Size of Cells and Physicochemical Properties of Membranes are Related to Flavor Production during Sake Brewing in the Yeast Saccharomyces cerevisiae

Ethyl caproate (EC) and isoamyl acetate (IA) are key flavor components of sake. Recently, attempts have been made to increase the content of good flavor components, such as EC and IA, in sake brewing. However, the functions of EC and IA in yeast cells remain poorly understood. Therefore, we investigated the effects of EC and IA using cell-sized lipid vesicles. We also investigated lipid vesicles containing EC and/or caproic acid (CA) as well as IA and/or isoamyl alcohol (IAA). CA and IAA are precursors of EC and IA, respectively, and are important flavors in sake brewing. The size of a vesicle is influenced by flavor compounds and their precursors in a concentration-dependent manner. We aimed to establish the conditions in which the vesicles contained more flavors simultaneously and with different ratios. Interestingly, vesicles were largest in a mixture of 50% of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) with 25% EC and 25% CA or a mixture of 50% DOPC with 25% IA and 25% IAA. The impact of flavor additives on membrane fluidity was also studied using Laurdan generalized polarization. During the production process, flavors may regulate the fluidity of lipid membranes.

Download Full-text

Influence of Ethyl Caproate on the Size of Lipid Vesicles and Yeast Cells

Biomimetics ◽

10.3390/biomimetics5020016 ◽

2020 ◽

Vol 5 (2) ◽

pp. 16 ◽

Cited By ~ 1

Author(s):

Tsuyoshi Yoda ◽

Akira Ogura ◽

Tomoaki Saito

Keyword(s):

Stationary Phase ◽

Cell Size ◽

Lipid Vesicles ◽

Yeast Cells ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Vesicle Size ◽

Flavor Component ◽

Aromatic Components ◽

Ethyl Caproate

Ethyl caproate (EC) is a key flavor component of sake. Recently, in sake brewing, an effort has been underway to increase the content of aromatic components such as EC. However, the function of EC in yeast cells remains poorly understood. Therefore, we investigated the effects of EC using cell-sized lipid vesicles. We found that vesicle size decreases in a concentration-dependent manner when EC is contained in lipid vesicles. Furthermore, yeast experiments showed that a strain producing high quantities of EC in its stationary phase decreased in size during EC production. Given caproic acid’s (CA) status as the esterification precursor of EC in yeast, we also compared lipid vesicles containing CA with those containing EC. We found that CA vesicles were smaller than EC vesicles of the same concentration. These results suggest that EC production may function apparently to maintain cell size.

Download Full-text

Direct interaction of the tau 1 transactivation domain of the human glucocorticoid receptor with the basal transcriptional machinery

Molecular and Cellular Biology ◽

10.1128/mcb.13.1.399-407.1993 ◽

1993 ◽

Vol 13 (1) ◽

pp. 399-407

Author(s):

I J McEwan ◽

A P Wright ◽

K Dahlman-Wright ◽

J Carlstedt-Duke ◽

J A Gustafsson

Keyword(s):

Glucocorticoid Receptor ◽

Protein Interactions ◽

Core Promoter ◽

Specific Interaction ◽

Direct Interaction ◽

Dependent Manner ◽

Transactivation Domain ◽

Yeast Saccharomyces Cerevisiae ◽

Concentration Dependent Manner

We have used a yeast (Saccharomyces cerevisiae) cell free transcription system to study protein-protein interactions involving the tau 1 transactivation domain of the human glucocorticoid receptor that are important for transcriptional transactivation by the receptor. Purified tau 1 specifically inhibited transcription from a basal promoter derived from the CYC1 gene and from the adenovirus 2 major late core promoter in a concentration-dependent manner. This inhibition or squelching was correlated with the transactivation activity of tau 1. Recombinant yeast TATA-binding protein (yTFIID), although active in vitro, did not specifically reverse the inhibitory effect of tau 1. In addition, no specific interaction between tau 1 and yTFIID could be shown in vitro by affinity chromatography. Taken together, these results indicate that the tau 1 transactivation domain of the human glucocorticoid receptor interacts directly with the general transcriptional apparatus through some target protein(s) that is distinct from the TATA-binding factor. Furthermore, this assay can be used to identify interacting factors, since after phosphocellulose chromatography of a whole-cell yeast extract, a fraction that contained an activity which selectively counteracted the squelching effect of tau 1 was found.

Download Full-text

L-Lysine: A Modulator for the Relative Activity of High Molecular Weight (HMW) and Low Molecular Weight(LHW) Urokinase(UK)

10.1055/s-0039-1687222 ◽

1979 ◽

Author(s):

L.L. Shen ◽

W.H. Holleman

Keyword(s):

Molecular Weight ◽

Caproic Acid ◽

Fibrin Clot ◽

Relative Activity ◽

Test Tube ◽

Clot Lysis ◽

Dependent Manner ◽

Plasma Clot ◽

Concentration Dependent Manner ◽

The Difference

L-Lysine(Lys), in a concentration dependent manner, progressively inhibited UK-activated lysis of human plasma clots as demonstrated by Ploug test-tube method and elastometric measurements. Lys was more effective with HMW UK than LMW UK, and the effect of Lys with LMW UK from tissue culture and urine sources was the same. Epsilon amino caproic acid(EACA) and tranexamic acid(TXA) were stronger inhibitors but inhibited HMW and LMW UK-induced lysis to the same degree. Elastometric measurements showed that Lys inhibition was not due to its interference with the initial clotting process nor to the reduction of clot rigidity. Amidolytic assays using chromogenic substrates showed that Lys had no direct effect, on UK, and that Lys enhanced the activation of the native Glu-plasminogen(Pg) by LMW UK, but not the activation by HMW UK. When the substrate was human fibrin clots, Lys enhanced the lysis induced by LMW UK while the lysis induced by HMW UK was inhibited; however, the extent of enhancement and inhibition was limited. We concluded that the mode of Lys action is not identical to that of EACA or TXA, and that the stronger Lys inhibition of plasma clot lysis as compared to fibrin clot lysis is due to the potentiation of plasma fibrinolytic inhibitors by Lys. The difference In effect of Lys on HMW and LMW UK-induced lyels is likely due to a partial conformation change of Glu-Pg molecule upon Lys binding. The relatively moderate interaction of Lys with Glu-Fg results In a mildly modified UK substrate which reacts preferentially with the enzyme smaller in size.

Download Full-text

Forced Expression of Keratin 16 Alters the Adhesion, Differentiation, and Migration of Mouse Skin Keratinocytes

Molecular Biology of the Cell ◽

10.1091/mbc.11.10.3315 ◽

2000 ◽

Vol 11 (10) ◽

pp. 3315-3327 ◽

Cited By ~ 39

Author(s):

Matthew Wawersik ◽

Pierre A. Coulombe

Keyword(s):

Mouse Skin ◽

Cellular Level ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Keratin 16 ◽

Skin Keratinocytes ◽

Steady State Levels ◽

And Migration ◽

Mouse Skin Keratinocytes ◽

The Impact

Injury to the skin results in an induction of keratins K6, K16, and K17 concomitant with activation of keratinocytes for reepithelialization. Forced expression of human K16 in skin epithelia of transgenic mice causes a phenotype that mimics several aspects of keratinocyte activation. Two types of transgenic keratinocytes, with forced expression of either human K16 or a K16-C14 chimeric cDNA, were analyzed in primary culture to assess the impact of K16 expression at a cellular level. High K16-C14-expressing and low K16-expressing transgenic keratinocytes behave similar to wild type in all aspects tested. In contrast, high K16-expressing transgenic keratinocytes show alterations in plating efficiency and calcium-induced differentiation, but proliferate normally. Migration of keratinocytes is reduced in K16 transgenic skin explants compared with controls. Finally, a subset of high K16-expressing transgenic keratinocytes develops major changes in the organization of keratin filaments in a time- and calcium concentration-dependent manner. These changes coincide with alterations in keratin content while the steady-state levels of K16 protein remain stable. We conclude that forced expression of K16 in progenitor skin keratinocytes directly impacts properties such as adhesion, differentiation, and migration, and that these effects depend upon determinants contained within its carboxy terminus.

Download Full-text

The cytoprotective effects of bilirubin and biliverdin on rat hepatocytes and human erythrocytes and the impact of albumin

Biochemistry and Cell Biology ◽

10.1139/o91-123 ◽

1991 ◽

Vol 69 (12) ◽

pp. 828-834 ◽

Cited By ~ 41

Author(s):

Tai-Wing Wu ◽

Doug Carey ◽

Jun Wu ◽

Hiroshi Sugiyama

Keyword(s):

Rat Hepatocytes ◽

Human Erythrocytes ◽

Red Cells ◽

Peroxyl Radicals ◽

Blood Levels ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Hepatocyte Necrosis ◽

The Impact ◽

First Time

The hypothesis that unconjugated bilirubin and biliverdin are cytoprotective antioxidants has been examined for the first time in systems containing cells. In primary rat hepatocytes exposed to xanthine oxidase and hypoxanthine, bilirubin (0–60 μM) failed to prolong cell survival. In contrast, biliverdin (20–100 μM) markedly delayed hepatocyte necrosis in a concentration-dependent manner. When 0.3 mM of albumin was present, bilirubin (0–50 μM) became protective of hepatocytes, while biliverdin was less dramatically enhanced in its cytoprotective effect. In human erythrocytes exposed to peroxyl radicals, bilirubin and biliverdin inhibited 50% cell lysis at lower concentrations than Trolox and ascorbate, respectively. Albumin alone appeared less cytoprotective in red cells than in hepatocytes, but its presence enhanced the effects of both pigments on erythrocytes. Of probable physiologic relevance, bilirubin with albumin present or biliverdin alone protected hepatocytes substantially (and to a lesser extent red cells) at the normal blood levels of bilirubin (3.4–26 μM). Moreover, the fact that the pigments are cytoprotective at higher bilirubin levels (e.g., 50–100 μM) tempts the speculation that they may be circulating cytoprotectors of overlooked importance in jaundice.Key words: cytoprotection, biliverdin, bilirubin, albumin.

Download Full-text

Cell-free Expression of Proton-Coupled Folate Transporter in the Presence of Nanodiscs

10.1101/2021.05.19.444806 ◽

2021 ◽

Author(s):

Hoa Quynh Do ◽

Carla M Bassil ◽

Elizabeth I Andersen ◽

Michaela Jansen

Keyword(s):

Tumor Cells ◽

Plasma Membranes ◽

In Vitro Translation ◽

Translation System ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

E Coli ◽

Membrane Scaffold ◽

The Impact

The Proton-Coupled Folate Transporter (PCFT) is a transmembrane transport protein that controls the absorption of dietary folates in the small intestine. PCFT also mediates uptake of chemotherapeutically used antifolates into tumor cells. PCFT has been identified within lipid rafts observed in phospholipid bilayers of plasma membranes, a micro environment that is altered in tumor cells. The present study aimed at investigating the impact of different lipids within Lipid-protein nanodiscs (LPNs), discoidal lipid structures stabilized by membrane scaffold proteins, to yield soluble PCFT expression in an E. coli lysate-based cell-free transcription/translation system. In the absence of detergents or lipids, we observed PCFT quantitatively as precipitate in this system. We then explored the ability of LPNs to support solubilized PCFT expression when present during in-vitro translation. LPNs consisted of either dimyristoyl phosphatidylcholine (DMPC), palmitoyl-oleoyl phosphatidylcholine (POPC), or dimyristoyl phosphatidylglycerol (DMPG). While POPC did not lead to soluble PCFT expression, both DMPG and DMPC supported PCFT translation directly into LPNs, the latter in a concentration dependent manner. The results obtained through this study provide insights into the lipid preferences of PCFT. Membrane-embedded or solubilized PCFT will enable further studies with diverse biophysical approaches to enhance the understanding of the structure and molecular mechanism of folate transport through PCFT.

Download Full-text

(R,S)-Ketamine Metabolites (R,S)-norketamine and (2S,6S)-hydroxynorketamine Increase the Mammalian Target of Rapamycin Function

Anesthesiology ◽

10.1097/aln.0000000000000285 ◽

2014 ◽

Vol 121 (1) ◽

pp. 149-159 ◽

Cited By ~ 76

Author(s):

Rajib K. Paul ◽

Nagendra S. Singh ◽

Mohammed Khadeer ◽

Ruin Moaddel ◽

Mitesh Sanghvi ◽

...

Keyword(s):

Parent Compound ◽

Mammalian Target Of Rapamycin ◽

Mtor Pathway ◽

Target Of Rapamycin ◽

Dependent Manner ◽

Α7 Nicotinic Acetylcholine Receptor ◽

Concentration Dependent Manner ◽

Pheochromocytoma Cells ◽

The Impact

Abstract Background: Subanesthetic doses of (R,S)-ketamine are used in the treatment of neuropathic pain and depression. In the rat, the antidepressant effects of (R,S)-ketamine are associated with increased activity and function of mammalian target of rapamycin (mTOR); however, (R,S)-ketamine is extensively metabolized and the contribution of its metabolites to increased mTOR signaling is unknown. Methods: Rats (n = 3 per time point) were given (R,S)-ketamine, (R,S)-norketamine, and (2S,6S)-hydroxynorketamine and their effect on the mTOR pathway determined after 20, 30, and 60 min. PC-12 pheochromocytoma cells (n = 3 per experiment) were treated with escalating concentrations of each compound and the impact on the mTOR pathway was determined. Results: The phosphorylation of mTOR and its downstream targets was significantly increased in rat prefrontal cortex tissue by more than ~2.5-, ~25-, and ~2-fold, respectively, in response to a 60-min postadministration of (R,S)-ketamine, (R,S)-norketamine, and (2S,6S)-hydroxynorketamine (P < 0.05, ANOVA analysis). In PC-12 pheochromocytoma cells, the test compounds activated the mTOR pathway in a concentration-dependent manner, which resulted in a significantly higher expression of serine racemase with ~2-fold increases at 0.05 nM (2S,6S)-hydroxynorketamine, 10 nM (R,S)-norketamine, and 1,000 nM (R,S)-ketamine. The potency of the effect reflected antagonistic activity of the test compounds at the α7-nicotinic acetylcholine receptor. Conclusions: The data demonstrate that (R,S)-norketamine and (2S,6S)-hydroxynorketamine have potent pharmacological activity both in vitro and in vivo and contribute to the molecular effects produced by subanesthetic doses of (R,S)-ketamine. The results suggest that the determination of the mechanisms underlying the antidepressant and analgesic effects of (R,S)-ketamine requires a full study of the parent compound and its metabolites.

Download Full-text

Interaction of Graphene Oxide Modified with Linear and Branched PEG with Monocytes Isolated from Human Blood

Nanomaterials ◽

10.3390/nano12010126 ◽

2021 ◽

Vol 12 (1) ◽

pp. 126

Author(s):

Pavel Khramtsov ◽

Maria Bochkova ◽

Valeria Timganova ◽

Anton Nechaev ◽

Sofya Uzhviyuk ◽

...

Keyword(s):

Graphene Oxide ◽

Immune Cells ◽

Human Peripheral Blood ◽

Oxide Surface ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Composition And Structure ◽

Luminescent Signal ◽

Ros Formation ◽

The Impact

Multiple graphene-based therapeutics have recently been developed, however potential risks related to the interaction between nanomaterials and immune cells are still poorly understood. Therefore, studying the impact of graphene oxide on various populations of immune cells is of importance. In this work, we aimed to investigate the effects of PEGylated graphene oxide on monocytes isolated from human peripheral blood. Graphene oxide nanoparticles with lateral sizes of 100–200 nm and 1–5 μm were modified with linear and branched PEG (GO-PEG). Size, elemental composition, and structure of the resulting nanoparticles were characterized. We confirmed that PEG was successfully attached to the graphene oxide surface. The influence of GO-PEG on the production of reactive oxygen species (ROS), cytokines, phagocytosis, and viability of monocytes was studied. Uptake of GO-PEG by monocytes depends on PEG structure (linear or branched). Branched PEG decreased the number of GO-PEG nanoparticles per monocyte. The viability of monocytes was not altered by co-cultivation with GO-PEG. GO-PEG decreased the phagocytosis of Escherichia coli in a concentration-dependent manner. ROS formation by monocytes was determined by measuring luminol-, lucigenin-, and dichlorodihydrofluorescein-dependent luminescence. GO-PEG decreased luminescent signal probably due to inactivation of ROS, such as hydroxyl and superoxide radicals. Some types of GO-PEG stimulated secretion of IL-10 by monocytes, but this effect did not correlate with their size or PEG structure.

Download Full-text

Polarization and cell-fate decision facilitated by the adaptor Ste50 in Saccharomyces cerevisiae

10.1101/2021.10.29.466449 ◽

2021 ◽

Author(s):

Nusrat Sharmeen ◽

Chris Law ◽

Cunle Wu

Keyword(s):

Cell Fate ◽

Critical Role ◽

Time Lapse ◽

Yeast Cells ◽

Cell Cortex ◽

Dependent Manner ◽

Pheromone Response ◽

Concentration Dependent Manner ◽

Directional Growth ◽

Fate Decision

Polarization or directional growth is a major morphological change that occurs in yeast cells during pheromone response to mate with the opposite partner. In the pheromone signaling pathway, the adaptor Ste50 is required to bind MAP3K Ste11 for proper polarization; cells lacking Ste50 are impaired in polarization. Direct involvement of Ste50 in the polarization process has not been explored systematically. Here, we used single-cell fluorescent time-lapse microscopy to characterize Ste50 involvement in the establishment of cell polarity. We found early localization of Ste50 patches on the cell cortex that mark the point of shmoo initiation, these polarity sites move, and patches remain associated with the growing shmoo tip in a pheromone concentration-dependent manner until shmoo maturation. By quantitative analysis we show that polarization corelates with the rising levels of Ste50 enabling rapid individual cell responses to pheromone that corresponds to a critical level of Ste50 at the initial G1 phase. Suggesting Ste50 to be a pheromone responsive gene. We exploited the quantitative differences in the pattern of Ste50 expression to corelate with the cell-cell phenotypic heterogeneity showing Ste50 involvement in the cellular differentiation choices. Taken together, these findings present spatiotemporal localization of Ste50 during yeast polarization, suggesting that Ste50 is a component of the polarisome, and plays a critical role in regulating the polarized growth of shmoo during pheromone response.

Download Full-text

EGT2 gene transcription is induced predominantly by Swi5 in early G1.

Molecular and Cellular Biology ◽

10.1128/mcb.16.7.3264 ◽

1996 ◽

Vol 16 (7) ◽

pp. 3264-3274 ◽

Cited By ~ 61

Author(s):

B Kovacech ◽

K Nasmyth ◽

T Schuster

Keyword(s):

Cell Cycle ◽

Transcriptional Activation ◽

Cell Separation ◽

S Phase ◽

Dependent Manner ◽

Yeast Saccharomyces Cerevisiae ◽

Concentration Dependent Manner ◽

A Cell ◽

Cycle Dependent ◽

Ho Gene

In a screen for cell cycle-regulated genes in the yeast Saccharomyces cerevisiae, we have identified a gene, EGT2, which is involved in cell separation in the G1 stage of the cell cycle. Transcription of EGT2 is tightly regulated in a cell cycle-dependent manner. Transcriptional levels peak at the boundary of mitosis and early G1 The transcription factors responsible for EGT2 expression in early G1 are Swi5 and, to a lesser extent, Ace2. Swi5 is involved in the transcriptional activation of the HO gene during late G1 and early S phase, and Ace2 induces CTS1 transcription during early and late G1 We show that Swi5 activates EGT2 transcription as soon as it enters the nucleus at the end of mitosis in a concentration-dependent manner. Since Swi5 is unstable in the nucleus, its level drops rapidly, causing termination of EGT2 transcription before cells are committed to the next cell cycle. However, Swi5 is still able to activate transcription of HO in late G1 in conjunction with additional activators such as Swi4 and Swi6.

Download Full-text