Climate change goes underground: effects of elevated atmospheric CO2 on microbial community structure and activities in the rhizosphere.

General concern about climate change has led to growing interest in the responses of terrestrial ecosystems to elevated concentrations of CO2 in the atmosphere. Experimentation during the last two to three decades using a large variety of approaches has provided sufficient information to conclude that enrichment of atmospheric CO2 may have severe impact on terrestrial ecosystems. This impact is mainly due to the changes in the organic C dynamics as a result of the effects of elevated CO2 on the primary source of organic C in soil, i.e., plant photosynthesis. As the majority of life in soil is heterotrophic and dependent on the input of plant-derived organic C, the activity and functioning of soil organisms will greatly be influenced by changes in the atmospheric CO2 concentration. In this review, we examine the current state of the art with respect to effects of elevated atmospheric CO2 on soil microbial communities, with a focus on microbial community structure. On the basis of the existing information, we conclude that the main effects of elevated atmospheric CO2 on soil microbiota occur via plant metabolism and root secretion, especially in C3 plants, thereby directly affecting the mycorrhizal, bacterial, and fungal communities in the close vicinity of the root. There is little or no direct effect on the microbial community of the bulk soil. In particular, we have explored the impact of these changes on rhizosphere interactions and ecosystem processes, including food web interactions

Antibiotics in the clinical pipeline in 2013

The continued emergence of multi-drug-resistant bacteria is a major public health concern. The identification and development of new antibiotics, especially those with new modes of action, is imperative to help treat these infections. This review lists the 22 new antibiotics launched since 2000 and details the two first-in-class antibiotics, fidaxomicin (1) and bedaquiline (2), launched in 2011 and 2012, respectively. The development status, mode of action, spectra of activity, historical discovery and origin of the drug pharmacophore (natural product, natural product derived, synthetic or protein/mammalian peptide) of the 49 compounds and 6 β-lactamase/β-lactam combinations in active clinical development are discussed, as well as compounds that have been discontinued from clinical development since 2011. New antibacterial pharmacophore templates are also reviewed and analyzed