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Fesser A, Beilstein S, Kaiser M, Schmidt RS, Mäser P. Trypanosoma cruzi STIB980: A TcI Strain for Drug Discovery and Reverse Genetics. Pathogens 2023; 12:1217. [PMID: 37887733 PMCID: PMC10610277 DOI: 10.3390/pathogens12101217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/25/2023] [Accepted: 10/03/2023] [Indexed: 10/28/2023] Open
Abstract
Since the first published genome sequence of Trypanosoma cruzi in 2005, there have been tremendous technological advances in genomics, reverse genetics, and assay development for this elusive pathogen. However, there is still an unmet need for new and better drugs to treat Chagas disease. Here, we introduce a T. cruzi assay strain that is useful for drug research and basic studies of host-pathogen interactions. T. cruzi STIB980 is a strain of discrete typing unit TcI that grows well in culture as axenic epimastigotes or intracellular amastigotes. We evaluated the optimal parameters for genetic transfection and constructed derivatives of T. cruzi STIB980 that express reporter genes for fluorescence- or bioluminescence-based drug efficacy testing, as well as a Cas9-expressing line for CRISPR/Cas9-mediated gene editing. The genome of T. cruzi STIB980 was sequenced by combining short-read Illumina with long-read Oxford Nanopore technologies. The latter served as the primary assembly and the former to correct mistakes. This resulted in a high-quality nuclear haplotype assembly of 28 Mb in 400 contigs, containing 10,043 open-reading frames with a median length of 1077 bp. We believe that T. cruzi STIB980 is a useful addition to the antichagasic toolbox and propose that it can serve as a DTU TcI reference strain for drug efficacy testing.
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Affiliation(s)
- Anna Fesser
- Swiss Tropical and Public Health Institute, Department Medical Parasitology and Infection Biology, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
| | - Sabina Beilstein
- Swiss Tropical and Public Health Institute, Department Medical Parasitology and Infection Biology, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, Department Medical Parasitology and Infection Biology, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
| | - Remo S Schmidt
- Swiss Tropical and Public Health Institute, Department Medical Parasitology and Infection Biology, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Department Medical Parasitology and Infection Biology, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
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2
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Rao SPS, Gould MK, Noeske J, Saldivia M, Jumani RS, Ng PS, René O, Chen YL, Kaiser M, Ritchie R, Francisco AF, Johnson N, Patra D, Cheung H, Deniston C, Schenk AD, Cortopassi WA, Schmidt RS, Wiedemar N, Thomas B, Palkar R, Ghafar NA, Manoharan V, Luu C, Gable JE, Wan KF, Myburgh E, Mottram JC, Barnes W, Walker J, Wartchow C, Aziz N, Osborne C, Wagner J, Sarko C, Kelly JM, Manjunatha UH, Mäser P, Jiricek J, Lakshminarayana SB, Barrett MP, Diagana TT. Cyanotriazoles are selective topoisomerase II poisons that rapidly cure trypanosome infections. Science 2023; 380:1349-1356. [PMID: 37384702 DOI: 10.1126/science.adh0614] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/24/2023] [Indexed: 07/01/2023]
Abstract
Millions who live in Latin America and sub-Saharan Africa are at risk of trypanosomatid infections, which cause Chagas disease and human African trypanosomiasis (HAT). Improved HAT treatments are available, but Chagas disease therapies rely on two nitroheterocycles, which suffer from lengthy drug regimens and safety concerns that cause frequent treatment discontinuation. We performed phenotypic screening against trypanosomes and identified a class of cyanotriazoles (CTs) with potent trypanocidal activity both in vitro and in mouse models of Chagas disease and HAT. Cryo-electron microscopy approaches confirmed that CT compounds acted through selective, irreversible inhibition of trypanosomal topoisomerase II by stabilizing double-stranded DNA:enzyme cleavage complexes. These findings suggest a potential approach toward successful therapeutics for the treatment of Chagas disease.
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Affiliation(s)
- Srinivasa P S Rao
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
- Novartis Institute for Tropical Diseases, Singapore
| | - Matthew K Gould
- College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Jonas Noeske
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Manuel Saldivia
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Rajiv S Jumani
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Pearly S Ng
- Novartis Institute for Tropical Diseases, Singapore
| | - Olivier René
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Yen-Liang Chen
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
- Novartis Institute for Tropical Diseases, Singapore
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Ryan Ritchie
- College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | | | - Nila Johnson
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
| | - Debjani Patra
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Harry Cheung
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Colin Deniston
- Novartis Institutes for BioMedical Research, San Diego, CA, USA
| | | | | | - Remo S Schmidt
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Natalie Wiedemar
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Bryanna Thomas
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Rima Palkar
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
| | | | | | - Catherine Luu
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Jonathan E Gable
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Kah Fei Wan
- Novartis Institute for Tropical Diseases, Singapore
| | - Elmarie Myburgh
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Jeremy C Mottram
- York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | - Whitney Barnes
- Novartis Institutes for BioMedical Research, San Diego, CA, USA
| | - John Walker
- Novartis Institutes for BioMedical Research, San Diego, CA, USA
| | - Charles Wartchow
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Natasha Aziz
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Colin Osborne
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - Juergen Wagner
- Novartis Institute for Tropical Diseases, Singapore
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Christopher Sarko
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
| | - John M Kelly
- London School of Hygiene and Tropical Medicine, London, UK
| | - Ujjini H Manjunatha
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
- Novartis Institute for Tropical Diseases, Singapore
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Jan Jiricek
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institute for Tropical Diseases, Singapore
| | - Suresh B Lakshminarayana
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
- Novartis Institute for Tropical Diseases, Singapore
| | - Michael P Barrett
- College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Thierry T Diagana
- Novartis Institute for Tropical Diseases, Emeryville, CA, USA
- Novartis Institutes for BioMedical Research, Emeryville, CA, USA
- Novartis Institute for Tropical Diseases, Singapore
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3
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Bettera L, Dreier M, Schmidt RS, Gatti M, Berthoud H, Bachmann HP. Selective enrichment of the raw milk microbiota in cheese production: Concept of a natural adjunct milk culture. Front Microbiol 2023; 14:1154508. [PMID: 37180227 PMCID: PMC10169670 DOI: 10.3389/fmicb.2023.1154508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 03/30/2023] [Indexed: 05/16/2023] Open
Abstract
In cheese production, microorganisms are usually added at the beginning of the process as primary starters to drive curd acidification, while secondary microorganisms, with other pro-technological features important for cheese ripening, are added as selected cultures. This research aimed to investigate the possibilities of influencing and selecting the raw milk microbiota using artisanal traditional methods, providing a simple method to produce a natural supplementary culture. We investigated the production of an enriched raw milk whey culture (eRWC), a natural adjunct microbial culture produced from mixing an enriched raw milk (eRM) with a natural whey culture (NWC). The raw milk was enriched by spontaneous fermentation for 21 d at 10°C. Three milk enrichment protocols were tested: heat treatment before incubation, heat treatment plus salt addition, and no treatment. The eRMs were then co-fermented with NWC (ratio of 1:10) at 38°C for 6 h (young eRWC) and 22 h (old eRWC). Microbial diversity during cultures' preparation was evaluated through the determination of colony forming units on selective growth media, and next-generation sequencing (16S rRNA gene amplicon sequencing). The enrichment step increased the streptococci and lactobacilli but reduced microbial richness and diversity of the eRMs. Although the lactic acid bacteria viable count was not significantly different between the eRWCs, they harbored higher microbial richness and diversity than NWC. Natural adjunct cultures were then tested in cheese making trials, following the microbial development, and assessing the chemical quality of the 120 d ripened cheeses. The use of eRWCs slowed the curd acidification in the first hours of cheese making but the pH 24 h after production settled to equal values for all the cheeses. Although the use of diverse eRWCs contributed to having a richer and more diverse microbiota in the early stages of cheese making, their effect decreased over time during ripening, showing an inferior effect to the raw milk microbiota. Even if more research is needed, the optimization of such a tool could be an alternative to the practice of isolating, geno-pheno-typing, and formulating mixed-defined-strain adjunct cultures that require knowledge and facilities not always available for artisanal cheese makers.
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Affiliation(s)
- Luca Bettera
- Department of Food and Drug, University of Parma, Parma, Italy
- Agroscope, Bern, Switzerland
| | | | | | - Monica Gatti
- Department of Food and Drug, University of Parma, Parma, Italy
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Wenger A, Bär C, Portmann R, Schmidt RS, Eugster E, Weisskopf L, Irmler S. The aminotransferase Aat initiates 3-phenyllactic acid biosynthesis in Pediococcus acidilactici. Front Microbiol 2023; 14:1150425. [PMID: 37187531 PMCID: PMC10175570 DOI: 10.3389/fmicb.2023.1150425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/14/2023] [Indexed: 05/17/2023] Open
Abstract
The function of the aminotransferase Aat (GenBank Protein WP_159211138) from Pediococcus acidilactici FAM 18098 was studied in vivo. For this purpose, the gene was replaced with an erythromycin resistance gene using the temperature-sensitive Escherichia coli-Pediococcus shuttle plasmid pSET4T_Δaat. The knockout was verified by PCR and genome sequencing. Subsequently, the differences between the metabolism of the knockout and of the wild-type strain were investigated by determining the free amino acids and organic acids in culture supernatants. It was found that the knockout mutant no longer synthesized 3-phenyllactic acid (PLA) and 4-hydroxyphenyllactic acid (HPLA). Additionally, the mutant strain no longer catabolized phenylalanine. Metabolic pathway analysis using the KEGG database indicate that P. acidilactici cannot synthesize α-ketoglutarate that is a predominant amino-group acceptor in many transamination reactions. To study the transfer of the amino group of phenylalanine, the wild-type strain was incubated with [15N] phenylalanine. Mass spectrometry showed that during fermentation, [15N] alanine was formed, indicating that pyruvic acid is an amino group acceptor in P. acidilactici. The present study shows that Aat plays a crucial role in PLA/HPLA biosynthesis and pyruvic acid is an amino acceptor in transamination reactions in P. acidilactici.
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Affiliation(s)
- Alexander Wenger
- Agroscope, Bern, Switzerland
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | | | | | | | - Elisabeth Eugster
- School of Agricultural, Forest and Food Sciences HAFL, Bern University of Applied Sciences, Zollikofen, Switzerland
| | - Laure Weisskopf
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Stefan Irmler
- Agroscope, Bern, Switzerland
- *Correspondence: Stefan Irmler,
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Somerville V, Schowing T, Chabas H, Schmidt RS, von Ah U, Bruggmann R, Engel P. Extensive diversity and rapid turnover of phage defense repertoires in cheese-associated bacterial communities. Microbiome 2022; 10:137. [PMID: 36028909 PMCID: PMC9419375 DOI: 10.1186/s40168-022-01328-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 07/17/2022] [Indexed: 05/14/2023]
Abstract
BACKGROUND Phages are key drivers of genomic diversity in bacterial populations as they impose strong selective pressure on the evolution of bacterial defense mechanisms across closely related strains. The pan-immunity model suggests that such diversity is maintained because the effective immune system of a bacterial species is the one distributed across all strains present in the community. However, only few studies have analyzed the distribution of bacterial defense systems at the community-level, mostly focusing on CRISPR and comparing samples from complex environments. Here, we studied 2778 bacterial genomes and 188 metagenomes from cheese-associated communities, which are dominated by a few bacterial taxa and occur in relatively stable environments. RESULTS We corroborate previous laboratory findings that in cheese-associated communities nearly identical strains contain diverse and highly variable arsenals of innate and adaptive (i.e., CRISPR-Cas) immunity systems suggesting rapid turnover. CRISPR spacer abundance correlated with the abundance of matching target sequences across the metagenomes providing evidence that the identified defense repertoires are functional and under selection. While these characteristics align with the pan-immunity model, the detected CRISPR spacers only covered a subset of the phages previously identified in cheese, providing evidence that CRISPR does not enable complete immunity against all phages, and that the innate immune mechanisms may have complementary roles. CONCLUSIONS Our findings show that the evolution of bacterial defense mechanisms is a highly dynamic process and highlight that experimentally tractable, low complexity communities such as those found in cheese, can help to understand ecological and molecular processes underlying phage-defense system relationships. These findings can have implications for the design of robust synthetic communities used in biotechnology and the food industry. Video Abstract.
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Affiliation(s)
- Vincent Somerville
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
- Agroscope, Bern, Switzerland.
| | - Thibault Schowing
- Agroscope, Bern, Switzerland
- Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern, Bern, Switzerland
| | - Hélène Chabas
- Institute for Integrative Biology, ETH Zürich, Zürich, Switzerland
| | | | | | - Rémy Bruggmann
- Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern, Bern, Switzerland
| | - Philipp Engel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
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Somerville V, Berthoud H, Schmidt RS, Bachmann HP, Meng YH, Fuchsmann P, von Ah U, Engel P. Functional strain redundancy and persistent phage infection in Swiss hard cheese starter cultures. ISME J 2022; 16:388-399. [PMID: 34363005 PMCID: PMC8776748 DOI: 10.1038/s41396-021-01071-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/14/2021] [Accepted: 07/15/2021] [Indexed: 02/07/2023]
Abstract
Undefined starter cultures are poorly characterized bacterial communities from environmental origin used in cheese making. They are phenotypically stable and have evolved through domestication by repeated propagation in closed and highly controlled environments over centuries. This makes them interesting for understanding eco-evolutionary dynamics governing microbial communities. While cheese starter cultures are known to be dominated by a few bacterial species, little is known about the composition, functional relevance, and temporal dynamics of strain-level diversity. Here, we applied shotgun metagenomics to an important Swiss cheese starter culture and analyzed historical and experimental samples reflecting 82 years of starter culture propagation. We found that the bacterial community is highly stable and dominated by only a few coexisting strains of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. lactis. Genome sequencing, metabolomics analysis, and co-culturing experiments of 43 isolates show that these strains are functionally redundant, but differ tremendously in their phage resistance potential. Moreover, we identified two highly abundant Streptococcus phages that seem to stably coexist in the community without any negative impact on bacterial growth or strain persistence, and despite the presence of a large and diverse repertoire of matching CRISPR spacers. Our findings show that functionally equivalent strains can coexist in domesticated microbial communities and highlight an important role of bacteria-phage interactions that are different from kill-the-winner dynamics.
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Affiliation(s)
- Vincent Somerville
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
- Agroscope, Bern, Switzerland.
| | | | | | | | | | | | | | - Philipp Engel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
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Somerville V, Berthoud H, Schmidt RS, Bachmann HP, Meng YH, Fuchsmann P, von Ah U, Engel P. Functional strain redundancy and persistent phage infection in Swiss hard cheese starter cultures. ISME J 2022; 16:388-399. [PMID: 34363005 DOI: 10.1101/2021.01.14.426499v2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/14/2021] [Accepted: 07/15/2021] [Indexed: 05/27/2023]
Abstract
Undefined starter cultures are poorly characterized bacterial communities from environmental origin used in cheese making. They are phenotypically stable and have evolved through domestication by repeated propagation in closed and highly controlled environments over centuries. This makes them interesting for understanding eco-evolutionary dynamics governing microbial communities. While cheese starter cultures are known to be dominated by a few bacterial species, little is known about the composition, functional relevance, and temporal dynamics of strain-level diversity. Here, we applied shotgun metagenomics to an important Swiss cheese starter culture and analyzed historical and experimental samples reflecting 82 years of starter culture propagation. We found that the bacterial community is highly stable and dominated by only a few coexisting strains of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. lactis. Genome sequencing, metabolomics analysis, and co-culturing experiments of 43 isolates show that these strains are functionally redundant, but differ tremendously in their phage resistance potential. Moreover, we identified two highly abundant Streptococcus phages that seem to stably coexist in the community without any negative impact on bacterial growth or strain persistence, and despite the presence of a large and diverse repertoire of matching CRISPR spacers. Our findings show that functionally equivalent strains can coexist in domesticated microbial communities and highlight an important role of bacteria-phage interactions that are different from kill-the-winner dynamics.
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Affiliation(s)
- Vincent Somerville
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
- Agroscope, Bern, Switzerland.
| | | | | | | | | | | | | | - Philipp Engel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
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Shani N, Oberhaensli S, Berthoud H, Schmidt RS, Bachmann HP. Antimicrobial Susceptibility of Lactobacillus delbrueckii subsp. lactis from Milk Products and Other Habitats. Foods 2021; 10:foods10123145. [PMID: 34945696 PMCID: PMC8701367 DOI: 10.3390/foods10123145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
As components of many cheese starter cultures, strains of Lactobacillus delbrueckii subsp. lactis (LDL) must be tested for their antimicrobial susceptibility to avoid the potential horizontal transfer of antibiotic resistance (ABR) determinants in the human body or in the environment. To this end, a phenotypic test, as well as a screening for antibiotic resistance genes (ARGs) in genome sequences, is commonly performed. Historically, microbiological cutoffs (MCs), which are used to classify strains as either 'sensitive' or 'resistant' based on the minimal inhibitory concentrations (MICs) of a range of clinically-relevant antibiotics, have been defined for the whole group of the obligate homofermentative lactobacilli, which includes LDL among many other species. This often leads to inaccuracies in the appreciation of the ABR status of tested LDL strains and to false positive results. To define more accurate MCs for LDL, we analyzed the MIC profiles of strains originating from various habitats by using the broth microdilution method. These strains' genomes were sequenced and used to complement our analysis involving a search for ARGs, as well as to assess the phylogenetic proximity between strains. Of LDL strains, 52.1% displayed MICs that were higher than the defined MCs for kanamycin, 9.9% for chloramphenicol, and 5.6% for tetracycline, but no ARG was conclusively detected. On the other hand, all strains displayed MICs below the defined MCs for ampicillin, gentamycin, erythromycin, and clindamycin. Considering our results, we propose the adaptation of the MCs for six of the tested clinically-relevant antibiotics to improve the accuracy of phenotypic antibiotic testing.
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Affiliation(s)
- Noam Shani
- Competence Division Methods Development and Analytics, Agroscope, Schwarzenburgstrasse 161, 3003 Bern, Switzerland;
- Correspondence:
| | - Simone Oberhaensli
- Interfaculty Bioinformatics Unit and SIB Swiss Institute of Bioinformatics, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland;
| | - Hélène Berthoud
- Competence Division Methods Development and Analytics, Agroscope, Schwarzenburgstrasse 161, 3003 Bern, Switzerland;
| | - Remo S. Schmidt
- Research Division Food Microbial Systems, Agroscope, Schwarzenburgstrasse 161, 3003 Bern, Switzerland; (R.S.S.); (H.-P.B.)
| | - Hans-Peter Bachmann
- Research Division Food Microbial Systems, Agroscope, Schwarzenburgstrasse 161, 3003 Bern, Switzerland; (R.S.S.); (H.-P.B.)
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Brand M, Wang L, Agnello S, Gazzola S, Gall FM, Raguž L, Kaiser M, Schmidt RS, Ritschl A, Jelk J, Hemphill A, Mäser P, Bütikofer P, Adams M, Riedl R. Back Cover: Antiprotozoal Structure–Activity Relationships of Synthetic Leucinostatin Derivatives and Elucidation of their Mode of Action (Angew. Chem. Int. Ed. 28/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/anie.202104896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Michael Brand
- Institute of Chemistry and Biotechnology Center for Organic and Medicinal Chemistry Zurich University of Applied Sciences (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Switzerland
| | - Lei Wang
- Institute of Biochemistry and Molecular Medicine University of Bern Bühlstrasse 28 3012 Bern Switzerland
| | - Stefano Agnello
- Institute of Chemistry and Biotechnology Center for Organic and Medicinal Chemistry Zurich University of Applied Sciences (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Switzerland
| | - Silvia Gazzola
- Institute of Chemistry and Biotechnology Center for Organic and Medicinal Chemistry Zurich University of Applied Sciences (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Switzerland
| | - Flavio M. Gall
- Institute of Chemistry and Biotechnology Center for Organic and Medicinal Chemistry Zurich University of Applied Sciences (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Switzerland
| | - Luka Raguž
- Institute of Chemistry and Biotechnology Center for Organic and Medicinal Chemistry Zurich University of Applied Sciences (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Switzerland
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute Socinstrasse 57 4051 Basel Switzerland
- University of Basel Petersplatz 1 4001 Basel Switzerland
| | - Remo S. Schmidt
- Swiss Tropical and Public Health Institute Socinstrasse 57 4051 Basel Switzerland
- University of Basel Petersplatz 1 4001 Basel Switzerland
| | - Amélie Ritschl
- Swiss Tropical and Public Health Institute Socinstrasse 57 4051 Basel Switzerland
- University of Basel Petersplatz 1 4001 Basel Switzerland
| | - Jennifer Jelk
- Institute of Biochemistry and Molecular Medicine University of Bern Bühlstrasse 28 3012 Bern Switzerland
| | - Andrew Hemphill
- Institute of Parasitology Vetsuisse Faculty University of Bern Länggass-Strasse 122 3012 Bern Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute Socinstrasse 57 4051 Basel Switzerland
- University of Basel Petersplatz 1 4001 Basel Switzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine University of Bern Bühlstrasse 28 3012 Bern Switzerland
| | - Michael Adams
- Bacoba AG Elisabethenstrasse 15 4051 Basel Switzerland
| | - Rainer Riedl
- Institute of Chemistry and Biotechnology Center for Organic and Medicinal Chemistry Zurich University of Applied Sciences (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Switzerland
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10
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Brand M, Wang L, Agnello S, Gazzola S, Gall FM, Raguž L, Kaiser M, Schmidt RS, Ritschl A, Jelk J, Hemphill A, Mäser P, Bütikofer P, Adams M, Riedl R. Antiprotozoische Struktur‐Aktivitäts‐Beziehungen von synthetischen Leucinostatin‐Derivaten und Aufklärung ihres Wirkprinzips. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael Brand
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
| | - Lei Wang
- Institut für Biochemie und Molekulare Medizin Universität Bern Bühlstrasse 28 3012 Bern Schweiz
| | - Stefano Agnello
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
| | - Silvia Gazzola
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
| | - Flavio M. Gall
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
| | - Luka Raguž
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
| | - Marcel Kaiser
- Schweizerisches Tropen- und Public Health-Institut Socinstrasse 57 4051 Basel Schweiz
- University of Basel Petersplatz 1 4001 Basel Schweiz
| | - Remo S. Schmidt
- Schweizerisches Tropen- und Public Health-Institut Socinstrasse 57 4051 Basel Schweiz
- University of Basel Petersplatz 1 4001 Basel Schweiz
| | - Amélie Ritschl
- Schweizerisches Tropen- und Public Health-Institut Socinstrasse 57 4051 Basel Schweiz
- University of Basel Petersplatz 1 4001 Basel Schweiz
| | - Jennifer Jelk
- Institut für Biochemie und Molekulare Medizin Universität Bern Bühlstrasse 28 3012 Bern Schweiz
| | - Andrew Hemphill
- Institut für Parasitologie Vetsuisse Fakultät Universität Bern Länggass-Strasse 122 3012 Bern Schweiz
| | - Pascal Mäser
- Schweizerisches Tropen- und Public Health-Institut Socinstrasse 57 4051 Basel Schweiz
- University of Basel Petersplatz 1 4001 Basel Schweiz
| | - Peter Bütikofer
- Institut für Biochemie und Molekulare Medizin Universität Bern Bühlstrasse 28 3012 Bern Schweiz
| | | | - Rainer Riedl
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
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11
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Brand M, Wang L, Agnello S, Gazzola S, Gall FM, Raguž L, Kaiser M, Schmidt RS, Ritschl A, Jelk J, Hemphill A, Mäser P, Bütikofer P, Adams M, Riedl R. Antiprotozoal Structure-Activity Relationships of Synthetic Leucinostatin Derivatives and Elucidation of their Mode of Action. Angew Chem Int Ed Engl 2021; 60:15613-15621. [PMID: 33730410 PMCID: PMC8360131 DOI: 10.1002/anie.202102153] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/13/2021] [Indexed: 12/15/2022]
Abstract
Leucinostatin A is one of the most potent antiprotozoal compounds ever described, but little was known on structure-activity relationships (SAR). We used Trypanosoma brucei as a protozoal model organism to test synthetically modified derivatives, resulting in simplified but equally active compounds 2 (ZHAWOC6025) and 4 (ZHAWOC6027), which were subsequently modified in all regions of the molecule to gain an in-depth SAR understanding. The antiprotozoal SAR matched SAR in phospholipid liposomes, where membrane integrity, leaking, and dynamics were studied. The mode of action is discussed based on a structure-activity analysis of derivatives in efficacy, ultrastructural studies in T. brucei, and artificial membrane models, mimicking membrane stability and membrane potential. The main site of antiprotozoal action of natural and synthetic leucinostatins lies in the destabilization of the inner mitochondrial membrane, as demonstrated by ultrastructural analysis, electron microscopy and mitochondrial staining. Long-time sublethal exposure of T. brucei (200 passages) and siRNA screening of 12'000 mutants showed no signs of resistance development to the synthetic derivatives.
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Affiliation(s)
- Michael Brand
- Institute of Chemistry and BiotechnologyCenter for Organic and Medicinal ChemistryZurich University of Applied Sciences (ZHAW)Einsiedlerstrasse 318820WädenswilSwitzerland
| | - Lei Wang
- Institute of Biochemistry and Molecular MedicineUniversity of BernBühlstrasse 283012BernSwitzerland
| | - Stefano Agnello
- Institute of Chemistry and BiotechnologyCenter for Organic and Medicinal ChemistryZurich University of Applied Sciences (ZHAW)Einsiedlerstrasse 318820WädenswilSwitzerland
| | - Silvia Gazzola
- Institute of Chemistry and BiotechnologyCenter for Organic and Medicinal ChemistryZurich University of Applied Sciences (ZHAW)Einsiedlerstrasse 318820WädenswilSwitzerland
| | - Flavio M. Gall
- Institute of Chemistry and BiotechnologyCenter for Organic and Medicinal ChemistryZurich University of Applied Sciences (ZHAW)Einsiedlerstrasse 318820WädenswilSwitzerland
| | - Luka Raguž
- Institute of Chemistry and BiotechnologyCenter for Organic and Medicinal ChemistryZurich University of Applied Sciences (ZHAW)Einsiedlerstrasse 318820WädenswilSwitzerland
| | - Marcel Kaiser
- Swiss Tropical and Public Health InstituteSocinstrasse 574051BaselSwitzerland
- University of BaselPetersplatz 14001BaselSwitzerland
| | - Remo S. Schmidt
- Swiss Tropical and Public Health InstituteSocinstrasse 574051BaselSwitzerland
- University of BaselPetersplatz 14001BaselSwitzerland
| | - Amélie Ritschl
- Swiss Tropical and Public Health InstituteSocinstrasse 574051BaselSwitzerland
- University of BaselPetersplatz 14001BaselSwitzerland
| | - Jennifer Jelk
- Institute of Biochemistry and Molecular MedicineUniversity of BernBühlstrasse 283012BernSwitzerland
| | - Andrew Hemphill
- Institute of ParasitologyVetsuisse FacultyUniversity of BernLänggass-Strasse 1223012BernSwitzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health InstituteSocinstrasse 574051BaselSwitzerland
- University of BaselPetersplatz 14001BaselSwitzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular MedicineUniversity of BernBühlstrasse 283012BernSwitzerland
| | | | - Rainer Riedl
- Institute of Chemistry and BiotechnologyCenter for Organic and Medicinal ChemistryZurich University of Applied Sciences (ZHAW)Einsiedlerstrasse 318820WädenswilSwitzerland
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12
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Brand M, Wang L, Agnello S, Gazzola S, Gall FM, Raguž L, Kaiser M, Schmidt RS, Ritschl A, Jelk J, Hemphill A, Mäser P, Bütikofer P, Adams M, Riedl R. Rücktitelbild: Antiprotozoische Struktur‐Aktivitäts‐Beziehungen von synthetischen Leucinostatin‐Derivaten und Aufklärung ihres Wirkprinzips (Angew. Chem. 28/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202104896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Michael Brand
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
| | - Lei Wang
- Institut für Biochemie und Molekulare Medizin Universität Bern Bühlstrasse 28 3012 Bern Schweiz
| | - Stefano Agnello
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
| | - Silvia Gazzola
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
| | - Flavio M. Gall
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
| | - Luka Raguž
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
| | - Marcel Kaiser
- Schweizerisches Tropen- und Public Health-Institut Socinstrasse 57 4051 Basel Schweiz
- University of Basel Petersplatz 1 4001 Basel Schweiz
| | - Remo S. Schmidt
- Schweizerisches Tropen- und Public Health-Institut Socinstrasse 57 4051 Basel Schweiz
- University of Basel Petersplatz 1 4001 Basel Schweiz
| | - Amélie Ritschl
- Schweizerisches Tropen- und Public Health-Institut Socinstrasse 57 4051 Basel Schweiz
- University of Basel Petersplatz 1 4001 Basel Schweiz
| | - Jennifer Jelk
- Institut für Biochemie und Molekulare Medizin Universität Bern Bühlstrasse 28 3012 Bern Schweiz
| | - Andrew Hemphill
- Institut für Parasitologie Vetsuisse Fakultät Universität Bern Länggass-Strasse 122 3012 Bern Schweiz
| | - Pascal Mäser
- Schweizerisches Tropen- und Public Health-Institut Socinstrasse 57 4051 Basel Schweiz
- University of Basel Petersplatz 1 4001 Basel Schweiz
| | - Peter Bütikofer
- Institut für Biochemie und Molekulare Medizin Universität Bern Bühlstrasse 28 3012 Bern Schweiz
| | | | - Rainer Riedl
- Institut für Chemie und Biotechnologie Fachstelle Pharmazeutische Wirkstoffforschung und Arzneimittelentwicklung Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) Einsiedlerstrasse 31 8820 Wädenswil Schweiz
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13
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Walther B, Guggisberg D, Schmidt RS, Portmann R, Risse MC, Badertscher R, Chollet M. Quantitative analysis of menaquinones (vitamin K2) in various types of cheese from Switzerland. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2020.104853] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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14
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Giovanoli Evack J, Schmidt RS, Boltryk SD, Voss TS, Batil AA, Ngandolo BN, Greter H, Utzinger J, Zinsstag J, Balmer O. Molecular Confirmation of a Fasciola gigantica × Fasciola hepatica Hybrid in a Chadian Bovine. J Parasitol 2020; 106:316-322. [PMID: 32330281 DOI: 10.1645/19-66] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Fascioliasis is a zoonotic infection of humans and, more commonly, ruminants. It is caused by 2 liver fluke species, Fasciola hepatica and Fasciola gigantica, which differ in size. The traditional morphological methods used to distinguish the 2 species can be unreliable, particularly in the presence of hybrids between the 2 species. The development of advanced molecular methods has allowed for more definitive identification of Fasciola species, including their hybrids. Hybrids are of concern, as it is thought that they could acquire advantageous traits such as increased pathogenicity and host range. In 2013, we collected flukes from Fasciola-positive cattle, sheep, and goats slaughtered in 4 Chadian abattoirs. DNA from 27 flukes was extracted, amplified, and analyzed to identify species using the ITS1+2 locus. Twenty-six of the 27 flukes were identified as F. gigantica, while the remaining fluke showed heterozygosity at all variable sites that distinguish F. hepatica and F. gigantica. Cloning and sequencing of both alleles confirmed the presence of 1 F. hepatica and 1 F. gigantica allele. To our knowledge, this is the first unambiguous, molecular demonstration of the presence of such a hybrid in a bovine in sub-Saharan Africa.
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Affiliation(s)
- Jennifer Giovanoli Evack
- Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4051 Basel, Switzerland.,University of Basel, Petersplatz 1, CH-4001 Basel, Switzerland
| | - Remo S Schmidt
- Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4051 Basel, Switzerland.,University of Basel, Petersplatz 1, CH-4001 Basel, Switzerland
| | - Sylwia D Boltryk
- Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4051 Basel, Switzerland.,University of Basel, Petersplatz 1, CH-4001 Basel, Switzerland
| | - Till S Voss
- Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4051 Basel, Switzerland.,University of Basel, Petersplatz 1, CH-4001 Basel, Switzerland
| | - Annour A Batil
- Institut de Recherche en Elevage pour le Développement, Boîte Postale 473, N'Djamena, Chad
| | - Bongo N Ngandolo
- Institut de Recherche en Elevage pour le Développement, Boîte Postale 473, N'Djamena, Chad
| | - Helena Greter
- Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4051 Basel, Switzerland.,University of Basel, Petersplatz 1, CH-4001 Basel, Switzerland
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4051 Basel, Switzerland.,University of Basel, Petersplatz 1, CH-4001 Basel, Switzerland
| | - Jakob Zinsstag
- Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4051 Basel, Switzerland.,University of Basel, Petersplatz 1, CH-4001 Basel, Switzerland
| | - Oliver Balmer
- Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4051 Basel, Switzerland.,University of Basel, Petersplatz 1, CH-4001 Basel, Switzerland
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15
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Wenger A, Schmidt RS, Portmann R, Roetschi A, Eugster E, Weisskopf L, Irmler S. Identification of a species-specific aminotransferase in Pediococcus acidilactici capable of forming α-aminobutyrate. AMB Express 2020; 10:100. [PMID: 32472439 PMCID: PMC7260336 DOI: 10.1186/s13568-020-01034-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 05/23/2020] [Indexed: 11/19/2022] Open
Abstract
During cheese ripening, the bacterial strain Pediococcus acidilactici FAM18098 produces the non-proteinogenic amino acid, α-aminobutyrate (AABA). The metabolic processes that lead to the biosynthesis of this compound are unknown. In this study, 10 P. acidilactici, including FAM18098 and nine Pediococcus pentosaceus strains, were screened for their ability to produce AABA. All P. acidilactici strains produced AABA, whereas the P. pentosaceus strains did not. The genomes of the pediococcal strains were sequenced and searched for genes encoding aminotransferases to test the hypothesis that AABA could result from the transamination of α-ketobutyrate. A GenBank and KEGG database search revealed the presence of a species-specific aminotransferase in P. acidilactici. The gene was cloned and its gene product was produced as a His-tagged fusion protein in Escherichia coli to determine the substrate specificity of this enzyme. The purified recombinant protein showed aminotransferase activity at pH 5.5. It catalyzed the transfer of the amino group from leucine, methionine, AABA, alanine, cysteine, and phenylalanine to the amino group acceptor α-ketoglutarate. Αlpha-ketobutyrate could replace α-ketoglutarate as an amino group acceptor. In this case, AABA was produced at significantly higher levels than glutamate. The results of this study show that P. acidilactici possesses a novel aminotransferase that might play a role in cheese biochemistry and has the potential to be used in biotechnological processes for the production of AABA.
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Affiliation(s)
- Alexander Wenger
- Agroscope, Schwarzenburgstrasse 161, 3003, Bern, Switzerland.,Department of Biology, University of Fribourg, Rue Albert-Gockel 3, 1700, Fribourg, Switzerland
| | - Remo S Schmidt
- Agroscope, Schwarzenburgstrasse 161, 3003, Bern, Switzerland
| | - Reto Portmann
- Agroscope, Schwarzenburgstrasse 161, 3003, Bern, Switzerland
| | | | - Elisabeth Eugster
- Bern University of Applied Sciences, School of Agricultural, Forest, and Food Sciences HAFL, Länggasse 85, 3052, Zollikofen, Switzerland
| | - Laure Weisskopf
- Department of Biology, University of Fribourg, Rue Albert-Gockel 3, 1700, Fribourg, Switzerland
| | - Stefan Irmler
- Agroscope, Schwarzenburgstrasse 161, 3003, Bern, Switzerland.
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16
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Jourdan J, Walz A, Matile H, Schmidt A, Wu J, Wang X, Dong Y, Vennerstrom JL, Schmidt RS, Wittlin S, Mäser P. Stochastic Protein Alkylation by Antimalarial Peroxides. ACS Infect Dis 2019; 5:2067-2075. [PMID: 31626733 DOI: 10.1021/acsinfecdis.9b00264] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Antimalarial peroxides such as the phytochemical artemisinin or the synthetic ozonides arterolane and artefenomel undergo reductive cleavage of the pharmacophoric peroxide bond by ferrous heme, released by parasite hemoglobin digestion. The generated carbon-centered radicals alkylate heme in an intramolecular reaction and proteins in an intermolecular reaction. Here, we determine the proteinaceous alkylation signatures of artemisinin and synthetic ozonides in Plasmodium falciparum using alkyne click chemistry probes to identify target proteins by affinity purification and mass spectrometry-based proteomics. Using stringent controls and purification procedures, we identified 25 P. falciparum proteins that were alkylated by the antimalarial peroxides in a peroxide-dependent manner, but the alkylation patterns were more random than we had anticipated. Moreover, there was little overlap in the alkylation signatures identified in this work and those disclosed in previous studies. Our findings suggest that alkylation of parasite proteins by antimalarial peroxides is likely to be a nonspecific, stochastic process.
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Affiliation(s)
- Joëlle Jourdan
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Annabelle Walz
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Hugues Matile
- F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Alexander Schmidt
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Jianbo Wu
- College of Pharmacy, University of Nebraska Medical Center, 42nd and Emile, Omaha, Nebraska 68198-6125, United States
| | - Xiaofang Wang
- College of Pharmacy, University of Nebraska Medical Center, 42nd and Emile, Omaha, Nebraska 68198-6125, United States
| | - Yuxiang Dong
- College of Pharmacy, University of Nebraska Medical Center, 42nd and Emile, Omaha, Nebraska 68198-6125, United States
| | - Jonathan L. Vennerstrom
- College of Pharmacy, University of Nebraska Medical Center, 42nd and Emile, Omaha, Nebraska 68198-6125, United States
| | - Remo S. Schmidt
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Sergio Wittlin
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
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17
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Steinmann ME, Schmidt RS, Macêdo JP, Kunz Renggli C, Bütikofer P, Rentsch D, Mäser P, Sigel E. Identification and characterization of the three members of the CLC family of anion transport proteins in Trypanosoma brucei. PLoS One 2017; 12:e0188219. [PMID: 29244877 PMCID: PMC5731698 DOI: 10.1371/journal.pone.0188219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/02/2017] [Indexed: 11/19/2022] Open
Abstract
CLC type anion transport proteins are homo-dimeric or hetero-dimeric with an integrated transport function in each subunit. We have identified and partially characterized three members of this family named TbVCL1, TbVCL2 and TbVCL3 in Trypanosoma brucei. Among the human CLC family members, the T. brucei proteins display highest similarity to CLC-6 and CLC-7. TbVCL1, but not TbVCL2 and TbVCL3 is able to complement growth of a CLC-deficient Saccharomyces cerevisiae mutant. All TbVCL-HA fusion proteins localize intracellulary in procyclic form trypanosomes. TbVCL1 localizes close to the Golgi apparatus and TbVCL2 and TbVCL3 to the endoplasmic reticulum. Upon expression in Xenopus oocytes, all three proteins induce similar outward rectifying chloride ion currents. Currents are sensitive to low concentrations of DIDS, insensitive to the pH in the range 5.4 to 8.4 and larger in nitrate than in chloride medium.
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Affiliation(s)
- Michael E. Steinmann
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Remo S. Schmidt
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Juan P. Macêdo
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Christina Kunz Renggli
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Doris Rentsch
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Erwin Sigel
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- * E-mail:
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18
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Wiedemar N, Graf FE, Zwyer M, Ndomba E, Kunz Renggli C, Cal M, Schmidt RS, Wenzler T, Mäser P. Beyond immune escape: a variant surface glycoprotein causes suramin resistance in Trypanosoma brucei. Mol Microbiol 2017; 107:57-67. [PMID: 28963732 DOI: 10.1111/mmi.13854] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2017] [Indexed: 11/27/2022]
Abstract
Suramin is one of the first drugs developed in a medicinal chemistry program (Bayer, 1916), and it is still the treatment of choice for the hemolymphatic stage of African sleeping sickness caused by Trypanosoma brucei rhodesiense. Cellular uptake of suramin occurs by endocytosis, and reverse genetic studies with T. b. brucei have linked downregulation of the endocytic pathway to suramin resistance. Here we show that forward selection for suramin resistance in T. brucei spp. cultures is fast, highly reproducible and linked to antigenic variation. Bloodstream-form trypanosomes are covered by a dense coat of variant surface glycoprotein (VSG), which protects them from their mammalian hosts' immune defenses. Each T. brucei genome contains over 2000 different VSG genes, but only one is expressed at a time. An expression switch to one particular VSG, termed VSGSur , correlated with suramin resistance. Reintroduction of the originally expressed VSG gene in resistant T. brucei restored suramin susceptibility. This is the first report of a link between antigenic variation and drug resistance in African trypanosomes.
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Affiliation(s)
- Natalie Wiedemar
- Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland.,University of Basel, Basel CH-4001, Switzerland
| | - Fabrice E Graf
- Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland.,University of Basel, Basel CH-4001, Switzerland
| | - Michaela Zwyer
- Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland.,University of Basel, Basel CH-4001, Switzerland
| | - Emiliana Ndomba
- Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland.,University of Basel, Basel CH-4001, Switzerland
| | - Christina Kunz Renggli
- Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland.,University of Basel, Basel CH-4001, Switzerland
| | - Monica Cal
- Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland.,University of Basel, Basel CH-4001, Switzerland
| | - Remo S Schmidt
- Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland.,University of Basel, Basel CH-4001, Switzerland
| | - Tanja Wenzler
- Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland.,University of Basel, Basel CH-4001, Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland.,University of Basel, Basel CH-4001, Switzerland
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19
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Schmidt RS, Macêdo JP, Steinmann ME, Salgado AG, Bütikofer P, Sigel E, Rentsch D, Mäser P. Transporters of Trypanosoma brucei-phylogeny, physiology, pharmacology. FEBS J 2017; 285:1012-1023. [PMID: 29063677 DOI: 10.1111/febs.14302] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/18/2017] [Accepted: 10/18/2017] [Indexed: 12/12/2022]
Abstract
Trypanosoma brucei comprise the causative agents of sleeping sickness, T. b. gambiense and T. b. rhodesiense, as well as the livestock-pathogenic T. b. brucei. The parasites are transmitted by the tsetse fly and occur exclusively in sub-Saharan Africa. T. brucei are not only lethal pathogens but have also become model organisms for molecular parasitology. We focus here on membrane transport proteins of T. brucei, their contribution to homeostasis and metabolism in the context of a parasitic lifestyle, and their pharmacological role as potential drug targets or routes of drug entry. Transporters and channels in the plasma membrane are attractive drug targets as they are accessible from the outside. Alternatively, they can be exploited to selectively deliver harmful substances into the trypanosome's interior. Both approaches require the targeted transporter to be essential: in the first case to kill the trypanosome, in the second case to prevent drug resistance due to loss of the transporter. By combining functional and phylogenetic analyses, we were mining the T. brucei predicted proteome for transporters of pharmacological significance. Here, we review recent progress in the identification of transporters of lipid precursors, amino acid permeases and ion channels in T. brucei.
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Affiliation(s)
- Remo S Schmidt
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | - Juan P Macêdo
- Institute of Plant Sciences, University of Bern, Switzerland
| | - Michael E Steinmann
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland
| | | | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland
| | - Erwin Sigel
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland
| | - Doris Rentsch
- Institute of Plant Sciences, University of Bern, Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
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Mathieu C, Macêdo JP, Hürlimann D, Wirdnam C, Haindrich AC, Suter Grotemeyer M, González-Salgado A, Schmidt RS, Inbar E, Mäser P, Bütikofer P, Zilberstein D, Rentsch D. Arginine and Lysine Transporters Are Essential for Trypanosoma brucei. PLoS One 2017; 12:e0168775. [PMID: 28045943 PMCID: PMC5207785 DOI: 10.1371/journal.pone.0168775] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 12/06/2016] [Indexed: 12/14/2022] Open
Abstract
For Trypanosoma brucei arginine and lysine are essential amino acids and therefore have to be imported from the host. Heterologous expression in Saccharomyces cerevisiae mutants identified cationic amino acid transporters among members of the T. brucei AAAP (amino acid/auxin permease) family. TbAAT5-3 showed high affinity arginine uptake (Km 3.6 ± 0.4 μM) and high selectivity for L-arginine. L-arginine transport was reduced by a 10-times excess of L-arginine, homo-arginine, canavanine or arginine-β-naphthylamide, while lysine was inhibitory only at 100-times excess, and histidine or ornithine did not reduce arginine uptake rates significantly. TbAAT16-1 is a high affinity (Km 4.3 ± 0.5 μM) and highly selective L-lysine transporter and of the compounds tested, only L-lysine and thialysine were competing for L-lysine uptake. TbAAT5-3 and TbAAT16-1 are expressed in both procyclic and bloodstream form T. brucei and cMyc-tagged proteins indicate localization at the plasma membrane. RNAi-mediated down-regulation of TbAAT5 and TbAAT16 in bloodstream form trypanosomes resulted in growth arrest, demonstrating that TbAAT5-mediated arginine and TbAAT16-mediated lysine transport are essential for T. brucei. Growth of induced RNAi lines could partially be rescued by supplementing a surplus of arginine or lysine, respectively, while addition of both amino acids was less efficient. Single and double RNAi lines indicate that additional low affinity uptake systems for arginine and lysine are present in T. brucei.
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Affiliation(s)
| | - Juan P. Macêdo
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Daniel Hürlimann
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Corina Wirdnam
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | | | | | | | - Remo S. Schmidt
- Swiss Tropical and Public Health Institute and University of Basel, Basel, Switzerland
| | - Ehud Inbar
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute and University of Basel, Basel, Switzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Dan Zilberstein
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Doris Rentsch
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
- * E-mail:
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Graf FE, Ludin P, Arquint C, Schmidt RS, Schaub N, Kunz Renggli C, Munday JC, Krezdorn J, Baker N, Horn D, Balmer O, Caccone A, de Koning HP, Mäser P. Comparative genomics of drug resistance in Trypanosoma brucei rhodesiense. Cell Mol Life Sci 2016; 73:3387-400. [PMID: 26973180 PMCID: PMC4967103 DOI: 10.1007/s00018-016-2173-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 03/01/2016] [Indexed: 12/02/2022]
Abstract
Trypanosoma brucei rhodesiense is one of the causative agents of human sleeping sickness, a fatal disease that is transmitted by tsetse flies and restricted to Sub-Saharan Africa. Here we investigate two independent lines of T. b. rhodesiense that have been selected with the drugs melarsoprol and pentamidine over the course of 2 years, until they exhibited stable cross-resistance to an unprecedented degree. We apply comparative genomics and transcriptomics to identify the underlying mutations. Only few mutations have become fixed during selection. Three genes were affected by mutations in both lines: the aminopurine transporter AT1, the aquaporin AQP2, and the RNA-binding protein UBP1. The melarsoprol-selected line carried a large deletion including the adenosine transporter gene AT1, whereas the pentamidine-selected line carried a heterozygous point mutation in AT1, G430R, which rendered the transporter non-functional. Both resistant lines had lost AQP2, and both lines carried the same point mutation, R131L, in the RNA-binding motif of UBP1. The finding that concomitant deletion of the known resistance genes AT1 and AQP2 in T. b. brucei failed to phenocopy the high levels of resistance of the T. b. rhodesiense mutants indicated a possible role of UBP1 in melarsoprol–pentamidine cross-resistance. However, homozygous in situ expression of UBP1-Leu131 in T. b. brucei did not affect the sensitivity to melarsoprol or pentamidine.
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Affiliation(s)
- Fabrice E Graf
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Philipp Ludin
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Christian Arquint
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Remo S Schmidt
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Nadia Schaub
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Christina Kunz Renggli
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Jane C Munday
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jessica Krezdorn
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Nicola Baker
- Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK.,The University of Kent, Canterbury, Kent, CT2 7NZ, UK
| | - David Horn
- Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Oliver Balmer
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Adalgisa Caccone
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland. .,University of Basel, 4000, Basel, Switzerland.
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Schmidt RS, Bütikofer P. Autophagy in Trypanosoma brucei: amino acid requirement and regulation during different growth phases. PLoS One 2014; 9:e93875. [PMID: 24699810 PMCID: PMC3974859 DOI: 10.1371/journal.pone.0093875] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 03/11/2014] [Indexed: 01/10/2023] Open
Abstract
Autophagy in the protozoan parasite, Trypanosoma brucei, may be involved in differentiation between different life cycle forms and during growth in culture. We have generated multiple parasite cell lines stably expressing green fluorescent protein- or hemagglutinin-tagged forms of the autophagy marker proteins, TbAtg8.1 and TbAtg8.2, in T. brucei procyclic forms to establish a trypanosome system for quick and reliable determination of autophagy under different culture conditions using flow cytometry. We found that starvation-induced autophagy in T. brucei can be inhibited by addition of a single amino acid, histidine, to the incubation buffer. In addition, we show that autophagy is induced when parasites enter stationary growth phase in culture and that their capacity to undergo starvation-induced autophagy decreases with increasing cell density.
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Affiliation(s)
- Remo S. Schmidt
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- * E-mail:
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Jelk J, Gao N, Serricchio M, Signorell A, Schmidt RS, Bangs JD, Acosta-Serrano A, Lehrman MA, Bütikofer P, Menon AK. Glycoprotein biosynthesis in a eukaryote lacking the membrane protein Rft1. J Biol Chem 2013; 288:20616-23. [PMID: 23720757 PMCID: PMC3711325 DOI: 10.1074/jbc.m113.479642] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 05/21/2013] [Indexed: 12/13/2022] Open
Abstract
Mature dolichol-linked oligosaccharides (mDLOs) needed for eukaryotic protein N-glycosylation are synthesized by a multistep pathway in which the biosynthetic lipid intermediate Man5GlcNAc2-PP-dolichol (M5-DLO) flips from the cytoplasmic to the luminal face of the endoplasmic reticulum. The endoplasmic reticulum membrane protein Rft1 is intimately involved in mDLO biosynthesis. Yeast genetic analyses implicated Rft1 as the M5-DLO flippase, but because biochemical tests challenged this assignment, the function of Rft1 remains obscure. To understand the role of Rft1, we sought to analyze mDLO biosynthesis in vivo in the complete absence of the protein. Rft1 is essential for yeast viability, and no Rft1-null organisms are currently available. Here, we exploited Trypanosoma brucei (Tb), an early diverging eukaryote whose Rft1 homologue functions in yeast. We report that TbRft1-null procyclic trypanosomes grow nearly normally. They have normal steady-state levels of mDLO and significant N-glycosylation, indicating robust M5-DLO flippase activity. Remarkably, the mutant cells have 30-100-fold greater steady-state levels of M5-DLO than wild-type cells. All N-glycans in the TbRft1-null cells originate from mDLO indicating that the M5-DLO excess is not available for glycosylation. These results suggest that rather than facilitating M5-DLO flipping, Rft1 facilitates conversion of M5-DLO to mDLO by another mechanism, possibly by acting as an M5-DLO chaperone.
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Affiliation(s)
- Jennifer Jelk
- the Institute of Biochemistry and Molecular Medicine,
University of Bern, 3012 Bern, Switzerland
| | - Ningguo Gao
- the Department of Pharmacology, University of Texas
Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Mauro Serricchio
- the Institute of Biochemistry and Molecular Medicine,
University of Bern, 3012 Bern, Switzerland
| | - Aita Signorell
- From the Department of Biochemistry, Weill Cornell Medical
College, New York, New York 10065
| | - Remo S. Schmidt
- the Institute of Biochemistry and Molecular Medicine,
University of Bern, 3012 Bern, Switzerland
| | - James D. Bangs
- the Department of Microbiology and Immunology, School of
Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214,
and
| | - Alvaro Acosta-Serrano
- the Parasitology and Vector Biology Departments,
Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Mark A. Lehrman
- the Department of Pharmacology, University of Texas
Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Peter Bütikofer
- the Institute of Biochemistry and Molecular Medicine,
University of Bern, 3012 Bern, Switzerland
| | - Anant K. Menon
- From the Department of Biochemistry, Weill Cornell Medical
College, New York, New York 10065
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Macêdo JP, Schmidt RS, Mäser P, Rentsch D, Vial HJ, Sigel E, Bütikofer P. Characterization of choline uptake in Trypanosoma brucei procyclic and bloodstream forms. Mol Biochem Parasitol 2013; 190:16-22. [PMID: 23747277 DOI: 10.1016/j.molbiopara.2013.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 05/27/2013] [Accepted: 05/28/2013] [Indexed: 10/26/2022]
Abstract
Choline is an essential nutrient for eukaryotic cells, where it is used as precursor for the synthesis of choline-containing phospholipids, such as phosphatidylcholine (PC). According to published data, Trypanosoma brucei parasites are unable to take up choline from the environment but instead use lyso-phosphatidylcholine as precursor for choline lipid synthesis. We now show that T. brucei procyclic forms in culture readily incorporate [(3)H]-labeled choline into PC, indicating that trypanosomes express a transporter for choline at the plasma membrane. Characterization of the transport system in T. brucei procyclic and bloodstream forms shows that uptake of choline is independent of sodium and potassium ions and occurs with a Km in the low micromolar range. In addition, we demonstrate that choline uptake can be blocked by the known choline transport inhibitor, hemicholinium-3, and by synthetic choline analogs that have been established as anti-malarials. Together, our results show that T. brucei parasites express an uptake system for choline and that exogenous choline is used for PC synthesis.
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Affiliation(s)
- Juan P Macêdo
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland
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Schmidt RS. Rearing of crickets in quantity for feeding lab animals. Contemp Top Lab Anim Sci 1993; 33:19-20. [PMID: 16468700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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Abstract
Neural correlates of mating calling and pulmonary respiration were recorded from isolated brain stems of male Northern leopard frogs (Rana p. pipiens) before and after exposure of the brain stems to prostaglandin F2 alpha (PG) or saline. Diffusion of PG (but not saline) from a pipette directly over the pretrigeminal nuclei abolished "calling" temporarily. Similar application of PG nearby had no effect. Exposure of only the anterior 1/2 of the brain stem, containing the pretrigeminal nuclei but not the pulmonary respiration generator, to PG (but not saline) abolished generation of slow waves by the pretrigeminal nucleus portion of the mating calling pattern generator. Exposure of only the posterior 1/2 of the brain stem, containing the pulmonary respiration generator but not the pretrigeminal nuclei, to PG had no effect on the correlates of pulmonary respiration. These results are consistent with the hypothesis that the inhibition of calling by PG is through an effect largely, perhaps exclusively, on the pretrigeminal nuclei.
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Affiliation(s)
- R S Schmidt
- Department of Pharmacology, Loyola University of Chicago Stitch School of Medicine, Maywood, Illinois 60153
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Abstract
The anterior preoptic nuclei of the isolated brainstem of male, Northern leopard frogs (Rana p. pipiens) were stimulated electrically and neural correlates of mating calling recorded from the rhombencephalic mating calling pattern generator. Lesions of discrete areas of the brainstem showed that the mating calling generator is separable into two generators, the pretrigeminal nucleus and the classical pulmonary respiration generator (which is approximately co-extensive with the motor nuclei IX-X). Each of these still can produce pulses when isolated from the other. Their interaction changes the expiratory phase of breathing into the vocal phase of calling. All stages of intermediates between these phases could be seen. An updated and simplified model of call production and evolution is presented.
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Affiliation(s)
- R S Schmidt
- Department of Pharmacology, Loyola University of Chicago Stritch School of Medicine, Maywood, IL
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Schmidt RS, Kemnitz CP, Hudson WR. Origin of anuran calling: description of toad releasing. J Exp Zool 1990; 254:338-42. [PMID: 2345350 DOI: 10.1002/jez.1402540314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Electromyographic electrodes were implanted in forelimb muscles of male American toads (Bufo americanus). Toads then were allowed to clasp an artificial clasp object incorporating a pair of solenoids that, when activated, produced a stimulus simulating the side vibrations normally associated with release signalling by conspecific males. Electromyographic activity, in response to the release stimulus, was recorded. The adductor muscle contracted immediately after stimulus onset (causing intensified clasping), responding to the stimulus as a displacement threat. Then the abductor muscle contracted (causing rapid unclasping, or releasing), responding to the stimulus as a release signal. These techniques have provided a better understanding of releasing than has been possible with natural objects (i.e., living males).
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Affiliation(s)
- R S Schmidt
- Neuropharmacology Institute, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois 60153
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Affiliation(s)
- R S Schmidt
- Neuropharmacology Institute, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153
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Abstract
Release signals (chirps and side vibrations) are given by a male toad being clasped by another toad. These signals trigger immediate releasing (i.e. unclasping) by the clasping toad. First, small electrolytic lesions in the lateral subtoral tegmentum of male American toads abolished releasing, i.e. these toads persisted in clasping release-signaling males. Second, stimulation of this area caused bilateral abduction of the forelimbs, as occurs in normal releasing. Third, neural responses, resulting from tactile stimulation of either thumbpad, could be recorded from this region. Supposedly, similar stimuli would be generated by the release vibrations of the sides given by a male being clasped. These data are consistent with the participation of the lateral subtoral tegmentum in the detection of release signals and in the triggering of releasing. Release signaling was probably an important step in the evolution of anuran vocalizations. The midbrain tegmentum may contain primitive circuits for the detection of stimuli eliciting anuran acoustic behaviors.
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Affiliation(s)
- R S Schmidt
- Department of Pharmacology, Loyola University, Chicago Stritch School of Medicine, Maywood, Ill
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Abstract
Male American toads (Bufo americanus) were induced to mating call in response to electronically simulated, conspecific mating calls. The injection of prostaglandin (PG) F2 alpha caused suppression of mating call answering. Neural correlates of mating calling were triggered by electrical stimulation of the anterior preoptic nucleus in the isolated brainstem of male, Northern leopard frogs (Rana p. pipiens). The addition of PGF2 alpha to the bath completely abolished the correlates of mating calling without changing the correlates of pulmonary respiration. The suppression of mating calling shown here, along with the suppression of release signalling described by Diakow and Nemiroff (1981), supports the hypothesis of a close interrelation between the neural circuits of these two calls. The suppression of the neural correlates of mating calling in an isolated preparation shows a central site of action of the PG. The retention of normal correlates of pulmonary respiration, even after suppression of mating calling correlates, suggests that the generation of mating calling patterns involves the extension and pulsing of the expiratory phase of breathing.
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Affiliation(s)
- R S Schmidt
- Neuropharmacology Institute, Loyola University of Chicago, Stritch School of Medicine, Maywood, Illinois 60153
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Abstract
Lesions of the preoptic area and immediately adjacent septal area were made in female American toads, Bufo americanus. The ability to show mating call phonotaxis (MCP) was then tested for. The intensity of MCP was found to decrease as the degree of damage to the anterior tip of the anterior preoptic nucleus (APON) increased. The APON is known to concentrate androgens and to be essential for mating calling by male anurans. Perhaps the APON is involved also in the detection of the elevated levels of prostaglandin associated with MCP. Even in lesioned toads in which phonotaxis was nearly absent, there was an occasional MCP response that seemed entirely normal. Therefore, the APON is not involved in generating or guiding the motor mechanisms of phonotaxis.
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Affiliation(s)
- R S Schmidt
- Neuropharmacology Institute, Loyola University of Chicago, Stritch School of Medicine, Maywood, Illinois 60153
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Abstract
Female American toads were tested for mating call phonotaxis (prostaglandin-induced) after brain lesions. The pretrigeminal nucleus, all of the telencephalon (except the preoptic area and immediately adjacent septal area), the dorsal thalamus (including all of the anterior nuclei and most of the central nuclei), the optic tectum, and the dorsal and medial parts of the torus were removed without interferring with the hormonal sensitization, acoustic triggering, or production of phonotaxis. These lesions removed most of the forebrain and much of the midbrain auditory areas. These data are compared with similar lesion data on the triggering mechanisms for three other anuran acoustic behaviors. The lateral subtoral tegmentum may have a basic, special importance in the triggering of all four behaviours.
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Affiliation(s)
- R S Schmidt
- Department of Pharmacology, Loyola University of Chicago Stritch School of Medicine, Maywood, Ill
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Abstract
Gravid, female American toads are known to move toward conspecific mating calls. This behavior, as well as ovulation, often can be induced by the injection of human chorionic gonadotropin (HCG). It was found that HCG-induced phonotaxis could be terminated by the injection of indomethacin (an inhibitor of prostaglandin synthesis) and then reinstated by the injection of prostaglandin F2 alpha. A drug regimen was devised that allowed elicitation of phonotaxis, indistinguishable from that induced by HCG and in the absence of ovulation. This involved the administration of prostaglandin F2 alpha and arginine vasotocin (or mesotocin) following progesterone priming. It has not been determined whether the peptide is really essential.
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Abstract
Neural correlates of mating calling can be recorded from isolated brainstems of male, Northern leopard frogs after the circuits for this behavior have been triggered by electrical stimulation of the preoptic area. Correlates can be evoked reliably and by a stimulus of low amplitude. However, such correlates can be evoked only rarely from female brainstems, and then only by a much larger stimulus. The sensitivity to triggering in female brainstems can be masculinized by previous treatment of the intact frog with testosterone propionate or dihydrotestosterone, but not by estradiol benzoate. This suggests that the action of the androgens is direct and does not require aromatization to estrogens. Comparisons with other studies suggest that the androgen effect may be mainly on posterior parts of the calling circuits (i.e., call pattern generator or motoneurons), rather than on the preoptic area trigger of the generator.
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Abstract
The anuran (toad and frog) pretrigeminal nucleus is probably involved in the production of vocalizations, including the male mating call. This nucleus is especially obvious when stained by the succinic dehydrogenase method. In the American toad, a striking sexual dimorphism is shown by such staining. The male nucleus contains numerous, large cells that stain intensely. Such cells are smaller and infrequent in females.
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Abstract
The magnocellular portion of the pretrigeminal nucleus (a structure involved in vocalization) of male toads contains large cells than does the female nucleus. Testosterone propionate injections caused essentially complete, and dihydrotestosterone injections incomplete, mascullinization of the female nucleus. Estradiol benzoate injections had little or no effect. The androgen effects are therefore largely direct rather than involving extensive aromatization of androgen to estrogen.
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Abstract
After injection of 14C-2-deoxy-D-glucose, some leopard frogs were induced to release call repeatedly, while others were used as silent controls. Autoradiograms of brains of many of the calling frogs, but none of the silent ones, showed heavy labeling of the pretrigeminal nucleus. This supports the hypothesis that this nucleus is involved in release calling.
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Abstract
Neurons that take up 3H-noradrenaline were detected, by autoradiography, around the ventral tip of the isthmic nucleus in treefrogs. No uptake was detected in the adjacent pretrigeminal nucleus, suggesting that this is not homologous to the locus coeruleus.
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Schmidt RS, Hudson WR. A minimum-volume, flow-through system for rearing frog tadpoles: aquarium. Lab Anim Sci 1979; 29:525-7. [PMID: 316042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A flow-through system requiring a low flow rate (4-10 ml/minute/aquarium) was developed for rearing tadpoles. This permitted tadpoles to be raised in tap water that had been dechlorinated and acidified. The aquarium consisted of a 7-liter plastic outer shell. A screen-bottomed basket, inserted into the shell, facilitated handling of the tadpoles. A bottom-scraper and flushing system permitted periodic removal of solid wastes.
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Schmidt RS. [Experimental studies of the prenatal toxic effect of Halan]. Z Gesamte Hyg 1977; 23:623-6. [PMID: 930146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Abstract
AbstractThe tendency to clasp is increased greatly, in the toad Bufo cognatus, by injections of gonadotrophin. In B. americanus, the forebrain and medial parts of the inferior colliculi are not necessary for releasing (i.e. unclasping) behavior. Small lesions at the lateral edge of the anterio-dorsal nucleus of the inferior colliculi abolish releasing. After removal of the clasp-inhibition mechanisms of the trigemino-isthmic tegmentum, toads show strong clasping (foreleg adduction) and strong releasing (hindleg kicking) movements simultaneously. This suggests that releasing is a distinct behavior pattern, rather than merely an inhibition of clasping Normal releasing can be evoked in B. americanus after complete bilateral labyrinthectomy, and the presence of a nearby, release-calling male does not evoke releasing by a clasping male. Therefore, it must be mainly the tactile effects, rather than the auditory or vestibular effects, of the release signals that evoke releasing. The effects of section of the dorsal roots of various spinal nerves in B. americanus confirm that the foreleg is the most important area for reception of the tactile stimuli evoking clasping and releasing. Gross lesions of the forefoot and sections of various nerves to the forefoot show that receptors involved in eliciting these behaviors are widely distributed in this area. The forefoot sensory field of the deep radial nerve is especially involved in clasping.
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Abstract
AbstractTechniques are described for inducing ovulation in tree frogs (Hyla cinerea) and toads (Bufo woodhousei fowleri) and for testing the ability of these gravid females to orient to homospecific mating calls. A few preliminary tests were also made with heterospecific mating calls. Several responses to calls are described. Of special interest is an escape response made by Bufo to heterospecific calls. This may serve as an isolating mechanism by effecting avoidance of heterospecific calling males. Males of the same species could not be induced to move toward mating calls. Testing of females with forebrain lesions showed that the telencephalon and the dorsal part of the preoptic area are not necessary for orientation behavior, but that the region of the ventral magnocellular preoptic nucleus is essential.
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Abstract
AbstractRelease calling and warning crying in Rana pipiens are described and compared with breathing. Vokalizations consist of a vocal phase, which is merely a modification of the expiratory phase of breathing, followed by an inspiratory phase, which is identical to inspiratory phase of breathing. Electrical and mechanical stimulation of the brain and brain lesions are used to locate some of the central mechanisms controlling release calling and warning crying in Rana pipiens, and mating calling in Rana pipiens and a number of hylids (mainly Hyla cinerea). It is concluded that the main control mechanisms are in the trigeminoisthmic tegmentum (below the nucleus isthmi). Mating calling requires, in addition, input transmitted through the ventral thalamus from hormone receptors in the preoptic area. Mating calling can be evoked in hylids by presenting them with recordings of specific calls. The mechanisms for responding to an acoustic stimulus are probably located in the anterior medulla and midbrain tegmentum (below the nucleus isthmi). Mating calling was evoked in two Hyla cinerea females after replacing the ovaries with Rana testes and injecting Rana pituitaries. It is suggested that release calling evolved from breathing, and that warning crying and mating calling may then have evolved from release calling.
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