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Operating fluid catalytic cracking (FCC) units with feedstocks high in iron was reported to cause degradation in performance. However, nearly all prior work examining this phenomenon used incorporated FCC catalysts. An alternative production method involves synthesizing the catalyst in situ, which may circumvent the performance degradation observed previously. An opportunity to assess this question was provided by a refinery that simultaneously operated an in situ and an incorporated FCC catalyst. Under severe iron contamination, the incorporated catalyst showed lower bottoms upgrading and higher dry gas, both hallmarks of iron poisoning; whereas the in situ catalyst appears relatively unaffected.

Iron, as an essential element for plants and microorganisms, plays a significant role in photosynthesis, photopigment synthesis, nitrogen fixation, nucleic acid synthesis, etc. However, in iron rich environments, it causes stress by affecting various physiological activities including ROS generation and detoxification machineries. Here, we investigated the protective role of antioxidative enzymes and antioxidants against iron-induced oxidative stress in the cyanobacteria, Anabaena sphaerica from the iron rich regions of Chhattisgarh. We evaluated various morpho-physiological modifications at different concentrations of iron (0, 20, 50, 75 and 100 µM FeCl3). Microscopic and physiological characterization showed highest order of structural deformities, reactive oxygen species (ROS) generation and lipid peroxidation at 100 µM FeCl3 but growth was reduced only by 28%. Possibly, maximum superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities along with highest level of antioxidants (carotenoid, proline, cysteine and non protein thiol) played a major role in protecting the growth. As compared to 20 µM FeCl3 treated cells of A. sphaerica, almost equal growth and no structural alterations at 50 and 75 µM FeCl3 may be correlated with minimum ROS, electrolyte leakage and malondialdehyde (MDA) content along with an activation of efficient ROS detoxification machinery i.e. enhanced level of antioxidative enzymes and antioxidants. Thus, the inherited property of A. sphaerica to grow at iron enriched condition make it more efficient microbe for improvement of the nitrogen status in the soil. [ABSTRACT FROM AUTHOR]

Iron and zinc are two trace elements that are essential for rice. But they are toxic at higher concentrations, leading to severe rice yield losses especially in acid soils and inland valleys. In this study, two reciprocal introgression line (IL) populations sharing the same parents were used with high-density SNP bin markers to identify QTL tolerant to iron and zinc toxicities. The results indicated that the japonica variety 02,428 had stronger tolerance to iron and zinc toxicities than the indica variety Minghui 63. Nine and ten QTL contributing to iron and zinc toxicity tolerances, respectively, were identified in the two IL populations. The favorable alleles of most QTL came from 02,428. Among them, qFRRDW2, qZRRDW3, and qFRSDW11 appeared to be independent of genetic background. The region C11S49–C11S60 on chromosome 11 harbored QTL affecting multiple iron and zinc toxicity tolerance-related traits, indicating partial genetic overlap between the two toxicity tolerances. Our results provide essential information and materials for developing excellent rice cultivars with iron and/or zinc tolerance by marker-assisted selection (MAS).

Iron toxicity is a major nutrient disorder that severely affects crop development and yield. Vacuolar detoxification of metal stress is an important strategy for plants to survive and adapt to this adverse environment. Vacuolar iron transporter (VIT) members are involved in this process and play essential roles in iron storage and transport. In this study, a rapeseed VIT gene BnMEB2 (BnaC07g30170D) was identified. BnMEB2 is a homolog to Arabidopsis MEB2 (At5g24290) and acts as a detoxifier in vacuolar sequestration of divalent metal. Transient expression analysis revealed that BnMEB2 was localized to the vacuolar membrane. Q-PCR detection showed a high expression of BnMEB2 in mature (60-day-old) leaves and could be obviously induced by exogenous iron stress in both roots and leaves. Over-expressed BnMEB2 in both Arabidopsis wild type and meb2 mutant seedlings resulted in greatly improved iron tolerability with no significant changes in the expression level of other vacuolar iron transporter genes. The mutant meb2 grew slowly and its root hair elongation was inhibited under high iron concentration condition while BnMEB2 over-expressed transgenic plants of the mutant restored the phenotypes with apparently higher iron storage in roots and dramatically increased iron content in the whole plant. Taken together, these results suggested that BnMEB2 was a VIT gene in rapeseed which was necessary for safe storage and vacuole detoxification function of excess iron to enhance the tolerance of iron toxicity. This research sheds light on a potentially new strategy for attenuating hazardous metal stress from environment and improving iron biofortification in Brassicaceae crops.

Desde o século quinze que é tradicionalmente cultivado trigo na Ilha da Madeira. Em sequeiro, sob condições microclimáticas diversificadas, em terraços isolados e dispostos em encostas íngremes, o trigo ocupa solos ácidos, sobretudo da classe dos Andossolos, com elevada concentração de ferro. Nestes solos, os óxidos de ferro constituem o principal agente inorgânico de ligação das partículas do solo, contribuindo para a estabilidade dos agregados. Foi realizada uma experiência com sessenta cultivares tradicionais de trigo (landraces de Triticum spp.) do Banco de Germoplasma, da Universidade da Madeira, em soluções nutritivas com 10 (controlo) ou 600 mM Fe, durante 5 dias, após 2 dias de crescimento inicial das plântulas. O alongamento da principal raiz primária foi medido para cada planta sob stress e calculada a média do incremento relativo ao controlo (como percentagem de Incremento Radicular Relativo ou IRR; n = 28). O IRR evidenciou ser um indicador sensível da toxicidade do ferro em trigo. Mais de 85% do germoplasma estudado evidenciou IRR superior a 50%, enquanto o IRR correspondente a sete landraces ultrapassou o valor de 70%. Isto foi considerado como indicador da maior tolerância ao excesso de ferro destas landraces de trigo, as quais poderão ter especial interesse na ocupação de solos ricos em compostos inorgânicos de ferro, nas zonas tropicais e subtropicais.Since the fifteen century, the rainfed-cultivation of wheat for grain is traditionally performed on the Island of Madeira. Under several microclimatic conditions and along very sloppy mountains, the landraces are grown on isolated terraces of Andosols with high amounts of iron. Iron oxides are the main inorganic binding agent contributing to the stability of aggregates and to soil fertility in long-term sustainable agriculture in acid and iron-rich soils. After a two day period of seedling initial growth, a screening test of sixty traditional wheat (Triticum spp.) landraces from the ISOPlexis Genebank at the University of Madeira, Funchal, was performed using nutrient solutions containing 10 or 600 mM Fe, during five days, under controlled laboratory conditions. The elongation of the longest primary root was measured for each genotype and the mean root increment relative to control (as, % relative root increment or RRI; n=28) calculated. This parameter appeared to be a sensitive indicator of Fe tolerance in wheat. Over 85% of wheat germplasm showed the RRI higher than 50%, while the RRI of seven accessions exceeded 70%. This indicates that those landraces are Fe tolerant and might be of particular interest for cultivation under acid rich iron soils of tropical and subtropical areas.

Operating fluid catalytic cracking (FCC) units with feedstocks high in iron was reported to cause degradation in performance. However, nearly all prior work examining this phenomenon used incorporated FCC catalysts. An alternative production method involves synthesizing the catalyst in situ , which may circumvent the performance degradation observed previously. An opportunity to assess this question was provided by a refinery that simultaneously operated an in situ and an incorporated FCC catalyst. Under severe iron contamination, the incorporated catalyst showed lower bottoms upgrading and higher dry gas, both hallmarks of iron poisoning; whereas the in situ catalyst appears relatively unaffected. [Display omitted] • Synthesis route is critical in defining the tolerance of FCC catalysts to iron. • FCC catalysts from in situ synthesis are inherently more resistant to iron poisoning. • Open pore architecture is crucial for performance of FCC catalysts with high contaminant iron. • Absence of metakaolin can lower susceptibility of FCC catalysts to iron poisoning. • Conversion of metakaolin during in situ synthesis can help iron tolerance. [ABSTRACT FROM AUTHOR]

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Abstract: Studies directed at cyanobacteria inhabiting iron-depositing hot springs may provide insights into the role of both ancient and contemporary cyanobacteria mediated iron transformations. Here we phylogenetically, morphologically and physiologically characterize a novel cyanobacterium isolated from an iron-depositing hot spring. Phylogenetic analyses indicate that the bacterium is a representative of a new genus, exhibiting a maximum 95.2% homology to database sequences. The isolate is a unicellular cyanobacterium with bladder-like cells typically packed as duplexes, or in extracellular polymeric substance covered clumps and small chains without the ability to produce baeocystes. No growth without added combined nitrogen occurred. While requiring relatively large amounts of iron for growth (>40μM), the isolate was shown to facilitate removal of iron from culture media. These results suggest that the isolate may be an important component of an iron-depositing microbial community. The name “Chroogloeocystis siderophila” for this cyanobacterium is proposed. [Copyright &y& Elsevier]

Bacteria mediated synthesis of magnetic nanoparticles (MNPs) for biotechnological applications is an important area of nanotechnology. This study demonstrates the use of iron tolerant bacterium for synthesis of MNPs for cellulase immobilization and photocatalytic activity. The enrichment, isolation, screening and molecular identification led to the selection of Pseudomonas stutzeri KDP_M2 with high degree of iron tolerance. The synthesis parameters such as 1 mM ferric quinate, pH 9 and 96 h static incubation were found optimum for maximum yield of 210 mg/L. The characterization using various techniques indicated that MNPs were Hematite (Fe 2 O 3) with particle size between 10 and 20 nm. Further, vibrating sample magnetometer and thermogravimetric analyses demonstrated the superparamagnetic nature with high thermal stability. The MNPs were found an excellent support for immobilization of industrially important cellulase with 96.5% binding efficiency. The immobilization which was confirmed by Fourier transform infrared spectroscopy indicated that immobilization did not reduce the cellulase activity, rather enhanced the thermal stability and operational temperature range of cellulase. The immobilized cellulase showed maximum cellulolytic activity at pH 4.6 and retained 80% activity upto 3rd cycle of reuse, therefore, can be utilized repeatedly at acidic conditions.The monitoring the photocatalytic activity showed rapid degradation of methyl violet and methylene blue within initial 10 min. of reaction. Unlabelled Image • Iron tolerant P. stutzeri was isolated & identified from industrial disposal site. • P. stutzeri synthesized thermally stable, iron oxide magnetic nanoparticles. • 1 mM ferric quinate, pH 9 & 96 h incubation were optimum synthesis conditions. • Cellulase was immobilized on magnetic nanoparticles with 96.5% binding efficiency. • Magnetic nanoparticles exhibited good photocatalytic activity for dye degradation. [ABSTRACT FROM AUTHOR]

Iron toxicity is a nutrient disorder that severely affects crop development and yield in some soil conditions. Vacuolar detoxification of metal stress is an important strategy for plants to survive and adapt to this adverse environment. Vacuolar iron transporter (VIT) members are involved in this process and play essential roles in iron storage and transport. In this study, we identified a rapeseed VIT gene BnMEB2 (BnaC07g30170D) homologs to Arabidopsis MEB2 (At5g24290). Transient expression analysis revealed that BnMEB2 was localized to the vacuolar membrane. Q-PCR detection showed a high expression of BnMEB2 in mature (60-day-old) leaves and could be obviously induced by exogenous iron stress in both roots and leaves. Over-expressed BnMEB2 in both Arabidopsis wild type and meb2 mutant seedlings resulted in greatly improved iron tolerability with no significant changes in the expression level of other VIT genes. The mutant meb2 grew slowly and its root hair elongation was inhibited under high iron concentration condition while BnMEB2 over-expressed transgenic plants of the mutant restored the phenotypes with apparently higher iron storage in roots and dramatically increased iron content in the whole plant. Taken together, these results suggested that BnMEB2 was a VIT gene in rapeseed which was necessary for safe storage and vacuole detoxification function of excess iron to enhance the tolerance of iron toxicity. This research sheds light on a potentially new strategy for attenuating hazardous metal stress from environment and improving iron biofortification in Brassicaceae crops.