Coumarin-Synthetic Methodologies, Pharmacology, and Application as Natural Fluorophore.

Coumarins are secondary metabolites made up of benzene and α-pyrone rings fused together that can potentially treat various ailments, including cancer, metabolic, and degenerative disorders. Coumarins are a diverse category of both naturally occurring as well as synthesized compounds with numerous biological and therapeutic properties. Coumarins as fluorophores play a key role in fluorescent labeling of biomolecules, metal ion detection, microenvironment polarity detection, and pH detection. This review provides a detailed insight into the characteristics of coumarins as well as their biosynthesis in plants and metabolic pathways. Various synthetic strategies for coumarin core involving both conventional and green methods have been discussed comparing advantages and disadvantages of each method. Conventional methods discussed are Pechmann, Knoevenagel, Perkin, Wittig, Kostanecki, Buchwald-Hartwig, and metal-induced coupling reactions such as Heck and Suzuki, as well as green approaches involving microwave or ultrasound energy. Various pharmacological applications of coumarin derivatives are discussed in detail. The structural features and conditions responsible for influencing the fluorescence of coumarin core are also elaborated.

Recent nanotheranostic approaches in cancer research.

Humanity is suffering from cancer which has become a root cause of untimely deaths of individuals around the globe in the recent past. Nanotheranostics integrates therapeutics and diagnostics to monitor treatment response and enhance drug efficacy and safety. We hereby propose to discuss all recent cancer imaging and diagnostic tools, the mechanism of targeting tumor cells, and current nanotheranostic platforms available for cancer. This review discusses various nanotheranostic agents and novel molecular imaging tools like MRI, CT, PET, SPEC, and PAT used for cancer diagnostics. Emphasis is given to gold nanoparticles, silica, liposomes, dendrimers, and metal-based agents. We also highlight the mechanism of targeting the tumor cells, and the limitations of different nanotheranostic agents in the field of research for cancer treatment. Due to the complexity in this area, multifunctional and hybrid nanoparticles functionalized with targeted moieties or anti-cancer drugs show the best feature for theranostics that enables them to work on carrying and delivering active materials to the desired area of the requirement for early detection and diagnosis. Non-invasive imaging techniques have a specificity of receptor binding and internalization processes of the nanosystems within the cancer cells. Nanotheranostics may provide the appropriate medicine at the appropriate dose to the appropriate patient at the appropriate time.

Green and sustainable synthesis of nanomaterials: Recent advancements and limitations.

Nanomaterials have been widely used in diverse fields of research such as engineering, biomedical science, energy, and environment. At present, chemical and physical methods are the main methods for large-scale synthesis of nanomaterials, but these methods have adverse effects on the environment, and health issues, consume more energy, and are expensive. The green synthesis of nanoparticles is a promising and environmentally friendly approach to producing materials with unique properties. Natural reagents such as herbs, bacteria, fungi, and agricultural waste are used in the green synthesis of nanomaterials instead of hazardous chemicals and reduce the carbon footprint of the synthesis process. Green synthesis of nanomaterials is highly beneficial compared to traditional methods due to its low cost, negligible pollution level, and safety for the environment and human health. Nanoparticles possess enhanced thermal and electrical conductivity, catalytic activity, and biocompatibility, making them highly attractive for a range of applications, including catalysis, energy storage, optics, biological labeling, and cancer therapy. This review article provides a comprehensive overview of recent advancements in the green synthesis routes of different types of nanomaterials, including metal oxide-based, inert metal-based, carbon-based, and composite-based nanoparticles. Moreover, we discuss the various applications of nanoparticles, emphasizing their potential to revolutionize fields such as medicine, electronics energy, and the environment. The factors affecting the green synthesis of nanomaterials, and their limitations are also pointed out to decide the direction of this research field, Overall, this paper highlights the importance of green synthesis in promoting sustainable development in various industries.

Genome analysis revealed a repertoire of oligosaccharide utilizing CAZymes in Weissella confusa CCK931 and Weissella cibaria YRK005.

Weissella bacteria are gram-positive, anaerobic, fermentative, and have probiotic potential. This study aimed to compare the genomes of W. cibaria YRK005 and W. confusa CCK931 isolated from young radish and kimchi, respectively. The genomic size of W. cibaria YRK005 and W. confusa CCK931 with GC content is 2.36 Mb (45%) and 2.28 Mb (44.67%), respectively. The genome study identified 92 and 83 CAZymes genes, respectively, for W. cibaria YRK005 and W. confusa CCK931, that are responsible for 26 and 27 glycoside hydrolases (GH) and 21 and 27 glycosyl transferases. Both species have one gene for carbohydrate esterases and three genes for carbohydrate-binding modules. The primary CAZymes found in both species that are involved in oligosaccharide utilization are GH1, GH2, GH30, GH13_30, GH13_31, GH42, GH43, and GH65. The study also details the production pathways for glycogen and folate. Both strains include a unique repertoire of genes, including hypothetical proteins, showing adaptability to diverse ecological niches and evolution over time. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01232-7.

Hydrotrope assisted green synthesis of dicoumarols and in silico and in vitro antibacterial, antioxidant and xanthine oxidase inhibition studies.

Aqueous hydrotrope has been employed for the first time to synthesize heteroaryl dicoumarols by condensation of 4-hydroxycoumarin and different heterocyclic aldehydes. This method is highly efficient and green, and the same aqueous hydrotropic solution can be used up to five times without any considerable loss of yield in the product. The synthesized compounds showed good antibacterial potential against Gram-positive (Staphylococcus aureus/NTCC 0997 and B. oceanisediminis) and Gram-negative (Escherichia coli/D0157:H7 and E. coli rosetta) bacterial strains using the Resazurin microtiter plate visual method. The MIC value of 312 µg/ml for compounds 3b, 3k and 3l for S. aureus while 39 µg/ml for compounds 3a, 3b and 3k for E. coli and 625 µg/ml for 3a and 3b for B. oceanisediminis was observed. The compounds were screened via computational methods like molecular docking studies and molecular dynamic simulations with PDB Id's 2W9S and 2EX6. Antioxidant activity was assessed using DPPH and H2O2 assays. Five compounds with the best binding score in molecular docking with XO (PDB ID: 1FIQ) have been tested in an in-vitro study using an enzyme inhibition assay. Novel compound 3b gave the IC50 value of 0.28 µg/ml, comparable to the standard drug Allopurinol.Communicated by Ramaswamy H. Sarma.

Comparative genome analysis of four Leuconostoc strains with a focus on carbohydrate-active enzymes and oligosaccharide utilization pathways.

Leuconostoc is mostly found in food, plants, and dairy products. Due to their innate genomic features, such as the presence of carbohydrate-active enzymes, bacteriocins, and plasmids, Leuconostoc spp. have great biotechnological potential. In this study, four strains were isolated and identified as Leuconostoc mesenteroides SG315 (LA), L. citreum SG255 (LB), L. lactis CCK940 (LC), and L. lactis SBC001 (LD). Comparative analysis was performed using their draft genome sequences. Differences among the four strains were analyzed using the average nucleotide identity, dot plot, and multiple alignments of conserved genomic sequences. Functional profiling revealed 2134, 1917, 1751, and 1816 open reading frames; 2023, 1823, 1655, and 1699 protein-coding genes; 60, 57, 83, and 82 RNA-coding genes; and GC content of 37.5 %, 38.8 %, 43.3 %, and 43.2 %, in LA, LB, LC, and LD, respectively. The total number of genes encoding carbohydrate-active enzymes was 76 (LA), 73 (LB), 57 (LC), and 67 (LD). These results indicate that the four strains shared a large number of genes, but their gene content is different. Furthermore, most genes with unknown functions were observed in the prophage regions of the genome. This study also elucidated the oligosaccharide utilization and folate biosynthesis pathways in Leuconostoc spp. Taken together, our findings provide useful information on the genomic diversity of CAZymes in the four Leuconostoc strains and suggest that these species could be used for potent exploitation.

Neoroseomonas marina sp. nov., Isolated from a Beach Sand.

A pink-pigmented bacterium (strain JC162T = KCTC 32190T) was isolated from a beach sand sample. Cells were Gram-stain-negative, coccoid, non-motile, and strictly aerobic. EzBioCloud BLAST search of 16S rRNA gene sequence showed that strain KCTC 32190T had the highest sequence identity to the members of the genus Neoroseomonas and was closely related to N. oryzicola YC6724T (99.8%), N. sediminicola FW-3T (98.5%), N. soli 5N26T (98.2%), and other members of the genus Neoroseomonas (< 97.9%) in the family Acetobacteriaceae within the class of Alphaproteobacteria. Chemo-organoheterotrophy was the only growth mode and growth was possible on a wide range of organic substrates. Strain KCTC 32190T was positive for catalase and oxidase. Fatty acid composition of strain KCTC 32190T includes (in decreasing %) C18:1ω7c, cyclo-C19:0ω8c, C18:02-OH, C16:0, C18:03-OH, C16:1ω7c/C16:1ω6c, C16:02-OH and C16:1ω5c. Polar lipids comprised of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, an unidentified amino lipid, and three unidentified lipids. The genomic DNA G+C content of the strain KCTC 32190T was 70.9 mol%. Strain KCTC 32190T has a low ANI value of < 92.7% and genome reassociation (based on digital DNA-DNA hybridization) value of < 48.8% with the nearest type strains. The genome relatedness is supported by other polyphasic taxonomic data to propose strain KCTC 32190T as a new species in the genus Neoroseomonas with the name Neoroseomonas marina sp. nov. The type strain is strain JC162T (KCTC 32190T = CGMCC1.12364T).

Dynamics of proteo-metabolome from Rubrivivax benzoatilyticus JA2 reveals a programmed switch-off of phototrophic growth, leading to a non-cultivable state as a hyperglycemic effect.

Anoxygenic phototrophic bacteria display phenomenal metabolic plasticity leading to distinct phenotypes. Extracellular elevated glucose levels limit photosynthesis in photosynthetic organisms; diversely, cause oxidative stress with ROS generation and "diabetic" like situation in non-photosynthetic organisms. In this study, longer incubations of externally provided glucose (22 mM) inhibited photosynthetic machinery in a phototrophic bacterium, Rubrivivax benzoatilyticus. Data analysis at three time points- exponential, early and late stationary phase, uncovered dynamic protein and metabolite abundance implying metabolic rewiring led non-cultivable state in response to glucose. Protein dynamics datum suggested that proteins related to primary metabolism down-regulated prior to those of secondary metabolism. Numerous proteins for metabolism and energy generation were highly expressed during exponential phase whereas those for membrane transport/translocation and DNA repair accumulated at early and late stationary phase respectively, suggesting a programmed knock-off of phototrophic growth mode and a switch to non-cultivable state. Overall, the omics analyses explicated the metabolic adjustment associated with glucose grown cells of R. benzoatilyticus. Further, our investigation unravelled creation of oxidative stress suggesting physiological stress (oxygen limitation) might be a key player leading to a non-cultivable state in this phototrophic organism. The study, emphasizing microbial glucose intolerance, unlocks the doorway to perceive microorganisms with new perspective. SIGNIFICANCE: Anoxygenic photosynthetic bacteria (APB), thriving under diverse habitat, exhibits magnificent metabolic flexibility. Generally, phototrophy is the preferred growth mode and energy generating route for APB. But, our analyses implicated that the glucose, under phototrophic growth conditions, triggered photobleaching in an APB member, Rubrivivax benzoatilyticus. However, retention of growth along with pigmentation under chemotrophic growth mode supports that glucose gradually knocked off the phototrophic growth mode of R. benzoatilyticus and switched to an alternate energy driving route or less energy demanding non-cultivabile state. Thus, the change in lifestyle i.e. photoheterotrophic growth instead of chemotrophic perhaps, might be the prime culprit and key player in inducing the said state of non-cultivability, akin to diabetes. The study, shedding light on the plausible regulation of cultivability, unveils the programmed regulated switching between different growth modes of the organism and illuminates the importance of glucose intolerance by microorganisms. Through this investigation, we appeal that the studies on 'glucose intolerance in microorganisms' also need due attention that will perhaps change our outlook to perceive micro-organisms in relation to their physiological life style.

Afifella aestuarii sp. nov., a phototrophic bacterium.

An oval- to rod-shaped, motile, Gram-stain-negative, oxidase-positive, catalase-negative, pink-coloured phototrophic bacterium (designated as strain JA968T) was isolated from an estuary near Pata, Gujarat, India. Cells had an intracytoplasmic membrane architecture as lamellae and divided by budding. Strain JA968T had bacteriochlorophyll-a and spirilloxanthin series carotenoids as photosynthetic pigments. The strain exhibited photolithoautotrophic, photoorganoheterotrophic and chemoorganoheterotrophic growth modes and required thiamine as a growth factor. Strain JA968T had C18 : 1ω7c/C18  : 1ω6c as the predominant fatty acid with ubiquinone-10 (Q-10) and menaquinone-10 (MK-10) forming the quinone composition. The genomic DNA G+C content of the strain was 63.5 mol%. Pairwise comparison of 16S rRNA gene sequences showed that strain JA968T was highly similar to Afifella marina DSM 2698T (99.9 %) and Afifella pfennigii DSM 17143T (98.4 %). The average nucleotide identity values were 92 % between strain JA968T and A. marina DSM 2698T, and 78 % between strain JA968T and A. pfennigii DSM 17143T. The digital DNA-DNA hybridization values between strain JA968T and A. marina and A. pfennigii were 49 and 19 %, respectively. The genomic distinction was also supported by differences in phenotypic and chemotaxonomic characteristics. We propose that strain JA968T represents a new species of the genus Afifella with the name Afifella aestuarii sp. nov. The type strain is JA968T (=KCTC 15634T=NBRC 113338T).

iTRAQ-based quantitative proteomics reveals insights into metabolic and molecular responses of glucose-grown cells of Rubrivivax benzoatilyticus JA2.

Anoxygenic photosynthetic bacteria thrive under diverse habitats utilising an extended range of inorganic/organic compounds under different growth modes. Although they display incredible metabolic flexibility, their responses and adaptations to changing carbon regimes is largely unexplored. In the present study, we employed iTRAQ-based global proteomic profiling and physiological studies to uncover the adaptive strategies of a phototrophic bacterium, Rubrivivax benzoatilyticus JA2 to glucose. Strain JA2 displayed altered growth rates, reduced cell size and progressive loss of pigmentation when grown on glucose compared to malate under photoheterotrophic condition. A ten-fold increase in the saturated to unsaturated fatty acid ratio of glucose-grown cells indicates a possible membrane adaptation. Proteomic profiling revealed extensive metabolic remodelling in the glucose-grown cells wherein signal-transduction, selective-transcription, DNA-repair, transport and protein quality control processes were up-regulated to cope with the changing milieu. Proteins involved in DNA replication, translation, electron-transport, photosynthetic machinery were down-regulated possibly to conserve the energy. Glycolysis/gluconeogenesis, TCA cycle and pigment biosynthesis were also down-regulated. The cell has activated alternative energy metabolic pathways viz., fatty acid ß-oxidation, glyoxylate, acetate-switch and Entner-Doudoroff pathways. Overall, the present study deciphered the molecular/metabolic events associated with glucose-grown cells of strain JA2 and also unraveled how a carbon source modulates the metabolic phenotypes. SIGNIFICANCE: Anoxygenic photosynthetic bacteria (APB) exhibit incredible metabolic flexibility leading to diverse phenotypes. They thrive under diverse habitat using an array of inorganic/organic compounds as carbon sources, yet their metabolic adaptation to varying carbon regime is mostly unexplored. Present study uncovered the proteomic insights of the cellular responses of strain JA2 to changing carbon sources viz. malate and glucose under photoheterotrophic conditions. Our study suggests that carbon source can also determine the metabolic fate of the cells and reshape the energy dynamics of APB. Here, for the first time study highlighted the plausible carbon source (glucose) mediated regulation of photosynthesis in APB. The study sheds light on the plausible cellular events and adaptive metabolic strategies employed by strain JA2 in presence of non-preferred carbon source. It also revealed new insights into the metabolic plasticity of APB to the changing milieu.