Myelogenesis and estimation of the number of axons in the anterior commissure of the chick (Gallus gallus)

Summary By use of light- and electron microscopy the anterior commissure of the chick was studied at different times during development. Between the 19th day of incubation and the 35th day after hatching the cross-sectional area of the anterior commissure, as determined from mid-sagittal sections, undergoes a 6-fold increase in size. Thereafter the area remains fairly constant. The total number of fibres in the anterior commissure was estimated to be 89000. The full complement of fibres is already present by the 19th day of incubation. Myelogenesis occurs mainly between the 19th day of incubation and the 35th day after hatching, concomitant with the increase in cross-sectional area. From the 35th day after hatching, myelinated fibres comprise approximately 40% of the total number of fibres. The median diameter of unmyelinated fibres is about 0.35–0.40 m. The median diameters of myelinated axons and fibres are 0.8–1.0 m and 1.1–1.3 m, respectively.     

暗腹雪鸡与海兰褐鸡血液生理生化指标的比较

为了解暗腹雪鸡（Tetraogallus himalayensis）正常血液生理生化特性,本文对暗腹雪鸡21项血液生理生化指标进行了测定,并与海兰褐鸡（Gallus gallus domesticus var. Hyline）进行了比较。测定结果,暗腹雪鸡的红细胞纵径及横纵径乘积、平均红细胞容积及平均红细胞血红蛋白含量极显著大于海兰褐鸡（P<0.01）;暗腹雪鸡天冬氨酸氨基转移酶和胆固醇含量均极显著高于海兰褐鸡（P<0.01）。其他各项血液生理生化指标两禽种间之间差异不显著。实验结果表明,暗腹雪鸡血液生理生化指标与家养蛋鸡之间有一定差异,暗腹雪鸡对高原低氧环境有较强的适应性可能与其红细胞体积较大、平均红细胞容积及平均红细胞血红蛋白含量较高有一定关系。     

Detection of sequence polymorphisms in red junglefowl and White Leghorn ESTs

Over 16,000 high quality expressed sequence tags (ESTs) from red junglefowl (RJ) and White Leghorn (WL) brain and testis cDNA libraries were generated. Here, we have used this resource for detection of single nucleotide polymorphisms (SNPs), and also completed full-length sequencing of 46 pairs of clones, representing the same gene from both the RJ and WL libraries. From the main set of ESTs, which were assembled using Phrap, 746 putative SNPs were identified, of which 76% were transitions and 24% were transversions. A subset of SNPs was evaluated by sequence analysis of five RJ and five WL birds. Nine of 12 SNPs were verified in this limited sample, suggesting that a majority of the putative polymorphisms documented in this study represent real SNPs. During full-length sequencing of the 46 RJ/WL clones 100 SNPs were identified, which translated to a frequency of 1.90 SNPs/1000 bp. The number of transitions and transversions were 77% and 23%, respectively, and the proportion of non-synonymous vs. synonymous SNPs was 20% and 80%, respectively. Four large insertions/deletions were identified between the RJ and WL full-length sequences, and they appear to represent different splice variants.     

Colour preferences and colour vision in poultry chicks

The dramatic colours of biological communication signals raise questions about how animals perceive suprathreshold colour differences, and there are long-standing questions about colour preferences and colour categorization by non-human species. This study investigates preferences of foraging poultry chicks (Gallus gallus) as they peck at coloured objects. Work on colour recognition often deals with responses to monochromatic lights and how animals divide the spectrum. We used complementary colours, where the intermediate is grey, and related the chicks' choices to three models of the factors that may affect the attractiveness. Two models assume that attractiveness is determined by a metric based on the colour discrimination threshold either (i) by chromatic contrast against the background or (ii) relative to an internal standard. An alternative third model is that categorization is important. We tested newly hatched and 9-day-old chicks with four pairs of (avian) complementary colours, which were orange, blue, red and green for humans. Chromatic contrast was more relevant to newly hatched chicks than to 9-day-old birds, but in neither case could contrast alone account for preferences; especially for orange over blue. For older chicks, there is evidence for categorization of complementary colours, with a boundary at grey.     

Reptilian transferrins: evolution of disulphide bridges and conservation of iron-binding center

Transferrins, found in invertebrates and vertebrates, form a physiologically important family of proteins playing a major role in iron acquisition and transport, defense against microbial pathogens, growth and differentiation. These proteins are bilobal in structure and each lobe is composed of two domains divided by a cleft harboring an iron atom. Vertebrate transferrins comprise of serotransferrins, lactoferrins and ovotransferrins. In mammals serotransferrins transport iron in physiological fluids and deliver it to cells, while lactoferrins scavenge iron, limiting its availability to invading microbes. In oviparous vertebrates there is only one transferrin gene, expressed either in the liver to be delivered to physiological fluids as serotransferrin, or in the oviduct with a final localization in egg white as ovotransferrin. Being products of one gene sero- and ovotransferrin are identical at the amino-acid sequence level but with different, cell specific glycosylation patterns. Our knowledge of the mechanisms of transferrin iron binding and release is based on sequence and structural data obtained for human serotransferrin and hen and duck ovotransferrins. No sequence information about other ovotransferrins was available until our recent publication of turkey, ostrich, and red-eared turtle (TtrF) ovotransferrin mRNA sequences [Ciuraszkiewicz, J., Olczak, M., Watorek, W., 2006. Isolation, cloning and sequencing of transferrins from red-eared turtle, African ostrich and turkey. Comp. Biochem. Physiol. 143 B, 301-310]. In the present paper, ten new reptilian mRNA transferrin sequences obtained from the Nile crocodile (NtrF), bearded dragon (BtrF), Cuban brown anole (AtrF), veiled and Mediterranean chameleons (VtrF and KtrF), sand lizard (StrF), leopard gecko (LtrF), Burmese python (PtrF), African house snake (HtrF), and grass snake (GtrF) are presented and analyzed. Nile crocodile and red-eared turtle transferrins have a disulphide bridge pattern identical to known bird homologues. A partially different disulphide bridge pattern was found in the Squamata (snakes and lizards). The possibility of a unique interdomain disulphide bridge was predicted for LtrF. Differences were found in iron-binding centers from those of previously known transferrins. Substitutions were found in the iron-chelating residues of StrF and TtrF and in the synergistic anion-binding residues of NtrF. In snakes, the transferrin (PtrF, HtrF and GtrF) N-lobe "dilysine trigger" occurring in all other known transferrins was not found, which indicates a different mechanism of iron release.     

Proteomic analysis of the Gallus gallus embryo at stage-29 of development

The chicken (Gallus gallus) is one of the primary models for embryological and developmental studies. In order to begin to understand the molecular mechanisms underlying the normal and abnormal development of the chicken, we used 2-DE to construct a whole-embryo proteome map. Proteins were separated by IEF on IPG strips, and by 11% SDS-PAGE) gels. Protein identification was performed by means of PMF with MALDI-TOF-MS. In all, 105 protein spots were identified, 35 of them implicated in embryo development, 10 related with some diseases, and 16, finally, being proteins that have never been identified, purified or characterized in the chicken before. This map will be updated continuously and will serve as a reference database for investigators, studying changes at the protein level under different physiological conditions.