Monoclonal antibodies to chick intestinal receptors for 1,25-dihydroxyvitamin D3. Interaction and effects of binding on receptor function

Monoclonal antibodies, developed against the chick intestinal receptor for 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), were characterized with respect to their interaction with this protein and for their effects on the polypeptide's hormone-binding and nuclear-binding functions. Antibodies, internally labeled with [35S]methionine, react directly with hormone-labeled receptor, as identified by comigration of both isotopes during sedimentation on hypertonic 10-30% sucrose gradients. Antibodies bound both the unoccupied and occupied forms of the receptor, the latter with equilibrium dissociation constants of 10(-10)-10(-11) M at 4 degrees C. Excess antibody, added to unoccupied receptors prior to incubation with 1,25(OH)2D3, did not affect the receptor's apparent affinity for the hormone (Kd approximately equal to 6 X 10(-11) M). In contrast, all three antibodies, complexed with occupied receptors, significantly reduced the extent of the receptor's association with isolated nuclei (48-64% inhibition). This inhibition most likely represents a general reduction in the affinity of the protein for nuclei under the conditions tested, since the affinity of the occupied 1,25(OH)2D3 receptor for DNA, as well as the ionic strength necessary to elute receptor from both cation and anion exchange resins was significantly reduced by prior incubation with excess antibody. These findings suggest that the epitopes for each of the three monoclonal antibodies may be located in or near the DNA or nuclear binding domain of the 1,25(OH)2D3 receptor. Taken cumulatively, these results indicate that the monoclonal immunoreagents utilized here should prove useful in delineating important biochemical features of this unique sterol hormone receptor.     

Conformist learning in nine-spined sticklebacks' foraging decisions

Theoretical analyses have reported that in most circumstances where natural selection favours reliance on social learning, conformity (positive frequency-dependent social learning) is also favoured. These findings suggest that much animal social learning should involve a copy-the-majority strategy, yet there is currently surprisingly little evidence for conformist learning among animals. Here, we investigate this possibility in the nine-spined stickleback (Pungitius pungitius) by manipulating the number of demonstrator fish at two feeders, one rich and one poor, during a demonstration phase and evaluating how this affects the likelihood that the focal fish copy the demonstrators'' apparent choices. As predicted, we observed a significantly increased level of copying with increasing numbers of demonstrators at the richer of the two feeders, with copying increasing disproportionately, rather than linearly, with the proportion of demonstrators at the rich foraging patch. Control conditions with non-feeding demonstrators showed that this was not simply the result of a preference for shoaling with larger groups, implying that nine-spined sticklebacks copy in a conformist manner.     

Structural and Dynamic Properties of Allergen and Non-Allergen Forms of Tropomyosin

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Rearing environment influences boldness and prey acquisition behavior,and brain and lens development of bull trout

Animals reared in barren captive environments exhibit different developmental trajectories and behaviors than wild counterparts. Hence, the captive phenotypes may influence the success of reintroduction and recovery programs for threatened and endangered species. We collected wild bull trout embryos from the Metolius River Basin, Oregon and reared them in differing environments to better understand how captivity affects the bull trout Salvelinus confluentus phenotype. We compared the boldness and prey acquisition behaviors and development of the brain and eye lens of bull trout reared in conventional barren and more structurally complex captive environments with that of wild fish. Wild fish and captive reared fish from complex habitats exhibited a greater level of boldness and prey acquisition ability, than fish reared in conventional captive environments. In addition, the eye lens of conventionally reared bull trout was larger than complex reared captive fish or same age wild fish. Interestingly, we detected wild fish had a smaller relative cerebellum than either captive reared treatment. Our results suggest that rearing fish in more complex captive environments can create a more wild-like phenotype than conventional rearing practices. A better understanding of the effects of captivity on the development and behavior of bull trout can inform rearing and reintroduction programs though prediction of the performance of released individuals.     

Tissue-enhanced plasma proteomic analysis for disease stratification in amyotrophic lateral sclerosis

Background

It is unclear to what extent pre-clinical studies in genetically homogeneous animal models of amyotrophic lateral sclerosis (ALS), an invariably fatal neurodegenerative disorder, can be informative of human pathology. The disease modifying effects in animal models of most therapeutic compounds have not been reproduced in patients. To advance therapeutics in ALS, we need easily accessible disease biomarkers which can discriminate across the phenotypic variants observed in ALS patients and can bridge animal and human pathology. Peripheral blood mononuclear cells alterations reflect the rate of progression of the disease representing an ideal biological substrate for biomarkers discovery.

Methods

We have applied TMTcalibrator?, a novel tissue-enhanced bio fluid mass spectrometry technique, to study the plasma proteome in ALS, using peripheral blood mononuclear cells as tissue calibrator. We have tested slow and fast progressing SOD1G93A mouse models of ALS at a pre-symptomatic and symptomatic stage in parallel with fast and slow progressing ALS patients at an early and late stage of the disease. Immunoassays were used to retest the expression of relevant protein candidates.

Results

The biological features differentiating fast from slow progressing mouse model plasma proteomes were different from those identified in human pathology, with only processes encompassing membrane trafficking with translocation of GLUT4, innate immunity, acute phase response and cytoskeleton organization showing enrichment in both species. Biological processes associated with senescence, RNA processing, cell stress and metabolism, major histocompatibility complex-II linked immune-reactivity and apoptosis (early stage) were enriched specifically in fast progressing ALS patients. Immunodetection confirmed regulation of the immunosenescence markers Galectin-3, Integrin beta 3 and Transforming growth factor beta-1 in plasma from pre-symptomatic and symptomatic transgenic animals while Apolipoprotein E differential plasma expression provided a good separation between fast and slow progressing ALS patients.

Conclusions

These findings implicate immunosenescence and metabolism as novel targets for biomarkers and therapeutic discovery and suggest immunomodulation as an early intervention. The variance observed in the plasma proteomes may depend on different biological patterns of disease progression in human and animal model.