Organic acid production from CO2/H2 and CO/H2 by mixed-culture anaerobes

The gases CO, CO₂, and H₂ were used as substrates in anaerobic fermentations producing organic acids. Various mixed bacterial sources were used, including sewage sludge digester effluent, rabbit feces, and soil. Nonsterile microorganism selection was carried out using CO₂/H₂ and CO/H₂ as the primary carbon and energy sources. Cultures were grown in specially designed, high-pressure (to 70 psig) flasks. Methanogenic bacteria were eliminated from the cultures. Liquid products of the fermentations were acetic through caproic acids, with the even-numbered acids predominating. Carbon balances showed conclusively that acetic acid was formed from carbon contained in the CO or CO₂ feed gas. Measurements made included rates of acid product formation, cell density, and degree of gas utilization. Limited characterization of the microorganisms was also performed. Production of organic acids by mixed culture inocula from CO₂/H₂ or CO/H₂ had not been reported previously. Application of this work is to the production of organic chemicals from synthesis gas (SNG), produced by the gasification of fossil fuels (peat, lignite, and various ranks of coals), biomass (agricultural and forest residues, and various biomass crops grown expressly for energy recovery), and municipal solid waste.     

Estrogen-dependent trypsin-like activity in the rat uterus. Localization of activity in the 12,000g pellet and nucleus.

Direct evidence was obtained for the presence of hormone-stimulated trypsin-like protease activity in the rat uterus. Ovariectomized rats were either untreated (U), treated with estradiol (E), or estradiol plus progesterone (EP). The uteri were excised and subcellular fractions were prepared. Each fraction was assayed for protease activity using protamine as substrate, the cleavage products being quantitated fluorometrically following reaction with 4-phenylspiro[furan-2(3H),1′-phthalan]-3,3′dione (Fluram). Fractions from U rats yielded negative results, whereas the 12,000g pellets and nuclei from the uteri of E and EP rats exhibited appreciable activities. No significant increase in protease activity was observed in thymus and diaphragm following hormone treatment, indicating organ specificity. The enzyme (or enzymes) from the 12,000g pellet was solubilized and some characteristics were determined. The apparent K_m is about 1.0 × 10^?6m, the temperature optimum is about 44 °C and maximum velocity is achieved in the alkaline range (pH ~ 8.5). The protease is a plasminogen activator and is inhibited by diisopropyl fluorophosphate, Antipain, and Leupeptin. These properties resemble those of trypsin.     

Fluorine nuclear magnetic resonance studies of trifluoroacetylinsulin derivatives. Effects of salts and denaturants.

19F nuclear magnetic resonance spectroscopy has been used to study the effects of salts and denaturants on the structure and aggregation properties of several trifluoroacetyl derivatives of insulin. This technique has been shown to be a powerful tool in the study of specific sites on the protein molecule. Circular dichroic and sedimentation velocity studies were also carried out to aid in the interpretation of the magnetic resonance data. At pH 6.8 Zn2+ had no effect on the 19F magnetic resonance spectrum, however, citrate and acetate ions significantly sharpened the signal from the trifluoroacetyl probe at the N-terminal end (glycine A-1) of the insulin A chain. No alterations were observed in the S20,W value of circular dichroic spectra, suggesting that the probe had gained a considerable degree of motional freedom without changes in aggregation or conformational properties. In the absence of perturbants the trifluoroacetyl group on glycine A-1 showed considerably more motional freedom than on phenylalanine B-1. Guanidine hydrochloride and sodium dodecyl sulfate were used to study the unfolding of several trifluoroacetylinsulin derivatives. The results suggested differential alterations in the environments of the probes located at glycine A-1, phenylalanine B-1, and lysine B-29 in the insulin molecule as the concentration of perturbant was increased.     

Altered Glycoflavone expression in induced Autotetraploids of Phlox drummondii

The effects of colchicine induced autotetraploidy on non-anthocyanin flavonoid expression were determine for 15 cultivars of Phlox drummondii and for the naturally occuring P. drummondii ssp. mcallisteri. Collectively, the taxa express a total of nine glycoflavonoid derivatives (C, O-diglycosides or di-C-glycosides) of either apigenin or luteolin. The autotetraploids of 14 cultivars and those of the natural subspecies exhibit altered glycoflavone profiles relative to their respective diploid sources. The qualitative alternations in the cultivars may be grouped into three phenotypic categories: (1) the expression of novel glycoflavones, (2) the absence of diploid glycoflavones, and (3) the deregulation of tissue-specific glycoflavone production. Alterations in mcallisteri autotetraploids include only the latter two categories. Each of the novel compounds is otherwise expressed among other diploid cultivars or in other wild P. drummondii subspecies. Quantitatively, the phenolic content of most autotetraploid flowers is significantly greater than in respective diploid flowers. However, on a dry weight basis, phenolic titre in comparable 4n and 2n floral or leaf tissues is not significantly different. Floral tissues express from 5 to 10 times the phenolic titre of leaves. The results are discussed in terms of the possible origins of novel flavonoids in natural polyploid Phlox species.     

Relation of tegumentary phosphohydrolase to purine and pyrimidine transport in Schistosoma mansoni.

Inhibition of the saturable influx of 0.05 mM 14C-labeled adenine or adenosine by AMP in adult Schistosoma mansoni in vitro suggested hydrolysis of this nucleotide at the tegumental surface of the parasite. Adenosine liberated as a result of AMP hydrolysis was the inhibitor of uptake of labeled adenine or adenosine. Inhibition of adenosine uptake by AMP or ATP was relieved by paranitrophenyl phosphate or ammonium molybdate supporting the hypothesis of nucleotide hydrolysis at the tengumental surface. Addition of glucose-1-phosphate, glucose-6-phosphate, NaF, or cysteine did not relieve AMP inhibition of adenosine uptake indicating substrate and inhibitor specificity for the surface enzyme(s). AMP, ATP, UMP, and p-nitrophenyl are hydrolyzed, at least in part, by the same enzyme(s). Apparent absorption of labeled AMP was preceded by hydrolysis, with labeled adenosine as the actual compound absorbed, although there was a small diffusion component for absorption of intact AMP. The site of nucleotide hydrolysis in close proximity to absorption sites provides a kinetic advantage for uptake of products of adenine nucleotide hydrolysis but not for products of uracil nucleotide hydrolysis.     

Plasmodium berghei leucine-rich repeat protein 1 downregulates protein phosphatase 1 activity and is required for efficient oocyst development

Protein phosphatase 1 (PP1) is a key enzyme for Plasmodium development. However, the detailed mechanisms underlying its regulation remain to be deciphered. Here, we report the functional characterization of the Plasmodium berghei leucine-rich repeat protein 1 (PbLRR1), an orthologue of SDS22, one of the most ancient and conserved PP1 interactors. Our study shows that PbLRR1 is expressed during intra-erythrocytic development of the parasite, and up to the zygote stage in mosquitoes. PbLRR1 can be found in complex with PbPP1 in both asexual and sexual stages and inhibits its phosphatase activity. Genetic analysis demonstrates that PbLRR1 depletion adversely affects the development of oocysts. PbLRR1 interactome analysis associated with phospho-proteomics studies identifies several novel putative PbLRR1/PbPP1 partners. Some of these partners have previously been characterized as essential for the parasite sexual development. Interestingly, and for the first time, Inhibitor 3 (I3), a well-known and direct interactant of Plasmodium PP1, was found to be drastically hypophosphorylated in PbLRR1-depleted parasites. These data, along with the detection of I3 with PP1 in the LRR1 interactome, strongly suggest that the phosphorylation status of PbI3 is under the control of the PP1–LRR1 complex and could contribute (in)directly to oocyst development. This study provides new insights into previously unrecognized PbPP1 fine regulation of Plasmodium oocyst development through its interaction with PbLRR1.     

A physiological and molecular study of the effects of nickel deficiency and phenylphosphorodiamidate (PPD) application on urea metabolism in oilseed rape (Brassica napus L.)

Background and aims

Urea is the major nitrogen (N) form supplied as fertilizer in agriculture. However, urease, a nickel-dependent enzyme, allows plants to use external or internally generated urea as a nitrogen source. Since a urease inhibitor is frequently applied in conjunction with urea fertilizer, the N-metabolism of plants may be affected. The aim of this study was to determine physiological and molecular effects of nickel deficiency and a urease inhibitor on urea uptake and assimilation in oilseed rape.

Methods

Plants were grown on hydroponic solution with urea as the sole N source under three treatments: plants treated with nickel (+Ni) as a control, without nickel (?Ni) and with nickel and phenylphosphorodiamidate (+Ni+PPD). Urea transport and assimilation were investigated.

Results

The results show that Ni-deficiency or PPD supply led to reduced growth and reduced ¹⁵N-uptake from urea. This effect was more pronounced in PPD-treated plants, which accumulated high amounts of urea and ammonium. Thus, Ni-deficiency or addition of PPD, limit the availability of N and decreased shoot and root amino acid content. The up-regulation of BnDUR3 in roots indicated that this gene is a component of the stress response to nitrogen-deficiency. A general decline of glutamine synthetase (GS) activity and activation of glutamate dehydrogenase (GDH) and increases in its expression level were observed in control plants. At the same time, in (?N) or (+Ni+PPD) treated plants, no increases in GS or GDH activities and expression level were found.

Conclusions

Overall results showed that plants require Ni as a nutrient (while most widely used nutrient solutions are devoid of Ni), whether they are grown with or without a urea supply, and that urease inhibitors may have deleterious effects at least in hydroponic grown oilseed rape.     

Ants impact the composition of the aquatic macroinvertebrate communities of a myrmecophytic tank bromeliad

In an inundated Mexican forest, 89 out of 92 myrmecophytic tank bromeliads (Aechmea bracteata) housed an associated ant colony: 13 sheltered Azteca serica, 43 Dolichoderus bispinosus, and 33 Neoponera villosa. Ant presence has a positive impact on the diversity of the aquatic macroinvertebrate communities (n = 30 bromeliads studied). A Principal Component Analysis (PCA) showed that the presence and the species of ant are not correlated to bromeliad size, quantity of water, number of wells, filtered organic matter or incident radiation. The PCA and a generalized linear model showed that the presence of Azteca serica differed from the presence of the other two ant species or no ants in its effects on the aquatic invertebrate community (more predators). Therefore, both ant presence and species of ant affect the composition of the aquatic macroinvertebrate communities in the tanks of A. bracteata, likely due to ant deposition of feces and other waste in these tanks.     

Key Elements in a Framework for Land Use Impact Assessment Within LCA (11 pp)

Background, Aim and Scope Land use by agriculture, forestry, mining, house-building or industry leads to substantial impacts, particularly on biodiversity and on soil quality as a supplier of life support functions. Unfortunately there is no widely accepted assessment method so far for land use impacts. This paper presents an attempt, within the UNEP-SETAC Life Cycle Initiative, to provide a framework for the Life Cycle Impact Assessment (LCIA) of land use. Materials and Methods: This framework builds from previous documents, particularly the SETAC book on LCIA (Lindeijer et al. 2002), developing essential issues such as the reference for occupation impacts; the impact pathways to be included in the analysis; the units of measure in the impact mechanism (land use interventions to impacts); the ways to deal with impacts in the future; and bio-geographical differentiation. Results: The paper describes the selected impact pathways, linking the land use elementary flows (occupation; transformation) and parameters (intensity) registered in the inventory (LCI) to the midpoint impact indicators and to the relevant damage categories (natural environment and natural resources). An impact occurs when the land properties are modified (transformation) and also when the current man-made properties are maintained (occupation). Discussion: The size of impact is the difference between the effect on land quality from the studied case of land use and a suitable reference land use on the same area (dynamic reference situation). The impact depends not only on the type of land use (including coverage and intensity) but is also heavily influenced by the bio-geographical conditions of the area. The time lag between the land use intervention and the impact may be large; thus land use impacts should be calculated over a reasonable time period after the actual land use finishes, at least until a new steady state in land quality is reached. Conclusions: Guidance is provided on the definition of the dynamic reference situation and on methods and time frame to assess the impacts occurring after the actual land use. Including the occupation impacts acknowledges that humans are not the sole users of land. Recommendations and Perspectives: The main damages affected by land use that should be considered by any method to assess land use impacts in LCIA are: biodiversity (existence value); biotic production potential (including soil fertility and use value of biodiversity); ecological soil quality (including life support functions of soil other than biotic production potential). Bio-geographical differentiation is required for land use impacts, because the same intervention may have different consequences depending on the sensitivity and inherent land quality of the environment where it occurs. For the moment, an indication of how such task could be done and likely bio-geographical parameters to be considered are suggested. The recommendation of indicators for the suggested impact categories is a matter of future research.     

Application of silica aerogel encapsulated lipases in the synthesis of biodiesel by transesterification reactions

Two types of commercial lipases preparations, one from Burkholderia cepacia, the other one from Candida antartica, were encapsulated in silica aerogels reinforced with silica quartz fibre felt and dried by the CO₂ supercritical technique. These immobilized biocatalysts were applied in biodiesel synthesis by transesterification of sunflower seed oil with methyl acetate. They were found to be efficient even with mixtures of both substrates without any solvent addition. The aerogel encapsulation technique made it possible to maintain the enzymes in a dispersion state similar to the dispersion prevailing in an aqueous solution, even for further use in organic hydrophobic media. In transesterification in excess iso-octane, the two lipases encapsulated in aerogels made from 40% MTMS, were found to have activities relatively close to each other and comparable with commercial Novozyme 435. On the other in transesterification with mixture of oil and methyl acetate without any solvent, the kinetics were severely limited by substrate diffusion inside the aerogels. This was particularly true with the C. antartica, so that the corresponding aerogel encapsulated enzyme was much less active than commercial Novozyme 435, although it improved after a few tests.