bluuebunny/crossref_metadata_2025_split huggingface dataset:
CcpA‐mediated repression of Clostridium difficile toxin gene expression
Authors: Antunes Ana , Martin‐Verstraete Isabelle , Dupuy Bruno 
Published: December 2010

SummaryThe presence of glucose or other rapidly metabolizable carbon sources in the bacterial growth medium strongly represses Clostridium difficile toxin synthesis independently of strain origin. In Gram‐positive bacteria, carbon catabolite repression (CCR) is generally regarded as a regulatory mechanism that responds to carbohydrate availability. In the C. difficile genome all elements involved in CCR are present. To elucidate in vivo the role of CCR in C. difficile toxin synthesis, we used the ClosTron gene knockout system to construct mutants of strain JIR8094 that were unable to produce the major components of the CCR signal transduction pathway: the phosphotransferase system (PTS) proteins (Enzyme I and HPr), the HPr kinase/phosphorylase (HprK/P) and the catabolite control protein A, CcpA. Inactivation of the ptsI, ptsH and ccpA genes resulted in derepression of toxin gene expression in the presence of glucose, whereas repression of toxin production was still observed in the hprK mutant, indicating that uptake of glucose is required for repression but that phosphorylation of HPr by HprK is not. C. difficile CcpA was found to bind to the regulatory regions of the tcdA and tcdB genes but not through a consensus cre site motif. Moreover in vivo and in vitro results confirmed that HPr‐Ser45‐P does not stimulate CcpA‐dependent binding to DNA targets. However, fructose‐1,6‐biphosphate (FBP) alone did increase CcpA binding affinity in the absence of HPr‐Ser45‐P. These results showed that CcpA represses toxin expression in response to PTS sugar availability, thus linking carbon source utilization to virulence gene expression in C. difficile.
A novel role for a glycosylphosphatidylinositol‐anchored aspartyl protease, CgYps1, in the regulation of pH homeostasis in Candida glabrata
Authors: Bairwa Gaurav , Kaur Rupinder 
Published: December 2010

SummaryProteases, key virulence factors of many bacterial and fungal pathogens, are pivotally important for nutrient acquisition, invasion and adherence to host cells and evasion/escape from host immune cells. In this study, we report a novel role for CgYps1, member of a family of 11 GPI‐linked aspartyl proteases, in a human opportunistic fungal pathogen, Candida glabrata, in the regulation of pH homeostasis under acidic environmental conditions. We show that CgYps1 is required to survive low‐external‐pH environment and the inability of Cgyps1Δ mutant to maintain pH homeostasis results in intracellular acidification and increased reactive oxygen species (ROS) production. We also provide evidence that the reduced intracellular pH in Cgyps1Δ mutant under acidic conditions is, partly, owing to the diminished activity of a plasma membrane proton pump, CgPma1, an orthologue of a key component of pH homeostasis machinery in Saccharomyces cerevisiae, Pma1. In addition, we have examined C. glabrata's response to low environmental pH via genome‐wide expression analysis and several genes required for protein folding/modification and stress response pathways including seven of the CgYPS genes were found to be upregulated. Lastly, we show that C. glabrata responds to acidic environment by reducing total β‐glucan levels in the cell wall in a CgYps1‐dependent manner.
Effect of Pre‐freeze Addition of Cysteine Hydrochloride and Reduced Glutathione in Semen of Crossbred Jersey Bulls on Sperm Parameters and Conception Rates
Authors: Perumal P , Selvaraju S , Selvakumar S , Barik AK , Mohanty DN , Das S , Das RK , Mishra PC 
Published: December 2010

ContentsThis study was aimed to assess the effect of pre‐freeze addition of cysteine hydrochloride and glutathione (GSH) on post‐thaw sperm functional parameters and field fertility. The experimental bulls (n = 6) aged 4–6 years were used for this study. A total of 36 ejaculates (six ejaculates per bull) were collected and divided into three groups, group I (control), group II (5 mmcysteine hydrochloride) and group III (5 mmGSH). The extended semen samples with and without additives were filled in mini straw using automatic filling and sealing machine and cryopreserved in liquid nitrogen. Post‐freeze seminal traits were recorded after thawing at 37°C for 30 s. The curvilinear velocity (VCL) and amplitude of lateral head displacement values were significantly (p < 0.05) higher in GSH than the cysteine and control groups. Post‐thaw plasmalemma integrity was significantly (p < 0.01) higher in GSH group when compared to cysteine and control groups. The loss of acrosomal integrity was significantly (p < 0.01) lower in GSH than in cysteine and control groups. Addition of GSH non‐significantly (p = 0.1) improved mitochondrial membrane potential (MMP) (per cent) than control group. This study indicates that the addition of cysteine and GSH suggestive (p = 0.08) of reducing lipid peroxide levels. The conception rate (%) in glutathione group was significantly (p < 0.05) higher than that in cysteine (68 vs 58) and control (49) groups. The post‐thaw sperm progressive forward motility (r = 0.4) had moderate, but no significant correlation with conception rate. However, post‐thaw straight‐line velocity (r = 0.7), loss of acrosomal integrity (r = −0.8) and MMP (r = 0.9) had significant (p < 0.05) correlation with field fertility. This study indicates that the use of glutathione as semen additive may be used for improving post‐thaw semen quality and overall augmentation of pregnancy in cows.
Two Trebouxia algae with different physiological performances are ever‐present in lichen thalli of Ramalina farinacea. Coexistence versus Competition?
Authors: Casano Leonardo M. , del Campo Eva M. , García‐Breijo Francisco J. , Reig‐Armiñana José , Gasulla Francisco , del Hoyo Alicia , Guéra Alfredo , Barreno Eva 
Published: December 2010

Summary Ramalina farinacea is an epiphytic fruticose lichen that is relatively abundant in areas with Mediterranean, subtropical or temperate climates. Little is known about photobiont diversity in different lichen populations. The present study examines the phycobiont composition of several geographically distant populations of R. farinacea from the Iberian Peninsula, Canary Islands and California as well as the physiological performance of isolated phycobionts. Based on anatomical observations and molecular analyses, the coexistence of two different taxa of Trebouxia (working names, TR1 and TR9) was determined within each thallus of R. farinacea in all of the analysed populations. Examination of the effects of temperature and light on growth and photosynthesis indicated a superior performance of TR9 under relatively high temperatures and irradiances while TR1 thrived at moderate temperature and irradiance. Ramalina farinacea thalli apparently represent a specific and selective form of symbiotic association involving the same two Trebouxia phycobionts. Strict preservation of this pattern of algal coexistence is likely favoured by the different and probably complementary ecophysiological responses of each phycobiont, thus facilitating the proliferation of this lichen in a wide range of habitats and geographic areas.
The evolution of pedicellariae in echinoids: an arms race against pests and parasites
Authors: Coppard Simon E. , Kroh Andreas , Smith Andrew B. 
Published: December 2010

AbstractCoppard, S.E., Kroh, A. and Smith, A.B. (2010). The evolution of pedicellariae in echinoids: an arms race against pests and parasites. —Acta Zoologica (Stockholm) 00:1–24.Sea urchins (Echinoidea) have evolved a diverse array of jawed appendages termed pedicellariae to deter pests and predators. Pedicellarial structure and function are reviewed and their distribution mapped in 75 extant genera. Using a phylogeny of echinoids at family level constructed from 353 skeletal characters scored across 162 extant and fossil taxa, the evolution of pedicellarial form and function is reconstructed. For much of the Palaeozoic echinoids possessed a very restricted pedicellarial armament. By the early Mesozoic a diverse array of pedicellarial types had become established, implying that the threat from predators and pests markedly increased at this time. Since the Triassic, echinoids have continued to improve their defensive capability by evolving more effective venom delivery in globiferous pedicellariae, developing spatulate‐tips and curved blades for a more efficient grab in tridentate pedicellariae, and stouter, more robust valves with a stronger bite in ophicephalous pedicellariae to disable and remove ectoparasites. However, pedicellarial types are shown to be particularly prone to subsequent secondary loss, especially among infaunal echinoids, and thus have higher homoplasy levels than other phylogenetically useful skeletal structures.
Maintaining Legitimacy: Controversies, Orders of Worth, and Public Justifications
Authors: Patriotta Gerardo , Gond Jean‐Pascal , Schultz Friederike 
Published: December 2010

abstractWe build on Boltanski and Thévenot's theory of justification to account for the ways in which different stakeholder groups actively engage with discourses and objects to maintain the legitimacy of institutions that are relevant to their activity. We use this framework to analyse a controversy emerging from a nuclear accident which involved a large European energy company and sparked public debate on the legitimacy of nuclear power. Based on the findings, we elaborate a process model of institutional repair that explains the role of agents and the structural constraints they face in attempting to maintain legitimacy. The model enhances institutional understandings of legitimacy maintenance in three main respects: it proposes a view of legitimacy maintenance as a controversy‐based process progressing through stakeholders' justifications vis‐à‐vis a public audience; it demonstrates the role of meta‐level ‘orders of worth’ as multiple modalities for agreement which shape stakeholders' public justifications during controversies; and it highlights the capacities that stakeholders deploy in developing robust justifications out of a plurality of forms of agreement.
WHAKAPAPA, GENEALOGY AND GENETICS
Authors: EVANS DONALD 
Published: December 2010

ABSTRACTThis paper provides part of an analysis of the use of the Maori term whakapapa in a study designed to test the compatibility and commensurability of views of members of the indigenous culture of New Zealand with other views of genetic technologies extant in the country. It is concerned with the narrow sense of whakapapa as denoting biological ancestry, leaving the wider sense of whakapapa as denoting cultural identity for discussion elsewhere. The phenomenon of genetic curiosity is employed to facilitate this comparison. Four levels of curiosity are identified, in the Maori data, which penetrate more or less deeply into the psyche of individuals, affecting their health and wellbeing. These phenomena are compared with non‐Maori experiences and considerable commonalities are discovered together with a point of marked difference. The results raise important questions for the ethical application of genetic technologies.
BUOYS FOR ECCENTRIC EXISTENCE
Authors: BUCKLEY JAMES J. 
Published: December 2010

AbstractDavid Kelsey's Eccentric Existence argues that what we need is a “systematically unsystematic” account of human existence, a set of “buoys” or non‐negotiable convictions articulated on the basis of canonical Scriptures, leaving abundant room for philosophers and other non‐theologians to make their contributions. Embodied persons themselves/ourselves are constituted in three irreducibly complex canonically biblical narratives as creatures, reconciled, and consummated—although it is not always clear what aspects of these narratives are “buoys” and which are more negotiable. The God who constitutes embodied persons is the triune God of Nicaea (like a triple helix) who operates as one but in irreducibly distinct ways as Father and Son and Spirit—and cannot be mere instrument of human purposes. Kelsey intentionally leaves a number of Trinitarian and Christological questions open for further treatment, creating remarkable challenges for traditionalists and modernists alike.
The relevance of iron in the pathogenesis of Parkinson’s disease
Authors: Sian‐Hülsmann Jeswinder , Mandel Silvia , Youdim Moussa B. H. , Riederer Peter 
Published: December 2010

J. Neurochem. (2011) 118, 939–957.AbstractAlterations of iron levels in the brain has been observed and documented in a number of neurodegenerative disorders including Parkinson’s disease (PD). The elevated nigral iron levels observed in PD may reflect a dysfunction of brain iron homeostasis. Under normal physiological conditions excess iron can be sequestrated in ferritin and neuromelanin. Alternatively, the excess iron may represent a component of brain iron deposition associated with ageing. The aetiology of idiopathic PD largely remains an enigma. However, intensive investigations have provided a host of putative mechanisms that might contribute to the pathogenesis underlying the characteristic degeneration of the dopaminergic neurons in the substantia nigra (SN). The mechanisms proposed include oxidative (and nitrative) stress, inflammation, excitotoxicity, mitochondrial dysfunction, altered proteolysis and finally apoptotic induced cell death. Iron‐mediated cellular destruction is mediated primarily via reactive oxygen or/and nitrogen species induced oxidative stress. Furthermore, these pathogenic mechanisms appear to be closely interlinked to the cascade of events leading to cellular death. There are conflicting reports about the stage during disease progression at which nigral iron change occurs in PD. Some have found that there are no changes in iron content SN in asymptomatic incidental Lewy body disease, suggesting it may represent a secondary event in the cascade of neuronal degeneration. In contrast, others have found an elevation of iron in SN in pre‐clinical stages. These discrepancies may be attributed to the occurrence of different sub‐groups of the disease. This concurs with the notion that PD represents a group of related diseases with a number of potential pathogenic pathways.
Sorghum Insect Problems and ManagementF
Authors: Guo Chunshan , Cui Wei , Feng Xue , Zhao Jianzhou , Lu Guihua 
Published: December 2010

Abstract Sorghum (Sorghum bicolor) has high levels of starch, sugar, and fiber and is one of the most important energy crops in the world. Insect damage is one of the challenges that impacts sorghum biomass production. There are at least 150 insect species that can infest sorghum varieties worldwide. These insects can complete several generations within a growing season, they target various parts of sorghum plants at developmental stages, and they cause significant biomass losses. Genetic research has revealed the existence of resistant genetics in sorghum and insect tolerant sorghum varieties have been identified. Various control methods have been developed, yet more effective management is needed for increasing sorghum biomass production. Although there are no transgenic sorghum products on the market yet, biotechnology has been recognized as an important tool for controlling insect pests and increasing sorghum production.
Know Your Standard: Clarifying the CIE Erythema Action Spectrum
Authors: Webb Ann R. , Slaper Harry , Koepke Peter , Schmalwieser Alois W. 
Published: December 2010

AbstractThe standard erythema action spectrum provides an internationally accepted representation of the erythema‐inducing effectiveness of wavelengths in the UV part of the spectrum. The action spectrum forms the basis of the UV index used for public health information, defines the standard erythema dose unit and the minimum erythema dose and is the default response spectrum aspired to by a range of UV radiometer manufacturers. However, there are several versions of this erythema action spectrum in use, and only one of them has been endorsed as a standard. While the differences in erythemally weighted radiation incurred by choice of action spectrum will be no more than a few percent, this uncertainty is unnecessary. Here we detail the differences in the different versions of erythema action spectra, illustrate the resulting effects in quantifying UV doses and encourage readers to use only the standard version of the action spectrum in the future.
Dental implant tourism
Authors: Barrowman RA , Grubor D , Chandu A 
Published: December 2010

AbstractAccess and affordability of dental care can be problematic for some in the Australian community. Therefore, dental tourism is increasingly becoming more attractive to some patients due to decreased expense, increased convenience and immediacy of treatment. However, there are significant issues for both clinician and patient in regards to dental tourism. Lack of accountability and regulation are the main issues and this is particularly evident when complications occur. This paper presents five cases where complications have arisen in the setting of dental tourism.
Role of glycogen availability in sarcoplasmic reticulum Ca2+ kinetics in human skeletal muscle
Authors: Ørtenblad Niels , Nielsen Joachim , Saltin Bengt , Holmberg Hans‐Christer 
Published: December 2010

Non‐technical summaryGlucose is stored as glycogen in skeletal muscle. The importance of glycogen as a fuel during exercise has been recognized since the 1960s; however, little is known about the precise mechanism that relates skeletal muscle glycogen to muscle fatigue. We show that low muscle glycogen is associated with an impairment of muscle ability to release Ca2+, which is an important signal in the muscle activation. Thus, depletion of glycogen during prolonged, exhausting exercise may contribute to muscle fatigue by causing decreased Ca2+ release inside the muscle. These data provide indications of a signal that links energy utilization, i.e. muscle contraction, with the energy content in the muscle, thereby inhibiting a detrimental depletion of the muscle energy store.
Skeletal muscle fatigue precedes the slow component of oxygen uptake kinetics during exercise in humans
Authors: Cannon Daniel T. , White Ailish C. , Andriano Melina F. , Kolkhorst Fred W. , Rossiter Harry B. 
Published: December 2010

Non‐technical summaryThe mechanisms determining exercise intolerance are poorly understood. A reduction in work efficiency in the form of an additional energy cost and oxygen requirement occurs during high‐intensity exercise and contributes to exercise limitation. Muscle fatigue and subsequent recruitment of poorly efficient muscle fibres has been proposed to mediate this decline. These data demonstrate in humans, that muscle fatigue, generated in the initial minutes of exercise, is correlated with the increasing energy demands of high‐intensity exercise. Surprisingly, however, while muscle fatigue reached a plateau, oxygen uptake continued to increase throughout 8 min of exercise. This suggests that additional recruitment of inefficient muscle fibres may not be the sole mechanism contributing to the decline in work efficiency during high‐intensity exercise.
Comparative Effects of Carbapenems on Bacterial Load and Host Immune Response in aKlebsiella pneumoniaeMurine Pneumonia Model
Authors: Hilliard Jamese J. , Melton John L. , Hall LeRoy , Abbanat Darren , Fernandez Jeffrey , Ward Christine K. , Bunting Rachel A. , Barron A. , Lynch A. Simon , Flamm Robert K. 
Published: December 2010

ABSTRACTDoripenem is a carbapenem with potent broad-spectrum activity against Gram-negative pathogens, including antibiotic-resistantEnterobacteriaceae. As the incidence of extended-spectrum β-lactamase (ESBL)-producing Gram-negative bacilli is increasing, it was of interest to examine thein vivocomparative efficacy of doripenem, imipenem, and meropenem against aKlebsiella pneumoniaeisolate expressing the TEM-26 ESBL enzyme. In a murine lethal lower respiratory infection model, doripenem reduced theKlebsiellalung burden by 2 log10CFU/g lung tissue over the first 48 h of the infection. Treatment of mice with meropenem or imipenem yielded reductions of approximately 1.5 log10CFU/g during this time period. Seven days postinfection,Klebsiellatiters in the lungs of treated mice decreased an additional 2 log10CFU/g relative to those in the lungs of untreated control animals. Lipopolysaccharide (LPS) endotoxin release assays indicated that 6 h postinfection, meropenem- and imipenem-treated animals had 10-fold more endotoxin in lung homogenates and sera than doripenem-treated mice. Following doripenem treatment, the maximum endotoxin release postinfection (6 h) was 53,000 endotoxin units (EU)/ml, which was 2.7- and 6-fold lower than imipenem or meropenem-treated animals, respectively. While the levels of several proinflammatory cytokines increased in both the lungs and sera following intranasalK. pneumoniaeinoculation, doripenem treatment, but not meropenem or imipenem treatment, resulted in significantly increased interleukin 6 levels in lung homogenates relative to those in lung homogenates of untreated controls, which may contribute to enhanced neutrophil killing of bacteria in the lung. Histological examination of tissue sections indicated less overall inflammation and tissue damage in doripenem-treated mice, consistent with improved antibacterial efficacy, reduced LPS endotoxin release, and the observed cytokine induction profile.
Tigecycline Exhibits Inhibitory Activity against
Clostridium difficile
in the Colon of Mice and Does Not Promote Growth or Toxin Production
Authors: Jump Robin L. P. , Li Yuejin , Pultz Michael J. , Kypriotakis Georgios , Donskey Curtis J. 
Published: December 2010

ABSTRACT

Tigecycline is a broad-spectrum glycylcycline antibiotic with potent
in vitro
activity against
Clostridium difficile
. We used a mouse model to test the hypothesis that tigecycline has a low propensity to promote colonization and toxin production by
C. difficile
due to inhibitory activity in the colon. Mice (5 to 8 per group) received subcutaneous injections of tigecycline (low and high doses) alone or in combination with clindamycin for 6 days. Growth of and toxin production by 3 strains of
C. difficile
(tigecycline MICs ≤ 0.012 μg/ml) were measured in cecal contents collected 6 h or 3 days after the final antibiotic dose. Antibiotic concentrations were measured using a bioassay, and concentrations of total anaerobes and
Bacteroides
spp. were measured. The effects of tigecycline on rendering mice susceptible to colonization with and reducing the burden of
C. difficile
were also examined. In comparison to saline controls, clindamycin promoted the growth of
C. difficile
(
P
< 0.001) in cecal contents, whereas tigecycline did not. Tigecycline did not suppress total anaerobes or
Bacteroides
spp. in comparison to saline controls. Concurrent administration of tigecycline prevented clindamycin-induced promotion of
C. difficile
in cecal contents collected 6 h or 3 days (high dose only) after the final antibiotic dose. Tigecycline did not promote the establishment of colonization in mice, yet it did not reduce concentrations of
C. difficile
in animals with established colonization. In summary, tigecycline did not promote the growth of or toxin production by
C. difficile
, probably due to inhibitory activity against
C. difficile
and relative sparing of indigenous anaerobic microflora.