טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentAia Oz
SubjectDiversity and Classification of Aerobic Anoxygenic
Photosynthetic Bacteria in the Mediterranean and
Red Seas
DepartmentDepartment of Biology
Supervisor Full Professor Beja Oded


Abstract

Anoxygenic photosynthesis is carried out by various bacterial groups, which differ by their major pigments and by the type of the reaction center. In the process of anoxygenic photosynthesis, water is not split and oxygen is not evolved.

Bacteriochlorophyll a -containing Aerobic Anoxygenic Phototrophs (AAnP) have been proposed to account for up to 11% of the total marine surface water microbial community and to potentially have great ecological importance in the world's oceans.  Cultures of AAnPs revealed the existence of two major types, both belonging to the α-proteobacteria.  Recently, environmental and genomic data based on analysis of the pufM gene encoding the M subunit of the photosynthetic reaction center, identified the existence of a as well as possible b- or  g-like proteobacteria among AAnPs in the Pacific Ocean.  In this work, analyzes were made of environmental samples from the Red and Mediterranean seas using pufL, pufM, as well as bchX and bchL genes (encoding for proteins in the bacteriochlorophyll biosynthetic pathway) as markers.  The data reveal the dominance of Roseobacter-like AAnPs in the seasons analyzed in the Red and Mediterranean Seas as compared to the Pacific Ocean.  Furthermore, an analysis of a whole BAC insert from the Red Sea which contains an almost complete photosynthetic gene cluster, adds to the validity of the classification of the environmental genes as Roseobacter species.   Moreover, it contains a unique arrangement of its puf operon (which encodes structural proteins), an arrangement never before seen in AAnPs.