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Piro F, Masci S, Kannan G, Focaia R, Schultz TL, Thaprawat P, Carruthers VB, Di Cristina M. A Toxoplasma gondii putative amino acid transporter localizes to the plant-like vacuolar compartment and controls parasite extracellular survival and stage differentiation. mSphere 2024; 9:e0059723. [PMID: 38051073 PMCID: PMC10871165 DOI: 10.1128/msphere.00597-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 12/07/2023] Open
Abstract
Toxoplasma gondii is a protozoan parasite that infects a broad spectrum of hosts and can colonize many organs and cell types. The ability to reside within a wide range of different niches requires substantial adaptability to diverse microenvironments. Very little is known about how this parasite senses various milieus and adapts its metabolism to survive, replicate during the acute stage, and then differentiate to the chronic stage. T. gondii possesses a lysosome-like organelle known as the plant-like vacuolar compartment (PLVAC), which serves various functions, including digestion, ion storage and homeostasis, endocytosis, and autophagy. Lysosomes are critical for maintaining cellular health and function by degrading waste materials and recycling components. To supply the cell with the essential building blocks and energy sources required for the maintenance of its functions and structures, the digested solutes generated within the lysosome are transported into the cytosol by proteins embedded in the lysosomal membrane. Currently, a limited number of PLVAC transporters have been characterized, with TgCRT being the sole potential transporter of amino acids and small peptides identified thus far. To bridge this knowledge gap, we used lysosomal amino acid transporters from other organisms as queries to search the T. gondii proteome. This led to the identification of four potential amino acid transporters, which we have designated as TgAAT1-4. Assessing their expression and sub-cellular localization, we found that one of them, TgAAT1, localized to the PLVAC and is necessary for normal parasite extracellular survival and bradyzoite differentiation. Moreover, we present preliminary data showing the possible involvement of TgAAT1 in the PLVAC transport of arginine.IMPORTANCEToxoplasma gondii is a highly successful parasite infecting a broad range of warm-blooded organisms, including about one-third of all humans. Although Toxoplasma infections rarely result in symptomatic disease in individuals with a healthy immune system, the incredibly high number of persons infected, along with the risk of severe infection in immunocompromised patients and the potential link of chronic infection to mental disorders, makes this infection a significant public health concern. As a result, there is a pressing need for new treatment approaches that are both effective and well tolerated. The limitations in understanding how Toxoplasma gondii manages its metabolism to adapt to changing environments and triggers its transformation into bradyzoites have hindered the discovery of vulnerabilities in its metabolic pathways or nutrient acquisition mechanisms to identify new therapeutic targets. In this work, we have shown that the lysosome-like organelle plant-like vacuolar compartment (PLVAC), acting through the putative arginine transporter TgAAT1, plays a pivotal role in regulating the parasite's extracellular survival and differentiation into bradyzoites.
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Affiliation(s)
- Federica Piro
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Silvia Masci
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Geetha Kannan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Riccardo Focaia
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Tracey L. Schultz
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Pariyamon Thaprawat
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Vern B. Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Manlio Di Cristina
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
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Piro F, Masci S, Kannan G, Focaia R, Schultz TL, Carruthers VB, Di Cristina M. A Toxoplasma gondii putative arginine transporter localizes to the plant-like vacuolar compartment and controls parasite extracellular survival and stage differentiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.31.555807. [PMID: 37693549 PMCID: PMC10491228 DOI: 10.1101/2023.08.31.555807] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Toxoplasma gondii is a protozoan parasite that infects a broad spectrum of hosts and can colonize many organs and cell types. The ability to reside within a wide range of different niches requires substantial adaptability to diverse microenvironments. Very little is known about how this parasite senses various milieus and adapts its metabolism to survive, replicate during the acute stage, and then differentiate to the chronic stage. Most eukaryotes, from yeast to mammals, rely on a nutrient sensing machinery involving the TORC complex as master regulator of cell growth and cell cycle progression. The lysosome functions as a signaling hub where TORC complex assembles and is activated by transceptors, which both sense and transport amino acids, including the arginine transceptor SLC38A9. While most of the TORC components are lost in T. gondii , indicating the evolution of a distinct nutrient sensing mechanism, the parasite's lysosomal plant-like vacuolar compartment (PLVAC) may still serve as a sensory platform for controlling parasite growth and differentiation. Using SLC38A9 to query the T. gondii proteome, we identified four putative amino acid transporters, termed TgAAT1-4, that structurally resemble the SLC38A9 arginine transceptor. Assessing their expression and sub-cellular localization, we found that one of them, TgAAT1, localized to the PLVAC and is necessary for normal parasite extracellular survival and bradyzoite differentiation. Moreover, we show that TgAAT1 is involved in the PLVAC efflux of arginine, an amino acid playing a key role in T. gondii differentiation, further supporting the hypothesis that TgAAT1 might play a role in nutrient sensing. IMPORTANCE T. gondii is a highly successful parasite infecting a broad range of warm-blood organisms including about one third of all humans. Although Toxoplasma infections rarely result in symptomatic disease in individuals with a healthy immune system, the incredibly high number of persons infected along with the risk of severe infection in immunocompromised patients and the potential link of chronic infection to mental disorders make this infection a significant public health concern. As a result, there is a pressing need for new treatment approaches that are both effective and well-tolerated. The limitations in understanding how Toxoplasma gondii manages its metabolism to adapt to changing environments and triggers its transformation into bradyzoites have hindered the discovery of vulnerabilities in its metabolic pathways or nutrient acquisition mechanisms to identify new therapeutic targets. In this work, we have shown that the lysosome-like organelle PLVAC, acting through the putative arginine transporter TgAAT1, plays a pivotal role in regulating the parasite's extracellular survival and differentiation into bradyzoites.
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Nakano M. An improved DNA extraction method for detecting Bacillus subtilis spores in spiked foods and beverages. Int J Food Microbiol 2023; 401:110280. [PMID: 37327536 DOI: 10.1016/j.ijfoodmicro.2023.110280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 05/24/2023] [Accepted: 06/03/2023] [Indexed: 06/18/2023]
Abstract
Bacillus and Paenibacillus spp. are essential aerobic spoilage bacteria in various food industry sectors. Spoilage from microorganisms occurs at many points throughout food production systems. Due to their complex wall structures, spores can resist heat, radiation, chemical agents, and enzymatic treatments. An alkaline lysis and mechanical disruption combination method was developed and evaluated to counter this. This combination method effectively improved DNA extraction from B. subtilis spore cells spiked into food (solid) and beverages (liquid milk and coffee) at concentrations down to 102 CFU/mL or g when spiked into food matrices and drinks. Released DNA recoveries were 27 % and 25 % for potato salad and 38 % and 36 % for whole corn spiked at 106 and 103 CFU/mL concentrations. Conversely, there was a low recovery for wheat flour (10 % and 8.8 %) and milk powders (12 % and 25 %) at 106 and 103 CFU/mL spiked concentrations. The combination method provides rapid, specific, reliable, and accurate signature sequences identification for the detection and presence confirmation of psychrophilic and psychrotolerant spoilage spore cells, improving food spoilage assessments and food control applications.
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Affiliation(s)
- Miyo Nakano
- Division of Food Science, Toyo Institute of Food Technology, 23-2, 4-chome, Minami-hanayashiki, Kawanishi, Hyogo 666-0026, Japan.
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McVey C, Gordon U, Haughey SA, Elliott CT. Assessment of the Analytical Performance of Three Near-Infrared Spectroscopy Instruments (Benchtop, Handheld and Portable) through the Investigation of Coriander Seed Authenticity. Foods 2021; 10:956. [PMID: 33925477 PMCID: PMC8145574 DOI: 10.3390/foods10050956] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/14/2021] [Accepted: 04/23/2021] [Indexed: 11/16/2022] Open
Abstract
The performance of three near-infrared spectroscopy (NIRS) instruments was compared through the investigation of coriander seed authenticity. The Thermo Fisher iS50 NIRS benchtop instrument, the portable Ocean Insights Flame-NIR and the Consumer Physics handheld SCiO device were assessed in conjunction with chemometric modelling in order to determine their predictive capabilities and use as quantitative tools through regression analysis. Two hundred authentic coriander seed samples and ninety adulterated samples were analysed on each device. Prediction models were developed and validated using SIMCA 15 chemometric software. All instruments correctly predicted 100% of the adulterated samples. The best models resulted in correct predictions of 100%, 98.5% and 95.6% for authentic coriander samples using spectra from the iS50, Flame-NIR and SCiO, respectively. The development of regression models highlighted the limitations of the Flame-NIR and SCiO for quantitative analysis, compared to the iS50. However, the results indicate their use as screening tools for on-site analysis of food, at various stages of the food supply chain.
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Affiliation(s)
| | | | - Simon A. Haughey
- ASSET Technology Centre, Institute for Global Food Security, School of Biological Sciences, Queen’s University Belfast, 19 Chlorine Gardens, Belfast BT9 5DL, Northern Ireland, UK; (C.M.); (U.G.); (C.T.E.)
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Evaluation of a Highly Efficient DNA Extraction Method for Bacillus anthracis Endospores. Microorganisms 2020; 8:microorganisms8050763. [PMID: 32443768 PMCID: PMC7285266 DOI: 10.3390/microorganisms8050763] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 11/19/2022] Open
Abstract
A variety of methods have been established in order to optimize the accessibility of DNA originating from Bacillusanthracis cells and endospores to facilitate highly sensitive molecular diagnostics. However, most endospore lysis techniques have not been evaluated in respect to their quantitative proficiencies. Here, we started by systematically assessing the efficiencies of 20 DNA extraction kits for vegetative B.anthracis cells. Of these, the Epicentre MasterPure kit gave the best DNA yields and quality suitable for further genomic analysis. Yet, none of the kits tested were able to extract reasonable quantities of DNA from cores of the endospores. Thus, we developed a mechanical endospore lysis protocol, facilitating the extraction of high-quality DNA. Transmission electron microscopy or the labelling of spores with the indicator dye propidium monoazide was utilized to assess lysis efficiency. Finally, the yield and quality of genomic spore DNA were quantified by PCR and they were found to be dependent on lysis matrix composition, instrumental parameters, and the method used for subsequent DNA purification. Our final standardized lysis and DNA extraction protocol allows for the quantitative detection of low levels (<50 CFU/mL) of B. anthracis endospores and it is suitable for direct quantification, even under resource-limited field conditions, where culturing is not an option.
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Yoshino H, Hori T, Hosomi M, Terada A. Identifying prokaryotes and eukaryotes disintegrated by a high-pressure jet device for excess activated sludge reduction. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107495] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Le Gratiet T, Poezevara T, Rouxel S, Houard E, Mazuet C, Chemaly M, Le Maréchal C. Development of An Innovative and Quick Method for the Isolation of Clostridium botulinum Strains Involved in Avian Botulism Outbreaks. Toxins (Basel) 2020; 12:E42. [PMID: 31936866 PMCID: PMC7020472 DOI: 10.3390/toxins12010042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/03/2020] [Accepted: 01/09/2020] [Indexed: 01/17/2023] Open
Abstract
Avian botulism is a serious neuroparalytic disease mainly caused by a type C/D botulinum neurotoxin produced by Clostridium botulinum group III, one of the entwined bacterial species from the Clostridiumnovyisensulato genospecies. Its isolation is very challenging due to the absence of selective media and the instability of the phage carrying the gene encoding for the neurotoxin. The present study describes the development of an original method for isolating C. botulinum group III strains. Briefly, this method consists of streaking the InstaGene matrix extraction pellet on Egg Yolk Agar plates and then collecting the colonies with lipase and lecithinase activities. Using this approach, it was possible to isolate 21 C. novyi sensu lato strains from 22 enrichment broths of avian livers, including 14 toxic strains. This method was successfully used to re-isolate type C, D, C/D, and D/C strains from liver samples spiked with five spores per gram. This method is cheap, user-friendly, and reliable. It can be used to quickly isolate toxic strains involved in avian botulism with a 64% success rate and C. novyi sensu lato with a 95% rate. This opens up new perspectives for C. botulinum genomic research, which will shed light on the epidemiology of avian botulism.
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Affiliation(s)
- Thibault Le Gratiet
- Unit of Hygiene and Quality of Poultry and Pork Products, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440 Ploufragan, France; (T.L.G.)
- UFR of Life Sciences and Environment, University of Rennes 1, 35 000 Rennes, France
| | - Typhaine Poezevara
- Unit of Hygiene and Quality of Poultry and Pork Products, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440 Ploufragan, France; (T.L.G.)
| | - Sandra Rouxel
- Unit of Hygiene and Quality of Poultry and Pork Products, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440 Ploufragan, France; (T.L.G.)
| | - Emmanuelle Houard
- Unit of Hygiene and Quality of Poultry and Pork Products, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440 Ploufragan, France; (T.L.G.)
| | - Christelle Mazuet
- National Reference Center for Anaerobic Bacteria and Botulism, Institut Pasteur, 25-28 rue du Docteur Roux, 75724 Paris, France
| | - Marianne Chemaly
- Unit of Hygiene and Quality of Poultry and Pork Products, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440 Ploufragan, France; (T.L.G.)
| | - Caroline Le Maréchal
- Unit of Hygiene and Quality of Poultry and Pork Products, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440 Ploufragan, France; (T.L.G.)
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Brauge T, Midelet-Bourdin G, Soumet C. Viability Detection of Foodborne Bacterial Pathogens in Food Environment by PMA-qPCR and by Microscopic Observation. Methods Mol Biol 2019; 1918:117-128. [PMID: 30580403 DOI: 10.1007/978-1-4939-9000-9_9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Foodborne pathogens are responsible of foodborne diseases and food poisoning and thus pose a great threat to food safety. These microorganisms can adhere to surface and form a biofilm composed of an extracellular matrix. This extracellular matrix protects bacterial cells from industrial environmental stress factors such as cleaning and disinfection operations. Moreover, during these environmental stresses, many bacterial species can enter a viable but nonculturable (VBNC) state. VBNC cells are characterized by a loss of cultivability on conventional bacteriological agar. This leads to an underestimation of total viable cells in environmental samples, and thus poses a risk for public health. In this chapter, we present a method to detect viable population of foodborne pathogens in industrial environmental samples using a molecular method with a combination of propidium monoazide (PMA) and quantitative PCR (qPCR) and a fluorescence microscopic method associated with the LIVE/DEAD BacLight™ viability stain.
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Affiliation(s)
- Thomas Brauge
- Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health and Safety, Boulogne sur Mer, France.,RMT Chlean, Joint Technological Network: Hygienic Design of Production Lines and Equipment, Fougères, France
| | - Graziella Midelet-Bourdin
- Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health and Safety, Boulogne sur Mer, France.,RMT Chlean, Joint Technological Network: Hygienic Design of Production Lines and Equipment, Fougères, France
| | - Christophe Soumet
- RMT Chlean, Joint Technological Network: Hygienic Design of Production Lines and Equipment, Fougères, France. .,Fougères Laboratory, ANSES, Fougères, France.
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