Phenolic Phytochemicals and Their Antioxidant Activities in Maine-Grown Asian, American-Hybrid, and European Plums

Plum fruits of 16 plum cultivars derived from three species, Asian, American-hybrid, and European plums, and one cultivar of an interspecific hybrid between Asian plum and apricot were investigated to identify and quantify two major groups of phenolic phytochemicals, anthocyanins and hydroxycinnamic acids (HCAs) by HPLC–DAD/MS. The plums were harvested from 2014 to 2017. Some cultivars were analyzed through consecutive years to determine year-to-year differences and to evaluate the maturity impacts on the concentration of anthocyanins and HCAs from the partial-ripe stage and tree-ripe stage. Anthocyanins were present in red−purple colored plums, but their profiles varied among cultivars and species. The two major anthocyanins, cyanidin 3−O−glucoside and cyanidin 3−O−rutinoside were detected in most cultivars, but their concentrations varied depending on the levels of their accumulation in the peel and flesh of the fruits. The total anthocyanin concentration was significantly higher in the tree-ripe stage of plums than in the partial-ripe stage of plums but year-to-year difference in harvest date was not significant. In addition, anthocyanin accumulation in each cultivar was affected by the year-to-year differences in weather condition and crop load, but their specific profiles and the proportion of individual anthocyanins was maintained. Overall, cultivar and maturity differences were dominant in anthocyanin accumulation. Hydroxycinnamic acids (HCAs) also varied among cultivars, but they showed distinguishable concentration differences between species, having significantly higher concentrations in European cultivars than Asian and American cultivars. All cultivars had neochlorogenic acid as a major HCA except the two American-hybrids, ‘Alderman’ and ‘Toka’, in which chlorogenic acid was the major HCA. Unlike anthocyanins, total HCA concentration was not dependent on the year of harvest or maturity at harvest. Total phenolic concentrations (TPC) by the Folin−Ciocalteu method and antioxidant activity (AOA) by the DPPH assay were also measured for three years, from 2015 to 2017. The American-hybrid cultivars displayed greater TPCs than Asian and European cultivars despite having lower concentrations of anthocyanins and moderate concentrations of HCAs. On the contrary, the European cultivars had lower TPCs even though they had higher HCA concentrations than other species. Thus, there was no significant relationship between concentrations of anthocyanins or HCAs and TPCs; however, a curvilinear relationship between TPC and AOA was observed with high coefficients R2=0.89, 0.75, and 0.84 in 2015, 2016, and 2017, respectively. Unlike the linear relationship between TPC and AOA observed in most other studies, the curvilinear relationship found in this study likely results because plums with higher TPC have higher AOA, and AOA was affected more by changes at lower values than at higher TPC values. This suggests that the concentration level of TPC may play a role on AOA in plum extracts

Browntail Moth Research at the University of Maine: A Report of Activities and Findings 2016-2020

The browntail moth has become a very serious problem for many communities in southern, midcoast and central Maine over the past several years as this insect has reached populations levels that we have not seen in 80 to 100 years. Researchers at the University of Maine have teamed up with entomologists in the Maine State Department of Agriculture, Conservation, and Forestry Maine Forest Service (MDACF) to track the spread and investigate the causes of the outbreak and evaluate management strategies for this daunting pest. The report was prepared by Prepared by: Dr. Eleanor Groden, Professor of Entomology, Emerita, School of Biology and Ecology and the Maine Agriculture and Forestry Experiment Station, University of Maine Karla Boyd, M.S. Entomology, Dr. Hye Weon Hwang, PhD Chemistry, Department of Chemistry, University of Maine, Dr. Barbra Cole, Professor of Chemistry, and Dr. Angela Mech, Assistant Professor of Forest Entomolog

Leucine Regulates Zoosporic Germination and Infection by Phytophthora erythroseptica

Pink rot (Phytophthora erythroseptica) of potato is a major concern in many potato production regions. The pathogen produces zoospores that serve as a primary inoculum for infection. To understand how the pink rot incidence is related to pathogen population, qualitative, and quantitative chemical analyses were conducted. It was demonstrated that P. erythroseptica zoospores required a minimal population of 103 zoospores/ml (threshold) for initiating germination and the subsequent infection; the percentage of zoosporic germination was positively correlated with the density of zoospores above the threshold. To elucidate the density-dependent behavior, zoospore exudate (ZE) was extracted from high-density (105/ml) zoospore suspension. Zoosporic inocula of P. erythroseptica at different concentrations were inoculated on potato tubers. Necrotic lesions were caused by inoculum with 100 zoospores per inoculation site; 5 zoospores per site did not cause lesions on the tuber. However, five zoospores did cause lesions when they were placed in ZE, suggesting ZE contained chemical compounds that regulate germination of zoospores. ZE was collected and analyzed using liquid chromatography mass spectroscopy (LC-MS). Results showed that the amino acid leucine was associated with zoosporic germination. Therefore, zoosporic germination and infection of P. erythroseptica were mediated by signaling molecules secreted from zoospores

Multilayer WSe2/MoS2 Heterojunction Phototransistors through Periodically Arrayed Nanopore Structures for Bandgap Engineering

While 2D transition metal dichalcogenides (TMDs) are promising building blocks for various optoelectronic applications, limitations remain for multilayered TMD-based photodetectors: an indirect bandgap and a short carrier lifetime by strongly bound excitons. Accordingly, multilayered TMDs with a direct bandgap and an enhanced carrier lifetime are required for the development of various optoelectronic devices. Here, periodically arrayed nanopore structures (PANS) are proposed for improving the efficiency of multilayered p-WSe2/n-MoS2 phototransistors. Density functional theory calculations as well as photoluminescence and time-resolved photoluminescence measurements are performed to characterize the photodetector figures of merit of multilayered p-WSe2/n-MoS2 heterostructures with PANS. The characteristics of the heterojunction devices with PANS reveal an enhanced responsivity and detectivity measured under 405 nm laser excitation, which at 1.7 × 104 A W−1 and 1.7 × 1013 Jones are almost two orders of magnitude higher than those of pristine devices, 3.6 × 102 A W−1 and 3.6 × 1011 Jones, respectively. Such enhanced optical properties of WSe2/MoS2 heterojunctions with PANS represent a significant step toward next-generation optoelectronic applications. © 2022 Wiley-VCH GmbH1

Cloning of a pore-forming subunit of ATP-sensitive potassium channel from Clonorchis sinensis

A complete cDNA sequence encoding a pore-forming subunit (Kir6.2) of ATP-senstive potassium channel in the adult worm, Clonorchis sinensis, termed CsKir6.2, was isolated from an adult cDNA library. The cDNA contained a single open-reading frame of 333 amino acids, which has a structural motif (a GFG-motif) of the putative pore-forming loop of the Kir6.2. Peculiarly, the CsKir6.2 shows a lack-sequence structure, which deleted 57 amino acids were deleted from its N-terminus. The predicted amino acid sequence revealed a highly conserved sequence as other known other Kir6.2 subunits. The mRNA was weekly expressed in the adult worm

Mycophenolate Mofetil Ameliorates Diabetic Nephropathy in db/db Mice

Chronic low-grade inflammation is an important factor in the pathogenesis of diabetic complication. Mycophenolate mofetil (MMF) has an anti-inflammatory effect, inhibiting lymphocyte proliferation. Previous studies showed attenuation of diabetic nephropathy with MMF, but the underlying mechanisms were unclear. This study aimed to identify the effect of MMF on diabetic nephropathy and investigate its action mechanisms in type 2 diabetic mice model. Eight-week-old db/db and control mice (db/m mice) received vehicle or MMF at a dose of 30 mg/kg/day for 12 weeks. MMF-treated diabetic mice showed decreased albuminuria, attenuated mesangial expansion, and profibrotic mRNA expressions despite the high glucose level. The number of infiltrated CD4+ and CD8+ T cells in the kidney was significantly decreased in MMF-treated db/db mice and it resulted in attenuating elevated intrarenal TNF-α and IL-17. The renal chemokines expression and macrophages infiltration were also attenuated by MMF treatment. The decreased expression of glomerular nephrin and WT1 was recovered with MMF treatment. MMF prevented the progression of diabetic nephropathy in db/db mice independent of glycemic control. These results suggest that the effects of MMF in diabetic nephropathy are mediated by CD4+ T cell regulation and related cytokines

Immunization with RBD-P2 and N protects against SARS-CoV-2 in nonhuman primates

Since the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), various vaccines are being developed, with most vaccine candidates focusing on the viral spike protein. Here, we developed a previously unknown subunit vaccine comprising the receptor binding domain (RBD) of the spike protein fused with the tetanus toxoid epitope P2 (RBD-P2) and tested its efficacy in rodents and nonhuman primates (NHPs). We also investigated whether the SARS-CoV-2 nucleocapsid protein (N) could increase vaccine efficacy. Immunization with N and RBD-P2 (RBDP2/N) + alum increased T cell responses in mice and neutralizing antibody levels in rats compared with those obtained using RBD-P2 + alum. Furthermore, in NHPs, RBD-P2/N + alum induced slightly faster SARS-CoV-2 clearance than that induced by RBD-P2 + alum, albeit without statistical significance. Our study supports further development of RBD-P2 as a vaccine candidate against SARS-CoV-2. Also, it provides insights regarding the use of N in protein-based vaccines against SARS-CoV-2.Y