Journal articles: 'ALG1'

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Ji, Shi-Qi, Bing Wang, Ming Lu, and Fu-Li Li. "Defluviitalea phaphyphila sp. nov., a Novel Thermophilic Bacterium That Degrades Brown Algae." Applied and Environmental Microbiology 82, no. 3 (November 20, 2015): 868–77. http://dx.doi.org/10.1128/aem.03297-15.

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ABSTRACTBrown algae are one of the largest groups of oceanic primary producers for CO2removal and carbon sinks for coastal regions. However, the mechanism for brown alga assimilation remains largely unknown in thermophilic microorganisms. In this work, a thermophilic alginolytic community was enriched from coastal sediment, from which an obligate anaerobic and thermophilic bacterial strain, designated Alg1, was isolated. Alg1 shared a 16S rRNA gene identity of 94.6% withDefluviitalea saccharophilaLIND6LT2T. Phenotypic, chemotaxonomic, and phylogenetic studies suggested strain Alg1 represented a novel species of the genusDefluviitalea, for which the nameDefluviitalea phaphyphilasp. nov. is proposed. Alg1 exhibited an intriguing ability to convert carbohydrates of brown algae, including alginate, laminarin, and mannitol, to ethanol and acetic acid. Three gene clusters participating in this process were predicted to be in the genome, and candidate enzymes were successfully expressed, purified, and characterized. Six alginate lyases were demonstrated to synergistically deconstruct alginate into unsaturated monosaccharide, followed by one uronic acid reductase and two 2-keto-3-deoxy-d-gluconate (KDG) kinases to produce pyruvate. A nonclassical mannitol 1-phosphate dehydrogenase, catalyzingd-mannitol 1-phosphate to fructose 1-phosphate in the presence of NAD+, and one laminarase also were disclosed. This work revealed that a thermophilic brown alga-decomposing system containing numerous novel thermophilic alginate lyases and a unique mannitol 1-phosphate dehydrogenase was adopted by the natural ethanologenic strain Alg1 during the process of evolution in hostile habitats.

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Truong, Vinh. "Effects of type and concentration of alginate on microencapsulation characteristics of lime essential oil (Citrus aurantifolia) produced by extrusion-dripping methods." Journal of Agriculture and Development 19, no. 01 (February 28, 2020): 65–76. http://dx.doi.org/10.52997/jad.9.01.2020.

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The extrusion-dripping method to produce alginate-calcium beads for microencapsulation of lime oil (Citrus aurantifolia) was carried out in this study. The experimental range of alginate concentration was from 1 to 4%. Above 1% alginate concentration, viscosity was pseudoplastic behavior. The size (1.52 - 1.57 mm) and sphericity (above 95%) of the beads were maximum at alginate concentration of 2 - 3%. The extrusion-dripping method was not applicable when alginate concentration was over 3.5% due to the high viscosity resulting in low sphericity. The two types of alginates with a protein content of 9% (alg1) and 2% (alg2) had the same microencapsulation yield of 73 - 74%. However, the solid recovery of alg2 (98.99%) was much higher than that of alg1 (52.71%). This is because alg2 has a higher purity and if it is used in production, it is easier to control the content of active ingredients and reduce the amount of organic waste that is harmful to the environment compared to alg1.

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Gao, X. D. "Physical interactions between the Alg1, Alg2, and Alg11 mannosyltransferases of the endoplasmic reticulum." Glycobiology 14, no. 6 (January 22, 2004): 559–70. http://dx.doi.org/10.1093/glycob/cwh072.

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Ramírez, Ana S., Jérémy Boilevin, Chia-Wei Lin, Bee Ha Gan, Daniel Janser, Markus Aebi, Tamis Darbre, Jean-Louis Reymond, and Kaspar P. Locher. "Chemo-enzymatic synthesis of lipid-linked GlcNAc2Man5 oligosaccharides using recombinant Alg1, Alg2 and Alg11 proteins." Glycobiology 27, no. 8 (June 1, 2017): 726–33. http://dx.doi.org/10.1093/glycob/cwx045.

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JOUSSE-JOULIN, SANDRINE, MARIA ANTONIETTA d’AGOSTINO, THIERRY MARHADOUR, JEAN DAVID ALBERT, JACQUES BENTIN, ISABELLE CHARY VALCKENAERE, FABIEN ETCHEPARE, et al. "Reproducibility of Joint Swelling Assessment by Sonography in Patients with Long-lasting Rheumatoid Arthritis (SEA-Repro Study Part II)." Journal of Rheumatology 37, no. 5 (March 15, 2010): 938–45. http://dx.doi.org/10.3899/jrheum.090881.

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Objective.To evaluate the intraobserver and interobserver reproducibility of B-mode and power Doppler (PD) sonography in patients with active long-standing rheumatoid arthritis (RA) comparatively with clinical data.Methods.In each of 7 patients being considered for a change in their RA treatment regimen, 7 healthcare professionals examined the 28 joints used in the Disease Activity Score 28-joint count (DAS28). Then 7 sonographers examined each of the 7 patients twice, using previously published B-mode and PD grading systems. The clinical reference standard was presence of synovitis according to at least 4/7 examiners. The sonographic reference standard was at least grade 1 (ALG1) or 2 (ALG2) synovitis according to at least 4/7 sonographers. Interobserver reproducibility of sonography was assessed versus the sonographer having the best intraobserver reproducibility. Agreement was measured by Cohen’s kappa statistic.Results.Intraobserver and interobserver reproducibility of B-mode and PD used separately was fair to good. Agreement between clinicians and sonographers at all sites using B-mode, PD, and both was 0.46, 0.37, and 0.36, respectively, for grade 1 synovitis; and 0.58, 0.19, and 0.19 for grade 2 synovitis. The number of joints with synovitis was smaller by physical examination (36.7%) than by B-mode with ALG1 (58.6%; p < 0.001). The number of joints with synovitis was higher by physical examination than by PD with both ALG1 (17.8%; p < 0.0001) and ALG2 (6.6%; p < 0.0001).Conclusion.PD findings explain most of the difference between clinical and sonographic joint assessments for synovitis in patients with long-standing RA.

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Zhang, Wenyue, Philip M. James, Bobby G. Ng, Xueli Li, Baoyun Xia, Jiang Rong, Ghazia Asif, et al. "A Novel N-Tetrasaccharide in Patients with Congenital Disorders of Glycosylation, Including Asparagine-Linked Glycosylation Protein 1, Phosphomannomutase 2, and Mannose Phosphate Isomerase Deficiencies." Clinical Chemistry 62, no. 1 (January 1, 2016): 208–17. http://dx.doi.org/10.1373/clinchem.2015.243279.

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Abstract BACKGROUND Primary deficiencies in mannosylation of N-glycans are seen in a majority of patients with congenital disorders of glycosylation (CDG). We report the discovery of a series of novel N-glycans in sera, plasma, and cultured skin fibroblasts from patients with CDG having deficient mannosylation. METHOD We used LC-MS/MS and MALDI-TOF-MS analysis to identify and quantify a novel N-linked tetrasaccharide linked to the protein core, an N-tetrasaccharide (Neu5Acα2,6Galβ1,4-GlcNAcβ1,4GlcNAc) in plasma, serum glycoproteins, and a fibroblast lysate from patients with CDG caused by ALG1 [ALG1 (asparagine-linked glycosylation protein 1), chitobiosyldiphosphodolichol β-mannosyltransferase], PMM2 (phosphomannomutase 2), and MPI (mannose phosphate isomerase). RESULTS Glycoproteins in sera, plasma, or cell lysate from ALG1-CDG, PMM2-CDG, and MPI-CDG patients had substantially more N-tetrasaccharide than unaffected controls. We observed a >80% decline in relative concentrations of the N-tetrasaccharide in MPI-CDG plasma after mannose therapy in 1 patient and in ALG1-CDG fibroblasts in vitro supplemented with mannose. CONCLUSIONS This novel N-tetrasaccharide could serve as a diagnostic marker of ALG1-, PMM2-, or MPI-CDG for screening of these 3 common CDG subtypes that comprise >70% of CDG type I patients. Its quantification by LC-MS/MS may be useful for monitoring therapeutic efficacy of mannose. The discovery of these small N-glycans also indicates the presence of an alternative pathway in N-glycosylation not recognized previously, but its biological significance remains to be studied.

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Dhamija, Radhika, and Chelsea Chambers. "Clinical and Molecular Characterization of ALG1-CDG." Pediatric Neurology Briefs 30, no. 2 (April 5, 2016): 14. http://dx.doi.org/10.15844/pedneurbriefs-30-2-5.

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Jain, Sumita, and Dennis E. Ohman. "Deletion of algK in Mucoid Pseudomonas aeruginosa Blocks Alginate Polymer Formation and Results in Uronic Acid Secretion." Journal of Bacteriology 180, no. 3 (February 1, 1998): 634–41. http://dx.doi.org/10.1128/jb.180.3.634-641.1998.

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ABSTRACT Chronic pulmonary infection with Pseudomonas aeruginosais a common and serious problem in patients with cystic fibrosis (CF). The P. aeruginosa isolates from these patients typically have a mucoid colony morphology due to overproduction of the exopolysaccharide alginate, which contributes to the persistence of the organisms in the CF lung. Most of the alginate biosynthetic genes are clustered in the algD operon, located at 34 min on the chromosome. Alginate biosynthesis begins with the formation of an activated monomer, GDP-mannuronate, which is known to occur via the products of the algA, algC, andalgD genes. Polymannuronate forms in the periplasm, but the gene products involved in mannuronate translocation across the inner membrane and its polymerization are not known. One locus of the operon which remained uncharacterized was a new gene called algKbetween alg44 and algE. We sequencedalgK from the mucoid CF isolate FRD1 and expressed it inEscherichia coli, which revealed a polypeptide of the predicted size (52 kDa). The sequence of AlgK showed an apparent signal peptide characteristic of a lipoprotein. AlgK-PhoA fusion proteins were constructed and shown to be active, indicating that AlgK has a periplasmic subcellular localization. To test the phenotype of an AlgK− mutant, the algK coding sequence was replaced with a nonpolar gentamicin resistance cassette to avoid polar effects on genes downstream of algK that are essential for polymer formation. The algKΔ mutant was nonmucoid, demonstrating that AlgK was required for alginate production. Also, AlgK− mutants demonstrated a small-colony phenotype on L agar, suggesting that the loss of AlgK also caused a growth defect. The mutant phenotypes were complemented by a plasmid expressingalgK in trans. When the algKΔ mutation was placed in an algJ::Tn501background, where algA was not expressed due to polar transposon effects, the growth defect was not observed. AlgK− mutants appeared to accumulate a toxic extracellular product, and we hypothesized that this could be an unpolymerized alginate precursor. High levels of low-molecular-weight uronic acid were produced by the AlgK− mutant. When AlgK−culture supernatants were subjected to dialysis, high levels of uronic acids diffused out of the dialysis sac, and no uronic acids were detectable after extensive dialysis. In contrast, the mucoid wild-type strain produced only polymerized uronic acids (i.e., alginate), whereas the algKΔ algJ::Tn501 mutant produced no uronic acids. Thus, the alginate pathway in an AlgK− mutant was blocked after transport but at a step before polymerization, suggesting that AlgK plays an important role in the polymerization of mannuronate to alginate.

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Albuquerque-Wendt, Andreia, Hermann J. Hütte, Falk F. R. Buettner, Françoise H. Routier, and Hans Bakker. "Membrane Topological Model of Glycosyltransferases of the GT-C Superfamily." International Journal of Molecular Sciences 20, no. 19 (September 29, 2019): 4842. http://dx.doi.org/10.3390/ijms20194842.

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Glycosyltransferases that use polyisoprenol-linked donor substrates are categorized in the GT-C superfamily. In eukaryotes, they act in the endoplasmic reticulum (ER) lumen and are involved in N-glycosylation, glypiation, O-mannosylation, and C-mannosylation of proteins. We generated a membrane topology model of C-mannosyltransferases (DPY19 family) that concurred perfectly with the 13 transmembrane domains (TMDs) observed in oligosaccharyltransferases (STT3 family) structures. A multiple alignment of family members from diverse organisms highlighted the presence of only a few conserved amino acids between DPY19s and STT3s. Most of these residues were shown to be essential for DPY19 function and are positioned in luminal loops that showed high conservation within the DPY19 family. Multiple alignments of other eukaryotic GT-C families underlined the presence of similar conserved motifs in luminal loops, in all enzymes of the superfamily. Most GT-C enzymes are proposed to have an uneven number of TDMs with 11 (POMT, TMTC, ALG9, ALG12, PIGB, PIGV, and PIGZ) or 13 (DPY19, STT3, and ALG10) membrane-spanning helices. In contrast, PIGM, ALG3, ALG6, and ALG8 have 12 or 14 TMDs and display a C-terminal dilysine ER-retrieval motif oriented towards the cytoplasm. We propose that all members of the GT-C superfamily are evolutionary related enzymes with preserved membrane topology.

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Jain, Sumita, and Dennis E. Ohman. "Role of an Alginate Lyase for Alginate Transport in Mucoid Pseudomonas aeruginosa." Infection and Immunity 73, no. 10 (October 2005): 6429–36. http://dx.doi.org/10.1128/iai.73.10.6429-6436.2005.

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ABSTRACT The opportunistic pathogen Pseudomonas aeruginosa secretes a capsule-like polysaccharide called alginate that is important for evasion of host defenses, especially during chronic pulmonary disease of patients with cystic fibrosis (CF). Most proteins for alginate biosynthesis are encoded by the 12-gene algD operon. Interestingly, this operon also encodes AlgL, a lyase that degrades alginate. Mutants lacking AlgG, AlgK, or AlgX, also encoded by the operon, synthesize alginate polymers that are digested by the coregulated protein AlgL. We examined the phenotype of an ΔalgL mutation in the highly mucoid CF isolate FRD1. Generating a true ΔalgL mutant was possible only when the algD operon was under the control of a LacIq-repressed trc promoter. Upon induction of alginate production with isopropyl-β-d-thiogalactopyranoside, the ΔalgL mutant cells were lysed within a few hours. Electron micrographs of the ΔalgL mutant showed that alginate polymers accumulated in the periplasm, which ultimately burst the bacterial cell wall. The requirement of AlgL in an alginate-overproducing strain led to a new model for alginate secretion in which a multiprotein secretion complex (or scaffold, that includes AlgG, AlgK, AlgX, and AlgL) guides new polymers through the periplasm for secretion across the outer membrane. In this model, AlgL is bifunctional with a structural role in the scaffold and a role in degrading free alginate polymers in the periplasm.

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Rehman, Zahid U., Yajie Wang, M. Fata Moradali, Iain D. Hay, and Bernd H. A. Rehm. "Insights into the Assembly of the Alginate Biosynthesis Machinery in Pseudomonas aeruginosa." Applied and Environmental Microbiology 79, no. 10 (March 15, 2013): 3264–72. http://dx.doi.org/10.1128/aem.00460-13.

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ABSTRACTPseudomonas aeruginosais an opportunistic pathogen of particular significance to cystic fibrosis patients. This bacterium produces the exopolysaccharide alginate, which is an indicator of poor prognosis for these patients. The proteins required for alginate polymerization and secretion are encoded by genes organized in a single operon; however, the existence of internal promoters has been reported. It has been proposed that these proteins form a multiprotein complex which extends from the inner to outer membrane. Here, experimental evidence supporting such a multiprotein complex was obtained via mutual stability analysis, pulldown assays, and coimmunoprecipitation. The impact of the absence of single proteins or subunits on this multiprotein complex, i.e., on the stability of potentially interacting proteins, as well as on alginate production was investigated. Deletion ofalgKin an alginate-overproducing strain, PDO300, interfered with the polymerization of alginate, suggesting that in the absence of AlgK, the polymerase and copolymerase subunits, Alg8 and Alg44, are destabilized. Based on mutual stability analysis, interactions between AlgE (outer membrane), AlgK (periplasm), AlgX (periplasm), Alg44 (inner membrane), Alg8 (inner membrane), and AlgG (periplasm) were proposed. Coimmunoprecipitation using a FLAG-tagged variant of AlgE further demonstrated its interaction with AlgK. Pulldown assays using histidine-tagged AlgK showed that AlgK interacts with AlgX, which in turn was also copurified with histidine-tagged Alg44. Detection of AlgG and AlgE in PAO1 supported the existence of internal promoters controlling expression of the respective genes. Overall experimental evidence was provided for the existence of a multiprotein complex required for alginate polymerization and secretion.

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Rohlfing, A. K., S. Rust, J. Reunert, M. Tirre, I. Du Chesne, Sa Wemhoff, F. Meinhardt, H. Hartmann, A. M. Das, and T. Marquardt. "ALG1-CDG: A new case with early fatal outcome." Gene 534, no. 2 (January 2014): 345–51. http://dx.doi.org/10.1016/j.gene.2013.10.013.

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Franklin, Michael J., and Dennis E. Ohman. "Mutant Analysis and Cellular Localization of the AlgI, AlgJ, and AlgF Proteins Required for O Acetylation of Alginate in Pseudomonas aeruginosa." Journal of Bacteriology 184, no. 11 (June 1, 2002): 3000–3007. http://dx.doi.org/10.1128/jb.184.11.3000-3007.2002.

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ABSTRACT Alginate is an extracellular polysaccharide produced by mucoid strains of Pseudomonas aeruginosa that are typically isolated from the pulmonary tracts of chronically infected cystic fibrosis patients. Alginate is a linear polymer of d-mannuronate and l-guluronate with O-acetyl ester linkages on the O-2 and/or O-3 position of the mannuronate residues. The presence of O-acetyl groups plays an important role in the ability of the polymer to act as a virulence factor, and the algF, algJ, and algI genes are known to be essential for the addition of O-acetyl groups to alginate. To better understand the mechanism of O acetylation of alginate, the cellular locations of the AlgI, AlgJ, and AlgF proteins were determined. For these studies, defined nonpolar algI, algJ, and algF deletion mutants of P. aeruginosa strain FRD1 were constructed, and each mutant produced alginate lacking O-acetyl groups. Expression of algI, algJ, or algF in trans in the corresponding mutant complemented each O acetylation defect. Random phoA (alkaline phosphatase [AP] gene) fusions to algF, algJ, and algI were constructed. All in-frame fusions to algF and algJ had AP activity, indicating that both AlgF and AlgJ were exported to the periplasm. Immunoblot analysis of spheroplasts and periplasmic fractions showed that AlgF was released with the periplasmic contents but that AlgJ remained with the spheroplast fraction. An N-terminal sequence analysis of AlgJ showed that its putative AlgJ signal peptide was not cleaved, suggesting that AlgJ is anchored to the cytoplasmic membrane by its uncleaved signal peptide. AP gene fusions were also used to map the membrane topology of AlgI, and the results suggest that it is an integral membrane protein with seven transmembrane domains. These results suggest that AlgI-AlgJ-AlgF may form a complex in the membrane that is the reaction center for O acetylation of alginate.

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Peñaloza-Vázquez, Alejandro, Mohamed K. Fakhr, Ana M. Bailey, and Carol L. Bender. "AlgR functions in algC expression and virulence in Pseudomonas syringae pv. syringae." Microbiology 150, no. 8 (August 1, 2004): 2727–37. http://dx.doi.org/10.1099/mic.0.27199-0.

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Pseudomonas syringae pv. syringae strain FF5 is a phytopathogen associated with a rapid dieback on ornamental pear trees. P. syringae and the human pathogen Pseudomonas aeruginosa produce the exopolysaccharide alginate, a copolymer of mannuronic and guluronic acid. In P. aeruginosa, the response regulator AlgR (AlgR1) is required for transcription of algC and algD, which encode key enzymes in the alginate biosynthetic pathway. In P. syringae FF5, however, algR is not required for the activation of algD. Interestingly, algR mutants of P. syringae remain nonmucoid, indicating an undefined role for this response regulator in alginate biosynthesis. In the current study, the algC promoter region was cloned from P. syringae pv. syringae strain FF5, and sequence analysis of the algC promoter indicated the presence of potential binding sites for AlgR and σ 54, the alternative sigma factor encoded by rpoN. The algC promoter from P. syringae FF5 (PsalgC) was cloned upstream of a promoterless glucuronidase gene (uidA), and the PsalgC–uidA transcriptional fusion was used to monitor algC expression in strains FF5.32 (algR mutant of P. syringae FF5) and PG4180.K2 (rpoN mutant of P. syringae pv. glycinea PG4180). Expression of the PsalgC–uidA fusion was fourfold lower in both the algR and rpoN mutants as compared to respective wild-type strains, indicating that both AlgR and σ 54 are required for full activation of algC transcription in P. syringae pv. syringae. AlgR from P. syringae was successfully overproduced in Escherichia coli as a C-terminal translational fusion to the maltose-binding protein (MBP). Gel shift experiments indicated that MBP–AlgR binds strongly to the algC promoter region. Biological assays demonstrated that the algR mutant was significantly impaired in both pathogenicity and epiphytic fitness as compared to the wild-type strain. These results, along with the gene expression studies, indicate that AlgR has a positive role in the activation of algC in P. syringae and contributes to both virulence and epiphytic fitness. Furthermore, the symptoms observed with wild-type P. syringae FF5 suggest that this strain can move systemically in leaf tissue, and that a functional copy of algR is required for systemic movement.

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Ng, Bobby G., Sergey A. Shiryaev, Daisy Rymen, Erik A. Eklund, Kimiyo Raymond, Martin Kircher, Jose E. Abdenur, et al. "ALG1-CDG: Clinical and Molecular Characterization of 39 Unreported Patients." Human Mutation 37, no. 7 (March 21, 2016): 653–60. http://dx.doi.org/10.1002/humu.22983.

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Jaeken, Jaak, Dirk Lefeber, and Gert Matthijs. "Clinical utility gene card for: ALG1 defective congenital disorder of glycosylation." European Journal of Human Genetics 23, no. 10 (February 4, 2015): 1431. http://dx.doi.org/10.1038/ejhg.2015.9.

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Morava, E., J. Vodopiutz, D. J. Lefeber, A. R. Janecke, W. M. Schmidt, S. Lechner, C. B. Item, et al. "Defining the Phenotype in Congenital Disorder of Glycosylation Due to ALG1 Mutations." PEDIATRICS 130, no. 4 (September 10, 2012): e1034-e1039. http://dx.doi.org/10.1542/peds.2011-2711.

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Harshman, Lyndsay A., Bobby G. Ng, Hudson H. Freeze, Pamela Trapane, Anna Dolezal, Patrick D. Brophy, and Jane E. Brumbaugh. "Congenital nephrotic syndrome in an infant with ALG1 -congenital disorder of glycosylation." Pediatrics International 58, no. 8 (June 21, 2016): 785–88. http://dx.doi.org/10.1111/ped.12988.

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Jia, Ji-Xiang, Ndayambaje Yvan Kalisa, Tian-Tian Lu, Zhifang Zhou, Xiao-Dong Gao, and Ning Wang. "Chemo-enzymatic synthesis of the ALG1-CDG biomarker and evaluation of its immunogenicity." Bioorganic & Medicinal Chemistry Letters 30, no. 24 (December 2020): 127614. http://dx.doi.org/10.1016/j.bmcl.2020.127614.

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Revers, L., I. B. H. Wilson, M. C. Webberley, and S. L. Flitsch. "The potential dolichol recognition sequence of β-1,4-mannosyltransferase is not required for enzymic activity using phytanyl-pyrophosphoryl-α-N,N'- diacetylchitobioside as acceptor." Biochemical Journal 299, no. 1 (April 1, 1994): 23–27. http://dx.doi.org/10.1042/bj2990023.

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The ALG1 gene of Saccharomyces cerevisiae encodes beta-1,4-mannosyltransferase, an essential membrane-associated enzyme involved in the assembly of dolichyl-linked oligosaccharide precursors for N-glycosylation [Albright and Robbins (1990) J. Biol. Chem. 265, 7042-7049], which catalyses the transfer of a mannose residue from GDP-mannose to dolichyl-pyrophosphoryl-alpha-N,N'- diacetylchitobioside; it also possesses a putative transmembrane domain, bearing an 11-amino-acid consensus sequence, which has been proposed to mediate dolichol recognition. Here we report the construction and bacterial expression of a mutant beta-1,4-mannosyltransferase derived from ALG1, which carries a 34-amino-acid deletion resulting in the absence of the entire N-terminal transmembrane domain. This truncated enzyme has an apparent Km value of 17 microM for phytanyl-pyrophosphoryl-alpha-N,N'-diacetylchitobioside, a known acceptor for beta-1,4-mannosyltransferase [Flitsch, Pinches, Taylor and Turner (1992) J. Chem. Soc., Perkin Trans. 1, 2087-2093]. The intact enzyme, expressed in the same system, has an apparent Km value of 25 microM. These figures are in good agreement with previously reported values for wild-type beta-1,4-mannosyl-transferase incubated with the natural dolichyl-linked substrate. Gel-filtration chromatography (before and after beta-mannosidase digestion) of the products of both forms of the enzyme verifies the formation of Man beta 1->4GlcNAc beta 1->4GlcNAc. We therefore conclude that the putative dolichol recognition sequence is not necessary for recognition of the phytanyl analogue of its natural dolichol substrate and suggest it probably also is not needed for its natural substrate.

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ATIFY, Elmostafa, Cherki DAOUI, and Ahmed BOUMEZZOUGH. "Using A Fuzzy Number Error Correction Approach to Improve Algorithms in Blind Identification." Indonesian Journal of Electrical Engineering and Computer Science 3, no. 2 (August 1, 2016): 410. http://dx.doi.org/10.11591/ijeecs.v3.i2.pp410-419.

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As part of a detailed study on blind identification of Gaussian channels, the main purpose was to propose an algorithm based on cumulants and fuzzy number approach involved throughout the whole process of identification. Our objective was to compare the new design of the algorithm to the old one using the higher order cumulants, namely Alg1, Algat and the Giannakis algorithm. We were able to demonstrate that the proposed method -fuzzy number error correction- increases the performance of the algorithm by calculating the ratio of squared errors of ALGaT and AlgatF. The method can be applied to any algorithm for more improvement and effinciency.

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Bengtson, Per, Bobby G. Ng, Jaak Jaeken, Gert Matthijs, Hudson H. Freeze, and Erik A. Eklund. "Serum transferrin carrying the xeno-tetrasaccharide NeuAc-Gal-GlcNAc2 is a biomarker of ALG1-CDG." Journal of Inherited Metabolic Disease 39, no. 1 (September 3, 2015): 107–14. http://dx.doi.org/10.1007/s10545-015-9884-y.

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Grabińska, Kariona A., Sudip K. Ghosh, Ziqiang Guan, Jike Cui, Christian R. H. Raetz, Phillips W. Robbins, and John Samuelson. "Dolichyl-Phosphate-Glucose Is Used To Make O-Glycans on Glycoproteins of Trichomonas vaginalis." Eukaryotic Cell 7, no. 8 (June 13, 2008): 1344–51. http://dx.doi.org/10.1128/ec.00061-08.

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ABSTRACT Trichomonas vaginalis, the protist that causes vaginal itching, has a huge genome with numerous gene duplications. Recently we found that Trichomonas has numerous genes encoding putative dolichyl-phosphate-glucose (Dol-P-Glc) synthases (encoded by ALG5 genes) despite the fact that Trichomonas lacks the glycosyltransferases (encoded by ALG6, ALG8, and ALG10 genes) that use Dol-P-Glc to glucosylate dolichyl-PP-linked glycans. In addition, Trichomonas does not have a canonical DPM1 gene, encoding a dolichyl-P-mannose (Dol-P-Man) synthase. Here we show Trichomonas membranes have roughly 300 times the Dol-P-Glc synthase activity of Saccharomyces cerevisiae membranes and about one-fifth the Dol-P-Man synthase activity of Saccharomyces membranes. Endogenous Dol-P-hexoses of Trichomonas are relatively abundant and contain 16 isoprene units. Five paralogous Trichomonas ALG5 gene products have Dol-P-Glc synthase activity when expressed as recombinant proteins, and these Trichomonas Alg5s correct a carboxypeptidase N glycosylation defect in a Saccharomyces alg5 mutant in vivo. A recombinant Trichomonas Dpm1, which is deeply divergent in its sequence, has Dol-P-Man synthase activity. When radiolabeled Dol-P-Glc is incubated with Trichomonas membranes, Glc is incorporated into reducing and nonreducing sugars of O-glycans of endogenous glycoproteins. To our knowledge, this is the first demonstration of Dol-P-Glc as a sugar donor for O-glycans on glycoproteins.

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Albright, C. F., and R. W. Robbins. "The sequence and transcript heterogeneity of the yeast gene ALG1, an essential mannosyltransferase involved in N-glycosylation." Journal of Biological Chemistry 265, no. 12 (April 1990): 7042–49. http://dx.doi.org/10.1016/s0021-9258(19)39256-7.

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Xu, Xin-Xin, Sheng-Tao Li, Ning Wang, Toshihiko Kitajima, Takehiko Yoko-o, Morihisa Fujita, Hideki Nakanishi, and Xiao-Dong Gao. "Structural and functional analysis of Alg1 beta-1,4 mannosyltransferase reveals the physiological importance of its membrane topology." Glycobiology 28, no. 10 (July 18, 2018): 741–53. http://dx.doi.org/10.1093/glycob/cwy060.

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Mori, Tetsushi, Mami Takahashi, Reiji Tanaka, Hideo Miyake, Toshiyuki Shibata, Seinen Chow, Kouichi Kuroda, Mitsuyoshi Ueda, and Haruko Takeyama. "Falsirhodobacter sp. alg1 Harbors Single Homologs of Endo and Exo-Type Alginate Lyases Efficient for Alginate Depolymerization." PLOS ONE 11, no. 5 (May 13, 2016): e0155537. http://dx.doi.org/10.1371/journal.pone.0155537.

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Li, Sheng-Tao, Ning Wang, Sha Xu, Jian Yin, Hideki Nakanishi, Neta Dean, and Xiao-Dong Gao. "Quantitative study of yeast Alg1 beta-1, 4 mannosyltransferase activity, a key enzyme involved in protein N-glycosylation." Biochimica et Biophysica Acta (BBA) - General Subjects 1861, no. 1 (January 2017): 2934–41. http://dx.doi.org/10.1016/j.bbagen.2016.09.023.

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Lipiński, Patryk, Karolina M. Stępień, Elżbieta Ciara, Anna Tylki-Szymańska, and Aleksandra Jezela-Stanek. "Skeletal and Bone Mineral Density Features, Genetic Profile in Congenital Disorders of Glycosylation: Review." Diagnostics 11, no. 8 (August 9, 2021): 1438. http://dx.doi.org/10.3390/diagnostics11081438.

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Congenital disorders of glycosylation (CDGs) are a heterogeneous group of disorders with impaired glycosylation of proteins and lipids. These conditions have multisystemic clinical manifestations, resulting in gradually progressive complications including skeletal involvement and reduced bone mineral density. Contrary to PMM2-CDG, all remaining CDG, including ALG12-CDG, ALG3-CDG, ALG9-CDG, ALG6-CDG, PGM3-CDG, CSGALNACT1-CDG, SLC35D1-CDG and TMEM-165, are characterized by well-defined skeletal dysplasia. In some of them, prenatal-onset severe skeletal dysplasia is observed associated with early death. Osteoporosis or osteopenia are frequently observed in all CDG types and are more pronounced in adults. Hormonal dysfunction, limited mobility and inadequate diet are common risk factors for reduced bone mineral density. Skeletal involvement in CDGs is underestimated and, thus, should always be carefully investigated and managed to prevent fractures and chronic pain. With the advent of new therapeutic developments for CDGs, the severity of skeletal complications may be reduced. This review focuses on possible mechanisms of skeletal manifestations, risk factors for osteoporosis, and bone markers in reported paediatric and adult CDG patients.

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Leitão, J. H., and I. Sá-Correia. "Oxygen-dependent upregulation of transcription of alginate genes algA, algC and algD in Pseudomonas aeruginosa." Research in Microbiology 148, no. 1 (January 1997): 37–43. http://dx.doi.org/10.1016/s0923-2508(97)81898-0.

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Franklin, Michael J., Stephanie A. Douthit, and Marcella A. McClure. "Evidence that the algI/algJ Gene Cassette, Required for O Acetylation of Pseudomonas aeruginosa Alginate, Evolved by Lateral Gene Transfer." Journal of Bacteriology 186, no. 14 (July 15, 2004): 4759–73. http://dx.doi.org/10.1128/jb.186.14.4759-4773.2004.

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ABSTRACT Pseudomonas aeruginosa strains, isolated from chronically infected patients with cystic fibrosis, produce the O-acetylated extracellular polysaccharide, alginate, giving these strains a mucoid phenotype. O acetylation of alginate plays an important role in the ability of mucoid P. aeruginosa to form biofilms and to resist complement-mediated phagocytosis. The O-acetylation process is complex, requiring a protein with seven transmembrane domains (AlgI), a type II membrane protein (AlgJ), and a periplasmic protein (AlgF). The cellular localization of these proteins suggests a model wherein alginate is modified at the polymer level after the transport of O-acetyl groups to the periplasm. Here, we demonstrate that this mechanism for polysaccharide esterification may be common among bacteria, since AlgI homologs linked to type II membrane proteins are found in a variety of gram-positive and gram-negative bacteria. In some cases, genes for these homologs have been incorporated into polysaccharide biosynthetic operons other than for alginate biosynthesis. The phylogenies of AlgI do not correlate with the phylogeny of the host bacteria, based on 16S rRNA analysis. The algI homologs and the gene for their adjacent type II membrane protein present a mosaic pattern of gene arrangement, suggesting that individual components of the multigene cassette, as well as the entire cassette, evolved by lateral gene transfer. AlgJ and the other type II membrane proteins, although more diverged than AlgI, contain conserved motifs, including a motif surrounding a highly conserved histidine residue, which is required for alginate O-acetylation activity by AlgJ. The AlgI homologs also contain an ordered series of motifs that included conserved amino acid residues in the cytoplasmic domain CD-4; the transmembrane domains TM-C, TM-D, and TM-E; and the periplasmic domain PD-3. Site-directed mutagenesis studies were used to identify amino acids important for alginate O-acetylation activity, including those likely required for (i) the interaction of AlgI with the O-acetyl precursor in the cytoplasm, (ii) the export of the O-acetyl group across the cytoplasmic membrane, and (iii) the transfer of the O-acetyl group to a periplasmic protein or to alginate. These results indicate that AlgI belongs to a family of membrane proteins required for modification of polysaccharides and that a mechanism requiring an AlgI homolog and a type II membrane protein has evolved by lateral gene transfer for the esterification of many bacterial extracellular polysaccharides.

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Gao, Xiao-Dong, Hiroyuki Tachikawa, Takashi Sato, Yoshifumi Jigami, and Neta Dean. "Alg14 Recruits Alg13 to the Cytoplasmic Face of the Endoplasmic Reticulum to Form a Novel Bipartite UDP-N-acetylglucosamine Transferase Required for the Second Step of N-Linked Glycosylation." Journal of Biological Chemistry 280, no. 43 (August 12, 2005): 36254–62. http://dx.doi.org/10.1074/jbc.m507569200.

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N-linked glycosylation requires the synthesis of an evolutionarily conserved lipid-linked oligosaccharide (LLO) precursor that is essential for glycoprotein folding and stability. Despite intense research, several of the enzymes required for LLO synthesis have not yet been identified. Here we show that two poorly characterized yeast proteins known to be required for the synthesis of the LLO precursor, GlcNAc2-PP-dolichol, interact to form an unusual hetero-oligomeric UDP-GlcNAc transferase. Alg13 contains a predicted catalytic domain, but lacks any membrane-spanning domains. Alg14 spans the membrane but lacks any sequences predicted to play a direct role in sugar catalysis. We show that Alg14 functions as a membrane anchor that recruits Alg13 to the cytosolic face of the ER, where catalysis of GlcNAc2-PP-dol occurs. Alg13 and Alg14 physically interact and under normal conditions, are associated with the ER membrane. Overexpression of Alg13 leads to its cytosolic partitioning, as does reduction of Alg14 levels. Concomitant Alg14 overproduction suppresses this cytosolic partitioning of Alg13, demonstrating that Alg14 is both necessary and sufficient for the ER localization of Alg13. Further evidence for the functional relevance of this interaction comes from our demonstration that the human ALG13 and ALG14 orthologues fail to pair with their yeast partners, but when co-expressed in yeast can functionally complement the loss of either ALG13 or ALG14. These results demonstrate that this novel UDP-GlcNAc transferase is a unique eukaryotic ER glycosyltransferase that is comprised of at least two functional polypeptides, one that functions in catalysis and the other as a membrane anchor.

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Cullen, Paul J., Janet Schultz, Joe Horecka, Brian J. Stevenson, Yoshifumi Jigami, and George F. Sprague. "Defects in Protein Glycosylation Cause SHO1-Dependent Activation of a STE12 Signaling Pathway in Yeast." Genetics 155, no. 3 (July 1, 2000): 1005–18. http://dx.doi.org/10.1093/genetics/155.3.1005.

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Abstract In haploid Saccharomyces cerevisiae, mating occurs by activation of the pheromone response pathway. A genetic selection for mutants that activate this pathway uncovered a class of mutants defective in cell wall integrity. Partial loss-of-function alleles of PGI1, PMI40, PSA1, DPM1, ALG1, MNN10, SPT14, and OCH1, genes required for mannose utilization and protein glycosylation, activated a pheromone-response-pathway-dependent reporter (FUS1) in cells lacking a basal signal (ste4). Pathway activation was suppressed by the addition of mannose to hexose isomerase mutants pgi1-101 and pmi40-101, which bypassed the requirement for mannose biosynthesis in these mutants. Pathway activation was also suppressed in dpm1-101 mutants by plasmids that contained RER2 or PSA1, which produce the substrates for Dpm1. Activation of FUS1 transcription in the mannose utilization/protein glycosylation mutants required some but not all proteins from three different signaling pathways: the pheromone response, invasive growth, and HOG pathways. We specifically suggest that a Sho1 → Ste20/Ste50 → Ste11 → Ste7 → Kss1 → Ste12 pathway is responsible for activation of FUS1 transcription in these mutants. Because loss of pheromone response pathway components leads to a synthetic growth defect in mannose utilization/protein glycosylation mutants, we suggest that the Sho1 → Ste12 pathway contributes to maintenance of cell wall integrity in vegetative cells.

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Lizewski, Stephen E., Derek S. Lundberg, and Michael J. Schurr. "The Transcriptional Regulator AlgR Is Essential for Pseudomonas aeruginosa Pathogenesis." Infection and Immunity 70, no. 11 (November 2002): 6083–93. http://dx.doi.org/10.1128/iai.70.11.6083-6093.2002.

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ABSTRACT Chronic Pseudomonas aeruginosa lung infection is the major cause of morbidity and mortality in cystic fibrosis (CF) patients. One P. aeruginosa virulence factor unique to CF isolates is overproduction of alginate, phenotypically termed mucoidy. Mucoidy is the result of increased transcription from the algD gene and is activated by the transcriptional regulator AlgR. Mutations in algR result in a nonmucoid phenotype and loss of twitching motility. Additionally, AlgR controls transcription of algC, encoding a dual-function enzyme necessary for both lipopolysaccharide (LPS) and alginate production. Therefore, to determine the effect of algR on P. aeruginosa virulence, an algR mutant was examined for sensitivity to reactive oxygen intermediates, killing by phagocytes, systemic virulence, and the ability to maintain a murine lung infection. We found that P. aeruginosa PAO700 (algR::Gmr) was less lethal than PAO1, as tested in an acute septicemia infection mouse model, and was cleared more efficiently in a mouse pneumonia model. Additionally, the algR mutant (PAO700) was more sensitive to hypochlorite. However, PAO700 was more resistant to hydrogen peroxide and killed less readily in an acellular myeloperoxidase assay than PAO1. There was little difference in killing between PAO1 and PAO700 with macrophage-like J774 cells and human polymorhonuclear leukocytes. Two-dimensional gel analysis of P. aeruginosa algR mutant and wild-type protein extracts revealed 47 differentially regulated proteins, suggesting that AlgR plays both a positive role and a negative role in gene expression. Together, these results imply that AlgR is necessary for virulence and regulates genes in addition to the genes associated with alginate and LPS production and pilus function.

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Leech, Andrew J., April Sprinkle, Lynn Wood, Daniel J. Wozniak, and Dennis E. Ohman. "The NtrC Family Regulator AlgB, Which Controls Alginate Biosynthesis in Mucoid Pseudomonas aeruginosa, Binds Directly to the algD Promoter." Journal of Bacteriology 190, no. 2 (November 2, 2007): 581–89. http://dx.doi.org/10.1128/jb.01307-07.

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ABSTRACT Alginate production in mucoid (MucA-defective) Pseudomonas aeruginosa is dependent upon several transcriptional regulators, including AlgB, a two-component response regulator belonging to the NtrC family. This role of AlgB was apparently independent of its sensor kinase, KinB, and even the N-terminal phosphorylation domain of AlgB was dispensable for alginate biosynthetic gene (i.e., algD operon) activation. However, it remained unclear whether AlgB stimulated algD transcription directly or indirectly. In this study, microarray analyses were used to examine a set of potential AlgB-dependent, KinB-independent genes in a PAO1 mucA background that overlapped with genes induced by d-cycloserine, which is known to activate algD expression. This set contained only the algD operon plus one other gene that was shown to be uninvolved in alginate production. This suggested that AlgB promotes alginate production by directly binding to the algD promoter (PalgD). Chromosome immunoprecipitation revealed that AlgB bound in vivo to PalgD but did not bind when AlgB had an R442E substitution that disrupted the DNA binding domain. AlgB also showed binding to PalgD fragments in an electrophoretic mobility shift assay at pH 4.5 but not at pH 8.0. A direct systematic evolution of ligands by exponential enrichment approach showed AlgB binding to a 50-bp fragment located at bp −224 to −274 relative to the start of PalgD transcription. Thus, AlgB belongs to a subclass of NtrC family proteins that can activate promoters which utilize a sigma factor other than σ54, in this case to stimulate transcription from the σ22-dependent PalgD promoter.

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Ore B., Yerald, E. Renzo Pichilingue L, and Ana C. Valderrama Negrón. "EXTRACCIÓN Y CARACTERIZACIÓN DEL ALGINATO DE SODIO DE LA MACROALGA Macrocystis pyrifera." Revista de la Sociedad Química del Perú 86, no. 3 (September 30, 2020): 276–87. http://dx.doi.org/10.37761/rsqp.v86i3.300.

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En el presente trabajo se propuso un proceso de extracción de alginato de sodio, el cual fue obtenido a partir de la macroalga parda Macrocystis pyrifera recolectada en La Punta- Callao. El proceso de extracción presentó un rendimiento del 12 % y el alginato obtenido fue caracterizado mediante las técnicas de IR-TF y RMN 13C en estado sólido, el cual fue comparado con un alginato comercial. Se ha llevado a cabo la evaluación de la presencia de bloques manurónicos y gulurónicos IR-TF, mediante el uso de la 2da derivada obteniendo señales características a 894 cm-1 para C1-H α–L–gulurónico del alginato extraído de la macroalga Macrocystis pyrifera (AlgM) y a 885 cm-1 para la región anomérica C1-H del β–D– manurónico para el alginato comercial de Sigma Aldrich (AlgC). Asimismo, se asignaron señales características para el espectro del alga a 902 cm-1 y a 812 cm-1 correspondiente a vibraciones de los bloques α–L–gulurónico. Mediante 13C RMN en estado sólido se obtuvo un pico característico a 102,4 ppm para AlgM asociado al carbono anomérico C1-H α–L– gulurónico, mientras que en AlgC se visualizaron dos picos a 101,8 ppm y a 99,8 ppm asignados a C1-H α–L–gulurónico y C1-H β–D–manurónico, respectivamente, indicando así la presencia tanto de bloques G y bloques M en el alginato comercial.

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Fakhr, Mohamed K., Alejandro Peñaloza-Vázquez, Ananda M. Chakrabarty, and Carol L. Bender. "Regulation of Alginate Biosynthesis inPseudomonas syringae pv. syringae." Journal of Bacteriology 181, no. 11 (June 1, 1999): 3478–85. http://dx.doi.org/10.1128/jb.181.11.3478-3485.1999.

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ABSTRACT Both Pseudomonas aeruginosa and the phytopathogenP. syringae produce the exopolysaccharide alginate. However, the environmental signals that trigger alginate gene expression in P. syringae are different from those inP. aeruginosa with copper being a major signal in P. syringae. In P. aeruginosa, the alternate sigma factor encoded by algT (ς22) and the response regulator AlgR1 are required for transcription of algD, a gene which encodes a key enzyme in the alginate biosynthetic pathway. In the present study, we cloned and characterized the gene encoding AlgR1 from P. syringae. The deduced amino acid sequence of AlgR1 from P. syringae showed 86% identity to its P. aeruginosa counterpart. Sequence analysis of the region flankingalgR1 in P. syringae revealed the presence ofargH, algZ, and hemC in an arrangement virtually identical to that reported in P. aeruginosa. An algR1 mutant, P. syringaeFF5.32, was defective in alginate production but could be complemented when algR1 was expressed in trans. ThealgD promoter region in P. syringae(PsalgD) was also characterized and shown to diverge significantly from the algD promoter in P. aeruginosa. Unlike P. aeruginosa, algR1was not required for the transcription of algD in P. syringae, and PsalgD lacked the consensus sequence recognized by AlgR1. However, both the algD andalgR1 upstream regions in P. syringae contained the consensus sequence recognized by ς22, suggesting thatalgT is required for transcription of both genes.

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Ma, Sheng, Uma Selvaraj, Dennis E. Ohman, Ryan Quarless, Daniel J. Hassett, and Daniel J. Wozniak. "Phosphorylation-Independent Activity of the Response Regulators AlgB and AlgR in Promoting Alginate Biosynthesis in MucoidPseudomonas aeruginosa." Journal of Bacteriology 180, no. 4 (February 15, 1998): 956–68. http://dx.doi.org/10.1128/jb.180.4.956-968.1998.

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ABSTRACT Overproduction of the capsular polysaccharide alginate appears to confer a selective advantage for Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. The regulators AlgB and AlgR, which are both required as positive activators in alginate overproduction, have homology with the regulator class of two-component environmental responsive proteins which coordinate gene expression through signal transduction mechanisms. Signal transduction in this class of proteins generally occurs via autophosphorylation of the sensor kinase protein and phosphotransfer from the sensor to a conserved aspartate residue, which is present in the amino terminus of the response regulator. Recently,kinB was identified downstream of algB and was shown to encode the cognate histidine protein kinase that efficiently phosphorylates AlgB. However, we show here that a null mutation inkinB in a mucoid cystic fibrosis isolate, P. aeruginosa FRD1, did not block alginate production. The role of the conserved aspartate residue in the phosphorylation of AlgB was examined. The predicted phosphorylation site of AlgB (D59) was mutated to asparagine (N), and a derivative of an AlgB lacking the entire amino-terminal phosphorylation domain (AlgBΔ1-145) was constructed. A hexahistidine tag was included at the amino terminus of the wild-type (H-AlgB), H-AlgBΔ1-145, and mutant (H-AlgB.59N) AlgB proteins. These derivatives were purified by Ni2+affinity chromatography and examined for in vitro phosphorylation by the purified sensor kinase protein, KinB. The results indicated that while KinB efficiently phosphorylated H-AlgB, no phosphorylation of H-AlgBΔ1-145 or H-AlgB.D59N was apparent. An allelic exchange system was developed to transfer mutantalgB alleles onto the chromosome of a P. aeruginosa algB mutant to examine the effect on alginate production. Despite the defect in AlgB phosphorylation,P. aeruginosa strains expressing AlgB.D59N or H-AlgBΔ1-145 remained mucoid. The roles of the conserved aspartate residues in the phosphorylation of AlgR were also examined. As seen with AlgB, mutations in the predicted phosphorylation site of AlgR (AlgR.D54N and AlgR.D85N) did not affect alginate production. These results indicate that in vivo phosphorylation of AlgB and AlgR are not required for their roles in alginate production. Thus, the mechanism by which these response regulators activate alginate genes in mucoid P. aeruginosa appears not to be mediated by conventional phosphorylation-dependent signal transduction.

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Shibata, Toshiyuki, Reona Fujii, Hideo Miyake, Reiji Tanaka, Tetsushi Mori, Mami Takahashi, Toshiyuki Takagi, Hiroyuki Yoshikawa, Kouichi Kuroda, and Mitsuyoshi Ueda. "Development of an Analysis Method for 4-Deoxy-l-erythro-5-hexoseulose Uronic Acid by LC/ESI/MS with Selected Ion Monitoring." Natural Product Communications 12, no. 6 (June 2017): 1934578X1701200. http://dx.doi.org/10.1177/1934578x1701200627.

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This study describes a simple and rapid analytical quantitative method for measuring 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH) using liquid chromatography-electrospray ionization-mass spectrometry (LC/ESI/MS). For a chromatographic condition, Shodex IC NI-424 column (4.6 mm i.d. x 100 mm, 5 μm) for anion analysis and an isocratic elution of 40 mM ammonium formate buffer including 0.1% formic acid (pH 3.75) at a flow rate of 0.5 mL/min was used. The column temperature was set to 40°C. In the analysis of DEH produced by exo-type alginate lyase (AlyFRB) from Falsirhodobacter sp. alg1, a peak was detected with a retention time of 3.207 min. The prepared calibration curves for DEH analysis using the selected ion monitoring (SIM) mode of a mass spectrometer revealed a good linear relationship (correlation factor: 0.9998) within the test range (0.1–100 μg/mL). The limits of detection (S/N = 3) and quantification (S/N = 10) for DEH in SIM analysis were 0.008 and 0.027 μg/mL, respectively. Using the developed condition of LC/ESI/MS analysis, separation and detection of alginate unsaturated oligosaccharides were also tested. In an analysis time of about 13 min, this method was able to separate and detect an alginate unsaturated disaccharide, a trisaccharide, and a tetrasaccaride produced by poly(β-D-mannuronate) lyase, respectively. The analysis method established in this study will contribute to the quantitative and qualitative analysis of DEH, and the activity measurement of exo-type alginate lyase.

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Núñez, Cinthia, Soledad Moreno, Gloria Soberón-Chávez, and Guadalupe Espín. "The Azotobacter vinelandii Response Regulator AlgR Is Essential for Cyst Formation." Journal of Bacteriology 181, no. 1 (January 1, 1999): 141–48. http://dx.doi.org/10.1128/jb.181.1.141-148.1999.

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ABSTRACT Azotobacter vinelandii produces the exopolysaccharide alginate, which is essential for the encystment process. InPseudomonas aeruginosa, as well as in A. vinelandii, the ςE factor encoded byalgU is required for transcription of algD, which encodes a key enzyme of the alginate biosynthetic pathway. TheP. aeruginosa response regulator AlgR activates transcription of algD. fimS, located upstreamalgR, is proposed to encode the AlgR cognate sensor kinase. We have cloned and characterized the A. vinelandii algRgene; the deduced amino acid sequence of the protein encoded by this gene shows 79% identity with its P. aeruginosa homolog. Sequence analysis around the algR gene revealed the absence of a fimS homolog. Inactivation of A. vinelandii algR diminished alginate production by 50%, but did not affectalgD transcription, and completely impaired the capacity to form mature cysts. Electron microscopy of the cyst structures formed by the algR mutant revealed that the encystment process is blocked at the step of exine formation. The transcriptional regulation of the A. vinelandii algR gene and the role of AlgR in alginate production differ significantly from those of its P. aeruginosa counterparts. These differences could be due to the fact that in A. vinelandii, alginate plays a role in encystment, a function not found in P. aeruginosa.

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Woolwine, Samuel C., and Daniel J. Wozniak. "Identification of an Escherichia coli pepA Homolog and Its Involvement in Suppression of thealgB Phenotype in Mucoid Pseudomonas aeruginosa." Journal of Bacteriology 181, no. 1 (January 1, 1999): 107–16. http://dx.doi.org/10.1128/jb.181.1.107-116.1999.

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ABSTRACT Strains of Pseudomonas aeruginosa isolated from the respiratory tracts of patients with cystic fibrosis often display a mucoid morphology due to high levels of expression of the exopolysaccharide alginate. The response regulator AlgB is required for full transcription of the alginate biosynthetic operon. Repeated attempts to demonstrate a direct interaction between AlgB and the promoter region of algD, the first gene in the alginate operon, have thus far been unsuccessful. The possibility that AlgB exerts its effect on algD indirectly exists. To identify putative genes under the control of AlgB which affect algDtranscription, transposon mutagenesis of nonmucoid algBderivatives of the mucoid strain FRD1 was employed. Of approximately 3,000 transposon mutants screened, 6 were found to display phenotypes which were mucoid relative to the phenotype of the parentalalgB strain. The phenotypes of these mutants ranged from being only slightly mucoid to being indistinguishable from that of the original FRD1 strain. One of the particularly mucoid transposon mutants was chosen for further study. This strain was found to be disrupted in a previously uncharacterized open reading frame with 56% amino acid identity to PepA of Escherichia coli. PepA is classified as a leucine aminopeptidase, and homologs have been detected in a number of bacterial, plant, and animal species. This novel gene has been designated phpA (P. aeruginosa homolog ofpepA). The insertional inactivation of phpA was found to correlate with the mucoid phenotype and an increase inalgD transcription in the algB strain. Expression of phpA from an ectopic chromosomal locus compensated for the transposon insertion in the native phpAgene, restoring algD transcription to levels similar to those observed in the parental algB strain. WhilephpA expression did not appear to be under the control of AlgB at the transcriptional level, this study demonstrates that loss ofphpA in an algB genetic background had a positive effect on alginate expression and, more specifically, on transcription of the alginate biosynthetic operon.

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Douthit, Stephanie A., Mensur Dlakic, Dennis E. Ohman, and Michael J. Franklin. "Epimerase Active Domain of Pseudomonas aeruginosa AlgG, a Protein That Contains a Right-Handed β-Helix." Journal of Bacteriology 187, no. 13 (July 1, 2005): 4573–83. http://dx.doi.org/10.1128/jb.187.13.4573-4583.2005.

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ABSTRACT The polysaccharide alginate forms a protective capsule for Pseudomonas aeruginosa during chronic pulmonary infections. The structure of alginate, a linear polymer of β1-4-linked O-acetylated d-mannuronate (M) and l-guluronate (G), is important for its activity as a virulence factor. Alginate structure is mediated by AlgG, a periplasmic C-5 mannuronan epimerase. AlgG also plays a role in protecting alginate from degradation by the periplasmic alginate lyase AlgL. Here, we show that the C-terminal region of AlgG contains a right-handed β-helix (RHβH) fold, characteristic of proteins with the carbohydrate-binding and sugar hydrolase (CASH) domain. When modeled based on pectate lyase C of Erwinia chrysanthemi, the RHβH of AlgG has a long shallow groove that may accommodate alginate, similar to protein/polysaccharide interactions of other CASH domain proteins. The shallow groove contains a 324-DPHD motif that is conserved among AlgG and the extracellular mannuronan epimerases of Azotobacter vinelandii. Point mutations in this motif disrupt mannuronan epimerase activity but have no effect on alginate secretion. The D324A mutation has a dominant negative phenotype, suggesting that the shallow groove in AlgG contains the catalytic face for epimerization. Other conserved motifs of the epimerases, 361-NNRSYEN and 381-NLVAYN, are predicted to lie on the opposite side of the RHβH from the catalytic center. Point mutations N362A, N367A, and V383A result in proteins that do not protect alginate from AlgL, suggesting that these mutant proteins are not properly folded or not inserted into the alginate biosynthetic scaffold. These motifs are likely involved in asparagine and hydrophobic stacking, required for structural integrity of RHβH proteins, rather than for mannuronan catalysis. The results suggest that the AlgG RHβH protects alginate from degradation by AlgL by channeling the alginate polymer through the proposed alginate biosynthetic scaffold while epimerizing approximately every second d-mannuronate residue to l-guluronate along the epimerase catalytic face.

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Killoran, Maureen, Dan Kolenick, and Thomas Gelbman. "Navigating Murky Waters: Emerging Trends in Aboriginal Consultation and Project Approval." Alberta Law Review 52, no. 2 (January 5, 2015): 207. http://dx.doi.org/10.29173/alr1.

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This article surveys the most significant recent Canadian decisions engaging the Crown’s duty to consult Aboriginal peoples in the context of natural resource and infrastructure developments and explores the following themes. First, project opponents are initiating legal challenges early and often. Second, recent decisions have affirmed the principle that the duty to consult can be fulfilled through an existing regulatory review process. Third, the jurisdiction of certain administrative tribunals to determine the adequacy of consultation and other constitutional questions remains unsettled. Fourth, Aboriginal groups continue to launch novel challenges, seeking to expand the scope of the duty to consult, often beyond the specific Crown conduct being challenged. Fifth, courts are increasingly intolerant of abuses of process, particularly where litigants fail to seek proper recourse for their grievances. Finally, project proponents are seeking recourse against the Crown in cases where it has failed to adequately consult or accommodate.

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Rehman, Zahid U., and Bernd H. A. Rehm. "Dual Roles of Pseudomonas aeruginosa AlgE in Secretion of the Virulence Factor Alginate and Formation of the Secretion Complex." Applied and Environmental Microbiology 79, no. 6 (January 18, 2013): 2002–11. http://dx.doi.org/10.1128/aem.03960-12.

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ABSTRACTAlgE is a monomeric 18-stranded β-barrel protein required for secretion of the extracellular polysaccharide alginate inPseudomonas aeruginosa. To assess the molecular mechanism of alginate secretion, AlgE was subjected to site-specific and FLAG epitope insertion mutagenesis. Except for β-strands 6 and 10, epitope insertions into the transmembrane β-strands abolished localization of AlgE to the outer membrane. Interestingly, an epitope insertion into β-strand 10 produced alginate and was only detectable in outer membranes isolated from cells grown on solid media. The deletion of nine C-terminal amino acid residues destabilized AlgE. Replacement of amino acids that constitute the highly electropositive pore constriction showed that individual amino acid residues have a specific function in alginate secretion. Two of the triple mutants (K47E+R353A+R459E and R74E+R362A+R459E) severely reduced alginate production. Mutual stability analysis using thealgEdeletion mutant PDO300ΔalgE(miniCTX) showed the periplasmic alginate biosynthesis proteins AlgK and AlgX were completely destabilized, while the copy number of the inner membrane c-di-GMP receptor Alg44 was reduced. Chromosomal integration ofalgErestored AlgK, AlgX, and Alg44, providing evidence for a multiprotein complex that spans the cell envelope. Periplasmic turn 4 of AlgE was identified as an important region for maintaining the stability of the putative multiprotein complex.

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Tan, Jingquan, Sarah L. Rouse, Dianfan Li, Valerie E. Pye, Lutz Vogeley, Alette R. Brinth, Toufic El Arnaout, et al. "A conformational landscape for alginate secretion across the outer membrane ofPseudomonas aeruginosa." Acta Crystallographica Section D Biological Crystallography 70, no. 8 (July 25, 2014): 2054–68. http://dx.doi.org/10.1107/s1399004714001850.

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The exopolysaccharide alginate is an important component of biofilms produced byPseudomonas aeruginosa, a major pathogen that contributes to the demise of cystic fibrosis patients. Alginate exits the cellviathe outer membrane porin AlgE. X-ray structures of several AlgE crystal forms are reported here. Whilst all share a common β-barrel constitution, they differ in the degree to which loops L2 and T8 are ordered. L2 and T8 have been identified as an extracellular gate (E-gate) and a periplasmic gate (P-gate), respectively, that reside on either side of an alginate-selectivity pore located midway through AlgE. Passage of alginate across the membrane is proposed to be regulated by the sequential opening and closing of the two gates. In one crystal form, the selectivity pore contains a bound citrate. Because citrate mimics the uronate monomers of alginate, its location is taken to highlight a route through AlgE taken by alginate as it crosses the pore. Docking and molecular-dynamics simulations support and extend the proposed transport mechanism. Specifically, the P-gate and E-gate are flexible and move between open and closed states. Citrate can leave the selectivity pore bidirectionally. Alginate docks stably in a linear conformation through the open pore. To translate across the pore, a force is required that presumably is provided by the alginate-synthesis machinery. Accessing the open pore is facilitated by complex formation between AlgE and the periplasmic protein AlgK. Alginate can thread through a continuous pore in the complex, suggesting that AlgK pre-orients newly synthesized exopolysaccharide for delivery to AlgE.

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Wozniak, D. J., and D. E. Ohman. "Transcriptional analysis of the Pseudomonas aeruginosa genes algR, algB, and algD reveals a hierarchy of alginate gene expression which is modulated by algT." Journal of Bacteriology 176, no. 19 (1994): 6007–14. http://dx.doi.org/10.1128/jb.176.19.6007-6014.1994.

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Whitchurch, Cynthia B., Tatiana E. Erova, Jacqui A. Emery, Jennifer L. Sargent, Jonathan M. Harris, Annalese B. T. Semmler, Michael D. Young, John S. Mattick, and Daniel J. Wozniak. "Phosphorylation of the Pseudomonas aeruginosa Response Regulator AlgR Is Essential for Type IV Fimbria-Mediated Twitching Motility." Journal of Bacteriology 184, no. 16 (August 15, 2002): 4544–54. http://dx.doi.org/10.1128/jb.184.16.4544-4554.2002.

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ABSTRACT The response regulator AlgR is required for both alginate biosynthesis and type IV fimbria-mediated twitching motility in Pseudomonas aeruginosa. In this study, the roles of AlgR signal transduction and phosphorylation in twitching motility and biofilm formation were examined. The predicted phosphorylation site of AlgR (aspartate 54) and a second aspartate (aspartate 85) in the receiver domain of AlgR were mutated to asparagine, and mutant algR alleles were introduced into the chromosome of P. aeruginosa strains PAK and PAO1. Assays of these mutants demonstrated that aspartate 54 but not aspartate 85 of AlgR is required for twitching motility and biofilm initiation. However, strains expressing AlgR D85N were found to be hyperfimbriate, indicating that both aspartate 54 and aspartate 85 are involved in fimbrial biogenesis and function. algD mutants were observed to have wild-type twitching motility, indicating that AlgR control of twitching motility is not mediated via its role in the control of alginate biosynthesis. In vitro phosphorylation assays showed that AlgR D54N is not phosphorylated by the enteric histidine kinase CheA. These findings indicate that phosphorylation of AlgR most likely occurs at aspartate 54 and that aspartate 54 and aspartate 85 of AlgR are required for the control of the molecular events governing fimbrial biogenesis, twitching motility, and biofilm formation in P. aeruginosa.

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Garrett, Edward S., Demetra Perlegas, and Daniel J. Wozniak. "Negative Control of Flagellum Synthesis in Pseudomonas aeruginosa Is Modulated by the Alternative Sigma Factor AlgT (AlgU)." Journal of Bacteriology 181, no. 23 (December 1, 1999): 7401–4. http://dx.doi.org/10.1128/jb.181.23.7401-7404.1999.

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ABSTRACT Many respiratory isolates of Pseudomonas aeruginosafrom cystic fibrosis patients are mucoid (alginate producing) yet lack flagella. It was hypothesized that an alginate regulator inhibits flagellar gene expression. Mutations in algB,algR, and algT resulted in nonmucoid derivatives, yet algT mutants expressed flagella. AlgT-dependent control of flagellum synthesis occurred through inhibition of fliC but not rpoN transcription.

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Damron, F. Heath, Dongru Qiu, and Hongwei D. Yu. "The Pseudomonas aeruginosa Sensor Kinase KinB Negatively Controls Alginate Production through AlgW-Dependent MucA Proteolysis." Journal of Bacteriology 191, no. 7 (January 23, 2009): 2285–95. http://dx.doi.org/10.1128/jb.01490-08.

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ABSTRACT Mucoidy, or overproduction of the exopolysaccharide known as alginate, in Pseudomonas aeruginosa is a poor prognosticator for lung infections in cystic fibrosis. Mutation of the anti-σ factor MucA is a well-accepted mechanism for mucoid conversion. However, certain clinical mucoid strains of P. aeruginosa have a wild-type (wt) mucA. Here, we describe a loss-of-function mutation in kinB that causes overproduction of alginate in the wt mucA strain PAO1. KinB is the cognate histidine kinase for the transcriptional activator AlgB. Increased alginate production due to inactivation of kinB was correlated with high expression at the alginate-related promoters P algU and P algD . Deletion of alternative σ factor RpoN (σ54) or the response regulator AlgB in kinB mutants decreased alginate production to wt nonmucoid levels. Mucoidy was restored in the kinB algB double mutant by expression of wt AlgB or phosphorylation-defective AlgB.D59N, indicating that phosphorylation of AlgB was not required for alginate overproduction when kinB was inactivated. The inactivation of the DegS-like protease AlgW in the kinB mutant caused loss of alginate production and an accumulation of the hemagglutinin (HA)-tagged MucA. Furthermore, we observed that the kinB mutation increased the rate of HA-MucA degradation. Our results also indicate that AlgW-mediated MucA degradation required algB and rpoN in the kinB mutant. Collectively, these studies indicate that KinB is a negative regulator of alginate production in wt mucA strain PAO1.

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Lipke, Stephan. "REALISMO MACABRO EN LA NOVELA NOLI ME TANGERE DE JOSÉ RIZAL A LA LUZ DEL POEMA ALMAS MUERTAS DE NIKOLAI GOGOL." Acta Literaria, no. 61 (June 2020): 39–55. http://dx.doi.org/10.29393/al61-9rmsl10009.

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García-Reyes, David. "LAS NARRACIONES GRÁFICAS DE JULIO CORTÁZAR: HIBRIDACIONES Y EXPRESIONES CRÍTICAS." Acta Literaria, no. 61 (June 2020): 15–37. http://dx.doi.org/10.29393/al61-8ngdg10008.

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Journal articles on the topic 'ALG1'

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