Identification of antibacterial peptides from endophytic microbiome.

Endophytes, microorganisms living inside plant tissues, are promising producers of lead compounds for the pharmaceutical industry. However, the majority of endophytes are unculturable and therefore inaccessible for functional studies. To evaluate genetic resources of endophytes, we analyzed the biodiversity of fungal microbiome of black crowberry (Empetrum nigrum L.) by next-generation sequencing and found that it consists mainly of unknown taxa. We then separated the host and the endophyte genomes and constructed a fosmid expression library from the endophytic DNA. This library was screened for antibacterial activity against Staphylococcus aureus. A unique antibacterial clone was selected for further analysis, and a gene En-AP1 was identified with no similarity to known sequences. The expressed, folded protein En-AP1 was not active against S. aureus, while tryptic digests exhibited antimicrobial activity. Seven out of twelve synthesized peptides, predicted antibacterial in silico, exhibited in vitro activity towards both S. aureus and Escherichia coli. We propose that the En-AP1 protein is degraded in the library host E. coli and antimicrobial fragments are released from the cell, explaining the in vitro antibacterial activity of the clone. This is the first report of a novel gene expressed in vitro derived from an endophytic microbiome, demonstrating the potential of finding novel genes and compounds from unculturable endophytes.

Behavior of CAD/CAM ceramic veneers under stress: A 3D holographic study.

OBJECTIVES: Ceramic veneers restorations may undergo damages, such as cracks, fractures, or debonding. Full-field measurements must be carried out in order to visualize and analyze the strain fields. This paper demonstrates that digital holography permits to investigate the mechanical behavior under stress of a natural incisor and a natural incisor reconstructed with CAD/CAM ceramic veneer. METHODS: The facial surface of a maxillary central incisor is prepared to receive a monolithic ceramic reconstruction manufactured using a chairside computer-aided design and computer aided manufacturing (CAD/CAM) system (Cerec AC® system, Sirona Dental System®, Bensheim, Germany). One incisor is kept intact for comparison. The samples are sectioned longitudinally to obtain a planar observation of the region of interest. A mechanical indentation head and digital holographic set-ups permit a full-field, contact-less and single-shot measurement of the three-dimensional displacement fields at the surface of the tooth sample when subjected to load. Stain fields are then estimated and comparison of the results between two samples can be carried out. RESULTS: 3D displacement, fields and strain fields are measured and highlight the behavior of the region of interest in three directions of space for the ceramic veneer and the natural incisor. The strain maps reveal the local behavior, especially the concentration or the sudden change in strain. The transition zones are clearly observed, particularly for the veneered sample. CONCLUSION: Digital holography highlights the localization of stress concentration zones in regions of interest and yields comparative analysis between samples with different tooth preparations. SIGNIFICANCE: holography permits to visualize and compare the mechanical response of the ceramic veneer and natural tooth. This helps choosing the mechanical properties of the bonding interface.

Mechanical behavior of CAD/CAM occlusal ceramic reconstruction assessed by digital color holography.

OBJECTIVES: CAD/CAM ceramic occlusal veneers are increasingly used as therapeutic options. However, little is known about their mechanical behavior under stress, as the response of the prepared tooth that supports it. The aim of this article is to use for the first time 3D color holography to evaluate the behavior of a molar occlusal veneer under stress and the response of the prepared tooth. METHODS: The occlusal surface of a lower molar is prepared to receive a specific monolithic ceramic reconstruction manufactured with a chairside CAD/CAM system. Longitudinally cut samples are used to get a planar object observation and to "look inside" the tooth. A digital holographic set-up permits to obtain the contact-less and one-shot measurement of the three-dimensional displacement field at the surface of the tooth sample; stain fields are evaluated with low noise-sensitive computation. RESULTS: Figures show the strain fields with micro-strain units and highlight the behavior of the ROI (region of interest) in the three directions of space. The ROI are: the ceramic, the glue junction, the dentin enamel junction, dentin and enamel. The results show an excellent behavior of the restored tooth without areas of excessive stress concentrations, but also a significant involvement of the dentin enamel junction. SIGNIFICANCE: The ceramic occlusal veneer seems to behave in accordance with the biomechanical concepts ensuring the longevity of the reconstituted tooth. 3D holography is a highly recommended method for studying dental biomechanics.

Real time mathematical analysis of instantaneous respiratory signals at the bedside by a multiprocessor system (PAMS).

The authors address the following problems: How to turn a mass spectrometer, or a set of individual gas sensors, into a real and useful medical instrument? In other words, how to transform the instantaneous gas composition signals into meaningful physiological variables? The parameters that can be computed breath by breath from the real time processing of gas concentration signals, combined with flow and pressure signals at the mouth are first described. Particularly, we point out the theoretical and practical importance of alveolo-capillary gas exchange parameters, as opposed to gas exchange parameters estimated at the mouth level: A-c exchange parameters are a more sensitive and more specific indicator of any physiological change and they are less sensitive to breath by breath fluctuations of ventilation. We discuss the clinical usefulness of breath by breath computations, as a more sensitive way to monitor the patient as well as the anesthesia circuit, and to generate all the information required for on line analysis of functional tests. We describe a system for the real time processing of the respiratory signals. Based on three microprocessors it takes over the calibration, the offset correction of each signal ... It also corrects for the dynamics of each sensor and resynchronizes all the signals. It computes breath by breath more than 50 physiological variables that can be either recorded analogically, either printed, either acquired by a general monitoring system of the patient, which then combines respiratory data with other physiological. therapeutical and medical data from the patient.

Turning the mass-spectrometer into an easy to handle clinical instrument for routine multipatient surveillance of respiratory and anesthetic gases during anesthesia.

Although most authors use it as the reference instrument for respiratory gases measurement, the use of mass-spectrometer in clinical routine in ICU and in anesthesia remains quite limited. We developed a fully automatically controlled system, carrying on a twinned goal: The ACS-2000 (Automatic Calibration System) turns the Airspec MGA-2000 mass-spectrometer into a true clinical instrument, as easy to use as any routine monitoring instrument, and lets the clinician and the anesthetist benefit from its uncomparable metrological performances. PAMS-M, multibed monitoring system, shares the mass-spectrometer time among 4 to 8 rooms, providing each anesthetist with full composition of inspired and end tidal gases composition, trend evolution of those data, as with the display of capnogram. Each room is equipped with an IBM PC compatible intelligent terminal, abling the user to select the nature of the displayed information and enter into an easy menu driven dialog with the system. As a subproduct, the informatic infrastructure on which the system is based allowed, beyond the standard monitoring function, to set the bases of a computerized patient's anesthesia or respiratory monitoring report.

Cellulases from two Penicillium sp. strains isolated from subtropical forest soil: production and characterization.

AIMS: To isolate new fungal strains from subtropical soils and to identify those that produce high cellulase activity. To select microbial strains producing thermostable cellulases with potential application in industry. METHODS AND RESULTS: The new strains Penicillium sp. CR-316 and Penicillium sp. CR-313 have been identified and selected because they secreted a high level of cellulase in media supplemented with rice straw. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis, isoelectric focussing and zymography showed that the studied strains secreted multiple enzymes that hydrolyse cellulose. Cellulase activity of Penicillium sp. CR-316, the strain showing higher production, was analysed. Optimum temperature and pH of carboxymethyl cellulase activity were 65 degrees C and pH 4.5, respectively. Activity remained stable after incubation at 60 degrees C and pH 4.5 for 3 h. CONCLUSIONS: Fungal strains that secrete high levels of cellulase activity have been characterized and selected from soil. The isolated strains have complex sets of enzymes for cellulose degradation. Crude cellulase produced by Penicillium sp. CR-316 showed activity and stability at high temperature. SIGNIFICANCE AND IMPACT OF THE STUDY: Two fungal strains with biotechnological potential have been isolated. The strains secrete high levels of cellulase, and one of them, Penicillium sp. CR-316, produces a thermostable cellulase, that makes it a good candidate for industrial applications.

The first experience of a dedicated biomedical education unit at the university of franche-comté.

Biomedical activity is rapidly expanding. Actually, the demand for hi-tech technologies in health is in constant increase. At the Franche-Comté High Institute of Engineers (ISIFC) an engineer can acquire the knowledge and skills to carry out various tasks in biomedical engineering field including academic research, in-hospital devices maintenance or industrial development. The main advantage of the ISIFC is that it offers an exceptional multidisciplinary programme thank to close cooperation between Besançon University Hospital professionals and Engineering Sciences professors and researchers. As a result, the graduates obtain real experience in the both fields. The majority of the ISIFC engineers are employed by firms producing and/or commercializing health-oriented materials and equipments such as Alcis, Arthesis, Aventis Pasteur, Biomérieux, Imasonic, Medos, Statice Santé, Sophysa, Symbios, Praxim, Protheos, Tornier, Zimmer etc.

Systematic errors of phase-shifting speckle interferometry.

A theoretical and numerical investigation of the systematic phase errors in phase-shifting speckle interferometry is presented. The theoretical investigation analyzes the behavior of some systematic error induced by intensity variations in two cases of data-computing techniques. The first case deals with the technique in which the phase change is computed, unwrapped, and then linearly filtered; the second case deals with the technique in which the data are linearly filtered before the arctangent calculation and then unwrapped. With the first filtering technique it is shown that it is preferable when the phase change is of relatively low spatial frequency, leading to a particularly accurate method. With the second case it is demonstrated that an important parameter of speckle interferometry is the modulation factor of the interference frame that induces phase errors when the data are filtered before the arctangent calculation. We show that this technique is better than the first when the phase change is composed of high-spatial-frequency variations. The theoretical investigation of the two techniques is compared with numerical simulations, considering the frequency characteristics of the phase change, and this shows a good match between theory and simulations.

On the rise time of ultrafast surface displacement of laser-irradiated surface

It is demonstrated that acoustic attenuation does not influence the rise time of transient laser-induced displacement of a surface.

Development of a biosensor for on-line detection of tributyltin with a recombinant bioluminescent Escherichia coli strain.

A biosensor was developed for the detection of tributyltin (TBT), using a bioluminescent recombinant Escherichia coli:: luxAB strain. Dedicated devices allowed the on-line measurement of bioluminescence, pH and dissolved oxygen values and the feed-back regulation of temperature. Bacterial physiology was monitored by the measurement of the cellular density, respiratory activity and the intracellular level of ATP, glucose and acetate levels. Our results showed that a synthetic glucose medium gave a better TBT detection limit than LB medium (respectively 0.02 micro M and 1.5 micro M TBT). High growth and dilution rates ( D=0.9 h(-1)) allowed maximum light emission from the bacterium. Moreover, simple atmospheric air bubbling was sufficient to provide oxygen for growth and the bioluminescence reaction. Real-time monitoring of bioluminescence after TBT induction occurred with continuous addition of decanal up to 300 micro M, which was not toxic throughout a 7-day experiment. The design of our biosensor and the optimization of the main parameters that influence microbial activity led to the capacity for the detection of TBT.