bluuebunny/crossref_metadata_2025 huggingface dataset:
Nutritive value of herbage from mountain hay meadow managed under traditional and intensive harvest systems as affected by nitrogen fertilisation and time of cutting
Authors: Bochi-Brum O. , García R. , Bodas R. , Calleja A. , Andrés S. , López S.
Published: May 2011

The aim of this study was to investigate the influence of harvest season and nitrogen (N) fertilisation on chemical composition and digestibility of the herbage harvested from a mountain meadow (of the vegetation type Arrhenatheretalia). Four rates of N fertiliser (0, 60, 120 and 180 kg N/ha per year in a single spring application of calcium ammonium nitrate) were compared in field-replicated plots. The experiment lasted 7 years. During the first 3 years each plot was harvested twice per year (June and September) according to a traditional harvest system, whereas in the last 3 years (after a transitional year) each plot was harvested three times per year (spring, summer and autumn) following a more intensive harvest system. In both harvest systems, herbage collected in the first cut (early or late June) had higher fibre contents and lower digestibility (P < 0.001) than herbage collected in the regrowth. N fertiliser increased significantly (P < 0.001) the annual yield of herbage in the 2-harvest system, but did not affect (P > 0.10) herbage yield in the 3-cuts system. N fertiliser changed the botanical composition of herbage and promoted grass growth, resulting in increased (P < 0.05) fibre content and decreased (P < 0.05) digestibility and rate of degradation of herbage, these effects being variable in the different harvest seasons. Our results suggest that the more intensive management system without N fertilisation could be considered a suitable practice for the management of these botanically complex mountain meadows. These results may contribute to design fertilisation and management practices of mountain hay meadows to optimise their productivity and sustainability.
Effect of ewe body condition and nutrition in late pregnancy on the performance of triplet-bearing ewes and their progeny
Authors: Kenyon P. R. , Morris S. T. , Stafford K. J. , West D. M.
Published: May 2011

The aim of the present study was to determine the production response of triplet-bearing ewes and their lambs to two differing feeding treatments in mid to late pregnancy and to determine the effect of ewe body condition. Ninety-two days after the start of their breeding period (P92) triplet-bearing ewes, were allocated to either a Medium (n = 72) or ad libitum (‘Adlib’, n = 72) feeding treatment until P113, followed by both groups being merged and offered ad libitum feeding conditions until lambing. The Medium feeding treatment was designed to ensure pre- and postgrazing herbage masses were below 1200 and 1000 kg DM/ha, respectively. Each feeding treatment included ewes from the following body condition score groups: 2.0 or less (CS ≤2.0), 2.5 (CS2.5) or 3.0 or greater (CS ≥3.0). At P113, Medium ewes were lighter (P < 0.05) and had lower (P < 0.05) body condition scores than Adlib ewes (72.4 ± 0.80 vs 75.2 ± 0.85 kg and 2.8 ± 0.06 vs 3.3 ± 0.06, respectively). However, at P141 liveweight no longer differed (P > 0.05, 86.2 ± 0.94 vs 86.6 ± 0.99 kg, respectively), although a small difference in condition score remained (P < 0.05, 3.0 ± 0.07 vs 3.3 ± 0.08, respectively). Ewe feeding treatment had no effect (P > 0.05) on lamb liveweight or survival or ewe liveweight and body condition during lactation. Ewe body condition score group had no effect (P > 0.05) on lamb birthweight. Lambs born to CS2.5 group ewes were heavier 70 days after the midpoint of lambing (L70) than those born to CS ≤2.0 group ewes (20.9 ± 0.41 vs 19.6 ± 0.36 kg, respectively), although they displayed lower survival to L70 (56.0 vs 69.5%). Liveweight at L70 and survival of lambs born to CS ≥3.0 group ewes (20.0 ± 0.39 kg and 61.7%) did not differ (P > 0.05) from those born to either CS ≤2.0 or CS2.5 group ewes. In conclusion, these results suggest triplet-bearing ewes can be maintained under restricted feeding conditions until at least Day 113 of pregnancy without negatively affecting ewe or lamb performance when they are subsequently offered unrestricted feeding for the remainder of pregnancy and during lactation. Under these grazing conditions the body condition of triplet-bearing ewes had little to no effect on their subsequent performance or that of their lambs.
Pregnancy rate and prolificacy after artificial insemination in ewes following synchronisation with prostaglandin, sponges, or sponges with bactericide
Authors: Viñoles C. , Paganoni B. , Milton J. T. B. , Driancourt M. A. , Martin G. B.
Published: May 2011

Pregnancy rate and prolificacy were studied in ewes after cycle synchronisation by either progestagen sponges plus equine chorionic gonadotrophin (eCG) or by three injections of prostaglandin (PG). We also tested whether there was any advantage in treating the sponges with antibiotic before insertion. In Experiment 1, 207 Corriedale ewes were treated with intravaginal sponges for 14 days and given 250 IU eCG at sponge withdrawal. For half of the ewes, the sponges had been sprayed with chlortetracycline whereas the other half received untreated sponges. Ewes were ranked within each group based on the amount of mucus and odour of the sponges at the time of withdrawal (score 0 = none, + = mild, ++ = abundant) and the result was compared with pregnancy rate. An average of 155 ± 5.5 million spermatozoa (range 96–248 million) were deposited in the vagina 55 h after sponge withdrawal. The actual dose was measured for each ewe so the dose effect could be studied. Adding antibiotics reduced the amount of mucus (57% of ewes with score 0 in the antibiotic group versus 31% in the Control group; P < 0.01) and odour (98% of ewes with score 0 in the Antibiotic group versus 11% in the Control group; P < 0.001) but had no effect on pregnancy rate (58% for the Antibiotic group versus 48% of controls; P > 0.05) at any sperm dose. In Experiment 2, Merino ewes were treated with intravaginal sponges for 14 days and given 200 IU eCG at sponge removal (n = 100), or were subjected to three PG injections 7 days apart (n = 100). Intrauterine insemination with 200 million sperm was carried out 53 h after the end of synchronisation treatment. Pregnancy rate was higher in the sponge plus eCG group than in the PG group (85 versus 47%; P < 0.001) but prolificacy was similar (1.34 versus 1.38; P > 0.05). We conclude that, under the conditions of these experiments, synchronisation with sponges plus eCG and PG resulted in similar prolificacy, but pregnancy rate was significantly lower with the three PG injections. There seems to be no benefit for pregnancy rate of pretreating sponges with chlortetracycline.
An economic case study of entire male grain-fed beef from a north-western Queensland production system
Authors: Wainewright S. A. , Parker A. J. , Holmes W. E. , Zerby H. , Fitzpatrick L. A.
Published: May 2011

Assessing the differences in gross margins for a north-western Queensland beef-production system was undertaken using herd-budgeting software. The analysis reviewed the viability of producing beef for the domestic market from either a steer or bull production system. A hypothetical herd of 1200 breeders was created for the case study evaluation. An integrated beef production system from breeding to feedlot finishing was found to be less profitable for bull beef production than for steers at the current market prices. Although bull production was more profitable than steer production during the feedlot phase, the production of bulls in this phase failed to compensate for the earlier economic losses in the weaning phase of –AU$24.04 per adult equivalent for bulls. During the feedlot phase, bull production systems had lower break-even sale prices than did steer production systems. In reviewing two pricing scenarios for bulls, it was found that marketing bulls at the same price as steers was the most profitable production system. We conclude that the production of bull beef from a north-western Queensland production system can be profitable only if bulls can be sold without discount relative to steers.
Challenge by a novel object does not impair the capacity of ewes and lambs selected for a nervous temperament to display early preference for each other
Authors: Bickell Samantha , Nowak Raymond , Poindron Pascal , Chadwick Aprille , Ferguson Drewe , Blache Dominique
Published: May 2011

Novelty, a powerful fear-inducing and stressful stimulus, could be detrimental on the capacity of ewes and lambs to recognise each other. The effect of a novel object on the ability of ewes and lambs, selected for their calm or nervous temperament, to show a preference for each other was tested in a two-choice discrimination test. Both calm and nervous temperament mothers showed a preference towards their own offspring rather than the alien lambs. Nervous temperament ewes also looked at their own lamb more than the alien. In contrast, nervous lambs showed a greater preference and took less time to reach their own mother than calm lambs. Nervous temperament does not seem to impair the capacity of ewes and lambs to display an early preference for each other, and might be an advantage in some challenging postnatal situations because of the increased motivation of nervous lambs to reunite with their mother.
Innovation of head-marking in Humburi Senni (Songhay, Mali)
Authors: Heath Jeffrey
Published: May 2011

Humburi Senni (HS), the Songhay language spoken in the town of Hombori in Mali, has innovated not one but two suffixal pronominal-possessor paradigms for nouns (inalienable vs. alienable), a suffixal pronominal-complement paradigm for (original) postpositions, and a suffixal Imperative Singular for verbs. These are absent (with one very limited, but important, exception) in other Songhay languages, including HS’s nearest genetic neighbor. The effect is that HS has veered sharply toward head-marking, which is virtually absent in other Songhay languages. However, its specific typological profile is unusual, with head-marking well-developed for nouns and adpositions but absent from nonimperative verbs/clauses. We can reconstruct the sequence of events (crucially involving the encliticization of opportunistically appended independent pronouns) that result in the attested paradigms. As a result of these innovations, plus another innovation involving the morphology of unpossessed nouns, an original Definite Singular suffix *-òó now has four reflexes — none of which is now definite. Neither language contact nor demographic disruption played a role in the innovations; instead, the initial catalyst for the head-marking was probably the monophthongization of 1sg proclitic *ay to *i, merging segmentally with 3pl proclitic *i.
Modal grammaticalization and the pragmatic field
Authors: Hill Virginia
Published: May 2011

This paper proposes a diachronic syntactic analysis of the Romanian verb putea “can”. It is argued that the grammaticalization of putea consists of several upward reanalyses, and the gradual stripping of semantic features set off its reclassification as control verb > raising verb > auxiliary > pragmatic marker. This analysis accounts for ambiguous epistemic/deontic readings on the modal, which were considered mysterious under lexical/semantic approaches; it also explains why infinitive verbs are so productive as complements to the modal; and it points out that conversational pragmatic features must be factored in as triggers of syntactic reanalysis.
Perfective and imperfective from the same source
Authors: Lin You-Jing
Published: May 2011

Extensive typological research on spatiotemporal development has shown that directionals tend to start as ‘bounders’, and eventually grammaticalize into perfective or simple-past markers. Meanwhile, recent crosslinguistic studies of tense and aspect have demonstrated that the opposition between perfective and imperfective is the most general contrast expressed via verbal morphology. This paper, however, presents a clear counterexample to the above commonly accepted generalizations. Specifically, rGyalrong languages show a perfective-imperfective distinction, but the past imperfective marker and one of the perfectives developed from the same source — the directional ‘down’. This study thus documents a previously undescribed development, through which a single directional has grammaticalized into two opposing aspectual categories. The unexpected spatio-temporal development presents a challenge to the approach of grammaticalization studies that focuses on ‘major’ developmental pathways.
Tying up loose ends
Authors: McWhorter John
Published: May 2011

Since the introduction of the Creole Prototype hypothesis in 1998, much of the controversy it has occasioned has centered on a question as to whether it is scientifically appropriate to reconstruct creoles as born as pidgins, rather than as results of only moderately transformational second-language acquisition or as simply mixtures of ‘features’ from assorted languages coming together. This paper first outlines traits in creoles that reveal their origin in pidgins. Then, the paper refines the characterization of the Creole Prototype’s three features, regarding inflectional morphology, tone, and compositionality of derivation-root combinations. The inflectional component is refined to incorporate Booij’s (1993) distinction between contextual and inherent inflection and Kihm’s (2003) proposal that inflectional morphology can be either bound or free. The tonal stipulation is refined in view of traits of Mon-Khmer phonology that distinguish these languages from creoles despite their analyticity, and the grammatical uses of tone in some creoles such as Papiamentu and Principense. Finally, for the derivational component, an account is proposed for the noncompositionality of reduplicated forms that have been observed in many creoles. The conclusion is that there remains a synchronic characterization possible only in languages recently born from pidgins, and impossible of older (i.e. most) languages.
Heritage and Innovation in the Grammatical Analysis of Latin
Authors: Visser Louise J.
Published: May 2011

TheArs Ambrosianais an early medieval Latin grammatical commentary on Donatus’Ars maior, written in Northern Italy in the 6th or 7th century A.D. In comparison with preceding grammatical commentaries, theArs Ambrosianadisplays a much more profound Christian-exegetical way of thinking. This study opens with an overview of the historicalcultural context of the grammatical commentary and of the general way of thinking of its anonymous author. The remainder of the article consists in an analysis of the, to some extent highly original, framework which the author uses for describing the Latin language, illustrated by a brief study of the termsagnitio(“recognition”) andnuntiatio(“[linguistic] form”), and their combinations with the adjectivesspecialis(“special”) andtota(“entire/ whole”).
John Bulwer and the Quest for a Universal Language, 1641–1644
Authors: Wollock Jeffrey
Published: May 2011

A pioneer of the language sciences, John Bulwer (1606–1656) published on universal language at the beginning of the English ‘scientific revolution’. The Comenians, centered in Bulwer’s own city of London and known for open communication, were interested in this subject area; yet Bulwer’s contact with them, if any, is unclear. This article argues that Bulwer’s Baconian research program on expression and gesture was the response of a non-puritan physician to the convergence of three factors: publication of John Wilkins’sMercury(1641); ongoing discussions about universal language during Comenius’s stay in England (September 1641–June 1642); and the religious-political crisis of the time.
On the Origins of the TermPhoneme
Authors: Mugdan Joachim
Published: May 2011

Hitherto unknown works by Antoni Dufriche-Desgenettes (1804–1878) show that he used the termphonèmeearlier than assumed until now: the word is attested in manuscripts of March 1865 but the publication of the first article in which it occurs was apparently delayed until 1868. Possibly, Dufriche did not “invent” the expression himself but borrowed it, at least indirectly, from the Bulgarian philosopher Petăr Beron (c. 1799–1871), who had used it several years previously for the sound aspect of a word. This usage may also be the reason why some later authors applied the termphonèmeto sound sequences.
Roman Jakobson’s Kindersprache, Aphasie und allgemeine Lautgesetze (1941) and Alf Sommerfelt
Authors: Jahr Ernst Håkon
Published: May 2011

This article suggests a link between Roman Jakobson’s Kindersprache, Aphasie und allgemeine Lautgesetze (1941) and a short book review of C. & W. Stern’s Die Kindersprache (4th ed., 1928) by Alf Sommerfelt in Norsk Tidsskrift for Sprogvidenskap (1929). The fundamental idea of Kindersprache is that children’s phonological systems develop from initial broad contrasts to subsequent finer contrasts, so that unmarked phonological oppositions which are found in most languages develop first, with any language-specific contrasts developing later. In aphasia, according to Jakobson, the opposite development occurs: finer contrasts disappear first, broader contrasts later. It is shown in this article that Jakobson, in working out this theory, was probably inspired by an idea put forward in the 1929 book review by Sommerfelt. This may help to explain why Jakobson, on the first page of Kindersprache, dedicated his book ‘Til min venn Alf ’ (“To my friend Alf ”). Jakobson worked on and completed Kindersprache during his stay in Scandinavia 1939–1941, and details connected with his stay and work in this period are also commented on.
Valerie Weaver: Overcoming cancer's stiff resistance
Authors: Sedwick Caitlin
Published: May 2011

Weaver investigates the mechanical properties of tumors and how changes in the tumor microenvironment influence cancer cell behavior.
Real-time imaging of cotranscriptional splicing reveals a kinetic model that reduces noise: implications for alternative splicing regulation
Authors: Schmidt Ute , Basyuk Eugenia , Robert Marie-Cécile , Yoshida Minoru , Villemin Jean-Philippe , Auboeuf Didier , Aitken Stuart , Bertrand Edouard
Published: May 2011

Splicing is a key process that expands the coding capacity of genomes. Its kinetics remain poorly characterized, and the distribution of splicing time caused by the stochasticity of single splicing events is expected to affect regulation efficiency. We conducted a small-scale survey on 40 introns in human cells and observed that most were spliced cotranscriptionally. Consequently, we constructed a reporter system that splices cotranscriptionally and can be monitored in live cells and in real time through the use of MS2–GFP. All small nuclear ribonucleoproteins (snRNPs) are loaded on nascent pre-mRNAs, and spliceostatin A inhibits splicing but not snRNP recruitment. Intron removal occurs in minutes and is best described by a model where several successive steps are rate limiting. Each pre-mRNA molecule is predicted to require a similar time to splice, reducing kinetic noise and improving the regulation of alternative splicing. This model is relevant to other kinetically controlled processes acting on few molecules.
PKCζ mediates disturbed flow-induced endothelial apoptosis via p53 SUMOylation
Authors: Heo Kyung-Sun , Lee Hakjoo , Nigro Patrizia , Thomas Tamlyn , Le Nhat-Tu , Chang Eugene , McClain Carolyn , Reinhart-King Cynthia A. , King Michael R. , Berk Bradford C. , Fujiwara Keigi , Woo Chang-Hoon , Abe Jun-ichi
Published: May 2011

Atherosclerosis is readily observed in regions of blood vessels where disturbed blood flow (d-flow) is known to occur. A positive correlation between protein kinase C ζ (PKCζ) activation and d-flow has been reported, but the exact role of d-flow–mediated PKCζ activation in atherosclerosis remains unclear. We tested the hypothesis that PKCζ activation by d-flow induces endothelial cell (EC) apoptosis by regulating p53. We found that d-flow–mediated peroxynitrite (ONOO−) increased PKCζ activation, which subsequently induced p53 SUMOylation, p53–Bcl-2 binding, and EC apoptosis. Both d-flow and ONOO− increased the association of PKCζ with protein inhibitor of activated STATy (PIASy) via the Siz/PIAS-RING domain (amino acids 301–410) of PIASy, and overexpression of this domain of PIASy disrupted the PKCζ–PIASy interaction and PKCζ-mediated p53 SUMOylation. En face confocal microscopy revealed increases in nonnuclear p53 expression, nitrotyrosine staining, and apoptosis in aortic EC located in d-flow areas in wild-type mice, but these effects were significantly decreased in p53−/− mice. We propose a novel mechanism for p53 SUMOylation mediated by the PKCζ–PIASy interaction during d-flow–mediated EC apoptosis, which has potential relevance to early events of atherosclerosis.
RNA polymerase III drives alternative splicing of the potassium channel–interacting protein contributing to brain complexity and neurodegeneration
Authors: Massone Sara , Vassallo Irene , Castelnuovo Manuele , Fiorino Gloria , Gatta Elena , Robello Mauro , Borghi Roberta , Tabaton Massimo , Russo Claudio , Dieci Giorgio , Cancedda Ranieri , Pagano Aldo
Published: May 2011

Alternative splicing generates protein isoforms that are conditionally or differentially expressed in specific tissues. The discovery of factors that control alternative splicing might clarify the molecular basis of biological and pathological processes. We found that IL1-α−dependent up-regulation of 38A, a small ribonucleic acid (RNA) polymerase III–transcribed RNA, drives the synthesis of an alternatively spliced form of the potassium channel–interacting protein (KCNIP4). The alternative KCNIP4 isoform cannot interact with the γ-secretase complex, resulting in modification of γ-secretase activity, amyloid precursor protein processing, and increased secretion of β-amyloid enriched in the more toxic Aβ x-42 species. Notably, synthesis of the variant KCNIP4 isoform is also detrimental to brain physiology, as it results in the concomitant blockade of the fast kinetics of potassium channels. This alternative splicing shift is observed at high frequency in tissue samples from Alzheimer’s disease patients, suggesting that RNA polymerase III cogenes may be upstream determinants of alternative splicing that significantly contribute to homeostasis and pathogenesis in the brain.
Caveolin-1–eNOS signaling promotes p190RhoGAP-A nitration and endothelial permeability
Authors: Siddiqui M. Rizwan , Komarova Yulia A. , Vogel Stephen M. , Gao Xiaopei , Bonini Marcelo G. , Rajasingh Johnson , Zhao You-Yang , Brovkovych Viktor , Malik Asrar B.
Published: May 2011

Endothelial barrier function is regulated by adherens junctions (AJs) and caveolae-mediated transcellular pathways. The opening of AJs that is observed in caveolin-1−/− (Cav-1−/−) endothelium suggests that Cav-1 is necessary for AJ assembly or maintenance. Here, using endothelial cells isolated from Cav-1−/− mice, we show that Cav-1 deficiency induced the activation of endothelial nitric oxide synthase (eNOS) and the generation of nitric oxide (NO) and peroxynitrite. We assessed S-nitrosylation and nitration of AJ-associated proteins to identify downstream NO redox signaling targets. We found that the GTPase-activating protein (GAP) p190RhoGAP-A was selectively nitrated at Tyr1105, resulting in impaired GAP activity and RhoA activation. Inhibition of eNOS or RhoA restored AJ integrity and diminished endothelial hyperpermeability in Cav-1−/− mice. Thrombin, a mediator of increased endothelial permeability, also induced nitration of p120-catenin–associated p190RhoGAP-A. Thus, eNOS-dependent nitration of p190RhoGAP-A represents a crucial mechanism for AJ disassembly and resultant increased endothelial permeability.
SH3YL1 regulates dorsal ruffle formation by a novel phosphoinositide-binding domain
Authors: Hasegawa Junya , Tokuda Emi , Tenno Takeshi , Tsujita Kazuya , Sawai Haruko , Hiroaki Hidekazu , Takenawa Tadaomi , Itoh Toshiki
Published: May 2011

Reversible interactions between cytosolic proteins and membrane lipids such as phosphoinositides play important roles in membrane morphogenesis driven by actin polymerization. In this paper, we identify a novel lipid-binding module, which we call the SYLF domain (after the SH3YL1, Ysc84p/Lsb4p, Lsb3p, and plant FYVE proteins that contain it), that is highly conserved from bacteria to mammals. SH3YL1 (SH3 domain containing Ysc84-like 1) strongly bound to phosphatidylinositol 3,4,5-triphosphate (PI(3,4,5)P3) and several D5-phosphorylated phosphoinositides through its SYLF domain and was localized to circular dorsal ruffles induced by platelet-derived growth factor stimulation. Interestingly, SHIP2 (the PI(3,4,5)P3 5-phosphatase, src-homology 2–containing inositol-5-phosphatase 2) was identified as a binding partner of SH3YL1, and knockdown of these proteins significantly suppressed dorsal ruffle formation. Phosphatidylinositol 3,4-bisphosphate (PI(3,4)P2), which is mainly synthesized from PI(3,4,5)P3 by the action of SHIP2, was enriched in dorsal ruffles, and PI(3,4)P2 synthesis strongly correlated with formation of the circular membrane structure. These results provide new insight into the molecular mechanism of dorsal ruffle formation and its regulation by phosphoinositide metabolism.
Disturbed flow: p53 SUMOylation in the turnover of endothelial cells
Authors: Takabe Wakako , Alberts-Grill Noah , Jo Hanjoong
Published: May 2011

Disturbed blood flow induces apoptosis of vascular endothelial cells, which causes atherosclerosis. In this issue, Heo et al. (2011. J. Cell Biol. doi:10.1083/jcb.201010051) sheds light on p53’s role in this phenomenon. Disturbed flow induces peroxynitrite production, which activates protein kinase C ζ and it’s binding to the E3 SUMO (small ubiquitin-like modifier) ligase PIASy (protein inhibitor of activated STATy). This leads to p53 SUMOylation and its export to the cytosol, where it binds to the antiapoptotic protein Bcl-2 to induce apoptosis.
Lens intracellular hydrostatic pressure is generated by the circulation of sodium and modulated by gap junction coupling
Authors: Gao Junyuan , Sun Xiurong , Moore Leon C. , White Thomas W. , Brink Peter R. , Mathias Richard T.
Published: May 2011

We recently modeled fluid flow through gap junction channels coupling the pigmented and nonpigmented layers of the ciliary body. The model suggested the channels could transport the secretion of aqueous humor, but flow would be driven by hydrostatic pressure rather than osmosis. The pressure required to drive fluid through a single layer of gap junctions might be just a few mmHg and difficult to measure. In the lens, however, there is a circulation of Na+ that may be coupled to intracellular fluid flow. Based on this hypothesis, the fluid would cross hundreds of layers of gap junctions, and this might require a large hydrostatic gradient. Therefore, we measured hydrostatic pressure as a function of distance from the center of the lens using an intracellular microelectrode-based pressure-sensing system. In wild-type mouse lenses, intracellular pressure varied from ∼330 mmHg at the center to zero at the surface. We have several knockout/knock-in mouse models with differing levels of expression of gap junction channels coupling lens fiber cells. Intracellular hydrostatic pressure in lenses from these mouse models varied inversely with the number of channels. When the lens’ circulation of Na+ was either blocked or reduced, intracellular hydrostatic pressure in central fiber cells was either eliminated or reduced proportionally. These data are consistent with our hypotheses: fluid circulates through the lens; the intracellular leg of fluid circulation is through gap junction channels and is driven by hydrostatic pressure; and the fluid flow is generated by membrane transport of sodium.
Ligand-binding domain subregions contributing to bimodal agonism in cyclic nucleotide–gated channels
Authors: Wong Wai-Fung , Chan Kerry S.C. , Michaleski Matthew S. , Haesler Adam , Young Edgar C.
Published: May 2011

Cyclic nucleotide–gated (CNG) channels bind cGMP or cAMP in a cytoplasmic ligand–binding domain (BD), and this binding typically increases channel open probability (Po) without inducing desensitization. However, the catfish CNGA2 (fCNGA2) subtype exhibits bimodal agonism, whereby steady-state Po increases with initial cGMP-binding events (“pro” action) up to a maximum of 0.4, but decreases with subsequent cGMP-binding events (“con” action) occurring at concentrations >3 mM. We sought to clarify if low pro-action efficacy was either necessary or sufficient for con action to operate. To find BD residues responsible for con action or low pro-action efficacy or both, we constructed chimeric CNG channels: subregions of the fCNGA2 BD were substituted with corresponding sequence from the rat CNGA4 BD, which does not support con action. Constructs were expressed in frog oocytes and tested by patch clamp of cell-free membranes. For nearly all BD elements, we found at least one construct where replacing that element preserved robust con action, with a ratio of steady-state conductances, g(10 mM cGMP)/g(3 mM cGMP) < 0.75. When all of the BD sequence C terminal of strand β6 was replaced, g(10 mM cGMP)/g(3 mM cGMP) was increased to 0.95 ± 0.05 (n = 7). However, this apparent attenuation of con action could be explained by an increase in the efficacy of pro action for all agonists, controlled by a conserved “phosphate-binding cassette” motif that contacts ligand; this produces high Po values that are less sensitive to shifts in gating equilibrium. In contrast, substituting a single valine in the N-terminal helix αA abolished con action (g(30 mM cGMP)/g(3 mM cGMP) increased to 1.26 ± 0.24; n = 7) without large increases in pro-action efficacy. Our work dissociates the two functional features of low pro-action efficacy and con action, and moreover identifies a separate structural determinant for each.
Ion access pathway to the transmembrane pore in P2X receptor channels
Authors: Kawate Toshimitsu , Robertson Janice L. , Li Mufeng , Silberberg Shai D. , Swartz Kenton J.
Published: May 2011

P2X receptors are trimeric cation channels that open in response to the binding of adenosine triphosphate (ATP) to a large extracellular domain. The x-ray structure of the P2X4 receptor from zebrafish (zfP2X4) receptor reveals that the extracellular vestibule above the gate opens to the outside through lateral fenestrations, providing a potential pathway for ions to enter and exit the pore. The extracellular region also contains a void at the central axis, providing a second potential pathway. To investigate the energetics of each potential ion permeation pathway, we calculated the electrostatic free energy by solving the Poisson-Boltzmann equation along each of these pathways in the zfP2X4 crystal structure and a homology model of rat P2X2 (rP2X2). We found that the lateral fenestrations are energetically favorable for monovalent cations even in the closed-state structure, whereas the central pathway presents strong electrostatic barriers that would require structural rearrangements to allow for ion accessibility. To probe ion accessibility along these pathways in the rP2X2 receptor, we investigated the modification of introduced Cys residues by methanethiosulfonate (MTS) reagents and constrained structural changes by introducing disulfide bridges. Our results show that MTS reagents can permeate the lateral fenestrations, and that these become larger after ATP binding. Although relatively small MTS reagents can access residues in one of the vestibules within the central pathway, no reactive positions were identified in the upper region of this pathway, and disulfide bridges that constrain movements in that region do not prevent ion conduction. Collectively, these results suggest that ions access the pore using the lateral fenestrations, and that these breathe as the channel opens. The accessibility of ions to one of the chambers in the central pathway likely serves a regulatory function.
An electrostatic potassium channel opener targeting the final voltage sensor transition
Authors: Börjesson Sara I. , Elinder Fredrik
Published: May 2011

Free polyunsaturated fatty acids (PUFAs) modulate the voltage dependence of voltage-gated ion channels. As an important consequence thereof, PUFAs can suppress epileptic seizures and cardiac arrhythmia. However, molecular details for the interaction between PUFA and ion channels are not well understood. In this study, we have localized the site of action for PUFAs on the voltage-gated Shaker K channel by introducing positive charges on the channel surface, which potentiated the PUFA effect. Furthermore, we found that PUFA mainly affects the final voltage sensor movement, which is closely linked to channel opening, and that specific charges at the extracellular end of the voltage sensor are critical for the PUFA effect. Because different voltage-gated K channels have different charge profiles, this implies channel-specific PUFA effects. The identified site and the pharmacological mechanism will potentially be very useful in future drug design of small-molecule compounds specifically targeting neuronal and cardiac excitability.
A kinetic analysis of protein transport through the anthrax toxin channel
Authors: Basilio Daniel , Kienker Paul K. , Briggs Stephen W. , Finkelstein Alan
Published: May 2011

Anthrax toxin is composed of three proteins: a translocase heptameric channel, (PA63)7, formed from protective antigen (PA), which allows the other two proteins, lethal factor (LF) and edema factor (EF), to translocate across a host cell’s endosomal membrane, disrupting cellular homeostasis. (PA63)7 incorporated into planar phospholipid bilayer membranes forms a channel capable of transporting LF and EF. Protein translocation through the channel can be driven by voltage on a timescale of seconds. A characteristic of the translocation of LFN, the N-terminal 263 residues of LF, is its S-shaped kinetics. Because all of the translocation experiments reported in the literature have been performed with more than one LFN molecule bound to most of the channels, it is not clear whether the S-shaped kinetics are an intrinsic characteristic of translocation kinetics or are merely a consequence of the translocation in tandem of two or three LFNs. In this paper, we show both in macroscopic and single-channel experiments that even with only one LFN bound to the channel, the translocation kinetics are S shaped. As expected, the translocation rate is slower with more than one LFN bound. We also present a simple electrodiffusion model of translocation in which LFN is represented as a charged rod that moves subject to both Brownian motion and an applied electric field. The cumulative distribution of first-passage times of the rod past the end of the channel displays S-shaped kinetics with a voltage dependence in agreement with experimental data.
How to make predictions about future infectious disease risks
Authors: Woolhouse Mark
Published: May 2011

Formal, quantitative approaches are now widely used to make predictions about the likelihood of an infectious disease outbreak, how the disease will spread, and how to control it. Several well-established methodologies are available, including risk factor analysis, risk modelling and dynamic modelling. Even so, predictive modelling is very much the ‘art of the possible’, which tends to drive research effort towards some areas and away from others which may be at least as important. Building on the undoubted success of quantitative modelling of the epidemiology and control of human and animal diseases such as AIDS, influenza, foot-and-mouth disease and BSE, attention needs to be paid to developing a more holistic framework that captures the role of the underlying drivers of disease risks, from demography and behaviour to land use and climate change. At the same time, there is still considerable room for improvement in how quantitative analyses and their outputs are communicated to policy makers and other stakeholders. A starting point would be generally accepted guidelines for ‘good practice’ for the development and the use of predictive models.
A historical synopsis of farm animal disease and public policy in twentieth century Britain
Authors: Woods Abigail
Published: May 2011

The diseases suffered by British livestock, and the ways in which they were perceived and managed by farmers, vets and the state, changed considerably over the course of the twentieth century. This paper documents and analyses these changes in relation to the development of public policy. It reveals that scientific knowledge and disease demographics cannot by themselves explain the shifting boundaries of state responsibility for animal health, the diseases targeted and the preferred modes of intervention. Policies were shaped also by concerns over food security and the public's health, the state of the national and livestock economy, the interests and expertise of the veterinary profession, and prevailing agricultural policy. This paper demonstrates how, by precipitating changes to farming and trading practices, public policy could sometimes actually undermine farm animal health. Animal disease can therefore be viewed both as a stimulus to, and a consequence of, twentieth century public policy.
The development, regulation and use of biopesticides for integrated pest management
Authors: Chandler David , Bailey Alastair S. , Tatchell G. Mark , Davidson Gill , Greaves Justin , Grant Wyn P.
Published: May 2011

Over the past 50 years, crop protection has relied heavily on synthetic chemical pesticides, but their availability is now declining as a result of new legislation and the evolution of resistance in pest populations. Therefore, alternative pest management tactics are needed. Biopesticides are pest management agents based on living micro-organisms or natural products. They have proven potential for pest management and they are being used across the world. However, they are regulated by systems designed originally for chemical pesticides that have created market entry barriers by imposing burdensome costs on the biopesticide industry. There are also significant technical barriers to making biopesticides more effective. In the European Union, a greater emphasis on Integrated Pest Management (IPM) as part of agricultural policy may lead to innovations in the way that biopesticides are regulated. There are also new opportunities for developing biopesticides in IPM by combining ecological science with post-genomics technologies. The new biopesticide products that will result from this research will bring with them new regulatory and economic challenges that must be addressed through joint working between social and natural scientists, policy makers and industry.
The relationship between lay and technical views of
Escherichia coli
O157 risk
Authors: Strachan N. J. C. , Hunter C. J. , Jones C. D. R. , Wilson R. S. , Ethelberg S. , Cross P. , Williams A. P. , MacRitchie L. , Rotariu O. , Chadwick D.
Published: May 2011

Here, we bring together and contrast lay (accessible primarily through social science methodologies) and technical (via risk assessment and epidemiological techniques) views of the risk associated with the
Escherichia coli
O157 pathogen using two case study areas in the Grampian region of Scotland, and North Wales. Epidemiological risk factors of contact with farm animals, visiting farms or farm fields and having a private water supply were associated with postcode districts of higher than average disease incidence in the human population. However, this was not the case for the epidemiological risk factor of consumption of beef burgers, which was independent of disease incidence in the postcode district of residence. The proportion of the population expressing a high knowledge of
E. coli
O157 was greatest in high-incidence disease districts compared with low-incidence areas (17% cf. 7%). This supports the hypothesis that in high-disease-incidence areas, residents are regularly exposed to information about the disease through local cases, the media, local social networks, etc. or perhaps that individuals are more likely to be motivated to find out about it. However, no statistically significant difference was found between high- and low-incidence postcode districts in terms of the proportion of the population expressing a high likelihood of personal risk of infection (10% cf. 14%), giving a counterintuitive difference between the technical (epidemiological and quantitative microbiological risk assessment (QMRA)) and the lay assessment of
E. coli
O157 risk. This suggests that lay evaluations of
E. coli
O157 risk reflect intuitive and experience-based estimates of the risk rather than probabilistic estimates. A generally strong correspondence was found in terms of the rank order given to potential infection pathways, with environment and foodborne infection routes dominating when comparing public understanding with technical modelling results. Two general conclusions follow from the work. First, that integrative research incorporating both lay and technical views of risk is required in order that informed decisions can be made to handle or treat the risk by the groups concerned (e.g. the public, policy makers/risk managers, etc.). Second, when communicating risk, for example, through education programmes, it is important that this process is two-way with risk managers (e.g. including Food Standards Agency officials and communications team, public health infection control and environmental health officers) both sharing information with the public and stakeholder groups, as well as incorporating public knowledge, values and context (e.g. geographical location) into risk-management decisions.
Learning from history, predicting the future: the UK Dutch elm disease outbreak in relation to contemporary tree disease threats
Authors: Potter Clive , Harwood Tom , Knight Jon , Tomlinson Isobel
Published: May 2011

Expanding international trade and increased transportation are heavily implicated in the growing threat posed by invasive pathogens to biodiversity and landscapes. With trees and woodland in the UK now facing threats from a number of disease systems, this paper looks to historical experience with the Dutch elm disease (DED) epidemic of the 1970s to see what can be learned about an outbreak and attempts to prevent, manage and control it. The paper draws on an interdisciplinary investigation into the history, biology and policy of the epidemic. It presents a reconstruction based on a spatial modelling exercise underpinned by archival research and interviews with individuals involved in the attempted management of the epidemic at the time. The paper explores what, if anything, might have been done to contain the outbreak and discusses the wider lessons for plant protection. Reading across to present-day biosecurity concerns, the paper looks at the current outbreak of ramorum blight in the UK and presents an analysis of the unfolding epidemiology and policy of this more recent, and potentially very serious, disease outbreak. The paper concludes by reflecting on the continuing contemporary relevance of the DED experience at an important juncture in the evolution of plant protection policy.
Endemic cattle diseases: comparative epidemiology and governance
Authors: Carslake David , Grant Wyn , Green Laura E. , Cave Jonathan , Greaves Justin , Keeling Matt , McEldowney John , Weldegebriel Habtu , Medley Graham F.
Published: May 2011

Cattle are infected by a community of endemic pathogens with different epidemiological properties that invoke different managerial and governmental responses. We present characteristics of pathogens that influence their ability to persist in the UK, and describe a qualitative framework of factors that influence the political response to a livestock disease. We develop simple transmission models for three pathogens (bovine viral diarrhoea virus, bovine herpesvirus and
Mycobacterium avium
spp.
paratuberculosis
) using observed cattle movements, and compare the outcomes to an extensive dataset. The results demonstrate that the epidemiology of the three pathogens is determined by different aspects of within- and between-farm processes, which has economic, legal and political implications for control. We consider how these pathogens, and
Mycobacterium bovis
(the agent of bovine tuberculosis), may be classified by the process by which they persist and by their political profile. We further consider the dynamic interaction of these classifications with pathogen prevalence and with the action taken by the government.
Frameworks for risk communication and disease management: the case of Lyme disease and countryside users
Authors: Quine Christopher P. , Barnett Julie , Dobson Andrew D. M. , Marcu Afrodita , Marzano Mariella , Moseley Darren , O'Brien Liz , Randolph Sarah E. , Taylor Jennifer L. , Uzzell David
Published: May 2011

Management of zoonotic disease is necessary if countryside users are to gain benefit rather than suffer harm from their activities, and to avoid disproportionate reaction to novel threats. We introduce a conceptual framework based on the pressure–state–response model with five broad responses to disease incidence. Influencing public behaviour is one response and requires risk communication based on an integration of knowledge about the disease with an understanding of how publics respond to precautionary advice. A second framework emphasizes how risk communication involves more than information provision and should address dimensions including points-of-intervention over time, place and audience. The frameworks are developed by reference to tick-borne Lyme borreliosis (also known as Lyme disease), for which informed precautionary behaviour is particularly relevant. Interventions to influence behaviour can be directed by knowledge of spatial and temporal variation of tick abundance, what constitutes risky behaviour, how people respond to information of varying content, and an understanding of the social practices related to countryside use. The frameworks clarify the response options and help identify who is responsible for risk communication. These aspects are not consistently understood, and may result in an underestimation of the role of land-based organizations in facilitating appropriate precautionary behaviour.
Uncertainties in the governance of animal disease: an interdisciplinary framework for analysis
Authors: Fish Robert , Austin Zoe , Christley Robert , Haygarth Philip M. , Heathwaite Louise A. , Latham Sophia , Medd William , Mort Maggie , Oliver David M. , Pickup Roger , Wastling Jonathan M. , Wynne Brian
Published: May 2011

Uncertainty is an inherent feature of strategies to contain animal disease. In this paper, an interdisciplinary framework for representing strategies of containment, and analysing how uncertainties are embedded and propagated through them, is developed and illustrated. Analysis centres on persistent, periodic and emerging disease threats, with a particular focus on cryptosporidiosis, foot and mouth disease and avian influenza. Uncertainty is shown to be produced at strategic, tactical and operational levels of containment, and across the different arenas of disease prevention, anticipation and alleviation. The paper argues for more critically reflexive assessments of uncertainty in containment policy and practice. An interdisciplinary approach has an important contribution to make, but is absent from current real-world containment policy.