PHYCOERYTHROCYANINS FROM Westiellopsis prolifica AND Nostoc rivulare: CHARACTERIZATION OF THE PHYCOVIOLOBILIN CHROMOPHORE IN BOTH STATES

Phycoerythrocyanin or fractions enriched in it have been isolated from the filamentous cyanobacteria, Westiellopsis prolifica ARM 365 and Nostoc rivulare ARM 212. Both show the photoreversible photochromism (difference maxima at 503 and 570 nm) characteristic of this pigment, which is related to the phycoviolobilin chromophore on the α-subunit. Native phycoerythrocyanin and its β-subunit show little if any reversible photochemistry in the 600–620 nm region, where the phycocyanobilin chromophores absorb maximally. Instead the phycocyanobilin chromophores are bleached irreversibly. At the same time, the data show that reversible photochemistry is a useful analytical tool to detect phycoerythrocyanin in cyanobacterial extracts. Fluorescence measurements indicate that: (i) the 510 nm absorbing isomer of the violobilin chromophore has only little fluorescence; and (ii) the energy transfer from the violobilin chromophores to the cyanin chromophores is efficient only in the 570 nm form

Rheology of Active-Particle Suspensions

We study the interplay of activity, order and flow through a set of coarse-grained equations governing the hydrodynamic velocity, concentration and stress fields in a suspension of active, energy-dissipating particles. We make several predictions for the rheology of such systems, which can be tested on bacterial suspensions, cell extracts with motors and filaments, or artificial machines in a fluid. The phenomena of cytoplasmic streaming, elastotaxis and active mechanosensing find natural explanations within our model.Comment: 3 eps figures, submitted to Phys Rev Let

FLUORESCENCE AND CIRCULAR DICHROISM STUDIES ON THE PHYCOERYTHROCYANINS FROM THE CYANOBACTERIUM

Two phycoerythrocyanin (PEC) fractions have been obtained from the phycobilisomes of the cyanobac-terium Westiellopsis prolifica ARM 365. They have been characterized by absorption, fluorescence and circular dichroism spectroscopy. One of them is spectroscopically similar to a PEC trimer known from other organisms. Whereas efficient energy transfer from its violin (α-84) to the cyanin (β-84, 155) chromophores is efficient in the trimer (αβ it is impeded after dissociation to the monomer (α,β). A second fraction of PEC which we earlier termed PEC(X) (Maruthi Sai et al., Photochem. Photobiol. 55,119–124, 1992), exhibited the spectral properties similar to that of the α-subunit of PEC from Mastigocladus laminosus. With this highly photoactive fraction, the circular dichroism spectra of the violobilin chromophore in both photoreversible states were obtained

Enrichment of clinically relevant organisms in spontaneous preterm delivered placenta and reagent contamination across all clinical groups in a large UK pregnancy cohort.

In this study differences in the placental microbiota of term and preterm deliveries from a large UK pregnancy cohort were studied using 16S targeted amplicon sequencing. The impact of contamination from DNA extraction, PCR reagents, as well as those from delivery itself were also examined. A total of 400 placental samples from 256 singleton pregnancies were analysed and differences investigated between spontaneous preterm, non-spontaneous preterm, and term delivered placenta. DNA from recently delivered placenta was extracted, and screening for bacterial DNA was carried out using targeted sequencing of the 16S rRNA gene on the Illumina MiSeq platform. Sequenced reads were analysed for presence of contaminating operational taxonomic units (OTUs) identified via sequencing of negative extraction and PCR blank samples. Differential abundance and between sample (beta) diversity metrics were then compared. A large proportion of the reads sequenced from the extracted placental samples mapped to OTUs that were also found in negative extractions. Striking differences in the composition of samples were also observed, according to whether the placenta was delivered abdominally or vaginally, providing strong circumstantial evidence for delivery contamination as an important contributor to observed microbial profiles. When OTU and genus level abundances were compared between the groups of interest, a number of organisms were enriched in the spontaneous preterm cohort, including organisms that have been previously associated with adverse pregnancy outcomes, specifically Mycoplasma spp., and Ureaplasma spp.. However, analyses of overall community structure did not reveal convincing evidence for the existence of a reproducible 'preterm placental microbiome'. IMPORTANCE: Preterm birth is associated with both psychological and physical disabilities and is the leading cause of infant morbidity and mortality worldwide. Infection is known to be an important cause of spontaneous preterm birth, and recent research has implicated variation in the 'placental microbiome' with preterm birth risk. Consistent with previous studies, the abundance of certain clinically relevant species differed between spontaneous preterm and non-spontaneous preterm or term delivered placenta. These results support the view that a proportion of spontaneous preterm births have an intra-uterine infection component. However, an additional observation from this study was that a substantial proportion of reads sequenced were contaminating reads, rather than DNA from endogenous, clinically relevant species. This observation warrants caution in the interpretation of sequencing output from such low biomass samples as the placenta

Ozonolysis of α-pinene: parameterization of secondary organic aerosol mass fraction

Existing parameterizations tend to underpredict the α-pinene aerosol mass fraction (AMF) or yield by a factor of 2–5 at low organic aerosol concentrations (<5 µg m<sup>−3</sup>). A wide range of smog chamber results obtained at various conditions (low/high NO<sub>x</sub>, presence/absence of UV radiation, dry/humid conditions, and temperatures ranging from 15–40°C) collected by various research teams during the last decade are used to derive new parameterizations of the SOA formation from α-pinene ozonolysis. Parameterizations are developed by fitting experimental data to a basis set of saturation concentrations (from 10<sup>−2</sup> to 10<sup>4</sup> µg m<sup>−3</sup>) using an absorptive equilibrium partitioning model. Separate parameterizations for α-pinene SOA mass fractions are developed for: 1) Low NO<sub>x</sub>, dark, and dry conditions, 2) Low NO<sub>x</sub>, UV, and dry conditions, 3) Low NO<sub>x</sub>, dark, and high RH conditions, 4) High NO<sub>x</sub>, dark, and dry conditions, 5) High NO<sub>x</sub>, UV, and dry conditions. According to the proposed parameterizations the α-pinene SOA mass fractions in an atmosphere with 5 µg m<sup>−3</sup> of organic aerosol range from 0.032 to 0.1 for reacted α-pinene concentrations in the 1 ppt to 5 ppb range

Part of the team: Effecting change and sharing power in healthcare settings

This is the final version. Available on open access from The Beryl Institute via the DOI in this recordIn 2019, we, as a group of patients and researchers, were invited to rethink how the executive board received and responded to patient stories at a specific NHS hospital trust in the UK. Through an iterative series of meetings, we were able to co-identify common concerns and together develop a distinctive narrative framework for effecting change by sharing patient experiences. This narrative framework is designed to help patients position themselves as ‘part of their healthcare team,’ emphasising roles and responsibilities between patients and health practitioners to compare ideals with reality in patient experiences. While the project was promising, several factors led the hospital to withdraw from working with the group—including the COVID-19 pandemic and changes in key NHS staff. In this article, we report on key support structures and obstacles which influenced the project, as well as its outcomes and limitations, with a view to constructively informing future endeavours at other healthcare institutions. We offer concluding reflections on the significance of collective voice, accessibility, administrative support, and senior staff buy-in. We feel these reflections are especially important since the cumulative effects of austerity and the COVID-19 pandemic have made meaningful commitment to patient involvement significantly more challenging for healthcare institutions, both in the UK and beyond.Wellcome Trus