Biology subjects

Cao, H.-H.

Publications and source records attributed to Cao, H.-H..

4 recordsLinked to original sources

bioRxiv2022

Influence of amino acids and glucosinolates in three Brassicaceae vegetable plants on preference and performance of the green peach aphid: Myzus persicae

The green peach aphid, Myzus persicae (Sulzer) is a generalist pest of various host plants, whose feeding preference and growth performance mainly depends on the quantity and quality of nutrients and defensive metabolites in host plants. Here, we studied the preference and performance of M. persicae on three major Brassicaceae vegetables in China and measured nutrient (amino acids) and defensive (glucosinolates) metabolites in these plants. We found that M. persicae preferred and performed better on Chinese cabbage than cabbage and radish, which may be due to the relatively higher concentration of amino acids and lower levels of glucosinolates in their leaves. The glucosinolates level in cabbage leaves was ten times higher than the other two plants, while the amino acid concentration in radish was only half of the cabbage or Chinese cabbage. The higher concentration of glucosinolates in cabbage and lower levels of amino acids in radish may account for the poorer preference and growth of M. persicae on these two plants. These results suggest that both amino acids and glucosinolates in plants are important determinants of the preference and performance of M. persicae, which provide new knowledge for the cultivation and breeding of Brassicaceae vegetables.

ecology↗

bioRxiv2020

Study on H3K9 acetylation modification and TLR9 immune regulation mechanism in patients with anti-HBV treatment using thymosin a1 combined with entecavir

For hepatitis B antiviral treatment, there has been no comprehensive method yet. Interferon has poor antiviral efficacy, while nucleoside drugs have long course of treatment and high relapse rate. To improve the anti-HBV curative effect, treatment methods such as thymosin combined with entecavir have become a focus of clinical investigation. To explore potential mechanism of the combination therapy, based on previous studies, this paper explores the relationship between TLR9 expression in PBMCs, secretion of corresponding downstream inflammatory factors and HBV load in anti-HBV treatment with Thymosin a1 (Ta1) combined with entecavir. Chromatin immunoprecipitation combined with PCR method was adopted to detect H3K9 acetylation modification in patients. The relationship between TLR9 expression was explored using RT-QPCR, the relationship between secretion of inflammatory factors, efficacy and TLR9 mRNA expression was determined using Luminex technology. The results showed that during anti-HBV treatment with Ta1 combined with entecavir, histone acetylation increased in patients PBMCs, acetylated protein H3K9Ac had significant binding with promoter region of the TRL9 gene, thereby increasing the expression of TRL9 mRNA, activating the immune pathway under TRL9 regulation, promoting secretion of inflammation factors IL-6, IL-12, IFN-{gamma}, and TNF-, boosting the progress of antiviral therapy. H3K9 acetylation modification of TLR9 exists and plays an important role in patients with chronic hepatitis B. During the combination therapy with entecavir and Ta1, histone acetylation modification of TLR9 was significantly improved, which increased the expression of TLR9 at the mRNA and protein levels, and further regulated IL-6, IL-12 and other cytokines.

pharmacology and toxicology↗

bioRxiv2018

Evaluation and optimization of the protocols for measuring cytochrome P450 activity in aphids

Cytochrome P450 enzymes play major roles in insect detoxification of plant toxins and insecticides. However, measuring P450 activity in aphids has variable success, and a reliable method is not available yet. In this study, we evaluated and optimized the method for measuring P450 activity in aphids using the 7-ethoxycoumarin as the substrate. First, we found that nicotinamide adenine dinucleotide phosphate and protective agents are not needed in the aphid P450 activity assay, and homogenizing the green peach aphid, Myzus persicae, in the microplate resulted in significantly higher P450 activities than those in Eppendorf tube. Homogenizing aphids in Eppendorf tube could grind tissues thoroughly and released uncharacterized compounds that could inhibit aphid and pig liver P450 activities, whereas aphids in the microplate likely could not be thoroughly ground and thus released fewer such inhibitors. Then, the microplate homogenization method was optimized to follows: one or two aphids were put into one well of the microplate and ground in phosphate buffer using pipette tips for 20 cycles, followed by addition of 7-ethoxycoumarin, and then incubated for 1 h at room temperature, after which glycine buffer-ethanol mixture was added to stop the reaction. This method is also suitable for the pea aphid, Acyrthosiphon pisum, and the bird cherry {square}oat aphid, Rhopalosiphum padi. These results emphasize the importance of considering inhibitory effect of endogenous compounds in insects on their P450 activity and provide one possible method to reduce this inhibitory effect.

biochemistry↗

bioRxiv2017

Nutrition Outweighs Defense: Myzus persicae (Green Peach Aphid) Prefers and Performs Better on Young Leaves of Cabbage

Plant leaves of different ages differ in nutrition and toxic metabolites and thus exhibit various resistance levels against insect herbivores. However, little is known about the relationship between leaf ontogeny and plant resistance against phloem-feeding insects. In this study, we found that the green peach aphid, Myzus persicae Sulzer, preferred to settle on young cabbage leaves (Brassica oleracea L. var. capitata) rather than mature or old leaves, although young leaves contained the highest concentration of glucosinolates. Furthermore, aphids feeding on young leaves had higher levels of glucosinolates in their bodies, but aphids performed better on young leaves in terms of body weight and population growth. The concentration of glutamine in young leaves was the highest, which stimulated aphids feeding when added to the sucrose solution. Phloem sap of young leaves had higher amino acid:sucrose molar ratio than mature leaves, and aphids feeding on young leaves showed two times longer phloem feeding time and five times more dry honeydew excretion than on other leaves. These results indicate that aphids acquired the highest amount of nutrition and defensive metabolites when feeding on young cabbage leaves that are strong natural plant sinks. The higher phloem sap availability of young leaves likely contributes to the attractiveness and suitability for aphids and may compensate the negative effects of glucosinolates on aphids. According to these findings, we propose that phloem sap availability influenced by leaf ontogeny and source-sink status play a significant role in plant-aphid interaction, which desires more attention in future research.

ecology↗