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Professor Roger D. Komberg — 2006 Nobel Prize in Chemistry.

Scientists in Guangzhou engineered pig model of Huntington’s disease

Heart-on-a-chip device to aid drug screening

Nanozymes to target tumor cells

Cancer stem cell therapy breakthrough

Hong Kong researchers invent antibody drug for HIV-I prevention

SNAB technology to mark tumor cells during cancer surgeries

Draft genome of tea plant sequenced

International Earth BioGenome Project proposed to sequence DNA of all known species on Earth

Chinese pharma regulatory reforms will help to attract foreign investment

Merck receives patent for CRISPR Technology in China

STA Pharmaceuticals to build new R&D center in Shanghai

Archaea, bacteria and eukaryotes represent the main kingdoms of life. Is there any trend for amino acid compositions of proteins found in full genomes of species of different kingdoms? What is the percentage of totally unstructured proteins in various proteomes? We obtained amino acid frequencies for different taxa using 195 known proteomes and all annotated sequences from the Swiss–Prot data base. Investigation of the two data bases (proteomes and Swiss–Prot) shows that the amino acid compositions of proteins differ substantially for different kingdoms of life, and this difference is larger between different proteomes than between different kingdoms of life. Our data demonstrate that there is a surprisingly small selection for the amino acid composition of proteins for higher organisms (eukaryotes) and their viruses in comparison with the "random" frequency following from a uniform usage of codons of the universal genetic code. On the contrary, lower organisms (bacteria and especially archaea) demonstrate an enhanced selection of amino acids. Moreover, according to our estimates, 12%, 3% and 2% of the proteins in eukaryotic, bacterial and archaean proteomes are totally disordered, and long (> 41 residues) disordered segments are found to occur in 16% of arhaean, 20% of eubacterial and 43% of eukaryotic proteins for 19 archaean, 159 bacterial and 17 eukaryotic proteomes, respectively. A correlation between amino acid compositions of proteins of various taxa, show that the highest correlation is observed between eukaryotes and their viruses (the correlation coefficient is 0.98), and bacteria and their viruses (the correlation coefficient is 0.96), while correlation between eukaryotes and archaea is 0.85 only.

All complex life on Earth is composed of ‘eukaryotic’ cells. Eukaryotes arose just once in 4 billion years, via an endosymbiosis — bacteria entered a simple host cell, evolving into mitochondria, the ‘powerhouses’ of complex cells. Mitochondria lost most of their genes, retaining only those needed for respiration, giving eukaryotes ‘multi-bacterial’ power without the costs of maintaining thousands of complete bacterial genomes. These energy savings supported a substantial expansion in nuclear genome size, and far more protein synthesis from each gene.

The concept of the three domains of life (the bacteria, archaea and eukaryotes) goes back to Carl Woese in 1990¹. Most scientists now see the eukaryotes (cells with a true nucleus) as a secondary domain, derived from bacteria and archaea via an endosymbiosis². That makes the last universal common ancestor of life (LUCA) the ancestor of bacteria and archaea³. While these domains are strikingly different in their genetics and biochemistry⁴, they are nearly indistinguishable in their cellular morphology — historically, both groups have been classed as prokaryotes. In terms of their metabolic versatility and molecular machinery, prokaryotes are if anything more sophisticated than eukaryotes⁵. Yet despite an exhaustive search of genetic sequence space in virtually infinite populations over four billion years, neither domain evolved morphological complexity to compare with eukaryotes⁵. The evolutionary path to morphological complexity does not seem to depend on genetic information alone⁶. The most plausible explanation is that physical constraints stemming from the topological structure of prokaryotes blocked the evolution of morphological complexity in prokaryotes, and that the endosymbiosis at the origin of eukaryotes relieved these constraints⁶. In this lecture, I shall argue that the dependence of all life on electrical charges across membranes to generate energy explains the structural constraints on prokaryotes, and the escape from these constraints in eukaryotes⁷.

Lipid mediator is the collective term for prostanoids, leukotrienes, lysophospholipids, platelet-activating factor, endocannabinoids and other bioactive lipids, that are involved in various physiological functions including inflammation, immune regulation and cellular development. They act by binding to their ligand-specific G-protein coupled receptors (GPCRs). Since 1990's a number of lipid GPCRs have been cloned in humans, with a few more identified in other vertebrates. However, the conservation of these receptors has been poorly investigated in other eukaryotes. Herein we performed a phylogenetic analysis by collecting their orthologs in 13 eukaryotes with complete genomes. The analysis shows that orthologs for prostanoid receptors are likely to be conserved in the 13 eukaryotes. In contrast, those for lysophospholipid and cannabinoid receptors appear to be conserved only in vertebrates and chordates. Receptors for leukotrienes and other bioactive lipids are limited to vertebrates. These results indicate that the lipid mediators and their receptors have coevolved with the development of highly modulated physiological functions such as immune regulation and the formation of the central nervous system. Accordingly, examining the presence and role of lipid mediator GPCR orthologs in invertebrate species can provide insight into the development of fundamental biological processes across diverse taxa.

All complex life on Earth is composed of ‘eukaryotic’ cells. Eukaryotes arose just once in 4 billion years, via an endosymbiosis — bacteria entered a simple host cell, evolving into mitochondria, the ‘powerhouses’ of complex cells. Mitochondria lost most of their genes, retaining only those needed for respiration, giving eukaryotes ‘multi-bacterial’ power without the costs of maintaining thousands of complete bacterial genomes. These energy savings supported a substantial expansion in nuclear genome size, and far more protein synthesis from each gene.