Virulence of silver-resistant mutant ofKlebsiella pneumoniae in burn wound model

A silver-resistant mutant ofKlebsiella pneumoniae B-5 was produced by passaging in nutrient broth containing graded concentrations of silver nitrate up to 150 ppm. The development of silver resistance in the strain resulted in rough colonies, decrease in cell size, carbohydrate content and change in klebocin pattern. The virulence of the Ag^R strain as checked by the burn wound model decreased as the mutant could not establish itself in the skin and spleen of the animals and the organism was cleared more efficiently by human lymphocytes than the parent Ag^S strain.     

Glaucoma: An Extension of Various Chronic Neurodegenerative Disorders

The eyes are the window of the brain; various pathologies of the eyes can be explained on the basis of neurological disorders and vice versa. Today, our only approach for the management of glaucoma is intraocular pressure (IOP) reduction, whether by pharmacological or surgical methods. Available methods may effectively control IOP but fall short of stopping the progression of glaucoma. IOP is just one of the risk factors our therapy addresses, so we need to work towards shifting our approach towards addressing other factors involved in the etiopathogenesis of the disease. Pathogenesis of glaucoma at molecular level can be compared with that of common neurodegenerative diseases like Alzheimer’s and Parkinsonism. Targets for therapeutic intervention in chronic neurodegenerative diseases and glaucoma include apoptosis, axonal transport, free radical damage, role of polyunsaturated fatty acids, chaperones, gene regulation, etc. p38MAPK is a common pathway involved in all the neurodegenerative disease and glaucoma as well, and more research in this direction can be really beneficial for the development of novel diagnostic and therapeutic measures.     

Synthesis and evaluation of in vitro antioxidant capacities of some benzimidazole derivatives

New, except 1d, melatonin analogue benzimidazole derivatives were synthesized and characterized in the present study. The potential role of melatonin as an antioxidant by scavenging and detoxifying ROS raised the possibility that compounds that are analogous to melatonin can also be used for their antioxidant properties. Therefore the antioxidant effects of the newly synthesized compounds were investigated in vitro by means of their inhibitory effect on hydrogen peroxide-induced erythrocyte membrane lipid peroxidation (EMLP) and on various erythrocyte antioxidant enzymes viz. superoxide dismutase (SOD), catalase (CAT) and glucose-6-phosphate dehydrogenase (G6PD). The synthesized benzimidazole derivatives showed remarkable antioxidant activity in vitro in the H₂O₂-induced EMLP system. Furthermore their effects on various antioxidant enzymes are discussed and evaluated from the perspective of structure- activity relationships.     

Functional screening of enzymes and bacteria for the dechlorination of hexachlorocyclohexane by a high-throughput colorimetric assay

Two distinct microbial dehalogenases are involved in the first steps of degradation of hexachlorocyclohexane (HCH) isomers. The enzymes, LinA and LinB, catalyze dehydrochlorination and dechlorination reactions of HCH respectively, each with distinct isomer specificities. The two enzymes hold great promise for use in the bioremediation of HCH residues in contaminated soils, although their kinetics and isomer specificities are currently limiting. Here we report the functional screening of a library of 700 LinA and LinB clones generated from soil DNA for improved dechlorination activity by means of a high throughput colorimetric assay. The assay relies upon visual colour change of phenol red in an aqueous medium, due to the pH drop associated with the dechlorination reactions. The assay is performed in a microplate format using intact cells, making it quick and simple to perform and it has high sensitivity, dynamic range and reproducibility. The method has been validated with quantitative gas chromatographic analysis of promising clones, revealing some novel variants of both enzymes with superior HCH degrading activities. Some sphingomonad isolates with potentially superior activities were also identified.     

Local host ant specificity of Phengaris (Maculinea) teleius butterfly,an obligatory social parasite of Myrmica ants

1. Phengaris butterflies are obligatory social parasites of Myrmica ants. Early research suggested that there is a different Myrmica host species for each of the five European Phengaris social parasites, but more recent studies have shown that this was an oversimplification. 2. The pattern of host ant specificity within a Phengaris teleius metapopulation from southern Poland is reported. A combination of studying the frequency distribution of Phengaris occurrence and morphometrics on adult butterflies were used to test whether use of different host species is reflected in larval development. 3. Phengaris teleius larvae were found to survive in colonies of four Myrmica species: M. scabrinodis, M. rubra, M. ruginodis, and M. rugulosa. Myrmica scabrinodis was the most abundant species under the host plant but the percentage of infested nests was similar to other host ant species at two sites and lower in comparison to nests of M. rubra and M. ruginodis at the other two sites. Morphometric measurements of adult butterflies reared by wild colonies of M. scabrinodis and M. ruginodis showed that wing size and number of wing spots were slightly greater for adults eclosing from nests of M. ruginodis. 4. Our results suggest that P. teleius in the populations studied is less specialised than previously suggested. The results are consistent with the hypothesis that P. teleius is expected to be the least specific of the European Phengaris species, as it has the largest and best defended fourth‐instar caterpillars and, as a predatory species, it spends less time in the central larval chambers of the host colonies. The fact that individuals reared by M. ruginodis had wider hind wings may suggest that P. teleius had better access to resources in M. ruginodis than in M. scabrinodis colonies.     

Protective role of IL-18 −137G/C polymorphism in a North Indian population with asthma: A pilot study

BackgroundIL-18, a pleiotropic, pro-inflammatory cytokine that plays a major role in innate as well as acquired immunity, has been implicated in asthma etiology and this is the first study investigating the role of IL-18 ?137G/C (rs 187238) promoter polymorphism in asthma pathogenesis in a North Indian population.MethodsA pilot study was conducted with a total of 824 subjects, out of which 410 were asthma patients including 323 patients suffering from allergic rhinitis and 414 healthy controls from regions of North India. Tetra-Primer Amplification Refractory Mutation System Polymerase Chain Reaction (Tetra-Primer ARMS PCR) was used for genotyping the IL-18 ?137G/C polymorphism.ResultsWhile the homozygous wild (GG) genotype was equally prevalent in asthma patients as well as control subjects (70.0%), the homozygous mutant (CC) genotype was more prevalent among the controls (8.0%) than in asthma patients (3.4%), which yielded a significant protection or decreased risk towards asthma. Statistical analysis revealed Odds Ratio (OR) = 0.43 (95% CI = 0.21–0.85), Chi² (χ²) = 6.93 and p-value = 0.008 (p < 0.005). Moreover, a few asthma phenotypic traits also revealed significant protective associations with the polymorphism.ConclusionsThe IL-18 ?137G/C polymorphism confers a significant protection from asthma in the studied North Indian population. This is the first study to report the protective association of the polymorphism with the disease.     

Disease-associated glycosylated molecular variants of human C-reactive protein activate complement-mediated hemolysis of erythrocytes in tuberculosis and Indian visceral leishmaniasis

Human C-reactive protein (CRP), as a mediator of innate immunity, removed damaged cells by activating the classical complement pathway. Previous studies have successfully demonstrated that CRPs are differentially induced as glycosylated molecular variants in certain pathological conditions. Affinity-purified CRPs from two most prevalent diseases in India viz. tuberculosis (TB) and visceral leishmaniasis (VL) have differential glycosylation in their sugar composition and linkages. As anemia is a common manifestation in TB and VL, we assessed the contributory role of glycosylated CRPs to influence hemolysis via CRP-complement-pathway as compared to healthy control subjects. Accordingly, the specific binding of glycosylated CRPs with erythrocytes was established by flow-cytometry and ELISA. Significantly, deglycosylated CRPs showed a 7–8-fold reduced binding with erythrocytes confirming the role of glycosylated moieties. Scatchard analysis revealed striking differences in the apparent binding constants (10⁴–10⁵ M⁻¹) and number of binding sites (10⁶–10⁷sites/erythrocyte) for CRP on patients’ erythrocytes as compared to normal. Western blotting along with immunoprecipitation analysis revealed the presence of distinct molecular determinants on TB and VL erythrocytes specific to disease-associated CRP. Increased fragility, hydrophobicity and decreased rigidity of diseased-erythrocytes upon binding with glycosylated CRP suggested membrane damage. Finally, the erythrocyte-CRP binding was shown to activate the CRP-complement-cascade causing hemolysis, even at physiological concentration of CRP (10 μg/ml). Thus, it may be postulated that CRP have a protective role towards the clearance of damaged-erythrocytes in these two diseases.