bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wnt‐signaling and planar cell polarity genes regulate axon guidance along the anteroposterior axis in C. elegans
Authors: Ackley Brian D. 
Published: November 2013

ABSTRACTDuring the development of the nervous system, neurons encounter signals that inform their outgrowth and polarization. Understanding how these signals combinatorially function to pattern the nervous system is of considerable interest to developmental neurobiologists. The Wnt ligands and their receptors have been well characterized in polarizing cells during asymmetric cell division. The planar cell polarity (PCP) pathway is also critical for cell polarization in the plane of an epithelium. The core set of PCP genes include members of the conserved Wnt‐signaling pathway, such as Frizzled and Disheveled, but also the cadherin‐domain protein Flamingo. In Drosophila, the Fat and Dachsous cadherins also function in PCP, but in parallel to the core PCP components. C. elegans also have two Fat‐like and one Dachsous‐like cadherins, at least one of which, cdh‐4, contributes to neural development. In C. elegans Wnt ligands and the conserved PCP genes have been shown to regulate a number of different events, including embryonic cell polarity, vulval morphogenesis, and cell migration. As is also observed in vertebrates, the Wnt and PCP genes appear to function to primarily provide information about the anterior to posterior axis of development. Here, we review the recent work describing how mutations in the Wnt and core PCP genes affect axon guidance and synaptogenesis in C. elegans. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 74: 781–796, 2014
Postnatal development of auditory central evoked responses and thalamic cellular properties
Authors: Venkataraman Yamini , Bartlett Edward L. 
Published: November 2013

ABSTRACTDuring development, the sense of hearing changes rapidly with age, especially around hearing onset. During this period, auditory structures are highly sensitive to alterations of the acoustic environment, such as hearing loss or background noise. This sensitivity includes auditory temporal processing, which is important for processing complex sounds, and for acquiring reading and language skills. Developmental changes can be observed at multiple levels of brain organization—from behavioral responses to cellular responses, and at every auditory nucleus. Neuronal properties and sound processing change dramatically in auditory cortex neurons after hearing onset. However, development of its primary source, the auditory thalamus, or medial geniculate body (MGB), has not been well studied over this critical time window. Furthermore, to understand how temporal processing develops, it is important to determine the relative maturation of temporal processing not only in the MGB, but also in its inputs. Cellular properties of rat MGB neurons were studied using in vitro whole‐cell patch‐clamp recordings, at ages postnatal day (P) 7–9; P15–17, and P22–32. Auditory evoked potentials were measured in P14–17 and P22–32 rats. MGB action potentials became about five times faster, and the ability to generate spike trains increased with age, particularly at frequencies of 50 Hz and higher. Evoked potential responses, including auditory brainstem responses (ABR), middle latency responses (MLR), and amplitude modulation following responses, showed increased amplitudes with age, and ABRs and MLRs additionally showed decreased latencies with age. Overall, temporal processing at subthalamic nuclei is concurrently maturing with MGB cellular properties. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 74: 541–555, 2014
Evaluating the carbon balance estimate from an automated ground‐level flux chamber system in artificial grass mesocosms
Authors: Heinemeyer Andreas , Gornall Jemma , Baxter Robert , Huntley Brian , Ineson Phil 
Published: November 2013

AbstractMeasuring and modeling carbon (C) stock changes in terrestrial ecosystems are pivotal in addressing global C‐cycling model uncertainties. Difficulties in detecting small short‐term changes in relatively large C stocks require the development of robust sensitive flux measurement techniques. Net ecosystem exchange (NEE) ground‐level chambers are increasingly used to assess C dynamics in low vegetation ecosystems but, to date, have lacked formal rigorous field validation against measured C stock changes. We developed and deployed an automated and multiplexed C‐flux chamber system in grassland mesocosms in order rigorously to compare ecosystem total C budget obtained using hourly C‐flux measurements versus destructive net C balance. The system combines transparent NEE and opaque respiration chambers enabling partitioning of photosynthetic and respiratory fluxes. The C‐balance comparison showed good agreement between the two methods, but only after NEE fluxes were corrected for light reductions due to chamber presence. The dark chamber fluxes allowed assessing temperature sensitivity of ecosystem respiration (Reco) components (i.e., heterotrophic vs. autotrophic) at different growth stages. We propose that such automated flux chamber systems can provide an accurate C balance, also enabling pivotal partitioning of the different C‐flux components (e.g., photosynthesis and respiration) suitable for model evaluation and developments.
Vertical patterns of soil water acquisition by non‐native rubber trees (Hevea brasiliensis) in Xishuangbanna, southwest China
Authors: Liu Wenjie , Li Jintao , Lu Hongjian , Wang Pingyuan , Luo Qinpu , Liu Wenyao , Li Hongmei 
Published: November 2013

ABSTRACTThe rubber tree (Hevea brasiliensis) has been extensively cultivated in Xishuangbanna, southwest (SW) China. It shows strong synchronicity for flushing and shedding, displaying a very different phenology to the native vegetation. However, little is known about the water‐use patterns of the plant in this area. We assessed seasonal water‐use strategies of rubber trees over the course of a rainy/dry season cycle. Stable isotope compositions of water in xylem, soil, rain and groundwater were sampled on seasonally distinct dates, and soil water content, root distribution and leaf water potential on sunny days were measured in order to determine the proportion of water derived from different soil layers. Midday leaf water potential of rubber trees was relatively stable throughout the year and did not drop significantly during the late dry season, displaying isohydric behaviour. Soil and stem water isotope signatures along with rooting distributional patterns revealed that rubber trees extracted their water mostly from the top 30 cm and less from below 70 cm of the soil profile during the late rainy season when soil water was plentiful. During the late dry season, as the moisture in the middle soil layers (30–70 cm) was gradually depleted, the depth of water uptake shifted to deeper soil levels. Model calculations showed that the proportion of water uptake from the shallow soil layer (<30 cm) increased markedly after the most recent rainfall in the late dry season and the early rainy season (varying between 65% and 71%), indicating significant plasticity in sources of water uptake in this dimorphic‐rooted species. This ability to take up a large proportion of shallow soil water after rainfall is likely the key feature enabling rubber trees to thrive through the period of greatest water demand. Our results suggest that rubber trees are able to adjust the allocation of resources and thus acclimate to the spatiotemporal changes to water conditions in the soil profile. Copyright © 2013 John Wiley & Sons, Ltd.
Augmenting aquatic species sensitivity distributions with interspecies toxicity estimation models
Authors: Awkerman Jill A. , Raimondo Sandy , Jackson Crystal R. , Barron Mace G. 
Published: November 2013

Abstract

Species sensitivity distributions (SSDs) are cumulative distribution functions of species toxicity values. The SSD approach is being used increasingly in ecological risk assessment but is often limited by available toxicity data needed for diverse species representation. In the present study, the authors evaluate augmenting aquatic species databases limited to standard test species using toxicity values extrapolated from interspecies correlation estimation (ICE) models for SSD development. The authors compared hazard concentrations at the 5th centile (HC5) of SSDs developed using limited measured data augmented with ICE toxicity values (augmented SSDs) with those estimated using larger measured toxicity datasets of diverse species (reference SSDs). When SSDs had similar species composition to the reference SSDs, 0.76 of the HC5 estimates were closer to the reference HC5; however, the proportion of augmented HC5s that were within 5-fold of the reference HC5s was 0.94, compared with 0.96 when predicted SSDs had random species assemblages. The range of toxicity values among represented species in all SSDs also depended on a chemical's mode of action. Predicted HC5 estimations for acetylcholinesterase inhibitors showed the greatest discrepancies from the reference HC5 when SSDs were limited to commonly tested species. The results of the present study indicate that ICE models used to augment datasets for SSDs do not greatly affect HC5 uncertainty. Uncertainty analysis of risk assessments using SSD hazard concentrations should address species composition, especially for chemicals with known taxa-specific differences in toxicological effects. Environ Toxicol Chem 2014;33:688–695. © 2013 SETAC. This article is a US Government work and is in the public domain in the USA.
Effects of bacteriophage on the quality and shelf life of Paralichthys olivaceus during chilled storage
Authors: Li Meng , Lin Hong , Khan Muhammad Naseem , Wang Jingxue , Kong Linghong 
Published: November 2013

AbstractBACKGROUNDThe microbiological spoilage of fishery foods is mainly due to specific spoilage organisms (SSOs), with Shewanella putrefaciens being the SSO of most chilled marine fish. Bacteriophages have shown excellent capability to control micro‐organisms. The aim of this study was to determine a specific bacteriophage to prevent spoilage by reducing SSO (S. putrefaciens) levels in the marine fish Paralichthys olivaceus (olive flounder) under chilled storage.RESULTSChilled flounder fillets were inoculated with S. putrefaciens and treated with different concentrations of bacteriophage Spp001 ranging from 104 to 108 plaque‐forming units (pfu) mL−1. Bacterial growth (including total viable count and SSO) of the bacteriophage‐treated groups was significantly inhibited compared with that of the negative control group (P < 0.05). Sensory evaluation and biochemical parameters revealed that the bacteriophage could extend the shelf life of chilled flounder fillets (from <4 to 14 days) with good esthetic quality, even at low temperature (4 °C). Furthermore, bacteriophage concentrations of 106 and 108 pfu mL−1 were more effective than the chemical preservative potassium sorbate (5 g L−1).CONCLUSIONThe bacteriophage Spp001 offered effective biocontrol of S. putrefaciens under chilled conditions, retaining the quality characteristics of spiked fish fillets, and thus could be a potential candidate for use in chilled fish fillet biopreservation. © 2013 Society of Chemical Industry
Structure elucidation of ACE‐inhibitory and antithrombotic peptides isolated from mackerel skin gelatine hydrolysates
Authors: Khiari Zied , Rico Daniel , Martin‐Diana Ana Belen , Barry‐Ryan Catherine 
Published: November 2013

AbstractBACKGROUNDThe fish‐processing industry generates significant amounts of waste and by‐products that are usually discarded. This study investigated the preparation of bioactive gelatine peptides from fish skin. Gelatine was extracted from mackerel (Scomber scombrus) skin and hydrolysed by pepsin for 1, 2, 6 and 24 h. All hydrolysates were screened for antioxidant, ACE‐inhibitory and antithrombotic activities.RESULTSGelatine peptides obtained after 24 h of hydrolysis exhibited the highest antioxidant activity (DPPH reduction ∼80%, FRAP ∼130 µmol Trolox equivalent L−1). These hydrolysates had high ACE‐inhibitory activity (>70%) and were able to significantly (P < 0.05) inhibit platelet aggregation by about 30%, corresponding to moderate antithrombotic activity.CONCLUSIONThe bioactive properties were mainly due to the presence of low‐molecular‐weight peptides of 337 and 423 Da. © 2013 Society of Chemical Industry
DNA methylation and demethylation: A pathway to gametogenesis and development
Authors: Dean Wendy 
Published: November 2013

SUMMARYThe generation of gametes falls between two reprogramming phases. These phases are characterised by profound periods of transcriptional activity, which define and reinforce lineage decisions. The control of these transcriptional programs and the interpretation of the underlying genetic instruction is the task of the epigenome. As such, dynamic processes during reprogramming are critical for the development of the germ line and its resetting, which propels that developmental process forward and provides the transfer of genetic and epigenetic information between generations. Central in this reprogramming is the addition and subtraction of DNA methylation and its oxidative products, coupled to the mechanisms at play to achieve this goal. The activities competent to add DNA methylation, and identification of those enzymes able to modify it, have heralded a new chapter in our understanding of the complexities that dictate and direct cellular fates. How the early embryos makes use of these marks and how they are modulated will give us insight into cellular differentiation and reprogramming critical for health and into the process of aging. This review details some of these processes and the activities essential to achieve the immortality of the mammalian germ line. Mol. Reprod. Dev. 81: 113–125, 2014. © 2013 Wiley Periodicals, Inc.
Palmitoyl‐protein thioesterase 1 (PPT1): An obesity‐induced rat testicular marker of reduced fertility
Authors: Liu Yue , Zhao Wenzhen , Gu Guobao , Lu Liming , Feng Jingsheng , Guo Qiangsu , Ding Zhide 
Published: November 2013

SUMMARYMale obesity may lead to declines in testosterone levels, reproductive hormonal profile, and semen quantity. To assess the effects of obesity on spermatogenesis, Sprague–Dawley rats fed a high‐fat diet served as a model of induced obesity. The litter sizes for females mated to obese males were significantly lower as compared to females mated with normal‐diet‐fed controls. Their serum high‐density lipoprotein, low‐density lipoprotein, cholesterol, and estradiol levels increased in obese males, but testosterone and follicle‐stimulating hormone levels decreased. Testicular morphology disruptions included Sertoli‐cell atrophy, disrupted tight junctions, and mitochondrial degeneration in spermatogenic cells. To further investigate the molecular mechanisms leading to high‐fat‐diet‐induced changes, we employed testicular proteomic analysis on rats fed both types of diet. Three spots were up‐regulated in rats fed a high‐fat diet whereas two others were downregulated. One of the upregulated spots was palmitoyl‐protein thioesterase 1 (PPT1), a lipoprotein metabolizing related enzyme localized to Sertoli cells. In a Sertoli‐cell line cultured in a high‐fat supplemented medium, PPT1 abundance was accompanied by increases in the endocytic vesicle‐associated protein, clathrin, and decreases in the tight junctional proteins, ZO‐1 and occludin. In conclusion, declines in rat male fertility induced by a high‐fat diet are associated with an altered testicular protein expression pattern as well as disruption of testicular Sertoli‐cell and spermatogenic‐cell morphology. PPT1 expression may provide a testicular marker of reduced fertility in obese males, as increases in its expression may be detrimental to Sertoli‐cell function during spermatogenesis. Mol. Reprod. Dev. 81: 55–65, 2014. © 2013 Wiley Periodicals, Inc.
Eight‐year weight losses with an intensive lifestyle intervention: The look AHEAD study
Authors:   The Look AHEAD Research Group
Published: November 2013

ObjectiveTo evaluate 8‐year weight losses achieved with intensive lifestyle intervention (ILI) in the Look AHEAD (Action for Health in Diabetes) study.Design and MethodsLook AHEAD assessed the effects of intentional weight loss on cardiovascular morbidity and mortality in 5,145 overweight/obese adults with type 2 diabetes, randomly assigned to ILI or usual care (i.e., diabetes support and education [DSE]). The ILI provided comprehensive behavioral weight loss counseling over 8 years; DSE participants received periodic group education only.ResultsAll participants had the opportunity to complete 8 years of intervention before Look AHEAD was halted in September 2012; ≥88% of both groups completed the 8‐year outcomes assessment. ILI and DSE participants lost (mean ± SE) 4.7% ± 0.2% and 2.1 ± 0.2% of initial weight, respectively (P < 0.001) at year 8; 50.3% and 35.7%, respectively, lost ≥5% (P < 0.001), and 26.9% and 17.2%, respectively, lost ≥10% (P < 0.001). Across the 8 years ILI participants, compared with DSE, reported greater practice of several key weight‐control behaviors. These behaviors also distinguished ILI participants who lost ≥10% and kept it off from those who lost but regained.ConclusionsLook AHEAD's ILI produced clinically meaningful weight loss (≥5%) at year 8 in 50% of patients with type 2 diabetes and can be used to manage other obesity‐related co‐morbid conditions.
Deformation kinetics of pH‐sensitive hydrogels
Authors: Toh William , Ng Teng Yong , Liu Zishun , Hu Jianying 
Published: November 2013

AbstractPolymeric gels can undergo large deformation when subjected to external solutions of varying pH. It is imperative to understand the deformation process of pH‐sensitive hydrogels for the effective application of these attractive materials in the biomedical and microfluidic fields. In the modeling of these multi‐phase materials, finite element (FE) modeling is a useful tool for the development of future applications, and it allows developers to test a wide variety of material responses in a cost‐effective and efficient manner, reducing the need to conduct extensive laboratory experiments. Although a FE user‐defined material model is available for the equilibrium state, the transient response of pH‐sensitive gels has not been effectively modeled. Based on our recent work using the heat transfer analogy to tap into the readily available coupled temperature–displacement elements available in the commercial FE software ABAQUS for simulation of the transient swelling process of neutral hydrogels, the transient swelling process of a pH‐sensitive hydrogel is studied and a FE model is further developed to simulate the transient phenomena. Some benchmark examples are investigated to demonstrate the model's capabilities in the simulation of nonlinear deformation kinetics relevant to several applications of pH‐sensitive hydrogels. © 2013 Society of Chemical Industry
Functional amphiphilic oligo(ethylene oxide) methacrylate‐based block copolymers: synthesis by an activator regenerated by electron transfer process for atom transfer radical polymerization and aqueous micellization
Authors: Chan Nicky , Jung Hyun Wook , Noh Seung Man , Oh Jung Kwon 
Published: November 2013

AbstractWell‐defined amphiphilic block copolymers (ABPs) consisting of poly(oligo(ethylene oxide) monomethyl ether methacrylate) (POEOMA) and poly(tert‐butyl methacrylate) (PtBMA) were successfully synthesized using an activator regenerated by electron transfer (ARGET) process for atom transfer radical polymerization (ATRP). Two synthetic routes starting from the synthesis of either PtBMA or POEOMA macroinitiators followed by chain extension with the alternate monomer were examined. The results from a kinetic investigation suggest that both ARGET ATRP of OEOMA and subsequent chain extension with tBMA proceed in a living manner, yielding functional POEOMA‐block‐PtBMA ABPs in the presence of various functional initiators. As a preliminary evaluation for a polymer‐based drug delivery system, the functional ABPs were examined for aqueous micellization through self‐assembly that allows for the preparation of colloidally stable micellar aggregates with various corona morphologies. For flower‐like micelles bearing disulfide linkages in the center of hydrophilic loops, the reductive cleavage of the disulfide linkages enables a facile conversion to thiol‐decorated micelles without a measurable change in particle size. © 2013 Society of Chemical Industry
Solution properties of γ‐crystallins: Compact structure and low frictional ratio are conserved properties of diverse γ‐crystallins
Authors: Chen Yingwei , Zhao Huaying , Schuck Peter , Wistow Graeme 
Published: November 2013

Abstractγ‐crystallins are highly specialized proteins of the vertebrate eye lens where they survive without turnover under high molecular crowding while maintaining transparency. They share a tightly folded structural template but there are striking differences among species. Their amino acid compositions are unusual. Even in mammals, γ‐crystallins have high contents of sulfur‐containing methionine and cysteine, but this reaches extremes in fish γM‐crystallins with up to 15% Met. In addition, fish γM‐crystallins do not conserve the paired tryptophan residues found in each domain in mammalian γ‐crystallins and in the related β‐crystallins. To gain insight into important, evolutionarily conserved properties and functionality of γ‐crystallins, zebrafish (Danio rerio) γM2b and γM7 were compared with mouse γS and human γD. For all four proteins, far UV CD spectra showed the expected β‐sheet secondary structure. Like the mammalian proteins, γM7 was highly soluble but γM2b was much less so. The heat and denaturant stability of both fish proteins was lower than either mammalian protein. The ability of full‐length and truncated versions of human αB‐crystallin to retard aggregation of the heat denatured proteins also showed differences. However, when solution behavior was investigated by sedimentation velocity experiments, the diverse γ‐crystallins showed remarkably similar hydrodynamic properties with low frictional ratios and partial specific volumes. The solution behavior of γ‐crystallins, with highly compact structures suited for the densely packed environment of the lens, seems to be highly conserved and appears largely independent of amino acid composition.