scholarly journals Puccinia jaceae var. solstitialis Teliospore Priming on Yellow Starthistle

2009 ◽  
Vol 99 (1) ◽  
pp. 67-72 ◽  
Author(s):  
A. J. Fisher ◽  
B. J. Aegerter ◽  
T. R. Gordon ◽  
L. Smith ◽  
D. M. Woods

Following the introduction of Puccinia jaceae var. solstitialis to California for biological control of yellow starthistle (Centaurea solstitialis, Asteraceae), teliospores, pycnia, and multiple urediniospore generations have been observed in the field. Because urediniospores have a relatively short life span in the field, functioning teliospores are expected to be necessary for the permanent establishment of P. jaceae var. solstitialis in California. To determine if conditions in California were conducive to this, teliospore emergence and priming were evaluated in the field. A factorial experiment in the laboratory with five incubation times and three incubation temperatures was used to determine teliospore priming requirements. Teliospore production coincided with plant senescence in August and September at two sites in 2 years; fewer teliospores were produced in 2006, suggesting inconsistent teliospore production may limit population growth and contribute to local extinctions in some areas. When teliospores were primed in the field, germination was low through the fall and abruptly peaked in January during both years. In the laboratory, teliospore germination increased as incubation time increased from 2 to 6 weeks and temperatures decreased from 12 to 4°C. A degree-hour model derived from laboratory data accurately predicts when teliospores are primed for germination in the field. Based on the results obtained in this study, it is apparent that teliospore germination can occur over a range of priming conditions. However, lower temperatures and longer incubation periods are superior in breaking teliospore dormancy.

Plant Disease ◽  
2006 ◽  
Vol 90 (4) ◽  
pp. 425-428 ◽  
Author(s):  
T. L. Widmer ◽  
F. Guermache

Yellow starthistle (Centaurea solstitialis) is an annual invasive weed in the United States with Mediterranean origins. The expense of chemical control and the vast area of invasion make this weed an appropriate target for classical biological control. Observations of a field site in southern France revealed small orange galls on the leaves of yellow starthistle seedlings caused by the fungus Synchytrium solstitiale. Inoculation of yellow starthistle seedlings with a suspension of zoospores released from infected tissue resulted in infection. Ten days after inoculation, typical orange galls appeared on the exposed tissue. Preliminary host range testing showed up to 100% infection of C. solstitialis seedlings from both France and the United States and infection of Carthamus tinctorius, Centaurea americana, C. diffusa, C. rothrockii, C. squarrosa, and Helianthus annuus seedlings. No symptoms were observed on seedlings of Centaurea calcitrapa, C. maculosa, C. sulfurea, Cirsium californica, C. occidentale, Cynera cardunculus, and Taraxacum officinale. Zoospores were released in a pH range between 4.45 and 8.25 and optimally at temperatures between 5 and 15°C. Infection of yellow starthistle seedlings occurred after a minimum 1-h exposure to a zoospore suspension at 20°C.


2018 ◽  
Vol 40 (8) ◽  
pp. 1270-1280
Author(s):  
Tokunbo Ojo

With the mixture of government-owned media outlets and private media establishments, Nigerian news media industry is deemed as one of the leading media industries in Africa. But, in spite of its leading status on the continent, the industry is plagued with a series of multi-faceted challenges of sustainability that is rooted in the socio-economic and political contexts. Consequently, privately owned media outlets have short-life span in Nigeria. This article assesses the challenges of news media sustainability in Nigeria. The article underscores the adverse effects of structural deficit in the democratic norms and institutional capabilities on the news media sustainability in Nigeria.


Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2878
Author(s):  
Ehsan Bari ◽  
Asghar Sistani ◽  
Jeffrey J. Morrell ◽  
Antonio Pizzi ◽  
Mohammad Reza Akbari ◽  
...  

Rapid global population growth has led to an exponential increase in the use of disposable materials with a short life span that accumulate in landfills. The use of non-biodegradable materials causes severe damage to the environment worldwide. Polymers derived from agricultural residues, wood, or other fiber crops are fully biodegradable, creating the potential to be part of a sustainable circular economy. Ideally, natural fibers, such as the extremely strong fibers from hemp, can be combined with matrix materials such as the core or hurd from hemp or kenaf to produce a completely renewable biomaterial. However, these materials cannot always meet all of the performance attributes required, necessitating the creation of blends of petroleum-based and renewable material-based composites. This article reviews composites made from natural and biodegradable polymers, as well as the challenges encountered in their production and use.


Author(s):  
Liesbeth Plateau

This contribution presents an introductory analysis of one of the key players of the socalled“stenciled revolution” in Flanders in the nineteen sixties. Before concepts likeprovo distressed the entire societal and cultural life in the Netherlands, certain phenomenain Flanders anticipated to this. From 1963, small stenciled magazines shot up likemushrooms in the Flemish literary field. Due to their aggressive stand against the literaryestablishment, the critics quickly caught sight of them and engaged in an energeticpolemic. Because of their involvement in the literary polemics, the stenciled magazinesshortly determined the literary life to a high degree. However, partly due to their complexhistory and short life span, a systematic investigation of this phenomenon has not yet beenconducted. Nevertheless, the underground- magazines of the “stenciled revolution” are invarious ways relevant to a renewed literary history, as they explore both the literary-criticaland the creative-literary boundaries of the traditional contrast between literature andnon-literature. In this article, I focus on one of the most creative-literary oriented of theseFlemish stenciled magazines, namely daele (1966-1968), to gain an insight into the identityof the “stenciled revolution”.


2020 ◽  
pp. 551-562
Author(s):  
Alberto Mora

The U.S. policy to adopt torture1 as an interrogation technique after the 9/11 attacks had a relatively short life span, yet it was deeply corrosive to the national interest and continues to be.2 First adopted by the administration of President George W. Bush in the summer of 2002, it was formally terminated by an executive order signed by President Barrack Obama on January 22, 2009, his second day in office. The actual official ...


Author(s):  
Jinju Kim ◽  
Harrison Kim

AbstractShort-life cycle products are frequently replaced and discarded despite being resource-intensive. The short life span and the low utilization rate of the end-of-life products cause severe environmental problems and waste of resources. In the case of short-life cycle products, a new generation of products is released sooner than other products, therefore there are the opportunities to have various generations of products during the remanufacturing process. The commonality between generations increases the intergenerational component compatibility, which increases the efficiency of the manufacturing and remanufacturing processes, while at the same time weakening the performance difference between generations. This paper proposes a mathematical model to investigate the effect of commonality among generations on the overall production process. Based on various given new generation product designs with different commonality, we aim to propose optimal production planning and pricing strategies to maximize the total profitability and investigate how the results vary according to the commonality strategies between product generations.


mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Celina M. Abreu ◽  
Rebecca T. Veenhuis ◽  
Claudia R. Avalos ◽  
Shelby Graham ◽  
Daymond R. Parrilla ◽  
...  

ABSTRACT Human immunodeficiency virus (HIV) eradication or long-term suppression in the absence of antiretroviral therapy (ART) requires an understanding of all viral reservoirs that could contribute to viral rebound after ART interruption. CD4 T cells (CD4s) are recognized as the predominant reservoir in HIV type 1 (HIV-1)-infected individuals. However, macrophages are also infected by HIV-1 and simian immunodeficiency virus (SIV) during acute infection and may persist throughout ART, contributing to the size of the latent reservoir. We sought to determine whether tissue macrophages contribute to the SIVmac251 reservoir in suppressed macaques. Using cell-specific quantitative viral outgrowth assays (CD4-QVOA and MΦ-QVOA), we measured functional latent reservoirs in CD4s and macrophages in ART-suppressed SIVmac251-infected macaques. Spleen, lung, and brain in all suppressed animals contained latently infected macrophages, undetectable or low-level SIV RNA, and detectable SIV DNA. Silent viral genomes with potential for reactivation and viral spread were also identified in blood monocytes, although these cells might not be considered reservoirs due to their short life span. Additionally, virus produced in the MΦ-QVOA was capable of infecting healthy activated CD4s. Our results strongly suggest that functional latent reservoirs in CD4s and macrophages can contribute to viral rebound and reestablishment of productive infection after ART interruption. These findings should be considered in the design and implementation of future HIV cure strategies. IMPORTANCE This study provides further evidence that the latent reservoir is comprised of both CD4+ T cells and myeloid cells. The data presented here suggest that CD4+ T cells and macrophages found throughout tissues in the body can contain replication-competent SIV and contribute to rebound of the virus after treatment interruption. Additionally, we have shown that monocytes in blood contain latent virus and, though not considered a reservoir themselves due to their short life span, could contribute to the size of the latent reservoir upon entering the tissue and differentiating into long-lived macrophages. These new insights into the size and location of the SIV reservoir using a model that is heavily studied in the HIV field could have great implications for HIV-infected individuals and should be taken into consideration with the development of future HIV cure strategies.


1983 ◽  
Vol 31 (2) ◽  
pp. 155 ◽  
Author(s):  
GR Singleton

A 2-year program monitored the spatial organization, genetic structure and turnover rate of an unconfined commensal colony of mice. Four demes (social breeding units) were identified; each usually consisted of one or two males and two or three females. Demes were detected simultaneously in adjoining cages of an aviary (one deme per cage). Movement between demes was rare and the life span of a deme ranged from 2 to 7 months. The adult members of each deme had genotypes compatible to the majority of the young captured in the respective cage of the aviary at the time of residence of the deme. Taken in isolation, these results suggest that social behaviour would have a major impact on the genetic structure of the aviary population. When viewed over the main breeding season, the short life span of a deme and the genetic differences between demes indicate that social organization probably had only a temporary effect on the genetic composition of the aviary population.


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