Influence of the SUMOylation pathway on adeno-associated virus vector transduction

Adeno-associated virus (AAV) is a member of the Parvoviridae family with a non-enveloped and icosahedral capsid structure. Recombinant AAVs (rAAV) are non-pathogenic with the low immunogenicity and broad cell/tissue tropism, thus AAV is wildly used as a gene therapy tool. Currently, many clinical trials involving AAV vectors are ongoing and the marketed drug Glybera® was approved in Europe in 2012, followed by the Luxturna by FDA approval in 2017. However, the limitation of this vector is the poor AAV transduction efficiency. To reveal the regulation of the host factors in AAV2 transduction, an RNAi screen was performed previously to identify host proteins interfering with AAV2 transduction. Sae2 and Ubc9, which are key enzymes of the SUMOylation pathway, were identified as restriction factors of AAV infection. Similar to the ubiquitination, SUMOylation is a post-translational protein modification catalyzed by an E1 activating enzyme (consisting of Sae1 and Sae2) and an E2 conjugating enzyme (Ubc9). Further investigations in this thesis confirmed that the impairment of SUMOylation via Sae2 or Ubc9 knockdown resulted in a higher AAV transduction efficiency, and AAV2 infection can also enhance the total SUMOylation activity of host cells. Moreover, SUMOylation affects the transduction of AAV vectors with single stranded DNA (ssAAV) and self-complementary DNA (scAAV). To determine the target of SUMOylation in the AAV life cycle, a pull-down assay was performed for AAV2 particles indicating that the AAV2 capsid protein is SUMOylated. Site-directed mutagenesis and modified virus transduction shows involvement of K142/143 and K169 of VP2 in capsid SUMOylation. In addition, the data suggests that the N-terminus of VP2 needs to be free, as addition of protein tags such as GFP or HA abolishes SUMOylation. This indicates that the AAV2 capsid SUMOylation has VP2 spatial structure requirements. Moreover, the observed increased AAV2 transduction in a Daxx knockout cell line indicates that Daxx is another restriction factor of AAV. Compared with wild type HeLa cell line, the enhancing affects after Ubc9 knockdown in Daxx knockout cell line was dramatically reduced, which means the Daxx protein and SUMOylation may work in the same or overlapping pathways. Thence, not only the AAV2 capsid protein, but also SUMOylated Daxx could regulate AAV transduction. AAV2 subcellular trafficking involves multiple steps. AAV2 vector DNA in the cell membrane and cytoplasmic fractions are not altered after Sae2 knockdown indicating that impairment of the SUMOylation-pathway cannot affect AAV binding and the intracellular transport and therefore have no influence on AAV transduction. Other than this, there are two possibilities for SUMOylated AAV2 particles to accumulate in the nucleus: SUMOylation pathway could restrict the number of particles that reach the nucleus and undergo transduction; Alternatively, SUMOylation could not affect the amount of AAV2 particles but instead enhance AAV transduction by promoting AAV uncoating and ssDNA release in the nucleus

Study of the Impact of Quality Management System on Chinese Baby Dairy Product Industry

The aim of this research is to propose an integrated framework (pre-production stage) based on critical examination of the impact of implementing QMS in the Chinese baby dairy product industry, with particular emphasis on its drivers, barriers, external issues and challenges, supply chain management, quality standards, legislation and regulations

Growth of millimeter-sized high-quality CuFeSe2_2 single crystals by the molten salt method and study of their semiconducting behavior

An eutectic AlCl$_3$/KCl molten salt method in a horizontal configuration was employed to grow millimeter-sized and composition homogeneous CuFeSe$_2$ single crystals due to the continuous growth process in a temperature gradient induced solution convection. The typical as-grown CuFeSe$_2$ single crystals in cubic forms are nearly 1.6$\times$1.2$\times$1.0 mm3 in size. The chemical composition and homogeneity of the crystals was examined by both inductively coupled plasma atomic emission spectroscopy and energy dispersive spectrometer with Cu:Fe:Se = 0.96:1.00:1.99 consistent with the stoichiometric composition of CuFeSe$_2$. The magnetic measurements suggest a ferrimagnetic or weak ferromagnetic transition below T$_C$ = 146 K and the resistivity reveals a semiconducting behavior and an abrupt increase below T$_C$

Individuals’ preference on reading pathways influences the involvement of neural pathways in phonological learning

IntroductionExisting behavioral and neuroimaging studies revealed inter-individual variability in the selection of the two phonological routes in word reading. However, it is not clear how individuals’ preferred reading pathways/strategies modulate the involvement of a certain brain region for phonological learning in a new language, and consequently affect their behavioral performance on phonological access.MethodsTo address this question, the present study recruited a group of native Chinese speakers to learn two sets of artificial language characters, respectively, in addressed-phonology training (i.e., whole-word mapping) and assembled-phonology training conditions (i.e., grapheme-to-phoneme mapping).ResultsBehavioral results showed that the more lexical pathways participants preferred, the better they performed on newly-acquired addressed characters relative to assembled characters. More importantly, neuroimaging results showed that participants who preferred lexical pathway in phonological access show less involvement of brain regions for addressed phonology (e.g., the bilateral orbitofrontal cortex and right pars triangularis) in the processing of newly-acquired addressed characters.ConclusionThese results indicated that phonological access via the preferred pathway required less neural resources to achieve better behavioral performance. These above results provide direct neuroimaging evidence for the influence of reading pathway preference on phonological learning

Chemical Basis of Interactions Between Engineered Nanoparticles and Biological Systems

A recently reported incident of severe pulmonary fibrosis caused by inhaled polymer nanoparticles in seven female workers obtained much attention. In addition to the release of ENM waste from industrial sites, a major release of ENMs to environmental water occurs due to home and personal use of appliances, cosmetics, and personal products, such as shampoo and sunscreen. Airborne and aqueous ENMs pose immediate danger to the human respiratory and gastrointestinal systems. ENMs may enter other human organs after they are absorbed into the bloodstream through the gastrointestinal and respiratory systems. Practically, a thorough understanding of the fundamental chemical interactions between nanoparticles and biological systems has two direct impacts. First, this knowledge will encourage and assist experimental approaches to chemically modify nanoparticle surfaces for various industrial or medicinal applications

Superconductivity in a new layered cobalt oxychalcogenide Na6_{6}Co3_{3}Se6_{6}O3_{3} with a 3d5d^{5} triangular lattice

Unconventional superconductivity in bulk materials under ambient pressure is extremely rare among the 3$d$ transition-metal compounds outside the layered cuprates and iron-based family. It is predominantly linked to highly anisotropic electronic properties and quasi-two-dimensional (2D) Fermi surfaces. To date, the only known example of the Co-based exotic superconductor was the hydrated layered cobaltate, Na$_{x}$CoO$_{2}\cdot$ yH$_{2}$O, and its superconductivity is realized in the vicinity of a spin-1/2 Mott state. However, the nature of the superconductivity in these materials is still an active subject of debate, and therefore, finding new class of superconductors will help unravel the mysteries of their unconventional superconductivity. Here we report the discovery of unconventional superconductivity at $\sim$ 6.3 K in our newly synthesized layered compound Na$_{6}$Co$_{3}$Se$_{6}$O$_{3}$, in which the edge-shared CoSe$_{6}$ octahedra form [CoSe$_{2}$] layers with a perfect triangular lattice of Co ions. It is the first 3$d$ transition-metal oxychalcogenide superconductor with distinct structural and chemical characteristics. Despite its relatively low $T_{c}$, material exhibits extremely high superconducting upper critical fields, $\mu_{0}H_{c2}(0)$, which far exceeds the Pauli paramagnetic limit by a factor of 3 - 4. First-principles calculations show that Na$_{6}$Co$_{3}$Se$_{6}$O$_{3}$ is a rare example of negative charge transfer superconductor. This new cobalt oxychalcogenide with a geometrical frustration among Co spins, shows great potential as a highly appealing candidate for the realization of high-$T_{c}$ and/or unconventional superconductivity beyond the well-established Cu- and Fe-based superconductor families, and opened a new field in physics and chemistry of low-dimensional superconductors

The association between socioeconomic status and health-related quality of life among young and middle-aged maintenance hemodialysis patients: multiple mediation modeling

ObjectiveTo explore the relationship between socioeconomic status (SES), illness perception, social functioning, and health-related quality of life (HRQoL) of young and middle-aged maintenance hemodialysis (MHD) patients and the internal mechanism of action.DesignA multicenter cross-sectional study.MethodsAn aggregate of 332 young and middle-aged MHD patients were enrolled from hemodialysis centers in four general hospitals in Guangzhou, Guangdong, China, from June to December 2022. The questionnaires used included one for general demographic data, the Brief Illness Perception Questionnaire (BIPQ), Social Dysfunction Screening Scale (SDSS), and the 12-item Short Form Health Survey (SF-12).ResultsBoth SES and HRQoL were negatively correlated with illness perception and social functioning, respectively. SES was positively correlated with HRQoL. Illness perception was positively correlated with social functioning. The indirect effects of illness perception and social functioning on the relationship between SES and HRQoL were 0.33 and 0.31, making up 41.06% and 38.91% of the sum. The chain indirect effect of illness perception and social functioning was 0.10, making up 12.59% of the total effect, while gender did not play a moderating role.ConclusionIllness perception and social functioning may independently and accumulatively mediate the association between SES and HRQoL. Nurses should consider developing individual intervention program for young and middle-aged MHD patients with low SES, focusing on establishing targeted counseling and health education strategies corresponding to illness perception and social functioning to help patients improve their HRQoL