Acceptor Site Research Articles

A new colorimetric sensor based on semithiocarbazone for some anions: 2-(1,3-dioxo-1,3-dihydro-2H-inden-2-ylidene)-N-phenylhydrazine-1-carbothioamide

Carbazones are molecules containing important functional groups in designing anion chemosensors due to proton donor and acceptor sites in their structures. In this paper, we synthesize a novel colorimetric receptor with 1,3-dioxo-indene and thiosemicarbazone moieties by the reaction of ninhydrin and 4-phenyl-thiosemicarbazide in quantitative yield. We then identify its structure by means of FT-IR, $^{1}$H-NMR, $^{13}$C-NMR, and MS spectroscopic techniques. Moreover, we observe the reaction of the title compound with biologically important F$^¯$, OAc$^¯$, CN$^¯$, H2PO4$^¯$, and OH$^¯$ anions in the presence of other anions, such as Cl$^¯$, Br$^¯$, I$^¯$, SCN$^¯$, and OCl$^¯$ in dimethylsulfoxide solution through a color change from yellow to orange-red that can easily be distinguished even by the naked eye under ambient light. Finally, we evaluate the anion-sensing ability of the title compound via UV-vis spectroscopic studies.

Characterisation of TcFUT1, a mitochondrial fucosyltransferase from Trypanosoma cruzi

Previous work has shown that the TbFUT1 and LmjFUT1 genes encode essential fucosyltransferases located inside the single mitochondria of the protozoan parasites Trypanosoma brucei and Leishmania major, respectively. However, nothing was known about the orthologous gene TcFUT1 or its gene product in Trypanosoma cruzi, aetiological agent of Chagas disease. In this study, we describe the overexpression of TcFUT1 with a C-terminal 6xMyc epitope tag in T. cruzi epimastigote cells. Overexpressed and immunoprecipitated TcFUT1–6xMyc was used to demonstrate enzymatic activity and to explore substrate specificity. This defined TcFUT1 as a GDP-Fuc : βGal α1–2 fucosyltransferase with a strict requirement for acceptor glycans with non-reducing terminal Galβ1–3GlcNAc structures. This differs from the specificity of the T. brucei orthologue TbFUT1, which can also tolerate non-reducing terminal Galβ1–4GlcNAc and Galβ1–4Glc acceptor sites. Immunofluorescence microscopy using α-Myc tag antibodies also showed a mitochondrial location for TcFUT1 in T. cruzi epimastigote cells. Collectively, these results are like those described for TbFUT1 and LmjFUT1 from T. brucei and L. major, suggesting that FUT1 gene products have conserved function for across the trypanosomatids and may share therapeutic target potential.

(Invited) Synthesis and Photophysical Properties of Cyclometalated Iridium(III) Complexes Having Arylborane Units Toward the Photoreaction

Cyclometalated iridium(III) complexes are known to show intense absorption and bright phosphorescence at room temperature and have been applied to photosensitizer and light-emitting materials. For such applications of the complexes, the study of synthetic tuning of the HOMO/LUMO energies of the complexes through introduction of electron-withdrawing substituent(s) on the ligand and/or that of heteroaromatic ring(s). By introducing another interaction site into Ir complexes, it is considered that a more sensitive HOMO/LUMO energies change occurs. Therefore, we focused on the arylborane compounds. When boron has a tri-substituted structure, it has an vacant p-orbital and has a planar structure. Since this vacant p-orbital shows Lewis acidity, it is considered that it acts as an acceptor site. Furthermore, the excited-states of arylborane derivatives are expected to be utilized to photoinduced electron transfer systems. Therefore, in this study, we synthesized a novel iridium(III) complexes having various boron substituents, which is thought to cause intramolecular charge transfer, and investigated its spectroscopic properties. Figure 1

(Invited) Hole-Transporting Materials for Perovskite Solar Cells: A Theoretical Insight

Hole-transporting materials (HTMs) are a crucial component in obtaining high power conversion efficiencies (PCEs) in perovskite-based solar cells (PSCs). They play the important roles of extracting the photogenerated holes, formed within the perovskite film, and transporting them to the electrodes. Among the wide number of chemical structures proposed as HTMs for PSCs, small organic molecules have received special attention with spiro-OMeTAD (2,2´,7,7´-tetrakis(N,N-di-p-methoxyphenylamine)-9,9´-spirobifluorene) as a reference.1 In this communication, we first focus on how the donor ability and hole reorganization energy change with the chemical structure of the HTM. Sulfur-rich compounds, such as the anthracene-tetrathiophene ATT-OMe system displayed in Figure 1a, that have been used as HTMs in PSCs achieving remarkable PCEs, are theoretically described.2 Second, we investigate a series of HTMs based on fused polyheteroaromatic molecules incorporating 7-azaindole terminal moieties bearing hydrogen-bond donor and hydrogen-bond acceptor sites (Figure 1b). The 7-azaindole units induce the hydrogen-bond self-assembly of the conjugated molecules thus increasing the supramolecular ordering in the HTM layer. The effects of this ordering on the charrier transport in the HTM semiconducting layer are theoretically discussed.3 Third, we briefly present how the optical properties (energy bandgap) of Cs2AgBiBr6 lead-free double perovskites can be tuned by substituting the monovalent Ag1+ and trivalent Bi3+ cations by divalent Sn2+, Ge2+ and Zn2+ cations.4 Figure 1. Chemical structure of the sulfur-rich ATT-OMe (a) and the H-bond-promoting ADAI (b) HTM molecules. Both HTMs are based on an anthracene central core. References J. Urieta, I. García-Benito, A. Molina-Ontoria, N. Martín, Chem. Soc. Rev. 2016, 47, 8541.I. Zimmermann, J. Urieta-Mora, P. Gratia, J. Aragó, G. Grancini, A. Molina-Ontoria, E. Ortí, N. Martín, M. K. Nazeeruddin, ACS Appl. Mater. Interfac. 2017, 7, 1601674.P. Gómez, S. Georgakopoulos, M. Más-Montoya, J. Cerdá, J. Pérez, E. Ortí, J. Aragó, D. Curiel, J. Mater. Chem. C 2021, 13, 8620.P. Sebastiá-Luna, J. Calbo, N. Albiach-Sebastián, M. Sessolo, F. Palazón, E. Ortí, H. J. Bolink, Chem. Mater. 2021, 33, 8028. Figure 1

Large enhancement of visible light photocatalytic efficiency of ZnO films doped in-situ by copper during atomic layer deposition growth

In the present study, we investigate the photocatalytic activity of ZnO thin films doped by copper atoms in successive steps during the film growth by the atomic layer deposition method. Scanning electron microscopy and x-ray diffraction measurements reveal a polycrystalline structure of samples with degrading crystallinity for films with higher Cu content. X-ray photoelectron spectroscopy analysis is consistent with the presence of copper in the Cu+ state for samples with a relative Cu content lower than 1 at.%. Those samples exhibit p-type conductivity indicating that copper ions occupy substitutional, CuZn, acceptor sites in ZnO. As established from UV–vis measurements, Cu-doped ZnO films also show enhanced optical absorption in the visible region. A reduced electron-hole recombination rate, due to much lower intrinsic free charge carrier concentrations in the doped samples, and the increased light absorption in the visible region, lead to a large enhancement of photocatalytic efficiency observed in doped films under simulated sunlight irradiation.

CRISPR/Cas9-based double-strand oligonucleotide insertion strategy corrects metabolic abnormalities in murine glycogen storage disease type-Ia.

Glycogen storage disease type-Ia (GSD-Ia), characterized by impaired blood glucose homeostasis, is caused by a deficiency in glucose-6-phosphatase-α (G6Pase-α or G6PC). Using the G6pc-R83C mouse model of GSD-Ia, we explored a CRISPR/Cas9-based double-strand DNA oligonucleotide (dsODN) insertional strategy that uses the nonhomologous end-joining repair mechanism to correct the pathogenic p.R83C variant in G6pc exon-2. The strategy is based on the insertion of a short dsODN into G6pc exon-2 to disrupt the native exon and to introduce an additional splice acceptor site and the correcting sequence. When transcribed and spliced, the edited gene would generate a wild-type mRNA encoding the native G6Pase-α protein. The editing reagents formulated in lipid nanoparticles (LNPs) were delivered to the liver. Mice were treated either with one dose of LNP-dsODN at age 4 weeks or with two doses of LNP-dsODN at age 2 and 4 weeks. The G6pc-R83C mice receiving successful editing expressed ~4% of normal hepatic G6Pase-α activity, maintained glucose homeostasis, lacked hypoglycemic seizures, and displayed normalized blood metabolite profile. The outcomes are consistent with preclinical studies supporting previous gene augmentation therapy which is currently in clinical trials. This editing strategy may offer the basis for a therapeutic approach with an earlier clinical intervention than gene augmentation, with the additional benefit of a potentially permanent correction of the GSD-Ia phenotype.

Allele-specific quantification of human leukocyte antigen transcript isoforms by nanopore sequencing.

While tens of thousands of HLA alleles have been identified by DNA sequencing, the contribution of alternative splicing to HLA diversity is not well characterized. In this study, we sought to determine if long-read sequencing could be used to accurately quantify allele-specific HLA transcripts in primary human lymphocytes. cDNA libraries were prepared from peripheral blood lymphocytes from 12 donors and sequenced by nanopore long-read sequencing. HLA reads were aligned to donor-specific reference sequences based on the known type of each donor. Allele-specific exon utilization was calculated as the proportion of reads aligning to each allele containing known exons, and transcript isoforms were quantified based on patterns of exon utilization within individual reads. Splice variants were rare among class I HLA genes (median exon retention rate 99%-100%), except for several HLA-C alleles with exon 5 spliced out of up to 15% of reads. Splice variants were also rare among class II HLA genes (median exon retention rate 98%-100%), except for HLA-DQB1. Consistent with previous work, exon 5 of HLA-DQB1 was spliced out in alleles with a mutated splice acceptor site at rs28688207. Surprisingly, a 28% loss of exon 5 was also observed in HLA-DQB1 alleles with an intact splice acceptor site at rs28688207. We describe a simple bioinformatic workflow to quantify allele-specific expression of HLA transcript isoforms. Further studies are warranted to characterize the repertoire of HLA transcripts expressed in different cell types and tissues across diverse populations.

Precision medicine using whole genome sequencing in a cat identifies a novel COL5A1 variant for classical Ehlers-Danlos syndrome.

Ehlers-Danlos syndromes (EDS) are a heterogeneous group of heritable connective tissue disorders occurring in both human and veterinary patients. The genetics of these disorders are poorly described in small animal patients. Define the clinical manifestations and genetic cause of a suspected form of EDS in a cat. A 14-week-old male domestic medium hair cat was presented with skin hyperextensibility and fragility. The classic tragic facial expression was observed as well as chronic pruritus and mild hyperesthesia. Blood samples and a skin biopsy sample were collected from the affected cat. Clinical examinations, histology, electron microscopy and whole genome sequencing were conducted to characterize the clinical presentation and identify possible pathogenic DNA variants to support a diagnosis. Criteria defining variant pathogenicity were examined including human disease variant databases. Histology showed sparse, disorganized collagen and an increase in cutaneous mast cells. Electron microscopy identified ultrastructural defects commonly seen in collagen type V alpha 1 chain (COL5A1) variants including flower-like collagen fibrils in cross-section. Whole genome sequencing and comparison with 413 cats in the 99 Lives Cat Genome Sequencing Consortium database identified a novel splice acceptor site variant at exon 4 in COL5A1 (c.501-2A>C). Our report broadens the current understanding of EDS in veterinary patients and supports the use of precision medicine techniques in clinical veterinary practice. The classification of variants for pathogenicity should be considered in companion animals.

Cryptic splice mutation in the fumarate hydratase gene in patients with clinical manifestations of Hereditary Leiomyomatosis and Renal Cell Cancer.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an autosomal dominant condition characterized by the development of cutaneous and uterine leiomyomas and risk for development of an aggressive form of papillary renal cell cancer. HLRCC is caused by germline inactivating pathogenic variants in the fumarate hydratase (FH) gene, which encodes the enzyme that catalyzes the interconversion of fumarate and L-malate. We utilized enzyme and protein mobility assays to evaluate the FH enzyme in a cohort of patients who showed clinical manifestations of HLRCC but were negative for known pathogenic FH gene variants. FH enzyme activity and protein levels were decreased by 50% or greater in three family members, despite normal FH mRNA expression levels as measured by quantitative PCR. Direct Nanopore RNA sequencing demonstrated 57 base pairs of retained intron sequence between exons 9 and 10 of polyadenylated FH mRNA in these patients, resulting in a truncated FH protein. Genomic sequencing revealed a heterozygous intronic alteration of the FH gene (chr1: 241498239T/C) resulting in formation of a splice acceptor site near a polypyrimidine tract, and a uterine fibroid obtained from a patient showed loss of heterozygosity at this site. The same intronic FH variant was identified in an unrelated patient who also showed a clinical phenotype of HLRCC. These data demonstrate that careful clinical assessment as well as biochemical characterization of FH enzyme activity, protein expression, direct RNA sequencing, and genomic DNA sequencing of patient-derived cells can identify pathogenic variants outside of the protein coding regions of the FH gene.

Stargardt disease-associated missense and synonymous ABCA4 variants result in aberrant splicing.

Missense variants in ABCA4 constitute approximately 50% of causal variants in Stargardt disease (STGD1). Their pathogenicity is attributed to their direct effect on protein function, whilst their potential impact on pre-mRNA splicing disruption remains poorly understood. Interestingly, synonymous ABCA4 variants have previously been classified as 'severe' variants based on in silico analyses. Here, we systemically investigated the role of synonymous and missense variants in ABCA4 splicing by combining computational predictions and experimental assays. To identify variants of interest, we used SpliceAI to ascribe defective splice predictions on a dataset of 5579 biallelic STGD1 probands. We selected those variants with predicted delta scores for acceptor/donor gain > 0.20, and no previous reports on their effect on splicing. Fifteen ABCA4 variants were selected, four of which were predicted to create a new splice acceptor site and eleven to create a new splice donor site. In addition, three variants of interest with delta scores < 0.20 were included. The variants were introduced in wild-type midigenes that contained 4 to 12kb of ABCA4 genomic sequence, which were subsequently expressed in HEK293T cells. By using RT-PCR and Sanger sequencing, we identified splice aberrations for 16 of 18 analyzed variants. SpliceAI correctly predicted the outcomes for 16 out of 18 variants, illustrating its reliability in predicting the impact of coding ABCA4 variants on splicing. Our findings highlight a causal role for coding ABCA4 variants in splicing aberrations, improving the severity assessment of missense and synonymous ABCA4 variants, and guiding to new treatment strategies for STGD1.

Hypoparathyroidism, deafness and renal dysplasia syndrome caused by a GATA3 splice site mutation leading to the activation of a cryptic splice site.

The HDR syndrome is a rare autosomal dominant disorder characterised by Hypoparathyroidism, Deafness, and Renal dysplasia, and is caused by inactivating heterozygous germline mutations in the GATA3 gene. We report an 11-year-old girl with HDR syndrome caused by a heterozygous mutation located at the splice acceptor site of exon 5 of the GATA3 gene (NM_001002295.2: c.925-1G>T). Functional studies using a minigene assay showed that this splice site mutation abolished the normal splicing of the GATA3 pre-mRNA and led to the use of a cryptic splice acceptor site, resulting in the loss of the first seven nucleotides (TCTGCAG) of exon 5 in the GATA3 mRNA. These findings increase the understanding of the mechanisms by which GATA3 splicing mutations can cause HDR syndrome.

Tuning of the Singlet-Triplet Energy Gap of Donor-Linker-Acceptor Based Thermally Activated Delayed Fluorescent Emitters.

Thermally activated delayed fluorescent emitters based on carbazole donor, benzonitrile acceptor with the linkers biphenyl, bipyridine and naphthalene are investigated using the density functional theoretical method. The molecule in which bipyridine acts as the linker with the least ΔEST is further selected for the designing of a series of D-L-A framework TADF molecules. Remarkably, the ΔEST is decreased successively by attaching the additional cyano groups at the acceptor site which is further reduced when the electron donating methoxy groups are attached at the donor site. To know the effect of substituents on ΔEST, the acceptor moiety of the D-L-A framework is modified with -F, -Cl and -CF3 substituents. The studies showed a relatively less decrement in the value of ΔEST compared to the cyano substituted molecules. However, ΔEST significantly reduced further on attaching methoxy groups at the donor site.

Whole-Exome sequencing identifies GYS2 biallelic variants in individuals with suspected epilepsy

BackgroundAdequate glucose supply is essential for brain function, therefore hypoglycemic states may lead to seizures. Since blood glucose supply for brain is buffered by liver glycogen, an impairment of liver glycogen synthesis by mutations in the liver glycogen synthase gene (GYS2) might result in a substantial neurological involvement. Here, we describe the phenotypes of affected siblings of two families harboring biallelic mutations in GYS2. MethodsTwo suspected families - a multiplex Pakistani family (family A) with three affected siblings and a family of Moroccan origin (family B) with a single affected child who presented with seizures and reduced fasting blood glucose levels were genetically characterized. Whole exome sequencing (WES) was performed on the index patients, followed by Sanger sequencing-based segregation analyses on all available members of both families. ResultsThe variant prioritization of WES and later Sanger sequencing confirmed three mutations in the GYS2 gene (12p12.1) consistent with an autosomal recessive pattern of inheritance. A homozygous splice acceptor site variant (NM_021957.3, c. 1646 -2A>G) segregated in family A. Two novel compound heterozygous variants (NM_021957.3: c.343G>A; p.Val115Met and NM_021957.3: c.875A>T; p.Glu292Val) were detected in family B, suggesting glycogen storage disorder. A special diet designed to avoid hypoglycemia, in addition to change of the anti-seizure medication led to reduction in seizure frequency. ConclusionsThis study suggests that the seizures in patients initially diagnosed with epilepsy might be directly caused, or influenced by hypoglycemia due to pathogenic variants in the GYS2 gene.

Mapping roles of active site residues in the acceptor site of the PA3944 Gcn5-related N-acetyltransferase enzyme.

An increased understanding of how the acceptor site in Gcn5-related N-acetyltransferase (GNAT) enzymes recognizes various substrates provides important clues for GNAT functional annotation and their use as chemical tools. In this study, we explored how the PA3944 enzyme from Pseudomonas aeruginosa recognizes three different acceptor substrates, including aspartame, NANMO, and polymyxin B, and identified acceptor residues that are critical for substrate specificity. To achieve this, we performed a series of molecular docking simulations and tested methods to identify acceptor substrate binding modes that are catalytically relevant. We found that traditional selection of best docking poses by lowest S scores did not reveal acceptor substrate binding modes that were generally close enough to the donor for productive acetylation. Instead, sorting poses based on distance between the acceptor amine nitrogen atom and donor carbonyl carbon atom placed these acceptor substrates near residues that contribute to substrate specificity and catalysis. To assess whether these residues are indeed contributors to substrate specificity, we mutated seven amino acid residues to alanine and determined their kinetic parameters. We identified several residues that improved the apparent affinity and catalytic efficiency of PA3944, especially for NANMO and/or polymyxin B. Additionally, one mutant (R106A) exhibited substrate inhibition toward NANMO, and we propose scenarios for the cause of this inhibition based on additional substrate docking studies with R106A. Ultimately, we propose that this residue is a key gatekeeper between the acceptor and donor sites by restricting and orienting the acceptor substrate within the acceptor site.

Modulation of n → π* Interaction in the Complexes of p-Substituted Pyridines with Aldehydes: A Theoretical Study.

n → π* interaction is analogous to the hydrogen bond in terms of the delocalization of the electron density between the two orbitals. Studies on the intermolecular complexes stabilized by the n → π* interaction are scarce in the literature. Herein, we have studied intermolecular N···C═O n → π* interactions in the complexes of p-substituted pyridines (p-R-Py) with formaldehyde (HCHO), formyl chloride (HCOCl), and acetaldehyde (CH3CHO) using quantum chemistry calculations. We have shown that the strength of the n → π* interaction can be modulated by varying the electronic substituents at the donor and acceptor sites in the complexes. Variation of the substituents at the para position of the pyridine ring from the electron-withdrawing groups (EWGs) to the electron-donating groups (EDGs) results in a systematic increase in the strength of the n → π* interaction. The strength of this interaction is also modulated by tuning the electron density toward the carbonyl bond by substituting the hydrogen atom of HCHO with the methyl and chloro groups. The modulation of this interaction due to the electronic substitutions at the n → π* donor and acceptor sites in the complexes is monitored by probing the relevant geometrical parameters, binding energies, C═O frequency redshift, NBO energies, and electron density for this interaction derived from QTAIM and NCI index analyses. Energy decomposition analysis reveals that the electrostatic interaction dominates the binding energies of these complexes, while the charge transfer interaction, which is representative of the n → π* interaction, also has a significant contribution to these.

Acceptor activation of Mg-doped GaN—Effects of N2/O2 vs N2 as ambient gas during annealing

Here, we investigate the effects of O2:N2 (1:1) as ambient gas as compared with pure N2 during activation annealing of Mg as p-type doping in GaN layers grown by MOCVD. The purpose is to understand the impact of O2 on the resulting free hole concentration and hole mobility using SIMS, XRD, STEM, AFM, and Hall effect measurements. Even though the presence of O2 in the ambient gas during annealing is very effective in reducing the H level of the Mg-doped GaN layers, the maximum achievable hole concentration and mobility is still higher with pure N2. The differences are explained by an in-diffusion of O to the GaN layer acting as n-dopant and, thus, giving rise to a compensation effect. The Mg–H complexes at substitutional (MgGa), i.e., the electrically active acceptor sites that provide free holes, are preferentially activated by annealing with N2 only as ambient gas, while annealing with O2:N2 (1:1) also dissociates electrically inactive Mg–H complexes resulting in much less residual H. At the lower growth pressure of 150 mbar compared to higher growth pressure of 300 mbar, an increasing carbon incorporation leads to a compensation effect drastically reducing the free hole concentration while the mobility is unaffected.

Homomeric chains of intermolecular bonds scaffold octahedral germanium perovskites.

Perovskites with low ionic radiimetal centres (for example, Ge perovskites) experience both geometrical constraints and a gain in electronic energy through distortion; for these reasons, synthetic attempts do not lead to octahedral [GeI6] perovskites, but rather, these crystallize into polar non-perovskite structures1-6. Here, inspired by the principles of supramolecular synthons7,8, we report the assembly of an organic scaffold within perovskite structures with the goal of influencing the geometric arrangement and electronic configuration of the crystal, resulting in the suppression of the lone pair expression of Ge and templating the symmetric octahedra. We find that, to produce extended homomeric non-covalent bonding, the organic motif needs to possess self-complementary properties implemented using distinct donor and acceptor sites. Compared with the non-perovskite structure, the resulting [GeI6]4- octahedra exhibit a direct bandgap with significant redshift (more than 0.5 eV, measured experimentally), 10times lower octahedral distortion (inferred from measured single-crystal X-ray diffraction data) and 10times higher electron and hole mobility (estimatedby density functional theory). We show that the principle of this design is not limited to two-dimensional Ge perovskites; we implement it in the case of copper perovskite (also a low-radius metal centre), and we extend it to quasi-two-dimensional systems. We report photodiodes with Ge perovskites that outperform their non-octahedral and lead analogues. The construction of secondary sublattices that interlock with an inorganic framework within a crystal offers a new synthetic tool for templating hybrid lattices with controlled distortion and orbital arrangement, overcoming limitations in conventional perovskites.

Identification and characterization of the compound heterozygous variants of TYR gene in a northern Chinese family with Oculocutaneous albinism type 1.

Oculocutaneous albinism (OCA) is a genetically heterogeneous disease and is most inherited in an autosomal recessive manner. The characteristic manifestation of OCA is due to disfunction of melanin synthesis. OCA1 is the most severe subtype of OCA and is caused by homozygous or compound heterozygous variants in tyrosinase (TYR) gene, which is the key gene for melanin synthesis. This study aimed to identify the genetic variants of a northern Chinese family with OCA1. Clinical information and peripheral blood samples were collected. PCR amplification and Sanger sequencing were used to detect the entire exons and adjacent flanking sequences of TYR gene. Functional prediction of variants was performed by various bioinformatic analyses, while the pathogenicity classification of variants was evaluated according to ACMG standards and guidelines. A missense variant NM_000372.5:c.107G > C;NP_000363.1:p.C36S was discovered in TYR gene which converted cysteine to serine. Another variant in intron, NM_000372.5:c.1037-7 T > A, also affected the function of TYR gene. We verified the pathogenicity of the intron variant with a pCAS2 mini-gene based splicing assay and found that c.1037-7 T > A led to an insertion of 5 bp upstream from the common acceptor site of exon 3, which caused a frameshift TYR:c.1037-7 T > A:p.G346Efs*11. The results showed that the compound heterozygous variants c.107G > C:p.C36S and c.1037-7 T > A:p.G346Efs*11 of TYR gene were the pathogenic variants for this OCA1 family.

Molecular characterization of multiple putative novel hepatitis B virus spliced DNA from a chronic hepatitis B patient

Spliced hepatitis B virus (HBV) RNA has been reported to affect the viral life cycle and progression of liver disease. As much as 30% of HBV RNA are spliced in infected cells, and some can be reverse transcribed to spliced DNA. To date, only a small number of spliced DNA have been identified and the majority require further investigation. This study aimed to identify the types of spliced DNA from the sera of a chronic hepatitis B patient. HBV DNA was isolated from the serum, and both full-length and spliced DNA were amplified by PCR. The amplified PCR products were then subcloned and sequenced using a Sanger sequence analysis. As a result, 19 types of spliced DNA were identified, 11 of which were assumed to be putative novel spliced DNA. These spliced DNA were doubly spliced with varied splice donor sites and splice acceptor sites. In addition to the frequently detected HBV SP1, SP2, and SP4, we also identified 11 putative novel spliced DNA in the serum. These findings indicate the complexity of HBV RNA splicing during viral life cycle.

Designing strategies towards non-fullerene DTCR1 based compounds for the exploration of non-linear optical behavior

In this work, non-fullerene based derivatives (DTCD2-DTCD8) with D1-π-D2-π-A architecture were tailored by alteration of terminal acceptor group of a reference molecule (DTCR1) in order to investigate their non-linear optical (NLO) behavior. The effect of peripheral acceptor and donor sites on designed configuration for optical communication and electronic response was examined using DFT based calculations. The natural bond orbitals (NBOs), frontier molecular orbitals (FMOs), UV–Vis analysis, nonlinear optics (NLO), density of states (DOS) and transition density matrix (TDM) were calculated at M06-2X/6-311G(d,p) level. The energy gap of DTCD2-DTCD8 was found to be lowered (ΔE = 3.970–3.603 eV) with wider absorption spectra as compared to that of DTCR1 (4.221 eV). All the derivatives (DTCD2-DTCD8) demonstrated significant NLO behavior than the reference (DTCR1). Among all the designed compounds, DTCD8 exhibited the highest dipole moment (µtotal = 4.777 D), average linear polarizability [〈α〉 = 1.920 × 10−22esu], first hyperpolarizability (βtotal = 10.58 × 10−28esu) and second hyperpolarizability (γtotal = 8.028 × 10−33esu) as it showed the lowest energy gap (3.603 eV) as compared to the other molecules.