Search

β-lactamases inactivate β-lactam antibiotics leading to drug resistance. Consequently, inhibitors of β-lactamases can combat this resistance, and the β-lactamase inhibitory protein (BLIP) is a naturally occurring inhibitor. The widespread CTX-M-14 and CTX-M-15 β-lactamases have an 83% sequence identity. In this study, we show that BLIP weakly inhibits CTX-M-14 but potently inhibits CTX-M-15. The structure of the BLIP/CTX-M-15 complex reveals that binding is associated with a conformational change of an active site loop of β-lactamase. Surprisingly, the loop structure in the complex is similar to that in a drug-resistant variant (N106S) of CTX-M-14. We hypothesized that the pre-established favorable loop conformation of the N106S mutant would facilitate binding. The N106S substitution results in a ~100- and 10-fold increase in BLIP inhibition potency for CTX-M-14 and CTX-M-15, respectively. Thus, this indicates that an active site loop in β-lactamase toggles between conformations that control antibiotic hydrolysis and inhibitor susceptibility. These findings highlight the role of accessible active site conformations in controlling enzyme activity and inhibitor susceptibility as well as the influence of mutations in selectively stabilizing discrete conformations.

Proteolysis-targeting chimeras (PROTACs) and targeted covalent inhibitors (TCIs) are currently two exciting strategies in the fields of chemical biology and drug discovery. Extensive research in these two fields has been conducted, and significant progress in these fields has resulted in many clinical candidates, some of which have been approved by FDA. Recently, a novel concept termed covalent PROTACs that combine these two strategies has emerged and gained an increasing interest in the past several years. Herein, we briefly review and highlight the mechanism and advantages of TCIs and PROTACs, respectively, and the recent development of covalent PROTACs using irreversible and reversible covalent chemistry. [ABSTRACT FROM AUTHOR]

We conducted and analyzed several internet surveys in order to understand the profile of global research integrity and ethical awareness, encompassing global population distribution. These were (1) the global distribution of Committee of Publishing Ethics (COPE) membership; (2) the global distribution of "Integrity" or "Ethics" journals; (3) the level of academic integrity awareness in European higher education institutions and (4) awareness of academic integrity in the top universities of Asia and Africa. The results of this survey series highlight seriously imbalanced awareness of research integrity and publishing ethics across the world, especially in developing areas with the highest population density. We therefore propose a new index, the "Academic Integrity Awareness Index" for future discussions across the linked spheres of publishing and research. [ABSTRACT FROM AUTHOR]

There are 5,020 scientific, technical and medical (STM) periodicals, including 548 English‐language (E‐L) journals, in China. To quickly increase the international influence of Chinese journals, government management launched significant initiatives for publishers, such as the 'Project for Enhancing International Impact of China STM Journals (PIIJ, 2013–2018)'. This paper investigates the underlying objectives and assumptions made about the value and impact of Chinese E‐L journals and the effect of PIIJ support and international publisher collaboration. The authors conclude that, while the E‐L journals are demonstrating some quantifiable improvements in internationalization, there are no equal pressures or recognition for qualitative quality measures, and this may undermine the ability of Chinese E‐L journals to build sustainable strategic plans. [ABSTRACT FROM AUTHOR]

Corydalis yanhusuo is a medicinal plant frequently used in traditional Chinese medicine, which has effective medical effects in many aspects. Real-time polymerase chain reaction (RT-PCR) has been one of the most widely used methods in biosynthesis research due to its high sensitivity and quantitative properties in gene expression analysis. To obtain accurate normalization, reference genes are often selected in advance; however, no reference genes are available in C. yanhusuo. Herein, 12 reference gene candidates, named cyclophilin 2 (CYP2), elongation factor 1-α (EF1-α), protein phosphatase 2 (PP2A), SAND protein family (SAND), polypyrimidine tract-binding protein (PTBP), TIP41-like protein (TIP41), lyceraldehyde-3-phosphate hydrogenase (GAPDH), ubiquitin-conjugating enzyme 9 (UBC9), cyclophilin 1 (CYP1), tubulin beta (TUBA), thioredoxin (YLS8), and polyubiquitin 10 (UBQ10), were selected for stability analysis. After being treated with hormone, UV, salt, metal, oxidative, drought, cold (4 °C), and hot stresses (40 °C), the qRT-PCR data of the selected genes was analyzed with NormFinder, geNorm, and BestKeeper. The result indicated that GAPDH, SNAD, and PP2A were the top three most stable reference genes under most treatments. This study selected and validated reliable reference genes in C. yanhusuo under various environmental conditions, which can provide great help for future research on gene expression normalization in C. yanhusuo. [ABSTRACT FROM AUTHOR]

Real time quantitative reverse transcription PCR (RT-qPCR) has been attracting more attention for its high sensitivity in gene expression analysis. Given the widely use of RT-qPCR in normalization, it is playing a pivotal role for seeking suitable reference genes in different species. In current work, 12 candidate reference genes including Actin 2 (ACT2), Cyclophilin 2 (CYP2), Glyceraldehyde-3-phosphate dehydrogenase C2 (GAPC2), Elongation factor 1-α (EF1-α), Nuclear cap binding protein 20 (NCBP20), Serine/threonine-protein phosphatase PP2A (PP2A), Polypyrimidine tract-binding protein 1 (PTBP1), SAND family protein (SNAD), TIP41-like protein (TIP41), Tubulin beta-6 (TUB6), Ubiquitin-conjugating enzyme 9 (UBC9) and Glyceraldehyde-3-phosphatedehydrogenase (GAPDH) were screened from the transcriptome datasets of M. charantia. Afterwards, GeNorm, NormFinder and BestKeeper algorithms were applied to assess the expression stability of these 12 genes under different abiotic stresses including drought, cold, high-salt, hormone, UV, oxidative and metal stress. The results indicated that 12 selected genes exhibited various stability across the samples under different external stress conditions, but TIP41 , PTBP1 and PP2A presented high stability among all the reference genes. To validate the suitability of the identified reference genes, the results of hormone subset were compared with RNA sequencing (RNA-seq) data, and the relative abundance of Ascorbate peroxidase 1（ APX1 ）was used to confirm the reliability of the results. This work assesses the stability of reference genes in M. charantia under different abiotic stress conditions, which will be beneficent for accurate normalization of target genes in M. charantia. Image 1 • 12 candidate reference genes were screened from the transcriptome datasets of M. charantia. • Stability of 12 candidate reference genes of Momordica charantia were assessed. • TIP41 , PTBP1 and PP2A are the most reliable reference genes for the RT-qPCR analysis. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) products are widely used in daily life, agriculture, and industry because of their convenience and economic value. However, PE is one of the polymer materials remarkably resistant to degradation. Current methods of plastic waste disposal pose a threat to the environment and produce microplastic particles (MPP), which becomes a global environmental concern because of its accumulation. In this study, a PE-degrading fungus Aspergillus flavus named PEDX3, was isolated from the gut contents of wax moth Galleria mellonella. The results indicated that high-density polyethylene (HDPE) MPP was degraded into the MPP with a lower molecular weight by strain PEDX3 after 28 days incubation. In addition, Fourier Transform - Infrared Spectroscopy (FT-IR) results showed the appearance of carbonyl groups and ether groups of MPP, which also validated the degradation of PE. Furthermore, the potential degradation enzymes were investigated by Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Finally, two laccase-like multicopper oxidases (LMCOs) genes, AFLA_006190 and AFLA_053930, displayed up-regulated expression during the degradation process, which may be the candidate PE-degrading enzymes. These results have demonstrated that the A. flavus strain PEDX3 has an ability to degrade microplastic particles and the two PE-degrading enzymes provide a promising application for the PE MPP remediation. Unlabelled Image • Aspergillus flavus was isolated from the guts of wax moth Galleria mellonella. • The HT-GPC and FTIR results showed the biodegradation of polyethylene microplastics. • Two laccase-like multicopper oxidases (LMCOs) displayed up-regulated trends. • The results highlight the potential of LMCOs as tools for microplastic remediation. [ABSTRACT FROM AUTHOR]

Building on our previous work on ibrutinib-based reversible covalent Bruton's tyrosine kinase (BTK) PROTACs, we explored a different irreversible BTK inhibitor poseltinib as the BTK binder for PROTAC development. Different from ibrutinib, converting the irreversible cysteine reacting acrylamide group of poseltinib to a reversible covalent cyano-acrylamide group dramatically decreases the binding affinity to BTK by over 700 folds. Interestingly, one of the reversible covalent BTK PROTACs based on poseltinib with a rigid linker, dubbed as PS-RC-1, is highly potent (IC 50 = ~10 nM) in Mino cells but not in other mantle cell lymphoma (MCL) cell lines, such as Jeko-1 and Rec-R cells. We showed that PS-RC-1 potently induces degradation of IKZF1 and IKZF3 but not BTK or GSPT1, accounting for its toxicity in Mino cells. We further decreased the molecular size of PS-RC-1 by shrinking the BTK binding moiety and developed PS-2 as a potent BTK and IKZF1/3 triple degrader with high specificity., Competing Interests: Declaration of competing interest J.W. is the co-founder of CoActigon Inc. and Chemical Biology Probes LLC.