Comparative analysis on bioactivity against three stored insects of Ligusticum pteridophyllum Franch. rhizomes essential oil and supercritical fluid (SFE-CO2) extract.

In order to develop more environmentally benignant insecticides, the Ligusticum pteridophyllum Franch. rhizomes essential oil and supercritical fluid (SFE-CO2) extract were obtained by two published techniques, hydrodistillation and SFE-CO2. The chemical components of this two tested samples were identified by using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detector (GC-FID). Repellent activity and contact toxicity of the obtained samples and myristicin against the adults of Tribolium castaneum (Coleoptera: Tenebrionidae), Lasioderma serricorne (Coleoptera: Anobiidae), and Liposcelis bostrychophila (Psocoptera: Liposcelididae) were compared. Nineteen components were identified in the SFE-CO2 extract. Twelve components were identified in the L. pteridophyllum rhizomes essential oil. SFE-CO2 extract exhibited higher contact toxicity against T. castaneum, L. serricorne, and L. bostrychophila (LD50 = 69.60 µg/adult, 14.58 µg/adult, and 1.69 µg/cm2, respectively) than that of L. pteridophyllum rhizomes essential oil (LD50 = 87.99 µg/adult, 89.82 µg/adult, and 7.87 µg/cm2, respectively). Besides, myristicin (LD50 = 36.46 µg/adult) showed superior contact toxicity against T. castaneum than that of the L. pteridophyllum rhizomes essential oil and SFE-CO2 extract. It possessed potentially practical significance to develop L. pteridophyllum rhizomes into plant pesticide or repellent agent for these stored insect controls. Graphical abstract .

Seven herbs against the stored product insect: Toxicity evidence and the active sesquiterpenes from Atractylodes lancea.

In this work, the essential oils (EO) were extracted from seven typical Chinese herbs, and their repellent and contact toxicities against Tribolium castaneum adults (red flour beetles) were evaluated. The experimental results showed that the above EOs presented the various levels of repellent and contact toxicities. The EOs extracted from A. lancea and A argyi of the Compositae (Asteraceae) family presented obvious repellent effects (Repellency Percentage > 90% at 3.15 nL/cm2 after 4 h exposure) and strong contact toxicity with LD50 values of 5.78 and 3.09 µg/adult respectively. Based on literature researches and screening results, the EO from A. lancea was analyzed by GC-MS and chosen for further identification of bioactive components. Altogether 59 chemical components were identified and 17 of them were recognized as sesquiterpene compounds, accounting for 57.8% of the total weight of the EO. From the identified sesquiterpenes, three individual compounds (ß-eudesmol, hinesol, valencene) were selected for the laboratory bioassays of the toxicity against red flour beetles. It was found that all the three compounds expressed some repellent effects. Although ß-eudesmol (31.2%) and hinesol (5.1%) were identified as main constituents and had been considered to be symbolic characteristics of high medicinal value, valencene (0.3%) showed strong repellent property which could be comparable to that of DEET (N, N­diethyl­3­methylbenzamide), a powerful commercial pesticides, and it had best toxicity with LD50 values of 3.25 (µg/adult) in the contact test. This work may provide toxicity evidence of seven common herbs against red flour beetles, add the information for the development and comprehensive utilization of A. lancea, and will contribute to the application of grain preservation.

Supercritical carbon dioxide extract of Cinnamomum cassia bark: toxicity and repellency against two stored-product beetle species.

The extract from Cinnamomum cassia Presl bark was obtained with supercritical CO2 fluid extraction (SFE). Chemical components of the SFE extract were characterized by GC-MS spectrometry. The repellency and contact toxicity of the SFE extract were evaluated against the adults of Tribolium castaneum and Lasioderma serricorne along with those of its two main compounds. The results of GC-MS analysis indicated that 33 volatile constituents were identified from the extract. The main components included trans-cinnamaldehyde (32.1%), 3,3-dimethylhexane (10.6%) and 2,4-di-tert-butylphenol (7.9%). Testing results showed that the SFE extract had potent contact toxicity against T. castaneum and L. serricorne with LD50 values of 3.96 and 23.89 µg/adult, respectively. LD50 values of trans-cinnamaldehyde against T. castaneum and L. serricorne were 5.78 and 3.24 µg/adult, respectively. Additionally, percentage repellency values of the SFE extract and trans-cinnamaldehyde against T. castaneum and L. serricorne were rather high (PR = 100% and PR > 90%, respectively) at 78.63 and 15.73 nL/cm2 at 2 h post-exposure. 2,4-Di-tert-butylphenol showed some repellency against both beetle species. Considering its insecticidal and repellent effects, the SFE extract from C. cassia bark might be used in integrated pest management programs for T. castaneum and L. serricorne.

Immunization with a ZmpB-based protein vaccine could protect against pneumococcal diseases in mice.

Zinc metalloprotease B (ZmpB) is present in all isolated pneumococcal strains and contributes to the pathogenesis of pneumococcal infection. In this study, recombinant ZmpB was cloned and expressed in Escherichia coli. The expression of ZmpB by different pneumococcal strains was detectable by Western blotting with antisera raised to recombinant ZmpB. Flow cytometry analysis demonstrated that anti-ZmpB polyclonal antibodies could bind to the cell surface of the pneumococcal strains analyzed. Both recombinant ZmpB protein and anti-ZmpB polyclonal antibodies significantly inhibited the adhesion of Streptococcus pneumoniae D39 to A549 cells. In mouse models, mucosal immunization with recombinant ZmpB could significantly reduce pneumococcal lung colonization caused by S. pneumoniae serotypes 19F and 14 and significantly increase mice survival times following invasive pneumococcal challenge with different pneumococcal strains, including serotypes 2, 3, 6B, and 14. Furthermore, intraperitoneal immunization with recombinant ZmpB in combination with the recombinant pneumolysin mutant (DeltaA146 Ply) and heat shock protein 40 (DnaJ) could enhance the protection against pneumococcal infection compared to protection provided by single-protein antigens. Passive immunization with hyperimmune antisera against these three antigens also demonstrated that the combination of three hyperimmune antisera could provide better protection than single antisera. Taken together, our results suggest that ZmpB is a good candidate pneumococcal vaccine antigen.