scholarly journals Southern corn rust caused by Puccinia polysora Underw: a review

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Qiuyu Sun ◽  
Leifu Li ◽  
Fangfang Guo ◽  
Keyu Zhang ◽  
Jiayu Dong ◽  
...  
Keyword(s):  
Considerable Increase ◽  
Current Knowledge ◽  
Wide Distribution ◽  
Long Distance ◽  
Physiological Races ◽  
Southern Corn Rust ◽  
Maize Varieties ◽  
Puccinia Polysora ◽  
China Life ◽  
Fast Evolution

AbstractSouthern corn rust (SCR) caused by Puccinia polysora Underw is one of the most devastating maize diseases, resulting in substantial yield losses worldwide. The pathogen is an obligate biotrophic parasite that is difficult to culture on artificial media. In recent years, the disease has become prevalent—both globally and in China—and increasing difficult to control because of its wide distribution, long-distance migration, multiple physiological races and fast evolution, all of which have contributed to a considerable increase in the risks of associated epidemics. In this review, we summarize the current knowledge of P. polysora, with emphasis on its global distribution (particularly in China), life and disease cycle, population genetics, migration, physiological races, resistance genes in maize and management. Understanding the underlying factors and processes in SCR epidemics should facilitate management of the disease and breeding for resistant maize varieties.

scholarly journals Assessment of the American Flamingo distribution, trends, and important breeding areas

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244117
Author(s):  
Leopoldo Torres-Cristiani ◽  
Salima Machkour-M’Rabet ◽  
Sophie Calmé ◽  
Holger Weissenberger ◽  
Griselda Escalona-Segura
Keyword(s):  
The United States ◽  
Wide Distribution ◽  
Global Perspective ◽  
Range Extension ◽  
Technological Advancement ◽  
Science Data ◽  
Long Distance ◽  
The 1960S ◽  
American Flamingo ◽  
Phoenicopterus Ruber

The American Flamingo, Phoenicopterus ruber, is a charismatic bird distributed throughout the Caribbean, North and South America. Its wide distribution, the complexity of international monitoring due to its capacity for long-distance flying, and a focus mostly on local populations, make it difficult to understand the dynamics between sites. Here, we took advantage of the citizen eBird science project to present a global perspective on the distribution of the American Flamingo, and identify the potentially most important countries for breeding. We obtained 16,930 records for the Americas from the 1960s until October 2018, of which 9,283 could be used for our objectives. The eBird database indicated a considerable increase in the total number of records over the last decade (2010s), probably reflecting an increase in tourism facilities, research investment, technological advancement, interest in conservation, and the worldwide availability of eBird. We also observed a range extension in the Gulf of Mexico in the United States and a significant recolonization in the Florida Peninsula. The apparent range extension to the South is more likely to be linked to biases in the data; for example, in any given country the number of records might reflect either reporting efforts or actual numbers. eBird data confirmed that six countries host the main breeding colonies (Bahamas, Bonaire, Cuba, Ecuador, Mexico, and Venezuela). We suggest three additional countries as potential breeding areas for the species (Colombia, Curaçao, Turks and Caicos Islands) for which more field observations are necessary to support this possibility. This global appraisal of the distribution of the American Flamingo using citizen science data provides valuable information for national and international management and conservation programs such as the need to verify the species breeding status in areas where it appears to be expanding its distribution.

scholarly journals Extracellular Vesicles and MicroRNA: Putative Role in Diagnosis and Treatment of Diabetic Retinopathy

Antioxidants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 705 ◽  
Author(s):  
Beatriz Martins ◽  
Madania Amorim ◽  
Flávio Reis ◽  
António Francisco Ambrósio ◽  
Rosa Fernandes
Keyword(s):  
Diabetic Retinopathy ◽  
Extracellular Vesicles ◽  
Vision Loss ◽  
Current Knowledge ◽  
Critical Role ◽  
Cell Communication ◽  
Cell Junctions ◽  
Low Grade ◽  
Long Distance ◽  
Advanced Stages

Diabetic retinopathy (DR) is a complex, progressive, and heterogenous retinal degenerative disease associated with diabetes duration. It is characterized by glial, neural, and microvascular dysfunction, being the blood-retinal barrier (BRB) breakdown a hallmark of the early stages. In advanced stages, there is formation of new blood vessels, which are fragile and prone to leaking. This disease, if left untreated, may result in severe vision loss and eventually legal blindness. Although there are some available treatment options for DR, most of them are targeted to the advanced stages of the disease, have some adverse effects, and many patients do not adequately respond to the treatment, which demands further research. Oxidative stress and low-grade inflammation are closely associated processes that play a critical role in the development of DR. Retinal cells communicate with each other or with another one, using cell junctions, adhesion contacts, and secreted soluble factors that can act in neighboring or long-distance cells. Another mechanism of cell communication is via secreted extracellular vesicles (EVs), through exchange of material. Here, we review the current knowledge on deregulation of cell-to-cell communication through EVs, discussing the changes in miRNA expression profiling in body fluids and their role in the development of DR. Thereafter, current and promising therapeutic agents for preventing the progression of DR will be discussed.

Modeling ships' ballast water as invasion threats to the Great Lakes

2002 ◽  
Vol 59 (7) ◽  
pp. 1245-1256 ◽  
Author(s):  
Hugh J MacIsaac ◽  
Thomas C Robbins ◽  
Mark A Lewis
Keyword(s):  
Great Lakes ◽  
Ballast Water ◽  
Aquatic Ecosystems ◽  
Propagule Pressure ◽  
Current Knowledge ◽  
Invasion Process ◽  
Long Distance ◽  
Invasion Models ◽  
Terrestrial Habitats ◽  
Shipping Traffic

The spread of nonindigenous species (NIS) in aquatic ecosystems provides an opportunity to develop new perspectives on the invasion process. In this paper we review existing invasion models, most of which were developed to describe invasions of terrestrial habitats, and propose an alternative that explores long-distance invasions mediated by discharge of contaminated ballast water by ships inbound to the Great Lakes. Based on current knowledge of shipping traffic to the Great Lakes, our model predicts that mid-ocean exchange of ballast water lowers propagule delivery by approximately three to four orders of magnitude relative to unexchanged ballast water. Propagule pressure of individual ships that enter the Great Lakes loaded with cargo and that declare "no ballast on board" (NOBOB) is typically one to two orders of magnitude higher than that of vessels that exchange ballast. Because NOBOB vessels dominate (~90%) inbound traffic into the Great Lakes, these vessels collectively appear to pose the greatest risk of new introductions, even though their individual risks are low.

Phylogeographic structuring of the amphidromous shrimp Atya scabra (Crustacea, Decapoda, Atyidae) unveiled by range-wide mitochondrial DNA sampling

2019 ◽  
Vol 70 (8) ◽  
pp. 1078 ◽  
Author(s):  
Caio M. C. A. Oliveira ◽  
Mariana Terossi ◽  
Fernando L. Mantelatto
Keyword(s):  
Wide Distribution ◽  
Genetic Connectivity ◽  
Biological Traits ◽  
Long Distance ◽  
Western Atlantic ◽  
Lineage Differentiation ◽  
Genetic Groups ◽  
16S Gene ◽  
Haplotype Networks ◽  
Dna Sampling

Species with biological traits favourable to long-distance marine larval dispersal might show a phylogeographic structuring over broad regions, even when they are genetically connected within smaller scales. Here, we evaluated this hypothesis by using the widespread amphidromous shrimp Atya scabra, predicting a genetic discontinuity across biogeographical barriers throughout the Western Gulf of Mexico (WGM), Caribbean Sea (CS), south-western Atlantic (SWA) and eastern Atlantic (EA). Using cytochrome oxidase subunit 1 (COI) and 16S ribosomal unit (16S) gene fragments, we did a phylogeographic assessment and genetic characterisation with Bayesian clustering, AMOVA, haplotype networks and demographic analyses. As predicted, three discrete genetic groups, corresponding to the regions WGM, CS and EA, were uncovered by COI, as well an unpredicted SWA+CS group. The 16S fragment detected a low genetic variation, probably owing to a recent lineage differentiation, which was estimated by the COI molecular clock. We evaluated the role of the biological traits of A. scabra, as well as the consequences of Panama Isthmus closure and Pleistocene glaciation cycles in the lineage isolation of WGM and EA, as well as the genetic connectivity shown within regions and between CS and SWA. Our results highlighted that amphidromous species genetically connected over large scales should be genetically characterised in their wide distribution to provide more comprehensive systematics and to assist decision-making in biological conservation.

Major stopover regions and migratory bottlenecks for Nearctic-Neotropical landbirds within the Neotropics: a review

2017 ◽  
Vol 28 (1) ◽  
pp. 1-26 ◽  
Author(s):  
NICHOLAS J. BAYLY ◽  
KENNETH V. ROSENBERG ◽  
WENDY E. EASTON ◽  
CAMILA GÓMEZ ◽  
JAY CARLISLE ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Migratory Birds ◽  
Current Knowledge ◽  
Boreal Winter ◽  
Long Distance ◽  
Important Distinction ◽  
Conservation Actions ◽  
Neotropical Migratory Birds ◽  
And Migration ◽  
Multiple Species

SummaryNearly 300 species of landbirds, whose populations total billions, migrate between the Neotropics and North America. Many migratory populations are in steep decline, and migration is often identified as the greatest source of annual mortality. Identifying birds’ needs on migration is therefore central to designing conservation actions for Nearctic-Neotropical migratory birds; yet migration through the Neotropics is a significant knowledge gap in our understanding of the full annual cycle. Here, we synthesise current knowledge of Neotropical stopover regions and migratory bottlenecks, focusing on long-distance, migratory landbirds that spend the boreal winter in South America. We make the important distinction between “true” stopover—involving multi-day refuelling stops—and rest-roost stops lasting < 24 hours, citing a growing number of studies that show individual landbirds making long stopovers in just a few strategic areas, to accumulate large energy reserves for long-distance flights. Based on an exhaustive literature search, we found few published stopover studies from the Neotropics, but combined with recent tracking studies, they describe prolonged stopovers for multiple species in the Orinoco grasslands (Llanos), the Sierra Nevada de Santa Marta (Colombia), and the Yucatan Peninsula. Bottlenecks for diurnal migrants are well described, with the narrowing Central American geography concentrating millions of migrating raptors at several points in SE Mexico, Costa Rica, Panama and the Darién. However, diurnally migrating aerial insectivores remain understudied, and determining stopover/roost sites for this steeply declining group is a priority. Despite advances in our knowledge of migration in the Neotropics, we conclude that major knowledge gaps persist. To identify stopover sites and habitats and the threats they face, we propose a targeted and collaborative research agenda at an expanded network of Neotropical sites, within the context of regional conservation planning strategies.

scholarly journals Causes and Consequences of Spatial Within-Host Viral Spread

Viruses ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 627 ◽  
Author(s):  
Molly Gallagher ◽  
Christopher Brooke ◽  
Ruian Ke ◽  
Katia Koelle
Keyword(s):  
Influenza A ◽  
Current Knowledge ◽  
Control Strategies ◽  
Experimental Studies ◽  
Spatial Dynamics ◽  
Spatial Process ◽  
Influenza A Viruses ◽  
Long Distance ◽  
Viral Spread ◽  
Shed Light

The spread of viral pathogens both between and within hosts is inherently a spatial process. While the spatial aspects of viral spread at the epidemiological level have been increasingly well characterized, the spatial aspects of viral spread within infected hosts are still understudied. Here, with a focus on influenza A viruses (IAVs), we first review experimental studies that have shed light on the mechanisms and spatial dynamics of viral spread within hosts. These studies provide strong empirical evidence for highly localized IAV spread within hosts. Since mathematical and computational within-host models have been increasingly used to gain a quantitative understanding of observed viral dynamic patterns, we then review the (relatively few) computational modeling studies that have shed light on possible factors that structure the dynamics of spatial within-host IAV spread. These factors include the dispersal distance of virions, the localization of the immune response, and heterogeneity in host cell phenotypes across the respiratory tract. While informative, we find in these studies a striking absence of theoretical expectations of how spatial dynamics may impact the dynamics of viral populations. To mitigate this, we turn to the extensive ecological and evolutionary literature on range expansions to provide informed theoretical expectations. We find that factors such as the type of density dependence, the frequency of long-distance dispersal, specific life history characteristics, and the extent of spatial heterogeneity are critical factors affecting the speed of population spread and the genetic composition of spatially expanding populations. For each factor that we identified in the theoretical literature, we draw parallels to its analog in viral populations. We end by discussing current knowledge gaps related to the spatial component of within-host IAV spread and the potential for within-host spatial considerations to inform the development of disease control strategies.

scholarly journals Similar yet critically different: the distribution, dynamics and function of histone variants

2020 ◽  
Vol 71 (17) ◽  
pp. 5191-5204 ◽  
Author(s):  
Aline V Probst ◽  
Bénédicte Desvoyes ◽  
Crisanto Gutierrez
Keyword(s):  
Current Knowledge ◽  
Specific Binding ◽  
Expression Patterns ◽  
Histone Variants ◽  
Wide Distribution ◽  
Core Histones ◽  
Dynamics And Function ◽  
And Function ◽  
Histone Deposition ◽  
Dna Template

Abstract Organization of the genetic information into chromatin plays an important role in the regulation of all DNA template-based reactions. The incorporation of different variant versions of the core histones H3, H2A, and H2B, or the linker histone H1 results in nucleosomes with unique properties. Histone variants can differ by only a few amino acids or larger protein domains and their incorporation may directly affect nucleosome stability and higher order chromatin organization or indirectly influence chromatin function through histone variant-specific binding partners. Histone variants employ dedicated histone deposition machinery for their timely and locus-specific incorporation into chromatin. Plants have evolved specific histone variants with unique expression patterns and features. In this review, we discuss our current knowledge on histone variants in Arabidopsis, their mode of deposition, variant-specific post-translational modifications, and genome-wide distribution, as well as their role in defining different chromatin states.

scholarly journals Root Involvement in Plant Responses to Adverse Environmental Conditions

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 942 ◽  
Author(s):  
Vicente Vives-Peris ◽  
María F. López-Climent ◽  
Rosa M. Pérez-Clemente ◽  
Aurelio Gómez-Cadenas
Keyword(s):  
Abiotic Stress ◽  
Current Knowledge ◽  
Physiological Responses ◽  
Root Exudation ◽  
Stress Conditions ◽  
Global Changes ◽  
Plant Responses ◽  
Long Distance ◽  
Regulatory Pathways ◽  
Adverse Environmental Conditions

Climate change is altering the environment in which plants grow and survive. An increase in worldwide Earth surface temperatures has been already observed, together with an increase in the intensity of other abiotic stress conditions such as water deficit, high salinity, heavy metal intoxication, etc., generating harmful conditions that destabilize agricultural systems. Stress conditions deeply affect physiological, metabolic and morphological traits of plant roots, essential organs for plant survival as they provide physical anchorage to the soil, water and nutrient uptake, mechanisms for stress avoidance, specific signals to the aerial part and to the biome in the soil, etc. However, most of the work performed until now has been mainly focused on aerial organs and tissues. In this review, we summarize the current knowledge about the effects of different abiotic stress conditions on root molecular and physiological responses. First, we revise the methods used to study these responses (omics and phenotyping techniques). Then, we will outline how environmental stress conditions trigger various signals in roots for allowing plant cells to sense and activate the adaptative responses. Later, we discuss on some of the main regulatory mechanisms controlling root adaptation to stress conditions, the interplay between hormonal regulatory pathways and the global changes on gene expression and protein homeostasis. We will present recent advances on how the root system integrates all these signals to generate different physiological responses, including changes in morphology, long distance signaling and root exudation. Finally, we will discuss the new prospects and challenges in this field.

RNA:DNA triple helices: from peculiar structures to pervasive chromatin regulators

2021 ◽  
Author(s):  
Andreas Adam Greifenstein ◽  
SoYoung Jo ◽  
Holger Bierhoff
Keyword(s):  
Protein Interactions ◽  
Current Knowledge ◽  
Double Helix ◽  
Wide Distribution ◽  
Detection Methods ◽  
Protein Coding ◽  
Functional Characterisation ◽  
Triple Helices ◽  
Dna Strand ◽  
Dna Double Helix

Abstract The genomes of complex eukaryotes largely contain non-protein-coding DNA, which is pervasively transcribed into a plethora of non-coding RNAs (ncRNAs). The functional importance of many of these ncRNAs has been investigated in the last two decades, revealing their crucial and multifaceted roles in chromatin regulation. A common mode of action of ncRNAs is the recruitment of chromatin modifiers to specific regions in the genome. Whereas many ncRNA–protein interactions have been characterised in detail, binding of ncRNAs to their DNA target sites is much less understood. Recently developed RNA-centric methods have mapped the genome-wide distribution of ncRNAs, however, how ncRNAs achieve locus-specificity remains mainly unresolved. In terms of direct RNA–DNA interactions, two kinds of triple-stranded structures can be formed: R-loops consisting of an RNA:DNA hybrid and a looped out DNA strand, and RNA:DNA triple helices (triplexes), in which the RNA binds to the major groove of the DNA double helix by sequence-specific Hoogsteen base pairing. In this essay, we will review the current knowledge about RNA:DNA triplexes, summarising triplex formation rules, detection methods, and ncRNAs reported to engage in triplexes. While the functional characterisation of RNA:DNA triplexes is still anecdotal, recent advances in high-throughput and computational analyses indicate their widespread distribution in the genome. Thus, we are witnessing a paradigm shift in the appreciation of RNA:DNA triplexes, away from exotic structures towards a prominent mode of ncRNA–chromatin interactions.

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