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Long-term vegetarian diet contributed to quantity and associated bacterial community shifts in fecal microbiota composition. Consumption of foods of animal origin (eggs, red meat, white meat, milk, yoghurt, other dairy products, fish and seafood) and vegetarian type of diet explained the largest share of variance in microbial community structure. Fecal microbiota composition was also associated with participants' age, gender and body mass.

Intracellular bacteria were observed in the hepatopancreas of the terrestrial isopod Porcellio scaber. Comparative 16S rRNA gene sequence analysis and electron microscopic observations were used to determine the taxonomic position of these intracellular bacteria. Phylogenetic analysis and a complex developmental cycle affiliate these bacteria to the order Chlamydiales, within which they form a distinctive lineage, close to the family Simkaniaceae. They share <92 % 16S rRNA gene sequence similarity with their closest relative and <88 % similarity with other members of the order Chlamydiales. A specific signature oligonucleotide sequence was identified and used as a probe, enabling the identification of intracellular bacteria in infected hepatopancreatic tissue. According to the distinctive morphology of their elementary bodies, which are rod-shaped rather than spherical and contain translucent oblong structures, their genomic properties and their crustacean host, the name ‘Candidatus Rhabdochlamydia porcellionis' is proposed for intracellular bacteria in the hepatopancreas of P. scaber.

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Pointed, rod-shaped bacteria colonizing the cuticular surface of the hindgut of the terrestrial isopod crustacean Porcellio scaber (Crustacea: Isopoda) were investigated by comparative 16S rRNA gene sequence analysis and electron microscopy. The results of phylogenetic analysis, and the absence of a cell wall, affiliated these bacteria with the class Mollicutes, within which they represent a novel and deeply branched lineage, sharing less than 82.6% sequence similarity to known Mollicutes. The lineage has been positioned as a sister group to the clade comprising the Spiroplasma group, the Mycoplasma pneumoniae group, and the Mycoplasma hominis group. The specific signature sequence was identified and used as a probe in in situ hybridization, which confirmed that the retrieved sequences originate from the attached rod-shaped bacteria from the hindgut of P. scaber and made it possible to detect these bacteria in their natural environment. Scanning and transmission electron microscopy revealed a spherically shaped structure at the tapered end of the rod-shaped bacteria, enabling their specific and exclusive attachment to the tip of the cuticular spines on the inner surface of the gut. Specific adaptation to the gut environment, as well as phylogenetic positioning, indicate the long-term association and probable coevolution of the bacteria and the host. Taking into account their pointed, rod-shaped morphology and their phylogenetic position, the name "Candidatus Bacilloplasma" has been proposed for this new lineage of bacteria specifically associated with the gut surface of P. scaber.The common woodlouse Porcellio scaber is a widely spread species of the terrestrial isopod crustaceans (Crustacea, Isopoda, Oniscidea) living in temperate climates. Like other terrestrial isopods, P. scaber is a herbivorous scavenger, feeding predominantly on decayed plant material and thus contributing to nutrient and energy cycling in terrestrial ecosystems (43). Due to its ecological importance, easy handling, breeding capability under laboratory conditions, and tolerance to polluted environments as well as the considerable body of knowledge about its biology, this crustacean is commonly used as a test organism in terrestrial ecotoxicological and ecophysiological studies (12,17).The tripartite digestive system of P. scaber consists of a short foregut comprising an esophagus and stomach, a midgut consisting of two pairs of blind-ended tubular digestive glands, and a long, tube-like hindgut. The last of these comprises two functionally different parts, an anterior chamber and a papillate region with a rectum (17). The foregut of terrestrial isopods is generally poorly inhabited by microorganisms. On the other hand, a high microbial density is found in the hindgut, particularly in the papillate region, where favorable conditions (44) allow the multiplication of those microorganisms that have survived the digestion in the anterior part of the digestive tract of P. scaber (24, 26) and those of other terrestrial isopods like Oniscus asellu...