The seven contributions of this Frontiers in Life Science issue span the whole scale of biology, from molecules to organisms, and address very different (but connected) subjects, from nature to culture.
Tea (black and green) is a very popular beverage across the world. Made from fermented leaves of Camellia sinensis, it has a high content of phenolic compounds which contribute to its reputation as a healthy beverage. The antioxidative properties of these compounds are manifested particularly by their abilities to scavenge existing free radicals and inhibit the generation of new ones. The work by Shalaby et al. aimed to evaluate the mode of action of polyphenolic compounds and their potential interaction with sweeteners. The authors conclude that, while there were no significant interactions with the aspartame, addition of table sugar (sucrose) had an effect, surprisingly in opposite directions, increasing/decreasing the antioxidant activity of black/green tea, respectively. Think about it next time you hesitate to put some sugar in your tea!
Going to microbiology and ecological issues, Tharali et al. provide a nice overview of a microbial fuel cell, a device that converts chemical energy released during the metabolism of some micro-organisms into electrical energy. This bioelectricity production from microbes could prove a valuable source of green energy, minimizing the utilization of fossil fuels. At the same time, anaerobic digestion by bacteria of waste products, pollutants and chemicals can prove to be an effective way of cleaning the environment. As concluded by the authors, we have now to work on the best technological solutions to exploit this double benefit offered by micro-organisms.
We then move to the mangroves, intertidal zones between land and sea of tropical and sub-tropical regions of the world where diverse halophytic plant communities are found. Thatoi et al. provide an in-depth review of the diversity and distribution of different species of genus Avicennia and discuss their medicinal uses. As stressed by the authors, there is a need for a detailed analysis of phytochemical and pharmacological properties of the species found in the large mangrove vegetal biodiversity in an effort to establish their medicinal importance and therapeutic potential (if any), opening perspectives for future drug development.
Further investigating traditional knowledge and health issues, we move to fermentation, an old and world-wide method for development of a diversity of aromas, flavors and textures as well as for the preservation and biological enrichment of food by manipulation of different endogenous microbial populations. All regions in the world have developed their own unique substrates and preparation methods for fermented products. Das et al. focus on the Seven Sister states of northeast India, in which mainly soybeans, bamboo shoots and other locally available vegetables are commonly fermented. More generally, this review shows that a basic understanding about the relationship between food, its potential transformation by micro-organisms and health of the human being is important to improve the quality of food as well as prevention of several diseases.
To further illustrate micro-organisms' importance in our environment, the next contribution addresses the role of bacteria in agriculture. Wheat being the third-most cultivated cereal after maize and rice, development of methods to increase crop yield are of utmost importance in the context of rapid human population growth. By comparing plant growth, promoting phylloplane bacteria of three commercially popular wheat varieties, Batool et al. demonstrate that the phyllosphere microbial community exhibits beneficial properties for the plants' yield.
Moving to health issues, the review by Mishra et al. investigates metastasis, a process which involves the spreading and proliferation of a tumour to distant parts of the body from its original site. In this paper, the authors describe some important actors, factors, steps and pathways that occur during the colonization of tumoural cells at these distant areas. This knowledge is obviously a prerequisite to develop therapeutics that would target the pathways involved.
For the last paper, we move to an in-depth discussion about one of the most fundamental issues in modern biology. The historical concept of epigenetics essentially refers to cell differentiation, as ‘the process through which the genotype gives rise to the phenotype’, as proposed by the embryologist and geneticist Conrad Hal Waddington. It is recognized today that interactions between the environment and the DNA through modifications of chromatin are not only responsible for the expression of a normal phenotype but are also involved in the development of various pathologies. As emphasized by Villota-Salazar et al. in their review, the epigenome as the bridge between the genome and the phenotype is no doubt one of the most interesting current ideas in biology and may change our notions about inheritance and evolution.
We hope the reader will enjoy reading these various contributions, which span very diverse aspects of life science and provide good sources of reflection about nutrition, health, ecology and evolution issues.