Relating form to function in the hummingbird feeding apparatus

A complete understanding of the feeding structures is fundamental in order to study how animals survive. Some birds use long and protrusible tongues as the main tool to collect their central caloric source (e.g., woodpeckers and nectarivores). Hummingbirds are the oldest and most diverse clade of nectarivorous vertebrates, being a perfect subject to study tongue specializations. Their tongue functions to intraorally transport arthropods through their long bills and enables them to exploit the nectarivorous niche by collecting small amounts of liquid, therefore it is of vital importance to study its anatomy and structure at various scales. I focused on the portions of the hummingbird tongue that have been shown to be key for understanding their feeding mechanisms. I used histology, transmission and scanning electron microscopy, microCT, andex-vivoexperiments in order to advance the comprehension of the morphology and functioning of the hummingbird feeding apparatus. I found that hummingbird tongues are composed mainly of thin cornified epithelium, lack papillae, and completely fill the internal cast of the rostral oropharyngeal cavity. Understanding this puzzle-piece match between bill and tongue will be essential for the study of intraoral transport of nectar. Likewise, I found that the structural composition and tissue architecture of the tongue groove walls provide the rostral portion of the tongue with elastic properties that are central to the study of tongue-nectar interactions during the feeding process. Detailed studies on hummingbirds set the basis for comparisons with other nectar-feeding birds and contribute to comprehend the natural solutions to collecting liquids in the most efficient way possible.

Download Full-text

Relating form to function in the hummingbird feeding apparatus

10.7287/peerj.preprints.2986v1 ◽

2017 ◽

Author(s):

Alejandro Rico-Guevara

Keyword(s):

Ex Vivo ◽

Main Tool ◽

Feeding Apparatus ◽

Tissue Architecture ◽

Complete Understanding ◽

Nectar Feeding ◽

Puzzle Piece ◽

Oropharyngeal Cavity ◽

Feeding Process ◽

Rostral Portion

A complete understanding of the feeding structures is fundamental in order to study how animals survive. Some birds use long and protrusible tongues as the main tool to collect their central caloric source (e.g. woodpeckers and nectarivores). Hummingbirds are the oldest and most diverse clade of nectarivorous vertebrates, being a perfect subject to study tongue specializations. Their tongue functions to intraorally transport arthropods through their long bills and enables them to exploit the nectarivorous niche by collecting small amounts of liquid, therefore it is of vital importance to study its anatomy and structure at various scales. I focused on the portions of the hummingbird tongue that have been shown to be key for understanding their feeding mechanisms. I used histology, transmission and scanning electron microscopy, microCT, and ex-vivo experiments in order to advance the comprehension of the morphology and functioning of the hummingbird feeding apparatus. I found that hummingbird tongues are composed mainly of thin cornified epithelium, lack papillae, and completely fill the internal cast of the rostral oropharyngeal cavity. Understanding this puzzle-piece match between bill and tongue will be essential for the study of intraoral transport of nectar. Likewise, I found that the structural composition and tissue architecture of the tongue groove walls provide the rostral portion of the tongue with elastic properties that are central to the study of tongue-nectar interactions during the feeding process. Detailed studies on hummingbirds set the basis for comparisons with other nectar-feeding birds and contribute to comprehend the natural solutions to collecting liquids in the most efficient way possible.

Download Full-text

The Feeding Apparatus of the Barnacle Nauplius Larva: A Scanning Electron Microscope Study

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400018944 ◽

1976 ◽

Vol 56 (2) ◽

pp. 321-326 ◽

Cited By ~ 12

Author(s):

P. S. Rainbow ◽

G. Walker

Keyword(s):

Light Microscope ◽

Feeding Apparatus ◽

Light Microscope Level ◽

Scanning Electron Microscope Study ◽

Barnacle Species ◽

Nauplius Larva ◽

Feeding Process ◽

Relationship Of ◽

Balanus Balanoides ◽

Limb Structure

INTRODUCTIONThe nauplius stages of many barnacle species have been described at the light microscope level (Bassindale, 1936; Knight-Jones & Waugh, 1949; Costlow & Bookhout, 1957; Karande, 1974), including those of the British barnacles Balanus balanoides (L.) andBalanus hameri (Ascanius) (Crisp, 1962a, b). Although these studies have included full descriptions of limb structure, it is not possible with the light microscope to resolve the topographical relationship of the limbs and other structures associated with feeding. Attempts to describe the feeding process of barnacle nauplii (Lochhead, 1936; Norris & Crisp, 1953; Gauld, 1959; Moyse & Knight-Jones, 1967) have necessarily been limited for this reason.

Download Full-text

Pollination by Flies

Pollination and Floral Ecology ◽

10.23943/princeton/9780691128610.003.0013 ◽

2011 ◽

Author(s):

Pat Willmer

Keyword(s):

Strong Preference ◽

Diverse Group ◽

Feeding Apparatus ◽

Nectar Feeding ◽

Fly Pollination ◽

Adult Diet

This chapter focuses on pollination by flies, a very diverse group of insects of the order Diptera. Many types of fly have the ability to regurgitate saliva onto potential foodstuffs, making the material more liquid and manageable, and some use “bubbling” behavior to speed evaporation of excessively dilute fluids. Many groups have a strong preference for sugary fluids, and therefore commonly take some nectar as part of their adult diet; others feed on pollen. The chapter first provides an overview of the fly’s feeding apparatus as well as its sensory and behavioral capacities before discussing generalist flowers that are favored by a multitude of flies. It then considers specialist flower types that attract nectar-feeding flies, hoverfly flower types, and carrion-fly flower types. It concludes with an analysis of some other specialist cases of fly pollination of flowers.

Download Full-text

Four-dimensional hydrogel-in-hydrogel bioprinting for the spatiotemporal control of organoid and organotypic cultures

10.21203/rs.3.rs-952864/v1 ◽

2021 ◽

Author(s):

Nicola Elvassore ◽

Anna Urciuolo ◽

Giovanni Giobbe ◽

Yixiao Dong ◽

Federica Michielin ◽

...

Keyword(s):

Ex Vivo ◽

Morphological Changes ◽

Three Dimensional ◽

Culture Conditions ◽

Developmental Trajectory ◽

Self Organization ◽

Tissue Architecture ◽

Initial Culture ◽

Spatiotemporal Control

Abstract Tissue architecture is a driving force for morphogenetic processes during development as well as for several physiological and regenerative responses. Far from being a passive static environment, tissue architecture is highly dynamic. Hydrogel technology reproduces in vitro geometrical and mechanical constrains that control the three-dimensional self-organization of (3D) organoids and organ-like cultures. This control is restricted to the initial culture conditions and cannot be adapted to the dynamic morphological changes of complex 3D cultures during their developmental trajectory. Here, we developed a method that overcomes this spatiotemporal limit. Using 2P crosslinking approach, high resolution 3D hydrogel structures can be fabricated within pre-existing hydrogel with spatiotemporal (four-dimensional, 4D) control relative to ex-vivo organotypic or organoid culture. This hydrogel-in-hydrogel bioprinting approach enables to continuously instruct the self-organization of the evolving 3D organ-like cultures.

Download Full-text

THE FINE STRUCTURE AND FUNCTION OF THE TENTACLE IN TOKOPHRYA INFUSIONUM

The Journal of Cell Biology ◽

10.1083/jcb.25.3.459 ◽

1965 ◽

Vol 25 (3) ◽

pp. 459-477 ◽

Cited By ~ 75

Author(s):

Maria A. Rudzinska

Keyword(s):

Electron Microscope Study ◽

Structure And Function ◽

The Body ◽

Feeding Apparatus ◽

Dense Bodies ◽

Structural Details ◽

Flow Through ◽

Feeding Process ◽

Fine Structure And Function ◽

And Function

The feeding apparatus of Suctoria consists of long, thin, stiff tubes called tentacles. When a swimming prey attaches to the tip of the tentacle a number of events follow in rapid succession. The tentacle broadens, a stream of tiny granules starts to move upward at its periphery to the tip, the prey becomes immobilized and shortly thereafter the cytoplasm of the still living prey begins to flow through the center of the tentacle to the body of the predator. An electron microscope study of the tentacle in Tokophrya infusionum, a protozoan of the subclass Suctoria, has disclosed a number of structural details which help to clarify some of the mechanisms involved in this unusual way of feeding. Each tentacle is composed of two concentric tubes. The lumen of the inner tube is surrounded by 49 tubular fibrils most probably of contractile nature. In the inner tube the cytoplasm of the prey is present during feeding, and in the outer tube are small dense bodies. It was found that the dense bodies originate in the cytoplasm of Tokophrya. They have an elongate, missile-like appearance, pointed at one end, rounded at the other, and are composed of several distinct segments. At the tip of the tentacle they penetrate the plasma membrane, with their pointed ends sticking out. It is assumed that the missile-like bodies play a major role in the feeding process. Their composite structure suggests that they might contain a number of enzymes which most probably are responsible for the various events preceding the actual food intake.

Download Full-text

Gross morphology of rhea oropharyngeal cavity

Pesquisa Veterinária Brasileira ◽

10.1590/s0100-736x2012001300011 ◽

2012 ◽

Vol 32 (suppl 1) ◽

pp. 53-59 ◽

Cited By ~ 2

Author(s):

Marcio N. Rodrigues ◽

Catarina N. Tivane ◽

Rafael C. Carvalho ◽

Gleidson B. Oliveira ◽

Roberto S.B. Silva ◽

...

Keyword(s):

Family Studies ◽

Longitudinal Ridge ◽

Rhea Americana ◽

Caudal Region ◽

Pale Pink ◽

Contradictory Information ◽

Oropharyngeal Cavity ◽

Rostral Region ◽

Rostral Portion ◽

Laryngeal Mound

The rhea (Rhea americana americana) is an american bird belonging to Ratite's family. Studies related to its morphology are still scarce. This study aims to describe the macroscopic structures of the oropharyngeal cavity. Five heads (2 to 6 months old) formalin preserved were anatomically dissected to expose the oropharynx. The oropharynx of the rhea was "bell-shaped" composed by the maxillary and mandibular rhamphotheca. The roof and floor presented two distinct regions different in colour of the mucosa. The rostral region was pale pink contrasting to grey coloured caudal region. The median longitudinal ridge extended rostrally from the apex of the choana to the tip of the beak in the roof and it is clearly more prominent and rigid than the homolog in the floor that appeared thin and stretched merely along the rostral portion of the regio interramalis. The floor was formed by the interramal region, (regio interramalis) tongue and laryngeal mound containing glove-shaped glottis. This study confirmed the basic morphology of the oropharinx of the rhea. However, important morphological information not previously described is highlighted and contradictory information present in the literature is clarified.

Download Full-text

Conformation of Ribosomes from Escherichia Coli

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051062 ◽

1974 ◽

Vol 32 ◽

pp. 210-211

Author(s):

M. Boublik ◽

W. Hellmann ◽

F. Jenkins

Keyword(s):

Binding Sites ◽

Ribosomal Proteins ◽

Fluorescent Dyes ◽

Protein Biosynthesis ◽

Three Dimensional ◽

Spatial Arrangement ◽

Dimensional Structure ◽

Complete Understanding ◽

And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Download Full-text

The Nature of Oxide Surfaces: Topographic and Electronic Structure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100150666 ◽

1993 ◽

Vol 51 ◽

pp. 966-967

Author(s):

Dawn A. Bonnell ◽

Yong Liang

Keyword(s):

Transition Metal Oxides ◽

Electronic Structures ◽

Recent Progress ◽

Spatial Localization ◽

Level Of Detail ◽

Scanning Tunneling ◽

Oxide Surfaces ◽

Tunneling Microscopy ◽

Considerable Effort ◽

Complete Understanding

Recent progress in the application of scanning tunneling microscopy (STM) and tunneling spectroscopy (STS) to oxide surfaces has allowed issues of image formation mechanism and spatial resolution limitations to be addressed. As the STM analyses of oxide surfaces continues, it is becoming clear that the geometric and electronic structures of these surfaces are intrinsically complex. Since STM requires conductivity, the oxides in question are transition metal oxides that accommodate aliovalent dopants or nonstoichiometry to produce mobile carriers. To date, considerable effort has been directed toward probing the structures and reactivities of ZnO polar and nonpolar surfaces, TiO2 (110) and (001) surfaces and the SrTiO3 (001) surface, with a view towards integrating these results with the vast amount of previous surface analysis (LEED and photoemission) to build a more complete understanding of these surfaces. However, the spatial localization of the STM/STS provides a level of detail that leads to conclusions somewhat different from those made earlier.

Download Full-text

Correlation of γ-radioactivity and Scanning Electron Microscopy in measurement of retention of 111Indium-labeled canine endothelial cells on synthetic vascular grafts

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156419 ◽

1989 ◽

Vol 47 ◽

pp. 886-887

Author(s):

E.J. Prendiville ◽

S. Laliberté Verdon ◽

K. E. Gould ◽

K. Ramberg ◽

R. J. Connolly ◽

...

Keyword(s):

Blood Flow ◽

Ex Vivo ◽

Vascular Grafts ◽

Retention Data ◽

Vascular Prostheses ◽

Group 4 ◽

Human Fibronectin ◽

Insufficient Time ◽

Group 3 ◽

Group 2

Endothelial cell (EC) seeding is postulated as a mechanism of improving patency in small caliber vascular grafts. However the majority of seeded EC are lost within 24 hours of restoration of blood flow in previous canine studies . We postulate that the cells have insufficient time to fully develop their attachment to the graft surface prior to exposure to hemodynamic stress. We allowed EC to incubate on fibronectin-coated ePTFE grafts for four different time periods after seeding and measured EC retention after perfusion in a canine ex vivo shunt circuit.Autologous canine EC, were enzymatically harvested, grown to confluence, and labeled with 30 μCi 111 Indium-oxine/80 cm 2 flask. Four groups of 5 cm x 4 mm ID ePTFE vascular prostheses were coated with 1.5 μg/cm.2 human fibronectin, and seeded with 1.5 x 105 EC/ cm.2. After seeding grafts in Group 1 were incubated in complete growth medium for 90 minutes, Group 2 were incubated for 24 hours, Group 3 for 72 hours and Group 4 for 6 days. Grafts were then placed in the canine ex vivo circuit, constructed between femoral artery and vein, and subjected to blood flow of 75 ml per minute for 6 hours. Continuous counting of γ-activity was made possible by placing the seeded graft inside the γ-counter detection crystal for the duration of perfusion. EC retention data after 30 minutes, 2 hours and 6 hours of flow are shown in the table.

Download Full-text