Pub Date : 2009-11-20DOI: 10.2174/1874196700902010137
Anna Gabel, Carsten Lucass, Stefanie M. Zimmer, Christina Bietz, M. Schwenke, R. Wanker
Object permanence tests are a standard procedure to test the cognitive ability to mentally follow a hidden object. To test this capacity in mandrills, we used visible and color-tracking with invisible displacement tests. During visible displacement the object was hidden and moved within its container in full view of the tested individual. During color-tracking with invisible displacement the object was hidden in a colored container, also in full view, but then moved within its container out of view. The tested mandrills were successful in the visible but not in the color-tracking with invisible displacement tests. They did not use the color as a cue for the correct container. One of the animals memorized the position of the container, in which the reward was dropped before the invisible displacement. We assume that the capacity of solving invisible displacement tests has evolved after the evolutionary separation of mandrills and apes.
{"title":"Cognitive Understanding of Object Permanence in Mandrills (Mandrillus sphinx, L.)","authors":"Anna Gabel, Carsten Lucass, Stefanie M. Zimmer, Christina Bietz, M. Schwenke, R. Wanker","doi":"10.2174/1874196700902010137","DOIUrl":"https://doi.org/10.2174/1874196700902010137","url":null,"abstract":"Object permanence tests are a standard procedure to test the cognitive ability to mentally follow a hidden object. To test this capacity in mandrills, we used visible and color-tracking with invisible displacement tests. During visible displacement the object was hidden and moved within its container in full view of the tested individual. During color-tracking with invisible displacement the object was hidden in a colored container, also in full view, but then moved within its container out of view. The tested mandrills were successful in the visible but not in the color-tracking with invisible displacement tests. They did not use the color as a cue for the correct container. One of the animals memorized the position of the container, in which the reward was dropped before the invisible displacement. We assume that the capacity of solving invisible displacement tests has evolved after the evolutionary separation of mandrills and apes.","PeriodicalId":22949,"journal":{"name":"The Open Biology Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75399785","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 : 2009-10-20DOI: 10.2174/1874196700902010114
L. Munaron
Angiogenic factors, including bFGF and VEGF, induce cytosolic calcium (Cac) increases in endothelial cells, critically involved in angiogenesis progression. At low agonist concentrations, Cac elevation is mainly due to calcium entry controlled by a complex interplay between two intracellular messengers, arachidonic acid (AA) and nitric oxide (NO), released upon stimulation with proangiogenic factors: they trigger spatially localized calcium signals restricted to the cell periphery, and such a spatiotemporal pattern could contribute to the specificity of cellular responses. Based on experimental measurements, here we provide the first quantitative spatiotemporal 3D modeling of proangiogenic calcium events in endothelial cells using Virtual Cell framework. The main aims were to validate previously proposed signaling pathways and to suggest new experimental protocols. The most relevant conclusions are: 1. The interplay between AA and NO, previously proposed to be responsible for VEGF/bFGF-dependent calcium entry in endothelial cells, triggers peripheral calcium signals that reproduce the experimental measurements; 2. Spatial restriction is not an artefact due to the calcium-sensitive dye; 3. Channels clusterization in thin lamellipodia plays a key role in the generation of the peripheral-restricted proangiogenic calcium signals; 4. A model containing two distinct channels, named AAAC and NOAC, respectively activated by AA or NO, explains the basic properties of proangiogenic calcium signals. This could be considered an 'open model' containing the simplest conditions leading to a satisfactory reproduction of the experimental results: it should be implemented in order to make it more complete and to maximize physical and biochemical constraints.
{"title":"A Tridimensional Model of Proangiogenic Calcium Signals in Endothelial Cells","authors":"L. Munaron","doi":"10.2174/1874196700902010114","DOIUrl":"https://doi.org/10.2174/1874196700902010114","url":null,"abstract":"Angiogenic factors, including bFGF and VEGF, induce cytosolic calcium (Cac) increases in endothelial cells, critically involved in angiogenesis progression. At low agonist concentrations, Cac elevation is mainly due to calcium entry controlled by a complex interplay between two intracellular messengers, arachidonic acid (AA) and nitric oxide (NO), released upon stimulation with proangiogenic factors: they trigger spatially localized calcium signals restricted to the cell periphery, and such a spatiotemporal pattern could contribute to the specificity of cellular responses. Based on experimental measurements, here we provide the first quantitative spatiotemporal 3D modeling of proangiogenic calcium events in endothelial cells using Virtual Cell framework. The main aims were to validate previously proposed signaling pathways and to suggest new experimental protocols. The most relevant conclusions are: 1. The interplay between AA and NO, previously proposed to be responsible for VEGF/bFGF-dependent calcium entry in endothelial cells, triggers peripheral calcium signals that reproduce the experimental measurements; 2. Spatial restriction is not an artefact due to the calcium-sensitive dye; 3. Channels clusterization in thin lamellipodia plays a key role in the generation of the peripheral-restricted proangiogenic calcium signals; 4. A model containing two distinct channels, named AAAC and NOAC, respectively activated by AA or NO, explains the basic properties of proangiogenic calcium signals. This could be considered an 'open model' containing the simplest conditions leading to a satisfactory reproduction of the experimental results: it should be implemented in order to make it more complete and to maximize physical and biochemical constraints.","PeriodicalId":22949,"journal":{"name":"The Open Biology Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73102961","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 : 2009-10-20DOI: 10.2174/1874196700902010130
C. Schulz, Elisabeth Heiss, F. Gaertner, M. Orban, M. Bruehl, P. Schramm, S. Massberg
Various models exist for the study of platelet and leukocyte function under flow conditions. Flow chambers offer the unique possibility to analyze cell-cell and cell-surface interactions at a great variety of conditions. However, working with small animals (i.e. mice) strongly limits the amount of isolated cells available for perfusion. Here, we present a flow chamber technique based on a small volume multichannel perfusion chamber. First, we studied the interaction of isolated murine platelets with diverse matrix proteins under flow in parallel perfusion experiments using epifluorescence microscopy. In addition, we evaluated real-time processes of platelet-leukocyte interaction and thrombus formation on an inflamed endothelial surface using two-photon microscopy (2PM). We show for the first time that high- speed 2PM allows the visualization of cell-surface-interactions at shear conditions typically found in precapillary vasculature. In summary, the flow chamber model introduced here represents a promising tool for the characterization of cell interactions in vascular research, especially when only small amounts of blood cells are available.
{"title":"Novel Methods for Assessment of Platelet and Leukocyte Function Under Flow - Application of Epifluorescence and Two-Photon Microscopy in a Small Volume Flow Chamber Model","authors":"C. Schulz, Elisabeth Heiss, F. Gaertner, M. Orban, M. Bruehl, P. Schramm, S. Massberg","doi":"10.2174/1874196700902010130","DOIUrl":"https://doi.org/10.2174/1874196700902010130","url":null,"abstract":"Various models exist for the study of platelet and leukocyte function under flow conditions. Flow chambers offer the unique possibility to analyze cell-cell and cell-surface interactions at a great variety of conditions. However, working with small animals (i.e. mice) strongly limits the amount of isolated cells available for perfusion. Here, we present a flow chamber technique based on a small volume multichannel perfusion chamber. First, we studied the interaction of isolated murine platelets with diverse matrix proteins under flow in parallel perfusion experiments using epifluorescence microscopy. In addition, we evaluated real-time processes of platelet-leukocyte interaction and thrombus formation on an inflamed endothelial surface using two-photon microscopy (2PM). We show for the first time that high- speed 2PM allows the visualization of cell-surface-interactions at shear conditions typically found in precapillary vasculature. In summary, the flow chamber model introduced here represents a promising tool for the characterization of cell interactions in vascular research, especially when only small amounts of blood cells are available.","PeriodicalId":22949,"journal":{"name":"The Open Biology Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86499687","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 : 2009-09-10DOI: 10.2174/1874196700902010101
M. Pérez-Villafaña, A. Valiente‐Banuet
Effectiveness of seed dispersal by different species that feed on the fruits of Myrtillocactus geometrizans was evaluated, considering both quantity and quality of dispersal, in a patch of tropical deciduous forest in Zapotitlan de las Salinas. Effectiveness was estimated to be strongly influenced by the post-foraging movements of the frugivores, leading us to suggest that the quality component of seed dispersal occupies a central role in the assessment of disperser effectiveness and to expect that dispersers that stay in the tropical deciduous forest patch after foraging would have highest effectiveness. Birds were the principal dispersers of M. geometrizans. This was particularly true of Phainopepla nitens, since this species showed a high fidelity within the tropical deciduous forest. These observations emphasize that it is important to determine the post-foraging habits of seed dispersers that may move across vegetation patches over the landscape in order to obtain a complete assessment of their role in Neotropical environments.
以萨波提特兰(Zapotitlan de las Salinas)热带落叶林为研究对象，评价了以桃金娘果实为食的不同物种对桃金娘种子的传播效果。研究结果表明，种子传播的质量是影响种子传播有效性的重要因素，因此，种子传播的质量是影响种子传播有效性的重要因素，而种子传播后停留在热带落叶林中的种子传播器的种子传播效率最高。鸟类是其主要的散布者。这种情况在Phainopepla nitens中尤其如此，因为这个物种在热带落叶林中表现出很高的保真度。这些观察结果强调，为了全面评估种子传播者在新热带环境中的作用，确定种子传播者觅食后的习性非常重要。种子传播者可能会在景观上的植被斑块上移动。
{"title":"Effectiveness of dispersal of an ornithocorous cactus Myrtillocactus geometrizans (Cactaceae) in a patchy environment.","authors":"M. Pérez-Villafaña, A. Valiente‐Banuet","doi":"10.2174/1874196700902010101","DOIUrl":"https://doi.org/10.2174/1874196700902010101","url":null,"abstract":"Effectiveness of seed dispersal by different species that feed on the fruits of Myrtillocactus geometrizans was evaluated, considering both quantity and quality of dispersal, in a patch of tropical deciduous forest in Zapotitlan de las Salinas. Effectiveness was estimated to be strongly influenced by the post-foraging movements of the frugivores, leading us to suggest that the quality component of seed dispersal occupies a central role in the assessment of disperser effectiveness and to expect that dispersers that stay in the tropical deciduous forest patch after foraging would have highest effectiveness. Birds were the principal dispersers of M. geometrizans. This was particularly true of Phainopepla nitens, since this species showed a high fidelity within the tropical deciduous forest. These observations emphasize that it is important to determine the post-foraging habits of seed dispersers that may move across vegetation patches over the landscape in order to obtain a complete assessment of their role in Neotropical environments.","PeriodicalId":22949,"journal":{"name":"The Open Biology Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73719391","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 : 2009-08-31DOI: 10.2174/1874196700902010091
R. Rosa, M. Rubert, M. Caetano-Filho, L. Giuliano-Caetano
Specimens of Arapaima gigas from Jamari River (RO) were cytogenetically analyzed. A diploid number of 2n=56 chromosomes was found (28m-sm + 28st-a). Secondary constrictions were observed on the short arms of chromosome 3. Nucleolar Organizer Regions (NORs) were detected at the subterminal region on short arms of the third chromosomal pair by both silver nitrate staining and FISH with 45S rDNA probe, being equivalent to secondary constrictions. The ribosomal sites were also characterized by size heteromorphism and presence of CMA3 + /DAPI - blocks. The constitutive heterochromatin was located at pericentromeric region of some chromosomes. After sequential C- banding and base-specific fluorochromes staining, most of the heterochromatins proved to be neutral, i.e., with similar amounts of AT and GC bases. Nonetheless, some heterochromatic regions were marked by GC-specific fluorochromes in one chromosomal pair and by AT-specific fluorochrome staining on two pairs. The present data are in agreement with previous reports in populations from Araguaya River, indicating that conserved cytogenetic features are present in this important fish species.
{"title":"Conserved Cytogenetic Features in the Amazonian Arapaima, Arapaima gigas (Schinz 1822) from Jamari River, Rondônia-Brazil","authors":"R. Rosa, M. Rubert, M. Caetano-Filho, L. Giuliano-Caetano","doi":"10.2174/1874196700902010091","DOIUrl":"https://doi.org/10.2174/1874196700902010091","url":null,"abstract":"Specimens of Arapaima gigas from Jamari River (RO) were cytogenetically analyzed. A diploid number of 2n=56 chromosomes was found (28m-sm + 28st-a). Secondary constrictions were observed on the short arms of chromosome 3. Nucleolar Organizer Regions (NORs) were detected at the subterminal region on short arms of the third chromosomal pair by both silver nitrate staining and FISH with 45S rDNA probe, being equivalent to secondary constrictions. The ribosomal sites were also characterized by size heteromorphism and presence of CMA3 + /DAPI - blocks. The constitutive heterochromatin was located at pericentromeric region of some chromosomes. After sequential C- banding and base-specific fluorochromes staining, most of the heterochromatins proved to be neutral, i.e., with similar amounts of AT and GC bases. Nonetheless, some heterochromatic regions were marked by GC-specific fluorochromes in one chromosomal pair and by AT-specific fluorochrome staining on two pairs. The present data are in agreement with previous reports in populations from Araguaya River, indicating that conserved cytogenetic features are present in this important fish species.","PeriodicalId":22949,"journal":{"name":"The Open Biology Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75239708","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 : 2009-08-31DOI: 10.2174/1874196700902010095
J. Yakisich
The length of the cell cycle (TC) is a tight regulated process and is important for proper development and homeostasis. Although several methods are available for estimating the duration of the cell cycle, it is difficult to determinate small differences of TC between two different cell populations due to biological and/or experimental variability. A novel strategy based in co-cultivation of two cell strains followed by a series of dilution and propagation of the culture will allow the quantification of very small differences in the length of two cell populations at resolution levels not possible at present with current methods. This is achieved by a separation of the endpoint variable measured to compare between two cell populations. The theoretical basis of this approach is discussed in the context of published experimental data and simulation of idealized experiments using virtual strains of different cell cycle length.
{"title":"Theoretical Basis for the Measurement of Small Differences in the Length of the Cell Cycle between Two Cell Populations","authors":"J. Yakisich","doi":"10.2174/1874196700902010095","DOIUrl":"https://doi.org/10.2174/1874196700902010095","url":null,"abstract":"The length of the cell cycle (TC) is a tight regulated process and is important for proper development and homeostasis. Although several methods are available for estimating the duration of the cell cycle, it is difficult to determinate small differences of TC between two different cell populations due to biological and/or experimental variability. A novel strategy based in co-cultivation of two cell strains followed by a series of dilution and propagation of the culture will allow the quantification of very small differences in the length of two cell populations at resolution levels not possible at present with current methods. This is achieved by a separation of the endpoint variable measured to compare between two cell populations. The theoretical basis of this approach is discussed in the context of published experimental data and simulation of idealized experiments using virtual strains of different cell cycle length.","PeriodicalId":22949,"journal":{"name":"The Open Biology Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81696806","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}
In most cases, hearing loss is a disorder caused by both genetic and environmental factors. The molecular description of deafness has experienced remarkable progress in the last decade, and it is emerging from the use of contemporary methods of cell and molecular biology. Currently, through the application of clinical and molecular genetics it is possible to identify genes associated with inherited, nonsyndromic deafness, and balance dysfunctions of the human cochlea. This brief review provides insights into nonsyndromic hearing loss, since the identification of the molecular basis for the inner ear function provides the basis for developing rational new approaches to diagnosis, management and treatment of auditory and vestibular disorders.
{"title":"Nonsyndromic Deafness - Molecular Update","authors":"Piatto V.B, Secches L.V., Arroyo M.A.S., Lopes A.C.P., Maniglia J.V.","doi":"10.2174/1874196700902010080","DOIUrl":"https://doi.org/10.2174/1874196700902010080","url":null,"abstract":"In most cases, hearing loss is a disorder caused by both genetic and environmental factors. The molecular description of deafness has experienced remarkable progress in the last decade, and it is emerging from the use of contemporary methods of cell and molecular biology. Currently, through the application of clinical and molecular genetics it is possible to identify genes associated with inherited, nonsyndromic deafness, and balance dysfunctions of the human cochlea. This brief review provides insights into nonsyndromic hearing loss, since the identification of the molecular basis for the inner ear function provides the basis for developing rational new approaches to diagnosis, management and treatment of auditory and vestibular disorders.","PeriodicalId":22949,"journal":{"name":"The Open Biology Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74150907","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 : 2009-07-08DOI: 10.2174/1874196700902010054
Jian Wang, T. Man, K. Wong, P. Rao, H. Leung, R. Guerra, C. Lau
Gene copy number change is an essential characteristic of many types of cancer. However, it is important to distinguish copy number variation (CNV) in the human genome of normal individuals from bona fide abnormal copy number changes of genes specific to cancers. Based on Affymetrix 50K single nucleotide polymorphism (SNP) array data, we identified genome-wide copy number variations among 104 normal subjects from three ethnic groups that were used in the HapMap project. Our analysis revealed 155 CNV regions, of which 37% were gains and 63% were losses. About 21% (30) of the CNV regions are concordant with earlier reports. These 155 CNV regions are located on more than 100 cyto- bands across all 23 chromosomes. The CNVs range from 68bp to 18 Mb in length, with a median length of 86 Kb. Eight CNV regions were selected for validation by quantitative PCR. Analysis of genomic sequences within and adjacent to CNVs suggests that repetitive sequences such as long interspersed nuclear elements (LINEs) and long terminal repeats (LTRs) may play a role in the origin of CNVs by facilitating non-allelic homologous recombination. Thirty-two percent of the CNVs identified in this study are associated with segmental duplications. CNVs were not preferentially enriched in gene-encoding regions. Among the 364 genes that are completely encompassed by these 155 CNVs, genes related to olfactory sensory, chemical stimulus, and other physiological responses are significantly enriched. A statistical analysis of CNVs by ethnic group revealed distinct patterns regarding the CNV location and gain-to-loss ratio. The CNVs reported here will help build a more comprehensive map of genomic variations in the human genome and facilitate the differentia- tion between copy number variation and somatic changes in cancers. The potential roles of certain repeat elements in CNV formation, as corroborated by other studies, shed light on the origin of CNVs and will improve our understanding of the mechanisms of genomic rearrangements in the human genome.
{"title":"Genome-Wide Analysis of Copy Number Variations in Normal Population Identified by SNP Arrays","authors":"Jian Wang, T. Man, K. Wong, P. Rao, H. Leung, R. Guerra, C. Lau","doi":"10.2174/1874196700902010054","DOIUrl":"https://doi.org/10.2174/1874196700902010054","url":null,"abstract":"Gene copy number change is an essential characteristic of many types of cancer. However, it is important to distinguish copy number variation (CNV) in the human genome of normal individuals from bona fide abnormal copy number changes of genes specific to cancers. Based on Affymetrix 50K single nucleotide polymorphism (SNP) array data, we identified genome-wide copy number variations among 104 normal subjects from three ethnic groups that were used in the HapMap project. Our analysis revealed 155 CNV regions, of which 37% were gains and 63% were losses. About 21% (30) of the CNV regions are concordant with earlier reports. These 155 CNV regions are located on more than 100 cyto- bands across all 23 chromosomes. The CNVs range from 68bp to 18 Mb in length, with a median length of 86 Kb. Eight CNV regions were selected for validation by quantitative PCR. Analysis of genomic sequences within and adjacent to CNVs suggests that repetitive sequences such as long interspersed nuclear elements (LINEs) and long terminal repeats (LTRs) may play a role in the origin of CNVs by facilitating non-allelic homologous recombination. Thirty-two percent of the CNVs identified in this study are associated with segmental duplications. CNVs were not preferentially enriched in gene-encoding regions. Among the 364 genes that are completely encompassed by these 155 CNVs, genes related to olfactory sensory, chemical stimulus, and other physiological responses are significantly enriched. A statistical analysis of CNVs by ethnic group revealed distinct patterns regarding the CNV location and gain-to-loss ratio. The CNVs reported here will help build a more comprehensive map of genomic variations in the human genome and facilitate the differentia- tion between copy number variation and somatic changes in cancers. The potential roles of certain repeat elements in CNV formation, as corroborated by other studies, shed light on the origin of CNVs and will improve our understanding of the mechanisms of genomic rearrangements in the human genome.","PeriodicalId":22949,"journal":{"name":"The Open Biology Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79014534","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 : 2009-07-08DOI: 10.2174/1874196700902010066
N. Dahanukar, M. Watve
The question how Darwinian mechanisms lead to the evolution of individually costly cooperative behavior has given rise to a number of hypotheses. However, attempts to build a synthesis where different types of mechanisms coexist and interact at different levels of selections are still scarce. Here we derive simple game theoretical models where the group level conflicts are resolved by group selection while simultaneously within group competition is resolved by kin selection and reciprocity. We show that none of the mechanisms, when alone, is as robust in evolving and maintaining cooperation as a synthesis of all. Furthermore, we show that initially within group conflicts can be overcome only by kin selection and not reciprocity. However, once common, different types of reciprocities can maintain high levels of cooperation even if average relatedness among individuals is lowered, groups become large, and the benefits of cooperation are reduced. Based on the synthesis we also propose a possible route to the evolution of social and eusocial systems.
{"title":"Group Selection and Reciprocity among Kin","authors":"N. Dahanukar, M. Watve","doi":"10.2174/1874196700902010066","DOIUrl":"https://doi.org/10.2174/1874196700902010066","url":null,"abstract":"The question how Darwinian mechanisms lead to the evolution of individually costly cooperative behavior has given rise to a number of hypotheses. However, attempts to build a synthesis where different types of mechanisms coexist and interact at different levels of selections are still scarce. Here we derive simple game theoretical models where the group level conflicts are resolved by group selection while simultaneously within group competition is resolved by kin selection and reciprocity. We show that none of the mechanisms, when alone, is as robust in evolving and maintaining cooperation as a synthesis of all. Furthermore, we show that initially within group conflicts can be overcome only by kin selection and not reciprocity. However, once common, different types of reciprocities can maintain high levels of cooperation even if average relatedness among individuals is lowered, groups become large, and the benefits of cooperation are reduced. Based on the synthesis we also propose a possible route to the evolution of social and eusocial systems.","PeriodicalId":22949,"journal":{"name":"The Open Biology Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79458090","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 : 2009-06-11DOI: 10.2174/1874196700902010042
B. Lim
A small mammal survey was conducted in the Bakhuis Mountains of western Suriname in South America as part of a larger environmental and social impact assessment for a proposed bauxite mining concession. The objectives were to establish a baseline study of species diversity and relative abundance for comparison of seasonality, areas, and habitats to facilitate the identification and monitoring of potential impacts of mining to the environment. There were 83 species of small mammals documented comprising 68 species of bats, 8 species of rats and mice, and 7 species of opossums. The most abundant bat was the Seba's short-tailed bat, Carollia perspicillata Linnaeus, which was recorded at all six study sites. The most abundant non-volant small mammal was the Guianan spiny rat, Proechimys guyannensis E. Geoffroy. Noteworthy discoveries during the survey include the documentation of four species of bats new to the fauna of Suriname (Cyttarops alecto Thomas, smoky sheath-tailed bat; Saccopteryx gymnura Thomas; least two-lined sac-winged bat; Diaemus youngi Jentink; bird-feeding vampire bat; and Lasiurus egregius Peters, greater red bat). There were no obvious differences between the dry and wet season samplings that were attributable directly to climatic conditions. In terms of spatial variation, the relative abundance of bats among the five study sites within the concession area was similar to each other, but significantly different from a sixth study site at a nearby ecotourism operation, which had large numbers of three species (C. perspicillata; Molossus molossus, common free-tailed bat; and Sturnira lilium, little yellow- shouldered bat) that are better adapted to human modified surroundings. This suggests that the recent mining explorations in Bakhuis have had a relatively minor impact on bats and that the otherwise pristine forests within the concession can tolerate low levels of disturbance in proportionally small areas over a short duration. For specific habitats, the xeric forest on plateaus had a reduced subset of species of small mammals that were found in the mesic forest of the surrounding lowland regions, which was acting as a species reservoir for upland areas. Small mammals, in particular bats as primary seed dispersers and flower pollinators, are important components of the ecosystem for the successful reforestation of natural habitats, and factors related to community structure are good indicators of the health of the environment.
{"title":"Environmental assessment at the Bakhuis bauxite concession: small-sized mammal diversity and abundance in the lowland humid forests of Suriname.","authors":"B. Lim","doi":"10.2174/1874196700902010042","DOIUrl":"https://doi.org/10.2174/1874196700902010042","url":null,"abstract":"A small mammal survey was conducted in the Bakhuis Mountains of western Suriname in South America as part of a larger environmental and social impact assessment for a proposed bauxite mining concession. The objectives were to establish a baseline study of species diversity and relative abundance for comparison of seasonality, areas, and habitats to facilitate the identification and monitoring of potential impacts of mining to the environment. There were 83 species of small mammals documented comprising 68 species of bats, 8 species of rats and mice, and 7 species of opossums. The most abundant bat was the Seba's short-tailed bat, Carollia perspicillata Linnaeus, which was recorded at all six study sites. The most abundant non-volant small mammal was the Guianan spiny rat, Proechimys guyannensis E. Geoffroy. Noteworthy discoveries during the survey include the documentation of four species of bats new to the fauna of Suriname (Cyttarops alecto Thomas, smoky sheath-tailed bat; Saccopteryx gymnura Thomas; least two-lined sac-winged bat; Diaemus youngi Jentink; bird-feeding vampire bat; and Lasiurus egregius Peters, greater red bat). There were no obvious differences between the dry and wet season samplings that were attributable directly to climatic conditions. In terms of spatial variation, the relative abundance of bats among the five study sites within the concession area was similar to each other, but significantly different from a sixth study site at a nearby ecotourism operation, which had large numbers of three species (C. perspicillata; Molossus molossus, common free-tailed bat; and Sturnira lilium, little yellow- shouldered bat) that are better adapted to human modified surroundings. This suggests that the recent mining explorations in Bakhuis have had a relatively minor impact on bats and that the otherwise pristine forests within the concession can tolerate low levels of disturbance in proportionally small areas over a short duration. For specific habitats, the xeric forest on plateaus had a reduced subset of species of small mammals that were found in the mesic forest of the surrounding lowland regions, which was acting as a species reservoir for upland areas. Small mammals, in particular bats as primary seed dispersers and flower pollinators, are important components of the ecosystem for the successful reforestation of natural habitats, and factors related to community structure are good indicators of the health of the environment.","PeriodicalId":22949,"journal":{"name":"The Open Biology Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75464561","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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