Metabolic Costs of Feeding Predictively Alter the Spatial Distribution of Individuals in Fish Schools

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Three AtCesA6‐like members enhance biomass production by distinctively promoting cell growth in Arabidopsis

Cellulose is an abundant biopolymer and a prominent constituent of plant cell walls. Cellulose is also a central component to plant morphogenesis and contributes the bulk of a plant's biomass. While cellulose synthase (CesA) genes were identified over two decades ago, genetic manipulation of this family to enhance cellulose production has remained difficult. In this study, we show that increasing the expression levels of the three primary cell wall AtCesA6‐like genes (AtCesA2, AtCesA5, AtCesA6), but not AtCesA3, AtCesA9 or secondary cell wall AtCesA7, can promote the expression of major primary wall CesA genes to accelerate primary wall CesA complex (cellulose synthase complexes, CSCs) particle movement for acquiring long microfibrils and consequently increasing cellulose production in Arabidopsis transgenic lines, as compared with wild‐type. The overexpression transgenic lines displayed changes in expression of genes related to cell growth and proliferation, perhaps explaining the enhanced growth of the transgenic seedlings. Notably, overexpression of the three AtCesA6‐like genes also enhanced secondary cell wall deposition that led to improved mechanical strength and higher biomass production in transgenic mature plants. Hence, we propose that overexpression of certain AtCesA genes can provide a biotechnological approach to increase cellulose synthesis and biomass accumulation in transgenic plants.     

Muddy odour: a problem associated with extreme eutrophication

The results of a 4-year study in a hypereutrophic bay, Kaupunginselkä Bay at Porvoo on the south coast of Finland, indicated a significant correlation between muddy odour in bream (Abramis brama) and the amount of the blue-green alga Oscillatoria agardhii in the phytoplankton. This algal strain has previously been shown to produce the muddy-smelling compound geosmin. The numbers of muddy-smelling actinomycetes in the water and sediments of the study area were not clearly related to muddy odour in fish, nor to phytoplankton biomass. In the hypereutrophic L. Tuusulanjärvi, muddy odour in bream and pikeperch (Stizostedion lucioperca) was also related to the amounts of blue-green algae in the phytoplankton.     

Differentiation between bronchodilation and universal adenosine antagonism among xanthine derivatives

Relaxant effects and adenosine-antagonism of 3-propyl-xanthine (enprofylline) and 10 different methyl-xanthines were examined in isolated guinea-pig tracheas. The chemical structural requirements for tracheal relaxation were found to be different from those for adenosine antagonism by the xanthine derivatives. All xanthines produced relaxation: Enprofylline was about 5 times more potent than theophylline. However, only xanthines with a methyl in the 1-position consistently antagonized the relaxant effect of adenosine. --Theophylline over a wide range of concentrations (30-900 microM) produced a concentration dependent and surmountable antagonism at nervous adenosine receptors (isolated guinea-pig myenteric-plexus preparations). The same concentrations of enprofylline were almost devoid of antagonism at these adenosine receptors. In mice theophylline (6-24 mg/kg given intraperitoneally) dose-dependently increased locomotor activity while enprofylline (2-48 mg/Kg) was without effect on behaviour. "Non-blocking" xanthines such as enprofylline may be potent bronchodilators but lack many theophylline-like actions. We, therefore, forward the hypothesis that universal adenosine antagonism is both unnecessary and undesirable with xanthine antiasthmatics.     

Enchytraeids, lumbricids and soil arthropods in a northern deciduous woodland – a quantitative study

Soil/litter inhabiting annelids and arthropods were studied for one year in a mesic deciduous woodland, Andersby ängsbackar, one of the most northerly areas in Sweden to possess unbroken oak/hazel vegetation. Lumbricidae, Enchytraeidae, Collembola, Acari, Coleoptera, Diptera and Araneae were important faunal groups with regard to abundance, biomass and respiratory metabolism. Annual mean biomass (8 g dw m⁻²) and respiration (450 kJ m ⁻² yr⁻¹) of the joint annelid and arthropod community were dominated by lumbricids (76 and 50%, respectively). The biomass and respiration of the annelids and arthropods at Andersby were lower than in some other oak forests in northwestern Europe, probably because of lower soil temperature, lower litter supply and because some lumbricid and diplopod species were at their northern border of distribution.
Of the annual respiration, saprovores, fungivores, carnivores and root-feeders contributed 65, 19, 14 and 1.5%, respectively. The saprovore percentage was lower at Andersby than at other mull sites compared, probably as an effect of the northern climate, which might favour microbial saprovory. The fungivore and carnivore percentages were higher, which might be due to the presence of a litter layer throughout the year.     

Cr(III)-Induced polymerization of human albumin

Chromium (III)-albumin complexes that have allergenic properties and induce contact dermatitis are aggregated in solution. This is shown by small-angle X-ray scattering of Cr(III)-albumin solutions at 21°C in a Tris-HCl buffer of pH=7.40. At high concentrations of Cr(III), albumin appears to aggregate to an average molecular weight of an octamer, with an average gyration radius of 116 Å. At low concentration of Cr(III), dimers and also some higher polymers form with an average molecular weight of 135,000 and an average radius of gyration of 57 Å. Analysis of the shapes of the Cr(III)-albumin complexes indicate that they are more elongated than albumin, suggesting that, in the presence of Cr(III), the albumin molecules associate sideways with an expansion mainly of the largest axis.     

Epidural Analgesia in Dogs with Special Reference to the Intraarterial Blood Pressure

In order to investigate whether epidural analgesia in dogs employing mepivacaine chloride gives rise to complications, mainly changes in blood pressure, such analgesia was carried out in 35 dogs brought to the clinic for orthopedic, abdominal or perineal operations. Intra-arterial blood pressure measurements were made in 16 dogs. Three different solutions of mepivacaine chloride were used: 1 % solution with adrenaline 1:200,000; 2% solution with adrenaline 1:100,000 and 2% solution with adrenaline 1:200,000. The various solutions showed no significant difference in analgesic effect. Nor was any blood pressure change found during the epidural blockade. As a solution with a higher concentration causes a higher blood level of the analgesic and also greater toxic effects it is recommended that first preference be given to use of a 1 % solution with adrenaline 1:200,000; second choice is a 2 % solution with adrenaline 1:200,000 and third choice the 2 % solution with adrenaline 1:100,000.     

A novel ribosome-associated protein is important for efficient translation in Escherichia coli.

Previously, we showed that strains which have been deleted for the 21K gene (hereafter called yfjA), of the trmD operon, encoding a 21-kDa protein (21K protein) have an approximately fivefold-reduced growth rate in rich medium. Here we show that such mutants show an up to sevenfold reduced growth rate in minimal medium, a twofold-lower cell yield-to-carbon source concentration ratio, and a reduced polypeptide chain growth rate of beta-galactosidase. Suppressor mutations that increased the growth rate and translational efficiency of a delta yfjA mutant were localized to the 3' part of rpsM, encoding ribosomal protein S13. The 21K protein was shown to have affinity for free 30S ribosomal subunits but not for 70S ribosomes. Further, the 21K protein seems to contain a KH domain and a KOW motif, both suggested to be involved in binding of RNA. These findings suggest that the 21K protein is essential for a proper function of the ribosome and is involved in the maturation of the ribosomal 30S subunits or in translation initiation.     

The spoU gene of Escherichia coli, the fourth gene of the spoT operon, is essential for tRNA (Gm18) 2'-O-methyltransferase activity.

We have evidence that the open reading frame previously denoted spoU is necessary for tRNA (Gm18) 2'-O-methyltransferase activity. The spoU gene is located in the gmk-rpoZ-spoT-spoU-recG operon at 82 minutes on the Escherichia coli chromosome. The deduced amino acid sequence of spoU shows strong similarities to previously characterized 2'-O-methyltransferases. Comparison of the nucleoside modification pattern of hydrolyzed tRNA, 16S rRNA and 23S rRNA from wild-type and spoU null mutants showed that the modified nucleoside 2'-O-methylguanosine (Gm), present in a subset of E. coli tRNAs at residue 18, is completely absent in the spoU mutant, suggesting that spoU encodes tRNA (Gm18) 2'-O-methyltransferase. Nucleoside modification of 16S and 23S rRNA was unaffected in the spoU mutant. Insertions in the downstream recG gene did not affect RNA modification. Absence of Gm18 in tRNA does not influence growth rate under the tested conditions and does not interfere with activity of the SupF amber suppressor, a suppressor tRNA that normally has the Gm18 modification. We suggest that the spoU gene be renamed trmH (tRNA methylation).     

Monosialoganglioside (GM1) immunofluorescence in rat spinal roots studied with a monoclonal antibody

Gangliosides are characteristic glycolipid components of plasma cell membranes, especially enriched in the CNS and PNS. In some diseases involving the PNS, in particular motor neuropathies associated with conduction block, IgM autoantibodies against ganglioside GM1 have been implicated as a pathogenic factor. In order to study the GM1 distribution in peripheral nerves we have investigated its in situ localization using a new anti-GM1 monoclonal antibody, GM1:1. Immunization and production of the monoclonal antibody was made by common protocols and binding specificity was investigated by using structurally related glycolipids and modified GM1-molecules. The result showed that an α2–3 bound sialic acid together with a terminal galactose moiety were essential for GM1:1 binding. In situ localization of GM1 in rat dorsal and ventral spinal roots was investigated by conventional immunomicroscopy. GM1 immunoreactivity was the same in both roots and appeared like a finely granular, in places confluent, material confined to Schmidt-Lanterman’s incisures, to myelin sheath paranodal end segments and to some extent to the abaxonal Schwann cell cytoplasm; all of these structures are likely to be the target for GM1 antibodies in peripheral neuropathies. Nodal gaps and fibre contours showed a weak non-specific fluorescence. The localization of GM1 to the incisures of Schmidt-Lanterman and the paranodal end segments of the myelin sheaths might indicate a role of gangliosides as adhesion molecules.