l-Phenylalanine Partitioning Mechanisms in Model Biological Membranes.

Time-resolved fluorescence spectroscopy in combination with differential scanning calorimetry (DSC) was used to study the chemical interactions that occur when l-phenylalanine is introduced to solutions containing phosphatidylcholine vesicles. Studies reported in this work address open questions about l-Phe's affinity for lipid vesicle bilayers, the effects of l-Phe partitioning on bilayer properties, l-Phe's solvation within a lipid bilayer, and the amount of l-Phe within that local solvation environment. DSC data show that l-Phe reduces the amount of heat necessary to melt saturated phosphatidylcholine bilayers from their gel to liquid-crystalline state but does not change the transition temperature (Tgel-lc). Time-resolved emission shows only a single l-Phe lifetime at low temperatures corresponding to l-Phe remaining solvated in aqueous solution. At temperatures close to Tgel-lc, a second, shorter lifetime appears that is assigned to l-Phe already embedded within the membrane that becomes hydrated as water starts to permeate the lipid bilayer. This new lifetime is attributed to a conformationally restricted rotamer in the bilayer's polar headgroup region and accounts for up to 30% of the emission amplitude. Results reported for dipalmitoylphosphatidylcholine (DPPC, 16:0) lipid vesicles prove to be general, with similar effects observed for dimyristoylphosphatidylcholine (DMPC, 14:0) and distearoylphosphatidylcholine (DSPC, 18:0) vesicles. Taken together, these results create a complete and compelling picture of how l-Phe associates with model biological membranes. Furthermore, this approach to examining amino acid partitioning into membranes and the resulting solvation forces points to new strategies for studying the structure and chemistry of membrane-soluble peptides and selected membrane proteins.

Draft Genome Sequence of the Yeast Ogataea degrootiae Strain UCD465, Isolated from Soil in Ireland.

Ogataea degrootiae is an ascomycete yeast that was first isolated in the Netherlands in 2017. It is a member of the Pichiaceae clade. Here, we present the genome sequence of O. degrootiae UCD465, which was isolated from soil in Ireland. This genome is 14.6 Mb and haploid.

Cyclization kinetics and biological evaluation of an anticancer 1,2-dialkynylimidazole.

1,2-Dialkynylimidazoles have been reported to undergo thermal cyclization/rearrangement to diradical and carbene intermediates. Optimization of the synthesis of the 1,2-dialkynylimidazole has provided sufficient material for kinetic and biological studies. The 1,2-dialkynylimidazole is cytotoxic against a wide range of cancer cells and induces apoptosis in A549 cells. Experimentally-determined kinetics of the thermolysis of (E(a) = 30.0 kcal mol(-1)) are in excellent agreement with DFT calculations of the cyclization/rearrangement to diradical and cyclopentapyrazine carbene intermediates (E(a) = 29.7 kcal mol(-1)). Commensurate with the relatively high barrier for cyclization of , no evidence for cleavage of supercoiled DNA under physiological conditions was found; however, under aqueous conditions at 70 degrees C formed a covalent adduct with a model peptide. These studies indicate that if cyclization of is involved in its anticancer activity, the cyclization must be facilitated, perhaps through initial protein binding, which could lead to covalent protein modification.

Premorbid adjustment in bipolar disorder: comparison with schizophrenia.

Knowledge that poor premorbid adjustment (PMA) precedes illness onset in many schizophrenia cases can facilitate early detection. Increasing consideration is being given to a similar early detection strategy for bipolar disorder (BPD). Results of this preliminary investigation comparing PMA in BPD (N = 53) and schizophrenia (N = 39) outpatients revealed a significant difference at the late adolescent (F[1,58] = 4.499, p = 0.038) stage only, with specific differences in two areas of PMA: adaptation to school (t [58] = 1.83, p = 0.036) and social sexual functioning (t [58] = 2.441, p = 0.009). However, mood state may affect some PMA ratings in BPD. Depression ratings were not correlated with reported late adolescent PMA, but a significant, positive correlation was found for the childhood stage (r = 0.32, p = 0.02). Findings fail to support a trend similar to schizophrenia of deteriorating PMA in BPD; however, the approach to investigations of PMA in BPD may need to be reconsidered.

Estudio comparativo de la funcion respiratoria en Niños bolivianos de la altura y el tropico; influencia del estado nutricional y antropometrico / Comparative study of respiratory function of Bolivian children and the influence of the nutritional and anthropometric status

Nuestro proposito tiene una doble finalidad, en primer lugar hacer un analisis de los factores que contribuyen en la funcion respiratoria de niños expuestos a diferentes ambientes ecologicos, altura y tropico y de diferente estado nutricional; en segundo lugar un estudio comparativo que permite ratificar los valores de referencia establecidos con el fin de efectuar una evaluacion funcional en patologia respiratoria infantil. Se comparan los volumenes pulmonares de cuatro grupos de niños en edad prepuberal habitantes de altura (LA PAz 3700 m sobre el nivel del mar, presion barometrica: 495 mmHg y de tierras bajas (Santa Cruz, 420 msnm, presion barometrica: 760 mmHg). El grupo de la altura GA (N=67) fue estudiado en el Instituto Boliviano de Altura (I.B.B.A), y dividido en dos subgrupos GA1 que corresponde a niños de nivel socioeconomico de nivel alto (N=23) y GA2 de nivel socioeconomico bajo (N=44). El grupo de tierras bajas GB (N=71) fue estudiado en CENETROP, y dividido en dos subgrupos GB1 formados por niños de nivel socioeconomicos altos (N=43) y GB2 de nivel socioeconomico bajo (N=28).