S. Aaronson

A new assay method for biotin in blood, serum, urine, and tissues

Abstract A new microbiological assay of biotin in blood, serum, urine, liver and brain tissue, using the protozoan Ochromonas danica , is described. Results are given for 12 normal subjects and 10 histological normal liver and brain specimens obtained at post mortem.

O-Methylthreonine, a New Bleaching Agent for Euglena gracilis

SUMMARY: O-Methylthreonine (OM) inhibits multiplication and photosynthetic pigment synthesis in Euglena gracilis and Ochromonas danica; it does not inhibit Chlamydomonas reinhardi or Rhodopseudomonas palustris. Inhibition of multiplication and pigment synthesis may be prevented by l-isoleucine. OM also causes the permanent loss of chlorophyll and appreciable loss of carotenoids in E. gracilis and this may be prevented by l-isoleucine, α-aminobutyric acid, α-ketobutyric acid, l-threonine, l-homoserine, or l-methionine. α-Ketobutyric acid is most effective on a molar basis and is therefore postulated to be the target of OM inhibition. Isoleucine plays a role in the biosynthesis of photosynthetic pigments and lipids in Euglena gracilis, for the incorporation of 14C-l-isoleucine radioactivity into both the pigments and lipids is markedly diminished by bleaching agents which prevent pigment synthesis without affecting multiplication, i.e. O-methylthreonine or streptomycin. When pigment synthesis is blocked amino acids accumulate in the culture supernate.

General considerations in the use of microorganisms in screening antitumor agents.

The prophets mantel is easily transformed into a strait jacket or dunce cap. As microbiologists rather detached from clinical urgencies, we have cause to shy away from pronouncements. However, with a rashness incited by gratifications in providing microbial research tools for such scientists as vitamin biochemists and photobiological physicists, we shall advance some notions. Chemists can create compounds faster than biologists can test them-unless screening procedures become more effective. Two kinds of nets are necessary in an effective screening procedure: (1) one sufficiently wide to detect all classes of cytotoxic compounds, and (2) one sufficiently fine meshed to guide the choice of clinically useful compounds within a particular class of cytotoxic agents. There is no compelling reason for the coarse and the fine-meshed nets to use the same microorganisms.

Chapter 8 Culture Media for Euglena gracilispter1

Publisher Summary This chapter reviews Euglena gracilis group II strains, which may also include var. bacillaris . All have an intense photosynthesis of the green-plant type, and in the dark, given various simple substrates, grow as colorless cells with equal or even superior vigor. They again turn green in a few hours on restoration to light. Permanently bleached strains are easily induced. This array of organisms simplifies decision as to whether a substance is localized in the chloroplast; examination of light- vs. dark-grown cultures generally settles the question. As such inquiries increasingly revolve around trace constituents and large quantities of cells are often needed, this chapter emphasizes high-yield media and how to compound media as dry mixes, which may be prepared cheaply in bulk and have a long shelf life. The use of Euglena for vitamin B 12 assay enhances the desirability of high-yield media, which permit a linear response through a wide range of vitamin B 12 concentrations along with rapid growth.

Study of the cellular action of drugs with protozoa. I. effect of 1-aminocyclopentane-1-carboxylic acid and 1-amino-3-methylcyclohexane-1-carboxylic acid on the phytoflagellate ochromonas danica

Abstract The tumor-inhibiting cyclic amino acids, 1-amino cyclo pentane-1-carboxylic acid (ACP) and 1-amino-3-methyl cyclo hexane-1-carboxylic acid (AMCH) inhibit the multiplication of Ochromonas danica . This inhibition by ACP is annulled by l -alanine and glycine in that order; inhibition by AMCH is annulled by l -leucine.