Minimizing higher-order aggregation maximizes iron mobilization by small molecules.

The natural product hinokitiol mobilizes iron across lipid bilayers at low concentrations and restores hemoglobinization in iron transporter protein-deficient systems. But hinokitiol fails to similarly mobilize iron at higher concentrations, limiting its uses in chemical biology and medicine. Here we show that at higher concentrations, hinokitiol3:Fe(III) complexes form large, higher-order aggregates, leading to loss of transmembrane iron mobilization. Guided by this understanding and systematic structure-function studies enabled by modular synthesis, we identified FeM-1269, which minimally aggregates and dose-dependently mobilizes iron across lipid bilayers even at very high concentrations. In contrast to hinokitiol, FeM-1269 is also well-tolerated in animals at high doses for extended periods of time. In a mouse model of anemia of inflammation, FeM-1269 increases serum iron, transferrin saturation, hemoglobin and hematocrit. This rationally developed iron-mobilizing small molecule has enhanced potential as a molecular prosthetic for understanding and potentially treating iron transporter deficiencies.

Mitigation of SARS-CoV-2 transmission at a large public university.

In Fall 2020, universities saw extensive transmission of SARS-CoV-2 among their populations, threatening health of the university and surrounding communities, and viability of in-person instruction. Here we report a case study at the University of Illinois at Urbana-Champaign, where a multimodal "SHIELD: Target, Test, and Tell" program, with other non-pharmaceutical interventions, was employed to keep classrooms and laboratories open. The program included epidemiological modeling and surveillance, fast/frequent testing using a novel low-cost and scalable saliva-based RT-qPCR assay for SARS-CoV-2 that bypasses RNA extraction, called covidSHIELD, and digital tools for communication and compliance. In Fall 2020, we performed >1,000,000 covidSHIELD tests, positivity rates remained low, we had zero COVID-19-related hospitalizations or deaths amongst our university community, and mortality in the surrounding Champaign County was reduced more than 4-fold relative to expected. This case study shows that fast/frequent testing and other interventions mitigated transmission of SARS-CoV-2 at a large public university.

A small molecule redistributes iron in ferroportin-deficient mice and patient-derived primary macrophages.

Deficiencies of the transmembrane iron-transporting protein ferroportin (FPN1) cause the iron misdistribution that underlies ferroportin disease, anemia of inflammation, and several other human diseases and conditions. A small molecule natural product, hinokitiol, was recently shown to serve as a surrogate transmembrane iron transporter that can restore hemoglobinization in zebrafish deficient in other iron transporting proteins and can increase gut iron absorption in FPN1-deficient flatiron mice. However, whether hinokitiol can restore normal iron physiology in FPN1-deficient animals or primary cells from patients and the mechanisms underlying such targeted activities remain unknown. Here, we show that hinokitiol redistributes iron from the liver to red blood cells in flatiron mice, thereby increasing hemoglobin and hematocrit. Mechanistic studies confirm that hinokitiol functions as a surrogate transmembrane iron transporter to release iron trapped within liver macrophages, that hinokitiol-Fe complexes transfer iron to transferrin, and that the resulting transferrin-Fe complexes drive red blood cell maturation in a transferrin-receptor-dependent manner. We also show in FPN1-deficient primary macrophages derived from patients with ferroportin disease that hinokitiol moves labile iron from inside to outside cells and decreases intracellular ferritin levels. The mobilization of nonlabile iron is accompanied by reductions in intracellular ferritin, consistent with the activation of regulated ferritin proteolysis. These findings collectively provide foundational support for the translation of small molecule iron transporters into therapies for human diseases caused by iron misdistribution.

Prevalence of Recombinant Strains of Potato Virus Y in Seed Potato Planted in Idaho and Washington States Between 2011 and 2021.

Potato virus Y (PVY) has emerged as the main reason for potato seed lot rejections, seriously affecting seed potato production in the United States throughout the past 20 years. The dynamics of PVY strain abundance and composition in various potato growing areas of the United States has not been well documented or understood up to now. The objective of this study was to find out the prevalence of PVY strains in potato fields in the Pacific Northwest (PNW), including seed potato production systems in the State of Idaho and commercial potato fields in the Columbia Basin of Washington State between 2011 and 2021. Based on the testing of >10,000 foliar samples during Idaho seed certification winter grow-out evaluations of seed potato lots and seed lot trials in Washington State, a dramatic shift in the PVY strain composition was revealed in the PNW between 2011 and 2016. During this time period, the prevalence of the ordinary, PVYO strain in seed potato dropped 8- to 10-fold, concomitantly with the rise of recombinant strains PVYN-Wi and PVYNTNa, which together accounted for 98% of all PVY positives by 2021. In Idaho seed potato, PVYNTNa strain associated with the potato tuber necrotic ringspot disease (PTNRD) was found to increase threefold between 2011 and 2019, accounting for 24% of all PVY positives in 2019. Mild foliar symptoms induced by recombinant PVY strains may be partially responsible for the proliferation of PVYN-Wi and PVYNTNa in potato crops. A spike of another PTNRD-associated recombinant, PVY-NE11, was recorded in the PNW between 2012 and 2016, but after reaching a 7 to 10% level in 2012 to 2013 this recombinant disappeared from the PNW potato by 2019. Whole genome sequence analysis of the PVY-NE11 suggested this recombinant was introduced in the United States at least three times. The data on PVY strain abundance in the PNW potato crops suggest that virus management strategies must consider the current dominance of the two recombinant PVY strains, PVYN-Wi and PVYNTNa.

Molecular and Biological Characterization of Recombinant Isolates of Potato virus Y Circulating in Potato Fields in Mexico.

Potato virus Y (PVY) is a significant threat to potato (Solanum tuberosum) production in Mexico. The presence of recombinant strains of PVY circulating in potato has been reported in the country, but no systematic study on the genetic diversity of PVY in potato and prevalence of PVY strains has been conducted yet. We report on a series of surveys in seed potato production areas in two states in Mexico, namely, Chihuahua and Jalisco, between 2011 and 2019. PVY was detected through the period of nine years in multiple potato cultivars in both states, often remaining asymptomatic in the most popular cultivars, such as 'Fianna' and 'Agata'. When typed to strain, all PVY samples studied were found to have N-serotype, and were all identified molecularly as isolates of the same recombinant strain, PVYNTN. Five of these PVY isolates were tested on tobacco (Nicotiana tabacum), where they induced vein necrosis supporting the molecular typing. This identification was also confirmed biologically on differential potato cultivars, where one PVYNTN isolate from the 2013 survey triggered the hypersensitive resistance conferred by the Nztbr gene in the cv. Maris Bard. Seven of these Mexican PVYNTN isolates, collected between 2013 and 2019, including two PVY isolates from potato tubers exhibiting potato tuber necrotic ringspot disease, were subjected to whole genome sequencing and found to show a typical PVYNTNa recombinant structure. When subjected to phylogenetic analysis, Mexican PVYNTN sequences clustered in more than three separate clades, suggesting multiple introductions of PVYNTN in the country. The wide circulation of the PVYNTN strain in Mexican potato should be considered by potato producers, to develop mitigation strategies for this PVY strain associated with tuber necrotic symptoms.

Genetic Diversity of Nine Non-Recombinant Potato virus Y Isolates From Three Biological Strain Groups: Historical and Geographical Insights.

Potato virus Y (PVY) isolates from potato currently exist as a complex of six biologically defined strain groups all containing nonrecombinant isolates and at least 14 recombinant minor phylogroups. Recent studies on eight historical UK potato PVY isolates preserved since 1984 found only nonrecombinants. Here, four of five PVY isolates from cultivated potato or wild Solanum spp. collected recently in Australia, Mexico, and the U.S.A. were typed by inoculation to tobacco plants and/or serological testing using monoclonal antibodies. Next, these five modern isolates and four additional historical UK isolates belonging to biological strain groups PVYC, PVYZ, or PVYN obtained from cultivated potato in 1943 to 1984 were sequenced. None of the nine complete PVY genomes obtained were recombinants. Phylogenetic analysis revealed that the four historical UK isolates were in minor phylogroups PVYC1 (YC-R), PVYO-O (YZ-CM1), PVYNA-N (YN-M), or PVYEu-N (YN-RM), Australian isolate YO-BL2 was in minor phylogroup PVYO-O5, and both Mexican isolate YN-Mex43 and U.S.A. isolates YN-MT12_Oth288, YN-MT12_Oth295, and YN-WWAA150131G42 were in minor phylogroup PVYEu-N. When combined, these new findings and those from the eight historical UK isolates sequenced earlier provide important historical insights concerning the diversity of early PVY populations in Europe and the appearance of recombinants in that part of the world. They and four recent Australian isolates sequenced earlier also provide geographical insights about the geographical distribution and diversity of PVY populations in Australia and North America.

Potato Virus Y (PVY) Isolates from Solanum betaceum Represent Three Novel Recombinants Within the PVYN Strain Group and Are Unable to Systemically Spread in Potato.

Tamarillo, or tree tomato (Solanum betaceum), is a perennial small tree or shrub species cultivated in subtropical areas for fresh fruit and juice production. In Ecuador, tamarillo orchards are affected by several viruses, with one previously identified as potato virus Y (PVY); however, the specific strain composition of PVY in tamarillo was not determined. In 2015 and 2016, eight tamarillo plants exhibiting symptoms of leaf drop, mosaic, and mottled fruit were sampled near Tumbaco and Quito, Ecuador. These tamarillo PVY isolates were able to systemically infect tobacco, Nicotiana benthamiana, naranjilla, and tamarillo. Seven of the eight PVY isolates from tamarillo exhibited N-serotype, while one of the PVY isolates studied, Tam15, had no identifiable serotype. One isolate, Tam17, had N-serotype but produced asymptomatic systemic infection in tobacco. In tamarillo, four tamarillo isolates induced mosaic and slight growth retardation and were unable to systemically infect pepper or potato. Tamarillo, on the other hand, was unable to support systemic infection of PVY isolates belonging to the PVYO and PVYEu-N strains. The whole genomes of eight PVY isolates were sequenced from a series of overlapping RT-PCR fragments. Phylogenetically, tamarillo PVY isolates were found to belong to the large PVYN lineage, in a new tamarillo clade. Recombination analysis revealed that these tamarillo PVY isolates represent at least three novel recombinant types not reported before. The combination of the biological and molecular properties found in these eight PVY isolates suggested the existence of a new tamarillo strain of PVY that may have coevolved with S. betaceum.

MORC3 Is a Target of the Influenza A Viral Protein NS1.

Microrchidia 3 (MORC3), a human ATPase linked to several autoimmune disorders, has been characterized both as a negative and positive regulator of influenza A virus. Here, we report that the CW domain of MORC3 (MORC3-CW) is targeted by the C-terminal tail of the influenza H3N2 protein NS1. The crystal structure of the MORC3-CW:NS1 complex shows that NS1 occupies the same binding site in CW that is normally occupied by histone H3, a physiological ligand of MORC3-CW. Comparable binding affinities of MORC3-CW to H3 and NS1 peptides and to the adjacent catalytic ATPase domain suggest that the viral protein can compete with the host histone for the association with CW, releasing MORC3 autoinhibition and activating the catalytic function of MORC3. Our structural, biochemical, and cellular analyses suggest that MORC3 might affect the infectivity of influenza virus and therefore has a role in cell immune response.

Identification and Molecular Characterization of Recombinant Potato Virus Y (PVY) in Potato from South Korea, PVYNTN Strain.

Potato is an important source of food in South Korea, and viruses represent a significant threat to sustainable and profitable potato production. However, information about viruses affecting the potato crop in South Korea is limited. In 2017, potato plants of five cultivars exhibiting foliar mosaic, crinkling, and mottle were collected in two seed potato production areas, in Gangwon-do and Jeollabuk-do Provinces, and subjected to virus testing and characterization. Potato virus Y (PVY) was found associated with mosaic symptoms, and samples were characterized using reverse transcription polymerase chain reaction (RT-PCR) and whole genome sequencing. All analyzed PVY-positive samples were found to represent the same recombinant PVY strain: PVYNTN. Three PVY isolates were subjected to whole genome sequencing using overlapping RT-PCR fragments and Sanger methodology, and all three were confirmed to represent strain PVYNTNa after a recombination analysis of the complete genomes. In phylogenetic analysis, the three South Korean isolates were placed most closely to several PVYNTNa isolates reported from Japan and Vietnam, suggesting a common source of infection. This is the first report and complete molecular characterization of a PVYNTN strain present in the country, and because this strain induces tuber necrotic ringspot disease in susceptible cultivars of potato, appropriate management tools need to be implemented to mitigate potential tuber quality losses.

Genetic diversity of potato virus Y (PVY): sequence analyses reveal ten novel PVY recombinant structures.

The potato virus Y (PVY) complex includes five non-recombinant strains and a growing number of recombinants. Up to now, the bulk of these PVY recombinants were found to be composed of genome segments coming from only two "parental" genomes, PVYO and PVYEu-N, with a small minority including segments from other parents, e.g. PVYC, PVYNA-N, and a segment of the recombinant strain PVY-NE11. Here, comprehensive analyses of 396 whole genomes of PVY isolates from 34 countries and a variety of hosts revealed 28 isolates to be rare or novel recombinants. When subjected to a thorough recombination analysis, these 28 PVY isolates were found to represent 25 poorly sampled PVY recombinant structures, ten of which had not been recognized previously. Nine of the ten novel structures carried parental sequences from PVYNA-N or PVY-NE11 strains recombined with PVYO and PVYEu-N sequences, while seven of the new structures contained sequences from three different parents. The number of known PVY recombinant patterns now stands at thirty six. These recombinant structures present a challenge for PVY strain typing, but may shed light on interactions between PVY and host resistance genes.

Characterization of a New Tymovirus Causing Stunting and Chlorotic Mosaic in Naranjilla (Solanum quitoense).

Naranjilla ("little orange"), also known as lulo (Solanum quitoense Lam.), is a perennial shrub species cultivated in the Andes for fresh fruit and juice production. In 2015, a naranjilla plant exhibiting stunting, mosaic, and chlorotic spots was sampled in the Pastaza province of Ecuador and maintained under greenhouse conditions. An infectious agent was mechanically transmitted to indicator plants and was subjected to biological and molecular characterization. Spherical particles approximately 30 nm in diameter, composed of a single 20-kDa capsid protein, were observed under an electron microscope in infected naranjilla plants. High-throughput sequencing conducted on inoculated Nicotiana benthamiana plants produced a single sequence contig sharing the closest relationship with several tymoviruses. The entire 6,245-nucleotide genome of a new tymovirus was amplified using reverse-transcription polymerase chain reaction and resequenced with the Sanger methodology. The genome had three open reading frames typical of tymoviruses, and displayed a whole-genome nucleotide identity level with the closest tymovirus, Eggplant mosaic virus, at 71% (90% coverage). This tymovirus from naranjilla was able to systemically infect eggplant, tamarillo, N. benthamiana, and naranjilla. In naranjilla, it produced mosaic, chlorotic spots, and stunting, similar to the symptoms observed in the original plant. The virus was unable to infect potato and tobacco and unable to systemically infect pepper plants, replicating only in inoculated leaves. We concluded that this virus represented a new tymovirus infecting naranjilla, and proposed the tentative name Naranjilla chlorotic mosaic virus (NarCMV).

Potato virus Y (PVY) Isolates from Physalis peruviana are Unable to Systemically Infect Potato or Pepper and Form a Distinct New Lineage Within the PVYC Strain Group.

Poha, or cape gooseberry (Physalis peruviana L.), is a plant species cultivated in Hawaii for fresh fruit production. In 2015, an outbreak of virus symptoms occurred on poha farms in the South Kohala District of the island of Hawaii. The plants displayed mosaic, stunting, and leaf deformation, and produced poor fruit. Initial testing found the problem associated with Potato virus Y (PVY) infection. Six individual PVY isolates, named Poha1 to Poha6, were collected from field-grown poha plants and subjected to biological and molecular characterization. All six isolates induced mosaic and vein clearing in tobacco, and three of them exhibited O-serotype while the other three reacted only with polyclonal antibodies and had no identifiable serotype. Until now, PVY isolates have been broadly divided into pepper or potato adapted; however, these six PVY isolates from poha were unable to establish systemic infection in pepper and in four tested potato cultivars. Whole-genome sequences for the six isolates were determined, and no evidence of recombination was found in any of them. Phylogenetic analysis placed poha PVY isolates in a distinct, monophyletic "Poha" clade within the PVYC lineage, suggesting that they represented a novel, biologically and evolutionarily unique group. The genetic diversity within this poha PVYC clade was unusually high, suggesting a long association of PVYC with this solanaceous host or a prolonged geographical separation of PVYC in poha in Hawaii.

Phylogenetic study of recombinant strains of Potato virus Y.

Potato virus Y (PVY) exists as a complex of strains, including a growing number of recombinants. Evolution of PVY proceeds through accumulation of mutations and more rapidly through recombination. Here, the role of recombination in PVY evolution and the origin of common PVY recombinants were studied through whole genome analysis of 119 newly sequenced PVY isolates largely from U.S. potato, and subsequent combined phylogenetic and recombination analyses with an additional 166 whole PVY genomes from the GenBank database. Two novel PVYC recombinants were sequenced and identified, along with one novel PVYN:O recombinant. Sequence diversity in the parental sequences made it possible to trace the origins of all recombinant types of PVY, which also showed remarkable sequence diversity in most cases. The results suggested that the common recombinant PVY strains originated more than once, from different parental sequences.

Occurrence of Diverse Recombinant Strains of Potato virus Y Circulating in Potato Fields in Egypt.

Potato is one of the staple crops in Egypt, grown under irrigation almost continuously year-round. Potato virus Y (PVY) has been reported as one of the main viruses affecting potatoes in Egypt, but limited information is available on PVY strains circulating in potato fields in the country. From 2014 to 2016, virus surveys were conducted in several potato-growing governorates of Egypt, and PVY-positive samples were found to represent at least five distinct recombinant PVY strains, including PVYNTN and PVYN-Wi. Whole genome sequences were determined for four isolates representing strains PVY-SYR-III (Egypt7), PVY-261-4 (Egypt11), PVYNTNa (Egypt35), and a novel recombinant named Egypt24 that combined molecular properties of strains PVY-261-4 and PVY-Wilga156var. At least three recombinants found in Egypt in potato were previously found associated with potato tuber necrotic ringspot disease (PTNRD). The identification of multiple recombinant types of PVY in potato in Egypt, including the novel recombinant Egypt24, suggests a wide presence of PTNRD-inducing virus strains in the country.

Strain-Specific Resistance to Potato virus Y (PVY) in Potato and Its Effect on the Relative Abundance of PVY Strains in Commercial Potato Fields.

Potato virus Y (PVY) is a serious threat to potato production due to effects on tuber yield and quality, in particular, due to induction of potato tuber necrotic ringspot disease (PTNRD), typically associated with recombinant strains of PVY. These recombinant strains have been spreading in the United States for the past several years, although the reasons for this continuing spread remained unclear. To document and assess this spread between 2011 and 2015, strain composition of PVY isolates circulating in the Columbia Basin potato production area was determined from hundreds of seed lots of various cultivars. The proportion of nonrecombinant PVYO isolates circulating in Columbia Basin potato dropped ninefold during this period, from 63% of all PVY-positive plants in 2011 to less than 7% in 2015. This drop in PVYO was concomitant with the rise of the recombinant PVYN-Wi strain incidence, from less than 27% of all PVY-positive plants in 2011 to 53% in 2015. The proportion of the PVYNTN recombinant strain, associated with PTNRD symptoms in susceptible cultivars, increased from 7% in 2011 to approximately 24% in 2015. To further address the shift in strain abundance, screenhouse experiments were conducted and revealed that three of the four most popular potato cultivars grown in the Columbia Basin exhibited strain-specific resistance against PVYO. Reduced levels of systemic movement of PVYO in such cultivars would favor spread of recombinant strains in the field. The negative selection against the nonrecombinant PVYO strain is likely caused by the presence of the Nytbr gene identified in potato cultivars in laboratory experiments. Presence of strain-specific resistance genes in potato cultivars may represent the driving force changing PVY strain composition to predominantly recombinant strains in potato production areas.

Characterization of Beet curly top virus Strains Circulating in Beet Leafhoppers (Hemiptera: Cicadellidae) in Northeastern Oregon.

The beet leafhopper, Circulifer tenellus, is an agriculturally important pest, particularly in the western United States. This insect transmits the Beet curly top virus (BCTV) to multiple crops, including bean, tomato, and pepper. In this study, we investigated the incidence of BCTV in individual leafhoppers collected at several sites in northeastern Oregon during the growing season in 2007, 2008, and 2009. Of the 800 insects tested, 151 (18.9%) were found positive for the virus. Percentage of virus incidence varied from 0% at one location in 2009 to a high of 55.6% for a location sampled in 2008. The complete virus genomes from one virus-positive insect collected in each of the 3 years were determined. BLAST analysis of the BCTV whole-genome sequences from 2007, 2008, and 2009 insects showed 98, 94, and 96% identities with the BCTV-Worland sequence (AY134867), respectively. The BCTV_2008 sequence showed the greatest identity (96%) with another BCTV genomic sequence (JN817383), and was found to be a recombinant between the BCTV-Worland type, representing the majority of the genome (approximately 2.2 kb), and the BCTV-CFH type that provided an approximately 0.8-kb fragment spanning replication-related genes C1 and C2. This area of the BCTV genome, between the C1 and C2 genes, was previously found to carry symptom determinants of the virus, and the data may suggest more severe effects of BCTV during the 2008 season. Results indicate that BCTV is common and widespread in C. tenellus in eastern Oregon and that there is substantial genetic diversity among the virus strains present in this important field and vegetable crop-growing region.