Pub Date : 2010-03-01DOI: 10.1093/BIOHORIZONS/HZQ011
S. Towner
Research concerning animal cognition explores the abilities and capacity of animals to perceive, think and conceive. As an extension of this, researchers have tried to ascertain the concept of animal minds. The field has been a matter of great debate as it has brought into question the uniqueness of the human mind. This dissertation will review the various areas of research that have contributed to our understanding of animal minds, with a specific focus on non-human primates. The term ‘theory of mind’ was originally proposed by Premack and Woodruff in 1978. The ability entails a recognition and understanding of another’s mental states. Recently, this term has included the cognition of seeing. Throughout this article, the important distinction between theory of mind capabilities and complex behavioural analysis is emphasized. It is important to consider how various primates represent entities in their environment, including their own image. In particular reference to this latter point, self-recognition could act as a first step towards understanding others. With this ability, other individuals may then be understood and manipulated through deception, imitation and teaching. In addition to deception, pretend play and external representation are proposed as another dimension of understanding false representations. Decisions about the evolutionary point at which theory of mind may have developed will depend on interpretations of the evidence for these abilities in non-human primates and whether indeed theory of mind is underlying them. Since the conception of the term ‘theory of mind’, the issue may have evolved beyond whether or not there is theory of mind in non-human primates to a more sophisticated appreciation that the concept of mind has many facets and some of these may exist in non-human primates while others may not.
{"title":"Concept of mind in non-human primates","authors":"S. Towner","doi":"10.1093/BIOHORIZONS/HZQ011","DOIUrl":"https://doi.org/10.1093/BIOHORIZONS/HZQ011","url":null,"abstract":"Research concerning animal cognition explores the abilities and capacity of animals to perceive, think and conceive. As an extension of this, researchers have tried to ascertain the concept of animal minds. The field has been a matter of great debate as it has brought into question the uniqueness of the human mind. This dissertation will review the various areas of research that have contributed to our understanding of animal minds, with a specific focus on non-human primates. The term ‘theory of mind’ was originally proposed by Premack and Woodruff in 1978. The ability entails a recognition and understanding of another’s mental states. Recently, this term has included the cognition of seeing. Throughout this article, the important distinction between theory of mind capabilities and complex behavioural analysis is emphasized. It is important to consider how various primates represent entities in their environment, including their own image. In particular reference to this latter point, self-recognition could act as a first step towards understanding others. With this ability, other individuals may then be understood and manipulated through deception, imitation and teaching. In addition to deception, pretend play and external representation are proposed as another dimension of understanding false representations. Decisions about the evolutionary point at which theory of mind may have developed will depend on interpretations of the evidence for these abilities in non-human primates and whether indeed theory of mind is underlying them. Since the conception of the term ‘theory of mind’, the issue may have evolved beyond whether or not there is theory of mind in non-human primates to a more sophisticated appreciation that the concept of mind has many facets and some of these may exist in non-human primates while others may not.","PeriodicalId":52095,"journal":{"name":"Bioscience Horizons","volume":"3 1","pages":"96-104"},"PeriodicalIF":0.0,"publicationDate":"2010-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/BIOHORIZONS/HZQ011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60764367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-03-01DOI: 10.1093/BIOHORIZONS/HZQ010
C. Wardlaw
This study explores the role of the phosphatase Pp2A in regulation of anaphase onset in human cells. During the mitotic cell cycle, cells replicate their DNA in S-phase giving sister chromatids. These chromatids remain tethered together by the cohesin ring until anaphase. The onset of anaphase is triggered by the activation of separase, a protease which cleaves the cohesin ring structure, thereby allowing the sister chromatids to be pulled to opposite ends of the spindle. Prior to anaphase, separase is held in check by one of two inhibitors, namely securin or cyclin B1. Recently, it has been shown that securin-bound separase also binds the protein phosphatase, Pp2A. Importantly, the binding of Pp2A is regulated by separase autocleavage; upon activation, separase autocleaves and releases Pp2A. Strikingly, expression of a non-cleavable separase induces premature sister chromatid separation. Here, we show that the ability of non-cleavable separase to prematurely induce chromatid disjunction requires its catalytic activity. These data lend weight to a handover model whereby separase is initially inhibited by securin; then as securin is degraded, separase autocleaves, Pp2A is released thereby allowing cyclin B1 binding; this in turn maintains separase inhibition until cyclin B1 is degraded. One exciting extension of this model is that the release of Pp2A provides a burst of phosphatase activity just prior to chromatid separation, perhaps to ‘forewarn’ the cell that anaphase onset is imminent. For example, Pp2A activation may ensure that kinetochore–microtubule interactions are stabilized to ensure that all the chromatids are locked onto their K-fibres at the point when sister chromatid cohesion is lost. This study has important implications in understanding how defects in separase regulation can lead to aneuploidy and diseases such as cancer.
{"title":"Protein phosphatase 2A contributes to separase regulation and the co-ordination of anaphase","authors":"C. Wardlaw","doi":"10.1093/BIOHORIZONS/HZQ010","DOIUrl":"https://doi.org/10.1093/BIOHORIZONS/HZQ010","url":null,"abstract":"This study explores the role of the phosphatase Pp2A in regulation of anaphase onset in human cells. During the mitotic cell cycle, cells replicate their DNA in S-phase giving sister chromatids. These chromatids remain tethered together by the cohesin ring until anaphase. The onset of anaphase is triggered by the activation of separase, a protease which cleaves the cohesin ring structure, thereby allowing the sister chromatids to be pulled to opposite ends of the spindle. Prior to anaphase, separase is held in check by one of two inhibitors, namely securin or cyclin B1. Recently, it has been shown that securin-bound separase also binds the protein phosphatase, Pp2A. Importantly, the binding of Pp2A is regulated by separase autocleavage; upon activation, separase autocleaves and releases Pp2A. Strikingly, expression of a non-cleavable separase induces premature sister chromatid separation. Here, we show that the ability of non-cleavable separase to prematurely induce chromatid disjunction requires its catalytic activity. These data lend weight to a handover model whereby separase is initially inhibited by securin; then as securin is degraded, separase autocleaves, Pp2A is released thereby allowing cyclin B1 binding; this in turn maintains separase inhibition until cyclin B1 is degraded. One exciting extension of this model is that the release of Pp2A provides a burst of phosphatase activity just prior to chromatid separation, perhaps to ‘forewarn’ the cell that anaphase onset is imminent. For example, Pp2A activation may ensure that kinetochore–microtubule interactions are stabilized to ensure that all the chromatids are locked onto their K-fibres at the point when sister chromatid cohesion is lost. This study has important implications in understanding how defects in separase regulation can lead to aneuploidy and diseases such as cancer.","PeriodicalId":52095,"journal":{"name":"Bioscience Horizons","volume":"3 1","pages":"66-76"},"PeriodicalIF":0.0,"publicationDate":"2010-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/BIOHORIZONS/HZQ010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60764328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-03-01DOI: 10.1093/BIOHORIZONS/HZQ007
A. Dąbrowska
Stress response signalling pathways are understood only partially in plants. This investigation provides information on a putative membrane-localized receptor that can be added to the collection of high-light (HL) stress–response-mediating proteins. Differences in the expression of a range of antioxidant genes in wild-type Arabidopsis thaliana and a null mutant in At4g21570.1 gene were evaluated using quantitative real-time polymerase chain reaction. It has been found that At4g21570.1 has an effect on the expression of a number of HL-responsive genes encoding ascorbate peroxidase 2, early light-induced protein 1 (ELIP1), type II peroxiredoxin F and two types of glutathione-S-transferases. Due to the fact that some of these genes were reported to be influenced by abscisic acid (ABA), presented results suggest that the investigated putative seven-transmembrane protein (7TMP) may be the missing link between ABA and G-protein a-subunit in plants. However, further study is needed in order to exclude the involvement of other factors, such as hydrogen peroxide, the accumulation of which in a mutant could also contribute to these changes.
{"title":"A novel seven-transmembrane protein may be a receptor involved in high-light stress signalling and response in Arabidopsis","authors":"A. Dąbrowska","doi":"10.1093/BIOHORIZONS/HZQ007","DOIUrl":"https://doi.org/10.1093/BIOHORIZONS/HZQ007","url":null,"abstract":"Stress response signalling pathways are understood only partially in plants. This investigation provides information on a putative membrane-localized receptor that can be added to the collection of high-light (HL) stress–response-mediating proteins. Differences in the expression of a range of antioxidant genes in wild-type Arabidopsis thaliana and a null mutant in At4g21570.1 gene were evaluated using quantitative real-time polymerase chain reaction. It has been found that At4g21570.1 has an effect on the expression of a number of HL-responsive genes encoding ascorbate peroxidase 2, early light-induced protein 1 (ELIP1), type II peroxiredoxin F and two types of glutathione-S-transferases. Due to the fact that some of these genes were reported to be influenced by abscisic acid (ABA), presented results suggest that the investigated putative seven-transmembrane protein (7TMP) may be the missing link between ABA and G-protein a-subunit in plants. However, further study is needed in order to exclude the involvement of other factors, such as hydrogen peroxide, the accumulation of which in a mutant could also contribute to these changes.","PeriodicalId":52095,"journal":{"name":"Bioscience Horizons","volume":"3 1","pages":"49-56"},"PeriodicalIF":0.0,"publicationDate":"2010-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/BIOHORIZONS/HZQ007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60764762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-03-01DOI: 10.1093/BIOHORIZONS/HZQ001
L. Milewski
Ageing is one of biology’s longstanding enigmas—a problem that has perplexed both medical gerontologists and evolutionary biologists alike. One of the most prominent theories on the biochemical causes of ageing is the telomere-cell senescence theory. This theory proposes that ageing is due to the build up of telomere-induced senescent cells within the body. From an evolutionary standpoint, this system is thought to have evolved via antagonistic pleiotropy. Under this view, ageing is seen as a side effect of the telomere-cell senescence system, with the primary function of it being to defend against cancer. However, there are a number of problems with interpreting the system in this way, and several lines of evidence suggest that it was selected first and foremost to cause ageing. This logically entails the view that ageing is adaptive—an idea that is currently controversial.
{"title":"The evolution of ageing","authors":"L. Milewski","doi":"10.1093/BIOHORIZONS/HZQ001","DOIUrl":"https://doi.org/10.1093/BIOHORIZONS/HZQ001","url":null,"abstract":"Ageing is one of biology’s longstanding enigmas—a problem that has perplexed both medical gerontologists and evolutionary biologists alike. One of the most prominent theories on the biochemical causes of ageing is the telomere-cell senescence theory. This theory proposes that ageing is due to the build up of telomere-induced senescent cells within the body. From an evolutionary standpoint, this system is thought to have evolved via antagonistic pleiotropy. Under this view, ageing is seen as a side effect of the telomere-cell senescence system, with the primary function of it being to defend against cancer. However, there are a number of problems with interpreting the system in this way, and several lines of evidence suggest that it was selected first and foremost to cause ageing. This logically entails the view that ageing is adaptive—an idea that is currently controversial.","PeriodicalId":52095,"journal":{"name":"Bioscience Horizons","volume":"3 1","pages":"77-84"},"PeriodicalIF":0.0,"publicationDate":"2010-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/BIOHORIZONS/HZQ001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60764600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-03-01DOI: 10.1093/BIOHORIZONS/HZQ006
Alexander Rose
Research article TnAbaR1: a novel Tn7-related transposon in Acinetobacter baumannii that contributes to the accumulation and dissemination of large repertoires of resistance genes
研究文章TnAbaR1:鲍曼不动杆菌中一种新的tn7相关转座子，有助于大量耐药基因的积累和传播
{"title":"TnAbaR1: a novel Tn7-related transposon in Acinetobacter baumannii that contributes to the accumulation and dissemination of large repertoires of resistance genes","authors":"Alexander Rose","doi":"10.1093/BIOHORIZONS/HZQ006","DOIUrl":"https://doi.org/10.1093/BIOHORIZONS/HZQ006","url":null,"abstract":"Research article TnAbaR1: a novel Tn7-related transposon in Acinetobacter baumannii that contributes to the accumulation and dissemination of large repertoires of resistance genes","PeriodicalId":52095,"journal":{"name":"Bioscience Horizons","volume":"25 1","pages":"40-48"},"PeriodicalIF":0.0,"publicationDate":"2010-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/BIOHORIZONS/HZQ006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60764712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-01DOI: 10.1093/BIOHORIZONS/HZP012
L. Bellanca
Collaboration allows researchers to combine the strength of different disciplines to undertake research that neither could do individually. Scientific collaboration can be examined by analysing patterns of co-authorship of papers in publication databases (e.g. Web of Science) using methods from Social Network Analysis. In this project, I describe three networks consisting of researchers in the Biology and Chemistry Departments at the University of York to investigate degree, degree distribution, key brokers and preference of researchers for collaborating within or outside their own research field. Clustering (or transitivity) was used to describe whether collaboration is more likely if two researchers have a collaborator in common. To introduce a control and realize the significance of the results produced, a network consisting of 98 researchers from the Chemistry and Biology departments was produced and compared with a distribution of 1000 ER random graphs for degree, transitivity and betweenness. We find that researchers in the Department of Biology (50 researchers) have fewer collaborations with their departmental colleagues than those in the Department of Chemistry (45 researchers): the average number of links each researcher had with others in the Biology collaboration network was 2.6, the corresponding values for Chemistry were 4.8 links per researcher. We also find that researchers within the Chemistry department were more likely than their colleagues in Biology to collaborate with another researcher if they had a collaborator in common. One aim of the study was to characterize the extent of interdisciplinary research within the Department of Biology. Staff in the Biology department were categorized into distinct research foci, indicating the discipline of the researcher. There were many links from the Bioinformatics and Mathematics, and Biophysics and Biochemistry foci, to other foci, implying that staff within these foci were interdisciplinary in their research—indicative of their role in providing techniques or tools that are applicable across discipline boundaries. This sort of analysis provides quantitative evidence to understand the social patterns of scientific collaboration and may be a useful tool in the development of strategies to promote interdisciplinary research within research institutions.
合作使研究人员能够结合不同学科的力量来进行任何一方都无法单独完成的研究。科学合作可以通过使用社会网络分析方法分析出版数据库(例如Web of Science)中论文的共同作者模式来检查。在这个项目中，我描述了由约克大学生物系和化学系的研究人员组成的三个网络，以调查学位、学位分布、主要经纪人和研究人员在自己的研究领域内外合作的偏好。聚类(或传递性)被用来描述如果两个研究人员有一个共同的合作者，合作是否更有可能。为了引入控制并认识到所产生结果的重要性，由化学和生物系的98名研究人员组成了一个网络，并与1000个ER随机图的分布进行了度、传递性和中间性的比较。我们发现生物系(50名研究人员)的研究人员与其部门同事的合作少于化学系(45名研究人员):每位研究人员在生物合作网络中与其他人的平均链接数为2.6，化学研究人员的相应值为每位研究人员4.8个链接。我们还发现，如果化学系的研究人员有共同的合作者，他们比生物学的同事更有可能与另一名研究人员合作。这项研究的目的之一是描述生物系内跨学科研究的程度。生物系的工作人员被分为不同的研究重点，表明了研究人员的学科。从生物信息学和数学，生物物理学和生物化学的焦点到其他焦点有许多联系，这意味着这些焦点的工作人员在他们的研究中是跨学科的-表明他们在提供适用于跨学科边界的技术或工具方面的作用。这种分析为理解科学合作的社会模式提供了定量证据，并可能成为制定促进研究机构内部跨学科研究的战略的有用工具。
{"title":"Measuring interdisciplinary research: analysis of co-authorship for research staff at the University of York","authors":"L. Bellanca","doi":"10.1093/BIOHORIZONS/HZP012","DOIUrl":"https://doi.org/10.1093/BIOHORIZONS/HZP012","url":null,"abstract":"Collaboration allows researchers to combine the strength of different disciplines to undertake research that neither could do individually. Scientific collaboration can be examined by analysing patterns of co-authorship of papers in publication databases (e.g. Web of Science) using methods from Social Network Analysis. In this project, I describe three networks consisting of researchers in the Biology and Chemistry Departments at the University of York to investigate degree, degree distribution, key brokers and preference of researchers for collaborating within or outside their own research field. Clustering (or transitivity) was used to describe whether collaboration is more likely if two researchers have a collaborator in common. To introduce a control and realize the significance of the results produced, a network consisting of 98 researchers from the Chemistry and Biology departments was produced and compared with a distribution of 1000 ER random graphs for degree, transitivity and betweenness. We find that researchers in the Department of Biology (50 researchers) have fewer collaborations with their departmental colleagues than those in the Department of Chemistry (45 researchers): the average number of links each researcher had with others in the Biology collaboration network was 2.6, the corresponding values for Chemistry were 4.8 links per researcher. We also find that researchers within the Chemistry department were more likely than their colleagues in Biology to collaborate with another researcher if they had a collaborator in common. One aim of the study was to characterize the extent of interdisciplinary research within the Department of Biology. Staff in the Biology department were categorized into distinct research foci, indicating the discipline of the researcher. There were many links from the Bioinformatics and Mathematics, and Biophysics and Biochemistry foci, to other foci, implying that staff within these foci were interdisciplinary in their research—indicative of their role in providing techniques or tools that are applicable across discipline boundaries. This sort of analysis provides quantitative evidence to understand the social patterns of scientific collaboration and may be a useful tool in the development of strategies to promote interdisciplinary research within research institutions.","PeriodicalId":52095,"journal":{"name":"Bioscience Horizons","volume":"2 1","pages":"99-112"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/BIOHORIZONS/HZP012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60763917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-01DOI: 10.1093/BIOHORIZONS/HZP022
I. Ibrahim
In higher plants and green algae, photosynthesis takes place within specialized sub-cellular organelles called chloroplasts. Chloroplasts were once prokaryotes and evolved by endosymbiosis from cyanobacteria. They contain a semi-autonomous genetic system that encodes for core proteins of photosynthetic reaction centres in the energy-transducing membrane known as the chloroplast thylakoid. The photosynthetic apparatus in the thylakoid membrane makes use of excitation energy from sunlight to remove four electrons and protons from two water molecules. The electrons transfer them to the electron acceptor ferredoxin and NADPþ, respectively. In this system, plastoquinone acts as a mobile electron and proton carrier between Photosystem I and Photosystem II in reduction–oxidation or ‘redox’ reactions. A balanced redox state in the chloroplast is important for efficient energy conversion. However, the slightest error could lead to photo-inactivation as well as DNA mutation. Therefore, photosynthetic enzymes that are involved in photosynthesis are tightly regulated. In this study we analyse the mechanism of redox regulation involved in chloroplast gene expression that requires chloroplast sensor kinase (CSK). CSK is a bacterial-like histidine kinase that functions as a two-component system. Such simple but effective signalling transduction is abundant in prokaryotes, but found less widely in eukaryotic cells. CSK is encoded by the nuclear genomes of all higher plants examined, and the CSK proteins are targeted to chloroplasts where they function as a redox sensor. Through the cloning process, the result expressed the full-length CSK and the putative sensor domain (GAF domain) into a pGEX-6P-2 plasmid containing a GST tag. The construction was over-expressed into Escherichia coli cells. From bioinformatics study, it was found that in higher plants CSK is a modified histidine kinase, whereas in diatoms and red algae it is a typical histidine kinase.
{"title":"Characterizing chloroplast sensor kinase","authors":"I. Ibrahim","doi":"10.1093/BIOHORIZONS/HZP022","DOIUrl":"https://doi.org/10.1093/BIOHORIZONS/HZP022","url":null,"abstract":"In higher plants and green algae, photosynthesis takes place within specialized sub-cellular organelles called chloroplasts. Chloroplasts were once prokaryotes and evolved by endosymbiosis from cyanobacteria. They contain a semi-autonomous genetic system that encodes for core proteins of photosynthetic reaction centres in the energy-transducing membrane known as the chloroplast thylakoid. The photosynthetic apparatus in the thylakoid membrane makes use of excitation energy from sunlight to remove four electrons and protons from two water molecules. The electrons transfer them to the electron acceptor ferredoxin and NADPþ, respectively. In this system, plastoquinone acts as a mobile electron and proton carrier between Photosystem I and Photosystem II in reduction–oxidation or ‘redox’ reactions. A balanced redox state in the chloroplast is important for efficient energy conversion. However, the slightest error could lead to photo-inactivation as well as DNA mutation. Therefore, photosynthetic enzymes that are involved in photosynthesis are tightly regulated. In this study we analyse the mechanism of redox regulation involved in chloroplast gene expression that requires chloroplast sensor kinase (CSK). CSK is a bacterial-like histidine kinase that functions as a two-component system. Such simple but effective signalling transduction is abundant in prokaryotes, but found less widely in eukaryotic cells. CSK is encoded by the nuclear genomes of all higher plants examined, and the CSK proteins are targeted to chloroplasts where they function as a redox sensor. Through the cloning process, the result expressed the full-length CSK and the putative sensor domain (GAF domain) into a pGEX-6P-2 plasmid containing a GST tag. The construction was over-expressed into Escherichia coli cells. From bioinformatics study, it was found that in higher plants CSK is a modified histidine kinase, whereas in diatoms and red algae it is a typical histidine kinase.","PeriodicalId":52095,"journal":{"name":"Bioscience Horizons","volume":"2 1","pages":"191-196"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/BIOHORIZONS/HZP022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60764537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-01DOI: 10.1093/BIOHORIZONS/HZP023
L. Wetherill
Non-alcoholic fatty liver disease (NAFLD) is a growing clinical problem, which manifests itself particularly in obese subjects who may have the metabolic syndrome. A two-hit hypothesis for the pathogenesis of the disease has been proposed. The first hit is the development of insulin resistance leading to fat accumulation specifically in the liver. The second hit involves oxidative damage to the liver when intracellular triglyceride is metabolized by beta-oxidation in the mitochondria to produce harmful reactive oxygen species (ROS) and their hydroperoxide by-products. An in vitro model for NAFLD along with a method to detect the levels of oxidative stress would be useful for testing this hypothesis. Such a model would also allow investigation of the ability of antioxidants such as selenium to prevent oxidative damage. This study aimed to develop a method for assessing the levels of oxidative stress in cultured fat-loaded human hepatocytes (C3A cells) and hepatic stellate cells (LX-2 cells) using electron spin resonance with the spin trap 1-hydroxy2,2,6,6-tetramethyl-4-oxopiperidine (TEMPONE-H). Cells were fat-loaded with either LPON (lactate, pyruvate, octanoate and NH4 þ) or oleate. Initial experiments showed that the culture media alone generated free radicals but this was minimal when Dulbecco’s phosphate-buffered saline was used as the TEMPONE-H carrier. It proved difficult to detect the free radical production by cells cultured in the basal state; however, when marked oxidative stress was induced in the cells by adding tertiary butyl hydroperoxide (t-BuOOH), free radical production by cells could be identified. Pre-treating cells with selenium, to induce the synthesis of selenoenzymes with antioxidant action, protected cells from the harmful effects of t-BuOOH. This supported selenium’s role as an antioxidant, which may have the potential to prevent the onset of non-alcoholic steato-hepatitis. The human vascular endothelial cell line EAhy926 also accumulates lipid as triglyceride when pre-treated with oleate but not with LPON. This suggests that the use of LPON rather than oleate may be a more appropriate model of NAFLD.
{"title":"Can ESR be used to assess the levels of oxidative stress in fat-loaded human hepatocytes and hepatic stellate cells?","authors":"L. Wetherill","doi":"10.1093/BIOHORIZONS/HZP023","DOIUrl":"https://doi.org/10.1093/BIOHORIZONS/HZP023","url":null,"abstract":"Non-alcoholic fatty liver disease (NAFLD) is a growing clinical problem, which manifests itself particularly in obese subjects who may have the metabolic syndrome. A two-hit hypothesis for the pathogenesis of the disease has been proposed. The first hit is the development of insulin resistance leading to fat accumulation specifically in the liver. The second hit involves oxidative damage to the liver when intracellular triglyceride is metabolized by beta-oxidation in the mitochondria to produce harmful reactive oxygen species (ROS) and their hydroperoxide by-products. An in vitro model for NAFLD along with a method to detect the levels of oxidative stress would be useful for testing this hypothesis. Such a model would also allow investigation of the ability of antioxidants such as selenium to prevent oxidative damage. This study aimed to develop a method for assessing the levels of oxidative stress in cultured fat-loaded human hepatocytes (C3A cells) and hepatic stellate cells (LX-2 cells) using electron spin resonance with the spin trap 1-hydroxy2,2,6,6-tetramethyl-4-oxopiperidine (TEMPONE-H). Cells were fat-loaded with either LPON (lactate, pyruvate, octanoate and NH4 þ) or oleate. Initial experiments showed that the culture media alone generated free radicals but this was minimal when Dulbecco’s phosphate-buffered saline was used as the TEMPONE-H carrier. It proved difficult to detect the free radical production by cells cultured in the basal state; however, when marked oxidative stress was induced in the cells by adding tertiary butyl hydroperoxide (t-BuOOH), free radical production by cells could be identified. Pre-treating cells with selenium, to induce the synthesis of selenoenzymes with antioxidant action, protected cells from the harmful effects of t-BuOOH. This supported selenium’s role as an antioxidant, which may have the potential to prevent the onset of non-alcoholic steato-hepatitis. The human vascular endothelial cell line EAhy926 also accumulates lipid as triglyceride when pre-treated with oleate but not with LPON. This suggests that the use of LPON rather than oleate may be a more appropriate model of NAFLD.","PeriodicalId":52095,"journal":{"name":"Bioscience Horizons","volume":"96 1","pages":"197-204"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/BIOHORIZONS/HZP023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60764549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-01DOI: 10.1093/BIOHORIZONS/HZP017
Claire Asher
Habitat loss, disturbance and fragmentation are thought to be major threats to many species, particularly those in habitats that are already rare. In this study, we examined whether habitat disturbance, primarily due to the cultivation of coffee, has had a major impact on populations of two species of bats in a Honduran cloud forest, using genetic diversity as a measure of population health. Bats were selected as the study species because they play a major role in seed dispersal within the tropics. I compared the genetic diversity of two frugivorous bat species, Sturnira ludovici and Artibeus toltecus, between two localities within Cusuco National Park; a buffer zone in which some human activity, including coffee plantations, is allowed, and the core zone in which no disturbance is permitted. Genetic diversity was assessed using intersimple sequence repeats, a technique similar to random amplification of polymorphic DNA (RAPD). I also measured various habitat variables including foliage height diversity (FHD), fruit availability, canopy cover, aspect of slope and angle of slope in the two sites. I found that FHD and fruit availability differed significantly between the two localities, with the buffer zone having higher values for both. Despite these differences in habitat, we found no significant differences in the level of genetic diversity between the two locations for either bat species. This may be because effective population sizes of the bats do not differ significantly between the sites, because of a lag between disturbance and population decline or because migration is sufficiently frequent to homogenize allele frequencies between the localities.
{"title":"Patterns of genetic diversity in populations of two bat species (Sturnira ludovici and Artibeus toltecus) in Cusuco National Park, Honduras","authors":"Claire Asher","doi":"10.1093/BIOHORIZONS/HZP017","DOIUrl":"https://doi.org/10.1093/BIOHORIZONS/HZP017","url":null,"abstract":"Habitat loss, disturbance and fragmentation are thought to be major threats to many species, particularly those in habitats that are already rare. In this study, we examined whether habitat disturbance, primarily due to the cultivation of coffee, has had a major impact on populations of two species of bats in a Honduran cloud forest, using genetic diversity as a measure of population health. Bats were selected as the study species because they play a major role in seed dispersal within the tropics. I compared the genetic diversity of two frugivorous bat species, Sturnira ludovici and Artibeus toltecus, between two localities within Cusuco National Park; a buffer zone in which some human activity, including coffee plantations, is allowed, and the core zone in which no disturbance is permitted. Genetic diversity was assessed using intersimple sequence repeats, a technique similar to random amplification of polymorphic DNA (RAPD). I also measured various habitat variables including foliage height diversity (FHD), fruit availability, canopy cover, aspect of slope and angle of slope in the two sites. I found that FHD and fruit availability differed significantly between the two localities, with the buffer zone having higher values for both. Despite these differences in habitat, we found no significant differences in the level of genetic diversity between the two locations for either bat species. This may be because effective population sizes of the bats do not differ significantly between the sites, because of a lag between disturbance and population decline or because migration is sufficiently frequent to homogenize allele frequencies between the localities.","PeriodicalId":52095,"journal":{"name":"Bioscience Horizons","volume":"2 1","pages":"147-154"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/BIOHORIZONS/HZP017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60764052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-01DOI: 10.1093/BIOHORIZONS/HZP013
K. Samani
The main aim of this project was to produce an interactive e-learning resource explaining the pharmacokinetic principles related to therapeutic drug monitoring (TDM). The target audience for the resource were scientists at Manchester Royal Infirmary and the intended learning outcome for the users was to improve their understanding of the pharmacology behind the results they generate. The null hypothesis stated that the resource would not cause a significant improvement in the users' understanding of pharmacokinetics. The ADDIE Instructional Design Model was applied to the learning situation. A pre-project questionnaire allowed for a needs analysis to be conducted, determining the current level of knowledge. Design and development involved production of project plans and story- boards and the entire resource was produced using Opus Professional. The resource was distributed via compact discs, along with pre- and post-resource questionnaires to permit analysis. Knowledge was compared before and after using the resource to establish the effectiveness of the resource, and the functionality of the resource was evaluated. The needs questionnaire results outlined the exist- ing level of knowledge as being varied and provided suggestions for possible concepts to include in the resource. A more precise and accurate definition of TDM, why it is carried out, and the pharmacokinetic parameters were apparent in the post-resource questionnaire results. Confidence in the understanding and interpretation of data produce was not significantly improved (Wilcoxon matched pairs signed ranks test, n ¼ 14, P ¼ 0.13), while confidence in the understanding of pharmacokinetic parameters was significantly improved (Wilcoxon matched pairs signed ranks test, n ¼ 16, P ¼ 0.01). About 81% of the audience found the resource very helpful to understand- ing TDM and all of the users found it either easy to use or very easy to use. The post-resource results showed that confidence in the understanding of pharmacokinetics was improved, indicating that the learning outcomes of the user were achieved thus allowing the null hypothesis to be rejected. However, confidence in understanding the data generated was not improved, suggesting a possible aspect to be developed if the project was to be repeated. Functionality of the resource was successful as users found the resource easy to use and navigate.
{"title":"Therapeutic drug monitoring: an e-learning resource","authors":"K. Samani","doi":"10.1093/BIOHORIZONS/HZP013","DOIUrl":"https://doi.org/10.1093/BIOHORIZONS/HZP013","url":null,"abstract":"The main aim of this project was to produce an interactive e-learning resource explaining the pharmacokinetic principles related to therapeutic drug monitoring (TDM). The target audience for the resource were scientists at Manchester Royal Infirmary and the intended learning outcome for the users was to improve their understanding of the pharmacology behind the results they generate. The null hypothesis stated that the resource would not cause a significant improvement in the users' understanding of pharmacokinetics. The ADDIE Instructional Design Model was applied to the learning situation. A pre-project questionnaire allowed for a needs analysis to be conducted, determining the current level of knowledge. Design and development involved production of project plans and story- boards and the entire resource was produced using Opus Professional. The resource was distributed via compact discs, along with pre- and post-resource questionnaires to permit analysis. Knowledge was compared before and after using the resource to establish the effectiveness of the resource, and the functionality of the resource was evaluated. The needs questionnaire results outlined the exist- ing level of knowledge as being varied and provided suggestions for possible concepts to include in the resource. A more precise and accurate definition of TDM, why it is carried out, and the pharmacokinetic parameters were apparent in the post-resource questionnaire results. Confidence in the understanding and interpretation of data produce was not significantly improved (Wilcoxon matched pairs signed ranks test, n ¼ 14, P ¼ 0.13), while confidence in the understanding of pharmacokinetic parameters was significantly improved (Wilcoxon matched pairs signed ranks test, n ¼ 16, P ¼ 0.01). About 81% of the audience found the resource very helpful to understand- ing TDM and all of the users found it either easy to use or very easy to use. The post-resource results showed that confidence in the understanding of pharmacokinetics was improved, indicating that the learning outcomes of the user were achieved thus allowing the null hypothesis to be rejected. However, confidence in understanding the data generated was not improved, suggesting a possible aspect to be developed if the project was to be repeated. Functionality of the resource was successful as users found the resource easy to use and navigate.","PeriodicalId":52095,"journal":{"name":"Bioscience Horizons","volume":"2 1","pages":"113-124"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/BIOHORIZONS/HZP013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60763955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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