Carbohydrate-binding specificities of potential probiotic <Emphasis Type="Italic">Lactobacillus</Emphasis> strains in porcine jejunal (IPEC-J2) cells and porcine mucin

Bacterial lectins are carbohydrate-binding adhesins that recognize glycoreceptors in the gut mucus and epithelium of hosts. In this study, the contribution of lectin-like activities to adhesion of Lactobacillus mucosae LM1 and Lactobacillus johnsonii PF01, which were isolated from swine intestine, were compared to those of the commercial probiotic Lactobacillus rhamnosus GG. Both LM1 and PF01 strains have been reported to have good adhesion ability to crude intestinal mucus of pigs. To confirm this, we quantified their adhesion to porcine gastric mucin and intestinal porcine enterocytes isolated from the jejunum of piglets (IPEC-J2). In addition, we examined their carbohydrate-binding specificities by suspending bacterial cells in carbohydrate solutions prior to adhesion assays. We found that the selected carbohydrates affected the adherences of LM1 to IPEC-J2 cells and of LGG to mucin. In addition, compared to adhesion to IPEC-J2 cells, adhesion to mucin by both LM1 and LGG was characterized by enhanced specific recognition of glycoreceptor components such as galactose, mannose, and N-acetylglucosamine. Hydrophobic interactions might make a greater contribution to adhesion of PF01. A similar adhesin profile between a probiotic and a pathogen, suggest a correlation between shared pathogen–probiotic glycoreceptor recognition and the ability to exclude enteropathogens such as Escherichia coli K88 and Salmonella Typhimurium KCCM 40253. These findings extend our understanding of the mechanisms of the intestinal adhesion and pathogen-inhibition abilities of probiotic Lactobacillus strains.     

A process‐based model supports an association between dispersal and the prevalence of species traits in tropical reef fish assemblages

Habitat dynamics interacting with species dispersal abilities could generate gradients in species diversity and prevalence of species traits when the latter are associated with species dispersal potential. Using a process‐based model of diversification constrained by a dispersal parameter, we simulated the interplay between reef habitat dynamics during the past 140 million years and dispersal, shaping lineage diversification history and assemblage composition globally. The emerging patterns from the simulations were compared to current prevalence of species traits related to dispersal for 6315 tropical reef fish species. We found a significant spatial congruence between the prevalence of simulated low dispersal values and areas with a large proportion of species characterized by small adult body size, narrow home range mobility behaviour, pelagic larval duration shorter than 21 days and diurnal activity. Species characterized by such traits were found predominantly in the Indo‐Australian Archipelago and the Caribbean Sea. Furthermore, the frequency distribution of the dispersal parameter was found to match empirical distributions for body size, PLD and home range mobility behaviour. Also, the dispersal parameter in the simulations was associated to diversification rates and resulted in trait frequency matching empirical distributions. Overall, our findings suggest that past habitat dynamics, in conjunction with dispersal processes, influenced diversification in tropical reef fishes, which may explain the present‐day geography of species traits.     

Genome Sequence of Lactobacillus mucosae LM1, Isolated from Piglet Feces

Lactobacillus mucosae LM1, isolated from stool samples of a healthy piglet, displays good in vitro mucin adhesion and antimicrobial activity against pathogenic bacteria. To elucidate its antimicrobial effects and to find its epithelial cell and mucin adhesion genes, the genomic sequence of L. mucosae LM1 was investigated.     

Niche shift can impair the ability to predict invasion risk in the marine realm: an illustration using Mediterranean fish invaders

Climatic niche conservatism, the tendency of species‐climate associations to remain unchanged across space and time, is pivotal for forecasting the spread of invasive species and biodiversity changes. Indeed, it represents one of the key assumptions underlying species distribution models (SDMs), the main tool currently available for predicting range shifts of species. However, to date, no comprehensive assessment of niche conservatism is available for the marine realm. We use the invasion by Indo‐Pacific tropical fishes into the Mediterranean Sea, the world's most invaded marine basin, to examine the conservatism of the climatic niche. We show that tropical invaders may spread far beyond their native niches and that SDMs do not predict their new distributions better than null models. Our results suggest that SDMs may underestimate the potential spread of invasive species and call for prudence in employing these models in order to forecast species invasion and their response to environmental change.     

Responses of coral reef fishes to past climate changes are related to life‐history traits

Coral reefs and their associated fauna are largely impacted by ongoing climate change. Unravelling species responses to past climatic variations might provide clues on the consequence of ongoing changes. Here, we tested the relationship between changes in sea surface temperature and sea levels during the Quaternary and present‐day distributions of coral reef fish species. We investigated whether species‐specific responses are associated with life‐history traits. We collected a database of coral reef fish distribution together with life‐history traits for the Indo‐Pacific Ocean. We ran species distribution models (SDMs) on 3,725 tropical reef fish species using contemporary environmental factors together with a variable describing isolation from stable coral reef areas during the Quaternary. We quantified the variance explained independently by isolation from stable areas in the SDMs and related it to a set of species traits including body size and mobility. The variance purely explained by isolation from stable coral reef areas on the distribution of extant coral reef fish species largely varied across species. We observed a triangular relationship between the contribution of isolation from stable areas in the SDMs and body size. Species, whose distribution is more associated with historical changes, occurred predominantly in the Indo‐Australian archipelago, where the mean size of fish assemblages is the lowest. Our results suggest that the legacy of habitat changes of the Quaternary is still detectable in the extant distribution of many fish species, especially those with small body size and the most sedentary. Because they were the least able to colonize distant habitats in the past, fish species with smaller body size might have the most pronounced lags in tracking ongoing climate change.     

Conserving Biodiversity in a Human-Dominated World: Degradation of Marine Sessile Communities within a Protected Area with Conflicting Human Uses

Conservation research aims at understanding whether present protection schemes are adequate for the maintenance of ecosystems structure and function across time. We evaluated long-term variation in rocky reef communities by comparing sites surveyed in 1993 and again in 2008. This research took place in Tigullio Gulf, an emblematic case study where various conservation measures, including a marine protected area, have been implemented to manage multiple human uses. Contrary to our prediction that protection should have favored ecosystem stability, we found that communities subjected to conservation measures (especially within the marine protected area) exhibited the greatest variation toward architectural complexity loss. Between 1993 and 2008, chronic anthropogenic pressures (especially organic load) that had already altered unprotected sites in 1993 expanded their influence into protected areas. This expansion of human pressure likely explains our observed changes in the benthic communities. Our results suggest that adaptive ecosystem-based management (EBM), that is management taking into account human interactions, informed by continuous monitoring, is needed in order to attempt reversing the current trend towards less architecturally complex communities. Protected areas are not sufficient to stop ecosystem alteration by pressures coming from outside. Monitoring, and consequent management actions, should therefore extend to cover the relevant scales of those pressures.     

Long-term potential for tropical-forest degradation due to deforestation and fires in the Brazilian Amazon

Biome models of the global climate-vegetation relationships indicate that most of the Brazilian Amazon has potential for being covered by tropical forests. From current land-use processes observed in the region, however, substantial deforestation and fire activity have been verified in large portions of the region, particularly along the Arc of Deforestation. In a first attempt to evaluate the long-term potential for tropical-forest degradation due to deforestation and fires in the Brazilian Amazon, we analysed large-scale data on fire activity and climate factors that drive the distribution of tropical forests in the region. The initial analyses and results from this study lead to important details on the relations between these quantities and have important implications for building future parameterizations of the vulnerability of tropical forests in the region.