Usefulness of Organic Acid Produced by Exiguobacterium sp. 12/1 on Neutralization of Alkaline Wastewater

The aim of this study was to investigate the role of organic acids produced by Exiguobacterium sp. strain 12/1 (DSM 21148) in neutralization of alkaline wastewater emanated from beverage industry. This bacterium is known to be able to grow in medium of pH as high as pH 12.0 and to neutralize alkaline industrial wastewater from pH 12.0 to pH 7.5. The initial investigation on the type of functional groups present in medium, carried out using FT-IR spectroscopy, revealed the presence of peaks corresponding to carbonyl group and hydroxyl group, suggesting the release of carboxylic acid or related metabolic product(s). The identification of specific carboxylic group, carried out using RP-HPLC, revealed the presence of a single peak in the culture supernatant with retention time most similar to formic acid. The concentration of acid produced on different carbon sources was studied as a function of time. Although acid was present in same final concentration, the rate of acid production was highest in case of medium supplemented with sucrose followed by fructose and glucose. The knowledge of metabolic products of the bacterium can be considered as a first step towards realization of its potential for large-scale bioremediation of alkaline wastewater from beverage industry

Proteome maps of flood-tolerant FR 13A and flood-sensitive IR 54 rice types depicting proteins associated with O<SUB>2</SUB>-deprivation stress and recovery regimes

Rice crop, particularly in lowland ecosystem, is severely affected by flooding stress. To genetically engineer rice with improved flooding tolerance, it is important to gain an understanding of the proteins that constitute its flooding-stress response. A major component of the flooding stress is a decline in availability of O2. Proteomics approach is a powerful tool for analysing global changes in protein profiles. We have constructed proteome maps of flood-sensitive IR 54 and floodtolerant FR 13A rice types corresponding to several time points during their response to O2 deprivation stress. Several up- and down-regulated proteins have been identified by 1D and 2D protein gel electrophoresis followed by silver staining. Based on peptide sequence analysis, we indicate that sucrose synthase, glyceraldehyde 3-phosphate dehydrogenase, UDP-glucose- 6-dehydrogenase and asparagine synthetase are implicated in rice flooding-stress response

Inhibition of Protein Aggregation: Supramolecular Assemblies of Arginine Hold the Key

BACKGROUND: Aggregation of unfolded proteins occurs mainly through the exposed hydrophobic surfaces. Any mechanism of inhibition of this aggregation should explain the prevention of these hydrophobic interactions. Though arginine is prevalently used as an aggregation suppressor, its mechanism of action is not clearly understood. We propose a mechanism based on the hydrophobic interactions of arginine. METHODOLOGY: We have analyzed arginine solution for its hydrotropic effect by pyrene solubility and the presence of hydrophobic environment by 1-anilino-8-naphthalene sulfonic acid fluorescence. Mass spectroscopic analyses show that arginine forms molecular clusters in the gas phase and the cluster composition is dependent on the solution conditions. Light scattering studies indicate that arginine exists as clusters in solution. In the presence of arginine, the reverse phase chromatographic elution profile of Alzheimer's amyloid beta 1-42 (Abeta(1-42)) peptide is modified. Changes in the hydrodynamic volume of Abeta(1-42) in the presence of arginine measured by size exclusion chromatography show that arginine binds to Abeta(1-42). Arginine increases the solubility of Abeta(1-42) peptide in aqueous medium. It decreases the aggregation of Abeta(1-42) as observed by atomic force microscopy. CONCLUSIONS: Based on our experimental results we propose that molecular clusters of arginine in aqueous solutions display a hydrophobic surface by the alignment of its three methylene groups. The hydrophobic surfaces present on the proteins interact with the hydrophobic surface presented by the arginine clusters. The masking of hydrophobic surface inhibits protein-protein aggregation. This mechanism is also responsible for the hydrotropic effect of arginine on various compounds. It is also explained why other amino acids fail to inhibit the protein aggregation

Nanoparticle formation from poly(acrylic acid) and oppositely charged peptides

Cationic peptides self assemble upon interacting with sodium salt of oppositely charged polymer, poly(acrylic acid), PAA, giving rise to water-soluble nanoparticles at very low concentration (0.1 mM of PAA). The morphology of these kinds of nanoparticles is mainly governed by the composition of the complexes, which can be expressed as Z_+/−, i.e., the ratio of positively charged units to the concentration of anionic units of the polymers present in the system. In the present study, at lower Z_+/−, the particles are elongated in shape but adopt spherical shape of 75–100 nm in diameter at higher Z_+/− values. We propose that the nanoparticles containing cationic peptides obtained by this methodology can serve as delivery system to enhance the antinociception effect of the chimeric peptide with previously administered doses

Role of histidine interruption in mitigating the pathological effects of long polyglutamine stretches in SCA1: A molecular approach

Polyglutamine expansions, leading to aggregation, have been implicated in various neurodegenerative disorders. The range of repeats observed in normal individuals in most of these diseases is 19–36, whereas mutant proteins carry 40–81 repeats. In one such disorder, spinocerebellar ataxia (SCA1), it has been reported that certain individuals with expanded polyglutamine repeats in the disease range (Q12HQHQ12HQHQ14/15) but with histidine interruptions were found to be phenotypically normal. To establish the role of histidine, a comparative study of conformational properties of model peptide sequences with (Q12HQHQ12HQHQ12) and without (Q42) interruptions is presented here. Q12HQHQ12HQHQ12 displays greater solubility and lesser aggregation propensity compared to uninterrupted Q42 as well as much shorter Q22. The solvent and temperature-driven conformational transitions (β structure ↔ random coil → α helix) displayed by these model polyQ stretches is also discussed in the present report. The study strengthens our earlier hypothesis of the importance of histidine interruptions in mitigating the pathogenicity of expanded polyglutamine tract at the SCA1 locus. The relatively lower propensity for aggregation observed in case of histidine interrupted stretches even in the disease range suggests that at a very low concentration, the protein aggregation in normal cells, is possibly not initiated at all or the disease onset is significantly delayed. Our present study also reveals that besides histidine interruption, proline interruption in polyglutamine stretches can lower their aggregation propensity

YFa and analogs: Investigation of opioid receptors in smooth muscle contraction

AIM: To study the pharmacological profile and inhibition of smooth muscle contraction by YFa and its analogs in conjunction with their receptor selectivity

Comparative mode of action of novel hybrid peptide CS-1a and its rearranged amphipathic analogue CS-2a

Cell selective, naturally occurring, host defence cationic peptides present a good template for the design of novel peptides with the aim of achieving a short length with improved antimicrobial potency and selectivity. A novel, short peptide CS-1a (14 residues) was derived using a sequence hybridization approach on sarcotoxin I (39 residues) and cecropin B (35 residues). The sequence of CS-1a was rearranged to enhance amphipathicity with the help of a Schiffer–Edmundson diagram to obtain CS-2a. Both peptides showed good antibacterial activity in the concentration range 4–16 &#956;g·mL⁻¹ against susceptible as well as drug-resistant bacterial strains, including the clinically relevant pathogens Acenatobacter sp. and methicillin-resistant Staphylococcus aureus. The major thrust of these peptides is their nonhaemolytic activity against human red blood cells up to a high concentration of 512 &#956;g·mL⁻¹. Compared to CS-1a, amphipathic peptide CS-2a showed a more pronounced α-helical conformation, along with a better membrane insertion depth in bacterial mimic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dipalmitoyl-sn-glycero-3-phospho-(1&#x2032;-rac-glycerol) small unilamellar vesicles. With equivalent lipid-binding affinity, the two peptides assumed different pathways of membrane disruption, as demonstrated by calcein leakage and the results of transmission electron microscopy on model bacterial mimic large unilamellar vesicles. Extending the work from model membranes to intact Escherichia coli cells, differences in membrane perturbation were visible in microscopic images of peptide-treated E. coli. The present study describes two novel short peptides with potent activity, cell selectivity and divergent modes of action that will aid in the future design of peptides with better therapeutic potential

Chimeric peptide of met-enkephalin and FMRFa: effect of chlorination on conformation and analgesia

In our previous study YFa (YGGFMKKKFMRFa), a chimeric peptide of met-enkephalin and FMRFa, not only produced analgesia but also did not let the tolerance develop. In the continuation of the same study, Phe4 is chlorinated so as to assess the effect of chlorination on the conformation, lipophilicity and analgesia of chimeric peptide [p-Cl Phe4] YFa. Not only does the chlorination increase the lipophilicity but also enhances the propensity of [p-Cl Phe4] YFa to form alpha helix in comparison of YFa in presence of membrane mimicking solvent trifluoroethanol (TFE). This increase in lipophilicity and helix-forming ability results in more bioavailability and naloxone-reversible analgesia by [p-Cl Phe4] YFa. Though analgesia produced by [p-Cl Phe4] YFa is more than YFa at all doses, there is sudden decrease in analgesia at 45 and 60 min at 60 mg/kg. This sudden decrease of analgesia seems to be due to desensitization of opioid receptors