Dynamics of the Autochthonous and Contaminant Bacterial Colonization of Lakes (Lake of Cadagno and Lake of Lugano as model systems)

Non-viable preparations of probiotics, as whole-cell postbiotics, attract increasing interest because of their intrinsic technological stability, and their functional properties, such as immune system modulation, gut barrier maintenance, and protection against pathogens. However, reports on Bifidobacteria-derived postbiotics remain scarce. This study aims to demonstrate the functional properties of a heat-treated (HT), non-viable, Bifidobacterium longum strain, CECT-7347, a strain previously selected for its anti-inflammatory phenotype and ability to improve biomarkers of intestinal integrity in clinical trials. The study used the nematode Caenorhabditis elegans and HT-29 cell cultures as eukaryotic model systems. Our results show that HT-CECT-7347 preserves the capacity to protect against oxidative stress damage, while it also reduces acute inflammatory response and gut-barrier disruption, and inhibits bacterial colonization, by activating pathways related to innate immune function. These findings highlight the interest of the ingredient as a novel postbiotic and pave the way to broaden the range of HT-CECT-7347 applications in gut health.

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Competition for space during bacterial colonization of a surface

Journal of The Royal Society Interface ◽

10.1098/rsif.2015.0608 ◽

2015 ◽

Vol 12 (110) ◽

pp. 20150608 ◽

Cited By ~ 26

Author(s):

Diarmuid P. Lloyd ◽

Rosalind J. Allen

Keyword(s):

Bacterial Colonization ◽

Model Systems ◽

Ecological Interactions ◽

Bacterial Populations ◽

Competition For Space ◽

Colonization Success ◽

Bacterial Model ◽

Lag Times ◽

Empty Habitat ◽

As Effects

Competition for space is ubiquitous in the ecology of both microorganisms and macro-organisms. We introduce a bacterial model system in which the factors influencing competition for space during colonization of an initially empty habitat can be tracked directly. Using fluorescence microscopy, we follow the fate of individual Escherichia coli bacterial cell lineages as they undergo expansion competition (the race to be the first to colonize a previously empty territory), and as they later compete at boundaries between clonal territories. Our experiments are complemented by computer simulations of a lattice-based model. We find that both expansion competition, manifested as differences in individual cell lag times, and boundary competition, manifested as effects of neighbour cell geometry, can play a role in colonization success, particularly when lineages expand exponentially. This work provides a baseline for investigating how ecological interactions affect colonization of space by bacterial populations, and highlights the potential of bacterial model systems for the testing and development of ecological theory.

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Nuclear coiled bodies and the nucleolus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100167834 ◽

1994 ◽

Vol 52 ◽

pp. 20-21

Author(s):

K. Brasch ◽

J. Williams ◽

D. Gallo ◽

T. Lee ◽

R. L. Ochs

Keyword(s):

Mouse Liver ◽

Nuclear Body ◽

Nuclear Bodies ◽

Model Systems ◽

Coiled Body ◽

Rrna Processing ◽

Malignant Cells ◽

Sm Proteins ◽

Coiled Bodies ◽

Unique Protein

Though first described in 1903 by Ramon-y-Cajal as silver-staining “accessory bodies” to nucleoli, nuclear bodies were subsequently rediscovered by electron microscopy about 30 years ago. Nuclear bodies are ubiquitous, but seem most abundant in hyperactive and malignant cells. The best studied type of nuclear body is the coiled body (CB), so termed due to characteristic morphology and content of a unique protein, p80-coilin (Fig.1). While no specific functions have as yet been assigned to CBs, they contain spliceosome snRNAs and proteins, and also the nucleolar protein fibrillarin. In addition, there is mounting evidence that CBs arise from or are generated near the nucleolus and then migrate into the nucleoplasm. This suggests that as yet undefined links may exist, between nucleolar pre-rRNA processing events and the spliceosome-associated Sm proteins in CBs.We are examining CB and nucleolar changes in three diverse model systems: (1) estrogen stimulated chick liver, (2) normal and neoplastic cells, and (3) polyploid mouse liver.

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Microtubule Dynamics and Organelle Transport in Reticulomyxa

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158510 ◽

1990 ◽

Vol 48 (3) ◽

pp. 194-195

Author(s):

Yih-Tai Chen ◽

Ursula Euteneuer ◽

Ken B. Johnson ◽

Michael P. Koonce ◽

Manfred Schliwa

Keyword(s):

Plasma Membrane ◽

Light Microscopy ◽

Cytoplasmic Dynein ◽

Living Cells ◽

Microtubule Dynamics ◽

Model Systems ◽

Organelle Transport ◽

Biochemical Characteristics ◽

Dependent Transport

The application of video techniques to light microscopy and the development of motility assays in reactivated or reconstituted model systems rapidly advanced our understanding of the mechanism of organelle transport and microtubule dynamics in living cells. Two microtubule-based motors have been identified that are good candidates for motors that drive organelle transport: kinesin, a plus end-directed motor, and cytoplasmic dynein, which is minus end-directed. However, the evidence that they do in fact function as organelle motors is still indirect.We are studying microtubule-dependent transport and dynamics in the giant amoeba, Reticulomyxa. This cell extends filamentous strands backed by an extensive array of microtubules along which organelles move bidirectionally at up to 20 μm/sec (Fig. 1). Following removal of the plasma membrane with a mild detergent, organelle transport can be reactivated by the addition of ATP (1). The physiological, pharmacological and biochemical characteristics show the motor to be a cytoplasmic form of dynein (2).

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Microstructural observations of the “Wustite-Spinel” coexistence following quenching of cation-excess spinels, Ni2(1+x)Ti1-xO4

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178422 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1058-1059

Author(s):

Ian M. Anderson ◽

Arnulf Muan ◽

C. Barry Carter

Keyword(s):

Film Growth ◽

Spinel Phase ◽

Model Systems ◽

Ion Milling ◽

Coexistence Of Phases ◽

Nonequilibrium Conditions ◽

Diffraction Patterns ◽

Spinel Structures ◽

Highly Porous ◽

Standard Techniques

Oxide mixtures which feature a coexistence of phases with the wüstite and spinel structures are considered model systems for the study of solid-state reaction kinetics, phase boundaries, and thin-film growth, and such systems are especially suited to TEM studies. (In this paper, the terms “wüstite” and “spinel” will refer to phases of those structure types.) The study of wüstite-spinel coexistence has been limited mostly to systems near their equilibrium condition, where the assumptions of local thermodynamic equilibrium are valid. The cation-excess spinels of the type Ni2(1+x)Ti1-xO4, which reportedly exist only above 1375°C4, provide an excellent system for the study of wüstite-spinel coexistence under highly nonequilibrium conditions. The nature of these compounds has been debated in the literature. X-ray and neutron powder diffraction patterns have been used to advocate the existence of a single-phase, non- stoichiometric spinel. TEM studies of the microstructure have been used to suggest equilibrium coexistence of a stoichiometric spinel, Ni2TiO4, and a wüstite phase; this latter study has shown a coexistence of wüstite and spinel phases in specimens thought to have been composed of a single, non- stoichiometric spinel phase. The microstructure and nature of this phase coexistence is the focus of this study. Specimens were prepared by ball-milling a mixture of NiO and TiO2 powders with 10 wt.% TiO2. The mixture was fired in air at 1483°C for 5 days, and then quenched to room temperature. The aggregate thus produced was highly porous, and needed to be infiltrated prior to TEM sample preparation, which was performed using the standard techniques of lapping, dimpling, and ion milling.

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