Review: The Use of Real-Time Fluorescence Instrumentation to Monitor Ambient Primary Biological Aerosol Particles (PBAP)

Primary biological aerosol particles (PBAP) encompass many particle types that are derived from several biological kingdoms. These aerosol particles can be composed of both whole living units such as pollen, bacteria, and fungi, as well as from mechanically formed particles, such as plant debris. They constitute a significant proportion of the overall atmospheric particle load and have been linked with adverse health issues and climatic effects on the environment. Traditional methods for their analysis have focused on the direct capture of PBAP before subsequent laboratory analysis. These analysis types have generally relied on direct optical microscopy or incubation on agar plates, followed by time-consuming microbiological investigation. In an effort to address some of these deficits, real-time fluorescence monitors have come to prominence in the analysis of PBAP. These instruments offer significant advantages over traditional methods, including the measurement of concentrations, as well as the potential to simultaneously identify individual analyte particles in real-time. Due to the automated nature of these measurements, large data sets can be collected and analyzed with relative ease. This review seeks to highlight and discuss the extensive literature pertaining to the most commonly used commercially available real-time fluorescence monitors (WIBS, UV-APS and BioScout). It discusses the instruments operating principles, their limitations and advantages, and the various environments in which they have been deployed. The review provides a detailed examination of the ambient fluorescent aerosol particle concentration profiles that are obtained by these studies, along with the various strategies adopted by researchers to analyze the substantial data sets the instruments generate. Finally, a brief reflection is presented on the role that future instrumentation may provide in revolutionizing this area of atmospheric research. Keywords: PBAP; WIBS; UV-APS; BioScout; fluorescence; real-time; bioaerosols

Growth, processing, and optical properties of epitaxial Er_2O_3 on silicon

Erbium-doped materials have been investigated for generating and amplifying light in low-power chip-scale optical networks on silicon, but several effects limit their performance in dense microphotonic applications. Stoichiometric ionic crystals are a potential alternative that achieve an Er^(3+) density 100× greater. We report the growth, processing, material characterization, and optical properties of single-crystal Er_2O_3 epitaxially grown on silicon. A peak Er^(3+) resonant absorption of 364 dB/cm at 1535nm with minimal background loss places a high limit on potential gain. Using high-quality microdisk resonators, we conduct thorough C/L-band radiative efficiency and lifetime measurements and observe strong upconverted luminescence near 550 and 670 nm

Immunomodulation with IL-4Rα antisense oligonucleotide prevents respiratory syncytial virus-mediated pulmonary disease

Respiratory syncytial virus (RSV) causes significant morbidity and mortality in infants worldwide. Severe RSV infections in infants cause bronchiolitis, wheeze, and/or cough and significantly increase the risk for developing asthma. RSV pathogenesis is thought to be due to a Th2-type immune response initiated in response to RSV infection, specifically in the infant. Using a neonatal mouse system as an appropriate model for human infants, we sought to determine whether local inhibition of IL-4Rα expression during primary RSV infection in the neonate would prevent Th2-skewed responses to secondary RSV infection and improve longterm pulmonary function. To reduce IL-4Rα expression, antisense oligonucleotides (ASOs) specific for IL-4Rα were administered intranasally to neonatal mice at the time of primary infection. Mice were initially infected with RSV at 1 wk of age and were reinfected at 6 wk of age. Administration of IL-4Rα ASOs during primary RSV infection in neonatal mice abolished the pulmonary dysfunction normally observed following reinfection in the adult. This ablation of pulmonary dysfunction correlated with a persistent rebalancing of the Th cell compartment with decreased Th2 responses (i.e., reduced goblet cell hyperplasia, Th2 cells, and cytokine secretion) and increased Th1 responses (i.e., elevated Th1 cell numbers and type I Abs and cytokines). Our data support our hypothesis that a reduction in the Th2 immune response during primary infection in neonates prevents Th2-mediated pulmonary pathology initially and upon reinfection and further suggest that vaccine strategies incorporating IL-4Rα ASOs may be of significant benefit to infants. Copyright © 2010 by The American Association of Immunologists, Inc

The development and pilot testing of the Self-management Programme of Activity, Coping and Education for Chronic Obstructive Pulmonary Disease (SPACE for COPD)

Purpose: There is no independent standardized self-management approach available for chronic obstructive pulmonary disease (COPD). The aim of this project was to develop and test a novel self-management manual for individuals with COPD. Patients: Participants with a confirmed diagnosis of COPD were recruited from primary care. Methods: A novel self-management manual was developed with health care professionals and patients. Five focus groups were conducted with individuals with COPD (N = 24) during development to confirm and enhance the content of the prototype manual. The Self-management Programme of Activity, Coping and Education for Chronic Obstructive Pulmonary Disease (SPACE for COPD) manual was developed as the focus of a comprehensive self-management approach facilitated by health care professionals. Preference for delivery was initial face-to-face consultation with telephone follow-up. The SPACE for COPD manual was piloted with 37 participants in primary care. Outcome measures included the Self-Report Chronic Respiratory Questionnaire, Incremental Shuttle Walk Test, and Endurance Shuttle Walking Test (ESWT); measurements were taken at baseline and 6 weeks. Results: The pilot study observed statistically significant improvements for the dyspnea domain of the Self-Report Chronic Respiratory Questionnaire and ESWT. Dyspnea showed a mean change of 0.67 (95% confidence interval 0.23–1.11, P = 0.005). ESWT score increased by 302.25 seconds (95% confidence interval 161.47–443.03, P < 0.001). Conclusion: This article describes the development and delivery of a novel self-management approach for COPD. The program, incorporating the SPACE for COPD manual, appears to provoke important changes in exercise capacity and breathlessness for individuals with COPD managed in primary care

Doing gender locally: The importance of ‘place’ in understanding marginalised masculinities and young men’s transitions to ‘safe’ and successful futures

Observable anxieties have been developing about the position of boys and young men in contemporary society in recent years. This is expressed as a crisis of masculinity, in which place is often implicitly implicated, but is rarely considered for its role in the shaping of young men’s practices, trajectories and aspirations. Drawing on research conducted with young people who accessed a range of social care support services, this article argues that transition means different things for young men in different locales and that local definitions of masculinity are required to better understand young men’s lives and the opportunities available to them. The authors argue that home life, street life, individual neighbourhoods, regions and nations all shaped the young men’s identities and the practices they (and the staff working with them) drew on in order to create successful futures and ‘safe’ forms of masculinity. It is suggested that this place-based approach has the potential to re-shape the ‘crisis’ discourse surrounding masculinity and the anxieties associated with young men

Shotgun cholanomics of ileal fluid

In this study we have developed a rapid method for the shotgun analysis of bile acids in intestinal fluid. The method is semi-quantitative, and requires little sample preparation. Bile salts might contribute to the pathogenesis of Crohn's disease. In a pilot study we demonstrate the method by analysing the bile acid content of ileal fluid from seven Crohn's disease patients and three healthy controls. The dominant bile acids observed were di and/or trihydroxycholanoates, di- and/or trihydroxycholanoylglycines, di- and/or tri-hydroxycholanoyltaurines, monosulphated dihydroxycholanoates and monosulphated dihydroxycholanoylglycine. The method can be similarly applied to samples derived from other parts of the intestine

Structural mechanism underpinning cross-reactivity of a CD8(+) T-cell clone that recognizes a peptide derived from human telomerase reverse transcriptase

T-cell cross-reactivity is essential for effective immune surveillance but has also been implicated as a pathway to autoimmunity. Previous studies have demonstrated that T-cell receptors (TCRs) that focus on a minimal motif within the peptide are able to facilitate a high level of T-cell cross-reactivity. However, the structural database shows that most TCRs exhibit less focused antigen binding involving contact with more peptide residues. To further explore the structural features that allow the clonally expressed TCR to functionally engage with multiple peptide-major histocompatibility complexes (pMHCs), we examined the ILA1 CD8(+) T-cell clone that responds to a peptide sequence derived from human telomerase reverse transcriptase. The ILA1 TCR contacted its pMHC with a broad peptide binding footprint encompassing spatially distant peptide residues. Despite the lack of focused TCR-peptide binding, the ILA1 T-cell clone was still cross-reactive. Overall, the TCR-peptide contacts apparent in the structure correlated well with the level of degeneracy at different peptide positions. Thus, the ILA1 TCR was less tolerant of changes at peptide residues that were at, or adjacent to, key contact sites. This study provides new insights into the molecular mechanisms that control T-cell cross-reactivity with important implications for pathogen surveillance, autoimmunity, and transplant rejection

Engineering enhanced thermostability into the Geobacillus pallidus nitrile hydratase

Nitrile hydratases (NHases) are important biocatalysts for the enzymatic conversion of nitriles to industrially-important amides such as acrylamide and nicotinamide. Although thermostability in this enzyme class is generally low, there is not sufficient understanding of its basis for rational enzyme design. The gene expressing the Co-type NHase from the moderate thermophile, Geobacillus pallidus RAPc8 (NRRL B-59396), was subjected to random mutagenesis. Four mutants were selected that were 3 to 15-fold more thermostable than the wild-type NHase, resulting in a 3.4–7.6 ​kJ/mol increase in the activation energy of thermal inactivation at 63 ​°C. High resolution X-ray crystal structures (1.15–1.80 ​Å) were obtained of the wild-type and four mutant enzymes. Mutant 9E, with a resolution of 1.15 ​Å, is the highest resolution crystal structure obtained for a nitrile hydratase to date. Structural comparisons between the wild-type and mutant enzymes illustrated the importance of salt bridges and hydrogen bonds in enhancing NHase thermostability. These additional interactions variously improved thermostability by increased intra- and inter-subunit interactions, preventing cooperative unfolding of α-helices and stabilising loop regions. Some hydrogen bonds were mediated via a water molecule, specifically highlighting the significance of structured water molecules in protein thermostability. Although knowledge of the mutant structures makes it possible to rationalize their behaviour, it would have been challenging to predict in advance that these mutants would be stabilising.The Royal Society (UK) and the National Research Foundation (South Africa) in the form of a Collaborative Research Project grant; a UK Global Challenge Research Fund grant: START- Synchrotron Techniques for African Research and Technology.https://www.sciencedirect.com/journal/current-research-in-structural-biologyhj2023BiochemistryGeneticsMicrobiology and Plant Patholog

Functional role of T-cell receptor nanoclusters in signal initiation and antigen discrimination

Antigen recognition by the T-cell receptor (TCR) is a hallmark of the adaptive immune system. When the TCR engages a peptide bound to the restricting major histocompatibility complex molecule (pMHC), it transmits a signal via the associated CD3 complex. How the extracellular antigen recognition event leads to intracellular phosphorylation remains unclear. Here, we used single-molecule localization microscopy to quantify the organization of TCR–CD3 complexes into nanoscale clusters and to distinguish between triggered and nontriggered TCR–CD3 complexes. We found that only TCR–CD3 complexes in dense clusters were phosphorylated and associated with downstream signaling proteins, demonstrating that the molecular density within clusters dictates signal initiation. Moreover, both pMHC dose and TCR–pMHC affinity determined the density of TCR–CD3 clusters, which scaled with overall phosphorylation levels. Thus, TCR–CD3 clustering translates antigen recognition by the TCR into signal initiation by the CD3 complex, and the formation of dense signaling-competent clusters is a process of antigen discrimination

Australian spiny mountain crayfish and their temnocephalan ectosymbionts: an ancient association on the edge of coextinction?

Australian spiny mountain crayfish (Euastacus, Parastacidae) and their ecotosymbiotic temnocephalan flatworms (Temnocephalida, Platyhelminthes) may have co-occurred and interacted through deep time, during a period of major environmental change. Therefore, reconstructing the history of their association is of evolutionary, ecological, and conservation significance. Here, time-calibrated Bayesian phylogenies of Euastacus species and their temnocephalans (Temnohaswellia and Temnosewellia) indicate near-synchronous diversifications from the Cretaceous. Statistically significant cophylogeny correlations between associated clades suggest linked evolutionary histories. However, there is a stronger signal of codivergence and greater host specificity in Temnosewellia, which co-occurs with Euastacus across its range. Phylogeography and analyses of evolutionary distinctiveness (ED) suggest that regional differences in the impact of climate warming and drying had major effects both on crayfish and associated temnocephalans. In particular, Euastacus and Temnosewellia show strong latitudinal gradients in ED and, conversely, in geographical range size, with the most distinctive, northern lineages facing the greatest risk of extinction. Therefore, environmental change has, in some cases, strengthened ecological and evolutionary associations, leaving host-specific temnocephalans vulnerable to coextinction with endangered hosts. Consequently, the extinction of all Euastacus species currently endangered (75%) predicts coextinction of approximately 60% of the studied temnocephalans, with greatest loss of the most evolutionarily distinctive lineages