scholarly journals Diversity of Hypoviruses and Other Double-Stranded RNAs in Cryphonectria parasitica in North America

1997 ◽  
Vol 87 (10) ◽  
pp. 1026-1033 ◽  
Author(s):  
Tobin L. Peever ◽  
Yir-Chung Liu ◽  
Michael G. Milgroom

Double-stranded (ds) RNAs in Cryphonectria parasitica were randomly sampled from nine subpopulations in North America using an antibody-based detection system for dsRNA. dsRNA was detected in 166 (28%) of a total of 595 C. parasitica isolates sampled by immunoblotting. Incidence of dsRNA infection within subpopulations ranged from 0% in samples from New Hampshire and Ontario to 100% in County Line, MI. Most of the dsRNAs sampled were approximately 9 to 13 kb in size. dsRNAs from 72 isolates analyzed by probing Northern blots with 32P-labeled dsRNAs were in one of three hybridization groups. One hybridization group was widespread throughout eastern North America, being found in New York, New Jersey, Maryland, West Virginia, Kentucky, and Michigan. These dsRNAs hybridized to dsRNA from the previously described C. parasitica isolate SR2 from Maryland and are referred to as SR2-type dsRNAs. The second hybridization group was found almost exclusively in Michigan. The Michigan dsRNAs cross-hybridized to Cryphonectria hypovirus 3-GH2 (CHV3-GH2) and are referred to as CHV3-type dsRNAs.One dsRNA sampled from Kentucky hybridized to CHV3-type dsRNAs from Michigan. This dsRNA was probably derived from a fungal isolate that had been intentionally released for biological control at this same site 10 years previously and had become established in Kentucky. The third hybridization group was found only in New Jersey. These dsRNAs were much smaller than all other dsRNAs (3 and 5 kb) and were found in all 11 isolates that were probed; two of these isolates also had SR2-type dsRNA in mixed infections. None of the North American dsRNAs hybridized to CHV1 from Europe, even though CHV1 has been released in numerous locations in eastern North America for biological control of chestnut blight. Similarly, no dsRNAs hybridized to CHV2-NB58, a hypovirus found previously in New Jersey. Mixed infections of SR2-type and CHV3-type dsRNAs were found in 13 of 15 isolates from Frankfort, MI, while another nearby subpopulation (County Line) was infected with only CHV3-type dsRNAs. The distribution of dsRNA hybridization groups in C. parasitica thus presents a mixed picture, since one hybridization group is widespread, whereas two others are primarily restricted to smaller geographic areas.

1998 ◽  
Vol 88 (8) ◽  
pp. 811-817 ◽  
Author(s):  
Tobin L. Peever ◽  
Yir-Chung Liu ◽  
Kerong Wang ◽  
Bradley I. Hillman ◽  
Robert Foglia ◽  
...  

Isolates of the chestnut blight fungus, Cryphonectria parasitica, were randomly sampled from 10 subpopulations in China and 8 subpopulations in Japan and screened for the presence of double-stranded (ds) RNA using an immunoblot procedure with a monoclonal antibody specific for dsRNA. The overall incidence of dsRNA in C. parasitica was 2 and 6% in China and Japan, respectively, much lower than the 28% found previously in North American populations. Genetic relatedness of dsRNAs within and among populations in China and Japan was examined using RNA-RNA hybridizations with labeled-dsRNA probes. The majority of Chinese and Japanese dsRNAs were members of a single hybridization group, related to Cryphonectria hypovirus 1 (CHV1) from Europe, and are referred to as CHV1-type dsRNAs. No evidence was obtained for genetic differentiation between CHV1-type dsRNAs sampled in China and Japan. Five Japanese isolates contained two genetically distinct dsRNAs. The larger segments (approximately 12 kilobases [kb]) were members of the CHV1 hybridization group, while the smaller segments (approximately 3 kb) did not hybridize with any known dsRNA from C. parasitica including the 2.7-kb dsRNA from isolate NB631 from New Jersey or dsRNA from isolate RC1 from Michigan. Two small dsRNA segments (approximately 1.8 and 2 kb) from one isolate sampled from Liaoning Province in northeastern China did not hybridize with any of the dsRNA probes tested including several described dsRNAs of similar size from C. parasitica in North America. Three dsRNAs from Anhui Province, China, hybridized to Cryphonectria hypovirus 2 (CHV2)-specific probes and are thus referred to as CHV2-type dsRNAs. Sequence analysis of 1,627 base pairs of these three CHV2-type dsRNAs from Anhui revealed that they were identical to each other in the region sequenced and very closely related to CHV2-NB58, isolated from New Jersey. We speculate that CHV2-NB58 may have been introduced into North America from this part of China. This is the first record of a North American C. parasitica dsRNA that is genetically related to a dsRNA from Asia.


2013 ◽  
Vol 50 (3) ◽  
pp. 315-323 ◽  
Author(s):  
Richard L. Cifelli ◽  
Cynthia L. Gordon ◽  
Thomas R. Lipka

Multituberculates, though among the most commonly encountered mammalian fossils of the Mesozoic, are poorly known from the North American Early Cretaceous, with only one taxon named to date. Herein we describe Argillomys marylandensis, gen. et sp. nov., from the Early Cretaceous of Maryland, based on an isolated M2. Argillomys represents the second mammal known from the Arundel Clay facies of the Patuxent Formation (Lower Cretaceous: Aptian). Though distinctive in its combination of characters (e.g., enamel ornamentation consisting of ribs and grooves only, cusp formula 2:4, presence of distinct cusp on anterobuccal ridge, enlargement of second cusp on buccal row, central position of ultimate cusp in lingual row, great relative length), the broader affinities of Argillomys cannot be established because of non-representation of the antemolar dentition. Based on lack of apomorphies commonly seen among Cimolodonta (e.g., three or more cusps present in buccal row, fusion of cusps in lingual row, cusps strongly pyramidal and separated by narrow grooves), we provisionally regard Argillomys as a multituberculate of “plagiaulacidan” grade. Intriguingly, it is comparable in certain respects to some unnamed Paulchoffatiidae, a family otherwise known from the Late Jurassic – Early Cretaceous of the Iberian Peninsula.


1986 ◽  
Vol 60 (4) ◽  
pp. 965-967
Author(s):  
William F. Koch

Delthyris sculptilis Hall, 1843, from the Middle Devonian Hamilton Group of New York and equivalent rocks elsewhere in eastern North America, has long been assigned to the genus Delthyris or, in certain older studies, to the genus Spirifer. Recent restudy of this brachiopod shows that it belongs to the genus Megakozlowskiella Boucot, 1962. This extends the upper limit of Megakozlowskiella from the Eifelian (Southwood Stage, Onondaga Limestone in New York) to the Givetian (Tioughnioga Stage, Moscow Formation of the Hamilton Group in New York).


2016 ◽  
Vol 9 (1) ◽  
pp. 60-70 ◽  
Author(s):  
David R. Clements ◽  
Todd Larsen ◽  
Jennifer Grenz

AbstractInvasive species with distributions that encompass much of the North American environment often demand a range of management approaches, for several key reasons. Firstly, the North American environment includes a large number of highly variable habitats in terms of climatic, edaphic, and landscape features. Secondly, these regional habitat differences are accentuated by jurisdictions within Canada and the United States, whereby approaches and available resources differ at local, regional, and national scales. Another important consideration is whether an invasive species or complex also possesses genetic variation. All three of these factors render the knotweed complex in North America a highly variable target for management. In this paper we review existing knowledge of the variable nature of knotweed species (Fallopia japonica (Houtt.) Ronse Decr., Fallopia sachalinensis (F. Schmidt ex Maxim) Ronse Decr., and Fallopia × bohemica, (Chrtek and Chrtková) J. P. Bailey in North America, and evaluate how herbicidal, mechanical and biological control measures must account for this genetic variation, as well as accounting for regional differences and the potential northward expansion of knotweed under climate change. The imminent release of the psyllid, Aphalara itadori Shinji as a biological control agent in North America must also navigate regional and genetic differences. Prior European experience dealing with the three knotweed species should prove useful, but additional research is needed to meet the emerging challenge posed by F. × bohemica in North America, including the possibility of glyphosate resistance. Managers also face challenges associated with posttreatment restoration measures. Furthermore, disparities in resources available to address knotweed management across the continent need to be addressed to contain the rapid spread of this highly persistent and adaptable species. Linking practitioners dealing with knotweed “on the ground” with academic research is a crucial step in the process of marshalling all available resources to reduce the rapidly spreading populations of knotweed.


Author(s):  
Lawrence L. Master ◽  
Lynn S. Kutner

“The air was literally filled with pigeons; the light of noonday was obscured as by an eclipse.” So observed John James Audubon, the eminent naturalist and bird artist, of a mass migration of passenger pigeons (Ectopistes migratorius) passing through Kentucky in 1813. For three days the pigeons poured out of the Northeast in search of forests bearing nuts and acorns. By Audubon’s estimate, the flock that passed overhead contained more than I billion birds, a number consistent with calculations made by other ornithologists. As the pigeons approached their roost, Audubon noted that the noise they made “reminded me of a hard gale at sea passing through the rigging of a close-reefed vessel.” Indeed, they were so numerous that by some accounts every other bird on the North American continent was probably a passenger pigeon at the time of European colonization (Schorger 1955). Yet despite this extraordinary abundance, barely 100 years later the last passenger pigeon, a female bird named Martha, died in the Cincinnati Zoo. The vast flocks of passenger pigeons moved around eastern North America, feeding mostly on the fruits of forest trees such as beechnuts and acorns. Two factors conspired to seal their fate. Because of their huge numbers, the birds were easy to hunt, especially at their roosting sites. Hunters were ingenious in developing increasingly efficient ways to slaughter the birds. Armed with sticks, guns, nets, or sulfur fires, hunters swept through the enormous roosting colonies, carting away what they could carry and feeding the remaining carcasses to their pigs. One of these methods, in which a decoy pigeon with its eyes sewn shut was attached to a perch, or stool, gave rise to the term stool pigeon. As the railroads expanded west, enormous numbers could be sent to major urban markets like New York, where pigeons became the cheapest meat available. They were so cheap and abundant that live birds were used as targets in shooting galleries. At the same time that this frontal assault on the pigeons was under way, human settlers were expanding into the interior of the country, clearing large areas of the forests on which the flocks depended for food.


2010 ◽  
Vol 124 (2) ◽  
pp. 179
Author(s):  
Jean-François Ouellet ◽  
Pierre Fradette ◽  
Isabel Blouin

We report the first observations of Barrow's Goldeneyes south of the St. Lawrence estuary in typical breeding habitat during the breeding season. Until recently, the confirmed breeding locations for the species in Eastern North America were all located on the north shore of the Estuary and Gulf of St. Lawrence.


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