bluuebunny/crossref_metadata_2025 huggingface dataset:
ASalmonellaTyphimurium phage type (PT) U320 outbreak in England, 2008: continuation of a trend involving ready-to-eat products
Authors: BOXALL N. S. , ADAK G. K. , DE PINNA E. , GILLESPIE I. A.
Published: January 2011

In March 2008, the Health Protection Agency in England conducted a retrospective case-control study to investigate the cause of 179 cases of the newly recognized, fully antimicrobial-sensitiveSalmonellaTyphimurium PT U320. Forty-three symptomatic laboratory-confirmed case-patients and 84 asymptomatic location-matched controls were interviewed by telephone about exposures in the 3 days prior to illness or interview. Multivariate logistic analysis indicated consumption of pre-packaged egg sandwiches (odds ratio 3·29, 95% confidence interval 1·19–9·09) was independently associated with illness. Eight of the 15 case-patients who consumed egg sandwiches did so from retail chain A (53·3%) whereas none of the eight controls consumed similar sandwiches (χ2=7·20,P⩽0·01). A review of the pre-packaged egg sandwich ingredients suggested this outbreak was probably caused by exposure to an ingredient common to pre-packaged sandwiches and prepared salads but we established a definitive epidemiological link with only the former. Short shelf-life, product diversity and investigation lag hinder epidemiological investigations of such popular products, providing continued challenges for food safety enforcement of freshly prepared produce.
Reported early family environment covaries with menarcheal age as a function of polymorphic variation in estrogen receptor-α
Authors: Manuck Stephen B. , Craig Anna E. , Flory Janine D. , Halder Indrani , Ferrell Robert E.
Published: January 2011

Age at menarche, a sentinel index of pubertal maturation, was examined in relation to early family relationships (conflict, cohesion) and polymorphic variation in the gene encoding estrogen receptor-α (ESR1) in a midlife sample of 455 European American women. Consistent with prior literature, women who reported being raised in families characterized by close interpersonal relationships and little conflict tended to reach menarche at a later age than participants reared in families lacking cohesion and prone to discord. Moreover, this association was moderated byESR1variation, such that quality of the family environment covaried positively with menarcheal age among participants homozygous for minor alleles of the twoESR1polymorphisms studied here (rs9304799, rs2234693), but not among women of otherESR1genotypes. In addition, (a) family relationship variables were unrelated toESR1variation, and (b) genotype-dependent effects of childhood environment on age at menarche could not be accounted for by personality traits elsewhere shown to explain heritable variation in reported family conflict and cohesion. These findings are consistent with theories of differential susceptibility to environmental influence, as well as the more specific hypothesis (by Belsky) that girls differ genetically in their sensitivity to rearing effects on pubertal maturation.
Quality of early family relationships and the timing and tempo of puberty: Effects depend on biological sensitivity to context
Authors: Ellis Bruce J. , Shirtcliff Elizabeth A. , Boyce W. Thomas , Deardorff Julianna , Essex Marilyn J.
Published: January 2011

Guided by evolutionary–developmental theories of biological sensitivity to context and reproductive development, the current research examined the interactive effects of early family environments and psychobiologic reactivity to stress on the subsequent timing and tempo of puberty. As predicted by the theory, among children displaying heightened biological sensitivity to context (i.e., higher stress reactivity), higher quality parent–child relationships forecast slower initial pubertal tempo and later pubertal timing, whereas lower quality parent–child relationships forecast the opposite pattern. No such effects emerged among less context-sensitive children. Whereas sympathetic nervous system reactivity moderated the effects of parent–child relationships on both breast/genital and pubic hair development, adrenocortical activation only moderated the effect on pubic hair development. The current results build on previous research documenting what family contexts predict variation in pubertal timing by demonstrating for whom those contexts matter. In addition, the authors advance a new methodological approach for assessing pubertal tempo using piecewise growth curve analysis.
Hippocampal volume and sensitivity to maternal aggressive behavior: A prospective study of adolescent depressive symptoms
Authors: Whittle Sarah , Yap Marie B. H. , Sheeber Lisa , Dudgeon Paul , Yücel Murat , Pantelis Christos , Simmons Julian G. , Allen Nicholas B.
Published: January 2011

It has been suggested that biological factors confer increased sensitivity to environmental influences on depressive symptoms during adolescence, a crucial time for the onset of depressive disorders. Given the critical role of the hippocampus in sensitivity to stress and processing of contextual aspects of the environment, investigation of its role in determining sensitivity to environmental context seems warranted. This study prospectively examined hippocampal volume as a measure of sensitivity to the influence of aggressive maternal behavior on change in depressive symptoms from early to midadolescence. The interaction between aggressive maternal behavior and hippocampal volume was found to predict change in depressive symptoms. Significant sex differences also emerged, whereby only for girls were larger bilateral hippocampal volumes more sensitive to the effects of maternal aggressive behavior, particularly with respect to experiencing the protective effects of low levels of maternal aggressiveness. These findings help elucidate the complex relationships between brain structure, environmental factors such as maternal parenting style, and sensitivity to (i.e., risk for, and protection from) the emergence of depression during this life stage. Given that family context risk factors are modifiable, our findings suggest the potential utility of targeted parenting interventions for the prevention and treatment of adolescent depressive disorder.
Enhancing infant attachment security: An examination of treatment efficacy and differential susceptibility
Authors: Cassidy Jude , Woodhouse Susan S. , Sherman Laura J. , Stupica Brandi , Lejuez C. W.
Published: January 2011

This randomized controlled trial examined (a) the efficacy of a brief intervention designed to increase the rate of secure infant attachment, (b) the differential susceptibility hypothesis, and (c) whether maternal attachment styles moderated the expected Treatment × Irritability interaction in predicting infant attachment outcomes. Although there was no main effect of treatment, a significant Treatment × Irritability interaction revealed intervention effects for the highly irritable infants only, thus supporting one of two predictions of the differential susceptibility hypothesis: highly irritable infants would have disproportionately better outcomes than moderately irritable infants in better conditions (i.e., with intervention). When separate analyses were conducted with maternal attachment styles, we found significant three-way interactions among treatment, irritability, and each of the examined maternal attachment style dimensions (i.e., secure–fearful and dismissing–preoccupied). Specifically, with more secure mothers, beneficial effects of intervention emerged for highly irritable infants. For more dismissing mothers, the results revealed support for both predictions of the differential susceptibility hypothesis: highly irritable infants, compared to moderately irritable infants, werebothmore likely to be secure with interventionandless likely to be secure when in the control group. It is interesting that, for more preoccupied mothers, a treatment effect emerged only formoderatelyirritable infants. We discuss the implications of these findings for the differential susceptibility hypothesis as well as for early intervention.
Brain and personality bases of insensitivity to infant cues in neglectful mothers: An event-related potential study
Authors: Rodrigo María José , León Inmaculada , Quiñones Ileana , Lage Agustín , Byrne Sonia , Bobes María Antonieta
Published: January 2011

This investigation examined the neural and personality correlates of processing infant facial expressions in mothers with substantiated neglect of a child under 5 years old. Event-related potentials (ERPs) were recorded from 14 neglectful and 14 control mothers as they viewed and categorized pictures of infant cries, laughs, and neutral faces. Maternal self-reports of anhedonia and empathy were also completed. Early (negative occipitotemporal component peaking at around 170 ms on the scalp [N170] and positive electrical potential peaking at about 200 ms [P200]) and late positive potential (LPP) components were selected. Both groups of mothers showed behavioral discrimination between the different facial expressions via reaction time and accuracy measures. Neglectful mothers did not exhibit increased N170 amplitude at temporal leads in response to viewing crying versus laughing and neutral expressions compared to control mothers. Both groups had greater P200 and LPP amplitudes at centroparietal leads in response to viewing crying versus neutral facial expressions. However, neglectful mothers displayed an overall attenuated brain response in LPP that was related to their higher scores in social anhedonia but not to their empathy scores. The ERP data suggest that the brain's failures in the early differentiation of cry stimuli and in the sustained processing of infant expressions related to social anhedonia may underlie the insensitive responding in neglectful mothers. The implications of these results for the design and evaluation of preventive interventions are discussed.
Individual differences in the development of early peer aggression: Integrating contributions of self-regulation, theory of mind, and parenting
Authors: Olson Sheryl L. , Lopez-Duran Nestor , Lunkenheimer Erika S. , Chang Hyein , Sameroff Arnold J.
Published: January 2011

This prospective longitudinal study focused on self-regulatory, social–cognitive, and parenting precursors of individual differences in children's peer-directed aggression at early school age. Participants were 199 3-year-old boys and girls who were reassessed following the transition to kindergarten (5.5–6 years). Peer aggression was assessed in preschool and school settings using naturalistic observations and teacher reports. Children's self-regulation abilities and theory of mind understanding were assessed during a laboratory visit, and parenting risk (corporal punishment and low warmth/responsiveness) was assessed using interview-based and questionnaire measures. Individual differences in children's peer aggression were moderately stable across the preschool to school transition. Preschool-age children who manifested high levels of aggressive peer interactions also showed lower levels of self-regulation and theory of mind understanding, and experienced higher levels of adverse parenting than others. Our main finding was that early corporal punishment was associated with increased levels of peer aggression across the transition from preschool to school, as was the interaction between low maternal emotional support and children's early delays in theory of mind understanding. These data highlight the need for family-directed preventive efforts during the early preschool years.
Changes in women's alcoholic, antisocial, and depressive symptomatology over 12 years: A multilevel network of individual, familial, and neighborhood influences
Authors: Buu Anne , Wang Wei , Wang Jing , Puttler Leon I. , Fitzgerald Hiram E. , Zucker Robert A.
Published: January 2011

In a sample of 273 adult women and their families, we examined the effects of women's psychopathology history, their social support, their husbands' and children's symptomatology, family stress, and neighborhood environment on their alcohol problems, antisocial behavior, and depression over a 12-year period during their 30s and early 40s. Women's alcohol problems and antisocial behavior decreased but their depression symptoms increased over time. Women's disorder history and their partners' parallel symptomatology were associated with their symptoms. For women's antisocial behavior, their own history of alcoholism and their partners' alcohol problems were also significant risk factors. Higher levels of social support were associated with lower levels of depression in women. Children's externalizing behavior was positively correlated with their mothers' alcohol problems and antisocial behavior, whereas children's internalizing behavior was positively correlated with their mothers' depression. Neighborhood residential instability was associated with higher levels of alcoholic and depressive symptomatology in women. Intervention efforts might target women with young children by improving social support, educational or professional training opportunity, access to family counseling, and neighborhood environment.
Diet cost, diet quality and socio-economic position: how are they related and what contributes to differences in diet costs?
Authors: Rydén Petra J , Hagfors Linda
Published: January 2011

Objective

To examine diet costs in relation to dietary quality and socio-economic position, and to investigate underlying reasons for differences in diet costs.

Design

Dietary intake was assessed by a 4 d food diary and evaluated using the 2005 Healthy Eating Index (HEI). National consumer food prices collected by Statistics Sweden and from two online stores/supermarkets were used to estimate diet costs.

Setting

Sweden.

Subjects

A nationally representative sample of 2160 children aged 4, 8 or 11 years.

Results

Higher scores on the HEI resulted in higher diet costs and, conversely, higher diet costs were linked to increased total HEI scores. Children who consumed the most healthy and/or expensive diets ate a more energy-dilute and varied diet compared with those who ate the least healthy and/or least expensive diets. They also consumed more fish, ready meals and fruit. Regression analysis also linked increased food costs to these food groups. There was a positive, but weak, relationship between HEI score and diet cost, parental education and parental occupation respectively.

Conclusions

Healthy eating is associated with higher diet cost in Swedish children, in part because of price differences between healthy and less-healthy foods. The cheapest and most unhealthy diets were found among those children whose parents were the least educated and had manual, low-skill occupations. Our results pose several challenges for public health policy makers, as well as for nutrition professionals, when forming dietary strategies and providing advice for macro- and microlevels in society.
A study investigating professional attitudes and confidence in providing sexuality information to prostate cancer patients
Authors: Griffiths D. , Hodgson D.A.
Published: January 2011

Purpose: Sexual dysfunction is a well-documented side effect of radical radiotherapy treatment for prostate cancer and the provision of information to patients is often a radiotherapist and assistant role. The study sought to measure the attitudes and beliefs of individuals before and after an educational intervention and establish current practice in providing sexual information.

Method: A quantitative approach with a minor qualitative element was used. A simple pre–post test questionnaire design using an adapted version of the Reynold and Magnan (2005) Sexual Attitudes and Beliefs’ Questionnaire was utilised. The educational intervention was a Reflective Learning Package (RLP).

Results: Fifty-six participants took part, a response rate of 87.5%. The data was analysed using SPSS, version 15. The RLP had a highly significant effect on improving the attitudes and beliefs of the participants (Wilcoxon test 0.000 p < 0.001). Qualitative data key themes showed lack of knowledge, confidence and embarrassment were the main barriers to giving sexuality information during the ‘first day chat’.

Conclusion: There may be a need to address the current methods of education and support of staff being prepared to perform this important role and to recognise that personal limitations may influence the individuals’ effectiveness in communicating sexuality information.
A transdiagnostic self-help guide for anxiety: two preliminary controlled trials in subclinical student samples
Authors: Dixon Clare , Mansell Warren , Rawlinson Elizabeth , Gibson Alisha
Published: January 2011

Self-help therapies, such as bibliotherapy, are becoming increasingly more available to the general population as a treatment for psychological disorders, such as depression and anxiety. However, relatively few of these self-help books are properly evaluated to test their treatment efficacy. Two studies aimed to test a new self-help book to treat fears, phobias and anxiety in order to see if symptoms of anxiety and associated symptoms, such as functioning and coping, were improved compared to baseline scores and a waiting-list control group. Study 1 adopted a minimal guided approach (experimental group:n= 25; waiting-list control group:n= 29) whereas Study 2 adopted a non-guided approach (experimental group:n= 17; waiting-list control group:n= 16). In both studies, functioning and coping were improved and the current state of phobic symptoms was reduced. The main phobia improved only when adopting a guided approach and general psychological distress only reduced when adopting a non-guided approach. These studies provide preliminary support for a modest effect in a subclinical population. The results could have good implications for the treatment of anxiety and the use of self-help methods as an additional treatment aid or as a preventative treatment.
In Brief: New faults mapped after the April 2010 Baja California earthquake
Authors: Tretkoff Ernie
Published: January 2011

High‐resolution remote imaging of ground deformation after an earthquake that occurred in Baja California on 4 April 2010 is providing researchers with new information about the complex fault structure in the region and could help improve hazard assessment for southern California. The magnitude 7.2 El Mayor‐Cucapah earthquake on 4 April 2010, the region's largest quake in more than a century, occurred along the border of the Pacific and North American tectonic plates, near the border between California and Mexico. The epicenter was located in Mexicali Valley, Baja California. Aftershocks, many of which were felt in the United States, extended to the southeast and northwest.
Data sharing: What about epidemiological cohorts?
Authors: Goldberg Marcel , Zins Marie
Published: January 2011

General-purpose population-based cohorts can be powerful scientific platforms. The Gazel Cohort Study, a French cohort of 20,000 adults followed-up since more than 20 years, was designed as an open epidemiologic laboratory, hosting more than 40 nested research projects from French and international teams.Formal rules were elaborated to define the way that the Gazel database can be accessed.One of the main problems faced by the Gazel team members is scientific recognition of their work, as the large majority of the publications come from external research groups.
Nitrones in synthetic polymer chemistry
Authors: Wong Edgar H. H. , Junkers Tanja , Barner-Kowollik Christopher
Published: January 2011

Very recently, the development of enhanced spin capturing polymerization (ESCP) and nitrone-mediated radical coupling (NMRC) reactions—based on nitrone chemistry—has opened up novel synthetic avenues in macromolecular engineering. The synthetic potential of nitrones in polymer chemistry is discussed herein.
Traditional Facial Tattoos Disrupt Face Recognition Processes
Authors: Buttle Heather , East Julie
Published: January 2011

Factors that are important to successful face recognition, such as features, configuration, and pigmentation/reflectance, are all subject to change when a face has been engraved with ink markings. Here we show that the application of facial tattoos, in the form of spiral patterns (typically associated with the Maori tradition of a Moko), disrupts face recognition to a similar extent as face inversion, with recognition accuracy little better than chance performance (2AFC). These results indicate that facial tattoos can severely disrupt our ability to recognise a face that previously did not have the pattern.
Illusory Motion Induced by Blurred Red — Blue Edges
Authors: Takahashi Kohske , Niimi Ryosuke , Watanabe Katsumi
Published: January 2011

Visual patterns consisting of a red-and-blue region with a blurry edge yield illusory motion. Eye movements over a static pattern induced illusory motion of the edge in the direction opposite to the eye movement. The illusion also takes place for patterns in motion without eye movement. The illusion suggests the effect of colour combination on the spatial perception of a blurry edge.
Fairground Rides and Spatial Updating
Authors: Land Michael F
Published: January 2011

A simple experiment with a rotating office chair demonstrates that the extent of counter-rotation we experience when imposed rotation has stopped is the same as the angular inaccuracy of pointing to a previously fixated object. This suggests that our conscious percept of rotation and the updating signal for the egocentric model we use to guide motor actions are closely related.
Phantom Arcs: Now You See Them …
Authors: Bauer Ben
Published: January 2011

A new visual illusion is reported and illustrated. The illusion, dubbed ‘phantom arcs’, survives manipulations of contrast, scale, and hue. The arcs can be seen in printed versions as well as in images displayed on CRT or LCD monitors. Data collected in an undergraduate perception class reveal that the illusion can be seen by untrained observers.
Stigma, sexual risk and desire for HIV tests in Ghana
Authors: Koku Emmanuel F.
Published: January 2011

Background: Although various HIV prevention and treatment programs have been implemented in Ghana since 2003, desire for and uptake of HIV testing is still low, owing largely to HIV-related stigma. This study examined the effect of stigma on desire for HIV testing, while controlling for socio-demographic and other influences. Method: The study used data from the 2003 Ghana Demographic and Health Survey to regress desire for an HIV test on levels of stigma while controlling for selected socio-demographic, socio-cognitive and socio-behavioural covariates. Results: The study revealed significant associations between several socio-demographic and socio-cognitive variables and the desire for an HIV test. For example, both male (adjusted odds ratio (AOR) = 0.41; 95% confidence interval (CI) = 0.24–0.72) and female (AOR = 0.62; 95% CI = 0.41–0.93) respondents in the wealthiest households, and those who know someone infected with HIV (AOR = 0.65; 95% CI = 0.43–1.00) have lower odds of desiring an HIV test. The study showed a significant but negative interaction between risky sexual behaviours and community stigma (AOR = 0.44; 95% CI = 0.19–0.67), indicating that the positive effect of risky sex on HIV testing is attenuated among females who live in communities with high levels of stigma. Conclusion: Since community-level education and risk reduction programs have demonstrable influences on reducing HIV stigma, it is imperative that the Ghana government’s ongoing anti-stigma campaigns and other HIV prevention programs recognise the role of community stigma in influencing HIV testing decisions, especially in the context of risky sexual behaviours.
Differences between African-American adolescent females with and without human papillomavirus infection
Authors: Seth Puja , Wingood Gina M. , DiClemente Ralph J. , Crosby Richard A. , Salazar Laura F. , Rose Eve S. , Sales Jessica M.
Published: January 2011

Background:An important policy question is whether high-risk populations can be identified and prioritised for human papillomavirus (HPV) immunisation. Methods: Data collection included an audio computer-assisted survey interview and testing of Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae, and HPV among 295 African-American adolescent females. Results: The results indicated that 43.1% tested positive for HPV. Logistic regression analyses indicated that HPV prevalence was not associated with other sexually transmissible infections (prevalence ratio (PR) = 0.85, 95% confidence interval (CI) = 0.51–1.41), unprotected vaginal sex (PR = 1.04, 95% CI = 0.56–1.92), having sex with an older male partner (PR = 1.12, 95% CI = 0.64–1.96), and having a casual partner (PR = 0.89, 95% CI = 0.54–1.48). Additionally, t-tests indicated that HPV prevalence was not associated with frequency of vaginal sex (t = 0.17, P = 0.87), protected sex (t = –0.16, P = 0.87), number of recent (t = 0.40, P = 0.69) or lifetime (t = 1.45, P = 0.15) sexual partners. However, those testing positive for HPV were younger (t = 1.97, P = 0.05) and reported current use of birth control pills (PR = 2.38, 95% CI = 1.00–5.63). Conclusions: It may not be possible to identify those with elevated risk of HPV acquisition. Thus, HPV vaccination, regardless of risk indicators, may be the most efficacious public health strategy.
Helping the embryo find closure
Authors: Leslie Mitch
Published: January 2011

Loss of protein from neighbors tells migrating cells they are in the vanguard.
Matthew Welch: The many branches of actin regulation
Authors: Short Ben
Published: January 2011

Welch investigates how host cells and pathogens initiate actin polymerization.
Replication protein A promotes 5′→3′ end processing during homology-dependent DNA double-strand break repair
Authors: Yan Hong , Toczylowski Thomas , McCane Jill , Chen Chinyi , Liao Shuren
Published: January 2011

Replication protein A (RPA), the eukaryotic single-strand deoxyribonucleic acid (DNA [ss-DNA])–binding protein, is involved in DNA replication, nucleotide damage repair, mismatch repair, and DNA damage checkpoint response, but its function in DNA double-strand break (DSB) repair is poorly understood. We investigated the function of RPA in homology-dependent DSB repair using Xenopus laevis nucleoplasmic extracts as a model system. We found that RPA is required for single-strand annealing, one of the homology-dependent DSB repair pathways. Furthermore, RPA promotes the generation of 3′ single-strand tails (ss-tails) by stimulating both the Xenopus Werner syndrome protein (xWRN)–mediated unwinding of DNA ends and the subsequent Xenopus DNA2 (xDNA2)–mediated degradation of the 5′ ss-tail. Purified xWRN, xDNA2, and RPA are sufficient to carry out the 5′-strand resection of DNA that carries a 3′ ss-tail. These results provide strong biochemical evidence to link RPA to a specific DSB repair pathway and reveal a novel function of RPA in the generation of 3′ ss-DNA for homology-dependent DSB repair.
Distinct ECM mechanosensing pathways regulate microtubule dynamics to control endothelial cell branching morphogenesis
Authors: Myers Kenneth A. , Applegate Kathryn T. , Danuser Gaudenz , Fischer Robert S. , Waterman Clare M.
Published: January 2011

During angiogenesis, cytoskeletal dynamics that mediate endothelial cell branching morphogenesis during vascular guidance are thought to be regulated by physical attributes of the extracellular matrix (ECM) in a process termed mechanosensing. Here, we tested the involvement of microtubules in linking mechanosensing to endothelial cell branching morphogenesis. We used a recently developed microtubule plus end–tracking program to show that specific parameters of microtubule assembly dynamics, growth speed and growth persistence, are globally and regionally modified by, and contribute to, ECM mechanosensing. We demonstrated that engagement of compliant two-dimensional or three-dimensional ECMs induces local differences in microtubule growth speed that require myosin II contractility. Finally, we found that microtubule growth persistence is modulated by myosin II–mediated compliance mechanosensing when cells are cultured on two-dimensional ECMs, whereas three-dimensional ECM engagement makes microtubule growth persistence insensitive to changes in ECM compliance. Thus, compliance and dimensionality ECM mechanosensing pathways independently regulate specific and distinct microtubule dynamics parameters in endothelial cells to guide branching morphogenesis in physically complex ECMs.
RNA polymerase I–specific subunits promote polymerase clustering to enhance the rRNA gene transcription cycle
Authors: Albert Benjamin , Léger-Silvestre Isabelle , Normand Christophe , Ostermaier Martin K. , Pérez-Fernández Jorge , Panov Kostya I. , Zomerdijk Joost C.B.M. , Schultz Patrick , Gadal Olivier
Published: January 2011

RNA polymerase I (Pol I) produces large ribosomal RNAs (rRNAs). In this study, we show that the Rpa49 and Rpa34 Pol I subunits, which do not have counterparts in Pol II and Pol III complexes, are functionally conserved using heterospecific complementation of the human and Schizosaccharomyces pombe orthologues in Saccharomyces cerevisiae. Deletion of RPA49 leads to the disappearance of nucleolar structure, but nucleolar assembly can be restored by decreasing ribosomal gene copy number from 190 to 25. Statistical analysis of Miller spreads in the absence of Rpa49 demonstrates a fourfold decrease in Pol I loading rate per gene and decreased contact between adjacent Pol I complexes. Therefore, the Rpa34 and Rpa49 Pol I–specific subunits are essential for nucleolar assembly and for the high polymerase loading rate associated with frequent contact between adjacent enzymes. Together our data suggest that localized rRNA production results in spatially constrained rRNA production, which is instrumental for nucleolar assembly.
Asymmetric distribution of Echinoid defines the epidermal leading edge during Drosophila dorsal closure
Authors: Laplante Caroline , Nilson Laura A.
Published: January 2011

During Drosophila melanogaster dorsal closure, lateral sheets of embryonic epidermis assemble an actomyosin cable at their leading edge and migrate dorsally over the amnioserosa, converging at the dorsal midline. We show that disappearance of the homophilic cell adhesion molecule Echinoid (Ed) from the amnioserosa just before dorsal closure eliminates homophilic interactions with the adjacent dorsal-most epidermal (DME) cells, which comprise the leading edge. The resulting planar polarized distribution of Ed in the DME cells is essential for the localized accumulation of actin regulators and for actomyosin cable formation at the leading edge and for the polarized localization of the scaffolding protein Bazooka/PAR-3. DME cells with uniform Ed fail to assemble a cable and protrude dorsally, suggesting that the cable restricts dorsal migration. The planar polarized distribution of Ed in the DME cells thus provides a spatial cue that polarizes the DME cell actin cytoskeleton, defining the epidermal leading edge and establishing its contractile properties.
N-WASP is required for membrane wrapping and myelination by Schwann cells
Authors: Novak Nurit , Bar Vered , Sabanay Helena , Frechter Shahar , Jaegle Martine , Snapper Scott B. , Meijer Dies , Peles Elior
Published: January 2011

During peripheral nerve myelination, Schwann cells sort larger axons, ensheath them, and eventually wrap their membrane to form the myelin sheath. These processes involve extensive changes in cell shape, but the exact mechanisms involved are still unknown. Neural Wiskott–Aldrich syndrome protein (N-WASP) integrates various extracellular signals to control actin dynamics and cytoskeletal reorganization through activation of the Arp2/3 complex. By generating mice lacking N-WASP in myelinating Schwann cells, we show that N-WASP is crucial for myelination. In N-WASP–deficient nerves, Schwann cells sort and ensheath axons, but most of them fail to myelinate and arrest at the promyelinating stage. Yet, a limited number of Schwann cells form unusually short internodes, containing thin myelin sheaths, with the occasional appearance of myelin misfoldings. These data suggest that regulation of actin filament nucleation in Schwann cells by N-WASP is crucial for membrane wrapping, longitudinal extension, and myelination.
Noether normalizations, reductions of ideals, and matroids
Authors: Brennan Joseph , Epstein Neil
Published: January 2011

We show that given a finitely generated standard graded algebra of dimension

d
d

over an infinite field, its graded Noether normalizations obey a certain kind of ‘generic exchange’, allowing one to pass between any two of them in at most

d
d

steps. We prove analogous generic exchange theorems for minimal reductions of an ideal, minimal complete reductions of a set of ideals, and minimal complete reductions of multigraded

k
k

-algebras. Finally, we unify all these results into a common axiomatic framework by introducing a new topological-combinatorial structure we call a generic matroid, which is a common generalization of a topological space and a matroid.
More about dicriticals
Authors: Abhyankar Shreeram
Published: January 2011

This paper attempts to characterize the dicritical set of a rational function which generates a special pencil at a simple point of an algebraic or arithmetical surface.
Elliptic centralizers in Weyl groups and their coinvariant representations
Authors: Reeder Mark
Published: January 2011

The centralizer

C
(
w
)

C(w)

of an elliptic element

w
w

in a Weyl group has a natural symplectic representation on the group of

w
w

-coinvariants in the root lattice. We give the basic properties of this representation, along with applications to

p
p

-adic groups—classifying maximal tori and computing inducing data in

L
L

-packets—as well as to elucidating the structure of the centralizer

C
(
w
)

C(w)

itself. We give the structure of each elliptic centralizer in

W
(

E
8

)

W(E_8)

in terms of its coinvariant representation, and we refine Springer’s theory for elliptic regular elements to give explicit complex reflections generating

C
(
w
)

C(w)

. The case where

w
w

has order three is examined in detail, with connections to mathematics of the nineteenth century. A variation of the methods recovers the subgroup

W
(

H
4

)
⊂
W
(

E
8

)

W(H_4)\subset W(E_8)

.
Endogenous and Enhanced Oxidative Cross‐Linking in Wheat Flour Mill Streams
Authors: Ramseyer Daniel D. , Bettge Arthur D. , Morris Craig F.
Published: January 2011

A better understanding of the variation in oxidative cross‐linking potential among flour mill streams can improve flour quality through the formulating of superior flour blends, and hence end‐product attributes. The purpose of this research was to study the variation of oxidative cross‐linking among 10 Miag Multomat pilot mill streams from 31 hard, soft and club wheat cultivars using Bostwick viscosity measurements. Flour slurries were made with either water alone (to measure the endogenous oxidative cross‐linking viscosity) or with added hydrogen peroxide‐peroxidase (to measure the enhanced oxidative cross‐linking viscosity). Hard cultivars tended to produce more viscous flour slurries for both water and peroxide‐peroxidase viscosity measurements in most mill streams. Mill streams with high oxidative cross‐linking potential were those with the largest differences between water and peroxide‐peroxidase viscosity including 1st Break, 1st and 2nd Middlings, and 1st Midds Redust. Conversely, mill streams 3rd Break and 4th and 5th Middlings were the least likely to form oxidative cross‐links. The ability to form oxidative cross‐links is dependent on the availability of ferulic acid and tyrosine residues. Therefore, the arabinoxylan and protein polymers in mill streams that have a high oxidative cross‐linking potential have a structure that is more conducive to forming oxidative cross‐links.
454 Genome Sequencing of Pseudoperonospora cubensis Reveals Effector Proteins with a QXLR Translocation Motif
Authors: Tian Miaoying , Win Joe , Savory Elizabeth , Burkhardt Alyssa , Held Michael , Brandizzi Federica , Day Brad
Published: January 2011

Pseudoperonospora cubensis is a biotrophic oomycete pathogen that causes downy mildew of cucurbits, a devastating foliar disease threatening cucurbit production worldwide. We sequenced P. cubensis genomic DNA using 454 pyrosequencing and obtained random genomic sequences covering approximately 14% of the genome, thus providing the first set of useful genomic sequence information for P. cubensis. Using bioinformatics approaches, we identified 32 putative RXLR effector proteins. Interestingly, we also identified 29 secreted peptides with high similarity to RXLR effectors at the N-terminal translocation domain, yet containing an R-to-Q substitution in the first residue of the translocation motif. Among these, a family of QXLR-containing proteins, designated as PcQNE, was confirmed to have a functional signal peptide and was further characterized as being localized in the plant nucleus. Internalization of secreted PcQNE into plant cells requires the QXLR-EER motif. This family has a large number of near-identical copies within the P. cubensis genome, is under diversifying selection at the C-terminal domain, and is upregulated during infection of plants, all of which are common characteristics of characterized oomycete effectors. Taken together, the data suggest that PcQNE are bona fide effector proteins with a QXLR translocation motif, and QXLR effectors are prevalent in P. cubensis. Furthermore, the massive duplication of PcQNE suggests that they might play pivotal roles in pathogen fitness and pathogenicity.
Management of Verticillium Wilt of Potato with Disease-Suppressive Green Manures and as Affected by Previous Cropping History
Authors: Larkin Robert P. , Honeycutt C. Wayne , Olanya O. Modesto
Published: January 2011

The ability of disease-suppressive rotation crops to reduce potato disease problems and increase crop productivity in a field with prior severe Verticillium wilt, as well as the potential influence of previous cropping history on disease suppression, was evaluated over three field seasons in Maine. Disease-suppressive rotations consisted of: (i) a high-glucosinolate mustard blend (‘Caliente 119’) as a mixture of white mustard (Sinapis alba) and oriental mustard (Brassica juncea) with known biofumigation potential and (ii) a sorghum-sudangrass hybrid. Each were grown as single-season green manures followed by a subsequent potato crop. These rotations were compared with a standard barley rotation and a barley rotation followed by chemical fumigation with metam sodium as controls. Both green manure rotations significantly reduced (average reductions of 25 and 18%, respectively) Verticillium wilt in the subsequent potato crop compared with the standard barley control but were not as effective as chemical fumigation (35% reduction). The mustard blend also reduced other soilborne diseases (black scurf and common scab) better than all other rotations. Mustard blend and chemical fumigation treatments increased tuber yield relative to the barley control by 12 and 18%, respectively. However, by the second rotation cycle, disease levels were high in all rotations, and only chemical fumigation resulted in substantial disease reduction (35%). Rotations also had significant effects on soil microbiology, including soil bacterial and fungal populations and microbial community characteristics based on fatty acid profiles. However, only chemical fumigation significantly reduced soil populations of Verticillium spp. and increased general soil microbial activity. Previous cropping history did not significantly affect disease reduction, tuber yield, or soil microbial communities. This research indicates the potential for using disease-suppressive rotations for managing Verticillium wilt and other soilborne diseases but also indicates that multiple years of disease-suppressive crops may be needed to substantially reduce disease in heavily infested fields.
First Report of Microcyclosporella mali Causing Sooty Blotch and Flyspeck Disease on Plum in Poland
Authors: Mirzwa-Mróz E. , Wińska-Krysiak M. , Marcinkowska J. , Gleason M. L.
Published: January 2011

Sooty blotch and flyspeck (SBFS), a disease caused by a complex of fungi, results in substantial economic losses for commercial growers of scab-resistant apple (Malus × domestica Borkh.) cultivars in Poland. However, many species causing SBFS in Poland are unidentified and sources of inoculum are uncertain. In August 2009, signs of SBFS were noted on fruit of plum (Prunus domestica L., cvs. Sweet Common Prune and Oullins Golden Gage) in orchards near Mostki in central Poland. Colonies consisted of olive green-to-black mycelial mats with few sclerotium-like bodies; infections ranged in severity from scattered spots to nearly complete coverage of the fruit surface. Ten of these colonies were isolated on potato dextrose agar (PDA). After 10 days of incubation at 22°C, total DNA was extracted; amplification of the internal transcribed spacer (ITS) region of rDNA utilized primers ITS1 and ITS4 (1). Nucleotide sequences were analyzed by ClustalW and compared with sequences in GenBank using BLAST. Sequences showed 99 to 100% homology to Microcyclosporella mali (2), which was formerly assigned as Pseudocercosporella sp. (1). Sequences from five isolates were submitted to GenBank (Accession Nos. HM101275, HM101276, HM101277, HM101278, and HM101279). Morphological characteristics–conidiogenous cells integrated, sympodial and polyblastic; conidial scars nonthickened and inconspicuous; conidia hyaline, subcylindric, narrow, straight or very slightly curved, truncate at the base and obtuse at the apex, often catenulate in simple or branched chains, with one (commonly) to five septa (12.5 × 2.6 to 50.7 × 4.0 μm)–were consistent with descriptions of M. mali (2). To fulfill Koch's postulates, each of the 10 isolates was used to inoculate three healthy apple fruit (cv. Golden Delicious) that had been previously washed under tap water and disinfested with 70% ethanol. After fruit were swabbed with cotton plugs that had been saturated with a suspension of spores in sterile distilled water (SDW), inoculated fruit were placed on filter paper that had been moistened with SDW, then sealed in foil bags and incubated at 22°C. When bags were removed 5 weeks later, dark colonies had appeared on the fruit. Isolates obtained from these colonies were morphologically identical to those used for inoculation. Control (SDW-inoculated and noninoculated) fruit that were incubated in the same manner developed no colonies. To our knowledge, this is the first report of SBFS on plum caused by M. mali in Poland; it had previously been noted as part of the SBFS complex on apple in Germany and Slovenia (2) and on apple and plum in the United States (3).

References: (1) J. C. Batzer et al. Mycologia 97:1268, 2005. (2) J. Frank et al. Persoonia 24:93, 2010. (3) J. Latinović et al. Plant Dis. 91:1685, 2007.
Risk Factors for Crop Health Under Global Change and Agricultural Shifts: A Framework of Analyses Using Rice in Tropical and Subtropical Asia as a Model
Authors: Savary S. , Mila A. , Willocquet L. , Esker P. D. , Carisse O. , McRoberts N.
Published: January 2011

Plant disease epidemiology requires expansion of its current methodological and theoretical underpinnings in order to produce full contributions to global food security and global changes. Here, we outline a framework which we applied to farmers' field survey data set on rice diseases in the tropical and subtropical lowlands of Asia. Crop health risks arise from individual diseases, as well as their combinations in syndromes. Four key drivers of agricultural change were examined: labor, water, fertilizer, and land availability that translate into crop establishment method, water shortage, fertilizer input, and fallow period duration, respectively, as well as their combinations in production situations. Various statistical approaches, within a hierarchical structure, proceeding from higher levels of hierarchy (production situations and disease syndromes) to lower ones (individual components of production situations and individual diseases) were used. These analyses showed that (i) production situations, as wholes, represent very large risk factors (positive or negative) for occurrence of disease syndromes; (ii) production situations are strong risk factors for individual diseases; (iii) drivers of agricultural change represent strong risk factors of disease syndromes; and (iv) drivers of change, taken individually, represent small but significant risk factors for individual diseases. The latter analysis indicates that different diseases are positively or negatively associated with shifts in these drivers. We also report scenario analyses, in which drivers of agricultural change are varied in response to possible climate and global changes, generating predictions of shifts in rice health risks. The overall set of analyses emphasizes the need for large-scale ground data to define research priorities for plant protection in rapidly evolving contexts. They illustrate how a structured theoretical framework can be used to analyze emergent features of agronomic and socioecological systems. We suggest that the concept of “disease syndrome” can be borrowed in botanical epidemiology from public health to emphasize a holistic view of disease in shifting production situations in combination with the conventional, individual disease-centered perspective.
C-Terminal Region of Plant Ferredoxin-Like Protein Is Required to Enhance Resistance to Bacterial Disease in Arabidopsis thaliana
Authors: Lin Yi-Hsien , Huang Hsiang-En , Chen Yen-Ru , Liao Pei-Luan , Chen Ching-Lian , Feng Teng-Yung
Published: January 2011

Protein phosphorylation is an important biological process associated with elicitor-induced defense responses in plants. In a previous report, we described how plant ferredoxin-like protein (PFLP) in transgenic plants enhances resistance to bacterial pathogens associated with the hypersensitive response (HR). PFLP possesses a putative casein kinase II phosphorylation (CK2P) site at the C-terminal in which phosphorylation occurs rapidly during defense response. However, the contribution of this site to the enhancement of disease resistance and the intensity of HR has not been clearly demonstrated. In this study, we generated two versions of truncated PFLP, PEC (extant CK2P site) and PDC (deleted CK2P site), and assessed their ability to trigger HR through harpin (HrpZ) derived from Pseudomonas syringae as well as their resistance to Ralstonia solanacearum. In an infiltration assay of HrpZ, PEC intensified harpin-mediated HR; however, PDC negated this effect. Transgenic plants expressing these versions indicate that nonphosphorylated PFLP loses its ability to induce HR or enhance disease resistance against R. solanacearum. Interestingly, the CK2P site of PFLP is required to induce the expression of the NADPH oxidase gene, AtrbohD, which is a reactive oxygen species producing enzyme. This was further confirmed by evaluating the HR on NADPH oxidase in mutants of Arabidopsis. As a result, we have concluded that the CK2P site is required for the phosphorylation of PFLP to enhance disease resistance.