Development of a Cell Culture System From Gill Explants of the Grouper, Epinephelus malabaricus (Bloch and Shneider)

A cell culture system was developed successfully from gill explants of the Malabar grouper, Epinephelus malabaricus. Gill tissue samples aseptically excised from healthy juveniles of E. malabaricus were explanted in Leibovitz’ L-15 medium supplemented with 0.07 M NaCl and 20% fetal bovine serum (FBS). A mixture of different types of cells emerged from the explants, and these cells were observed to spread and attach to the culture flasks from the second day onwards. Confluent monolayers comprising epithelioid as well as fibroblast-like cells were formed within ten days. The cells were found to grow well at 28 + 2°C. The cell monolayers were subcultured by trypsinization and seeded into new flasks, which produced confluent monolayers comprising predominantly epithelioid-like cells in subsequent passages

A cell culture system developed from heart tissue of the greasy grouper, Epinephelus tauvina (Forsskal 1775) by enzymatic dissociation

Heart tissue samples aseptically excised from healthy juveniles of the grouper, Epinephelus tauvina were subjected to enzymatic dissociation using 0.25 % trypsin solution, under aseptic conditions. The resultant cells were suspended in Leibovitz' L-15 medium supplemented with 20 % fetal bovine serum. The cells were subsequently seeded into 25 cm2 tissue culture flasks at a density of 106 ml-1 and incubated at 28 ± 2°C. Cells showed spreading and attachment to the culture flasks within 24 h and formed monolayers comprising of epithelioid as well as fibroblast-like cells within 20 days. A confluent monolayer filling the flask surface comprising predominantly fibroblastic cells was formed within 30 to 35 days. The cell monolayer was harvested for passage by trypsinisation, which formed successful monolayers in subsequent subcultures

Human PXR Forms a Tryptophan Zipper-Mediated Homodimer †

The human nuclear receptor pregnane X receptor (PXR) responds to a wide variety of potentially harmful chemicals and coordinates the expression of genes central to xenobiotic and endobiotic metabolism. Structural studies reveal that the PXR ligand binding domain (LBD) uses a novel sequence insert to form a homodimer unique to the nuclear receptor superfamily. Terminal β-strands from each monomeric LBD interact in an ideal antiparallel fashion to bury potentially exposed surface β-strands, generating a ten-stranded intermolecular β-sheet. Conserved tryptophan and tyrosine residues lock across the dimer interface and provide the first tryptophan-zipper (Trp-Zip) interaction observed in a native protein. We show using analytical ultracentrifugation that the PXR LBD forms a homodimer in solution. We further find that removal of the interlocking aromatic residues eliminates dimer formation but does not affect PXR's ability to interact with DNA, RXRα, or ligands. Disruption of the homodimer significantly reduces receptor activity in transient transfection experiments, however, and effectively eliminates the receptor's recruitment of the transcriptional coactivator SRC-1 both in vitro and in vivo. Taken together, these results suggest that the unique Trp-Zip-mediated PXR homodimer plays a role in the function of this nuclear xenobiotic receptor

Unconditionally secure digital signatures implemented in an eight-user quantum network

The ability to know and verifiably demonstrate the origins of messages can often be as important as encrypting the message itself. Here we present an experimental demonstration of an unconditionally secure digital signature (USS) protocol implemented for the first time, to the best of our knowledge, on a fully connected quantum network without trusted nodes. We choose a USS protocol which is secure against forging, repudiation and messages are transferrable. We show the feasibility of unconditionally secure signatures using only bi-partite entangled states distributed throughout the network and experimentally evaluate the performance of the protocol in real world scenarios with varying message lengths

Not Available

Not AvailableHeart tissue samples aseptically excised from healthy juveniles of the grouper, Epinephelus tauvina were subjected to enzymatic dissociation using 0.25 % trypsin solution, under aseptic conditions. The resultant cells were suspended in Leibovitz' L-15 medium supplemented with 20 % fetal bovine serum. The cells were subsequently seeded into 25 cm2 tissue culture flasks at a density of 106 ml-1 and incubated at 28 ± 2°C. Cells showed spreading and attachment to the culture flasks within 24 h and formed monolayers comprising of epithelioid as well as fibroblast-like cells within 20 days. A confluent monolayer filling the flask surface comprising predominantly fibroblastic cells was formed within 30 to 35 days. The cell monolayer was harvested for passage by trypsinisation, which formed successful monolayers in subsequent subcultures.Not Availabl

Not Available

Not AvailableA cell culture system was developed successfully from gill explants of the Malabar grouper, Epinephelus malabaricus. Gill tissue samples aseptically excised from healthy juveniles of E. malabaricus were explanted in Leibovitz’ L-15 medium supplemented with 0.07 M NaCl and 20% fetal bovine serum (FBS). A mixture of different types of cells emerged from the explants, and these cells were observed to spread and attach to the culture flasks from the second day onwards. Confluent monolayers comprising epithelioid as well as fibroblast-like cells were formed within ten days. The cells were found to grow well at 28 + 2°C. The cell monolayers were subcultured by trypsinization and seeded into new flasks, which produced confluent monolayers comprising predominantly epithelioid-like cells in subsequent passages.Not Availabl

Development of a Cell Culture System from Gill Explants of the Grouper, Epinephelus malabaricus (Bloch and Shneider)

A cell culture system was developed successfully from gill explants of the Malabar grouper, Epinephelus malabaricus. Gill tissue samples aseptically excised from healthy juveniles of E. malabaricus were explanted in Leibovitz’ L-15 medium supplemented with 0.07 M NaCl and 20% fetal bovine serum (FBS). A mixture of different types of cells emerged from the explants, and these cells were observed to spread and attach to the culture flasks from the second day onwards. Confluent monolayers comprising epithelioid as well as fibroblast-like cells were formed within ten days. The cells were found to grow well at 28 + 2°C. The cell monolayers were subcultured by trypsinization and seeded into new flasks, which produced confluent monolayers comprising predominantly epithelioid-like cells in subsequent passages

Insulin-like growth factor I binding in hepatocytes from human liver, human hepatoma, and normal, regenerating, and fetal rat liver.

Insulin-like growth factor-I (IGF-I) in human hepatoma cells (HEP-G2) has, in addition to its effect on cell growth, short-term metabolic effects acting through its own receptor. We have demonstrated that normal human hepatocytes, compared with HEP-G2 cells, have virtually no IGF-I binding sites. Because the rate of growth is the major difference between the hepatoma and the normal liver, we asked if normal liver might express IGF-I binding sites under physiologic growth conditions. Indeed, whereas adult rat hepatocytes have low IGF-I binding sites similar to those in human liver, hepatocytes from regenerating liver after 3 d subtotal hepatectomy have an approximately sixfold increase (P less than 0.005) and those from fetal rat liver a approximately 12-fold increase (P less than 0.005), to levels comparable to those in the HEP-G2 cells. The specificity of 125I IGF-I binding to its receptor was demonstrated by competition studies with monoclonal antibodies directed toward the IGF-I and the insulin receptors, with unlabeled IGF-I and insulin and by affinity labeling experiments. Thus, if IGF-I has any short-term metabolic functions in the adult human liver, it is not through interaction with its own receptor. Autocrine regulation by IGF-I of liver growth appears possible since IGF-I binding sites are expressed under pathological and physiological conditions of growth. The mechanism that couples these two phenomena remains to be elucidated