scholarly journals Transcriptome analysis of Listeria monocytogenes exposed to beef fat reveals antimicrobial and pathogenicity attenuation mechanisms

2021 ◽  
Author(s):  
Yuan Yao Chen ◽  
Arun Kommadath ◽  
Payam Vahmani ◽  
Jeyachchandran Visvalingam ◽  
Michael E. R. Dugan ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Function Analysis ◽  
Bacterial Pathogen ◽  
Monounsaturated Fatty Acids ◽  
Transcriptional Analysis ◽  
Natural Antimicrobials ◽  
Expression Of Genes ◽  
Virulence Attenuation

Listeria monocytogenes is a deadly intracellular pathogen mostly associated with consumption of ready-to-eat foods. This study investigated the effectiveness of total beef fat (BF-T) from flaxseed fed cattle, and its fractions enriched with monounsaturated fatty acids (BF-MUFA) and polyunsaturated fatty acids (BF-PUFA) along with commercially available long chain fatty acids (LC-FA) as natural antimicrobials against L. monocytogenes. BF-T was ineffective at concentrations up to 6 mg/ml, while L. monocytogenes was susceptible to BF-MUFA and BF-PUFA with the minimum inhibitory concentrations (MICs) at pH 7 being 0.33 ± 0.21 mg/ml and 0.06 ± 0.03 mg/ml, respectively. The MIC of C14:0 was significantly lower than those of C16:0 and C18:0 (P < 0.05). c9-C16:1, C18:2n-6 and C18:3n-3, showed stronger inhibitory activity than c9-C18:1 and conjugated C18:2, with MICs < 1 mg/ml. Furthermore, global transcriptional analysis by RNA-seq was performed to characterize the response of L. monocytogenes to selected FA. Function analysis indicated that antimicrobial LC-UFA repressed the expression of genes associated with nutrient transmembrane transport, energy generation, and oxidative stress resistance. On the other hand, upregulation of ribosome assembly and translation process is possibly associated with adaptive and repair mechanisms in response to LC-UFA. Virulence genes and genes involved in bile, acid and osmotic stress were largely downregulated, more so for c9-C16:1, C18:2n-6 and C18:3n-3, likely through interaction the master virulence regulator PrfA and the alternative Sigma factor σB. Importance Listeria monocytogenes is a bacterial pathogen known for its ability to survive and thrive under adverse environments and as such its control poses a significant challenge, especially with the trend of minimally processed and ready-to-eat foods. This work investigated the effectiveness of fatty acids from various sources as natural antimicrobials against L. monocytogenes, and evaluated their potential role in L. monocytogenes pathogenicity modulation, using the strain ATCC 19111. The findings show LC-UFA including unsaturated beef fat fractions from flaxseed fed cattle could have the potential to be used as effective antimicrobials for L. monocytogenes, through controlling growth as well as virulence attenuation. This not only advances our understanding on the mode of action of LC-UFA against L. monocytogenes, but also suggests the potential use of beef fat or its fractions as natural antimicrobials for controlling foodborne pathogens.

Investigation of the roles of AgrA and σB regulators in Listeria monocytogenes adaptation to roots and soil

2020 ◽  
Vol 367 (3) ◽  
Author(s):  
Catarina M Marinho ◽  
Dominique Garmyn ◽  
Laurent Gal ◽  
Maja Z Brunhede ◽  
Conor O'Byrne ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Parental Strain ◽  
Festuca Arundinacea ◽  
Double Mutant ◽  
Response Regulator ◽  
Cell Communication ◽  
Bacterial Pathogen ◽  
Transcriptional Analysis ◽  
Root Colonisation ◽  
Two Systems

ABSTRACT Little is known about the regulatory mechanisms that ensure the survival of the food-borne bacterial pathogen Listeria monocytogenes in the telluric environment and on roots. Earlier studies have suggested a regulatory overlap between the Agr cell–cell communication system and the general stress response regulator σB. Here, we investigated the contribution of these two systems to root colonisation and survival in sterilised and biotic soil. The ability to colonise the roots of the grass Festuca arundinacea was significantly compromised in the double mutant (∆agrA∆sigB). In sterile soil at 25°C, a significant defect was observed in the double mutant, suggesting some synergy between these systems. However, growth was observed and similar population dynamics were shown in the parental strain, ΔagrA and ΔsigB mutants. In biotic soil at 25°C, viability of the parental strain declined steadily over a two-week period highlighting the challenging nature of live soil environments. Inactivation of the two systems further decreased survival. The synergistic effect of Agr and σB was stronger in biotic soil. Transcriptional analysis confirmed the expected effects of the mutations on known Agr- and σB-dependent genes. Data highlight the important role that these global regulatory systems play in the natural ecology of this pathogen.

scholarly journals The Inhibitory Effect of Plant Extracts on Growth of the Foodborne Pathogen, Listeria monocytogenes

Antibiotics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 319 ◽  
Author(s):  
Marina Ceruso ◽  
Jason A. Clement ◽  
Matthew J. Todd ◽  
Fangyuan Zhang ◽  
Zuyi Huang ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Plant Extracts ◽  
Foodborne Pathogens ◽  
Food Industry ◽  
Foodborne Pathogen ◽  
The United States ◽  
Inhibitory Effect ◽  
Microscopic Level ◽  
Natural Antimicrobials ◽  
Minimal Inhibitory Concentrations

Listeria monocytogenes is a foodborne pathogen responsible for about 1600 illnesses each year in the United States (US) and about 2500 confirmed invasive human cases in European Union (EU) countries. Several technologies and antimicrobials are applied to control the presence of L. monocytogenes in food. Among these, the use of natural antimicrobials is preferred by consumers. This is due to their ability to inhibit the growth of foodborne pathogens but not prompt negative safety concerns. Among natural antimicrobials, plant extracts are used to inactivate L. monocytogenes. However, there is a large amount of these types of extracts, and their active compounds remain unexplored. The aim of this study was to evaluate the antibacterial activity against L. monocytogenes of about 800 plant extracts derived from plants native to different countries worldwide. The minimal inhibitory concentrations (MICs) were determined, and scanning electron microscopy (SEM) was used to verify how the plant extracts affected L. monocytogenes at the microscopic level. Results showed that 12 of the plant extracts had inhibitory activity against L. monocytogenes. Future applications of this study could include the use of these plant extracts as new preservatives to reduce the risk of growth of pathogens and contamination in the food industry from L. monocytogenes.

scholarly journals Compartmentalization of the Broad-Range Phospholipase C Activity to the Spreading Vacuole Is Critical for Listeria monocytogenes Virulence

2006 ◽  
Vol 75 (1) ◽  
pp. 44-51 ◽  
Author(s):  
P. S. Marie Yeung ◽  
Yoojin Na ◽  
Amanda J. Kreuder ◽  
Hélène Marquis
Keyword(s):  
Listeria Monocytogenes ◽  
Phospholipase C ◽  
Membrane Damage ◽  
Bacterial Pathogen ◽  
Host Cells ◽  
Virulence Attenuation ◽  
Infected Cells ◽  
Host Cell Membranes ◽  
Cell Spread

ABSTRACT Listeria monocytogenes is a bacterial pathogen that multiplies in the cytosol of host cells and spreads directly from cell to cell by using an actin-based mechanism of motility. The broad-range phospholipase C (PC-PLC) of L. monocytogenes contributes to bacterial escape from vacuoles formed upon cell-to-cell spread. PC-PLC is made as an inactive proenzyme whose activation requires cleavage of an N-terminal propeptide. During infection, PC-PLC is activated specifically in acidified vacuoles. To assess the importance of compartmentalizing PC-PLC activity during infection, we created a mutant that makes constitutively active PC-PLC (the plcBΔpro mutant). Results from intracellular growth and cell-to-cell spread assays showed that the plcBΔpro mutant was sensitive to gentamicin, suggesting that unregulated PC-PLC activity causes damage to host cell membranes. This was confirmed by the observation of a twofold increase in staining of live infected cells by a non-membrane-permeant DNA fluorescent dye. However, membrane damage was not sufficient to cause cell lysis and was dependent on bacterial cell-to-cell spread, suggesting that damage was localized to bacterium-containing filopodia. Using an in vivo competitive infection assay, we observed that the plcBΔpro mutant was outcompeted up to 200-fold by the wild-type strain in BALB/c mice. Virulence attenuation was greater when mice were infected orally than when they were infected intravenously, presumably because the plcBΔpro mutant was initially outcompeted in the intestines, reducing the number of mutant bacteria reaching the liver and spleen. Together, these results emphasize the importance for L. monocytogenes virulence of compartmentalizing the activity of PC-PLC during infection.

scholarly journals Persistence and Transfer of Foodborne Pathogens to Sunflower and Pea Shoot Microgreens during Production in Soil-Free Cultivation Matrix

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 446
Author(s):  
Wenjun Deng ◽  
Gina M. Misra ◽  
Christopher A. Baker ◽  
Kristen E. Gibson
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Salmonella Enterica ◽  
Bacterial Pathogen ◽  
Controlled Environment ◽  
Pathogen Persistence ◽  
Sprouted Seeds

Microgreens are an emerging salad crop with properties similar to those of sprouted seeds and lettuce. This study aimed to determine bacterial pathogen persistence during microgreen cultivation and transfer from soil-free cultivation matrix (SFCM) to mature microgreens. Salmonella enterica subsp. enterica ser. Javiana and Listeria monocytogenes were inoculated onto biostrate mats as well as peat SFCM and sampled (day 0). Next, sunflower and pea shoot seeds were planted (day 0) and grown in a controlled environment until the microgreen harvest (day 10). On day 10, SFCM and microgreens were sampled to determine the pathogen levels in the SFCM and the pathogen transfer to microgreens during production. Salmonella Javiana log CFU/g were significantly higher than L. monocytogenes in SFCM on day 10 in both planted and unplanted regions (p < 0.05). Significant differences in pathogen transfer (log CFU/g) were observed between the pea shoot and sunflower microgreens, regardless of the pathogen or SFCM type (p < 0.05). Meanwhile, pathogen transfer to the pea shoot and sunflower microgreens from the biostrate was 1.53 (95% CI: −0.75–3.81) and 5.29 (95% CI: 3.01–7.57) mean log CFU/g, respectively, and transfer from the peat was 0.00 (95% CI: −2.28–2.28) and 2.64 (95% CI: 0.36–4.92) mean log CFU/g, respectively. Results demonstrate that pathogen transfer to microgreens during production is influenced by SFCM and microgreen variety.

scholarly journals Endothelin-1 Overexpression Improves Renal Function in eNOS Knockout Mice

2015 ◽  
Vol 37 (4) ◽  
pp. 1474-1490 ◽  
Author(s):  
Oleg Tsuprykov ◽  
Lyubov Chaykovska ◽  
Axel Kretschmer ◽  
Johannes-Peter Stasch ◽  
Thiemo Pfab ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Fatty Acids ◽  
Interstitial Fibrosis ◽  
Tissue Remodeling ◽  
Monounsaturated Fatty Acids ◽  
Plasma Metabolites ◽  
Protein Excretion ◽  
Filtration Barrier ◽  
Expression Of Genes ◽  
The Status

Background/Aims: To investigate the renal phenotype under conditions of an activated renal ET-1 system in the status of nitric oxide deficiency, we compared kidney function and morphology in wild-type, ET-1 transgenic (ET+/+), endothelial nitric oxide synthase knockout (eNOS-/-) and ET+/+eNOS-/- mice. Methods: We assessed blood pressure, parameters of renal morphology, plasma cystatin C, urinary protein excretion, expression of genes associated with glomerular filtration barrier and tissue remodeling, and plasma metabolites using metabolomics. Results: eNOS-/- and ET+/+eNOS-/- mice developed hypertension. Osteopontin, albumin and protein excretion were increased in eNOS-/- and restored in ET+/+eNOS-/- animals. All genetically modified mice developed renal interstitial fibrosis and glomerulosclerosis. Genes involved in tissue remodeling (serpine1, TIMP1, Col1a1, CCL2) were up-regulated in eNOS-/-, but not in ET+/+eNOS-/- mice. Plasma levels of free carnitine and acylcarnitines, amino acids, diacyl phosphatidylcholines, lysophosphatidylcholines and hexoses were descreased in eNOS-/- and were in the normal range in ET+/+eNOS-/- mice. Conclusion: eNOS-/- mice developed renal dysfunction, which was partially rescued by ET-1 overexpression in eNOS-/- mice. The metabolomics results suggest that ET-1 overexpression on top of eNOS knockout is associated with a functional recovery of mitochondria (rescue effect in β-oxidation of fatty acids) and an increase in antioxidative properties (normalization of monounsaturated fatty acids levels).

Potentiation of effects of weight loss by monounsaturated fatty acids in obese NIDDM patients

Diabetes ◽  
1996 ◽  
Vol 45 (5) ◽  
pp. 569-575 ◽  
Author(s):  
C. C. Low ◽  
E. B. Grossman ◽  
B. Gumbiner
Keyword(s):  
Fatty Acids ◽  
Weight Loss ◽  
Monounsaturated Fatty Acids ◽  
Niddm Patients

Differential Effects of Dietary Fatty Acids on Body Composition and Adiposity

2020 ◽  
Vol 16 (2) ◽  
pp. 142-154 ◽  
Author(s):  
Hadi Emamat ◽  
Zahra Yari ◽  
Hossein Farhadnejad ◽  
Parvin Mirmiran
Keyword(s):  
Fatty Acids ◽  
Body Composition ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Total Body Weight ◽  
Fat Distribution ◽  
Monounsaturated Fatty Acids ◽  
Dietary Fatty Acids ◽  
Dietary Fats ◽  
Total Body

Recent evidence has highlighted that fat accumulation, particularly abdominal fat distribution, is strongly associated with metabolic disturbance. It is also well-recognized that the metabolic responses to variations in macronutrients intake can affect body composition. Previous studies suggest that the quality of dietary fats can be considered as the main determinant of body-fat deposition, fat distribution, and body composition without altering the total body weight; however, the effects of dietary fats on body composition have controversial results. There is substantial evidence to suggest that saturated fatty acids are more obesogen than unsaturated fatty acids, and with the exception of some isomers like conjugate linoleic acid, most dietary trans fatty acids are adiposity enhancers, but there is no consensus on it yet. On the other hand, there is little evidence to indicate that higher intake of the n-3 and the n-6 polyunsaturated fatty acids can be beneficial in attenuating adiposity, and the effect of monounsaturated fatty acids on body composition is contradictory. Accordingly, the content of this review summarizes the current body of knowledge on the potential effects of the different types of dietary fatty acids on body composition and adiposity. It also refers to the putative mechanisms underlying this association and reflects on the controversy of this topic.

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