Engineered nickel bioaccumulation in Escherichia coli by NikABCDE transporter and metallothionein overexpression

Mine wastewater often contains dissolved metals at concentrations too low to be economically extracted by existing technologies, yet too high for environmental discharge. The most common treatment is chemical precipitation of the dissolved metals using limestone and subsequent disposal of the sludge in tailing impoundments. While it is a cost-effective solution to meet regulatory standards, it represents a lost opportunity. In this study, we engineered Escherichia coli to overexpress its native NikABCDE transporter and a heterologous metallothionein to capture nickel at concentrations in local effluent streams. We found the engineered strain had a 7-fold improvement in the bioaccumulation performance for nickel compared to controls, but also observed a drastic decrease in cell viability due to metabolic burden or inducer (IPTG) toxicity. Growth kinetic analysis revealed the IPTG concentrations used based on past studies lead to growth inhibition, thus delineating future avenues for optimization of the engineered strain and its growth conditions to perform in more complex environments.     

Léon Athanase Gosselin (1815–1887) et ses recherches sur les maladies du testicule

Leon Athanase Gosselin was one of the greatest French surgeons of the 19th century. He successfully directed many university surgical departments and excelled in orthopaedics, anatomy, physiology and urology. Thanks to his advanced research into testicular, scrotal and spermatic cord diseases and their effects on fertilisation and virility, Gosselin is rightly considered to have been a great andrologist before this branch of medical science had been recognised.     

Insight into the protein and solvent contributions to the reduction potentials of [4Fe–4S]2+/+ clusters: crystal structures of the Allochromatium vinosum ferredoxin variants C57A and V13G and the homologous Escherichia coli ferredoxin

The crystal structures of the C57A and V13G molecular variants of Allochromatium vinosum 2[4Fe–4S] ferredoxin (AlvinFd) and that of the homologous ferredoxin from Escherichia coli (EcFd) have been determined at 1.05-, 1.48-, and 1.65-Å resolution, respectively. The present structures combined with cyclic voltammetry studies establish clear effects of the degree of exposure of the cluster with the lowest reduction potential (cluster I) towards less negative reduction potentials (E°). This is better illustrated by V13G AlvinFd (high exposure, E° = ?594 mV) and EcFd (low exposure, E° = ?675 mV). In C57A AlvinFd, the movement of the protein backbone, as a result of replacing the noncoordinating Cys57 by Ala, leads to a +50-mV upshift of the potential of the nearby cluster I, by removal of polar interactions involving the thiolate group and adjustment of the hydrogen-bond network involving the cluster atoms. In addition, the present structures and other previously reported accurate structures of this family of ferredoxins indicate that polar interactions of side chains and water molecules with cluster II sulfur atoms, which are absent in the environment of cluster I, are correlated to the approximately 180–250 mV difference between the reduction potentials of clusters I and II. These findings provide insight into the significant effects of subtle structural differences of the protein and solvent environment around the clusters of [4Fe–4S] ferredoxins on their electrochemical properties.     

Le grand vénéréologue Philippe Ricord (1800–1889) et la distinction définitive entre la gonococcie et la syphilis

Philippe Ricord, a famous French venereologist, was the first to distinguish between syphilis and gonorrhoea and founded the famous French school of venereology.     

Le “Rob de Laffecteur”: un célèbre remède antisyphilitique aux temps des charlatans

The history of “Rob de Laffecteur”, a very popular remedy for a long time due to the confused theories concerning syphilis, reflects the backward thinking in the field of venereology, even up until the second half of in the 19th century, as, in 1858, twenty years after the discoveries by Philippe Ricord, some venereologists still believed in the gonorrhoea and syphilis virus.     

De la gonorrhée à la blennorragie: Les grandes étapes historiques

This paper examines the history of gonorrhoea and its treatment. It is very probably a very ancient disease that was confused with syphilis for centuries.     

Meteorological periodicities in zonal mean annual temperatures and precipitation totals

Abstract

A long‐period data set (1880–1970) of mean annual temperatures and precipitation totals for over 100 stations worldwide distributed was used to calculate time series of zonal means at 10 degree latitude bands. Power spectra of these zonally averaged series display the following features: over most of the earth zonal mean annual temperatures undergo long‐term climatic fluctuations (≥22 years).

Trends in rainfall totals are only detected in the zones 20°‐30°N and 40°‐50°N. As reported earlier for single stations, a quasi‐triennial oscillation (3–4 years) is seen also in zonal rainfall totals at most latitude belts. No 11‐years peak was observed both in temperature and precipitation spectra. A 22‐year peak is observed at equatorial zones and in the zone 40°‐50°N.     

Aulus-Cornelius Celse (1ers. après J.-C.) : L’andrologie dans l’œuvre médicale d’un grand encyclopédiste

Knowledge in the field of andrology in the Greek-Roman period are preserved in the workDe re medica by Celsus.     

Le fondateur de la syphiligraphie Alfred Fournier (1832—1914) et sa lutte contre la syphilis

By his studies on syphilis, the creation of the first chair of syphilology, definition of syphilology as a distinct medical speciality and his prophylactic and therapeutic measures, Alfred Fournier made a major contribution to the fight against syphilis and is rightly considered to be the founder of syphilology.