Planktonic microbial communities often appear stable over periods of days and thus tight links are assumed to exist between different functional groups (i.e. producers and consumers). We examined these links by characterizing short-term temporal correspondences in the concentrations and activities of microbial groups sampled from 1 m depth, at a coastal site of the N.W. Mediterranean Sea, in Se...

The marine nitrogen (N) cycle is a complex network of biological transformations in different N pools. The linkages among these different reservoirs are often poorly understood. Traditional methods for measuring N uptake rely on bulk community properties and cannot provide taxonomic information. (15)N-based stable isotope probing (SIP), however, is a technique that allows detection of uptake of...

Recent reports documenting very high viral abundances in seawater have led to increased interest in the role of viruses in aquatic environments and a resurgence of the hypothesis that viruses are significant agents of bacterial mortality. Synechococcus spp., small unicellular cyanobacteria that are important primary producers at the base of the marine food web, were used to assess this hypothes...

SUMMARY The unicellular cyanobacterium Synechococcus PCC 7942 has been used as a model organism for studies of prokaryotic circadian rhythms, carbon-concentrating mechanisms, response to a variety of nutrient and environmental stresses, and cell division. This paper presents the results of the first proteomic exploratory study of Synechococcus PCC 7942. The proteome was analyzed using two-dimen...

Hourly, year-round flow cytometry has made it possible to relate seasonal environmental variability the population dynamics of smallest, most abundant phytoplankton on Northeast US Shelf. To evaluate whether insights from these data extend Synechococcus farther shore, we analyze measurements continuously underway systems 21 cruises traveling between Martha's Vineyard Coastal Observatory (MVCO) ...

This study presents the response of autotrophic pico- and nanoplankton to southwest monsoon-associated hydrographical transformations in the Cochin backwaters (CBW), the largest monsoonal estuary along the west coast of India. By the onset of the southwest monsoon, the euhaline/mesohaline conditions in the downstream/upstream of CBW usually transform into oligohaline/limnohaline. The flow cytom...

The excitation-wavelength dependence of the excited-state dynamics of monomeric and trimeric Photosystem I (PSI) particles from Synechocystis PCC 6803 as well as trimeric PSI particles from Synechococcus elongatus has been studied at room temperature using time-resolved fluorescence spectroscopy. For aselective (400 nm), carotenoid (505 nm), and bulk chlorophyll (approximately 650 nm) excitatio...

The P(II) proteins are found in all three domains of life as key integrators of signals reflecting the balance of nitrogen and carbon. Genetic inactivation of P(II) proteins is typically associated with severe growth defects or death. However, the molecular basis of these defects depends on the specific functions of the proteins with which P(II) proteins interact to regulate nitrogen metabolism...

Cyanobacteria of the genera Synechococcus and Prochlorococcus are the most abundant photosynthetic organisms on earth, occupying a key position at the base of marine food webs. The cynS gene that encodes cyanase was identified among bacterial, fungal, and plant sequences in public databases, and the gene was particularly prevalent among cyanobacteria, including numerous Prochlorococcus and Syne...

Bacterial toxin-antitoxin (TA) systems are genetic elements composed of a toxin gene and its cognate antitoxin, with the ability to regulate growth. TA systems have not previously been reported in marine Synechococcus or Prochlorococcus. Here we report the finding of seven TA system pairs (Type II) in the estuarine Synechococcus CB0101, and their responses of these TA genes to under different s...