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
Project description:We report the application of single-molecule-based sequencing technology for high-throughput profiling of miRNAs in goat muscle tissue.We identified 1120 miRNAs in fetus and lamb muscle tissue; 895 were known miRNAs and 313 were novel miRNAs. According to analysis, 192 miRNAs were up-regulated in fetus samples compared to lamb samples, while 121 miRNAs were down-regulated.To confirmed stage-specific differences in the abundance of certain miRNAs, we focused on the most up-regulated miRNA and found to be predominantly expressed in lamb muscle tissue, suggesting a potential role in muscle development.It has become a molecular marker for breeding programs of mutton production.
Project description:Lactococcus piscium strain MKFS47 is a psychrotrophic spoilage lactic acid bacterium, isolated from the cold-stored modified atmosphere packaged broiler filet strips with the first signs of spoilage. For the experiment L. piscium MKFS47 was grown in MRS broth without acetate with 2% glucose, samples were taken at 3h, 5h and 11h in three replicates. The extracted RNA was sequenced using SOLiD 5500XL. RNA-seq reads were mapped against L. piscium MKFS47 genome and were counted per gene using Lifescope software. The experiment was conducted to identify the time-course differential expression of the L. piscium MKFS47 genes.
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.
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:meat spoilage bacteria Genome sequencing and assembly