The mechanism of anthracene degradation by tryptophan -2,3-dioxygenase (T23D) in Comamonas testosteroni.

It is well known that anthracene is a persistent organic pollutant. Among the four natural polycyclic aromatic hydrocarbons (PAHs) degrading strains, Comamonas testosterone (CT1) was selected as the strain with the highest degradation efficiency. In the present study, prokaryotic transcriptome analysis of CT1 revealed an increase in a gene that encodes tryptophane-2,3-dioxygenase (T23D) in the anthracene and erythromycin groups compared to CK. Compared to the wild-type CT1 strain, anthracene degradation by the CtT23D knockout mutant (CT-M1) was significantly reduced. Compared to Escherichia coli (DH5α), CtT23D transformed DH5α (EC-M1) had a higher degradation efficiency for anthracene. The recombinant protein rT23D oxidized tryptophan at pH 7.0 and 37 °C with an enzyme activity of 2.42 ± 0.06 µmol min-1·mg-1 protein. In addition, gas chromatography-mass (GC-MS) analysis of anthracene degradation by EC-M1 and the purified rT23D revealed that 2-methyl-1-benzofuran-3-carbaldehyde is an anthracene metabolite, suggesting that it is a new pathway.

ATL Protein Family: Novel Regulators in Plant Response to Environmental Stresses.

Plants actively develop intricate regulatory mechanisms to counteract the harmful effects of environmental stresses. The ubiquitin-proteasome pathway, a crucial mechanism, employs E3 ligases (E3s) to facilitate the conjugation of ubiquitin to specific target substrates, effectively marking them for proteolytic degradation. E3s play critical roles in many biological processes, including phytohormonal signaling and adaptation to environmental stresses. Arabidopsis Toxicosa en Levadura (ATL) proteins, belonging to a subfamily of RING-H2 E3s, actively modulate diverse physiological processes and plant responses to environmental stresses. Despite studies on the functions of certain ATL family members in rice and Arabidopsis, most ATLs still need more comprehensive study. This review presents an overview of the ubiquitin-proteasome system (UPS), specifically focusing on the pivotal role of E3s and associated enzymes in plant development and environmental adaptation. Our study seeks to unveil the active modulation of plant responses to environmental stresses by E3s and ATLs, emphasizing the significance of ATLs within this intricate process. By emphasizing the importance of studying the roles of E3s and ATLs, our review contributes to developing more resilient plant varieties and promoting sustainable agricultural practices while establishing a research roadmap for the future.

Regulatory Mechanism of the Constitutive Photomorphogenesis 9 Signalosome Complex in Response to Abiotic Stress in Plants.

The constitutive photomorphogenesis 9 (COP9) signalosome (CSN) is a highly conserved protein complex that regulates signaling pathways in plants under abiotic stress. We discuss the potential molecular mechanisms of CSN under abiotic stress, including oxidative stress with reactive oxygen species signaling, salt stress with jasmonic acid, gibberellic acid, and abscisic acid signaling, high-temperature stress with auxin signaling, and optical radiation with DNA damage and repair response. We conclude that CSN likely participates in affecting antioxidant biosynthesis and hormone signaling by targeting receptors, kinases, and transcription factors in response to abiotic stress, which potentially provides valuable information for engineering stress-tolerant crops.