bluuebunny/crossref_metadata_2025 huggingface dataset:
Corruption, Automobility Cultures, and Road Traffic Deaths: The Perfect Storm in Rapidly Motorizing Countries?
Authors: Wells Peter , Beynon Malcolm J
Published: October 2011

This paper explores the hitherto neglected combined contribution of automobility cultures and corruption to prevailing death and injury rates from road traffic, with an emphasis on developing countries. Automobility cultures are argued to be crucial to real-world death and injury rates. The paper then argues that indices of public corruption may be taken as a more general proxy for the extent of traffic rule observance and risky behaviours by all classes of road user. Data on relative corruption at the national level are compared with data on road traffic deaths—both reported and adjusted. The latter seek to account for potential underreporting and definitional differences. The paper concludes that policy needs to be sensitized to local cultures, and to extend beyond issues related to the engineering of cars or infrastructures if social attitudes are to be changed, and the rate of deaths and injuries reduced.
Using fistulated sheep to compare in sacco and in vitro rumen degradation of selected feeds
Authors: Chaudhry Abdul Shakoor , Mohamed Ruba A. I.
Published: October 2011

Despite its beneficial role in almost all feed evaluation systems, the in sacco method is inconsistent and labour intensive in estimating the degradation of ruminant feeds. This study compared a rumen fluid-based in vitro method with the in sacco method to estimate degradation of 12 feeds comprising six concentrates and six grasses representing three fields during two seasons of winter and spring. Three feed groups (n = 4) were formed by using two grasses (one per season) and two concentrates. These feeds were incubated alongside blanks, in duplicate, for various hours either in sacco in three fistulated sheep or in vitro by using rumen fluid from the same sheep over three periods using two separate 3 × 3 Latin square designs. The in sacco and in vitro data were statistically compared for the effects of sheep, feed group and period on degradation at each incubation time within each method. The degradation data were fitted exponentially to derive water soluble (a), insoluble (b) and degradation rate (c) constants to estimate effective degradability at rumen outflow rate of 0.02 (P0.02) for each feed in each method. These values were statistically compared for variations within and between feed types for each method. The sheep, group and period did not differ significantly (P > 0.05) for feed degradation at most incubation times within any of these two methods. The in vitro method was able to mimic the in sacco degradation of feeds, although the absolute in vitro values were always lower than the in sacco values. The higher in sacco degradation for almost all feeds were partly attributed to the much greater losses of these feeds during their washing with water at 0 h. The in vitro method did identify significant differences (P < 0.05) in dry matter or crude protein degradations between and within different concentrates and grasses in parallel to the in sacco method. The ranking of feeds was comparable for these methods. The in vitro method can be used in parallel to the in sacco method to estimate degradation of various feeds. However, there is a need for coordinated studies to improve the prediction ability of the in vitro method for its adoption to routinely estimate the degradation of ruminant feeds.
Predicting post-fire hillslope erosion in forest lands of the western United States
Authors: Miller Mary Ellen , MacDonald Lee H. , Robichaud Peter R. , Elliot William J.
Published: October 2011

Many forests and their associated water resources are at increasing risk from large and severe wildfires due to high fuel accumulations and climate change. Extensive fuel treatments are being proposed, but it is not clear where such treatments should be focussed. The goals of this project were to: (1) predict potential post-fire erosion rates for forests and shrublands in the western United States to help prioritise fuel treatments; and (2) assess model sensitivity and accuracy. Post-fire ground cover was predicted using historical fire weather data and the First Order Fire Effects Model. Parameter files from the Disturbed Water Erosion Prediction Project (WEPP) were combined with GeoWEPP to predict post-fire erosion at the hillslope scale. Predicted median annual erosion rates were 0.1–2 Mg ha–1 year–1 for most of the intermountain west, ~10–40 Mg ha–1 year–1 for wetter areas along the Pacific Coast and up to 100 Mg ha–1 year–1 for north-western California. Sensitivity analyses showed the predicted erosion rates were predominantly controlled by the amount of precipitation rather than surface cover. The limited validation dataset showed a reasonable correlation between predicted and measured erosion rates (R2 = 0.61), although predictions were much less than measured values. Our results demonstrate the feasibility of predicting post-fire erosion rates on a large scale. The validation and sensitivity analysis indicated that the predictions are most useful for prioritising fuel reduction treatments on a local rather than interregional scale, and they also helped identify model improvements and research needs.
Holocene dynamics of the Arctic's largest ice shelf
Authors: Antoniades Dermot , Francus Pierre , Pienitz Reinhard , St-Onge Guillaume , Vincent Warwick F.
Published: October 2011

Ice shelves in the Arctic lost more than 90% of their total surface area during the 20th century and are continuing to disintegrate rapidly. The significance of these changes, however, is obscured by the poorly constrained ontogeny of Arctic ice shelves. Here we use the sedimentary record behind the largest remaining ice shelf in the Arctic, the Ward Hunt Ice Shelf (Ellesmere Island, Canada), to establish a long-term context in which to evaluate recent ice-shelf deterioration. Multiproxy analysis of sediment cores revealed pronounced biological and geochemical changes in Disraeli Fiord in response to the formation of the Ward Hunt Ice Shelf and its fluctuations through time. Our results show that the ice shelf was absent during the early Holocene and formed 4,000 years ago in response to climate cooling. Paleoecological data then indicate that the Ward Hunt Ice Shelf remained stable for almost three millennia before a major fracturing event that occurred ∼1,400 years ago. After reformation ∼800 years ago, freshwater was a constant feature of Disraeli Fiord until the catastrophic drainage of its epishelf lake in the early 21st century.
Heightened uterine mammalian target of rapamycin complex 1 (mTORC1) signaling provokes preterm birth in mice
Authors: Hirota Yasushi , Cha Jeeyeon , Yoshie Mikihiro , Daikoku Takiko , Dey Sudhansu K.
Published: October 2011

Although preterm delivery is a major global health issue, its causes and underlying mechanism remain elusive. Using mutant mice, mimicking aspects of human preterm birth, we show here that uterine decidual senescence early in pregnancy via heightened mammalian target of rapamycin complex 1 (mTORC1) signaling is a significant contributor of preterm birth and fetal death, and that these adverse phenotypes are rescued by a low dose of rapamycin, an inhibitor of mTORC1 signaling. This role of mTORC1 signaling in determining the timing of birth in mice may help us better understand the mechanism of the timing of birth in humans and develop new and improved strategies to combat the global problem of preterm birth.
Perinatal antidepressant exposure alters cortical network function in rodents
Authors: Simpson Kimberly L. , Weaver Kristin J. , de Villers-Sidani Etienne , Lu Jordan Y.-F. , Cai Zhengwei , Pang Yi , Rodriguez-Porcel Federico , Paul Ian A. , Merzenich Michael , Lin Rick C. S.
Published: October 2011

Serotonin (5-HT) plays a key role in early brain development, and manipulation of 5-HT levels during this period can have lasting neurobiological and behavioral consequences. It is unclear how perinatal exposure to drugs, such as selective serotonin reuptake inhibitors (SSRIs), impacts cortical neural network function and what mechanism(s) may elicit the disruption of normal neuronal connections/interactions. In this article, we report on cortical wiring organization after pre- and postnatal exposure to the SSRI citalopram. We show that manipulation of 5-HT during early development in both in vitro and in vivo models disturbs characteristic chemoarchitectural and electrophysiological brain features, including changes in raphe and callosal connections, sensory processing, and myelin sheath formation. Also, drug-exposed rat pups exhibit neophobia and disrupted juvenile play behavior. These findings indicate that 5-HT homeostasis is required for proper brain maturation and that fetal/infant exposure to SSRIs should be examined in humans, particularly those with developmental dysfunction, such as autism.
Mechanism for long-term memory formation when synaptic strengthening is impaired
Authors: Radwanska Kasia , Medvedev Nikolay I. , Pereira Grace S. , Engmann Olivia , Thiede Nina , Moraes Marcio F. D. , Villers Agnes , Irvine Elaine E. , Maunganidze Nicollette S. , Pyza Elżbieta M. , Ris Laurence , Szymańska Magda , Lipiński Michał , Kaczmarek Leszek , Stewart Michael G. , Giese K. Peter
Published: October 2011

Long-term memory (LTM) formation has been linked with functional strengthening of existing synapses and other processes including de novo synaptogenesis. However, it is unclear whether synaptogenesis can contribute to LTM formation. Here, using α-calcium/calmodulin kinase II autophosphorylation-deficient (T286A) mutants, we demonstrate that when functional strengthening is severely impaired, contextual LTM formation is linked with training-induced PSD95 up-regulation followed by persistent generation of multiinnervated spines, a type of synapse that is characterized by several presynaptic terminals contacting the same postsynaptic spine. Both PSD95 up-regulation and contextual LTM formation in T286A mutants required signaling by the mammalian target of rapamycin (mTOR). Furthermore, we show that contextual LTM resists destabilization in T286A mutants, indicating that LTM is less flexible when synaptic strengthening is impaired. Taken together, we suggest that activation of mTOR signaling, followed by overexpression of PSD95 protein and synaptogenesis, contributes to formation of invariant LTM when functional strengthening is impaired.
Crucial role of a shared extracellular loop in apamin sensitivity and maintenance of pore shape of small-conductance calcium-activated potassium (SK) channels
Authors: Weatherall Kate L. , Seutin Vincent , Liégeois Jean-François , Marrion Neil V.
Published: October 2011

Activation of small-conductance calcium (Ca
2+
)-dependent potassium (K
Ca
2) channels (herein called “SK”) produces membrane hyperpolarization to regulate membrane excitability. Three subtypes (SK1–3) have been cloned and are distributed throughout the nervous system, smooth muscle, and heart. It is difficult to discern the physiological role of individual channel subtypes as most blockers or enhancers do not discriminate between subtypes. The archetypical blocker apamin displays some selectivity between SK channel subtypes, with SK2 being the most sensitive, followed by SK3 and then SK1. Sensitivity of SK1 is species specific, with the human isoform being blocked by the toxin, whereas the rat is not. Mutation studies have identified residues within the outer pore that suggest apamin blocks by an allosteric mechanism. Apamin also uses a residue within the S3–S4 extracellular loop to produce a high-sensitivity block. We have identified that a 3-amino acid motif within this loop regulates the shape of the channel pore. This motif is required for binding and block by apamin, suggesting that a change in pore shape underlies allosteric block. This motif is absent in rat SK1, explaining why it is insensitive to block by apamin. The overlapping distribution of SK channel subtype expression suggests that native heteromeric channels may be common. We show that the S3–S4 loop of one subunit overlaps the outer pore of the adjacent subunit, with apamin interacting with both regions. This arrangement provides a unique binding site for each combination of SK subunits within a coassembled channel that may be targeted to produce blockers specific for heteromeric SK channels.
Epigenome characterization at single base-pair resolution
Authors: Henikoff Jorja G. , Belsky Jason A. , Krassovsky Kristina , MacAlpine David M. , Henikoff Steven
Published: October 2011

We have combined standard micrococcal nuclease (MNase) digestion of nuclei with a modified protocol for constructing paired-end DNA sequencing libraries to map both nucleosomes and subnucleosome-sized particles at single base-pair resolution throughout the budding yeast genome. We found that partially unwrapped nucleosomes and subnucleosome-sized particles can occupy the same position within a cell population, suggesting dynamic behavior. By varying the time of MNase digestion, we have been able to observe changes that reflect differential sensitivity of particles, including the eviction of nucleosomes. To characterize DNA-binding features of transcription factors, we plotted the length of each fragment versus its position in the genome, which defined the minimal protected region of each factor. This process led to the precise mapping of protected and exposed regions at and around binding sites, and also determination of the degree to which they are flanked by phased nucleosomes and subnucleosome-sized particles. Our protocol and mapping method provide a general strategy for epigenome characterization, including nucleosome phasing and dynamics, ATP-dependent nucleosome remodelers, and transcription factors, from a single-sequenced sample.
Molecular differentiation of historic phage-type 80/81 and contemporary epidemic
Staphylococcus aureus
Authors: DeLeo Frank R. , Kennedy Adam D. , Chen Liang , Wardenburg Juliane Bubeck , Kobayashi Scott D. , Mathema Barun , Braughton Kevin R. , Whitney Adeline R. , Villaruz Amer E. , Martens Craig A. , Porcella Stephen F. , McGavin Martin J. , Otto Michael , Musser James M. , Kreiswirth Barry N.
Published: October 2011

Staphylococcus
aureus
is a bacterial pathogen known to cause infections in epidemic waves. One such epidemic was caused by a clone known as phage-type 80/81, a penicillin-resistant strain that rose to world prominence in the late 1950s. The molecular underpinnings of the phage-type 80/81 outbreak have remained unknown for decades, nor is it understood why related
S. aureus
clones became epidemic in hospitals in the early 1990s. To better understand the molecular basis of these epidemics, we sequenced the genomes of eight
S. aureus
clinical isolates representative of the phage-type 80/81 clone, the Southwest Pacific clone [a community-associated methicillin-resistant
S. aureus
(MRSA) clone], and contemporary
S. aureus
clones, all of which are genetically related and belong to the same clonal complex (CC30). Genome sequence analysis revealed that there was coincident divergence of these clones from a recent common ancestor, a finding that resolves controversy about the evolutionary history of the lineage. Notably, we identified nonsynonymous SNPs in genes encoding accessory gene regulator C (
agrC
) and α-hemolysin (
hla
)—molecules important for
S. aureus
virulence—that were present in virtually all contemporary CC30 hospital isolates tested. Compared with the phage-type 80/81 and Southwest Pacific clones, contemporary CC30 hospital isolates had reduced virulence in mouse infection models, the result of SNPs in
agrC
and
hla
. We conclude that
agr
and
hla
(along with penicillin resistance) were essential for world dominance of phage-type 80/81
S. aureus
, whereas key SNPs in contemporary CC30 clones restrict these pathogens to hospital settings in which the host is typically compromised.
Signal transducer and activator of transcription-6 (STAT6) inhibition suppresses renal cyst growth in polycystic kidney disease
Authors: Olsan Erin E. , Mukherjee Sambuddho , Wulkersdorfer Beatrix , Shillingford Jonathan M. , Giovannone Adrian J. , Todorov Gueorgui , Song Xuewen , Pei York , Weimbs Thomas
Published: October 2011

Autosomal-dominant (AD) polycystic kidney disease (PKD) is a leading cause of renal failure in the United States, and currently lacks available treatment options to slow disease progression. Mutations in the gene coding for polycystin-1 (PC1) underlie the majority of cases but the function of PC1 has remained poorly understood. We have previously shown that PC1 regulates the transcriptional activity of signal transducer and activator of transcription-6 (STAT6). Here we show that STAT6 is aberrantly activated in cyst-lining cells in PKD mouse models. Activation of the STAT6 pathway leads to a positive feedback loop involving auto/paracrine signaling by IL13 and the IL4/13 receptor. The presence of IL13 in cyst fluid and the overexpression of IL4/13 receptor chains suggests a mechanism of sustained STAT6 activation in cysts. Genetic inactivation of STAT6 in a PKD mouse model leads to significant inhibition of proliferation and cyst growth and preservation of renal function. We show that the active metabolite of leflunomide, a drug approved for treatment of arthritis, inhibits STAT6 in renal epithelial cells. Treatment of PKD mice with this drug leads to amelioration of the renal cystic disease similar to genetic STAT6 inactivation. These results suggest STAT6 as a promising drug target for treatment of ADPKD.
Algorithms to automatically quantify the geometric similarity of anatomical surfaces
Authors: Boyer Doug M. , Lipman Yaron , St. Clair Elizabeth , Puente Jesus , Patel Biren A. , Funkhouser Thomas , Jernvall Jukka , Daubechies Ingrid
Published: October 2011

We describe approaches for distances between pairs of two-dimensional surfaces (embedded in three-dimensional space) that use local structures and global information contained in interstructure geometric relationships. We present algorithms to automatically determine these distances as well as geometric correspondences. This approach is motivated by the aspiration of students of natural science to understand the continuity of form that unites the diversity of life. At present, scientists using physical traits to study evolutionary relationships among living and extinct animals analyze data extracted from carefully defined anatomical correspondence points (landmarks). Identifying and recording these landmarks is time consuming and can be done accurately only by trained morphologists. This necessity renders these studies inaccessible to nonmorphologists and causes phenomics to lag behind genomics in elucidating evolutionary patterns. Unlike other algorithms presented for morphological correspondences, our approach does not require any preliminary marking of special features or landmarks by the user. It also differs from other seminal work in computational geometry in that our algorithms are polynomial in nature and thus faster, making pairwise comparisons feasible for significantly larger numbers of digitized surfaces. We illustrate our approach using three datasets representing teeth and different bones of primates and humans, and show that it leads to highly accurate results.
Differential regulation of self-reactivity discriminates between IgG+human circulating memory B cells and bone marrow plasma cells
Authors: Scheid Johannes F. , Mouquet Hugo , Kofer Juliane , Yurasov Sergey , Nussenzweig Michel C. , Wardemann Hedda
Published: October 2011

Long-term humoral immunity is maintained by the formation of high-affinity class-switched memory B cells and long-lived antibody-secreting plasma cells. In healthy humans, a substantial fraction of IgG-positive memory B cells express self-reactive and polyreactive IgG antibodies that frequently develop by somatic mutations. Whether self- and polyreactive IgG-secreting B cells are also tolerated in the long-lived plasma cell pool is not known. To address this question, we cloned and expressed the Ig genes from 177 IgG-producing bone marrow plasma cells of four healthy donors. All antibodies were highly mutated but the frequency of self- and polyreactive IgG antibodies was significantly lower than that found in circulating memory B cells. The data suggest that in contrast to the development of memory B cells, entry into the bone marrow plasma cell compartment requires previously unappreciated selective regulation by mechanisms that limit the production of self- and polyreactive serum IgG antibodies.
Tetherin is a key effector of the antiretroviral activity of type I interferon in vitro and in vivo
Authors: Liberatore Rachel A. , Bieniasz Paul D.
Published: October 2011

Tetherin (Bst-2 CD317) is a cell-surface protein whose expression is induced by IFNα. Although tetherin expression causes the retention of retrovirus particles on the surface of infected cells, it is not known whether tetherin inhibits retroviral replication or pathogenesis in vivo. Mutation of tetherin antagonists often has little effect on retroviral replication in vitro, and, although tetherin can reduce the yield of extracellular viral particles, some studies suggest that tetherin actually enhances direct cell-to-cell viral transmission. We generated tetherin-deficient mice to determine the effect of this protein on murine retrovirus replication and pathogenesis. We find that tetherin markedly inhibits the replication of Moloney murine leukemia virus (Mo-MLV) and is required for the antiretroviral activity of IFNα to be fully manifested in vitro. Surprisingly, Mo-MLV replication and disease progression was not significantly different in WT and tetherin-deficient mice, but this finding was explained by the fact that Mo-MLV infection did not induce detectable tetherin expression on candidate target cells in vivo. Indeed, IFNα induction was required to reveal the anti–Mo-MLV activity of tetherin in vivo. Moreover, LP-BM5, an MLV strain that has been demonstrated to induce immune activation and IFNα expression, achieved higher levels of viremia and induced exaggerated pathology in tetherin-deficient mice. These data indicate that tetherin is a bona fide antiviral protein and can reduce retroviral replication and disease in vivo.
Isotopic paleoecology of Clovis mammoths from Arizona
Authors: Metcalfe Jessica Z. , Longstaffe Fred J. , Ballenger Jesse A. M. , Haynes C. Vance
Published: October 2011

The causes of megafaunal extinctions in North America have been widely debated but remain poorly understood. Mammoths (
Mammuthus
spp.) in the American Southwest were hunted by Clovis people during a period of rapid climate change, just before the regional onset of Younger Dryas cooling and mammoth extirpation. Thus, these mammoths may provide key insights into late Pleistocene extinction processes. Here we reconstruct the seasonal diet and climatic conditions experienced by mammoths in the San Pedro Valley of Arizona, using the carbon (
13
C/
12
C) and oxygen (
18
O/
16
O) isotope compositions of tooth enamel. These records suggest that Clovis mammoths experienced a warm, dry climate with sufficient summer rainfall to support seasonal C
4
plant growth. Monsoon intensity may have been reduced relative to the preceding time period, but there is no isotopic evidence for severe drought. However, it is possible that the “Clovis drought”, inferred from stratigraphic evidence, occurred suddenly at the end of the animals’ lives and thus was not recorded in the enamel isotopic compositions. Unlike mammoths that lived before the Last Glacial Maximum, Clovis mammoths regularly increased C
4
grass consumption during summer, probably seeking seasonally green grasslands farther from the river valley. This predictable seasonal behavior may have made mammoths easier to locate by Clovis hunters. Furthermore, Clovis mammoths probably had no previous experience of such sudden climatic change as is believed to have occurred at the time of their extinction.
Functional test of
Brassica
self-incompatibility modifiers in
Arabidopsis thaliana
Authors: Kitashiba Hiroyasu , Liu Pei , Nishio Takeshi , Nasrallah June B. , Nasrallah Mikhail E.
Published: October 2011

The self-incompatibility (SI) system of the Brassicaceae is based on allele-specific interactions among haplotypes of the
S
locus. In all tested self-incompatible Brassicaceae, the
S
haplotype encompasses two linked genes, one encoding the
S
-locus receptor kinase (SRK), a transmembrane kinase displayed at the surface of stigma epidermal cells, and the other encoding its ligand, the
S
-locus cysteine-rich (SCR) protein, which is localized in the pollen coat. Transfer of the two genes to self-fertile
Arabidopsis thaliana
allowed the establishment of robust SI in several accessions, indicating that the signaling cascade triggered by this receptor–ligand interaction and the resulting inhibition of “self” pollen by the stigma have been maintained in extant
A. thaliana
. Based on studies in
Brassica
species, the membrane-tethered kinase MLPK, the ARM repeat-containing U-box protein ARC1, and the exocyst subunit Exo70A1 have been proposed to function as components of an SI signaling cascade. Here we tested the role of these molecules in the SI response of
A. thaliana SRK-SCR
plants. We show that the
A. thaliana ARC1
ortholog is a highly decayed pseudogene. We also show that, unlike reports in
Brassica
, inactivation of the
MLPK
ortholog
AtAPK1b
and overexpression of
Exo70A1
neither abolish nor weaken SI in
A. thaliana SRK-SCR
plants. These results do not support a role for these molecules in the SI response of
A. thaliana
.
Actin filament severing by cofilin is more important for assembly than constriction of the cytokinetic contractile ring
Authors: Chen Qian , Pollard Thomas D.
Published: October 2011

We created two new mutants of fission yeast cofilin to investigate why cytokinesis in many organisms depends on this small actin-binding protein. These mutant cofilins bound actin monomers normally, but bound and severed ADP-actin filaments much slower than wild-type cofilin. Cells depending on mutant cofilins condensed nodes, precursors of the contractile ring, into clumps rather than rings. Starting from clumped nodes, mutant cells slowly assembled rings from diverse intermediate structures including spiral strands containing actin filaments and other contractile ring proteins. This process in mutant cells depended on α-actinin. These slowly assembled contractile rings constricted at a normal rate but with more variability, indicating ring constriction is not very sensitive to defects in severing by cofilin. Computer simulations of the search-capture-pull and release model of contractile ring formation predicted that nodes clump when the release step is slow, so cofilin severing of actin filament connections between nodes likely contributes to the release step.
Phosphorylation at serine 331 is required for Aurora B activation
Authors: Petsalaki Eleni , Akoumianaki Tonia , Black Elizabeth J. , Gillespie David A.F. , Zachos George
Published: October 2011

Aurora B kinase activity is required for successful cell division. In this paper, we show that Aurora B is phosphorylated at serine 331 (Ser331) during mitosis and that phosphorylated Aurora B localizes to kinetochores in prometaphase cells. Chk1 kinase is essential for Ser331 phosphorylation during unperturbed prometaphase or during spindle disruption by taxol but not nocodazole. Phosphorylation at Ser331 is required for optimal phosphorylation of INCENP at TSS residues, for Survivin association with the chromosomal passenger complex, and for complete Aurora B activation, but it is dispensable for Aurora B localization to centromeres, for autophosphorylation at threonine 232, and for association with INCENP. Overexpression of Aurora BS331A, in which Ser331 is mutated to alanine, results in spontaneous chromosome missegregation, cell multinucleation, unstable binding of BubR1 to kinetochores, and impaired mitotic delay in the presence of taxol. We propose that Chk1 phosphorylates Aurora B at Ser331 to fully induce Aurora B kinase activity. These results indicate that phosphorylation at Ser331 is an essential mechanism for Aurora B activation.
Drosophila ATM and ATR have distinct activities in the regulation of meiotic DNA damage and repair
Authors: Joyce Eric F. , Pedersen Michael , Tiong Stanley , White-Brown Sanese K. , Paul Anshu , Campbell Shelagh D. , McKim Kim S.
Published: October 2011

Ataxia telangiectasia–mutated (ATM) and ataxia telangiectasia–related (ATR) kinases are conserved regulators of cellular responses to double strand breaks (DSBs). During meiosis, however, the functions of these kinases in DSB repair and the deoxyribonucleic acid (DNA) damage checkpoint are unclear. In this paper, we show that ATM and ATR have unique roles in the repair of meiotic DSBs in Drosophila melanogaster. ATR mutant analysis indicated that it is required for checkpoint activity, whereas ATM may not be. Both kinases phosphorylate H2AV (γ-H2AV), and, using this as a reporter for ATM/ATR activity, we found that the DSB repair response is surprisingly dynamic at the site of DNA damage. γ-H2AV is continuously exchanged, requiring new phosphorylation at the break site until repair is completed. However, most surprising is that the number of γ-H2AV foci is dramatically increased in the absence of ATM, but not ATR, suggesting that the number of DSBs is increased. Thus, we conclude that ATM is primarily required for the meiotic DSB repair response, which includes functions in DNA damage repair and negative feedback control over the level of programmed DSBs during meiosis.
Graphs and multi-graphs in homogeneous 3-manifolds with isometry groups of dimension 4
Authors: Peñafiel Carlos
Published: October 2011

We study the existence of multi-graphs which are immersed in

E
3

(
κ
,
τ
)

E^3(\kappa ,\tau )

, having constant mean curvature

H
H

, where

E
3

(
κ
,
τ
)

E^3(\kappa ,\tau )

is a homogeneous, simply connected 3-manifold whose isometry group has dimension 4.
Silencing and Heterologous Expression of ppo-2 Indicate a Specific Function of a Single Polyphenol Oxidase Isoform in Resistance of Dandelion (Taraxacum officinale) Against Pseudomonas syringae pv. tomato
Authors: Richter Carolin , Dirks Mareike E. , Gronover Christian Schulze , Prüfer Dirk , Moerschbacher Bruno M.
Published: October 2011

Dandelion (Taraxacum officinale) possesses an unusually high degree of disease resistance. As this plant exhibits high polyphenol oxidase (PPO) activity and PPO have been implicated in resistance against pests and pathogens, we analyzed the potential involvement of five PPO isoenzymes in the resistance of dandelion against Botrytis cinerea and Pseudomonas syringae pv. tomato. Only one PPO (ppo-2) was induced during infection, and ppo-2 promoter and β-glucuronidase marker gene fusions revealed strong induction of the gene surrounding lesions induced by B. cinerea. Specific RNAi silencing reduced ppo-2 expression only, and concomitantly increased plant susceptibility to P. syringae pv. tomato. At 4 days postinoculation, P. syringae pv. tomato populations were strongly increased in the ppo-2 RNAi lines compared with wild-type plants. When the dandelion ppo-2 gene was expressed in Arabidopsis thaliana, a plant having no PPO gene, active protein was formed and protein extracts of the transgenic plants exhibited substrate-dependent antimicrobial activity against P. syringae pv. tomato. These results clearly indicate a strong contribution of a specific, single PPO isoform to disease resistance. Therefore, we propose that specific PPO isoenzymes be included in a new family of pathogenesis-related (PR) proteins.
Molecular Characterization, Ecology, and Epidemiology of a Novel Tymovirus inAsclepias viridisfrom Oklahoma
Authors: Min Byoung-Eun , Feldman Tracy S. , Ali Akhtar , Wiley Graham , Muthukumar Vijay , Roe Bruce A. , Roossinck Marilyn , Melcher Ulrich , Palmer Michael W. , Nelson Richard S.
Published: October 2011

Native virus–plant interactions require more understanding and their study will provide a basis from which to identify potential sources of emerging destructive viruses in crops. A novel tymovirus sequence was detected in Asclepias viridis (green milkweed), a perennial growing in a natural setting in the Tallgrass Prairie Preserve (TGPP) of Oklahoma. It was abundant within and frequent among A. viridis plants and, to varying extents, within other dicotyledonous and one grass (Panicum virgatum) species obtained from the TGPP. Extracts from A. viridis containing the sequence were infectious to a limited number of species. The virus genome was cloned and determined to be closely related to Kennedya yellow mosaic virus. The persistence of the virus within the Oklahoma A. viridis population was monitored for five successive years. Virus was present in a high percentage of plants within representative areas of the TGPP in all years and was spreading to additional plants. Virus was present in regions adjacent to the TGPP but not in plants sampled from central and south-central Oklahoma. Virus was present in the underground caudex of the plant during the winter, suggesting overwintering in this tissue. The RNA sequence encoding the virus coat protein varied considerably between individual plants (≈3%), likely due to drift rather than selection. An infectious clone was constructed and the virus was named Asclepias asymptomatic virus (AsAV) due to the absence of obvious symptoms on A. viridis.
Pancreatic Resections for Solid or Cystic Pancreatic Masses in Children
Authors: Muller C.O. , Guérin F. , Goldzmidt D. , Fouquet V. , Franchi‐Abella S. , Fabre M. , Branchereau S. , Martelli H. , Gauthier F.
Published: October 2011

Objectives:

The aim of the study was to assess the diagnosis and management of solid pancreatic neoplasm in children and the type of surgical treatment, focusing on short‐ and long‐term outcomes.

Methods:

We retrospectively reviewed the charts of all children who had undergone pancreatic resection for suspicion of pancreatic tumor in Kremlin Bicêtre Hospital, Paris, between 1986 and 2008. We studied the symptoms at diagnosis, the type of surgery, and the short‐ and long‐term morbidity and mortality.

Results:

Of 18 patients identified, there were 7 pseudopapillary tumors, 3 neuroblastomas, 2 rhabdomyosarcomas, 1 acinar cell carcinoma, 1 endocrine cell carcinoma, 1 renal angiomyolipoma, and 3 pancreatic cysts. Symptoms at diagnosis were abdominal trauma, abdominal mass, and jaundice. Operative procedures were duodenopancreatectomy (11), mid‐pancreatic resections (2), splenopancreatectomy (2), distal pancreatectomy (1), and tumorectomy (2). There were no deaths related to surgery. The postoperative morbidity rate was 45%, including 2 cases of fistula (11%) occurring after a mid‐pancreatic resection and a pancreaticoduodenectomy. The median follow‐up was 4.2 years (range 2–11). There was no diabetes mellitus, but there was 1 case of fat diet intolerance requiring pancreatic enzyme substitution. All of the children had a growth curve within normal limits.

Conclusions:

In this experience, pancreatic resections have proven to be a safe and efficient procedure, with low long‐term morbidity, for the treatment of tumoral and selected nontumoral pancreatic masses.
A hybrid zone and bidirectional introgression between two catadromous species: Australian bassMacquaria novemaculeataand estuary perchMacquaria colonorum
Authors: Shaddick K. , Burridge C. P. , Jerry D. R. , Schwartz T. S. , Truong K. , Gilligan D. M. , Beheregaray L. B.
Published: October 2011

The presence and distribution of hybrid individuals and the existence of a hybrid zone between the catadromous Australian bassMacquaria novemaculeataand estuary perchMacquaria colonorumwere investigated throughout the range of both species in Australia. Bayesian analyses and genotypic simulations identified 140 putative hybrids (11·5% of the total sample) with varying levels of introgression. Most hybrids were observed in an area extending from the Snowy River to the Albert River suggesting a hybrid zone in the eastern Bass Strait region. Sixteen hybrids, however, were found outside this zone, possibly reflecting the movement of hybrid offspring between estuaries or their inadvertent release during fish stocking programmes. Biparental backcrossing was found to occur suggesting that hybrids were fertile. These results have implications for the management of the extensive stocking programme inM. novemaculeataand for understanding the potential role of habitat degradation and reduced water flow in facilitating hybridization in species with migratory life histories.
Diet and niche overlap of southern populations of brill Scophthalmus rhombus and turbot Scophthalmus maximus
Authors: Vinagre C. , Silva A. , Lara M. , Cabral H. N.
Published: October 2011

The diets of adult brill Scophthalmus rhombus and turbot Scophthalmus maximus from the Portuguese coast relied mostly on fishes. There was a higher diversity of food items compared to their northern counterparts, and several of the identified prey are the first records of these species, including a brown alga, echinoderms, nematodes, oligochaetes, gastropods, bivalves and various fish species. The diet of the two species was significantly different and niche overlap was low.
The efficacy of field techniques for obtaining and storing blood samples from fishes
Authors: Clark T. D. , Donaldson M. R. , Drenner S. M. , Hinch S. G. , Patterson D. A. , Hills J. , Ives V. , Carter J. J. , Cooke S. J. , Farrell A. P.
Published: October 2011

Prompted by the dramatic increase in the use of blood analyses in fisheries research and monitoring, this study investigated the efficacy of common field techniques for sampling and storing blood from fishes. Three questions were addressed: (1) Do blood samples taken via rapid caudal puncture (the ‘grab‐and‐stab’ technique) yield similar results for live v. sacrificed groups of fishes? (2) Do rapidly obtained caudal blood samples accurately represent blood properties of fishes prior to capture? (3) Does storage of whole blood in an ice slurry for a working day (8·5 h) modify the properties of the plasma? It was shown that haematocrit, plasma ions, metabolites, stress hormones and sex hormones of caudal blood samples were statistically similar when taken from live v. recently sacrificed groups of adult coho salmon Oncorhynchus kisutch. Moreover, this study confirmed by using paired blood samples from cannulated O. kisutch that blood acquired through the caudal puncture technique (mean ±s.e. 142 ± 26 s after capture) was representative of fish prior to capture. Long‐term (8·5 h) cold storage of sockeye salmon Oncorhynchus nerka whole blood caused significant decreases in plasma potassium and chloride, and a significant increase in plasma glucose. Previous research has suggested that these changes largely result from net movements of ions and molecules between the plasma and erythrocytes, movements that can occur within minutes of storage. Thus, blood samples from fishes should be centrifuged as quickly as practicable in the field for separation of plasma and erythrocytes to prevent potentially misleading data.
The effect of staggered administration of zinc sulfate on the pharmacokinetics of oral cephalexin
Authors: Ding Yi , Jia Yan‐Yan , Li Fan , Liu Wen‐Xing , Lu Cheng‐Tao , Zhu Yan‐Rong , Yang Jing , Ding Li‐Kun , Yang Lin , Wen Ai‐Dong
Published: October 2011

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Zinc supplementation is an important intervention against mortality from infectious disease.

• Many patients using zinc supplementation will also be prescribed antimicrobials at some time.

• Recently, an inhibitory effect of zinc on the absorption of β‐lactam antibiotics has been demonstrated in animal studies, but there has been no clinical assessment of this drug–nutrient interaction.

WHAT THIS STUDY ADDS

• Zinc sulfate dosing significantly impaired the bioavailability and decreased T > MIC of cephalexin in healthy volunteers, which might lead to a clinical failure.

• The dosing recommendation is that zinc sulfate can be safely administered 3 h after a cephalexin dose.

AIMS To investigate the effect of zinc sulfate on pharmacokinetics of cephalexin when administered concurrently or at strategically spaced dosing times designed to avoid the potential interaction in healthy volunteers.

METHODS In this study, all subjects (n= 12) were randomized to receive the following four treatments, separated by a wash‐out period of 7 days: cephalexin 500 mg alone, concomitantly with zinc 250 mg, 3 h after zinc 250 mg or 3 h before zinc 250 mg.

RESULTS All subjects completed the study safely. Zinc supplements administered concurrently with cephalexin significantly decreased the peak serum concentration (Cmax), area under the plasma concentration–time curve from zero to infinity (AUC0–∞) and the time for which the plasma concentration of the drug remained above the minimal inhibitory concentration of the pathogenic organism (T > MIC) of cephalexin [mean percentage decrease (95% confidence intervals) of 31.05% (22.09–40.01%), 27.40% (18.33–36.47%) and 22.33% (12.51–32.16%), respectively; P < 0.05] compared with administration of cephalexin alone. Also, administration of zinc 3 h before cephalexin decreased the Cmax, AUC0–∞ and T > MIC of the drug compared with administration of cephalexin alone [mean percentage decrease (95% confidence intervals) of 11.48% (3.40–19.55%), 18.12% (9.63–26.60%) and 23.75% (14.30–33.20%), respectively; P < 0.05]. In contrast, the pharmacokinetics of cephalexin was not notably altered by administration of zinc 3 h after cephalexin dosing (P > 0.05).

CONCLUSIONS The significant interaction between zinc and cephalexin might affect the clinical outcome of cephalexin therapy. The dosing recommendation is that zinc sulfate can be safely administered 3 h after a cephalexin dose.
‘Have you had your bowl of rice?’: a qualitative study of eating patterns in older Taiwanese adults
Authors: Chen Su‐Hui , Shao Jung‐hua
Published: October 2011

Aim.  The purpose of this study was to explore the eating patterns of older Taiwanese adults.

Background.  The number of older adults in Taiwan is increasing and they have been shown to have poor nutritional status. However, little attention has been directed at uncovering eating patterns among this population as part of their aging process.

Design.  To explore older Taiwanese adults’ eating patterns, a qualitative research design was chosen.

Methods.  Eating patterns of older Taiwanese adults were explored in narrative interviews conducted from April–June 2007. Of the 156 participants who participated in a larger correlational, cross‐sectional study, 58 agreed to answer one open‐ended question about their eating patterns. All interviews were tape‐recorded, transcribed verbatim and analysed using qualitative content analysis.

Results.  Analysis of interview data identified three major categories: ‘eating and old age’, ‘eating and faith’ and ‘eating and family harmony’. Subcategories in each major category included ‘achieving good health’, ‘upholding old customs’; ‘depending on God/fate’, ‘enjoying later life’; and ‘following the family eating rules’, ‘self‐sacrificing for the family’, respectively.

Conclusions.  Older Taiwanese people adopt eating patterns not only for health reasons, but also in keeping with their faith and the need to preserve family harmony. This research supports and contributes to understanding the eating patterns of older adults in Taiwan.

Relevance to clinical practice.  Disseminating these findings may increase nurses’ awareness of nutrition issues in older adults. Older Taiwanese adults’ eating patterns centred on family values. Nursing intervention programmes, therefore, should address key family members involved in food preparation. Our findings also suggest that older adults followed old customs in their eating practices. Nurses are suggested to acknowledge and respect these customs as special food needs of older adults.
Ontogenetic conflicts and rank reversals in two Mediterranean oak species: implications for coexistence
Authors: Pérez‐Ramos Ignacio M. , Urbieta Itziar R. , Zavala Miguel A. , Marañón Teodoro
Published: October 2011

1. In heterogeneous environments, species segregate spatially in response to selective abiotic and biotic filters occurring throughout plant ontogeny. Ontogenetic conflicts in recruitment may lead to spatially discordant patterns of regeneration among microhabitats with different plant cover. In addition, species differing in seed size may be subjected to opposing ecological and evolutionary pressures throughout the life cycle of the plant.

2. We used a multi‐stage demographic approach aimed at characterizing the main stage‐specific probabilities of recruitment (seed survival, seed germination, seedling emergence and survival during the first 3 years of life) in two Mediterranean oak species coexisting at southern Spain. We calibrated linear and nonlinear likelihood models for each of these consecutive life history stages and calculated overall probabilities of recruitment along a wide range of plant cover and seed size variation.

3. Seed predation and seedling mortality over the dry season were the most limiting processes for the two studied oak species. However, species ranking diverged substantially through the life history stages considered in this study due to different ontogenetic trends among species.

4. At the intraspecific level, recruitment‐driving processes during the seed and the seedling stages showed opposing tendencies along the explored range of plant cover and seed size. Thus, small‐sized acorns and open areas were favoured for the seed stage, whereas large acorns and dense microhabitats did for the seedling stage.

5. The existence of opposing selective pressures on seed mass and their differential influence on the two studied oak species determined the occurrence of species‐specific optimal seed sizes (small acorns for Quercus canariensis vs. acorns of large or intermediate size for Quercus suber).

6. The spatial patterns predicted by our overall‐recruitment models provided some evidence of regeneration niche partitioning in the two coexisting oak species, supporting their current distribution patterns as saplings and adults at the study area.

7. Synthesis. We conclude that within‐ and among‐species differences through plant ontogeny, arising from species differential response to microhabitat heterogeneity and seed size variation, could be of great importance for oak species niche segregation, driving stand dynamics and spatial pattern distribution along the landscape. The information provided by this study could be also applied to optimize management and restoration programmes since it has enabled us to identify the most favourable conditions and traits for recruitment in oak species that exhibit serious constraints for natural regeneration.
Loss of AtPDR11, a plasma membrane‐localized ABC transporter, confers paraquat tolerance in Arabidopsis thaliana
Authors: Xi Jing , Xu Ping , Xiang Cheng‐Bin
Published: October 2011

Paraquat is one of the most widely used herbicides in the world. However, no paraquat transporter has been isolated in plants. Here, we describe paraquat‐tolerant mutant pqt24‐1, isolated from an activation‐tagging library on the basis of its tolerance to 2 μm paraquat in the seedling stage. Molecular analysis revealed that the T‐DNA was inserted in the 13th exon of At1g66950, which encodes AtPDR11, a member of the ATP‐binding cassette transporter superfamily. As a result, AtPDR11 was knocked out in the mutant. Loss‐of‐function mutations of AtPDR11 led to reduced paraquat accumulation in plant cells. In addition, the AtPDR11 protein was specifically localized in the plasmalemma, suggesting AtPDR11 as a potential transporter of paraquat. This conclusion was supported by kinetic analysis of paraquat import. Further studies showed that the transcript level of AtPDR11 could be strongly induced by paraquat and other abiotic stresses including H2O2, indicating possible up‐regulation of AtPDR11 expression by oxidative stress signaling. Thus, our data suggest that paraquat is an opportunistic substrate of AtPDR11 and the enhanced paraquat tolerance of pqt24‐1 is due to reduced uptake of paraquat into plant cells.