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A new phenylpropanoid, (+)-methyl 3-acetoxy-3-(7-methoxy-1,3-benzodioxol-5-yl) propanoate (1), was obtained from the 95% EtOH extract of entire plant of Peperomia tetraphylla. The structure was elucidated based on the spectral analysis (IR, 1-D and 2-D NMR and HRESIMS). The absolute configuration of 1 was determined as (3R) by referring to analogous compound's optical rotation. Cytotoxicity assays showed that compound 1 had a moderate inhibitory activity against the A549 cell line, weak inhibitory activity against the Hela and the HepG2 cell lines. [ABSTRACT FROM AUTHOR]

To assess the total effects of avermectin and for rational application, the effects of a sublethal concentration (the LC20 was chosen as a representative) of avermectin on the development and reproduction of the citrus red mite, Panonychus citri (McGregor), were evaluated at 26 ± 1°C, 70-75% relative humidity and a photoperiod of 14 : 10 h light : dark in the laboratory. The results showed that the sublethal dose of avermectin had no significant effect on the hatching rate of eggs and the emergence rate of the nymphs. However, after exposure to avermectin, females of the parental generation (F0) and progeny (F1 and F2) produced fewer eggs than did the control females. The larval and nymphal developmental periods were also affected significantly by exposure to avermectin. Furthermore, the pre-oviposition period as well as the adult longevity was shortened, resulting in a decrease of the mean generation time. Generally, the mites exposed with sublethal concentration of avermectin during the nymphal stages showed positive effects on population increase [i.e. higher intrinsic rate of increase (rm), net reproductive rate (R0), and finite rate of increase (λ) values, but shorter population doubling times (Dt)], whereas the mites treated during the adult stages had negative effects on population increase (i.e. lower rm, R0, and λ values, longer Dt). Such effects were more obvious at the F2 generation than at the F1 generation in both treatments. [ABSTRACT FROM AUTHOR]

A two-factorial experiment was designed to study the effects of temperature (10, 15, 20, and 25 °C) and light intensity (20, 60, 100, 140, and 180 μE·m-2·s-1) on the growth and biochemical composition of Sargassum thunbergii. The results showed that temperature, light intensity, and their interactions had significant effects on the growth of S. thunbergii. A higher growth rate of S. thunbergii was observed at 15 °C-20 °C, and, with the increase of temperature, the light intensity for the maximum growth rate of S. thunbergii had an increasing trend. At 10 °C and 15 °C, higher light intensity had definite inhibition effect on the growth of S. thunbergii; while at 20 °C and 25 °C, the growth rate was generally increased with increasing light intensity. Both temperature and light intensity had significant effects on the chlorophyll a and fucoxanthin contents of S. thunbergii, and the effects of light intensity was greater than those of temperature. In general, the chlorophyll a and fucoxanthin contents of S. thunbergii decreased significantly with increasing light intensity but increased with increasing temperature. The carbohydrate content of S. thunbergii increased with increasing light intensity, while no significant difference was observed at different temperature. The protein content of S. thunbergii decreased with increasing light intensity, and was higher at 10 °C and 15 °C but tented to decrease with increasing temperature. The variation of light intensity and temperature induced the changes in the biochemical composition of S. thunbergii, and these changes could be an active physiological adjustment for the adaptation to the variation of environmental factors, which was of ecological significance to the growth and survival of S. thunbergii. [ABSTRACT FROM AUTHOR]

The Asian citrus psyllid, Diaphorina citri , is the principal vector of Huanglongbing pathogen Candidatus Liberibacter asiaticus (CLas), which causes severe economic losses to citrus industry worldwide. Use of broad-spectrum insecticides to control D. citri has resulted in considerable resistance development. Specific chemosensory proteins such as odorant binding proteins (OBPs) are potentially involved in reduced insecticide susceptibility. However, functional data on the contribution of OBPs to reduced susceptibility of D. citri are unavailable. We found that DcitOBP2 was stably expressed in different developmental stages and highly expressed in the legs, head and cuticle of D. citri. Expression of DcitOBP2 was significantly induced by 12 to 48 h of imidacloprid exposure and ranged from a 1.34- to 2.44-fold increase. RNAi of DcitOBP2 increased the susceptibility of D. citri adults to imidacloprid. The purified recombinant protein of DcitOBP2 expressed in Escherichia coli showed strong in vitro binding activity (K d = 62.39 nM) to imidacloprid using microscale thermophoresis technology (MST). DcitOBP2 also had strong binding ability to thiamethoxam and dinotefuran but it had no response to abamectin, fenpropathrin and chlorpyrifos. The results showed that DcitOBP2 can interact with several neonicotinoid insecticides. This suggests that DcitOBP2 is involved in the decreased susceptibility of D. citri to imidacloprid. Our data reveal a new function of insect OBPs as a buffering protein that helps insects survive insecticide exposure. Our investigation may also aid in the development of new methods for resistance management of D. citri. Unlabelled Image • DcitOBP2 can be significantly induced by imidacloprid exposure. • RNAi of DcitOBP2 increased the susceptibility of D. citri to imidacloprid. • Recombinant protein DcitOBP2 had a strong binding property to imidacloprid in vitro. [ABSTRACT FROM AUTHOR]

Olfaction contributes to many crucial behaviors in insects, such as foraging, locating hosts, mating, and avoiding predators. In the first step of the olfaction process in insects, odorant-binding proteins (OBPs) bind with the odorants and transport hydrophobic odorants. OBPs are also believed to accelerate the termination of the odorant response. The oriental fruit fly, Bactrocera dorsalis , is one of the most destructive fruit-eating pests, causing enormous economic losses to the fruit and vegetable industry worldwide. However, information relating to the number, diversity, and expression patterns of OBPs still remains fragmented in this insect pest. Here, we attempted to identify the OBPs in B. dorsalis using genomic and transcriptomic information. In this study, we expanded the repository of B. dorsalis OBPs to 49. Phylogenetic analysis of BdorOBPs with other species revealed that these proteins grouped into four subfamilies. Furthermore, we determined the expression profiles in six body parts (namely, the legs, wings, antenna, cuticles of the head, thorax, and abdomen) and five internal tissues (namely, the fat body, midgut, Malpighian tubule, testis, and ovary). The results indicated that 21 BdorOBPs showed high expression levels in the antenna, legs, and head cuticles and may thus perform olfactory functions, which corroborates previous evidence. Two BdorOBPs were specifically expressed in the abdomen cuticles. Nineteen OBPs were highly expressed in the fat body, while four OBPs were highly expressed in the reproductive organs. This indicated that they may have physiological roles other than in chemoreception. In summary, our results contribute to the knowledge base of insect OBPs and provide a foundation for the further study of the molecular mechanisms of chemoreception in B. dorsalis. Unlabelled Image • We expanded the repository of B. dorsalis OBPs from 33 to 49. • We renamed the OBPs followed the Drosophila melanogaster nomenclature. • We determined the expression patterns of the OBPs in the outer body parts as well as the internal tissues. [ABSTRACT FROM AUTHOR]

Diaphorina citri Kuwayama (D. citri) is one of the major pests in the citrus industry, which spreads Citrus Huanglongbing disease. It has developed resistance to chemical insecticides. Therefore, searching for greener solutions for pest management is critically important. The main aim of this study was to evaluate the repellent and insecticidal efficacy of essential oils (EOs) from four species of Myrtaceae plants: Psidium guajava (PG), Eucalyptus robusta (ER), Eucalyptus tereticornis (ET), and Baeckea frutescens (BF) against D. citri and to analyze their chemical compositions. GC-MS analysis was performed, and the results indicated that the EOs of PG, ER, ET, and BF were rich in terpenoids, ketones, esters, and alcohol compounds. The repellent rate of all four EOs showed that it decreased with exposure time but increased with the concentration of EOs from 80.50% to 100.00% after treating D. citri for 6 h with four EOs at 100% concentration and decreased to 67.71% to 85.49% after 24 h of exposure. Among the compounds from the EOs tested, eucalyptol had the strongest repellent activity, with a 24 h repellency rate of 100%. The contact toxicity bioassay results showed that all EOs have insecticidal toxicity to D. citri; the LC50 for nymphs was 36.47–93.15 mL/L, and for adults, it was 60.72–111.00 mL/L. These results show that when PG is used as the reference material, the ER, ET, and BF EOs have strong biological activity against D. citri, which provides a scientific basis for the further development of plant-derived agrochemicals. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of the hybrid ofTakifugu flavidus(♀) × Takifugu rubripes(♂) was sequenced and characterized. The total length of the mitogenome is 16,443 bp. It contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 2 non-coding regions: origin of light-strand replication (OL) and control region (D-loop). The overall nucleotide composition of the heavy strand is 30.05% A, 25.79% T, 15.07% G and 29.09% C, with an A + T content of 55.84%. Except forND6gene and eight tRNA genes, other genes are encoded on the heavy strand. The complete mitogenome of the hybrid ofT. flavidus(♀) × T. rubripes(♂) should contribute to further studies on mitochondrial inheritance mechanism. [ABSTRACT FROM PUBLISHER]