bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional analysis of the group A streptococcal luxS/AI-2 system in metabolism, adaptation to stress and interaction with host cells
Authors: Siller Maria , Janapatla Rajendra P , Pirzada Zaid A , Hassler Christine , Zinkl Daniela , Charpentier Emmanuelle 
Published: October 2008

Abstract

Background
The luxS/AI-2 signaling pathway has been reported to interfere with important physiological and pathogenic functions in a variety of bacteria. In the present study, we investigated the functional role of the streptococcal luxS/AI-2 system in metabolism and diverse aspects of pathogenicity including the adaptation of the organism to stress conditions using two serotypes of Streptococcus pyogenes, M1 and M19.

Results
Exposing wild-type and isogenic luxS-deficient strains to sulfur-limited media suggested a limited role for luxS in streptococcal activated methyl cycle metabolism. Interestingly, loss of luxS led to an increased acid tolerance in both serotypes. Accordingly, luxS expression and AI-2 production were reduced at lower pH, thus linking the luxS/AI-2 system to stress adaptation in S. pyogenes. luxS expression and AI-2 production also decreased when cells were grown in RPMI medium supplemented with 10% serum, considered to be a host environment-mimicking medium. Furthermore, interaction analysis with epithelial cells and macrophages showed a clear advantage of the luxS-deficient mutants to be internalized and survive intracellularly in the host cells compared to the wild-type parents. In addition, our data revealed that luxS influences the expression of two virulence-associated factors, the fasX regulatory RNA and the virulence gene sibA (psp).

Conclusion
Here, we suggest that the group A streptococcal luxS/AI-2 system is not only involved in the regulation of virulence factor expression but in addition low level of luxS expression seems to provide an advantage for bacterial survival in conditions that can be encountered during infections.
Involvement of a phospholipase C in the hemolytic activity of a clinical strain of Pseudomonas fluorescens
Authors: Rossignol Gaelle , Merieau Annabelle , Guerillon Josette , Veron Wilfried , Lesouhaitier Olivier , Feuilloley Marc GJ , Orange Nicole 
Published: October 2008

Abstract

Background

Pseudomonas fluorescens is a ubiquitous Gram-negative bacterium frequently encountered in hospitals as a contaminant of injectable material and surfaces. This psychrotrophic bacterium, commonly described as unable to grow at temperatures above 32°C, is now considered non pathogenic. We studied a recently identified clinical strain of P. fluorescens biovar I, MFN1032, which is considered to cause human lung infection and can grow at 37°C in laboratory conditions.

Results
We found that MFN1032 secreted extracellular factors with a lytic potential at least as high as that of MF37, a psychrotrophic strain of P. fluorescens or the mesophilic opportunistic pathogen, Pseudomonas aeruginosa PAO1. We demonstrated the direct, and indirect – through increases in biosurfactant release – involvement of a phospholipase C in the hemolytic activity of this bacterium. Sequence analysis assigned this phospholipase C to a new group of phospholipases C different from those produced by P. aeruginosa. We show that changes in PlcC production have pleiotropic effects and that plcC overexpression and plcC extinction increase MFN1032 toxicity and colonization, respectively.

Conclusion
This study provides the first demonstration that a PLC is involved in the secreted hemolytic activity of a clinical strain of Pseudomonas fluorescens. Moreover, this phospholipase C seems to belong to a complex biological network associated with the biosurfactant production.
Prognostic parameters for recurrence of papillary thyroid microcarcinoma
Authors: Kim Tae Yong , Hong Suck Joon , Kim Jung Min , Gu Kim Won , Gong Gyungyub , Ryu Jin Sook , Kim Won Bae , Yun Sung-Cheol , Shong Young Kee 
Published: October 2008

Abstract

Background
Papillary thyroid microcarcinoma (PTMC) is defined as a papillary thyroid carcinoma less than or equal to 1.0 cm in size. Independent prognostic factors for clinical recurrence of PTMC have not been clearly delineated.

Methods
Clinicopathological parameters predicting PTMC recurrence were determined by retrospective analysis of 307 patients.

Results
Of the 293 patients eligible for analysis, 14 (5%) had recurrence during a median follow-up time of 65 months. Recurrence was observed in 8 of 166 patients (0.5%) treated with total or near-total thyroidectomy; gender (P = 0.02) and presence of lateral cervical node metastases at initial surgery (P = 0.01) were associated with recurrence. Six of the 127 patients (0.5%) treated with hemi- or subtotal thyroidectomy experience recurrences, but no significant prognostic factor for recurrence was identified. Multivariate Cox-regression analysis showed that gender and cervical lymph node metastasis were significant variables

Conclusion
PTMC showed very diverse disease extent and could not be regarded as indolent, relatively benign disease based on the primary tumor size. The extent of surgery should be based on prognostic parameters, such as gender and lateral neck node metastasis, in patients with PTMC.
Recombinant amyloid beta-peptide production by coexpression with an affibody ligand
Authors: Macao Bertil , Hoyer Wolfgang , Sandberg Anders , Brorsson Ann-Christin , Dobson Christopher M , Härd Torleif 
Published: October 2008

Abstract

Background
Oligomeric and fibrillar aggregates of the amyloid β-peptide (Aβ) have been implicated in the pathogenesis of Alzheimer's disease (AD). The characterization of Aβ assemblies is essential for the elucidation of the mechanisms of Aβ neurotoxicity, but requires large quantities of pure peptide. Here we describe a novel approach to the recombinant production of Aβ. The method is based on the coexpression of the affibody protein ZAβ3, a selected affinity ligand derived from the Z domain three-helix bundle scaffold. ZAβ3 binds to the amyloidogenic central and C-terminal part of Aβ with nanomolar affinity and consequently inhibits aggregation.

Results
Coexpression of ZAβ3 affords the overexpression of both major Aβ isoforms, Aβ(1–40) and Aβ(1–42), yielding 4 or 3 mg, respectively, of pure 15N-labeled peptide per liter of culture. The method does not rely on a protein-fusion or -tag and thus does not require a cleavage reaction. The purified peptides were characterized by NMR, circular dichroism, SDS-PAGE and size exclusion chromatography, and their aggregation propensities were assessed by thioflavin T fluorescence and electron microscopy. The data coincide with those reported previously for monomeric, largely unstructured Aβ. ZAβ3 coexpression moreover permits the recombinant production of Aβ(1–42) carrying the Arctic (E22G) mutation, which causes early onset familial AD. Aβ(1–42)E22G is obtained in predominantly monomeric form and suitable, e.g., for NMR studies.

Conclusion
The coexpression of an engineered aggregation-inhibiting binding protein offers a novel route to the recombinant production of amyloidogenic Aβ peptides that can be advantageously employed to study the molecular basis of AD. The presented expression system is the first for which expression and purification of the aggregation-prone Arctic variant (E22G) of Aβ(1–42) is reported.
Lung responses to secondary endotoxin challenge in rats exposed to pig barn air
Authors: Charavaryamath Chandrashekhar , Keet Taryn , Aulakh Gurpreet K , Townsend Hugh GG , Singh Baljit 
Published: October 2008

AbstractBackgroundSwine barn air contains endotoxin and many other noxious agents. Single or multiple exposures to pig barn air induces lung inflammation and loss of lung function. However, we do not know the effect of exposure to pig barn air on inflammatory response in the lungs following a secondary infection. Therefore, we tested a hypothesis that single or multiple exposures to barn air will result in exaggerated lung inflammation in response to a secondary insult withEscherichia coliLPS (E. coliLPS).MethodsWe exposed Sprague-Dawley rats to ambient (N = 12) or swine barn air (N = 24) for one or five days and then half (N = 6/group) of these rats received intravenousE. coliLPS challenge, observed for six hours and then euthanized to collect lung tissues for histology, immunohistochemistry and ELISA to assess lung inflammation.ResultsCompared to controls, histological signs of lung inflammation were evident in barn exposed rat lungs. Rats exposed to barn air for one or five days and challenged withE. coliLPS showed increased recruitment of granulocytes compared to those exposed only to the barn. Control, one and five day barn exposed rats that were challenged withE. coliLPS showed higher levels of IL-1β in the lungs compared to respective groups not challenged withE. coliLPS. The levels of TNF-α in the lungs did not differ among any of the groups. Control rats withoutE. coliLPS challenge showed higher levels of TGF-β2 compared to controls challenged withE. coliLPS.ConclusionThese results show that lungs of rats exposed to pig barn air retain the ability to respond toE. coliLPS challenge.
A case of polymyositis associated with papillary thyroid cancer: a case report
Authors: Kalliabakos Dimitrios , Pappas Apostolos , Lagoudianakis Emmanuel , Papadima Artemisia , Chrysikos John , Basagiannis Christos , Tsakoumagou Maria , Skanelli Yasemi , Manouras Andreas 
Published: October 2008

Abstract
Differentiated thyroid cancer is rarely associated with paraneoplastic events. Polymyositis, an autoimmune inflammatory myopathy, can be manifested as a paraneoplastic syndrome (PS). We report a case of a young woman who developed progressive proximal muscle weakness one and a half year after a total thyroidectomy for papillary thyroid cancer. Clinical features, laboratory results and muscle biopsy led us to the diagnosis of polymyositis, possibly related to her previous malignancy. A search for recurrence of the thyroid carcinoma or other underlying malignancy was fruitless. The patient improved slowly but almost completely after about 6 months of immunosupressive therapy, which she is still receiving.
In-situ Fatigue Damage Investigations in Welded Metallic Components by Infrared Techniques
Authors: Medgenberg Justus , Ummenhofer Thomas 
Published: October 2008

Abstract
The paper reviews the state of the art of thermal damage assessment in metals and proposes a specialized form of lock-in thermography as an efficient tool for the quantification of early fatigue damage phenomena in welded steel structures in the regime of mid- to high-cycle fatigue. It can be proved that advanced thermographic techniques are sensitive to early damage phenomena in the weld toe. They provide a new experimental mean for in-situ investigation of early inhomogeneous fatigue damage phenomena as mesoplasticity and fatigue cracks. The results demonstrate that non-contacting full field temperature measurements using highly sensitive infrared technology can be applied successfully to detect localized fatigue damage at around 10 % to 20 % of the total fatigue lifetime of the tested specimens. The applied method is based on the separation of thermoelastic and thermoplastic temperature effects which cause characteristic local temperature signatures. In contrast to other well-known approaches—as, e.g., measuring the rise of mean temperature during fatigue loading—the applied method offers a very high spatial resolution and resolves extremely localized phenomena. The methodology can be applied to monitor the fatigue process during conventional fatigue testing. The additional effort for the specimen preparation and the installation of the testing setup is minimal.
Quantitative Trait Locus Mapping Can Benefit From Segregation Distortion
Authors: Xu Shizhong 
Published: October 2008

Abstract
Segregation distortion is a phenomenon that has been observed in many experimental systems. How segregation distortion among markers arises and its impact on mapping studies are the focus of this work. Segregation distortion of markers can be considered to arise from segregation distortion loci (SDL). I develop a theory of segregation distortion and show that the presence of only a few SDL can cause the entire chromosome to distort from Mendelian segregation. Segregation distortion is detrimental to the power of detecting quantitative trait loci (QTL) with dominance effects, but it is not always a detriment to QTL mapping for additive effects. When segregation distortion of a locus is a random event, the SDL is beneficial to QTL mapping ∼44% of the time. If SDL are present and ignored, power loss can be substantial. A dense marker map can be used to ameliorate the situation, and if dense marker information is incorporated, power loss is minimal. However, other situations are less benign. A method that can simultaneously map QTL and SDL is discussed, maximizing both use of mapping resources and use by agricultural and evolutionary biologists.
Drosophila Hold'em Is Required for a Subset of Meiotic Crossovers and Interacts With the DNA Repair Endonuclease Complex Subunits MEI-9 and ERCC1
Authors: Joyce Eric F , Tanneti S Nikhila , McKim Kim S 
Published: October 2008

Abstract
Three Drosophila proteins, ERCC1, MUS312, and MEI-9, function in a complex proposed to resolve double-Holliday-junction intermediates into crossovers during meiosis. We report here the characterization of hold'em (hdm), whose protein product belongs to a single-strand-DNA-binding superfamily of proteins. Mutations in hdm result in reduced meiotic crossover formation and sensitivity to the DNA-damaging agent methyl methanesulfonate. Furthermore, HDM physically interacts with both MEI-9 and ERCC1 in a yeast two-hybrid assay. We conclude that HDM, MEI-9, MUS312, and ERCC1 form a complex that resolves meiotic recombination intermediates into crossovers.
Drosophila PCH2 Is Required for a Pachytene Checkpoint That Monitors Double-Strand-Break-Independent Events Leading to Meiotic Crossover Formation
Authors: Joyce Eric F , McKim Kim S 
Published: October 2008

AbstractDuring meiosis, programmed DNA double-strand breaks (DSBs) are repaired to create at least one crossover per chromosome arm. Crossovers mature into chiasmata, which hold and orient the homologous chromosomes on the meiotic spindle to ensure proper segregation at meiosis I. This process is usually monitored by one or more checkpoints that ensure that DSBs are repaired prior to the meiotic divisions. We show here that mutations in Drosophila genes required to process DSBs into crossovers delay two important steps in meiotic progression: a chromatin-remodeling process associated with DSB formation and the final steps of oocyte selection. Consistent with the hypothesis that a checkpoint has been activated, the delays in meiotic progression are suppressed by a mutation in the Drosophila homolog of pch2. The PCH2-dependent delays also require proteins thought to regulate the number and distribution of crossovers, suggesting that this checkpoint monitors events leading to crossover formation. Surprisingly, two lines of evidence suggest that the PCH2-dependent checkpoint does not reflect the accumulation of unprocessed recombination intermediates: the delays in meiotic progression do not depend on DSB formation or on mei-41, the Drosophila ATR homolog, which is required for the checkpoint response to unrepaired DSBs. We propose that the sites and/or conditions required to promote crossovers are established independently of DSB formation early in meiotic prophase. Furthermore, the PCH2-dependent checkpoint is activated by these events and pachytene progression is delayed until the DSB repair complexes required to generate crossovers are assembled. Interestingly, PCH2-dependent delays in prophase may allow additional crossovers to form.
Drosophila and Vertebrate Casein Kinase Iδ Exhibits Evolutionary Conservation of Circadian Function
Authors: Fan Jin-Yuan , Preuss Fabian , Muskus Michael J , Bjes Edward S , Price Jeffrey L 
Published: October 2008

AbstractMutations lowering the kinase activity of Drosophila Doubletime (DBT) and vertebrate casein kinase Iε/δ (CKIε/δ) produce long-period, short-period, and arrhythmic circadian rhythms. Since most ckI short-period mutants have been isolated in mammals, while the long-period mutants have been found mostly in Drosophila, lowered kinase activity may have opposite consequences in flies and vertebrates, because of differences between the kinases or their circadian mechanisms. However, the results of this article establish that the Drosophila dbt mutations have similar effects on period (PER) protein phosphorylation by the fly and vertebrate enzymes in vitro and that Drosophila DBT has an inhibitory C-terminal domain and exhibits autophosphorylation, as does vertebrate CKIε/δ. Moreover, expression of either Drosophila DBT or the vertebrate CKIδ kinase carrying the Drosophila dbtS or vertebrate tau mutations in all circadian cells leads to short-period circadian rhythms. By contrast, vertebrate CKIδ carrying the dbtL mutation does not lengthen circadian rhythms, while Drosophila DBTL does. Different effects of the dbtS and tau mutations on the oscillations of PER phosphorylation suggest that the mutations shorten the circadian period differently. The results demonstrate a high degree of evolutionary conservation of fly and vertebrate CKIδ and of the functions affected by their period-shortening mutations.
Evaluation of Replacement Feeds for the Fry Feed Kyowa for Larval Walleyes
Authors: Johnson J Alan , Summerfelt Robert C , Clayton Richard D 
Published: October 2008

Abstract
Because Fry Feed Kyowa (FFK) was the standard and the only commercially manufactured starter feed suitable for intensive culture of larval walleyes Sander vitreus, it became imperative to evaluate other commercial feeds after FFK importation to the USA was banned to prevent the spread of bovine spongiform encephalopathy. A project was undertaken at the Rathbun Fish Culture Research Facility (Rathbun), Moravia, Iowa, and Iowa State University (ISU), Ames, using a single-factor experimental design with Lansy and Epac feeds (INVE Aquaculture, Inc., Ogden, Utah) and Gemma feed (Skretting, Vancouver, British Columbia). Walleyes were cultured at both sites from 3 to 28 d posthatch to evaluate the feeds. Performance indicators included presence of feed in gut, gas bladder inflation, survival, total length (mm), weight (mg), growth rate, and incidence of deformities. At both sites, survival was 2.6–3.6 times greater for fish given Gemma than for fish given the INVE feeds; the difference was significant at Rathbun but not at ISU. Length, weight, and growth rate at both sites were also significantly greater for Gemma-fed walleyes than for INVE-fed fish. Weight advantage produced by Gemma was 192% at ISU and 534% at Rathbon. Performance measures of fish given Gemma were similar to those of fish fed FFK in previous years.
Red King Crab Mating Success, Sex Ratio, Spatial Distribution, and Abundance Estimates as Artifacts of Survey Timing in Bristol Bay, Alaska
Authors: Dew C. Braxton 
Published: October 2008

Abstract
The Bristol Bay, Alaska, fishery for red king crab Paralithodes camtschaticus is a male-only fishery. A safeguard against male overfishing is the requirement that at least 8.4 million successfully mated, newly fertilized females be present on the grounds each year; otherwise no harvest is permitted. Estimation of the number of mated females in the population is complicated by the timing of the Bering Sea trawl survey, which in most years moves through Bristol Bay before red king crab spawning is complete. From 1977 through 2000, an average of 22% (range, 0–87%) of the broodstock remained unmated at the time of the May–June survey. Eighty-nine percent of the observed annual variation in the proportion of unmated crabs was explained by water temperature and the date of the survey. Thus, the degree of mating success shown by each year's survey, although influenced by male availability, is predominantly an artifact of temperature and survey timing. Also, red king crabs tend to spawn in untrawlable nearshore waters, increasing the difficulty of obtaining unbiased estimates of abundance from sampling an open population. Because the proportion of mature females that emigrate each year to the nearshore spawning grounds is greater than that of males, the sex ratio within the sampled region of a survey conducted during spawning is biased toward males. This bias masks one of the more obvious signs of male overharvest—a male-depauperate sex ratio. Finally, a survey conducted during spawning cannot provide an accurate mapping of the spatial distribution of the postspawning broodstock returning from inshore spawning grounds to incubate their newly fertilized eggs during the next 10–12 months. A time–temperature model indicated that delaying the Bristol Bay red king crab survey until the end of June would ameliorate the problems caused by sampling an open population engaged in spawning.
Exploring the Use of a Size-Based Egg-per-Recruit Model for the Red Abalone Fishery in California
Authors: Leaf Robert T. , Rogers-Bennett Laura , Jiao Yan 
Published: October 2008

Abstract
Eggs-per-recruit (EPR) models are widely used for management of invertebrate fisheries to provide guidance to managers about the magnitude of egg production for a given level of instantaneous annual fishing mortality (F). We constructed a deterministic size-based EPR model that utilizes size-specific natural mortality rates and egg production for red abalone Haliotis rufescens in California. We analyzed the sensitivity of the model to alterations in biological parameters, modeled the effect of incidental mortality of sublegal individuals on EPR, and modeled the effects of various management actions, including incorporation of a slot size limit, incorporation of a harvest refugium, and alternative legal minimum size limits. Model results were more sensitive to alterations in growth parameters and lower mortality estimates than to changes in upper mortality estimates or fecundity parameters. When F increased from 0.0 to 0.1 per year, EPR exhibited a large decline from 100% to 70%. Only the incorporation of a harvest refugium and an increase in the minimum size limit produced increases in the percent of maximum EPR. Implementing a slot limit of 152.4–203.2 mm maximum shell length (MSL) decreased the EPR value, indicating the importance of egg production by red abalone that are smaller than the current minimum size limit of 177.8 mm MSL. Because of the sensitivity of model predictions to changes in certain biological parameters, we recommend caution when applying EPR models to management, particularly for regions without spatially explicit parameter values. Despite this sensitivity, EPR models provide a heuristic framework for exploring the potential impacts of proposed fishery management strategies (e.g., harvest refugia), establishing biological reference points, examining how spatial and temporal variability in biological parameters affects egg production, and providing a guide for prioritizing research to improve data quality used for red abalone management.