Talukder, H. | Search bioRxiv

bioRxiv2020

In-vivo evaluation of the anti-diarrheal effect of Lactococcus lactis subspecies lactis and Lactococcus piscium isolated from yogurt.

Lactobacillus and Lactococcus species found in the yogurt of different sources are most widely assayed and used all over the world as a probiotic agent. This study aimed to isolate and identify novel probiotic agents with therapeutic value against diarrhea. Initially, the probiotic properties of the isolated lactic acid bacteria from the yogurt samples of the Chittagong division, Bangladesh, were evaluated. All probiotic candidates inhibited the growth of selected pathogens, including Escheriachia coli, Serratia sp. Salmonella paratyphi, Streptococcus Group-B, Staphylococcus aureus, Haemophillus influenzae, Bacillus subtillis, and Klebsiella pneumoniae. Lactococcus lactis subsp lactis were found most useful in inhibiting all the selected pathogens. When the probiotics were applied against castor oil-induced diarrhea in the rat model, Lactococcus lactis subspecies lactis and Lactococcus piscium were found significantly effective relative to the controls indicating their potentiality as an alternative therapeutic against diarrhea. HighlightsO_LILactococcus lactis subspecies lactis and Lactococcus piscium has shown potentiality to be a therapeutic agent against castor-oil induced diarrhea in an animal model. C_LIO_LILactococcus lactis subspecies lactis and Lactococcus piscium inhibited the growth of specified pathogens. C_LI

microbiology↗

bioRxiv2017

Longitudinal differential abundance analysis of microbial marker-gene surveys using smoothing splines

BackgroundHigh-throughput targeted sequencing of the 16S ribosomal RNA marker gene is often used to profile and characterize the taxonomic composition of microbial communities. This type of big high-through sequencing data is rapidly being applied to various infectious diseases like diarrhea. While many studies are limited to single \"snapshots\" of these communities, there is increasing recognition that longitudinal profiling of these communities are required to understand community dynamics and the complex relationships between dynamics and phenotypes of interest. Statistical methods that determine microbial features that are differentially expressed are required as an initial step to characterizing phenotypic associations with community dynamics in big data and infectious diseases.\n\nResultsWe present a novel method for longitudinal marker-gene surveys based on smoothing splines that allows discovery and inference of time periods where specific microbial features are differentially abundant. We applied our method to three 16S marker-gene surveys, including, groups of gnotobiotic mice on two diets, patients challenged with ETEC (H10407), and a vaginal microbiome of healthy women. Employing our methodology we recover known bacterial differences and highlight a few extra species providing insight into when specific changes occurred. Additionally, in the cohort challenged with ETEC we recover proposed probiotic bacteria Bacteroides xylanisolvens, Collinsella aerofaciens, and Faecalibacterium prausnitzii associatons with healthy individuals.\n\nConclusionsThe method presented is, to our knowledge, the first flexible method of its kind implemented as a software capable of detecting time periods of differential abundance for microbial features species between two or more sample groups of interest. Our method is available within the metagenomeSeq open-source software for analysis of metagenomic package available through the Bioconductor project and is termed metaSplines.

genomics↗