IN an investigation of the possible effects of an electric field on growth processes in bacteria, we have discovered a new and interesting effect. In E. coli, the presence of certain group VIIIb transition metal compounds in concentrations of about 1–10 parts per million of the metal in the culture medium causes an inhibition of the cell division process. The bacteria form long filaments, up to 300 times the normal length, which implies that the growth process is not markedly affected.

Inhibition of Cell Division in Escherichia coli by Electrolysis Products from a Platinum Electrode

Treatment of staphylococcal infections with penicillin by intermittent sterilisation

Further observations on penicillin

Phages are the most abundant entity in the biosphere and outnumber bacteria by a factor of 10. Phage DNA may also constitute 20% of bacterial genomes; however, its role is ill defined. Here, we explore the impact of cryptic prophages on cell physiology by precisely deleting all nine prophage elements (166 kbp) using Escherichia coli. We find that cryptic prophages contribute significantly to resistance to sub-lethal concentrations of quinolone and β-lactam antibiotics primarily through proteins that inhibit cell division (for example, KilR of rac and DicB of Qin). Moreover, the prophages are beneficial for withstanding osmotic, oxidative and acid stresses, for increasing growth, and for influencing biofilm formation. Prophage CPS-53 proteins YfdK, YfdO and YfdS enhanced resistance to oxidative stress, prophages e14, CPS-53 and CP4-57 increased resistance to acid, and e14 and rac proteins increased early biofilm formation. Therefore, cryptic prophages provide multiple benefits to the host for surviving adverse environmental conditions.

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Cryptic prophages help bacteria cope with adverse environments

This review focuses on the era of antibiosis that led to a better understanding of bacterial morphology, in particular the cell wall component peptidoglycan. This is an effort to take readers on a tour de force from the concept of antibiosis, to the serendipity of antibiotics, evolution of beta-lactam development, and the molecular biology of antibiotic resistance. These areas of research have culminated in a deeper understanding of microbiology, particularly in the area of bacterial cell wall synthesis and recycling. In spite of this knowledge, which has enabled design of new even more effective therapeutics to combat bacterial infection and has provided new research tools, antibiotic resistance remains a worldwide health care problem.

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Beta-lactam Antibiotics: From Antibiosis to Resistance and Bacteriology

WHILE working with Chain, Florey and others on the inhibition of bacterial growth by penicillin1, I noticed that concentrations of less than full inhibiting power caused a change in the appearance of the growth of Cl welchii in fluid media The normal uniform turbidity was replaced by a flocculent growth with a heavy deposit Microscopical examination showed an extreme elongation of the majority of the cells, which took the form of unsegmented filaments ten or more times longer than the average normal cell

A. D. Gardner

Papers

Morphological Effects of Penicillin on Bacteria