350 research outputs found

    Association of the SULT1A1 R213H polymorphism with colorectal cancer

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    1. Sulphotransferases are a superfamily of enzymes involved in both detoxification and bioactivation of endogenous and exogenous compounds. The arylsulphotransferase SULT1A1 has been implicated in a decreased activity and thermostability when the wild-type arginine at position 213 of the coding sequence is substituted by a histidine. SULT1A1 is the isoform primarily associated with the conversion of dietary N -OH arylamines to DNA binding adducts and is therefore of interest to determine whether this polymorphism is linked to colorectal cancer. 2. Genotyping, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, was performed using DNA samples of healthy control subjects (n = 402) and patients with histologically proven colorectal cancer (n = 383). Both control and test populations possessed similar frequencies for the mutant allele (32.1 and 31%, respectively; P = 0.935). Results were not altered when age and gender were considered as potential confounders in a logistic regression analysis. 3. Examination of the sulphonating ability of the two allozymes with respect to the substrates p -nitrophenol and paracetamol showed that the affinity and rate of sulphonation was unaffected by substitution of arginine to histidine at position 213 of the amino acid sequence. 4. From this study, we conclude that the SULT1A1 R213H polymorphism is not linked with colorectal cancer in this elderly Australian population

    Designing Origami-Adapted Deployable Modules for Soft Continuum Arms

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    © Springer Nature Switzerland AG 2019. Origami has several attractive attributes including deployability and portability which have been extensively adapted in designs of robotic devices. Drawing inspiration from foldable origami structures, this paper presents an engineering design process for fast making deployable modules of soft continuum arms. The process is illustrated with an example which adapts a modified accordion fold pattern to a lightweight deployable module. Kinematic models of the four-sided Accordion fold pattern is explored in terms of mechanism theory. Taking account of both the kinematic model and the materials selection, a 2D flat sheet model of the four-sided Accordion fold pattern is obtained for 3D printing. Following the design process, the deployable module is then fabricated by laminating 3D printed origami skeleton and flexible thermoplastic polyurethane (TPU) coated fabric. Preliminary tests of the prototype shown that the folding motion are enabled mainly by the flexible fabric between the gaps of thick panels of the origami skeleton and matches the kinematic analysis. The proposed approach has advantages of quick scaling dimensions, cost effective and fast fabricating thus allowing adaptive design according to specific demands of various tasks

    Nutritional correlates of koala persistence in a low-density population

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    It is widely postulated that nutritional factors drive bottom-up, resource-based patterns in herbivore ecology and distribution. There is, however, much controversy over the roles of different plant constituents and how these influence individual herbivores and herbivore populations. The density of koala (Phascolarctos cinereus) populations varies widely and many attribute population trends to variation in the nutritional quality of the eucalypt leaves of their diet, but there is little evidence to support this hypothesis. We used a nested design that involved sampling of trees at two spatial scales to investigate how leaf chemistry influences free-living koalas from a low-density population in south east New South Wales, Australia. Using koala faecal pellets as a proxy for koala visitation to trees, we found an interaction between toxins and nutrients in leaves at a small spatial scale, whereby koalas preferred trees with leaves of higher concentrations of available nitrogen but lower concentrations of sideroxylonals (secondary metabolites found exclusively in eucalypts) compared to neighbouring trees of the same species. We argue that taxonomic and phenotypic diversity is likely to be important when foraging in habitats of low nutritional quality in providing diet choice to tradeoff nutrients and toxins and minimise movement costs. Our findings suggest that immediate nutritional concerns are an important priority of folivores in low-quality habitats and imply that nutritional limitations play an important role in constraining folivore populations. We show that, with a careful experimental design, it is possible to make inferences about populations of herbivores that exist at extremely low densities and thus achieve a better understanding about how plant composition influences herbivore ecology and persistence.IW and WF received a grant from New South Wales (NSW) Department of Environment, Climate Change & Water

    Gene expression of circulating tumour cells in breast cancer patients

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    <p>Abstract</p> <p>Background</p> <p>The diagnostic tools to predict the prognosis in patients suffering from breast cancer (BC) need further improvements. New technological achievements like the gene profiling of circulating tumour cells (CTC) could help identify new prognostic markers in the clinical setting. Furthermore, gene expression patterns of CTC might provide important informations on the mechanisms of tumour cell metastasation.</p> <p>Materials and methods</p> <p>We performed realtime-PCR and multiplex-PCR analyses following immunomagnetic separation of CTC. Peripheral blood (PB) samples of 63 patients with breast cancer of various stages were analyzed and compared to a control group of 14 healthy individuals. After reverse-transcription, we performed multiplex PCR using primers for the genes <it>ga733.3, muc-1 </it>and <it>c-erbB2. Mammaglobin1, spdef </it>and <it>c-erbB2 </it>were analyzed applying realtime-PCR.</p> <p>Results</p> <p><it>ga733.2 </it>overexpression was found in 12.7% of breast cancer cases, <it>muc-1 </it>in 15.9%, <it>mgb1 </it>in 9.1% and <it>spdef </it>in 12.1%. In this study, <it>c-erbB2 </it>did not show any significant correlation to BC, possibly due to a highly ambient expression. Besides single gene analyses, gene profiles were additionally evaluated. Highly significant correlations to BC were found in single gene analyses of <it>ga733.2 </it>and <it>muc-1 </it>and in gene profile analyses of <it>ga733.3</it>*<it>muc-1 </it>and GA7 <it>ga733.3</it>*muc-1*<it>mgb1</it>*<it>spdef</it>.</p> <p>Conclusion</p> <p>Our study reveals that the single genes <it>ga733.3, muc-1 </it>and the gene profiles <it>ga733.3</it>*<it>muc-1 </it>and <it>ga733.3</it>*3<it>muc-1</it>*<it>mgb1</it>*<it>spdef </it>can serve as markers for the detection of CTC in BC. The multigene analyses found highly positive levels in BC patients. Our study indicates that not single gene analyses but subtle patterns of multiple genes lead to rising accuracy and low loss of specificity in detection of breast cancer cases.</p

    Declining Orangutan Encounter Rates from Wallace to the Present Suggest the Species Was Once More Abundant

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    BACKGROUND: Bornean orangutans (Pongo pygmaeus) currently occur at low densities and seeing a wild one is a rare event. Compared to present low encounter rates of orangutans, it is striking how many orangutan each day historic collectors like Alfred Russel Wallace were able to shoot continuously over weeks or even months. Does that indicate that some 150 years ago encounter rates with orangutans, or their densities, were higher than now? METHODOLOGY/PRINCIPAL FINDINGS: We test this hypothesis by quantifying encounter rates obtained from hunting accounts, museum collections, and recent field studies, and analysing whether there is a declining trend over time. Logistic regression analyses of our data support such a decline on Borneo between the mid-19th century and the present. Even when controlled for variation in the size of survey and hunting teams and the durations of expeditions, mean daily encounter rates appear to have declined about 6-fold in areas with little or no forest disturbance. CONCLUSIONS/SIGNIFICANCE: This finding has potential consequences for our understanding of orangutans, because it suggests that Bornean orangutans once occurred at higher densities. We explore potential explanations-habitat loss and degradation, hunting, and disease-and conclude that hunting fits the observed patterns best. This suggests that hunting has been underestimated as a key causal factor of orangutan density and distribution, and that species population declines have been more severe than previously estimated based on habitat loss only. Our findings may require us to rethink the biology of orangutans, with much of our ecological understanding possibly being based on field studies of animals living at lower densities than they did historically. Our approach of quantifying species encounter rates from historic data demonstrates that this method can yield valuable information about the ecology and population density of species in the past, providing new insight into species' conservation needs

    Unexpected Ecological Resilience in Bornean Orangutans and Implications for Pulp and Paper Plantation Management

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    Ecological studies of orangutans have almost exclusively focused on populations living in primary or selectively logged rainforest. The response of orangutans to severe habitat degradation remains therefore poorly understood. Most experts assume that viable populations cannot survive outside undisturbed or slightly disturbed forests. This is a concern because nearly 75% of all orangutans live outside protected areas, where degradation of natural forests is likely to occur, or where these are replaced by planted forests. To improve our understanding of orangutan survival in highly altered forest habitats, we conducted population density surveys in two pulp and paper plantation concessions in East Kalimantan, Indonesia. These plantations consist of areas planted with fast-growing exotics intermixed with stands of highly degraded forests and scrublands. Our rapid surveys indicate unexpectedly high orangutan densities in plantation landscapes dominated by Acacia spp., although it remains unclear whether such landscapes can maintain long-term viable populations. These findings indicate the need to better understand how plantation-dominated landscapes can potentially be incorporated into orangutan conservation planning. Although we emphasize that plantations have less value for overall biodiversity conservation than natural forests, they could potentially boost the chances of orangutan survival. Our findings are based on a relatively short study and various methodological issues need to be addressed, but they suggest that orangutans may be more ecologically flexible than previously thought

    How Plants Sense Wounds: Damaged-Self Recognition Is Based on Plant-Derived Elicitors and Induces Octadecanoid Signaling

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    Background: Animal-derived elicitors can be used by plants to detect herbivory but they function only in specific insect– plant interactions. How can plants generally perceive damage caused by herbivores? Damaged-self recognition occurs when plants perceive molecular signals of damage: degraded plant molecules or molecules localized outside their original compartment. Methodology/Principal Findings: Flame wounding or applying leaf extract or solutions of sucrose or ATP to slightly wounded lima bean (Phaseolus lunatus) leaves induced the secretion of extrafloral nectar, an indirect defense mechanism. Chemically related molecules that would not be released in high concentrations from damaged plant cells (glucose, fructose, salt, and sorbitol) did not elicit a detectable response, excluding osmotic shock as an alternative explanation. Treatments inducing extrafloral nectar secretion also enhanced endogenous concentrations of the defense hormone jasmonic acid (JA). Endogenous JA was also induced by mechanically damaging leaves of lima bean, Arabidopsis, maize, strawberry, sesame and tomato. In lima bean, tomato and sesame, the application of leaf extract further increased endogenous JA content, indicating that damaged-self recognition is taxonomically widely distributed. Transcriptomic patterns obtained with untargeted 454 pyrosequencing of lima bean in response to flame wounding or the application of leaf extract or JA were highly similar to each other, but differed from the response to mere mechanical damage. W

    5, 8, 11, 14-eicosatetraynoic acid suppresses CCL2/MCP-1 expression in IFN-γ-stimulated astrocytes by increasing MAPK phosphatase-1 mRNA stability

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    <p>Abstract</p> <p>Background</p> <p>The peroxisome proliferator-activated receptor (PPAR)-α activator, 5,8,11,14-eicosatetraynoic acid (ETYA), is an arachidonic acid analog. It is reported to inhibit up-regulation of pro-inflammatory genes; however, its underlying mechanism of action is largely unknown. In the present study, we focused on the inhibitory action of ETYA on the expression of the chemokine, CCL2/MCP-1, which plays a key role in the initiation and progression of inflammation.</p> <p>Methods</p> <p>To determine the effect of ETYA, primary cultured rat astrocytes and microglia were stimulated with IFN-γ in the presence of ETYA and then, expression of CCL2/MCP-1 and MAPK phosphatase (MKP-1) were determined using RT-PCR and ELISA. MKP-1 mRNA stability was evaluated by treating actinomycin D. The effect of MKP-1 and human antigen R (HuR) was analyzed by using specific siRNA transfection system. The localization of HuR was analyzed by immunocytochemistry and subcellular fractionation experiment.</p> <p>Results</p> <p>We found that ETYA suppressed CCL2/MCP-1 transcription and secretion of CCL2/MCP-1 protein through up-regulation of MKP-1mRNA levels, resulting in suppression of c-Jun N-terminal kinase (JNK) phosphorylation and activator protein 1 (AP1) activity in IFN-γ-stimulated brain glial cells. Moreover, these effects of ETYA were independent of PPAR-α. Experiments using actinomycin D revealed that the ETYA-induced increase in MKP-1 mRNA levels reflected an increase in transcript stability. Knockdown experiments using small interfering RNA demonstrated that this increase in MKP-1 mRNA stability depended on HuR, an RNA-binding protein known to promote enhanced mRNA stability. Furthermore, ETYA-induced, HuR-mediated mRNA stabilization resulted from HuR-MKP-1 nucleocytoplasmic translocation, which served to protect MKP-1 mRNA from the mRNA degradation machinery.</p> <p>Conclusion</p> <p>ETYA induces MKP-1 through HuR at the post-transcriptional level in a receptor-independent manner. The mechanism revealed here suggests eicosanoids as potential therapeutic modulators of inflammation that act through a novel target.</p
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