John D. Bu'Lock

Extremely Thermophilic Acidophilic Bacteria Convergent with Sulfolobus Acidocaldarius

A series of extremely thermophilic acidophilic bacteria has been characterized as closely resembling the species Sulfolobus acidocaldarius except for a totally different guanosine-cytosine content in the DNA; some conceptual consequences of this situation are discussed. Both organisms also share special features, including a very characteristic type of ether lipid, with other extreme acidophilic thermophiles.

Intermediary metabolism and antibiotic synthesis.

Publisher Summary This chapter discusses intermediary metabolism and antibiotic synthesis. As the clinical utility of penicillin has been established, the study of antibiotics has tended to dominate the approach to certain aspects of microbiology. Not only has the “screening” process involved superficial examinations of an enormous range of microorganisms, but, more fundamentally, great efforts have been made toward understanding the mode of action of antibiotic substances and toward the improvement and control of industrial fermentations. It is important to admit that the distinction between antibiotically active and inactive metabolites is an artifact of humanly contrived situations, and has less significance to the producing organism. Given the generally acceptable view that there are basic patterns of general metabolism, on which the variety of organic systems imposes relatively minor modifications, one can define secondary metabolites as having, by contrast, a restricted distribution (which is almost species specific) and no obvious function in general metabolism.

Effects of temperature on ether lipid composition of Caldariella acidophila

The composition of the ether lipids of a strain of Caldariella acidophila, with respect to the different numbers of cyclizations of the biphytanyl components, is shown to differ between the various complex lipid classes, but the degree of cyclization increases systematically with the growth temperature in the range 75–89°. The problem of distinguishing adaptive from phyletic features in archaebacterial lipids is considered.

Chemical structure of the ether lipids of thermophilic acidophilic bacteria of the Caldariella group

Abstract The lipids of the Caldariella group of extremely thermophilic acidophilic bacteria are based on a 72-membered macrocyclic tetraether made up from two C40 diol units and either two glycerol units or one glycerol and one nonitol. The C40 components have the 16,16′-biphytanyl skeleton and the detailed structure of three of them is established.

Complex lipids of Caldariella acidophila, a thermoacidophile archaebacterium

Abstract Isoprenoid ether lipids are common to the ‘urkingdom’ archaebacteria, within which members of the Caldariella group of extreme thermoacidophiles and some methanogenic species have lipids based on macrocyclic tetraethers containing two 16,16′-biphytanyl chains. As a step towards closer classification, the complex lipids of Caldariella acidophila have been more fully characterized.

Structural regularities in tetraether lipids of Caldariella and their biosynthetic and phyletic implications

Abstract Individual di(biphytanyl) diglycerol tetraether lipids from thermoacidophile archaebacteria of the Caldariella series, with differently cyclized biphytanyl components, are separated and shown to have structures 8–12 , with the glycerol and biphytanyl components demonstrably both antiparallel and with partial assignments of stereochemistry. Tetraethers with alternative arrangements of the components are absent. The structures allow previous observations on these and related lipids to be rationalized both biosynthetically and phyletically.

The Apocarotenoid System of Sex Hormones and Prohormones in Mucorales

Abstract The sexual process in Mucoraceous fungi is mediated by a system of C 18 apocarotenoid substances. Of these, the prohormones are mating-type-specific products from a branching pathway of metabolism, and each type can be converted into the trisporic acid hormones only by the mating-type in which it is not formed. The trisporic acids are the actual effectors of sexual differentiation and they also depress the production of the prohormones from which they arise. The presence or absence of particular reaction steps in each mating-type is shown to be consistent with this picture, and the structural evidence for the individual prohormones is presented. It is shown that the trisporic acids exert their effects by way of transcriptional regulation of new RNA synthesis, and that their action is at least partly mediated by adenosine cyclic monophosphate.

The caldariella group of extreme thermoacidophile bacteria: Direct comparison of lipids in Sulfolobus, Thermoplasma, and the MT strains

Abstract It is shown that the lipids from 5 extreme thermoacidophile bacteria of the Caldariella group—2 isolates of Sulfolobus acidocaldarius, one of Thermoplasma acidophila, and 2 of the MT series—are all based on the same type of cyclic diether combining glycerol and one of a series of very unusual C40 isoprenoid diols. The relative proportions of the different C40 components in each isolate have been determined.

A study of continuous ethanol production using a highly flocculent yeast in the gas lift tower fermenter

Abstract A highly flocculent strain of the yeast Saccharomyces uvarum was used to convert glucose to ethanol and CO 2 continuously at a temperature of 33 °C and a pH of 4.5. The yeast was grown in a single-stage gas lift tower fermenter, the design of which allowed the reactor to run anaerobically for long periods with a biomass holdup exceeding 100 g l −1 (dry weight) and permitted virtually 100% cell retention at hydraulic dilution rates greater than 2.5 h −1 . Unstructured parabolic and linear equations were proposed to describe the variation in yeast growth and ethanol production with ethanol concentration. In combination with the fermenter model, these equations enabled prediction of all steady state parameters for ethanol concentrations of 0 – 73 g l −1 . Such parameters were in close agreement with the experimental data obtained. Yeast growth could not be correlated with ethanol production in the traditional manner, although non-competitive ethanol inhibition was observed and the dependence of product formation on glucose concentration was in agreement with Michaeli—Menten kinetics. Evaporative ethanol losses were accurately calculated to be less than 0.6% of the total ethanol produced and were therefore neglected. The maximum theoretical ethanol concentration and productivity attainable were 75 g l −1 and 50 g l −1 h −1 respectively with a mean ethanol yield on glucose of 83% of the theoretical value.

Cyclohexane fatty acids from a thermophilic bacterium

In the saponifiable lipids of Bacillus acidocaldarius the principal components are 11-cyclohexylundecanoic and 13-cyclohexyltridecanoic acids.