Identification of a gene for an ancient cytokine, interleukin 15-like, in mammals; interleukins 2 and 15 co-evolved with this third family member, all sharing binding motifs for IL-15Rα

Interleukins 2 and 15 (IL-2 and IL-15) are highly differentiated but related cytokines with overlapping, yet also distinct functions, and established benefits for medical drug use. The present study identified a gene for an ancient third IL-2/15 family member in reptiles and mammals, interleukin 15-like (IL-15L), which hitherto was only reported in fish. IL-15L genes with intact open reading frames (ORFs) and evidence of transcription, and a recent past of purifying selection, were found for cattle, horse, sheep, pig and rabbit. In human and mouse the IL-15L ORF is incapacitated. Although deduced IL-15L proteins share only ~21 % overall amino acid identity with IL-15, they share many of the IL-15 residues important for binding to receptor chain IL-15Rα, and recombinant bovine IL-15L was shown to interact with IL-15Rα indeed. Comparison of sequence motifs indicates that capacity for binding IL-15Rα is an ancestral characteristic of the IL-2/15/15L family, in accordance with a recent study which showed that in fish both IL-2 and IL-15 can bind IL-15Rα. Evidence reveals that the species lineage leading to mammals started out with three similar cytokines IL-2, IL-15 and IL-15L, and that later in evolution (1) IL-2 and IL-2Rα receptor chain acquired a new and specific binding mode and (2) IL-15L was lost in several but not all groups of mammals. The present study forms an important step forward in understanding this potent family of cytokines, and may help to improve future strategies for their application in veterinarian and human medicine.

Hydraulic economy and logographic writing in ancient China: factor of topography

Chinese civilisation is characterised by two distinctive features – a strong centralised administration and the system of logographic writing. This paper investigates nature’s powerful impacts on human development, in terms of organisation and communication in ancient China. It argues that ancient China’s topography played a crucial role in the formation of ancient Chinese civilisation and its hydraulic economy pushed the state stronger than society, hence a strong centralised government emerged.

Burning books and burying scholars: on the policies of the short-lived Qin Dynasty in ancient China (221-207 BC)

In 221 BC, the battle-hardened warriors of the Qin state, the western frontier state and the most aggressive of the Warring States, subjugated the last of its rival states, thus establishing the Qin dynasty, with itscapital in Xianyang, near the modern Xi’an. The Qin dynasty is customarily regarded by Chinese and Western scholars as the beginning of a new age – the Chinese empire – that lasted until 1911 AD. The dynasty lasted only fifteen years. This study examines the main policies of the Qin dynasty and seeks to address the question what brought the quick downfall of the Qin rule. This paper takes the cultural and political contexts carefully into consideration, and argues that the Qin annexation of its rival states might be better understood as an end of an old era as much as a beginning of a new epoch.