LEXEN: Longevity and Diversity of Microorganisms Entrapped in Tropical and Polar Ice Cores

LEXEN：热带和极地冰芯中微生物的寿命和多样性

• 批准号: 9714206
• 负责人: John Reeve
• 金额: $ 34万
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-10-01 至 2002-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9714206&HistoricalAwards=false
• 关键词: LEXEN; Longevity; Diversity; Microorganisms; Entrapped

This project is to determine the phylotypes, abundance and antiquity of microorganisms that can be resuscitated from within ice cores taken from such diverse environments as the Tibetan Plateau, the South American Andes, and both polar regions. PCR-amplified small subunit (16S and 18S) rDNAs will be cloned and sequenced to determine the range of phylotypes that are, or were, present in these ice cores that are refractory to laboratory culture. The experiments are conceptually very simple, and technically require only routine microbiological and molecular biology procedures; however, preventing contamination with microorganisms and nucleic acids from exogenous sources will be critical. An automated ice-sampling device will therefore be constructed specifically to eliminate this problem. The ice cores are archived under carefully controlled conditions at the BPRC, and several cores area available from most locations, so that multiple samplings to evaluate different procedures and to confirm positive results are possible without field trips. The experiments proposed will determine the longevity of microorganisms entrapped in ice under different environmental conditions, the diversity of microorganisms deposited at the same geographical sites, but separated by thousands, or possibly by hundreds of thousands of years, and the diversity of microorganisms deposited at the same archeological times but at geographically very different and remote locations. This might be the first concerted effort to apply PCR technology to amplify material from within very ancient ice cores, and it seems very likely that "extinct" genes, or at least fragments of extinct genes will be amplified, facilitating intriguing comparisons with the sequences of their contemporary homologs. Although many of the core isolates are likely to be Actinomycetes, evaluating novel antibiotic synthesis by core isolates is beyond the exploratory goals of this proposal. Determining the antibiotic resistance patterns of microorgan isms that were entrapped in ice before the widespread use of antibiotics will, however, be routinely undertaken.

该项目旨在确定可以从青藏高原、南美安第斯山脉和两极地区等不同环境的冰芯中复苏的微生物的系统类型、丰度和古老程度。经聚合酶链式反应扩增的小亚基(16S和18S)rDNA将被克隆和测序，以确定这些冰芯中存在或曾经存在的系统类型的范围，这些冰芯对实验室培养是困难的。这些实验在概念上非常简单，在技术上只需要常规的微生物和分子生物学程序；然而，防止受到外来来源的微生物和核酸的污染将是至关重要的。因此，将专门建造一种自动冰样装置来消除这一问题。BPRC的冰芯在严格控制的条件下存档，大多数地点都有几个冰芯区域，因此无需实地考察，就可以进行多次取样，以评估不同的程序并确认积极的结果。拟议的实验将确定在不同环境条件下被困在冰中的微生物的寿命，沉积在相同地理位置但相隔数千年或可能数十万年的微生物的多样性，以及沉积在相同考古时代但地理上非常不同的偏远地点的微生物的多样性。这可能是应用聚合酶链式反应技术从非常古老的冰芯中扩增物质的第一次协同努力，而且看起来很可能会扩增已灭绝的基因，或者至少已灭绝基因的片段，从而便于与其同时代同源物的序列进行有趣的比较。虽然许多核心分离株很可能是放线菌，但评估核心分离株合成新的抗生素超出了本提案的探索目标。然而，在抗生素广泛使用之前，确定被困在冰中的微器官中毒的抗生素耐药性模式将是例行公事。