The structure of novel C35 pentacyclic terpenes from Acetobacter xylinum

A novel C(35) terpene and its monounsaturated analogue were isolated from cultures of Acetobacter xylinum, together with traces of their C(36) homologues. These substances were found to be hopane derivatives substituted by a five-carbon chain bearing four vicinal hydroxyl groups. For the parent hydrocarbon the term bacteriohopane is proposed. The elucidation of the structures utilized high-resolution mass spectrometry of the terpenes, degradation to C(32) hydrocarbons and detailed mass-spectrometric comparison of these with C(32) hydrocarbons synthesized from known pentacyclic triterpenes. High-resolution mass-spectral data of the terpenes are presented. N.m.r. data are in agreement with the proposed structures, which are further supported by the isolation from the same organism of 22-hydroxyhopane and derivative hopene(s).     

Targeting, import, and dimerization of a mammalian mitochondrial ATP binding cassette (ABC) transporter, ABCB10 (ABC-me)

ATP binding cassette (ABC) transporters are a diverse superfamily of energy-dependent membrane translocases. Although responsible for the majority of transmembrane transport in bacteria, they are relatively uncommon in eukaryotic mitochondria. Organellar trafficking and import, in addition to quaternary structure assembly, of mitochondrial ABC transporters is poorly understood and may offer explanations for the paucity of their diversity. Here we examine these processes in ABCB10 (ABC-me), a mitochondrial inner membrane erythroid transporter involved in heme biosynthesis. We report that ABCB10 possesses an unusually long 105-amino acid mitochondrial targeting presequence (mTP). The central subdomain of the mTP (amino acids (aa) 36-70) is sufficient for mitochondrial import of enhanced green fluorescent protein. The N-terminal subdomain (aa 1-35) of the mTP, although not necessary for the trafficking of ABCB10 to mitochondria, participates in the proper import of the molecule into the inner membrane. We performed a series of amino acid mutations aimed at changing specific properties of the mTP. The mTP requires neither arginine residues nor predictable alpha-helices for efficient mitochondrial targeting. Disruption of its hydrophobic character by the mutation L46Q/I47Q, however, greatly diminishes its efficacy. This mutation can be rescued by cryptic downstream (aa 106-715) mitochondrial targeting signals, highlighting the redundancy of this protein's targeting qualities. Mass spectrometry analysis of chemically cross-linked, immunoprecipitated ABCB10 indicates that ABCB10 embedded in the mitochondrial inner membrane homodimerizes and homo-oligomerizes. A deletion mutant of ABCB10 that lacks its mTP efficiently targets to the endoplasmic reticulum. Quaternary structure assembly of ABCB10 in the ER appears to be similar to that in the mitochondria.     

Fitting the message to the location: engaging adults with antimicrobial resistance in a World War 2 air raid shelter

Aims

There are many different initiatives, global and local, designed to raise awareness of antimicrobial resistance (AMR) and change audience behaviour. However, it is not possible to assess the impact of specific, small‐scale events on national and international outcomes—although one might acknowledge some contribution to the individual and collective knowledge and experience‐focused ‘science capital’ As with any research, in preparation for a public engagement event, it is important to identify aims, and appropriate methods whose results might help satisfy those aims. Therefore, the aim of this paper was to develop, deliver and evaluate an event designed to engage an adult audience with AMR.

Methods and Results

The venue was a World War 2 air raid shelter, enabling comparison of the pre‐ and postantibiotic eras via three different activity stations, focusing on nursing, the search for new antibiotics and investigations into novel antimicrobials. The use of observers released the presenters from evaluation duties, enabling them to focus on their specific activities. Qualitative measures of audience engagement were combined with quantitative data.

Conclusions

The evaluation revealed that adult audiences can easily be absorbed into an activity—particularly if hands‐on—after a brief introduction.

Significance and Impact of the Study

This research demonstrates that hands‐on practical engagement with AMR can enable high‐level interaction and learning in an informal and enjoyable environment.     

Platinum coat color locus in the deer mouse

Platinum coat color in the deer mouse, Peromyscus maniculatus, is an autosomal recessive trait marking a locus, pt, distinct from silver (si), albino (c), blonde (bl), brown (b), and agouti (a). Platinum deer mice are conspicuously pale, with light ears and tail stripe. The pewter trait is allelic with and phenotypically identical to platinum, and represents an independent recurrence of this mutant. The rate of recoveries of coat color mutations from wild deer mice is consistent with available data for recurring mutation rates balanced by strong selection against the recessive phenotype.     

Imitator strategies

An imitator strategy in an evolutionary game is a pair (u, p) consisting of a conventional and generally-known strategy u (the personal strategy) and a probability p of using the opponent's personal strategy rather than one's own. The question of whether imitator strategies (p > 0) can be used to invade populations using conventional ESSs is explored, and is found to depend in part on the variability of strategy present in the initial population. Interior values of p (0 < p < 1) are found never to be optimal. Examples are used repeatedly to illustrate the theory. The imitator strategy is also compared with the successful Tit-for-Tat strategy considered in the Axelrod-Hamilton study of the Prisoner's dilemma.