Dataset Information

Pseudomonas koreensis Recovered From Raw Yak Milk Synthesizes a ?-Carboline Derivative With Antimicrobial Properties.

ABSTRACT: Natural evolution in microbes exposed to antibiotics causes inevitable selection of resistant mutants. This turns out to be a vicious cycle which requires the continuous discovery of new and effective antibiotics. For the last six decades, we have been relying on semisynthetic derivatives of natural products discovered in "Golden Era" from microbes, especially Streptomyces sp. Low success rates of rational drug-design sparked a resurgence in the invention of novel natural products or scaffolds from untapped or uncommon microbial niches. Therefore, in this study, we examined the microbial diversity inhabiting the yak milk for their ability to produce antimicrobial compounds. We prepared the crude fermentation extracts of fifty isolates from yak milk and screened them against indicator strains for the inhibitory activity. Later, with the aid of gel filtration chromatography followed by reversed-phase HPLC, we isolated one antimicrobial compound Y5-P1 from the strain Y5 (Pseudomonas koreensis) which showed bioactivity against Gram-positive and Gram-negative bacteria. The compound was chemically characterized using HRMS, FTIR, and NMR spectroscopy and identified as 1-acetyl-9H-?-carboline-3-carboxylic acid. It showed minimum inhibitory activity (MIC) in the range of 62.5-250 ?g /ml. The cytotoxicity results revealed that IC50 against two mammalian cell lines i.e., HepG2 and HEK293T was 500 and 750 ?g/ml, respectively. This is the first report on the production of this derivative of ?-carboline by the microorganism. Also, the study enlightens the importance of microbes residing in uncommon environments or unexplored habitats in the discovery of a diverse array of natural products which could be designed further as drug candidates against highly resistant pathogens.

SUBMITTER: Kaur M

PROVIDER: S-EPMC6681700 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

<i>Pseudomonas koreensis</i> Recovered From Raw Yak Milk Synthesizes a β-Carboline Derivative With Antimicrobial Properties.

Kaur Manpreet M Jangra Manoj M Singh Harjodh H Tambat Rushikesh R Singh Nittu N Jachak Sanjay M SM Mishra Sunita S Sharma Charu C Nandanwar Hemraj H Pinnaka Anil Kumar AK

Frontiers in microbiology 20190729

Natural evolution in microbes exposed to antibiotics causes inevitable selection of resistant mutants. This turns out to be a vicious cycle which requires the continuous discovery of new and effective antibiotics. For the last six decades, we have been relying on semisynthetic derivatives of natural products discovered in "Golden Era" from microbes, especially <i>Streptomyces</i> sp. Low success rates of rational drug-design sparked a resurgence in the invention of novel natural products or scaf ...[more]

PMID: 31417521

Similar Datasets

Project description:BackgroundIt has been estimated that at least 3% of the USA population consumes unpasteurized (raw) milk from animal sources, and the demand to legalize raw milk sales continues to increase. However, consumption of raw milk can cause foodborne illness and be a source of bacteria containing transferrable antimicrobial resistance genes (ARGs). To obtain a comprehensive understanding of the microbiome and antibiotic resistome in both raw and processed milk, we systematically analyzed 2034 retail milk samples including unpasteurized milk and pasteurized milk via vat pasteurization, high-temperature-short-time pasteurization, and ultra-pasteurization from the United States using complementary culture-based, 16S rRNA gene, and metagenomic sequencing techniques.ResultsRaw milk samples had the highest prevalence of viable bacteria which were measured as all aerobic bacteria, coliform, and Escherichia coli counts, and their microbiota was distinct from other types of milk. 16S rRNA gene sequencing revealed that Pseudomonadaceae dominated raw milk with limited levels of lactic acid bacteria. Among all milk samples, the microbiota remained stable with constant bacterial populations when stored at 4?°C. In contrast, storage at room temperature dramatically enriched the bacterial populations present in raw milk samples and, in parallel, significantly increased the richness and abundance of ARGs. Metagenomic sequencing indicated raw milk possessed dramatically more ARGs than pasteurized milk, and a conjugation assay documented the active transfer of blaCMY-2, one ceftazidime resistance gene present in raw milk-borne E. coli, across bacterial species. The room temperature-enriched resistome differed in raw milk from distinct geographic locations, a difference likely associated with regionally distinct milk microbiota.ConclusionDespite advertised "probiotic" effects, our results indicate that raw milk microbiota has minimal lactic acid bacteria. In addition, retail raw milk serves as a reservoir of ARGs, populations of which are readily amplified by spontaneous fermentation. There is an increased need to understand potential food safety risks from improper transportation and storage of raw milk with regard to ARGs. Video Abstract.

Project description:The control of bacterial growth during milk processing is crucial for the quality maintenance of commercial milk and milk products. During a period of cold storage prior to heat treatments, some psychrotrophic bacteria grow and produce extracellular heat-resistant lipases and proteases that cause product defects. The use of lytic bacteriophages (phages) that infect and kill bacteria could be a useful tool for suppressing bacterial growth during this cold storage phase. In this study, we isolated a Pseudomonas lactis strain and a phage from raw cow's milk. Quantitative characterization of the phage was used to elucidate whether this phage was active under low temperatures and neutral pH and whether it was inactivated during pasteurization. Phage titer determination was possible under conditions ranging from pH 4 to 9 and from 3°C to 25°C; the phage was inactivated under pasteurization conditions at 63°C for 30 min. Furthermore, we showed that this phage reduced viable bacterial cell counts in both skim and whole milk. The results of this study represent the potential uses of phages for controlling psychrotrophic bacterial growth in raw cow's milk during cold storage.IMPORTANCE Suppression of bacterial growth in raw milk under cold storage is crucial for the quality control of commercially supplied milk. The use of lytic phages as low-cost microbicides is an attractive prospect. Due to strict host specificities, phages must be isolated from the raw milk where the host bacteria are growing. We first isolated the P. lactis bacterial strain and then the phage infecting that strain. Partial phage genomic analysis showed that this is a newly isolated phage, different from any previously reported. This study reports a lytic phage for P. lactis, and we have presented evidence here that this phage reduced viable bacterial cell counts not only in rich medium but also in skim and whole milk. As a result, we have concluded that the phage reported in this study would be useful in milk processing.

Dataset Information

Pseudomonas koreensis Recovered From Raw Yak Milk Synthesizes a ?-Carboline Derivative With Antimicrobial Properties.

Publications

<i>Pseudomonas koreensis</i> Recovered From Raw Yak Milk Synthesizes a β-Carboline Derivative With Antimicrobial Properties.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets