Displaying publications 1 - 20 of 21 in total

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  1. Nawawi WMFW, Lee KY, Kontturi E, Bismarck A, Mautner A
    Int J Biol Macromol, 2020 Apr 01;148:677-687.
    PMID: 31954796 DOI: 10.1016/j.ijbiomac.2020.01.141
    The structural component of fungal cell walls comprises of chitin covalently bonded to glucan; this constitutes a native composite material (chitin-glucan, CG) combining the strength of chitin and the toughness of glucan. It has a native nano-fibrous structure in contrast to nanocellulose, for which further nanofibrillation is required. Nanopapers can be manufactured from fungal chitin nanofibrils (FChNFs). FChNF nanopapers are potentially applicable in packaging films, composites, or membranes for water treatment due to their distinct surface properties inherited from the composition of chitin and glucan. Here, chitin-glucan nanofibrils were extracted from common mushroom (Agaricus bisporus) cell walls utilizing a mild isolation procedure to preserve the native quality of the chitin-glucan complex. These extracts were readily disintegrated into nanofibre dimensions by a low-energy mechanical blending, thus making the extract dispersion directly suitable for nanopaper preparation using a simple vacuum filtration process. Chitin-glucan nanopaper morphology, mechanical, chemical, and surface properties were studied and compared to chitin nanopapers of crustacean (Cancer pagurus) origin. It was found that fungal extract nanopapers had distinct physico-chemical surface properties, being more hydrophobic than crustacean chitin.
    Matched MeSH terms: Cell Wall/chemistry
  2. Lee HV, Hamid SB, Zain SK
    ScientificWorldJournal, 2014;2014:631013.
    PMID: 25247208 DOI: 10.1155/2014/631013
    Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate's application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.
    Matched MeSH terms: Cell Wall/chemistry
  3. Lim CS, Tung CH, Rosli R, Chong PP
    J Microbiol Methods, 2008 Dec;75(3):576-8.
    PMID: 18727938 DOI: 10.1016/j.mimet.2008.07.026
    This report describes a modified, cost-effective method of cell wall disruption for the yeast Candida spp., which employs the use of glass beads in a simple sorbitol lysis buffer. This method can be used in conjunction with a commercial RNA or genomic DNA isolation method to obtain high-quality RNA or DNA.
    Matched MeSH terms: Cell Wall/chemistry*
  4. Wahidin S, Idris A, Shaleh SR
    Bioresour Technol, 2016 Apr;206:150-4.
    PMID: 26851899 DOI: 10.1016/j.biortech.2016.01.084
    The wet biomass microalgae of Nannochloropsis sp. was converted to biodiesel using direct transesterification (DT) by microwave technique and ionic liquid (IL) as the green solvent. Three different ionic liquids; 1-butyl-3-metyhlimidazolium chloride ([BMIM][Cl], 1-ethyl-3-methylimmidazolium methyl sulphate [EMIM][MeSO4] and 1-butyl-3-methylimidazolium trifluoromethane sulfonate [BMIM][CF3SO3]) and organic solvents (hexane and methanol) were used as co-solvents under microwave irradiation and their performances in terms of percentage disruption, cell walls ruptured and biodiesel yields were compared at different reaction times (5, 10 and 15 min). [EMIM][MeSO4] showed highest percentage cell disruption (99.73%) and biodiesel yield (36.79% per dried biomass) after 15 min of simultaneous reaction. The results demonstrated that simultaneous extraction-transesterification using ILs and microwave irradiation is a potential alternative method for biodiesel production.
    Matched MeSH terms: Cell Wall/chemistry
  5. Teo HL, Wahab RA
    Int J Biol Macromol, 2020 Oct 15;161:1414-1430.
    PMID: 32791266 DOI: 10.1016/j.ijbiomac.2020.08.076
    There is an array of methodologies to prepare nanocellulose (NC) and its fibrillated form (CNF) with enhanced physicochemical characteristics. However, acids, bases or organosolv treatments on biomass are far from green, and seriously threaten the environment. Current approach to produce NC/CNF from biomass should be revised and embrace the concept of sustainability and green chemistry. Although hydrothermal process, high-pressure homogenization, ball milling technique, deep eutectic solvent treatment, enzymatic hydrolysis etc., are the current techniques for producing NC, the route designs remain imperfect. Herein, this review highlights the latest methodologies in the pre-processing and isolating of NC/CNF from lignocellulose biomass, by largely focusing on related papers published in the past two years till date. This article also explores the latest advancements in environmentally friendly NC extraction techniques that cooperatively use ball milling and enzymatic hydrolytic routes as an eco-efficient way to produce NC/CNF, alongside the potential applications of the nano-sized celluloses.
    Matched MeSH terms: Cell Wall/chemistry
  6. Tan MS, Rahman S, Dykes GA
    Appl Environ Microbiol, 2016 01 15;82(2):680-8.
    PMID: 26567310 DOI: 10.1128/AEM.02609-15
    Minimally processed fresh produce has been implicated as a major source of foodborne microbial pathogens globally. These pathogens must attach to the produce in order to be transmitted. Cut surfaces of produce that expose cell walls are particularly vulnerable. Little is known about the roles that different structural components (cellulose, pectin, and xyloglucan) of plant cell walls play in the attachment of foodborne bacterial pathogens. Using bacterial cellulose-derived plant cell wall models, we showed that the presence of pectin alone or xyloglucan alone affected the attachment of three Salmonella enterica strains (Salmonella enterica subsp. enterica serovar Enteritidis ATCC 13076, Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028, and Salmonella enterica subsp. indica M4) and Listeria monocytogenes ATCC 7644. In addition, we showed that this effect was modulated in the presence of both polysaccharides. Assays using pairwise combinations of S. Typhimurium ATCC 14028 and L. monocytogenes ATCC 7644 showed that bacterial attachment to all plant cell wall models was dependent on the characteristics of the individual bacterial strains and was not directly proportional to the initial concentration of the bacterial inoculum. This work showed that bacterial attachment was not determined directly by the plant cell wall model or bacterial physicochemical properties. We suggest that attachment of the Salmonella strains may be influenced by the effects of these polysaccharides on physical and structural properties of the plant cell wall model. Our findings improve the understanding of how Salmonella enterica and Listeria monocytogenes attach to plant cell walls, which may facilitate the development of better ways to prevent the attachment of these pathogens to such surfaces.
    Matched MeSH terms: Cell Wall/chemistry
  7. Lee PY, Gam LH, Yong VC, Rosli R, Ng KP, Chong PP
    J Appl Microbiol, 2014 Sep;117(3):854-65.
    PMID: 24909754 DOI: 10.1111/jam.12562
    This study was conducted to identify antigenic proteins of Candida tropicalis that are targeted by the host immune system.
    Matched MeSH terms: Cell Wall/chemistry
  8. Lee LH, Zainal N, Azman AS, Mutalib NA, Hong K, Chan KG
    Int J Syst Evol Microbiol, 2014 May;64(Pt 5):1461-1467.
    PMID: 24449791 DOI: 10.1099/ijs.0.058701-0
    A novel actinobacterial strain, designated MUSC 201T, was isolated from a mangrove soil collected from Kuantan, the capital city of Pahang State in Malaysia. The taxonomic status of this strain was determined using a polyphasic approach. Comparative 16S rRNA gene sequence analysis revealed that strain MUSC 201T represented a novel lineage within the class Actinobacteria. Strain MUSC 201T formed a distinct clade in the family Nocardioidaceae and was most closely related to the members of the genera Nocardioides (16S rRNA gene sequence similarity, 91.9-95.1%), Aeromicrobium (92.7-94.6%), Marmoricola (92.5-93.1%) and Kribbella (91.5-92.4%). The cells of this strain were irregular coccoid to short rod shaped. The peptidoglycan contained ll-diaminopimelic acid as diagnostic diamino acid and the peptidoglycan type was A3γ. The peptidoglycan cell wall contained ll-diaminopimelic acid, glycine, glutamic acid and alanine in a molar ratio of 1.5:0.9:1.0:1.5. The cell-wall sugars were galactose and rhamnose. The predominant menaquinone was MK-9(H4). The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphoglycolipid, glycolipid and four unknown phospholipids. The major cellular fatty acids were C18:1ω9c (30.8%), C16:0 (24.1%), and 10-methyl C18:0 (13.9%). The DNA G+C content was 72.0±0.1 mol%. On the basis of phylogenetic and phenotypic differences from members of the genera of the family Nocardioidaceae, a novel genus and species, Mumia flava gen. nov., sp. nov. are proposed. The type strain of Mumia flava is MUSC 201T (=DSM 27763T=MCCC 1A00646T=NBRC 109973T).
    Matched MeSH terms: Cell Wall/chemistry
  9. Tan MS, Wang Y, Dykes GA
    Foodborne Pathog Dis, 2013 Nov;10(11):992-4.
    PMID: 23941519 DOI: 10.1089/fpd.2013.1536
    This study aimed to establish, as a proof of concept, whether bacterial cellulose (BC)-derived plant cell wall models could be used to investigate foodborne bacterial pathogen attachment. Attachment of two strains each of Salmonella enterica and Listeria monocytogenes to four BC-derived plant cell wall models (namely, BC, BC-pectin [BCP], BC-xyloglucan [BCX], and BC-pectin-xyloglucan [BCPX]) was investigated. Chemical analysis indicated that the BCPX composite (31% cellulose, 45.6% pectin, 23.4% xyloglucan) had a composition typical of plant cell walls. The Salmonella strains attached in significantly (p<0.05) higher numbers (~6 log colony-forming units [CFU]/cm(2)) to the composites than the Listeria strains (~5 log CFU/cm(2)). Strain-specific differences were also apparent with one Salmonella strain, for example, attaching in significantly (p<0.05) higher numbers to the BCX composite than to the other composites. This study highlights the potential usefulness of these composites to understand attachment of foodborne bacteria to fresh produce.
    Matched MeSH terms: Cell Wall/chemistry*
  10. Nayan N, van Erven G, Kabel MA, Sonnenberg AS, Hendriks WH, Cone JW
    J Sci Food Agric, 2019 Jun;99(8):4054-4062.
    PMID: 30737799 DOI: 10.1002/jsfa.9634
    BACKGROUND: White rot fungi have been used to improve the nutritive value of lignocellulose for ruminants. In feed analysis, the Van Soest method is widely used to determine the cell wall contents. To assess the reliability of this method (Method A) for determination of cell wall contents in fungal-treated wheat straw, we compared a combined monosaccharide analysis and pyrolysis coupled to gas chromatography with mass spectrometry (Py-GC/MS) (Method B). Ruminal digestibility, measured as in vitro gas production (IVGP), was subsequently used to examine which method explains best the effect of fungal pretreatment on the digestibility of wheat straw.

    RESULTS: Both methods differed considerably in the mass recoveries of the individual cell wall components, which changed on how we assess their degradation characteristics. For example, Method B gave a higher degradation of lignin (61.9%), as compared to Method A (33.2%). Method A, however, showed a better correlation of IVGP with the ratio of lignin to total structural carbohydrates, as compared to Method B (Pearson's r of -0.84 versus -0.69). Nevertheless, Method B provides a more accurate quantification of lignin, reflecting its actual modification and degradation. With the information on the lignin structural features, Method B presents a substantial advantage in understanding the underlying mechanisms of lignin breakdown. Both methods, however, could not accurately quantify the cellulose contents - among others, due to interference of fungal biomass.

    CONCLUSION: Method A only accounts for the recalcitrant residue and therefore is more suitable for evaluating ruminal digestibility. Method B allows a more accurate quantification of cell wall, required to understand and better explains the actual modification of the cell wall. The suitability of both methods, therefore, depends on their intended purposes. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

    Matched MeSH terms: Cell Wall/chemistry*
  11. Strout G, Russell SD, Pulsifer DP, Erten S, Lakhtakia A, Lee DW
    Ann Bot, 2013 Oct;112(6):1141-8.
    PMID: 23960046 DOI: 10.1093/aob/mct172
    BACKGROUND AND AIMS: Blue-green iridescence in the tropical rainforest understorey sedge Mapania caudata creates structural coloration in its leaves through a novel photonic mechanism. Known structures in plants producing iridescent blues consist of altered cellulose layering within cell walls and in special bodies, and thylakoid membranes in specialized plastids. This study was undertaken in order to determine the origin of leaf iridescence in this plant with particular attention to nano-scale components contributing to this coloration.

    METHODS: Adaxial walls of leaf epidermal cells were characterized using high-pressure-frozen freeze-substituted specimens, which retain their native dimensions during observations using transmission and scanning microscopy, accompanied by energy-dispersive X-ray spectroscopy to identify the role of biogenic silica in wall-based iridescence. Biogenic silica was experimentally removed using aqueous Na2CO3 and optical properties were compared using spectral reflectance.

    KEY RESULTS AND CONCLUSIONS: Blue iridescence is produced in the adaxial epidermal cell wall, which contains helicoid lamellae. The blue iridescence from cell surfaces is left-circularly polarized. The position of the silica granules is entrained by the helicoid microfibrillar layers, and granules accumulate at a uniform position within the helicoids, contributing to the structure that produces the blue iridescence, as part of the unit cell responsible for 2 ° Bragg scatter. Removal of silica from the walls eliminated the blue colour. Addition of silica nanoparticles on existing cellulosic lamellae is a novel mechanism for adding structural colour in organisms.

    Matched MeSH terms: Cell Wall/chemistry
  12. Chen X, Li QY, Li GD, Xu FJ, Jiang Y, Han L, et al.
    Antonie Van Leeuwenhoek, 2016 Sep;109(9):1177-83.
    PMID: 27260265 DOI: 10.1007/s10482-016-0718-1
    A novel aerobic, non-motile, Gram-positive, rod-shaped actinobacterium, designated YIM 100951(T), was isolated from the faeces of civets (Viverra zibetha) living in the National Nature Protect Region in Selangor, Malaysia. Strain YIM 100951(T) shows high similarities with Microbacterium barkeri DSM 20145(T) (97.6 %), Microbacterium oryzae MB10(T) (97.3 %), Microbacterium lemovicicum ViU22(T) (97.1 %) and Microbacterium indicum BBH6(T) (97.0 %) based on their 16S rRNA genes. However, phylogenetic analysis showed that strain YIM 100951(T) formed a clade with Microbacterium halotolerans YIM 70130(T) (96.7 %), Microbacterium populi 10-107-8(T) (96.7 %) and Microbacterium sediminis YLB-01(T) (96.9 %). DNA-DNA hybridization was carried out between strains YIM 100951(T) and M. barkeri DSM 20145(T), the result showed a value of 23.2 ± 4.5 %. In addition, some of the physiological, biochemical and chemotaxonomic characteristics of strain YIM 100951(T) are different from the closely related strains. Thus, we suggest that strain YIM 100951(T) represents a novel species of the genus Microbacterium, for which the name Microbacterium gilvum sp. nov. is proposed. The type strain is YIM 100951(T) (=DSM 26235(T) = CCTCC AB 2012971(T)).
    Matched MeSH terms: Cell Wall/chemistry
  13. Lee LH, Azman AS, Zainal N, Yin WF, Mutalib NA, Chan KG
    Int J Syst Evol Microbiol, 2015 Mar;65(Pt 3):996-1002.
    PMID: 25563924 DOI: 10.1099/ijs.0.000053
    Strain MUSC 117(T) was isolated from mangrove soil of the Tanjung Lumpur forest in Pahang, Malaysia. This bacterium was yellowish-white pigmented, Gram-staining-positive, rod-coccus shaped and non-motile. On the basis of 16S rRNA gene sequence, strain MUSC 117(T) exhibited highest sequence similarity to Sinomonas atrocyanea DSM 20127(T) (98.0 %), Sinomonas albida LC13(T) (97.9 %) and Sinomonas soli CW 59(T) (97.8 %), and lower (<97.6 %) sequence similarity to other species of the genus Sinomonas. DNA-DNA hybridization experiments revealed a low level of DNA-DNA relatedness (less than 27 %) between strain MUSC 117(T) and closely related species. Chemotaxonomically, the peptidoglycan type was A3α, containing the amino acids lysine, serine, glycine, alanine, glutamic acid and muramic acid. The whole-cell sugars detected were rhamnose, ribose, glucose, galactose and a smaller amount of mannose. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and five unidentified glycolipids. The major fatty acids (>10.0 %) of the cell membrane were anteiso-C15 : 0 (39.4 %), C18 : 1ω7c (17.7 %), anteiso-C17 : 0 (17.2 %) and iso-C16 : 0 (11.4 %). The predominant respiratory quinones detected were MK-9(H2) and MK-9. The DNA G+C content was 67.3 mol%. A comparison of BOX-PCR fingerprints indicated that strain MUSC 117(T) represented a unique DNA profile. Results based on a polyphasic approach showed that strain MUSC 117(T) represents a novel species of the genus Sinomonas, for which the name Sinomonas humi sp. nov. is proposed. The type strain of Sinomonas humi sp. nov. is MUSC 117(T) ( = DSM 29362(T) = MCCC 1K00410(T) = NBRC 110653(T)).
    Matched MeSH terms: Cell Wall/chemistry
  14. Lee LH, Cheah YK, Sidik SM, Xie QY, Tang YL, Lin HP, et al.
    Int J Syst Evol Microbiol, 2013 Jan;63(Pt 1):241-248.
    PMID: 22389286 DOI: 10.1099/ijs.0.038232-0
    Three novel actinobacteria, strains 39(T), 40 and 41, were isolated from soil collected from Barrientos Island in the Antarctic. The taxonomic status of these strains was determined using a polyphasic approach. Comparison of 16S rRNA gene sequences revealed that strain 39(T) represented a novel lineage within the family Dermacoccaceae and was most closely related to members of the genera Demetria (96.9 % 16S rRNA gene sequence similarity), Branchiibius (95.7 %), Dermacoccus (94.4-95.3 %), Calidifontibacter (94.6 %), Luteipulveratus (94.3 %), Yimella (94.2 %) and Kytococcus (93.1 %). Cells were irregular cocci and short rods. The peptidoglycan type was A4α with an L-Lys-L-Ser-D-Asp interpeptide bridge. The cell-wall sugars were galactose and glucose. The major menaquinone was MK-8(H(4)). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphoglycolipid, two glycolipids and one unknown phospholipid. The acyl type of the cell-wall polysaccharide was N-acetyl. The major cellular fatty acids were anteiso-C(17 : 0) (41.97 %), anteiso-C(17 : 1)ω9c (32.16 %) and iso-C(16 : 0) (7.68 %). The DNA G+C content of strain 39(T) was 68.4 mol%. On the basis of phylogenetic and phenotypic differences from other genera of the family Dermacoccaceae, a novel genus and species, Barrientosiimonas humi gen. nov., sp. nov., is proposed; the type strain of the type species is 39(T) (=CGMCC 4.6864(T) = DSM 24617(T)).
    Matched MeSH terms: Cell Wall/chemistry
  15. Juboi H, Basik AA, Shamsul SSG, Arnold P, Schmitt EK, Sanglier JJ, et al.
    Int J Syst Evol Microbiol, 2015 Nov;65(11):4113-4120.
    PMID: 26303235 DOI: 10.1099/ijsem.0.000548
    The taxonomic position of an actinobacterium strain, C296001T, isolated from a soil sample collected in Sarawak, Malaysia, was established using a polyphasic approach. Phylogenetically, strain C296001T was closely associated with the genus Luteipulveratus and formed a distinct monophyletic clade with the only described species, Luteipulveratus mongoliensis NBRC 105296T. The 16S rRNA gene sequence similarity between strain C296001T and L. mongoliensis was 98.7 %. DNA-DNA hybridization results showed that the relatedness of strain C296001T to L. mongoliensis was only 21.5 %. The DNA G+C content of strain C296001T was 71.7 mol%. Using a PacBio RS II system, whole genome sequences for strains C296001T and NBRC 105296T were obtained. The genome sizes of 4.5 Mbp and 5.4 Mbp determined were similar to those of other members of the family Dermacoccaceae. The cell-wall peptidoglycan contained lysine, alanine, aspartic acid, glutamic acid and serine, representing the peptidoglycan type A4α l-Lys-l-Ser-d-Asp. The major menaquinones were MK-8(H4), MK-8 and MK-8(H2). Phosphatidylglycerol, phosphatidylinositol, diphosphatidylglycerol and phosphoglycolipid were the polar lipids, while the whole-cell sugars were glucose, fucose and lesser amounts of ribose and galactose. The major fatty acids were iso-C16 : 0, anteiso-C17 : 0, iso-C16 : 1 H, anteiso-C17 : 1ω9c, iso-C18 : 0 and 10-methyl C17 : 0. Chemotaxonomic analyses showed that C296001T had typical characteristics of members of the genus Luteipulveratus, with the main differences occurring in phenotypic characteristics. On the basis of the phenotypic and chemotaxonomic evidence, it is proposed that strain C296001T be classified as a representative of a novel species in the genus Luteipulveratus, for which the name Luteipulveratus halotolerans sp. nov. is recommended. The type strain is C296001T ( = ATCC TSD-4T = JCM 30660T).
    Matched MeSH terms: Cell Wall/chemistry
  16. Tan MS, Moore SC, Tabor RF, Fegan N, Rahman S, Dykes GA
    BMC Microbiol, 2016 09 15;16:212.
    PMID: 27629769 DOI: 10.1186/s12866-016-0832-2
    BACKGROUND: Processing of fresh produce exposes cut surfaces of plant cell walls that then become vulnerable to human foodborne pathogen attachment and contamination, particularly by Salmonella enterica. Plant cell walls are mainly composed of the polysaccharides cellulose, pectin and hemicelluloses (predominantly xyloglucan). Our previous work used bacterial cellulose-based plant cell wall models to study the interaction between Salmonella and the various plant cell wall components. We demonstrated that Salmonella attachment was favoured in the presence of pectin while xyloglucan had no effect on its attachment. Xyloglucan significantly increased the attachment of Salmonella cells to the plant cell wall model only when it was in association with pectin. In this study, we investigate whether the plant cell wall polysaccharides mediate Salmonella attachment to the bacterial cellulose-based plant cell wall models through specific carbohydrate interactions or through the effects of carbohydrates on the physical characteristics of the attachment surface.

    RESULTS: We found that none of the monosaccharides that make up the plant cell wall polysaccharides specifically inhibit Salmonella attachment to the bacterial cellulose-based plant cell wall models. Confocal laser scanning microscopy showed that Salmonella cells can penetrate and attach within the tightly arranged bacterial cellulose network. Analysis of images obtained from atomic force microscopy revealed that the bacterial cellulose-pectin-xyloglucan composite with 0.3 % (w/v) xyloglucan, previously shown to have the highest number of Salmonella cells attached to it, had significantly thicker cellulose fibrils compared to other composites. Scanning electron microscopy images also showed that the bacterial cellulose and bacterial cellulose-xyloglucan composites were more porous when compared to the other composites containing pectin.

    CONCLUSIONS: Our study found that the attachment of Salmonella cells to cut plant cell walls was not mediated by specific carbohydrate interactions. This suggests that the attachment of Salmonella strains to the plant cell wall models were more dependent on the structural characteristics of the attachment surface. Pectin reduces the porosity and space between cellulose fibrils, which then forms a matrix that is able to retain Salmonella cells within the bacterial cellulose network. When present with pectin, xyloglucan provides a greater surface for Salmonella cells to attach through the thickening of cellulose fibrils.

    Matched MeSH terms: Cell Wall/chemistry
  17. Idris H, Nouioui I, Pathom-Aree W, Castro JF, Bull AT, Andrews BA, et al.
    Antonie Van Leeuwenhoek, 2018 Sep;111(9):1523-1533.
    PMID: 29428970 DOI: 10.1007/s10482-018-1039-3
    The taxonomic position of a novel Amycolatopsis strain isolated from a high altitude Atacama Desert subsurface soil was established using a polyphasic approach. The strain, isolate H5T, was shown to have chemical properties typical of members of the genus Amycolatopsis such as meso-diaminopimelic acid as the diamino acid in the cell wall peptidoglycan, arabinose and galactose as diagnostic sugars and MK-9(H4) as the predominant isoprenologue. It also has cultural and morphological properties consistent with its classification in the genus, notably the formation of branching substrate hyphae which fragment into rod-like elements. 16S rRNA gene sequence analyses showed that the strain is closely related to the type strain of Amycolatopsis mediterranei but could be distinguished from this and other related Amycolatopsis strains using a broad range of phenotypic properties. It was separated readily from the type strain of Amycolatopsis balhymycina, its near phylogenetic neighbour, based on multi-locus sequence data, by low average nucleotide identity (92.9%) and in silico DNA/DNA relatedness values (51.3%) calculated from draft genome assemblies. Consequently, the strain is considered to represent a novel species of Amycolatopsis for which the name Amycolatopsis vastitatis sp. nov. is proposed. The type strain is H5T (= NCIMB 14970T = NRRL B-65279T).
    Matched MeSH terms: Cell Wall/chemistry
  18. Wang D, Samsulrizal NH, Yan C, Allcock NS, Craigon J, Blanco-Ulate B, et al.
    Plant Physiol, 2019 02;179(2):544-557.
    PMID: 30459263 DOI: 10.1104/pp.18.01187
    Tomato (Solanum lycopersicum) is a globally important crop with an economic value in the tens of billions of dollars, and a significant supplier of essential vitamins, minerals, and phytochemicals in the human diet. Shelf life is a key quality trait related to alterations in cuticle properties and remodeling of the fruit cell walls. Studies with transgenic tomato plants undertaken over the last 20 years have indicated that a range of pectin-degrading enzymes are involved in cell wall remodeling. These studies usually involved silencing of only a single gene and it has proved difficult to compare the effects of silencing these genes across the different experimental systems. Here we report the generation of CRISPR-based mutants in the ripening-related genes encoding the pectin-degrading enzymes pectate lyase (PL), polygalacturonase 2a (PG2a), and β-galactanase (TBG4). Comparison of the physiochemical properties of the fruits from a range of PL, PG2a, and TBG4 CRISPR lines demonstrated that only mutations in PL resulted in firmer fruits, although mutations in PG2a and TBG4 influenced fruit color and weight. Pectin localization, distribution, and solubility in the pericarp cells of the CRISPR mutant fruits were investigated using the monoclonal antibody probes LM19 to deesterified homogalacturonan, INRA-RU1 to rhamnogalacturonan I, LM5 to β-1,4-galactan, and LM6 to arabinan epitopes, respectively. The data indicate that PL, PG2a, and TBG4 act on separate cell wall domains and the importance of cellulose microfibril-associated pectin is reflected in its increased occurrence in the different mutant lines.
    Matched MeSH terms: Cell Wall/chemistry
  19. Noor YM, Samsulrizal NH, Jema'on NA, Low KO, Ramli AN, Alias NI, et al.
    Gene, 2014 Jul 25;545(2):253-61.
    PMID: 24811681 DOI: 10.1016/j.gene.2014.05.012
    Bacillus lehensis G1 is a Gram-positive, moderately alkalitolerant bacterium isolated from soil samples. B. lehensis produces cyclodextrin glucanotransferase (CGTase), an enzyme that has enabled the extensive use of cyclodextrin in foodstuffs, chemicals, and pharmaceuticals. The genome sequence of B. lehensis G1 consists of a single circular 3.99 Mb chromosome containing 4017 protein-coding sequences (CDSs), of which 2818 (70.15%) have assigned biological roles, 936 (23.30%) have conserved domains with unknown functions, and 263 (6.55%) have no match with any protein database. Bacillus clausii KSM-K16 was established as the closest relative to B. lehensis G1 based on gene content similarity and 16S rRNA phylogenetic analysis. A total of 2820 proteins from B. lehensis G1 were found to have orthologues in B. clausii, including sodium-proton antiporters, transport proteins, and proteins involved in ATP synthesis. A comparative analysis of these proteins and those in B. clausii and other alkaliphilic Bacillus species was carried out to investigate their contributions towards the alkalitolerance of the microorganism. The similarities and differences in alkalitolerance-related genes among alkalitolerant/alkaliphilic Bacillus species highlight the complex mechanism of pH homeostasis. The B. lehensis G1 genome was also mined for proteins and enzymes with potential viability for industrial and commercial purposes.
    Matched MeSH terms: Cell Wall/chemistry
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