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Long-lived emissive nucleic acid probes are widely used in biochemical analysis due to their programmable structures, high signal-to-background ratio, and high sensitivity. Homogeneous detection based on long-lived emissive nucleic acid probes is often achieved through Förster resonance energy transfer (FRET), which suffers from the limitation of a narrow effective distance range. Herein, a new strategy of accessing nucleic acid hybridization-responsive luminescent probes is presented. The photoluminescence (PL) of a Lumi4-Tb complex internally modified with DNA is switched on by nucleic acid hybridization, after which the PL is increased up to 20 times. PL lifetime analysis revealed a possible mechanism of luminescence enhancement. Due to the flexibility of single-stranded nucleic acid chains, the bases and phosphate groups can coordinate with the Tb(III), which reduces the stability of the Tb complex and results in weak PL. After hybridization, the rigid double helix structure suppresses the coordination between Tb(III) and the bases or phosphate groups, causing luminescence enhancement. As the DNA sequence can be freely designed, an array of probes for different DNA or RNA targets can be created with the same Tb complex. Moreover, the novel probe design can afford pM detection limits of DNA or RNA without any nucleic acid amplification and exhibits great potential for nucleic acid detection in clinical diagnosis.

To evaluate the effects of lactylate and Bacillus subtilison growth performance, complete blood cell count, and microbial changes, 264 weaning pigs were assigned to 4 treatments (1) control (Con) basal diets that met the nutrient requirement for each phase, (2) 0.2% lactylate (LA), (3) 0.05% Bacillus subtilisstrains mixtures (BM) providing 2 x 105CFU/g of complete feed, or (4) the combination of LA and BM (LA+BM) added to the control basal diet at their respective inclusion rates in each of the 3 phases. Dietary lactylate tended to increase weight gain, significantly increased feed intake, and reduced fecal total E. coliand enterotoxigenic E. colicounts during Phase 1. Pigs fed Bacillus subtilishad a greater gain to feed ratio (G:F) during Phases 1 and 2. Pigs fed lactylate had an increased peripheral absolute neutrophil count on D14 but a decreased eosinophil percentage. Pigs fed Bacillus subtilishad an elevated peripheral total white blood cell count at study completion. The addition of lactylate increased microbiota richness, reduced E. coli, and increased Prevotella, Christensenellaceae, and Succinivibrio. Bacillus subtilis supplementation-enriched f_Ruminococcaceae_unclassified and S24-7_ unclassified had positive relationships with feed efficiency. Collectively, these findings suggested that lactylate can be added to diets to balance gut microbiota and improve growth performance during the early postweaning period. The combination of lactylate and Bacillus subtilisstrains exerted a synergic effect on the growth performance of nursery pigs.

A method for fast and highly sensitive detection of antibodies in serum would greatly facilitate the early diagnosis of disease and infection and dose optimization of therapeutic antibody. Bioluminescence detection with LUMABS (renamed mNeonG-LUMABS, where mNeonG is short for mNeonGreen) sensors based on bioluminescence resonance energy transfer (BRET) between blue-emitting luciferase Nluc and green fluorescent protein (FP) mNeonGreen has been demonstrated to enable fast detection of antibodies directly in serum with reasonable sensitivity. However, some mNeonG-LUMABS sensors exhibit low sensitivity, and thus, sensitivity improvement remains imperative. Here, we report a bright green FP, Clover4, obtained by structure-guided mutagenesis of green FP Clover. Despite similar brightness and fluorescence spectra of Clover and mNeonGreen, Clover4-LUMABS sensors exhibit a largely increased dynamic range (maximum 20-fold) and much lower limit of detection (LOD) (maximum 5.6-fold), most likely because Clover4 is positioned in a more parallel orientation to Nluc in LUMABS. Due to modular design, Clover4-LUMABS offers a general BRET system for fast and highly sensitive antibody detection in serum.