Virstatin-Conjugated Gold Nanoparticle with Enhanced Antimicrobial Activity against the El Tor Biotype.

Because of the emergence of multidrug-resistant pathogenic bacteria, there is a growing interest for the development of an efficient alternative to antibiotics. Gold nanoparticles (AuNPs) are promising candidates due to their inherent non-toxicity and can be used as effective carriers of drugs. Cholera caused by Gram-negative is still a potential threat in many developing countries.

The gold nanoparticle reduces Vibrio cholerae pathogenesis by inhibition of biofilm formation and disruption of the production and structure of cholera toxin.

Formation of biofilm by Vibrio cholerae plays a crucial role in pathogenesis and transmission of cholera. Lower infective dose of the biofilm form of V. cholerae compared to the planktonic counterpart, and its antibiotic resistance, make it challenging to combat cholera.

The role of isoaspartate in fibrillation and its prevention by Protein-L-isoaspartyl methyltransferase.

Background: Isomerization of aspartate to isoaspartate (isoAsp) on aging causes protein damage and malfunction. Protein-L-isoaspartyl methyltransferase (PIMT) performs a neuroprotective role by repairing such residues. A hexapeptide, Val-Tyr-Pro-(isoAsp)-His-Ala (VA6), a substrate of PIMT, is shown to form fibrils, while the normal Asp-containing peptide does not.

The Sialic Acid-Dependent Nematocyst Discharge Process in Relation to Its Physical-Chemical Properties Is A Role Model for Nanomedical Diagnostic and Therapeutic Tools.

Formulas derived from theoretical physics provide important insights about the nematocyst discharge process of Cnidaria (Hydra, jellyfishes, box-jellyfishes and sea-anemones). Our model description of the fastest process in living nature raises and answers questions related to the material properties of the cell- and tubule-walls of nematocysts including their polysialic acid (polySia) dependent target function. Since a number of tumor-cells, especially brain-tumor cells such as neuroblastoma tissues carry the polysaccharide chain polySia in similar concentration as fish eggs or fish skin, it makes sense to use these findings for new diagnostic and therapeutic approaches in the field of nanomedicine.

The antibacterial and anticancer properties of zinc oxide coated iron oxide nanotextured composites.

Core-shell α-FeO-ZnO structures of different nanotextured morphology were synthesized through wet chemical routes using different solvents like ethanol, ethanolamine, water and acetaldehyde. Morphological tuning using different solvents resulted in the formation of different shapes, such as disc, spindle, rod and sphere (abbreviated as FZ-ND, FZ-NSP, FZ-NR and FZ-NS, respectively). Structural, morphological and compositional characterization of these nanoparticles (NPs) has been carried out.

The gamma ray detection threshold temperature of different superheated droplet detectors.

The response of superheated droplet detectors (SDD) loaded with four different active liquids, R-12 (CClF), R-114 (CClF), R-134a (CHF) and R-610 (CF) have been studied to obtain the gamma ray detection threshold temperature (T) of the respective detectors. A Cs gamma ray source is used for this study. To obtain T from the experimental data a phenomenological model has been used.

Modelling of growth kinetics of Vibrio cholerae in presence of gold nanoparticles: effect of size and morphology.

Emergence of multiple drug resistant strains of pathogenic bacteria calls for new initiatives to combat infectious diseases. Gold nanoparticles (AuNPs), because of their non-toxic nature and size/shape dependent optical properties, offer interesting possibility. Here we report the antibacterial efficacy of AuNPs of different size and shape (AuNS10, AuNS100 and AuNR10; the number indicating the diameter in nm; S stands for sphere and R for rod) against the classical (O395) and El Tor (N16961) biotypes of Vibrio cholerae, the etiological agent responsible for cholera.

Note: A new optical method for the detection of bubble nucleation in superheated droplet detector.

A superheated droplet detector (SDD) consists of a large number of micron-sized superheated liquid drops suspended in a gel medium. The vaporization of a superheated drop is associated with the emission of an acoustic signal. A novel optical method is developed for the detection of this acoustic signal.

Structure and function of Vibrio cholerae accessory cholera enterotoxin in presence of gold nanoparticles: Dependence on morphology.

Background: Accessory cholera enterotoxin (Ace) is a classical enterotoxin produced by Vibrio cholerae, the causative agent for cholera. Considering the crucial role of Ace in pathogenesis of cholera, we explored the modulation of structure/function of Ace using gold nanoparticles (AuNPs) of different size and shape - spherical (AuNS10 and AuNS100, the number indicating the diameter in nm) and rod (AuNR10).

Methods: Biophysical techniques have been used to find out structural modulation of Ace by AuNPs.

Crystal structure and activity of protein L-isoaspartyl-O-methyltransferase from Vibrio cholerae, and the effect of AdoHcy binding.

The repair enzyme Protein L-isoaspartyl-O-methyltransferase (PIMT) is widely distributed in various organisms. PIMT catalyzes S-adenosylmethionine (AdoMet) dependent methylation of abnormal L-isoaspartyl residues, formed by the deamidation of asparagines and isomerization of aspartates. We report the crystal structure of PIMT of Vibrio cholerae (VcPIMT), the aetiological agent for cholera, complexed with the demethylated cofactor S-adenosyl-L-homocysteine (AdoHcy) to 2.

Antibacterial effect of silver nanoparticles and the modeling of bacterial growth kinetics using a modified Gompertz model.

Background: An alternative to conventional antibiotics is needed to fight against emerging multiple drug resistant pathogenic bacteria. In this endeavor, the effect of silver nanoparticle (Ag-NP) has been studied quantitatively on two common pathogenic bacteria Escherichia coli and Staphylococcus aureus, and the growth curves were modeled.

Methods: The effect of Ag-NP on bacterial growth kinetics was studied by measuring the optical density, and was fitted by non-linear regression using the Logistic and modified Gompertz models.

The mathematics of dilution.

The major objection to homeopathic medicine is that the doses of medicine prescribed in some cases are too dilute for any active ingredient to be present. The medicines would hence be rendered inactive, necessitating novel explanations for the action. A further examination of dilution in the light of the Langmuir equation shows that homeopathic medicines may not be as dilute as a simplistic application of Avogadro's Principle suggests, due to surface effects.

Characterization of R-134a superheated droplet detector for neutron detection.

R-134a (C2H2F4) is a low cost, easily available and chlorine free refrigerant, which in its superheated state can be used as an efficient neutron detector. Due to its high solubility in water the R-134a based superheated droplet detectors (SDD) are usually very unstable unless the detector is fabricated using a suitable additive, which stabilizes the detector. The SDD is known to have superheated droplets distributed in a short-lived and in a relatively long-lived metastable states.

Interaction of virstatin with human serum albumin: spectroscopic analysis and molecular modeling.

Virstatin is a small molecule that inhibits Vibrio cholerae virulence regulation, the causative agent for cholera. Here we report the interaction of virstatin with human serum albumin (HSA) using various biophysical methods. The drug binding was monitored using different isomeric forms of HSA (N form ∼pH 7.

Ion mobility studies of electronically excited States of atomic transition metal cations: development of an ion mobility source for guided ion beam experiments.

The design of an ion mobility source developed to couple to a guided ion beam tandem mass spectrometer is presented. In these exploratory studies, metal ions are created continuously by electron ionization of the volatile hexacarbonyls of the three group 6 transition metals. These ions are focused into a linear hexapole ion trap, which collects the ions and then creates high intensity pulses of ions, avoiding excessive ion losses resulting from the low duty cycle of pulsed operation.