Host-dependent microbes.

Abstract

This diatribe against the injunction of Polonius to Laertes: "Neither a borrower nor a lender be" [Hamlet: Act I, scene iii], is not intended to affront the memory of an inspired author. Shakespeare is exonerated. Possibly he did not consider how little Polonius knew about differences between dependencies in men and in microbes.

Tritirachium egenum, a thiamine- and siderophore-auxotrophic fungal species isolated from a Penicillium rugulosum

“…The functional equivalence of a fungal extract, which supported the growth of mycotrophein‐deficient fungi, and an iron‐binding compound on the growth of a siderophore‐dependent bacterium, was already observed by N.E. Morrison (unpublished data, but reported by Hanks, 1966). Considering that mycotrophein is found in the mycelia as well as in the culture filtrate of many fungi, excluding the Mucorales , and because mycotrophein‐deficient fungi can grow only with fungal species that produce hydroxamate‐type siderophores, never with the Mucorales , which seem to produce none, this functional equivalence suggests that mycotrophein may be a hydroxamate‐type siderophore.…”

Comparative biology of intracellular parasitism.

“…Relatives of intracellular parasites among modern extraceilular parasites. If intracellular parasites have actually descended from extracellular oines, then extracellular relatives of present day intracellar parasites should be recognizable (164). A case can be made for Rochalimaea quintana (450), the trench fever agent, being such a relative.…”

Mycobactins: iron-chelating growth factors from mycobacteria.

“…Although M. paratuberculosis has this highly specific requirement of mycobactin for growth, Morrison has found conditions under which various strains of the organism will grow at least slowly without supplementation by mycobactin. These involve the use of unusually acid conditions, preferably around pH 5.0, and growth in a simple glucose-containing medium which has been autoclaved at pH 5.5 (34,50). The autoclave treatment produces unidentified compounds having absorption maxima at 230 and 290 nm.…”