The Ethics of Medical Practitioner Migration From Low-Resourced Countries to the Developed World: A Call for Action by Health Systems and Individual Doctors

Medical migration appears to be an increasing global phenomenon, with complex contributing factors. Although it is acknowledged that such movements are inevitable, given the current globalized economy, the movement of health professionals from their country of training raises questions about equity of access and quality of care. Concerns arise if migration occurs from low- and middle-income countries (LMICs) to high-income countries (HICs). The actions of HICs receiving medical practitioners from LMICs are examined through the global justice theories of John Rawls and Immanuel Kant. These theories were initially proposed by Pogge (1988) and Tan (1997) and, in this work, are extended to the issue of medical migration. Global justice theories propose that instead of looking at health needs and workforce issues within their national boundaries, HICs should be guided by principles of justice relevant to the needs of health systems on a global scale. Issues of individual justice are also considered within the framework of rights and social responsibilities of individual medical practitioners. Local and international policy changes are suggested based on both global justice theories and the ideals of individual justice.     

Evaluation of a FRET-Peptide Substrate to Predict Virulence in Pseudomonas aeruginosa

Pseudomonas aeruginosa produces a number of proteases that are associated with virulence and disease progression. A substrate able to detect P. aeruginosa-specific proteolytic activity could help to rapidly alert clinicians to the virulence potential of individual P. aeruginosa strains. For this purpose we designed a set of P. aeruginosa-specific fluorogenic substrates, comprising fluorescence resonance energy transfer (FRET)-labeled peptides, and evaluated their applicability to P. aeruginosa virulence in a range of clinical isolates. A FRET-peptide comprising three glycines (3xGly) was found to be specific for the detection of P. aeruginosa proteases. Further screening of 97 P. aeruginosa clinical isolates showed a wide variation in 3xGly cleavage activity. The absence of 3xGly degradation by a lasI knock out strain indicated that 3xGly cleavage by P. aeruginosa could be quorum sensing (QS)-related, a hypothesis strengthened by the observation of a strong correlation between 3xGly cleavage, LasA staphylolytic activity and pyocyanin production. Additionally, isolates able to cleave 3xGly were more susceptible to the QS inhibiting antibiotic azithromycin (AZM). In conclusion, we designed and evaluated a 3xGly substrate possibly useful as a simple tool to predict virulence and AZM susceptibility.     

Army ant males lose seasonality at a site on the equator

Army ants are keystone predators in the tropics and subtropics. During reproduction, males fly between colonies to mate with unmated, wingless queens. The males of most species are attracted to lights, and thus their presence and the timing of reproduction can be monitored using light traps. Previous studies examined the seasonality of army ant male reproduction and its relationship to climate factors at individual sites, but less is known about variation among sites. We examined army ant male flight seasonality at three sites: (1) La Selva Biological Station in Costa Rica, a site with weak temperature seasonality and moderate rainfall and day length seasonality, (2) Yasuní National Park, Ecuador, a site with no temperature or day length seasonality and very weak rainfall seasonality, and (3) the state of Paraná in southern Brazil, a site with very strong temperature, rainfall, and day length seasonality. Army ants showed strong seasonality at the La Selva and Paraná sites, and very weak to no seasonality at the Yasuní site. At La Selva and Paraná, flight times varied among species, but were very predictable from year to year, which suggests day length or temperature as predictable cues rather than rainfall. Lack of seasonal cues near the equator may be a challenge for army ant species that need to synchronize colony reproduction, and thus may have conservation implications for minimum population sizes needed to ensure stable populations.     

Selection of Arabidopsis cDNAs that partially correct phenotypes of Escherichia coli DNA-damage-sensitive mutants and analysis of two plant cDNAs that appear to express UV-specific dark repari activities

To resist terrestrial UV radiation, plants employ DNA-damage-repair/toleration (DRT) activities, as well as shielding mechanisms. Little is known about the structure and regulation of plant DRT genes. We isolated DRT cDNAs from Arabidopsis thaliana, by selecting for complementation of Escherichia coli mutants lacking all bacterial defenses against UV-light damage to DNA. These mutants are phenotypically deficient in recombinational and mutagenic toleration (RecA^–), excision repair (Uvr^–) and photoreactivation toreactivation (Phr^–). Among 840 survivors of heavily UV-irradiated (10^–7 survival) mutants harboring plasmids derived from an Arabidopsis cDNA library in the vector YES, we identified four unique plant cDNAs, designated DRT100, DRT101, DRT102, and DRT103. Drt101 and Drt102 activity were specific for UV-light damage, and complemented both UvrB^– and UvrC^– phenotypes in the dark. Apparent Uvr^– correction efficiencies were 1 to 40% for Drt101, and 0.2 to 15% for Drt102, depending on the UV fluence. Drt101 and Drt102 showed no extensive amino-acid homology with any known DNA-repair proteins. Drt100 appeared to correct RecA^–, rather than Uvr^–, phenotypes. Although the light dependence of Drt103 activity was consistent with its identification as a photoreactivating enzyme, its predicted amino-acid sequence did not resemble known photolyase sequences. The N-terminal coding sequence of Drt101 suggests that it is targeted to chloroplasts, as reported for Drt100. These cDNAs afforded only modest increases in survival during the original selection procedure. The fact that they were readily isolated nevertheless suggests that selections may be made powerful enough to overcome barriers to expression and function in bacteria, at least for cDNAs of reasonable abundance.