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Holistic emerging approaches allow us to understand that every organism is the result of integration mechanisms observed at every level of nature: integration of DNA from virus and bacteria in metazoans, endosymbiotic relationships and holobionts. Horizontal gene transfer events in Bacteria, Archaea and Eukaryotes have resulted in the chimeric nature of genomes. As a continuity of this genomic landscape, the human body contains more bacterial than human cells. Human microbiome has co-evolved with the human being as a unity called holobiont. The loss of part of our microbiome along evolution can explain the continuous increasing incidence of immune and inflammatory-related diseases. Life is a continuous process in which the organism experiences its environment and this interaction impacts in the epigenetic system and the genomic structure. The emerging perspectives restitute the great importance of Lamarck's theoretical contributions (the milieu) and Darwin's pangenesis theory.

Bacteriocins produced by lactic acid bacteria are gaining increased importance due to their activity against undesirable microorganisms in foods. In this study, a concentrated acid extract of a culture of Lactobacillus sakei subsp. sakei 2a, a bacteriocinogenic strain isolated from a Brazilian pork product, was purified by cation exchange and reversed-phase chromatographic methods. The amino acid sequences of the active antimicrobial compounds determined by Edman degradation were compared to known protein sequences using the BLAST-P software. Three different antimicrobial compounds were obtained, P1, P2 and P3, and mass spectrometry indicated molecular masses of 4.4, 6.8 and 9.5 kDa, respectively. P1 corresponds to classical sakacin P, P2 is identical to the 30S ribosomal protein S21 of L. sakei subsp. sakei 23 K, and P3 is identical to a histone-like DNA-binding protein HV produced by L. sakei subsp. sakei 23 K. Total genomic DNA was extracted and used as target DNA for PCR amplification of the genes sak, lis and his involved in the synthesis of P1, P2 and P3. The fragments were cloned in pET28b expression vector and the resulting plasmids transformed in E. coli KRX competent cells. The transformants were active against Listeria monocytogenes, indicating that the activity of the classical sakacin P produced by L. sakei 2a can be complemented by other antimicrobial proteins.

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The study of the human microbiome or community of microorganisms and collection of genomes found in the human body is one of the fastest growing research areas because many diseases are reported to be associated with microbiome imbalance or dysbiosis. With the improvement in novel sequencing techniques, researchers are now generating millions of sequences of different sites from the human body and evaluating specific differences in microbial communities. The importance of microbiome constituency is so relevant that several consortia like the Human Microbiome project (HMP) and Metagenomics of the Human Intestinal Tract (MetaHIT) project are focusing mainly on the human microbiome. The aim of this review is to highlight points of research in this field, mainly focusing on particular factors that modulate the microbiome and important insights into its potential impact on our health and well-being.

A 15-mer peptide derived from enterocin CRL35 inhibited the growth of L. innocua and Listeria monocytogenes in synthetic/minimal media and dissipated the membrane potential of sensitive cells, with MICs of 10 and 50 microM, respectively. 15-mer derivatives from other class IIa bacteriocins (mesentericin Y105, pediocin PA-1 and piscicolin 126) also showed antimicrobial activities.