ABSTRACT
Brucellosis is a zoonosis caused by Brucella, which poses a great threat to human health and animal husbandry. Pathogen surveillance is an important measure to prevent brucellosis, but the traditional method is time-consuming and not suitable for field applications. In this study, a recombinase polymerase amplification-SYBR Green I (RPAS) assay was developed for the rapid and visualized detection of Brucella in the field by targeting BCSP31 gene, a conserved marker. The method was highly specific without any cross-reactivity with other common bacteria and its detection limit was 2.14 × 104 CFU/mL or g of Brucella at 40 °C for 20 min. It obviates the need for costly instrumentation and exhibits robustness towards background interference in serum, meat, and milk samples. In summary, the RPAS assay is a rapid, visually intuitive, and user-friendly detection that is highly suitable for use in resource-limited settings. Its simplicity and ease of use enable swift on-site detection of Brucella, thereby facilitating timely implementation of preventive measures.
ABSTRACT
During a study of the diversity and phylogeny of rhizobia in the root nodules of Kummerowia striata grown in north-western China, four strains were classified in the genus Rhizobium on the basis of their 16S rRNA gene sequences. The 16S rRNA gene sequences of three of these strains were identical and that of the other strain, which was the only one isolated in Yangling, differed from the others by just 1 bp. The16S rRNA gene sequences of the four strains showed a mean similarity of 99.3â% with the most closely related, recognized species, Rhizobium vitis. The corresponding recA and glnA gene sequences showed similarities with established species of Rhizobium of less than 86.5â% and less than 89.6â%, respectively. These low similarities indicated that the four strains represented a novel species of the genus Rhizobium. The strains were also found to be distinguishable from the closest related, established species (R. vitis) by rep-PCR DNA fingerprinting, analysis of cellular fatty acid profiles and from the results of a series of phenotypic tests. The level of DNA-DNA relatedness between the representative strain CCNWSX 0483(T) and Rhizobium vitis IAM 14140(T) was only 40.13â%. Therefore, a novel species, Rhizobium taibaishanense sp. nov., is proposed, with strain CCNWSX 0483(T) (â=âACCC 14971(T)â=âHAMBI 3214(T)) as the type strain. In nodulation and pathogenicity tests, none of the four strains of Rhizobium taibaishanense sp. nov. was able to induce any nodule or tumour formation on plants. As no amplicons were detected when DNA from the strains was run in PCR with primers for the detection of nodA, nifH and virC gene sequences, the strains probably do not carry sym or vir genes.
Subject(s)
Fabaceae/microbiology , Plant Roots/microbiology , Rhizobium/classification , Rhizobium/isolation & purification , Bacterial Typing Techniques , Base Composition , China , DNA, Bacterial/analysis , Fatty Acids/analysis , Glutamate-Ammonia Ligase/genetics , Molecular Sequence Data , Nucleic Acid Hybridization , Phenotype , Phylogeny , Polymerase Chain Reaction , RNA, Ribosomal, 16S/genetics , Rec A Recombinases/genetics , Rhizobium/genetics , Rhizobium/metabolism , Sequence Analysis, DNA , Species SpecificityABSTRACT
In the title compound, C(12)H(15)ClO(3), the eth-oxy group is nearly coplanar with the benzene ring, making a dihedral angle of 9.03â (4)°, and is involved in an intra-molecular O-Hâ¯O hydrogen bond to the neighbouring hy-droxy group.
