High-throughput screening identifies cell cycle-associated signaling cascades that regulate a multienzyme glucosome assembly in human cells

We have previously demonstrated that human liver-type phosphofructokinase 1 (PFK1) recruits other rate-determining enzymes in glucose metabolism to organize multienzyme metabolic assemblies, termed glucosomes, in human cells. However, it has remained largely elusive how glucosomes are reversibly assembled and disassembled to functionally regulate glucose metabolism and thus contribute to human cell biology. We developed a high-content quantitative high-throughput screening (qHTS) assay to identify regulatory mechanisms that control PFK1-mediated glucosome assemblies from stably transfected HeLa Tet-On cells. Initial qHTS with a library of pharmacologically active compounds directed following efforts to kinase-inhibitor enriched collections. Consequently, three compounds that were known to inhibit cyclin-dependent kinase 2, ribosomal protein S6 kinase and Aurora kinase A, respectively, were identified and further validated under high-resolution fluorescence single-cell microscopy. Subsequent knockdown studies using small-hairpin RNAs further confirmed an active role of Aurora kinase A on the formation of PFK1 assemblies in HeLa cells. Importantly, all the identified protein kinases here have been investigated as key signaling nodes of one specific cascade that controls cell cycle progression in human cells. Collectively, our qHTS approaches unravel a cell cycle-associated signaling network that regulates the formation of PFK1-mediated glucosome assembly in human cells.

Insights into the Pseudocapacitive Behavior of Sulfurized Polymer Electrodes for Li-S Batteries

Practical applications of sulfurized polymer (SP) materials in Li-S batteries (LSBs) are often written off due to their low S content (≈35 wt%). Unlike conventional S₈ /C composite cathodes, SP materials are shown to function as pseudocapacitors with an active carbon backbone using a comprehensive array of tools including in situ Raman and electrochemical impedance spectroscopy. Critical metric analysis of LSBs containing SP materials with an active carbon skeleton shows that SP cathodes with 35 wt% S are suitable for 350 Wh kg^-1 target at the cell level if S loading >5 mg cm^-2 , electrolyte-to-sulfur ratio <2 µL mg^-1 , and negative-to-positive ratio <5 can be achieved. Although 3D current collectors can enable such high loadings, they often add excess mass decreasing the total capacity. An "active" carbon nanotube bucky sandwich current collector developed here offsets its excess weight by contributing to the electric double layer capacity. SP cathodes (35 wt% S) with ≈5.5 mg cm^-2 of S loading (≈15.8 mg cm^-2 of SP loading) yield a sulfur-level gravimetric capacity ≈1360 mAh g_s ^-1 (≈690 mAh g_s ^-1 ), electrode level capacity 200 mAh g_electrode ^-1 (100 mAh g_electrode ^-1 ), and areal capacity ≈7.8 mAh cm^-2 (≈4.0 mAh cm^-2 ) at 0.1C (1C) rate for ≈100 cycles at E/S ratio = 7 µL mg^-1 .

Cellulose/nanocellulose superabsorbent hydrogels as a sustainable platform for materials applications: A mini-review and perspective

Superabsorbent hydrogels (SAH) are crosslinked three-dimensional networks distinguished by their super capacity to stabilize a large quantity of water without dissolving. Such behavior enables them to engage in various applications. Cellulose and its derived nanocellulose can become SAHs as an appealing, versatile, and sustainable platform because of abundance, biodegradability, and renewability compared to petroleum-based materials. In this review, a synthetic strategy that reflects starting cellulosic resources to their associated synthons, crosslinking types, and synthetic controlling factors was highlighted. Representative examples of cellulose and nanocellulose SAH and an in-depth discussion of structure-absorption relationships were listed. Finally, various applications of cellulose and nanocellulose SAH, challenges and existing problems, and proposed future research pathways were listed.

Parabolic Potential Surfaces Localize Charge Carriers in Nonblinking Long-Lifetime "Giant" Colloidal Quantum Dots

Materials for studying biological interactions and for alternative energy applications are continuously under development. Semiconductor quantum dots are a major part of this landscape due to their tunable optoelectronic properties. Size-dependent quantum confinement effects have been utilized to create materials with tunable bandgaps and Auger recombination rates. Other mechanisms of electronic structural control are under investigation as not all of a material's characteristics are affected by quantum confinement. Demonstrated here is a new structure-property concept that imparts the ability to spatially localize electrons or holes within a core/shell heterostructure by tuning the charge carrier's kinetic energy on a parabolic potential energy surface. This charge carrier separation results in extended radiative lifetimes and in continuous emission at the single-nanoparticle level. These properties enable new applications for optics, facilitate novel approaches such as time-gated single-particle imaging, and create inroads for the development of other new advanced materials.

β-V2O5 as Magnesium Intercalation Cathode

Magnesium batteries have attracted great attention as an alternative to Li-ion batteries but still suffer from limited choice of positive electrode materials. V₂O₅ exhibits high theoretical capacities, but previous studies have been mostly limited to α-V₂O₅. Herein, we report on the β-V₂O₅ polymorph as a Mg intercalation electrode. The structural changes associated with the Mg²⁺ (de-) intercalation were analyzed by a combination of several characterization techniques: in situ high resolution X-ray diffraction, scanning transmission electron microscopy, electron energy-loss spectroscopy, and X-ray absorption spectroscopy. The reversible capacity reached 361 mAh g^-1, the highest value found at room temperature for V₂O₅ polymorphs.

Phonon anharmonicity in binary chalcogenides for efficient energy harvesting

Thermoelectric (TE) materials have received much attention due to their ability to harvest waste heat energy. TE materials must exhibit a low thermal conductivity (κ) and a high power factor (PF) for efficient conversion. Both factors define the figure of merit (ZT) of the TE material, which can be increased by suppressing κ without degrading the PF. Recently, binary chalcogenides such as SnSe, GeTe, and PbTe have emerged as attractive candidates for thermoelectric energy generation at moderately high temperatures. These materials possess simple crystal structures with low κ in their pristine forms, which can be further lowered through doping and other approaches. Here, we review the recent advances in the temperature-dependent behavior of phonons and their influence on the thermal transport properties of chalcogenide-based TE materials. Because phonon anharmonicity is one of the fundamental contributing factors for low thermal conductivity in SnSe, Sb-doped GeTe, and related chalcogenides, we discuss complementary experimental approaches such as temperature-dependent Raman spectroscopy, inelastic neutron scattering, and calorimetry to measure anharmonicity. We further show how data gathered using multiple techniques helps us understand and engineer better TE materials. Finally, we discuss the rise of machine learning-aided efforts to discover, design, and synthesize TE materials of the future.

Investigation of Ca Insertion into α-MoO3 Nanoparticles for High Capacity Ca-Ion Cathodes

Calcium-ion batteries (CIBs) are a promising alternative to lithium-ion batteries (LIBs) due to the low redox potential of calcium metal and high abundance of calcium compounds. Due to its layered structure, α-MoO₃ is regarded as a promising cathode host lattice. While studies have reported that α-MoO₃ can reversibly intercalate Ca ions, limited electrochemical activity has been noted, and its reaction mechanism remains unclear. Here, we re-examine Ca insertion into α-MoO₃ nanoparticles with a goal to improve reaction kinetics and clarify the storage mechanism. The α-MoO₃ electrodes demonstrated a specific capacity of 165 mA h g^-1 centered near 2.7 V vs Ca²⁺/Ca, stable long-term cycling, and good rate performance at room temperature. This work demonstrates that, under the correct conditions, layered oxides can be a promising host material for CIBs and renews prospects for CIBs.

Multi-dimensional Fluorescence Live-Cell Imaging for Glucosome Dynamics in Living Human Cells

Fluorescence live-cell imaging that has contributed to our understanding of cell biology is now at the frontline of studying quantitative biochemistry in a cell. Particularly, technological advancements of fluorescence live-cell imaging and associated strategies in recent years have allowed us to discover various subcellular macromolecular assemblies in living human cells. Here we describe how real-time dynamics of a multienzyme metabolic assembly, the "glucosome," that is responsible for regulating glucose flux at subcellular levels, has been investigated in both 2- and 3-dimensional space of single human cells. We envision that such multi-dimensional fluorescence live-cell imaging will continue to revolutionize our understanding of how intracellular metabolic pathways and their network are functionally orchestrated at single-cell levels.

Utilization of Cellulose to Its Full Potential: A Review on Cellulose Dissolution, Regeneration, and Applications

As the most abundant natural polymer, cellulose is a prime candidate for the preparation of both sustainable and economically viable polymeric products hitherto predominantly produced from oil-based synthetic polymers. However, the utilization of cellulose to its full potential is constrained by its recalcitrance to chemical processing. Both fundamental and applied aspects of cellulose dissolution remain active areas of research and include mechanistic studies on solvent-cellulose interactions, the development of novel solvents and/or solvent systems, the optimization of dissolution conditions, and the preparation of various cellulose-based materials. In this review, we build on existing knowledge on cellulose dissolution, including the structural characteristics of the polymer that are important for dissolution (molecular weight, crystallinity, and effect of hydrophobic interactions), and evaluate widely used non-derivatizing solvents (sodium hydroxide (NaOH)-based systems, N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl), N-methylmorpholine-N-oxide (NMMO), and ionic liquids). We also cover the subsequent regeneration of cellulose solutions from these solvents into various architectures (fibers, films, membranes, beads, aerogels, and hydrogels) and review uses of these materials in specific applications, such as biomedical, sorption, and energy uses.

Advances in Studies of Boron Nitride Nanosheets and Nanocomposites for Thermal Transport and Related Applications

Hexagonal boron nitride (h-BN) and exfoliated nanosheets (BNNs) not only resemble their carbon counterparts graphite and graphene nanosheets in structural configurations and many excellent materials characteristics, especially the ultra-high thermal conductivity, but also offer other unique properties such as being electrically insulating and extreme chemical stability and oxidation resistance even at elevated temperatures. In fact, BNNs as a special class of 2-D nanomaterials have been widely pursued for technological applications that are beyond the reach of their carbon counterparts. Highlighted in this article are significant recent advances in the development of more effective and efficient exfoliation techniques for high-quality BNNs, the understanding of their characteristic properties, and the use of BNNs in polymeric nanocomposites for thermally conductive yet electrically insulating materials and systems. Major challenges and opportunities for further advances in the relevant research field are also discussed.

Production and Surface Modification of Cellulose Bioproducts

Petroleum-based synthetic plastics play an important role in our life. As the detrimental health and environmental effects of synthetic plastics continue to increase, the renewable, degradable and recyclable properties of cellulose make subsequent products the "preferred environmentally friendly" alternatives, with a small carbon footprint. Despite the fact that the bioplastic industry is growing rapidly with many innovative discoveries, cellulose-based bioproducts in their natural state face challenges in replacing synthetic plastics. These challenges include scalability issues, high cost of production, and most importantly, limited functionality of cellulosic materials. However, in order for cellulosic materials to be able to compete with synthetic plastics, they must possess properties adequate for the end use and meet performance expectations. In this regard, surface modification of pre-made cellulosic materials preserves the chemical profile of cellulose, its mechanical properties, and biodegradability, while diversifying its possible applications. The review covers numerous techniques for surface functionalization of materials prepared from cellulose such as plasma treatment, surface grafting (including RDRP methods), and chemical vapor and atomic layer deposition techniques. The review also highlights purposeful development of new cellulosic architectures and their utilization, with a specific focus on cellulosic hydrogels, aerogels, beads, membranes, and nanomaterials. The judicious choice of material architecture combined with a specific surface functionalization method will allow us to take full advantage of the polymer's biocompatibility and biodegradability and improve existing and target novel applications of cellulose, such as proteins and antibodies immobilization, enantiomers separation, and composites preparation.

Bi2O3 nano-flakes as a cost-effective antibacterial agent

Bismuth oxide is an important bismuth compound having applications in electronics, photo-catalysis and medicine. At the nanoscale, bismuth oxide experiences a variety of new physico-chemical properties because of its increased surface to volume ratio leading to potentially new applications. In this manuscript, we report for the very first time the synthesis of bismuth oxide (Bi₂O₃) nano-flakes by pulsed laser ablation in liquids without any external assistance (no acoustic, electric field, or magnetic field). The synthesis was performed by irradiating, pure bismuth needles immerged in de-ionized water, at very high fluence ∼160 J cm^-2 in order to be highly selective and only promote the growth of two-dimensional structures. The x- and y-dimensions of the flakes were around 1 μm in size while their thickness was 47.0 ± 12.7 nm as confirmed by AFM analysis. The flakes were confirmed to be α- and γ-Bi₂O₃ by SAED and Raman spectroscopy. By using this mixture of flakes, we demonstrated that the nanostructures can be used as antimicrobial agents, achieving a complete inhibition of Gram positive (MSRA) and Gram negative bacteria (MDR-EC) at low concentration, ∼50 ppm.

Control of crystal size tailors the electrochemical performance of α-V2O5 as a Mg2+ intercalation host

α-V₂O₅ has been extensively explored as a Mg²⁺ intercalation host with potential as a battery cathode, offering high theoretical capacities and potentials vs. Mg²⁺/Mg. However, large voltage hysteresis is observed with Mg insertion and extraction, introducing significant and unacceptable round-trip energy losses with cycling. Conventional interpretations suggest that bulk ion transport of Mg²⁺ within the cathode particles is the major source of this hysteresis. Herein, we demonstrate that nanosizing α-V₂O₅ gives a measurable reduction to voltage hysteresis on the first cycle that substantially raises energy efficiency, indicating that mechanical formatting of the α-V₂O₅ particles contributes to hysteresis. However, no measurable improvement in hysteresis is found in the nanosized α-V₂O₅ in latter cycles despite the much shorter diffusion lengths, suggesting that other factors aside from Mg transport, such as Mg transfer between the electrolyte and electrode, contribute to this hysteresis. This observation is in sharp contrast to the conventional interpretation of Mg electrochemistry. Therefore, this study uncovers critical fundamental underpinning limiting factors in Mg battery electrochemistry, and constitutes a pivotal step towards a high-voltage, high-capacity electrode material suitable for Mg batteries with high energy density.

Dementia Symptoms among Senior Citizens Living in Geriatric Homes of Kathmandu Valley

Background With increasing age, the older population becomes more susceptible to mental disorders. It is important to recognize and develop an understanding of psychiatric morbidity particularly among the residents of geriatric homes in resource-poor settings. Objective To assess the prevalence and associated factors of dementia symptoms among Nepalese senior citizens living in geriatric homes of Kathmandu valley. Method A cross-sectional study was conducted among 304 senior citizens living in geriatric homes of Kathmandu valley. Cognitive Impairment Test (CIT), was used to assess dementia symptoms. Bivariate and multivariate logistic regressions were performed. All the variables that were significant at p < 0.05 level in the bivariate analysis were included in the multivariate regression model and statistical significance was declared at p < 0.05 with a 95.00% confidence interval (CI). Result This study showed 75.65%, of the participants, had dementia symptoms. In the multivariate logistic regression analysis, female respondents (AOR=2.94, 95% CI=1.31-6.57), respondents never received geriatric allowances (AOR=2.46, 95% CI=1.22-4.98), respondent's history of alcohol consumption habits (AOR=2.04, 95% CI=1.01-4.11) and non-vegetarian diet habits (AOR= 2.31, 95% CI=1.12-4.76) were found more likely to had higher dementia symptoms whereas, literate participants (AOR=0.19, 95% CI=0.08-0.43) were less likely to had dementia symptoms. Conclusion The high prevalence of dementia symptoms among senior citizens living in geriatric homes in the Kathmandu valley indicates an urgent need for early diagnosis and treatment of mental disorders among senior citizens to improve their quality of life and well-being.

High zT and Its Origin in Sb-doped GeTe Single Crystals

A record high zT of 2.2 at 740 K is reported in Ge0.92Sb0.08Te single crystals, with an optimal hole carrier concentration ≈4 × 1020 cm-3 that simultaneously maximizes the power factor (PF) ≈56 µW cm-1 K-2 and minimizes the thermal conductivity ≈1.9 Wm-1 K-1. In addition to the presence of herringbone domains and stacking faults, the Ge0.92Sb0.08Te exhibits significant modification to phonon dispersion with an extra phonon excitation around ≈5-6 meV at Γ point of the Brillouin zone as confirmed through inelastic neutron scattering (INS) measurements. Density functional theory (DFT) confirmed this phonon excitation, and predicted another higher energy phonon excitation ≈12-13 meV at W point. These phonon excitations collectively increase the number of phonon decay channels leading to softening of phonon frequencies such that a three-phonon process is dominant in Ge0.92Sb0.08Te, in contrast to a dominant four-phonon process in pristine GeTe, highlighting the importance of phonon engineering approaches to improving thermoelectric (TE) performance.

Enhanced charge storage of nanometric ζ-V2O5 in Mg electrolytes

V2O5 is of interest as a Mg intercalation electrode material for Mg batteries, both in its thermodynamically stable layered polymorph (α-V2O5) and in its metastable tunnel structure (ζ-V2O5). However, such oxide cathodes typically display poor Mg insertion/removal kinetics, with large voltage hysteresis. Herein, we report the synthesis and evaluation of nanosized (ca. 100 nm) ζ-V2O5 in Mg-ion cells, which displays significantly enhanced electrochemical kinetics compared to microsized ζ-V2O5. This effect results in a significant boost in stable discharge capacity (130 mA h g-1) compared to bulk ζ-V2O5 (70 mA h g-1), with reduced voltage hysteresis (1.0 V compared to 1.4 V). This study reveals significant advancements in the use of ζ-V2O5 for Mg-based energy storage and yields a better understanding of the kinetic limiting factors for reversible magnesiation reactions into such phases.

Quasi-Binary Transition Metal Dichalcogenide Alloys: Thermodynamic Stability Prediction, Scalable Synthesis, and Application

Transition metal dichalcogenide (TMDCs) alloys could have a wide range of physical and chemical properties, ranging from charge density waves to superconductivity and electrochemical activities. While many exciting behaviors of unary TMDCs have been demonstrated, the vast compositional space of TMDC alloys has remained largely unexplored due to the lack of understanding regarding their stability when accommodating different cations or chalcogens in a single-phase. Here, a theory-guided synthesis approach is reported to achieve unexplored quasi-binary TMDC alloys through computationally predicted stability maps. Equilibrium temperature-composition phase diagrams using first-principles calculations are generated to identify the stability of 25 quasi-binary TMDC alloys, including some involving non-isovalent cations and are verified experimentally through the synthesis of a subset of 12 predicted alloys using a scalable chemical vapor transport method. It is demonstrated that the synthesized alloys can be exfoliated into 2D structures, and some of them exhibit: i) outstanding thermal stability tested up to 1230 K, ii) exceptionally high electrochemical activity for the CO₂ reduction reaction in a kinetically limited regime with near zero overpotential for CO formation, iii) excellent energy efficiency in a high rate Li-air battery, and iv) high break-down current density for interconnect applications. This framework can be extended to accelerate the discovery of other TMDC alloys for various applications.

Rapid detection of urokinase plasminogen activator using flexible paper-based graphene-gold platform

Many studies have shown that urokinase plasminogen activator (uPA) is causally involved in promoting cancer invasion and metastasis. Thus, monitoring uPA levels could be very useful in cancer diagnosis, identification of initial metastasis, and guiding cancer treatment. Here, the authors developed a novel and scalable uPA sensor based on a graphene-gold nanoparticle platform that uses fluorescence of quantum dots to rapidly (<1 h) detect uPA up to 100 pM. Indeed, the authors' sensor is highly selective and showed an ability to sense up to 100 pM uPA even in the presence of complex biological milieu such as the fetal bovine serum.

Effect of Hand Held Vibrating Tools on Nerve Conduction Study in Dental Residents

BACKGROUND

Repetitive exposure to vibration has been shown to induce peripheral nerve dysfunction. Dentists are exposed to handheld vibrating tools in their daily clinical practice. Most of the studies are done in dentists who have symptoms such as paresthesia and numbness of the hands. Thus, we conducted the study to explore the effect of vibration on nerve conduction variables in apparently healthy asymptomatic dental residents.

METHODS

This cross-sectional study enrolled 22 dental residents and age matched 22 medical residents as controls. Nerve conduction study was performed in median and ulnar nerves of both hands.

RESULTS

Anthropometric and cardiorespiratory variables were comparable between the groups. There were no statistically significant differences between dental and medical residents in the sensory conduction variables (right median onset latency=2.05±0.27 vs 1.91±0.21, p value=0.07; right median amplitude =27.80±8.11 vs 29.55±7.04, p=0.45; right median conduction velocity = 59.54±7.05 vs 61.06±5.15, p= 0.42) and motor conduction variables (right median distal latency = 2.87±0.38 vs 2.87±0.38, p= 0.94; right median distal amplitude=10.71±2.19 vs 11.10±2.37, p=0.58; right median conduction velocity= 70.57±13.16 vs 68.53±7.73, p= 0.54) of median and ulnar nerves. Further, there was no significant difference between the dominant and non-dominant hands of dental residents.

CONCLUSIONS

Hand held vibration tools did not alter nerve conduction study parameters of dental residents.

Two Trifunctional Leloir Glycosyltransferases as Biocatalysts for Natural Products Glycodiversification

Two promiscuous Bacillus licheniformis glycosyltransferases, YdhE and YojK, exhibited prominent stereospecific but nonregiospecific glycosylation activity of 20 different classes of 59 structurally different natural and non-natural products. Both enzymes transferred various sugars at three nucleophilic groups (OH, NH₂, SH) of diverse compounds to produce O-, N-, and S-glycosides. The enzymes also displayed a catalytic reversibility potential for a one-pot transglycosylation, thus bestowing a cost-effective application in biosynthesis of glycodiversified natural products in drug discovery.

Combinatorial approach for improved cyanidin 3-O-glucoside production in Escherichia coli

BACKGROUND

Multi-monocistronic and multi-variate vectors were designed, built, and tested for the improved production of cyanidin 3-O-glucoside (C3G) in Escherichia coli BL21 (DE3). The synthetic bio-parts were designed in such a way that multiple genes can be assembled using the bio-brick system, and expressed under different promoters in a single vector. The vectors harbor compatible cloning sites, so that the genes can be shuffled from one vector to another in a single step, and assembled into a single vector. The two required genes: anthocyanidin synthase (PhANS) from Petunia hybrida, and cyanidin 3-O-glucosyltransferase (At3GT) from Arabidopsis thaliana, were individually cloned under PT7, Ptrc, and PlacUV5 promoters. Both PhANS and At3GT were shuffled back and forth, so as to generate a combinatorial system for C3G production. The constructed systems were further coupled with the genes for UDP-D-glucose synthesis, all cloned in a multi-monocistronic fashion under PT7. Finally, the production of C3G was checked and confirmed using the modified M9 media, and analyzed through various chromatography and spectrometric analyses.

RESULTS

The engineered strains endowed with newly generated vectors and the genes for C3G biosynthesis and UDP-D-glucose synthesis were fed with 2 mM (+)-catechin and D-glucose for the production of cyanidin, and its subsequent conversion to C3G. One of the engineered strains harboring At3GT and PhANS under Ptrc promoter and UDP-D-glucose biosynthesis genes under PT7 promoter led to the production of ~ 439 mg/L of C3G within 36 h of incubation, when the system was exogenously fed with 5% (w/v) D-glucose. This system did not require exogenous supplementation of UDP-D-glucose.

CONCLUSION

A synthetic vector system using different promoters has been developed and used for the synthesis of C3G in E. coli BL21 (DE3) by directing the metabolic flux towards the UDP-D-glucose. This system has the potential of generating better strains for the synthesis of valuable natural products.

Orthorhombic distortion in Au nanoparticles induced by high pressure

A shape-dependent orthorhombic lattice distortion is induced in Au nanoparticles below 12 GPa in a DAC.

One-Pot Multienzyme Cofactors Recycling (OPME-CR) System for Lactose and Non-natural Saccharide Conjugated Polyphenol Production

A one-pot multienzyme cofactors recycling (OPME-CR) system was designed for the synthesis of UDP-α-d-galactose, which was combined with LgtB, a β-(1,4) galactosyltransferase from Neisseria meningitidis, to modify various polyphenol glycosides. This system recycles one mole of ADP and one mole of UDP to regenerate one mole of UDP-α-d-galactose by consuming two moles of acetylphosphate and one mole of d-galactose in each cycle. The ATP additionally used to generate UDP from UMP was also recycled at the beginning of the reaction. The engineered cofactors recycling system with LgtB efficiently added a d-galactose unit to a variety of sugar units such as d-glucose, rutinose, and 2-deoxy-d-glucose. The temperature, pH, incubation time, and divalent metal ions for the OPME-CR system were optimized. The maximum number of UDP-α-d-galactose regeneration cycles (RC_max) was 18.24 by fed batch reaction. The engineered system generated natural and non-natural polyphenol saccharides efficiently and cost-effectively.

Biosynthesis of flavone C-glucosides in engineered Escherichia coli

Two plant-originated C-glucosyltransferases (CGTs) UGT708D1 from Glycine max and GtUF6CGT1 from Gentiana triflora were accessed for glucosylation of selected flavones chrysin and luteolin. Uridine diphosphate (UDP)-glucose pool was enhanced in Escherichia coli cell cytosol by introducing heterologous UDP-glucose biosynthetic genes, i.e., glucokinase (glk), phosphoglucomutase (pgm2), and glucose 1-phosphate uridylyltransferase (galU), along with glucose facilitator diffusion protein from (glf) from different organisms, in a multi-monocistronic vector with individual T7 promoter, ribosome binding site, and terminator for each gene. The C-glucosylated products were analyzed by high-performance liquid chromatography-photodiode array, high-resolution quadruple time-of-flight electrospray ionization mass spectrometry, and one-dimensional nuclear magnetic resonance analyses. Fed-batch shake flask culture showed 8% (7 mg/L; 16 μM) and 11% (9 mg/L; 22 μM) conversion of chrysin to chrysin 6-C-β-D-glucoside with UGT708D1 and GtUF6CGT1, respectively. Moreover, the bioengineered E. coli strains with exogenous UDP-glucose biosynthetic genes and glucose facilitator diffusion protein enhanced the production of chrysin 6-C-β-D-glucoside by approximately 1.4-fold, thus producing 10 mg/L (12%, 24 μM) and 14 mg/L (17%, 34 μM) by UGT708D1 and GtUF6CGT1, respectively, without supplementation of additional UDP-glucose in the medium. The biotransformation was further elevated when the bioengineered strain was scaled up in lab-scale fermentor at 3 L volume. HPLC analysis of fermentation broth extract revealed 50% (42 mg/L, 100 μM) conversion of chrysin to chrysin 6-C-β-D-glucoside at 48 h upon supplementation of 200 μM of chrysin. The maximum conversion of luteolin was 38% (34 mg/L, 76 μM) in 50-mL shake flask fermentation at 48 h. C-glucosylated derivative of chrysin was found to be more soluble and more stable to high temperature, different pH range, and β-glucosidase enzyme, than O-glucosylated derivative of chrysin.

Knowledge Regarding Earthquake Preparedness Among the People of Biratnagar Sub-Metropolis of Eastern Nepal

IntroductionEarthquake preparedness is necessary strategy and action that is done before an earthquake happens in order to decrease mortality and morbidity. Earthquake in Nepal killed more than 8000 people in 2015. Increased number of deaths were mainly considered due to lack of earthquake preparedness and necessary safety measures.ObjectivesThe aim of this study was to assess the knowledge regarding earthquake preparedness and to find out relationship between the level of knowledge and with their selected socio-demographic variables.MethodologyA cross sectional study was conducted among the people residing in ward number 11 and 18 of Biratnagar sub-metropolis from 1st July to 1st October 2015. Wards were selected through simple random sampling and 110 participants were selected through convenient sampling. Each participant had completed an interviewer-administered questionnaire. Descriptive and inferential statistics was applied for data analysis.ResultAmong 110 participants, 51.8% had knowledge score between 51% to 75%, 24.6% had knowledge score below 50% and only 23.6% had knowledge score above 75%. This research showed that there was significant relationship between knowledge and age, marital status, educational status, occupation and monthly income. Participants from 20 to 39 year had more knowledge score than participants from 40 to 60 years. The higher the educational status; more was the knowledge score. Unmarried participants had more knowledge score than married participants and business holders had more knowledge score than other occupation category.ConclusionEarthquake preparedness knowledge among participants was inadequate. Therefore, educational intervention program regarding this is required in these areas. Birat Journal of Health Sciences Vol.2/No.1/Issue 2/ Jan - April 2017, page: 201-205

Diabetes Awareness Among Patient's Attendant Visiting in Teaching Hospital of Eastern Nepal

IntroductionDiabetes is a prevalent non-communicable disease. It has  increasing global trend. In Nepal, the prevalence of diabetes is also increasing. Awareness is vital to  revent and early diagnosis of diabetes.ObjectivesThe objective of study was to assess the awareness of diabetes and its related factors.MethodologyThis was a hospital based cross sectional study. Total of 503 patient's a

Treatment Outcome of Drug Resistance Tuberculosis From a Centre of Eastern Region, Nepal

Introduction Drug resistance tuberculosis (DRTB) has become major problem worldwide with difficulty in treatment. Objective The study is conducted to find the incidence and outcomes of DRTB in one of the eastern tuberculosis treatment centre of Nepal.Methodology We collected all the cases of DRTB being treated from national anti-tuberculosis association of Biratnagar, Nepal. There were altogether 154 patients, who had sputum culture with resistance of at least one anti tubercular drug (ATD), included in this study.Results Of 154 total patients, 36 patients were resistant to rifampicin only, 84 patients were resistant to isoniazid and rifampicin, 18 patients were resistant to isoniazid, rifampicin and ethambutol and 16 patients were resistant to isoniazid, rifampicin and either streptomycin or fluoroquinolone. There was overall 71% cure rate in case of drug resistance tuberculosis. There was only statistical difference between cured and died patients in case of sputum conversion time with earlier sputum conversion in cured patients. Similarly, patients who were previously treated with category 2 ATD had only resistance to ethambutol or streptomycin or fluoroquinolone besides resistance to isoniazid and rifampicin compared to new patients and patients treated with category 1 regimen; as these groups were not found to be resistant to first three drugs.Conclusion There was overall 71% cure rate in case of drug resistance tuberculosis. Earlier sputum conversion was seen in cured patients compared to those who died during the treatment. Multiple drugs were resistant in patients previously treated with category 2 Anti-tubercular drugs.Birat Journal of Health Sciences 2016 1(1): 20-26

Effectiveness of Educational Intervention Programme on Knowledge Regarding Breast Self Examination Among Higher Secondary School Girls of Biratnagar

Introduction Breast self-examination (BSE) is a self-generated, non-invasive and non-irradiative method of breast cancer detection. Self examination of the breasts each month after the menstrual cycle is the simplest yet extremely important way to detect early breast cancer. It has been observed that women can detect 95% of breast cancers and 65% of early minimal breast cancers themselves. This method is harmless, less time consuming and can be performed by any woman.Objective To assess the effectiveness of educational intervention programme regarding Breast Self Examination among girl students of study school.Methodology Pre experimental one group pre-test post-test design was adopted for this study. In total, 61 girls were included. The result were analysed by using both descriptive as well as inferential statistics.Results In pre-test 75.4% had inadequate and only 1.6% had adequate knowledge regarding Breast Self Examination, in contrast, after the intervention the adequate knowledge was increased to 62.3%. The overall mean score was increased from 33.07% to 85.14%. The test of significance revealed that the increment in BSE knowledge score due to program intervention was highly significant (P< 0.001).Conclusion The educational intervention programme on BSE was found to be highly effective as the knowledge score was significantly increased after intervention of the package among higher secondary school girls.Birat Journal of Health Sciences 2016 1(1): 13-19

Biosynthesis of natural and non-natural genistein glycosides

Biosynthesis of various genistein glycopyranoside scaffolds using versatile GTs and SOMTs. Each compound was structurally characterized and biological activity assay was carried out.

Enhanced production of nargenicin A1 and creation of a novel derivative using a synthetic biology platform

Nargenicin A1, an antibacterial produced by Nocardia sp. CS682 (KCTC 11297BP), demonstrates effective activity against various Gram-positive bacteria. Hence, we attempted to enhance nargenicin A1 production by utilizing the cumulative effect of synthetic biology, metabolic engineering and statistical media optimization strategies. To facilitate the modular assembly of multiple genes for genetic engineering in Nocardia sp. CS682, we constructed a set of multi-monocistronic vectors, pNV18L1 and pNV18L2 containing hybrid promoter (derived from ermE* and promoter region of neo ^r ), ribosome binding sites (RBS), and restriction sites for cloning, so that each cloned gene was under its own promoter and RBS. The multi-monocistronic vector, pNV18L2 containing transcriptional terminator showed better efficiency in reporter gene assay. Thus, multiple genes involved in the biogenesis of pyrrole moiety (ngnN2, ngnN3, ngnN4, and ngnN5 from Nocardia sp. CS682), glucose utilization (glf and glk from Zymomonas mobilis), and malonyl-CoA synthesis (accA2 and accBE from Streptomyces coelicolor A3 (2)), were cloned in pNV18L2. Further statistical optimization of specific precursors (proline and glucose) and their feeding time led to ~84.9 mg/L nargenicin from Nocardia sp. GAP, which is ~24-fold higher than Nocardia sp. CS682 (without feeding). Furthermore, pikC from Streptomyces venezuelae was expressed to generate Nocardia sp. PikC. Nargenicin A1 acid was characterized as novel derivative of nargenicin A1 produced from Nocardia sp. PikC by mass spectrometry (MS) and nuclear magnetic resonance (NMR) analyses. We also performed comparative analysis of the anticancer and antibacterial activities of nargenicin A1 and nargenicin A1 acid, which showed a reduction in antibacterial potential for nargenicin A1 acid. Thus, the development of an efficient synthetic biological platform provided new avenues for enhancing or structurally diversifying nargenicin A1 by means of pathway designing and engineering.

Enhanced production of nargenicin A1 and creation of a novel derivative using a synthetic biology platform

Nargenicin A1, an antibacterial produced by Nocardia sp. CS682 (KCTC 11297BP), demonstrates effective activity against various Gram-positive bacteria. Hence, we attempted to enhance nargenicin A1 production by utilizing the cumulative effect of synthetic biology, metabolic engineering and statistical media optimization strategies. To facilitate the modular assembly of multiple genes for genetic engineering in Nocardia sp. CS682, we constructed a set of multi-monocistronic vectors, pNV18L1 and pNV18L2 containing hybrid promoter (derived from ermE* and promoter region of neo ^r ), ribosome binding sites (RBS), and restriction sites for cloning, so that each cloned gene was under its own promoter and RBS. The multi-monocistronic vector, pNV18L2 containing transcriptional terminator showed better efficiency in reporter gene assay. Thus, multiple genes involved in the biogenesis of pyrrole moiety (ngnN2, ngnN3, ngnN4, and ngnN5 from Nocardia sp. CS682), glucose utilization (glf and glk from Zymomonas mobilis), and malonyl-CoA synthesis (accA2 and accBE from Streptomyces coelicolor A3 (2)), were cloned in pNV18L2. Further statistical optimization of specific precursors (proline and glucose) and their feeding time led to ~84.9 mg/L nargenicin from Nocardia sp. GAP, which is ~24-fold higher than Nocardia sp. CS682 (without feeding). Furthermore, pikC from Streptomyces venezuelae was expressed to generate Nocardia sp. PikC. Nargenicin A1 acid was characterized as novel derivative of nargenicin A1 produced from Nocardia sp. PikC by mass spectrometry (MS) and nuclear magnetic resonance (NMR) analyses. We also performed comparative analysis of the anticancer and antibacterial activities of nargenicin A1 and nargenicin A1 acid, which showed a reduction in antibacterial potential for nargenicin A1 acid. Thus, the development of an efficient synthetic biological platform provided new avenues for enhancing or structurally diversifying nargenicin A1 by means of pathway designing and engineering.

Modulation of Hemopoiesis in Normal and Tumor-Bearing Mice on in Vivo Administration of FK565

The present investigations were undertaken to study the effect of in vivo administration of FK565 on the process of hemopoiesis in normal and tumor-bearing mice. FK565 administration (10 mg/kg body weight) of normal mice resulted in an enhancement of the bone marrow cell (BMC) colony foming activity (CFA) and proliferation in vitro. The counts of granulocyte- and granulocyte macrophage-colony forming units (CFU-G and CFU-GM) were significantly enhanced in the BMC of FK565-treated group. The total leukocyte count (TLC) was also augmented after FK565 administration. The differential leukocyte count (DLC) revealed an enhancement of the neutrophil count in the FK565-treated mice. A similar pattern of BMC proliferation, CFA, TLC and DLC was observed in P815 tumor-bearing mice. FK565 administration of the tumor-bearing mice, however, did not significantly alter the CFA, TLC and DLC.

Donor specificity of YjiC glycosyltransferase determines the conjugation of cytosolic NDP-sugar in in vivo glycosylation reactions

Escherichia coli BL21 (DE3) was engineered by blocking glucose-1-phosphate utilizing glucose phosphate isomerase (pgi), glucose-6-phosphate dehydrogenase (zwf) and uridylyltransferase (galU) genes to produce pool of four different rare dTDP-sugars. The cytosolic pool of dTDP-l-rhamnose, dTDP-d-viosamine, dTDP-4-amino 4,6-dideoxy-d-galactose, and dTDP-3-amino 3,6-dideoxy-d-galactose was generated by overexpressing respective dTDP-sugars biosynthesis genes from various microbial sources. A flexible glycosyltransferase YjiC, from Bacillus licheniformis DSM 13 was also overexpressed to transfer sugar moieties to 3-hydroxyl group of 3-hydroxyflavone, a core unit of flavonoids. Among four rare dTDP-sugars generated in cytosol of engineered strains, YjiC solely transferred l-rhamnose from dTDP-l-rhamnose and tuned to rhamnosyltransferase.

Anti-proliferative effects of γ-tocotrienol are associated with suppression of c-Myc expression in mammary tumour cells

OBJECTIVES

Aberrant c-Myc activity plays a central role in cancer transformation. γ-tocotrienol is a member of the vitamin E family that displays potent anti-cancer activity. Here, studies were conducted to determine the role of c-Myc in mediating anti-proliferative effects of γ-tocotrienol in mammary cancer cells.

MATERIALS AND METHODS

Treatment effects on mouse +SA and human MCF-7 mammary cancer cell proliferation were determined by MTT assay and Ki-67 staining. Protein expression was determined by western blot analysis. Immunofluorescence staining and qRT-PCR were used to characterize cellular c-Myc and MYC levels respectively.

RESULTS

Anti-proliferative effects of γ-tocotrienol were associated with reduction in total c-Myc and phosphorylated-c-Myc-serine 62, and increase in phosphorylated-c-Myc-threonine 58 levels. γ-tocotrienol also reduced PI3K/Akt/mTOR and Ras/MEK/Erk mitogenic signalling, cyclin D1 and cyclin-dependent kinase 4 levels, and increased p27 levels. However, γ-tocotrienol had no effect on MYC mRNA levels. γ-tocotrienol also increased levels of FBW7 (E3 ligase that initiates ubiquitination of c-Myc), but had no effect on serine/threonine phosphatase PP2A or isomerase Pin 1 levels. Combined treatment with GSK3α/β inhibitor LiCl or proteasome inhibitor MG132 blocked γ-tocotrienol-induced reductions in c-Myc.

CONCLUSIONS

These findings indicate that anti-proliferative effects of γ-tocotrienol are associated with reduction in c-Myc that results from increase in GSK-3α/β-dependent ubiquitination and degradation, rather than from reduction in c-Myc synthesis in +SA and MCF-7 mammary cancer cells.

Synthetic sugar cassettes for the efficient production of flavonol glycosides in Escherichia coli

Background

A multi-monocistronic synthetic vector was used to assemble multiple genes of a nucleotide diphosphate (NDP)-sugar biosynthetic pathway to construct robust genetic circuits for the production of valuable flavonoid glycosides in Escherichia coli. Characterized functional genes involved in the biosynthesis of uridine diphosphate (UDP)-glucose and thymidine diphosphate (TDP)-rhamnose from various microbial sources along with glucose facilitator diffusion protein (glf) and glucokinase (glk) from Zymomonas mobilis were assembled and overexpressed in a single synthetic multi-monocistronic operon.

Results

The newly generated NDP-sugars biosynthesis circuits along with regiospecific glycosyltransferases from plants were introduced in E. coli BL21 (DE3) to probe the bioconversion of fisetin, a medicinally important polyphenol produced by various plants. As a result, approximately 1.178 g of fisetin 3-O-glucoside and 1.026 g of fisetin 3-O-rhamnoside were produced in UDP-glucose and TDP-rhamnose biosynthesis systems respectively, after 48 h of incubation in 3 L fermentor while supplementing 0.9 g of fisetin. These yields of fisetin glycosides represent ~99% of bioconversion of exogenously supplemented fisetin. The systems were also found to be highly effective in bio-transforming other flavonols (quercetin, kaempferol, myricetin) into their respective glycosides, achieving over 95% substrate conversion.

Conclusion

The construction of a synthetic expression vector for bacterial cell factory followed by subsequent re-direction of metabolic flux towards desirable products have always been revolutionized the biotechnological processes and technologies. This multi-monocistronic synthetic vector in a microbial platform is customizable to defined task and would certainly be useful for applications in producing and modifying such therapeutically valued plant secondary metabolites.

Electronic supplementary material

The online version of this article (doi:10.1186/s12934-015-0261-1) contains supplementary material, which is available to authorized users.

Enhanced production of nargenicin A(1) and generation of novel glycosylated derivatives

Nargenicin A1, an antibacterial polyketide macrolide produced by Nocardia sp. CS682, was enhanced by increasing the pool of precursors using different sources. Furthermore, by using engineered strain Nocardia sp. ACC18 and supplementation of glucose and glycerol, enhancement was ~7.1 fold in comparison to Nocardia sp. CS682 without supplementation of any precursors. The overproduced compound was validated by mass spectrometry and nuclear magnetic resonance analyses. The novel glycosylated derivatives of purified nargenicin A1 were generated by efficient one-pot reaction systems in which the syntheses of uridine diphosphate (UDP)-α-D-glucose and UDP-α-D-2-deoxyglucose were modified and combined with glycosyltransferase (GT) from Bacillus licheniformis. Nargenicin A1 11-O-β- D-glucopyranoside, nargenicin A1 18-O-β-D-glucopyranoside, nargenicin A111 18-O-β-D- diglucopyranoside, and nargenicin 11-O-β-D-2-deoxyglucopyranoside were generated. Nargenicin A1 11-O-β-D-glucopyranoside was structurally elucidated by ultra-high performance liquid chromatography-photodiode array (UPLC-PDA) conjugated with high-resolution quantitative time-of-flight-electrospray ionization mass spectroscopy (HR-QTOF ESI-MS/MS), supported by one- and two-dimensional nuclear magnetic resonance studies, whereas other nargenicin A1 glycosides were characterized by UPLC-PDA and HR-QTOF ESI-MS/MS analyses. The overall conversion studies indicated that the one-pot synthesis system is a highly efficient strategy for production of glycosylated derivatives of compounds like macrolides as well. Furthermore, assessment of solubility indicated that there was enhanced solubility in the case of glycoside, although a substantial increase in activity was not observed.

Enzymatic Biosynthesis of Novel Resveratrol Glucoside and Glycoside Derivatives

A UDP glucosyltransferase from Bacillus licheniformis was overexpressed, purified, and incubated with nucleotide diphosphate (NDP) d- and l-sugars to produce glucose, galactose, 2-deoxyglucose, viosamine, rhamnose, and fucose sugar-conjugated resveratrol glycosides. Significantly higher (90%) bioconversion of resveratrol was achieved with α-d-glucose as the sugar donor to produce four different glucosides of resveratrol: resveratrol 3-O-β-d-glucoside, resveratrol 4'-O-β-d-glucoside, resveratrol 3,5-O-β-d-diglucoside, and resveratrol 3,5,4'-O-β-d-triglucoside. The conversion rates and numbers of products formed were found to vary with the other NDP sugar donors. Resveratrol 3-O-β-d-2-deoxyglucoside and resveratrol 3,5-O-β-d-di-2-deoxyglucoside were found to be produced using TDP-2-deoxyglucose as a donor; however, the monoglycosides resveratrol 4'-O-β-d-galactoside, resveratrol 4'-O-β-d-viosaminoside, resveratrol 3-O-β-l-rhamnoside, and resveratrol 3-O-β-l-fucoside were produced from the respective sugar donors. Altogether, 10 diverse glycoside derivatives of the medically important resveratrol were generated, demonstrating the capacity of YjiC to produce structurally diverse resveratrol glycosides.