Journal of Eukaryotic MicrobiologyVolume 64, Issue 4 p. 558-559 In Memoriam In Memoriam: Michael Levandowsky (1935–2016) Cyrus J. Bacchi, Cyrus J. Bacchi Haskins Laboratories, Pace University, New York, 10038 New YorkSearch for more papers by this authorThomas Gorrell, Thomas Gorrell Haskins Laboratories, Pace University, New York, 10038 New York School of Visual Arts, New York, 10010 New YorkSearch for more papers by this authorGeorge McManus, George McManus Marine Sciences, University of Connecticut, Groton, 06340 ConnecticutSearch for more papers by this authorNigel Yarlett, Corresponding Author Nigel Yarlett nyarlett@pace.edu orcid.org/0000-0002-7493-4346 Haskins Laboratories, Pace University, New York, 10038 New York Department of Chemistry and Physical Sciences, Pace University, New York, 10038 New York Correspondence N. Yarlett, Haskins Laboratories, Pace University, New York, NY 10038, USA Telephone number: +1 212 346-1853; FAX number: +1 212 346-1586; e-mail: nyarlett@pace.eduSearch for more papers by this author Cyrus J. Bacchi, Cyrus J. Bacchi Haskins Laboratories, Pace University, New York, 10038 New YorkSearch for more papers by this authorThomas Gorrell, Thomas Gorrell Haskins Laboratories, Pace University, New York, 10038 New York School of Visual Arts, New York, 10010 New YorkSearch for more papers by this authorGeorge McManus, George McManus Marine Sciences, University of Connecticut, Groton, 06340 ConnecticutSearch for more papers by this authorNigel Yarlett, Corresponding Author Nigel Yarlett nyarlett@pace.edu orcid.org/0000-0002-7493-4346 Haskins Laboratories, Pace University, New York, 10038 New York Department of Chemistry and Physical Sciences, Pace University, New York, 10038 New York Correspondence N. Yarlett, Haskins Laboratories, Pace University, New York, NY 10038, USA Telephone number: +1 212 346-1853; FAX number: +1 212 346-1586; e-mail: nyarlett@pace.eduSearch for more papers by this author First published: 11 May 2017 https://doi.org/10.1111/jeu.12416Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume64, Issue4July/August 2017Pages 558-559 RelatedInformation

There are currently no laboratory or clinical guidelines for the identification and treatment of disease caused by metronidazole-resistant strains of Trichomonas vaginalis. Fifty-three isolates of T. vaginalis from cases of refractory vaginitis in the United States (26 states) and Canada were tested for aerobic and anaerobic metronidazole susceptibility, and after various dosages of metronidazole, the therapeutic outcomes were evaluated for 31 of these cases. The mean aerobic metronidazole susceptibility of these isolates was 195.5 micrograms/ml (range, 12.5-greater than 1,000), which was about eightfold higher than that seen in isolates that were not resistant to metronidazole. The mean anaerobic susceptibility was 5 micrograms/ml (range, 1.6-25), which was about threefold higher than that of isolates from nonresistant strains. The average aerobic-to-anaerobic ratio of metronidazole susceptibility in the highly resistant isolates was more than 3.5-fold greater than that seen in the nonresistant isolates. White women accounted for 88% of the resistant infections. Of 31 cases that were re-treated and monitored, the highest average dose that failed to achieve a cure was 2.1 g of metronidazole/day given over an eight-day period; 27 (87%) of 31 cases were ultimately cured with an average dosage of 2.6 g of metronidazole/day given over a mean period of nine days. Resistance to treatment with metronidazole varied from mild to severe, and the resistance was occasionally more severe than the susceptibility values indicate.

We have studied the spontaneous killing of B5(59) melanoma cells by Bacillus Calmette-Guérin (BCG)-elicited macrophages under strictly anaerobic conditions to investigate the role of oxygen in macrophage-mediated cytotoxicity. The number of melanoma cells capable of forming colonies after aerobic or anaerobic incubation with BCG-macrophages was used as the index of cytotoxicity. The BCG-macrophages killed melanoma cells regardless of the amount of oxygen present. The killing observed was proportional to the ratio of effector cells added; a ratio of 25:1 effector to target cells was required to achieve nearly 90% cytotoxicity both aerobically and anaerobically. This cytotoxicity was not dependent on a diffusible macrophage product nor on alteration of the medium by macrophages, since tumor cells incubated in the same culture medium, but not in contact with a mixed population of tumor cells and macrophages, were not killed. These results also indicated that macrophage-mediated cytotoxicity was dependent on macrophage-tumor cell contact. The mechanism responsible for the oxygen-independent cytotoxicity is unknown at present.

A ferredoxin was purified from the anaerobic protozoon Trichomonas vaginalis. The protein had a molecular weight of 12,000 as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, gel filtration and amino acid analysis. The protein contained seven 1/2-cystine (cystine plus cysteine) residues and one tyrosine, and lacked tryptophan. Chemical analysis and spectral properties of the ferredoxin indicated the presence of a [2Fe-2S] cluster. The complex optical spectrum of the native ferredoxin had peaks at 310 and 450 nm and shoulders near 415 and 550 nm. The molar absorbance of the protein at 450 nm was 8,000m −1 × cm−1. The EPR spectrum of reduced ferredoxin had two features at g values of 2.02 and 1.94 and revealed axial symmetry. Results of subcellular fractionation studies indicated the ferredoxin to be a major iron-sulfur protein of the cells and to be located in the hydrogenosome. The ability of the ferredoxin to function as an electron carrier was demonstrated by its reduction by pyruvate: ferredoxin oxidoreductase and hydrogenase as detected by EPR spectroscopy and by its stimulation of metronidazole reduction by these enzymes. These observations implicate ferredoxin as an important electron transport component in hydrogenosomes of T. vaginalis.