Biology subjects

Masuo, S.

Publications and source records attributed to Masuo, S..

3 recordsLinked to original sources

bioRxiv2025

The increase in cell volume and nuclear number of the koji-fungus Aspergillus oryzae contributes to its high enzyme productivity

While the ratio of nuclei to cell volume is well regulated, it remains largely unexplored in multinucleate organisms. The koji-fungus Aspergillus oryzae, traditionally used in Japanese brewing and fermentation for over a thousand years, is now widely utilized in modern biotechnology as a host for enzyme production. We discovered that, over time in culture, hyphae become thicker, resulting in a tenfold increase in cell volume, and the number of nuclei in hyphal cells also increases tenfold, exceeding 200. The increase in cell volume and nuclear number is unique among the investigated Aspergillus species and correlates with its high enzyme production capabilities. Since nuclear number and cell volume are correlated, both must increase simultaneously for either to expand. Our analyses identified genetic factors and nutritional environmental signals involved in each of these increases. Increases in nuclear number and cell volume were also observed in other fungi bred for industrial use. This study not only deepens our understanding of the evolutionary processes that promote high enzyme productivity through fungal breeding, but also provides insights into the molecular mechanisms regulating cell volume and nuclear number in multinucleate organisms.

microbiology↗

bioRxiv2023

Machine learning-assisted medium optimization revealed the discriminated strategies for improved production of the foreign and native metabolites

The medium composition was crucial for achieving the best performance of synthetic construction. What and how medium components determined the production of the synthetic construction remained poorly investigated. To address the questions, a comparative survey with two genetically engineered Escherichia coli strains was performed. As a case study, the strains carried the synthetic pathways for producing the aromatic compounds of 4APhe or Tyr, which were common in the upstream but differentiated in the downstream metabolism. Bacterial growth and compound production were examined in hundreds of medium combinations that comprised 48 pure chemicals. The resultant data sets linking the medium composition to bacterial growth and production were subjected to machine learning for improved production. Intriguingly, the primary medium components determining the production of 4PheA and Tyr were differentiated, which were the initial resource (glucose) of the synthetic pathway and the inducer (IPTG) of the synthetic construction, respectively. Fine-tuning of the primary component significantly increased the yields of 4APhe and Tyr, indicating that a single component could be crucial for the performance of synthetic construction. Transcriptome analysis observed the local and global changes in gene expression for improved production of 4APhe and Tyr, respectively, revealing divergent metabolic strategies for producing the foreign and native metabolites. The study demonstrated that ML-assisted medium optimization could provide a novel point of view on how to make the synthetic construction meet the original design.

systems biology↗

bioRxiv2020

Coronatine contributes Pseudomonas cannabina pv. alisalensis virulence by overcoming both stomatal and apoplastic defenses in dicot and monocot plants

P. cannabina pv. alisalensis (Pcal) is a causative agent of bacterial blight of crucifer including cabbage, radish, and broccoli. Importantly, Pcal can infect not only a wide range of Brassicaceae, but also green manure crops such as oat. However, Pcal virulence mechanisms have not been investigated and are not fully understood. We focused on coronatine (COR) function, which is one of the well-known P. syringae pv. tomato DC3000 virulence factors, in Pcal infection processes on both dicot and monocot plants. Cabbage and oat plants dip-inoculated with a Pcal KB211 COR mutant ({Delta}cmaA) exhibited reduced virulence compared to Pcal WT. Moreover, {Delta}cmaA failed to reopen stomata on both cabbage and oat, suggesting that COR facilitates Pcal entry through stomata into both plants. Furthermore, cabbage and oat plants syringe-infiltrated with {Delta}cmaA also showed reduced virulence, suggesting that COR is involved in overcoming not only stomatal-based defense, but also apoplastic defense. Indeed, defense related genes, including PR1 and PR2, were highly expressed in plants inoculated with {Delta}cmaA compared to Pcal WT, indicating that COR suppresses defense-related genes of both cabbage and oat. Additionally, SA accumulation increases after {Delta}cmaA inoculation compared to Pcal WT. Taken together, COR contributes to cause disease by suppressing stomatal-based defense and apoplastic defense in both dicot and monocot plants. This is the first study to investigate COR functions in the interaction of Pcal and different host plants (dicot and monocot plants) using genetically and biochemically defined COR deletion mutants. Author summaryDisease outbreaks caused by new Pseudomonas syringae isolates are problems worldwide. P. cannabina pv. alisalensis (Pcal) causes bacterial blight on a wide range of cruciferous plants and bacterial brown spot on oat plants. Although P. syringae deploys a variety of virulence factors, Pcal virulence factors have not been investigated. We focused on coronatine (COR) function, which is one of the well-known P. syringae virulence factors. COR is a non-host-specific phytotoxin and contributes to P. syringae growth and lesion formation or expansion in several host plants. COR function has been mainly studied in the model pathogen P. syringae pv. tomato DC3000 and model the plant Arabidopsis thaliana. Thus, COR roles in Pcal infection especially on monocot plants have not been well studied. Therefore, we investigated COR role in Pcal interaction with both dicot and monocot plants. Here, we revealed that COR functions as a multifunctional suppressor to manage Pcal virulence on both plants.

plant biology↗