1.Ontogenetic Variation in Biological Activities of Venoms from Hybrids between Bothrops erythromelas and Bothrops neuwiedi Snakes.
Santoro ML1, do Carmo T1, Cunha BH1, Alves AF1, Zelanis A2, Serrano SM2, Grego KF3, Sant'Anna SS3, Barbaro KC4, Fernandes W3. PLoS One. 2015 Dec 29;10(12):e0145516. doi: 10.1371/journal.pone.0145516. eCollection 2015.
Lance-headed snakes are found in Central and South America, and they account for most snakebites in Brazil. The phylogeny of South American pitvipers has been reviewed, and the presence of natural and non-natural hybrids between different species of Bothrops snakes demonstrates that reproductive isolation of several species is still incomplete. The present study aimed to analyze the biological features, particularly the thrombin-like activity, of venoms from hybrids born in captivity, from the mating of a female Bothrops erythromelas and a male Bothrops neuwiedi, two species whose venoms are known to display ontogenetic variation. Proteolytic activity on azocoll and amidolytic activity on N-benzoyl-DL-arginine-p-nitroanilide hydrochloride (BAPNA) were lowest when hybrids were 3 months old, and increased over body growth, reaching values similar to those of the father when hybrids were 12 months old. The clotting activity on plasma diminished as hybrids grew; venoms from 3- and 6-months old hybrids showed low clotting activity on fibrinogen (i.
2.Effect of chlorhexidine chip in the treatment of chronic periodontitis.
Kumar AJ1, Ramesh Reddy BV1, Chava VK1. J Nat Sci Biol Med. 2014 Jul;5(2):268-72. doi: 10.4103/0976-9668.136159.
AIMS: The evaluation of clinical and specific microbiological changes associated with chlorhexidine chip in the chronic periodontitis patients.
3.Effect of midgut proteolytic activity on susceptibility of lepidopteran larvae to Bacillus thuringiensis subsp. Kurstaki.
Talaei-Hassanloui R1, Bakhshaei R1, Hosseininaveh V1, Khorramnezhad A1. Front Physiol. 2014 Jan 16;4:406. doi: 10.3389/fphys.2013.00406. eCollection 2013.
Bacillus thuringiensis (Bt) is the most effective microbial control agent for controlling numerous species from different insect orders. All subspecies and strains of B. thuringiensis can produce a spore and a crystalline parasporal body. This crystal which contains proteinaceous protoxins is dissolved in the alkaline midgut, the resulting molecule is then cleaved and activated by proteolytic enzymes and acts as a toxin. An interesting aspect of this activation process is that variations in midgut pH and protease activity have been shown to account for the spectrum of some Bt proteins activity. Thus, an important factor that could be a determinant of toxin activity is the presence of proteases in the midgut microenvironment of susceptible insects. Reciprocally, any alteration in the midgut protease composition of the host can result in resistance to Bt. Here in this paper, we reviewed this processes in general and presented our assays to reveal whether resistance mechanism to Bt in Diamondback Moth (DbM) larvae could be due to the function of the midgut proteases? We estimated LC50 for both probable susceptible and resistant populations in laboratory and greenhouse tests.
4.Kinetics of trypsin-catalyzed hydrolysis determined by isothermal titration calorimetry.
Maximova K1, Trylska J2. Anal Biochem. 2015 Oct 1;486:24-34. doi: 10.1016/j.ab.2015.06.027. Epub 2015 Jun 25.
Isothermal titration calorimetry (ITC) was applied to determine enzymatic activity and inhibition. We measured the Michaelis-Menten kinetics for trypsin-catalyzed hydrolysis of two substrates, casein (an insoluble macromolecule substrate) and Nα-benzoyl-dl-arginine β-naphthylamide (a small substrate), and estimated the thermodynamic parameters in the temperature range from 20 to 37°C. The inhibitory activities of reversible (small molecule benzamidine) and irreversible (small molecule phenylmethanesulfonyl fluoride and macromolecule α1-antitrypsin) inhibitors of trypsin were also determined. We showed the usefulness of ITC for fast and direct measurement of inhibition constants and half-maximal inhibitory concentrations and for predictions of the mechanism of inhibition. ITC kinetic assays could be an easy and straightforward way to estimate Michaelis-Menten constants and the effectiveness of inhibitors as well as to predict the inhibition mechanism.