Polyphenols constitute one of the most common groups of substances in plants. Polyphenolic compounds have been reported to have a wide range of biological activities, many of which are related to their conventional antioxidant action; however, increasing scientific knowledge has highlighted their potential activity in preventing oral disease, including the prevention of tooth decay. The aim of this review is to show the emerging findings on the anti-cariogenic properties of polyphenols, which have been obtained from several in vitro studies investigating the effects of these bioactive molecules against Streptococcus mutans, as well as in vivo studies. The analysis of the literature supports the anti-bacterial role of polyphenols on cariogenic streptococci, suggesting (1) a direct effect against S. mutans; (2) an interaction with microbial membrane proteins inhibiting the adherence of bacterial cells to the tooth surface; and (3) the inhibition of glucosyl transferase and amylase. However, more studies, particularly in vivo and in situ, are necessary to establish conclusive evidence for the effectiveness and the clinical applications of these compounds in the prevention of dental caries. It is essential to better determine the nature and distribution of these compounds in our diet and to identify which of the hundreds of existing polyphenols are likely to provide the greatest effects.

The possibility of applying main AOP techniques, namely ozonation, H₂O₂/UV photolysis and TiO₂ photocatalysis to provide a significant reduction of toxicity of pharmaceutical mixtures has been evaluated. For the preparation of the mixture six pharmaceuticals were chosen among those found at highest concentrations in Sewage Treatment Plant effluents, namely carbamazepine, clofibric acid, diclofenac, sulfamethoxazole, ofloxacin and propranolol. The blue-green alga Synechococcus leopoliensis and the rotifer Brachyonus calyciflorus were utilised to assess the toxicity of the mixtures after AOP treatments. All the toxicity tests were performed using chronic standardized bioassays. The best results were obtained with ozonation. With this type of treatment a complete removal of mixture toxicity on S. leopolensis was obtained even after the shortest time of application (1 min). The ozonation treatment leads also to removal of all the pharmaceutical mixture toxicity on B. calyciflorus, by applying the oxidizing agent for at least for 2 minutes.

Stevia rebaudiana Bertoni is a small perennial shrub of the Asteraceae (Compositae) family that is native to South America, particularly Brazil and Paraguay, where it is known as “stevia” or “honey leaf” for its powerful sweetness. Several studies have suggested that in addition to their sweetness, steviosides and their related compounds, including rebaudioside A and isosteviol, may offer additional therapeutic benefits. These benefits include anti-hyperglycaemic, anti-hypertensive, anti-inflammatory, anti-tumor, anti-diarrheal, diuretic, and immunomodulatory actions. Additionally, critical analysis of the literature supports the anti-bacterial role of steviosides on oral bacteria flora. The aim of this review is to show the emerging results regarding the anti-cariogenic properties of S. rebaudiana Bertoni. Data shown in the present paper provide evidence that stevioside extracts from S. rebaudiana are not cariogenic. Future research should be focused on in vivo studies to evaluate the effects on dental caries of regular consumption of S. rebaudiana extract-based products.

The biosynthesis of poly-β-hydroxybutyrate (PHB) directly from carbon dioxide is a sustainable alternative for non-renewable, petroleum-based polymer production. Synechocystis sp. PCC6803 can naturally accumulate PHB using CO2 as the sole carbon source, particularly when major nutrients such as nitrogen become limiting. Many previous studies have tried to genetically engineer PHB overproduction; mostly by increasing the expression of enzymes directly involved in its biosynthesis pathway. Here, we have instead concentrated on engineering the central carbon metabolism of Synechocystis such that (i) the PHB synthesis pathway becomes deregulated, and/or (ii) the levels of its substrate, acetyl-CoA, were increased. Seven different mutants were constructed harboring, separately or in combination, three different genetic modifications to Synechocystis' metabolic network. These were the deletions of phosphotransacetylase (Pta) and acetyl-CoA hydrolase (Ach), and the expression of a heterologous phosphoketolase (XfpK) from Bifidobacterium breve. The wild type Synechocystis and the derivative strains were compared in terms of biomass and the PHB production capability during photoautotrophic growth. This was performed in a photobioreactor exposed to a diel light/dark rhythm and using standard BG11 as the growth medium. We found that the strain that combined all three genetic modifications, i.e. xfpk overexpression in a double pta and ach deletion background, showed the highest levels of PHB production from all the strains tested here. Encouragingly, the production levels obtained: 232 mg L− 1, ~ 12% (w/w) of the dry biomass weight, and a productivity of 7.3 mg L− 1 d− 1; are to the best of our knowledge, the highest ever reported for PHB production directly from CO2

The genus Cannabis (Family Cannabaceae) is probably indigenous to wet habitats of Asiatic continent. The long coexistence between mankind and Cannabis led to an early domestication of the plant, which soon showed an amazing spectrum of possible utilizations, as a source of textile fibers, as well as narcotic and psychoactive compounds. Nowadays, the specie(s) belonging to the genus Cannabis are represented by myriads of cultivated varieties, often with unstable taxonomic foundations. The nomenclature of Cannabis has been the object of numerous nomenclatural treatments. Linnaeus in Species Plantarum (1753) described a single species of hemp, Cannabis sativa, whereas Lamarck (1785) proposed two species of Cannabis: C. sativa, the species largely cultivated in Western Continent, and Cannabis indica, a wild species growing in India and neighboring countries. The dilemma about the existence of the species C. indica considered distinct from C. sativa continues up to present days. Due to their prevalent economic interest, the nomenclatural treatment is particularly important as far as it concerns the cultivated varieties of Cannabis. In this context, we propose to avoid the distinction between sativa and indica, suggesting a bimodal approach: when a cultivar has been correctly established. It could be advisable to apply a nomenclature system based on the International Code of Nomenclature for Cultivated Plants (ICNCP): it is not necessary to use the species epithets, sativa or indica, and a combination of the genus name and a cultivar epithet in any language and bounded by single quotation marks define an exclusive name for each Cannabis cultivar. In contrast, Cannabis varieties named with vernacular names by medical patients and recreational users, and lacking an adequate description as required by ICNCP, should be named as Cannabis strain, followed by their popularized name and without single quotation marks, having in mind that their names have no taxonomical validity.

The increasing impact of plastic materials on the environment is a growing global concern. In regards to this circumstance, it is a major challenge to find new sources for the production of bioplastics. Poly-β-hydroxybutyrate (PHB) is characterized by interesting features that draw attention for research and commercial ventures. Indeed, PHB is eco-friendly, biodegradable, and biocompatible. Bacterial fermentation processes are a known route to produce PHB. However, the production of PHB through the chemoheterotrophic bacterial system is very expensive due to the high costs of the carbon source for the growth of the organism. On the contrary, the production of PHB through the photoautotrophic cyanobacterium system is considered an attractive alternative for a low-cost PHB production because of the inexpensive feedstock (CO₂ and light). This paper regards the evaluation of four independent strategies to improve the PHB production by cyanobacteria: (i) the design of the medium; (ii) the genetic engineering to improve the PHB accumulation; (iii) the development of robust models as a tool to identify the bottleneck(s) of the PHB production to maximize the production; and (iv) the continuous operation mode in a photobioreactor for PHB production. The synergic effect of these strategies could address the design of the optimal PHB production process by cyanobacteria. A further limitation for the commercial production of PHB via the biotechnological route are the high costs related to the recovery of PHB granules. Therefore, a further challenge is to select a low-cost and environmentally friendly process to recover PHB from cyanobacteria.