The bonobo genome compared with the chimpanzee and human genomes

Two African apes are the closest living relatives of humans: the chimpanzee (Pan troglodytes) and the bonobo (Pan paniscus). Although they are similar in many respects, bonobos and chimpanzees differ strikingly in key social and sexual behaviours, and for some of these traits they show more similarity with humans than with each other. Here we report the sequencing and assembly of the bonobo genome to study its evolutionary relationship with the chimpanzee and human genomes. We find that more than three per cent of the human genome is more closely related to either the bonobo or the chimpanzee genome than these are to each other. These regions allow various aspects of the ancestry of the two ape species to be reconstructed. In addition, many of the regions that overlap genes may eventually help us understand the genetic basis of phenotypes that humans share with one of the two apes to the exclusion of the other.     

Thromboxane synthase mutations in an increased bone density disorder (Ghosal syndrome)

Studying consanguineous families with Ghosal hematodiaphyseal dysplasia syndrome (GHDD), a disorder of increased bone density, we identified mutations in TBXAS1, which encodes thromboxane synthase (TXAS). TXAS, an enzyme of the arachidonic acid cascade, produces thromboxane A(2) (TXA(2)). Platelets from subjects with GHDD showed a specific deficit in arachidonic acid-produced aggregation. We also found that TXAS and TXA(2) modulated expression of TNFSF11 and TNFRSF11B (encoding RANKL and osteoprotegerin (OPG), respectively) in primary cultured osteoblasts.     

Cyclophilin and peptidyl-prolyl cis-trans isomerase are probably identical proteins

The enzyme peptidyl-prolyl cis-trans isomerase (PPIase) was recently discovered in mammalian tissues and purified from porcine kidney. It catalyses the slow cis-trans isomerization of proline peptide (Xaa-Pro) bonds in oligopeptides and accelerates slow, rate-limiting steps in the folding of several proteins. Here, we report the N-terminal sequence of PPIase together with further chemical and enzymatic properties. The results indicate that this enzyme is probably identical to cyclophilin, a recently discovered mammalian protein which binds tightly to cyclosporin A (CsA). Cyclophilin is thought to be linked to the immunosuppressive action of CsA. The first 38 amino-acid residues of porcine PPIase and of bovine cyclophilin are identical and the two proteins both have a relative molecular mass of about 17,000 (ref. 7). The catalysis of prolyl isomerization in oligopeptides and of protein folding by PPIase are strongly inhibited in the presence of low levels of CsA. The activities of both PPIase and cyclophilin depend on a single sulphydryl group. At present it is unknown whether the inhibition of prolyl isomerase activity is related with the immunosuppressive action of CsA.     

A simple game for the study of trust in distributed systems

Trust is an important aspect of the design and analysis of secure distributed systems. It is often used informally to designate those portions of a system that must function correctly in order to achieve the desired outcome. But it is a notoriously diffcult notion to formalize. What are the properties of trust? How is it learned, propagated, and utilized successfully? How can it be modeled? How can a trust model be used to derive protocols that are effcient and reliable when employed in today’s expansive networks? Past work has been concerned with only a few of these issues, without concentrating on the need for a comprehensive approach to trust modeling. In this paper, we take a first step in that direction by studying an artificial community of agents that uses a notion of trust to succeed in a game against nature. The model is simple enough to analyze and simulate, but also rich enough to exhibit phenomena of real-life interactive communities. The model requires agents to make decisions. To do well, the agents are informed by knowledge gained from their own past experience as well as from the experience of other agents. Communication among agents allows knowledge to propagate faster through the network, which in turn can allow for a more successful community. We analyze the model from both a theoretical and an experimental point of view.     

Verhütung der Hitzekoagulation von Serumproteinen durch Zucker

Summary Sixteen individuals of different types of sugars have been investigated as to their ability of inhibiting the visible heat coagulation of serum. When bovine serum was diluted with an equal amount of water and maintained at 70° C during half an hour, the following sugars were able to prevent coagulation in a minimum concentration of 5% per volume:l-arabinose,d-ribose,l-ascorbic acid, and digitoxose.