The Bashan Institute of Science

Auburn, AL, United States

The Bashan Institute of Science

Auburn, AL, United States
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Lopez B.R.,Environmental Microbiology Group | Lopez B.R.,The Bashan Institute of Science | Hernandez J.-P.,The Bashan Institute of Science | Hernandez J.-P.,El Bosque University | And 6 more authors.
Journal of Microbiological Methods | Year: 2017

Isolation of nucleic acids from Chlorella is difficult, given the chemically complex nature of their cell walls and variable production of metabolites. Immobilization of microalgae in polymers adds additional difficulty. Here, we modified, amended, and standardized methods for isolation of nucleic acids and compared the yield of DNA and RNA from free-living and encapsulated microalgae C. sorokiniana. Isolation of nucleic acids from immobilized cells required two steps in dissolving the alginate matrix, releasing the cells, and mechanical disruption with glass beads. For DNA extraction, we used modified versions of a commercial kit along with the hexadecyltrimethylammonium bromide (CTAB) method. For RNA extraction, we used the commercial TRI reagent procedure and the CTAB-dithiotreitol method. Quantity and quality of nucleic acids in extracts varied with growth conditions, isolation procedures, and time of incubation of the original culture. There were consistently higher amounts of DNA and RNA in extracts from immobilized cells. Quantitatively, the modified procedure with the commercial Promega kit was the most reliable procedure for isolating DNA and a modified commercial TRI reagent procedure was the choice for isolating RNA. All four procedures eliminated proteins efficiently and had low levels of contamination from residual polysaccharides from the matrices and/or metabolites naturally produced by the microalgae. All DNA extracts under both growth conditions, time of incubation, and two isolation methods successfully amplified the 18S ribosomal RNA by PCR and quantitative reverse transcription (RT-qPCR). © 2017 Elsevier B.V.


Pereg L.,University of New England of Australia | de-Bashan L.E.,Environmental Microbiology Group | de-Bashan L.E.,The Bashan Institute of Science | de-Bashan L.E.,Auburn University | And 3 more authors.
Plant and Soil | Year: 2016

Background: Azospirillum spp. are the most studied plant growth-promoting bacteria (PGPB). The genus represents a common model for plant-bacteria interactions. This genus was initially isolated and tested on cereals and was subsequently commercialized. Aims: Despite claims of plant specificity, particularly towards cereals, data over the past 40 years does not appear to substantiate claims of such specificity/affinity of Azospirillum species. Consequently an evaluation of the specificity/affinity of the genus Azospirillum across all plants, in general, and cereals, in particular, was undertaken. Results: Although the majority of studies focused on cereals, Azospirillum spp. increase growth of 113 plant species across 35 botanical families, including 14 species of cereals. Amongst Azospirillum spp. several well studied strains have been effective in several plant species, making these organisms potentially valuable for further study. Conclusions: This review demonstrates that azospirilla are not cereal-specific at the genus and species levels. Azospirillum serves as a general PGPB to every plant species tested so far. Given the paucity of widespread screening, affinity of strains to a plant genotype, cultivar, or plant species cannot be overruled. Definitive conclusions concerning such specificity require molecular and cross-inoculation studies, using various strains of bacteria, and re-isolation after growth of the plants in different plant species. (203 words). © 2015, Springer International Publishing Switzerland.


Bashan Y.,Environmental Microbiology Group | Bashan Y.,The Bashan Institute of Science | Bashan Y.,Auburn University | Lopez B.R.,Environmental Microbiology Group | And 5 more authors.
Journal of Applied Phycology | Year: 2015

Molecular analyses employing sequencing of the complete ribosomal RNA cistron (18S rDNA, ITS1, 5.8S rDNA, ITS2, and 28S rDNA) and transcriptome analysis of the RuBisCO gene (rbcL) were done on Chlorella vulgaris UTEX 2714. The constructed phylogenetic trees showed that C. vulgaris UTEX 2714 is Chlorella sorokiniana. Growth analysis and production of chlorophyll a over a range of increasing cultivation temperatures (27–40 °C) showed that this strain is far less thermotolerant in comparison to a common C. sorokiniana strain. A change in the taxonomic designation of strain UTEX 2714 is proposed. © 2015 Springer Science+Business Media Dordrecht


Lopez-Lozano N.E.,Environmental Microbiology Group | Lopez-Lozano N.E.,San Luis Potosí Institute of Scientific Research and Technology | Carcano-Montiel M.G.,Autonomous University of Puebla | Bashan Y.,Environmental Microbiology Group | And 2 more authors.
Plant and Soil | Year: 2016

Background and aims: A major problem in all restoration and rehabilitation projects is to restore the function of the ecosystem. Nitrogen, next to water, is the most limiting factor for productivity of arid terrestrial ecosystems. Methods: We used a successful restored area, completed 10 years earlier, in comparison with an undisturbed scrubland area and a remaining, disturbed area in the southern Sonoran Desert in Baja California, Mexico. We compared the abundance of the nifH gene, estimated by qPCR, potential N2 fixation activity by acetylene reduction assay, and diversity of diazotrophs by denaturing gradient gel electrophoresis in the rhizosphere of the most representative plant species, the cardon cactus and the mesquite used for restoration. Results: The abundance of N2-fixing bacteria in the rhizosphere of cardon growing with mesquite had significantly higher abundance of nifH gene than the rhizosphere of cardon that grew separately. Across all samples, the potential N2 fixation was significantly higher in soil samples from the restored site than samples from the undisturbed and disturbed sites. Conclusions: Successful long-term restoration improved the potential N2 fixation to a level similar to undisturbed lands. Beneficial interactions between cardon and mesquite are a promising venue for desert reforestation by their contribution to improve N2 fixing potential in degraded arid lands and increasing the population of diazotrophs. © 2016 Springer International Publishing Switzerland


Meza B.,Environmental Microbiology Group | de-Bashan L.E.,Environmental Microbiology Group | de-Bashan L.E.,The Bashan Institute of Science | de-Bashan L.E.,Auburn University | And 5 more authors.
Research in Microbiology | Year: 2015

Accumulation of intra-cellular phosphate, as polyphosphate, was measured when the microalga Chlorella vulgaris was immobilized in alginate with either of two wild-type strains of the microalgae growth-promoting bacterium Azospirillum brasilense or their corresponding IAA-attenuated mutants. Wild type strains of A. brasilense induced higher amounts of intra-cellular phosphate in Chlorella than their respective mutants. Calculations comparing intra-cellular phosphate accumulation by culture or net accumulation by the cell and the amount of IAA that was produced by each of these strains revealed that higher IAA was linked to higher accumulations of intra-cellular phosphate. Application of four levels of exogenous IAA reported for A. brasilense and their IAA-attenuated mutants to cultures of C. vulgaris enhanced accumulation of intra-cellular phosphate; the higher the content of IAA per culture or per single cell, the higher was the amount of accumulated phosphate. When an IAA-attenuated mutant was complemented with exogenous IAA, accumulation of intra-cellular phosphate at the culture level was even higher than phosphate accumulation with the respective wild type strains. When calculating the net accumulation of intra-cellular phosphate in the complementation experiment, net intra-cellular phosphate induced by the IAA-attenuated mutant was completely restored and was similar to the wild strains. We propose that IAA produced by A. brasilense is linked to polyphosphate accumulation in C. vulgaris. © 2015 Institut Pasteur.Published by Elsevier Masson SAS.


Bacilio M.,Environmental Microbiology Group | Moreno M.,Environmental Microbiology Group | Bashan Y.,Environmental Microbiology Group | Bashan Y.,The Bashan Institute of Science | Bashan Y.,Auburn University
Applied Soil Ecology | Year: 2016

Humic acids and inoculation with the plant growth-promoting bacteria (PGPB) Pseudomonas stutzeri was used alone and combined to mitigate negative effects of progressive soil salinity gradients in a bell and a chili pepper. Plant height, length of root system, dry weight of stems, leaves and roots, number of leaves, leaf surface area, chlorophyll a and b content, total chlorophyll, and content of Na+, K+, Ca2+, and Mg2+ were measured in a salt-tolerant and a salt-susceptible pepper. We showed that applications of PGPB and humic acids did not have a clear-cut effect. Some plant parameters, such as leaf and root parameters, were positively affected at certain salinity gradients and others, such as plant height and number of leaves, did not. However, it appears that more positive effects by either treatment were more apparent in the salt-resistant cultivar. No synergism on plant growth parameters and salt mitigation was detected when humic acids and PGPB were applied together. The K+/Na+ and Ca2+/Na+ ratios showed that single applications of humic acids and the PGPB enhanced these ratios in several salinity regimes. More increases in these ratios were detected in the susceptible cultivar. In several salinity regimes, metabolic synergism, leading to enhancement of these ratios, was obtained when humic acids and the PGPB were applied together. In summary, under increased salt gradient, application of the PGPB or humic acids improved some plant growth parameters. Central to those are some improvements in the K+/Na+ and Ca2+/Na+ ratios. Combined application of PGPB and humic acids indicate a potential to use this strategy to combat salinity. © 2016 Elsevier B.V.


Posada L.F.,EAFIT University | Alvarez J.C.,EAFIT University | Hu C.-H.,Auburn University | de-Bashan L.E.,The Bashan Institute of Science | And 5 more authors.
Journal of Microbiological Methods | Year: 2016

Strains of Bacillus subtilis are plant growth-promoting bacteria (PGPB) of many crops and are used as inoculants. PGPB colonization is an important trait for success of a PGPB on plants. A specific probe, based on the 16 s rRNA of Bacillus subtilis, was designed and evaluated to distinguishing, by fluorescence in situ hybridization (FISH), between this species and the closely related Bacillus amyloliquefaciens. The selected target for the probe was between nucleotides 465 and 483 of the gene, where three different nucleotides can be identified. The designed probe successfully hybridized with several strains of Bacillus subtilis, but failed to hybridize not only with B. amyloliquefaciens, but also with other strains such as Bacillus altitudinis, Bacillus cereus, Bacillus gibsonii, Bacillus megaterium, Bacillus pumilus; and with the external phylogenetic strains Azospirillum brasilense Cd, Micrococcus sp. and Paenibacillus sp. The results showed the specificity of this molecular probe for B. subtilis. © 2016 Elsevier B.V.


Herrera H.,University of the Frontier | Valadares R.,Sustainable Development Technology | Contreras D.,Catholic University of the Maule | Bashan Y.,The Bashan Institute of Science | And 3 more authors.
Mycorrhiza | Year: 2016

Little is known about Orchidaceae plants in Chile and their mycorrhizal associations, a key issue for designing protective actions for endangered species. We investigated root fungi from seven terrestrial orchid species to identify potential mycorrhizal fungi. The main characteristics of Rhizoctonia-like fungi were observed under light microscopy, and isolates were identified through PCR-ITS sequencing. Molecular identification of fungal sequences showed a high diversity of fungi colonizing roots. Fungal ability to germinate seeds of different orchids was determined in symbiotic germination tests; 24 fungal groups were isolated, belonging to the genera Tulasnella, Ceratobasidium, and Thanatephorus. Furthermore, dark septate and other endophytic fungi were identified. The high number of Rhizoctonia-like fungi obtained from adult orchids from the Coastal mountain range suggests that, after germination, these orchids may complement their nutritional demands through mycoheterotrophy. Nonetheless, beneficial associations with other endophytic fungi may also co-exist. In this study, isolated mycorrhizal fungi had the ability to induce seed germination at different efficiencies and with low specificity. Germin ation rates were low, but protocorms continued to develop for 60 days. A Tulasnella sp. isolated from Chloraea gavilu was most effective to induce seed germination of different species. The dark septate endophytic (DSE) fungi did not show any effect on seed development; however, their widespread occurrence in some orchids suggests a putative role in plant establishment. © 2016 Springer-Verlag Berlin Heidelberg


PubMed | University Institute of La Paz, Environmental Microbiology Group and The Bashan Institute of Science
Type: Journal Article | Journal: Research in microbiology | Year: 2015

Accumulation of intra-cellular phosphate, as polyphosphate, was measured when the microalga Chlorella vulgaris was immobilized in alginate with either of two wild-type strains of the microalgae growth-promoting bacterium Azospirillum brasilense or their corresponding IAA-attenuated mutants. Wild type strains of A. brasilense induced higher amounts of intra-cellular phosphate in Chlorella than their respective mutants. Calculations comparing intra-cellular phosphate accumulation by culture or net accumulation by the cell and the amount of IAA that was produced by each of these strains revealed that higher IAA was linked to higher accumulations of intra-cellular phosphate. Application of four levels of exogenous IAA reported for A. brasilense and their IAA-attenuated mutants to cultures of C. vulgaris enhanced accumulation of intra-cellular phosphate; the higher the content of IAA per culture or per single cell, the higher was the amount of accumulated phosphate. When an IAA-attenuated mutant was complemented with exogenous IAA, accumulation of intra-cellular phosphate at the culture level was even higher than phosphate accumulation with the respective wild type strains. When calculating the net accumulation of intra-cellular phosphate in the complementation experiment, net intra-cellular phosphate induced by the IAA-attenuated mutant was completely restored and was similar to the wild strains. We propose that IAA produced by A. brasilense is linked to polyphosphate accumulation in C. vulgaris.


PubMed | Catholic University of the Maule, University of the Frontier, Sustainable Development Technology and The Bashan Institute of Science
Type: | Journal: Mycorrhiza | Year: 2016

Little is known about Orchidaceae plants in Chile and their mycorrhizal associations, a key issue for designing protective actions for endangered species. We investigated root fungi from seven terrestrial orchid species to identify potential mycorrhizal fungi. The main characteristics of Rhizoctonia-like fungi were observed under light microscopy, and isolates were identified through PCR-ITS sequencing. Molecular identification of fungal sequences showed a high diversity of fungi colonizing roots. Fungal ability to germinate seeds of different orchids was determined in symbiotic germination tests; 24 fungal groups were isolated, belonging to the genera Tulasnella, Ceratobasidium, and Thanatephorus. Furthermore, dark septate and other endophytic fungi were identified. The high number of Rhizoctonia-like fungi obtained from adult orchids from the Coastal mountain range suggests that, after germination, these orchids may complement their nutritional demands through mycoheterotrophy. Nonetheless, beneficial associations with other endophytic fungi may also co-exist. In this study, isolated mycorrhizal fungi had the ability to induce seed germination at different efficiencies and with low specificity. Germin ation rates were low, but protocorms continued to develop for 60days. A Tulasnella sp. isolated from Chloraea gavilu was most effective to induce seed germination of different species. The dark septate endophytic (DSE) fungi did not show any effect on seed development; however, their widespread occurrence in some orchids suggests a putative role in plant establishment.

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