The role of early life experience and species differences in alcohol intake in microtine rodents

Social relationships have important effects on alcohol drinking. There are conflicting reports, however, about whether early-life family structure plays an important role in moderating alcohol use in humans. We have previously modeled social facilitation of alcohol drinking in peers in socially monogamous prairie voles. We have also modeled the effects of family structure on the development of adult social and emotional behaviors. Here we assessed whether alcohol intake would differ in prairie voles reared by both parents compared to those reared by a single mother. We also assessed whether meadow voles, a closely related species that do not form lasting reproductive partnerships, would differ in alcohol drinking or in the effect of social influence on drinking. Prairie voles were reared either bi-parentally (BP) or by a single mother (SM). BP- and SM-reared adult prairie voles and BP-reared adult meadow voles were given limited access to a choice between alcohol (10%) and water over four days and assessed for drinking behavior in social and non-social drinking environments. While alcohol preference was not different between species, meadow voles drank significantly lower doses than prairie voles. Meadow voles also had significantly higher blood ethanol concentrations than prairie voles after receiving the same dose, suggesting differences in ethanol metabolism. Both species, regardless of rearing condition, consumed more alcohol in the social drinking condition than the non-social condition. Early life family structure did not significantly affect any measure. Greater drinking in the social condition indicates that alcohol intake is influenced similarly in both species by the presence of a peer. While the ability of prairie voles to model humans may be limited, the lack of differences in alcohol drinking in BP- and SM-reared prairie voles lends biological support to human studies demonstrating no effect of single-parenting on alcohol abuse.     

Unexpected transformation of black hole quenchers in electrophoretic purification of the fluorescein-containing TaqMan probes

The fluorescence quenchers BHQ1 and BHQ2 can be modified by trace amounts of ammonium persulfate, used for initiating gel polymerization, in electrophoretic purification of TaqMan probes using a denaturing polyacrylamide gel. The case study of BHQ1 quencher has demonstrated that a Boyland–Sims reaction proceeds in the presence of ammonium persulfate to give the corresponding sulfate. The absorption maximum of the resulting quencher shifts to the short-wavelength region relative to the absorption maximum of the initial BHQ1. The TaqMan probe containing such a quencher is less efficient as compared with the probe carrying an unmodified BHQ1. The presence of fluorescein in TaqMan probe plays decisive role in this transformation: the quencher modification proceeds at a considerably lower rate when the fluorescein is absent or replaced with a rhodamine dye (for example, R6G). It is assumed that the observed reaction can take place in two ways—both in darkness and in the reaction of the quencher in an excited state due to energy transfer from the fluorophore irradiated by light.     

Functionalized head-to-head hairpin polyamides: synthesis, double-stranded DNA-binding activity and affinity

A series of 4 functionalized head-to-head-linked hairpin oligo(N-methylpyrrole) carboxamides with different linkers have been synthesized. Their ability to bind double-stranded DNA and sequence specificity were compared and the apparent Kd values of their DNA complexes were determined. These compounds, particularly those with iminodiacetic linkers, revealed a high affinity for DNA (Kd = 4.5-4.8 x 10(-9) M) and sequence specific recognition of 9-10 base pairs.     

Optimization of Conditions for Blood Plasma Peptidome Analysis

The conditions for peptidome analysis of blood plasma were optimized and the efficacy of the proposed approach was compared with the methods described in the literature. The method implies solution of two main problems: inactivation of blood plasma proteases and dissociation of peptides from major blood plasma proteins, which they are quantitatively associated with. To solve these problems, we proposed a new method of sample preparation. The essence of the method is simultaneous denaturation of plasma proteins plus reduction and alkylation of thiol groups of Cys, which is achieved by heating a blood plasma sample (95°C) in the presence of sodium deoxycholate, tris(2-carboxyethyl)phosphine, and 2-chloroacetamide. After separation of peptides from proteins by ultrafiltration on microcentrifuge filters and removal of sodium deoxycholate, the peptides are identified by LC-MS/MS using a Q Exactive HF (Thermo Scientific) mass spectrometer. As a result of one LC-MS/MS run of the peptide mixture obtained from ~15 μL of blood plasma, 2257 peptide fragments of 867 proteins were identified, which is 1.5 times higher than the values achieved by using the generally accepted method of differential solubilization. Our immediate plans include the use of our approach for cataloguing human blood plasma peptides, as well as establishing the magnitude of individual variability and the features of the peptidome that are related to gender and age.     

Ribosomal RNA secondary structure: compensatory mutations and implications for phylogenetic analysis

Using sequence data from the 28S ribosomal RNA (rRNA) genes of selected vertebrates, we investigated the effects that constraints imposed by secondary structure have on the phylogenetic analysis of rRNA sequence data. Our analysis indicates that characters from both base-pairing regions (stems) and non-base-pairing regions (loops) contain phylogenetic information, as judged by the level of support of the phylogenetic results compared with a well-established tree based on both morphological and molecular data. The best results (the greatest level of support of well-accepted nodes) were obtained when the complete data set was used. However, some previously supported nodes were resolved using either the stem or loop bases alone. Stem bases sustain a greater number of compensatory mutations than would be expected at random, but the number is < 40% of that expected under a hypothesis of perfect compensation to maintain secondary structure. Therefore, we suggest that in phylogenetic analyses, the weighting of stem characters be reduced by no more than 20%, relative to that of loop characters. In contrast to previous suggestions, we do not recommend weighting of stem positions by one-half, compared with that of loop positions, because this overcompensates for the constraints that selection imposes on the secondary structure of rRNA.