Intense grazing by voles (Microtus pennsylvanicus) and its effect on habitat quality

1993 ◽  
Vol 71 (9) ◽  
pp. 1823-1830 ◽  
Author(s):  
Jean-Marie Bergeron ◽  
Louise Jodoin
Keyword(s):  
Total Phenolics ◽  
Growth Period ◽  
Microtus Pennsylvanicus ◽  
Nonstructural Carbohydrates ◽  
Meadow Voles ◽  
Qualitative And Quantitative ◽  
Total Nonstructural Carbohydrates ◽  
Biomass Yields ◽  
Defensive Mechanisms ◽  
Quantitative Changes

Meadow voles (Microtus pennsylvanicus) were housed in fenced plots to simulate the effects of crowding on qualitative and quantitative changes of vegetation. Within one summer they reached density levels equivalent to 1000–1300 voles/ha and were removed from the plots during the fall. Biomass yields were estimated during fall and the following spring to assess the immediate effects of grazing and plant recovery before the new growth period. Significant reductions in yields of green biomass were registered in fall (15%) and in the following spring (52%) in the grazed plots. Dead matter was also reduced by intense grazing (> 7%). Biomass quality was estimated from measures of protein, total phenolics, and total nonstructural carbohydrates (TNC). Protein and phenolics in green biomass samples did not vary in the fall and spring collections but TNC varied significantly between grazed and ungrazed plots during both sampling periods. Intense grazing by voles during one summer of high density imposes quantitative changes on meadows that are still noticeable the following spring while most of the nutritive constituents of vegetation are affected little by grazing. These results support the idea that voles do not induce defensive mechanisms in heavily grazed plants.

An FTIR study of Pseudomonas aeruginosa PAO1 biofilm growth and dispersion. An improved ATR method for studying biofilms: the C–H stretch spectral region

Biofilms ◽  
2004 ◽  
Vol 1 (3) ◽  
pp. 157-163 ◽  
Author(s):  
J. Pink ◽  
T. Smith-Palmer ◽  
T. J. Beveridge ◽  
D. A. Pink
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Subsequent Development ◽  
Growth Period ◽  
Flow Cell ◽  
Biofilm Growth ◽  
Chemical Difference ◽  
Qualitative And Quantitative ◽  
Quantitative Changes ◽  
Biofilm Development ◽  
First Time

Pseudomonas aeruginosa PAO1 was grown on 40° ZnSe and 40° AMTIR® (Amorphous Material Transmitting Infrared Radiation, Ge33As12Se55) internal reflection elements in a thermostatted flow cell. Information about the chemistry of the biofilm development was obtained using Fourier transform infrared spectroscopy. The weakly absorbing C–H stretching region of the infrared spectrum was measured for the first time and revealed qualitative and quantitative changes not evident in the amide region studied by previous investigators. There is a chemical difference between the early growth period and subsequent development of the biofilm.

Comparison of food habits and of nutrients in the stomach contents of summer- and winter-trapped voles (Microtus pennsylvanicus)

1994 ◽  
Vol 72 (1) ◽  
pp. 183-187 ◽  
Author(s):  
Jean-Marie Bergeron ◽  
Louise Jodoin
Keyword(s):  
Food Habits ◽  
Total Phenolics ◽  
Stomach Contents ◽  
Microtus Pennsylvanicus ◽  
Fecal Matter ◽  
Plant Parts ◽  
Total Nonstructural Carbohydrates ◽  
Fat Reserves ◽  
Quality Diet ◽  
Foraging Constraints

Meadow voles (Microtus pennsylvanicus) have low fat reserves in winter. Since plant parts with high nutritive values are less abundant at this period, we hypothesize that voles must select different items or face a lower quality diet than during summer. Food habits determined from epidermal plant fragments of fecal matter showed that summer- and winter-trapped voles were using the same plant species though in somewhat different amounts. Nutritive constituents evaluated from stomach contents varied significantly by season. Stomach contents of winter-trapped voles had lower levels of protein and total phenolics and higher levels of total nonstructural carbohydrates. Forage quality ratios involving protein/total phenolics did not vary between seasons. These results suggest that overwintering voles of this study, trapped during low density, did not face obvious nutritive constraints. However, voles living under more crowded conditions could still face foraging constraints.

Expression of laminin and beta-1 integrin in embryonic, neonatal, and adult rat heart

1991 ◽  
Vol 49 ◽  
pp. 182-183
Author(s):  
R.L. Price ◽  
T.K. Borg ◽  
L. Terracio ◽  
M. Nakagawa
Keyword(s):  
Temporal Expression ◽  
Qualitative And Quantitative ◽  
Adult Rat ◽  
Cytoplasmic Face ◽  
Extracellular Matrix Components ◽  
Basement Membrane Component ◽  
Beta 1 Integrin ◽  
Quantitative Changes ◽  
Cytoskeletal Elements ◽  
External Face

Little is known about the temporal expression of extracellular matrix components (ECM) and its receptors during development of the heart. Recent reports have shown that ECM components undergo both qualitative and quantitative changes during development, and it is believed that ECM components are important in the regulation of cell migration and cell:cell and cell:ECM recognition and adhesion.Integrins are transmembrane glycoproteins which bind several ECM components on their external face and cytoskeletal elements on the cytoplasmic face. Laminin is a basement membrane component which has been recognized as an important site for cell adhesion. Both the integrins and laminin are expressed early in development and continue to be expressed in the adult heart. With their documented roles in cell recognition, and cell:cell and cell:ECM migration and adhesion these proteins appear to be important components in development of the heart, and their temporal expression may play a pivotal role in morphogenesis and myofibrillogenesis of the heart.

Functional MR Imaging of the Motor Cortex in Active and Passive Movement: Qualitative and Quantitative Changes

2002 ◽  
Vol 46 (5) ◽  
pp. 425
Author(s):  
Ki Bong Yu ◽  
Myung Kwan Lim ◽  
Hyung Jin Kim ◽  
Jun Soo Byun ◽  
Young Kook Cho ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Mr Imaging ◽  
Passive Movement ◽  
Qualitative And Quantitative ◽  
Functional Mr Imaging ◽  
Quantitative Changes

STRUCTURE AND DYNAMICS OF ENVIRONMENTAL PARAMETERS OF HUMAN INTESTINAL MICROBIOME IN DIFFERENT CLIMATIC AND ECOLOGICAL ZONES OF ST. PETERSBURG

2020 ◽  
pp. 31-36
Author(s):  
Bugero N.V. ◽  
Ilyina N.A. ◽  
Aleksandrova S.M.
Keyword(s):  
Environmental Parameters ◽  
Intestinal Microbiome ◽  
Ecological Niches ◽  
Horizontal Structure ◽  
Ecological Zones ◽  
Qualitative And Quantitative ◽  
Symbiotic Relationships ◽  
Structure And Dynamics ◽  
Quantitative Changes ◽  
Micro Organisms

In order to understand the structure and dynamics of symbiotic relationships of human intestinal biotope micro-organisms, taxonomic constancy indices, the degree of contagion of the biocenosis under study and floristic significance were investigated, which made it possible to detect qualitative and quantitative changes in the microecology of the biotope being studied in persons living in different ecologically heterogeneous territories of Saint Petersburg. The contagiosity index estimated the distribution of species in space. Persons living in the ecologically disadvantaged Kirov district of the city have been found to show a reliable increase in this indicator for the obligate microflora: bifido and lacto bacteria, intestinal columns and bacteroids, compared to the resort district, which is considered a relatively favourable area for residence. On the contrary, there has been a reliable decrease in this indicator in the group of opportunistic micro-organisms (fungi of the genus Candida, staphylococcus, clostridium, etc.), resulting in the liberation of ecological niches successfully occupied by transient flora. This ratio reveals an imbalance of participation in the horizontal structure of the intestine ecosystem of the main symbiotes and representatives of the transient flora. To analyse the structure of symbiotic relationships, the constancy indices that form the microflora of the individuals of the groups studied were investigated. The analysis of the data obtained suggested that the dominant species in both groups were optional-anaerobic bifido and lactobacteria and oblique-anaerobic bacteroids. It should be noted, however, that in the residents of the dysfunctional Kirovsky district, against the background of the reduced constancy of the normal flora, opportunistic micro-organisms have entered. The floral significance index was also declining in the obligate flora of this group and increased for opportunistic species. Thus, the study of the environmental characteristics of the intestinal biotope using different ecological parameters for persons living in different technogenic load regions of St. Petersburg has shown that in the Kirov district with an unfavourable environmental situation there are compensated qualitative and quantitative changes in the intestinal microbiocenosis, resulting in a change in the hierarchy in the overall structure of micro-organisms.

Influence of short-term atmospheric CO2 enrichment on growth, allocation patterns, and biochemistry of black spruce seedlings at different stages of development

1989 ◽  
Vol 19 (6) ◽  
pp. 773-782 ◽  
Author(s):  
Michel A. Campagna ◽  
Hank A. Margolis
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Black Spruce ◽  
Production Cycle ◽  
Nonstructural Carbohydrates ◽  
Short Term ◽  
Stages Of Development ◽  
Greenhouse Production ◽  
Total Nonstructural Carbohydrates

Black spruce seedlings (Piceamariana Mill.) were exposed to either elevated (1000 ppm) or ambient (340 ppm) atmospheric CO2 levels at different stages of seedling development over a winter greenhouse production cycle. Seedlings germinated in early February and were placed in CO2 chambers for either 3 or 6 weeks during March, April, May, or August. Total seedling biomass increased under high CO2 conditions for the March, April, and May stages of development, but showed no significant response in August. The greater part of the CO2 response occurred during the second 3 weeks of exposure in March and April but during the first 3 weeks of exposure in May. In September, those seedlings exposed to CO2 in April and May had 30 and 14%, respectively, greater biomass than control seedlings, but seedlings from the other stages of development no longer had significant differences remaining from the CO2 treatment. This suggests that it could be very efficient to give a short well-timed CO2 pulse at the beginning of the production cycle in hopes of producing a size difference that is maintained throughout the remainder of the greenhouse production cycle under ambient levels of CO2. Short-term exposure to elevated CO2 also increased the ratio of shoot dry weight to total height for the March, April, and May stages of development. The ratio of total nonstructural carbohydrates to free amino acids was negatively correlated (r2 = 0.98) with the allocation of new growth between shoots and roots as measured by the allocation coefficient, k (milligrams shoot growth per milligrams root growth). As seedlings developed along their seasonal growth cycle, ratios of total nonstructural carbohydrates to free amino acids increased and the values for k decreased. The effect of CO2 enrichment on these two factors is discussed. Monitoring total nonstructural carbohydrate and free amino acid concentrations in foliage could have potential as a method to predict the percentage of carbon allocated to root systems of entire forest stands as well as of individual tree seedlings.

Changes in levels of foliar carbohydrates and myo-inositol before premature leaf senescence of Populus nigra induced by a mixture of O3 and SO2

1996 ◽  
Vol 74 (6) ◽  
pp. 965-970 ◽  
Author(s):  
R. C. Fialho ◽  
J. Bücker
Keyword(s):  
Air Pollution ◽  
Leaf Senescence ◽  
Populus Nigra ◽  
Continuous Exposure ◽  
Nonstructural Carbohydrates ◽  
Progressive Decline ◽  
Total Nonstructural Carbohydrates ◽  
Leaf Yellowing ◽  
Premature Leaf Senescence ◽  
Early Indication

Specimens of Populus nigra L. cv. Loenen exhibit premature leaf senescence when exposed for a few weeks to realistic air pollution. In this study, the changes in levels of foliar carbohydrates and myo-inositol (MI) due to 30 ± 1 nL/L O3 + 12 ± 1 nL/L SO2 from the onset of exposure to the occurrence of premature abscission is presented. Petioles and laminae of the 12 oldest leaves were separately analysed on days 0, 4, 8, 12, 16, 20, 22, and 32 of continuous exposure, which was performed in open-top chambers (OTC). On days 8 to 12, clearly prior to yellowing (starting on day 22), total nonstructural carbohydrates (TNC; starch + raffinose + sucrose + glucose + fructose + MI) in the fumigated laminae exceeded that in controls by about 30%. This increase was due to higher amounts of different soluble forms, while starch remained unaltered. From day 20 onwards, the level of TNC in the fumigated laminae progressively fell below that in controls. This decrease was due to a progressive decline in starch, which had started on day 16 and was dominating, although glucose and raffinose increased significantly. In the petioles, starch, sucrose, and glucose decreased because of fumigation with the occurrence of leaf yellowing, while raffinose increased. In contrast, MI in the petioles progressively accumulated directly on exposure until leaf yellowing occurred. The results are discussed in terms of the "general adaption syndrome" of H. Selye (1936. Nature (London), 138: 32). The marked MI response in petioles is concluded to be an early indication of phytorelevant O3 + SO2 pollution. Keywords: air pollution, carbohydrates, myo-inositol, pigments, Populus nigra L., senescence, stress.

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