Effect of light intensity on the correlation between cell mass concentration and optical density in high density culture of a filamentous microorganism

Yoon, Jong Hyun; Shin, Jung Won; Park, Joon Ho; Park, Tai Hyun

doi:10.1007/s11814-015-0012-3

Cited by 4 publications

(4 citation statements)

References 23 publications

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“…Considering the unexpected bi-phasic fluorescence curve observed in both droplets and plates, we conclude that at certain antibiotic concentrations and late incubation stages, the fluorescence intensity is no longer proportional to the biomass as determined by the optical density of the culture. This is further supported by Supplementary Figure S9 and Yoon et al (2015) work.…”

Section: Resultssupporting

confidence: 72%

Population dynamics of cross-protection against β-lactam antibiotics in droplet microreactors

Zhao,

Ruelens,

Farr

et al. 2023

Front. Microbiol.

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IntroductionBacterial strains that are resistant to antibiotics may protect not only themselves, but also sensitive bacteria nearby if resistance involves antibiotic degradation. Such cross-protection poses a challenge to effective antibiotic therapy by enhancing the long-term survival of bacterial infections, however, the current understanding is limited.MethodsIn this study, we utilize an automated nanoliter droplet analyzer to study the interactions between Escherichia coli strains expressing a β-lactamase (resistant) and those not expressing it (sensitive) when exposed to the β-lactam antibiotic cefotaxime (CTX), with the aim to define criteria contributing to cross-protection.ResultsWe observed a cross-protection window of CTX concentrations for the sensitive strain, extending up to approximately 100 times its minimal inhibitory concentration (MIC). Through both microscopy and enzyme activity analyses, we demonstrate that bacterial filaments, triggered by antibiotic stress, contribute to cross-protection.DiscussionThe antibiotic concentration window for cross-protection depends on the difference in β-lactamase activity between co-cultured strains: larger differences shift the ‘cross-protection window’ toward higher CTX concentrations. Our findings highlight the dependence of opportunities for cross-protection on the relative resistance levels of the strains involved and suggest a possible specific role for filamentation.

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Section: Resultssupporting

confidence: 72%

Population dynamics of cross-protection against β-lactam antibiotics in droplet microreactors

Zhao,

Ruelens,

Farr

et al. 2023

Front. Microbiol.

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“…Although this latter is considered quite fast compared to direct measurement of biomass dry weight, depends a lot on sample pretreatment conditions, especially homogenization affecting largely the degree of hyphal fragmentation. Supportive conclusions were drawn by Yoon et al [23], finding that optical density (OD) values were significantly influenced by morphological structures of filaments. Thus, sample treatment has notable effect on the obtainable relationship between dry cell weight and OD.…”

Section: Introductionmentioning

confidence: 53%

Carbohydrate to Itaconic Acid Conversion by Aspergillus terreus and the Evaluation of Process Monitoring Based on the Measurement of CO2

Nemestóthy

Komáromy

Bakonyi

et al. 2019

Waste Biomass Valor

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In this work, itaconic acid (IA) was produced biotechnologically by Aspergillus terreus fungal strain from glucose. The performance of the batch fermentation was kinetically assessed and the maximal IA production potential, maximal production rate and lag-phase time were determined as 28.1 g/L, 3.83 g/L day and 1.52 days, respectively. In addition, the bioprocess was evaluated based on the most frequently used parameters, in particular IA titer (26.3 g/L), yield (0.22 g/g substrate) and productivity (0.1 g/L h), which were comparable to the already published literature. Furthermore, an on-line monitoring system was installed to the fermenter in order to measure the CO 2 content of the bioreactor off-gas. Actually, it was indicated by the results that the CO 2 production could have a linear-like relationship with the quantity of fungal biomass. Hence, the data collected in such a way may have the potential to establish an alternative methodology for the monitoring of biomass growth in the course of the biological transformation taking place.

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“…It is possible that the change in cell shape in the double gene-deleted strain could account for an increased O.D. when compared to the WT or single gene-deleted strains (46,47).…”

Section: Discussionmentioning

confidence: 99%

Functional loss ofrffGandrfbB,encoding dTDP-glucose 4,6-dehydratase, changes colony morphology, cell shape, motility and virulence inSalmonellaTyphimurium

Chakravorty

Banerjee

Joseph

et al. 2023

Preprint

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Lipopolysaccharide (LPS) O antigen and enterobacterial common antigen (ECA) play crucial roles in maintaining the structural integrity of the outer membrane in Gram-negative bacteria. Previous studies conducted with either LPS or ECA mutants have highlighted the importance of these cell surface polysaccharides in the physiology of Salmonella enterica serovar Typhimurium (S. Typhimurium). However, the functional consequences resulting from the abrogation of both O-antigen and ECA synthesis in S. Typhimurium are not well studied. In the present study, we generated single and double gene-deleted mutants of rffG and rfbB, which are paralogs, encoding dTDP-glucose 4,6-dehydratase that catalyze steps in the synthesis of both O-antigen and ECA. The functional loss of both rffG and rfbB (Delta rffG & Delta rfbB), but not in single gene-deleted strains, results in a round cell morphology, smaller colony formation and altered LPS profile. In addition, the Delta rffG & Delta rfbB strain displays defects in outer membrane permeability, causing hypersensitivity to bile and cell wall targeting antibiotics, e.g., meropenem and polymyxin B. Transcriptomic analysis identified flagellar and SPI-1 pathway to be highly down-regulated in the Delta rffG & Delta rfbB strain which leads to impaired swimming and swarming motility and lower adhesion and invasion of HeLa cells. Importantly, the Delta rffG & Delta rfbB strain is less proficient in colonizing Peyers patches, spleen and liver, is unable to induce pro-inflammatory cytokines and is attenuated in both the oral and intra-peritoneal models of S. Typhimurium infection in mice. Overall, this study highlights the importance of rffG and rfbB in maintaining cell wall integrity, colony and cellular morphology, motility and virulence in S. Typhimurium.

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Effect of light intensity on the correlation between cell mass concentration and optical density in high density culture of a filamentous microorganism

Cited by 4 publications

References 23 publications

Population dynamics of cross-protection against β-lactam antibiotics in droplet microreactors

Population dynamics of cross-protection against β-lactam antibiotics in droplet microreactors

Carbohydrate to Itaconic Acid Conversion by Aspergillus terreus and the Evaluation of Process Monitoring Based on the Measurement of CO2

Functional loss ofrffGandrfbB,encoding dTDP-glucose 4,6-dehydratase, changes colony morphology, cell shape, motility and virulence inSalmonellaTyphimurium

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