Fatty acid and lipid composition in mycelia from submerged or surface culture of Streptomyces viridochromogenes

Abstract Streptomyces viridochromogenes was grown both as submerged and surface culture. Mycelia from these cultures were analysed for the composition of lipids and fatty acids. An increase in ornithinolipid content according to incubation time was observed. The addition of phosphate inhibited the ornithinolipid synthesis. A mutant strain with bald phenotype did not exhibit the phosphate inhibition. At the same time, the mutant strain had a higher content of 12-methyltetradecanoic acid.     

The interaction of DNA mismatch repair proteins with human exonuclease I.

Exonucleolytic degradation of DNA is an essential part of many DNA metabolic processes including DNA mismatch repair (MMR) and recombination. Human exonuclease I (hExoI) is a member of a family of conserved 5' --> 3' exonucleases, which are implicated in these processes by genetic studies. Here, we demonstrate that hExoI binds strongly to hMLH1, and we describe interaction regions between hExoI and the MMR proteins hMSH2, hMSH3, and hMLH1. In addition, hExoI forms an immunoprecipitable complex with hMLH1/hPMS2 in vivo. The study of interaction regions suggests a biochemical mechanism of the involvement of hExoI as a downstream effector in MMR and/or DNA recombination.     

Sprouty1 and Sprouty2 limit both the size of the otic placode and hindbrain Wnt8a by antagonizing FGF signaling

Multiple signaling molecules, including Fibroblast Growth Factor (FGF) and Wnt, induce two patches of ectoderm on either side of the hindbrain to form the progenitor cell population for the inner ear, or otic placode. Here we report that in Spry1, Spry2 compound mutant embryos (Spry1^−/−; Spry2^−/− embryos), the otic placode is increased in size. We demonstrate that the otic placode is larger due to the recruitment of cells, normally destined to become cranial epidermis, into the otic domain. The enlargement of the otic placode observed in Spry1^−/−; Spry2^−/− embryos is preceded by an expansion of a Wnt8a expression domain in the adjacent hindbrain. We demonstrate that both the enlargement of the otic placode and the expansion of the Wnt8a expression domain can be rescued in Spry1^−/−; Spry2^−/− embryos by reducing the gene dosage of Fgf10. Our results define a FGF-responsive window during which cells can be continually recruited into the otic domain and uncover SPRY regulation of the size of a putative Wnt inductive center.     

Role of two adaptor molecules SLP-76 and LAT in the PI3K signaling pathway in activated T cells

Previously, we identified p85, a subunit of PI3K, as one of the molecules that interacts with the N-terminal region of Src homology 2 domain-containing leukocyte protein of 76 kDa (SLP-76). We also demonstrated that tyrosine phosphorylation either at the 113 and/or 128 position is sufficient for the association of SLP-76 with the Src homology 2 domain near the N terminus of p85. The present study further examines the role of the association of these two molecules on the activation of PI3K signaling cascade. Experiments were done to determine the role of SLP-76, either wild-type, tyrosine mutants, or membrane-targeted forms of various SLP-76 constructs, on the membrane localization and phosphorylation of Akt, which is an event downstream of PI3K activation. Reconstitution studies with these various SLP-76 constructs in a Jurkat variant cell line that lacks SLP-76 or linker for activation of T cells (LAT) show that the activation of PI3K pathway following TCR ligation requires both SLP-76 and LAT adaptor proteins. The results suggest that SLP-76 associates with p85 after T cell activation and that LAT recruits this complex to the membrane, leading to Akt activation.     

A methylene chloride fraction of Saururus chinensis induces apoptosis through the activation of caspase-3 in prostate and breast cancer cells

The aerial parts of Saururus chinensis (SC) have been used for the treatment of edema, fever, jaundice, and inflammatory diseases in Korean folk medicine for centuries. However, the mechanism by which SC exerts these anti-tumorigenic activities in human prostate and breast cancer cells has not yet been fully understood. In this study, we report on the methylene chloride fraction from SC exerting cytotoxicity against prostate and breast cancer cells in a dose-dependent manner. Specifically, SC exerted the most potent cytotoxicity in LNCaP and MCF-7 cells. SC was shown to down-regulate various angiogenetic (VEGF), proliferative (Cyclin D₁), anti-apoptotic (Bcl-2) gene products in these cells. SC also increased the number of annexin V-positive apoptotic bodies and the sub-G1 DNA contents of the cell cycle undergoing apoptosis through caspase-3 activation in both LNCaP and MCF-7 cells. We further confirmed that caspase-3 plays an important role in SC-induced apoptosis in LNCaP and MCF-7 cells through the use of the caspase-3 inhibitor. Moreover, we observed that SC potentiated paclitaxel-induced apoptosis in MCF-7 cells and sauchinone is a major active constituent of SC, which could induce apoptosis in the cells. Taken together, our data provide the evidence that SC induces apoptosis depending on caspase-3 activation and overcomes the natural biological resistance to chemotherapy found in human prostate and breast cancer cells.     

Separation and simultaneous detection of anticancer drugs in a microfluidic device with an amperometric biosensor

A simple and highly sensitive method for simultaneous detection of anticancer drugs is developed by integrating the preconcentration and separation steps in a microfluidic device with an amperometric biosensor. An amperometric detection with dsDNA and cardiolipin modified screen printed electrodes are used for the detection of anticancer drugs at the end of separation channel. The preconcentration capacity is enhanced thoroughly using field amplified sample stacking and field amplified sample injection techniques. The experimental parameters affecting the analytical performances, such as pH, temperature, buffer concentration, water plug length, and detection potential are optimized. A reproducible response is observed during multiple injections of samples with a RSD <5%. The calibration plots are linear with the correlation coefficient between 0.9913 and 0.9982 over the range of 2-60 pM. The detection limits of four drugs are determined to be between 1.2 (± 0.05) and 5.5 (± 0.3) fM. The applicability of the device to the direct analysis of anticancer drugs is successfully demonstrated in a real spiked urine sample. Device was also examined for interference effect of common chemicals present in real samples.     

Regulation of sperm-specific proteins by IFE-1, a germline-specific homolog of eIF4E,in <Emphasis Type="Italic">C. elegans</Emphasis>

IFE-1 is one of the five C. elegans homologs of eIF4E, which is the mRNA 5′ cap-binding component of the translation initiation complex eIF4F. Depletion of IFE-1 causes defects in sperm, suggesting that IFE-1 regulates a subset of genes required for sperm functions. To further understand the molecular function of IFE-1, proteomic analysis was performed to search for sperm proteins that are downregulated in ife-1(ok1978); fem-3(q20) mutants relative to the fem-3(q20) control. The fem-3(q20) mutant background was used because it only produces sperm at restrictive temperature. Total worm proteins were subjected to 2D-DIGE, and differentially expressed protein spots were further identified by MALDI-TOF mass spectrometry. Among the identified proteins, GSP-3 and Major Sperm Proteins (MSPs) were found to be significantly down-regulated in the ife-1(ok1978) mutant. Moreover, RNAi of gsp-3 caused an ife-1-like phenotype. These results suggest that IFE-1 is required for efficient expression of some sperm-specific proteins, and the fertilization defect of ife-1 mutant is caused mainly by a reduced level of GSP-3.     

Wild ginseng attenuates anxiety- and depression-like behaviors during morphine withdrawal

The purpose of this study was to evaluate whether wild ginseng (WG) administration could attenuate anxiety- and depression-like behaviors and expression of corticotrophin-releasing factor (CRF) and neuropeptide Y (NPY) following withdrawal from repeated morphine administration in rats. Male rats were administered daily doses of WG (50, 100, or 200 mg/kg, i.p.) for 5 days, 30 min before morphine injection (40 mg/kg, s.c). The anxiety- and depression-like behavioral responses were measured 72 h after the last morphine injection using an elevated plus maze (EPM) and forced swimming test (FST), respectively. Changes in hypothalamic CRF and NPY expressions were also examined by analyzing their immunoreactivities in the hypothalamus. Daily administration of WG significantly reduced anxiety-and depression-like behavior, and elicited the suppression of CRF expression and the stimulation of NPY expression in the hypothalamus. Our results demonstrated that WG extract might be effective at inhibiting the anxiety and depression responses due to morphine withdrawal by possibly modulating the hypothalamus CRF and NPY systems. Furthermore, these findings imply that WG extract can be used for developing new medication to cure or alleviate morphine withdrawal symptoms and to prevent relapses of morphine use.