A selenite-induced decrease in the lipid content of a red alga

Two unicellular marine algae (Dunaliella primolecta and Porphyridium cruentum) have been found to contain a selenium-inducible, non-enzymatic glutathione peroxidase activity when cultured in the presence of selenite. To test the possibility that selenium functions in vivo as an antioxidant in these algae, a detailed examination of the lipid content of algae cultured in the presence or absence of selenite was conducted. If selenium augments the antioxidant defenses of algal cells, an increase in the content of oxidation-sensitive lipids would be expected. The fatty acid, chlorophyll, phospholipid and glycolipid content of the green alga D. primolecta was not affected by growth in selenite. At low light intensity there was a moderate decrease in the chlorophyll and polyunsaturated fatty acid content of the red alga P. cruentum when cultured in selenite. At higher light intensity the content of all fatty acids, phospholipid, glycolipid, chlorophyll, carotenoid and phycoerythrin decreased in P. cruentum grown in selenite. Since growth in selenite did not increase the quantity of oxidation-sensitive lipids in either alga, there is no evidence for an in vivo functioning of selenium as an antioxidant. Instead, the observed decrease in lipids of the red alga P. cruentum can best be explained as a selenite-induced oxidative effect.     

Acetyl-CoA Synthetase 2: A Critical Linkage in Obesity-Induced Tumorigenesis in Myeloma

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Identification and quantification of subsets of mononuclear inflammatory cells in melanocytic and other human tumors

We used monoclonal antibodies and an indirect immunoperoxidase technique to identify mononuclear inflammatory cells associated with human tumors. The absolute number of the different types of inflammatory cells was assessed by using a point-counting technique. We studied tissues from six primary cutaneous melanomas, six metastatic melanomas, eight melanocytic nevi, 14 breast cancers, seven examples of fibrocystic disease of the breast, 11 lung cancers, and six colon cancers. Virtually all tumors were associated with substantial numbers of T lymphocytes (Leu3a-positive T helper-inducer cells predominating) and macrophages. Primary melanomas contained significantly more T lymphocytes (P less than .002), macrophages (P less than .005), and Langerhans/dendritic cells (P less than .002) than nevi or normal skin and had a higher proportion of T cells than metastatic melanomas (P less than .01). Breast cancers contained more T lymphocytes and macrophages than occur with fibrocystic disease (P less than .0001 and P less than .002, respectively) and more B lymphocytes. Cancers of the lung and colon contained moderate numbers of T lymphocytes and macrophages; however, colon cancers contained a higher proportion of B cells. Leu7-positive NK/K cells were noted in small numbers in all tumors examined.     

Myostatin maps to the interval containing the bovine mh locus

Myostatin (GDF-8) is a member of the transforming growth factor-β superfamily and plays a role in muscle growth and development. Mice having targeted disruption of this gene display marked increases in muscle mass, a phenotype similar to the muscular hypertrophy (mh) in several cattle breeds. Physical mapping data developed from YAC clones indicate the bovine myostatin gene lies close to the centromere of bovine Chromosome (Chr) 2 (BTA2) at 2q11, indistinguishable from the cytogenetic location of the mh locus. In addition, a polymorphism in the second intron of the gene was used to show that myostatin maps within the interval previously shown to contain mh. These data suggest myostatin may be the gene causing muscular hypertrophy in cattle. Received: 19 June 1997 / Accepted: 2 July 1997