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The Mississippi River Valley and its basin have undergone major changes since the Pliocene. Pliocene ancestral Mississippi River headwaters drained southern Alberta, Saskatchewan, Manitoba, and southwestern Ontario in a Pliocene drainage basin that was at least 30% greater than the modern Mississippi River basin. This large drainage basin is supported by Pliocene paleodrainage in Alberta and Saskatchewan and paleochannel analyses of Pliocene Mississippi River meander bends preserved in the Pliocene Mississippi River terrace sediments of the Upland Complex near Memphis, Tennessee. Near Memphis, the Pliocene discharge is calculated to have been six to eight times the discharge of the modern Mississippi River. The Pliocene Mississippi River drainage flowed east across Alberta and Saskatchewan, south across Paleozoic sedimentary rocks that covered the Canadian Shield in Manitoba and Ontario, and into North Dakota and South Dakota along the ancestral Red River. Early Pleistocene continental glaciation removed the sedimentary rocks covering the current Canadian Shield region of Manitoba and Ontario. Sea level declines of 120 m during the Pleistocene eroded central and southern Mississippi River Valley sediments of the Mississippi Embayment, and the base of Pliocene Upland Complex terrace remnants (Pliocene Mississippi River sediments) is now 70 m above the base of Holocene Mississippi River floodplain sediments near Memphis. This 70-m elevation difference is attributed to a +25-m Pliocene sea level and 45 m of Mississippi River Valley isostatic uplift caused by the Pleistocene denudation of the Mississippi River Valley. The erosion and isostatic uplift of the Mississippi Valley have influenced the state of stress in the valley and are in part responsible for reactivating Cambrian basement faults of the Reelfoot Rift and consequent earthquakes of the New Madrid seismic zone. Continuing Holocene glacial isostatic uplift of Manitoba and Ontario is returning the drainage of these provinces to their Pliocene southerly flow. We believe the north-flowing Red River, Lake Winnipeg, and southern 200 km of the Nelson River will reverse to a southerly flow to join the Mississippi River system between 6 and 8 ka if Canadian continental glaciation does not return. [ABSTRACT FROM AUTHOR]

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The article presents a study on Mesomycetozoea within the order of Dermocystida (D.) and link of the organism with mortality event in yellow perch Perca flavescens (Mitchill) in Ontario, Canada. It mentions of organisms infected with species D. percae and D. fennicum, like common perch, Perca fluviatilis Linnaeus, in Finland, Estonia and Germany.

A brief period of drawdown can stimulate wetland productivity and enhance the attractiveness of a site for breeding Trumpeter Swans (Cygnus buccinator) by providing a nutrient pulse. Drawdown of a pond in Aurora, Ontario, lasting about 8 weeks in late summer and fall 2009 followed by re-flooding increased the abundance of invertebrates, especially snails, in the following year. This response was ephemeral, lasting 1 year. Wild Trumpeter Swans and their cygnets responded by selective feeding the year after drawdown, despite the risk of predation by Snapping Turtles (Chelydra serpentina). There was a strong correlation between the feeding activity of two cygnets and the local abundance of snails in the pond in 2010. The nutritional content, especially protein, calcium, phosphorus, and magnesium, of a variety of abundant foods satisfied the requirements for skeletal growth and development and was higher than that of available commercial duck grower rations. The responsive feeding behaviours of the cygnets are typical of specific appetitive behaviour and suggest that swans rapidly exploit unpredictable nutrient fluxes in their local environment. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Medical Imaging & Radiation Sciences is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Flavobacterium psychrophilum is the causative agent of bacterial coldwater disease (BCWD) and rainbow trout fry syndrome. BCWD has a considerable economic impact on aquaculture operations in Ontario, Canada, and our limited understanding of the population structure and epidemiology of F. psychrophilum isolates is an impediment to the development of improved management strategies. Seventy-five 16S rRNA gene and gyr polymerase chain reaction positive isolates of F. psychrophilum that had been collected over a 16-year period from farmed salmonids with tail rot, necrotic myositis, and osteochondrosis were characterized morphologically, biochemically, and genotypically. Although the isolates were homogeneous by preliminary biochemical and phenotypic characterization, two distinct biovars were found by API ZYM testing. As well, four restriction pattern types were detected by 16S rRNA polymerase chain reaction - restriction fragment length polymorphism analysis and there was a significant (P < 0.001) correlation between biovar I and digestion with MaeIII and between biovar II and digestion with MnlI or no site (P < 0.05). Further heterogenity was detected by sequence analysis of a 194 bp stem loop 3 region of rRNA. Nine sequence types were identified; 40/46 biovar I isolates were sequence type “a”, while 21/32 biovar II isolates belonged to either sequence type “c” or “d”. More than one biovar and genotype was identified among the strains recovered from separate fish sampled from three groups of rainbow trout (Oncorhynchus mykiss) experiencing BCWD mortality events. No association was found between genotype or biovar and type of disease. Taken together, these data suggest that F. psychrophilum from Ontario can be grouped into two major lineages based on biovar and 16S rRNA polymorphisms, and although three major strain types were most frequently isolated in this study, it appears that the population of F. psychrophilum with pathogenic potential is quite heterogeneous. Flavobacterium psychrophilum est l’agent causal de la maladie des eaux froides et du « rainbow trout fry syndrome ». La maladie des eaux froides a un impact économique considérable sur l’aquaculture en Ontario, Canada, et notre connaissance limitée de la structure de la population et de l’épidémiologie des isolats de F. psychrophilum nous empêche de développer de meilleures stratégies de contrôle. Soixante-quinze isolats de F. psychrophilum positifs en PCR pour les gènes de l’ARNr 16S et gyr ont été recueillis pendant 16 ans chez des salmonidés d’élevage présentant une pourriture de la queue, une myosite nécrotique et une ostéochondrose, et ils ont été caractérisés morphologiquement, biochimiquement et génotypiquement. Même si les isolats étaient homogènes selon la caractérisation biochimique et phénotypique préliminaire, deux biovars distincts ont été trouvés par un test API ZYM. De même, quatre types de patrons de restriction ont été détectés par une PCR-RFLP de l’ARNr 16S, une corrélation significative (P < 0.001) étant trouvée entre le biovar I et le patron de digestion avec MaeIII, et entre le biovar II et le patron de digestion avec MnlI ou en absence de sites (P < 0.05). Une plus grande hétérogénéité a été détectée par des analyses de séquence de la région tige-boucle 3 de 194 pb de l’ARNr. Neuf types de séquences ont été identifiés; 40/46 isolats du biovar I appartenaient au type « a » alors que 31/32 isolats du biovar II appartenaient aux types de séquence « c » ou « d ». Plus d’un biovar et génotype a été identifié parmi les souches recueillies de poissons différents échantillonnés à partir de trois groupes de truites arc-en-ciel (Oncorhynchus mykiss) où une mortalité par la maladie des eaux froides avait été observée. Aucune association n’a été trouvée entre le génotype, le biovar et le type de maladie. En somme, ces résultats suggèrent que la population de F. psychrophilum de l’Ontario peut être divisée en deux lignées principales selon le polymorphisme des biovars et de l’ARNr 16S, et, même si trois principaux types de souches ont été plus fréquemment isolés lors de cette étude, il semble que la population de F. psychrophilum possédant un potentiel pathogène soit assez hétérogène. [ABSTRACT FROM AUTHOR]

Greater Prairie Chickens started their range expansion from Wisconsin about 1900. They reached Sault Ste. Marie, Ontario, by 1925 and completed colonization of Manitoulin Island by 1945. In the fall of 1932, an irruption of Northern Sharp-tailed Grouse from the Hudson Bay Lowlands occurred. Residents of Manitoulin distinguished the two species and reported the presence of "square-tails" and "sharp-tails" in the winter of 1932-1933. There is no specimen evidence or verbal reports that Northern Sharp-tailed Grouse reached Michigan during that irruption. Prairie Sharp-tailed Grouse were in the northern peninsula of Michigan by 1930. In 1941, Michigan Department of Natural Resources made a planting of 37 Prairie Sharp-tailed Grouse on Drummond Island. Thence they spread east and the first lek was found at the west end of Manitoulin Island in 1952. By 1960, these birds had virtually colonized the whole island. Development of a hybrid index from the morphology of specimens of skins and skeletons from Manitoulin indicated that more than 50% of all birds in the 1960s were hybrids. In Michigan, less than 1% of the birds necropsied or checked in hunters' bags were hybrid. It seems likely that ethological isolation broke down on Manitoulin Island. The booming display of the Prairie Chicken and the tail rattling display of the Sharp-tailed Grouse can be broken down into their component parts. They appear to be homologous to five discrete displays of the Spruce Grouse, grouped in different patterns in each of the two lek species. There was little hybridization between Prairie Sharp-tailed Grouse and Prairie Chickens that had lived sympatrically for thousands of years. Northern Sharp-tailed Grouse had probably never lived sympatrically with Prairie Chickens and the evolution of the perception of species distinctions may not have evolved to the point where hybridization was restricted to a rare event. [ABSTRACT FROM AUTHOR]

I made comparisons among populations of Greater Prairie-Chickens, Sharp-tailed Grouse and their hybrids on Manitoulin Island of pinnae length, breast, flank and tail feather patterns, tail graduations, wing chord, and skeletal characteristics. Estimates of the proportion of hybrids from these individual characters ranged from 32% to 60%. Lek behaviour of hybrids was a mixture of the patterns of the parent species. The colour of the booming sacks varied and displayed the range between the parent species. There was a tendency with time for the characters of Prairie Chickens to decline coincident with an increase in Sharp-tailed Grouse characters. Both Prairie Chickens and Sharp-tailed Grouse are lek species in which an alpha mate may consummate most of the the matings. The speed with which morphological change took place in Manitoulin Island is to be expected where a non-random mating system of this kind prevails. [ABSTRACT FROM AUTHOR]

To assess the impacts of different types of human activity on the development of resistant bacteria in the feces of wild small mammals, we compared the prevalences and patterns of antimicrobial resistance and resistance genes in generic Escherichia coli and Salmonella enterica isolates from fecal samples collected from wild small mammals living in four environments: swine farms, residential areas, landfills, and natural habitats. Resistance to antimicrobials was observed in E. coli isolates from animals in all environments: 25/52 (48%) animals trapped at swine farms, 6/69 (9%) animals trapped in residential areas, 3/20 (15%) animals trapped at landfills, and 1/22 (5%) animals trapped in natural habitats. Animals trapped on farms were significantly more likely to carry E. coli isolates with resistance to tetracycline, ampicillin, sulfisoxazole, and streptomycin than animals trapped in residential areas. The resistance genes sul2, aadA, and tet(A) were significantly more likely to be detected in E. coli isolates from animals trapped on farms than from those trapped in residential areas. Three S. enterica serotypes (Give, Typhimurium, and Newport) were recovered from the feces of 4/302 (1%) wild small mammals. All Salmonella isolates were pansusceptible. Our results show that swine farm origin is significantly associated with the presence of resistant bacteria and resistance genes in wild small mammals in southern Ontario, Canada. However, resistant fecal bacteria were found in small mammals living in all environments studied, indicating that environmental exposure to antimicrobials, anti-microbial residues, resistant bacteria, or resistance genes is widespread. [ABSTRACT FROM AUTHOR]