Sequence of the lacZ gene of Escherichia coli

The nucleotide sequence of the lacZ gene coding for beta-galactosidase (EC 3.2.1.23) in Escherichia coli has been determined. Beta-Galactosidase is predicted to consist of 1023 residues, resulting in a protein with a mol. wt. of 116 353 per subunit. The protein sequence originally determined by Fowler and Zabin was shown to be essentially correct and in an Appendix these authors comment on the discrepancies.

pUR222, a vector for cloning and rapid chemical sequencing of DNA

A multipurpose plasmid, pUR222, was constructed. It contains six unique cloning sites (PstI, SalI, AccI, HindII, BamHI and EcoRI) in a small region of its lac Z-gene part. Insertion of foreign DNA into the plasmid can be easily detected. Bacteria harbouring recombinant plasmids generally give rise to white colonies, while those containing only vector DNA form blue colonies on indicator plates. Plasmid DNA purified by a rapid method (Birnboim, H.C. and Doly, J. (1979) Nucl. Acids. Res. 7, 1513-1523) can be used for chemical sequencing of the cloned insert DNA. Labeled fragments need not be isolated after cutting with the proper restriction enzymes and are treated directly according to the sequencing protocol of Maxam and Gilbert.

Effect of ionic strength on initial interactions of Escherichia coli with surfaces, studied on-line by a novel quartz crystal microbalance technique

A novel quartz crystal microbalance (QCM) technique was used to study the adhesion of nonfimbriated and fimbriated Escherichia coli mutant strains to hydrophilic and hydrophobic surfaces at different ionic strengths. This technique enabled us to measure both frequency shifts (Deltaf), i.e., the increase in mass on the surface, and dissipation shifts (DeltaD), i.e., the viscoelastic energy losses on the surface. Changes in the parameters measured by the extended QCM technique reflect the dynamic character of the adhesion process. We were able to show clear differences in the viscoelastic behavior of fimbriated and nonfimbriated cells attached to surfaces. The interactions between bacterial cells and quartz crystal surfaces at various ionic strengths followed different trends, depending on the cell surface structures in direct contact with the surface. While Deltaf and DeltaD per attached cell increased for nonfimbriated cells with increasing ionic strengths (particularly on hydrophobic surfaces), the adhesion of the fimbriated strain caused only low-level frequency and dissipation shifts on both kinds of surfaces at all ionic strengths tested. We propose that nonfimbriated cells may get better contact with increasing ionic strengths due to an increased area of contact between the cell and the surface, whereas fimbriated cells seem to have a flexible contact with the surface at all ionic strengths tested. The area of contact between fimbriated cells and the surface does not increase with increasing ionic strengths, but on hydrophobic surfaces each contact point seems to contribute relatively more to the total energy loss. Independent of ionic strength, attached cells undergo time-dependent interactions with the surface leading to increased contact area and viscoelastic losses per cell, which may be due to the establishment of a more intimate contact between the cell and the surface. Hence, the extended QCM technique provides new qualitative information about the direct contact of bacterial cells to surfaces and the adhesion mechanisms involved.

Adhesion of type 1-fimbriated Escherichia coli to abiotic surfaces leads to altered composition of outer membrane proteins

Phenotypic differences between planktonic bacteria and those attached to abiotic surfaces exist, but the mechanisms involved in the adhesion response of bacteria are not well understood. By the use of two-dimensional (2D) polyacrylamide gel electrophoresis, we have demonstrated that attachment of Escherichia coli to abiotic surfaces leads to alteration in the composition of outer membrane proteins. A major decrease in the abundance of resolved proteins was observed during adhesion of type 1-fimbriated E. coli strains, which was at least partly caused by proteolysis. Moreover, a study of fimbriated and nonfimbriated mutants revealed that these changes were due mainly to type 1 fimbria-mediated surface contact and that only a few changes occurred in the outer membranes of nonfimbriated mutant strains. Protein synthesis and proteolytic degradation were involved to different extents in adhesion of fimbriated and nonfimbriated cells. While protein synthesis appeared to affect adhesion of only the nonfimbriated strain, proteolytic activity mostly seemed to contribute to adhesion of the fimbriated strain. Using matrix-assisted laser desorption ionization-time of flight mass spectrometry, six of the proteins resolved by 2D analysis were identified as BtuB, EF-Tu, OmpA, OmpX, Slp, and TolC. While the first two proteins were unaffected by adhesion, the levels of the last four were moderately to strongly reduced. Based on the present results, it may be suggested that physical interactions between type 1 fimbriae and the surface are part of a surface-sensing mechanism in which protein turnover may contribute to the observed change in composition of outer membrane proteins. This change alters the surface characteristics of the cell envelope and may thus influence adhesion.

The Sheep Grimace Scale as an indicator of post-operative distress and pain in laboratory sheep

The EU Directive 2010/63/EU changed the requirements regarding the use of laboratory animals and raised important issues related to assessing the severity of all procedures undertaken on laboratory animals. However, quantifiable parameters to assess severity are rare, and improved assessment strategies need to be developed. Hence, a Sheep Grimace Scale (SGS) was herein established by observing and interpreting sheep facial expressions as a consequence of pain and distress following unilateral tibia osteotomy. The animals were clinically investigated and scored five days before surgery and at 1, 3, 7, 10, 14 and 17 days afterwards. Additionally, cortisol levels in the saliva of the sheep were determined at the respective time points. For the SGS, video recording was performed, and pictures of the sheep were randomized and scored by blinded observers. Osteotomy in sheep resulted in an increased clinical severity score from days 1 to 17 post-surgery and elevated salivary cortisol levels one day post-surgery. An analysis of facial expressions revealed a significantly increased SGS on the day of surgery until day 3 post-surgery; this elevated level was sustained until day 17. Clinical severity and SGS scores correlated positively with a Pearson´s correlation coefficient of 0.47. Further investigations regarding the applicability of the SGS revealed a high inter-observer reliability with an intraclass correlation coefficient of 0.92 and an accuracy of 68.2%. In conclusion, the SGS represents a valuable approach for severity assessment that may help support and refine a widely used welfare assessment for sheep during experimental procedures, thereby meeting legislation requirements and minimizing the occurrence of unrecognized distress in animal experimentation.

Volumetric modulated Arc therapy and conventional intensity-modulated radiotherapy for simultaneous maximal intraprostatic boost: a planning comparison study

AIMS

Volumetric modulated arc therapy (VMAT) is a novel extension of intensity-modulated radiotherapy (IMRT) where an optimised three-dimensional dose distribution may be delivered in a single gantry rotation. This optimisation algorithm is the predecessor to Varian's RapidArc. The aim of this study was to compare the ability of conventional static nine-field IMRT (cIMRT) and VMAT to boost as much of the clinical target volume (CTV) as possible to 88.8Gy without exceeding organ at risk (OAR) dose-volume constraints.

MATERIALS AND METHODS

Optimal cIMRT and VMAT radiotherapy plans were produced for 10 patients with localised prostate cancer using common planning objectives: (1) Treat >or=98% of the planning target volume (PTV) to >or=95% of the prescription dose (74Gy in 37 fractions); (2) keep OAR doses within predefined limits; (3) treat as much of prostate CTV (minus urethra) as possible to >or=120% of prescription dose (=88.8Gy); (4) keep within maximum dose limits in and out of target volumes; (5) conformality index (volume of 95% isodose/volume of PTV)<or=1.2.

RESULTS

VMAT and cIMRT boosted an average of 68.8 and 63.5% of the CTV to >or=120% of the prescription dose (P=0.002). All dose constraints were kept within predefined limits. VMAT and cIMRT required an average of 949 and 1819 monitor units and 3.7 and 9.6min, respectively, to deliver a single radiation fraction.

CONCLUSIONS

VMAT is able to boost more of the CTV to >or=120% than cIMRT without contravening OAR dose constraints, and uses 48% fewer monitor units. Treatment times were 61% less than with cIMRT.

Growth of Vibrio anguillarum in Salmon Intestinal Mucus

The physiological changes of Vibrio anguillarum in response to growth in salmon intestinal mucus were investigated. Growth, survival, and changes in protein expression during growth in media supplemented with mucus were compared to growth and starvation in the identical media without mucus. V. anguillarum exhibited a rapid decline in CFU following growth in mucus as the sole carbon source. No such decline was observed in Luria broth with a 2% NaCl concentration, in glucose-minimal broth (3M), or during starvation in a carbon-, nitrogen-, and phosphorus-free salt solution (NSS). The changes in protein expression during growth in mucus were examined by labeling cells with [(sup35)S]methionine and analyzing the labeled proteins by one- and two-dimensional gel electrophoresis and autoradiography. Comparison of [(sup35)S]methionine-labeled proteins from mucus-grown cells with 3M-grown cells and NSS-starved cells revealed four de novo mucus-inducible proteins (Mips). These Mips were localized in the membrane fraction of V. anguillarum. Additionally, at least one other membrane protein was found to have increased expression in response to growth in mucus.

Improved purification of cathepsin B1 and cathepsin B2

An improved purification of the cathepsins B1 and B2 from bovine spleen is described. In addition to the formerly used procedure, chromatography with DEAE-Sephadex or -cellulose and mercurated agarose is used. Both enzymes are obtained in an electrophoretically pure form but consist of two or more isoenzymes. The isolation procedure leads to enzymes with high specific activities in satisfactory yields. Cathepsin B1 is frequently accompanied by small amounts of an arylamidase-like enzyme that hydrolyzes leucine p-nitroanilide. However, very probably, cathepsin B1 itself has a low activity toward this substrate too. Cathepsin B2 has a comparatively high activity with its characteristic though not specific substrate, alpha-N-benzoyl-L-arginineamide, whereas the activity toward haemoglobin is far lower. Both enzymes possess an essential SH group and require EDTA and a mercaptane for full activity, but their stability is markedly impaired by storage at higher thiol concentrations; Some other properties of the enzymes are also discussed.

The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes

The near-Earth carbonaceous asteroid 162173 Ryugu is thought to have been produced from a parent body that contained water ice and organic molecules. The Hayabusa2 spacecraft has obtained global multicolor images of Ryugu. Geomorphological features present include a circum-equatorial ridge, east-west dichotomy, high boulder abundances across the entire surface, and impact craters. Age estimates from the craters indicate a resurfacing age of [Formula: see text] years for the top 1-meter layer. Ryugu is among the darkest known bodies in the Solar System. The high abundance and spectral properties of boulders are consistent with moderately dehydrated materials, analogous to thermally metamorphosed meteorites found on Earth. The general uniformity in color across Ryugu's surface supports partial dehydration due to internal heating of the asteroid's parent body.

Ageing and changes in protein conformation in the human lens: a Raman microspectroscopic study

Using confocal Raman microspectroscopy with laser light of 660 nm the secondary and tertiary conformation of crystallins was studied in human lenses of varying age (20-75 years). Differences in cortical and nuclear proteins in individual lenses and among lenses of different age and differences between small equatorial opacities and adjacent clear sites were analysed using a difference spectrum approach. Intensity calibration allows assessment of local variations in protein content. The main findings and conclusions are as follows. (1) Irrespective of the age of the lens nuclear proteins proved to contain more aromatic amino acids, i.e. tryptophan, tyrosine and phenylalanine. This change most probably reflects differences in crystallin composition between nucleus and cortex as described in biochemical studies. (2) Changes in the amide bands indicate a more pronounced beta-sheet conformation of the nuclear proteins. Taking into account available biochemical evidence this most probably reflects a true post-translational change in the secondary conformation of the crystallins. (3) Cortical proteins in 'old' and 'young' lenses are largely identical indicating that ageing is not accompanied by gross alterations in the transcription/translation of the crystallin genes. (4) 'Old' and 'young' nuclear proteins deviate with respect to the amount of aromatic amino acids, being more abundant in 'young' nuclear proteins. (5) Proteins in small early opacities do not exhibit alterations in conformation. (6) A pronounced peak in the difference spectra in the region 1425-1435 cm-1 for nuclear proteins especially when compared with equatorial cortical proteins may be considered as evidence for the advanced photooxidation of tryptophan and/or deamidation of asparagine from superficial to deep regions of the lens.

Electroencephalographic power spectrum analysis as a monitor of anesthetic depth in horses

Electroencephalographic (EEG) power spectrum analysis was performed in 18 conscious, adult horses for evaluation as control values for EEG data obtained during anesthesia. Computer-processed total amplitudes for the frequency range 0 to 32 Hz were mainly between 400 and 600 microV, with 80% spectral edge frequency between 16.6 and 32.5 Hz. The highest electrical activity was in the delta band (41.3 +/- 4.4% of total amplitude); there was a less pronounced activity in the beta (34.2 +/- 5.2%), theta (13.6 +/- 1.5%), and alpha (10.0 +/- 1.0%) bands. The applicability of EEG power spectrum analysis as a guide to depth of anesthesia was evaluated in four horses by comparing simultaneously recorded EEG data and clinical signs of anesthesia. Global changes in cerebrocortical electrical activity were detected with a single, monopolar (left frontoatlanto-occipital) EEG lead. Increasing depth of halothane anesthesia was accompanied by a pronounced shift in EEG activity from beta to theta and delta frequency bands, a decrease in 80% spectral edge frequency from 21.5 +/- 2.4 Hz to 12.6 +/- 2.2 Hz, a reduction in the beta/delta ratio of fractional amplitudes from 2.37 +/- 0.84 to 0.49 +/- 0.04, and a slight inconsistent increase in total amplitude from 96.1 +/- 37.3 microV to 185.5 +/- 53 microV. These results show that changes in the clinical signs of anesthetic depth in horses can be described numerically by use of EEG power spectrum analysis.

Biochemical aspects of flight and flightlessness in Gryllus: flight fuels, enzyme activities and electrophoretic profiles of flight muscles from flight-capable and flightless morphs

Female Gryllus assimilis subjected to 4.5-7.7h continuous tethered flight had significantly lower amounts of total lipid, triglyceride and total soluble carbohydrate compared with unflown controls. A much greater amount of total lipid (6.3mg) was used during flight compared with carbohydrate (0.14mg). Flown individuals also had substantially reduced amounts of injected, radiolabeled [(14)C]-oleic acid. Activities of lipid, carbohydrate and amino acid catabolizing enzymes in flight muscles of G. assimilis and its wing-polymorphic congener, G. firmus, were very similar to activities in insects which primarily utilize lipid to power flight. By contrast, enzyme activities were very different from those in insects which primarily or exclusively use carbohydrate or proline as a flight fuel. These results strongly implicate lipid as the major flight fuel in Gryllus. Previous studies have shown that lipid levels are higher in flight-capable (long-winged) G. firmus that have small ovaries compared with flightless (short-winged) females that have large ovaries. Results of the present and previous studies collectively indicate that elevated lipid in long-winged G. firmus represents an energetic cost of flight capability which reduces (trade-offs with) reproduction in Gryllus. In G. firmus, mass-specific activities of nearly all enzymes were considerably reduced in underdeveloped, and to a lesser degree in histolyzed muscle, compared with fully-developed flight muscle. An important exception was alanine aminotransferase, whose activity was the highest in histolyzed muscle, and which may be involved in the catabolism of amino acids derived from muscle degradation. Despite the dramatic differences in enzyme activity, electrophoretic profiles of soluble flight-muscle proteins differed only subtly between fully-developed and underdeveloped or histolyzed flight muscles.

Local variations in protein structure in the human eye lens: a Raman microspectroscopic study

Confocal Raman microspectroscopy was used to monitor local and age-related changes in protein conformation in human eye lenses. In clear human lenses of varying age (range 17-80 years) spectra were recorded along the visual axis, using laser light of 660 nm wavelength. The Raman vibrations in the 650-1750 cm-1 spectral region were analyzed. Difference spectra between central core and different positions along the visual axis were calculated after calibration for protein content using the I(1450) cm-1 CH2/CH3 vibration peak. Tryptophan content was quantified using the peak at 760 cm-1 calibrated for protein. Changes in the 'exposed' vs. 'buried' position of tryptophan were analyzed using the peak heights at I(880) and I(760) cm-1. The difference spectra revealed an excess of tryptophan, tyrosine, phenylalanine, beta-sheet conformation and molecules or molecular groups responsible for a 1425 cm-1 peak in the core region in all lenses investigated. The excess peaks disappeared at about 0.6-0.9 mm below the surface. The tryptophan content increased from superficial to deep layers, levelling off between 0.4-0.8 mm below the surface. Upon aging, the tryptophan content increases in the core not in the cortex. No changes in the 'exposed' vs. 'buried' position of tryptophan were observed. Changes in tryptophan and tyrosine probably reflect the maturational shift from cortex to core in the relative content of alpha, beta and gamma crystallines. The age-related increase in tryptophan in the core may reflect the preferential breakdown by endo- and exopeptidases of alpha-crystallins damaged upon aging. The increase in beta-sheet conformation may indicate a post-translational shift in secondary conformation upon aging. These changes in protein conformation are largely completed in a small superficial zone, i.e., in the early life span of the crystallins.

Model for experimental revascularized laryngeal allotransplantation

BACKGROUND

Although a human laryngeal transplant has been undertaken successfully, important questions remain that require a suitable animal model.

METHODS

A pig model for allotransplantation has been developed. Organ perfusion was studied in nine animals before four transplants were performed in congenic (unrecovered) animals and eight in unmatched (recovered) animals. Larynges were regularly examined endoscopically until death at 14 days. Immunosuppression included the use of tacrolimus. Revascularization was achieved by anastomosing the donor right cervical vascular tree to the recipient common carotid. In recovered animals, four allografts were placed orthotopically and four heterotopically.

RESULTS

The pig larynx was perfused adequately via the right cervical vascular tree and congenic grafts were well tolerated. Of eight allografts, seven were well tolerated and remained healthy for the duration of the study (14 days). One allograft became infected between days 4 and 7 after operation. Median operating time was 6 h, with a median cold ischaemia time of 3 h.

CONCLUSION

Revascularized allotransplants of the larynx can be undertaken reliably in pigs and this provides a preclinical model for studies of laryngeal transplantation.

Rasagiline improves polysomnographic sleep parameters in patients with Parkinson's disease: a double-blind, baseline-controlled trial

BACKGROUND AND PURPOSE

The aim was to study the effects of rasagiline on sleep quality in patients with Parkinson's disease (PD) with sleep disturbances. Sleep disorders are common in PD. Rasagiline is widely used in patients with PD, but double-blind polysomnographic trials on its effects on sleep disturbances are missing.

METHODS

This was a single-center, double-blind, baseline-controlled investigator-initiated clinical trial of rasagiline (1 mg/day) over 8 weeks in patients with PD with sleep disturbances. Blinding was achieved by running a strategic matched placebo parallel group. Co-primary outcome measures were the changes between baseline and end of the treatment period in sleep maintenance/efficiency as assessed by polysomnography and the Parkinson's Disease Sleep Scale Version 2 (PDSS-2) score.

RESULTS

A total of 20 of 30 patients were randomized to rasagiline (mean ± SD age, 69.9 ± 6.9 years; 10 male; Hoehn-Yahr stage, 1.9 ± 0.8). Compared with baseline, sleep maintenance was significantly increased at the end of the treatment period (relative change normalized to baseline, +16.3 ± 27.9%; P = 0.024, paired two-sided t-test) and a positive trend for sleep efficiency was detected (+12.1 ± 28.6%; P = 0.097). Treatment with rasagiline led to significantly decreased wake time after sleep onset, number of arousals, percentage of light sleep and improved daytime sleepiness as measured by the Epworth Sleepiness Scale. We did not observe changes in the co-primary endpoint PDSS-2 score, and no correlations of polysomnographic sleep parameters or PDSS-2 score with motor function (Unified Parkinson's Disease Rating Scale motor score). Rasagiline was well tolerated with no unexpected adverse events.

CONCLUSIONS

In patients with PD with sleep disturbances, rasagiline showed beneficial effects on sleep quality as measured by polysomnography. These effects were probably not related to motor improvement or translated into improved overall sleep quality perception by patients.

Frame slippage verification in stereotactic radiosurgery

PURPOSE

To develop a method for detecting frame slippage in stereotactic radiosurgery by interactively matching in three dimensions Digitally Reconstructed Radiographs (DRRs) to portal images.

METHODS AND MATERIALS

DRRs are superimposed over orthogonal edge-detected portal image pairs obtained prior to treatment. By interactively manipulating the CT data in three dimensions (rotations and translations) new DRRs are generated and overlaid with the orthogonal portal images. This method of matching is able to account for ambiguities due to rotations and translations outside of the imaging plane. The matching procedure is performed with anatomical structures, and is used in tandem with a fiducial marker array attached to the stereotactic frame. The method is evaluated using portal images simulated from patient CT data and then tested using a radiographic head phantom.

RESULTS

For simulation tests a mean radial alignment error of 0.82 mm was obtained with the 3D matching method compared to a mean error of 3.52 mm when using conventional matching techniques. For the head phantom tests the mean alignment displacement error for each of the stereotactic coordinates was found to be delta(x) = 0.95 mm, delta(y) = 1.06 mm, delta(z) = 0.99 mm, with a mean error radial of 1.94 mm (SD = 0.61 mm).

CONCLUSION

Results indicate that the accuracy of the system is appropriate for stereotactic radiosurgery, and is therefore an effective tool for verification of frame slippage.

Conditional transformation of rat embryo fibroblast cells by a cyclin D1-cdk4 fusion gene

Cyclin D1 gene overexpression is a frequent event in a number of human cancers. These observations have led to the suggestion that cyclin D1 alterations might play a role in the etiology of cancer. This possibility is supported by the finding that transfection of mammalian cells with cyclin D1 can accelerate progression through the G1 phase of the cell cycle. Moreover, cyclin D1 can function as an oncogene by cooperating with activated Ha-ras to transform primary rat embryo fibroblasts (REFs). In addition, cyclin D1 transgenics develop hyperplasia and neoplasia of the thymus and mammary gland. We have constructed a novel fusion gene consisting of full-length human cyclin D1 and cdk4 genes. This fusion gene was expressed in insect cells and the fusion protein was shown to be enzymatically active. The fusion gene was expressed in mammalian cells under the control of tet-repressor. This fusion gene immortalized primary REFs, and cooperated with activated Ha-ras to transform primary REFs, in terms of anchorage-independent growth in vitro and formation of tumors in vivo. Utilizing a tet-regulated gene expression system, we have shown that proliferation of stably transfected primary REFs in vitro and in vivo is dependent on the continued expression of the cyclin D1-cdk4 fusion gene. These cell lines could be useful in the discovery of novel cancer therapeutics to modulate cyclin D1.cdk4 activity.

Construction and characterization of a one-plasmid system for the controlled expression of genes in mammalian cells by tetracycline

The two-plasmid system of Gossen and Bujard [Gossen and Bujard (1992) Proc. Natl. Acad. Sci. USA 89, 5547-5551] to express mammalian genes in a tetracycline-repressed fashion was combined into a single-plasmid system. Two variants of this single-plasmid system that differ in the multiple cloning site (MCS) region are described. These vectors were used to stably transfect raf kinase domain into the normal rat kidney epithelial cell line (NRKE) to obtain a conditionally transformed cell line. These vectors were also used to stably transfect wild-type and mutant human p53 into the human osteosarcoma cell line, SAOS-2. Tetracycline repressed gene expression in both cell lines; about 12-fold in NRKE and about 80-fold in SAOS-2 cell line.