Ecological Aspects of a Wood Turtle, Glyptemys insculpta, Population at the Northern Limit of its Range in Québec

As part of a conservation research initiative, a population of Wood Turtles (Glyptemys insculpta) at the northern limit of its range was studied to ascertain characteristics of its demographics, morphometrics, density, mortality, feeding, and mating activities. Turtles were captured and marked during the activity period in 1996 and 1997. In addition, 20 individuals were radio-tracked weekly. A total of 188 turtles was captured and the size of the population in the study area was estimated at 238 turtles. The estimated population density based on this calculation is 0.44 turtles/ha. This is less than other studies indicating that population densities are greater in southern populations. Turtles from this population were large (carapace length of males=214.5 ± 4.21 mm, females=201.1 ± 10.88 mm) which supports the hypothesis that turtle size is negatively correlated with number of frost free days. The sex ratio was not significantly different from 1:1. Juvenile turtles accounted for 31.4% of the population. Observations of feeding habits support the claim that Wood Turtles are opportunistic omnivores. Of the 35 mating or courtship events observed, 77 % occurred in the fall and half of them between 11:00 and 13:00. Although limb and tail injuries and parasites were observed on many turtles, no dead turtles were observed. This last result, combined with the high rate of recruitment and even sex ratio suggests that this population is stable, making it an ideal population with which to make comparisons with other studies in areas where the species could be in decline

Seasonal variation in the incidence of preeclampsia and eclampsia in tropical climatic conditions

<p>Abstract</p> <p>Background</p> <p>Observational studies have demonstrated various correlations between hypertensive disorders of pregnancy and different weather parameters. We aim to study if a correlation exists between the incidence of eclampsia and pre-eclampsia and various weather parameters in the tropical coastal city of Mumbai which has the distinction of having relatively uniform meteorological variables all throughout the year, except for the monsoon season.</p> <p>Methods</p> <p>We retrospectively analysed data from a large maternity centre in Mumbai, India over a period of 36 months from March 1993 to February 1996, recording the incidence of preeclampsia and eclampsia. Meteorological data was acquired from the regional meteorological centre recording the monthly average temperature, humidity, barometric pressure and rainfall during the study period. Study period was then divided into two climate conditions: monsoon season (June to August) and dry season September to May. The incidence of preeclampsia and eclampsia and the meteorological differences between the two seasons were compared.</p> <p>Results</p> <p>Over a 36-month period, a total of 29562 deliveries were recorded, of which 1238 patients developed preeclampsia (4.18%) and 34 developed eclampsia (0.11%). The incidence of preeclampsia did not differ between the monsoon and the dry season (4.3% vs. 4.15%, p = 0.5). The incidence of eclampsia was significantly higher in the monsoon (0.2% vs. 0.08%, p = 0.01). The monsoon was significantly cooler (median maximum temperature 30.7°C vs. 32.3°C, p = 0.01), more humid (median relative humidity 85% vs. 70%, p = 0.0008), and received higher rainfall (median 504.9 mm vs. 0.3 mm, p = 0.0002) than the rest of the year. The median barometric pressure (1005 mb) during the monsoon season was significantly lower than the rest of the year (1012 mb, p < 0.0001).</p> <p>Conclusion</p> <p>In the tropical climate of Mumbai, the incidence of eclampsia is significantly higher in monsoon, when the weather is cooler and humid with a lower barometric pressure than the rest of the year. This effect is not seen with preeclampsia. This strengthens the association of low temperature and high humidity with triggering of eclampsia.</p

ATTITUDES OF CANADIANS TOWARD THE CONTROL OF RED-WINGED BLACKBIRDS

Each year across Canada, millions of dollars of damage to agricultural crops can be attributed to vertebrate pests. Estimates for 1975 indicated that approximately $240,000,000 damage was incurred by agricultural pests (Solman et al. 1975). Worldwide impact of these pests must certainly be staggering, especially during the current trend of rising production costs and demand for food. In Canada and the United States, pest control programs may be attacked by increaseingly active and vocal environmental groups. Recently, the killing of blackbirds (Icteridae) and starlings (Sturnus vulgaris) in Kentucky and Tennessee evoked strong objection (Graham 1976, 1978; Jackson 1976). As a result, politically sensitive civil servants may feel justified in avoiding programs which involve the killing of vertebrate pests. While decision-making within the government is subject to public scrutiny and criticism, prior knowledge of public attitudes toward potential policies may enable public servants to make acceptable decisions regarding wildlife management (Hendee and Potter 1973) Unfortunately, there is a paucity of sociological research addressing the question of public attitudes toward pest control. Arthur et al. (1977) assessed the attitudes of Americans toward the conflict between environmentalists and livestock ranchers regarding the killing of coyotes (Canis Iatrans), and Buys (1975) examined the attitudes of New Mexico ranchers toward coyotes and coyote control. From these studies it was found that ranchers harbor attitudes which are resistant to the implementation of non- lethal control techniques, and that, in general, the public was more concerned about the humaneness and species specificity of control than cost effectiveness. These facts are particularly relevant to the controversy concerning red-winged blackbird (Agelaius phaeniceus) damage to corn (Zea mays) in southwestern Quebec, where members of the agricultural communities have encouraged the use of lethal control measures to decrease blackbird populations (Weatherhead et al. these proceedings). The objectives of this paper are to examine and assess the attitudes of Canadians vis- a-vis agricultural pest control and to include Quebec farmers’ evaulations of the blackbird population, crop damage and control techniques. To achieve these objectives, the results from 3 surveys conducted during the period 1975-1978 were examined. The first was a study of the attitudes of Quebeckers toward environmentally-related outdoor activities and agricultural pest control (Clark 1979). Next, a survey of Quebec farmers was used to locate roosts, obtain crop-damage estimates and assess attitudes toward blackbirds and their control. And third, a random survey of Canadians examined attitudes toward the control of red-winged blackbirds which damage crops and suggested several management strategies

Ligand-induced endocytosis of the asialoglycoprotein receptor : evidence for heterogeneity in subunit oligomerization

The hepatic asialoglycoprotein receptor, a noncovalent hetero-oligomer of two subunits, is a constitutively cycling endocytic receptor. However, the ligand asialoorosomucoid caused downregulation of up to 40% of surface binding sites and a twofold increase in internalization rate. This was not the result of receptor crosslinking, since monovalent ligands had the same effect. Ligand binding thus appears to transmit a signal to the cytosolic portion of the receptor not unlike in signaling receptors. The two subunits were endocytosed at different average rates lower than that of ligand, indicating heterogeneity in oligomer formation and potentially in ligand specificity

Introduction to the 4th International Workshop on Adaptive Case Management and Other Non-workflow Approaches to BPM (AdaptiveCM 2015)

Front Matter.</p

High-affinity ligand binding to subunit H1 of the asialoglycoprotein receptor in the absence of subunit H2

The hepatic asialoglycoprotein receptor is a hetero-oligomer composed of two homologous subunits. The specificity and affinity of ligand binding depends on the number and spatial arrangement of several galactose-binding sites within the receptor complex. Previous studies indicated that both subunits are required for high-affinity ligand binding, i.e. for the simultaneous interaction with three galactose residues within an N-linked glycan. However, we found that asialoorosomucoid (ASOR) and asialofetuin (ASF) bind to transfected COS-7 cells expressing subunit H1 in the absence of the second subunit H2. ASOR binding occurred with a dissociation constant of approximately 40 nM, approximately four-times higher than the Kd of ASOR binding to the hetero-oligomeric receptor. Normalized to the amount of H1 expressed, approximately 10-times fewer binding sites were produced by H1 alone. A glycopeptide with a single tri-antennary N-linked glycan purified from ASF bound to the hetero-oligomeric receptor, but did not bind detectably to H1-expressing COS-7 cells. H1 is thus unable to simultaneously recognize all three galactose residues in a glycan. From this, we conclude that, at a sufficiently high density of H1 on the cell surface, high-affinity binding of ASOR and ASF is the result of two or more glycans interacting with H1 oligomers with low affinity in a bivalent manner

Mechanism of endoplasmic reticulum retention of mutant vasopressin precursor caused by a signal peptide truncation associated with diabetes insipidus

Autosomal dominant neurohypophyseal diabetes insipidus is caused by mutations in the gene encoding the vasopressin precursor protein, prepro-vasopressin-neurophysin II. We analyzed the molecular consequences of a mutation (DeltaG227) recently identified in a Swiss kindred that destroys the translation initiation codon. In COS-7 cells transfected with the mutant cDNA, translation was found to initiate at an alternative ATG, producing a truncated signal sequence that was functional for targeting and translocation but was not cleaved by signal peptidase. The mutant precursor was completely retained within the endoplasmic reticulum. The uncleaved signal did not affect folding of the neurophysin portion of the precursor, as determined by its protease resistance. However, formation of disulfide-linked aggregates indicated that it interfered with the formation of the disulfide bond in vasopressin, most likely by blocking its insertion into the hormone binding site of neurophysin. Preventing disulfide formation in the vasopressin nonapeptide by mutation of cysteine 6 to serine was shown to be sufficient to cause aggregation and retention. These results indicate that the DeltaG227 mutation induces translation of a truncated signal sequence that cannot be cleaved but prevents correct folding and oxidation of vasopressin, thereby causing precursor aggregation and retention in the endoplasmic reticulum

The oligomerization domain of the asialoglycoprotein receptor preferentially forms 2:2 heterotetramers in vitro

The human hepatic asialoglycoprotein receptor is a noncovalent hetero-oligomer composed of two homologous subunits, H1 and H2, with an as yet unknown stoichiometry. Ligand specificity and binding affinity depend on the arrangement of the subunits in the complex. An 80-amino acid segment connecting the transmembrane and the carbohydrate binding domains contains heptad repeats characteristic of alpha-helical coiled coil structure. We expressed and purified corresponding peptides, H1S and H2S, and confirmed by circular dichroism spectroscopy that they can assume alpha-helical conformation. Oxidative cross-linking of amino-terminal cysteines generated specific covalent oligomers, indicating that separately H1S forms trimers and H2S tetramers. Upon mixing, covalent heterotetramers were formed with a preferred stoichiometry of 2 H1S and 2 H2S peptides. These results suggest that the stalk segments of the receptor subunits oligomerize to constitute an alpha-helical coiled coil stalk on top of which the carbohydrate binding domains are exposed for ligand binding. We propose that the functional asialoglycoprotein receptor is a 2:2 heterotetramer