Acaricidal activity of usnic acid and sodium usnic acid against Psoroptes cuniculi in vitro

Natural Products as Mite Control Agents in Animals: A Review

Mites have been a persistent infectious disease affecting both humans and animals since ancient times. In veterinary clinics, the primary approach for treating and managing mite infestations has long been the use of chemical acaricides. However, the widespread use of these chemicals has resulted in significant problems, including drug resistance, drug residues, and environmental pollution, limiting their effectiveness. To address these challenges, researchers have shifted their focus towards natural products that have shown promise both in the laboratory and real-world settings against mite infestations. Natural products have a wide variety of chemical structures and biological activities, including acaricidal properties. This article offers a comprehensive review of the acaricidal capabilities and mechanisms of action of natural products like plant extracts, natural compounds, algae, and microbial metabolites against common animal mites.

Characterization of Sunflower Oil Extracts from the Lichen Usnea barbata

The increasing global emergence of multidrug resistant (MDR) pathogens is categorized as one of the most important health problems. Therefore, the discovery of novel antimicrobials is of the utmost importance. Lichens provide a rich source of natural products including unique polyketides and polyphenols. Many of them display pharmaceutical benefits. The aim of this study was directed towards the characterization of sunflower oil extracts from the fruticose lichen, Usnea barbata. The concentration of the major polyketide, usnic acid, was 1.6 mg/mL extract as determined by NMR analysis of the crude mixture corresponding to 80 mg per g of the dried lichen. The total phenolics and flavonoids were determined by photometric assays as 4.4 mg/mL (gallic acid equivalent) and 0.27 mg/mL (rutin equivalent) corresponding to 220 mg/g and 13.7 mg/g lichen, respectively. Gram-positive (e.g., Enterococcus faecalis) and Gram-negative bacteria, as well as clinical isolates of infected chickens were sensitive against these extracts as determined by agar diffusion tests. Most of these activities increased in the presence of zinc salts. The data suggest the potential usage of U. barbata extracts as natural additives and mild antibiotics in animal husbandry, especially against enterococcosis in poultry.

Divergent domains of 28S ribosomal RNA gene: DNA barcodes for molecular classification and identification of mites

BACKGROUND

The morphological and molecular identification of mites is challenging due to the large number of species, the microscopic size of the organisms, diverse phenotypes of the same species, similar morphology of different species and a shortage of molecular data.

METHODS

Nine medically important mite species belonging to six families, i.e. Demodex folliculorum, D. brevis, D. canis, D. caprae, Sarcoptes scabiei canis, Psoroptes cuniculi, Dermatophagoides farinae, Cheyletus malaccensis and Ornithonyssus bacoti, were collected and subjected to DNA barcoding. Sequences of cox1, 16S and 12S mtDNA, as well as ITS, 18S and 28S rDNA from mites were retrieved from GenBank and used as candidate genes. Sequence alignment and analysis identified 28S rDNA as the suitable target gene. Subsequently, universal primers of divergent domains were designed for molecular identification of 125 mite samples. Finally, the universality of the divergent domains with high identification efficiency was evaluated in Acari to screen DNA barcodes for mites.

RESULTS

Domains D5 (67.65%), D6 (62.71%) and D8 (77.59%) of the 28S rRNA gene had a significantly higher sequencing success rate, compared to domains D2 (19.20%), D3 (20.00%) and D7 (15.12%). The successful divergent domains all matched the closely-related species in GenBank with an identity of 74-100% and a coverage rate of 92-100%. Phylogenetic analysis also supported this result. Moreover, the three divergent domains had their own advantages. D5 had the lowest intraspecies divergence (0-1.26%), D6 had the maximum barcoding gap (10.54%) and the shortest sequence length (192-241 bp), and D8 had the longest indels (241 bp). Further universality analysis showed that the primers of the three divergent domains were suitable for identification across 225 species of 40 families in Acari.

CONCLUSIONS

This study confirmed that domains D5, D6 and D8 of 28S rDNA are universal DNA barcodes for molecular classification and identification of mites. 28S rDNA, as a powerful supplement for cox1 mtDNA 5'-end 648-bp fragment, recommended by the International Barcode of Life (IBOL), will provide great potential in molecular identification of mites in future studies because of its universality.

Inhibition of growth of U87MG human glioblastoma cells by Usnea longissima Ach

Herbal medicines are efficient to reduce side effects in the fight against glioblastoma, which plays a critical role within brain cancer species. The recent studies designated for testing the effects of lichens that have shown numerous anticancer activities on glioblastoma so far. In the present study, different concentrations of water extract obtained from Usnea longissima Ach. were used in order to determine cytotoxic (via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase tests), antioxidant (via total antioxidant capacity test), pro-oxidant (via total oxidant status test) and genotoxic (via 8-hydroxy-2'-deoxyguanosine test) effects of them on human U87MG-glioblastoma cancer cell lines. Primary mixed glial-neuronal non-cancerous cells from Sprague-Dawley rats were also utilized to measure the effects of treatments on non-cancerous cells. Based on median inhibitory concentration values, the data belonged to non-cancerous cells (2486.71 mg/L) showed distinct towering compared to U87MG (80.93 mg/L) cells. The viability of non-cancerous and U87MG cells exposed to extract is decreased in a dose dependent manner. It was also showed that low concentrations of extract notably increased total antioxidant capacity on non-cancerous cells. In addition, various phenolic compounds in extract were detected through high-performance liquid chromatography. The recent results encourage that extract will be able to have therapeutic potential against glioblastoma.

Population identification and divergence threshold in Psoroptidae based on ribosomal ITS2 and mitochondrial COI genes

Psoroptidae mites are a type of small mites with a wide range of hosts. The proliferation of Psoroptidae mites could cause symptoms such as severe itching, atopic dermatitis, and hair loss in infected animals. If severely infected, death can also occur. The morphological classification and identification of Psoroptidae mites is problematic due to the overlapping geographical distribution. In addition, there is no divergence threshold for molecular classification and identification. To solve this problem, gDNA was extracted from individual Psoroptes and Otodectes mites (China) for amplification of rDNA ITS2 and mtDNA COI. After that, the sequences obtained were aligned and analyzed with those retrieved from GenBank. Based on rDNA ITS2 sequences, Psoroptidae was divided into three genera, namely, Psoroptes, Chorioptes, and Otodectes, which was in accordance with morphological classification. The intraspecies, interspecies, and intergenera could be differentiated effectively, with thresholds ≤ 5.20, 6.18-14.86, and ≥15.72 %, respectively. However, based on mtDNA COI sequences, Psoroptidae was divided into four genera with Caparinia added, as Caparinia sp did not cluster with the other three genera. The intra- and interspecies could be differentiated effectively, but interspecies and intergenera could not. The intra- and interspecies identification thresholds were ≤ 2.12 and ≥10.93 %. Further analysis showed that host but not geographical isolation was found in Psoroptes and Chorioptes, whereas Otodectes mites parasitizing dogs and cats were the same species; neither host nor geographical isolation was observed. In conclusion, rDNA ITS2 is better than mtDNA COI for DNA barcoding in Psoroptidae.