SOD Type Research Articles

Zn12O12 Cluster‐Based Materials with Enhancing Visible Light Absorption by Doping Alkaline Earth Metal Atoms: A First‐Principles Prediction

Zinc oxide (ZnO) is a promising semiconductor material in the field of photocatalysis due to its excellent electronic and optical properties. Due to its wide bandgap, ZnO cannot absorb visible light, which limits its photocatalytic performance. The current research is mainly to reduce the bandgap of wurtzite ZnO by doping different atoms, so as to enhance its visible light absorption, but the effect is limited. Under the framework of first‐principles calculation, three alkaline earth metal elements, Be, Mg, and Ca, are selected to dope the low‐energy sites in the cavities of Zn12O12 cluster‐assembled material (SOD type) with single and double atoms, respectively (equivalent to the doping concentration of 8.3% and 16.7%) using a combination of geometric optimization and molecular dynamics, and a stable new semiconductor material with direct bandgap less than 1 eV is obtained, which has excellent light absorption properties in the visible region. In addition, the reason for the bandgap reduction of doped materials is revealed by analyzing the energy band structures and the density of states. This work provides a new idea for the development of new photocatalytic material based on ZnO.

Fast synthesis of zeolitic imidazolate framework ZIF-94 using NaOH and recycling reagents

ZIF-94 is a zeolitic imidazolate framework with the same SOD type topology than ZIF-8 but with an aldehyde group functionalized organic ligand. This turns ZIF-94 less thermally stable than ZIF-8 but with interesting properties of water and carbon dioxide adsorption, making the former a material highly suitable for carbon capture technologies. In this work, an alternative procedure for the synthesis of ZIF-94 was developed based on the use of NaOH as deprotonator. Besides, the crystallization was carried out in a very short time (1–20 min) at room temperature while centrifuging at 10,000 rpm. This made possible the simultaneous crystallization and separation of the product material giving rise, together with the use of the inorganic deprotonator, to a very efficient process with crystallization yields higher than 65%. For the best conditions tested (crystallization-centrifugation time of 5 min), 66 ± 24 nm in particle size, highly crystalline ZIF-94 with 485 m2 g−1 of specific surface area was obtained at a crystallization yield of 66.9%. Similar properties were obtained for ZIF-94 when prepared from recycled reagents (solvent, ligand and Zn salt).

The distinctive roles played by the superoxide dismutases of the extremophile Acinetobactersp. Ver3

Acinetobacter sp. Ver3 is a polyextremophilic strain characterized by a high tolerance to radiation and pro-oxidants. The Ver3 genome comprises the sodB and sodC genes encoding an iron (AV3SodB) and a copper/zinc superoxide dismutase (AV3SodC), respectively; however, the specific role(s) of these genes has remained elusive. We show that the expression of sodB remained unaltered in different oxidative stress conditions whereas sodC was up-regulated in the presence of blue light. Besides, we studied the changes in the in vitro activity of each SOD enzyme in response to diverse agents and solved the crystal structure of AV3SodB at 1.34 Å, one of the highest resolutions achieved for a SOD. Cell fractionation studies interestingly revealed that AV3SodB is located in the cytosol whereas AV3SodC is also found in the periplasm. Consistently, a bioinformatic analysis of the genomes of 53 Acinetobacter species pointed out the presence of at least one SOD type in each compartment, suggesting that these enzymes are separately required to cope with oxidative stress. Surprisingly, AV3SodC was found in an active state also in outer membrane vesicles, probably exerting a protective role. Overall, our multidisciplinary approach highlights the relevance of SOD enzymes when Acinetobacterspp. are confronted with oxidizing agents.

Phase‐Controlled Synthesis of Zeolites from Sodium Aluminosilicate under OSDA/Solvent‐Free Conditions

AbstractOSDA/solvent‐free synthesis of zeolites is suitable for practical commercialization due to low environmental damage and low cost. However, only a few types of zeolites have been successfully synthesized by this method. In this study, ANA, CAN, GIS, SOD, FAU and LTA type zeolites were synthesized by the OSDA/solvent‐free synthesis method by changing the Si/Al ratio and crystallization temperature in detail. At higher Si/Al ratios, FAU, GIS and ANA type zeolites were obtained with an increase of crystallization temperature. Meanwhile, at lower Si/Al ratios, LTA, SOD and CAN type zeolites were obtained with an increase of crystallization temperature. It was found that zeolites with high T atom density were synthesized with an increase of the crystallization temperature; zeolite with a high T atomic density is more stable. This work reveals the correlation between the Si / Al ratio and the crystallization temperature in OSDA/solvent‐free synthesis of zeolites, which provides a clear guideline for the OSDA/solvent‐free synthesis of zeolites.

Extraction, Identification and Gene Cloning of Mn-SOD from Pleurotus tuber-regium

The manganese superoxide dismutase of Pleurotus tuber-regium was extracted and identified. The manganese superoxide dismutase (Mn-SOD) gene of P. tuber-regium was cloned from the mycelium of P.tuber-regium. Mn-SOD of P.tuber-regium was extracted by liquid nitrogen grinding, ultrasound, ammonium sulfate precipitation and dialysis. Mn-SOD activity of P. tuber-regium was determined by WST-8 method. SOD type of P. tuber-regium was identified by H2O2. Mn-SOD gene was cloned from P. tuber-regium by homologous cloning, rapid amplification of cDNA ends, fusion primers and nested PCR. Results showed that the activity of Mn-SOD of P. tuber-regium was 1.66 U. There was no significant difference between the enzyme treated with H2O2 and untreated, indicating that the main SOD in P. tuber-regium was Mn-SOD. PtMn-SOD was cloned and obtained. Its DNA sequence was 1025 bp in total, 663 bp in open reading frame and 220 amino acids were encoded. Sequence analysis and phylogenetic tree showed that PtMn-SOD was closely related to Pleurotus ostreatus (accession number:MH645359.1). It was predicted that the molecular weight of the protein was 24.54 kDa and the isoelectric point of the protein was 7.86. PtMn-SOD protein located in mitochondria and played a role in mitochondria.

Sodalite-type metal-organic zeolite with uncoordinated N-sites as potential anticancer drug 5-fluorouracil (5-FU) delivery platform

In this work, a SOD type metal-organic zeolite ZTIF-1 was used to entrap the anticancer drug 5-fluorouracil (5-FU). This material exhibited high capability for 5-FU with fast speed owing to its large surface area and uncoordinated N-heteroatom sites. These results suggest that ZTIF-1 could be a valuable platform for delivery of anti-cancer agents.

SERUM LEVEL OF ADVANCED OXIDATION PROTEIN PRODUCTS AND THE ACTIVITY OF SUPEROXIDE DISMUTASE AS THE MARKERS OF OXIDATIVE STRESS IN PATIENTS WITH CHRONIC HEART FAILURE

Aim.The present work was aimed at studying and analysing the serum level of advanced oxidation protein products (AOPPs) and the total superoxide dismutase activity (total SOD) in patients with chronic heart failure (CHF) with a preserved and low left ventricular ejection fraction, depending on the stage of the disease.Materials and methods.Patients with CHF (n=280) were divided into groups depending on the left ventricular ejection fraction (patients with a preserved and low left ventricular ejection fraction) and the stage of the disease (I–III). The control group consisted of somatically healthy individuals (n=60). The level of the activity of all three types of SOD (Cu/Zn-SOD+MnSOD+Fe-SOD) and the level of AOPPs were analysed in the serum by enzyme immunoassay.Results.All CHF patients as compared to somatically healthy individuals showed an increase in the level of AOPPs and a decrease in the activity of total SOD, being more pronounced in patients with a low left ventricular ejection fraction. In the subgroups of patients with a more severe CHF stage, a statistically significant increase in the level of AOPPs and a decrease in the activity of total SOD as compared with subgroups with a less severe CHF were observed. Patients with a low ejection fraction of the left ventricle of I, IIA and IIB+III stages experienced higher levels of AOPPs and lower levels of total SOD than patients with a preserved left ventricular ejection fraction of the corresponding stages of the disease. A correlation analysis revealed the presence of statistically significant correlations of medium strength in patients with CHF with a preserved and low left ventricular ejection fraction with the clinical manifestations of CHF.Conclusion.The dynamics of the total SOD and AOPP levels, depending on the left ventricular ejection fraction and the stage of the disease, indicates the association of the CHF severity with that of oxidative stress. Conflict of interest: the author declares no conflict of interest.

Afferent Loop Syndrome Masquerading as Recurrent Acute Pancreatitis

Introduction Afferent loop syndrome (ALS) is a rarely described complication following gastric-bypass surgery and the creation of gastro-jejunostomy. We present a case of this disorder mimicking recurrent acute pancreatitis. Case presentation A 67 yr old Caucasian F underwent Roux-en-Y gastric bypass in 2012. Initially had good weight loss and no post-operative complications. In 2017, began to develop recurrent episodes of epigastric/RUQ pain, N/V. CT scan showed cholelithiasis and internal hernia. Labs were all normal, including CBC, hepatic function, and lipase. She underwent cholecystectomy and hernia repair. Patient continued to have pain, but this time with lipase greater than 3 times the upper limit of normal concerning for pancreatitis. MRCP was normal except mildly dilated CBD, however CT showed dilated loops of small bowel in pelvis. Repeat surgical exploration was performed with extensive lysis of adhesions. Patient continued to have intermittent pain with elevation of lipase concerning for pancreatitis. Autoimmune pancreatitis was ruled out. Given dilated CBD and increasing ALP, there was concern for SOD type 1. Lap assisted ERCP was performed which showed papillary stenosis and was treated with dual sphincterotomy. Following ERCP patient did well for about 1 month until similar pain led to repeat hospitalization. Lipase was elevated as well. CT showed significantly dilated duodenum and remnant stomach concerning for afferent loop syndrome. Patient underwent revision of jejunostomy with biliopancreatic limb being re-anastomosed 10cm distal to prior site with 10cm long anastomosis to prevent recurrence. Following this procedure patient had complete resolution of symptoms. Discussion ALS is a consequence of partial or complete obstruction of the gastrojejunostomy along the jejunal portion of the afferent limb. Passage of food and gastric secretions through the gastrojejunostomy and into the efferent loop triggers the release of secretin and cholecystokinin, which in turn stimulate secretion of upto 1-2 L of pancreatic and biliary secretions into the afferent loop each day. Symptoms are usually caused by increased intraluminal pressure and distention due to accumulation of these secretions in an obstructed afferent limb. This can present as obstructive jaundice, ascending cholangitis, and pancreatitis. Our case serves to highlight the importance of taking a multi-disciplinary approach to these complicated patients with ongoing abdominal pain.1384_A.tif Figure 1: No Caption available.1384_B.tif Figure 2: No Caption available.

Qualitative assessment of souls in technogenic landscapes of Gorlovskiy anthracitous deposit

The paper highlights the results of Morphological studies of soils formed on the outer 30year dumps of overburden and host rocks of the Gorlovskiy deposit and leached chernozem soil. The authors found out that soil covering contains initial, organic accumulative and sod types of embryosimes. Comparative morphological characteristics of soils indicates differences between chernozems and technogenic landscape soils. The results show that soil formation increases concentration of pedogenic organic matter in the soils which is almost equal to that in the black soil. The paper represents qualitative assessment of the soils. The authors calculate the index of specific features which reveals significant differences in the contribution to total variation of different soil properties. The article shows that embryosimes formed on loose sediments are the most fertile. It is established that the level of quality value in rocky soils is determined by concentration of physical clay; in the soils formed on loose rocks it is explained by humus concentration.. The ecosystem is not in a meta-stable climax state; it is developing dynamically, being at the stage of forming sod embryosimes. Therefore, the soil and environmental condition of tailings is satisfactory, as the embryosimes have not been formed after 31 years later the initial phase of technogenesis started. Humus accumulating embryosimes are expected to be formed in the soil covering as well as dry steppe souls on technogenic eluvium and neogenic clays.

Assessing the influence of the genetically modified factor on mixture toxicological interactions in Caenorhabditis elegans: Comparison between wild type and a SOD type

How to evaluate the ecological risk of transgenic technology is a focus of scientists because of the safety concerns raised by genetically modified (GM) organisms. Nevertheless, most studies are based on individual chemicals and always analyze the GM organism as a type of toxicant. In this study, we changed the approach and used GM organisms as the test objects with normal chemical exposure. Three types of chemicals (two substituted phenols, 4-chlorophenol and 4-nitrophenol; two ionic liquids, 1-butylpyridinium chloride and 1-butylpyridinium bromide; two pesticides, dichlorvos and glyphosate) were used to construct a six-component mixture system. The lethality to wild-type (N2) and sod-3::GFP (SOD-3) Caenorhabditis elegans was determined when they were exposed to the same mixture system after 12 and 24 h. The results showed that the pEC50 values of all of the single chemicals on SOD-3 were greater than those on N2 at 24 h. The toxicities of the single chemicals and nine mixture rays on the two strains increased with time. Notably, we discovered a significant difference between the two strains; time-dependent synergism occurred in mixtures on N2, but time-dependent antagonism occurred in mixtures on SOD-3. Finally, the strength of the synergism or antagonism turned to additive action on the two strains as the exposure time increased. These findings illustrated that the GM factor of the nematode influenced the mixture toxicological interaction at some exposure times. Compared with N2, SOD-3 were more sensitive to stress or toxic reactions. Therefore, the influence of the GM factor on mixture toxicological interactions in environmental risk assessment must be considered.

ZnO Nanorod-Induced Heteroepitaxial Growth of SOD Type Co-Based Zeolitic Imidazolate Framework Membranes for H2 Separation.

Up to now, the fabrication of well-intergrown Co-based zeolitic imidazolate framework (ZIF) membranes on porous tubular supports is still a major challenge. We report here a heteroepitaxial growth for preparing well-intergrown Co-based ZIFs (ZIF-67 and ZIF-9) tubular membranes with high performance and excellent thermal stability by employing a thin layer of ZnO nanorods acting as both nucleation centers and anchor sites for the growth of metal-organic framework membranes. The results show that well-intergrown Co-ZIF-67 and Co-ZIF-9 membranes are successfully achieved on the ZnO nanorod-modified porous ceramic tubes. This highly active heteroepitaxial growth may be attributed to the fact that the (Zn,Co) hydroxy double salt intermediate produced in situ from ZnO nanorods acts as heteroseeds and enables the uniform growth of Co-based membranes. The H2/CO2 selectivity of the as-prepared Co-ZIF-9 tubular membrane could reach about 23.8 and the H2/CH4 selectivity of Co-ZIF-67 tubular membrane is as high as 45.4. Moreover, the membranes demonstrate excellent stability because of the ZnO nanorods as linkers between the membrane and substrate.

MnTBAP therapy attenuates the downregulation of sodium transporters in obstructive kidney disease.

Ureteral obstruction is associated with reduced expressions of renal sodium transporters, which contributes to impaired urinary concentrating capacity. In this study, we employed a synthetic mitochondrial superoxide dismutase 2 (SOD2) mimic MnTBAP to investigate the role of mitochondrial oxidative stress in modulating the sodium transporters in obstructive kidney disease. Following unilateral ureteral obstruction (UUO) for 7 days, a global reduction of sodium transporters including NHE3, NCC, NKCC2, and ENaCα was observed as determined by qRT-PCR, Western Blotting or immunohistochemistry. Among these sodium transporters, the downregulation of NHE3, NCC, and NKCC2 was partially reversed by MnTBAP treatment. In contrast, the reduction of ENaCα was not affected by MnTBAP. The β and γ subunits of ENaC were not significantly altered by ureteral obstruction or MnTBAP therapy. To further confirm the anti-oxidant effect of MnTBAP, we examined the levels of TBARs in the urine collected from the obstructed ureters of UUO mice and bladder of sham mice. As expected, the increment of urinary TBARs in UUO mice was entirely abolished by MnTBAP therapy, indicating an amelioration of oxidative stress. Meantime, we found that three types of SOD were all reduced in obstructed kidneys determined by qRT-PCR, which was unaffected by MnTBAP. Collectively, these results demonstrated an important role of mitochondrial oxidative stress in mediating the downregulation of sodium transporters in obstructive kidney disease.

Assessment of Changes in Sod Under Intensive Use

AbstractThe paper presents research results which aimed at evaluation of the change in the sodding degree and selected strength parameters of sod used with varied intensity; additionally sod was modified through administration of biopreparation. Measurements were taken on two types of sod. The first one was formed from perennial rye grass, the second one from orchard grass. It was proved that the use of the investigated facilities resulted in reduction of sodding, which was related to the sod forming species. No impact of biopreparation use on the sodding degree was proved. Intensive use affected the increase of the value of the analysed strength parameters; at low soil moisture (5.0-5.5%) considerable compaction in the surface layer of soil was reported.

A Single Outer-Sphere Mutation Stabilizes apo-Mn Superoxide Dismutase by 35 °C and Disfavors Mn Binding.

The catalytic active site of Mn-specific superoxide dismutase (MnSOD) is organized around a redox-active Mn ion. The most highly conserved difference between MnSODs and the homologous FeSODs is the origin of a Gln in the second coordination sphere. In MnSODs it derives from the C-terminal domain whereas in FeSODs it derives from the N-terminal domain, yet its side chain occupies almost superimposable positions in the active sites of these two types of SODs. Mutation of this Gln69 to Glu in Escherichia coli FeSOD increased the Fe3+/2+ reduction midpoint potential by >0.6 V without disrupting the structure or Fe binding [ Yikilmaz, E., Rodgers, D. W., and Miller, A.-F. ( 2006 ) Biochemistry 45 ( 4 ), 1151 - 1161 ]. We now describe the analogous Q146E mutant of MnSOD, explaining its low Mn content in terms increased stability of the apo-Mn protein. In 0.8 M guanidinium HCl, Q146E-apoMnSOD displays an apparent melting midpoint temperature (Tm) 35 °C higher that of wild-type (WT) apoMnSOD, whereas the Tm of WT-holoMnSOD is only 20 °C higher than that of WT-apoMnSOD. In contrast, the Tm attributed to Q146E-holoMnSOD is 40 °C lower than that of Q146E-apoMnSOD. Thus, our data refute the notion that the WT residues optimize the structural stability of the protein and instead are consistent with conservation on the basis of enzyme function and therefore ability to bind metal ion. We propose that the WT-MnSOD protein conserves a destabilizing amino acid at position 146 as part of a strategy to favor metal ion binding.

The effect of moisture content on fraction recovery and the development of a rapid field test for moisture determination of sod peat (sod moss and bin sods)

Peat fractions can be produced either by milling peat in the bog, or producing sod peat and breaking these sods into the desired fractions. Two types of sods exist: bin sods, and sod moss. Bin sods are produced by extrusion of peat, from more decomposed peat (H6-H7), and sod moss are sods cut directly from the bog, where less decomposed peat is used (H5-H6). Both sods are dried on the bog before being used the horticultural industry. The fractions produced from sods are more uniform compared to those from milled peat and they are reported to be more mechanically stable than fractions from milled peat However, experience has shown that considerable variation in fraction recovery can exist during the production of fractions from sods. In some cases, clean fractions are produced with very little fine particles, and in other cases, high volumes of fine particles are produced. There is some evidence to show that moisture content has a considerable bearing on the fraction recovery from sods. However, there is little or no information available other than anecdotal, on the effect of moisture content on the amount of fines generation during sod breakdown when forming fractions. In this study, the effect of moisture content of fractions from both sod moss and bin sods on fines generation were studied, under laboratory conditions. Moisture content was measured on the screened fractions. Sods were dried to various moisture levels (sod moss 30-80% and bin sods from 25 to 85% moisture content from two bogs). Resultant peat fractions from sod moss and bin sods (10-20 mm) were placed into a container with golf balls, and agitated in a cement mixer to simulate mechanical breakdown conditions. The fines generated were then determined by particle size determination using standard methods. There was a very strong correlation between fines generation and fraction moisture content in sods (r2=0.82 for sod moss and r2=0.80 for bin sods). An upper limit for moisture content of sod moss (54% v/v) and bin sods (62%) was then determined using the Cate-Nelson technique, that is the moisture content at which, when exceeded, high volumes of fines is generated. Subsequently, an accurate field test was developed for moisture determination. This cheap, quick and robust method ensures that only sods of the correct moisture content are used for fraction generation.

Cloning and characterization of iron-superoxide dismutase in Antarctic yeast strain Rhodotorula mucilaginosa AN5.

A novel superoxide dismutase gene from Antarctic yeast Rhodotorula mucilaginosa AN5 was cloned, sequenced, and then expressed in Escherichia coli. The R. mucilaginosa AN5 SOD (RmFeSOD) gene was 639 bp open reading frame in length, which encoded a protein of 212 amino acids with a deduced molecular mass of 23.5 kDa and a pI of 7.89. RmFeSOD was identified as iron SOD type with a natural status of homodimer. The recombinant RmFeSOD showed good pH stability in the pH 1.0-9.0 after 1 h incubation. Meanwhile, it was found to behave relatively high thermostability, and maintained more than 80% activity at 50 °C for 1 h. By addition of 1 mM metal ions, the enzyme activity increased by Zn2+ , Cu2+ , Mn2+ , and Fe3+ , and inhibited only by Mg2+ . RmFeSOD showed relatively low tolerance to some compounds, such as PMSF, SDS, Tween-80, Triton X-100, DMSO, β-ME, and urea. However, DTT showed no inhibition to enzyme activity. Using copper stress experiment, the RmFeSOD recombinant E. coli exhibited better growth than non-recombinant bacteria, which revealed that RmFeSOD might play an important role in the adaptability of heavy metals.

Superoxide dismutase genes in Pyropia haitanensis: molecular cloning, characterization and mRNA expression

Superoxide dismutase (SOD, EC 1.15.1.1) is the first and most important line of cellular defense against oxidative stress. In this study, based on unigene sequences of P. haitanensis, three full-length PhSOD genes were obtained by RACE technology, and named PhMSD, PhCSD1 and PhCSD2. The full-length cDNAs of these genes comprised 973, 1 029 and 954 nucleotides, respectively. The cDNAs encoded proteins of 224, 134 and 216 amino acids, with isoelectric points of 5.75, 4.65 and 10.74, respectively. Based on their conserved motifs and phylogenetic tree analysis, the three PhSODs were divided into two SOD types: PhMSD is a Mn-SOD, and PhCSD1 and PhCSD2 are CuZn-SODs. qPCR was used to measure the expression of the three PhSOD genes in different life phases of P. haitanensis, and under different periods of high-temperature stress and different levels of desiccation. In the different life phases of P. haitanensis, the expression levels of the three PhSODs were all significantly higher in the thallus than in the conchocelis. During high-temperature and desiccation stress, the expression levels of PhCSD1 and PhCSD2 were highly induced by the O2- content, but the expression level of PhMSD was highly depressed by high temperature stress and showed no significant change during desiccation.

A Trial of Rectal Indomethacin to Prevent Post-ERCP Pancreatitis in Patients with Suspected Type 3 Sphincter of Oddi Dysfunction.

Recent data have suggested that rectal indomethacin can also reduce the incidence of post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP). The aim of this study was to determine whether prophylactic rectal indomethacin with PD stenting would reduce the incidence and severity of PEP compared to PD stenting alone in patients undergoing manometry for suspected SOD type 3. A retrospective review of consecutive patients who underwent an ERCP with manometry for suspected SOD type 3 was performed. Patients were divided into two groups: (a) those who received a prophylactic PD stent (n=285) and (b) those who received a prophylactic PD stent and a single dose of 100-mg indomethacin suppositories after ERCP (n=57). The rate of PEP was compared between the two groups. The two patient groups were similar with regard to patient and procedure risk factors for PEP. Post-ERCP pancreatitis developed in 22% patients. There was no significant difference in the incidence of PEP in the PD stent group compared to the PD stent and indomethacin group (23 vs. 18%, respectively; p=0.39). Moderate-to-severe pancreatitis developed in 21 (7%) patients in the PD stent group compared to 5 (9%) patients in the PD stent and indomethacin group (p=0.78). Among patients with PEP, the median length of hospital stay was not significantly longer in the PD stent group compared to the PD stent and indomethacin group (6 vs. 4days, respectively; p=0.11). In patients with suspected SOD type 3, prophylactic rectally administered indomethacin with PD stenting was not observed to affect the incidence or severity of post-ERCP pancreatitis when compared to PD stenting alone.

Ionothermal syntheses of transition-metal-substituted aluminophosphate molecular sieves in the presence of tetraalkylammonium hydroxides

Transition-metal-substituted aluminophosphate (MeAPO) molecular sieves with SOD and AEI framework types have been synthesized ionothermally in the ionic liquid 1-ethyl-3-methylimidazolium bromide with adding four tetraalkylammonium hydroxides, including tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide. Detailed synthetic investigation shows that the nature and concentration of the tetraalkylammonium hydroxide, the Me/Al ratio in the reaction mixture and the metal sources greatly influence the phase selectivity of the reaction. The products have been characterized by PXRD, SEM, ICP, CHN, UV–Vis spectroscopy, 13C, 27Al and 31P MAS NMR, and TG. The results reveal that the tetraalkylammonium cations compete with the ionic liquid cations to act as the structure directing agent. The templating ability of the tetraalkylammonium cations and the ionic liquid cations is closely related to their charge densities.

Metatranscriptome profiling reveals versatile N-nutrient utilization, CO2 limitation, oxidative stress, and active toxin production in an Alexandrium fundyense bloom

The globally increasing trend of harmful algal blooms (HAB) is often attributed to coastal eutrophication and climate change, but the physiological processes at play during a bloom are poorly understood due to lack of in situ measurements of these processes or their corresponding molecular machinery. Here we employed a dinoflagellate spliced leader-based 454-pyrosequencing technique to generate time-serial expressed sequence tags (EST) throughout a diel cycle during an Alexandrium fundyense bloom in Long Island Sound. Assembly of the reads yielded 87,273 dinoflagellate genes. To facilitate mapping of these data to species and comparing of gene expression dynamics between natural bloom and laboratory culture conditions, similar diel EST sets were sequenced for A. fundyense strain CCMP1719, which achieved 31,451 genes. The assembled metatranscriptome reveals a metabolically active A. fundyense population. Relative to the laboratory culture, the natural bloom expressed more abundantly genes related to nitrogen (N)-scavenging, CO2-concentrating and saxitoxin production. Most strikingly, the data showed a versatility to exploit various sources of N (cyanate, urea, nitrate/nitrite, and ammonium), likely conferring competitive advantages in A. fundyense for bloom formation or maintenance. The dataset also led to the first characterization of Ni-containing superoxide dismutases (NiSODs) in dinoflagellates with mitochondrial targeting signal identified, which along with other types of SOD found indicated diverse SODs being expressed in the A. fundyense bloom. Our results also demonstrate that metatranscriptomics is an effective approach to unraveling physiological processes conducive to HAB outbreaks.