Suppression if milk secretion (exocytosis) by concanavalin A in vitro

The observation that concanavalian A can inhibit milk secretion was evaluated in an in vitro system employing minced mammary gland or isolated alveoli from lactating rats. Release of milk constituents (casein, lactose and fat globules) into the medium in the presence and absence of concanavalin A was measured during 1 or 2 h incubations. The effect of concanavalin A on glucose uptake and CO₂ production of the minced tissued was also studied. Concanavalin A suppressed release of milk components at a concentration as low as 80 μg/ml of medium. Respiration of minced mammary tissue in the presence of concanavalin A (100 μg/ml of medium) was essentially the same as that of the control. The data are evidence that concanavalin A acts directly on the mammary cell in suppressing milk secretion and that the effect is not due to cytotoxicity.     

Catch me if you can: phagocytosis and killing avoidance by Cryptococcus neoformans

After inhalation of infectious particles, Cryptococcus neoformans resides in the alveolar spaces, where it can survive and replicate in the extracellular environment. This yeast has developed different mechanisms to avoid internalization by phagocytic cells, the main one being a polysaccharide capsule around the cell body, which inhibits the uptake of the yeast by macrophages. In addition, capsule-independent mechanisms have also been described, such as the production of antiphagocytic proteins. Despite these mechanisms, phagocytosis can occur in the presence of opsonins, and once C. neoformans is internalized, multiple outcomes are possible, including pathogen killing or intracellular replication and escape from macrophages. For this reason, C. neoformans is considered a facultative intracellular pathogen. As alveolar macrophages are the first component of the host immune system to confront C. neoformans, the outcome of this interaction could determine the degree of infection, producing either a severe disseminated disease or a latency state. In this review, we will tackle the complexity of the interaction between C. neoformans and macrophages, including the phagocytic avoidance mechanisms and all the possible outcomes that have been described for this interaction. Finally, we will discuss the consequences of the different outcomes for the type of infection produced in the host.     

Nature conservation as if people mattered

The restoration of natural capital is arguably one of the most radical ideas to emerge in recent years as it links two imperatives whose exponents have been at loggerheads for decades. These are the need to protect biodiversity and conserve natural resources as espoused by conservationists and environmentalists, and the demand for natural resources as dictated by economists and society at large, at local, regional, national and international scales. We need to work together, or even ‘leap together’, across traditional disciplinary frontiers or polemical stances, in order to find innovative solutions that counter the prevailing ideological divide separating economics and ecology. We close this special issue with a proposition of five pillars and three principal tasks for sustainable living, including conservation and restoration.