Multicopy Chromosome Integration and Deletion of Negative Global Regulators Significantly Increased the Heterologous Production of Aborycin in Streptomyces coelicolor.

Aborycin is a type I lasso peptide with a stable interlocked structure, offering a favorable framework for drug development. The aborycin biosynthetic gene cluster gul from marine sponge-associated Streptomyces sp. HNS054 was cloned and integrated into the chromosome of S. coelicolor hosts with different copies. The three-copy gul-integration strain S. coelicolor M1346::3gul showed superior production compared to the one-copy or two-copy gul-integration strains, and the total titer reached approximately 10.4 mg/L, i.e., 2.1 times that of the native strain. Then, five regulatory genes, phoU (SCO4228), wblA (SCO3579), SCO1712, orrA (SCO3008) and gntR (SCO1678), which reportedly have negative effects on secondary metabolism, were further knocked out from the M1346::3gul genome by CRISPR/Cas9 technology. While the ΔSCO1712 mutant showed a significant decrease (4.6 mg/L) and the ΔphoU mutant showed no significant improvement (12.1 mg/L) in aborycin production, the ΔwblA, ΔorrA and ΔgntR mutations significantly improved the aborycin titers to approximately 23.6 mg/L, 56.3 mg/L and 48.2 mg/L, respectively, which were among the highest heterologous yields for lasso peptides in both Escherichia coli systems and Streptomyces systems. Thus, this study provides important clues for future studies on enhancing antibiotic production in Streptomyces systems.

Acute toxicity of Zanthoxylum bungeanum against two stored product insects and synergistic interactions between two major compounds limonene and linalool.

In order to find and develop new botanical pesticides against storage pests, components of the essential oil (EO) from Zanthoxylum bungeanum were identified by GC-MS and their insecticidal activity against the stored product pests were studied. The EO was obtained by steam distillation. Results showed that EO was rich in limonene (23.67), linalool (21.76) and linalyl anthranilate (10.87). In contact assays, linalool exhibited strongest toxicity to red flour beetle adult (LD50 = 17.06 µg/adult) and larvae (LD50 = 16.42 µg/larvae), and linalool was the most active one against the Lasioderma serricorne (LD50 = 15.36 µg/larvae). Then limonene and linalool showed different levels of fumigant activities against the two insect species. Synergism effect existed in the proportion of contact assays against Tribolium castaneum adults, and additive was observed in the proportion of 7:1 against T. castaneum larvae. This work provides important information for the development and utilization of Z. bungeanum and suggests that the EO of Z. bungeanum has the potential to serve as bio-insecticides for controlling pest damage in stored products.

Insecticidal and acetylcholine esterase inhibition activity of Rhododendron thymifolium essential oil and its main constituent against two stored product insects.

In this work, we investigated the bioactivities of the essential oil (EO) extracted from the Rhododendron thymifolium and its principal germacrone against Lasioderma serricorne and Tribolium castaneum. The EO was obtained by steam distillation. Germacrone was obtained by cryogenic crystallization. The bioactivity of EO and germacrone was tested via contact and repellent activity assays. The results showed that EO and germacrone possessed contact and repellent activities against two species of insects. EO exhibited obvious contact activity against the L. serricorn adults, larvae and T. castaneum larvae with LD50 values of 29.15 µg/adult, 42.73 µg/larva, 19.65 µg/larva respectively. Germacrone exhibited excellent contact activity against the L. serricorne adults, larvae and the T. castaneum larvae with LD50 values of 17.18 µg/adult, 20.94 µg/larva, 20.93 µg/larva respectively. And at the highest testing concentrations (78.63 and 15.73 nL/cm2), the repellent activity of EO and germacrone on two target insects was comparable to that of the positive control (DEET) after 30 h exposure. In especially, in the treatment of the 120 h after the repellent activity of EO and germacrone against T.castaneum adults and larvae were still very significant and showed the same level percentage repellency as DEET. Meanwhile, germacrone exhibited inhibition of acetylcholinesterase activity with IC50 values of 3%. The results indicated that the EO of R. thymifolium and germacrone had the potential to be developed as natural insecticides and repellents for the control of T. castaneum and L. serricorne.

Toxicity and Synergistic Effect of Elsholtzia Ciliata Essential Oil and Its Main Components Against the Adult and Larval Stages of Tribolium Castaneum.

Investigations have indicated that storage pests pose a great threat to global food security by damaging food crops and other food products derived from plants. Essential oils are proven to have significant effects on a large number of stored grain insects. This study evaluated the contact toxicity and fumigant activity of the essential oil extract from the aerial parts of Elsholtzia ciliata and its two major biochemical components against adults and larvae of the food storage pest beetle Tribolium castaneum. Gas chromatography-mass spectrometry analysis revealed 16 different components derived from the essential oil of E. ciliata, which included carvone (31.63%), limonene (22.05%), and α-caryophyllene (15.47%). Contact toxicity assay showed that the essential oil extract exhibited a microgram-level of killing activity against T. castaneum adults (lethal dose 50 (LD50) = 7.79 µg/adult) and larvae (LD50 = 24.87 µg/larva). Fumigant toxicity assay showed LD50 of 11.61 mg/L air for adults and 8.73 mg/L air for larvae. Carvone and limonene also exhibited various levels of bioactivity. A binary mixture (2:6) of carvone and limonene displayed obvious contact toxicity against T. castaneum adults (LD50 = 10.84 µg/adult) and larvae (LD50 = 30.62 µg/larva). Furthermore, carvone and limonene exhibited synergistic fumigant activity against T. castaneum larvae at a 1:7 ratio. Altogether, our results suggest that E. ciliata essential oil and its two monomers have a potential application value to eliminate T. castaneum.

Fumigant and repellent activities of essential oil extracted from Artemisia dubia and its main compounds against two stored product pests.

The major chemical constituents of the essential oil extracted from Artemisia dubia wall. ex Bess. (Family: Asteraceae) were found as terpinolene (19.02%), limonene (17.40%), 2,5-etheno[4.2.2]propella-3,7,9-triene (11.29%), isoelemicin (11.05%) and p-cymene-8-ol (5.93%). Terpinolene and limonene were separated as main components from the essential oil. The essential oil showed fumigant toxicity against Tribolium castaneum and Liposcelis bostrychophila with LC50 values of 49.54 and 0.74 mg/L, respectively. The essential oil and isolated compounds of A. dubia showed repellency activities against both insects. Terpinolene and limonene showed the fumigant toxicity against T. castaneum. Terpinolene showed obvious fumigant toxicity against L. bostrychophila. The results indicated that the essential oil of A. dubia had potential to be developed into natural insecticides for controlling stored product pests.

Repellent activity of essential oils extracted from five Artemisia species against Tribolium castaneum (Coleoptera: Tenebrionidae) / Actividad repelente de aceites esenciales extraídos de cinco especies de Artemisia contra Tribolium castaneum (Coleoptera: Tenebrionidae)

Artemisia genus (family Asteraceae) has been widely used as medicines and cosmetic. The chemical compositions of essential oils extracted from five Artemisia species (A. anethoides, A. giraldii, A. roxburghiana, A. rubripes and A. sacrorum) were analyzed and the repellent activities of five essential oils were investigated by testing percent repellency (PR) in petri dish against Tribolium castaneum. By GC-MS analysis, the common components of the five essential oils were eucalyptol (11.09%-50.05%), camphor (6.28%-33.10%), terpinen- 4-ol (2.46%-12.41%), ß-caryophyllene (0.63%-10.68%) and germacrene D (2.28%-10.01%). 3,3,6-trimethyl-1,4-heptadien-6-ol (11.72%), 2-isopropyl-5-methyl-3-cyclohexen-1-one (24.80%) and ß-farnesene (12.23%) were the characteristic compounds in essential oils of A. sacrorum, A. anethoides and A. rubripes respectively. The essential oils of five plants showed repellent activity against T. castaneum. The PR of others four essential oils were comparable with DEET expect for A. sacrorum. The results indicated that the essential oils of A. anethoides, A. giraldii, A. roxburghiana and A. rubripes had the potential to be developed as repellent for control of T. castaneum.

El género Artemisia (familia Asteraceae) ha sido ampliamente utilizado como medicamentos y cosméticos. Se analizaron las composiciones químicas de los aceites esenciales extraídos de cinco especies de Artemisia (A. anethoides, A. giraldii, A. roxburghiana, A. rubripes y A. sacrorum) y se investigaron las actividades repelentes de cinco aceites esenciales mediante la prueba de repelencia porcentual (PR) en placa de petri contra Tribolium castaneum. Por análisis GC-MS, los componentes comunes de los cinco aceites esenciales fueron eucaliptol (11,09% -50,05%), alcanfor (6,28% -33,10%), terpinen-4-ol (2,46% -12,41%), ß-cariofileno 0,63% -10,68%) y germacrén D (2,28% -10,01%). 3,3,6-trimetil-1,4-heptadien-6-ol (11,72%), 2-isopropil-5-metil-3-ciclohexen-1-ona (24,80%) y ß-farneseno (12,23%). Los compuestos característicos en los aceites esenciales de A. sacrorum, A. anethoides y A. rubripes respectivamente. Los aceites esenciales de cinco plantas mostraron actividad repelente contra T. castaneum. El PR de otros cuatro aceites esenciales eran comparables con DEET esperado para A. sacrorum. Los resultados indicaron que los aceites esenciales de A. anethoides, A. giraldii, A. roxburghiana y A. rubripes tienen el potencial de ser desarrollados como repelentes para el control de T. castaneum.

Repellence of the main components from the essential oil of Glycosmis lucida Wall. ex Huang against two stored product insects.

A screening of Chinese medicinal herbs and wild plants for agrochemicals was carried out; the essential oil of Glycosmis lucida leaves was found to possess significant repellent activity against Tribolium castaneum and Liposcelis bostrychophila. It was found that the main components included elixene (19.81%), spathulenol (10.68%), anethole (12.05%), verbenone (10.32%) followed by ß-caryophyllene (6.87%). The essential oil, anethole and verbenone were strongly repellent against T. castaneum (96, 86 and 94%, respectively, at 15.73 nL cm-2) and L. bostrychophila (100, 68 and 72%, respectively, at 31.58 nL cm-2) after a 2h treatment. The results indicate that anethole and verbenone had the potential to be developed as natural repellents for control of stored product insects.

Bioactivities and Chemical Constituents of Essential Oil Extracted from Artemisia anethoides Against Two Stored Product Insects.

The chemical constituents of the essential oil extracted from Artemisia anethoides and the bioactivities of essential oil against Tribolium castaneum and Lasioderma serricorne were investigated. The main components of the essential oil were 1,8-cineole (36.54%), 2-isopropyl-5-methyl-3-cyclohexen-1-one (10.40%), terpinen-4-ol (8.58%), 2-isopropyltoluene (6.20) and pinocarveol (5.08%). The essential oil of A. anethoides possessed contact and fumigant toxicities against T. castaneum adults (LD50 = 28.80 µg/adult and LC50 = 13.05 mg/L air, respectively) and against L. serricorne (LD50 = 24.03 µg/adult and LD50 = 8.04 mg/L air, respectively). The crude oil showed repellent activity against T. castaneum and L. serricorne. Especially, the percentage repellency of essential oil was same level with DEET (positive control) against T. castaneum. The results indicated that the essential oil of A. anethoides had the potential to be developed as insecticide and repellent for control of T. castaneum and L. serricorne.

Chemical Constituents and Insecticidal Activities of Ajania fruticulosa Essential Oil.

The insecticidal activity and chemical constituents of the essential oil from Ajania fruticulosa were investigated. Twelve constituents representing 91.0% of the essential oil were identified, and the main constituents were 1,8-cineole (41.40%), (+)-camphor (32.10%), and myrtenol (8.15%). The essential oil exhibited contact toxicity against Tribolium castaneum and Liposcelis bostrychophila adults with LD50 values of 105.67 µg/adult and 89.85 µg/cm(2) , respectively. The essential oil also showed fumigant toxicity against two species of insect with LC50 values of 11.52 and 0.65 mg/l, respectively. 1,8-Cineole exhibited excellent fumigant toxicity (LC50  = 5.47 mg/l) against T. castaneum. (+)-Camphor showed obvious fumigant toxicity (LC50  = 0.43 mg/l) against L. bostrychophila. Myrtenol showed contact toxicity (LD50  = 29.40 µg/cm(2) ) and fumigant toxicity (LC50  = 0.50 mg/l) against L. bostrychophila. 1,8-Cineole and (+)-camphor showed strong insecticidal activity to some important insects, and they are main constituents of A. fruticulosa essential oil. The two compounds may be related to insecticidal activity of A. fruticulosa essential oil against T. castaneum and L. bostrychophila.

Essential Oil of Amomum maximum Roxb. and Its Bioactivities against Two Stored-Product Insects.

Amomum maximum Roxb. is a perennial herb distributed in South China and Southeast Asia. The objective of this work was to analyze the chemical constituents and assess insecticidal and repellent activities of the essential oil from Amomum maximum fruits against Tribolium castaneum (Herbst) and Liposcelis bostrychophila (Badonnel). The essential oil was obtained by hydrodistillation and analyzed by gas chromatography-flame ionization detector and gas chromatography-mass spectrometry. The main components of the essential oil were identified to be ß-pinene (23.39%), ß-caryophyllene (16.43%), α-pinene (7.55%), sylvestrene (6.61%) and ç-cadinene (4.19%). It was found that the essential oil of A. maximum fruits possessed contact and fumigant toxicities against T. castaneum adults (LD50 = 29.57 µg/adult and LC(50) = 23.09 mg/L air, respectively) and showed contact toxicity against L. bostrychophila (LD(50) = 67.46 µg/cm(2)). Repellency of the crude oil was also evaluated. After 2 h treatment, the essential oil possessed 100% repellency at 78.63 nL/cm(2) against T. castaneum and 84% repellency at 63.17 nL/cm(2) against L. bostrychophila. The results indicated that the essential oil of A. maximum fruits had the potential to be developed as a natural insecticide and repellent for control of T. castaneum and L. bostrychophila.

Chemical Composition and Bioactivities of the Essential Oil from Etlingera yunnanensis against Two Stored Product Insects.

The chemical composition of the essential oil of Etlingera yunnanensis rhizomes and its contact and repellent activities against Tribolium castaneum (Herbst) and Liposcelis bostrychophila (Badonnel) were investigated. The essential oil obtained from E. yunnanensis rhizomes with hydrodistillation was performed by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. The main components of the essential oil were identified to be estragole (65.2%), ß-caryophyllene (6.4%), 1,8-cineole (6.4%), limonene (5.2%), and α-pinene (2.4%). It was found that the essential oil of E. yunnanensis rhizomes possessed contact toxicity against T. castaneum and L. bostrychophila (LD50 = 23.33 µg/adult and LD50 = 47.38 µg/cm², respectively). Estragole, 1,8-cineole, and limonene exhibited stronger contact toxicity (LD50 values of 20.41, 18.86, and 13.40 µg/adult, respectively) than ß-caryophyllene (LD50 = 41.72 µg/adult) against T. castaneum adults. Estragole possessed stronger contact toxicity (LD50 = 30.22 µg/cm²) than ß-caryophyllene, 1,8-cineole, and limonene (LD50 values of 74.11, 321.20, and 239.62 µg/adult, respectively) against L. bostrychophila adults. Repellency of the crude oil was also evaluated. The essential oil and constituents possessed strong repellent activity against T. castaneum adults. The four individual constituents showed weaker repellent activity than the essential oil against L. bostrychophila adults. The results indicated that the essential oil of E. yunnanensis rhizomes and the individual constituents had the potential to be developed as a natural insecticide and repellent for the control of T. castaneum and L. bostrychophila.

Combination of pharmacophore hypothesis, genetic function approximation model, and molecular docking to identify novel inhibitors of S6K1.

S6K1 has emerged as a potential target for the treatment for obesity, type II diabetes and cancer diseases. Discovery of S6K1 inhibitors has thus attracted much attention in recent years. In this investigation, a hybrid virtual screening method that involves pharmacophore hypothesis, genetic function approximation (GFA) model, and molecular docking technology has been used to discover S6K1 inhibitors especially with novel scaffolds. The common feature pharmacophore hypothesis and GFA regression model of S6K1 inhibitors were first developed and applied in a virtual screen of the Specs database for retrieving S6K1 inhibitors. Then, the molecular docking method was carried out to re-filter these screened compounds. Finally, 60 compounds with promising S6K1 inhibitory activity were carefully selected and have been handed over to the other group to complete the follow-up compound synthesis (or purchase) and activity test.