Oxyrrhis marina Dujardin is a non-photosynthetic dinoflagellate whose obvious mode of nutrition is phagotrophy. The method of feeding was described by Barker (1935). It is an extremely euryhaline and hardy organism and is apparently very successful in brackish habitats such as supralittoral rock pools and ditches (Droop, 1953a). Owing to the ease with which it can be cultivated Oxyrrhis is a ch...

Soluble immune response suppressor (SIRS), a protein of Mr 14,000, is a lymphokine produced by interferon- or concanavalin A-activated suppressor T cells and is oxidized to its activated form, SIRSox, by H2O2 produced by macrophages. SIRSox inhibits antibody secretion by B lymphocytes and cell division by normal or transformed cell lines. Effects of purified growth factors on suppression of ant...

All eggs are activated at fertilization by an increase in intracellular free Ca2+. How the spermatozoa triggers the release of intracellular Ca2+ has not been established in any species. One hypothesis is that spermatozoa introduce a Ca(2+)-releasing factor into the cytoplasm after gamete membrane fusion. It has been suggested that spermatozoa may introduce Ca2+ itself, or a small molecular wei...

Bone metastasis is a common event and a major cause of morbidity in prostate cancer patients. After colonization of bone, prostate cells induce an osteoblastic reaction which is not associated with marrow fibrosis (i.e., osteoblast but not fibroblast proliferation). In the present study we test the hypothesis that the tumoral prostatic cell line (PC-3) secretes factors that block the osteoblast...

The commensal microbiota modulates immunological and metabolic aspects of the intestinal mucosa contributing to development of human gut diseases including inflammatory bowel disease. The host/microbiota interaction often referred to as a crosstalk, mainly focuses on the effect of the microbiota on the host neglecting effects that the host could elicit on the commensals. Colonic microenvironmen...

Mesenchymal stem cells (MSCs) are multipotent stromal cells that are identified by in vitro plastic adherence, colony-forming capacity, expression of a panel of surface molecules, and ability to differentiate at least toward osteogenic, adipogenic, and chondrogenic lineages. They also produce trophic factors with immunomodulatory, proangiogenic, and antiapoptotic functions influencing the behav...

Considerable information on the intracellular localization of enzymes has been obtained in recent years through the technique of differential centrifugation of sucrose homogenates of tissues and subsequent testing of the fractions for enzyme activity. One of the results of this work has been the demonstration that rat liver mitochondria (Mw) are capable of completely oxidizing a wide variety of...

Atmospheric iron (Fe) can be a significant source of nutrition for phytoplankton inhabiting remote oceans, which in turn has a large influence on the Earth’s climate. The bioavailability of Fe in aerosols depends mainly on the fraction of soluble Fe (= [FeSol]/[FeTotal], where [FeSol] and [FeTotal] are the atmospheric concentrations of soluble and total Fe, respectively). However, the numerous ...