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  • Articles  (5)
  • Rat  (3)
  • chemical mimicry  (2)
  • Springer  (5)
  • National Academy of Sciences
  • Wiley
  • Biology  (5)
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  • Articles  (5)
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  • Springer  (5)
  • National Academy of Sciences
  • Wiley
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  • 1
    Electronic Resource
    Electronic Resource
    A new rapid and reproducible homologous immunoradiometric assay for amino-terminal parathyroid hormone in the rat (1995)
    Springer
    Calcified tissue international 56 (1995), S. 83-87 
    Details
    ISSN: 1432-0827
    Keywords: Immunoradiometric assay ; Parathyroid hormone ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Measurement of parathyroid hormone (PTH) in the rat is most often performed with competitive ligand radioimmunoassays (RIA) utilizing heterologous antibodies. We report here the validation of a newly developed homologous immunoradiometric assay (IRMA) for rat PTH. Two different goat antibodies to the amino-terminal sequence of rat PTH are utilized; one is immobilized onto plastic beads to capture the PTH molecules and the other is radiolabeled for detection. To test this new IRMA, 30 Sprague-Dawley rats were randomized into three treatment groups to receive by intraperitoneal injection: (1) saline 1 ml/kg (control); (2) calcium chloride 40 mg/kg (hypercalcemic); and (3) EDTA 300 mg/kg (hypocalcemic). Blood samples were taken at 0, 30, 60, 180, and 300 minutes after administration of the assigned treatment for measurement of ionized calcium (Ca2+) and serum PTH. Most of the variance in PTH levels was found to be due to changes in Ca2+ (r2=0.780, P〈0.0001). There was also a close temporal relationship between the two, with the highest levels of PTH occurring at the same measured time points as the lowest Ca2+, and vice versa. The measured detection limit of the IRMA was 3 pg/ml with intra-and interassay coefficients of variation of 1.74% and 3.07%, respectively. Serial dilutions with pooled rat serum, synthetic rat PTH-(1–34), and synthetic human PTH-(1–34) showed good parallelism with increased specificity for the pooled and synthetic PTH, despite a degree of crossreactivity with hPTH. The assay is able to quantitate rapid changes in PTH, providing all the advantages of IRMA methodology including technical simplicity and speed of performance, and is likely to become a useful tool in investigations of bone, mineral, and renal homeostasis using the rat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298749
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  • 2
    Electronic Resource
    Electronic Resource
    Immunological detection of a cysteine protease in the skin and other tissues (1985)
    Springer
    Cell & tissue research 240 (1985), S. 417-423 
    Details
    ISSN: 1432-0878
    Keywords: Cysteine protease ; Epidermal cells ; Antigen localization ; Cell differentiation ; Antigen distribution ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Monospecific antibody directed to cysteine protease of 2-day-old rat epidermis recently characterized as being different from the proteases previously reported was produced in rabbits. By immunofluorescence microscopy and immunoperoxidase staining with an avidin-biotin-peroxidase method the protease was found to be present in the epidermis of rodents of different ages as well as that of humans, but not in the dermis. The staining in germinative cells was more intense than in cells in the superficial layers. It appeared as irregular patches in the nuclei and stained more diffusely in the cytoplasm where small granular components, strongly stained, were identified. The staining patterns in granular cells showed accumulation of the antigen in a granular form. The morphology and distribution of granules resembled those of keratohyalin-like granules in the nucleus and dense homogenous deposits in the cytoplasm. In cornified cells the reaction product was localized by the plasma membrane where concentration of the dense homogenous deposits occurred, suggesting that the cysteine protease is one component of the unique and characteristic structure of differentiated keratinocytes. In addition, the cysteine protease antigen having the same molecular weight as the epidermal enzyme was detected in liver, kidney and lung indicating a wider tissue distribution of the protease. The significance of the protease in regulation of cellular functions remains to be investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222354
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  • 3
    Electronic Resource
    Electronic Resource
    The highly modified membrane of cornified cells in stratified squamous epithelia: A comparison of heterogenous deposits in keratinized and nonkeratinized epithelia (1987)
    Springer
    Cell & tissue research 249 (1987), S. 331-336 
    Details
    ISSN: 1432-0878
    Keywords: Cell membrane ; Transglutaminase ; Cysteine ; proteinase inhibitor ; Epithelium ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The chemical nature of the thickened plasma membrane of cornified cells in stratified squamous epithelium was investigated in comparison with that in noncornified epithelium. Localizations of transglutaminase, molecular weight 92000 daltons, and detection of epidermal cysteine proteinase inhibitor were effected with a monoclonal antibody and a monospecific rabbit anti-inhibitor immunoglobulin, respectively, directed to the antigens. N-(7-dimethylamino-4-methylcoumarinyl) maleimide was used to demonstrate S-S cross-linking. In all keratinizing epithelia, the enzyme and inhibitor were deposited on membranes of granular cells. S-S bonds were formed in cornification with the appearance of electron-dense material by the inner leaflet. Both enzyme and inhibitors occurred on the corneal epithelium, but S-S linkage and the thickened plasma membrane did not form even at the last stage of maturation. On the other hand, the internal vaginal epithelium in the proestrous stage without keratinization contained the enzyme, but neither inhibitor nor S-S linkage. Both antigens and S-S bonds were detected when keratinization proceeded during estrus. The staining patterns in the epithelium near the vaginal introitus were identical to those in the skin. Cuboidal and simple epithelia exhibited none of those constituents. The findings indicated that heterogenous components contribute to modification of the plasma membrane of cornified cells, but S-S cross-linkages are associated exclusively with formation of the ultrastructurally unique membrane structure. In addition, findings suggested hormonal regulation in the chemical modification of the membrane in estrogen-sensitive internal vaginal epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215516
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  • 4
    Electronic Resource
    Electronic Resource
    Neotropical ant gardens II. Bioassays of seed compounds (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 2993-3013 
    Details
    ISSN: 1573-1561
    Keywords: Ant ; ant-garden ; benzothiazole ; Camponotus ; Hymenoptera ; Formicidae ; chemical mimicry ; epiphyte ; 2-hydroxy-3-methoxybenzene-methanol ; 1-(2-hydroxy-4-methoxyphenyl)ethanone ; 2-hydroxy-6-methyl-benzoic acid ; methyl ester ; 1-(2-hydroxy-6-methylphenyl)ethanone ; 1-(2,4-dihydroxyphenyl)ethanone ; limonene ; 6-methyl-methylsalicylate ; 6-MMS ; seed dispersal ; symbiosis ; tropical forests ; vanillin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A number of volatile compounds occur on the seeds of taxonomically unrelated ant-garden epiphytes in western Amazonia. In field trials in southeastern Peru, we assayed the responses of ant-garden ants (Camponotus femoratus) to these and structurally similar compounds applied to artificial “seeds” made from zeolite molecular sieves. Benzothiazole,2, present on seeds of eight ant-garden epiphytes, repelled ants over the range of concentrations tested, as did 1-(2-hydroxy-6-methylphenyl)ethanone,3, occurring on seeds of six ant-garden epiphytes. 2-Hydroxy-6-methylbenzoic acid, methyl ester (methyl-6-methylsalicylate, 6-MMS),1, found on seeds of at least nine ant-garden epiphytes, was mildly repellent at high concentration, but stimulated excitement, seed handling, and (rarely) seed carrying at lower concentrations. Vanillin,5, a seed compound of four ant-garden epiphytes, and limonene,6, a monoterpene from seeds of three ant-garden epiphytes, both stimulated excitement, alarm, seed handling, and (rarely) seed carrying. Identified from seeds of seven ant-garden epiphytes, 1-(2,4-dihydroxyphenyl)ethanone,4, elicited little or no response. Among 70 compounds tested (mainly aromatic compounds), those found on seeds of ant-garden epiphytes or having structural features in common with such compounds were the most attractive to the ants. Although not present on epiphyte seeds, 2-hydroxy-3-methoxybenzenemethanol,10, consistently stimulated seed transport to the nest in one year, but did so only rarely in subsequent years. Some of the volatile compounds on seeds of ant-garden epiphytes probably play a role in ant attraction to epiphyte seeds, but evidence remains ambiguous. Finally,Ca. femoratus responded to one test compound [1-(2-hydroxy-4-methoxyphenyl)ethanone,60] (absent from epiphyte seeds) by descending from the vegetation to the ground.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00979490
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  • 5
    Electronic Resource
    Electronic Resource
    Neotropical ant gardens (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 1791-1816 
    Details
    ISSN: 1573-1561
    Keywords: Ant ; ant garden ; Hymenoptera ; Formicidae ; Camponotus ; chemical mimicry ; citronellol ; convergent evolution ; epiphyte ; mellein ; methyl 6-methylsalicylate ; Perú ; seed dispersal ; symbiosis ; tropical forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In ant gardens of lowland Amazonia, parabiotic ant speciesCamponotus femoratus andCrematogaster cf.limata parabiotica cultivate a taxonomically diverse group of epiphytic plants, whose establishment is restricted to arboreal carton ant nests. Epiphyte seeds are collected by workers ofCa. femoratus, the larger of the two ants, and stored unharmed in brood chambers where they subsequently germinate. Although seeds of some ant-garden epiphytes bear nutritional rewards, previous studies have shown that these rewards are not sufficient to explain the pattern of ant attraction to seeds. Five aromatic compounds occur frequently in and on the seeds of most ant-garden epiphytes and may be chemical cues by which ants recognize propagules of their symbiotic plants. The most widely distributed of these is methyl 6-methylsalicylate [6-MMS]1, previously reported as a major mandibular gland product in relatedCamponotus species and present in trace quantities inCa. femoratus males. (−)-Citronellol6 (previously unreported inCamponotus) was the principal volatile constituent in extracts of male heads, and (−)-mellein7 was present in small quantities. Discovery of 6-MMS inside the mandibular glands of maleCa. femoratus (and its presence in analogous glands of related ants) offers preliminary support for Ule's (1906) hypothesis that seeds attract ants by mimicking ant brood. In addition, the likely fungistatic activity of seed compounds suggests that they could retard microbial pathogens of ants and plants in the organic detritus of nest gardens. While the presence of identical seed compounds in so many unrelated plant lineages might represent a remarkable case of convergent evolution, other interpretations are possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01020495
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