Micropropagation of Hybrid Hellebores and their Endogenous Bacteria

Hellebores (Helleborus spp.) are winter-­‐flowering ornamental plants that are difficult to propagate in tissue culture. To improve the performance of hellebores during micropropagation, preliminary tests were done to standardize temperature and light quality. The effects of growth hormone type and concentration on plant multiplication were also assessed. Performance remained low, and plantlets often displayed visible contamination

Mapping the Fungal Battlefield: Using in situ Chemistry and Deletion Mutants to Monitor Interspecific Chemical Interactions Between Fungi

Fungi grow in competitive environments, and to cope, they have evolved strategies, such as the ability to produce a wide range of secondary metabolites. This begs two related questions. First, how do secondary metabolites influence fungal ecology and interspecific interactions? Second, can these interspecific interactions provide a way to “see” how fungi respond, chemically, within a competitive environment? To evaluate these, and to gain insight into the secondary metabolic arsenal fungi possess, we co-cultured Aspergillus fischeri, a genetically tractable fungus that produces a suite of mycotoxins, with Xylaria cubensis, a fungus that produces the fungistatic compound and FDA-approved drug, griseofulvin. To monitor and characterize fungal chemistry in situ, we used the droplet-liquid microjunction-surface sampling probe (droplet probe). The droplet probe makes a microextraction at defined locations on the surface of the co-culture, followed by analysis of the secondary metabolite profile via liquid chromatography-mass spectrometry. Using this, we mapped and compared the spatial profiles of secondary metabolites from both fungi in monoculture versus co-culture. X. cubensis predominantly biosynthesized griseofulvin and dechlorogriseofulvin in monoculture. In contrast, under co-culture conditions a deadlock was formed between the two fungi, and X. cubensis biosynthesized the same two secondary metabolites, along with dechloro-5′-hydroxygriseofulvin and 5′-hydroxygriseofulvin, all of which have fungistatic properties, as well as mycotoxins like cytochalasin D and cytochalasin C. In contrast, in co-culture, A. fischeri increased the production of the mycotoxins fumitremorgin B and verruculogen, but otherwise remained unchanged relative to its monoculture. To evaluate that secondary metabolites play an important role in defense and territory establishment, we co-cultured A. fischeri lacking the master regulator of secondary metabolism laeA with X. cubensis. We found that the reduced secondary metabolite biosynthesis of the ΔlaeA strain of A. fischeri eliminated the organism’s ability to compete in co-culture and led to its displacement by X. cubensis. These results demonstrate the potential of in situ chemical analysis and deletion mutant approaches for shedding light on the ecological roles of secondary metabolites and how they influence fungal ecological strategies; co-culturing may also stimulate the biosynthesis of secondary metabolites that are not produced in monoculture in the laboratory

Reading and Ownership

First paragraph: ‘It is as easy to make sweeping statements about reading tastes as to indict a nation, and as pointless.’ This jocular remark by a librarian made in the Times in 1952 sums up the dangers and difficulties of writing the history of reading. As a field of study in the humanities it is still in its infancy and encompasses a range of different methodologies and theoretical approaches. Historians of reading are not solely interested in what people read, but also turn their attention to the why, where and how of the reading experience. Reading can be solitary, silent, secret, surreptitious; it can be oral, educative, enforced, or assertive of a collective identity. For what purposes are individuals reading? How do they actually use books and other textual material? What are the physical environments and spaces of reading? What social, educational, technological, commercial, legal, or ideological contexts underpin reading practices? Finding answers to these questions is compounded by the difficulty of locating and interpreting evidence. As Mary Hammond points out, ‘most reading acts in history remain unrecorded, unmarked or forgotten’. Available sources are wide but inchoate: diaries, letters and autobiographies; personal and oral testimonies; marginalia; and records of societies and reading groups all lend themselves more to the case-study approach than the historical survey. Statistics offer analysable data but have the effect of producing identikits rather than actual human beings. The twenty-first century affords further possibilities, and challenges, with its traces of digital reader activity, but the map is ever-changing

Schoolbooks and textbook publishing.

In this chapter the author looks at the history of schoolbooks and textbook publishing. The nineteenth century saw a rise in the school book market in Britain due to the rise of formal schooling and public examinations. Although the 1870 Education and 1872 (Scotland) Education Acts made elementary education compulsory for childern between 5-13 years old, it was not until the end of the First World War that some sort form of secondary education became compulsory for all children

Comparing Notes: Recording and Criticism

This chapter charts the ways in which recording has changed the nature of music criticism. It both provides an overview of the history of recording and music criticism, from the advent of Edison’s Phonograph to the present day, and examines the issues arising from this new technology and the consequent transformation of critical thought and practice

The 42nd Symposium Chromatographic Methods of Investigating Organic Compounds : Book of abstracts

The 42nd Symposium Chromatographic Methods of Investigating Organic Compounds : Book of abstracts. June 4-7, 2019, Szczyrk, Polan

Wider Still and Wider: British Music Criticism since the Second World War

This chapter provides the first historical examination of music criticism in Britain since the Second World War. In the process, it also challenges the simplistic prevailing view of this being a period of decline from a golden age in music criticism

Bioinformatic Strategies to Understand the Complexities of Medicinal Natural Product Mixtures

Compounds from natural sources, as well as those inspired by them, represent the majority of small molecule drugs on the market today. Plants, owing to their complex biosynthetic pathways, are poised to synthesize diverse secondary metabolites that selectively target biological macromolecules. Despite the vast chemical landscape of botanicals and other natural products, drug discovery programs from these sources have diminished due to the costly and time-consuming nature of standard practices and high rates of compound rediscovery. Additionally, natural product mixtures are incredibly complex, and the standard reductionist approaches often ignore the presence of combination effects such as synergy and antagonism. Bioinformatics tools can be used to integrate biological and chemical datasets, and statistical analyses of these datasets are broadly termed “biochemometrics.” Biochemometric approaches enable researchers to predict active constituents early in the fractionation process and to tailor isolation efforts toward the most biologically relevant compounds. Throughout the course of this project, bioinformatics approaches were used to (1) discover biologically active constituents from the botanical medicines, (2) develop and improve data filtering, data transformation, and model simplification parameters to optimize biochemometrics models, and (3) produce a new approach capable of predicting mixture constituents that contribute to synergy, additivity, and antagonism in complex mixtures. The first goal was achieved by applying bioassay-guided fractionation, biocheomometric selectivity ratio analysis, and molecular networking to comprehensively evaluate the antimicrobial activity of the botanical Angelica keiskei Koidzumi against Staphylococcus aureus. This approach enabled the identification of putative active constituents early in the fractionation process, and provided structural information for these compounds. A subset of chalcone analogs were prioritized for isolation, yielding antimicrobial compounds 4-hydroxyderricin, xanthoangelol, and xanthoangelol K. This approach successfully identified a low abundance compound (xanthoangelol K) that has not been previously reported to possess antimicrobial activity. Two studies were undertaken to achieve the second goal. First ,we demonstrated the effectiveness of hierarchical cluster analysis (HCA) of replicate injections (technical replicates) as a methodology to identify chemical interferents and reduce their contaminating contribution to metabolomics models. Pools of metabolites were prepared from the A. keiskei and analyzed in triplicate using ultraperformance liquid chromatography coupled to mass spectrometry (UPLC-MS). Before filtering, HCA failed to cluster replicates in the datasets. To identify contaminant peaks, we developed a filtering process that evaluated the relative peak area variance of each variable within triplicate injections. This filtering process identified 128 ions that did not show consistent peak area from injection to injection that likely originated from the UPLC-MS system. When interferents were removed, replicates clustered in all datasets, highlighting the importance of technical replication in mass spectrometry-based studies and providing tool for evaluating the effectiveness of data filtering prior to statistical analysis. As a follow up study, the impact of data acquisition and data processing parameters on selectivity ratio models were assessed using an inactive botanical mixture spiked with known antimicrobial compounds. Selectivity ratio models were used to identify active constituents that were intentionally added to the mixture, as well as an additional antimicrobial compound, randainal, which was masked by the presence of antagonists in the mixture. This study revealed that data processing approaches, particularly data transformation and model simplification tools using a variance cutoff, had significant impacts on the models produced, either masking or enhancing the ability to detect active constituents in samples. This study emphasized the importance of data processing for obtaining reliable information from metabolomics models and demonstrates the strengths and limitations of selectivity ratio analysis to comprehensively assess complex botanical mixtures. Often, analytical tools aimed to assess biological mixtures ascribe the activity to a few known components. Although researchers recognize this as an oversimplification, research methodologies to address this problem have not been developed. To overcome this and to achieve the third goal of this project, a new approach called Simplify was developed that can both identify mixture components that contribute to biological activity and characterize the nature of their interactions prior to isolation. As a test case, this approach was applied to the botanical Salvia miltiorrhiza and successfully utilized to identify both additive and synergistic compounds. These findings illustrate the efficacy of this approach for understanding how natural product mixtures work in concert and are expected to serve as a launching point for the comprehensive evaluation of mixtures in future studies

Processing, Export, and Identification of Novel Linear Peptides from Staphylococcus aureus

Here, we provide evidence indicating that S. aureus secretes small linear peptides into the environment via a novel processing and secretion pathway. The discovery of a specialized pathway for the production of small linear peptides and the identification of these peptides leads to several important questions regarding their role in S. aureus biology, most interestingly, their potential to act as signaling molecules. The observations in this study provide a foundation for further in-depth studies into the biological activity of small linear peptides in S. aureus.Staphylococcus aureus can colonize the human host and cause a variety of superficial and invasive infections. The success of S. aureus as a pathogen derives from its ability to modulate its virulence through the release, sensing of and response to cyclic signaling peptides. Here we provide, for the first time, evidence that S. aureus processes and secretes small linear peptides through a specialized pathway that converts a lipoprotein leader into an extracellular peptide signal. We have identified and confirmed the machinery for each step and demonstrate that the putative membrane metalloprotease Eep and the EcsAB transporter are required to complete the processing and secretion of the peptides. In addition, we have identified several linear peptides, including the interspecies signaling molecule staph-cAM373, that are dependent on this processing and secretion pathway. These findings are particularly important because multiple Gram-positive bacteria rely on small linear peptides to control bacterial gene expression and virulence