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Orthorhombic olivine-structured LiMSiO 4 (M = Ho, In) ceramics were synthesised using the solid-state reaction. Promising microwave dielectric properties of ε r = 10.04, τ f = 23.3 ppm/°C and a high-quality factor (Q × f) of 11,415 GHz for LiHoSiO 4 were obtained at 1050 °C, and ε r = 7.78, τ f = −46.8 ppm/°C and Q × f = 23,390 GHz for LiInSiO 4 were achieved at 1140 °C. According to the bond valence result, Ho3+ presented a slightly compressed state but Li+ and Si4+ exhibited a strong rattling state in LiHoSiO 4 , which led to higher ε r than the ε theo. The integrated effect of rattling cations (Li+ and In3+) and a compressed cation (Si4+) in LiInSiO 4 resulted in a small positive deviation Δ ε r. The larger packing fraction of LiInSiO 4 contributed to a higher Q × f than LiHoSiO 4. The Si–O bond in both ceramics played a leading role in influencing the Q × f according to the Phillips−Van Vechten−Levine chemical bond theory. [ABSTRACT FROM AUTHOR]

Allamanda cathartica is an ornamental medicinal plant that grows widely in the tropics. In the present study, two novel viruses, Allamanda chlorotic virus A (AlCVA) and Allamanda chlorotic virus B (AlCVB), were identified in an A. cathartica plant with interveinal chlorosis by ribosomal RNA-depleted total-RNA sequencing. Phylogenetic analysis and sequence comparisons confirmed that AlCVA and AlCVB belong to the families Closteroviridae and Betaflexiviridae, respectively. Long, flexuous, filamentous virus particles approximately 12 nm in diameter and 784-2291 nm in length were observed using transmission electron microscopy. A specific RT-PCR assay was used to demonstrate a consistent association of viral infection with symptoms. [ABSTRACT FROM AUTHOR]

The cucurbit vegetable chieh-qua (Benincasa hispida var. chieh-qua How) is an important crop in South China and southeast Asian countries. Viral diseases cause substantial loss of chieh-qua yield. To identify the viruses that affect chieh-qua in China, ribosomal RNA-depleted total RNA sequencing was performed using chieh-qua leaf samples with typical viral symptoms. The virome of chieh-qua comprises four known viruses (melon yellow spot virus (MYSV), cucurbit chlorotic yellows virus (CCYV), papaya ringspot virus (PRSV) and watermelon silver mottle virus (WSMoV) and two novel viruses: cucurbit chlorotic virus (CuCV) in the genus Crinivirus and chieh-qua endornavirus (CqEV) in the genus Alphaendornavirus. The complete genomes of the two novel viruses in chieh-qua and three other isolates of CuCV in pumpkin, watermelon and cucumber were determined and the recombination signals of pumpkin and watermelon isolates of CuCV were detected. A reverse transcriptase PCR indicated that the dominant viruses of chieh-qua in Hainan are MYSV (66.67%) and CCYV (55.56%), followed by CuCV (27.41%), WSMoV (7.41%), cucumber mosaic virus (8.15%), zucchini yellow mosaic virus (6.67%), PRSV (6.67%) and CqEV (35.56%). Our findings support diagnostic and prevalence studies of viruses infecting chieh-qua in China, enabling sustainable control strategies for cucurbit viruses worldwide. [ABSTRACT FROM AUTHOR]

The viromic profile of Polyscias balfouriana cv. Marginata, a perennial woody and ornamental plant, was determined using ribosomal RNA-depleted total RNA (rRNA-depleted totRNA) sequencing. Five viruses (i.e., polyscias mosaic virus, PoMV; one potential novel rhabdovirus; and three novel viruses of Betaflexiviridae and Closteroviridae) were detected and prevalence-surveyed in Hainan province, China. The genomes of polyscias capillovirus 1 (PCaV-1) and polyscias citrivirus 1 (PCiV-1) of family Betaflexiviridae were completed, and the genomes of polyscias crinivirus 1 (PCrV-1) of Closteroviridae were nearly completed lacking the 5′ and 3′ termini. PCaV-1 shares 68% genome nucleotide (nt) identity and 66% replicase (Rep) amino acid (aa) identity with homologues in apple stem grooving virus (ASGV). PCiV-1 shares 65% genome nt identity and 64% Rep aa identity with homologs in citrus leaf blotch virus (CLBV). Meeting the species demarcation criteria, PCaV-1 and PCiV-1 were considered to be new species in genera Capillovirus and Citrivirus, respectively. PCrV-1 shares high genome nt identity (62%), heat shock protein 70-like protein (HSP70h) and RNA-dependent RNA polymerase (RdRp) aa identity (78–80%) with homologues in tomato chlorosis virus (ToCV). We tentatively consider PCrV-1 to be an unclassified member of the Crinivirus genus. PoMV, PCaV-1, PCiV-1, and PCrV-1 are the prevalent viruses with >73% occurrence in the Xinglong Tropical Botanical Garden, Hainan, China. [ABSTRACT FROM AUTHOR]

Black pepper (Piper nigrum L.) is one of the most ancient spice crops in the world. Hainan Province is the largest black pepper‐producing region in China. Viral disease is one of the main factors affecting black pepper. However, there are rarely studies on black pepper viral disease in China. We performed a survey in five major black pepper‐growing counties (Qionghai, Wenchang, Wanning, Haikou and Ding'an) of Hainan Province and collected 589 samples, with virus‐like symptoms from 2014 to 2019. Various viruses were identified including cucumber mosaic virus (CMV), piper yellow mottle virus (PYMoV), Piper DNA virus 1 (PDV‐1) and Piper DNA virus 2 (PDV‐2) using small RNA deep sequencing. The RT‐PCR screening of field samples indicated three types of infection: CMV alone (5.56%), PYMoV + PDV‐1 + PDV‐2 (25.00%) and PYMoV + CMV +PDV‐1 + PDV‐2 (69.44%). The data suggested that PYMoV might be the main pathogen causing virus diseases of black pepper. Two complete genome sequences of PYMoV were obtained. Phylogenetic analysis showed that PYMoV isolates from China were placed in a branch distinct from PYMoV isolates from India. To our knowledge, this is the first report of PYMoV, PDV‐1 and PDV‐2 naturally infecting black pepper, and the first genome sequence of PYMoV in China. [ABSTRACT FROM AUTHOR]

Abstract: A number of 8-substituted chrysin analogs have been prepared and evaluated for their inhibitory activities of cyclooxygenase-2 catalyzed prostaglandin E2 and iNOS-mediated NO production. Analogs were prepared via Suzuki–Miyaura C–C cross coupling reaction of 8-iodo-5,7-dimethoxyflavone and alkyl/areneboronic acids as a key reaction. Among the analogs tested, 5,7-dihydroxy-8-(pyridine-4-yl)flavone (3d) showed strong biological activities against COX-2 catalyzed PGE2 and iNOS-mediated NO production from LPS-induced RAW 264.7 cells compared to those of chrysin. [Copyright &y& Elsevier]

In July 2008, Stylosanthes guianensis with witches'-broom symptoms and Stylosanthes capitata with yellows symptoms were observed in Hainan Province, China. From the symptomatic S. guianensis, the phytoplasma-specific 16S rRNA gene fragment of 1.4 kb was amplified by a direct PCR, and a fragment of 16S rRNA gene of 1.2 kb was obtained from the symptomatic Stylosanthes capitata by a nested PCR. Sequencing results and NCBI BLASTn analysis showed that the two phytoplasmas belonged to group 16SrII. Polygenetic analysis and virtual RFLP classified the two phytoplasmas into subgroup 16SrII-A. [ABSTRACT FROM AUTHOR]

Abstract: A series of 1,5-diarylimidazoles with 4-methylsulfonylphenyl group were prepared and evaluated for the inhibitory activities against COX-2 catalyzed PGE2 production from LPS-induced RAW 264.7 cells. Most of synthesized 1,5-diarylimidazoles exhibited strong inhibitory activities regardless of the position of the 4-methylsulfonylphenyl group. The 1,5-diarylimidazoles with a halogen atom (3c–3h, 3n–3p) gave mostly excellent inhibitory activities regardless of the position and species of the halogen atom. Whereas the 1,5-diarylimidazoles with two fluorine atoms (3k, 3l, 3r, 3s) showed rather reduced inhibitory activities. [Copyright &y& Elsevier]

Abstract: In order to establish anti-inflammatory potential of biflavonoids, 17 biflavone derivatives having a 6-O-7″ linkage were synthesized and their effects on cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were evaluated. The basic molecule (6-O-7″ biflavone) potently inhibited COX-2-mediated PGE2 production (IC50: <2μM), being less active on iNOS-mediated NO production (IC50: >50μM) from lipopolysaccharide-treated RAW 264.7 cells, a mouse macrophage cell line. Generally, the hydroxyl/methoxyl substitution(s) on the basic biflavone (6-O-7″) reduced the inhibitory activity of PGE2 production, while the effects on NO production were varied. It is suggested that the basic biflavone (6-O-7″) may have a potential for new anti-inflammatory agent. [Copyright &y& Elsevier]

Areca palm, rubber tree, and coffee are always planted adjacent to each other or intercropped with each other, and Colletotrichum siamense was found to be the dominant species of Colletotrichum from these crops in Hainan, China. To study the population structure, pathogenicity, and fungicide sensitivity of C. siamense from these three crops in Hainan, isolates were first identified by their morphological characteristics and multilocus phylogeny. Then both permutational multivariate analysis of variance (PERMANOVA) and pairwise FST analysis showed that the original host and geographical origin (counties) had significant effects on genetic variation in the C. siamense population, explaining 5.6% and 16.3% of genetic variation, respectively. There were significant genetic differentiations between coffee and rubber tree populations but the genetic differentiation was small (FST = 0.04), while significant differentiations were observed among all populations from different counties except those between Haikou and Chengmai. Pathogenicity analysis using artificial inoculation showed that isolates had significantly higher disease incidence and diseased lesion diameter on wounded leaves than on nonwounded leaves. However, the original host of an isolate and geographical origin did not significantly affect the pathogenicity of the C. siamense populations from these three hosts. In vitro tests showed that there were no significant differences in the sensitivity of C. siamense populations to carbendazim, prochloraz, difenoconazole, and propiconazole from different original hosts and geographical origins. The present study suggests that host specialization of C. siamense has not occurred yet in coffee, rubber tree, and areca palm. [ABSTRACT FROM AUTHOR]

Powdery mildew is an important disease of rubber trees worldwide. To assess the effects of temperature and leaf age on conidial germination and disease development, conidia were inoculated onto rubber tree seedlings with leaves at three phenological stages (copper bronze, colour‐changing, and light green) and then incubated at six constant temperatures (10, 15, 20, 25, 30, and 35°C). Leaf age did not affect conidial germination (p =.296) whilst temperature did (p <.0001), although conidia were able to germinate at all tested temperatures. The estimated optimal temperature for conidial germination was 23.2°C. Leaf age, temperature, and their interactions had significant effects on conidial infection and hypha number (p <.0001). At 10 and 35°C, more than 2 and 4 days were needed for infection to complete, respectively, compared to <2, 1, 0.5, and 0.5 days for 15, 20, 25, and 35°C, respectively. Sporulation and mildew symptoms were only observed on those inoculated leaves of all stages at 20 and 25°C, and at the copper bronze stage only at 15°C. The latent period on the copper bronze leaves at 15°C was longer (9 days) than at 20 and 25°C (4 days). The latent period at 20 and 25°C increased from 4 to 7 days as the leaf development stage increased from copper bronze to light green. Therefore, temperature affected germination and postgermination growth of rubber tree powdery mildew, whereas leaf age primarily affected postgermination growth of the pathogen. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the status of weed Solanum nigrum L. as a transitional host for Meloidogyne enterolobii and its effect on the population base of the nematodes in the next season. The nematode species infecting S. nigrum L. in a fallow field was identified by morphological identification and molecular diagnosis, and parasitic characteristics of the nematodes in S. nigrum L., including development of the nematode in S. nigrum L., the histopathological response of S. nigrum L. to M. enterolobii, and the host suitability of S. nigrum L., were studied. The M. enterolobii soil population density was evaluated before and after S. nigrum L. planting. Species identification revealed that it was M. enterolobii infection. Developmental observation indicated that juveniles of M. enterolobii developed fast in S. nigrum L., establishing feeding sites by 5 days after inoculation (DAI) and forming obvious egg masses on the root at 25 DAI. Histopathological observation showed the typical susceptible response of S. nigrum L., including giant cells with thick cell walls, uniformly dense cytoplasm, and less vacuolation, mainly inside the vascular cylinder. Host suitability assays suggested that S. nigrum L. is a good host for M. enterolobii with an average reproduction factor (RF) of 48.04 ± 14.71. Population densities assays revealed that S. nigrum L. increased the population density of M. enterolobii for two consecutive years from 0.48 ± 0.25 and 0.53 ± 0.31 J2/cm3 to 1.33 ± 0.16 and 1.56 ± 0.43 J2/cm3 of soil. These results indicated that M. enterolobii could reproduce well by infecting S. nigrum L. during the fallow season, and it increased the population base of M. enterolobii to the next season during vegetable production, which suggested a novel direction for the control of root-knot nematodes by controlling weeds as transitional hosts of M. enterolobii in the fallow season. [ABSTRACT FROM AUTHOR]

Abstract: A number of oroxylin A analogs were prepared and evaluated for their inhibitory activities against iNOS-mediated nitric oxide (NO) production from LPS-stimulated BV2 cells. The analogs were synthesized from purchased 2′-hydroxy-4,5,6-trimethoxyacetophenone and aldehydes in 3 steps. Among the tested compounds, several analogs (3b, 3c, 3d, 3f) exhibited strong inhibitory activities. Especially, the analog with 4-nitrophenyl group (3b) showed stronger inhibitory activity (IC50 =4.73μM) than that of wogonin (IC50 =7.80μM). [Copyright &y& Elsevier]

A disease on parthenium weed ( Parthenium hysterophorus L.) was observed in June 2008 in Danzhou of Hainan Province. Infected weeds showed phytoplasma-like associated symptoms such as severe stunting, excessive proliferation of shoots, inflorescence-clustering, green petal, small leaves and witches'-broom. The original cause of phytoplasma was further confirmed by polymerase chain reaction (PCR). PCR products of 1.8 kb were obtained using the universal primers pair (P1/P7) designed to amplify the entire 16S rDNA and the 16/23S intergenic spacer region in a direct PCR assay. The primers pair R16F2n/R2 was used to amplify a PCR product of 1.2 kb. Restriction fragment length polymorphism (RFLP) was used to analyze the partial 16S rDNA sequences (1.2 kb) of all phytoplasma DNA digested with five endonucleases ( Kpn I, Hpa II, Taq I, Rsa I, EcoR I). The RFLP patterns of the strain were found to be identical with that of the reference peanut witches'-broom phytoplasma. Based on the RFLP data, it is suggested that the phytoplasma strain belongs to subgroup 16SrII-A. This is the first demonstration of a 16SrII-A group phytoplasma associated with parthenium weed. [ABSTRACT FROM AUTHOR]

Recent studies reported that the level of PD-L1 carried by extracellular vesicles (EVs) could distinguish the presence of tumors and had a good correlation with the response to immunotherapy. In this manuscript, we developed an EV-TdT assay for isolation and detection of PD-L1+ EVs. PD-L1+ EVs were directly captured from biological samples by PD-L1 antibodies immobilized on the magnetic beads (MBs), then combined with cholesterol modified DNA probes, which initiated the terminal deoxynucleotidyl transferase (TdT) to amplify the signal of PD-L1+ EVs. The EV-TdT assay enables selective enrichment of PD-L1+ EVs in low-content samples, such as blood and excreta of small amounts of primary tumor cells. Moreover, it can evaluate the relative abundance of PD-L1+ EVs in the total population, by this way, we observed that PD-L1+ EVs were more abundant in the extracellular microenvironment of primary tumor cells than in human plasma, indicating that quite a bit of PD-L1+ EVs were derived from tumor cells. The EV-TdT assay has been proven a practical method for detection of PD-L1+ EVs and is greatly potential as an alternative to existing assays for screening immunotherapy benefit populations. [ABSTRACT FROM AUTHOR]