Mohd. Ashraf

Stereo-Selectivity of Human Serum Albumin to Enantiomeric and Isoelectronic Pollutants Dissected by Spectroscopy, Calorimetry and Bioinformatics

1–naphthol (1N), 2–naphthol (2N) and 8–quinolinol (8H) are general water pollutants. 1N and 2N are the configurational enantiomers and 8H is isoelectronic to 1N and 2N. These pollutants when ingested are transported in the blood by proteins like human serum albumin (HSA). Binding of these pollutants to HSA has been explored to elucidate the specific selectivity of molecular recognition by this multiligand binding protein. The association constants (Kb) of these pollutants to HSA were moderate (104–105 M−1). The proximity of the ligands to HSA is also revealed by their average binding distance, r, which is estimated to be in the range of 4.39–5.37 nm. The binding free energy (ΔG) in each case remains effectively the same for each site because of enthalpy–entropy compensation (EEC). The difference observed between ΔCp exp and ΔCp calc are suggested to be caused by binding–induced flexibility changes in the HSA. Efforts are also made to elaborate the differences observed in binding isotherms obtained through multiple approaches of calorimetry, spectroscopy and bioinformatics. We suggest that difference in dissociation constants of pollutants by calorimetry, spectroscopic and computational approaches could correspond to occurrence of different set of populations of pollutants having different molecular characteristics in ground state and excited state. Furthermore, our observation of enhanced binding of pollutants (2N and 8H) in the presence of hemin signifies that ligands like hemin may enhance the storage period of these pollutants in blood that may even facilitate the ill effects of these pollutants.

Impact of structural stability of cold adapted Candida antarctica lipase B (CaLB): in relation to pH, chemical and thermal denaturation

The effect of pH on the conformational behavior of Candida antartica lipase B (CaLB) has been monitored by spectroscopic and calorimetric studies. The results obtained from far and near-UV CD, intrinsic fluorescence and ANS binding studies indicate that CaLB exhibits the characteristic properties of a molten globule in acidic (protonated) conditions at pH 1.4. The molten globule state retained about 67% of its secondary structure with a substantial loss of tertiary structure at pH 1.4. Moreover, equilibrium unfolding studies indicated that the ‘molten-globule-like’ state unfolds in a non-cooperative manner and is thermodynamically less stable than that of the native state. The molten globule possessed a slightly higher Rh than its native state. The DSC thermogram shows a high heat signal at pH 7.4, and a low heat signal at pH 2.6, and suggests that CaLB is likely to have undergone structural changes during the thermal unfolding. However partially unfolded CaLB at pH 1.4 does not produce a DSC peak which proves the existence of the molten globule state at pH 1.4 as supported by spectroscopic data. The Stokes radius of the MG state obtained by SEC experiments is found to be 33% larger than the native state, but essentially smaller than the denatured state.

Comparative study of effects of polyols, salts, and alcohols on trichloroacetic acid-induced state of cytochrome c

A systematic investigation of the effect of polyethylene glycols, salts, and alcohols on the trichloroacetic acid (TCA)-induced state of ferricytochrome c was made using various spectroscopic techniques. Native cytochrome c (Cyt c) has a fluorescence maximum at 335 nm, where as the TCA-induced state of Cyt c has a red shift of 7 nm with enhanced fluorescence intensity. The near-and far-UVCD spectra showed a significant loss of tertiary and secondary structure, although the protein is relatively less unfolded as compared with a conformation at pH 2.0. Addition of 70% (v/v) polyols to TCA (3.3 mM)-induced state of Cyt c resulted in increased 1-anilino-8-naphthalene sulfonate binding and increased mean residue ellipticity at 222 nm, indicating increase in compactness with enhanced exposure of hydrophobic surface area. Also, the stabilizing effect of salts and alcohols on the TCA-induced state was studied and compared with their effect on trifluoroacetic acid-unfolded state of Cyt c. Among all the polyols, salts, and alcohols studied, PEG-400, K3[Fe(CN)6], and butanol were the most efficient in inducing secondary structure in TCA-induced state as examined by the above-mentioned spectroscopic techniques. For salts, the efficiency in inducing the secondary structure followed the order K3[Fe(CN)6] > KClO4 > K2SO4 > KCl. For alcohols, this order was found to be as follows: butanol > propanol > ethanol > methanol.

Purification and characterization of mannose/glucose-specific lectin from seeds of Trigonella foenumgraecum.

A lectin present in seeds of Trigonella foenumgraecum was isolated and purified by acid precipitation, salt fractionation, and affinity chromatography on mannan cross-linked agarose. SDS-PAGE revealed a single band corresponding to a molecular weight of 27,350 daltons. The lectin agglutinated trypsin-treated rat erythrocytes. Sugar specificity as determined by hemagglutination inhibition assay indicated that the lectin belongs to a glucose/mannose-specific group. The reaction of the lectin with glycoprotein was affected by pH changes. The carbohydrate binding specificity of the lectin was investigated by turbidity and activity measurements. As the lectin belongs to the Leguminoceae family, the specificity of the lectin for glucose/mannose renders it a valuable tool for Rhizobium-legume symbiosis.

Colorectal cancer-inflammatory bowel disease nexus and felony of Escherichia coli

Colorectal cancer (CRC) has a multifactorial etiology. Although the exact cause of CRC is still elusive, recent studies have indicated microbial involvement in its etiology. Escherichia coli has emerged as an important factor in CRC development since the bacterium can cause changes in the gut that lead to cancerous transformation. A number of studies indicate that chronic inflammation induced by microorganisms, including E. coli, during inflammatory bowel disease (IBD) predisposes an individual to CRC. The evidence that support the role of E. coli in the etiology of CRC, through IBD, is not limited only to chronic inflammation. The growth of E. coli as an intracellular pathogen during IBD and CRC enable the bacteria to modulate the host cell cycle, induce DNA damage and accumulate mutations. These are some of the contributing factors behind the etiology of CRC. The present article considers the current status of the involvement of E. coli, through IBD, in the etiology of CRC. We discuss how intracellular E. coli infection can cause changes in the gut that can eventually lead to cellular transformation. In addition, the recent management strategies that target E. coli for prevention of CRC are also discussed.

Certain conditions under which near-rings are rings

In 1969, Ligh proved that distributively generated (d-g) Boolean near-rings are rings, and hinted that some of the more complicated polynomial identities implying commutativity in rings may turn d-g near-rings into rings. In the present paper we investigate the following conditions: (1) xy = ( xy ) n( x, y ) ; (2) xy = ( yz ) n ( xy ) ; (3) xy = y m ( x , y ) x n ( x , y ) ; (4) xy = xy n ( x , y ) x; (5) xy = x n( x , y ) y m ( x , y ) ; finally prove that under appropriate additional hypotheses a d-g near-ring must be a commutative ring. Indeed the theorem proved here is a wide generalisation of many recently established results.

Efficient technique for personalized web search using users browsing history

In todays world, every information available on World Wide Web present in digital form. Different Information retrieval (IR) technique are used for retrieving required information on huge heaps of information but there is great difficulty in retrieving relevant information according to user preferences in return of simple short query with generic web search. So, we need to enhance the power of web search to retrieve relevant information. This paper is an attempt to improve the search efficiency of web search. In this paper, we proposed a framework for personalized web search which uses a dynamic user profile to automatically update user profile and collaborative filtering for considering recommendation which helps to retrieve search result and relevant document to user according to its need and preferences by diagnosing its web search behavior according to previous search history. The Experimental result shows the proposed method of personalized web search is more efficient over generic search engine.

Performance enhancement of classification scheme in data mining using hybrid algorithm

Data mining has been an active area of research for the past couple of decades. Classification is an important data mining technique that consists of assigning a data instance to one of the several predefined categories. Various successful methods have already been suggested and tested to solve the problems of the classification. In this paper, author proposed a new hybrid classifier by combining evolutionary and non-evolutionary algorithms; specifically, by merging Genetic Programming and Decision Tree to improve the accuracy, comprehensibility and timing of the classification.

A theorem on commutativity of semi-prime rings

The following Theorem is proved: Let R be a semi-prime ring in which either ( xy ) n − x n y n or ( xy ) n − y n x n is central, for all x , y in R where n > 1 is a fixed integer. Then R is commutative.

Improving the performance of multi-criteria recommendation system using fuzzy integrated meta heuristic

Recommender systems have been researched in the extreme in recent years, and are implemented in a variety of applications. Increasing number of E-commerce sites on the Internet has made the information overload. In general, users are enabled to provide overall ratings on items but many online systems allow users to provide their ratings on different criterions. So much research work have been made in the past to build a recommendation system focusing on the ratings of a single criterion. However, using the approach of multi criteria recommender systems in online environment is still in its developing phase. This proposed approach recommends the relevant item to the user with the help of Fuzzy Multi-criteria Decision Making approach.