Methionine and Glycine Stabilize Mitochondrial Activity in Sake Yeast During Ethanol Fermentation

Dodatak aminokiselina u fermentacijsku podlogu utječe na rast i aktivnost kvasca, a zadržavanje aktivnosti mitohondrija tijekom alkoholnog vrenja je kritično za aktivnost pivskog kvasca. Međutim, mehanizam djelovanja aminokiselina u fermentacijskoj podlozi i njihov utjecaj na aktivnost mitohondrija pivskog kvasca tijekom vrenja još uvijek nije poznat. U ovom radu smo utvrdili da aminokiseline u fermentacijskoj podlozi, osobito metionin i glicin, stabiliziraju aktivnost mitohondrija kvasca tijekom proizvodnje pića sake. Pomoću mutanta atg32△, koji ima narušenu aktivnost mitohondrija, istražili smo aminokiseline koje povećavaju aktivnost mitohondrija kvasca tijekom vrenja. Identificirali smo metionin i glicin kao aminokiseline koje bi mogle povećati aktivnost mitohondrija kvasca tijekom proizvodnje pića sake. Da bismo to potvrdili, izmjerili smo količinu reaktivnih oblika kisika u kvascu nakon vrenja u podlozi s metioninom i glicinom. Kvasac koji je fermentirao u podlozi s metioninom i glicinom zadržao je relativno veliku količinu reaktivnih oblika kisika u usporedbi s kvascem koji je fermentirao u podlozi bez dodatka aminokiselina. Osim toga, stanice koje su fermentirale u podlozi s dodatkom metionina imale su različit metabolom od stanica koje su fermentirale u podlozi bez dodatka aminokiseline. Rezultati pokazuju da određene aminokiseline, poput metionina i glicina, stabiliziraju aktivnost mitohondrija kvasca tijekom proizvodnje pića sake i na taj način upravljaju aktivnošću kvasca.Addition of amino acids to fermentation media affects the growth and brewing profiles of yeast. In addition, retaining mitochondrial activity during fermentation is critical for the fermentation profiles of brewer’s yeasts. However, a concrete mechanism linking amino acids in fermentation media with mitochondrial activity during fermentation of brewer’s yeasts is yet unknown. Here, we report that amino acids in fermentation media, especially methionine (Met) and glycine (Gly), stabilize mitochondrial activity during fermentation of sake yeast. By utilizing atg32Δ mutant sake yeast, which shows deteriorated mitochondrial activity, we screened candidate amino acids that strengthened the mitochondrial activity of sake yeast during fermentation. We identified Met and Gly as candidate amino acids that fortify mitochondrial activity in sake yeast during fermentation. To confirm this biochemically, we measured reactive oxygen species (ROS) levels in sake yeast fermented with Met and Gly. Yeast cells supplemented with Met and Gly retained high ROS levels relative to the non-supplemented sake yeast. Moreover, Met-supplemented cells showed a metabolome distinct from that of non-supplemented cells. These results indicate that specific amino acids such as Met and Gly stabilize the mitochondrial activity of sake yeast during fermentation and thus manipulate brewing profiles of yeast

Probiotic Characteristics of Pediococcus pentosaceus and Apilactobacillus kunkeei Strains: The lactic Acid Bacteria Isolated from Bangladeshi Natural Honey

Background and Objective: Lactic acid bacteria are known for their strong probiotic effects on the hosts. The probiotic characterization of lactic acid bacteria from Bangladeshi natural honey is limited. The objectives of this study included isolation and assessment of the probiotic and safety characteristics of lactic acid bacteria in Bangladeshi honey. Materials and Methods: Spread and streak plate techniques were used for the bacterial isolation and purification. Isolates were identified using 16S rRNA gene sequence analysis. Agar well diffusion and poisoned food methods were used for antibacterial and antifungal assessments, respectively. Antioxidant activity was carried out based on the microbial free-radical scavenging ability. Microbial autoaggregation, coaggregation and adhesion were assessed using cell sedimentation assay. Blood-agar was used in the hemolytic assay. Antibiotic susceptibility assay was carried out using disc diffusion method. Results and Conclusion: From a total of 25 strains isolated from honey, ten Gram-positive, catalase-negative non-spore-forming isolates were selected and used in agar well diffusion assay. Three of the isolates showed prominent antimicrobial effects with large inhibition zones against all the pathogenic strains, including Bacillus cereus, Staphylococcus aureus, Vibrio cholerae, Salmonella typhi and Candida albicans. Extensive characterization of these isolates was carried out, which revealed their growth and biochemical characteristics and carbohydrate fermentation abilities. Moreover, 16S rRNA gene sequence analysis suggested that the isolates belonged to Pediococcus pentosaceus (two strains) and Apilactobacillus kunkeei. Their tolerance to simulated gastric conditions was assessed in vitro wherein the isolates showed significant survival in low pH, bile salts and phenol. They showed good adhesion ability to ethyl acetate, chloroform and xylene as well as high autoaggregation and coaggregation characteristics. Moreover, free-radical scavenging activity of the isolates suggested the presence of considerable antioxidant effects. In safety assessment, the isolates did not show hemolytic activities and were resistant to several antibiotics. Therefore, these results indicate that honey can be an important source of beneficial lactic acid bacteria species providing several probiotic advantages. Conflict of interest: The authors declare no conflict of interes

Determination of pond water quality for aquaculture and ecosystem management

Fish is the main source of animal protein for the common people of Bangladesh. About 37% of the inland fishes are obtained from the closed water fish culture where ponds play vital roles in the production system. The present study was carried out to determine the water quality (physico-chemical and biological factors) of five uncultivated or under cultivated ponds in the Chittagong University campus, Bangladesh, for aquaculture and ecosystem management. Temperature, pH, EC, BOD, COD, TSS, turbidity, NO2-, PO4 -, free CO2, CO3 -, HCO3-, Cl-, total viable bacterial count and total coliform were determined. Isolation and identification of Escherichia coli and Salmonella sp. from the water samples were performed to investigate the antibiotic sensitivity. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against ciprofloxacin was also investigated. The findings reveal that there was no significant difference in temperature (19°C to 20°C), pH (6.7 to 7.4), electrical conductivity and Cl- values in the water among the ponds and that was within the range of the requirements for the fish cultivation. Both turbidity and total dissolved solids was highest in the uncultivated botanical garden pond 2 (BGP2). BOD, COD, NO2- , PO 4-2, HCO3-, and free CO2 concentration was beyond the permissible limits for aquaculture. Total viable count and total coliform ranged from 1.3 × 10 4 to 6.6 × 10 5 cfu ml-1 and from 0.0205×10 2 to 1.10×10 2 ml-1 respectively, among the ponds where both these parameters were highest in the naturally polluted BGP2. Most of the isolated E. coli and Salmonella sp. were sensitive but few showed resistance against the antibiotics, especially in BGP1, where fishes were cultivated commercially

Glycosylceramide modifies the flavor and metabolic characteristics of sake yeast

In the manufacture of sake, Japanese traditional rice wine, sake yeast is fermented with koji, which is steamed rice fermented with the non-pathogenic fungus Aspergillus oryzae. During fermentation, sake yeast requires lipids, such as unsaturated fatty acids and sterols, in addition to substances provided by koji enzymes for fermentation. However, the role of sphingolipids on the brewing characteristics of sake yeast has not been studied. In this study, we revealed that glycosylceramide, one of the sphingolipids abundant in koji, affects yeast fermentation. The addition of soy, A. oryzae, and Grifola frondosa glycosylceramide conferred a similar effect on the flavor profiles of sake yeast. In particular, the addition of A. oryzae and G. frondosa glycosylceramide were very similar in terms of the decreases in ethyl caprylate and ethyl 9-decenoate. The addition of soy glycosylceramide induced metabolic changes to sake yeast such as a decrease in glucose, increases in ethanol and glycerol and changes in several amino acids and organic acids concentrations. Tricarboxylic acid (TCA) cycle, pyruvate metabolism, starch and sucrose metabolism, and glycerolipid metabolism were overrepresented in the cultures incubated with sake yeast and soy glycosylceramide. This is the first study of the effect of glycosylceramide on the flavor and metabolic profile of sake yeast

Convolutional Neural Network Modeling for Eye Disease Recognition

The eye is an important sensing organ of the human body, as it reacts to light and allows vision of humans. Many Bangladeshi people become nearsighted when it comes to the awareness of vision loss due to eye disease. Many Bangladeshis people are more concerned about losing their money than getting nearsighted or blind, due to a combination of poverty and illiteracy. With this view, this paper proposes an osteopathic expert system that can deal with an image of the eye and recognize the disease. Here, we have focused on the three most common eye diseases in Bangladesh, namely cataract, chalazion, and squint. We have modeled six convolutional neural networks (CNN’s), namely VGG16, VGG19, MobileNet, Xception, InceptionV3, and DenseNet121 to recognize the diseases. We have reached the best configuration of each of these CNN models after adequate investigation. After performing satisfactory experimentation, we have found that the MobileNet model gives the best performance based on accuracy, precision, recall, and F1-score. At last, we have compared our findings with the recently reported relevant works to show their efficacy

Identification and detoxification of glycolaldehyde, an unattended bioethanol fermentation inhibitor

<p>Although there have been approximately 60 chemical compounds identified as potent fermentation inhibitors in lignocellulose hydrolysate, our research group recently discovered glycolaldehyde as a key fermentation inhibitor during second generation biofuel production. Accordingly, we have developed a yeast <i>S. cerevisiae</i> strain exhibiting tolerance to glycolaldehyde. During this glycolaldehyde study, we established novel approaches for rational engineering of inhibitor-tolerant <i>S. cerevisiae</i> strains, including engineering redox cofactors and engineering the SUMOylation pathway. These new technical dimensions provide a novel platform for engineering <i>S. cerevisiae</i> strains to overcome one of the key barriers for industrialization of lignocellulosic ethanol production. As such, this review discusses novel biochemical insight of glycolaldehyde in the context of the biofuel industry.</p

Probiotic Potentiality of Lactobacillus coryniformis subsp. Torquens MTi1 and Lactobacillus coryniformis MTi2 Isolated from Intestine of Nile Tilapia: An In vitro Evaluation

Inefficiency of antibiotics because of emerging resistance, to reduce use of chemical preservatives and to alleviate other gastrointestinal or urogenital disorders- using probiotics get prioritized in recent times. We investigated probiotic potentiality of L. coryniformis subsp. torquens MTi1 and L. coryniformis MTi2 isolated from Nile Tilapia. A set of in vitro probiotic parameters (antibacterial activity, temperature sensitivity, pH, bile salt, NaCl tolerance, antibiotics resistance) were evaluated by performing disc diffusion, agar well diffusion methods and several other microbiological tests. Both isolates demonstrated antibacterial activity against Escherichia coli, Salmonella Typhii, Bacillus subtilis and Pseudomonas aeruginosa whereas L. coryniformis MTi1 also active against Staphylococcus aureus. They could grow at wide range of temperatures(27-45°C) and pH (2-9); had tolerance to 0.5-2% bile salt and 1-7% NaCl; ferment lactose. L. coryniformis subsp. torquens MTi1 was not killed by Cefixime(5µg) whereas L. coryniformis MTi2 neither killed by Cefixime(5µg) nor Streptomycin(10µg) in antibiotic susceptibility testing. Best antibacterial production of isolates found at 37°C, pH 2 and after 72 hours of incubation. We observed approximately 42% and 40% more antibacterial production from L. coryniformis subsp. torquens MTi1 and L. coryniformis MTi2 respectively after 72 hours of incubation instead of 24 hours. L. coryniformis MTi2 could produce bacteriocin or bacteriocin like substances active against E. coli (15mm) and B. subtilis (14mm). The study concludes based on empirical observations that, the isolates have potentiality to be efficient probiotic which will eventually contribute to promote public health

Chromosomal aneuploidy improves the brewing characteristics of sake yeast

The effect of chromosomal aneuploidy on the brewing characteristics of brewery yeasts has not been studied. Here we report that chromosomal aneuploidy in sake brewery yeast (Saccharomyces cerevisiae) leads to the development of favorable brewing characteristics. We found that pyruvate-underproducing sake yeast, which produces less off-flavor diacetyl, is aneuploid and trisomic for chromosomes XI and XIV. To confirm that this phenotype is due to aneuploidy, we obtained 45 haploids with various chromosomal additions and investigated their brewing profiles. A greater number of chromosomes correlated with a decrease in pyruvate production. Especially, sake yeast haploids with extra chromosomes in addition to chromosome XI produced less pyruvate than euploids. Mitochondrion-related metabolites and intracellular oxygen species in chromosome XI aneuploids were higher than those in euploids, and this effect was canceled in their "petite" strains, suggesting that an increase in chromosomes upregulated mitochondrial activity and decreased pyruvate levels. These findings suggested that an increase in chromosome number, including chromosome XI, in sake yeast haploids leads to pyruvate underproduction through the augmentation of mitochondrial activity. This is the first report proposing that aneuploidy in brewery yeasts improves their brewing profile

Genomic analysis and in vivo efficacy of Pediococcus acidilactici as a potential probiotic to prevent hyperglycemia, hypercholesterolemia and gastrointestinal infections

Abstract Lactic acid bacteria are the well acknowledged probiotics that can cure a variety of diseases. In this study, we observed the in vivo potentials of Pediococcus to treat hyperglycemia, hypercholesterolemia and gastrointestinal infections. A total of 77 Lactobacillus were isolated from the milk of 10 cows and 10 goats, four of those strains inhibited both carbohydrates-hydrolyzing enzymes, α-glucosidase, and α-amylase. They all showed antagonistic effects on pathogenic E. coli and S. Typhimurium which were confirmed by performing pathogen challenge test and visualizing on Electron microscopy. 16S rRNA gene sequence identified that all four strains belong to Pediococcus genus which were further distinguished as Pediococcus acidilactici by pheS gene sequence. Whole genome sequence analysis revealed their non-pathogenic properties for human and the presence of probiotic genes responsible for stress resistance, immunomodulation, adhesion, metal and drug resistance. In vivo trial with diabetes-induced mice ascertained that all Pediococcus acidilactici had significant potentials to reduce elevated glucose and low-density lipoprotein level in blood. Interestingly, two out of four strains were significantly more effective (p < 0.0001 each) than metformin in reducing the blood glucose level. This in vivo study demonstrated that Pediococcus acidilactici might be a promising probiotic to prevent hyperglycemia, hypercholesterolemia and gastrointestinal infections