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921.
922.
I. Barber S. A. Arnott V. A. Braithwaite J. Andrew W. Mullen F. A. Huntingford 《Journal of fish biology》2000,57(3):777-790
The extent, corrected for body size, and intensity of nuptial coloration of breeding male three-spined sticklebacks Gasterosteus aculeatus L. from a Scottish freshwater population were highly variable but correlated, both in the field and after a period of nest-building in the laboratory. However, marked changes in coloration occurred between the field and the laboratory screenings and the coefficients of variation amongst males decreased. In general, intensity of coloration increased between the field and laboratory screenings, but changes in size-corrected extent were not consistently directional. For both indices, there was a negative relationship between the field value and amount by which colour changed between sampling sessions, with fish that were initially the dullest gaining most in colour. Size-corrected extent and (in particular) intensity of coloration in the field sample were associated positively with body condition measured post mortem and there was a negative, though non-significant, relationship between the extent of coloration and the proportion of white cells in the blood. No such associations were found for the laboratory colour screening. The concentration of astaxanthin in the lower jaw was related strongly and positively to both size-corrected extent and intensity of coloration at the laboratory screening and related negatively, though non-significantly, to proportional white cell counts. These data have implications both for the interpretation of previous laboratory studies and for the design of future experiments, and suggest that coloration is only a true indicator of male quality when measured in the field. 相似文献
923.
924.
Double immunodiffusion in agar gel with antiserum to carp transferrin was used to prove immunological relatedness between the transferrins of some European cyprinid fish. Quantitative differences between transferrins of nine species of cyprinid fish were studied by micro-complement fixation with the use of entisera to transferrins of four species. Immunological distances were conspicuously great and amounted on average to about 125 immunological distance units (IDU). A high rate of evolution of transferrins wes obtained. namely 4.2 IDU/million years, which represents about 0.84% sequence differences per million years. 相似文献
925.
926.
Structural and functional studies on different human FABP types 总被引:6,自引:0,他引:6
Veerkamp J.H. van Moerkerk H.T.B. Prinsen C.F.M. van Kuppevelt T.H. 《Molecular and cellular biochemistry》1999,192(1-2):137-142
Interaction of various ligands with recombinant proteins of 5 human FABP types was studied by radiochemical and fluorescence procedures. Liver, heart, intestinal and myelin FABP showed a higher affinity for oleic acid than adipocyte FABP. Intestinal and adipocyte FABP had a relatively high Kd value for arachidonic acid. Liver and intestinal FABP showed high affinity for DAUDA in contrast to the other FABP types. ANS was only well bound by liver and adipocyte FABP. Retinol was not bound by any FABP type, retinoic acid only by adipocyte FABP. Data indicate the importance of both electrostatic and hydrophobic interaction for the ligand-FABP binding. The immunological crossreactivity between six human FABP types including epidermal FABP and their respective antibodies raised in rabbit, chicken and mouse appeared to be low and may suggest heterogeneity of protein surface. 相似文献
927.
Young W. Kwon Susan J. Abbondanzo Colin L. Stewart Mark E. Gurney 《Developmental neurobiology》1995,28(1):35-50
We show that leukemia inhibitory factor (LIF) plays a physiological role in the programmed withdrawal of synapses form neonatal muscles. First, LIF mRNA is present in embryonic skeletal muscle and is developmentally regulated. We detect high levels of LIF mRNA at embryonic day 17 (E17) in mouse hind leg muscles. The content of LIF mRNA falls 10-fold between E17 and birth and then remains low in the neonate and adult. The decrease in LIF mRNA in skeletal muscle coincides with the end of secondary myogenesis and the completion of the adult number of myofibers. Second, treatment of the mouse tensor fascia latae (TFL), a superficial muscle of the hind leg, with LIF from birth (100 ng/day), transiently delays the withdrawal of excess inputs from polyneuronally innervated myofibers by approximately 3 days. The midpoint of the process is shifted from 7.5 ± 0.5 to 10.2 ± 0.6 days of age. LIF treatment delays synapse withdrawal by altering its timing without an appreciable effect on its rate. Third, in mice homozygous for a distruption of the LIF gene, the midpoint in the reduction of multiply innervated TFL myofibers occurs 1 day earlier, at 6.5 ± 0.5 days of age. Muscle fiber number is unchanged in LIF null mice. Treatment with LIF does not alter the rate of neonatal growth, the number of muscle fibers in the TFL, or the reappearance of inputs that have been eliminated. Instead, LIF appears to delay maturation of the motor unit by transiently delaying the onset of synapse withdrawal. We hypothesize that this is a necessary component of a selective process that will operate simultaneously and equally on multiple, competing motor units. © 1995 John Wiley & Sons, Inc. 相似文献
928.
Dr. Yuri V. Panchin Pavel V. Zelenin Lyudmila B. Popova 《Invertebrate neuroscience : IN》1997,3(1):27-40
The neural network underlying rhythmic wing movements in the molluscClione limacina is well-studied. Two different groups of motoneurons innervate two distinct groups of wing muscles. The locomotor rhythm
generated in the left and right pedal ganglia is synchronized by interneurons. When the axons of the locomotor motoneurons
are crushed, numerous fine neurites sprout towards the denervated muscles and reach them in 8–15 days. At this stage motoneurons
project to and synapse on not only correct but equally incorrect muscle targets. After 2 weeks of regeneration the number
of incorrect neurites and synaptic connections begins to decrease and following 1.5–2 months all incorrect connections are
eliminated, incorrect axons are withdrawn and the behavioral deficit is compensated. In this study the regeneration of interneurons
and the growth profiles of inter- and motoneurons were also studiedin vitro. Two individually isolated pedal ganglia were co-cultured in three different configurations: a) the wing nerve stump from
one ganglion was fixed against the commissural stump from another ganglion; b) the wing nerve stumps were fixed against each
other; c) the commissural stumps were fixed against each other. Under the above experimental conditions we found that the
interneurons were able to cross only the contact between two commissural stumps, and in this case found their original targets,
restored correct connections and synchronized the rhythm in two pedal ganglia. In contrast, motoneurons were able to cross
all types of contacts. 相似文献
929.
Mohammed Akaaboune Jianxin Ma Barry W. Festoff Barry D. Greenberg Daniel Hantaï 《Developmental neurobiology》1994,25(5):503-514
Kunitz-inhibitor containing forms of the β-amyloid precursor protein (βAPP), known also as protease nexin II (PNII), and α1-antichymotrypsin (α1-ACT), a serpin, are important components of the serine protease and inhibitor balance in many tissues. In the nervous system, this balance may have trophic or growth factor activity at different stages of development, after injury and in disease states. In the current study, using immunocytochemistry and Western blotting with antibodies against the human homologues, we analyzed whether denervation affected the localization of βAPP and α1-ACT in adult mouse muscle following axotomy. In mouse muscle, antitive band and anti-human βAPP antibody a band at 92 kD in both normal and denervated extracts. βAPP was present in normal mouse muscle at both neuromuscular junctions and within intramuscular nerves. α1-ACT was also detected at neuromuscular junctions, on the perineruim and endothelial cell surfaces. Following axotomy, both βAPP and α1-ACT disappeared from intramuscular nerves simultaneously. However, at the neuromuscular junction, α1-ACT decreased more rapidly with βAPP lingering before disappearing. Since both α1-ACT as well as βAPP are present within senile plaques in Alzheimer's disease brains such experiments with the nicotinic, cholinergic neuromuscular synapse in denervated muscle may help to focus experiments on the mechanism of synapse loss as well as plaque deposition in this disease. © 1994 John Wiley & Sons, Inc. 相似文献
930.
Polyclonal and monoclonal antibodies against rat liver nuclear lamins have been used to evaluate the immunological cross-reactivity of lamins with a given antibody in a variety of animal and plant cells. The results indicated that lamins of all vertebrate cells but not invertebrate cells share at least one antigenic determinant, resulting in immunological cross-reaction with polyclonal antisera to lamina from rat liver. The range of cross-reaction with monoclonal antibody to rat lamins includes all mammalian cells tested but we observed no reaction with other vertebrate and invertebrate cells. Thus, by means of immunological cross-reaction a less stringently conserved pattern is observed for lamins than, for example, cytoskeletal proteins. We have also investigated the fate of the nuclear lamins during meiosis in testes and ovaries of the mouse. Lamins are absent from male meiotic cells and during oogenesis in meiotic prophases. 相似文献