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  • Canadian Science Publishing  (25)
  • English  (25)
  • 2000-2004  (25)
  • 1
    Online Resource
    Online Resource
    Intergradation and origins of subspecies of the turtle Chrysemys picta : morphological comparisons
    Canadian Science Publishing ; 2001
    In:  Canadian Journal of Zoology Vol. 79, No. 3 ( 2001-03-01), p. 485-498
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 79, No. 3 ( 2001-03-01), p. 485-498
    Abstract: We present morphological data on the four subspecies of painted turtles (Chrysemys picta) from 20 states in the U.S.A. and three provinces in Canada, and from localities within them that are removed from reported zones of intergradation. The characters used are those of Hartman (1958), which have been routinely used in subsequent studies: the extent of plastral patterning (here quantified by image analysis), the degree of misalignment of carapacial scutes, and the width of the light anterior margins of the second lateral scutes. Our purposes are to present descriptive baseline data for each subspecies for use in comparisons with the results of past and future studies of intergradation, and to critique the oft-accepted theory of Bleakney (1958) regarding the evolutionary origins of the current subspecies, particularly C. p. marginata. Data are given for C. p. bellii from 5 states ranging from Minnesota to New Mexico, for C. p. dorsalis from 3 states (Arkansas, Louisiana, and Mississippi), for C. p. marginata from 4 localities (Ontario, Michigan, Indiana, and Ohio), and for C. p. picta from 11 localities from Nova Scotia to Georgia. We find that (i) a "pure" picta does not exist; there is marginata influence throughout picta's range, particularly at the extremes; (ii) similarities exist that group dorsalis with picta; (iii) there is a north-south cline of reduced scute alignment in picta; (iv) there is a north-south cline of increasing extent of the plastral pattern in bellii; (v) the question of which subspecies first reached New England after the Wisconsinan glaciation remains unresolved, but it was likely not picta; (vi) there is no compelling reason to accept or reject Bleakney's theory of the distribution of painted turtle subspecies at the height of the Wisconsinan glaciation or his conjecture that marginata arose as in intergrade of bellii and dorsalis; in fact, it could be argued that if marginata is a hybrid, it could be a hybrid of picta and bellii.
    Type of Medium: Online Resource
    ISSN: 0008-4301 , 1480-3283
    URL: Article
    DOI: 10.1139/z01-001
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2001
    detail.hit.zdb_id: 1490831-1
    SSG: 12
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  • 2
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    Levels of ACC and related compounds in exudate and extracts of canola seeds treated with ACC deaminase-containing plant growth-promoting bacteria
    Canadian Science Publishing ; 2001
    In:  Canadian Journal of Microbiology Vol. 47, No. 4 ( 2001-04-01), p. 368-372
    Details
    In: Canadian Journal of Microbiology, Canadian Science Publishing, Vol. 47, No. 4 ( 2001-04-01), p. 368-372
    Abstract: It was previously proposed that plant growth-promoting bacteria that possess 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase could utilize ACC that is present in the exudate of germinating canola seeds. The uptake and cleavage of ACC by these bacteria would lower the level of ACC, and thus ethylene within the plant, and reduce the extent of its inhibition on root elongation. To test part of the above mentioned model, ACC levels were monitored in canola seed tissues and exudate during germination. Lower amounts of ACC were present in the exudate and tissues of seeds treated with the plant growth-promoting bacterium Enterobacter cloacae CAL3, than in control seeds treated with MgSO 4 . The ACC-related compounds, α- and γ-aminobutyric acids, both known to stimulate ethylene production, were also measured in the canola seed exudate and tissues. Approximately the same levels of α-aminobutyric acid were present in the exudates of the bacterium-treated seeds and the control seeds, but the amount of α-aminobutyric acid was lower in the tissues of the bacterium-treated seeds than in the control seeds. Smaller quantities of γ-aminobutyric acid were seen in both the exudate and tissues of the E. cloacae CAL3-treated seeds than in the control seeds.Key words: ACC ethylene, canola, seed extract, seed exudate, plant growth-promoting bacteria.
    Type of Medium: Online Resource
    ISSN: 0008-4166 , 1480-3275
    URL: Article
    DOI: 10.1139/w01-014
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2001
    detail.hit.zdb_id: 280534-0
    detail.hit.zdb_id: 1481972-7
    SSG: 12
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  • 3
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    Influence of Physical Training on Plasma Leptin in Obese Youths
    Canadian Science Publishing ; 2003
    In:  Canadian Journal of Applied Physiology Vol. 28, No. 3 ( 2003-06-01), p. 382-396
    Details
    In: Canadian Journal of Applied Physiology, Canadian Science Publishing, Vol. 28, No. 3 ( 2003-06-01), p. 382-396
    Abstract: Little is known about the effects of different intensities of physical training on plasma leptin. This study examined the effect of two intensities of physical training on leptin in obese teenagers, and explored correlates at baseline and in response to 8 months of physical training. The participants were 55 obese youths 12-16 years of age who completed both baseline and posttesting. The youths were randomized to engage in lifestyle education only (LSE), moderate-intensity physical training and LSE, or high-intensity physical training and LSE. Baseline leptin was positively associated with fat mass. Girls had higher leptin levels at lower levels of fasting insulin than boys. The 8-mo physical training doses prescribed to obese teenagers did not result in significant group differences in mean change in leptin, although there was large variability in individual response. The change in leptin was inversely associated with baseline leptin and change in cardiovascular fitness. Diet, physical activity level, visceral adiposity, and glucose concentrations were not associated with leptin, neither at baseline nor in response to physical training. At baseline, total fat mass rather than visceral adiposity was associated with higher leptin levels. Over the 8-mo intervention period, regardless of group membership, youths who had the lowest increase in cardiovascular fitness tended to have the highest increase in leptin. Key words: pediatrics, obesity, insulin, cardiovascular fitness
    Type of Medium: Online Resource
    ISSN: 1066-7814
    URL: Article
    DOI: 10.1139/h03-028
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2003
    SSG: 31
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  • 4
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    Leaf trichome morphology and density in West African Trema spp. (Ulmaceae: Celtidoideae)
    Canadian Science Publishing ; 2000
    In:  Canadian Journal of Botany Vol. 78, No. 1 ( 2000-03-07), p. 34-39
    Details
    In: Canadian Journal of Botany, Canadian Science Publishing, Vol. 78, No. 1 ( 2000-03-07), p. 34-39
    Abstract: Leaf trichome morphology and density are described for three species belonging to the genus Trema from West Africa: T. africana (Planch.) Blume, T. orientalis (L.) Blume, and T. nitens (Hook. & Planch.) Blume. Leaves of specimens collected in West Africa were observed using scanning electron microscopy. Unicellular trichome morphology was assessed, and a 3 × 3 two-way contingency table analysis showed dependence between the trichome type and species identity. Density of unicellular and multicellular trichomes on both leaf surfaces as well as the number of cells composing the stalk of multicellular trichomes were measured and subjected to nonparametric analysis of variance. Kruskal-Wallis tests yielded significant results (p 〈 0.05) among the three species for all characters except unicellular trichome density on the adaxial leaf surface. Wilcoxon two-sample tests showed that all species were different, except for the density of multicellular trichomes on the abaxial leaf surface where densities in T. africana and T. orientalis were not significantly different. The number of cells composing the stalk of multicellular trichomes was significantly different among each species on the adaxial leaf surface, but on the abaxial one, T. africana and T. orientalis exhibited no significant differences. The value of these characters in the discrimination between the three species is discussed.Key words: Trema spp., Ulmaceae, West Africa, leaf trichomes, morphology, density.
    Type of Medium: Online Resource
    ISSN: 0008-4026
    URL: Article
    DOI: 10.1139/b99-157
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2000
    detail.hit.zdb_id: 218116-2
    detail.hit.zdb_id: 1481926-0
    SSG: 12
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  • 5
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    The 5S rRNA gene units in the native New World annual Hordeum species (Triticeae: Poaceae)
    Canadian Science Publishing ; 2000
    In:  Canadian Journal of Botany Vol. 78, No. 12 ( 2000-12-01), p. 1590-1602
    Details
    In: Canadian Journal of Botany, Canadian Science Publishing, Vol. 78, No. 12 ( 2000-12-01), p. 1590-1602
    Abstract: We have employed a polymerase chain reaction (PCR) based approach to amplify 5S rDNA sequences from 20 accessions representing five Hordeum species native to the Americas. Sequence analysis of 88 clones revealed three sets of orthologous sequences in Hordeum pusillum Nutt. and two sets in the other four species. The long H1 unit class, previously known in Hordeum bulbosum L., Hordeum marinum L. s.l., Hordeum murinum L. s.l., Hordeum spontaneum Boiss., and Hordeum vulgare L., was found also in Hordeum depressum (Scribner & Smith) Rydberg and in H. pusillum; however, the majority of the sequences fell within two new classes of orthologous sequences. Sequences of the long H2 unit class were found in four species but not in H. depressum. Sequences of the long Y2 unit class were found in all five species. The long H2 and long Y2 unit classes appear to be unique to this group of five, mostly annual, North and South American species. Cladistic analysis of the orthologous sequences from the species with the long H1 unit class places the long H1 sequence of Hordeum flexuosum Steudel in the same clade with H. murinum, whereas H. depressum is more closely related to the perennial species, Hordeum bogdanii Wilenski and H. bulbosum. This association differs from previously described species relationships and it may be that the gene tree differs from the species tree. A cladistic analysis of paralogous sequences of the two new unit classes defined in this study together with the long H1, the long Y1 and the long X2 unit classes uncovered in previous work in Hordeum, was performed. Based upon these analyses, we hypothesize that the possible order of divergence was first the division into two branches leading to the long H1 unit class and the long H2 unit class; the lineage leading to the long H2 class was further divided to give rise to branches leading to the long Y1, the long Y2 and the long X2 classes.Key words: 5S rDNA, genomes, haplomes, unit classes, Hordeum, Triticeae.
    Type of Medium: Online Resource
    ISSN: 0008-4026
    URL: Article
    DOI: 10.1139/b00-131
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2000
    detail.hit.zdb_id: 218116-2
    detail.hit.zdb_id: 1481926-0
    SSG: 12
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  • 6
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    A comparison of the 5S rDNA diversity in the Hordeum brachyantherum californicum complex with those of the eastern Asiatic Hordeum roshevitzii and the South American Hordeum cordobense (Triticeae: Poaceae)
    Canadian Science Publishing ; 2002
    In:  Canadian Journal of Botany Vol. 80, No. 7 ( 2002-07-01), p. 752-762
    Details
    In: Canadian Journal of Botany, Canadian Science Publishing, Vol. 80, No. 7 ( 2002-07-01), p. 752-762
    Abstract: Amplification of the 5S rDNA gene by the polymerase chain reaction, followed by cloning and sequencing, was used to generate data from 23 seed accessions of Hordeum brachyantherum Nevski, Hordeum californicum Covas et Stebbins, Hordeum cordobense Bothmer, Jacobsen et Nicora, and Hordeum roshevitzii Bowden. One hundred and fourteen clones were analyzed, resulting in the detection of four different 5S DNA unit classes. Three of them, long H1, long H2, and long Y2, had been previously reported. The long H3 class, described for the first time, is present only in H. roshevitzii but can be grouped with previously unassigned units of Hordeum bulbosum L. and Hordeum spontaneum C. Koch. Based upon the analyses of 5S rDNA sequences, we found that (i) the long H2 unit class was not found in the Asiatic H. roshevitzii and therefore may be restricted to the American species, (ii) there is no strong support that H. brachyantherum and H. californicum are worthy of species recognition, and (iii) cladistic analysis of the consensus sequences of the four paralogous unit classes demonstrated that long Y2 is the most distant from the three long H classes.Key words: 5S DNA gene, Hordeum, unit classes.
    Type of Medium: Online Resource
    ISSN: 0008-4026
    URL: Article
    DOI: 10.1139/b02-057
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2002
    detail.hit.zdb_id: 218116-2
    detail.hit.zdb_id: 1481926-0
    SSG: 12
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  • 7
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    Quantification of soil redistribution and sediment budget in a Canadian watershed from fallout caesium-137 ( 137 Cs) data
    Canadian Science Publishing ; 2002
    In:  Canadian Journal of Soil Science Vol. 82, No. 4 ( 2002-11-01), p. 423-431
    Details
    In: Canadian Journal of Soil Science, Canadian Science Publishing, Vol. 82, No. 4 ( 2002-11-01), p. 423-431
    Abstract: The intensification and specialization of agriculture that took place in the past decades have resulted in soil and water degradation in several areas of eastern Canada. Most studies on soil erosion in Quebec have been conducted at the experimental plot scale. Although this approach generates precise data, extrapolation at the field or watershed scale is difficult. In this study, caesium-137 ( 137 Cs) was used to investigate the spatial extent and severity of soil erosion for an 80-ha watershed in Southeastern Quebec (cultivated area = 75 ha). Soil samples were collected based on a 25 (30 m grid and revealed soil redistribution rates ranging from -20 to +12 Mg ha -1 yr -1 . From radiocaesium measurements, it was estimated that the experimental watershed experienced an average loss of 3.0 Mg ha -1 yr -1 with net sediment export of 2.8 Mg ha -1 yr -1 and a sediment delivery ratio of 93%. Snowmelt erosion is believed to have played an important role in the soil redistribution in this small watershed. Changing sampling strategy was tested (50 x 60 m and 100 x 120 m grid rather than 25 x 30 m) and only minor changes were noticed on soil erosion and sediment production estimates, when samples corresponding to the 50 x 60 m grid were used. Key words: Caesium-137 ( 137 Cs), watershed, water erosion, snowmelt erosion, sampling strategy
    Type of Medium: Online Resource
    ISSN: 0008-4271 , 1918-1841
    URL: Article
    DOI: 10.4141/S02-016
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2002
    detail.hit.zdb_id: 2017003-8
    detail.hit.zdb_id: 417254-1
    SSG: 13
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  • 8
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    Current, reconstructed past, and projected future status of brook trout ( Salvelinus fontinalis ) streams in Virginia
    Canadian Science Publishing ; 2000
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 57, No. 7 ( 2000-07-01), p. 1515-1523
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 57, No. 7 ( 2000-07-01), p. 1515-1523
    Abstract: Southern Appalachian streams host a rich diversity of fishes, but the Southern Appalachian Assessment concluded that 70% of stream locations showed significant fish community degradation, partly due to acid deposition. About 40% of total Southern Appalachian trout stream length occurs in Virginia. Our research in Shenandoah National Park, Virginia, has documented both chronic and episodic acidification in streams and brook trout (Salvelinus fontinalis) mortality during acid episodes. Here, we analyze a representative sample of 60 Virginia brook trout streams on noncarbonate bedrock with minimal human disturbance in their watersheds. Of more than 300 such streams in Virginia, only about 50% are currently suitable for brook trout, based on their acidification status. For the population of brook trout streams to which this analysis applies, model-based projections indicate that continued sulfate deposition at 1991 levels will result in about 70 additional streams becoming chronically acidic and unsuitable for brook trout. A 40% reduction will result in about 48 additional chronically acidic streams. Even a 70% reduction will likely result in about 15 additional streams becoming acidified. We conclude that reductions in sulfate deposition greater than 70% (relative to 1991 levels) are needed to prevent more brook trout stream losses in Virginia.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/f00-086
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2000
    detail.hit.zdb_id: 7966-2
    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
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  • 9
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    Determination of 1-aminocycopropane-1-carboxylic acid (ACC) to assess the effects of ACC deaminase-containing bacteria on roots of canola seedlings
    Canadian Science Publishing ; 2001
    In:  Canadian Journal of Microbiology Vol. 47, No. 1 ( 2001-01-01), p. 77-80
    Details
    In: Canadian Journal of Microbiology, Canadian Science Publishing, Vol. 47, No. 1 ( 2001-01-01), p. 77-80
    Abstract: Previously, it was proposed that plant growth-promoting bacteria that possess the enzyme, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, can reduce the amount of ethylene produced by a plant and thereby promote root elongation. To test this model, canola seeds were imbibed in the presence of the chemical ethylene inhibitor, 2-aminoethoxyvinyl glycine (AVG), various strains of plant growth-promoting bacteria, and a psychrophilic bacterium containing an ACC deaminase gene on a broad host range plasmid. The extent of root elongation and levels of ACC, the immediate precursor of ethylene, were measured in the canola seedling roots. A modification of the Waters AccQ*Tag Amino Acid Analysis Method(tm) was used to quantify ACC in the root extracts. It was found that, in the presence of the ethylene inhibitor, AVG, or any one of several ACC deaminase-containing strains of bacteria, the growth of canola seedling roots was enhanced and the ACC levels in these roots were lowered.
    Type of Medium: Online Resource
    ISSN: 0008-4166 , 1480-3275
    URL: Article
    DOI: 10.1139/w00-128
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2001
    detail.hit.zdb_id: 280534-0
    detail.hit.zdb_id: 1481972-7
    SSG: 12
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  • 10
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    Transcriptional regulation of the Enterobacter cloacae UW4 1-aminocyclopropane-1-carboxylate (ACC) deaminase gene ( acdS )
    Canadian Science Publishing ; 2001
    In:  Canadian Journal of Microbiology Vol. 47, No. 4 ( 2001-04-01), p. 359-367
    Details
    In: Canadian Journal of Microbiology, Canadian Science Publishing, Vol. 47, No. 4 ( 2001-04-01), p. 359-367
    Abstract: Based on DNA sequence analysis and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, the region of DNA immediately upstream of the Enterobacter cloacae UW4 ACC deaminase gene (acdS) contains several features that appear to be involved in its transcriptional regulation. In the present study, the 5' upstream region of acdS was cloned into the promoter-probe vector, pQF70, which carries the promoterless luciferase gene (luxAB), and luciferase expression was monitored. The data obtained from studying the expression of the luciferase gene showed that (i) a leucine responsive regulatory protein (LRP)-like protein encoded within the upstream region is located on the opposite strand from acdS under the control of a promoter stronger than the one responsible for acdS transcription, (ii) luciferase gene expression required both ACC and the LRP-like protein, (iii) luciferase expression was increased three-fold under anaerobic conditions, consistent with the involvement of a fumarate-nitrate reduction (FNR)-like regulatory protein box within the upstream region, and (iv) the addition of leucine to the growth medium decreased luciferase activity in the presence of ACC and increased luciferase activity in the absence of ACC, consistent with leucine acting as a regulator of the expression of the LRP-like protein.Key words: plant growth promotion, ethylene, ACC deaminase, regulation, Enterobacter cloacae.
    Type of Medium: Online Resource
    ISSN: 0008-4166 , 1480-3275
    URL: Article
    DOI: 10.1139/w01-009
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2001
    detail.hit.zdb_id: 280534-0
    detail.hit.zdb_id: 1481972-7
    SSG: 12
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