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At least 19 recordsLinked to original sources
PubMed2026

Bioengineering and physicochemical optimization of ergothioneine production by Aspergillus oryzae.

Ergothioneine (EGT) is a bioactive, rare variant of histidine with many applications in the medical, pharmaceutical, and food fields. Therefore, we aimed to investigate in this study the impact of genomic and physicochemical factors on EGT production by the industrial filamentous fungus Aspergillus oryzae. Firstly, to facilitate efficient EGT production, we analyzed the subcellular localization of the three EGT biosynthetic enzymes present in A. oryzae. During screening for the most potent producer of EGT among bioengineered transformants, the strain EgtACO overexpressing both AoegtA and AoegtC showed promising EGT production in DPY medium. Five days of incubation was the optimum period, and CZYP medium was the optimum medium for EGT production. Co-cultivation with the nisin Z-producing Lactococcus lactis JCM 7638 yielded EGT production equivalent to that of the EgtACO strain alone. Having broad-spectrum antimicrobial activity without suppressing growth of the EgtACO strain suggested that bacteriocin may help reduce the risk of contamination during long-term cultivation. Moreover, supplementing the production medium with L-methionine or zinc sulfate improved EGT production (1468.5 or 1565 mg/L, respectively). Furthermore, repeated inoculation of the producer strain EgtACO and incubation in blue light were the optimum conditions for EGT production (1895 mg/L). Finally, we achieved cost-effective EGT production using A. oryzae strain EgtACO under the optimal culture conditions using agricultural wastes: potato peel and sweet potato peel (293 and 308 mg/L, respectively).

Aspergillus oryzae↗
PubMed2026

Effects of multistrain probiotic supplementation on hepatic function and anthropometric parameters in patients with metabolic dysfunction-associated steatotic liver disease: a double-blind, randomized controlled trial.

BACKGROUND: Metabolic dysfunction-associated steatotic liver disease (MASLD) is increasingly prevalent on a global scale. The gut microbiota is integral to its pathogenesis, prompting extensive research into microbiota modulation as a potential adjunctive therapeutic strategy. AIM: The study aimed to evaluate the effect of multistrain probiotics supplementation on hepatic function in patients with MASLD in a double-blind, randomized, controlled trial. The primary outcomes were changes in Fibrosis-4 index (FIB-4) and fatty liver index (FLI). Secondary outcomes included changes in anthropometric parameters, selected biochemical markers, and other liver-related indices. METHODS: A total of 64 patients with MASLD were randomly assigned to two groups receiving either placebo (C) or a probiotic mixture (PRO) containing the following bacterial strains: 50% Lactococcus lactis Rosell-1058, 25% Lacticaseibacillus casei Rosell-215, 12.5% Lactobacillus helveticus Rosell-52, 12.5% Bifidobacterium bifidum Rosell-71 for 12 wk. RESULTS: Significant group &#xd7; time interactions were observed for FIB-4 (Q = 0.007), with reduction in the PRO group and increase in the C group (-0.05 vs. 0.10; P = 0.002). No significant interaction was found for FLI (Q = 0.942). Significant group &#xd7; time interactions were also observed for aspartate aminotransferase (-2.87 vs. 1.87 U/L; Q = 0.003) and APRI (-0.03 vs. 0.02; Q = 0.001), favoring the PRO group (P < 0.001 for both). No significant changes were observed in anthropometric parameters, glucose levels, or lipid profile. CONCLUSIONS: In patients with MASLD, the 12-wk probiotic supplementation had a modest but statistically significant effect on FIB-4, aspartate aminotransferase, and APRI, with no significant effect on FLI or anthropometric and metabolic parameters. These findings suggest that this probiotic formulation may have potential benefits for liver function in MASLD. However, long-term studies incorporating imaging-based and histological endpoints are required to determine the clinical significance of these findings.

Humans↗
PubMed2025

Consumption of traditional Sardinian fermented milk promotes changes in the rat gut microbiota composition and functions.

BACKGROUND: Fermented milk products are part of the staple diet for many Mediterranean populations. Most of these traditional foods are enriched with lactobacilli and other lactic acid bacteria, as well as with metabolites resulting from lactose fermentation. Currently, there is very little scientific knowledge on how dietary supplementation with fermented milk affects the composition of the gut microbiota and its metabolic activities. RESULTS: We integrated 16&#xa0;S rRNA gene-based taxonomic profiling with metaproteomics-based functional analysis to investigate gut microbiota changes in rats exposed to an 8-week dietary supplementation with casu axedu, a traditional fermented milk produced within rural communities in Sardinia (Italy). Several microbial taxa showed a significantly increased abundance at the end of the dietary treatment, including Phascolarctobacterium, Prevotella, Blautia glucerasea, and Lactococcus lactis, while Bacteroides dorei and Helicobacter rodentium were decreased compared to the control rats. Metaproteomic analysis highlighted a striking reshaping of the Prevotella proteome in agreement with its blooming in casu axedu-fed animals, suggesting an increase of the glycolytic activity through the Embden-Meyerhof-Parnas pathway over the Entner-Doudoroff pathway. Moreover, an increased production of enzymes involved in succinate biosynthesis was observed, which in turn significantly boosted the abundance of Phascolarctobacterium and its production of propionate. Fermented milk consumption also promoted microbial synthesis of branched chain essential amino acids L-valine and L-leucine. Finally, metaproteomic data indicated a reduction of bacterial virulence factors and host inflammatory markers, suggesting that the consumption of casu axedu can have beneficial effects on the gut mucosa health. CONCLUSIONS: Our integrated multi-omics approach reveals that dietary supplementation with the traditional Sardinian fermented milk, casu axedu, induces significant shifts in the rat gut microbiota composition and function, characterized by the enrichment of beneficial taxa and metabolic pathways associated with improved gut health and reduced inflammation.

Animals↗
PubMed2026

Host immunogenetic variation and gut microbiome functionality in a wild vertebrate population.

BACKGROUND: The gut microbiome (GM) -important for host health and survival- is partially shaped by host immunogenetics. However, to date, no study has investigated the influence of host Major Histocompatibility Complex (MHC) genes on gut microbiome functionality in a wild population. Here we use a natural population of the Seychelles warbler (Acrocephalus sechellensis) to assess the effects of MHC genes on GM taxonomy and functionality using shotgun metagenomics. RESULTS: Our results show that taxonomic GM composition was associated with MHC-II diversity and the presence of one specific MHC-I allele (Ase-ua 7). Specifically, MHC-II diversity was associated with decreased Lactococcus lactis and increased Staphylococcus lloydii abundance, while Ase-ua 7 was linked to reduced Enterococcus casselifavus and Gordonia sp OPL2 but increased Escherichia coli and Vulcaniibacterium thermophilum. These taxonomic changes may reflect differences in MHC-mediated microbial recognition. In contrast, functional GM composition was significantly associated with increasing individual MHC-I diversity but not MHC-II diversity. In particular, increasing MHC-I diversity was associated with an increased prevalence of microbial defence genes but a reduced prevalence of microbial metabolism genes. Analysis also revealed that functional GM networks were more fragmented in high compared to low MHC-I diversity hosts. CONCLUSION: These results suggest that MHC variation (particularly at MHC-I) plays an important role in shaping both the taxonomy and function of the GM in wild vertebrates. In the Seychelles warbler, this results in trade-offs whereby there is an increase in microbial defence and a reduction in GM metabolic potential in individuals with higher MHC-I diversity. Thus, this work sheds light on the possible costs and benefits of maintaining a healthy microbiome, which is essential for understanding how the GM and immune system co-evolve. Video Abstract.

Animals↗
PubMed1976

Isolation and examination of transducing bacteriophage particles from Streptococcus lactis C2.

Two defective transducing bacteriophages induced by exposure of Streptococcus lactis C2 to ultraviolet irradiation have been isolated and characterized. These temperate phages designated c2t1 and c2t2 were isolated by cesium chloride equilibrium density gradient centrifugation of phage preparations concentrated by polyethylene glycol precipitation. The equilibrium gradient contained two visually apparent phage bands positioned at densities of 1.487 and 1.463 g cm-3 respective for c2t1 and c2t2. Particle morphology and phenol extracted phage deoxyribonucleic acid were examined by electron microscopy for each phage. Head diameter, deoxyribonucleic acid length, and molecular weight for c2t1 were 60 nm, 10.9 mum, and 22.6 x 10(6) daltons, respectively. Phage c2t2 had a head diameter of 70nm, a deoxribonucleic acid length of 11.4 mum, and a molecular weight of 23.8 x 10(6) daltons. Comparing head diameter and phage deoxyribonucleic acid length suggests that the variation in c2t1 and c2t2 density was due to difference in head size. Phage c2t2 exhibited high frequency transduction of lactose metabolism based on preparations equilibrated by adjustment of optical density at 260 nm. Maltose and proteinase markers also were transduced by both phages. The transducing phage was defective, requiring a helper for the formation of transducing particles but not for the transduction process. Superinfection immunity was not conferred on post-infecting phage. The results demonstrated transduction by two nonidentical phage particles lysogenic for S. lactis C2.

Bacteriophages↗
PubMed1978

In vivo regulation of glycolysis and characterization of sugar: phosphotransferase systems in Streptococcus lactis.

Two novel procedures have been used to regulate, in vivo, the formation of phosphoenolpyruvate (PEP) from glycolysis in Streptococcus lactis ML3. In the first procedure, glucose metabolism was specifically inhibited by p-chloromercuribenzoate. Autoradiographic and enzymatic analyses showed that the cells contained glucose 6-phosphate, fructose 6-phosphate, fructose-1,6-diphosphate, and triose phosphates. Dithiothreitol reversed the p-chloromercuribenzoate inhibition, and these intermediates were rapidly and quantitatively transformed into 3- and 2-phosphoglycerates plus PEP. The three intermediates were not further metabolized and constituted the intracellular PEP potential. The second procedure simply involved starvation of the organisms. The starved cells were devoid of glucose 6-phosphate, fructose 6-phosphate, fructose- 1,6-diphosphate, and triose phosphates but contained high levels of 3- and 2-phosphoglycerates and PEP (ca. 40 mM in total). The capacity to regulate PEP formation in vivo permitted the characterization of glucose and lactose phosphotransferase systems in physiologically intact cells. Evidence has been obtained for "feed forward" activation of pyruvate kinase in vivo by phosphorylated intermediates formed before the glyceraldehyde-3-phosphate dehydrogenase reaction in the glycolytic sequence. The data suggest that pyruvate kinase (an allosteric enzyme) plays a key role in the regulation of glycolysis and phosphotransferase system functions in S. lactis ML3.

Biological Transport↗
PubMedDate not supplied

[Influence of pH on nisin production by Streptococcus lactis cultures].

The pH effect on the nisine biosynthesis during the cultivation of Streptococcus lactis was studied at pH 5,8 6,7 and 7,2. The pH maintenance at the specified level did not stimulate the growth of Str. lactis, did not increase the total yield of nisine and did not produce a significant effect on the level or cellular nisine. This indicates an important physiological difference between the culture-nisine producer described by Hirsh and our culture Str. lactis, str. Moscow University.

Hydrogen-Ion Concentration↗
PubMed1978

Peptide utilization by group N streptococci.

The rate of glycylleucine uptake by Group N streptococci varied widely. One strain of Streptococcus cremoris did not transport the dipeptide or utilize tripeptides. In peptide-utilizing strains, amino acid, dipeptide and tripeptide transport were distinct, although dipeptides inhibited tripeptide utilization. Specificity determinants for peptide transport and utilization were similar to those reported in Gram-negative bacteria. Peptide utilization in S. lactis was not completely dependent on the transport of intact peptides.

Amino Acids↗
PubMedDate not supplied

[Effect of KH2PO4 on Streptococcus lactis growth and nisin synthesis when the medium is kept at a constant pH].

When the pH of the medium was maintained at the level of 6.6--6.8 and the content of KH2PO4 in it was decreased, the biosynthetic activity of Streptococcus lactis, strain MGU, became lower. The culture assimilated low quantities of phosphorus from KH2PO4 at a high concentration of this salt in the medium; presumably, the culture required large quantities of potassium ions. If the pH of the medium is maintained at a constant value, the fermentation can be stopped 21 hr after the beginning of cultivation of Str. lactis, strain MGU.

Hydrogen-Ion Concentration↗
PubMed1979

Characterization of groups N and D streptococci isolated from rumen fluids.

Twelve strains of streptococci of serological groups N and D were isolated from rumen fluids of nine cows on four rations although both groups were not isolated from the same animal. The twelve were representative of a larger number of streptococci isolated by enrichment in milk. Generally, the physiological characteristics of the isolates indicated members of the lactic or enterococcus groups; however, several were atypical in one or more of the tolerance tests. Physiologically typical Streptococcus lactis but not S. cremoris, were isolated.

Animals↗
PubMed1978

[Nisin formation by immobilized cells of the lactic acid bacterium, Streptococcus lactis].

The problem of microbial cell immobilization at present attracts the ever increasing attention of the scientists, since such organisms may be the source of various enzymes. Production of nizin by the immobilized cells of Str. lactis was studied. It was found that the cells of Str. lactis incorporated into polyacrylamide gel produced nizit on definite media. Still, the amount of the antibiotic was 2-3 times lower than in case of using free cells. The effect of a number of factors on the process of immobilization was studied and the influence of some factors, such as temperature, pH, aeration on nizin synthesis by the immobilized cells of the streptococcus was elucidated. Optimal conditions for nizin biosynthesis by the immobilized cells of Str. lactis were developed.

Acrylamides↗