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Sizes of yeast strain cells in two situations. (A) Typical images of yeast. Only alive cells (such as those labeled (p)) are counted. Cells in budding (such as those labeled (r)) were also excluded from the count. (B) Size distributions. Dark gray represents yeast in slant state, and light gray represents yeast in stationary phase. Over 30 cells were counted for the calculation of average size, with standard errors shown as error bars. (* P < 0.05).
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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 decrea...
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Context 1
... cell size trends were based on counts and measurements of cells stained with methylene blue and observed under a microscope (Olympus BX53, Japan). Dead cells (such as (q) in Figure 4A) were not counted. Budding cells (such as (r) in Figure 4A) were also excluded because size and count were too difficult to objectively define for budding cells. ...
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... cells (such as (q) in Figure 4A) were not counted. Budding cells (such as (r) in Figure 4A) were also excluded because size and count were too difficult to objectively define for budding cells. It was confirmed that the relative ratio of budding vs non-budding cells was not significantly different between Mahoroba-Hana and Mahoroba-Gin strains. ...
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... trends of growth curve of each strain grown in synthetic YNB medium are shown in Figure 5. At the slant state, sizes of these two types of yeast were almost equal ( Figure 4B, dark gray bar). In the case of MahorobaHana, the size at stationary phase was increased. ...
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... the case of MahorobaHana, the size at stationary phase was increased. In contrast, Mahoroba-Gin size at stationary phase was reduced ( Figure 4B, light gray). Our institute reported previously that Mahoroba-Gin has higher productivity than Mahoroba-Hana, with values of EC concentration as 5.0 and 1.3 ppm, respectively, at the same condition [18,19]. ...
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Wickerhamomyces anomalus is conducive to the synthesis of ester compounds in brewing the Chinese liquor Baijiu ; esters are crucial for the quality of Baijiu . In this study, simulated solid-state fermentation for Baijiu production was used to explore whether artificial addition of W. anomalus could improve the flavor substance in Baijiu , and the...
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 lip...
Citations
... The author's research team investigated the flavors EC, CA, IA, IAA, and IVA to examine their influence on sake production and brewing processes. These flavors exhibit varying strengths and have been found to impact the size of lipid vesicles and their concentration [28][29][30]. These studies aimed to investigate the impact of specific flavors and functional compounds on the size changes of cell-sized lipid vesicles, with the goal of exploring their potential for evaluating the quality of beverages. ...
... Interestingly, PB2 was also found to increase the size of lipid vesicles. In the present study, the effects of these functional materials in beverages were compared based on the results of previous studies [28][29][30][31]. This study aims to contribute to our understanding of the interaction between membranes and functional compounds, providing valuable insights in this field. ...
... Subsequently, various lipid vesicles, including giant unilamellar vesicles and model membranes/liposomes, were prepared. The natural swelling of dry lipid films was performed following a modified version of a method previously published by our research group [28][29][30][31]. ...
By investigating the hydrophobic properties and functional components including ethyl caproate (EC), caproic acid (CA), isoamyl acetate (IA), isoamyl alcohol (IAA), isovaleraldehyde (IVA), and procyanidin B2 (PB2) in beverages, one can incorporate them with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipids to create cell-sized lipid vesicles. The aim of this study was to explore the correlation between the concentration of flavors or functional compounds and the size of the lipid vesicles. It was observed that EC, CA, IA, and IAA decreased the size of lipid vesicles. In contrast, IVA and PB2 increased their size. To comprehend this correlation, both the chemical structure of these compounds in relation to DOPC membranes and the fluidity of the membranes were considered. The size of the lipid vesicles was influenced by the molecular interactions between the compounds and DOPC. Those were caused by, in particular, the balance between hydrophobicity and hydrophilicity. Compounds with higher hydrophobicity tended to decrease the size of the lipid vesicles, whereas compounds with greater hydrophilicity had the opposite effect, leading to an increase in size. These findings suggest that the size of lipid vesicles can serve as a potential indicator for rapidly evaluating the concentration of these components in beverages.
... Observations and analyses had to be performed separately, and observational data had to be re-monitored when software analysis was not suitable. Cell counts have also been performed empirically using spectrophotometric absorbance measurements [4,5], and both cell number and size have been optically measured [6]. However, cell count has been emphasized in experiments, while cell size has been largely neglected. ...
... Yeast was cultured in YNB medium, as reported in the literature [4,5], at 30 • C. After 3 days, it was plated on an agar medium and maintained at 30 • C; subsequently, it was cultured in a slant medium from single colonies. ...
... Yeast was cultured in YNB medium, as reported in the literature [4,5], 3 days, it was plated on an agar medium and maintained at 30 °C; subseq cultured in a slant medium from single colonies. The yeast was then transfe slant medium back to the YNB medium and incubated for an additional 3 Successful cell cultivation was confirmed by OD 660 measurement using a eter (UV-1800; Shimadzu, Kyoto, Japan) to reach the stationary phase. ...
Yeast produces flavor components as by-products of fermentation. Such components, which account for considerable yeast quality value, may influence cell membrane fluidity and regulate cell size. In this study, yeast cell size was measured using various methods, and cell sizes were characterized for each strain of yeast. Herein, a method for measuring the cell size and automatically acquiring the cell area was proposed using inexpensive methylene blue staining and a versatile digital microscope to automatically acquire the cell area. To evaluate the efficiency, data on cell length and area were compared using the conventional and proposed methods. Additionally, the advantages of automated measurement and the ability to count cell numbers in the future are discussed through the acquisition of cell size data, which would be required for microfabrication and cell fabrication techniques. Although there are various candidate methods for evaluating the properties of each yeast strain, the present technique may be useful for evaluating the productivity of flavor components and selecting a yeast strain for producing food and drink products with high commodity values.
... Several different types of liposomes were prepared, including giant unilamellar vesicles (GUV) and model membranes/liposomes. A slightly modified version of the method of natural swelling from dry lipid films was used as outlined in previous studies [9,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. Since unilamellar vesicle formation is highly sensitive to the preparation conditions, samples were prepared under well-controlled physical conditions, as described below. ...
Positively charged ion species and charged lipids play specific roles in biochemical processes, especially those involving cell membranes. The cell membrane and phase separation domains are attractive research targets to study signal transduction. The phase separation structure and functions of cell-sized liposomes containing charged lipids and cholesterol have been investigated earlier, and the domain structure has also been studied in a membrane model, containing the yeast sterol ergosterol. The present study investigates phase-separated domain structure alterations in membranes containing charged lipids when cholesterol is substituted with ergosterol. This study finds that ergosterol increases the homogeneity of membranes containing charged lipids. Cholesterol-containing membranes are more sensitive to a charged state, and ergosterol-containing liposomes show lower responses to charged lipids. These findings may improve our understanding of the differences in both yeast and mammalian cells, as well as the interactions of proteins with lipids during signal transduction.
... Bacillus spp., Alcaligenes spp., and Pseudomonos spp., of bacteria and Penicillium spp., Fusarium spp., Aspergillus spp., of fungi are screened as candidates for large scale of the production of lipases mentioned above [77]. However, the selection and modification of highyield ethyl caproate strains mainly focus on Saccharomyces cerevisiae [78][79][80]and Monascus purpureus [81][82][83]. In our study, we established the closer relationship between 21 novel genus of bacterium (such as Aeriscardovia, Atopobium and Paracocccus) and the formation of ethyl hexanoate after P value adjust (Fig 4B). ...
Huangjiu is a national alcoholic beverage in China. Millet has congenital advantages in development and utilization of nutrient. Brewing Huangjiu with millet can increase the value of millet. Microbial community plays crucial roles in millet Huangjiu fermentation. Flavor compounds reflect the quality and health function of Huangjiu. The flavor compounds of Huangjiu are complex and their formation is closely associated with microorganisms, but the relationship between them during fermentation has been unknown. In this research, this relationship during millet Huangjiu fermentation were deeply investigated. Totally 86 volatile compounds were detected. Bacillus , Weissella , Paenibacillus , Klebsiella , Prevotella was investigated as the dominant microbes through high-throughput sequencing. 537 correlations between major flavor compounds and microbes were established to reflect the dynamic change during millet Huangjiu fermentation. The top five dominant genus of flavor producing microbes were Chryseobacterium , Sporolactobacillus , Psychrobacter , Sphingobium and Anoxybacillus . The content of malic acid and citric acid was gradually improved all through the millet Huangjiu fermentation. Malic acid and citric acid generated from millet Huangjiu fermentation shows healthy properties as liver protection and eliminating fatigue. Our research provides essential information on microbial community succession and the flavor formation during millet Huangjiu fermentation, and beneficial for development of Huangjiu products.
... As lipid vesicles have properties similar to cell membranes, artificial cell-sized lipid vesicles have been used as cell model membranes to reveal physicochemical properties of membranes that are important for life processes. Therefore, we have used a vesicle system formed by a single phospholipid component to study the physical-chemical effects of the flavor components [5]. Of note, good flavor components and their precursors influenced the behavior of the lipid vesicles, i.e., their size and fluidity, in a concentration-dependent manner. ...
... Recently, we produced lipid vesicles containing EC and its precursor CA and found that these vesicles were small [5]. The diameter of vesicles affects several physicochemical properties [22,23]. ...
... The diameter of vesicles affects several physicochemical properties [22,23]. According to previous research, EC and CA should interact with lipid membranes [5]. We have postulated that different membrane properties correspond to different flavors; this could enable rapid detection and quantification of flavors in the future. ...
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.
This study focuses on procyanidins, which are functional polyphenols from apple. Procyanidin B2 (PB2), a known procyanidin dimer, is the standard procyanidin compound. PB2 stimulates the lipid metabolic pathway by preventing lipid absorbance. Here, the interaction between PB2 and the lipid membrane of cell‐sized liposomes was investigated. The study found that adding PB2 to the cell‐sized liposomes increased the liposome size and changed their fluidity. Therefore, the possibility of procyanidin improving lipid absorbance through the transformation of the membrane receptors or channel activity was discussed.
Sake (a traditional Japanese alcoholic beverage) contains ethyl caproate (EC), which enhances its economic value. Isovaleraldehyde (IVA) is also a well‐known flavoring agent in alcoholic beverages, which some people enjoy. Recently, studies revealed that EC decreased the size of homogenous 1,2‐Dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC) liposomes whereas IVA increased their size. Cholesterol (Chol) and ergosterol were previously referred to as animal and fungus sterols. For the first time, this study demonstrated the phase behavior of the membrane in cell‐sized liposomes containing EC and IVA. After adding EC, the solid ordered/liquid disordered (Ld) and liquid ordered (Lo)/Ld phase separation in DOPC/dipalmitoyl‐sn‐glycero‐3‐phosphocholine/cholesterol or ergosterol ternary membranes decreased, but the Lo/Ld phase separation decreased after adding IVA. Biophysics, physiological, and application aspects of EC and IVA evaluation were discussed. The findings of this study not only enhance our understanding of the function of flavors but also provide rapid and cost effective performance for the measurement.
Recent studies indicated that ergosterol (Erg) helps form strongly ordered lipid domains in membranes that depend on their chemical characters. However, direct evidence of concentration-dependent interaction of Erg with lipid membranes has not been reported. We studied the Erg concentration-dependent changes in the phase behaviors of membranes using cell-sized liposomes containing 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). We observed the concentration range of phase separation in ternary membranes was significantly wider when Erg rather than cholesterol (Chol) was used as the sterol component. We used machine learning for the first time to analyze microscopic images of cell-sized liposomes and identify phase-separated structures. The automated method was successful in identifying homogeneous membranes but performance remained data-limited for the identification of phase separation domains characterized by more complex features.
