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1.
C. ALLAN CHILD 《Zoological Journal of the Linnean Society》1978,63(1-2):133-144
A large sample of the pycriogonid Anoplodactylus portus , collected from the Pacific side of the Panama Canal Zone, contains a high percentage of gynandromorphs. The literature on aquatic arthropod gynandromorphs is outlined. The nature and variations of the sexual mosaic population are described and discussed. The several morphological differences between normal and mosaic members of the population are illustrated, and the possible origin of these gynandromorphs is discussed. 相似文献
2.
Incipient forebrain boundaries traced by differential gene expression and fate mapping in the chick neural plate 总被引:1,自引:0,他引:1
We correlated available fate maps for the avian neural plate at stages HH4 and HH8 with the progress of local molecular specification, aiming to determine when the molecular specification maps of the primary longitudinal and transversal domains of the anterior forebrain agree with the fate mapped data. To this end, we examined selected gene expression patterns as they normally evolved in whole mounts and sections between HH4 and HH8 (or HH10/11 in some cases), performed novel fate-mapping experiments within the anterior forebrain at HH4 and examined the results at HH8, and correlated grafts with expression of selected gene markers. The data provided new details to the HH4 fate map, and disclosed some genes (e.g., Six3 and Ganf) whose expression domains initially are very extensive and subsequently retract rostralwards. Apart from anteroposterior dynamics, some genes soon became downregulated at the prospective forebrain floor plate, or allowed to identify an early roof plate domain (dorsoventral pattern). Peculiarities of the telencephalon (initial specification and differentiation of pallium versus subpallium) are contemplated. The basic anterior forebrain subdivisions seem to acquire correlated specification and fate mapping patterns around stage HH8. 相似文献
3.
目的:总结基于鼻翼软骨三脚架结构的改建技术在鼻尖综合整形术中的应用经验。方法:从2012年09月到2015年02月间,共84例求美者在我院进行初次鼻尖综合整形术。3例为男性,81例为女性。年龄20-45岁,平均年龄31.7岁。其中鼻头肥大伴鼻背低平65例,行鼻翼软骨缝合+鼻翼软骨切除+鼻假体+自体软骨帽状移植术;鼻头肥大、鼻背低平伴鼻小柱短小19例,行自体软骨鼻小柱支撑+鼻翼软骨切除+鼻翼软骨缝合+鼻假体植入+自体软骨帽状移植术。结果:84例求美者术后随访1个月-2年,除1例病例鼻头过于肥大,鼻尖形态改善不明显以外,其余求美者鼻额角及鼻尖角度及均较术前有明显改善,鼻小柱短小组的鼻小柱长度也较术前有明显改善。所有病例切口瘢痕均不明显,无明显并发症出现。结论:针对不同鼻翼软骨发育条件下的病人,个性化的应用鼻翼软骨三脚架结构改建的鼻尖综合整形术具有较好的临床效果,须根据不同病人特点选用。 相似文献
4.
A survey of androconial organs in the Riodinidae (Lepidoptera) 总被引:1,自引:0,他引:1
A comprehensive survey of the occurrence and morphology of alar, abdominal and appendage androconial organs in the Riodinidae is presented based on light microscopy and scanning electron microscopy. Although historically poorly studied, the group actually possesses among the greatest diversity of androconial organs in the butterflies, including coremata, reported here for the first time outside the Lycaenidae and Nymphalidae, and hindleg hairpencils, reported here for the first time in the true butterflies. Twenty-five percent of riodinid species are reported to have androconial organs. The mode of function of these organs and their role in courtship is discussed where known, based on field observations. A number of taxonomic changes are made at the tribal, generic and species level, predominantly in the Symmachiini, based on the occurrence and structure of androconia. © 2002 The Linnean Society of London, Zoological Journal of the Linnean Society , 2002, 136 , 171–197. 相似文献
5.
Conditional cell ablation via diphtheria toxin reveals distinct requirements for the basal plate in the regional identity of diencephalic subpopulations
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Bumwhee Lee Duc Tri Lam Kwanghee Baek Jaeseung Yoon Yongsu Jeong 《Genesis (New York, N.Y. : 2000)》2015,53(6):356-365
The mammalian diencephalon is the caudal derivative of the embryonic forebrain. Early events in diencephalic regionalization include its subdivision along the dorsoventral and anteroposterior axes. The prosomeric model by Puelles and Rubenstein (1993) suggests that the alar plate of the posterior diencephalon is partitioned into three different prosomeres (designated p1–p3), which develop into the pretectum, thalamus, and prethalamus, respectively. Here, we report the developmental consequences of genetic ablation of cell populations from the diencephalic basal plate. The strategy for conditionally regulated cell ablation is based on the targeted expression of the diphtheria toxin gene (DTA) to the diencephalic basal plate via tamoxifen‐ induced, Cre‐mediated recombination of the ROSADTA allele. We show that activation of DTA leads to specific cell loss in the basal plate of the posterior diencephalon, and disrupted early regionalization of distinct alar territories. In the basal plate‐deficient embryos, the p1 alar plate exhibited reduced expression of subtype‐specific markers in the pretectum, whereas p2 alar plate failed to further subdivide into two discrete thalamic subpopulations. We also show that these defects lead to abnormal nuclear organization at later developmental stages. Our data have implications for increased understanding of the interactive roles between discrete diencephalic compartments. genesis 53:356–365, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
6.
目的:探讨鼻唇沟扩张瘢痕皮瓣或瘢痕皮瓣修复烧伤后鼻翼缺损的临床疗效。方法:回顾性分析我院于2006年6月至2012年6月收治的烧伤后鼻翼缺损患者18例。男性10例,女性8例,年龄6~64岁,平均35.3岁。其中面部深Ⅱ度烧伤12例,Ⅲ度烧伤6例;病程8个月~7年。应用鼻唇沟扩张瘢痕皮瓣修复11例,鼻唇沟瘢痕皮瓣修复7例。缺损面积最大者为1.8×2.5 cm2,最小者为0.7×1.3 cm2。结果:术后皮瓣全部成活,无并发症发生。18例鼻翼缺损患者外观均明显改善,皮瓣外形不臃肿,颜色、质地与周围皮肤相近。术后鼻部瘢痕不明显,供区鼻唇沟无明显瘢痕增生。结论:保留残存鼻翼的解剖结构,利用鼻唇沟扩张瘢痕皮瓣或瘢痕皮瓣重建鼻侧背部结构,是鼻翼缺损修复的良好方法。 相似文献
7.
Kelley J 《Journal of human evolution》2008,54(4):530-537
The sample of the less common hominoid species at Pa?alar, Kenyapithecus kizili, is characterized by a number of unusual attributes. All ten of the upper central incisors attributed to this species show a distinct, identical pattern of two linear enamel hypoplasias. The two hypoplasias occur on the same portion of the labial crown face, revealing that the two hypoplasia-causing events occurred at the same stage of development in all individuals. The morphology of the two hypoplasias and the amount of time between them, as determined by both their separation and counts of perikymata, are also the same on all teeth. In addition, all of the approximately 70 teeth assigned to K. kizili appear to come from young adults based on degrees of wear; there are no younger or older individuals (diagnostic morphology at most tooth positions would be evident even with heavy wear). Thus, all of the K. kizili individuals (minimum number of individuals is nine: seven males, two females) appear to have died at essentially the same age. It is concluded that the most plausible interpretation of all these features is that the incisor hypoplasias were caused by the same two events in all the K. kizili individuals and that these individuals therefore represent a single birth cohort. As such, and because they died at essentially the same age, they would also have died at the same time, which is consistent with the catastrophic nature of the Pa?alar deposits. The number of coincidences needed to explain all of the attributes of the K. kizili sample if these animals were born in, and died in, different years seems highly improbable. Moreover, the lack of a typical age-class structure for the K. kizili sample, or any age-class structure at all beyond the one age class of young adult, strongly suggests that the species was not resident in the area that contributed to the Pa?alar accumulation, and that K. kizili was not permanently sympatric with the other Pa?alar hominoid, Griphopithecus alpani. Rather, the nine K. kizili individuals must have been transients in, or recent immigrants to, the area at the time of the events that led to the formation of the site. Recent observations on social associations in male chimpanzees offer at least a possible interpretive framework to explain this unprecedented occurrence in the primate fossil record. 相似文献
8.
The importance of leaf area of in vitro propagated potato (Solanum tuberosum L.) plantlets for further growth during acclimatisation and the after-effects of in vitro treatments on growth were examined. The in vitro treatments included different levels of alar, nitrogen or mannitol or different temperatures during the last in vitro phase, the rooting phase. Leaf area or ground cover was recorded one day after planting to soil and at the end of the first
phase of ex vitro growth, the acclimatisation phase. Regression analysis showed that leaf area of a transplant at the end of acclimatisation
phase was positively influenced by leaf area of the same plantlet at the beginning of the phase. The relative increase in
leaf area during acclimatisation (increase/early leaf area) was linearly related to the inverse of the early leaf area, indicating
almost comparable relative increases for plantlets having larger early leaf areas, but more variable responses for plantlets
having smaller early leaf areas. In vitro treatments mainly affected leaf area of transplants through their effects on early leaf area. Adding alar, reducing nitrogen
and reducing temperature increased leaf area. Reducing mannitol increased ground cover. A lower nitrogen concentration and
higher temperature in some cultivars had slight negative effects on the relative increase in leaf area after acclimatisation.
For nitrogen these negative effects were less significant than the positive effects through early leaf area. Results stress
the importance of manipulation of leaf area in vitro to enhance plant performance in later stages of growth.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
At harvest, fruit from apple trees sprayed with daminozide (+daminozide) had lower levels of aminocyclopropane-1-carboxylic acid (ACC) and produced significantly lower amounts of ethylene than untreated (–daminozide) fruit. Flesh discs from the fruit of +daminozide and –daminozide trees were fed precursors of ethylene to determine how daminozide inhibits ethylene production. ACC was metabolized to ethylene regardless of treatment. Methionine (MET), however, was only converted to ethylene by –daminozide fruit, and only after the fruit had been maintained at 4 °C for 5 months. +Daminozide fruit failed to convert MET to ethylene at harvest, as well as after cold storage. When daminozide was added to the incubation media of flesh discs it did not inhibit ethylene production or the conversion of ACC to ethylene. The addition of daminozide did, however, inhibit the metabolism of exogenous MET to ethylene. Aminooxyacetate acid (AOA) blocked both the endogenous production of ethylene and that from MET feeds. Daminozide inhibits ethylene production by preventing the conversion of MET to ACC, but it does not appear to act as a simple competitive inhibitor of ACC synthase activity.Abbreviations ACC
aminocyclopropane-1-carboxylic acid
- AVG
aminoethoxyvinylglycine
- AOA
aminooxyacetic acid
- CH
cycloheximide
- MET
methionine
- PUT
putrescine
Author for correspondence 相似文献
10.
Neuronal migration is required for the establishment of specific neural structures, such as layers and nuclei. Neurons migrate along specific migratory routes toward their final destinations, sometimes across long distances. However, the cellular and molecular interactions that control neuronal migration are largely unknown. Here, we examined the mechanism underlying the transmedian migration of precerebellar neurons using a flat whole-mount preparation of the rat embryo. These neurons were initially attracted by the floor plate (FP) at the ventral midline. However, after crossing the midline, they lost their responsiveness to the FP and became attracted by the alar plate (AP). Although the loss of responsiveness to FP cues was caused by an encounter of migrating cells with the FP, the gain of responsiveness to AP cues occurred irrespective of their encounter with the FP. These results identify a crucial change in the response of migrating cells to attractive guidance cues during the transmedian migration of precerebellar neurons. 相似文献