Spatial patterns,ecological niches,and interspecific competition of avian brood parasites: inferring from a case study of Korea

Since obligate avian brood parasites depend completely on the effort of other host species for rearing their progeny, the availability of hosts will be a critical resource for their life history. Circumstantial evidence suggests that intense competition for host species may exist not only within but also between species. So far, however, few studies have demonstrated whether the interspecific competition really occurs in the system of avian brood parasitism and how the nature of brood parasitism is related to their niche evolution. Using the occurrence data of five avian brood parasites from two sources of nationwide bird surveys in South Korea and publically available environmental/climatic data, we identified their distribution patterns and ecological niches, and applied species distribution modeling to infer the effect of interspecific competition on their spatial distribution. We found that the distribution patterns of five avian brood parasites could be characterized by altitude and climatic conditions, but overall their spatial ranges and ecological niches extensively overlapped with each other. We also found that the predicted distribution areas of each species were generally comparable to the realized distribution areas, and the numbers of individuals in areas where multiple species were predicted to coexist showed positive relationships among species. In conclusion, despite following different coevolutionary trajectories to adapt to their respect host species, five species of avian brood parasites breeding in South Korea occupied broadly similar ecological niches, implying that they tend to conserve ancestral preferences for ecological conditions. Furthermore, our results indicated that contrary to expectation interspecific competition for host availability between avian brood parasites seemed to be trivial, and thus, play little role in shaping their spatial distributions and ecological niches. Future studies, including the complete ranges of avian brood parasites and ecological niches of host species, will be worthwhile to further elucidate these issues.     

Pigment and isozyme variation in aspen shoots regenerated from callus culture

Pigment as well as isozyme variations were observed among aspen (Populus tremuloides Michx.) plants regenerated from callus cultures. Out of more than 600 plantlets, two chimeric plants (one with green base and two albino shoots and the other with an albino shoot) were produced. Callus derived from albino shoots produced albino as well as chimeric plants when transferred to shoot inducing medium. Isozyme patterns of 119 plants were examined by starch gel electrophoresis. Thirty plants showed variation in shikimic dehydrogenase isozyme and 41 in isocitric dehydrogenase. Variation was also observed in malate dehydrogenase and phosphoglucose isomerase. No variation was seen in 6-phosphogluconate dehydrogenase. Pigment variation was not associated with any isozyme changes.Abbreviations BA 6-benzyladenine - IBA indole-3-butyric acid - GD Gresshoff & Doy medium - WPM woody plant medium - SKD shikimic dehydrogenase - IDH isocitric dehydrogenase - MDH malate dehydrogenase - PGI phosphoglucose isomerase - 6-PGD 6-phosphogluconate dehydrogenase     

Thyroid microsomal antigen in Graves' thyroid is not different from that in normal thyroid.

Differences from normal in microsomal antigen (M-Ag) may be involved in the development of autoimmune thyroid disease. We compared the M-Ag in Graves' thyroid immunologically and biochemically to that in normal thyroid. The concentration of M-Ag, measured with an enzyme-linked immunosorbent assay, was significantly greater in the Graves' microsomes than in normal microsomes. Binding of a patient's microsomal antibody to Graves' microsomes was completely inhibited when the serum was first incubated with normal thyroid microsomes. Sodium dodecylsulfate-polyacrylamide gel electrophoresis and Western blotting were done with a monoclonal antibody to denatured M-Ag. In both Graves' and normal thyroids, M-Ag existed as 107-, 101-, and 95-kDa peptides. After incubation with V8 protease, the residual antigenic peptide had a molecular weight of less than 60,000 and after incubation with trypsin, 95- and 87-kDa peptides and several smaller antigenic peptides were found. There were no significant differences in the pattern of normal and Graves' microsomes after digestion. Two-dimensional gel electrophoresis of Graves' microsomes showed that the isoelectric point for the 107-kDa peptide was at pH 7.2; that for the 101-kDa peptide was at pH 6.2, and that for the 95-kDa peptide was at 6.5. These values were not different from those observed for normal microsomes. These results indicate that M-Ag in Graves' thyroid does not differ from that in normal thyroid, and that microsomal antibodies in autoimmune thyroid disease probably do no arise from differences in the antigen.     

High-throughput marker assays for <Emphasis Type="Italic">FaRPc2</Emphasis>-mediated resistance to Phytophthora crown rot in octoploid strawberry

Phytophthora crown rot (PhCR) caused by Phytophthora cactorum is a destructive disease of the allo-octoploid cultivated strawberry (Fragaria ×ananassa Duch). Many major strawberry cultivars grown worldwide are susceptible to PhCR. Resistance is conferred by the recently-discovered FaRPc2 locus, but high-throughput markers are not yet available for marker-assisted breeding. In the current study, we developed DNA markers for two haplotypes at the FaRPc2 locus associated with resistance, H2 and H3. Marker validation and marker-assisted selection were performed in University of Florida (UF) breeding population. Seven single nucleotide polymorphism-based high resolution melting (HRM) markers linked to H2 and four HRM markers for H3 were developed. One HRM marker, RPCHRM3 linked to H3, was converted to a Kompetitive Allele Specific PCR (KASP) marker. To further examine the utility of the markers, they were screened in University of California Davis cultivars with known phenotypes as well as in 20 diverse accessions with phenotypes that are reported in the literature and that are preserved at the USDA-ARS National Clonal Germplasm Repository, in Corvallis, Oregon. The most informative markers for FaRPc2 resistance are being implemented in the UF strawberry breeding program to improve PhCR resistance.     

Specific autophagy and ESCRT components participate in the unconventional secretion of CFTR

The most common mutation in cystic fibrosis patients is a phenylalanine deletion at position 508 (ΔF508) in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. This mutation impairs cell-surface trafficking of CFTR. During cellular stress, core-glycosylated CFTRΔF508 is transported to the cell surface from the endoplasmic reticulum (ER) via an unconventional route that bypasses the Golgi. However, the mechanisms for this unconventional secretory pathway of CFTR are not well delineated. Here, we report that components of the macroautophagy/autophagy and ESCRT (endosomal sorting complex required for transport) pathways are involved in unconventional secretion of CFTR. In mammalian cells, we found that autophagic pathways were modulated by conditions that also stimulate unconventional secretion, namely ER stress and an ER-to-Golgi transport blockade. Additionally, we found that knockdown of early autophagy components, ATG5 and ATG7, and treatment with pharmacological autophagy inhibitors, wortmannin and 3-methyladenine, abolished the unconventional secretion of CFTR that had been stimulated by ER stress and an ER-to-Golgi blockade. Interestingly, immunoelectron microscopy revealed that GORASP2/GRASP55, which mediates unconventional CFTR trafficking, is present in multivesicular bodies (MVB) and autophagosomal structures under ER stress conditions. A custom small-interfering RNA screen of mammalian ESCRT proteins that mediate MVB biogenesis showed that silencing of some ESCRTs, including MVB12B, inhibited unconventional CFTRΔF508 secretion. Furthermore, MVB12B overexpression partially rescued cell-surface expression and Cl^? channel function of CFTRΔF508. Taken together, these results suggest that components involved in early autophagosome formation and the ESCRT/MVB pathway play a key role in the stress-induced unconventional secretion of CFTR.     

Impact of Hydroxylation and Hydration on the Reactivity of α‐Fe2O3 (0001) and (102) Surfaces under Environmental and Electrochemical Conditions

Hematite (α‐Fe₂O₃) is widely used as a catalytic electrode material in photo‐electrochemical water oxidation, where its surface compositions and stabilities can strongly impact the redox reaction process. Here, its surface configurations in environmental or electrochemical conditions are assessed via density functional theory (DFT) calculations conducted at the Perdew, Burke, and Ernzerhof (PBE)+U level. The most energetically favorable surface domains of α‐Fe₂O₃ (0001) and (102) are predicted by constructing the surface phase diagrams in the framework of first‐principle thermodynamics. The relative surface stabilities are investigated as a function of partial pressures of oxygen and water, temperature, solution pH, and electrode potential not only for perfect bulk terminations but also for defect‐containing surfaces having various degrees of hydroxylation and hydration. In order to assess the impact on the redox reactions of the surface planes as well as of the extent of surface hydration/hydroxylation, the thermodynamics of the four‐step oxygen evolution reaction (OER) mechanism are examined in detail for different models of the α‐Fe₂O₃ (0001) and (102) surfaces. Importantly, the results underline that the nature of the surface termination and the degree of near‐surface hydroxylation give rise to significant variations in the OER overpotentials.     

Seasonal Prevalence of Mosquitoes Collected from Light Traps in Gyeongsangnam Province,Republic of Korea (2013–2014)

Adult mosquito surveillance was conducted from 2013 through 2014 at four cattle sheds, a wild bird refuge, and two residential areas located in Gyeongnam Province in the Republic of Korea. Adult mosquitoes were collected in black light traps from April 1, through November 30. Mosquito surveillance was conducted to figure out population densities of vector mosquitoes, possibly invaded mosquitoes and identify various virus infections at the selected sites. A total of 107,466 females comprising 14 species and 7 genera were collected from 2013 to 2014. The most common species collected were Culex tritaeniorhynchus Giles (63.8%), Anopheles sinensis s.l. (18.9%), Aedes vexans nipponii (Theobald) (7.7%), and Culex pipiens Coquillett (5.1%). Trap indices (TIs) varied widely for species over their range, due to geographical distribution and degree of association with rural and urban communities . The most collected An. sinensis s.l. and Cx. tritaeniorhynchus appeared at a cow shed in Hapcheon (TI 347.5) and a pigsty in Daejeo‐1‐dong, Busan (TI 1,040.8), respectively, due in part to their situation near breeding sites such as rice paddies. The bi‐weekly population densities for mosquito species were variable for each of the years, apparently as a result of variable annual weather conditions. None of the mosquito species collected tested for the flavivirus including Japanese Encephalitis Virus, West Nile Virus, Dengue Virus, and Zika Virus infections by polymerase chain reaction (PCR) assay were positive.