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2.
J Chem Ecol ; 46(8): 699-706, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32533351

RESUMO

It is known that plant and associated bacteria coevolved, but just now the roles of chemical signaling compounds in these intricate relationships have been systematically studied. Many Gram-negative bacteria produce N-acyl-L-homoserine lactones (AHL), chemical signals used in quorum-sensing bacterial communications mechanisms. In recent years, it has been shown that these compounds may also influence the development of plants, acting as allelochemicals, in still not well understood eukaryot-prokaryot interactions. In the present work, a quorum-sensing molecule produced by the tomato associated bacterium Pseudomonas sp. was characterized and its effects on germination and growth of tomato seedlings were accessed. The chemical study of the bacterium extract led to the identification of N-3-oxo-dodecanoyl-L-homoserine lactone (1), using gas chromatography coupled to electron impact mass spectrometry (GC-MS), and ultra-high resolution Qq-time-of-flight mass spectrometry (UHR-QqTOF-MS) equipped with an electrospray ionization source (ESI). The synthetic compound was tested at different concentrations in tomato to evaluate its effects on seed germination and seedlings root growth. Inhibition of tomato seed germination and root growth were observed in the presence of micromolar concentrations of the compound 1. Scanning electron microscopy evidenced morphological alterations on roots in the presence of the compound, with reduction of growth, impaired root hairs development and cracks in the rhizodermis.

3.
PLoS One ; 15(1): e0227422, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31923250

RESUMO

Studies of the interactions between plants and their microbiome have been conducted worldwide in the search for growth-promoting representative strains for use as biological inputs for agriculture, aiming to achieve more sustainable agriculture practices. With a focus on the isolation of plant growth-promoting (PGP) bacteria with ability to alleviate N stress, representative strains that were found at population densities greater than 104 cells g-1 and that could grow in N-free semisolid media were isolated from soils under different management conditions and from the roots of tomato (Solanum lycopersicum) and lulo (Solanum quitoense) plants that were grown in those soils. A total of 101 bacterial strains were obtained, after which they were phylogenetically categorized and characterized for their basic PGP mechanisms. All strains belonged to the Proteobacteria phylum in the classes Alphaproteobacteria (61% of isolates), Betaproteobacteria (19% of isolates) and Gammaproteobacteria (20% of isolates), with distribution encompassing nine genera, with the predominant genus being Rhizobium (58.4% of isolates). Strains isolated from conventional horticulture (CH) soil composed three bacterial genera, suggesting a lower diversity for the diazotrophs/N scavenger bacterial community than that observed for soils under organic management (ORG) or secondary forest coverture (SF). Conversely, diazotrophs/N scavenger strains from tomato plants grown in CH soil comprised a higher number of bacterial genera than did strains isolated from tomato plants grown in ORG or SF soils. Furthermore, strains isolated from tomato were phylogenetically more diverse than those from lulo. BOX-PCR fingerprinting of all strains revealed a high genetic diversity for several clonal representatives (four Rhizobium species and one Pseudomonas species). Considering the potential PGP mechanisms, 49 strains (48.5% of the total) produced IAA (2.96-193.97 µg IAA mg protein-1), 72 strains (71.3%) solubilized FePO4 (0.40-56.00 mg l-1), 44 strains (43.5%) solubilized AlPO4 (0.62-17.05 mg l-1), and 44 strains produced siderophores (1.06-3.23). Further, 91 isolates (90.1% of total) showed at least one PGP trait, and 68 isolates (67.3%) showed multiple PGP traits. Greenhouse trials using the bacterial collection to inoculate tomato or lulo plants revealed increases in plant biomass (roots, shoots or both plant tissues) elicited by 65 strains (54.5% of the bacterial collection), of which 36 were obtained from the tomato rhizosphere, 15 were obtained from the lulo rhizosphere, and 14 originated from samples of soil that lacked plants. In addition, 18 strains showed positive inoculation effects on both Solanum species, of which 12 were classified as Rhizobium spp. by partial 16S rRNA gene sequencing. Overall, the strategy adopted allowed us to identify the variability in the composition of culturable diazotroph/N-scavenger representatives from soils under different management conditions by using two Solanum species as trap plants. The present results suggest the ability of tomato and lulo plants to enrich their belowground microbiomes with rhizobia representatives and the potential of selected rhizobial strains to promote the growth of Solanum crops under limiting N supply.


Assuntos
Bactérias/isolamento & purificação , Fixação de Nitrogênio/fisiologia , Rizosfera , Microbiologia do Solo , Solanum/microbiologia , Fenômenos Fisiológicos Bacterianos , Biodiversidade , Produtos Agrícolas/crescimento & desenvolvimento , Lycopersicon esculentum/microbiologia , Microbiota , Nitrogênio/metabolismo , Desenvolvimento Vegetal , Proteobactérias/isolamento & purificação , Solanum/genética , Especificidade da Espécie
5.
J. bras. nefrol ; 39(4): 462-466, Oct.-Dec. 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-893787

RESUMO

Abstract Primary hyperoxaluria (PH) is a very rare genetic disorder; it is characterized by total or partial deficiency of the enzymes related to the metabolism of glyoxylate, with an overproduction of calcium oxalate that is deposited in different organs, mainly the kidney, leading to recurrent lithiasis, nephrocalcinosis and end stage renal disease (ESRD). In patients with ESRD that receive kidney transplantation alone, the disease has a relapse of 100%, with graft loss in a high percentage of patients in the first 5 years of transplantation. Three molecular disorders have been described in PH: mutation of the gene alanin glioxalate aminotransferase (AGXT); glyoxalate reductase/hydroxy pyruvate reductase (GRHPR) and 4-OH-2-oxoglutarate aldolase (HOGA1). We present two cases of patients with a history of renal lithiasis who were diagnosed with primary hyperoxaluria in the post-transplant period, manifested by early graft failure, with evidence of calcium oxalate crystals in renal biopsy, hyperoxaluria, hyperoxalemia, and genetic test compatible; they were managed with proper diet, abundant oral liquids, pyridoxine, hydrochlorothiazide and potassium citrate; however, they had slow but progressive deterioration of their grafts function until they reached end-stage chronic renal disease.


Resumo A hiperoxalúria primária (HP) é um distúrbio genético muito raro, caracterizado por deficiência total ou parcial das enzimas relacionadas ao metabolismo do glioxilato, superprodução de oxalato de cálcio que se deposita em vários órgãos (principalmente os rins) resultando em litíase recorrente, nefrocalcinose e doença renal terminal (DRT). Nos pacientes com DRT que recebem transplante renal, a doença apresenta recidiva em 100% dos casos, com perda do enxerto nos primeiros cinco anos após o transplante num elevado percentual de pacientes. Três distúrbios moleculares foram descritos na HP: mutação dos genes da alanina-glioxilato aminotransferase (AGXT), glioxilato redutase/hidroxipiruvato redutase (GRHPR) e 4-OH-2-oxoglutarato aldolase (HOGA1). Apresentamos dois casos de pacientes com histórico de litíase renal diagnosticados com hiperoxalúria primária no período pós-transplante, manifestada na forma de perda precoce do enxerto com evidências de cristais de oxalato de cálcio na biópsia renal, hiperoxalúria, hiperoxalemia e testes genéticos compatíveis. Os pacientes foram tratados com abordagem nutricional, líquidos orais em abundância, piridoxina, hidroclorotiazida e citrato de potássio. Contudo, os pacientes apresentaram deterioração lenta e gradual da função do enxerto e evoluíram para doença renal terminal.


Assuntos
Humanos , Feminino , Adulto , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico , Hiperoxalúria Primária/diagnóstico , Transplante de Rim
6.
Front Microbiol ; 8: 1873, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29018432

RESUMO

Although Azospirillum strains used in commercial inoculant formulations presents diazotrophic activity, it has been reported that their ability to produce phytohormones plays a pivotal role in plant growth-promotion, leading to a general recommendation of its use in association with regular N-fertilizer doses. In addition, a high variability in the effectiveness of Azospirillum inoculants is still reported under field conditions, contributing to the adoption of the inoculation technology as an additional management practice rather than its use as an alternative practice to the use of chemical inputs in agriculture. To investigate whether the content of stress-resistance biopolymers would improve the viability and performance of Azospirillum inoculants when used as substitute of N-fertilizers, biomass of A. brasilense strain Ab-V5 enriched in exopolysaccharides (EPS) and polyhydroxybutirate (PHB) was produced using a new culture medium developed by factorial mixture design, and the effectiveness of resulting inoculants was evaluated under field conditions. The culture medium formulation extended the log phase of A. brasilense cultures, which presented higher cell counts and increased EPS and PHB contents than observed in the cultures grown in the OAB medium used as control. An inoculation trial with maize conducted under greenhouse conditions and using the biopolymers-enriched Ab-V5 cells demonstrated the importance of EPS and PHB to the long term bacterial viability in soil and to the effectiveness of inoculation. The effectiveness of liquid and peat inoculants prepared with Ab-V5 cells enriched with EPS and PHB was also evaluated under field conditions, using maize as target crop along different seasons, with the inoculants applied directly over seeds or at topdressing under limiting levels of N-fertilization. No additive effect on yield resulted from inoculation under high N fertilizer input, while inoculated plants grown under 80% reduction in N fertilizer showed yields at levels compared to fully fertilized plants, regardless the inoculation method. The presented data highlights the feasibility to partially substitute the N-fertilizer demand in non-legume crops using high-quality inoculant formulations, prepared with diazotrophic bacteria enriched with stress-resistance biopolymers that confer increased viability an effectiveness to the bacterial cells.

7.
J Bras Nefrol ; 39(4): 462-466, 2017.
Artigo em Inglês, Português | MEDLINE | ID: mdl-29319775

RESUMO

Primary hyperoxaluria (PH) is a very rare genetic disorder; it is characterized by total or partial deficiency of the enzymes related to the metabolism of glyoxylate, with an overproduction of calcium oxalate that is deposited in different organs, mainly the kidney, leading to recurrent lithiasis, nephrocalcinosis and end stage renal disease (ESRD). In patients with ESRD that receive kidney transplantation alone, the disease has a relapse of 100%, with graft loss in a high percentage of patients in the first 5 years of transplantation. Three molecular disorders have been described in PH: mutation of the gene alanin glioxalate aminotransferase (AGXT); glyoxalate reductase/hydroxy pyruvate reductase (GRHPR) and 4-OH-2-oxoglutarate aldolase (HOGA1). We present two cases of patients with a history of renal lithiasis who were diagnosed with primary hyperoxaluria in the post-transplant period, manifested by early graft failure, with evidence of calcium oxalate crystals in renal biopsy, hyperoxaluria, hyperoxalemia, and genetic test compatible; they were managed with proper diet, abundant oral liquids, pyridoxine, hydrochlorothiazide and potassium citrate; however, they had slow but progressive deterioration of their grafts function until they reached end-stage chronic renal disease.


Assuntos
Hiperoxalúria Primária/diagnóstico , Transplante de Rim , Complicações Pós-Operatórias/diagnóstico , Adulto , Feminino , Humanos , Pessoa de Meia-Idade
8.
Biomedica ; 36(4): 498-503, 2016 Dec 01.
Artigo em Espanhol | MEDLINE | ID: mdl-27992975

RESUMO

Light chain-associated kidney compromise is frequent in patients with monoclonal gammopathies; it affects the glomeruli or the tubules, and its most common cause is multiple myeloma. It may develop after a kidney transplant due to recurrence of a preexisting multiple myeloma or it can be a de novo disease manifesting as graft dysfunction and proteinuria. A kidney biopsy is always necessary to confirm the diagnosis.We describe three cases of kidney graft dysfunction due to multiple myeloma in patients without presence of the disease before the transplant.


Assuntos
Transplante de Rim/efeitos adversos , Mieloma Múltiplo/etiologia , Disfunção Primária do Enxerto/etiologia , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biópsia , Transplante de Medula Óssea , Terapia Combinada , Evolução Fatal , Humanos , Cadeias Leves de Imunoglobulina/análise , Imunossupressores/efeitos adversos , Falência Renal Crônica/cirurgia , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/diagnóstico , Mieloma Múltiplo/terapia , Proteínas do Mieloma/análise , Proteinúria/etiologia
9.
Acta méd. colomb ; 41(4): 266-268, oct.-dic. 2016. tab
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-949525

RESUMO

Resumen La toxoplasmosis posterior al trasplante renal es una condición infrecuente, pero asociada con alta morbilidad y mortalidad. Generalmente ocurre en los primeros tres meses cuando la inmunosupresión es mayor, siendo más común la presentación con encefalitis y neumonitis. El compromiso del tracto gastrointestinal es inusual y con síntomas inespecíficos. Su diagnóstico es un reto pues no siempre existe seroconversión en estadios tempranos de la infección o no hay evidencia histológica del parásito; es aquí donde la biología molecular y la historia clínica pueden resultar útiles para el diagnóstico oportuno que favorezca un buen desenlace. Describimos el caso de un paciente con síntomas generales, náuseas y emesis en el periodo postrasplante renal temprano atribuidos primero a reactivación de citomegalovirus con diagnóstico posterior de gastritis por Toxoplasma gondii. Recibió tratamiento con trimetoprim sulfametoxazol por seis semanas con resolución completa de los síntomas. (Acta Med Colomb 2016; 40: 266-268).


Abstract Toxoplasmosis following renal transplantation is an uncommon condition, but is associated with high morbidity and mortality. It usually occurs in the first three months when immunosuppression is greater, being more common the presentation with encephalitis and pneumonitis. The involvement of the gastrointestinal tract is unusual and with nonspecific symptoms. Its diagnosis is a challenge because there is not always seroconversion in the early stages of infection or there is no histological evidence of the parasite; it is here that molecular biology and clinical history can be useful for a timely diagnosis that may favor a good outcome. The case of a patient with general symptoms, nausea and emesis in the early renal transplant period attributed initially to reactivation of cytomegalovirus with subsequent diagnosis of gastritis by Toxoplasma gondii, is described. He received treatment with trimethoprim sulfamethoxazole for six weeks with complete resolution of symptoms. (Acta Med Colomb 2016; 40: 266-268).

10.
Biomédica (Bogotá) ; 36(4): 498-503, dic. 2016. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-950914

RESUMO

RESUMEN La enfermedad renal asociada a cadenas ligeras es frecuente en el contexto de las gammapatías monoclonales, afecta los glomérulos o los túbulos renales, y su causa más común es el mieloma múltiple. Puede desarrollarse después de un trasplante renal por recurrencia de un mieloma múltiple ya existente, o puede ser de diagnóstico nuevo y presentarse con deterioro de la función renal y proteinuria. Siempre se requiere una biopsia renal para confirmar el diagnóstico.


ABSTRACT Light chain-associated kidney compromise is frequent in patients with monoclonal gammopathies; it affects the glomeruli or the tubules, and its most common cause is multiple myeloma. It may develop after a kidney transplant due to recurrence of a preexisting multiple myeloma or it can be a de novo disease manifesting as graft dysfunction and proteinuria. A kidney biopsy is always necessary to confirm the diagnosis.

11.
Acta méd. colomb ; 41(1): 58-61, Jan.-Mar, 2016. ilus, tab
Artigo em Espanhol | LILACS-Express | LILACS | ID: lil-797379

RESUMO

El síndrome de hiperestimulación ovárica es una complicación frecuente que se puede presentar en pacientes que reciben tratamientos de inducción de la ovulación y como consecuencia pueden desarrollar un síndrome edematoso grave con falla de uno o varios órganos; presentamos el caso de una paciente con falla renal aguda asociada a síndrome de hiperestimulación ovárica. (Acta Med Colomb 2016; 41:58-61).


Ovarian hyperstimulation syndrome is a common complication that can occur in patients receiving treatment for ovulation induction and as a consequence may develop a severe edematous syndrome with failure of one or more organs; the case of a patient with acute renal failure associated with ovarian hyperstimulation syndrome is presented. (Acta Med Colomb 2016; 41:58-61).

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