bluuebunny/crossref_metadata_2025 huggingface dataset:
A Myc-regulated transcriptional network controls B-cell fate in response to BCR triggering
Authors: Murn Jernej , Mlinaric-Rascan Irena , Vaigot Pierre , Alibert Olivier , Frouin Vincent , Gidrol Xavier
Published: July 2009

Background

The B cell antigen receptor (BCR) is a signaling complex that mediates the differentiation of stage-specific cell fate decisions in B lymphocytes. While several studies have shown differences in signal transduction components as being key to contrasting phenotypic outcomes, little is known about the differential BCR-triggered gene transcription downstream of the signaling cascades.

Results

Here we define the transcriptional changes that underlie BCR-induced apoptosis and proliferation of immature and mature B cells, respectively. Comparative genome-wide expression profiling identified 24 genes that discriminated between the early responses of the two cell types to BCR stimulation. Using mice with a conditionalMyc-deletion, we validated the microarray data by demonstrating thatMycis critical to promoting BCR-triggered B-cell proliferation. We further investigated theMyc-dependent molecular mechanisms and found thatMycpromotes a BCR-dependent clonal expansion of mature B cells by inducing proliferation and inhibiting differentiation.

Conclusion

This work provides the first comprehensive analysis of the early transcriptional events that lead to either deletion or clonal expansion of B cells upon antigen recognition, and demonstrates thatMycfunctions as the hub of a transcriptional network that control B-cell fate in the periphery.
Natural variation in gene expression in the early development of dauer larvae of Caenorhabditis elegans
Authors: Harvey Simon C , Barker Gary LA , Shorto Alison , Viney Mark E
Published: July 2009

Background

The free-living nematodeCaenorhabditis elegansmakes a developmental decision based on environmental conditions: larvae either arrest as dauer larva, or continue development into reproductive adults. There is natural variation amongC. eleganslines in the sensitivity of this decision to environmental conditions; that is, there is variation in the phenotypic plasticity of dauer larva development. We hypothesised that these differences may be transcriptionally controlled in early stage larvae. We investigated this by microarray analysis of differentC. eleganslines under different environmental conditions, specifically the presence and absence of dauer larva-inducing pheromone.

Results

There were substantial transcriptional differences between fourC. eleganslines under the same environmental conditions. The expression of approximately 2,000 genes differed between genetically different lines, with each line showing a largely line-specific transcriptional profile. The expression of genes that are markers of larval moulting suggested that the lines may be developing at different rates. The expression of a total of 89 genes was putatively affected by dauer larva or non-dauer larva-inducing conditions. Among the upstream regions of these genes there was an over-representation of DAF-16-binding motifs.

Conclusion

Under the same environmental conditions genetically different lines ofC. eleganshad substantial transcriptional differences. This variation may be due to differences in the developmental rates of the lines. Different environmental conditions had a rather smaller effect on transcription. The preponderance of DAF-16-binding motifs upstream of these genes was consistent with these genes playing a key role in the decision between development into dauer or into non-dauer larvae. There was little overlap between the genes whose expression was affected by environmental conditions and previously identified loci involved in the plasticity of dauer larva development.
Enterococci in river Ganga surface waters: Propensity of species distribution, dissemination of antimicrobial-resistance and virulence-markers among species along landscape
Authors: Lata Pushpa , Ram Siya , Agrawal Madhoolika , Shanker Rishi
Published: July 2009

Background

Surface waters quality has declined in developing countries due to rapid industrialization and population growth. The microbiological quality of river Ganga, a life-sustaining surface water resource for large population of northern India, is adversely affected by several point and non-point sources of pollution. Further, untreated surface waters are consumed for drinking and various household tasks in India making the public vulnerable to water-borne diseases and outbreaks. Enterococci, the 'indicator' of water quality, correlates best with the incidence of gastrointestinal diseases as well as prevalence of other pathogenic microorganisms. Therefore, this study aims to determine the distribution of species diversity, dissemination of antimicrobial-resistance and virulence-markers in enterococci with respect to rural-urban landscape along river Ganga in northern India.

Results

Enterococci density (χ2: 1900,df: 1;p< 0.0001) increased from up-to-down gradient sites in the landscape. Species diversity exhibit significant (χ2: 100.4,df: 20;p< 0.0001) and progressive distribution ofE. faecalis,E. faecium,E. duransandE. hiraedown the gradient. Statistically discernible (p: 0.0156 – < 0.0001) background pool of resistance and virulence was observed among differentEnterococcusspp. recovered from five sites in the up-to-down gradient landscape. A significant correlation was observed in the distribution of multiple-antimicrobial-resistance (viz., erythromycin-rifampicin-gentamicin-methicillin and vancomycin-gentamicin-streptomycin;rs: 0.9747;p: 0.0083) and multiple-virulence-markers (viz.,gelE+esp+;rs: 0.9747;p: 0.0083;gelE+efaA+;rs: 0.8944;p: 0.0417) among differentEnterococcusspp.

Conclusion

Our observations show prevalence of multiple-antimicrobial-resistance as well as multiple-virulence traits among differentEnterococcusspp. The observed high background pool of resistance and virulence in enterococci in river waters of populous countries has the potential to disseminate more alarming antimicrobial-resistant pathogenic bacteria of same or other lineage in the environment. Therefore, the presence of elevated levels of virulent enterococci with emerging vancomycin resistance in surface waters poses serious health risk in developing countries like India.
The role of TNFgenetic variants and the interaction with cigarette smoking for gastric cancer risk: a nested case-control study
Authors: Yang Jae Jeong , Ko Kwang-Pil , Cho Lisa Y , Shin Aesun , Gwack Jin , Chang Soung-Hoon , Shin Hai-Rim , Yoo Keun-Young , Kang Daehee , Park Sue K
Published: July 2009

Background

The aim of this study was to investigate the role ofTNFgenetic variants and the combined effect betweenTNFgene and cigarette smoking in the development of gastric cancer in the Korean population.

Methods

We selected 84 incident gastric cancer cases and 336 matched controls nested within the Korean Multi-Center Cancer Cohort. Six SNPs on theTNFgene,TNF-α-238 G/A, -308 G/A, -857 C/T, -863 C/A, -1031 T/C, andTNF-β 252 A/G were genotyped. The ORs (95% CIs) were calculated using unconditional logistic regression model to detect each SNP and haplotype-pair effects for gastric cancer. The combined effects between theTNFgene and smoking on gastric cancer risk were also evaluated. Multi dimensionality reduction (MDR) analyses were performed to explore the potentialTNFgene-gene interactions.

Results

TNF-α-857 C/T containing the T allele was significantly associated with an increased risk of gastric cancer and a linear trend effect was observed in the additive model (OR = 1.6, 95% CI 1.0–2.5 for CT genotype; OR = 2.6, 95% CI 1.0–6.4 for TT genotype). All haplotype-pairs that contained TCT or CCC ofTNF-α-1031 T/C,TNF-α-863 C/A, andTNF-α-857 C/T were associated with a significantly higher risk for gastric cancer only among smokers. In the MDR analysis, regardless of smoking status,TNF-α-857 C/T was included in the first list of SNPs with a significant main effect.

Conclusion

TNF-α-857 C/T polymorphism may play an independent role in gastric carcinogenesis and the risk for gastric cancer byTNFgenetic effect is pronounced by cigarette smoking.
Twist expression promotes migration and invasion in hepatocellular carcinoma
Authors: Matsuo Noriyuki , Shiraha Hidenori , Fujikawa Tatsuya , Takaoka Nobuyuki , Ueda Naoki , Tanaka Shigetomi , Nishina Shinichi , Nakanishi Yutaka , Uemura Masayuki , Takaki Akinobu , Nakamura Shinichiro , Kobayashi Yoshiyuki , Nouso Kazuhiro , Yagi Takahito , Yamamoto Kazuhide
Published: July 2009

Background

Twist, a transcription factor of the basic helix-loop-helix class, is reported to regulate cancer metastasis. It is known to induce epithelial-mesenchymal transition (EMT). In this study, we evaluated the expression of twist and its effect on cell migration in hepatocellular carcinoma (HCC).

Methods

We examined twist expression using immunohistochemistry in 20 tissue samples of hepatocellular carcinoma, and assessed twist expression in HCC cell lines by RT-PCR and Western blot analysis. Ectopic twist expression was created by introducing a twist construct in the twist-negative HCC cell lines. Endogenous twist expression was blocked by twist siRNA in the twist-positive HCC cell lines. We studied EMT related markers, E-cadherin, Vimentin, and N-cadherin by Western blot analysis. Cell proliferation was measured by MTT assay, and cell migration was measured by in vitro wound healing assay. We used immunofluorescent vinculin staining to visualize focal adhesion.

Results

We detected strong and intermediate twist expression in 7 of 20 tumor samples, and no significant twist expression was found in the tumor-free resection margins. In addition, we detected twist expression in HLE, HLF, and SK-Hep1 cells, but not in PLC/RPF/5, HepG2, and Huh7 cells. Ectopic twist-expressing cells demonstrated enhanced cell motility, but twist expression did not affect cell proliferation. Twist expression induced epithelial-mesenchymal transition together with related morphologic changes. Focal adhesion contact was reduced significantly in ectopic twist-expressing cells. Twist-siRNA-treated HLE, HLF, and SK-Hep1 cells demonstrated a reduction in cell migration by 50, 40 and 18%, respectively.

Conclusion

Twist induces migratory effect on hepatocellular carcinoma by causing epithelial-mesenchymal transition.
Statistically significant association of the single nucleotide polymorphism (SNP) rs13181 (ERCC2) with predisposition to Squamous Cell Carcinomas of the Head and Neck (SCCHN) and Breast cancer in the north Indian population
Authors: Mitra Amit Kumar , Singh Neetu , Garg Vivek Kumar , Chaturvedi Rashmi , Sharma Mandira , Rath Srikanta Kumar
Published: July 2009

Background

Non-synonymous single nucleotide polymorphisms (SNPs) within vital DNA repair genes may cause reduction of activity leaving the genome unrepaired resulting in genomic instability and cancer.

Materials and methods

The present endeavour involved study on the association of the SNP rs13181 (Lys751Gln/A18911C) in the Nucleotide Excision Repair (NER) pathway gene ERCC2 (excision repair cross-complementing rodent repair deficiency, complementation group 2) with the risks of Squamous Cell Carcinomas of the Head and Neck (SCCHN) and Breast cancer using a case-control based association study among 685 (400 controls and 285 SCCHN-affected cases) and 395 (227 normal healthy female controls and 168 breast cancer cases) ethnically-matched samples, respectively from north India using Polymerase Chain Reaction followed by Restriction Fragment Length Polymorphism (PCR-RFLP) analysis.

Results

Results showed significant association of rs13181 homozygous mutant (CC) [Odds Ratio (OR) 4.412, 95% Confidence Interval (CI) 2.413 to 8.068], heterozygous (AC) (OR 2.086, 95% CI 1.246 to 3.492) and combined mutant (AC + CC) (OR 2.672, 95% CI 1.647 to 4.334) genotypes with predisposition to Breast cancer. Statistically significant increase in SCCHN risk was also associated with the mutant genotypes of rs13181 (ERCC2), viz. homozygous mutant (CC) (OR 1.680, 95% CI 1.014 to 2.784), heterozygous (AC) (OR 1.531, 95% CI 1.092 to 2.149) and combined mutant (AC + CC) (OR 1.560, 95% CI 1.128 to 2.158) genotypes.

Conclusion

The results of this case-control study indicate that the polymorphism rs13181 might be a risk factor for predisposition towards SCCHN and breast cancer among north Indian subpopulations.
A new paradigm for ammonia excretion in aquatic animals: role of Rhesus(Rh) glycoproteins
Authors: Wright Patricia A. , Wood Chris M.
Published: July 2009

Ammonia excretion at the gills of fish has been studied for 80 years, but the mechanism(s) involved remain controversial. The relatively recent discovery of the ammonia-transporting function of the Rhesus (Rh) proteins, a family related to the Mep/Amt family of methyl ammonia and ammonia transporters in bacteria, yeast and plants, and the occurrence of these genes and glycosylated proteins in fish gills has opened a new paradigm. We provide background on the evolution and function of the Rh proteins, and review recent studies employing molecular physiology which demonstrate their important contribution to branchial ammonia efflux. Rhag occurs in red blood cells,whereas several isoforms of both Rhbg and Rhcg occur in many tissues. In the branchial epithelium, Rhcg appears to be localized in apical membranes and Rhbg in basolateral membranes. Their gene expression is upregulated during exposure to high environmental ammonia or internal ammonia infusion, and may be sensitive to synergistic stimulation by ammonia and cortisol. Rhcg in particular appears to be coupled to H+ excretion and Na+uptake mechanisms. We propose a new model for ammonia excretion in freshwater fish and its variable linkage to Na+ uptake and acid excretion. In this model, Rhag facilitates NH3 flux out of the erythrocyte, Rhbg moves it across the basolateral membrane of the branchial ionocyte, and an apical “Na+/NH +4 exchange complex” consisting of several membrane transporters (Rhcg, V-type H+-ATPase, Na+/H+ exchanger NHE-2 and/or NHE-3, Na+ channel) working together as a metabolon provides an acid trapping mechanism for apical excretion. Intracellular carbonic anhydrase(CA-2) and basolateral Na+/HCO –3cotransporter (NBC-1) and Na+/K+-ATPase play indirect roles. These mechanisms are normally superimposed on a substantial outward movement of NH3 by simple diffusion, which is probably dependent on acid trapping in boundary layer water by H+ ions created by the catalysed or non-catalysed hydration of expired metabolic CO2. Profitable areas for future investigation of Rh proteins in fish are highlighted: their involvement in the mechanism of ammonia excretion across the gills in seawater fish, their possible importance in ammonia excretion across the skin, their potential dual role as CO2 transporters,their responses to feeding, and their roles in early life stages prior to the full development of gills.
Skeletal muscle substrate utilization is altered by acute and acclimatory temperature in the American bullfrog (Lithobates catesbeiana)
Authors: Petersen A. M. , Gleeson T. T.
Published: July 2009

We investigated the effect of acute and acclimatory temperature on the relative contribution of glucose and lactate to metabolism in resting sartorius muscle of the American bullfrog (Lithobates catesbeiana). We examined the fate of these metabolites in vitro by supplying radiolabeled [14C]glucose, [14C]lactate and[14C]palmitate to isolated muscle bundles from frogs (1) acutely exposed to incubation conditions of 5, 15 or 25°C, (2) acclimated for 2–6 weeks to 5 or 25°C or (3) acclimated for 2–6 weeks to 5 or 25°C and the muscles incubated at 15°C. Under all three temperature conditions tested, net rate of lactate metabolism exceeded that of glucose. Acute exposure to 5°C reduced net rate of glucose metabolism by 15×and net lactate metabolism by 10× as compared with 25°C-exposed tissues. Acclimation to 5°C favored glucose storage as glycogen and increased the proportion of lactate oxidized (versus stored or converted to glucose) when compared with 25°C-acclimated tissues. Net rates of storage of lactate as glycogen (glyconeogenesis) were significantly higher in muscles from 5°C-acclimated frogs during incubation at a common temperature of 15°C. These data suggest that lactate is the predominant fuel for resting skeletal muscle over this temperature range, and particularly so under cold conditions. Ready use of lactate as a substrate, and enhancement of glyconeogenic pathways in response to cold acclimation, could play a role in the tolerance of this species to seasonal temperature changes by promoting sequestration and storage of available substrate under cold conditions.
A dynamic model of the windlass mechanism of the foot: evidence for early stance phase preloading of the plantar aponeurosis
Authors: Caravaggi Paolo , Pataky Todd , Goulermas John Y. , Savage Russel , Crompton Robin
Published: July 2009

In the present study we have estimated the temporal elongation of the plantar aponeurosis (PA) during normal walking using a subject-specific multi-segment rigid-body model of the foot. As previous studies have suggested that muscular forces at the ankle can pre-load the PA prior to heel-strike,the main purpose of the current study was to test, through modelling, whether there is any tension present in the PA during early stance phase. Reflective markers were attached to bony landmarks to track the kinematics of the calcaneus, metatarsus and toes during barefoot walking. Ultrasonography measurements were performed on three subjects to determine both the location of the origin of the PA on the plantar aspect of the calcaneus, and the radii of the metatarsal heads. Starting with the foot in a neutral, unloaded position, inverse kinematics allowed calculation of the tension in the five slips of the PA during the whole duration of the stance phase. The results show that the PA experienced tension significantly above rest during early stance phase in all subjects (P<0.01), thus providing support for the PA-preloading hypothesis. The amount of preloading and the maximum elongation of the slips of the PA decreased from medial to lateral. The mean maximum tension exerted by the PA was 1.5 BW (body weight) over the three subjects.
Spiny lobsters use urine-borne olfactory signaling and physical aggressive behaviors to influence social status of conspecifics
Authors: Shabani Shkelzen , Kamio Michiya , Derby Charles D.
Published: July 2009

Decapod crustaceans, like many other animals, engage in agonistic behaviors that enhance their ability to compete for resources with conspecifics. These agonistic behaviors include the release of chemical signals as well as physical aggressive and submissive behaviors. In this study, we report that Caribbean spiny lobsters, Panulirus argus, use both urine-borne chemical signaling and physical aggressive behaviors during interactions with conspecifics, and that these agonistic behaviors can influence the behavior and eventual social status of the interactants. Spiny lobsters that engaged primarily in physical aggressive behaviors became dominant, whereas spiny lobsters that received these physical aggressive behaviors responded with avoidance behaviors and became subordinates. Dominant animals frequently released urine during social interactions, more than when they were not in contact with subordinates and more than when they were not paired with another animal. Subordinates released urine significantly less often than dominants,and no more than when not paired. Preventing release of urine by catheterizing the animals resulted in an increase in the number and duration of physical interactions, and this increase was primarily driven by dominants initiating interactions through physical aggressive behaviors. Introducing urine from one of the catheterized animals into an aquarium reduced physical aggressive behavior by dominant animals to normal levels. Urine-borne signals alone were capable of inducing avoidance behaviors from solitary spiny lobsters in both laboratory and field conditions. We conclude that urine serves as a chemical signal that communicates social status to the interactants. Ablation experiments showed that that these urine signals are detected primarily by aesthetasc sensilla of the olfactory pathway.
Flow structures and fluid transport for the hydromedusaeSarsia tubulosaandAequorea victoria
Authors: Lipinski Doug , Mohseni Kamran
Published: July 2009

The flow structures produced by the hydromedusae Sarsia tubulosaand Aequorea victoria are examined using direct numerical simulation and Lagrangian coherent structures (LCS). Body motion of each hydromedusa is digitized and input to a CFD program. Sarsia tubulosa uses a jetting type of propulsion, emitting a single, strong, fast-moving vortex ring during each swimming cycle while a secondary vortex of opposite rotation remains trapped within the subumbrellar region. The ejected vortex is highly energetic and moves away from the hydromedusa very rapidly. Conversely, A. victoria, a paddling type hydromedusa, is found to draw fluid from the upper bell surface and eject this fluid in pairs of counter-rotating,slow-moving vortices near the bell margins. Unlike S. tubulosa, both vortices are ejected during the swimming cycle of A. victoria and linger in the tentacle region. In fact, we find that A. victoria and S. tubulosa swim with Strouhal numbers of 1.1 and 0.1, respectively. This means that vortices produced by A. victoria remain in the tentacle region roughly 10 times as long as those produced by S. tubulosa, which presents an excellent feeding opportunity during swimming for A. victoria. Finally, we examine the pressure on the interior bell surface of both hydromedusae and the velocity profile in the wake. We find that S. tubulosa produces very uniform pressure on the interior of the bell as well as a very uniform jet velocity across the velar opening. This type of swimming can be well approximated by a slug model, but A. victoria creates more complicated pressure and velocity profiles. We are also able to estimate the power output of S. tubulosa and find good agreement with other hydromedusan power outputs. All results are based on numerical simulations of the swimming jellyfish.
Song competition changes the brain and behavior of a male songbird
Authors: Sockman Keith W. , Salvante Katrina G. , Racke Danielle M. , Campbell C. Ryan , Whitman Buddy A.
Published: July 2009

Males should adjust their behavior and its neural substrates according to the quality of competition that they assess by eavesdropping on other males'courtship signals. In European starlings (Sturnus vulgaris), females base mate choice, in part, on aspects of male song associated with its length,which positively correlates with the males' reproductive success,immunocompetence, age and ability to repel competing males. To determine how variation in the quality of male courtship song affects the brain and behavior of incidental male receivers, we exposed adult male starlings to either long or short songs periodically over 7 days, followed by 1 day of no song. We found no difference between groups in the length (i.e. quality) of songs that subjects produced during the experiment. However, compared with males exposed to short songs, those exposed to long songs sang more songs, exhibited more non-singing activity and, by the end of the experiment, weighed less and had a 30% larger robust nucleus of the arcopallium (RA), a forebrain nucleus that translates pre-motor signals into the appropriate combination of respiratory and syringeal activity. The change in RA volume was not entirely due to variation in song output, suggesting, for the first time, the possibility of acoustically driven plasticity in this motor nucleus. We hypothesize that such neuroplasticity helps prepare the individual for future song output tailored to the prevailing competitive environment.
The role of multiple pheromones in food recruitment by ants
Authors: Dussutour A. , Nicolis S. C. , Shephard G. , Beekman M. , Sumpter D. J. T.
Published: July 2009

In this paper we investigate the foraging activity of an invasive ant species, the big headed ant Pheidole megacephala. We establish that the ants' behavior is consistent with the use of two different pheromone signals, both of which recruit nestmates. Our experiments suggest that during exploration the ants deposit a long-lasting pheromone that elicits a weak recruitment of nestmates, while when exploiting food the ants deposit a shorter lasting pheromone eliciting a much stronger recruitment. We further investigate experimentally the role of these pheromones under both static and dynamic conditions and develop a mathematical model based on the hypothesis that exploration locally enhances exploitation, while exploitation locally suppresses exploration. The model and the experiments indicate that exploratory pheromone allows the colony to more quickly mobilize foragers when food is discovered. Furthermore, the combination of two pheromones allows colonies to track changing foraging conditions more effectively than would a single pheromone. In addition to the already known causes for the ecological success of invasive ant species, our study suggests that their opportunistic strategy of rapid food discovery and ability to react to changes in the environment may have strongly contributed to their dominance over native species.
CFTR Cl– channel functional regulation by phosphorylation of focal adhesion kinase at tyrosine 407 in osmosensitive ion transporting mitochondria rich cells of euryhaline killifish
Authors: Marshall William S. , Watters Kaitlyn D. , Hovdestad Leah R. , Cozzi Regina R. F. , Katoh Fumi
Published: July 2009

Cystic fibrosis transmembrane conductance regulator (CFTR) anion channels are the regulated exit pathway in Cl– secretion by teleost mitochondria rich salt secreting (MR) cells of the gill and opercular epithelia of euryhaline teleosts. By confocal light immunocytochemistry,immunogold transmission electron microscopy (TEM), and co-immunoprecipitation,using regular and phospho-antibodies directed against conserved sites, we found that killifish CFTR (kfCFTR) and the tyrosine kinase focal adhesion kinase (FAK) phosphorylated at Y407 (FAK pY407) are colocalized in the apical membrane and in subjacent membrane vesicles of MR cells. We showed previously that basolateral FAK pY407, unlike other FAK phosphorylation sites, is osmosensitive and dephosphorylates during hypotonic shock of epithelial cells(Marshall et al., 2008). In the present study, we found that hypotonic shock and theα 2-adrenergic agonist clonidine (neither of which affects cAMP levels) rapidly and reversibly inhibit Cl– secretion by isolated opercular membranes, simultaneous with dephosphorylation of FAK pY407, located in the apical membrane. FAK pY407 is rephosphorylated and Cl– secretion rapidly restored by hypertonic shock as well as by forskolin and isoproterenol, which operate via cAMP and protein kinase A. We conclude that hormone mediated, cAMP dependent and osmotically mediated, cAMP independent pathways converge on a mechanism to activate CFTR and Cl– secretion, possibly through tyrosine phosphorylation of CFTR by FAK.
Behavioural and physiological state dependency of host seeking in the blood-sucking insectRhodnius prolixus
Authors: Bodin Aurélie , Vinauger Clément , Lazzari Claudio R.
Published: July 2009

Vertebrate blood is essential for the growth and the reproduction of haematophagous insects. Provided that hosts play the double role of food sources and predators, feeding on their blood exposes these insects to a high predation risk. Therefore, it is expected that host seeking occurs only when insects need to feed. In the present study, we analyse how the feeding status affects the response to host-associated cues in the blood-sucking insect Rhodnius prolixus. We show that the responsiveness to host-associated cues, such as CO2 and heat, and that the motivation to feed depend on the time elapsed since a blood meal. Depending on the time elapsed after feeding, the same concentration of CO2 may attract or repel the insects. As far as we know, this is the first time that a host signal has been shown to be repellent for a haematophagous insect. The response to heat is also modulated but no repellence was observed. When blood was replaced by saline solution as food, a significant reduction of the response to both signals was evinced but repellence was not observed. The injection of haemolymph from fed insects into starved insects inhibited the response of the receiver insects to both signals but this was not observed after the injection of saline solution or of haemolymph from non-fed insects. This is the first time that the modulation of feeding behaviour by the feeding status has been analysed in a hemimetabolous blood-sucking insect, fully excluding any effect of other processes, such as reproduction.
Ecomorphological analysis of aerial performance in a non-specialized lacertid lizard,Holaspis guentheri
Authors: Vanhooydonck Bieke , Meulepas Greet , Herrel Anthony , Boistel Renaud , Tafforeau Paul , Fernandez Vincent , Aerts Peter
Published: July 2009

Controlled aerial descent has evolved at least 30 times independently in different vertebrate and invertebrate lineages. A whole suite of morphological modifications, such as patagia, lateral skin folds and webbed feet, have been suggested to enhance descending ability. In this study, we compare aerial performance (i.e. vertical and horizontal velocity, horizontal distance covered, duration of descent) and morphology (body mass, body width, inter limb distance, surface area and wing loading) among three species of lizards,representing a range of aerial descenders present within the clade. Our performance measurements show that the lacertid Holaspis guentheriperforms intermediately to the specialized gekkonid Ptychozoon kuhliand the rock-dwelling lizard Podarcis muralis. The small relative body mass of H. guentheri results in a low wing loading similar to that of P. kuhli thus enhancing its aerial performance. Whereas the latter generates great lift forces and is able to cover great horizontal distances, H. guentheri's low wing loading seems to be responsible for a slow descent and low impact forces upon landing. Our results show that very small morphological changes may result in noticeable and ecologically relevant changes in performance.
Thermodynamic modelling predicts energetic bottleneck for seabirds wintering in the northwest Atlantic
Authors: Fort Jérôme , Porter Warren P. , Grémillet David
Published: July 2009

Studying the energetics of marine top predators such as seabirds is essential to understand processes underlying adult winter survival and its impact on population dynamics. Winter survival is believed to be the single most important life-history trait in long-lived species but its determinants are largely unknown. Seabirds are inaccessible during this season, so conventional metabolic studies are extremely challenging and new approaches are needed. This paper describes and uses a state-of-the-art mechanistic model, Niche Mapper™, to predict energy expenditure and food requirements of the two main seabird species wintering in the northwest Atlantic. We found that energy demand increased throughout the winter phase in both species. Across this period, mean estimated daily energy requirements were 1306 kJ day–1 for Brünnich's guillemots (Uria lomvia) and 430 kJ day–1 for little auks (Alle alle) wintering off Greenland and Newfoundland. Mean estimated daily food requirements were 547 g wet food day–1 for Brünnich's guillemots, and 289 g wet food day–1 for little auks. For both species and both wintering sites, our model predicts a sharp increase in energy expenditure between November and December, primarily driven by climatic factors such as air temperature and wind speed. These findings strongly suggest the existence of an energetic bottleneck for North Atlantic seabirds towards the end of the year, a challenging energetic phase which might explain recurrent events of winter mass-mortality, so called `seabird winter wrecks'. Our study therefore emphasizes the relevance of thermodynamics/biophysical modelling for investigating the energy balance of wintering marine top predators and its interplay with survival and population dynamics in the context of global change.
Global analysis of alternative splicing uncovers developmental regulation of nonsense-mediated decay in C. elegans
Authors: Barberan-Soler Sergio , Lambert Nicole J. , Zahler Alan M.
Published: July 2009

Alternative splicing coupled to nonsense-mediated decay (AS-NMD) is a mechanism for post-transcriptional regulation of gene expression. We analyzed the global effects of mutations in seven genes of the C. elegans NMD pathway on AS isoform ratios. We find that mutations in two NMD factors, smg-6 and smg-7, have weaker global effects relative to mutations in other smg genes. We did an in-depth analysis of 12 pre-mRNA splicing factor genes that are subject to AS-NMD. For four of these, changes in the ratio of alternatively spliced isoforms during development are caused by developmentally regulated inhibition of NMD, and not by changes in alternative splicing. Using sucrose gradient analysis of mRNAs undergoing translation, we find several examples of NMD-dependent enrichment of premature termination codon (PTC) isoforms in the monosome fraction. In contrast, we present evidence of two genes for which the PTC-containing isoforms are found in polysomes and have a translational profile similar to non-PTC-containing transcripts from the same gene. We propose that NMD of certain alternatively spliced isoforms is regulated, and that some stabilized NMD targets may be translated.
Assessment of Monoclonal Gammopathies by Nephelometric Measurement of Individual Immunoglobulin κ/λ Ratios
Authors: Bradwell Arthur R , Harding Stephen J , Fourrier Nicolas J , Wallis Gregg L F , Drayson Mark T , Carr-Smith Hugh D , Mead Graham P
Published: July 2009

Background: Currently, monoclonal immunoglobulins are identified and quantified from bands on electrophoretic gels. As an alternative, clonality might be determined by measuring the separate light chain types of each Ig class to allow numerical assessment of Ig′κ/Ig′λ ratios, analogous to free light chain κ/λ ratios.

Methods: Using immunization, tolerization, and adsorption procedures, we prepared sheep antibodies against each of the 6 separate molecules, IgGκ, IgGλ, IgAκ, IgAλ, IgMκ, and IgMλ. Antibody targets comprised the junctional epitopes between the heavy chain and light chain domains. After purification, we assessed the antisera on a Siemens Dade-Behring BN™ II nephelometer for analytical quality and clinical utility.

Results: High-avidity, specific antibodies allowed the production of automated nephelometric immunoassays for each Ig light chain type. Laboratory comparison with serum protein electrophoresis, using dilution experiments, showed lower analytical sensitivity for monoclonal IgG detection but similar or greater sensitivity for IgA and IgM, particularly when the monoclonal bands overlaid transferrin. Results obtained from typing of monoclonal proteins into IgG, A, or M types were comparable with results obtained by immunofixation-electrophoresis methods. Initial clinical studies, in multiple myeloma patients, indicated that Ig′κ/Ig′λ ratios were sometimes more sensitive than immunofixation electrophoresis, provided numerical results, and correlated with changes in disease.

Conclusions: Immunoassays for intact Ig κ/λ pairs are possible and should assist in the management of patients with monoclonal gammopathies.
Monomeric C-Reactive Protein Decreases Acetylated LDL Uptake in Human Endothelial Cells
Authors: Schwedler Susanne B , Hansen-Hagge Thomas , Reichert Matthias , Schmiedeke Daniel , Schneider Reinhard , Galle Jan , Potempa Lawrence A , Wanner Christoph , Filep János G
Published: July 2009

Background: C-reactive protein (CRP) is a risk marker for cardiovascular disease and has been implicated in atherogenesis. In atherosclerotic plaques, it colocalizes with oxidized LDL (oxLDL) and promotes oxLDL uptake by macrophages, suggesting an important cross-talk between CRP and lipid processing. A growing body of evidence indicates the existence of distinct configurations of human CRP, native pentameric (nCRP) and structurally modified monomeric (mCRP), that elicit opposing bioactivities in vitro and in vivo. Here, we tested the impact of mCRP and nCRP on the uptake of acetylated LDL (acLDL), which is internalized by receptors similar to those of oxLDL in human endothelial cells.

Methods: We cultured human umbilical vein endothelial cells (HUVECs) for 8 h with mCRP or nCRP (10–100 mg/L) and measured the uptake of acLDL (10–100 mg/L) over a 20-h period by FACS analysis. To assess the receptors involved, we used function-blocking antibodies against Fc γ receptor CD16 (FcγRIII) and CD32 (FcγRII), and RT-PCR analysis of CD16, CD32, and the receptor for oxidized LDL (LOX-1). Uptake of acLDL and CRP isoforms was visualized by immunofluorescence.

Results: Culture of HUVECs with mCRP, but not nCRP, decreased uptake of acLDL, which was not prevented by anti-CD16 or anti-CD32 antibodies. LOX-1, CD16, and CD32 were undetectable by RT-PCR. Immunofluorescence showed decreased cytoplasmic acLDL staining in human umbilical vein endothelial cells (HUVECs) treated with mCRP, but not with nCRP.

Conclusions: Monomeric CRP, but not nCRP, decreased acLDL uptake in human endothelial cells independent of CD16, CD32, or LOX-1. Our data support a protective role of mCRP in cardiovascular disease.
Proficiency Testing of Hb A1c: A 4-Year Experience in Taiwan and the Asian Pacific Region
Authors: Shiesh Shu-Chu , Wiedmeyer Hsiao-Mei , Kao Jau-Tsuen , Vasikaran Samuel D , Lopez Joseph B ,   the Laboratory Management Committee for the Asian-Pacific Federation of Clinical Biochemistry
Published: July 2009

Background: The correlation between hemoglobin A1c (Hb A1c) and risk for complications in diabetic patients heightens the need to measure Hb A1c with accuracy. We evaluated the current performance for measuring Hb A1c in the Asian and Pacific region by examining data submitted by laboratories participating in the Taiwan proficiency-testing program.

Methods: Five fresh-pooled blood samples were sent to participating laboratories twice each year. The results were evaluated against target values assigned by the National Glycohemoglobin Standardization Program network laboratories; a passing criterion of ±7% of the target value was used. Measurement uncertainty at Hb A1c concentrations of 7.0% and 8.0% were determined.

Results: A total of 276 laboratories from 11 countries took part in the Hb A1c survey. At the Hb A1c concentrations tested method-specific interlaboratory imprecision (CVs) were 1.1%–13.9% in 2005, 1.3%–10.1% in 2006, 1.2%–8.2% in 2007, and 1.1%–6.1% in 2008. Differences between target values and median values from the commonly used methods ranged from −0.24% to 0.22% Hb A1c in 2008. In 2005 83% of laboratories passed the survey, and in 2008 93% passed. At 7.0% Hb A1c, measurement uncertainty was on average 0.49% Hb A1c.

Conclusions: The use of accuracy-based proficiency testing with stringent quality criteria has improved the performance of Hb A1c testing in the Asian and Pacific laboratories during the 4 years of assessment.
Investigation on the Bulk Performance and Microstructure of Emulsion-Based, Cold In-Place Recycling Mixtures
Authors: Yan Jinhai , Ni Fujian , Jia Jonathan , Tao Zhuohui
Published: July 2009

Cold in-place recycling (CIR) using asphalt emulsion is a cost-effective method for the preventive and corrective maintenance of existing pavements. The objectives of this study were to evaluate the recycling mixture’s macroscopic performance and to analyze the microstructure of the mastics using a scanning electron microscope (SEM). The overall performance of the recycling material was evaluated for retained stability, immersed freeze-thaw indirect tension tests, and rut testing. Additionally, the surface micro-profiles of three mastic classes were analyzed using SEM. The results of the bulk property analyses indicated that the addition of cement improved the performance of the recycling mixtures. The SEM analyses showed that cement has an effect similar to fiber-reinforcement in cement-treated asphalt emulsion CIR mixtures. Further, the results indicated that the mechanism of cement action is consistent with the results of the overall mixture performance properties.
Comparison of Performance of Asphalt Mixtures Containing Polymer Modifiers
Authors: Behbahani Hamid , Ziari Hassan , Fazaeli Hassan , Rahmani Jafar
Published: July 2009

The purpose of this study is to evaluate and compare the properties of control and modified asphalt mixtures. Two polymers such as styrene butadiene styrene (SBS) and ethylene vinyl acetate (EVA) were used as modifiers, and mixes with different percentages of polymers were prepared by mixing with 60/70 penetration grade unmodified bitumen. Marshall samples were prepared using the modified and unmodified binders and the effect of SBS and EVA on the mechanical properties of the hot mix asphalt has been determined in terms of stability, flow, indirect tensile strength, and rutting resistance. Test results indicated that the polymer modification improved the conventional properties such as penetration, softening point, and temperature susceptibility. It was also conducted that the stability values related to SBS modified specimens increased with an increase in SBS content compared to the control specimens. While, the stability values for EVA modified specimens are smaller than the stability values of the control specimens. Finally, it was observed that the rutting resistance of the modified mixtures for both of polymer modified binders were higher than the control mixtures
On-Line Oil and Grease Monitoring is Instrumental in Short-Time Recovery of Upset Conditions in Produced Water
Authors: Saujon Ralph L. , Sevin Bob J.
Published: July 2009

On-line oil and grease monitoring affords the producer the ability to evaluate equipment and chemical performance in real time. Old methods of collecting and analyzing discrete samples to determine the effectiveness of equipment and chemical programs in produced water being discharged in the Gulf of Mexico may not be suitable in the future. Water moves so rapidly that in many cases, an upset condition can occur undetected for extended periods even while samples are being run periodically. On-line oil and grease monitoring alone will not prevent upset conditions; however, it will alert the producer and allow a prompt response.

This paper deals with a case history of on-line monitoring for a period of 14 months on a platform in the South Timbalier area of the Gulf of Mexico. Using on-line monitoring and current SCADA systems, trending data representing oil ppm versus time can be displayed. By monitoring and evaluating on-line trending data, the root cause of upset conditions can be determined. Data shows that for each upset condition, an identifiable symptom was apparent; therefore, troubleshooting guidelines could be established for this site.

This case history demonstrates the effectiveness, reliability and accuracy of on-line monitoring in the Gulf of Mexico. On-line monitors aid in evaluating equipment, reducing down time, saving manpower, optimizing chemical programs, and minimizing non-compliance time. The case history shows how a useful correlation between EPA methods of oil and grease measurement and on-line monitoring can be derived.
Development of Pedotransfer Functions for Estimation of Soil Hydraulic Parameters using Support Vector Machines
Authors: Twarakavi Navin K. C. , Šimůnek Jirka , Schaap M. G.
Published: July 2009

Modeling flow in variably saturated porous media requires reliable estimates of the hydraulic parameters describing the soil water retention and hydraulic conductivity. These soil hydraulic properties can be measured using a wide variety of laboratory and field methods. Frequently, this proves to be an arduous task because of the high spatial and temporal variability of soil properties. In the last decade, researchers have shown a keen interest in developing a class of indirect approaches, called pedotransfer functions (PTFs), to overcome this problem. Pedotransfer functions predict soil hydraulic parameters using easily obtainable soil properties such as textural information, bulk density and/or few retention points. In this paper, we use a new methodology called Support Vector Machines (SVMs) to derive a new set of PTFs. Support vector machines represent a pattern recognition approach where the overall prediction error and complexity of the SVM structure are minimized simultaneously. We used the same database that was utilized to develop ROSETTA to generate the SVM‐based PTFs. The performance of the SVM‐based PTFs was analyzed using the coefficient of determination, root mean square error (RMSE) and mean error (ME). All soil hydraulic parameters estimated using the SVM‐based PTFs showed improved confidence in the estimates when compared with the ROSETTA PTF program. Estimates of water contents and saturated hydraulic conductivities using the hydraulic parameters predicted by the SVM‐based PTFs mostly improved compared with those obtained using the artificial neural network (ANN)‐based ROSETTA. The RMSE for water contents decreased from 0.062 to 0.034 as more predictors were used, while the RMSE for the saturated hydraulic conductivity decreased from 0.716 to 0.552 (dimensionless log10 units). Similarly, the bias in the water contents estimated using the SVM‐based PTF was reduced significantly compared with ROSETTA.
Soil Carbon and Nitrogen Accumulation in a Forested Debris Flow Chronosequence, California
Authors: Turk Judith K. , Graham Robert C.
Published: July 2009

The role of forest soils in the biogeochemical cycling of C and N is most dynamic during the early stages of soil development. To define C and N trends that occur with soil development in a mixed coniferous forest, a chronosequence formed by debris flows was studied. The accumulation rates of total organic C (TOC) and total N (TN) were evaluated in soils on 10 debris flow deposits, ranging from <1 to 244 yr old. Analysis of the mineral soils was restricted to the 30‐cm depth, since this was the depth of the shallowest debris flows. Carbon was found to accumulate in the organic horizons at a rate of 26.5 g m−2yr−1throughout the time span of the chronosequence. Total organic C accumulation in the mineral horizons (0–30 cm) occurred from 0 to 82 yr at a rate of 13 g m−2yr−1, and was nearly stable from 82 to 244 yr. Total N accumulated at a rate of 0.57 g m−2yr−1in the organic horizons and a rate of 0.17 g m−2yr−1in the mineral horizons (0–30 cm) throughout the 244 yr chronosequence. This study suggests that C accumulation in the upper mineral horizons of young forest soils occurs for <100 yr, while N accumulation is a slower process that occurs for >250 yr. Carbon and N accumulation in the organic horizons, however, both follow a linear trend over the 244‐yr period. The rates of C accumulation suggest a rapid recovery of the soil organic C pool following disturbance.