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The behaviour of blue jays (Cyanocitta cristata) hunting for dispersed, cryptic prey was investigated in an operant simulation in which jays were trained to search projected images for noctuid moths. Each image contained either a single moth or no moth. Each trial was structured so as to simulate travelling between patches, searching within patches, and attacking and handling each moth that was detected. In two experiments in which the travel time between patches was manipulated, increases in travel time produced increased persistence within patches. Although this qualitative effect was predicted by the marginal value theorem, quantitative analyses revealed that the blue jays were using a strategy that was more sophisticated and more efficient than the simple time-in-patch rule implied by the marginal value theorem. 相似文献
74.
An evaluation of species relationships in the Porphyra perforata complex (Bangiales,Rhodophyta) using starch gel electrophoresis 总被引:1,自引:1,他引:0
Traditional morphological features have formed the basis for distinguishing species of Porphyra. Among these features are number of cell layers, number of chloroplasts per cell, arrangement of reproductive structures on the thallus, and overall morphology. Chromosome number and chromosome morphology have helped corroborate some species identities. A survey of northeast Pacific species of Porphyra using starch gel electrophoresis of 15 soluble proteins has shown that electrophoretic banding patterns provide a reliable diagnostic tool for species identification. Data from starch gel electrophoresis are presented to confirm the identities of species formerly associated with the Porphyra perforata species-complex in British Columbia and northern Washington. Porphyra abbottae, P. fallax, P. kanakaensis, and P. torta are recognized as distinct species, and Porphyra sanjuanensis is synonymized with P. perforata. 相似文献
75.
Dr. Premkumar Christadoss Jon M. Lindstrom Roger W. Melvold Norman Talal 《Immunogenetics》1985,21(1):33-38
Immune response (Ir) gene(s) at the I-A subregion of the mouse H-2 complex influence susceptibility to experimental autoimmune myasthenia gravis (EAMG). To determine the importance of the Ir gene product, the Ia antigens, in EAMG pathogenesis, we studied the degree of EAMG susceptibility of an I-A mutant strain, the B6.C-H-2
bm12 (bm12), and its parent B6/Kh. According to the cellular, humoral, biochemical, and clinical manifestations of EAMG, the I-A mutation converted an EAMG susceptible strain (B6/Kh) into a relatively resistant strain (bm12). The relative resistance to EAMG induction in bm12 may be due to the lack of Ia.8 and/or la.39 determinants and/or quantitative expression of la antigens.Abbreviations used in this paper MG
myasthenia gravis
- AChR
acetylcholine receptors
- EAMG
experimental autoimmune myasthenia gravis
- Ir
immune response
- B6
C57BL/6J
-
bm12
B6.C-H-2
bm12
- CFA
complete Freund's adjuvant
- LNC
lymph node cells
- PPD
purified protein derivative 相似文献
76.
Microbial populations and hydrocarbon biodegradation potentials in fertilized shoreline sediments affected by the T/V Exxon Valdez oil spill. 总被引:3,自引:1,他引:2
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J E Lindstrom R C Prince J C Clark M J Grossman T R Yeager J F Braddock E J Brown 《Applied microbiology》1991,57(9):2514-2522
The effort of clean up the T/V Exxon Valdez oil spill in Prince William Sound, Alaska, included the use of fertilizers to accelerate natural microbial degradation of stranded oil. A program to monitor various environmental parameters associated with this technique took place during the summer of 1990. Microbiological assays for numbers of heterotrophic and oil-degrading microbes and their hydrocarbon mineralization potentials were performed in support of this program. Fertilizer addition resulted in higher hexadecane and phenanthrene mineralization potentials on treated plots than on untreated reference plots. Microbial numbers in treated and reference surface sediments were not significantly different immediately after the first nutrient application in May 1990. However, subsurface sediments from treated plots had higher numbers of hydrocarbon degraders than did reference sediments shortly after treatment. The second application of fertilizer, later in summer, resulted in surface and subsurface increases in numbers of hydrocarbon degraders with respect to reference sediments at two of the three study sites. Elevated mineralization potentials, coupled with increased numbers of hydrocarbon degraders, indicated that natural hydrocarbon biodegradation was enhanced. However, these microbiological measurements alone are not sufficient to determine in situ rates of crude oil biodegradation. 相似文献
77.
Concurrent synthesis of overlapping octameric peptides corresponding to the sequence of the Torpedo acetylcholine receptor (AChR) alpha subunit has been carried out on polypropylene supports functionalized with primary amino groups according to a method developed by M. Geysen [(1987) J. Immunol. Methods 102, 259-274]. The peptides on the solid supports have been used in an enzyme-linked immunosorbent assay. Interactions of the synthetic peptides with antibodies are then detected without removing them from the solid support. By this procedure, epitopes of both antisera and monoclonal antibodies to the Torpedo acetylcholine receptor, its subunits, and synthetic peptide fragments have been mapped. Both rat and rabbit antisera to the alpha subunit show major epitopes spanning the residues 150-165, 338-345, and 355-366 on the Torpedo AChR alpha subunit. Epitopes of monoclonal antibodies to these major epitopes and to others have been rather precisely mapped by using this technique with peptides of varying lengths. The specificity of several of these mAbs are of interest because they have been used in mapping the transmembrane orientation of the AChR alpha-subunit polypeptide chain. 相似文献
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79.
Ana Maria Martins Kristin Lindstrom Sandra Obikawa Kyosen Maria Veronica Munoz-Rojas Nathan Thibault Lynda E. Polgreen 《BMC endocrine disorders》2018,18(1):83
Background
Mucopolysaccharidosis type I (MPS I) results in significant disease burden and early treatment is important for optimal outcomes. Recognition of short stature and growth failure as symptoms of MPS I among pediatric endocrinologists may lead to earlier diagnosis and treatment.Case presentation
A male patient first began experiencing hip pain at 5 years of age and was referred to an endocrinologist for short stature at age 7. Clinical history included recurrent respiratory infections, sleep apnea, moderate joint contractures, mild facial dysmorphic features, scoliosis, and umbilical hernia. Height was more than ??2 SD below the median at all time points. Growth velocity was below the 3rd percentile. Treatment for short stature included leuprolide acetate and recombinant human growth hormone. The patient was diagnosed with MPS I and began enzyme replacement therapy with laronidase at age 18.Conclusions
The case study patient had many symptoms of MPS I yet remained undiagnosed for 11 years after presenting with short stature. The appropriate path to MPS I diagnosis when patients present with short stature and/or growth failure plus one or more of the common signs of attenuated disease is described. Improved awareness regarding association of short stature and growth failure with attenuated MPS I is needed since early identification and treatment significantly decreases disease burden.80.