Dwiroopa punicae Causing Leaf Spot Disease on Pomegranate in Guizhou, China.

Punica granatum 'Tunisia' is widely planted in several areas of Kaiyang County, Guizhou Province, China. Symptoms of leaf spot and fruit rot were observed in April 2020. Infected pomegranate leaves exhibited scattered, oval, yellow-to-brown spots (2-5 mm), and numerous melanized pycnidia were observed in the center of the lesions. All 7-year-old pomegranate trees in a private orchard (Shangyi orchard, E27°09'08", N107°10'58"), exhibited the same symptoms, and 25% of the diseased pomegranate trees had blighted leaves in the late stage. Eighty diseased P. granatum leaves were collected in the orchard. Abundant fruiting bodies were observed on the surface of diseased spots examined using a dissecting microscope. Portions of the symptomatic leaves were surface disinfected with 75% ethanol for 30 s and then in 2% NaClO for 1 min, rinsed three times with sterile distilled water, and transferred onto potato dextrose agar (PDA) at 28°C for 3 weeks. The morphological characteristics of potential pathogens were observed and photographed under a compound light microscope (Zeiss Scope 5) equipped with an AxioCam 208 color camera. Pycnidial conidiomata were erumpent, globose, black, with a central ostiole, and oozed a slimy black conidial mass. Conidiophores were reduced to conidiogenous cells, ampulliform to subcylindrical, hyaline to pale brown, and proliferated percurrently at the apex. Macroconidia were solitary, one-celled, obovoid, truncate at the base, rounded at the apex, dark brown, aseptate, granular, and thick-walled, (11.0-)12.8-18.2(-19.0) × (9.2-)10.0-15.1(-16.0) µm (av: 14.8 × 12.0 µm, n = 30). No meso- or microconidia were observed. In morphology, our fungi were very similar to Dwiroopa punicae K.V. Xavier, A.N. Kc, J.Z. Groenew, Vallad & Crous (Xavier et al., 2019). Primers ITS4 and ITS5 were used to amplify the ITS, LROR and LR5 were for the LSU (White et al. 1900), and fRPB2-5F and fRPB2-7cR for rpb2 (Liu et al. 1999). Phylogenetic analysis based on these three loci also suggested that our strain was D. punicae, since there were 100% match for ITS and LSU and only two base differences in rpb2 gene between our strain and the D. punicae (CBS 143163). The qualified sequences were submitted to GenBank (ITS: MZ816695, MZ816696, MZ816697; LSU: MZ816692, MZ816693, MZ816694; rpb2: MZ802953). To fulfill Koch's postulates, mycelial plugs (5 mm diameter) were used for an inoculation experiment, only because the fungal isolates failed to produce conidia on PDA, and conidia from diseased tissues were also fewer to make the required spore suspension. A total of 20 attached leaves were used from three pots of pomegranate seedlings in the artificial climate chamber (25°C). Each mycelial plugs cut from 1-week-old PDA cultures were placed on one healthy leaf wrapped with a plastic fresh-keeping film. As control, leaves were inoculated with sterile PDA plugs. After 24h, the plugs were removed. The inoculation experiment was performed three times. Symptoms similar to the original were observed at the 7th day after inoculation on all inoculated plant leaves and necrosis occurred in 30-50% of leaf tissue, but control plants remained healthy. Dwiroopa punicae was successfully re-isolated from the inoculated diseased tissues after morphological and phylogenetic analyses. To the best of our knowledge, this is the first report of D. punicae causing leaf spot disease on pomegranate trees in China. This first report of D. punicae in China provides a basis for the diagnosticians and researchers to identify the disease and formulate disease management strategies.

UV-irradiation induced biological activity and antibacterial activity of ZnO coated magnesium alloy.

In order to improve the biological activity and antibacterial activity of magnesium alloy, the single zinc oxide (ZnO) coating was prepared on magnesium alloys using microwave aqueous synthesis method and followed heat treatment. Then, the coated magnesium alloys were irradiated with ultraviolet (UV) light for different time and subsequently immersed in simulated body fluids (SBF). The influences of UV-irradiated time on the morphology, composition, in vitro biological activity and antibacterial activity were investigated. The results indicated that the ability of the apatite formation on the ZnO coated magnesium alloys surface was significantly enhanced as UV irradiation time prolonged, and the bone-like apatite was formed after UV irradiation for 24 h and then immersing into SBF for 2 weeks, the newly formed apatite was dense and integrate, implying that UV irradiation could activate ZnO coating to improve the biological activity. Moreover, after immersing in SBF for 2 weeks, the antibacterial experiment results demonstrated that ZnO coated magnesium alloys with UV irradiation time of 24 h exhibited more effective antibacterial activity than those of naked magnesium alloys and ZnO coated magnesium alloys which were not irradiated by ultraviolet (UV) light. This work afforded a surface strategy for designing magnesium alloy implant with desirable osseointegration ability and antibacterial property simultaneously for orthopedic and dental applications.

Ultrasonic aqueous synthesis of corrosion resistant hydroxyapatite coating on magnesium alloys for the application of long-term implant.

For the orthopedic application, the promising biodegradable magnesium alloys gained increasing attention. In order to improve the interface bonding strength and corrosion resistance of magnesium alloys, a novel ultrasonic aqueous synthesis approach was performed to produce hydroxyapatite coating on biodegradable magnesium alloys. The effect of ultrasonic time on the composition, microstructure, interface bonding strength and corrosion resistance of HA coated magnesium alloys were investigated. A dense and crack-free HA coating was synthesized by only ultrasonic cavitation for 1 h in the aqueous solution containing Ca2+ and PO43- ions and the coating was constituted of bamboo leaf-like HA staggered irregularly, which endowed magnesium alloy with a sufficient interface bonding strength of 18.1 ±â€¯2.2 MPa. The electrochemical performance and mineralization ability of the coated magnesium alloys were carried out in the simulated body fluids. Compared with bare magnesium samples, the coated samples presented excellent corrosion resistance and could rapidly induce apatite formation after only three days of immersion in the simulated body fluid (SBF). Moreover, in the immersion test of 90 days, HA coatings could provide a long-term protection for magnesium alloy substrate, indicating that ultrasonic aqueous synthesized HA coating could be acted as a promising modified biomaterial on magnesium alloys for the orthopedic application.

Effects of gas produced by degradation of Mg-Zn-Zr Alloy on cancellous bone tissue.

Mg-Zn-Zr alloy cylinders were implanted into the femoral condyles of Japanese big-ear white rabbits. X-ray showed that by 12 weeks following implantation the implant became obscure, around which the low-density area appeared and enlarged. By 24 weeks, the implant was more obscure and the density of the surrounding cancellous bone increased. Scanning electron microscopy examination showed bone tissue on the surface of the alloy attached by living fibers at 12 weeks. Micro-CT confirmed that new bone tissue on the surface of the residual alloy implant increased from 12 weeks to 24 weeks. By 12 weeks, many cavities in the cancellous bone tissue around the implant were noted with a CT value, similar to gas value, and increasing by 24 weeks (P<0.01). Histological examination of hard tissue slices showed that bone tissue was visibly attached to the alloy in the femoral condyle at 12 weeks. The trabecular bone tissues became more intact and dense, and the cavities were filled with soft tissue at 24 weeks. In general, gas produced by the degradation of the Mg-Zn-Zr alloy can cause cavitation within cancellous bone, which does not affect osteogenesis of Mg alloy.

C60/N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine:MoO3 as the interconnection layer for high efficient tandem blue fluorescent organic light-emitting diodes.

The high efficient tandem blue fluorescent organic light emitting diodes (OLEDs) with the transparent interconnection layer (ICL) of fullerence (C60)/Molybdenum oxide (MoO3)-doped N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB) were presented. A stack consisting of 0.5 nm of LiF and 1 nm of Ca, which is located from C60 to adjacent electron transporting layer is used as an electron injection layer. The experiment results indicate that the luminance of the tandem device is basically equal to that of the traditional single-unit device, but the current density of the tandem device is much less than that of the single-unit device under a same luminance. The current efficiency and the maximal power efficiency of tandem device with LiF/Ca/C60/NPB:MoO3/MoO3-based interconnection layer have been approximately enhanced by 250% and 126%, respectively. In addition, we also analyze that the mechanism of the efficiency enhancement is ascribed to the effective charge separation and transport of the ICL in tandem OLEDs.

In vivo comparative property study of the bioactivity of coated Mg-3Zn-0.8Zr alloy.

In this in vivo study, degradable Mg-3Zn-0.8Zr cylinders were coated with a calcium phosphorus compound (Ca-P) layer or a magnesium fluoride (MgF2) layer; uncoated Mg-3Zn-0.8Zr alloy was used as a control. These were then implanted intramedullary into the femora of nine Japanese big-ear white rabbits for implantation periods of 1, 2 and 3 months. During the postoperative observation period with radiographic examination, the results showed that the MgF2-coated implants were tolerated well compared to the Ca-P-coated implants and uncoated implants. Moreover, large amounts of cells, rich fibrillar collagen and calcium and phosphorus products were found on the surface of the MgF2-coated implants using scanning electron microscopy. Micro-computed tomography further showed a slight decrease in volume (23.85%) and a greater increase in new bone mass (new bone volume fraction=11.56%, tissue mineral density=248.81 mg/cm(3)) for the MgF2-coated implants in comparison to uncoated and Ca-P compound-coated implants after 3 months of implantation.