Biology subjects

Lood, R.

Publications and source records attributed to Lood, R..

3 recordsLinked to original sources

bioRxiv2026

Site, Fertilization and Season Structure the Soil Microbiome and its Interactions with Bdellovibrio and Like Organisms Predators

The contribution of predation between bacteria to microbial community dynamics in agricultural fields has hardly been investigated. Here. dynamics of general prokaryotes (GEP) and of the predators Bdellovibrionales (Bd) and Bacteriovoracales (Bac) (Bdellovibrio-and-Like Organisms, BALOs) were studied in two agricultural fields differing in organic and mineral input regimes, for one year. Season, but not fertilization, affected absolute sizes of GEP and of BALO communities. 16S rRNA gene community analysis identified numerous novel Bd and Bac lineages, with none of the dominant BALOs related to characterized isolates. A few dominant BALO amplicon sequence variants (ASVs) persisted year-round, whereas others showed seasonal- or treatment specific responses. GEP, Bd, and Bac ASV -diversity was mostly influenced by season, with some changes due to fertilization in Bd, and Bac communities. Seasonal changes, site, and fertilization regimes influenced {beta}-diversity of GEP, Bd and Bac communities and determined the structure of BALO-gram-negative bacteria interaction networks, signaling that niche segregation acts at the microbiome-BALO interface. Accordingly, we suggest that shifts in GEP community structure triggered by environmental changes and agricultural practices cascade to BALO predators, in turn affecting BALO-microbiome interactions. These dynamics may be harnessed to manipulate the soil microbiome to benefit sustainable environmental and agricultural outcomes. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=121 SRC="FIGDIR/small/735237v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@ee25dcorg.highwire.dtl.DTLVardef@f79940org.highwire.dtl.DTLVardef@16e48a2org.highwire.dtl.DTLVardef@1628c9e_HPS_FORMAT_FIGEXP M_FIG The soil microbiome and the microbial predators Bdellovibrio and Like Organisms (BALOs) are influenced by environmental parameters (season) and agricultural practice (fertilization) in their population dynamics, diversity and interactions. BALO diversity is high, and novel clades are found with BALOs differing in abundance and persistence. Microbiome-BALO interactions suggest environment and agricultural practice-dependence of niche segregation in BALOs. BALOs - and other micro-predators-may thus be integrated in the development of soil microbiome manipulations for environmental and agricultural applications. C_FIG

microbiology↗

bioRxiv2026

Mycoplasma immunoglobulin binding protein universally binds human antibodies, thereby reducing Fab arm flexibility and displacing antigens in immune complexes

Mycoplasma immunoglobulin binding (MIB) protein plays a key role in immune evasion across several Mycoplasma species. MIB tightly interacts with the Fab domain of immunoglobulin G, inducing conformational changes that disrupt the antigen-binding site. Here, we reveal that MIB binds strongly and universally to all major isotypes and subclasses of human antibodies and can thus serve as a bait protein to efficiently deplete antibodies from serum. Our results demonstrate strong interactions between MIB and a diverse set of both recombinant monoclonal and endogenous polyclonal antibodies, the latter purified from serum or colostrum. All antibodies, including IgG and IgA monomers, J-chain coupled IgA dimers, and IgM pentamers, consistently bind two copies of MIB per antibody protomer. Using cross-linking mass spectrometry, we pinpoint that antibody-MIB interactions involve conserved regions of the variable and constant antibody domains, independent of isotype. Furthermore, we demonstrate that MIB not only disrupts the Fab-antigen interaction but also restricts Fab flexibility, as visualized by atomic force microscopy. Conversely, MIB does not affect Fc-mediated protein interactions, as exemplified by the successful reconstitution of a 36-subunit immune complex, (IgG)6-(MIB)12-C1q.

biochemistry↗

bioRxiv2021

Streptococcus pyogenes forms serotype and local environment-dependent inter-species protein complexes

Streptococcus pyogenes is known to cause both mucosal and systemic infections in humans. In this study, we used a combination of quantitative and structural mass spectrometry techniques to determine the composition and structure of the interaction network formed between human plasma proteins and the surface of different S. pyogenes serotypes. Quantitative network analysis revealed that S. pyogenes form serotype-specific interaction networks that are highly dependent on the domain arrangement of the surface-attached M protein. Subsequent structural mass spectrometry analysis and computational modelling on one of the M proteins, M28 revealed that the network structure changes across different host microenvironments. We report that M28 binds secretory IgA via two separate binding sites with high affinity in saliva. During vascular leakage mimicked by increasing plasma concentrations in saliva, the binding of secretory IgA was replaced by binding of monomeric IgA and C4BP. This indicates that an upsurge of C4BP in the local microenvironment due to damage of the mucosal membrane drives binding of C4BP and monomeric IgA to M28. The results suggest that S. pyogenes has evolved to form microenvironment-dependent host-pathogen protein complexes to combat the human immune surveillance during both mucosal and systemic infections.

microbiology↗