Pan Proteome of Xanthomonas campestris pv. campestris Isolates Contrasting in Virulence.

Fully sequenced genomes of Xanthomonas campestris pv. campestris (Xcc) strains are reported. However, intra-pathovar differences are still intriguing and far from clear. In this work, the contrasting virulence between two isolates of Xcc - Xcc51 (more virulent) and XccY21 (less virulent) is evaluated by determining their pan proteome profiles. The bacteria are grown in NYG and XVM1 (optimal for induction of hrp regulon) broths and collected at the max-exponential growth phase. Shotgun proteomics reveals a total of 329 proteins when Xcc isolates are grown in XVM1. A comparison of both profiles reveals 47 proteins with significant abundance fluctuations, out of which, 39 show an increased abundance in Xcc51 and are mainly involved in virulence/adaptation mechanisms, genetic information processing, and membrane receptor/iron transport systems, such as BfeA, BtuB, Cap, Clp, Dcp, FyuA, GroEs, HpaG, Tig, and OmpP6. Several differential proteins are further analyzed by qRT-PCR, which reveals a similar expression pattern to the protein abundance. The data shed light on the complex Xcc pathogenicity mechanisms and point out a set of proteins related to the higher virulence of Xcc51. This information is essential for the development of more efficient strategies aiming at the control of black rot disease.

Differential accumulation of Xanthomonas campestris pv. campestris proteins during the interaction with the host plant: Contributions of an in vivo system.

Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot, a highly destructive disease that affects all brassicas. This work aimed to study the interaction Xcc-Brassica oleracea using an in vivo system in an attempt to identify proteins involved in pathogenicity. We used label-free shotgun 2D-nanoUPLC/MSE to analyze Xcc proteins in three conditions: in the interaction with susceptible (REK) and resistant (REU) plants and in culture medium (control condition). A model of Xcc-susceptible host interaction is proposed and shows that Xcc increases the abundance of several crucial proteins for infection and cell protection. In this study, we also confirmed the differential expression by qPCR analysis of selected genes. This is the first report showing a large-scale identification of proteins in an in vivo host plant condition. Considering that most studies involving phytopathogens are in vitro (growth in culture medium or in plant extract), this work contributes with relevant information related to the plant-pathogen interaction in planta.

Nanofibers as drug-delivery systems for infection control in dentistry.

INTRODUCTION: Due to the complexity of different oral infections, new anti-infective nanotechnological approaches have been emerging for dentistry in recent years. These strategies may contribute to antimicrobial molecules delivery, tissue regeneration, and oral health maintenance by acting in a more specific site and not being cytotoxic. In this context, nanofibers appear as versatile structures and might act both in the release of antimicrobial molecules and as a scaffold for new tissue formation. AREAS COVERED: This review addresses the application of different nanofibers as new strategies for the delivery of antimicrobial molecules for dentistry. Here, we present the main polymers used to construct nanofibers, methods of production and mainly their antimicrobial activity against microorganisms commonly responsible for the usual dental infections. These biomaterials may be associated to restorative materials, prostheses, and mucoadhesive structures. Besides, nanofibers can be used for endodontic or periodontal therapy, or even on implant surfaces. EXPERT OPINION: A wide variety of studies report the potential application of anti-infective nanofibers in the oral cavity. Although there are still several barriers between in vitro and in vivo studies, these new formulations appear as promising new therapies for dentistry.

In silico characterization of class II plant defensins from Arabidopsis thaliana.

Defensins comprise a polyphyletic group of multifunctional defense peptides. Cis-defensins, also known as cysteine stabilized αß (CSαß) defensins, are one of the most ancient defense peptide families. In plants, these peptides have been divided into two classes, according to their precursor organization. Class I defensins are composed of the signal peptide and the mature sequence, while class II defensins have an additional C-terminal prodomain, which is proteolytically cleaved. Class II defensins have been described in Solanaceae and Poaceae species, indicating this class could be spread among all flowering plants. Here, a search by regular expression (RegEx) was applied to the Arabidopsis thaliana proteome, a model plant with more than 300 predicted defensin genes. Two sequences were identified, A7REG2 and A7REG4, which have a typical plant defensin structure and an additional C-terminal prodomain. TraVA database indicated they are expressed in flower, ovules and seeds, and being duplicated genes, this indicates they could be a result of a subfunctionalization process. The presence of class II defensin sequences in Brassicaceae and Solanaceae and evolutionary distance between them suggest class II defensins may be present in other eudicots. Discovery of class II defensins in other plants could shed some light on flower, ovules and seed physiology, as this class is expressed in these locations.