In vitro maintenance of a human proximal colon microbiota using the continuous fermentation system P-ECSIM

New biological strategies for the treatment of Salmonella infection are needed in response to the increase in antibiotic-resistant strains. Escherichia coli L1000 and Bifidobacterium thermophilum RBL67 were previously shown to produce antimicrobial proteinaceous compounds (microcin B17 and thermophilicin B67, respectively) active in vitro against a panel of Salmonella strains recently isolated from clinical cases in Switzerland. In this study, two three-stage intestinal continuous fermentation models of Salmonella colonization inoculated with immobilized faeces of a two-year-old child were implemented to study the effects of the two bacteriocinogenic strains compared with a bacteriocin-negative mutant of strain L1000 on Salmonella growth, as well as gut microbiota composition and metabolic activity. Immobilized E. coli L1000 added to the proximal colon reactor showed a low colonization, and developed preferentially in the distal colon reactor independent of the presence of genetic determinants for microcin B17 production. Surprisingly, E. coli L1000 addition strongly stimulated Salmonella growth in all three reactors. In contrast, B. thermophilum RBL67 added in a second phase stabilized at high levels in all reactors, but could not inhibit Salmonella already present at a high level (>107 c.f.u. ml−1) when the probiotic was added. Inulin added at the end of fermentation induced a strong bifidogenic effect in all three colon reactors and a significant increase of Salmonella counts in the distal colon reactor. Our data show that under the simulated child colonic conditions, the microcin B17 production phenotype does not correlate with inhibition of Salmonella but leads to a better colonization of E. coli L1000 in the distal colon reactor. We conclude that in vitro models with complex and complete gut microbiota are required to accurately assess the potential and efficacy of probiotics with respect to Salmonella colonization in the gut.

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Comparative proteomic profiling of newly acquired, virulent and attenuated Neoparamoeba perurans proteins associated with amoebic gill disease

Scientific Reports ◽

10.1038/s41598-021-85988-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kerrie Ní Dhufaigh ◽

Eugene Dillon ◽

Natasha Botwright ◽

Anita Talbot ◽

Ian O’Connor ◽

...

Keyword(s):

Bacterial Community Composition ◽

Illumina Miseq ◽

Proteomic Profiling ◽

Farmed Fish ◽

Liquid Chromatography Tandem Mass ◽

Proteome Database ◽

Gill Disease ◽

The Impact ◽

In Vitro Maintenance

AbstractThe causative agent of amoebic gill disease, Neoparamoeba perurans is reported to lose virulence during prolonged in vitro maintenance. In this study, the impact of prolonged culture on N. perurans virulence and its proteome was investigated. Two isolates, attenuated and virulent, had their virulence assessed in an experimental trial using Atlantic salmon smolts and their bacterial community composition was evaluated by 16S rRNA Illumina MiSeq sequencing. Soluble proteins were isolated from three isolates: a newly acquired, virulent and attenuated N. perurans culture. Proteins were analysed using two-dimensional electrophoresis coupled with liquid chromatography tandem mass spectrometry (LC–MS/MS). The challenge trial using naïve smolts confirmed a loss in virulence in the attenuated N. perurans culture. A greater diversity of bacterial communities was found in the microbiome of the virulent isolate in contrast to a reduction in microbial community richness in the attenuated microbiome. A collated proteome database of N. perurans, Amoebozoa and four bacterial genera resulted in 24 proteins differentially expressed between the three cultures. The present LC–MS/MS results indicate protein synthesis, oxidative stress and immunomodulation are upregulated in a newly acquired N. perurans culture and future studies may exploit these protein identifications for therapeutic purposes in infected farmed fish.

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Changes in the volatile composition of apple and apple/pear ciders affected by the different dilution rates in the continuous fermentation system

LWT ◽

10.1016/j.lwt.2021.111630 ◽

2021 ◽

pp. 111630

Author(s):

Jarosław Kliks ◽

Joanna Kawa-Rygielska ◽

Alan Gasiński ◽

Justyna Rębas ◽

Antoni Szumny

Keyword(s):

Continuous Fermentation ◽

Volatile Composition ◽

Fermentation System

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Postnatal development of colonic electrolyte transport in rabbits

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1990.258.3.g447 ◽

1990 ◽

Vol 258 (3) ◽

pp. G447-G453 ◽

Cited By ~ 2

Author(s):

E. V. O'Loughlin ◽

D. M. Hunt ◽

D. Kreutzmann

Keyword(s):

Chloride Transport ◽

Age Groups ◽

Serum Cortisol ◽

Distal Colon ◽

Proximal Colon ◽

Transport Studies ◽

Age Related ◽

Serum Aldosterone ◽

Group Transport

Postnatal changes in adrenal gluco- and mineralocorticoid secretion and colonic sodium and chloride transport were examined. New Zealand White rabbits, age 10-14, 18-22, and 25-30 days, and adult animals (6-10 wk) were studied. Serum cortisol, corticosterone, aldosterone, and mucosal Na(+)-K(+)-ATPase activities were measured in each age group. Transport studies were performed in vitro under short-circuited conditions in distal colon at all age groups and in proximal colon in days 10-14 and 18-22 and in adult animals. Serum glucocorticoids varied little until after day 30 when they rose to adult levels. On the other hand, serum aldosterone levels were two- to threefold higher in days 10-14 and 18-22 animals but fell to adult levels by day 25. In distal colon, amiloride-inhibitable electrogenic Na+ absorption was present at all ages but was significantly greater (P less than 0.01) in days 10-14 (3.8 +/- 0.5 mu eq.cm-2.h-1) and 18-22 (4.2 +/- 0.4) rabbits compared with adults (1.9 +/- 0.4) but not day 25-30 (2.8 +/- 0.5). In proximal colon, Na+ absorption was significantly higher (P less than 0.05) in day 10-14 (1.6 +/- 0.5 mu eq.cm-2.h-1) compared with day 18-22 (-0.2 +/- 0.5) and adults (0.06 +/- 0.5) and was amiloride insensitive. Neither chloride transport nor mucosal Na(+)-K(+)-ATPase demonstrated significant age-related changes in either region of colon. These results indicate that both proximal and distal colonic Na+ transport undergoes postnatal changes. In distal but not proximal colon these changes appear to be regulated by circulating aldosterone probably by increasing apical membrane permeability to Na+.

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Defining the early stages of intestinal colonisation by whipworms

10.1101/2020.08.21.261586 ◽

2020 ◽

Author(s):

María A. Duque-Correa ◽

David Goulding ◽

Claire Cormie ◽

Catherine Sharpe ◽

Judit Gali Moya ◽

...

Keyword(s):

Intestinal Epithelium ◽

Early Stage ◽

Proximal Colon ◽

Host Cells ◽

Parasitic Nematodes ◽

Metazoan Parasites ◽

Multiple Cells ◽

First Time

ABSTRACTHundreds of millions of people are infected with whipworms (Trichuris trichiura), large metazoan parasites that live in the caecum and proximal colon. Whipworms inhabit distinct multi-intracellular epithelial burrows that have been described as syncytial tunnels. However, the interactions between first-stage (L1) larvae and the host epithelia that determine parasite invasion and establishment in the syncytium remain unclear. In vivo experiments investigating these events have been severely hampered by the limited in situ accessibility to intracellular infective larvae at the bottom of the crypts of Lieberkühn, and the lack of genetic tools such as fluorescent organisms that are readily available for other pathogens but not parasitic nematodes. Moreover, cell lines, which do not mimic the complexity of the intestinal epithelium, have been unsuccessful in supporting infection by whipworm larvae. Here, we show that caecaloids grown in an open crypt-like conformation recapitulate the caecal epithelium. Using this system, we establish in vitro infections with T. muris L1 larvae for the first-time, and provide clear evidence that syncytial tunnels are formed at this early stage. We show that larval whipworms are completely intracellular but woven through multiple cells. Using the caecaloids, we are able to visualise the pathways taken by the larvae as they burrow through the epithelial cells. We also demonstrate that larvae degrade the mucus layers overlaying the epithelium, enabling them to access the cells below. We show that early syncytial tunnels are composed of enterocytes and goblet cells that are alive and actively interacting with the larvae during the first 24 h of the infection. Progression of infection results in damage to host cells and by 72 h post-infection, we show that desmosomes of cells from infected epithelium widen and some host cells appear to become liquified. Collectively, our work unravels processes mediating the intestinal epithelium invasion by whipworms and reveals new specific interactions between the host and the parasite that allow the whipworm to establish on its multi-intracellular niche. Our study demonstrates that caecaloids can be used as a relevant in vitro model to investigate the infection biology of T. muris during the early colonisation of its host.

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Assessing prebiotic effects of resistant starch on modulating gut microbiota with an in vivo animal model and an in vitro semi-continuous fermentation model

10.31274/etd-180810-2954 ◽

2010 ◽

Cited By ~ 1

Author(s):

Li Li

Keyword(s):

Animal Model ◽

Gut Microbiota ◽

Resistant Starch ◽

Continuous Fermentation ◽

In Vivo Animal Model ◽

Fermentation Model

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Simulating the Hydrodynamic Conditions of the Human Ascending Colon: A Digital Twin of the Dynamic Colon Model

Pharmaceutics ◽

10.3390/pharmaceutics14010184 ◽

2022 ◽

Vol 14 (1) ◽

pp. 184

Author(s):

Michael Schütt ◽

Connor O’Farrell ◽

Konstantinos Stamatopoulos ◽

Caroline L. Hoad ◽

Luca Marciani ◽

...

Keyword(s):

Contractile Activity ◽

Proximal Colon ◽

Oral Dosage ◽

Shear Rates ◽

Digital Twin ◽

Solid Oral Dosage Forms ◽

Vitro Model ◽

In Silico Models ◽

Oral Dosage Forms

The performance of solid oral dosage forms targeting the colon is typically evaluated using standardised pharmacopeial dissolution apparatuses. However, these fail to replicate colonic hydrodynamics. This study develops a digital twin of the Dynamic Colon Model; a physiologically representative in vitro model of the human proximal colon. Magnetic resonance imaging of the Dynamic Colon Model verified that the digital twin robustly replicated flow patterns under different physiological conditions (media viscosity, volume, and peristaltic wave speed). During local contractile activity, antegrade flows of 0.06–0.78 cm s−1 and backflows of −2.16–−0.21 cm s−1 were measured. Mean wall shear rates were strongly time and viscosity dependent although peaks were measured between 3.05–10.12 s−1 and 5.11–20.34 s−1 in the Dynamic Colon Model and its digital twin respectively, comparable to previous estimates of the USPII with paddle speeds of 25 and 50 rpm. It is recommended that viscosity and shear rates are considered when designing future dissolution test methodologies for colon-targeted formulations. In the USPII, paddle speeds >50 rpm may not recreate physiologically relevant shear rates. These findings demonstrate how the combination of biorelevant in vitro and in silico models can provide new insights for dissolution testing beyond established pharmacopeial methods.

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Application of biomaterials to in vitro pluripotent stem cell disease modeling of the skeletal system

Journal of Materials Chemistry B ◽

10.1039/c5tb02645h ◽

2016 ◽

Vol 4 (20) ◽

pp. 3482-3489 ◽

Cited By ~ 6

Author(s):

Giuliana E. Salazar-Noratto ◽

Frank P. Barry ◽

Robert E. Guldberg

Keyword(s):

Stem Cells ◽

Pluripotent Stem Cells ◽

Disease Modeling ◽

Genetic Manipulation ◽

Embryonic Stem ◽

Cell Disease ◽

Skeletal System ◽

System P ◽

Induced Pluripotent

Disease-specific pluripotent stem cells can be derived through genetic manipulation of embryonic stem cells or by reprogramming somatic cells (induced pluripotent stem cells).

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Sodium transport by lamb proximal colon measured during early postnatal development

The Journal of Agricultural Science ◽

10.1017/s0021859600041228 ◽

1982 ◽

Vol 98 (1) ◽

pp. 155-159 ◽

Cited By ~ 3

Author(s):

M. W. Smith ◽

P. S. James

Keyword(s):

Postnatal Development ◽

Sodium Transport ◽

Short Circuit ◽

Short Circuit Current ◽

Proximal Colon ◽

Early Postnatal Development ◽

The Third ◽

Electrolyte Absorption ◽

Chloride Absorption

SUMMARYProximal colons taken from lambs up to 3 weeks after birth were shown to transport both sodium and chloride from lumen to blood when incubated in vitro.Sodium transport fell into three phases during postnatal development. The first covered the period from birth to 3 days of age when sodium transport was high and equal to that calculated from measurement of short-circuit current. The second was seen in 5- and 7-day-old lambs where the short-circuit current was low and the net transport of sodium was negligible. The third was seen in 2-3-week-old lambs where sodium transport was high, but the short-circuit current was low.Chloride absorption by colons taken from 1-day-old lambs appeared to be in exchange for an anion, possibly bicarbonate. Chloride absorption by colons taken from 3-week-old lambs appeared to be electrogenie or coupled directly to the transport of sodium.A possible explanation for the failure of electrolyte absorption by colons taken from 5- and 7-day-old lambs is discussed.

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