Lorian Straker | Universidade Federal do Rio de Janeiro (UFRJ) (original) (raw)

Papers by Lorian Straker

Research paper thumbnail of Rapid mobilization of abdominal fat in migrating eared grebes

Journal of Avian Biology, 2016

Research paper thumbnail of Quantitative characterization and comparative study of feather melanosome internal morphology using surface analysis

Research paper thumbnail of How seabirds plunge-dive without injuries

Proceedings of the National Academy of Sciences, 2016

Research paper thumbnail of Primeiro registro de Tangara preciosa (Cabanis, 1851) para o estado de Minas Gerais, Brasil (Passeriformes: Emberizidae)

Ararajuba, 2008

CITATIONS 2 READS 52 4 authors, including:

Research paper thumbnail of Diving dynamics of seabirds

Bulletin of the American Physical Society, Mar 4, 2015

Diving dynamics of seabirds SUNGHWAN JUNG, BRIAN CHANG, MATT CROSON, Virginia Tech, LORIAN STRAKE... more Diving dynamics of seabirds SUNGHWAN JUNG, BRIAN CHANG, MATT CROSON, Virginia Tech, LORIAN STRAKER, CARLA DOVE, Smithonian Museum -Diving is the activity of falling from air into water, which is somewhat dangerous due to the impact. Humans dive for entertainments less than 20 meters high, however seabirds dive as a hunting mechanism from more than 20 meters high. Moreover, most birds including seabirds have a slender and long neck compared to many other animals, which can potentially be the weakest part of the body upon axial impact compression. Motivated by the diving dynamics, we investigate the effect of surface and geometric configurations on structures consisting of a beaklike cone and a neck-like elastic beam. A transition from non-buckling to buckling is characterized and understood through physical experiments and an analytical model.

Research paper thumbnail of Toxoplasma gondii Inside LLCMK2 Cells. A Study by Field Emission Scanning and Transmission Electron Microscopy

Microscopy and Microanalysis, Aug 1, 2003

INTRODUCTION: Transmission electron microscopy (TEM) of ultrathin sections has been, for decades,... more INTRODUCTION: Transmission electron microscopy (TEM) of ultrathin sections has been, for decades, the classical tool for studying intracellular structures and organelles. The intrinsic limitations of bi-dimensional images have been partially overcome by 3-D reconstruction from serial ...

Research paper thumbnail of Comment on "A Diverse Assemblage of Late Cretaceous Dinosaur and Bird Feathers from Canadian Amber

Research paper thumbnail of Primeiro registro de Tangara preciosa (Cabanis, 1851) para o estado de Minas Gerais, Brasil (Passeriformes: Emberizidae)

Revista Brasileira de …

CITATIONS 2 READS 52 4 authors, including:

Research paper thumbnail of Preparation for Microstructure Analysis of Feathers in Scanning Electron Microscopy (Sem)

Research paper thumbnail of MULTIPLE APPROACHES IN THE STUDY OF THE ULTRASTRUCTURE OF THE CONOID OF Toxoplasma gondii

The user has requested enhancement of the downloaded file.

Research paper thumbnail of Interrelations between the Parasitophorous Vacuole of Toxoplasma gondii and Host Cell Organelles

Microscopy and Microanalysis, 2005

Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and m... more Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and multiplying in any nucleated cell of warm-blooded animals. Its survival strategies include escape from fusion of the parasitophorous vacuole with host cell lysosomes and rearrangement of host cell organelles in relation to the parasitophorous vacuole. In this article we report the rearrangement of host cell organelles and elements of the cytoskeleton of LLCMK2 cells, a lineage derived from green monkey kidney epithelial cells, in response to infection by T. gondii tachyzoites. Transmission electron microscopy made on flat embedded monolayers cut horizontally to the apical side of the cells or field emission scanning electron microscopy of monolayers scraped with scotch tape before sputtering showed that association of mitochondria to the vacuole is much less frequent than previously described. On the other hand, all parasitophorous vacuoles were surrounded by elements of the endoplasmic reticulum. These data were complemented by observations by laser scanning microscopy using fluorescent probes from mitochondria and endoplasmic reticulum and reinforced by three-dimensional reconstruction from serial sections observed by transmission electron microscopy and labeling of mitochondria and endoplasmic reticulum by fluorescent probes.

Research paper thumbnail of Interrelations between the Parasitophorous Vacuole of Toxoplasma gondii and Host Cell Organelles

Microscopy and Microanalysis, 2005

Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and m... more Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and multiplying in any nucleated cell of warm-blooded animals. Its survival strategies include escape from fusion of the parasitophorous vacuole with host cell lysosomes and rearrangement of host cell organelles in relation to the parasitophorous vacuole. In this article we report the rearrangement of host cell organelles and elements of the cytoskeleton of LLCMK2 cells, a lineage derived from green monkey kidney epithelial cells, in response to infection by T. gondii tachyzoites. Transmission electron microscopy made on flat embedded monolayers cut horizontally to the apical side of the cells or field emission scanning electron microscopy of monolayers scraped with scotch tape before sputtering showed that association of mitochondria to the vacuole is much less frequent than previously described. On the other hand, all parasitophorous vacuoles were surrounded by elements of the endoplasmic reticulum. These data were complemented by observations by laser scanning microscopy using fluorescent probes from mitochondria and endoplasmic reticulum and reinforced by three-dimensional reconstruction from serial sections observed by transmission electron microscopy and labeling of mitochondria and endoplasmic reticulum by fluorescent probes.

Research paper thumbnail of Spina cortica and Tapetum spinosus, two new microstructures of flight feathers: Description, function and distribution in modern birds

Journal of Structural Biology, 2008

The importance of feathers for the avian group has made them one of the most studied epidermal st... more The importance of feathers for the avian group has made them one of the most studied epidermal structures both from the morphological and evolutionary point of view. Surprisingly, our observations by Scanning Electron Microscopy detected the presence of two structures widely distributed within different avian groups and not yet described. In this paper we describe these two new structures (Spina cortica and Tapetum spinosus) and map their distribution within modern birds. The S. cortica is a thorn-like microstructure that grows on the barb cortex and the T. spinosus is the assemblage of these thorns. The distribution of these new structures among birds and their morphological diversity could be of great interest to taxonomists and evolutionary biologists interested in the origin of bird flight.

Research paper thumbnail of Spina cortica and Tapetum spinosus, two new microstructures of flight feathers: Description, function and distribution in modern birds

The importance of feathers for the avian group has made them one of the most studied epidermal st... more The importance of feathers for the avian group has made them one of the most studied epidermal structures both from the morphological and evolutionary point of view. Surprisingly, our observations by Scanning Electron Microscopy detected the presence of two structures widely distributed within different avian groups and not yet described. In this paper we describe these two new structures (Spina cortica and Tapetum spinosus) and map their distribution within modern birds. The S. cortica is a thorn-like microstructure that grows on the barb cortex and the T. spinosus is the assemblage of these thorns. The distribution of these new structures among birds and their morphological diversity could be of great interest to taxonomists and evolutionary biologists interested in the origin of bird flight.

Research paper thumbnail of Rapid mobilization of abdominal fat in migrating eared grebes

Journal of Avian Biology, 2016

Research paper thumbnail of Quantitative characterization and comparative study of feather melanosome internal morphology using surface analysis

Research paper thumbnail of How seabirds plunge-dive without injuries

Proceedings of the National Academy of Sciences, 2016

Research paper thumbnail of Primeiro registro de Tangara preciosa (Cabanis, 1851) para o estado de Minas Gerais, Brasil (Passeriformes: Emberizidae)

Ararajuba, 2008

CITATIONS 2 READS 52 4 authors, including:

Research paper thumbnail of Diving dynamics of seabirds

Bulletin of the American Physical Society, Mar 4, 2015

Diving dynamics of seabirds SUNGHWAN JUNG, BRIAN CHANG, MATT CROSON, Virginia Tech, LORIAN STRAKE... more Diving dynamics of seabirds SUNGHWAN JUNG, BRIAN CHANG, MATT CROSON, Virginia Tech, LORIAN STRAKER, CARLA DOVE, Smithonian Museum -Diving is the activity of falling from air into water, which is somewhat dangerous due to the impact. Humans dive for entertainments less than 20 meters high, however seabirds dive as a hunting mechanism from more than 20 meters high. Moreover, most birds including seabirds have a slender and long neck compared to many other animals, which can potentially be the weakest part of the body upon axial impact compression. Motivated by the diving dynamics, we investigate the effect of surface and geometric configurations on structures consisting of a beaklike cone and a neck-like elastic beam. A transition from non-buckling to buckling is characterized and understood through physical experiments and an analytical model.

Research paper thumbnail of Toxoplasma gondii Inside LLCMK2 Cells. A Study by Field Emission Scanning and Transmission Electron Microscopy

Microscopy and Microanalysis, Aug 1, 2003

INTRODUCTION: Transmission electron microscopy (TEM) of ultrathin sections has been, for decades,... more INTRODUCTION: Transmission electron microscopy (TEM) of ultrathin sections has been, for decades, the classical tool for studying intracellular structures and organelles. The intrinsic limitations of bi-dimensional images have been partially overcome by 3-D reconstruction from serial ...

Research paper thumbnail of Comment on "A Diverse Assemblage of Late Cretaceous Dinosaur and Bird Feathers from Canadian Amber

Research paper thumbnail of Primeiro registro de Tangara preciosa (Cabanis, 1851) para o estado de Minas Gerais, Brasil (Passeriformes: Emberizidae)

Revista Brasileira de …

CITATIONS 2 READS 52 4 authors, including:

Research paper thumbnail of Preparation for Microstructure Analysis of Feathers in Scanning Electron Microscopy (Sem)

Research paper thumbnail of MULTIPLE APPROACHES IN THE STUDY OF THE ULTRASTRUCTURE OF THE CONOID OF Toxoplasma gondii

The user has requested enhancement of the downloaded file.

Research paper thumbnail of Interrelations between the Parasitophorous Vacuole of Toxoplasma gondii and Host Cell Organelles

Microscopy and Microanalysis, 2005

Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and m... more Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and multiplying in any nucleated cell of warm-blooded animals. Its survival strategies include escape from fusion of the parasitophorous vacuole with host cell lysosomes and rearrangement of host cell organelles in relation to the parasitophorous vacuole. In this article we report the rearrangement of host cell organelles and elements of the cytoskeleton of LLCMK2 cells, a lineage derived from green monkey kidney epithelial cells, in response to infection by T. gondii tachyzoites. Transmission electron microscopy made on flat embedded monolayers cut horizontally to the apical side of the cells or field emission scanning electron microscopy of monolayers scraped with scotch tape before sputtering showed that association of mitochondria to the vacuole is much less frequent than previously described. On the other hand, all parasitophorous vacuoles were surrounded by elements of the endoplasmic reticulum. These data were complemented by observations by laser scanning microscopy using fluorescent probes from mitochondria and endoplasmic reticulum and reinforced by three-dimensional reconstruction from serial sections observed by transmission electron microscopy and labeling of mitochondria and endoplasmic reticulum by fluorescent probes.

Research paper thumbnail of Interrelations between the Parasitophorous Vacuole of Toxoplasma gondii and Host Cell Organelles

Microscopy and Microanalysis, 2005

Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and m... more Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and multiplying in any nucleated cell of warm-blooded animals. Its survival strategies include escape from fusion of the parasitophorous vacuole with host cell lysosomes and rearrangement of host cell organelles in relation to the parasitophorous vacuole. In this article we report the rearrangement of host cell organelles and elements of the cytoskeleton of LLCMK2 cells, a lineage derived from green monkey kidney epithelial cells, in response to infection by T. gondii tachyzoites. Transmission electron microscopy made on flat embedded monolayers cut horizontally to the apical side of the cells or field emission scanning electron microscopy of monolayers scraped with scotch tape before sputtering showed that association of mitochondria to the vacuole is much less frequent than previously described. On the other hand, all parasitophorous vacuoles were surrounded by elements of the endoplasmic reticulum. These data were complemented by observations by laser scanning microscopy using fluorescent probes from mitochondria and endoplasmic reticulum and reinforced by three-dimensional reconstruction from serial sections observed by transmission electron microscopy and labeling of mitochondria and endoplasmic reticulum by fluorescent probes.

Research paper thumbnail of Spina cortica and Tapetum spinosus, two new microstructures of flight feathers: Description, function and distribution in modern birds

Journal of Structural Biology, 2008

The importance of feathers for the avian group has made them one of the most studied epidermal st... more The importance of feathers for the avian group has made them one of the most studied epidermal structures both from the morphological and evolutionary point of view. Surprisingly, our observations by Scanning Electron Microscopy detected the presence of two structures widely distributed within different avian groups and not yet described. In this paper we describe these two new structures (Spina cortica and Tapetum spinosus) and map their distribution within modern birds. The S. cortica is a thorn-like microstructure that grows on the barb cortex and the T. spinosus is the assemblage of these thorns. The distribution of these new structures among birds and their morphological diversity could be of great interest to taxonomists and evolutionary biologists interested in the origin of bird flight.

Research paper thumbnail of Spina cortica and Tapetum spinosus, two new microstructures of flight feathers: Description, function and distribution in modern birds

The importance of feathers for the avian group has made them one of the most studied epidermal st... more The importance of feathers for the avian group has made them one of the most studied epidermal structures both from the morphological and evolutionary point of view. Surprisingly, our observations by Scanning Electron Microscopy detected the presence of two structures widely distributed within different avian groups and not yet described. In this paper we describe these two new structures (Spina cortica and Tapetum spinosus) and map their distribution within modern birds. The S. cortica is a thorn-like microstructure that grows on the barb cortex and the T. spinosus is the assemblage of these thorns. The distribution of these new structures among birds and their morphological diversity could be of great interest to taxonomists and evolutionary biologists interested in the origin of bird flight.