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11.
Metallothionein purified from two genera of domesticated duck, Anas platyrhnchos and Cairina muschata, and their hybrid were analyzed and shown to consist of one identical amino acid sequence. Since most vertebrates carry two or more isospecies of this inducible, thiol rich, metal sequestering protein, this finding suggests that duck metallothionein is evolutionary primitive. 相似文献
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Kateryna Raykova Melina V. Jones Hwa Huang Paul F. Hoffman Michael Levy 《Journal of visualized experiments : JoVE》2015,(99)
The rat optic nerve is a useful model for stem cell regeneration research. Direct injection into the rat optic nerve allows delivery into the central nervous system in a minimally-invasive surgery without bone removal. This technique describes an approach to visualization and direct injection of the optic nerve following minor fascial dissection from the orbital ridge, using a conjunctival traction suture to gently pull the eye down and out. Representative examples of an injected optic nerve show successful injection of dyed beads. 相似文献
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Guo Hongwei Huang Tianqiu Zhao Jun Chen Hongwen Chen Guo 《Applied microbiology and biotechnology》2018,102(11):4653-4662
Applied Microbiology and Biotechnology - Short-chain carboxylic acids and their derivatives are widely utilized in all aspects of our daily life. Given their specific functional groups, these... 相似文献
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Xiang Liu Zhenghong Wang Chenyu Huang Manru Li Farkhanda Bibi Shurong Zhou Akihiro Nakamura 《Ecological Entomology》2020,45(3):547-554
1. Predator–prey interactions, especially those involving herbivorous insects, are of great importance in maintaining biodiversity. Predation pressure varies temporally in response to prey availability and activity. However, little is known about the patterns and drivers of fluctuations in predation pressure at fine temporal scales. 2. Artificial caterpillars (placed on plant leaves at breast height) were used to assess changes in predation pressure across four time intervals of the day in a monsoonal tropical rainforest in south-west China. The study examined how assemblage composition of arboreal ants, the dominant predators, changed across the same time intervals. The potential linkages between biotic (arboreal ants) and abiotic (temperature and light intensity) factors with predation rate were evaluated. 3. Predation rate on caterpillars during the early part of the night (19.00–01.00 hours) was significantly higher than in the morning, afternoon, or late night. Ant assemblage composition, rather than species richness or total abundance, best explained the variations in predation rate on artificial caterpillars. 4. The results help to strengthen understanding of trophic interactions by demonstrating that predation pressure fluctuates at finer timescales than previously tested, and that a particular set of ant species may play major roles in predation on caterpillars and possibly other organisms. 相似文献
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<正>Even after allogeneic hematopoietic stem cell transplantation(HSCT), which has been acknowledged as a curative procedure, relapse of leukemia remains the leading cause of death following transplantation and is a disappointment to transplant physicians. Leukemic relapse occurs due to leukemia cell escape from immune-mediated killing (immune escape) by pre-transplantation conditioning and post-transplantation immune control. Immune exhaustion of donor T 相似文献
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Pigeon metallothionein consists of two species 总被引:1,自引:0,他引:1
Two isospecies of metallothionein, a cysteine-rich protein that binds metals, exist in all mammals examined, but only one in some invertebrates and lower animals. Lower vertebrates such as fish and birds have one or two metallothionein genes depending upon the organism. In this study, we show by amino acid sequence determinations that two isospecies of metallothionein, 75% homologous to each other, can be induced by zinc to accumulate in pigeon livers. This is in contrast to single isospecies found in chicken and duck. Each of these two sequences consists of 63 amino acids, with all 20 cysteines in positions held invariant in most if not all class I mammalian metallothioneins. One of these two pigeon isometallothioneins is terminated with histidine at the carboxyl end, which is apparently unique to avians. Its sequence differs from that of duck and chicken by only four substitutions and is the predominant isospecies that accumulates upon induction. The other pigeon metallothionein has lysine at its carboxyl terminus and is devoid of arginine. None of these isospecies carries any aromatic amino acid, which is also characteristic of all higher metallothioneins. As this is the first demonstration with sequence data that two isospecies of metallothionein indeed exist in birds, these results suggest that pigeon metallothionein genes evolved from an ancestral form through duplication and mutation upon specification. 相似文献