bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assaying proline hydroxylation in recombinant collagen variants by liquid chromatography-mass spectrometry
Authors: Chan S W Polly , Greaves John , Da Silva Nancy A , Wang Szu-Wen 
Published: August 2012

Abstract

Background
The fabrication of recombinant collagen and its prescribed variants has enormous potential in tissue regeneration, cell-matrix interaction investigations, and fundamental biochemical and biophysical studies of the extracellular matrix. Recombinant expression requires proline hydroxylation, a post-translational modification which is critical for imparting stability and structure. However, these modifications are not native to typical bacterial or yeast expression systems. Furthermore, detection of low levels of 4-hydroxyproline is challenging with respect to selectivity and sensitivity.

Results
We have developed a new liquid chromatography-mass spectrometry (LC-MS) method to evaluate proline hydroxylation in recombinant collagen. This assay was tested in different Saccharomyces cerevisiae expression systems to evaluate the effect of gene ratio between prolyl-4-hydroxylase and collagen on the extent of hydroxylation. These systems used a human collagen III gene that was synthesized de novo from oligonucleotides. The LC-MS assay does not require derivatization, uses only picomoles of sample, and can measure proline hydroxylation levels in recombinant and native collagen ranging from approximately 0% to 40%. The hydroxylation values obtained by LC-MS are as accurate and as precise as those obtained with the conventional method of amino acid analysis.

Conclusions
A facile, derivatization-free LC-MS method was developed that accurately determines the percentage of proline hydroxylation in different yeast expression systems. Using this assay, we determined that systems with a higher collagen-to-hydroxylase gene copy ratio yielded a lower percentage of hydroxylation, suggesting that a specifically balanced gene ratio is required to obtain higher hydroxylation levels.
Phenolic content, antioxidant effect and cytotoxic activity of Leea indica leaves
Authors: Reddy Nidyaletchmy Subba , Navanesan Suerialoasan , Sinniah Saravana Kumar , Wahab Norhanom Abdul , Sim Kae Shin 
Published: August 2012

Abstract

Background
The leaves of Leea indica (Vitaceae), commonly known as ‘Huo Tong Shu’ in Malaysia, have been traditionally used as natural remedy in folk medicine by the locals. The current study reports the outcome of antioxidant and cytotoxic investigation of L. indica leaves. To the best of our knowledge, this is the first report of L. indica leaf crude ethanol and its fractionated extracts (hexane, ethyl acetate and water) for evaluation of total phenolic content, antioxidant effect and cytotoxic activity against colon cancer cell lines.

Methods
In the present study, L. indica leaf crude ethanol and its fractionated extracts (hexane, ethyl acetate and water) were firstly prepared prior to phenolic content, antioxidant effect and cytotoxic activity assessment. Folin-Ciocalteau’s method was used for the measurement of total phenolic content of the extracts. The antioxidant activity was measured by employing three different established testing systems, such as scavenging activity on DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals, reducing power assay and SOD (superoxide dismutase) activity assay. The cytotoxic activity of the extracts were evaluated against three colon cancer cell lines with varying molecular characteristics (HT-29, HCT-15 and HCT-116) by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay.

Results
The total phenolic content and antioxidant capabilities differed significantly among the L. indica leaf extracts. A strong correlation between total phenolic content and antioxidant properties was found, indicating that phenolic compounds are the major contributor to the antioxidant properties of these extracts. Among the crude ethanol and its fractionated extracts, fractionated water extract showed significantly the highest total phenolic content and strongest antioxidant effect in all the antioxidant testing systems employed in this study. All the four extracts exert no damage to the selected colon cancer cells.

Conclusions
The data obtained in these testing systems clearly establish the antioxidant potency of the fractionated water extract of L. indica leaves. Additional studies should be carried out to isolate and identify the bioactive compounds in the fractionated water extract, in order to provide more convincing evidence.
Ultraviolet-ozone-treated PEDOT:PSS as anode buffer layer for organic solar cells
Authors: Su Zisheng , Wang Lidan , Li Yantao , Zhao Haifeng , Chu Bei , Li Wenlian 
Published: August 2012

Abstract
Ultraviolet-ozone-treated poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)was used as the anode buffer layer in copper phthalocyanine (CuPc)/fullerene-based solar cells. The power conversion efficiency of the cells with appropriated UV-ozone treatment was found to increase about 20% compared to the reference cell. The improved performance is attributed to the increased work function of the PEDOT:PSS layer, which improves the contact condition between PEDOT:PSS and CuPc, hence increasing the extraction efficiency of the photogenerated holes and decreasing the recombination probability of holes and electrons in the active organic layers.
Template method for fabricating interdigitate p-n heterojunction for organic solar cell
Authors: Hu Jianchen , Shirai Yasuhiro , Han Liyuan , Wakayama Yutaka 
Published: August 2012

Abstract
Anodic aluminum oxide (AAO) templates are used to fabricate arrays of poly(3-hexylthiophene) (P3HT) pillars. This technique makes it possible to control the dimensions of the pillars, namely their diameters, intervals, and heights, on a tens-of-nanometer scale. These features are essential for enhancing carrier processes such as carrier generation, exciton diffusion, and carrier dissociation and transport. An interdigitated p-n junction between P3HT pillars and fullerene (C60) exhibits a photovoltaic effect. Although the device properties are still preliminary, the experimental results indicate that an AAO template is an effective tool with which to develop organic solar cells because highly regulated nanostructures can be produced on large areas exceeding 100 mm2.
Clonal analysis and virulent traits of pathogenic extraintestinal Escherichia coliisolates from swine in China
Authors: Ding Yi , Tang Xibiao , Lu Ping , Wu Bin , Xu Zhuofei , Liu Wugang , Zhang Ruixuan , Bei Weicheng , Chen Huanchun , Tan Chen 
Published: August 2012

Abstract

Background
Extraintestinal pathogenic Escherichia coli (ExPEC) can cause a variety of infections outside the gastrointestinal tract in humans and animals. Infections due to swine ExPECs have been occurring with increasing frequency in China. These ExPECs may now be considered a new food-borne pathogen that causes cross-infections between humans and pigs. Knowledge of the clonal structure and virulence genes is needed as a framework to improve the understanding of phylogenetic traits of porcine ExPECs.

Results
Multilocus sequence typing (MLST) data showed that the isolates investigated in this study could be placed into four main clonal complexes, designated as CC10, CC1687, CC88 and CC58. Strains within CC10 were classified as phylogroup A, and these accounted for most of our porcine ExPEC isolates. Isolates in the CC1687 clonal complex, formed by new sequence types (STs), was classified as phylogroup D, with CC88 isolates considered as B2 and CC58 isolates as B1. Porcine ExPECs in these four clonal complexes demonstrated significantly different virulence gene patterns. A few porcine ExPECs were indentified in phylogroup B2, the phylogroup in which human ExPECs mainly exist. However some STs in the four clonal groups of porcine ExPECs were reported to cause extraintestinal infections in human, based on data in the MLST database.

Conclusion
Porcine ExPECs have different virulence gene patterns for different clonal complexes. However, these strains are mostly fell in phylogenentic phylogroup A, B1 and D, which is different from human ExPECs that concentrate in phylogroup B2. Our findings provide a better understanding relating to the clonal structure of ExPECs in diseased pigs and indicate a need to re-evaluate their contribution to human ExPEC diseases.
Centrosome loss or amplification does not dramatically perturb global gene expression inDrosophila
Authors: Baumbach Janina , Levesque Mitchell P. , Raff Jordan W. 
Published: August 2012

SummaryCentrosome defects are a common feature of many cancers, and they can predispose fly brain cells to form tumours. In flies, centrosome defects perturb the asymmetric division of the neural stem cells, but it is unclear how this might lead to malignant transformation. One possibility is that centrosome defects might also perturb cellular homeostasis: for example, stress pathways are often activated in response to centrosome defects in cultured cells, and stress contributes to tumourigenesis in some fly models. Here we attempt to assess whether centrosome loss or centrosome amplification perturbs cell physiology in vivo by profiling the global transcriptome of Drosophila larval brains and imaginal discs that either lack centrosomes or have too many centrosomes. Surprisingly, we find that centrosome loss or amplification leads to few changes in the transcriptional profile of these cells, indicating that centrosome defects are surprisingly well tolerated by these cells. These observations indicate that centrosome defects can predispose fly brain cells to form tumours without, at least initially, dramatically altering their physiology.
Spermatogenesis arrest caused by conditional deletion of Hsp90α in adult mice
Authors: Kajiwara Chiaki , Kondo Shiho , Uda Shizuha , Dai Lei , Ichiyanagi Tomoko , Chiba Tomoki , Ishido Satoshi , Koji Takehiko , Udono Heiichiro 
Published: August 2012

Summary
It is controversial whether a functional androgen receptor (AR) on germ cells, including spermatogonia, is essential for their development into sperm and, thus, initiation and maintenance of spermatogenesis. It was recently shown that many spermatocytes underwent apoptosis in the testes of Hsp90α KO mice. We had generated Hsp90α KO mice independently and confirmed this phenotype. However, the important question of whether Hsp90α is required to maintain spermatogenesis in adult mice in which testicular maturation is already completed could not be addressed using these conventional KO mice. To answer this question, we generated a tamoxifen-inducible deletion mutant of Hsp90α and found that conditional deletion of Hsp90α in adult mice caused even more severe apoptosis in germ cells beyond the pachytene stage, leading to complete arrest of spermatogenesis and testicular atrophy. Importantly, immunohistochemical analysis revealed that AR expression in WT testis was more evident in spermatogonia than in spermatocytes, whereas its expression was aberrant and ectopic in Hsp90α KO testis, raising the possibility that an AR abnormality in primordial germ cells is involved in spermatogenesis arrest in the Hsp90α KO mice. Our results suggest that the AR, specifically chaperoned by Hsp90α in spermatogonia, is critical for maintenance of established spermatogenesis and for survival of spermatocytes in adult testis, in addition to setting the first wave of spermatogenesis before puberty.
Experimental selection for body size at age modifies early-life history traits and muscle gene expression in adult zebrafish
Authors: Amaral Ian P. G. , Johnston Ian A. 
Published: August 2012

Summary
The short generation time of the zebrafish (Danio rerio) was exploited to investigate the effects of selection for body size at age on early life-history traits and on the transcriptional response to a growth stimulus in skeletal muscle of adult fish. Replicate populations were either unselected (U-lineage) or subjected to four generations of experimental selection for small (S-lineage) or large body size (L-lineage) at 90 days post-fertilization. Body mass was on average 16.3% and 41.0% higher in the L- than the U- and S-lineages respectively. Egg diameter was 6.4% lower with 13% less yolk in the S- compared to the other lineages. Maternal transcripts for igf2r, bmpr1aa, igf1ar, igf2a, igfbp5a, ghra and igfbp3 in 2-4 cell stage embryos were higher in the L- than S-lineage. Larvae from the L-lineage were significantly larger, but survivorship at the end of the first month was similar between lineages. Gene expression was measured in the fast muscle of adult fish fasted for 7d and then re-fed to satiation for 48h. The expression of 11 insulin-like growth factor pathway genes and 12 other nutritionally-responsive genes was similar for the S- and L-lineages as was gut fullness with feeding. Transcript abundance for 4 genes (igf1a, igf2r, igfbp1a and igfbp1b) showed either regulated or constitutive differences between the S- and L-lineages. For example, igf2 receptors transcripts were higher and igbp1a/b transcripts lower in the L- than S-lineages consistent with an effect of selection on insulin-like growth factor signalling.
Cell death and renewal during prey capture and digestion in the carnivorous spongeAsbestopluma hypogea(Porifera: Poecilosclerida)
Authors: Martinand-Mari Camille , Vacelet Jean , Nickel Michael , Wörheide Gert , Mangeat Paul , Baghdiguian Stephen 
Published: August 2012

SummaryThe sponge Asbestopluma hypogea is unusual among sponges due to its peculiar carnivorous feeding habit. During various stages of its nutrition cycle, the sponge is subjected to spectacular morphological modifications. Starved animals are characterized by many elongated filaments which are crucial for the sponge to capture prey. After capture, and during the digestion process, these filaments actively regress before being regenerated during a subsequent period of starvation. Here, we demonstrate that these morphological events repose on a highly dynamic cellular turnover implying a coordinated sequence of programmed cell death (apoptosis and autophagy), cell proliferation and cell migration. A candidate niche for cell renewal by stem cell proliferation and differentiation was identified at the base of the sponge peduncle, characterized by surpassing levels of BrdU/EdU incorporation. Therefore, BrdU/EdU positive-cells of the peduncle base are candidate motile cells responsible for the regeneration of the prey-capturing main sponge body, i.e. the dynamic filaments. Altogether, our results demonstrate that dynamic of cell renewal in sponge appears to be regulated by cellular mechanisms as multiple and complex as those already identified in bilaterian metazoans.
Selective brain cooling in Arabian oryx (Oryx leucoryx): a physiological mechanism for coping with aridity?
Authors: Hetem Robyn S. , Strauss W. Maartin , Fick Linda G. , Maloney Shane K. , Meyer Leith C. R. , Fuller Andrea , Shobrak Mohammed , Mitchell Duncan 
Published: August 2012

Summary
Selective brain cooling is a thermoregulatory effector proposed to conserve body water and, as such, may help artiodactyls cope with aridity. We measured brain and carotid blood temperature, using implanted data loggers, in five Arabian oryx (Oryx leucoryx) in the desert of Saudi Arabia. On average, brain temperature was 0.24±0.05ºC lower than carotid blood temperature for four oryx in April. Selective brain cooling was enhanced in our Arabian oryx compared to another species from the same genus (gemsbok Oryx gazella gazella), exposed to similar ambient temperatures but less aridity. Arabian oryx displayed a lower threshold (37.8±0.1ºC vs 39.8±0.4ºC), a higher frequency (87±6 % vs 15±15%) and a higher maximum magnitude (1.2±0.2ºC vs 0.5±0.3ºC) of selective brain cooling than did gemsbok. The dominant male oryx displayed less selective brain cooling than did any of the other oryx, but selective brain cooling was enhanced in this oryx as conditions became hotter and drier. Enhanced selective brain cooling in Arabian oryx supports the hypothesis that selective brain cooling would bestow survival advantages for artiodactyl species inhabiting hot hyper-arid environments.
Kinetic Modeling and Optimization of Immobilized Candida antarctica Lipase B Catalysed Synthesis of Butyl-4-Methyl-3-Oxopentanoate using Response Surface Methodology
Authors: Yadav Ganapati D. , Shinde Somnath Dattatray 
Published: August 2012

Abstract
Response surface methodology (RSM) was used to model and optimize the immobilized Candida antarctica lipase B catalysed synthesis of butyl-4-methyl-3-oxopentanoate. To determine optimum conditions of the transesterification, a four-factor and five-level central composite rotatable design (CCRD) was used. The factors studied were enzyme load (A), reaction temperature (B), methyl-4-methyl-3-oxopentanoate concentration (C) and n-butanol concentration (D). A quadratic polynomial regression model was used to analyze the experimental data at a 95% confidence level (p < 0.05). The results indicated that the RSM approach gave reasonable results for the optimization of the reaction parameters in the range of tested parameters. The optimal conditions for the enzymatic reaction were obtained at 0.01 mol of methyl-4-methyl-3-oxopentanoate and 0.03 mol of n-butanol using 104 mg of Novozym 435 at 55 °C and 300 rpm for 6 h. Under these conditions, the transesterification percentage was 87 %. Further, kinetic modelling of the enzymatic synthesis was illustrated. Initial rate data and progress curve data were used to arrive at a suitable model. The kinetics was found to obey the ternary complex ordered bi-bi model with inhibition by the substrate methyl-4-methyl-3-oxopentanoate. The values of kinetic parameters obtained from nonlinear regression analysis were found to be Vmax of 0.04 mol/L.min; Km(A) 0.11 mol/L; Km(B) 2 mol/L and Ki(A) 2.2 mol/L.
Evaluation of Antiulcer Potential of Mimusops hexandra in Experimental Gastro Duodenal Ulcers
Authors: Modi Karuna P. , Lahiri Suman K. , Goswami Sunita S. , Santani Dev D. , Shah Mamta B. 
Published: August 2012

Abstract
The study was aimed to investigate antiulcer effects of acetone extract and its different fractions Mimusops hexandra against experimental gastro-duodenal ulcers. 80% acetone extract of stem bark of Mimusops hexandra (Extract A, p.o.) and its different fractions namely diethyl ether (Extract A1, p.o.), ethyl acetate (Extract A2, p.o.) and aqueous (Extract A3, p.o.) were tested for the presence of preliminary phytoconstituents and were screened for their antiulcer potential in experimental animals using ethanol-HCl and aspirin-induced gastric damage at the dose of 500 mg kg–1p.o. Extract A2 being the most active fraction amongst all the fractions tested was also studied at different doses to find its ED50. Further, to establish the mechanism of action, Extract A2 was also tested for its effects in acetic acid-induced gastric ulcer models and cysteamine-induced duodenal ulcer. The effect was compared with cimetidine. Flavonoids (quercetin), procyanidins, saponins and triterpenoids were found to be present in bark. Oral administration of Extract A2 inhibited formation of gastric lesions induced by aspirin in a dose dependent manner. Elevated level of lipid peroxidation due to ethanol-HCl and aspirin induced gastric damage was significantly (p<0.05) reduced by the treatment with Extract A2. Further, Extract A2 at the dose of 100 mg kg-1 (p.o.) reduced extent of acetic acid induced gastric ulcer in experimental animals. Moreover, protection afforded by Extract A2 against cysteamine-induced duodenal lesions was evident from dose dependent decrease in ulcer index (p<0.05), score for intensity (p<0.05) and total lesion area (p<0.05), when compared with the control group. The antiulcer activity shown by Extract A2 in experimental gastro-duodenal ulcer could be attributed to decrease in gastric acid secretory activity along with strengthening of mucosal defensive mechanisms.
Preparing for Another Round of Swine Flu: Will the WHO's Plan Prove to be a Success for the Global Community and Will the U.S. Lead the Way?
Authors: Maxwell Katie 
Published: August 2012

Abstract
This article seeks to determine whether countries in the global community have governance systems or domestic laws that will enable them to be effective in their preparation and response to influenza pandemics. It begins by analyzing the 2009 H1N1 pandemic, discussing the events leading up to Mexico triggering the IHRs and determining which aspects of Mexico’s pandemic influenza preparedness and response should be used again in the future and which should be retired. It will then take a closer look at how six WHO member states—Australia, Canada, France, Japan, the United Kingdom, and the United States—have or have not integrated lessons learned from the swine flu into their own plans for outbreaks of influenza, evaluating the plans from a comparative perspective in order to determine which plans provide the best guidance for the future.
Whistleblower and Liability Protections for Scientific Laboratory Employees
Authors: Gonzalez Jarod S. , Sutton Victoria 
Published: August 2012

Abstract
The American whistleblower protection scheme as applied to whistleblowers in the laboratory context is a complex patchwork of federal, state, and local laws. Substantial differences in whistleblower protection for laboratory employee whistleblowers depend on a number of factors, including whether the laboratory employee whistleblowers work for public or private institutions and the location of the whistleblower. This document provides a basic summary of the American whistleblower protection scheme applicable to workers employed in laboratories in the United States, with a focus on biological laboratories, and those working with select agents, which are highly infectious agents that warrant special regulations for public safety and national security reasons.
The role of hyperosmotic stress in inflammation and disease
Authors: Brocker Chad , Thompson David C. , Vasiliou Vasilis 
Published: August 2012

AbstractHyperosmotic stress is an often overlooked process that potentially contributes to a number of human diseases. Whereas renal hyperosmolarity is a well-studied phenomenon, recent research provides evidence that many non-renal tissues routinely experience hyperosmotic stress that may contribute significantly to disease initiation and progression. Moreover, a growing body of evidence implicates hyperosmotic stress as a potent inflammatory stimulus by triggering pro-inflammatory cytokine release and inflammation. Under physiological conditions, the urine concentrating mechanism within the inner medullary region of the mammalian kidney exposes cells to high extracellular osmolarity. As such, renal cells have developed many adaptive strategies to compensate for increased osmolarity. Hyperosmotic stress is linked to many maladies, including acute and chronic, as well as local and systemic, inflammatory disorders. Hyperosmolarity triggers cell shrinkage, oxidative stress, protein carbonylation, mitochondrial depolarization, DNA damage, and cell cycle arrest, thus rendering cells susceptible to apoptosis. However, many adaptive mechanisms exist to counter the deleterious effects of hyperosmotic stress, including cytoskeletal rearrangement and up-regulation of antioxidant enzymes, transporters, and heat shock proteins. Osmolyte synthesis is also up-regulated and many of these compounds have been shown to reduce inflammation. The cytoprotective mechanisms and associated regulatory pathways that accompany the renal response to hyperosmolarity are found in many non-renal tissues, suggesting cells are commonly confronted with hyperosmotic conditions. Osmoadaptation allows cells to survive and function under potentially cytotoxic conditions. This review covers the pathological consequences of hyperosmotic stress in relation to disease and emphasizes the importance of considering hyperosmolarity in inflammation and disease progression.