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Start Over Author "Savidor A" Publisher american society for microbiology
6 results on '"Savidor A"'

1. High Levels of CO 2 Induce Spoilage by Leuconostoc mesenteroides by Upregulating Dextran Synthesis Genes

Author

Alon Savidor, Shlomo Sela, Paula Teper-Bamnolker, Avinoam Daus, Dani Eshel, Yael Lampert, Noa Sela, Barak Dror, Shmuel Carmeli, and Bolaji Babajide Salam

Subjects
Exudate, 0303 health sciences, Ecology, biology, 030306 microbiology, Chemistry, Lactobacillales, Food spoilage, food and beverages, biology.organism_classification, Applied Microbiology and Biotechnology, Dextransucrase, 03 medical and health sciences, chemistry.chemical_compound, Dextran, Leuconostoc mesenteroides, medicine, Leuconostoc, Food science, medicine.symptom, Bacteria, Food Science, Biotechnology
Abstract

During nonventilated storage of carrots, CO2 gradually accumulates to high levels and causes modifications in the carrot9s microbiome toward dominance of Lactobacillales and Enterobacteriales. The lactic acid bacterium Leuconostoc mesenteroides secretes a slimy exudate over the surface of the carrots. The objective of this study was to characterize the slime components and the potential cause for its secretion under high CO2 levels. A proteomic analysis of the exudate revealed bacterial glucosyltransferases as the main proteins, specifically, dextransucrase. A chemical analysis of the exudate revealed high levels of dextran and several simple sugars. The exudate volume and dextran amount were significantly higher when L. mesenteroides was incubated under high CO2 levels than when incubated in an aerated environment. The treatment of carrot medium plates with commercial dextransucrase or exudate protein extract resulted in similar sugar profiles and dextran production. Transcriptome analysis demonstrated that dextran production is related to the upregulation of the L. mesenteroides dextransucrase-encoding genes dsrD and dsrT during the first 4 to 8 h of exposure to high CO2 levels compared to aerated conditions. A phylogenetic analysis of L. mesenteroides YL48 dsrD revealed a high similarity to other dsr genes harbored by different Leuconostoc species. The ecological benefit of dextran production under elevated CO2 requires further investigation. However, this study implies an overlooked role of CO2 in the physiology and fitness of L. mesenteroides in stored carrots, and perhaps in other food items, during storage under nonventilated conditions. IMPORTANCE The bacterium Leuconostoc mesenteroides is known to cause spoilage of different types of foods by secreting a slimy fluid that damages the quality and appearance of the produce. Here, we identified a potential mechanism by which high levels of CO2 affect the spoilage caused by this bacterium by upregulating dextran synthesis genes. These results have broader implications for the study of the physiology, degradation ability, and potential biotechnological applications of Leuconostoc.

Published
2019

3. Efficiency in Complexity: Composition and Dynamic Nature of Mimivirus Replication Factories

Author

Alon Savidor, Yael Mutsafi, Yishai Levin, Abraham Minsky, Yael Fridmann-Sirkis, Elena Kartvelishvily, Elad Milrot, and Shifra Ben-Dor

Subjects
0301 basic medicine, Mimivirus, biology, viruses, Structure and Assembly, Immunology, RNA, Computational biology, biology.organism_classification, Proteomics, Microbiology, Virology, Virus, 03 medical and health sciences, chemistry.chemical_compound, 030104 developmental biology, chemistry, Viral replication, Cytoplasm, Insect Science, Vaccinia, DNA
Abstract

The recent discovery of multiple giant double-stranded DNA (dsDNA) viruses blurred the consensual distinction between viruses and cells due to their size, as well as to their structural and genetic complexity. A dramatic feature revealed by these viruses as well as by many positive-strand RNA viruses is their ability to rapidly form elaborate intracellular organelles, termed “viral factories,” where viral progeny are continuously generated. Here we report the first isolation of viral factories at progressive postinfection time points. The isolated factories were subjected to mass spectrometry-based proteomics, bioinformatics, and imaging analyses. These analyses revealed that numerous viral proteins are present in the factories but not in mature virions, thus implying that multiple and diverse proteins are required to promote the efficiency of viral factories as “production lines” of viral progeny. Moreover, our results highlight the dynamic and highly complex nature of viral factories, provide new and general insights into viral infection, and substantiate the intriguing notion that viral factories may represent the living state of viruses. IMPORTANCE Large dsDNA viruses such as vaccinia virus and the giant mimivirus, as well as many positive-strand RNA viruses, generate elaborate cytoplasmic organelles in which the multiple and diverse transactions required for viral replication and assembly occur. These organelles, which were termed “viral factories,” are attracting much interest due to the increasing realization that the rapid and continuous production of viral progeny is a direct outcome of the elaborate structure and composition of the factories, which act as efficient production lines. To get new insights into the nature and function of viral factories, we devised a method that allows, for the first time, the isolation of these organelles. Analyses of the isolated factories generated at different times postinfection by mass spectrometry-based proteomics provide new perceptions of their role and reveal the highly dynamic nature of these organelles.

Published
2016

5. High Levels of CO2 Induce Spoilage by Leuconostoc mesenteroides by Upregulating Dextran-Synthesis Genes.

Author

Dror, Barak, Savidor, Alon, Salam, Bolaji Babajide, Sela, Noa, Lampert, Yael, Teper-Bamnolker, Paula, Daus, Avinoam, Carmeli, Shmuel, Sela (Saldinger), Shlomo, and Eshel, Dani

Subjects
*LEUCONOSTOC mesenteroides, *VEGETABLE storage, *FOOD spoilage, *GLYCOSYLTRANSFERASES, *EFFECT of carbon dioxide on plants
Abstract

During nonventilated storage of carrots, CO2 gradually accumulates to high levels and causes modifications in the carrot's microbiome toward dominance of Lactobacillales and Enterobacteriales. The lactic acid bacterium Leuconostoc mesenteroides secretes a slimy exudate over the surface of the carrots. The objective of this study was to characterize the slime components and the potential cause for its secretion under high CO2 levels. A proteomic analysis of the exudate revealed bacterial glucosyltransferases as the main proteins, specifically, dextransucrase. A chemical analysis of the exudate revealed high levels of dextran and several simple sugars. The exudate volume and dextran amount were significantly higher when L. mesenteroides was incubated under high CO2 levels than when incubated in an aerated environment. The treatment of carrot medium plates with commercial dextransucrase or exudate protein extract resulted in similar sugar profiles and dextran production. Transcriptome analysis demonstrated that dextran production is related to the upregulation of the L. mesenteroides dextransucrase-encoding genes dsrD and dsrT during the first 4 to 8-h of exposure to high CO2 levels compared to aerated conditions. A phylogenetic analysis of L. mesenteroides YL48 dsrD revealed a high similarity to other dsr genes harbored by different Leuconostoc species. The ecological benefit of dextran production under elevated CO2 requires further investigation. However, this study implies an overlooked role of CO2 in the physiology and fitness of L. mesenteroides in stored carrots, and perhaps in other food items, during storage under nonventilated conditions. IMPORTANCE The bacterium Leuconostoc mesenteroides is known to cause spoilage of different types of foods by secreting a slimy fluid that damages the quality and appearance of the produce. Here, we identified a potential mechanism by which high levels of CO2 affect the spoilage caused by this bacterium by upregulating dextran synthesis genes. These results have broader implications for the study of the physiology, degradation ability, and potential biotechnological applications of Leuconostoc. [ABSTRACT FROM AUTHOR]

Published
2019
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6. High Levels of CO 2 Induce Spoilage by Leuconostoc mesenteroides by Upregulating Dextran Synthesis Genes.

Author

Dror B, Savidor A, Salam BB, Sela N, Lampert Y, Teper-Bamnolker P, Daus A, Carmeli S, Sela Saldinger S, and Eshel D

Subjects
Bacterial Proteins metabolism, Daucus carota microbiology, Dextrans biosynthesis, Dextrans genetics, Food Storage, Genes, Bacterial, Glucosyltransferases metabolism, Leuconostoc mesenteroides enzymology, Phylogeny, Bacterial Proteins genetics, Carbon Dioxide metabolism, Glucosyltransferases genetics, Leuconostoc mesenteroides genetics, Up-Regulation
Abstract

During nonventilated storage of carrots, CO 2 gradually accumulates to high levels and causes modifications in the carrot's microbiome toward dominance of Lactobacillales and Enterobacteriales The lactic acid bacterium Leuconostoc mesenteroides secretes a slimy exudate over the surface of the carrots. The objective of this study was to characterize the slime components and the potential cause for its secretion under high CO 2 levels. A proteomic analysis of the exudate revealed bacterial glucosyltransferases as the main proteins, specifically, dextransucrase. A chemical analysis of the exudate revealed high levels of dextran and several simple sugars. The exudate volume and dextran amount were significantly higher when L. mesenteroides was incubated under high CO 2 levels than when incubated in an aerated environment. The treatment of carrot medium plates with commercial dextransucrase or exudate protein extract resulted in similar sugar profiles and dextran production. Transcriptome analysis demonstrated that dextran production is related to the upregulation of the L. mesenteroides dextransucrase-encoding genes dsrD and dsrT during the first 4 to 8 h of exposure to high CO 2 levels compared to aerated conditions. A phylogenetic analysis of L. mesenteroides YL48 dsrD revealed a high similarity to other dsr genes harbored by different Leuconostoc species. The ecological benefit of dextran production under elevated CO 2 requires further investigation. However, this study implies an overlooked role of CO 2 in the physiology and fitness of L. mesenteroides in stored carrots, and perhaps in other food items, during storage under nonventilated conditions. IMPORTANCE The bacterium Leuconostoc mesenteroides is known to cause spoilage of different types of foods by secreting a slimy fluid that damages the quality and appearance of the produce. Here, we identified a potential mechanism by which high levels of CO 2 affect the spoilage caused by this bacterium by upregulating dextran synthesis genes. These results have broader implications for the study of the physiology, degradation ability, and potential biotechnological applications of Leuconostoc ., (Copyright © 2018 American Society for Microbiology.)

Published
2018
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