scholarly journals Role of an In Planta-Expressed Xylanase of Xanthomonas oryzae pv. oryzae in Promoting Virulence on Rice

2005 ◽  
Vol 18 (8) ◽  
pp. 830-837 ◽  
Author(s):  
R. Rajeshwari ◽  
Gopaljee Jha ◽  
Ramesh V. Sonti
Keyword(s):  
Xylanase Activity ◽  
Xanthomonas Oryzae ◽  
Mass Spectrometry Analysis ◽  
Type Ii Secretion ◽  
In Planta ◽  
Gene Encoding ◽  
Spectrometry Analysis ◽  
Type Ii Secretion System ◽  
Biochemical Assays ◽  
Serious Disease

Xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight, a serious disease of rice. We demonstrated earlier that the type II secretion system (T2S) is important for virulence of X. oryzae pv. oryzae and that several proteins, including a xylanase, are secreted through this system. In this study, the xynB gene encoding for the secreted xylanase was cloned as a 6.9-kb Eco RI fragment (pRR7) that also included a paralog called xynA. As in X. oryzae pv. oryzae, xynA and xynB are adjacent to each other in X. axonopodis pv. citri, whereas only the xynA homolog is present in X. campestris pv. campestris. Mutations in xynB but not xynA affect secreted xylanase activity. Western blot analysis using anti-XynB antibodies on exudates from infected rice leaves indicated that this xylanase is expressed during in planta growth. Another T2S-secreted protein was identified to be a lipase/esterase (LipA) based on the sequence tags obtained by tandem mass spectrometry analysis and biochemical assays. Mutations in either xynB or lipA partially affected virulence. However, a lipA-xynB double mutant was significantly reduced for virulence, and the pRR7 clone containing an intact xynB gene could complement the virulence-deficient phenotype of the lipA-xynB mutant. Our results suggest that there is functional redundancy among the T2S secreted proteins of X. oryzae pv. oryzae in promoting virulence on rice.

Feline Spongy Encephalopathy With a Mutation in the ASPA Gene

2021 ◽  
pp. 030098582110021
Author(s):  
Yuta Takaichi ◽  
James K. Chambers ◽  
Moeko Shiroma-Kohyama ◽  
Makoto Haritani ◽  
Yumi Une ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Canavan Disease ◽  
Mass Spectrometry Analysis ◽  
Intensity Change ◽  
Gas Chromatography Mass Spectrometry ◽  
Clinical Genetic ◽  
Gene Encoding ◽  
Spongy Degeneration ◽  
Spectrometry Analysis ◽  
Dense Granules

Canavan disease is an autosomal recessive leukodystrophy caused by mutations in the gene encoding aspartoacylase (ASPA), which hydrolyses N-acetylaspartate (NAA) to acetate and aspartate. A similar feline neurodegenerative disease associated with a mutation in the ASPA gene is reported herein. Comprehensive clinical, genetic, and pathological analyses were performed on 4 affected cats. Gait disturbance and head tremors initially appeared at 1 to 19 months of age. These cats eventually exhibited dysstasia and seizures and died at 7 to 53 months of age. Magnetic resonance imaging of the brain revealed diffuse symmetrical intensity change of the cerebral cortex, brainstem, and cerebellum. Gas chromatography–mass spectrometry analysis of urine showed significant excretion of NAA. Genetic analysis of the 4 affected cats identified a missense mutation (c.859G>C) in exon 6 of the ASPA gene, which was not detected in 4 neurologically intact cats examined as controls. Postmortem analysis revealed vacuolar changes predominantly distributed in the gray matter of the cerebrum and brain stem as well as in the cerebellar Purkinje cell layer. Immunohistochemically, these vacuoles were surrounded by neurofilaments and sometimes contained MBP- and Olig2-positive cells. Ultrastructurally, a large number of intracytoplasmic vacuoles containing mitochondria and electron-dense granules were detected in the cerebral cortex. All 4 cats were diagnosed as spongy encephalopathy with a mutation in the ASPA gene, a syndrome analogous to human Canavan disease. The histopathological findings suggest that feline ASPA deficiency induces intracytoplasmic edema in neurons and oligodendrocytes, resulting in spongy degeneration of the central nervous system.

scholarly journals Morphological, Pathogenic and Toxigenic Variability in the Rice Sheath Rot Pathogen Sarocladium Oryzae

Toxins ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 109 ◽  
Author(s):  
Kaat José Peeters ◽  
Ashley Haeck ◽  
Lies Harinck ◽  
Oluwatoyin Oluwakemi Afolabi ◽  
Kristof Demeestere ◽  
...  
Keyword(s):  
Acid Production ◽  
High Resolution Mass Spectrometry ◽  
Toxin Production ◽  
Mass Spectrometry Analysis ◽  
In Planta ◽  
Spectrometry Analysis ◽  
Helvolic Acid ◽  
Phylogenetic Lineages ◽  
Sheath Rot

Sheath rot is an emerging rice disease that leads to considerable yield losses. The main causal agent is the fungus Sarocladium oryzae. This pathogen is known to produce the toxins cerulenin and helvolic acid, but their role in pathogenicity has not been clearly established. S. oryzea isolates from different rice-producing regions can be grouped into three phylogenetic lineages. When grown in vitro, isolates from these lineages differed in growth rate, colour and in the ability to form sectors. A diverse selection of isolates from Rwanda and Nigeria, representing these lineages, were used to further study their pathogenicity and toxin production. Liquid chromatography high-resolution mass spectrometry analysis was used to measure cerulenin and helvolic acid production in vitro and in planta. The three lineages clearly differed in pathogenicity on the japonica cultivar Kitaake. Isolates from the least pathogenic lineage produced the highest levels of cerulenin in vitro. Helvolic acid production was not correlated with the lineage. Sectorisation was observed in isolates from the two least pathogenic lineages and resulted in a loss of helvolic acid production. In planta, only the production of helvolic acid, but not of cerulenin, correlated strongly with disease severity. The most pathogenic isolates all belonged to one lineage. They were phenotypically stable, shown by the lack of sectorisation, and therefore maintained high helvolic acid production in planta.

scholarly journals β-N-Acetylglucosamine (O-GlcNAc) Is a Novel Regulator of Mitosis-specific Phosphorylations on Histone H3

2012 ◽  
Vol 287 (15) ◽  
pp. 12195-12203 ◽  
Author(s):  
Jerry J. Fong ◽  
Brenda L. Nguyen ◽  
Robert Bridger ◽  
Estela E. Medrano ◽  
Lance Wells ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Histone H3 ◽  
Mass Spectrometry Analysis ◽  
Post Translational Modification ◽  
Cycle Progression ◽  
Spectrometry Analysis ◽  
Biochemical Assays ◽  
M Phase ◽  
Nucleocytoplasmic Proteins

O-Linked β-N-acetylglucosamine, or O-GlcNAc, is a dynamic post-translational modification that cycles on and off serine and threonine residues of nucleocytoplasmic proteins. The O-GlcNAc modification shares a complex relationship with phosphorylation, as both modifications are capable of mutually inhibiting the occupation of each other on the same or nearby amino acid residue. In addition to diabetes, cancer, and neurodegenerative diseases, O-GlcNAc appears to play a significant role in cell growth and cell cycle progression, although the precise mechanisms are still not well understood. A recent study also found that all four core nucleosomal histones (H2A, H2B, H3, and H4) are modified with O-GlcNAc, although no specific sites on H3 were reported. Here, we describe that histone H3, a protein highly phosphorylated during mitosis, is modified with O-GlcNAc. Several biochemical assays were used to validate that H3 is modified with O-GlcNAc. Mass spectrometry analysis identified threonine 32 as a novel O-GlcNAc site. O-GlcNAc was detected at higher levels on H3 during interphase than mitosis, which inversely correlated with phosphorylation. Furthermore, increased O-GlcNAcylation was observed to reduce mitosis-specific phosphorylation at serine 10, serine 28, and threonine 32. Finally, inhibiting OGA, the enzyme responsible for removing O-GlcNAc, hindered the transition from G2 to M phase of the cell cycle, displaying a phenotype similar to preventing mitosis-specific phosphorylation on H3. Taken together, these data indicate that O-GlcNAcylation regulates mitosis-specific phosphorylations on H3, providing a mechanistic switch that orchestrates the G2-M transition of the cell cycle.

scholarly journals Novel Insights into Tat Pathway in Xanthomonas oryzae pv. oryzae Stress Adaption and Virulence: Identification and Characterization of Tat-Dependent Translocation Proteins

2017 ◽  
Vol 107 (9) ◽  
pp. 1011-1021 ◽  
Author(s):  
Guichun Wu ◽  
Panpan Su ◽  
Bo Wang ◽  
Yuqiang Zhang ◽  
Guoliang Qian ◽  
...  
Keyword(s):  
Underlying Mechanism ◽  
Vital Role ◽  
Xanthomonas Oryzae ◽  
Phenotypic Characterization ◽  
In Planta ◽  
Bioinformatics Analyses ◽  
Swarming Motility ◽  
Twin Arginine Translocation ◽  
Tat Pathway ◽  
Serious Disease

Xanthomonas oryzae pv. oryzae, an economically important bacterium, causes a serious disease in rice production worldwide called bacterial leaf blight. How X. oryzae pv. oryzae infects rice and causes symptoms remains incompletely understood. Our earlier works demonstrated that the twin-arginine translocation (Tat) pathway plays an vital role in X. oryzae pv. oryzae fitness and virulence but the underlying mechanism is unknown. In this study, we used strain PXO99A as a working model, and identified 15 potential Tat-dependent translocation proteins (TDTP) by using comparative proteomics and bioinformatics analyses. Combining systematic mutagenesis, phenotypic characterization, and gene expression, we found that multiple TDTP play key roles in X. oryzae pv. oryzae adaption or virulence. In particular, four TDTP (PXO_02203, PXO_03477, PXO_02523, and PXO_02951) were involved in virulence, three TDTP (PXO_02203, PXO_03477, and PXO_02523) contributed to colonization in planta, one TDTP (PXO_02671) had a key role in attachment to leaf surface, four TDTP (PXO_02523, PXO_02951, PXO_03132, and PXO_03841) were involved in tolerance to multiple stresses, and two TDTP (PXO_02523 and PXO_02671) were required for full swarming motility. These findings suggest that multiple TDTP may have differential contributions to involvement of the Tat pathway in X. oryzae pv. oryzae adaption, physiology, and pathogenicity.

scholarly journals Dysglycaemia and South Asian ethnicity: a proteomic discovery and confirmation analysis highlights differences in ZAG

2020 ◽  
Vol 11 (4) ◽  
pp. 259-268
Author(s):  
Harriet M. Pearsey ◽  
Joseph Henson ◽  
Jack A. Sargeant ◽  
David Webb ◽  
Jason M. R. Gill ◽  
...  
Keyword(s):  
Glycaemic Control ◽  
South Asian ◽  
Linear Models ◽  
Univariate Analysis ◽  
Density Lipoprotein ◽  
Mass Spectrometry Analysis ◽  
Asian Ethnicity ◽  
Spectrometry Analysis ◽  
Biochemical Assays ◽  
South Asian Ethnicity

Abstract Aims To (1) explore and verify differences in the plasma proteome of white European (WE) and South Asian (SA) adults with normal glycaemic control (NGC) or non-diabetic hyperglycaemia (NDH) and to (2) validate these findings using a separate WE and SA cohort at a high risk of NDH. Methods Mass spectrometry analysis was performed on fasted samples from 72 WE or SA men with NGC or NDH. These results were verified using specific biochemical assays and validated by repeating the analysis in an additional cohort of 30 WE and 30 SA adults. Proteomic results were analysed using independent samples t test and univariate analysis. The targeted assay results were analysed using generalised linear models with adjustment for appropriate covariates including age, BMI, fasting plasma glucose, high-density lipoprotein-cholesterol, triglycerides and sex. Results Only zinc-alpha-2-glycoprotein (ZAG) significantly differed between both ethnicities and glycaemic control groups. ZAG-specific biochemical assays verified the lower circulating ZAG in SAs (41.09 versus 37.07 (mg L−1); p = 0.014), but not the difference between NGC and NDH groups (p = 0.539). Validation of the ethnicity difference in a separate cohort confirmed that, after adjustment for covariates, ZAG was lower in SAs (p = 0.018). There was no association between ZAG and glycaemic control in the validation cohort. Conclusions Our analyses identified that ZAG is lower in SAs compared to WEs, but its difference between glycaemic control statuses was uncertain. Further research is needed to establish whether lower ZAG in SAs is associated with, or prognostic of, health outcomes, particularly regarding the risk of dysglycaemia.

scholarly journals Ferredoxin-mediated reduction of 2-nitrothiophene inhibits photosynthesis: mechanism and herbicidal potential

2020 ◽  
Vol 477 (6) ◽  
pp. 1149-1158
Author(s):  
Yehouda Marcus ◽  
Michael Gurevitz
Keyword(s):  
Electron Transfer ◽  
Anaerobic Bacteria ◽  
Degradation Pathway ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
In Planta ◽  
Iron Sulfur Cluster ◽  
Spectrometry Analysis ◽  
Amino Derivatives ◽  
A Site

Searching for compounds that inhibit the growth of photosynthetic organisms highlighted a prominent effect at micromolar concentrations of the nitroheteroaromatic thioether, 2-nitrothiophene, applied in the light. Since similar effects were reminiscent to those obtained also by radicals produced under excessive illumination or by herbicides, and in light of its redox potential, we suspected that 2-nitrothiophene was reduced by ferredoxin, a major reducing compound in the light. In silico examination using docking and tunneling computing algorithms of the putative interaction between 2-nitrothiophene and cyanobacterial ferredoxin has suggested a site of interaction enabling robust electron transfer from the iron–sulfur cluster of ferredoxin to the nitro group of 2-nitrothiophene. ESR and oximetry analyses of cyanobacterial cells (Anabaena PCC7120) treated with 50 μM 2-nitrothiophene under illumination revealed accumulation of oxygen radicals and peroxides. Gas chromatography mass spectrometry analysis of 2-nitrothiophene-treated cells identified cytotoxic nitroso and non-toxic amino derivatives. These products of the degradation pathway of 2-nitrohiophene, which initializes with a single electron transfer that forms a short-live anion radical, are then decomposed to nitrate and thiophene, and may be further reduced to a nitroso hydroxylamine and amino derivatives. This mechanism of toxicity is similar to that of nitroimidazoles (e.g. ornidazole and metronidazole) reduced by ferredoxin in anaerobic bacteria and protozoa, but differs from that of ornidazole in planta.

scholarly journals Role of the FeoB Protein and Siderophore in Promoting Virulence of Xanthomonas oryzae pv. oryzae on Rice

2010 ◽  
Vol 192 (12) ◽  
pp. 3187-3203 ◽  
Author(s):  
Alok Pandey ◽  
Ramesh V. Sonti
Keyword(s):  
Gene Cluster ◽  
Functional Characterization ◽  
Biosynthetic Gene Cluster ◽  
Xanthomonas Oryzae ◽  
In Planta ◽  
Growth Deficiency ◽  
Constitutive Production ◽  
Serious Disease

ABSTRACT Xanthomonas oryzae pv. oryzae causes bacterial blight, a serious disease of rice. Our analysis revealed that the X. oryzae pv. oryzae genome encodes genes responsible for iron uptake through FeoB (homolog of the major bacterial ferrous iron transporter) and a siderophore. A mutation in the X. oryzae pv. oryzae feoB gene causes severe virulence deficiency, growth deficiency in iron-limiting medium, and constitutive production of a siderophore. We identified an iron regulated xss gene cluster, in which xssABCDE ( X anthomonas siderophore synthesis) and xsuA ( X anthomonas siderophore utilization) genes encode proteins involved in biosynthesis and utilization of X. oryzae pv. oryzae siderophore. Mutations in the xssA, xssB, and xssE genes cause siderophore deficiency and growth restriction under iron-limiting conditions but are virulence proficient. An xsuA mutant displayed impairment in utilization of native siderophore, suggesting that XsuA acts as a specific receptor for a ferric-siderophore complex. Histochemical and fluorimetric assays with gusA fusions indicate that, during in planta growth, the feoB gene is expressed and that the xss operon is not expressed. This study represents the first report describing a role for feoB in virulence of any plant-pathogenic bacterium and the first functional characterization of a siderophore-biosynthetic gene cluster in any xanthomonad.

scholarly journals Arabidopsis Lectin Receptor Kinases LecRK-IX.1 and LecRK-IX.2 Are Functional Analogs in Regulating Phytophthora Resistance and Plant Cell Death

2015 ◽  
Vol 28 (9) ◽  
pp. 1032-1048 ◽  
Author(s):  
Yan Wang ◽  
Jan H. G. Cordewener ◽  
Antoine H. P. America ◽  
Weixing Shan ◽  
Klaas Bouwmeester ◽  
...  
Keyword(s):  
Cell Death ◽  
Abc Transporter ◽  
Mitogen Activated Protein Kinase ◽  
Mass Spectrometry Analysis ◽  
In Planta ◽  
Lectin Domain ◽  
Spectrometry Analysis ◽  
Lectin Receptor ◽  
Receptor Kinases ◽  
Phytophthora Resistance

L-type lectin receptor kinases (LecRK) are potential immune receptors. Here, we characterized two closely-related Arabidopsis LecRK, LecRK-IX.1 and LecRK-IX.2, of which T-DNA insertion mutants showed compromised resistance to Phytophthora brassicae and Phytophthora capsici, with double mutants showing additive susceptibility. Overexpression of LecRK-IX.1 or LecRK-IX.2 in Arabidopsis and transient expression in Nicotiana benthamiana increased Phytophthora resistance but also induced cell death. Phytophthora resistance required both the lectin domain and kinase activity, but for cell death, the lectin domain was not needed. Silencing of the two closely related mitogen-activated protein kinase genes NbSIPK and NbNTF4 in N. benthamiana completely abolished LecRK-IX.1-induced cell death but not Phytophthora resistance. Liquid chromatography-mass spectrometry analysis of protein complexes coimmunoprecipitated in planta with LecRK-IX.1 or LecRK-IX.2 as bait, resulted in the identification of the N. benthamiana ABC transporter NbPDR1 as a potential interactor of both LecRK. The closest homolog of NbPDR1 in Arabidopsis is ABCG40, and coimmunoprecipitation experiments showed that ABCG40 associates with LecRK-IX.1 and LecRK-IX.2 in planta. Similar to the LecRK mutants, ABCG40 mutants showed compromised Phytophthora resistance. This study shows that LecRK-IX.1 and LecRK-IX.2 are Phytophthora resistance components that function independent of each other and independent of the cell-death phenotype. They both interact with the same ABC transporter, suggesting that they exploit similar signal transduction pathways.

scholarly journals Analysis of diverse eukaryotes suggests the existence of an ancestral mitochondrial apparatus derived from the bacterial type II secretion system

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lenka Horváthová ◽  
Vojtěch Žárský ◽  
Tomáš Pánek ◽  
Romain Derelle ◽  
Jan Pyrih ◽  
...  
Keyword(s):  
Functional Data ◽  
Secretion System ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Type Ii Secretion System ◽  
Biochemical Assays ◽  
Functional Pathway ◽  
Bacterial Type ◽  
Different Parts

AbstractThe type 2 secretion system (T2SS) is present in some Gram-negative eubacteria and used to secrete proteins across the outer membrane. Here we report that certain representative heteroloboseans, jakobids, malawimonads and hemimastigotes unexpectedly possess homologues of core T2SS components. We show that at least some of them are present in mitochondria, and their behaviour in biochemical assays is consistent with the presence of a mitochondrial T2SS-derived system (miT2SS). We additionally identified 23 protein families co-occurring with miT2SS in eukaryotes. Seven of these proteins could be directly linked to the core miT2SS by functional data and/or sequence features, whereas others may represent different parts of a broader functional pathway, possibly also involving the peroxisome. Its distribution in eukaryotes and phylogenetic evidence together indicate that the miT2SS-centred pathway is an ancestral eukaryotic trait. Our findings thus have direct implications for the functional properties of the early mitochondrion.

scholarly journals Ancestral mitochondrial apparatus derived from the bacterial type II secretion system

2019 ◽  
Author(s):  
Lenka Horváthová ◽  
Vojtěch Žárský ◽  
Tomáš Pánek ◽  
Romain Derelle ◽  
Jan Pyrih ◽  
...  
Keyword(s):  
Functional Data ◽  
Secretion System ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Type Ii Secretion System ◽  
Biochemical Assays ◽  
Protein Secretion System ◽  
Functional Pathway ◽  
Bacterial Type

AbstractThe type 2 secretion system (T2SS) is present in some Gram-negative eubacteria and used to secrete proteins across the outer membrane. Here we report that certain representative heteroloboseans, jakobids, malawimonads and hemimastigotes unexpectedly possess homologues of core T2SS components. We show that at least some of them are present in mitochondria, and their behaviour in biochemical assays is consistent with the formation of a mitochondrial T2SS-derived protein secretion system (miT2SS). We additionally identified 23 protein families co-occurring with miT2SS in eukaryotes. Seven of these proteins could be directly linked to the core miT2SS by functional data and/or sequence features, whereas others may represent different parts of a broader functional pathway, possibly also involving the peroxisome. Its distribution in eukaryotes and phylogenetic evidence together indicate that the miT2SS-centred pathway is an ancestral eukaryotic trait. Our findings thus have direct implications for the functional properties of the early mitochondrion.

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