Bacteria
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PROVIDER: PRJNA574489 | ENA |
REPOSITORIES: ENA
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Project description:Oxygen and carbon dioxide are common protective gases used in modified atmosphere packaging (MAP) of meat. Within the package, they selectively suppress members of the spoilage microbiome, reshaping it to adapted species concomitantly growing upon MAP. Thus, this species must exhibit adaptation mechanisms to withstand the inhibitory effect of carbon dioxide and oxygen, and cope with selective nutrition on MAP meat. In order to uncover these mechanisms, the typical representative meat-spoiling bacteria Brochothrix (B.) thermosphacta TMW2.2101 and four lactic acid bacteria (LAB) Carnobacterium (C.) divergens TMW2.1577, C. maltaromaticum TMW2.1581, Leuconostoc (L.) gelidum subsp. gelidum TMW2.1618 and L. gelidum subsp. gasicomitatum TMW2.1619 were grown in a meat simulation medium under a controlled, sterile environment, aerated constantly with either air, 100%_N2, 30%_CO2/70%_O2 or 30%_CO2/70%_N2. Growth dynamics were monitored and a label-free quantitative mass spectrometric approach was employed to determine changes within the bacterial proteomes in response to the different gas atmospheres. Revealed bacterial tolerance to modified atmospheres (MA) comprise two possible scenarios: Either bacteria were intrinsically adapted to MA, exhibiting no proteomic regulation of enzymes (L. gelidum subsp. gelidum and gasicomitatum) or, tolerance was provided by varying specific metabolic adaptation (B. thermosphacta, C. divergens, C. maltaromaticum). In detail, metabolic adaptation mechanisms to oxygen comprised an enhanced oxidative stress reduction response, adjustment of the pyruvate metabolism and catabolic oxygen consuming reactions. Adaptation to carbon dioxide was characterized by an upregulation of proteins involved in intracellular pH homeostasis, maintenance of osmotic balance and alteration of the fatty acid composition of the cell membrane. We furthermore predict species-specific strategies for different and preferential carbon source utilization enabling a non-competitive coexistence on meat and resulting in a synergistic spoilage. We conclude that a gas atmosphere containing 30%_CO2/70%_O2 has no inhibitory effect on the analyzed prominent meat-spoiling bacteria whereas 30%_CO2/70%_N2 predictively inhibits C. divergens TMW21577 and B. thermosphacta TMW2.2101 but not the other three species. This gives a mechanistically explanation of their acknowledged status as typical spoilage organisms on packaged meats.
2020-02-05 | PXD016382 | Pride
Project description:A prototype oligonucleotide microarray was designed to detect and identify viable bacterial species with the potential to grow of common beer spoilage microorganisms from the genera Lactobacillus, Megasphaera, Pediococcus and Pectinatus. Probes targeted the intergenic spacer regions (ISR) between 16S and 23S rRNA, which were amplified in a combination of reverse transcriptase (RT) and polymerase chain reaction (PCR) prior to hybridization. This method allows the detection and discrimination of single bacterial species in a complex sample. Furthermore, microarrays using oligonucleotide probes targeting the ISR allow the distinction between viable bacteria with the potential to grow and non-growing bacteria. The results demonstrate the feasibility of oligonucleotide microarrays as a contamination control in food industry for the detection and identification of spoilage microorganisms within mixed population. Keywords: microarray, oligonucleotide, species-specific, detection, beer spoilage bacteria
2007-05-23 | GSE7840 | GEO
Project description:Aiming to reduce food spoilage, the present study developed novel highly active food-grade preservatives affecting a wide range of bacteria. For this purpose, storage proteins were extracted from food plants. After enzymatic hydrolysis by the digestive protease chymotrypsin, the peptide profiles were analyzed by ultrahigh-performance micro-liquid chromatography–triple quadrupole time-of-flight tandem mass spectrometry. Virtual screening identified 21 potential antimicrobial peptides in chickpea legumin. Among those, the peptides Leg1 (RIKTVTSFDLPALRFLKL) and Leg2 (RIKTVTSFDLPALRWLKL) exhibited antimicrobial activity against 16 different bacteria, including pathogens, spoilage-causing bacteria and two antibiotic-resistant strains. Minimum inhibitory concentrations (MIC) down to 15.6 µM indicated 10–1,000-fold higher activity of the novel antimicrobial peptides compared to conventional food preservatives. Moreover, Leg1 and Leg2 showed bactericidal activity in bacterial suspension and during the storage of raw pork meat.
2021-01-11 | PXD019257 | Pride
Project description:Pathogens and Spoilage isolates Genome sequencing
| PRJNA376487 | ENA
Project description:Six bacterial genomes, Geobacter metallireducens GS-15, Chromohalobacter salexigens, Vibrio breoganii 1C-10, Bacillus cereus ATCC 10987, Campylobacter jejuni subsp. jejuni 81-176 and Campylobacter jejuni NCTC 11168, all of which had previously been sequenced using other platforms were re-sequenced using single-molecule, real-time (SMRT) sequencing specifically to analyze their methylomes. In every case a number of new N6-methyladenine (m6A) and N4-methylcytosine (m4C) methylation patterns were discovered and the DNA methyltransferases (MTases) responsible for those methylation patterns were assigned. In 15 cases it was possible to match MTase genes with MTase recognition sequences without further sub-cloning. Two Type I restriction systems required sub-cloning to differentiate their recognition sequences, while four MTases genes that were not expressed in the native organism were sub-cloned to test for viability and recognition sequences. No attempt was made to detect 5-methylcytosine (m5C) recognition motifs from the SMRT sequencing data because this modification produces weaker signals using current methods. However, all predicted m6A and m4C MTases were detected unambiguously. This study shows that the addition of SMRT sequencing to traditional sequencing approaches gives a wealth of useful functional information about a genome showing not only which MTase genes are active, but also revealing their recognition sequences. Examination of the methylomes of six different strains of bacteria using kinetic data from single-molecule, real-time (SMRT) sequencing on the PacBio RS.
2012-10-04 | E-GEOD-40133 | biostudies-arrayexpress
Project description:Purpose: We investigate the evolutionary footprints of a bacteria-plasmid association consisting of Escherichia coli K-12 MG1655 and plasmid RP4 undergoing a long-term sub-MIC antibiotic stress. Methods: Bacterial mRNA profiles of evolved RP4-carrying strains (E:H:p) and ancestral RP4-carrying strains (A:H:p) were generated by deep sequencing on an Illumina Hiseq platform. The sequence reads that passed quality filters were analyzed by Burrows–Wheeler Aligner (BWA), followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. qRT–PCR validation was performed using TaqMan and SYBR Green assays Results: Using an optimized data analysis workflow, we mapped about 15 million sequence reads of E:H:p and 12 million sequence reads of A:H:p to the E. coli MG1655 genome (GCF_000801205.1) and differential expressed genes were identified with TopHat workflow. RNA-seq data showed that approximately 15% of the transcripts showed differential expression between the E:H:p and A:H:p strains, with a fold change ≥1 and p value <0.005. Altered expression of 26 genes was confirmed with qRT–PCR, demonstrating the high degree of sensitivity of the RNA-seq method. Data analysis with bowtie and TopHat workflows provided complementary insights in transcriptome profiling. Conclusions: Our study showed the coevolved bacteria-plasmid pairs has colonization traits superior to the wild-type parent strain. Antibiotic stress was necessary for bacterial evolution and evolved strains mostly employed transcriptional modifications to reduce plasmid-related cost in evolutionary adaptations. Several genes related to chromosome-encoded efflux pumps were transcriptionally upregulated, while most plasmid-harboring genes were downregulated based on RNA gene sequencing. These transcriptional modifications endowed evolved strains with resistant phenotype modifications, including the enhanced bacterial growth and biofilm formation.
2020-09-24 | GSE158461 | GEO
Project description:Mostly, lactic acid bacteria (LAB), including food-spoilage-associated, grow in communities consisting of several microbial species. The interspecies interactions eventually shape the structure and global activity of a given microbial community. Generally, the knowledge on system level responses of LAB (especially food-spoilage-associated) during such interactions is very limited. To study transcriptome responses during interactions between three MAP meat-spoilage-associated LAB (Leuconostoc gelidum subsp. gasicomitatum LMG 18811T, Lactococcus piscium MKFS47 and Lactobacillus oligofermentans LMG 22743T) we grew them separately in individual cultures and in mixed cultures pairwise (three combinations) and all together (triple culture) in three replicates on a glucose-containing growth medium (MRS) under microaerobic conditions at 25 C, samples were taken at three time points (3, 5 and 11 h) and extracted RNA were sequenced. The experiments were performed in two batches. At first (batch 1), co-cultivation of Le. gelidum and Lc. piscium accompanied with their individual cultures was performed and processed. The raw RNA-seq data for the individual culture of Lc. piscium from the batch 1 were uploaded earlier and are available in the ArrayExpress database under accession number E-MTAB-3245. Later (batch 2), two other pairwise cultures (Le. gelidum + Lb. oligofermentans and Lc. piscium + Lb. oligofermentans) and the triple culture were grown together with the individual cultures of all three LAB. Designations used for the sample names: G: Le. gelidum; P: Lc. piscium; O: Lb. oligofermentans; GO, PO, PG: pairwise cultures of the corresponding species; OPG: triple culture; b1: batch 1; b2: batch 2. Example: 3G2_b1: 3 h, Le. gelidum, 2nd replicate, batch 1; 11PO3_b2: 11 h, pairwise culture of Lc. piscium and Lb. oligofermentans, 3d replicate, batch 2. One sample (5PO3_b2) had very low number of reads ~ 9000, and, therefore, was not uploaded under this project. RNA extraction and library construction were done analogously as in the study (Andreevskaya M et al., 2015. Appl. Environ. Microbiol. 81:38003811, doi: 10.1128/AEM.00320-15). Ribosomal RNA was omitted. Libraries were sequenced in five lanes using SOLiD 5500XL (Life technologies, Foster City, Ca, USA) to produce 75 bp single-end reads. For the data submission, xsq files obtained from SOLiD 5500XL machine, were converted into fastq files. Adapter sequences were removed using cutadapt 1.4.1.
2018-04-27 | E-MTAB-5499 | biostudies-arrayexpress