Early-Stage Induction of SWI/SNF Mutations during Esophageal Squamous Cell Carcinogenesis

The SWI/SNF chromatin remodeling complex is frequently inactivated by somatic mutations of its various components in various types of cancers, and also by aberrant DNA methylation. However, its somatic mutations and aberrant methylation in esophageal squamous cell carcinomas (ESCCs) have not been fully analyzed. In this study, we aimed to clarify in ESCC, what components of the SWI/SNF complex have somatic mutations and aberrant methylation, and when somatic mutations of the SWI/SNF complex occur. Deep sequencing of components of the SWI/SNF complex using a bench-top next generation sequencer revealed that eight of 92 ESCCs (8.7%) had 11 somatic mutations of 7 genes, ARID1A, ARID2, ATRX, PBRM1, SMARCA4, SMARCAL1, and SMARCC1. The SMARCA4 mutations were located in the Forkhead (85Ser>Leu) and SNF2 family N-terminal (882Glu>Lys) domains. The PBRM1 mutations were located in a bromodomain (80Asn>Ser) and an HMG-box domain (1,377Glu>Lys). For most mutations, their mutant allele frequency was 31–77% (mean 61%) of the fraction of cancer cells in the same samples, indicating that most of the cancer cells in individual ESCC samples had the SWI/SNF mutations on one allele, when present. In addition, a BeadChip array analysis revealed that a component of the SWI/SNF complex, ACTL6B, had aberrant methylation at its promoter CpG island in 18 of 52 ESCCs (34.6%). These results showed that genetic and epigenetic alterations of the SWI/SNF complex are present in ESCCs, and suggested that genetic alterations are induced at an early stage of esophageal squamous cell carcinogenesis.     

Effect of temperature on the development of the West Indian sweet potato weevil, <Emphasis Type="Italic">Euscepes postfasciatus</Emphasis> (Fairmaire) (Coleoptera: Curculionidae) on an artificial diet

The relationship between temperature and the development of the West Indian sweet potato weevil, Euscepes postfasciatus, on an artificial larval diet containing powdered sweet potato root, was examined at different fixed temperatures from 22 to 31°C. The developmental periods for egg, larvae, and pupae stages shortened in correlation with increased temperature. The thermal constant was 769.2 degree-days and the developmental zero for female and male was 11.1 and 11.7°C, respectively. Although we can rear this weevil at temperatures ranging from 22 to 31°C, rearing temperatures should be kept between 25 and 28°C because the developmental stages were too long at 22°C and the larval period was delayed at 31°C. The basis for these developmental data will be a useful key factor in designing a plan to eradicate the weevil by using a mass-rearing system and SIT.     

Classification of Proteases in Antarctic Krill

The species of endogenous proteases in Antarctic krill, Euphausia superba, were investigated using the homogenate of krill and the active fractions after gel filtration of the homogenate as to the following criteria: Substrate specificity (benzyloxycarbonyl (Z)-Phe-Ala, Z-Glu-Tyr, hippuryl-Arg, hippuryl-Phe, benzoyl Arg-p-nitroanilide, Leu-p-nitroanilide, ¹⁴C-hemoglobin), sensitivity to protease inhibitors (diisopropyl fluorophosphate, iodoacetamide, EDTA, soybean trypsin inhibitor and pepstatin), molecular weight and isoelectric point.

From the experimental results, we found that the carboxypeptidase A and B, aminopeptidase, trypsin and cathepsin A types of proteases were present in krill.     

Studies on the Glucanase of Sclerotinia Libertiana

Preparations of glucan obtained from baker’s yeast and sclerotia of Sclerotinia Libertiana were found to be completely hydrolysed by enzymes of the Sclerotinia fungus. Some differences in the molecular structure of the glucans were found upon examination of the modes of degradation by the successive action of Rhizopus- and Sclerotinia enzyme preparations of which the former had only a partial hydrolytic effect.

The dissolution of glucan in intact cells of yeast, that could be estimated from the rate of autolysis of the cells, was proved to be insignificant on the action of glucanase alone in the Sclerotinia enzyme solution. The combined action of glucanase with lipolytic enzyme in the fungus enzyme solution are shown to promote the solubilization of intact yeasts and sclerotium cells.     

13C-NMR Analysis of Hydroxy-proline Arabinosides from Nicotiana tabacum

The vanillin dehydrogenase gene (ligV), which conferred the ability to transform vanillin into vanillate on Escherichia coli, was isolated from Sphingomonas paucimobilis SYK-6. The ligV gene consists of a 1,440-bp open reading frame encoding a polypeptide with a molecular mass of 50,301 Da. The deduced amino acid sequence of ligV showed about 50% identity with the known vanillin dehydrogenases of Pseudomonas vanillin degraders. The gene product of ligV (LigV) produced in E. coli preferred NAD⁺ to NADP⁺ and exhibited a broad substrate preference, including vanillin, benzaldehyde, protocatechualdehyde, m-anisaldehyde, and p-hydroxybenzaldehyde, but the activity toward syringaldehyde was less than 5% of that toward vanillin. Insertional inactivation of ligV in SYK-6 indicated that ligV is essential for normal growth on vanillin. On the other hand, growth on syringaldehyde was only slightly affected by ligV disruption, indicating the presence of a syringaldehyde dehydrogenase gene or genes in SYK-6.     

Repression of Pyruvate Kinase in Candida utilis and Rat Liver by Sclerin through Energy Charge

Though sclerin (SCL) only slightly inhibited the activity of pyruvate kinase (PK) in crude extract of Candida utilis, markedly repressed the level of that in the growing cells in a glucose medium. The repression of PK was largely recovered by 2,4-dinitrophenol (DNP), and SCL rather raised the level in the cells growing on gluconate.

SCL also slightly inhibited the activity of a partially purified PK from rat liver, and, when orally administered, or incubated with the liver slices, obviously lowered the level of PK in the liver and liver slices. The effect of SCL in the liver slices was reversed by DNP. SCL stimulated the oxidative phosphorylation in mitochondria prepared from the fresh liver, and served to maintain the activity in the liver slices during incubation.

Both activity of PK from Candida utilis and rat liver was remarkably inhibited by adenylate energy charge in vitro.

It is concluded that SCL represses the level of PK in these cells and tissues through a high energy charge by stimulating the oxidative phosphorylation.