scholarly journals Genotyping pathogenic strains of genus Xanthomonas causing bacterioses in a number of plants by DDSL technique

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Alexander Lazarev ◽  
Valery Terletskiy ◽  
Vladimir Chebotar

In the genus Xanthomonas, specialists consider a significant number of species and varieties (pathovars) of phytopathogenic bacteria that infect many agricultural and ornamental plants (about 400 species), which leads to serious economic losses. For the timely detection of these pathogens, accurate diagnosis is necessary, allowing correct and prompt identification. Molecular genetic methods are able to identify populations of Xanthomonas strains with a fairly complete characterization of their hereditary material. The proposed method of genotyping — double digest and selective label (DDSL) — is based on the use of two restriction endonucleases for the separation of bacterial genomic DNA. The DNA polymerase (Taq) present in the reaction mixture along with biotinylated deoxycytosine triphosphate (Bio–dCTP) allows for the visualization of DNA fragments. The tag only labels DNA fragments that have 3'-recessed ends formed by the first enzyme (BcuI). The second restriction endonuclease (Eco147I) produces blunt ends that are unable to incorporate the label. As a result, in the DDSL reaction, 20–50 clearly distinguishable DNA fragments are visualized on the filter. The number and distribution of fragments are characteristic for each bacterial strain of the genus Xanthomonas. Genotyping these microorganisms makes it possible to identify the specific profile of each strain, i.e., assign it a sort of “bar code” for individual specification. The strains of bacteria of the genus Xanthomonas, obtained from different species (tomato, radish, sorghum) are genetically separated from each other, showing a specific pattern in terms of the distribution of DNA fragments, despite the common geographical origin. A comparatively rare case of the identity of strains, despite their geographical and temporal unrelatedness and different cultures, has been recorded.

2012 ◽  
Vol 27 (3) ◽  
pp. 203-211 ◽  
Author(s):  
Snezana Milosevic ◽  
Aleksandar Cingel ◽  
Sladjana Jevremovic ◽  
Ivana Stankovic ◽  
Aleksandra Bulajic ◽  
...  

Viruses are responsible for numerous epidemics in different crops in all parts of the world. As a consequence of their presence great economic losses are being incurred. In addition to the development of sensitive techniques for detection, identification and characterization of viruses, substantial attention has also been paid to biotechnological methods for their elimination from plants. In this review article, the following biotechnological in vitro culture techniques for virus elimination from ornamental plants are presented: meristem culture, thermotherapy, chemotherapy, cryotherapy or a combination of these methods. The plant species, as well as the type of virus determine the choice of a most suitable method. The state of the art in investigation of virus elimination from Impatiens sp. in Serbia is summarized.


1982 ◽  
Vol 10 (1) ◽  
pp. 37-54 ◽  
Author(s):  
M. Kumar ◽  
C. W. Bert

Abstract Unidirectional cord-rubber specimens in the form of tensile coupons and sandwich beams were used. Using specimens with the cords oriented at 0°, 45°, and 90° to the loading direction and appropriate data reduction, we were able to obtain complete characterization for the in-plane stress-strain response of single-ply, unidirectional cord-rubber composites. All strains were measured by means of liquid mercury strain gages, for which the nonlinear strain response characteristic was obtained by calibration. Stress-strain data were obtained for the cases of both cord tension and cord compression. Materials investigated were aramid-rubber, polyester-rubber, and steel-rubber.


Author(s):  
G. Meneghesso ◽  
E. Zanoni ◽  
P. Colombo ◽  
M. Brambilla ◽  
R. Annunziata ◽  
...  

Abstract In this work, we present new results concerning electrostatic discharge (ESD) robustness of 0.6 μm CMOS structures. Devices have been tested according to both HBM and socketed CDM (sCDM) ESD test procedures. Test structures have been submitted to a complete characterization consisting in: 1) measurement of the tum-on time of the protection structures submitted to pulses with very fast rise times; 2) ESD stress test with the HBM and sCDM models; 3) failure analysis based on emission microscopy (EMMI) and Scanning Electron Microscopy (SEM).


2019 ◽  
Vol 125 (1) ◽  
pp. 10008 ◽  
Author(s):  
Bat-el Friedman ◽  
Atanu Rajak ◽  
Emanuele G. Dalla Torre

2019 ◽  
Vol 53 (5) ◽  
pp. 1763-1773
Author(s):  
Meziane Aider ◽  
Lamia Aoudia ◽  
Mourad Baïou ◽  
A. Ridha Mahjoub ◽  
Viet Hung Nguyen

Let G = (V, E) be an undirected graph where the edges in E have non-negative weights. A star in G is either a single node of G or a subgraph of G where all the edges share one common end-node. A star forest is a collection of vertex-disjoint stars in G. The weight of a star forest is the sum of the weights of its edges. This paper deals with the problem of finding a Maximum Weight Spanning Star Forest (MWSFP) in G. This problem is NP-hard but can be solved in polynomial time when G is a cactus [Nguyen, Discrete Math. Algorithms App. 7 (2015) 1550018]. In this paper, we present a polyhedral investigation of the MWSFP. More precisely, we study the facial structure of the star forest polytope, denoted by SFP(G), which is the convex hull of the incidence vectors of the star forests of G. First, we prove several basic properties of SFP(G) and propose an integer programming formulation for MWSFP. Then, we give a class of facet-defining inequalities, called M-tree inequalities, for SFP(G). We show that for the case when G is a tree, the M-tree and the nonnegativity inequalities give a complete characterization of SFP(G). Finally, based on the description of the dominating set polytope on cycles given by Bouchakour et al. [Eur. J. Combin. 29 (2008) 652–661], we give a complete linear description of SFP(G) when G is a cycle.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li-Qun Chen ◽  
Shweta Chhajed ◽  
Tong Zhang ◽  
Joseph M. Collins ◽  
Qiuying Pang ◽  
...  

AbstractDuring the past two decades, glucosinolate (GLS) metabolic pathways have been under extensive studies because of the importance of the specialized metabolites in plant defense against herbivores and pathogens. The studies have led to a nearly complete characterization of biosynthetic genes in the reference plant Arabidopsis thaliana. Before methionine incorporation into the core structure of aliphatic GLS, it undergoes chain-elongation through an iterative three-step process recruited from leucine biosynthesis. Although enzymes catalyzing each step of the reaction have been characterized, the regulatory mode is largely unknown. In this study, using three independent approaches, yeast two-hybrid (Y2H), coimmunoprecipitation (Co-IP) and bimolecular fluorescence complementation (BiFC), we uncovered the presence of protein complexes consisting of isopropylmalate isomerase (IPMI) and isopropylmalate dehydrogenase (IPMDH). In addition, simultaneous decreases in both IPMI and IPMDH activities in a leuc:ipmdh1 double mutants resulted in aggregated changes of GLS profiles compared to either leuc or ipmdh1 single mutants. Although the biological importance of the formation of IPMI and IPMDH protein complexes has not been documented in any organisms, these complexes may represent a new regulatory mechanism of substrate channeling in GLS and/or leucine biosynthesis. Since genes encoding the two enzymes are widely distributed in eukaryotic and prokaryotic genomes, such complexes may have universal significance in the regulation of leucine biosynthesis.


Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 146
Author(s):  
Catarina Xavier ◽  
Mayra Eduardoff ◽  
Barbara Bertoglio ◽  
Christina Amory ◽  
Cordula Berger ◽  
...  

The efficient extraction of DNA from challenging samples, such as bones, is critical for the success of downstream genotyping analysis in molecular genetic disciplines. Even though the ancient DNA community has developed several protocols targeting small DNA fragments that are typically present in decomposed or old specimens, only recently forensic geneticists have started to adopt those protocols. Here, we compare an ancient DNA extraction protocol (Dabney) with a bone extraction method (Loreille) typically used in forensics. Real-time quantitative PCR and forensically representative typing methods including fragment size analysis and sequencing were used to assess protocol performance. We used four bone samples of different age in replicates to study the effects of both extraction methods. Our results confirm Loreille’s overall increased gain of DNA when enough tissue is available and Dabney’s improved efficiency for retrieving shorter DNA fragments that is beneficial when highly degraded DNA is present. The results suggest that the choice of extraction method needs to be based on available sample, degradation state, and targeted genotyping method. We modified the Dabney protocol by pooling parallel lysates prior to purification to study gain and performance in single tube typing assays and found that up to six parallel lysates lead to an almost linear gain of extracted DNA. These data are promising for further forensic investigations as the adapted Dabney protocol combines increased sensitivity for degraded DNA with necessary total DNA amount for forensic applications.


Author(s):  
Vladimir Shikhman

AbstractWe study mathematical programs with switching constraints (for short, MPSC) from the topological perspective. Two basic theorems from Morse theory are proved. Outside the W-stationary point set, continuous deformation of lower level sets can be performed. However, when passing a W-stationary level, the topology of the lower level set changes via the attachment of a w-dimensional cell. The dimension w equals the W-index of the nondegenerate W-stationary point. The W-index depends on both the number of negative eigenvalues of the restricted Lagrangian’s Hessian and the number of bi-active switching constraints. As a consequence, we show the mountain pass theorem for MPSC. Additionally, we address the question if the assumption on the nondegeneracy of W-stationary points is too restrictive in the context of MPSC. It turns out that all W-stationary points are generically nondegenerate. Besides, we examine the gap between nondegeneracy and strong stability of W-stationary points. A complete characterization of strong stability for W-stationary points by means of first and second order information of the MPSC defining functions under linear independence constraint qualification is provided. In particular, no bi-active Lagrange multipliers of a strongly stable W-stationary point can vanish.


2011 ◽  
Author(s):  
Laszlo Veisz ◽  
Alexander Buck ◽  
Maria Nicolai ◽  
Karl Schmid ◽  
Chris M. S. Sears ◽  
...  

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