SummaryThe intestinal commensal bacterium, Enterococcus faecalis, is unusual among prokaryotic organisms in its ability to produce substantial extracellular superoxide. Transposon mutagenesis, allelic replacement, and electron spin resonance (ESR)-spin trapping showed that superoxide production and generation of derivative hydroxyl radical were dependent on membrane-associated demethylmenaquinone. Extracellular superoxide was generated through univalent reduction of oxygen by reduced demethylmenaquinone. Moreover, extracellular superoxide production was inhibited by exogenous haematin, an essential cofactor for cytochrome bd, and by fumarate, a substrate for fumarate reductase. As integral membrane quinol oxidases, cytochrome bd and fumarate reductase redox cycle demethylmenaquinone, and are necessary for aerobic and anaerobic respiration respectively. A rat model of intestinal colonization demonstrated that conditions exist in the mammalian intestinal tract that permit a mode of respiration for E. faecalis that results in the formation of hydroxyl radical. These results identify and characterize the mechanism by which E. faecalis generates extracellular free radicals.

We sought to determine whether Tourette syndrome (TS) was related to attentional disturbance independent of Attention Deficit Hyperactivity disorder (ADHD) and obsessive-compulsive symptoms (OCS), two comorbid conditions associated with attentional problems in other populations. Participants were 74 children [21 with uncomplicated TS (TS-Only), 14 with TS and ADHD (TS-ADHD), 21 with ADHD, and 18 controls]. Impaired sustained attention and impulsivity on a Continuous Performance Task were uncommon in the TS-Only group, but common in TS-ADHD and ADHD. The TS-ADHD group was less impulsive than the ADHD group, but had a higher rate of whole-body tics than the TS-Only group, raising questions about the diagnosis of ADHD in TS. OCS was not an independent risk factor for attention problems. However, the association of tic severity and impulsivity was consistent with the theory that TS involves dysfunction in cortical-subcortical circuits mediating behavioral inhibition.

A previously healthy captive female bottlenosed dolphin (Tursiops truncatus) died suddenly. At necropsy, Clostridium perfringens was isolated from dorsal muscle, blood, left heart ventricle, thoracic fluid, and abdominal fluid. An identical strain was recovered from pool water. A male dolphin in the same pool had inflicted several "rake" marks on the dorsal surface of the female. Water-borne bacteria probably entered these lesions which served as the focus for anaerobe penetration and spread.

For proper husbandry, it is important to sample the environment from which marine mammals for captivity are taken and to monitor the animals frequently over an extended period. Samples for microbiological analysis were collected from 20 beluga whales during capture in the Churchill River. Seven animals were retained in three U.S. aquaria with anal and blowhole cultures taken over a 945-d period. Bacteria isolated from whales at capture included many soil and water forms found also in environmental samples. Pasteurella multocida was isolated from three whales at capture and infrequently several times in captivity from two of these which were studied the most intensively. From this latter group maintained at Mystic (CT) Marinelife Aquarium, the most frequently recovered bacteria from both animals were members of the Achromobacter-Acinetobacter-Alcaligenes-CDC IV E-Moraxella-Pasteurella-Pseudomonas group, Escherichia coli, Pseudomonas putrefaciens, Staphylococcus epidermidis, Streptococcus faecalis, and Vibrio fluvialis. Only one of these whales yielded cultures of Klebsiella pneumoniae, Plesiomonas shigelloides, and coagulase positive Staphylococcus aureus. Species of Acinetobacter, Aeromonas, Pseudomonas, and Vibrio were most common in whales maintained at the other aquaria although, as noted for animals at Mystic, several species were isolated from some samples and were absent in others.

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