Catalytic Activities Of [GADV]-Peptides

We have previously postulated a novel hypothesis for the origin of life, assuming that life on the earth originated from “[GADV]-protein world”, not from the “RNA world” (see Ikehara's review, 2002). The [GADV]-protein world is constituted from peptides and proteins with random sequences of four amino acids (glycine [G], alanine [A], aspartic acid [D] and valine [V]), which accumulated by pseudo-replication of the [GADV]-proteins. To obtain evidence for the hypothesis, we produced [GADV]-peptides by repeated heat-drying of the amino acids for 30 cycles ([GADV]-P₃₀) and examined whether the peptides have some catalytic activities or not. From the results, it was found that the [GADV]-P₃₀ can hydrolyze several kinds of chemical bonds in molecules, such as umbelliferyl-β-D-galactoside, glycine-p-nitroanilide and bovine serum albumin. This suggests that [GADV]-P₃₀ could play an important role in the accumulation of [GADV]-proteins through pseudo-replication, leading to the emergence of life. We further show that [GADV]-octapaptides with random sequences, but containing no cyclic compounds as diketepiperazines, have catalytic activity, hydrolyzing peptide bonds in a natural protein, bovine serum albumin. The catalytic activity of the octapeptides was much higher than the [GADV]-P₃₀ produced through repeated heat-drying treatments. These results also support the [GADV]-protein-world hypothesis of the origin of life (see Ikehara's review, 2002). Possible steps for the emergence of life on the primitive earth are presented.     

Continuous removal of Cr(VI) from aqueous solution catalysed by palladised biomass of Desulfovibrio vulgaris

Growth-decoupled cells of Desulfovibrio vulgaris NCIMB 8303 can be used to reduce Pd(II) to cell-bound Pd(0) (Bio-Pd⁰), a bioinorganic catalyst capable of reducing hexavalent chromium to less toxic Cr(III), using formate as the electron donor. Magnetic resonance imaging showed that Bio-Pd⁰, immobilized in chitosan and agar beads, is distinguishable from the surrounding gel and is evenly dispersed within the immobilization matrix. Agar-immobilized Bio-Pd⁰ and `chemical Pd⁰' were packed into continuous-flow reactors, and challenged with a solution containing 100 m Cr(VI) (pH 7) at a flow rate of 2.4 ml h^–1. Agar-immobilized chemical Pd⁰ columns lost Cr(VI) reducing ability by 160 h, whereas columns containing immobilized Bio-Pd⁰ maintained 90% reduction until 680 h, after which reduction efficiency was gradually lost.     

Translocation of 15N indicates nitrogen recycling in the mat-forming lichen Cladonia portentosa

Nitrogen translocation was measured in Cladonia portentosa during 2 yr growth in Scottish heathland. Translocation was predicted to occur if N is resorbed from senescent basal tissue and recycled within the thallus. (15)N was introduced into either the lower (TU thalli) or upper (TD thalli) 25 mm of 50-mm-long thalli as (15)N-NH(4) (+), (15)N-NO(3) (-) or (15)N-glycine. Labelled thalli were placed within intact lichen cushions, either upright (TU) or inverted (TD). Vertical distribution of label was quantified immediately following labelling and after 1 and 2 yr. Independently of the form of introduced label, (15)N migrated upwards in TU thalli, with new growth being a strong sink. Sink regions for (15)N during year 1 (including new growth) became sources of (15)N translocated to new growth in year 2. Upward migration into inverted bases was minimal in TD thalli, but was again marked in new growth that developed from inverted apices. Relocation of N to regions of growth could facilitate internal N recycling, a process postulated to explain the ecological success of mat-forming lichens.     

beta-cyclodextrin-immobilized (4S)-phenoxy-(S)-proline as a catalyst for direct asymmetric aldol reactions

beta-Cyclodextrin-immobilized (4S)-phenoxy-(S)-proline was prepared conveniently by simply heating the amino acid and beta-cyclodextrin in ethanol-water (1/1, v/v) and removal of the solvent. This proved to be an efficient catalyst for direct asymmetric aldol reactions, and the catalyst could be recycled four times without loss of enantioselectivity.     

Zinc Casting and Recycling (8 pp)

Aim, Scope and Background Metal die casting is a highly energy-intensive industry. In addition to that, the production of primary zinc by smelting consumes huge amounts of energy as well as generates many types of pollution. This paper uses LCA to investigate the environmental performance of a zinc cast product. The areas of environmental concern are focused on the direct and indirect air emissions that arise from the Zinc Smelting, Casting and Recycling, as well as transportation. Main Features The LCA case study employs a cradle-to-gate approach, which starts with the purchasing of primary zinc from abroad, casting, inspection, and ends when the scrap metal is sent back for recycling by truck. Based on a “generic” zinc casting product, the objective of the LCA was to compare the air emissions from the material cycle due to: i) the increased content of recycled metal in the final cast product; and ii) the choice of selecting between two Remelters (A and B), the first located near the company and the other in a neighbouring country, to send zinc scrap for recycling. The LCA SimaPro software (version 5.0) Eco-indicator “99 method is used to perform an impact assessment for Climate Change, Acidification, Ecotoxicity, Respiratory Inorganics, and Respiratory Organics was performed. Results The results from direct (process) and indirect (power plants) air emissions confirmed that the major air pollution occurs during Zinc Smelting, that is up to approximately 65–70%. Although an increase in recycling rates resulted in higher levels of air pollution from transportation as well as heavy metals from dross, these two issues were insignificant compared to the huge amount of energy consumed for primary metal production. Based on air pollution from transportation alone, a significant reduction of greenhouse gases and VOCs of 90% each was appreciated when Remelter A was selected. Conclusion The results verified that efforts to recycle zinc and consume the material in a more sustainable manner have become highly important. Also, a second LCA investigation that was made to compare zinc cast products that consists of: 100% primary zinc, mixtures of 50–50% and 40–60% primary-to-recycled zinc, and finally 100% recycled zinc; further emphasized the need for using recycled metal, as opposed to using primary metal.     

The Effect of Fish Introductions on the Diatom and Cladoceran Communities of Lake Opeongo,Ontario, Canada

Fish introductions are one of the most widespread anthropogenic perturbations to aquatic ecosystems. Paradoxically, the effects of these introductions on aquatic ecosystems are typically poorly documented. This project studied the effect of fish introductions on Lake Opeongo, an oligotrophic lake in Algonquin Provincial Park, Ontario, Canada (45° 42′ N, 78° 22′ W), using the remains of algae (diatoms) and zooplankton (cladocerans) preserved in the sediments. It was hypothesized that the introduction of cisco or lake herring (Coregonus artedii Lesueur) in 1948, which filled the underutilized pelagic forage fish niche, should have altered nutrient availability for phytoplankton. Prior to cisco introduction, the diatom community of Lake Opeongo reflected a relatively stable oligotrophic state established before European settlement, and consisted of the Cyclotella stelligera complex with subdominants Tabellaria flocculosa IIIp and the Aulacoseira distans complex. No marked changes occurred until ca. 1962 when the diatom community shifted to an assemblage with increased total phosphorus preferences, consisting of Asterionella formosa and lesser amounts of Cyclotella bodanica var lemanica, the C. stelligera complex, Fragilaria crotonensis and T. flocculosa IIIp. The dominant cladoceran Bosmina longirostris increased significantly in relative abundance since the introduction of cisco. The most likely cause of this shift was increased nutrient recycling and/or trophic level changes caused by human manipulation of the fish community of the lake.     

Utilization and management of organic wastes in Chinese agriculture: Past, present and perspectives

Recycling and composting of organic materials such as animal waste, crop residues and green manures has a long tradition in China. In the past, the application of organic manures guaranteed a high return of organic materials and plant mineral nutrients and thus maintained soil fertility and crop yield. As a result of rapid economic development coupled with the increasing urbanization and labour costs, the recycling rate of organic materials in Chinese agriculture has dramatically declined during the last two decades, in particular in the more developed eastern and southeastern provinces of China. Improper handling and storage of the organic wastes is causing severe air and water pollution. Because farmers are using increasing amounts of mineral fertilizer, only 47% of the cropland is still receiving organic manure, which accounted for 18% of N, 28% of P and 75% of K in the total nutrient input in 2000. Nowadays, the average proportion of nutrients (N+P+K) supplemented by organic manure in Chinese cropland is only 35% of the total amount of nutrients from both inorganic and organic sources. In China, one of the major causes is the increasing de-coupling of animal and plant production. This is occurring at a time when "re-coupling" is partly being considered in Western countries as a means to improve soil fertility and reduce pollution from animal husbandry. Re-coupling of modern animal and plant production is urgently needed in China. A comprehensive plan to develop intensive animal husbandry while taking into account the environmental impact of liquid and gaseous emissions and the nutrient requirements of the crops as well as the organic carbon requirements of the soil are absolutely necessary. As a consequence of a stronger consideration of ecological aspects in agriculture, a range of environmental standards has been issued and various legal initiatives are being taken in China. Their enforcement should be strictly monitored.     

Characterization of a whole‐cell catalyst co‐expressing glycerol dehydrogenase and glucose dehydrogenase and its application in the synthesis of L‐glyceraldehyde

A whole‐cell catalyst using Escherichia coli BL21(DE3) as a host, co‐expressing glycerol dehydrogenase (GlyDH) from Gluconobacter oxydans and glucose dehydrogenase (GDH) from Bacillus subtilis for cofactor regeneration, has been successfully constructed and used for the reduction of aliphatic aldehydes, such as hexanal or glyceraldehyde to the corresponding alcohols. This catalyst was characterized in terms of growth conditions, temperature and pH dependency, and regarding the influence of external cofactor and permeabilization. In the case of external cofactor addition we found a 4.6‐fold increase in reaction rate caused by the addition of 1 mM NADP⁺. Due to the fact that pH and temperature are also factors which may affect the reaction rate, their effect on the whole‐cell catalyst was studied as well. Comparative studies between the whole‐cell catalyst and the cell‐free system were investigated. Furthermore, the successful application of the whole‐cell catalyst in repetitive batch conversions could be demonstrated in the present study. Since the GlyDH was recently characterized and successfully applied in the kinetic resolution of racemic glyceraldehyde, we were now able to transfer and establish the process to a whole‐cell system, which facilitated the access to L ‐glyceraldehyde in high enantioselectivity at 54% conversion. All in all, the whole‐cell catalyst shows several advantages over the cell‐free system like a higher thermal, a similar operational stability and the ability to recycle the catalyst without any loss‐of‐activity. The results obtained making the described whole‐cell catalyst an improved catalyst for a more efficient production of enantiopure L ‐glyceraldehyde. Biotechnol. Bioeng. 2010;106: 541–552. © 2010 Wiley Periodicals, Inc.     

On the biogenesis of myelin membranes: Sorting, trafficking and cell polarity

In the central nervous system, a multilayered membrane layer known as the myelin sheath enwraps axons, and is required for optimal saltatory signal conductance. The sheath develops from membrane processes that extend from the plasma membrane of oligodendrocytes and displays a unique lipid and protein composition. Myelin biogenesis is carefully regulated, and multiple transport pathways involving a variety of endosomal compartments are involved. Here we briefly summarize how the major myelin proteins proteolipid protein and myelin basic protein reach the sheath, and highlight potential mechanisms involved, including the role of myelin specific lipids and cell polarity related transport pathways.     

Uric acid recycling in the shield bug, Parastrachia japonensis (Hemiptera: Parastrachiidae), during diapause

Nymphs of the univoltine shield bug, Parastrachia japonensis grow by feeding on the drupes of their sole food plant, which are available for only 2 weeks a year. The new adults soon enter a reproductive diapause and survive without feeding for at least 10 months up to 2 years. Uric acid was found to be the predominant component among four waste nitrogenous compounds, i.e., uric acid, allantoin, allantoic acid and urea in the body of both nymphs and adults in all stages, and to be predominantly excreted by the nymphs and reproductive adults. However, adults in diapause excreted negligible amounts of these compounds. Erwinia-like bacteria were found exclusively in the cecum of midgut, in which three uricolytic enzymes, i.e., uricase, allantoinase and allantoicase were detected. Ninety % of adults in diapause could survive on water for 9 months, but those given 0.02% rifampicin aqueous solution all died within this period, with significant reduction of the bacteria and uricase activity in the cecum. Rifampicin treatment resulted in a considerable reduction of free amino acids, especially proline in the hemolymph. These results suggest that uric acid is recycled as an amino acid source with the aid of Erwinia-like bacteria, and uricase functions as a key enzyme for this process.