Closely related Lak megaphages replicate in the microbiomes of diverse animals.

Lak phages with alternatively coded ∼540 kbp genomes were recently reported to replicate in Prevotella in microbiomes of humans that consume a non-Western diet, baboons, and pigs. Here, we explore Lak phage diversity and broader distribution using diagnostic polymerase chain reaction and genome-resolved metagenomics. Lak phages were detected in 13 animal types, including reptiles, and are particularly prevalent in pigs. Tracking Lak through the pig gastrointestinal tract revealed significant enrichment in the hindgut compared to the foregut. We reconstructed 34 new Lak genomes, including six curated complete genomes, all of which are alternatively coded. An anomalously large (∼660 kbp) complete genome reconstructed for the most deeply branched Lak from a horse microbiome is also alternatively coded. From the Lak genomes, we identified proteins associated with specific animal species; notably, most have no functional predictions. The presence of closely related Lak phages in diverse animals indicates facile distribution coupled to host-specific adaptation.

Application of DNA Barcoding for Controlling of the Species from Octopus Genus.

The DNA barcoding proposes the use of a particular sequence from a single genomic region as the base for an identifying system capable to determine all animal species. This methodology comprises the analysis of a 655 base-pair region from the mithocondrial cytochrome C oxidase gene (COI). Its application in the species identification of fishery products has been very promising. However, in the last years some doubts about its usage have emerged. In this work, we make use of the DNA barcoding for the identification of some of the octopus species with higher commercial interest (Octopus membranaceus, Octopus vulgaris, Octopus aegina, Octopus cyanea) focusing the attention on the reliability and completeness of the available information on the databases. The study looked over 51 individuals apparently belonging to the Octopus genus. For the identification of O.aegina, O.cyanea, O.vulgaris species no particular problems were found. On the other hand, most of the samples of O.membranaceus, though they clearly presented the morphological characteristics of the species, were not identified with the biomolecular analyses.