Vitellogenin-derived fragment in embryos of Japanese flounder Paralichthys olivaceus with binding and bactericidal activities against an infectious bacterium via an interaction with saccharides.

Thirty- and 90-kDa proteins with binding ability to Edwardsiella tarda, a causative bacterium of Edwardsiellosis in fish, were purified from the embryo of Japanese flounder Paralichthys olivaceus. The proteins were isolated with affinity chromatography, in which the bacterium was used as a ligand and galactose, mannose, and ethylenediaminetetraacetic acid (EDTA) were used as elution agents, followed by gel filtration chromatography. N-terminal amino acid sequencing and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry (LC/Q-TOF-MS) analysis revealed that the 90-kDa protein was lipovitellin heavy-chain (LvH), which is one of the proteolytically cleaved products of maternal vitellogenin (Vg) and represents the main precursor of the egg yolk in teleosts, and the 30-kDa protein was an N-terminal bit of LvH. On the other hand, Vg in the serum of the mother fish did not bind to E. tarda. While the 90-kDa protein did not show anti-bacterial activity, the 30-kDa protein strongly exhibited activity toward E. tarda, with a minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) below 0.06 µM, suggesting that the latter protein plays an important role during embryogenesis in the flounder. This is the first report showing that Vg-derived products have monosaccharides-binding activity and a fragment derived from LvH exhibits bactericidal activity.

eIF4G-driven translation initiation of downstream ORFs in mammalian cells.

Comprehensive genome-wide analysis has revealed the presence of translational elements in the 3' untranslated regions (UTRs) of human transcripts. However, the mechanisms by which translation is initiated in 3' UTRs and the physiological function of their products remain unclear. This study showed that eIF4G drives the translation of various downstream open reading frames (dORFs) in 3' UTRs. The 3' UTR of GCH1, which encodes GTP cyclohydrolase 1, contains an internal ribosome entry site (IRES) that initiates the translation of dORFs. An in vitro reconstituted translation system showed that the IRES in the 3' UTR of GCH1 required eIF4G and conventional translation initiation factors, except eIF4E, for AUG-initiated translation of dORFs. The 3' UTR of GCH1-mediated translation was resistant to the mTOR inhibitor Torin 1, which inhibits cap-dependent initiation by increasing eIF4E-unbound eIF4G. eIF4G was also required for the activity of various elements, including polyU and poliovirus type 2, a short element thought to recruit ribosomes by base-pairing with 18S rRNA. These findings indicate that eIF4G mediates translation initiation of various ORFs in mammalian cells, suggesting that the 3' UTRs of mRNAs may encode various products.

Asymmetric Michael Reaction of α-CF3 Thioester and α,ß-Unsaturated Aldehyde Catalyzed by Diphenylprolinol Silyl Ether.

Asymmetric Michael reaction of α-CF3 thioester and α,ß-unsaturated aldehyde is catalyzed by diphenylprolinol silyl ether to afford the trifluoromethyl substituted Michael product with excellent enantioselectivity. Although the Michael products were generated as a mixture of syn- and anti-isomers, they can be transformed to single isomers of other useful compounds, such as lactone, lactam, piperidine, dihydropyran containing trifluoromethyl groups, or fluoro substituents.

The role of LIM and SH3 protein-1 in bladder cancer metastasis.

The LIM and SH3 protein-1 (LASP-1) is a multi-domain protein that is involved in several malignant cancers. The role of LASP-1 in malignant phenotypes including high invasive properties and unrestricted cell proliferation, remain to be elucidated. The present study reported the association of LASP-1 expression with bladder cancer malignancy and its role in cancer cell invasion and proliferation. The immunohistochemical analysis of the expression status of LASP-1 in radical cystectomy specimens from invasive bladder cancer patients revealed that the LASP-1-positive patients demonstrated a decreased survival rate compared with the LASP-1-negative patients. The expression level of LASP-1 was increased in invasive bladder cancer cell lines compared with the non-invasive bladder cancer cell lines. Invasive cancer cells form invadopodia, the filamentous actin-based membrane protrusions that are essential in cancer cell invasion. Knockdown of LASP-1 reduced the ability to form invadopodia, resulting in decreased invasive capacity of the LASP-1 knockdown cells. In addition, knockdown of LASP-1 reduced cell proliferation. These results suggest that LASP-1 is important in invadopodia formation and cell proliferation of bladder cancer cells, promoting the malignant properties and resulting in poor-prognosis.

A mechanism for evasion of CTL immunity by altered O-glycosylation of HLA class I.

Anti-tumour immunity by cytotoxic T-lymphocytes (CTLs) is essential to suppress tumour progression. Cancer cells that evade CTL immunity proliferate in the host, promoting metastasis, but mechanisms underlying this capacity remain unknown. Here we report that bladder cancer cells metastasized to lymph nodes evade CTL immunity by a new mechanism via altered glycosylation. CTLs normally recognize and kill cancer cells presenting antigenic peptides on human leukocyte antigen (HLA) class I. We show bladder cancer cells expressing the O-glycan processing enzyme, core2 ß-1,6-N-acetylglucosaminyltransferase (C2GnT) exhibit HLA class I O-glycan modified with poly-N-acetyllactosamine and are highly susceptible to CTL. In those cells, poly-N-acetyllactosamine on HLA class I O-glycan binds galectin-3 to form a cell-surface molecular lattice, enabling efficient cell-surface retention of HLA class I. In contrast, bladder cancer cells in which C2GnT is downregulated show decreased levels of poly-N-acetyllactosamine on HLA class I O-glycans, attenuating lattice formation and reducing the cell-surface half-life of HLA class I. These tumour cells present antigenic peptides less efficiently, thereby evading CTL lysis and facilitating metastasis.

Tea polyphenols ameliorate fat storage induced by high-fat diet in Drosophila melanogaster.

BACKGROUND: Polyphenols in tea are considered beneficial to human health. However, many such claims of their bioactivity still require in vitro and in vivo evidence. RESULTS: Using Drosophila melanogaster as a model multicellular organism, we assess the fat accumulation-suppressing effects of theaflavin (TF), a tea polyphenol; epitheaflagallin (ETG), which has an unknown function; and epigallocatechin gallate (EGCg), a prominent component of green tea. Dietary TF reduced the malondialdehyde accumulation related to a high-fat diet in adult flies. Other physiological and genetic responses induced by the high-fat diet, such as lipid accumulation in the fat body and expression of lipid metabolism-related genes, were ameliorated by the addition of TF, ETG, and EGCg, in some cases approaching respective levels without high-fat diet exposure. Continuous ingestion of the three polyphenols resulted in a shortened lifespan. CONCLUSION: We provide evidence in Drosophila that tea polyphenols have a fat accumulation-suppressing effect that has received recent attention. We also suggest that tea polyphenols can provide different desirable biological activities depending on their composition and the presence or absence of other chemical components.

Computational analysis of stop codon readthrough in D.melanogaster.

MOTIVATION: Readthrough is an unusual process in which a stop codon is misread or skipped. Recently it has been shown that some translation is regulated by the readthrough reactions although the complete mechanism is not clear. Therefore, the discovery of 'readthrough genes' is important for further investigation of their cellular roles, which may provide additional insights into the mechanism of translational regulation. RESULTS: We constructed a system that lists candidates of readthrough genes based on the existence of a 'protein motif' at the 3' untranslated region (UTR). Using this system, we extracted 85 candidates from 4082 nucleic acid sequences of Drosophila melanogaster in GenBank database. The sequences of these candidates had a slightly more stable secondary structure and different base preferences compared to the non-candidates. As these features are known to have an effect on readthrough events, we would like to suggest that these candidates contain actual readthrough genes. AVAILABILITY: Source code of the system is available upon request.