The expression in E. coli of a polymeric gene coding for an esterase mimic catalyzing the hydrolysis of p-nitrophenyl esters

We have prepared a hybrid protein consisting of seven esterase units, Glu-Ala-His-Ala-Ser-Phe-Phe-Phe, fused to the N-terminal of galactokinase (E. coli). The structural gene for this bifunctional protein was obtained by cloning a polymer made up of three chemically synthesized oligonucleotides to which the galactokinase gene was fused in frame. The hybrid protein was purified to homogeneity with the aid of the galactokinase moiety and showed an M_r of 51 000-53 000. The preparation could catalyze the hydrolysis of p-nitrophenyl esters and, due to the inbuilt hydrophobic spacers, Phe-Phe-Phe, improved catalysis of more hydrophobic substrates was obtained.     

Role of aspartate aminotransferase and mitochondrial dicarboxylate transport for release of endogenously and exogenously supplied neurotransmitter in glutamatergic neurons

Evoked release of glutamate and aspartate from cultured cerebellar granule cells was studied after preincubation of the cells in tissue culture medium with glucose (6.5 mM), glutamine (1.0 mM),d[³H] aspartate and in some cases aminooxyacetate (5.0 mM) or phenylsuccinate (5.0 mM). The release of endogenous amino acids and ofd-[³H] aspartate was measured under physiological and depolarizing (56 mM KCl) conditions both in the presence and absence of calcium (1.0 mM), glutamine (1.0 mM), aminooxyacetate (5.0 mM) and phenylsuccinate (5.0 mM). The cellular content of glutamate and aspartate was also determined. Of the endogenous amino acids only glutamate was released in a transmitter fashion and newly synthesized glutamate was released preferentially to exogenously suppliedd-[³H] aspartate, a marker for exogenous glutamate. Evoked release of endogenous glutamate was reduced or completely abolished by respectively, aminooxyacetate and phenylsuccinate. In contrast, the release ofd-[³H] aspartate was increased reflecting an unaffected release of exogenous glutamate and an increased psuedospecific radioactivity of the glutamate transmitter pool. Since aminooxyacetate and phenylsuccinate inhibit respectively aspartate aminotransferase and mitochondrial keto-dicarboxylic acid transport it is concluded that replenishment of the glutamate transmitter pool from glutamine, formed in the mitochondrial compartment by the action of glutaminase requires the simultaneous operation of mitochondrial keto-dicarboxylic acid transport and aspartate aminotransferase which is localized both intra- and extra-mitochondrially. The purpose of the latter enzyme apparently is to catalyze both intra- and extra-mitochondrial transamination of -ketoglutarate which is formed intramitochondrially from the glutamate carbon skeleton and transferred across the mitochondrial membrane to the cytosol where transmitter glutamate is formed. This cytoplasmic origin of transmitter glutamate is in aggreement with the finding thatd-[³H] aspartate readily labels the transmitter pool even when synthesis of endogenous transmitter is impaired in the presence of AOAA or phenylsuccinate.Special issue dedicated to Dr Elling Kvamme     

Simple Preparation of Rhodococcus erythropolis DSM 44534 as Biocatalyst to Oxidize Diols into the Optically Active Lactones

In the current study, we present a green toolbox to produce ecological compounds like lactone moiety. Rhodococcus erythropolis DSM 44534 cells have been used to oxidize both decane‐1,4‐diol ( 2a ) and decane‐1,5‐diol ( 3a ) into the corresponding γ‐ ( 2b ) and δ‐decalactones ( 3b ) with yield of 80% and enantiomeric excess (ee) = 75% and ee = 90%, respectively. Among oxidation of meso diols, (?)‐(1S,5R)‐cis‐3‐oxabicyclo[4.3.0]non‐7‐en‐2‐one ( 5a ) with 56% yield and ee = 76% as well as (?)‐(2R,3S)‐cis‐endo‐3‐oxabicyclo[2.2.1]dec‐7‐en‐2‐one ( 6a ) with 100% yield and ee = 90% were formed. It is worth mentioning that R. erythropolis DSM 44534 grew in a mineral medium containing ethanol as the sole source of energy and carbon Chirality 28:623–627, 2016. © 2016 Wiley Periodicals, Inc.     

V/Q distribution and correlation to atelectasis in anesthetized paralyzed humans

Tokics, Leif, Göran Hedenstierna, Leif Svensson, BoBrismar, Torsten Cederlund, Hans Lundquist, and ÅkeStrandberg. / distributionand correlation to atelectasis in anesthetized paralyzed humans.J. Appl. Physiol. 81(4):1822-1833, 1996.Regional ventilation and perfusion were studiedin 10 anesthetized paralyzed supine patients by single-photon emissioncomputerized tomography. Atelectasis was estimated from twotransaxial computerized tomography scans. The ventilation-perfusion(/) distribution was alsoevaluated by multiple inert gas elimination. While the patients wereawake, inert gas / ratio wasnormal, and shunt did not exceed 1% in any patient. Computerizedtomography showed no atelectasis. During anesthesia, shunt ranged from0.4 to 12.2%. Nine patients displayed atelectasis (0.6-7.2% ofthe intrathoracic area), and shunt correlated with the atelectasis(r = 0.91, P < 0.001). Shunt was located independent lung regions corresponding to the atelectatic area. There wasconsiderable / mismatch, withventilation mainly of ventral lung regions and perfusion of dorsalregions. Little perfusion was seen in the most ventral parts (zone 1)of caudal (diaphragmatic) lung regions. In summary, shunt during anesthesia is due to atelectasis in dependent lung regions. The / distributions differ fromthose shown earlier in awake subjects.

     

Confined-pyrolysis as an experimental method for hydrothermal organic synthesis

A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H₂O and D₂O elucidated the isomerization and hydrogenation reactions of aliphatic compounds and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.     

Bacterial NADH-quinone oxidoreductases: Iron-sulfur clusters and related problems

Many bacteria contain proton-translocating membrane-bound NADH-quinone oxidoreductases (NDH-1), which demonstrate significant genetic, spectral, and kinetic similarity with their mitochondrial counterparts. This review is devoted to the comparative aspects of the ironsulfur cluster composition of NDH-1 from the most well-studied bacterial systems to date.:Paracoccus denitrificans, Rhodobacter sphaeroides, Escherichia coli, andThermus thermophilus. These bacterial systems provide useful models for the study of coupling Site I and contain all the essential parts of the electron-transfer and proton-translocating machinery of their eukaryotic counterparts.     

Interleukin-2-administration intravenously and intrapleurally in a patient with primary pulmonary adenocarcinoma. Cellular responses in peripheral blood,intrapleural fluid and bronchoalveolar lavage

A case report of a patient who suffered from a rapidly progressive lung adenocarcinoma with malignant pleural effusions, is given. The patient failed to respond on two series of conventional cytotoxic drug therapy (Carboplatin, Etoposid). Interleukin-2 (IL-2) treatment was first started as intrapleural instillations (3.0 million IU per day in 6 days). A clear clinical response was achieved with ceasing of the pleural effusion, and the overall disease became stable. In the peripheral blood, there was an increase of CD₄ positive lymphocytes that remained elevated after finishing the installation period. Both in bronchoalveolar lavage (BAL), and in the pleural fluid, there was a marked decrease of cells recovered, possibly due to an enhanced tissue attachment of activated cells. A second analysis with subtyping of lymphocytes in BAL was impossible due to the low cell number. In the pleural fluid, the fractions of CD₃ positive cells increased from 20 to 71% while the ratio between CD₄ and CD₈ remained persistently elevated at 6.11. Because of the disappearance of the pleural effusion, the patient was thereafter treated with IL-2 given as a continuous infusion (18 million IU per square-metre during 24 hours for 5 days). Hereby a more pronounced cell response was achieved in the peripheral blood. In contrast to the intrapleural treatment route, not only CD₄ positive cells, but also the numbers of natural killer cells (NK) increased. However this treatment was also associated with a much higher degree of side effects. It can be concluded from both intrapleural and intravenous IL-2 therapy, that a clinical and immunological response was achieved. As this type of tumour is well known to respond poorly to conventional therapy, treatment with biological modifiers such as IL-2 may offer an interesting alternative in the future.Abbreviations BAL bronchoalveolar lavage - K-2 Interleukin-2     

Tree limit dynamics of Betula pubescens ssp. tortuosa in relation to climate variability: evidence from central Sweden

Abstract. The tree limit of Betula pubescens ssp. tortuosa (mountain birch) in the southern Swedish Scandes was monitored during 1972–1992. The study included various aspects of growth, vigour and reproduction of Betula. The main focus was on the character and mechanics of the tree limit/climate equilibrium system. The tree limit, which changed in response to a temperature rise early this century, remained constant in position and tree physiognomy did not change, although the past 50 yr or so have been colder. Indeed, growth and reproductive effort and capacity decreased in this period. Obviously, most resources in Betula were used to resist stress in the mature phase, resulting in delayed recession of trees. Unless drastic warming occurs, stem dieback is predicted for the near future. Even a minorclimatic disturbance would have an effect, because resources are gradually being depleted. Radial growth correlated most closely with the mean temperature in July. Particularly at the present-day tree limit, the variance in annual growth could be largely explained by climatic factors. The hypothesis is that long-term tree limit dynamics during the late Holocene is merely a matter of fluctuations in vegetative vigour and stature of old individuals. At the population level, response to climatic variability appears to be greatly delayed.     

The dominant mutation Suppressor of black indicates that de novo pyrimidine biosynthesis is involved in the Drosophila tan pigmentation pathway

A deficiency in the production of β-alanine causes the black (b) phenotype of Drosophila melanogaster. This phenotype is normalized by a semi-dominant mutant gene Su(b) shown previously to be located adjacent to or within the rudimentary (r) locus. The r gene codes for three enzyme activities involved in de novo pyrimidine biosynthesis. Pyrimidines are known to give rise to β-alanine. However, until recently it has been unclear whether de novo pyrimidine biosynthesis is directly coupled to β-alanine synthesis during the tanning process. In this report we show that flies carrying Su(b) can exhibit an additional phenotype, resistance to toxic pyrimidine analogs (5-fluorouracil, 6-azathymine and 6-azauracil). Our interpretation of this observation is that the pyrimidine pool is elevated in the mutant flies. However, enzyme assays indicate that r enzyme activities are not increased in Su(b) flies. Genetic mapping of the Su(b) gene now places the mutation within the r gene, possibly in the carbamyl phosphate synthetase (CPSase) domain. The kinetics of CPSase activity in crude extracts has been studied in the presence of uridine triphosphate (UTP). While CPSase from wild-type flies was strongly inhibited by the end-product, UTP, CPSase from Su(b) was inhibited to a lesser extent. We propose that diminished end-product inhibition of de novo pyrimidine biosynthesis in Su(b) flies increases available pyrimidine and consequently the β-alanine pool. Normalization of the black phenotype results.     

Lifecycle climate impact and primary energy use of electric and biofuel cargo trucks

Heavy trucks contribute significantly to climate change, and in 2020 were responsible for 7% of total Swedish GHG emissions and 5% of total global CO₂ emissions. Here we study the full lifecycle of cargo trucks powered by different energy pathways, comparing their biomass feedstock use, primary energy use, net biogenic and fossil CO₂ emission and cumulative radiative forcing. We analyse battery electric trucks with bioelectricity from stand-alone or combined heat and power (CHP) plants, and pathways where bioelectricity is integrated with wind and solar electricity. We analyse trucks operated on fossil diesel fuel and on dimethyl ether (DME). All energy pathways are analysed with and without carbon capture and storage (CCS). Bioelectricity and DME are produced from forest harvest residues. Forest biomass is a limited resource, so in a scenario analysis we allocate a fixed amount of biomass to power Swedish truck transport. Battery lifespan and chemistry, the technology level of energy supply, and the biomass source and transport distance are all varied to understand how sensitive the results are to these parameters. We find that pathways using electricity to power battery electric trucks have much lower climate impacts and primary energy use, compared to diesel- and DME-based pathways. The pathways using bioelectricity with CCS result in negative emissions leading to global cooling of the earth. The pathways using diesel and DME have significant and very similar climate impact, even with CCS. The robust results show that truck electrification and increased renewable electricity production is a much better strategy to reduce the climate impact of cargo transport than the adoption of DME trucks, and much more primary energy efficient. This climate impact analysis includes all fossil and net biogenic CO₂ emissions as well as the timing of these emissions. Considering only fossil emissions is incomplete and could be misleading.