What Is Unfair about Unequal Brute Luck? An Intergenerational Puzzle.

According to Luck egalitarians, fairness requires us to bring it about that nobody is worse off than others where this results from brute bad luck, but not where they choose or deserve to be so. In this paper, I consider one type of brute bad luck that appears paradigmatic of what a Luck Egalitarian ought to be most concerned about, namely that suffered by people who are born to badly off parents and are less well off as a result. However, when we consider what is supposedly unfair about this kind of unequal brute luck, luck egalitarians face a dilemma. According to the standard account of luck egalitarianism, differential brute luck is unfair because of its effects on the distribution of goods. Yet, where some parents are worse off because they have chosen to be imprudent, it may be impossible to neutralize these effects without creating a distribution that seems at least as unfair. This, I argue, is problematic for luck egalitarianism. I, therefore, explore two alternative views that can avoid this problem. On the first of these, proposed by Shlomi Segall, the distributional effects of unequal brute luck are unfair only when they make a situation more unequal, but not when they make it more equal. On the second, it is the unequal brute luck itself, rather than its distributional effects, that is unfair. I conclude with some considerations in favour of this second view, while accepting that both are valid responses to the problem I describe.

Inhibition of the cytochrome bd-terminated NADH oxidase system in Escherichia coli K-12 by divalent metal cations.

Co(II), Zn(II) and Cd(II) ions inhibited NADH oxidase activity in membranes prepared from two cytochrome bo'-deficient mutants of Escherichia coli K-12 with the following order of potency: Zn(II) > Cd(II) >> Co(II). The degree of inhibition exhibited by these metal ions was not diminished in membranes which contained elevated levels of the cytochrome bd complex, suggesting that the most sensitive site precedes this complex in the aerobic respiratory chain. For each of the metal ions studied, inhibition was determined to be of the non-competitive type. Based upon the efficacy with which EDTA alleviated inhibition, Co(II), Zn(II) and Cd(II) ions are proposed to inhibit NADH oxidase activity by binding to at least two sites in the respiratory chain with significantly different affinities.

Metal ion-catalysed hydrolysis of ampicillin in microbiological growth media.

Anodic stripping voltammetry of bacterial growth medium containing copper(II) and ampicillin shows that Cu(II) is complexed by the antibiotic and that this complex decomposes to give Cu(II) complexes with ligands derived from ampicillin. At pH 7, substantial decomposition of ampicillin occurs over a few minutes, and even the very low levels of Cu(II) in Chelex-extracted medium are able effectively to catalyse the decomposition. The significance of this observation was shown during the screening of an Escherichia coli cosmid library for clones exhibiting increased resistance to Zn(II), Co(II) or Cd(II); the unexpected growth of the ampicillin-sensitive host E. coli strain on Luria-Bertani plates containing ampicillin and any of these metals was attributed to metal ion-catalysed decomposition of ampicillin. The instability of ampicillin (and other beta-lactam antibiotics) to metal ion-catalysed hydrolysis means that great care must be taken to ensure that such reactions do not occur in growth media. Furthermore, it is clear that double selection for resistance to ampicillin and metals such as Cu(II), Zn(II), Co(II) and Cd(II) is impossible.

Evidence for the transport of zinc(II) ions via the pit inorganic phosphate transport system in Escherichia coli.

A locus involved in zinc(II) uptake in Escherichia coli K-12 was identified through the generation of a zinc(II)-resistant mutant by transposon (Tn10dCam) mutagenesis. The mutation was located within the pitA gene, which encodes the low-affinity inorganic phosphate transport system (Pit). The pitA mutant accumulated reduced amounts of zinc(II) when exposed to 0.5-2.0 mM ZnSO(4) during growth in Luria-Bertani medium.

Zinc(II) tolerance in Escherichia coli K-12: evidence that the zntA gene (o732) encodes a cation transport ATPase.

A transposon (Tn 10dCam) insertion mutant of Escherichia coli K-12 was isolated that exhibited hypersensitivity to zinc(II) and cadmium(II) and, to a lesser extent, cobalt(II) and nickel (II). The mutated gene, located between 75.5 and 76.2 min on the chromosome, is named zntA (for Zn(II) transport or tolerance). The metal-sensitive phenotype was complemented by a genomic DNA clone mapping at 3677.90-3684.60 kb on the physical map. Insertion of a kanamycin resistance (KnR) cassette at a SalI site in a subcloned fragment generated a plasmid that partially complemented the zinc(II)-sensitive phenotype. DNA sequence analysis revealed that the KnR cassette was located within the putative promoter region of an ORF (o732 or yhhO) predicted to encode a protein of 732 amino acids, similar to cation transport P-type ATPases in the Cpx-type family. Inverse PCR and sequence analysis revealed that the Tn 10dCam element was located within o732 in the genome of the zinc(II)-sensitive mutant. The zntA mutant had elevated amounts of intracellular and cell surface-bound Zn(II), consistent with the view that zntA+ encodes a zinc(II) efflux protein. Exposure of the zntA mutant to cobalt(II) and cadmium(II) also resulted in elevated levels of intracellular and cell surface-bound metal ions.

The diversity of gas vesicle genes in Planktothrix rubescens from Lake Zürich.

Part of the gas vesicle gene cluster was amplified by PCR from three strains of Planktothrix rubescens isolated from Lake Zürich, Switzerland. Each contains multiple alternating copies of gvpA and gvpC. All of the gvpA sequences in the different strains are identical. There are two types of gvpC: gvpC20, of length 516 bp, encodes a 20 kDa protein of 172 amino acid residues (whose N-terminal amino acid sequence is homologous with the sequence of GvpC in Planktothrix [Oscillatoria] agardhii); gvpC16, of length 417 bp, encodes a 16 kDa protein of 139 amino acid residues that differs in lacking an internal 33-residue section. An untranslated 72 bp fragment from the 3' end of gvpC, designated omegaC, is also present in some strains. The two types of gvpC and presence of omegaC could be distinguished by the different lengths of PCR amplification products obtained using pairs of oligonucleotide primers homologous to internal sequences in gvpC and gvpA. Three genotype classes were found: GV1, containing only gvpC20; GV2, containing gvpC20 and omegaC; and GV3, containing gvpC16, gvpC20 and omegaC. Subclasses of GV2 and GV3 contained either one or two copies of omegaC. The accompanying paper by D. I. Bright & A. E. Walsby (Microbiology 145, 2769-2775) shows that strains of the GV3 genotype produce gas vesicles with a higher critical pressure than those of GV1 and GV2. A PCR survey of 185 clonal cultures of P. rubescens isolated from Lake Zürich revealed that 3 isolates were of genotype GV1, 73 were of GV2 and 109 were of GV3. The PCR technique was used to distinguish the gas vesicle genotype, and thence the associated critical-pressure phenotype, of single filaments selected from lakewater samples. Sequence analysis of the 16S rDNA and of regions within the operons encoding phycoerythrin, phycocyanin and Rubisco confirmed that these strains of Planktothrix form a tight phylogenetic group.

Expression of lux genes in a clinical isolate of Streptococcus pneumoniae: using bioluminescence to monitor gemifloxacin activity.

A clinical isolate of Streptococcus pneumoniae was transformed with a plasmid containing the lux operon of Photorhabdus luminescens that had been modified to function in gram-positive bacteria. Cells containing this plasmid produced light stably and constitutively, without compromising the growth rate. Light output was correlated with measurements of optical density and viable counts during exponential growth and provided a sensitive, real-time measure of the pharmacodynamics of the fluoroquinolone gemifloxacin.

Gas vesicle genes in Planktothrix spp. from Nordic lakes: strains with weak gas vesicles possess a longer variant of gvpC.

In cyanobacteria of the genus Planktothrix:, there are three length variants of gvpC, the gene that encodes the outer protein of the gas vesicle. Sequence analyses indicated that the three allelic variants of gvpC differ principally in the presence or absence of a 99 nt and a 213 nt section. Strains with the new variant, gvpC(28), which encodes a 28 kDa form of GvpC, produce gas vesicles that collapse at the relatively low critical pressure (p(c)) of 0.61-0.75 MPa. The authors have identified 12 classes of gvp genotypes that differ in the number and arrangement of alternating gvpA-gvpC genes and in the presence of OmegaC, a fragment of gvpC. The gvpC(28) gene was found to be the most common variant of gvpC amongst 71 strains of Planktothrix: isolated from Nordic lakes: 34 strains contained only gvpC(28); 22 strains, which possessed only the shorter gvpC(20) gene, produced gas vesicles with a higher p(c) of 0.76-0.91 MPa; and 15 strains, which possessed both gvpC(20) and gvpC(28), also produced the stronger gas vesicles. Genotypes with only the gvpC(28) genes were more common amongst green Planktothrix: strains (33 out of 38) than red strains (one out of 33). It is suggested that there is competition between the strains producing the two types of gas vesicles, with the stronger forms favoured in lakes deeper than 60 m, in which the combination of cell turgor pressure and hydrostatic pressure can collapse the weaker gas vesicles. The fact that none of the Nordic lakes are deeper than 67 m would explain the absence of the gvpC(16)-containing strains that produce even narrower gas vesicles of p(c) 1.0-1.2 MPa, which are common in the much deeper Lake Zürich.

Arthroscopic synovectomy of the metacarpophalangeal joint in refractory rheumatoid arthritis: a technique.

Arthroscopic synovectomy was performed on 29 metacarpophalangeal joints belonging to 21 patients with refractory rheumatoid arthritis. This article describes the method of anesthesia, landmarks, and operative technique. Short-term (12-month) results and patient satisfaction have been excellent. No complications were noted. We conclude that arthroscopic synovectomy of the metacarpophalangeal joints in patients with refractory rheumatoid arthritis can be performed safely and effectively. Possibilities for improvement of the technique as well as possible uses of the technique in research are discussed.

Genetic diversity within populations of cyanobacteria assessed by analysis of single filaments.

We have developed a technique for determining the genetic structure of populations of filamentous cyanobacteria. The sequence diversity at specific gene loci is first characterised in a range of clonal cultures; subsequent analysis involves individual trichomes collected directly from natural populations. This technique has been used to examine the population genetic structure of Nodularia in the Baltic Sea and Planktothrix in Lake Zürich. For Nodularia, studies utilising four polymorphic loci reveal that even though there is a degree of linkage disequilibrium, horizontal transfer of genetic information has been sufficient to generate many of the possible allelic combinations. Analyses reveal both spatial and temporal variation in population genetic structure. Other studies of both Nodularia and Planktothrir have shown a correlation between particular alleles at the gvpC locus and the critical pressure of the gas vesicles that accumulate within the cell. We are now investigating how the natural selection of different gas vesicle phenotypes, imposed by changes in the depth of the upper mixed layer of the water column, affects the relative success of individual cyanobacteria possessing different gvpC alleles.