27 research outputs found
Assessment of pollution risk ascribed to Santa Margarida Military Camp activities (Portugal)
Santa Margarida Military Camp (S.M.M.C.) is
the only one Portuguese military training area, including
firing ranges for tactical military manoeuvres of mechanised
divisions. For this reason, various negative effects on
the environment were expected due to the military activities,
as the Military Camp’s area is classified as a high
vulnerability area to pollution of its multilayer porous
aquifers. The aim of this study was to identify and characterise
local/regional geochemical impacts caused by the
continuing military training activities performed at
S.M.M.C. in the course of 52 years. An overview of the
geochemical research issues as a basis for risk assessment
is presented. A special attention has been put on the
quality of local and regional surface waters, shallow
groundwaters and groundwaters. Local soils and sediments
as well as fragments of shells and bullets were sampled
and analysed. The results so far obtained, indicated that none pollution effects were a consequence of the military
training activities. Till now, the geochemical signatures
such as, high levels of K, Cl and NO3 in waters, detected
in particular sites, should be faced as tracers of diffuse
pollution ascribed to urban waste disposal and cattle
breading
Direct Visualization by Cryo-EM of the Mycobacterial Capsular Layer: A Labile Structure Containing ESX-1-Secreted Proteins
The cell envelope of mycobacteria, a group of Gram positive bacteria, is composed of a plasma membrane and a Gram-negative-like outer membrane containing mycolic acids. In addition, the surface of the mycobacteria is coated with an ill-characterized layer of extractable, non-covalently linked glycans, lipids and proteins, collectively known as the capsule, whose occurrence is a matter of debate. By using plunge freezing cryo-electron microscopy technique, we were able to show that pathogenic mycobacteria produce a thick capsule, only present when the cells were grown under unperturbed conditions and easily removed by mild detergents. This detergent-labile capsule layer contains arabinomannan, α-glucan and oligomannosyl-capped glycolipids. Further immunogenic and proteomic analyses revealed that Mycobacterium marinum capsule contains high amounts of proteins that are secreted via the ESX-1 pathway. Finally, cell infection experiments demonstrated the importance of the capsule for binding to cells and dampening of pro-inflammatory cytokine response. Together, these results show a direct visualization of the mycobacterial capsular layer as a labile structure that contains ESX-1-secreted proteins