AtaGenix June Research Highlights: Five Publications Spanning Archaea, Pest Control, Monkeypox Diagnostics, and Aquaculture

Archaea of the order Sulfolobales share a cell cycle architecture strikingly similar to that of eukaryotes, yet the transcriptional regulatory mechanisms governing their cell cycle have remained poorly understood. Using the thermoacidophilic archaeon Saccharolobus islandicus REY15A as a model, this study identified three ribbon-helix-helix (RHH) domain-containing transcription factors — aCcr1, aCcr2, and aCcr3 — and systematically characterized their roles in cell cycle control. All three function as transcriptional repressors that recognize similar promoter regulatory sequences, but with distinct temporal expression patterns: aCcr2 is constitutively expressed throughout the cell cycle, while aCcr1 and aCcr3 are periodically upregulated at the M/G1 and G1/S transitions, respectively. Mechanistically, the eukaryotic-like kinase aCcrK phosphorylates aCcr2 at Ser24, substantially weakening its DNA-binding affinity and thereby relieving repression of key cell cycle genes to open a window for mitotic entry; aCcr1 subsequently restores repression via its higher promoter-binding affinity, ensuring orderly cell cycle progression. Based on these findings, the authors propose a "phosphorylation-assisted checkpoint" model, arguing that the core logic of cell cycle regulation in Sulfolobales relies on timed repression and de-repression of key genes rather than active transcriptional activation — a mechanism that may represent a simplified evolutionary intermediate between archaeal and eukaryotic cell cycle control.

Nicosulfuron is a sulfonylurea herbicide widely used for weed control in maize fields. Its soil residues can cause phytotoxicity in rotation crops sensitive to this compound, such as wheat and cabbage, making the development of rapid, sensitive detection methods essential. Building on a hapten synthesized in prior work, this study employed single B cell technology to generate rabbit-derived monoclonal antibodies — an approach that directly recovers naturally paired heavy and light chains, offering superior reproducibility and consistency compared to traditional hybridoma methods. Using the top-performing monoclonal antibody 6D8, the team developed two complementary rapid detection platforms: an indirect competitive ELISA and a lateral flow immunoassay (LFIA) based on colloidal gold, with systematic optimization of buffer composition and matrix interference effects. Both methods demonstrated exceptional sensitivity and specificity, with very low cross-reactivity against 11 structurally analogous compounds; spiked sample recoveries correlated closely with UPLC-MS/MS reference measurements. The study also used molecular docking to elucidate the antibody–nicosulfuron binding mechanism, revealing key hydrogen bond interaction sites and providing a structural basis for future antibody engineering. These tools offer practical, field-deployable solutions for monitoring nicosulfuron residues in soil and agricultural products, with direct implications for guiding rational herbicide use.

The mechanisms underlying resistance to Bt Cry1Ac toxin in the diamondback moth (Plutella xylostella) remain a central question in sustainable pest management. This study found that elevated titers of 20-hydroxyecdysone (20E) in resistant moths are driven by the downregulation of two 20E-degrading enzymes (EO and GLD) — though this alone is insufficient to fully account for the resistance phenotype. From a panel of 13 aldo-keto reductase (AKR) candidates, the researchers identified the 3-dehydroecdysone-3β-reductase (3DE3βR) gene, which catalyzes the reduction of 3-dehydroecdysone (3DE) to biologically active 20E. Gene knockdown experiments confirmed that suppressing Px3DE3βR expression significantly reduced 20E levels, attenuated MAPK signaling pathway activation, and ultimately diminished resistance to Cry1Ac. Molecular docking analysis revealed high-affinity binding of Px3DE3βR to both 3DE and 3D20E. These findings demonstrate that Px3DE3βR enhances Bt resistance by augmenting 20E biosynthesis, identifying it as a novel target for resistance management strategies.

Monkeypox virus (MPXV) has evolved from an endemic tropical disease into a global public health threat. Current diagnostic approaches are heavily reliant on PCR, which is difficult to deploy rapidly in resource-limited settings, underscoring the need for accessible and accurate diagnostic tools. This study targeted the MPXV envelope protein A29L as an antigen, screening six high-affinity monoclonal antibodies via mouse immunization and hybridoma technology, followed by comprehensive characterization including isotyping, variable region sequencing, and neutralization activity assessment. Using the optimal antibody pair (mAb#94/Bio-5), the team developed two complementary diagnostic platforms: a high-sensitivity sandwich ELISA with a detection limit as low as 31.25 pg/mL, achieving 95% sensitivity and 100% specificity in plasma samples — outperforming existing commercial kits; and a colloidal gold-based lateral flow immunoassay (LFIA) capable of 100% detection in high-viral-load samples, suitable for rapid point-of-care screening. The authors proposed a tiered diagnostic strategy using the high-sensitivity ELISA as a laboratory confirmation tool and the rapid LFIA as a frontline screening instrument, effectively bridging the gap between centralized confirmatory testing and decentralized field surveillance — and providing a practical diagnostic solution for strengthening global monkeypox response capacity.

Common carp rank among the most important freshwater aquaculture species globally, with females growing significantly faster than males — making all-female populations a highly effective strategy for improving yield. Conventional approaches rely on exogenous androgens or aromatase inhibitors to induce sex reversal in females, producing pseudo-males that are then crossed with wild-type females to generate all-female offspring; however, this method is hampered by inconsistent efficacy, operational complexity, and potential environmental contamination risks. High-temperature induction of sex reversal has emerged as a more eco-friendly alternative, with demonstrated success in Indian carp species, yet direct application of the same protocol to Yellow River carp yielded limited results. This study systematically evaluated the effects of high-temperature treatment at different developmental stages on sex reversal in Yellow River carp, and made a key discovery: high temperature can not only induce primary sex reversal before sex differentiation, but also trigger secondary sex reversal in females with already-differentiated gonads — with the latter showing significantly higher reversal efficiency, marking the first report of thermally induced secondary sex reversal in fish. The study further tracked the histological progression of ovary-to-testis transformation and dynamic expression changes of sex differentiation-related genes, confirming that secondary sex reversal proceeds through classical sex differentiation signaling pathways. Pseudo-males produced by this method displayed normal sperm quality with fertilization and hatching rates comparable to those of wild-type males; testicular function remained stable long-term without regression. All offspring were phenotypically female, with genetic sex confirmed as XX. This work offers a new green production strategy for generating all-female Yellow River carp populations.