Molecular size of the diapause hormone of the silkworm Bombyx mori

The diapause hormone (DH) responsible for arrested development of the silkworm Bombix mori consists of two active principles of peptide (A and B). Since both hormones form aggregates in aqueous phases, the molecular weights were determined by gel permeation chromatography of Merckogel OR 6000 using methanol-dichloromethane mixture as the developing agent. Gramicidins and modified peptides soluble in the organic solvents were used as the standard markers for the molecular weight measurements of the hormones. The molecular weights of DH-A and -B are estimated to be 3300 +/- 400 and 2000 +/- 200, respectively.

Structure of wye (Yt base) and wyosine (Yt) from Torulopsis utilis phenylalanine transfer ribonucleic acid

A fluorescent base wye (Yt base) was isolated from Torulopsis utilis tRNAPhe. The structure was established as 4,9-dihydro-4,6-dimethyl-9-oxo-1H-imidazo[1,2-alpha]purine based on ultraviolet (uv), nuclear magnetic resonance (NMR), and mass spectra, and by direct comparison with synthetic material. The nucleoside, wyosine (Yt), was isolated from purified tRNAPhe by enzymatic degradations followed by column and thin-layer chromatographies. The structure of wyosine is proposed as 3-ribofuranosyl-4,9-dihydro-4,6-dimethyl-9-oxo-1H-imidazol[1,2-alpha]purine (the ribosyl group is attached to the N-9 position of guanine nucleus) on the basis of comparison with model compounds.

[An epidemiologic study on vibration hazards among workers at the state forests in Kyushu (author's transl)]

There are only very few reports of epidemiologic analysis on vibration hazards among the workers at the state forests of Japan since 1970. It was necessary to perform investigations on the state of vibration hazards anew, through some labor hygienic policies on the prevention of the hazards, such as regulation of the time of using vibrating tools, had been executed to some extent since 1970. From the data of physical check-ups of 861 chain saw users of 24 District Forestry Offices in Kumamoto, Miyazaki and Kagoshima Prefectures in the south of Kyushu, the transition of vibration hazards was studied by using the incidence and prevalence of Raynaud's phenomenon and paresthesia of the fingers as indices. From the yearly transition of the hazards, a tendency was observed of increasing patients with vibration syndrome during the period from 1962 to 1970 when countermeasures on vibration hazards were not sufficient. However, since 1970 the occurrence of Raynaud's Phenomenon has shown a tendency to decrease among the workers with short history of using chain saw and the occurrence of paresthesia of the fingers as indices. From the yearly transition of the hazards, a tendency was observed of increasing patients with vibration syndrome during the period from 1962 to 1970 when countermeasures on vibration hazards were not sufficient. However, since 1970 the occurrence of Raynaud's Phenomenon has shown a tendency to decrease among the workers with short history of using chain saw and the occurrence of paresthesia of the fingers to increase among those with long history. The results are suggestive of making clear the pathophysiology of vibration hazards.

Spectral characteristics of the bioluminescence induced in the marine fish, Porichthys notatus by Cypridina (ostracod) luciferin

Specimens of Porichthys notatus, which are naturally luminous along the coast of California, are non-luminous in Puget Sound. However, luminescence capability may be induced in the adult Puget Sound Porichthys by the administration of purified Cypridina (ostracod) luciferin, synthetic Cypridina luciferin, or Cypridina organisms. The bioluminescence emission spectra produced by the Puget Sound fish following induction is similar, if not identical, to that of the naturally luminous Porichthys notatus from California waters (maxima: 485 and 507 nm).

A new flavin enzyme catalyzing the reduction of dihydrodipicolinate in sporulating Bacillus subtilis. II. Kinetics and regulatory function

Dihydrodipicolinate reductase in Bacillus subtilis PCI 219 had FMN as a prosthetic group, and the hydrogen transfer pathway is considered to be NADPH yields FMN yields dihydrodipicolinate. Linewaver-Burk plots of the reciprocal of the activity against the reciprocal of the concentration of either of the two substrates, dihydrodipocolinate and NADPH, are consistent with a reaction mechanism involving interconversion of two free forms of the enzyme by the two substrates. The Km values obtained from the secondary plots are 0.77 mM for dihydrodipicolinate and 72 muM for NADPH. Inhibition by dipicolinate is competitive with NADPH and noncompetitive with dihydrodipicolinate, and shows positive cooperativity. The possible metabolic role of the reductase in sporulating Bacillus subtilis is discussed in connection with regulation of the biosyntheses of dipicolinate and diaminopimelate.