In nature, essential resources for organisms, such as food for animals and light, water and nutrients for plants, are usually heterogeneously distributed, even at very small scale. As a result, all organisms, particul...In nature, essential resources for organisms, such as food for animals and light, water and nutrients for plants, are usually heterogeneously distributed, even at very small scale. As a result, all organisms, particularly plants mostly sessile, have a difficulty in acquiring essential resources from their environments. Animals express various types of foraging behavior to capture heterogeneously distributed essential foods. Clonal growth ( a vegetative reproductive process where by more than one individual of identical genetic composition is formed ) provides clonal plant not only with many “mouths” at different spatial positions, but also with a large spacial movability. As a clonal plant grows in environments characterized by a small scale resource heterogeneity, its inter ramet connection permits a resource sharing among the connected ramets. In addition, it may also allow certain ramets to respond locally and non locally to resousce heterogeneity. This may lead to a division of labor among the connected ramets and a selective placement of ramets in favorable micro habitats. Together these may enhance exploitation of resource heterogeneity by clonal plants, and in turn greatly contribute to maintenance or improvement of fitness. Such a behavior of clonal plants, expressed in heterogeneous environments, is to a large extent comparable to that of animals. Therefore, it has been considered as foraging behavior in clonal plants. More recently, it has been observed that phenotypic plasticity of clonal plants, which is relevant to foraging behavior, varies among species, types of genet architecture as well as among types of plants’ habitats. Foraging in clonal plants and its diversity have been receiving increasingly intensive investigations.展开更多
Aims Soil heterogeneity is common in natural habitats.It may trigger for-aging responses(placing more ramets and/or roots in nutrient-rich patches than in nutrient-poor patches)and further affect the growth of plants....Aims Soil heterogeneity is common in natural habitats.It may trigger for-aging responses(placing more ramets and/or roots in nutrient-rich patches than in nutrient-poor patches)and further affect the growth of plants.However,the impact of soil heterogeneity on competitive interactions has been little tested.Methods We conducted a greenhouse experiment to investigate the effects of soil heterogeneity on intraspecific competition with a stolonif-erous herb Hydrocotyle vulgaris.We grew one(without com-petition)or nine ramets(with competition)of H.vulgaris under a homogeneous environment and two heterogeneous environ-ments differing in patch size(large or small patches).In the het-erogeneous treatment,the soil consisted of the same number of nutrient-rich and nutrient-poor patches arranged in a chessboard manner,and in the homogeneous treatment,the soil was an even mixture of the same amount of the nutrient-rich and the nutrient-poor soil.Important Findings Irrespective of intraspecific competition,H.vulgaris showed for-aging responses to soil heterogeneity in the large patch treatment,e.g.it produced significantly more biomass,ramets,aboveground mass and root mass in the nutrient-rich patches than in the nutrient-poor patches.In the small patch treatment,foraging responses were observed when intraspecific competition was present,but responses were not observed when there was no competition.However,we find a significant effect of soil heterogeneity on neither overall growth nor competitive intensity of H.vulgaris.Our results suggest that foraging responses to soil heterogeneity may not necessarily be adaptive and intraspecific competition may not be influenced by soil heterogeneity.展开更多
Intratumoral heterogeneity including genetic and nongenetic mechanisms refers to biological differences amongst malignant cells originated within the same tumor.Both,cell differentiation hierarchy and stochasticity in...Intratumoral heterogeneity including genetic and nongenetic mechanisms refers to biological differences amongst malignant cells originated within the same tumor.Both,cell differentiation hierarchy and stochasticity in gene expression and signaling pathways may result in phenotypic differences of cancer cells.Since a tumor consists of cancer cell clones that display distinct behaviours,changes in clonal proliferative behavior may also contribute to the phenotypic variability of tumor cells.There is a need to reveal molecular actions driving chemotherapeutic resistance in colon cancer cells.In general,it is widely hypothesized that therapeutic resistance in colorectal cancer is a consequence of the preferential survival of cancer stem cells.However,recent data regarding colorectal cancer suggest that resistance to anticancer therapy and post-therapeutic tumor reappearence could be related to variations of clonal dynamics.Understanding the interaction of genetic and nongenetic determinants influencing the functional diversity and therapy response of tumors should be a future direction for cancer research.展开更多
Based on studies over the last several decades,the self-renewing skeletal lineages derived from bone marrow stroma could be an ideal source for skeletal tissue engineering.However,the markers for osteogenic precursors...Based on studies over the last several decades,the self-renewing skeletal lineages derived from bone marrow stroma could be an ideal source for skeletal tissue engineering.However,the markers for osteogenic precursors;i.e.,bone marrow-derived skeletal stem cells(SSCs),in association with other cells of the marrow stroma(bone marrow stromal cells,BMSCs)and their heterogeneous nature both in vivo and in vitro remain to be clarified.This review aims to highlight:i)the importance of distinguishing BMSCs/SSCs from other“mesenchymal stem/stromal cells”,and ii)factors that are responsible for their heterogeneity,and how these factors impact on the differentiation potential of SSCs towards bone.The prospective role of SSC enrichment,their expansion and its impact on SSC phenotype is explored.Emphasis has also been given to emerging single cell RNA sequencing approaches in scrutinizing the unique population of SSCs within the BMSC population,along with their committed progeny.Understanding the factors involved in heterogeneity may help researchers to improvise their strategies to isolate,characterize and adopt best culture practices and source identification to develop standard operating protocols for developing reproducible stem cells grafts.However,more scientific understanding of the molecular basis of heterogeneity is warranted that may be obtained from the robust high-throughput functional transcriptomics of single cells or clonal populations.展开更多
Aims Plants can benefit from heterogeneous environments via disproportionately increasing resource harvesting in resource-rich patches.Their initial growing positions with respect to resource patches may thus have imp...Aims Plants can benefit from heterogeneous environments via disproportionately increasing resource harvesting in resource-rich patches.Their initial growing positions with respect to resource patches may thus have important influences on their performance and relative competitive ability.Such impacts may differ between species with contrasting spatial architectures.However,the potential influence of initial growing positions in heterogeneous environment on plant growth and competition has largely been ignored.Methods We grew the phalanx plant Carex neurocarpa and the guerrilla plant Bolboschoenus planiculmis alone or in competition in a heterogeneous environment consisting of high-and low-nutrient soil patches.In treatments without competition,one ramet of each species was grown in either a high-or a low-nutrient patch in the heterogeneous environment.In treatments with competition,a ramet of the target species was grown in either a high-or a low-nutrient patch,and a ramet of the competitor species was grown in the same patch as the target species or an adjacent patch with a different nutrient level.Important Findings Without competition C.neurocarpa produced more biomass and ramets when initially grown in a high-nutrient patch than when initially grown in a low-nutrient patch.With competition,these differences disappeared.Consequently,competitive intensity on C.neurocarpa was higher when it initially grew in a high-nutrient patch than when it initially grew in a low-nutrient patch.These impacts were independent of the initial position of its competitor.By contrast,the initial positions of B.planiculmis did not influence its growth or competitive response.Therefore,in heterogeneous environments,initial growing positions of clonal plants may influence their performance in competition-free environments and may also affect their relative competitive ability,and these effects may depend on spatial architecture of the plants.展开更多
文摘In nature, essential resources for organisms, such as food for animals and light, water and nutrients for plants, are usually heterogeneously distributed, even at very small scale. As a result, all organisms, particularly plants mostly sessile, have a difficulty in acquiring essential resources from their environments. Animals express various types of foraging behavior to capture heterogeneously distributed essential foods. Clonal growth ( a vegetative reproductive process where by more than one individual of identical genetic composition is formed ) provides clonal plant not only with many “mouths” at different spatial positions, but also with a large spacial movability. As a clonal plant grows in environments characterized by a small scale resource heterogeneity, its inter ramet connection permits a resource sharing among the connected ramets. In addition, it may also allow certain ramets to respond locally and non locally to resousce heterogeneity. This may lead to a division of labor among the connected ramets and a selective placement of ramets in favorable micro habitats. Together these may enhance exploitation of resource heterogeneity by clonal plants, and in turn greatly contribute to maintenance or improvement of fitness. Such a behavior of clonal plants, expressed in heterogeneous environments, is to a large extent comparable to that of animals. Therefore, it has been considered as foraging behavior in clonal plants. More recently, it has been observed that phenotypic plasticity of clonal plants, which is relevant to foraging behavior, varies among species, types of genet architecture as well as among types of plants’ habitats. Foraging in clonal plants and its diversity have been receiving increasingly intensive investigations.
基金Specific Programs in Graduate Science and Technology Innovation of Beijing Forestry University(BLYJ201204)the Fundamental Research Funds for the Central Universities(TD-JC-2013-1)+1 种基金the Program for New Century Excellent Talents in University(NECT-10-0234)the National Natural Science Foundation of China(31200314).
文摘Aims Soil heterogeneity is common in natural habitats.It may trigger for-aging responses(placing more ramets and/or roots in nutrient-rich patches than in nutrient-poor patches)and further affect the growth of plants.However,the impact of soil heterogeneity on competitive interactions has been little tested.Methods We conducted a greenhouse experiment to investigate the effects of soil heterogeneity on intraspecific competition with a stolonif-erous herb Hydrocotyle vulgaris.We grew one(without com-petition)or nine ramets(with competition)of H.vulgaris under a homogeneous environment and two heterogeneous environ-ments differing in patch size(large or small patches).In the het-erogeneous treatment,the soil consisted of the same number of nutrient-rich and nutrient-poor patches arranged in a chessboard manner,and in the homogeneous treatment,the soil was an even mixture of the same amount of the nutrient-rich and the nutrient-poor soil.Important Findings Irrespective of intraspecific competition,H.vulgaris showed for-aging responses to soil heterogeneity in the large patch treatment,e.g.it produced significantly more biomass,ramets,aboveground mass and root mass in the nutrient-rich patches than in the nutrient-poor patches.In the small patch treatment,foraging responses were observed when intraspecific competition was present,but responses were not observed when there was no competition.However,we find a significant effect of soil heterogeneity on neither overall growth nor competitive intensity of H.vulgaris.Our results suggest that foraging responses to soil heterogeneity may not necessarily be adaptive and intraspecific competition may not be influenced by soil heterogeneity.
文摘Intratumoral heterogeneity including genetic and nongenetic mechanisms refers to biological differences amongst malignant cells originated within the same tumor.Both,cell differentiation hierarchy and stochasticity in gene expression and signaling pathways may result in phenotypic differences of cancer cells.Since a tumor consists of cancer cell clones that display distinct behaviours,changes in clonal proliferative behavior may also contribute to the phenotypic variability of tumor cells.There is a need to reveal molecular actions driving chemotherapeutic resistance in colon cancer cells.In general,it is widely hypothesized that therapeutic resistance in colorectal cancer is a consequence of the preferential survival of cancer stem cells.However,recent data regarding colorectal cancer suggest that resistance to anticancer therapy and post-therapeutic tumor reappearence could be related to variations of clonal dynamics.Understanding the interaction of genetic and nongenetic determinants influencing the functional diversity and therapy response of tumors should be a future direction for cancer research.
基金This work was supported in part by the Fulbright-Nehru Postdoctoral Research Fellowship,United States-India Educational Foundation,the Biosystem and Biomaterials Division,National Institute of Standards and Technology,Department of Commerce,and the Shobhit Institute of Engineering and Technology,Meerut,India(to DA),and by the Division of Intramural Research,National Institute of Dental and Craniofacial Research,a part of the Intramural Research Program,the National Institute of Health,Department of Health and Human Services(1ZIA DE000380 to PGR).
文摘Based on studies over the last several decades,the self-renewing skeletal lineages derived from bone marrow stroma could be an ideal source for skeletal tissue engineering.However,the markers for osteogenic precursors;i.e.,bone marrow-derived skeletal stem cells(SSCs),in association with other cells of the marrow stroma(bone marrow stromal cells,BMSCs)and their heterogeneous nature both in vivo and in vitro remain to be clarified.This review aims to highlight:i)the importance of distinguishing BMSCs/SSCs from other“mesenchymal stem/stromal cells”,and ii)factors that are responsible for their heterogeneity,and how these factors impact on the differentiation potential of SSCs towards bone.The prospective role of SSC enrichment,their expansion and its impact on SSC phenotype is explored.Emphasis has also been given to emerging single cell RNA sequencing approaches in scrutinizing the unique population of SSCs within the BMSC population,along with their committed progeny.Understanding the factors involved in heterogeneity may help researchers to improvise their strategies to isolate,characterize and adopt best culture practices and source identification to develop standard operating protocols for developing reproducible stem cells grafts.However,more scientific understanding of the molecular basis of heterogeneity is warranted that may be obtained from the robust high-throughput functional transcriptomics of single cells or clonal populations.
基金funded by the National Nature Science Foundation of China(grants 31570413 and 31870610)the Ten-Thousand-Talent Program of Zhejiang Province(2018R52016)the Joint Fund of Zhejiang Provincial Natural Science Foundation(Grant LTZ20C030001).
文摘Aims Plants can benefit from heterogeneous environments via disproportionately increasing resource harvesting in resource-rich patches.Their initial growing positions with respect to resource patches may thus have important influences on their performance and relative competitive ability.Such impacts may differ between species with contrasting spatial architectures.However,the potential influence of initial growing positions in heterogeneous environment on plant growth and competition has largely been ignored.Methods We grew the phalanx plant Carex neurocarpa and the guerrilla plant Bolboschoenus planiculmis alone or in competition in a heterogeneous environment consisting of high-and low-nutrient soil patches.In treatments without competition,one ramet of each species was grown in either a high-or a low-nutrient patch in the heterogeneous environment.In treatments with competition,a ramet of the target species was grown in either a high-or a low-nutrient patch,and a ramet of the competitor species was grown in the same patch as the target species or an adjacent patch with a different nutrient level.Important Findings Without competition C.neurocarpa produced more biomass and ramets when initially grown in a high-nutrient patch than when initially grown in a low-nutrient patch.With competition,these differences disappeared.Consequently,competitive intensity on C.neurocarpa was higher when it initially grew in a high-nutrient patch than when it initially grew in a low-nutrient patch.These impacts were independent of the initial position of its competitor.By contrast,the initial positions of B.planiculmis did not influence its growth or competitive response.Therefore,in heterogeneous environments,initial growing positions of clonal plants may influence their performance in competition-free environments and may also affect their relative competitive ability,and these effects may depend on spatial architecture of the plants.
