The cellulosome and cellulose degradation by anaerobic bacteria.

Despite its simple chemical composition, cellulose exists in a number of crystalline and amorphous topologies. Its insolubility and heterogeneity makes native cellulose a recalcitrant substrate for enzymatic hydrolysis. Microorganisms meet this challenge with the aid of a multi-enzyme system.

On the Interpretation of Response Time vs Onset Asynchrony Functions: Application to Dual-Task and Precue-Utilization Paradigms.

The central bottleneck model of dual-task performance (H. Pashler and J. C.

The binding pattern of two carbohydrate-binding modules of laminarinase Lam16A from Thermotoga neapolitana: differences in beta-glucan binding within family CBM4.

Carbohydrate-binding modules (CBMs) are often part of the complex hydrolytic extracellular enzymes from bacteria and may modulate their catalytic activity. The thermostable catalytic domain of laminarinase Lam16A from Thermotoga neapolitana (glycosyl hydrolase family 16) is flanked by two CBMs, 148 and 161 aa long. They share a sequence identity of 30%, are homologous to family CBM4 and are thus called CBM4-1 and CBM4-2 respectively.

[Contrast medium enhanced magnetic resonance tomography of liver metastases: positive versus negative contrast media].

The development in oncologic liver surgery as well as modified interventional therapy strategies of the liver have resulted in improved diagnostic imaging. The evolution of contrast agents for MR imaging of the liver has proceeded along several different paths with the common goal of improving liver-lesion contrast. In MRI contrast agents act indirectly by their effects on relaxation times.

Molecular characterization of co-transcribed genes from Streptomyces tendae Tü901 involved in the biosynthesis of the peptidyl moiety and assembly of the peptidyl nucleoside antibiotic nikkomycin.

Six genes (nikP1, nikP2, nikS, nikT, nikU, and nikV) from Streptomyces tendae Tu901 were identified by analysis of the nucleotide sequence of the nikkomycin gene cluster. These genes, together with the previously described nikQ and nikR, span 9.39 kb and are transcribed as a polycistronic mRNA in a growth-phase-dependent manner.

[Percutaneous transvenous recovery of foreign bodies using a self-made wire loop].

Aim: Several techniques exist to retrieve catheter and guide wire fragments. In this report we summarize our cost-saving method.

Materials And Methods: A 7-8F guiding catheter and a self-made loop consisting of a 260 cm/0.

Extracellular pH modulates kinetics of the Na(+),K(+)-ATPase.

To investigate effects of pH on the Na(+),K(+)-ATPase, we used the Xenopus oocytes to measure transient charge movements in the absence of extracellular K(+), and steady-state currents mediated by the pump as well as ATPase activity. The activity of purified Na(+), K(+)-ATPase strongly depends on pH, which has been attributed to protonation of intracellular sites. The steady-state current reflects pump activity, the transient charge movement voltage-dependent interaction of external Na(+) ions with the pump molecule and/or conformational changes during Na(+)/Na(+) exchange.

Sequential effects in number comparison.

The modular framework of number processing (e.g., S.

Functional significance of N- and C-terminus of the amino acid transporters EAAC1 and ASCT1: characterization of chimeric transporters.

To localize functionally significant domains in the amino acid transporters of mouse brain mEAAC1 and mASCT1, cRNA encoding for wild-type and chimeric transporters was injected into Xenopus oocytes. Activity of expressed transporters was investigated by measurements of uptake of 3H-labeled glutamate and serine and of glutamate- and serine-induced currents under voltage clamp. Though all transporters accept glutamate and serine as substrate, the central part of the protein (Ala94-Met418 of mEAAC1 and Ala119-Ile393 of mASCT1) determines substrate selectivity.

Isolation of mesophilic solvent-producing clostridia from Colombian sources: physiological characterization, solvent production and polysaccharide hydrolysis.

One hundred and seventy-eight new butanol-acetone producing bacteria related to saccharolytic clostridia were isolated from agricultural sources in Colombia and their fermentation potential was evaluated. Thirteen isolates produced more total solvents from glucose than Clostridium acetobutylicum ATCC 824. The isolates with the highest single solvent production were IBUN 125C and IBUN 18A with 0.

Trypanosomes lacking trypanothione reductase are avirulent and show increased sensitivity to oxidative stress.

In Kinetoplastida, trypanothione and trypanothione reductase (TRYR) provide an intracellular reducing environment, substituting for the glutathione-glutathione reductase system found in most other organisms. To investigate the physiological role of TRYR in Trypanosoma brucei, we generated cells containing just one trypanothione reductase gene, TRYR, which was under the control of a tetracycline-inducible promoter. This enabled us to regulate TRYR activity in the cells from less than 1% to 400% of wild-type levels by adjusting the concentration of added tetracycline.

The thermostable alpha-L-rhamnosidase RamA of Clostridium stercorarium: biochemical characterization and primary structure of a bacterial alpha-L-rhamnoside hydrolase, a new type of inverting glycoside hydrolase.

An alpha-L-rhamnosidase clone was isolated from a genomic library of the thermophilic anaerobic bacterium Clostridium stercorarium and its primary structure was determined. The recombinant gene product, RamA, was expressed in Escherichia coli, purified to homogeneity and characterized. It is a dimer of two identical subunits with a monomeric molecular mass of 95 kDa in SDS polyacrylamide gel electrophoresis.

Molecular characterization of co-transcribed genes from Streptomyces tendae Tü901 involved in the biosynthesis of the peptidyl moiety of the peptidyl nucleoside antibiotic nikkomycin.

Six genes (nikA, nikB, nikD, nikE, nikF, and nikG) from Streptomyces tendae Tü901 were identified by sequencing the region surrounding the nikC gene, which encodes L-lysine 2-aminotransferase, previously shown to catalyze the initial reaction in the biosynthesis of hydroxypyridylhomothreonine, the peptidyl moiety of the peptidyl nucleoside antibiotic nikkomycin. These genes, together with the nikC gene, span a DNA region of 7.87 kb and are transcribed as a polycistronic mRNA in a growth-phase dependent manner.

Inhibition of uptake, steady-state currents, and transient charge movements generated by the neuronal GABA transporter by various anticonvulsant drugs.

1. We have expressed the GABA transporter (GAT1) of mouse brain in Xenopus oocytes and have investigated the effects of four antiepileptic drugs, tiagabine (TGB), vigabatrin (VGB), gabapentin (GBP) and valproate (VAL), on GAT1 transporter function by measurements of 3H-labelled GABA uptake and GAT1-mediated currents. 2.

Duplicated Clostridium thermocellum cellobiohydrolase gene encoding cellulosomal subunits S3 and S5.

The upstream region of the cellobiohydrolase gene cbhA of Clostridium thermocellum F7 was sequenced. It was found that this region contains the previously sequenced gene celK encoding an enzyme closely related to CbhA (cellulosomal subunit S3). The presence of a putative transcription terminator in the 524-bp intergenic region indicates that celK and cbhA are not cotranscribed as an operon.

Experimental investigation of oscillatory flow through a symmetrically bifurcating tube.

To provide a quantitative description of the convection field of gas transport through the lung under both low and high-frequency ventilation conditions, volume-cycled, purely oscillatory flow has been investigated in a symmetrically bifurcating model bronchial bifurcation. Significant differences in the flow properties that developed as the Reynolds number varied from 750 to 950 and the dimensionless frequency varied from 3 to 12 are described. At low frequency, the axial velocity field was found to approximate closely that of a steady flow through a bifurcation.

Organization of the chromosomal region containing the genes lexA and topA in Thermotoga neapolitana. Primary structure of LexA reveals phylogenetic relevance.

The chromosomal region of Thermotoga neapolitana surrounding the gene lexA (4283 bp) was sequenced. In addition to the topoisomerase gene top2A it contained five open reading frames. A part of the cloned region showed high sequence homology with a previously published sequence of Th.

Drainage systems in thyroid surgery: a randomised trial of passive and suction drainage.

Objective: To investigate the effectiveness of high-vacuum and passive drainage systems after elective thyroid resection.

Design: Prospective randomised clinical study and multicentre postal survey.

Setting: Military hospital, Germany.

Val 70, Phe 72 and the last seven amino acid residues of C-terminal are essential to the function of norepinephrine transporter.

The norepinephrine transporter(NET) is a member of the Na+/Cl- dependent neurotransmitter transporter family and constitutes the target of several clinically important antidepressants. To delineate the critical amino acid residues and the function of C-terminal in regulating transport activity of NET, here we constructed two site mutants (V70F, F72V; V70I, F72V) and one C-terminal truncated mutant (delta 611-617). The wild type and mutants of NET were expressed in Xenopus oocytes by injection of their cRNA.

[Odontogenic focus as the etiology of cerebral ischemia].

Recent studies have shown that acute infections, especially of the respiratory tract, are an important risk factor for cerebral ischemia. Additionally we know that chronic dental infections may be a risk for myocardial infarction and artherosclerosis. However, the connection between stroke and dental infections has hardly been examined so far.

Effect of mutation of glycosylation sites on the Na+ dependence of steady-state and transient currents generated by the neuronal GABA transporter.

The GABA (gamma-aminobutyric acid) transporter (GAT1) belongs to a superfamily of secondary active uptake systems for neurotransmitters that depend on the electrochemical gradients for Na+ and Cl-. In the GAT1, two Na+ ions and one Cl- ion are co-transported with one GABA molecule. Steady-state transport activity and transient charge movements during partial reactions of the transport cycle of the GAT1 of mouse brain expressed in Xenopus oocytes were investigated by two-electrode voltage clamp.