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1.
J Dairy Res ; : 1-4, 2022 Feb 11.
Article in English | MEDLINE | ID: mdl-35144712

ABSTRACT

In this research communication the genetic diversity of Pseudomonas fluorescens (n = 67) and Pseudomonas putida (n = 44) isolated from refrigerated raw milk from bulk tank trucks were verified. The relationship between the genetic profile of the isolates and their lipoproteolytic potential was evaluated using skim milk agar and tributyrin agar (21°C/72 h). The lipoproteolytic potential (low or high), evaluated by the diameter of the halos (cm), was correlated with the number of milk producing properties that contributed to each sample (one sample = one bulk tank truck; 8-80 producers/sample) and the distance between the dairy properties and the processing plant (21-370 km). P. fluorescens was confirmed in all samples, while P. putida in 60% samples. For both species, two clusters (I and II) were observed, and the first one showed lower genotypic diversity and the presence of isolates with 100% similarity. P. fluorescens isolates presenting at least 70% similarity were 83.9% in Cluster I (n = 31) and 44.4% in Cluster II. In both clusters (I and II) observed in the P. fluorescens dendrogram, the occurrence of high proteolytic and lipolytic potential were equivalent. The higher the number of farms per milk sample, the greater the lipoproteolytic intensity of P. fluorescens isolates. In relation to P. putida isolates, 74% presented at least 50% similarity in Cluster I (n = 27) and only 35% in Cluster II (n = 17). The occurrence of high proteolysis linked to P. putida was proportional between both Clusters, but the occurrence of high lipolysis was greater in Cluster II. No significant association was detected between P. putida isolates and the variables studied. The results indicate the circulation of P. putida and P. fluorescens with 100% similarity in different milk producing regions. The level of genetic diversity was related only to the lipolytic capacity of P. putida.

2.
Semina ciênc. agrar ; 41(4): 1421-1426, jul.-ago. 2020. tab
Article in English | VETINDEX | ID: biblio-1373679

ABSTRACT

This study aimed to determine the frequency of Pseudomonas fluorescens, P. putida, and P. aeruginosa in refrigerated raw milk; their proteolytic potential; and your association with the aprX gene. Of the 173 isolates confirmed as belonging to Pseudomonas spp., 37% were P. fluorescens, 25.4% P. putida, and none belongs to P. aeruginosa. The aprX gene was distributed proportionally between P. putida (68%) and P. fluorescens (75%), but it was not associated with low or high proteolytic potential in both species. P. putida (16) and P. fluorescens (14) isolates with no aprX gene identified also had proteolytic potential. Considering the synthesis of proteases other than AprX by the isolates under study, we concluded that P. fluorescens and P. putida represented 62.4% of the Pseudomonas genus, with high probability of having the aprX gene and proteolytic potential. However, there was no association between the deteriorating potential with the presence of the aprX gene.(AU)


O objetivo do estudo foi verificar a frequência, em leite cru refrigerado de Pseudomonas fluorescens, P. putida e P. aeruginosa, o potencial proteolítico dos isolados e sua associação com a presença do gene aprX. Dos 173 isolados confirmados como pertencente ao gênero Pseudomonas spp, 37% foram P. fluorescens, 25,4% P. putida e nenhum pertencia à espécie P. aeruginosa. A prevalência do gene aprX se distribuiu proporcionalmente entre P.putida (68%) e P.fluorescens (75%) porém não foi associada ao baixo ou alto potencial proteolítico nas duas espécies avaliadas. P. putida (16) e P. fluorescens (14) que não tiveram o gene aprX identificado também expressaram potencial proteolítico, considerando-se a síntese de outras proteases além da AprX pelos isolados estudados. Concluiu-se que Pseudomonas fluorescens e P. putida representaram 62,4 % do gênero Pseudomonas ssp., com alta probabilidade da presença do gene aprX e potencial proteolítico, porém sem associação da expressão do potencial deteriorante com a presença do gene aprX.(AU)


Subject(s)
Animals , Female , Peptide Hydrolases/analysis , Pseudomonas/isolation & purification , Milk/microbiology , Ascorbate Peroxidases/genetics
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