scholarly journals Analysis of epitope distribution of arabinogalactan protein-extensins in pea (Pisum Sativum) nodules of wild-type and mutants impaired in infection thread growth

2019 ◽  
Vol 17 (3) ◽  
pp. 5-12
Author(s):  
Anna V. Tsyganova ◽  
Nicholas J. Brewin ◽  
Viktor E. Tsyganov
Keyword(s):  
Mutant Line ◽  
Arabinogalactan Protein ◽  
Infection Thread ◽  
Immunogold Electron Microscopy ◽  
Bacterial Cells ◽  
Wild Type ◽  
Infection Threads ◽  
The Matrix ◽  
Pea Mutants ◽  
High Level

Background. During the colonization of root and nodule tissues of legumes by rhizobia, bacterial cells are immersed in a plant extracellular matrix which includes arabinogalactan protein-extensins (AGPE). Materials and methods. Immunogold electron microscopy with monoclonal antibodies MAC204 and MAC236 was used to analyse the distribution and abundance of epitopes of AGPE in wild-type and symbiotically defective pea mutants. Results. In the nodules of the wild-type line SGE, both AGPE epitopes were detected to the same extent in the matrix of infection threads and infection droplets. In the nodules of the mutant line SGEFix-1 (sym40), the level of labelling by MAC204 was significantly higher than with SGE in both infection threads and infection droplets, but the level of labelling by MAC236 was only increased in the infection droplets. In the mutant line SGEFix-2 (sym33-3), a relatively high level of both epitopes was observed among all analysed genotypes. The double mutant line RBT3 (sym33-3, sym40) showed an intermediate level of labelling for both epitopes in infection threads compared with the parental mutants. In SGEFix-1, an abnormal distribution of both epitopes was observed in the intercellular space matrix. The MAC204 epitope was found in the cell walls of SGEFix-1 and in the infection thread walls of SGEFix-2, whereas in RBT3 this epitope was detected in both types of walls. Conclusions. The sym33-3 and sym40 mutations have different effects on the accumulation of AGPE epitopes recognised by MAC204 and MAC236. This indicates that both the Sym33 and the Sym40 genes affect the composition of AGPE in the matrix of infection threads and infection droplets.

scholarly journals Role of Cellulose Fibrils and Exopolysaccharides of Rhizobium leguminosarum in Attachment to and Infection of Vicia sativa Root Hairs

2005 ◽  
Vol 18 (6) ◽  
pp. 533-538 ◽  
Author(s):  
M. C. Laus ◽  
A. A. N. van Brussel ◽  
J. W. Kijne
Keyword(s):  
Root Hair ◽  
Rhizobium Leguminosarum ◽  
Developmental Stages ◽  
Cortical Cell ◽  
Root Hairs ◽  
Infection Thread ◽  
Vicia Sativa ◽  
Wild Type ◽  
Infection Threads ◽  
Cellulose Fibrils

Infection and subsequent nodulation of legume host plants by the root nodule symbiote Rhizobium leguminosarum usually require attachment of the bacteria to root-hair tips. Bacterial cellulose fibrils have been shown to be involved in this attachment process but appeared not to be essential for successful nodulation. Detailed analysis of Vicia sativa root-hair infection by wild-type Rhizobium leguminosarum RBL5523 and its cellulose fibril-deficient celE mutant showed that wild-type bacteria infected elongated growing root hairs, whereas cellulose-deficient bacteria infected young emerging root hairs. Exopolysaccharide-deficient strains that retained the ability to produce cellulose fibrils could also infect elongated root hairs but infection thread colonization was defective. Cellulose-mediated agglutination of these bacteria in the root-hair curl appeared to prevent entry into the induced infection thread. Infection experiments with V. sativa roots and an extracellular polysaccharide (EPS)- and cellulose-deficient double mutant showed that cellulose-mediated agglutination of the EPS-deficient bacteria in the infection thread was now abolished and that infection thread colonization was partially restored. Interestingly, in this case, infection threads were initiated in root hairs that originated from the cortical cell layers of the root and not in epidermal root hairs. Apparently, surface polysaccharides of R. leguminosarum, such as cellulose fibrils, are determining factors for infection of different developmental stages of root hairs.

Distribution of legume arabinogalactan protein-extensin (AGPE) glycoproteins in symbiotically defective pea mutants with abnormal infection threads

2009 ◽  
Vol 3 (1) ◽  
pp. 93-102 ◽  
Author(s):  
A. V. Tsyganova ◽  
V. E. Tsyganov ◽  
K. C. Findlay ◽  
A. Y. Borisov ◽  
I. A. Tikhonovich ◽  
...  
Keyword(s):  
Arabinogalactan Protein ◽  
Infection Threads ◽  
Pea Mutants

scholarly journals Hampered motility promotes the evolution of wrinkly phenotype in Bacillus subtilis

2018 ◽  
Author(s):  
Anne Richter ◽  
Theresa Hölscher ◽  
Patrick Pausch ◽  
Tim Sehrt ◽  
Franziska Brockhaus ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Dna Interaction ◽  
Bacterial Cells ◽  
Wild Type ◽  
Motile Cells ◽  
The Matrix ◽  
In The Wild ◽  
Selection For ◽  
Air Liquid Interface ◽  
Dna Binding Properties

SummarySelection for a certain trait in microbes depends on the genetic background of the strain and the selection pressure of the environmental conditions acting on the cells. In contrast to the sessile state in the biofilm, various bacterial cells employ flagellum-dependent motility under planktonic conditions suggesting that the two phenotypes are mutually exclusive. However, flagellum dependent motility facilitates the prompt establishment of floating biofilms on the air-medium interface, called pellicles. Previously, pellicles of B. subtilis were shown to be preferably established by motile cells, causing a reduced fitness of non-motile derivatives in the presence of the wild type strain. Here, we show that lack of fully assembled flagella promotes the evolution of matrix overproducers that can be distinguished by the characteristic wrinkled colony morphotype. The wrinkly phenotype is associated with amino acid substitutions in the master repressor of biofilm-related genes, SinR. By analyzing one of the mutations, we show that it alters the tetramerization and DNA binding properties of SinR, allowing an increased expression of the operon responsible for exopolysaccharide production. Finally, we demonstrate that the wrinkly phenotype is advantageous when cells lack flagella, but not in the wild type background.Graphical AbstractAbbreviated SummaryDuring biofilm establishment at the air-liquid interface, Bacillus subtilis evolves matrix overproducers with a wrinkly colony phenotype (WS). This is caused by mutations in the regulator SinR which alter its dimerization and DNA interaction properties. The matrix overproducers appear mostly in a non-motile mutant where they possess a competitive advantage for biofilm formation, which is not present in the wild type background.

Structure of the exudate gum from Meryta sinclairii

2020 ◽  
Author(s):  
Ian Sims ◽  
Richard Furneaux
Keyword(s):  
Average Molecular Weight ◽  
Gum Arabic ◽  
Arabinogalactan Protein ◽  
Weight Average Molecular Weight ◽  
1H And 13C Nmr ◽  
One Dimensional ◽  
Linkage Analyses ◽  
Yariv Reagent ◽  
Native Tree ◽  
High Level

A gum that exudes from the wounded trunk of the New Zealand native tree Meryta sinclairii has been isolated. The gum was completely precipitated by the β-glucosyl Yariv reagent and was thus determined to be an arabinogalactan-protein (AGP). It contained >95% w/w carbohydrate and only 2% w/w protein with a high level of hydroxyproline. SEC-MALLS showed that the gum had a weight-average molecular weight of 4.45×106Da compared with 6.02×105Da for gum arabic. Constituent sugar and linkage analyses were consistent with polymers comprised of a highly branched backbone of 1,3-linked galactopyranosyl (Galp) residues, with side-chains made up of arabinofuranose- (Araf) containing oligosaccharides, terminated variously by rhamnopyranosyl (Rhap), arabinopyranosyl (Arap), Galp and glucuronopyranosyl (GlcpA) residues. Analysis by one-dimensional and two-dimensional 1H and 13C NMR experiments confirmed the linkage analyses. The structure of the gum is discussed in comparison with the structure of gum arabic and other AGPs. © 2003 Elsevier Science Ltd. All rights reserved.

Toxic Effect of 2-ethyl (bicyclo[2.2.1] heptane) on Bacterial Cells

2019 ◽  
Vol 35 (6) ◽  
pp. 67-72 ◽  
Author(s):  
I.V. Manukhov ◽  
L.S. Yaguzhinsky ◽  
M.V. Bermeshev ◽  
M.A. Zisman ◽  
V.G. Pevgov ◽  
...  
Keyword(s):  
Toxic Effect ◽  
Atmospheric Oxygen ◽  
Inducible Promoter ◽  
Oxygen Species ◽  
Bacterial Cells ◽  
Unique Identifier ◽  
E Coli ◽  
Lux Biosensors ◽  
High Level ◽  
Ministry Of Higher Education

Toxic effect of 2-ethylnorbornane (2-ethyl(bicyclo[2.2.1]heptane) (EBH)) on bacteria has been studied using the E. coli pRecA-lux and E. coli pKatG- lux cells as lux-biosensors. It was shown that the addition of EBH to the incubation medium leads to death and growth retardation, high level oxidative stress and DNA damage in E. coli cells. It is assumed that the oxidation of EBH with atmospheric oxygen causes the formation of reactive oxygen species in the medium, which makes a major contribution to the toxicity of this substance. biosensor, luciferase, bioluminescence, inducible promoter, PrecA, PkatG The authors are grateful to Stanislav Filippovich Chalkin for the development of interdisciplinary ties in the scientific community. The work was financially supported by the Ministry of Higher Education and Science of Russia (Project Unique Identifier RFMEFI60417X0181, Agreement No. 14.604.21.0181 of 26.09.2017).

scholarly journals Mutations in fbiD (Rv2983) as a Novel Determinant of Resistance to Pretomanid and Delamanid in Mycobacterium tuberculosis

2020 ◽  
Vol 65 (1) ◽  
pp. e01948-20
Author(s):  
Dalin Rifat ◽  
Si-Yang Li ◽  
Thomas Ioerger ◽  
Keshav Shah ◽  
Jean-Philippe Lanoix ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Clinical Evidence ◽  
Clinical Samples ◽  
Loss Of Function ◽  
Wild Type ◽  
Content Type ◽  
Solid Media ◽  
High Level ◽  
Level Resistance

ABSTRACTThe nitroimidazole prodrugs delamanid and pretomanid comprise one of only two new antimicrobial classes approved to treat tuberculosis (TB) in 50 years. Prior in vitro studies suggest a relatively low barrier to nitroimidazole resistance in Mycobacterium tuberculosis, but clinical evidence is limited to date. We selected pretomanid-resistant M. tuberculosis mutants in two mouse models of TB using a range of pretomanid doses. The frequency of spontaneous resistance was approximately 10−5 CFU. Whole-genome sequencing of 161 resistant isolates from 47 mice revealed 99 unique mutations, of which 91% occurred in 1 of 5 genes previously associated with nitroimidazole activation and resistance, namely, fbiC (56%), fbiA (15%), ddn (12%), fgd (4%), and fbiB (4%). Nearly all mutations were unique to a single mouse and not previously identified. The remaining 9% of resistant mutants harbored mutations in Rv2983 (fbiD), a gene not previously associated with nitroimidazole resistance but recently shown to be a guanylyltransferase necessary for cofactor F420 synthesis. Most mutants exhibited high-level resistance to pretomanid and delamanid, although Rv2983 and fbiB mutants exhibited high-level pretomanid resistance but relatively small changes in delamanid susceptibility. Complementing an Rv2983 mutant with wild-type Rv2983 restored susceptibility to pretomanid and delamanid. By quantifying intracellular F420 and its precursor Fo in overexpressing and loss-of-function mutants, we provide further evidence that Rv2983 is necessary for F420 biosynthesis. Finally, Rv2983 mutants and other F420H2-deficient mutants displayed hypersusceptibility to some antibiotics and to concentrations of malachite green found in solid media used to isolate and propagate mycobacteria from clinical samples.

scholarly journals Allelic Exchange and Mutant Selection Demonstrate that Common Clinical embCAB Gene Mutations Only Modestly Increase Resistance to Ethambutol in Mycobacterium tuberculosis

2009 ◽  
Vol 54 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Hassan Safi ◽  
Robert D. Fleischmann ◽  
Scott N. Peterson ◽  
Marcus B. Jones ◽  
Behnam Jarrahi ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
In Vitro Selection ◽  
Gene Mutations ◽  
Wild Type ◽  
Mutant Selection ◽  
Preferential Growth ◽  
Allelic Exchange ◽  
High Level ◽  
Isogenic Mutants

ABSTRACT Mutations within codon 306 of the Mycobacterium tuberculosis embB gene modestly increase ethambutol (EMB) MICs. To identify other causes of EMB resistance and to identify causes of high-level resistance, we generated EMB-resistant M. tuberculosis isolates in vitro and performed allelic exchange studies of embB codon 406 (embB406) and embB497 mutations. In vitro selection produced mutations already identified clinically in embB306, embB397, embB497, embB1024, and embC13, which result in EMB MICs of 8 or 14 μg/ml, 5 μg/ml, 12 μg/ml, 3 μg/ml, and 4 μg/ml, respectively, and mutations at embB320, embB324, and embB445, which have not been identified in clinical M. tuberculosis isolates and which result in EMB MICs of 8 μg/ml, 8 μg/ml, and 2 to 8 μg/ml, respectively. To definitively identify the effect of the common clinical embB497 and embB406 mutations on EMB susceptibility, we created a series of isogenic mutants, exchanging the wild-type embB497 CAG codon in EMB-susceptible M. tuberculosis strain 210 for the embB497 CGG codon and the wild-type embB406 GGC codon for either the embB406 GCC, embB406 TGC, embB406 TCC, or embB406 GAC codon. These new mutants showed 6-fold and 3- to 3.5-fold increases in the EMB MICs, respectively. In contrast to the embB306 mutants, the isogenic embB497 and embB406 mutants did not have preferential growth in the presence of isoniazid or rifampin (rifampicin) at their MICs. These results demonstrate that individual embCAB mutations confer low to moderate increases in EMB MICs. Discrepancies between the EMB MICs of laboratory mutants and clinical M. tuberculosis strains with identical mutations suggest that clinical EMB resistance is multigenic and that high-level EMB resistance requires mutations in currently unknown loci.

scholarly journals Transcriptome Analysis Provides Insights into the Mechanism of Astaxanthin Enrichment in a Mutant of the Ridgetail White Prawn Exopalaemon carinicauda

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 618
Author(s):  
Yue Jin ◽  
Shihao Li ◽  
Yang Yu ◽  
Chengsong Zhang ◽  
Xiaojun Zhang ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Underlying Mechanism ◽  
Biological Processes ◽  
Wild Type ◽  
Expression Levels ◽  
In The Wild ◽  
Cuticle Proteins ◽  
Apolipoprotein D ◽  
High Level ◽  
Lower Expression

A mutant of the ridgetail white prawn, which exhibited rare orange-red body color with a higher level of free astaxanthin (ASTX) concentration than that in the wild-type prawn, was obtained in our lab. In order to understand the underlying mechanism for the existence of a high level of free astaxanthin, transcriptome analysis was performed to identify the differentially expressed genes (DEGs) between the mutant and wild-type prawns. A total of 78,224 unigenes were obtained, and 1863 were identified as DEGs, in which 902 unigenes showed higher expression levels, while 961 unigenes presented lower expression levels in the mutant in comparison with the wild-type prawns. Based on Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes analysis, as well as further investigation of annotated DEGs, we found that the biological processes related to astaxanthin binding, transport, and metabolism presented significant differences between the mutant and the wild-type prawns. Some genes related to these processes, including crustacyanin, apolipoprotein D (ApoD), cathepsin, and cuticle proteins, were identified as DEGs between the two types of prawns. These data may provide important information for us to understand the molecular mechanism of the existence of a high level of free astaxanthin in the prawn.

Flavonoids and UV Photoprotection in Arabidopsis Mutants

2001 ◽  
Vol 56 (9-10) ◽  
pp. 745-754 ◽  
Author(s):  
Ken G Ryan ◽  
Ewald E Swinny ◽  
Chris Winefield ◽  
Kenneth R Markham
Keyword(s):  
Crucial Role ◽  
Hydroxycinnamic Acid ◽  
Ultraviolet B ◽  
Uvb Radiation ◽  
Wild Type ◽  
Hydroxycinnamic Acid Derivatives ◽  
Quercetin Glycosides ◽  
Kaempferol Glycosides ◽  
Low Levels ◽  
High Level

AbstractWild-type Arabidopsis L. leaves exposed to low ultraviolet-B (U V B ) conditions contained predominantly kaempferol glycosides, with low levels of quercetin glycosides. The flavonoid level doubled on treatment with UVB and an increase in the ratio of quercetin: kaempferol was observed. These results suggest that flavonols protect Arabidopsis plants from UVB damage, and indicate that the flavonoid 3’-hydroxylase (F3’H) enzyme, which converts dihydrokaempferol to dihydroquercetin, may play a crucial role. The tt7 mutant lacks this gene and, after treatment with sub-ambient UVB, contained kaempferol glycosides exclusively, to a level of total flavonols similar to that in wild-type Arabidopsis. Total flavonols after enhanced UVB treatment were higher in tt7 than in similarly treated wild-type plants, and only kaempferol glycosides were detected. Despite this high level, tt7 plants were less tolerant of UVB radiation than wild-type plants. These observations suggests that kaempferol is a less effective photoprotectant than quercetin. The chalcone isomerase (CHI) mutant (tt5) surprisingly did not accumulate naringenin chalcone, and this suggests that the mutation may not be restricted to the CHI gene alone. The concentration of hydroxycinnamic acid derivatives did not change with UVB treatment in most varieties indicating that their role in UV photoprotection may be subordinate to that of the flavonoids.

scholarly journals High level expression of transgenes by use of 5^|^#8242;-untranslated region of the Arabidopsis thaliana arabinogalactan-protein 21 gene in dicotyledons

2012 ◽  
Vol 29 (3) ◽  
pp. 319-322 ◽  
Author(s):  
Takeshi Matsui ◽  
Hideyuki Matsuura ◽  
Kazutoshi Sawada ◽  
Eiji Takita ◽  
Satoko Kinjo ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Untranslated Region ◽  
Arabinogalactan Protein ◽  
High Level Expression ◽  
High Level
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