When noisy neighbors are a blessing: analysis of gene expression noise identifies coregulated genes

In this issue of Molecular Cell, Stewart-Ornstein et?al. (2012) use systematic pair-wise correlation analysis of expression noise in a large number of yeast genes to identify clusters of functionally related genes and signaling pathways responsible for elevated noise.     

Common alien plants are more competitive than rare natives but not than common natives

Success of alien plants is often attributed to high competitive ability. However, not all aliens become dominant, and not all natives are vulnerable to competitive exclusion. Here, we quantified competitive outcomes and their determinants, using response‐surface experiments, in 48 pairs of native and naturalised alien annuals that are common or rare in Germany. Overall, aliens were not more competitive than natives. However, common aliens (invasive) were, despite strong limitation by intraspecific competition, more competitive than rare natives. This is because alien species had higher intrinsic growth rates than natives, and common species had higher intrinsic growth rates than rare ones. Strength of interspecific competition was not related to status or commonness. Our work highlights the importance of including commonness in understanding invasion success. It suggests that variation among species in intrinsic growth rates is more important in competitive outcomes than inter‐ or intraspecific competition, and thus contributes to invasion success and rarity.     

Widespread plant species: natives versus aliens in our changing world

Estimates of the level of invasion for a region are traditionally based on relative numbers of native and alien species. However, alien species differ dramatically in the size of their invasive ranges. Here we present the first study to quantify the level of invasion for several regions of the world in terms of the most widely distributed plant species (natives vs. aliens). Aliens accounted for 51.3% of the 120 most widely distributed plant species in North America, 43.3% in New South Wales (Australia), 34.2% in Chile, 29.7% in Argentina, and 22.5% in the Republic of South Africa. However, Europe had only 1% of alien species among the most widespread species of the flora. Across regions, alien species relative to native species were either as well-distributed (10 comparisons) or more widely distributed (5 comparisons). These striking patterns highlight the profound contribution that widespread invasive alien plants make to floristic dominance patterns across different regions. Many of the most widespread species are alien plants, and, in particular, Europe and Asia appear as major contributors to the homogenization of the floras in the Americas. We recommend that spatial extent of invasion should be explicitly incorporated in assessments of invasibility, globalization, and risk assessments.     

Return of the natives

A new study reveals that some declining native species could win back against the competition from invading exotics. Nigel Williams reports.     

Cell interactome: Good neighbors or bad neighbors

We report an interesting finding that cellular distribution and interactions between neighboring cells modulate protein expression and localization. MCF7 breast cancer cells, which express ERb, were cultured in estrogen-free medium. ERb exhibited a unique migration pattern that was dependent on cell density and proximity. This finding attests to a novel interaction mechanism other than receptor–to–ligand. Since cells were grown in conditioned culture media, the only factor influencing protein distribution is cell–cell proximity (cell–cell interactions). Thus, hormonal receptors may function independently from their ligand. In addition, physical intercellular interactions may function as a non-molecular factor inducing gene expression and activation.