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Microalgae exhibit extensive potential for counteracting imminent challenges in the nutraceutical, pharmaceutical, and biomaterial sectors, but lack economic viability. Biotechnological systems for contamination control could advance the economic viability of microalgal feedstock, but the selection of suitable strains that sustainably promote microalgal productivity remains challenging. In this study, total diversity in phototrophic Chlorella vulgaris cultures was assessed by amplicon sequencing comparing cultures subjected to five different cultivation conditions. Overall, 12 eukaryotic and 53 prokaryotic taxa were identified; Alphaproteobacteria (36.7%) dominated the prokaryotic and C. vulgaris (97.2%) the eukaryotic community. Despite altering cultivation conditions, 2 eukaryotic and 40 prokaryotic taxa remained stably associated with C. vulgaris; diversity between systems did not significantly differ (P > 0.05). Among those, 20 cultivable taxa were isolated and identified by 16S rDNA sequencing. Subsequently, controlled co-cultures were investigated showing stable associations of C. vulgaris with Sphingopyxis sp. and Pseudomonas sp.. Out-competition of C. vulgaris due to ammonium or phosphate limitation was not observed, despite significantly elevated growth of Sphingopyxis sp. and Tistrella sp.. (P < 0.05). Nevertheless, C. vulgaris growth was impaired by Tistrella sp.. Hence, the study provides a selection of stable indigenous prokaryotes and eukaryotes for artificially tailoring microbial biocenoses. Following a bottom-up approach, it provides a base for controlled co-cultures and thus the establishment of even more complex biocenoses using interkingdom assemblages. Such assemblages can benefit from functional richness for improved nutrient utilization, as well as bacterial load control, which can enhance microalgal feedstock production through improved culture stability and productivity., (© 2020 The Authors. Journal of Phycology published by Wiley Periodicals LLC on behalf of Phycological Society of America.)

Background: There has been a dramatic increase in investigations on the potential mechanistic role of the intestinal microbiota in various diseases and factors modulating intestinal microbial composition. We recently reported on intestinal microbial shifts after smoking cessation in humans. In this study, we aimed to conduct further microbial analyses and verify our previous results obtained by pyrosequencing using a direct quantitative microbial approach., Methods: Stool samples of healthy smoking human subjects undergoing controlled smoking cessation during a 9-week observational period were analyzed and compared with 2 control groups, ongoing smoking and nonsmoking subjects. Fluorescence in situ hybridization was applied to quantify specific bacterial groups., Results: Intestinal microbiota composition was substantially altered after smoking cessation as characterized by an increase in key representatives from the phyla of Firmicutes (Clostridium coccoides, Eubacterium rectale, and Clostridium leptum subgroup) and Actinobacteria (HGC bacteria and Bifidobacteria) as well as a decrease in Bacteroidetes (Prevotella spp. and Bacteroides spp.) and Proteobacteria (β- and γ-subgroup of Proteobacteria)., Conclusions: As determined by fluorescence in situ hybridization, an independent direct quantitative microbial approach, we could confirm that intestinal microbiota composition in humans is influenced by smoking. The characteristics of observed microbial shifts suggest a potential mechanistic association to alterations in body weight subsequent to smoking cessation. More importantly, regarding previously described microbial hallmarks of dysbiosis in inflammatory bowel diseases, a variety of observed microbial alterations after smoking cessation deserve further consideration in view of the divergent effect of smoking on the clinical course of Crohn's disease and ulcerative colitis.

Background: Clostridium difficile infections upon antibiotic disruption of the gut microbiota are potentially lethal. Fecal microbiota transplantation (FMT) is a promising treatment option for recurrent C. difficile-associated disease (CDAD). Here, we present a patient with recurrent CDAD that received FMT, leading to full recovery for what has now been 3 years. We performed metagenomic sequencing on stool samples to assess if there are indications for recolonization with C. difficile and changes in the gut microbiota after FMT., Methods: DNA from the stool of the donor and recipient was subjected to illumina sequencing. Obtained read sets were assembled to contiguous sequences and open reading frames were predicted. Deduced proteins were taxonomically assigned., Results: We detected complex and apparently healthy microbiomes in the donor's and recipient's intestines after FMT, but no indications for C. difficile colonization., Conclusions: Metagenomic analysis proved suitable to analyze the intestinal microbiome after FMT. Discussion of our evaluation procedure and data management may be helpful for future studies. We demonstrated restoration of a healthy and diverse gut microbiome with chimeric composition from donor and recipient, and long-lasting clearance of C. difficile. The procedure is simple, cheap, caused no side effects, and was stable over 3 years.