Ventrally emigrating neural tube cells migrate into the developing vestibulocochlear nerve and otic vesicle

Virtually all cell types in the inner ear develop from the cells of the otic vesicle. The otic vesicle is formed by the invagination of non-neural ectodermal cells known as the otic placode. We investigated whether a recently described cell population, originating from the ventral part of the hindbrain neural tube known as the ventrally emigrating neural tube (VENT) cells, also contributes cells to the otic vesicle. The ventral hindbrain neural tube cells were labeled with the fluorescent vital dye DiI or replication-deficient retroviruses containing the LacZ gene in chick embryos on embryonic day 2, after the emigration of neural crest from this region. One day later, the labeled cells were detected only in the hindbrain neural tube. Shortly thereafter, the labeled cells began to appear in the eighth (vestibulocochlear) cranial nerve and otic vesicle. From embryonic day 3.5-5, the labeled cells were detected in the major derivatives of the otic vesicle, i.e. the endolymphatic duct, semicircular canals, utricle, saccule, cochlea, and vestibulocochlear ganglion. That the emigrated cells originated from the ventral part of the hindbrain neural tube was confirmed by focal application of DiI impregnated filter paper and with quail chimeras. It is concluded that, in addition to the otic placode cells, the otic vesicle also contains the ventrally emigrating neural tube cells, and that both cell populations contribute to the structures and cell types in the inner ear. It is well known that inductive signals from the hindbrain are required for the morphogenesis of the inner ear. The migration of the hindbrain neural tube cells into the otic vesicle raises the possibility that the inductive effect of the hindbrain might be mediated, at least in part, by the ventrally emigrating neural tube cells and that, therefore, a mechanism exists that involves cells rather than diffusible molecules only.     

β,β′-Iminodipropionitrile toxicity in normal and congenitally neurofilament-deficient Japanese quails

Morphological effects of a neurotoxin, ,-iminodipropionitrile (IDPN) were analyzed in normal and cogenitally neurofilament (NF)-deficient Japanese quails. These quails (6 weeks old) were injected intraperitoneally with IDPN (0.2 g/kg body weight) three times every 3 days. They were necropsied at 10 to 12 days after the first injection. In normal quails, axonal swellings were observed histologically in the ventral motoneurons, ventral root, commissura grisea and spinal ganglion in the cervical and synsacral spinal cord. Electron microscopically, the changes consisted of increased NFs, with scattered mitochondria, smooth endoplasmic reticulum and microtubules. The myelin sheaths of the involved nerves were thinner than those of the normal axons. These lesions were similar to those induced by IDPN intoxication in mammalian experimental animals. In NF-deficient quails injected with IDPN, no axonal changes were detected. These findings suggested that IDPN selectively attacked the NFs.     

麦胚抗动脉粥样硬化实验研究

雄性鹌鹑高脂饲料喂养45d可形成典型的动脉粥样硬化病变。给予麦胚每只10g/d具有明显的抗动脉粥样硬化作用,表现体重增加,生理活动增强,降低血清胆固醇,显著增高HDL-C,其抗动脉粥样硬化作用优于烟酸肌醇酯(每日2.5mg/100g体重),且无药物所致进食减退、体重减轻、肝脏脂肪变性等副作用。实验表明麦胚是一种理想的有前途的抗动脉粥样硬化食品。     

Quail carry sialic acid receptors compatible with binding of avian and human influenza viruses

There is growing evidence that some terrestrial avian species may play a role in the genesis of influenza viruses with pandemic potential. In the present investigation, we examined whether quail, a widespread-farmed poultry, possess the proper characteristics for serving as an intermediate host for the zoonotic transmission of influenza viruses. Using a lectin-based staining based on specific agglutinins, we found that, in addition to the presence of sialic acid alpha2,3-galactose (SAalpha2,3-gal) linked receptors, there are abundant sialic acid alpha2,6-galactose (SAalpha2,6-gal) linked receptors in quail trachea and intestine. The presence of abundant SAalpha2,6-gal-linked receptors explains, at least in part, the circulation of avian influenza viruses with human-like receptor specificity in quail. In quail trachea, SAalpha2,3-gal linked receptors are present primarily in non-ciliated cells, while SAalpha2,6-gal linked receptors are localized predominantly on the surface of ciliated cells. In quail intestine, both types of receptors were found on epithelial cells as well as in crypts. In a solid-phase overlay binding assay, both avian and human influenza viruses bind to plasma membranes prepared from epithelial cells of quail trachea and intestine, strongly suggesting that these receptors are functional for binding of influenza viruses from different species. Together with previous observations, these results are consistent with the notion that quail could provide an environment for the spread of reassortants between avian and human influenza viruses, thus acting as a potential intermediate host.     

鹌鹑高血尿酸高甘油三酯血症模型塑造

目的和方法:建立一种与人类代谢途径相似的高血尿酸并高甘油三酯血症动物模型。鹌鹑随机分为3组, 除空白对照组外, 模型Ⅰ组以15g·kg^-1·d^-1的酵母食饵喂饲鹌鹑, Ⅱ组以10g·kg^-1·d^-1的酵母食饵喂饲鹌鹑, 动态检测血清尿酸(UA)、甘油三酯(TG)、胆固醇(TC)、尿素氮(BUN)、血糖(GLU)、黄嘌呤氧化酶(XOD)含量。结果:模型Ⅰ组7d后血尿酸水平开始升高, 第2、3、4、5周血UA水平显著高于空白对照组(P＜0.05, P＜0.05, P＜0.05, P＜0.01);第3周血TG水平显著高于空白对照组, 持续至5周, 血BUN含量与空白对照组比差异不显著;GLU及TC可见一过性升高。模型Ⅱ组动物血UA水平亦于第2周升高;TG于第4周显著高于空白对照组, 但持续时间短;血BUN于第2周和第3周显著高于空白组(P＜0.05)。结论:以15g/kg酵母喂饲鹌鹑, 可建立高血尿酸高甘油三酯模型, 以进行尿酸与血脂代谢交互紊乱的药理与病理研究。     

Developmental changes in progesterone biosynthesis and metabolism in the quail brain

We have recently demonstrated that the quail brain possesses the cholesterol side-chain cleavage enzyme (cytochrome P450scc) and 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4-isomerase (3beta-HSD) and produces pregnenolone, pregnenolone sulfate and progesterone from cholesterol. To elucidate the developmental changes in progesterone biosynthesis and its metabolism in the quail brain, we examined the expression and activity of 3beta-HSD and progesterone metabolite(s) during embryonic and post-hatched ages. Both the progesterone concentration and 3beta-HSD mRNA expression in the brain were almost constant during embryonic and post-hatched ages. The conversion of pregnenolone to progesterone (net 3beta-HSD enzymatic activity) was also constant during development and at maturity. However, without radioinert progesterone, the production of progesterone was drastically reduced in the embryonic brain, indicating active progesterone metabolism at the embryonic stage. Biochemical analysis together with HPLC and TLC revealed that only the embryonic brain actively produced 5beta-dihydroprogesterone from progesterone. Thus, progesterone production may be constant during embryonic and post-hatched development and in adulthood, whereas 5beta-dihydroprogesterone may be produced actively only in embryonic life due to 5beta-reductase.     

Renal carbonic anhydrase in the quail Coturnix coturnix japonica. II. Changes of enzyme activity in developing and regressing mesonephros

Summary Carbonic anhydrase activity was studied during development and regression of the quail mesonephros by in situ and extra situm investigation. A close correlation was noted between enzyme expression and tissue morphofunctional state. Carbonic anhydrase appears in early development; its highest activity is reached when the kidney is actively secreting, followed by a decrease concomitant with tissue involution. The main localization of the reaction product is the distal tubule showing strongly positive cells intercalated with clear, negative ones. In the functional organ, staining was found at the level of transitional and connecting segments and Wolffian duct. The comparison with the histochemical pattern of the quail metanephros suggests that the functional meaning of renal carbonic anhydrase might be the same both in transitory and in permanent kidney.     

碱提类肝素组分Ⅱ对鹌鹑血清及动脉壁胆固醇的影响

研究碱提类肝素组分Ⅱ(C_2)对鹌鹑血清及动脉壁胆固醇的影响,结果表明C_2能抑制高脂饮食所致的Tc的升高,降脂率约为35%,能提高HDL-c/Tc,HDL_2-c/HDL_3-c比值,约可减少30%的胆固醇及脂质在动脉壁的沉积。     

Animal lateralization and social recognition: quails use their left visual hemifield when approaching a companion and their right visual hemifield when approaching a stranger

Quails were tested for leftward and rightward turning preferences in a detour task. When facing a mirror located behind a barrier composed of vertical bars, quails showed a striking population-level preference for turning leftward. In order to check whether the asymmetry reflected a motor or a sensory (i.e. visual hemifield) bias, in a second experiment quails were reared in pairs and then tested in the detour task with a familiar (companion) or an unfamiliar (stranger) conspecific as a target. Quails turned leftward when viewing the stranger, but they turned rightward when viewing the companion. These findings are discussed in relation to current evidence for brain lateralization in response to social stimuli in non-human animals.     

Expression of Kin17 and 8-OxoG DNA glycosylase in cells of rodent and quail central nervous system

Kin17 and 8-Oxoguanine DNA glycosylase (Ogg1) are proteins, respectively, involved in illegitimate recombination and DNA repair in eukaryotic cells. To characterize the expression of these proteins in cell types of rodent and avian brains, we combined immunocytochemistry for either Kin17 or Ogg1 proteins with glial fibrillary acidic protein (GFAP, an astrocyte marker) immunodetection on the same tissue section. Both Kin17 and Ogg1 proteins were localized in cell nuclei and were extensively distributed in neuronal populations of quail and rodent brains. However, GFAP-immunoreactive cells were never labeled by Kin17 protein. This was observed in nerve fiber tracts, in the cerebral cortex, the hippocampal formation, the hypothalamic region, and the periventricular regions of the brain of both species studied. These results were confirmed by combining in situ hybridization of kin17 mRNA and GFAP immunodetection. On the contrary, GFAP-immunoreactive cells were often labeled by the Ogg1 protein in brain structures such as fiber tracts, the cortical surface, the cerebellum, and the ependymal surface of both quail and mouse brains. Our results suggest that the expression of the Kin17 protein (observed in neurons) and that of the Ogg1 protein (observed in neurons and glial cells) is conserved in brain phylogeny.