Stimulation of phosphatidylinositol hydrolysis, protein kinase C translocation, and mitogen-activated protein kinase activity by bradykinin in rat ventricular myocytes: dissociation from the hypertrophic response.

In ventricular myocytes cultured from neonatal rat hearts, bradykinin (BK), kallidin or BK(1-8) [(Des-Arg9)BK] stimulated PtdinsP2 hydrolysis by 3-4-fold. EC50 values were 6 nM (BK), 2 nM (kallidin), and 14 microM [BK(1-8)]. BK or kallidin stimulated the rapid (less than 30 s) translocation of more than 80% of the novel protein kinase C (PKC) isoforms nPKC-delta and nPKC-epsilon from the soluble to the particulate fraction. EC50 values for nPKC-delta translocation by BK or kallidin were 10 and 2 nM respectively. EC50 values for nPKC-epsilon translocation by BK or kallidin were 2 and 0.6 nM respectively. EC50 values for the translocation of nPKC-delta and nPKC-epsilon by BK(1-8) were more than 5 microM. The classical PKC, cPKC-alpha, and the atypical PKC, nPKC-zeta, did not translocate. BK caused activation and phosphorylation of p42-mitogen-activated protein kinase (MAPK) (maximal at 3-5 min, 30-35% of p42-MAPK phosphorylated). p44-MAPK was similarly activated. EC50 values for p42/p44-MAPK activation by BK were less than 1 nM whereas values for BK(1-8) were more than 10 microM. The order of potency [BK approximately equal to kallidin > BK (1-8)] for the stimulation of PtdInsP2 hydrolysis, nPKC-delta and nPKC-epsilon translocation, and p42/p44-MAPK activities suggests involvement of the B2 BK receptor subtype. In addition, stimulation of all three processes by BK was inhibited by the B2BK receptor-selective antagonist HOE140 but not by the B1-selective antagonist Leu8BK(1-8). Exposure of cells to phorbol 12-myristate 13-acetate for 24 h inhibited subsequent activation of p42/p44-MAPK by BK suggesting participation of nPKC (and possibly cPKC) isoforms in the activation process. Thus, like hypertrophic agents such as endothelin-1 (ET-1) and phenylephrine (PE), BK activates PtdInsP2 hydrolysis, translocates nPKC-delta, and nPKC-epsilon, and activates p42/p44-MAPK. However, in comparison with ET-1 and PE, BK was only weakly hypertrophic as assessed by cell morphology and patterns of gene expression. This difference could not be attributed to dissimilarities between the duration of activation of p42/p44-MAPK by BK or ET-1. Thus activation of these signalling pathways alone may be insufficient to induce a powerful hypertrophic response.

Heterodinuclear Fe(III)Zn(II)-Bioinspired Complex Supported on 3-Aminopropyl Silica. Efficient Hydrolysis of Phosphate Diester Bonds

Presented herein is the synthesis and characterization of a new Fe(III)Zn(II) complex containing a Fe(III)-bound phenolate with a carbonyl functional group, which was anchored to 3-aminopropylfunctionalized silica as the solid support. The catalytic efficiency of the immobilized catalyst in the hydrolysis of 2,4-bis (dinitrophenyl) phosphate is comparable to the homogeneous reaction, and the supported catalyst can be reused for subsequent diester hydrolysis reactions.

In situ and simultaneous nanostructural and spectroscopic studies of ZnO nanoparticle and Zn-HDS formations from hydrolysis of ethanolic zinc acetate solutions induced by water

The simultaneous formation of nanometer sized zinc oxide (ZnO), and acetate zinc hydroxide double salt (Zn-HDS) is described. These phases, obtained using the sol-gel synthesis route based on zinc acetate salt in alcoholic media, were identified by direct characterization of the reaction products in solution using complementary techniques: nephelometry, in situ Small-Angle X-ray Scattering (SAXS), UV-Vis spectroscopy and Extended X-ray Absorption Fine Structures (EXAFS). In particular, the hydrolytic pathway of ethanolic zinc acetate precursor solutions promoted by addition of water with the molar ratio N = [H2O]/[Zn2+] = 0.05 was investigated in this paper. The aim was to understand the formation mechanism of ZnO colloidal suspension and to reveal the factors responsible for the formation of Zn-HDS in the final precipitates. The growth mechanism of ZnO nanoparticles is based on primary particle (radius approximate to 1.5 nm) rotation inside the primary aggregate (radius < 3.5 nm) giving rise to an epitaxial attachment of particles and then subsequent coalescence. The growth of second ZnO aggregates is not associated with the Otswald ripening, and could be associated with changes in equilibrium between solute species induced by the superficial etching of Zn-HDS particles at the advanced stage of kinetic.

Saccharification of Brazilian sisal pulp: evaluating the impact of mercerization on non-hydrolyzed pulp and hydrolysis products

Cultivation of sisal, a plant with a short growth cycle, is highly productive in Brazil. This work is part of extensive research in which sisal is valued. In these studies, sisal fibers are used in the preparation of bio-based composites and in the derivatization of the pulp, including posterior preparation of films. This study aimed to examine the use of sisal pulp in the production of bioethanol, which can potentially be a high efficiency process because of the cellulose content of this fiber. A previous paper addressed the hydrolysis of sisal pulp using sulfuric acid as a catalyst. In the present study, the influence of the mercerization process on the acid hydrolysis of sisal pulp was evaluated. Mercerization was achieved in a 20% wt NaOH solution, and the cellulosic pulp was suspended and vigorously mixed for 1, 2 and 3 h, at 50 A degrees C. The previously characterized mercerized pulps were hydrolyzed (100 A degrees C, 30% H2SO4, v/v), and the results are compared with those obtained for unmercerized pulp (described in a companion paper). The starting sample was characterized by viscometry, alpha-cellulose content, crystallinity index and scanning electron microscopy. During the reactions, aliquots were withdrawn, and the liquor was analyzed by HPLC. The residual pulps (non-hydrolyzed) were also characterized by the techniques described for the initial sample. The results revealed that pretreatment decreases the polyoses content as well as causes a decrease of up to 23% in the crystallinity and up to 21% in the average molar mass of cellulose after 3 h of mercerization. The mercerization process proved to be very important to achieve the final target. Under the same reaction conditions (30% and 100 A degrees C, 6 h), the hydrolysis of mercerized pulp generated yields of up to 50% more glucose. The results of this paper will be compared with the results of subsequent studies obtained using other acids, and enzymes, as catalysts.

Carbon isotope fractionation during calcium carbonate precipitation induced by urease-catalysed hydrolysis of urea

Stable carbon isotopic fractionation during calcium carbonate precipitation induced by urease-catalysed hydrolysis of urea was experimentally investigated in artificial water at a constant temperature of 30 degrees C. Carbon isotope fractionation during urea hydrolysis follows a Rayleigh distillation trend characterized by a C-13-enrichment factor of -20 to -22 parts per thousand. CaCO3 precipitate is up to 17.9 parts per thousand C-13-depleted relative to the urea substrate (-48.9 +/- 0.07 parts per thousand). Initial CaCO3 precipitate forms close to isotopic equilibrium with dissolved inorganic carbon. Subsequent precipitation occurs at -2 to -3 parts per thousand offset from isotopic equilibrium, suggesting that the initial delta C-13 value of CaCO3 is reset through dissolution followed by reprecipitation with urease molecules playing a role in offsetting the delta C-13 value of CaCO3 from isotopic equilibrium. Potentially, this isotopic systematics may provide a tool for the diagnosis of ureolytically-formed carbonate cements used as sealing agent. Moreover, it may serve as a basis to develop a carbon isotope tool for the quantification of ureolytically-induced CO2 sequestration. Finally, it suggests carbon isotope disequilibrium as a hallmark of past enzymatic activity in ancient microbial carbonate formation. (C) 2012 Elsevier B.V. All rights reserved.

Enzymatic hydrolysis and fermentation of ultradispersed wood particles after ultrasonic pretreatment

Background: A study of the correlation between the particle size of lignocellulosic substrates and ultrasound pretreatment on the efficiency of further enzymatic hydrolysis and fermentation to ethanol. Results: Themaximumconcentrations of glucose and, to a lesser extent, di- and trisaccharideswere obtained in a series of experiments with 48-h enzymatic hydrolysis of pine rawmaterials ground at 380–400 rpm for 30min. The highest glucose yield was observed at the end of the hydrolysis with a cellulase dosage of 10 mg of protein (204 ± 21 units CMCase per g of sawdust). The greatest enzymatic hydrolysis efficiency was observed in a sample that combined two-stage grinding at 400 rpm with ultrasonic treatment for 5–10 min at a power of 10 W per kg of sawdust. The glucose yield in this case (35.5 g glucose l−1) increased twofold compared to ground substrate without further preparation. Conclusions: Using a mechanical two-stage grinding of lignocellulosic raw materials with ultrasonication increases the efficiency of subsequent enzymatic hydrolysis and fermentation.

Dynamics of in vitro polymer degradation of polycaprolactone-based scaffolds : accelerated versus simulated physiological conditions

The increasing use of biodegradable devices in tissue engineering and regenerative medicine means it is essential to study and understand their degradation behaviour. Accelerated degradation systems aim to achieve similar degradation profiles within a shorter period of time, compared with standard conditions. However, these conditions only partially mimic the actual situation, and subsequent analyses and derived mechanisms must be treated with caution and should always be supported by actual long-term degradation data obtained under physiological conditions. Our studies revealed that polycaprolactone (PCL) and PCL-composite scaffolds degrade very differently under these different degradation conditions, whilst still undergoing hydrolysis. Molecular weight and mass loss results differ due to the different degradation pathways followed (surface degradation pathway for accelerated conditions and bulk degradation pathway for simulated physiological conditions). Crystallinity studies revealed similar patterns of recrystallization dynamics, and mechanical data indicated that the scaffolds retained their functional stability, in both instances, over the course of degradation. Ultimately, polymer degradation was shown to be chiefly governed by molecular weight, crystallinity susceptibility to hydrolysis and device architecture considerations whilst maintaining its thermodynamic equilibrium.

Acid hydrolysis of easily dispersed and microaggregate-derived silt- and clay-sized fractions to isolate resistant soil organic matter

The current paradigm in soil organic matter (SOM) dynamics is that the proportion of biologically resistant SOM will increase when total SOM decreases. Recently, several studies have focused on identifying functional pools of resistant SOM consistent with expected behaviours. Our objective was to combine physical and chemical approaches to isolate and quantify biologically resistant SOM by applying acid hydrolysis treatments to physically isolated silt- and clay-sized soil fractions. Microaggegrate-derived and easily dispersed silt- and clay-sized fractions were isolated from surface soil samples collected from six long-term agricultural experiment sites across North America. These fractions were hydrolysed to quantify the non-hydrolysable fraction, which was hypothesized to represent a functional pool of resistant SOM. Organic C and total N concentrations in the four isolated fractions decreased in the order: native > no-till > conventional-till at all sites. Concentrations of non-hydrolysable C (NHC) and N (NHN) were strongly correlated with initial concentrations, and C hydrolysability was found to be invariant with management treatment. Organic C was less hydrolysable than N, and overall, resistance to acid hydrolysis was greater in the silt-sized fractions compared with the clay-sized fractions. The acid hydrolysis results are inconsistent with the current behaviour of increasing recalcitrance with decreasing SOM content: while %NHN was greater in cultivated soils compared with their native analogues, %NHC did not increase with decreasing total organic C concentrations. The analyses revealed an interaction between biochemical and physical protection mechanisms that acts to preserve SOM in fine mineral fractions, but the inconsistency of the pool size with expected behaviour remains to be fully explained.

Does the acid hydrolysis-incubation method measure meaningful soil organic carbon pools?

The literature was reviewed and analyzed to determine the feasibility of using a combination of acid hydrolysis and CO2-C release during long-term incubation to determine soil organic carbon (SOC) pool sizes and mean residence times (MRTs). Analysis of 1100 data points showed the SOC remaining after hydrolysis with 6 M HCI ranged from 30 to 80% of the total SOC depending on soil type, depth, texture, and management. Nonhydrolyzable carbon (NHC) in conventional till soils represented 48% of SOC; no-till averaged 56%, forest 55%, and grassland 56%. Carbon dates showed an average of 1200 yr greater MRT for the NHC fraction than total SOC. Longterm incubation, involving measurement of CO2 evolution and curve fitting, measured active and slow pools. Active-pool C comprised 2 to 8% of the SOC with MRTs of days to months; the slow pool comprised 45 to 65% of the SOC and had MRTs of 10 to 80 yr. Comparison of field C-14 and (13) C data with hydrolysis-incubation data showed a high correlation between independent techniques across soil types and experiments. There were large differences in MRTs depending on the length of the experiment. Insertion of hydrolysis-incubation derived estimates of active (C-a), slow (C-s), and resistant Pools (C-r) into the DAYCENT model provided estimates of daily field CO2 evolution rates. These were well correlated with field CO2 measurements. Although not without some interpretation problems, acid hydrolysis-laboratory incubation is useful for determining SOC pools and fluxes especially when used in combination with associated measurements.

Workers’ UV exposure and the subsequent impact on skin

Introduction: Excessive exposure to ultraviolet (UV) radiation from sunlight is a causative factor in the development of skin damage and skin cancer. Little research has been undertaken into assessing the sun exposure linking to skin damage inside buildings or behind window glass. This project directly addressed this issue by aiming to assess the role that UV exposure has on skin damage for indoor workers and drivers. Methods: Measurements of personal UV exposure using UV sensitive polymer dosimeters were undertaken of 41 indoor workers and 3 professional drivers. Physical measurements of skin characteristics including skin pigmentation and UV induced skin photoaging were also determined. In addition, demographic information along with phenotypic characteristics, sun exposure and sun protection practice history, and history of skin damage were assessed through a questionnaire. Results: Indoor workers typically received low doses of UV radiation. However, one driver received a high dose (13J/cm2 UVA and 4.99 MED UVB on the arm). Age and years residing in Australia had a positive correlation with UV induced skin pigmentation. The number of major sunburns before 18 years was a risk factor for skin damage in adults. Those participants with fair skin, non-black hair and blue/green /blue-grey eye were more likely to have skin damage related to sun exposure. Conclusions: A person’s age, years residing in Australia, numbers of major sunburn, skin colour, hair colour and eye colour are important factors associated with the development of sun-related skin damage in workers. ‘Real World’ implications: 1. The number of major sunburns before 18 years was a risk factor for skin damage in adults. This clearly confirms the importance of early prevention. To protect the skin from extensive sun exposure for your generation should have significance for further prevention of skin damage. 2. It is unsurprising that age and years residing in Australia were associated with skin damage related UV radiation. Therefore, the general public should reinforce their sun protective measures and check skin regularly. 3. Drivers should take sun protective measures during their working hours between sunrise and sunset.

Modification and validation of a microwave-assisted digestion method for subsequent ICP-MS determination of selected heavy metals in sediment and fish samples in Agusan River, Philippines

This study investigated, validated, and applied the optimum conditions for a modified microwave assisted digestion method for subsequent ICP-MS determination of mercury, cadmium, and lead in two matrices relevant to water quality, that is, sediment and fish. Three different combinations of power, pressure, and time conditions for microwave-assisted digestion were tested, using two certified reference materials representing the two matrices, to determine the optimum set of conditions. Validation of the optimized method indicated better recovery of the studied metals compared to standard methods. The validated method was applied to sediment and fish samples collected from Agusan River and one of its tributaries, located in Eastern Mindanao, Philippines. The metal concentrations in sediment ranged from 2.85 to 341.06 mg/kg for Hg, 0.05 to 44.46 mg/kg for Cd and 2.20 to 1256.16 mg/kg for Pb. The results indicate that the concentrations of these metals in the sediments rapidly decrease with distance downstream from sites of contamination. In the selected fish species, the metals were detected but at levels that are considered safe for human consumption, with concentrations of 2.14 to 6.82 μg/kg for Hg, 0.035 to 0.068 μg/kg for Cd, and 0.019 to 0.529 μg/kg for Pb.