Validation of a predictive model describing growth of Salmonella in enteral feeds

Silva, Roberta Ribeiro; Moraes, Célia Alencar de; Bessan, Josefina; Vanetti, Maria Cristina Dantas

doi:10.1590/s1517-83822009000100026

Cited by 9 publications

(5 citation statements)

References 17 publications

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“…In a study by Silva and colleagues (2009), S. enterica subsp. enterica sorovar Typhimurium stored at 25 °C for 24hrs increased to population of 5 to 6 log10 at generation time of 34.8 minutes [22]. The study highlighted that at environmental temperature (24 to 29 °C) Salmonella thrives well and therefore explaining the high isolation rates in supermarkets were the vegetables are stored for more than two days.…”

Section: Discussionmentioning

confidence: 99%

A Survey of Potential Bacterial Hazards in Salad Vegetables Sold in Lusaka District, Zambia, in 2018

Pule

Ndashe

Mfune

et al. 2020

Preprint

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Salad vegetables are a source of fresh nutrition and can also serve a vehicle for foodborne pathogens. This was a cross-sectional study conducted in February and March 2018 aimed at isolating some enteropathogens from some salad vegetables. Ten samples of each salad vegetable (carrots, cabbage, cucumbers, and tomatoes) were collected from two supermarkets and two open-markets. A total of 160 samples were collected and analyzed microbiologically for the presence of Shigella spp, Vibrio app, and Salmonella spp. The isolated bacteria were identified by conventional biochemical tests. Vibrio spp were isolated from all the vegetables that were collected from both the two open markets (62.5% and 72.5%) and two supermarkets (67.5% and 77.5%), with the highest isolation rate recorded in cabbages. The frequency of occurrence of Shigella spp and Salmonella spp was higher in supermarkets (50% and 65%; 50% and 15%) than in the open markets (10% and 7.5%; 10% and 35%), respectively. The present study revealed the presence of potential bacterial hazards in salad vegetables sold in both open markets and supermarkets in Lusaka district. The isolated bacterial pathogens are aetiological agents of diarrheal disease that even at low dose could be infectious for sensitive populations.

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Section: Discussionmentioning

confidence: 99%

A Survey of Potential Bacterial Hazards in Salad Vegetables Sold in Lusaka District, Zambia, in 2018

Pule

Ndashe

Mfune

et al. 2020

Preprint

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“…The following references were used to obtain mutation rates: [30,31,32,33,34,35,36,37,38,39] . And the following references were used for generation times: [40,41,42,43,44,45,46,47,48] . Most references give a range of values or multiple values of mutation rates and generation times depending on the culture conditions used.…”

Section: F I G Smentioning

confidence: 99%

de novogene birth as an inevitable consequence of adaptive evolution

Mani

Tlusty

2021

Preprint

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Contrary to long-held views, recent evidence indicates that de novo birth of genes is not only possible but is surprisingly prevalent: a substantial fraction of eukaryotic genomes are composed of orphan genes, which show no homology with any conserved genes. And a remarkably large proportion of orphan genes likely originated denovo from non-genic regions. Here, using a parsimonious mathematical model, we investigate the probability and timescale of de novo gene birth due to spontaneous mutations. We trace how an initially non-genic locus accumulates beneficial mutations to become a gene. We sample across a wide range of biologically feasible distributions of fitness effects (DFE) of mutations, and calculate the conditions conducive to gene birth. We find that in a time frame of millions of years, gene birth is highly likely for a wide range of DFEs. Moreover, when we allow DFEs to fluctuate, which is expected given the long time frame, gene birth in the model becomes practically inevitable. This supports the idea that gene birth is a ubiquitous process, and should occur in a wide variety of organisms. Our results also demonstrate that intergenic regions are not inactive and silent but are more like dynamic storehouses of potential genes.

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“…The following references were used to obtain mutation rates: [31,32,33,34,35,36,37,38,39,40]. And the following references were used for generation times: [41,42,43,44,45,46,47,48,49]. Most references give a range of values or multiple values of mutation rates and generation times depending on the culture conditions used.…”

Section: Supplementary Informationmentioning

confidence: 99%

de novo gene birth as an inevitable consequence of adaptive evolution

Mani¹,

Tlusty²

2021

Preprint

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Phylostratigraphy suggests that new genes are continually born de novo from non-genic sequences. The genes that persist found new lineages, contributing to the adaptive evolution of organisms. While recent evidence supports the view that de novo gene birth is frequent and widespread, the mechanisms underlying this process are yet to be discovered. Here we hypothesize and examine a potential general mechanism of gene birth driven by the accumulation of beneficial mutations at non-genic loci. To demonstrate this possibility, we model this mechanism, within the boundaries set by current knowledge on mutation effects. Estimates from this simple analysis are in line with observations of recurrent and extensive gene birth in genomics studies. Thus, we propose that rather than being inactive and silent, non-genic regions are likely to be dynamic storehouses of potential genes. Furthermore, two simple studies, taken together, lend support to such a mechanism of gene birth: first, random sequences can gain functionality, provided they are consistently expressed [10]. And second, it was demonstrated that new promoters could easily evolve in E. coli [11]. These studies highlight the possibility that non-genic sequences can, in stages, gain the hallmarks of genes: regulated expression and functionality.Here we hypothesize that gene birth can be understood as an inevitable consequence of adaptive evolution of non-genic sequences. To demonstrate this, we present a blueprint for a minimal model of gene birth that uses characteristics of spontaneous mutations, the simplest units of adaptive evolution, as its building blocks. Specifically, we consider the

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Validation of a predictive model describing growth of Salmonella in enteral feeds

Cited by 9 publications

References 17 publications

A Survey of Potential Bacterial Hazards in Salad Vegetables Sold in Lusaka District, Zambia, in 2018

A Survey of Potential Bacterial Hazards in Salad Vegetables Sold in Lusaka District, Zambia, in 2018

de novogene birth as an inevitable consequence of adaptive evolution

de novo gene birth as an inevitable consequence of adaptive evolution

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