讲座报告 Seminar
[午餐交流会] 第七十讲:How siderophores really work in natural matrices?  
Luncheon Seminars #70: How siderophores really work in natural matrices?
【时间 Time】:2017-5-8 (星期一) 11:40-13:30(讲座于12:20开始)    【浏览次数 Count】:647   【发布时间 Updated】:2017-5-3
【地点 Venue】:周隆泉楼 A3-206   A3-206, Zhou Long Quan Bldg
【主讲人 Speaker】:Dr. Jean-Philippe Bellenger,副教授    , Associate Professor
【来访单位 Institution】:谢布克大学,加拿大    University of Sherbrooke, Canada
【邀请人 Host】:午餐交流会(史大林)  Dr. Dalin Shi      【联络人 Contact】:施薇   Vera Shi, vera_shiwei@xmu.edu.cn

 

EDUCATION:

-       2001-2005, PhD Biogeochemistry, ECPM, CGS, Louis Pasteur University, Strasbourg, France

-       2001, Advanced degree in Soil Science, INRA-ENSAM (National institute of agronomic research), Montpellier & Henri Poincare University, Nancy France.

-       2000, Master’s degree in Cellular Biology and Physiology, Claude Bernard University, Lyon, France

-       1999, Master’s degree in Geosciences, Claude Bernard University, Lyon, France

 

RESEARCH INTEREST:

-       Trace metal and nitrogen biogeochemistry

 

WORK EXPERIENCE

-       2010 to present, Associate Professor, and Chair holder of the Canadian Research Chair in Terrestrial Biogeochemistry, Chemistry department, Sherbrooke University, Qc, Canada.

-       2005-2010, Research associate, Princeton Environmental Institute, Princeton University, NJ, USA.

 

ABSTRACT:

Since trace metal bioavailability, while potentially toxic, affects key enzymatic activities, the cycling of metals in the environment can critically impact the cycling of major nutrients such as nitrogen or carbon. For instance, iron (Fe) is the most important metal in biology. Despite its abundance on earth its bioavailability is very low in both terrestrial and marine ecosystems, due to its very low solubility in oxic solution, not greater than 10-18 M at pH 7. To overcome the challenge of Fe acquisition, many microorganisms produce siderophores, low molecular weight ligand with high affinity for Fe, to retrieve Fe from natural sources. Siderophores are released in the environment, under Fe stress, to promote Fe acquisition by impacting extracellular Fe speciation. This process strongly relies on the ability of produced siderophores to compete with natural Fe sources to from soluble Fe complexes.

However, while siderophores achieve very high affinity for Fe, the complexation of Fe from oxids and organic matter sources is often affected by very low kinetics (several hours, days and more). This is a major constrain to metal acquisition, Fe homeostasis and bacterial growth. Our understanding of how siderophore-Fe complexes are retrieved by bacteria once formed in the extracellular matrix also remains elusive.

Besides the production of siderophores, another important feature of most microorganisms is their capacity to form multicellular communities embedded in a self-secreted extracellular matrix; biofilms.  Biofilms are ubiquitous in the environment, and provide many advantages for the microbial communities such as protection against environmental stresses and increased sharing of resources.

Here, I will present recent results showing that, in the model organism Bacillus subtilis, biofilm formation responds to intracellular Fe limitation. I will also show evidences that the production of the biofilm matrix improves the efficiency of siderophores to recruit Fe from unavailable sources. Finally I will discuss the importance to further study the role of biofilm formation on Fe, and other essential trace metals, acquisition in terrestrial, aquatic and marine (coastal and open-ocean) ecosystems.

________________________________________________________

本次午餐会将为报名参加的师生提供午餐,所有午餐会的报名都通过网络进行。请老师同学们访问MEL网页(http://mel.xmu.edu.cn/lecture.asp?id=1),在本次午餐会的报名一栏填写并提交。
本讲座将发布当天仅开放给科研人员、技术人员、博士后、访问学者等教师优先报名,第二天起开放给全体师生报名。学生应在规定时间内报名,如提前以教师的名义报名,将导致报名无效。
本周五下午4点为截止报名时间,总报名人数限制在100名以内。如未及时报上名,可于12:20直接到场听报告。如已报名但因事不能参加,也请在周五下午4点前告知。
午餐会一如既往地欢迎大家的关注,如有兴趣做讲座的老师。欢迎与我们联系。