Reaction Sequence Research Articles

Synthesis and physicochemical evaluation of tetrafluorinated GABA analogue

Synthesis of 2,2,3,3-tetraftluoro-γ-aminobutyric acid (tetraF-GABA) starting from commercially available 2,2,3,3-tetrafluorobutane-1,4-diol is described. The straightforward nine-step reaction sequence allowed the production of up to 20 g of the target amino acid in 41 % overall yield. Potentiometric titration revealed increased acidity of both ionizable moieties in the title compound (the pKa values were diminished by 1.6 and 4.0 units for the COOH and NH3+ groups, respectively, as compared to parent GABA). X-ray diffraction studies and DFT calculations demonstrated different preferential conformations in solid state and solution, although the fluorine gauche effect was observed in both cases.

Does time of intraoperative exposure to the aerobiome increase microbial growth on inflatable penile prostheses?

Inflatable penile prosthesis (IPP) implantation is a surgical approach for the management of erectile dysfunction (ED). A feared complication is IPP infection, and increased operative time is a risk factor for infection. Exposure of an IPP implant to ambient air in the operating room (OR aerobiome) is thought to contribute to risk of infection from increased operative time, but this is not well-supported. The objective of this study was to evaluate if exposure to the OR aerobiome increased microbial colonization of IPPs. This was an ex vivo study using an uncoated IPP, observing standard surgical sterility and OR conditions. A sterile swab was collected every 30 min for 3 h from each IPP component. Positive controls consisted of swabs exposed to unprepped scrotal skin during in-office vasectomies. All swabs underwent quantitative polymerase chain reaction (qPCR) and next generation sequencing (NGS). Bioinformatic processing was carried out and taxonomic assignment was performed. No microbial growth was detected on any component of the IPPs at any time point, while positive control swabs all detected various skin flora, including bacterial and fungal growth. These findings suggest that exposure to the OR aerobiome does not increase the risk of IPP microbial colonization, at least within a 3-hour period. Further in vivo studies are needed.

New Insights into Photo-Fenton Chemistry: The Overlooked Role of Excited IronIII Species.

Direct photoreduction of FeIII is a widely recognized route for accelerating FeIII/FeII cycle in photo-Fenton chemistry. However, most of the wavelengths covering the full spectral range are insufficient to supply enough photon energy for the direct reduction process. Herein, the hitherto neglected mechanism of FeIII reduction that the FeIII indirect reduction pathway initiated by light energy-dependent reactivity variation and reactive excited state (ES) was explored. Evolution of excited-state FeIII species (*FeIII) resulting from metal-centered charge excitation (MCCE) of FeIII is experimentally verified using pulsed laser femtosecond transient absorption spectroscopy with UV-vis detection and theoretically verified by quantum chemical calculation. Intense photoinduced intravalence charge transition was observed at λ = 380 and 466 nm, revealing quartet 4MCCE and doublet 2MCCE and their exponential processes. Light energy-dependent variation of *FeIII reactivity was kinetically certified by fitting the apparent rate constant of the radical-chain sequence of photo-Fenton reactions. Covalency is found to compensate for the intravalence charge separation following photoexcitation of the metal center in the MCCE state of Fenton photosensitizer. The *FeIII is established as a model, demonstrating the intravalence hole delocalization in the ES can be leveraged for photo-Fenton reaction or other photocatalytic schemes based on electron transfer chemistry.

Solar Light-Induced Photoelectrochemical H2 Generation Over Hierarchical TiO2 Nanotube Arrays Decorated with CdS Nanoparticles

The process of converting solar energy into chemical energy through photoelectrochemical (PEC) water splitting holds significant promise for hydrogen and oxygen gas production. In the current study, we have demonstrated the feasibility of designing a high-performance heterojunction photoanode in a scalable manner. This photoanode sensitizes visible light active CdS onto hierarchical TiO2 nanotubes (TNT), thereby enhancing H2 generation. To achieve this, we initially employed an electrochemical anodization technique to fabricate vertically aligned self-organized TNT on a titanium (Ti) substrate. Subsequently, we designed a hierarchical structure for TNT by uniformly decorating them with TiO2 nanoparticles (NPs), thus amplifying the available surface area. By employing the sequential ionic layer adsorption and reaction (SILAR) technique, we establish visible light sensitization. The resulting decorated hierarchical TNT photoanode demonstrates an enhanced photocurrent of 2.60 mA cm−2 under AM 1.5 G simulated solar light, surpassing the performance of hierarchical TNT, and most importantly classic CdS/TNT structures by 17-fold, and 1.6-fold, respectively. Moreover, the developed photoanodes achieved photoconversion efficiency with an applied bias (ABPE) of 2.48%. Thus, this work shows that a hierarchical scaffold can be exploited to achieve enhanced activity in photoelectrochemical H2 generation.

A Novel Treponema pallidum Subspecies pallidum Strain Associated With a Painful Oral Lesion Is a Member of a Potentially Emerging Nichols-Related Subgroup.

Early syphilitic lesions are typically painless; however, several recent case studies have included patients with tender lesions and no evidence of concurrent infections. Here we present the manifestations and serological and molecular findings of a patient from New York State with a painful tongue lesion. The diagnosis of syphilis was based on a combination of physical examination, serologic, pathologic, and immunohistochemical findings. DNA obtained from a formalin-fixed, paraffin-embedded biopsy was used to characterize the infecting pathogen using polymerase chain reaction, multilocus sequence typing, and whole-genome sequencing methods. Polymerase chain reaction and multilocus sequence typing of the biopsy specimen confirmed infection with T. pallidum subspecies pallidum ( T. pallidum ) of the Nichols cluster. Whole-genome sequencing analysis of this strain (herein called NYMC01) showed that it contained 17 unique single nucleotide variations and 4 more complex genetic differences; this novel genotype matched only 2 specimens, both from a patient in Seattle, Washington. The presence of this rare genotype in 2 geographically distinct locations suggests the potential emergence and spread of a new subgroup of the Nichols cluster. To our knowledge, this is the first genomic sequence obtained from a T. pallidum strain linked to a painful lesion, and the third description of whole-genome sequencing of T. pallidum from formalin-fixed, paraffin-embedded tissue. Analysis of additional specimens may reveal that the NYMC01-related genotype represents an emerging T. pallidum subgroup and may also aid in determining whether the painful clinical presentation of primary syphilis is related to specific T. pallidum genotypes.

Merging σ-Bond Metathesis with Polymerization Catalysis: Insights into Rare-Earth Metal Complexes, End-Group Functionalization, and Application Prospects.

Polymers with well-defined structures, synthesized through metal-catalyzed processes, and having end groups exhibiting different polarity and reactivity than the backbone, are gaining considerable attention in both scientific and industrial communities. These polymers show potential applications as fundamental building blocks and additives in the creation of innovative functional materials. Investigations are directed toward identifying the most optimal and uncomplicated synthetic approach by employing a combination of living coordination polymerization mediated by rare-earth metal complexes and C-H bond activation reaction by σ-bond metathesis. This combination directly yields catalysts with diverse functional groups from a single precursor, enabling the production of terminal-functionalized polymers without the need for sequential reactions, such as termination reactions. The utilization of this innovative methodology allows for precise control over end-group functionalities, providing a versatile approach to tailor the properties and applications of the resulting polymers. This perspective discusses the principles, challenges, and potential advancements associated with this synthetic strategy, highlighting its significance in advancing the interface of metalorganic chemistry, polymer chemistry, and materials science.

Physical limits to acceleration of enzymatic reactions inside phase-separated compartments.

We present a theoretical analysis of phase-separated compartments to facilitate enzymatic chemical reactions. While phase separation can facilitate reactions by increasing local concentration, it can also hinder the mobility of reactants. In particular, we find that the attractive interactions that concentrate reactants within the dense phase can inhibit reactions by lowering the mobility of the reactants. This mobility loss severely limits the potential to enhance reaction rates. Phase separation provides greater benefit in situations where multiple sequential reactions occur and/or high order reactions, provided the enzymes are unsaturated, transport to the condensate is not limiting, and the reactants are mobile. We show that mobility can be maintained if recruitment to the condensed phase is driven by multiple attractive moieties that can bind and release independently. However, the spacers necessary to ensure independence between stickers are prone to entangle with the dense phase scaffold. We find an optimal sticker affinity that balances the need for rapid binding/unbinding kinetics and minimal entanglement. Reaction rates can be accelerated by shrinking the size of the dense phase with a corresponding increase in the number of stickers. Our results showcase the potential capabilities of phase-separated compartments to act as biochemical reaction crucibles within living cells.

Therapeutic effect and mechanisms of traditional Chinese medicine compound (Qilong capsule) in the treatment of ischemic stroke

Background Qilong capsule (QLC) is a well-known traditional Chinese medicine compound extensively used in clinical practice. It has been approved by the China's FDA for the treatment of ischemic stroke (IS). In our clinical trial involving QLC (ClinicalTrials.gov identifier: NCT03174535), we observed the potential of QLC to improve neurological function in IS patients at the 24th week, while ensuring their safety. However, the effectiveness of QLC beyond the initial 12-week period remains uncertain, and the precise mechanisms underlying its action in IS have not been fully elucidated.Purpose In order to further explore the clinical efficacy of QLC in treating IS beyond the initial 12-week period and systematically elucidate its underlying mechanisms.Study Design This study employed an interdisciplinary integration strategy that combines post hoc analysis of clinical trials, transcriptome sequencing, integrated bioinformatics analysis, and animal experiments.Methods In this study, we conducted a post-hoc analysis with 2302 participants to evaluate the effectiveness of QLC at the 12th week. The primary outcome was the proportion of patients achieving functional independence at the 12th week, defined as a score of 0–2 on the modified Rankin Scale (mRS), which ranges from 0 (no symptoms) to 6 (death). Subsequently, we employed RNA sequencing (RNA-Seq) and quantitative reverse transcription polymerase chain reaction (RT-qPCR) techniques in the QLC trial to investigate the potential molecular mechanisms underlying the therapeutic effect of QLC in IS. Simultaneously, we utilized integrated bioinformatics analyses driven by external multi-source data and algorithms to further supplement the exploration and validation of QLC's therapeutic mechanism in treating IS. This encompassed network pharmacology analysis and analyses at the mRNA, cellular, and pathway levels focusing on core targets. Additionally, we developed a disease risk prediction model using machine learning. By identifying differentially expressed core genes (DECGs) between the normal and IS groups, we quantitatively predicted IS occurrence. Furthermore, to assess its protective effects and determine the key regulated pathway, we conducted experiments using a middle cerebral artery occlusion and reperfusion (MACO/R) rat model.Results Our findings demonstrated that the combination of QLC and conventional treatment (CT) significantly improved the proportion of patients achieving functional independence (mRS score 0–2) at the 12th week compared to CT alone (n = 2,302, 88.65 % vs 87.33 %, p = 0.3337; n = 600, 91.33 % vs 84.67 %, p = 0.0165). Transcriptome data revealed that the potential underlying mechanism of QLC for IS is related to the regulation of the NF-κB inflammatory pathway. The RT-qPCR results demonstrated that the regulatory trends of key genes, such as MD-2, were consistent with those observed in the RNA-Seq analysis. Integrated bioinformatics analysis elucidated that QLC regulates the NF-κB signaling pathway by identifying core targets, and machine learning was utilized to forecast the risk of IS onset. The MACO/R rat model experiment confirmed that QLC exerts its anti-CIRI effects by inhibiting the MD-2/TLR-4/NF-κB signaling axis.Conclusion: Our interdisciplinary integration study has demonstrated that the combination of QLC with CT exhibits significant superiority over CT alone in improving functional independence in patients at the 12th week. The potential mechanism underlying QLC's therapeutic effect in IS involves the inhibition of the MD-2/TLR4/NF-κB inflammatory signaling pathway, thereby attenuating cerebral ischemia/reperfusion inflammatory injury and facilitating neurofunctional recovery. The novelty and innovative potential of this study primarily lie in the novel finding that QLC significantly enhances the proportion of patients achieving functional independence (mRS score 0–2) at the 12th week. Furthermore, employing a "multilevel-multimethod" integrated research approach, we elucidated the potential mechanism underlying QLC's therapeutic effect in IS.

Durable and highly signal-stable pressure sensors prepared by sequential thiol-acrylate click reactions

Pressure sensors are an important part of the Internet of Things (IoT) and human–machine interaction (HMI), and their signal stability and durability are greatly affected by the interfacial interaction between the substrate and the conductive layer. Herein, a pressure sensor prepared by sequential radical-mediated thiol-acrylate click reactions is reported. In first click reaction, the porous substrate polyHIPE-SH with inherently thiols is fabricated. Those thiols give us second chance to chemically bridge carboxylic carbon nanotubes (CNT)/polyethylene glycol diacrylate (PEGDA) conductive coating to the substrate using the click reaction, with 21.5 % of the thiols on the substrate involved in the reaction. As expected, the obtained pressure-sensitive material CNT/PEGDA@polyHIPE-SH has a strong interfacial interaction between the substrate and the conductive layer, thus ensuring the good signal stability and durability. The sensor also has a sensitivity of up to −6.45 % kPa−1 and a wide response range from 0 to 400 kPa. Furthermore, the sensors are used as input devices to realize multi-mode HMI, and high-accuracy object recognition at low sensor densities via a convolutional neural network based deep learning model.

Chemoenzymatic synthesis of 7-chloro-4-Dimethylallyl-L-Tryptophan, a fragment of krisynomycin

The krisynomycins are macrocyclic depsipeptide natural products from Streptomyces that act as imipenem potentiators against methicillin-resistant Staphylococcus aureus (MRSA). The flagship molecule of this family, krisynomycin, features a unique 7-chloro-4-dimethylallyl-l-tryptophan (7-Cl-4-Pren-Trp) fragment that is both essential for biological activity and unprecedented among bacterial natural products. In silico analysis of the putative biosynthetic gene cluster revealed an aromatic prenyltransferase and a tryptophan halogenase, though the precise reaction order en route to 7-Cl-4-Pren-Trp remained ambiguous. We report herein a brief chemoenzymatic synthesis of 7-Cl-4-Pren-Trp through a prenylation-chlorination sequence, which contains the first ever C4 prenylation of tryptophan by a bacterial enzyme. Furthermore, our efforts provide tentative evidence that the same reaction sequence is operative in the biosynthesis of krisynomycin.

Midline Low-Grade Gliomas of Early Childhood: Focus on Targeted Therapies.

Midline low-grade gliomas (mLGGs) of early childhood have a poorer prognosis compared with tumors of other localizations and in older patients. LGGs are associated with aberrant activation of RAS-RAF-MEK pathway, and pharmacological inhibition of the pathway has therapeutic promise. The aim of this study was clinical and molecular characterization of infantile mLGGs, with emphasis on the efficacy of targeted kinase inhibition. This study enrolled 40 patients with mLGG age <3 years. The majority of the patients (30/40) received first-line chemotherapy (CT) as per International Society of Paediatric Oncology LGG 2004 guidelines. In all patients, molecular genetic investigation of tumor tissue by polymerase chain reaction and RNA sequencing was performed. The median follow-up was 3.5 years. First-line CT failed in 24 of 30 recipients. The identified molecular profiles included KIAA1549::BRAF fusions in 26 patients, BRAF V600E in six patients, FGFR1::TACC1 fusions in two patients, and rare fusion transcripts in four patients. At disease progression, targeted therapy (TT) was initiated in 27 patients (22 patients received trametinib) on the basis of molecular findings. TT was administered for a median of 16 months, with partial response achieved in 12 of 26 (46%) patients in which response was evaluated. Severe adverse events were detected only on trametinib monotherapy: acute damage of GI or urinary mucosa complicated by hemorrhage and development of transfusion-dependent anemia in four patients and grade 3 skin toxicity in three patients. mLGGs of early childhood are often aggressive tumors, resistant to CT, and frequently require alternative treatment. The majority of patients harbor druggable molecular targets and respond to molecular TT.

Identification of effector candidates in Bipolaris sorokiniana and their expression profile analysis during pathogen-wheat interactions

Spot blotch disease, caused by the fungal pathogen Bipolaris sorokiniana, poses a significant threat to global production particularly wheat, and barley due to substantial yield losses. Similar to many fungal pathogens, the infection of host plants heavily depends on the pathogen's ability to secrete effector proteins, which manipulate host defenses and aid disease progression. However, a critical knowledge gap exists in the comprehensive identification and characterization of effector candidates (ECs) in B. sorokiniana, requiring further research efforts. Therefore, study aimed to systematically identify and characterize ECs in B. sorokiniana by conducting pathogenicity tests to confirm disease symptoms on wheat leaves, utilizing a rigorous bioinformatics approach to predict ECs through sequence analysis and structural similarities, and validating effector expression profiles during infection using RNA sequencing (RNA-Seq) and quantitative real-time polymerase chain reaction (qRT-PCR). Pathogenicity testing confirmed the typical symptoms of spot blotch disease upon inoculation with B. sorokiniana. Through bioinformatics analysis, 81 ECs were identified, showing dynamic expression patterns during infection stages. Among these ECs, genes such as Cocsa1|129517, Cocsa1|141231, and Cocsa1|193443 stood out due to their different expression patterns and structural similarities, indicating their potential roles as effectors. This study offers new novel insights into the effector repertoire of B. sorokiniana and its implications for spot blotch disease management. The identified ECs present promising targets for further investigation to clarify their specific roles in fungal virulence and host immune modulation.

Metabolic and enzymatic engineering approach for the production of 2-phenylethanol in engineered Escherichia coli

2-Phenylethanol, known for its rose-like odor and antibacterial activity, is synthesized via exogenous phenylpyruvate by the sequential reaction of phenylpyruvate decarboxylase (PDC) and aldehyde reductase. We first targeted ARO10, a phenylpyruvate decarboxylase gene from Saccharomyces cerevisiae, and identified a suitable aldehyde reductase gene. Co-expression of ARO10 and yahK in E. coli transformants yielded 1.1 g/L of 2-phenylethanol in batch culture. We hypothesized that there might be a bottleneck in PDC activity. The computer-based enzyme evolution was utilized to enhance production. The introduction of an amino acid substitution in ARO10 (ARO10 I544W) stabilized the aromatic ring of the phenylpyruvate substrate, increasing 2-phenylethanol yield 4.1-fold compared to wild-type ARO10. Cultivation of ARO10 I544W-expressing E. coli produced 2.5 g/L of 2-phenylethanol with a yield from glucose of 0.16 g/g after 72 h. This approach represents a significant advancement, achieving the highest yield of 2-phenylethanol from glucose using microbes to date.

HiFi long-read amplicon sequencing for full-spectrum variants of human mtDNA

BackgroundMitochondrial diseases (MDs) can be caused by single nucleotide variants (SNVs) and structural variants (SVs) in the mitochondrial genome (mtDNA). Presently, identifying deletions in small to medium-sized fragments and accurately detecting low-percentage variants remains challenging due to the limitations of next-generation sequencing (NGS).MethodsIn this study, we integrated targeted long-range polymerase chain reaction (LR-PCR) and PacBio HiFi sequencing to analyze 34 participants, including 28 patients and 6 controls. Of these, 17 samples were subjected to both targeted LR-PCR and to compare the mtDNA variant detection efficacy.ResultsAmong the 28 patients tested by long-read sequencing (LRS), 2 patients were found positive for the m.3243 A > G hotspot variant, and 20 patients exhibited single or multiple deletion variants with a proportion exceeding 4%. Comparison between the results of LRS and NGS revealed that both methods exhibited similar efficacy in detecting SNVs exceeding 5%. However, LRS outperformed NGS in detecting SNVs with a ratio below 5%. As for SVs, LRS identified single or multiple deletions in 13 out of 17 cases, whereas NGS only detected single deletions in 8 cases. Furthermore, deletions identified by LRS were validated by Sanger sequencing and quantified in single muscle fibers using real-time PCR. Notably, LRS also effectively and accurately identified secondary mtDNA deletions in idiopathic inflammatory myopathies (IIMs).ConclusionsLRS outperforms NGS in detecting various types of SNVs and SVs in mtDNA, including those with low frequencies. Our research is a significant advancement in medical comprehension and will provide profound insights into genetics.

Non-invasive early detection on esophageal squamous cell carcinoma and precancerous lesions by microbial biomarkers combining epidemiological factors in China.

Microbiota may be associated with esophageal squamous cell carcinoma (ESCC) development. However, it is not known the predictive value of microbial biomarkers combining epidemiological factors for the early detection of ESCC and precancerous lesions. A total of 449 specimens (esophageal swabs and saliva) were collected from 349 participants with different esophageal statuses in China to explore and validate ESCC-associated microbial biomarkers from genes level to species level by 16S rRNA sequencing, metagenomic sequencing and real-time quantitative polymerase chain reaction. A bacterial biomarker panel including Actinomyces graevenitzii (A.g_1, A.g_2, A.g_3, A.g_4), Fusobacteria nucleatum (F.n_1, F.n_2, F.n_3), Haemophilus haemolyticus (H.h_1), Porphyromonas gingivalis (P.g_1, P.g_2, P.g_3) and Streptococcus australis (S.a_1) was explored by metagenomic sequencing to early detect the participants in Need group (low-grade intraepithelial neoplasia, high-grade intraepithelial neoplasia and ESCC) vs participants without these lesions as the Noneed group. Significant quantitative differences existed for each microbial target in which the detection efficiency rate was higher in saliva than esophageal swab. In saliva, the area under the curve (AUC) based on the microbial biomarkers (A.g_4 ∩ P.g_3 ∩ H.h_1 ∩ S.a_1 ∩ F.n_2) was 0.722 (95% CI 0.621-0.823) in the exploration cohort. Combining epidemiological factors (age, smoking, drinking, intake of high-temperature food and toothache), the AUC improved to 0.869 (95% CI 0.802-0.937) in the exploration cohort, which was validated with AUC of 0.757 (95% CI 0.663-0.852) in the validation cohort. It is feasible to combine microbial biomarkers in saliva and epidemiological factors to early detect ESCC and precancerous lesions in China.

Synthesis and evaluation of 3-hydroxyquinolin-2(1H)-one derivatives as inhibitors of tyrosinase

The tyrosinase (TYR) enzyme catalyses sequential reactions in the melanogenesis pathway: l-tyrosine is oxidised to yield L-3,4-dihydroxyphenylalanine (l-dopa), which in turn is converted to dopaquinone. These two reactions are the first two steps of melanin biosynthesis and are rate limiting. The accumulation or overproduction of melanin may cause skin hyperpigmentation and inhibitors of TYR are thus of interest to the cosmeceutical industry. Several TYR inhibitors are used to treat skin hyperpigmentation, however, some are ineffective and possess questionable safety profiles. This emphasises the need to develop novel TYR inhibitors with better safety and efficacy profiles. The small molecule, 3-hydroxycoumarin, has been reported to be a good potency TYR inhibitor (IC50 = 2.49 µM), and based on this, a series of eight structurally related 3-hydroxyquinolin-2(1H)-one derivatives were synthesised with the aim to discover novel TYR inhibitors. The results showed that four of the derivatives inhibited TYR from the champignon mushroom Agaricus bisporus (abTYR) with IC50 < 6.11 µM. The most potent inhibitor displayed an IC50 value of 2.52 μM. Under the same conditions, the reference inhibitors, thiamidol and kojic acid, inhibited abTYR with IC50 values of 0.130 and 26.4 μM, respectively. Based on the small molecular structures of the active 3-hydroxyquinolin-2(1H)-one inhibitors which are amenable to structure optimisation, it may be concluded that this class of compounds are good leads for the design of TYR inhibitors for cosmeceutical applications.

Monte Carlo simulation of UV-driven synthesis of complex organic molecules on icy grain surfaces

Complex organic molecules (COMs) have been widely observed in molecular clouds and protostellar environments. One of the formation mechanisms of COMs is radical reactions on the icy grain surface driven by UV irradiation. While many experiments have reported that various COMs (including biomolecules) can be synthesized under such ice conditions, the majority of the reaction processes are unclear. Complementary numerical simulations are necessary to unveil the synthetic process behind the formation of COMs. In this study, we develop a chemical reaction simulation using a Monte Carlo method. To explore the complex reaction network of COM synthesis, the model was designed to eliminate the need to prepare reaction pathways in advance and to keep computational costs low. This allows for broad parameter surveys and a global investigation of COM synthesis reactions. With this simulation, we investigate the chemical reactions occurring on icy dust surfaces during and after UV irradiation, assuming a protoplanetary disk environment. We aim to reveal the types of organic molecules produced in a disk and the formation mechanisms of COMs, in particular, amino acids and sugars. The Monte Carlo method we developed here produces reaction sequences by selecting a reaction from all candidate reactions at each calculation step, based on Arrhenius-type weighting. For our purpose, we significantly accelerated the calculation by adopting an approximate estimation of activation energy without expensive quantum chemical calculations. The results show that photodissociation and subsequent radical-radical reactions cause random rearrangement of the covalent bonds in the initial molecules composed of methanol, formaldehyde, ammonia, and water. Consequently, highly complex molecules such as amino acids and sugars were produced in a wide range of the initial conditions. We found that the final abundances of amino acids and sugars have extremely similar dependence on the atomic ratios of the initial molecules, which peak at $ C/H 0.1$-0.3 and $ O/H 0.3$-0.5, although the amino acids abundance is usually more than ten times higher than that of sugars. To understand this dependence, a semi-analytical formula was derived. Additionally, parameter surveys of temperature, photon energy, and other factors have suggested that the decomposition reactions of amino acids and sugars undergo a rapid transition within the threshold of a given parameter.

A complete and sustained organic/inorganic reaction mechanism of Baeyer’s test

The Baeyer’s test for unsaturation has been used in Qualitative Organic Analysis for a long time. However, if an alkaline reagent is used, compounds having an active hydrogen (carbon acids) also give a positive test with potassium permanganate, detracting the test for unsaturation. The first steps of the reaction sequence have been described but the next stages are missing. These are very important because they involve the formation mode of the observed end product, brown manganese dioxide. In this communication, a complete and sustained reaction mechanism is provided for both reaction mediums, neutral and alkaline. It is in accordance with observed experimental facts. The missing steps are a redox reaction between hypomanganate and permanganate ions, and a second cyclic intermediate now formed with manganate ion. The instability of this intermediate leads directly to manganese dioxide and alkalinization of the neutral medium, as observed experimentally.

Efficient synthesis of indole-chalcones based glycohybrids and their anticancer activity

Indole based glycosides belong to the class of pharmacologically active molecules and found in diverse natural compounds. Herein, we report the synthesis of 1,2,3-triazole bridged chirally enriched diverse indole-chalcones based glycohybrids. Three series of glycohybrids were designed and efficiently synthesized using d-glucose, d-galactose and d-mannose derived 1-azido glycosides. The reactions sequence involved were, the synthesis of indole derived chalcones which were formed via Claisen–Schmidt condensation reaction and subsequently N-propargylation which leads to the production of N-propargylated indole-chalcones. The N-propargylated indole-chalcones get transformed into 1,2,3-triazole bridged indole-chalcone based glycohybrids by reacting with 1-azido sugar glycosides under click-chemistry reaction conditions. Further, the biological activity of synthesized glycohybrids (n = 27) was assessed in-vitro against MDA-MB231, MCF-7, MDA-MB453 cancer, and MCF-10A normal cell lines. The selected compounds showed potent anti-oncogenic properties against MCF-7 and MDA-MB231 breast cancer cell line with IC50 values of 1.05 µM and 11.40 µM respectively, with very good selectivity index (SI > 161). The active compounds show better binding affinity as compared to co-crystallized inhibitor 1-(tert-butyl)-3-(p-tolyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine (PP1) with HCK (PTKs) proteins in molecular docking studies.

A solution to achieve sequencing from SARS-CoV-2 specimens with low viral loads: concatenation of reads from independent reactions

BackgroundDuring the pandemic, whole genome sequencing was critical to characterize SARS-CoV-2 for surveillance, clinical and therapeutical purposes. However, low viral loads in specimens often led to suboptimal sequencing, making lineage assignment and phylogenetic analysis difficult. We propose an alternative approach to sequencing these specimens that involves sequencing in triplicate and concatenation of the reads obtained using bioinformatics. This proposal is based on the hypothesis that the uncovered regions in each replicate differ and that concatenation would compensate for these gaps and recover a larger percentage of the sequenced genome.ResultsWhole genome sequencing was performed in triplicate on 30 samples with Ct > 32 and the benefit of replicate read concatenation was assessed. After concatenation: i) 28% of samples reached the standard quality coverage threshold (> 90% genome covered > 30x); ii) 39% of samples did not reach the coverage quality thresholds but coverage improved by more than 40%; and iii) SARS-CoV-2 lineage assignment was possible in 68.7% of samples where it had been impaired.ConclusionsConcatenation of reads from replicate sequencing reactions provides a simple way to access hidden information in the large proportion of SARS-CoV-2-positive specimens eliminated from analysis in standard sequencing schemes. This approach will enhance our potential to rule out involvement in outbreaks, to characterize reinfections and to identify lineages of concern for surveillance or therapeutical purposes.