The Effect of Volatile Oil from Chinese Mugwort Leaf on Human Demodecid Mites In Vitro

Genome sequencing reveals chromosome fusion and extensive expansion of genes related to secondary metabolism in Artemisia argyi

Artemisia argyi, as famous as Artemisia annua, is a medicinal plant with huge economic value in the genus of Artemisia and has been widely used in the world for about 3000 years. However, a lack of the reference genome severely hinders the understanding of genetic basis for the active ingredient synthesis of A. argyi. Here, we firstly report a complex chromosome-level genome assembly of A. argyi with a large size of 8.03 Gb, with features of high heterozygosity (2.36%), high repetitive sequences (73.59%) and a huge number of protein-coding genes (279 294 in total). The assembly reveals at least three rounds of whole-genome duplication (WGD) events, including a recent WGD event in the A. argyi genome, and a recent burst of transposable element, which may contribute to its large genome size. The genomic data and karyotype analyses confirmed that A. argyi is an allotetraploid with 34 chromosomes. Intragenome synteny analysis revealed that chromosomes fusion event occurred in the A. argyi genome, which elucidates the changes in basic chromosome numbers in Artemisia genus. Significant expansion of genes related to photosynthesis, DNA replication, stress responses and secondary metabolism were identified in A. argyi, explaining the extensive environmental adaptability and rapid growth characteristics. In addition, we analysed genes involved in the biosynthesis pathways of flavonoids and terpenoids, and found that extensive gene amplification and tandem duplication contributed to the high contents of metabolites in A. argyi. Overall, the reference genome assembly provides scientific support for evolutionary biology, functional genomics and breeding in A. argyi and other Artemisia species.

Evaluation of the in vitro acaricidal activity of Chinese herbal compounds on the poultry red mite (Dermanyssus gallinae)

The poultry red mite Dermanyssus gallinae is an economically important pest in poultry farms worldwide, but an effective treatment option is lacking. The current study determined the effectiveness of six Chinese herbal medicines [Syzygium aromaticum (clove), Hibiscus syriacus (Hibiscus), Illicium verum (star anise), Leonurus artemisia (motherwort), Cinnamomum cassia (cinnamon), and Taraxacum sp. (dandelion)] against D. gallinae. Alcohol extracts were prepared via the solvent extraction method and the phenol, flavonoid, and tannin contents were determined. These active components were highest in S. aromaticum and lowest in H. syriacus, I. verum. No tannin content was detected in L. artemisia. All extracts showed contact toxicity against D. gallinae at a test concentration of 1 g/mL, with S. aromaticum and L. artemisia resulting in 100% mortality. S. aromaticum, L. artemisia, and I. verum showed the best efficacy (LC₅₀ 0.159, 0.200, and 0.292 g/mL, respectively). Different combinations of extracts showed an additive effect of I. verum LC₉₀ + L. artemisia LC₉₀. The acaricidal efficacy of this combination was tested against different developmental stages of D. gallinae, being most efficacious against nymphal and larval D. gallinae, with a corrected mortality rate of 100%. However, inhibition of egg hatching was only 53.69%. Taken together, these results highlight I. verum LC₉₀ + L. artemisia LC₉₀ as a promising compound with severe contact toxicity against D. gallinae. Given the wide cultivation of these species and their extensive use in foodstuffs and cosmetics as flavors and fragrances, they could be a cheap, readily available ecofriendly alternative to pesticides currently used in poultry farms.

Evaluation of the in vitro acaricidal activity of ethanol extracts of seven Chinese medicinal herbs on Ornithonyssus sylviarum (Acari: Macronyssidae)

Ornithonyssus sylviarum (Acari: Macronyssidae) is a common ectoparasite that feeds on the blood of poultry. Following infestation, this mite will cause symptoms such as weight loss, anemia, and decreased egg production. To explore green and safe drugs for the prevention and treatment of O. sylviarum, this study evaluated the effects of ethanol extracts of seven Chinese medicinal herbs-Leonurus artemisia (motherwort), Illicium verum (star anise), Cinnamomum cassia (cinnamon), Hibiscus syriacus, Artemisia argyi (Chinese mugwort), Taraxacum sp. (dandelion), and Syzygium aromaticum (clove)-on O. sylviarum at different life stages. The results showed that different methods of administration affected the acaricidal efficacy of these plant extracts on O. sylviarum. After 6 h of administration with the fumigation method, the acaricidal efficacy of S. aromaticum on adults, nymphs and larvae of O. sylviarum reached 100%. 30 min after administration with the infiltration method, S. aromaticum, H. syriacus and L. artemisia showed acaricidal effects on adults and nymphs of O. sylviarum reaching 100%. In another experiment evaluating the inhibition of egg hatching of O. sylviarum with alcohol extracts of these seven herbs, at 48 h after treatment, A. argyi and C. cassia showed inhibition rates of 19.4%. The results of this study indicate that S. aromaticum induced mortality at all stages of O. sylviarum, whereas A. argyi was found to be the most effective at inhibiting the mite's egg hatching among the seven herbs. These herbs can therefore be used as potential substitutes for chemical pesticides to prevent and control O. sylviarum. These results provide practical knowledge for the control of O. sylviarum.

The comparative in vitro killing activity of tea tree oil versus permethrin on Demodex folliculorum of rosacea patients

BACKGROUND

Demodex mites have been implicated in several cutaneous disorders compelling the research efforts for effective anti-Demodex therapy.

OBJECTIVE

Compare the survival time (ST) of Demodex folliculorum exposed to six different concentrations of tea tree oil (TTO) versus a positive control (permethrin 5%) and a negative control (immersion oil) group.

MATERIALS AND METHODS

The wastes of rosacea patients' standardized superficial skin biopsy samples were recruited for the trial. The primary outcome measure of this study was the survival time, defined as the period between the exposure of study agents to the complete cessation of Demodex movements.

RESULTS

All differences between the mean survival times of 2.5% (54.0 ± 6.1), 5% (39.0 ± 3.9), 10% (22.0 ± 2.5), 25% (13.0 ± 2.5), 50% (7.8 ± 0.6), and 100% TTO (3.3 ± 1.3) were significant (p < 0.05). The ST of the negative control group was 196.0 ± 23.6 min. The ST of permethrin 5% was 12.5 ± 1.9 that did not show a statistically significant difference from the ST of TTO 25% (p = 0.628).

CONCLUSION

The survival times of the six different TTO groups confirmed a dose-related pattern, all of which had survival times shorter than the negative control (immersion oil). TTO 25% had comparable efficacy to the positive control agent (permethrin 5%).

Full-Length Transcriptome Analysis Reveals Candidate Genes Involved in Terpenoid Biosynthesis in Artemisia argyi

Artemisia argyi is an important medicinal plant widely utilized for moxibustion heat therapy in China. The terpenoid biosynthesis process in A. argyi is speculated to play a key role in conferring its medicinal value. However, the molecular mechanism underlying terpenoid biosynthesis remains unclear, in part because the reference genome of A. argyi is unavailable. Moreover, the full-length transcriptome of A. argyi has not yet been sequenced. Therefore, in this study, de novo transcriptome sequencing of A. argyi's root, stem, and leaf tissues was performed to obtain those candidate genes related to terpenoid biosynthesis, by combining the PacBio single-molecule real-time (SMRT) and Illumina sequencing NGS platforms. And more than 55.4 Gb of sequencing data and 108,846 full-length reads (non-chimeric) were generated by the Illumina and PacBio platform, respectively. Then, 53,043 consensus isoforms were clustered and used to represent 36,820 non-redundant transcripts, of which 34,839 (94.62%) were annotated in public databases. In the comparison sets of leaves vs roots, and leaves vs stems, 13,850 (7,566 up-regulated, 6,284 down-regulated) and 9,502 (5,284 up-regulated, 4,218 down-regulated) differentially expressed transcripts (DETs) were obtained, respectively. Specifically, the expression profile and KEGG functional enrichment analysis of these DETs indicated that they were significantly enriched in the biosynthesis of amino acids, carotenoids, diterpenoids and flavonoids, as well as the metabolism processes of glycine, serine and threonine. Moreover, multiple genes encoding significant enzymes or transcription factors related to diterpenoid biosynthesis were highly expressed in the A. argyi leaves. Additionally, several transcription factor families, such as RLK-Pelle_LRR-L-1 and RLK-Pelle_DLSV, were also identified. In conclusion, this study offers a valuable resource for transcriptome information, and provides a functional genomic foundation for further research on molecular mechanisms underlying the medicinal use of A. argyi leaves.