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Biezuner T, Brilon Y, Arye AB, Oron B, Kadam A, Danin A, Furer N, Minden MD, Hwan Kim DD, Shapira S, Arber N, Dick J, Thavendiranathan P, Moskovitz Y, Kaushansky N, Chapal-Ilani N, Shlush LI. An improved molecular inversion probe based targeted sequencing approach for low variant allele frequency. NAR Genom Bioinform 2022; 4:lqab125. [PMID: 35156021 PMCID: PMC8826764 DOI: 10.1093/nargab/lqab125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 11/25/2021] [Accepted: 01/25/2022] [Indexed: 11/23/2022] Open
Abstract
Deep targeted sequencing technologies are still not widely used in clinical practice due to the complexity of the methods and their cost. The Molecular Inversion Probes (MIP) technology is cost effective and scalable in the number of targets, however, suffers from low overall performance especially in GC rich regions. In order to improve the MIP performance, we sequenced a large cohort of healthy individuals (n = 4417), with a panel of 616 MIPs, at high depth in duplicates. To improve the previous state-of-the-art statistical model for low variant allele frequency, we selected 4635 potentially positive variants and validated them using amplicon sequencing. Using machine learning prediction tools, we significantly improved precision of 10–56.25% (P < 0.0004) to detect variants with VAF > 0.005. We further developed biochemically modified MIP protocol and improved its turn-around-time to ∼4 h. Our new biochemistry significantly improved uniformity, GC-Rich regions coverage, and enabled 95% on target reads in a large MIP panel of 8349 genomic targets. Overall, we demonstrate an enhancement of the MIP targeted sequencing approach in both detection of low frequency variants and in other key parameters, paving its way to become an ultrafast cost-effective research and clinical diagnostic tool.
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Affiliation(s)
- Tamir Biezuner
- Department of Immunology, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Yardena Brilon
- Department of Immunology, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Asaf Ben Arye
- Department of Statistics and Operations Research, Tel Aviv University, Ramat Aviv, Israel
| | - Barak Oron
- Department of Immunology, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Aditee Kadam
- Department of Immunology, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Adi Danin
- Department of Immunology, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Nili Furer
- Department of Immunology, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Mark D Minden
- Princess Margaret Cancer Centre, University Health Network (UHN), Department of Medical Oncology & Hematology, Toronto, ON, Canada
| | - Dennis Dong Hwan Kim
- Princess Margaret Cancer Centre, University Health Network (UHN), Department of Medical Oncology & Hematology, Toronto, ON, Canada
| | | | | | - John Dick
- Princess Margaret Cancer Centre, University Health Network (UHN), Department of Molecular Genetics, Toronto, ON, Canada
| | - Paaladinesh Thavendiranathan
- Department of Medicine, Division of Cardiology, Ted Rogers Program in Cardiotoxicity Prevention, Peter Munk Cardiac Center, Toronto General Hospital, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Yoni Moskovitz
- Department of Immunology, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Nathali Kaushansky
- Department of Immunology, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Noa Chapal-Ilani
- Department of Immunology, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Liran I Shlush
- Department of Immunology, Weizmann Institute of Science, Rehovot 761001, Israel
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Kapach G, Nuri R, Schmidt C, Danin A, Ferrera S, Savidor A, Gerlach RG, Shai Y. Loss of the Periplasmic Chaperone Skp and Mutations in the Efflux Pump AcrAB-TolC Play a Role in Acquired Resistance to Antimicrobial Peptides in Salmonella typhimurium. Front Microbiol 2020; 11:189. [PMID: 32210923 PMCID: PMC7075815 DOI: 10.3389/fmicb.2020.00189] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [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: 10/30/2019] [Accepted: 01/27/2020] [Indexed: 01/01/2023] Open
Abstract
Bacterial resistance to antibiotics is a major concern worldwide, leading to an extensive search for alternative drugs. Promising candidates are antimicrobial peptides (AMPs), innate immunity molecules, shown to be highly efficient against multidrug resistant bacteria. Therefore, it is essential to study bacterial resistance mechanisms against them. For that purpose, we used experimental evolution, and isolated a Salmonella enterica serovar typhimurium-resistant line to the AMP 4DK5L7. This AMP displayed promising features including widespread activity against Gram-negative bacteria and protection from proteolytic degradation. However, the resistance that evolved in the isolated strain was particularly high. Whole genome sequencing revealed that five spontaneous mutations had evolved. Of these, three are novel in the context of acquired AMP resistance. Two mutations are related to the AcrAB-TolC multidrug efflux pump. One occurred in AcrB, the substrate-binding domain of the system, and the second in RamR, a transcriptional regulator of the system. Together, the mutations increased the minimal inhibitory concentration (MIC) by twofold toward this AMP. Moreover, the mutation in AcrB induced hypersusceptibility toward ampicillin and colistin. The last mutation occurred in Skp, a periplasmic chaperone that participates in the biogenesis of outer membrane proteins (OMPs). This mutation increased the MIC by twofold to 4DK5L7 and by fourfold to another AMP, seg5D. Proteomic analysis revealed that the mutation abolished Skp expression, reduced OMP abundance, and increased DegP levels. DegP, a protease that was reported to have an additional chaperone activity, escorts OMPs through the periplasm along with Skp, but is also associated with AMP resistance. In conclusion, our data demonstrate that both loss of Skp and manipulation of the AcrAB-TolC system are alternative strategies of AMP acquired resistance in Salmonella typhimurium and might represent a common mechanism in other Gram-negative bacteria.
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Affiliation(s)
- Gal Kapach
- Departmant of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Reut Nuri
- Departmant of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | | | - Adi Danin
- Departmant of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Shir Ferrera
- Departmant of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Alon Savidor
- de Botton Institute for Protein Profiling, The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, Israel
| | - Roman G Gerlach
- Project Group 5, Robert Koch Institute, Wernigerode, Germany
| | - Yechiel Shai
- Departmant of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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Hungate B, Danin A, Pellerin NB, Stemmler J, Kjellander P, Adams JB, Staley JT. Characterization of manganese-oxidizing (MnII→MnIV) bacteria from Negev Desert rock varnish: implications in desert varnish formation. Can J Microbiol 1987. [DOI: 10.1139/m87-165] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A collection of 79 bacterial isolates was obtained by plating scrapings and swabs from five rock varnish samples of the Negev Desert, Israel. Of the bacterial isolates which were obtained, 74 were able to oxidize manganese (MnII→MnIV) under laboratory conditions. The manganese-oxidizing bacteria were characterized and identified, when possible, to genus. The predominant genera were Bacillus, Geodermatophilus, Arthrobacter, and Micrococcus. Examples of all of these genera were found from more than one rock. These same genera have been reported from manganese-rich rock varnish samples from the Sonoran and Mojave Deserts of North America; however, many of the strains (species?) from the Negev appear to be different from those of the American Southwest. A single manganese-oxidizing actinomycete was also isolated. The high percentage of manganese-oxidizing bacteria to total cultivable bacteria (83 to 100% depending upon sample) from the Negev suggests that they are involved in desert varnish formation.
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Vogel JC, Fuls A, Danin A. Geographical and environmental distribution of C 3 and C 4 grasses in the Sinai, Negev, and Judean deserts. Oecologia 1986; 70:258-265. [PMID: 28311667 DOI: 10.1007/bf00379249] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [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: 12/01/1985] [Indexed: 10/26/2022]
Abstract
The relation between photosynthetic pathway and habitat of the grass species recorded in the desert regions of Sinai, Negev, and Judea was investigated. The climatic conditions and micro-environments in the study area vary considerably, and the distribution of the various species is found to conform to specific patterns which reveal the adaptive advantages of the different photosynthetic pathways. There is also a distinct correlation between the phytogeographic origin of the grass species and the photosynthetic pathways that they utilize.The survey shows that the majority of the grass species in the region are of the C3 type and all except one of these species belong to the Holarctic domain. This is in accordance with the fact that the region forms part of the Mediterranean winter rainfall regime and that C3 species have an adaptive advantage where minimum temperatures are low during the winter growing season.The occurence of C4 species increases with decreasing rainfall and they dominate in those districts where temperatures are high throughout the year. These C4 grasses are of both Holarctic and Palaeotropic origin according to the classification adopted here, but they are essentially all elements of the Saharo-Arabian, Irano-Turanian, Sudanian, or Tropical phytogeographic regions and are not typical of the Mediterranean or Euro-Siberian floras. The plants with multi-regional distributions that occur in Mediterranean communities may well be intrusive.Analysis of the three subtypes of the C4 species suggests that the malate-forming NADP-me grasses grow where water stress is not a dominating factor, while the aspartateforming NAD-me grasses are more successful under xeric conditions. The PEP-ck species are not abundant and form an intermediate group between the NADP-me and NAD-me subtypes.
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Affiliation(s)
- J C Vogel
- National Physical Research Laboratory, CSIR, PO Box 395, Pretoria, South Africa
| | - A Fuls
- National Physical Research Laboratory, CSIR, PO Box 395, Pretoria, South Africa
| | - A Danin
- Department of Botany, The Hebrew University of Jerusalem, 91904, Jerusalem, Israel
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