Community composition and the environment modulate the population dynamics of type VI secretion in human gut bacteria.

Understanding the relationship between the composition of the human gut microbiota and the ecological forces shaping it is of great importance; however, knowledge of the biogeographical and ecological relationships between physically interacting taxa is limited. Interbacterial antagonism may play an important role in gut community dynamics, yet the conditions under which antagonistic behaviour is favoured or disfavoured by selection in the gut are not well understood. Here, using genomics, we show that a species-specific type VI secretion system (T6SS) repeatedly acquires inactivating mutations in Bacteroides fragilis in the human gut.

Community composition and the environment modulate the population dynamics of type VI secretion in human gut bacteria.

Understanding the relationship between the composition of the human gut microbiota and the ecological forces shaping it is of high importance as progress towards therapeutic modulation of the microbiota advances. However, given the inaccessibility of the gastrointestinal tract, our knowledge of the biogeographical and ecological relationships between physically interacting taxa has been limited to date. It has been suggested that interbacterial antagonism plays an important role in gut community dynamics, but in practice the conditions under which antagonistic behavior is favored or disfavored by selection in the gut environment are not well known.

Application of Nucleic Acid-Based Strategies to Detect Infectious Pathogens in Orthopaedic Implant-Related Infection.

➤: Implant-associated infection in orthopaedic surgery remains an enormous and largely unsolved clinical problem with a high rate of persistent or recurrent infection. This may be due, at least in part, to the potential for underdiagnosis by traditional microbial culture or the potential for culture to incompletely identify the microbial species present.

➤: Nucleic acid-based diagnostic techniques, focused on using the diagnostic information contained in DNA or RNA to identify microbial species, have been developing rapidly and have garnered escalating interest for both clinical and research applications.

Detecting Flavobacterial Fish Pathogens in the Environment via High-Throughput Community Analysis.

Diseases caused by the fish pathogens Flavobacterium columnare and Flavobacterium psychrophilum are major contributors of preventable losses in the aquaculture industry. The persistent and difficult-to-control infections caused by these bacteria make timely intervention and prophylactic elimination of pathogen reservoirs important measures to combat these disease-causing agents. In this study, we present two independent assays for detecting these pathogens in a range of environmental samples.

: Old World Leech Gut Microbial Community Structure Conserved in a New World Leech.

Leeches are found in terrestrial, aquatic, and marine habitats on all continents. Sanguivorous leeches have been used in medicine for millennia. Modern scientific uses include studies of neurons, anticoagulants, and gut microbial symbioses.

Role of Gut Microbiota and Short Chain Fatty Acids in Modulating Energy Harvest and Fat Partitioning in Youth.

Objective: We aimed at determining the relationship of the gut microbiota and short chain fatty acids with obesity and fat partitioning and at testing potential differences in the ability of gut microbiota to ferment equal amounts of carbohydrates (CHO) between lean and obese youth.

Research Design And Methods: We analyzed the gut microbiota of 84 youth in whom body fat distribution was measured by fast-magnetic resonance imaging, de novo lipogenesis (DNL) quantitated using deuterated water, and the capability of gut flora to ferment CHO was assessed by C-fructose treatment in vitro.

Results: A significant association was found between the Firmicutes to Bacteroidetes ratio, and the abundance of Bacteroidetes and Actinobacteria with body mass index, visceral and SC fat (all P < .

Metagenomic analysis of the medicinal leech gut microbiota.

There are trillions of microbes found throughout the human body and they exceed the number of eukaryotic cells by 10-fold. Metagenomic studies have revealed that the majority of these microbes are found within the gut, playing an important role in the host's digestion and nutrition. The complexity of the animal digestive tract, unculturable microbes, and the lack of genetic tools for most culturable microbes make it challenging to explore the nature of these microbial interactions within this niche.