Reconstruction of gross avian genome structure,organization and evolution suggests that the chicken lineage most closely resembles the dinosaur avian ancestor

Background

The availability of multiple avian genome sequence assemblies greatly improves our ability to define overall genome organization and reconstruct evolutionary changes. In birds, this has previously been impeded by a near intractable karyotype and relied almost exclusively on comparative molecular cytogenetics of only the largest chromosomes. Here, novel whole genome sequence information from 21 avian genome sequences (most newly assembled) made available on an interactive browser (Evolution Highway) was analyzed.

Results

Focusing on the six best-assembled genomes allowed us to assemble a putative karyotype of the dinosaur ancestor for each chromosome. Reconstructing evolutionary events that led to each species’ genome organization, we determined that the fastest rate of change occurred in the zebra finch and budgerigar, consistent with rapid speciation events in the Passeriformes and Psittaciformes. Intra- and interchromosomal changes were explained most parsimoniously by a series of inversions and translocations respectively, with breakpoint reuse being commonplace. Analyzing chicken and zebra finch, we found little evidence to support the hypothesis of an association of evolutionary breakpoint regions with recombination hotspots but some evidence to support the hypothesis that microchromosomes largely represent conserved blocks of synteny in the majority of the 21 species analyzed. All but one species showed the expected number of microchromosomal rearrangements predicted by the haploid chromosome count. Ostrich, however, appeared to retain an overall karyotype structure of 2n = 80 despite undergoing a large number (26) of hitherto un-described interchromosomal changes.

Conclusions

Results suggest that mechanisms exist to preserve a static overall avian karyotype/genomic structure, including the microchromosomes, with widespread interchromosomal change occurring rarely (e.g., in ostrich and budgerigar lineages). Of the species analyzed, the chicken lineage appeared to have undergone the fewest changes compared to the dinosaur ancestor.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1060) contains supplementary material, which is available to authorized users.     

Copigments in the blueing of sepal colour of Hydrangea macrophylla

From blue sepals of Hydrangea macrophylla, copigments which show a blueing effect on the hydrangea anthocyanin were isolated and identified as 3-p-coumaroylquinic acid and 3-caffeoylquinic acid. 5-Caffeoylquinic acid (chlorogenic acid) which was also found in the blue sepals, however, did not show such a blueing effect though it acted as a copigment. Likewise, the 4-esters of p-coumaroyl- and caffeoylquinic acids (not found in sepals) produced purple rather than blue colours. The facts suggest that the stereostructures of 3-p-coumaroyl- and 3-caffeoylquinic acids are effective for molecular interaction between the p-coumaroyl or caffeoyl residue in the compounds and the anthocyanin. The anthocyanin in red and blue sepals of hydrangea was confirmed to be delphinidin 3-monoglucoside.     

Nitrotyrosine formation and its role in various pathological conditions

The formation of peroxynitrite and nitrotyrosine was examined in a variety of in vitro and in vivo animal models and its relation to cell or tissue damage was examined. In polymorphonuclear leukocyte (PMN)-induced injury to cardiac myocytes or endothelial cells, activated PMN produced peroxynitrite. Peroxynitrite appears to be responsible for the injury but it was not a major mediator of endothelial cell injury. In the experiment of ischemia-reperfusion injury of the rat brain nitrotyrosine was formed in the peri-infarct and core-of infarct regions. The degradation curve of nitrotyrosine revealed that its t1/2 was about 2.2 hours. In the radiation-induced lung injury of rats, nitrotyrosine was also formed but it was not the sole mechanism for the injury. Levels of nitrotyrosine correlated with the severity of myocardial dysfunction in the canine model of cytokine-induced cardiac injury. Inhibition of NO generation abolished the formation of peroxynitrite and nitrotyrosine in all experiments. In conclusion; although nitrotyrosine is formed in a variety of pathological conditions where the generation of NO is increased, its presence does not always correlate with the severity of injury.     

Force–velocity,force–power relationships of bilateral and unilateral leg multi-joint movements in young and elderly women

The present study investigated force–velocity and force–power relationships of bilateral and unilateral knee-hip extension movement in young and elderly women. Twelve healthy young (age, 19–31 yr) and 12 healthy elderly (age, 60–82 yr) women performed bilateral and unilateral knee-hip extension movements on the dynamometer against loads controlled by the servo system. Under the isotonic force condition, force–velocity relationships were measured. The maximum isometric force (F_max), unloaded velocity (V_max) and power output (P_max) of the movements were calculated from extrapolating force–velocity and force–power relationships. F_max and P_max of bilateral and unilateral knee-hip extension movements were 20–30% lower in elderly than in young women. On the other hand, there were no significant differences in V_max between young and elderly women and between bilateral and unilateral movements. Bilateral deficit was larger as the generation of force was larger in both young and elderly women. Also, bilateral deficit of F_max and P_max were not different between young and elderly women. The results were that lower maximum power output of bilateral and unilateral leg multi-joint movements in elderly women did not depend on the intrinsic shortening velocity of muscle action, but largely on reduction in force generating capacity. This suggests the importance of preventing a loss of force generating capacity of muscles during leg multi-joint movements in elderly women.     

Oocyte nucleus controls progression through meiotic maturation

We analyzed progression through the meiotic maturation in oocytes manipulated to replace the prophase oocyte nucleus with the nucleus from a cumulus cell, a pachytene spermatocyte or the pronucleus from a fertilized egg. Removal of the oocyte nucleus led to a significant reduction in histone H1 kinase activity. Replacement of the oocyte nucleus by a pronucleus followed by culture resulted in premature pseudomeiotic division and occasional abnormal cytokinesis; however, histone H1 kinase activity was rescued, microtubules formed a bipolar spindle, and chromosomes were condensed. In addition to the anomalies observed after pronuclear transfer, those after transfer of the nucleus from a cumulus cell or spermatocyte included a dramatically impaired ability to form the bipolar spindle or to condense chromosomes, and histone H1 kinase activity was not rescued. Expression of a cyclin B-YFP in enucleated oocytes receiving the cumulus cell nucleus rescued histone H1 kinase activity, but spindle formation and chromosome condensation remained impaired, indicating a pleiotropic effect of oocyte nucleus removal. However, when the cumulus cell nucleus was first transformed into pronuclei (transfer into a metaphase II oocyte followed by activation), such pronuclei supported maturation after transfer into the oocyte in a manner similar to that of normal pronuclei. These results show that the oocyte nucleus contains specific components required for the control of progression through the meiotic maturation and that some of these components are also present in pronuclei.     

Acute responses of regional vascular conductance to oral ingestion of fructose in healthy young humans

Background

Recently, it was reported in healthy young subjects that fructose containing drinks increased blood pressure acutely, without any apparent change in total vascular conductance (TVC). However, because it is well known that the splanchnic vasculature is dilated by oral fructose ingestion, it is assumed to be the concomitant vasoconstriction in other peripheral region(s) that is responsible for this finding. Thus, the purpose of this study was to determine the acute response of regional VC to oral fructose ingestion in young healthy humans.

Results

In 12 healthy young subjects, mean arterial blood pressure (MAP), heart rate, cardiac output, and blood flow (BF) in the superior mesenteric (SMA), brachial (BA), and popliteal (PA) arteries, in addition to forearm skin BF, were measured continuously for 2 h after ingestion of 400 ml fructose solution (containing 50 g fructose). Regional VC was calculated as BF/MAP. MAP increased for 120 min after fructose ingestion without any change in TVC. While VC in the SMA was elevated after ingestion, VC in BA and PA and forearm skin decreased.

Conclusions

While TVC was apparently unchanged during the 2 h after fructose ingestion, there were coincident changes in regional VCs in the peripheral circulation, but no net change in TVC.     

Glucagon-related peptides in the rat hypothalamus

Summary Immunohistochemically, nerve fibers and terminals reacting with anti-N-terminal-specific but not with anti-C-terminal-specific glucagon antiserum were observed in the following rat hypothalamic regions: paraventricular nucleus, supraoptic nucleus, anterior hypothalamus, arcuate nucleus, ventromedial hypothalamic nucleus and median eminence. Few fibers and terminals were demonstrated in the lateral hypothalamic area and dorsomedial hypothalamic nucleus. Radioimmunoassay data indicated that the concentration of gut glucagon-like immunoreactivity was higher in the ventromedial nucleus than in the lateral hypothalamic area. In food-deprived conditions, this concentration increased in both these parts. This was also verified in immunostained preparations in which a marked enhancement of gut glucagon-like immunoreactivity-containing fibers and terminals was observed in many hypothalamic regions. Several immunoreactive cell bodies were found in the ventromedial and arcuate nuclei of starved rats. Both biochemical and morphological data suggest that glucagon-related peptides may act as neurotransmitters or neuromodulators in the hypothalamus and may be involved in the central regulatory mechanism related to feeding behavior and energy metabolism.     

Degradative pathway of p-aminoazobenzene by Bacillus subtilis

Summary p-Aminoazobenzene was degraded by Bacillus subtilis to aniline and p-phenylenediamine by reductive fission of an azo bond. The aniline was then acetylated to acetanilide while the p-phenylenediamine underwent 2 successive acetylations to yield p-aminoacetanilide and p-phenylenediacetanilide. In addition, another pathway was found in Bacillus subtilis in which p-aminoazobenzene was metabolised to p-acetamidoazobenzene.