CBT‐Cys click reaction for optical bioimaging in vivo

Abstract Derived from the D‐luciferin regeneration pathway in firefly body, the click condensation reaction between 2‐cyanobenzothiazole (CBT) and D‐cysteine (Cys) (CBT‐Cys click reaction) possesses unique advantages, including superior biocompatibility, high second order reaction rate, and metal‐free mild conditions, emerging as a powerful bioorthogonal tool for a variety of chemical biological applications. Moreover, owing to its programmable controllability (e.g., pH, reduction, or enzyme), CBT‐Cys click reaction is exploited to fabricate stimuli‐activatable imaging probes with self‐assembling behaviors in physiological context. At stimuli‐rich pathological lesions of interest, these probes undergo CBT‐Cys click reaction to form cyclic dimers/oligomers or linear polymers, and further self‐assemble into nanostructures. The in situ formed nanostructures promote the selective accumulation and retention of imaging agent cargos at pathological lesions, thus enabling precise and enhanced in vivo imaging of diseases (especially tumors). To address the significance and recent breakthroughs of smart CBT‐Cys probes for enhanced optical imaging of tumors/other diseases, we herein propose this mini‐review, in which advances (particularly in recent 5 years) and potential challenges (or chances) in this field are emphasized

Dietary supplementation with fermented antarctic krill shell improved the growth performance, digestive and antioxidant capability of Macrobrachium nipponense

To investigate the effects of different levels of fermented antarctic krill shell (FAKS) on the growth performance, hemolymph biochemistry, hepatopancreatic antioxidant capacity, and digestive enzyme activities of Macrobrachium nipponense, five isonitrogenous and isoenergetic experimental diets containing different proportions of FAKS (0 %, 0.25 %, 0.5 %, 1.0 %, 2.0 %) were fed to M. nipponense for 8 weeks. The results showed the weight gain rate (WGR), specific growth rate (SGR), head-to-body ratio (H/S), and head-to-tail ratio (H/T) increased first and then decreased with higher proportions of FAKS. The FAKS1.0 group exhibited the highest values, and significantly higher than that of the FAKS0 group (P < 0.05). Compared with the control group, FAKS inclusion could increase the concentration of hemolymph albumin (ALB), and reduce the concentration of alkaline phosphatase (ALP) (P < 0.05). The concentration of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly lower in the FAKS1.0 group (P < 0.05). The hepatopancreas trypsin (TPS) concentration in the FAKS1.0 group, and the lipoprotein lipase (LPL) concentration in the FAKS0.25, FAKS0.5 and FAKS1.0 groups were significantly higher than that in other groups respectively (P < 0.05). With increasing proportions of FAKS, the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and ceruloplasmin (CP) in the hepatopancreas tended to increase and then decrease, and were significantly higher in the FAKS0.5 group than that in the FAKS0 group (P < 0.05). The concentration of malondialdehyde (MDA) in the FAKS0.25, FAKS0.5 and FAKS1.0 groups was significantly lower than that in the FAKS0 group (P < 0.05). In conclusion, adding a certain level of FAKS to the feed significantly improved the growth performance, digestive enzyme, and antioxidant enzyme activity of M. nipponense. Based on the quadratic regression curve fitting, the optimal WGR and SGR can be achieved when the proportion of dietary FAKS is 1.140 % and 1.149 %, respectively