Search

Horizontal gene transfer (HGT), a mechanism that shares genetic material between the host and donor from separated offspring branches, has been described as a means of producing novel and beneficial phenotypes for the host organisms. However, in molluscs, the second most diverse group, the existence of HGT is still controversial. In the present study, 12 HGT genes were identified from California two-spot octopus Octopus bimaculoides based on a similarity search, phylogenetic construction, gene composition analysis and PCR (Polymerase Chain Reaction) validation. Based on the phylogenetic topologies, ten HGT genes were identified to have been transferred into the possible molluscan ancestor, possibly before its radiation. Furthermore, most of the donor organisms were predicted to be familiar bacteria in marine environments. These horizontally transferred genes were under a strong negative selection and could be transcribed in octopus functionally. The predicted biochemical functions of these genes include metabolism, neurotransmission, immune defense and tissue integrity. Seven Zn-metalloproteinases were validated as the main type of HGT genes in octopus with divergent motif composition, intron presence and phylogenetic relationship to the endogenous ones. Furthermore, the functions of Zn-metalloproteinase were predicted to be responsible for immune defense and tissue remolding. Three HGT genes were distributed mainly in the nervous system and were predicted to regulate the neurotransmission through glia-neuronal interactions. The results collectively indicated the existence of HGT in molluscs and its potential contribution to the evolution of octopus with regards to functional innovation and adaptability.

In this work, two different liquid charging methods are designed to use in different pump-assisted capillary phase change loops. The aim of present work is to investigate the impact of the liquid charging processes on the operational characteristics of the loop. For the two pump-assisted capillary loops, the loop structure and the main parameters of the components keep the same. In addition, methanol is used as the working fluid in both loops. The experimental results demonstrate that the vaporization temperature of the loop 2 has a notable decrease due to the optimized liquid charging process. The corresponding thin film boiling in the evaporator of loop 2 occurs even though a lower heat load is applied. Meanwhile, with a high heat load applied to loop 2, the unique vapor superheating in the vapor chamber is observed. Comparing the heat transfer performance between the loops, the loop 2 presents a superior capability at low heat loads, while loop 1 can transfer a higher heat load for the upper bound of the heater surface temperature. For both of the loops, the evaporator thermal resistance, if not included the heat load of 10 W at a pumping power of 2 W in loop 2, varies between 0.15 K/W and 0.3 K/W.