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Ayada H, Dhioui B, Mazouz H, El Harrak A, Jaiti F, Ouhmidou B, Diouri M, Moumni M. In silico comparative genomic analysis unravels a new candidate protein arsenal specifically associated with Fusarium oxysporum f. sp. albedinis pathogenesis. Sci Rep 2022; 12:19098. [PMID: 36351932 PMCID: PMC9646873 DOI: 10.1038/s41598-022-21858-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/04/2022] [Indexed: 11/11/2022] Open
Abstract
Fusarium oxysporum f. sp albedinis (Foa) is a devastating fungus of date palms. To unravel the genetic characteristics associated with its pathogenesis, the two available genomes of Foa 133 and Foa 9 were compared with 49 genomes of 29 other pathogenic formae speciales belonging to Fusarium oxysporum species complex (FOSC). Foa 133 and Foa 9 have genomes of 56.23 Mb and 65.56 Mb with 17460 and 19514 putative coding genes. Of these genes, 30% lack functional annotation with no similarity to characterized proteins. The remaining genes were involved in pathways essential to the fungi's life and their adaptation. Foa secretome analysis revealed that both Foa strains possess an expanded number of secreted effectors (3003 in Foa 133 and 2418 in Foa 9). Those include effectors encoded by Foa unique genes that are involved in Foa penetration (Egh16-like family), host defense mechanisms suppression (lysM family) and pathogen protection (cysteine-rich protein family). The accessory protein SIX6, which induces plant cell death, was also predicted in Foa. Further analysis of secreted CAZymes revealed an arsenal of enzymes involved in plant cell wall degradation. This arsenal includes an exclusively Foa-specific CAZyme (GH5-7). Transcription factors and membrane transporters (MFS) involved in fungicide efflux have been predicted in Foa, in addition to a variety of secondary metabolites. These comprise mycotoxins as well as chrysogin, the latter provides Foa with resistance against adverse environmental conditions. Our results revealed new Foa proteins that could be targeted in future research in order to manage Bayoud disease.
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Affiliation(s)
- Hafida Ayada
- Biotechnology and Bioresources Valorization Laboratory, Biology Department, Faculty of Sciences, Moulay Ismail University of Meknès, Meknès, Morocco.
| | - Boutayna Dhioui
- Biotechnology and Bioresources Valorization Laboratory, Biology Department, Faculty of Sciences, Moulay Ismail University of Meknès, Meknès, Morocco
| | - Hamid Mazouz
- Biotechnology and Bioresources Valorization Laboratory, Biology Department, Faculty of Sciences, Moulay Ismail University of Meknès, Meknès, Morocco
| | - Abdelhay El Harrak
- Biotechnology and Bioresources Valorization Laboratory, Biology Department, Faculty of Sciences, Moulay Ismail University of Meknès, Meknès, Morocco
| | - Fatima Jaiti
- Biodiversity, Environment and Plant Protection Team, Faculty of Sciences and Technologies, Moulay Ismail University of Meknès, Meknès, Morocco
| | - Bouchra Ouhmidou
- Microbial biotechnology and bioactive molecules laboratory, Faculty of Sciences and Technologies, Sidi Mohammed Ben Abdellah University of Fez, Fez, Morocco
| | - Mohammed Diouri
- Biotechnology and Bioresources Valorization Laboratory, Biology Department, Faculty of Sciences, Moulay Ismail University of Meknès, Meknès, Morocco
| | - Mohieddine Moumni
- Biotechnology and Bioresources Valorization Laboratory, Biology Department, Faculty of Sciences, Moulay Ismail University of Meknès, Meknès, Morocco.
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Colpaert R, Petit Dit Grézériat L, Louzon M, de Vaufleury A, Gimbert F. Polyethylene microplastic toxicity to the terrestrial snail Cantareus aspersus: size matters. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:29258-29267. [PMID: 34462861 DOI: 10.1007/s11356-021-15824-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 08/01/2021] [Indexed: 06/13/2023]
Abstract
Plastic has become the most widespread human-made material and small fragments (< 5mm, so called microplastics, MPs) accumulate in all the ecosystems. It is now admitted that the terrestrial environment represents an important sink for MPs and it has only recently become the focus of research, notably in ecotoxicology. In spite of a growing body of evidence regarding the potential effects of MPs on soil biota, more efforts are needed to address issues in this field. The aim of our study was to measure, at different levels of biological organization, the responses of Cantareus aspersus snail to low-density polyethylene (LDPE) particles dispersed in their food. Juvenile snails were exposed to a range of LDPE concentrations (10, 25, and 50% v/v) and sizes (median particle size (d50) of 120, 292, 340, and 560 μm). This study showed no snail feeding avoidance toward LDPE. The ingestion and digestion processes along the snail digestive tract did not lead to a measurable fragmentation of the MP particles. At the individual scale, big sized particles improved growth at the lowest exposure concentration tested, whereas at the molecular level, only small sized particles triggered oxidative stress but without causing quantifiable cyto- or genotoxic effects. The underlying mechanisms remain to be elucidated which strengthens the necessity to improve our knowledge on the effects of MPs on various biological models to better evaluate their environmental risks in terrestrial environments.
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Affiliation(s)
- Romain Colpaert
- UMR CNRS 6249 Chrono-environnement, University of Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon Cedex, France
| | - Lucas Petit Dit Grézériat
- UMR CNRS 6249 Chrono-environnement, University of Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon Cedex, France
| | - Maxime Louzon
- UMR CNRS 6249 Chrono-environnement, University of Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon Cedex, France
| | - Annette de Vaufleury
- UMR CNRS 6249 Chrono-environnement, University of Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon Cedex, France
| | - Frédéric Gimbert
- UMR CNRS 6249 Chrono-environnement, University of Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon Cedex, France.
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Malgas S, Thoresen M, Moses V, Prinsloo E, Susan van Dyk J, Pletschke BI. Analysis of the galactomannan binding ability of β-mannosidases, BtMan2A and CmMan5A, regarding their activity and synergism with a β-mannanase. Comput Struct Biotechnol J 2022; 20:3140-3150. [PMID: 35782739 PMCID: PMC9232400 DOI: 10.1016/j.csbj.2022.06.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/14/2022] [Accepted: 06/14/2022] [Indexed: 11/28/2022] Open
Abstract
BtMan2A preferred short manno-oligomers, while CmMan5A preferred longer ones; DP >2. BtMan2A displayed stronger irreversible binding to galactomannan than CmMan5A. BtMan2A binding to galactomannan did not affect its activity, while CmMan5A lost activity. BtMan2A binding was pH-dependent, with increased binding ability at lower pH. CmMan5A synergised with CcManA, while BtMan2A did not – even though the enzyme was active. High loadings of BtMan2A abolished CcManA activity; at protein ratios ≥ 5:1.
Both β-mannanases and β-mannosidases are required for mannan-backbone degradation into mannose. In this study, two β-mannosidases of glycoside hydrolase (GH) families 2 (BtMan2A) and 5 (CmMan5A) were evaluated for their substrate specificities and galactomannan binding ability. BtMan2A preferred short manno-oligomers, while CmMan5A preferred longer ones; DP >2, and galactomannans. BtMan2A displayed irreversible galactomannan binding, which was pH-dependent, with higher binding observed at low pH, while CmMan5A had limited binding. Docking and molecular dynamics (MD) simulations showed that BtMan2A galactomannan binding was stronger under acidic conditions (-8.4 kcal/mol) than in a neutral environment (-7.6 kcal/mol), and the galactomannan ligand was more unstable under neutral conditions than acidic conditions. Qualitative surface plasmon resonance (SPR) experimentally confirmed the reduced binding capacity of BtMan2A at pH 7. Finally, synergistic β-mannanase to β-mannosidase (BtMan2A or CmMan5A) ratios required for maximal galactomannan hydrolysis were determined. All CcManA to CmMan5A combinations were synergistic (≈1.2-fold), while combinations of CcManA with BtMan2A (≈1.0-fold) yielded no hydrolysis improvement. In conclusion, the low specific activity of BtMan2A towards long and galactose-containing oligomers and its non-catalytic galactomannan binding ability led to no synergy with the mannanase, making GH2 mannosidases ineffective for use in cocktails for mannan degradation.
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Affiliation(s)
- Samkelo Malgas
- Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Makhanda, Eastern Cape 6140, South Africa
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield, Gauteng 0028, South Africa
- Corresponding author at: Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield, Gauteng 0028, South Africa.
| | - Mariska Thoresen
- Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Makhanda, Eastern Cape 6140, South Africa
| | - Vuyani Moses
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Makhanda, Eastern Cape 6140, South Africa
| | - Earl Prinsloo
- Biotechnology Innovation Centre, Rhodes University, Makhanda, Eastern Cape 6140, South Africa
| | - J. Susan van Dyk
- Forest Products Biotechnology, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia V6T1Z4, Canada
| | - Brett I. Pletschke
- Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Makhanda, Eastern Cape 6140, South Africa
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Gadea A, Charrier M, Fanuel M, Clerc P, Daugan C, Sauvager A, Rogniaux H, Boustie J, Le Lamer AC, Lohézic-Le Devehat F. Overcoming deterrent metabolites by gaining essential nutrients: A lichen/snail case study. PHYTOCHEMISTRY 2019; 164:86-93. [PMID: 31102999 DOI: 10.1016/j.phytochem.2019.04.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/19/2019] [Accepted: 04/27/2019] [Indexed: 06/09/2023]
Abstract
Specialised metabolites in lichens are generally considered repellent compounds by consumers. Nevertheless, if the only food available is lichens rich in specialised metabolites, lichenophages must implement strategies to overcome the toxicity of these metabolites. Thus, the balance between phagostimulant nutrients and deterrent metabolites could play a key role in feeding preferences. To further understand lichen-gastropod interactions, we studied the feeding behaviour and consumption in Notodiscus hookeri, the land snail native to sub-Antarctic islands. The lichen Usnea taylorii was used because of its simple chemistry, its richness in usnic acid (specialised metabolite) and arabitol (primary metabolite) and its presence in snail habitats. Choice tests in arenas with intact lichens versus acetone-rinsed lichens were carried out to study the influence of specialised metabolites on snail behaviour and feeding preference. Simultaneously, usnic acid and arabitol were quantified and located within the lichen thallus using HPLC-DAD-MS and in situ imaging by mass spectrometry to assess whether their spatial distribution explained preferential snail grazing. No-choice feeding experiments, with the pure metabolites embedded in an artificial diet, defined a gradual gustatory response, from strong repellence (usnic acid) to high appetence (D-arabitol). This case study demonstrates that the nutritional activity of N. hookeri is governed by the chemical quality of the food and primarily by nutrient availability (arabitol), despite the presence of deterrent metabolite (usnic acid).
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Affiliation(s)
- Alice Gadea
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, F-35000 Rennes, France; Univ Rennes, CNRS, ECOBIO (Ecosystèmes, Biodiversité, évolution), UMR 6553, F-35000 Rennes, France
| | - Maryvonne Charrier
- Univ Rennes, CNRS, ECOBIO (Ecosystèmes, Biodiversité, évolution), UMR 6553, F-35000 Rennes, France
| | - Mathieu Fanuel
- INRA, UR1268 Biopolymers Interactions Assemblies, F-44316 Nantes, France
| | - Philippe Clerc
- Conservatoire et Jardin Botanique, Département de la culture et du sport, chemin de l'impératrice 1, 1292, Chambésy, Switzerland
| | - Corentin Daugan
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, F-35000 Rennes, France
| | - Aurélie Sauvager
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, F-35000 Rennes, France
| | - Hélène Rogniaux
- INRA, UR1268 Biopolymers Interactions Assemblies, F-44316 Nantes, France
| | - Joël Boustie
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, F-35000 Rennes, France
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Gadea A, Le Lamer AC, Le Gall S, Jonard C, Ferron S, Catheline D, Ertz D, Le Pogam P, Boustie J, Lohézic-Le Devehat F, Charrier M. Intrathalline Metabolite Profiles in the Lichen Argopsis friesiana Shape Gastropod Grazing Patterns. J Chem Ecol 2018; 44:471-482. [PMID: 29611074 DOI: 10.1007/s10886-018-0953-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 11/29/2022]
Abstract
Lichen-gastropod interactions generally focus on the potential deterrent or toxic role of secondary metabolites. To better understand lichen-gastropod interactions, a controlled feeding experiment was designed to identify the parts of the lichen Argopsis friesiana consumed by the Subantarctic land snail Notodiscus hookeri. Besides profiling secondary metabolites in various lichen parts (apothecia, cephalodia, phyllocladia and fungal axis of the pseudopodetium), we investigated potentially beneficial resources that snails can utilize from the lichen (carbohydrates, amino acids, fatty acids, polysaccharides and total nitrogen). Notodiscus hookeri preferred cephalodia and algal layers, which had high contents of carbohydrates, nitrogen, or both. Apothecia were avoided, perhaps due to their low contents of sugars and polyols. Although pseudopodetia were characterized by high content of arabitol, they were also rich in medullary secondary compounds, which may explain why they were not consumed. Thus, the balance between nutrients (particularly nitrogen and polyols) and secondary metabolites appears to play a key role in the feeding preferences of this snail.
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Affiliation(s)
- Alice Gadea
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000, Rennes, France.,Univ Rennes, CNRS, ECOBIO (Ecosystèmes, Biodiversité, Evolution) - UMR 6553, F-35000, Rennes, France
| | - Anne-Cécile Le Lamer
- Univ Toulouse 3 Paul Sabatier, IRD, Pharma-Dev - UMR 152, F-31400, Toulouse, France
| | - Sophie Le Gall
- INRA, BIA (Biopolymers Interactions Assemblies) - UR 1268, F-44316, Nantes, France
| | - Catherine Jonard
- INRA, BIA (Biopolymers Interactions Assemblies) - UR 1268, F-35650, Le Rheu, France
| | - Solenn Ferron
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000, Rennes, France
| | - Daniel Catheline
- INRA, Agrocampus Ouest - USC 1378, F-35042, Rennes Cedex, France
| | - Damien Ertz
- Botanic Garden Meise, Department Research, Nieuwelaan 38, B-1860, Meise, Belgium
| | - Pierre Le Pogam
- Univ Rennes, CNRS, IETR (Institut d'Electronique et de Télécommunications de Rennes) - UMR 6164, F-35000, Rennes, France
| | - Joël Boustie
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000, Rennes, France
| | | | - Maryvonne Charrier
- Univ Rennes, CNRS, ECOBIO (Ecosystèmes, Biodiversité, Evolution) - UMR 6553, F-35000, Rennes, France.
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Nadaroglu H, Adiguzel G, Adiguzel A, Sonmez Z. A thermostable-endo-β-(1,4)-mannanase from Pediococcus acidilactici (M17): purification, characterization and its application in fruit juice clarification. Eur Food Res Technol 2016. [DOI: 10.1007/s00217-016-2735-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Ge JP, Du RP, Zhao D, Song G, Jin M, Ping WX. Bio-chemical characterization of a β-mannanase from Bacillus licheniformis HDYM-04 isolated from flax water-retting liquid and its decolorization ability of dyes. RSC Adv 2016. [DOI: 10.1039/c5ra25888j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A β-mannanase was purified from the bacteria,Bacillus licheniformisHDYM-04, which was a high β-mannanase-producing strain (576.16 U mL−1at 48 h during fermentation).
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Affiliation(s)
- J. P. Ge
- Key Laboratory of Microbiology
- College of Life Science
- Heilongjiang University
- Harbin 150080
- China
| | - R. P. Du
- Key Laboratory of Microbiology
- College of Life Science
- Heilongjiang University
- Harbin 150080
- China
| | - D. Zhao
- Key Laboratory of Microbiology
- College of Life Science
- Heilongjiang University
- Harbin 150080
- China
| | - G. Song
- Key Laboratory of Microbiology
- College of Life Science
- Heilongjiang University
- Harbin 150080
- China
| | - M. Jin
- Key Laboratory of Microbiology
- College of Life Science
- Heilongjiang University
- Harbin 150080
- China
| | - W. X. Ping
- Key Laboratory of Microbiology
- College of Life Science
- Heilongjiang University
- Harbin 150080
- China
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Adiguzel A, Nadaroglu H, Adiguzel G. Purification and characterization of [Formula: see text]-mannanase from Bacillus pumilus (M27) and its applications in some fruit juices. JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2015; 52:5292-5298. [PMID: 26243955 PMCID: PMC4519521 DOI: 10.1007/s13197-014-1609-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 09/08/2014] [Accepted: 10/13/2014] [Indexed: 10/24/2022]
Abstract
Thermo alkaline mannanase was purified from the bacteria of Bacillus pumilus (M27) using the techniques of ammonium sulphate precipitation, DEAE-Sephadex ion exchange chromatography and Sephacryl S200 gel filtration chromatography with 111-fold and 36 % yield. It was determined that the enzyme had 2 sub-units including 35 kDa and 55 kDa in gel filtration chromatography and SDS-PAGE electrophoresis systems. The optimum pH and temperature was determined as 8 and 60 °C, respectively. It was also noticed that the enzyme did not lose its activity at a wide interval such as pH 3-11 and at high temperatures such as 90 °C. Additionally, the effects of some metal ions on the mannanase enzyme activity. Moreover, the clarifying efficiency of purified mannanase enzyme with some fruit juices such as orange, apricot, grape and apple was also investigated. Enzymatic treatment was carried out with 1 mL L(-1) of purified mannanase for 1 h at 60 °C. It was determined that the highest pure enzyme was efficient upon clarifying the apple juice at 154 % rate.
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Affiliation(s)
- Ahmet Adiguzel
- />Faculty of Science, Department of Molecular Biology and Genetic, Ataturk University, 25240 Erzurum, Turkey
| | - Hayrunnisa Nadaroglu
- />Department of Food Technology, Erzurum Vocational Training School, Ataturk University, 25240 Erzurum, Turkey
| | - Gulsah Adiguzel
- />Department of Food Hygiene and Technology, Faculty of Veterinary, Ataturk University, 25240 Erzurum, Turkey
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A review of the enzymatic hydrolysis of mannans and synergistic interactions between β-mannanase, β-mannosidase and α-galactosidase. World J Microbiol Biotechnol 2015; 31:1167-75. [DOI: 10.1007/s11274-015-1878-2] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 05/23/2015] [Indexed: 10/23/2022]
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Abstract
This review focuses on biologically active entities from invertebrate sources, especially snails. The reader will encounter several categories of compounds from snails including glycosaminoglycans, peptides, proteins (glycoproteins), and enzymes which possess diverse biological activities. Among glycosaminoglycans, acharan sulfate which was isolated from a giant African snail Acahtina fulica is reviewed extensively. Conotoxins which are also called conopeptides are unique peptide mixtures from marine cone snail. Conotoxins are secreted to capture its prey, and currently have the potential to be highly effective drug candidates. One of the conotoxins is now in the market as a pain killer. Proteins as well as glycoproteins in the snail are known to be involved in the host defense process from an attack of diverse pathogens. Carbohydrate-degrading enzymes characterized and purified in snails are introduced to give an insight into the applicability in glycobiology research such as synthesis and structure characterization of glycoconjugates. It seems that simple snails produce very complicated biological compounds which could be an invaluable source in future therapeutics as well as research areas in natural medicine.
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Affiliation(s)
- Youmie Park
- College of Pharmacy, Inje University, 607 Obang-dong, Gimhae, Gyeongnam 621-749, Republic of Korea
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Dhawan S, Kaur J. Microbial Mannanases: An Overview of Production and Applications. Crit Rev Biotechnol 2008; 27:197-216. [DOI: 10.1080/07388550701775919] [Citation(s) in RCA: 245] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Ootsuka S, Saga N, Suzuki KI, Inoue A, Ojima T. Isolation and cloning of an endo-β-1,4-mannanase from Pacific abalone Haliotis discus hannai. J Biotechnol 2006; 125:269-80. [PMID: 16621092 DOI: 10.1016/j.jbiotec.2006.03.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Revised: 02/09/2006] [Accepted: 03/03/2006] [Indexed: 10/24/2022]
Abstract
An endo-beta-1,4-mannanase was isolated from digestive fluid of Pacific abalone, Haliotis discus hannai, by successive chromatographies on TOYPEARL CM-650M, hydroxyapatite, and TOYOPEARL HW50F. The abalone mannanase, named HdMan in the present paper, showed a molecular mass of approximately 39,000 Da on SDS-PAGE, and exhibited high hydrolyic activity on both galactomannan from locust bean gum and glucomannan from konjac at an optimal pH and temperature of 7.5 and 45 degrees C, respectively. HdMan could degrade either beta-1,4-mannan or beta-1,4-mannooligosaccharides to mannotriose and mannobiose similarly to beta-1,4-mannanases from Pomacea, Littorina, and Mytilus. In addition, HdMan could disperse the fronds of a red alga Porphyra yezoensis into cell masses consisting of 10-20 cells that are available for cell engineering of this alga. cDNAs encoding HdMan were amplified by polymerase chain reaction from an abalone-hepatopancreas cDNA library. From the nucleotide sequences of the cDNAs, the sequence of 1232 bp in total was determined and the amino-acid sequence of 377 residues was deduced from the translational region of 1134 bp locating at nucleotide positions 15-1148. The N-terminal region of 17 residues except for the initiation Met, was regarded as the signal peptide of HdMan because it was absent in the HdMan protein and showed high similarity to the consensus sequence for signal peptides of eukaryote secretory proteins. Accordingly, mature HdMan was considered to consist of 359 residues with the calculated molecular mass of 39,627.2 Da. HdMan is classified into glycoside hydrolase family 5 (GHF5) on the basis of sequence homology to GHF5 enzymes.
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Affiliation(s)
- Shuuji Ootsuka
- Laboratory of Breeding Sciences, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
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Charrier M, Brune A. The gut microenvironment of helicid snails (Gastropoda: Pulmonata): in-situ profiles of pH, oxygen, and hydrogen determined by microsensors. CAN J ZOOL 2003. [DOI: 10.1139/z03-071] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In-situ profiles of pH, oxygen, and hydrogen were measured in isolated guts of starved terrestrial gastropods belonging to four species, Cornu aspersum (syn. Helix aspersa), Elona quimperiana, Helix pomatia, and Helix lucorum (excepted pH), using Clark-type oxygen and hydrogen microsensors and liquid-ion-exchanger pH microelectrodes. The pH profiles in the two phyllophagous species, H. pomatia and C. aspersum, increased by 0.9 and 1.4 from the crop to the distal intestine (pH 6.4 and 7.4, respectively). In the saprophagous E. quimperiana, as in H. pomatia, the pH along the gut axis remained acidic (5.16.6), suggesting saprophagous habits in the latter. In all four species, no oxygen was detected in the gut lumen. Nevertheless, steep oxygen gradients around the gut epithelium indicated high oxygen-uptake rates. The estimated respiratory activity of the intestine ranged between 6.5 (E. quimperiana) and 13.1 (H. lucorum) μmol O2·g fresh mass1·h1. Hydrogen accumulated in the intestine and digestive gland of all snails tested, with the highest values in E. quimperiana and H. pomatia (58 and 78 μM, respectively). These results provide the basis for a better understanding of the microbial and biochemical processes involved in digestion.
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