Flubendiamide induced genetic and cellular damages directly influence the life cycle of the oriental leaf worm, Spodoptera litura.

Indiscriminate uses of insecticide greatly damage the environment as well as non-target organisms. Thus, multiple levels of bioassays can help better management of our environment. Flubendiamide is a phthalic acid diamide insecticide that ceases the function of insect muscle leading to paralysis and death. Here, we aimed to explore the effects of Flubendiamide on the life cycle of Spodoptera litura vis-a-vis the mode of action. Fourth instar larvae of the same age (120 ± 2 h) and size were fed with different concentrations (20-80 µg/mL) of Flubendiamide for 12-72 h. We performed a pharmacokinetics study, different biochemical assays, p450, Ecdysone receptor (EcR) and other genes expression analyses by Real-Time PCR and gross damages by Dye exclusion assay and histopathology. Our results demonstrate that the mean concentration of Flubendiamide after 48 h is 9.907 µg/mL and (i) altered the molting, metamorphosis, and reproduction at 80 µg/mL (24 h) (ii) increases all oxidative stress parameters (ROS/RNS, MDA, 8OHdG), decreases oxidative defense mechanisms (SOD, CAT, GST) at 80 µg/mL (48 h) and p450 in a time and concentration-dependent manner, (iii) activates CncC/Maf apoptotic pathways at 80 µg/mL concentration at 24 h while the expression declined from 48 h onwards, (iii) downregulates the EcR expression in a time and concentration-dependent manner, which might be responsible for disturbed molting, metamorphosis, and reproduction, and (iv) increase the expression of apoptotic genes (Caspase 1, -3, and - 5), in time and concentration-dependent manner causing gross morphological and histological damages. In conclusion, indiscriminate use of this insecticide can affect the ecosystem and have the capacity to cause multiple hazardous effects on experimental organisms. Thus, it warrants further investigations to improve and optimize the integrated pest management packages, including Flubendiamide for better management.

Immobilization of GOx Enzyme on SiO2-Coated Ni-Co Ferrite Nanocomposites as Magnetic Support and Their Antimicrobial and Photocatalytic Activities.

The present study used a sol-gel auto-combustion approach to make silica (SiO2)-coated Ni-Co ferrite nanocomposites that would be used as a platform for enzyme immobilization. Using glutaraldehyde as a coupling agent, glucose oxidase (GOx) was covalently immobilized on this magnetic substrate. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM), and fourier transform infrared spectroscopy (FTIR) was used to determine the structural analysis and morphology of Ni-Co ferrite/SiO2 nanocomposites. FTIR spectra confirmed the binding of GOx to Ni-Co ferrite/SiO2 nanocomposites, with a loading efficiency of around 85%. At alkaline pH and higher temperature, the immobilized GOx enzyme exhibited increased catalytic activity. After 10 times of reuses, it still had 69% catalytic activity. Overall, the immobilized GOx displayed higher operational stability than the free enzyme under severe circumstances and was easily recovered by magnetic separation. With increased doping concentration of the nanocomposites, the photocatalytic activity was assessed using a degradation process in the presence of methylene blue dye under UV light irradiation, which revealed that the surface area of the nanocomposites with increased doping concentration played a significant role in improving photocatalytic activity. The antibacterial activity of Ni-Co ferrite/SiO2 nanocomposites was assessed using the agar well diffusion method against Escherichia coli, a gram-negative bacteria (ATCC 25922). Consequently, it was revealed that doping of Ni2+ and Co2+ in Fe2O4/SiO2 nanocomposites at varied concentrations improved their antibacterial properties.

Aorta smooth muscle-on-a-chip reveals impaired mitochondrial dynamics as a therapeutic target for aortic aneurysm in bicuspid aortic valve disease.

Background: Bicuspid aortic valve (BAV) is the most common congenital cardiovascular disease in general population and is frequently associated with the development of thoracic aortic aneurysm (TAA). There is no effective strategy to intervene with TAA progression due to an incomplete understanding of the pathogenesis. Insufficiency of NOTCH1 expression is highly related to BAV-TAA, but the underlying mechanism remains to be clarified. Methods: A comparative proteomics analysis was used to explore the biological differences between non-diseased and BAV-TAA aortic tissues. A microfluidics-based aorta smooth muscle-on-a-chip model was constructed to evaluate the effect of NOTCH1 deficiency on contractile phenotype and mitochondrial dynamics of human aortic smooth muscle cells (HAoSMCs). Results: Protein analyses of human aortic tissues showed the insufficient expression of NOTCH1 and impaired mitochondrial dynamics in BAV-TAA. HAoSMCs with NOTCH1-knockdown exhibited reduced contractile phenotype and were accompanied by attenuated mitochondrial fusion. Furthermore, we identified that mitochondrial fusion activators (leflunomide and teriflunomide) or mitochondrial fission inhibitor (Mdivi-1) partially rescued the disorders of mitochondrial dynamics in HAoSMCs derived from BAV-TAA patients. Conclusions: The aorta smooth muscle-on-a-chip model simulates the human pathophysiological parameters of aorta biomechanics and provides a platform for molecular mechanism studies of aortic disease and related drug screening. This aorta smooth muscle-on-a-chip model and human tissue proteomic analysis revealed that impaired mitochondrial dynamics could be a potential therapeutic target for BAV-TAA. Funding: National Key R and D Program of China, National Natural Science Foundation of China, Shanghai Municipal Science and Technology Major Project, Shanghai Science and Technology Commission, and Shanghai Municipal Education Commission.

To function properly, the heart must remain a one-way system, pumping out oxygenated blood into the aorta ­ the largest artery in the body ­ so it can be distributed across the organism. The aortic valve, which sits at the entrance of the aorta, is a key component of this system. Its three flaps (or 'cusps') are pushed open when the blood exits the heart, and they shut tightly so it does not flow back in the incorrect direction. Nearly 1.4% of people around the world are born with 'bicuspid' aortic valves that only have two flaps. These valves may harden or become leaky, forcing the heart to work harder. This defect is also associated with bulges on the aorta which progressively weaken the artery, sometimes causing it to rupture. Open-heart surgery is currently the only way to treat these bulges (or 'aneurysms'), as no drug exists that could slow down disease progression. This is partly because the biological processes involved in the aneurysms worsening and bursting open is unclear. Recent studies have highlighted that many individuals with bicuspid aortic valves also have lower levels of a protein known as NOTCH1, which plays a key signalling role for cells. Problems in the mitochondria ­ the structures that power up a cell ­ are also observed. However, it is not known how these findings are connected or linked with the aneurysms developing. To answer this question, Abudupataer et al. analyzed the proteins present in diseased and healthy aortic muscle cells, confirming a lower production of NOTCH1 and impaired mitochondria in diseased tissues. They also created an 'aorta-on-a-chip' model where aortic muscle cells were grown in the laboratory under conditions resembling those found in the body ­ including the rhythmic strain that the aorta is under because of the heart beating. Abudupataer et al. then reduced NOTCH1 levels in healthy samples, which made the muscle tissue less able to contract and reduced the activity of the mitochondria. Applying drugs that tweak mitochondrial activity helped tissues from patients with bicuspid aortic valves to work better. These compounds could potentially benefit individuals with deficient aortic valves, but experiments in animals and clinical trials would be needed first to confirm the results and assess safety. The aorta-on-a-chip model developed by Abudupataer et al. also provides a platform to screen for drugs and examine the molecular mechanisms at play in aortic diseases.

Rapid prototyping of PDMS microdevices viaµPLAT on nonplanar surfaces with flexible hollow-out mask.

A major goal of polydimethylsiloxane (PDMS) microfabrication is to develop a simple and inexpensive method for rapid fabrication. Despite the recent advancements in this field, facile PDMS microfabrication on non-planar surfaces remains elusive. Here we report a facile method for rapid prototyping of PDMS microdevices viaµPLAT (microscale plasma-activated templating) on non-planar surfaces through micropatterning of hydrophilic/hydrophobic (HL/HB) interface by flexible polyvinyl chloride (PVC) hollow-out mask. This mask can be easily prepared with flexible PVC film through a cutting crafter and applied as pattern definer during the plasma treatment for microscale HL/HB interface formation on different substrates. The whole process requires low inputs in terms of time as well as toxic chemicals. Inspired by liquid molding, we demonstrated its use for rapid prototyping of PDMS microstructures. Following the proof-of-concept study, we also demonstrated the use of the flexible hollow-out mask to facilitate cell patterning on curved substrates, which is difficult to realize with conventional methods. Collectively, our work utilizes flexible and foldable PVC film as mask materials for facile microscale HL non-planar surface modification to establish a useful tool for PDMS prototyping and cell patterning.

Interaction of thiamethoxam with DNA: Hazardous effect on biochemical and biological parameters of the exposed organism.

In the present scenario, insecticides/pesticides are used intensively to control the various insect pests. Indiscriminate use of these insecticides/pesticides affects the structure and function of the ecosystem. In this context, a thorough toxicological study of each insecticide/pesticide is a must to understand the hazardous effect of these chemicals on the target and non-target organisms. The present study was aimed to understand the hazardous effect of thiamethoxam against the Spodoptera litura. Different concentrations (20-80 µg/mL) of thiamethoxam were prepared, and fourth instar larvae of S. litura were allowed to feed for 12-72 h. We first examined the interaction of thiamethoxam with DNA. Next, treated and non-treated larvae were assessed for different biological parameters such as mortality, emergence, fecundity, fertility, longevities, and biochemical parameters. Our result showed that thiamethoxam directly interacts with the DNA and significantly influenced the different biological and biochemical parameters of exposed the organisms. We observed a significant change in stress enzymes such as SOD, CAT, and GST. A similar observation was also made with the oxidative marker for lipid damage, MDA and DNA damage, 8-OHdG, respectively. In conclusion, our results suggest that improper use of synthetic chemical insecticides influenced both biological and biochemical parameters through oxidative stress and probably damage the genetic material.

Fractal SERS nanoprobes for multiplexed quantitative gene profiling.

Quantitative analysis is critical for biological and chemical sensing applications, yet still remains a great challenge in surface-enhanced Raman spectroscopy (SERS). Here we report the development of a novel fractal SERS nanoprobe with robust internal calibration standard and high multiplexing capability for ultrasensitive detection of DNA and microRNA. This fractal SERS nanoprobe consists of a solid Au core of ~13 nm, an inner hollow gap of ~1 nm, and a stellate outer shell. The inner hollow gap enables the embedding of Raman tags that can serve as a self-calibrating internal standard to effectively correct the fluctuations of samples and measuring conditions. The outer shell morphology is highly tunable, which provides distinct SERS enhancement and enables a reproducible quantitative measurement of nucleic acids down to femtomolar level. In addition, the flexibility of encoding crosstalk-free Raman tag molecules makes such SERS sensor particularly attractive for multiplexed bioassays. This technique is simple, reliable, and of wide applicability to various genomic screening and diagnostic applications.

A Self-Calibrating Surface-Enhanced Raman Scattering-Active System for Bacterial Phenotype Detection.

Pathogen detection is of significant importance in human health and safety due to the high morbidity and mortality induced by bacterial infections. Therefore, the development of rapid, sensitive, and selective methods for the discrimination of pathogens is the key to improve the patient survival rates. In this work, we develop a new self-calibrating surface-enhanced Raman scattering (SERS)-based sensor that enables sensitive and reproducible pathogen detection in practical samples. The assay makes use of gold nanoflowers (AuNFs) consisting of three components: a solid Au core of ∼15 nm, a hollow gap of ∼1 nm, and a flower-like Au shell. We have demonstrated that the sensitive and quantitative analysis of biomolecules can be achieved by the target-dependent, sequence-specific DNA hybridization assembly between AuNFs with a built-in internal standard. We further demonstrate that this kind of reliable SERS sensor is able to distinguish different bacteria with sensitivity down to single bacterium. We expect that the established quantitative SERS technique could provide a promising tool for widespread applications in biomedical research and clinical diagnostics.

Arsenic inhibits human salivary aldehyde dehydrogenase: Mechanism and a population-based study.

Human salivary aldehyde dehydrogenase (hsALDH) is an important detoxifying enzyme and maintains oral health. Subjects with low hsALDH activity are at a risk of developing oral cancers. Arsenic (As) toxicity causes many health problems in humans. The objective of this population-based study was to correlate As contamination and hence low hsALDH activity with high incidence of cancer cases in Bareilly district of India. Here, it was observed that As inhibited hsALDH (IC50 value: 33.5 ± 2.5 µM), and the mechanism of inhibition was mixed type (in between competitive and non-competitive). Binding of As to hsALDH changed the conformation of the enzyme. A static quenching mechanism was observed between the enzyme and As with a binding constant (Kb) of 9.77 × 104 M-1. There is one binding site for As on hsALDH molecule. Further, the activity of hsALDH in volunteers living in regions of higher As levels in drinking water (Bahroli and Mirganj village of Bareilly district, India), and those living in region having safe levels of As (Aligarh city, India) was determined. The As level in the saliva samples of the volunteers was determined by inductively coupled plasma mass spectroscopy (ICP-MS). Low hsALDH activity was found in volunteers living in the region of higher As levels. The activity of hsALDH and As concentration in the saliva was found to be negatively correlated (r = - 0.427, p < 0.0001). Therefore, we speculate that the high incidence of cancer cases reported in Bareilly district may be due to higher As contamination.

Immobilization of ß-galactosidase on tannic acid stabilized silver nanoparticles: A safer way towards its industrial application.

In this study, ß-galactosidase has been immobilized on tannic acid stabilized silver nanoparticles (AgNPs). Tannic acid is a phytochemical and it is advantageous to use it as a linker molecule for immobilization because of its antidiarrheal and antimicrobial properties, and very low toxicity. AgNPs with immobilized ß-galactosidase were characterized for particle size and catalytic properties. The AgNPs consisted of almost monodispersed particles of average diameter of ∼20 nm. ß-galactosidase immobilized on tannic acid stabilized AgNPs (83.6% Immobilization yield) exhibited good activity with a high enzyme to carrier ratio as compared to the previous reports. Immobilization did not affect the optimum pH (pH 4.5) of the enzyme, however it retained greater fraction of activity in both alkaline and acidic pH range. The immobilized enzyme exhibited greater fraction of activity at higher temperatures as compared to the soluble enzyme, and its optimum temperature increased by 5 °C. The immobilized enzyme retained almost 60% of its activity after 10th successive use. The immobilized enzyme hydrolyzed 258 and 474 µM lactose from 1% lactose and from milk lactose, respectively, whereas the soluble enzyme hydrolyzed 235 and 424 µM lactose from 1% lactose and from milk lactose, respectively. Excellent activity and stability of ß-galactosidase immobilized on AgNPs provides a cost-effective industrial application of this enzyme. ß-galactosidase immobilized on tannic acid stabilized AgNPs are free from toxicity hazards of the linker molecules. Hence, it may find constructive enzyme based applications in food technology.

Correlation between the Activity of Aldehyde Dehydrogenase and Oxidative Stress Markers in the Saliva of Diabetic Patients.

BACKGROUND: Reactive aldehydes are involved in diseases associated with oxidative stress, including diabetes. Human salivary aldehyde dehydrogenase (hsALDH) presumably protects us from many toxic ingredient/contaminant aldehydes present in food. OBJECTIVE: This study aimed to probe the activity of hsALDH in patients with diabetes and than to correlate it with various oxidative stress markers in the saliva. METHODS: The saliva samples were collected from total 161 diabetic patients from Rajiv Gandhi Centre for Diabetes, Jawaharlal Nehru Medical College (JNMC), AMU, Aligarh, (India). HsALDH activity and markers of oxidative stress [8-hydroxydeoxyguanosine (8-OHDG), malondialdehyde (MDA) and advanced glycation end products (AGEs)] were measured in the saliva samples. RESULTS: Patients with early stage of diabetes had higher activity of hsALDH when compared with the control group. As the history of diabetes increases, the activity of the enzyme decreases and also higher oxidative stress markers (8-OHDG, MDA and AGEs) are detected in the saliva samples. Negative significant correlation between hsALDH activity and oxidative stress markers were observed (p <0.0001). CONCLUSION: The activity of hsALDH increases in early stages of diabetes most probably to counter the increased oxidative stress associated with diabetes. However, in later stages of diabetes, the activity of the enzyme decreases, possibly due to its inactivation resulting from glycation.

Hydrogel Bioink with Multilayered Interfaces Improves Dispersibility of Encapsulated Cells in Extrusion Bioprinting.

One of the challenges for extrusion bioprinting using low-viscosity bioinks is the fast gravity-driven sedimentation of cells. Cells in a hydrogel bioink that features low viscosity tend to settle to the bottom of the bioink reservoir, and as such, their bioprintability is hindered by association with the inhomogeneous cellularized structures that are deposited. This is particularly true in cases where longer periods are required to print complex or larger tissue constructs. Increasing the bioink's viscosity efficiently retards sedimentation but gives rise to cell membranolysis or functional disruption due to increased shear stress on the cells during the extrusion process. Inspired by the rainbow cocktail, we report the development of a multilayered modification strategy for gelatin methacryloyl (GelMA) bioink to manipulate multiple liquid interfaces, providing interfacial retention to retard cell sedimentation in the bioink reservoir. Indeed, the interfacial tension in our layer-by-layer bioink system, characterized by the pendant drop method, was found to be exponentially higher than the sedimental pull (ΔGravity-Buoyancy = ∼10-9 N) of cells, indicating that the interfacial retention is crucial for preventing cell sedimentation across the adjacent layers. It was demonstrated that the encapsulated cells displayed better dispersibility in constructs bioprinted using the multilayered GelMA bioink system than that of pristine GelMA where the index of homogeneity of the cell distribution in the multilayered bioink was 4 times that of the latter.

pH-Operated Triplex DNA Device on MoS2 Nanosheets.

We report a triplex-based DNA device coupled with molybdenum disulfide (MoS2) nanosheets for use as a pH-sensing platform. The device transitions from a duplex state at pH 8 to a triplex state at pH 5. The interaction of the device with MoS2 nanosheets in the two states is read out as a fluorescence signal from a pH-insensitive dye attached to the device. We characterized the operation of the DNA device on MoS2 nanosheets, analyzed the pH response, and tested the reversibility of the system. Our strategy can lead to the creation of a suite of biosensors where the sensing element is a triplex DNA device and the signal response is modulated by inorganic nanomaterials.

Hazardous sub-cellular effects of Fipronil directly influence the organismal parameters of Spodoptera litura.

Indiscriminate use of insecticides/pesticides affects the structure and function of the ecosystems. The present study was aimed to investigate the toxic potential of Fipronil (a second generation phenylpyrazole) using Spodoptera litura larvae (Lepidoptera: Noctuidae) as an experimental model. Commercial grade of Fipronil, an insecticide was fed (20-80 mg/L) to the 4th instar larvae of S. litura for 12-72 h and examined different molecular, biochemical and organismal parameters. We observed a significant dose- and time-dependent changes in the biochemical parameters such as Superoxide dismutase (SOD), Glutathione-S-transferase (GST), Catalase (CAT), level of 8-hydroxy 2'-deoxyguanosine (8-OHdG) and Thiobarbituric Acid Reactive Substances (TBARS) [Malondialdehyde (MDA) equivalent] in the exposed larvae. We also observed that Fipronil interacts with DNA. Next, we examined the influence of sub-cellular damages at the organismal level. The alterations in the parameter such as the delayed emergence of larvae, reduced fecundity, fertility and increased rate of malformation in pupae and adults indicate the sub-organismal damages influence at the organismal level. The findings of the present study suggest that discriminatory non-scientific use of insecticide/pesticide might influence the population dynamics of insects and in large ecosystem too and needs further thorough investigations.

In vitro DNA binding studies of therapeutic and prophylactic drug citral.

The study of drug-DNA interactions is of great importance, as it paves the way towards the design of better therapeutic agents. Here, the interaction of DNA with a therapeutic and prophylactic drug citral has been studied. We have attempted to ascertain the mode of binding of citral with calf thymus DNA (Ct-DNA) through various biophysical techniques. Analysis of the UV-visible absorbance spectra and fluorescence spectra indicated the formation of a complex between citral and Ct-DNA. Competitive binding assays with ethidium bromide (EB), acridine orange (AO) and Hoechst 33258 reflected that citral possibly intercalates within the Ct-DNA. These observations were further confirmed by circular dichroism (CD) spectral analysis, viscosity measurements, DNA melting and molecular docking studies. This study is expected to contribute to a better understanding of molecular mechanisms of citral, and design of new drugs in the future.

Hybrid pharmacophore approach for bio-relevant di-imines based homobimetallic complexes incorporating functionalized dicarboxylates as co-ligands: Synthesis, spectral and structural activity dependent biological insights (in-vitro DNA and HSA binding, antioxidant and cytotoxicity).

Synthesis of bio-efficient homobimetallic complexes, [Cu2(L1)2(dipic)](NO3)2.3H2O (1), [Zn2(L1)2(dipic)](NO3)2.4H2O (2), [Cu2(L2)2(oxa)](NO3)2.4H2O (3) and [Zn2(L2)2(oxa)] (NO3)2.5H2O (4) was carried out using Schiff bases [(N1E,N2E)-N1,N2-bis(5-chlorothiophen-2-ylmethylene)-4-chlorobenzene-1,2-diamine; L1] and [(N1E,N2E)-N1,N2-bis(5-chlorofuran-2-ylmethylene)-4-chlorobenzene-1,2-diamine; L2] as main ligands and dicarboxylate moieties of 2,6-pyridine dicarboxylic acid (H2-dipic) and oxalic acid (H2-oxa) as co-ligands, respectively in order to apprehend their structure activity relationships on the basis of pharmacophore hybrid approach. The stoichiometry, geometry, thermal stability, morphology and crystallite size of the compounds were inferred by analytical, spectral (FT-IR, 1H NMR and 13C NMR and Mass), thermal (TGA/DTA), SEM and XRD studies. In-vitro DNA and HSA binding profiles of complexes were analysed by different biophysical measurements. The absorption study divulged that the observed alterations in the physico-chemical properties of complexes upon binding with DNA connoted their intercalative binding mode while fluorescence quenching mechanism was quantified by using Stern Volmer constant (KSV); 1.73×104 (1), 1.47×104 (2), 5.65×103 (3) and 3.60×103M-1 (4) which discerned that hybrid pharmacophore active metal complexes (1 and 2) exhibited efficient quenching effect with Ct-DNA in comparison to complexes (3 and 4) due to greater planarity and extent of conjugation (π-π interactions). The intercalative binding mode of complexes is further supported by competitive displacement assay by using fluorogenic dyes (EtBr and Hoechst 33258). The results of HSA fluorescence study divulged static quenching of the complexes (1-4) with KSV values of 7.24×104 (1), 6.03×104 (2), 5.06×104 (3) and 2.85×104 (4) while Kb values; 1.16×105 (1), 2.01×104 (2), 5.84×103 (3) and 8.60×102 (4) suggested them potent avid binder of HSA. Additionally, comparative estimation of scavenging properties using DPPH, superoxide(O2.-), hydroxyl (OH-) and ABTS method and in-vitro cytotoxicity against different cell lines (MCF-7, HeLa and Hep G2) brought out distinct biopotency of complexes due to diverse structural features and chelation effect.

Colorimetric method for the detection of melamine using in-situ formed silver nanoparticles via tannic acid.

Melamine toxicity has recently attracted worldwide attention as it causes renal failure and the death of humans and animals. Therefore, developing a simple, fast and sensitive method for the routine detection of melamine is the need of the hour. Herein, we have developed a selective colorimetric method for the detection of melamine in milk samples based upon in-situ formation of silver nanoparticles (AgNPs) via tannic acid. The AgNPs thus formed were characterized by UV-Visible spectrophotometer, transmission electron microscope (TEM), zetasizer and dynamic light scattering (DLS). The AgNPs were used to detect melamine under in vitro condition and in raw milk spiked with melamine. Under optimal conditions, melamine could be selectively detected in vitro within the concentration range of 0.05-1.4µM with a limit of detection (LOD) of 0.01µM, which is lower than the strictest melamine safety requirement of 1ppm. In spiked raw milk, the recovery percentage range was 99.5-106.5% for liquid milk and 98.5-105.5% for powdered milk. The present method shows extreme selectivity with no significant interference with other substances like urea, glucose, glycine, ascorbic acid etc. This assay method does not utilize organic cosolvents, enzymatic reactions, light sensitive dye molecules and sophisticated instrumentation, thereby overcoming some of the limitations of the other conventional methods.

In vitro activity and stability of pure human salivary aldehyde dehydrogenase.

Human salivary aldehyde dehydrogenase (HsALDH) appears to be the first line of defence against toxic aldehydes contained in exogenous sources and is important for maintaining healthy oral cavity and protection from oral cancer. Here, the activity and stability of purified hsALDH has been determined under different conditions such as temperature, in presence of denaturants [Urea and guanidine hydrochloride (GnHCl)] and in the presence of salt (NaCl). The pure enzyme exhibited low stability when stored at room temperature (25°C) as well as at low temperature (4°C). 10% glycerol significantly improved its storage stability, particularly at 25°C. HsALDH was observed to have very low thermal stability. At higher temperatures, the enzyme gets unfolded and loses its activity quite rapidly. Further, the enzyme is unstable in the presence of denaturants like urea and GnHCl which unfold the enzyme. Salt (NaCl) has an activating effect on the enzyme, resulting from perhaps due to some conformational changes in the enzyme which facilitates the catalysis process. HsALDH proved to be a labile enzyme under in vitro conditions and certain additives like glycerol and NaCl can improve the activity/stability of the enzyme. Hence, a stabilizing agent is required to use the enzyme in in vitro studies.

Activation of Human Salivary Aldehyde Dehydrogenase by Sulforaphane: Mechanism and Significance.

Cruciferous vegetables contain the bio-active compound sulforaphane (SF) which has been reported to protect individuals against various diseases by a number of mechanisms, including activation of the phase II detoxification enzymes. In this study, we show that the extracts of five cruciferous vegetables that we commonly consume and SF activate human salivary aldehyde dehydrogenase (hsALDH), which is a very important detoxifying enzyme in the mouth. Maximum activation was observed at 1 µg/ml of cabbage extract with 2.6 fold increase in the activity. There was a ~1.9 fold increase in the activity of hsALDH at SF concentration of ≥ 100 nM. The concentration of SF at half the maximum response (EC50 value) was determined to be 52 ± 2 nM. There was an increase in the Vmax and a decrease in the Km of the enzyme in the presence of SF. Hence, SF interacts with the enzyme and increases its affinity for the substrate. UV absorbance, fluorescence and CD studies revealed that SF binds to hsALDH and does not disrupt its native structure. SF binds with the enzyme with a binding constant of 1.23 x 107 M-1. There is one binding site on hsALDH for SF, and the thermodynamic parameters indicate the formation of a spontaneous strong complex between the two. Molecular docking analysis depicted that SF fits into the active site of ALDH3A1, and facilitates the catalytic mechanism of the enzyme. SF being an antioxidant, is very likely to protect the catalytic Cys 243 residue from oxidation, which leads to the increase in the catalytic efficiency and hence the activation of the enzyme. Further, hsALDH which is virtually inactive towards acetaldehyde exhibited significant activity towards it in the presence of SF. It is therefore very likely that consumption of large quantities of cruciferous vegetables or SF supplements, through their activating effect on hsALDH can protect individuals who are alcohol intolerant against acetaldehyde toxicity and also lower the risk of oral cancer development.

Pharmacological evaluation of poly(3-methylthiophene) and its titanium(IV)phosphate nanocomposite: DNA interaction, molecular docking, and cytotoxic activity.

Cancer and pathogenic microbial diseases have terribly affected human health over a longer period of time. In response to the increasing casualties due to cancer and microbial diseases, unique poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate composite were prepared via in-situ oxidative chemical polymerization in this work. The poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate composite were well characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. DNA binding studies by UV-Visible and fluorescence spectroscopic investigations indicated strong binding affinities of poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite; leading to structural damage of DNA. Poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite showed stronger interactions with DNA as compared to poly(3-methylthiophene) and from dye displacement assay it was confirmed that mode of binding of both the formulations was intercalative. The antimicrobial screening revealed that polymer and its composite displayed stronger antibacterial effects than ampicillin against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhimurium. Besides, the poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite showed dose dependent effects towards estrogen receptor positive breast cancer (MCF-7) and estrogen receptor negative breast cancer (MDA-MB-231) cell lines; with poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite showing better activities against both cell lines. In all in-vitro biological investigations, poly(3-methylthiophene)-titanium(IV)phosphate composite showed superior properties to that of the pure poly(3-methylthiophene), which encouraged us to suggest its potential as future therapeutic gear in drug delivery and other allied fields.

Molecular hybridization approach of bio-potent CuII/ZnII complexes derived from N, O donor bidentate imine scaffolds: Synthesis, spectral, human serum albumin binding, antioxidant and antibacterial studies.

Novel bio-relevant monometallic Schiff base complexes of the type, [Cu(L1)2] (1), [Zn(L1)2]·2H2O (2), [Cu(L2)2]·2H2O (3) and [Zn(L2)2]·H2O (4) [L1(E)-3-(((3-chloro-4-hydroxyphenyl)imino)methyl)naphthalen-2-ol and L2(E)-2-chloro-4-((1-(5-chloro-2-hydroxyphenyl)ethylidene)amino)phenol] were synthesized and characterized. A comparative account of analytical, spectroscopic (FT-IR, 1H and 13C NMR, Mass, UV-vis and EPR), thermal (TGA/DTA), XRD and SEM studies revealed a correlation between the structure and function of these biologically active molecular entities. HSA (Human serum albumin) binding profiles of the metal complexes (1-4) were monitored using biophysical techniques viz., absorbance, fluorescence, circular dichromism (CD) and foster resonance energy transfer (FRET). The intrinsic binding constant (Kb) demonstrated substantial binding propensity of L1 linked complexes (1 and 2) in comparison to L2 complexes (3 and 4) suggesting L1 to be more bio-active pharmacophore due to higher planarity and conjugation as compared to L2 ligand. The outcome of fluorescence study revealed static quenching mechanism on the basis of the quenching of HSA by the complexes (1-4). However, modifications in the secondary structure of HSA by complexes (1-4) inferred via CD measurements which revealed the enhancement of α-helicity (67.47% to 69.20%) with the preference order of 1>2>3>4. Furthermore, in-vitro antibacterial study against different bacteria and antioxidant activities against DPPH and superoxide radical (O2-) at variable concentrations outspread discernible bio-potencies of the metal complexes as compared to free ligand scaffolds due to the chelation effect.