Transcription System Research Articles

Development of Komagataella phaffii as a cell factory for efficient de novo production of β-caryophyllene.

β-Caryophyllene is a natural bicyclic sesquiterpene found in a large number of plants around the world. It has anti-inflammatory, anticancer and analgesic biological activities associated with its important medicinal value, and has also attracted attention in the field of bioenergy with high energy density. Due to the low amount of β-caryophyllene in plants and complex purification process, microbial biosynthesis is considered as a promising alternative for the industrial development of β-caryophyllene. Komagataella phaffii has a robust transcriptional regulatory system and has many advantages in protein expression, high-density culture, making it suitable for large-scale industrial production. However, there are no systematic studies on the efficient biosynthesis of β-caryophyllene in K. phaffii. In this study, firstly, farnesyl diphosphate synthase ERG20 and β-caryophyllene synthase AaCPS were fused and expressed with different linkers. Secondly, we enhanced the mevalonate pathway and inhibited the branch pathway. At last, the copy number of ERG20-(PA)5-AaCPS were adjusted for the biosynthesis of β-caryophyllene, a highly efficient β-caryophyllene production strain AaCPS16 was constructed. AaCPS16 could produce 136.4mg/L β-caryophyllene in shake flask level, which was 37 times higher than the initial strain AaCPS1. To the best of our knowledge, this is the first report of caryophyllene biosynthesis in Komagataella phaffii. This established a good foundation for the synthesis of sesquiterpenes in K. phaffii.

Transcription regulation of African swine fever virus: dual role of M1249L

African swine fever virus (ASFV), which poses significant risks to the global economy, encodes a unique host-independent transcription system. This system comprises an eight-subunit RNA polymerase (vRNAP), temporally expressed transcription factors and transcript associated proteins, facilitating cross-species transmission via intermediate host. The protein composition of the virion and the presence of transcription factors in virus genome suggest existence of distinct transcription systems during viral infection. However, the precise mechanisms of transcription regulation remain elusive. Through analyses of dynamic transcriptome, vRNAP-associated components and cell-based assay, the critical role of M1249L in viral transcription regulation has been highlighted. Atomic-resolution structures of vRNAP-M1249L supercomplex, exhibiting a variety of conformations, have uncovered the dual functions of M1249L. During early transcription, M1249L could serve as multiple temporary transcription factors with C-terminal domain acting as a switcher for activation/inactivation, while during late transcription it aids in the packaging of the transcription machinery. The structural and functional characteristics of M1249L underscore its vital roles in ASFV transcription, packaging, and capsid assembly, presenting novel opportunities for therapeutic intervention.

Light‐Activated Gene Expression System Using a Caging‐Group‐Free Photoactivatable Dye

AbstractOptical regulation of transcription using chemical compounds is an effective strategy to manipulate gene expression spatiotemporally. Conventional caging approaches with photoremovable protecting groups may require intense UV‐light exposure and release potentially toxic byproducts. To address these problems, here we developed a light‐mediated transcriptional regulation system by combining a caging‐group‐free photoactivatable dye PaX560 and a multidrug‐binding transcriptional regulator QacR. The cationic dye generated from PaX560 through traceless photoconversion bound QacR and reduced its repressor function, resulting in transcriptional activation. Importantly, this system allowed transcriptional activation with a large dynamic range under mild visible light exposure and simultaneous detection of the state of the photoactivated effector. This module was integrated into the T7 RNA polymerase expression system to demonstrate light‐activated transcription in vitro and in living cells.

Light-Activated Gene Expression System Using a Caging-Group-Free Photoactivatable Dye.

Optical regulation of transcription using chemical compounds is an effective strategy to manipulate gene expression spatiotemporally. Conventional caging approaches with photoremovable protecting groups may require intense UV-light exposure and release potentially toxic byproducts. To address these problems, here we developed a light-mediated transcriptional regulation system by combining a caging-group-free photoactivatable dye PaX560 and a multidrug-binding transcriptional regulator QacR. The cationic dye generated from PaX560 through traceless photoconversion bound QacR and reduced its repressor function, resulting in transcriptional activation. Importantly, this system allowed transcriptional activation with a large dynamic range under mild visible light exposure and simultaneous detection of the state of the photoactivated effector. This module was integrated into the T7 RNA polymerase expression system to demonstrate light-activated transcription in vitro and in living cells.

Maleylpyruvic Acid-Inducible Gene Expression System and Its Application for the Development of Gentisic Acid Biosensors.

Gentisic acid is a secondary plant metabolite, known for its health benefits, not only widely used as a supplement but also implicated as a potential biomarker for cancer-associated metabolism alterations. To advance bioproduction and detection of this compound or its derivatives, cell-based approaches have become of interest in recent years. However, the lack of tools for high-throughput gentisic acid monitoring and compound-metabolizing organism screening limits the progress in this area. Here, we analyzed the gene cluster responsible for gentisic acid metabolism in Cupriavidus necator H16. The transcriptional regulator GtdR-based inducible gene expression system CnGtdR/PgtdA was elucidated, showing that it was activated when C. necator cells were subjected to gentisic acid. Subsequently, a 3-maleylpyruvic acid was identified as a primary inducer for this inducible system. Furthermore, genes gtdA and gtdT, encoding for gentisate 1,2-dioxygenase and MFS transporter, were shown to be essential for inducible system activation in the presence of gentisic acid with GtdA enabling conversion of this phenolic acid into the inducer. The CnGtdRAT/PgtdA-based inducible system was employed to develop a whole-cell biosensor for the intracellular and extracellular detection of gentisic acid. The potential of the 3-maleylpyruvic acid-inducible system was demonstrated by its application in metabolic pathway research, detection of highly unstable 3-maleylpyruvic acid, and development of biosensors for the intracellular or extracellular determination of gentisic acid. In addition, the utility of the biosensor was emphasized by its application for detection of gentisic acid as a potential biomarker for cancer in urine samples.

Versatile xylose and arabinose genetic switches development for yeasts

Inducible transcription systems are essential tools in genetic engineering, where tight control, strong inducibility and fast response with cost-effective inducers are highly desired. However, existing systems in yeasts are rarely used in large-scale fermentations due to either cost-prohibitive inducers or incompatible performance. Here, we developed powerful xylose and arabinose induction systems in Saccharomyces cerevisiae, utilizing eukaryotic activators XlnR and AraRA from Aspergillus species and bacterial repressors XylR and AraRR. By integrating these signals into a highly-structured synthetic promoter, we created dual-mode systems with strong outputs and minimal leakiness. These systems demonstrated over 4000- and 300-fold regulation with strong activation and rapid response. The dual-mode xylose system was fully activated by xylose-rich agricultural residues like corncob hydrolysate, outperforming existing systems in terms of leakiness, inducibility, dynamic range, induction rate, and growth impact on host. We validated their utility in metabolic engineering with high-titer linalool production and demonstrated the transferability of the XlnR-based xylose induction system to Pichia pastoris, Candida glabrata and Candida albicans. This work provides robust genetic switches for yeasts and a general strategy for integrating activation-repression signals into synthetic promoters to achieve optimal performance.

Oxidative Stress in Genetic Cataract Formation.

Cataracts are the leading cause of blindness worldwide, and age-related cataracts are the result of environmental insults that largely lead to oxidative stress imposed on a genetic background that determines susceptibility to these stresses. A comprehensive literature review was performed to identify GWAS, targeted association studies, and TWAS that identified genes associated with age-related cataract. Additional genes associated with age-related cataracts were identified through the CAT-MAP online database. Pathway analysis was performed using Qiagen Ingenuity Pathway Analysis and pathways related to oxidative stress were analyzed using the same program. A large number of genes have been identified as causes of both Mendelian and complex cataracts. Of these, 10 genes related to oxidative stress were identified, and all were associated with age-related cataracts. These genes fall into seven canonical pathways primarily related to glutathione metabolism and other pathways related to detoxifying reactive oxygen species. While a relatively small number of antioxidant related genes were identified as being associated with cataracts, they allow the identification of redox pathways important for lens metabolism and homeostasis. These are largely related to glutathione and its metabolism, other pathways for detoxification of reactive oxygen species, and the transcriptional systems that control their expression.

Electrochemiluminescence Biosensor for Ascorbic Acid Based on Target Transformation of Cell-Free RNA Transcription System and Duplex-Specific Nuclease-Assisted Recycling Amplification.

A cell-free RNA transcription system had been coupled with electrochemiluminescence (ECL) detection technology for the first time to develop an ascorbic acid (AA, acting as a model target) biosensor. The biosensor is composed of single-stranded DNA (ssDNA) sequences modified with alkynyl and azido groups, respectively, alongside an incomplete gene circuit framework. The addition of target AA and copper ions will cause the linkage of the two ssDNA sequences through a click chemistry reaction. This results in the subsequent reconstruction of a complete gene circuit. The reconstituted gene circuit, in conjunction with the T7 RNA polymerase, drives the transcription of substantial quantities of RNA. ssDNA labeled with ferrocene (Fc) (Fc-DNA) had been immobilized on a tris(2,2'-bipyridyl) ruthenium(II) chloride hexahydrate-doped SiO2 nanoparticle (Ru@SiO2 NPs) modified electrode first. The quenching effect of Fc on Ru@SiO2 causes the low ECL detected. The transcribed RNA sequence assisted double-stranded specific nuclease (DSN) to cut the ssDNA-Fc and the ECL of the system was enhanced. Optimal experimental conditions reveal that the ECL signal exhibits a linear correlation with the logarithmic concentration of AA, spanning a detection range from 100 nM to 1 mM, with a detection limit of 45 nM. This innovative methodology expands the utility of a cell-free RNA transcription system within the realm of biosensing applications.

Continuous nucleolar ribosomal RNA synthesis in differentiating lens fiber cells until abrupt nuclear degradation required for ocular lens transparency.

Cellular differentiation requires highly coordinate action of all three transcriptional systems to produce rRNAs, mRNAs, and various "short" and "long" non-coding RNAs by RNA Polymerase I, II, and III systems, respectively. The RNA Polymerase I catalyzes transcription of about 400 copies of rDNA genes generating 18S, 5.8S, and 28S rRNA molecules from the individual primary transcript. Lens fiber cell differentiation is a unique process to study transcriptional mechanisms of individual crystallin genes as their very high transcriptional outputs are directly comparable only to globin genes in erythrocytes. Importantly, both terminally differentiated lens fiber cells and mammalian erythrocytes degrade their nuclei though by different mechanisms. In lens, generation of organelle-free zone (OFZ) includes degradation of mitochondria, endoplasmic reticulum, Golgi apparatus, and nuclei; nevertheless, very little is known about their nucleoli and rRNA transcription. Here, using RNA fluorescence in situ hybridization (FISH) we evaluated nascent rRNA transcription during the entire process of lens fiber cell differentiation. The lens fiber cell nuclei undergo morphological changes prior their denucleation, including chromatin condensation; remarkably, the nascent rRNA transcription persists in all nuclei next to the OFZ. The changes in both nuclei and nucleoli shape and microarchitecture were evaluated by immunofluorescence to detect fibrillarin, nucleolin, UBF, and other nuclear proteins. These studies demonstrate for the first time that highly condensed lens fiber cell nuclei have the capacity to support rRNA transcription. Thus, "late" production of rRNA molecules and consequently the ribosomes contribute to the terminal translational mechanisms to produce maximal quantities of the crystallin proteins.

Mechanism of polyadenylation-independent RNA polymerase II termination.

The mechanisms underlying the initiation and elongation of RNA polymerase II (Pol II) transcription are well-studied, whereas termination remains poorly understood. Here we analyze the mechanism of polyadenylation-independent Pol II termination mediated by the yeast Sen1 helicase. Cryo-electron microscopy structures of two pretermination intermediates show that Sen1 binds to Pol II and uses its adenosine triphosphatase activity to pull on exiting RNA in the 5' direction. This is predicted to push Pol II forward, induce an unstable hypertranslocated state and destabilize the transcription bubble, thereby facilitating termination. This mechanism of transcription termination may be widely used because it is conceptually conserved in the bacterial transcription system.

Implementation of Real-Time Audio-to-Text Conversion and Processing for Seamless Transformation in Classroom Environment

In modern educational settings, ensuring that all students effectively comprehend lecture content is a significant challenge, particularly when language barriers and varying levels of cognitive processing ability come into play. Traditional classroom instruction often fails to accommodate the diverse needs of all learners, leading to gaps in understanding and academic performance. This research explores the implementation of a real-time audio transcription system as a solution to enhance classroom inclusivity and comprehension. By leveraging mobile technology, students can access live speech-to-text transcriptions of lectures directly on their devices. This system is designed to assist students who struggle with listening due to language differences, hearing impairments, or other cognitive challenges. The study delves into the technological framework of the transcription service, evaluating its accuracy, latency, and usability. It also considers the practical implications of integrating such technology into various classroom settings, from elementary schools to higher education institutions. Through surveys and interviews with students and teachers, the research assesses the impact of live transcription on student engagement, participation, and academic performance. Preliminary findings suggest that live audio transcription can significantly bridge the comprehension gap, offering a practical tool to foster a more inclusive and effective learning environment. Additionally, the study explores potential challenges and solutions for widespread implementation, aiming to provide a comprehensive analysis of the benefits and limitations of this innovative educational tool.

7587 The Estrogen Receptors and ARE/Nrf2 are Involved in Protecting Human Dermal Fibroblasts from Damage Caused by Mitochondrial Disfunction

Abstract Disclosure: A. Darawshe: None. A. Trachtenberg: None. Y. Sharoni: None. Skin ageing is influenced by several factors including environmental exposure and hormonal changes. Reactive oxygen species (ROS), which mediate many of the effects of these factors, can be formed by extrinsic factors, such as sun exposure, or can result from mitochondrial dysfunction as occurs during ageing. Several studies have shown the protective role of estrogens on skin health. The aim of the current study was to examine the damage to dermal fibroblasts by mitochondrially generated ROS, and to study the mechanism of the protective effects of estradiol. Rotenone, a complex I inhibitor, was used to cause mitochondrial dysfunction in human dermal fibroblasts and its effects on mitochondrial and cytosolic ROS levels, mitochondrial respiration, cell death, apoptosis, matrix metalloproteinase-1 (MMP1) and pro-collagen secretion were determined as markers of skin damage. Rotenone caused substantial reduction of respiration, followed by increased mitochondrial and cytosolic ROS which resulted in apoptotic cell death, increased MMP1 secretion and decreased collagen secretion. Pretreatment with estradiol recovered more than 50% of the respiratory activity, reduced mitochondrial and cytosolic ROS levels and MMP1 secretion and increased cell number and collagen secretion. These effects can be partially explained by a cooperative effect of estradiol and rotenone on Antioxidant Response Element (ARE/Nrf2) transcriptional activity, which leads to upregulation of antioxidant proteins such as NQO1 and Trxr1. To determine if estrogen receptors (ER) are involved in the protective effects, we used the ER inhibitor, Fulvestrant. This inhibitor, which completely inhibited ER Response Element reporter activity, partially prevented the protective effects of estradiol. The protective effects of estradiol were Similarly reduced by ML385 and Ochratoxin A, that are inhibitors of the ARE/Nrf2 transcription system. Incubating the cells with Fulvestrant and Ochratoxin A, which inhibit both pathways, completely blocked the protective effect of estradiol. These results suggest that the estrogen receptors and the ARE/Nrf2 signaling pathways are involved in the protective effects of estradiol against the damage caused by rotenone-induced mitochondria generated oxidative stress. Presentation: 6/3/2024

Targeting Hypoxia-Inducible Factor-1α in Pancreatic Cancer: siRNA Delivery Using Hyaluronic Acid-Displaying Nanoparticles

Background/Objectives: Conventional anticancer therapies often lack specificity, targeting both cancerous and normal cells, which reduces efficacy and leads to undesired off-target effects. An additional challenge is the presence of hypoxic regions in tumors, where the Hypoxia Inducible Factor (HIF) transcriptional system drives the expression of pro-survival and drug resistance genes, leading to radio- and chemo-resistance. This study aims to explore the efficacy of targeted nanoparticle (NP)-based small interfering RNA (siRNA) therapies in downregulating these genes to enhance treatment outcomes in pancreatic cancer, a tumor type characterized by high CD44 expression and hypoxia. Methods: We utilized hyaluronic acid (HA)-displaying nanoparticles composed of positively charged chitosan (CS) complexed with siRNA to target and knock down HIF-1α in pancreatic cancer cells. Two NP formulations were prepared using either low molecular weight (LMW) or high molecular weight (HMW) CS. These formulations were evaluated for their internalization by cells and their effectiveness in gene silencing, both in vitro and in vivo. Results: The study found that the molecular weight (MW) of CS influenced the interaction between HA and CD44, as well as the release of siRNA upon internalization. The LMW CS formulation shows faster uptake kinetics, while HMW CS is more effective in gene knockdown across different cell lines in vitro. In vivo, both were able to significantly knockdown HIF-1α and some of its downstream genes. Conclusions: The results suggest that HMW and LMW CS-based NPs exhibit distinct characteristics, showing that both MWs have potential for targeted pancreatic cancer therapy by influencing different aspects of delivery and gene silencing, particularly in the hypoxic tumor microenvironment.

Abstract 39: Tryptophan contributes to the sex-dependent loss of diurnal sodium excretion in BMAL1 knockout rats.

Kidney function is time-of-day-(TOD) dependent irrespective of light, sleep, activity, and meal timing. Recent discoveries reveal that diurnal (day/night) kidney function is maintained by an intrinsic molecular clock. We recently observed that loss of this transcriptional regulatory system impairs functional rhythms in electrolyte excretion in a novel rat model. When the core clock gene, brain and muscle ARNT-like protein 1 (BMAL1) is knocked out of Sprague-Dawley rats we now find that male, but not female, BMAL1 knockout (KO) rats no longer have diurnal changes in both glomerular filtration rate (GFR; Day:1.3±0.1 vs Night:1.2±0.1mL/min/100gBW;t-test p=0.919) along with sodium excretion (UNaV) (Day:819±58 vs Night:756±113 μmol/12h; t-test p=0.439) compared to littermate wildtype controls (CON; GFR Day:1.1±0.1 vs Night:1.6±0.1mL/min/100g; t-test p=0.044; UNaV Day: 849±138 vs Night:1423±102 μmol/12h; t-test p=0.003). LC/MS analysis of plasma from KO rats found that levels of tryptophan (trp) were significantly (2-way ANOVA p Interaction =0.847, p<span style="font-size:10.8333px">Genotype</span>=0.041, p TimeofDay =0.952) lower in KO males during the day (KO:77±6, CON:99±7μM; Sidak post-hoc p=0.049) but not night (KO:78±5, CON:99±12μM; Sidak post-hoc p=0.084) with no differences in plasma trp seen in KO females (Day:110±26,107±14μM vs Night:96±8,96±12μM KO and CON respectively). Trp had recently been shown to both regulate and be regulated by the circadian clock as well as increase GFR similar to other aromatic amino acids. This led us to hypothesize that TOD trp availability may underlie the changes seen in both UNaV and GFR in male KO rats. Therefore, we gave a single dose of trp (100 mg/kg,PO) at either 7pm (lights off, ZT12) or 7am (lights on, ZT0). After a 1 wk washout period, rats were dosed again in a crossover design. Male KO rats receiving trp at ZT0 had no significant change from baseline in UNaV (818±58 vs 784±61 μmol/12h) over the following 12hrs; however, a significant increase in UNaV (756±114 vs 1152±146 μmol/12h) following ZT12 dosing was observed (2-Way ANOVA p Interaction =0.038, p TrpTime =0.087, p TimeofDay =0.210; Sidak Post-Hoc: baseline vs ZT12 trp p=0.003) with no significant change seen in female KO or either male or female CON rats. Taken together these results suggest that BMAL1 is necessary for maintaining kidney physiologic rhythms in sodium excretion potentially through changes in trp availability.

ARE/Nrf2 Transcription System Involved in Carotenoid, Polyphenol, and Estradiol Protection from Rotenone-Induced Mitochondrial Oxidative Stress in Dermal Fibroblasts.

Skin aging is associated with the increased production of mitochondrial reactive oxygen species (mtROS) due to mitochondrial dysfunction, and various phytonutrients and estrogens have been shown to improve skin health. Thus, the aim of the current study was to examine damage to dermal fibroblasts by chemically induced mitochondrial dysfunction and to study the mechanism of the protective effects of carotenoids, polyphenols, and estradiol. Rotenone, a Complex I inhibitor, caused mitochondrial dysfunction in human dermal fibroblasts, substantially reducing respiration and ATP levels, followed by increased mitochondrial and cytosolic ROS, which resulted in apoptotic cell death, an increased number of senescent cells, increased matrix metalloproteinase-1 (MMP1) secretion, and decreased collagen secretion. Pre-treatment with carotenoid-rich tomato extracts, rosemary extract, and estradiol reversed these effects. These protective effects can be partially explained by a cooperative activation of antioxidant response element (ARE/Nrf2) transcriptional activity by the protective compounds and rotenone, which led to the upregulation of antioxidant proteins such as NQO1. To determine if ARE/Nrf2 activity is crucial for cell protection, we inhibited it using the Nrf2 inhibitors ML385 and ochratoxin A. This inhibition markedly reduced the protective effects of the test compounds by diminishing their effect to reduce cytosolic ROS. Our study results indicate that phytonutrients and estradiol protect skin cells from damage caused by mtROS, and thus may delay skin cell senescence and improve skin health.

Adenosine modifications impede SARS-CoV-2 RNA-dependent RNA transcription.

SARS-CoV-2, the causative virus of the COVID-19 pandemic, follows SARS and MERS as recent zoonotic coronaviruses causing severe respiratory illness and death in humans. The recurrent impact of zoonotic coronaviruses demands a better understanding of their fundamental molecular biochemistry. Nucleoside modifications, which modulate many steps of the RNA life cycle, have been found in SARS-CoV-2 RNA, although whether they confer a pro- or antiviral effect is unknown. Regardless, the viral RNA-dependent RNA polymerase will encounter these modifications as it transcribes through the viral genomic RNA. We investigated the functional consequences of nucleoside modification on the pre-steady state kinetics of SARS-CoV-2 RNA-dependent RNA transcription using an in vitro reconstituted transcription system with modified RNA templates. Our findings show that N 6-methyladenosine and 2'-O-methyladenosine modifications slow the rate of viral transcription at magnitudes specific to each modification, which has the potential to impact SARS-CoV-2 genome maintenance.

Design and construction of light-regulated gene transcription and protein translation systems in yeast P. Pastoris

IntroductionP. pastoris is a common host for effective biosynthesis of heterologous proteins as well as small molecules. Accurate regulation of gene transcription and protein synthesis is necessary to coordinate synthetic gene circuits and optimize cellular energy distribution. Traditional methanol or other inducible promoters, natural or engineered, have defects in either fermentation safety or expression capacity. The utilization of chemical inducers typically adds complexity to the product purification process, but there is no other well-controlled protein synthesis system than promoters yet. ObjectiveThe study aimed to address the aforementioned challenges by constructing light-regulated gene transcription and protein translation systems with excellent expression capacity and light sensitivity. MethodsTrans-acting factors were designed by linking the N. crassa blue-light sensor WC-1 with the activation domain of endogenous transcription factors. Light inducible or repressive promoters were then constructed through chimeric design of cis-elements (light-responsive elements, LREs) and endogenous promoters. Various configurations of trans-acting factor/LRE pairs, along with different LRE positions and copy numbers were tested for optimal promoter performance. In addition to transcription, a light-repressive translation system was constructed through the “rare codon brake” design. Rare codons were deliberately utilized to serve as brakes during protein synthesis, which were switched on and off through the light-regulated changes in the expression of the corresponding pLRE-tRNA. ResultsAs demonstrated with GFP, the light-inducible promoter 4pLRE-cPAOX1 was 70 % stronger than the constitutive promoter PGAP, with L/D ratio = 77. The light-repressive promoter PGAP-pLRE was strictly suppressed by light, with expression capacity comparable with PGAP in darkness. As for the light-repressive translation system, the “triple brake” design successfully eliminated leakage and achieved light repression on protein synthesis without any impact on mRNA expression. ConclusionThe newly designed light-regulated transcription and translation systems offer innovative tools that optimize the application of P. pastoris in biotechnology and synthetic biology.

Guide RNA structure design enables combinatorial CRISPRa programs for biosynthetic profiling

Engineering metabolism to efficiently produce chemicals from multi-step pathways requires optimizing multi-gene expression programs to achieve enzyme balance. CRISPR-Cas transcriptional control systems are emerging as important tools for programming multi-gene expression, but poor predictability of guide RNA folding can disrupt expression control. Here, we correlate efficacy of modified guide RNAs (scRNAs) for CRISPR activation (CRISPRa) in E. coli with a computational kinetic parameter describing scRNA folding rate into the active structure (rS = 0.8). This parameter also enables forward design of scRNAs, allowing us to design a system of three synthetic CRISPRa promoters that can orthogonally activate (>35-fold) expression of chosen outputs. Through combinatorial activation tuning, we profile a three-dimensional design space expressing two different biosynthetic pathways, demonstrating variable production of pteridine and human milk oligosaccharide products. This RNA design approach aids combinatorial optimization of metabolic pathways and may accelerate routine design of effective multi-gene regulation programs in bacterial hosts.

Automatic transcription system for parliamentary debates in the context of assembly of the republic of Portugal

The transcription of parliamentary proceedings is essential for democratic governance. Traditional methods are manual and time-consuming. This work introduces an Automatic Transcription System for the Assembly of the Republic of Portugal (STAAR) that uses an automatic speech recognition model and speaker diarization technologies. STAAR was developed after analyzing existing technologies and the Assembly’s specific needs, leading to an effective solution that integrates with current processes. STAAR stands out for its efficiency in transcribing debates and adapting to parliamentary language nuances. It significantly exceeded expectations by presenting a low transcription error rate, ranging from 1.7 to 11.3%, depending on the context and speech style, reducing the time required to produce the official parliamentary debates journal, and improving overall transcription efficiency. Additionally, STAAR enabled the transcription of previously undocumented parliamentary committee meetings, enhancing the documentation of parliamentary activities. This achievement marks a significant step in modernizing parliamentary processes, increasing transparency and accessibility of political information, and positions the Portuguese Parliament at the forefront of technological innovation in parliamentary debates transcription.

Analysis of the Exchange Structure in Online Tutoring by Pre-service English Teachers

Based on the national strategy of revitalizing teacher education, as an important part of talent training, pre-service teacher education plays an important role in the process of building a high-quality education system. However, affected by many factors, there are still many problems in the practice teaching of pre-service teacher education. In recent years, private tutoring by college students has developed rapidly. Similar to other practice courses for normal students, private tutoring provides pre-service teachers with the opportunity to practice teaching, reflect on learning and improve their professional competence. This emphasis on self-reflection is in line with The Exchange Structure proposed by Sinclair and Coulthard (hereinafter referred to as S&C) at the University of Birmingham in 1975, which is widely used in classroom conversation analysis. As pointed out by Atkins (2001), it is a very valuable work for teachers to apply this model to analyze classroom teaching activities, because they can better understand the courses they teach and improve classroom teaching in this way. However, the existing researches mainly focus on the traditional classroom exchange of in-service English teachers, and there are few on the classroom conversation between pre-service English teachers and students in online tutoring. Therefore, in order to truly reflect the characteristics of exchange structure of online English tutoring, this study selects a clip of the author's (pre-service English teacher) online teaching audio one year ago and transcribe it with the transcription system developed by Hutchby & Woffitt (1999). Then, the text materials are analyzed according to the original Exchange Structure (S&C, 1975), so as to provide suggestions for the professional improvement of pre-service English teachers. At the same time, the application of the Exchange Structure can be expanded to provide data for related studies, and suggestions are put forward for the improvement of the theoretical model.