Application of yeast to study the tau and amyloid-β abnormalities of Alzheimer's disease

The major molecules associated with Alzheimer's disease, the phosphorylated protein tau and the 42 amino acid peptide, amyloid-β (Aβ), have recently been analyzed in yeast. These yeast studies have provided major new insights into the effects of tau and Aβ and, at the same time, offered new approaches to rapidly search for chemicals that may be involved in prevention of Alzheimer's disease. The following review summarizes the role of yeast and its contribution in Alzheimer's disease research, and highlights important studies that have been conducted in this model organism

Microbes at the extreme: mining with microbes

The use of microorganisms to recover precious and base metals from mineral ores and concentrates is called biomining, or biohydrometallurgical processing. Biomining occurs through the natural ability of certain microorganisms to catalyse reactions, leading to the solubilisation of metals from the minerals. This process is used today in commercial operations to recover copper, nickel, cobalt, zinc and uranium from complex ore

Finding chemopreventatives to reduce amyloid beta in yeast

[No abstract available

Exogenous folates stimulate growth and budding of Candida glabrata

Folate, vitamin B9, is well recognized as being essential for cell growth. The utilization of folate is common to all cells, but the source of it may be quite different. For example, mammalian cells depend on exogenous uptake of folates, while plants and microbes can synthesize them. There has been little consideration of uptake of folate in microbial cells, and studies on the effects of folates in mammalian cells, where conditions are restricted. This study shows that exogenous folates (folic acid or folinic acid), causes Candida glabrata cells suspended in water alone to undergo two cycles of cell division and to form multiple buds. The effect was limited to cells in the stationary phase and more profound in quiescent cells. These data indicate a novel response of yeast to folates that may increase the utility of yeast as a model to study folate transport and signaling

Mangrove and saltmarsh distribution mapping and land cover change assessment for south-eastern Australia from 1991 to 2015

Coastal wetland ecosystems, such as saltmarsh and mangroves, provide a wide range of important ecological and socio-economic services. A good understanding of the spatial and temporal distribution of these ecosystems is critical to maximising the benefits from restoration and conservation projects. We mapped mangrove and saltmarsh ecosystem transitions from 1991 to 2015 in south-eastern Australia, using remotely sensed Landsat data and a Random Forest classification. Our classification results were improved by the addition of two physical variables (Shuttle Radar Topographic Mission (SRTM), and Distance to Water). We also provide evidence that the addition of post-classification, spatial and temporal, filters improve overall accuracy of coastal wetlands detection by up to 16%. Mangrove and saltmarsh maps produced in this study had an overall User Accuracy of 0.82–0.95 and 0.81–0.87 and an overall Producer Accuracy of 0.71–0.88 and 0.24–0.87 for mangrove and saltmarsh, respectively. We found that mangrove ecosystems in south-eastern Australia have lost an area of 1148 ha (7.6%), whilst saltmarsh experienced an overall increase in coverage of 4157 ha (20.3%) over this 24-year period. The maps developed in this study allow local managers to quantify persistence, gains, and losses of coastal wetlands in south-eastern Australia

How Yeast Can Inform Us about Healthy Aging

Yeasts are eukaryotes like us, and they have informed us about our cellular and molecular biology for many decades. They are unicellular and live with 6000 genes, carrying out many of the same processes that we do. Like us, yeast exhibit the same processes of aging, with telomere shortening, loss of mitochondrial function, reduced proteostasis, reduced robustness and stress. Some of these attributes are associated with aging and may not be the cause of aging. Therefore, it is important to consider attributes that clearly affect the fitness of cells. We have constructed yeast with a reporter of deleterious protein turnover. It involves the Alzheimer's amyloid beta peptide fused to a green fluorescent protein to aid its visualization in living cells. The use of this reporter enables high throughput assays to find compounds that can improve proteostasis in older cells. Compounds, like simvastatin, improve proteostasis and improve health outcomes inageing. Stress and biochemicals may decrease health and lifespan. Yeast can be used to study aging, drugs and stress, and to search for compounds that improve robustness in cells affected by drugs or stress

Oxygen consumption and sulfate reduction in vegetated coastal habitats: Effects of physical disturbance

© 2019 Brodersen, Trevathan-Tackett, Nielsen, Connolly, Lovelock, Atwood and Macreadie. Vegetated coastal habitats (VCHs), such as mangrove forests, salt marshes and seagrass meadows, have the ability to capture and store carbon in the sediment for millennia, and thus have high potential for mitigating global carbon emissions. Carbon sequestration and storage is inherently linked to the geochemical conditions created by a variety of microbial metabolisms, where physical disturbance of sediments may expose previously anoxic sediment layers to oxygen (O 2 ), which could turn them into carbon sources instead of carbon sinks. Here, we used O 2 , hydrogen sulfide (H 2 S) and pH microsensors to determine how biogeochemical conditions, and thus aerobic and anaerobic metabolic pathways, vary across mangrove, salt marsh and seagrass sediments (case study from the Sydney area, Australia). We measured the biogeochemical conditions in the top 2.5 cm of surface (0-10 cm depth) and experimentally exposed deep sediments (> 50 cm depth) to simulate undisturbed and physically exposed sediments, respectively, and how these conditions may affect carbon cycling processes. Mangrove surface sediment exhibited the highest rates of O 2 consumption and sulfate (SO 42- ) reduction based on detailed microsensor measurements, with a diffusive O 2 uptake rate of 102 mmol O 2 m -2 d -1 and estimated sulfate reduction rate of 57 mmol S tot2- m -2 d -1 . Surface sediments (0-10 cm) across all the VCHs generally had higher O 2 consumption and estimated sulfate reduction rates than deeper layers (> 50 cm depth). O 2 penetration was < 4 mm for most sediments and only down to 1 mm depth in mangrove surface sediments, which correlated with a significantly higher percent organic carbon content (%C org ) within sediments originating from mangrove forests as compared to those from seagrass and salt marsh ecosystems. Additionally, pH dropped from 8.2 at the sediment/water interface to < 7-7.5 within the first 20 mm of sediment within all ecosystems. Prevailing anoxic conditions, especially in mangrove and seagrass sediments, as well as sediment acidification with depth, likely decreased microbial remineralisation rates of sedimentary carbon. However, physical disturbance of sediments and thereby exposure of deeper sediments to O 2 seemed to stimulate aerobic metabolism in the exposed surface layers, likely reducing carbon stocks in VCHs

Isolation of the Pneumocystis carinii dihydrofolate synthase gene and functional complementation in Saccharomyces cerevisiae

The Pneumocystis carinii gene encoding the enzyme dihydrofolate synthase (DHFS), which is involved in the essential biosynthesis of folates, was isolated from clones of the Pneumocystis genome project, and sequenced. The deduced P. carinii DHFS protein shares 38% and 35% identity with DHFS of Schizosaccharomyces pombe and Saccharomyces cerevisiae, respectively. P. carinii DHFS expressed from a plasmid functionally complemented a S. cerevisiae mutant with no DHFS. Comparison of available DHFSs with highly similar folylpolyglutamate synthases allowed the identification of potential signatures responsible for the specificities of these two classes of enzymes. The results open the way to experimentally analyse the structure and function of P. carinii mono-functional enzyme DHFS, to investigate a possible role of DHFS in the resistance to antifolates of P. jirovecii, the species infecting specifically humans, and to develop a new class of antifolates

Commentary: Evaluating the role of seagrass in Cenozoic CO2 variations

[No abstract available

Addressing calcium carbonate cycling in blue carbon accounting

Scientific Significance Statement There is considerable interest in measuring the capacity of the world\u27s ecosystems to trap and store excess atmospheric carbon dioxide to mitigate human‐induced climate change. Blue carbon describes the carbon storage potential of vegetated coastal ecosystems including tidal marshes, mangroves, and seagrasses. Efforts are now underway to include blue carbon in global carbon offset schemes by managing these ecosystems to enhance carbon sequestration by focusing on their effect on organic carbon processing. However, it is unclear what role inorganic carbon processing in blue carbon ecosystems plays in their overall carbon sequestration. Here, we argue that there are key uncertainties that will need to be addressed before we can account for this important process to more accurately estimate carbon offsets in blue carbon ecosystems