RESUMEN

De novo root regeneration (DNRR) is a developmental process that regenerates adventitious roots from wounded tissues. Phytohormone signaling pathways involved in microbial resistance are mobilized after cutting and influence de novo root regeneration. Microbes may positively or negatively influence the development and stress responses of a plant. However, most studies on the molecular mechanisms of de novo organogenesis are performed in aseptic conditions. Thus, the potential crosstalk between organ regeneration and biotic stresses is underexplored. Here, we report the development of a versatile experimental system to study the impact of microbes on DNRR. Using this system, we found that bacteria inhibited root regeneration by activation of, but not limited to, pathogen-associated molecular pattern (PAMP)-triggered immunity. Sensing bacteria-derived flagellin 22 peptide (flg22) inhibited root regeneration by interfering with the formation of an auxin maximum at the wound site. This inhibition relies on the receptor complex that recognizes microbial patterns but may bypass the requirement of salicylic acid signaling.

Asunto(s)

Proteínas de Arabidopsis , Arabidopsis , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Ácidos Indolacéticos/metabolismo , Raíces de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas

RESUMEN

Galectins belong to the family of carbohydrate-binding proteins and play major roles in the immune and inflammatory responses of both vertebrates and invertebrates. In the present study, one novel galectin-1 protein named AjGal-1 was identified from Apostichopus japonicas with an open reading frame of 1179 bp encoding a polypeptide of 392 amino acids. The deduced amino acids sequence of AjGal-1 contained three carbohydrate recognition domains (CRDs) which shared 34-37% identity with that of other galectin proteins from echinodermata, fishes, and birds. In the phylogenetic tree, AjGal-1 was closely clustered with galectins from Mesocentrotus nudus and Paracentrotus lividus. The mRNA transcripts of AjGal-1 were ubiquitously expressed in all the detected tissues, including gut, longitudinal muscle, gonad, coelomocytes, respiratory tree, tentacle and body wall, with the highest expression level in coelomocytes. After Vibrio splendidus stimulation, the mRNA expression levels of AjGal-1 in coelomocytes were significantly increased at 6 and 12 h (P < 0.01) compared with that in control group, and went back to normal level at 72 h. The recombinant protein of AjGal-1 (rAjGal-1) could bind various PAMPs including d-galactose, lipopolysaccharide (LPS), peptidoglycan (PGN) and mannose (Man), and exhibited the highest affinity to d-galactose. Meanwhile, rAjGal-1 could also bind and agglutinate different kinds of microorganisms, including gram-negative bacteria (V. splendidus and Escherichia coli), gram-positive bacteria (Micrococus leteus), and fungi (Pichia pastoris). rAjGal-1 also exhibited anti-microbial activity against V. splendidus and E. coli. All these results suggested that AjGal-1 could function as an important PRR with broad spectrum of microbial recognition and anti-microbial activity against the invading pathogen in A. japonicas.

Asunto(s)

Galectina 1/genética , Galectina 1/inmunología , Inmunidad Innata , Moléculas de Patrón Molecular Asociado a Patógenos , Stichopus/genética , Vibriosis/veterinaria , Aglutinación , Animales , Galectina 1/aislamiento & purificación , Regulación de la Expresión Génica , Bacterias Gramnegativas , Bacterias Grampositivas , Filogenia , Stichopus/inmunología , Vibrio , Vibriosis/inmunología

RESUMEN

Rimicaris exoculata (Decapoda: Bresiliidae) is one of the dominant species of hydrothermal vent communities, which inside its gill chamber harbors ectosymbioses with taxonomic invariability while compositional flexibility. Several studies have revealed that the establishment of symbiosis can be initiated and selected by innate immunity-related pattern recognition receptors (PRRs), such as C-type lectins (CTLs). In this research, a CTL was identified in R. exoculata (termed RCTL), which showed high expression at both mRNA and protein levels in the scaphognathite, an organ where the ectosymbionts are attached outside its setae. Linear correlationships were observed between the relative quantities of two major symbionts and the expression of RCTL based on analyzing different shrimp individuals. The recombinant protein of RCTL could recognize and agglutinate the cultivable γ-proteobacterium of Escherichia coli in a Ca2+-dependent manner, obeying a dose-dependent and time-cumulative pattern. Unlike conventional crustacean CTLs, the involvement of RCTL could not affect the bacterial growth, which is a key issue for the successful establishment of symbiosis. These results implied that RCTL might play a critical role in symbiotic recognition and attachment to R. exoculata. It also provides insights to understand how R. exoculata adapted to such a chemosynthesis-based environment.

Asunto(s)

Decápodos/genética , Decápodos/inmunología , Inmunidad Innata/genética , Lectinas Tipo C/genética , Lectinas Tipo C/inmunología , Secuencia de Aminoácidos , Animales , Proteínas de Artrópodos/química , Proteínas de Artrópodos/genética , Proteínas de Artrópodos/inmunología , Secuencia de Bases , Escherichia coli/fisiología , Perfilación de la Expresión Génica , Lectinas Tipo C/química , Filogenia , Alineación de Secuencia , Simbiosis

RESUMEN

Although Ixodes scapularis and other related tick species are considered prolific vectors for a number of important human diseases, many aspects of their biology, microbial interactions, and immunity are largely unknown; in particular, how these ancient vectors recognize invading pathogens like Borrelia burgdorferi and influence their persistence. The analysis of the Ixodes genome and a limited set of transcriptomic data have established that ticks encode many components of classical immune pathways; yet at the same time, they lack many key orthologs of these recognition networks. Therefore, whether a given immune pathway is active in Ixodes ticks and how precisely they exert its microbicidal functions are only incompletely delineated. A few recent studies have suggested that classical pathways like the Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) as well as immunodeficiency (IMD) pathways are fully functional in I. scapularis, and upon challenge with microbes, generate potent microbicidal responses against diverse tick-borne pathogens including B. burgdorferi. These studies also highlight novel concepts of vector immunity that include both a direct and an indirect mode of recognition of pathogens, as well as the influence of the gut microbiome, which ultimately dictates the outcome of a robust microbicidal response. Further understanding of how Ixodes ticks recognize and suppress invading microbes like B. burgdorferi will enrich our fundamental knowledge of vector immunobiology, thereby contributing to the development of future interventions to better control the tick-borne pathogen.

Asunto(s)

Borrelia burgdorferi/inmunología , Inmunidad , Ixodes/inmunología , Enfermedad de Lyme/inmunología , Animales , Antiinfecciosos , Vectores Arácnidos/genética , Vectores Arácnidos/inmunología , Vectores Arácnidos/microbiología , Borrelia burgdorferi/patogenicidad , Microbioma Gastrointestinal/inmunología , Genoma de los Insectos , Interacciones Huésped-Patógeno/inmunología , Ixodes/genética , Ixodes/microbiología , Enfermedad de Lyme/microbiología , Transducción de Señal , Transcriptoma , Tirosina/análogos & derivados , Tirosina/genética , Tirosina/inmunología , Tirosina/metabolismo

RESUMEN

BACKGROUND: Tremendous efforts through dedicated research have been made for the development of robust, point of care, portable, cost effective, sensitive and specific assays of microbial detection. Biosensing and nanotechnology offer novel strategies of designing state of the art devices and assay formats with enhanced sensitivity and all other desired features. Monoclonal antibodies have been in use as biorecognition elements for decades. However, recent studies have demonstrated superiority of aptamers to monoclonal antibodies in a number of applications. Many of the research groups have successfully utilized aptamers as capture probes in developing biosensors for microbial detection. OBJECTIVES: The main objective of this review article is to present the reader with an overview of the recent advances made in the field of aptamers and aptasensors for the detection and identification of microbial agents. RESULTS: Our search for relevant information on current advances on aptamers and aptasensors has revealed that a number of successful attempts have been made in the last two decades for the selection of aptamers as well as their applications in aptasensors for microbial detection. CONCLUSION: Aptamers and aptasensors, although in their infancy, may find promising application in rapid, sensitive, point of care and cost effective microbial detection.

Asunto(s)

Aptámeros de Nucleótidos/farmacología , Técnicas Microbiológicas/métodos , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Técnicas Biosensibles , Hongos/aislamiento & purificación , Hongos/metabolismo , Humanos , Nanoestructuras , Toxinas Biológicas/metabolismo , Virus/aislamiento & purificación , Virus/metabolismo

RESUMEN

Nosema ceranae causes widespread infection in adult workers of European honey bees, Apis mellifera, and has often been linked to honey bee colony losses worldwide. Previous investigations of honey bee immune response to N. ceranae infection were largely based on laboratory experiment, however, little is known about the immune response of honey bees that are naturally infected by N. ceranae. Here, we compared the infection levels of N. ceranae in three different categories of adult bees (emergent bees, nurses, and foragers) and detected the host immune response to the N. ceranae infection under natural conditions. Our studies showed that the Nosema spore load and infection prevalence varied among the different types of adult workers, and both of them increased as honey bees aged: No infection was detected in emergent bees, nurses had a medium spore load and prevalence, while foragers were with the highest Nosema infection level and prevalence. Quantification of the mRNA levels of antimicrobial peptides (abaecin, apidaecin, defensin-1, defensin-2, and hymenoptaecin) and microbial recognition proteins (PGRP-S1, PGRP-S2, PGRP-S3, PGRP-LC, GNBP1-1, and GNBP1-2) confirmed the involvement of the Toll and/or Imd immune pathways in the host response to N. ceranae infection, and revealed an activation of host immune response by N. ceranae infection under natural conditions. Additionally, the levels of immune response were positively correlated with the Nosema spore loads in the infected bees. The information gained from this study will be relevant to the predictive modeling of honey bee disease dynamics for Nosema disease prevention and management.

Asunto(s)

Abejas/microbiología , Nosema/inmunología , Animales , Péptidos Catiónicos Antimicrobianos/genética , Abejas/genética , Abejas/inmunología , Defensinas/genética , Femenino , Proteínas de Insectos/genética , Nosema/genética , Esporas Fúngicas

RESUMEN

CD209 is an immune receptor that plays an important role in the initiation of innate immunity and activation of adaptive immunity in mammals. However, much less is known about the immunological function of CD209 in lower vertebrates. In the present study, we examined the immune effect of a CD209 homologue (CsCD209) from the teleost fish tongue sole Cynoglossus semilaevis. CsCD209 possesses a lectin domain that shares high levels of similarity with the lectin domains of human and mouse CD209. CsCD209 expression was most abundant in kidney and blood and was significantly upregulated during bacterial infection. CsCD209 exhibited a subcellular localization mainly on the cell surface of myelomonocytes. Recombinant CsCD209 displayed apparent binding capacities to a broad range of bacteria and fungi, and significantly promoted the phagocytosis of the bound bacteria by C. semilaevis leukocytes. Collectively, the results indicate that teleost CD209 serves as a pattern recognition receptor that exerts an influence on the phagocytosis process during pathogen infections.

Asunto(s)

Moléculas de Adhesión Celular/metabolismo , Interacciones Huésped-Patógeno , Lectinas Tipo C/metabolismo , Fagocitosis , Receptores de Superficie Celular/metabolismo , Receptores de Reconocimiento de Patrones/metabolismo , Secuencia de Aminoácidos , Animales , Bacterias/inmunología , Bacterias/metabolismo , Secuencia de Bases , Moléculas de Adhesión Celular/química , Moléculas de Adhesión Celular/genética , Proteínas de Peces/química , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Expresión Génica , Humanos , Lectinas Tipo C/química , Lectinas Tipo C/genética , Modelos Moleculares , Especificidad de Órganos/genética , Filogenia , Unión Proteica , Conformación Proteica , Receptores de Superficie Celular/química , Receptores de Superficie Celular/genética , Receptores de Reconocimiento de Patrones/química , Receptores de Reconocimiento de Patrones/genética , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Levaduras/inmunología , Levaduras/metabolismo

Asunto(s)

Biología Celular , Plantas/microbiología , Transporte Biológico , Señalización del Calcio , Membrana Celular/metabolismo , Citoesqueleto/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteolisis

RESUMEN

Galectins constitute a conserved and widely distributed lectin family characterized by their binding affinity for ß-galactosides and a unique binding site sequence motif in the carbohydrate recognition domain (CRD). In spite of their structural conservation, galectins display a remarkable functional diversity, by participating in developmental processes, cell adhesion and motility, regulation of immune homeostasis, and recognition of glycans on the surface of viruses, bacteria and protozoan parasites. In contrast with mammals, and other vertebrate and invertebrate taxa, the identification and characterization of bona fide galectins in aquatic mollusks has been relatively recent. Most of the studies have focused on the identification and domain organization of galectin-like transcripts or proteins in diverse tissues and cell types, including hemocytes, and their expression upon environmental or infectious challenge. Lectins from the eastern oyster Crassostrea virginica, however, have been characterized in their molecular, structural and functional aspects and some notable features have become apparent in the galectin repertoire of aquatic mollusks. These including less diversified galectin repertoires and different domain organizations relative to those observed in vertebrates, carbohydrate specificity for blood group oligosaccharides, and up regulation of galectin expression by infectious challenge, a feature that supports their proposed role(s) in innate immune responses. Although galectins from some aquatic mollusks have been shown to recognize microbial pathogens and parasites and promote their phagocytosis, they can also selectively bind to phytoplankton components, suggesting that they also participate in uptake and intracellular digestion of microalgae. In addition, the experimental evidence suggests that the protozoan parasite Perkinsus marinus has co-evolved with the oyster host to be selectively recognized by the oyster hemocyte galectins over algal food or bacterial pathogens, thereby subverting the oyster's innate immune/feeding recognition mechanisms to gain entry into the host cells.

Asunto(s)

Evolución Molecular , Galectinas/genética , Moluscos/genética , Moluscos/inmunología , Animales , Galectinas/metabolismo , Moluscos/metabolismo

RESUMEN

Haemocyanin is an important non-specific immune protein present in the hemolymph of invertebrates, which have the ability to recognize the microbial pathogens and trigger the innate immune system. In this study, we isolated and purified the haemocyanin using gel filtration chromatography and investigated its microbial recognition mechanism against the invading pathogens. Kuruma shrimp Marsupenaeus japonicus haemocyanin showed the single band with a molecular weight of 76 kDa on SDS-PAGE and its molecular mass was analysed through the MALDI. Pathogen recognition mechanism of M. japonicus haemocyanin was detected through bacterial agglutination, agglutination inhibition and prophenoloxidase activity. M. japonicus haemocyanin agglutinate all human blood RBC types and showed the bacterial agglutination against all tested Gram positive Staphylococcus aureus, Enterococcus faecalis and Bacillus subtilis and Gram negative Pseudomonas aeruginosa, Proteus vulgaris and Vibrio parahaemolyticus at the concentrations ranging from 30 to 50 µg/ml. Agglutination was inhibited by 50-200 mM of N-acetylneuraminic acid, a-D-glucose, D-galactose and D-xylose. Our results suggest that, 76 kDa subunit of M. japonicus haemocyanin recognize the pathogenic surface proteins which are present on the outer membrane of the bacteria and mediates the bacterial agglutination through haemocytes. This bacterial agglutination was visualized through Confocal Laser Scanning Microscopy (CLSM). This present study would be helpful to explore the importance of haemocyanin in innate immune response of M. japonicus and its eliciting pathogen recognition mechanism leads to the development of innate immunity in crustaceans.

Asunto(s)

Hemocianinas/química , Hemocianinas/metabolismo , Penaeidae/enzimología , Aglutinación/inmunología , Pruebas de Aglutinación , Secuencia de Aminoácidos , Animales , Bacterias/inmunología , Pruebas de Inhibición de Hemaglutinación , Hemocianinas/aislamiento & purificación , Interacciones Huésped-Patógeno/inmunología , Humanos , Inmunidad Innata , Metales/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Peso Molecular , Monofenol Monooxigenasa/metabolismo , Penaeidae/inmunología , Unión Proteica , Subunidades de Proteína , Alineación de Secuencia , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción

RESUMEN

Galectins are characterized by their binding affinity for ß-galactosides, a unique binding site sequence motif, and wide taxonomic distribution and structural conservation in vertebrates, invertebrates, protista, and fungi. Since their initial description, galectins were considered to bind endogenous ("self") glycans and mediate developmental processes and cancer. In the past few years, however, numerous studies have described the diverse effects of galectins on cells involved in both innate and adaptive immune responses, and the mechanistic aspects of their regulatory roles in immune homeostasis. More recently, however, evidence has accumulated to suggest that galectins also bind exogenous ("non-self") glycans on the surface of potentially pathogenic microbes, parasites, and fungi, suggesting that galectins can function as pattern recognition receptors (PRRs) in innate immunity. Thus, a perplexing paradox arises by the fact that galectins also recognize lactosamine-containing glycans on the host cell surface during developmental processes and regulation of immune responses. According to the currently accepted model for non-self recognition, PRRs recognize pathogens via highly conserved microbial surface molecules of wide distribution such as LPS or peptidoglycan (pathogen-associated molecular patterns; PAMPs), which are absent in the host. Hence, this would not apply to galectins, which apparently bind similar self/non-self molecular patterns on host and microbial cells. This paradox underscores first, an oversimplification in the use of the PRR/PAMP terminology. Second, and most importantly, it reveals significant gaps in our knowledge about the diversity of the host galectin repertoire, and the subcellular targeting, localization, and secretion. Furthermore, our knowledge about the structural and biophysical aspects of their interactions with the host and microbial carbohydrate moieties is fragmentary, and warrants further investigation.