Utilisation of Mucin Glycans by the Human Gut Symbiont Ruminococcus gnavus Is Strain-Dependent

Commensal bacteria often have an especially rich source of glycan-degrading enzymes which allow them to utilize undigested carbohydrates from the food or the host. The species Ruminococcus gnavus is present in the digestive tract of ≥90% of humans and has been implicated in gut-related diseases such as inflammatory bowel diseases (IBD). Here we analysed the ability of two R. gnavus human strains, E1 and ATCC 29149, to utilize host glycans. We showed that although both strains could assimilate mucin monosaccharides, only R. gnavus ATCC 29149 was able to grow on mucin as a sole carbon source. Comparative genomic analysis of the two R. gnavus strains highlighted potential clusters and glycoside hydrolases (GHs) responsible for the breakdown and utilization of mucin-derived glycans. Transcriptomic and functional activity assays confirmed the importance of specific GH33 sialidase, and GH29 and GH95 fucosidases in the mucin utilisation pathway. Notably, we uncovered a novel pathway by which R. gnavus ATCC 29149 utilises sialic acid from sialylated substrates. Our results also demonstrated the ability of R. gnavus ATCC 29149 to produce propanol and propionate as the end products of metabolism when grown on mucin and fucosylated glycans. These new findings provide molecular insights into the strain-specificity of R. gnavus adaptation to the gut environment advancing our understanding of the role of gut commensals in health and disease

Yield and Economic Performance of Organic and Conventional Cotton-Based Farming Systems – Results from a Field Trial in India

The debate on the relative benefits of conventional and organic farming systems has in recent time gained significant interest. So far, global agricultural development has focused on increased productivity rather than on a holistic natural resource management for food security. Thus, developing more sustainable farming practices on a large scale is of utmost importance. However, information concerning the performance of farming systems under organic and conventional management in tropical and subtropical regions is scarce. This study presents agronomic and economic data from the conversion phase (2007–2010) of a farming systems comparison trial on a Vertisol soil in Madhya Pradesh, central India. A cotton-soybean-wheat crop rotation under biodynamic, organic and conventional (with and without Bt cotton) management was investigated. We observed a significant yield gap between organic and conventional farming systems in the 1st crop cycle (cycle 1: 2007–2008) for cotton (229%) and wheat (227%), whereas in the 2nd crop cycle (cycle 2: 2009–2010) cotton and wheat yields were similar in all farming systems due to lower yields in the conventional systems. In contrast, organic soybean (a nitrogen fixing leguminous plant) yields were marginally lower than conventional yields (21% in cycle 1, 211% in cycle 2). Averaged across all crops, conventional farming systems achieved significantly higher gross margins in cycle 1 (+29%), whereas in cycle 2 gross margins in organic farming systems were significantly higher (+25%) due to lower variable production costs but similar yields. Soybean gross margin was significantly higher in the organic system (+11%) across the four harvest years compared to the conventional systems. Our results suggest that organic soybean production is a viable option for smallholder farmers under the prevailing semi-arid conditions in India. Future research needs to elucidate the long-term productivity and profitability, particularly of cotton and wheat, and the ecological impact of the different farming systems

Discovery of intramolecular trans-sialidases in human gut microbiota suggests novel mechanisms of mucosal adaptation

The gastrointestinal mucus layer is colonized by a dense community of microbes catabolizing dietary and host carbohydrates during their expansion in the gut. Alterations in mucosal carbohydrate availability impact on the composition of microbial species. Ruminococcus gnavus is a commensal anaerobe present in the gastrointestinal tract of > 90% of humans and overrepresented in inflammatory bowel diseases (IBD). Using a combination of genomics, enzymology and crystallography, we show that the mucin-degrader R. gnavus ATCC 29149 strain produces an intramolecular trans-sialidase (IT-sialidase) that cleaves off terminal alpha 2-3-linked sialic acid from glycoproteins, releasing 2,7-anhydro-Neu5Ac instead of sialic acid. Evidence of IT-sialidases in human metagenomes indicates that this enzyme occurs in healthy subjects but is more prevalent in IBD metagenomes. Our results uncover a previously unrecognized enzymatic activity in the gut microbiota, which may contribute to the adaptation of intestinal bacteria to the mucosal environment in health and disease.Peer reviewe

Can rigorous impact evaluations improve humanitarian assistance?

Each year billions of US-dollars of humanitarian assistance are mobilised in response to man-made emergencies and natural disasters. Yet, rigorous evidence for how best to intervene remains scant. This dearth reflects that rigorous impact evaluations of humanitarian assistance pose major methodological, practical and ethical challenges. While theory-based impact evaluations can crucially inform humanitarian programming, popular methods, such as orthodox RCTs, are less suitable. Instead, factorial designs and quasi-experimental designs can be ethical and robust, answering questions about how to improve the delivery of assistance. We argue that it helps to be prepared, planning impact evaluations before the onset of emergencies

Reducing Binge Drinking? The Effect of a Ban on Late-Night Off-Premise Alcohol Sales on Alcohol-Related Hospital Stays in Germany

Excessive alcohol consumption among young people is a major public health concern. On March 1, 2010, the German state of Baden-Württemberg banned the sale of alcoholic beverages between 10pm and 5am at off-premise outlets (e.g., gas stations, kiosks, supermarkets). We use rich monthly administrative data from a 70 percent random sample of all hospitalizations during the years 2007-2011 in Germany in order to evaluate the short-term impact of this policy on alcohol-related hospitalizations. Applying difference-in-differences methods, we find that the policy change reduces alcohol-related hospitalizations among adolescents and young adults by about seven percent. There is also evidence of a decrease in the number of hospitalizations due to violent assault as a result of the ban

Transgenic Crops, Production Risk, and Agrobiodiversity

Do transgenic crops cause agrobiodiversity erosion? We hypothesize that they increase productivity and reduce production risk and may therefore reduce farmer demand for onfarm varietal diversity, especially when only a few transgenic varieties are available. We also hypothesize that varietal diversity can be preserved when more transgenic varieties are supplied. These hypotheses are tested and confirmed with panel data for the case of transgenic cotton in India. Cotton varietal diversity in India, with of over 90% adoption of transgenic technology, is now at the same level than it was before the introduction of this technology. Some policy implications are discussed

Unemployment: The Silent Epidemic

This paper examines two key aspects of unemployment-its propagation mechanism and socioeconomic costs. It identifies a key feature of this macroeconomic phenomenon: it behaves like a disease. A detailed assessment of the transmission mechanism and the existing pecuniary and nonpecuniary costs of unemployment suggests a fundamental shift in the policy responses to tackling joblessness. To stem the contagion effect and its outsized social and economic impact, fiscal policy can be designed around two criteria for successful disease intervention-preparedness and prevention. The paper examines how a job guarantee proposal uniquely meets those two requirements. It is a policy response whose merits include much more than its macroeconomic stabilization features, as discussed in the literature. It is, in a sense, a method of inoculation against the vile effects of unemployment. The paper discusses several preventative features of the program

Top-Down vs. Bottom-Up: The Long-Term Impact of Government Ideology and Personal Experience on Values

This paper studies the long-term impact of societal socialization on values using the example of doping behavior in sports. We apply the German Reunification Approach to the microcosm of Berlin and exploit its 40-year long division into a capitalist and a communist sector. We deliberately chose attitudes toward doping to test the impact of ideology on values since (i) post-1989 disappointed economic hopes did not confound doping attitudes, and because of (ii) the systematic GDR state doping activities that became public in reunified Germany in the 1990s. Our findings demonstrate that even after half the time the division lasted, e.g. 20 years after the reunification, differences in convictions continue to persist. Personal extramural sports experience and age are equally strong predictors of individual attitudes and beliefs, especially in interaction with ideological socialization