Syntheses of Paromamine and Its Related Compounds

Paromamine and its related compounds were synthesized by a modified Königs-Knorr reaction of 3,4,6-tri-O-acetyl-2-(2′,4′-dinitroanilno)-α-d-glucopyranosyl bromide with isopropylidene derivatives of 2-deoxystreptamine, streptamine and dihydroconduramine F–4. The condensed products were isolated as their poly N-acetyl derivatives and proved to have α-configuration by PMR spectroscopy in D₂O.     

A New Method for Estimation of the Mycelial Weight in Koji

A New method was devised for the estimation of the mycelial weight in rice-koji. In this method, the content of glucosamine in koji was used for the calculation of mycelial weight. The content of glucosamine in the mycelia of Aspergillus oryzae, koji, and rice was determined by a colorimetry after hydrolysis of these materials with sulfuric acid and purification of glucosamine fraction with a Dowex 50 W column. And the values of glucosamine were 114.5 mg/g in mycelia, 3.03 in the koji for amazake,* 1.34 in the koji for sake, and 0.0 in rice. The mycelial contents calculated from these data were 2.6% dry weight in amazake-koji and 1.2% in sake-koji.     

Production of Acetone and Butanol Using Immobilized Growing-cells of Clostridium acetobutylicum

The biosynthetic route for chloromonilicin, an antifungal substance from cherry rot fungus, was investigated using deuterium-labeled precursors. The incorporation of synthetic deuterium-labeled moniliphenone into chloromonilicin and into its xanthone precursor, 4-chloropinselin, was confirmed by ’H-NMR spectrometry.     

Isolation and Structure of Phytotoxic Compounds Produced by Phyllosticta sp.

In the course of phytopathological studies, it has been observed that phyllosticta sp. produces a toxic compound causing wilting and simultaneous dark coloration of the clover leaf. A toxin, herein refered to as phyllosinol (mp 76~77°C) was isolated in a crystalline state from the pure culture and it was proved to be the principal toxic metabolite of the fungus. Although the melting point of phyllosinol differed significantly from that reported for epoxydon (40~45°C), the structural evidence deduced from spectrometric and chemical methods indicates that phyllosinol is substantially identical with epoxydon even in stereo-isomeric considerations. In the red clover leaf test 10 ppm phyllosinol showed the wilting effect.     

An Archaeal Homolog of Proteasome Assembly Factor Functions as a Proteasome Activator

Assembly of the eukaryotic 20S proteasome is an ordered process involving several proteins operating as proteasome assembly factors including PAC1-PAC2 but archaeal 20S proteasome subunits can spontaneously assemble into an active cylindrical architecture. Recent bioinformatic analysis identified archaeal PAC1-PAC2 homologs PbaA and PbaB. However, it remains unclear whether such assembly factor-like proteins play an indispensable role in orchestration of proteasome subunits in archaea. We revealed that PbaB forms a homotetramer and exerts a dual function as an ATP-independent proteasome activator and a molecular chaperone through its tentacle-like C-terminal segments. Our findings provide insights into molecular evolution relationships between proteasome activators and assembly factors.     

Island-Model Genomic Selection for Long-Term Genetic Improvement of Autogamous Crops

Acceleration of genetic improvement of autogamous crops such as wheat and rice is necessary to increase cereal production in response to the global food crisis. Population and pedigree methods of breeding, which are based on inbred line selection, are used commonly in the genetic improvement of autogamous crops. These methods, however, produce a few novel combinations of genes in a breeding population. Recurrent selection promotes recombination among genes and produces novel combinations of genes in a breeding population, but it requires inaccurate single-plant evaluation for selection. Genomic selection (GS), which can predict genetic potential of individuals based on their marker genotype, might have high reliability of single-plant evaluation and might be effective in recurrent selection. To evaluate the efficiency of recurrent selection with GS, we conducted simulations using real marker genotype data of rice cultivars. Additionally, we introduced the concept of an “island model” inspired by evolutionary algorithms that might be useful to maintain genetic variation through the breeding process. We conducted GS simulations using real marker genotype data of rice cultivars to evaluate the efficiency of recurrent selection and the island model in an autogamous species. Results demonstrated the importance of producing novel combinations of genes through recurrent selection. An initial population derived from admixture of multiple bi-parental crosses showed larger genetic gains than a population derived from a single bi-parental cross in whole cycles, suggesting the importance of genetic variation in an initial population. The island-model GS better maintained genetic improvement in later generations than the other GS methods, suggesting that the island-model GS can utilize genetic variation in breeding and can retain alleles with small effects in the breeding population. The island-model GS will become a new breeding method that enhances the potential of genomic selection in autogamous crops, especially bringing long-term improvement.