Methionine gamma-lyase enzyme was isolated and purified from Mucor irregularis PQ344458 fungal isolates, that obtained from plant root, the isolates were identified through observation of their colony morphological features, implementation of PCR and DNA sequencing via sanger-chain termination approach, then data of DNA sequence alignment, phylogenetic tree, percent identity was generated. Through implementation of several stages that involved using of ion-exchange chromatography, gel-filtration chromatography, ammonium sulphate, enzyme isolation and purification stages were accomplished. The enzyme extract then, was analyzed for its protein content, specific activity and Impact of pH, temperature, inhibitors and activators on its kinetics. Additionally, MTT and DPPH radical scavenging assays were carried-out to reveal information about anti-cancer and anti-oxidant activities of methionine gamma-lyase enzyme. MTT assay results of %viable cells were 15% for HeLa cells and 6.6% for U937 cells at maximum concentration of the enzyme extract. Moreover, DPPH scavenging activity results were 82% at maximum concentration.

Water is indispensable to life, yet some cyanobacteria inhabit hyper-arid deserts and withstand complete desiccation. However, the molecular mechanisms enabling such acclimation remain incompletely understood. In Anabaena sp. strain PCC 7120, the gene avaKa, which encodes a protein of unknown function, has been shown to be required for desiccation tolerance. Here, we characterized the avaKa disruptant DRavaKa under dehydration-related stress conditions. DRavaKa displayed hypersensitivity to EDTA, and transcripts of iron-deficiency-inducible genes (isiA1, isiB, furA, and sufB) were elevated even in the absence of EDTA. Whole-cell absorption spectra of DRavaKa revealed a blue shift of the chlorophyll absorption peak, a characteristic feature of iron-deficient cyanobacteria. In addition, the oxidative-stress-inducible gene trxA2 was likewise upregulated. These results indicate that AvaKa contributes to iron homeostasis and that iron deficiency-induced oxidative stress likely underlies the dehydration sensitivity of DRavaKa.

The extracellular export of target chemicals is essential for achieving the target productivity of microbial cell factories (MCFs). We demonstrated that MscCG, a mechanosensitive channel responsible for glutamate export in glutamate-producing MCF of Corynebaterium glutamicum, can export various intracellular low-molecular-weight chemicals outside the cell. The mechanosensitive channels exporter improved L-Lys productivity and conferred substantial 5'-IMP fermentative production ability to the Escherichia coli MCF, which lacks inherent 5'-IMP exporters, indicating that mechanosensitive channels, which are low selective, functioned effectively as MCF exporters. We also demonstrated the effectiveness of a gain-of-function (GOF) mutation of mechanosensitive channels as MCF exporters; however, the essential mechanism underlying this GOF mutation remains unknown. Therefore, we performed molecular dynamics simulations to identify this mechanism at the atomic level. Consequently, we partially elucidated the underlying mechanism of G46D-induced GOF in MscL, which was effective as a 5'-IMP exporter. Specifically, the kink at A38 in the inner transmembrane helix of MscL forming its pore can affect GOF behavior. Based on these results, we conclude that mechanosensitive channels have potential as innovative and versatile exporters of MCFs, capable of enhancing the production efficiency of target chemicals and enabling their production in the absence of natural exporters.

Actinoplanes missouriensis grows by forming branched substrate mycelia and produces terminal sporangia. Each sporangium contains a few hundred spores, which swim as zoospores after being released from sporangia. Previously, we disrupted 22 putative acyltransferase genes and examined their involvement in morphological differentiation. Here, we described the characterization of one of them, a putative 1-acyl-2-hydroxy-sn-glycerol-3-phosphate acyltransferase (AGPAT) encoded by plsC (AMIS_11360). The plsC null (∆plsC) mutant exhibited a conditional growth defect in a nutrient-poor medium. No differences were observed between the wild-type and ∆plsC strains in sporangium formation, spore release, or zoospore motility. We confirmed the AGPAT activity of PlsC; the recombinant polyhistidine-tagged PlsC protein transferred the acyl group from palmitoyl-coenzyme A to 1-palmitoyl-2-hydroxy-sn-glycero-3-phosphate, resulting in the production of 1,2-dipalmitoyl-sn-glycero-3-phosphate.

Acetic acid bacteria, including the genera Acetobacter and Komagataeibacter, utilize phosphatidylcholine (PC) as a major membrane component, which plays an important role in their membrane physiology. However, the significance of PC abundance within the membrane remains speculative. Here, we constructed a mutant strain of A. pasteurianus through genome modification, enabling choline-dependent PC production. This mutant exhibited different dependencies on PC levels in response to strong and weak acid stress, requiring higher PC levels under strong acid stress but lower levels under weak acid stress. These findings provide new insights into the membrane-based mechanisms of acid-stress response in A. pasteurianus.

At the 2025 Osaka/Kansai Expo, a bacterial-bioluminescence-based lighting system, called BIOLIGHT, was exhibited. It consists of 80 liters of liquid culture medium and produces enough brightness to illuminate a room. In this study, to make clear the relationship between the liquid culture thickness and the brightness using BIOLIGHT, the world's largest liquid culture aquarium of bioluminescent bacteria, we investigated the brightness of the bacterial liquid culture in relation to optical density (OD). The theoretical brightness of BIOLIGHT was calculated using the transmittance of the liquid culture at 475 nm (the peak luminescence wavelength) derived from the measured OD and was then compared with the brightness actually measured. The calculated (theoretical) brightness was lower than the measured one, suggesting that the light output of BIOLIGHT is influenced not only by cell-induced light shielding but also by another factor, presumably forward scattering. Additionally, depth-dependent brightness measurements showed that brightness became saturated at a liquid culture thickness greater than 7 cm. These findings will contribute to the design of future lighting solutions using bacterial bioluminescence.

Superoxide dismutases (SODs) play crucial roles in cellular oxidative stress defense. In Aspergillus nidulans, SodB is a mitochondria-localized SOD whose physiological function remains poorly understood. Here, we show that a ΔsodB mutant displays impaired growth on non-fermentable carbon sources including acetate, ethanol, threonine, and Tween 20/80, suggesting compromised mitochondrial function. Oxygen consumption assays using an extracellular oxygen consumption reagent revealed a ~50% reduction in respiratory activity in the ΔsodB strain compared to the wild type. When mitochondrial respiration was inhibited by Antimycin A or salicylhydroxamic acid, giant colony growth was equally suppressed across wild-type, ΔsodA, ΔsodB, and complemented strains. However, conidial production was significantly reduced in ΔsodB under Antimycin A treatment, and morphological abnormalities in conidiophore heads were observed under this condition. These results indicate that SodB is not only involved in mitochondrial respiration but also required for maintaining normal sporulation under mitochondrial stress conditions. This study provides new insights into the role of mitochondrial ROS defense systems in filamentous fungal development.

Lactic acid bacteria (LAB) are widely recognized for their health benefits and are commonly incorporated into functional foods. However, their survival and metabolic performance depend on the availability of appropriate substrates. This study evaluated the ability of LAB isolated from Dioscorea species to utilize starch from Dioscorea luzonensis, an endemic plant in the Philippines. Among the isolates tested, Limosilactobacillus fermentum PJG11 demonstrated the highest efficiency in converting D. luzonensis starch into glucose. This enhanced starch utilization can be explained by the upregulation of the α-amylase gene when the strain was cultured with its natural substrate, resulting in accelerated starch granule degradation. These findings underscore the importance of using natural, plant-derived substrates in the development of LAB-based functional foods to support optimal bacterial activity and improve carbohydrate breakdown for enhanced nutritional value.

Kusaya shows a high preservability due to the microorganism-derived antibiotics contained in kusaya gravy, which is important for kusaya manufacturing. However, the antimicrobial compounds and its producing bacteria, as well as the antimicrobial activity of the kusaya gravy itself, have remained unknown. In this study, we isolated antibiotic-producing bacteria of the genus Streptomyces from kusaya gravy from Hachijojima and found that they produced antibacterial substances against various fungi and bacteria. In addition, we demonstrated that kusaya gravy itself shows antimicrobial activity, which was consistent with that of the isolates. This is the first report to directly indicate that kusaya gravy contains microorganism-derived antibiotics, which are assumed to be produced by actinomycetes.

Gene expression controllers are useful tools for microbial production of recombinant proteins and valued bio-based chemicals. Despite its usefulness, they have rarely been applied to the practical industrial bioprocess, due to the lack of systems that meets the three requirements: low cost, safety, and tight control, to the inducer molecules. Previously, we have developed the high-spec gene induction system controlled by safe and cheap inducer choline. However, the system requires relatively high concentration (~100 mM) of choline to fully induce the gene under control. In this work, we attempted to drastically improve the sensitivity of this induction system to further reduce the induction costs. To this end, we devised a simple circuit which couples gene induction system with positive-feedback loop (P-loop) of choline importer protein BetT. After the tuning of translation level of BetT (strength of the P-loop) and deletion of endogenous betI (noise sources), highly active yet stringent control of gene expression was achieved using about 100 times less amount of inducer molecules. The choline induction system developed in this study has the lowest basal expression, the lowest choline needed to be activated, and the highest amplitude of induction as the highest available promoter such as those known as PT5 system. With this system, one can tightly control the expression level of genes of interest with negligible cost for inducer molecule, which has been the bottleneck for the application to the large-scale industrial processes.