BackgroundWhile many studies have shown that extracellular proteins evolve rapidly, how selection acts on them remains poorly understood. We used snake venoms to understand the interaction between ecology, expression level, and evolutionary rate in secreted protein systems. Venomous snakes employ well-integrated systems of proteins and organic constituents to immobilize prey. Venoms are generally optimized to subdue preferred prey more effectively than non-prey, and many venom protein families manifest positive selection and rapid gene family diversification. Although previous studies have illuminated how individual venom protein families evolve, how selection acts on venoms as integrated systems, is unknown.ResultsUsing next-generation transcriptome sequencing and mass spectrometry, we examined microevolution in two pitvipers, allopatrically separated for at least 1.6 million years, and their hybrids. Transcriptomes of parental species had generally similar compositions in regard to protein families, but for a given protein family, the homologs present and concentrations thereof sometimes differed dramatically. For instance, a phospholipase A2 transcript comprising 73.4 % of the Protobothrops elegans transcriptome, was barely present in the P. flavoviridis transcriptome (<0.05 %). Hybrids produced most proteins found in both parental venoms. Protein evolutionary rates were positively correlated with transcriptomic and proteomic abundances, and the most abundant proteins showed positive selection. This pattern holds with the addition of four other published crotaline transcriptomes, from two more genera, and also for the recently published king cobra genome, suggesting that rapid evolution of abundant proteins may be generally true for snake venoms. Looking more broadly at Protobothrops, we show that rapid evolution of the most abundant components is due to positive selection, suggesting an interplay between abundance and adaptation.ConclusionsGiven log-scale differences in toxin abundance, which are likely correlated with biosynthetic costs, we hypothesize that as a result of natural selection, snakes optimize return on energetic investment by producing more of venom proteins that increase their fitness. Natural selection then acts on the additive genetic variance of these components, in proportion to their contributions to overall fitness. Adaptive evolution of venoms may occur most rapidly through changes in expression levels that alter fitness contributions, and thus the strength of selection acting on specific secretome components.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1832-6) contains supplementary material, which is available to authorized users.

Aptamers, the chemical-antibody substitute to conventional antibodies, are primarily discovered through SELEX technology involving multi-round selections and enrichment. Circumventing conventional methodology, here we report an in silico selection of aptamers to estrogen receptor alpha (ERα) using RNA analogs of human estrogen response elements (EREs). The inverted repeat nature of ERE and the ability to form stable hairpins were used as criteria to obtain aptamer-alike sequences. Near-native RNA analogs of selected single stranded EREs were modelled and their likelihood to emerge as ERα aptamer was examined using AutoDock Vina, HADDOCK and PatchDock docking. These in silico predictions were validated by measuring the thermodynamic parameters of ERα -RNA interactions using isothermal titration calorimetry. Based on the in silico and in vitro results, we selected a candidate RNA (ERaptR4; 5′-GGGGUCAAGGUGACCCC-3′) having a binding constant (Ka) of 1.02 ± 0.1 × 108 M−1 as an ERα-aptamer. Target-specificity of the selected ERaptR4 aptamer was confirmed through cytochemistry and solid-phase immunoassays. Furthermore, stability analyses identified ERaptR4 resistant to serum and RNase A degradation in presence of ERα. Taken together, an efficient ERα-RNA aptamer is identified using a non-SELEX procedure of aptamer selection. The high-affinity and specificity can be utilized in detection of ERα in breast cancer and related diseases.

Mucoadhesion can be defined as adhesion in biological setting. Process of mucoadhesion takes place in 3 stages- the first stage being that of wetting or swelling of mucoadhesive polymer. Second stage involves interpenetration of the chains of mucoadhesive polymer and the third stage involves formation of chemical bonds between entangled chains. Several polymer related factors like molecular weight, chain length, degree of cross-linking, hydration, functional groups, charge, polymer concentration and several environmental and physiological factors like contact time, mucin turnover rate and mucus viscosity affect the degree of mucoadhesion. Formulation scientists have structured and engineered several mucoadhesive polymers for their usefulness in enhancement of bioavailability, controlled and targeted drug delivery. Mucoadhesive polymers can be classified as non-specific first generation polymers and novel second generation polymers based on the mechanism of mucoadhesion. Mucoadhesive drug delivery systems have been applied to buccal cavity, oesophagus, gastrointestinal tract, eye, nasal cavity, vagina and rectal cavity. Several in vitro/ex vivo and in vivo evaluation techniques have evolved for the evaluation of mucoadhesive strength of these polymers. This review provides historical perspective on mucoadhesive polymers and an understanding of the phenomenon of mucoadhesion, factors affecting mucoadhesion, types of mucoadhesive polymers, their practical applications and the various evaluation techniques for determination of mucoadhesive strength.

Transfusion of blood and blood products is a double edged sword, so it should be used judiciously. The primary aim of the centralized Haemovigilance Program is to improve transfusion safety. To determine the incidence of adverse transfusion reactions (ATRs) in recipients of blood and blood components. Prospective study from January 2014 till April 2015 was done. ATRs reported to the Department of Transfusion Medicine were recorded and analyzed on the basis of their clinical features and lab tests. During the study period 25,099 units of blood and blood components were transfused and 100 ATRs (0.40 %) were reported. The incidence of febrile nonhemolytic transfusion reactions (FNHTR) was maximum (73 %) followed by allergic reactions (24 %), bacterial sepsis (1 %), hypotension due to ACE inhibitors (1 %) and acute hemolytic transfusion reaction (AHTR) (1 %). Of all the reported ATRs, 76 % occurred with packed red cells, 15 % occurred with whole blood, while platelets and Fresh Frozen Plasma transfusions were responsible for 8 % and 1 %, respectively. The majority of the reactions were FNHTRs followed by allergic reactions. Reporting of all adverse events and continuous medical education to medical and paramedical staff will help in strengthening hemovigilance system.