An accurate, efficient, and economical identification technology for black twig borer based on species-specific cytochrome C oxidase subunit I PCR assay.

Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae, Scolytinae) is a worldwide invasive species that causes huge economic loss and environmental damage in many countries. Traditional morphological characteristics make it hard to identify scolytines due to their tiny size. Besides, the intercepted insect samples are incomplete, and the limitation of insect (larvae and pupae) morphology makes morphological identification more difficult. The majority of the damage is caused by adults and fungi that serve as nutrition for their larvae. They destroy plant trunks, branches, and twigs, affecting plant transport tissues in both weak and healthy plants. An accurate, efficient, and economical molecular identification technique for X. compactus not restricted by professional taxonomic knowledge is necessary. In the present study, a molecular identification tool based on the mitochondrial DNA gene, cytochrome C oxidase subunit I (COI) was developed. A species-specific COI (SS-COI) PCR assay was designed to identify X. compactus regardless of the developmental stage. Twelve scolytines commonly found in eastern China, namely Xylosandrus compactus, X. crassiusculus, X. discolor, X. germanus, X. borealis, X. amputates, X. eupatorii, X. mancus, Xyleborinus saxesenii, Euwallacea interjectus, E. fornicatus, and Acanthotomicus suncei, were included in the study. Additionally, specimens of X. compactus from 17 different areas in China, as well as a specimen collected from the United Stated, were also analyzed. Results demonstrated the accuracy and high efficiency of the assay, regardless of the developmental stage or the type of specimen. These features provide a good application prospect for fundamental departments and can be used to prevent the harmful consequences of the spread of X. compactus.

First report of southern blight caused by Athelia rolfsii on Spotted laurel (Aucuba japonica) in China.

Aucuba japonica, also known as spotted laurel, is a woody, broadleaf, evergreen shrub with variegated leaves in the Garryaceae family, widely used in urban parks, green spaces and landscaping. In October 2019, an outbreak of a disease with southern blight symptoms was observed on A. japonica planted as a green barrier in Kunshan city, Jiangsu province of China (N31°32'37", E120°00'41"). The disease incidence was estimated up to 30%. The infected plants showed symptoms including brown to black necrotic stems, white mycelium and white to dark reddish brown sclerotia at the base of the stem and decayed tissues. Fifteen samples (10 sclerotia and 5 mycelial fragments) were collected from symptomatic plants for causal agent isolation. The sclerotia were disinfected with 70% ethanol for 2 to 3 s and 5% NaClO for 2 min, rinsed three times with sterile water, then cultivated on potato dextrose agar (PDA) plate at 25°C. Mycelial fragments were transferred to PDA plates by an inoculation needle directly. In total 15 fungal strains were obtained and purified by transferring single hyphal tips to fresh media. All the strains showed consistent phenotype, white mycelia on PDA, with an average growth rate of 13.6 to 16.9 mm/day (n=30), and mycelia with clamp connections were observed under the microscope. Globose sclerotia formed at 4 days post inoculation (dpi), initially whitish, turning to beige and eventually dark reddish brown. The number of sclerotia produced per plate ranged from 280 to 486 (mean = 378; n = 30), and the diameter of mature sclerotia ranged from 0.8- to 1.6-mm (mean = 1.24; n = 150). Three strains YKY2020.02, YKY2020.03, and YKY2020.07 were selected for further molecular identification. Genomic DNA was extracted from these strains using a CTAB method (Mahadevakumar et al. 2018). ITS primer pair ITS1/ITS4 was used to amplify the internal transcribed spacer region (White et al. 1990). PCR products were then sequenced by Sangon Biotech (Shanghai, China), and subsequently, the ITS sequences (686 bp) were deposited in GenBank under accession number OM647806, OP279917 and OP279918, respectively. All sequences showed 99-100% similarity with Athelia rolfsii sequences from GenBank by BLAST analysis in NCBI. The phylogenetic tree of ITS sequences generated by the neighbor-joining analysis in MEGA-X also shows that all selected strains clustered with different strains of A. rolfsii into one big branch, indicating that these strains are the same. Based on morphological and molecular characteristics, these strains were identified as A. rolfsii (Curzi) C.C. Tu & Kimbr. (syn. Sclerotium rolfsii) (Stevens 1931; Paul et al. 2017). Pathogenicity tests were conducted on healthy plants of A. japonica (n = 15). Five-day-old mycelial discs (5 mm) were inoculated at the basal part of the plants with mycelial side inward and secured with wet absorbent cotton, while plants inoculated with sterile water were used as a control (n = 5). All plants were kept in a greenhouse with a temperature of 26 to 33°C and an average relative humidity higher than 65%. At 5 dpi, all inoculated plants showed symptoms similar to those observed in fields. Control plants remained asymptomatic. To fulfill Koch's postulates, identities of all the causal pathogens were confirmed by reisolation in PDA and identification by morphology. To our knowledge, this is the first report of A. rolfsii causing southern blight on A. japonica worldwide. Our findings are important for future disease control strategy development.

Condensate Oil-Tolerant Foams Stabilized by an Anionic-Sulfobetaine Surfactant Mixture.

Foams are widely used to remove liquid loading at the bottom of gas wells to improve natural gas production. However, it becomes ineffective when a gas well contains a large amount of hydrocarbon condensate because oil will rupture the foams. In this work, condensate oil-tolerant foams were developed and stabilized by a mixture of cocamidopropyl hydroxyl sulfobetaine (CHSB) and sodium dodecyl sulfate (SDS). The foam properties are examined at different temperatures under atmospheric conditions and high pressures with various contents of condensate oil. It is found that the foam stability is improved when the oil content is increased; in addition, high temperature, high salinity, and high pressure are beneficial for foam stabilizing. To reveal the mechanism of stable foam in the presence of high content of oil, a confocal microscope was employed to visualize oil-foam interactions. It was observed that the high stability of the SDS-CHSB foams is ascribed to the formation of stable pseudoemulsion between oil droplets and the gas-liquid interface. Such condensate oil-tolerant foams show promising potential to be used in the foam-assisted lift process during natural gas production.

CO2-switchable foams stabilized by a long-chain viscoelastic surfactant.

Smart foams sensitive to external stimulation have gained increasing attention recently. However, reversibly switchable CO2 foams have been less documented. In this work, a novel kind of CO2-switchable foams was developed using a long-chain cationic surfactant, N-erucamidopropyl-N,N-dimethylammonium bicarbonate (UC22AMPM⋅H+), as both the foaming agent and stabilizer. The foams can be rapidly transformed between stable and unstable states at ambient temperature with CO2/NH3·H2O as the triggers. The foaming properties and switchable performance were examined by a combination of confocal microscopy, cryogenic transmission electron microscopy, and rheological techniques. The results demonstrated that the enhanced foam stability in the presence of CO2 is attributed to the high bulk phase viscosity and gas/liquid surface viscosity, resulting from the entanglement of wormlike micelles (WLMs) formed from UC22AMPM⋅H+. When NH3·H2O is added, the network structure of WLMs is disrupted, and the bulk phase viscosity and surface viscosity subsequently drop, consequently leading to an ultimate foam destabilization. Such a CO2-sensitive viscoelastic surfactant could not only be used to fabricate smart CO2 foams but can also enable CO2 to play dual roles as both the dispersed phase, as most gases do, and an "activator" to protonate long-chain tertiary surfactants into cationic analogs to form viscoelastic WLMs to stabilize foams.

Diagnostic performance of noninvasive fractional flow reserve derived from coronary computed tomography angiography in ischemia-causing coronary stenosis: a meta-analysis.

PURPOSE: Fractional flow reserve based on coronary computed tomographic angiography (CCTA; FFRCT) can evaluate functional severity in coronary artery disease (CAD). This study investigated the diagnostic value of FFRCT for determining CAD severity. MATERIALS AND METHODS: Medline, Cochrane, EMBASE, and Google Scholar databases were searched until June 16, 2016 using the following search terms: fractional flow reserve, coronary computed tomography angiography, myocardial ischemia. Randomized controlled trials, two-arm prospective studies, and retrospective studies were included in the analysis. RESULTS: Twenty-one studies were included with a total of 2216 subjects and 2798 vessels. FFRCT, sensitivity per-vessel and per-patient were ≥82% and specificity was ≥73% for diagnosis of ischemia. FFRCT had better diagnostic accuracy and discrimination than CCTA. CONCLUSION: This study indicates that FFRCT may be a good tool for screening and diagnosing of myocardial ischemia in patients with CAD.