RESUMO
On the basis of our previous results on potential immunoregulation of Lactobacillus acidophilus NCFM, the immunoregulatory effects of exopolysaccharides (EPS) isolated from L. acidophilus NCFM and their regulating mechanisms are further investigated in the current research. Stimulated by EPS preparations, four immune-related genes in the human colorectal adenocarcinoma cell line Caco-2 cells, namely, interleukin-1α (IL-1α), chemokine C-C motif 2 (CCL2), tumor necrosis factor α (TNF-α), and pentraxin 3 (PTX3), first showed an increase at 2-4 h, peaked at 4 h, and then decreased at 4-12 h. Similar trends were observed in vivo: four genes showed transient expression (highest on the 4th day) in the cecum and colon of mice. Meanwhile, the organ coefficient, clearance index and phagocytic index all significantly increased with time extension and dose increase of EPS stimulation. EPS triggered NF-κB and p38 mitogen-activated protein kinase (p38 MAPK) signaling pathways in Caco-2 cells, and the activated pathways initiated the genes expression. EPS compounds from L. acidophilus NCFM may play an important role in host immunoregulation and might be applied as a new type of immunoregulatory agent in functional foods.
Assuntos
Fatores Imunológicos/farmacologia , Lactobacillus acidophilus/química , Polissacarídeos Bacterianos/farmacologia , Animais , Proteína C-Reativa/genética , Proteína C-Reativa/imunologia , Células CACO-2 , Quimiocina CCL2/genética , Quimiocina CCL2/imunologia , Expressão Gênica/efeitos dos fármacos , Humanos , Fatores Imunológicos/administração & dosagem , Fatores Imunológicos/isolamento & purificação , Interleucina-1alfa/genética , Interleucina-1alfa/imunologia , Camundongos , Camundongos Endogâmicos BALB C , NF-kappa B/genética , NF-kappa B/imunologia , Polissacarídeos Bacterianos/administração & dosagem , Componente Amiloide P Sérico/genética , Componente Amiloide P Sérico/imunologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologiaRESUMO
An orange-coloured bacterium, CCBAU 05354(T), was isolated from the soybean rhizosphere following growth on NA medium. The sample was taken from a field in Hebei province, People's Republic of China. The cells were aerobic, Gram-stain-negative, short rods (0.4-0.6 x 0.7-1.7 microm) and non-motile. Growth occurred at 28 degrees C (not at 10 or 37 degrees C), pH 6.0-10.0, and in the presence of 0-1 % NaCl (w/v). Flexirubin pigment was produced and the cells were resistant to some antibiotics. A phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CCBAU 05354(T) was closely related to Niabella soli KACC 12604(T) (95.1 % sequence similarity). The predominant cellular fatty acids were iso-C(15 : 0), iso-C(15 : 1) G, iso-C(17 : 0) 3-OH and summed feature 3 (comprising C(16 : 1)omega7c and/or C(16 : 1)omega6c). The DNA G+C content was 42 mol%. On the basis of the phylogenetic, phenotypic and chemotaxonomic data, strain CCBAU 05354(T) represents a novel species of the genus Niabella, for which the name Niabella yanshanensis sp. nov. is proposed. The type strain is CCBAU 05354(T) (=LMG 24661(T) =HAMBI 3031(T)).
Assuntos
Bacteroidetes/isolamento & purificação , Glycine max/microbiologia , Microbiologia do Solo , Bacteroidetes/classificação , Bacteroidetes/genética , Bacteroidetes/metabolismo , DNA Bacteriano/genética , DNA Ribossômico/genética , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Dados de Sequência Molecular , Filogenia , Raízes de Plantas/microbiologia , RNA Ribossômico 16S/genéticaRESUMO
A total of 128 bacterial test strains originated from Astragalus, Caragana, Gueldenstaedtia, Medicago, Melilotus, Oxytropis, Trifolium, and Vicia grown in Tibet were characterized phenotypically and genomically. Based upon the consensus of grouping results, they were identified as 16 putative species. Twenty-five test strains belonging to seven putative species of Agrobacterium, Bradyrhizobium, and Rhizobium might be nonsymbiotic bacteria and the remaining 103 test strains were symbiotic bacteria belonging to Mesorhizobium, Rhizobium, and Sinorhizobium meliloti. Although no novel taxon was detected in the symbiotic bacteria, several characters including the alkaliphilic psychrotolerance revealed that the Tibetan rhizobia could be ecotypes adapted to the local conditions. The results also demonstrated that frequent lateral transfer of symbiotic genes might have happened in the Tibetan rhizobia since nodC genes similar to that of S. meliloti were found in several Rhizobium test strains and all the Mesorhizobium species had very similar nodC genes despite their genomic background. All of these findings demonstrated that the Tibetan rhizobia were an important resource for further studies on rhizobial ecology and application.
Assuntos
Alphaproteobacteria/classificação , Alphaproteobacteria/isolamento & purificação , Fabaceae/microbiologia , Raízes de Plantas/microbiologia , Aciltransferases/genética , Alphaproteobacteria/genética , Alphaproteobacteria/metabolismo , Proteínas de Bactérias/genética , DNA Bacteriano/análise , DNA Ribossômico/análise , DNA Espaçador Ribossômico/análise , Fabaceae/classificação , N-Acetilglucosaminiltransferases/genética , Fixação de Nitrogênio , Filogenia , Reação em Cadeia da Polimerase/métodos , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética , Mapeamento por Restrição , Rhizobiaceae/classificação , Rhizobiaceae/genética , Rhizobiaceae/isolamento & purificação , Rhizobiaceae/metabolismo , Simbiose/genética , TibetRESUMO
Fourteen strains representing 11 Caragana-nodulating Mesorhizobium genomic species were identified as representing Mesorhizobium amorphae, Mesorhizobium huakuii, Mesorhizobium septentrionale and groups related to Mesorhizobium plurifarium, Mesorhizobium temperatum, Mesorhizobium tianshanense and Mesorhizobium mediterraneum by sequencing of the 16S rRNA gene, 16S-23S internal transcribed spacer, partial housekeeping recA gene, and previously performed sodium dodecyl sulfate polyacrylamide gel electrophoresis of proteins and BOX-PCR fingerprinting. Despite their different taxonomic affiliation, highly similar symbiotic genes (>93% similarity for nodC and >91.8% similarity for nifH) were found among the Caragana strains and the three type strains for M. tianshanense, M. temperatum and M. septentrionale. Cross nodulation tests revealed that each of these 14 Caragana mesorhizobia and the three type strains mentioned above could effectively infect each of their original host plants, Caragana microphylla, Glycyrrhiza (host for M. tianshanense type strain) and Astragalus adsurgens (host for M. temperatum and M. septentrionale type strains). These results provide evidence that different Mesorhizobium species can nodulate with Caragana, and they have similar symbiotic genes (probably acquired by a phenomenon of lateral gene transfer) and common host ranges.
Assuntos
Alphaproteobacteria/classificação , Alphaproteobacteria/genética , Caragana/microbiologia , Genes Bacterianos , Simbiose , Alphaproteobacteria/isolamento & purificação , Alphaproteobacteria/fisiologia , Proteínas de Bactérias/genética , Impressões Digitais de DNA , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/genética , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , N-Acetilglucosaminiltransferases/genética , Oxirredutases/genética , Proteoma/análise , RNA Ribossômico 16S/genética , Recombinases Rec A/genética , Análise de Sequência de DNA , Homologia de Sequência de AminoácidosRESUMO
A total of 63 bacterial strains were isolated from root nodules of Kummerowia striata and K. stipulacea grown in different geographic regions of China. These bacteria could be divided into fast-growing (FG) rhizobia and slow-growing (SG) rhizobia according to their growth rate. Genetic diversity and taxonomic relationships among these rhizobia were revealed by PCR-based 16 S rDNA RFLP and sequencing, 16 S-IGS RFLP, SDS-PAGE of whole cell soluble proteins, BOX-PCR and symbiotic gene (nifH/nodC) analyses. The symbiotic FG strains were mainly isolated from temperate regions and they were identified as four genomic species in Rhizobium and Sinorhizobium meliloti based on the consensus of grouping results. The SG strains were classified as five genomic species within Bradyrhizobium and they were mainly isolated fron the subtropic and tropical regions. The phylogenetic analyses of nifH and nodC genes showed relationships similar to that of 16 S rDNA but the symbiotic genes of Bradyrhizobium strains isolated from Kummerowia were distinct from those isolated from Arachis and soybean. These results offered evidence for rhizobial biogeography and demonstrated that the Kummerowia-nodulating ability might have evolved independently in different regions in association with distinctive genomic species of rhizobia.