bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing the success of mine restoration using Hemiptera as indicators
Authors: Orabi Gamal , Moir Melinda L. , Majer Jonathan D.
Published: November 2010

Understanding trends in assemblage composition of key invertebrate groups can provide important insight into the ‘condition’ of, or changes in, the environment. Species density, abundance and composition of Hemiptera (true bugs) were assessed in jarrah (Eucalyptus marginata) forest and a chronosequence of restored bauxite mine pits near Boddington, Western Australia, in order to evaluate how restoration was progressing. A significant difference was uncovered for hemipteran species density between the youngest restored treatment and forest. In contrast, hemipteran composition was distinct between the forest and all restored treatments. Hemipteran composition was associated with the presence of the plant species Conostylis setigera and Trichocline spathulata, and plant structure between 160–180 cm and 260–280, plus soil pH. Restoration was successful in returning Hemiptera with respect to species density, but restoration was yet to attain a similar composition of Hemiptera to that of unmined forest, despite some of the restored sites being almost 20 years old. These results are similar to those of other studies that have assessed the response of Hemiptera to disturbance, and highlight the need to wait for considerable periods in order to achieve restoration goals. This study also confirms the utility of Hemiptera as bioindicators of environmental ‘condition’ and change.
Evolution of the mammalian embryonic pluripotency gene regulatory network
Authors: Fernandez-Tresguerres Beatriz , Cañon Susana , Rayon Teresa , Pernaute Barbara , Crespo Miguel , Torroja Carlos , Manzanares Miguel
Published: November 2010

Embryonic pluripotency in the mouse is established and maintained by a gene-regulatory network under the control of a core set of transcription factors that include octamer-binding protein 4 (Oct4; official name POU domain, class 5, transcription factor 1, Pou5f1), sex-determining region Y (SRY)-box containing gene 2 (Sox2), and homeobox protein Nanog. Although this network is largely conserved in eutherian mammals, very little information is available regarding its evolutionary conservation in other vertebrates. We have compared the embryonic pluripotency networks in mouse and chick by means of expression analysis in the pregastrulation chicken embryo, genomic comparisons, and functional assays of pluripotency-related regulatory elements in ES cells and blastocysts. We find that multiple components of the network are either novel to mammals or have acquired novel expression domains in early developmental stages of the mouse. We also find that the downstream action of the mouse core pluripotency factors is mediated largely by genomic sequence elements nonconserved with chick. In the case of
Sox2
and
Fgf4
, we find that elements driving expression in embryonic pluripotent cells have evolved by a small number of nucleotide changes that create novel binding sites for core factors. Our results show that the network in charge of embryonic pluripotency is an evolutionary novelty of mammals that is related to the comparatively extended period during which mammalian embryonic cells need to be maintained in an undetermined state before engaging in early differentiation events.
Songs of Darwin's finches diverge when a new species enters the community
Authors: Grant B. Rosemary , Grant Peter R.
Published: November 2010

Bird species sing different songs and as a result rarely breed with each other. Species are not static but can shift in acoustic and morphological space, yet maintain their distinctiveness. Investigating such a situation in a community of Darwin's finches sheds light on the origin and maintenance of premating barriers between species. Explanations for songs divergence generally invoke morphological changes to the sound-producing apparatus, environmental changes influencing transmitting properties of song, avoidance of acoustical interference with other species, and random processes including copying errors. We investigated changes in songs of
Geospiza fortis
(medium ground finch) and
Geospiza scandens
(cactus ground finch) from 1978 to 2010 on Daphne Major Island, Galápagos. The habitat did not change significantly; however, the finch community changed. The socially aggressive congener
Geospiza magnirostris
(large ground finch), singing in the same frequency band (2–4 kHz), colonized Daphne in 1983 and increased in numbers. Temporal features of the songs of
G. fortis
and
G. scandens
, especially trill rate and song duration, diverged from
G. magnirostris
songs as it became increasingly common. Changes in song were not a passive consequence of a change in beak morphology. Instead they arose as a bias during song imprinting and production. Sons of both
G. fortis
and
G. scandens
sang faster songs than their respective fathers and thereby differed more from
G. magnirostris
in their songs than did their fathers. Divergence from an aversive or confusing stimulus during learning illustrates a “peak shift” that may be a common feature of song evolution and speciation.
Effects of Postharvest Onion Curing Parameters on Enterobacter Bulb Decay in Storage
Authors: Schroeder B. K. , du Toit L. J.
Published: November 2010

Enterobacter bulb decay is a recently described storage disease of onion (Allium cepa) bulbs caused by Enterobacter cloacae. The disease is generally considered minor but, on occasion, can cause significant losses for onion producers. The impact of postharvest curing temperature and duration on Enterobacter bulb decay of onion was evaluated by inoculating bulbs of the cultivars Redwing and Vaquero with E. cloacae after harvest, curing the bulbs at 25, 30, 35, or 40°C for 2 or 14 days, and storing the bulbs at 5°C for 1, 2, or 3 months. Noninoculated bulbs and bulbs injected with sterile water served as control treatments. The trial was completed using bulbs harvested from commercial onion crops grown in the semi-arid Columbia Basin of central Washington in each of 2008–09 (center-pivot irrigated crop) and 2009–10 (drip irrigated crop). Severity of bulb rot was assessed by cutting each bulb down the center from the neck to the basal plate, and rating the percentage of cut surface area with bacterial rot symptoms. Bulb rot severity was negligible for noninoculated bulbs (mean of 0.3% in the 2008–09 storage trial and 1.0% in the 2009–10 storage trial) and bulbs injected with water (0.8% in the 2008–09 trial and 1.3% in the 2009–10 trial) compared to bulbs inoculated with E. cloacae (15.3% in 2008–09 and 23.3% in 2009–10). Severity of Enterobacter bulb decay was affected significantly (P < 0.05) by season (trial), cultivar, curing temperature, curing duration, and storage duration, with significant interactions among these factors. Enterobacter bulb decay was significantly more severe for bulbs cured at 40°C than for bulbs cured at 25, 30, or 35°C. This effect was even greater when bulbs were cured for 14 days versus 2 days prior to cold storage, and in bulbs stored for 2 or 3 months after curing compared to bulbs stored for 1 month. The increase in bulb rot severity caused by curing bulbs at 40°C for 14 days compared to lower temperatures and shorter durations was greater for Vaquero than Redwing, particularly in the 2008–09 trial. The results suggest that curing temperatures ≤35°C should significantly reduce the risk of Enterobacter bulb decay in storage for these cultivars. If higher curing temperatures are used in order to dry onion necks for long-term storage and reduce the risk of fungal diseases such as neck rot (caused by Botrytis spp.), a shorter curing duration may be necessary to minimize the risk of Enterobacter bulb decay in storage.
Discovery of skin alkaloids in a miniaturized eleutherodactylid frog from Cuba
Authors: Rodríguez Ariel , Poth Dennis , Schulz Stefan , Vences Miguel
Published: November 2010

Four phylogenetically independent lineages of frogs are currently known to sequester lipid-soluble skin alkaloids for which a dietary source has been demonstrated. We report here a remarkable fifth such instance, in
Eleutherodactylus iberia
and
Eleutherodactylus orientalis
, two species of miniaturized frogs of the family Eleutherodactylidae from Cuba. Six pumiliotoxins and two indolizidines were found in
E. iberia
, one of the smallest frogs in the world and characterized by a contrasting colour pattern for which we hypothesize an aposematic function. Analyses of stomach content indicated a numerical prevalence of mites with an important proportion of oribatids—a group of arthropods known to contain one of the pumiliotoxins detected in
E. iberia
. This suggests that miniaturization and specialization to small prey may have favoured the acquisition of dietary skin alkaloids in these amphibians.
The influence of physical activity level on heart rate variability among asthmatic adults
Authors: Tsai Yueh‐Shia , Lai Fu‐Chih , Chen Su‐Ru , Jeng Chii
Published: November 2010

Aims.  The aim of the study was to evaluate the impact of physical activity levels on heart rate variability among asthmatic patients.

Background.  In recent years, heart rate variability is frequently used to assess the autonomic nervous system. The pathogenesis of asthma is probably related to autonomic dysfunction. Adequate exercise is considered beneficial to patients who suffer from asthma. However, the relationship between physical activity and the autonomic nervous system of adult asthmatic patients is still unknown.

Design.  A cross‐sectional survey.

Methods.  A total of 54 subjects (27 healthy persons and 27 asthmatic patients matched by age and gender) were recruited for this study. Heart rate variability was determined by frequency analysis and measured in both resting and active states. The Seven‐Day Physical Activity Recall was used to determine the subject’s amount of weekly activity.

Results.  The results showed that the total power, low frequency (ms2), low frequency (nu) and low frequency/high frequency (nu) but not high frequency (nu) were significantly higher in healthy adults compared to asthmatic patients, no matter whether resting or exercising. In both groups, the greater the amount of moderate‐to‐vigorous physical activity, the higher the TP observed. However, a positive relationship between the amount of moderate‐to‐vigorous physical activity and low frequency (nu) and a negative relationship with high frequency (nu), respectively, was demonstrated only in asthmatic patients. There was no significant difference in heart rate variability between the asthmatic patients who engaged in more moderate‐to‐vigorous physical activity and the healthy patients.

Conclusions.  Although the asthmatic patients had poor heart rate variability compared with healthy people, engaging in higher amounts of moderate‐to‐vigorous physical activity may result in a heart rate variability similar to that of healthy people.

Relevance to clinical practice.  The results of this study suggest that healthcare professionals should encourage asthmatic patients to take as much physical exercise as they can in their daily lives.
Genetic analyses reveal hybridization but no hybrid swarm in one of the world’s rarest birds
Authors: STEEVES TAMMY E. , MALONEY RICHARD F. , HALE MARIE L. , TYLIANAKIS JASON M. , GEMMELL NEIL J.
Published: November 2010

Hybridization facilitated by human activities has dramatically altered the evolutionary trajectories of threatened taxa around the globe. Whereas introduced mammalian predators and widespread habitat loss and degradation clearly imperil the recovery and survival of the New Zealand endemic black stilt or kakī (Himantopus novaezelandiae), the risk associated with hybridization between this critically endangered endemic and its self‐introduced congener, the pied stilt or poaka (Himantopus himantopus leucocephalus) is less clear. Here, we combine Bayesian admixture analyses of microsatellite data with mitochondrial DNA sequence data to assess the levels of hybridization and introgression between kakī and poaka. We show that birds classified as hybrids on the basis of adult plumage are indeed of hybrid origin and that hybridization between kakī and poaka is both extensive and bidirectional. Despite this, we found almost no evidence for introgression from poaka to kakī, thus negating the popular belief that kakī represent a hybrid swarm. To our knowledge, ours represents the first comprehensive study to document a lack of widespread introgression for a species at risk despite a recent history of extensive bidirectional human‐induced hybridization. We attribute this rather surprising result, in part, to reduced reproductive success in female hybrids combined with a transient male‐biased kakī sex ratio. To maximize the evolutionary potential of kakī, we use these data to recommend conservation management activities aimed to maintain the genetic integrity and to maximize the genetic diversity of this iconic rare bird.
Phylogenetics of Acrocirridae and Flabelligeridae (Cirratuliformia, Annelida)
Authors: Osborn Karen J. , Rouse Greg W.
Published: November 2010

Osborn, K. J. & Rouse, G. W. (2010). Phylogenetics of Acrocirridae and Flabelligeridae (Cirratuliformia, Annelida). —Zoologica Scripta, 40, 204–219.

When seven deep‐sea, swimming cirratuliforms were recently discovered, the need for a thorough phylogenetic hypothesis for Cirratuliformia was clear. Here, we provide a robust phylogenetic hypothesis for the relationships within Acrocirridae and increase the taxon sampling and resolution within Flabelligeridae based on both molecular (18S, 28S, 16S, COI and CytB) and morphological data. Data partitions were analyzed separately and in combination. Acrocirridae and Flabelligeridae were reciprocally monophyletic sister groups when rooted by cirratulids. The seven recently discovered species form a clade within Acrocirridae and will be designated as four genera based on phylogenetic relationships and apomorphies. A revised diagnosis is provided for Swima, restricting the genus to three species distinguished by a thick gelatinous sheath, transparent body, simple nuchal organs, a single medial subulate branchia, and four pair of small segmental branchiae modified as elliptical, bioluminescent sacs. Helmetophorus and Chauvinelia are maintained as separate genera based on morphological differences. Evidence for flabelligerid branchiae being segmental is provided, the papillae on segment two of most acrocirrids is confirmed to be the nephridiopores, and scanning electron microscopy is used to examine acrocirrid spinous chaetae in comparison with flabelligerid segmented chaetae.
China's Emerging Global Role: Dissatisfied Responsible Great Power
Authors: Breslin Shaun
Published: November 2010

China has (re-)emerged as a great power in a world not of its own making. The distribution of power in major organisations and the dominant norms of international interactions are deemed to favour unfairly the existing Western powers, and at times obstruct China's ability to meet national development goals. Nevertheless, engaging the global economy has been a key source of economic growth (thus helping to maintain regime stability), and establishing China's credentials as a responsible global actor is seen as a means of ensuring continued access to what China needs. As an emerging great power which is also still in many respects a developing country, China's challenge is to change the global order in ways that do not cause global instability or generate crises that would damage China's own ability to generate economic growth and ensure political stability.
Inclusion in school: a policy, ideology or lived experience? Similar findings in diverse school cultures
Authors: PALIOKOSTA PATY , BLANDFORD SONIA
Published: November 2010

This article summarises three case studies examining the implementation of inclusive practices, which evidence the exclusionary pressures acting in school settings that put the needs, rights and entitlements of vulnerable children and young people at risk. It examines how three very culturally different secondary schools in England interpreted inclusive policies and illuminates the various constraints to the implementation of inclusive practices as experienced by senior leaders, teachers, parents and pupils in these schools. Conceptual unpreparedness towards inclusion versus integration, knowledge and false conceptualisations of special educational needs and difficulties associated with differentiation and time limitations were the main barriers presented. The implications for initial and professional teacher education are posited; it is suggested that inclusion can work by removing the diagnostic paradigm associated with special educational needs and by creating a framework for teachers' lifelong learning focusing on a social justice oriented pedagogy that will empower teachers conceptually and practically.
Correlation of Overexpression of Efflux Pump Genes with Antibiotic Resistance inEscherichia coliStrains Clinically Isolated from Urinary Tract Infection Patients
Authors: Yasufuku Tomihiko , Shigemura Katsumi , Shirakawa Toshiro , Matsumoto Minori , Nakano Yuzo , Tanaka Kazushi , Arakawa Soichi , Kinoshita Shouhiro , Kawabata Masato , Fujisawa Masato
Published: November 2010

Escherichia coliis one of the most common pathogens in urinary tract infections (UTIs), and antibiotic resistance inE. coliis becoming a serious problem in treating UTI. Efflux system overexpression is reported to contribute toE. coliresistance to several antibiotics. This study investigated the correlation of antibiotic susceptibilities with the overexpression of the efflux pump genes such asmarA,yhiU,yhiV, andmdfAand with risk factors for antibiotic resistance inE. coliisolated from UTI patients. We examined the expression level of efflux pump genes using quantitative real-time reverse transcription-PCR (qRT-PCR). We also tested thein vitrosusceptibilities to 12 kinds of antibiotics in 64 clinical strains ofE. coliisolated from UTI patients. By multivariate analyses we revealed significant relationships between the overexpression of (i)marAand MICs of cefepime (FEP) and nalidixic acid (NAL), (ii)yhiVand MICs of minocycline (MIN), and (iii)mdfAand MICs of sitafloxacin (STX). In our investigation of the efflux pump genes, risk factors such as gender and the previous use of fluoroquinolones correlated with the overexpression ofmarA, and indwelling catheter use correlated with the overexpression ofmdfA. In conclusion, we demonstrated that the increased expression of efflux pump genes such asmarAandmdfAcan lead to fluoroquinolone resistance inE. coli. These results contribute to our knowledge of the efflux system and raise the possibility of developing new agents, such as efflux pump inhibitors (EPIs), to antibiotic-resistantE. coli.
Comparison of Detection Methods for Heteroresistant Vancomycin-Intermediate
Staphylococcus aureus
, with the Population Analysis Profile Method as the Reference Method
Authors: Satola Sarah W. , Farley Monica M. , Anderson Karen F. , Patel Jean B.
Published: November 2010

Staphylococcus aureus
clinical isolates with vancomycin MICs of 2 μg/ml have been associated with vancomycin therapeutic failure and the heteroresistant vancomycin-intermediate
S. aureus
(hVISA) phenotype. A population analysis profile (PAP) with an area under the curve (AUC) ratio of ≥0.9 for the AUC of the clinical isolate versus the AUC for hVISA strain Mu3 is most often used for determining hVISA, but it is time-consuming and labor-intensive. A collection of 140 MRSA blood isolates with vancomycin MICs of 2 μg/ml by reference broth microdilution and screened for hVISA using PAP-AUC (21/140 [15%] hVISA) were tested by additional methods to detect hVISA. The methods included (i) Etest macromethod using vancomycin and teicoplanin test strips, brain heart infusion (BHI) agar, and a 2.0 McFarland inoculum; (ii) Etest glycopeptide resistance detection (GRD) using vancomycin-teicoplanin double-sided gradient test strips on Mueller-Hinton agar (MHA) with 5% sheep blood and a 0.5 McFarland inoculum; and (iii) BHI screen agar plates containing 4 μg/ml vancomycin and 16 g/liter casein using 0.5 and 2.0 McFarland inocula. Each method was evaluated using PAP-AUC as the reference method. The sensitivity of each method for detecting hVISA was higher when the results were read at 48 h. The Etest macromethod was 57% sensitive and 96% specific, Etest GRD was 57% sensitive and 97% specific, and BHI screen agar was 90% sensitive and 95% specific with a 0.5 McFarland inoculum and 100% sensitive and 68% specific with a 2.0 McFarland inoculum. BHI screen agar with 4 μg/ml vancomycin and casein and a 0.5 McFarland inoculum had the best sensitivity and specificity combination, was easy to perform, and may be useful for clinical detection of hVISA.
LysGH15, a Novel Bacteriophage Lysin, Protects a Murine Bacteremia Model Efficiently against Lethal Methicillin-Resistant
Staphylococcus aureus
Infection
Authors: Gu Jingmin , Xu Wei , Lei Liancheng , Huang Jing , Feng Xin , Sun Changjiang , Du Chongtao , Zuo Jing , Li Yang , Du Taofeng , Li Linxi , Han Wenyu
Published: November 2010

Phage-coded lysin is an enzyme that destroys the cell walls of bacteria. Phage lysin could be an alternative to conventional antibiotic therapy against pathogens that are resistant to multiple antibiotics. In this study, a novel staphylococcal phage, GH15, was isolated, and the endogenous lytic enzyme (LysGH15) was expressed and purified. The lysin LysGH15 displayed a broad lytic spectrum;
in vitro
treatment killed a number of
Staphylococcus aureus
strains rapidly and completely, including methicillin-resistant
S. aureus
(MRSA). In animal experiments, a single intraperitoneal injection of LysGH15 (50 μg) administered 1 h after MRSA injections at double the minimum lethal dose was sufficient to protect mice (
P
< 0.01). Bacteremia in unprotected mice reached colony counts of about 10
7
CFU/ml within 3.5 h after challenge, whereas the mean colony count in lysin-protected mice was less than 10
4
CFU/ml (and ultimately became undetectable). These results indicate that LysGH15 can kill
S. aureus in vitro
and can protect mice efficiently from bacteremia
in vivo
. The phage lysin LysGH15 might be an alternative treatment strategy for infections caused by MRSA.
Bocavirus Infection Induces a DNA Damage Response That Facilitates Viral DNA Replication and Mediates Cell Death
Authors: Luo Yong , Chen Aaron Yun , Qiu Jianming
Published: November 2010

Minute virus of canines (MVC) is an autonomous parvovirus that replicates efficiently without helper viruses in Walter Reed/3873D (WRD) canine cells. We previously showed that MVC infection induces mitochondrion-mediated apoptosis and G2/M-phase arrest in infected WRD cells. However, the mechanism responsible for these effects has not been established. Here, we report that MVC infection triggers a DNA damage response in infected cells, as evident from phosphorylation of H2AX and RPA32. We discovered that both ATM (ataxia telangiectasia-mutated kinase) and ATR (ATM- and Rad3-related kinase) were phosphorylated in MVC-infected WRD cells and confirmed that ATM activation was responsible for the phosphorylation of H2AX, whereas ATR activation was required for the phosphorylation of RPA32. Both pharmacological inhibition of ATM activation and knockdown of ATM in MVC-infected cells led to a significant reduction in cell death, a moderate correction of cell cycle arrest, and most importantly, a reduction in MVC DNA replication and progeny virus production. Parallel experiments with an ATR-targeted small interfering RNA (siRNA) had no effect. Moreover, we identified that this ATM-mediated cell death is p53 dependent. In addition, we localized the Mre11-Rad50-Nbs1 (MRN) complex, the major mediator as well as a substrate of the ATM-mediated DNA damage response pathway to MVC replication centers during infection, and show that Mre11 knockdown led to a reduction in MVC DNA replication. Our findings are the first to support the notion that an autonomous parvovirus is able to hijack the host DNA damage machinery for its own replication and for the induction of cell death.
Stepwise Loss of Fluorescent Core Protein V from Human Adenovirus during Entry into Cells
Authors: Puntener Daniel , Engelke Martin F. , Ruzsics Zsolt , Strunze Sten , Wilhelm Corinne , Greber Urs F.
Published: November 2010

Human adenoviruses (Ads) replicate and assemble particles in the nucleus. They organize a linear double-strand DNA genome into a condensed core with about 180 nucleosomes, by the viral proteins VII (pVII), pX, and pV attaching the DNA to the capsid. Using reverse genetics, we generated a novel, nonconditionally replicating Ad reporter by inserting green fluorescent protein (GFP) at the amino terminus of pV. Purified Ad2-GFP-pV virions had an oversized complete genome and incorporated about 38 GFP-pV molecules per virion, which is about 25% of the pV levels in Ad2. GFP-pV cofractionated with the DNA core, like pV, and newly synthesized GFP-pV had a subcellular localization indistinguishable from that of pV, indicating that GFP-pV is a valid reporter for pV. Ad2-GFP-pV completed the replication cycle, although at lower yields than Ad2. Incoming GFP-pV (or pV) was not imported into the nucleus. Virions lost GFP-pV at two points during the infection process: at entry into the cytosol and at the nuclear pore complex, where capsids disassemble. Disassembled capsids, positive for the conformation-specific antihexon antibody R70, were devoid of GFP-pV. The loss of GFP-pV was reduced by the macrolide antibiotic leptomycin B (LMB), which blocks nuclear export and adenovirus attachment to the nuclear pore complex. LMB inhibited the appearance of R70 epitopes on Ad2 and Ad2-GFP-pV, indicating that the loss of GFP-pV from Ad2-GFP-pV is an authentic step in the adenovirus uncoating program. Ad2-GFP-pV is genetically complete and hence enables detailed analyses of infection and spreading dynamics in cells and model organisms or assessment of oncolytic adenoviral potential.
Human Cytomegalovirus Early Protein pUL21a Promotes Efficient Viral DNA Synthesis and the Late Accumulation of Immediate-Early Transcripts
Authors: Fehr Anthony R. , Yu Dong
Published: November 2010

We have previously reported that a newly annotated gene of human cytomegalovirus (HCMV), UL21a, encodes an early viral protein termed pUL21a. Most notably, the virions of a UL21a deletion virus had markedly reduced infectivity, indicating that UL21a is required to establish an efficient productive infection. In this study, we infected fibroblasts with equal numbers of DNA-containing viral particles and identified where in the viral life cycle pUL21a acted. The UL21a deletion virus entered cells and initiated viral gene expression efficiently; however, it synthesized viral DNA poorly and accumulated several immediate-early (IE) transcripts at reduced levels at late times of infection. The defect in viral DNA synthesis preceded that in gene expression, and inhibition of viral DNA synthesis reduced the late accumulation of IE transcripts in both wild-type and mutant virus-infected cells to equivalent levels. This suggests that reduced viral DNA synthesis is the cause of reduced IE gene expression in the absence of UL21a. The growth of UL21a deletion virus was similar to that of recombinant HCMV in which pUL21a expression was abrogated by stop codon mutations, and the defect was rescued in pUL21a-expressing fibroblasts. pUL21a expression in
trans
was sufficient to restore viral DNA synthesis and gene expression of mutant virus produced from normal fibroblasts, whereas mutant virus produced from complementing cells still exhibited the defect in normal fibroblasts. Thus, pUL21a does not promote the functionality of HCMV virions; rather, its
de novo
synthesis facilitates viral DNA synthesis, which is necessary for the late accumulation of IE transcripts and establishment of a productive infection.
The Acidic Domain of Hepatitis C Virus NS4A Contributes to RNA Replication and Virus Particle Assembly
Authors: Phan Tung , Kohlway Andrew , Dimberu Peniel , Pyle Anna Marie , Lindenbach Brett D.
Published: November 2010

Hepatitis C virus NS3-4A is a membrane-bound enzyme complex that exhibits serine protease, RNA helicase, and RNA-stimulated ATPase activities. This enzyme complex is essential for viral genome replication and has been recently implicated in virus particle assembly. To help clarify the role of NS4A in these processes, we conducted alanine scanning mutagenesis on the C-terminal acidic domain of NS4A in the context of a chimeric genotype 2a reporter virus. Of 13 mutants tested, two (Y45A and F48A) had severe defects in replication, while seven (K41A, L44A, D49A, E50A, M51A, E52A, and E53A) efficiently replicated but had severe defects in virus particle assembly. Multiple strategies were used to identify second-site mutations that suppressed these NS4A defects. The replication defect of NS4A F48A was partially suppressed by mutation of NS4B I7F, indicating that a genetic interaction between NS4A and NS4B contributes to RNA replication. Furthermore, the virus assembly defect of NS4A K41A was suppressed by NS3 Q221L, a mutation previously implicated in overcoming other virus assembly defects. We therefore examined the known enzymatic activities of wild-type or mutant forms of NS3-4A but did not detect specific defects in the mutants. Taken together, our data reveal interactions between NS4A and NS4B that control genome replication and between NS3 and NS4A that control virus assembly.
Pilot study: a randomised, double blind, placebo controlled trial of pancrealipase for the treatment of postprandial irritable bowel syndrome-diarrhoea
Authors: Money Mary E , Walkowiak Jaroslaw , Virgilio Chris , Talley Nicholas J
Published: November 2010

Objective

To evaluate the efficacy of pancrealipase (PEZ) compared with placebo in the reduction of postprandial irritable bowel syndrome-diarrhoea (IBS-D).

Design

An intention to treat, double blind, randomised, crossover trial comparing PEZ to placebo for reduction of postprandial IBS-D. Patients had to recognise at least two different triggering foods, be willing to consume six baseline ‘trigger meals’ and again blinded with PEZ and placebo. Patients then chose which drug they preferred for another 25 meals.

Setting

Outpatient internal medicine practice clinic.

Patients

255 patients were screened; 83 met the criteria, including 5 years of symptoms, recognised ‘food triggers’, no other identifiable cause for the symptoms, either a normal colonoscopy or barium enema while symptomatic and able to discontinue all anticholinergic medications. 69 patients were enrolled, 20 withdrew before randomisation, leaving 49 patients: 14 men, 35 women, mean age 52 years (SD 15.3). Over 60% had experienced symptoms for 11–30 years and 16% for more than 40 years.

Interventions

After completing six baseline meals, patients were randomised in blocks of four to receive either identical PEZ or a placebo for another six meals, and after a washout period of time received the alternative drug.

Main outcome measures

The primary analysis was number of patients who chose PEZ over placebo for the extended use.

Results

Overall, 30/49 (61%) would have chosen PEZ (p=0.078), with first drug preference for PEZ at 0.002. Among the PEZ subgroup, PEZ use compared with placebo, demonstrated improvement in all symptoms (p≤0.001) for cramping, bloating, borborygami, urge to defecate, global pain and decrease stooling with increase in stool firmness.

Conclusions

PEZ was found in a small group of patients to reduce postprandial IBS-D symptoms and deserves further evaluation.
Proteins responding to drought and high-temperature stress in Pinus armandii Franch
Authors: He Cai-Yun , Zhang Jian-Guo , Duan Ai-Guo , Sun Hong-Gang , Fu Li-Hua , Zheng Shu-Xing
Published: November 2010

Proteomic analysis provides a powerful method for studying plant responses to stress at the protein level. To study stress-responsive molecular mechanisms for Pinus armandii Franch, one of the most important forest plantation tree species in subalpine regions of Asia, we analyzed the response of 2-year-old P. armandii seedlings to drought and high temperature using two-dimensional gel electrophoresis. More than 550 reproducible needle proteins were detected in the controls and treatments, and the abundance of 27 proteins were found to change noticeably. We identified five proteins affected by drought stress and eight proteins affected by high temperature. These proteins are functionally quite diverse and are involved in photosynthesis, cell division and elongation, antioxidant metabolism, ammonia assimilation, growth and development, and protein folding. Our results provide fundamental data for future research on responses to drought and high temperature. As drought and high temperature are two major factors limiting the growth of subalpine forests during summer under recent global warming, this research may contribute to an understanding of the development of stress tolerance in trees.
Female gametophyte and seed development inMusella lasiocarpa(Musaceae), a monotypic genus endemic to Southwestern China
Authors: Xue Chun-Ying , Wang Hong , Li De-Zhu
Published: November 2010

Musella is a monotypic genus composed of a single species, Musella lasiocarpa (Franch.) C.Y. Wu ex H.W. Li, endemic to Southwestern China. The genus status of Musella remains controversial. Musella had been placed first in Musa , then in Ensete , and back to Musa before its monotypic status was recognized. Musella was reported to be extinct in the wild and maintained through cultivation only via vegetative propagation through sprouting of rhizomes. In this study, female gametophyte and seed development of Musella are described to assess its systematic position and possible reasons why the wild population is now extinct. The ovules are anatropous, bitegmic, and crassinucellar. The micropyle is formed by both integuments. The megaspore mother cell undergoes meiotic division and forms a linear megaspore triad or more rarely, a T-shaped megaspore tetrad. The chalazal megaspore develops into a Polygonum type embryo sac. A nucellar pad forms, and a hypostase differentiates. Fertilization is porogamous. Endosperm formation is of the nuclear type. The zygote degenerates and so the process by which the embryo develops, if it does, remains unclear. An operculum, micropylar collar, and chalazal chamber form in mature seeds. The storage tissue is mainly endosperm containing large, compound starch grains and some perisperm. The seed coat has lignified exotestal cells, 25–30 cell layers of sclerotic mesotestal cells, and unspecialized endotesta cells; the tegment consists of two layers of longitudinally elongated cells. The seed is inviable. After comparison with the other Musaceae s. str. taxa using embryological and botanical features, we conclude that Musella should be a distinct genus. Female sterility in Musella may be the main reason why the wild population is extinct. Based on these findings, we propose conservation strategies for this endemic species, including habitat protection as well as ex-situ conservation.
Effects of nutrients and water levels on species composition in prairie whitetop (Scolochloa festucacea) marshes
Authors: Neill Christopher
Published: November 2010

Nitrogen and phosphorus fertilizers were added over two growing seasons to whitetop marshes growing at the shallow and deep extremes of whitetop's water depth range in a northern prairie marsh to assess the effects of nutrient additions and water levels on species composition and understory species biomass. Nitrogen and nitrogen plus phosphorus additions reduced understory species biomass and caused only small changes in marsh species composition after 1 year, but dramatically decreased whitetop biomass and increased the biomass of the understory moist soil annual Atriplex patula at both water depths after 2 years. Phosphorus alone had little effect on species composition. Water levels influenced both the biomass of understory species and their potential response to nutrient additions. Biomass of understory species during both years was lower in deeper water. Nutrients had no effect on understory species biomass when standing water was present because standing water prevented seed germination. A mulching effect caused by greater whitetop litter accumulation and weaker whitetop stems associated with nitrogen fertilization appeared to be more important influences on understory species composition than differential understory species growth responses to added nutrients. Predicting responses of whitetop marshes to multiyear fertilization requires an understanding of the interactions between the physical conditions caused by increased biomass of whitetop, the relative abilities of understory moist soil species to grow under those conditions, and water levels, which control understory species seed germination and plant survival.
Piromyces mae and Piromyces dumbonica, two new species of uniflagellate anaerobic chytridiomycete fungi from the hindgut of the horse and elephant
Authors: Li Jinliang , Heath I. Brent , Bauchop Tom
Published: November 2010

Vegetative thalli, developing sporangia, and zoospores of two new uniflagellate anaerobic chytridiomycete gut fungi, Piromyces mae sp. nov. and Piromyces dumbonica sp.nov., isolated from manure derived from the hindgut of the horse and elephant, respectively, were examined by light and electron microscopy. Piromyces mae differs from Piromyces communis by having papillae-like structures on the sporangium. Piromyces dumbonica differs from P. communis by its C-shaped elongated circumflagellar ring and characteristic organelle distribution in the zoospores. The circumflagellar rings in both new species are tilted at about 10° towards the spur in both prereleased and free zoospores. Three struts in both species connect the circumflagellar ring to the skirt and connective (a newly described perikinetosomal structure) surrounding the kinetosome opposite to the skirt. The connective interconnects the strut, skirt, scoop, kinetosome, and spur. A general model of the kinetosome and perikinetosomal apparatus is proposed for the gut fungi. This model attempts to unify and clarify previous descriptions of the apparatus in these fungi and shows the limited range of variations reported. Key words: gut fungi, Chytridiomycetes, kinetosomes, perikinetosomal apparatus.
The influence of the detergent Triton X-100 on the growth and ultrastructure of tobacco pollen tubes
Authors: Rao K. S. , Kristen U.
Published: November 2010

The influence of the detergent Triton X-100 on the growth and ultrastructure of tobacco pollen tubes was studied using a culture technique. Tube growth inhibition increased with increasing concentration of the detergent in the culture medium. At a concentration of 7.5 mg∙l−1 (effective dose) the detergent induced a 50% reduction of pollen tube growth. The effective dose is defined as the concentration of a toxic substance that causes a decrease of a metabolic process to 50% of the control. Growth inhibition was reflected by changes of tube ultrastructure and shape at the tip region. The ultrastructural alterations in the pollen tube following the cytotoxic effect of the detergent included (i) disturbance of the cytoplasmic zonation in the tip region of the tube, (ii) numerical decrease of stacked dictyosomes (reduction of Golgi activity), (iii) damage of the plasma membrane and deposition of vesicular structures in the periplasmic space, (iv) formation of concentric arrangements of rough ER, (v) damage of the mitochondrial matrix and cristae and (vi) tube wall thickening-and loosening. The Thiéry reaction revealed the polysaccharide nature of the vesicle contents and the glycolipid nature of the lipid bodies. Scanning electron microscopy demonstrated curvature and tip swelling of the detergent-treated pollen tubes. Most of these changes were likely due to the action of the detergent on membranes. Key words: Nicotiana sylvestris, pollen tubes, detergent, growth inhibition, ultrastructure, biomembranes.
Magnetic excitations of spin and orbital moments in cobalt oxideSpecial issue on Neutron Scattering in Canada.
Authors: Yamani Z. , Buyers W. J.L. , Cowley R. A. , Prabhakaran D.
Published: November 2010

Magnetic and phonon excitations in the antiferromagnet CoO with an unquenched orbital angular momentum are studied by neutron scattering. Results of energy scans in several Brillouin zones in the (HHL) plane for energy transfers up to 16 THz are presented. The measurements were performed in the antiferromagnetic ordered state at 6 K (well below TN ∼290 K) as well as in the paramagnetic state at 450 K. Several magnetic excitation modes are identified from the dependence of their intensity on wavevector and temperature. Within a Hund’s rule model, the excitations correspond to fluctuations of coupled orbital and spin degrees of freedom, whose bandwidth is controlled by interionic superexchange. The different <111> ordering domains give rise to several magnetic peaks at each wavevector transfer.
Cold-neutron depth profiling as a research tool for the study of surface oxides on metalsSpecial Issue on Neutron Scattering in Canada.
Authors: Tun Z. , Noël J. J. , Bohdanowicz Th. , Cao L. R. , Downing R. G. , Goncharova L. V.
Published: November 2010

A recent experiment at NIST has demonstrated that neutron depth profiling (NDP) based on the (n, α) reaction could be developed into a tool that could be routinely used for the study of passive oxides on metals. Whereas most metals are not (n, α) active, oxides grown with 17O, the only (n, α) active oxygen isotope, can be observed and tracked by this technique. Problems due to contamination of the samples by boron were encountered, but were shown to be surmountable. For our samples, the NDP facility at NIST, as it exists today, has enough flux and energy resolution to separate the α particles emitted by 17O from those emitted by 10B. Substantial improvement in the data collection rate, easily achievable with arrays of additional detectors, will make NDP a useful tool in the study of passive oxides.
Modulation of Na+-K+-ATPase cell surface abundance through structural determinants on the α1-subunit
Authors: Pierre Sandrine V. , Belliard Aude , Sottejeau Yoann
Published: November 2010

Through their ion-pumping and non-ion-pumping functions, Na+-K+-ATPase protein complexes at the plasma membrane are critical to intracellular homeostasis and to the physiological and pharmacological actions of cardiotonic steroids. Alteration of the abundance of Na+-K+-ATPase units at the cell surface is one of the mechanisms for Na+-K+-ATPase regulation in health and diseases that has been closely examined over the past few decades. We here summarize these findings, with emphasis on studies that explicitly tested the involvement of defined regions or residues on the Na+-K+-ATPase α1 polypeptide. We also report new findings on the effect of manipulating Na+-K+-ATPase membrane abundance by targeting one of these defined regions: a dileucine motif of the form [D/E]XXXL[L/I]. In this study, opossum kidney cells stably expressing rat α1 Na+-K+-ATPase or a mutant where the motif was disrupted (α1-L499V) were exposed to 30 min of substrate/coverslip-induced-ischemia followed by reperfusion (I-R). Biotinylation studies suggested that I-R itself acted as an inducer of Na+-K+-ATPase internalization and that surface expression of the mutant was higher than the native Na+-K+-ATPase before and after ischemia. Annexin V/propidium iodide staining and lactate dehydrogenase release suggested that I-R injury was reduced in α1-L499V-expressing cells compared with α1-expressing cells. Hence, modulation of Na+-K+-ATPase cell surface abundance through structural determinants on the α-subunit is an important mechanism of regulation of cellular Na+-K+-ATPase in various physiological and pathophysiological conditions, with a significant impact on cell survival in face of an ischemic stress.
Renal tubular angiogenic dysregulation in anti-Thy1.1 glomerulonephritis
Authors: Cina Davide P. , Xu Hui , Liu Limin , Farkas Laszlo , Farkas Daniela , Kolb Martin , Margetts Peter J.
Published: November 2010

Peritubular vascular changes and hypoxia after glomerular injury may explain subsequent tubulointerstitial injury and fibrosis. Several studies suggested that the expected tubulointerstitial angiogenic response is actively suppressed in this setting. The mechanism of this aberrant response has not been clearly identified. We used a common model of glomerular injury in rats to assess vascular changes and to identify potential factors associated with this aberrant response. Anti-Thy1.1 antibody administration (1 or 4 weekly doses) led to a dose-dependent renal damage characterized by elevated urea and tubulointerstitial fibrosis as assessed by Picro-Sirius Red staining. We quantified peritubular capillaries using CD31 and CD34 immunohistochemistry and showed that tubular angiogenic dysregulation was associated with peritubular capillary rarefaction. Using laser capture microdissection, we demonstrated an early induction of fibrogenic and angiogenic factors in the glomeruli and a subsequent dysregulated angiogenic response in the tubulointerstitial compartment. Proximal tubules of anti-Thy1.1-treated animals had increased pigment epithelial-derived factor (PEDF) expression by immunohistochemistry. Protein taken by laser capture microdissection also showed that PEDF was upregulated. Temporally associated with PEDF expression was a transient downregulation of tubular hypoxia-inducible factor (HIF)1α. In a human proximal tubular cell culture, we show that PEDF downregulates HIF1α protein and gene expression in cells exposed to 1% oxygen. In anti-Thy1.1 glomerulonephritis, there is aberrent tubular angiogenesis associated with glomerular injury and tubulointersititial fibrosis. We showed that PEDF may be involved by downregulating HIF1α. Further work is needed to elucidate the mechanism of PEDF upregulation and action in the tubules.
Neurotrophin/receptor expression in urinary bladder of mice with overexpression of NGF in urothelium
Authors: Girard Beatrice M. , Malley Susan E. , Vizzard Margaret A.
Published: November 2010

Urothelium-specific overexpression of nerve growth factor (NGF) in the urinary bladder of transgenic mice stimulates neuronal sprouting in the urinary bladder, produces increased voiding frequency, and results in increased referred somatic hypersensitivity. Additional NGF-mediated pleiotropic changes might contribute to the increased voiding frequency and pelvic hypersensitivity observed in these transgenic mice, such as modulation of other growth factor/receptor systems. Chronic overexpression of NGF in the urothelium was achieved through the use of a highly urothelium-specific uroplakin II promoter. In the present study, we examined NGF, brain-derived neurotrophic factor (BDNF), and associated receptor [p75NTR, tyrosine kinase (Trk)A, TrkB] transcript and protein expression in urothelium and detrusor smooth muscle of NGF-overexpressing (OE) and littermate wild-type mice, using real-time quantitative reverse transcription-polymerase chain reaction, ELISAs, and semiquantitation of immunohistochemistry. We focused on these growth factor/receptors given the established roles of NGF/TrkA, NGF/p75NTR, and BDNF/TrkB systems in bladder function. Increased voiding frequency in NGF-OE mice was confirmed by examining urination patterns. BDNF, TrkA, and TrkB protein expression was significantly ( P ≤ 0.01) reduced and p75NTRprotein expression was significantly ( P ≤ 0.01) increased in urinary bladder of NGF-OE mice. The NGF-OE-induced changes in neurotrophic factor/receptor expression in urinary bladder may represent compensatory changes to reduce voiding frequency in the NGF-OE mouse.