Biology subjects

Neu, T. R.

Publications and source records attributed to Neu, T. R..

4 recordsLinked to original sources

bioRxiv2023

Evolution of genotypic and phenotypic diversity in multispecies biofilms

Bacterial fitness and adaptability in microbial communities are influenced by interspecies interactions and spatial organization. This study investigated how these factors shape the evolutionary dynamics of Bacillus thuringiensis. A distinct phenotypic variant of B. thuringiensis emerged consistently under both planktonic and biofilm conditions, as well as in monospecies and mixed-species settings, but was strongly selected in biofilms and during coexistence with Pseudomonas defluvii and/ or Pseudomonas brenneri. Compared to its ancestor, the variant exhibited shorter generation times, reduced sporulation, auto-aggregation, and lower biomass in mixed-species biofilms. Mutations in the spo0A regulator, which controls sporulation and biofilm matrix production, were identified in all variants. Proteomics revealed a reduction in TasA, a key matrix protein, in the variant but increased levels in co-culture with P. brenneri. These findings highlight how interspecies interactions drive B. thuringiensis diversification, promoting traits like reduced matrix production and species coexistence, with implications for microbial consortia applications in agriculture and biopesticides.

microbiology↗

bioRxiv2023

Production of extracellular polymeric substances in granular sludge under selection for Accumulibacter and Competibacter

Granular sludge intensifies the removal of nutrients from wastewater. Granules structured by extracellular polymeric substances (EPS) can be recovered as biomaterial. Links between microbial selection and EPS formation during granulation need to get uncovered. We inoculated anaerobic-aerobic sequencing batch reactors with either flocs or granules to study the relationships between microbial selection, bioaggregation, exopolymer formation, and EPS composition. Selection for slow-growing organisms like the model polyphosphate- accumulating organism "Candidatus Accumulibacter" (max. 83% vs. amplicon sequencing read counts) and glycogen-accumulating organism "Ca. Competibacter" (max. 45%) sustained granulation. Gel-forming exopolymers were produced as high as above 40% of the volatile solids of the biomass by stepwise increase of the organic loading rate (0.3 to 2.0 g CODAc d-1 LR-1). Confocal laser scanning microscopy, FT-IR spectroscopy, and HPAE-PAD chromatography revealed the complex and dynamic chemical compositions of the structural EPS in relation to microbial population shifts along reactor regimes. The analysis of 20 representative genomes of "Ca. Accumulibacter" and "Ca. Competibacter" recovered from public databases revealed their functional potential to produce EPS among other representative wastewater microorganisms. The more than 40 functional gene categories annotated highlight the complexity of EPS metabolic networks from monomers processing to assembly, export, and epimerizations. The combination of ecological engineering principles and systems microbiology will help unravel and direct the production of EPS from wastewater, valorizing residual granular sludge into beneficial biomaterials for the circular economy. HighlightsO_LISelection for slow-growing organisms like PAOs and GAOs fostered a robust granulation. C_LIO_LIStructural EPS were produced above 40% of biomass volatile content under high loading. C_LIO_LIChemical composition of EPS evolved together with the microbial community composition. C_LIO_LIGenomic insights highlighted the genetic potential of PAOs and GAOs for EPS formation. C_LIO_LIMicrobial communities are complex; further are their EPS compositions and metabolisms. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=130 SRC="FIGDIR/small/534144v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@a163e2org.highwire.dtl.DTLVardef@1a4ab94org.highwire.dtl.DTLVardef@1fc93d4org.highwire.dtl.DTLVardef@14d4b7f_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2021

Unraveling the critical growth factors for stable cultivation of (nano-sized) Micrarchaeota

Micrarchaeota are members of the archaeal DPANN superphylum. These so far poorly characterized archaea have been found to have reduced genomes and likely depend on interactions with host organisms for growth and survival. Here we report on the enrichment of the first stable co-culture of a member of the Micrarchaeota together with its host, as well as the isolation of the latter. Electron microscopic analysis suggest that growth is dependent on the physical interaction of the two organisms within a biofilm. The interaction seems to be ensured by the necessity to grow in form of a biofilm. Furthermore, transcriptomic analyses indicate a shift towards biofilm formation of the host as a result of co-cultivation. Finally, genomic, metabolomic, extracellular polymeric substance (EPSs) and lipid content analyses reveal that the Micrarchaeon symbiont relies on the acquisition of metabolites from its host and thereby provide first insights into the basis of symbiont-host interactions.

microbiology↗

bioRxiv2020

Production of nonulosonic acids in the extracellular polymeric substances of Candidatus Accumulibacter phosphatis

Nonulosonic acids (NulOs) are a family of acidic carbohydrates with a nine-carbon backbone, which include different related structures, such as sialic acids. They have mainly been studied for their relevance in animal cells and pathogenic bacteria. Recently, sialic acids have been discovered as important compound in the extracellular matrix of virtually all microbial life and in "Candidatus Accumulibacter phosphatis", a well-studied polyphosphate-accumulating organism, in particular. Here, bioaggregates highly enriched with these bacteria (approx. 95% based on proteomic data) were used to study the production of NulOs in an enrichment of this microorganism. Fluorescence lectin-binding analysis, enzymatic quantification, and mass spectrometry were used to analyze the different NulOs present, showing a wide distribution and variety of these carbohydrates, such as sialic acids and bacterial NulOs, in the bioaggregates. Phylogenetic analysis confirmed the potential of "Ca. Accumulibacter" to produce different types of NulOs. Proteomic analysis showed the ability of "Ca. Accumulibacter" to reutilize and reincorporate these carbohydrates. This investigation points out the importance of diverse NulOs in non-pathogenic bacteria, which are normally overlooked. Sialic acids and other NulOs should be further investigated for their role in the ecology of "Ca. Accumulibacter" in particular, and biofilms in general. Key PointsO_LI"Ca. Accumulibacter" has the potential to produce a range of nonulosonic acids. C_LIO_LIMass spectrometry and lectin binding can reveal the presence and location of nonulosonic acids. C_LIO_LIRole of nonulosonic acid in non-pathogenic bacteria needs to be studied in detail. C_LI

microbiology↗