bluuebunny/crossref_metadata_2025_split huggingface dataset:
Testing Gassmann fluid substitution: sonic logs versus ultrasonic core measurements
Authors: Grochau Marcos , Gurevich Boris 
Published: July 2008

ABSTRACTAlthough 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

AbstractIn 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

Abstract 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

AbstractManagement 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.
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

Summary 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

SummaryChronic 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

AbstractRapid 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

AbstractA 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

AbstractDrosomycin, 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

AbstractRecently, 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

AbstractThe 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

AbstractMicroRNAs (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

AbstractAim  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

AbstractAim  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.