Phenotypic Response of Wolbachia pipientis in a Cell-Free Medium

Wolbachia, an obligate intracellular bacterium estimated to infect millions of arthropod species worldwide, is currently being utilized in novel control strategies to limit the transmission of Dengue and Zika viruses. A limitation for Wolbachia-based control approaches is the difficulty of transferring Wolbachia to novel hosts and the lack of tools for the genetic transformation of Wolbachia due to the inability to culture Wolbachia outside the insect host cell in an axenic media. Here, we applied extracellular Wolbachia to phenotypic microarrays to measure the metabolic response of Wolbachia in media formulations with different pH levels and supplementation with Casamino acids. Results suggested a pH of 6.5–6.8 and showed that the supplementation of 1 mg/mL casamino acids increased the survival and longevity of Wolbachia in an axenic medium. In addition, phenotypic microarrays are a useful tool to measure the phenotypic response of Wolbachia under different media conditions, as well as determine specific components that may be required for an axenic medium. This study is an initial step toward the development of a potential Wolbachia axenic culture system.

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Growth of myxamoebae of the cellular slime mould Dictyostelium discoideum in axenic culture

Biochemical Journal ◽

10.1042/bj1190171 ◽

1970 ◽

Vol 119 (2) ◽

pp. 171-174 ◽

Cited By ~ 695

Author(s):

D. J. Watts ◽

J. M. Ashworth

Keyword(s):

Cell Differentiation ◽

Dictyostelium Discoideum ◽

Axenic Culture ◽

Axenic Medium ◽

Cellular Slime Mould ◽

Slime Mould ◽

Solid Media ◽

Cellular Slime

1. A simple axenic medium suitable for the growth of the myxamoebae of a strain of the cellular slime mould Dictyostelium discoideum is described. 2. Procedures suitable for the growth of this strain in liquid and on solid media are described. 3. Conditions suitable for initiating the cell differentiation of myxamoebae grown axenically are described.

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Notes on the biology of some native orchids of Thunder Bay, their endophytes and symbionts

Canadian Journal of Botany ◽

10.1139/b74-059 ◽

1974 ◽

Vol 52 (3) ◽

pp. 451-460 ◽

Cited By ~ 21

Author(s):

Gaëtan Harvais

Keyword(s):

Axenic Culture ◽

Field Studies ◽

Symbiotic Association ◽

Isolation And Identification ◽

Orchid Species ◽

Growing Period ◽

Thunder Bay ◽

The Media ◽

Casamino Acids ◽

Inorganic Components

Field studies were made of eight terrestrial orchid species of the Thunder Bay region during their active growing period. In four of them roots were examined for infection, then isolation and identification of endophytes attempted.Seeds were collected from all species and, along with those of two alien ones, were grown on various media in axenic culture. Their germination and development were studied and described.Seeds were also tested in dixenic cultures with locally isolated endophytes and four fungi known to be good symbionts with other orchids. The nature of infection was finally assessed and discussed.In the field the roots of mature plants of the orchid species differed in their degree of infection and reaction to their endophytes. Only two species of Rhizoctonia were isolated. These are described.In axenic culture, germination of some species was affected by the organic (and inorganic) components of the media, in others it was not. For growth they all responded differently to such components, but most were intolerant of casamino acids, yeast extract, and potato extract. Generally there seemed to be a direct correlation between percentage of germination and amounts of subsequent growth, but a less defined one with the number of cells per seed.In dixenic cultures the orchids responded differently also to the fungi. Their reaction to infection had no relation to their ability to germinate on poor media or to germinate and grow on richer ones. Only one good symbiotic association was established. It was between Goodyera oblongifolia from British Columbia and Rs10, a rice pathogen from Malaysia.The results and their implications are briefly discussed.

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Hybrid force and position control of a conducting tri-layer electro-active polymer actuator

Transactions of the Institute of Measurement and Control ◽

10.1177/0142331216659537 ◽

2016 ◽

Vol 39 (3) ◽

pp. 288-296 ◽

Cited By ~ 4

Author(s):

M Y Coskun ◽

C Sancak ◽

M Itik ◽

G Alici

Keyword(s):

Position Control ◽

Control Strategies ◽

Point Of View ◽

Smith Predictor ◽

Electroactive Polymer ◽

Cell Injection ◽

Injection Process ◽

Polymer Actuator ◽

A Cell ◽

Position Control System

In this study, the displacement and blocking force of the tip point of a cantilevered electro-active polymer (EAP) actuator has been controlled for a cell injection process which consists of approaching, interacting and leaving steps. A vision-based system is used to acquire the tip displacement data for identifying a transfer function model of the actuator and its position control. Discrete time Proportional-Integral controllers are used to control the position and blocking force. A Smith Predictor is utilized in the vision-based position control system to compensate for the time delay due to image processing. Experimental position and blocking force results prove that the proposed control strategies are effective enough to guide the actuator to undertake the cell injection process. This study contributes to the previously published work from the point of view of simultaneously controlling the position and blocking force of the electroactive polymer actuators and widening their application areas.

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Escherichia coli heat-stable enterotoxin: rapid method of purification and some characteristics of the toxin

Infection and Immunity ◽

10.1128/iai.28.2.469-474.1980 ◽

1980 ◽

Vol 28 (2) ◽

pp. 469-474

Author(s):

R Lallier ◽

S Lariviere ◽

S St-Pierre

Keyword(s):

Escherichia Coli ◽

Polyacrylamide Gel Electrophoresis ◽

Coli Strain ◽

Suckling Mice ◽

Heat Stable ◽

Yeast Extract Medium ◽

Schiff Reagent ◽

A Cell ◽

Casamino Acids ◽

Forced Aeration

In this study we used Escherichia coli strain F11(P155) of porcine origin. The heat-stable enterotoxin (ST) was produced with a batch fermentor under agitation (500 rpm) and forced aeration (5 liters/min) in Casamino Acids yeast extract medium containing 0.2% glucose. The pH varied from 7.2 to 7.8. The maximum amount of ST was obtained after 7 h of growth. ST was purified by ammonium sulfate precipitation, ultrafiltration on Amicon membranes, and chromatography in Bio-Gel P-4. The enterotoxin, which was purified approximately 1,000 times, was active at nanogram levels. On 20% polyacrylamide gel electrophoresis, ST exhibited an Rf of 0.6 ST was recovered from the gel slices by eluting in buffer and testing the activity in suckling mice, since no band appeared on the gel after staining with Coomasie brilliant blue R, Schiff reagent, or red oil. ST was resistant at pH 2 to 10 and at 100 degrees C for 15 min, but it was inactivated at 121 degrees C; it did not lose biological activity after treatment with pronase, lipase, or amylase. In suckling mice antiserum obtained from rabbits or goats immunized with ST neutralized the enterotoxin activity of a cell-free supernatant of purified ST.

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New Selectable Marker for Manipulating the Simple Genomes of Mycoplasma Species

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00388-09 ◽

2009 ◽

Vol 53 (10) ◽

pp. 4429-4432 ◽

Cited By ~ 15

Author(s):

Mikkel A. Algire ◽

Carole Lartigue ◽

David W. Thomas ◽

Nacyra Assad-Garcia ◽

John I. Glass ◽

...

Keyword(s):

Selectable Marker ◽

Axenic Culture ◽

Mycoplasma Species ◽

Molecular Tools ◽

Shuttle Vectors ◽

Genetic Manipulations ◽

A Cell ◽

Recognition Elements ◽

Dominant Selectable Marker ◽

Made In

ABSTRACT Over the past several years, significant advances have been made in the molecular genetics of the Mollicutes (the simplest cells that can be grown in axenic culture). Nevertheless, a number of basic molecular tools are still required before genetic manipulations become routine. Here we describe the development of a new dominant selectable marker based on the enzyme puromycin-N-acetyltransferase from Streptomyces alboniger. Puromycin is an antibiotic that mimics the 3′-terminal end of aminoacylated tRNAs and attaches to the carboxyl terminus of growing protein chains. This stops protein synthesis. Because puromycin conscripts rRNA recognition elements that are used by all of the various tRNAs in a cell, it is unlikely that spontaneous antibiotic resistance can be acquired via a simple point mutation—an annoying issue with existing mycoplasma markers. Our codon-optimized cassette confers pronounced puromycin resistance on all five of the mycoplasma species we have tested so far. The resistance cassette was also designed to function in Escherichia coli, which simplifies the construction of shuttle vectors and makes it trivial to produce the large quantities of DNA generally necessary for mycoplasma transformation. Due to these and other features, we expect the puromycin marker to be a widely applicable tool for studying these simple cells and pathogens.

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Single-Cell Adhesion Force Mapping of a Highly Sticky Bacterium in Liquid

10.26434/chemrxiv.14221709 ◽

2021 ◽

Author(s):

Satoshi Ishii ◽

Shogo Yoshimoto ◽

Katsutoshi Hori

Keyword(s):

Cell Surface ◽

Adhesion Force ◽

Quantitative Imaging ◽

Direct Interaction ◽

Acinetobacter Baylyi ◽

Force Microscopy ◽

Strong Adhesion ◽

Force Mapping ◽

A Cell ◽

Casamino Acids

The highly sticky bacterium Acinetobacter sp. Tol 5 adheres to various material surfaces via its cell surface nanofiber protein, AtaA. This adhesiveness has only been evaluated based on the amount of cells adhering to a surface. In this study, the adhesion force mapping of a single Tol 5 cell in liquid using the quantitative imaging mode of atomic force microscopy (AFM) revealed that the strong adhesion of Tol 5 was several nanonewtons, which was outstanding compared with other adhesive bacteria. The adhesion force of a cell became stronger with the increase in AtaA molecules present on the cell surface. Many fibers of peritrichate AtaA molecules simultaneously interact with a surface, strongly attaching the cell to the surface. The adhesion force of a Tol 5 cell was drastically reduced in the presence of 1% casamino acids but not in deionized water (DW), although both liquids decrease the adhesiveness of Tol 5 cells, suggesting that DW and casamino acids inhibit the cell approaching step and the subsequent direct interaction step of AtaA with surfaces, respectively. Heterologous production of AtaA provided non-adhesive Acinetobacter baylyi ADP1 cells with a strong adhesion force to AFM tip surfaces of silicon and gold.

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Studies on the systematics of ectomycorrhizal fungi in axenic culture. II. The enzymatic degradation of selected carbon and nitrogen compounds

Canadian Journal of Botany ◽

10.1139/b90-194 ◽

1990 ◽

Vol 68 (7) ◽

pp. 1522-1530 ◽

Cited By ~ 53

Author(s):

Leonard J. Hutchison

Keyword(s):

Enzyme Activity ◽

Key Words ◽

Ectomycorrhizal Fungi ◽

Enzymatic Degradation ◽

Axenic Culture ◽

Ammonium Phosphate ◽

Nitrogen Compounds ◽

Carbon And Nitrogen ◽

Casamino Acids ◽

Taxonomic Groups

Ninety-six species of ectomycorrhizal fungi from 30 genera were grown on modified Melin–Norkrans agar where the carbon (glucose) or nitrogen (ammonium phosphate dibasic) supply was replaced by cellulose, lignin, pectin, lipid, amylose, gelatin, casamino acids, or urea. Ectomycorrhizal fungi did not appreciably degrade cellulose, lignin, or pectin. The remaining compounds were broken down by representatives of certain taxonomic groups. Lipase was produced by Amanita species, amylase by species of Amanita and Cortinarius, gelatinase by Piloderma, Thelephora, species of Lactarius section Dapetes, and some species of both Amanita and Cortinarius. Casamino acids were degraded by Laccaria, Hebeloma, and some Tricholoma species. Urease was detected in species of Hebeloma and Laccaria. The ability to enzymatically degrade selected carbon and nitrogen compounds have potential as taxonomic characters for the identification of isolates of ectomycorrhizal fungi. The significance of these results are also discussed in relation to the ecology of these fungi. Key words: ectomycorrhizal fungi, enzyme activity, cultures, identification, systematics.

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Arthropod Ground Strata Composition of the Cotton Ecosystem in South-Eastern Queensland, and the Effect of Some Control Strategies.

Australian Journal of Zoology ◽

10.1071/zo9800693 ◽

1980 ◽

Vol 28 (6) ◽

pp. 693 ◽

Cited By ~ 5

Author(s):

AL Bishop ◽

PRB Blood

Keyword(s):

Pest Control ◽

Broad Spectrum ◽

Control Strategies ◽

Abundant Species ◽

Diverse Group ◽

Pitfall Traps ◽

Group 14 ◽

South Eastern ◽

Arthropod Species ◽

Cotton Fields

A record is provided of 23 arthropod species inhabiting the ground strata of cotton fields in south-eastern Queensland. The Coleoptera were the most diverse group (14 species) and Labidura riparia truncata Kirby, and Nala lividipes (Dufour) (both Labiduridae : Dermaptera) were the most abundant species caught in pitfall traps. Changes in the ecosystem in response to different pest control strategies were considered; broad-spectrum insecticide use resulted in the suppression of most species. Resurgence of L. riparia was evident in fields treated with DDT-toxaphene. Possible resurgence of four other species was observed after the removal of insecticide pressure. Several of these species may be of importance because of their predatory function.

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Activin A and ALK4 Identified as Novel Regulators of Epithelial to Mesenchymal Transition (EMT) in Human Epicardial Cells

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.765007 ◽

2021 ◽

Vol 9 ◽

Author(s):

Esther Dronkers ◽

Tessa van Herwaarden ◽

Thomas J van Brakel ◽

Gonzalo Sanchez-Duffhues ◽

Marie-José Goumans ◽

...

Keyword(s):

Epithelial To Mesenchymal Transition ◽

Cardiac Development ◽

Essential Element ◽

Initial Step ◽

Activin A ◽

Embryonic Mouse ◽

Mesenchymal Transition ◽

Epicardial Cells ◽

A Cell ◽

Biochemical Signals

The epicardium, the mesothelial layer covering the heart, is a crucial cell source for cardiac development and repair. It provides cells and biochemical signals to the heart to facilitate vascularization and myocardial growth. An essential element of epicardial behavior is epicardial epithelial to mesenchymal transition (epiMT), which is the initial step for epicardial cells to become motile and invade the myocardium. To identify targets to optimize epicardium-driven repair of the heart, it is vital to understand which pathways are involved in the regulation of epiMT. Therefore, we established a cell culture model for human primary adult and fetal epiMT, which allows for parallel testing of inhibitors and stimulants of specific pathways. Using this approach, we reveal Activin A and ALK4 signaling as novel regulators of epiMT, independent of the commonly accepted EMT inducer TGFβ. Importantly, Activin A was able to induce epicardial invasion in cultured embryonic mouse hearts. Our results identify Activin A/ALK4 signaling as a modulator of epicardial plasticity which may be exploitable in cardiac regenerative medicine.

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Optimal Control of a Cell-to-Cell Fractional-Order Model with Periodic Immune Response for HCV

Symmetry ◽

10.3390/sym13112121 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2121

Author(s):

Xue Yang ◽

Yongmei Su ◽

Huijia Li ◽

Xinjian Zhuo

Keyword(s):

Optimal Control ◽

Immune Response ◽

Combination Therapy ◽

Fractional Order ◽

Control Strategies ◽

Order Model ◽

Reproduction Numbers ◽

A Cell ◽

The Relationship ◽

Two Equilibria

In this paper, a Caputo fractional-order HCV Periodic immune response model with saturation incidence, cell-to-cell and drug control was proposed. We derive two different basic reproductive numbers and their relation with infection-free equilibrium and the immune-exhausted equilibrium. Moreover, there exists some symmetry in the relationship between the two equilibria and the basic reproduction numbers. We obtain the global stability of the infection-free equilibrium by using Lyapunov function and the local stability of the immune-exhausted equilibrium. The optimal control problem is also considered and two control strategies are given; one is for ITX5061 monotherapy, the other is for ITX5061 and DAAs combination therapy. Matlab numerical simulation shows that combination therapy has lower objective function value; therefore, it is worth trying to use combination therapy to treat HCV infection.

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