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1.
It has long been assumed that serial homologues are ancestrally similar—polysomerism resulting from a “duplication” or “repetition” of forms—and then often diverge—anisomerism, for example, as they become adapted to perform different tasks as is the case with the forelimb and hind limbs of humans. However, such an assumption, with crucial implications for comparative, evolutionary, and developmental biology, and for evolutionary developmental biology, has in general not really been tested by a broad analysis of the available empirical data. Perhaps not surprisingly, more recent anatomical comparisons, as well as molecular knowledge of how, for example, serial appendicular structures are patterned along with different anteroposterior regions of the body axis of bilateral animals, and how “homologous” patterning domains do not necessarily mark “homologous” morphological domains, are putting in question this paradigm. In fact, apart from showing that many so-called “serial homologues” might not be similar at all, recent works have shown that in at least some cases some “serial” structures are indeed more similar to each other in derived taxa than in phylogenetically more ancestral ones, as pointed out by authors such as Owen. In this article, we are taking a step back to question whether such assumptions are actually correct at all, in the first place. In particular, we review other cases of so-called “serial homologues” such as insect wings, arthropod walking appendages, Dipteran thoracic bristles, and the vertebrae, ribs, teeth, myomeres, feathers, and hairs of chordate animals. We show that: (a) there are almost never cases of true ancestral similarity; (b) in evolution, such structures—for example, vertebra—and/or their subparts—for example, “transverse processes”—many times display trends toward less similarity while in many others display trends toward more similarity, that is, one cannot say that there is a clear, overall trend to anisomerism. 相似文献
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Between June 1986 and October 1992, in 3 periods totaling 12 months, we studied social organization of pigtailed langurs (Simias concolor)in the Pagai Islands, Indonesia. With one possible exception, all of 20 family groups contained only 1 adult male each. Nine
of them contained only 1 adult female,and 11 contained ≥2 adult females. Mean group size is 4.1 individuals. Home ranges varied from 7 to 20 ha, and population
density averages 21 animals/km
2
. Simias concoloris sexually dimorphic⤖n a museum sample males average 29% heavier than females, and their canine teeth are on average nearly
twice the length of female canines. Combined data from several studies indicate that 60% of S. concolorgroups contain an adult pair plus young,and 40% are multifemale groupings. We sggest that any 1-male mating system that comprises a mixture of 1-female and multifemale
groups in the same population should be termed monandry. 相似文献
6.
Serine protein kinase activity associated with rotavirus phosphoprotein NSP5. 总被引:5,自引:4,他引:1 下载免费PDF全文
The rotavirus nonstructural protein NSP5, a product of the smallest genomic RNA segment, is a phosphoprotein containing O-linked N-acetylglucosamine. We investigated the phosphorylation of NSP5 in monkey MA104 cells infected with simian rotavirus SA11. Immunoprecipitated NSP5 was analyzed with respect to phosphorylation and protein kinase activity. After metabolic labeling of NSP5 with 32Pi, only serine residues were phosphorylated. Separation of tryptic peptides revealed four to six strongly labeled products and several weakly labeled products. Phosphorylation at multiple sites was also shown by two-dimensional polyacrylamide gel electrophoresis (PAGE), where several isoforms of NSP5 with different pIs were identified. Analysis by PAGE of protein reacting with an NSP5-specific antiserum showed major forms at 26 to 28 and 35 kDa. Moreover, there were polypeptides migrating between 28 and 35 kDa. Treatment of the immunoprecipitated material with protein phosphatase 2A shifted the mobilities of the 28- to 35-kDa polypeptides to the 26-kDa position, suggesting that the slower electrophoretic mobility was caused by phosphorylation. Radioactive labeling showed that the 26-kDa form contained additional phosphate groups that were not removed by protein phosphatase 2A. The immunoprecipitated NSP5 possessed protein kinase activity. Incubation with [gamma-32P]ATP resulted in 32P labeling of 28- to 35-kDa NSP5. The distribution of 32P radioactivity between the components of the complex was similar to the phosphorylation in vivo. Assays of the protein kinase activity of a glutathione S-transferase-NSP5 fusion polypeptide expressed in Escherichia coli demonstrated autophosphorylation, suggesting that NSP5 was the active component in the material isolated from infected cells. 相似文献
7.
J Fuentes Mota J Fernández-Bola?os Guzmán J M García Fernández W Moreda C Ortiz M A Pradera I Robina C Welsh 《Carbohydrate research》1992,232(1):47-57
The preparation of 2,3,4-tri-O-benzyl- (3), 2,3,4-tri-O-acetyl- (4), and 2,3,4-tri-O-benzoyl-N-(2,2-diethoxycarbonylvinyl)-6-O-trityl-beta- D-glucopyranosylamine (5) is described. The reaction of 3-5 with 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide yields 2,3,4-tri-O-benzyl- (9), 2,3,4-tri-O-acetyl- (10), and 2,3,4-tri-O-benzoyl-N-(2,2-diethoxycarbonylvinyl)-6-O-(2,3,4,6-tet ra-O- acetyl-beta-D-glucopyranosyl)-beta-D-glucopyranosylamine (11), respectively. 2,3,4-Tri-O-benzyl- (6), 2,3,4-tri-O-acetyl- (7), and 2,3,4-tri-O- benzoyl-N-(2,2-diethoxycarbonylvinyl)-beta-D-glucopyranosylamine (8) are also described. 相似文献
8.
M A Moya M E Fuentes N C Inestrosa 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1991,98(2-3):299-305
1. Xenopus laevis oocytes express endogenously two components of the cholinergic system: the muscarinic receptors and the acetylcholinesterase (AChE). 2. A biochemical characterization of this enzyme was carried out. 3. The results established that the activity found in the oocytes correspond to 'true' AChE with a molecular weight of 65,000 Da and a sedimentation coefficient of 3-4 S. 4. The enzyme aggregates in the absence of detergent suggesting that it possess an hydrophobic character; despite that, it is not sensitive to PIPLC. 5. A comparison with the Xenopus brain and muscle AChE shows different post-translational modifications and catalytic properties with the oocyte AChE. 相似文献
9.
A naloxone-reversible enhancement of systolic blood pressure (BP) was induced in rats by application of three different types of stressor, i.e. intense light and sound, cold and foot-shock. In the case of labile high BP provoked by short-term isolation, the opiate antagonist naloxone (1 mg/Kg, i.p.) was also found to reverse hypertension. Naltrexone (2.5 mg/Kg, i.p.) also diminished high BP readings of briefly isolated rats. Conversely, blockade of the opiate receptor with naloxone did not alter elevated BP in cases of established hypertension (spontaneously hypertensive rats, deoxycorticosterone (DOCA)-salt rats and long-term isolated rats). These data can be taken as an evidence of opioid involvement at the onset of high BP readings induced by stress. However, once hypertension becomes established, the opioid system appears to recover its silent features. 相似文献
10.
Carlos?Talavera Fernando?Contreras Francisco?Espadas Gabriela?Fuentes J.?M.?SantamaríaEmail author 《Plant Cell, Tissue and Organ Culture》2005,83(3):287-292
Plantlets of coconut were cultured in vitro under three different ambient conditions including a standard culture room, a culture room inside a glasshouse with natural light but controlled temperature, and a standard glasshouse with natural light and natural fluctuations of temperature. Plantlets from the 3 treatments were compared in terms of growth, plant survival as well as net photosynthesis and efficiency of PSII (Fv/Fm ratio) both at the end of the in vitro stage and at 3 stages of ex vitro acclimatization. At the end of the in vitro stage, plantlets cultured in vitro under glasshouse conditions showed the best performance showing the highest photosynthesis rate, dry weight and number of leaves. Plantlets from the standard culture room showed the lowest photosynthesis and growth rate. After 6 months of ex vitro acclimatization, plantlets originally grown in vitro under glasshouse conditions maintained better field survival and growth rates in terms of fresh weight, dry weight and leaf number than plantlets originally grown in vitro in the standard culture room. Although more studies are required to define the reason for this effect, it is clear that the conditions of standard culture rooms are not the best for in vitro cultivation of coconut and perhaps other tropical species. 相似文献