Dental implants have restored masticatory function to over 100000000 individuals,yet almost 1000000 implants fail each year due to peri-implantitis,a disease triggered by peri-implant microbial dysbiosis.Our ability t...Dental implants have restored masticatory function to over 100000000 individuals,yet almost 1000000 implants fail each year due to peri-implantitis,a disease triggered by peri-implant microbial dysbiosis.Our ability to prevent and treat peri-implantitis is hampered by a paucity of knowledge of how these biomes are acquired and the factors that engender normobiosis.Therefore,we combined a 3-month interventional study of 15 systemically and periodontally healthy adults with whole genome sequencing,finescale enumeration and graph theoretics to interrogate colonization dynamics in the pristine peri-implant sulcus.We discovered that colonization trajectories of implants differ substantially from adjoining teeth in acquisition of new members and development of functional synergies.Source-tracking algorithms revealed that this niche is initially seeded by bacteria trapped within the coverscrew chamber during implant placement.These pioneer species stably colonize the microbiome and exert a sustained influence on the ecosystem by serving as anchors of influential hubs and by providing functions that enable cell replication and biofilm maturation.Unlike the periodontal microbiome,recruitment of new members to the peri-implant community occurs on nepotistic principles.Maturation is accompanied by a progressive increase in anaerobiosis,however,the predominant functionalities are oxygen-dependent over the 12-weeks.The peri-implant community is easily perturbed following crown placement,but demonstrates remarkable resilience;returning to pre-perturbation states within three weeks.This study highlights important differences in the development of the periodontal and peri-implant ecosystems,and signposts the importance of placing implants in periodontally healthy individuals or following the successful resolution of periodontal disease.展开更多
南方红壤丘陵区不同用材林下土壤侵蚀特征及其对有机碳(SOC)含量的影响与机制尚不明确。应用137Cs示踪技术,以桂北低山丘陵区的杂木林、马尾松林和桉树林为研究对象,研究不同林型和坡位下土壤侵蚀特征及其对SOC含量的影响。结果表明,土...南方红壤丘陵区不同用材林下土壤侵蚀特征及其对有机碳(SOC)含量的影响与机制尚不明确。应用137Cs示踪技术,以桂北低山丘陵区的杂木林、马尾松林和桉树林为研究对象,研究不同林型和坡位下土壤侵蚀特征及其对SOC含量的影响。结果表明,土壤侵蚀模数的范围为-3009.29—7472.95 t km^(-2)a^(-1),不同林型间表现为桉树林(4659.56 t km^(-2)a^(-1))>马尾松(938.99 t km^(-2)a^(-1))>杂木林(-1476.90 t km^(-2)a^(-1)),不同坡位为上坡(3416.71 t km^(-2)a^(-1))>中坡(621.80 t km^(-2)a^(-1))>下坡(83.14 t km^(-2)a^(-1))。与背景值相比,3个林地的上坡位均发生了土壤侵蚀,下坡位均发生了土壤沉积,桉树人工林的土壤侵蚀量较大。SOC和粘粒含量分别在不同林型和坡位上具有一致的分布规律,其平均值在不同林型间表现为桉树林<马尾松林<杂木林,不同坡位间表现为上坡<中坡<下坡。土壤侵蚀模数与SOC、粘粒含量均呈显著负相关,与粉粒含量呈显著正相关。结构方程模型表明,土壤侵蚀通过降低土壤粘粒含量从而减小SOC含量。在土壤侵蚀最大的上坡位,应注意防风固土措施的选择,如营造混交林。加强对人工林林下凋落物的保留与林下植被的恢复措施,以减少土壤侵蚀和增加土壤碳固存,充分发挥人工林在水土保持中的作用。展开更多
基金supported by National Institutes of Health R03DE027492 to Shareef Dabdoubsupported by National Institutes of Health,project number 7R01DE027857-06supported by National Institutes of Health R56DE033913 awarded to Purnima Kumar.
文摘Dental implants have restored masticatory function to over 100000000 individuals,yet almost 1000000 implants fail each year due to peri-implantitis,a disease triggered by peri-implant microbial dysbiosis.Our ability to prevent and treat peri-implantitis is hampered by a paucity of knowledge of how these biomes are acquired and the factors that engender normobiosis.Therefore,we combined a 3-month interventional study of 15 systemically and periodontally healthy adults with whole genome sequencing,finescale enumeration and graph theoretics to interrogate colonization dynamics in the pristine peri-implant sulcus.We discovered that colonization trajectories of implants differ substantially from adjoining teeth in acquisition of new members and development of functional synergies.Source-tracking algorithms revealed that this niche is initially seeded by bacteria trapped within the coverscrew chamber during implant placement.These pioneer species stably colonize the microbiome and exert a sustained influence on the ecosystem by serving as anchors of influential hubs and by providing functions that enable cell replication and biofilm maturation.Unlike the periodontal microbiome,recruitment of new members to the peri-implant community occurs on nepotistic principles.Maturation is accompanied by a progressive increase in anaerobiosis,however,the predominant functionalities are oxygen-dependent over the 12-weeks.The peri-implant community is easily perturbed following crown placement,but demonstrates remarkable resilience;returning to pre-perturbation states within three weeks.This study highlights important differences in the development of the periodontal and peri-implant ecosystems,and signposts the importance of placing implants in periodontally healthy individuals or following the successful resolution of periodontal disease.
文摘南方红壤丘陵区不同用材林下土壤侵蚀特征及其对有机碳(SOC)含量的影响与机制尚不明确。应用137Cs示踪技术,以桂北低山丘陵区的杂木林、马尾松林和桉树林为研究对象,研究不同林型和坡位下土壤侵蚀特征及其对SOC含量的影响。结果表明,土壤侵蚀模数的范围为-3009.29—7472.95 t km^(-2)a^(-1),不同林型间表现为桉树林(4659.56 t km^(-2)a^(-1))>马尾松(938.99 t km^(-2)a^(-1))>杂木林(-1476.90 t km^(-2)a^(-1)),不同坡位为上坡(3416.71 t km^(-2)a^(-1))>中坡(621.80 t km^(-2)a^(-1))>下坡(83.14 t km^(-2)a^(-1))。与背景值相比,3个林地的上坡位均发生了土壤侵蚀,下坡位均发生了土壤沉积,桉树人工林的土壤侵蚀量较大。SOC和粘粒含量分别在不同林型和坡位上具有一致的分布规律,其平均值在不同林型间表现为桉树林<马尾松林<杂木林,不同坡位间表现为上坡<中坡<下坡。土壤侵蚀模数与SOC、粘粒含量均呈显著负相关,与粉粒含量呈显著正相关。结构方程模型表明,土壤侵蚀通过降低土壤粘粒含量从而减小SOC含量。在土壤侵蚀最大的上坡位,应注意防风固土措施的选择,如营造混交林。加强对人工林林下凋落物的保留与林下植被的恢复措施,以减少土壤侵蚀和增加土壤碳固存,充分发挥人工林在水土保持中的作用。
