Illuminate the hidden: in vivo mapping of microscale pH in the mycosphere using a novel whole-cell biosensor

AbstractThe pH of an environment is both a driver and the result of diversity and functioning of microbial habitats such as the area affected by fungal hyphae (mycosphere). Here we used a novel pH-sensitive bioreporter, Synechocystis sp. PCC6803_peripHlu, and ratiometric fluorescence microscopy, to spatially and temporally resolve the mycosphere pH at the micrometre scale. Hyphae of the basidiomycete Coprionopsis cinerea were allowed to overgrow immobilised and homogeneously embedded pH bioreporters in an agarose microcosm. Signals of >700 individual cells in an area of 0.4 × 0.8 mm were observed over time and used to create highly resolved (3 × 3 µm) pH maps using geostatistical approaches. C. cinerea changed the pH of the agarose from 6.9 to ca. 5.0 after 48 h with hyphal tips modifying pH in their vicinity up to 1.8 mm. pH mapping revealed distinct microscale spatial variability and temporally stable gradients between pH 4.4 and 5.8 over distances of ≈20 µm. This is the first in vivo mapping of a mycosphere pH landscape at the microscale. It underpins the previously hypothesised establishment of pH gradients serving to create spatially distinct mycosphere reaction zones.

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Development and substrate specificity screening of an in vivo biosensor for the detection of biomass derived aromatic chemical building blocks

Chemical Communications ◽

10.1039/c6cc04559f ◽

2016 ◽

Vol 52 (76) ◽

pp. 11402-11405 ◽

Cited By ~ 14

Author(s):

Leopoldo F. M. Machado ◽

Neil Dixon

Keyword(s):

Substrate Specificity ◽

Plant Biomass ◽

Building Blocks ◽

Whole Cell ◽

Cellular Processes ◽

Whole Cell Biosensor ◽

Cell Biosensor

To facilitate the screening of chemical, enzymatic, and cellular processes to degrade and valorize plant biomass a whole cell biosensor was developed to detect lignin-derived substrates.

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The Development of Homologous (Canine/Anti-Canine) Antibodies in Dogs with Haemophilia A (Factor VIII Deficiency): A Ten-Year Longitudinal Study

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651541 ◽

1993 ◽

Vol 69 (01) ◽

pp. 021-024 ◽

Cited By ~ 20

Author(s):

Shawn Tinlin ◽

Sandra Webster ◽

Alan R Giles

Keyword(s):

Factor Viii ◽

Canine Model ◽

Significant Inhibition ◽

Human Condition ◽

Haemophilia A ◽

Variable Expression ◽

The Family ◽

Over Time

SummaryThe development of inhibitors to factor VIII in patients with haemophilia A remains as a serious complication of replacement therapy. An apparently analogous condition has been described in a canine model of haemophilia A (Giles et al., Blood 1984; 63:451). These animals and their relatives have now been followed for 10 years. The observation that the propensity for inhibitor development was not related to the ancestral factor VIII gene has been confirmed by the demonstration of vertical transmission through three generations of the segment of the family related to a normal (non-carrier) female that was introduced for breeding purposes. Haemophilic animals unrelated to this animal have not developed functionally significant factor VIII inhibitors despite intensive factor VIII replacement. Two animals have shown occasional laboratory evidence of factor VIII inhibition but this has not been translated into clinical significant inhibition in vivo as assessed by clinical response and F.VIII recovery and survival characteristics. Substantial heterogeneity of inhibitor expression both in vitro and in vivo has been observed between animals and in individual animals over time. Spontaneous loss of inhibitors has been observed without any therapies designed to induce tolerance, etc., being instituted. There is also phenotypic evidence of polyclonality of the immune response with variable expression over time in a given animal. These observations may have relevance to the human condition both in determining the pathogenetic factors involved in this condition and in highlighting the heterogeneity of its expression which suggests the need for caution in the interpretation of the outcome of interventions designed to modulate inhibitor activity.

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Nonparametric detection of changes over time in image data from fluorescence microscopy of living cells

Scandinavian Journal of Statistics ◽

10.1111/sjos.12517 ◽

2021 ◽

Author(s):

Kathrin Bissantz ◽

Nicolai Bissantz ◽

Katharina Proksch

Keyword(s):

Fluorescence Microscopy ◽

Image Data ◽

Living Cells ◽

Nonparametric Detection ◽

Changes Over Time ◽

Over Time

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Prevalence and Photobiology of Photosynthetic Dinoflagellate Endosymbionts in the Nudibranch Berghia stephanieae

Animals ◽

10.3390/ani11082200 ◽

2021 ◽

Vol 11 (8) ◽

pp. 2200

Author(s):

Ruben X. G. Silva ◽

Paulo Cartaxana ◽

Ricardo Calado

Keyword(s):

Food Deprivation ◽

Photosynthetic Efficiency ◽

Rapid Decrease ◽

Complete Loss ◽

Symbiotic Association ◽

Non Invasive ◽

Sea Slugs ◽

Non Destructive ◽

Over Time

Berghia stephanieae is a stenophagous sea slug that preys upon glass anemones, such as Exaiptasia diaphana. Glass anemones host photosynthetic dinoflagellate endosymbionts that sea slugs ingest when consuming E. diaphana. However, the prevalence of these photosynthetic dinoflagellate endosymbionts in sea slugs appears to be short-lived, particularly if B.stephanieae is deprived of prey that host these microalgae (e.g., during bleaching events impacting glass anemones). In the present study, we investigated this scenario, along with food deprivation, and validated the use of a non-invasive and non-destructive approach employing chlorophyll fluorescence as a proxy to monitor the persistence of the association between sea slugs and endosymbiotic photosynthetic dinoflagellates acquired through the consumption of glass anemones. Berghia stephanieae deprived of a trophic source hosting photosynthetic dinoflagellate endosymbionts (e.g., through food deprivation or by feeding on bleached E. diaphana) showed a rapid decrease in minimum fluorescence (Fo) and photosynthetic efficiency (Fv/Fm) when compared to sea slugs fed with symbiotic anemones. A complete loss of endosymbionts was observed within 8 days, confirming that no true symbiotic association was established. The present work opens a new window of opportunity to rapidly monitor in vivo and over time the prevalence of associations between sea slugs and photosynthetic dinoflagellate endosymbionts, particularly during bleaching events that prevent sea slugs from incorporating new microalgae through trophic interactions.

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Burst of Corneal Dendritic Cells during Trastuzumab and Paclitaxel Treatment

Diagnostics ◽

10.3390/diagnostics11050838 ◽

2021 ◽

Vol 11 (5) ◽

pp. 838

Author(s):

Katharina A. Sterenczak ◽

Nadine Stache ◽

Sebastian Bohn ◽

Stephan Allgeier ◽

Bernd Köhler ◽

...

Keyword(s):

Breast Cancer ◽

Dendritic Cells ◽

Cancer Therapy ◽

Adverse Effects ◽

Laser Scanning Microscopy ◽

Sensory Nerves ◽

Confocal Laser ◽

Corneal Nerves ◽

Over Time

During breast cancer therapy, paclitaxel and trastuzumab are both associated with adverse effects such as chemotherapy-induced peripheral neuropathy and other systemic side effects including ocular complications. Corneal nerves are considered part of the peripheral nervous system and can be imaged non-invasively by confocal laser scanning microscopy (CLSM) on the cellular level. Thus, in vivo CLSM imaging of structures of the corneal subbasal nerve plexus (SNP) such as sensory nerves or dendritic cells (DCs) can be a powerful tool for the assessment of corneal complications during cancer treatment. During the present study, the SNP of a breast cancer patient was analyzed over time by using large-scale in vivo CLSM in the course of paclitaxel and trastuzumab therapy. The same corneal regions could be re-identified over time. While the subbasal nerve morphology did not alter significantly, a change in dendritic cell density and an additional local burst within the first 11 weeks of therapy was detected, indicating treatment-mediated corneal inflammatory processes. Ocular structures such as nerves and dendritic cells could represent useful biomarkers for the assessment of ocular adverse effects during cancer therapy and their management, leading to a better visual prognosis.

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Cytosolic Ca2+ measurements by ratiometric fluorescence microscopy in melanoma cells

STAR Protocols ◽

10.1016/j.xpro.2020.100282 ◽

2021 ◽

Vol 2 (1) ◽

pp. 100282

Author(s):

Tiago Rodrigues ◽

Letícia Silva Ferraz

Keyword(s):

Fluorescence Microscopy ◽

Melanoma Cells ◽

Ratiometric Fluorescence

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In vivo praziquantel efficacy of Schistosoma japonicum over time: a systematic review and meta-analysis

Acta Tropica ◽

10.1016/j.actatropica.2021.106048 ◽

2021 ◽

pp. 106048

Author(s):

Qiu-Fu Yu ◽

Jie-Ying Zhang ◽

Meng-Tao Sun ◽

Man-Man Gu ◽

Hui-Ying Zou ◽

...

Keyword(s):

Systematic Review ◽

Schistosoma Japonicum ◽

Meta Analysis ◽

Over Time

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The Role of Mechanical Tension in Neurons

MRS Proceedings ◽

10.1557/proc-1274-qq01-06 ◽

2010 ◽

Vol 1274 ◽

Cited By ~ 1

Author(s):

Taher Saif ◽

Jagannathan Rajagopalan ◽

Alireza Tofangchi

Keyword(s):

Mechanical Response ◽

Mechanical Forces ◽

Active Tension ◽

Mechanical Tension ◽

Deformation Response ◽

Linear Force ◽

Tension Regulation ◽

Over Time

AbstractWe used high resolution micromechanical force sensors to study the in vivo mechanical response of embryonic Drosophila neurons. Our experiments show that Drosophila axons have a rest tension of a few nN and respond to mechanical forces in a manner characteristic of viscoelastic solids. In response to fast externally applied stretch they show a linear force-deformation response and when the applied stretch is held constant the force in the axons relaxes to a steady state value over time. More importantly, when the tension in the axons is suddenly reduced by releasing the external force the neurons actively restore the tension, sometimes close to their resting value. Along with the recent findings of Siechen et al (Proc. Natl. Acad. Sci. USA 106, 12611 (2009)) showing a link between mechanical tension and synaptic plasticity, our observation of active tension regulation in neurons suggest an important role for mechanical forces in the functioning of neurons in vivo.

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Influence of the luxR Regulatory Gene Dosage and Expression Level on the Sensitivity of the Whole-Cell Biosensor to Acyl-Homoserine Lactone

Biosensors ◽

10.3390/bios11060166 ◽

2021 ◽

Vol 11 (6) ◽

pp. 166

Author(s):

Sergey Bazhenov ◽

Uliana Novoyatlova ◽

Ekaterina Scheglova ◽

Vadim Fomin ◽

Svetlana Khrulnova ◽

...

Keyword(s):

Gene Dosage ◽

Regulatory Gene ◽

Homoserine Lactone ◽

Threshold Concentration ◽

Expression Level ◽

Whole Cell ◽

Lux Biosensors ◽

Order Of Magnitude ◽

Whole Cell Biosensor ◽

Cell Biosensor

Aliivibrio fischeri LuxR and Aliivibrio logei LuxR1 and LuxR2 regulatory proteins are quorum sensing transcriptional (QS) activators, inducing promoters of luxICDABEG genes in the presence of an autoinducer (3-oxo-hexanoyl-l-homoserine lactone). In the Aliivibrio cells, luxR genes are regulated by HNS, CRP, LitR, etc. Here we investigated the role of the luxR expression level in LuxI/R QS system functionality and improved the whole-cell biosensor for autoinducer detection. Escherichia coli-based bacterial lux-biosensors were used, in which Photorhabdus luminescensluxCDABE genes were controlled by LuxR-dependent promoters and luxR, luxR1, or luxR2 regulatory genes. We varied either the dosage of the regulatory gene in the cells using additional plasmids, or the level of the regulatory gene expression using the lactose operon promoter. It was shown that an increase in expression level, as well as dosage of the regulatory gene in biosensor cells, leads to an increase in sensitivity (the threshold concentration of AI is reduced by one order of magnitude) and to a two to threefold reduction in response time. The best parameters were obtained for a biosensor with an increased dosage of luxRA. fischeri (sensitivity to 3-oxo-hexanoyl-l-homoserine lactone reached 30–100 pM).

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