Use of polyvinyl alcohol as a cell immobilization matrix for copper biosorption by yeast cells

In this work, we compared the performance of a new method of cell immobilization in a novel matrix for biosorption. Yeast cells were entrapped in a polyvinyl alcohol (PVA) matrix, based on an adapted iterative freeze-thaw-freeze process. Spherical and uniform beads were produced, and SEM micrographs confirmed that the cells were uniformly dispersed within the PVA matrix. Further experiments revealed that the use of PVA as the immobilization matrix conferred better mechanical and chemical properties than the commonly used calcium alginate matrix. Experiments also showed that the PVA matrix gave rise to a lower mass transfer resistance than the alginate matrix. Finally, it was established that PVA-yeast biosorbent beads could be regenerated using dilute hydrochloric acid (10mM) and reused for at least five biosorption cycles with virtually no decrease in its bisorption capacity. Different metal/biosorbent in PVA-immobilized systems are currently being investigated.

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Development of a cell immobilization technique with polyvinyl alcohol for diesel remediation in seawater

International Biodeterioration & Biodegradation ◽

10.1016/j.ibiod.2016.05.022 ◽

2016 ◽

Vol 113 ◽

pp. 397-407 ◽

Cited By ~ 9

Author(s):

Pao-Wen Grace Liu ◽

Dun-Sheng Yang ◽

Jyun-Yu Tang ◽

Han-Wei Hsu ◽

Chih-Hung Chen ◽

...

Keyword(s):

Polyvinyl Alcohol ◽

Cell Immobilization ◽

A Cell

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REGULATORY MECHANISMS OF CELLULAR RESPIRATION

The Journal of General Physiology ◽

10.1085/jgp.34.2.211 ◽

1950 ◽

Vol 34 (2) ◽

pp. 211-224 ◽

Cited By ~ 17

Author(s):

E. S. Guzman Barron ◽

Maria Isabel Ardao ◽

Marion Hearon

Keyword(s):

Acetic Acid ◽

Pyruvic Acid ◽

No Oxidation ◽

Yeast Cells ◽

Acid Formation ◽

Cellular Respiration ◽

Acid Oxidase ◽

Acid Solutions ◽

Fluoroacetic Acid ◽

A Cell

The rate of the aerobic metabolism of pyruvic acid by bakers' yeast cells is determined mainly by the amount of undissociated acid present. As a consequence, the greatest rate of oxidation was observed at pH 2.8. Oxidation, at a slow rate, started at pH 1.08; at pH 9.4 there was no oxidation at all. The anaerobic metabolism, only a fraction of the aerobic, was observed only in acid solutions. There was none at pH values higher than 3. Pyruvic acid in the presence of oxygen was oxidized directly to acetic acid; in the absence of oxygen it was metabolized mainly by dismutation to lactic and acetic acids, and CO2. Acetic acid formation was demonstrated on oxidation of pyruvic acid at pH 1.91, and on addition of fluoroacetic acid. Succinic acid formation was shown by addition of malonic acid. These metabolic pathways in a cell so rich in carboxylase may be explained by the arrangement of enzymes within the cell, so that carboxylase is at the center, while pyruvic acid oxidase is located at the periphery. Succinic and citric acids were oxidized only in acid solutions up to pH 4. Malic and α-ketoglutaric acids were not oxidized, undoubtedly because of lack of penetration.

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Nanocellulose-based mechanically stable immobilization matrix for enhanced ethylene production: A framework for photosynthetic solid-state cell factories

Green Chemistry ◽

10.1039/d1gc00502b ◽

2021 ◽

Author(s):

Ville Rissanen ◽

Sindhujaa Vajravel ◽

Sergey Kosourov ◽

Suvi Arola ◽

Eero Kontturi ◽

...

Keyword(s):

Solid State ◽

Ethylene Production ◽

Cell Immobilization ◽

Cell Factory ◽

Cell Factories ◽

Solid State Cell ◽

Immobilization Matrix

Cell immobilization is a promising approach to create efficient photosynthetic cell factories for sustainable chemicals production. Here, we demonstrate a novel photosynthetic solid-state cell factory design for sustainable biocatalytic ethylene...

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Immobilization of fish chromatophores for use as a micro-biosensor for biological toxins

Hemijska industrija ◽

10.2298/hemind0312605m ◽

2003 ◽

Vol 57 (12) ◽

pp. 605-610 ◽

Cited By ~ 1

Author(s):

Ljiljana Mojovic ◽

Goran Jovanovic

Keyword(s):

Cell Attachment ◽

Cell Immobilization ◽

Betta Splendens ◽

Microbial Pathogens ◽

Fish Cell ◽

First Order Kinetics ◽

Microcarrier Bead ◽

Color Response ◽

A Cell ◽

Selection Of

Chromatophores isolated from the Siamese fighting fish, Betta splendens represent a class of living cells that provide a vivid color response to microbial pathogens and environmental toxins. The selection of the most appropriate microcarrier and the development of the optimal technique for the chromatophore immobilization in order to enable directed transport of the sensor cells throughout microchannels of the biosensor, as well to preserve the cell survival and its functionality was studied. Microcarriers derived from glass, polystyrene and gelatin (collagen) were tested as substrates for chromatophore attachement. Gelatin microcarriers were found to be the most suitable, due to high attachment efficiency (95% of attached cells), preservation of the cell viability and enhanced cell sensitivity. The optimum conditions for fish cell immobilization on collagen microcarriers were determined based on the cell-to-microcarrier bead ratio and the pH of the solution. The rate of cell attachment to the gelatin microcarrier followed first-order kinetics. Pretreatment of the gelatin beads with fibronectin, known as a cell attachment-promoting agent, resulted in a 10% higher attachment rate constant (k).

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Physiological function of Flo11p domains and the particular role of amyloid core sequences of this adhesin in Saccharomyces cerevisiae

10.1101/2021.04.01.438097 ◽

2021 ◽

Author(s):

Clara Bouyx ◽

Marion Schiavone ◽

Marie-Ange Teste ◽

Etienne Dague ◽

Nathalie Sieczkowski ◽

...

Keyword(s):

Cell Wall ◽

Amyloid Β ◽

Surface Hydrophobicity ◽

Yeast Cells ◽

Invasive Growth ◽

Specific Domain ◽

A Genome ◽

A Cell ◽

Cellular Aggregates

Flocculins are a family of glycosylated proteins that provide yeast cells with several properties such as biofilm formation, flocculation, invasive growth or formation of velum. These proteins are similarly organised with a N-terminal (adhesion) domain, a stalk-like central B-domain with several repeats and a C-terminal sequence carrying a cell wall anchor site. They also contain amyloid β-aggregation-prone sequences whose functional role is still unclear. In this work, we show that Flo11p differs from other flocculins by the presence of unique amyloid-forming sequences, whose the number is critical in the formation of adhesion nanodomains under a physical shear force. Using a genome editing approach to identify the function of domains in Flo11p phenotypes, we show that the formation of cellular aggregates whose density increases with the number of amyloid sequences cannot be attributed to a specific domain of Flo11p. The same is true for plastic adhesion and surface hydrophobicity the intensity of which depends mainly on the abundance of Flo11p on the cell surface. In contrast, the N and C domains of Flo11p are essential for invasive growth in agar, whereas a reduction in the number of repeats of the B domain weakens this phenotype. However, expression of FLO11 alone is not sufficient to trigger this invasion phenotype. Finally, we show that this flocculin contributes to the integrity of the cell wall.

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Three proteins required for early steps in the protein secretory pathway also affect nuclear envelope structure and cell cycle progression in fission yeast

Journal of Cell Science ◽

10.1242/jcs.115.2.421 ◽

2002 ◽

Vol 115 (2) ◽

pp. 421-431

Author(s):

Anna Matynia ◽

Sandra S. Salus ◽

Shelley Sazer

Keyword(s):

Cell Cycle ◽

Nuclear Envelope ◽

Fission Yeast ◽

Cell Cycle Progression ◽

Secretory Pathway ◽

Yeast Cells ◽

Ran Gtpase ◽

A Cell ◽

Cell Cycle Block ◽

Er Membrane

The Ran GTPase is an essential protein that has multiple functions in eukaryotic cells. Fission yeast cells in which Ran is misregulated arrest after mitosis with condensed, unreplicated chromosomes and abnormal nuclear envelopes. The fission yeast sns mutants arrest with a similar cell cycle block and interact genetically with the Ran system. sns-A10, sns-B2 and sns-B9 have mutations in the fission yeast homologues of S. cerevisiae Sar1p, Sec31p and Sec53p, respectively, which are required for the early steps of the protein secretory pathway. The three sns mutants accumulate a normally secreted protein in the endoplasmic reticulum (ER), have an increased amount of ER membrane, and the ER/nuclear envelope lumen is dilated. Neither a post-ER block in the secretory pathway, nor ER proliferation caused by overexpression of an integral ER membrane protein, results in a cell cycle-specific defect. Therefore, the arrest seen in sns-A10, sns-B2 and sns-B9 is most likely due to nuclear envelope defects that render the cells unable to re-establish the interphase organization of the nucleus after mitosis. As a consequence, these mutants are unable to decondense their chromosomes or to initiate of the next round of DNA replication.

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Decondensation of Xenopus sperm chromatin using Saccharomyces cerevisiae whole-cell extractsThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y05-042 ◽

2006 ◽

Vol 84 (3-4) ◽

pp. 451-458

Author(s):

Troy A.A. Harkness

Keyword(s):

Rnase A ◽

Yeast Cells ◽

Micrococcal Nuclease ◽

Sperm Chromatin ◽

Temperature Sensitive ◽

Whole Cell ◽

Multiple Systems ◽

Cell Extracts ◽

A Cell ◽

Chromosome Decondensation

Biochemical studies using highly condensed Xenopus sperm chromatin and protein extracts prepared from multiple systems have lead to the identification of conserved proteins involved in chromosome decondensation. However, mutations to these proteins are unavailable as the systems used are not amenable to genetic studies. We took a genetic approach to isolating chromosome decondensation mutants by incubating Xenopus sperm chromatin with whole-cell extracts prepared from the Hartwell library of random temperature sensitive (ts) yeast cells. We show that decondensation of Xenopus sperm chromatin using wild type yeast extracts was rapid, ATP- and extract-dependent, and resistant to heat, N-ethylmaleimide, protease K, RNase A, and micrococcal nuclease. From 100 mutant extracts screened, we obtained one strain, referred to as rmc4, that was chromosome decondensation defective. The mutant was slow growing and exhibited germination defects. Low concentrations of rmc4 extract would eventually decondense sperm heads, and fractionation of the mutant extract produced a decondensation competent fraction, suggesting the presence of an overactive inhibitor in rmc4 cells. We performed a multicopy suppressor screen that identified PDE2, a gene encoding a protein that inhibits protein kinase A (PKA) activity. As PKA was previously shown in human cells to maintain condensed chromatin, our results suggest that PKA activity is elevated in rmc4 cells, causing a decondensation defect. Thus, our experiments reveal that yeast encodes an evolutionarily conserved chromosome decondensation activity that can be genetically manipulated.

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Chronological aging leads to apoptosis in yeast

The Journal of Cell Biology ◽

10.1083/jcb.200310014 ◽

2004 ◽

Vol 164 (4) ◽

pp. 501-507 ◽

Cited By ~ 397

Author(s):

Eva Herker ◽

Helmut Jungwirth ◽

Katharina A. Lehmann ◽

Corinna Maldener ◽

Kai-Uwe Fröhlich ◽

...

Keyword(s):

Apoptotic Cell ◽

Selective Advantage ◽

Yeast Cells ◽

Unicellular Organism ◽

Chronological Aging ◽

Beneficial Effects ◽

Yeast Cultures ◽

A Cell ◽

Cell Suicide

During the past years, yeast has been successfully established as a model to study mechanisms of apoptotic regulation. However, the beneficial effects of such a cell suicide program for a unicellular organism remained obscure. Here, we demonstrate that chronologically aged yeast cultures die exhibiting typical markers of apoptosis, accumulate oxygen radicals, and show caspase activation. Age-induced cell death is strongly delayed by overexpressing YAP1, a key transcriptional regulator in oxygen stress response. Disruption of apoptosis through deletion of yeast caspase YCA1 initially results in better survival of aged cultures. However, surviving cells lose the ability of regrowth, indicating that predamaged cells accumulate in the absence of apoptotic cell removal. Moreover, wild-type cells outlast yca1 disruptants in direct competition assays during long-term aging. We suggest that apoptosis in yeast confers a selective advantage for this unicellular organism, and demonstrate that old yeast cells release substances into the medium that stimulate survival of the clone.

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Yeast cell-free system that catalyses joint-molecule formation in a Rad51p- and Rad52p-dependent fashion

Biochemical Journal ◽

10.1042/bj3470363 ◽

2000 ◽

Vol 347 (2) ◽

pp. 363-368 ◽

Cited By ~ 1

Author(s):

Vijayalakshmi NAGARAJ ◽

David NORRIS

Keyword(s):

Homologous Recombination ◽

Specific Activity ◽

Yeast Cells ◽

Active Components ◽

Free System ◽

Cell Free System ◽

Molecule Formation ◽

A Cell

One of the central reactions of homologous recombination is the invasion of a single strand of DNA into a homologous duplex to form a joint molecule. Here we describe the isolation of a cell-free system from meiotic yeast cells that catalyses joint-molecule formation in vitro. The active components in the system required ATP and homologous DNA and operated in both 0.5 and 13 mM MgCl2. When the cell-free system was prepared from rad51/rad51 and rad52/rad52 mutants and joint-molecule formation was assayed at 0.5 mM MgCl2, the specific activity decreased to 6% and 13.8% respectively of the wild-type level. However, when the same mutant extracts were premixed, joint-molecule formation increased 4-8-fold, i.e. the mutant extracts exhibited complementation in vitro. These results demonstrated that Rad51p and Rad52p were required for optimal joint-molecule formation at 0.5 mM MgCl2. Intriguingly, however, Rad51p and Rad52p seemed to be more dispensable at higher concentrations of MgCl2 (13 mM). Further purification of the responsible activity has proven problematical, but it did flow through a sizing column as a single peak (molecular mass 1.2 MDa) that was co-eluted with Rad51p and RFA, the eukaryotic single-stranded DNA-binding protein. All of these characteristics are consistent with the known properties of the reaction in vivo and suggest that the new cell-free system will be suitable for purifying enzymes involved in homologous recombination.

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