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https://www.readbyqxmd.com/read/28646084/a-novel-mechanism-linked-to-cell-density-largely-controls-cell-division-in-synechocystis
#1
Alberto A Esteves-Ferreira, Masami Inaba, Toshihiro Obata, Antoine Fort, Gerard Fleming, Wagner L Araújo, Alisdair R Fernie, Ronan Sulpice
Many studies have investigated the various genetic and environmental factors regulating cyanobacterial growth. Here, we investigated the growth and metabolism of Synechocystis sp. PCC 6803, under different nitrogen sources, light intensities and CO2 concentrations. Cells grown on urea showed the highest growth rates. However, for all the conditions, the daily growth rates in batch cultures decreased steadily over time, and stationary phase was obtained with similar cell densities. Unexpectedly, metabolic and physiological analyses showed that growth rates during log phase were not primarily controlled by the availability of photoassimilates...
June 23, 2017: Plant Physiology
https://www.readbyqxmd.com/read/28644830/optimal-chemotactic-responses-in-stochastic-environments
#2
Martin Godány, Bhavin S Khatri, Richard A Goldstein
Although the "adaptive" strategy used by Escherichia coli has dominated our understanding of bacterial chemotaxis, the environmental conditions under which this strategy emerged is still poorly understood. In this work, we study the performance of various chemotactic strategies under a range of stochastic time- and space-varying attractant distributions in silico. We describe a novel "speculator" response in which the bacterium compare the current attractant concentration to the long-term average; if it is higher then they tumble persistently, while if it is lower than the average, bacteria swim away in search of more favorable conditions...
2017: PloS One
https://www.readbyqxmd.com/read/28642498/uptake-and-metabolism-of-arginine-impact-plasmodium-development-in-the-liver
#3
Patrícia Meireles, António M Mendes, Rita I Aroeira, Bryan C Mounce, Marco Vignuzzi, Henry M Staines, Miguel Prudêncio
Prior to infecting erythrocytes and causing malaria symptoms, Plasmodium parasites undergo an obligatory phase of invasion and extensive replication inside their mammalian host's liver cells that depends on the parasite's ability to obtain the nutrients it requires for its intra-hepatic growth and multiplication. Here, we show that L-arginine (Arg) uptake through the host cell's SLC7A2-encoded transporters is essential for the parasite's development and maturation in the liver. Our data suggest that the Arg that is taken up is primarily metabolized by the arginase pathway to produce the polyamines required for Plasmodium growth...
June 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28642463/acute-loss-of-the-hepatic-endo-lysosomal-system-in-vivo-causes-compensatory-changes-in-iron-homeostasis
#4
Christoph Metzendorf, Anja Zeigerer, Sarah Seifert, Richard Sparla, Bahar Najafi, François Canonne-Hergaux, Marino Zerial, Martina U Muckenthaler
Liver cells communicate with the extracellular environment to take up nutrients via endocytosis. Iron uptake is essential for metabolic activities and cell homeostasis. Here, we investigated the role of the endocytic system for maintaining iron homeostasis. We specifically depleted the small GTPase Rab5 in the mouse liver, causing a transient loss of the entire endo-lysosomal system. Strikingly, endosome depletion led to a fast reduction of hepatic iron levels, which was preceded by an increased abundance of the iron exporter ferroportin...
June 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28641600/the-influence-of-food-consumption-and-socio-economic-factors-on-the-relationship-between-zinc-and-iron-intake-and-status-in-a-healthy-population
#5
Marija Knez, Marina Nikolic, Milica Zekovic, James Cr Stangoulis, Mirjana Gurinovic, Maria Glibetic
OBJECTIVE: To examine Zn and Fe nutritional status of a healthy population by means of anthropometric, dietary and biochemical measurements and to investigate the relationship of usual Zn and Fe dietary intakes to Zn and Fe status. In addition, to examine the impact of food choices and socio-economic factors on Fe and Zn dietary intakes and status with the aim to identify groups at risk of dietary deficiency and suggest factors that may influence the status of these nutrients. DESIGN: Food consumption was assessed by 24 h recall questionnaires...
June 23, 2017: Public Health Nutrition
https://www.readbyqxmd.com/read/28639406/controlling-cyanobacterial-harmful-blooms-in-freshwater-ecosystems
#6
Hans W Paerl
Cyanobacteria's long evolutionary history has enabled them to adapt to geochemical and climatic changes, and more recent human and climatic modifications of aquatic ecosystems, including nutrient over-enrichment, hydrologic modifications, and global warming. Harmful (toxic, hypoxia-generating, food web altering) cyanobacterial bloom (CyanoHAB) genera are controlled by the synergistic effects of nutrient (nitrogen and phosphorus) supplies, light, temperature, water residence/flushing times, and biotic interactions...
June 21, 2017: Microbial Biotechnology
https://www.readbyqxmd.com/read/28638821/the-tor-signaling-pathway-in-spatial-and-temporal-control-of-cell-size-and-growth
#7
REVIEW
Suam Gonzalez, Charalampos Rallis
Cell size is amenable by genetic and environmental factors. The highly conserved nutrient-responsive Target of Rapamycin (TOR) signaling pathway regulates cellular metabolic status and growth in response to numerous inputs. Timing and duration of TOR pathway activity is pivotal for both cell mass built up as well as cell cycle progression and is controlled and fine-tuned by the abundance and quality of nutrients, hormonal signals, growth factors, stress, and oxygen. TOR kinases function within two functionally and structurally discrete multiprotein complexes, TORC1 and TORC2, that are implicated in temporal and spatial control of cell size and growth respectively; however, recent data indicate that such functional distinctions are much more complex...
2017: Frontiers in Cell and Developmental Biology
https://www.readbyqxmd.com/read/28638389/recognition-of-orobanche-cumana-below-ground-parasitism-through-physiological-and-hyper-spectral-measurements-in-sunflower-helianthus-annuus-l
#8
Amnon Cochavi, Tal Rapaport, Tania Gendler, Arnon Karnieli, Hanan Eizenberg, Shimon Rachmilevitch, Jhonathan E Ephrath
Broomrape (Orobanche and Phelipanche spp.) parasitism is a severe problem in many crops worldwide, including in the Mediterranean basin. Most of the damage occurs during the sub-soil developmental stage of the parasite, by the time the parasite emerges from the ground, damage to the crop has already been done. One feasible method for sensing early, below-ground parasitism is through physiological measurements, which provide preliminary indications of slight changes in plant vitality and productivity. However, a complete physiological field survey is slow, costly and requires skilled manpower...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28637856/how-to-get-the-most-bang-for-your-buck-the-evolution-and-physiology-of-nutrition-dependent-resource-allocation-strategies
#9
REVIEW
Enoch Ng'oma, Anna M Perinchery, Elizabeth G King
All organisms use resources to grow, survive and reproduce. The supply of these resources varies widely across landscapes and time, imposing ultimate constraints on the maximal trait values for allocation-related traits. In this review, we address three key questions fundamental to our understanding of the evolution of allocation strategies and their underlying mechanisms. First, we ask: how diverse are flexible resource allocation strategies among different organisms? We find there are many, varied, examples of flexible strategies that depend on nutrition...
June 28, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28637849/breaking-out-of-the-comfort-zone-el-ni%C3%A3-o-southern-oscillation-as-a-driver-of-trophic-flows-in-a-benthic-consumer-of-the-humboldt-current-ecosystem
#10
José M Riascos, Marco A Solís, Aldo S Pacheco, Manuel Ballesteros
The trophic flow of a species is considered a characteristic trait reflecting its trophic position and function in the ecosystem and its interaction with the environment. However, climate patterns are changing and we ignore how patterns of trophic flow are being affected. In the Humboldt Current ecosystem, arguably one of the most productive marine systems, El Niño-Southern Oscillation is the main source of interannual and longer-term variability. To assess the effect of this variability on trophic flow we built a 16-year series of mass-specific somatic production rate (P/B) of the Peruvian scallop (Argopecten purpuratus), a species belonging to a former tropical fauna that thrived in this cold ecosystem...
June 28, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28636919/monitoring-quantitative-ultrasound-parameter-changes-in-a-cell-pellet-model-of-cell-starvation
#11
Lauren A Wirtzfeld, Elizabeth S L Berndl, Gregory J Czarnota, Michael C Kolios
Although it has previously been shown that the spectral analysis of ultrasound backscatter data is sensitive to the cellular changes caused by apoptosis, the sensitivity of spectral analysis to oncosis or ischemic cell death had not previously been studied. Whereas many anticancer treatments induce apoptosis, others induce cell starvation, or oncosis. HT-29 colon adenocarcinoma cells were formed into pellets and covered in phosphate-buffered saline at room temperature for 56 h. The pellets were imaged every 8 h with high-frequency (55 MHz) ultrasound and the raw radio-frequency data processed...
June 20, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28635136/knockdown-of-tor-causing-ovarian-diapause-in-a-genetically-stable-brachypterous-strain-of-nilaparvata-lugens
#12
Fangzhou Liu, Kaiyin Li, Wanlun Cai, Jing Zhao, Yulan Zou, Hongxia Hua
Brown planthopper (BPH), Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), is one of the most damaging pests of rice crops. BPH is a migratory insect with a delayed ovarian development in migrants classified as reproductive diapause. The molecular mechanism of reproductive diapause remains unclear, although we suspect it might be regulated by one or more nutrient signaling pathways. The target of rapamycin (TOR) pathway regulates cell growth in response to nutritional information, which raised a hypothesis that TOR mediates BPH reproductive diapause...
June 20, 2017: Archives of Insect Biochemistry and Physiology
https://www.readbyqxmd.com/read/28634367/proteomic-analysis-reveals-large-amounts-of-decomposition-enzymes-and-major-metabolic-pathways-involved-in-algicidal-process-of-trametes-versicolor-f21a
#13
Xueyan Gao, Congyan Wang, Wei Dai, Shenrong Ren, Fang Tao, Xingbing He, Guomin Han, Wei Wang
A recent algicidal mode indicates that fungal mycelia can wrap and eliminate almost all co-cultivated algal cells within a short time span. However, the underlying molecular mechanism is rarely understood. We applied proteomic analysis to investigate the algicidal process of Trametes versicolor F21a and identified 3,754 fungal proteins. Of these, 30 fungal enzymes with endo- or exoglycosidase activities such as β-1,3-glucanase, α-galactosidase, α-glucosidase, alginate lyase and chondroitin lyase were significantly up-regulated...
June 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28633077/simplified-empirical-model-for-phosphorous-removal-in-a-facultative-wastewater-lagoon
#14
Saloni Vijay, Qiuyan Yuan
Nutrient removal in a facultative lagoon in Manitoba, Canada, was monitored from May 2015 to April 2016. According to the 12-month data, phosphorous concentration in the effluent did not meet the regulatory requirement. Various models have been developed to predict nitrogen removal from lagoon through the years; however, not much effort has been deployed to model phosphorous removal from lagoons. Therefore, this research aims to relate the lagoon phosphate removal to the volatile suspended solids (VSS), metal concentration, and detention time...
June 17, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28632984/aging-induced-changes-in-biochar-s-functionality-and-adsorption-behavior-for-phosphate-and-ammonium
#15
Shamim Mia, Feike A Dijkstra, Balwant Singh
Biochar, a form of pyrogenic carbon, can contribute to agricultural and environmental sustainability by increasing soil reactivity. In soils, biochar could change its role over time through alterations in its surface chemistry. However, a mechanistic understanding of the aging process and its role in ionic nutrient adsorption and supply remain unclear. Here, we aged a wood biochar (550 °C) by chemical oxidation with 5-15% H2O2 and investigated the changes in surface chemistry and the adsorption behavior of ammonium and phosphate...
June 20, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28631312/the-flow-and-fate-of-digestive-enzymes-in-the-field-cricket-gryllus-bimaculatus
#16
Joseph Woodring
The flow of enzymes, the ratio of bound to unbound enzymes, and their inactivation in the cricket Gryllus bimaculatus was studied. The digestive enzymes are forced forward into the crop by caecal contraction and then they are mixed with freshly chewed food and saliva, forming a crop-chyme. This chyme is blended by crop peristalsis, and periodic opening of the preproventricular valve (PPV) allows posterior movement into the proventriculus and further into the midgut. The contraction of the crop is modulated by Grybi-AST and Grybi-SK peptides, which are partially secreted by the caecal endocrine cells...
June 20, 2017: Archives of Insect Biochemistry and Physiology
https://www.readbyqxmd.com/read/28630330/annual-mass-drownings-of-the-serengeti-wildebeest-migration-influence-nutrient-cycling-and-storage-in-the-mara-river
#17
Amanda L Subalusky, Christopher L Dutton, Emma J Rosi, David M Post
The annual migration of ∼1.2 million wildebeest (Connochaetes taurinus) through the Serengeti Mara Ecosystem is the largest remaining overland migration in the world. One of the most iconic portions of their migration is crossing of the Mara River, during which thousands drown annually. These mass drownings have been noted, but their frequency, size, and impact on aquatic ecosystems have not been quantified. Here, we estimate the frequency and size of mass drownings in the Mara River and model the fate of carcass nutrients through the river ecosystem...
June 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28628817/dynamics-of-dissolved-nutrients-in-the-aquaculture-shrimp-ponds-of-the-min-river-estuary-china-concentrations-fluxes-and-environmental-loads
#18
Ping Yang, Derrick Y F Lai, Baoshi Jin, David Bastviken, Lishan Tan, Chuan Tong
Dissolved inorganic nutrients (NO2(-)-N, NO3(-)-N, NH4(+)-N, and PO4(3-)-P) play a critical role in the effective management of water quality and prevention of fish and shrimp diseases in aquaculture systems. In this study, dissolved inorganic nutrient concentrations in the water column and sediment porewater, and the fluxes across the sediment-water interface (SWI) were investigated in three intensive shrimp ponds with zero water exchange to examine nutrient cycling during the different growth stages of shrimps...
June 16, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28628360/genetic-risk-factors-for-folate-responsive-neural-tube-defects
#19
Anne M Molloy, Faith Pangilinan, Lawrence C Brody
Neural tube defects (NTDs) are the most severe congenital malformations of the central nervous system. The etiology is complex, with both genetic and environmental factors having important contributions. Researchers have known for the past two decades that maternal periconceptional use of the B vitamin folic acid can prevent many NTDs. Though this finding is arguably one of the most important recent discoveries in birth defect research, the mechanism by which folic acid exerts this benefit remains unknown. Research to date has focused on the hypothesis that an underlying genetic susceptibility interacts with folate-sensitive metabolic processes at the time of neural tube closure...
June 19, 2017: Annual Review of Nutrition
https://www.readbyqxmd.com/read/28628191/abiotic-and-biotic-factors-modulate-carrion-fate-and-vertebrate-scavenging-communities
#20
Kelsey L Turner, Erin F Abernethy, L Mike Conner, Olin E Rhodes, James C Beasley
Carrion is a valuable nutrient resource used by a diversity of vertebrates across the globe. However, vertebrate scavenging ecology remains an understudied area of science, especially in regards to how biotic and abiotic factors influence scavenging community composition. Here we elucidate how fundamental biotic and abiotic factors interact to modulate the efficiency and composition of vertebrate scavengers by investigating scavenging dynamics across a large gradient in carcass sizes and habitat types representative of many temperate ecosystems, as well as between two seasons reflecting differences in invertebrate activity...
June 19, 2017: Ecology
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