We provide a kinetic characterization of (Na , K )-ATPase activity in a posterior gill microsomal fraction from a hololimnetic population of the diadromous Amazon River shrimp Sucrose density gradient centrifugation reveals two distinct membrane fractions showing considerable (Na , K )ATP-ase activity, but also containing other microsomal ATPases. Only a single immune-reactive (Na , K )-ATPase with M of ≈110 kDa is present that hydrolyzes ATP with V = 130.3 ± 4.8 nmol Pi min mg protein and K = 0.065 ± 0.00162 mmol L , exhibiting site-site interactions. Stimulation by Na (V = 127.5 ± 5.3 nmol Pi min mg protein , K = 5.3 ± 0.42 mmol L ), Mg (V = 130.6 ± 6.8 nmol Pi min mg protein , K = 0.33 ± 0.042 mmol L ), K (V = 126.7 ± 7.7 nmol Pi min mg protein , K = 0.65 ± 0.0079 mmol L ) and NH (V = 134.5 ± 8.6 nmol Pi min mg protein , K = 1.28 ± 0.44 mmol L ) also obeys cooperative kinetics. Ouabain (K = 0.18 ± 0.058 mmol L ) inhibits total ATPase activity by ≈70%. This study reveals considerable differences in the kinetic characteristics of the gill (Na , K )-ATPase in a hololimnetic population that appear to result from the adaptation of diadromous populations to different limnic habitats
Anaerobic digestion of sludge is considered to be one of the most appropriate technologies for energy production via conversion of organic matter into methane containing biogas. Biogas produced by anaerobic digestion of municipal wastewater sludge can be utilized as fuel to offset heat and electricity consumption of wastewater treatment facilities. Modeling can be used effectively to evaluate the impact of different process and operation variables on the performance of the treatment processes including complex ones such as anaerobic digestion. Therefore, the Anaerobic Digestion Model No. 1 (ADM1) was applied in order to evaluate the performance of a full-scale anaerobic sludge digester in this study. With the calibration of the most sensitive parameters used in the ADM1, model outputs corresponded well with the measured data obtained from the operation of the full-scale digester. The model was validated with the data acquired from the same anaerobic digester at a different operation period (360days) and simulation results successfully predicted the digester performance. The overall results of this study demonstrated that the ADM1 can be used as a very useful tool to simulate the digestion of mixed sludge generated from full-scale wastewater treatment plants under mesophilic conditions.
In the present work was characterized in abiotic and biotic systems, the droplet size of hexadecane (HXD) in emulsified form. Furthermore it was assessed the uptake of HXD in their both form emulsified (microscopic droplets) and free (macroscopic droplets), using a microbial consortium with the capacity of degrading oil. HXD in emulsified form includes microscopic droplets of 0.1 and 0.5 up to 0.7 μm. In the biotic experiments the kinetic parameters values were determined either by fitting to the Contois model the consumed data of HXD emulsified and by considering also the uptake rate of the free forms of HXD as independent of their own concentration. A comparison of the maximum specific HXD uptake rate ( ) of the oil-degrading consortium when consumes the two forms of HXD, shows to be 53 times greater for the emulsified HXD that for their free form, suggesting that consumption of HXD is realized mostly by the emulsified form. The specific transfer area decreases with the culture time due to that the HXD is emulsified and consumed by the microbial consortium, being the specific transfer area of emulsified forms (microscopic droplets) a parameter that must be considered in the design of biodegradation processes of insoluble organic pollutants.
Marine fish are considered a source of high quality proteins and fatty acids. However, the consumption of fish may pose a health risk as it may have potentially toxic elements in high concentrations. In this study we quantify the multielemental composition of muscle and fins for three species of commercial marine fish from Brazil: (Barracuda), (Common bigeye) and (Guri sea catfish). We then assessed the potential risk of fish consumption by means of a Provisional Hazard Indices. Amongst the elements detected in fish tissue were potentially toxic elements such as Ag, Ba, Cd, Cr and Hg. Concentration differences were species-specific, and affected by the species trophic level, morphological characteristics and feeding habits. Results suggest the higher the trophic level of the fish, the higher the risk of consumption. Caution is recommended for the frequent ingestion of high trophic level fish species in Brazil.
The growth, maintenance and lysis processes of Nitrobacter were characterised. A Nitrobacter culture was enriched in a sequencing batch reactor (SBR). Fluorescent in situ hybridisation showed that Nitrobacter constituted 73% of the bacterial population. Batch tests were carried out to measure the oxygen uptake rate and/or nitrite consumption rate when both nitrite and CO2 were in excess, and in the absence of either of these two substrates. The results obtained, along with the SBR performance data, allowed the determination of the maintenance coefficient and in situ cell lysis rate of Nitrobacter. Nitrobacter spends a significant amount of energy for maintenance, which varies considerably with the specific growth rate. At maximum growth, Nitrobacter consume nitrite at a rate of 0.042 mgN/mgCOD(biomass)center dot h for maintenance purposes, which increases more than threefold to 0.143 mgN/mgCOD(biomass)center dot h in the absence of growth. In the SBR, where Nitrobacter grew at 40% of its maximum growth rate, a maintenance coefficient of 0.113 mgN/mgCOD center dot h was found, resulting in 42% of the total amount of nitrite being consumed for maintenance. The above three maintenance coefficient values obtained at different growth rates appear to support the maintenance model proposed in Pirt (1982). The in situ lysis rate of Nitrobacter was determined to be 0.07/day under aerobic conditions at 22 C and pH 7.3. Further, the maximum specific growth rate of Nitrobacter was estimated to be 0.02/h (0.48/day). The affinity constant of Nitrobacter with respect to nitrite was determined to be 1.50 mgNO(2)(-)-N/L, independent of the presence or absence of CO2. (c) 2006 Wiley Periodicals, Inc.
Groundwater samples from a gasohol contaminated aquifer were analyzed to investigate the effects of nitrate injection on microbial communities associated with benzene, toluene, ethylbenzene and xylenes (BTEX) biodegradation. Real-time quantitative PCR was used to quantify total bacteria (16S rDNA), nitrate-, iron-, sulfate-reducing bacteria and methanogens. Anaerobic BTEX degradation potential was assessed by targeting the gene which encodes for benzylsuccinate synthase (BSS), an enzyme that initiates the biodegradation of toluene and xylenes. Aerobic BTEX biodegradation potential was assessed by targeting the catabolic genes: toluene dioxygenase (TOD), naphthalene dioxygenase (NAH), ring hydroxylating monooxygenase (RMO), phenol hydroxylase (PHE), and/or biphenyl dioxygenase (BPH). 16S rDNA gene copies were higher (∼4 × 10 cells ml ) at the plume centerline coinciding with the highest concentrations of BTEX (∼26 mg-total l ) and ethanol (∼3 mg l ). Regions with high nitrate consumption coincided with the increased nitrate-reducing bacteria population. The establishment of Fe(III)-reducing zones were unlikely associated with bacteria belonging to genus. Sulfate-reducing bacteria and methanogens were not detected corroborating with the geochemical footprints. Nitrate did not stimulate the fortuitous growth of anaerobic BTEX degraders as indicated by the absence of bssA amplification. Nitrate alleviated the high biological oxygen demand (BOD) associated with BTEX and ethanol biodegradation thus maintaining microaerophilic niche that supported the growth of aerobic BTEX degraders as indicated by the presence of PHE gene copy numbers (∼2 × 10 PHE gene copies ml ). Among the genes tested, the non-functional 16S rDNA showed significant correlation ( = 0.94; < 0.05) with BTEX (but not ethanol) first-order ( ′) biodegradation rates. Further investigations are required, however, to validate qPCR accuracy and reliability to estimate contaminants removal rates for a wide range of contaminated sites. ► Microbial characterization was performed in BTEX and ethanol contaminated groundwater. ► Nitrate injection alleviated the consumption of oxygen during ethanol and BTEX biodegradation. ► Microaerophilic conditions supported hydroxylases harboring BTEX-degrading bacteria. ► Biomarker 16S rDNA gene correlated significantly with in situ BTEX removal rates.
This study aimed to evaluate the effects of 01 on quality parameters of Minas Frescal cheese and to investigate the hematological and clinical effects of its regular consumption on hypertensive overweighed women (n = 30, 50 g, 28 days). Microbiological (lactic acid bacteria and probiotic counts), physicochemical parameters (proximate composition, pH, proteolysis, organic acid levels, and fatty acid profile), water mobility (TD-NMR), bioactivity [antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activity], and microstructure were evaluated. The addition of 01 (10 CFU/g) did not change the proximate composition and the microstructure of the cheeses, while a more suitable fatty acid profile, lower pH, and higher antioxidant and ACE inhibitory activities, proteolysis and organic acid levels were observed. 01 improved the total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, triacylglycerides, diastolic and systolic pressure, hemoglobin, and hematocrit count of the hypertensive overweighed women.
The ST riatal‐Enriched protein tyrosine Phosphatase 61 ( STEP 61 ) inhibits the activity of the tyrosine kinase Fyn and dephosphorylates the GluN2B subunit of the NMDA receptor, whereas the protein kinase A phosphorylation of STEP 61 inhibits the activity of the phosphatase (Pharmacol. Rev. , 64, , p. 65). Previously, we found that ethanol activates Fyn in the dorsomedial striatum ( DMS ) leading to GluN2B phosphorylation, which, in turn, underlies the development of ethanol intake ( J. Neurosci., 30, , p. 10187). Here, we tested the hypothesis that inhibition of STEP 61 by ethanol is upstream of Fyn/GluN2B. We show that exposure of mice to ethanol increased STEP 61 phosphorylation in the DMS , which was maintained after withdrawal and was not observed in other striatal regions. Specific knockdown of STEP 61 in the DMS of mice enhanced ethanol‐mediated Fyn activation and GluN2B phosphorylation, and increased ethanol intake without altering the level of water, saccharine, quinine consumption or spontaneous locomotor activity. Together, our data suggest that blockade of STEP 61 activity in response to ethanol is sufficient for the activation of the Fyn/GluN2B pathway in the DMS . Being upstream of Fyn and GluN2B, inactive STEP 61 in the DMS primes the induction of ethanol intake. We show that ethanol‐mediated inhibition of STEP 61 in the DMS leads to Fyn activation and GluN2B phosphorylation. (a) Under basal conditions, active STEP 61 inhibits Fyn activity and dephosphorylates GluN2B. (b) Ethanol leads to the phosphorylation of STEP 61 on a specific inhibitory site. The inhibition of STEP 61 activity contributes to the activation of Fyn in response to ethanol, which, in turn, phosphorylates GluN2B. These molecular adaptations in the DMS promote ethanol drinking. We show that ethanol‐mediated inhibition of STEP 61 in the DMS leads to Fyn activation and GluN2B phosphorylation. (a) Under basal conditions, active STEP 61 inhibits Fyn activity and dephosphorylates GluN2B. (b) Ethanol leads to the phosphorylation of STEP 61 on a specific inhibitory site. The inhibition of STEP 61 activity contributes to the activation of Fyn in response to ethanol, which, in turn, phosphorylates GluN2B. These molecular adaptations in the DMS promote ethanol drinking.
Analogues of mitoQ and idebenone were synthesized to define the structural elements that support oxygen consumption in the mitochondrial respiratory chain. Eight analogues were prepared and fully characterized, then evaluated for their ability to support oxygen consumption in the mitochondrial respiratory chain. While oxygen consumption was strongly inhibited by mitoQ analogues in a chain length-dependent manner, modification of idebenone by replacement of the quinone methoxy groups by methyl groups (analogues – ) reduced, but did not eliminate, oxygen consumption. Idebenone analogues – also displayed significant cytoprotective properties toward cultured mammalian cells in which glutathione had been depleted by treatment with diethyl maleate.