Population dynamics and species composition of maize field parasitoids attacking aphids in northeastern China.

Maize, Zea mays L., is the most abundant field crop in China. Aphids are the most economically damaging pest on maize, particularly in the maize agri-ecosystems of Jilin Province, northeastern China. Parasitic wasps are important natural enemies of aphids, but limited information exists about their species composition, richness and seasonal dynamics in northeastern China. In this study, the population dynamics of maize aphids and parasitoid wasps were assessed in relation to each other during the summer seasons of two consecutive years, 2018 and 2019. We selected maize fields in the Changchun, Songyuan, Huinan and Gongzhuling areas of Jilin Province. Four species of aphids were recorded from these maize fields: Rhopalosiphum padi (L), Rhopalosiphum maidis (Fitch), Aphis gossypii Glover and Macrosiphum miscanthi (Takahashi). The dominant species in each of the four areas were R. maids (Filch) and R. padi in Changchun, R. padi in Songyuan, A. gossypii and R. padi in Huinan, and A.gossypii and R. padi in Gongzhuling. We delineated a species complex made up of primary parasitoids and hyperparasitoids associated with maize aphids. The primary parasitoids Lysiphlebus testaceipes, Binodoxys communis and Aphelinus albipodus together formed approximately 85.3% of the parasitoid complex. Pachyneuron aphidis, Phaenoglyphis villosa, Syrphophagus taeniatus and Asaphes suspensus made up the hyperparasitoids. Of the primary parasitoids, L. testaceipes was the dominant species (81.31%). Of the hyperparasitoid group, P. villosa was the dominant species (68.42%). Parasitism rates followed the fluctuation of the aphid population. The highest parasitic rate was observed during the peak period of cotton aphids. In this paper, the occurrence dynamics and dominant species of aphids and the dynamics of parasitic natural enemies of aphids in maize fields in Jilin Province are, for the first time, systematically reported. This study provides important information for the establishment and promotion of aphid biological control in maize fields.

A molecular detection approach for a cotton aphid-parasitoid complex in northern China.

Aphid-parasitoid interactions have been widely used as a model system in research studies on the structure and functions of arthropod food web. Research on aphid-parasitoid food webs is hindered by their micromorphological characteristics and the high amount of labor associated with their development. Species-specific primers for cotton aphids and their parasitoids were designed and integrated into two multiplex PCRs and six singleplex PCRs, and all PCRs were optimized to achieve high specificity and sensitivity (100-10,000 DNA copies). One cotton aphid (Aphis gossypii) as well as three primary parasitoid and seven hyperparasitoid species or genera were detected using this molecular approach. This group comprises all the primary parasitoids and 97.2-99.6% of the hyperparasitoids reported in cotton fields in northern China. A tritrophic aphid-primary parasitoid-hyperparasitoid food web was then established. The described method constitutes an efficient tool for quantitatively describing the aphid-primary parasitoid-hyperparasitoid food webs and assessing the efficiency of the biological control of parasitoids in cotton fields in northern China.

Flexible bronchoscopy-guided microwave ablation in peripheral porcine lung: a new minimally-invasive ablation.

BACKGROUND: Transbronchial lung biopsy is an important approach to diagnose peripheral lung cancer, but bronchoscopy based treatment options are limited and poorly studied. A flexible bronchoscopy-guided water-cooled microwave ablation (MWA) catheter was developed to evaluate the feasibility and safety both in ex vivo and in vivo porcine models. METHODS: Using direct penetration of the catheter through the surface of ex vivo porcine lung, ablations (n=9) were performed at 70, 80, 90 W for 10 minutes. Temperatures of the catheter and 10, 15, 20 mm away from the tip were measured. Under bronchoscopy conditions in porcine lung, ablations (n=18, 6 in ex vivo and 12 in vivo) were performed at 80 W for 5 minutes. Computed tomography (CT) was acquired perioperative, 24 hours, 2 weeks, and 4 weeks post ablation. Ablation zones were excised at 24 hours and 4 weeks respectively. Long-axis diameter (Dl) and short-axis diameter (Ds) were measured and tissues were sectioned for pathological examination. RESULTS: In-ex vivo lung, the temperature at 20 mm removed was over 60 °C at 80 W for 288±26 seconds. The ablations under bronchoscopic conditions were successful in-ex vivo and in vivo lung. No complications occurred during the procedures. Coagulation necrosis was visible at 24 hours, and repaired fibrous tissue was seen at 4 weeks. CONCLUSIONS: The flexible bronchoscopy-guided water-cooled MWA is feasible and safe. This early animal data holds promise of MWA becoming a potential therapeutic tool for Peripheral Lung Cancers.

[Levels of amino acids in cerebral spinal fluid in children with cerebral palsy].

OBJECTIVE: To study the changes of amino acids in cerebral spinal fluid (CSF) in children with spastic or athetotic cerebral palsy (CP) by examining CSF levels of glutamic acid (Glu), gamma-aminobutyric acid (GABA) and aspartate (ASP). METHODS: CSF samples were obtained from 13 children with spastic CP, from 14 children with athetotic CP, and from 10 children without central nervous system and infectious diseases (control group). CSF levels of Glu, GABA and ASP were determined by high-performance liquid chromatography. RESULTS: CSF levels of GABA, ASP and Glu in the control group were 13.04+/-2.19, 10.21+/-0.45 and 8.41+/-2.26 micromol/L, respectively. Compared with the control group, CSF GABA levels in the spastic and the athetotic CP groups (8.02+/-2.03 and 10.01+/-2.68 micromol/L respectively) significantly decreased (P<0.01), whereas CSF levels of Glu (20.99+/-8.15 and 28.77+/-17.62 micromol/L respectively) and Asp (13.53+/-3.93 and 14.02+/-2.88 micromol/L respectively) in the spastic and the athetotic CP groups significantly increased (P<0.01). There were statistical differences in the GABA level between the spastic and the athetotic CP groups (P<0.05). In children with spastic CPCSF Glu level was positively correlated to muscle tension. CONCLUSIONS: CSF excitatory amino acid levels increased, while CSF inhibitory amino acid levels decreased in children with CP. There were differences for CSF amino acid levels in different types of CP. The changes of amino acid levels may contribute to the pathogenesis of CP.

Lethal, sublethal and transgenerational effects of the novel chiral neonicotinoid pesticide cycloxaprid on demographic and behavioral traits of Aphis gossypii (Hemiptera: Aphididae).

Aphis gossypii Glover (Hemiptera: Aphididae) is a key pest in cotton crops, notably owing to its increasing resistance to commonly used pesticides. Such resistance prompts for the development of integrated pest management (IPM) programs that include novel pesticides being effective against the aphid. In the present study, we assessed lethal and sublethal effects of cycloxaprid, a novel chiral neonicotinoid pesticide developed in China, on A. gossypii. The lethal concentration at 50% (LC50 ) value of cycloxaprid on A. gossypii was estimated, using the dipping method, at 7.73 mg/L. The impact of a sublethal concentration (LC10 ) and a lethal concentration (LC40 ) of cycloxaprid on A. gossypii population growth and feeding behavior (using electrical penetration graph technique [EPG]), and its transgenerational effect were further assessed. Adult longevity and fecundity significantly decreased after exposure to LC40 or LC10 of cycloxaprid. Cycloxaprid with sublethal concentrations (especially LC40 ) had negative effects on phloem ingestion by A. gossypii. Additionally, the offspring of the adults exposed to LC40 of cycloxaprid had shorter nymphal development duration and adult longevity than the control, and those from LC10 and LC40 treatments had lower adult fecundity and net productive rate. We demonstrated that cycloxaprid is a pesticide showing both lethal and sublethal activities, and transgenerational effects on A. gossypii; it may be useful for implementation in IPM programs against this aphid pest.

Molecular Characterization and Expression Profiling of Odorant-Binding Proteins in Apolygus lucorum.

Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is one of the most important agricultural pests, with broad host range and cryptic feeding habits in China. Chemosensory behavior plays an important role in many crucial stages in the life of A. lucorum, such as the detection of sex pheromone cues during mate pursuit and fragrant odorants during flowering host plant localization. Odorant-binding proteins (OBPs) are involved in the initial biochemical recognition steps in semiochemical perception. In the present study, a transcriptomics-based approach was used to identify potential OBPs in A. lucorum. In total, 38 putative OBP genes were identified, corresponding to 26 'classic' OBPs and 12 'Plus-C' OBPs. Phylogenetic analysis revealed that A. lucorum OBP proteins are more closely related to the OBP proteins of other mirid bugs as the same family OBP clustering together. Quantitative real-time PCR analysis for the first reported 23 AlucOBPs revealed that the expression level of 11 AlucOBP genes were significantly higher in antennae of both sexes than in other tissues. Three of them were male antennae-biased and six were female antennae-biased, suggesting their putative roles in the detection of female sex pheromones and host plant volatiles. In addition, three, four, two and one AlucOBPs had the highest degree of enrichment in the stylet, head, leg, and in abdomen tissues, respectively. Two other OBPs were ubiquitously expressed in the main tissues, including antennae, stylets, heads, legs and wings. Most orthologs had similar expression patterns, strongly indicating that these genes have the same function in olfaction and gustation.