Purification and characterisation of alliinase produced by Cupriavidus necator and its application for generation of cytotoxic agent: Allicin

Allicin, an extremely active constituent of freshly crushed garlic, is produced upon reaction of alliin with the enzyme alliinase (EC 4.4.1.4). A bacterium Cupriavidus necator with the ability of alliinase production was isolated from a soil sample and was identified by morphological, biochemical and 16S rRNA sequence. Alliinase production was optimised and it was further purified to apparent homogeneity with 103-fold purification and specific activity of 209 U/mg of protein by using DEAE Cellulose and Sephadex G-100 chromatography. The enzyme is a homodimer of molecular weight 110 kDa with two subunits of molecular weight 55 kDa each. The optimum activity of the purified enzyme was found at pH 7 and the optimum temperature was 35 °C. The enzyme exhibited maximum reaction rate (V_max) at 74.65 U/mg and Michaelis–Menten constant (K_m) was determined to be 0.83 mM when alliin was used as a substrate. The cytotoxic activity of in-situ generated allicin using purified alliinase and alliin was assessed on MIA PaCa-2 cell line using MTT assay and Acridine orange–ethidium bromide staining. This approach of in-situ allicin generation suggests a novel therapeutic strategy wherein alliin and alliinase work together synergistically to produce cytotoxic agent allicin.     

Interaction for food and space between populations of Galaxias vulgaris Stokell and juvenile Salmo trutta L. in a New Zealand stream

The trophic and spatial interrelationships between a native ( Galaxias vulguris Stokell, Galaxiidae) and an exotic ( Salmo trutta L., Salmonidae) fish species were investigated over a 24-h period in a New Zealand stream. Interspecific overlap in feeding was greatest at dusk and dawn, as G. vulgaris fed primarily from dusk to post-dawn and S. trutta fed primarily from pre-dawn to post-dusk. Both species fed mainly on benthic and drifting aquatic invertebrates, with larval Deleatidium (Ephemeroptera). Hydora (Coleoptera) and Chironomidae (Diptera) being their preferred prey, although Trichoptera imagos were also preferred by S. trutta . Both species were found primarily in runs and riffles with G. vulgaris occupying slightly shallower (≤0.3 m) and faster (0.3–0.7 m s¹) waters than did S. trutta (≤0.5 m deep and 0.2–0.4 m s⁻¹ water velocity). We suggest that these rather subtle interspecifc differences in die1 feeding periodicities, diets and microdistributions play a part in lessening the interaction between co-occurring populations of G. wlguris and S. trutta .     

Design, synthesis and pharmacological screening of a series of N1-(substituted) aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)-pyrimidin-4(3H)-ones as potential histamine H1-receptor antagonists

A series of N1-(substituted)aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)pyrimidin-4(3H)-one was designed on the basis of the triangular pharmacophoric requirement of histamine H1-receptor antagonists. The designed series was synthesized by cyclo-condensation of monoaryl thiourea with ethyl cyanoacetate in the presence of dry HCl gas to give N1-(substituted aryl)-2-mercaptopyrimidine-4(3H)-one, which on cyclo-condensation with acetylacetone gave the pyridopyrimidinone. Further methylation of the mercapto group at C-2 with methyl iodide followed by nucleophilic displacement of the methylmercapto group by various amines gave the targeted compounds. All the synthesized compounds were screened for histamine H1-receptor antagonistic activity by the in vitro method of inhibition of the isotonic contraction induced by histamine on isolated guinea pig ileum using cetirizine as a standard drug. All the compounds exhibited potent histamine H1-receptor antagonistic activity with pA2 values from 7.30- 9.75 (cetirizine, pA2 value 9.40). The potent compounds were screened for their in vivo antihistaminic activity by protection of animal from asphyxic shock. The sedative potential of potent compounds was checked on albino mice by photoactometer and they had comparative sedative potential to the standard drug cetirizine. None of the compound exhibited anticholinergic activity in the in vitro rat ileum model.     

In vitro activity of 11 antibiotics against 74 anaerobes isolated from pediatric intra-abdominal infections

The in vitro activity of 11 antimicrobials was tested against 74 recent anaerobic isolates obtained from pretreatment cultures in pediatric patients with complicated intra-abdominal infections using the CLSI M11-A-6 agar dilution method. Carbapenems, beta-lactamase inhibitor combinations and metronidazole retained good activity, while all Bacteroides fragilis group species produced beta-lactamase and were penicillin resistant and 43% were either intermediately susceptible or resistant to clindamycin. Cefoxitin had moderate activity against B. fragilis but poor activity against Bacteroides thetaiotaomicron and other B. fragilis group isolates.     

Inhibiting the β1integrin subunit increases the strain threshold for neuronal dysfunction under tensile loading in collagen gels mimicking innervated ligaments

Biomechanics and Modeling in Mechanobiology - Stretch injury of the facet capsular ligament is a cause of neck pain, inducing axonal injury, neuronal hyperexcitability, and upregulation of pain...