Activation chemistry drives the emergence of functionalised protocells

The complexity of the simplest conceivable cell suggests that the chemistry of prebiotic mixtures needs to be explored to understand the intricate network of prebiotic reactions that led to the emergence of life. Early cells probably relied upon compatible and interconnected chemistries to link RNA, peptides and membranes. Here we show that several types of vesicles, composed of prebiotically plausible mixtures of amphiphiles, spontaneously form and sustain the methyl isocyanide-mediated activation of amino acids, peptides and nucleotides. Activation chemistry also drives the advantageous conversion of reactive monoacylglycerol phosphates into inert cyclophospholipids, thus supporting their potential role as major constituents of protocells. Moreover, activation of prebiotic building blocks within fatty acid-based vesicles yields lipidated species capable of localising to and functionalising primitive membranes. Our findings describe a potentially prebiotic scenario in which the components of primitive cells undergo activation and provide new species that might have enabled an increase in the functionality of protocells.

The complexity of the simplest conceivable cell suggests that the chemistry of prebiotic mixtures needs to be explored to understand the intricate network of prebiotic reactions that led to the emergence of life.     

Conformational changes in diacyl-tetrahydropyridazine and piperidazine systems

Conformational changes in both diacyltetrahydropyridazines and piperidazines have been studied by the NMR method. Processes involving both ring inversion and hindered rotation about the N---COR bonds have been recognized. The energy barriers to ring inversion are unusually high for six membered ring systems and appear to be associated with interaction between the adjacent N-acyl substituents.     

INHERITANCE OF PHOTOREACTIVATING ENZYME DEFICIENCIES IN HUMAN CELLS

Abstract— Cells from patients with xeroderma pigmentosum contain lowered levels of photoreactivating enzyme. We have examined the photoreactivating enzyme levels in cells from members of a family with three xeroderma children, one normal child and normal parents; the enzyme levels are consistent with a simple pattern of inheritance in which individuals with the normal enzyme level are PP , those with intermediate levels are PP , and those with very low enzyme levels are pp. We tested this hypothesis by examining enzyme levels in parent-xeroderma child pairs in which the child possessed very low enzyme levels ( pp ). In all cases, the parents contained intermediate levels of enzyme ( Pp ). These results support the hypothesis of a simple pattern of inheritance of photoreactivating enzyme in humans.     

Zwitterionic species from deprotonation of η6-arene-η5-cyclopentadienyliron cations and their reactions as nucleophiles

A variety of η⁶-arene-η⁵-cyclopentadienyliron cations in which the arene ligand has an α-carbon substituent containing one or more hydrogens can be deprotonated with base to give the corresponding neutral zwitterionic species. These zwitterions can react in situ as nucleaphiles with different substrates such as CH₃I, other organic halides. CO₂ and CS₂ to give a wide range of synthetic applications.     

The extractives of Millettia dura (Dunn) The constitutions of durlettone, durmillone, milldurone, millettone and millettosin

The seeds of Millettia dura (Dunn) have yielded durlettone, durmillone, mildurone, (−)-millettone, (−)-millettosin, (−)-rotenone, (−)-tephrosin, (−)-tephrosin, and 6_ω12_ω-dehydrodeguelin. The constitutions of the new isoflavones durlettone (I), durmillone (IV), and milldurone (VIII) have been established.

Millettone is shown to be the new rotenoid (XIX). The natural co-occurrence of the rotenoids, (−)-millettone (XIX) and (−)-rotenone (XX), with the 12_a-hydroxyrotenoids, (−)-millettosin (XXI) and (−)-tephrosin (XXII), and the 6_a,12₁-dehydrorotenoid, 6_a,12_a-dehydrodeguelin (XII), is established. The relation of these observations to the question of the natural occurrence of 12_a-hydroxyrotenoids and 6_a,12_a-dehydrorotenoids is discussed.     

The Efficiency of Substance Separation in Countercurrent Liquid Chromatography

The effect of hydrodynamic parameters and the specific features of instrument design on the efficiency of substance separation in countercurrent liquid chromatography (CCC) was studied using a constant retention factor of the stationary phase in the column. The study was conducted with the separation of benzyl alcohol and p-cresol in a two-phase liquid system heptane–ethyl acetate–methanol–water (1.4 : 0.6 : 1 : 1) in as an example. It was shown that the peak resolution is improved with an increase in the rotational speed of the column and a decrease in the flow rate of the mobile phase. The best peak separation was attained using columns for which the ratio of the column rotation radius to the radius of column revolution was 0.615. It was shown that countercurrent chromatography allows the separation of substances with low partition constants (K < 1) in dilute solutions. The volume of the test sample may be up to 15% of the total volume of the chromatography column.