Control of Metal Nanocrystal Size Reveals Metal-Support Interface Role for Ceria Catalysts

Science ◽  
2013 ◽  
Vol 341 (6147) ◽  
pp. 771-773 ◽  
Author(s):  
Matteo Cargnello ◽  
Vicky V. T. Doan-Nguyen ◽  
Thomas R. Gordon ◽  
Rosa E. Diaz ◽  
Eric A. Stach ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Structure And Function ◽  
Nanocrystal Size ◽  
Model Systems ◽  
Group Viii ◽  
Metal Interface ◽  
Platinum Nanocrystals ◽  
Metal Support ◽  
Ceria Catalysts ◽  
And Function

Interactions between ceria (CeO2) and supported metals greatly enhance rates for a number of important reactions. However, direct relationships between structure and function in these catalysts have been difficult to extract because the samples studied either were heterogeneous or were model systems dissimilar to working catalysts. We report rate measurements on samples in which the length of the ceria-metal interface was tailored by the use of monodisperse nickel, palladium, and platinum nanocrystals. We found that carbon monoxide oxidation in ceria-based catalysts is greatly enhanced at the ceria-metal interface sites for a range of group VIII metal catalysts, clarifying the pivotal role played by the support.

scholarly journals Chromatin-Mediated Regulation of Genome Plasticity in Human Fungal Pathogens

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 855 ◽  
Author(s):  
Buscaino
Keyword(s):  
Candida Albicans ◽  
Aspergillus Fumigatus ◽  
Cryptococcus Neoformans ◽  
Fungal Pathogens ◽  
Environmental Changes ◽  
Structure And Function ◽  
Model Systems ◽  
Genome Plasticity ◽  
And Function ◽  
Heterochromatin Structure

Human fungal pathogens, such as Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans, are a public health problem, causing millions of infections and killing almost half a million people annually. The ability of these pathogens to colonise almost every organ in the human body and cause life-threating infections relies on their capacity to adapt and thrive in diverse hostile host-niche environments. Stress-induced genome instability is a key adaptive strategy used by human fungal pathogens as it increases genetic diversity, thereby allowing selection of genotype(s) better adapted to a new environment. Heterochromatin represses gene expression and deleterious recombination and could play a key role in modulating genome stability in response to environmental changes. However, very little is known about heterochromatin structure and function in human fungal pathogens. In this review, I use our knowledge of heterochromatin structure and function in fungal model systems as a road map to review the role of heterochromatin in regulating genome plasticity in the most common human fungal pathogens: Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans.

scholarly journals Effects of obesity and weight loss on mitochondrial structure and function and implications for colorectal cancer risk

2019 ◽  
Vol 78 (3) ◽  
pp. 426-437 ◽  
Author(s):  
S. P. Breininger ◽  
F. C. Malcomson ◽  
S. Afshar ◽  
D. M. Turnbull ◽  
L. Greaves ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Weight Loss ◽  
Mitochondrial Dysfunction ◽  
Human Subjects ◽  
Human Colon ◽  
Structure And Function ◽  
Model Systems ◽  
Intentional Weight Loss ◽  
Mitochondrial Structure ◽  
And Function

Colorectal cancer (CRC) is the third most common cancer globally. CRC risk is increased by obesity, and by its lifestyle determinants notably physical inactivity and poor nutrition. Obesity results in increased inflammation and oxidative stress which cause genomic damage and contribute to mitochondrial dysregulation and CRC risk. The mitochondrial dysfunction associated with obesity includes abnormal mitochondrial size, morphology and reduced autophagy, mitochondrial biogenesis and expression of key mitochondrial regulators. Although there is strong evidence that increased adiposity increases CRC risk, evidence for the effects of intentional weight loss on CRC risk is much more limited. In model systems, energy depletion leads to enhanced mitochondrial integrity, capacity, function and biogenesis but the effects of obesity and weight loss on mitochondria in the human colon are not known. We are using weight loss following bariatric surgery to investigate the effects of altered adiposity on mitochondrial structure and function in human colonocytes. In summary, there is strong and consistent evidence in model systems and more limited evidence in human subjects that over-feeding and/or obesity result in mitochondrial dysfunction and that weight loss might mitigate or reverse some of these effects.

scholarly journals Alec Douglas Bangham. 10 November 1921 — 9 March 2010

2011 ◽  
Vol 57 ◽  
pp. 25-43 ◽  
Author(s):  
Sir Brian Heap ◽  
Gregory Gregoriadis
Keyword(s):  
Biological Membranes ◽  
Structure And Function ◽  
Artificial Lung ◽  
Model Systems ◽  
First Impressions ◽  
Animal Physiology ◽  
The Moment ◽  
And Function ◽  
Myelin Figures

A first meeting with Alec Bangham would leave an impression of a larger-than-life scientist with a penetrating curiosity and formidable features characteristically portrayed in the dramatic portrait painted by his nephew, Humphrey Bangham, which currently hangs in one of the Royal Society’s rooms. Or, as Jeffrey Watkins (FRS) experienced on reaching the Institute of Animal Physiology at Babraham in September 1963, ‘at the moment of my arrival he was avidly peering down a microscope and excitedly proclaiming the wonders of myelin figures as viewed through crossed polaroids … [and that] they might prove useful as model systems for the study of structure and function in biological membranes. It was decided that I should work immediately along these lines.’ So what were the formative events that led to these first impressions? What had contributed to the formation of a scientist who became known worldwide as the father of liposomes, the inventor of Artificial Lung Expanding Compound (ALEC)—and someone who never stopped thinking about membranes, surfactant, anaesthetics, cricket, vegetables, family and friends?

scholarly journals Srs2 and Pif1 as Model Systems for Understanding Sf1a and Sf1b Helicase Structure and Function

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1319
Author(s):  
Aviv Meir ◽  
Eric C. Greene
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nucleic Acids ◽  
Model Organism ◽  
Structure And Function ◽  
Model Systems ◽  
Genome Integrity ◽  
Repair Pathway ◽  
Domains Of Life ◽  
Nucleoprotein Complexes ◽  
And Function

Helicases are enzymes that convert the chemical energy stored in ATP into mechanical work, allowing them to move along and manipulate nucleic acids. The helicase superfamily 1 (Sf1) is one of the largest subgroups of helicases and they are required for a range of cellular activities across all domains of life. Sf1 helicases can be further subdivided into two classes called the Sf1a and Sf1b helicases, which move in opposite directions on nucleic acids. The results of this movement can range from the separation of strands within duplex nucleic acids to the physical remodeling or removal of nucleoprotein complexes. Here, we describe the characteristics of the Sf1a helicase Srs2 and the Sf1b helicase Pif1, both from the model organism Saccharomyces cerevisiae, focusing on the roles that they play in homologous recombination, a DNA repair pathway that is necessary for maintaining genome integrity.

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