scholarly journals Analysis of Genomes Changes in Pseudomonas Chlororaphis Subsp. Aurantiaca Strains Producing Phenazines

2021 ◽  
Author(s):  
Anastasia I. Liaudanskaya ◽  
Natalia P. Maximova ◽  
Katsiaryna G. Verameyenka
Keyword(s):  
Mutant Strain ◽  
Phenylalanine Hydroxylase ◽  
Response Regulator ◽  
Trna Genes ◽  
Type I ◽  
Pseudomonas Chlororaphis ◽  
Wild Type ◽  
Mutant Proteins ◽  
Domain Structures ◽  
Genome Annotations

Abstract Genomes of three strains – phenazine producers – Pseudomonas chlororaphis subsp. aurantiaca (B-162 (wild-type), mutant strain B-162/255 and its derivatives B-162/17) were sequenced and compared. All genome annotations revealed 6347 CDS, 5 rRNA clusters (5S, 16S, 23S) and 59 tRNA genes. Comparison analysis of wild-type strain and B-162/255 mutant strain genomes allowed revealing 32 mutations. 19 new mutations were detected upon comparison of genomes strains B-162/255 and B-162/17. Further bioinformatics analysis allowed predicting mutant proteins` functions and secondary structures of five gene products, mutations in which might potentially have influence on phenazine synthesis and secretion in Pseudomonas bacteria. These genes are phenylalanine hydroxylase transcriptional activator PhhR, type I secretion system ATPase, transcriptional regulator MvaT, GacA response regulator and histidine kinase. Amino acid substitutions were located in domain structures of corresponding proteins.

scholarly journals Identification of the Missing trans-Acting Enoyl Reductase Required for Phthiocerol Dimycocerosate and Phenolglycolipid Biosynthesis in Mycobacterium tuberculosis

2007 ◽  
Vol 189 (13) ◽  
pp. 4597-4602 ◽  
Author(s):  
Roxane Siméone ◽  
Patricia Constant ◽  
Christophe Guilhot ◽  
Mamadou Daffé ◽  
Christian Chalut
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mutant Strain ◽  
Mycobacterium Bovis ◽  
Reductase Activity ◽  
Polyketide Synthases ◽  
Type I ◽  
Wild Type ◽  
Enoyl Reductase ◽  
Phthiocerol Dimycocerosates ◽  
Activity Domain

ABSTRACT Phthiocerol dimycocerosates (DIM) and phenolglycolipids (PGL) are functionally important surface-exposed lipids of Mycobacterium tuberculosis. Their biosynthesis involves the products of several genes clustered in a 70-kb region of the M. tuberculosis chromosome. Among these products is PpsD, one of the modular type I polyketide synthases responsible for the synthesis of the lipid core common to DIM and PGL. Bioinformatic analyses have suggested that this protein lacks a functional enoyl reductase activity domain required for the synthesis of these lipids. We have identified a gene, Rv2953, that putatively encodes an enoyl reductase. Mutation in Rv2953 prevents conventional DIM formation and leads to the accumulation of a novel DIM-like product. This product is unsaturated between C-4 and C-5 of phthiocerol. Consistently, complementation of the mutant with a functional pks15/1 gene from Mycobacterium bovis BCG resulted in the accumulation of an unsaturated PGL-like substance. When an intact Rv2953 gene was reintroduced into the mutant strain, the phenotype reverted to the wild type. These findings indicate that Rv2953 encodes a trans-acting enoyl reductase that acts with PpsD in phthiocerol and phenolphthiocerol biosynthesis.

Mutations responsible for MYH9-related thrombocytopenia impair SDF-1-driven migration of megakaryoblastic cells

2011 ◽  
Vol 106 (10) ◽  
pp. 693-704 ◽  
Author(s):  
Valeria Bozzi ◽  
Emanuele Panza ◽  
Serena Barozzi ◽  
Cristian Gruppi ◽  
Marco Seri ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Cell Types ◽  
Type I ◽  
Wild Type ◽  
Mutant Proteins ◽  
Wild Type Counterpart ◽  
Platelet Release ◽  
Myosin Iia ◽  
Different Cell Types

SummaryMYH9-related disease (MYH9-RD) is an autosomal-dominant thrombocytopenia caused by mutations in the gene for the heavy chain of nonmuscle myosin-IIA (NMMHC-IIA). Recent in vitro studies led to the hypothesis that thrombocytopenia of MYH9-RD derives from an ectopic platelet release by megakaryocytes in the osteoblastic areas of bone marrow (BM), which are enriched in type I collagen, rather than in vascular spaces. SDF-1-driven migration of megakaryocytes within BM to reach the vascular spaces is a key mechanism for platelet biogenesis. Since myosin-IIA is implicated in polarised migration of different cell types, we hypothesised that MYH9 mutations could interfere with this mechanism. We therefore investigated the SDF-1-driven migration of a megakaryoblastic cell line, Dami cells, on type I collagen or fibrinogen by a modified transwell assay. Inhibition of myosin-IIA ATPase activity suppressed the SDF-1-driven migration of Dami cells, while over-expression of NMMHC-IIA increased the efficiency of chemotaxis, indicat- ing a role for NMMHC-IIA in this mechanism. Transfection of cells with three MYH9 mutations frequently responsible for MYH9-RD (p.R702C, p.D1424H, or p.R1933X) resulted in a defective SDF-1-driven migration with respect to the wild-type counterpart and in increased cell spreading onto collagen. Analysis of differential localisation of wild-type and mutant proteins suggested that mutant NMMHC-IIAs had an impaired cytoplasmic re-organisation in functional cytoskeletal structures after cell adhesion to collagen. These findings support the hypothesis that a defect of SDF-1-driven migration of megakaryocytes induced by MYH9 mutations contributes to ectopic platelet release in the BM osteoblastic areas, resulting in ineffective platelet production.

scholarly journals Functional significance of lysine 1423 of neurofibromin and characterization of a second site suppressor which rescues mutations at this residue and suppresses RAS2Val-19-activated phenotypes.

1994 ◽  
Vol 14 (1) ◽  
pp. 815-821 ◽  
Author(s):  
P Poullet ◽  
B Lin ◽  
K Esson ◽  
F Tamanoi
Keyword(s):  
Amino Acids ◽  
Neurofibromatosis Type ◽  
Type I ◽  
Ras Proteins ◽  
Wild Type ◽  
Conserved Residues ◽  
Mutant Proteins ◽  
Quantitative Analyses ◽  
Intrinsic Gtpase Activity

Lysine 1423 of neurofibromin (neurofibromatosis type I gene product [NF1]) plays a crucial role in the function of NF1. Mutations of this lysine were detected in samples from a neurofibromatosis patient as well as from cancer patients. To further understand the significance of this residue, we have mutated it to all possible amino acids. Functional assays using yeast ira complementation have revealed that lysine is the only amino acid that produced functional NF1. Quantitative analyses of different mutant proteins have suggested that their GTPase-activating protein (GAP) activity is drastically reduced as a result of a decrease in their Ras affinity. Such a requirement for a specific residue is not observed in the case of other conserved residues within the GAP-related domain. We also report that another residue, phenylalanine 1434, plays an important role in NF1 function. This was first indicated by the finding that defective NF1s due to an alteration of lysine 1423 to other amino acids can be rescued by a second site intragenic mutation at residue 1434. The mutation partially restored GAP activity in the lysine mutant. When the mutation phenylalanine 1434 to serine was introduced into a wild-type NF1 protein, the resulting protein acquired the ability to suppress activated phenotypes of RAS2Val-19 cells. This suppression, however, does not involve Ras interaction, since the phenylalanine mutant does not stimulate the intrinsic GTPase activity of RAS2Val-19 protein and does not have an increased affinity for Ras proteins.

scholarly journals A Nonsense Mutation in agrA Accounts for the Defect in agr Expression and the Avirulence of Staphylococcus aureus 8325-4 traP::kan

2007 ◽  
Vol 75 (9) ◽  
pp. 4534-4540 ◽  
Author(s):  
Rajan P. Adhikari ◽  
Staffan Arvidson ◽  
Richard P. Novick
Keyword(s):  
Staphylococcus Aureus ◽  
Quorum Sensing ◽  
Mutant Strain ◽  
Nonsense Mutation ◽  
Stop Codon ◽  
Response Regulator ◽  
Wild Type ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Type Sequence

ABSTRACT TraP is a triply phosphorylated staphylococcal protein that has been hypothesized to be the mediator of a second Staphylococcus aureus quorum-sensing system, “SQS1,” that controls expression of the agr system and therefore is essential for the organism's virulence. This hypothesis was based on the loss of agr expression and virulence by a traP mutant of strain 8325-4 and was supported by full complementation of both phenotypic defects by the cloned traP gene in strain NB8 (Y. Gov, I. Borovok, M. Korem, V. K. Singh, R. K. Jayaswal, B. J. Wilkinson, S. M. Rich, and N. Balaban, J. Biol. Chem. 279:14665-14672, 2004), in which the wild-type traP gene was expressed in trans in the 8325-4 traP mutant. We initiated a study of the mechanism by which TraP activates agr and found that the traP mutant strain used for this and other recently published studies has a second mutation, an adventitious stop codon in the middle of agrA, the agr response regulator. The traP mutation, once separated from the agrA defect by outcrossing, had no effect on agr expression or virulence, indicating that the agrA defect accounts fully for the lack of agr expression and for the loss of virulence attributed to the traP mutation. In addition, DNA sequencing showed that the agrA gene in strain NB8 (Gov et al., J. Biol. Chem., 2004), in contrast to that in the agr-defective 8325-4 traP mutant strain, had the wild-type sequence; further, the traP mutation in that strain, when outcrossed, also had no effect on agr expression.

Functional significance of lysine 1423 of neurofibromin and characterization of a second site suppressor which rescues mutations at this residue and suppresses RAS2Val-19-activated phenotypes

1994 ◽  
Vol 14 (1) ◽  
pp. 815-821
Author(s):  
P Poullet ◽  
B Lin ◽  
K Esson ◽  
F Tamanoi
Keyword(s):  
Amino Acids ◽  
Neurofibromatosis Type ◽  
Type I ◽  
Ras Proteins ◽  
Wild Type ◽  
Conserved Residues ◽  
Mutant Proteins ◽  
Quantitative Analyses ◽  
Intrinsic Gtpase Activity

Lysine 1423 of neurofibromin (neurofibromatosis type I gene product [NF1]) plays a crucial role in the function of NF1. Mutations of this lysine were detected in samples from a neurofibromatosis patient as well as from cancer patients. To further understand the significance of this residue, we have mutated it to all possible amino acids. Functional assays using yeast ira complementation have revealed that lysine is the only amino acid that produced functional NF1. Quantitative analyses of different mutant proteins have suggested that their GTPase-activating protein (GAP) activity is drastically reduced as a result of a decrease in their Ras affinity. Such a requirement for a specific residue is not observed in the case of other conserved residues within the GAP-related domain. We also report that another residue, phenylalanine 1434, plays an important role in NF1 function. This was first indicated by the finding that defective NF1s due to an alteration of lysine 1423 to other amino acids can be rescued by a second site intragenic mutation at residue 1434. The mutation partially restored GAP activity in the lysine mutant. When the mutation phenylalanine 1434 to serine was introduced into a wild-type NF1 protein, the resulting protein acquired the ability to suppress activated phenotypes of RAS2Val-19 cells. This suppression, however, does not involve Ras interaction, since the phenylalanine mutant does not stimulate the intrinsic GTPase activity of RAS2Val-19 protein and does not have an increased affinity for Ras proteins.

scholarly journals RaxH/RaxR: A Two-Component Regulatory System in Xanthomonas oryzae pv. oryzae Required for AvrXa21 Activity

2004 ◽  
Vol 17 (6) ◽  
pp. 602-612 ◽  
Author(s):  
Saul Burdman ◽  
Yuwei Shen ◽  
Sang-Won Lee ◽  
Qinzhong Xue ◽  
Pamela Ronald
Keyword(s):  
Response Regulator ◽  
Sulfur Metabolism ◽  
Regulatory System ◽  
Xanthomonas Oryzae ◽  
Expression Vectors ◽  
Type I ◽  
Wild Type ◽  
Two Component ◽  
Genes Encoding ◽  
Null Mutants

Xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight, one of the most serious diseases in rice. X. oryzae pv. oryzae Philippine race 6 (PR6) strains are unable to establish infection in rice lines expressing the resistance gene Xa21. Although the pathogen-associated molecule that triggers the Xa21-mediated defense response (AvrXa21) is unknown, six rax (required for AvrXa21 activity) genes encoding proteins involved in sulfur metabolism and Type I secretion were recently identified. Here, we report on the identification of two additional rax genes, raxR and raxH, which encode a response regulator and a histidine protein kinase of two-component regulatory systems, respectively. Null mutants of PR6 strain PXO99 that are impaired in either raxR, raxH, or both cause lesions significantly longer and grow to significantly higher levels than does the wild-type strain in Xa21-rice leaves. Both raxR and raxH mutants are complemented to wild-type levels of AvrXa21 activity by introduction of expression vectors carrying raxR and raxH, respectively. These null mutants do not affect AvrXa7 and AvrXa10 activities, as observed in inoculation experiments with Xa7- and Xa10-rice lines. Western blot and raxR/gfp promoter-reporter analyses confirmed RaxR expression in X. oryzae pv. oryzae. The results of promoter-reporter studies also suggest that the previously identified raxSTAB operon is a target for RaxH/RaxR regulation. Characterization of the RaxH/RaxR system provides new opportunities for understanding the specificity of the X. oryzae pv. oryzae-Xa21 interaction and may contribute to the identification of AvrXa21.

Two Different UGT1A1 Mutations causing Crigler–Najjar Syndrome types I and II in an Iranian Family

2015 ◽  
Vol 24 (4) ◽  
pp. 523-526 ◽  
Author(s):  
Yoshihiro Maruo ◽  
Mahdiyeh Behnam ◽  
Shinichi Ikushiro ◽  
Sayuri Nakahara ◽  
Narges Nouri ◽  
...  
Keyword(s):  
Serum Bilirubin ◽  
Total Serum Bilirubin ◽  
Total Serum ◽  
Compound Heterozygous ◽  
Type I ◽  
Syndrome Type ◽  
Type Ii ◽  
Wild Type ◽  
Iranian Family ◽  
Udp Glucuronosyltransferase

Background: Crigler–Najjar syndrome type I (CN-1) and type II (CN-2) are rare hereditary unconjugated hyperbilirubinemia disorders. However, there have been no reports regarding the co-existence of CN-1 and CN-2 in one family. We experienced a case of an Iranian family that included members with either CN-1 or CN-2. Genetic analysis revealed a mutation in the bilirubin UDP-glucuronosyltransferase (UGT1A1) gene that resulted in residual enzymatic activity.Case report: The female proband developed severe hyperbilirubinemia [total serum bilirubin concentration (TB) = 34.8 mg/dL] with bilirubin encephalopathy (kernicterus) and died after liver transplantation. Her family history included a cousin with kernicterus (TB = 30.0 mg/dL) diagnosed as CN-1. Her great grandfather (TB unknown) and uncle (TB = 23.0 mg/dL) developed jaundice, but without any treatment, they remained healthy as CN-2. Results: The affected cousin was homozygous for a novel frameshift mutation (c.381insGG, p.C127WfsX23). The affected uncle was compound heterozygous for p.C127WfsX23 and p.V225G linked with A(TA)7TAA. p.V225G-UGT1A1 reduced glucuronidation activity to 60% of wild-type. Thus, linkage of A(TA)7TAA and p.V225G might reduce UGT1A1 activity to 18%–36 % of the wild-type. Conclusion: Genetic and in vitro expression analyses are useful for accurate genetic counseling for a family with a history of both CN-1 and CN-2. Abbreviations: CN-1: Crigler–Najjar syndrome type I; CN-2: Crigler–Najjar syndrome type II; GS: Gilbert syndrome; UGT1A1: bilirubin UDP-glucuronosyltransferase; WT: Wild type; TB: total serum bilirubin.

scholarly journals The role of Zur-regulated lipoprotein A in bacterial morphology, antimicrobial susceptibility, and production of outer membrane vesicles in Acinetobacter baumannii

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nayeong Kim ◽  
Hyo Jeong Kim ◽  
Man Hwan Oh ◽  
Se Yeon Kim ◽  
Mi Hyun Kim ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Mutant Strain ◽  
Antimicrobial Susceptibility ◽  
Type Strain ◽  
Wild Type Strain ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Wild Type ◽  
Bacterial Morphology

Abstract Background Zinc uptake-regulator (Zur)-regulated lipoprotein A (ZrlA) plays a role in bacterial fitness and overcoming antimicrobial exposure in Acinetobacter baumannii. This study further characterized the zrlA gene and its encoded protein and investigated the roles of the zrlA gene in bacterial morphology, antimicrobial susceptibility, and production of outer membrane vesicles (OMVs) in A. baumannii ATCC 17978. Results In silico and polymerase chain reaction analyses showed that the zrlA gene was conserved among A. baumannii strains with 97–100% sequence homology. Recombinant ZrlA protein exhibited a specific enzymatic activity of D-alanine-D-alanine carboxypeptidase. Wild-type A. baumannii exhibited more morphological heterogeneity than a ΔzrlA mutant strain during stationary phase. The ΔzrlA mutant strain was more susceptible to gentamicin than the wild-type strain. Sizes and protein profiles of OMVs were similar between the wild-type and ΔzrlA mutant strains, but the ΔzrlA mutant strain produced 9.7 times more OMV particles than the wild-type strain. OMVs from the ΔzrlA mutant were more cytotoxic in cultured epithelial cells than OMVs from the wild-type strain. Conclusions The present study demonstrated that A. baumannii ZrlA contributes to bacterial morphogenesis and antimicrobial resistance, but its deletion increases OMV production and OMV-mediated host cell cytotoxicity.

scholarly journals FixJ family regulator AcfR of Azorhizobium caulinodans is involved in symbiosis with the host plant

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wei Liu ◽  
Xue Bai ◽  
Yan Li ◽  
Haikun Zhang ◽  
Xiaoke Hu
Keyword(s):  
Signal Transduction ◽  
Host Plant ◽  
Type Strain ◽  
Wild Type Strain ◽  
Response Regulator ◽  
Azorhizobium Caulinodans ◽  
Wild Type ◽  
Response Regulators ◽  
Free Living ◽  
Two Component

Abstract Background A wide variety of bacterial adaptative responses to environmental conditions are mediated by signal transduction pathways. Two-component signal transduction systems are one of the predominant means used by bacteria to sense the signals of the host plant and adjust their interaction behaviour. A total of seven open reading frames have been identified as putative two-component response regulators in the gram-negative nitrogen-fixing bacteria Azorhizobium caulinodans ORS571. However, the biological functions of these response regulators in the symbiotic interactions between A. caulinodans ORS571 and the host plant Sesbania rostrata have not been elucidated to date. Results In this study, we identified and investigated a two-component response regulator, AcfR, with a phosphorylatable N-terminal REC (receiver) domain and a C-terminal HTH (helix-turn-helix) LuxR DNA-binding domain in A. caulinodans ORS571. Phylogenetic analysis showed that AcfR possessed close evolutionary relationships with NarL/FixJ family regulators. In addition, six histidine kinases containing HATPase_c and HisKA domains were predicted to interact with AcfR. Furthermore, the biological function of AcfR in free-living and symbiotic conditions was elucidated by comparing the wild-type strain and the ΔacfR mutant strain. In the free-living state, the cell motility behaviour and exopolysaccharide production of the ΔacfR mutant were significantly reduced compared to those of the wild-type strain. In the symbiotic state, the ΔacfR mutant showed a competitive nodule defect on the stems and roots of the host plant, suggesting that AcfR can provide A. caulinodans with an effective competitive ability for symbiotic nodulation. Conclusions Our results showed that AcfR, as a response regulator, regulates numerous phenotypes of A. caulinodans under the free-living conditions and in symbiosis with the host plant. The results of this study help to elucidate the involvement of a REC + HTH_LuxR two-component response regulator in the Rhizobium-host plant interaction.

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