Biology subjects

Asare, P. T.

Publications and source records attributed to Asare, P. T..

3 recordsLinked to original sources

bioRxiv2026

A putative GtrB-like glycosyltransferase modulates cation-dependent BCP8-2 phage infection and cell surface structure in Bacillus cereus

Bacillus cereus is a foodborne pathogen of growing concern due to its persistence and antimicrobial resistance. To identify host determinants influencing susceptibility to phage BCP8-2, a mini-Tn10 transposon mutant library of B. cereus ATCC 14579 was constructed and screened for altered phage susceptibility. A mutant (BC2012) showing partial resistance carried an insertion in BC_RS27090 (previously BC_5432), encoding a putative GtrB-like bactoprenol glycosyltransferase. Complementation restored phage sensitivity, confirming its functional involvement. Adsorption and efficiency-of-plating assays revealed significantly reduced phage binding and infectivity in the mutant, particularly under cation-rich conditions. Microscopy showed altered surface morphology with thinner, smoother cell walls. These data indicate that gtrB affects surface properties essential for cation-dependent phage adsorption and infection and provide a foundation for future studies on the role of surface glycosylation and ionic interactions in Gram-positive phage biology. ImportancePathogenic Bacillus cereus is resilient across diverse environments and produces diverse toxins linked to foodborne outbreaks. Bacteriophages provide an effective strategy to control B. cereus; however, molecular targets of phage-host interaction are poorly understood, limiting the effective phage-based control. Current study addresses this gap by identifying a putative bactoprenol glycosyltransferase (GtrB), a vital factor in phage BCP8-2 susceptibility. Data obtained highlights partial reduction of phage infection in the gtrB mutant, demonstrating that precise glycosylation is essential for effective phage binding and entry. Our findings provide significant insights for advancing phage therapy, antibiotic resistance, and B. cereus biocontrol in food and clinical settings.

microbiology↗

bioRxiv2025

Evaluating long-term stool preservation methods for maximizing the recovery of viable human fecal microbiota

The gut microbiome plays a fundamental role in human health, prompting efforts to catalogue and preserve its diversity across human populations. While DNA sequencing dominates microbiome research, cultivation remains essential for mechanistic studies and therapeutic development. Yet, best practices for long-term stool preservation remain limited. Here, we compared the stability of eight cryopreservation treatments for maintaining viable stool microbiota over a 1-year storage period at -80{degrees}C (freezer) or at -196{degrees}C (liquid nitrogen), using samples from infants, children, and adults. Combining cultivation on six media with 16S rRNA sequencing, we show that ultralow temperature cryopreservation has minimal impact on microbiota diversity compared to fresh cultures. Standard glycerol preservation and simple snap-freezing performed comparably to more complex and costly protocols, with all cultured samples retaining donor-specific microbiota profiles also after long-term cryopreservation. The lack of strong treatment-specific effects on microbiota composition suggest a shared microbial response to freeze-thaw stress favoring fast-growing taxa. Our findings offer practical, low-cost strategies for stool biobanking. ImportanceThe cultivation of bacterial taxa from complex communities, such as those in fecal samples, is essential for mechanistic studies and the development of microbiota-based therapeutics, including defined consortia and individual probiotic strains. Such cultivation efforts typically rely on previously stored samples; however, systematic knowledge regarding long-term preservation strategies that ensure viability and regrowth of constituent bacterial taxa remains limited. In this study, we systematically evaluated 16 distinct cryopreservation conditions to assess their efficacy in maintaining bacterial viability. Our results show that conventional glycerol-based preservation and simple snap-freezing are comparable in performance to more elaborate and cost-intensive protocols. Moreover, we identified the duration of sample transport prior to freezing as a critical determinant of post-thaw bacterial recovery. These findings provide valuable data on the relative effectiveness of various preservation methods and support the use of low-cost, easily implementable strategies that are particularly suitable for application in resource-limited settings.

microbiology↗

bioRxiv2019

Isolation and comparative genomic analysis of reuterin-producing Lactobacillus reuteri from poultry gastrointestinal tract

Lactobacillus reuteri is a natural inhabitant of selected animal and human gastrointestinal tract (GIT). Certain strains have the capacity to transform glycerol to 3-hydroxypropionaldehyde (3-HPA), further excreted to form reuterin, a potent antimicrobial system. Reuterin-producing strains may be applied as a natural antimicrobial in feed to prevent pathogen colonization of animals, such as in poultry, and replace added antimicrobials. To date, only seven L. reuteri strains isolated from poultry have been characterized which limits phylogenetic studies and host-microbes interactions characterization. This study aimed to isolate L. reuteri strains from poultry GIT and to characterize their reuterin production and antimicrobial resistance (AMR) profiles using phenotypic and genetic methods. Seventy reuterin-producing strains were isolated from poultry crop, faeces and caeca and twenty-five selected for further characterization. Draft genomes were generated for the new 25 isolates and integrated in a phylogenetic tree of 40 strains from different hosts. Phylogenetic analysis based on gene content as well as on core genomes showed grouping of the selected 25 L. reuteri poultry isolates within the poultry/human lineage VI. Strains harbouring pdu-cob-cbi-hem genes (23/25) produced between 156 mM {+/-} 11 and 330 mM {+/-} 14 3-HPA, from 600 mM of glycerol, in the conditions of the test. All 25 poultry strains were sensitive to cefotaxime (MIC between 0.016 and 1 g/mL) and penicillin (MIC between 0.02 and 4 g/mL). Akin to the reference strains DSM20016 and SD2112, the novel isolates were resistant to penicillin, possibly associated with identified point mutations in ponA, pbpX, pbpF and pbpB. All strains resistant to erythromycin (4/27) carried the ermB gene, and it was only present in poultry strains. All strains resistant to tetracycline (5/27) harbored tetW gene. This study confirms the evolutionary history of poultry/human lineage VI and identifies pdu-cob-cbi-hem as a frequent trait but not always present in this lineage. L. reuteri poultry strains producing high 3-HPA yield may have potential to prevent enteropathogen colonization of poultry.

genomics↗