Microbial adaptations to the psychrosphere/piezosphere.

Low temperature and high pressure deep-sea environments occupy the largest fraction of the biosphere. Nevertheless, the molecular adaptations that enable life to exist under these conditions remain poorly understood. This article will provide an overview of the current picture on high pressure adaptation in cold oceanic environments, with an emphasis on genetic experiments performed on Photobacterium profundum. Thus far genes which have been found or implicated as important for pressure-sensing or pressure-adaptation include genes required for fatty acid unsaturation, the membrane protein genes toxR and rseC and the DNA recombination gene recD. Many deep-sea bacteria possess genes for the production of omega-3 polyunsaturated fatty acids. These could be of biotechnological significance since these fatty acids reduce the risk of cardiovascular disease and certain cancers and are useful as dietary supplements.

Stress response of Escherichia coli to elevated hydrostatic pressure.

The response of exponentially growing cultures of Escherichia coli to abrupt shifts in hydrostatic pressure was studied. A pressure upshift to 546 atm (55,304 kPa) of hydrostatic pressure profoundly perturbed cell division, nucleoid structure, and the total rate of protein synthesis. The number of polypeptides synthesized at increased pressure was greatly reduced, and many proteins exhibited elevated rates of synthesis relative to total protein synthesis. We designated the latter proteins pressure-induced proteins (PIPs). The PIP response was transient, with the largest induction occurring approximately 60 to 90 min postshift. Fifty-five PIPs were identified. Many of these proteins are also induced by heat shock or cold shock. The PIP demonstrating the greatest pressure induction was a basic protein of 15.6 kDa. High pressure inhibits growth but does not inhibit the synthesis of stringently controlled proteins. Cold shock is the only additional signal which has been found to elicit this type of response. These data indicate that elevated pressure induces a unique stress response in E. coli, the further characterization of which could be useful in delineating its inhibitory nature.

Arthroscopic management of osteochondritis dissecans of the first metatarsal head.

Osteochondritis dissecans of the first metatarsal head can be painfully disabling in the adolescent. It may be the forerunner of adolescent and adult hallux rigidus. Arthroscopic surgical treatment of this osteochondritis dissecans lesion is technically feasible. The case reported here suggests that arthroscopic treatment, at an early stage, can render a patient symptom-free and allow a return to full activity.

Arthroscopic assisted internal fixation of certain fractures about the knee.

A technique is presented by which single-fragment, major intra-articular fractures about the knee can be reduced anatomically under arthroscopic control and internally fixed with percutaneously placed cancellous screws. A displaced intra-articular fracture of the femoral condyle and a tibial plateau fracture were treated utilizing this technique. Both patients obtained excellent results with rapid return of function of the injured limb.

Identification of Escherichia coli region III flagellar gene products and description of two new flagellar genes.

Region III flagellar genes in Escherichia coli are involved with the assembly and rotation of the flagella, as well as taxis. We subcloned the flaB operon from a lambda fla transducing phage onto plasmid pMK2004. Two additional genes were found at the flaB locus, and we subdivided the flaB gene into flaB1, flaBII, and flaBIII. The cheY suppressor mutations which have previously been mapped to flaB were further localized to flaB11 (Parkinson et al., J. Bacteriol. 155:265-274, 1983). Until now, gene product identification has not been possible for these genes because of their low levels of gene expression. Overexpression of the flagellar genes was accomplished by placing the flaB operon under the control of the lacUV5 or tac promoters. Plasmid-encoded proteins were examined in a minicell expression system. By correlating various deletions and insertions in the flaB operon with the ability to complement specific flagellar mutants and code for polypeptides, we made the following gene product assignments: flaB 1, 60 kilodaltons; flaB 11, 38 kilodaltons; flaB111, 28 kilodaltons; flaC, 56 kilodaltons; fla0, 16 kilodaltons; and flaE, 54 kilodaltons.

Pasteurella multocida infection in the hand.

We have discussed 13 patients with Pasteurella multocida infection of the hand, six of whom developed chronic hand impairment as a result of the infection. It is thus apparent that chronic morbidity following Pasteurella infection of the hand is nearly 50 percent. Despite a fairly wide antibiotic susceptibility pattern of this organism, the infection may have long-term consequences such as osteomyelitis, or small joint stiffness due to paraarticular infection. We wish to emphasize the rapid evolution of the clinical picture following inoculation and the need for vigorous antibiotic therapy supplemented by rest, elevation immobilization, and occasional surgical decompression or drainage. At this time, the preferred antibiotic for initial care would appear to be on of the cephalosporins changed to penicillin for the culture-proven infection.