Effect of BvAgNP on growth, development, and glyoxalase gene expression analysis in Mammillaria bombycina and Selenicereus undatus.

BACKGROUND: Silver nanoparticles (AgNPs) have been used in plant tissue culture as growth stimulants, promoting bud initiation, germination, and rooting. In prior studies, AgNPs were synthesized and characterized by green synthesis using extracts from Beta vulgaris var. cicla (BvAgNP), and their functionality as seed disinfectant and antimicrobial was verified. In this study, we evaluated the effect of BvAgNP on the growth and development of Mammillaria bombycina and Selenicereus undatus in vitro, as well as the expression of glyoxalase genes. METHODS: Explants from M. bombycina and S. undatus in vitro were treated with 25, 50, and 100 mg/L of BvAgNP. After 90 days, morphological characteristics were evaluated, and the expression of glyoxalase genes was analyzed by qPCR. RESULTS: All treatments inhibited rooting for M. bombycina and no bud initiation was observed. S. undatus, showed a maximum response in rooting and bud generation at 25 mg/L of BvAgNP. Scanning electron microscopy (SEM) results exhibited a higher number of vacuoles in stem cells treated with BvAgNP compared to the control for both species. Expression of glyoxalase genes in M. bombycina increased in all treatments, whereas it decreased for S. undatus, however, increasing in roots. CONCLUSIONS: This study presents the effects of BvAgNP on the growth and development of M. bombycina and S. undatus, with the aim of proposing treatments that promote in vitro rooting and bud initiation.

Antimicrobial activity of the Flo peptide produced in Scenedesmus acutus and Nannochloropsis oculata.

The continuous increase of bacterial pathogen resistance to conventional antibiotics has challenged the research community to develop new antimicrobial strategies. Antimicrobial peptides (AMP) are a promising alternative to combat multidrug-resistant strains compared to conventional antibiotics because of their biocompatibility. In the present study, the Flo peptide, an AMP from the Moringa oleifera tree, was expressed in the chloroplast of the microalgae Nannochloropsis oculata and Scenedesmus acutus. The transgene insertion was verified by PCR amplification, and the homoplasmy was corroborated in spectinomycin-resistant lines. The identification and quantification of the peptide were performed using ELISA. The antimicrobial activity was studied against the Gram-negative Escherichia coli (ATCC 25,922) and Klebsiella pneumoniae (ATCC 700,603). The inflammatory response of the total soluble proteins of transplastomic N. oculata was assessed by measuring secretion of the cytokines IL-6, IL-10, and alpha-tumor necrosis (TNF-α), and cytotoxicity was assessed. These results provide a potential strategy to produce the Flo peptide in microalgae with antibacterial activities.

Genetic structure, phylogeography, and migration routes of Bouteloua gracilis (Kunth) Lag. ex Griffiths (Poaceae:Chloridoideae).

Blue grama grass (Bouteloua gracilis) populations are found in widely variable environments, tolerating drought, alkaline soils and different levels of grazing. Many ploidy levels have been reported for this species that is also considered to be phenotypically plastic and morphologically variable. Recently a decline in its cover and frequency in the North American shortgrass steppe and central Mexico has been reported although much about the biology of the species is unknown, including genetic diversity throughout its distribution. Genetic and phylogeographic structure and phylogenetic relationships among B. gracilis were estimated employing next generation sequencing of a high number of SNPs and loci. Population genetics and Structure analyses were performed. We compared the marginal likelihoods of different migration models using MIGRATE and obtained the best population model of migration for our data. Demographic expansion of B. gracilis was observed graphically with a mismatch distribution obtained in DNAsp. Bayesian and Maximum Likelihood methods were used to resolve phylogenetic relationships among B. gracilis and its closely related species as well as within B. gracilis populations. B. gracilis is sister to the B. chasei and B. herrera arrietae clade. Among the populations of the species two highly supported clades were resolved, grouping samples from Mexico and USA respectively. Allele frequencies determined three population clusters: CUSA from the Great Plains, MEX from central and southern Mexico, and WUSA-NMEX from northern Mexico and the western mountainous region of USA, the latter of which contains an allele admixture of the other two clusters. The haplotype network revealed an ancestral haplotype originating in Mexico, from which the rest of the haplotypes diversified to the north. Both evidence of gene flow and isolation among populations was observed. Genetic clusters are not genetically structured and variation is higher among populations. The genetic and morphological data do not support recognition of ecotypes or infraespecific taxa. However, the Great Plains populations are least diverse, making them most vulnerable to environmental change.

Production and purification of recombinant hypocholesterolemic peptides.

Elevated concentrations of cholesterol in plasma are associated with increased risk for heart diseases in humans. Bioactive peptides can be considered as an option to prevent or treat this condition. Currently, there are wide sources of bioactive peptides with hypocholesterolemic activities; however, most researches are focused in bioactive peptides derived from soybean and milk protein. Although there are several preparation methods for these peptides, it is a novel process to prepare bioactive peptides by genetic engineering techniques. In this review, after a general introduction on approaches and advances in bioactive peptides, recombinant strategies to generate hypocholesterolemic peptides and their purification are discussed as well as their application in food and drug design.

Identification and Profiling Analysis of microRNAs in Guava Fruit (Psidium guajava L.) and Their Role during Ripening.

The guava (Psidium guajava L.) is a climacteric fruit with an accelerated post-harvest overripening. miRNAs are small RNA sequences that function as gene regulators in eukaryotes and are essential for their survival and development. In this study, miRNA libraries were constructed, sequenced and analyzed from the breaker and ripe stages of guava fruit cv. Siglo XXI. One hundred and seventy-four mature miRNA sequences from 28 miRNA families were identified. The taxonomic distribution of the guava miRNAs showed a high level of conservation among the dicotyledonous plants. Most of the predicted miRNA target genes were transcription factors and genes involved in the metabolism of phytohormones such as abscisic acid, auxins, and ethylene, as revealed through an ontology enrichment analysis. The miRNA families miR168, miR169, miR396, miR397, and miR482 were classified as being directly associated with maturation, whereas the miRNA families miR160, miR165, miR167, miR3930, miR395, miR398, and miR535 were classified as being indirectly associated. With this study, we intended to increase our knowledge and understanding of the regulatory process involved in the ripening process, thereby providing valuable information for future research on the ripening of guava fruit.

Identification in silico and expression analysis of a ß-1-4-endoglucanase and ß-galactosidase genes related to ripening in guava fruit.

BACKGROUND: Guava fruit softening is a crucial process during ripening and this process involves a number of enzymes that modifies the cell wall. Two of the enzymes that regulate this process are (a) the ß-1, 4-endoglucanase 17 (BEG) which hydrolyze ß-1, 4 bonds from cellulose and hemicellulose, and (b) ß-galactosidase (BGA) that hydrolyzes pectin chains. Bioinformatics and expression analysis information on these genes is limited in guava fruit. RESULTS: A fragment of a ß-1, 4-endoglucanase 17 (PgE17), and another of a ß-galactosidase (PgGa1) were identified. These sequences have a similarity of more than 85% with those reported in the NCBI database. In the guava genome, one homologous sequence was found for PgE17 in Chr 4 and two homologous to PgGa1: one in Chr 3 and the other one in Chr 6. Putative protein PgE17 contains part of the glyco_hydro_9 domain. Putative protein PgGa1 has a part of the glyco_hydro_35 domain. Phylogenetic analysis of PgE17 and PgGa1 revealed that both are highly conserved inside the Myrtaceae family. In silico expression analysis showed that both PgE17 and PgGa1 work in a coordinated way with other cell wall modifier enzymes. Expression of these genes was found in all the guava samples analyzed. However, the highest expression was found in the fruit in the breaking and ripe states. CONCLUSIONS: A ß-1, 4-endoglucanase 17, and ß-galactosidase 1 sequences were identified. PgE17 and PgGa1 are expressed in all the plant tissues, and fruit ripening states. Although, the highest expression was on breaker and ripe states.

De Novo Transcriptome of Mammillaria bombycina (Cactaceae) under In Vitro Conditions and Identification of Glyoxalase Genes.

Mammillaria bombycina is a cactus distributed in the central region of Mexico. Cactaceae have the particularity of surviving drought and high temperatures, which is why in vitro propagation studies have been carried out successfully to preserve this species and use it as a study model in cacti. In this contribution, a de novo transcriptome of M. bombycina was produced under in vitro conditions for the identification and expression of genes related to abiotic stress. Samples were sequenced using an Illumina platform, averaging 24 million clean readings. From assembly and annotation, 84,975 transcripts were generated, 55% of which were unigenes. Among these, the presence of 13 isoforms of genes belonging to glyoxalase I, II and III were identified. An analysis of the qRT-PCR expression of these genes was performed under in vitro and ex vitro conditions and dehydration at 6 and 24 h. The highest expression was observed under greenhouse conditions and dehydration at 24 h, according to the control. The de novo assembly of the M. bombycina transcriptome remains a study model for future work in cacti.

[Mobbing: its relationships with organizational culture and personal outcomes]. / Acoso laboral: relaciones con la cultura organizacional y los resultados personales.

A study dealing with the effects of both organizational culture and mobbing on personal and organizational outcomes of a sample of Spanish emergency workers, is reported here. It was found that there is a strong impact of organizational culture dimensions on mobbing, and that mobbing affects job satisfaction, organizational commitment and organizational citizenship behaviour. Results concerning organizational commitment show that this variable is not a mere effect of mobbing in general, but rather that it is also a direct impact of culture on this outcome.

Identificaciones múltiples y ciudadanía en el trabajo: mediación de las fuentes de apoyo social / Multiple identifications and citizenship at work: mediation of social support

Este estudio examina las relaciones entre la identificación con la organización, el grupo y la carrera con las conductas de ciudadanía orientadas a la organización, al grupo y a la profesión. Además, este trabajo analiza el papel mediador del apoyo social percibido desde diferentes fuentes -organizacional y grupal- en las relaciones entre la identificación y las conductas de ciudadanía. Los modelos de ecuaciones estructurales, realizados sobre una muestra de 435 trabajadores españoles que pertenecían a 87 grupos de trabajo, muestran que la identificación con la organización, con el grupo y con la carrera son dimensiones diferentes, aunque positivamente relacionadas, y que predicen las conductas de ciudadanía orientadas a los tres focos. Asimismo, los resultados indican que el apoyo organizacional percibido media parcialmente las relaciones entre la identificación organizacional y las conductas de ciudadanía orientadas a la organización, mientras que el apoyo grupal percibido media parcialmente las relaciones entre la identificación grupal y las conductas de ciudadanía orientadas al grupo. Estos resultados confirman y expanden los hallazgos previos sobre identificación y conductas de ciudadanía.

This paper examines the relationships between organizational, group, and career identification with organizational, group, and career citizenship behavior. In addition, this study analyzes the mediator role of perceived social support from different sources -organizational and group- on identification and citizenship behavior. Using a sample of 435 Spanish workers, nested into 87 work groups, we found full support for our hypotheses. Structural Equation Modeling (SEM) showed that organizational, group, and career identification are different but related dimensions, and predictors of the three citizenship behavior foci. Results also showed that the effect of organizational identification on organizational citizenship behavior is partially mediated by perceived organizational support partially, while perceived group support partially mediates the relationship between group identification and group citizenship behavior. These results confirm and extend previous research on identification and citizenship behavior.