Arbuscular mycorrhizal fungi activity in the rhizosphere of tree seedlings subjected to residual herbicides / Atividade de fungos micorrízicos arbusculares na rizosfera de mudas de árvores submetidas a herbicidas residuais

Trees occurring on the margins of agricultural areas can mitigate damage from residual herbicides. Rhizospheric microbial activity associated with trees is one of the main remedial capacity indicators. The objective of this study was to evaluate the rhizospheric microbiological activity in tree species subjected to the herbicides atrazine and sulfentrazone via the rhizosphere. The experiment was designed in four blocks and a 6 × 3 factorial scheme. The first factor consisted of six tree species from Brazil and the second of atrazine, sulfentrazone, and water solutions. Four herbicide applications were performed via irrigation. The total dry mass of the plants, mycorrhizal colonization, number of spores, basal respiration of the rhizospheric soil, and survival rate of bioindicator plants after phytoremediation were determined. Trichilia hirta had higher biomass when treated with atrazine and sulfentrazone. Herbicides decreased the microbial activity in Triplaris americana and did not affect the microbiological indicators of Myrsine gardneriana, Schizolobium parahyba, and Toona ciliata. Fewer bioindicator plants survived in soil with Triplaris americana and sulfentrazone. Microbiological indicators were influenced in different ways between species by the presence of herbicides in the rhizosphere.

As árvores que ocorrem nas margens das áreas agrícolas podem mitigar os danos dos herbicidas residuais. A atividade microbiana rizosférica associada às árvores é um dos principais indicadores de capacidade corretiva. O objetivo deste trabalho foi avaliar a atividade microbiológica rizosférica em espécies arbóreas submetidas aos herbicidas atrazina e sulfentrazone via rizosfera. O experimento foi estruturado em quatro blocos e esquema fatorial 6 × 3. O primeiro fator consistiu em seis espécies de árvores do Brasil e o segundo em soluções de atrazine, sulfentrazone e água. Quatro aplicações de herbicidas foram realizadas via irrigação. Foram determinados a massa seca total das plantas, colonização micorrízica, número de esporos, respiração basal do solo rizosférico e taxa de sobrevivência de plantas bioindicadoras após fitorremediação. Trichilia hirta apresentou maior biomassa quando tratada com atrazina e sulfentrazone. Os herbicidas diminuíram a atividade microbiana em Triplaris americana e não afetaram os indicadores microbiológicos de Myrsine gardneriana, Schizolobium parahyba e Toona ciliata. Menos plantas bioindicadoras sobreviveram no solo com Triplaris americana e sulfentrazone. Os indicadores microbiológicos foram influenciados de formas distintas entre as espécies pela presença dos herbicidas na rizosfera.

Characterization and cytotoxic activity on glial cells of alkaloid-enriched extracts from pods of the plants Prosopis flexuosa and Prosopis nigra (Fabaceae) / Caracterización, y actividad citotóxica en células gliales, de extractos enriquecidos con alcaloides de vainas de las plantas Prosopis flexuosa y Prosopis nigra (Fabaceae)

Introduction: Prosopis spp. pods have shown to be a potential source of protein and energy in livestock. However, prolonged ingestion of some of these species produces neurological symptoms in ruminants. Objective: In the present study, the alkaloid content and the in vitro neurotoxic activity of alkaloid enriched-extracts from P. flexuosa and P. nigra pods were determined in order to elucidate the mechanism of animal poisoning caused by these species. Methods: The main alkaloids present in both extracts were analysed by high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS). The cytotoxic activity of Prosopis alkaloid enriched-extracts in primary mixed glial cell culture was assessed by phase contrast microscopy and using neutral red, and lactate dehydrogenase (LDH) activity assays. Results: Juliprosine and juliprosopine were identified in P. flexuosa pods, while the absence of these alkaloids in P. nigra was confirmed. Both extracts (5-30 μg/mL) induced in a dose dependent manner, morphological alterations, such as swelling, enlargement and detachment from the culture surface. Consistent with this, decrease in cell viability and release of LDH 48 hours after exposure, revealed that P. flexuosa pods was significantly more cytotoxic than P. nigra. Conclusions: In P. flexuosa pods, juliprosine and juliprosopine alkaloids were identified for the first time. Moreover, the present study suggests that the cytotoxic effect displayed by both extracts is due to its alkaloid content. However, the presence of piperidine alkaloids in P. flexuosa could explain the greater cytotoxicity on glial cells with respect to P. nigra that was not shown to contain these alkaloids.

Introducción: Las vainas de diversas especies de Prosopis muestran ser una potencial fuente de proteínas y energía para el ganado. Sin embargo, la ingestión prolongada de algunas de estas especies produce síntomas neurológicos en los rumiantes. Objetivo: En el presente estudio se determinó el contenido de alcaloides y la actividad neurotóxica in vitro de los extractos enriquecidos con alcaloides obtenidos en las vainas de P. flexuosa y P. nigra, con el fin de dilucidar el mecanismo de la intoxicación animal causada por estas especies. Métodos: Los principales alcaloides presentes en ambos extractos se analizaron mediante cromatografía líquida de alto rendimiento-espectrometría de masas de alta resolución (HPLC-HRMS). La actividad citotóxica de los extractos enriquecidos con alcaloides de Prosopis se determinó en cultivos primarios de células gliales mixtas y se evaluó mediante microscopía de contraste de fase y utilizando ensayos de actividad de rojo neutro y de deshidrogenasa láctica (LDH). Resultados: Se identificaron la juliprosina y la juliprosopina en las vainas de P. flexuosa, mientras que se confirmó la ausencia de estos alcaloides piperidínicos en P. nigra. Ambos extractos (5-30 μg/mL) indujeron, de manera dependiente a la dosis, alteraciones morfológicas, como hinchazón, agrandamiento y desprendimiento de la superficie de cultivo. En consecuencia, la disminución de la viabilidad celular y la liberación de la LDH después de 48 horas de exposición, reveló que las vainas de P. flexuosa eran significativamente más citotóxicas que las de P. nigra. Conclusiones: El presente estudio muestra la presencia de los alcaloides juliprosina y juliprosopina en vainas de P. flexuosa y sugiere que el efecto citotóxico mostrado por ambos extractos se debe al contenido de alcaloides. Sin embargo, la presencia de estos alcaloides piperidínicos en P. flexuosa podría explicar la mayor citotoxicidad en las células gliales con respecto a P. nigra que no mostró que tuviera estos alcaloides.

Atividade antimicrobiana do óleo-resina de copaíba natural/comercial contra cepas padrão / Antimicrobial activity of natural/commercial copaiba oil-resin against standard strains / Actividad antimicrobiana de aceite-resina de copaiba natural/comercial contra cepas estándar

Objetivo: comparar laboratorialmente a atividade antimicrobiana de amostras do óleoresina de copaíba (Copaifera sp.) natural e comercial sobre as bactérias Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 25922 e Staphylococcus aureus ATCC 25923. Método: Trata-se de um estudo transversal descritivo ao qual utilizou-se a técnica de cilindro em placa além da determinação da concentração inibitória mínima do óleo em ágar Mueller-Hinton. Para o controle positivo foi utilizado solução de Hidróxido de Sódio e para o controle negativo, solução fisiológica de Cloreto de Sódio. Resultados: o óleo de copaíba natural e comercial apresentou potencial de inibição do crescimento bacteriano satisfatório sobre as cepas Staphylococcus aureus ATCC 25923 e Escherichia coli ATCC 25922, sendo a bactéria Pseudomonas aeruginosa ATCC 9027 resistente ao óleo na concentração de 150µL da solução. A atividade antimicrobiana variou de acordo com os óleos e os patógenos estudados; nas concentrações de 100% até 3,1% houve inibição da cepa Escherichia coli ATCC 25922 e de 100% a 25% da cepa Staphylococcus aureus ATCC 25923, em ambos os óleos de copaíba. Conclusão: o óleo de copaíba natural e comercial possuem diferenças mínimas no potencial de inibição para os específicos patógenos. No entanto, Escherichia coli ATCC 25922 foi mais sensível que Staphylococcus aureus ATCC 25923, tanto no óleo-resina natural quanto comercial.(AU)

Objective: to compare the antimicrobial activity of natural and commercial copaíba (Copaifera sp.) oil-resin samples on the bacterias Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923. Method: this is a descriptive cross-sectional study analysis to which the plate cylinder technique was used in addition to the determination of the minimum inhibitory concentration of the oil in Mueller-Hinton agar. For the positive control it was used a sodium hydroxide solution and for the negative control, a physiological sodium chloride solution. Results: commercial and natural copaiba oil showed satisfactory bacterial growth inhibition on Staphylococcus aureus strains ATCC 25923 and Escherichia coli ATCC 25922, with the bacterium Pseudomonas aeruginosa ATCC 9027 being resistant to oil in the concentration of 150 µL of the solution. The antimicrobial activity varied according to the oils and pathogens studied; at concentrations of 100% to 3.1% there was inhibition of the Escherichia coli strain ATCC 25922 and 100% to 25% of Staphylococcus aureus strain ATCC 25923 in both copaiba oils. Conclusion: natural and commercial copaiba oil have minimal differences in the potential for inhibition of specific pathogens. However, Escherichia coli ATCC 25922 was more sensitive than Staphylococcus aureus ATCC 25923, both in the natural and commercial oil-resin.(AU)

Objetivo: comparar la actividad antimicrobiana del aceite de Copaíba natural y comercial (Copaifera sp.) en muestras de Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 25922 y Staphylococcus aureus ATCC 25923. Método: estudio transversal, descriptivo, que se usó la técnica de cilindro en la determinación de la placa y también la concentración mínima de aceite en Mueller-Hinton. Para control positivo, usó la solución de hidróxido de sodio y lo control negativo, solución fisiológica de clorhidrato de sodio. Resultados: el aceite de copaíba, natural y comercial, tiene el potencial de inhibir el crecimiento bacteriano en las cepas Staphylococcus aureus ATCC 25923 y Escherichia coli ATCC 25922, que es resistente a la Pseudomonas aeruginosa ATCC 9027 resistente al aceite a una concentración de 150 µl de solución. La actividad antimicrobiana varió de acuerdo con las concentraciones del aceite y patógenos estudiados; En las concentraciones de 100% a 3.1% hubo inibición da cepa Escherichia coli ATCC 25922 e del 100% al 25% de la cepa Staphylococcus aureus ATCC 25923, en ambos aceites de copaiba. Conclusión: el aceite de copaíba, natural y comercial, tiene mínimas diferencias em su potencial de inhibición para patógenos específicos. Sin embargo, Escherichia coli ATCC 25922 es más sensible que el Staphylococcus aureus ATCC 25923, no tanto como la resina de aceite natural comercial.(AU)

Genomic comparisons of Rhizobium species using in silico AFLP-PCR, endonuclease restriction, and AMPylating enzymes

Background: The whole-genome sequences of nine Rhizobium species were evaluated using different in silico molecular techniques such as AFLP-PCR, restriction digest, and AMPylating enzymes. The entire genome sequences were aligned with progressiveMauve and visualized by reconstructing phylogenetic tree using NTSYS pc 2.11X. The "insilico.ehu.es" was used to carry out in silico AFLP-PCR and in silico restriction digest of the selected genomes. Post-translational modification (PTM) and AMPylating enzyme diversity between the proteome of Rhizobium species were determined by novPTMenzy. Results: Slight variations were observed in the phylogeny based on AFLP-PCR and PFGE and the tree based on whole genome. Results clearly demonstrated the presence of PTMs, i.e., AMPylation with the GS-ATasE (GlnE), Hydroxylation, Sulfation with their domain, and Deamidation with their specific domains (AMPylating enzymes) GS-ATasE (GlnE), Fic, and Doc (Phosphorylation); Asparagine_hydroxylase and Collagen_prolyl_lysyl_hydroxylase; Sulfotransferase; and CNF (Cytotoxic Necrotizing Factors), respectively. The results pertaining to PTMs are discussed with regard to functional diversities reported in these species. Conclusions: The phylogenetic tree based on AFLP-PCR was slightly different from restriction endonuclease- and PFGE-based trees. Different PTMs were observed in the Rhizobium species, and the most prevailing type of PTM was AMPylation with the domain GS-ATasE (GlnE). Another type of PTM was also observed, i.e., Hydroxylation and Sulfation, with the domains Asparagine_hydroxylase and Collagen_prolyl_lysyl_hydroxylase and Sulfotransferase, respectively. The deamidation type of PTM was present only in Rhizobium sp. NGR234. How to cite: Qureshi MA, Pervez MT, Babar ME, et al. Genomic comparisons of Rhizobium species using in silico AFLP-PCR, endonuclease restrictions and ampylating enzymes.

Phytochemistry and antibacterial activity of aqueous andhydroalcoholic extracts of three medicinal plants against foodpathogens / Fitoquímica e atividade antibacteriana de extratos aquosos e hidroalcoólicos de trêsplantas medicinais contra patógenos de alimentos

This study aimed to characterize the phytochemical compositions of three medicinal Brazilian plants’ leaves and bast extracts, and to determine their antibacterial activity on three foodborne and waterborne bacterial pathogens. Parkia platycephala, Pouteria ramiflora and Lophanthera lactescens leaves and basts were collected and aqueous and hydroalcoholic extracts were prepared. Qualitative screening of the phytochemical extracts was performed with three replicates and in triplicate in order to identify the bioactive compounds. The Minimal Inhibitory Concentration and Minimal Bactericide Concentration were determined by microdilution in broth and Escherichia coli, Salmonella typhimurium and Staphylococcus aureus growth was observed on agar plates. Phytochemical composition analysis allowed for the identification of anthraquinones, catechins, saponins, tannins, sesquiterpenlactones and other lactones in the three plants’ leaves and bast aqueous and hydroalcoholic extracts. Eighty-three percent of the plant extracts showed antibacterial activity against S. aureus, and P. platycephala extracts were the only ones that inhibited E. coli and S. typhimurium growth. The present study contributes significantly to the phytochemical composition characterization of three plant species commonly used in Brazilian traditional medicine. The plant extracts’ in vitro antibacterial activity was demonstrated and catechins present in the extracts are, most likely, the bioactive compounds responsible for this action.

Este estudo objetivou caracterizar a composição fitoquímica dos extratos de folhas e das entrecascas de três plantas medicinais brasileiras e determinar a sua atividade antimicrobiana contra três patógenos bacterianos de alimentos. Foram elaborados extratos aquosos e hidroalcoólicos, por meio de folhas e de entrecascas de Parkiaplatycephala, Pouteriaramiflora e Lophantheralactescens. O estudo qualitativo dos extratos foi realizado com três réplicas, em triplicata, para permitir a identificação dos compostos bioativos. A Concentração Inibitória Mínima e a Concentração Bactericida Mínima foram determinadas por microdiluição contra Escherichia coli, Salmonella typhimurium e Staphylococcus aureus. A análise da composição fitoquímica permitiu identificar antraquinonas, catequinas, saponinas, taninas, sesquiterpenlactonas e outras lactonas nos extratos aquosos e hidroalcoólicos das folhas e das entrecascas das três plantas. Oitenta e três porcento dos extratos das plantas apresentaram atividade antibacteriana contra S. aureus. Os extratos de P. platycephala foram os únicos que inibiram o crescimento de E. coli e S. typhimurium. Este estudo contribui significativamente para a caracterização da composição fitoquímica de três espécies de plantas, frequentemente, utilizadas na medicina tradicional brasileira. A atividade antibacteriana, in vitro, dos extratos das plantas foi demonstrada, e as catequinas são, provavelmente, o composto bioativo responsável por essa atividade.

Burkholderia species associated with legumes of Chiapas, Mexico, exhibit stress tolerance and growth in aromatic compounds / Especies de Burkholderia asociadas a leguminosas de Chiapas, México exhiben tolerancia a estrés y crecimiento en compuestos aromáticos

Leguminous plants have received special interest for the diversity of β-proteobacteria in their nodules and are promising candidates for biotechnological applications. In this study, 15 bacterial strains were isolated from the nodules of the following legumes: Indigofera thibaudiana, Mimosa diplotricha, Mimosa albida, Mimosa pigra, and Mimosa pudica, collected in 9 areas of Chiapas, Mexico. The strains were grouped into four profiles of genomic fingerprints through BOX-PCR and identified based on their morphology, API 20NE biochemical tests, sequencing of the 16S rRNA, nifH and nodC genes as bacteria of the Burkholderia genus, genetically related to Burkholderia phenoliruptrix, Burkholderia phymatum, Burkholderia sabiae, and Burkholderia tuberum. The Burkholderia strains were grown under stress conditions with 4% NaCl, 45°C, and benzene presence at 0.1% as the sole carbon source. This is the first report on the isolation of these nodulating species of the Burkholderia genus in legumes in Mexico.

Las plantas leguminosas han recibido especial interés por la diversidad de β-proteobacteria que albergan en sus nodulos; algunas de estas bacterias son candidatas prometedoras para aplicaciones biotecnológicas. En el presente trabajo se aislaron 15 cepas bacterianas de los nodulos de las leguminosas Indigofera thibaudiana, Mimosa diplotricha, Mimosa albida, Mimosa pigra y Mimosa púdica, colectadas en 9 áreas de Chiapas, México. Las cepas fueron agrupadas en 4 perfiles de huellas genómicas por BOX-PCR e identificadas sobre la base de su morfología, pruebas bioquímicas API 20NE y secuenciación de los genes 16S ARNr, nifH y nodC como bacterias del género Burkholderia relacionadas genéticamente con Burkholderia phenoliruptrix, Burkholderia phymatum, Burkholderia sabiae y Burkholderia tuberum. Las cepas de Burkholderia crecieron en condiciones de estrés con NaCl al 4%, a una temperatura de 45°C y en presencia de benceno al 0,1% como única fuente de carbono. Este es el primer reporte del aislamiento de especies de Burkholderia nodulantes en leguminosas en México.

Genome sequence of Bradyrhizobium embrapense strain CNPSo 2833T, isolated from a root nodule of Desmodium heterocarpon

Abstract Bradyrhizobium embrapense CNPSo 2833T is a nitrogen-fixing symbiont of the legume pasture Desmodium. Its draft genome contains 8,267,832 bp and 7876 CDSs. The symbiotic island includes nodulation and nitrogen fixation genes resembling the operon organization of B. japonicum. Several CDSs related to secretion proteins and stress tolerance were also identified.

Nitrogen-fixing bacteria and arbuscular mycorrhizal fungi in Piptadenia gonoacantha ( Mart. ) Macbr

Abstract The family Leguminosae comprises approximately 20,000 species that mostly form symbioses with arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing bacteria (NFB). This study is aimed at investigating and confirming the dependence on nodulation and biological nitrogen fixation in the specie Piptadenia gonoacantha (Mart.) Macbr., which belongs to the Piptadenia group. Two consecutive experiments were performed in a greenhouse. The experiments were fully randomized with six replicates and a factorial scheme. For the treatments, the two AMF species and three NFB strains were combined to nodulate P. gonoacantha in addition to the control treatments. The results indicate this species’ capacity for nodulation without the AMF; however, the AMF + NFB combinations yielded a considerable gain in P. gonoacantha shoot weight compared with the treatments that only included inoculating with bacteria or AMF. The results also confirm that the treatment effects among the AMF + NFB combinations produced different shoot dry weight/root dry weight ratios. We conclude that AMF is not necessary for nodulation and that this dependence improves species development because plant growth increases upon co-inoculation.

Molecular diagnosis and intraspecific genetic variability of root pathogens of arid legumes in Western Rajasthan, India / Diagnóstico molecular y la variabilidad genética intraespecífica de patógenos de raíces en leguminosas resistentes a sequías del oeste de Rajasthan, India

Abstract:The productivity of arid legumes, such as Clusterbean (Cyamopsis tetragonoloba), Cowpea (Vigna unguiculata), Moth bean (Vigna aconitifolia) and Horse gram (Macrotyloma uniflorum), may remain stagnant over decades because of their high susceptibility to root diseases. Besides, there is a limitation on the information about molecular diagnosis and intraspecific genetic variability of root pathogens in arid legumes. To contribute in this field, we assessed a total of 52 isolates from 88 root samples that were found infected with fungal pathogens in Jodhpur, Jaipur and Bikaner Districts of Rajasthan. Diseased roots samples were analyzed following standard microbiological methods for fungus extraction and purification, and for genetic studies. Irrespective of the geographical location from where the diseased samples were collected, all pathogen isolates were clustered in RAPD dendrograms as per their respective genera. Phylogram, based on multiple sequence alignment, revealed that different genera (i.e. Fusarium, Neocosmospora and Syncephalastrum), separated from each other, and species within the same genera, clustered together with their reference sequences with apreciable bootstrap values. Out of 20 representative isolates representing each cluster and all outgroups sequenced, eight were molecularly identified as Neocosmospora vasinfecta, five as Fusarium solani, two as Neocosmospora striata, two as Fusarium acutatum, one as Syncephalastrum monosporum, one as Fusarium oxysporum and one as Fusarium species. The root pathogens of the arid legumes were found neither restricted to a geographical location nor were host specific in nature. Fusarium solani wilt in cowpea and seedling rot in moth bean, F. oxysporum wilt in moth bean, F. acutatum damping off in cowpea and Clusterbean, Fusarium sp. seedling rot in Clusterbean, Neocosmospora striata root rot in cowpea and wilt in Clusterbean and Syncephalastrum monosporum root rot in Clusterbean were molecularly identified as new fungal records as pathogens causing root diseases in arid legumes. Rev. Biol. Trop. 64 (4): 1505-1518. Epub 2016 December 01.

Resumen:La producción de leguminosas resistentes a sequías como Cyamopsis tetragonoloba, Vigna unguiculata, Vigna aconitifolia y Macrotyloma uniflorum, puede permanecer inactiva durante décadas debido a su alta susceptibilidad a enfermedades en las raíces. Además, hay información limitada relacionada con el diagnóstico molecular y la variabilidad genética intraespecífica de patógenos de raíces en estas leguminosas resistentes a sequías. Para contribuir en esta área, evaluamos un total de 52 extractos de 88 raíces infectadas con patógenos fúngicos en los distritos de Jodhpur, Jaipur y Bikaner de Rajastán. Las muestras de raíces infectadas se analizaron siguiendo los métodos estándar de microbiología para extracción y purificación de hongos y para estudios genéticos. Independientemente del sitio donde se recolectaron las muestras contaminadas, todos los extractos patógenicos se agruparon en dendrogramas RAPD en cada uno de sus respectivos géneros. El filograma, basado en alineamiento de secuencias múltiples reveló que distintos géneros (Fusarium, Neocosmospora y Syncephalastrum) separados entre ellos y especies del mismo género se agrupan con sus secuencias de referencia con valores de bootstrap significativos. De cada 20 extractos representantes de cada agrupamiento y todos los grupos externos secuenciados, ocho fueron identificados molecularmente como Neocosmospora vasinfecta, dos como Fusarium acutatum, una como Syncephalastrum monosporum, una como Fusarium oxysporum y una como Fusarium. Los patógenos de estas leguminosas resistentes a sequías no están restringidos por la localidad ni por un hospedero específico. Fusarium solani que marchita el frijol de vaca y pudre la semilla de Vigna aconitifolia, F. oxysporum que marchita a Vigna aconitifolia, F. acutatum que marchita a Vigna unguiculata y Cyamopsis tetragonoloba, Fusarium sp. que pudre la semilla de Cyamopsis tetragonoloba, Neocosmospora striata que pudre la raíz de Vigna unguiculata y marchita a Cyamopsis tetragonoloba y, Syncephalastrum monosporum que pudre la raíz en Cyamopsis tetragonoloba, fueron identificados molecularmente como nuevos registros de patógenos fúngicos que causan daños en las raíces de leguminosas resistentes a sequías.

Initial pH of medium affects organic acids production but do not affect phosphate solubilization

The pH of the culture medium directly influences the growth of microorganisms and the chemical processes that they perform. The aim of this study was to assess the influence of the initial pH of the culture medium on the production of 11 low-molecular-weight organic acids and on the solubilization of calcium phosphate by bacteria in growth medium (NBRIP). The following strains isolated from cowpea nodules were studied: UFLA03-08 (Rhizobium tropici), UFLA03-09 (Acinetobacter sp.), UFLA03-10 (Paenibacillus kribbensis), UFLA03-106 (Paenibacillus kribbensis) and UFLA03-116 (Paenibacillus sp.). The strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 solubilized Ca3(PO4)2 in liquid medium regardless of the initial pH, although without a significant difference between the treatments. The production of organic acids by these strains was assessed for all of the initial pH values investigated, and differences between the treatments were observed. Strains UFLA03-09 and UFLA03-10 produced the same acids at different initial pH values in the culture medium. There was no correlation between phosphorus solubilized from Ca3(PO4)2 in NBRIP liquid medium and the concentration of total organic acids at the different initial pH values. Therefore, the initial pH of the culture medium influences the production of organic acids by the strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 but it does not affect calcium phosphate solubilization.

Sourcing Starter Cultures for Parkia biglobosa Fermentation Part II: Potential of Bacillus subtilis Strains.

Aim: To select good strains of Bacillus subtilis for use as starter culture in the fermentation of Parkia biglobosa. Study Design: Fifteen (15) strains of Bacillus subtilis group obtained from commercial samples were used in starter-culture fermentation of Parkia biglobosa seeds to produce ‘iru’. Place and Duration of Study: Food Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), Pahumthani, Thailand, between March to May 2010. Methodology: The quality of the starter culture-fermented products were compared on the bases of sensory evaluation, degree of hydrolysis (DH), level of ammonia nitrogen (NH3-N), pH and enzymatic activities. The 15 strains were also screened for haemolytic activity. Results: On the basis of the sensory scores of 5 parameters (color, odor, consistency, texture and over-all liking), particularly the over-all liking, 5 strains were rated the best (in descending order): BC4333 > 8B > 2B > 7A > 5A, amongst the 15 tested. There were good correlations between pH and DH (r= 0.926), DH and NH3-N (r=0.962) and between pH and NH3-N (r=0.945). The strain BC4333 produced the very soft variant of ‘iru’ (‘iru-pete’), without the addition of ‘kuuru’ (local potash). The quantity of extracellular enzymes (protease, amylase, pectinase, phytase and lipase) produced during fermentation varied significantly. None of the 5 strains was haemolytic on sheep blood agar. Conclusion: The 5 strains of Bacillus subtilis (BC4333, 8B, 2B, 7A, 5A) that showed potentials of being used as starter cultures for industrial production of ‘iru’, were nonhemolytic on blood agar.

Effectiveness of halo-tolerant, auxin producing Pseudomonas and Rhizobium strains to improve osmotic stress tolerance in mung bean (Vigna radiata L.)

Halo-tolerant, auxin producing bacteria could be used to induce salt tolerance in plants. A number of Rhizobium and auxin producing rhizobacterial strains were assessed for their ability to tolerate salt stress by conducting osmoadaptation assay. The selected strains were further screened for their ability to induce osmotic stress tolerance in mung bean seedlings under salt-stressed axenic conditions in growth pouch/jar trials. Three most effective strains of Rhizobium and Pseudomonas containing ACC-deaminase were evaluated in combination, for their ability to induce osmotic stress tolerance in mung bean at original, 4, and 6 dS m-1 under axenic conditions. Results showed that sole inoculation of Rhizobium and Pseudomonas strains improved the total dry matter up to 1.4, and 1.9 fold, respectively, while the increase in salt tolerance index was improved up to 1.3 and 2.0 fold by the Rhizobium and Pseudomonas strains, respectively. However, up to 2.2 fold increase in total dry matter and salt tolerance index was observed due to combined inoculation of Rhizobium and Pseudomonas strains. So, combined application of Rhizobium and Pseudomonas strains could be explored as an effective strategy to induce osmotic stress tolerance in mung bean.

In vivo Evaluation of Hypolipidemic Potentials of Bacillus Species Isolated from Fermented Locust Bean (Parkia fillicoides Welw) Seeds (Iru).

Aim: Iru is a popular West Africa fermented soup condiment which is also consumed without cooking as snack. This product is mainly fermented by Bacillus species. The hypolipidemic activities of Bacillus spp. isolated from iru have not been documented hence the aim of this study. Place and Duration of Study: Iru sample was bought in an open market in Iworoko-Ekiti, Nigeria and transferred to the Laboratory of the Department of Microbiology, Ekiti State University, Nigeria where other studies were carried out. The study was conducted between January and June, 2012. Methodology: The properties and in vivo hypolipidemic potential of Bacillus species from iru were investigated using standard microbiological and haematological methods. Results: The cell free extracts of the Bacillus spp. did not produce significant inhibition on the selected Gram positive and Gram negative pathogens. Qualitative enzyme screening of the isolates showed all were haemolysin negative. Only B. subtilis was positive to gelatinase while all the isolates produced catalase and lipase. The average weight of the animals after inducement of hyper-cholesterolemia ranged between 60.5g - 95.3g. The amount of serum total cholesterol (TC) in the animals ranged between 124.9 mg/dl – 127.4 mg/dl while that of serum triglycerides (TG), high density protein (HDL) and low density protein (LDL) were 122.5 – 155.3 mg/dl, 10.0 – 15.3 mg/dl and 76.6 – 81.0 mg/dl respectively. The weights of hyper-cholesterolemia induced rats challenged with different species of Bacillus were relatively lower than those in the control group and also differ significantly from the control, at p˂ 0.05. The values of TC, TG, and LDL were highest in the control (saline) group while the values in the treatment group ranged between 121.3 ± 1.5 and 102.3 ± 6.8 mg/dl for TC. The treatment groups recorded lower values of values for TG (104.7 ± 1.6 - 117.4 ± 9.1 mg/dl) and LDL (42.6 ±7.4 - 59.0 ± 10.2 mg/dl) compared to the control. B. subtilis had the highest values of TC but least amount of LDL. TG in all the groups was higher than TC, HDL and LDL. The TC/HDL and the LDL/HDL of the animals in the iru group was higher than the other treatment groups but lower than the control. Conclusion: Compared to the control, hypolipidemic activities of B. lichenliformis was the best followed by B. subtilis. Iru had the least hypo-cholesterolemic effect.

Ochratoxin a concentrations in some grain and bean commodities for human feed

In order to determine the concentration levels of the mucotoxin Ochratoxin A [OTA] in human food commodities in Damascus, 13 different samples of almonds, cashew nuts, peanuts, walnuts, hazelnuts, pine nuts, roasted pistachio nuts, wheat, beans, broad beans, lentils, maize, and chickpea were collected from the retail market of Damascus. After grinding and homogenizing of each sample separately, fatty stuff in oily nuts was extactated three times successively by hexan [10 gm of homogenate extracted by 15 ml of the organic solevant] and the fatty suprenatents was discarded. Mycotoxins were extracted from each homogenate [l0gm] by a mixture of acetonetryl and double-distilled-double deionized water [80V/20V]. The extraction procedure was repeated three times. This led to the extraction of OTA, aflatoxin Bl [AF Bl], and zeralonon [ZEN]. The third precipitate was also extracted three times by acetonetryl water [50V/50V] to extract OTA and other mycotoxins, especially deoxynivalenol [DON] and fumonizine Bl [FBI]. Fluorescence HPLC column and monitor was validated. The column was injected with 90 micro l of each extract. The flow rat was 1ml/min under pressure of 14.3 atmospheres, with an excitation at 340 nm and emission at 465 nm. Values of OTA were graphically represented. The highest concentration was found in the peanuts [29.8 micro g/kg], and the lowest in the chickpea [5.1 micro g/kg]. The international consensus of permissible and tolerated concentration in human feeds is 2-4 micro g/kg

11th International Congress on Molecular Plant-Microbe Interactions held at St. Petersburg--a report.

The report is a short summary of the most interesting presentations at the 11th International Congress on Molecular Plant-Microbe Interactions held during July 18-27, 2003 at St. Petersburg, Russia. The key elements from several sessions on the legume-Rhizobium interactions have been discussed.

Effects of drought stress on legume symbiotic nitrogen fixation: physiological mechanisms.

Drought stress is one of the major factors affecting nitrogen fixation by legume-rhizobium symbiosis. Several mechanisms have been previously reported to be involved in the physiological response of symbiotic nitrogen fixation to drought stress, i.e. carbon shortage and nodule carbon metabolism, oxygen limitation, and feedback regulation by the accumulation of N fixation products. The carbon shortage hypothesis was previously investigated by studying the combined effects of CO2 enrichment and water deficits on nodulation and N2 fixation in soybean. Under drought, in a genotype with drought tolerant N2 fixation, approximately four times the amount of 14C was allocated to nodules compared to a drought sensitive genotype. It was found that an important effect of CO2 enrichment of soybean under drought was an enhancement of photo assimilation, an increased partitioning of carbon to nodules, whose main effect was to sustain nodule growth, which helped sustain N2 rates under soil water deficits. The interaction of nodule permeability to O2 and drought stress with N2 fixation was examined in soybean nodules and led to the overall conclusion that O2 limitation seems to be involved only in the initial stages of water deficit stresses in decreasing nodule activity. The involvement of ureides in the drought response of N2 fixation was initially suspected by an increased ureide concentration in shoots and nodules under drought leading to a negative feedback response between ureides and nodule activity. Direct evidence for inhibition of nitrogenase activity by its products, ureides and amides, supported this hypothesis. The overall conclusion was that all three physiological mechanisms are important in understanding the regulation of N2 fixation and its response of to soil drying.

Recent advances in Rhizobium-legume symbiosis.

The research findings in the field of Rhizobium-legume symbiosis reported worldwide during the years 2002 and 2003 (up to September) have been summarized. The information is presented under the various topics, viz., isolation and characterization of rhizobial strains, physiological aspects of nitrogen fixation, rhizosphere interactions and root surface signals, genomics and proteomics, plant genes involved in nodule formation, bioremediation and biocontrol, and review articles and conference reports. The postal and e-mail addresses of the concerned scientists have also been included.

Growth behaviour and bioproduction of indole acetic acid by a Rhizobium sp. isolated from root nodules of a leguminous tree Dalbergia lanceolaria.

The Rhizobium sp. isolated from healthy and mature root nodules of a leguminous tree, Dalbergia lanceolaria Linn. f., preferred mannitol and KNO3 for growth as carbon and nitrogen sources, respectively. The bacterium produced a high amount (22.3 microg/ml) of indole acetic acid (IAA) from L-tryptophan supplemented basal medium. Growth and IAA production started simultaneously. IAA production was maximum at 20 hr when the bacteria reached the stationary phase of growth. Cultural requirements were optimized for maximum growth and IAA production. The IAA production by the Rhizobium sp. was increased by 270.8% over control when the medium was supplemented with mannitol (1%,w/v), SDS (1 microg/ml), L-asparagine (0.02%,w/v) and biotin (1 microg/ml) in addition to L-tryptophan (2.5 mg/ml). The possible role of IAA production in the symbiosis is discussed.

Lipochitooligosaccharides and legume Rhizobium symbiosis--a new concept.

Legume-Rhizobium symbiosis is a multistep process characterized by the formation of root nodules on the host plant. A number of genes from both symbiotic partners share information during the interaction process. Nodulation genes (nod, nol and noe) have been classified as common nodulation genes and host specific (hsn) nodulation genes. Though common nodulation genes are enough to form root nodules, host specific nodulation genes are needed for specific interaction leading to formation of functional nodules. Core lipochitooligosaccharides (LCOs), the products of common nodulation genes are modified by the action of host specific nodulation genes. LCOs seem to be present in legumes as well as nonlegume and are known to act as a morphogen by acting as auxin-transport inhibitor. The understanding of Nod factor may contribute to reveal complex biological functions such as developmental regulation, signal transduction and plant morphogenesis.