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Purple nutsedge (Cyperus rotundus L.) is a globally distributed noxious weed that poses a significant challenge for control due to its fast and efficient propagation through the tuber, which is the primary reproductive organ. Gibberellic acid (GA3) has proven to be crucial for tuberization in tuberous plants. Therefore, understanding the relationship between GA3 and tuber development and propagation of C. rotundus will provide valuable information for controlling this weed. This study shows that the GA3 content decreases with tuber development, which corresponds to lower expression of bioactive GA3 synthesis genes (CrGA20ox, two CrGA3ox genes) and two upregulated GA3 catabolism genes (CrGA2ox genes), indicating that GA3 is involved in tuber development. Simultaneously, the expression of two CrDELLA genes and CrGID1 declines with tuber growth and decreased GA3, and yeast two-hybrid assays confirm that the GA3 signaling is DELLA-dependent. Furthermore, exogenous application of GA3 markedly reduces the number and the width of tubers and represses the growth of the tuber chain, further confirming the negative impact that GA3 has on tuber development and propagation. Taken together, these results demonstrate that GA3 is involved in tuber development and regulated by the DELLA-dependent pathway in C. rotundus and plays a negative role in tuber development and propagation.
The microbiota–gut–brain axis, especially the microbial tryptophan (Trp) biosynthesis and metabolism pathway (MiTBamp), may play a critical role in the pathogenesis of major depressive disorder (MDD). However, studies on the MiTBamp in MDD are lacking. The aim of the present study was to analyze the gut microbiota composition and the MiTBamp in MDD patients.
We performed shotgun metagenomic sequencing of stool samples from 26 MDD patients and 29 healthy controls (HCs). In addition to the microbiota community and the MiTBamp analyses, we also built a classification based on the Random Forests (RF) and Boruta algorithm to identify the gut microbiota as biomarkers for MDD.
The Bacteroidetes abundance was strongly reduced whereas that of Actinobacteria was significantly increased in the MDD patients compared with the abundance in the HCs. Most noteworthy, the MDD patients had increased levels of Bifidobacterium, which is commonly used as a probiotic. Four Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologies (KOs) (K01817, K11358, K01626, K01667) abundances in the MiTBamp were significantly lower in the MDD group. Furthermore, we found a negative correlation between the K01626 abundance and the HAMD scores in the MDD group. Finally, RF classification at the genus level can achieve an area under the receiver operating characteristic curve of 0.890.
The present findings enabled a better understanding of the changes in gut microbiota and the related Trp pathway in MDD. Alterations of the gut microbiota may have the potential as biomarkers for distinguishing MDD patients form HCs.
Carbon nanodots (CDs) have generated enormous excitement because of their superiority in water solubility, chemical inertness, low toxicity, ease of functionalization and resistance to photobleaching. Here we report a facile thermal pyrolysis route to prepare CDs with high quantum yield (QY) using citric acid as the carbon source and ethylene diamine derivatives (EDAs) including triethylenetetramine (TETA), tetraethylenepentamine (TEPA) and polyene polyamine (PEPA) as the passivation agents. We find that the CDs prepared from EDAs, such as TETA, TEPA and PEPA, show relatively high photoluminescence (PL) QY (11.4, 10.6, and 9.8%, respectively) at λex of 465 nm. The cytotoxicity of the CDs has been investigated through in vitro and in vivo bio-imaging studies. The results indicate that these CDs possess low toxicity and good biocompatibility. The unique properties such as the high PL QY at large excitation wave length and the low toxicity of the resulting CDs make them promising fluorescent nanoprobes for applications in optical bio-imaging and biosensing.
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