Enhanced absorbance detection system for online bacterial monitoring in digital microfluidics.

We report a fully integrated digital microfluidic absorbance detection system with an enhanced sensitivity for online bacterial monitoring. Through a 100 µm gap in the chip, our optical detection system has a detection sensitivity for a BCA protein concentration of 0.1 mg mL-1. The absorbance detection limit of our system is 1.4 × 10-3 OD units, which is one order of magnitude better than that of the existing studies. The system's linear region is 0.1-7 mg mL-1, and the dynamic range is 0-25 mg mL-1. We measured the growth curves of wild-type and E. coli transformed with resistance plasmids and mixed at different ratios on chip. We sorted out the bacterial species including highly viable single cells based on the difference in absorbance data of growth curves. We explored the changes in the growth curves of E. coli under different concentrations of resistant media. In addition, we successfully screened for the optimal growth environment of the bacteria, in which the growth rate of PET30a-DH5α (in a medium with 33 µg mL-1 kanamycin resistance) was significantly higher than that of a 1 mg mL-1 resistance medium. In conclusion, the enhanced digital microfluidic absorbance detection system exhibits exceptional sensitivity, enabling precise bacterial monitoring and growth curve analysis, while also laying the foundation for DMF-based automated bioresearch platforms, thus advancing research in the life sciences.

Diagnostic performance of US-based FNAB criteria of the 2020 Chinese guideline for malignant thyroid nodules: comparison with the 2017 American College of Radiology guideline, the 2015 American Thyroid Association guideline, and the 2016 Korean Thyroid Association guideline.

BACKGROUND: To investigate the diagnostic performance of the ultrasonography-based fine-needle aspiration biopsy criteria of the Chinese Thyroid Imaging Reporting and Data System (C-TIRADS) for malignant nodules compared to 3 other guidelines. METHODS: This study included 2,309 thyroid nodules in 1,697 patients with histopathological and cytopathological diagnoses of benign and malignant nodules from January 2018 to August 2020. The clinical and ultrasonographic features of the nodules were retrospectively reviewed and classified according to the Chinese guideline (C-TIRADS), the American College of Radiology guideline (ACR-TIRADS), the American Thyroid Association guideline (ATA guideline), and the Korean Thyroid Association guideline (K-TIRADS). The diagnostic performance of the guidelines and their unnecessary fine-needle aspiration biopsy rates were calculated using randomized, blinded trials. RESULTS: Of the 2,309 nodules, 1,418 (61.4%) were benign and 891 (38.6%) were malignant, with 884 (99.21%) papillary carcinomas. The accuracy of C-TIRADS was 84.71%, followed by the guidelines of ACR-TIRADS (82.11%), K-TIRADS (81.64%), and the ATA guideline (78.56%). Furthermore, the area under the receiver operating characteristic curve (AUC) was the highest for the C-TIRADS (0.905). Similar results were revealed for both the diagnostic performance and AUC of nodules smaller and larger than 10 mm. The ACR-TIRADS showed the lowest unnecessary biopsy rate (17.54%), followed by the C-TIRADS (22.61%), ATA guideline (27.90%), and the K-TIRADS (28.67%). CONCLUSIONS: The C-TIRADS demonstrated high diagnostic performance and a relatively low unnecessary biopsy rate in detecting thyroid cancer compared to the 3 other guidelines. However, further understanding of the ultrasonography-based fine-needle aspiration biopsy criteria of the C-TIRADS should be gained in the future.

Effect of Femtosecond Laser in Situ Keratomileusis on the Choriocapillaris Perfusion and Choroidal Thickness in Myopic Patients.

PURPOSE: To investigate changes in choriocapillaris vascular density (CCD) and choroidal thickness (CT) after femtosecond laser in situ keratomileusis (FS-LASIK) in myopic patients. METHODS: Prospective and observational self-control study. We enrolled 41 myopic patients (41 right eyes), without other ophthalmic or systemic diseases who were eligible and about to FS-LASIK surgery. The CCD was measured in the central 1-mm-diameter circle region of the macular fovea (CCD1) and the 1- to 3-mm ring-like region of the fovea (CCD1-3). The CT was measured at the fovea and at distances of 0.5 and 2.5 mm for the following: nasal, temporal, superior, and inferior to the fovea. Both were measured by optical coherence tomography angiography (OCTA) preoperatively as the baseline and at 1 day, 1 week, 1 month, and 3 months postoperatively. RESULTS: CCD1 and CCD1-3 were significantly lower postoperatively compared with baseline. When the trough was reached, CCD1 declined by 1.51%, and CCD1-3 declined by 1.00% at 1 day postoperatively. However, then they increased with time. CCD1 recovered to baseline at 1 month postoperatively, while CCD1-3 was still lower at the end of follow-up. In addition, the CT was significantly thicker postoperatively and recovered to the baseline at 3 months postoperatively. There was no obvious correlation between CCD, CT, and other parameters. CONCLUSIONS: The CCD decreased while the CT increased following FS-LASIK in myopic patients. However, these changes may be a temporary stress response rather than real irreversible injury to the choroid.

An asymmetric allelic interaction drives allele transmission bias in interspecific rice hybrids.

Hybrid sterility (HS) between Oryza sativa (Asian rice) and O. glaberrima (African rice) is mainly controlled by the S1 locus. However, our limited understanding of the HS mechanism hampers utilization of the strong interspecific heterosis. Here, we show that three closely linked genes (S1A4, S1TPR, and S1A6) in the African S1 allele (S1-g) constitute a killer-protector system that eliminates gametes carrying the Asian allele (S1-s). In Asian-African rice hybrids (S1-gS1-s), the S1TPR-S1A4-S1A6 interaction in sporophytic tissues generates an abortion signal to male and female gametes. However, S1TPR can rescue S1-g gametes, while the S1-s gametes selectively abort for lacking S1TPR. Knockout of any of the S1-g genes eliminates the HS. Evolutionary analysis suggests that S1 may have arisen from newly evolved genes, multi-step recombination, and nucleotide variations. Our findings will help to overcome the interspecific reproductive barrier and use Asian-African hybrids for increasing rice production.

The Intronic cis Element SE1 Recruits trans-Acting Repressor Complexes to Repress the Expression of ELONGATED UPPERMOST INTERNODE1 in Rice.

Plant height has a major effect on grain yield in crops such as rice (Oryza sativa), and the hormone gibberellic acid (GA) regulates many developmental processes that feed into plant height. Rice ELONGATED UPPERMOST INTERNODE1 (Eui1) encodes a GA-deactivating enzyme governing elongation of the uppermost internode. The expression of Eui1 is finely tuned, thereby maintaining homeostasis of endogenous bioactive GA and producing plants of normal plant height. Here, we identified a dominant dwarf mutant, dEui1, caused by the deletion of an RY motif-containing cis-silencing element (SE1) in the intron of Eui1. Detailed genetic and molecular analysis of SE1 revealed that this intronic cis element recruits at least one trans-acting repressor complex, containing the B3 repressors OsVAL2 and OsGD1, the SAP18 co-repressor, and the histone deacetylase OsHDA710, to negatively regulate the expression of Eui1. This complex generates closed chromatin at Eui1, suppressing Eui1 expression and modulating GA homeostasis. Loss of SE1 or dysfunction of the complex components impairs histone deacetylation and H3K27me3 methylation of Eui1 chromatin, thereby increasing Eui1 transcription and decreasing bioactive GA, producing dwarfism in rice. Together, our results reveal a novel silencing mechanism in which the intronic cis element SE1 negatively regulates Eui1 expression via repressor complexes that modulate histone deacetylation and/or methylation.