Synthesis of isomeric 11-hydroxy 11-methyl prostaglandins

The synthesis of several novel 11-substituted prostaglandins has been achieved from PGA₂ methyl ester from the marine coral . The configuration of the substituents at position 11 is based on the nuclear magnetic resonance properties.     

Atg11

Selective macroautophagy uses double-membrane vesicles, termed autophagosomes, to transport cytoplasmic pathogens, organelles and protein complexes to the vacuole for degradation. Autophagosomes are formed de novo by membrane fusion events at the phagophore assembly site (PAS). Therefore, precursor membrane material must be targeted and transported to the PAS. While some autophagy-related (Atg) proteins, such as Atg9 and Atg11, are known to be involved in this process, most of the mechanistic details are not understood. Previous work has also implicated the small Rab-family GTPase Ypt1 in the process, identifying Trs85 as a unique subunit of the TRAPPIII targeting complex and showing that it plays a macroautophagy-specific role; however, the relationship between Ypt1, Atg9 and Atg11 was not clear. Now, a recent report shows that Atg11 is a Trs85-specific effector of the Rab Ypt1, and may act as a classic coiled-coil membrane tether that targets Atg9-containing membranes to the PAS. Here, we review this finding in the context of what is known about Atg11, other Rab-dependent coiled-coil tethers, and other tethering complexes involved in autophagosome formation.     

Production of 19-hydroxy-11-deoxycorticosterone and 19-oxo-11-deoxycorticosterone from 11-deoxycorticosterone by cytochrome P-450(11)beta

Incubation of 11-deoxycorticosterone with a cytochrome P-450(11)beta-reconstituted system yielded, in addition to corticosterone and 18-hydroxy-11-deoxycorticosterone, a new steroid product. The retention time of the new product was identical with that of authentic 19-hydroxy-11-deoxycorticosterone on high performance liquid chromatography (HPLC). The turnover number of 19-hydroxy-11-deoxycorticosterone formation was 7.0 mol/min/mol P-450. When a large amount of cytochrome P-450(11)beta was used for the reaction and the products were analyzed by HPLC, the 19-hydroxy-11-deoxycorticosterone peak disappeared from the chromatogram and concomitantly new unidentified peaks appeared. These results suggest that 19-hydroxy-11-deoxycorticosterone was further metabolized to other steroids by cytochrome P-450(11)beta. Therefore, we next incubated 19-hydroxy-11-deoxycorticosterone with cytochrome P-450(11)beta and analyzed the reaction products by HPLC. The above-mentioned unidentified peaks appeared again in the chromatogram. The retention time of one of the peaks coincided with that of authentic 19-oxo-11-deoxycorticosterone. This peak substance was purified by repeated HPLC and subjected to mass spectrometry and 1H NMR analyses. Its field desorption mass spectrum (FD-MS) showed a M+ peak at m/e 344. The 1H NMR spectrum showed the signal of an aldehyde proton instead of those of hydroxymethyl protons at the C-19 position. These results suggest that cytochrome P-450(11)beta can catalyze the 19-hydroxylation of 11-deoxycorticosterone, and the 19-hydroxy-11-deoxycorticosterone produced is further oxidized at the C-19 position to 19-oxo-11-deoxycorticosterone.     

MEGA11: Molecular Evolutionary Genetics Analysis Version 11

The Molecular Evolutionary Genetics Analysis (MEGA) software has matured to contain a large collection of methods and tools of computational molecular evolution. Here, we describe new additions that make MEGA a more comprehensive tool for building timetrees of species, pathogens, and gene families using rapid relaxed-clock methods. Methods for estimating divergence times and confidence intervals are implemented to use probability densities for calibration constraints for node-dating and sequence sampling dates for tip-dating analyses. They are supported by new options for tagging sequences with spatiotemporal sampling information, an expanded interactive Node Calibrations Editor, and an extended Tree Explorer to display timetrees. Also added is a Bayesian method for estimating neutral evolutionary probabilities of alleles in a species using multispecies sequence alignments and a machine learning method to test for the autocorrelation of evolutionary rates in phylogenies. The computer memory requirements for the maximum likelihood analysis are reduced significantly through reprogramming, and the graphical user interface has been made more responsive and interactive for very big data sets. These enhancements will improve the user experience, quality of results, and the pace of biological discovery. Natively compiled graphical user interface and command-line versions of MEGA11 are available for Microsoft Windows, Linux, and macOS from www.megasoftware.net.     

Elucidation of structural and antigenic properties of pneumococcal serotype 11A, 11B, 11C, and 11F polysaccharide capsules

Despite the emerging impact of serogroup 11 serotypes in Streptococcus pneumoniae epidemiology, the structures of serogroup 11 capsule types have not been fully elucidated, particularly the locations of O-acetyl substitutions. Here, we report the complete structures of the serotype 11B, 11C, and 11F polysaccharides and a revision to the serotype 11A capsular polysaccharide using nuclear magnetic resonance (NMR). All structures shared a linear, tetrasaccharide backbone with a pendant phosphopolyalcohol. Three of four saccharides are conserved in all serotypes. The individual serotype capsules differed in the identity of one saccharide, the pendant phosphopolyalcohol, and the O-acetylation pattern. Though the assigned locations of O-acetate substitutions in this study differed from those of previous reports, our findings were corroborated with strong correlations to serology and genetics. We examined the binding of serotyping sera to serogroup 11 polysaccharides by using flow cytometry and an inhibition-type enzyme-linked immunosorbent assay (ELISA) and found that de-O-acetylation of capsular polysaccharides by mild hydrolysis decreases its immunoreactivity, supporting the crucial role of O-acetylation in the antigenicity of these polysaccharides. Due to strong correlations between polysaccharide structures and capsule biosynthesis genes, we were able to assign target substrates for the O-acetyltransferases encoded by wcwC, wcwR, wcwT, and wcjE. We identified antigenic determinants for serogroup 11 serotyping sera and highlight the idea that conventional serotyping methods are not capable of recognizing all putative variants of S. pneumoniae serogroup 11.     

Laminin-11.

Laminins are a family of glycoproteins which are ubiquitous components of basement membranes and play key structural and functional roles. Eleven isoforms have been identified to date; each is an alpha beta gamma heterotrimer assembled from a repertoire of five alpha, three beta and two gamma chains. Studies of laminin-11 (alpha 5 beta 2 gamma 1) illustrate the unique expression patterns and distinct functions that can be displayed by laminin isoforms. Laminin-11 is found in the glomerular basement membrane in kidney, in the neuromuscular synaptic cleft in skeletal muscle and in other tissues such as placenta and lung. Mice lacking laminin-11 exhibit defective glomerular filtration and developmental defects in neuromuscular synapse formation, with Schwann cells invading the synaptic cleft. Consistent with these observations, both motoneurons and Schwann cells distinguish laminin-11 from other isoforms in vitro. These results suggest that laminin-11 is a structural component of the basement membrane which influences cell behavior in physiologically relevant ways. A greater understanding of laminin-11 assembly and basement membrane incorporation could provide a logical basis for therapy in merosin-deficient congenital muscular dystrophy.