Activity

Moreover, two tetrasubstituted benzidine derivatives other than TMB (4OCH 3 and 2OCH 3 2CH 3 ) were synthesized for comparison. It turned out that the performances (sensitivity, color purity, and stability of the colored products) of TMB are still superior, thus chemically confirming its status of “the chosen substrate” in colorimetric assays.We developed a simple and rapid method for analyzing nonproteinogenic amino acids that does not require conventional chromatographic equipment. In this technique, nonproteinogenic amino acids were first converted to a proteinogenic amino acid through in vitro metabolism in a cell extract. The proteinogenic amino acid generated from the nonproteinogenic precursors were then incorporated into a reporter protein using a cell-free protein synthesis system. The titers of the nonproteinogenic amino acids could be readily quantified by measuring the activity of reporter proteins. This method, which combines the enzymatic conversion of target amino acids with translational analysis, makes amino acid analysis more accessible while minimizing the cost and time requirements. We anticipate that the same strategy could be extended to the detection of diverse biochemical molecules with clinical and industrial implications.A self-sterilizing strategy based on antimicrobial organic agent release is proposed for polymeric membrane sensors to prevent marine biofouling. A solid-contact polymeric membrane calcium ion-selective electrode (Ca2+-ISE) is selected as a model sensor. 6-Cholorindole (6-Cl indole) is utilized as the biocidal agent due to its potential antimicrobial activity and environmental friendliness. The plasticized polymeric membrane doped with 6-Cl indole shows a markedly improved antimicrobial activity against the bacterial cells collected from seawater and effectively prevents the formation of a biofilm on the sensor surface, while displaying response properties (i.e., linear range, selectivity, and response time) similar to those of the undoped membrane. Importantly, the present sensor can preserve an improved antimicrobial activity when kept in the artificial seawater for 45 days, indicating highly stable antibacterial properties of the membrane electrode. Additionally, the 6-Cl indole-doped Ca2+-ISE exhibits no significant loss of analytical performance after exposure to a rather concentrated bacterial suspension (∼109 colony-forming units per mL (CFU mL-1)) for 7 days. The proposed antimicrobial agent release methodology can be extended to develop polymeric membrane-based marine sensors with stable biofouling resistances against bacterial colonization.Formation of halogenated disinfection byproducts (DBPs) from pharmaceutically active compounds has been observed in water supply systems following wastewater chlorination. Although research has been limited thus far, several studies have shown that halogenated DBPs may elicit increased toxicity compared to their parent compounds. For example, the lipid regulator gemfibrozil has been shown to form chlorogemfibrozil (Cl-gemfibrozil) and bromogemfibrozil (Br-gemfibrozil) following chlorination, which are more potent antiandrogens in male Japanese medaka (Oryzias latipes) compared to their parent compounds. In the present study, we aimed to characterize the bioaccumulative ability of halogenated gemfibrozil DBPs in marine polychaetes via chronic sediment exposures and, consequently, to assess the chronic and acute toxicity of halogenated gemfibrozil DBPs through sediment (in vivo) and aqueous (in vivo and in silico) toxicity evaluations. Following 28 day sediment exposures, Cl-gemfibrozil and Br-gemfibrozil bioaccumulated within Neanthes arenaceodentata, with both compounds reducing survival and growth. The biota-sediment accumulation factors determined for Cl-gemfibrozil and Br-gemfibrozil were 2.59 and 6.86, respectively. Furthermore, aqueous 96 h toxicity tests with N. arenaceodentata indicated that gemfibrozil DBPs elicited increased toxicity compared to the parent compound. While gemfibrozil had an acute LC50 value of 469.85 ± 0.096 mg/L, Cl-gemfibrozil and Br-gemfibrozil had LC50 values of 12.34 ± 0.085 and 9.54 ± 0.086 mg/L, respectively. Although acute toxicity is relatively low, our results indicate that halogenated gemfibrozil DBPs are bioaccumulative and may elicit effects in apex food web organisms prone to accumulation following lifelong exposures.Here, we demonstrate a novel donor-intermediate-receptor energy transfer model through a Ce3+ → Tb3+ → Eu3+ scheme in a CaTbAl3O7Ce3+,Eu3+ nanocrystalline phosphor. A new type of CaTbAl3O7 and CaTbAl3O7RE3+ (RE3+ = Ce3+ and/or Eu3+) nanocrystalline phosphors were prepared by a simple sol-gel method. There exist efficient energy transfers of Ce3+ → Tb3+, Tb3+ → Eu3+, and Ce3+ → Tb3+ → Eu3+ in CaTbAl3O7RE 3+ (RE 3+ = Ce3+ and/or Eu3+) nanocrystalline phosphors. With near-UV or UV light excitation, the as-prepared CaTbAl3O7RE 3+ (RE 3+ = Ce3+ and/or Eu3+) nanocrystalline phosphors’ luminous color can be regulated from green to green-yellow, yellow, orange, and orange-red by adjusting the doping concentration, categories, and different proportions of codoping Ce3+ to Eu3+ ions in the CaTbAl3O7 matrix. The luminescence mechanism with respect to the CaTbAl3O7RE3+ (RE3+ = Ce3+ and/or Eu3+) nanocrystalline phosphors has been tentatively proposed. NicotinamideRiboside Due to their excellent luminescence properties, the as-prepared CaTbAl3O7, CaTbAl3O7Ce3+, CaTbAl3O7Eu3+, and CaTbAl3O7Ce3+,Eu3+ nanocrystalline phosphors exhibit bright prospects in NUV-LEDs and other photoelectric field.The nonenzymatic replication of ribonucleic acid (RNA) may have enabled the propagation of genetic information during the origin of life. RNA copying can be initiated in the laboratory with chemically activated nucleotides, but continued copying requires a source of chemical energy for in situ nucleotide activation. Recent work has illuminated a potentially prebiotic cyanosulfidic chemistry that activates nucleotides, but its application to nonenzymatic RNA copying had not been demonstrated. Here, we report a novel pathway that activates RNA nucleotides in a manner compatible with template-directed nonenzymatic copying. We show that this pathway, which we refer to as bridge-forming activation, selectively yields the reactive imidazolium-bridged dinucleotide intermediate required for copying. Our results will enable more realistic simulations of RNA propagation based on continuous in situ nucleotide activation.