Deleted in breast cancer-1 (DBC-1) in the interface between metabolism,aging and cancer

DBC1 (deleted in breast cancer-1) is a nuclear protein that regulates cellular metabolism. Since alteration in cellular metabolism have been proposed to be the emerging ‘hallmark’ of cancer, it is possible that DBC1 may be implicated in the regulation of cancer cell energy metabolism. However, at this point any role of DBC1 in cancer is only speculative. In this review, we will discuss the new developments in DBC1 research, its molecular structure, regulatory roles and implication in metabolism, aging and cancer.     

Feeding of Acetes paraguayensis (Nobili) (Decapoda: Sergestidae) from the Parana River, Argentina

Feeding habits of Acetes paraguayensis (Hansen) were studied by examining the stomach content of specimens from two lakes. A. paraguayensis is omnivorous, feeding mainly on members of littoral-benthic and lotic communities. Algae, rotifers and microcrustaceans (copepods and cladocerans) are the more frequent items in the bulk of the stomach content. Oligochaeta and Diptera larvae were an alternative food source when available. Shrimp feeding habits difference between the two lakes may be due to the resource availability. A. paraguayensis are trophic linkers between limnetic and lotic habitats with an important role in the transportation of energy from the floodplain to the principal channel in the Paraná Rivers System.     

Social Perceptions of Biodiversity and Ecosystem Services in the Ecuadorian Amazon

The Amazon basin is widely recognized for its high biological and cultural diversity, enabling the provision of many ecosystem services. This study explores social perceptions of some of the features of biodiversity and ecosystem services in a tropical forest in Sangay Parish, Ecuador. Following a survey of residents, we identified three groups whose perceptions vary in relation to socioeconomic characteristics, cultural backgrounds, lifestyles, and the benefits obtained from the Sangay forest. Mestizo professionals, with a better socioeconomic situation, identify more regulation and cultural services; Shuar farmers have a comprehensive knowledge of biodiversity features and rely on provisioning services; and Shuar gatherers consume more forest products but are the least likely to formally recognize ecosystem services. We emphasize the importance of identifying social groups within a population and understanding their particular characteristics and perspectives before developing conservation and land use planning policies.     

The Phragmites communis Trin. chromosome complement in the Danube Delta

Summary This study elucidates the caryotypes in two varieties of Phragmites communis of the Danube Delta, by means of an original squash technique.The two varieties studied above coexist in the floating reed biocoenosis, but there exist different masses without any transitory forms. The flavescens and gigantissima varieties have different morphophysiological characteristics, the latter variety flowers later and shows the gigantism characteristics of polyploids.Comparative analysis of the caryotypes of the two varieties shows that the variety gigantissima is probably a natural auto-octopolyploid (2n = 8x = 96) of a relatively recent origin, as the chromosomes can be grouped into units of 4. The origin of the flavescens variety (2n = 4x = 48) is not certain, because the chromosomes can only be grouped in pairs within the caryotype. It seems that this variety, widespread all over the earth, has an older origin, since the rearrangements determining the present configuration of the caryotype occurred at chromosome level.     

The structures of human dihydroorotate dehydrogenase with and without inhibitor reveal conformational flexibility in the inhibitor and substrate binding sites

Inhibitors of dihydroorotate dehydrogenase (DHODH) have been suggested for the treatment of rheumatoid arthritis, psoriasis, autoimmune diseases, Plasmodium, and bacterial and fungal infections. Here we present the structures of N-terminally truncated (residues Met30-Arg396) DHODH in complex with two inhibitors: a brequinar analogue (6) and a novel inhibitor (a fenamic acid derivative) (7), as well as the first structure of the enzyme to be characterized without any bound inhibitor. It is shown that 7 uses the "standard" brequinar binding mode and, in addition, interacts with Tyr356, a residue conserved in most class 2 DHODH proteins. Compared to the inhibitor-free structure, some of the amino acid side chains in the tunnel in which brequinar binds and which was suggested to be the binding site of ubiquinone undergo changes in conformation upon inhibitor binding. Using our data, the loop regions of residues Leu68-Arg72 and Asn212-Leu224, which were disordered in previously studied human DHODH structures, could be built into the electron density. The first of these loops, which is located at the entrance to the inhibitor-binding pocket, shows different conformations in the three structures, suggesting that it may interfere with inhibitor/cofactor binding. The second loop has been suggested to control the access of dihydroorotate to the active site of the enzyme and may be an important player in the enzymatic reaction. These observations provide new insights into the dynamic features of the DHODH reaction and suggest new approaches to the design of inhibitors against DHODH.