Scale-up of Aflatoxin Purification by Centrifugal Partition Chromatography.

Aflatoxins (AFs) are a group of secondary metabolites that cause several diseases in both animals and humans. Since the discovery of this group of toxins, several effects were revealed, such as hepatic changes, carcinoma, failure, and cancer of the liver. In the European Union, there are concentration limits for this group of mycotoxins in food and feed products; thus, these substances are required in their pure forms to prepare reference standards or certified reference materials.

Enhanced Antibacterial Activity of Substituted Derivatives of NCR169C Peptide.

in symbiosis with its rhizobial bacterium partner produces more than 700 nodule-specific cysteine-rich (NCR) peptides with diverse physicochemical properties. Most of the cationic NCR peptides have antimicrobial activity and the potential to tackle antimicrobial resistance with their novel modes of action. This work focuses on the antibacterial activity of the NCR169 peptide derivatives as we previously demonstrated that the C-terminal sequence of NCR169 (NCR169C) has antifungal activity, affecting the viability, morphology, and biofilm formation of various species.

Legume Plant Peptides as Sources of Novel Antimicrobial Molecules Against Human Pathogens.

Antimicrobial peptides are prominent components of the plant immune system acting against a wide variety of pathogens. Legume plants from the inverted repeat lacking clade (IRLC) have evolved a unique gene family encoding nodule-specific cysteine-rich NCR peptides acting in the symbiotic cells of root nodules, where they convert their bacterial endosymbionts into non-cultivable, polyploid nitrogen-fixing cells. NCRs are usually 30-50 amino acids long peptides having a characteristic pattern of 4 or 6 cysteines and highly divergent amino acid composition.

The Gene Is Crucial for the Progression of Bacterial Infection During Symbiosis.

Legumes are able to meet their nitrogen need by establishing nitrogen-fixing symbiosis with rhizobia. Nitrogen fixation is performed by rhizobia, which has been converted to bacteroids, in newly formed organs, the root nodules. In the model legume , nodule cells are invaded by rhizobia through transcellular tubular structures called infection threads (ITs) that are initiated at the root hairs.

Symbiotic NCR Peptide Fragments Affect the Viability, Morphology and Biofilm Formation of Species.

The increasing rate of fungal infections causes global problems not only in human healthcare but agriculture as well. To combat fungal pathogens limited numbers of antifungal agents are available therefore alternative drugs are needed. Antimicrobial peptides are potent candidates because of their broad activity spectrum and their diverse mode of actions.

Corrigendum: Structural Diversity and Bioactivities of Peptaibol Compounds From the Longibrachiatum Clade of the Filamentous Fungal Genus .

[This corrects the article DOI: 10.3389/fmicb.2019.

Stereoselective synthesis and application of isopulegol-based bi- and trifunctional chiral compounds.

A new family of isopulegol-based bi- and trifunctional chiral ligands was developed from commercially available (-)-isopulegol. Nucleophilic addition of primary amines towards (+)-α-methylene-γ-butyrolactone was accomplished, followed by reduction of the obtained β-aminolactones to provide aminodiols in highly stereoselective reactions. Epoxidation of (-)-isopulegol and subsequent oxirane ring opening with primary amines resulted in -substituted aminodiols.

Potent Chimeric Antimicrobial Derivatives of the NCR247 Symbiotic Peptide.

In Rhizobium-legume symbiosis, the bacteria are converted into nitrogen-fixing bacteroids. In many legume species, differentiation of the endosymbiotic bacteria is irreversible, culminating in definitive loss of their cell division ability. This terminal differentiation is mediated by plant peptides produced in the symbiotic cells.

Structural Diversity and Bioactivities of Peptaibol Compounds From the Longibrachiatum Clade of the Filamentous Fungal Genus .

This study examined the structural diversity and bioactivity of peptaibol compounds produced by species from the phylogenetically separated Longibrachiatum Clade of the filamentous fungal genus , which contains several biotechnologically, agriculturally and clinically important species. HPLC-ESI-MS investigations of crude extracts from 17 species of the Longibrachiatum Clade (. , and ) revealed several new and recurrent 20-residue peptaibols related to trichobrachins, paracelsins, suzukacillins, saturnisporins, trichoaureocins, trichocellins, longibrachins, hyporientalins, trichokonins, trilongins, metanicins, trichosporins, gliodeliquescins, alamethicins and hypophellins, as well as eight 19-residue sequences from a new subfamily of peptaibols named brevicelsins.

A protein complex required for polar growth of rhizobial infection threads.

During root nodule symbiosis, intracellular accommodation of rhizobia by legumes is a prerequisite for nitrogen fixation. For many legumes, rhizobial colonization initiates in root hairs through transcellular infection threads. In Medicago truncatula, VAPYRIN (VPY) and a putative E3 ligase LUMPY INFECTIONS (LIN) are required for infection thread development but their cellular and molecular roles are obscure.

Separation and Purification of Aflatoxins by Centrifugal Partition Chromatography.

Aflatoxins are mycotoxins that are produced by several species of filamentous fungi. In the European Union, the concentration limits for this group of mycotoxins in food and feed products are very low (on the order of parts per billion). Thus, relatively high amounts of these substances in their pure forms are required as reference standards.

Independent Regulation of Symbiotic Nodulation by the SUNN Negative and CRA2 Positive Systemic Pathways.

Plant systemic signaling pathways allow the integration and coordination of shoot and root organ metabolism and development at the whole-plant level depending on nutrient availability. In legumes, two systemic pathways have been reported in the model to regulate root nitrogen-fixing symbiotic nodulation. Both pathways involve leucine-rich repeat receptor-like kinases acting in shoots and proposed to perceive signaling peptides produced in roots depending on soil nutrient availability.

Impact of Plant Peptides on Symbiotic Nodule Development and Functioning.

Ribosomally synthesized peptides have wide ranges of functions in plants being, for example, signal molecules, transporters, alkaloids, or antimicrobial agents. Legumes are an unprecedented rich source of peptides, which are used to control the symbiosis of these plants with the nitrogen-fixing bacteria. Here, we discuss the function and the evolution of these peptides playing an important role in the formation or functioning of the symbiotic organs, the root nodules.

NAD1 Controls Defense-Like Responses in Medicago truncatula Symbiotic Nitrogen Fixing Nodules Following Rhizobial Colonization in a BacA-Independent Manner.

Legumes form endosymbiotic interaction with host compatible rhizobia, resulting in the development of nitrogen-fixing root nodules. Within symbiotic nodules, rhizobia are intracellularly accommodated in plant-derived membrane compartments, termed symbiosomes. In mature nodule, the massively colonized cells tolerate the existence of rhizobia without manifestation of visible defense responses, indicating the suppression of plant immunity in the nodule in the favur of the symbiotic partner.

The evaluation of 5-amino- and 5-hydroxyuracil derivatives as potential quadruplex-forming agents.

5-Substituted uracils (NH or OH groups in position 5) have been examined theoretically and experimentally as potential building blocks in quadruplex structures. Our high level Density Functional Theory (DFT) calculations showed that the tetramer formation and stacking energies for 5-substituted uracils are similar to the energies of purine-based xanthine (X) or guanine (G) structures. As tetrads of 5-substituted uracils cover almost exactly the same area as purine tetrads, mixed tetrads or quadruplex structures based on X or G and 5-substituted uracil motifs are possible.

A vapBC-type toxin-antitoxin module of Sinorhizobium meliloti influences symbiotic efficiency and nodule senescence of Medicago sativa.

The symbiotic nitrogen-fixing soil bacterium Sinorhizobium meliloti carries a large number of toxin-antitoxin (TA) modules both on the chromosome and megaplasmids. One of them, the vapBC-5 module that belongs to the type II systems was characterized here. It encodes an active toxin vapC-5, and was shown to be controlled negatively by the complex of its own proteins.

LIN, a novel type of U-box/WD40 protein, controls early infection by rhizobia in legumes.

The formation of a nitrogen-fixing nodule requires the coordinated development of rhizobial colonization and nodule organogenesis. Based on its mutant phenotype, lumpy infections (lin), LIN functions at an early stage of the rhizobial symbiotic process, required for both infection thread growth in root hair cells and the further development of nodule primordia. We show that spontaneous nodulation activated by the calcium- and calmodulin-dependent protein kinase is independent of LIN; thus, LIN is not necessary for nodule organogenesis.

Large-scale insertional mutagenesis using the Tnt1 retrotransposon in the model legume Medicago truncatula.

Medicago truncatula is a fast-emerging model for the study of legume functional biology. We used the tobacco retrotransposon Tnt1 to tag the Medicago genome and generated over 7600 independent lines representing an estimated 190,000 insertion events. Tnt1 inserted on average at 25 different locations per genome during tissue culture, and insertions were stable during subsequent generations in soil.

Molecular and cytological responses of Medicago truncatula to Erysiphe pisi.

SUMMARY Powdery mildew is an economically important disease in a number of crop legumes; however, little is known about resistance to the disease in these species. To gain a better understanding of the genetics of resistance and plant responses to powdery mildew in legumes, we developed a pathosystem with Medicago truncatula and Erysiphe pisi. Screening accessions of M.

Strategies to obtain stable transgenic plants from non-embryogenic lines: complementation of the nn1 mutation of the NORK gene in Medicago sativa MN1008.

Strategies to introduce genes into non-embryogenic plants for complementation of a mutation are described and tested on tetraploid alfalfa (Medicago sativa). Genes conditioning embryogenic potential, a mutant phenotype, and a gene to complement the mutation can be combined using several different crossing and selection steps. In the successful strategy used here, the M.

Distribution of microsatellites in the genome of Medicago truncatula: a resource of genetic markers that integrate genetic and physical maps.

Microsatellites are tandemly repeated short DNA sequences that are favored as molecular-genetic markers due to their high polymorphism index. Plant genomes characterized to date exhibit taxon-specific differences in frequency, genomic location, and motif structure of microsatellites, indicating that extant microsatellites originated recently and turn over quickly. With the goal of using microsatellite markers to integrate the physical and genetic maps of Medicago truncatula, we surveyed the frequency and distribution of perfect microsatellites in 77 Mbp of gene-rich BAC sequences, 27 Mbp of nonredundant transcript sequences, 20 Mbp of random whole genome shotgun sequences, and 49 Mbp of BAC-end sequences.

Transcript analysis of early nodulation events in Medicago truncatula.

Within the first 72 h of the interaction between rhizobia and their host plants, nodule primordium induction and infection occur. We predicted that transcription profiling of early stages of the symbiosis between Medicago truncatula roots and Sinorhizobium meliloti would identify regulated plant genes that likely condition key events in nodule initiation. Therefore, using a microarray with about 6,000 cDNAs, we compared transcripts from inoculated and uninoculated roots corresponding to defined stages between 1 and 72 h post inoculation (hpi).

Significant microsynteny with new evolutionary highlights is detected between Arabidopsis and legume model plants despite the lack of macrosynteny.

The increased amount of data produced by large genome sequencing projects allows scientists to carry out important syntenic studies to a great extent. Detailed genetic maps and entirely or partially sequenced genomes are compared, and macro- and microsyntenic relations can be determined for different species. In our study, the syntenic relationships between key legume plants and two model plants, Arabidopsis thaliana and Populus trichocarpa were investigated.

LIN, a Medicago truncatula gene required for nodule differentiation and persistence of rhizobial infections.

Ethyl methanesulfonate mutagenesis of the model legume Medicago truncatula has previously identified several genes required for early steps in nodulation. Here, we describe a new mutant that is defective in intermediate steps of nodule differentiation. The lin (lumpy infections) mutant is characterized by a 4-fold reduction in the number of infections, all of which arrest in the root epidermis, and by nodule primordia that initiate normally but fail to mature.