A novel photosynthetic strategy for adaptation to low-iron aquatic environments.

Iron (Fe) availability is a major limiting factor for primary production in aquatic environments. Cyanobacteria respond to Fe deficiency by derepressing the isiAB operon, which encodes the antenna protein IsiA and flavodoxin. At nanomolar Fe concentrations, a PSI-IsiA supercomplex forms, comprising a PSI trimer encircled by two complete IsiA rings.

Biospheric primary production during an ENSO transition.

The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) provides global monthly measurements of both oceanic phytoplankton chlorophyll biomass and light harvesting by land plants. These measurements allowed the comparison of simultaneous ocean and land net primary production (NPP) responses to a major El Niño to La Niña transition. Between September 1997 and August 2000, biospheric NPP varied by 6 petagrams of carbon per year (from 111 to 117 petagrams of carbon per year).

Inhibition of development of murine melanoma lung metastases by systemic administration of recombinant platelet factor 4.

Background: When administered locally, recombinant platelet factor 4 (rPF4), a known angiogenesis inhibitor, has been shown to effectively suppress murine melanoma and human colon carcinoma primary tumor growth in mice. It was tentatively concluded that this effect was due to the inhibition of tumor neovascularization.

Purpose: This study has evaluated the effects of systemically administered rPF4 on the growth and establishment of experimental B16F10 melanoma lung metastases in syngeneic mice.

Induction of phorbol ester responsiveness in conventional B cells after activation via surface Ig.

The signals required to induce S phase entry in murine splenic B cells were found to be altered by prolonged treatment with low doses of anti-Ig antibody. Whereas fresh splenic B cells are stimulated by the combination of a phorbol ester protein kinase C agonist plus a calcium ionophore, anti-Ig-treated splenic B cells were stimulated by phorbol ester alone, in the absence of a comitogen. The majority of these phorbol ester responsive B cells expressed CD5.