کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5522489 1545980 2017 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Increased production of outer membrane vesicles by cultured freshwater bacteria in response to ultraviolet radiation
ترجمه فارسی عنوان
افزایش تولید ویولون های غشای بیرونی باکتری های کشت شده آب شیرین در پاسخ به اشعه ماوراء بنفش
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی بیوتکنولوژی یا زیست‌فناوری
چکیده انگلیسی

Secretion of membrane vesicles is an important biological process of both eukaryotic and prokaryotic cells. This process has been characterized in pathogenic bacteria, but is less clear in non-pathogenic bacteria from aquatic ecosystems. Here, we investigated, for the first time, the process of formation of outer membranes vesicles (OMVs), nanoscale vesicles extruded from the outer membrane (OM) of gram-negative bacteria, in cultures of freshwater bacteria after exposure or not to ultraviolet radiation (UVR) as an environmental stressor. Non-axenic cultures of freshwater bacteria isolated from a Brazilian aquatic ecosystem (Funil reservoir) were exposed or not to UVR (UVA + UVB) over a 3 h period, during which cell density, viability and ultrastructure were analyzed. First, we showed that UVR induce bacterial death. UVR triggered significant negative effect on cell density after 3 h of UVR treatment. This decrease was directly associated with cell death as revealed by a cell viability fluorescent probe that enables the distinction of live/dead bacteria. Transmission electron microscopy (TEM) revealed changes indicative of cell death after 3 h of UVR exposure, with significant increase of damaged cells compared to the control group. Second, we demonstrated that gram-negative bacteria release OMVs during normal growth and after UVR exposure. OMVs were clearly identified as round, membrane-bound vesicles budding off from the bacterial OM as isolated or clustered vesicles or free in the extracellular medium. Remarkably, quantitative TEM analyses showed that bacteria respond to UVR with increased formation of OMVs. Moreover, while OMVs numbers per intact or damaged cell did not differ in the untreated group, UVR led to a higher vesiculation by bacteria in process of death. This means that degenerating bacteria release OMVs before lysis and that this secretion might be an adaptive/protective response to rapid changes in environmental conditions such as UV radiation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Microbiological Research - Volume 194, January 2017, Pages 38-46
نویسندگان
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