Summer movement patterns of Arctic lemmings (Lemmus sibiricus and Dicrostonyx groenlandicus)

Several measures of movement based on livetrapping data were used to compare summer movement patterns of Lemmus sibiricus and Dicrostonyx groenlandicus in northern Canada. Distances moved by individuals of both species were greater when populations were intermediate in size than at high or low density. At intermediate density, males of both species moved farther than females. Seasonal movement patterns of the two species were similar. Coincident with reproductive periods in late July and late August, distances moved decreased in both species. Increased movements of both species followed periods of reproductive activity and also occurred at the end of each summer. These latter movements are related to seasonal changes in patterns of habitat use and diet in each species. These results suggest that dispersal is an important determinant of seasonal patterns of population change in both L. sibiricus and D. groenlandicus.

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Seasonal Movement PAtterns of the Eastern Grey Kangaroo in Southern Queensland

Wildlife Research ◽

10.1071/wr9820373 ◽

1982 ◽

Vol 9 (3) ◽

pp. 373 ◽

Cited By ~ 12

Author(s):

GJE Hill

Keyword(s):

Soil Moisture ◽

Seasonal Changes ◽

Movement Patterns ◽

Distribution Patterns ◽

Faecal Pellet ◽

Soil Moisture Storage ◽

Seasonal Movement ◽

Grey Kangaroo ◽

Pellet Counts ◽

Moisture Storage

A 2-y study was made of seasonal movement patterns of the eastern grey kangaroo, Macropus giganteus Shaw, in the Warwick district of south-eastern, and the Bollon district of south-western, Queensland. Faecal pellet counts were used to obtain indices of kangaroo usage of cleared country adjacent to cover. Kangaroos were sensitive to changes in forage status, particularly pasture phenology. As quality and quantity of forage reserves declined, animals made progressively greater use of cleared areas. This resulted in marked seasonal changes in distribution patterns. Of the variables quantified (rainfall, soil moisture storage and pasture growth), rainfall provided the best correlations with kangaroo usage of cleared country, explaining 55% (P = 0.002) of the variation in distribution at Warwick and 91% (P = 0.001) of that at Bollon.

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Transport of Apolipoprotein B-Containing Lipoproteins through Endothelial Cells Is Associated with Apolipoprotein E-Carrying HDL-Like Particle Formation

International Journal of Molecular Sciences ◽

10.3390/ijms19113593 ◽

2018 ◽

Vol 19 (11) ◽

pp. 3593 ◽

Cited By ~ 3

Author(s):

Hong Yang ◽

Ningya Zhang ◽

Emmanuel Okoro ◽

Zhongmao Guo

Keyword(s):

Endothelial Cells ◽

Apolipoprotein B ◽

Density Lipoprotein ◽

High Density ◽

Low Density ◽

Endothelial Monolayer ◽

Aortic Endothelial Cells ◽

Pass Through ◽

Intermediate Density ◽

Current Report

Passage of apolipoprotein B-containing lipoproteins (apoB-LPs), i.e., triglyceride-rich lipoproteins (TRLs), intermediate-density lipoproteins (IDLs), and low-density lipoproteins (LDLs), through the endothelial monolayer occurs in normal and atherosclerotic arteries. Among these lipoproteins, TRLs and IDLs are apoE-rich apoB-LPs (E/B-LPs). Recycling of TRL-associated apoE has been shown to form apoE-carrying high-density lipoprotein (HDL)-like (HDLE) particles in many types of cells. The current report studied the formation of HDLE particles by transcytosis of apoB-LPs through mouse aortic endothelial cells (MAECs). Our data indicated that passage of radiolabeled apoB-LPs, rich or poor in apoE, through the MAEC monolayer is inhibited by filipin and unlabeled competitor lipoproteins, suggesting that MAECs transport apoB-LPs via a caveolae-mediated pathway. The cholesterol and apoE in the cell-untreated E/B-LPs, TRLs, IDLs, and LDLs distributed primarily in the low-density (LD) fractions (d ≤ 1.063). A substantial portion of the cholesterol and apoE that passed through the MAEC monolayer was allotted into the high-density (HD) (d > 1.063) fractions. In contrast, apoB was detectable only in the LD fractions before or after apoB-LPs were incubated with the MAEC monolayer, suggesting that apoB-LPs pass through the MAEC monolayer in the forms of apoB-containing LD particles and apoE-containing HD particles.

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Regulation of low-density-lipoprotein metabolism in the rat

Biochemical Journal ◽

10.1042/bj2340493 ◽

1986 ◽

Vol 234 (2) ◽

pp. 493-496 ◽

Cited By ~ 12

Author(s):

S Bhattacharya ◽

S Balasubramaniam ◽

L A Simons

Keyword(s):

Low Density Lipoprotein ◽

Ldl Receptor ◽

Lipoprotein Metabolism ◽

Density Lipoprotein ◽

Hormonal Control ◽

Low Density ◽

Experimental Conditions ◽

Synthetic Rate ◽

Catabolic Rate ◽

Intermediate Density

The mechanism of regulation of plasma low-density-lipoprotein (LDL) metabolism in the rat was studied under a number of experimental conditions. LDL clearance and uptake in the liver was measured after intravenous pulse injection of [14C]sucrose-labelled LDL alone or in combination with reductively methylated [3H]sucrose-labelled LDL. Hyperthyroid rats showed a significant increase in fractional catabolic rate (FCR) and the proportion of LDL degraded in the liver, whereas the synthetic rate of LDL increased by 50%. Receptor-mediated clearance increased 2-fold. Hypothyroid rats showed a significant increase in LDL concentration. The FCR and proportion of LDL degraded in the liver were decreased significantly. Receptor-mediated clearance was also reduced. Cholesterol feeding increased chylomicron, very-low-density-and intermediate-density-lipoprotein cholesterol concentrations, but there was no change in the LDL concentration, FCR or the synthetic rate of LDL. Cholestyramine feeding did not induce changes in the kinetic parameters. These results indicate that, in the rat, the hepatic LDL-receptor pathway is under hormonal control, whereas cholesterol and cholestyramine feeding have no demonstrated effect on LDL metabolism.

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Delayed clearance of very low density and intermediate density lipoproteins with enhanced conversion to low density lipoprotein in WHHL rabbits.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.79.18.5693 ◽

1982 ◽

Vol 79 (18) ◽

pp. 5693-5697 ◽

Cited By ~ 124

Author(s):

T. Kita ◽

M. S. Brown ◽

D. W. Bilheimer ◽

J. L. Goldstein

Keyword(s):

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Low Density ◽

Intermediate Density

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The disappearance rate of human versus rat intermediate density lipoproteins from rat liver perfusion

Biochemistry and Cell Biology ◽

10.1139/o91-079 ◽

1991 ◽

Vol 69 (8) ◽

pp. 537-543 ◽

Cited By ~ 1

Author(s):

Robert Dupras ◽

Louise Brissette ◽

Paul D. Roach ◽

Sylvain Begin ◽

André Tremblay ◽

...

Keyword(s):

Liver Perfusion ◽

Density Lipoprotein ◽

Low Density Lipoproteins ◽

Low Density ◽

Disappearance Rate ◽

Very Low Density Lipoproteins ◽

Rat Liver Perfusion ◽

Heparin Plasma ◽

Intermediate Density

The aim of this work was to compare the disappearance rate of human and rat intermediate density lipoproteins (IDL) using the rat liver perfusion system. Human and rat IDL were produced in vitro by incubating human or rat very low density lipoproteins (VLDL) with either rat post-heparin plasma (method I) or a resolubilized isopropanol precipitate of rat post-heparin plasma (method II). With both methods, the degree of triacylglycerol lipolysis was approximately 55%. The different preparations of IDL were labelled with 125I and added to perfusates of rat livers. The disappearance rates of 125I-labelled IDL were monitored by measuring the radioactivity associated with apolipoprotein (apo) B in the perfusate during a 15-min period. Both human and rat IDL prepared with method I had an increased apoE to apoC ratio as compared with their native counterparts. Furthermore, human IDL had a significantly higher apoE to apoC ratio than rat IDL. However, when IDL were produced in the absence of exchangeable apolipoproteins (method II), no change in the apoE to apoC ratios was observed for the transformation of VLDL to IDL and the ratios were similar for human and rat IDL. Despite these differences, human IDL were always removed at a lower rate than rat IDL. The only striking difference between the two types of IDL made by method II was that the apoB100 to apoB48 ratio was considerably higher in human than in rat IDL. These results suggest that the apoB100 to apoB48 ratio is likely to be responsible for the observed differences in liver uptake between rat and human IDL.Key words: very low density lipoproteins, intermediate density lipoproteins, low density lipoproteins, hepatic lipoprotein receptors, intermediate density lipoprotein uptake, in vitro lipolysis, very low density lipoprotein remnants, apolipoproteins.

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Oestrous activity in three subtropical sheep breeds in Upper Egypt and response to long-day light treatment

The Journal of Agricultural Science ◽

10.1017/s0021859600076243 ◽

1991 ◽

Vol 116 (1) ◽

pp. 139-143 ◽

Cited By ~ 5

Author(s):

A. M. Aboul-Naga ◽

H. Mansour ◽

M. B. Aboul-Ela ◽

M. T. Mousa ◽

Ferial Hassan ◽

...

Keyword(s):

Breeding Season ◽

Seasonal Changes ◽

Nile Delta ◽

Reproductive Activity ◽

Light Treatment ◽

Continuous Exposure ◽

Upper Egypt ◽

Sheep Breeds ◽

Awassi Sheep ◽

Long Day

SUMMARYOestrous activity in local Rahmani and Ossimi sheep and imported subtropical Awassi sheep at different times of the year in Upper Egypt and the effect of continuous exposure to long-day conditions from July till December on this activity was studied in 1986. The three breeds differed substantially in oestrous activity but differences did not seem to be directly related to latitude of origin. Rahmani ewes from the Nile Delta were mostly cyclic all year round; the percentage coming to oestrus each month never fell below 70%. Ossimi ewes originating from mid-Egypt had a very long breeding season; 74% had an anoestrous period of 68·8 days (v. 27% for Rahmani ewes). All Awassi ewes, except one, had an anoestrous period of 96·5 days on average.Awassi ewes also showed more response to continuous exposure to long days (14 h) than Ossimi ewes, seen in a shorter reaction interval and a greater decrease in the percentage of ewes coming into oestrus (27 and 90% in control and treated Awassi ewes, respectively). The results indicated that changes in daylength, although small in subtropical regions, may be a major factor controlling seasonal changes in reproductive activity in subtropical sheep breeds, the more seasonal breed being more responsive to changes in daylength. The possibility of selection within these breeds for continuous reproductive activity is also indicated.

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Overwintering strategies of migratory birds: a novel approach for estimating seasonal movement patterns of residents and transients

Journal of Applied Ecology ◽

10.1111/1365-2664.12655 ◽

2016 ◽

Vol 53 (4) ◽

pp. 1035-1045 ◽

Cited By ~ 13

Author(s):

Viviana Ruiz-Gutierrez ◽

William L. Kendall ◽

James F. Saracco ◽

Gary C. White

Keyword(s):

Migratory Birds ◽

Movement Patterns ◽

Seasonal Movement ◽

Novel Approach

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Growth, Biomass Production and Root Development of Chinese fir in Relation to Initial Planting Density

Forests ◽

10.3390/f10030236 ◽

2019 ◽

Vol 10 (3) ◽

pp. 236 ◽

Cited By ~ 5

Author(s):

Taimoor Farooq ◽

Wenjing Wu ◽

Mulualem Tigabu ◽

Xiangqing Ma ◽

Zongming He ◽

...

Keyword(s):

Spatial Distribution ◽

Biomass Production ◽

Stand Density ◽

Tree Height ◽

Root Systems ◽

Chinese Fir ◽

High Density ◽

Planting Density ◽

Low Density ◽

Intermediate Density

Chinese fir (Cunninghamia lanceolata (Lamb) Hook) is a commercially valuable timber species that is widely planted in southern China and accounts for 6.1% of the global plantation forests. However, appropriate planting density that ensures high plantation productivity is largely unexplored in this species. The aim of the study was to examine tree growth, biomass production, and its allocation among different organs in relation to initial planting density, and to examine whether planting density has an impact on root development. Mortality, diameter at breast height and tree-height of all trees were determined and measured in wider (2.36 × 2.36 m), intermediate (1.83 × 1.83 m) and narrow (1.44 × 1.44 m) spacing with stand density of 1450 trees ha−1, 2460 trees ha−1 and 3950 trees ha−1, respectively. In each stand, three plots of 20 × 20 m at a distance of 500 m were delineated as the sampling unit. Biomass was determined by destructive sampling of trees in each stand and developing allometric equations. Root morphological traits and their spatial distribution were also determined by carefully excavating the root systems. The results showed an increase in diameter of trees with decreasing stand density while tree height was independent of stand density. Biomass production of individual trees was significantly (p < 0.05) less in high-density stand (32.35 ± 2.98 kg tree−1) compared to low-density stand (44.72 ± 4.96 kg tree−1) and intermediate-density stand (61.35 ± 4.78 kg tree−1) while stand biomass production differed significantly in the order of intermediate (67.63 ± 5.14 t ha−1) > high (57.08 ± 3.13 t ha−1) > low (27.39 ± 3.42 t ha−1) stand density. Both average root length and root volume were significantly (p < 0.05) lower in the high-density stand than stands with low and intermediate density. Analysis of spatial distribution of root systems revealed no overlap between roots of neighboring trees in the competition zone in low-density stand, a subtle overlap in the intermediate density stand and larger overlap in the high-density stand. It can be concluded that better growth and biomass production in intermediate density stand could be explained by better root structural development coupled with minimal competition with understory vegetation and between trees; thus intermediate stand density can be optimal for sustaining long-term productivity and may reduce the management cost in the early phase of the plantation.

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