bluuebunny/crossref_metadata_2025 huggingface dataset:
Time of sowing and the presence of a cover-crop determine the productivity and persistence of perennial pastures in mixed farming systems
Authors: Li Guangdi D. , Hayes Richard C. , McCormick Jeff I. , Gardner Matthew J. , Sandral Graeme A. , Dear Brian S.
Published: October 2014

Incorporation of perennial pastures into cropping rotations can improve whole-farm productivity, profitability and sustainability of mixed farming systems in southern Australia. However, success in establishing perennial pastures depends on choice of species, time of sowing, method of establishment, seasonal conditions, and whether sowing is under a cover-crop. Field experiments were sown from 2008 to 2010 to determine effects of sowing time and the presence of a cover-crop on the performance of four perennial pasture species, lucerne (Medicago sativa L.), chicory (Cichorium intybus L.), phalaris (Phalaris aquatica L.) and cocksfoot (Dactylis glomerata L.), at Yerong Creek, New South Wales (NSW). Results showed that lucerne was the most productive pasture, followed by chicory and phalaris, with cocksfoot being the poorest performer. Under favourable seasonal conditions, lucerne and chicory pastures produced 29.3 and 25.0 t ha–1 of total dry matter (DM), comprising 71% and 52%, respectively, of sown perennial species in the sward in their second growing season, when sown in autumn. Spring-sown pastures produced 24.6 and 18.3 t ha–1 of total DM in the second season, with 55% and 47% of sown species in the sward being lucerne and chicory, respectively. However, spring-sown pastures contained a very low proportion of subterranean clover (Trifolium subterraneum L.) in the sward in the first 2 years, despite efforts to broadcast seeds at the break of season in the following year. It is recommended that non-legume perennial species, such as chicory and phalaris, be sown in autumn with companion annual legumes until methods are developed and tested to establish annual legumes reliably in spring. However, lucerne can be established in autumn or spring because it can fix its own nitrogen and is not reliant on a companion legume. Cocksfoot cv. Kasbah, in general, appears less suitable than the other perennial species for this medium-rainfall environment in southern NSW. Our study showed that pastures sown without a cover-crop had the most reliable establishment, whereas pastures sown with a cover-crop in a dry year had poor establishment or total failure, as well as a significant reduction of grain yield from the cover-crop. In a wet year, pastures established satisfactorily under a cover-crop; however, growth of the cover-crop still suppressed pasture DM production in subsequent years. Research is under way to model our data to determine the likely financial implications of establishing perennial pastures under cover-crops.
Soil-water dynamics in a pasture-cropping system
Authors: Ward P. R. , Lawes R. A. , Ferris D.
Published: October 2014

Pasture cropping is a farming system in which annual crops are sown into established perennial pastures. It may provide environmental benefits such as increased groundcover and reduced deep drainage, while allowing traditional crop production in the Mediterranean-style climate of south-western Australia. In this research, we investigated deep drainage and the temporal patterns of water use by a subtropical perennial grass, annual crops, and a pasture-cropping system over a 4-year period. Both the pasture and pasture-cropped treatments reduced deep drainage significantly, by ~50 mm compared with the crop treatment. Competition between the pasture and crop components altered patterns of average daily water use, the pasture-cropped treatment having the highest water use for July, August and September. Consequently, water-use efficiency for grain production was lower in the pasture-cropped plots. This was offset by pasture production, so that over a full 12-month period, water-use efficiency for biomass production was generally greater for the pasture-cropped plots than for either the pasture or crop monocultures. Pasture cropping may be a viable way of generating sustainable economic returns from both crop and pasture production on sandy soils of south-western Australia.
Nitrogen cycling in summer active perennial grass systems in South Australia: non-symbiotic nitrogen fixation
Authors: Gupta V. V. S. R. , Kroker S. J. , Hicks M. , Davoren C. W. , Descheemaeker K. , Llewellyn R.
Published: October 2014

Non-symbiotic nitrogen (N2) fixation by diazotrophic bacteria is a potential source for biological N inputs in non-leguminous crops and pastures. Perennial grasses generally add larger quantities of above- and belowground plant residues to soil, and so can support higher levels of soil biological activity than annual crops. In this study, the hypothesis is tested that summer-active perennial grasses can provide suitable microsites with the required carbon supply for N2 fixation by diazotrophs, in particular during summer, through their rhizosphere contribution. In a field experiment on a Calcarosol at Karoonda, South Australia, during summer 2011, we measured populations of N2-fixing bacteria by nifH-PCR quantification and the amount of 15N2 fixed in the rhizosphere and roots of summer-active perennial grasses. Diazotrophic N2 fixation estimates for the grass roots ranged between 0.92 and 2.35 mg 15N kg–1 root day–1. Potential rates of N2 fixation for the rhizosphere soils were 0.84–1.4 mg 15N kg–1 soil day–1 whereas the amount of N2 fixation in the bulk soil was 0.1–0.58 mg 15N kg–1 soil day–1. Populations of diazotrophic bacteria in the grass rhizosphere soils (2.45 × 106 nifH gene copies g–1 soil) were similar to populations in the roots (2.20 × 106 nifH gene copies g–1 roots) but the diversity of diazotrophic bacteria was significantly higher in the rhizosphere than the roots. Different grass species promoted the abundance of specific members of the nifH community, suggesting a plant-based selection from the rhizosphere microbial community. The results show that rhizosphere and root environments of summer-active perennial grasses support significant amounts of non-symbiotic N2 fixation during summer compared with cropping soils, thus contributing to biological N inputs into the soil N cycle. Some pasture species also maintained N2 fixation in October (spring), when the grasses were dormant, similar to that found in soils under a cereal crop. Surface soils in the rainfed cropping regions of southern Australia are generally low in soil organic matter and thus have lower N-supply capacity. The greater volume of rhizosphere soil under perennial grasses and carbon inputs belowground can potentially change the balance between N immobilisation and mineralisation processes in the surface soils in favour of immobilisation, which in turn contributes to reduced N losses from leaching.
Developing the role of perennial forages for crop–livestock farms: a strategic multi-disciplinary approach
Authors: Llewellyn Rick S. , Robertson Michael J. , Hayes Richard C. , Ferris David , Descheemaeker Katrien , Revell Clinton
Published: October 2014

Developing new and improved grazing systems for crop–livestock farms where crop production is the major driver of farm management decisions presents a unique research and development challenge. In southern Australia, a substantial proportion of animal production from grazing comes from regions and farms where cropping is the major enterprise. In this paper, we describe a multi-disciplinary farming-systems research approach (EverCrop) aimed at improving farm profitability, risk management and environmental impacts through the development and integration of new grazing options with an emphasis on perennial species. It has been used to analyse and target new opportunities for farmers to benefit from perennial species across dry Mediterranean-type and temperate regions of southern Australia. It integrates field experimentation, on-farm trialling, farmer participatory research, soil–plant–climate biophysical modelling, whole-farm bioeconomic analysis and evaluations of adoptability. Multi-functional roles for summer-active grasses with winter cropping, integration of forage shrubs and establishment of new mixes of perennial grasses in crop rotations to improve farming system performance are identified, along with an analysis of factors likely to affect rate of uptake by farmers.
Visualization and quantification of nascent RAD51 filament formation at single-monomer resolution
Authors: Candelli Andrea , Holthausen Jan Thomas , Depken Martin , Brouwer Ineke , Franker Mariëlla A. M. , Marchetti Margherita , Heller Iddo , Bernard Stéphanie , Garcin Edwige B. , Modesti Mauro , Wyman Claire , Wuite Gijs J. L. , Peterman Erwin J. G.
Published: October 2014

Significance

The mechanism of RAD51-recombinase filament formation is visualized and quantified with single-molecule resolution using a combination of dual optical tweezers, fluorescence microscopy, and microfluidics. With this method, short-lived transient intermediates formed during nascent RAD51 filament assembly were observed directly. It is observed that RAD51 nuclei consisting of a variable number of monomers bind from solution to DNA, with an interaction time that increases with nucleus size. Nuclei that remain bound to DNA long enough can grow by the incorporation of additional RAD51 monomers, stabilizing the RAD51 filament.
KAISO, a critical regulator of p53-mediated transcription of
CDKN1A
and apoptotic genes
Authors: Koh Dong-In , Han Dohyun , Ryu Hoon , Choi Won-Il , Jeon Bu-Nam , Kim Min-Kyeong , Kim Youngsoo , Kim Jin Young , Parry Lee , Clarke Alan R. , Reynolds Albert B. , Hur Man-Wook
Published: October 2014

Significance

Transcription factor KAISO (POZ/BTB family protein, ZBTB33) expression is induced by genotoxic stress in a tumor suppressor p53-dependent manner. KAISO then interacts with p53 and the acetyltransferase p300 to modulate p300 acetylation of p53 and imposing upon p53 a “code,” i.e., acetylation at K320 and K382, and inhibition of acetylation at K381. This coded p53 shows increased DNA binding to p53 response elements in the promoters of
CDKN1A
(cyclin-dependent kinase inhibitor 1) and apoptosis genes, subsequently inducing cell cycle arrest and potent apoptosis. KAISO is a critical regulator of DNA damage responses in multiple cell types and carries out this function by regulating p53-mediated cell cycle arrest and apoptosis.
A receptor-like protein mediates the response to pectin modification by activating brassinosteroid signaling
Authors: Wolf Sebastian , van der Does Dieuwertje , Ladwig Friederike , Sticht Carsten , Kolbeck Andreas , Schürholz Ann-Kathrin , Augustin Sebastian , Keinath Nana , Rausch Thomas , Greiner Steffen , Schumacher Karin , Harter Klaus , Zipfel Cyril , Höfte Herman
Published: October 2014

Significance

Plant growth and development depend on the biosynthesis and remodeling of the cell wall. To coordinate these two processes, surveillance mechanisms have evolved to monitor the state of the cell wall. The brassinosteroid (BR) hormone signaling pathway plays an essential role in growth control and regulates the expression of a plethora of cell wall-related genes. We have previously shown that feedback signaling from the wall can modulate the outputs of the BR pathway, ensuring cell wall homeostasis and integrity. Here, we identified a receptor-like protein (RLP44), which mediates the activation of BR signaling through direct interaction with the BR coreceptor BAK1. Thus, RLP44 integrates cell wall surveillance with hormone signaling to control cell wall integrity and growth.
JAK2V617F promotes replication fork stalling with disease-restricted impairment of the intra-S checkpoint response
Authors: Chen Edwin , Ahn Jong Sook , Massie Charlie E. , Clynes David , Godfrey Anna L. , Li Juan , Park Hyun Jung , Nangalia Jyoti , Silber Yvonne , Mullally Ann , Gibbons Richard J. , Green Anthony R.
Published: October 2014

Significance

Cancers arise through a succession of enabling genetic lesions, but the consequences of many driver mutations remain unclear, especially in the earliest stages of tumor formation. The myeloproliferative neoplasms (MPNs) encompass a group of chronic hematologic disorders that can collectively provide a window into these early stages of leukemia evolution. This study reveals a role for the JAK2V617F mutation, the most frequent genetic abnormality in MPN patients, in impairing replication fork progression during cell division of MPN patient-derived tumor cells. Moreover, analysis of different MPN disease subtypes reveals unexpected differences in DNA repair activity in response to JAK2V617F-induced perturbations in replication dynamics. These findings have potential implications for tumor clonal evolution and individualized cancer therapy.
Allopolyploidy, diversification, and the Miocene grassland expansion
Authors: Estep Matt C. , McKain Michael R. , Vela Diaz Dilys , Zhong Jinshun , Hodge John G. , Hodkinson Trevor R. , Layton Daniel J. , Malcomber Simon T. , Pasquet Rémy , Kellogg Elizabeth A.
Published: October 2014

Significance

Duplication of genomes following hybridization (allopolyploidy) is common among flowering plants, particularly in the grasses that cover vast areas of the world and provide food and fuel. Here, we find that genome duplication has occurred at a remarkable rate, accounting for at least a third of all speciation events in a group of about 1,200 species. Much of this genome duplication occurred during the expansion of the C4grasslands in the Late Miocene. We find no evidence that allopolyploidy leads directly to a change in the net rate of diversification or correlates with the origin of novel morphological characters. However, as a mode of speciation, the frequency of allopolyploidization is surprisingly high.
Neutral molecular cluster formation of sulfuric acid–dimethylamine observed in real time under atmospheric conditions
Authors: Kürten Andreas , Jokinen Tuija , Simon Mario , Sipilä Mikko , Sarnela Nina , Junninen Heikki , Adamov Alexey , Almeida João , Amorim Antonio , Bianchi Federico , Breitenlechner Martin , Dommen Josef , Donahue Neil M. , Duplissy Jonathan , Ehrhart Sebastian , Flagan Richard C. , Franchin Alessandro , Hakala Jani , Hansel Armin , Heinritzi Martin , Hutterli Manuel , Kangasluoma Juha , Kirkby Jasper , Laaksonen Ari , Lehtipalo Katrianne , Leiminger Markus , Makhmutov Vladimir , Mathot Serge , Onnela Antti , Petäjä Tuukka , Praplan Arnaud P. , Riccobono Francesco , Rissanen Matti P. , Rondo Linda , Schobesberger Siegfried , Seinfeld John H. , Steiner Gerhard , Tomé António , Tröstl Jasmin , Winkler Paul M. , Williamson Christina , Wimmer Daniela , Ye Penglin , Baltensperger Urs , Carslaw Kenneth S. , Kulmala Markku , Worsnop Douglas R. , Curtius Joachim
Published: October 2014

Significance

A significant fraction of atmospheric aerosols is formed from the condensation of low-volatility vapors. These newly formed particles can grow, become seeds for cloud particles, and influence climate. New particle formation in the planetary boundary layer generally proceeds via the neutral channel. However, unambiguous identification of neutral nucleating clusters has so far not been possible under atmospherically relevant conditions. We explored the system of sulfuric acid, water, and dimethylamine in a well-controlled laboratory experiment and measured the time-resolved concentrations of neutral clusters. Clusters containing up to 14 sulfuric acid and 16 dimethylamine molecules were observed. Our results demonstrate that a cluster containing as few as two sulfuric acid and one or two dimethylamine molecules is already stable against evaporation.
Identification and characterization of alphavirus M1 as a selective oncolytic virus targeting ZAP-defective human cancers
Authors: Lin Yuan , Zhang Haipeng , Liang Jiankai , Li Kai , Zhu Wenbo , Fu Liwu , Wang Fang , Zheng Xiaoke , Shi Huijuan , Wu Sihan , Xiao Xiao , Chen Lijun , Tang Lipeng , Yan Min , Yang Xiaoxiao , Tan Yaqian , Qiu Pengxin , Huang Yijun , Yin Wei , Su Xinwen , Hu Haiyan , Hu Jun , Yan Guangmei
Published: October 2014

Significance

Although oncolytic virotherapy is showing great promise in clinical trials, not all patients are benefiting. Identifying predictors of therapeutic effectiveness for each oncolytic virus would provide a good chance to increase response rate. Here, we describe an alphavirus (M1) that possesses selective and potent antitumor activity through intravenous infusion, whereas its replication is controlled by the zinc-finger antiviral protein (ZAP) gene. A survey of cancer tissue banks reveals that ZAP is commonly deficient in human cancers, suggesting extensive application prospects of M1. Our work provides an example of a potentially personalized cancer therapy using a targeted oncolytic virus that can be selectively administered to patients with ZAP-deficient tumors. We predict that such agents will form the armamentarium of cancer therapy in the future.
Autism spectrum disorder severity reflects the average contribution of de novo and familial influences
Authors: Robinson Elise B. , Samocha Kaitlin E. , Kosmicki Jack A. , McGrath Lauren , Neale Benjamin M. , Perlis Roy H. , Daly Mark J.
Published: October 2014

Significance

Autism spectrum disorder (ASD) research is complicated by heterogeneity. There are several types of genetic risk factors for ASDs, and that diversity may be reflected in case presentation. This study presents evidence for systematic variation in the genetic architecture of ASDs in which higher functioning cases, defined through cognitive and behavioral assessments, are more likely to manifest familial influences. This finding suggests that genetic and neurobiological research into ASDs and other neuropsychiatric disorders may be pursued more efficiently through greater phenotypic characterization.
Bloom of resident antibiotic-resistant bacteria in soil following manure fertilization
Authors: Udikovic-Kolic Nikolina , Wichmann Fabienne , Broderick Nichole A. , Handelsman Jo
Published: October 2014

Significance

The increasing prevalence of antibiotic-resistant bacteria is one of the most serious threats to public health in the 21st century. One route by which resistance genes enter the food system is through amendment of soils with manure from antibiotic-treated animals, which are considered a reservoir of such genes. Previous studies have associated application of pig manure with the dispersal of sulfonamide-resistance genes to soil bacteria. In this study, we found that dairy cow manure amendment enhanced the proliferation of resident antibiotic-resistant bacteria and genes encoding β-lactamases in soil even though the cows from which the manure was derived had not been treated with antibiotics. Our findings provide previously unidentified insight into the mechanism by which amendment with manure enriches antibiotic-resistant bacteria in soil.
Feedback regulation via AMPK and HIF-1 mediates ROS-dependent longevity in
Caenorhabditis elegans
Authors: Hwang Ara B. , Ryu Eun-A , Artan Murat , Chang Hsin-Wen , Kabir Mohammad Humayun , Nam Hyun-Jun , Lee Dongyeop , Yang Jae-Seong , Kim Sanguk , Mair William B. , Lee Cheolju , Lee Siu Sylvia , Lee Seung-Jae
Published: October 2014

Significance

Reactive oxygen species (ROS) have long been thought to cause aging and considered to be toxic byproducts generated during mitochondrial respiration. Surprisingly, recent studies show that modestly increased ROS levels lengthen lifespan, at least in the roundworm
Caenorhabditis elegans
. It was unclear how the levels of potentially toxic ROS are regulated and how ROS promote longevity. Here we demonstrate that ROS activate two proteins, AMP-activated kinase (AMPK) and hypoxia-inducible factor 1 (HIF-1), to promote longevity by increasing immunity. Further, we find that internal ROS levels are reduced by AMPK while being amplified by HIF-1 when animals are stimulated to have higher ROS levels. Thus, balancing ROS at optimal levels appears to be crucial for organismal health and longevity.
Nitrate foraging by
Arabidopsis
roots is mediated by the transcription factor TCP20 through the systemic signaling pathway
Authors: Guan Peizhu , Wang Rongchen , Nacry Philippe , Breton Ghislain , Kay Steve A. , Pruneda-Paz Jose L. , Davani Ariea , Crawford Nigel M.
Published: October 2014

Significance

Root foraging is a prominent example of phenotypic plasticity where plants proliferate lateral roots preferentially in nutrient-rich zones to compete for nutrients in diverse soil microenvironments. Nitrate (NO
3
−
) is an important source of nitrogen in soils and also serves as a key signal for root development. Our studies demonstrate that the transcription factor TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR1-20 (TCP20) functions in nitrate foraging as an essential part of the systemic signaling pathway that redirects root growth to nitrate-rich zones. An understanding of these molecular mechanisms will assist in efforts to improve nitrogen use efficiency in agriculture and thereby reduce greenhouse gas emissions and pollution of ecosystems.
Defects in T-tubular electrical activity underlie local alterations of calcium release in heart failure
Authors: Crocini Claudia , Coppini Raffaele , Ferrantini Cecilia , Yan Ping , Loew Leslie M. , Tesi Chiara , Cerbai Elisabetta , Poggesi Corrado , Pavone Francesco S. , Sacconi Leonardo
Published: October 2014

Significance

The plasma membrane of cardiac myocytes contains complex invaginations known as transverse tubules (T-tubules). In heart failure, T-tubule loss is a major contributor to Ca
2+
transient abnormalities, leading to weaker and slower contraction. Current therapeutic strategies are often based on attempts to accelerate Ca
2+
transients. Here, we demonstrate that T-tubular loss represents just one way by which T-tubule dysfunction leads to asynchronous Ca
2+
release across the myocyte. In fact, we report that defects in T-tubular electrical activity may contribute to Ca
2+
-mediated arrhythmogenesis not only by favoring asynchronous Ca
2+
release, but also by generating voltage-associated Ca
2+
sparks. This work provides the first description to our knowledge of these novel proarrhythmogenic events that could help guide future therapeutic strategies.
Conformational coupling between the active site and residues within the K
C
-channel of the
Vibrio cholerae cbb
3
-type (C-family) oxygen reductase
Authors: Ahn Young O. , Mahinthichaichan Paween , Lee Hyun Ju , Ouyang Hanlin , Kaluka Daniel , Yeh Syun-Ru , Arjona Davinia , Rousseau Denis L. , Tajkhorshid Emad , Ädelroth Pia , Gennis Robert B.
Published: October 2014

Significance

Many pathogenic bacteria require an aerobic respiratory chain that functions at very low oxygen concentrations. This is accomplished by using a variant of cytochrome
c
oxidase known as cytochrome
cbb
3
. Although related to the human oxidase,
cbb
3
has distinct differences that provide opportunities for developing selective drugs. We used site-directed mutagenesis guided and complemented by molecular dynamics simulations to characterize the essential proton channel within the
cbb
3
from
Vibrio cholerae
. Several critical residues are identified, and evidence is presented to show that perturbations near the entrance of the proton channel can have dramatic effects at the active site of the enzyme, more than 25 Å away. This is among the features that distinguish the pathogen respiratory enzyme from the human enzyme.
Bioinspired micrograting arrays mimicking the reverse color diffraction elements evolved by the butterfly
Pierella luna
Authors: England Grant , Kolle Mathias , Kim Philseok , Khan Mughees , Muñoz Philip , Mazur Eric , Aizenberg Joanna
Published: October 2014

Significance

In the course of evolution, many organisms have developed unique light manipulation strategies that rely on intriguing combinations of a broad range of optical effects generated by materials with sophisticated multiscale hierarchical structural arrangements. By exploiting the optical principles underlying natural structural color, we can generate new photonic materials. Researchers have only just begun to match nature’s morphological and compositional complexity in man-made materials using nanofabrication. We present a bioinspired photonic material that mimics the reverse color-order diffraction found in the butterfly
Pierella luna
. Exploiting and improving the butterfly’s strategy, we create photonic materials that increase our basic understanding of the optical interplay of hierarchical structures and provide a platform for the development of novel photonic devices.
Genetically enhancing mitochondrial antioxidant activity improves muscle function in aging
Authors: Umanskaya Alisa , Santulli Gaetano , Xie Wenjun , Andersson Daniel C. , Reiken Steven R. , Marks Andrew R.
Published: October 2014

Significance

Age-related muscle weakness has major adverse consequences on quality of life, increasing the risk of falls, fractures, and movement impairments. Albeit an increased oxidative state has been shown to contribute to age-dependent reduction in skeletal muscle function, little is known about the mechanisms connecting oxidation and muscle weakness. We show here that genetically enhancing mitochondrial antioxidant activity causes improved skeletal muscle function and voluntary exercise in aged mice. Our findings have broad implications for both the aging and muscle physiology fields, as we present an important molecular mechanism for muscle weakness in aging and skeletal muscle force regulation.
Intestinal permeability, gut-bacterial dysbiosis, and behavioral markers of alcohol-dependence severity
Authors: Leclercq Sophie , Matamoros Sébastien , Cani Patrice D. , Neyrinck Audrey M. , Jamar François , Stärkel Peter , Windey Karen , Tremaroli Valentina , Bäckhed Fredrik , Verbeke Kristin , de Timary Philippe , Delzenne Nathalie M.
Published: October 2014

Significance

Alcohol-dependent subjects frequently develop emotional symptoms that contribute to the persistence of alcohol drinking. These subjects are also characterized by gastrointestinal disturbances. In this study, we showed that alcohol-dependent subjects with altered intestinal permeability had also altered gut-microbiota composition and activity and remained with high scores of depression, anxiety, and alcohol craving after a short-term detoxification program. These results are consistent with the existence of a gut–brain axis in alcohol dependence, in which the gut microbiota could alter the gut-barrier function and influence behavior in alcohol dependence. Therefore, this study opens a previously unidentified field of research for the treatment and the management of alcohol dependence, targeting the gut microbiota.
Ultraefficient homogeneous catalyst for the CO
2
-to-CO electrochemical conversion
Authors: Costentin Cyrille , Passard Guillaume , Robert Marc , Savéant Jean-Michel
Published: October 2014

Significance

Conversion of CO
2
into liquid fuels is one of the most important contemporary energy and environmental challenges. As a first step in this direction, the electrochemical reduction of CO
2
to CO requires catalysts, usually derived from transition metal complexes. In this paper, a very efficient, electrogenerated iron-porphyrin catalyst was obtained by introducing both pendant acid groups and fluorine substituents in the molecule. The former stabilize the CO
2
-catalyst key intermediate via H bonding and provide a high local proton concentration. The latter help decrease the energy required to drive catalysis. Benchmarking this molecule with other catalysts shows that it is at present the most efficient, to the best of our knowledge, homogeneous molecular catalyst of the CO
2
-to-CO conversion in terms of selectivity, overpotential, and turnover frequency.
Public awareness, concerns, and priorities about anthropogenic impacts on marine environments
Authors: Gelcich Stefan , Buckley Paul , Pinnegar John K. , Chilvers Jason , Lorenzoni Irene , Terry Geraldine , Guerrero Matias , Castilla Juan Carlos , Valdebenito Abel , Duarte Carlos M.
Published: October 2014

Significance

We report the results of a 10,106-person pan-European survey of public awareness, concerns, and priorities about marine anthropogenic impacts as a way to inform both science and policy initiatives in achieving marine sustainability. Results enable scientists and policymakers to understand how the public relates to the marine environment and how they frame impacts and can help make managerial, scientific, and policy priorities more responsive to public values.
Label-free electrochemical detection of human methyltransferase from tumors
Authors: Furst Ariel L. , Muren Natalie B. , Hill Michael G. , Barton Jacqueline K.
Published: October 2014

Significance

Epigenetic modifications, including DNA methylation, govern gene expression. Aberrant methylation by DNA methyltransferases can lead to tumorigenesis, so that efficient detection of methyltransferase activity provides an early cancer diagnostic. Current methods, requiring fluorescence or radioactivity, are cumbersome; electrochemical platforms, in contrast, offer high portability, sensitivity, and ease of use. We have developed a label-free electrochemical platform to detect the activity of the most abundant human methyltransferase, DNA(cytosine-5)-methyltransferase1 (DNMT1), and have applied this method in detecting DNMT1 in crude lysates from both cultured human colorectal cancer cells (HCT116) and colorectal tissue samples.
The Potentiation Effect during Serial Conditioning
Authors: Pearce John M. , Nicholas D. J. , Dickinson Anthony
Published: October 2014

The development of suppression in rats to a target conditioned stimulus (CS) was compared in trace and serial conditioning procedures. The interval between the end of the target CS and the shock unconditioned stimulus (US) was filled by a second CS in the serial, but not the trace, procedure. In five experiments the serial procedure produced superior conditioning. This potentiation effect, however, depended critically upon the level of conditioning to the stimulus interpolated between the target CS and the US. When conditioning to the interpolated CS was either reduced by giving independent nonreinforced trials with this CS alone or enhanced by independent reinforced trials, the potentiation effect was abolished. In addition, the insertion of a trace interval between the target and interpolated CSs reduced the effect. However, the magnitude of conditioning to the target CS was unaffected by post-conditioning changes in the conditioned strength of the interpolated CS. These findings are discussed in terms of the contribution of both the association between the CSs themselves, which is inherent in the serial procedure, and that between the target CS and the US.
Variations in the Sensitivity of Instrumental Responding to Reinforcer Devaluation
Authors: Adams Christopher D.
Published: October 2014

In five experiments hungry rats were trained to make a lever press response for a sucrose reinforcer. That sucrose was subsequently devalued by conditioning a food-aversion to it, and the ability of the rats to integrate knowledge about the instrumental contingency with that gained from aversion training was assessed in an extinction test. Experiment I showed successful integration following limited but not extended instrumental training. Experiment II suggested that the crucial factor was the spacing of training; successful integration was seen after massed but not distributed training. The third experiment implicated distributed experience with the reinforcer, rather than distributed response practice, in failures of integration. Experiment IV showed that if the distribution of food-aversion learning was dissimilar to that of instrumental training then a failure of integration could result; this finding was able to account for the distribution of training effects seen in previous studies, but not the effect of extended training. Experiment V replicated the extended training effect seen in Experiment I, and provided evidence that this may reflect the degree of exposure to the reinforcer rather than the extent of response practice.
Blocking as a Retrieval Failure: Reactivation of Associations to a Blocked Stimulus
Authors: Balaz Mary Ann , Gutsin Philip , Cacheiro Haydee , Miller Ralph R.
Published: October 2014

Conditioned lick suppression in rats was used to examine the effectiveness of three different “reminder” treatments in reactivating associations to a blocked stimulus in a Kamin blocking paradigm. Experiment I indicated that with our parameters prior tone-footshock pairings could block manifestation of a light-footshock association that would otherwise be evident following pairings of a light-tone compound stimulus with footshock. In Experiment II, exposure to either the US, the blocked stimulus (light), or the apparatus cues between the compound conditioning trials and testing decreased blocking. Experiments III(a) and III(b) replicated the unblocking effects seen in Experiment II and included control groups that received the identical training and reminder treatments except for the omission of the light from the compound stimulus. These latter animals failed to display behaviour comparable to the blocked and reminded subjects, thereby establishing the associative basis of suppression to the light in the animals reminded following treatment known to produce blocking. Experiment IV also replicated the results of Experiment II and included control groups that received identical light-tone compound trials and reminder treatments without prior conditioning to the tone alone. In these control groups, reminder treatments tended to disrupt rather than increase evidence of conditioning to the light. The results suggest that associations are formed to the added element of a compound despite prior conditioning to the initial element, and that failure on the test trial to retrieve these associations to the blocked CS, rather than a failure to attend to or learn about the added element, is at least in part responsible the Kamin blocking effect.
Septal Driving of the Hippocampal Theta Rhythm Produces a Long-Term, Proactive and Non-Associative Increase in Resistance to Extinction
Authors: Holt Lee , Gray Jeffrey A.
Published: October 2014

Previous experiments employing electrical or pharmacological induction, or instrumental reinforcement, of hippocampal theta rhythm in rats have reported subsequent performance changes in a number of learning situations. In all these studies theta induction took place either concurrent with or following the behaviour under investigation. In the present two experiments, a treatment phase of electrically-induced hippocampal theta (by septal stimulation at 7·7 Hz) preceded acquisition of a discrete trial, barpress response on a fixed ratio 5 reinforcement schedule. In one of three treatment conditions animals received electrical stimulation (1) on its own, or (2) in a classical conditioning relationship with food delivery as unconditioned stimulus, or (3) temporally uncorrelated with food delivery; controls were implanted with electrodes but not stimulated. After 15 days’ acquisition of barpressing, all animals were extinguished over the subsequent 12 days. Results indicated that theta-driving stimulation, independent of any association with food, resulted in increased resistance to extinction of barpressing. In addition, conditions (1) and (3) enhanced the speed of response during early acquisition. These findings cast doubt on a “memory consolidation” hypothesis of hippocampal theta function and demonstrate a non-associative, long-lasting, proactive effect of theta induction on behaviour.
Intermanual Transfer of Mirror-Image Discrimination by Monkeys
Authors: Brown Josephine V. , Ettlinger G.
Published: October 2014

Mirror image equivalence has been studied in four monkeys during inter-manual transfer of tactile discrimination learning. The tasks were designed to progressively reduce the possibility that discrimination would be based on use of the thumb. On three of the four tasks there were consistently significant mirror reversals. The findings support the supposition that mirror inversion occurs during the formation of memory traces, and specifically when the trace is laid down in a second cerebral hemisphere.
The Effects of Postconditioning Revaluation of CS1 and UCS Following Pavlovian Second-Order Electrodermal Conditioning in Humans
Authors: Davey Graham C. L. , McKenna Imelda
Published: October 2014

An experiment is described which uses various inferential post-conditioning revaluation techniques in order to clarify the associative substructure underlying Pavlovian electrodermal conditioning in human subjects. This study established a second-order skin conductance response (SCR) by pairing a CS1 with an aversive 115 dB tone (UCS), and then pairing a different stimulus (CS2) with CS1. The second-order SCR survived post-conditioning extinction of the response to CS1, but was abolished when (i) a post-conditioning habituation procedure resulted in a favourable revaluation of the tone UCS, or (ii) when subjects were given instructions which informed them that there would be no more UCS presentations. These results suggest that in the second-order electrodermal conditioning paradigm described, CR2 is not mediated by S-R links–-as it appears to be in second-order aversive conditioning in nonhuman animals–-but is affected by manipulations which modify the subject's cognitions concerning the UCS.
Learning of Object-Object Associations by Monkeys
Authors: Gaffan David , Bolton Joyce
Published: October 2014

Monkeys were trained in tasks where stimulus objects were presented in pairs, one object of a pair concealing the other, and the monkeys had to displace the top object followed by the bottom object in order to obtain a food reward. In two experiments it was demonstrated that under these conditions the animals formed object-object associations such that the top object recalled in memory the bottom object that had previously been found underneath it. The monkeys were able to discriminate in recall between bottom objects that were identical in secondary reinforcing value and differed only in colour.
Responses to Mirror Image Stimulation and Assessment of Self-Recognition in Mirror- and Peer-Reared Stumptail Macaques
Authors: Anderson James R.
Published: October 2014

Ten stumptail macaques ( Macaca arctoides), varying in experience of conspecifics and mirrors from no experience to extensive experience throughout infancy, were tested for reactions to mirror image stimulation. Monkeys reared only with mirrors or only with one other monkey were highly responsive to their reflections, exhibiting mostly positive behaviour. Monkeys with experience of both a fully accessible cagemate and mirrors were intermediate in responsiveness, while monkeys reared with mirrors but given experience of a live conspecific behind a transparent partition responded least of all to the mirror. Monkeys reared with no experience of conspecifics at all were the most responsive. Rearing experiences influence reactions to social stimuli such as mirror image stimulation, and considerations of the novelty and complexity of the stimuli are important. Despite the most extensive exposure to mirrors yet reported, none of the monkeys showed any evidence of self-recognition.
Pavlovian Counterconditioning is Unchanged by Chlordiazepoxide or by Septal Lesions
Authors: Mcnaughton N , Gray J. A.
Published: October 2014

Two experiments were performed to test whether the minor tranquillizer chlordiaz-epoxide or septal lesions could interfere with Pavlovian counterconditioning. Rats were first trained to bar-press for food on a random interval schedule on which was superimposed the presentation of a light which predicted delivery of a shock. This training continued until all animals were showing stable suppression of responding to the light. Separate groups were then presented, while the manipulandum was retracted from the box, with either a shock paired with the delivery of food or shock and food delivery in a random relationship with one another. This type of intrusion period alternated with the presentation of the light and shock. Pavlovian counterconditioning developed, as shown by progressively less response suppression in the paired groups compared to the random groups. This Pavlovian counterconditioning was in no way reduced by either chlordiazepoxide (5 mg/kg) or by medial or lateral septal lesions. It is argued that these results rule out Pavlovian counterconditioning as a process which is affected by minor tranquillizers or by septal lesions when they interfere with the behavioural tolerance observed after partial punishment or partial reward schedules.
Irrelevant Incentive Learning during Training on Ratio and Interval Schedules
Authors: Dickinson Anthony , Nicholas D. J.
Published: October 2014

Two experiments investigated the effect of a motivationally-induced change in the value of the training reinforcer on instrumental performance. Initially, thirsty rats were trained to lever press for either a sodium or a potassium solution. Responding in an extinction test was then measured following the induction of sodium appetite. In Experiment I sodium-trained rats responded faster in a test given one day following the end of instrumental training. Furthermore, the relative size of this irrelevant incentive effect did not depend upon whether a ratio or interval schedule was employed during training. Delaying the test for eight days following the end of training abolished the difference between the test performance of sodium- and potassium-trained animals. Experiment II provided a further study of the effect of the training schedule when the introduction of the sodium reinforcer was delayed until responding was well established. Again the relative size of the difference between the performance of sodium- and potassium-trained animals was comparable following training on ratio and interval schedules. The insensitivity of this irrelevant incentive effect to the training contingency is in marked contrast to previous failures to detect an effect of reinforcer revaluation brought about by aversion conditioning following training on an interval schedule (Dickinson, Nicholas and Adams, 1983).
Win-Stay Behaviour in the Rat
Authors: Evenden J. L. , Robbins T. W.
Published: October 2014

The Law of Effect dictates that animals will repeat the just-reinforced response “win-stay”, and yet there have been apparent violations of this by rats running for food in mazes, in the form of “win-shift” behaviour. Four experiments analysed the conditions determining win-stay and win-shift behaviour. All the experiments employed a schedule in which reinforcement was distributed across two choices, and in which the probability of reinforcement for the first response after previous reinforcement was equivalent for the two options. Despite this lack of programmed differential reinforcement, rats showed a significant win-stay tendency in Experiment 1, with no spatial bias. Experiments 2 and 3 used respectively a Y-maze and an operant chamber in which responding required a return to a central choice point. In both situations, significant win-shift behaviour resulted initially, at relatively high frequencies of reinforcement, but this win-shift changed to significant win-stay over many sessions, and with intermittent reinforcement. Experiment 4 introduced explicitly non-reinforced trials and demonstrated a “lose-shift” tendency, parallel to win-stay. Possible artefacts underlying win-stay and win-shift behaviour are rejected, and various mechanisms for these effects, including theories of optimal choice and associative learning, are discussed.
Recall of the Goal Box in Latent Learning and Latent Discrimination
Authors: Gaffan David , Gowling E. A.
Published: October 2014

Two experiments showed that in a runway rats recalled incidental features of the goal box which they had previously found at the end of it. They were shown to modify their running speed according to the current associated reward value of the goal box. Retrieval cues for features of the goal box were intra- and extra-maze cues, not the response of running. Two goal boxes differing only in colour could be discriminatively recalled by virtue of their association with two discriminable runways. These experiments disconfound recall of the goal box from place learning as factors in latent learning.
Paleostriatal Lesions and Instrumental Learning in the Pigeon
Authors: Mitchell Jane A. , Hall Geoffrey
Published: October 2014

In three experiments, pigeons with lesions of the paleostriatum (experimental subjects) and unoperated control birds were trained on tasks designed to assess their instrumental learning abilities. In Experiment 1, using an orthodox Skinner box, training was given on a variable interval (VI) followed by a fixed interval (FI) schedule of reinforcement and only non-significant differences between the groups emerged. Experiment 2 examined the performance of the same subjects on a VI schedule in which a response-contingent signal accompanied reinforcement. For control subjects the presence of the signal resulted in a low rate of response compared with that found in equivalent conditions with the signal omitted. Experimental subjects showed the same response rate when the signal was present as when it was absent. Experiment 3 employed naive subjects, and a Skinner box modified to facilitate key-pecking in total darkness. In this apparatus, experimental subjects showed a lowered response rate on a VI schedule. These tasks were analyzed in terms of the classical (stimulus-reinforcer) and instrumental (response-reinforcer) learning they involve. The results suggest that pigeons with paleostriatal lesions show a deficit in forming response-reinforcer associations, perhaps because the lesions reduce the salience of response-produced cues.
Recognition of Maternal Environment in Piglets: Effects of Age and Some Discrete Complex Stimuli
Authors: Horrell R. I. , Eaton Mim
Published: October 2014

Ethological evidence suggests that 1-week-old piglets can distinguish between their own mother or home environment and alien ones. The bases for this discrimination were investigated in two series of experiments employing a T-maze. In the first series, the apparatus was placed between two pens each housing a sow and its piglets, with each of the two goal-arms having a wire mesh end protruding into one of the pens. When piglets from each of these pens (as well as controls from other litters) were run individually in the apparatus, piglets of all ages from 1 to 14 days showed preferential responses towards their home environment. In the second series of experiments, various discrete but complex natural stimuli were placed at the end of the goal-arms: in each case, the stimuli in the two goal-arms were indentical in nature except in their derivation from the maternal pen or an alien one. One-week-old piglets showed a significant preference for their own mother (vs. another sow visible and audible through wire mesh), for wood shavings mixed with sow faeces from their own pen (on the floor of the goal-arm), and for air blown over maternal faeces and shavings. But they showed no evidence of distinguishing between a littermate and another piglet (penned at the other side of the wire mesh terminating a goal-arm).