RESUMO
D-tagatose is a valuable rare sugar with potential health benefits such as antiobesity, low-calorie, prebiotic, and anticancer. However, its production is mainly depending on chemical or enzymatic catalysis. Herein, a cobalt-based metal-organic framework (MOF) was developed at room temperature in an aqueous system using a self-assembly method. The L-arabinose isomerase (L-AI) was immobilized into this unique MOF by an in situ encapsulation process. The morphology and structural aspects of the MOF preparations were characterized by different analytical techniques such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), confocal laser scanning microscopy (CLSM), Fourier transform infrared spectroscopy (FT-IR), and X-Ray diffraction (XRD). Moreover, thermogravimetric analysis (TGA) suggested the high thermal stability of the L-AI@MOF. Significantly, the immobilized catalyst exhibited enhanced catalytic efficiency (kcat/Km) of 3.22 mM-1 s-1 and improved turnover number (kcat) of 57.32 s-1. The L-AI@MOF efficiently catalyzes the synthesis of D-tagatose from D-galactose up to the equilibrium level (~ 50%) of isomerization in heterogeneous catalysis. Interestingly, L-AI@MOF was found stable and reusable for more than five cycles without the requirement of additional metal ions during catalysis. Thus, L-AI stabilized in the MOF system demonstrated a higher catalytic activity and potential guidance for the sustainable synthesis of rare sugar D-tagatose.
RESUMO
Bacterial infection is a major crisis of 21st era and the emergence of multidrug resistant (MDR) pathogens cause significant health problems. We developed, green chemistry-based silver nanoparticles (G-Ag NPs) using Citrus pseudolimon fruit peel extract. G-Ag NPs has a spherical shape in the range of ~ 40 nm with a surface charge of - 31 Mv. This nano-bioagent is an eco-friendly tool to combat menace of MDR. Biochemical tests prove that G-Ag NPs are compatible with human red blood cells and peripheral blood mononuclear cells. There have been many reports on the synthesis of silver nanoparticles, but this study suggests a green technique for making non-cytotoxic, non-hemolytic organometallic silver nanoparticles with a high therapeutic index for possible use in the medical field. On the same line, G-Ag NPs are very effective against Mycobacterium sp. and MDR strains including Escherichia coli, Klebsiella species, Pseudomonas aeruginosa, and Acinetobacter baumannii isolated from patient samples. Based on it, we filed a patent to Indian Patent Office (reference no. 202111048797) which can revolutionize the prevention of biomedical device borne infections in hospital pre/post-operated cases. This work could be further explored in future by in vivo experimentation with mice model to direct its possible clinical utility. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-023-01061-0.
RESUMO
In this work, CQDs decorated MnIn2S4/CdS/Bi2S3 heterojunction was prepared successfully by hydrothermal technique for photocatalytic disinfection of Escherichia coli (E. coli) and mineralization of methyl orange (MO) dye. The charge transferal route and mineralization process in CQDs-MnIn2S4/CdS/Bi2S3 heterojunction were comprehensively investigated by advanced spectroscopic techniques. The improved visible-light activity and enhanced photo-generated charge transferal efficacy caused dual Z-scheme CQDs-MnIn2S4/CdS/Bi2S3 heterojunction to achieve boosted photodegradation ability. The catalytic degradation trend was followed as CQDs-MnIn2S4/CdS/Bi2S3 > MnIn2S4 > CdS > Bi2S3. The dye was mineralized within 180 min under visible light irradiation. The effect of reaction parameters, pH effect, catalyst dosage, and H2O2 addition on MO degradation was also investigated. The degradation rate was maximal at pH 4 with a pseudo-first-order rate constant, 0.0438 min-1. The assessment of antibacterial properties revealed that CQDs-MnIn2S4/CdS/Bi2S3 composite effectively inactivated E. coli under visible light. Scavenging experiments, transient photocurrent response, and electron spin resonance spectroscopy suggested that â¢[Formula: see text] and holes were the dominant reactive species. The Z-scheme heterojunction is recyclable up to ten photocatalytic cycles according to recycling experiments. This research indicates the importance of dual Z-scheme CQDs decorated MnIn2S4/CdS/Bi2S3 heterojunction in wastewater remediation.
Assuntos
Carbono , Pontos Quânticos , Pontos Quânticos/química , Escherichia coli , Peróxido de Hidrogênio , Antibacterianos/química , LuzRESUMO
Gram-positive, aerobic, motile, rod-shaped, mesophilic epiphytic bacterium Planomicrobium okeanokoites was isolated from the surface of endemic species Himantothallus grandifolius in Larsemann Hills, Eastern Antarctica. The diversity of epiphytic bacterial communities living on marine algae remains primarily unexplored; virtually no reports from Antarctic seaweeds. The present study used morpho-molecular approaches for the macroalgae and epiphytic bacterium characterization. Phylogenetic analysis was performed using mitochondrial genome encoded COX1 gene; chloroplast genome encodes rbcL; nuclear genome encoded large subunit ribosomal RNA gene (LSU rRNA) for Himantothallus grandifolius and ribosomal encoded 16S rRNA for Planomicrobium okeanokoites. Morphological and molecular data revealed that the isolate is identified as Himantothallus grandifolius, which belongs to Family Desmarestiaceae of Order Desmarestiales in Class Phaeophyceae showing 99.8% similarity to the sequences of Himantothallus grandifolius, from King George Island, Antarctica (HE866853). The isolated bacterial strain was identified on the basis of chemotaxonomic, morpho-phylogenetic, and biochemical assays. A phylogenetic study based on 16S rRNA gene sequences revealed that the epiphytic bacterial strain SLA-357 was closest related to the Planomicrobium okeanokoites showing 98.7% sequence similarity. The study revealed the first report of this species from the Southern Hemisphere to date. Also, there has been no report regarding the association between the Planomicrobium okeanokoites and Himantothallus grandifolius; however, there are some reports on this bacterium isolated from sediments, soils, and lakes from Northern Hemisphere. This study may open a gateway for further research to know about the mode of interactions and how they affect the physiology and metabolism of each other.
Assuntos
Phaeophyceae , Planococáceas , Alga Marinha , RNA Ribossômico 16S/genética , Filogenia , Planococáceas/genética , Phaeophyceae/genética , Bactérias/genética , Alga Marinha/microbiologia , Regiões Antárticas , DNA Bacteriano/genética , Ácidos Graxos/análise , Análise de Sequência de DNA , Técnicas de Tipagem BacterianaRESUMO
Background: As per WHO, global burden of healthcare-associated infections (HAIs) ranges between 7% and 12%. There is a dire need to screen Device associated nosocomial infections (DANIs) in hospitals(1). To investigate the prevalence of microbes in hospitals in DANI cases and analyse in vitro control of multi-drug resistant strains by nanotechnology intervention. Methods: Patients diagnosed with DANI were enrolled and monitored. Identification and antibiotic susceptibility pattern of the etiological agent of DANIs were made by the phenotypic method and Vitek 2 automated systems according to standard protocol. In addition, biosynthesized nanocomposite was analysed for their antimicrobial activity by agar well-diffusion method, CFU count and DNA degradation analysis. Results: There were a total of 324 patients diagnosed with DANIs. Total 369 microbial pathogens were isolated from DANI patients. The majority (87%) of the pathogenic microbes were gram-negative bacilli and all were multidrug-resistant. 41.5% of the gram-negative isolates were ESBL producers. Methicillin-resistant Staphylococcus aureus contributes about 7.3% of the total isolates in gram-positive bacteria. Nanocomposite showed 100% bactericidal activity at 5 mg/ml concentration within 3 h of incubation, whereas 2.5 mg/ml concentration of nanocomposites takes 6 h to inhibit complete growth. Conclusions: DANI, which was found in patients of all age groups, us due to multidrug-resistant gram-negative bacteria. The most commn causative agents were Acinetobacter baumannii and Citrobacter species. Nanocomposites can provide an alternative solution to prevent the DANIs.
RESUMO
Plastic pollution has become a serious transboundary challenge to nature and human health, with estimation of reports published - predicting a twofold increase in plastic waste by 2030. However, due to the COVID-19 pandemic, the excessive use of single-use plastics (including face masks, gloves and personal protective equipment) would possibly exacerbate such forecasts. The transition towards eco-friendly alternatives like bio-based plastics and new emerging sustainable technologies would be vital to deal with future pandemics, even though the use or consumption of plastics has greatly enhanced our quality of life; it is however critical to move towards bioplastics. We cannot deny the fact that bioplastics have some challenges and shortcomings, but still, it is an ideal option for opt. The circular economy is the need of the hour for waste management. Along with all these practices, individual accountability, corporate intervention and government policy are also needed to prevent us from moving from one crisis to the next. Only through cumulative efforts, we will be able to cope up with this problem. This article collected scattered information and data about accumulation of plastic during COVID-19 worldwide. Additionally, this paper illustrates the substitution of petroleum-based plastics with bio-based plastics. Different aspects are discussed, ranging from advantages to challenges in the way of bioplastics.
Assuntos
COVID-19 , Pandemias , Humanos , Plásticos , Qualidade de Vida , SARS-CoV-2RESUMO
A solid pseudopapillary tumour of the pancreas (SPT) is a rare neoplasm accounting for less than 2% of exocrine pancreatic neoplasms. SPT occurs in adolescent young females and is mostly benign. It is a low-grade malignant tumour that may evolve years before symptoms start and has a favourable prognosis. In this report we present five cases (four females, one male, aged 16, 45, 23, 17 and 55 years, respectively) of SPT localised in the pancreas, and discuss the clinical, imaging and histologic findings with a review of the literature. We retrospectively reviewed these five patients with SPT who underwent surgical resection in our hospital with a definitive histologic diagnosis of SPT.