Essential oils in the management of soft rot of kale in the brazilian semiarid region / Óleos essenciais no manejo da podridão mole em couve no semiárido brasileiro

The aim of this study was to analyze the effect of essential oils on the control of soft rot of kale. Clove essential oil at 0.25%, lemongrass and palmarosa essential oils at 0.5%, melaleuca and orange essential oils at 0.75%, bergamot, rosemary, sage and ginger essential oils at 1% were evaluated for the in vitro inhibition of Pectobacterium carotovorum subsp. brasiliensis (Pcb) and control of soft rot of kale, sprayed 72 hours before or seven hours after inoculation. Clove, citronella, bergamot, rosemary, palmarosa, sage, melaleuca, and lemongrass oils completely inhibited the growth of Pcb. Lemongrass oil (0.5%) caused 0% of disease incidence (INC), providing 100% of disease control in both periods of inoculation. Clove oil (0.25%) showed a lower INC (25%) when applied after inoculation, providing a control percentage of 71.42%. The lemongrass and clove essential oils were analyzed by GC/FID (Gas Chromatography ­ Flame Ionization Detector) and by GC/MS (Gas Chromatography /Mass Spectrometer). The major components were eugenol (91,9%) for clove oil and citral, isometric mixture of neral (34,1%) and geranial (42,9%) for lemongrass oil. The Minimum inhibitory concentration (MIC) of lemongrass, clove oils and their major components (citral and eugenol, respectively) was determined by using a broth macrodilution technique, as well as they were evaluated at different concentrations on the control of soft rot of kale, sprayed according descriptions above. The MIC was 0.03125% for citral, and 0.0625 and 0.125% for lemongrass and clove oils, respectively. Eugenol didn't show MIC. Lemongrass oil at 0.125% (post-inoculation) and citral at 0.125% (pre and post-inoculation) provided the highest percentages of disease control (33.33, 50, and 100%, respectively). Clove oil at 0.125% (post-inoculation) showed better effectiveness than eugenol (0.25%), providing a percentage of disease control of 16.67%. Lemongrass and clove essential oils were the most effective in control of soft rot of kale, suggesting that these oils have a potential to be used as antibacterial agents.

O objetivo do estudo foi avaliar o efeito de óleos essenciais no controle da podridão mole em couve. Os óleos essenciais de cravo a 0,25%, capim-limão e palmarosa a 0,5%, citronela, melaleuca e laranja a 0,75%, bergamota, alecrim, sálvia e gengibre a 1% foram avaliados na inibição in vitro de Pectobacterium carotovorum subsp. brasiliensis (Pcb) e controle da podridão mole em couve, pulverizados 72 horas antes ou sete horas após a inoculação. Os óleos essenciais de cravo, citronela, bergamota, alecrim, palmarosa, sálvia, melaleuca e capim-limão inibiram completamente o crescimento de Pcb. O óleo de capimlimão (0,5%) promoveu 0% de incidência (INC) da doença (percentual de controle de 100%), em ambos os períodos de inoculação. O óleo de cravo (0,25%) proporcionou menor INC (25%) quando aplicado após inoculação (percentual de controle de 71,42%). Os óleos essenciais de capim-limão e cravo foram analisados por GC/FID (cromatografia gasosa/detector por ionização de chama) e por GC/MS (cromatografia gasosa/ espectometria de massas). Os componentes majoritários foram eugenol (91,9%) no óleo de cravo e citral (neral34,1% e geranial- 42,9%) no óleo de capim-limão. A concentração inibitória mínima (CIM) dos óleos essenciais de capim-limão e cravo e de seus componentes majoritários (citral e eugenol, respectivamente) foi determinada por meio da técnica de macrodiluição em caldo, bem como foram avaliados, em diferentes concentrações, no controle da podridão mole em couve, pulverizados conforme descrito acima. A concentração inibitória mínima (CIM) foi de 0,03125% para o citral, e de 0,0625 e 0,125% para os óleos de capim-limão e cravo, respectivamente. O eugenol não apresentou CIM. O óleo de capim-limão a 0,125% (pós-inoculação) e o citral (0,125%), em ambos os períodos de inoculação, proporcionaram os maiores percentuais de controle (33,33; 50 e 100%, respectivamente). O óleo de cravo a 0,125% (pós-inoculação) mostrou maior eficiência que o eugenol (0,25%), promovendo um percentual de controle de 16,67%. Os óleos essenciais de capim-limão e cravo destacaram-se na eficiência de controle da podridão mole em couve, sugerindo que esses óleos têm potencial para serem utilizados como agentes antibacterianos.

Antiproliferative activity of biomass extract from Pseudomonas cedrina

Background: The study of plant-associated microorganisms is very important in the discovery and development of bioactive compounds. Pseudomonas is a diverse genus of Gammaproteobacteria comprising more than 60 species capable of establishing themselves in many habitats, which include leaves and stems of many plants. There are reports of metabolites with diverse biological activity obtained from bacteria of this genus, and some of the metabolites have shown cytotoxic activity against cancer cell lines. Because of the high incidence of cancer, research in recent years has focused on obtaining new sources of active compounds that exhibit interesting pharmacodynamic and pharmacokinetic properties that lead to the development of new therapeutic agents. Results: A bacterial strain was isolated from tumors located in the stem of Pinus patula, and it was identified as Pseudomonas cedrina. Extracts from biomass and broth of P. cedrina were obtained with chloroform:methanol (1:1). Only biomass extracts exhibited antiproliferative activity against human tumor cell lines of cervix (HeLa), lung (A-549), and breast (HBL-100). In addition, a biomass extract from P. cedrina was fractioned by silica gel column chromatography and two diketopiperazines were isolated: cyclo-(L-Prolyl-L-Valine) and cyclo-(L-Leucyl-L-Proline). Conclusions: This is the first report on the association of P. cedrina with the stems of P. patula in Mexico and the antiproliferative activity of extracts from this species of bacteria against human solid tumor cell lines.

Archaea diversity in vegetation gradients from the Brazilian Cerrado

Abstract We used 16S rRNA sequencing to assess the archaeal communities across a gradient of Cerrado. The archaeal communities differed across the gradient. Crenarcheota was the most abundant phyla, with Nitrosphaerales and NRPJ as the predominant classes. Euryachaeota was also found across the Cerrado gradient, including the classes Metanocellales and Methanomassiliicoccaceae.

Klebsiella variicola and Klebsiella quasipneumoniae with capacity to adapt to clinical and plant settings / Klebsiella variicola y Klebsiella quasipneumoniae con capacidad para adaptarse al ambiente clínico y a las plantas

Abstract: Objective: To compare the genetic determinants involved in plant colonization or virulence in the reported genomes of K. variicola, K. quasipneumoniae and K. pneumoniae. Materials and methods: In silico comparisons and Jaccard analysis of genomic data were used. Fimbrial genes were detected by PCR. Biological assays were performed with plant and clinical isolates. Results: Plant colonization genes such as cellulases, catalases and hemagglutinins were mainly present in K. variicola genomes. Chromosomal β-lactamases were characteristic of this species and had been previously misclassified. K. variicola and K. pneumoniae isolates produced plant hormones. Conclusions: A mosaic distribution of different virulence- and plant-associated genes was found in K. variicola and in K. quasipneumoniae genomes. Some plant colonizing genes were found mainly in K. variicola genomes. The term plantanosis is proposed for plant-borne human infections.

Resumen: Objetivo: Comparar genes de colonización de plantas o de virulencia en los genomas reportados de K. variicola, K. quasipneumoniae y K. pneumoniae. Material y métodos: Se utilizaron análisis in silico y de Jaccard. Por PCR se detectaron genes de fimbrias. Se realizaron ensayos biológicos con aislados de plantas y clínicos. Resultados: Los genes de colonización de plantas como celulasas, catalasas y hemaglutininas se encontraron principalmente en genomas de K. variicola. Las β-lactamasas cromosómicas son características de la especie y en algunos casos estaban mal clasificadas. K. variicola y K. pneumoniae producen hormonas vegetales. Conclusiones: Se encontró una distribución en mosaico de los genes de asociación con plantas y de virulencia en K. variicola y K. quasipneumoniae. Principalmente en K. variicola se encontraron algunos genes involucrados en la colonización de plantas. Se propone el término plantanosis para las infecciones humanas de origen vegetal.

Genome misclassification of Klebsiella variicola and Klebsiella quasipneumoniae isolated from plants, animals and humans / Clasificación errónea de aislados de Klebsiella variicola y Klebsiella quasipneumoniae obtenidos de plantas, animales y humanos

Abstract: Objective: Due to the fact that K. variicola, K. quasipneumoniae and K. pneumoniae are closely related bacterial species, misclassification can occur due to mistakes either in normal biochemical tests or during submission to public databases. The objective of this work was to identify K. variicola and K. quasipneumoniae genomes misclassified in GenBank database. Materials and methods: Both rpoB phylogenies and average nucleotide identity (ANI) were used to identify a significant number of misclassified Klebsiella spp. genomes. Results: Here we report an update of K. variicola and K. Quasipneumoniae genomes correctly classified and a list of isolated genomes obtained from humans, plants, animals and insects, described originally as K. pneumoniae or K. variicola, but known now to be misclassified. Conclusions: This work contributes to recognize the extensive presence of K. variicola and K. quasipneumoniae isolates in diverse sites and samples.

Resumen: Objetivo: Identificar genomas mal clasificados de K. variicola, y K. quasipneumoniae en la base de datos del GenBank. Material y métodos: En el presente estudio se usaron tanto análisis filogenéticos usando rpoB como la identidad media de nucleótidos (ANI, por sus siglas en ingles) para identificar un número significativo de genomas del género Klebsiella. Resultados: Se reportó una actualización de genomas de K. variicola y K. quasipneumoniae correctamente clasificados y una lista de aquellos aislamientos obtenidos de seres humanos, plantas, animales e insectos, descritos originalmente como K. pneumoniae o K. variicola pero ahora se conoce que están mal clasificados. Conclusiones: Este trabajo contribuye a la presencia extensiva de aislamientos de K. variicola y K. quasipneumoniae en diversos sitios y muestras.

Microbial interactions: ecology in a molecular perspective

ABSTRACT The microorganism-microorganism or microorganism-host interactions are the key strategy to colonize and establish in a variety of different environments. These interactions involve all ecological aspects, including physiochemical changes, metabolite exchange, metabolite conversion, signaling, chemotaxis and genetic exchange resulting in genotype selection. In addition, the establishment in the environment depends on the species diversity, since high functional redundancy in the microbial community increases the competitive ability of the community, decreasing the possibility of an invader to establish in this environment. Therefore, these associations are the result of a co-evolution process that leads to the adaptation and specialization, allowing the occupation of different niches, by reducing biotic and abiotic stress or exchanging growth factors and signaling. Microbial interactions occur by the transference of molecular and genetic information, and many mechanisms can be involved in this exchange, such as secondary metabolites, siderophores, quorum sensing system, biofilm formation, and cellular transduction signaling, among others. The ultimate unit of interaction is the gene expression of each organism in response to an environmental (biotic or abiotic) stimulus, which is responsible for the production of molecules involved in these interactions. Therefore, in the present review, we focused on some molecular mechanisms involved in the microbial interaction, not only in microbial-host interaction, which has been exploited by other reviews, but also in the molecular strategy used by different microorganisms in the environment that can modulate the establishment and structuration of the microbial community.

Soil bacteria showing a potential of chlorpyrifos degradation and plant growth enhancement

ABSTRACT Background: Since 1960s, the organophosphate pesticide chlorpyrifos has been widely used for the purpose of pest control. However, given its persistence and toxicity towards life forms, the elimination of chlorpyrifos from contaminated sites has become an urgent issue. For this process bioremediation is the method of choice. Results: Two bacterial strains, JCp4 and FCp1, exhibiting chlorpyrifos-degradation potential were isolated from pesticide contaminated agricultural fields. These isolates were able to degrade 84.4% and 78.6% of the initial concentration of chlorpyrifos (100 mg L-1) within a period of only 10 days. Based on 16S rRNA sequence analysis, these strains were identified as Achromobacter xylosoxidans (JCp4) and Ochrobactrum sp. (FCp1). These strains exhibited the ability to degrade chlorpyrifos in sterilized as well as non-sterilized soils, and were able to degrade 93-100% of the input concentration (200 mg kg-1) within 42 days. The rate of degradation in inoculated soils ranged from 4.40 to 4.76 mg-1 kg-1 d-1 with rate constants varying between 0.047 and 0.069 d-1. These strains also displayed substantial plant growth promoting traits such as phosphate solubilization, indole acetic acid production and ammonia production both in absence as well as in the presence of chlorpyrifos. However, presence of chlorpyrifos (100 and 200 mg L-1) was found to have a negative effect on indole acetic acid production and phosphate solubilization with percentage reduction values ranging between 2.65-10.6% and 4.5-17.6%, respectively. Plant growth experiment demonstrated that chlorpyrifos has a negative effect on plant growth and causes a decrease in parameters such as percentage germination, plant height and biomass. Inoculation of soil with chlorpyrifos-degrading strains was found to enhance plant growth significantly in terms of plant length and weight. Moreover, it was noted that these strains degraded chlorpyrifos at an increased rate (5.69 mg-1 kg-1 d-1) in planted soil. Conclusion The results of this study clearly demonstrate that the chlorpyrifos-degrading strains have the potential to develop into promising candidates for raising the productivity of crops in pesticide contaminated soils.

Rhizobial characterization in revegetated areas after bauxite mining

Abstract Little is known regarding how the increased diversity of nitrogen-fixing bacteria contributes to the productivity and diversity of plants in complex communities. However, some authors have shown that the presence of a diverse group of nodulating bacteria is required for different plant species to coexist. A better understanding of the plant symbiotic organism diversity role in natural ecosystems can be extremely useful to define recovery strategies of environments that were degraded by human activities. This study used ARDRA, BOX-PCR fingerprinting and sequencing of the 16S rDNA gene to assess the diversity of root nodule nitrogen-fixing bacteria in former bauxite mining areas that were replanted in 1981, 1985, 1993, 1998, 2004 and 2006 and in a native forest. Among the 12 isolates for which the 16S rDNA gene was partially sequenced, eight, three and one isolate(s) presented similarity with sequences of the genera Bradyrhizobium, Rhizobium and Mesorhizobium, respectively. The richness, Shannon and evenness indices were the highest in the area that was replanted the earliest (1981) and the lowest in the area that was replanted most recently (2006).

Bioremediation of polyaromatic hydrocarbons (PAHs) using rhizosphere technology

The remediation of polluted sites has become a priority for society because of increase in quality of life standards and the awareness of environmental issues. Over the past few decades there has been avid interest in developing in situ strategies for remediation of environmental contaminants, because of the high economic cost of physicochemical strategies, the biological tools for remediation of these persistent pollutants is the better option. Major foci have been considered on persistent organic chemicals i.e. polyaromatic hydrocarbons (PAHs) due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity. Rhizoremediation, a specific type of phytoremediation that involves both plants and their associated rhizospheric microbes is the creative biotechnological approach that has been explored in this review. Moreover, in this review we showed the significance of rhizoremediation of PAHs from other bioremediation strategies i.e. natural attenuation, bioaugmentation and phytoremediation and also analyze certain environmental factor that may influence the rhizoremediation technique. Numerous bacterial species were reported to degrade variety of PAHs and most of them are isolated from contaminated soil, however few reports are available from non contaminated soil. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Finally, exploring the molecular communication between plants and microbes, and exploiting this communication to achieve better results in the elimination of contaminants, is a fascinating area of research for future perspective.

Componentes alimentarios vegetales y microbianos potencialmente útiles en el tratamiento y control de la giardiasis / Potentially useful in the treatment plant and microbial food components and control of giardiasis

La giardiasis es una infección intestinal de amplia distribución mundial, que presenta manifestaciones clínicas con variaciones desde la infección asintomática, a la enfermedad aguda o crónica asociada con diarrea prolongada y severa y malabsorción de nutrientes. Su agente etiológico es el protozoario Giardia lamblia. La infección se inicia por la ingestión de quistes del parásito, presentes en agua y/o alimentos contaminados o por contacto orofecal directo. Los mecanismos a través de los cuales G. lamblia causa le enfermedad permanecen aún en discusión, pero los principales postulados incluyen tanto alteraciones morfológicas como funcionales de la mucosa intestinal a causa de la adhesión de los trofozoítos a las células epiteliales mediante el disco ventral o suctorio, que afectaría la absorción de nutrientes. El principal tratamiento es la administración de drogas antiparasitarias, muchas de las cuales han demostrado tener un amplio rango de efectos secundarios desagradable, lo cual sumado a la ocurrencia de resultados clínicos insatisfactorios y al surgimiento de cepas resistentes, ha impulsado la búsqueda de nuevas estrategias terapéuticas. Es por ello que el objetivo de esta tesis doctoral fue evaluar la actividad antigiardiásica de componentes alimentarios de origen vegetal y microbiano, como así también la interacción de los mismos con drogas antiparasitarias de uso común.

ABSTRACT: Giardiasis is an intestinal infection of worldwide distribution, presenting with clinical manifestations ranging from asymptomatic infection to acute or chronic disease associated with prolonged and severe diarrhea and malabsorption of nutrients, Its etiologic agent is the protozoan Giardia lamblia. Infection is initiated by ingestion of parasite cysts present in contaminated water and food or by direct fecal-oral contact The mechanisms through which G. lamblia causes disease will remain still under discussion, but the main tenets include both mechanical obstruction as morphological and functional alterations of the intestinal mucosa because of the adherence of trophozoites to epithelial cells by ventral disk that affect nutrient absorption. The main treatment is the administration of antiparasitic drugs, many of which have been shown to have a wide range of unpleasant side effects, which added to the occurrence of unsatisfactory clinical results and the emergence of resistant strains, has prompted the search for new therapeutic strategies.

Antimicrobial Activity of Bacteria Associated with Seaweeds against Plant Pathogens on Par with Bacteria Found in Seawater and Sediments.

Aim: We report antimicrobial activities of bacteria associated with 10 native and one invasive species of seaweeds on par with bacteria found in the seawater and sediment. Bacteria exhibiting antimicrobial activity were phylogenetically analysed using 16S rRNA gene. Place and Duration of Study: Samples of seaweeds, seawater and sediments collected at 6 localities of south east coast of India between December 2009 and January 2010 during monsoon season. Methodology: Culturable bacteria in seaweeds (epibiotics and endobiotics), seawater and sediments were isolated through serial dilutions using 1.5% ZoBell marine agar (HiMedia, India). Bacterial isolates producing antibiotics were identified by screening against commercial antibiotics and they were subjected to morphological, Gram’s staining and biochemical studies. Chemical property and stability of antimicrobial substances obtained from the promising bacteria active against plant pathogens were studied. Phylogenetic analysis of antibiotics-producing marine bacteria was made using 16S rRNA gene sequencing technique. Results: A number of673 isolates obtained through the isolation process were found to be the member of 27 bacterial genera, with species of Bacillus recording a maximum of 40.2%. Generally species of bacterial isolates in the association (seaweeds: epibiotics, 39.54% and endobiotics, 40.74%, seawater 8.61% and sediments 11.11%) produced antibiotics and active against plant pathogens (Xanthomonas axonopodis pv. citri, X. oryzaepv. oryzae and Ustilaginoidea virens) were associated with seaweeds (epibiotics 33.46% and endobiotics 43.11%) and sediments (23.43%). Extracellular components of active bacteria are proteins and retaining bioactivity at pH 7.0, up to 40°C and antifungal property up to 60°C. Extracts obtained from the active bacteria are nonpolar lipophilic substances exhibited only antifungal activity. Conclusion: Bacterial population were considerably higher in seaweeds as compared to seawater and sediments, and at the same time higher bacterial population was recorded in Gulf samples than the open coast samples. Most of the bacterial isolates associated with seaweeds were found to produce antibiotics.

Methylobacterium-plant interaction genes regulated by plant exudate and quorum sensing molecules

Bacteria from the genus Methylobacterium interact symbiotically (endophytically and epiphytically) with different plant species. These interactions can promote plant growth or induce systemic resistance, increasing plant fitness. The plant colonization is guided by molecular communication between bacteria-bacteria and bacteria-plants, where the bacteria recognize specific exuded compounds by other bacteria (e.g. homoserine molecules) and/or by the plant roots (e.g. flavonoids, ethanol and methanol), respectively. In this context, the aim of this study was to evaluate the effect of quorum sensing molecules (N-acyl-homoserine lactones) and plant exudates (including ethanol) in the expression of a series of bacterial genes involved in Methylobacterium-plant interaction. The selected genes are related to bacterial metabolism (mxaF), adaptation to stressful environment (crtI, phoU and sss), to interactions with plant metabolism compounds (acdS) and pathogenicity (patatin and phoU). Under in vitro conditions, our results showed the differential expression of some important genes related to metabolism, stress and pathogenesis, thereby AHL molecules up-regulate all tested genes, except phoU, while plant exudates induce only mxaF gene expression. In the presence of plant exudates there is a lower bacterial density (due the endophytic and epiphytic colonization), which produce less AHL, leading to down regulation of genes when compared to the control. Therefore, bacterial density, more than plant exudate, influences the expression of genes related to plant-bacteria interaction.

Endophytic fungi producing of esterases: evaluation in vitro of the enzymatic activity using pH indicator

A sensitive and efficient colorimetric method was optimized for detection of esterase enzymes produced by endophytic fungi for development of High-Throughput Screening (HTS). The fungi were isolated and obtained previously from plant species of Cerrado and Atlantic Forest located in areas of environmental preservation in the State of Sao Paulo / Brazil, as part of the project "Chemical and biological prospecting endophytic fungi associated to plant species of Cerrado and Atlantic Forest". The compounds ethyl butyrate, ethyl acetate and methyl propionate were used as standards esters which were hydrolyzed by extracellular enzyme from endophytic fungi (EC. 3.1.1.1 -carboxylesterases) for production of carboxylic acids. Thus, the reduction of the pH increases the protonated indicator concentration (bromothymol blue), changing the color of the reaction medium (from blue to yellow), that can be observed and measured by spectrophotometry at 616 nm. The methodology with acid-base indicator was performed on 13 microorganisms, aiming Periconia atropurpurea asapotential source of esterase for biotransformation of short chain esters. The results also evidenced that this methodology showed to be efficient, fast, cheap, having low consumption of reagents and easy development, and can be applied to screen carboxylic-ester hydrolases in a large number of microorganisms.

Métodos para la detección de Agrobacterium a partir de muestras de material vegetal, suelo y agua / Methods for the detection of Agrobacterium from plant, soil and water samples

El género Agrobacterium incluye especies ftopatógenas que inducen la formación de agallas en el cuello o la proliferación de raíces en cabellera en más de 600 especies de dicotiledóneas, y especies no patógenas cuyo hábitat natural es el suelo. Como no es posible erradicar a las especies patógenas y habida cuenta de que más del 80 % de las infecciones puede provenir de viveros, es importante evitar la diseminación de la enfermedad. Por ello, el objetivo de este trabajo ha sido desarrollar técnicas sensibles y precisas que, aisladamente o combinadas, permitan detectar la presencia de especies y biovares de Agrobacterium a partir de muestras de material vegetal, suelo y agua. Se comprobó que con la estrategia combinada de realizar aislamientos en los medios semiselectivos D1, D1-M y YEM-RCT; PCR multiplex sobre el gen 23S ADNr; PCR específca sobre los genes virC1 y virC2 y bioensayos en plántulas de pimiento cv. California Wonder y en hojas cortadas de kalanchoe, se reduce la posibilidad de obtener falsos negativos y/o falsos positivos. Por lo expuesto, esta combinación de técnicas constituye una herramienta adecuada para el diagnóstico de cepas patógenas de Agrobacterium a partir de distintos tipos de muestras.

The genus Agrobacterium includes phytopathogenic bacteria that induce the development of root crown galls and/or aerial galls at the base of the stem or hairy roots on more than 600 species of plants belonging to 90 dicotyledonous families and non-pathogenic species. These bacteria being natural soil inhabitants are particularly diffcult to eradicate, which is a problem in nurseries where more than 80% of infections occur. Since early detection is crucial to avoid the inadvertent spread of the disease, the aim of this work was to develop sensitive and precise identifcation techniques by using a set of semi-selective and differential culture media in combination with a specifc PCR to amplify a partial sequence derived from the virC operon, as well as a multiplex PCR on the basis of 23SrDNA sequences, and biological assays to identify and differentiate species and biovars of Agrobacterium obtained either from soil, water or plant samples. The combination of the different assays allowed us to reduce the number of false positive and negative results from bacteria isolated from any of the three types of samples. Therefore, the combination of multiplex PCR, specifc PCR, isolations in semi-selective D1, D1-M and YEM-RCT media combined with bioassays on cut leaves of Kalanchoe and seedlings of California Wonder pepper cultivar constitute an accurate tool to detect species and biovars of Agrobacterium for diagnostic purposes.

Avaliação microbiológica e parasitológica de alfaces comercializadas no município de São Luís, MA / Evaluation of microbiological and parasitological lettuce commercialized in São Luís, MA

A alface (Lactuca sativa) é a hortaliça folhosa mais comercializada no Brasil. Seu baixo valor calórico a qualifica para diversas dietas, o que favorece o seu consumo sob a forma crua, possibilitando a ocorrência de enfermidades intestinais. O estudo objetivou avaliar a qualidade microbiológica e parasitológica das alfaces comercializadas em supermercados e feiras da cidade de São Luís, MA. Para avaliar a qualidade microbiológica do produto foi utilizada a técnica do NMP (Número Mais Provável) e Pesquisa de Salmonella spp. A análise parasitológica foi realizada pelo método de Hoffman com alterações. As alfaces de todos os estabelecimentos apresentaram índices de coliformes termotolerantes acima do permitido pela legislação e apenas dois estabelecimentos apresentaram pesquisa de Salmonella spp positiva. A presença de cistos de Giárdia lamblia e Entamoeba coli foi detectada penas nas amostras dos supermercados.

Qualidade microbiológica de vegetais minimamente processados / Microbiological quality of processed vegetables

O processamento mínimo de vegetais visa fornecer ao consumidor frutas e hortaliças prontas para o preparo e/ou consumo. As etapas envolvidas neste processamento devem ser realizadas de forma adequada para evitar o desenvolvimento de micro-organismos indesejáveis. Neste contexto, o objetivo deste estudo foi avaliar as condições higiênico-sanitárias de vegetais minimamente processados comercializados na cidade de São José do Rio Preto, SP. Das amostras analisadas, todas apresentaram contagens elevadas para coliformes totais e 20% demonstraram valores superiores ao estabelecido pela legislação para coliformes fecais. A presença de Escherichia coli foi observada em 90% das amostras. Tais resultados indicam a necessidade de adequações de Boas Práticas de Fabricação (BPF) durante o processamento garantindo a segurança dos consumidores.

Calidad microbiológica y bacterias enteropatógenas en vegetales tipo hoja / Microbiological quality and enteropathogenic bacteria in leaf vegetables

Para analizar la calidad microbiológica en vegetales tipo hoja y la incidencia de bacterias enteropatógenas se analizaron 150 muestras (50 lechugas, 50 cilantros y 50 perejiles) recolectadas en dos supermercados de Maracaibo. Se determinó Coliformes Totales (CT) y Escherichia coli (EC) según la norma COVENIN Nº3276:1997; para la determinación de bacterias enteropatógenas (Salmonella, Aeromonas y Vibrio) se utilizaron medios de enriquecimiento y selectivos. La identificación de especies se realizó empleando pruebas bioquímicas. En 81,33% (122/150) de las muestras se obtuvieron contajes de CT entre 10³-10 5 UFC/g. La recuperación de EC fue de 10,00%. La frecuencia de enteropatógenos fue de 28%, siendo Aeromonas el género más aislado con un 95,91%. La mayor recuperación de enteropatógenos se obtuvo en las muestras de cilantro (40,00%), seguida de perejil (34,00%) y lechuga (20,00%); A. caviae fue la especie más recuperada (59,18%) seguida de A. hydrophila (30,62%). Salmonella spp se recuperó en 2 (4,08%) muestras. La presencia de indicadores entéricos (CT y EC) y de bacterias enteropatógenas sugiere que los vegetales tipo hoja presentan una inadecuada calidad sanitaria y pueden ser fuente de gastroenteritis

To analyze the microbiological quality of leaf vegetables and the incidence of enteropathogenic bacteria, 150 samples (50 lettuce, 50 coriander and 50 parsley) collected in two supermarkets in Maracaibo, were studied. Total coliforms (TC) and Escherichia coli (EC) according to COVENIN guideline N° 3276: 1997, were determined; for the identification of enteropathogenic bacteria (Salmonella, Aeromonas, Vibrio), enrichment and selective media were used. Species identification was made using biochemical tests. In 81.33% (122/150) of the samples obtained, TC counts were between 10³-10 5 CFU/g. EC recovery was 10.00%. The frequency of enteropathogens was 28%, with Aeromonas the most isolated genus (95.91%). Greater recovery of enteropathogens was obtained from coriander (40.00%), followed by the parsley (34.00%) and lettuce samples (20.00%); A. caviae was the most recovered specie (59.18%) followed by A. hydrophila (30,62%). Salmonella spp were recovered in 2 samples (4.08%). The presence of enteric indicators (TC and EC) and enteropathogenic bacteria suggests that the sanitary condition of the leafy vegetables is inadequate and can be a source of gastroenteritis

Conservación del ombusillo, planta amenazada de la provincia de Buenos Aires, Argentina / Conserving ombusillo, an endangered plant from the province of Buenos Aires, Argentina

Phytolacca tetramera Hauman "ombusillo", es una especie vegetal endémica del SE de la Provincia de Buenos Aires, Argentina, que se halla en peligro crítico de extinción. Su principal factor de amenaza es la reducción del hábitat por acción antrópica. Esta especie presenta principios activos fungicidas y, posiblemente, dada su afinidad con otras especies del mismo género, presente compuestos antivirales, antitumorales, bactericidas e insecticidas. Se realizaron ensayos de macropropagación con distintas concentraciones de reguladores de crecimiento de tipo auxínicos que muestran claramente un enraizamiento óptimo correspondiente a segmentos de ejes aéreos vegetales “estacas” sometidas a 300 ppm de ácido indol butírico y a segmentos de tallos subterráneos sin aplicación de hormonas. Así mismo, se realizaron ensayos de germinación, en condiciones de luz y de oscuridad, comprobándose que las semillas presentan fotoblastismo positivo con un porcentaje de germinación del 65%, el cual disminuye enormemente luego del año de cosecha.

Phytolacca tetramera Hauman "ombusillo" is an endemic plant species which is in critical danger of becoming extinct; it comes from the south-east of the province of Buenos Aires. The main factor threatening this species is the reduction of its natural environment by antropic action.This species has antifungal properties and, due to its relationship with other species from the same genus, it could also have antiviral, antitumour, antibacterial and insecticidal compounds. Macropropagation experiments were carried out using different concentrations of auxinic growth regulators. Segements of aerial axis “stakes” treated with 300 ppm of indol-butiric acid and segments of underground stems without hormonal treatment provided optimum rooting. Germination experiments in dark and light conditions were also carried out, finding that seeds showed positive photoblastisme with a 65% germination rate which declined considerably after the crop had been harvested.