Basic properties and exploitation strategies of source rock strata

Source rock strata are filled and aggregated with large-scale continuous hydrocarbon resources, including significant volumes of in-place retained, short-distance migrated and potentially generated hydrocarbons. Source rock strata simultaneously possess the properties of reservoirs and hydrocarbon source rocks, known as source-reservoir coexisting systems. Reservoir properties refer to the physical properties concerning the storage and transmission of oil and gas, while hydrocarbon source rock properties refer to the physicochemical properties related to governing the generation, retention and expulsion of oil and gas in the source rock strata. These properties fundamentally determine the technical path for the successful exploitation of petroleum and natural gas in the source rock strata. With regard to reservoir properties, in-depth research and development of the advanced energy-storing fracturing technology can aid the construction of complex fracture networks to overcome the limitations in the connectivity properties of source rock strata. Focusing on the hydrocarbon source rock properties, an underground in-situ conversion technology should be created and developed to alleviate the shortcomings of organic matter quantity and maturity properties of the source rock strata. Furthermore, selecting the appropriate exploitation path based on the property characteristics can promote the achievement of commercial and sustainable development of oil and gas in the source rock strata.Document Type: PerspectiveCited as: Yang, Z., Zou, C., Fan, Y., Wu, S., Liu, H., Wei, Q. Basic properties and exploitation strategies of source rock strata. Advances in Geo-Energy Research, 2023, 10(2): 77-83. https://doi.org/10.46690/ager.2023.11.0

Minimal Essential Human Factor VIII Alterations Enhance Secretion and Gene Therapy Efficiency

One important limitation for achieving therapeutic expression of human factor VIII (FVIII) in hemophilia A gene therapy is inefficient secretion of the FVIII protein. Substitution of five amino acids in the A1 domain of human FVIII with the corresponding porcine FVIII residues generated a secretion-enhanced human FVIII variant termed B-domain-deleted (BDD)-FVIII-X5 that resulted in 8-fold higher FVIII activity levels in the supernatant of an in vitro cell-based assay system than seen with unmodified human BDD-FVIII. Analysis of purified recombinant BDD-FVIII-X5 and BDD-FVIII revealed similar specific activities for both proteins, indicating that the effect of the X5 alteration is confined to increased FVIII secretion. Intravenous delivery in FVIII-deficient mice of liver-targeted adeno-associated virus (AAV) vectors designed to express BDD-FVIII-X5 or BDD-FVIII achieved substantially higher plasma FVIII activity levels for BDD-FVIII-X5, even when highly efficient codon-optimized F8 nucleotide sequences were employed. A comprehensive immunogenicity assessment using in vitro stimulation assays and various in vivo preclinical models of hemophilia A demonstrated that the BDD-FVIII-X5 variant does not exhibit an increased immunogenicity risk compared to BDD-FVIII. In conclusion, BDD-FVIII-X5 is an effective FVIII variant molecule that can be further developed for use in gene- and protein-based therapeutics for patients with hemophilia A

Quantitative characterization and main controlling factors of shale oil occurrence in Permian Fengcheng Formation, Mahu Sag, Junggar Basin

The characteristics and controlling factors of shale oil occurrence in Permian Fengcheng Formation of the Mahu Sag, Junggar Basin are complex, making occurrence state identification and quantitative characterization difficult. It is of great significance to clarify the occurrence characteristics and controlling factors of shale oil for selecting sweet spots. In order to characterize the content of shale oil in different occurrence states, some shale samples in the central and slope areas of the sag were extracted step by step, and a quantitative characte-rization experiment method of shale oil in different occurrence states was established, obtaining the contents of free light hydrocarbon, free heavy hydrocarbon and adsorbed hydrocarbon, respectively. Based on the study of organic geochemistry and reservoir micro-characteristics, the following conclusions are obtained. Due to the low TOC and clay contents in the study area, the shale oil in the Fengcheng Formation mainly occurs in dissociative state and has the least adsorbed hydrocarbon content. Shale oil occurs mostly on mineral surface and in kerogen in oil film state, heavy hydrocarbons usually occur in shale with large micropore specific surface area, and macropores are the main occurrence space of free oil. With the increase of organic matter abundance and pore size, the shale oil content in different occurrence states shows an increasing trend, indicating that the higher organic matter abundance and larger pore size are conducive to shale oil enrichment. Maturity can greatly affect the adsorption capacity of fluid in shale, and the higher the maturity of organic matter, the higher the proportion of free hydrocarbons and the lower the proportion of adsorbed hydrocarbons. The increase of specific surface area promotes the enrichment of adsorbed oil and free heavy hydrocarbons, and restricts the enrichment of free light hydrocarbons, indicating that the specific surface area of mesoporous pores has a controlling effect on the adsorption capacity of shale oil, i.e., the larger the specific surface area, the stronger the adsorption capacity of shale oil. The relevant research and recognition can provide a basis for selecting sweet spots and evaluating the benefits of shale oil exploitation in the study area

Cytotoxic shornephines and asterresins from the hydrothermal vent associated fungus Aspergillus terreus CXX-158-20

Wei, Jihua, Chen, Xuexia, Ge, Yichao, Yin, Qizhao, Ma, Yihan, Zhang, Zunjing, Wu, Xiaodan, Hong, Kui, Wu, Bin (2023): Cytotoxic shornephines and asterresins from the hydrothermal vent associated fungus Aspergillus terreus CXX-158-20. Phytochemistry (113479) 205: 1-11, DOI: 10.1016/j.phytochem.2022.113479, URL: http://dx.doi.org/10.1016/j.phytochem.2022.11347

Citrinin Monomer, Trimer, and Tetracyclic Alkaloid Derivatives from the Hydrothermal Vent-Associated Fungus Penicillium citrinum TW132-59

Five new unusual citrinin-derived alkaloids with a tetracyclic core, citrinidines A–E (1–5), two new amide alkaloids, methyl (2S,8E)-1′-(2-methyl-3-oxodec-8-enamido) butanoate (6) and (2S,8E)-2-methyl-3-oxodec-8-enamide (7), a new unusual citrinin trimer, tricitrinol C (8), a new citrinin acetal-ketal derivative, citrininol (9), together with four known citrinin monomers (10–13), and three known citrinin dimers (14–16), were isolated from the fermentation of hydrothermal vent-associated fungus Penicillium citrinum TW132-59. Their structures were unambiguously determined by nuclear magnetic resonance (NMR), mass spectrometry, Mosher′s method, 13C NMR calculation in combination with DP4+, and ECD calculations. A plausible biosynthetic pathway of all new compounds (1–9) was proposed. Citrinin trimer (8) exhibited potent cytotoxicity activity with an IC50 value of 1.34 ± 0.11 μM, and compounds 1 and 15 showed moderate cytotoxicity with IC50 values of 17.50 ± 1.43 and 9.45 ± 0.55 μM, respectively, against A549 cell line

A Robust System for Production of Superabundant VP1 Recombinant AAV Vectors

Recombinant adeno-associated viral (rAAV) vectors have been widely used in human gene therapy. One major impediment to its broad application is the inability to produce high-quality vectors in mass quantity. Here, an efficient and scalable suspension cell culture system for the production of rAAV vectors is described. In this system, the AAV trans factors, Rep78, Rep52, VP1, VP2, and VP3, were stably integrated into a single vaccinia virus carrier by maximizing the use of alternative codons between genes with identical amino acids, and the cis rAAV genome was carried by an E1/E3 gene-deleted adenovirus. Infection of improved, E1 integrated, suspension-cultured cells with these two viral vectors resulted in the robust production of rAAV vectors. The newly enhanced system can consistently produce ∼1 × 1015 genome containing rAAV vectors per liter of suspension cells. Moreover, the capsid composition of rAAV vectors produced by this system is markedly different from those produced using the traditional system in that the VP1 protein is more abundant than the VP2 protein (19:1 versus 1:1). The unique VP1 superabundant rAAV vectors produced in this new system exhibited improved transduction in vivo after intravitreal injection