Perenniporiol derivatives six triterpenoids from the cultured mycelia of Perenniporia ochroleuca

Six new triterpenoids, (26S)-26-O-methylperenniporiol, (26S)-3-acetyl-26-O-methylperenniporiol, perenniporiol, 3-acetylperenniporiol, (26S-15-deacetoxy-7,11-dihydro-26-O-methylperenniporiol and 15-deacetoxy-7,11-dihydroperenniporiol were isolated from the cultured mycelia of Perenniporia ochroleuca. The structures of the first two compounds were determined using spectroscopic and X-ray analyses, and the structures of the other compounds were elucidated by spectroscopic data.     

Catalytically inactive cyclooxygenase 2 and absence of prostaglandin E2 biosynthesis in murine peritoneal macrophages following in vivo phagocytosis of heat-killed Mycobacterium bovis bacillus Calmette-Guérin

Over 25 years ago, it was observed that peritoneal macrophages (Mphi) isolated from mice given heat-killed Mycobacterium bovis bacillus Calmette-Guérin (HK-BCG) i.p. did not release PGE(2). However, when peritoneal Mphi from untreated mice are treated with HK-BCG in vitro, cyclooxygenase 2 (COX-2), a rate-limiting enzyme for PGE(2) biosynthesis, is expressed and the release of PGE(2) is increased. The present study of peritoneal Mphi obtained from C57BL/6 mice and treated either in vitro or in vivo with HK-BCG was undertaken to further characterize the cellular responses that result in suppression of PGE(2) release. The results indicate that Mphi treated with HK-BCG in vivo express constitutive COX-1 and inducible COX-2 that are catalytically inactive, are localized subcellularly in the cytoplasm, and are not associated with the nuclear envelope (NE). In contrast, Mphi treated in vitro express catalytically active COX-1 and COX-2 that are localized in the NE and diffusely in the cytoplasm. Thus, for local Mphi activated in vivo by HK-BCG, the results indicate that COX-1 and COX-2 dissociated from the NE are catalytically inactive, which accounts for the lack of PGE(2) production by local Mphi activated in vivo with HK-BCG. Our studies further indicate that the formation of catalytically inactive COX-2 is associated with in vivo phagocytosis of HK-BCG, and is not dependent on extracellular mediators produced by in vivo HK-BCG treatment. This attenuation of PGE(2) production may enhance Mphi-mediated innate and Th1-acquired immune responses against intracellular infections which are suppressed by PGE(2).     

Theanine, r-glutamylethylamide, increases neurotransmission concentrations and neurotrophin mRNA levels in the brain during lactation

Theanine (r-glutamylethylamide) is one of the major amino acid components in green tea. Recent studies suggest that theanine affects neurotransmission, especially inhibitory neurotransmission. In this study, we investigated whether theanine affects brain development in infant rats, because inhibitory neurotransmission is required for mature brain function. Mother rats were fed theanine ad libitum after confinement. The body weight gain rate of infants was not different from control infants. We detected theanine in the infant serum and measured neurotransmitter concentration and nerve growth factor (NGF) mRNA level in the infant rat brain. Some neurotransmitters, including dopamine, serotonin, glycine and GABA concentration, increased in the infant brain and NGF mRNA level increased in the cerebral cortex and hippocampus. However, these differences were lost by the end of nerve maturity. These results suggest that theanine enhanced synthesis of nerve growth factor and neurotransmitters during a nerve maturing period and promoted central nerve system maturation (CNS). Thus, theanine accelerated maturation. In conclusion, theanine may assist in healthy brain function development.     

Involvement of up-regulated Necl-5/Tage4/PVR/CD155 in the loss of contact inhibition in transformed NIH3T3 cells

Normal cells show contact inhibition of cell movement and proliferation, but this is lost following transformation. We found that Necl-5, originally identified as a poliovirus receptor and up-regulated in many cancer cells, enhances growth factor-induced cell movement and proliferation. We showed that when cells contact other cells, Necl-5 interacts in trans with nectin-3 and is removed by endocytosis from the cell surface, resulting in a reduction of cell movement and proliferation. We show here that up-regulation of the gene encoding Necl-5 by the oncogene V12-Ki-Ras causes enhanced cell movement and proliferation. Upon cell-cell contact, de novo synthesis of Necl-5 exceeds the rate of Necl-5 endocytosis, eventually resulting in a net increase in the amount of Necl-5 at the cell surface. In addition, expression of the gene encoding nectin-3 is markedly reduced in transformed cells. Thus, up-regulation of Necl-5 following transformation contributes to the loss of contact inhibition in transformed cells.     

Unscheduled overexpression of human WAPL promotes chromosomal instability

Previously, we have isolated and characterized a novel human gene termed human WAPL that has the characteristics of an oncogene in uterine cervical cancer. WAPL is inducible by human papillomavirus (HPV) E6 and E7 oncoproteins. On the other hand, recent studies have revealed that WAPL regulates sister chromatid resolution by controlling the association of cohesin and chromatin. However, the effects of WAPL overexpression on cervical carcinogenesis are still unclear. Here, we show that WAPL overexpression induces generation of multinucleated cells. In addition, WAPL-overexpressing cells demonstrated increases in chromatid breaks in comparison with control cells. These results were obtained even in HPV-negative cell lines. High frequent premature sister separation by disregulation of cohesin may lead to these results. Thus, our study suggests that unscheduled overexpression of WAPL disturbs mitosis and cytokinesis, and contributes to tumor progression by induction of chromosomal instability (CIN).     

Proteomic study on X-irradiation-responsive proteins and ageing: search for responsible proteins for radiation adaptive response

We investigated high- or low-dose irradiation-responsive proteins using proteomics on two-dimensional (2D) PAGE, and the effects of ageing on cell responses to radiation in variously aged rat astrocytes. After 5 Gy irradiation, the relative abundance of peroxiredoxin 2, an antioxidant enzyme, and latexin, an inhibitor of carboxypeptidase, increased. The induction of these proteins was suppressed by ageing, suggesting that the response to high-dose radiation decreased with ageing. The relative abundance of elongation factor 2 (EF-2) fragment increased 3 h and reduced 24 h after 0.1 Gy irradiation. Temporal enhancement of the EF-2 fragment due to low-dose irradiation was suppressed by ageing. Since radiation adaptive response in cultured astrocytes was observed 3 h but not 24 h after 0.1 Gy irradiation and suppressed by ageing as previously reported, alteration of the EF-2 fragment corresponded to the radiation adaptive response. We also examined phospho-protein profiles, resulting in the relative abundance of phospho-EF-1beta and phospho-beta-actin being altered by 0.1 Gy irradiation; however, ageing did not affect the alteration of phospho-EF-1beta and phospho-beta-actin, unlike the EF-2 fragment. The results suggested that the EF-2 fragment was a possible candidate for the protein responsible for the radiation adaptive response in cultured astrocytes.     

Brownian motion, fluctuation and life

The measurements of dynamic behaviors of biomolecules in relation to their functions have been allowed using single molecule measurements. Thermal Brownian motion causes random step motion of motor proteins and structural fluctuation of protein molecules between multiple states. In hierarchic structure of life, the fluctuation is modulated. Random fluctuation is biased to directional motion and reactions as a result of interaction of proteins. The fluctuation of kinetic state of signaling proteins results in polarization and localization of cells. A recognition process in brain is also explained by the equation analogous to biochemical reaction at the molecular level. Thus dynamic processes originated from thermal motion may play an important role in activation processes in life.     

Novel mating type-dependent transcripts at the mating type locus in Magnaporthe oryzae

The mating type locus (MAT1) of Magnaporthe oryzae has similar structural organization to MAT in other ascomycetes and encodes the mating type genes MAT1-1-1 with an alpha-box motif and MAT1-2-1 with an HMG-box motif in the MAT1-1 and MAT1-2 idiomorphs, respectively. Sequence and expression analyses of the MAT1 locus indicated a second open reading frame (ORF), MAT1-1-2, in the MAT1-1 idiomorph, and novel mating-type dependent ORFs (MAT1-1-3 and MAT1-2-2) at the locus. The MAT1-1-3 ORF initiated within the MAT1-1 idiomorph while the MAT1-2-2 ORF initiated at the border of the MAT1-2 idiomorph with both ORFs sharing most of their reading frames in the MAT1 flanking region. This suggests that the encoded proteins (MAT1-1-3 and MAT1-2-2) should be similar in their primary structures but can be distinguished by distinct N-termini with amino acids of 1 and 32, respectively, in each mating type. A CT dinucleotide repeat, (CT)n, present in the upstream region of MAT1-1-3, was polymorphic among the isolates.