Comparative study of two thioredoxin peroxidases from disk abalone (Haliotis discus discus): cloning, recombinant protein purification, characterization of antioxidant activities and expression analysis

Thioredoxin peroxidase (TPx), also named peroxiredoxin (Prx), is an important peroxidase, which can protect organisms against various oxidative stresses. Two TPxs were isolated from a disk abalone (Haliotis discus discus) cDNA library, named as AbTPx1 and AbTPx2, respectively. AbTPx1 and AbTPx2 consist of 1315 and 1045 bp full-length cDNA with 753 and 597 bp open reading frames encoding 251 and 199 amino acids, respectively. The TPx signature motif 1 (FYPLDFTFVCPTEI) and motif 2 (GEVCPA) were conserved in both AbTPx1 and AbTPx2 amino acid sequences. Purified recombinant abalone TPx fusion proteins catalyzed the reduction of H2O2 and butyl hydroperoxide in peroxidase assays. Furthermore, both AbTPx fusion proteins were shown to protect super-coiled DNA from damage by metal-catalyzed oxidation (MCO) in vitro. Escherichia coli cells transformed with AbTPx1 and AbTPx2 coding sequences in pMAL-c2x showed resistance to H2O2 at 0.8 mM concentration by in vivo H2O2 tolerance assay. AbTPx1 and AbTPx2 mRNA were constitutively expressed in gill, mantle, abductor muscle and digestive tract in a tissue specific manner. Additionally, both TPxs mRNA were up-regulated in gill and digestive tract tissues against H2O2 at 3h post injection. The results indicate that AbTPx1 and AbTPx2 gene expressions are induced by oxidative stress and their respective proteins function in the detoxification of different ROS molecules to maintain efficient antioxidant defense in disk abalone.     

Magnesium ion is an effective inhibitor of the binding of Escherichia coli to heparin

We investigated the effects of ions and temperature on the binding of E. coli to heparin using a chemiluminescence electrophoretic mobility shift assay. We found that magnesium ion is an effective inhibitor of the binding. The method can be readily applied to discover agents that can block the binding.     

Distribution of the Ussur Brown Katydid,Paratlanticus ussuriensis,in South Korea

This study was conducted to monitor the abundance and distribution of the ussur brown katydid, Paratlanticus ussuriensis in South Korea, and to gather basic information about potential outbreak areas of this species. P. ussuriensis samples were collected from April to July in 2009 and 2010 using the transect method at the city or gun level. P. ussuriensis were identified in 86 cities or guns, and eight guns were determined to be potential risk areas of P. ussuriensis outbreaks. The current distribution of P. ussuriensis is well matched with the distribution of broadleaf trees. Their distribution and population density are expected to increase due to the expanding distribution of Quercus spp., the major food source of P. ussuriensis.     

Atomic Layer Deposition of CdS Quantum Dots for Solid‐State Quantum Dot Sensitized Solar Cells

Functioning quantum dot (QD) sensitized solar cells have been fabricated using the vacuum deposition technique atomic layer deposition (ALD). Utilizing the incubation period of CdS growth by ALD on TiO₂, we are able to grow QDs of adjustable size which act as sensitizers for solid‐state QD‐sensitized solar cells (ssQDSSC). The size of QDs, studied with transmission electron microscopy (TEM), varied with the number of ALD cycles from 1‐10 nm. Photovoltaic devices with the QDs were fabricated and characterized using a ssQDSSC device architecture with 2,2',7,7'‐tetrakis‐(N,N‐di‐p methoxyphenylamine) 9,9'‐spirobifluorene (spiro‐OMeTAD) as the solid‐state hole conductor. The ALD approach described here can be applied to fabrication of quantum‐confined structures for a variety of applications, including solar electricity and solar fuels. Because ALD provides the ability to deposit many materials in very high aspect ratio substrates, this work introduces a strategy by which material and optical properties of QD sensitizers may be adjusted not only by the size of the particles but also in the future by the composition.     

Induction of Apoptotic Cell Death on Human Cervix Cancer HeLa cells by Extract from <Emphasis Type="Italic">Loranthus yadoriki</Emphasis>

Loranthus yadoriki, one of the Korean mistletoe species, has been already known for anti-viral effects, but the molecular basis that it caused apoptosis in cancer cells was not definitely revealed yet. The aim of this study was to estimate the mechanisms of apoptotic cell death of the extract from Loranthus yadoriki (named as ELY) in human cervix HeLa cells. We identified that ELY prevented the proliferation of HeLa cells between 50 and 300 μg/mL which did not affect non-cancerous HaCaT cells. In addition, ELY induced a morphological change and nucleus disruption as well as an accumulation of sub-G1 phase in HeLa cells. The mechanism study, by using western blot analysis, showed that the phosphorylation of Fas-associated death domain (FADD), Bim and Bak was up-regulated by ELY treatment. Furthermore, the expression of cytochrome c and Apaf-1 was increased by ELY treatment. In immunofluorescence staining, the increased intensity of cleaved caspase-3 and cleaved PARP was also observed under ELY treatment. Sequentially, the caspase cascade was activated by ELY from caspase-8 to caspase-3 and from caspase-9 to caspase-3, in both extrinsic and intrinsic pathways. The results of this study demonstrate that ELY has anti-cancer effects on human cervix cancer HeLa cells via caspase cascade in apoptotic signaling pathways.     

Lysine-Specific Demethylase 1 in Breast Cancer Cells Contributes to the Production of Endogenous Formaldehyde in the Metastatic Bone Cancer Pain Model of Rats

Background

Bone cancer pain seriously affects the quality of life of cancer patients. Our previous study found that endogenous formaldehyde was produced by cancer cells metastasized into bone marrows and played an important role in bone cancer pain. However, the mechanism of production of this endogenous formaldehyde by metastatic cancer cells was unknown in bone cancer pain rats. Lysine-specific demethylase 1 (LSD1) is one of the major enzymes catalyzing the production of formaldehyde. The expression of LSD1 and the concentration of formaldehyde were up-regulated in many high-risk tumors.

Objective

This study aimed to investigate whether LSD1 in metastasized MRMT-1 breast cancer cells in bone marrows participated in the production of endogenous formaldehyde in bone cancer pain rats.

Methodology/Principal Findings

Concentration of the endogenous formaldehyde was measured by high performance liquid chromatography (HPLC). Endogenous formaldehyde dramatically increased in cultured MRMT-1 breast cancer cells in vitro, in bone marrows and sera of bone cancer pain rats, in tumor tissues and sera of MRMT-1 subcutaneous vaccination model rats in vivo. Formaldehyde at a concentration as low as the above measured (3 mM) induced pain behaviors in normal rats. The expression of LSD1 which mainly located in nuclei of cancer cells significantly increased in bone marrows of bone cancer pain rats from 14 d to 21 d after inoculation. Furthermore, inhibition of LSD1 decreased the production of formaldehyde in MRMT-1 cells in vitro. Intraperitoneal injection of LSD1 inhibitor pargyline from 3 d to 14 d after inoculation of MRMT-1 cancer cells reduced bone cancer pain behaviors.

Conclusion

Our data in the present study, combing our previous report, suggested that in the endogenous formaldehyde-induced pain in bone cancer pain rats, LSD1 in metastasized cancer cells contributed to the production of the endogenous formaldehyde.