The decision by a cell to enter a round of growth and division must be intimately coordinated with nutrient availability and its metabolic state. These metabolic and nutritional requirements, and the ...mechanisms by which they induce cell growth and proliferation, remain poorly understood. Herein, we report that acetyl-CoA is the downstream metabolite of carbon sources that represents a critical metabolic signal for growth and proliferation. Upon entry into growth, intracellular acetyl-CoA levels increase substantially and consequently induce the Gcn5p/SAGA-catalyzed acetylation of histones at genes important for growth, thereby enabling their rapid transcription and commitment to growth. Thus, acetyl-CoA functions as a carbon-source rheostat that signals the initiation of the cellular growth program by promoting the acetylation of histones specifically at growth genes.
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► A burst of acetyl-CoA production accompanies and triggers entry into growth ► SAGA dynamically acetylates its substrates in tune with acetyl-CoA levels ► SAGA is recruited to activate growth genes during growth ► Acetylated histones are highly enriched at growth genes, specifically during growth
The connective and supportive tissues constitute a considerable amount of the biomass in human and animal organisms. The aim of this book is to contribute to the understanding of the mutual ...relationship between the mechanical situation of tendons and ligaments and their inner structure.
Photodynamic therapy (PDT) is a clinical treatment in which a light‐absorbing drug called a photosensitizer (PS) is combined with light and molecular oxygen to generate cytotoxic singlet oxygen. PDT ...provides additional tissue selectivity compared to conventional chemotherapy as singlet oxygen is generated only in areas in which PS accumulates and that are simultaneously illuminated by a light source with sufficient irradiance and dose. Early PDT beacons built on this concept by adding an analyte‐responsive element that simultaneously turns on PDT and fluorescence, providing both an additional layer of selectivity and real‐time feedback of the PS′s activation state. More recent PDT beacons have expanded this idea, with new methods now available for sensing analytes, generating singlet oxygen, and reporting treatment status. In this Minireview, we consider developments in advanced activation strategies implemented in therapeutic and theranostic beacons.
Extreme specificity: Photodynamic therapy beacons are phototoxic drugs that are only cytotoxic upon tissue accumulation, analyte‐driven activation, and external illumination. Moreover, their cytotoxic state simultaneously provides optical feedback to monitor treatment. In this Minireview, recent developments on how these beacons are becoming smarter still are discussed.
Autophagy is a process of cellular self-digestion induced by various forms of starvation. Although nitrogen deficit is a common trigger, some yeast cells induce autophagy upon switch from a rich to ...minimal media without nitrogen starvation. We show that the amino acid methionine is sufficient to inhibit such non-nitrogen-starvation (NNS)-induced autophagy. Methionine boosts synthesis of the methyl donor, S-adenosylmethionine (SAM). SAM inhibits autophagy and promotes growth through the action of the methyltransferase Ppm1p, which modifies the catalytic subunit of PP2A in tune with SAM levels. Methylated PP2A promotes dephosphorylation of Npr2p, a component of a conserved complex that regulates NNS autophagy and other growth-related processes. Thus, methionine and SAM levels represent a critical gauge of amino acid availability that is sensed via the methylation of PP2A to reciprocally regulate cell growth and autophagy.
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•Iml1/Npr2/Npr3 complex regulates autophagy induced in response to limited methionine•Methionine inhibits autophagy and promotes growth through the methylation of PP2A•Methylation of PP2A is responsive to SAM levels and regulates phosphorylation of Npr2•Methionine may impact the phosphostatus of proteins and TORC1 substrates via PP2A
Yeast cells sense and respond to levels of cellular methionine through regulation of PP2A to control choices between autophagy and cell growth upstream of mTORC1.
Many questions about human genetic history can be addressed by examining the patterns of shared genetic variation between sets of populations. A useful methodological framework for this purpose ...isF-statistics that measure shared genetic drift between sets of two, three, and four populations and can be used to test simple and complex hypotheses about admixture between populations. This article provides context from phylogenetic and population genetic theory. I review how F-statistics can be interpreted as branch lengths or paths and derive new interpretations, using coalescent theory. I further show that the admixture tests can be interpreted as testing general properties of phylogenies, allowing extension of some ideas applications to arbitrary phylogenetic trees. The new results are used to investigate the behavior of the statistics under different models of population structure and show how population substructure complicates inference. The results lead to simplified estimators in many cases, and I recommend to replace F3 with the average number of pairwise differences for estimating population divergence.
The well-known Hall effect describes the transverse deflection of charged particles (electrons/holes) as a result of the Lorentz force. Similarly, it is intriguing to examine if quasi-particles ...without an electric charge, but with a topological charge, show related transverse motion. Magnetic skyrmions with a well-defined spin texture with a unit topological charge serve as good candidates to test this hypothesis. In spite of the recent progress made on investigating magnetic skyrmions, direct observation of the skyrmion Hall effect has remained elusive. Here, by using a current-induced spin Hall spin torque, we experimentally demonstrate the skyrmion Hall effect, and the resultant skyrmion accumulation, by driving skyrmions from the creep-motion regime (where their dynamics are influenced by pinning defects) into the steady-flow-motion regime. The experimental observation of transverse transport of skyrmions due to topological charge may potentially create many exciting opportunities, such as topological selection.
A continental system for forecasting bird migration Van Doren, Benjamin M; Horton, Kyle G
Science (American Association for the Advancement of Science),
09/2018, Letnik:
361, Številka:
6407
Journal Article
Recenzirano
Odprti dostop
Billions of animals cross the globe each year during seasonal migrations, but efforts to monitor them are hampered by the unpredictability of their movements. We developed a bird migration forecast ...system at a continental scale by leveraging 23 years of spring observations to identify associations between atmospheric conditions and bird migration intensity. Our models explained up to 81% of variation in migration intensity across the United States at altitudes of 0 to 3000 meters, and performance remained high in forecasting events 1 to 7 days in advance (62 to 76% of variation was explained). Avian migratory movements across the United States likely exceed 500 million individuals per night during peak passage. Bird migration forecasts will reduce collisions with buildings, airplanes, and wind turbines; inform a variety of monitoring efforts; and engage the public.
Dietary protein, particularly essential amino acids, is important in the adult diet to help the body repair and regenerate cells and is important in the diet of children and adolescents for growth ...and development. In recent years, consumers are becoming more diverse when choosing foods to consume. Specifically, there is an increase around the world in the population of people who choose to consume a non-meat diet, and eat non-meat foods as their source of protein.
This review focused on comparing nutrient density and nutritional value (based on US dollars) of meat products and non-meat foods high in protein. Twenty-five meat products (beef, pork, lamb, and poultry), six fish products, and eighteen non-meat foods were compared for nutrient composition. Nutrient composition information was used to assign value based on nutrient density. Nutrient cost was expressed in nutrients available per US dollar and prices were assessed from the USDA economic research service and the USDA agricultural marketing service when available, and with a marketplace assessment when information was unavailable otherwise.
Consideration needs to be made when replacing meat in the diet with non-meat foods, because most non-meat foods contain only 20–60% protein density of meat. Additionally, when protein cost was evaluated, meat and non-meat foods had a similar cost when expressed as grams of protein/US dollar. While the total amount of zinc and iron was similar in meat and some non-meat foods, more investigation of digestibility and availability of nutrients is warranted.
•Meat is an excellent source of protein, phosphorus, zinc, and iron.•High-protein replacements for meat contain 20–60% of the protein of meat products.•High-protein replacements for meat contain adequate phosphorus, iron, and zinc.•Meat is not necessarily cheaper than non-meat products in protein density per cost.•Seafood is generally more expensive than meat in nutrient density per cost.
Meat analogues, or plant-based products that simulate the properties of traditional meat products, have secured a position in the conversation of protein foods. Rapid growth of the meat analogue ...industry is occurring in the global food marketplace in both the retail and food service sectors. The purpose of this review was to investigate the ingredients used in the formulation of modern meat analogues, evaluate the nutrient specifications of modern meat analogue products, and then form a comparison with traditional meat products. Based on this investigation, it was determined – firstly, the ingredients used in the formulation of modern meat analogue products make these products fit under the classification of ultra-processed foods; and secondly, the nutrient specifications of popular meat analogue products can effectively simulate the nutrient specifications of the meat products they are attempting to simulate. Therefore, based on these findings, modern meat analogue products can offer roughly the same composition of nutrients as traditional meat products, albeit with many different ingredients and a high level of further processing.
Drivers of fatal bird collisions in an urban center Van Doren, Benjamin M.; Willard, David E.; Hennen, Mary ...
Proceedings of the National Academy of Sciences - PNAS,
06/2021, Letnik:
118, Številka:
24
Journal Article
Recenzirano
Odprti dostop
Significance
Collisions with built structures are an important source of bird mortality, killing hundreds of millions of birds annually in North America alone. Nocturnally migrating birds are ...attracted to and disoriented by artificial lighting, making light pollution an important factor in collision mortality, and there is growing interest in mitigating the impacts of light to protect migrating birds. We use two decades of data to show that migration magnitude, light output, and wind conditions are important predictors of collisions at a large building in Chicago and that decreasing lighted window area could reduce bird mortality by ∼60%. Our finding that extinguishing lights can reduce bird death has global implications for conservation action campaigns aimed at eliminating an important cause of bird mortality.
Millions of nocturnally migrating birds die each year from collisions with built structures, especially brightly illuminated buildings and communication towers. Reducing this source of mortality requires knowledge of important behavioral, meteorological, and anthropogenic factors, yet we lack an understanding of the interacting roles of migration, artificial lighting, and weather conditions in causing fatal bird collisions. Using two decades of collision surveys and concurrent weather and migration measures, we model numbers of collisions occurring at a large urban building in Chicago. We find that the magnitude of nocturnal bird migration, building light output, and wind conditions are the most important predictors of fatal collisions. The greatest mortality occurred when the building was brightly lit during large nocturnal migration events and when winds concentrated birds along the Chicago lakeshore. We estimate that halving lighted window area decreases collision counts by 11× in spring and 6× in fall. Bird mortality could be reduced by ∼60% at this site by decreasing lighted window area to minimum levels historically recorded. Our study provides strong support for a relationship between nocturnal migration magnitude and urban bird mortality, mediated by light pollution and local atmospheric conditions. Although our research focuses on a single site, our findings have global implications for reducing or eliminating a critically important cause of bird mortality.
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