Complete Genome Sequences of Two Phylogenetically Distinct Strains Isolated from the Atlantic and Pacific Oceans.

The complete genome sequences of two chemoautotrophic nitrite-oxidizing bacteria of the genus are reported. Nitrospina gracilis strain Nb-211 was isolated from the Atlantic Ocean, and sp. strain Nb-3 was isolated from the Pacific Ocean.

Dynamic diel proteome and daytime nitrogenase activity supports buoyancy in the cyanobacterium Trichodesmium.

Cyanobacteria of the genus Trichodesmium provide about 80 Tg of fixed nitrogen to the surface ocean per year and contribute to marine biogeochemistry, including the sequestration of carbon dioxide. Trichodesmium fixes nitrogen in the daylight, despite the incompatibility of the nitrogenase enzyme with oxygen produced during photosynthesis. While the mechanisms protecting nitrogenase remain unclear, all proposed strategies require considerable resource investment.

Ground Level Deployment of Wireless Sensor Networks: Experiments, Evaluation and Engineering Insight.

In this paper, we are interested in characterizing the link properties of a wireless sensor network with nodes deployed at ground level. Such a deployment is fairly common in practice, e.g.

Clinical usefulness of end-tidal CO profiles during incremental exercise in patients with chronic thromboembolic pulmonary hypertension.

Introduction: Great ventilation to carbon dioxide output (ΔV˙E/ΔV˙CO) and reduced end-tidal partial pressures for CO (PetCO) during incremental exercise are hallmarks of chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (IPAH). However, CTEPH is more likely to involve proximal arteries, which may lead to poorer right ventricle-pulmonary vascular coupling and worse gas exchange abnormalities. Therefore, abnormal PetCO profiles during exercise may be more prominent in patients with CTEPH and could be helpful to indicate disease severity.

Complete genome of Nitrosospira briensis C-128, an ammonia-oxidizing bacterium from agricultural soil.

Nitrosospira briensis C-128 is an ammonia-oxidizing bacterium isolated from an acid agricultural soil. N. briensis C-128 was sequenced with PacBio RS technologies at the DOE-Joint Genome Institute through their Community Science Program (2010).

Contrasting cardiopulmonary responses to incremental exercise in patients with schistosomiasis-associated and idiopathic pulmonary arterial hypertension with similar resting hemodynamic impairment.

It has been reported that schistosomiasis-associated PAH (Sch-PAH) has a more benign clinical course compared with idiopathic PAH (IPAH). We therefore hypothesized that Sch-PAH subjects would present with less impaired cardiopulmonary and metabolic responses to exercise than IPAH patients, even with similar resting pulmonary hemodynamic abnormalities. The aim of this study was to contrast physiologic responses to incremental exercise on cycle ergometer between subjects with Sch-PAH and IPAH.

Optimizing the evaluation of excess exercise ventilation for prognosis assessment in pulmonary arterial hypertension.

Background: Increased ventilatory (.VE) response to carbon dioxide output (.VCO2) is a key finding of incremental cardiopulmonary exercise testing in both heart failure and pulmonary arterial hypertension (PAH).

Heart rate recovery in pulmonary arterial hypertension: relationship with exercise capacity and prognosis.

Background: Delayed postexercise heart rate recovery (HRR) has been associated with disability and poor prognosis in chronic cardiopulmonary diseases. The usefulness of HRR to predict exercise impairment and mortality in patients with pulmonary arterial hypertension (PAH), however, remains largely unexplored.

Methods: Seventy-two patients with PAH of varied etiology (New York Heart Association classes I-IV) and 21 age- and gender-matched controls underwent a maximal incremental cardiopulmonary exercise test (CPET), with heart rate being recorded up to the fifth minute of recovery.

Iron conservation by reduction of metalloenzyme inventories in the marine diazotroph Crocosphaera watsonii.

The marine nitrogen fixing microorganisms (diazotrophs) are a major source of nitrogen to open ocean ecosystems and are predicted to be limited by iron in most marine environments. Here we use global and targeted proteomic analyses on a key unicellular marine diazotroph Crocosphaera watsonii to reveal large scale diel changes in its proteome, including substantial variations in concentrations of iron metalloproteins involved in nitrogen fixation and photosynthesis, as well as nocturnal flavodoxin production. The daily synthesis and degradation of enzymes in coordination with their utilization results in a lowered cellular metalloenzyme inventory that requires ∼40% less iron than if these enzymes were maintained throughout the diel cycle.

Phenotypic and genotypic characterization of multiple strains of the diazotrophic cyanobacterium, Crocosphaera watsonii, isolated from the open ocean.

Diazotrophic cyanobacteria have long been recognized as important sources of reduced nitrogen (N) and therefore are important ecosystem components. Until recently, species of the filamentous cyanobacterium Trichodesmium were thought to be the primary sources of fixed N to the open ocean euphotic zone. It is now recognized that unicellular cyanobacteria are also important contributors, with members of the oligotrophic genus Crocosphaera being the only cultured examples.

Resistance to co-occurring phages enables marine synechococcus communities to coexist with cyanophages abundant in seawater.

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 hypothesis.

A cyanobacterium capable of swimming motility.

A novel cyanobacterium capable of swimming motility was isolated in pure culture from several locations in the Atlantic Ocean. It is a small unicellular form, assignable to the genus Synechococcus, that is capable of swimming through liquids at speeds of 25 micrometers per second. Light microscopy revealed that the motile cells display many features characteristic of bacterial flagellar motility.

Production of NO(2) and N(2)O by Nitrifying Bacteria at Reduced Concentrations of Oxygen.

Pure cultures of the marine ammonium-oxidizing bacterium Nitrosomonas sp. were grown in the laboratory at oxygen partial pressures between 0.005 and 0.

Determination of bacterial number and biomass in the marine environment.

Three techniques for the measurement of bacterial numbers and biomass in the marine environment are described. Two are direct methods for counting bacteria. The first employs an epifluorescence microscope to view bacteria that have been concentrated on membrane filters and stained with acridine orange.

Fine structure of the cytomembranes of Nitrosocystis oceanus.

Thin-sectioned, negatively stained, and freeze-etched preparations of Nitrosocystis oceanus cytomembranes were compared. The cytomembranes in freeze-etched cells were covered with 80- to 120-A particles. When cells were disrupted and differentially centrifuged, various membrane and particle fractions were obtained.