Background: Natural biological magnetite nanoparticles are widely distributed from microorganisms to humans. It is found to be very important in organisms, especially in navigation. Moreover, purified magnetite nanoparticles also have potential applications in bioengineering and biomedicine. Magnetotactic bacteria (MTB) is considered one of the most abundant species around the world which can form intracellular membrane enveloped magnetic nanoparticles, referred to as magnetosomes. To our knowledge, the biomineralization of magnetosome in MTB involves a serious of genes located on a large unstable genomic region named magnetosome island, which specially exists in MTB. The magnetite core of magnetosome formed via a Fe (III) ion intermediates, for instance, α -Fe ₂ O ₃ and ferrihydrite. Though the biosynthesis of magnetosome represents a general biomineralization mechanism of biogenic magnetite, knowledge of magnetosome biosynthesis and biomineralization remains very limited. Method: Cells used in this study were cultured in a 7.5-L bioreactor, samples for intermediate capture were taken each certain time interval after the generation of magnetosome biosynthesis condition. High-resolution transmission electron microscopy were used to analyze the detailed structure of magnetosomes. The parameters of the crystal structures were obtained by Fast Fourier Transform analyses. Results: In this study, we identified a novel intermediate phase, ε -Fe ₂ O ₃ , during the magnetite maturation process in MTB via kinetic analysis. Unlike α -Fe ₂ O ₃ , which has been reported as a precursor during magnetosome biosynthesis in MTB before, ε -Fe ₂ O ₃ , due to its thermal instability, is a rare phase with scarce natural abundance. This finding confirmed that ε -Fe ₂ O ₃ is an important novel intermediate during the biomineralization of magnetosome in MTB, and shed new light on the magnetosome biosynthesis pathway.

Myostatin (MSTN) regulates muscle development and body metabolism through a variety of pathways and is a core target gene for gene editing in livestock. Gut fungi constitute a small part of the gut microbiome and are important to host health and metabolism. The influence of MSTN mutations on bovine gut fungi remains unknown. In this study, Internal Transcribed Spacer (ITS) high-throughput sequencing was conducted to explore the composition of gut fungi in the MSTN mutant (MT) and wild-type (WT) cattle, and 5,861 operational taxonomic units (OTUs) were detected and classified into 16 phyla and 802 genera. The results of the alpha diversity analysis indicated that no notable divergence was displayed between the WT and MT cattle; however, significant differences were noticed in the composition of fungal communities. Eight phyla and 18 genera were detected. According to the prediction of fungal function, saprotroph fungi were significantly more abundant in the MT group. The correlation analysis between gut fungal and bacterial communities revealed that MSTN mutations directly changed the gut fungal composition and, at the same time, influenced some fungi and bacteria by indirectly regulating the interaction between microorganisms, which affected the host metabolism further. This study analyzed the role of MSTN mutations in regulating the host metabolism of intestinal fungi and provided a theoretical basis for the relationship between MSTN and gut fungi.

Introduction: MSTN is a well-studied inhibitor of skeletal muscle development, but its mechanism of affecting gut metabolites and the functions it exerts through this pathway are still unclear. This study aims to reveal how MSTN affects the metabolism process by regulating gut metabolites.Methods: Combined analysis of jejunal contents metabolome and jejunal tissue transcriptome was used to compare the differences in intestinal metabolites and intestinal tissue gene expression between MSTN mutant and wild-type bovines.Results: Metabolomic analysis identified that compared to wild-type bovine, the abundance of 304 metabolites were significantly changed in MSTN mutant cattle including 142 upregulated and 162 downregulated. Transcriptome results showed that the expression level of 1541 genes were influenced by MSTN disruption, including 536 upregulated genes and 1005 downregulated genes, which were categorized into 311 KEGG signaling pathways, primarily related to disease and metabolism. Correlation analysis results suggested a notable cross-regulation between the transcript levels of some specific genes in jejunal tissues and the abundance of jejunal metabolites, represented by fatty metabolites and genes associated with fatty acid degradation, synthesis and elongation.Discussion: Collectively, the result of this study indicated that MSTN gene mutation led to alterations in gut microbial metabolites by increasing the abundance of beneficial monounsaturated fatty acids (MUFAs) such as oleic acid, then to promote fatty acid degradation while inhibiting its synthesis by regulating the expression levels of relevant genes. These results provide a foundation for understanding the effects of MSTN gene mutations on gut metabolites and its certain functions that MSTN regulated via gut metabolites

Gallibacterium anatis is an emerging pathogen causing substantial economic losses in global poultry production. Despite its growing clinical significance, the genomic basis of pathogenicity and antimicrobial resistance in this species remains poorly understood, particularly in China. We sequenced and analyzed five clinical G. anatis isolates from Chinese layer chickens alongside 31 global strains, their genomes ranged from 2.25 to 2.81 Mb with 39.8% average GC content. Phylogenetic analysis revealed that Chinese isolates cluster according to historical breeding stock importation patterns, reflecting international trade influences on pathogen distribution. Contemporary isolates showed extensive multidrug resistance compared to the antimicrobial-sensitive historical strain F149, with resistance profiles correlating directly with documented antibiotic usage in Chinese poultry production. Virulence analysis identified universal conservation of the RTX toxin system (97–100% prevalence) across all strains, contrasting sharply with variable distribution of other factors including fimbriae (30–35%) and secretion systems (50–60%). All strains harbored CRISPR-Cas systems, predominantly types I and III, indicating strain-specific phage defense adaptations. The RTX toxin system represents a core virulence mechanism and potential universal vaccine target for G. anatis. The rapid evolution from antimicrobial-sensitive to extensively resistant phenotypes demonstrates how global poultry trade accelerates both pathogen spread and resistance development. These findings provide molecular insights for targeted interventions against an increasingly problematic poultry pathogen.

Deoxynivalenol (DON) is a mycotoxin commonly found in cereals. It has strong toxicity with high stability, thus it is easy to remain in food and cause serious poisoning symptoms to consumers. To establish an efficient and simple DON detection system, a biological nano magnetic particle called bacterial magnetosomes (BMs) extracted from magnetotactic bacteria with ultrasonic crushing and magnetic adsorption was used in this study. A single-stranded DNA aptamer specifically binding to DON was coupled to the surface of MBs by two different crosslinking agents, glutaraldehyde and polyethyleneimine (PEI), respectively, to synthesize two kinds of BMs-aptamer complexes for enriching DON. Then, the adsorption rate of the complex to DON was determined by HPLC. In the results, the absolute DON adsorption capacity of 1 mg BMs-aptamer complex was 27.24 ng when glutaraldehyde was used as crosslinker and 27.64 ng when PEI was used as crosslinker. The optimization results of desorption conditions showed that under the optimal elution conditions (DNase I+methanol for 2 times), the elution rate of DON adsorbed by BMs-glutaraldehyde-aptamer reached 72.7%, while the elution rate of DON adsorbed by BMs-PEI-aptamer complex reached 64.1%. Overall, the current study enriched the applications of magnetosomes in mycotoxin detection, and also provides new idea for the efficient enrichment and recovery of DON.