboreal, terrestrial) habits and mean latitude to the proportion of occupancy of species potential distributional areas (R/P).

Results  R and P were significantly positively correlated, with an overall average R/P ratio of 0.49. Less than half of the endemics (41 species) had a high occupancy (R/P values ranging from 0.50 to 0.90); a few (four species) showed full occupancy (> 0.90). Body mass and food habits were not correlated with R/P, but latitude showed significant correlations with R/P; volant mammals tended to show higher R/P values than non‐volant mammals.

Main conclusions  Few species filled most of the spatial extent of their ecological niches. Life‐history traits were generally poor predictors of proportional occupancy of species potential distributions. Endemics occurring at higher latitudes showed higher occupancy, suggesting that abiotic factors are likely to limit their distributions. Conversely, species at lower latitudes showed lower occupancy, suggesting that their distributions are limited by biotic factors and/or by geographical or historical barriers that prevent dispersal. The dispersal abilities of volant compared with non‐volant endemics can explain the higher occupancy in species potential distributions in the former group. These trends provide a baseline for exploring the importance of life‐history traits and abiotic versus biotic factors in limiting species distributions.
Do feral buffalo (Bubalus bubalis) explain the increase of woody cover in savannas of Kakadu National Park, Australia?
Authors: Bowman D. M. J. S. , Riley J. E. , Boggs G. S. , Lehmann C. E. R. , Prior L. D.
Published: July 2008

Aim  To study changes in woody vegetation in both floodplains and eucalypt savanna over a 40‐year period using multi‐temporal spatial analysis of variation in density of a large introduced herbivore, the Asian water buffalo (Bubalus bubalis). Feral buffalo built up to high densities in the study area until c. 1985, after which a control programme almost eliminated the animals. From 1990, low densities of managed buffalo were maintained inside an enclosure. We compared trends in woody vegetation when buffalo were high‐density feral, low‐density managed or absent.

Location  The study area was located in and around a 116‐km2 buffalo enclosure inside Kakadu National Park, in monsoonal northern Australia.

Methods  We analysed sequences of digitized and geo‐rectified aerial photographs, acquired in 1964, 1975, 1984, 1991 and 2004, to chart changes in woody cover on the floodplain and in the savanna. On the floodplain we assessed whether trees were present at these times at 14,568 points, and buffalo density was estimated from the density of animal tracks. In the savanna we estimated woody cover at pre‐selected sites. Generalized linear modelling was used to analyse changes in woody vegetation, using elevation and presence of woody vegetation in neighbouring points on the floodplain, and buffalo regime and initial woody cover in the savanna.

Results  Changes in animal track density reflected park‐wide historical estimates of buffalo numbers. Tree cover increased in both floodplain and savanna, but this was only weakly related to buffalo density. The best predictor of whether a floodplain cell converted from treeless to woody, or the converse, was the woodiness of neighbouring vegetation. There was slightly less thickening with high buffalo densities. In savanna, low densities of managed buffalo were weakly associated with increases in tree cover relative to either high densities of feral buffalo or no buffalo.

Main conclusions  Our study indicates that buffalo are not a major driver of floodplain and eucalypt savanna dynamics. Rather, the observed increase in woody cover in both savanna and flood plains concords with regional trends and may be related to increased atmospheric CO2, increasing rainfall and changing fire regimes during the study period.
Phylogeography of the pool frog Rana (Pelophylax) lessonae in the Italian peninsula and Sicily: multiple refugia, glacial expansions and nuclear–mitochondrial discordance
Authors: Canestrelli Daniele , Nascetti Giuseppe
Published: July 2008

Aim  To infer the evolutionary history of Rana (Pelophylax) lessonae Camerano within its inferred Quaternary refugial range, and to shed light on the processes that have contributed to shaping the patterns of diversity within the southern European peninsulas.

Location  The Italian peninsula south of the Alps and Sicily.

Methods  Sequence analysis of a mitochondrial cytochrome b gene fragment in 149 individuals sampled from 25 localities.

Results  Three mitochondrial DNA (mtDNA) phylogroups were identified, distributed in northern Italy, the whole Italian peninsula south of the northern Apennines, and Sicily. Syntopy between the northern and peninsular lineages was observed close to the northern Apennines. The northern lineage was the most differentiated, showing a net sequence divergence of 4.8 ± 0.8% with respect to the two others, whereas the net divergence between peninsular and Sicilian lineages was 2.6 ± 0.6%. Analysis of molecular variance (amova) revealed that 93% of the overall variation occurred between these three groups. Historical demographic statistics support a recent expansion for both the northern and peninsular groups, but not for the Sicilian group. In both northern and peninsular Italy, such an expansion was likely to have occurred during the last glaciation.

Main conclusions  Our results suggest that a number of microevolutionary processes were involved in shaping the present genetic structure of R. lessonae in Italy. These encompass allopatric differentiations in three distinct Pleistocene refugia, recent population expansions and secondary contacts. Our results, together with some previous work, support (1) the existence of a suture zone in the northern Apennines, and (2) the possibility of population expansions during the last glacial phase, when a vast widening of the lowland floodplain habitats followed sea‐level fall, particularly in northern Italy. When compared with previous analyses of allozyme data, it appears that the peninsular mtDNA lineage has recently replaced the Sicilian one in southern Calabria, and we suggest that this event occurred due to selective introgression. The implications of such an occurrence for the study of factors underlying the patterns of diversity within this southern European biodiversity hotspot are discussed. Taxonomic implications of the results are also evaluated.
Can spatial variation in epiphyte diversity and community structure be predicted from sampling vascular epiphytes alone?
Authors: Affeld K. , Sullivan J. , Worner S. P. , Didham R. K.
Published: July 2008

Aim  Non‐vascular epiphytes have been largely ignored in studies examining the biotic and abiotic determinants of spatial variation in epiphyte diversity. Our aim was to test whether the spatial patterning of species richness, biomass and community composition across geographic regions, among trees within regions, and among branches within trees is consistent between the vascular and non‐vascular components of the temperate rain forest flora.

Location  Coastal lowland podocarp‐broadleaved forests on the west coast of the South Island of New Zealand.

Methods  We collected single samples (30 × 25 cm) from 96 epiphyte assemblages located on the inner branches of 40 northern rata (Metrosideros robusta) trees. For each sample, branch characteristics such as branch height, branch diameter, branch angle, branch aspect, and minimum and maximum epiphyte mat depth were recorded. The biomass for each individual epiphyte species was determined.

Results  Northern rata was host to a total of 157 species, comprising 32 vascular and 125 non‐vascular species, with liverworts representing 41% of all species. Within epiphyte mats, the average total organic biomass of 3.5 kg m−2 of branch surface area consisted largely of non‐living biomass and roots. Vascular and non‐vascular epiphytes showed strikingly different spatial patterns in species richness, biomass and composition between sites, among trees within sites, and among branches within trees, which could not be explained by the branch structural characteristics we measured. The two plant groups had no significant association in community composition (r = 0.04, P = 0.08). However, the species richness of vascular plant seedlings was strongly linked to the presence/absence of lichens.

Main conclusions  Non‐vascular plants contributed substantially to the high species richness and biomass recorded in this study, which was comparable to that of some tropical rain forests. High variability in community composition among epiphyte mats, and very low correlation with any of the environmental factors measured possibly indicate high levels of stochasticity in seed or spore colonization, establishment success or community assembly among branches in these canopy communities. Although we found some evidence that vascular plant seedling establishment was linked to the presence of lichens and the biomass of non‐living components in the epiphyte mats, there was no correlation in the spatial patterning or determinants of species richness between non‐vascular and vascular plants. Consequently, variation in total epiphyte biodiversity could not be predicted from the measurement of vascular plant diversity alone, which highlights the crucial importance of sampling non‐vascular plants when undertaking epiphyte community studies.
The mid‐domain effect matters: simulation analyses of range‐size distribution data from Mount Kinabalu, Borneo
Authors: Grytnes John‐Arvid , Beaman John H. , Romdal Tom S. , Rahbek Carsten
Published: July 2008

Aim In simulation exercises, mid‐domain peaks in species richness arise as a result of the random placement of modelled species ranges within simulated geometric constraints. This has been called the mid‐domain effect (MDE). Where close correspondence is found between such simulations and empirical data, it is not possible to reject the hypothesis that empirical species richness patterns result from the MDE rather than being the outcome (wholly or largely) of other factors. To separate the influence of the MDE from other factors we therefore need to evaluate variables other than species richness. The distribution of range sizes gives different predictions between models including the MDE or not. Here, we produce predictions for species richness and distribution of range sizes from one model without the MDE and from two MDE models: a classical MDE model encompassing only species with their entire range within the domain (range‐restricted MDE), and a model encompassing all species with the theoretical midpoint within the domain (midpoint‐restricted MDE). These predictions are compared with observations from the elevational pattern of range‐size distributions and species richness of vascular plants.

Location Mount Kinabalu, Borneo.

Methods The data set analysed comprises more than 28,000 plant specimens with information on elevation. Species ranges are simulated with various assumptions for the three models, and the species simulated are subsequently subjected to a sampling that simulates the actual collection of species on Mount Kinabalu. The resulting pattern of species richness and species range‐size distributions are compared with the observed pattern.

Results The comparison of simulated and observed patterns indicates that an underlying monotonically decreasing trend in species richness with elevation is essential to explain fully the observed pattern of richness and range size. When the underlying trend is accounted for, the MDE model that restricts the distributions of theoretical midpoints performs better than both the classical MDE model and the model that does not incorporate geometric constraints.

Main conclusions Of the three models evaluated here, the midpoint‐restricted MDE model is found to be the best for explaining species richness and species range‐size distributions on Mount Kinabalu.
Environmental variation has stronger effects than plant genotype on competition among plant species
Authors: Johnson Marc T. J. , Dinnage Russell , Zhou Alice Y. , Hunter Mark D.
Published: July 2008

Competition is a key factor affecting the performance and co‐existence of species. Most ecological research on competition treats species’ populations as phenotypically homogenous. However, plant populations typically contain genetic variation for multiple traits and have the potential to rapidly adapt to changing environments.

Recent theoretical and empirical research suggests that such variation and evolution may affect the ecological outcome of competitive interactions. We conducted a series of experiments to test the hypothesis whether genetic variation for competitive traits in a native plant (Oenothera biennis) affects the performance and diversity of competing plant species.

In greenhouse and field experiments, the presence ofO. biennisreduced the performance and diversity of neighbouring plant species.

In greenhouse experiments, we detected heritable variation inO. biennisfor above‐ground and below‐ground growth, andO. biennisvaried genetically in response to competition, indicating the potential for adaptive evolution in response to selection by competitors.

Variation amongO. biennisgenotypes also affected the performance of neighbouring plants in the greenhouse, whereby genetic variation inO. biennisshoot : root ratio explained up to 41% of the variation in the performance of an exotic grass (Bromus inermis).

Despite effects ofO. biennisgenotype onB. inermisin the greenhouse, variable soil fertility had a much stronger effect on the grass's performance, and there were no effects ofO. biennisgenotype on neighbouring plants in the field.

Synthesis. Our results show that interspecific competition affected the biomass and diversity of plants, but heritable variation in competitive ability ofO. biennisis not expected to affect short‐term ecological dynamics in this system. Nevertheless,O. biennishas the potential to influence co‐existence over longer timescales by adapting to competitors.
Regulation of Cocaine‐ and Amphetamine‐Regulated Transcript‐Synthesising Neurons of the Hypothalamic Paraventricular Nucleus by Endotoxin; Implications for Lipopolysaccharide‐Induced Regulation of Energy Homeostasis
Authors: Füzesi T. , Sánchez E. , Wittmann G. , Singru P. S. , Fekete C. , Lechan R. M.
Published: July 2008

Infectious diseases and the administration of bacterial lipopolysaccharide (LPS) result in decreased food intake and increased energy expenditure. Because the hypothalamic paraventricular nucleus (PVN) has pivotal roles in the regulation of energy homeostasis and expresses an anorexic peptide, cocaine‐ and amphetamine‐regulated transcript (CART), we hypothesised that increased CART synthesis in this nucleus may contribute to LPS‐induced changes in energy homeostasis. Therefore, we studied the effects of intraperitoneal administration of LPS on CART gene expression in the PVN by semiquantitative in situ hybridisation. LPS caused a rapid increase in CART mRNA levels in the PVN. One hour after treatment, the density of silver grains was increased by three‐fold in the PVN, and remained elevated 3 h after treatment. Because the dorsal vagal complex, an important vegetative centre in the brainstem, is heavily innervated by CART‐containing axons, we determined whether the retrograde tracer, cholera toxin B subunit (CTB), accumulates in CART neurons in the PVN following stereotaxic injection of the tracer into the dorsal vagal complex. One week after injection, CTB accumulated in CART neurons in the ventral, medial, and lateral parvocellular subdivisions of the PVN. In addition, LPS administration induced c‐fos expression in a population of CART neurons in the PVN that project to the dorsal vagal complex. These data indicate that increased CART gene expression in neurons of PVN may contribute to LPS‐induced anorexia, and suggest that this action may be mediated, at least in part, through a PVN‐dorsal vagal complex pathway.
Quantitative analysis of mental health nurse prescribers in Scotland
Authors: SNOWDEN A.
Published: July 2008

The UK parliament approved legislation expanding prescribing rights for all registered nurses in 2006. Mental health nurses do not appear to be embracing prescribing to the same degree as their colleagues. For example, mental health nurses represent 14% of the UK nursing population, but only 3% nurse prescribing population. In order to explore this disparity, the paper discusses quantitative analysis of the following objectives: (1) describe the impact of nurse prescribing on nurse prescribers in NHS Greater Glasgow and Clyde; and (2) identify differences between mental health nurse prescribers and other nurse prescribers in NHS Greater Glasgow and Clyde. Following online pilot study, a 26‐item questionnaire was posted to 668 nurse prescribers in NHS Greater Glasgow and Clyde. A total of 365 questionnaires were returned (55.4%). Significant differences were found between mental health nurse prescribers and others in terms of age, gender, prescribing practice, academic achievement, method of prescribing, workplace, experience and attitude to prescribing. Possible reasons for these differences are suggested and form the basis of further planned research.
Patient aggression in clinical psychiatry: perceptions of mental health nurses
Authors: JONKER E. J. , GOOSSENS P. J. J. , STEENHUIS I. H. M. , OUD N. E.
Published: July 2008

Mental health nurses are faced with an increasing number of aggressive incidents during their daily practice. The coercive intervention of seclusion is often used to manage patient aggression in the Netherlands. However, GGZ Nederland, the Dutch association of service providers for mental health and addition care, has initiated a project to decrease the number of seclusions in clinical psychiatry. A first step in this project is to gain insight into the current situation: the perceived prevalence of patient aggression, the attitudes of mental health nurses towards patient aggression and those socio‐demographic and psychosocial factors that contribute to the use of coercive interventions. A survey was undertaken among 113 nurses from six closed and semi‐closed wards. In this survey, two questionnaires were used: (1) the Attitude Toward Aggression Scale; and (2) the Perceptions of the Prevalence of Aggression Scale. Variables derived from the Theory of Planned Behaviour were also measured. Nurses reported being regularly confronted with aggression in general and mostly with non‐threatening verbal aggression. They perceived patient aggression as being destructive or offensive and not serving a protective or communicative function. The nurses generally perceived themselves as having control over patient behaviour (i.e. considerable self‐efficacy) and reported considerable social support from colleagues. Although the nurses in this study were frequently confronted with aggression, they did not experience the aggression as a major problem.
aglF, aglG and aglI, novel members of a gene island involved in the N‐glycosylation of the Haloferax volcanii S‐layer glycoprotein
Authors: Yurist‐Doutsch Sophie , Abu‐Qarn Mehtap , Battaglia Francesca , Morris Howard R. , Hitchen Paul G. , Dell Anne , Eichler Jerry
Published: July 2008

Proteins in all three domains of life can experience N‐glycosylation. The steps involved in the archaeal version of this post‐translational modification remain largely unknown. Hence, as the next step in ongoing efforts to identify components of the N‐glycosylation pathway of the halophilic archaeon Haloferax volcanii, the involvement of three additional gene products in the biosynthesis of the pentasaccharide decorating the S‐layer glycoprotein was demonstrated. The genes encoding AglF, AglI and AglG are found immediately upstream of the gene encoding the archaeal oligosaccharide transferase, AglB. Evidence showing that AglF and AglI are involved in the addition of the hexuronic acid found at position three of the pentasaccharide is provided, while AglG is shown to contribute to the addition of the hexuronic acid found at position two. Given their proximities in the H. volcanii genome, the transcription profiles of aglF, aglI, aglG and aglB were considered. While only aglF and aglI share a common promoter, transcription of the four genes is co‐ordinated, as revealed by determining transcript levels in H. volcanii cells raised in different growth conditions. Such changes in N‐glycosylation gene transcription levels offer additional support for the adaptive role of this post‐translational modification in H. volcanii.
Expression of reticulon 3 in Alzheimer's disease brain
Authors: Kume H. , Konishi Y. , Murayama K. S. , Kametani F. , Araki W.
Published: July 2008

Aims: Reticulon 3 (RTN3), a member of the reticulon family of proteins, interacts with the β‐secretase, β‐site amyloid precursor protein‐cleaving enzyme 1 (BACE1), and inhibits its activity to produce β‐amyloid protein. The aim of the present study was to clarify the biological role of RTN3 in the brain and its potential involvement in the neuropathology of Alzheimer's disease (AD). Methods: We performed immunohistochemical and biochemical analyses using a specific antibody against RTN3 to investigate the expression and subcellular localization of RTN3 in control and AD brain tissue samples. Results: Western blot analysis revealed no significant differences in the RTN3 levels between control and AD brains. Immunohistochemical staining showed that RTN3 immunoreactivity was predominantly localized in pyramidal neurones of the cerebral cortex. The patterns of RTN3 immunostaining were similar in control and AD cerebral cortices, and senile plaques were generally negative for RTN3. Biochemical subcellular fractionation disclosed that RTN3 colocalized with BACE1 in various fractions, including the endoplasmic reticulum and the Golgi apparatus. Double‐immunofluorescence staining additionally indicated that RTN3 was localized in both endoplasmic reticulum and Golgi compartments in neurones. Conclusions: These results show that RTN3 is primarily expressed in pyramidal neurones of the human cerebral cortex and that no clear difference of RTN3 immunoreactivity is observable between control and AD brains. Our data also suggest that there is considerable colocalization of RTN3 with BACE1 at a subcellular level.
Carbonates within a Pleistocene glaciomarine succession, Yakataga Formation, Middleton Island, Alaska
Authors: JAMES NOEL P. , EYLES CAROLYN H. , EYLES NICHOLAS , HIATT ERIC E. , KURTIS KYSER T.
Published: July 2008

Uplifted during the 1964 Alaskan earthquake, extensive intertidal flats around Middleton Island expose 1300 m of late Cenozoic (Early Pleistocene) Yakataga Formation glaciomarine sediments. These outcrops provide a unique window into outer shelf and upper slope strata that are otherwise buried within the south‐east Alaska continental shelf prism. The rocks consist of five principal facies in descending order of thickness: (i) extensive pebbly mudstone diamictite containing sparse marine fossils; (ii) proglacial submarine channel conglomerates; (iii) burrowed mudstones with discrete dropstone layers; (iv) boulder pavements whose upper surfaces are truncated, faceted and striated by ice; and (v) carbonates rich in molluscs, bryozoans and brachiopods. The carbonates are decimetre scale in thickness, typically channellized conglomeratic event beds interpreted as resedimented deposits on the palaeoshelf edge and upper slope. Biogenic components originated in a moderately shallow (ca80 m), relatively sediment‐free, mesotrophic, sub‐photic setting. These components are a mixture of parautochthonous large pectenids or smaller brachiopods with locally important serpulid worm tubes and robust gastropods augmented by sand‐size bryozoan and echinoderm fragments. Ice‐rafted debris is present throughout these cold‐water carbonates that are thought to have formed during glacial periods of lowered sea‐level that allowed coastal ice margins to advance near to the shelf edge. Such carbonates were then stranded during subsequent sea‐level rise. Productivity was enabled by attenuation of terrigenous mud deposition during these cold periods via reduced sedimentation together with active wave and tidal‐current winnowing near the ice front. Redeposition was the result of intense storms and possibly tsunamis. These sub‐arctic mixed siliciclastic‐carbonate sediments are an end‐member of the Phanerozoic global carbonate depositional realm whose skeletal attributes first appeared during late Palaeozoic southern hemisphere deglaciation.