2022
Report
Open Access
SI-Lab annual research report 2021
Righi M., Leone G. R., Carboni A., Caudai C., Colantonio S., Kuruoglu E. E., Leporini B., Magrini M., Paradisi P., Pascali M. A., Pieri G., Reggiannini M., Salerno E., Scozzari A., Tonazzini A., Fusco G., Galesi G., Martinelli M., Pardini F., Tampucci M., Berti A., Bruno A., Buongiorno R., Carloni G., Conti F., Germanese D., Ignesti G., Matarese F., Omrani A., Pachetti E., Papini O., Benassi A., Bertini G., Coltelli P., Tarabella L., Straface S., Salvetti O., Moroni D.
The Signal & Images Laboratory is an interdisciplinary research group in computer vision, signal analysis, intelligent vision systems and multimedia data understanding. It is part of the Institute of Information Science and Technologies (ISTI) of the National Research Council of Italy (CNR). This report accounts for the research activities of the Signal and Images Laboratory of the Institute of Information Science and Technologies during the year 2021.Source: ISTI Annual reports, 2022
DOI: 10.32079/isti-ar-2022/003
Metrics:
Righi M., Leone G. R., Carboni A., Caudai C., Colantonio S., Kuruoglu E. E., Leporini B., Magrini M., Paradisi P., Pascali M. A., Pieri G., Reggiannini M., Salerno E., Scozzari A., Tonazzini A., Fusco G., Galesi G., Martinelli M., Pardini F., Tampucci M., Berti A., Bruno A., Buongiorno R., Carloni G., Conti F., Germanese D., Ignesti G., Matarese F., Omrani A., Pachetti E., Papini O., Benassi A., Bertini G., Coltelli P., Tarabella L., Straface S., Salvetti O., Moroni D.
The Signal & Images Laboratory is an interdisciplinary research group in computer vision, signal analysis, intelligent vision systems and multimedia data understanding. It is part of the Institute of Information Science and Technologies (ISTI) of the National Research Council of Italy (CNR). This report accounts for the research activities of the Signal and Images Laboratory of the Institute of Information Science and Technologies during the year 2021.Source: ISTI Annual reports, 2022
DOI: 10.32079/isti-ar-2022/003
Metrics:
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ISTI Repository 
| CNR ExploRA
2021
Report
Open Access
SI-Lab Annual Research Report 2020
Leone G. R., Righi M., Carboni A., Caudai C., Colantonio S., Kuruoglu E. E., Leporini B., Magrini M., Paradisi P., Pascali M. A., Pieri G., Reggiannini M., Salerno E., Scozzari A., Tonazzini A., Fusco G., Galesi G., Martinelli M., Pardini F., Tampucci M., Buongiorno R., Bruno A., Germanese D., Matarese F., Coscetti S., Coltelli P., Jalil B., Benassi A., Bertini G., Salvetti O., Moroni D.
The Signal & Images Laboratory (http://si.isti.cnr.it/) is an interdisciplinary research group in computer vision, signal analysis, smart vision systems and multimedia data understanding. It is part of the Institute for Information Science and Technologies of the National Research Council of Italy. This report accounts for the research activities of the Signal and Images Laboratory of the Institute of Information Science and Technologies during the year 2020.Source: ISTI Annual Report, ISTI-2021-AR/001, pp.1–38, 2021
DOI: 10.32079/isti-ar-2021/001
Metrics:
Leone G. R., Righi M., Carboni A., Caudai C., Colantonio S., Kuruoglu E. E., Leporini B., Magrini M., Paradisi P., Pascali M. A., Pieri G., Reggiannini M., Salerno E., Scozzari A., Tonazzini A., Fusco G., Galesi G., Martinelli M., Pardini F., Tampucci M., Buongiorno R., Bruno A., Germanese D., Matarese F., Coscetti S., Coltelli P., Jalil B., Benassi A., Bertini G., Salvetti O., Moroni D.
The Signal & Images Laboratory (http://si.isti.cnr.it/) is an interdisciplinary research group in computer vision, signal analysis, smart vision systems and multimedia data understanding. It is part of the Institute for Information Science and Technologies of the National Research Council of Italy. This report accounts for the research activities of the Signal and Images Laboratory of the Institute of Information Science and Technologies during the year 2020.Source: ISTI Annual Report, ISTI-2021-AR/001, pp.1–38, 2021
DOI: 10.32079/isti-ar-2021/001
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ISTI Repository | CNR ExploRA
2020
Journal article
Open Access
Unveiling the secrets of Escher's lithographs
Coltelli P., Barsanti L., Gualtieri P.
An impossible structure gives us the impression of looking at a three-dimensional object, even though this object cannot exist, since it possesses parts that are spatially non-connectable, and are characterized by misleading geometrical properties not instantly evident. Therefore, impossible artworks appeal to our intellect and challenge our perceptive capacities. We analyzed lithographs containing impossible structures (e.g., the Necker cube), created by the famous Dutch painter Maurits Cornelis Escher (1898-1972), and used one of them (The Belvedere, 1958) to unveil the artist's hidden secrets by means of a discrete model of the human retina based on a non-uniform distribution of receptive fields. We demonstrated that the ability of Escher in composing his lithographs by connecting spatial coherent details into an impossible whole lies in drawing these incoherent fragments just outside the zone in which 3D coherence can be perceived during a single fixation pause. The main aspects of our paper from the point of view of image processing and image understanding are the following: (1) the peculiar and original digital filter to process the image, which simulates the human vision process, by producing a space-variant sampling of the image; (2) the software for the filter, which is homemade and created for our purposes. The filtered images resulting from the processing are used to understand impossible figures. As an example, we demonstrate how the impossible figures hidden in Escher's paintings can be understood.Source: JOURNAL OF IMAGING 6 (2020). doi:10.3390/jimaging6020005
DOI: 10.3390/jimaging6020005
Metrics:
Coltelli P., Barsanti L., Gualtieri P.
An impossible structure gives us the impression of looking at a three-dimensional object, even though this object cannot exist, since it possesses parts that are spatially non-connectable, and are characterized by misleading geometrical properties not instantly evident. Therefore, impossible artworks appeal to our intellect and challenge our perceptive capacities. We analyzed lithographs containing impossible structures (e.g., the Necker cube), created by the famous Dutch painter Maurits Cornelis Escher (1898-1972), and used one of them (The Belvedere, 1958) to unveil the artist's hidden secrets by means of a discrete model of the human retina based on a non-uniform distribution of receptive fields. We demonstrated that the ability of Escher in composing his lithographs by connecting spatial coherent details into an impossible whole lies in drawing these incoherent fragments just outside the zone in which 3D coherence can be perceived during a single fixation pause. The main aspects of our paper from the point of view of image processing and image understanding are the following: (1) the peculiar and original digital filter to process the image, which simulates the human vision process, by producing a space-variant sampling of the image; (2) the software for the filter, which is homemade and created for our purposes. The filtered images resulting from the processing are used to understand impossible figures. As an example, we demonstrate how the impossible figures hidden in Escher's paintings can be understood.Source: JOURNAL OF IMAGING 6 (2020). doi:10.3390/jimaging6020005
DOI: 10.3390/jimaging6020005
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Journal of Imaging | Journal of Imaging | ISTI Repository | DOAJ-Articles | Journal of Imaging | CNR ExploRA
2019
Journal article
Open Access
Paramylon treatment improves quality profile and drought resistance in Solanum lycopersicum L. cv. Micro-Tom
Barsanti L., Coltelli P., Gualtieri P.
Tomatoes, the most cultivated vegetables worldwide, require large amounts of water and are adversely affected by water stress. Solanum lycopersicum L., cv. Micro-Tom was used to assess the effects of beta-(1,3)-glucan (paramylon) purified from the microalga Euglena gracilis on drought resistance and fruit quality profile. Plants were grown in an aeroponic system under three cultivation conditions: optimal water regimen, water scarcity regimen, and water scarcity regimen coupled with a root treatment with paramylon. Eco-physiological, physicochemical and quality parameters were monitored and compared throughout the lifecycle of the plants. Drought stress caused only a transient effect on the eco-physiological parameters of paramylon-treated plants, whereas physicochemical and biochemical parameters underwent significant variations. In particular, the fruits of paramylon-treated plants reached the first ripening stage two weeks before untreated plants grown under the optimal water regime, while the fruits of stressed untreated plants did not ripe beyond category II. Moreover, antioxidant compounds (carotenoids, phenolic acid, and vitamins) of fruits from treated plants underwent a two-fold increase with respect to untreated plants, as well as soluble carbohydrates (glucose, fructose, and sucrose). These results show that paramylon increases plant resistance to drought and highly improves the quality profile of the fruits with respect to untreated plants grown under drought stress.Source: Agronomy (Basel) 9 (2019). doi:10.3390/agronomy9070394
DOI: 10.3390/agronomy9070394
Metrics:
Barsanti L., Coltelli P., Gualtieri P.
Tomatoes, the most cultivated vegetables worldwide, require large amounts of water and are adversely affected by water stress. Solanum lycopersicum L., cv. Micro-Tom was used to assess the effects of beta-(1,3)-glucan (paramylon) purified from the microalga Euglena gracilis on drought resistance and fruit quality profile. Plants were grown in an aeroponic system under three cultivation conditions: optimal water regimen, water scarcity regimen, and water scarcity regimen coupled with a root treatment with paramylon. Eco-physiological, physicochemical and quality parameters were monitored and compared throughout the lifecycle of the plants. Drought stress caused only a transient effect on the eco-physiological parameters of paramylon-treated plants, whereas physicochemical and biochemical parameters underwent significant variations. In particular, the fruits of paramylon-treated plants reached the first ripening stage two weeks before untreated plants grown under the optimal water regime, while the fruits of stressed untreated plants did not ripe beyond category II. Moreover, antioxidant compounds (carotenoids, phenolic acid, and vitamins) of fruits from treated plants underwent a two-fold increase with respect to untreated plants, as well as soluble carbohydrates (glucose, fructose, and sucrose). These results show that paramylon increases plant resistance to drought and highly improves the quality profile of the fruits with respect to untreated plants grown under drought stress.Source: Agronomy (Basel) 9 (2019). doi:10.3390/agronomy9070394
DOI: 10.3390/agronomy9070394
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Agronomy | ISTI Repository | Agronomy | Agronomy | CNR ExploRA
2017
Journal article
Open Access
Algae through the looking glass
Coltelli P., Barsanti L., Evangelista V., Gualtieri P.
Microalgae are one of the most suitable subjects for testing the potentiality of light microscopy and image analysis, because of the size of single cells, their endogenous chromaticity, and their metabolic and physiological characteristics. Microscope observations and image analysis can use microalgal cells from lab cultures or collected from water bodies as model to investigate metabolic processes, behavior/reaction of cells under chemical or photic stimuli, and dynamics of population in the natural environment in response to changing conditions. In this paper we will describe the original microscope we set up together with the image processing techniques we improved to deal with these topics. Our system detects and recognizes in-focus cells, extracts their features, measures cell concentration in multi-algal samples, reconstructs swimming cell tracks, monitors metabolic processes, and measure absorption and fluorescent spectra of subcellular compartments. It can be used as digital microscopy station for algal cell biology and behavioral studies, and field analysis applications.Source: Microscopy research and technique (Print) 80 (2017): 486–494. doi:10.1002/jemt.22820
DOI: 10.1002/jemt.22820
Metrics:
Coltelli P., Barsanti L., Evangelista V., Gualtieri P.
Microalgae are one of the most suitable subjects for testing the potentiality of light microscopy and image analysis, because of the size of single cells, their endogenous chromaticity, and their metabolic and physiological characteristics. Microscope observations and image analysis can use microalgal cells from lab cultures or collected from water bodies as model to investigate metabolic processes, behavior/reaction of cells under chemical or photic stimuli, and dynamics of population in the natural environment in response to changing conditions. In this paper we will describe the original microscope we set up together with the image processing techniques we improved to deal with these topics. Our system detects and recognizes in-focus cells, extracts their features, measures cell concentration in multi-algal samples, reconstructs swimming cell tracks, monitors metabolic processes, and measure absorption and fluorescent spectra of subcellular compartments. It can be used as digital microscopy station for algal cell biology and behavioral studies, and field analysis applications.Source: Microscopy research and technique (Print) 80 (2017): 486–494. doi:10.1002/jemt.22820
DOI: 10.1002/jemt.22820
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ISTI Repository | Microscopy Research and Technique 
| onlinelibrary.wiley.com | CNR ExploRA
2016
Journal article
Open Access
Swimming patterns of the quadriflagellate Tetraflagellochloris mauritanica (Chlamydomonadales, Chlorophyceae)
Barsanti L., Coltelli P., Evangelista V., Frassanito A. M., Gualtieri P.
Chlamydomonadales are elective subjects for the investigation of the problems related to locomotion and transport in biological fluid dynamics, whose resolution could enhance searching efficiency and assist in the avoidance of dangerous environments. In this paper, we elucidate the swimming behavior of Tetraflagellochloris mauritanica, a unicellular- multicellular alga belonging to the order Chlamydomonadales. This quadriflagellate alga has a complex swimming motion consisting of alternating swimming phases connected by in-place random reorientations and resting phases. It is capable of both forward and backward swimming, both being normal modes of swimming. The complex swimming behavior resembles the run-andtumble motion of peritrichous bacteria, with inplace reorientation taking the place of tumbles. In the forward swimming, T. mauritanica shows a very efficient flagellar beat, with undulatory retrograde waves that run along the flagella to their tip. In the backward swimming, the flagella show a nonstereotypical synchronization mode, with a pattern that does not fit any of the modes present in the other Chlamydomonadales so far investigatedSource: Journal of phycology 52 (2016): 209–218. doi:10.1111/jpy.12384
DOI: 10.1111/jpy.12384
Metrics:
Barsanti L., Coltelli P., Evangelista V., Frassanito A. M., Gualtieri P.
Chlamydomonadales are elective subjects for the investigation of the problems related to locomotion and transport in biological fluid dynamics, whose resolution could enhance searching efficiency and assist in the avoidance of dangerous environments. In this paper, we elucidate the swimming behavior of Tetraflagellochloris mauritanica, a unicellular- multicellular alga belonging to the order Chlamydomonadales. This quadriflagellate alga has a complex swimming motion consisting of alternating swimming phases connected by in-place random reorientations and resting phases. It is capable of both forward and backward swimming, both being normal modes of swimming. The complex swimming behavior resembles the run-andtumble motion of peritrichous bacteria, with inplace reorientation taking the place of tumbles. In the forward swimming, T. mauritanica shows a very efficient flagellar beat, with undulatory retrograde waves that run along the flagella to their tip. In the backward swimming, the flagella show a nonstereotypical synchronization mode, with a pattern that does not fit any of the modes present in the other Chlamydomonadales so far investigatedSource: Journal of phycology 52 (2016): 209–218. doi:10.1111/jpy.12384
DOI: 10.1111/jpy.12384
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ISTI Repository | Journal of Phycology | onlinelibrary.wiley.com | CNR ExploRA
2014
Journal article
Restricted
Water monitoring: automated and real time identification and classification of algae using digital microscopy
Coltelli P., Barsanti L., Evangelista V., Frassanito A., Gualtieri P.
Microalgae are unicellular photoautotrophs that grow in any habitat from fresh and saline water bodies, to hot springs and ice. Microalgae can be used as indicators to monitor water ecosystem conditions. These organisms react quickly and predictably to a broad range of environmental stressors, thus providing early signals of a changing environment. When grown extensively, microalgae may produce harmful effects on marine or freshwater ecology and fishery resources. Rapid and accurate recognition and classification of microalgae is one of the most important issues in water resource management. In this paper, a methodology for automatic and real time identification and enumeration of microalgae by means of image analysis is presented. The methodology is based on segmentation, shape feature extraction, pigment signature determination and neural network grouping; it attained 98.6% accuracy from a set of 53 869 images of 23 different microalgae representing the major algal phyla. In our opinion this methodology partly overcomes the lack of automated identification systems and is on the forefront of developing a computer-based image processing technique to automatically detect recognize, identify and enumerate microalgae genera and species from all the divisions. This methodology could be useful for an appropriate and effective water resource management.Source: Environmental science - processes and impacts 16 (2014): 2656–2665. doi:10.1039/c4em00451e
DOI: 10.1039/c4em00451e
Metrics:
Coltelli P., Barsanti L., Evangelista V., Frassanito A., Gualtieri P.
Microalgae are unicellular photoautotrophs that grow in any habitat from fresh and saline water bodies, to hot springs and ice. Microalgae can be used as indicators to monitor water ecosystem conditions. These organisms react quickly and predictably to a broad range of environmental stressors, thus providing early signals of a changing environment. When grown extensively, microalgae may produce harmful effects on marine or freshwater ecology and fishery resources. Rapid and accurate recognition and classification of microalgae is one of the most important issues in water resource management. In this paper, a methodology for automatic and real time identification and enumeration of microalgae by means of image analysis is presented. The methodology is based on segmentation, shape feature extraction, pigment signature determination and neural network grouping; it attained 98.6% accuracy from a set of 53 869 images of 23 different microalgae representing the major algal phyla. In our opinion this methodology partly overcomes the lack of automated identification systems and is on the forefront of developing a computer-based image processing technique to automatically detect recognize, identify and enumerate microalgae genera and species from all the divisions. This methodology could be useful for an appropriate and effective water resource management.Source: Environmental science - processes and impacts 16 (2014): 2656–2665. doi:10.1039/c4em00451e
DOI: 10.1039/c4em00451e
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Environmental Science Processes & Impacts | CNR ExploRA
2013
Journal article
Restricted
Automatic and real time recognition of microalgae by means of pigment signature and shape
Coltelli P., Barsanti L., Evangelista V., Frassanito A. M., Passarelli V., Gualtieri P.
Microalgae are unicellular photoautotrophic organisms that grow in any habitat such as fresh and salt water bodies, hot springs, ice, air, and in or on other organisms and substrates. Massive growth of microalgae may produce harmful effects on the marine and freshwater ecological environment and fishery resources. Therefore, rapid and accurate recognition and classification of microalgae is one of the most important issues in water resource management. In this paper, a new methodology for automatic and real time identification of microalgae by means of microscopy image analysis is presented. This methodology is based on segmentation, shape features extraction, and characteristic colour (i.e. pigment signature) determination. A classifier algorithm based on the minimum distance criterion was used for microalgae grouping according to the measured features. 96.6% accuracy from a set of 3423 images of 24 different microalgae representing the major algal phyla was achieved by this methodology.Source: Environmental science--processes & impacts. 15 (2013): 1397–1410. doi:10.1039/C3EM00160A
DOI: 10.1039/c3em00160a
Metrics:
Coltelli P., Barsanti L., Evangelista V., Frassanito A. M., Passarelli V., Gualtieri P.
Microalgae are unicellular photoautotrophic organisms that grow in any habitat such as fresh and salt water bodies, hot springs, ice, air, and in or on other organisms and substrates. Massive growth of microalgae may produce harmful effects on the marine and freshwater ecological environment and fishery resources. Therefore, rapid and accurate recognition and classification of microalgae is one of the most important issues in water resource management. In this paper, a new methodology for automatic and real time identification of microalgae by means of microscopy image analysis is presented. This methodology is based on segmentation, shape features extraction, and characteristic colour (i.e. pigment signature) determination. A classifier algorithm based on the minimum distance criterion was used for microalgae grouping according to the measured features. 96.6% accuracy from a set of 3423 images of 24 different microalgae representing the major algal phyla was achieved by this methodology.Source: Environmental science--processes & impacts. 15 (2013): 1397–1410. doi:10.1039/C3EM00160A
DOI: 10.1039/c3em00160a
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Environmental Science Processes & Impacts | pubs.rsc.org | CNR ExploRA
2009
Journal article
Restricted
Microspectrophotometry as a method to identify kleptoplastids in the naked freshwater Dinoflagellate Gymnodinium Acidotum
Barsanti L., Evangelista V., Passarelli V., Frassanito A, Coltelli P., Gualtieri P.
A relatively small number of freshwater dinoflagellates are involved in symbiotic association with cryptophytes. The chloroplasts of the cryptophytes are retained by the dinoflagellate and give it the characteristic phycobilin pigmentation, either phycoerythrin or phycocyanin. The pigment characterization of the retained chloroplasts can give precise and accurate information about the type of cryptophyte preyed upon by the dinoflagellate. For this purpose, we performed microspectrophotometric evaluation of the pigments of Gymnodinium acidotum Nygaard and three different cryptophytes present in samples collected from a tributary of the river Arno, in Tuscany (Italy). The comparison of the different spectroscopic data allowed us to discriminate effectively among the cryptophytes preyed upon by the dinoflagellate.Source: Journal of phycology 45 (2009): 1304–1309. doi:10.1111/j.1529-8817.2009.00751.x
DOI: 10.1111/j.1529-8817.2009.00751.x
Metrics:
Barsanti L., Evangelista V., Passarelli V., Frassanito A, Coltelli P., Gualtieri P.
A relatively small number of freshwater dinoflagellates are involved in symbiotic association with cryptophytes. The chloroplasts of the cryptophytes are retained by the dinoflagellate and give it the characteristic phycobilin pigmentation, either phycoerythrin or phycocyanin. The pigment characterization of the retained chloroplasts can give precise and accurate information about the type of cryptophyte preyed upon by the dinoflagellate. For this purpose, we performed microspectrophotometric evaluation of the pigments of Gymnodinium acidotum Nygaard and three different cryptophytes present in samples collected from a tributary of the river Arno, in Tuscany (Italy). The comparison of the different spectroscopic data allowed us to discriminate effectively among the cryptophytes preyed upon by the dinoflagellate.Source: Journal of phycology 45 (2009): 1304–1309. doi:10.1111/j.1529-8817.2009.00751.x
DOI: 10.1111/j.1529-8817.2009.00751.x
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Journal of Phycology | onlinelibrary.wiley.com | CNR ExploRA
2009
Journal article
Restricted
In vivo absorption spectra of the two stable states of the Euglena photoreceptor photocycle
Barsanti L., Coltelli P., Evangelista V., Passarelli V., Frassanito A. M., Vesentini N., Santoro F., Gualtieri P.
Euglena gracilis possesses a simple but sophisticated light detecting system, consisting of an eyespot formed by carotenoids globules and a photoreceptor. The photoreceptor of Euglena is characterized by optical bistability, with two stable states. In order to provide important and discriminating information on the series of structural changes that Euglena photoreceptive protein(s) undergoes inside the photoreceptor in response to light, we measured the in vivo absorption spectra of the two stable states A and B of photoreceptor photocycle. Data were collected using two different devices, i.e. a microspectrophotometer and a digital microscope. Our results show that the photocycle and the absorption spectra of the photoreceptor possess strong spectroscopic similarities with a rhodopsin-like protein. Moreover, the analysis of the absorption spectra of the two stable states of the photoreceptor and the absorption spectrum of the eyespot suggests an intriguing hypothesis for the orientation of microalgae toward light.Source: Photochemistry and photobiology 85 (2009): 304–312. doi:10.1111 / j.1751-1097.2007.00438.x
DOI: 10.1111/j.1751-1097.2007.00438.x
Metrics:
Barsanti L., Coltelli P., Evangelista V., Passarelli V., Frassanito A. M., Vesentini N., Santoro F., Gualtieri P.
Euglena gracilis possesses a simple but sophisticated light detecting system, consisting of an eyespot formed by carotenoids globules and a photoreceptor. The photoreceptor of Euglena is characterized by optical bistability, with two stable states. In order to provide important and discriminating information on the series of structural changes that Euglena photoreceptive protein(s) undergoes inside the photoreceptor in response to light, we measured the in vivo absorption spectra of the two stable states A and B of photoreceptor photocycle. Data were collected using two different devices, i.e. a microspectrophotometer and a digital microscope. Our results show that the photocycle and the absorption spectra of the photoreceptor possess strong spectroscopic similarities with a rhodopsin-like protein. Moreover, the analysis of the absorption spectra of the two stable states of the photoreceptor and the absorption spectrum of the eyespot suggests an intriguing hypothesis for the orientation of microalgae toward light.Source: Photochemistry and photobiology 85 (2009): 304–312. doi:10.1111 / j.1751-1097.2007.00438.x
DOI: 10.1111/j.1751-1097.2007.00438.x
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2009
Journal article
Restricted
Intramolecular photo-switching and intermolecular energy transfer as primary photoevents in photoreceptive processes: the case of Euglena gracilis
Mercatelli R., Quercioli F., Barsanti L., Evangelista V., Coltelli P., Passarelli V., Frassanito A. M., Gualtieri P.
In this paper we report the results of measurements performed by FLIM on the photoreceptor of Euglenagracilis. This organelle consists of optically bistable proteins, characterized by two thermally stable isomeric forms: A(498,) non fluorescent and B(462), fluorescent. Our data indicate that the primary photoevent of Euglena photoreception upon photon absorption consists of two contemporaneous different phenomena: an intramolecular photo-switch (i.e., A(498) becomes B(462)), and a intermolecular and unidirectional Forster-type energy transfer. During the FRET process, the fluorescent B(462) form acts as donor for the non-fluorescent A(498) form of the protein nearby, which acts as acceptor. We hypothesize that in nature these phenomena follow each other with a domino progression along the orderly organized and closely packed proteins in the photoreceptor layer(s), modulating the isomeric composition of the photoreceptive protein pool. This mechanism guarantees that few photons are sufficient to produce a signal detectable by the cell.Source: Biochemical and biophysical research communications (Print) 385 (2009): 176–180. doi:10.1016/j.envres.2007.01.011
DOI: 10.1016/j.envres.2007.01.011
Metrics:
Mercatelli R., Quercioli F., Barsanti L., Evangelista V., Coltelli P., Passarelli V., Frassanito A. M., Gualtieri P.
In this paper we report the results of measurements performed by FLIM on the photoreceptor of Euglenagracilis. This organelle consists of optically bistable proteins, characterized by two thermally stable isomeric forms: A(498,) non fluorescent and B(462), fluorescent. Our data indicate that the primary photoevent of Euglena photoreception upon photon absorption consists of two contemporaneous different phenomena: an intramolecular photo-switch (i.e., A(498) becomes B(462)), and a intermolecular and unidirectional Forster-type energy transfer. During the FRET process, the fluorescent B(462) form acts as donor for the non-fluorescent A(498) form of the protein nearby, which acts as acceptor. We hypothesize that in nature these phenomena follow each other with a domino progression along the orderly organized and closely packed proteins in the photoreceptor layer(s), modulating the isomeric composition of the photoreceptive protein pool. This mechanism guarantees that few photons are sufficient to produce a signal detectable by the cell.Source: Biochemical and biophysical research communications (Print) 385 (2009): 176–180. doi:10.1016/j.envres.2007.01.011
DOI: 10.1016/j.envres.2007.01.011
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Environmental Research | www.sciencedirect.com | CNR ExploRA
2008
Contribution to book
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Oddities and curiosities in the algal world
Barsanti L., Coltelli P., Evangelista V., Frassanito A. M., Passatelli V., Vesentini N., Gualtieri P.
The term algae refers to a polyphyletic, non-cohesive and artificial assemblage, of O2-evolving, photosynthetic organisms. The profound diversity of size, shape, habitat, metabolic traits and growth strategies makes this heterogeneous assemblage of both prokaryotic and eukaryotic species an almost unlimited source of curious and unusual features. Algae display an incredible adaptability to most environments, and provide an excellent system for testing hypotheses concerning the evolution of ecological tolerance. In fact, they are not limited to temperate waters, but can survive at very low depth and very low irradiance, and thrive beneath polar ice sheets. Upon adaptation to life on land, algae have colonized such surprising places, as catacombs, tree trunks, hot springs, and can also resist desiccation in the desert regions of the world. Moreover, relations between them and other organisms, which include competition within and between species for space, light, nutrient or any limiting source, are based on a variety of associations, which includes epiphytism, parasitism, and symbiosis. Algae can share their life with animals, growing on sloth hair, inside the jelly capsule of amphibian eggs, upon the carapaces of turtles or shells of mollusks, camouflaging the dorsal scute of harvestmen. They can also light up the sea at night, and cause infections in animals and humans.Source: Algal Toxins: Nature, Occurrence, Effect and Detection, edited by Valtere Evangelista, Laura Barsanti, Anna Maria Frassanito, Vincenzo Passarelli, Paolo Gualtieri, pp. 353–391. Dordrecht: Springer, 2008
DOI: 10.1007/978-1-4020-8480-5_17
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Barsanti L., Coltelli P., Evangelista V., Frassanito A. M., Passatelli V., Vesentini N., Gualtieri P.
The term algae refers to a polyphyletic, non-cohesive and artificial assemblage, of O2-evolving, photosynthetic organisms. The profound diversity of size, shape, habitat, metabolic traits and growth strategies makes this heterogeneous assemblage of both prokaryotic and eukaryotic species an almost unlimited source of curious and unusual features. Algae display an incredible adaptability to most environments, and provide an excellent system for testing hypotheses concerning the evolution of ecological tolerance. In fact, they are not limited to temperate waters, but can survive at very low depth and very low irradiance, and thrive beneath polar ice sheets. Upon adaptation to life on land, algae have colonized such surprising places, as catacombs, tree trunks, hot springs, and can also resist desiccation in the desert regions of the world. Moreover, relations between them and other organisms, which include competition within and between species for space, light, nutrient or any limiting source, are based on a variety of associations, which includes epiphytism, parasitism, and symbiosis. Algae can share their life with animals, growing on sloth hair, inside the jelly capsule of amphibian eggs, upon the carapaces of turtles or shells of mollusks, camouflaging the dorsal scute of harvestmen. They can also light up the sea at night, and cause infections in animals and humans.Source: Algal Toxins: Nature, Occurrence, Effect and Detection, edited by Valtere Evangelista, Laura Barsanti, Anna Maria Frassanito, Vincenzo Passarelli, Paolo Gualtieri, pp. 353–391. Dordrecht: Springer, 2008
DOI: 10.1007/978-1-4020-8480-5_17
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2008
Journal article
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Low-resolution characterization of the 3D structure of the Euglena gracilis photoreceptor
Barsanti L., Coltelli P., Evangelista V., Passarelli V., Frassanito A. M., Vesentini N., Gualtieri P.
This paper deals with the first characterization of the structure of the photoreceptive organelle of the unicellular alga Euglena gracilis (Euglenophyta). This organelle has a three-dimensional organization consisting of up to 50 closely stacked membrane lamellae. Ionically induced unstacking of the photoreceptor lamellae revealed ordered arrays well suited to structural analysis by electron microscopy and image analysis, which ultimately yielded a low-resolution picture of the structure. Each lamella is formed by the photoreceptive membrane protein of the cell assembled within the membrane layer in a hexagonal lattice. The first order diffraction spots in the calculated Fourier transform reveals the presence of 6-fold symmetrized topography (better resolution about 90A). The 2D and 3D structural data are very similar with those recently published on proteorodopsin, a membrane protein used by marine bacterio-plankton as light-driven proton pump. In our opinion these similarity indicate that a photoreceptive protein belonging to the same superfamily of proteorodopsin could form the Euglena photoreceptor.Source: Biochemical and biophysical research communications (Print) 375 (2008): 471–476. doi:10.1016/j.bbrc.2008.08.045
DOI: 10.1016/j.bbrc.2008.08.045
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Barsanti L., Coltelli P., Evangelista V., Passarelli V., Frassanito A. M., Vesentini N., Gualtieri P.
This paper deals with the first characterization of the structure of the photoreceptive organelle of the unicellular alga Euglena gracilis (Euglenophyta). This organelle has a three-dimensional organization consisting of up to 50 closely stacked membrane lamellae. Ionically induced unstacking of the photoreceptor lamellae revealed ordered arrays well suited to structural analysis by electron microscopy and image analysis, which ultimately yielded a low-resolution picture of the structure. Each lamella is formed by the photoreceptive membrane protein of the cell assembled within the membrane layer in a hexagonal lattice. The first order diffraction spots in the calculated Fourier transform reveals the presence of 6-fold symmetrized topography (better resolution about 90A). The 2D and 3D structural data are very similar with those recently published on proteorodopsin, a membrane protein used by marine bacterio-plankton as light-driven proton pump. In our opinion these similarity indicate that a photoreceptive protein belonging to the same superfamily of proteorodopsin could form the Euglena photoreceptor.Source: Biochemical and biophysical research communications (Print) 375 (2008): 471–476. doi:10.1016/j.bbrc.2008.08.045
DOI: 10.1016/j.bbrc.2008.08.045
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Biochemical and Biophysical Research Communications | www.sciencedirect.com | CNR ExploRA
2008
Journal article
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An automatic real-time system for the determination of translational and rotational speeds of swimming micro-organisms
Coltelli P., Evangelisti M., Evangelista V., Gualtieri P.
This paper describes a digital system designed for the automatic detection and measurement of the velocity of moving objects in images acquired by means of a common TV-camera mounted onto a microscope. The main real-time features are: . it can perform a real-time grey level difference between two successive frames in order to detect moving objects . it stores the images in the frame memory . it performs an automatic labelisation in order to recognise the moving micro-organisms . it calculates the area of the cells moving in the microscope field . it completes the analysis in few seconds.Source: International journal of signal and imaging systems engineering (Print) 1 (2008): 25–29. doi:10.1504/IJSISE.2008.017770
DOI: 10.1504/ijsise.2008.017770
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Coltelli P., Evangelisti M., Evangelista V., Gualtieri P.
This paper describes a digital system designed for the automatic detection and measurement of the velocity of moving objects in images acquired by means of a common TV-camera mounted onto a microscope. The main real-time features are: . it can perform a real-time grey level difference between two successive frames in order to detect moving objects . it stores the images in the frame memory . it performs an automatic labelisation in order to recognise the moving micro-organisms . it calculates the area of the cells moving in the microscope field . it completes the analysis in few seconds.Source: International journal of signal and imaging systems engineering (Print) 1 (2008): 25–29. doi:10.1504/IJSISE.2008.017770
DOI: 10.1504/ijsise.2008.017770
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International Journal of Signal and Imaging Systems Engineering | www.inderscience.com | CNR ExploRA
2008
Contribution to book
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The world of algae
Barsanti L., Coltelli P., Evangelista V., Frassanito A. M., Passarelli V., Vesentini N., Gualtieri P.
In the following sections of this chapter we will try to give an outline of some algae characteristics and general information on their classification, distribution, structure, nutrition and reproduction. In the last paragraph a short account on the origin of eukaryotic algae is set out.Source: Algal Toxins: Nature, Occurrence, Effect and Detection, edited by Valtere Evangelista, Laura Barsanti, Anna Maria Frassanito, Vincenzo Passarelli, Paolo Gualtieri, pp. 1–15, 2008
DOI: 10.1007/978-1-4020-8480-5_1
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Barsanti L., Coltelli P., Evangelista V., Frassanito A. M., Passarelli V., Vesentini N., Gualtieri P.
In the following sections of this chapter we will try to give an outline of some algae characteristics and general information on their classification, distribution, structure, nutrition and reproduction. In the last paragraph a short account on the origin of eukaryotic algae is set out.Source: Algal Toxins: Nature, Occurrence, Effect and Detection, edited by Valtere Evangelista, Laura Barsanti, Anna Maria Frassanito, Vincenzo Passarelli, Paolo Gualtieri, pp. 1–15, 2008
DOI: 10.1007/978-1-4020-8480-5_1
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2007
Journal article
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Real-time measurement and analysis of translational and rotational speeds of moving objects in microscope fields
Coltelli P., Evangelisti M., Evangelista V., Gualtieri P.
This paper describes a digital system designed for the automatic detection and measurement of the velocity of moving objects in images acquired by means of a common TV-camera mounted onto a microscope. The main characteristics of this system are the following: 1) it can perform a realtime gray level difference between two successive frames in order to detect moving objects and to suppress stationary objects (subtraction procedure); usually the delay between two successive frames varies linearly from 40 msec to 1920 msec; 2) it reduces the size of images resulting from the subtraction procedure (difference images) and stores them in the frame memory; the result of these operation, all performed in real-time, is a film of time sequences; 3) it performs an automatic labelization in order to recognize the moving microorganisms and to calculate their area in each difference image; 4) it calculates and plots the variation of the average area of the cells moving in the microscope field; 5) it completes the analysis in few seconds.Source: Lecture notes in computer science 4826 (2007): 128–135.
Coltelli P., Evangelisti M., Evangelista V., Gualtieri P.
This paper describes a digital system designed for the automatic detection and measurement of the velocity of moving objects in images acquired by means of a common TV-camera mounted onto a microscope. The main characteristics of this system are the following: 1) it can perform a realtime gray level difference between two successive frames in order to detect moving objects and to suppress stationary objects (subtraction procedure); usually the delay between two successive frames varies linearly from 40 msec to 1920 msec; 2) it reduces the size of images resulting from the subtraction procedure (difference images) and stores them in the frame memory; the result of these operation, all performed in real-time, is a film of time sequences; 3) it performs an automatic labelization in order to recognize the moving microorganisms and to calculate their area in each difference image; 4) it calculates and plots the variation of the average area of the cells moving in the microscope field; 5) it completes the analysis in few seconds.Source: Lecture notes in computer science 4826 (2007): 128–135.
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2007
Contribution to book
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Statistical analysis of microspectroscopy signals for algae classification and phylogenetic comparison
Tonazzini A., Coltelli P., Gualtieri P.
We performed microspectroscopic evaluation of the pigment composition of the photosynthetic compartments of algae belonging to different taxonomic divisions and higher plants. In cite{Bar07}, a supervised Gaussian bands decompositions was performed for the pigment spectra, the algae spectrum was modelled as the linear mixture, with unknown coefficients, of the pigment spectra, and a user-guided fitting algorithm was employed. The method provided a reliable discrimination among chlorophylls $a$, $b$ and $c$, phycobiliproteins and carotenoids. Comparative analysis of absorption spectra highlighted the evolutionary grouping of the algae into three main lineages in accordance with the most recent endosymbiotic theories. In this paper, we adopt an unsupervised statistical estimation approach to automatically perform both Gaussian bands decomposition of the pigments and algae fitting. In a fully Bayesian setting, we propose estimating both the algae mixture coefficients and the parameters of the pigment spectra decomposition, on the basis of the alga spectrum alone. As a priori information to stabilize this highly underdetermined problem, templates for the pigment spectra are assumed to be available, though, due to their measurements outside the protein moiety, they differ in shape from the real spectra of the pigments present in nature by unknown, slight displacements and contraction/dilatation factors. We propose a classification system subdivided into two phases. In the first, the learning phase, the parameters of the Gaussians decomposition and the shape factors are estimated. In the second phase, the classification phase, the now known real spectra of the pigments are used as a base set to fit any other spectrum of algae. The unsupervised method provided results comparable to those of the previous, supervised method.Source: Advances in Mass Data Analysis of Signals and Images in Medicine, Biotechnology and Chemistry, edited by Petra Perner and Ovidio Salvetti, pp. 58–68, 2007
DOI: 10.1007/978-3-540-76300-0
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Tonazzini A., Coltelli P., Gualtieri P.
We performed microspectroscopic evaluation of the pigment composition of the photosynthetic compartments of algae belonging to different taxonomic divisions and higher plants. In cite{Bar07}, a supervised Gaussian bands decompositions was performed for the pigment spectra, the algae spectrum was modelled as the linear mixture, with unknown coefficients, of the pigment spectra, and a user-guided fitting algorithm was employed. The method provided a reliable discrimination among chlorophylls $a$, $b$ and $c$, phycobiliproteins and carotenoids. Comparative analysis of absorption spectra highlighted the evolutionary grouping of the algae into three main lineages in accordance with the most recent endosymbiotic theories. In this paper, we adopt an unsupervised statistical estimation approach to automatically perform both Gaussian bands decomposition of the pigments and algae fitting. In a fully Bayesian setting, we propose estimating both the algae mixture coefficients and the parameters of the pigment spectra decomposition, on the basis of the alga spectrum alone. As a priori information to stabilize this highly underdetermined problem, templates for the pigment spectra are assumed to be available, though, due to their measurements outside the protein moiety, they differ in shape from the real spectra of the pigments present in nature by unknown, slight displacements and contraction/dilatation factors. We propose a classification system subdivided into two phases. In the first, the learning phase, the parameters of the Gaussians decomposition and the shape factors are estimated. In the second phase, the classification phase, the now known real spectra of the pigments are used as a base set to fit any other spectrum of algae. The unsupervised method provided results comparable to those of the previous, supervised method.Source: Advances in Mass Data Analysis of Signals and Images in Medicine, Biotechnology and Chemistry, edited by Petra Perner and Ovidio Salvetti, pp. 58–68, 2007
DOI: 10.1007/978-3-540-76300-0
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2007
Report
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2005
Conference article
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A relational query primitive for constraint-based pattern mining
Bonchi F., Giannotti F., Pedreschi D.
As a step towards the design of an Inductive Database Sys- tem, in this paper we present a primitive for constraint-based frequent pattern mining, which represents a careful trade-o between expressive- ness and eciency Such primitive is a simple mechanism which takes a relational table in input and extracts from it all frequent patterns which satisfy a given set of user-de ned constraints. Despite its simplicity, the proposed primitive is expressive enough to deal with a broad range of interesting constraint-based frequent pattern queries,using a comprehen- sive repertoire of constraints de ned over SQL aggregates. Thanks to its simplicity, the proposed primitive is amenable to be smoothly embedded in a variety of data mining query languages and be eciencly xecuted, by the state-of-the-art optimization techniques based on pushing the var- ious form of constraints by means of data reduction.Source: European Workshop on Inductive Databases and Constraint Based Mining, pp. 14–37, Hinterzarten, Germany, 11-13 March 2004
Bonchi F., Giannotti F., Pedreschi D.
As a step towards the design of an Inductive Database Sys- tem, in this paper we present a primitive for constraint-based frequent pattern mining, which represents a careful trade-o between expressive- ness and eciency Such primitive is a simple mechanism which takes a relational table in input and extracts from it all frequent patterns which satisfy a given set of user-de ned constraints. Despite its simplicity, the proposed primitive is expressive enough to deal with a broad range of interesting constraint-based frequent pattern queries,using a comprehen- sive repertoire of constraints de ned over SQL aggregates. Thanks to its simplicity, the proposed primitive is amenable to be smoothly embedded in a variety of data mining query languages and be eciencly xecuted, by the state-of-the-art optimization techniques based on pushing the var- ious form of constraints by means of data reduction.Source: European Workshop on Inductive Databases and Constraint Based Mining, pp. 14–37, Hinterzarten, Germany, 11-13 March 2004
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2005
Other
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A dedicated interface to plan scenes with virtual characters
Palamidese P., Coltelli P.
This paper discusses how to design a multimedia application in which a number of characters perform a predefined set of actions. The basic concepts and techniques required by this kind of application include character animation, storytelling, and multimedia. This paper focuses on the prototyping issues and the designer need of making the starting plan of the whole story. The design process requires mainly the composition and integration of narrative structures and media and animated objects. We propose to integrate multimedia authoring styles and animation synthesis techniques to simplify and speed up designing, prototyping and editing. We state that available animation systems do not provide a suitable interface for developing large-scale applications and supporting non-expert authors. Sketching and planning stories containing human characters requires an animation tool dedicated to it. A story can be prototyped rapidly only if the interface supports the author expressly.
Palamidese P., Coltelli P.
This paper discusses how to design a multimedia application in which a number of characters perform a predefined set of actions. The basic concepts and techniques required by this kind of application include character animation, storytelling, and multimedia. This paper focuses on the prototyping issues and the designer need of making the starting plan of the whole story. The design process requires mainly the composition and integration of narrative structures and media and animated objects. We propose to integrate multimedia authoring styles and animation synthesis techniques to simplify and speed up designing, prototyping and editing. We state that available animation systems do not provide a suitable interface for developing large-scale applications and supporting non-expert authors. Sketching and planning stories containing human characters requires an animation tool dedicated to it. A story can be prototyped rapidly only if the interface supports the author expressly.
See at: CNR ExploRA