scholarly journals Assessing the role of bacterial plasmid replication in a competition model of sensitive and resistant bacteria to antibiotics

2021 ◽  
Vol 6 (9) ◽  
pp. 9446-9467
Author(s):  
Eduardo Ibargüen-Mondragón ◽  
◽  
Miller Cerón Gómez ◽  
Edith M. Burbano-Rosero ◽  
Keyword(s):  
Competition Model ◽  
Resistant Bacteria ◽  
Plasmid Replication ◽  
Bacterial Plasmid

scholarly journals A Gnotobiotic Model to Examine Plant and Microbiome Contributions to Survival under Arsenic Stress

2020 ◽  
Vol 9 (1) ◽  
pp. 45
Author(s):  
María del Carmen Molina ◽  
James F. White ◽  
Sara García-Salgado ◽  
M. Ángeles Quijano ◽  
Natalia González-Benítez
Keyword(s):  
Seedling Growth ◽  
Endophytic Bacteria ◽  
Root Hairs ◽  
Resistant Bacteria ◽  
Relative Importance ◽  
Early Stages ◽  
Bacterial Interaction ◽  
Arsenic Stress ◽  
Free Media

So far, the relative importance of the plant and its microbiome in the development of early stages of plant seedling growth under arsenic stress has not been studied. To test the role of endophytic bacteria in increasing plant success under arsenic stress, gnotobiotic seeds of J. montana were inoculated with two endophytic bacteria: Pantoea conspicua MC-K1 (PGPB and As resistant bacteria) and Arthrobacter sp. MC-D3A (non-helper and non-As resistant bacteria) and an endobacteria mixture. In holobiotic seedlings (with seed-vectored microbes intact), neither the capacity of germination nor development of roots and lateral hairs was affected at 125 μM As(V). However, in gnotobiotic seedlings, the plants are negatively impacted by absence of a microbiome and presence of arsenic, resulting in reduced growth of roots and root hairs. The inoculation of a single PGPB (P. conspicua-MCK1) shows a tendency to the recovery of the plant, both in arsenic enriched and arsenic-free media, while the inoculation with Arthrobacter sp. does not help in the recovery of the plants. Inoculation with a bacterial mixture allows recovery of plants in arsenic free media; however, plants did not recover under arsenic stress, probably because of a bacterial interaction in the mixture.

scholarly journals Role of infochemical mediated zooplankton grazing in a phytoplankton competition model

2013 ◽  
Vol 16 ◽  
pp. 41-50 ◽  
Author(s):  
Nicola D. Lewis ◽  
Mark N. Breckels ◽  
Michael Steinke ◽  
Edward A. Codling
Keyword(s):  
Competition Model ◽  
Zooplankton Grazing

scholarly journals Efficacy of Clarithromycin Depends on the Bacterial Density in Clarithromycin-Heteroresistant Helicobacter pylori Infections: An In Situ Detected Susceptibility and Quantitative Morphometry-Based Retrospective Study

2021 ◽  
Vol 27 ◽  
Author(s):  
Jewel Ju Ea Kim ◽  
Ildikó Kocsmár ◽  
György Miklós Buzás ◽  
Ildikó Szirtes ◽  
Orsolya Rusz ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Retrospective Study ◽  
Bacterial Population ◽  
Tissue Sample ◽  
Bacterial Density ◽  
Resistant Bacteria ◽  
Hybridization Technique ◽  
Predictive Role

The global rise in clarithromycin (Cla) resistance is considered to be the main contributor of Helicobacter pylori (Hp) eradication failures. In nearly half of the Cla-resistant Hp infections, Cla-susceptible bacteria are simultaneously present with the Cla-resistant ones (Cla-heteroresistance). The proportion of resistant bacteria in the bacterial population (R-fraction) and its predictive role for the use of Cla-based therapies in Cla-heteroresistant infections has not yet been investigated. Our retrospective study analyzed gastric biopsy samples of 62 Hp-positive patients with Cla-heteroresistant infection. Fluorescence In Situ Hybridization technique was used to visualize the coexistence of resistant and susceptible bacteria within one tissue sample. R-fraction was quantified on multichannel microimages by digital morphometry. Resistant bacteria had a patchy distribution within the whole bacterial population causing high diversity among the investigated areas. Patients were subdivided into two major groups according to whether a Cla-based eradication attempt was conducted before or after the biopsy sampling. R-fraction was significantly lower among cases having only one previous Cla-based eradication attempt vs. those that had multiple previous eradications, including at least one Cla-containing therapy (0.41 vs. 0.89, p = 0.0308). Majority of the patients without previous eradication attempt had successful eradication with Cla-containing regimen (59.26%), verified by a negative 13C-urea breath test or control biopsy. Multivariable model indicated that the therapeutic outcome using Cla-based regimens depended on the bacterial density rather than the R-fraction. Our study raises the potential use of Cla-containing eradication therapies in certain Cla-heteroresistant Hp infections, taking into account the possible predictive role of bacterial density.

scholarly journals Endospores and other lysis-resistant bacteria comprise a widely shared core community within the human microbiota

2017 ◽  
Author(s):  
Sean M. Kearney ◽  
Sean M. Gibbons ◽  
Mathilde Poyet ◽  
Thomas Gurry ◽  
Kevin Bullock ◽  
...  
Keyword(s):  
Dietary Fatty Acids ◽  
Resistant Bacteria ◽  
Human Gut ◽  
Environmental Signals ◽  
Human Microbiota ◽  
Disease States ◽  
Culture Independent ◽  
Health And Disease ◽  
Over Time

AbstractEndospore-formers in the human microbiota are well adapted for host-to-host transmission, and an emerging consensus points to their role in determining health and disease states in the gut. The human gut, more than any other environment, encourages the maintenance of endospore formation, with recent culture-based work suggesting that over 50% of genera in the microbiome carry genes attributed to this trait. However, there has been limited work on the ecological role of endospores and other stress-resistant cellular states in the human gut. In fact, there is no data to indicate whether organisms with the genetic potential to form endospores actually form endosporesin situand how sporulation varies across individuals and over time. Here, we applied a culture-independent protocol to enrich for endospores and other stress-resistant cells in human feces to identify variation in these states across people and within an individual over time. We see that cells with resistant states are more likely than those without to be shared among multiple individuals, which suggests that these resistant states are particularly adapted for cross-host dissemination. Furthermore, we use untargeted fecal metabolomics in 24 individuals and within a person over time to show that these organisms respond to shared environmental signals, and in particular, dietary fatty acids, that likely mediate colonization of recently disturbed human guts.

Psychobiological Responses to Competition in Women

2016 ◽  
Author(s):  
Raquel Costa ◽  
Miguel A. Serrano ◽  
Alicia Salvador
Keyword(s):  
Coping Strategies ◽  
Agonistic Behavior ◽  
Functional Role ◽  
Response Pattern ◽  
Competition Model ◽  
Stress Model ◽  
Evolutionary Perspective ◽  
Coping Response ◽  
Challenge Hypothesis

From an evolutionary perspective, questions have been raised about whether women have a psychobiological pattern similar to that of men. In humans, hormonal effects of competition and its outcome have been investigated under the biosocial status hypothesis, which proposes that, after a competition, winners would show increases in testosterone whereas losers would show reductions, and the challenge hypothesis, which emphasizes the functional role of testosterone increases in the spring to promote agonistic behavior related to territoriality and access to females. Subsequently, the coping competition model has defended the study of competition within a more general stress model, considering the psychobiological responses as part of the coping response. This chapter shows that women investigations are increasing in number in recent years and that, in competitive situations, they present coping strategies with a psychobiological response pattern that can be enlightened by the coping competition model.

Global transcriptomic analysis of Lactobacillus delbrueckii subsp. bulgaricus ATCC11842 reveals the role of LDB_RS05285 in the post-acidification of yogurt

2021 ◽  
Author(s):  
Shuai Zhang ◽  
Dongyao Li ◽  
Xin Zhang ◽  
Yongsheng Sun ◽  
Sha Xu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Transcriptomic Analysis ◽  
Lactobacillus Delbrueckii ◽  
Resistant Bacteria ◽  
Lactobacillus Delbrueckii Subsp

During the storage of yogurt, acid-resistant bacteria continue to produce lactic acid (i.e., post-acidification process), leading to undesirable taste and flavor. Many methods have been proposed to inhibit post-acidification. However,...

scholarly journals Arsenic adsorption by Bacterial Extracellular Polymeric Substances

2012 ◽  
Vol 28 (2) ◽  
pp. 80-83 ◽  
Author(s):  
Nazmul Ahsan ◽  
Kashfia Faruque ◽  
Farah Shamma ◽  
Nazrul Islam ◽  
Anwarul A Akhand
Keyword(s):  
Contaminated Soil ◽  
Sodium Arsenite ◽  
Culture Medium ◽  
Extracellular Polymeric Substances ◽  
Soil Samples ◽  
Resistant Bacteria ◽  
Bacterial Isolates ◽  
Arsenic Adsorption ◽  
Arsenic Resistant Bacteria

The main objective of this work was to isolate arsenic resistant bacteria from contaminated soil, followed by screening for their ability to adsorb arsenic. Six bacterial isolates (S1 to S6) were obtained from arsenic contaminated soil samples and among these, five (S1, S2, S3, S5 and S6) were characterized as bacillus and the rest one (S4) was cocci depending on shape. All the isolates except S6 produced extracellular polymeric substances (EPS) in the culture medium and displayed arsenic adsorbing activities demonstrated by adsorption of around 90% from initial concentration of 1 mg/L sodium arsenite. To clarify the role of EPS, we killed the bacteria that produced EPS and used these killed bacteria to see whether they could still adsorb arsenic or not. We found that they could adsorb arsenic similarly like that of EPS produced live bacterial isolates. From the observation it is concluded that these isolates showed potentiality to adsorb arsenic and hence might be used for bioremediation of arsenic. DOI: http://dx.doi.org/10.3329/bjm.v28i2.11821 Bangladesh J Microbiol, Volume 28, Number 2, December 2011, pp 80-83

Selective infection of maize roots by streptomycin-resistant Azospirillum lipoferum and other bacteria

1979 ◽  
Vol 25 (11) ◽  
pp. 1264-1269 ◽  
Author(s):  
Johanna Döbereiner ◽  
Vera Lucia Divan Baldani
Keyword(s):  
Antibiotic Resistance ◽  
Rhizosphere Soil ◽  
Resistant Bacteria ◽  
Root Infection ◽  
Azospirillum Lipoferum ◽  
Wheat Roots ◽  
Low Level ◽  
Maize Roots ◽  
Resistant Strains

The percentage of low-level streptomycin-resistant (20 μg/mL) bacteria in surface-sterilized or washed maize roots was more than a thousand times higher than that in soil populations. There was also a higher incidence of resistant bacteria in rhizosphere as compared with non-rhizosphere soil and bacteria isolated from maize roots were relatively tolerant to several other antibiotics. Azospirillum lipoferum was predominant in surface-sterilized roots of field-grown maize and was low-level streptomycin-resistant while most soil isolates were sensitive. Inoculation with A. brasilense isolated from wheat roots was unsuccessful in terms of establishment even when streptomycin-resistant strains were used. Unidentified causes of specific plant–bacteria affinities therefore transcend the role of antibiotic resistance in maize root infection.

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