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Cultivation In Long-Term Simulated Microgravity Is Detrimental To Pyocyanin Production And Subsequent Biofilm Formation Ability Of \u3cem\u3ePseudomonas aeruginosa\u3c/em\u3e
Get PDFPseudomonas aeruginosa forms aggregates known as biofilms. Previous studies have shown that when P. aeruginosa is cultivated in space, thicker and structurally different biofilms are formed than from those grown on Earth. We investigated how microgravity, simulated in a laboratory setting, influenced the growth, colonization, and virulence potentials of a P. aeruginosa PA14 wild-type strain, as well as two surface attachment-defective (sad) mutants altered at crucial biofilm-forming steps: flgK and pelA. Using high-aspect ratio rotating-wall vessel (HARV) bioreactors, P. aeruginosa bacteria were grown to stationary phase under prolonged (6 days) exposure to simulated microgravity or normal gravity conditions. After the exposure, the capacity of the culture to form biofilms was measured. Additionally, pigment (pyocyanin) formed by each culture during the incubation was extracted and quantified. We demonstrate that the first prolonged exposure to low-shear modeled microgravity (LSMMG) and without nutrient replenishment significantly diminishes wild-type P. aeruginosa PA14 biofilm formation abilities after exposure and pyocyanin production during exposure, while the mutant strains exhibit differing outcomes for both properties
Population Age Structure Shapes Selection On Social Behaviour In A Long-Lived Insect
No full textSocial traits are expected to experience highly context-dependent selection, but we know little about the contextual factors that shape selection on social behaviours. We hypothesized that the fitness consequences of social interactions will depend on the age of social partners, and therefore that population age structure will shape evolutionary pressures on sociality. Here, we investigate the consequences of age variation at multiple levels of social organization for both individual fitness and sexual selection on social network traits. We experimentally manipulated the age composition of populations of the forked fungus beetle Bolitotherus cornutus, creating 12 replicate populations with either young or old age structures. We found that fitness is associated with variance in age at three different levels of organization: the individual, interacting social partners, and the population. Older individuals have higher reproductive success, males pay a fitness cost when they interact with old males and females achieve lower fitness in older populations. In addition to influencing fitness, population age structure also altered the selection acting on social network position in females. Female sociality is under positive selection only in old populations. Our results highlight age structure as an understudied demographic variable shaping the landscape of selection on social behaviour
N-Methyl Mesoporphorin IX, A Reporter On GQ-DNA, Forms A Dimer In Aqueous Solution
No full textN-methyl mesoporphyrin IX (NMM) has rapidly become a significant tool for the characterization of quadruplex DNA (GQ-DNA) structures. These novel DNA structures are of interest due to their enrichment in protooncogene sequences and telomeres [Kosiol 2021]. As NMM becomes a standard tool in the sub-field of GQ-DNA research, it becomes increasingly important to understand its behavior. NMM\u27s utility is based on a shift in absorbance from a max at 379 nm to a max at 400 nm in the presence of GQ binding partners, and fluorescence enhancement upon the presence of binding partners [Yett 2019]. In this work we present data showing that NMM, in aqueous solution, without GQ-DNA present, shows a concentration dependent shift in peak absorbance from 400 nm to 379 nm with increasing concentration. Analysis, using singular value decomposition (SVD), shows that this shift is consistent with NMM forming a dimer. In addition, NMM displays increasing fluorescence intensity with increasing temperature, consistent with fluorescence quenching in the dimer state. These data suggest that some of the attributes of NMM as a GQ-DNA probe may be due to the presence of GQ-DNA, and associated binding, changing the effective concentration of free NMM in solution
Exploring Equity, Diversity, And Inclusion In Computer Science Undergraduate Curricula
No full textOne of the less explored approaches to foster equity, diversity, and inclusion (EDI) in Computer Science (CS) is through changes to the curriculum. Despite sporadic work on the adoption of Culturally Responsive Computing (CRC) and Universal Design for Learning (UDL), the inclusion of equity-minded courses, or modifications on specific elements of the curriculum such as introductory programming courses, there has never been a wide exploration or adoption of a successful equity-minded undergraduate CS curriculum. In this work, we explore undergraduate CS curricula, with a special focus on upper division, lower division, and service courses (courses offered to non-CS students). For each group, we examine the design and adoption of successful equity-minded approaches, exploring fair access, motivation, engagement, and rigour
“Patriarchal Oil No-More”: Collaborative Memorials Of An Oil Spill Clean Up In Galicia, Spain
No full textCrystal Structure Analysis Of The Non-Canonical G-Rich DNA TET25 In Complex With PyDH2 As A Potential Anticancer Therapeutic
No full textGuanine quadruplexes (GQs) are non-canonical secondary DNA structures comprised of stabilized stacks of guanine tetrads (G-tetrad). GQs are involved in various biological processes and have been implicated in human diseases, notably cancer. Small molecule ligands can change the folding and stability of GQs. The ability of ligands to control the structure of GQs can be used to develop therapeutic treatments. Here, we analyze the crystal structure of telomeric DNA from Tetrahymena thermophila (TET25) in complex with the highly selective GQ ligand PyDH2. Structural and spectroscopic data indicate that TET25 alone adopts a mixture of three GQ conformations, the major of which is a hybrid four G-tetrad GQ. In the presence of PyDH2, TET25 refolds into an antiparallel GQ conformation. The TET25-PyDH2 antiparallel structure was crystallized and successfully solved using molecular replacement. The crystal structure revealed that PyDH2 intercalates between the second and third G-tetrads of the antiparallel conformation. This intercalation is unique and has only been observed for the second time. Typically, ligands interact with GQs via end-stacking with the terminal G-tetrad. This study has increased our understanding of how small molecule ligands interact and affect the structure of GQ, allowing for the design of more effective GQ binders
Intensional Functions
Get PDFFunctions in functional languages have a single elimination form—application—and cannot be compared, hashed, or subjected to other non-application operations. These operations can be approximated via defunctionalization: functions are replaced with first-order data and calls are replaced with invocations of a dispatch function. Operations such as comparison may then be implemented for these first-order data to approximate e.g. deduplication of continuations in algorithms such as unbounded searches. Unfortunately, this encoding is tedious, imposes a maintenance burden, and obfuscates the affected code. We introduce an alternative in intensional functions, a language feature which supports the definition of non-application operations in terms of a function’s definition site and closure-captured values. First-order data operations may be defined on intensional functions without burdensome code transformation. We give an operational semantics and type system and prove their formal properties. We further define intensional monads, whose Kleisli arrows are intensional functions, enabling monadic values to be similarly subjected to additional operations
Review Of Ballroom: A People\u27s History Of Dancing By H. French
No full textFrench (emer., Bath Spa Univ., UK; former head of the School of Architecture and Design at the Royal College of Art) has published several books on 20th-century urban housing. Her point of view in this volume is that of an amateur British ballroom dancer. Her overview of the history of social and competitive ballroom dance is centered in the UK, but she does give some attention to crosscurrents from the US, other European countries, and Australia. French’s chronicle begins in the early 20th century, when the creation of public ballrooms in Britain opened ballroom dancing access to a range of social classes. The author traces ballroom dance development and examines the ten standard dances. She considers influences of the architecture of ballrooms, clothing worn, music composed for the dances, and various individuals and organizations supporting and regulating British ballroom dance. Useful discussion of distinctions and dialogues between social and competition approaches to the form is included. Also covered, briefly, are the influences of television dance shows in the late 20th century and current practices. Numerous photos, illustrations, and charts enhance the text. Summing Up: Recommended. With reservations. Graduate students, researchers, faculty, professionals
Exploring N-H bond activation and C-H bond activation by Tripodal Tris(nitroxide) Aluminum and Gallium Complexes
Get PDFThe activation of H–X (X = O, N, C) bonds is a common primary step in introducing alcohols, amines, and hydrocarbons into catalytic processes used in various industries. Precious metal complexes are commonly used as catalysts to activate H–X bonds through formal metal-based oxidative addition. However, since precious metals are scarce, expensive, toxic, and environmentally harmful, developing non-precious metal coordination complexes for H–X bond activation is essential. As a result, we investigate the activation of O–H, N–H, and C–H bonds through tripodal tris(nitroxide) aluminum and gallium complexes to develop a green strategy for broad-based H–X bond activation. Past members of the Graves Group studied the reactivities of the tripodal tris(nitroxide) aluminum and gallium complexes with alcohols. They found out these complexes can activate O–H bonds, with both alcohol acidity and metal center lewis acidity affecting the reactivity of these complexes with alcohols. In this study, we investigated the reactivities of the tripodal tris(nitroxide) Al and Ga complexes with amines and hydrocarbons to determine whether these complexes can activate N–H and C–H bonds. If so, we aim to understand how substrate acidity and metal center lewis acidity affect these reactivities