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BioEssays : News and Reviews in... Sep 1997A marked feature of eukaryotic programmed cell death is an early drop in mitochondrial transmembrane potential. This results from the opening of permeability transition... (Review)
Review
A marked feature of eukaryotic programmed cell death is an early drop in mitochondrial transmembrane potential. This results from the opening of permeability transition pores, which are composed of adenine nucleotide translocators and mitochondrial porins. The latter share striking similarities with bacterial porins, including down-regulation of their pore size by purine nucleotides), suggesting a common origin. The porins of some invasive bacteria play a crucial role during their accommodation inside the host cell and this coexistence resembles the endosymbiotic origin of mitochondria. The above observations suggest that early in eukaryotic evolution, former invaders may have used porin-type channels to enter their host and to induce its death when the levels of its cytoplasmic purine nucleotides were dropped. The appearance of adenosine nucleotide translocators in the primitive eukaryotes, which permitted usage of the oxidative metabolism of the invaders, provided the basis for the permeability transition phenomena, now linked to the apoptotic process. Bcl-2-type molecules, being able to modulate the permeability transition pores by interaction with adenosine nucleotide translocators, may have played an essential role in conferring a means of controlling apoptosis.
Topics: Aerobiosis; Apoptosis; Eukaryotic Cells
PubMed: 9297974
DOI: 10.1002/bies.950190913 -
Water Research Jun 2022In this study a mathematical framework was developed to describe aerobic granulation based on 6 main mechanisms: microbial selection, selective wasting, maximizing...
In this study a mathematical framework was developed to describe aerobic granulation based on 6 main mechanisms: microbial selection, selective wasting, maximizing transport of substrate into the biofilm, selective feeding, substrate type and breakage. A numerical model was developed using four main components; a 1D convection/dispersion model to describe the flow dynamics in a reactor, a reaction/diffusion model describing the essential conversions for granule growth, a setting model to track granules during settling and feeding, and a population model containing up to 100,000 clusters of granules to model the stochastic behaviour of the granulation process. With this approach the model can explain the dynamics of the granulation process observed in practice. This includes the presence of a lag phase and a granulation phase. Selective feeding was identified as an important mechanism that was not yet reported in literature. When aerobic granules are grown from activated sludge flocs, a lag phase occurs, in which not many granules are formed, followed by a granulation phase in which granules rapidly appear. The ratio of granule forming to non-granule forming substrate together with the feast/famine ratio determine if the transition from the lag phase to the granulation phase is successful. The efficiency of selective wasting and selective feeding both determine the rate of this transition. Brake-up of large granules into smaller well settling particles was shown to be an important source for new granules. The granulation process was found to be the combined result from all 6 mechanisms and if conditions for either one are not optimal, other mechanisms can, to some extent, compensate. This model provides a theoretical framework to analyse the different relevant mechanisms for aerobic granular sludge formation and can form the basis for a comprehensive model that includes detailed nutrient removal aspects.
Topics: Aerobiosis; Bioreactors; Sewage; Waste Disposal, Fluid
PubMed: 35413626
DOI: 10.1016/j.watres.2022.118365 -
Applied Biochemistry and Biotechnology Jul 2015Vinasse is the main liquid waste from ethanol production, and it has a considerable pollution potential. Biological treatment is a promising alternative to reduce its... (Comparative Study)
Comparative Study
Vinasse is the main liquid waste from ethanol production, and it has a considerable pollution potential. Biological treatment is a promising alternative to reduce its organic load. The aim of this study was to analyze the biodegradation of sugarcane juice vinasse in aerobic and anaerobic conditions. The content of carbohydrates, proteins and volatile fatty acids was evaluated. Vinasse samples showed a high biodegradability (>96.5 %) and low percentage of inert chemical oxygen demand (COD) (<3.2 %) in both aerobic and anaerobic conditions. The rates of substrate utilization were slightly higher in aerobic reactors, but COD stabilization occurred simultaneously in the anaerobic reactors, confirming its suitability for anaerobic digestion. Inert COD in anaerobic conditions was lower than in aerobic conditions. On the other hand, COD from metabolic products in the anaerobic reactors was higher than in the aerobic ones, indicating an increased release of soluble microbial products (SMPs) by anaerobic microorganisms. The results indicated that carbohydrates were satisfactorily degraded and protein-like substances were the major components remaining after biological degradation of vinasse.
Topics: Aerobiosis; Anaerobiosis; Biodegradation, Environmental; Biological Oxygen Demand Analysis; Bioreactors; Carbohydrates; Fatty Acids, Volatile; Glucose; Proteins; Saccharum; Solubility; Waste Disposal, Fluid
PubMed: 25957273
DOI: 10.1007/s12010-015-1653-8 -
Water Science and Technology : a... 2014Sludge management accounts for approximately 60% of the total wastewater treatment plant expenditure and laws for sludge disposal are becoming increasingly stringent,...
Sludge management accounts for approximately 60% of the total wastewater treatment plant expenditure and laws for sludge disposal are becoming increasingly stringent, therefore much consideration is required when designing a solids handling process. A membrane thickening aerobic digestion process integrates a controlled aerobic digestion process with pre-thickening waste activated sludge using membrane technology. This process typically features an anoxic tank, an aerated membrane thickener operating in loop with a first-stage digester followed by second-stage digestion. Membrane thickening aerobic digestion processes can handle sludge from any liquid treatment process and is best for facilities obligated to meet low total phosphorus and nitrogen discharge limits. Membrane thickening aerobic digestion processes offer many advantages including: producing a reusable quality permeate with minimal levels of total phosphorus and nitrogen that can be recycled to the head works of a plant, protecting the performance of a biological nutrient removal liquid treatment process without requiring chemical addition, providing reliable thickening up to 4% solids concentration without the use of polymers or attention to decanting, increasing sludge storage capacities in existing tanks, minimizing the footprint of new tanks, reducing disposal costs, and providing Class B stabilization.
Topics: Aerobiosis; Membranes, Artificial; Waste Management
PubMed: 24718344
DOI: 10.2166/wst.2014.051 -
Annals of Internal Medicine Nov 1986
Topics: Aerobiosis; Aging; Cardiovascular Physiological Phenomena; Humans; Oxygen Consumption; Physical Fitness
PubMed: 3767154
DOI: 10.7326/0003-4819-105-5-783 -
Bioresource Technology Apr 2015To improve cultivation efficiency for microalgae Spirulina platensis is related to increase its potential use as food source and as an effective alternative for CO2...
To improve cultivation efficiency for microalgae Spirulina platensis is related to increase its potential use as food source and as an effective alternative for CO2 fixation. The present work attempted to establish a technique, namely attached cultivation, for S. platensis. Laboratory experiments were made firstly to investigate optimal conditions on attached cultivation. The optimal conditions were found: 25 g m(-2) for initial inoculum density using electrostatic flocking cloth as substrata, light intensity lower than 200 μmol m(-2) s(-1), CO2 enriched air flow (0.5%) at a superficial aeration rate of 0.0056 m s(-1) in a NaHCO3-free Zarrouk medium. An outdoor attached cultivation bench-scale bioreactor was built and a 10d culture of S. platensis was carried out with daily harvesting. A high footprint areal biomass productivity of 60 g m(-2) d(-1) was obtained. The nutrition of S. platensis with attached cultivation is identical to that with conventional liquid cultivation.
Topics: Aerobiosis; Algal Proteins; Biofilms; Biomass; Bioreactors; Carbohydrates; Carbon Dioxide; Cell Culture Techniques; Lipids; Photons; Spirulina
PubMed: 25647023
DOI: 10.1016/j.biortech.2015.01.025 -
Research Quarterly For Exercise and... Mar 1980
Topics: Aerobiosis; Anaerobiosis; Glucose; Humans; Metabolism; Models, Biological; Oxygen Consumption
PubMed: 7394286
DOI: 10.1080/02701367.1980.10609285 -
The Science of the Total Environment Mar 2022The present investigation aimed at providing a novel approach to promote the rapid granulation and stability of aerobic granular sludge (AGS) in a continuous-flow...
Rapid granulation of aerobic granular sludge and maintaining its stability by combining the effects of multi-ionic matrix and bio-carrier in a continuous-flow membrane bioreactor.
The present investigation aimed at providing a novel approach to promote the rapid granulation and stability of aerobic granular sludge (AGS) in a continuous-flow membrane bioreactor (MBR). By operating two identical MBRs with or with no bio-carrier for 125 days, it was found that the combination of multi-ionic matrix and bio-carrier could promote the rapid formation and maintain the long-term stability of AGS. The primary AGS was first observed inside the reactor on day 14, and the mature AGS appeared soon and kept stable for more than 4 months (its average size still was about 800 μm on day 125). Suitable filling ratio of bio-carrier was beneficial to form a stable and regular circulating water flow inside, and adding divalent metal ions quickly reduced the negative charges of tiny sludge particles, which were two essential factors leading to the rapid granulation of AGS and maintaining its stability. The multi-ionic matrix not only enhanced the biological aggregation process, but also facilitated the expansion of the cultivated AGS into a new multi-habitat system of Mn-AGS, in which, complex microbial communities with rich bio-diversity robustly promoted the efficient removal of organic pollutants and nutrients.
Topics: Aerobiosis; Bioreactors; Ions; Sewage; Waste Disposal, Fluid
PubMed: 34968611
DOI: 10.1016/j.scitotenv.2021.152644 -
The Journal of Physiology Sep 2003
Topics: Aerobiosis; Blood Volume; Exercise; Humans; Hypotension, Orthostatic; Physical Fitness
PubMed: 12837932
DOI: 10.1113/jphysiol.2003.049205 -
Angewandte Chemie (International Ed. in... Mar 2015The copper-catalyzed aerobic oxidation of primary and secondary alcohols without an external N-oxide co-oxidant is described. The catalyst system is composed of a...
The copper-catalyzed aerobic oxidation of primary and secondary alcohols without an external N-oxide co-oxidant is described. The catalyst system is composed of a Cu/diamine complex inspired by the enzyme tyrosinase, along with dimethylaminopyridine (DMAP) or N-methylimidazole (NMI). The Cu catalyst system works without 2,2,6,6-tetramethyl-l-piperidinoxyl (TEMPO) at ambient pressure and temperature, and displays activity for un-activated secondary alcohols, which remain a challenging substrate for catalytic aerobic systems. Our work underscores the importance of finding alternative mechanistic pathways for alcohol oxidation, which complement Cu/TEMPO systems, and demonstrate, in this case, a preference for the oxidation of activated secondary over primary alcohols.
Topics: Aerobiosis; Alcohols; Catalysis; Copper; Cyclic N-Oxides
PubMed: 25677693
DOI: 10.1002/anie.201411483