The traditional order Mischococcales (Xanthophyceae) is polyphyletic with some original members now classified in a separate class, Eustigmatophyceae. However, most mischococcalean species have not yet been studied in detail, raising the possibility that many of them still remain misplaced. We established an algal culture (strain CCALA 838) determined as one such species, Trachydiscus minutus (Bourr.) H. Ettl, and studied the morphology, ultrastructure, life cycle, pigment composition, and phylogeny using the 18S rRNA gene. We discovered a zoosporic part of the life cycle of this alga. Zoospore production was induced by darkness, suppressed by light, and was temperature dependent. The zoospores possessed one flagellum covered with mastigonemes and exhibited a basal swelling, but a stigma was missing. Ultrastructural investigations of vegetative cells revealed plastids lacking both a connection to the nuclear envelope and a girdle lamella. Moreover, we described biogenesis of oil bodies on the ultrastructural level. Photosynthetic pigments of T. minutus included as the major carotenoids violaxanthin and vaucheriaxanthin (ester); we detected no chl c. An 18S rRNA gene-based phylogenetic analysis placed T. minutus in a clade with species of the genus Pseudostaurastrum and with Goniochloris sculpta Geitler, which form a sister branch to initially studied Eustigmatophyceae. In summary, our results are inconsistent with classifying T. minutus as a xanthophycean and indicate that it is a member of a novel deep lineage of the class Eustigmatophyceae.

Cyanobacteria and green algae are phototrophic microorganisms showing high diversity in their cellular structure in response to the environmental conditions of the niche where they occur. Production of exopolysaccharides (EPS) in response to adverse conditions is one of the important features of these organisms. EPS are present mainly around their cells/ filaments as an enveloped layer and released outside. EPS play protective functions and are important for their survival in stressed habitats exposed to radiation, desiccation and elevated temperatures. This review discusses the production, extraction and possible commercial applications of EPS produced by cyanobacteria and green algae.

Biochar (BC) was characterized as a new carbonaceous material for the adsorption of toluene from water. The tested BC was produced from pine wood gasification, and its sorption ability was compared with that of more common carbonaceous materials such as activated carbon (AC). Both materials were characterized in terms of textural features and sorption abilities by kinetic and equilibrium tests. AC and BC showed high toluene removal from water. Kinetic tests demonstrated that BC is characterized by faster toluene removal than AC is. Textural features demonstrated that the porosity of AC is double that of BC. Nevertheless, equilibrium tests demonstrated that the sorption ability of BC is comparable with that of AC, so the materials’ porosity is not the only parameter that drives toluene adsorption. The specific adsorption ability (mg sorbed m−2 of surface) of the BC is higher than that of AC: toluene is more highly sorbed onto the biochar surface. Biochar is furthermore obtained from biomaterial thermally treated for making energy; this also makes the use of BC economically and environmentally convenient compared with AC, which, as a manufactured material, must be obtained in selected conditions for this type of application.

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The inhibition and eradication of oral biofilms is increasingly focused on the use of plant extracts as mouthwashes and toothpastes adjuvants. Here, we report on the chemical composition and the antibiofilm activity of 15 methanolic extracts of Iris species against both mono-(Pseudomonas aeruginosa, Staphylococcus aureus) and multi-species oral biofilms (Streptococcus gordonii, Veillonella parvula, Fusobacterium nucleatum subsp. nucleatum, and Actinomyces naeslundii). The phytochemical profiles of Iris pallida s.l., Iris versicolor L., Iris lactea Pall., Iris carthaliniae Fomin, and Iris germanica were determined by ultra-high performance liquid chromatography-high-resolution tandem mass spectroscopy (UHPLC-HRMS/MS) analysis, and a total of 180 compounds were identified among Iris species with (iso)flavonoid dominancy. I. pallida, I. versicolor, and I. germanica inhibited both the quorum sensing and adhesion during biofilm formation in a concentration-dependent manner. However, the extracts were less active against maturated biofilms. Of the five tested species, Iris pallida s.l. was the most effective at both inhibiting biofilm formation and disrupting existing biofilms, and the leaf extract exhibited the strongest inhibitory effect compared to the root and rhizome extracts. The cytotoxicity of the extracts was excluded in human fibroblasts. The inhibition of bacterial adhesion significantly correlated with myristic acid content, and quorum sensing inhibition correlated with the 7-β-hydroxystigmast-4-en-3-one content. These findings could be useful for establishing an effective tool for the control of oral biofilms and thus dental diseases.

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