Dissipation and residue of triadimefon in Rosa roxburghii.

Rosa roxburghii (R. roxburghii) is a unique, edible, medicinal fruit rich in vitamin C found in Southwest China. Triadimefon (TDF) is a triazole fungicide that is widely used to control powdery mildew in R. roxburghii. To assess the safety of TDF in R. roxburghii, an LC-MS/MS method was developed for the simultaneous quantification of TDF and its major metabolite, triadimenol (TDN) in R. roxburghii. Both TDF and TDN showed high correlation coefficients (>0.999) for the solvent- and matrix-matched calibrations. The recovery rates of TDF and TDN in R. roxburghii ranged from 90.18% to 100.42%, with a relative standard deviation (RSD) of 1.25%-9.22%. The limit of quantification (LOQ) was 0.01 mg·kg-1. The half-life of TDF in R. roxburghii was between 2.74 and 3.07 days, with terminal residues ranging from < LOQ to 1.84 mg·kg-1. Recommended maximum residue limits (MRLs) and safe pre-harvest intervals (PHIs) for TDF in R. roxburghii were 0.5 mg·kg-1 and 21 days, respectively. This study provides essential data for TDF's safe and judicious use in R. roxburghii production.

Morphological and molecular characterization of Heterodera ripae, a new record cyst nematode in the rhizosphere soil of Fagopyrum esculentum.

Numerous plant parasitic nematodes (PPNs) have the potential to inflict considerable damage on agricultural crops. Through a comprehensive survey aimed at identifying PPNs affecting crops, cyst nematodes were isolated from the rhizosphere soil of buckwheat (Fagopyrum esculentum). Employing both molecular and morphological techniques, this cyst nematode was conclusively identified as Heterodera ripae. Notably, this represents the first documented occurrence of this particular cyst nematode species within the rhizosphere soil of F. esculentum.

Isolation, Identification, and Evaluation of the Predatory Activity of Chinese Arthrobotrys Species towards Economically Important Plant-Parasitic Nematodes.

The current investigation aimed to isolate and identify predatory fungal strains and evaluate their efficacy in mitigating the effects of plant-parasitic nematodes. We successfully isolated three distinct nematophagous fungal strains from soil samples, identified as Arthrobotrys megalosporus, A. oligospora, and A. sinensis, using conventional and molecular identification methodologies. In vitro trials illustrated the high capture efficiency of these fungi against plant-parasitic nematodes. Over an exposure period of 48 h to Aphelenchoides besseyi, Bursaphelenchus xylophilus, and Ditylenchus destructor, A. megalosporus (GUCC220044) displayed predation rates of 99.7%, 83.0%, and 21.1%, respectively. A. oligospora (GUCC220045) demonstrated predation rates of 97.3%, 97.3%, and 54.6%, and A. sinensis (GUCC220046) showed rates of 85.1%, 68.3%, and 19.0% against the same cohort of nematodes. The experimental outcomes substantiate that all three identified fungal strains demonstrate predatory activity against the tested nematodes, albeit with varying efficiencies.

Diversity of Fungi Isolated from Potato Nematode Cysts in Guizhou Province, China.

Potatoes rank third in terms of human consumption after rice and wheat. Globodera spp. are significant pests of potato crop worldwide. Globodera rostochiensis was found in Weining County, Guizhou Province, China, in 2019. We collected soil from the rhizosphere zone from infected potato plants and separated mature cysts through simple floatation and sieving methods. The selected cysts were surface-sterilized, and the colonized fungi were isolated and purified. At the same time, the preliminary identification of fungi and fungi parasites on the cysts of nematodes was carried out. This study aimed to define the species and frequency of fungi-colonizing cysts of G. rostochiensis collected from Weining County, Guizhou Province, China, and provide a basis for the control of G. rostochiensis. As a result, 139 strains of colonized fungi were successfully isolated. Multigene analyses showed that these isolates included 11 orders, 17 families, and 23 genera. The genera Fusarium (with a separation frequency of 59%), Penicillium (11%), Edenia (3.6%), and Paraphaeosphaeria (3.6%) were the most frequently occurring. Among the 44 strains, 27 had a colonization rate of 100% on the cysts of G. rostochiensis. Meanwhile, the functional annotation of 23 genera indicated that some fungi have multitrophic lifestyles combining endophytic, pathogenic, and saprophytic behavior. In conclusion, this study showed the species composition and lifestyle diversity of colonized fungi from G. rostochiensis and demonstrated these isolates as potential sources of biocontrol agents. Colonized fungi were isolated from G. rostochiensis for the first time in China, and the taxonomic diversity of fungi from G. rostochiensis was clarified.

Two strains Neocosmosporastercicola (Sordariomycetes, Nectriaceae) with high nematicidal activity, isolated from the cysts of Globodera sp. (Heteroderidae) in China.

Plant-parasitic nematodes (PPNs) are significant pests that result in considerable economic losses in global crop production. Due to the high toxicity of chemical nematicides, there is a need to develop new strategies for nematode control. In this context, nematophagous fungi may offer a viable option for biological control. Two fungal strains (GUCC2212 and GUCC2232) were isolated from cysts of Globodera sp., identified as Neocosmosporastercicola. The fungal filtrates of the strains were evaluated for their nematicidal activity against three species of PPNs: Aphelenchoidesbesseyi, Bursaphelenchusxylophilus and Ditylenchusdestructor. The fermentation filtrates of two strains exhibited substantial toxicity towards the evaluated nematodes, with mortality rates reaching up to 100% within 72 h. Concurrently, N.stercicola also demonstrated predatory and parasitic behavior. The eggs of Globodera sp. were parasitized by the two strains. N.stercicola represents a newly recorded species in China and a novel nematophagous species. In conclusion, the two strains of N.stercicola show promise as biocontrol agents for PPNs management.

A new strain of Volutella citrinella with nematode predation and nematicidal activity, isolated from the cysts of potato cyst nematodes in China.

BACKGROUND: Plant parasitic nematodes (PPNs) are responsible for causing many plant diseases and are extremely difficult to control at present. Currently, due to the negative effects of chemical agents on the environment and human health, the development of new biological pesticides has become an important part of plant nematode control. Nematophagous fungi refers to a class of fungi that kill plant nematodes. Notably, a large number of nematophagous fungi resources remain to be studied. The objective of our study was to use in vitro screening to identify nematophagous fungi and select strains that were highly active against nematodes, providing a primary research for the development and utilization of new nematophagous fungi. RESULTS: A new nematophagous fungal strain (GUCC2219) was isolated from cysts of possibly Globodera spp. and Heterodera spp., identified as Volutella citrinella. The hyphae of V. citrinella produced ring structures of variable size and exhibited predatory and nematicidal activity. The hyphal predation rates (in vitro) against three species of nematodes, Aphelenchoides besseyi, Bursaphelenchus xylophilus, and Ditylenchus destructor, averaged 59.45, 33.35, and 50.95%, respectively, while the fermentation broth produced by the fungus exhibited mortality rates of 100, 100, and 55.63%, respectively, after 72 h. CONCLUSION: V. citrinella is a new strain with nematophagous properties, which are a novel discovery. At the same time, this is the first report of nematicidal and nematode predation activity in the genus Volutella.

New Species-Specific Primers for Molecular Diagnosis of Bactrocera minax and Bactrocera tsuneonis (Diptera: Tephritidae) in China Based on DNA Barcodes.

Tephritidae fruit flies (Diptera: Tephritidae) are regarded as important damage-causing species due to their ability to cause great economic losses in fruit and vegetable crops. Bactrocera minax and Bactrocera tsuneonis are two sibling species of the subgenus Tetradacus of Bactrocera that are distributed across a limited area of China, but have caused serious impacts. They share similar morphological characteristics. These characteristics can only be observed in the female adult individuals. The differences between them cannot be observed in preimaginal stages. Thus, it is difficult to distinguish them in preimaginal stages morphologically. In this study, we used molecular diagnostic methods based on cytochrome c oxidase subunit I and species-specific markers to identify these two species and improve upon the false-positive results of previous species-detection primers. DNA barcode sequences were obtained from 900 individuals of B. minax and 63 individuals of B. tsuneonis. Based on these 658 bp DNA barcode sequences of the cytochrome c oxidase subunit I gene, we successfully designed the species-specific primers for B. minax and B. tsuneonis. The size of the B. minax specific fragment was 422 bp and the size of the B. tsuneonis specific fragment was 456 bp. A series of PCR trials ensured the specificity of these two pairs of primers. Sensitivity assay results demonstrated that the detection limit for the DNA template concentration was 0.1~1 ng/µL for these two species. In this study, we established a more reliable, rapid, and low-cost molecular identification method for all life stages of B. minax and B. tsuneonis. Species-specific PCR can be applied in plant quarantine, monitoring and control of B. minax and B. tsuneonis.

Hippocampal nuclear factor kappa B accounts for stress-induced anxiety behaviors via enhancing neuronal nitric oxide synthase (nNOS)-carboxy-terminal PDZ ligand of nNOS-Dexras1 coupling.

Anxiety disorders are associated with a high social burden worldwide. Recently, increasing evidence suggests that nuclear factor kappa B (NF-κB) has significant implications for psychiatric diseases, including anxiety and depressive disorders. However, the molecular mechanisms underlying the role of NF-κB in stress-induced anxiety behaviors are poorly understood. In this study, we show that chronic mild stress (CMS) and glucocorticoids dramatically increased the expression of NF-κB subunits p50 and p65, phosphorylation and acetylation of p65, and the level of nuclear p65 in vivo and in vitro, implicating activation of NF-κB signaling in chronic stress-induced pathological processes. Using the novelty-suppressed feeding (NSF) and elevated-plus maze (EPM) tests, we found that treatment with pyrrolidine dithiocarbamate (PDTC; intra-hippocampal infusion), an inhibitor of NF-κB, rescued the CMS- or glucocorticoid-induced anxiogenic behaviors in mice. Microinjection of PDTC into the hippocampus reversed CMS-induced up-regulation of neuronal nitric oxide synthase (nNOS), carboxy-terminal PDZ ligand of nNOS (CAPON), and dexamethasone-induced ras protein 1 (Dexras1) and dendritic spine loss of dentate gyrus (DG) granule cells. Moreover, over-expression of CAPON by infusing LV-CAPON-L-GFP into the hippocampus induced nNOS-Dexras1 interaction and anxiety-like behaviors, and inhibition of NF-κB by PDTC reduced the LV-CAPON-L-GFP-induced increases in nNOS-Dexras1 complex and anxiogenic-like effects in mice. These findings indicate that hippocampal NF-κB mediates anxiogenic behaviors, probably via regulating the association of nNOS-CAPON-Dexras1, and uncover a novel approach to the treatment of anxiety disorders.

Sewage treatment by a low energy membrane bioreactor.

A new membrane bioreactor (MBR) was developed for treatment of municipal wastewater. The MBR was mainly made up of an activated sludge reactor and a transverse flow membrane module, with an innovative configuration being in application between them. As a result, the transverse flow membrane module and low recirculation flow rate created advantages, such as lower energy consumption and more resistance to membrane fouling. The total energy consumption in the whole system was tested as 1.97+/-0.74 kWh/m(3) (permeate) while using periodical backwash with treated water and backflush with mixed liquor daily, being in the same level as a submerged membrane bioreactor, reported to be 2.4 kWh/m(3) (permeate). Energy consumption analysis in the system shows that the membrane module was more energy consuming than the other four parts listed as pump, aeration, pipe system and return sludge velocity lose, which consumed 37.66-52.20% of the total energy. The effluent from this system could be considered as qualified for greywater reuse in China, showing its potential application in the future.

Determination and discussion hydraulic retention time in membrane bioreactor system.

Based on the microorganism kinetic model, the formula for computing hydraulic retention time in a membrane bioreactor system (MBR) is derived. With considering HRT as an evaluation index a combinational approach was used to discuss factors which have an effect on MBR. As a result, the influencing factors were listed in order from strength to weakness as: maximum specific removal rate K, saturation constant Ks, maintenance coefficient m, maximum specific growth rate mu m and observed yield coefficient Yobs. Moreover, the formula was simplified, whose parameters were experimentally determined in petrochemical wastewater treatment. The simplified formula is theta = 1.1(1/beta-1) (Ks + S)/KX0, for petrochemical wastewater treatment K and Ks equaled 0.185 and 154.2, respectively.