Upon environmental changes, proliferating cells delay cell cycle to prevent further damage accumulation. Yeast Cip1 is a Cdk1 and Cln2-associated protein. However, the function and regulation of Cip1 are still poorly understood. Here we report that Cip1 expression is co-regulated by the cell-cycle-mediated factor Mcm1 and the stress-mediated factors Msn2/4. Overexpression of Cip1 arrests cell cycle through inhibition of Cdk1–G1 cyclin complexes at G1 stage and the stress-activated protein kinase-dependent Cip1 T65, T69, and T73 phosphorylation may strengthen the Cip1and Cdk1–G1 cyclin interaction. Cip1 accumulation mainly targets Cdk1–Cln3 complex to prevent Whi5 phosphorylation and inhibit early G1 progression. Under osmotic stress, Cip1 expression triggers transient G1 delay which plays a functionally redundant role with another hyperosmolar activated CKI, Sic1. These findings indicate that Cip1 functions similarly to mammalian p21 as a stress-induced CDK inhibitor to decelerate cell cycle through G1 cyclins to cope with environmental stresses.

Immobilization of proteins on magnetic nanoparticles (MNPs) is an effective approach to improve protein stability and facilitate separation of immobilized proteins for repeated use. Herein, we exploited the efficient SpyTag-SpyCatcher chemistry for conjugation of functional proteins onto MNPs and established a robust magnetic-responsive nanoparticle platform for protein immobilization. To maximize the loading capacity and achieve outstanding water dispersity, the SpyTag peptide was incorporated into the surface-charged polymers of MNPs, which provided abundant active sites for Spy chemistry while maintaining excellent colloidal stability in buffer solution. Conjugation between enhanced green fluorescence protein (EGFP)-SpyCatcher-fused proteins and SpyTag-functionalized MNPs was efficient at ambient conditions without adding enzymes or chemical cross-linkers. Benefiting from the excellent water dispersity and interface compatibility, the surface Spy reaction has fast kinetics, which is comparable to that of the solution Spy reaction. No activity loss was observed on EGFP after conjugation due to the site-selective nature of Spy chemistry. The immobilization process of EGFP on MNPs was highly specific and robust, which was not affected by the presence of other proteins and detergents, such as bovine serum albumin and Tween 20. The MNP platform was demonstrated to be protective to the conjugated EGFP and significantly improved the shelf life of immobilized proteins. In addition, experiments confirmed the retained magnetophoresis of the MNP after protein loading, demonstrating fast MNP recovery under an external magnetic field. This MNP is expected to provide a versatile and modular platform to achieve effective and specific immobilization of other functional proteins, enabling easy reuse and storage.

Prevention of mosquito-borne infectious diseases will require new classes of environmentally safe insecticides and novel mosquito control technologies. Saccharomyces cerevisiae was engineered to express short hairpin RNA (shRNA) corresponding to mosquito Rbfox1 genes. The yeast induced target gene silencing, resulting in larval death that was observed in both laboratory and outdoor semi-field trials conducted on Aedes aegypti. High levels of mortality were also observed during simulated field trials in which adult females consumed yeast delivered through a sugar bait. Mortality correlated with defects in the mosquito brain, in which a role for Rbfox1 as a positive regulator of Notch signaling was identified. The larvicidal and adulticidal activities of the yeast were subsequently confirmed in trials conducted on Aedes albopictus, Anopheles gambiae, and Culex quinquefasciatus, yet the yeast had no impact on survival of select non-target arthropods. These studies indicate that yeast RNAi pesticides targeting Rbfox1 could be further developed as broad-based mosquito larvicides and adulticides for deployment in integrated biorational mosquito control programs. These findings also suggest that the species-specificity of attractive targeted sugar baits, a new paradigm for vector control, could potentially be enhanced through RNAi technology, and specifically through the use of yeast-based interfering RNA pesticides.

Concerns for widespread insecticide resistance and the unintended impacts of insecticides on nontarget organisms have generated a pressing need for mosquito control innovations. A yeast RNAi-based insecticide that targets a conserved site in mosquito Irx family genes, but which has not yet been identified in the genomes of nontarget organisms, was developed and characterized. Saccharomyces cerevisiae constructed to express short hairpin RNA (shRNA) matching the target site induced significant Aedes aegypti larval death in both lab trials and outdoor semi-field evaluations. The yeast also induced high levels of mortality in adult females, which readily consumed yeast incorporated into an attractive targeted sugar bait (ATSB) during simulated field trials. A conserved requirement for Irx function as a regulator of proneural gene expression was observed in the mosquito brain, suggesting a possible mode of action. The larvicidal and adulticidal properties of the yeast were also verified in Aedes albopictus, Anopheles gambiae, and Culexquinquefasciatus mosquitoes, but the yeast larvicide was not toxic to other nontarget arthropods. These results indicate that further development and evaluation of this technology as an ecofriendly control intervention is warranted, and that ATSBs, an emerging mosquito control paradigm, could potentially be enriched through the use of yeast-based RNAi technology.

Background Occult scaphoid fractures on initial radiographs of an injury are a diagnostic challenge to physicians. Although artificial intelligence models based on the principles of deep convolutional neural networks (CNN) offer a potential method of detection, it is unknown how such models perform in the clinical setting. Questions/purposes (1) Does CNN-assisted image interpretation improve interobserver agreement for scaphoid fractures? (2) What is the sensitivity and specificity of image interpretation performed with and without CNN assistance (as stratified by type: normal scaphoid, occult fracture, and apparent fracture)? (3) Does CNN assistance improve time to diagnosis and physician confidence level? Methods This survey-based experiment presented 15 scaphoid radiographs (five normal, five apparent fractures, and five occult fractures) with and without CNN assistance to physicians in a variety of practice settings across the United States and Taiwan. Occult fractures were identified by follow-up CT scans or MRI. Participants met the following criteria: Postgraduate Year 3 or above resident physician in plastic surgery, orthopaedic surgery, or emergency medicine; hand fellows; and attending physicians. Among the 176 invited participants, 120 completed the survey and met the inclusion criteria. Of the participants, 31% (37 of 120) were fellowship-trained hand surgeons, 43% (52 of 120) were plastic surgeons, and 69% (83 of 120) were attending physicians. Most participants (73% [88 of 120]) worked in academic centers, whereas the remainder worked in large, urban private practice hospitals. Recruitment occurred between February 2022 and March 2022. Radiographs with CNN assistance were accompanied by predictions of fracture presence and gradient-weighted class activation mapping of the predicted fracture site. Sensitivity and specificity of the CNN-assisted physician diagnoses were calculated to assess diagnostic performance. We calculated interobserver agreement with the Gwet agreement coefficient (AC1). Physician diagnostic confidence was estimated using a self-assessment Likert scale, and the time to arrive at a diagnosis for each case was measured. Results Interobserver agreement among physicians for occult scaphoid radiographs was higher with CNN assistance than without (AC1 0.42 [95% CI 0.17 to 0.68] versus 0.06 [95% CI 0.00 to 0.17], respectively). No clinically relevant differences were observed in time to arrive at a diagnosis (18 ± 12 seconds versus 30 ± 27 seconds, mean difference 12 seconds [95% CI 6 to 17]; p < 0.001) or diagnostic confidence levels (7.2 ± 1.7 seconds versus 6.2 ± 1.6 seconds; mean difference 1 second [95% CI 0.5 to 1.3]; p < 0.001) for occult fractures. Conclusion CNN assistance improves physician diagnostic sensitivity and specificity as well as interobserver agreement for the diagnosis of occult scaphoid fractures. The differences observed in diagnostic speed and confidence is likely not clinically relevant. Despite these improvements in clinical diagnoses of scaphoid fractures with the CNN, it is unknown whether development and implementation of such models is cost effective. Level of Evidence Level II, diagnostic study.