Unraveling the xylanolytic potential of Acidobacteria bacterium AB60 from Cerrado soils

2020 ◽  
Vol 367 (18) ◽  
Author(s):  
Gisele Regina Rodrigues ◽  
Otávio Henrique Bezerra Pinto ◽  
Luís Felipe Schroeder ◽  
Gabriel da Rocha Fernandes ◽  
Ohana Yonara Assis Costa ◽  
...  
Keyword(s):  
Carboxymethyl Cellulose ◽  
Plant Cell Wall ◽  
Genomic Library ◽  
Cellulose Degradation ◽  
Open Reading Frames ◽  
Wall Material ◽  
Rrna Gene ◽  
Functional Screening ◽  
Glycosyl Hydrolases ◽  
Xylan Degradation

ABSTRACT The presence of genes for glycosyl hydrolases in many Acidobacteria genomes indicates an important role in the degradation of plant cell wall material. Acidobacteria bacterium AB60 was obtained from Cerrado oligotrophic soil in Brazil, where this phylum is abundant. The 16S rRNA gene analyses showed that AB60 was closely related to the genera Occallatibacter and Telmatobacter. However, AB60 grew on xylan as carbon source, which was not observed in Occallatibacter species; but growth was not detected on medium containing carboxymethyl cellulose, as observed in Telmatobacter. Nevertheless, the genome analysis of AB60 revealed genes for the enzymes involved in cellulose as well as xylan degradation. In addition to enzymes involved in xylan degradation, α-l-rhamnosidase was detected in the cultures of AB60. Functional screening of a small-insert genomic library did not identify any clones capable of carboxymethyl cellulose degradation, but open reading frames coding α-l-arabinofuranosidase and α-l-rhamnosidase were present in clones showing xylan degradation halos. Both enzymes act on the lateral chains of heteropolymers such as pectin and some hemicelluloses. These results indicate that the hydrolysis of α-linked sugars may offer a metabolic niche for slow-growing Acidobacteria, allowing them to co-exist with other plant-degrading microbes that hydrolyze β-linked sugars from cellulose or hemicellulose backbones.

scholarly journals Novel Family of Carbohydrate-Binding Modules Revealed by the Genome Sequence of Spirochaeta thermophila DSM 6192

2011 ◽  
Vol 77 (15) ◽  
pp. 5483-5489 ◽  
Author(s):  
Angel Angelov ◽  
Christoph Loderer ◽  
Susanne Pompei ◽  
Wolfgang Liebl
Keyword(s):  
Genome Sequence ◽  
Sequence Data ◽  
Cellulose Degradation ◽  
Sequence Similarity ◽  
Open Reading Frames ◽  
Carbohydrate Binding ◽  
Functional Screening ◽  
Content Type ◽  
C Terminus ◽  
Carbohydrate Binding Modules

ABSTRACTSpirochaeta thermophilais a thermophilic, free-living, and cellulolytic anaerobe. The genome sequence data for this organism have revealed a high density of genes encoding enzymes from more than 30 glycoside hydrolase (GH) families and a noncellulosomal enzyme system for (hemi)cellulose degradation. Functional screening of a fosmid library whose inserts were mapped on theS. thermophilagenome sequence allowed the functional annotation of numerous GH open reading frames (ORFs). Seven different GH ORFs from theS. thermophilaDSM 6192 genome, all putative β-glycanase ORFs according to sequence similarity analysis, contained a highly conserved novel GH-associated module of unknown function at their C terminus. Four of these GH enzymes were experimentally verified as xylanase, β-glucanase, β-glucanase/carboxymethylcellulase (CMCase), and CMCase. Binding experiments performed with the recombinantly expressed and purified GH-associated module showed that it represents a new carbohydrate-binding module (CBM) that binds to microcrystalline cellulose and is highly specific for this substrate. In the course of this work, the new CBM type was only detected inSpirochaeta, but recently we found sequences with detectable similarity to the module in the draft genomes ofCytophaga fermentansandMahella australiensis, both of which are phylogenetically very distant fromS. thermophilaand noncellulolytic, yet inhabit similar environments. This suggests a possibly broad distribution of the module in nature.

scholarly journals Characterization of Two Noncellulosomal Subunits, ArfA and BgaA, from Clostridium cellulovorans That Cooperate with the Cellulosome in Plant Cell Wall Degradation

2002 ◽  
Vol 184 (24) ◽  
pp. 6859-6865 ◽  
Author(s):  
Akihiko Kosugi ◽  
Koichiro Murashima ◽  
Roy H. Doi
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Genomic Library ◽  
Amino Acid Sequences ◽  
Glycosyl Hydrolases ◽  
Cell Wall Degradation ◽  
Clostridium Cellulovorans ◽  
Molecular Weights ◽  
Plant Cell Wall Degradation

ABSTRACT Plant cell wall degradation by Clostridium cellulovorans requires the cooperative activity of its cellulases and hemicellulases. To characterize the α-l-arabinosidases that are involved in hemicellulose degradation, we screened the C. cellulovorans genomic library for clones with α-l-arabinofuranosidase or α-l-arabinopyranosidase activity, and two clones utilizing different substrates were isolated. The genes from the two clones, arfA and bgaA, encoded proteins of 493 and 659 amino acids with molecular weights of 55,731 and 76,414, respectively, and were located on neighboring loci. The amino acid sequences for ArfA and BgaA were related to α-l-arabinofuranosidase and β-galactosidase, respectively, which are classified as family 51 and family 42 glycosyl hydrolases, respectively. Recombinant ArfA (rArfA) had high activity for p-nitrophenyl α-l-arabinofuranoside, arabinoxylan, and arabinan but not for p-nitrophenyl α-l-arabinopyranoside. On the other hand, recombinant BgaA (rBgaA) hydrolyzed not only p-nitrophenyl α-l-arabinopyranoside but also p-nitrophenyl β-d-galactopyranoside. However, when the affinities of rBgaA for p-nitrophenyl α-l-arabinopyranoside and p-nitrophenyl β-d-galactopyranoside were compared, the Km values were 1.51 and 6.06 mM, respectively, suggesting that BgaA possessed higher affinity for α-l-arabinopyranose residues than for β-d-galactopyranoside residues and possessed a novel enzymatic property for a family 42 β-galactosidase. Activity staining analyses revealed that ArfA and BgaA were located exclusively in the noncellulosomal fraction. When rArfA and rBgaA were incubated with β-1,4-xylanase A (XynA), a cellulosomal enzyme from C. cellulovorans, on plant cell wall polymers, the plant cell wall-degrading activity was synergistically increased compared with that observed with XynA alone. These results indicate that, to obtain effective plant cell wall degradation, there is synergy between noncellulosomal and cellulosomal subunits.

scholarly journals Functional Genomic Identification of Cadmium Resistance Genes from a High GC Clone Library by Coupling the Sanger and PacBio Sequencing Strategies

Genes ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 7
Author(s):  
Jinghao Chen ◽  
Chao Xing ◽  
Xin Zheng ◽  
Xiaofang Li
Keyword(s):  
High Throughput ◽  
Resistance Genes ◽  
Sanger Sequencing ◽  
Genomic Library ◽  
Full Length ◽  
Host Cells ◽  
Full Genome Sequence ◽  
Functional Screening ◽  
Functional Genomic ◽  
Pacbio Sequencing

Functional (meta) genomics allows the high-throughput identification of functional genes in a premise-free way. However, it is still difficult to perform Sanger sequencing for high GC DNA templates, which hinders the functional genomic exploration of a high GC genomic library. Here, we developed a procedure to resolve this problem by coupling the Sanger and PacBio sequencing strategies. Identification of cadmium (Cd) resistance genes from a small-insert high GC genomic library was performed to test the procedure. The library was generated from a high GC (75.35%) bacterial genome. Nineteen clones that conferred Cd resistance to Escherichia coli subject to Sanger sequencing directly. The positive clones were in parallel subject to in vivo amplification in host cells, from which recombinant plasmids were extracted and linearized by selected restriction endonucleases. PacBio sequencing was performed to obtain the full-length sequences. As the identities, partial sequences from Sanger sequencing were aligned to the full-length sequences from PacBio sequencing, which led to the identification of seven unique full-length sequences. The unique sequences were further aligned to the full genome sequence of the source strain. Functional screening showed that the identified positive clones were all able to improve Cd resistance of the host cells. The functional genomic procedure developed here couples the Sanger and PacBio sequencing methods and overcomes the difficulties in PCR approaches for high GC DNA. The procedure can be a promising option for the high-throughput sequencing of functional genomic libraries, and realize a cost-effective and time-efficient identification of the positive clones, particularly for high GC genetic materials.

scholarly journals Arabinanase A from Pseudomonas fluorescens subsp. cellulosa exhibits both an endo- and an exo- mode of action

1997 ◽  
Vol 323 (2) ◽  
pp. 547-555 ◽  
Author(s):  
Vincent A. McKIE ◽  
Gary W. BLACK ◽  
Sarah J. MILLWARD-SADLER ◽  
Geoffrey P. HAZLEWOOD ◽  
Judith I. LAURIE ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Mode Of Action ◽  
Plant Cell Wall ◽  
Catalytic Domain ◽  
Genomic Library ◽  
Glycosyl Hydrolase ◽  
Single Copy ◽  
Terminal Sequence ◽  
Reading Frame ◽  
Significant Release

Pseudomonas fluorescens subsp. cellulosa expressed arabinanase activity when grown on media supplemented with arabinan or arabinose. Arabinanase activity was not induced by the inclusion of other plant structural polysaccharides, and was repressed by the addition of glucose. The majority of the Pseudomonas arabinanase activity was extracellular. Screening of a genomic library of P. fluorescens subsp. cellulosa DNA constructed in Lambda ZAPII, for recombinants that hydrolysed Red-dyed arabinan, identified five arabinan-degrading plaques. Each of the phage contained the same Pseudomonas arabinanase gene, designated arbA, which was present as a single copy in the Pseudomonas genome. The nucleotide sequence of arbA revealed an open reading frame of 1041 bp encoding a protein, designated arabinanase A (ArbA), of Mr 39438. The N-terminal sequence of ArbA exhibited features typical of a prokaryotic signal peptide. Analysis of the primary structure of ArbA indicated that, unlike most Pseudomonas plant cell wall hydrolases, it did not contain linker sequences or have a modular structure, but consisted of a single catalytic domain. Sequence comparison between the Pseudomonas arabinanase and proteins in the SWISS-PROT database showed that ArbA exhibits greatest sequence identity with arabinanase A from Aspergillus niger, placing the enzyme in glycosyl hydrolase Family 43. The significance of the differing substrate specificities of enzymes in Family 43 is discussed. ArbA purifed from a recombinant strain of Escherichia coli had an Mr of 34000 and an N-terminal sequence identical to residues 32–51 of the deduced sequence of ArbA, and hydrolysed linear arabinan, carboxymethylarabinan and arabino-oligosaccharides. The enzyme displayed no activity against other plant structural polysaccharides, including branched sugar beet arabinan. ArbA produced almost exclusively arabinotriose from linear arabinan and appeared to hydrolyse arabino-oligosaccharides by successively releasing arabinotriose. ArbA and the Aspergillus arabinanase mediated a decrease in the viscosity of linear arabinan that was associated with a significant release of reducing sugar. We propose that ArbA is an arabinanase that exhibits both an endo- and an exo- mode of action.

scholarly journals Conserved Processes and Lineage-Specific Proteins in Fungal Cell Wall Evolution

2007 ◽  
Vol 6 (12) ◽  
pp. 2269-2277 ◽  
Author(s):  
Juan E. Coronado ◽  
Saad Mneimneh ◽  
Susan L. Epstein ◽  
Wei-Gang Qiu ◽  
Peter N. Lipke
Keyword(s):  
Cell Wall ◽  
Protein Function ◽  
Phosphatidyl Inositol ◽  
Low Complexity ◽  
Open Reading Frames ◽  
Specific Cell ◽  
Glycosyl Hydrolases ◽  
Fungal Cell ◽  
Structural Wall ◽  
Lineage Specificity

ABSTRACT The cell wall is a defining organelle that differentiates fungi from its sister clades in the opisthokont superkingdom. With a sensitive technique to align low-complexity protein sequences, we have identified 187 cell wall-related proteins in Saccharomyces cerevisiae and determined the presence or absence of homologs in 17 other fungal genomes. There were both conserved and lineage-specific cell wall proteins, and the degree of conservation was strongly correlated with protein function. Some functional classes were poorly conserved and lineage specific: adhesins, structural wall glycoprotein components, and unannotated open reading frames. These proteins are primarily those that are constituents of the walls themselves. On the other hand, glycosyl hydrolases and transferases, proteases, lipases, proteins in the glycosyl phosphatidyl-inositol-protein synthesis pathway, and chaperones were strongly conserved. Many of these proteins are also conserved in other eukaryotes and are associated with wall synthesis in plants. This gene conservation, along with known similarities in wall architecture, implies that the basic architecture of fungal walls is ancestral to the divergence of the ascomycetes and basidiomycetes. The contrasting lineage specificity of wall resident proteins implies diversification. Therefore, fungal cell walls consist of rapidly diversifying proteins that are assembled by the products of an ancestral and conserved set of genes.

scholarly journals Functional Screening of a Metagenomic Library Reveals Operons Responsible for Enhanced Intestinal Colonization by Gut Commensal Microbes

2013 ◽  
Vol 79 (12) ◽  
pp. 3829-3838 ◽  
Author(s):  
Mi Young Yoon ◽  
Kang-Mu Lee ◽  
Yujin Yoon ◽  
Junhyeok Go ◽  
Yongjin Park ◽  
...  
Keyword(s):  
Bac Library ◽  
Metagenomic Library ◽  
Artificial Chromosome ◽  
Open Reading Frames ◽  
Functional Screening ◽  
Sequence Alignments ◽  
Protein Coding ◽  
Content Type ◽  
Usage Analysis ◽  
Functional Screens

ABSTRACTEvidence suggests that gut microbes colonize the mammalian intestine through propagation as an adhesive microbial community. A bacterial artificial chromosome (BAC) library of murine bowel microbiota DNA in the surrogate hostEscherichia coliDH10B was screened for enhanced adherence capability. Two out of 5,472 DH10B clones, 10G6 and 25G1, exhibited enhanced capabilities to adhere to inanimate surfaces in functional screens. DNA segments inserted into the 10G6 and 25G1 clones were 52 and 41 kb and included 47 and 41 protein-coding open reading frames (ORFs), respectively. DNA sequence alignments, tetranucleotide frequency, and codon usage analysis strongly suggest that these two DNA fragments are derived from species belonging to the genusBacteroides. Consistent with this finding, a large portion of the predicted gene products were highly homologous to those ofBacteroidesspp. Transposon mutagenesis and subsequent experiments that involved heterologous expression identified two operons associated with enhanced adherence.E. colistrains transformed with the 10a or 25b operon adhered to the surface of intestinal epithelium and colonized the mouse intestine more vigorously than did the control strain. This study has revealed the genetic determinants of unknown commensals (probably resemblingBacteroidesspecies) that enhance the ability of the bacteria to colonize the murine bowel.

scholarly journals Nitrogen Fixation Genes in an EndosymbioticBurkholderia Strain

2001 ◽  
Vol 67 (2) ◽  
pp. 725-732 ◽  
Author(s):  
Daniela Minerdi ◽  
Renato Fani ◽  
Romina Gallo ◽  
Alessandra Boarino ◽  
Paola Bonfante
Keyword(s):  
Genomic Library ◽  
Sequence Similarity ◽  
Bacterial Genome ◽  
Fungal Spores ◽  
Mycorrhizal Fungus ◽  
Prokaryotic Genome ◽  
Arbuscular Mycorrhizal ◽  
Open Reading Frames ◽  
Genome Screening ◽  
High Degree

ABSTRACT In this paper we report the identification and characterization of a DNA region containing putative nif genes and belonging to a Burkholderia endosymbiont of the arbuscular mycorrhizal fungus Gigaspora margarita. A genomic library of total DNA extracted from the fungal spores was also representative of the bacterial genome and was used to investigate the prokaryotic genome. Screening of the library with Azospirillum brasilense nifHDKgenes as the prokaryotic probes led to the identification of a 6,413-bp region. Analysis revealed three open reading frames encoding putative proteins with a very high degree of sequence similarity with the two subunits (NifD and NifK) of the component I and with component II (NifH) of nitrogenase from different diazotrophs. The three genes were arranged in an operon similar to that shown by most archaeal and bacterial diazotrophs. PCR experiments with primers designed on theBurkholderia nifHDK genes and Southern blot analysis demonstrate that they actually belong to the genome of the G. margarita endosymbiont. They offer, therefore, the first sequence for the nif operon described for Burkholderia. Reverse transcriptase PCR experiments with primers designed on theBurkholderia nifH and nifD genes and performed on total RNA extracted from spores demonstrate that the gene expression was limited to the germination phase. A phylogenetic analysis performed on the available nifK sequences placed the endosymbioticBurkholderia close to A. brasilense.

scholarly journals The type II and X cellulose-binding domains of Pseudomonas xylanase A potentiate catalytic activity against complex substrates by a common mechanism

1999 ◽  
Vol 342 (2) ◽  
pp. 473-480 ◽  
Author(s):  
Jaitinder GILL ◽  
Jane E. RIXON ◽  
David N. BOLAM ◽  
Simon MCQUEEN-MASON ◽  
Peter J. SIMPSON ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Plant Cell Wall ◽  
Catalytic Domain ◽  
Wall Material ◽  
Common Mechanism ◽  
Type Ii ◽  
Binding Domains ◽  
Covalently Linked ◽  
Cellulose Binding ◽  
Internal Domain

Xylanase A (Pf Xyn10A), in common with several other Pseudomonas fluorescens subsp. cellulosa polysaccharidases, consists of a Type II cellulose-binding domain (CBD), a catalytic domain (Pf Xyn10ACD) and an internal domain that exhibits homology to Type X CBDs. The Type X CBD of Pf Xyn10A, expressed as a discrete entity (CBDX) or fused to the catalytic domain (Pf Xyn10A′), bound to amorphous and bacterial microcrystalline cellulose with a Ka of 2.5×105 M-1. CBDX exhibited no affinity for soluble forms of cellulose or cello-oligosaccharides, suggesting that the domain interacts with multiple cellulose chains in the insoluble forms of the polysaccharide. Pf Xyn10A′ was 2-3 times more active against cellulose-hemicellulose complexes than Pf Xyn10ACD; however, Pf Xyn10A′ and Pf Xyn10ACD exhibited the same activity against soluble substrates. CBDX did not disrupt the structure of plant-cell-wall material or bacterial microcrystalline cellulose, and did not potentiate Pf Xyn10ACD when not covalently linked to the enzyme. There was no substantial difference in the affinity of full-length Pf Xyn10A and the enzyme's Type II CBD for cellulose. The activity of Pf Xyn10A against cellulose-hemicellulose complexes was similar to that of Pf Xyn10A′, and a derivative of Pf Xyn10A in which the Type II CBD is linked to the Pf Xyn10ACD via a serine-rich linker sequence [Bolam, Cireula, McQueen-Mason, Simpson, Williamson, Rixon, Boraston, Hazlewood and Gilbert (1998) Biochem J. 331, 775-781]. These data indicate that CBDX is functional in Pf Xyn10A and that no synergy, either in ligand binding or in the potentiation of catalysis, is evident between the Type II and X CBDs of the xylanase.

scholarly journals Microlunatus parietis sp. nov., isolated from an indoor wall

2010 ◽  
Vol 60 (10) ◽  
pp. 2420-2423 ◽  
Author(s):  
P. Kämpfer ◽  
J. Schäfer ◽  
N. Lodders ◽  
K. Martin
Keyword(s):  
Diaminopimelic Acid ◽  
Wall Material ◽  
Rrna Gene ◽  
Test Results ◽  
Sequence Comparisons ◽  
Polar Lipid Profile ◽  
Phenotypic Differentiation ◽  
Mycolic Acids ◽  
Diamino Acid ◽  
Physiological And Biochemical

A Gram-positive, coccoid, non-endospore-forming actinobacterium (strain 12-Be-011T) was isolated from indoor wall material. Based on 16S rRNA gene sequence comparisons, strain 12-Be-011T was clearly shown to belong to the genus Microlunatus and was most closely related to Microlunatus panaciterrae Gsoil 954T (95.7 %), Microlunatus soli CC-12602T (94.9 %), Microlunatus ginsengisoli Gsoil 633T (94.8 %), Microlunatus aurantiacus YIM 45721T (95.5 %) and Microlunatus phosphovorus DSM 10555T (94.7 %). The cell-wall peptidoglycan contained ll-diaminopimelic acid as the diagnostic diamino acid. Mycolic acids were absent. The major menaquinone was MK-9(H4). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unknown phospholipids and one unknown glycolipid. The major fatty acids of iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0 supported the affiliation of strain 12-Be-011T to the genus Microlunatus. Physiological and biochemical test results allowed a clear phenotypic differentiation of strain 12-Be-011T from all other species of the genus Microlunatus. Hence, strain 12-Be-011T can be regarded as a representative of a novel species, for which the name Microlunatus parietis sp. nov. is proposed, with the type strain 12-Be-011T (=DSM 22083T=CCM 7636T).

scholarly journals Identification and Sequencing of β-Myrcene Catabolism Genes from Pseudomonas sp. Strain M1

1999 ◽  
Vol 65 (7) ◽  
pp. 2871-2876 ◽  
Author(s):  
Sandra Iurescia ◽  
Andrea M. Marconi ◽  
Daniela Tofani ◽  
Augusto Gambacorta ◽  
Annalisa Paternò ◽  
...  
Keyword(s):  
Genomic Library ◽  
Enrichment Culture ◽  
Open Reading Frames ◽  
Gas Chromatography Mass Spectrometry ◽  
Complete Agreement ◽  
Wild Type ◽  
Genomic Insert ◽  
The One ◽  
Acyl Coenzyme A ◽  
Reading Frames

ABSTRACT The M1 strain, able to grow on β-myrcene as the sole carbon and energy source, was isolated by an enrichment culture and identified as a Pseudomonas sp. One β-myrcene-negative mutant, called N22, obtained by transposon mutagenesis, accumulated (E)-2-methyl-6-methylen-2,7-octadien-1-ol (or myrcen-8-ol) as a unique β-myrcene biotransformation product. This compound was identified by gas chromatography-mass spectrometry. We cloned and sequenced the DNA regions flanking the transposon and used these fragments to identify the M1 genomic library clones containing the wild-type copy of the interrupted gene. One of the selected cosmids, containing a 22-kb genomic insert, was able to complement the N22 mutant for growth on β-myrcene. A 5,370-bp-long sequence spanning the region interrupted by the transposon in the mutant was determined. We identified four open reading frames, named myrA,myrB, myrC, and myrD, which can potentially code for an aldehyde dehydrogenase, an alcohol dehydrogenase, an acyl-coenzyme A (CoA) synthetase, and an enoyl-CoA hydratase, respectively. myrA, myrB, andmyrC are likely organized in an operon, since they are separated by only 19 and 36 nucleotides (nt), respectively, and no promoter-like sequences have been found in these regions. ThemyrD gene starts 224 nt upstream of myrA and is divergently transcribed. The myrB sequence was found to be completely identical to the one flanking the transposon in the mutant. Therefore, we could ascertain that the transposon had been inserted inside the myrB gene, in complete agreement with the accumulation of (E)-2-methyl-6-methylen-2,7-octadien-1-ol by the mutant. Based on sequence and biotransformation data, we propose a pathway for β-myrcene catabolism in Pseudomonas sp. strain M1.

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