The glycolytic enzyme, pyruvate kinase Pyk1 maintains telomere heterochromatin by phosphorylating histone H3T11 (H3pT11), which promotes SIR (silent information regulator) complex binding at telomeres and prevents autophagy-mediated Sir2 degradation. However, the exact mechanism of action for H3pT11 is poorly understood. Here, we report that H3pT11 directly inhibits Dot1-catalyzed H3K79 tri-methylation (H3K79me3) and uncover how this histone crosstalk regulates autophagy and telomere silencing. Mechanistically, Pyk1-catalyzed H3pT11 directly reduces the binding of Dot1 to chromatin and inhibits Dot1-catalyzed H3K79me3, which leads to transcriptional repression of autophagy genes and reduced autophagy. Despite the antagonism between H3pT11 and H3K79me3, they work together to promote the binding of SIR complex at telomeres to maintain telomere silencing. Furthermore, we identify Reb1 as a telomere-associated factor that recruits Pyk1-containing SESAME (Serine-responsive SAM-containing Metabolic Enzyme) complex to telomere regions to phosphorylate H3T11 and prevent the invasion of H3K79me3 from euchromatin into heterochromatin to maintain telomere silencing. Together, these results uncover a histone crosstalk and provide insights into dynamic regulation of silent heterochromatin and autophagy in response to cell metabolism.

Oceans have been proved to be an important resource due to their abundant reserves in oil and gas. However, because of the extent of oil exploration and development in recent years, the marine ecological environment has been increasingly affected. At present, the control and treatment of environmental pollution from offshore drilling both at home and abroad have focused on end-treatment after problems have already emerged. Nevertheless, preventative measures and appropriate control links has not been addressed. The main content of this study is to establish evaluation indexes of a "green" ocean drilling fluid system that will be environmentally friendly and applied to oilfields, such as the Bohai bay in the Shenli oil field. The results show that the recommended "green" ocean drilling fluid system has a good drilling performance, meets the requirements of drilling engineering and marine environmental protection, and achieves the source control of environmental contamination from offshore drilling. The environmental performance of this fluid is superior to sulphonated polymer mud drilling fluid and oil-based drilling fluids.

Oil-based drilling fluid is used more and more in the field of oil and gas exploration. However, because of unrecyclable treating agent and hard treatment conditions, the traditional treating technologies of waste oil-based drilling fluid have some defects, such as waste of resource, bulky equipment, complex treatment processes, and low oil recovery rate. In this work, switchable deoiling agent (SDA), as a novel surfactant for treatment of waste oil-based drilling fluid, was synthesized by amine, formic acid, and formaldehyde solution. With this agent, the waste oil-based drilling fluid can be treated without complex process and expensive equipment. Furthermore, the agent used in the treatment can be recycled, which reduces waste of resource and energy. The switch performance, deoiling performance, structural characterization, and mechanisms of action are studied. The experimental results show that the oil content of the recycled oil is higher than 96% and more than 93% oil in waste oil-based drilling fluid can be recycled. The oil content of the solid residues of deoiling is less than 3%.

Waste oil-based drilling fluids are hazardous wastes containing oil, heavy-metal and organic pollutants. However, the common treatment methods at home and abroad these methods not only waste many useful resources (because the oil is discarded rather than recovered) but also increase the pro-environment cost of oil companies. This paper develops useful recycling and safe disposal technology of waste oil-based drilling fluids from the perspective of utility, efficiency and economy, which not only recycle useful oil but also reuse and dispose of the rest of mud and waste drilling fluids. The rate of recovery is greater than 90%, and the quality of the recycled oil is very good and meets the requirement of -10 # diesel of cars in GB/T 19147-2003. The concentrations of oil, COD (chemical oxygen demand) and heavy metals in liquid of the processed mud are lower than the secondary standard number in GB8978-1996. The treated wastewater meets the requirements of sewage comprehensive emission.

No abstract