Skip to main content

Ferran Garcia-Pichel

We estimated global cyanobacterial biomass in the main reservoirs of cyanobacteria on Earth: marine and freshwater plankton, arid land soil crusts, and endoliths. Estimates were based on typical population density values as measured during our research, or as obtained from literature surveys, which were then coupled with data on global geographical area coverage. Among the marine plankton, the global biomass of Prochlorococcus reaches 120 × 10^12 grams of carbon (g C), and that of Synechoccus some 43 × 10^12 g C. This makes Prochlorococcus and Synechococcus, in that order, the most abundant cyanobacteria on Earth. Tropical marine blooms of Trichodesmium account for an additional 10 × 10^12 g C worldwide. In terrestrial...
thumbnail
We compared the community structures of cyanobacteria in four biological desert crusts from Utah's Colorado Plateau developing on different substrata. We analyzed natural samples, cultures, and cyanobacterial filaments or colonies retrieved by micromanipulation from field samples using microscopy, denaturing gradient gel electrophoresis, and sequencing of 16S rRNA genes. While microscopic analyses apparently underestimated the biodiversity of thin filamentous cyanobacteria, molecular analyses failed to retrieve signals for otherwise conspicuous heterocystous cyanobacteria with thick sheaths. The diversity found in desert crusts was underrepresented in currently available nucleotide sequence databases, and several...
We used metabolic inhibitors and radiolabelled tracers to investigate the biosynthetic pathway for mycosporines (mycosporine-like amino acids) in the facultatively heterotrophic cyanobacterium (blue-green alga) Chlorogloeopsis sp. strain PCC 6912. 14C-pyruvate was taken up and resulted in labelling of the core cyclohexenone, whereas feeding with 14C-acetate did not label cyclohexenone, in spite of strong cellular uptake. In addition, mycosporine synthesis was depressed in the presence of externally administered tyrosine (5 mM), a known feedback inhibitor of the shikimic acid pathway in cyanobacteria. We thus conclude that the mycosporine core cyclohexenone in cyanobacteria is derived from the shikimate pathway,...
Bacterial strain CP183-8(T) was isolated from biological soil crusts collected in the Colorado Plateau, USA. Cells of this strain were aerobic, non-motile, Gram-negative, psychrotolerant and formed beaded chains in the stationary growth phase. They contained C(16 : 1)omega5c and C(16 : 1)omega7c as major fatty acids. 16S rRNA gene sequence analysis assigned the strain to the genus Dyadobacter. However, it shared a sequence similarity of only 95.88 % with the type strain of Dyadobacter fermentans, NS114(T). Because it also exhibited a significant number of phenotypic and chemotaxonomic differences from D. fermentans, it is described as a novel second species in the genus Dyadobacter, with the name Dyadobacter crusticola...
The morphologies, halotolerances, temperature requirements, pigment compositions and 16S rRNA gene sequences of five culture collection strains and six novel isolates of cyanobacteria with helical, tightly coiled trichomes were investigated. All strains were very similar morphologically and could be assigned to the genus Spirulina (or section Euspirulina sensu Geitler), according to traditional classification. However, the isolates showed significantly different requirements for salinity and temperature, which were in accordance with their respective environmental origins. The genetic divergence among the strains investigated was large. The results indicate the drastic underestimation of the physiological and phylogenetic...
View more...
ScienceBase brings together the best information it can find about USGS researchers and offices to show connections to publications, projects, and data. We are still working to improve this process and information is by no means complete. If you don't see everything you know is associated with you, a colleague, or your office, please be patient while we work to connect the dots. Feel free to contact sciencebase@usgs.gov.