In utero detection of T7 phage after systemic administration to pregnant mice.

The phage is used as a scaffold to display recombinant libraries of peptides, which provides the means to rescue and amplify peptides that bind target macromolecules. Many reports showed that the T7 phage display method can be used to obtain a ligand-binding peptidefor tissue-targeted therapies in adult animals. In utero tissue targeting of fetal tissues may help in the correction of many genetic and metabolic diseases. Here we demonstrate the distribution and detection of T7 phage displaying the C-X7-C peptide library in mouse fetal tissues after systemic injection of T7 phage into pregnant mouse tail vein. T7 phage was recovered from fetal tissues 15 min after injection of T7 phage. Our results suggest that T7 phage may be a useful tool in selecting the tissue-specific ligand-binding peptide for fetal tissues. This approach may be helpful in designing in utero tissue-targeted therapies.

Induction of apoptosis in human lung cancer cells by curcumin.

Curcumin, a phenolic compound from the rhizome of the plant Curcuma longa has anti-inflammatory, antioxidant and anti-cancer activities. Although the precise mode of action of this compound is not yet elucidated, studies have shown that chemo-preventive action of curcumin might be due to its ability to induce apoptosis and to arrest cell cycle. This study investigated the cellular and molecular changes induced by curcumin leading to the induction of apoptosis in human lung cancer cell lines-A549 and H1299. A549 is p53 proficient and H1299 is p53 null mutant. The lung cancer cells were treated with curcumin (0-160 microM) for 12-72 h. Curcumin inhibited the growth of both the cell lines in a concentration dependent manner. Growth inhibition of H1299 cell lines was both time and concentration dependent. Curcumin induced apoptosis in both the lung cancer cell lines. A decrease in expression of p53, bcl-2, and bcl-X(L) was observed after 12 h exposure of 40 microM curcumin. Bak and Caspase genes remained unchanged up to 60 microM curcumin but showed decrease in expression levels at 80-160 microM. The data also suggest a p53 independent induction of apoptosis in lung cancer cells.

Purification and properties of cytosolic alanine aminotransferase from the liver of two freshwater fish, Clarias batrachus and Labeo rohita.

Cytosolic alanine aminotransferase (c-AAT) was purified up to 203- and 120-fold, from the liver of two freshwater teleosts Clarias batrachus (air-breathing, carnivorous) and Labeo rohita (water-breathing, herbivorous), respectively. The enzyme from both fish showed similar elution profiles on a DEAE-Sephacel ion exchange column. SDS-PAGE of purified enzymes revealed two subunits of 54 and 56 kDa, in both fish. The apparent Km values for l-alanine were 18.5+/-0.48 and 23.55+/-0.60 mM, whereas for 2-oxoglutarate the Km values were observed to be 0.29+/-0.023 and 0.33+/-0.028 mM for the enzyme from C. batrachus and L. rohita, respectively. With l-alanine as substrate, aminooxyacetic acid was found to act as a competitive inhibitor with KI values of 6.4 x 10(-4) and 3.4 x 10(-4) mM with c-AAT of C. batrachus and L. rohita, respectively. However, when 2-oxoglutarate was used as substrate, aminooxyacetic acid showed uncompetitive inhibition with similar KI values for purified c-AAT from both fish. Temperature and pH profiles of the enzyme did not show any marked differences between the two fish examined. These results suggest that liver c-AAT, isolated from these two fish species adapted to different modes of life, remain unaltered structurally. However, at the kinetic level, liver c-AAT from C. batrachus exhibits significantly higher affinity for the substrate l-alanine and decreased affinity for its metabolic inhibitor, in comparison to that of the enzyme purified from L. rohita. Such functional changes seem to be of physiological significance and also provide preliminary evidence for subtle changes in the enzyme as a mark of metabolic adaptation in the fish to different physiological demands.

Oxidative stress inactivates the human DNA mismatch repair system.

In the human DNA mismatch repair (MMR) system, hMSH2 forms the hMutSalpha and hMutSbeta complexes with hMSH6 and hMSH3, respectively, whereas hMLH1 and hPMS2 form the hMutLalpha heterodimer. These complexes, together with other components in the MMR system, correct single-base mismatches and small insertion/deletion loops that occur during DNA replication. Microsatellite instability (MSI) occurs when the loops in DNA microsatellites are not corrected because of a malfunctioning MMR system. Low-frequency MSI (MSI-L) is seen in some chronically inflamed tissues in the absence of genetic inactivation of the MMR system. We hypothesize that oxidative stress associated with chronic inflammation might damage protein components of the MMR system, leading to its functional inactivation. In this study, we demonstrate that noncytotoxic levels of H2O2 inactivate both single-base mismatch and loop repair activities of the MMR system in a dose-dependent fashion. On the basis of in vitro complementation assays using recombinant MMR proteins, we show that this inactivation is most likely due to oxidative damage to hMutSalpha, hMutSbeta, and hMutLalpha protein complexes. We speculate that inactivation of the MMR function in response to oxidative stress may be responsible for the MSI-L seen in nonneoplastic and cancer tissues associated with chronic inflammation.