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1.
Nature ; 623(7986): 406-414, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37914938

RESUMEN

Establishing how neural function emerges from network properties is a fundamental problem in neuroscience1. Here, to better understand the relationship between the structure and the function of a nervous system, we systematically measure signal propagation in 23,433 pairs of neurons across the head of the nematode Caenorhabditis elegans by direct optogenetic activation and simultaneous whole-brain calcium imaging. We measure the sign (excitatory or inhibitory), strength, temporal properties and causal direction of signal propagation between these neurons to create a functional atlas. We find that signal propagation differs from model predictions that are based on anatomy. Using mutants, we show that extrasynaptic signalling not visible from anatomy contributes to this difference. We identify many instances of dense-core-vesicle-dependent signalling, including on timescales of less than a second, that evoke acute calcium transients-often where no direct wired connection exists but where relevant neuropeptides and receptors are expressed. We propose that, in such cases, extrasynaptically released neuropeptides serve a similar function to that of classical neurotransmitters. Finally, our measured signal propagation atlas better predicts the neural dynamics of spontaneous activity than do models based on anatomy. We conclude that both synaptic and extrasynaptic signalling drive neural dynamics on short timescales, and that measurements of evoked signal propagation are crucial for interpreting neural function.


Asunto(s)
Caenorhabditis elegans , Vías Nerviosas , Neuronas , Animales , Caenorhabditis elegans/anatomía & histología , Caenorhabditis elegans/citología , Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiología , Calcio/análisis , Calcio/metabolismo , Modelos Neurológicos , Mutación , Vías Nerviosas/fisiología , Neuronas/metabolismo , Neuronas/fisiología , Neuropéptidos/metabolismo , Sinapsis/metabolismo , Transducción de Señal/fisiología
2.
PLoS Biol ; 21(9): e3002280, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37733772

RESUMEN

Animals must integrate sensory cues with their current behavioral context to generate a suitable response. How this integration occurs is poorly understood. Previously, we developed high-throughput methods to probe neural activity in populations of Caenorhabditis elegans and discovered that the animal's mechanosensory processing is rapidly modulated by the animal's locomotion. Specifically, we found that when the worm turns it suppresses its mechanosensory-evoked reversal response. Here, we report that C. elegans use inhibitory feedback from turning-associated neurons to provide this rapid modulation of mechanosensory processing. By performing high-throughput optogenetic perturbations triggered on behavior, we show that turning-associated neurons SAA, RIV, and/or SMB suppress mechanosensory-evoked reversals during turns. We find that activation of the gentle-touch mechanosensory neurons or of any of the interneurons AIZ, RIM, AIB, and AVE during a turn is less likely to evoke a reversal than activation during forward movement. Inhibiting neurons SAA, RIV, and SMB during a turn restores the likelihood with which mechanosensory activation evokes reversals. Separately, activation of premotor interneuron AVA evokes reversals regardless of whether the animal is turning or moving forward. We therefore propose that inhibitory signals from SAA, RIV, and/or SMB gate mechanosensory signals upstream of neuron AVA. We conclude that C. elegans rely on inhibitory feedback from the motor circuit to modulate its response to sensory stimuli on fast timescales. This need for motor signals in sensory processing may explain the ubiquity in many organisms of motor-related neural activity patterns seen across the brain, including in sensory processing areas.


Asunto(s)
Caenorhabditis elegans , Neuronas , Animales , Caenorhabditis elegans/fisiología , Retroalimentación , Neuronas/fisiología , Interneuronas/fisiología , Locomoción/fisiología
3.
Plant Physiol ; 195(3): 2213-2233, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38466200

RESUMEN

Rho of Plant (ROP) GTPases function as molecular switches that control signaling processes essential for growth, development, and defense. However, their role in specialized metabolism is poorly understood. Previously, we demonstrated that inhibition of protein geranylgeranyl transferase (PGGT-I) negatively impacts the biosynthesis of monoterpene indole alkaloids (MIA) in Madagascar periwinkle (Catharanthus roseus), indicating the involvement of prenylated proteins in signaling. Here, we show through biochemical, molecular, and in planta approaches that specific geranylgeranylated ROPs modulate C. roseus MIA biosynthesis. Among the six C. roseus ROP GTPases (CrROPs), only CrROP3 and CrROP5, having a C-terminal CSIL motif, were specifically prenylated by PGGT-I. Additionally, their transcripts showed higher expression in most parts than other CrROPs. Protein-protein interaction studies revealed that CrROP3 and CrROP5, but not ΔCrROP3, ΔCrROP5, and CrROP2 lacking the CSIL motif, interacted with CrPGGT-I. Further, CrROP3 and CrROP5 exhibited nuclear localization, whereas CrROP2 was localized to the plasma membrane. In planta functional studies revealed that silencing of CrROP3 and CrROP5 negatively affected MIA biosynthesis, while their overexpression upregulated MIA formation. In contrast, silencing and overexpression of CrROP2 had no effect on MIA biosynthesis. Moreover, overexpression of ΔCrROP3 and ΔCrROP5 mutants devoid of sequence coding for the CSIL motif failed to enhance MIA biosynthesis. These results implicate that CrROP3 and CrROP5 have a positive regulatory role on MIA biosynthesis and thus shed light on how geranylgeranylated ROP GTPases mediate the modulation of specialized metabolism in C. roseus.


Asunto(s)
Catharanthus , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas , Catharanthus/genética , Catharanthus/metabolismo , Catharanthus/enzimología , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Prenilación de Proteína , Secuencias de Aminoácidos , Alcaloides/metabolismo , Alcaloides/biosíntesis
4.
PLoS Biol ; 20(1): e3001524, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-35089912

RESUMEN

We present a high-throughput optogenetic illumination system capable of simultaneous closed-loop light delivery to specified targets in populations of moving Caenorhabditis elegans. The instrument addresses three technical challenges: It delivers targeted illumination to specified regions of the animal's body such as its head or tail; it automatically delivers stimuli triggered upon the animal's behavior; and it achieves high throughput by targeting many animals simultaneously. The instrument was used to optogenetically probe the animal's behavioral response to competing mechanosensory stimuli in the the anterior and posterior gentle touch receptor neurons. Responses to more than 43,418 stimulus events from a range of anterior-posterior intensity combinations were measured. The animal's probability of sprinting forward in response to a mechanosensory stimulus depended on both the anterior and posterior stimulation intensity, while the probability of reversing depended primarily on the anterior stimulation intensity. We also probed the animal's response to mechanosensory stimulation during the onset of turning, a relatively rare behavioral event, by delivering stimuli automatically when the animal began to turn. Using this closed-loop approach, over 9,700 stimulus events were delivered during turning onset at a rate of 9.2 events per worm hour, a greater than 25-fold increase in throughput compared to previous investigations. These measurements validate with greater statistical power previous findings that turning acts to gate mechanosensory evoked reversals. Compared to previous approaches, the current system offers targeted optogenetic stimulation to specific body regions or behaviors with many fold increases in throughput to better constrain quantitative models of sensorimotor processing.


Asunto(s)
Caenorhabditis elegans/fisiología , Ensayos Analíticos de Alto Rendimiento , Mecanotransducción Celular/fisiología , Movimiento/fisiología , Optogenética/métodos , Animales , Conducta Animal/fisiología , Retroalimentación Sensorial/fisiología , Optogenética/instrumentación , Estimulación Luminosa , Células Receptoras Sensoriales/citología , Células Receptoras Sensoriales/fisiología
5.
Mol Plant Microbe Interact ; 37(2): 93-97, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38105425

RESUMEN

Rapidly evolving bacterial pathogens pose a unique challenge for long-term plant disease management. In this study, we investigated the types and rate of mutations in bacterial populations during seasonal disease epidemics. Two phylogenetically distinct strains of the bacterial spot pathogen, Xanthomonas perforans, were marked, released in tomato fields, and recaptured at several time points during the growing season. Genomic variations in recaptured isolates were identified by comparative analysis of their whole-genome sequences. In total, 180 unique variations (116 substitutions, 57 insertions/deletions, and 7 structural variations) were identified from 300 genomes, resulting in the overall host-associated mutation rate of ∼0.3 to 0.9/genome/week. This result serves as a benchmark for bacterial mutation during epidemics in similar pathosystems. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Asunto(s)
Enfermedades de las Plantas , Xanthomonas , Estaciones del Año , Enfermedades de las Plantas/microbiología , Bacterias/genética , Genoma Bacteriano/genética , Mutación , Xanthomonas/genética
6.
Artículo en Inglés | MEDLINE | ID: mdl-38949619

RESUMEN

The emergence of plant pathogens is often associated with waves of unique evolutionary and epidemiological events. Xanthomonas hortorum pv. gardneri is one of the major pathogens causing bacterial spot disease of tomatoes. After its first report in the 1950s, there were no formal reports on this pathogen until the 1990s, despite active global research on the pathogens that cause tomato and pepper bacterial spot disease. Given the recently documented global distribution of X. hortorum pv. gardneri, our objective was to examine genomic diversification associated with its emergence. We sequenced the genomes of X. hortorum pv. gardneri strains collected in eight countries to examine global population structure and pathways of emergence using phylodynamic analysis. We found that strains isolated post-1990 group by region of collection and show minimal impact of recombination on genetic variation. A period of rapid geographic expansion in X. hortorum pv. gardneri is associated with acquisition of a large plasmid conferring copper tolerance by horizontal transfer and coincides with the burgeoning hybrid tomato seed industry through the 1980s. The ancestry of X. hortorum pv. gardneri is consistent with introduction to hybrid tomato seed production and dissemination during the rapid increase in trade of hybrid seeds.

7.
J Org Chem ; 89(8): 5229-5238, 2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38551089

RESUMEN

Mechanochemistry refers to the initiation of chemical reactions via mechanical forces such as milling, grinding, or shearing to achieve the chemical transformations. As a manifestation of mechanocatalysis, herein, an oxidant-free and solvent-free approach for the synthesis of quinazolinones (23 derivatives) and benzothiazoles (23 derivatives) has been developed through stainless-steel-driven decarboxylative acyl radical generation from α-keto acids. A library of 2-arylquinazolinones and 2-arylbenzothiazoles has been prepared in moderate to good yields at room temperature. Moreover, control experiments and XPS studies supported the reduction (by zerovalent iron) of molecular oxygen through the moderate abrasion of balls, which promoted the generation of a superoxide radical anion via a SET process.

8.
Phytopathology ; 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38648116

RESUMEN

In this review, we highlight studies where whole genome sequencing, comparative genomics and population genomics have provided unprecedented insights into past and ongoing pathogen evolution. These include new understanding of adaptive evolution of secretion systems and their effectors. We focus on Xanthomonas pathosystems that have seen intensive study and improved our understanding of pathogen emergence and evolution, particularly in the context of host specialization: citrus canker, bacterial blight of rice, and bacterial spot of tomato and pepper. Across pathosystems, pathogens appear to follow a pattern of bursts of evolution and diversification that impact host adaptation. There remains a need for studies on the mechanisms of host range evolution and genetic exchange among closely related but differentially host-specialized species, and to start moving beyond the study of specific strain and host cultivar pairwise interactions to thinking about these pathosystems in a community context.

9.
Sensors (Basel) ; 24(2)2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-38257637

RESUMEN

Shape memory alloys (SMAs) have become the most common choice for the development of mini- and micro-type soft bio-inspired robots due to their high power-to-weight ratio, ability to be installed and operated in limited space, silent and vibration-free operation, biocompatibility, and corrosion resistance properties. Moreover, SMA spring-type actuators are used for developing different continuum robots, exhibiting high degrees of freedom and flexibility. Spring- or any elastic-material-based antagonistic or biasing force is mostly preferred among all other biasing techniques to generate periodic oscillation of SMA actuator-based robotic body parts. In this model-based study, SMA-based spring-type actuators were used to develop a carangiform-type robotic fishtail. Fin size optimization for the maximization of forward thrust was performed for the developed system by varying different parameters, such as caudal fin size, current through actuators, pulse-width modulation signal (PWM), and operating depth. A caudal fin with a mixed fin pattern between the Lunate and Fork "Lunafork" and a fin area of approximately 5000 mm2 was found to be the most effective for the developed system. The maximum forward thrust developed by this fin was recorded as 40 gmf at an operation depth of 12.5 cm in a body of still water.

10.
Environ Monit Assess ; 196(5): 491, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38691183

RESUMEN

This study explores the dual applications of a greenly synthesized ZnO@CTAB nanocomposite for the efficient remediation of Rhodamine B (RhB) and lead (Pb). The synthesis method involves a sustainable approach, emphasizing environmentally friendly practices. FT-IR, XRD, FESEM, zeta potential, and particle size analyzer (PSA), BET, and UV-VIS were used to physically characterize the zinc oxide and CTAB nanocomposite (ZnO@CTAB). The size and crystalline index of ZnO@CTAB are 77.941 nm and 63.56% respectively. The Zeta potential of ZnO@CTAB is about - 22.4 mV. The pore diameter of the ZnO@CTAB was 3.216 nm, and its total surface area was 97.42 m2/g. The mechanism of adsorption was investigated through pHZPC measurements. The nanocomposite's adsorption performance was systematically investigated through batch adsorption experiments. At pH 2, adsorbent dose of 0.025 g, and temperature 50 °C, ZnO@CTAB removed the most RhB, while at pH 6, adsorbent dose of 0.11 g, and temperature 60 °C, ZnO@CTAB removed the most Pb. With an adsorption efficiency of 214.59 mg/g and 128.86 mg/g for RhB and Pb, the Langmuir isotherm model outperforms the Freundlich isotherm model in terms of adsorption. The pseudo-2nd-order model with an R2 of 0.99 for both RhB and Pb offers a more convincing explanation of adsorption than the pseudo-1st-order model. The results demonstrated rapid adsorption kinetics and high adsorption capacities for RhB and Pb. Furthermore, there was minimal deterioration and a high reusability of ZnO@CTAB till 4 cycles were observed.


Asunto(s)
Plomo , Nanocompuestos , Rodaminas , Contaminantes Químicos del Agua , Óxido de Zinc , Plomo/química , Óxido de Zinc/química , Rodaminas/química , Nanocompuestos/química , Contaminantes Químicos del Agua/química , Adsorción , Cetrimonio/química , Restauración y Remediación Ambiental/métodos , Tecnología Química Verde , Nanoestructuras/química
11.
Clin Infect Dis ; 76(11): 1911-1918, 2023 06 08.
Artículo en Inglés | MEDLINE | ID: mdl-36718646

RESUMEN

BACKGROUND: Management of suspected Clostridioides difficile infection (CDI) in the hospital setting typically results in patient isolation, laboratory testing, infection control, and presumptive treatment. We investigated whether implementation of rapid near-patient testing (NPT) reduced patient isolation time, hospital length of stay (LOS), antibiotic usage, and cost. METHODS: A 2-period pragmatic cluster randomized crossover trial was conducted. Thirty-nine wards were randomized into 2 study arms. The primary outcome measure was effect of NPT on patient isolation time using a mixed-effects generalized linear regression model. Secondary outcomes examined were hospital LOS and antibiotic therapy based on a negative binomial regression model. Natural experiment (NE), intention-to-treat (ITT), and per-protocol (PP) analyses were conducted. RESULTS: During the entire study period, a total of 656 patients received NPT for CDI and 1667 received standard-of-care testing. For the primary outcome, a significant decrease of patient isolation time with NPT was observed (NE, 9.4 hours [P < .01]; ITT, 2.3 hours [P < .05]; PP, 6.7 hours [P < .1]). A significant reduction in hospital LOS was observed with NPT for short stay (NE, 47.4% [P < .01]; ITT, 18.4% [P < .01]; PP, 34.2% [P < .01]). Each additional hour delay for a negative result increased metronidazole use (24 defined daily doses per 1000 patients; P < .05) and non-CDI-treating antibiotics by 70.13 mg (P < .01). NPT was found to save 25.48 US dollars per patient when including test cost to the laboratory and patient isolation in the hospital. CONCLUSIONS: This pragmatic cluster randomized crossover trial demonstrated that implementation of CDI NPT can contribute to significant reductions in isolation time, hospital LOS, antibiotic usage, and healthcare cost. Clinical Trials Registration. NCT03857464.


Asunto(s)
Clostridioides difficile , Infecciones por Clostridium , Humanos , Clostridioides , Estudios Cruzados , Antibacterianos/uso terapéutico , Metronidazol/uso terapéutico , Infecciones por Clostridium/diagnóstico , Infecciones por Clostridium/tratamiento farmacológico
12.
Biochem Biophys Res Commun ; 651: 47-55, 2023 04 09.
Artículo en Inglés | MEDLINE | ID: mdl-36791498

RESUMEN

Toxin proteins are secreted by most pathogens as an integral part of pathogenic mechanism(s). The toxins act by either damaging the host cell membrane (for example, pore-forming toxins and RTX toxins) or by modulation of important cellular pathways (for example, inhibition of protein translation by ribosome-inactivating proteins). The mechanism of action of these toxins provides the pathogen with strategies for adaptation in the unfavorable host environment. Though, secreted by different pathogenic species, the protein toxins seem to share common features that allow the protein to bind to specific molecules and enter the host cell. Earlier studies have suggested role of several events like horizontal gene transfer and insertion-deletion mutations in evolution of protein toxins. The present study involving 125 bacterial protein toxins secreted by 49 pathogenic bacteria focuses on the role and constraints of the bacterial genome on evolution of codon and amino acid usage in respective bacterial protein toxins. We compare the nucleotide composition, codon and dinucleotide usage trends between different classes of bacterial protein toxins and between individual toxins and the parent bacterial genome expressing the toxin(s).


Asunto(s)
Proteínas Bacterianas , Toxinas Bacterianas , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Aminoácidos/metabolismo , Toxinas Bacterianas/química , Bacterias/genética , Bacterias/metabolismo , Codón/genética
13.
IUBMB Life ; 75(2): 82-96, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36121739

RESUMEN

Ribosome-inactivating proteins (RIPs) are toxic proteins with N-glycosidase activity. RIPs exert their action by removing a specific purine from 28S rRNA, thereby, irreversibly inhibiting the process of protein synthesis. RIPs can target both prokaryotic and eukaryotic cells. In bacteria, the production of RIPs aid in the process of pathogenesis whereas, in plants, the production of these toxins has been attributed to bolster defense against insects, viral, bacterial and fungal pathogens. In recent years, RIPs have been engineered to target a particular cell type, this has fueled various experiments testing the potential role of RIPs in many biomedical applications like anti-viral and anti-tumor therapies in animals as well as anti-pest agents in engineered plants. In this review, we present a comprehensive study of various RIPs, their mode of action, their significance in various fields involving plants and animals. Their potential as treatment options for plant infections and animal diseases is also discussed.


Asunto(s)
Plantas , Proteínas Inactivadoras de Ribosomas , Animales , Proteínas Inactivadoras de Ribosomas/uso terapéutico , Plantas/metabolismo , Antivirales/metabolismo , Ribosomas/genética , Ribosomas/metabolismo , Proteínas de Plantas
14.
Chemphyschem ; 24(9): e202200803, 2023 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-36642695

RESUMEN

Four new azo-based supramolecular materials containing thiacalixarene core substituted by variable alkoxy groups (TFA1 -TFA4 ) have been designed and synthesized for the mesomorphic and photoswitching properties. The liquid crystalline behavior were accomplished by using DSC, POM, and XRD studies. All azo-based thiacalixarene based materials with short and higher chain length display columnar hexagonal mesophase with broad temperature range. The thermal behavior of all the materials was investigated by DSC and TGA study. The structural and conformational study of the lower rim functionalized materials was confirmed by using different techniques. These thiacalixarene moulded liquid crystalline compounds shows columnar self-assembly type behavior and higher thermal stability. The introduction of bi-substituted azo-ester network towards the lower rim of thiacalixarene core has impact on the electron delocalization and liquid crystalline properties. The photoswitching properties suggested cis and trans azo-isomerization under radiation of UV light and higher thermal back relaxation time. The mesogenic behaviour of compound TFA2 and TFA4 were demolished by the influence of cis and trans isomerization. The structure-property correlation is studied to understand the variation in mesogenic properties with the substitution of variable alkoxy side chain.

15.
Chemphyschem ; 24(13): e202200760, 2023 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-37032310

RESUMEN

The newly symmetrical liquid crystalline compounds (CPB1 -CPB4 ) based on calix[4]pyrrole as central rigid core are synthesized via esterification reaction. All the four functionalized compounds exhibit columnar hexagonal phase (Colh ) over a higher mesophase temperature range and further stabilized mesophase upto room temperature. The thermal behavior and optical texture are identified by using differential scanning calorimetry (DSC), Polarizing optical microscopy (POM) while the molecular organization of compound in mesogenic state by X-ray diffraction technique. The molecular system based on calix[4]pyrrole core with symmetrical nature exhibited columnar type self-assembly at room temperature. All these four supramolecules with different side spacer show higher thermal stability. Based upon the optimization, compound CPB2 has been further tested to implicate as optical window layer in thin films solar cell devices. The calix[4]pyrrole functionalized supramolecular liquid crystalline compound based thin films showed suitable transmittance, optical energy band gap together with absorbance and extinction coefficient. The linear dependence of current on the voltage demonstrated Ohmic behavior of the CPB2 films. The surface morphology to the developed samples designated nearly uniform deposition of the CPB2 thin films together with grain growth. The findings warrant suitability of the films to implicate these as an eco-friendly optical window layer in thin films based solar cells.

16.
Org Biomol Chem ; 21(23): 4723-4743, 2023 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-37231951

RESUMEN

Vinyl azides have emerged as highly versatile precursors in organic synthesis due to their rich reactivity driven by the excellent leaving-group ability of molecular nitrogen. Over the years, significant advancement has been achieved in the manipulation of vinyl azides for the construction of C-C and C-X bonds. Typical methods involve the application of transition metals and strong oxidants for the conversion of vinyl azides into useful compounds employing harsh reaction conditions coupled with intense product purification. In this regard, visible light chemistry has become one of the most exciting fields in organic synthesis for being mild, sustainable, and often orthogonal to conventional approaches. Visible light-induced reactions involving vinyl azides generate either 2H-azirines or iminyl radicals as key intermediates, which may undergo further useful transformations to form the desired cyclic or acyclic products. Herein, we provide the most significant transformations of vinyl azides as versatile synthetic precursors or transient intermediates for compounds of synthetic and biological significance under visible light photocatalysis. We have classified this review into two parts: (i) formation of an iminyl radical intermediate and (ii) formation of 2H-azirine intermediate-based reactions.

17.
Org Biomol Chem ; 21(48): 9552-9561, 2023 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-37969017

RESUMEN

Graphitic carbon nitride (g-C3N4) as a novel heterogeneous catalyst is employed for the visible light-mediated synthesis of the imidazo[1,5-a]pyridines via the oxidative amination of C-H bond at room temperature without the need for any additional solvent. Extensive characterization of the catalyst was performed using techniques such as FT-IR, PXRD, TGA, SEM and EDX analysis. The optimized conditions enabled the successful and expeditious conversion of a wide range of substrates to imidazo[1,5-a]pyridines in good yields; a notable advantage of this catalyst being recyclability, as it can be reused for up to five cycles without significant loss of activity. This feature makes it suitable for gram-scale synthesis of imidazo[1,5-a]pyridines. Additionally, this approach offers several benefits from a green chemistry perspective as affirmed by its favorable green chemistry metrics (GCM), including low process mass intensity (PMI), low E-factor, high atom economy (AE), and good reaction mass efficiency (RME) relative to existing protocols. In addition, chemical yield (CY), mass intensity (MI), mass productivity (MP) and optimum efficiency were also calculated. This environmentally friendly method offers multiple advantages and represents a significant advancement in the synthesis of imidazo[1,5-a]pyridines.

18.
Nanotechnology ; 34(48)2023 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-37619535

RESUMEN

Worldwide, dyes are significant pollutants present in water because of their huge consumption for industrial purposes. These dyes as pollutants cause serious health issues in human beings and cause the loss of aquatic biodiversity. So, remediation of pollutants like dyes from wastewater is the need of the hour. In the present study, we greenly synthesizedSpirulina-mediated titanium oxide nanoparticles (STONPs) for the adsorptive remediation of methyl orange (MO) (anionic) and malachite green (MG) (cationic) dyes. The characterization of STONPs was performed by Field emission scanning electron microscopy (FESEM) with EDX, FT-IR, XRD, Zeta Potential and particle size analyzer, Raman spectroscopy, and UV-vis. The various parameter effects like pH, nano-adsorbent dose, the concentration of dye, contact time, and temperature were also examined. Adsorption isotherms like Langmuir, Freundlich, and Temkin, and Kinetics models like Elovich Model, Pseudo 1st, intraparticle diffusion model (IPDM), Pseudo 2nd order, and the thermodynamic model were applied for a stronger interpretation. Theqmaxattained utilizing the Langmuir adsorption model was 272.4795 mg g-1and 209.6436 mg g-1for MO and MG correspondingly. The regeneration study of synthesized nanomaterials up to five cycles was also done. We found that greenly synthesized STONPs have great potential for adsorptive remediation for both MG and MO dyes.


Asunto(s)
Contaminantes Ambientales , Nanopartículas , Humanos , Colorantes , Adsorción , Espectroscopía Infrarroja por Transformada de Fourier , Cationes , Extractos Vegetales
19.
Nanotechnology ; 34(35)2023 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-37167957

RESUMEN

Bio-nanotechnology is one of the new and sound techniques that have various advantages over conventional methods of wastewater treatment. The utilization of nanomaterials like nanoparticles for wastewater treatment is emerging field of research. Both physical and chemical methods can be used for nanoparticle synthesis, but synthesis based on algae (biological method) has numerous advantages over others as it is environmentally friendly and sustainable. Top-down and bottom-up are the two approaches used for nanoparticle synthesis, generally, bio-reduction (bottom-up approach) is used to synthesize nanoparticles. Nanoparticles can be synthesized inside the cell of algae called intracellular synthesis and outside on the surface of the cell called extracellular synthesis. Temperature, pH, and reaction time are some of the factors that can influence the synthesis, size, and properties of nanoparticles. Characterization of nanoparticles is carried out with the help of the techniques like UV-visible spectroscopy (UV-vis), x-ray diffraction, Fourier transfer infrared spectroscopy, etc. Algal nanoparticles are highly efficient in the remediation of contaminants like heavy metals and dyes from wastewater. In the present review, the utilization of algal nanoparticles for wastewater treatment containing contaminants like heavy metals, and dye, and various methods of synthesis of nanoparticles from algae are discussed. Moreover, the challenges and opportunities present in this field are also highlighted. As this field is in its initial stage, therefore, a lot of research gaps are present, which can only be filled by further new research.


Asunto(s)
Nanopartículas del Metal , Metales Pesados , Nanopartículas , Nanoestructuras , Aguas Residuales , Nanopartículas/química , Nanotecnología , Nanopartículas del Metal/química
20.
J Fluoresc ; 33(1): 25-41, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36208370

RESUMEN

A novel thiadiazole functionalized schiff base chemoreceptor (E)-2,4-dichloro-6-(((5-mercapto-1,3,4-thiadiazol-2-yl)imino)methyl)phenol (SB-1) has been synthesized and characterized spectroscopically by using various techniques. Its photophysical behaviour was scanned towards a variety of metal ions in mixed aqueous media. The chemosensor (SB-1) displayed excellent selectivity towards Cu2+ ion through fluorescent diminishment (turn-off phenomenon). Colorimetric analyses showed a rapid colour change from yellow to dark red under visible light upon addition of Cu2+ ions. Interestingly, the original yellow colour reappeared back instantly after the addition of EDTA2- anions, thus confirming the reversible nature of SB-1. Competitive experiments validated no interference from the other co-existing metal ions in the recognition process of SB-1 towards Cu2+ ion. Job's plot confirmed 1:1 binding stoichiometry between SB-1 and Cu2+ ion with the binding constant value of 3.87 × 104 M- 1. The limit of detection was determined to be 1.01 × 10- 7 M suggesting good sensitivity of SB-1 towards Cu2+ ions. Furthermore, pH-dependent UV-Vis spectral behaviour of SB-1 confirmed that it could act as an effective optical pH-sensor for highly acidic environment as well. Portable nature of probe SB-1 was explored by fabricating "easy-to-use" paper test strips, which allow robust and rapid detection of Cu2+ ions. Based on the multi-responsive properties of SB-1, a 'NOR' logic gate was constructed by applying Cu2+ and EDTA2- as chemical inputs (ln1: Cu2+, ln2: EDTA2-) while emission intensity observed at 560 nm was considered as output signal (O1). DFT optimized geometries confirmed that chemosensor SB-1 exists in Azo form (Enol form) in its ground state. Molecular docking of the SB-1 and its copper complex, into the binding site of TRK protein tyrosine kinase (PDB: 1t46) was also carried out to explore their biological activity and their potential use as TRK inhibitors.

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